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Biomedical subjects

J Tapson

Publications and source records attributed to J Tapson.

7 recordsLinked to original sources
PubMed2001

High power resonant tracking amplifier using admittance locking.

A high power resonance tracking ultrasonic amplifier is described. The amplifier is a class D type inverter, configured as a half-bridge in which the output MOSFETs are driven into saturation when on. The resonance tracking system makes use of a new method of frequency locking; admittance locking is used to track the optimum power conversion frequency for the transducer. This new arrangement offers some advantages over phase locking and motional feedback methods. The system is capable of delivering up to 3 kW at up to 25 kHz in resonance tracking operation.

Humans↗
PubMed2000

A novel phase locked cavity resonator for B/A measurements in fluids

A new technique for the measurement in fluids of the acoustic non-linearity parameter B/A is presented, together with measured B/A values for several fluids. The non-linearity parameter is measured by phase locking radial modes within a PZT cylinder. The system, which implements the isentropic phase technique, uses continuous wave phase locking to measure the change in sound velocity that is typically associated with a change in ambient pressure under constant entropy. The method provides a means of measuring B/A in vitro both accurately and simply without the typical problems involved in time-of-flight systems. Fluid samples can remain small due to the nature of the cavity resonator, so the system is well suited to small volume, biological samples.

Journal Article↗
PubMed1994

Listening to local voices: adapting rapid appraisal to assess health and social needs in general practice.

OBJECTIVES: To explore the use of rapid appraisal in defining the health and social needs of a community and to formulate joint action plans between the residents and service providers. DESIGN: Collection of data by an extended primary care team from three sources: existing documents about the neighbourhood, interviews with a range of informants, and direct observations to build a profile of the community. SETTING: Council estate of 670 homes in Edinburgh. MAIN OUTCOME MEASURES: Perceived problems of the community and suggestions for change. RESULTS: The interviews and focus groups identified six priorities for change, many of which were not health related. These changes have been or are being implemented. CONCLUSIONS: An expanded primary care team can use rapid appraisal as a first step in identifying and meeting local health needs. It facilitates a multidisciplinary approach and complements quantitative methods of assessing need.

Community Participation↗
PubMed1992

Immunoperoxidase techniques and histology in the diagnosis of rhabdomyolysis related acute renal failure.

A case of rhabdomyolysis associated acute renal failure (RM-ARF) occurring as a result of strenuous exercise is presented. Diagnostic renal biopsy was performed. The histological appearances, combined with immunoperoxidase staining for myoglobin, allowed a positive diagnosis of RM-ARF to be made and excluded the possibility of glomerulonephritis. The patient recovered completely after a stormy clinical course.

Acute Kidney Injury↗