Solvation dynamics in monohydroxy alcohols: Agreement between theory and different experiments

Recently three different experimental studies on ultrafast solvation dynamics in monohydroxy straight-chain alcohols (C-1-C-4) have been carried out, with an aim to quantify the time constant (and the amplitude) of the ultrafast component. The results reported are, however, rather different from different experiments. In order to understand the reason for these differences, we have carried out a detailed theoretical study to investigate the time dependent progress of solvation of both an ionic and a dipolar solute probe in these alcohols. For methanol, the agreement between the theoretical predictions and the experimental results [Bingemann and Ernsting J. Chem. Phys. 1995, 102, 2691 and Horng et al. J: Phys, Chern, 1995, 99, 17311] is excellent. For ethanol, propanol, and butanol, we find no ultrafast component of the time constant of 70 fs or so. For these three liquids, the theoretical results are in almost complete agreement with the experimental results of Horng et al. For ethanol and propanol, the theoretical prediction for ionic solvation is not significantly different from that of dipolar solvation. Thus, the theory suggests that the experiments of Bingemann and Ernsting and those of Horng et al. studied essentially the polar solvation dynamics. The theoretical studies also suggest that the experimental investigations of Joo et al. which report a much faster and larger ultrafast component in the same series of solvents (J. Chem. Phys. 1996, 104, 6089) might have been more sensitive to the nonpolar part of solvation dynamics than the polar part. In addition, a discussion on the validity of the present theoretical approach is presented. In this theory the ultrafast component arises from almost frictionless inertial motion of the individual solvent molecules in the force field of its neighbors.

Biological water: Femtosecond dynamics of macromolecular hydration

The unique features of a macromolecule and water as a solvent make the issue of solvation unconventional, with questions about the static versus dynamic nature of hydration and the, physics of orientational and translational diffusion at the boundary. For proteins, the hydration shell that covers the surface is critical to the stability of its structure and function. Dynamically speaking, the residence time of water at the surface is a signature of its mobility and binding. With femtosecond time resolution it is possible to unravel the shortest residence times which are key for the description of the hydration layer, static or dynamic. In this article we review these issues guided by experimental studies, from this laboratory, of polar hydration dynamics at the surfaces of two proteins (Subtilisin Carlsberg (SC) and Monellin). The natural probe tryptophan amino acid was used for the interrogation of the dynamics, and for direct comparison we also studied the behavior in bulk water - a complete hydration in 1 ps. We develop a theoretical description of solvation and relate the theory to the experimental observations. In this - theoretical approach, we consider the dynamical equilibrium in the hydration shell, defining the rate processes for breaking and making the transient hydrogen bonds, and the effective friction in the layer which is defined by the translational and orientational motions of water molecules. The relationship between the residence time of water molecules and the observed slow component in solvation dynamics is a direct one. For the two proteins studied, we observed a "bimodal decay" for the hydration correlation function, with two primary relaxation times: ultrafast, typically 1 ps or less, and longer, typically 15-40 ps, and both are related to the residence time at the protein surface, depending on the binding energies. We end by making extensions to studies of the denatured state of the protein, random coils, and the biomimetic micelles, and conclude with our thoughts on the relevance of the dynamics of native structures to their functions.

Acto-myosin contractility rotates the cell nucleus

The nucleus of the eukaryotic cell functions amidst active cytoskeletal �laments, but its response to the stresses carried by these �laments is largely unexplored. We report here the results of studies of the translational and rotational dynamics of the nuclei of single �broblast cells, with the e�ects of cell migration suppressed by plating onto �bronectin-coated micro-fabricated patterns. Patterns of the same area but di�erent shapes and/or aspect ratio were used to study the e�ect of cell geometry on the dynamics. On circles, squares and equilateral triangles, the nucleus undergoes persistent rotational motion, while on high-aspect-ratio rectangles of the same area it moves only back and forth. The circle and the triangle showed respectively the largest and the smallest angular speed. We show that our observations can be understood through a hydrodynamic approach in which the nucleus is treated as a highly viscous inclusion residing in a less viscous uid of orientable �laments endowed with active stresses. Lowering actin contractility selectively by introducing blebbistatin at low concentrations drastically reduced the speed and persistence time of the angular motion of the nucleus. Time-lapse imaging of actin revealed a correlated hydrodynamic ow around the nucleus, with pro�le and magnitude consistent with the results of our theoretical approach. Coherent intracellular ows and consequent nuclear rotation thus appear to be a generic property that cells must balance by speci�c mechanisms in order to maintain nuclear homeostasis

