218 research outputs found

    AN EFFICIENT SOLUTION OF THE ELASTIC MECHANISM NON-LINEAR DIFFERENTIAL EQUATION OF MOTION

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    ABSTRACT A general form of non-linear differential motion equations for the elastic mechanism is presented. Based on the analysis of the structure property of the equations, a numerical solution method which combines the State Space Method with Iterative Method is put forward. The solution efficiency and precision are improved greatly through analyzing the solution method of the matrix exponent function and the equations with belt shape and side block coefficient matrices. Finally, as an example, the dynamic properties of a mold oscillation mechanism with 4-eccentric axes for continuous casting machine are analyzed. The results illustrate the correctness and feasibility of the method

    Tuning Thermal Conductivity of Hybrid Perovskites through Halide Alloying

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    Tuning the thermal transport properties of hybrid halide perovskites is critical for their applications in optoelectronics, thermoelectrics, and photovoltaics. Here, we demonstrate an effective strategy to modulate the thermal transport property of hybrid perovskites by halide alloying. A highly tunable thermal conductivity of mixed-halide hybrid perovskites is achieved due to halide-alloying and structural distortion. Our experimental measurements show that the room temperature thermal conductivity of MAPb(BrxI1-x)3 (x = 0-1) can be largely modulated from 0.27 W/mK (x = 0.5) to 0.47 W/mK (x = 1). Molecular dynamics simulations further demonstrate that the thermal conductivity reduction of hybrid halide perovskites results from the suppression of the mean free paths of the low-frequency acoustic and optical phonons. It is found that halide alloying and the induced structural distortion can largely increase the scatterings of optical and acoustic phonons, respectively. The confined diffusion of MA+ cations in the octahedra cage is found to act as an additional thermal transport channel in hybrid perovskites and can contribute around 10-20% of the total thermal conductivity. Our findings provide a strategy for tailoring the thermal transport in hybrid halide perovskites which may largely benefit their related applications

    Research Progress of Bacteriocins from Lactic Acid Bacteria Based on Bibliometric Analysis

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    Bacteriocins from lactic acid bacteria are kinds of natural proteins or peptides with antibacterial activities produced by lactic acid bacteria in the process of metabolism. They have the advantages of non-drug resistance, biodegradation, good antibacterial activity, etc., which have broad application prospects in food, medicine and feed fields. Based on bibliometrics, the literatures related to bacteriocins from lactic acid bacteria are searched in CNKI database and Web of Science (WOS) core collection database from 2000 to 2023, obtains 627 Chinese literatures and 2543 English literatures. CiteSpace software is used to analyze the research status and hot spots in this field from the perspective of annual number of published papers, core countries, authors, institutions and journals, highly cited literatures, keyword co-occurrence and co-clustering, etc.. The results show that the number of literatures has an increasing trend from 2000 to 2022. Spain, India and China are the top three countries in terms of number of literatures. The authors with the highest number of publications in CNKI database and WOS database are LI Pinglan from China Agricultural University and Todorov SD from University of Sao Paulo in Brazil, respectively. The journals with the highest number of publications are “Science and Technology of Food Industry” and “Journal of Appled Micbiogy”. In the CNKI database, keyword analysis reveals that most of the literatures are isolated, screened and identified from different food samples to obtain bacteriocin-producing lactic acid bacteria, and further evaluates the antibacterial activity of bacteriocins, and discusses the application in the food industry. The analysis of burst words shows that the focus of current research are antibacterial mechanism of bacteriocin and the relationship between bacteriocin and probiotics. In WOS database, the keywords of "gastrointestinal tract", "genetic characteristics", "Listeria mononucleogenes" and "antibacterial activity" appears more frequently. The main focus is the mining of bacteriocins from lactic acid bacteria toward antibiotic-resistant bacteria, and analysis of the genetic characteristics. The comprehensive analysis provides a reference and help for Chinese scientific researchers to engage in related research and predict the future development trend of the industry

    Transformer-based Acoustic Modeling for Hybrid Speech Recognition

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    We propose and evaluate transformer-based acoustic models (AMs) for hybrid speech recognition. Several modeling choices are discussed in this work, including various positional embedding methods and an iterated loss to enable training deep transformers. We also present a preliminary study of using limited right context in transformer models, which makes it possible for streaming applications. We demonstrate that on the widely used Librispeech benchmark, our transformer-based AM outperforms the best published hybrid result by 19% to 26% relative when the standard n-gram language model (LM) is used. Combined with neural network LM for rescoring, our proposed approach achieves state-of-the-art results on Librispeech. Our findings are also confirmed on a much larger internal dataset.Comment: to appear in ICASSP 202

    Investigating the L-Glu-NMDA receptor-H2S-NMDA receptor pathway that regulates gastric function in rats’ nucleus ambiguus

