Search

Start Over Creator Jan Hálek Harvested from CDK Harvested from CDK Data provider Academy of Sciences Library/Knihovna Akademie věd ČR

3. Derivation of sonograph quality parameters by the use of point spread function analysis

Creator:
Ladislav Doležal, Jiří Mazura, Tesařík, J., Hana Kolářová, David Korpas, Binder, S., and Jan Hálek
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, ultrasonografie, jakost, ultrasonography, quality, point spread function, imaging, 14, and 612
Language:
English
Description:
A measuring system evaluating a Point Spread Function generated in an ultrasonographic image by scanning a spherical target was developed. The target is moved in measuring bath filled by water over scanned volume via 3D computer controlled positioning system. A video signal obtained is converted to digital form and analyzed by original software to derive various objective parameters of the imager as follows: Focal areas in both the azimuth and the elevation directions, Ultrasound scanning lines visualisation, Manufacturer preloaded TGC, Width of the scanning plane, Side lobe levels and Amplification uniformity in the azimuth direction. The method was verified by testing 18 different equipments in 282 measurements. Samples of particular measurement results in form of graphical outputs are included. Medical and physiological impacts of this approach are discussed., L. Doležal, J. Mazura, J. Tesařík, H. Kolářová, D. Korpas, S. Binder, J. Hálek., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. In vitro study of reactive oxygen species production during photodynamic therapy in ultrasound-pretreated cancer cells

Creator:
Hana Kolářová, Bajgar, R., Kateřina Tománková, Krestýn, E., Doležal, L., and Jan Hálek
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, photodynamic therapy, sonodynamic therapy, phthalocyanine sensitizer, reactive oxygen species, 14, and 612
Language:
English
Description:
Several recent studies bring evidence of cell death enhancement in photodynamic compound loaded cells by ultrasonic treatment. There are a number of hypotheses suggesting the mechanism of the harmful ultrasonic effect. One of them considers a process in the activation of photosensitizers by ultrasonic energy. Because the basis of the photodynamic damaging effect on cells consists in the production of reactive oxygen species (ROS), we focused our study on whether the ultrasound can increase ROS production within cancer cells. Particularly, we studied ROS formation in ultrasound pretreated breast adenocarcinoma cells during photodynamic therapy in the presence of chloroaluminum phthalocyanine disulfonate (ClAlPcS2). Production of ROS was investigated by the molecular probe CM-H2DCFDA. Our results show that ClAlPcS2 induces higher ROS production in the ultrasound pretreated cell lines at a concentration of 100 μM and light intensity of 2 mW/cm2. We also observed a dependence of ROS production on photosensitizer concentration and light dose. These results demonstrate that the photodynamic effect on breast cancer cells can be enhanced by ultrasound pretreatment., H. Kolářová, R. Bajgar, K. Tománková, E. Krestýn, L. Doležal, J. Hálek., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Otokar Chlup: (1875-1965)

Creator:
Jan Hálek
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Věda. Všeobecnosti. Základy vědy a kultury. Vědecká práce, Chlup, Otokar, 1875-1965, věda a společnost, pedagogika, pedagogové, science and society, educationalists, educational science, 12, and 00
Language:
Czech
Description:
Letos uplyne 140 let od narození a 50 let od smrti tohoto pedagoga, prvního děkana Pedagogické fakulty Univerzity Karlovy v Praze, prvního ředitele Pedagogického ústavu J. A. Komenského ČSAV a nositele mnoha vyznamenání. and Jan Hálek.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

7. Parameters describing the pulse wave

Creator:
David Korpas, Jan Hálek, and Ladislav Doležal
Type:
article, články, model:article, and TEXT
Subject:
Lékařské vědy. Lékařství, lékařská biofyzika, tepny, měření, pulz (lékařství), medical biophysics, arteries, measurement, pulse, plethysmography, pulse wave, arterial elasticity, 14, and 61
Language:
English
Description:
Pulse wave analysis permits non-invasive assessment of arterial elasticity indices. The contour varies in different parts of the circulation. It depends on physiological or pathophysiological conditions of the organism. The pathological events like arteriosclerosis or diabetes have a primary effect to the artery elasticity. Hypertension or some heart diseases al so influence the pulse wave velocity and resulted in earlier wave reflections. There are several methods of pulse wave measurements based on different principles and depending on the type of measured pulse wave. The evaluation parameters can be assessed from the time domain, derivations, velocity or frequency domain. The main aim of this review article is to offer a recent overview of pulse wave measurement parameters and main results obtained. The principles of pulse wave measurement and current experience in clinical practice are shortly discussed too., D. Korpas, J. Hálek, L. Doležal., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public