1 hair, fibers and paint che 113 forensic science copyright 2004-2006, james t. spencer

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Hair, Fibers and Paint

CHE 113 Forensic Science

Copyright 2004-2006, James T. Spencer

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Hair Characteristics

Fiber Characteristics

Regenerated Fibers

Paint Chips- color & layer

Automobile finishes

Hair, Fibers and Paint

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Hair is Class Evidence

• Appendage of the skin the grows from a follicle.• Resistant to chemical decomposition and long term

structural stability.• Can often determine body area where the hair originated

and sex of owner.• Can often determine racial origin

Negroidkinky with dense uneven pigmentflat to oval in shape

Caucasoidstraight or wavy, fairly evenly distributed pigment, oval to round shape

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Hair can NOT be individualized through its trace elemental composition. To combat this PCR is used (DNA).

Must have a collection of reference standards to increase degree of probability.

Significant error rates associated with microscopic comparisons, DNA must be confirmed.

When comparing hair - color, length, and diameter important.

Hair is best identified by examining the medulla & cuticle.

Bad

Good

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Hair Morphology

Main Hair Parts:CuticleCortexMedulla

Medulla

Sebaceous (oil) gland

Follicle

Hair Shaft

Erector Muscle

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Hair Morphology

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Hair Morphology

Scales always point to the tip.Scale pattern identifies species.

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Morphology of Hair

Cuticle - scales on exterior of hair shaft (keratinized).

Cortex - main body of shaft, contains pigment granules, shape.

Medulla - either absent or ca. 1/3 the diameter of the shaft (continuous, interrupted, segmented or absent).

Other animals have different properties - Cuticle and Medulla are best used to distinguish if the sample is human or animal.

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Hair Structures

Medulla vary from person to person AND even among hairs from one person.

Three main Medulla types: continuous, interrupted and fragmented.

Growth Phases:– Anagen - initial phase where hair actively grows.– Catagen - transition between active and loss stage

- slowed growth.– Telogen - final phase resulting in hair loss.

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Hair Growth Anagen - up to 6 years (or as short as 3 mo. for

eyelashes or arms). Length of anagen determine max. hair length. Have about 100,000 head hairs.

Catagen - usually up to several weeks. Telogen - up to 6 months. Animals that shed sychronize the telogen phases. Hair grows fairly uniformly at 0.5 mm/day (ca. 6

in./year).

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Records are Interesting?

Anagen period about 10 to 12 years!

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Hair growth

Differences in hair length depend on the length of anagen, which is genetically determined. These two people started off with hair of the same length and went without a haircut for 18 months: the man's hair grows only to his collar before it falls out naturally, but the woman's anagen period is clearly much longer [reproduced from Diseases of the Hair and Scalp, A. Rook and R. Dawber (eds), 2nd edn, Oxford: Blackwell Scientific Publications, 1981]

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Metabolic Effects

(Left) This boy has a zinc deficiency, and his hair is very thin and sparse; (right) after treatment his hair is growing more strongly.

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Hair Coloring 75% of adult females say they

color their hair (7% in 1950). Most popular current color is red. Permanent coloring requires

chemicals to reach into the cortex (through the cuticle). There they react with the cuticle, changing the color and becoming too large to be washed from the hair.

Nasty chemicals involved (ammonia, hydrogen peroxide, etc).

Damaged by “Perming”

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Hair Colors - green?

Natural Green comes from copper in hair. Can come from Cl in pools or Cu water pipes.

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Hair “Perms”

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Hair Split Ends

Severly Damaged Hair - The continuing destruction of the cortex of a hair: the long parallel bundles of keratin have been exposed and can be seen clearly.

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Hair

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Hair - Racial Identification

Mongoloid or Asian hair Negroid or African hair Caucasian or Europeanhair

Grooved (African)

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Knotting, associated with African hair

A healthy hair, its cuticle intact, taken from a newborn baby

Damaged cuticle, due to backcombing heavily sprayed hair

A hair shattered after severe permdamage

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Hair - Species Identification

Muskrat Deer

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Hair - Species Identification

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Hair - Sex Identification

Stained sex chromatin in the nuclei of human cells showing the female-indicative Barr body (bright spot, left) and the male-indicative Y body (bright spot, right)

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Hair

Naturally shed hairs, such as ahead hair dislodged throughcombing, display undamaged,club-shaped roots.

A hair forcibly removed fromthe scalp will exhibit stretchingand damage to the root area.

