29th Miller Conference on Radiation Chemistry

14-19 March 2015

The Hydro Windermere Bowness-on-Windermere, United Kingdom

1

29th Miller Conference on Radiation Chemistry

14-19 March 2015

The Hydro Windermere

Bowness-on-Windermere, United Kingdom

Organiser

Dr. Nicholas GREEN

Chair persons

Laszlo WOJNAROVITS (Hungary)

Krzysztof BOBROWSKI (Poland)

Ortwin BREDE (Germany)

Erzsebet TAKACS (Hungary)

Simon PIMBLOTT (UK)

Jay LA VERNE (USA)

Nicholas GREEN (UK)

Mats JONSSON (Sweden)

Ian CARMICHAEL (USA)

Jim WISHART (USA)

Mohamad AL-SHEIKHLY (USA)

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Website: http://millerconf2015.chem.ox.ac.uk/home

Webmaster/booklet co-editor: Dr. Pavlina SCHMITZ

Conference office

University of Oxford Department of Chemistry

Inorganic Chemistry Laboratory South Parks Road Oxford OX1 3QR United Kingdom

tel.: +44-1865-282760

e-mail: nicholas.green@chem.ox.ac.uk

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Young Scientist Speakers

Erzsébet ILLES (Hungary)

Zhenpeng CUI (France)

Konrad SKOTNICKI (Poland)

Jun MA (France)

Stephanie WALSH (Canada)

Chris POLIN (UK)

Josiane KADDISSY (France)

Björn DAHLGREN (Sweden)

Greg HORNE (UK)

Mohammed GHALEI (France)

Jennifer SCHOFIELD (UK)

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WELCOME

Dear Participants, Welcome to wonderful Windermere. I hope you have an interesting and successful conference. Windermere is in the middle of the Lake District National Park, which has been established since 1951. It is a centre for hill-walking and water activities. Suggested afternoon walks. Leaflets with suggested walks based on Bowness and nearby places of interest are available in the Miller Conference box. Tourist guide books may be found in the Miller Conference box in the lounge. Please do not remove these from the hotel lounge. More energetic participants may wish to plan more ambitious walks on the high fells. Please leave a note of your party members, intended route and (realistic) anticipated time of arrival back at the hotel with the hotel reception, and please inform reception on your return. Take with you a note of the hotel telephone number: 015394 44455. About Bowness and Windermere. Bowness is an older village than Windermere, dating from the 10th or 11th century. (The Romans built a fort at Ambleside and a villa on Belle Isle, opposite Bowness.) The name Windermere is derived from Vinland’s Mere, named after a viking chief. Windermere was a small village called Birthwaite until the railway arrived in 1847 (-thwaite is a viking place-name ending). St Martin’s church in Bowness is not the original, the present 15th century building replacing that destroyed by fire in 1480. The east window includes 15th century stained glass. Windermere is England's longest lake, 17 km (10.5 miles) long and 60 m (200 ft) deep. There is a ferry across the lake from Bowness Tourist information centre. The Bowness Café and Information centre is open 7 days a week from 9.30 to 16.00. Glebe Road Bowness on Windermere Cumbria LA23 3HJ The Hotel By English law the Hotel is a non-smoking area. Meals Welcome drink: Saturday 14 March at 1800 in the ballroom. Breakfast from 0730 to 0830. On Thursday 19 March, from 0700 to 0830. Participants leaving early on Thursday 19 March may obtain continental breakfast before 0700 by pre- booking this at the hotel reception. Morning coffee/tea. Served at the end of the first session each day (served outside the conference room). Lunch from 1315 each day. Dinner at 1830 each day. Conference Dinner Wednesday 18 March, 2000 (pre-dinner drinks at 1930). Bar. The bar will open at about 1100 each day. Drinks with meals. Wine on the table is included in the Conference Dinner, on Wednesday only, free of charge. Drinks ordered with other meals will be charged. Ask for the wine waiter.

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The Miller Trust for Radiation Chemistry The Miller Trust for Radiation Chemistry is a charity registered in the United Kingdom (registration number 802533). The objects of the Trust are for the advancement of public education concerning the chemical effects of radiation. The Trust was organised by former colleagues and friends of the late Dr Nicholas Miller, with one of the aims being to organise regular scientific conferences in the UK and other countries in Europe in the general subject area of radiation chemistry. Miller Conferences have been held at two-year intervals since 1959, and provide a European equivalent of the Gordon Research Conference in Radiation Chemistry, long-established in the US. Dr Nicholas Miller Nicholas Miller was born in Liverpool on 4 July 1916. He gained his PhD in chemistry at Imperial College, London in 1939 and then spent two years at the University of California, Berkeley and California Institute of Technology, Pasadena. He moved to Suffield, Alberta, Canada and worked on chemical warfare with the Department of National Defence until 1943. He then began his involvement with radiation chemistry when he joined the Canadian National Research Council staff in Montreal and Chalk River, Ontario, where he worked with F S Dainton on the British/Canadian atomic energy project. Returning in 1946 to the United Kingdom, to the Department of Natural Philosophy at the University of Edinburgh, he established his reputation as a leading worker in the then young science of radiation chemistry. He died on 5 May 1958. (Obituary: International Journal of Radiation Biology, 1959,1, 2). Origins of the Miller Trust In February 1958, N Miller and R Roberts agreed to organise a British 'Gordon-style' conference on radiation chemistry. Some plans were made but were disrupted by Miller's untimely death in May 1958. F S Dainton and E Collinson joined with R Roberts in organising the first conference, held in Portmeirion, Wales in April 1959. Dainton and Roberts suggested the conference should be named after Miller. A committee elected on 23 April 1959 began the formal organisation of what was to become the Miller Trust. The organisation was modelled after the Gordon Conferences held in the United States, with the emphasis on a base in the United Kingdom but including a strong European involvement by holding conferences every two years, alternating between the United Kingdom and elsewhere in Europe. Formal rules for the election of the Committee and the management of Miller Conferences were drawn up and modified from time to time. Although the name 'Trust' was used from the start, the organisation did not have the legal status of a charitable trust. After discussion in 1989 with the Charity Commisioners appointed by the Government of the United Kingdom, and after small changes and improvements to the Rules, The Miller Trust for Radiation Chemistry was accepted as a charity registered in the United Kingdom according to English Law on 12 February 1990. Membership of the Miller Trust Membership of the Trust is open to all persons interested in radiation chemistry. The Committee elects to the Trust participants at Miller Conferences, but membership lapse after three Conferences without attendance; re-election is automatic on attending a Miller Conference. Miller Conferences are open to all, but organizers may limit numbers for practical reasons. Committee of the Miller Trust The Committee consists of twelve members of the Trust, of whom seven are citizens of the United Kingdom. It is elected by members of the Trust at the Ordinary General Meeting, normally held every four years. The Committee elects four Officers, and the present Committee, elected in 2013 to serve four years, comprises: Chairman: K Bobrowski; Vice Chairman and Chairman-Elect: M Jonsson; Secretary: E Takacs; Treasurer: N Green; Ordinary Members: Y Berlin, M Mostafavi, P Ulanski, L Wojnarovits, C Dispenza, D Guldi, I Zilbermann. Miller Trust mailing list All participants at any one of the Miller Conferences held in 2011 2013 or 2015 remain members of the Miller Trust and will receive the First Circular of the 2017 Conference. Others should write to the Chairman of the 2017 Conference, Dr C Dispenza.

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Miller conferences 1959-2015 Year Location Organiser 1959 Portmeirion, Wales R Roberts 1961 Portmeirion, Wales F S Dainton 1963 Rocamadour, France M Magat 1965 Portmeirion, Wales W Wild 1967 Kazimierz, Poland J Kroh 1969 Portmeirion, Wales J F Weiss 1971 Sardinia, Italy G Semerano 1973 Portmeirion, Wales J F Baxendale 1975 Bürgenstock, Switzerland T Gaümann 1977 Portmeirion, Wales G Scholes 1979 Nafplion, Greece N Th Rakintzis 1981 Windermere, England G A Salmon 1983 Hünfeld, Germany D Schulte-Frohlinde 1985 Windermere, England A J Swallow 1987 Sopron, Hungary R Schiller 1989 Windermere, England G O Phillips 1991 Giens. France J Belloni 1993 Windermere, England P Wardman 1995 Cervia, Italy Q G Mulazzani 1997 Windermere, England P O’Neill 1999 Doorwerth, Netherlands J M Warman 2001 Windermere, England N J B Green 2003 Bialowieza, Poland J Mayer; J L Gebicki 2005 La Londe les Maures, France M. Spotheim-Maurizot; C. Houée-Levin 2007 Buxton, England S M Pimblott; N Harridge 2009 Keszthely, Hungary E Takacs; L Wojnarovits 2012 Tallberg, Sweden M Jonsson 2013 Dead Sea, Israel I Zilbermann; S Goldstein 2015 Windermere, England N J B Green Miller Conference 2017 This will be held in Italy under the Chairmanship of Dr C Dispenza, (Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Università degli Studi di Palermo, Viale delle Scienze Ed. 6,90128 Palermo and CNR - Istituto di Biofisica (IBF) UOS Palermo, via Ugo La Malfa 153, 90146 Palermo, Italy. e-mail: clelia.dispenza@unipa.it). For further details please contact Clelia Dispenza.

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Scientific Program

Session Title Presenter Chairman 1

Saturday 2000-2045 2045-2130

Radiolytic hydrogen production on the surface of PuO2 Kinetic Studies on the Radiation Chemical Reduction of Graphene Oxide

Sims (UK Kahnt (Germany)

Wojnarovits (Hungary)

2

Sunday 0900-0945 0945-1030

Radical Chemistry (Dieter Asmus) Ascorbate and urate repair of amino acid and protein radicals Selective free radical mechanisms of protein degradation: sequence effects and catalysis by specific amino acids

Domazou (Switzerland) Schöneich (USA)

Bobrowski (Poland)

3

1100-1145 1145-1230

Oxidation of Methionine and related compounds in peptides. From the 2-centre 3 electron bonded radical to the final products. Scavenging and repair of protein radicals: cellular and kinetic studies

Houée-Levin (France) Davies (Denmark)

Brede (Germany)

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1630-1700 1700-1730 1730-1800 1800-1830 1830-1900 2000-2030 2030-2100

Young scientists session Hydrogen peroxide formation during radiolysis of organic compounds Radiolytic Method as a Novel Approach for Synthesis of Nanostructured Conducting Polypyrrole Radiation-induced radical processes involving amino acids and quinoxalin-2-one derivatives relevant to their pharmacological applications Reactivity of Solvated Electron with Hydronium ion in Aqueous and Tetrahydrofuran Solutions Studied by Picosecond Pulse Radiolysis Multigenerational effects of Ra-226 in mammals Very High Yields of the Hydroxyl Radical in Gold Nanoparticle-doped Water Hydrogen generation from irradiated aluminium hydroxides and oxyhydroxides

Erzsébet Illés (Hungary) Zhenpeng Cui (France) Konrad Skotnicki (Poland) Jun Ma (France) Stephanie Walsh (Canada) Chris Polin (UK) Josiane Kaddissy (France)

Takacs (Hungary)

8

2100-2130 2130-2200

Modelling Interfacial Radiation Chemistry Investigation into the Radiolysis of PUREX Solvent Systems

Björn Dahlgren (Sweden) Greg Horne (UK)

5

Monday 0900-0945 0945-1030

Fast processes Experimental evidence for ultrafast oxidation reaction induced by water radical cation H2O•+, Picosecond pulse radiolysis measurements Probing intermediates in the radiation chemistry of ionic liquids

Mostafavi (France) Wishart (USA)

Pimblott (UK)

6

1100-1145 1145-1230 12.30-13.00

Recent developments in pulse radiolysis with time resolved resonance Raman detection Exploring mechanisms of the radiation-induced degradation of ion exchange resins Study α and γ radiolysis of highly concentrated carbonate media and its mechanisms by pulse radiolysis; application for speciation of Tc, Mn and Re

Janik (USA)) Baidak (UK) Ghalei (France)

LaVerne (USA)

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2000-2200

Poster session 1

8

Tuesday 0845-0930 0930-1015 1015-1100

Tracks Experimental and theoretical perspectives of the effect of charge exchange of medium speed ions in various nuclear materials Towards nanoparticle enhanced radiotherapy: A research programme towards better cancer care Icarus, ArgoNeuT, and the search for Dark Matter. Applications of the recombination theory

Schofield (UK) Currell (UK) Wojcik (Poland)

Green (UK)

9

1130-1215

Mechanistic studies on the role of [Cu(CO3)n]2−2n as a water oxidation catalyst

Zilbermann (Israel)

Bobrowski (Poland)

1215-1315

Poster session 2

14.30-16.00

Windermere Lake Cruise

10

1945-2030

Surfaces Radiolytic corrosion occurring at the solid/solution interface investigated at SUBATECH: example of Uranium, Titanium, Technetium

Vandenborre (France)

Jonsson (Sweden)

9

2030-2115 2115-2200

Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion-batteries Overview of properties affecting release of radionuclides from spent nuclear fuel under long-term storage conditions

Le Caer (France) Roth (Sweden)

11

Wednesday 0900-0945 0945-1030

Physics Transport of Charge Carriers in DNA-based Systems beyond One Dimension: Charge Flow across Practically Important Molecular Construct with Complex Architecture Dissociative electron attachment to isotopic and isomeric gas-phase molecules

Berlin (USA) Ptasinska (USA)

Carmichael (USA)

12

1100-1130 1130-1215 1215-1300

The ebeam Vitrine: the latest collection of ebeaming hardware Do proteins protect DNA from radiation damage? Picosecond and Nanosecond Pulse Radiolysis of Melts of Lithium-Potassium Chloride

Bland (UK) Garman (UK) Yamashita (Japan)

Wishart (USA)

13

1700-1730 1745-1830

Polymers Track-etched polymer membranes for research and applications Radiation-synthesized hydrogel-based matrices for cell cultivation

Clochard (France) Kadłubowski (Poland)

Al-Sheikhly (USA)

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ABSTRACTS of

INVITED LECTURES

(in order of presentation)

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Session 1

Radiolytic hydrogen production on the surface of PuO2

HE Sims1, C Gregson2, RM Orr2, RJ Taylor2 and K Webb2 P Cook and J Hobbs3

1 National Nuclear Laboratory, Harwell Science Park, Didcot, Oxon OX11 0QT, UK 2 National Nuclear Laboratory, Central Laboratory, Sellafield, Seascale CA20 1PG, UK 3 Sellafield Ltd. Seascale CA20 1PG, UK PuO2 is stored in sealed cans at Sellafield and so pressurisation is potentially an issue, but is not observed in the vast majority of cases. One possible mechanism for pressurisation is radiolysis of adsorbed water. As part of a program to elucidate the chemical processes occurring in a storage can, yields of hydrogen from PuO2 held in a range of different relative humidity have been measured. Results will be presented which show that GH2 is dependent on the number of water monolayers, but in contrast to other oxides there is no evidence for energy transfer from solid to aqueous phase, and GH2 is lowest in water closest to the oxide surface. Radiation chemistry in the storage cans includes not only surface water but also gases in contact with the high specific surface area solid and in some cases polythene is used as an intermediate containment. Some of these processes will be discussed briefly as will dosimetric issues in these systems.

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Kinetic Studies on the Radiation Chemical Reduction of Graphene Oxide Axel Kahnt1, Siegfried Eigler2, Roman Fluynt3, Wolfgang Knolle3 and Bernd Abel3

1Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, 91058 Erlangen, Germany. E-Mail: axel.kahnt@fau.de 2Department of Chemistry and Pharmacy & Institute of Advanced Materials and Processes (ZMP), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Dr.-Mack Str. 81, 90762 Fürth, Germany. 3Chemical Department, Leibniz Institute of Surface Modification (IOM), Permoserstrasse 15, 04318 Leipzig, Germany. Graphene is a novel material with outstanding electrical properties such as ballistic electron transport. But obtaining monolayer material – required for these outstanding features is challenging and the procedures established so far are not up-scalable towards a large scale production. Graphene oxide on the other hand is per se a monolayer material which – compared to graphene – can be covalently functionalized on its defects. The disadvantage of graphene oxide is that the outstanding electronic properties are lost due to the highly defective sp2 carbon framework. Bearing this in mind the reduction of graphene oxide towards graphene like material (reduced graphene oxide) appears as a promising way and several classical reduction methods such as the reduction with hydrazine were published. But these methods are either not effective or not environmental friendly. Taking this into account we recently published the effective and environmentally friendly reduction of graphene oxide to graphene like material by electron beam radiolysis from aqueous dispersions of graphene oxide. Here we investigated the reduction employing different reducing transients such as e(aq)

-, CO2•-, (CH3)2

•C(OH) or CH3•CH(OH).[1] But details such

as rate constants and the mechanism remained unrevealed. e(aq)

-, H•, CO2•-,

(CH3)2•C(OH),

CH3•CH(OH)

Figure 1. Scheme of the reduction of graphene oxide to reduced graphene oxide utilizing reductive transients. This in mind, we investigated the reduction of three different graphene oxides with e(aq)

-, H•, CO2•-, (CH3)2

•C(OH) and CH3

•CH(OH) by means of electron pulse radiolysis. From the results we obtained the rate constants for these reactions and found solid evidence that the reduction for all investigated transients – besides e(aq)

- – occur in a two-step mechanism, i.e., first radical addition followed by reductive elimination. References [1] R. Flyunt, W. Knolle, A. Kahnt, A. Prager, A. Lotnyk, J. Malig, D. Guldi, B. Abel, Int. J. Rad. Biol. 2014, 90, 486-494.

