Abstract: A method of producing 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) by nitrosation of 1,3-bis(2-chloroethyl)-urea utilizing as a nitrosating agent dinitrogen trioxide (N.sub.2 O.sub.3) in molar excess of theoretical wherein the molar excess of N.sub.2 O.sub.3 ranges from 10-200% and preferably from 10-20%. The nitrosation reaction is conventionally carried out in the cold from 0.degree. C to -20.degree. C and a non-aqueous solvent is utilized. The preferred non-aqueous solvent is of the chlorinated variety; i.e., methylene dichloride. Other preferred solvents include related halogenated compounds such as ethylene dichloride, nitro-compounds such as nitromethane, acetonitrile, and simple ethers such as ethyl ether. Other less preferred but operable compounds include esters such as ethyl acetate, simple ketones such as acetones, and chloroform.

Abstract: An apparatus for low temperature ashing of specimens is provided. The specimens to be ashed are first freeze dried and then reduced to an ash by a radio frequency (RF) excited gas plasma in a device which includes a reaction chamber, means to reduce the pressure in the chamber, means communicating with the chamber for supplying a stream of reaction gas thereto, and an RF means including a driven and receiver antenna pair with an annular antenna around the chamber and a planer antenna associated with the end wall of the chamber.

Abstract: A uterine caliper and sound consisting of an elongated body having outwardly biased resilient caliper wings and a spring-loaded slidable cervical stop. A slide on the body is operatively connected to the wings by a monofilament and operates with respect to a first scale on the body as a width indicator. A rod extending longitudinally on the body is connected to the cervical stop and cooperates with a second scale on the body as a depth indicator. The instrument can be positioned to measure the distance from the outer cervical ostium to the fundus, as read on said second scale. The wings may be allowed to open by moving the slide, and when the wings engage the utero-tubal junctions, the width may be read on said first scale. By adjustment of the caliper wings the instrument may be retracted until the resistance of the inner ostium of the cervix is felt, enabling the length of the cervical canal to be read directly by the position of the longitudinal indicator rod with respect to said second scale.

Abstract: A hard, clear, glassy, smooth polymer with a dry surface having a dye precursor therein which forms a permanent color at those areas of the solid polymer that have been irradiated with ultra-violet or ionizing radiation is formed by combining vinyl and/or acrylic monomers, a triphenylmethane cyanide dye precursor and a chemical initiator that is compatible with the dye cyanide and polymerizing in the presence of a slight excess of hydrogen ions in an inert atmosphere.

Abstract: A method and apparatus for the fractionation of centrifuged density gradients have been developed. The apparatus consists of a gradient holder composed of a transparent and an opaque section which contains an opening allowing a centrifuged tube containing a density gradient having individual bands to be inserted into the holder. A displaceable piston which is suspended above the holder and is connected to an actuator may be raised or lowered into the density gradient. A standard illuminating device is placed under the gradient holder so that the exact position of each individual band can be determined. Once the precise location is determined, the displaceable piston is lowered into the gradient and by operating the actuator, the desired band of gradient can be extracted. Additionally, this method may be utilized in a continuous fractionation of the entire gradient.

Abstract: An apparatus for performing countercurrent chromatography comprises a rotor which holds a coiled helix column at 30.degree. from the vertical. Versatility of the angle rotor is demonstrated on high efficiency separations of biological compounds using a variety of two-phase solvent systems.

Abstract: The method of utilizing .alpha.,.beta.-unsaturated amino acids, acyl, and N-acyl derivatives as linking agents in the solid phase synthesis of peptides with the corresponding production of carboxyl terminal amides. Preferred unsaturated amino acids are dehydroalanine and dehydrobutyrine which are constituents in naturally occurring amides such as nisin and subtilin. The synthesis follows conventional lines of R. B. Merrifield et al including blocking of the amino nitrogen, with the exception that the release agent contains an amount of water equimolar to the reactant .alpha.,.beta.-unsaturated amino acid.

Abstract: An apparatus for determining the composition of a gas by measuring the acoustic impedence and absorption of a gas at two distinct frequencies. The velocity variations due to the presence of a gas in a fixed length column are measured by comparing the phase of the voltage applied to a sending transducer to the phase of the voltage in a receiving transducer. Since the distance between the transducers is fixed, the phase variation is indicative of the velocity of the sound at any particular frequency. The output voltage obtained from a phase comparator is proportional to the phase difference and since the relationship between the concentration of the gas and the output voltage is known, the concentration of the gas is easily ascertained. The influence of temperature changes in the column are eliminated by summing the phase differences measured at the two distinct frequencies. In addition, by a judicious choice of frequencies, the amount of water vapor present in a particular gas may be compensated for.

