Abstract: Improved filter assemblies are provided having a pleated filter medium attached to a support frame utilizing an improved manufacturing method employing a welding process to seal the pleated edges of the filter medium to an inwardly protruding sealing means provided on the frame around the inside perimeter thereof, forming a final filter assembly exhibiting an essentially leak-proof edge seal.

Abstract: A positive pressure demand valve for breathing apparatus incorporates a tubular "balanced piston" valve member for regulating the flow of breathing gas from an inlet to an outlet. A coaxial tension spring acts to bias the valve member open and a lever coupled to a pressure-responsive diaphragm acts to push the valve member closed when a predetermined pressure is attained within the outlet. A combined pressure-relief and bypass valve member enables the operation of the main valve member to be bypassed by porting gas through the center of the main valve seat. A "first breath" mechanism is provided comprising a hooked link which can be pressed in by a button to maintain the main valve member closed and can be released by contact by the diaphragm when a negative pressure is applied to the outlet. The outlet is in the form of a bayonet connector which is locked into a corresponding inlet fitting on the user's mask by means of the same button.

Abstract: A self contained breathing apparatus comprises a compressed air cylinder, facemask and hose which when not in use are stored and carried within a case formed from an assembly of flexible sheet material. The elements of the case are constructed such that when it is opened and reversed it is adapted to form a garment to be worn over the torso and support the air cylinder for use.

Abstract: In a data communication system a plurality of users are equipped with respective devices for computation and authentication of message authenticators. Each device stores a common cryptographic function; a common secret key and a respective non-secret offset for the key. They are programmed to perform the functions of: (i) computing and outputting an authenticator for an entered message using the cryptographic function and key combined with the respective offset; and (ii) computing an authenticator for an entered message using the cryptographic function and key combined with any entered offset, comparing that authenticator with one received with the message and displaying a "pass" or "fail" decision. The devices are incapable of displaying or otherwise outputting any authenticator computed using any offset other than its respective stored offset, however. In this way it can be ensured that a transmitted authenticator can act as a verifiable "signature" to a message uniquely identifying the sender.

Abstract: A data communications system, e.g. for "hands free" personnel location or access control, comprises a master transceiver and a plurality of slave transceivers for transmitting individual identification messages to the master in accordance with a code in which binary values are represented by an infra-red transmission occuring during a first portion or a second portion of a bit period respectively. The master alternately echoes back to the slaves a binary value corresponding to the value last received. In the event of a clash, however, i.e. different values transmitted from different slaves during the same bit period, the master echoes back only a predetermined single value and the slave(s) which did not transmit that value then cease transmission. This process continues until one of the slaves has transmitted and had echoed back bit-by-bit the whole of its message.

Abstract: A plurality of portable tokens are issued e.g. for authenticating instructions within an electronic banking network. Each token requires entry of a respective password in order to operate and becomes locked if a number of incorrect password entries are made. Each token also stores a respective cryptographic key and a random number generator. In order to unlock a locked token it outputs a random number and also encrypts that number under its respective key but does not output the result of the encryption. The random number is transmitted by the user to a central authority which stores the keys for all tokens. The authority encrypts that number under the respective key and returns the result of the encryption to the user of the token. The returned number is entered into the token and if it agrees with the result of the internal encryption the token is unlocked.

Abstract: This invention relates to certain conjugates of folates and antifolates with difluoroglutamic acid which are useful in the treatment of patients suffering from certain neoplastic diseases including leukemia, melanomas, carcinomas, sarcomas and mixed neoplasias.

Abstract: An improved foamable protein hydrolysate based concentrate is provided containing multivalent cations and a water soluble polymer, which remains stable in storage for at least six months and which, when diluted with 10 to 50 parts of water and mixed with air to generate a foam, produces a foam which lasts essentially unchanged for at least three days.

Abstract: AFFF and ARAFFF firefighting foam concentrates which include alkyl polyglycoside surfactants are provided. These surfactants enhance the performance of the perfluoroalkyl surfactants.

