Abstract: A cryptographic communications system and method. The system includes a communications channel coupled to at least one terminal having an encoding device and to at least one terminal having a decoding device. A message-to-be-transferred is enciphered to ciphertext at the encoding terminal by first encoding the message as a number M in a predetermined set, and then raising that number to a first predetermined power (associated with the intended receiver) and finally computing the remainder, or residue, C, when the exponentiated number is divided by the product of two predetermined prime numbers (associated with the intended receiver). The residue C is the ciphertext.
Type:
Grant
Filed:
December 14, 1977
Date of Patent:
September 20, 1983
Assignee:
Massachusetts Institute of Technology
Inventors:
Ronald L. Rivest, Adi Shamir, Leonard M. Adleman
Abstract: The level of glycine in the brain and in the spinal cord is regulated by administering a neutral amino acid composition to a human wherein increased or decreased brain and spinal cord levels of glycine is effected when the composition contains increased or decreased amounts of threonine or a precursor of L-threonine. The neutral amino acid composition can be administered alone or concomitantly with a drug which either has the undesirable side effect of suppressing glycine-mediated neurotransmission or whose therapeutic efficacy is enhanced by increasing glycinergic neurotransmission.
Abstract: Chiral boron enolates are provided having the formulae: ##STR1## wherein R.sub.2 B is 9-borobicyclo[3.3.1]non-9-yl(BBN) or R is n-butyl, cyclopentyl, or another alkyl group.The boron enolates can be condensed with aldehydes to produce aldol stereospecific product which includes a .beta.-hydroxy-.alpha.-methyl carbonyl unit in the product structure.
Abstract: Polymers having a substantially completely fluorinated surface of low surface energy and substantially free of oxygen and having a thickness up to about 200 Angstroms, the remainder of the polymer comprising a non-fluorinated polymer.
Type:
Grant
Filed:
December 1, 1980
Date of Patent:
September 13, 1983
Assignee:
Massachusetts Institute of Technology
Inventors:
Madhu Anand, Raymond F. Baddour, Robert E. Cohen
Abstract: The activity of a microbiologically active material is measured by suspending the material in a liquid medium capable of forming a gel. The resultant suspension is formed into small liquid droplets which droplets are caused to gel. The gel microdroplets (GMDs) are treated to effect desirable alteration of the microbiologically active material and the amount of metabolites or reaction products of the desired alteration within each get droplet is measured. Alternatively, incubation is carried out such that each GMD initially containing one cell contains many, a microcolony, which can be tested for desirable properties while retaining sufficient viable cells for with growth and harvesting for further testing and/or production.
Abstract: An apparatus and process useful in direct fluorination of a variety of compositions, as well as the fluorinated compositions themselves, are disclosed.The apparatus comprises a cryogenic zone reactor, such as a packed column reactor, suitably divided into a plurality of independently controllable cryogenic temperature zones. Means are also provided to introduce a reactant to be fluorinated as well as to introduce a mixture of fluorine gas and an inert gas.New fluorinated compounds are also disclosed. These include: perfluoro-2-methoxyethyl ether; perfluoro-1,4-dioxane; perfluoro-2,5-diketohexane; perfluorohexamethylethane; and monohydropentadecafluoroadamantane.Additionally, new syntheses for trifluoroacetic acid, a commercially significant bulk chemical, are disclosed. One synthesis comprises producing perfluorooethyl acetate by direct fluorination using a cryogenic zone reactor, followed by hydrolysis of perfluoroethyl acetate. Two moles of the acid are produced for each mole of ester.
Type:
Grant
Filed:
July 17, 1981
Date of Patent:
August 23, 1983
Assignee:
Massachusetts Institute of Technology
Inventors:
Richard J. Lagow, James L. Adcock, Norma J. Maraschin
Abstract: A method of coating a portion of the walls and effecting a degree of penetration into a bone with a coating material to produce a modified bone surface, the method comprising: introducing the coating material onto the bone surface in an initial physical state; applying pressure to the coating material to force the material into the structure of the bone; and maintaining pressure on the coating material until it reaches a desired final physical state.
Type:
Grant
Filed:
April 27, 1981
Date of Patent:
August 23, 1983
Assignee:
Massachusetts Institute of Technology
Inventors:
George W. Pratt, Jr., Robert Poss, Timothy T. Lane
Abstract: Molecules or cells of materials exhibiting a microbiological activity, suppression or interaction of interest are isolated from a large population of similar molecules, cells or the like. The activity of the microbiologically active molecules or living matter of interest is measured by suspending the population in a liquid medium capable of forming a gel. The resultant suspension is formed into droplets which are caused to gel. The gel droplets (GMDs) are treated to effect desirable alteration of the microbiologically active material and the amount of metabolites or reaction products of the desired alteration within each of the gel droplets. Alternatively, incubation is carried out such that each GMD initially containing one cell contains many, a microcolony, which can be tested for desirable properties while retaining sufficient viable cells for further growth and harvesting for further tesing and/or production.
Abstract: The level of glycine in the brain and in the spinal cord is regulated by administering a neutral amino acid composition to a human wherein increased or decreased brain and spinal cord levels of glycine is effected when the composition contains increased or decreased amounts of threonine or a precursor of L-threonine. The neutral amino acid composition can be administered alone or concomitantly with a drug which either has the undesirable side effect of suppressing glycine-mediated neurotransmission or whose therapeutic efficacy is enhanced by increasing glycinergic neurotransmission.
