Abstract: A method and apparatus for determining an insufficient liquid volume. The invention includes an electromagnetic sensing device in a conduit into which the sample liquid is mixed. The electromagnetic sensing device detects the presence of air in the conduit which indicates that an insufficient liquid volume has been aspirated.

Abstract: A safety latching apparatus for a cover of a machine enclosing a round rotatable member. The apparatus includes a latch member, and an elongated flexible control element for sensing the motion of the rotatable member to automatically prevent opening of the cover when the member is rotating. The control element is movable longitudinally so that one of its ends can be brought into contact with the rotatable member and the other end connected to a latching mechanism located adjacent the machine cover. When the rotatable member is stationary, the end of the control element brought into contact with it remains generally rigid to a force in the longitudinal direction allowing the latch member to move to an unlocked position.

Abstract: A multi-channel instrumentation system is provided wherein signals from selected electrode pairs are sequentially connected to the isolated input of a common signal amplifying path. The electrode pair selecting means is included in a portable head box which may be placed adjacent to the patient to be tested. Included in the head box are facilities for testing the impedance of any selected one of the patient electrodes and providing a visual indication of the magnitude of such impedance. The head box also includes facilities for selecting a group of patient electrodes which are connected together and used as an average or reference potential for one input of the common signal path. Facilities are also provided for calibrating the common signal path by applying a d.c. calibration signal to the input thereof by means isolated from system ground.

Abstract: A method of quench correction in liquid scintillation counting which compensates for the effect of sample quench. A quench corrected pulse height window is established for measuring sample scintillations. A pulse height threshold is established distinguishing regions for which a measure of sample quench, derived conventionally, is either proportional to or not proportional to the actual effect of quench on the sample pulse height spectrum. The quench corrected window is compared with the pulse height threshold, and the relative position of the corrected window is adjusted if the comparison step indicates that the window lies in the region of nonproportionality.

Abstract: A method and related apparatus for the determination of a random coincidence count attributable to chance coincidences of single-photon events which are each detected in only a single detector of a scintillation counter utilizing two detectors in a coincidence counting technique. Real and apparent coincidences of pulses are accumulated in a first counting device (28), and all pulses from the detectors (12) are accumulated in a second counting device (38), without regard for coincidence in time. The two counting devices are monitored during at least one random coincidence monitoring time occurring simultaneously with part of a sample counting period. The length and frequency of occurrence of the random coincidence monitoring times can be selected for particular counting measurement applications.

Abstract: An electrode termination assembly for use on a display device wherein the amount of space required for the pin connector to attach to the display device is greatly reduced, the physical and electrical integrity of the assembly is greatly enhanced and the cost of the assembly is reduced as compared to present assemblies for pin connectors. An adhesive material having conductive particles is used to not only physically support and attach the connector pins to the display, but also electrically connect the connector pins to electrode pads on the display.

Abstract: A cover having a free-turning knob in its center for use on the rotor of a centrifuge. The knob includes tool means for coupling the knob with a threaded fastener securing the rotor to a drive shaft. Thus, when the cover is positioned on the rotor, the threaded fastener securing the rotor can be tightened or loosened by a turning of the knob. The rotor can thereby be removed and replaced without the use of external tools.

Abstract: A communication system for communicating digitally encoded information from a remote transmitting station to a central receiving station. The central station supplies d-c operating power to a remote station through a d-c power distribution line. A voltage regulator at the remote station receives the d-c operating power and derives therefrom a constant d-c voltage for powering the circuitry of the remote station. A digital transmitter at the remote station changes the magnitude of the current drawn through the voltage regulator, in accordance with a message to be transmitted, and thereby changes the current in the power distribution line without affecting the voltage supplied to the circuitry of the remote station. These line current changes are detected and decoded at the central station to reconstruct the transmitted message.

Abstract: Novel peptides having the following amino acid sequence ##STR1## wherein X.sub.1, X.sub.2, and X.sub.3 are selected from a group consisting of N-terminal and desamino alpha-carbon substitutions and a and b are 0 or 1, provided that a and b are always 0 when A.sub.1 is a desamino residue; A.sub.1 and A.sub.4 are selected from a group consisting of histidyl, arginyl, lysyl, .alpha.-naphthylalanyl, .beta.-naphthylalanyl, isoquinolyl, tyrosyl, tryptophyl, phenylalanyl, homologues and analogues thereof, and, with respect to A.sub.1 only the desamino forms thereof; A.sub.2 and A.sub.5 are selected from a group consisting of D-histidyl, D-arginyl, D-lysyl, D-.alpha.-naphthylalanyl, D-.beta.-naphthylalanyl, D-isoquinolyl, D-tyrosyl, D-tryptophyl, D-phenylalanyl, homologues and analogues thereof; A.sub.

Abstract: A switching voltage regulator is provided for coupling a source of AC potential to a DC load. Thyristor full wave rectifier means provide a source of DC potential which is connected to the load through an inductance in series with the load. The input of the inductance is shunted by a commutating diode which provides a path for the inductive current when the thyristor means are in the nonconducting phase of their operating cycle. Circuit means are provided to reverse bias the commutating diode in advance of each conduction cycle of the thyristor means. As a consequence, the level of RFI conducted to the AC power line is significantly reduced.

