2,461 research outputs found

    Performance evaluation of keyword extraction methods and visualization for student online comments

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    Topic keyword extraction (as a typical task in information retrieval) refers to extracting the core keywords from document topics. In an online environment, students often post comments in subject forums. The automatic and accurate extraction of keywords from these comments are beneficial to lecturers (particular when it comes to repeatedly delivered subjects). In this paper, we compare the performance of traditional machine learning algorithms and two deep learning methods in extracting topic keywords from student comments posted in subject forums. For this purpose, we collected student comment data from a period of two years, manually tagging part of the raw data for our experiments. Based on this dataset, we comprehensively compared the five typical algorithms of naïve Bayes, logistic regression, support vector machine, convolutional neural networks, and Long Short-Term Memory with Attention (Att-LSTM). The performances were measured by the four evaluation metrics. We further examined the keywords by visualization. From the results of our experiment and visualization, we conclude that the Att-LSTM method is the best approach for topic keyword extraction from student comments. Further, the results from the algorithms and visualization are symmetry, to some degree. In particular, the extracted topics from the comments posted at the same stages of different teaching sessions are, almost, reflection symmetry

    Heparin-Binding Protein Promotes Acute Lung Injury in Sepsis Mice by Blocking the Aryl Hydrocarbon Receptor Signaling Pathway

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    Kun Ye,1 Xiang Lin,2 Tai-Zhi Chen,2 Long-Hui Wang,2 Sheng-Xing Liu2 1Department of Orthopaedics, Qiantang Campus of Sir Run Run Shaw Hospital, Medical College of Zhejiang University, Hangzhou, Zhejiang, 310018, People’s Republic of China; 2Department of Orthopaedics, The Second Affiliated Hospital of Hainan Medical University, Hainan Medical University, Haikou, Hainan, 570311, People’s Republic of ChinaCorrespondence: Sheng-Xing Liu, Email [email protected]: This study aimed to explore the therapeutic effect and potential mechanism of heparin-binding protein (HBP) reduction on sepsis-related acute lung injury.Methods: We utilized a murine model of sepsis-induced by intraperitoneal injection of lipopolysaccharides (LPS) in C57BL/6J mice divided into four groups: Control, LPS, Anti-HBP, and ceftriaxone (CEF). Following sepsis induction, Anti-HBP or CEF treatments were administered, and survival rates were monitored for 48 h. We then used reverse-transcription quantitative PCR to analyze the expression levels of HBP in lung tissues, immunohistochemistry for protein localization, and Western blotting for protein quantification. Pulmonary inflammation was assessed using enzyme-linked immunosorbent assays of proinflammatory cytokines (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, and interferon-γ). The activation state of the aryl hydrocarbon receptor (AhR) signaling pathway was determined via Western blotting, evaluating both cytoplasmic and nuclear localization of AhR and the expression of cytochrome P450 1A1 protein by its target gene.Results: Anti-HBP specifically reduced HBP levels. The survival rate of mice in the Anti-HBP and CEF groups was much higher than that in the LPS group. The severity of lung injury and pulmonary inflammatory response in the Anti-HBP and CEF groups was significantly lower than that in the LPS group. AhR signaling pathway activation was observed in the Anti-HBP and CEF groups. Additionally, there was no significant difference in the above indices between the Anti-HBP and CEF groups.Conclusion: HBP downregulation in lung tissues significantly improved LPS-induced lung injury and the pulmonary inflammatory response, thereby prolonging the survival of sepsis mice, suggesting activation of the AhR signaling pathway. Moreover, the effect of lowering the HBP level was equivalent to that of the classical antibiotic CEF.Trial Registration: Not applicable.Keywords: sepsis, acute lung injury, heparin-binding protein, aryl hydrocarbon receptor signaling pathwa

    Seroprevalence of Mycoplasma bovis infection in dairy cows in subtropical southern China

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    The seroprevalence of Mycoplasma bovis infection in dairy cows in Guangxi Zhuang Autonomous Region (GZAR) in subtropical southern China was surveyed between June 2009 and March 2010. A total of 455 serum samples of dairy cows were collected from 6 districts in 4 different cities, and examined for M. bovis antibodies with the indirect enzyme-linked immunosorbent assay (ELISA) using a commercially available kit. The overall seroprevalence of M. bovis infection in dairy cows was 7.69% (35/455). Three year-old dairy cows had the highest seroprevalence (15.0%), followed by dairy cows of 4 year-old (11.1%). Dairy cows with the history of 5 pregnancies had the highest seroprevalence (33.3%). However, no statistically significant association was found between M. bovis infection and age or number of pregnancies (p > 0.05). All the aborting dairy cows were negative for M. bovis antibodies, suggesting that bovine abortion may have no association with M. bovis infection in GZAR. These results indicate that M. bovis infection in dairy cows was widespread in GZAR, and integrated strategies and measures should be performed to control and prevent M. bovis infection and disease outbreak.Key words: Mycoplasma bovis, seroprevalence, dairy cows, Guangxi Zhuang Autonomous Region (GZAR), China, enzyme-linked immunosorbent assay (ELISA)

