检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

对流扩散特征值问题的自适应间断有限元方法

数学杂志 2023年第6期43卷 515-528页

作者：段丽梅陈兴龙韩家宇贵州师范大学数学科学学院贵州贵阳550025

本文研究了对流扩散特征值问题的间断有限元方法.对流扩散方程作为偏微分方程一个重要的分支,源于环境科学、流体力学、空气动力学等诸多实际物理背景中,由于对流扩散方程的解很难通过解析的方法得到,所以探索对流扩散方程的数值方法具... 详细信息

本文研究了对流扩散特征值问题的间断有限元方法.对流扩散方程作为偏微分方程一个重要的分支,源于环境科学、流体力学、空气动力学等诸多实际物理背景中,由于对流扩散方程的解很难通过解析的方法得到,所以探索对流扩散方程的数值方法具有重要的价值.对流扩散特征值问题的数值方法是当前计算数学界的热点.该研究的困难之处在于该问题的非对称性和对流项导致的边界层效应.本文利用间断有限元法方法研究对流扩散特征值问题,获得了该方法的完整的后验误差估计结果,并进行了自适应有限元计算.数值实验结合理论分析表明我们的方法达到了最优收敛阶.

关键词：对流扩散特征值间断有限元方法后验误差自适应计算

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

干细胞的趋电性迁移及机制

中国组织工程研究 2025年第23期29卷 4984-4992页

作者：韩芳舒晴贾绍辉田峻武汉体育学院运动医学院湖北省武汉市430079 武汉大学中南医院骨科康复科湖北省武汉市430071

背景:随着对干细胞技术研究的深入,如何使其准确归巢成为临床应用中的一大难题。除药物和趋化因子等信号的诱导外,电场也被广泛应用于指导干细胞的定向迁移,并可增强其迁移速度和定向性。目的:旨在分析总结电场对干细胞迁移特性的影响,... 详细信息

背景:随着对干细胞技术研究的深入,如何使其准确归巢成为临床应用中的一大难题。除药物和趋化因子等信号的诱导外,电场也被广泛应用于指导干细胞的定向迁移,并可增强其迁移速度和定向性。目的:旨在分析总结电场对干细胞迁移特性的影响,同时综述可能的作用机制。方法:通过检索Pub Med和中国知网数据库,收集截至2024年3月的相关文献,英文检索词:“stem cells,direct current electric field,pulsed electric field,migration,electric field device,mechanism”;中文检索词:“干细胞,直流电场,脉冲电场,迁移,电场装置,机制”。排除不能获取全文和与主题无关的文献。结果与结论:根据筛选要求共纳入58篇文献,包括中文文献15篇及英文文献43篇。文献以脂肪间充质干细胞、骨髓间充质干细胞、神经干细胞、表皮干细胞、人胚胎干细胞和人诱导性多功能干细胞为研究对象,在迁移装置中研究电场的不同参数对上述干细胞迁移的影响及其机制。(1)电场作为一种简单、无创且稳定的干预方式在指导干细胞定向迁移的过程中起着积极作用;(2)不同类型的干细胞发生趋电性迁移的方向不同,同时大部分干细胞的迁移速度和定向性是随着电场强度增加而增加的;(3)不同的电场装置在观测干细胞迁移时的侧重点不同,可根据实验目的而择优选择相关装置;(4)不同干细胞趋电性迁移的机制不完全相同,多数干细胞迁移过程中有MAPK通路、ROCK活化以及PI3K功能的参与,同时还有其他蛋白质复合物与信号通路参与调控该过程;(5)除电场参数不同之外,细胞本身的衰老情况和培养环境也会对趋电性迁移的结果产生影响。总而言之,电场作为一种影响干细胞迁移特性的重要信号,与其他新兴材料结合在组织工程应用中展现出了一定的潜力,有望在指导干细胞归巢方面发挥更加重要的作用,促进骨组织再生和修复以及神经系统、自身免疫系统以及肿瘤等疾病的研究取得更大的突破。

关键词：干细胞电场趋电性迁移机制归巢效应物理因子电场装置细胞衰老培养环境

老年MSM非固定性伴性行为现状及影响因素分析

在线全文

学校读者我要写书评

暂无评论

现代预防医学 2020年第17期47卷 3189-3192页

作者：唐程梦崔帅杨洪斌杨诗凡余彬黄玉玲刘巧兰韩佳禹杨淑娟四川大学华西公共卫生学院/四川大学华西第四医院四川德阳同道健康互助家园 3. 郫都区绢绒健康互助家园 4. 四川省疾病预防控制中心

