Microphase Separation within a Comb Copolymer with Attractive Side Chains: A Computer Simulation Study

Computer simulation modelling of a flexible comb copolymer with attractive interactions between the monomer units of the side chains is performed. The conditions for the coil-globule transition, induced by the increase of attractive interaction, ε, between side chain monomer units, are analysed for different values of the number of monomer units in the backbone, N, in the side chains, n, and between successive grafting points, m. It is shown that the coil-globule transition of such a copolymer corresponds to a first-order phase transition. The energy of attraction (ε) required for the realisation of the coil-globule transition decreases with increasing n and decreasing m. The coil-globule transition is accompanied by significant aggregation of side chain units. The resulting globule has a complex structure. In the case of a relatively short backbone (small value of N), the globule consists of a spherical core formed by side chains and an enveloping shell formed by the monomer units of the backbone. In the case of long copolymers (large value of N), the side chains form several spherical micelles while the backbone is wrapped on the surfaces of these micelles and between them.

Teratomorphism of pollen of Larix sibirica Ledeb. (Pinaceae Lindl.) in the Arctic urbanized territory

This article presents data of palynological research of Larix sibirica Ledeb. (Pinaceae Lindl) in the Arctic climate of Murmansk city, located in the Far North of Russia. The purpose of this study is to research the teratogenesis of the Larix sibirica pollen in the conditions of the Arctic climate and technogenic pollution of the city of Murmansk and holding the palynoindication of the environment. In the tested samples of pollen of L. sibirica, five morphological anomalies of the development were defined: pollen without protoplast, with plasmolysed protoplast, with damaged exine, giant pollen grains and dwarfed. The proportion of teratomorphs in the samples varies from 76 to 81%, which is above the control values of 2.5 – 3 times. Most of the abnormal grains are represented by pollen with plasmolysed protoplast (58 – 64%) and without protoplast (11 – 18%). Giant, dwarf pollen grains and pollen with exine damage are much less common. High level of teratogenesis of L. sibirica allows us to draw a conclusion about the critical level of pollution of the city environment

Trapped modes in thin and infinite ladder like domains. Part 1 : existence results

International audienceThe present paper deals with the wave propagation in a particular two dimensional structure, obtained from a localized perturbation of a reference periodic medium. This reference medium is a ladder like domain, namely a thin periodic structure (the thickness being characterized by a small parameter $\epsilon > 0$) whose limit (as $\epsilon$ tends to 0) is a periodic graph. The localized perturbation consists in changing the geometry of the reference medium by modifying the thickness of one rung of the ladder. Considering the scalar Helmholtz equation with Neumann boundary conditions in this domain, we wonder whether such a geometrical perturbation is able to produce localized eigenmodes. To address this question, we use a standard approach of asymptotic analysis that consists of three main steps. We first find the formal limit of the eigenvalue problem as the $\epsilon$ tends to 0. In the present case, it corresponds to an eigenvalue problem for a second order differential operator defined along the periodic graph. Then, we proceed to an explicit calculation of the spectrum of the limit operator. Finally, we prove that the spectrum of the initial operator is close to the spectrum of the limit operator. In particular, we prove the existence of localized modes provided that the geometrical perturbation consists in diminishing the width of one rung of the periodic thin structure. Moreover, in that case, it is possible to create as many eigenvalues as one wants, provided that ε is small enough. Numerical experiments illustrate the theoretical results

Mechanism of proteolysis in matrix metalloproteinase-2 revealed by QM/MM modeling

The mechanism of enzymatic peptide hydrolysis in matrix metalloproteinase-2 (MMP-2) was studied at atomic resolution through quantum mechanics/molecular mechanics (QM/MM) simulations. An all-atom three-dimensional molecular model was constructed on the basis of a crystal structure from the Protein Data Bank (ID: 1QIB), and the oligopeptide Ace-Gln-Gly∼Ile-Ala-Gly-Nme was considered as the substrate. Two QM/MM software packages and several computational protocols were employed to calculate QM/MM energy profiles for a four-step mechanism involving an initial nucleophilic attack followed by hydrogen bond rearrangement, proton transfer, and C—N bond cleavage. These QM/MM calculations consistently yield rather low overall barriers for the chemical steps, in the range of 5–10 kcal/mol, for diverse QM treatments (PBE0, B3LYP, and BB1K density functionals as well as local coupled cluster treatments) and two MM force fields (CHARMM and AMBER). It, thus, seems likely that product release is the rate-limiting step in MMP-2 catalysis. This is supported by an exploration of various release channels through QM/MM reaction path calculations and steered molecular dynamics simulations

Adsorption and Reduction of NO on Tin(W)Oxide Doped with Chromium(lll) Oxide

Functional Reactive Programming (FRP) is claimed to be a good choice for event handling applications. Current object- oriented telecom applications are known to suffer from additional complexity due to event handling code. In this paper we study the maintainability of FRP programs in the tele- com domain compared to traditional object-oriented programming (OOP), with the motivation that higher maintainability increases the service quality and decreases the costs. Two implementations of the same procedure are created: one using Haskell and the reactive-banana FRP frame- work and one using C++ and the OOP paradigm. Four software experts each with over 20 years of experience and three development engineers working on a product subject to study were engaged in evaluations, based on a questionnaire involving five different aspects of maintainability. The evaluations indicate a higher maintainability profile for FRP compared with OOP. This is confirmed by a more detailed analysis of the code size. While performance was not a main criteria, a preliminary evaluation shows that the OOP prototype is 8-10 times faster than the FRP prototype in the current (non-optimised) implementations.Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or re-publish, to post on servers or to redistribute to lists, requires prior specific permissionand/or a fee. Request permissions from [email protected].</p

The format of training family doctors on palliative care in the Dnipropetrovsk region.