Abstract: An ion activity or concentration analyzer including an ion selective electrode, a reference electrode and a flow-through electrolytic cell. A sample liquid enclosure conducts a flow of an aqueous sample past the anode and cathode electrodes of an electrolytic cell that is polarized to generate hydrogen and hydroxyl ions. The ion selective and reference electrodes are so positioned, with respect to the cathode electrode, that the hydroxyl ion concentration is increased in the vicinity thereof. This increased hydroxyl ion concentration causes a reduction in the hydrogen ion concentration and thereby substantially eliminates the interfering effect of hydrogen ions on the operation of the ion selective and reference electrodes.

Abstract: Novel combinations comprising (a) at least one peptide having the following amino acid sequence ##STR1## wherein X.sub.1, X.sub.2, and X.sub.3 are selected from a group consisting of N-terminal and desamino alpha-carbon substitutions and a and b are 0 or 1, provided that a and b are always 0 when A.sub.1 is a desamino residue; A.sub.1 and A.sub.4 are selected from a group consisting of histidyl, arginyl, lysyl, .alpha.-naphthylalanyl, .beta.-naphthylalanyl, isoquinolyl, tyrosyl, tryptophyl, phenylalanyl, homologues and anlogues thereof, and, with respect to A.sub.1 only the desamino forms thereof; A.sub.2 and A.sub.5 are selected from a group consisting of D-histidyl, D-arginyl, D-lysyl, D-.alpha.-naphthylalanyl, D-.beta.-naphthylalanyl, D-isoquinolyl, D-tyrosyl, D-tryptophyl, D-phenyalanyl, homologues and analogues thereof; A.sub.

Abstract: An improved electrode assembly for use in amperometric gas sensors. A portion of the interior of the electrode assembly that is adjacent to the electrode is filled with an electrochemically inert water-repellant fluid. Once the fluid is in place, a fluid barrier is inserted to cover the fluid and to serve as a foundation for the introduction of a sealing compound. A pressure relief structure, such as a gas bubble, may be provided within the fluid to relieve the pressures incident to the thermal expansion and contraction of the electrode assembly. Because of the water repellancy of the fluid, the electrolyte solution which surrounds the electrode assembly is prevented from migrating into the interior thereof and thereby initiating output current errors.

Abstract: A multi-channel instrumentation system is provided wherein signals from selected electrode pairs are sequentially connected to the isolated input of a common signal amplifying path. The electrode pair selecting means is included in a portable head box which may be placed adjacent to the patient to be tested. Included in the head box are facilities for testing the impedance of any selected one of the patient electrodes and providing a visual indication of the magnitude of such impedance. The head box also includes facilities for selecting a group of patient electrodes which are connected together and used as an average or reference potential for one input of the common signal path. Facilities are also provided for calibrating the common signal path by applying a d.c. calibration signal to the input thereof by means isolated from system ground.

Abstract: Pentapeptides which act directly on the pituitary to release growth hormone therefrom.

Abstract: A stepper motor positioning control utilizing phase detection of the stepper motor windings. The device utilizes crude positioning apparatus to position the attached turntable or the like in an approximate position. The phase detection of the stepper motor windings is then used to position the attached turntable in the exact location desired.

Abstract: A method of constructing a gas discharge display device in such a manner that contaminants found within the completed display are significantly reduced. The process for assembly of the display incorporates the utilization of a spacer member having a higher melting temperature than the display's perimeter seal and is designed to hold the plates apart without letting certain portions of the sealing material contact the opposing substrate. The use of the spacer member of high temperature material permits a higher temperature to be achieved in the vacuum furnace for evacuating the contaminants produced by out-gassing of impurities in the dielectric and conductive materials as well as the glass substrates and the sealing material. The sealing time for the display after evacuation is shortened to prevent or greatly reduce the possible entrapment of impurities in the display during the higher temperature final sealing step.

Abstract: A swinging bucket centrifuge rotor having a plurality of cavities spaced about its vertical axis and extending entirely through the rotor. Each cavity is adapted to receive a bucket supported by a hanger rod. The mounting of the bucket is such that the bucket can pivot or swing from a vertical to a horizontal position during operation. Each cavity is provided with a slot, which extends along the underside of the rotor, from the cavity to the periphery of the rotor. The slot has an upper surface adapted to receive the bucket when the bucket is in the horizontal position. A pair of opposed grooves extend partway down the wall of the cavity whereby the ends of the grooves each form a ledge to support an end of the hanger rod by which the bucket is pivotally suspended.

Abstract: An automated pipette employing a device to ensure exact volume pickup and delivery. An optical device senses the presence of a liquid in the tip of the pipette. By intaking the volume past the optical device stream continuity is determined.

Abstract: A retractible stop mechanism is disclosed, for a conveyor system or the like, in which a stop member is moved up and down between a retracted position and a position in which it blocks an article, and a pivoted tension link is connected between the supporting structure and the stop member to provide the reaction force against the force exerted by the blocked article on the stop member, thereby removing frictional resistance to retraction of the stop member. Also, the location of the pivot of the tension link is such that a force component is developed which assists the retracting force acting on the stop member.