262 research outputs found

    Size-Dependent Lattice Structure and Confinement Properties in CsPbI₃ Perovskite Nanocrystals: Negative Surface Energy for Stabilization

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    CsPbI₃ nanocrystals with narrow size distributions were prepared to study the size-dependent properties. The nanocrystals adopt the perovskite (over the nonperovskite orthorhombic) structure with improved stability over thin-film materials. Among the perovskite phases (cubic α, tetragonal β, and orthorhombic γ), the samples are characterized by the γ phase, rather than α, but may have a size-dependent average tilting between adjacent octahedra. Size-dependent lattice constants systematically vary 3% across the size range, with unit cell volume increasing linearly with the inverse of size to 2.1% for the smallest size. We estimate the surface energy to be from −3.0 to −5.1 eV nm⁻² for ligated CsPbI₃ nanocrystals. Moreover, the size-dependent bandgap is best described using a nonparabolic intermediate confinement model. We experimentally determine the bulk bandgap, effective mass, and exciton binding energy, concluding with variations from the bulk α-phase values. This provides a robust route to understanding γ-phase properties of CsPbI₃

    An Unified Approach To Pseudo Scalar Meson Photoproductions Off Nucleons In The Quark Model

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    An unified approach to the pseudo scalar meson (π,η\pi, \eta, and KK) photoproduction off nucleons are presented. It begins with the low energy QCD Lagrangian, and the resonances in the s- and u- channels are treated in the framework of the quark model The duality hypothesis is imposed to limit the number of the t-channel exchanges. The CGLN amplitudes for each reaction are evaluated, which include both proton and neutron targets. The important role by the S-wave resonances in the second resonance region is discussed, it is particularly important for the K,ηK, \eta and η\eta^\prime photoproductions.Comment: 31 pages in Latex fil

    Quantum correlations and synchronization measures

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    The phenomenon of spontaneous synchronization is universal and only recently advances have been made in the quantum domain. Being synchronization a kind of temporal correlation among systems, it is interesting to understand its connection with other measures of quantum correlations. We review here what is known in the field, putting emphasis on measures and indicators of synchronization which have been proposed in the literature, and comparing their validity for different dynamical systems, highlighting when they give similar insights and when they seem to fail.Comment: book chapter, 18 pages, 7 figures, Fanchini F., Soares Pinto D., Adesso G. (eds) Lectures on General Quantum Correlations and their Applications. Quantum Science and Technology. Springer (2017

    The effects of lead time and visual aids in TTO valuation: a study of the EQ-VT framework

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    __Abstract__ __Background__ The effect of lead time in time trade-off (TTO) valuation is not well understood. The purpose of this study was to investigate the effects on health-state valuation of the length of lead time and the way the lead-time TTO task is displayed visually. __Methods__ Using two general population samples, we compared three lead-time TTO variants: 10 years of lead time in full health preceding 5 years of unhealthy time (standard); 5 years of lead time preceding 5 years of unhealthy time (experimental); and 10 years of lead time and 5 years of unhealthy time, presented with a visual aid to highlight the point where the lead time ends (experimental). Participants were randomized to receive one of the lead-time variants, as administered by a computer software program. __Results__ Health-state values generated by TTO valuation tasks using a longer lead time were slightly lower than those generated by tasks using a shorter lead time. When lead time and unhealthy time were presented with visual aids highlighting the difference between the lead time and unhealthy time, respondents spent more time considering health states with a value close to 0. __Conclusions__ Different lead-time time trade-off variants should be carefully studied in order to achieve the best measurement of health-state values using this new method

    Direct-acting antiviral agents for liver transplant recipients with recurrent genotype 1 hepatitis C virus infection: Systematic review and meta-analysis

