238 research outputs found

    Role of Elastic Phonon Couplings in Dictating the Thermal Transport across Atomically Sharp SiC/Si Interfaces

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    Wide-bandgap (WBG) semiconductors have promising applications in power electronics due to their high voltages, radio frequencies, and tolerant temperatures. Among all the WBG semiconductors, SiC has attracted attention because of its high mobility, high thermal stability, and high thermal conductivity. However, the interfaces between SiC and the corresponding substrate largely affect the performance of SiC-based electronics. It is therefore necessary to understand and design the interfacial thermal transport across the SiC/substrate interfaces, which is critical for the thermal management design of these SiC-based power electronics. This work systematically investigates heat transfer across the 3C-SiC/Si, 4H-SiC/Si, and 6H-SiC/Si interfaces using non-equilibrium molecular dynamics simulations and diffuse mismatch model. We find that the room temperature ITC for 3C-SiC/Si, 4H-SiC/Si, and 6H-SiC/Si interfaces is 932 MW/m2K, 759 MW/m2K, and 697 MW/m2K, respectively. We also show the contribution of the ITC resulting from elastic scatterings at room temperature is 80% for 3C-SiC/Si interfaces, 85% for 4H-SiC/Si interfaces, and 82% for 6H-SiC/Si interfaces, respectively. We further find the ITC contributed by the elastic scattering decreases with the temperature but remains at a high ratio of 67%~78% even at an ultrahigh temperature of 1000 K. The reason for such a high elastic ITC is the large overlap between the vibrational density of states of Si and SiC at low frequencies (< ~ 18 THz), which is also demonstrated by the diffuse mismatch mode. It is interesting to find that the inelastic ITC resulting from the phonons with frequencies higher than the cutoff frequency of Si (i.e., ~18 THz) can be negligible. That may be because of the wide frequency gap between Si and SiC, which makes the inelastic scattering among these phonons challenging to meet the energy and momentum conservation rules

    Renal collecting duct carcinoma with extensive coagulative necrosis mimicking anemic infarct: report of a case and the literature review

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    Collecting duct carcinoma (CDC) with a mass of coagulative necrosis is very rare. We report here a case of CDC with extensive geographic coagulative necrosis mimicking anemic infarct with tumor cells embedded around the necrotic foci in a 73-years-old man. Histopathological examination showed that tumor nests near the necrotic foci were arranged as angulated tubules, tubulopapillary and glandular structures. Neoplastic cells had moderate to abundant eosinophilic cytoplasm and large hyperchromatic nuclei with prominent nucleoli as Fuhrman nuclear grade 3 or 4. The tumor cells were positive for pan-Cytokeratin, Vimentin, E-cadherin, CD10, and CK7, confirming the diagnosis as CDC. The patient is still alive 6 months later from nephrectomy, a long time following up is needed to learn the prognosis. Conclusively, morphology from different portions of the lesion, immunohistochemical stain and the combination analysis of the radiological features is essential to make a precise pathological diagnosis of CDC. And CDC should also be distinguished from clear cell renal cell carcinoma, renal medullary carcinoma, urothelial carcinoma with glandular differentiation, renal neuroendocrine tumor, renal epithelioid angiomyolipoma, renal pigmented paraganglioma and renal mesenchymal chondrosarcoma etc. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/126427052597503

    ATR-SEIRAS study of CO adsorption and oxidation on Rh modified Au(111-25 nm) film electrodes in 0.1 M H2SO4

