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101.
The lockdown due to COVID-19 in Italy resulted in the sudden closure of schools, with a shift from traditional teaching to the online one. Through an online questionnaire, this survey explores teachers' experience of online teaching, the level of risk factors (e.g., stress) and protective factors (e.g., locus of control) and their impact on satisfaction levels during the social distancing. One hundred seven high school teachers from Lombardy, an Italian region very affected by the COVID-19 outbreak, participated. Results show that depression and stress are the main predictors of satisfaction levels for online teaching. In addition, coping, locus of control and self-efficacy emerge as important protective factors. Finally, although there is great satisfaction with the online teaching experience, critical elements emerged. This study is relevant because it describes the critical elements of the online teaching experience, and identifies some protective factors and the main risk factors in teachers operating in an area strongly marked by social restrictions imposed by the pandemic. High school teachers emerge as a sub-group of the general population with specific psychological reactions. Considering the results, it is possible to suggest providing high-quality educational support and crisis-psychological oriented services to teachers, and help to maintain the psychological well-being.  相似文献   
102.
微博作为一种被广泛使用的网络平台,其多样的特性满足了人们信息获取、人际交流等多方面的新需求,微博已成为人们日常生活的重要组成部分之一。微博影响力作为微博研究的一个热点,对于优化微博的信息整合、传输,对于深入了解微博发展方向、维护网络内容安全、促进网络发展具有非常重要的理论和实践意义。文章对当前主要的微博影响力评价方法进行了梳理和分析,并提出了针对中国微博的影响力评价模型。  相似文献   
103.
以七水硫酸镁为原料、氨水为沉淀剂、选择适宜的表面活性剂。以样品XRD图中(001)面与(101)面衍射峰的相对强弱为考察指标,通过单因素实验,分别考察了反应温度、恒温反应时间、陈化时间、表面活性剂用量及氨镁摩尔比等因素对氢氧化镁样品XRD图中(001)面与(101)面衍射峰相对强弱的影响。实验结果表明,制备阻燃氩氧化镁较适宜的工艺条件为:反应温度40℃、恒温反应时间40min、陈化时间120min、表面活性剂A体积用量4ml、氨镁摩尔比6:1.  相似文献   
104.
Cancer cachexia (CC) is a multifactorial syndrome in patients with advanced cancer characterized by weight loss via skeletal-muscle and adipose-tissue atrophy, catabolic activity, and systemic inflammation. CC is correlated with functional impairment, reduced therapeutic responsiveness, and poor prognosis, and is a major cause of death in cancer patients. In colorectal cancer (CRC), cachexia affects around 50–61% of patients, but remains overlooked, understudied, and uncured. The mechanisms driving CC are not fully understood but are related, at least in part, to the local and systemic immune response to the tumor. Accumulating evidence demonstrates a significant role of tumor microenvironment (TME) cells (e.g., macrophages, neutrophils, and fibroblasts) in both cancer progression and tumor-induced cachexia, through the production of multiple procachectic factors. The most important role in CRC-associated cachexia is played by pro-inflammatory cytokines, including the tumor necrosis factor α (TNFα), originally known as cachectin, Interleukin (IL)-1, IL-6, and certain chemokines (e.g., IL-8). Heterogeneous CRC cells themselves also produce numerous cytokines (including chemokines), as well as novel factors called “cachexokines”. The tumor microenvironment (TME) contributes to systemic inflammation and increased oxidative stress and fibrosis. This review summarizes the current knowledge on the role of TME cellular components in CRC-associated cachexia, as well as discusses the potential role of selected mediators secreted by colorectal cancer cells in cooperation with tumor-associated immune and non-immune cells of tumor microenvironment in inducing or potentiating cancer cachexia. This knowledge serves to aid the understanding of the mechanisms of this process, as well as prevent its consequences.  相似文献   
105.
为了提高水下设备安装精度与工作效率,基于海上工作经验及查阅国内外相关文献,对水下设备的安装过程进行了研究,其总体过程大致分为5个阶段,即装船固定、提升操作、穿越飞溅区、深水下放、落地坐放;分析了影响水下设备安装过程的主要因素,其中水深主要影响吊放系统和设备在水下的横向偏移;波浪载荷主要应用船舶的动态响应,在设备经历穿越飞溅区阶段时对设备及缆绳造成损伤的风险较大;水下设备自身参数主要影响安装方式和安装船舶的选用。  相似文献   
106.
