45 research outputs found

    Correction to “Crystal Structures, Optical Properties, and Effective Mass Tensors of CH<sub>3</sub>NH<sub>3</sub>PbX<sub>3</sub> (X = I and Br) Phases Predicted from HSE06”

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    Correction to “Crystal Structures, Optical Properties, and Effective Mass Tensors of CH<sub>3</sub>NH<sub>3</sub>PbX<sub>3</sub> (X = I and Br) Phases Predicted from HSE06

    Crystal Structures, Optical Properties, and Effective Mass Tensors of CH<sub>3</sub>NH<sub>3</sub>PbX<sub>3</sub> (X = I and Br) Phases Predicted from HSE06

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    The crystal structures are successfully established for tetragonal and orthorhombic CH<sub>3</sub>NH<sub>3</sub>PbX<sub>3</sub> (X = I and Br). The equilibrium lattice parameters are computed by the DFT+D2 method, and the results are compared to experimental values. The band dispersions and electronic densities of states are calculated by HSE06, showing that their band gaps are in the range from 1.63 to 2.3 eV. Although the calculated dielectric functions of MAPbX<sub>3</sub> compounds are similar to other semiconductors, the absorption spectra of their bulk crystals are drifted away from visible light spectrum. The effective mass tensors of holes and electrons are also evaluated in three principal directions at the Γ point. The anisotropies in the effective masses of the hole and electron are illustrated for two orthorhombic phases

    Correction to “Crystal Structures, Optical Properties, and Effective Mass Tensors of CH<sub>3</sub>NH<sub>3</sub>PbX<sub>3</sub> (X = I and Br) Phases Predicted from HSE06”

    No full text
    Correction to “Crystal Structures, Optical Properties, and Effective Mass Tensors of CH<sub>3</sub>NH<sub>3</sub>PbX<sub>3</sub> (X = I and Br) Phases Predicted from HSE06

    Transport Properties and High Thermopower of SnSe<sub>2</sub>: A Full Ab-Initio Investigation

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    Motivated by the observation that many known layered chalcogenides show promising thermoelectric properties, we investigate the similar properties of SnSe<sub>2</sub> by solving the Boltzmann transport equation for both lattice and electron. A self-consistent single parabolic band model (SPB) is employed to compute the electron relaxation time rigorously. The obtained intrinsic lattice thermal conductivities in <i>a</i> and <i>c</i> directions are 6.78 and 0.79 W/m·K at 300 K. The results show that acoustic phonon branches play the dominant role in heat transport. Thermoelectric properties of n-type SnSe<sub>2</sub> are found to be significantly better than those of p-type doping for temperatures between 200 and 800 K and carrier concentrations between 10<sup>17</sup> and 10<sup>20</sup> cm<sup>–3</sup>. At <i>n</i> = 10<sup>20</sup> cm<sup>–3</sup> and 300 K, we find σ<sub><i>a</i></sub> = 4.97 × 10<sup>5</sup> Ω<sup>–1</sup>·m<sup>–1</sup> and σ<sub><i>c</i></sub> = 3.39 × 10<sup>4</sup> Ω<sup>–1</sup>·m<sup>–1</sup> and the ratio σ<sub><i>a</i></sub>/σ<sub><i>c</i></sub> = 14.67 for n-type SnSe<sub>2</sub>. Both electrical and lattice thermal conductivities show a strong anisotropic feature. A high thermoelectric figure of merit is revealed in n-type SnSe<sub>2</sub> (ZT<sub><i>a</i></sub> = 2.95 and ZT<sub><i>c</i></sub> = 0.68 at <i>n</i> = 10<sup>20</sup> cm<sup>–3</sup> and 800 K). The large ZT value indicates that SnSe<sub>2</sub> is a promising candidate for thermoelectric applications