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Session 2

Ascorbate and urate repair amino acid and protein radicals Anastasia S. Domazou,1 Janusz M. Gebicki,2 Izoldi Kammenou3 and Willem H. Koppenol1 1Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Zurich 2 Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia 3 Institute of Analytical Chemistry, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland domazou@inorg.chem.ethz.ch Protein radicals are the primary products of the damaging one-electron oxidation of proteins by oxidising species such as HO·, FeO2+, or ONOOH. In the presence of O2 they are converted to the corresponding protein peroxyl radicals and react further to form hydroperoxides. Endogenous antioxidants, such as ascorbate and urate, belong to the defence system of organisms and are considered to prevent or repair damage. Under conditions of oxidative stress, reduced levels of antioxidants have been measured. Ascorbate and urate repair efficiently tryptophan (Trp·) and tyrosyl radicals (Tyr·) in a number of proteins.1-3 They also reduce rapidly the peroxyl radicals of the N-acetylamide derivatives of glycine (N-ac-Gly-amide), alanine (N-ac-Ala-amide) and proline (N-ac-Pro-amide).4 In contrast, both antioxidants reduce the C-centered radicals of a-methylalanine (a-metAla), N-ac-Gly-amide, N-ac-Ala-amide and N-ac-Pro-amide considerably slower, with rate constants up to 106 M–1 s–1. The reduction is strongly dependent on the amino acid. It appears that the reduction of β-C radicals is faster than that of α-C. Somewhat surprisingly, these amino acid radicals react rapidly with the ascorbyl and urate radicals formed, with rates constants of 108-109 M–1 s–1. This reaction competes with the reaction with antioxidants. Our results demonstrate that, in most cases and under physiological conditions, reactions of protein C-centered radicals with ascorbate/urate cannot effectively compete with reactions of such radicals with O2. Nevertheless, ascorbate and urate appear to be important protective agents against biological damage: they (a) repair Trp· and Tyr· in proteins, and (b) reduce PrOO· to the corresponding PrOOH, thereby temporarily halting a peroxidative chain reaction. The loss of ascorbate and urate in living organisms under oxidative stress is likely to be caused by their reactions with protein radicals, and is to be expected on the basis of their protective role. [1] B.M. Hoey and J. Butler Biochim. Biophys. Acta 1984, 791, 212-218. [2] R. Santus, L.K. Patterson, G.L. Hug, M. Basin, J.C. Mazière, P. Morlière Free Radic. Res. 2000, 33, 383-391. [3] A.S. Domazou, W.H. Koppenol and J.M. Gebicki Free Radic. Biol. Med. 2009, 46, 1049-1057. [4] A.S. Domazou, V. Zelenay, W.H. Koppenol and J.M. Gebicki Free Radic. Biol. Med. 2012, 53, 1565-1573.

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Selective free radical mechanisms of protein degradation: sequence effects and catalysis by

specific amino acids

Christian Schöneich Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA Protein oxidation is a hallmark of oxidative stress and aging. It is also of increasing concern to the biotechnology industry, where the development of efficacious and safe protein therapeutics requires potent molecules with no or minimal immunogenicity. Frequently, protein oxidation is the result of free radical reactions, where these radicals are generated by enzymes, metabolic processes, environmental stress, or, in the case of protein formulations, the decomposition of formulation constituents. The pathways of protein oxidation by free radical reactions are complex, and often initial target sites on proteins are not the sites where the ultimate damage accrues, i.e. the result of radical transfer processes along the protein. The rational development of stable protein therapeutics would greatly benefit from predictive tools to assess the risk of a given protein sequence to undergo oxidative degradation. In order to develop such predictive tools, mechanisms and the effects of sequence and structure on these mechanisms must be known. This presentation will provide examples for selective radical reactions in amino acids, peptides and proteins, the contribution of kinetic and thermodynamic parameters on selectivity, and the effect of sequence, structure and environment on these reactions. In these examples, the focus will be on sulfur-centered radicals from cysteine and methionine, the generation and characterization of novel products, and the potential consequences for protein structure, activity and immunogenicity.

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Session 3

Oxidation of Methionine and related compounds in peptides. From the 2-centre 3 electron

bonded radical to the final products

Chantal Houée Levin Laboratoire de Chimie Physique, UMR 8000 CNRS-Univ. Paris Sud, 91405 Orsay France Chantal.houee@u-psud.fr The protein residue Methionine (Met) is one of the main targets of oxidizing free radicals produced in oxidative stress. Its oxidation can cause deleterious consequences during oxidative stress (neurodegenerative diseases, aging etc.). Pulse radiolysis and flash photolysis data confirm that the thioether function is the reactive place. However, despite the numerous studies concentrated on the one-electron oxidation processes of the methionine residue, some aspects of the processes still need to be further investigated and especially the fate of free radicals leading to stable products. The complexity of the structure of the oxidized free radicals has been explored by pulse radiolysis. It is known that they can have various structures most of the time involving two centre- three electron bond between the sulphur cation and any atom having a lone pair. Thus we have undertaken the identification of the final compounds by mass spectrometry coupled to infra red detection (IRMPD). Several compounds other than the well-known sulfoxide were found, which allowed to revisit the total mechanism of oxidation of methionine. In addition, it is known that methionine is the starting point of oxidation of other amino-acids such as tyrosine through intramolecular electron transfer (IET). We have explored the thermodynamics of the IET and the role of the residues other than methionine and tyrosine in a peptide, methionine enkephalin, by various computational methods. In this transfer, the other residues play a minor role even if the distance between both partners (methionine and tyrosine) is quite large.

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Scavenging and repair of protein radicals: cellular and kinetic studies

Michael J. Davies

Panum Institute, University of Copenhagen, Blegdamsvej 3, Copenhagen 2200, Denmark Protein oxidation occurs in animals and humans, particularly with ageing, inflammation, radiation exposure (UV, g-, X-ray etc) and other factors (e.g. exposure to drugs, pollutants, mineral fibres, chemicals). Each of these processes has been linked with increased oxidant formation. Oxidation has been detected in humans and animals, with increased levels in diseased / aged samples compared to healthy tissues. In some cases there is good evidence that oxidative damage is causal in the observed pathology. This damage is associated with increased morbidity and mortality, and has massive economic and social costs. Oxidation is also a major cause of deterioration of foods and pharmaceuticals, and adversely impacts on agricultural production via stress damage to plants. Despite this wealth of evidence for increased levels of protein modification arising from oxidation reactions, there is still limited information available as to the kinetics and precise mechanisms of protein damage, and the quantitative importance of different oxidants and degradation pathways. This is limiting the rational development of agents that may prevent damage, a topic that is of critical importance to human health, the food and pharmaceutical industries and the agricultural sectors. Considerable data now supports the hypothesis that protein radicals are not inert, and there is accumulating evidence that these species can induce damage to other biological targets. The occurrence of such damage might be modulated by agents that efficiently scavenge protein radicals. Consequently, the potential protective reactions of long-lived nitroxide radicals exemplified by TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl radical) and related species has been examined against protein damage in chemical, cellular and animal systems. Pulse radiolysis was employed to determine rate constants, k, for reaction of TEMPO with TyrO• and TrpN• generated on N-Ac-Tyr-amide and N-Ac-Trp-amide with values of k ~108 and 7 × 106 M-1 s-1 determined, respectively. Analogous studies with lysozyme, chymotrypsin and pepsin yielded k for TEMPO reacting with TrpN• ranging from 1.5 × 107 (lysozyme) to 1.1 × 108 (pepsin) M-1 s-1. Pepsin-derived TyrO• reacted with TEMPO with k ~ 4 × 107 M-1 s-1; analogous reactions for lysozyme and chymotrypsin TyrO• were much slower. These data indicate that TEMPO can inhibit secondary reactions of both TyrO• and TrpN•, though this is protein dependent. Analogous experiments with other nitroxide radicals indicates that ring size and charge do not markedly affect the efficacy of these reactions under most conditions. Other compounds such as selenium species (selenols and seleno ethers) also afford protection though, in contrast, this is highly structure dependent. Extension of these studies to macrophage cell pre-treated with TEMPO has provided evidence of protection against photo-induced loss of cell viability and Tyr oxidation, with the nitroxide more effective than the parent amine or hydroxylamine. However these studies and related experiments have uncovered other physiological effects of nitroxides including enzyme inhibition, which may also contribute to their positive biological actions.

17

Session 5

Experimental evidence for ultrafast oxidation reaction induced by water radical cation H2O•+, Picosecond pulse radiolysis measurements

Mehran Mostafavi, Laboratoire de Chimie Physique, CNRS / Paris-Sud University, Buldg. 349, 91405 Orsay, France

*email: mehran.mostafavi@u-psud.fr

One electron oxidation is an important class of chemical reactions in solution. When the water molecule is ionized the primary species formed is the radical cation H2O•+ that subsequently undergoes proton transfer, yielding H3O+ and OH• radical. In solutions containing high concentration of NaCl, NaBr or HNO3, it was difficult to reach the clear conclusion about the possible reaction of H2O•+ with Cl-, Br- and NO3

-, as OH• radicals may also contribute to the oxidation of these anions. However, it was suggested that the ultrafast proton transfer reaction of the radical cation H2O•+ could compete with the electron transfer reaction. The radiation effect on concentrated aqueous solutions was studied during 60 and 90s of last century. The time resolved measurements were limited to the microsecond and nanosecond range. The yields of the direct effect given in the published works were limited to these time windows and the spur reactions of the radicals produced by direct effect were often ignored or not discussed. Moreover, the reactivity of short lived radical cation, H2O•+ was evoked without deducing a firm conclusion about its contribution on the oxidation mechanism of the solute. Picosecond pulse radiolysis is a great method allowing measuring the yields at ultrashort times when the spur reactions are still negligible. Several studies in highly concentrated solutions were undertaken.1-7 Together with the theoretical

1 Balcerzyk, A.; Schmidhammer, U.; El Omar, A. K. ; Jeunesse, P. ; Larbre J. P.,

Mostafavi. M. J. Phys. Chem. A. 2011, 115, 4326.

2 El Omar, A. K. ; Schmidhammer, U. ; Rousseau, B. ; LaVerne, J. ; Mostafavi, M.

J. Phys. Chem. A. 2012, 116, 11509.

3 Balcerzyk, A.; LaVerne, J.; Mostafavi, M. J. Phys. Chem. A. 2011, 115, 9151.

4 Balcerzyk, A.; El Omar, A. K.; Schmidhammer, U.; Pernot, P.; Mostafavi. M. J.

Phys. Chem A. 2012, 116, 7302.

5 El Omar, A. K. ; Schmidhammer, U. ; Balcerzyk, A.; LaVerne, J.; Mostafavi, M.

J. Phys. Chem. A. 2013, 117, 2287.

6 Ma, J.; Schmidhammer, U.; Mostafavi, M. Journal of Physical Chemistry B 2014,

118, 1.

7 Ma, J.; Schmidhammer, U.; Mostafavi, M. Journal of Physical Chemistry A 2014,

118, 4030.

simulations, it was suggested that for highly concentrated solutions the proton transfer reaction between H2O•+ and a water molecule, becomes less efficient if the number of water molecules in close proximity of the radical cation decreases.

0,0 0,2 0,4 0,6 0,8 1,00,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

Concentration (mol L-1)8

Oxidated by

Yiel

d of

sul

fate

radi

cal x

107 m

ol J

-1

Electron fraction (fs)

Oxidaté par Postive Hole Direct Effect

10 2 4 6 10 12 14 16 18

Radiolytic yield of radical sulfate measured 10 p after the pulse versus electron

fraction of sulfuric acid in solution.

Aqueous solutions containing sulfuric acid and phosphoric

acid are studied by picosecond pulse radiolysis. The analysis of the kinetics show that the radicals of sulfuric and phosphoric acid are formed within the picosecond electron pulse via two parallel mechanisms: direct electron detachment by the electron pulse and oxidation by the radical cation of water H2O•+. The yield of this radical is deduced from the analysis of the observed kinetics.

18

Probing intermediates in the radiation chemistry of ionic liquids James F. Wishart *E-mail: wishart@bnl.gov Chemistry Department, Brookhaven National Laboratory, Upton, NY, 11973 USA Ionic liquids are becoming an important component of many advanced devices and technologies.1 A fair number of these applications, such as photoelectrochemical solar cells, high-performance batteries and recycling of spent nuclear fuel, expose ionic liquids to extreme conditions where they are subject to ionization or to the injection of excess charges.2 It is thus important to understand what happens to ionic liquids under those conditions, and the unique combination of properties they possess leads to significant differences in behaviour compared to familiar liquids. From the standpoint of their radiation chemistry, the most important of these properties are: 1) the molecular-scale structural heterogeneity of ionic liquids, in which distinct polar, non-polar and interfacial environments exist; and 2) dynamical heterogeneity characteristic of glassy fluids combined with significant viscosities, which extend the dynamical response of ionic liquids over several orders of magnitude in time. This presentation will discuss the reactivity of transient species produced by radiolysis of ionic liquids, including processes on picosecond time scales and intermediates on longer timescales that are detected by their infrared vibrational signatures.3

This work, and use of the LEAF Facility of the BNL Accelerator Center for Energy Research, was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences, under contracts DE-AC02-98-CH10886 and DE-SC0012704. References 1. Wishart, J. F. Energy Environ. Sci. 2009, 2, 956-961. 2. Wishart, J. F. J. Phys. Chem. Lett. 2010, 1, 3225-3231. 3. Grills, D. C.; Jaime A. Farrington; Layne, B. H.; Preses, J. M.; Bernstein, H. J.; Wishart, J. F., Rev. Sci. Instrum.,

submitted.

19

Session 6

Recent developments in pulse radiolysis with time resolved resonance Raman detection

Ireneusz Janik Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA The innovations in the pulse radiolysis setup with time resolved resonance Raman (TRRR) detection at the Notre Dame Radiation Laboratory will be presented. Recent improvements in this TRRR instrumentation setup allowed us to reduce the overall volume of the solutions required to perform typical pulse radiolysis TRRR studies and the signal collection times by three and two orders of magnitude, respectively. Such a dramatic improvement has allowed us to perform studies never before attempted. Examples of TRRR measurements of radical intermediates generated in water, which absorb light in the spectral range from the deep ultraviolet to the visible, will be presented. Based on the obtained spectral information, interesting physical properties like dissociation energies, electron photo-detachment energies, excitation profiles as well as specific solvation effects of the studied radical intermediates will be discussed. Exploring Mechanisms of the Radiation-Induced Degradation of Ion Exchange Resins

Aliaksandr Baidak Dalton Cumbrian Facility, The University of Manchester, United Kingdom Operation of Light Water Reactors (LWRs) imposes strict requirements on the quality of a coolant. It is well understood that long-term viability of the structural elements inside a nuclear reactor strongly depends on water chemistry conditions. Ion exchange resins play a pivotal role in effective control and maintenance of water chemistry conditions, under which corrosion is suppressed and transport of corrosion products and radioactive isotopes is minimised [1]. Therefore, ion exchange resins are vital to the prolonged lifetime of a reactor system and to the maintenance of a safe working environment in and around the plant. Ion exchange resins undergo chemical degradation due to elevated temperatures and ionizing radiation. Radiation chemical events involving ion exchange resins include, but are not limited to, the loss of the functional groups, the release of decomposition products to the aqueous media in contact, and the production of potentially flammable/explosive gases such as hydrogen or methane [2]. In order to gain a better understanding of the radiolytic decomposition of ion exchange resins in nuclear reactor environment and in waste form, it is important to identify main degradation products as well as their precursors formed in the radiolysis of a polymer itself or in ion exchange resin/water slurries. In my talk I will present the study of three Purolite® ion exchange resins. Studied polymers represent either strongly acidic or strongly basic polystyrene cation (anion) exchange resins as well as a combination of both in a mixed bed. Molecular hydrogen formation in gamma radiolysis of ion exchange resin/water slurries as a function of water content will be discussed. Valuable information concerning main water soluble degradation products (sulphate anion, amine compounds, H+) is provided by ion chromatography and pH measurements. Experiments with scavengers of radiolytically produced intermediates (·OH and e-

aq) demonstrate an important role of these species in the mechanism of degradation of organic ion exchange resins. By performing radiolytic studies of various ion exchange resins in contact with water we were able to evaluate the contribution of water radiolysis to the overall degradation of these polymers. Our work aims to provide simple guidelines for a safe storage of spent ion exchange resins. [1] Ion Exchange Resins for Use in Nuclear Power Plants (the “Wolff” paper), Purolite Ltd, 2012. [2] A review of the Radiation Stability of Ion Exchange Materials, Journal of Radioanalytical and Nuclear Chemistry, Volume 102, Issue 1, pp. 247–268, 1986.