Abstract: A mixing device (e.g., a stirrer) to ensure thorough mixing of metals and metal alloys comprising a generally rectangular solid and a series of off-side, but area-equivalent ports on each side of the axial center, wherein the size and number of ports on one side is different from the size and number of ports on the other side, the upper and lower limits of the ports being defined by oppositely opposed anguarly directed fin portions wherein the fins on one side of the axial center are directed in one direction and the fins on the other side of the axial center are directed in the opposite direction. The invention also embodies a method of mixing molten metals and alloys with the device.
Abstract: Stable, viscous polymers of silicon, nitrogen and hydrogen are formed by reacting a halosilane with ammonia in the presence of a solvent comprising an aliphatic ether, a chloromethane or mixtures thereof. After the solvent has been removed from the reaction product, the polymer can be poured into a container of desired shape and then can be sintered to form a uniform silicon nitride product.
Type:
Grant
Filed:
November 16, 1981
Date of Patent:
August 9, 1983
Assignee:
Massachusetts Institute of Technology
Inventors:
Dietmar Seyferth, Christian C. Prud'Homme, Gary H. Wiseman
Abstract: There is disclosed a heparin product obtained by degradation of heparin with heparinase from Flavobacterium heparinum (ATCC 13125) or mutants thereof having activity to reduce the coagulation activity of factor X while not effecting the coagulation activity of thrombin.
Type:
Grant
Filed:
August 24, 1981
Date of Patent:
August 2, 1983
Assignee:
Massachusetts Institute of Technology
Inventors:
Robert S. Langer, Robert J. Linhardt, Charles L. Cooney, Gerald Fitzgerald, Arthur Grant
Abstract: Maltase is produced by growing a mutant of the yeast strain Saccharomyces italicus capable of growing in a growth medium utilizing sucrose as the carbon source. Maltase production is optimized by controlling time of fermentation, growth medium composition and sonication time during maltase recovery.
Abstract: Cellulosic products having a high hemicellulose to lignin weight ratio are obtained by extracting a cellulosic composition with basic ethanol-water solution having a pH between about 12 and about 14 at a temperature between about 15.degree. and about 70.degree. C. and for a time period between about 2 and about 80 hours.
Abstract: A method of forming a conductive polymer comprising a blend of at least one processable polymer, polyacetylene and a dopant by impregnating the processable polymer with a Ziegler-Natta catalyst; exposing the impregnated polymer to acetylene gas, whereby substantially linear molecules of polyacetylene are formed within a matrix of the processable polymer; and introducing a dopant into the polyacetylene, whereby a conductive blend is formed.
Abstract: A novel method and device for precision injection molding is disclosed providing controlled cooling of a portion of the mold cavity surface during the molding cycle, or several such portions independently, and also, in the preferred embodiment controlled heating of a portion of the mold cavity surface during the molding cycle or several such portions independently, whereby high quality, high precision parts having close dimensional tolerances may be produced. Another aspect of the invention, a volume-controlled variable conductance heat pipe is disclosed, which novel heat pipe comprises housing means forming a sealed chamber, fluid, such as water or ammonia, within the chamber, wicking means and control means for controling the thermal conductance of the heat pipe comprising means for controlling the volume of fluid in the liquid phase in the chamber.
Abstract: An improved metal dual insulator semiconductor capacitor memory is disclosed. The memory contains a plurality of capacitor cells, each cell comprising a semiconductor substrate layer and a high conductivity layer sandwiching two insulator layers. The substrate is doped to provide avalanche breakdown in a surface depletion layer at a voltage comparable to the write voltage in the accumulation direction. The invention also provides a method of reading stored information without disturbing adjacent cells. A small variable voltage is applied across a "flat-band" portion of the hysteresis loop describing the voltage-capacitance relationship for the capacitor memory. A change or the absence of a change in the current through the capacitor indicates the state of the capacitor cell. Methods to fabricate the memory are also disclosed.
Abstract: An optical transistor wherein an optical medium receives a pump signal and produces therefrom an internal optical signal, an optical control signal being directed into the optical medium to perturb the optical properties of the medium and to thereby modify the amplitude of the internal optical signal. A plurality of optical transistors are shown in various logic configurations.
Abstract: Biologically active sulfur analogs of 6-aminopenicillanic acid having a nucleophile substituted in the 6- position are made by reacting a sulfenyl chloride with esters of diazopenicillanic acid. Biologically active sulfur analogs of 7-aminocephalosporanic acid having a nucleophile substituted in the 7- position are analogously made by reacting a sulfenyl chloride with esters of 7-diazocephalosporanic acid. Deacetoxycephalosporins can be formed from the corresponding analog of 6-aminopenicillanic acid and derivations thereof, by sulfoxide rearrangement of the thiazolidine ring of penicillins to the dihydrothiazine ring of cephalosporins. These nucleophile substituted sulfur analogs of penicillins and cephalosporins are new antibacterial agents and display antibacterial activity against a variety of microorganisms.
Abstract: An asynchronous logic array capable of directly implementing Petri net specification of digital systems is disclosed. The array can be used in general synthesis of asynchronous digital circuits and systems. The parallel nature of the array gives the realized systems the speed and other characteristics of hard wired circuits even though they are realized from a uniform logic array. The logic array is particularly suited for implementing control circuits and promises to extend the field of micro programming to asynchronous and parallel computers.