7,471 research outputs found

    Clumpy Structures within the Turbulent Primordial Cloud

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    The primordial clouds in the mini-halos hatch the first generation stars of the universe, which play a crucial role in cosmic evolution. In this paper, we investigate how the turbulence impacts the structure of primordial star-forming cloud. Previous cosmological simulations of the first star formation predicted a typical mass of around 100 M⊙\mathrm{ 100 \, M_\odot}, which conflicts with recent observations of extremely metal-poor stars suggesting a lower mass scale of around 25 M⊙\mathrm{25 \, M_\odot}. The discrepancy may arise from unresolved turbulence in the star-forming cloud, driven by primordial gas accretion during mini-halo formation in the previous simulation. To quantitatively examine the turbulence effect on the primordial cloud formation, we employ the adaptive mesh refinement code Enzo\mathtt{Enzo} to model the gas cloud with primordial composition, including artificial-driven turbulence on the cloud scale and relevant gas physics. This artificial-driven turbulence utilizes a stochastic forcing model to mimic the unresolved turbulence inside mini-halos. Our results show that turbulence with high Mach number and compressional mode effectively fragments the cloud into several clumps, each with dense cores of 22.7−174.9 M⊙\mathrm{22.7 - 174.9 \, M_\odot} that undergo Jeans instability to form stars. Fragmentation caused by intense and compressive turbulence prevents the runaway collapse of the cloud. The self-bound clumps with smaller masses in turbulent primordial cloud suggest a possible pathway to decrease the theoretical mass scale of first stars, further reconciling the mass discrepancy between simulations and observations.Comment: All comments are welcome. Submitted to MNRAS. (13 pages, 10 figures, 2 tables

    Extensor-tendons reconstruction using autogenous palmaris longus tendon grafting for rheumatoid arthritis patients

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    <p>Abstract</p> <p>Background</p> <p>The purpose of the study is to retrospectively review the clinical outcome of our study population of middle-aged RA patients who had suffered extensor-tendon rupture. We reported the outcome of autogenous palmaris tendon grafting of multiple extensor tendons at wrist level in 14 middle-aged rheumatoid patients.</p> <p>Methods</p> <p>Between Feb. 2000 to Feb. 2004, thirty-six ruptured wrist level extensor tendons were reconstructed in fourteen rheumatoid patients (11 women and three men) using autogenous palmaris longus tendon as a free interposition graft. In each case, the evaluation was based on both subjective and objective criteria, including the range of MCP joint flexion after surgery, the extension lag at the metacarpophalangeal joint before and after surgery, and the ability of the patient to work.</p> <p>Results and Discussion</p> <p>The average of follow-up was 54.1 months (range, 40 to 72 months). The average range of MCP joint flexion after reconstruction was 66°. The extension lag at the metacarpophalangeal joint significantly improved from a preoperative mean of 38° (range, 25°–60°) to a postoperative mean of 16° (range, 0°–30°). Subjectively all patients were satisfied with the clinical results, and achieved a return to their level of ability before tendon rupture. We found good functional results in our series of interposition grafting using palmaris longus to reconstruct extensor tendon defects in the rheumatoid patients.</p> <p>Conclusion</p> <p>Reconstruction for multiple tendon ruptures is a salvage procedure that is often associated with extensor lag and impairment of overall function. Early aggressive treatment of extensor tendon reconstruction using autogenous palmaris longus tendon as a free interposition graft in the rheumatoid wrist is another viable option to achieve good clinical functional result.</p

    Automating the audit of electronic invoices with a soft robot

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    Taiwan's Chi Mei Medical Center has completed four challenges mentioned in published robotic process automation (RPA) studies including automating a dynamic process, designing feasible human-robot collaboration, incorporating other emerging technologies, and bringing positive business impacts. Its executives called a committee to implement the electronic invoicing. This implementation includes the creation of a software robot to download automatically cloud electronic invoice (E-invoice) data from Taiwan's E-invoice platform and detect the inconsistency between them and on-premise data. This bot operates when internal auditors are off their office. They satisfied this software robot since the remaining work is only verifying the resulting inconsistency. The Chi Mei Medical Center measured the time and costs before and after adopting software robots to audit E-invoice; consequently, it welcomed more bots automating other business processes. In conclusion, integrating a software robot with other emerging technologies mitigates the possible errors provided by this bot. A good human-robot collaboration relies on the consideration of human perspective in choosing RPA tasks. Free bot creators are sufficient to verify that automating a business process using a bot is a reasonable investment.Comment: 11 pages, 6 figures, 1 tabl

