4,794 research outputs found

    Non-thermal WIMP baryogenesis

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    We propose a WIMP baryogensis achieved by the annihilation of non-thermally produced WIMPs from decay of heavy particles, which can result in low reheating temerature. Dark matter (DM) can be produced non-thermally during a reheating period created by the decay of long-lived heavy particle, and subsequently re-annihilate to lighter particles even after the thermal freeze-out. The re-annihilation of DM provides the observed baryon asymmetry as well as the correct relic density of DM. We investigate how wahout effects can affect the generation of the baryon asymmetry and study a model suppressing them. In this scenario, we find that DM can be heavy enough and its annihilation cross section can also be larger than that adopted in the usual thermal WIMP baryogenesis.Comment: 5 pages, 6 figure

    A survey on network simulators in three-dimensional wireless ad hoc and sensor networks

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    © 2016 The Author(s). As steady research in wireless ad hoc and sensor networks is going on, performance evaluation through relevant network simulator becomes indispensable procedure to demonstrate superiority to comparative schemes and suitability in most literatures. Thus, it is very important to establish credibility of simulation results by investigating merits and limitations of each simulator prior to selection. Based on this motivation, in this article, we present a comprehensive survey on current network simulators for new emerging research area, three-dimensional wireless ad hoc and sensor networks which is represented by airborne ad hoc networks and underwater sensor networks by reviewing major existing simulators as well as presenting their main features in several aspects. In addition, we address the outstanding mobility models which are main components in simulation study for self-organizing ad hoc networks. Finally, open research issues and research challenges are discussed and presented

    Ixeris dentata (Thunb) Nakai attenuates cognitive impairment in MPTP-treated mouse model of Parkinson's disease

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    Purpose: To evaluate the cognition-enhancing effect of Ixeris dentata (Thunb) Nakai in a mouse model of Parkinson's disease (PD). Methods: MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced mouse model of PD was used to evaluate the effect of Ixeris dentata (IDE) extract on the alteration of behavioral responses using rotarod and passive avoidance tests. The effect of IDE on oxidative stress levels were analyzed based on superoxide dismutase (SOD) and catalase (CAT) enzyme levels, and lipid peroxidation (LPO) in brain tissues. Results: MPTP (20 mg/kg, ip)-induced mice resulted in a significant (p < 0.01) behavioral deficiencies in locomotor behavior (from 53.15 ± 1.01 to 23.56 ± 1.04) and cognitive functions (from 297 ± 2.47 to 201.17 ± 3.23 s) compared with their respective control groups. Administration of IDE (20, 40 and 80 mg/kg, po) for three weeks significantly and dose-dependently improved (p < 0.001 at 80 mg/kg) locomotor and cognitive deficits in MPTP- treated mice. IDE treatment also significantly (p < 0.01 at 80 mg/kg) inhibited decrease in superoxide dismutase and catalase enzyme activities, and lipid peroxides in MPTP-treated mice in brain tissues. Conclusion: IDE exhibits good protection against MPTP-induced behavioral deficits via potential antioxidant defense mechanisms. Therefore, IDE could potentially be developed as a therapeutic approach for the treatment of neurodegenerative diseases. Keywords: Ixeris dentata, Neurodegenerative disease, MPTP, Parkinson's disease, Oxidative stres

    Emergency microsurgical embolectomy in acute ischemic stroke with diffusion-negative MRI

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    Although diffusion-weighted imaging (DWI) is highly sensitive and specific for the detection of acute ischemic injury, there are increasing reports that it may fail to demonstrate an acute stroke. Here, we present a case involving an acute ischemic stroke with a false-negative DWI in a 64-year-old woman who had undergone an emergency microsurgical embolectomy for an occluded middle cerebral artery (MCA). Although the endovascular mechanical embolectomy failed in treating the occluded MCA, we were able to successfully treat our patient with the second treatment option of a microsurgical embolectomy. Microsurgical embolectomy might be the treatment of choice, especially if the mechanical catheter is expected to not be able to access the target artery due to tortuous vascular structures

    Luxury Fashion Consumption: The Interplay of Guilt and Pleasure

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    We draw on the Affect Balance Theory to (a) explore whether two distinct modes of luxury consumption (i.e., conspicuous consumption and style consumption) are related to pleasure (i.e., positive affect) and guilt (i.e., negative affect); and (b) determine whether pleasure and guilt interplay to make interactive impacts, as well as independent impacts, on consumers’ repurchase intention

    Bisphosphonate inhibits the expression of cyclin A2 at the transcriptional level in normal human oral keratinocytes.

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    Nitrogen-containing bisphosphonates (N-BPs) are the most widely used anti-resorptive agents in the treatment of bone-related diseases. N-BPs inhibit bone resorption by specifically targeting osteoclasts, bone-resorbing cells. However, soft tissue toxicity, such as oral or gastrointestinal (GI) ulcerations has frequently been reported in N-BP users, suggesting that N-BPs may also directly target cells other than osteoclasts. Previously, we reported that BPs inhibit proliferation without inducing the apoptosis of normal human oral keratinocytes (NHOKs). However, the molecular mechanisms through which N-BPs inhibit the proliferation of NHOKs are not yet fully understood. In this study, we performed gene expression profiling in N-BP-treated NHOKs and identified cyclin A2 as one of the most commonly downregulated genes. When the NHOKs were treated with N-BPs, we found that the level of cyclin A2 was suppressed in a dose- and time-dependent manner. In addition, the protein level of cyclin A2 was also significantly lower in oral epithelial cells in N-BP-treated oral mucosal tissue constructs. Cyclin A2 promoter reporter assay revealed that N-BPs inhibited the luciferase activity, indicating that the inhibition of cyclin A2 expression occurs at the transcriptional level. Furthermore, N-BPs did not alter the expression of cyclin A2 in normal human oral fibroblasts (NHOFs), suggesting that the effect of N-BPs on cyclin A2 expression may be cell-type specific. Thus, the findings of our study demonstrate that the inhibition of NHOK proliferation by N-BPs is mediated, at least in part, by the suppression of cyclin A2 expression at the transcriptional level, which may explain the underlying mechanisms of soft tissue toxicity by N-BPs
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