Abstract: The disclosed BTSC encoder includes a left high pass filter means for receiving a digital left channel audio signal and for digitally high pass filtering the digital left channel audio signal and thereby generating a digital left filtered signal; a right high pass filter means for receiving a digital right channel audio signal and for digitally high pass filtering the digital right channel audio signal and thereby generating a digital right filtered signal; a matrix means for receiving the digital left and digital right filtered signals, and including means for summing the digital left and digital right filtered signals and thereby generating a digital sum signal, and including means for subtracting one of the digital left and digital right filtered signals from the other of the digital left and digital right filtered signals and thereby generating a digital difference signal; a difference channel processing means for digitally processing the digital difference signal; and a sum channel processing means for d

Abstract: High pressure liquid chromatographic apparatus in which a fluid mixture containing at least one solute that is reactive with chromatographically reactive surfaces in the column is loaded into the column, and a number of plugs of different eluant fluids are injected into that column. The injections are made in a manner that minimizes the amount of eluant required. In one embodiment, the injections are made to insure that flow of at least the eluant fluids through the column will occur, preferably with a substantially flat wave front, at speeds corresponding to reduced velocities greater than about 5,000, i.e. at flow rates sufficient to induce turbulent flow in those fluids, thereby minimizing the time required for the entire succession of mixture and eluant fluids to traverse the column.

Abstract: Disclosed is a method of reducing or inhibiting the tumorigenicity of a tumor cell in which a vector including a nucleotide sequence encoding a differentiation factor receptor, or a polypeptide portion thereof, is transferred to the tumor cell such that the nucleotide sequence is expressed. Tumorigenicity is monitored by cell growth and colony formation in a semi-soft medium, a reduction in proliferation being indicative of the reduction or inhibition of tumorigenicity of the treated tumor cell.

Abstract: The invention relates to the efficient coding of packetized binary (NRZ) data, for example Ethernet packets, over a binary channel. Since Ethernet packetized data has three states (0, 1, and Idle), the theoretical bandwidth required for transmission, assuming completely random packets of arbitrary length and arbitrary interpacket idle periods, i.e. gaps, is 1.585 the data rate. The invention uses the information that both packets and gaps have predetermined minimum lengths constructs more efficient codes. In particular, a coding scheme is shown that provides in two states signal requiring a bandwidth of only 1.25 the three state signal data rate.

Abstract: The invention provides an apparatus for measuring the flying height and orientation of a magnetic head (54) relative to a transparent disk (20) based on frustrated total internal reflection. The apparatus comprises a housing (10) that mounts an electric motor (12) which rotationally supports the aforementioned disk. The disk (20) has a tapered lateral surface (20c) with light emitting means (22) such as a laser(24) installed on one side of the disk lateral surface and a light detecting means (30) on a side of the disk diametrically opposite to the laser. The light is emitted from the laser (24) and is directed to the disk (20) perpendicular to the tapered lateral surface (20c) of the disk (20). The latter has a tapering angle of 45.degree. so that the light is propagated through the body of the disk (20) in the channel region (49) with total internal reflection from two parallel surfaces (20a and 20b) of the disk into the body of the disk.

Abstract: The invention provides an article of manufacture comprising a substantially non-immunogenic articular cartilage heterograft for implantation into humans. The invention further provides a method for preparing an articular cartilage heterograft by removing at least a portion of an articular cartilage from a non-human animal to provide a heterograft; washing the heterograft in saline and alcohol; subjecting the heterograft to at least one treatment selected from the group consisting of exposure to ultraviolet radiation, immersion in alcohol, ozonation, freeze/thaw cycling, and optionally to chemical crosslinking. In accordance with the invention the heterograft has substantially the same mechanical properties as the native xenogeneic articular cartilage.

Abstract: In an x-ray scanning system having an x-ray source and an x-ray detector assembly, including a plurality of x-ray detector crystals grouped in substantially linear arrays and cooperative with the x-ray source, a substantially continuous radiation detection zone is established by positioning the detector arrays so that substantially all radiation from the source passing through the detector assembly passes through at least a portion of at least one detector crystal. The detector arrays are tilted at a preselected angle .alpha. with respect to a nominally perpendicular orientation relative to radial lines extending from the focal spot, so that the spaces between adjacent detector crystals in an array are not aligned with x-rays emanating from the x-ray source. The angle .alpha. is a function of the geometry of the detector crystals and the spaces between adjacent crystals in an array.

Abstract: An instrument holder configured so as to fit around the neck of the user and engage a portion of the chest, allowing the user to support the instrument without clenching the instrument between the chin and shoulder as is now customary. The invention further includes an attaching mechanism that allows the user to easily attach and detach the violin from the supporting brace assembly. The device is of low profile and can be designed to easily fit in a case alongside the instrument. It is of simple construction and is an improvement over the prior art.

Abstract: Disclosed is a method of selecting for a compound which modulates the behavior of an insect. In this method, electrical characteristics of an insect chemoreceptor neuron in the presence of control stimulation, then a known chemical modulator of insect activity, and then a test compound are measured after the neuron is contacted therewith. These measurements are compared and the test compound classified based on this comparison.

Abstract: Layered carbon-carbon composites having improved interlaminar tensile strength are disclosed together with a process for making such composites. A metal catalyst is first deposited on a panel comprising a plurality of layers of carbon fiber cloth. The panel is then exposed to a gaseous hydrocarbon in an inert atmosphere at elevated temperature in order to promote the growth of graphite whiskers between the carbon cloth layers.