    Second generation Dirac cones and inversion symmetry breaking induced gaps in graphene/hexagonal boron nitride

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    Graphene/h-BN has emerged as a model van der Waals heterostructure, and the band structure engineering by the superlattice potential has led to various novel quantum phenomena including the self-similar Hofstadter butterfly states. Although newly generated second generation Dirac cones (SDCs) are believed to be crucial for understanding such intriguing phenomena, so far fundamental knowledge of SDCs in such heterostructure, e.g. locations and dispersion of SDCs, the effect of inversion symmetry breaking on the gap opening, still remains highly debated due to the lack of direct experimental results. Here we report first direct experimental results on the dispersion of SDCs in 0∘^\circ aligned graphene/h-BN heterostructure using angle-resolved photoemission spectroscopy. Our data reveal unambiguously SDCs at the corners of the superlattice Brillouin zone, and at only one of the two superlattice valleys. Moreover, gaps of ≈\approx 100 meV and ≈\approx 160 meV are observed at the SDCs and the original graphene Dirac cone respectively. Our work highlights the important role of a strong inversion symmetry breaking perturbation potential in the physics of graphene/h-BN, and fills critical knowledge gaps in the band structure engineering of Dirac fermions by a superlattice potential.Comment: Nature Physics 2016, In press, Supplementary Information include

    Functional annotation of proteomic data from chicken heterophils and macrophages induced by carbon nanotube exposure

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    With the expanding applications of carbon nanotubes (CNT) in biomedicine and agriculture, questions about the toxicity and biocompatibility of CNT in humans and domestic animals are becoming matters of serious concern. This study used proteomic methods to profile gene expression in chicken macrophages and heterophils in response to CNT exposure. Two-dimensional gel electrophoresis identified 12 proteins in macrophages and 15 in heterophils, with differential expression patterns in response to CNT co-incubation (0, 1, 10, and 100 ”g/mL of CNT for 6 h) (p < 0.05). Gene ontology analysis showed that most of the differentially expressed proteins are associated with protein interactions, cellular metabolic processes, and cell mobility, suggesting activation of innate immune functions. Western blot analysis with heat shock protein 70, high mobility group protein, and peptidylprolyl isomerase A confirmed the alterations of the profiled proteins. The functional annotations were further confirmed by effective cell migration, promoted interleukin-1ÎČ secretion, and more cell death in both macrophages and heterophils exposed to CNT (p < 0.05). In conclusion, results of this study suggest that CNT exposure affects protein expression, leading to activation of macrophages and heterophils, resulting in altered cytoskeleton remodeling, cell migration, and cytokine production, and thereby mediates tissue immune responses

    Prevalence of latent tuberculosis infection in BCG-vaccinated healthcare workers by using an interferon-gamma release assay and the tuberculin skin test in an intermediate tuberculosis burden country

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    BackgroundThe risk of healthcare workers (HCWs) acquiring tuberculosis (TB) infection is high. We determined the prevalence of latent TB infection (LTBI) in HCWs with a high Bacille Calmette-Guérin (BCG) vaccine coverage in an intermediate TB burden country by using an interferon-gamma release assay [QuantiFERON-TB Gold (QFT-G)] and by using the tuberculin skin test (TST). Risk factors associated with a positive test were determined.MethodsThis prospective cross-sectional study enrolled HCWs from a medical center in Taiwan. Participants were grouped into workers without exposure (Group 1) and workers who self-reported a history of TB exposure (Group 2). All participants completed a questionnaire to collect demographic information and risk factors for acquiring TB. The QFT-G test and the TST were administered and risk factors for a positive test were analyzed.ResultsWe recruited 193 HCWs [149 (77.2%) female workers] with a mean age of 35.6 years. All were BCG-vaccinated. The prevalence of LTBI was 88.8% (based on the TST) and 14.5% (based on the QFT-G test). There was no difference between HCWs with and without known exposure to TB. Agreement between the tests was poor (i.e., the kappa value was less than 0.05). Multivariable logistic regression showed that only the QFT-G test was associated with age (35 years or greater) (adjusted OR, 2.53; p = 0.03).ConclusionBy using the QFT-G test or TST, this study found a similar prevalence of LTBI in HCWs with and without known exposure to TB. This suggests that in intermediate TB burden countries exposure to TB may occur within the hospital and within the community. Compared to the TST, the QFT-G test was correlated better with age, which is a known risk factor for latent TB infection

