2,545 research outputs found

    Delayed Wound Closure in Fibromodulin-Deficient Mice Is Associated with Increased TGF-β3 Signaling

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    Fibromodulin (FMOD), a small leucine-rich proteoglycan, mediates scarless fetal skin wound repair through, in part, transforming growth factor-Β (TGF-Β) modulation. Using an adult fmod-null (fmod -/-) mouse model, this study further elucidates the interplay between FMOD and TGF-Β expression during cutaneous repair and scar formation. Full-thickness skin wounds on fmod -/- and wild-type (WT) mice were closed primarily and analyzed. Histomorphometry revealed delayed dermal cell migration leading to delayed wound closure and significantly increased scar size in fmod -/- mice relative to WT, which was partially rescued by exogenous FMOD administration. In addition, fmod -/- wounds exhibited early elevation (within 24 hours post-wounding) of type I and type II TGF-Β receptors as well as unexpectedly high fibroblast expression of TGF-Β3, a molecule with reported antifibrotic and antimigratory effects. Consistent with elevated fibroblastic TGF-Β3, fmod -/- fibroblasts were significantly less motile than WT fibroblasts. fmod -/- fibroblasts were also more susceptible to migration inhibition by TGF-Β3, leading to profound delays in dermal cell migration. Increased scarring in fmod -/- mice indicates that TGF-Β3\u27s antimotility effects predominate over its antifibrotic effects when high TGF-Β3 levels disrupt early fibroblastic wound ingress. These studies demonstrate that FMOD presence is critical for proper temporospatial coordination of wound healing events and normal TGF-Β bioactivity. © 2011 The Society for Investigative Dermatology

    Emerged HA and NA Mutants of the Pandemic Influenza H1N1 Viruses with Increasing Epidemiological Significance in Taipei and Kaohsiung, Taiwan, 2009–10

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    The 2009 influenza pandemic provided an opportunity to observe dynamic changes of the hemagglutinin (HA) and neuraminidase (NA) of pH1N1 strains that spread in two metropolitan areas -Taipei and Kaohsiung. We observed cumulative increases of amino acid substitutions of both HA and NA that were higher in the post–peak than in the pre-peak period of the epidemic. About 14.94% and 3.44% of 174 isolates had one and two amino acids changes, respective, in the four antigenic sites. One unique adaptive mutation of HA2 (E374K) was first detected three weeks before the epidemic peak. This mutation evolved through the epidemic, and finally emerged as the major circulated strain, with significantly higher frequency in the post-peak period than in the pre-peak (64.65% vs 9.28%, p<0.0001). E374K persisted until ten months post-nationwide vaccination without further antigenic changes (e.g. prior to the highest selective pressure). In public health measures, the epidemic peaked at seven weeks after oseltamivir treatment was initiated. The emerging E374K mutants spread before the first peak of school class suspension, extended their survival in high-density population areas before vaccination, dominated in the second wave of class suspension, and were fixed as herd immunity developed. The tempo-spatial spreading of E374K mutants was more concentrated during the post–peak (p = 0.000004) in seven districts with higher spatial clusters (p<0.001). This is the first study examining viral changes during the naïve phase of a pandemic of influenza through integrated virological/serological/clinical surveillance, tempo-spatial analysis, and intervention policies. The vaccination increased the percentage of E374K mutants (22.86% vs 72.34%, p<0.001) and significantly elevated the frequency of mutations in Sa antigenic site (2.36% vs 23.40%, p<0.001). Future pre-vaccination public health efforts should monitor amino acids of HA and NA of pandemic influenza viruses isolated at exponential and peak phases in areas with high cluster cases

    Integrated Sr isotope variations and global environmental changes through the Late Permian to early Late Triassic

