Anomalous size-dependence of interfacial profiles between coexisting phases of polymer mixtures in thin film geometry: A Monte-Carlo simulation

The interfacial profile between coexisting phases of a binary mixture (A,B) in a thin film of thickness D and lateral linear dimensions L depends sensitively on both linear dimensions and on the nature of boundary conditions and statistical ensembles applied. These phenomena generic for systems in confined geometry are demonstrated by Monte-Carlo simulations of the bond fluctuation model of symmetric polymer mixtures. Both the canonical and semi-grand-canonical ensemble are studied. In the canonical ensemble, the interfacial width w increases (from small values which are of the same order as the intrinsic profile) like sqrt{D}, before a crossover to a saturation value w_max (w_max^2 proportional to ln L) sets in. In the semi-grand-canonical ensemble, however, one finds the same widths (w proportional to sqrt{D}) as in the canonical ensemble for not too large L, while for large L the interfacial profile is smeared out over a finite fraction of the film thickness (w proportional to D for D -> infinity). We discuss the implications of these findings for the interpretation of both simulations and experiments.Comment: 42 pages, including 15 PS figures, to appear in JC

Prognostic relevance of autophagy-related markers LC3, p62/sequestosome 1, Beclin-1 and ULK1 in colorectal cancer patients with respect to KRAS mutational status

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Interfaces in partly compatible polymer mixtures: A Monte Carlo simulation approach

The structure of polymer coils near interfaces between coexisting phases of symmetrical polymer mixtures (AB) is discussed, as well as the structure of symmetric diblock copolymers of the same chain length N adsorbed at the interface. The problem is studied by Monte Carlo simulations of the bond fluctuation model on the simple cubic lattice, using massively parallel computers (CRAY T3D). While homopolymer coils in the strong segregation limit are oriented parallel to the interface, the diblocks form ``dumbbells'' oriented perpendicular to the interface. However, in the dilute case (``mushroom regime'' rather than ``brush regime''), the diblocks are only weakly stretched. Distribution functions for monomers at the chain ends and in the center of the polymer are obtained, and a comparison to the self consistent field theory is made.Comment: to appear in Physica

Проектирование системы электроснабжения базы по обслуживанию нефтегазодобывающего месторождения

Выпускная квалификационная работа 136 с., 19 рис., 60 табл., 24 источника, 4 приложения. Объектом исследования является ремонтно-механический цех базы по обслуживанию нефтегазодобывающего месторождения. Цель работы: Проектирование системы электроснабжения базы по облуживанию нефтегазодобывающего месторождения. Экономическое обоснование принятых решений. В процессе исследования произведен расчет нагрузок ремонтно-механического цеха и базы в целом с применением различных методов, выбор метода расчета производился на основе исходных данных, а также осуществлен выборThis graduate qualification work includes 136 p., 19 fig., 60 tables, 24 ones in list of references and 4 transcripts. The subject of research is mechanical repair shop of upstream and gas production field operation base. Work objective is energy supply system designing of upstream and gas production field operation base and its business case. In the course of investigations there was estimated a load analysis of upstream and gas production field operation base and its mechanical repair shop by different methods, based on input data. Also there were steps of the equipment selection and its testing of several operations. As a result of investigation the model of such base was engineered, and there was shown its commercial importance and ecological security. Range of application: petro

Monte Carlo Methods for Estimating Interfacial Free Energies and Line Tensions

Excess contributions to the free energy due to interfaces occur for many problems encountered in the statistical physics of condensed matter when coexistence between different phases is possible (e.g. wetting phenomena, nucleation, crystal growth, etc.). This article reviews two methods to estimate both interfacial free energies and line tensions by Monte Carlo simulations of simple models, (e.g. the Ising model, a symmetrical binary Lennard-Jones fluid exhibiting a miscibility gap, and a simple Lennard-Jones fluid). One method is based on thermodynamic integration. This method is useful to study flat and inclined interfaces for Ising lattices, allowing also the estimation of line tensions of three-phase contact lines, when the interfaces meet walls (where "surface fields" may act). A generalization to off-lattice systems is described as well. The second method is based on the sampling of the order parameter distribution of the system throughout the two-phase coexistence region of the model. Both the interface free energies of flat interfaces and of (spherical or cylindrical) droplets (or bubbles) can be estimated, including also systems with walls, where sphere-cap shaped wall-attached droplets occur. The curvature-dependence of the interfacial free energy is discussed, and estimates for the line tensions are compared to results from the thermodynamic integration method. Basic limitations of all these methods are critically discussed, and an outlook on other approaches is given

Elevated expression of cyclooxygenase-2 is a negative prognostic factor for overall survival in intrahepatic cholangiocarcinoma

The production of prostaglandins is regulated by cyclooxygenases (COXs), which also have a role in tumour development and progression in various human malignancies, including cholangiocarcinoma. Limited information is available of the correlation of COX-2 protein expression and prognosis in intrahepatic cholangiocarcinoma (ICC). The aim of the present study was to determine the clinical significance of COX-2 expression in ICC. In addition the correlation of COX-2 expression and apoptosis/proliferation was analysed. COX-2 expression was determined immunohistochemically in 62 resected ICCs. Proliferation was assessed using Ki67-immunohistochemistry, and apoptosis was measured with the TdT-mediated dUTP nick-end-labelling technique. COX-2 was identified as an independent prognostic factor (P = 0.028) in resected ICC by survival analysis. High levels of COX-2 expression were found to be associated both with reduced apoptosis and increased proliferation of tumour cells. This study demonstrates the independent prognostic value of the COX-2 expression in resected ICC, thus, offering a potential additional adjuvant therapeutic approach with COX-2 inhibitors

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns