Wave breaking on the surface of a dielectric liquid in a horizontal electric field

The weakly nonlinear dynamics of the free surface of a dielectric liquid in an electric field directed tangentially to the unperturbed boundary is investigated numerically. Within the framework of the strong field model, when the effects of capillarity and gravity are not taken into account, it is shown that nonlinear surface waves have a tendency to break. In result of the collapse of the surface waves, the curvature of the boundary and the gradient of the local electric field undergo infinite discontinuity on the surface of the liquid. The angles of the boundary inclination remain small. The characteristic collapse time of a surface wave traveling in a given direction is calculated versus the dielectric constant of the liquid. It is shown that the time of the singularity formation increases infinitely at small and high values of the dielectric constant. The first case corresponds to the transition of the system to the neutral stability regime (the jump in electrostatic pressure at the boundary turns into zero). At high values of the dielectric constant of the liquid, the collapse time also increases. This effect is associated with the realization of a special regime of fluid motion, in which the propagation of nonlinear surface waves of an arbitrary configuration occurs without distortions. For the liquids with relative permittivity close to five, the wave breaking time reaches a minimum, i.e., the collapse of the surface waves for such liquids occurs most intensively.Comment: 7 pages, 5 figure

Application of technologies of atomic force microscope investigation for evaluation of structure and properties of blood cells’ surfaces

With application of techniques of atomic force microscope investigation, we studied properties and topography of blood cells’ surfaces in patients with acute lymphoblastic and myeloblastic leucosis. It was stated that development of acute forms of lymphoblastic and myeloblastic types of proliferation is accompanied with reduction of stiffness of cell surface and increase of surface potentia

Test-system for estimation of activity of GSK-3 inhibitors as antihypoxants and differentiation of endothelial progenitors in vitro

A model test-system was developed for validation in vitro of antihypoxic and endothelio-differentiating activity of newly created glycogen synthase kinase-3 inhibitors in comparison with the reference drug β4-thymosi

Dynamics of the Free Surface of a Conducting Liquid in a Near-Critical Electric Field

Near-critical behavior of the free surface of an ideally conducting liquid in an external electric field is considered. Based on an analysis of three-wave processes using the method of integral estimations, sufficient criteria for hard instability of a planar surface are formulated. It is shown that the higher-order nonlinearities do not saturate the instability, for which reason the growth of disturbances has an explosive character.Comment: 19 page

Comparative performance of selected variability detection techniques in photometric time series

Photometric measurements are prone to systematic errors presenting a challenge to low-amplitude variability detection. In search for a general-purpose variability detection technique able to recover a broad range of variability types including currently unknown ones, we test 18 statistical characteristics quantifying scatter and/or correlation between brightness measurements. We compare their performance in identifying variable objects in seven time series data sets obtained with telescopes ranging in size from a telephoto lens to 1m-class and probing variability on time-scales from minutes to decades. The test data sets together include lightcurves of 127539 objects, among them 1251 variable stars of various types and represent a range of observing conditions often found in ground-based variability surveys. The real data are complemented by simulations. We propose a combination of two indices that together recover a broad range of variability types from photometric data characterized by a wide variety of sampling patterns, photometric accuracies, and percentages of outlier measurements. The first index is the interquartile range (IQR) of magnitude measurements, sensitive to variability irrespective of a time-scale and resistant to outliers. It can be complemented by the ratio of the lightcurve variance to the mean square successive difference, 1/h, which is efficient in detecting variability on time-scales longer than the typical time interval between observations. Variable objects have larger 1/h and/or IQR values than non-variable objects of similar brightness. Another approach to variability detection is to combine many variability indices using principal component analysis. We present 124 previously unknown variable stars found in the test data.Comment: 29 pages, 8 figures, 7 tables; accepted to MNRAS; for additional plots, see http://scan.sai.msu.ru/~kirx/var_idx_paper

Eclipsing variable stars in the Moscow program for scanning the astronomical plate stacks

Рассматриваются результаты полуавтоматического поиска затменных переменных звезд по сканам московской коллекции астронегативов и особенности распределения обнаруженных затменных переменных по периодам.We consider the results of our semi-automated search for eclipsing variables using scans of the Moscow astronomical plate stacks and characteristics of the eclipsing variables’ distribution over periods

Современные представления о клинических, морфологических и молекулярно-биологических предикторах чувствительности рака молочной железы к химиотерапии

In the treatment of breast cancer, the neoadjuvant chemotherapy is vitally important and the evaluation of its effectiveness is crucial for determining the further therapy treatment, as well as the prognosis of the disease. This review provides current data of the physical, instrumental, morphological, molecular biology and genetics analysis used for the estimation of the neoadjuvant treatment effectiveness. Thus, review discusses the data concerning association of the disease peculiarities with the efficient therapeutic response to neoadjuvant chemotherapy including characteristics of patients (age, status of regional lymph nodes, presence of the lymphovascular invasion) and tumors (size, histological type, degree of differentiation, severity of the lymphoid tumor infiltration, molecular biological and genetic peculiarities). Particular attention is paid to such a promising predictive marker of the breast cancer response to chemotherapy as the level of tissue hypoxia. This section discusses the currently known mechanisms that might enable the effect of tissue hypoxia on the sensitivity of the tumor to drug treatment. The prospects for the use of a comprehensive analysis of predictive markers of the effectiveness of chemotherapeutic treatment are discussed.В лечении рака молочной железы особое место занимает неоадъювантная химиотерапия, оценка эффективности которой имеет ключевое значение для коррекции проводимой терапии, а также для определения прогноза заболевания. В настоящем обзоре приведены современные данные о физикальных, инструментальных и морфологических методах исследования, используемых для оценки эффективности неоадъювантного лечения. Мы рассмотрели данные об ассоциации различных характеристик развития опухолевого процесса с ответом на неоадъювантную химиотерапию, среди них характеристики пациенток (возраст, статус регионарных лимфатических узлов, лимфоваскулярная инвазия, молекулярно-генетические особенности) и опухоли (размер, гистологический тип, степень дифференцировки, выраженность лимфоидной инфильтрации, молекулярно-биологические и молекулярно-генетические особенности). Один из разделов статьи посвящен такому перспективному предиктивному маркеру ответа опухоли на проводимое лечение, как уровень тканевой гипоксии. В данном разделе рассмотрены известные в настоящее время механизмы, которые обеспечивают влияние тканевой гипоксии на чувствительность опухоли к лекарственному лечению. Обсуждены перспективы применения комплексного анализа предиктивных маркеров эффективности химиотерапевтического лечения