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    New 87Sr/86Sr data based on 127 well-preserved and well-dated conodont samples from South China were measured using a new technique (LA-MC-ICPMS) based on single conodont albid crown analysis. These reveal a spectacular climb in seawater 87Sr/86Sr ratios during the Early Triassic that was the most rapid of the Phanerozoic. The rapid increase began in Bed 25 of the Meishan section (GSSP of the Permian–Triassic boundary, PTB), and coincided closely with the latest Permian extinction. Modeling results indicate that the accelerated rise of 87Sr/86Sr ratios can be ascribed to a rapid increase (>2.8×) of riverine flux of Sr caused by intensified weathering. This phenomenon could in turn be related to an intensification of warming-driven runoff and vegetation die-off. Continued rise of 87Sr/86Sr ratios in the Early Triassic indicates that continental weathering rates were enhanced >1.9 times compared to those of the Late Permian. Continental weathering rates began to decline in the middle–late Spathian, which may have played a role in the decrease of oceanic anoxia and recovery of marine benthos. The 87Sr/86Sr values decline gradually into the Middle Triassic to an equilibrium values around 1.2 times those of the Late Permian level, suggesting that vegetation coverage did not attain pre-extinction levels thereby allowing higher runoff

    A Stratified Redox Model for the Ediacaran Ocean

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    Fluorescent nanoparticles for sensing

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    Nanoparticle-based fluorescent sensors have emerged as a competitive alternative to small molecule sensors, due to their excellent fluorescence-based sensing capabilities. The tailorability of design, architecture, and photophysical properties has attracted the attention of many research groups, resulting in numerous reports related to novel nanosensors applied in sensing a vast variety of biological analytes. Although semiconducting quantum dots have been the best-known representative of fluorescent nanoparticles for a long time, the increasing popularity of new classes of organic nanoparticle-based sensors, such as carbon dots and polymeric nanoparticles, is due to their biocompatibility, ease of synthesis, and biofunctionalization capabilities. For instance, fluorescent gold and silver nanoclusters have emerged as a less cytotoxic replacement for semiconducting quantum dot sensors. This chapter provides an overview of recent developments in nanoparticle-based sensors for chemical and biological sensing and includes a discussion on unique properties of nanoparticles of different composition, along with their basic mechanism of fluorescence, route of synthesis, and their advantages and limitations

    Towards a global partnership model in interprofessional education for cross-sector problem-solving

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    Objectives A partnership model in interprofessional education (IPE) is important in promoting a sense of global citizenship while preparing students for cross-sector problem-solving. However, the literature remains scant in providing useful guidance for the development of an IPE programme co-implemented by external partners. In this pioneering study, we describe the processes of forging global partnerships in co-implementing IPE and evaluate the programme in light of the preliminary data available. Methods This study is generally quantitative. We collected data from a total of 747 health and social care students from four higher education institutions. We utilized a descriptive narrative format and a quantitative design to present our experiences of running IPE with external partners and performed independent t-tests and analysis of variance to examine pretest and posttest mean differences in students’ data. Results We identified factors in establishing a cross-institutional IPE programme. These factors include complementarity of expertise, mutual benefits, internet connectivity, interactivity of design, and time difference. We found significant pretest–posttest differences in students’ readiness for interprofessional learning (teamwork and collaboration, positive professional identity, roles, and responsibilities). We also found a significant decrease in students’ social interaction anxiety after the IPE simulation. Conclusions The narrative of our experiences described in this manuscript could be considered by higher education institutions seeking to forge meaningful external partnerships in their effort to establish interprofessional global health education

    Fiber Loop Ringdown — a Time-Domain Sensing Technique for Multi-Function Fiber Optic Sensor Platforms: Current Status and Design Perspectives