Actomyosin contractility rotates the cell nucleus

The cell nucleus functions amidst active cytoskeletal filaments, but its response to their contractile stresses is largely unexplored. We study the dynamics of the nuclei of single fibroblasts, with cell migration suppressed by plating onto micro-fabricated patterns. We find the nucleus undergoes noisy but coherent rotational motion. We account for this observation through a hydrodynamic approach, treating the nucleus as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active stresses. Lowering actin contractility selectively by introducing blebbistatin at low concentrations drastically reduced the speed and coherence of the angular motion of the nucleus. Time-lapse imaging of actin revealed a correlated hydrodynamic flow around the nucleus, with profile and magnitude consistent with the results of our theoretical approach. Coherent intracellular flows and consequent nuclear rotation thus appear to be an intrinsic property of cells.

Correlation between thermodynamic anomalies and pathways of ice nucleation in supercooled water

The well-known classical nucleation theory (CNT) for the free energy barrier towards formation of a nucleus of critical size of the new stable phase within the parent metastable phase fails to take into account the influence of other metastable phases having density/order intermediate between the parent metastable phase and the final stable phase. This lacuna can be more serious than capillary approximation or spherical shape assumption made in CNT. This issue is particularly significant in ice nucleation because liquid water shows rich phase diagram consisting of two (high and low density) liquid phases in supercooled state. The explanations of thermodynamic and dynamic anomalies of supercooled water often invoke the possible influence of a liquid-liquid transition between two metastable liquid phases. To investigate both the role of thermodynamic anomalies and presence of distinct metastable liquid phases in supercooled water on ice nucleation, we employ density functional theoretical approach to find nucleation free energy barrier in different regions of phase diagram. The theory makes a number of striking predictions, such as a dramatic lowering of nucleation barrier due to presence of a metastable intermediate phase and crossover in the dependence of free energy barrier on temperature near liquid-liquid critical point. These predictions can be tested by computer simulations as well as by controlled experiments. (C) 2014 AIP Publishing LLC.

Interactome analyses of Salmonella pathogenicity islands reveal SicA indispensable for virulence

Background: Serovars of Salmonella enterica, namely Typhi and Typhimurium, reportedly, are the bacterial pathogens causing systemic infections like gastroenteritis and typhoid fever. To elucidate the role and importance in such infection, the proteins of the Type III secretion system of Salmonella pathogenicity islands and two component signal transduction systems, have been mainly focused. However, the most indispensable of these virulent ones and their hierarchical role has not yet been studied extensively. Results: We have adopted a theoretical approach to build an interactome comprising the proteins from the Salmonella pathogeneicity islands (SPI) and two component signal transduction systems. This interactome was then analyzed by using network parameters like centrality and k-core measures. An initial step to capture the fingerprint of the core network resulted in a set of proteins which are involved in the process of invasion and colonization, thereby becoming more important in the process of infection. These proteins pertained to the Inv, Org, Prg, Sip, Spa, Ssa and Sse operons along with chaperone protein SicA. Amongst them, SicA was figured out to be the most indispensable protein from different network parametric analyses. Subsequently, the gene expression levels of all these theoretically identified important proteins were confirmed by microarray data analysis. Finally, we have proposed a hierarchy of the proteins involved in the total infection process. This theoretical approach is the first of its kind to figure out potential virulence determinants encoded by SPI for therapeutic targets for enteric infection. Conclusions: A set of responsible virulent proteins was identified and the expression level of their genes was validated by using independent, published microarray data. The result was a targeted set of proteins that could serve as sensitive predictors and form the foundation for a series of trials in the wet-lab setting. Understanding these regulatory and virulent proteins would provide insight into conditions which are encountered by this intracellular enteric pathogen during the course of infection. This would further contribute in identifying novel targets for antimicrobial agents. (C) 2014 Elsevier Ltd. All rights reserved.

