Abstract: Large diameter single crystals of aluminum nitride (AlN) are grown isotropically by injecting a nitrogen-containing gas into liquid aluminum at elevated temperatures. A seed crystal that is maintained at a temperature below that of the surrounding liquid aluminum is pulled from the melt, while the AlN that is formed in the melt is deposited on the seed crystal. An apparatus for carrying out the method is also disclosed.

Abstract: Synthetic gemstones are produced by growing single crystals of silicon carbide, fashioning the silicon carbide into gemstone cores, and thereafter depositing a thin coating of diamond on the core.

Abstract: A novel retroviral nucleotide sequence comprising a constitutive transport enhancer which functions to transport mRNA transcripts from the nucleus to the cytoplasm of a cell, wherein the mRNA transcript is either differentially spliced, alternatively spliced, incompletely spliced, or unspliced. Additionally disclosed are methods of using the constitutive transport enhancer to screen agents for antiviral activity against rev-dependent HIV proteins by expressing the proteins in a rev-negative subgenomic construct containing the enhancer either in the presence of absence of the agent.

Abstract: Bulk, low impurity aluminum nitride (AlN) single crystals are grown by sublimation or similar deposition techniques at growth rates greater than 0.5 mm/hr.

Abstract: Diamond gemstones and gemstones formed of crystals of silicon carbide are distinguished from each other by introducing a band of ultraviolet light into a target gemstone and measuring the transmissivity of that band of light by the gemstone. A diamond will transmit light within a certain band of the ultraviolet spectrum, while a silicon carbide gemstone will block light within this band. Several instruments for carrying out this procedure are described, including an instrument that utilizes a fiberoptic strand to convey ultraviolet light that has passed through the gemstone to a solid state photodetector.

Abstract: Synthetic gemstones having extraordinary brilliance and hardness are formed from large single crystals of relatively low impurity, translucent silicon carbide of a single polytype that are grown in a furnace sublimation system. The crystals are cut into rough gemstones that are thereafter fashioned into finished gemstones. A wide range of colors and shades is available by selective doping of the crystal during growth. A colorless gemstone is produced by growing the crystal undoped in a system substantially free of unwanted impurity atoms.

Abstract: Novel vectors are capable of producing MPMV (Mason-Pfizer Monkey Virus) proteins but not of packaging MPMV RNA, and the information about the packaging signal in MPMV and HIV can be used to create MPMV and HIV vectors that are capable of transferring foreign genes, e.g. for use in gene therapy.

Abstract: A high resolution, high brightness, full color display is provided having a liquid crystal pixel selectably addressable during a predetermined time period, a set of at least one red, one green, and one blue color light emitting diodes positioned adjacent the liquid crystal pixel for emitting light through the liquid crystal pixel, and means connected to the liquid crystal pixel for addressing the liquid crystal pixel a plurality of times during the predetermined time period for each color so as to provide persistence when changes in color are perceived by the human eye.

Abstract: Synthetic gemstones having extraordinary brilliance and hardness are formed from large single crystals of relatively low impurity, translucent silicon carbide of a single polytype that are grown in a furnace sublimation system. The crystals are cut into rough gemstones that are thereafter fashioned into finished gemstones. A wide range of colors and shades is available by selective doping of the crystal during growth. A colorless gemstone is produced by growing the crystal undoped in a system substantially free of unwanted impurity atoms.

Abstract: A novel retroviral nucleotide sequence comprising a constitutive transport enhancer which functions to transport mRNA transcripts from the nucleus to the cytoplasm of a cell, wherein the mRNA transcript is either differentially spliced, alternatively spliced, incompletely spliced, or unspliced. Also disclosed is a recombinant attenuated HIV containing only structural proteins gag, pol, and env, wherein the expression of the structural proteins is rev-independent and facilitated by the constitutive transport enhancer.

Abstract: A high resolution, full color display is provided having a liquid crystal pixel selectably addressable during a predetermined time period, a set of at least one red, one green and one blue color light source adjacent the liquid crystal pixel for emitting light through the liquid crystal pixel, and means for addressing the liquid crystal pixel a plurality of times during the predetermined time period for each color so as to provide persistence when changes in color are perceived by the human eye. A method of producing a high resolution, full color display is also provided by lighting a set of one red, one green, and one blue light sources by lighting the respective colored light sources for a predetermined time period for each color and shuttering the set of light sources with a liquid crystal pixel for at least a portion of the predetermined time period to thereby emit light from the shuttered pixel for a selected time period so as to provide persistence when changes in color are perceived by the human eye.

Abstract: A pond for the storage of hazardous materials, such as irradiated nuclear fuel elements, under water. Upper (8) and lower (6) impervious membranes extend without interruption beneath the floor (1) of the pond and the edges of the membranes lead into a trench (9) surrounding the pond. Any leakage through the floor is directed normally by the upper membrane (8) into the trench (9). The lower membrane (6) provides an additional impervious barrier in the event of a leak in the upper membrane (8) and again directs the leakage into the trench thereby avoiding contamination of the ground beneath the pond.

Abstract: In the extrusion of a material, which can be a metal feedstock, through a die means by maintaining frictional engagement of the material with passageway defining surfaces of a member which is moved towards the die means such that frictional drag of the passageway defining surfaces urges the material through the die means, the improvement of enhancing the resultant available extrusion force by either increasing said frictional drag or reducing the frictional resistance to movement of said material relative to non-moving parts of said passageway, or a combination of both.

Abstract: Apparatus for performing extrusion has a rotatable wheel member with an endless groove in its periphery, a second member fixed relative to the wheel member and co-operating therewith to define a passageway therebetween, an abutment member fixed relative to the wheel member and projecting into said groove to block it, die orifice means associated positionally with said abutment member and leading from said passageway, and means for prestressing the material constituting at least the walls of the endless groove for avoiding any fatigue failure problems of the wheel member.

Abstract: An apparatus and a method are provided for assembling micro-filter units having a barrel, a plug adapted to be inserted in the barrel, and a filter disc clamped between the barrel and the plug, which are characterized in that the filter disc is punched out and seated in the barrel in a single stroke of a punch.

Abstract: Microliter sized samples of filtered urine or the like are obtained by taking up a few drops of urine into a bulb-type micro-syringe inserting the nozzle thereof tightly into the inlet passageway of a micro-filter having a disc of filter paper as the filtering medium held firmly between the inlet passageway and an outlet passageway and squeezing the bulb of the micro-syringe to force the urine through the filter paper. The outlet passageway is constricted in size and shape to discharge the filtered urine in drops. The filtered urine then comes through in uniform drops of predetermined size which are utilized in a testing procedure, for example, in a direct agglutination test for pregnancy.

Abstract: An apparatus and a method are provided for assembling micro-filter units having a barrel, a plug adapted to be inserted in the barrel, and a filter disc clamped between the barrel and the plug, which are characterized in that the filter disc is punched out and seated in the barrel in a single stroke of a punch.