Biomedical subjects

N A Friedman

Publications and source records attributed to N A Friedman.

4 recordsLinked to original sources

PubMed1998

Capillary tube resistive thermal cycling.

A system that performs rapid thermal cycling of microliter and smaller liquid volumes inside glass capillary tubes that have an optically transparent thin film of indium-tin oxide (ITO) covering the exterior is described. The ITO film acts as both a heater and a temperature sensor, while cooling is accelerated with forced air. Unlike existing batch-mode thermal cycling systems, this system allows control over each sample's temperature profile. Temperature transition rates of 44 degrees Celsius per second during heating and 15 degrees Celsius per second during cooling have been achieved, allowing successful polymerase chain reaction (PCR) experiments to be performed in 20 min. Capillary external temperature can be regulated typically to within +/- 0.25 degrees Celsius, and peak temperatures more than 800 degrees Celsius have been demonstrated. Capillary internal (sample) temperatures at present are controllable typically to within 2 degrees Celsius. The resistive film can be used as a temperature sensor, and the optical transparency of the thin-film coating could permit fluorescent monitoring of the sample during thermal cycling, making this method well suited for real-time quantitative PCRs.

Microchemistry↗

PubMed1998

Flexible software architecture for user-interface and machine control in laboratory automation.

We describe a modular, layered software architecture for automated laboratory instruments. The design consists of a sophisticated user interface, a machine controller and multiple individual hardware subsystems, each interacting through a client-server architecture built entirely on top of open Internet standards. In our implementation, the user-interface components are built as Java applets that are downloaded from a server integrated into the machine controller. The user-interface client can thereby provide laboratory personnel with a familiar environment for experiment design through a standard World Wide Web browser. Data management and security are seamlessly integrated at the machine-controller layer using QNX, a real-time operating system. This layer also controls hardware subsystems through a second client-server interface. This architecture has proven flexible and relatively easy to implement and allows users to operate laboratory automation instruments remotely through an Internet connection. The software architecture was implemented and demonstrated on the Acapella, an automated fluid-sample-processing system that is under development at the University of Washington.

Automation↗

PubMed1989

Periarthrosis of the shoulder associated with diabetes mellitus.

Among the protean complications of diabetes mellitus are contractures of the joints and periarticular soft tissue. These complications have not been well described in the literature. This syndrome of "limited joint mobility," has been reported as occurring in young, insulin-dependent diabetics, with primary involvement of the small joints of the hands. In older diabetics, similar changes have been described with additional contractures developing in the large joints of the upper extremities. This report presents clinical findings occurring in five older diabetics with primary contractures of the shoulder. Theoretical considerations are also discussed regarding the neurophysiology of this entity as well as the current treatment options.

Adult↗

PubMed1986

"Tethered" median nerve stress test in chronic carpal tunnel syndrome.

Tension of the median nerve produced by simultaneous extension of the supinated wrist and distal interphalangeal joint of the index finger was noted to result in proximal volar forearm pain radiation in patients with chronic carpal tunnel syndrome. This sign was less frequent in patients with a more acute syndrome. Adhesions between the median nerve and the overlying transverse carpal ligament and the development of a pseudoneuroma can individually or together occur in the chronic carpal tunnel syndrome limiting distal nerve excursion of the tethered nerve during simultaneous wrist and index finger extension.

Carpal Tunnel Syndrome↗