Abstract: Error multiplication in the differential decoder and descrambler of V.22 bis modems is avoided by replacing the differential coding with forward error correction and single symbol coding. The error syndrome bit of the error corrector is used in establishing phase and timing synchronization by causing the receiver to try all possible combinations of phase and timing, and to lock onto the combination which produces a minimum of error syndrome bits. The descrambler receives the error-free corrected bit stream, whereby the descrambler's inherent error multiplication becomes moot.

Abstract: Accurate in vivo measurement of blood oxygen saturation by fiberoptical means is made possible throughout a wide range of hematocrit or total hemoglobin values by using a single R/IR ratio I and calculating the SO.sub.2 value therefrom through the use of a second-order polynomial of the formSO.sub.2 =Ak.sup.2 I.sup.2 +BkI+Cin which A, B and C are hematocrit or total hemoglobin-dependent coefficients. These values may be contained in a lookup table accessed by a hematocrit or total hemoglobin value selection, and k is a purely multiplicative calibration constant which can be readily determined for any individual fiberoptic system.

Abstract: Previously undesired artifacts in a color signal used in fiberoptic cardiac catheters to measure blood oxygenation levels are used to produce indications of blood flow and true pulse. For this purpose, the color signal is band-pass filtered to derive a DC mean signal level .mu. and an AC signal containing only those frequencies at which the signal is affected by blood flow variations. The RMS value of that band-pass-filtered AC signal (which corresponds to the standard deviation .sigma. of the AC signal) is divided by the DC value .mu. to produce a .sigma./.mu. signal representative of flood flow. By clipping the AC signal and using the resulting square wave to drive a one-shot multivibrator, an indication of the patient's true pulse can be obtained.

Abstract: Stress cracking of polycarbonate parts during prolonged storage while assembled with plasticized polyvinyl tubing is greatly reduced by using tubing in which tri-2-ethylhexyl trimellitate is the predominant or sole primary plasticizer.

Abstract: An opposing vortex oscillator is used to control the frequency and duty cycle of a high-frequency jet ventilator for trauma management in acute and uncontrolled situations where no power other than the pressure of the ventilation gas itself is available. Frequency adjustment is achieved by connecting variable volumes to one inlet of the oscillator while duty cycle control is achieved by supplying fluid to one inlet of the oscillator through a variable-orifice bias control valve. Safety means are provided to automatically disable the ventilator in case of airway blockage.

Abstract: A removable cover for converting a programmable infusion pump into a patient-controlled analgesia (PCA) device. The cover can be placed onto an infusion pump and electrically connected thereto when open. The cover includes an internal switch which allows selection of normal or PCA pump operation. A second internal switch automatically disables the keyboard of the pump when the cover is closed. The cover is lockable, and when it is closed and locked, the internal switches are inaccessible, the cover cannot be removed from the pump, and the electrical connection to the pump cannot be disconnected. When closed, the cover also defines an inaccessible compartment for the storage of medication. An external push button is provided to allow the patient to trigger analgesia doses at safe intervals when the pump is in the PCA mode.

Abstract: Full-flow cardiac assist is provided for cardiogenic shock patients without major surgery by a miniature axial-flow pump which can be inserted into the heart through the femoral artery and driven via a flexible cable from an external power source. The cable is contained within the catheter attached to the pump. The catheter also provides a conduit to supply the pump bearings with a blood-compatible purge fluid at a rate and pressure sufficient to prevent thrombus formation and introduction of blood elements between rotating and stationary elements of the pump. Due to the very small diameter of the pump, rotational speeds on the order of 10,000 to 20,000 rpm can be used to produce a blood flow on the order of about four liters per minute without significant hemolysis.

Abstract: A slit lamp with surgical laser capability includes an x-y table. An optical micrometer, readily retrofittable onto existing slit lamps, is mounted on the x-y table to measure table displacement in the y direction. The measuring electronics are resettable to allow the operator to select any y position from which the displacement is to be algebraically measured. Compact display optics are retrofittably mounted on the ocular assembly of the slit lamp between the collimator and the eyepiece to insert a reduced image of an LED indicator displaying the measured data into the periphery of the ophthalmic image seen through the eyepiece. An LCD indicator displaying the same data is mounted on the x-y table to allow positioning of the table without looking into the eyepiece. The LED indicator lends itself to display of laser operational data in addition to positional data.

Abstract: A disposable strain gauge pressure sensor providing reliable electrical isolation even at defibrillation voltages in the measurement of biological fluid pressures is produced by floatingly mounting a glass plate on a closed cell, fluid-impervious foam pad within a firm but not totally rigid plastic housing. The glass plate has a thin glass diaphragm integrally formed therein which carries the strain gauge element. Openings in the foam pad and the housing allow a fluid contained in a fluid dome on the outside of the housing to bathe the side of the glass diaphragm opposite that on which the strain gauge element is mounted. The glass plate, foam pad, and housing are bonded together in fluid-tight relationship so that fluid cannot reach anything within the housing other than the glass diaphragm. The housing is preferably transparent to allow observation of the diaphragm during operation.