A razor-cut hair

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Hair

A split hair A hair with a cut tip A postmortem rootband

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Hair

Cross-sections of three hairs, all ofdifferent racial types: (left) Asian, (centre)Caucasoid, (right) African.5

Hair that has not beenwashed for some time.5

Heat damaged hair.5

A micrograph of a hair shaft. Note the layered cuticle on the shaft and the bulb at the bottom

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Forensic Hair Analysis In 1936 the wife of an NBC executive

was killed in their Manhattan brownstone. She had been strangled with her pajama top and left in the bathroom. Indications were that she had known her killer, and when there appeared to be few clues except some twine used to bind her, a chemist was brought in to examine the crime scene.

In the bedroom he found only one strand, half an inch long, of stiff white hair, which he soon identified through a microscope as horsehair. Since two furniture movers had delivered a horsehair couch that morning and it was those men who reported the body, the detective in charge speculated that one of them had paid an earlier call. He identified the likely culprit and then found a connection via the piece of twine, because it had sufficiently distinctive markings to be traced to a manufacturer and distributor. It turned out that the same twine had been sold to the furniture store. Using this evidence to put pressure on the suspect, the detective got the confession he needed for conviction.

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Wayne WilliamsAtlanta child murders case

video of investigation30

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Forensic Fiber AnalysisFrom 1979 to 1981, more than 25 black males had

been strangled, bludgeoned or asphyxiated but all potential leads turned into dead ends.

The only real clue was the presence on several of the bodies of fiber threads. A few also had strands of dog hair.Fibers isolated were two distinct types: a violet-colored acetate fiber and a coarse yellow-green nylon fiber with the type of tri-lobed (three branch) qualities associated with carpets.

Stakeout of river dumping ground paid off when the stakeout patrol heard a loud splash. They stopped a white Chevrolet station wagon driven by Wayne Williams.The police searched Wayne Williams' home and ca, and found floors of Williams' home were covered with yellow-green carpeting, and he also had a dog. Comparisons from the samples removed from the victims showed good consistency with Williams' carpet.

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Characteristics of Fibers

Characteristics– Color, diameter,

birefringence, shape, presence or absence of delustering particles (usually titanium dioxide)

Rayon – is classified as regenerated

fiber (derived from natural material-cellulose)

– First man-made fiber 1911

“poly” meansmany

“mer” meansunit

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PolymersPolymers Natural Polymers

– Biopolymers; Proteins, Polysaccharides, nucleic acids, and others (Spider’s web, wool, etc...)

– Others: Asbestos, Graphite, etc... Synthetic Polymers

– Organic Polymers Synthesized from organic monomers

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BiopolymersBiopolymers

Polymer - large, high molecular weight molecule

formed by joining together a large number of

molecules of low molecular weight.

Proteins - formed from amino acids

Carbohydrates - polyhydroxy aldehydes and

ketones

Nucleic Acids - complex high molecular weight

biopolymres (i.s., DNA)

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Polysaccharides - from labPolysaccharides - from lab

OO

O O

O O

O

O

O

O

OO

O

Starch - Starch - -glucoside linkages-glucoside linkages

Cellulose - Cellulose - -glucoside linkages-glucoside linkages

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Nucleic AcidsNucleic AcidsNucleic Acid Polymer (i.e.,

DNA)PhosphatePhosphate

SugarSugar

BaseBase

PhosphatePhosphate

SugarSugar

PhosphatePhosphate

SugarSugar

PhosphatePhosphate

BaseBase

BaseBasePolymerPolymer

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Spider’s WebSpider’s Web

Spider silk is an extremely strong material and is on a weight basis stronger than steel. It is believed that a pencil thick strand of silk could stop a Boeing 747 in flight. Silk is a 50% polymerized protein with a molecular weight of 200,000 - 300,000 produced by the silk glands in the form of a liquid with a molecular weight of 30,000. The silk polymerizes before it is released from the spinnerets. The primary constituents of spider’s silk are the two simplest amino acids, glycine and alanine.

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Spider’s SilkSpider’s Silk The material is elastic and only breaks at between 2 - 4 times its length. In the pictures, a strand of a social spider (stegodyphus sarasinorum) is shown at normal size, stretched 5 and 20 times its original length.

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Spider’s WebSpider’s WebThe elasticity of spider silk is similar to nylon. Amazingly, the dragline

thread of the garden spider (Araneus) would have to be 80km long before it would snap under its own weight! With respect to elasticity, the spider’s dragline can be stretched by 31% without breaking, whereas nylon will only stretch by 16%.

DuPont's advertisement in the Scientific American of July 1996 describes their work on the biopolymer structures of the spider webs. By using recombinant DNA technology, they have managed to produce analogs of silk in yeast and bacteria and are planning to use this synthesized material for construction and other purposes.

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Spiders SilkSpiders Silk

Composed of disordered portions (like cooked spaghetti) which give flexibility and ordered units (like rods) to give strength.

