6,402 research outputs found

    Compression Stress-Induced Internal Magnetic Field in Bulky TiO2 Photoanodes for Enhancing Charge-Carrier Dynamics

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    Enhancing charge-carrier dynamics is imperative to achieve efficient photoelectrodes for practical photoelectrochemical devices. However, a convincing explanation and answer for the important question which has thus far been absent relates to the precise mechanism of charge-carrier generation by solar light in photoelectrodes. Herein, to exclude the interference of complex multi-components and nanostructuring, we fabricate bulky TiO2 photoanodes through physical vapor deposition. Integrating photoelectrochemical measurements and in situ characterizations, the photoinduced holes and electrons are transiently stored and promptly transported around the oxygen-bridge bonds and 5-coordinated Ti atoms to form polarons on the boundaries of TiO2 grains, respectively. Most importantly, we also find that compressive stress-induced internal magnetic field can drastically enhance the charge-carrier dynamics for the TiO2 photoanode, including directional separation and transport of charge carriers and an increase of surface polarons. As a result, bulky TiO2 photoanode with high compressive stress displays a high charge-separation efficiency and an excellent charge-injection efficiency, leading to 2 orders of magnitude higher photocurrent than that produced by a classic TiO2 photoanode. This work not only provides a fundamental understanding of the charge-carrier dynamics of the photoelectrodes but also provides a new paradigm for designing efficient photoelectrodes and controlling the dynamics of charge carriers

    ab initio modeling of open systems: charge transfer, electron conduction, and molecular switching of a C_{60} device

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    We present an {\it ab initio} analysis of electron conduction through a C60C_{60} molecular device. Charge transfer from the device electrodes to the molecular region is found to play a crucial role in aligning the lowest unoccupied molecular orbital (LUMO) of the C60C_{60} to the Fermi level of the electrodes. This alignment induces a substantial device conductance of 2.2×(2e2/h)\sim 2.2 \times (2e^2/h). A gate potential can inhibit charge transfer and introduce a conductance gap near EFE_F, changing the current-voltage characteristics from metallic to semi-conducting, thereby producing a field effect molecular current switch

    The TNFR1 antagonist Atrosimab reduces neuronal loss, glial activation and memory deficits in an acute mouse model of neurodegeneration

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    Abstract Tumor necrosis factor alpha (TNF-α) and its key role in modulating immune responses has been widely recognized as a therapeutic target for inflammatory and neurodegenerative diseases. Even though inhibition of TNF-α is beneficial for the treatment of certain inflammatory diseases, total neutralization of TNF-α largely failed in the treatment of neurodegenerative diseases. TNF-α exerts distinct functions depending on interaction with its two TNF receptors, whereby TNF receptor 1 (TNFR1) is associated with neuroinflammation and apoptosis and TNF receptor 2 (TNFR2) with neuroprotection and immune regulation. Here, we investigated the effect of administering the TNFR1-specific antagonist Atrosimab, as strategy to block TNFR1 signaling while maintaining TNFR2 signaling unaltered, in an acute mouse model for neurodegeneration. In this model, a NMDA-induced lesion that mimics various hallmarks of neurodegenerative diseases, such as memory loss and cell death, was created in the nucleus basalis magnocellularis and Atrosimab or control protein was administered centrally. We showed that Atrosimab attenuated cognitive impairments and reduced neuroinflammation and neuronal cell death. Our results demonstrate that Atrosimab is effective in ameliorating disease symptoms in an acute neurodegenerative mouse model. Altogether, our study indicates that Atrosimab may be a promising candidate for the development of a therapeutic strategy for the treatment of neurodegenerative diseases

    Effect of strain on surface diffusion in semiconductor heteroepitaxy

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    We present a first-principles analysis of the strain renormalization of the cation diffusivity on the GaAs(001) surface. For the example of In/GaAs(001)-c(4x4) it is shown that the binding of In is increased when the substrate lattice is expanded. The diffusion barrier \Delta E(e) has a non-monotonic strain dependence with a maximum at compressive strain values (e 0) studied. We discuss the consequences of spatial variations of both the binding energy and the diffusion barrier of an adatom caused by the strain field around a heteroepitaxial island. For a simplified geometry, we evaluate the speed of growth of two coherently strained islands on the GaAs(001) surface and identify a growth regime where island sizes tend to equalize during growth due to the strain dependence of surface diffusion.Comment: 10 pages, 8 figures, LaTeX2e, to appear in Phys. Rev. B (2001). Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

    Human Mas-related G protein-coupled receptors-X1 induce chemokine receptor 2 expression in rat dorsal root ganglia neurons and release of chemokine ligand 2 from the human LAD-2 mast cell line