107.
The aim of the present study was to investigate the influence of a novel volume-stable collagen matrix (vCM) on early wound healing events including cellular migration and adhesion, protein adsorption and release, and the dynamics of the hemostatic system. For this purpose, we utilized transwell migration and crystal violet adhesion assays, ELISAs for quantification of adsorbed and released from the matrix growth factors, and qRT-PCR for quantification of gene expression in cells grown on the matrix. Our results demonstrated that primary human oral fibroblasts, periodontal ligament, and endothelial cells exhibited increased migration toward vCM compared to control cells that migrated in the absence of the matrix. Cellular adhesive properties on vCM were significantly increased compared to controls. Growth factors TGF-β1, PDGF-BB, FGF-2, and GDF-5 were adsorbed on vCM with great efficiency and continuously delivered in the medium after an initial burst release within hours. We observed statistically significant upregulation of genes encoding the antifibrinolytic thrombomodulin, plasminogen activator inhibitor type 1, thrombospondin 1, and thromboplastin, as well as strong downregulation of genes encoding the profibrinolytic tissue plasminogen activator, urokinase-type plasminogen activator, its receptor, and the matrix metalloproteinase 14 in cells grown on vCM. As a general trend, the stimulatory effect of the vCM on the expression of antifibrinolytic genes was synergistically enhanced by TGF-β1, PDGF-BB, or FGF-2, whereas the strong inhibitory effect of the vCM on the expression of profibrinolytic genes was reversed by PDGF-BB, FGF-2, or GDF-5. Taken together, our data strongly support the effect of the novel vCM on fibrin clot stabilization and coagulation/fibrinolysis equilibrium, thus facilitating progression to the next stages of the soft tissue healing process.  相似文献   
108.
Cancer cachexia is a common condition in many cancer patients, particularly those with advanced disease. Cancer cachexia patients are generally less tolerant to chemotherapies and radiotherapies, largely limiting their treatment options. While the search for treatments of this condition are ongoing, standards for the efficacy of treatments have yet to be developed. Current diagnostic criteria for cancer cachexia are primarily based on loss of body mass and muscle function. However, these criteria are rather limiting, and in time, when weight loss is noticeable, it may be too late for treatment. Consequently, biomarkers for cancer cachexia would be valuable adjuncts to current diagnostic criteria, and for assessing potential treatments. Using high throughput methods such as “omics approaches”, a plethora of potential biomarkers have been identified. This article reviews and summarizes current studies of biomarkers for cancer cachexia.  相似文献   
109.
The deposition of copper by cold gas dynamic spraying has attracted much interest in recent years due to the capability to deposit low-porosity oxide-free coatings. However, it is generally found that as-deposited copper has a signicantly greater hardness, and potentially lower ductility, than bulk material. In this article, copper was deposited by cold spraying using helium as the driving gas at both 298 and 523 K. Evidence is presented indicating that the material sprayed at the lower temperature exhibits a lower dislocation density throughout the grain structure than the material sprayed at the higher temperature. The low stacking fault energy of copper restricts recovery during annealing, and thus microstructural changes during annealing only proceed once recrystallization begins. The material sprayed at low temperature (with the low dislocation density) exhibited recrystallization at annealing temperatures as low as 373 K with a corresponding reduction in hardness. However, the copper sprayed with helium at 523 K was resistant to annealing at temperatures up to 473 K where the dislocations in the structure prevented recrystallization. However, at higher temperatures, recrystallization did proceed (with corresponding reductions in hardness). The fracture behavior of the copper that was cold sprayed with helium at 523 K, both in the as-sprayed condition and following annealing, was measured and explained in terms of the annealing mechanisms proposed. The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and HW International Institute of Welding, Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany.  相似文献   
110.
铜冶炼炉渣含有大量的有价金属元素,经过选矿工艺处理后,大部分铜被回收,选出的渣精矿返回熔炼炉,渣尾矿外售至水泥厂,尾矿中有价金属仍存在较大利用价值,在现有工艺流程后增加磁选工艺,磁选后的铁精粉用作炼钢配料,尾矿外售。主要介绍了熔炼渣及尾矿成分,现有工艺尾矿处理方式,新工艺的应用及实践。  相似文献   
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