20

Study α and γ radiolysis of highly concentrated carbonate media and its mechanisms by pulse radiolysis; application for speciation of Tc, Mn and Re M.Ghalei(1), J.Vandenborre(1), G. Blain(1), F.Haddad(2), J.Ma(3), M.Mostafavi(3), M. Fattahi‐Vanani(1) (1)Laboratoire SUBATECH – Ecole des Mines de Nantes, CNRS/IN2P3, Université de Nantes 4 rue Alfred Kastler 44307 Nantes cedex 3 France (2)ARRONAX cyclotron – 1, rue Arronax – CS 10112, 44817 Saint Herblain cedex – France (3)Laboratoire Chimie Physique – 15 Avenue Jean Perrin 91405 Orsay – France E‐mail: mohammad.ghalei@subatech.in2p3.fr The aim of this study is using α and γ radiolysis for initiating and controlling the oxidation/reduction mechanism of Tc and its analogous (Mn and Re) in highly concentrated carbonate media (5 M). For obtaining the best experimental conditions (carbonate and Mn concentration, atmosphere), firstly, electrochemistry measurements were performed. After calibration of the absorption band and characterization of the species by electrochemistry, the γ and α radiolysis performed through oxidation of Mn(II) and reduction of Mn(VII). The radiolytic yield of Gγ(‐Mn(VII))=1,54×10‐7 mol.J‐1 and Gα(‐Mn(VII))=2,76×10‐8 mol.J‐1 are deduced showing the effect of dose rate and TEL. The ratios Gγ(‐Mn(VII))/Gα(‐Mn(VII))=5.6 and Gγ(H2)/Gα(H2)=0.48 confirm a radical mechanism for radio‐oxidation/reduction. G(H2) shows catalytic role in case of oxidation for both γ and α radiolysis. The same experiments were performed with Re and Tc but adding formate is necessary because they are more reducing than Mn. Final product oxidation state was determined by XPS and XANES for Mn and Tc respectively. The structural difference between final products of oxidation and reduction by radiolysis is determined by EXAFS. Moreover, picosecond electron pulse‐probe radiolysis was used for different carbonate solutions from low to highest concentration to find the yield of CO3‐ radical formation mechanism through direct effect and reaction with H2O+.

Figure 1. a) Radiolytic yield of H2 and decay of Mn vs. dose for reduction of Mn(VII) under γ and α irradiation in carbonate 5M. b) Decay of absorbance for carbonate radical in carbonate solutions with 5, 3 and 2 mol.L–1 at 600 nm. The picosecond pulse radiolysis measurements show that the radical of carbonate is formed through two ways: the direct effect by dose absorption by highly concentrated solute and by an ultra‐fast oxidation by H2O+.

21

Session 8

Experimental and theoretical perspectives of the effect of charge exchange of medium speed ions in various nuclear materials Jennifer Schofield1,2,3, Jay A. LaVerne3,4, & Simon M. Pimblott1,2

1The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, United Kingdom 2The University of Manchester, Dalton Cumbrian Facility, Westlakes Science and Technology Park, Moor Row, CA24 3HA, United Kingdom 3University of Notre Dame, Radiation Laboratory and Department of Physics, Notre Dame, IN 46556, USA 4University of Notre Dame, Department of Physics, Notre Dame, IN 46556, USA The interaction and energy loss of ions in a material can have a significant impact on the chemistry of the system. The method for energy loss calculation in this project uses a quadratic extension of the dipole oscillator strength distribution for a material in question. Charge exchange, the gain and loss of electrons by ions, plays a significant role in the energy transfer, and attenuation of, ions in materials, especially in the medium energy range of ions (around 1 MeV/amu). Most energy loss models approximate the charge of the incoming ion according to empirical data by an ‘effective charge’ [1, 2]. However this effective charge is no substitute for charge exchange data for specific ions when considering track structure chemistry. Detailed exchange cross-sections are required to understanding the effects of charged particle radiation on materials.

The results of experiments examining charge cycling in 4He2+ and 7Li3+ ions in Ti, Zr and Cu thin films will be presented. These studies were performed using the 10MV tandem ion accelerator at the NSL, University of Notre Dame, USA employing a method outlined previously [3]. Film materials were selected because of their ubiquitous application in the nuclear industry. Helium and Lithium ions were chosen, being the products of the B(n,a)Li reaction in coolant water. In addition, their generation is straightforward at energies where significant charge cycling processes were expected.

The data gained allows a better understanding of energy transfer of ions in materials and thereby sheds light on the deleterious effects of ionising radiation on material properties.

[1] T.E. Pierce, M. Blann, Stopping Powers and Ranges of 5-90 MeV S32, Cl35, Br79, and I127 Ions in H2, He, N2, Ar, and Kr: A Semiempirical Stopping Power Theory for Heavy Ions in Gases and Solids, Physical Review, 173 (1968) 390-405. [2] J.F. Ziegler, M.D. Ziegler, J.P. Biersack, SRIM – The stopping and range of ions in matter (2010), Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 268 (2010) 1818-1823. [3] C. Schmitt, J. LaVerne, D. Robertson, M. Bowers, W.T. Lu, P. Collon, Equilibrium mean charge states for low-Z ions at < 1 MeV/u in carbon, Phys Rev A, 80 (2009).

Acknowledgement: The research described was supported by the EPSRC Nuclear FiRST Doctoral Training Centre, by DCF programme, a joint initiative of The University of Manchester and the UK Nuclear Decommissioning Authority, and by the Office of Basic Energy Sciences of the US Department of Energy

22

Towards nanoparticle enhanced radiotherapy: A research programme towards better cancer care

Fred Currell1

1 Centre for Plasma Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, UK

Carefully designed nanoparticles containing heavy atoms have the potential to offer benefits normally only associated with heavy ion therapy but without the need for specialist ion accelerators. The vision for this kind of therapy is that is would be delivered at more traditional clinical centres such as those found in most industrial cities, using Linacs. This statement is supported by in-vivo measurements (e.g. [1]) and a nanodosimetric model [2]. However, more research is needed before the reality of such a vision can be properly assessed. In order to perform this assessment a combination of modelling and measurements are being performed. One model successfully connects the collective atomic physics events to the biological outcome through a local probabilistic interpretation of induction of lethality [2]. However there are still puzzles concerning the biological effects even in quite simple systems [3], some of which will be discussed. Furthermore, physical chemistry measurements hint at still further enhancements yet to be realised [4]. A model able to account for the observations in general terms will be introduced. A brief ‘future-look’ will show how the models of the relevant processes might be incorporated into the next generation of radiotherapy planning tools [5] as nanoparticles of this type begin to enter the clinic [6]. References: [1] S. Jain et al “Cell-Specific Radiosensitization by Gold Nanoparticles at Megavoltage Radiation Energies” Radiation Oncology Biology, 79 531-539 (2011) [2] S. McMahon et al “Biological consequences of nanoscale energy deposition near irradiated heavy atom nanoparticles” Nature Sci. Rep. 1:18; DOI:10.1038/srep00018 (2011) [3] S.McMahon, W.Hyland et al “Energy Dependence of Gold Nanoparticle Radiosensitization in Plasmid DNA” J.Phys.Chem.C 115: 20160–20167 DOI:10.1021/jp206854s (2012) [4] Sicard-Roselli C et al. „A New Mechanism for Hydroxyl Radical Production in Irradiated Nanoparticle Solutions” Small 10, 3338–3346, doi: 10.1002/smll.201400110 (2014) [5] “Improving patient outcome by integrating the generic with the personal” on line: http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef=EP/K039342/1 [6] http://www.nanobiotix.com/news/release/nanobiotix-presents-successful-phase-i-results-for-its-lead-nanomedicine-product-nbtxr3-at-asco/

23

Icarus, ArgoNeuT, and the search for Dark Matter. Applications of the recombination theory

Mariusz Wojcik

Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland

E-mail: mariusz.wojcik@p.lodz.pl

An interesting research area for radiation chemistry is the ionization-track processes observed in radiation detectors working for elementary particle physics, astrophysics, and cosmology. The most important detecting media for these devices are the liquefied rare gases, especially argon and xenon. Large, even tonne-scale noble liquid detectors are being constructed and operated within international collaborative projects. Despite the wide use of the noble liquid detectors, we still lack a good understanding of the fundamental track processes in these devices. One of such processes is the electron-ion recombination, which directly affects the main detector observables - the yield of collected charge and the scintillation yield. Because of the limitations of the current recombination theory, empirical models are in use that lack sufficient physical justification. In this talk, I will present analyses of the experimental data from the liquid argon ionization detectors based on the results of computer simulations of the electron-ion recombination process. The applied simulation methodology uses a realistic model of electron transport, which is based on the electron scattering cross sections for the energy range 0-100 eV. The applicability of the model was verified by the calculations of the recombination factor for the stopping proton tracks [1] that reproduced the experimental results obtained from the Icarus detector. Those calculations were followed by other applications of our simulation methodology. In collaboration with the ArgoNeuT group (FermiLab, USA), the dependence of the recombination factor on the angle between the track axis and the applied electric field was calculated and used to interpret their experimental data [2]. Probably the most attractive field for an application of the recombination theory is currently the search for Dark Matter. One possible method to prove the existence of Dark Matter is to observe the ionization tracks of nuclear recoils of the hypothetical WIMPs (weakly interacting massive particles). These recoils are expected to have energies in the lower keV range, and the estimated rate of their production is very low (less than 1 count/kg/year). Moreover, little is known so far about the energy deposition by the low-energy nuclear recoils and other fundamental processes in their tracks. I will present the results of simulation calculations of the electron recombination processes in the tracks of ~5 keV nuclear recoils in liquid argon. The calculations are carried out for different track models, cover a wide range of parameters, and involve an energy distribution of the secondary electrons. The results of the number of escaped electrons vs. the applied field strength are compared with the recent measurements of the nuclear recoils of keV neutrons in liquid argon [3]. The question of directional sensitivity of the nuclear recoils detection methods will also be discussed. This work was supported by the National Science Centre of Poland (Grant No. DEC-2013/09/B/ST4/02956). References [1] M. Jaskolski, M. Wojcik, J. Phys. Chem. A, 115, 4317 (2011). [2] R. Acciarri, et al., JINST, 8, P08005 (2013). [3] T.H. Joshi, et al., Phys. Rev. Lett. 112, 171303 (2014).

24

Session 9

Mechanistic studies on the role of [Cu(CO3)n]2-2n as a water oxidation catalyst

Israel Zilbermanna,b, Amir Mizrahia,b, Eric Maimona,b, Haim Cohenb,c, Haya Kornweitzc and Dan Meyersteinb,c a Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel b Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel c Biological Chemistry Department, Ariel University, Ariel, Israel

Recent interest in the field of water oxidation has triggered the discovery of a wide variety of catalytic systems, homogeneous and heterogeneous. Identification and direct observation of the key intermediates is vital for unraveling the mechanism of water oxidation in a particular system(1). Recently it was reported(2) that [Cu(CO3)n]2-2n acts as a electro-catalyst for the oxidation of water. The detailed mechanism was discussed but the question whether a CuIII or a CuIV intermediate is the key oxidizing agent was not elucidated. Pulse radiolysis is known as a mechanistic tool for elucidating the mechanisms of single-electron redox processes. Under the same conditions described in the electro-catalytic study2 pulse radiolysis measurements revealed that [CuIII(CO3)n]3-2n has a spectrum similar to that observed electrochemically. Furthermore the kinetics of disappearance of [CuIII(CO3)n]3-2n obey a second order rate law. DFT calculations reveal a significant charge transfer from the coordinated carbonate to Cu(III), suggesting that the coordinated carbonate has a radical character.

1. D. Polyansky; J. Hurst; S. Lymar. Eur. J. Inorg. Chem. 619–634 (2014). 2. Z. Chen; T. J. Meyer. Angewandte Chemie 52, 700-703 (2013).

25

Session 10

Radiolytic corrosion occurring at the solid/solution interface investigated at SUBATECH: example of Uranium and Titanium

J. Vandenborre(1), A. Traboulsi(1), M.Ghalei(1), S.Noirault(1), G. Blain(1), F. Haddad(2), M. Fattahi(1) (1)SUBATECH laboratory – 4, rue Alfred Kastler – La Chantrerie BP 20722, 44307 Nantes cedex 3 – France (2)ARRONAX cyclotron – 1, rue Arronax – CS 10112, 44817 Saint Herblain cedex – France

In this work, a new method was developed to achieve a global study of the radiolytic corrosion of a material by the 4He2+ radiolysis products of water. The originality of this work consists in developing a new in situ multi technical experimental device to exhaustively investigate the radiolytic corrosion of a material at the solid-liquid interface. The new developed device is to be installed in the irradiation room of a cyclotron facility whereas the scientific analyses of interest are deported and performed in another room. The new approach combines for the first time several spectroscopic and analytical techniques. It allows indeed to: 1) characterize the solid corrosion in situ, 2) quantify gases produced by water radiolysis after irradiation (to study their effect on the corrosion process) and 3) carry out an ex situ analysis of the irradiated solution to determine any soluble species formed by water radiolysis or released by corrosion of the corroded material. The new method described in this talk allows us to study simultaneously the effect of several parameters of interest (e.g. dose rate, absorbed dose, irradiation atmosphere…) on the corrosion process. It also permits to determine the dose rate delivered by the 4He2+ ion beam in situ and in a single irradiation experiment which is a new technique never used before. An interesting example, corrosion of UO2 by the oxidative species produced by 4He2+ radiolysis of water, was investigated in this work. Therefore, we investigated the radiolytic corrosion of UO2 by 4He2+ radiolysis of water at the solid-liquid interface 1 .The aim of this investigation was to determine the effect of certain parameters, which vary in realistic conditions, on the UO2 corrosion. Two interesting parameters were studied: the absorbed dose and the irradiation atmosphere. The originality of this work consists on investigating together the different faces of the chemistry under irradiation of the UO2-water interface by coupling for the first time (1) characterization of the secondary oxidized phases formed on the solid surface, (2) determination of the radiolytic yields of H2O2 and H2 produced by water radiolysis and (3) quantification of soluble uranium released into the solution by corrosion of the material. Irradiation was realized by the He2+ beam of the ARRONAX cyclotron with energy of 66.5 MeV and a dose rate of 4.4 kGy min-1. The dose rate was determined in situ (during irradiation) by Fricke dosimetry. The surface of the solid was characterized by Raman spectroscopy during and after irradiation in order to follow any temporal evolution of its corrosion/oxidation process. H2O2 and H2 were measured by UV-VIS spectrophotometry and micro Gas Chromatography (µ-GC) respectively. In conclusion, this work brings some light on the radiolytic corrosion of UO2 by investigating the different faces of its chemistry under irradiation. We identified indeed: (1) the secondary phase formed on the solid surface, (2) the H2 role as an inhibitor agent, (3) the oxidative role of H2O2 and (4) the quantity of U species released by corrosion of the material surface. Furthermore, detailed mechanisms of UO2 corrosion/oxidation will be proposed taking into account the phenomena of water radiolysis.

Another example of our activities is the study of radiolytic corrosion of Titanium and its alloys. The TA6V and T40 alloys are considered as good candidates materials for primary component circuit of mobile or stationary nuclear power plant owing to their advantageous combination of properties, i.e. low elasticity modulus, high resistance to impact loading, high strength, low density and low thermal expansion coefficient. α and γ irradiations has been performed on titanium alloys in water in the ARRONAX cyclotron (68 MeV) and γ irradiator (661 keV) up to a dose of 70 kGy at room temperature. This study describes water radiolysis effects on titanium alloys by measurement of radiolytic yield and structural studies (XRD, SEM and XPS). It also shows an in situ electrochemical study of alloys titanium behaviors (under α irradiation) with corrosion rate determination. Two different behaviors were observed, a decrease of corrosion rate for T40 (>200 nm/y for 40 kGy) and an increase for TA6V (up to 1.2µm/y for 25kGy).

1. Traboulsi, A.; Vandenborre, J.; Blain, G.; Humbert, B.; Barbet, J.; Fattahi, M., Radiolytic Corrosion of Uranium Dioxide: Role of Molecular Species. The Journal of Physical Chemistry C 2014, 118, (2), 1071-1080.

26

Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion-batteries

D. Ortiz1, S. Legand2, J.P. Baltaze,3 J-F Martin,4 J. Belloni,5 M. Mostafavi,5 and S. Le Caër1* 1 Institut Rayonnement Matière de Saclay, NIMBE, UMR 3685 CNRS/CEA, LIONS, Bâtiment 546 91191 Gif-sur-Yvette Cedex, France. 2 CEA/Saclay, DEN/DANS/DPC/SECR/LRMO 91191, Gif-sur-Yvette Cedex, France. 3 Laboratoire de Chimie-Physique, UMR 8000 CNRS Université Paris Sud, Faculté des Sciences, Bâtiment 349, 91405 Orsay Cedex, France. 4 CEA/LITEN/DEHT/SCGE, Grenoble, France. 5 Laboratoire de Chimie-Physique/ELYSE, UMR 8000 CNRS Université Paris Sud 11, Faculté des Sciences, 91405 Orsay Cedex, France. * sophie.le-caer@cea.fr

The ageing phenomena occurring in electrolytes are studied using radiolysis as a tool to generate the same species as the

ones in electrolysis. This approach entails indeed important benefits: (i) the time to degradate the electrolyte is shortened

as compared to electrolysis studies (hours instead of weeks or months), (ii) both short-time (ps-μs) and long-time

(minutes-days) processes can be studied, offering then an understanding on multiple temporal scales and (iii) the

possibility to study each solvent with/without the salt to understand its reactivity, which is not necessarily possible in a

real battery approach. The reaction mechanisms accounting for the degradation of electrolytes can then be proposed.

Finally, in order to demonstrate the utility of the approach, the radiolytic results are compared with classical

charge/discharge experiments. This comparison illustrates the interest of the radiolysis approach.

