7,787 research outputs found
Clumpy Structures within the Turbulent Primordial Cloud
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 , which conflicts with
recent observations of extremely metal-poor stars suggesting a lower mass scale
of around . 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 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 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
<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°â60°) to a postoperative mean of 16° (range, 0°â30°). 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
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
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
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 100 meV and 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
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
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
<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
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Synthetic control of living cells by intracellular polymerization
An emerging cellular engineering method creates synthetic polymer matrices inside cells. By contrast with classical genetic, enzymatic, or radioactive techniques, this materials-based approach introduces non-natural polymers inside cells, thus modifying cellular states and functionalities. Here, we cover various materials and chemistries that have been exploited to create intracellular polymer matrices. In addition, we discuss emergent cellular properties due to the intracellular polymerization, including nonreplicating but active metabolism, maintenance of membrane integrity, and resistance to environmental stressors. We also discuss past work and future opportunities for developing and applying synthetic cells that contain intracellular polymers. The materials-based approach will usher in new applications of synthetic cells for broad biotechnological applications
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