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    Fiber loop ringdown (FLRD) utilizes an inexpensive telecommunications light source, a photodiode, and a section of single-mode fiber to form a uniform fiber optic sensor platform for sensing various quantities, such as pressure, temperature, strain, refractive index, chemical species, biological cells, and small volume of fluids. In FLRD, optical losses of a light pulse in a fiber loop induced by changes in a quantity are measured by the light decay time constants. FLRD measures time to detect a quantity; thus, FLRD is referred to as a time-domain sensing technique. FLRD sensors have near real-time response, multi-pass enhanced high-sensitivity, and relatively low cost (i.e., without using an optical spectral analyzer). During the last eight years since the introduction of the original form of fiber ringdown spectroscopy, there has been increasing interest in the FLRD technique in fiber optic sensor developments, and new application potential is being explored. This paper first discusses the challenging issues in development of multi-function, fiber optic sensors or sensor networks using current fiber optic sensor sensing schemes, and then gives a review on current fiber optic sensor development using FLRD technique. Finally, design perspectives on new generation, multi-function, fiber optic sensor platforms using FLRD technique are particularly presented

    Electronic structure of the iron-based superconductor LaOFeP

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    The recent discovery of superconductivity in the so-called iron-oxypnictide family of compounds has generated intense interest. The layered crystal structure with transition metal ions in planar square lattice form and the discovery of spin-density-wave order near 130 K seem to hint at a strong similarity with the copper oxide superconductors. A burning current issue is the nature of the ground state of the parent compounds. Two distinct classes of theories have been put forward depending on the underlying band structures: local moment antiferromagnetic ground state for strong coupling approach and itinerant ground state for weak coupling approach. The local moment magnetism approach stresses on-site correlations and proximity to a Mott insulating state and thus the resemblance to cuprates; while the latter approach emphasizes the itinerant electron physics and the interplay between the competing ferromagnetic and antiferromagnetic fluctuations. Such a controversy is partly due to the lack of conclusive experimental information on the electronic structures. Here we report the first angle-resolved photoemission spectroscopy (ARPES) investigation of LaOFeP (Tc = 5.9 K), the first reported iron-based superconductor. Our results favor the itinerant ground state, albeit with band renormalization. In addition, our data reveal important differences between these and copper based superconductors.Comment: 17 pages, 4 figure

    Measurement of azimuthal asymmetries in inclusive charged dipion production in e+ee^+e^- annihilations at s\sqrt{s} = 3.65 GeV

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    We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process e+eππXe^+e^-\rightarrow \pi\pi X based on a data set of 62 pb1\rm{pb}^{-1} at the center-of-mass energy s=3.65\sqrt{s}=3.65 GeV collected with the BESIII detector. These asymmetries can be attributed to the Collins fragmentation function. We observe a nonzero asymmetry, which increases with increasing pion momentum. As our energy scale is close to that of the existing semi-inclusive deep inelastic scattering experimental data, the measured asymmetries are important inputs for the global analysis of extracting the quark transversity distribution inside the nucleon and are valuable to explore the energy evolution of the spin-dependent fragmentation function.Comment: 7 pages, 5 figure

    Measurement of the e+eπ+π\mathrm e^+\mathrm e^-\rightarrow\mathrm\pi^+\mathrm\pi^- Cross Section between 600 and 900 MeV Using Initial State Radiation

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    We extract the e+eπ+πe^+e^-\rightarrow \pi^+\pi^- cross section in the energy range between 600 and 900 MeV, exploiting the method of initial state radiation. A data set with an integrated luminosity of 2.93 fb1^{-1} taken at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider is used. The cross section is measured with a systematic uncertainty of 0.9%. We extract the pion form factor Fπ2|F_\pi|^2 as well as the contribution of the measured cross section to the leading order hadronic vacuum polarization contribution to (g2)μ(g-2)_\mu. We find this value to be aμππ,LO(600900  MeV)=(368.2±2.5stat±3.3sys)1010a_\mu^{\pi\pi,\rm LO}(600-900\;\rm MeV) = (368.2 \pm 2.5_{\rm stat} \pm 3.3_{\rm sys})\cdot 10^{-10}.Comment: 14 pages, 7 figures, accepted by PL
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