Abstract: A blink-activated duct for supplying a solution to the eye of the user has a particular utility in introducing an artificial tear solution to the eye of those persons who are incapable of producing such a solution themselves. The duct consists of a reservoir section which contains the solution, and a pump section consisting of a contact lens or a Silastic tube assembly for delivering the solution directly to the eye. This pump section is activated by the eyelid compressing the contact lens or the Silastic tube assembly, causing the solution to be displaced to the eye and successively drawing additional solution from the reservoir section to the pump section due to the creation of a temporary vacuum.

Abstract: A safety apparatus for use in administering radioactive serums by a syringe, without endangering the health and safety of the medical operators, consists of a sheath and a shield which can be retracted into the sheath to assay the radioactive serum in an assay well. The shield can be moved from the retracted position into an extended position when the serum is to be injected into the patient. To protect the operator, the shield can be constructed of tantalum or any like high density substance to attenuate the radiation, emanating from the radioactive serums contained in the syringe, from passing to the atmosphere. A lead glass window is provided so that the operator can determine the exact quantity of the radioactive serum which is contained in the syringe.

Abstract: Addition of ammonium stabilized colloidal silica, borax and boric acid to the distilled water in which dental porcelain is fired greatly increases the firing range by reducing "balling" or edge rounding, and flow deformation. Greatly increased machinability and indefinitely prolonged green-biscuit strength is also obtained by the use the present additive without deleterious effects on the porcelain.

Abstract: A feed hopper for the cage of a laboratory mouse comprises a substantially rectangular parallelepiped feed chamber containing an open top. A wire mesh base screen is affixed to at least one front surface of the chamber, having a top portion of the wire screen fastened at an angle with respect to the plane of that front surface, and a bottom portion of the screen parallel to the plane of the open top of the feeder. Feed which is to be ingested by the mouse rests on the base wire screen which has been designed in such a manner that the weight of the feed is forced to collapse as the animal consumes the feed, thus providing a continual flow and availability of feed. Furthermore, the sides of the wire mesh openings are such that commercially available, autoclavable mash feed could be used. The mouse feeds by moving its tongue over the screen to pick up food particles thereon.

Abstract: A radiation measuring instrument including a fast charge digitizer and a digital data acquisition system has been developed. The fast charge digitizer includes a charge integrator connected to a conventional ionization chamber which generates an output current in proportion to ionizing radiation exposure rate. The charge integrator has an output connected to a comparator which is switched from a high state to a low state when the output of the integrator goes above the comparator threshold. The comparator output is connected to a bistable multivibrator consisting of two non-retriggerable one shot multivibrators connected in a feedback configuration. As long as the comparator output is in the low state, the bistable multivibrator generates a train of pluses which are fed back through an analog switch and a high megohm resistance to the input of the integrator.

Abstract: A method and apparatus for cutting cylinders of gelatinous material such as polyacrylamide gels into discs of precise thickness comprises a cutting surface which is placed in contact with the entire circumference of the cylinder. Cutting force is then applied from all points on the circumference at once, resulting in cutting the gel cylinder towards the center from all points on the circumference. This is accomplished by the use of a multi-bladed diaphragm similar to an iris diaphragm used for camera aperture control. The edges of the blades of the diaphragm form a variable dimension cutting surface.

Abstract: An apparatus for time delay acoustic spectrographic analysis of fluid composition uses frequency modulated ultrasonic vibrations which are transmitted through the fluid from a sending transducer to a receiving transducer. By scanning the frequency of the modulated vibrations at a sufficiently high rate, standing waves which give erroneous indications of fluid component concentrations, are eliminated. The frequency of the signal at the sending transducer is compared with that at the receiving transducer and a comparing means whose output is related to the frequency difference of the signal at the receiving transducer from the sending transducer measures the number of times this signal shifts 360.degree. during a scanning period. This measurement is directly related to a property of the fluid being measured. The method and apparatus have particular application in the investigation of coagulation in human blood.