Abstract: A one piece integrally formed sectional shaped liner for use in combination with similarly shaped sectional liners in a generally cylindrical chamber of a centrifuge rotor. The utilization of a plurality of similarly shaped plastic liners within a single rotor chamber allows for the placement of different fluid samples in a single rotor during one centrifuge run. The liners are designed in such a manner that they do not require a separate capping means and are preferably made through a blow molding process. The liners are designed to provide adjacent support to each other during the centrifugation run.

Abstract: For use in a system for analyzing sample constituents by metastable transfer emission spectroscopy, an improved apparatus for mixing a sample gas with a metastable gas. The apparatus provides an unobstructed path for the flow of sample gas so as to minimize deposition of the sample on walls of the apparatus. The apparatus may comprise an annular manifold coaxially mounted around a conduit through which flows the sample, or it may comprise a collar detachably connected in line with such a conduit.

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 filter assembly for collecting particulate matter from a stream of sample gas. A filter housing having at least an inlet section and an outlet section supports one or more removable filter elements between adjacent housing sections. At least one end of each housing section is provided with a tapered flange whereby it may be joined to the end of an adjacent housing section. Quick-release clamping means engages the flanges to provide a convenient means for fastening and unfastening the sections of the filter housing without dislodging appreciable quantities of the particulate matter collected on the filter elements. The filter assembly may be expanded as required to accommodate any desired number of filter stages.

Abstract: A method and apparatus is disclosed for selectively determining by non-dispersive infrared techniques the concentration of a gaseous constituent in a sample gas mixture while determining and discounting deleterious effects of spectrally interfering gases in the sample gas mixture.

Abstract: An improved bichromatic or polychromatic spectrophotometer comprising means enabling the user to electronically select which wavelength of a preselected pair of wavelengths shall serve as a "sample" wavelength, with the other then serving as a "reference" wavelength.

Abstract: An improved apparatus for facilitating the practice of a method for determining the conversion efficiency of the NOx converter of an oxides of nitrogen analyzer. An improved ozone control assembly facilitates the control of the ozone content of the gas mixture that is applied to the input of the analyzer. An improved gas flow regulating arrangement allows the composition of the gas mixture to be changed without affecting the flow rate thereof. Together, these structures improve the stability and ease of use of the conversion efficiency detector.

Abstract: A gas analyzer is disclosed which provides a dual channel capability for the simultaneous determination of the presence and concentration of two gases in a stream of sample gas and which has a single infrared source, a single sample cell, two infrared bandpass filters, and two infrared detectors.A separator between the filters and detectors prevents interchange of radiation between the filters. The separator is positioned by fitting it in a slot.

Abstract: An improved hydrazine analyzer is disclosed wherein sample and electrolyte solutions are supplied from constant flow rate sources into a mixing chamber where they are premixed. The premixed combination of electrolyte and sample is then passed through a sensing chamber having a sensing thimble disposed therein. The thimble is of a porous material having a platinum wire electrode wound about the outside thereof and having a silver wire inserted into silver chloride salt on the inside thereof to form a reference half cell. As the electrolyte-sample mixture passes through the sensing chamber, a portion of the fluid passes from the outside of the thimble to the inside of the thimble wetting the silver chloride salt to establish electrical contact and provide the internal filling solution of the reference half cell.

Abstract: An ink priming system for a multi-pen recorder of the gravity-fed capillary tube type comprises a gas manifold common to all of the ink bottles individually provided for each channel of the recorder. Individual control valves may be selectively actuated by the operator to prime each pen. When the control valve is closed, the gas pressure is bled off so that the inking system thereafter acts as a normal gravity-fed capillary tube system. A non-clogging inking system is provided by utilizing a short length of flexible thin walled tubing to supply ink to the movable recording pen. The length of this tubing is sufficiently short that evaporation of the ink solvent through the walls of the tube is accompanied by diffusion of the dye back to the ink bottle so that the concentration of dye in the ink at the end of the tube adjacent the recording pen does not exceed saturation value during prolonged periods of non-use of the recorder.

Abstract: In a spectrophotometer including a photomultiplier tube responsive to light for producing an analog current proportional to the intensity thereof, an analog-to-digital converter, a signal path from the photomultiplier tube to the analog-to-digital converter, the analog-to-digital converter producing a digital signal as a function of the analog current, and computer means responsive to the digital signal for generating a signal for compensating for the dark current of the photomultiplier tube, there is disclosed a method and means for reducing the dark current correction error by temporarily increasing the gain of the signal path during calculation of the value of the compensating signal.

Abstract: An automatic transfer method and apparatus for a multi-variable control unit having at least two process control units is disclosed which initiates transfer from the selected controller to the non-selected controller through failure of the selected controller to produce transfer preventing signals.

Abstract: In a sulfur dioxide analyzer which measures the content of sulfur dioxide by fluorescence of sulfur dioxide molecules when illuminated by an ultraviolet light source, there is disclosed a converter containing vanadium pentoxide for removal of polynuclear aromatic hydrocarbons which produce interference when sulfur dioxide is measured by fluorescent methodology.

Abstract: In a sulfur dioxide fluorescence analyzer, a method and apparatus for eliminating the fluorescence effects of nitric oxide is disclosed wherein a sample gas is mixed with a diluent which substantially quenches nitric oxide fluorescence.

Abstract: A keyboard type switch is disclosed wherein a domed snap disc performs triatic functions of acting as a tactile feedback source for switch operation, of supplying a conductive path for electrical energy when depressed, and of providing a contact surface for manual operation. The disclosed switch is covered by a multilayered nonconductive membrane and spacer to provide maximum safety from electrical shock to the operator.

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 and apparatus for removing moisture from a sample stream of gas while preventing dilution of the concentration of components of successive increments of the sample stream of gas.

Abstract: Titration apparatus for measuring chloride electrolyte in blood samples including a pair of coulometric generating electrodes (anode and cathode) for titrating the chloride with silver ions to precipitate silver chloride and a pair of amperometric detecting electrodes for detecting uncombined silver ions following complete titration of the chloride and hence for signaling the endpoint of the chloride titration. A predetermined potential difference is applied across the amperometric electrodes, and an operating condition of zero current flow is established through one of the amperometric electrodes. Current flow between the amperometric electrode and the coulometric anode is monitored to indicate the presence of uncombined silver ions and thereby the titration endpoint.

Abstract: A system for continuous monitoring for open circuits in multiple lead EEG systems during patient testing. Means are provided for repetitively applying a low current signal, having a distinctive waveform and frequency, to each electrode of the system. In the event an electrode is detached from the patient's scalp or otherwise open, the distinctive signal is apparent in the recorded output. Otherwise the distinctive signal is of such low magnitude that it is below the signal-to-noise ratio of the EEG amplifier. In systems including multiple leads, the test signal is successively applied to each electrode in the system in a time-controlled sequence. In one preferred embodiment a distinctive signal is used comprising a four pulse burst of 25 Hz frequency.