目的了解50岁及以上老年男男性行为者（MSM,men who have sex with men）与非固定性伴性行为现状,探讨发生高危性行为的影响因素。方法采用滚雪球方法招募50岁及以上男男性行为者作为调查对象,通过问卷调查收集社会人口学特征和性行为... 详细信息

目的了解50岁及以上老年男男性行为者（MSM,men who have sex with men）与非固定性伴性行为现状,探讨发生高危性行为的影响因素。方法采用滚雪球方法招募50岁及以上男男性行为者作为调查对象,通过问卷调查收集社会人口学特征和性行为特征资料。采用X;检验和logistic回归进行统计学分析。结果调查对象中63.0%的老年MSM有非固定性伴,其中78.1%在最近6个月有2个及以上非固定性伴,安全套坚持使用率为38.0%。Logistic回归分析发现初中文化程度（OR=0.317,95%CI:0.112～0.894）是坚持安全套使用的保护因素,已婚且与配偶居住（OR=12.056,95%CI:1.542～94.288）和外出工作超过3年（3～5年组OR=10.779,95%CI:2.786～41.707;6～10年组OR=16.460,95%CI:3.288～82.408;超过10年组OR=3.490,95%CI:1.168～10.427）是坚持安全套使用的危险因素。结论老年MSM普遍存在多性伴性行为,安全套使用情况不理想。制定行为干预措施时应充分考虑老年MSM的社会人口学特征,重点关注文化程度较低、有婚姻经历、有外出工作经历者。

关键词：老年男男性行为非固定性伴影响因素

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

黄条鰤不同组织碳稳定同位素的转化率与分馏

水产学杂志 2017年第6期30卷 34-40页

作者：韩羽嘉田甲申李多慧王震鹿志创木云雷大连海洋大学辽宁大连116023 辽宁省海洋水产科学研究院辽宁省海洋生物资源和生态学重点实验室辽宁大连116023 大连市水产研究所辽宁大连116019

在水温18.79~22.15℃的实验室条件下,给体质量(34.2±1.8)g的黄条鰤Seriola aureovittata投喂已知碳源的冰鲜玉筋鱼Ammodytes personatus肌肉,研究黄条鰤不同组织碳稳定同位素的转化率差异及分馏系数,以探讨组织生长和代谢对不同组织碳... 详细信息

在水温18.79~22.15℃的实验室条件下,给体质量(34.2±1.8)g的黄条鰤Seriola aureovittata投喂已知碳源的冰鲜玉筋鱼Ammodytes personatus肌肉,研究黄条鰤不同组织碳稳定同位素的转化率差异及分馏系数,以探讨组织生长和代谢对不同组织碳稳定同位素转化的相对贡献。结果表明,黄条鰤各组织碳稳定同位素半衰期从小到大依次为肝脏(3.2d)、肠(3.4d)、鳃(3.6d)、心脏(5.5d)、肌肉(6.4d),各组织与饵料间的碳稳定同位素富集系数(△δ^(13)C)从小到大依次为肝(0.15‰)、肠(0.48‰)、心脏(0.98‰)、鳃(1.02‰)、肌肉(1.08‰)。代谢作用对肝脏和肠组织的碳稳定同位素转化率的贡献占主导地位(>60%),生长作用对其贡献相对较小。肝脏和肠组织可反映黄条鰤短期内的摄食特征,而肌肉组织则可反映较长时间的摄食特征。本研究结果可丰富黄条鰤基础生物学内容,为不同时间尺度的稳定同位素研究取样和工厂化养殖中的营养强化、饵料选择等提供参考。

关键词：黄条鲕碳稳定同位素同位素分馏转化率

Effects of different courses of moxibustion treatment on intestinal flora and inflammation of a rat model of knee osteoarthritis

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Medicine 2022年第2期20卷 173-181页

作者： Ye-juan jia Tian-yu Li Peng han yu Chen Li-jia Pan Chun-sheng jia School of Acupuncture Moxibustion and TuinaHebei University of Chinese MedicineShijiazhuang 050200Hebei ProvinceChina