Prevalência da Câmara dos Deputados no processo legislativo bicameral : a Lei de improbidade administrativa

Analisa a Constituição Federal e as Leis Ordinárias editadas em 2011 para saber se existe a prevalência de uma das Casas do Congresso Nacional na elaboração das leis. O estudo pretende, a partir da abordagem teórica e da análise das legislações publicadas, observando o processo legislativo bicameral para deliberação dos projetos, verificar as consequências para a definição do texto final das leis publicadas. Para tanto, propõe-se realizar estudo sobre o Poder Legislativo no Brasil e o modelo de sistema bicameral adotado. Também são analisadas todas as Constituições editadas no Brasil para saber os aspectos históricos e políticos em sua elaboração e os efeitos na definição das atribuições das Casas do Congresso Nacional, com repercussões no processo legislativo. É realizada a análise da tramitação legislativa da Lei de Improbidade Administrativa, expondo os textos adotados pelas Casas, com a definição do texto encaminhado para transformação em norma jurídica.

El salto a los tres años en psicomotricidad : observación del comportamiento psicomotor infantil

[ES] El objetivo de esta investigación es evaluar la actividad de saltar de un grupo escolar natural de 15 criaturas entre los dos y los cuatro años en el contexto de la Práctica Psicomotriz Aucouturier. La perspectiva teórica adoptada ha sido la teoría psicogenética y dialéctica de Henri Wallon. Según ésta, saltar es un automatismo natural regulado por el aparato funcional del equilibrio que se aprende en la primera infancia. La metodología utilizada ha sido la observacional. El diseño es nomotético, de seguimiento y multidimensional, y el instrumento de observación es el formato de campo "el salto en psicomotricidad durante el tercer año de vida". Los resultados, obtenidos mediante la aplicación prospectiva del análisis secuencial de retardos, informan sobre la adquisición del automatismo o proceso de aprendizaje, sobre el contenido del mismo o manejo del vértigo y sobre su resultante conjunta o tipos básicos de salto en psicomotricidad, sus características y su evolución.

Gewinnmaximierung der Fischerei schützt den Dorsch der westlichen Ostsee vor Überfischung – Nur ein theoretischer Ansatz ?

Profit maximization in fishery protects cod of western Baltic Sea against overfishing – Only a theoretical approach? The frame for the management of fish stocks politically given contains – apart from ecological and social goals – also an economic goal, which is considered here in particular. From the point of view of fishery enterprises the main management goal for the exploitation of fish stocks is the maximization of profit. There are models for the yield optimization since long time. They are mainly used so far to optimize fishing mortality. Here the Beverton and Holt yield model was used. Apart from the optimization of fishing effort the model was used to optimize age of first capture and thus mesh opening. Starting point of the considerations is a given age group of a fish stock. If this age group is completely fished the yield obtained from this age group is maximized. The investigations show that the term overfishing is not exclusively linked as frequently assumed with a too large fishing mortality, but likewise with a mismatch of the mesh opening. For the calculated example Baltic cod data are used. At present the cod is caught far from reaching its mass optimum. Therefore, the profit of fishery enterprises can in the long term be considerably increased by the optimization of the mesh opening. During the conversion from the state of the art to fishing with optimised mesh sizes, however, a loss of profit has to be expected. The title of the paper sounds provocative. However, the stock of the Baltic Sea cod is better protected by a long-term maximum-profit oriented exploitation than by the precautionary approach applied now.

Effects of volumetric allocation on heave response of semisubmersible in deep sea

The configuration of semisubmersibles consisting of pontoons and columns and their corresponding heave motion response in incident progressive waves are examined. The purpose of the present study is to provide a theoretical approach to estimating the effects of volumetric allocation on natural period and response amplitude operator (RAO) in heave motion. We conclude that the amplitude of heave motion response can be considerably suppressed by appropriately adjusting volumetric allocation so that the natural heave period keeps away from the range of wave energy. The theoretical formulae are found in good agreement with the corresponding computational results by WAMIT.