27

Overview of properties affecting release of radionuclides from spent nuclear fuel under long-

term storage conditions

Olivia Roth Studsvik Nuclear AB, SE-611 82 Nyköping, SWEDEN The waste generated by the nuclear power industry can be divided into three groups; operational waste, decommissioning waste and spent nuclear fuel. Operational waste and decommissioning waste constitute by far the largest quantity of the waste, whereas the spent nuclear fuel is the most hazardous part due to its high level of radioactivity. Spent fuel must be radiation-shielded and cooled throughout handling, transportation and storage and isolated for at least 100,000 years. Most of the spent nuclear fuel that exists today are destined for long-term storage and eventual geologic disposal. Today, the spent nuclear fuel is stored either in pools or dry casks at reactor sites. Most nuclear fuels are based on UO2. During in-reaction irradiation the composition of the fuel changes due to fission processes, neutron capture and subsequent decay of the produced radionuclides. The global inventory of radionuclides in the used fuel depends on factors such as the initial enrichment and fuel burn up. The distribution of the radionuclides in the fuel depends on factors such as neutron flux gradients, thermal gradients, chemical reactions and properties of the produced elements and as a result of these processes spent nuclear fuel is a highly inhomogeneous, quite complex material. The inhomogeneity and complexity of the spent fuel complicates the assessment of radionuclide release from the spent fuel under storage conditions (e.g. the release of radionuclides from spent fuel in contact with water) as the mechanism and rate of dissolution will vary between different elements. For example, some elements such as cesium and iodine are known to be released rapidly when the fuel comes in contact with water whereas other elements such as lanthanides and actinides are release at a slower rate. The rational for this behavior is that cesium and iodine prevail in gaseous phase at reactor temperature and during operation migrate to the gap between the fuel and the cladding and to grain boundaries that are easily accessible to the water. Lanthanides and actinides are distributed in the UO2 matrix and the release is controlled by the matrix dissolution rate. When assessing the behavior of spent nuclear fuel under storage conditions, knowledge and understanding of the spent fuel properties are key to understanding the radionuclide release. Furthermore, in order to enable predictions of radionuclide release rates, links between easily accessible data such as fission gas release or reactor operation parameters also need to be established. This presentation will give an overview and examples of fuel properties that can be linked to radionuclide release behavior.

28

Session 11

Transport of Charge Carriers in DNA-based Systems beyond One Dimension: Charge Flow

across Practically Important Molecular Construct with Complex Architecture

Yuri A. Berlin Northwestern University, Department of Chemistry, Evanston, IL 60208-3113, USA According to current consensus (see e.g. reviews 1-4), charge can effectively move within the double stranded DNA along the one-dimensional (1-D) pathway provided by the stack of base pairs. For rationally designed sequences of such pairs, this allows double helix to be considered as a potential linear connector in molecular electronic circuits. However DNA-based molecular electronics also requires charges to be transported from one site to another within a 2D- or 3D-architectures serving as molecular switches or other higher circuit elements. DNA three-way junctions (TWJs), for example, are of potential use in this context as charge splitters or combiners. In this contribution the result of theoretical modeling of CT in DNA beyond one dimension are reported. Using molecular dynamics simulations and quantum calculations, DNA-based TWJs were found to undergo dynamic interconversion among “well stacked” conformations on the time scale of nanoseconds, a feature that makes the junctions very different from linear DNA duplexes. Based on the simulations performed, it can be expected that CT in DNA-based TWJs studied is gated by conformational fluctuations and that DNA-based TWJ CT devices should be within reach. Moreover, it may be possible to use external fields to future control the conformational changes of DNA-based TWJs, thus attaining fully gated DNA CT. If so, field-effect transistors (FETs) based upon TWJs could become accessible.

References 1. Bixon, M.; Jourtner, J. Chem. Phys. 2002, 281, 393 – 408. 2. Schuster, G. B. Long-Range Charge Transfer in DNA, Topics in Current Chemistry, 2004, vols. 236 and 237. 3. Berlin, Y. A.; Kurnikov. I. V.; Beratan, D.; Ratner, M. A.; Burin, A. L. Topics in Current Chemistry 2004, 237, 1-

36. 4. Berlin, Y. A.; Ratner M. A. Charge Migration in DNA. Perspectives from Physics, Chemistry, and Biology,

Chakraborty, T (Ed.); Springer: Berlin, 2008, pp 45-62

29

Dissociative electron attachment to isotopic and isomeric gas-phase molecules

Sylwia Ptasinska Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA

The high energy quanta of impinging radiation can generate a large number (about 5x104) of secondary electrons per 1 MeV of energy deposited. When ejected in condensed phase water, the kinetic energy distribution of these free or quasi-free electrons is peaked below 10 eV. Low energy electrons also dominate in the secondary emission from biomolecular targets exposed to different energies of primary radiation. Due to the complexity of the radiation-induced processes in the condensed-phase environment, mechanisms of secondary electrons induced damage in biomolecules (BM) still need to be investigated. However, based on results from theory and different experiments accumulated within the last decade, it is now possible to determine the fundamental mechanisms that are involved in many chemical reactions induced in isolated gas-phase biomolecules by low energy electrons. The central finding of earlier research was the discovery of the bond- and site- selectivity in the dissociative electron attachment (DEA) process to biomolecules. It has been demonstrated that by tuning the energy of the incoming electron we can gain control over the location of the bond cleavage. These studies with isotopically labelled molecules showed the selectivity in single bond cleavage reactions leading to the formation of the dehydrogenated closed shell anion (BM-H)- or the complementary reaction leading to H-. Moreover, the presence of tautomers can be detected by probing a molecular beam with low energy electrons, which showed different reactivity due to dipole moment of molecules. Our experimental findings were supported by quantum chemical computations.

30

Session 12

The ebeam Vitrine: the latest collection of ebeaming hardware

Ian Bland

ebeam Technologies, Switzerland

45 years ago, Silicon Valley and the semiconductor industry started a society-changing revolution with the introduction of the first single-chip CPU. This enabled the exponential explosion in computing power and the astonishing evolution from mainframe to minicomputer to PC to Laptop and now, the smartphone. COMET ebeam Technologies has recently made just such a quantum leap. Together with Tetra Pak, they have developed the world's first industrialized, compact "ebeam Lamp" and thus, electron beam equipment has successfully made the jump from "mainframe" to "mini". Within the next 7 – 10 years, more electron beam accelerators will be installed than have been in the entire history of electron beam accelerators.

This presentation will give an overview of: a) the hardware that is now available, b) what it means for science and society, as well as c) ebeam Technologies’ program for supporting research institutes and universities.

Do proteins protect DNA from radiation damage? Elspeth F. Garman1, Charles Bury1, Ian Carmichael2, John E. McGeehan3 1Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU 2Notre Dame Radiation Laboratory, University of Notre Dame, Indiana, IN 46556 USA 3Biophysics Laboratories, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, King Henry I Street, Portsmouth, Hampshire PO1 2DY, UK Email corresponding author: elspeth.garman@bioch.ox.ac.uk Significant progress has been made in molecular crystallography over recent years in both the understanding and mitigation of X-ray induced radiation damage when collecting diffraction data from crystalline proteins. In contrast, despite the large field that is productively engaged in the study of radiation chemistry of nucleic acids, particularly of DNA, there are currently very few X-ray crystallographic studies on radiation damage mechanisms in nucleic acids. However, there seems to be a perception that the latter is the more radiation susceptible. Quantitative comparison of damage to protein and DNA crystals separately is challenging, but many of the issues are circumvented by studying pre-formed biological nucleoprotein complexes where direct evaluation of damage to each component can be made under the same controlled conditions. Here we employ a model protein-DNA complex C.Esp1396I [1], to investigate specific damage mechanisms for protein and DNA in a biologically relevant complex over a large dose range (2.07 – 44.6 MGy). In order to allow a quantitative analysis of radiation damage sites from complex series of macromolecular diffraction data, we have developed a computational method that is generally applicable to the field. Typical patterns of specific damage we observed for both the protein, on particular amino acids, and for the DNA on, for example, the cleavage of base-sugar N1-C and sugar-phosphate C-O bonds. Strikingly, the DNA component was determined to be far more resistant to specific damage than the protein for the investigated dose range. At low doses the protein was observed to be susceptible to radiation damage while the DNA was less affected, damage only being observed at significantly higher doses [2]. References [1] McGeehan, J.E., Streeter, S.D., Thresh, S.J., Ball, N., Ravelli, R.B.G. & Kneale, G. (2008). Nucleic Acids Res. 36, 4778-4787 [2] Bury C. Garman, E.F., Ginn, H.M., Ravelli, R.B.G., Carmichael, I., Kneale, G. & McGeehan, J.E. (2015)

J. Synchrotron Radiat. 22, in press

31

Picosecond and Nanosecond Pulse Radiolysis of Melts of Lithium-Potassium Chloride Shinichi YAMASHITA,1,* Yuki MAEHASHI,1 Yusa MUROYA,2 Yosuke KATSUMURA1 1: School of Engineering, the University of Tokyo, 2: The Institute of Scientific and Industrial Research, Osaka University. * Corresponding author’s e-mail: shin1@nuclear.jp Melts (molten salt), which is liquid salt at elevated temperature and composed of dissociated cations and anions, is expected as a coolant in one of Gen IV reactors, molten salt reactor (MSR), as well as a solvent in pyroprocessing of spent fuels, electrolysis. In these applications, molten salt is used under strong radiation fields, and thus, radiation effects on molten salt are of crucial importance. Radiolytic products might induce or accelerate corrosion of structural materials. Accumulation of stable radiolysis products might change electrochemical property of molten salt, which would lead to decrease of separation efficiency in electrolysis. In this study, we purposed to investigate radiation-induced chemical reactions in molten salts by using a pulse radiolysis technique. Picosecond pulse radiolysis was performed at the LINAC facility in Tokai-mura campus, the University of Tokyo, Japan. Crystalline anhydrous beads of eutectic salt of lithium-potassium chloride (58:42 in mol ratio, > 99.99%) were put into cuvettes of suprasil quartz. Crystalline anhydrous beads of lithium chloride or those of potassium chloride (> 99.999%) were added to obtain different composition ratio. The samples were connected to a vacuum line and heated to remove water and air. One of the samples was put in a heater made of Inconel®, which was placed at an irradiation port of LINAC. The heater has sapphire and quarts windows for the analyzing light and can be used at the temperature up to 700○C. Two peaks were found in UV and Vis-IR regions of transient absorption spectra, which are attributed to hole-like radicals such as Cl2

•−/Cl• and solvated electron, e−sol, respectively. The peak of e−

sol showed red shift with increasing temperature or with increasing ratio of K+ to Li+. The peak shift due to the change of the composition indicated a shallower solvation potential for K+-rich molten salt resulted from larger ionic radius of K+ than Li+. This tendency agrees well with peak position of F centers in alkali chloride crystals. Initial yield of Cl2

•− was evaluated from the peak height and molar absorption coefficient in water (7700 M−1cm−1 at 380 nm) to be 4.4 (100 eV) −1. Assuming that this value is the same as initial yield of e−

sol, its molar absorption coefficient was estimated to be approximately 18000 M−1cm−1, which is quite close to the value of e−

sol in water at room temperature. Within a few nanoseconds, the two peaks corresponding to e−aq and Cl2

•− showed almost the same decay kinetics, indicating a reaction e−

aq + Cl2•− → 2Cl−. Spur diffusion model simulation was also carried out,

leading to good reproduction of experimental results for wide time scale from picosecond to microsecond.

32

Session 13

Track-etched polymer membranes for research and applications M-C Clochard Laboratoire des Solides Irradiés, UMR 7642 Ecole Polytechnique/CEA/CNRS Université Paris-Saclay, F-91128 Palaiseau, France In collaboration with the CIMAP (GANIL, France), the XPnano group at the LSI (Ecole Polytechnique, France) synthesizes nanoporous polymer membranes using ion track technology. In numerous polymers, the zone of defects close to the ion trajectory, called the latent track, is rich in radicals and it can be directly modified chemically by radio-induced grafting. Grafted cylindrical channels are then formed inside a polymer matrix. Latent tracks may also be etched by chemical attack. Cylindrical pores are then obtained that are parallel one to

another, and have mono-disperse radii in the range between 10 nm and microns depending on the etching conditions and the nature of the ion-projectile (Fig.1). Also other geometries are designed, like conical shapes in well-chosen polymers, which permit to decrease the aperture to only a few nm. Figure 1 : PVDF track-etched membrane with

pore radius of 10 nm (A) and of 150nm (B). The persistence of radicals after etching in a fluoropolymer membrane has been proven in our group by EPR. The subsequent radio-grafting has been localized by Confocal Laser Scanning Microcoscopy (Fig. 2) for diameters inferior to 100 nm. This property allows us to radiograft, very locally, a hydrophilic polymer in a hydrophobic matrix starting from the walls of the nanopores. A specific functionalization inside the nanopores becomes then possible. Figure 2: CLSM image of the cross-section of a radiografted track-etched membrane Using “living” controlled radical polymerization (RAFT mechanism), these nanopores can be tuned very accurately by monitoring the nanometric coverage of their walls. This way one can follow how the pores are filled progressively by the growing grafted polymer chains until the complete the blockage of the pores and beyond that stage while they spill in the form of protusions at the membrane surface.

33

Ion-track grafting has allowed the fabrication of many devices within our group. A number of salient results have been obtained in proton-conductive membrane fuel cells (automotive application) and in water quality sensors for the measurement of toxic metal ions at the trace level (sub ppb sensoring). These track-etched membranes are also routinely used as templates to grow metallic nanowires (NWs) inside the etched tracks. This opens the field of research on composite membranes with embedded magnetic NWs. Interesting behaviour of the Ni NW anisotropic magnetoresistance has been registered when biconical NWs are contacted. An experimental set-up at LSI allows contacting a single NW. Recent results obtained from such a set-up based on electroactive polymers like piezoelectric b-PVDF have shown how mechanical stress is apt to induce a giant magnetostrictive effect within a single Ni NW.

34

Radiation-synthesized hydrogel-based matrices for cell cultivation

Slawomir Kadlubowski, Justyna Komasa, Agnieszka Adamus, Piotr Ulanski, Janusz M. Rosiak Lodz University of Technology, Institute of Applied Radiation Chemistry, Wroblewskiego 15, 93-590 Lodz, Poland

Cellular environment is complex and plays an important role in cellular properties and processes. Interactions between cells and supporting matrix are an integral part of in vitro cell studies and influence cell adhesion, proliferation, gene expression and stem cells differentiation. In an attempt to replace biological matrices, numerous artificial, synthetic and organic, materials have been studied as potential cell scaffolds.

It has been shown in many studies that hydrogels provide an optimal substrate for the growth of various types of cells like chondrocytes, muscle cells of the veins, osteoblasts, fibroblasts or neurons. These studies indicated that hydrogels can act as extracellular matrix (extracellular part of animal tissue that provides structural support to the animal cells) for maintaining stable environment, supporting transport functions and providing a mechanical barrier against external stresses or disruptions.

In this work permanent hydrogels of various physical forms and chemical compositions were obtained by radiation technique. Radiation induced grafting and cross-linking polymerization provides unique possibility of synthesizing gels with no initiators, catalysts, etc., which are difficult to remove from the product and may induce cytotoxicity. Moreover, it allows for precise control of the thickness of grafted polymer layer, (nano)pore size and swelling ability. Two types of the product have been synthesized and tested:

- thermocontrolled scaffolds intended for skin and epithelial cell sheet cultures obtained by grafting of poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA) onto polypropylene dishes. Influence of monomer concentration and reaction time on grafting percentage were studied. Obtained products were analyzed by FT-IR, gravimetric and contact angle measurements. Results indicate that radiation-grafted POEGMA forms thermo-responsive layers on polypropylene films. Obtained products have been subjected to biological tests in fibroblast cultures – cell sheets were successfully detached by change of environment temperature.

- microporous polycationic gels of moderate charge density, obtained by irradiation of a monomer mixture containing 2-hydroxyethyl methacrylate, [2-(methacryloyloxy)-ethyl] trimethylammonium chloride and (poly(ethylene glycol) diacrylate as a support for 3D neuronal cells cultivation. Parameters describing network formation, i.e., gel fraction as a function of dose rate, gelation dose and degradation-to-cross-linking ratio for hydrogels of various compositions have been calculated. On selected matrices cell cultures have been cultivated showing the possibility to differentiate steam cells into neurons. Electric stimulation of neurons network induces the development of synapses between co-activated cells. In this way the synaptic network that is formed is specific to the stimulus and its topology consists the “memory” of the system.

This work was supported by the National Centre for Research and Development, Project POLYCELL PBS1/B9/10/2012

35

ABSTRACTS of

ORAL PRESENTATIONS of

YOUNG SCIENTIST AWARDEES

(in order of presentation)

36

Hydrogen peroxide formation during radiolysis of organic compounds Erzsébet Illés, Erzsébet Takács, László Wojnárovits Radiation Chemistry Department, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly Thege M. út 29-33, Budapest, H-1121 Large number of papers are published on the ionizing radiation induced degradation of organic pollutants in aqueous solutions. However, in radiolytic processes in water hydrogen peroxide is always produced, its effect in the degradation mechanism is usually neglected. Only few publications mention H2O2 formation and their possible role in the degradation mechanism (Liu et al., 2014; Szabó et al., 2014). It is important because of the economy of the treatment, moreover, the remaining H2O2 may have ecotoxic effect. Phenantroline/Cu2+ spectrophotometric technique was used for determination of H2O2 (Kosaka et al., 1998) and measure the kinetic curves of H2O2 concentration in irradiated solutions of several organic contaminants. The organic compounds (phenol, salicylic acid, orto-, meta- and para-krezol) were irradiated in 1 × 10−4 mol dm−3 aerated solutions, at room temperature with a dose rate of 10 kGy h−1, in open ampoules with air bubbling. In dilute aerated aqueous solutions H2O2 forms with a tolerably high initial yield of ∼2.5 × 10−7 mol J−1. The H2O2 concentration in the solution after a first fast rise tends to level off at constant value around 3 × 10−4 mol dm−3 showing equilibrium between formation and decomposition. The main source of H2O2 is the termination reaction of the O2

−•/HO2•

pair. The latter radicals mainly form in the eaq− + O2 reaction, but the H• + O2 reaction and HO2

• elimination from aromatic radicals also contributes O2

−•/HO2• and thereby to H2O2 production. Some H2O2 also forms in spur reactions. As

we suggest H2O2 is mainly consumed in the eaq− + H2O2 reaction.

