Abstract: A semiconductor diode laser system with microwave mode locking. The system includes a semiconductor laser diode and an external reflector positioned to receive radiation that emits from the diode and reflects the same back into the diode, the microwave mode locking serving to modulate the radiation and the external reflector being properly positioned to return the radiation to the diode at a return time equal to the period of the drive signal or a submultiple thereof.
Type:
Grant
Filed:
November 9, 1983
Date of Patent:
August 7, 1984
Assignee:
Massachusetts Institute of Technology
Inventors:
Hermann A. Haus, Lance A. Glasser, Ping-Tong Ho
Abstract: A charge domain parallel processing network. The network includes a floating gate CCD tapped delay line and an array of CCD signal processors each including a charge domain digital-analog multiplier. The delay line holds and shifts analog sampled data in the form of charge packets. At each stage of the delay line a floating gate sensing electrode is coupled to an analog input of an associated one of the CCD signal processors. The sampled data in the respective delay line stages are transferred and subsequently processed in parallel in the processors. Within each processor, the computation functions are performed in the charge domain. In some forms, local charge domain accumulating memories accumulate and store the processed signals, for example, providing a matrix-matrix product network or providing a triple-matrix product network.
Abstract: A process for selectively etching an aluminum-containing coating in preference to a masking material on a surface of the aluminum-containing coating by positioning a patterned masking material on the aluminum-containing coating in a radio frequency plasma etching chamber and introducing an etchant gas and a source of oxygen and silicon to the interior of the chamber under conditions where silicon dioxide is deposited selectively on masking material layer while the unmasked aluminum-containing coating is etched.
Abstract: A multi-microelectrode has a plurality of sensing elements formed in a linear array along a face of a metal foil substrate. The foil substrate is sufficiently rigid and tough to have a very small volume along a needle length yet support the array of sensing elements and their leads. The preferred substrate materials are tungsten and molybdenum. The leads are insulated from the substrate and from the surrounding environment. A multi-microelectrode is supported in a microelectrode assembly by a connector which includes a guide channel on a support plate. Electrical contacts which may be conformable to the microelectrode are located in the guide channel, and the microelectrode is clamped against those contacts.
Abstract: This invention relates to the introduction of viable cells into a fibrous lattice by surgical, force-utilizing, or other manipulative techniques, all of which are referred to herein as "seeding." One embodiment comprises an autografting technique which involves intact tissue. Other embodiments which involve the distribution of an aqueous suspension of cells comprise centrifugal, spraying, pipetting and syringe emplacement. Each cell that survives the seeding process may reproduce into a colony of cells which grow until they reach confluence, thereby creating a uniform layer or volume of tissue. By proper placement of cells capable of generating such colonies, the period of recovery of a wound may be drastically reduced.
Abstract: A charge domain digital-analog multiplier device. The device has one analog input, M-parallel digital inputs, and one analog output. An M-bit digital word signal is applied to the digital inputs and an analog signal is applied to the analog input. The output is a charge packet which is proportional to the product of the analog input signal and the digital word.
Type:
Grant
Filed:
August 20, 1981
Date of Patent:
July 3, 1984
Assignee:
Massachusetts Institute of Technology
Inventors:
Barry E. Burke, Alice M. Chiang, William T. Lindley
Abstract: A collector apparatus and collection method for use with a blown-out seabottom wellhead. The collector apparatus, including a collector element with an extended, open base and an upper portion enclosing a volume to receive fluid (substantial quantities of gas and lesser quantities of oil) rising, in the water, from the wellhead, and a riser connected to the collector element and extending thereabove to conduct fluid therefrom, is characterized in that the collector element is adapted for fixable attachment to the ocean floor about the seabottom well head prior to any blow-out, and the upper portion of the collector element further includes a relief passage from its interior to the exterior of the collector apparatus, the release passage adapted to vent excess gas from the collector apparatus during initial stages of any blow-out.
Abstract: Certain agents are disclosed which promote growth of epithelial cells, including human epidermal cells. These agents are known to increase the level of cellular cyclic-AMP.
Type:
Grant
Filed:
December 1, 1980
Date of Patent:
June 26, 1984
Assignee:
President and Fellows of Harvard College
Abstract: In accordance with this invention, it has been found that the oxygen analog of 7-aminocephalosporanic acid and biologically active derivatives thereof can be formed from esters of 7-aminocephalosporanic acid. Esters of 7-oxocephalosporanic acid can be formed by diazotization of an ester of 7-aminocephalosporanic acid and contact of the diazo compound so formed with a hypohalous acid and a base in a water miscible organic solvent. Oxygen analogs of 7-aminocephalosporins isolated as esters are then formed by reducing the aforesaid ester to the corresponding 7.beta.-hydroxy-cephalosporanate and then forming the desired analog by introduction of a side chain via hydroxyl group modification. Oxygen analogs of 7-aminocephalosporins are then formed by regeneration of the acid via protective group removal.