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Synthetic PolymersSynthetic Polymers

Plastic - “Capable of being molded”. Polymer - large, high molecular weight

molecule formed by joining together a large number of molecules of low molecular weight.

First Synthetic Plastic - 1870 - answer to contest to make artificial (non-ivory) billiard balls.

Plastics - Now they fit needs that NO other materials can fit.....from artificial skin to high strength composites.

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Synthetic Polymers: The StartSynthetic Polymers: The Start Wallace Carothers invented

nylon and neoprene in a single creative burst in the early 1930's. The inventor led us into the synthetic age, bringing synthetic rubber and fiber to DuPont and the world. But Carothers was a troubled man which led to his inevitable fate -- suicide at the age of 41 - by a powerful combination of depression and alcoholism. A biography of Carothers (Enough for One Lifetime) tells his story against the backdrop of the Depression.

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Synthetic PolymersSynthetic Polymers Discovery Channel Special Program on

Polymers

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PolymersPolymers

Since 1935 there has been a 500X increase in plastic production

1985198519351935

Billion

s o

f lb

sB

illion

s o

f lb

s

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Plastics: PropertiesPlastics: Properties

Plastics have an ENORMOUS range of properties - from soft and opaque to very hard and transparent.

The features which account for these range of properties are;– length of chain– 3D arrangement of chains– branching of chain– composition of monomer units– bonding BETWEEN chains– Orientation of monomer units WITHIN chain

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PolymersPolymers Five Monomers make up most of the synthetic

polymers

HC C

H

H

H

HC C

H

H

Cl

HC C

H

H

HC C

H

H

CH3

O

OH

O

HO

+ HOCH2CH2OH

EthyleneEthylene Vinyl Chloride Vinyl Chloride Styrene Styrene

Ethylene Glycol and Terephthalic AcidEthylene Glycol and Terephthalic Acid

PropylenePropylene

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PolyethylenePolyethylene

The Most Common Plastic/Polymer (10 million tons in US annually)

C CH

H

H

HC C

H

H

H

Hn

EthyleneEthylene

CatalystCatalyst

n = number of repeat n = number of repeat unitsunitstypical values range typical values range from 10,000 to 100,000 from 10,000 to 100,000 unitsunits

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PolyethylenePolyethylene High Density

Polyethylene (HDPE) - straight chain polymer - chains “pack” together tightly like a crystal - high density, high strength, high mp

Low Density Polyethylene (LDPE) - branched chain polymer - side groups impede “packing” of the chains - low density, low strength, low mp

HDPEHDPE LDPELDPE

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Condensation PolymersCondensation Polymers

C

O

OHC

O

HO C C

HH

H H

OHHO

C

O

OC

O

HO C C

HH

H H

OH + H2O

+

Addn’l Addn’l ReactivReactive Sitee Site

Addn’l Addn’l ReactivReactive Sitee Site

Polyethylene terephthalatePolyethylene terephthalate

Terephthalic AcidTerephthalic Acid Ethylene Ethylene glycolglycol

EsterEster

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Condensation PolymersCondensation Polymers

Polyethylene terephthalate (PET)Polyethylene terephthalate (PET)

Polyethylene naphthalate (PEN)Polyethylene naphthalate (PEN)

H O C

O

C

O

O CH2

CH2

OH

C

O

O CH2

CH2

OH

C

O

OH

n

n

Know These Two!

PEN is Stronger because the two rings resist bendingPEN is Stronger because the two rings resist bending

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Nylon 6-10Nylon 6-10

Organic Polymer H2N(CH2)6NH2+O

CCl C

O

Cl

NH(CH2)6 N

HCO(CH2)8 C

O

n

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Other PolymersOther Polymers

Carbon Allotropes– Diamond– Graphite– Fullerene

C

C

CC

C

C

C

CC

C

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Carbon PolymersCarbon Polymers

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Feedstock for PlasticsFeedstock for PlasticsMonomeric units for plastic synthesis come from oil.

Gasoline 47%Gasoline 47%

Perc

en

tP

erc

en

t

50%50%

0%0%

Diesel/Home Heating 20%Diesel/Home Heating 20%

OtheOther r

10%10%

Jets Jets 10%10%

BoileBoilers 7%rs 7%

RoadRoads 3%s 3%

PlasticPlastics 3%s 3%

Oil ConsumptionOil Consumption

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Plastics in GarbagePlastics in Garbage

Paper 34%Paper 34%

Perc

en

tP

erc

en

t

50%50%

0%0%

Plastics 20%Plastics 20%Other Other 18%18% MetMet

al al 12%12%

Yard Yard 10%10%

Food Food 3%3%

GlasGlass 2%s 2%

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Fibers

Cotton Wool Linen Nylon Silk Rayon

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Fibers

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Cloth from Fibers

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Shroud of Turin - Fiber Analysis

Cathedral of St. John the Baptist, TurinHome of the Shroud of Turin

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A Forensic Nightmare?

