Contents of heavy metals in fructicose epiphytic lichens of Karelia as indicator of atmospheric transport of pollutants

Results of studies of heavy metals contents in fruticose epiphytic lichens in Karelia are presented and the influence of different sources on the elemental composition of lichens has been estimated. It has been shown, that long-range atmospheric transport influences strongly the accumulation of Pb, Zn, Cd, Sb. For Al, Fe and Co lithogenic source is the main one. In the Northern Karelia atmospheric transport of Cu, Co and Ni from metallurgic enterprises of the Murmansk Region is important source of these elements

Surface Roughness and Effective Stick-Slip Motion

The effect of random surface roughness on hydrodynamics of viscous incompressible liquid is discussed. Roughness-driven contributions to hydrodynamic flows, energy dissipation, and friction force are calculated in a wide range of parameters. When the hydrodynamic decay length (the viscous wave penetration depth) is larger than the size of random surface inhomogeneities, it is possible to replace a random rough surface by effective stick-slip boundary conditions on a flat surface with two constants: the stick-slip length and the renormalization of viscosity near the boundary. The stick-slip length and the renormalization coefficient are expressed explicitly via the correlation function of random surface inhomogeneities. The effective stick-slip length is always negative signifying the effective slow-down of the hydrodynamic flows by the rough surface (stick rather than slip motion). A simple hydrodynamic model is presented as an illustration of these general hydrodynamic results. The effective boundary parameters are analyzed numerically for Gaussian, power-law and exponentially decaying correlators with various indices. The maximum on the frequency dependence of the dissipation allows one to extract the correlation radius (characteristic size) of the surface inhomogeneities directly from, for example, experiments with torsional quartz oscillators.Comment: RevTeX4, 14 pages, 3 figure

Lattice Boltzmann simulations in microfluidics: probing the no-slip boundary condition in hydrophobic, rough, and surface nanobubble laden microchannels

In this contribution we review recent efforts on investigations of the effect of (apparent) boundary slip by utilizing lattice Boltzmann simulations. We demonstrate the applicability of the method to treat fundamental questions in microfluidics by investigating fluid flow in hydrophobic and rough microchannels as well as over surfaces covered by nano- or microscale gas bubbles.Comment: 11 pages, 6 figure

On discretization in time in simulations of particulate flows

We propose a time discretization scheme for a class of ordinary differential equations arising in simulations of fluid/particle flows. The scheme is intended to work robustly in the lubrication regime when the distance between two particles immersed in the fluid or between a particle and the wall tends to zero. The idea consists in introducing a small threshold for the particle-wall distance below which the real trajectory of the particle is replaced by an approximated one where the distance is kept equal to the threshold value. The error of this approximation is estimated both theoretically and by numerical experiments. Our time marching scheme can be easily incorporated into a full simulation method where the velocity of the fluid is obtained by a numerical solution to Stokes or Navier-Stokes equations. We also provide a derivation of the asymptotic expansion for the lubrication force (used in our numerical experiments) acting on a disk immersed in a Newtonian fluid and approaching the wall. The method of this derivation is new and can be easily adapted to other cases

Problems of biomedical ethics in the perception of medical university students

The purpose of the study is to identify students’ awareness of the problems of biomedical ethics.Цель исследования - выявление информированности студентов о проблемах биомедицинской этики

Anisotropic colloids through non-trivial buckling

We present a study on buckling of colloidal particles, including experimental, theoretical and numerical developments. Oil-filled thin shells prepared by emulsion templating show buckling in mixtures of water and ethanol, due to dissolution of the core in the external medium. This leads to conformations with a single depression, either axisymmetric or polygonal depending on the geometrical features of the shells. These conformations could be theoretically and/or numerically reproduced in a model of homogeneous spherical thin shells with bending and stretching elasticity, submitted to an isotropic external pressure.Comment: submitted to EPJ

ПОЖИЛОЙ ВОЗРАСТ, ЗАПОР И ДЕПРЕССИЯ: КАК ЛЕЧИТЬ?

Constipation is one of the key problems of modern therapy for elderly people. The research aim was to study the features of the psychological and microbiological status of the advanced and senile age patients with functional constipation and to see the effect of educational programmes on compliance of the patients with the therapy in the out!patient departments. The investigation showed that depression was more frequent in the patients of group 1 (68.4 % of the cases) with compensated function of the large gut whereas in the 2nd group – 34.6 % (compensated) and in the 3rd group – 41.5 % (subcompensated)cases. The 3rd degree dysbiosis was found in all patoents irrespective of the extern of disorder of the motor!kinetic function in the large gut.Запор является одной из ключевых проблем современной терапии в пожилом возрасте. Целью исследования явилось изучение особенностей психологического и микробиологического статусов у пациентов пожилого и старческого возраста с функциональным запором, а также влияние образовательных программ на приверженность к терапии в амбулаторных условиях. Как показали результаты исследования, чаще всего депрессия встречалась у пациентов 1 группы - в 68,4 % случаев - с компенсированной функцией толстой кишки, тогда как во 2 группе - в 34,6 % (компенсированная) и 3 группе - в 41,5 % (субкомпенсированная) случаев. Независимо от степени нарушения моторно-кинетической функции толстой кишки, у всех пациентов выявлялась 3-я степень дисбиоза. Проведение обучающих программ, дающих знание о физиологических особенностях толстой кишки, оказывало положительное влияние на приверженность пациентов к соматической и фармакопсихологической терапии

A Dissipative-Particle-Dynamics Model for Simulating Dynamics of Charged Colloid

A mesoscopic colloid model is developed in which a spherical colloid is represented by many interacting sites on its surface. The hydrodynamic interactions with thermal fluctuations are taken accounts in full using Dissipative Particle Dynamics, and the electrostatic interactions are simulated using Particle-Particle-Particle Mesh method. This new model is applied to investigate the electrophoretic mobility of a charged colloid under an external electric field, and the influence of salt concentration and colloid charge are systematically studied. The simulation results show good agreement with predictions from the electrokinetic theory.Comment: 17 pages, 8 figures, submitted to the proceedings of High Performance Computing in Science & Engineering '1

Phenotypic and Molecular-Genetic Peculiarities of Yersinia pestis Strains from Trans-Baikal Steppe Plague Focus

The paper contains the data on the complex phenotypic and genotypic characteristics of Yersinia pestisstrains isolated in Trans-Baikal steppe plague focus before and after the succession of the main carrier which took place in the 1960s. Based on the PCR-analysis and multilocus sequence typing of glpD, melB, napA, rhaA, and iclR genes, encoding differentially significant properties such as glycerin, melibiose, rhamnose fermentation, isocitrate lyase production, and denitrification activity, developed are the proofs of affiliation of the studied strains to the biovariant antiqua of the plague agent main subspecies. Multilocus VNTR-analysis by seven locuses of variable tandem repeats – ms01, ms04, ms06, ms07, ms46, ms62 – has been used to establish genetic relations between the strains. Thus on the basis of the results obtained, it is established that the strains of the plague agent, isolated in the Trans-Baikal steppe focus in various periods of its existence, form one common branch on the phylogenetic tree of Y. pestis evolution