Kosaka K, Yamada H, Matsui S, Echigo S, Shishida K. Comparison among the methods for hydrogen peroxide measurements to evaluate advanced oxidation processes: application of a spectrophotometric method using copper(II) ion and 2,9-dimethyl-1,10-phenanthroline. Environ. Sci. Technol. 1998;32:3821-3824.

Liu Y, Hu J, Wang J. Fe2+ enhancing sulfamethazine degradation in aqueous solution by gamma irradiation. Radiat. Phys. Chem. 2014;96:81-87.

Szabó L, Tóth T, Homlok R, Rácz G, Takács E, Wojnárovits L. Hydroxyl radical induced degradation of salicylates in aerated aqueous solution. Radiat. Phys. Chem. 2014;97:239-245.

37

Radiolytic method as a novel approach for synthesis of nanostructured conducting polypyrrole Zhenpeng Cui1, Cecilia Coletta1 and Samy Remita 1,2 1Laboratoire de Chimie Physique, LCP, UMR 8000, CNRS, Université Paris-Sud 11, Bât. 349, Campus d’Orsay, 15 avenue Jean Perrin, 91405, France 2Département CASER, Ecole SITI, conservatoire National des Arts et Métiers, CNAM, 292 rue Saint-Martin, 75141, France Key words: Radiolysis, Conducting polymers, Polypyrrole, Nanostructures Conducting polymers (CPs) have been intensively investigated due to their intrinsically π-conjugated systems _ENREF_1which enable their potential applications in various fields. We recently developed an alternative way to synthesize poly(3,4-dioxythiophene) PEDOT in aqueous solution: radiation-induced oxidation of EDOT monomers under “soft” conditions. [1] In the present work, we extend this radiolytic method to synthesize polypyrrole (PPy) and use chemical-induced polymerization for comparison purpose. The results demonstrate that spherical and chaplet-like PPy nanostructures are formed by γ-radiolysis. The radiosynthesized PPy have good thermal stability and an electrical conductivity higher than that of chemically synthesized PPy. [2]

[1] Lattach, Y.; Coletta, C.; Ghosh, S.; Remita, S.; ChemPhysChem, 2014, 15, 208-218. [2] Cui, Z.P.; Coletta, C.; Dazzi, A.; Lefrançois, P.; Gervais, M.; Néron, S.; Remita, S.; Langmuir, 2014, 30 (46), 14086–14094.

Fig 1. PPy synthesized by radiolytic method and in-situ observation of its morphology

38

Radiation-induced radical processes involving amino acids and quinoxalin-2-one derivatives. K. Skotnicki1, K. Bobrowski1, J. De la Fuente2, A. Cañete3

1Institute of Nuclear Chemistry and Technology, Warsaw, Poland 2Universidad de Chile, Santiago de Chile, Chile 3Pontificia Universidad Católica de Chile, Chile Substituted quinoxalin-2-ones (Chart 1) are considered to be used as potential anticancer, antimicrobial, antifungal and analgesic drugs.[1] Moreover, they inhibit activity of HIV enzymes. Molecular Dynamics simulations indicate that the pocket which could bind this class of compounds is located close to the ATP binding site, which may have serious consequences in their interactions with electron donor amino acids residues. Some of drugs based on the quinoxalin-2-one structure are in medical use, e.g. caroverine-based Spasmium. Its activity is connected to calcium-channel blocking and it is used as antispasmodic agent. Studies indicate that caroverine is a potential antioxidant agent, which acts in concentration possible to achieve and to be safe in a human body. [2] In spite of that fact one cannot find many publications concerning transformations of quinoxalin-2-one based compounds in biological systems.

Chart 1. Structural formula of quinoxalin-2-one

Radiolyticaly generated radicals and radical anions derived from amino acids can possess both oxidizing (i.e. tyrosyl radicals) and reductive (i.e. alfa-amino radicals generated after decarboxylation) properties. They are formed in organisms during oxidative stress which leads to production of ROS and RNS. Reactive radicals derived from amino acids emerging from these processes are supposed to react with quinoxalin-2-ones resulting in formation of transient and stable products. The aim of this study was to characterize quinoxalin-2-ones one-electron oxidation and reduction processes and to elucidate their interactions with amino acids, which may occur in organism. 3-methylquinoxalin-2-one has been reduced by solvated electron and oxidized by wide range of one-electron oxidants with different redox potentials. What is more, selected amino acids has been used to generate radical species in the presence of 3-methylquinoxalin-2-one and all arising (possible to detect) products has been followed. Respective second-order rate constants for each amino acid related radicals has been calculated. Nanosecond pulse radiolysis technique (based on a linear electron accelerator) combined with spectrophotometric UV-VIS detection has been applied to perform experiments. 1. Carta, A., et al., Chemistry, biological properties and SAR analysis of quinoxalinones. Mini-Reviews in

Medicinal Chemistry, 2006. 6(11): p. 1179-1200. 2. Udilova, N., et al., The antioxidant activity of caroverine. Biochemical Pharmacology, 2003. 65(1): p. 59-65.

39

Pairing of Solvated Electron with Monovalent Cation in Aqueous and Tetrahydrofuran

Solutions Studied by Picosecond Pulse Radiolysis

Jun Ma, Pierre Archirel, Pascal Pernot, Uli Schmidhammer, and Mehran Mostafavi Laboratoire de Chimie Physique/ELYSE, CNRS/Université Paris-Sud, Faculté des Sciences d’Orsay, Bât. 349, 91405 Orsay Cedex, France. E-mail: jun.ma@u-psud.fr The reaction of hydronium ion (H3O+) with hydrated electron in aqueous solutions has been of continuing interest in radiation chemistry. Due to the rearrangement of surrounding water molecules, the reaction rate constant of this process is not controlled by diffusion. The presence of a reaction barrier suggests the formation of a transient pair before yielding the H atom. At room temperature, the picosecond pulse radiolysis in concentrated acidic aqueous solutions shows the time-resolved absorption spectra of hydrated electron undergoes a blue shift, while keeping the similar spectra band with increasing the concentration. The lowest concentration that could induce this shift starts from 0.5 mol L-1. This observation presents a direct evidence for transient pair formation between H3O+ and with hydrated electron. However, in very non-polar solvent Tetrahydrofuran (THF), the presence of perchlorate acid molecule has no effect on the absorption spectra band of solvated electron with the maxima at 2200 nm, indicating this reaction in THF is completely different from that in water. In addition, lithium metal cation was further selected to pair the electron in the time scale of picosecond. The main peak is blue shifted, yet the optical absorption spectrum of (es¯, LiClO4)s consist of two bands at 1200 nm and 950 nm; which is not consistent with results obtained by the nanosecond pulse. The theoretical study on the assignments of the observed peaks in terms of several absorbing “ion pair” is in progress.

Fig.1 A spectral blue shift of hydrated electron in presence of hydronium ion.

40

Multigenerational Effects of Radium-226 in Mammals

S. Walsh, M. Satkunam, B. Su, A. Festarini, M. Bugden, H. Peery, M. Stuart

Environmental Technologies Branch, Canadian Nuclear Laboratories, Chalk River, Ontario, Canada, K0J 1J0

The Canadian Nuclear Safety Commission recognized the need for more data on the multigenerational effects of chronic exposure to low levels of alpha-emitting radionuclides on health and reproductive fitness of animals, including mammals. To address this data gap, a study consisting of a control group and four treatment groups each containing 40 mice (20 males and 20 females) of the CBA/CaJ strain that were continuously exposed to 0.012, 0.076, 0.78 and 8.0 Bq/L of Ra-226 via drinking water was conducted at Canadian Nuclear Laboratories. Breeding was at 8 weeks of age and the study was concluded after 3 breeding cycles. Breeding success, number of pups per litter, growth and health of pups were not negatively affected by their own, their parents’ and grandparents’ constant (including in utero) exposure to low levels of Ra-226 compared to the corresponding control mice. Tissues collected during the study are currently being used to obtain dosimetric data and to measure a number of cellular and molecular biological markers of radiation exposure and effects. This data will be used to inform environmental regulations for uranium mines. Very high yields of the hydroxyl radical in gold nanoparticle-doped water C. Polin, N.Wardlow and F.J. Currell Centre for Plasma Physics, School of Maths and Physics, Queen’s University, Belfast, BT7 1NN, UK Recent results we obtained irradiating colloidal gold at the Diamond light source [1] will be reviewed with the benefits of using synchrotron radiation for such studies being highlighted. The first quantified evidence for a new mechanism of potential importance to cancer therapy, nuclear waste handling, radiation chemistry and catalysis will be presented. These results suggest a pathway, whereby energy deposited in the medium transports to the water-nanoparticle interface can dominate the formation of hydroxyl radicals (OH). This result is key to the idea of nanoparticle-assisted radiotherapy since OH is the species responsible for the majority of DNA damage in traditional radiotherapy. New, unpublished, measurements will be presented concerning the size-dependence of the G-value for OH formation. These data give further evidence for the diffusion-to-nanoparticle hypothesis. With another beam time at Diamond scheduled for two weeks before the conference and our in-house radiation research platform coming on line (see poster by C. Figuera et al elsewhere at this meeting) we hope to be able to provide further insight into the mechanism at work. [1] Sicard-Roselli C et al. “A New Mechanism for Hydroxyl Radical Production in Irradiated Nanoparticle Solutions” Small 10, 3338–3346, doi: 10.1002/smll.201400110 (2014)

41

Hydrogen generation from irradiated aluminum hydroxydes and oxyhydroxydes J.A Kaddissy1, S. Esnouf2, F.Cochin3, T.Fares3*, D. Saffré4, J.P Renault1 1 CEA/DSM/IRAMIS/NIMBE/LIONS – CEA Saclay – 91191 Gif Sur Yvette Cedex, France 2 CEA/DEN/DANS/DPC/SECR/LRMO– CEA Saclay – 91191 Gif Sur Yvette Cedex, France 3 AREVA NC DOR/RDP – 1 place de la Coupole, 92084 La Défense, France 4AREVA TN– 1 rue des Hérons, 78180 Montigny Le Bretonneux Transportation is a critical issue for the current management of nuclear wastes. One potential source of hydrogen generation is the radiolysis of hydrated mineral phases encountered in the nuclear waste transportation and storage casks. Determining the mechanisms of dihydrogen formation that may occur in the hydroxide or oxyhydroxide and generalise it to other hydrates is of particular interest for safety concerns. We chose to study aluminum hydroxide (Al(OH)3) (Bayerite) and oxyhydroxides (AlOOH) (Boehmite) as model compounds To our knowledge similar results have not been reported unless recently by Westbrook et al. [1]

On the first hand, we quantified the yield of H2 generated from gamma and electron-irradiated samples. On the other, in order to have a better understanding of the mechanisms we studied the irradiation defects, the formation and trapping of H• radicals using Electron Paramagnetic Resonance (EPR). The samples were irradiated either at room temperature or at 77K in order to trap the defects. Minor values of hydrogen released from dried samples were detected. Once the samples were hydrated, hydrogen yield significantly increased and had a greater value in the case of Boehmite AlO(OH). As no correlation was observed between G(H•) and G(H2), we can either suppose that trapped H• is not the only precursor of H2 or this latter stays trapped in the bulk. Our results will be presented and discussed considering previous studies[1-

4_ENREF_1_ENREF_1_ENREF_1_ENREF_1_ENREF_1_ENREF_1]. Experiments of Electron Paramagnetic Resonance (EPR) performed immediately after irradiation at room temperature revealed that a significant amount of H• remained trapped in the Boehmite crystallites (Figure 1). The trapping efficiency and detrapping kinetics as a function of crystallite size, structure, time and temperature were analyzed. Radiation induced defects were also formed, some appeared after low doses others were more stable at higher ones such as O•- (Figure1).

Figure 1 Effect of the dose on Radiation induced defects generated from wet electron-irradiated Bayerite (At room temperature)

1. Westbrook, M. L.; Sindelar, R. L.; Fisher, D. L., Radiolytic hydrogen generation from aluminum oxyhydroxide solids: theory and experiment. J Radioanal Nucl Chem 2015, 303, (1), 81-86. 2. LaVerne, J. A.; Tandon, L., H2 Production in the Radiolysis of Water on UO2 and Other Oxides. The Journal of Physical Chemistry B 2003, 107, (49), 13623-13628. 3. Barsova, L. I.; Yurik, T. K.; Spitsyn, V. I., Radiation centers in alkaline-earth hydroxides. Journal Name: Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl. Transl.); (United States); Journal Volume: 35:5; Other Information: Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya; 35: No.5, 969-974(May 1986) 1986, 879-883. 4. Steinike, U.; Barsova, L. I.; Jurik, T. K.; Kretchmar, U.; Hennig, H. P.; Bol'mann, U., Nature of mechanically induced defects in polycrystalline hydrargillite and Al2O3-A1(OH)3 studied by radiation methods. Bulletin of the Academy of Sciences of the USSR, Division of chemical science 1990, 39, (7), 1321-1324.

3200 3400 3600 3800 380 360 340

II F center

I Oo-

Magnetic field (mT)

Dose 5-245 kGy

Ho-

320

42

Modeling Interfacial Radiation Chemistry Björn Dahlgren1, Mats Jonsson1 1School of Chemical Science and Engineering, Applied Physical Chemistry, KTH, Royal Institute of Technology Interfacial radiation chemistry has received considerable attention lately. Strongly modified radiolytic yields have been reported for several different kinds of systems. Currently, different models are needed for different materials (e.g. exciton transport in semiconductors).

Ideally, these models would be put in a framework already considering the common aspects of interfacial (water) radiolysis. Working towards this goal, we make a first refinement of the currently well establish deterministic modeling of the chemical stage by employing the Schmoluchowski equation (considering diffusion, reactions and electrostatically induced drift). The Schmoluchowski equation is derived for flat, cylindrical and spherical geometry, discretized in one dimension (assuming isotropy). The spatial derivatives are estimated by finite differences on an arbitrarily spaced grid with an arbitrary (odd) number of stencil points. The system may be solved with isolating or extrapolating boundary conditions. Expressions for the logarithmically transformed system (any combination of concentration, time, space) have also been derived and may be integrated instead of the stiffer untransformed system of ODEs.

The model is then used to investigate the effect of incident radiation with strongly varying LET, where – as a first approximation – the local radiolytic yields are assumed to be the same as for the corresponding bulk value. The spatial profile of the dose rate can be taken from linear attenuation (γ-rays) or generated from state-of-the-art electron/transport transport models.

The performance of the model is evaluated against experimental data. And we will discuss the impact of the level of detail in the dose rate profile, and how charge separation processes may be accounted for. The performance and accuracy of the PDE solver for different setups of the integration will also be presented.

43

Investigation into the Radiolysis of PUREX Solvent Systems

Gregory P. Hornea,b, Howard E. Simsa,d, Robin Taylora,c, Simon M. Pimblotta,b

aThe University of Manchester, Dalton Cumbrian Facility, Westlakes Science and Technology Park, Cumbria, CA24 3HA, UK bThe University of Manchester, School of Chemistry, Oxford Road, Manchester M13 9PL, UK cNational Nuclear Laboratory, Central Laboratory, Sellafield, Cumbria, CA20 1PG, UK dNational Nuclear Laboratory, Building 168, Harwell Business Centre, Didcot, Oxon, OX11 0QT, UK

Plutonium Uranium Reduction EXtraction technology is a solvent extraction process used to recover potential energy content, in the form of plutonium and uranium, from spent nuclear fuel. The PUREX solvent system is composed of an aqueous nitric acid phase in contact with an organic phase, comprising ~30 vol % tributyl phosphate in an organic diluent. Due to its radioactive content, the PUREX process is subject to an intense multicomponent radiation field (γ-rays, α-particles, β-particles etc.) rendering the solvent system susceptible to radiolytic degradation, generating vast numbers of degradation products. Consequently, the formulation of the PUREX solvent is altered, potentially affecting its redox and physicochemical properties, extraction affinities, and kinetics. It is these finely tuned properties that allow the PUREX process to function. Despite this, and having the PUREX process being used for over sixty years, a complete fundamental understanding of the radiolytic degradation has not been presented. This research bridges the outlined knowledge gap by establishing a much needed fundamental radiation chemical foundation for the radiolytic behaviour of the PUREX solvent system, with respect to the yields of nitrite and nitrous acid. Both nitrite and nitrous acid are redox active species, capable of altering the formulation of the PUREX solvent system (e.g. denitrification, deacidification, and nitration). They have also been shown to interact with a number of important metal cations (e.g. uranium, plutonium, and neptunium), disrupting their extraction properties through the formation of unfavourable complexes and oxidation states. As a consequence, it is important to understand the radiolytic yields of nitrite and nitrous acid, their associated radiation chemistry, and their interactions with other solvent system components. The presented research outlines the radiolytic yields of nitrite and nitrous acid measured as a function of solvent system formulation, dose (100 Gy to 1000 Gy), and radiation quality. Additionally, Monte Carlo and FACSIMILE modelling techniques have been used to interpret the data and explain the intricate radiation chemistry mechanisms. The radiolytic yields of nitrite and nitrous acid have been established using Co-60 γ-rays and α-particles, from the self-radiolysis of MAGNOX plutonium and ESA americium solutions, for aerated solvent systems of sodium nitrate and nitric acid (0.001 mol dm-3 to 6 mol dm-3). This research has been funded by the EPSRC, SACSESS, and the Dalton Cumbrian Facility, a joint initiative of the NDA and the University of Manchester.

