Theory and Applications of X-ray Standing Waves in Real Crystals

Theoretical aspects of x-ray standing wave method for investigation of the real structure of crystals are considered in this review paper. Starting from the general approach of the secondary radiation yield from deformed crystals this theory is applied to different concreat cases. Various models of deformed crystals like: bicrystal model, multilayer model, crystals with extended deformation field are considered in detailes. Peculiarities of x-ray standing wave behavior in different scattering geometries (Bragg, Laue) are analysed in detailes. New possibilities to solve the phase problem with x-ray standing wave method are discussed in the review. General theoretical approaches are illustrated with a big number of experimental results.Comment: 101 pages, 43 figures, 3 table

Механизмы регуляции сократительной активности гладкомышечных клеток: роль активных форм кислорода

The effect of modulation of hydrogen peroxide, nitric oxide and hydrogen sulfide on contractile reactions of smooth muscle cells caused by depolarization, phenylephrine and solutions with altered osmolarity has been investigated by the mechanographical method. The new data of the fundamental nature of the role of reactive oxygen species in the operation of calcium and cGMP-mediated intracellular signaling systems, as well as in volume-dependent regulation of smooth muscle contraction.Методом механографии изучено влияние модуляции перекиси водорода, оксида азота и сероводорода на сократительные реакции гладкомышечных клеток, вызванные гиперкалиевой деполяризацией мембраны, фенилэфрином и растворами с измененной осмолярностью. Получены новые данные фундаментального характера о роли активных форм кислорода в оперировании кальциевой и цГМФ-опосредованной внутриклеточных сигнальных систем, а также в объемзависимой регуляции сокращений гладких мышц

TXRF spectrometry in the bioanalytical sciences: A brief review

This work describes the basic principles of Total-reflection X-Ray Fluorescence (TXRF) spectrometry and some of its most outstanding applications for investigating metal traces, mainly in biological and biomedical samples. TXRF is an analytical technique that combines the versatility of elemental analysis by X-ray energy dispersion with a low detection limit in the order of picograms of absolute mass or a few ppb (μg L−1) as concentration. The microanalytical capacity of TXRF allows the study of small sample quantities. The TXRF can perform qualitative and mass ratio analyses of the elements present in a sample of only a few hundred nanograms. These properties are of great importance in the research of metal traces in biological systems, as they allow fast, precise, and accurate characterisation of the elemental fingerprint at trace level. Its successful application in studies of the coordination kinetics of new platinum-based antitumor drugs with DNA, its application in the study profile of the metal in healthy and cancerous human tissues, or even its application in the study of the processes of metal diffusion through cell membranes are just a few examples of TXRF capabilities in the biomedical sciences. This brief review's main objective is to provide an overview of the physical principles and possibilities of TXRF spectrometry. It also highlights some of the most outstanding applications that have been developed so far, mainly in the biological field, so that the reader can evaluate their potential applicationsThis article is into the frame of the COST Action CA18130 ENFORCE TXRF, supported by COST (European Cooperation in Science and Technology

The regulation mechanisms of contractile activity of smooth muscle cells: reactive oxygen species role

The effect of modulation of hydrogen peroxide, nitric oxide and hydrogen sulfide on contractile reactions of smooth muscle cells caused by depolarization, phenylephrine and solutions with altered osmolarity has been investigated by the mechanographical method. The new data of the fundamental nature of the role of reactive oxygen species in the operation of calcium and cGMP-mediated intracellular signaling systems, as well as in volume-dependent regulation of smooth muscle contraction