Abstract: Choline or a natural or synthetic compound that dissociates to form choline is administered to a patient concomitantly with a drug in order to potentiate the effect of the drug by increasing acetylcholine levels in the brain or other tissues, and/or to suppress, or block the development of, unwanted side effects of the drug, by increasing acetylcholine levels in the brain or other tissues.
Abstract: Compositions containing controlled amounts of d,l-fenfluramine are administered to block the intermittent carbohydrate cravings without necessarily suppressing other food intakes.
Abstract: An electronically controlled rotating synchronous machine having armature and field windings on the same magnetically-permeable core. The rotor of the machine is an open tooth structure. The self inductance of the armature and field windings is substantially independent of relative position between the rotor and stator but mutual inductance between the armature and field windings varies with relative position. A rotor position detector senses the voltage in one of the machine windings and relates that voltage to said relative position. Switches are provided to control electric current flow in the armature winding on the basis of the voltage sensed by the detector.
Abstract: A process for preparing a crosslinked collagen-glycosaminoglycan composite material which comprises forming an uncrosslinked composite material from collagen and a glycosaminoglycan and contacting the uncrosslinked composite with a gaseous aldehyde until a crosslinked product having an M.sub.c of from about 800 to about 60,000 is disclosed along with composite materials prepared by this process. Artificial skin produced by this process is more stable toward long-term storage than similar materials prepared using other methods of crosslinking.
Abstract: A method for processing a polymer solution by changing the thermodynamic state of the solution to produce a dilute phase and a concentrated phase such that the thermodynamic state is sufficiently changed that the two phases are formed by spinodal decomposition.
Abstract: A photovoltaic-thermal solar cell including a semiconductor body having antireflective top and bottom surfaces and coated on each said surface with a patterned electrode covering less than 10% of the surface area. A thermal-absorbing surface is spaced apart from the bottom surface of the semiconductor and a heat-exchange fluid is passed between the bottom surface and the heat-absorbing surface.
Abstract: A method for the nondestructive testing and evaluation of insulating materials is disclosed. The method comprises applying an electrostatic charge pattern to one surface of the material; providing an electrode on a second surface opposite said one surface, said electrode being at an electrical potential lower than said one surface so that the electrostatic charge can decay through said material; allowing the charge pattern to decay for a predetermined period of time; and determining the residual charge pattern on said one surface after said period. The method preferably further comprises heating the material above room temperature which can enhance the results.
Abstract: Heparinase is produced by growing the bacterium, Flavobacterium heparinum in an improved defined medium consisting of a carbon source, two or more amino acids and several salts in the absence of protein. The carbon source concentration is specifically kept below a certain level to promote improved heparinase production. The sulfate source concentration is also specifically kept below a certain level to promote improved heparinase synthesis. Heparinase can be produced in this medium with or without the addition of an inducer compound.
Type:
Grant
Filed:
January 8, 1982
Date of Patent:
April 17, 1984
Assignee:
Massachusetts Institute of Technology
Inventors:
Robert S. Langer, Jr., Robert Linhardt, Charles L. Cooney, Parrish M. Galliher
Abstract: A correlation between gene amplification and tumor promotion is disclosed herein. This correlation allows for a simple cellular assay that indicates whether a substance or process is a tumor promoter. This assay does not depend upon numerous biochemical processes that introduce uncontrolled and unascertained varibles into other cellular assays. This assay can also be used to determine whether a set of cells is abnormally genetically labile and therefore susceptible to cancer or genetic disease.
Abstract: A selective-black absorber capable of operation at elevated temperatures and high efficiency as a solar energy absorber is described. A cermet of MgO/Au, MgO/Pt, and Cr.sub.2 O.sub.3 /Cr having high solar energy absorptance and low infrared energy emissivity is coated on a substrate having high infrared reflectivity such as Mo coated on stainless steel; Ni coated on Cu, or steel; aluminum, or steel. Typically an absorption coefficient of about 0.93 with an emissivity of about 0.09 is obtained and operation at a temperature of 300.degree.-400.degree. C. is possible depending on the cermet and substrate materials.
Abstract: A collector apparatus and method for use with a blown-out seabottom wellhead comprising a plurality of collector elements each having an extended, open base and an upper portion enclosing a volume to receive fluid comprising gas and lesser quantities of oil rising, in the water, from the wellhead, and risers connected to the collector elements and extending thereabove to conduct fluid therefrom. One collector element is disposed below at least one other collector element with an open volume defined therebetween, the first element positioned to intercept fluid rising from the wellhead, and the second element positioned to receive and collect excess flow of fluid that is not collected by the first element. A riser extends from the first collector element to the surface of the sea, and a second riser extends from the second collector element to a storage tank above the second collector element.