3,412 research outputs found

    Thermochromic display materials for use under wide variations in ambient illumination levels Final report

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    Inorganic thermochromatic material synthesis and utilization in display device

    Thermodynamics of nano-spheres encapsulated in virus capsids

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    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

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    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

    Diverse hepatitis C virus glycoproteins mediate viral infection in a CD81-dependent manner

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    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

    Remarkably robust and correlated coherence and antiferromagnetism in (Ce1−x_{1-x}Lax_x)Cu2_2Ge2_2

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    We present magnetic susceptibility, resistivity, specific heat, and thermoelectric power measurements on (Ce1−x_{1-x}Lax_x)Cu2_2Ge2_2 single crystals (0 ≤x≤\leq x\leq 1). With La substitution, the antiferromagnetic temperature TNT_N is suppressed in an almost linear fashion and moves below 0.36 K, the base temperature of our measurements for x>x> 0.8. Surprisingly, in addition to robust antiferromagnetism, the system also shows low temperature coherent scattering below TcohT_{coh} up to ∼\sim 0.9 of La, indicating a small percolation limit ∼\sim 9%\% of Ce that separates a coherent regime from a single-ion Kondo impurity regime. TcohT_{coh} as a function of magnetic field was found to have different behavior for xx 0.9. Remarkably, (Tcoh)2(T_{coh})^2 at HH = 0 was found to be linearly proportional to TNT_N. The jump in the magnetic specific heat δCm\delta C_{m} at TNT_N as a function of TK/TNT_K/T_N for (Ce1−x_{1-x}Lax_x)Cu2_2Ge2_2 follows the theoretical prediction based on the molecular field calculation for the SS = 1/2 resonant level model

    Notorious places: image, reputation, stigma: the role of newspapers in area reputations for social housing estates

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    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
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