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SeongMin Jeong Xin Zhou Ekaterina B. Zhulina YongSeok Jho 《Israel journal of chemistry》2016,56(8):599-606
Grand canonical Monte Carlo (MC) simulations are performed to analyse conformations of projection domains in a neurofilament (NF) brush composed of three types of tails (L, M, and H) at different concentrations of added salt. The NF is modelled as a rigid, uniformly charged cylinder (backbone), surrounded by tethered, flexible polyampholytic chains with charge distributions and stoichiometry similar to those in natural NFs. We calculate the equilibrium trajectory for each projection; that is, the average distance of the amino acid residue from the surface of the backbone as a function of its ranking number. These trajectories demonstrate the tendency for projections to fold back and adopt loop-like conformations at moderate solution salinities. We also perform extended analysis of MC data to identify metastable states of the system, and demonstrate representative snapshots of tail conformations in major metastable states. 相似文献
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Highly ordered and vertically oriented TiO2 nanotube arrays with a length of 250 nm and a diameter of 70 nm were prepared by atomic layer deposition (ALD) coupled with anodic aluminum oxide (AAO) template. An ordered heterojunction (OHJ) polymer/inorganic hybrid solar cell was fabricated by successful infiltration of P3HT into the nanotube arrays. Structural features of the nanotube arrays enabling the interdigitated structure of the OHJ were discussed and the performance of the solar cell was characterized to be the power conversion efficiency of 0.50%. 相似文献
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P19 mouse embryonal carcinoma cells can be stimulated to differentiate into endodermal-like, mesodermal-like, and neuronal-like phenotypes in response to specific morphogens. At low concentrations, retinoic acid stimulates P19 embryonal cells to differentiate to cells displaying an endodermal phenotype, whereas at higher concentrations it stimulates differentiation to neuroectoderm. The Galpha12 and Galpha13 subunits of heterotrimeric G-proteins are expressed in the embryonal P19 cells and stimulated in response to retinoic acid as the cells differentiate to endodermal or neuroectodermal phenotypes. Suppression of the expression of either Galpha12 or Galpha13 by antisense RNA is shown to promote cell detachment from substratum and apoptosis. Expression of the constitutively active, mutant form of Galpha12 (Q229L), in contrast, stimulates loss of the embryonal phenotype. Expression of the constitutively active form of Galpha13 (Q226L) stimulates differentiation of the cells from embryonal to endodermal, in the absence of retinoic acid. Thus, both Galpha12 and Galpha13 are essential to stimulation of cell differentiation by retinoic acid. Deficiency of either Galpha12 or Galpha13 increases programmed cell death. 相似文献
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Yong-Hun Cho Jin Woo Bae Yoon-Hwan Cho Ju Wan Lim Minjeh Ahn Won-Sub Yoon Nak-Hyun Kwon Jae Young Jho Yung-Eun Sung 《International Journal of Hydrogen Energy》2010
In this work, a surface modified Nafion 212 membrane was fabricated by plasma etching in order to enhance the performance of a membrane electrode assembly (MEA) in a polymer electrolyte membrane fuel cell. Single-cell performance of MEA at 0.7 V was increased by about 19% with membrane that was etched for 10 min compared to that with untreated Nafion 212 membrane. The MEA with membrane etched for 20 min exhibited a current density of 1700 mA cm−2 at 0.35 V, which was 8% higher than that of MEA with untreated membrane (1580 mA cm−2). The performances of MEAs containing etched membranes were affected by complex factors such as the thickness and surface morphology of the membrane related to etching time. The structural changes and electrochemical properties of the MEAs with etched membranes were characterized by field emission scanning electron microscopy, Fourier transform-infrared spectrometry, electrochemical impedance spectroscopy, and cyclic voltammetry. 相似文献
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Jin Woo Bae Tae Uk Yang Gi Joon Nam Gun Joo Lee Byeong-Uk Nam Jae Young Jho 《Polymer Bulletin》2011,67(4):729-740
Ethylene vinylacetate (EVA) copolymer-based nanocomposites with maleic anhydride-grafted ethylene-vinylacetate (EVAgMA) and
organically modified clay (o-clay) were prepared in a twin screw extruder by following a two-step melt compounding method.
EVAgMA/o-clay masterbatches with various clay contents up to 50 wt% were examined, after which the masterbatch with the highest
clay content was melt compounded with EVA for the preparation of EVA/o-clay nanocomposites containing specific amounts of
clay. Further morphological dispersion of the clay particles by highly polar EVA and shearing was confirmed in the EVA/o-clay
nanocomposites by X-ray diffraction (XRD) and transmission electron microscopy (TEM). These morphologies led to increased
thermal properties in air as well as a considerable decrease in heat release rate (HRR). EVA/o-clay/MDH nanocomposites were
also prepared using a high clay-bearing masterbatch to confirm the synergistic flame retardancy of clay as a co-additive in
EVA/MDH composites. EVA/o-clay/MDH nanocomposites prepared by substituting o-clay for MDH showed significantly lower and wider
HRR during combustion compared to EVA/MDH composite. 相似文献
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Various methods such as stippling, hatching, or hedcut are being used to express the brightness of images as a tone. In this paper, as a new method of tonal depiction, we use the mathematical model used in biology for the purpose of expanding the area of non-photorealistic rendering. The model of reaction–diffusion, which is used to depict the skin patterns of diverse animals, has relatively recently been used as the technique of NPR. The biggest obstacle in processing this technique in real time is that it is very time-consuming process of the repeated calculation. In this contribution, we proposed how to build a mask creating similar results in order to gain instant results from the brightness of images. Mask is a two-dimensional table, which is beforehand calculated and used in digital halftoning, can process each pixel of pictures and produce the quickest result. Although the mask obtained as a result uses a uniform size repeatedly throughout the whole images, it has the merit of the repeated parts not being exposed because of the continuity of the connected parts. As the result, we compare the images through the masks made by both the existing method by repetition and the suggested method. 相似文献
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Summary
In the present work clay/polystyrene hybrids were prepared by emulsion polymerization, and subsequent coagulation technique.
Two different coagulants, magnesium sulfate and aluminum sulfate, were used in order to compare the coagulation efficiency,
and the final structure and dispersion-state were analyzed by X-ray diffraction method. Aluminum sulfate-water solution is
more effective in coagulation of polystyrene emulsion than magnesium sulfate-water solution. Small peaks near 2θ= 6° appear
in XRD diffraction patterns of all the hybrids. It is confirmed that these small XRD peaks are ascribed with the ordering
of silicate layers between which hydrated metal complex polycations are located with layers of water molecules.
Received: 22 December 2000/Revised version: 24 March 2001/Accepted: 27 March 2001 相似文献