Abstract: An electronic lock is constructed to resemble the appearance and functionality of a conventional cylinder lock. Its key has a bit in which is mounted an integrated circuit chip storing the key code and including a transmission coil for inductive coupling with a reading head in the lock. The latter includes a coil for generating a high frequency alternating magnetic field across a localized region of the keyway concentrated via a toroidal ferrite core structure which defines a gap spanning the keyway through which the chip passes when the key bit is inserted. This core structure includes a U-shaped part in the stationary lock housing around which the coil is wound, and two parts mounted in the barrel, one to either side of the keyway, which register with the part in the housing when the barrel is in the key-reading position. Further ferrite pads may be mounted to either side of the coil in the key itself, to register with the ferrite parts in the barrel.

Abstract: A method and apparatus for covering substrates such as landfills, sewage, contaminated soil, sludge deposits, compost piles and the like. A protein based solution, preferably mixed from a foam concentrate, is mixed with air in a foam production nozzle and then spread to an approximately uniform thickness over the surface of the substrate.In an alternative embodiment the present invention also relates to a method for providing a foam covering to substrates such as buildings and other natural and artificial structures to protect such substrates from adverse environmental conditions such as polluted air or water, insects, extreme hot and cold temperatures and toxic vapors or substances.

Abstract: The present invention provides a method for manufacturing light weight abrasive tumbling media made up of discrete abrasive particles desirably exhibiting an essentially uniform size and shape which comprises adding at least 15%, and preferably 20% by weight of a naturally occurring or synthetically produced metal carbonate to a ceramic/clay based formable mixture prior to firing to obtain particles having a final fired bulk density below 65 lbs/ft.sup.3. Such a carbonate may desirably be selected from the group consisting of calcium carbonate, lithium carbonate, magnesium carbonate, zinc carbonate or compounds containing a predominant amount of one or more of these carbonates.

Abstract: New compounds are described of the formula: ##STR1## wherein Z is selected from ##STR2## each x is selected from ##STR3## n is an integer from 1-10; each Y is selected from hydrogen, --NH.sub.2, --COQ, --COOQ, --COONHQ, --COOH, --OH, W, halogen and Q; wherein each Q is independently selected from substituted and unsubstituted lower alkenyl and lower alkyl and wherein the substitutuents are selected from --NH.sub.2 halogen, --OH, and --COOH; D is selected from hydroxy, hydrogen and --NH.sub.2 ; and W is selected from ##STR4## wherein each R is independently selected from hydrogen and lower alkyl; R' is selected from ethylene, propylene, isopropylene and phenylene; M is selected from chlorine and hydroxy; A is selected from hydrogen, lower alkyl, lower alkenyl, cycloalkyl, and phenyl; (B) is selected from ##STR5## --CO--, --NHCO--, --O--, --COO--, --N.dbd.N--, or represents a confugate bond; L.sub.1 and L.sub.

Abstract: This invention relates to an improvement to a process for synthesizing cellulose aminomethanate wherein cellulose is steeped in an aqueous urea containing solution, dried to form an intimate mixture of cellulose and urea of known composition, and heated to form the cellulose aminomethanate; the improvement comprising, heating the mixture to a temperature above about 125 degrees centigrade, measuring the weight loss of the mixture during heating, comparing the measured weight loss of the mixture during heating to the weight of an equivalent amount of ammonia released in accord with the reaction path:Cell-OH+CO(NH.sub.2).sub.2 .fwdarw.Cell-OCONH.sub.2 +NH.sub.3continuing heating until the total measured weight loss corresponds to the total weight of an amount of ammonia released in the reaction when from about 30 to about 100% of the total weight of urea present in the mixture reacts with cellulose.

Abstract: Novel arabinopyranosyl nucleoside derivatives having the heterocyclic moiety and fluorine at the 2' position of the sugar ring (pyranose configuration), which have antitumor, antiviral and antimicrobial properties, are prepared by condensation of a pyrimidine, purine or 1,3-oxazine base with an acylated 2-deoxy-2,2-difluoro-D-arabinopyranoside and/or acylated 2-deoxy-2-bromo-2-fluoro-D-arabinopyranoside.