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    Rh modified Au(111-25 nm) electrodes, prepared by electron beam evaporation and galvanostatic deposition, were employed to study adsorption and electro-oxidation of CO on Rh in 0.1 M sulfuric acid solution by in situ attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS). The results of ATR-SEIRAS experiments were compared with those obtained by infrared reflection absorption spectroscopy on three low-index Rh single crystal surfaces. The Rh film deposited on Au(111-25 nm) electrode consists of 3D clusters forming a highly stepped [n(111) × (111)]-like surface with narrow (111) terraces. When CO was dosed at the hydrogen adsorption potential region, CO adsorbed in both atop (COL) and bridge (COB) configurations, as well as coadsorbed water species, were detected on the Rh film electrode. A partial interconversion of spectroscopic bands due to the CO displacement from bridge to atop sites was found during the anodic potential scan, revealing that there is a potential-dependent preference of CO adsorption sites on Rh surfaces. Our data indicate that CO oxidation on Rh electrode surface in acidic media involves coadsorbed water and follows the nucleation and growth model of a Langmuir-Hinshelwood type reaction.The work was supported by the Research Center Jülich, the University of Bern, Swiss National Science Foundation (200020_144471, 200021-124643), the Spanish Ministerio de Economía y Competitividad (project CTQ2013-44083-P) and University of Alicante. QX acknowledges fellowships of the Research Center Jülich; IP acknowledges support by COST Action TD 1002; and AK acknowledges the financial support by CTI Swiss Competence Centers for Energy Research (SCCER Heat and Electricity Storage)

    Collaborative Vehicular Edge Computing Networks: Architecture Design and Research Challenges

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    The emergence of augmented reality (AR), autonomous driving and other new applications have greatly enriched the functionality of the vehicular networks. However, these applications usually require complex calculations and large amounts of storage, which puts tremendous pressure on traditional vehicular networks. Mobile edge computing (MEC) is proposed as a prospective technique to extend computing and storage resources to the edge of the network. Combined with MEC, the computing and storage capabilities of the vehicular network can be further enhanced. Therefore, in this paper, we explore the novel collaborative vehicular edge computing network (CVECN) architecture. We first review the work related to MEC and vehicular networks. Then we discuss the design principles of CVECN. Based on the principles, we present the detailed CVECN architecture, and introduce the corresponding functional modules, communication process, as well as the installation and deployment ideas. Furthermore, the promising technical challenges, including collaborative coalition formation, collaborative task offloading and mobility management, are presented. And some potential research issues for future research are highlighted. Finally, simulation results are verified that the proposed CVECN can significantly improve network performance

    Anti-inflammatory effect of Zanthoxylum bungeanum-cake-separated moxibustion on rheumatoid arthritis rats

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    Background: Zanthoxylum bungeanum-cake-separated moxibustion (ZBCS-moxi), a kind of traditional therapy of moxibustion, has been used in China since 340 B.C. However, its mechanism remains unclear. So, this study was attempted to reveal the anti-inflammatory effect of ZBCS-moxi on rheumatoid arthritis (RA) rats.Methods and Materials: Forty health SD female rats were randomly divided into 4 groups  (n=10/group): control group, model group, Zanthoxylum bungeanum-cake-separated moxibustion group (ZBCS-moxi group) and Aconitum carmichaeli-cake-separated moxibustion group (ACCS-moxi group). RA model was induced by injecting 0.1 ml Freund’s complete adjuvant (FCA) into the right hind paw of rats. Eleven days after CFA injection, the rats in ZBCS-moxi group received Zanthoxylum bungeanum- cake-separated moxibustion on Shenshu (BL23), Zusanli (ST36) acupoints and the dorsum right hind paw respectively for 3 weeks. The ACCS-moxi group was used as a positive control, while the rats were treated with Aconitum carmichaeli-cake-separated moxibustion on the same acupoints and courses. After a 3-week treatment, we investigated anti-inflammatory effect by measuring the paw volume,  observing the pathologic morphology of synovial membranes and detecting the concentration of IL-1β and TNF-α in serum.Results: Compared to model group, the swollen paw volumes, the synovial hyperplasia and pannus formation of synovial membranes and the concentration of IL-1β and TNF-α in serum decreased obviously (P&lt;0.01, P&lt;0.05) in ZBCS-moxi group, as well as in ACCS-moxi group. However, the swollen paw volumes, the synovial hyperplasia and pannus formation of synovial membranes and the concentration of IL-1β and TNF-α in serum in ZBCS-moxi and ACCS-moxi group did not show significant differences (P&gt;0.05)Conclusions: ZBCS-moxi displays anti-inflammatory effect on RA rats via suppressing the expression of cytokines and has similar effect to ACCS-moxi.Key words: Anti-inflammatory effect; Zanthoxylum bungeanum-cake-separated moxibustion; Aconitum carmichaeli-cake-separated moxibustion; Rheumatoid Arthritis