Objective:This study was done to determine the effects of different courses of moxibustion on a rat knee osteoarthritis(KOA)model,and explore the dose–effect relationship of moxibustion on KOA from the perspectives of intestinal flora and inflammatory ***:Wistar rats were randomly divided into five groups:normal,model,moxibustion for 2 weeks,moxibustion for 4 weeks and moxibustion for 6 weeks groups(n=5 each group).A KOA rat model was induced by monosodium iodoacetate,and moxibustion intervention was performed at the acupoints“Dubi”(ST35)and“Zusanli”(ST36),once every other *** changes in the cartilage of rat knee joints were assessed after intervention,and fecal samples were subjected to 16 S r RNA high-throughput sequencing for microbial diversity ***:Damage to the knee articular cartilage was obvious in the model group,which also had increased levels of pro-inflammatory factors,decreased levels of anti-inflammatory factors,and intestinal flora disorders with decreased *** degree of cartilage damage in the 4 and 6 weeks of moxibustion groups was significantly improved compared with the model *** 4 and 6 weeks of moxibustion groups also demonstrated reduced levels of interleukin-1βand tumor necrosis factor-a and increased levels of interleukin-10(P<0.05).Both the abundance and diversity of the intestinal flora were increased,approaching those of the normal *** of probiotics Eubacterium coprostanoligenes group and Ruminococcaceae UCG-014 increased,while that of the pathogenic bacteria Lachnospiraceae NK4 A136 group decreased(P<0.05).Although the abundance of Lachnospiraceae NK4 A136 group decreased in the 2 weeks of moxibustion group compared with the model group(P<0.05),there was no statistically significant difference in serum inflammatory factors,flora species diversity or degree of pathological damage compared with the model ***:Moxibustion treatment led to significant improvements in t

关键词： Knee osteoarthritis Different courses Moxibustion treatment Intestinal flora Inflammatory cytokines

Flow-Induced Vibration Fatigue Damage of A Pair of Flexible Cylinders in A Staggered Array

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2021年第6期35卷 878-890页

作者： XU Wan-hai LI yu-han jia Kun LAI jiang State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China Nuclear Power Institute of China Chengdu 610041China

Flow-induced vibration(FIV)of a group of long,flexible cylinders involves a complex interaction between fluid and *** a substantial number of studies have been devoted to assessing FIV response behaviours,fatigue damage features of staggered flexible cylinders are not fully ***,the wake-induced flutter constitutes an intricate hydrodynamic behaviour that frequently occurs when one cylinder is in the vicinity of another ***,existing studies on the fatigue damage caused by wake-induced flutter are incapable of achieving better *** paper,therefore,estimates the FIV fatigue damage of two staggered flexible cylinders with an aspect ratio of 350 and a mass ratio of 1.90 based on normal S−N curves according to Det Norske Veritas(DNV)*** staggered cases(cross-flow spacing ratios of 2.0,3.0,4.0,and 6.0 and in-line spacing ratios of 4.0,6.0,and 8.0)are discussed for comparison,and fatigue damage caused by wake-induced flutter is thoroughly *** damage results indicate that the variation of the cross-flow(CF)spacing ratio has a greater influence than that of the in-line(IL)spacing ratio on the CF fatigue damage of the upstream *** IL fatigue damages of the upstream cylinder are observed when reduced velocity V_(r)≥15.03 due to the wake flow patterns with different IL spacing ***,wake interference,especially wake-induced flutter,predominates the fatigue damage characteristics of the downstream *** V_(r)=8.77−11.27,wake-induced flutter enhances the IL fatigue damage of the downstream cylinder and slightly affects that of the upstream ***,wake-induced flutter causes considerable IL fatigue damage disparity between the two staggered cylinders by suppressing the IL fatigue damage of the upstream cylinder when V_(r)≥20.04.

关键词： flow-induced vibration fatigue damage flexible cylinder staggered arrangement wake-induced flutter

Cerebral fat embolism following autologous fat injection in facial reconstruction:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2025年第2期13卷 50-58页

作者： Xiu-Ying Chen Fa Shen Chang Cheng yu-han Wang Wen-Chao Cheng De-Zhi yuan Wen Huang Department of Neurology Chongqing Emergency Medical CenterChongqing University Central HospitalChongqing 400000China Department of Neurology Xinqiao HospitalThe Army Medical University(Third Military Medical University)Chongqing 400000China

BACKGROUND Autologous fat injection in facial reconstruction is a common cosmetic *** cerebral fat embolism(CFE)as a complication is rare,it carries serious health *** SUMMARY We present a case of a 29-year-old female patient who developed acute CFE following facial fat filling *** the surgery,the patient experienced symptoms including headache,nausea,vomiting,and difficulty breathing,which was followed by neurological symptoms such as slurred speech and left-sided *** physical examination and auxiliary investigations,including blood tests,head and neck computed tomography angiography,and cranial magnetic resonance diffusion-weighted imaging,were performed upon *** clinical diagnosis was acute cerebral embolism following facial fat filling *** included measures to improve cerebral circulation,dehydration for intracranial pressure reduction,nutritional support,and rehabilitation therapy for left limb *** patient showed a significant improvement in symptoms after 2 weeks of *** recovered left limb muscle strength to grade 5,had clear speech,and experienced complete relief of *** Our case highlights the potential occurrence of severe complications in patients undergoing fat injection in facial *** prevent these complications,plastic surgeons should enhance their professional knowledge and skills.