    Functional analysis of novel SNPs and mutations in human and mouse genomes

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    <p>Abstract</p> <p>Background</p> <p>With the flood of information generated by the new generation of sequencing technologies, more efficient bioinformatics tools are needed for in-depth impact analysis of novel genomic variations. FANS (Functional Analysis of Novel SNPs) was developed to streamline comprehensive but tedious functional analysis steps into a few clicks and to offer a carefully designed presentation of results so researchers can focus more on thinking instead of typing and calculating.</p> <p>Results</p> <p>FANS <url>http://fans.ngc.sinica.edu.tw/</url> harnesses the power of public information databases and powerful tools from six well established websites to enhance the efficiency of analysis of novel variations. FANS can process any point change in any coding region or GT-AG splice site to provide a clear picture of the disease risk of a prioritized variation by classifying splicing and functional alterations into one of nine risk subtypes with five risk levels.</p> <p>Conclusion</p> <p>FANS significantly simplifies the analysis operations to a four-step procedure while still covering all major areas of interest to researchers. FANS offers a convenient way to prioritize the variations and select the ones with most functional impact for validation. Additionally, the program offers a distinct improvement in efficiency over manual operations in our benchmark test.</p

    Prevalence of latent tuberculosis infection in persons with and without human immunodeficiency virus infection using two interferon-gamma release assays and tuberculin skin test in a low human immunodeficiency virus prevalence, intermediate tuberculosis-burden country

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    BackgroundThe risk of tuberculosis (TB) is higher in human immunodeficiency virus (HIV)-infected patients and intravenous drug users (IDUs). We determined the prevalence and risk factors of latent TB infection (LTBI) in individuals with or without HIV infection, including IDUs, in a country with a low HIV prevalence, an intermediate TB burden, and a high Bacillus Calmette-GuĂ©rin (BCG) vaccine coverage using two interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST).MethodsFor this prospective, cross-sectional study, HIV-infected and -uninfected patients from a regional hospital and medical center in Taiwan were enrolled. Results of the two IGRAs [QuantiFERON-TB Gold (QFT-G) and QuantiFERON-TB Gold In-Tube (QFT-GIT)] and the TST were compared. Risk factors for positivity were analyzed.ResultsWe recruited 233 patients [198 (85%) men; mean age, 39.4 years]. Most patients (74%) were BCG vaccinated. The prevalence of LTBI was estimated to be 22.8% by TST, 15.9% by QFT-G, and 20.6% by QFT-GIT. HIV-infected individuals had fewer positive QFT-GIT [7.0% vs. 28.6%, p < 0.001, adjusted odds ratio (aOR) = 0.28, p = 0.05] and TST results, and more indeterminate QFT-G responses (9.3% vs. 0.7%, p = 0.002). Concordance between IGRAs and TST was very poor in HIV-infected patients (Îș < 0.05). Independent risk factors for IGRA positivity were increasing age (QFT-G: aOR = 1.98, p = 0.03; QFT-GIT: aOR = 2.00, p = 0.01) and IDUs (aOR = 4.33, p = 0.05 by QFT-G).ConclusionHIV-infected persons had a significantly lower response to both IGRAs and TST. High discordance was found between the two generations of IGRAs and between IGRAs and TST. Increasing age, a known risk factor for LTBI, was significantly associated with IGRAs, but not with TST
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