The first global palliative care resolution WHA 67.19 has been developed recently, in 2014, where the need to improve access to palliative care around the world is first declared. In the article, the authors analyzed the change trends and the state of the medical care delivery system for incurable patients in the world and Ukraine. As the civilization of the state and the humanity of society as a whole is assessed by the level of PHC provision in today's world, this problem has attracted the attention of central (Ukraine) and regional (Dnipro city) government bodies, which was reflected in the search for new medical and educational initiatives. The need of the time is the need to focus the attention of family doctors on the issue that palliative care is a qualification component of their daily work, which will help to remove incurable patients from the periphery of attention of their multicomponent work, and will also help to clearly build the interaction between the primary and secondary link, in particular, with hospice departments of specialized hospitals. In particular, the experience of implementing a joint project of a new format for training family doctors on palliative care issues, realized by the Department of Family Medicine of the SE “DMA” and the Municipal non-commercial enterprise "City Clinical Hospital No. 2” of Dnipro City Council is described. In­novative forms of conducting classes help to expand the boundaries of the possibilities of teaching problematic issues of palliative medicine, which account for only 0.6% of instructional time in the existing program of training family doctors of secondary specialization, and the multicomponent format for studying palliative care issues, implemented, inter alia, with support of Director of the Municipal non-commercial enterprise "City Clinical Hospital No. 2” of Dnipro City Council (visiting hospice and palliative departments delivering secondary level of medical care assistance, a structured regulatory unit for the provision of PHC in Ukraine, working out of patients’ routing issues, interactive teaching methods, etc.) leaves in the memory of physician-trainees not only the essential content, but also a deep emotional trace, which helps to increase the motivation of the physician trainees, improves coordination between primary and secondary palliative care and improves the quality of training

Exchange Rate Regime in Russia, Evaluation and Recommendations

This paper studies exchange rate choice in Russia with respect to social, economic and political determinants. The study deliberately narrowed the scope of the discussion to two extreme cases, i.e. fixed and floating exchange rate. Today Russia applies managed floating exchange rate arrangement and it is important to determine the direction of the further monetary policy development either towards fixed or floating exchange rate. The paper argues that the logical extension of the historical trend is a shift to an independently floating exchange rate arrangement

Tales of resilience: voices from detention and imprisonment in Russia

As the exposure to state violence could have long-term negative consequences onthe survivors, we analyzed which optics and measures could be used regardless of thevulnerabilities of the individual, their social status and institutional context. We examine the ways in which law enforcement system challenges individuals and measures used to practice resilience. We use the concept of resilience withintorturing environment to achieve our goal. Various actors of Russian law enforcementand penitentiary systems – detainees and prisoners, their family members, human rights activists, state agents etc. – participated in semi-structured in-depth interviews, which we coded basing on grounded theory. Measures employed by survivors to exercise resilience involve regaining bodily control (both by exercise and self-harm), having projections for future (by threats of legal prosecution or publicity), exploiting bureaucracy to one’s advantage, controlling information flow (by bluffing), controlling material evidence, employing allies and preserving the meaning of “normal self”.We believe that our findings can have practical applications, e.g. for preventing some of the negative consequences of torture by training vulnerable individuals to employ resilient strategies. Describing the way to interpret the power imbalances inherent to the torture environment might also be helpful for appreciating even the smallest acts, including the choice not to act

Comparative study of technologies for extraction of biologically active substances from the raw material of animal origin

Technologies of isolation and concentration of biologically active substances, developed in the middle of the 20th century, need adjustment and adaptation to modern conditions both to increase the activity of substances and for greater economic efficiency. The aim of the research is the comparison of dynamics of biologically active compounds extraction from porcines pancreas in two methods: the saline method based on 0.9% sodium chloride solution, and the acidic method based on 2.4% trichloroacetic acid solution. Also the purpose of research is to assess the possibilities for further optimization of technologies. The total protein concentration based on the biuret reaction in the samples taken during the extraction, as well as the calculation and analysis of the point degrees and rates of extraction are chosen as the controlled parameters. Local maxima of the protein yields into the extractant media at the 60th, 135th and 255th minute were recorded during saline extraction; and at the 75th and 135th minute during acid extraction. Also the proteomic profile of the extracts was studied. Wide range of compounds with molecular weight of less than 52 kDa was found in extracts based on physiological saline solution, and protein substances of whole presented range of molecular weights in trichloroacetic acid based extracts were considered. The predominance of low molecular weight protein fraction of interest was noted also in this method of extraction in comparison with the other methods of extraction. According to the UniProt database, we assume availability of probable compounds with a molecular weight of less than 30 kDa in the purified acidic extract. The presence of some proteins absent in the final saline extract was noted. The acidic erythrograms showed a weak degrading effect of both types of extracts on the membranes of rat erythrocytes, as well as the cytoprotective effect of acidic ultrafiltrates (less than 3 kDa). The obtained results prove a better efficiency of trichloroacetic acid extraction method used for obtaining a mixture of a wide range of compounds, including biologically active substances of low molecular weight