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    Primate-specific Mas-related G protein-coupled receptors-X1 (MRGPR-X1) are highly enriched in dorsal root ganglia (DRG) neurons and induce acute pain. Herein, we analyzed effects of MRGPR-X1 on serum response factors (SRF) or nuclear factors of activated T cells (NFAT), which control expression of various markers of chronic pain. Using HEK293, DRG neuron-derived F11 cells and cultured rat DRG neurons recombinantly expressing human MRGPR-X1, we found activation of a SRF reporter gene construct and induction of the early growth response protein-1 via extracellular signal-regulated kinases-1/2 known to play a significant role in the development of inflammatory pain. Furthermore, we observed MRGPR-X1-induced up-regulation of the chemokine receptor 2 (CCR2) via NFAT, which is considered as a key event in the onset of neuropathic pain and, so far, has not yet been described for any endogenous neuropeptide. Up-regulation of CCR2 is often associated with increased release of its endogenous agonist chemokine ligand 2 (CCL2). We also found MRGPR-X1-promoted release of CCL2 in a human connective tissue mast cell line endogenously expressing MRGPR-X1. Thus, we provide first evidence to suggest that MRGPR-X1 induce expression of chronic pain markers in DRG neurons and propose a so far unidentified signaling circuit that enhances chemokine signaling by acting on two distinct yet functionally co-operating cell types. Given the important role of chemokine signaling in pain chronification, we propose that interruption of this signaling circuit might be a promising new strategy to alleviate chemokine-promoted pain

    The international effort: building the bridge for Translational Medicine: Report of the 1st International Conference of Translational Medicine (ICTM)

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    Background: Supported by the International Society for Translational Medicine (ISTM), Wenzhou Medical College and the First Affiliated Hospital of Wenzhou Medical College, the International Conference on Translational Medicine (ICTM) was held on October 22–23, 2011 in Wenzhou, China. Nearly 800 registrants attended the meeting, primarily representing institutes and hospitals in Europe, The United States of America, And Asia, and China. The meeting was chaired and organized by Dr. Xiangdong Wang, Xiaoming Chen, Richard Coico, Jeffrey M. Drazen, Richard Horton, Francesco M. Marincola, Laurentiu M. Popescu, Jia Qu and Aamir Shahzad. Findings: The meeting focused on the communication of the need to foster translational medicine (TM) by building and broadening bridges between basic research and clinical studies at the international level. The meeting included distinguished TM experts from academia, the pharmaceutical and diagnostics industries, government agencies, regulators, and clinicians and provided the opportunity to identify shared interests and efforts for collaborative approaches utilizing cutting edge technologies, innovative approaches and novel therapeutic interventions. The meeting defined the concept of TM in its two-way operational scheme and emphasized the need for bed to bench efforts based directly on clinical observation. Conclusions: It was the meeting participants’ realization that the shared main goals of TM include breaking the separation between clinic practice and basic research, establishing positive feedback by understanding the basis of expected and unexpected clinical outcomes and accelerating basic research relevant to human suffering. The primary objectives of the meeting were two-fold: to accelerate the two-way translation by informing the participants representing the different disciplines about the state of art activities around TM approaches; and to identify areas that need to be supported by redirecting limited resources as well as identifying new sources of funding. This report summarizes key concepts presented during the meeting representing the state-of-art translational research and salient aspects of the ensuing discussions

    Thermal Dileptons at LHC

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    We predict dilepton invariant-mass spectra for central 5.5 ATeV Pb-Pb collisions at LHC. Hadronic emission in the low-mass region is calculated using in-medium spectral functions of light vector mesons within hadronic many-body theory. In the intermediate-mass region thermal radiation from the Quark-Gluon Plasma, evaluated perturbatively with hard-thermal loop corrections, takes over. An important source over the entire mass range are decays of correlated open-charm hadrons, rendering the nuclear modification of charm and bottom spectra a critical ingredient.Comment: 2 pages, 2 figures, contributed to Workshop on Heavy Ion Collisions at the LHC: Last Call for Predictions, Geneva, Switzerland, 14 May - 8 Jun 2007 v2: acknowledgment include

    Measurement of the t(t)over-bar production cross section in the dilepton channel in pp collisions at √s=8 TeV

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    The top-antitop quark (t (t) over bar) production cross section is measured in proton-proton collisions at root s = 8 TeV with the CMS experiment at the LHC, using a data sample corresponding to an integrated luminosity of 5.3 fb(-1). The measurement is performed by analysing events with a pair of electrons or muons, or one electron and one muon, and at least two jets, one of which is identified as originating from hadronisation of a bottom quark. The measured cross section is 239 +/- 2 (stat.) +/- 11 (syst.) +/- 6 (lum.) pb, for an assumed top-quark mass of 172.5 GeV, in agreement with the prediction of the standard model
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