4,533 research outputs found
Thermochromic display materials for use under wide variations in ambient illumination levels Final report
Inorganic thermochromatic material synthesis and utilization in display device
Thermodynamics of nano-spheres encapsulated in virus capsids
We investigate the thermodynamics of complexation of functionalized charged
nano-spheres with viral proteins. The physics of this problem is governed by
electrostatic interaction between the proteins and the nano-sphere cores
(screened by salt ions), but also by configurational degrees of freedom of the
charged protein N-tails. We approach the problem by constructing an appropriate
complexation free energy functional. On the basis of both numerical and
analytical studies of this functional we construct the phase diagram for the
assembly which contains the information on the assembled structures that appear
in the thermodynamical equilibrium, depending on the size and surface charge
density of the nano-sphere cores. We show that both the nano-sphere core charge
as well as its radius determine the size of the capsid that forms around the
core.Comment: Submitte
Density waves theory of the capsid structure of small icosahedral viruses
We apply Landau theory of crystallization to explain and to classify the
capsid structures of small viruses with spherical topology and icosahedral
symmetry. We develop an explicit method which predicts the positions of centers
of mass for the proteins constituting viral capsid shell. Corresponding density
distribution function which generates the positions has universal form without
any fitting parameter. The theory describes in a uniform way both the
structures satisfying the well-known Caspar and Klug geometrical model for
capsid construction and those violating it. The quasiequivalence of protein
environments in viral capsid and peculiarities of the assembly thermodynamics
are also discussed.Comment: 8 pages, 3 figur
Notorious places: image, reputation, stigma: the role of newspapers in area reputations for social housing estates
This paper reviews work in several disciplines to distinguish between image, reputation and stigma. It also shows that there has been little research on the process by which area reputations are established and sustained through transmission processes. This paper reports on research into the portrayal of two social housing estates in the printed media over an extended period of time (14 years). It was found that negative and mixed coverage of the estates dominated, with the amount of positive coverage being very small. By examining the way in which dominant themes were used by newspapers in respect of each estate, questions are raised about the mode of operation of the press and the communities' collective right to challenge this. By identifying the way regeneration stories are covered and the nature of the content of positive stories, lessons are drawn for programmes of area transformation. The need for social regeneration activities is identified as an important ingredient for changing deprived-area reputations
Diverse hepatitis C virus glycoproteins mediate viral infection in a CD81-dependent manner
We recently reported that retroviral pseudotypes bearing the hepatitis C virus (HCV) strain H and Con1 glycoproteins, genotype 1a and 1b, respectively, require CD81 as a coreceptor for virus-cell entry and infection. Soluble truncated E2 cloned from a number of diverse HCV genotypes fail to interact with CD81, suggesting that viruses of diverse origin may utilize different receptors and display altered cell tropism. We have used the pseudotyping system to study the tropism of viruses bearing diverse HCV glycoproteins. Viruses bearing these glycoproteins showed a 150-fold range in infectivity for hepatoma cells and failed to infect lymphoid cells. The level of glycoprotein incorporation into particles varied considerably between strains, generally reflecting the E2 expression level within transfected cells. However, differences in glycoprotein incorporation were not associated with virus infectivity, suggesting that infectivity is not limited by the absolute level of glycoprotein. All HCV pseudotypes failed to infect HepG2 cells and yet infected the same cells after transduction to express human CD81, confirming the critical role of CD81 in HCV infection. Interestingly, these HCV pseudotypes differed in their ability to infect HepG2 cells expressing a panel of CD81 variants, suggesting subtle differences in the interaction of CD81 residues with diverse viral glycoproteins. Our current model of HCV infection suggests that CD81, together with additional unknown liver specific receptor(s), mediate the virus-cell entry process
Kinetics of viral self-assembly: the role of ss RNA antenna
A big class of viruses self-assemble from a large number of identical capsid
proteins with long flexible N-terminal tails and ss RNA. We study the role of
the strong Coulomb interaction of positive N-terminal tails with ss RNA in the
kinetics of the in vitro virus self-assembly. Capsid proteins stick to
unassembled chain of ss RNA (which we call "antenna") and slide on it towards
the assembly site. We show that at excess of capsid proteins such
one-dimensional diffusion accelerates self-assembly more than ten times. On the
other hand at excess of ss RNA, antenna slows self-assembly down. Several
experiments are proposed to verify the role of ss RNA antenna.Comment: 4 pages, 3 figures, several experiments are proposed, a new idea of
experiment is adde
Relative Roles of TGF-β and IGFBP-5 in Idiopathic Pulmonary Fibrosis
Although most evident in the skin, the process of scarring, or fibrosis, occurs in all major organs because of impaired epithelial self-renewal. No current therapy exists for Idiopathic pulmonary fibrosis. The major profibrotic factor is TGF-β1 and developing inhibitors is an area of active research. Recently, IGFBP-5 has also been identified as a profibrotic factor, and studies suggest that, while both TGF-β1 and IGFBP-5 activate mesenchymal cells to increase collagen and fibronectin production, their effects on epithelial cells are distinct. TGF-β1 induces cell death and/or EMT in the epithelial cells, exacerbating the disruption of tissue architecture. In contrast, IGFBP-5 induces epithelial cell spreading over collagen or fibronectin matrices, increases secretion of laminin, the epithelial basement membrane, and enhances the survival of epithelial cells in nutrient-poor conditions, as exists in scar tissue. Thus, IGFBP-5 may enhance repair and may be an important target for antifibrotic therapies
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