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Biomedical subjects

G L Zick

Publications and source records attributed to G L Zick.

4 recordsLinked to original sources
PubMed1993

A network model for wide area access to structural information.

Structural information in medicine is information about the physical body. Recent advances in medical imaging and biotechnology have greatly increased the amount and importance of structural information, and advances in networking envisioned by the High Performance Computing and Communication Initiative (HPCC) will allow this kind of information to be delivered to remote clients over wide area networks. One of the most important factors determining the usability of such a client-server configuration is the time delay between the request for information from the server, and its presentation to the user at the client. In this paper we present a model for predicting the performance of a structural information client based on the ping time, a simple, unobtrusive network measurement. Preliminary results suggest that the relationship between ping time and transfer time for large files is linear, which if borne out by more data, will allow the performance of structural information clients at remote sites to be predicted without the expense of installing them first. At the same time, such a model will be useful for planning improvements to the network in those sites which could most benefit by wide area access to structural information.

Computer Communication Networks↗
PubMed1981

Laser Doppler velocimetry vs heater power as indicators of skin perfusion during transcutaneous O2 monitoring.

Laser Doppler velocimetry (LDV) and heater power (HP) were compared as indicators of skin perfusion during transcutaneous oxygen tension (ptcO2) monitoring in adults. The LDV probe was fitted to a Radiometer ptcO2 attachment ring, which was fixed to the forearm. ptcO2, electrode temperature, HP, and LDV measurements were recorded continuously and simultaneously. LDV was more specific and sensitive to changes in cutaneous perfusion. Moreover, changes in perfusion were signalled four to 24 times faster by LDV than by HP. Changes in ptcO2 corresponded to changes in LDV more closely than to changes in HP in all experiments. HP was more specific and sensitive to changes in electrode and air temperatures. Once hyperemia was established at 44 degrees C and the electrode heater was turned off (HP = 0), LDV measurements frequently showed persistence of hyperemia (up to 25 min). Under these circumstances ptcO2 decreased linearly with decreasing electrode temperature in the range of 44-32 degrees C. LDV performance was referenced by monitoring velocity measurements taken on a cylinder revolving at known velocities. We conclude that LDV is a useful adjunct to ptcO2 monitoring and better than HP in assessing skin blood flow. It should enhance quality control of transcutaneous O2 monitoring.

Adult↗
PubMed1977

Design of the pulsed oxygen cathode.

This paper presents a theoretical design of the pulsed oxygen cathode. The analysis concerns two major areas: First, a description of the oxygen diffusion currents during the initial 5 msec. after the application of the polarization potential. Second, a determination of the limiting sample rate imposed by a protective coating of given characteristics. It is shown that at 5 msec. after application of the polarization potential the 99% isoconcentration line is 11.8 micron from the cathode surface. The currents during this time can be modeled as linear diffusion. Also, for a minimum step response of 100 msec. the protective coating should have a thickness less than or equal to 13.6 micron.

Cold Temperature↗