    A meta-GGA Made Free of the Order of Limits Anomaly

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    We have improved the revised Tao–Perdew–Staroverov–Scuseria (revTPSS) meta-generalized gradient approximation (GGA) in order to remove the order of limits anomaly in its exchange energy. The revTPSS meta-GGA recovers the second-order gradient expansion for a wide range of densities and therefore provides excellent atomization energies and lattice constants. For other properties of materials, however, even the revTPSS does not give the desired accuracy. The revTPSS does not perform as well as expected for the energy differences between different geometries for the same molecular formula and for the related nonbarrier height chemical reaction energies. The same order of limits problem might lead to inaccurate energy differences between different crystal structures and to inaccurate cohesive energies of insulating solids. Here we show a possible way to remove the order of limits anomaly with a weighted difference of the revTPSS exchange between the slowly varying and iso-orbitals (one- or two-electron) limits. We show that the new regularized (regTPSS) gives atomization energies comparable to revTPSS and preserves the accurate lattice constants as well. For other properties, the regTPSS gives at least the same performance as the revTPSS or TPSS meta-GGAs

    Involvement of Receptor Tyrosine Kinase Tyro3 in Amyloidogenic APP Processing and β-Amyloid Deposition in Alzheimer's Disease Models

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    <div><p>Alzheimer's disease (AD) is the most common progressive neurodegenerative disease known to humankind. It is characterized by brain atrophy, extracellular amyloid plaques, and intracellular neurofibril tangles. β-amyloid cascade is considered the major causative player in AD. Up until now, the mechanisms underlying the process of Aβ generation and accumulation in the brain have not been well understood. Tyro3 receptor belongs to the TAM receptor subfamily of receptor protein tyrosine kinases (RPTKs). It is specifically expressed in the neurons of the neocortex and hippocampus. In this study, we established a cell model stably expressing APPswe mutants and producing Aβ. We found that overexpression of Tyro3 receptor in the cell model significantly decreased Aβ generation and also down-regulated the expression of β-site amyloid precursor protein cleaving enzyme (BACE1). However, the effects of Tyro3 were inhibited by its natural ligand, Gas6, in a concentration-dependent manner. In order to confirm the role of Tyro3 in the progression of AD development, we generated an AD transgenic mouse model accompanied by Tyro3 knockdown. We observed a significant increase in the number of amyloid plaques in the hippocampus in the mouse model. More plaque-associated clusters of astroglia were also detected. The present study may help researchers determine the role of Tyro3 receptor in the neuropathology of AD.</p> </div

    Data_Sheet_1_Chaperonin TRiC/CCT subunit CCT7 is involved in the replication of canine parvovirus in F81 cells.docx

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    Canine parvovirus (CPV) is one of the most common lethal viruses in canines. The virus disease is prevalent throughout the year, with high morbidity and mortality rate, causing serious harm to dogs and the dog industry. Previously, yeast two hybrid method was used to screen the protein chaperonin containing TCP-1 (CCT7) that interacts with VP2. However, the mechanism of interactions between CCT7 and VP2 on CPV replication remains unclear. In this study, we first verified the interaction between CCT7 and viral VP2 proteins using yeast one-to-one experiment and co-immunoprecipitation (CoIP) experiment. Laser confocal microscopy observation showed that CCT7 and VP2 were able to co-localize and were mostly localized in the cytoplasm. In addition, the study of VP2 truncated mutant found that the interaction region of VP2 with CCT7 was located between amino acids 231 and 320. Cycloheximide (CHX) chase experiments showed that CCT7 can improve the stability of VP2 protein. After further regulation of CCT7 expression in F81 cells, it was found that the expression level of VP2 protein was significantly reduced after knocking down CCT7 expression by RNA interference (RNAi) or HSF1A inhibitor, and increased after overexpressing host CCT7. The study reveals the role of VP2 interacting protein CCT7 in the replication process of CPV, which could provide a potential target for the prevention and control of CPV.</p

    Tyro3 knockdown has no effect on microglial activation in 5XFAD mouse brains.

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    <p>(A, B, C) Iba1 immunostaining in 5XFAD mouse brain slices (Scale bar = 200, 100, 50 μm, respectively). (D, E, F) Iba1 immunoreactive microglia in 5XFAD; T−/+ mouse brain slices (Scale bar = 200, 100, 50 μm, respectively). (G) Quantification of mean optical density (OD) of Iba1 staining showing no significant difference between 5XFAD controls and 5XFAD; T−/+ mouse brains. (H) Statistical analysis of ratio of area occupied by Iba1-ir cells to total area of image showing no significant change between 5XFAD controls and 5XFAD; T−/+ mouse brains (student's t-test).</p
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