Uma crítica fenomenológica à tese de Kant sobre o Ser: da linguagem-utensílo à linguagem-constituição

Este trabalho visa realizar os primeiros passos de um projeto mais longo, cujo objetivo é determinar o sentido daquilo que entendemos como pergunta pelo sentido do ser; junto a isso, se tem aqui igualmente o propósito de pensar a metodologia que acaso venha a ser adequada, isto é, o tratamento específico que possa alguma vez dar a tal questionamento um desenvolvimento legítimo. O caminho por nós adotado partirá de Kant por motivos estratégicos, principalmente pela razão de encontrarmos aí uma tese declarada sobre ser, que lhe concede um sentido unitário: ao comentá-la, reconstruindo-a por meio da apresentação de alguns de seus momentos, estaremos nos utilizando da mesma para apontar aquilo que acreditamos constituir uma corrupção de sentido nas suas próprias bases, permitindo compreender as dificuldades lançadas pela questão que, assim nos parece, são as mesmas que terminam por gerar as confusões que perfazem a própria história da metafísica. Isto significa que nossa discussão do caso kantiano - embora vise diretamente a filosofia crítica e todo projeto de uma teoria das faculdades - deverá cunhar resultados mais amplos, já mesmo porque, a partir dela, viremos mesmo a afirmar a total inadequação de uma abordagem do sentido do ser sob o ponto de vista do comportamento teórico. Por oposição a ele, procuraremos demonstrar que ser só pode ser abordado no interior de um campo de sentido que se apresente como o que chamaremos de atividade descritiva ou, poderíamos igualmente dizer, uma atividade de mostração. Este último ponto, conclusivo somente quanto à parte do caminho que nosso projeto mais geral nos exige percorrer, será explicitado com a ajuda de alguns dos conceitos apresentados por Husserl em suas Investigações Lógicas.

Design and analysis of a kind of large flattened mode optical fibre

In this paper, a refractive index pro. le design enabling us to obtain a. at modal field around the fibre centre is investigated. The theoretical approach for designing such multilayer large flattened mode (LFM) optical fibres is presented. A comparison is made between the properties of a three-layer LFM structure and a standard step-index pro. le with the same core size. The obtained results indicate that the effective area of the LFM fibre is about twice as large as that of the standard step-index fibre, but the LFM fibre has less effective ability to filter out the higher order modes than the standard step-index fibre with the same bending radius.

Desenvolvimento de um sistema de detecção fotoacústico utilizando dois microfones: aplicações em medidas de difusividade térmica

Neste trabalho, desenvolveu-se um sistema de detecção fotoacústico para medidas simultâneas e independentes dos sinais fotoacústicos dianteiro e traseiro, utilizando dois microfones e um único feixe de excitação. Utiliza-se a diferença de fase entre estes sinais para a determinação da difusividade térmica de materiais, com base na abordagem teórica da técnica da Diferença de Fase dos Dois Feixes (T2F). Na metodologia apresentada não há a necessidade de se alternar o feixe de excitação entre as faces da amostra. Esta característica torna mais rápido o procedimento de medida e simplifica o monitoramento automatizado de processos dinâmicos que afetam a difusividade térmica do material, como a cura de resinas poliméricas. É apresentado o procedimento utilizado para determinar a diferença entre as fases intrínsecas dos microfones e o método empregado para compensar tal diferença e, assim, obter a defasagem entre os sinais fotoacústicos dianteiro e traseiro. O sistema de detecção desenvolvido é avaliado em medidas de difusividade térmica de amostras metálicas (aço inoxidável AISI 304 e aço SAE 1020) e poliméricas (polipropileno e polietileno de baixa densidade). Os resultados obtidos concordam de forma satisfatória com dados disponíveis na literatura. Finalmente, a aplicação do sistema proposto ao monitoramento de cura de amostras de resina epóxi indicou sua potencialidade de acompanhar, em tempo real, este tipo de processo dinâmico.

