Kinetics of non-ionic surfactant adsorption at a fluid-fluid interface from a micellar solution

The kinetics of non-ionic surfactant adsorption at a fluid-fluid interface from a micellar solution is considered theoretically. Our model takes into account the effect of micelle relaxation on the diffusion of the free surfactant molecules. It is shown that non-ionic surfactants undergo either a diffusion or a kinetically limited adsorption according to the characteristic relaxation time of the micelles. This gives a new interpretation for the observed dynamical surface tension of micellar solutions.Comment: 4 page

Исследование работы стеклопластиковых крепежных элементов в стеновых конструкциях

The article is devoted to the study of pull-out tests of fiberglass plastic dowels installed in the walls made of lightweight concrete. The authors have undertaken experimental tests of anchors in use on the construction site and conducted analysis of test results.Работа посвящена исследованию характеристик сцепления композитных стеклопластиковых дюбелей с легким бетоном. Авторами проведены экспериментальные испытания анкеров в натурных условияx на строительной площадке и выполнен анализ результатов испытаний

Влияние железооксидных пигментов на физико-механические свойства бетона

В статье представлены результаты комплексных исследований по изучению влияния пигментов на прочностные характеристики окрашенного мелкозернистого бетона в разные сроки твердения и на скорость образования высолов. В качестве объекта исследования были взяты пигменты — продукты глубокой переработки отходов обогащения асбестовых руд Баженовского месторождения Свердловской области. Несколько серий экспериментов выявили, что в сравнении с китайскими аналогами они обладают рядом технологических преимуществ: лучшей диспергируем остью и однородностью гранулометрического состава, что позволяет им быстро и равномерно распределяться по всему объему бетона и давать более равномерную окраску изделий.The article presents the resulte o f complex studies on the effect of pigments on the strength characteristics of the colour of fine-grained concrete in different periods of hardening and the speed of leaching. As the object of research were taken pigments—product of deep processing of a waste of enrichment of asbestos ores Bagenovofield Sverdlovsk region. Several series of ехрегітепѣ have revealed, that in comparison with Chinese counterparts, they have a number of technological advantages: the best dispersion and homogeneity of the granulometric composition, that allows them to quickly and evenly distributed throughout the volume of concrete and to give a more uniform colouringproducts

Dynamics of ions in the selectivity filter of the KcsA channel

The statistical and dynamical properties of ions in the selectivity filter of the KcsA ion channel are considered on the basis of molecular dynamics (MD) simulations of the KcsA protein embedded in a lipid membrane surrounded by an ionic solution. A new approach to the derivation of a Brownian dynamics (BD) model of ion permeation through the filter is discussed, based on unbiased MD simulations. It is shown that depending on additional assumptions, ion’s dynamics can be described either by under-damped Langevin equation with constant damping and white noise or by Langevin equation with a fractional memory kernel. A comparison of the potential of the mean force derived from unbiased MD simulations with the potential produced by the umbrella sampling method demonstrates significant differences in these potentials. The origin of these differences is an open question that requires further clarifications

Cellular and clinical impact of Haploinsufficiency for genes involved in ATR signaling

Ataxia telangiectasia and Rad3-related (ATR) protein, a kinase that regulates a DNA damage-response pathway, is mutated in ATR-Seckel syndrome (ATR-SS), a disorder characterized by severe microcephaly and growth delay. Impaired ATR signaling is also observed in cell lines from additional disorders characterized by microcephaly and growth delay, including non-ATR-SS, Nijmegen breakage syndrome, and MCPH1 (microcephaly, primary autosomal recessive, 1)-dependent primary microcephaly. Here, we examined ATR-pathway function in cell lines from three haploinsufficient contiguous gene-deletion disorders--a subset of blepharophimosis-ptosis-epicanthus inversus syndrome, Miller-Dieker lissencephaly syndrome, and Williams-Beuren syndrome--in which the deleted region encompasses ATR, RPA1, and RFC2, respectively. These three genes function in ATR signaling. Cell lines from these disorders displayed an impaired ATR-dependent DNA damage response. Thus, we describe ATR signaling as a pathway unusually sensitive to haploinsufficiency and identify three further human disorders displaying a defective ATR-dependent DNA damage response. The striking correlation of ATR-pathway dysfunction with the presence of microcephaly and growth delay strongly suggests a causal relationship

Methods for leptospirosis laboratory diagnostics: features of experimentation, advantages and limitations

Leptospirosis is a cosmopolitan natural-focal disease representing a serious problem for the majority of the countries in the world including the Russian Federation because this infection causes a serious economic and social damage. Modern laboratory diagnostics of leptospiroses is based on a complex of bacteriological, immunological and molecularbiological methods used in various combinations depending on the problems and possibilities of the laboratories. At all variety, many methods are not applied in practice and the gold standard still remains the routine serological method. Disease diagnostics is based on a set of epidemiological, epizootological, clinical and pathoanatomical data with obligatory laboratory verification of the diagnosis. However often laboratory verification is retrospective or in general absent. For achievement of the best results in leptospirosis diagnostics, it is necessary to improve the available laboratory methods and to use it in practice. Especial attention should be given to introduction of new molecular technologies that simplify laboratory diagnostics and expand its possibilities

MODERN TRENDS OF THE SPREADING LEPTOSPIROSIS OVERSEAS

In this study the increased number of the imported cases from endemic countries or occurring of the disease in earlier unknown natural leptospirosis foci in the world among participants of various extreme competitions, hostilities and travelers was revealed at analysis of the epidemiological leptospirosis situation. New human risk groups subjected to infection were determined

Direct knock-on of desolvated ions governs strict ion selectivity in K+ channels

The seeming contradiction that K+ channels conduct K+ ions at maximal throughput rates while not permeating slightly smaller Na+ ions has perplexed scientists for decades. Although numerous models have addressed selective permeation in K+ channels, the combination of conduction efficiency and ion selectivity has not yet been linked through a unified functional model. Here, we investigate the mechanism of ion selectivity through atomistic simulations totalling more than 400 μs in length, which include over 7,000 permeation events. Together with free-energy calculations, our simulations show that both rapid permeation of K+ and ion selectivity are ultimately based on a single principle: the direct knock-on of completely desolvated ions in the channels' selectivity filter. Herein, the strong interactions between multiple 'naked' ions in the four filter binding sites give rise to a natural exclusion of any competing ions. Our results are in excellent agreement with experimental selectivity data, measured ion interaction energies and recent two-dimensional infrared spectra of filter ion configurations