Abstract: An apparatus for removing material from a biological solution consisting of a reactor chamber having an inlet and an outlet, a bioactive compound immobilized on particular supports within the reactor, means for retaining the particular supports within the reactor, means for recirculating the solution and the supports at a high flow rate within the reactor, and means for agitating or dispersing the recirculating solution-support mixture throughout the reactor chamber so as to prevent packing of the supports while not subjecting the solution to excessive or damaging forces.In the given example, an apparatus for the extracorporeal removal of heparin from blood is provided. Heparinase is immobilized on cross-linked agarose beads recirculated at a high flow rate through the reactor. Agitation of the blood-bead mixture sufficient to prevent packing of the beads within the reactor chamber is provided by means of a series of openings in the recirculation tube dispersing the mixture throughout the chamber.

Abstract: An antigen delivery system utilizing a biodegradable polymer with good mechanical properties in combination with a material stimulating the immune system. The material having adjuvant activity may be polymer degradation products or an adjuvant which is contained within or bound to the polymer. In one embodiment, the polymer is formed from tyrosine dipeptides. Poly(CTTH-iminocarbonate) is a preferred tyrosine dipeptide polymer for constructing implantable delivery systems for antigenic material. The polymer is not an adjuvant in itself but degrades into products which stimulate the immune system. The tyrosine dipeptide can also be used as a conventional adjuvant.

Abstract: A technique for producing a cold environment wherein warm fluid, e.g. at room temperature, from a compressor, is introduced under pressure into an input channel which is directly coupled to a displacement volume, the fluid being precooled in the input channel to a temperature lower than that of the input fluid. Fluid in the inner channel at or near the displacement volume is periodically pressurized to a high pressure. The displacement volume is then expanded so that the high pressure fluid flowing into the expanded volume is decreased from such high pressure to a substantially lower pressure, the temperature thereof being reduced to a substantially lower temperature for producing the cold environment. The low pressure, low temperature fluid flows into an output channel, preferably via a suitable valve and surge volume, for flow in the output channel at a substantially constant pressure.

Abstract: Light from a master laser is divided into multiple beams. Each of the beams is imaged onto a slave laser in a slave laser array. The multiple beams injection lock the frequency of each laser in the slave laser array to the frequency of the master laser. Some of the output light from the array of slave lasers is directed onto an optical wavefront measurement sensor which measures spatial variation in light phase and intensity. A computer responsive to the output of the optical wavefront measurement sensor controls the injection current to each laser in the slave laser array to adjust dynamically the relative phase of each laser in the array so as to synthesize a desired wavefront.

Abstract: A single step method for preparation of multi-layer polymeric delivery systems. Any two or three different degradable or non-degradable polymers which are not soluble in each other at a particular concentration, as dictated by their phase diagram, can be used. The multi-layer microcapsules produced by the method are distinguished by extremely uniform dimensioned layers of polymer and actual incorporation of the substance to be delivered into the polymer layers.In the preferred embodiment of the method, two polymers are dissolved in a volatile organic solvent, the substance to be encapsulated is dispersed or dissolved in the polymer solution, the mixture is suspended in an aqueous solution and stirred, and the solvent is slowly evaporated, creating microspheres with an inner core formed by one polymer and an outer layer formed by the second polymer. In another embodiment one polymer may be formed within a layer of the other polymer by increasing the rate of evaporation of the volatile solvent.

Abstract: Malfunctions of the cardiovascular control system may be diagnosed by examination of a patient's heart rate fluctuation power spectra. Particularly indicative of cardiovascular stress are: a level below about 0.1 (beats/min.).sup.2 in the power spectrum of heart rate fluctuations at a frequency between about 0.04 and about 0.10 Hz; a marked increase to above about 10 (beats/min.).sup.2 in a peak in the heart rate fluctuation power spectrum between about 0.04 to 0.10 Hz; and a ratio of the area under a heart rate power spectrum peak at a frequency between about 0.04 and 0.10 Hz to the area under a peak in the respiratory heart rate fluctuation power spectrum centered at the mean respiratory rate about about 0.10 Hz as having an absolute value less than 2.0 for longer than or equal to about one hour or as having an absolute value greater than about 50.

Abstract: Thermal conductivity, thermal diffusivity and/or fluid perfusion within a medium such as cutaneous tissue is non-invasively measured by at least two heating and temperature sensor. One sensor is positioned in thermal communication with the medium and a second sensor is positioned thermal communication with the first sensor. Both sensor are heated (or cooled) so as to substantially prevent net heat flow between them. In this manner, net heat flow between the first sensor and the medium can be measured, which measurements allow determination of the thermal conductivity, thermal diffusivity and/or fluid perfusion within the medium.

Abstract: A solid state gain medium is disposed between two mirrors to form a resonant cavity, the cavity length selected so that the gain bandwidth of the gain medium is less than the frequency separation of the cavity modes. By selecting this cavity length, only a single longitudinal mode will oscillate when the laser operates in a single transverse mode. The microlaser is optically pumped by any appropriate source such as a semiconductor injection laser or laser array. Suitable gain media are Nd:YAG and Nd pentaphosphate.

Abstract: The present invention comprises a circuit for measuring the capacitive differences of small capacitors. The circuit comprises a reference capacitor and a sensor capacitor. Connected to one of the plates of each capacitor is a switch which connects the capacitors to one of two reference voltages. The other plate of the capacitors are connected to an input terminal of a voltage comparator. The comparator compares the input voltage with a third reference voltage. Differences in voltages detected by the comparator are applied to a feedback loop for generating an offset voltage at the input terminal. The offset voltage applied at the input terminal is proportional to the capacitive difference between the reference capacitor and the sensor capacitor. The feedback loop comprises a successive approximation register for digitizing the offset voltages and a digital to analog converter for converting the digitized voltages into analog voltages which are applied at the input terminal.

