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Biomedical subjects

R Millner

Publications and source records attributed to R Millner.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Ultrasound attenuation as a function of frequency in formalin fixed testicular tissue].

Measurements of the ultrasound attenuation were carried out in 10 normal testes and 20 pathologically changed testicular tissue biopsies in vitro after formalin fixation. The ultrasound attenuation as function of the frequency was recorded ultrasound-spectroscopically about the complete frequency spectrum of the ultrasound-broad range transformer (3-8 MHz). The frequency dependence of the attenuation behaviour differed in the 10 normal testes from the 20 pathologically changed biopsies by smaller values of the ultrasound attenuation coefficient a (linear regression analysis). The ultrasound attenuation in a characteristic measuring point allows the differentiation between normal and pathologically changed testicular tissue. The following comparison with the histologic evidences showed the correspondence of the results.

Adolescent↗
PubMed1987

Effects of ultrasound on the catalytic activity of matrix-bound glucoamylase.

The effect of ultrasonic waves on the activity of glucoamylase bound to a porous polystyrene matrix is investigated in this Paper. The immobilized enzyme was sonated in a flow cuvette at frequencies between 1 and 11 MHz and sound intensities up to 5 kW m-2. The effect was measured as a function of the type and concentration of the substrate, carrier particle size, flow rate of the substrate solution and ultrasonic frequency. The activity increase is discussed in terms of a possible ultrasonic mechanism.

Catalysis↗
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↗
PubMed1982

[Ultrasonic spectroscopic examinations of pathologically altered testes].

The sonographic differentation of solidly growing and displacing processes is discussed so far only with a high factor of insecurity. The ultrasonic spectroscopy makes it possible for an approximate differentation of the tissue in the experimental investigations in vitro by the reception of bioacoustic parameters. Certainly some questions are open in case of the different forms of neoplasia of the testes. The spreading of the impulse sound field in the tissue cannot be described exactly up to today, because of the indistinct acoustic qualities of the structure in the macroscopic and microscopic region. The clearing of the biophysical reciprocity between sound field and tissue stands in the foreground of the future investigations. The ultrasonic spectroscopy performs despite of the open problems a constructive share to the findings in pathological processes of the testes.

Humans↗
PubMed1980

[Objective determination of prostate size with ultrasound].

The rectal digital examination of the prostate is, despite the high diagnostic value, for a large part subjective in its evidence. By means of the ultrasound examination the size of the prostate may be objectified, which otherwise is difficult to be described, and thus may be used as a firm and reproducible relation size in the diagnosis and control of the course of disease of the prostate which are accompanied by an increase of the organ.

Adult↗