关键词： Cerebral fat embolism Mechanical thrombectomy Thrombolysis Steroid therapy Symptomatic treatment Case report

Climatic impacts induced by winter wheat irrigation over North China simulated by the nonhydrostatic RegCM4.7

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第2期15卷 197-210页

作者： jia WU Zhen-yu han Xue-Jie GAO Zheng-jia LIU National Climate Centre China Meteorological AdministrationBeijing 100081China Key Laboratory for Climate Studies China Meteorological AdministrationBeijing 100081China Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China

Quantification of the impact of winter wheat irrigation on the climate and the occurrence of extreme climatic events over North China is crucial for regional adaptation *** related studies mainly focused on the impact on surface processes;however,few focused on the effects of extreme events using high-resolution nonhydrostatic regional climate ***,the 9-km-resolution nonhydrostatic RegCM4.7 was coupled with a crop irrigation scheme and an updated winter wheat irrigation dataset to better simulate irrigation *** experiments were conducted with and without winter wheat irrigation to isolate the effects of *** showed that irrigation simulation reduces the model biases in temperature,precipitation,latent heat flux,soil moisture,sensitive heat flux,and top-layer soil ***,it also reduces the bias and increases the correlation with observations obtained in irrigated areas,especially in summer,indicating better representation of irrigation *** wheat irrigation tends to cause substantial cooling of the local surface maximum,minimum,and mean air temperatures(by-1.68,-0.34,and-0.79℃,respectively)over irrigated areas of North China,with the largest changes observed in relation to maximum ***,precipitation is found to increase during spring and summer,which is strongly related to water vapor transport in the lower levels of the *** analyses indicated that the number of annual mean hot days decrease(-13.9 d),whereas the number of both comfort days(+10.2 d)and rainy days(days with total precipitation greater than 1 mm:+6.6 d)increase over irrigated areas,demonstrating beneficial feedback to human perception and ***,although the heat wave risk increases(number of annual mean heat wave days:+5.8 d),the impact is limited to small areas within irrigated ***,no notable change was found in terms of heavy rainfall events and precipitation intensity

关键词： Nonhydrostatic regional climate model Irrigation effect Extreme events North China

四川省美沙酮维持治疗患者脱失现状及其影响因素

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

现代预防医学 2019年第23期46卷 4363-4367页

作者：董佩杰韩佳禹杨淑娟余彬杨诗凡龚毅周英廖蕊唐程梦四川大学华西公共卫生学院/四川大学华西第四医院四川省疾病预防控制中心成都市武侯区第二人民医院

目的了解四川省美沙酮维持治疗患者的脱失现状,分析患者脱失的影响因素,为降低美沙酮维持治疗的脱失率提供理论依据。方法多阶段整群随机法,通过面对面问卷调查,对四川省5家美沙酮美沙酮维持治疗门诊点的581名海洛因成瘾者的脱失情况进... 详细信息

目的了解四川省美沙酮维持治疗患者的脱失现状,分析患者脱失的影响因素,为降低美沙酮维持治疗的脱失率提供理论依据。方法多阶段整群随机法,通过面对面问卷调查,对四川省5家美沙酮美沙酮维持治疗门诊点的581名海洛因成瘾者的脱失情况进行调查,使用卡方检验和logistic回归分析,探究美沙酮患者脱失的影响因素。结果 logistic回归分析发现,调查对象过去6个月的脱失情况与其对美沙酮维持治疗的认知有关(P50 ml的患者不易发生脱失(OR=0.568,95%CI:0.333～0.969);与家人现阶段关系非常好或较好的患者不易发生脱失(OR=0.509,95%CI:0.264～0.982)。偷吸海洛因的患者容易发生服药脱失(OR=2.542,95%CI=1.879-4.299)。结论 MMT门诊应对美沙酮患者进行适当的健康教育,普及正确的美沙酮维持治疗知识,帮助恢复其家庭及社会功能、克服毒瘾,减少患者的脱失。

关键词：美沙酮脱失影响因素