Abstract: A food warmer cover is equipped with an inclined door which forms an effective seal against a pair of shoulders formed in the enclosure of the cover. The door pivots about the tops of the shoulders and slides horizontally into the enclosure to make room for lateral guides inside the enclosure. The guides support the door and also support several warming pans in sliding relationship. The door can be pivoted up and away from the enclosure for cleaning, and it is self-aligning when it is replaced following cleaning.

Abstract: An apparatus for injecting a substance into a human or animal comprising a body adapted to have the substance to be injected pass therethrough, a needle mounted on the body and a needle guard mounted on the body between an extended position in which the guard obstructs access to the point of the needle and a retracted position in which the guard does not materially obstruct access to the point of the needle. The guard is releasably retained in the retracted position, and interlocking members on the body and the guard are responsive to generally axial movement of the guard to the extended position for interlocking to substantially prevent movement of the guard back toward the retracted position.

Abstract: A connector for use in builder's scaffolding systems for connecting crossmembers to upright members where the upright members have sockets provided thereon and each of the sockets has an internal clamping face. The connector is coupled to one end of the crossmember. It has an upper and a lower limb spaced apart for receiving the socket therebetween. A generally trapezoidal opening having four sides, two of which are non-parallel, is provided in the two limbs. In engaging the connector, two of the four sides form first and second clamping sides. A wedge coupling member is received within the trapezoidal opening and mounted for clamping engagement with the internal clamping face of the socket and selected portions of the first and second clamping sides. The trapezoidal opening permits connection of the crossmember at a plurality of angles to the upright within the range permitted by the first and second clamping sides.

Abstract: A device to allow a person to bend forward and place the upper portion of his body above the pelvic region in an inverted position across a padded support placed in a doorway, while stretching his legs out and away from the padded cylinder in a direction generally perpendicular to his inverted body. The feet of the user are restrained through straps secured to a lower portion of the doorway. The user is able to stretch his legs out away from each other, away from his body, either singly or in unison, and can also swing the upper portion of his body above the pelvic region using the padded support as a fulcrum.

Abstract: A simple, versatile switching system for ultrasonic transducer arrays uses in-probe concentration and a crosspoint switching matrix, both under the control of a microprocessor in the control unit. The number of crosspoints is kept to a minimum by connecting transducer elements to the pulse delay or receive delay lines in symmetrical pairs; and the high-voltage pulsing is done on the probe side of the switching matrix to allow the use of the same light-duty matrix for both pulsing and receiving.

Abstract: A float having depending fins and a curved surface on which waves impinge. The float provides an additional lift over and beyond its buoyancy. The float is coupled through a swivel to allow it to turn into the direction of waves. The float is additionally provided with an arrangement to compensate for variations in the mean water level due to tide action.

Abstract: A method and device for phase synchronization for use particularly where a fixed internal clock signal generator is used for both receive and transmit functions.The phase difference between the incoming pulse train and a fixed internal framing clock is detected by a counting circuit which provides an output signal indicating the interval time of the phase difference. A delaying means coupled to the incoming pulse train delays the same in response to the output signal for the time indicated thereby and provide synchronism therebetween.

Abstract: A telephone subscriber testing system is disclosed in which all tests may be performed from a central office. A central office test device is connected to the central office by a separate telephone line with a telephone number of its own. Moreover, a dedicated command channel connects the office test device with a remote test device over the carrier lines. This dedicated channel is used to communicate commands and transmit test results back to the central office. By causing the remote device to "dial up" the office device, the entire trunk loop through the PCM trunk and the central office switching equipment can be tested directly in one measurement at the central office.

Abstract: A wave motion motor is disclosed with an impeller moved by a float. The float is coupled to a swivel arrangement to turn in the direction of wave current and has an inclined underside. Also disclosed are means to adjust to tide level and triangular coupling means between the float and a flywheel.

Abstract: A mass transfer device of the type used, e.g., for blood dialysis is made by winding on a mandrel a series of fiber strands, each of which consists of a solid fiber and one or more hollow fibers, the solid fiber being at least as large, and preferably substantially larger, in diameter than the hollow fiber. As the strands are wound on the mandrel they are temporarily anchored at spaced locations along the mandrel by beads of a liquid pre-potting compound which eventually harden into said anchor plates. When the winding is complete, the mandrel is cut at each anchor plate to form individual temporary cartridges which can withstand the handling required in washing and drying. After each individual cartridge is final-potted, the anchor plates are discarded, and the final potting is cut in a conventional manner to form manifold surfaces at each end of the cartridge.

Abstract: A day-night picture achieves a realistic reproduction of the twinkling of distant city lights or the like, by backlighting small apertures in the picture with a fine, randomly moving reflection pattern obtained by suspending pieces of crumpled reflective foil from fine threads behind the picture above a light source whose heat creates convection currents which slowly move the foil pieces in a random manner.