Abstract: An affinity matrix and a method for the detection of low molecular weight compositions such as aflatoxins are provided utilizing specific monoclonal IgM antibody having an affinity constant not less than about 1.times.10.sup.9 liters per mole. Methods for the preparation and use of such affinity matrices are also given. The detection is rapid, accurate, reproducible, and allows for quantitative recovery of the composition of interest.

Abstract: The control system includes a master loop for controlling crystal interface diameter and slave control loops for controlling the melt and the crystal thermal environment. Diameter and meniscus angle signals are partitioned into both a low frequency and a high frequency signal. The low frequency signal is used to adjust the set point of the melt. The higher frequency signal is used to control the crystal pull rate. The crystal control slave loop regulates crystal heat flux which may include following a heat flux trajectory. The heat flux trajectory may also be used to adjust the melt temperature set point.

Abstract: Polyanhydrides with uniform distribution of alkyl and aromatic residues are prepared by melt polycondensation or solution polymerization of p-carboxyphenoxyalkanoic acids or p-carboxyphenylalkanoic acids. These polymers are soluble in common organic solvents and have low melting points, generally in the range of 40.degree.-100.degree. C.The polyanhydrides are especially well suited for forming bioerodible matrices in controlled bioactive compound delivery devices. A polymeric matrix formed according to the method described here degrades uniformly during drug release, preventing the wholescale channeling of the bioactive compound into the environment, and eliminating the problem of the presence of the polymer matrix at the site long after drug release. The polymer displays zero-order kinetic degradation profiles over various periods of time (days to months), at a rate useful for controlled drug delivery.

Abstract: A non-intrusive monitor of energy consumption of residential appliances is described in which sensors, coupled to the power circuits entering a residence, supply analog voltage and current signals which are converted to digital format and processed to detect changes in certain residential load parameters, i.e., admittance. Cluster analysis techniques are employed to group change measurements into certain categories, and logic is applied to identify individual appliances and the energy consumed by each.

Abstract: Methods and devices for characterizing tissues and the like utilize signals obtained from ultrasonic backscatter processes. The method accounts for frequency-dependent attenuation, spatially-varying media statistics, arbitrary beam geometries, and arbitrary pulse shapes. Statistical analysis is employed to estimate the scatterer number density (SND) of tissues. The method for estimating the scatterer number density incorporates measurements of both the statistical moments of the backscattered signals and the point spread function of the acoustic system.

Abstract: A lower threshold for dynamic range compression and clipping is allowed by sinusoidal estimation and phase adjustment of the original speech signal to obtain a lower Peak to RMS ratio. A sinusoidal speech representation system is applied to the problem of speech dispersion by pre-processing the waveform prior to transmission to reduce the peak-to-RMS ratio of the waveform. The sinusoidal system first estimates and then removes the natural phase dispersion in the frequency components of the speech signal. Artificial dispersion based on pulse compression techniques is then introduced with little change in speech quality. The new phase dispersion allocation serves to preprocess the waveform prior to dynamic range compression and clipping, allowing considerably deeper thresholding than can be tolerated on the original waveform.

Abstract: A method and apparatus for forming tapered thickness and material content of III-V material, or alloys thereof, in particular GaAs and AlGaAs, by gradient thermal heating of substrates during epitaxial growth and the optoelectronic structures formed thereby.

Abstract: A recording system for representing digital information in the form of marks and the absence of marks at a plurality of locations, each mark being formed in response to energy delivered by an optical beam; the device includes a material configured in a form to receive the beam at selected locations for forming the marks, the material being characterized by undergoing pyrolysis to form the marks at the selected locations in response to the energy.

Abstract: A process for etching polytetrafluoroethylene (PTFE) is disclosed herein which comprises defluorinating the surface layer of PTFE. The process includes exposing a sample of PTFE to the vapors of an alkali metal such that a layer of the fluoride of the alkali metal is formed on the surface of the PTFE sample and removing the fluoride of the alkali metal from the surface of the PTFE sample.

Abstract: Composite materials and methods for making such materials are disclosed in which dispersed ceramic particles are at chemical equilibrium with a base metal matrix, thereby permitting such materials to be remelted and subsequently cast or otherwise processed to form net weight parts and other finished (or semi-finished) articles while maintaining the microstructure and mechanical properties (e.g. wear resistance or hardness) of the original composite. The composite materials of the present invention are composed of ceramic particles in a base metal matrix. The ceramics are preferably carbides of titanium, zirconium, tungsten, molybdenum or other refractory metals. The base metal can be iron, nickel, cobalt, chromium or other high temperature metal and alloys thereof. For ferrous matrices, alloys suitable for use as the base metal include cast iron, carbon steels, stainless steels and iron-based superalloys.

Abstract: Light reflected from a three-dimensional scene is sequentially scanned according to its direction as it passes through a window. At any given time only light traveling in one direction can pass through the window to be recorded. These sequentially recorded collimated views can be recorded, altered, transmitted, and displayed as desired. The views are displayed through a synchronized directional scanner which sequentially displays the views through respective angles, providing a scene with parallax as well as depth. The directional scanner may be a louver structure or a device for steering a collimated display.