Abstract: An improved ramp generating circuit which is self-compensating for changes in component performance is disclosed. The circuit is designed to attain a reference voltage in a fixed number of counts as provided by a precision clock source. A single direction compensation feedback network is employed to increase the slope in increments until the desired peak level and clock count are attained simultaneously. Embodiments are shown wherein the circuit is employed in a gas discharge bar graph display driving circuit and as an analog-to-digital converter.

Abstract: A method of flameless atomic absorption analysis in which an element in a sample is measured by vaporizing the sample in a graphite crucible or cuvette and measuring the absorbance of the atomic vapor at a wavelength characteristic of the element. The method includes the steps of (1) successively introducing a preselected number of aliquots of the same sample into the graphite cuvette, (2) thermally pretreating each sample aliquot upon introduction to remove volatile or decomposable substances therefrom, and (3) vaporizing sample remaining in the cuvette for measurement only after performing the predetermined successive number of sample introduction and thermal pretreatment cycles.

Abstract: In a system for analyzing the elemental or molecular composition of a sample wherein the sample components are excited through collision with an active metastable gaseous species, the excited sample components emitting a characteristic wavelength of light which may be detected, the system including a microwave cavity through which the gaseous species flows and a microwave source coupled to the cavity, the microwave discharge exciting the gaseous species, there is disclosed an improved liquid sample introduction system which causes complete vaporization and disassociation of the sample. The sample is preferably aspirated directly into the microwave discharge within which the active gas is generated. A novel sample and gas injection probe is also disclosed.

Abstract: Pipetting and diluting apparatus including an interchangeable syringe pump of predetermined volume capacity and a stepper motor for driving the syringe piston at a selected speed for dosing a selected volume of fluid. The piston stroke is calculated from the syringe volume capacity and the volume of fluid to be dosed. Control means controls the acceleration and deceleration characteristic of the piston in accordance with an exponential function dependent upon the selected piston speed and the syringe volume capacity.

Abstract: Novel pentapeptides having the following amino acid sequenceX-Y-Z-E-G-J-Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y and E are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; Z and G are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; J is selected from a group consisting of glycine, alanine, valine, leucine, isoleucine, proline, hydroxyproline, serine, threonine, cysteine, methionine, aspartic acid, glutamic acid, asparagine, glutamine, arginine, and lysine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: Novel tetrapeptides having the following amino acid sequenceX--Y--Z--E--G--Jwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y and G are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; Z and E are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; and J is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: Novel pentapeptides having the following amino acid sequenceX--Y--Z--E--G--J--Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; wherein Y and G are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; Z is selected from a group consisting of glycine, alanine, valine, leucine, isoleucine, proline, hydroxyproline, serine, threonine, cysteine, and methionine; E and J are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: Novel pentapeptides having the following amino acid sequenceX--Y--Z--E--G--J--Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y is selected from a group consisting of D-lysine and D-arginine; Z and J are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; E and G are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: An improved electroencephalograph system is disclosed having a system for automatically verifying the input and output parameters of the various channels, the preset number selected, and a patient identification number. A coded output is used employing the standard EEG pen recorder outputs. Numerical sequences such as the preset number and a patient identification number are displayed on a single event marker channel as modified Roman numeral sequence of digits directly readable by the operator.

Abstract: An enzymatic reagent is provided for use in the kinetic measurement of the concentration of an enzyme substrate present in a sample and possessing the Michaelis-Menten relationship between reaction rate and substrate concentration. The reagent includes an enzyme such as glucose oxidase, uricase or urease for reacting with corresponding enzyme substrates such as glucose, uric acid or urea. In addition, the reagent includes a nonreacting competitive inhibitor of the enzyme. The inhibitor is present in an amount sufficient to improve the linearity of the reaction rate-concentration relationship associated with the enzyme substrate reaction at concentrations which are low relative to the Michaelis-Menten constant, Km, for the particular enzyme substrate reaction. The improved linearity, in turn, improves the accuracy of the kinetic measurements of substrate concentration made by linear output analyzers especially in an upper portion of the predetermined range where the relationship is particularly nonlinear.

Abstract: Apparatus for conveying a blood sample through a flow cell which measures characteristics such as pH, PCO.sub.2, and PO.sub.2 of the sample and for pumping a wash solution through the cell between samples. The flow cell inlet is selectively connected (1) to a sample-filled syringe for driving sample through the flow cell or (2) to a reservoir of the wash solution. The flow cell outlet is connected by a conduit to a waste receptacle. A rotor of a combined peristaltic pump and valve coacts with an elastomeric tubular section of the conduit. The rotor and the elastomeric section are movable in a transverse direction relative to each other between (1) a first or pumping position wherein the rotor compressively engages the section for pumping fluid wash solution through the cell and the conduit and (2) a second or relaxed position wherein the rotor is released from the section to provide an open unrestricted channel for the flow of sample driven by the syringe through the cell.

Abstract: A short path liquid junction structure is defined through a porous ceramic layer coated circumferentially on an electrochemical electrode glass body by an elastomeric O-ring sealing member circumferentially engaging the ceramic layer in an annular line contact seal. The length of the liquid junction path is the short distance through the porous ceramic layer around and past the line contact seal.

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: A sample holder and shutter assembly for photometers is disclosed in which a stationary sample chamber body is mounted in close proximity to a photosensitive device. A light path is provided from the sample chamber to the photosensitive device and shutter means is provided for selectively interrupting and opening the light path between the photosensitive device and the sample chamber without moving the sample chamber. Heat exchange means including a heat pump and a heat reservoir are provided for maintaining a desired temperature in the sample chamber. The sample chamber body is thermally connected to said heat pump and is preferably thermally isolated from the means mounting it. In one embodiment, the heat pump and heat reservoir are flexibly connected.

Abstract: An improved rotor imbalance detector for a centrifuge comprising a rotatable electrically conducting ring; means to support and insulate the conducting ring from the centrifuge spindle shaft, and yet permit rotational movement of the conducting ring with respect to the support means, when the conducting ring is struck by the centrifuge drive spindle during an imbalance condition, means for de-energizing the power supplied to the centrifuge motor which rotates the drive spindle, and an electrically conducting lead in electrical contact with the conducting ring and the de-energizing means.

Abstract: A synthetic pentapeptide of opiate agonist activity having the formula H-Tyr-Gly-Gly-Phe-Met-NH.sub.2 formed in a solid-state method.

Abstract: A reagent, of the type comprising a precipitator capable of precipitating low density lipoproteins, very low density lipoproteins, and other non-high density lipoproteins, is improved by the addition thereto of a non-interfering suitable agent capable of enhancing the flocculation of a precipitant formed by the precipitator and the various non-high density lipoprotein fractions in highly lipemic serum.

Abstract: There is disclosed a circuit for generating an error voltage which is proportional to the difference between a desired value of a physical parameter and the actual value of the physical parameter. The circuit operates by alternately switching the current from a source through a fixed reference resistor and a variable resistor, the resistance value of which changes as a function of the physical parameter to be controlled. The current is switched between the two resistors so that the average voltage generated across the variable resistor would be equal to the average voltage generated across the fixed resistor if the physical parameter had the desired value. By determining the difference between the average voltages across the resistors, the error voltage can be generated for controlling the physical parameter.

Abstract: Fluorescent displays are comprised of a means for cooperatively aligning a liquid crystal material and a fluorescent medium disposed therein. The fluorescent medium is comprised of a nematic liquid crystal host which is effectively transparent to radiation of both near ultraviolet and visible wavelengths and a fluorescent guest whose visible fluorescent intensity varies with the phase or orientation of the liquid crystal host.