    BRCA1 function in T lymphocytes: a cellular specificity of a different kind

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    Recent work by Mak et al demonstrates that mice carrying a T-cell-specific disruption of the brca1 gene display markedly impaired T-lymphocyte development and proliferation in the absence of any increased tendency for the formation of tumors. Interestingly, the extent of these defects was found to be highly dependent on cellular context. Contrasting the rather broad tissue expression pattern of brca1 against its exquisitely selective etiologic role in cancers of the breast and ovary, many of us are left to ponder - where is the specificity

    Mental disorder symptoms during the COVID-19 pandemic in Latin America - a systematic review and meta-analysis.

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    AIMS: There is a lack of evidence related to the prevalence of mental health symptoms as well as their heterogeneities during the coronavirus disease 2019 (COVID-19) pandemic in Latin America, a large area spanning the equator. The current study aims to provide meta-analytical evidence on mental health symptoms during COVID-19 among frontline healthcare workers, general healthcare workers, the general population and university students in Latin America. METHODS: Bibliographical databases, such as PubMed, Embase, Web of Science, PsycINFO and medRxiv, were systematically searched to identify pertinent studies up to August 13, 2021. Two coders performed the screening using predefined eligibility criteria. Studies were assigned quality scores using the Mixed Methods Appraisal Tool. The double data extraction method was used to minimise data entry errors. RESULTS: A total of 62 studies with 196 950 participants in Latin America were identified. The pooled prevalence of anxiety, depression, distress and insomnia was 35%, 35%, 32% and 35%, respectively. There was a higher prevalence of mental health symptoms in South America compared to Central America (36% v. 28%, p < 0.001), in countries speaking Portuguese (40%) v. Spanish (30%). The pooled prevalence of mental health symptoms in the general population, general healthcare workers, frontline healthcare workers and students in Latin America was 37%, 34%, 33% and 45%, respectively. CONCLUSIONS: The high yet heterogenous level of prevalence of mental health symptoms emphasises the need for appropriate identification of psychological interventions in Latin America

    Characterizations of some N-substituted-salicylhydrazide in mixtures by NMR diffusion ordered spectroscopy

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    Several novel N-substituted-salicylhydrazide ligands, most of which are difficult to be purified or recrystallized so that their chemical configurations can not be confirmed by conventional NMR and/or X-ray diffraction techniques, were synthesized in this experiment, and their chemical configurations in mixture were analyzed and characterized by 2D NMR diffusion ordered spectroscopy (DOSY), a labor-saving virtual separation based on diffusion properties, together with several routine NMR techniques

    AMS Radiocarbon Dating of Tianma-Qucun Site in Shanxi, China

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    Tianma-Qucun is the biggest site of Western Zhou Dynasty discovered in Shanxi Province, China. It has been recognized as the early capital of Jin, a vassal state of Western Zhou. The territories were granted to the first Marquis of Jin with the title in the early days of Western Zhou. Bone sample series from the site were radiocarbon-dated by accelerator mass spectrometry (AMS) and calibrated with the Oxford calibration program OxCal 3.5. Bayesian analysis of the calibrated ages shows that the earliest residents of the Western Zhou came to Tianma-Qucun area in 1020-940 BC and the lower boundary of the Western Zhou is 796-754 BC, which corresponds well to the historical record 770 BC.Geochemistry &amp; GeophysicsSCI(E)CPCI-S(ISTP)

    Progress and Prospects of Emerging Potassium–Sulfur Batteries

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    The potassium–sulfur battery (K–S battery) as an innovative battery technology is a promising candidate for large-scale applications, due to its high energy density and the low cost of both K and S. The development of the K–S technology is, however, inhibited by its low reversible capacity and the safety issues related to the K metal anode. Here, the review starts by discussing the mechanism of the redox reactions for the K–S batteries and emphasizes the challenges for this battery system based on its current research status. Furthermore, the current improvement strategies for the K–S system in terms of the sulfur cathode, electrolyte, separator, and K metal anode are summarized. Finally, future perspectives on the development of the K–S system are proposed
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