Search results for "Activity measurements"
showing 5 items of 5 documents
Die bestimmung von sedimentationskoeffizient, diffusions-koeffizient und molekulargewicht von α-amylasen nach der methode des aktivitätstransportes
1965
Abstract Sedimentation and diffusion coefficients determined by optical methods on pure (crystallized) enzymes are compared with those obtained by activity measurements on the unpurified enzymes. On performing the experiments under suitable conditions, results of the two methods are in good agreement. The calculation of the molecular weights of the unpurified enzymes is somewhat uncertain because the partial specific volume in most cases is not accurately known.
A Ciliary Motility Index for Activity Measurement in Cell Cultures With Respiratory Syncytial Virus
2018
[EN] Background: The respiratory epithelium is frequently infected by the respiratory syncytial virus, resulting in inflammation, a reduction in cilia activity and an increase in the production of mucus. Methods: In this study, an automatic method has been proposed to characterize the ciliary motility from cell cultures by means of a motility index using a dense optical flow algorithm. This method allows us to determine the ciliary beat frequency (CBF) together with a ciliary motility index of the cells in the cultures. The object of this analysis is to automatically distinguish between normal and infected cells in a culture. Results: The method was applied in 2 stages. It was concluded fro…
Study of Proton and 3He Induced Reactions on 235U at Low Energies
2014
Abstract Highly enriched 235 U targets were irradiated with 6.5 − 16.1 MeV protons and 20.4 − 42.0 MeV 3 He ions. The irradiated targets were measured with γ and α spectrometric methods to identify and quantify the produced reaction products. After primary activity measurements the targets were dissolved, and interesting Pu and Np reaction products were chemically separated from the target material, and measured for activity again. From the activity results it was possible to calculate the reaction cross sections for differently produced nuclides. The data obtained from the experiment resulted in earlier unknown excitation functions on proton and 3 He induced nuclear reactions on 235 U.
Accuracy of 210Pb dating in two annually laminated lake sediments with high Cs background
1997
Abstract A low-background gamma ray spectroscopy system has been used for nondestructive determination of 210Pb, 226Ra, 134Cs and 137Cs in lake sediment samples. Two Finnish sediment cores with high 137Cs activity originating from the Chernobyl accident have been analysed and dated using 210Pb. The accuracy of the 210Pb dating method was checked by varve counting of replicate samples. In one lake the 210Pb method gave similar dating results as varves, but in the other lake significant differences were detected. It was found that a high Cs concentration significantly impairs the accuracy of the 210Pb activity measurement. However, tha reliability of the dating result depends mostly on the co…
The effect of ISM absorption on stellar activity measurements and its relevance for exoplanet studies
2017
Past UV and optical observations of stars hosting hot Jupiters have shown that some of these stars present an anomalously low chromospheric activity, significantly below the basal level. For WASP-13, observations have shown that the apparent lack of activity is possibly caused by absorption from the intervening ISM. Inspired by this result, we study the effect of ISM absorption on activity measurements (S and logR'$_{\rm HK}$ indices) for main-sequence late-type stars. To this end, we employ synthetic stellar photospheric spectra combined with varying amounts of chromospheric emission and ISM absorption. We present the effect of ISM absorption on activity measurements by varying several ins…