摘要:
Specific genetic deletion are identified in mycobacteria isolates, including variations in the M. tuberculosis genome sequence between isolates, and numerous deletion present in BCG as compared to M. tb. These deletions are used as markers to distinguish between pathogenic and avirulent strains, and as a marker for particular M. tb. isolates. Deletions specific to vaccine strains of BCG are useful in determining whether a positive tuberculin skin test is indicative of actual tuberculosis infection. The deleted sequences may be reintroduced into BCG to improve the efficacy of vaccination. Alternatively, the genetic sequence that corresponds to the deletion(s) are deleted from M. bovis or M. tuberculosis to attenuate the pathogenic bacteria.
摘要:
Specific genetic deletion are identified in mycobacteria isolates, including variations in the M. tuberculosis genome sequence between isolates, and numerous deletion present in BCG as compared to M. tb. These deletions are used as markers to distinguish between pathogenic and avirulent strains, and as a marker for particular M. tb isolates. Deletions specific to vaccine strains of BCG are useful in determining whether a positive tuberculin skin test is indicative of actual tuberculosis infection. The deleted sequences may be re-introduced into BCG to improve the efficacy of vaccination. Alternatively, the genetic sequence that corresponds to the deletion(s) are deleted from M. bovis or M. tubercuosis to attenuate the pathogenic bacteria.
摘要:
A retractable and extendable medical needle protective shield which provides opportunity for accessing and reaccessing a medical needle and associated sharpened needle tip and recovering the needle and tip for safety between accesses. The shield includes a needle guide which assures the needle tip is untouched by any part of the shield as the shield is displaced to cover and uncover the needle. A releasible latch is provided to guard against inadvertent removal of the protective shield between accesses. An unreleasible latch is also provided to secure the shield relative to the latch preparatory to final disposal. In combination with the protective shield, a plurality of adapters are disclosed which provide examples of passively operated, protected access to membrane pierceable fluid sources such as a “Y” connection site of an IV set line, a drug vial, a vacuum sample tube, an umbilical cord holder and a hypodermic site.
摘要:
An invention which provides for making low cost apparatus and one-hand activation methods for shielding a syringe needle as a safety precaution after each needle use. A shield, which may be used as a protective cover for the needle during initial transport to site of use, is linearly actuated to three distinct stops by action of a single hand, thereby leaving the second hand of a user free for patient care. The shield is releasible from two of the three stops to make possible uncovering of the needle preparatory to use and temporary needle protection between needle uses. The shield has an elongated hollow barrel shape which is sized to fit snugly about, yet slide smoothly over a body of a syringe associated with the needle. The barrel shape of the shield is longitudinally interrupted by a scissure in which an arm which is hingeably affixed to the shield resides. The arm is selectively bent to provide operative surfaces which permit the shield to be released from two of the three stops and further displaced to selected stops by inward depression of the arm. The invention utilizes a collet with a slot and a pawl which interacts with at least one set of ratchet teeth on the arm to provide one of the releasible stops. Generally release from stops is actuated by inward pressure on a predetermined portion of the arm.
摘要:
An efficiency enhanced turbine engine and method are disclosed for a turbine engine having a rotor and a fluid flow path that extends through compression, combustion, and expansion or turbine stages with fluid flowing through the fluid flow path driving the rotor. The turbine engine has one or more stator-rotor-stator assemblies, and use of a flat rotor disk with turbine blades provides simplicity in fabrication and operation. Increases in pressure during combustion above the pressure at the compression stage are prevented from flowing back to the compression stage and/or capturing of fluid during combustion enables elevation of the temperature and pressure while maintaining the fluid at near constant volume during combustion, both of which enhance the efficiency of the turbine engine. Fluid flow is preferably in a circumferential direction and the fluid is caused to reenter the rotor a plurality of times to provide cyclic exposure of the moving parts of the turbine engine to different portions of the engine cycle for reducing the average temperature of the moving parts and thereby allow higher compression ratios and combustion temperatures to also yield higher efficiency.
摘要:
There is provided a gas generating composition consisting essentially of a mixture of nitroguanidine, phase stabilized ammonium nitrate and an elastomeric binder. When the ammonium nitrate is phase stabilized with from about 7% to about 20%, by weight, of a potassium salt, the mixture is structurally and volumetrically stable over typical automotive operating temperatures and has a melting temperature in excess of 100.degree. C. The mixture generates large volumes of nitrogen and carbon dioxide when ignited with minimal generation of solids or toxic gases and is particularly useful as an inflating medium for automobile airbags.
摘要:
An air conveyor is provided with a plenum chamber with a perforated deck plate, side walls, and a holddown with holes of an area density sufficiently low to pressurize an enclosed article transport zone. The side walls include brackets for mounting doors openable to remove damaged articles. The deck plate is mounted to support bars by countersunk rivets.
摘要:
A detector for a dynamic phenomenon with a cyclically varying condition, as motion of a rotating part. At least three digital sensors are separated in phase with respect to the cyclic condition. The instantaneous outputs of the sensors have a plurality of repeating sequential states so long as the dynamic phenomenon exists. The instantaneous outputs of the sensors have at least one state which does not occur during existence of the dynamic phenomenon but which does occur in the absence thereof. Logic circuits respond to the digital sensor outputs and detect information about the dynamic phenomenon. Detection of the repetition rate of an instantaneous output state of the sensors provides a measure of speed. An absence of rotation is indicated by the occurrence of another output state. In another disclosed embodiment, the detector monitors a three phase power system and detects a phase outage by the occurrence of an abnormal sensor output state.
摘要:
An air conveyor includes guides for stabilizing articles during conveyance and a plenum with apertures for providing pressurized air. In the preferred embodiment, the air conveyor also includes opposed spacers defining passages having a closed end and an open end. The passages are in fluid communication with the apertures of the plenum for directing streams of pressurized air through the open ends at the articles in a downstream direction to propel the articles. In another embodiment, channels defined in support structure for the guides form part of passageways for directing streams of pressurized air at an inclined and downstream angle to propel the articles. The guides are removable to allow the conveyor to be adapted to different sized and shaped articles. The air conveyor may also include an additional plenum and additional opposed spacers associated with the plenum for propelling the articles downstream. The angle of the slots can be larger for creating an article-to-article separation or smaller for creating a contiguous article flow.
摘要:
A system for regulating an alternating current voltage source has a pair of P-channel MOSFETs and a pair of N-channel MOSFETs in a bridge configuration with an inductor-capacitor tank there between. A processor in conjunction with a feedback circuit regulates the energy transferred to the tank by modulating the pulse width of signals that are output from the processor and which are used as inputs to the gates of the MOSFETs. By increasing or decreasing the pulse widths transmitted to the various gates of the MOSFETs, the processor increases or decreases the energy transferred to the tank. The feedback circuit is connected between the tank and the processor so that the processor can compare the feedback voltage from the tank to a threshold level in the processor and modify the pulse widths at the output of the processor accordingly.