A Strain-Driven Morphotropic Phase Boundary in BiFeO3 Zeches, R. J.; Rossell, M. D.; Zhang, J. X. ...
Science (American Association for the Advancement of Science),
11/2009, Volume:
326, Issue:
5955
Journal Article
Peer reviewed
Open access
Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. ...Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field–dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.
Constructing artificial helical structures through hierarchical self-assembly and exploring the underlying mechanism are important, and they help gain insight from the structures, processes, and ...functions from the biological helices and facilitate the development of material science and nanotechnology. Herein, the two enantiomers of chiral Au(I) complexes ( S )-1 and ( R )-1 were synthesized, and they exhibited impressive spontaneous hierarchical self-assembly transitions from vesicles to helical fibers. An impressive chirality inversion and amplification was accompanied by the assembly transition, as elucidated by the results of in situ and time-dependent circular dichroism spectroscopy and scanning electron microscope imaging. The two enantiomers could serve as ideal chiral templates to co-assemble with other achiral luminogens to efficiently induce the resulting co-assembly systems to show circularly polarized luminescence (CPL). Our work has provided a simple but efficient way to explore the sophisticated self-assembly process and presented a facile and effective strategy to fabricate architectures with CPL properties.
Anti-interferon- γ (IFN-γ) autoantibodies (anti-IFN-γ Abs) have been increasingly recognized as an important cause of disseminated nontuberculous mycobacterial (DNTM) infection, and identification of ...this immunodeficiency impacts clinical management. However, the protean disease manifestations and inaccessibility to diagnostic tests in clinical settings hamper its early diagnosis. Here, we sought to determine whether QuantiFERON-TB Gold In-tube (QFT-GIT), a commercialized IFN-γ release assay, could be used to screen for neutralizing anti-IFN-γ Abs among previously healthy adults with DNTM infection.
Non-HIV patients with DNTM infection were prospectively enrolled for the QFT-GIT assays. We measured their plasma concentration of anti-IFN-γ Abs and their neutralizing capacity through enzyme-linked immunosorbent assay and flow cytometry. We then analysed the correlation between QFT-GIT results and the presence of neutralizing anti-IFN-γ Abs among patients with and without previously recognized immunosuppression, respectively.
Irrespective of the autoantibody concentration or disease activity, all patients with neutralizing anti-IFN-γ Abs (100%, 30/30) had indeterminate QFT-GIT results because of extremely low or undetectable IFN-γ levels in the mitogen tubes. None of the four DNTM patients who were previously healthy and tested negative of anti-IFN-γ Abs had an indeterminate QFT-GIT result, and their IFN-γ levels in the mitogen tube were significantly higher than those of the patients with anti-IFN-γ Abs (8.28 IU/mL vs. 0.05 IU/mL, p 0.001).
An indeterminate QFT-GIT result because of undetectable or extremely low IFN-γ level in the mitogen tube suggests the presence of neutralizing anti-IFN-γ Abs in a previously healthy patient with DNTM infection.
Single-cell multiomics data continues to grow at an unprecedented pace. Although several methods have demonstrated promising results in integrating several data modalities from the same tissue, the ...complexity and scale of data compositions present in cell atlases still pose a challenge. Here, we present scJoint, a transfer learning method to integrate atlas-scale, heterogeneous collections of scRNA-seq and scATAC-seq data. scJoint leverages information from annotated scRNA-seq data in a semisupervised framework and uses a neural network to simultaneously train labeled and unlabeled data, allowing label transfer and joint visualization in an integrative framework. Using atlas data as well as multimodal datasets generated with ASAP-seq and CITE-seq, we demonstrate that scJoint is computationally efficient and consistently achieves substantially higher cell-type label accuracy than existing methods while providing meaningful joint visualizations. Thus, scJoint overcomes the heterogeneity of different data modalities to enable a more comprehensive understanding of cellular phenotypes.
Summary Background Transmission of the novel avian influenza A H7N9 virus seems to be predominantly between poultry and people. In the major Chinese cities of Shanghai, Hangzhou, Huzhou, and ...Nanjing—where most human cases of infection have occurred—live poultry markets (LPMs) were closed in April, 2013, soon after the initial outbreak, as a precautionary public health measure. Our objective was to quantify the effect of LPM closure in these cities on poultry-to-person transmission of avian influenza A H7N9 virus. Methods We obtained information about every laboratory-confirmed human case of avian influenza A H7N9 virus infection reported in the four cities by June 7, 2013, from a database built by the Chinese Center for Disease Control and Prevention. We used data for age, sex, location, residence type (rural or urban area), and dates of illness onset. We obtained information about LPMs from official sources. We constructed a statistical model to explain the patterns in incidence of cases reported in each city on the basis of the assumption of a constant force of infection before LPM closure, and a different constant force of infection after closure. We fitted the model with Markov chain Monte Carlo methods. Findings 85 human cases of avian influenza A H7N9 virus infection were reported in Shanghai, Hangzhou, Huzhou, and Nanjing by June 7, 2013, of which 60 were included in our main analysis. Closure of LPMs reduced the mean daily number of infections by 99% (95% credibility interval 93–100%) in Shanghai, by 99% (92–100%) in Hangzhou, by 97% (68–100%) in Huzhou, and by 97% (81–100%) in Nanjing. Because LPMs were the predominant source of exposure to avian influenza A H7N9 virus for confirmed cases in these cities, we estimated that the mean incubation period was 3·3 days (1·4–5·7). Interpretation LPM closures were effective in the control of human risk of avian influenza A H7N9 virus infection in the spring of 2013. In the short term, LPM closure should be rapidly implemented in areas where the virus is identified in live poultry or people. In the long term, evidence-based discussions and deliberations about the role of market rest days and central slaughtering of all live poultry should be renewed. Funding Ministry of Science and Technology, China; Research Fund for the Control of Infectious Disease; Hong Kong University Grants Committee; China–US Collaborative Program on Emerging and Re-emerging Infectious Diseases; Harvard Center for Communicable Disease Dynamics; and the US National Institutes of Health.
HER2 has a predictive value in gastric cancer. However, its association with prognosis remains uncertain. The aim of our study was to estimate the HER2-positive rate in Chinese gastric cancers, ...compare the classical fluorescence in situ hybridization (FISH) method with the novel bright-field dual color silver-enhanced in situ hybridization (DSISH) detection system, and evaluate the relationship between the HER2 status and prognosis.
Seven hundred and twenty-six resected gastric cancers separately from four clinical centers in China were examined for HER2 by immunohistochemistry (IHC), FISH, and DSISH.
The HER2-positive rate was 13%. The consistency between FISH and DSISH results was high (99%; κ = 0.958; P < 0.001). Tumor heterogeneity and polysomy were the main reasons for inconsistency. There was no significant difference in the 3-year overall survival (OS) between HER2-positive and -negative patients (P = 0.959). Multivariate analysis showed that HER2 was not an independent prognostic factor.
HER2 overexpression and amplification occur in a significant number of Chinese gastric cancer patients. Given the obvious advantages and high consistency with FISH, DSISH was superior for evaluating HER2 amplification in gastric cancer. HER2 was not a prognostic factor for gastric cancer in our study.
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