9,745 research outputs found

    Trustworthiness Management in Sharing CDN Infrastructure

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    Sharing Content Delivery Network (CDN) technologies such as CDN interconnection and cloud-based CDN have facilitated access to the huge volume of content in a cost-effective way. However, content distribution through shared CDN nodes is vulnerable to a wide variety of uncertainties, including unexpected node failure, intentional node disruption for maintenance or potential discrimination of content based on ownership. Trustworthiness can be considered as a key property to overcome the perception of uncertainty before delivering content through sharing CDN infrastructure and provide reliable broadcasting and telecommunications services. Establishing trustworthiness in sharing CDN infrastructure is a challenging task in the absence of the referenced framework. Therefore, we propose a trustworthiness management framework for sharing CDN infrastructure

    Selenium nanoparticles as candidates for antibacterial substitutes and supplements against multidrug-resistant bacteria

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    In recent years, multidrug-resistant (MDR) bacteria have increased rapidly, representing a major threat to human health. This problem has created an urgent need to identify alternatives for the treatment of MDR bacteria. The aim of this study was to identify the antibacterial activity of selenium nanoparticles (SeNPs) and selenium nanowires (SeNWs) against MDR bacteria and assess the potential synergistic effects when combined with a conventional antibiotic (linezolid). SeNPs and SeNWs were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), zeta potential, and UV-visible analysis. The antibacterial effects of SeNPs and SeNWs were confirmed by the macro-dilution minimum inhibi-tory concentration (MIC) test. SeNPs showed MIC values against methicillin-sensitive S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), vancomycin-resistant S. aureus (VRSA), and vanco-mycin-resistant enterococci (VRE) at concentrations of 20, 80, 320, and >320 Ī¼g/mL, respectively. On the other hand, SeNWs showed a MIC value of >320 Ī¼g/mL against all tested bacteria. Therefore, MSSA, MRSA, and VRSA were selected for the bacteria to be tested, and SeNPs were selected as the antimicrobial agent for the following experiments. In the time-kill assay, SeNPs at a concentration of 4X MIC (80 and 320 Ī¼g/mL) showed bactericidal effects against MSSA and MRSA, respectively. At a concentration of 2X MIC (40 and 160 Ī¼g/mL), SeNPs showed bacteriostatic effects against MSSA and bactericidal effects against MRSA, respectively. In the synergy test, SeNPs showed a synergistic effect with linezolid (LZD) through protein degradation against MSSA and MRSA. In conclusion, these results suggest that SeNPs can be candidates for antibacterial substitutes and supplements against MDR bacteria for topical use, such as dressings. However, for use in clinical situations, additional experiments such as toxicity and synergistic mechanism tests of SeNPs are needed

    Perpendicular magnetic anisotropy of two-dimensional Rashba ferromagnets

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    We compute the magnetocrystalline anisotropy energy within two-dimensional Rashba models. For a ferromagnetic free-electron Rashba model, the magnetic anisotropy is exactly zero regardless of the strength of the Rashba coupling, unless only the lowest band is occupied. For this latter case, the model predicts in-plane anisotropy. For a more realistic Rashba model with finite band width, the magnetic anisotropy evolves from in-plane to perpendicular and back to in-plane as bands are progressively filled. This evolution agrees with first-principles calculations on the interfacial anisotropy, suggesting that the Rashba model captures energetics leading to anisotropy originating from the interface provided that the model takes account of the finite Brillouin zone. The results show that the electron density modulation by doping or an external voltage is more important for voltage-controlled magnetic anisotropy than the modulation of the Rashba parameter.115Ysciescopu

    Intrinsic spin torque without spin-orbit coupling

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    We derive an intrinsic contribution to the nonadiabatic spin torque for nonuniform magnetic textures. It differs from previously considered contributions in several ways and can be the dominant contribution in some models. It does not depend on the change in occupation of the electron states due to the current flow but rather is due to the perturbation of the electronic states when an electric field is applied. Therefore it should be viewed as electric-field-induced rather than current-induced. Unlike previously reported nonadiabatic spin torques, it does not originate from extrinsic relaxation mechanisms or spin-orbit coupling. This intrinsic nonadiabatic spin torque is related by a chiral connection to the intrinsic spin-orbit torque that has been calculated from the Berry phase for Rashba systems.1197Ysciescopu