44

ABSTRACTS of

POSTER PRESENTATIONS

45

P1 Towards a computational analysis of DNA damage produced by gold nano- particle enhanced radiotherapy

B. Villagomez-Bernabe and F.J. Currell, Centre for Plasma Physics.

School of Maths and Physics, Queen’s University, Belfast, BT7 1NN, UK.

Due to Gold nanoparticles (GNPs) have a high photoelectric absorption coefficient, they’re able to create an Auger electron cascade when interacts with radiation, which might cause damage on the tumor, improving conventional radiotherapy. Furthermore, both incident radiation and the Auger cascade can break the water molecules creating a cascade of chemical reactions increasing the damage on the tumor.

Using the Geant4-DNA toolkit, we have simulated the irradiation of a water phantom, which contains GNPs. The entire work is divided in three steps: (1) the physical step, where the radiation interacts with GNPs. (2) The physico-chemical step, where water molecules are disassociated creating new chemical species. (3) The chemical stage, where chemical species are tracked in the medium.

The present work exhibit the results at steps 1 and 2, showing the enhancement of dose deposited in water because of GNPs, also predicts the creation of chemical species due to interactions of incident radiation with both GNPs and water molecules. In a future work, those chemical species will be tracked to analyze its contribution to the dose deposited in the medium to simulate the DNA damage in the tumor.

P2 Correlation effects in the competition between scavenging and recombination

Eyad Al-Samra, Nicholas Green Department of Chemistry, University of Oxford Radical scavenging is a commonly used technique in radiation chemistry.8,9 For some species competition between scavenging and recombination may be the only way to gain insight into their track kinetics. The time-dependent rate coefficient for scavenging a single radical is well known.10,11 However, the transient term in the Smoluchowski theory and the spur kinetics take place on similar timescales, and simulations show that the Smoluchowski theory makes systematic errors in the scavenging rate when such competition is present. It is hypothesised that the independent reaction time theory (IRT) includes a substantial part of the multi-radical correlation effect, by permitting the inclusion of correlations in the initial spatial distribution.12 Monte Carlo random flight (RF) and IRT simulations of the problem presented and compared with simulation based on Smoluchowski’s theory. The results of the IRT and RF simulations are in excellent agreement with each other. However, the results of the Smoluchowski theory simulation do not agree with the other results unless a correction is made. An empirical correction for this correlation effect is suggested.

8 K. Enomoto, J. A. LaVerne and S. M. Pimblott, J. Phys. Chem. A, 110 (2006) 4124. 9 J. A. LaVerne, K. Enomoto and M.S. Araos, Radiat. Phys. Chem. 76 (2007) 1272. 10 M. Smoluchowski, Z. Phys. Chem., 92 (1917) 129. 11 C. H. Bamford, C. F. H. Tipper, R. G. Compton and S. A. Rice, Comprehensive Chemical Kinetics, Vol. 25, diffusion-limited reactions (Elsevier, 1985). 12 V. M. Bluett and N. J. B. Green, J. Phys. Chem. A, 110 (2006) 6112.

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P3 Monte Carlo simulation of low energy electron (1-100 eV) tracks in gaseous and condensed phase water. Marisa E. Smith1,2, Neil Burton1, Nicholas J.B. Green3 & Simon M. Pimblott1,2 1 The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K. 2 The University of Manchester, Dalton Cumbrian Facility, Westlakes Science & Technology Park, Moor Row, CA24 3HA, U.K. 3 University of Oxford, Department of Chemistry, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR U.K. The aim of this project is to simulate attenuation of extremely low energy electrons through water by Monte Carlo simulation using experimentally based collision cross sections for low energy electrons (1-100eV) in gaseous water and amorphous ice. The gamma radiolysis of water and dilute aqueous solutions has a G-value yield of 0.45 molecules of molecular hydrogen per 100 eV energy deposited. However, the experimental studies for radiolytic yields of molecular hydrogen from certain water - oxide systems can be two to three orders of magnitude larger than this bulk water value. The mechanism for the excess production is unclear; however, it has been suggested that the increased yield is due to the transport of low energy electrons from the solid oxide into the liquid water phase. Furthermore, there is no current experimental evidence for excess production of oxidant, molecular oxygen or hydrogen peroxide. The data presented will provide insight into low energy electron track structure in water, especially amorphous solid water as a model for liquid water. Specific comparisons will include the range and penetration of the electron tracks as a function of energy, as well as the axial and radial components of the penetration. These results will be explained by examining the average frequencies at which elastic and inelastic events occur in an electron track as a function of initial electron energy. Finally, the distribution of interactions that take place within the 3-dimensional simulation space will be presented as 2-dimensional contour plots. Acknowledgements: This research is supported by the Dalton Cumbrian Facility Project, a joint initiative of the University of Manchester and the Nuclear Decommissioning Authority. MES is a Presidential Scholar at The University of Manchester.

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P4 Size effects and the role of diffusion in nanoparticle therapy Wardlow, N.J.1,*, Baldacchino, G.2, Brun, E.3, Yann Chalopin, Y.4, Gilles, M.3, Kelsey, C.1, McQuaid, H.1, Polin, C.1, Sicard-Roselli, C.3, Soussi, J.4, Currell, F.J.1

1 School of Mathematics and Physics, Queen’s University Belfast 2 Laboratoire de Radiolyse, CEA Saclay 3 Laboratoire de Chimie Physique, Université Paris-Sud Orsay Cedex 4 École Centrale Paris Heavy-element nanoparticles (NPs) have been shown to drastically improve radiation damage [1]. The Hydroxyl radical, HO•, is known to cause around 70% of DNA damage in conventional radiotherapy – we investigate the variation of HO• enhancement with NP size. As expected, the measured data shows significant variation of enhancement with NP size for a fixed nanoparticle concentration. The variation in enhancement is linear with the nanoparticle size, with an apparent minimum size below which there is no enhancement, We present a possible explanation for these unexpected findings, and highlight the process of diffusion as having a large role in explaining the linear nature of the observed relationship. We present the development and outcomes of a model outlining this diffusion effect and compare with our observed physical results, measured using the Diamond Light Source [2]. Full understanding of the mechanisms at work will assist in development of better nanoparticle dose enhancing agents and could have wider implications for nanomedicine in general. References [1] K.T. Butterworth, S.J. McMahon, F.J. Currell, K.M. Prise, Physical basis and biological mechanisms of gold nanoparticle radiosensitization, Nanoscale, 4, 2012. [2] C. Sicard-Roselli et al A New Mechanism for Hydroxyl Radical Production in Irradiated Nanoparticle Solutions, Small, Early View 26th May 2014. P5 Radiation Induced Chemical Changes to Iron Oxides Sarah C. Reiff and Jay A. LaVerne Radiation Laboratory and Department of Physics, University of Notre Dame, Notre Dame, IN 46556 The radiolysis of FeO, Fe3O4 and Fe2O3 powders with different amounts of associated water has been performed using gamma rays and 5 MeV He ions. Temperature programmed desorption and diffuse reflection infrared Fourier transform spectroscopy was used to characterize water species at the surfaces. Physisorbed water is unstable on FeO and Fe3O4 so no H2 is observed in radiolysis, but the yield of H2 from water adsorbed on Fe2O3 is several orders of magnitude greater than that of bulk water. Aqueous slurries of FeO, Fe3O4 and Fe2O3 examined as a function of water fraction gave different yields of H2 depending on the oxide type and the amount of water. Examination of the iron oxide powders following irradiation by x-ray diffraction showed no change in crystal structure. Raman spectroscopy of the oxides revealed the formation of islands of Fe2O3 on the surfaces of FeO and Fe3O4. X-ray photoelectron spectroscopy of the oxides revealed the formation of a new oxygen species by radiolysis.

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P6 The Radiolytic Steady-State and Factors Controlling H2 Production Thomas Donoclift (a,b), Howard E. Sims (a,c) , Robin Orr (d), Simon M. Pimblott (a,b) a The University of Manchester, Dalton Cumbrian Facility, Westlakes Science and Technology Park, Cumbria, UK b The University of Manchester, School of Chemistry, Oxford Road, Manchester, UK c National Nuclear Laboratory, Harwell Business Centre, Didcot, Oxon, UK. d National Nuclear Laboratory, Central Laboratory, Seascale, Cumbria, UK The radiolysis of water and aqueous solutions is known to produce stable molecular species such as H2, O2 and H2O2 as well as a number of reactive radical species such as ∙OH, ∙H, eaq

- , HO2∙ and H+. These molecular products are unfavourable in many processes in the nuclear industry; H2 and O2 pose a combustion hazard while H2O2 and other radical species accelerate corrosion processes. It is therefore important to be able to understand and predict the concentrations of radiolytically produced species over long periods of time and under a variety of physical and chemical conditions. Deterministic models of water radiolysis have been made by solving simultaneous differential equations that represent chemical reactions in a radiolysis process. Combined with experimental studies, computational radiolysis models provide an invaluable means for investigating the radiolysis chemistry of not only water, but that of a variety of aqueous solutions and mixtures. Such studies are necessary for understanding the chemistry of situations in which “legacy waste” is involved, such as the Magnox spent fuel ponds at Sellafield Ltd. These legacy ponds contain high concentrations of numerous corrosion products from spent fuel cladding and various waste containers that have been left for decades. Said corrosion products are mainly magnesium hydroxide, hematite, and magnetite and can alter radiolysis chemistry in a number of different ways.

P7 Experimental and Computational Analysis of Nitric Acid Radiolysis Zoe Tweddle (a,b), Simon M. Pimblott (a,b) a The University of Manchester, Dalton Cumbrian Facility, Westlakes Science and Technology Park, Cumbria, UK b The University of Manchester, School of Chemistry, Oxford Road, Manchester, UK Nitric acid is exposed to radiation at various stages of the nuclear fuel cycle, causing the destruction of the nitric acid molecule and the production of various reactive nitrogen and oxygen containing species, such as NO3

•, •O• and NO2•.

These in turn can react with water radiolysis products creating products such as nitrous acid, hydrogen peroxide and dangerous gases such as H2 and NOx. Their production results in the de-acidification and de-nitrification of the solutions and can disrupt and degrade sealed systems with increased pressure and container damage. As nitric acid is a key component in the PUREX process and present in HAL storage tanks (HASTs), in which the chemical disruption of the solution can lead to the precipitation of radioactive isotopes and the destruction of nitric acid produced pacification layers on the stainless steel containers, compromising their structural integrity. Whilst the consequences of nitric acid radiolysis are known, the specific radiolytic processes important in long term irradiation are less understood and studied. A computational model of nitric acid radiolysis incorporating the indirect and direct processes of nitric acid radiolysis is being produced. This model is accompanied by experimental data both from original work and previous published sources. Using the experimentally collected data the model will be able to be altered to include parameters such as nitric acid concentration and volume, system temperature and pressure and contaminants found in nuclear nitric acid systems, including Ce(IV)/Ce(III), AcNO3 and HMoO4. Further work will result in a model that will incorporate the conditions found when nitric acid is used in industry.

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P8 Source of the hydrogen yield in high temperature water radiolysis Marcin Sterniczuk and David M. Bartels* E-mail: bartels.5@ nd.edu; phone (574) 631-5561; fax: (574) 631-8068 Notre Dame Radiation Laboratory & Department of Chemistry and Biochemistry University of Notre Dame, Notre Dame, IN, 46556 USA Molecular hydrogen is a primary product of water radiolysis, and it has long been understood that it must be produced from intra-spur recombination of H atoms and hydrated electrons. The expectation, based on measured reaction rates, is that this recombination process should become less important at higher temperature, and yet the G(H2) (molecules produced per unit energy of radiation) increases with temperature. Very early in the development of models of the spur recombination chemistry, it was deduced that there must be an additional source of H2 from events in the subpicosecond physico-chemical stage of track evolution. Much more recently Pastina, et al ( J. Phys. Chem. A 1999, 103, 5841-6) demonstrated that the "ultrafast" H2 could be suppressed at room temperature by high concentrations of efficient pre-solvated electron scavengers which are known to prevent formation of (e-)aq. In the present work, we extend the study of G(H2) with presolvated electron scavengers up to 350oC. A simple analysis is introduced which allows us to separate the G(H2) into the "ultrafast" and spur recombination components. The increase of G(H2) with temperature is mostly due to increase of the ultrafast component. We demonstrate that the C37 efficiency variables are very similar for both (e-)aq and H2 suppression. We suggest that dissociative electron attachment to water molecules with a broken hydrogen bond is the most obvious mechanism to explain the temperature behavior of G(H2). This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under award number DE-FC02-04ER15533.

P9 Gold nanoparticles functionalization notably decreases radiosensitization through

hydroxyl radical production under ionizing radiation

Manon Gilles, Emilie Brun, Cécile Sicard-Roselli Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud, 91405 ORSAY Cedex, France. With the objective to reduce radiation deleterious impact to healthy tissues, metallic nanoparticles combined to ionizing radiation have been several times shown to be very efficient. Nevertheless, the absence of a clear knowledge of the species produced when nanoparticles interact with photons prevents the optimization of this phenomenon. Based on a new protocol established to quantify hydroxyl radicals [1], we were able to quantify the major species emitted by the nanoparticle submitted to X –Ray radiation i.e. secondary electrons, hydroxyl radicals (HO•) and superoxide anions (O2

•-

). These results are of high importance as these radicals are known to induce specific deleterious damages to cellular components. As nanoparticles are generally functionalized to target specific cells or get coated as they enter a biological fluid, we studied the impact of several types of coating on the production of these species [2] and demonstrated that their production was highly decreased in the presence of a dense functionalization. This work is a crucial step to design the most efficient nanoparticle for radiotherapy.

[1] Sicard et al. Small 2014 10(16) 3338–3346 [2] Gilles et al. Colloids and Surfaces B, 2014, 123, 770-777

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P10 Assessment of very degraded wooden artefacts consolidation by impregnation with a

radio-curing resin

Ioana Rodica Stanculescu1,2, D.C. Negut1, C. Pintilie1, Maria Mihaela Manea1, M.Virgolici1, I.V. Moise1, L. Dragomir,3 L. Cortella,4 Q.-K. Tran4

1) Horia Hulubei National Institute for Physics and Nuclear Engineering, Centre of Technological Irradiations IRASM, 077125 Magurele, Romania, istanculescu@nipne.ro 2) University of Bucharest, Department of Physical Chemistry, 030018, Bucharest, Romania 3) Association for Heritage Protection, Bucharest, Romania 4) Atelier Régional de Conservation-Nucléart, CEA-Grenoble, France The biological and physical chemical factors affect wooden cultural heritage items, causing discoloration, changes in appearance, loss of strength and elongation and partial or total destruction of the material with underlying chemical changes. The use of radio-curing resin to enhance the material properties is an interesting application of gamma ray irradiation processes for cultural heritage artefacts conservation. It has demonstrated to be very helpful for preserving hugely degraded wooden artefacts when classical consolidation was insufficient, or to preserve the function of an artefact subjected to mechanical constraint, or in the treatment of archaeological waterlogged wood when associated with metal that could presents significant risk of corrosion by conventional processing techniques. Wooden artefact condition assessment and identification of changes in wood structure after consolidation by radiopolymerization using Infrared spectroscopy and thermogravimetric methods in correlation were done. TG/DSC - Netzsch STA 409 PC Luxx Simultaneous Thermal Analyzer and Bruker Vertex FTIR/FT-Raman spectrometer equipped with a TGA-IR unit were used. Vibrational spectra provided information about changes in the molecular structure of different wood type components due to biological or photophysical decay and in situ polymerization by irradiation. Thermal analysis showed changes of chemical composition and thermal stability of wooden cultural heritage objects due to natural ageing and gamma irradiation consolidation. I. Stanculescu, L. Dragomir, M. Mocenco, C. Pintilie, B. Lungu, D. Negut, M. Cutrubinis, M. Virgolici, V. Moise, L. Cortella, Q.-K. Tran (2014), Consolidation of wooden artefacts by resin impregnation and radiopolymerization, Restitutio, Volume 8, Pages 271-275. Acknowledgement. This work was supported by an IFA-CEA grant, contr. no. C3-05/2013.

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P11 Gamma pre-irradiation effects on natural dyeing performances of wool fabrics Ioana Rodica Stanculescu1,2, Maria Mihaela Manea1, M.Cutrubinis1, I.V. Moise1, Laura Chirila2, Alina Popescu2

1) Horia Hulubei National Institute for Physics and Nuclear Engineering, Centre of Technological Irradiations IRASM, 077125 Magurele, Romania, mmanea@nipne.ro 2) University of Bucharest, Department of Physical Chemistry, 030018, Bucharest, Romania. 3) National Research & Development Institute for Textile and Leather, 16 Lucretiu Patrascanu, 030508, Bucharest, Romania The objective of this study was to improve the performance of natural dyeing on fabrics made of 100% wool by gamma pre-irradiation. For this purpose, the fabrics were subjected to irradiation with different doses in the range of 0 - 40 kGy using a Co-60 gamma irradiator and then subjected to natural dyeing by discontinuous exhaustion processes. Due to the lack of colour reproducibility in natural dyeing a natural commercial dye Itodye Nat Pomegranate has been used. The mordanting of pre-irradiated and naturally died fabrics has been performed using iron alum. To establish the effectiveness of gamma pre-irradiation treatment on natural dyeing, measurements for colour and colour fastness to washing, light, wet and dry rubbing, acid and alkaline perspiration were performed. The results obtained were analysed in comparison with those recorded for non-irradiated and dyed fabrics. The investigation of the effect of gamma radiation on textile materials dyed was carried out by assessing the physical-chemical characteristics of the dyed textile materials. Infrared spectroscopy was used to monitor chemical and structural changes in fibers induced by gamma irradiation and dyeing. Surface modifications of wool fibers, as an effect of gamma radiation treatment and natural dyeing processes were emphasized by scanning electron microscopy. I.V. Moise, I. Stanculescu, V. Meltzer, J Therm Anal Calorim (2014) 115:1417–1425 Acknowledgement. This work was supported by grant of UEFISCDI, project TEXLECONS, contr. no. 213/2012 and PN 09 10 02 26. The authors are grateful to Mr. Marian Rascov for Infrared spectroscopy measurements.