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    BackgroundIn previous investigations, we explored the regulation of gastric function by hydrogen sulfide (H2S) and L-glutamate (L-Glu) injections in the nucleus ambiguus (NA). We also determined that both H2S and L-Glu have roles to play in the physiological activities of the body, and that NA is an important nucleus for receiving visceral sensations. The purpose of this study was to explore the potential pathway link between L-Glu and H2S, resulting in the regulation of gastric function.MethodsPhysiological saline (PS), L-glutamate (L-Glu, 2 nmol), NaHS (2 nmol), D-2-amino-5-phopho-novalerate (D-AP5, 2 nmol) + L-Glu (2 nmol), aminooxyacetic acid (AOAA, 2 nmol) + L-Glu (2 nmol), D-AP5 (2 nmol) + NaHS (2 nmol) were injected into the NA. A balloon was inserted into the stomach to observe gastric pressure and for recording the changes of gastric smooth muscle contraction curve. The gastric fluid was collected by esophageal perfusion and for recording the change of gastric pH value.ResultsInjecting L-Glu in NA was found to significantly inhibit gastric motility and promote gastric acid secretion in rats (p < 0.01). On the other hand, injecting the PS, pre-injection N-methyl-D-aspartate (NMDA) receptor blocker D-AP5, cystathionine beta-synthase (CBS) inhibitor AOAA and re-injection L-Glu did not result in significant changes (p > 0.05). The same injection NaHS significantly inhibit gastric motility and promote gastric acid secretion in rats (p < 0.01), but is eliminated by injection D-AP5 (p > 0.05).ConclusionThe results indicate that both exogenous L-Glu and H2S injected in NA regulate gastric motility and gastric acid secretion through NMDA receptors. This suggests that NA has an L-Glu-NMDA receptor-CBS-H2S pathway that regulates gastric function

    Treatment experience for different risk groups of Kaposiform hemangioendothelioma

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    BackgroundKaposiform hemangioendothelioma (KHE) is a rare vascular tumor with a high risk of mortality. Few studies with large samples of KHE have been reported. KHE may develop into the Kasabach–Merritt phenomenon (KMP), which is characterized by thrombocytopenia and consumptive coagulopathy. The features of severe symptomatic anemia and life-threatening low platelets make the management of KHE associated with KMP challenging.ObjectiveThe aim of this study was to examine the clinical characteristics of patients with KHE and discuss the treatment experience for different risk groups of KHE.MethodsThrough a retrospective review of 70 patients diagnosed with KHE between 2017 and 2022 in our center, we classify lesions into three clinicopathological stages based on the tumor involving depth, and divided the severity of KHE into three levels by estimating clinicopathological stages and severity of thrombocytopenia. Treatments of different severity groups were estimated with sufficient data.ResultsIn our cohort, 27% were neonates, and KHE lesion occurred at birth in 84% of patients. There was a slight male predominance (32 girls and 38 boys). Common clinical characteristics included associated coagulation disorder (100%), locally aggressive cutaneous blue–purple mass (89%), thrombocytopenia (78%), and local pain or joint dysfunction (20%). The lower extremities were the dominant location (35%), followed by the trunk (29%), the maxillofacial region and neck (24%), and the upper extremities (10%). Of the total cohort, 78% developed KMP; the median age at which thrombocytopenia occurred was 27.8 days. The median platelet count of patients who were associated with KMP was 24,000/”L in our cohort. Ninety-two percent of patients were given surgery treatment and 89% of these patients were given high-dose methylprednisolone (5-6 mg/kg daily) before surgery. In 55 patients with KMP, 36% were sensitive to high-dose corticosteroid therapy. Patients from the low-risk group (eight cases) underwent operation, all of whom recovered without recurrence after a maximum follow-up of 5 years. Out of 26 patients from the high-risk group, 25 underwent surgery treatment, with 1 case undergoing secondary surgery after recurrence and 1 case taking sirolimus. Out of 36 cases from the extremely high-risk group, 32 underwent surgery (including 2 cases who underwent external carotid artery ligation and catheterization), 3 of whom underwent secondary operation after recurrence, and the remaining 4 cases took medicine. The mean length of having sirolimus was 21 months; two cases stopped taking sirolimus due to severe pneumonia. Two cases died at 1 and 3 months after discharge.ConclusionsOur study describes the largest assessment of high-risk patients with KHE who have undergone an operation to date, with 5 years of follow-up to track recovery, which provides invaluable knowledge for the future treatment of patients with KHE and KMP from different risk groups: Early surgical intervention may be the most definitive treatment option for most patients with KHE; multimodality treatment is the best choice for the extremely high-risk group

    High-Level Expression of Notch1 Increased the Risk of Metastasis in T1 Stage Clear Cell Renal Cell Carcinoma

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    Background: Although metastasis of clear cell renal cell carcinoma (ccRCC) is basically observed in late stage tumors, T1 stage metastasis of ccRCC can also be found with no definite molecular cause resulting inappropriate selection of surgery method and poor prognosis. Notch signaling is a conserved, widely expressed signal pathway that mediates various cellular processes in normal development and tumorigenesis. This study aims to explore the potential role and mechanism of Notch signaling in the metastasis of T1 stage ccRCC. Methodology/Principal Findings: The expression of Notch1 and Jagged1 were analyzed in tumor tissues and matched normal adjacent tissues obtained from 51 ccRCC patients. Compared to non-tumor tissues, Notch1 and Jagged1 expression was significantly elevated both in mRNA and protein levels in tumors. Tissue samples of localized and metastatic tumors were divided into three groups based on their tumor stages and the relative mRNA expression of Notch1 and Jagged1 were analyzed. Compared to localized tumors, Notch1 expression was significantly elevated in metastatic tumors in T1 stage while Jagged1 expression was not statistically different between localized and metastatic tumors of all stages. The average size of metastatic tumors was significantly larger than localized tumors in T1 stage ccRCC and the elevated expression of Notch1 was significantly positive correlated with the tumor diameter. The functional significance of Notch signaling was studied by transfection of 786-O, Caki-1 and HKC cell lines with full-length expression plasmids of Notch1 and Jagged1

    Detection of the Diffuse Supernova Neutrino Background with JUNO

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    As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
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