    Magnetization-controlled spin transport in DyAs/GaAs layers

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    Electrical transport properties of DyAs epitaxial layers grown on GaAs have been investigated at various temperatures and magnetic fields up to 12T. The measured longitudinal resistances show two distinct peaks at fields around 0.2 and 2.5T which are believed to be related to the strong spin-disorder scattering occurring at the phase transition boundaries induced by external magnetic field. An empirical magnetic phase diagram is deduced from the temperature dependent experiment, and the anisotropic transport properties are also presented for various magnetic field directions with respect to the current flow.Comment: 3 pages with 3 figure

    Effect of microstructural change on magnetic property of Mn-implanted p-type GaN

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    The Mn ions were implanted into p-type GaN and annealed to achieve a dilute magnetic semiconductor. The ferromagnetic property was obtained and attributed to the formation of Ga-Mn magnetic phases. The ferromagnetic signal was reduced and antiferromagnetic Mn-N compounds were produced at higher temperature annealing at 900 ??C. Results showed that N vacancies play a crucial role in weakening the ferromagnetic property in the Mn-implanted GaN.open586

    Atrial fibrillation: Prevention and termination with pacing

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    Ginseng for erectile dysfunction

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    BACKGROUND: Dietary supplements with ginseng, or ginseng alone, are widely used for a broad range of conditions, including erectile dysfunction. Ginseng is particularly popular in Asian countries. Individual studies assessing its effects are mostly small, of uneven methodological quality and have unclear results. OBJECTIVES: To assess the effects of ginseng on erectile dysfunction. SEARCH METHODS: We conducted systematic searches on multipleĀ electronic databases, including CENTRAL, MEDLINE, Embase, CINAHL, AMED, and loco-regional databases of east Asia, from their inceptions to 30 January 2021 without restrictions on language and publication status. Handsearches included conference proceedings. SELECTION CRITERIA: We included randomized or quasi-randomized controlled trials that evaluated the use of any type of ginseng as a treatment for erectile dysfunction compared to placebo or conventional treatment. DATA COLLECTION AND ANALYSIS: Two authors independently classified studies and three authors independently extracted data and assessed risk of bias in the included studies. We rated the certainty of evidence according to the GRADE approach. MAIN RESULTS: We included nine studies with 587 men with mild to moderate erectile dysfunction, aged from 20 to 70 years old. The studies all compared ginseng to placebo. We found only short-term follow-up data (up to 12 weeks).Ā  Primary outcomes Ginseng appears to have a trivial effect onĀ erectile dysfunction when compared to placebo based on the Erectile Function Domain of the International Index of Erectile Function (IIEF)-15 instrument (scale: 1 to 30, higher scores imply better function; mean difference [MD] 3.52, 95% confidence interval [CI] 1.79 to 5.25; IĀ² = 0%; 3 studies; low certainty evidence) assumingĀ a minimal clinically important difference (MCID) of 4.Ā  GinsengĀ probably also has a trivial effect on erectile function when compared to placebo based on the IIEF-5 instrument (scale: 1 to 25, higher scores imply better function; MD 2.39, 95% CI 0.89 to 3.88; IĀ² = 0%; 3 studies; moderate certainty evidence)Ā assumingĀ a MCIDĀ of 5. Ginseng may have little to no effect on adverse events compared to placeboĀ (risk ratio [RR] 1.45, 95% CI 0.69 to 3.03; IĀ² = 0%; 7 studies; low certainty evidence). Based on 86Ā adverse events per 1000 men in the placebo group, this would correspond to 39Ā more adverse events per 1000 (95% CI 27Ā fewer to 174Ā more). Secondary outcomes Ginseng may improve men's self-reportedĀ ability to have intercourse (RR 2.55, 95% CI 1.76 to 3.69; IĀ² = 23%; 6 studies; low certainty evidence). Based on 207 per 1000 men self-reporting the ability to have intercourse in the placebo group,Ā this wouldĀ correspond to 321 more menĀ (95% CI 158 more to 558 more)Ā per 1000 self-reporting the ability to have intercourse. Ginseng may have a trivial effect on men's satisfaction with intercourse based on the Intercourse Satisfaction Domain of the IIEF-15 (scale: 0 to 15, higher scores imply greaterĀ satisfaction; MD 1.19, 95% CI 0.41 to 1.97; IĀ²=0%; 3 studies; low certainty evidence) based on a MCID of 25% improvement from baseline. It may also have a trivial effect on men's satisfaction with intercourse based on item 5 of the IIEF-5 (scale: 0 to 5, higher scores imply more satisfaction; MD 0.60, 95% CI 0.02 to 1.18; 1 study; low certainty evidence) based on a MCID ofĀ 25% improvement from baseline. No study reported quality of life as an outcome. We found no trial evidence to inform comparisons to other treatments for erectile dysfunction, such as phosphodiesterase-5 inhibitors. We were unableĀ to conduct any predefined subgroup analyses. AUTHORS' CONCLUSIONS: Based on mostly low certainty evidence, ginseng may only have trivial effects on erectile function or satisfaction with intercourse compared to placebo when assessed using validated instruments. Ginseng may improve men's self-reportedĀ ability to have intercourse. It may have little to no effect on adverse events. We found no trial evidence comparing ginseng to other agents with a more established role in treatingĀ erectile dysfunction, such asĀ phosphodiesterase-5 inhibitors

