15,631 research outputs found

    New factors influencing G protein coupled receptors’ system functions

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    New factors such as the G protein coupled receptor (GPCR) surrounding’s chemical environment, cell membrane constituents, the existent gap junction, endogenous receptor affinity status and animal species have been shown to influence the GPCR physiology and variations of those factors can modify the functions of the GPCRs, thus highlighting the possibility to exploit these properties in different pharmacological fields which may lead to obtaining new therapeutic methods and applications. Furthermore, it might help in developing new research methods.Keywords: G protein coupled receptor; Pharmacodynamics facto

    A Cytotoxic, Co-operative Interaction Between Energy Deprivation and Glutamate Release From System x\u3csub\u3ec\u3c/sub\u3e\u3csup\u3e−\u3c/sup\u3e Mediates Aglycemic Neuronal Cell Death

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    The astrocyte cystine/glutamate antiporter (system xc−) contributes substantially to the excitotoxic neuronal cell death facilitated by glucose deprivation. The purpose of this study was to determine the mechanism by which this occurred. Using pure astrocyte cultures, as well as, mixed cortical cell cultures containing both neurons and astrocytes, we found that neither an enhancement in system xc− expression nor activity underlies the excitotoxic effects of aglycemia. In addition, using three separate bioassays, we demonstrate no change in the ability of glucose-deprived astrocytes—either cultured alone or with neurons—to remove glutamate from the extracellular space. Instead, we demonstrate that glucose-deprived cultures are 2 to 3 times more sensitive to the killing effects of glutamate or N-methyl-D-aspartate when compared with their glucose-containing controls. Hence, our results are consistent with the weak excitotoxic hypothesis such that a bioenergetic deficiency, which is measureable in our mixed but not astrocyte cultures, allows normally innocuous concentrations of glutamate to become excitotoxic. Adding to the burgeoning literature detailing the contribution of astrocytes to neuronal injury, we conclude that under our experimental paradigm, a cytotoxic, co-operative interaction between energy deprivation and glutamate release from astrocyte system xc− mediates aglycemic neuronal cell death

    Sub-TeV proton beam generation by ultra-intense laser irradiation of foil-and-gas target

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    A two-phase proton acceleration scheme using an ultra-intense laser pulse irradiating a proton foil with a tenuous heavier-ion plasma behind it is presented. The foil electrons are compressed and pushed out as a thin dense layer by the radiation pressure and propagate in the plasma behind at near the light speed. The protons are in turn accelerated by the resulting space-charge field and also enter the backside plasma, but without the formation of a quasistationary double layer. The electron layer is rapidly weakened by the space-charge field. However, the laser pulse originally behind it now snowplows the backside-plasma electrons and creates an intense electrostatic wakefield. The latter can stably trap and accelerate the pre-accelerated proton layer there for a very long distance and thus to very high energies. The two-phase scheme is verified by particle-in-cell simulations and analytical modeling, which also suggests that a 0.54 TeV proton beam can be obtained with a 10(23) W/cm(2) laser pulse. (C) 2012 American Institute of Physics. [doi:10.1063/1.3684658]Physics, Fluids & PlasmasSCI(E)EI0ARTICLE2null1

    Limbal Stem Cells and Corneal Epithelial Regeneration: Current Status and Prospectives

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    The clear cornea functions like a window that controls the entry of light for visual information and plays a protective role. The failure of appropriate repair following corneal injury results in loss of corneal function. The limbal region of the cornea is thought to serve as a unique reservoir of corneal epithelial stem cells where limbal stem cells (LSC) contributed to the regeneration of corneal epithelium. The deficiency of LSC (LSCD) results in the failed regeneration of corneal epithelium following injuries. In this review, we discuss the current knowledge of LSC and LSC-based transplantation for regeneration of corneal epithelium. We will first review the latest development of corneal structures. Next we will introduce the concept of LSC and the associated debates. Third, we will review different LSC-based transplantation methods for LSCD treatment and compare their advantages and disadvantages. Finally, we will discuss the improvements of regeneration of corneal epithelium.published_or_final_versio

    Standard model plethystics

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    We study the vacuum geometry prescribed by the gauge invariant operators of the minimal supersymmetric standard model via the plethystic program. This is achieved by using several tricks to perform the highly computationally challenging Molien-Weyl integral, from which we extract the Hilbert series, encoding the invariants of the geometry at all degrees. The fully refined Hilbert series is presented as the explicit sum of 1422 rational functions. We found a good choice of weights to unrefine the Hilbert series into a rational function of a single variable, from which we can read off the dimension and the degree of the vacuum moduli space of the minimal supersymmetric standard model gauge invariants. All data in Mathematica format are also presented

    Study on the stability of retained austenite in marine steel

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    The residual austenite stability in marine steel was studied by different heat treatment processes. After heat-treatment process 1 (quenching + tempering) and heat treatment process 2 (quenching + intercritical annealing + tempering), the austenite content was determined by X-ray diffraction (XRD), and the microstructure of the test steel was tested by Scanning electron microscope (SEM), Transmission electron microscope(TEM), and Electron Backscattered Diffraction (EBSD). Experimental results showed that the microstructure of the test steel consisted of martensite/ bainite + ferrite + retained austenite. The retained austenite volume fractions were 20,8 % and 18,1 %, respectively, for process 1 and process 2.The retained austenite morphology, C content, distribution, and grain size all affect a steel’s thermal and mechanical stability. Film-like residual austenite with high C content and fine grain size has the best stability

    Study on the stability of retained austenite in marine steel

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    The residual austenite stability in marine steel was studied by different heat treatment processes. After heat-treatment process 1 (quenching + tempering) and heat treatment process 2 (quenching + intercritical annealing + tempering), the austenite content was determined by X-ray diffraction (XRD), and the microstructure of the test steel was tested by Scanning electron microscope (SEM), Transmission electron microscope(TEM), and Electron Backscattered Diffraction (EBSD). Experimental results showed that the microstructure of the test steel consisted of martensite/ bainite + ferrite + retained austenite. The retained austenite volume fractions were 20,8 % and 18,1 %, respectively, for process 1 and process 2.The retained austenite morphology, C content, distribution, and grain size all affect a steel’s thermal and mechanical stability. Film-like residual austenite with high C content and fine grain size has the best stability

    Resilient routing mechanism for wireless sensor networks with deep learning link reliability prediction

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    Wireless sensor networks play an important role in Internet of Things systems and services but are prone and vulnerable to poor communication channel quality and network attacks. In this paper we are motivated to propose resilient routing algorithms for wireless sensor networks. The main idea is to exploit the link reliability along with other traditional routing metrics for routing algorithm design. We proposed firstly a novel deep-learning based link prediction model, which jointly exploits Weisfeiler-Lehman kernel and Dual Convolutional Neural Network (WL-DCNN) for lightweight subgraph extraction and labelling. It is leveraged to enhance self-learning ability of mining topological features with strong generality. Experimental results demonstrate that WL-DCNN outperforms all the studied 9 baseline schemes over 6 open complex networks datasets. The performance of AUC (Area Under the receiver operating characteristic Curve) is improved by 16% on average. Furthermore, we apply the WL-DCNN model in the design of resilient routing for wireless sensor networks, which can adaptively capture topological features to determine the reliability of target links, especially under the situations of routing table suffering from attack with varying degrees of damage to local link community. It is observed that, compared with other classical routing baselines, the proposed routing algorithm with link reliability prediction module can effectively improve the resilience of sensor networks while reserving high-energy-efficiency
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