New Patent XV

spheroids. The resulting mixed (hybrid) multi- cellular spheroids provide an in vivo-like en- vironment for the entrapped test cells. Test cells are subjected to treatment either before or after incorporation into spheroids, and the effect of such treatment is then evaluated from the colony forming ability of spheroids containing test cells.

~ 2 ~ 3 5

TREATMENT OF HAZARDOUS MATERIALS WITH AQUEOUS

AIR FOAM OF POLYHYDROXY POLYMER

Richard Stern assigned to Minnesota Mining and Manufacturing Company

5 ~ M 5 6

RADIATION DETECTOR SYSTEM

Lennar Claussen, Karlskoga, Sweden assigned to Aktiebolaget Sefors

A flame and radiation detector system is pro- vided with programmable logic to read the detec- tor and control the detector voltage supply in order to make possible a high counting rate. This makes the radiation detecting system fast and reliable by increasing the signal to noise ratio.

5025994

MEDICAL WASTE GRINDER

C Gene Maitlen, Simon G Franks assigned to Pelibe an OK Partnership

An apparatus for grinding hypodermic syringes or needles, IV needles and other medical waste into relatively fine particles. The apparatus in- cludes a housing having a case therein defining an inlet and an outlet. A plurality of rotors are disposed in the case, and each of the rotors has a plurality of radially outwardly extending teeth therein which interact with teeth on the other rotors to grind the syringes or needles. A dis- charge valve is provided for controlling the flow of particles discharged from the case. The teeth on the rotors are longitudinally and circumferen- tially spaced. Generally, the teeth on at least one of the rotors extend between the teeth on another of the rotors. Also, the teeth on at least a pair of the rotors have angled sides which are angled in opposite directions such that the angled sides of the teeth on one rotor generally face, and are aligned with, the corresponding angled sides of the teeth on the other rotor. Each of the teeth also has a first edge and an angled edge ex- tending at an angle with respect to the first edge.

A method of treating hazardous material or other substrate with an aqueous air foam, com- prising the steps of (1) preparing an aqueous solution or dispersion comprising (a) water- soluble polyhydroxy polymer having a plurality of hydrogen-bondable 1,2- and/or 1,3-diol struc- tures capable of complexation with the borate anion, B(OH)4-, (b) polyvalent ionic complexing agent, such as borax, which crosslinks said poly- mer by hydrogen-bonding complexation, (c) foaming agent to impart persistence to the fluid air foam generated upon aeration of said solu- tion or dispersion, (d) a pH modifier, such as sodium hydoxide or acetic acid, to impart an ap- propriate pH to the solution or dispersion neces- sary for time-controlled formation of gelled or viscous air foam from the fluid air foam, and (e) water as the major component of said aqueous solution or dispersion by weight; (2) aerating said aqueous solution or dispersion to form therefrom a fluid, aqueous, aerated or air- entrained, low density foam (or air foam) which is gelable or becomes viscous, generally at least 5 seconds after its formation; and (3) spraying, contacting or otherwise applying said fluid, aqueous air foam to exposed surface of said hazardous material or other substrate.

5 ~ 6 ~ 6

RADON MONITOR AND CONTROL SYSTEM BASED UPON

ALPHA PARTICLE DETECTION

George S Hurst assigned to Consultec Scientific Inc

A system for monitoring or controlling the level of radon in indoor air, based upon measuring al- pha particles due to the decay of radon or its daughter atoms. In one embodiment, the alpha particle decay of radon itself is detected and analyzed to control a vent in the heating and air conditioning system to automatically keep the radon level below a preselected level. In another embodiment, the daughter atoms 218Po and