    Effect of farnesyltransferase inhibitor R115777 on mitochondria of plasmodium falciparum

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    The parasite Plasmodium falciparum causes severe malaria and is the most dangerous to humans. However, it exhibits resistance to their drugs. Farnesyltransferase has been identified in pathogenic protozoa of the genera Plasmodium and the target of farnesyltransferase includes Ras family. Therefore, the inhibition of farnesyltransferase has been suggested as a new strategy for the treatment of malaria. However, the exact functional mechanism of this agent is still unknown. In addition, the effect of farnesyltransferase inhibitor (FTIs) on mitochondrial level of malaria parasites is not fully understood. In this study, therefore, the effect of a FTI R115777 on the function of mitochondria of P. falciparum was investigated experimentally. As a result, FTI R115777 was found to suppress the infection rate of malaria parasites under in vitro condition. It also reduces the copy number of mtDNA-encoded cytochrome c oxidase III. In addition, the mitochondrial membrane potential (Delta psi m) and the green fluorescence intensity of MitoTracker were decreased by FTI R115777. Chloroquine and atovaquone were measured by the mtDNA copy number as mitochondrial non-specific or specific inhibitor, respectively. Chloroquine did not affect the copy number of mtDNA-encoded cytochrome c oxidase III, while atovaquone induced to change the mtDNA copy number. These results suggest that FTI R115777 has strong influence on the mitochondrial function of P. falciparum. It may have therapeutic potential for malaria by targeting the mitochondria of parasites.1133Ysciescopu

    Finite Element Modelling for the Investigation of Edge Effect in Acoustic Micro Imaging of Microelectronic Packages

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    In acoustic micro imaging of microelectronic packages, edge effect is often presented as artifacts of C-scan images, which may potentially obscure the detection of defects such as cracks and voids in the solder joints. The cause of edge effect is debatable. In this paper, a two-dimensional finite element model is developed on the basis of acoustic micro imaging of a flip-chip package using a 230 MHz focused transducer to investigate acoustic propagation inside the package in attempt to elucidate the fundamental mechanism that causes the edge effect. A virtual transducer is designed in the finite element model to reduce the coupling fluid domain, and its performance is characterised against the physical transducer specification. The numerical results showed that the Under Bump Metallization (UBM) structure inside the package has a significant impact on the edge effect. Simulated wavefields also showed that the edge effect is mainly attributed to the horizontal scatter, which is observed in the interface of silicon die-to-the outer radius of solder bump. The horizontal scatter occurs even for a flip-chip package without the UBM structure
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