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    Background: Comprehensive evaluation of safety and efficacy of different combina‐ tions of direct‐acting antivirals (DAAs) in liver transplant recipients with genotype 1 (GT1) hepatitis C virus (HCV) recurrence remains limited. Therefore, we performed this systematic review and meta‐analysis in order to evaluate the clinical outcome of DAA treatment in liver transplant patients with HCV GT1 recurrence. Methods: Studies were included if they contained information of 12 weeks sustained virologic response (SVR12) after DAA treatment completion as well as treatment re‐ lated complications for liver transplant recipients with GT1 HCV recurrence. Results: We identified 16 studies comprising 885 patients. The overall pooled esti‐ mate proportion of SVR12 was 93% (95% confidence interval (CI): 0.89, 0.96), with moderate heterogeneity observed (τ 2 = 0.01, P < 0.01, I 2 =75%). High tolerability was observed in liver transplant recipients reflected by serious adverse events (sAEs) with pooled estimate proportion of 4% (95% CI: 0.01, 0.07; τ2 = 0.02, P < 0.01, I 2 = 81%). For subgroup analysis, a total of five different DAA regimens were applied for treating these patients. Sofosbuvir/Ledipasvir (SOF/LDV) led the highest pooled estimate SVR12 proportion, followed by Paritaprevir/Ritonavir/Ombitasivir/Dasabuvir (PrOD), Daclatasvir (DCV)/Simeprevir (SMV) ± Ribavirin (RBV), and SOF/SMV ± RBV, Asunaprevir (ASV)/DCV. There was a tendency for favoring a higher pooled SVR12 proportion in patients with METAVIR Stage F0‐F2 of 97% (95% CI: 0.93, 0.99) com‐ pared to 85% (95% CI: 0.79, 0.90) for stage F3‐F4 (P < 0.01). There was no significant difference between LT recipients treated with or without RBV (P = 0.23). Conclusions: Direct‐acting antiviral treatment is highly effective and well‐tolerated in liver transplant recipients with recurrent GT1 HCV infection

    Intracellular β\u3csub\u3e1\u3c/sub\u3e-Adrenergic Receptors and Organic Cation Transporter 3 Mediate Phospholamban Phosphorylation to Enhance Cardiac Contractility

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    Rationale: β1ARs (β1-adrenoceptors) exist at intracellular membranes and OCT3 (organic cation transporter 3) mediates norepinephrine entry into cardiomyocytes. However, the functional role of intracellular β1AR in cardiac contractility remains to be elucidated. Objective: Test localization and function of intracellular β1AR on cardiac contractility. Methods and Results: Membrane fractionation, super-resolution imaging, proximity ligation, coimmunoprecipitation, and single-molecule pull-down demonstrated a pool of β1ARs in mouse hearts that were associated with sarco/endoplasmic reticulum Ca2+-ATPase at the sarcoplasmic reticulum (SR). Local PKA (protein kinase A) activation was measured using a PKA biosensor targeted at either the plasma membrane (PM) or SR. Compared with wild-type, myocytes lacking OCT3 (OCT3-KO [OCT3 knockout]) responded identically to the membrane-permeant βAR agonist isoproterenol in PKA activation at both PM and SR. The same was true at the PM for membrane-impermeant norepinephrine, but the SR response to norepinephrine was suppressed in OCT3-KO myocytes. This differential effect was recapitulated in phosphorylation of the SR-pump regulator phospholamban. Similarly, OCT3-KO selectively suppressed calcium transients and contraction responses to norepinephrine but not isoproterenol. Furthermore, sotalol, a membrane-impermeant βAR-blocker, suppressed isoproterenol-induced PKA activation at the PM but permitted PKA activation at the SR, phospholamban phosphorylation, and contractility. Moreover, pretreatment with sotalol in OCT3-KO myocytes prevented norepinephrine-induced PKA activation at both PM and the SR and contractility. Conclusions: Functional β1ARs exists at the SR and is critical for PKA-mediated phosphorylation of phospholamban and cardiac contractility upon catecholamine stimulation. Activation of these intracellular β1ARs requires catecholamine transport via OCT3

    Robust Detection and Genotyping of Single Feature Polymorphisms from Gene Expression Data

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    It is well known that Affymetrix microarrays are widely used to predict genome-wide gene expression and genome-wide genetic polymorphisms from RNA and genomic DNA hybridization experiments, respectively. It has recently been proposed to integrate the two predictions by use of RNA microarray data only. Although the ability to detect single feature polymorphisms (SFPs) from RNA microarray data has many practical implications for genome study in both sequenced and unsequenced species, it raises enormous challenges for statistical modelling and analysis of microarray gene expression data for this objective. Several methods are proposed to predict SFPs from the gene expression profile. However, their performance is highly vulnerable to differential expression of genes. The SFPs thus predicted are eventually a reflection of differentially expressed genes rather than genuine sequence polymorphisms. To address the problem, we developed a novel statistical method to separate the binding affinity between a transcript and its targeting probe and the parameter measuring transcript abundance from perfect-match hybridization values of Affymetrix gene expression data. We implemented a Bayesian approach to detect SFPs and to genotype a segregating population at the detected SFPs. Based on analysis of three Affymetrix microarray datasets, we demonstrated that the present method confers a significantly improved robustness and accuracy in detecting the SFPs that carry genuine sequence polymorphisms when compared to its rivals in the literature. The method developed in this paper will provide experimental genomicists with advanced analytical tools for appropriate and efficient analysis of their microarray experiments and biostatisticians with insightful interpretation of Affymetrix microarray data
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