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Biomedical subjects

F Holzer

Publications and source records attributed to F Holzer.

12 recordsLinked to original sources
PubMed1982

[Experimental studies of signal fields of ultrasound broad band transducers].

Quantitative analysis of ultrasonic signals, as increasingly practised, makes it necessary to increase the band width as well as the efficiency of ultrasonic transducers. An broad band ultrasonic transducer is presented which meets the requirements by double lambda/4 layer matching and was specially designed for medical ultrasonic spectroscopy. In an extended measurement programme transmitter characteristic, spatial dependence of the spectral content of the transmitter signals as well as beam geometry and its frequency dependence are investigated and compared with conventional transducers.

Fourier Analysis↗
PubMed1980

[Optimizing the fibrinogen-thrombin adhesive system].

It was the aim of the present three series of investigations to determine conditions to improve the firmness of the clot produced by the fibrinogen-thrombin adhesive system. For methodological reasons the compressive strength and adhesive power of the clot, as well as the probability of a relation between deformation energy and tensile strength were examined. Furthermore, the influence of fibrinolysis on the effects of the adhesive system was investigated. The following factors proved to be relevant for the firmness of the clot: 1. Concentration of fibrinogen, 2. concentration of thrombin, 3. relation between volume of fibrinogen and of thrombin solution, 4. time of diffusion of constituents of mixture, 5. addition of blood-clotting factor XIII and solution of calcium ions. The following optimum concentrations of components of the adhesive system per ml of the mixture were established in the course of the investigations: Fibrinogen solution (approx. 10% clottable material) 0.86 ml Thrombin 100 E. Factor XIII 90 E. = 30 mg Ca++ 250 mMol A volume ratio of 6 parts of fibrinogen as cryoprecipitate to 1 part of a solution containing thrombin, factor XIII and calcium ions proved optimal for the preparation of the mixture.

Animals↗
PubMed1976

Effects of xipamide and triamterene - alone or in combination - on electrolyte excretion in the rat.

The effects of X and T in different doses alone or in combination on renal sodium and potassium excretion were examined in conscious rats. In acute experiments, the combination of both diuretics produced an approximately additive effect on sodium excretion. Addition of T to X in different dose relations (X:T = 1:0.5, 1:1 or 1:1.5) prevented the X-induced potassium loss. These effects were more pronounced at the highest dose of T; the difference to the other combinations, however, was small. In chronic experiments, when the diuretics were administered daily for 13 days, both combinations (X:T = 1:1 and X:T = 1:1.5) resulted in a nearly equilibrated potassium balance at the end of this period. In shorter intervals, however, sometimes considerable oscillations in potassium excretion occured.

Animals↗
PubMed1975

Error calculation in the study of renal metabolism.

1) By the aid of error calculation various formula structures of method in the renal metabolism have been investigated in regards to their intermediary information contents. 2) The effects of the formations of the means and the error calculation on correlation and significance test are shown. 3) The calculation was carried out for a mean relative error of the means which were 1 respectively 5% of the determinants. It showed how dangerous it can be to calculate with means without taking into account the errors induced.

Analysis of Variance↗