P12 Investigating the Radiolytic Hydrogen Production of TODGA (N,N,N’,N’- tetraoctyl

diglycolamide hydrogen

Katherine Bates, Simon M. Pimblott Dalton Cumbrian Facility, University of Manchester, Westlakes Science Park, Moor Row, Cumbria, CA24 3HA A complete understanding of the radiolysis of reprocessing systems is essential for the safe engineering of future processing systems. As part of this the gaseous molecular hydrogen produced from both radiolysis and hydrolysis is essential to understand. It will provide crucial information for the safe engineering of systems, namely to put in place measures to ensure that flammable gaseous build up does not reach dangerous levels under all theoretical working conditions. Using n-dodecane as a substitute for OK (odourless kerosene) the production of hydrogen from the gamma radiolysis of TODGA/n-dodecane mixtures is currently under investigation. Using a Co-60 gamma source and gas chromatography the hydrogen production is measured as a function of both dose (kGy) and dose-rate (Gy/min). Preliminary results and conclusions are presented along with an overview of further work. The research is part of the SACSESS project and is supported by NNL and the University of Manchester. The experimentation is being performed at the state of the art research base of the Dalton Institute, the Dalton Cumbrian Facility (DCF), and in cooperation with NNL’s Central Laboratory on the Sellafield site.

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P13 A new research platform for radiochemistry and other radiation research at Queens

University, Belfast

C. Figueira, R. Cohen, M. O’Leary, C. Polin, N.Wardlow and F.J. Currell Centre for Plasma Physics, School of Maths and Physics, Queen’s University, Belfast, BT7 1NN, UK We have developed a flexible robotic radiation research platform. Samples can be irradiated either horizontally or vertically using a small bespoke X-ray source with interchangeable anodes (variable spectrum). One of the key operational modes involves irradiating hanging drips, suspended from one of 15 robotically selectable nozzles, each driven by a syringe pump. This approach provides a quasi-containerless environment important for studying effects of liquid-solid interfaces. Each sample is stored separately for subsequent analysis. Alternatively wells can be preloaded with sample and irradiated by bringing each one into the beam (vertical irradiation) in turn. Depending on the dose and dose rate required, up to 384 separate samples can be irradiated without user intervention. Furthermore, the whole irradiation system will (after a small upgrade) be able to be enveloped in a blanket gas making studies on the role of dissolved gasses possible. Finally, a range of dosimetric tools are being developed to fully characterize the irradiations delivered. These include the use of 3-dimensional cast resin dosimeters. We envisage using this apparatus both for in-house research and collaboratively with visitors so interested parties are encouraged to visit our poster to discuss possible collaborative studies using this research platform. P14 Synthesis of cellulose derivative based superabsorbent hydrogels by radiation induced

crosslinking

Tamás Feketea,b, Judit Borsab,c, Erzsébet Takácsa,c, László Wojnárovitsa

aInstitute for Energy Security and Environmental Safety, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary bFaculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics cFaculty of Light Industry and Environmental Engineering, Obuda-University Four well known cellulose derivatives (carboxymethylcellulose sodium salt – CMC-Na, methylcellulose – MC, hydroxyethylcellulose – HEC and hydroxypropylcellulose – HPC) were studied as raw materials for biodegradable hydrogels. The systematic synthesis and complex characterization of the hydrogels gave an opportunity for a wide and unique comparison of these derivatives both in theoretical and practical issues of cellulose based hydrogels. Samples with high water uptake were prepared by ionizing radiation induced crosslinking of aqueous solutions of these derivatives. The gel fraction increased with absorbed dose, while water uptake decreased. At high polymer concentrations lower gel fractions were found due to the lower polymer chain mobility and inhomogeneity at low water content. The swelling rate gradually slowed down after 4-5 hours. CMC and HEC gels reached equilibrium after 24 hours, while HPC and MC gels required longer immersion times. Gels exhibited second-order swelling kinetics in water. The mechanism of the water diffusion proved to be anomalous. In pure water, CMC gels showed the highest, while HPC and MC gels the lowest water uptake. This order of derivatives has changed in electrolyte solutions due to the different sensitivities to ionic strength and salt type. Thus assorted cellulose derivative based gels may be applied for diverse purposes depending on the environment.

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P15 Molecular hydrogen yields in radiolysis of heterogeneous water/ceramic oxides systems Konrad Skotnicki,1 Monika Celuch,1 Agnieszka Masłowska,2 Joanna Kisała,2 Dariusz Pogocki,1,2 Krzysztof Bobrowski,1

1Institute of Nuclear Chemistry and Technology, 03-195 Warszawa, Poland; 2Faculty of Biology and Agriculture, University of Rzeszów, 35-959 Rzeszów, Poland One of main reasons to study water radiolysis on metal oxides is the fact that this phenomenon occurs mainly in nuclear power plants and nuclear waste disposals, where metal-water contacts take place. In heterogeneous systems, i.e. water/oxide interfacial surfaces there are substantial differences in an interaction of an ionizing radiation with matter. This is due to various mechanisms of energy transfer processes involved in these two systems. It was shown that a high production of molecular hydrogen (H2) can occur during the normal and emergency mode of work in nuclear reactors. Formation of H2 produced in this way does not lead to its high enough concentrations to pose an explosion hazard. However, in a view of safety process its formation can be involved in another critically important phenomenon, so-called Hydrogen Degradation (HD). In the current studies, g-radiolysis experiments in heterogeneous water/ceramic oxides systems were performed in order to investigate influence of the oxide type, the size of particles, pH, temperature, and the presence of chloride anions (Cl−) on H2 yields. The following oxides were used: zirconium oxide (20 nm, 40 nm, 100 nm, 5µm), nickel (II) oxide, niobium (V) oxide, tin (IV) oxide. Metal oxides before preparing suspensions in water were equilibrated in a climate chamber DY110 (ATT) with a controlled temperature and humidity. Irradiations were performed in a 60Co g-source Gamma Chamber (India) with the dose rate 5.2 kGy/h. The H2 yields were determined using a gas chromatograph GC-2010 Plus coupled with a thermal conductivity detector (TCD). It has been shown that the presence of various types of ceramic oxides influences the yield of H2. The yield of H2 in presence of TiO2 and SnO2 is larger than for water without additives. On the other hand, the presence of NiO does not affect the yield of H2. The substantial decrease in the yield of H2 was observed in the presence of Nb2O5.

Acknowledgements: Financial support under Research task No. 7 “Study of hydrogen generation processes in nuclear reactors under regular operation conditions and in emergency cases, with suggested actions aimed at upgrade of nuclear safety” financed by the National Research and Development Centre in the framework of the strategic research project entitled “Technologies Supporting Development of Safe Nuclear Power Engineering” is greatly acknowledged.

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P16 Pulse radiolysis study of temperature effect on reactivity of Cl2•- in aqueous HCl solution

Lukasz Kazmierczak, Dorota Swiatla-Wojcik*, Joanna Szala-Bilnik, Marian Wolszczak

Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Poland *swiatlad@p.lodz.pl The radical anion Cl2

•- is a transient oxidant formed in aqueous solutions containing, Cl- ions and •OH being a strong and unselective oxidant of crucial importance in many reactions of applied green chemistry technologies and coolant chemistry of water-cooled nuclear power reactors. Temperature dependence of the rate constants of Cl2

•- reactions are necessary to model chemistry induced by traces of Cl- ions in these systems. The reactivity of Cl2

•- with H• radical atom has been investigated in separate 17 ns pulse radiolysis experiments by measuring the decay of Cl2

•- in 0.1 M HCl solution saturated with N2 or N2O. The decay profiles of optical absorption at 340 nm has been resolved using the temperature dependence of the rate constant for disproportionation of Cl2

•- in water determined previously [1]. The rate constant for the reaction of Cl2

•- and H• has been found to be (6.5 ± 0.4)×109 M-1 s-1 at ambient conditions. The obtained Arrhenius dependence shows the activation energy of 16.5 ± 2.2 kJ mol-1 over the temperature range 25 – 75 oC. The temperature dependence of k(Cl2•- + H•) is well described by the Smoluchowski equation assuming the encounter distance and the spin statistical factor of 0.375 nm and 0.25, respectively. Acknowledgment. Research task No. 7 “ Study of hydrogen generation processes in nuclear reactors under regular operation conditions and in emergency cases, with suggested actions aimed at upgrade of nuclear safety” financed by the National Research and Development Centre in the framework of the strategic research project entitled “Technologies Supporting Development of Safe Nuclear Power Engineering” financial support is greatly acknowledged. References 1. J. Szala-Bilnik, P. Pierscieniewska, M. Wolszczak, D. Swiatla-Wojcik, Radiat. Phys. Chem. 97 (2014) 184.

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P17 Vacuum Ultraviolet Spectroscopy of Sub- and Supercritical Fluids Timothy W. Marin1 and Ireneusz Janik2

1Chemistry Department, Benedictine University, 5700 College Rd., Lisle, IL 60532, USA 2Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame IN, 46556, USA We present a unique high-sensitivity vacuum ultraviolet absorption measurement to directly probe electronic states of various fluids from room temperature up to supercritical conditions. Above the critical point, density-dependent data are also obtained. Data are presented for supercritical water, alcohols, ethers, aromatics, and carbon dioxide. We also reveal new information on the temperature dependence of the charge transfer to solvent transition for aqueous hydroxide and iodide, extending information from many previous studies from < 100 °C up to supercritical conditions. Results likely confirm predicted changes in the properties of the anion solvent shell as a function of temperature. Particularly, we suggest that VUV measurements of the water absorption are the most extensive to date, and we will be able to provide extinction coefficients from 1450-2200 Å over the entire temperature and density range examined. The lowest-lying absorption band for water is seen to gradually red shift as a function of increasing temperature, likely confirming purported weakening of the hydrogen bond network. Above the critical point, the gas-phase water monomer spectrum can be replicated in the low-density limit, where hydrogen bonding can be considered negligible. With increasing density, the energy gap gradually blue shifts, presumably with an increase in the extent of hydrogen bonding. P18 Hydrogen production in irradiated sludge mimics M. O’Leary, C. Johnston, G. Tribello, J. Kohanoff and F.J. Currell School of Maths and Physics, Queen’s University, Belfast, BT7 1NN, UK The Pile Fuel Storage Pond (PFSP) and the First Generation Magnox Storage Pond (FGMSP) represent two of the highest priority targets for risk reduction at the Sellafield Site. These legacy ponds have accumulated deep layers of sludge over many years, formed from primarily wind blown debris and decaying organic matter in the case of the PFSP, and mostly from corroding Magnox alloy in the FGMSP. These sludges are of complex and uncertain composition. Additionally they contain fragments of spent fuel where cladding has failed, or in the case of Magnox fuel elements, where cladding has corroded entirely. The production of methane and hydrogen gas complicates the future handling and storage of these sludges. While much of the hydrogen generation from the FGMSP can be attributed to the continuing reaction of the magnesium-based Magnox alloy with water, the radiolysis of water is suspected to be a minor secondary route arising due to the high-gamma flux from fission products. As the sludges are to be moved to new storage areas, during this move there will be a screening which large particulates will be removed from the sludges; this process will effectively remove corrosion as a hydrogen producer, leaving radiolysis as the primary route for hydrogen production. This research will attempt to give quantitative estimates for hydrogen production through the use of multi-scale atomistic modeling and the irradiation of representative sludge samples. Experiments will determine basic radiochemical properties of Magnox and PFSP sludges. In particular the radiolytic production of H2 in these sludges will be studied. These experiments involve using our automated X-Ray radiation platform to irradiate, with a high throughput, a large variety of test materials. Furthermore, our mobile automated end-station can be taken to other radiation sources (subject to beam-time availability) for irradiation ions as well as photons. There are also plans to build an X-Ray source for irradiating sludges. This source will be used to irradiate bigger samples from multiple directions. G-values for the production of a number of end products will be measured using a variety of methods involving the determination of final chemical end products (e.g. spectroscopically or electrochemically). The comparison of atomistic simulations of the sludges to these experimental results can be used to distinguish different chemical pathways for this process.

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P19 New gamma facility at IARC, Poland, for research, pilot-scale studies and small-scale custom irradiation services Piotr Ulański*, Krzysztof Hodyr, Jerzy Gębicki, Andrzej Marcinek Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland Most gamma irradiation facilities can be divided into two groups. Radiation industry runs large, automated gamma sterilization stations, while in the research labs we operate small “Gammacell”-type, self-shielded irradiators. Large industrial facilities are not suitable for research purposes, and in most cases also not practical for pilot-scale tests on new technologies and products. On the other hand, small lab irradiators usually have limited capacity, both in terms of sample compartment volume and dose rates. A solution to bridge this gap is a radiation chamber with a panorama-type source, which is moved out of a fixed shielded container. At the Institute of Applied Radiation Chemistry, Lodz University of Technology, Poland, such a chamber has been built and put into operation in 1960’s. It used a custom design, with 20 60Co sources, each of them moving separately in an independent steel channel. Rising the source was done by pushing it up the channel with compressed air, where it was subsequently hold in the working position by an electromagnet. This presentation describes a new facility of this kind at the Institute of Applied Radiation Chemistry, Lodz University of Technology, Poland. It is based on a panorama-type dry-storage irradiator with 60Co sources (OB-Servo-D, Izotop, Hungary) installed in a 14 m2 (32 m3) radiation chamber. This setup, containing 60 kCi of 60Co, provides the possibility to irradiate samples at dose rates up to 3 kGy/h. It is equipped with 6 rotating tables, 250 kg capacity each, which allow to irradiate larger amounts of materials at an average dose rate of ca. 0.6 kGy/h. Besides, even larger quantities and/ or bulky items can be irradiated using the remaining space. This new facility has been launched in July 2014. It will facilitate technology development projects involving ionizing radiation as well as provide small-scale services to external customers, but first of all it will serve the scientific community. We invite radiation chemists, physicists and biologists to cooperate with us and to use this new facility.

P20 Structure dependence of the rate coefficients of hydroxyl radical+aromatic molecule reaction

László Wojnárovits, Erzsébet Takács Institute for Energy Security and Environmental Safety, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary The rate coefficients of hydroxyl radical addition to the rings of simple aromatic molecules (kOH) were evaluated based on the literature data and date measured by the authors. By analyzing the methods of kOH determination and the data obtained, the most probable values were selected for the kOH's of individual compounds and thereby the most reliable dataset was created for monosubstituted aromatics and p-substituted phenols. For these compounds the rate coefficients fall in a narrow range between 2×109 mol−1 dm3 s−1 and 1×1010 mol−1 dm3 s−1. Although the values show some regular trend with the electron donating/withdrawing nature of the substituent, the log kOH−σp Hammett substituent constant plots do not give straight lines because these high kOH's are controlled by both, the chemical reactivity and the diffusion. However, the logarithms of the rate coefficients of the chemical reactivity controlled reactions (kchem), are calculated by the equation 1/kOH =1/kchem + 1/kdiff, and accepting for the diffusion controlled rate coefficient kdiff =1.1×1010 mol−1 dm3 s−1, show good linear correlation with σp.

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P21 Radiation Damage at Work? Microspec @ Diamond and diffraction @ an XFEL Ian Carmichael1, Robin L. Owen2, Jonathan C. Brooks-Bartlett3, Elspeth F. Garman3 1Notre Dame Radiation Laboratory, University of Notre Dame, Indiana, IN 46556 USA 2Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE 3Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU Email: carmichael.1@nd.edu There is renewed interest in understanding the radiation chemistry that underpins the observed effects of radiation damage during room temperature (RT) macromolecular crystallography experiments. Thus we probed the role of crystallization buffers in the process, and in 2013 reported an unusual optical absorption spectrum collected during X-irradiation of the mother liquor of crystallization buffers at RT using an inline microspectrophotometer and a humidification device mounted on beamline I02 at the Diamond Light Source [1]. Recent attempts to further explore such absorbances at RT, obtained upon irradiation under similar conditions at beamline I24, of a wide variety of commonly used crystallization screens are discussed. Küpper et al. recently reported diffraction from isolated, and strongly aligned, gas-phase 2,5- diiodobenzonitrile molecules with ultrafast (~60 fs) pulses from an X-ray free electron laser [2]. The apparent distance between the principal scattering centres, presumably located on the iodine nuclei, was approximately 8 Å. However, quantum chemical (QC) calculations suggest an I–I distance of only 7 Å in the neutral molecular species. At the wavelength employed, ~6 Å, photoabsorption events will greatly outweigh elastic scattering from these centers, suggesting perhaps that the recorded pattern may not result from undamaged molecules. We have carried out QC calculations to elucidate the properties of other candidate molecular states that may account for this discrepancy, and results from these computations are presented. References [1] Allan E.G.; Kander M.C.; Carmichael I.; Garman E.F. J. Synchrotron Radiat. 20, 23-36 (2013). [2] Küpper J.; Stern S.; Holmegaard L. et al. Phys. Rev. Lett. 112, 083002 (2014).