Initiatives for the improvement of continuous management training

[EN] Purpose. This work aims to present, from the company viewpoint, a structured account of management proposals and practices directed toward improving the intensity and effectiveness of continuous management training (CMT). Design/methodology/approach. The article takes as its main theoretical referents the Theory of Human Capital, the Resource-Based Vision and the contributions made via the new institutional economy with regard to the problems of information asymmetry between companies, employees and training providers and completes the proposals that derive from this theoretical approach. To do this, experience-based contributions are collected from a selection of company training and HR managers from twelve Basque companies characterised by their strong investment in management training. The methodology used was qualitative and obtained by different qualitative techniques: Focus Groups, Nominal Groups and the Delphi Method, which make up the so-called Hybrid Delphi. Findings and implications. The proposals are aimed at the main agents in training activity: training providers, associations and public agents engaged in management training and, particularly, companies themselves. The initiatives seek above all to increase training market transparency, to improve mutual commitments between companies and managers, and to link training and development with culture and strategic management, so that firms make optimal investment in management training. Originality/value. The methodology used is original, and the contributions are consistent with the theory, have a proven practical utility, and are presented in a hierarchy, which facilitates decision making.

O engenho por dentro: cartografia das práticas cotidianas de cuidado em saúde mental dos auxiliares e técnicos de enfermagem na perspectiva da integralidade

Discutem-se os processos de trabalho e de produção do cuidado dos auxiliares e técnicos de enfermagem do Núcleo de Atenção à Crise do Instituto Municipal de Assistência à Saúde Nise da Silveira, no contexto da desinstitucionalização, e seus efeitos na integralidade do cuidado. O foco de análise repousa sobre o cuidado cotidiano prestado por esses profissionais nas unidades de internação psiquiátrica. Buscou-se realizar uma reflexão sobre os aspectos contemporâneos do cotidiano da assistência psiquiátrica e o papel dos hospitais psiquiátricos no atendimento aos pacientes agudos. Para tal objetivou-se, especificamente: contextualizar o IMNS no cenário de saúde mental no município do Rio de Janeiro; descrever as práticas assistenciais de auxiliares e técnicos de enfermagem no cuidado aos pacientes agudos internados; e discutir as práticas de cuidado no contexto da reorientação do modelo hospitalar e suas repercussões na integralidade da assistência em saúde, buscando contradições e aproximações com o discurso da política de saúde mental vigente. Foram abordadas na fundamentação teórica: as questões da prática da equipe de saúde sob o eixo da integralidade, em especial da equipe de enfermagem, e a relação trabalho/saúde/cotidiano na construção dos processos de trabalho e de produção do cuidado da assistência prestada. Como abordagem teórico-metodológica que possibilitou alcançar o objetivo proposto, realizou-se estudo exploratório, de natureza qualitativa, na perspectiva da cartografia, tendo na observação participante seu principal elemento de coleta de dados. O mapeamento das práticas rotineiras de cuidado evidenciou que estas são predominantemente pautadas no modelo asilar, no qual auxiliares e técnicos desempenham suas atividades diárias de modo distanciado dos pacientes e de suas necessidades. Esses profissionais não são vistos como elementos da equipe de saúde mental, e assim, desprestigiados em relação à política de formação e capacitação em saúde mental, assumem o cuidado aos pacientes institucionalizados de modo pouco estruturado, sem levar em consideração os anseios e sofrimentos dos usuários. Acolhimento, vínculo e integralidade fizeram parte do discurso oficial de reorganização da assistência, num contexto macroestrutural, mas ainda não se materializam nas práticas assistenciais da unidade de saúde pesquisada. A importância do estudo está pautada no fornecimento de subsídios para a formulação e implantação de ações que auxiliem na melhoria da gestão do trabalho em saúde mental. Sua justificativa se faz na medida em que essa área é permeada por conflitos e questões que interferem decisivamente na qualidade dos serviços prestados.