    Room-temperature correlated states in twisted bilayer MoS2_2

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    Moir\'e superlattices have emerged as an exciting condensed-matter quantum simulator for exploring the exotic physics of strong electronic correlations. Notable progress has been witnessed, but such correlated states are achievable usually at low temperatures. Here, we report the transport evidences of room-temperature correlated electronic states and layer-hybridized SU(4) Hubbard model simulator in AB-stacked MoS2_2 homo-bilayer moir\'e superlattices. Correlated insulating states at moir\'e band filling factors v = 1, 2, 3 are unambiguously established in twisted bilayer MoS2_2. Remarkably, the correlated electronic states can persist up to a record-high critical temperature of over 285 K. The realization of room-temperature correlated states in twisted bilayer MoS2_2 can be understood as the cooperation effects of the stacking-specific atomic reconstruction and the resonantly enhanced interlayer hybridization, which largely amplify the moir\'e superlattice effects on electronic correlations. Furthermore, extreme large non-linear Hall responses up to room-temperature are uncovered near correlated insulating states, demonstrating the quantum geometry of moir\'e flat conduction band.Comment: 13 pages, 3 figure

    Efficacy and Safety of Wei Bi Mei, a Chinese Herb Compound, as an Alternative to Bismuth for Eradication of Helicobacter pylori

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    Bismuth-containing quadruple therapy has been recommended as the first line of treatment in areas of high clarithromycin or metronidazole resistance. However, safety concerns of bismuth agents have long been raised. We first assessed the efficacy and safety of Wei Bi Mei granules, which are bismuth compounds consisting of three synthetic drugs and five medicinal herbs, compared to bismuth aluminate and colloidal bismuth subcitrate (CBS) in H. pylori-infected mouse model. We then used atomic fluorescence spectroscopy and autometallography to measure the accumulation of three bismuth agents in the brain, heart, liver, and kidneys in adult Sprague-Dawley rats. We also evaluated the safety of bismuth agents by conducting clinical biochemistry tests in blood samples of experimental animals. Wei Bi Mei granules exhibited the highest efficacy of anti-H. pylori activity and yielded the lowest bismuth accumulation when compared to CBS and bismuth aluminate. Our findings show that Wei Bi Mei granules are a safe Chinese medicinal herb with potent anti-H. pylori activity and can be considered as an alternative to current bismuth compounds. Thus, Wei Bi Mei granules merit further evaluation, particularly with regard to efficacy and safety when they are combined with other H. pylori eradication medications in the clinical setting

    TMS-evoked potential in the dorsolateral prefrontal cortex to assess the severity of depression disease: a TMS-EEG study

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    Objective: The combined use of transcranial magnetic stimulation and electroencephalography (TMS-EEG), as a powerful technique that can non-invasively probe the state of the brain, can be used as a method to study neurophysiological markers in the field of psychiatric disorders and discover potential diagnostic predictors. This study used TMS-evoked potentials (TEPs) to study the cortical activity of patients with major depressive disorder depression (MDD) and the correlation with clinical symptoms to provide an electrophysiological basis for the clinical diagnosis.Methods: A total of 41 patients and 42 healthy controls were recruited to study. Using TMS-EEG techniques to measure the left dorsolateral prefrontal cortex (DLPFC) ‘s TEP index and evaluate the clinical symptoms of MDD patients using the Hamilton Depression Scale-24 (HAMD-24).Results: MDD subjects performing TMS-EEG on the DLPFC showed lower cortical excitability P60 index levels than healthy controls. Further analysis revealed that the degree of P60 excitability within the DLPFC of MDD patients was significantly negatively correlated with the severity of depression.Conclusion: The low levels of P60 exhibited in DLPFC reflect low excitability in MDD; the P60 component can be used as a biomarker for MDD in clinical assessment tools
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