Abstract: A thermal cycler for automatic performance of the polymerase chain reaction is provided. The thermal cycler comprises a heater control that provides close temperature control of the reaction.

Abstract: A thermal cycler for automatic performance of the polymerase chain reaction is provided. The thermal cycler comprises a heater control that provides close temperature control of the reaction.

Abstract: A thermal cycler for automatic performance of the polymerase chain reaction is provided. The thermal cycler comprises a heater control that provides close temperature control of the reaction.

Abstract: A thermal cycler for automatic performance of the polymerase chain reaction is provided. The thermal cycler comprises a heater control that provides close temperature control of the reaction.

Abstract: A thermal cycler for automatic performance of the polymerase chain reaction is provided. The thermal cycler comprises a heater control that provides close temperature control of the reaction.

Abstract: An instrument for performing highly accurate PCR employing a sample block in microtiter tray format. The sample block has local balance and local symmetry. A three zone film heater controlled by a computer and ramp cooling solenoid valves also controlled by the computer for gating coolant flow through the block controls the block temperature. Constant bias cooling is used for small changes. Sample temperature is calculated instead of measured. A platen deforms plastic caps to apply a minimum acceptable threshold force for seating the tubes and thermally isolates them. A cover isolates the block. The control software includes diagnostics. An install program tests and characterizes the instrument. A new user interface is used. Disposable, multipiece plastic microtiter trays to give individual freedom to sample tubes are taught.

Abstract: A thermal cycler for automatic performance of the polymerase chain reaction is provided. The thermal cycler comprises a heater control that provides close temperature control of the reaction.

Abstract: A thermal cycler for automatic performance of the polymerase chain reaction is provided. The thermal cycler comprises a heater control that provides close temperature control of the reaction.

Abstract: A sample tube including a cylindrical part and a conical part is described. The cylindrical part can include, a first wall portion having a first wall portion thickness, a second wall portion having a second wall portion thickness, and a shoulder including a planar first surface and a conically beveled second surface disposed between the first wall portion and the second wall portion. The first wall portion can be disposed closer to the planar first surface than the conically beveled second surface. The conical part can be shaped as a frustrum of a cone having a conical part wall thickness. The frustrum can include a wider-end and a narrower-end. The wider-end of the frustrum can be in contact with the second wall portion of the cylindrical part. At least one of the first wall portion thickness and the second wall portion thickness can be greater than the conical part wall thickness.

Abstract: An instrument for performing highly accurate PCR employing a sample block in microtiter tray format. The sample block has local balance and local symmetry. A three zone film heater controlled by a computer and ramp cooling solenoid valves also controlled by the computer for gating coolant flow through the block controls the block temperature. Constant bias cooling is used for small changes. Sample temperature is calculated instead of measured. A platen deforms plastic caps to apply a minimum acceptable threshold force for seating the tubes and thermally isolates them. A cover isolates the block. The control software includes diagnostics. An install program tests and characterizes the instrument. A new user interface is used. Disposable, multipiece plastic microtiter trays to give individual freedom to sample tubes are taught.

Abstract: An instrument for performing highly accurate PCR employing a sample block in microtiter tray format. The sample block has local balance and local symmetry. A three zone film heater controlled by a computer and ramp cooling solenoid valves also controlled by the computer for gating coolant flow through the block controls the block temperature. Constant bias cooling is used for small changes. Sample temperature is calculated instead of measured. A platen deforms plastic caps to apply a minimum acceptable threshold force for seating the tubes and thermally isolates them. A cover isolates the block. The control software includes diagnostics. An install program tests and characterizes the instrument. A new user interface is used. Disposable, multipiece plastic microtiter trays to give individual freedom to sample tubes are taught.

Abstract: The invention is directed to a differential analysis method and apparatus wherein a sample and reference are subjected to an externally applied disturbance, such as temperature change, in accord with a prescribed function comprising the sum of a linearly changing part and a periodically changing part, and the measured differential signal is processed into real and imaginary components relating, respectively, to the energy storage and energy loss portions of the signal.

Abstract: A two-piece plastic holder for loosely holding microliter sample tubes of a preselected design, each tube having a cylindrically shaped upper section open at its top end, a closed, tapered lower section extending downwardly therefrom, and a circumferential shoulder extending outwardly from the upper section at a position on the upper section spaced from the open end thereof. The holder includes a one-piece tray member and a one-piece retainer. The one-piece tray member including a flat, horizontal plate section containing holes in a rectangular array, a first vertical tray sidewall section around the plate extending upwardly to a height greater than the height of a tube resting in one of the holes, and a second vertical tray sidewall section around the plate extending downwardly approximately to the bottom of the upper section of a tube resting in one of the holes. The one-piece retainer is releasably engageable inside the tray over any sample tubes resting in the tray.

Abstract: An apparatus for controlling level of cryogenic liquid in a vessel includes a transfer duct to a pressure supply tank. Pressure pulses are applied to the tank at one rate when the level is below a primary sensor in the vessel, and at a lower rate when the level is above the sensor, so as to compensate for intrinsic declination of the level. At startup a constant pressure is applied to the tank until the level reaches a lower sensor, and a relief valve over the tank is opened when the level overshoots to an upper sensor. Turbulence in the vessel is reduced by a pair of coaxial baffles at the liquid inlet to the vessel, and by a housing with tubular extensions enveloping the sensors.

Abstract: An instrument for performing highly accurate PCR employing a sample block in microtiter tray format. The sample block has local balance and local symmetry. A three zone film heater controlled by a computer and ramp cooling solenoid valves also controlled by the computer for gating coolant flow through the block controls the block temperature. Constant bias cooling is used for small changes. Sample temperature is calculated instead of measured. A platen deforms plastic caps to apply a minimum acceptable threshold force for seating the tubes and thermally isolates them. A cover isolates the block. The control software includes diagnostics. An install program tests and characterizes the instrument. A new user interface is used. Disposable, multipiece plastic microtiter trays to give individual freedom to sample tubes are taught.

Abstract: The invention is directed to a differential analysis method and apparatus wherein a sample and reference are subjected to an externally applied disturbance, such as temperature change, in accord with a prescribed function comprising the sum of a linearly changing part and a periodically changing part, and the measured differential signal is processed into real and imaginary components relating, respectively, to the energy storage and energy loss portions of the signal.

Abstract: A mass filter for charged particles includes a cylindrical conductive housing at ground potential and an array of linear conductors arranged in parallel in the housing and divided equally into four subarrays. The conductors of each subarray lie in one of four planes having a tubular arrangement with a square cross section on the longitudinal axis of the housing. The conductors have a substantially uniform distribution in the planes. A dedicated voltage is applied to each conductor in each subarray, the voltages being selected cooperatively and with the dimensions of the housing and the square cross section, such that a quadrupole type of electric field is generated within the tubular arrangement. Equations are disclosed for determining the voltages.