Abstract: In an improved CT scanner calibration method and apparatus, a radiation beam, for example an x-ray beam, is directed at a plurality of radiation detectors. The beam is attenuated by a phantom of known attenuation characteristics. The detectors generate measured attenuation data from the attenuated beam. The measured attenuation data is back-projected to generate a measured phantom image. The measured phantom image is converted to an ideal phantom image. The ideal phantom image is forward projected to generate ideal attenuation data. Calibration values for each detector channel in the scanner are generated by cross-referencing the ideal and measured attenuation data. In a preferred embodiment, this cross-referenced data is compressed and stored in a look-up table for referencing during later interrogation of subjects.

Abstract: A method of and apparatus for liquid chromatography at improved analytical and preparative speeds and quantities involves flow of fluids through the column at flow rates sufficient to induce turbulent flow in those fluids. In one embodiment, the apparatus and method includes a substantially uniform chromatography column created by packing together a multiplicity of rigid, solid, porous particles having diameters of not less than about 30 .mu.m, surfaces of the particles being chromatographically active. A fluid mixture containing at least one solute that is reactive with the particle surfaces is injected into the column and subsequently eluted therefrom by a eluant fluid flow, both the injection and elution being effected at a velocity sufficient to induce flow within at least a substantial portion of the interstitial volume between the particles at a reduced velocity greater than about 5,000.

Abstract: An interactive learning system is disclosed that includes a note-making facility, a mentor facility, and an editor facility as its major subsystems. The note-making facility allows the user to create notes while scanning through an electronic text file that is accessible from a suitable memory space. The mentor facility provides content-specific information in response to the selection of certain passages or quotations from the text file by the user. The editor facility provides generalized learning strategies and recommendations useful in the analysis of text and the preparation of a written report. The information provided by the editor facility is generalized, and hence is not specific to the current text file; in contrast, the mentor facility is content-specific, and furnishes the user with information that is specifically related to the text under review.

Abstract: An instrument and kit for harvesting a bone-patella tendon-bone (BTB) graft having substantially cylindrical bone plugs, and a method for harvesting a BTB graft. The instrument comprises two cylindrical shell portions extending along an axis from a drive end to a cutting end. One of the shell portions, which is positionable around a portion of the tendon, includes an axial slot which permits the graft portion of the tendon to extend therethrough. The shell portions interlock together in a hinged and mutually biased engagement to form a cylindrical tube around the graft portion, with a cutting edge that extends a full 360 degrees about the axis of rotation. Bone plugs obtained using the instrument are fully circular in cross-section for substantially their entire length.

Abstract: A scanning tomography system has a gantry including a disk for supporting a X-ray source and detector array and rotatable about a central axis. Multiple scans are made to reduce the effects of motion artifacts and improve image quality. In addition, the detector array is supported by a suspension system and is movable about the focal spot of the X-ray source a small amount so that in one mode of operation the detector array can be shifted at a predetermined angle from one position to at least one other position during a scan so as to provide an increase in the number of unique X-ray paths so as to provide improved image quality. In a second mode of operation, the detector array can be offset from the center ray so as to provide a quarter of a detector offset.

Abstract: The surface of an acoustic reflector faces the source, and has a plurality (N) of wells, where N is an odd prime number. Each well has a depth D.sub.n =(n.sup.2 rem N)* unit depth (0<=N<=N-1), governed by a Quadratic Residue Sequence. Acoustic energy directed from the source to the reflector, and reflected along a length direction of the reflector, has substantially equal acoustic energy in all angular directions from the reflector within plus and minus .pi./2 from the direction of radiation. The surface above can be used for the surface of a loudspeaker, where either it is the surface of the loudspeaker or has speakers positioned at the bottom of the wells. The surface above can also be used for drag reduction in moving vehicles when it is positioned either at the front or rear of the vehicle.

Abstract: The invention is an autozero compensator for use in processing low level signals, the compensator comprising an input integrating operational amplifier providing at its output in one mode an error signal responsively to offset voltage across the differential input terminals of the amplifier. A second amplifier is provided in a feedback loop for generating from the error signal a charge at a compensating voltage equal and opposite to the offset voltage. That charge is capacitively stored and applied to the input amplifier to cancel the offset voltage.

Abstract: In an x-ray scanning system having an x-ray source and a plurality of x-ray detectors mounted in substantially linear arrays and positioned along an arc extending about a focal spot defined by the x-ray source, the placement of the arrays along the arc is optimized to substantially avoid interfering contact between adjacent arrays. Each detector array is located at a preselected radial distance from the focal spot and oriented at a preselected angle with respect to radial lines extending from the focal spot so that the radiation-insensitive end portions of adjacent arrays overlap in the tangential direction. The tangential spacing between adjacent detector arrays is thus approximately equal to the tangential spacing between adjacent detectors in a single array.

Abstract: A ventilated garment is provided having at least one substantially non-stretchable front panel and at least one rear panel, in which the front and rear panels have an opening therein, and in which the front panel includes a substantially non-stretchable, air permeable, vent panel, having a shape substantially corresponding to the front panel opening, affixed to the front panel along the periphery of the front panel opening. The front panel further includes a cover element having a shape substantially corresponding to the front panel opening. A first portion of the cover element periphery is affixed to the front panel substantially along a first portion of the periphery of the front panel opening.

Abstract: Solid state optically coupled power switch with light induced or modified voltage applied or removed at one or more MOSFET gate and source electrode pairs to shift each MOSFET between its high and low impedance states and in various circuit arrays for ac or dc switching and/or cross points switching or mechanical Form C relay substitution or other purposes