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http://www.shroudstory.com/http://biblia.com/jesusart/turin.htm

The weave of the Shroud of Turin is rich and gold colored under high magnification of a microscope.

http://www.world-mysteries.com/sar_2.htm

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Blood or Paint?

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Pollen Analysis

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Sudarium of Oviedo

One of the relics held by the cathedral in the town of Oviedo, in the north of Spain, is a piece of cloth measuring approximately 84 x 53 cm. There is no image on this cloth. Only stains are visible to the naked eye, although more is visible under the microscope. The remarkable thing about this cloth is that both tradition and scientific studies claim that the cloth was used to cover and clean the face of Jesus after the crucifixion.

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Leonardo

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Camera Obscura

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Camera Obscura

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Camera Obscura

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Wayne Williams

Was identified as the key suspect in the Atlanta Child Murders that occurred between 1979 and 1981. In January 1982, he was found guilty of the murder of two adult men. After his conviction, the Atlanta police declared an additional 22 of the 29 child murders solved.

Hairs and fibers on one of the victims' bodies were found consistent with those from Williams' home, car, and dog.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.



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Paint Colloidal Suspension 3 parts (water-based used emulsions):

– a pigment - particles of a colored compound – a medium - suspends the pigment particles and fixes them to the surface – a volatile diluent liquid - allows control over the consistency of the paint

Paint colors - selective absorbance of portions of the visible spectrum by chemical compound - act as filter, subtracting out portions of the visible spectrum leaving only parts of the spectrum. – pigments - compound that is suspended

in a medium that is bound to a surface.– dye -binds to the surface itself. [paints have

both pigments and media while cloth might be dyed with a compound that binds itself to the surface of the fibers]

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Paint

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Paint Two Filters In Sequence?

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Paint Pigments and Dyes

– traditional pigments are derived from finely ground minerals or inorganic compounds. Most dyes came from organic sources such as berries and insect bodies. Many colored synthetic organic and inorganic compounds are now available.

– Upon Drying - solvent and/or binder transforms into a crosslinked solid by oxydation in air (Oil paints). Other binders crosslink by radical polymerisation mechanisms (e.g. UV curing) or isocyanate reacting with hydroxyl groups to form urethane. Paint films that are crosslinked cannot be dissolved



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Paint Digital video micrograph of a binary array of polystyrene microspheres in the rock salt structure

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Paint chips- individualized to a single source by examining color and layer structure

Pyrolysis gas chromatography- compares the polymeric make-up of paint binders

Automobile finishes- contain an electrocoat, primers, colorcoat and clearcoat



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Automobile finishes- contain an electrocoat, primers, colorcoat and clearcoat .

Layers determined by microscopy and spectroscopy.



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Paint Analysis

www.lincoln.ac.uk/fabs/archives/Odontology/TheLncshrAxeMurd.htm

Lincolnshire, UK - 1991-1993, two murders by axe.

Imprint of axe found on sofa and pillows. Axe found in local pond and paint

analysis by ICP-AES. Matches paint at crime scene.

Axe shape matches patterns found on sofa.

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Paint Analysis

The hand axe found by teenage boys out rowing on the lake in Boultham Park, Lincolnshire, pictured before the paint was scraped off. (Linconshire Police)





The cushion with blood stains of the axe head at A and B. (Linconshire Police)

www.lincoln.ac.uk/fabs/archives/Odontology/TheLncshrAxeMurd.htm

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Proper collection and preservation of paint evidence from an automobile suspected of being involved in hit-and-run incident. Paint that is foreign to the suspect automobile is observed on the hood.

1. Scrape the foreign paint as well as all underlying layers of paint off the car’s surface using a clean knife or scalpel. The scraping must clearly show the layer structure of the paint.

2. Obtain a control paint sample from an adjacent undamaged area of the car. Again, all layers must be included.

3. Package each paint specimen separately in a proper container. A druggist fold or a vial makes an excellent container.

4. Label all specimen containers. Evidence collector’s name or initials, the date, and the sampling location are to be shown. All items collected are to be described in the evidence collector’s field notes.

1 hair, fibers and paint che 113 forensic science copyright 2004-2006, james t. spencer

Documents

hair length

hair color

hair morphology slide

hair loss

hair coloring

hair growth anagen

hair structures medulla

exterior of hair shaft