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P22 Development and perspective of the atto-second pulse radiolysis Masao GOHDO, Koichi KAN, Takafumi KONDOH, Jinfeng YANG, Yoichi YOSHIDA The Institute of Scientific and Industrial Research, Osaka University, N404, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan A lot of efforts have been paid to improve the time resolution of a pulse radiolysis. An ultra-short accelerated electron beam required to achieve the development of ultra-fast spectroscopic measurement system. However, such short electron beam had not obtained before the appearance of a photo-cathode RF electron gun linac. Therefore radiochemical phenomena just after the ionization to sub-femto seconds has been discussed based on simulations and have been remained to be examined. At ISIR, a photo-cathode RF gun linac has been developed to improve the time resolution of a pulse radiolysis technique. Recently, an ultra-short and high quality accelerated electron beam of femto-second time scale was successfully generated and the application of the ultra-short electron beam on a pulse radiolysis technique with new measurement system is in progress. We started the challenge to realize the atto-second pulse radiolysis. Resent advances of ultra-short electron pulse generation and pulse radiolysis measurement system in ISIR will be introduced. Pulse radiolysis study of polystyrene dimer phenyl cation radical in THF Masao GOHDO, Takafumi KONDOH, Koichi KAN, Jinfeng YANG, Hiromi SHIBATA, Seiichi TAGAWA, Yoichi YOSHIDA Fraction ratio of polystyrene (PS) dimer phenyl cation radical formation and recombination between monomer cation radical of PS and electron were studied by means of pulse radiolysis technique in fluid solution to understand the ”protective effect” of PS under ionizing radiation. It is well known that polymers degrade under an ionizing irradiation, however, some polymers like PS suffer under those conditions. The protective effect of PS has been explained by its efficient formation of dimer cation radical and exited state or excimer, and those transients are inert. In this study, intra-molecular process of dimer cation radical formation and excimer formation were examined in tetrahydrofuran (THF) solution. PS concentration dependence on yield of the dimer cation radical of PS and the solvated electron were observed by nano-second pulse radiolysis. In addition, direct observation of formation of dimer cation radical and excimer were made by femto-second pulse radiolysis. The yield of dimer cation radical of PS increased linearly when the concentration of PS increased. Besides the yield the solvated electron decreased when the PS concentration was increased but the decay rates of the solvated electron did not affected by the PS concentration. It is believed that there is no hole transfer from THF cation radical to solute molecule, therefore, the cation species of PS supposed to be formed by the direct ionization of PS. The reaction ratio of dimer radical formation and recombination was estimated to be 7 : 3 and formation rate constants of dimer cation radical and excimer were found to be >7x1010 s-1 and >4x1010 s-1, respectively.

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P23 Assessing the Influence of Copper binding to DNA on Radiation-Induced Strand and Base Damage in a Hydrated DNA Model Steven G. Swarts Department of Radiation Oncology, University of Florida, Gainesville, Florid, USA PURPOSE: A hydrated DNA model is used to assess how copper bound to DNA influences the damaging effects of not only the direct radiolysis of DNA but also the differing damaging effects on DNA from the radiolysis of bound and bulk water. METHODS: Salmon sperm DNA is doped with copper at level of 1:20 Cu+2 per nucleotide. A second DNA model that is doped with Zn+2 at 1:20 per nucleotide as a control for the steric and DNA conformational effects of bound copper in the model. A third model is the undoped salmon sperm (as the sodium salt). DNAs were hydrated to levels of 2.5,10,13,22 and 32 water molecules/nucleotide (Γ) and irradiated to doses of 0,10,35,65 and 90 kGy. Following post-irradiation processing of the DNA, base release from the DNA is measured by HPLC, and 13 chemically-altered DNA bases are measured by GC/MS. RESULTS: Total yields of DNA damage (base release and base damage) in DNA-Cu, DNA-Zn and DNA-Na models hydrated to Γ=10-22 were similar but increased in DNA-Cu and DNA-Na when hydrated to Γ=32. The yield of reduced base damage products was decreased to near zero in DNA-Cu at all hydration levels compared to the other two DNA models. Yields of some oxidative products increased in DNA-Cu, dominated by the production of 8-oxoguanine at all hydration levels. In DNA models hydrated to Γ >22, Fenton-mediated DNA damage becomes the dominant. CONCLUSION: Copper bound to DNA has the effect of increasing oxidative damage in irradiated DNA both through lowering the yields of electron-gain centers formed though the radiolysis of DNA and surrounding water, and through Fenton-mediated DNA damage.

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P24 Radiation grafting of thermosensitive polymer with biologically active agent on polypropylene dishes as new substrates for cell sheet engineering.

Agnieszka Adamusa, Justyna Komasaa, Sławomir Kadłubowskia, Róża Trzcińskab, Piotr

Ulańskia, Barbara Trzebickab, Andrzej Dworakb, Janusz M. Rosiaka

aInstitute of Applied Radiation Chemistry, Technical University of Lodz, Wroblewskiego 15, 93-590 Łódź, Poland bCentre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Skłodowskiej 34, 41-819 Zabrze, Poland

Burn wounds are one of the most frequently occurring injuries. This kind of wound is a serious problem not only because of its high happening frequency, but also due to the complications arising during its healing. Many conventional treatments of burn wounds are costly, slow and not effective. Nowadays we can observe a fast progress of knowledge about processes occurring in wound and ways of its healing. Skin grafts are considered to be one of the best solutions; however, cell culture procedures used to obtain large-surface grafts still to be optimized. A persisting problem is how to detach the grown skin sheet from the substrate without causing excessive damage to the product. One of the possible solutions is to use substrates with thermo-responsive surfaces. The latter is currently recognized as valuable new materials with novel properties relevant for biomedical research fields such as artificial organs, biofunctional materials, drug delivery systems, separations of biomolecules, and regenerative medicine.

Thermoresponsive polymers are commonly used as surface modifiers. One of the polymers being of particular interest for mentioned application, namely poli(ethylene glycol) ethyl ether methacrylate POEGMA, belongs to the family of polymethacrylates. POEGMA has a lower critical solution temperature (LCST) of 21ºC in water. Below LCST the polymer is fully hydrated and soluble in water, but above the LCST macromelecule collapses and becomes insoluble.

The aim of this work was to graft thermo-responsive polymethacrylate (POEGMA) with the addition of custom-synthesized oligopeptide (IKVAV) onto polypropylene (PP) cell culture dishes. POEGMA modified polypropylene were used for development of new, innovative thermocontrolled scaffolds for culturing skin and epithelial cell sheets. The aim of addition of IKVAV was to make the surface more adhesive for cells layer. Influence of peptide concentration on grafting percentage was studied.

Samples were prepared by copolymerization of poly(ethylene glycol ethyl ether methacrylate) with pentapeptide (IKVAV methacrylamide, IKVAV-met). Grafting was done by pre-irradiation approach. In this process polypropylene dishes were irradiated with 150 kGy by 6 MeV electrons from a linear accelerator in the presence of oxygen. This leads to formation of radicals, peroxides and hydroperoxides on irradiation surface. Further irradiated surface was placed in the combinations of isopropanol monomers with IKVAV-met, mixture was purged with argon in order to remove oxygen and heated to 70°C for the given time. In this temperature peroxides bonds fall apart, creates labile oxygen radicals which binds the monomer chains together.

Obtained results indicate that addition of IKVAV methacrylate to the POEGMA mixture effects in its incorporation into the grafted polymer layer. To indicate the quantitative percentage of grafted IKVAV pentapeptide methacrylamide with attached carboxyfluoresceine (CF-IKVAV-met) was used as marker. After polymerization, IKVAV with marker is detached from the dish surface by trypsinization. The solution of detached pentapeptide is excited with wave with length of 485 nm, and the intensity of emitted light wave with length of 528 nm is measured. The intensity correlates with the concentration of the IKVAV grafted during polymerization process. It was proved that the amount of the grafted pentapeptide can be controlled by concentration of IKVAV in reaction mixture.

This work was supported by the National Centre for Research and Development, project POLYCELL PBS1/B9/10/2012

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PARTICIPANTS

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Adamus, Agnieszka

agnieszka.adamus @p.lodz.pl

Lodz University of Technology, Institute of Applied Radiation Chemistry, Wroblewskiego 15, 93-590 Lodz, Poland

Al-Samra, Eyad

eyad.alsamra @chem.ox.ac.uk

Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK

Al-Sheikhly, Mohamad

mohamad@umd.edu Department of Materials Science and Engineering, University of Maryland, 2135 Chemical & Nuclear Engineering Bldg #090, University of Maryland, College Park, MD 20742-2115, USA

Baidak, Aliaksandr

aliaksandr.baidak @manchester.ac.uk

The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K.

Bartels, David David.M.Bartels.5@nd.edu Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 USA

Bates, Katherine

katherine.bates@postgrad. manchester.ac.uk

The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K.

Berlin, Yuri berlin@northwestern.edu Northwestern University, Department of Chemistry, Evanston, IL 60208-3113, USA

Bland, Ian Ian.Bland@comet.ch COMET AG, Herrengasse 10, 3175 Flamatt, Switzerland M.

Bobrowski, Krzysztof

kris@ichtj.pl Institute of Nuclear Chemistry and Technology, 03-195 Warszawa, Poland

Brede, Ortwin brede@uni-leipzig.de University of Leipzig

Carmichael, Ian

ianc@nd.edu Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 USA

Clochard, Marie-Claude

marie-claude.clochard @polytechnique.edu

Laboratoire des Solides Irradiés, Ecole Polytechnique, F-91128 PALAISEAU, France

Cui, Zhengpeng

zhenpeng.cui@u-psud.fr Laboratoire de Chimie Physique, LCP, UMR 8000, CNRS, Université Paris-Sud 11, Bât. 349, Campus d'Orsay, 15 avenue Jean Perrin, 91405, France

Currell, Fred f.j.currell@qub.ac.uk Centre for Plasma Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, UK

Dahlgren, Björn

bda@kth.se School of Chemical Science and Engineering, Applied Physical Chemistry, KTH, Royal Institute of Technology Sweden

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Davies, Michael

davies@sund.ku.dk Panum Institute, University of Copenhagen, Blegdamsvej 3, Copenhagen 2200, Denmark

del Mastro, Nelida

nelida@usp.br Institute of Nuclear and Energy Research, IPEN-CNEN/SP Brazil

Domazou, Anastasia

domazou@inorg.chem.ethz.ch

Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, Zurich

Donoclift, Thomas

thomas.donoclift@postgrad.manchester.ac.uk

University of Manchester Dalton Nuclear Institute, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA

Figueira. Catarina

cfigueira01@qub.ac.uk Centre for Plasma Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, UK

Garman, Elspeth

elspeth.garman @bioch.ox.ac.uk

Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU

Ghalei, Mohammed

Mohammad.Ghalei@subatech.in2p3.fr

Subatech, Groupe Radiochimie, E -102, 4 rue Alfred Kastler, 44307, Nantes Cedex , France

Gohdo, Masao Mgohdo @sanken.osaka-u.ac.jp

The Institute of Scientific and Industrial Research, Osaka University, N404, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

Green, Nicholas

nicholas.green @chem.ox.ac.uk

Department of Chemistry, University of Oxford, South Parks Road, OX1 3QR, UK

Horne, Greg gregory.horne@postgrad. manchester.ac.uk

The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K.

Houée Levin, Chantal

chantal.houee@u-psud.fr Laboratoire de Chimie Physique, UMR 8000 CNRS-Univ. Paris Sud, 91405 Orsay France

Illés, Erzsébet illes.erzsebet @energia.mta.hu

Radiation Chemistry Department, Centre for Energy Research, Hungarian Academy of Sciences, Konkoly Thege M. út 29-33, Budapest, H-1121

Janik, Ireneusz ijanik@nd.edu Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 USA

Jonsson, Mats matsj@kth.se School of Chemical Science and Engineering, Applied Physical Chemistry, KTH, Royal Institute of Technology, Sweden

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Kaddissy, Josiane

Josiane.kaddissy@cea.fr CEA/DSM/IRAMIS/NIMBE/LIONS - CEA Saclay - 91191 Gif Sur Yvette Cedex, France

Kadłubowski, Slawomir

slawekka@mitr.p.lodz.pl Lodz University of Technology, Institute of Applied Radiation Chemistry, Wroblewskiego 15, 93-590 Lodz, Poland

Kahnt, Axel axel.kahnt@fau.de Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, 91058 Erlangen, Germany.

Kazmierczak, Lukasz

lukaszkazmierczak7@o2.pl Lodz University of Technology, Institute of Applied Radiation Chemistry, Wroblewskiego 15, 93-590 Lodz, Poland

LaVerne, Jay Jay.A.LaVerne.1@nd.edu Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 USA

Le Caer, Sophie

sophie.le-caer@cea.fr Institut Rayonnement Matière de Saclay, NIMBE, UMR 3685 CNRS/CEA, LIONS, Bâtiment 546 91191 Gif-sur-Yvette Cedex, France

Ma, Jun jun.ma@u-psud.fr Laboratoire de Chimie Physique, CNRS / Paris-Sud University, Buldg. 349, 91405 Orsay, France

Maimon, Eric emymon@bgu.ac.il Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel

Manea, Mihaela

mmanea@nipne.ro Horia Hulubei National Institute for Physics and Nuclear Engineering, Centre of Technological Irradiations IRASM, 077125 Magurele, Romania

Marin, Tim TMarin@ben.edu Chemistry Department, Benedictine University, 5700 College Rd., Lisle, IL 60532, USA

Mizrachi, Amir

amirmizrachi@gmail.com Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel

Mostafavi, Mehran

mehran.mostafavi @u-psud.fr

Laboratoire de Chimie Physique, CNRS / Paris-Sud University, Buldg. 349, 91405 Orsay, France

O'Leary, Mel moleary05@qub.ac.uk Centre for Plasma Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, UK

Pimblott, Simon

Simon.Pimblott @manchester.ac.uk

The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K.

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Polin, Chris cpolin01@qub.ac.uk Centre for Plasma Physics,

School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, UK

Poster, Dianne poster@nist.gov NIST, Gaithersburg MD USA

Ptasinska, Sylwia

Sylwia.Ptasinska.1@nd.edu Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 USA

Roth, Olivia olivia.roth@studsvik.se Studsvik Nuclear AB, SE-611 82 Nyköping, SWEDEN

Schmitz, Pavlina

pavlina.schmitz @chem.ox.ac.uk

University of Oxford Chemistry Research Laboratory, Mansfield Road,Oxford OX1 3TA, UK

Schofield, Jennifer

jennifer.schofield@postgrad.manchester.ac.uk

The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K.

Schöneich, Christian

schoneic@ku.edu Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA

Sicard, Cecile cecile.sicard@u-psud.fr Laboratoire de Chimie Physique, CNRS UMR 8000, Université Paris-Sud, 91405 ORSAY Cedex, France

Sims, Howard howard.e.sims@nnl.co.uk National Nuclear Laboratory, Harwell Science Park, Didcot, Oxon OX11 0QT, UK

Skotnicki, Konrad

k.skotnicki@ichtj.waw.pl Institute of Nuclear Chemistry and Technology, Warsaw, Poland

Smith, Marisa marisa.smith@postgrad. manchester.ac.uk

The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K.

Strzelczak, Grazyna

grazyna@orange.ichtj.waw.pl Institute of Nuclear Chemistry and Technology, Warsaw, Poland

Swarts, Steven sgswarts@ufl.edu Department of Radiation Oncology, University of Florida, Gainesville, Florid, USA

Takács, Erzsébet

erzsebet.takacs @energia.mta.hu

Institute for Energy Security and Environmental Safety, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary

Toohey, Mags magstoohey@gmail.com NUI Galway, Ireland

Tweddle, Zoë zoe.tweddle@postgrad. manchester.ac.uk

The University of Manchester, School of Chemistry, Oxford Road, Manchester, M13 9PL, U.K.

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Ulanski, Piotr ulanskip@mitr.p.lodz.pl Lodz University of Technology, Institute of Applied Radiation Chemistry, Wroblewskiego 15, 93-590 Lodz, Poland

Vandenborre, Johan

Johan.Vandenborre @subatech.in2p3.fr

SUBATECH laboratory - 4, rue Alfred Kastler - La Chantrerie BP 20722, 44307 Nantes cedex 3 – France

Villagomez-Benabe, Balder

b.villagomez-bernabe @qub.ac.uk

Centre for Plasma Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, UK

Walsh, Stephanie

stephanie.walsh@cnl.ca Environmental Technologies Branch, Canadian Nuclear Laboratories, Chalk River, Ontario, K0J 1J0

Wardlow, Nathan

nwardlow01@qub.ac.uk Centre for Plasma Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, UK

Wishart, Jim wishart@bnl.gov Chemistry Department, Brookhaven National Laboratory, Upton, NY, 11973 USA

Wojnárovits, László

wojn@iki.kfki.hu Institute for Energy Security and Environmental Safety, Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary

Wojcik, Mariusz

mariusz.wojcik@p.lodz.pl Institute of Applied Radiation Chemistry, Lodz University of Technology,Wroblewskiego 15, 93-590 Lodz, Poland

Yamashita, Shinichi

shin1@utns.jp Nuclear Professional School, School of Engineering, The University of Tokyo, Shirakata-shirane 2-22, Tokai-mura, Naka-gun, Ibaraki, 319-1188 Japan

Zilbermann, Israel

israelz2003@gmail.com Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel

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