49 research outputs found

    The effect of water dynamics on conformation changes of albumin in pre-denaturation state:photon correlation spectroscopy and simulation

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    Water is essential for protein three-dimensional structure, conformational dynamics, and activity. Human serum albumin (HSA) is one of major blood plasma proteins, and its functioning is fundamentally determined by the dynamics of surrounding water. The goal of this study is to link the conformational dynamics of albumin to the thermal motions in water taking place in the physiological temperature range. We report the results of photon correlation spectroscopy and molecular dynamics simulations of HSA in aqueous solution. The experimental data processing produced the temperature dependence of the HSA hydrodynamic radius and its zeta potential. Molecular dynamics reproduced the results of experiments and revealed changes in the secondary structure caused by the destruction of hydrogen bonds in the macromolecule's globule

    Influence of irradiation on the phase equilibrium parameters in liquids

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    The work is dedicated to the investigation of irradiation influence on those properties of liquid systems, which are defined by the change of chemical potential of the liquid and its components under the influence of irradiation. It was shown that irradiation of the coexistent phases at the stationary state leads to the shift of phase transition point parameters. The shift of the temperature and pressure of the phase transition was obtained for the first order phase transitions under the influence of irradiation. Both entropy and energetic factors were included in chemical potential of the regarded system. The main regularities of irradiation influence on the solubility of solid in liquids were obtained

    Quasielastic scattering of slow-neutron in water-alcohol solutions

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    Research of molecules dynamics of solutions “water - propyl alcohol” of different concentration at the temperature 281 K is conducted by the method of slow-neutron quasi-elastic scattering. There were experimentally exposed the feature of effective self-diffusion coefficient of molecules of the indicated solutions. Based on the time- scale hierarchy the division of selfdiffusion coefficient to one-particle and collective contributions was conducted, and the time of the molecules settled life in position of equilibrium was calculated. There were also exposed the feature of self-diffusion concentration dependence of coefficient of self-diffusion and his selfpart contribution, namely: presence of two minimums is in the areas of concentrations (0,04 ÷ 0,05) of mass fraction and (0,18 ÷ 0,22) m.c. of the alcohol and continuous character of diffusion at concentrations higher then 0,4 m.c. of the alcohol. It is shown that the indicated concentration areas correspond the certain local structures of investigational solution

    Retrospective analysis of junior female handball players’ priorities

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    Purpose: fulfillment of retrospective analysis of junior female handball players’ tactic priorities. Material: in the research junior female handball players of 15-16 yrs age (n=60) participated. The researches were conducted in 2006, 2010 and 2016 on the base of sport schools and physical culture colleges of Ukraine. We used author’s programs «Balltest» and «Handball skills». Results: indicators of junior female handball players’ abilities and tactical thinking effectiveness in different periods of the research were received. Correlations of these indicators with physical potentials and throw fitness point at tactical priorities of the players. Comparative characteristic showed that junior female handball players of 2016 year of the research had better abilities for solution of complex team tasks with low sensor indicators. We found handball players’ preferences to defensive and attacking actions in central zone of site. Conclusions: by universal character of tactic priorities junior female handball players of 2016 year of the research yield to the players of 2006 and 2010 years of the research. Junior female handball players of 2016 year of the research prevail in successful mental solution of position defense tactic tasks, especially in readiness to act as supporters

    Non-local competition drives both rapid divergence and prolonged stasis in a model of speciation in populations with degenerate resource consumption

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    <p>Abstract</p> <p>The theory of speciation is dominated by adaptationist thinking, with less attention to mechanisms that do not affect species adaptation. Degeneracy – the imperfect specificity of interactions between diverse elements of biological systems and their environments – is key to the adaptability of populations. A mathematical model was explored in which population and resource were distributed one-dimensionally according to trait value. Resource consumption was degenerate – neither strictly location-specific nor location-independent. As a result, the competition for resources among the elements of the population was non-local. Two modeling approaches, a modified differential-integral Verhulstian equation and a cellular automata model, showed similar results: narrower degeneracy led to divergent dynamics with suppression of intermediate forms, whereas broader degeneracy led to suppression of diversifying forms, resulting in population stasis with increasing phenotypic homogeneity. Such behaviors did not increase overall adaptation because they continued after the model populations achieved maximal resource consumption rates, suggesting that degeneracy-driven distributed competition for resources rather than selective pressure toward more efficient resource exploitation was the driving force. The solutions were stable in the presence of limited environmental stochastic variability or heritable phenotypic variability. A conclusion was made that both dynamic diversification and static homogeneity of populations may be outcomes of the same process – distributed competition for resource not affecting the overall adaptation – with the difference between them defined by the spread of trait degeneracy in a given environment. Thus, biological degeneracy is a driving force of both speciation and stasis in biology, which, by themselves, are not necessarily adaptive in nature.</p
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