Based on flux-based formulation, a nodeless variable element method is developed to analyze two-dimensional steady-state and transient heat transfer problems. The nodeless variable element employs quadratic interpolat...Based on flux-based formulation, a nodeless variable element method is developed to analyze two-dimensional steady-state and transient heat transfer problems. The nodeless variable element employs quadratic interpolation functions to provide higher solution accuracy without necessity to actually generate additional nodes. The flux-based formulation is applied to reduce the complexity in deriving the finite element equations as compared to the conventional finite element method, The solution accuracy is further improved by implementing an adaptive meshing technique to generaie finite element mesh that can adapt and move along corresponding to the solution behavior. The technique generates small elements in the regions of steep solution gradients to provide accurate solution, and meanwhile it generates larger elements in the other regions where the solution gradients are slight to reduce the computational time and the computer memory. The effectiveness of the combined procedure is demonstrated by heat transfer problems that have exact solutions. These problems tire： （a） a steady-state heat conduction analysis in a square plate subjected to a highly localized surface heating, and （b） a transient heat conduction analysis in a long plate subjected to moving heat source.展开更多
The aim of this study was to analyze the majority of publications using effective methods to speed up orthodontic treatment and determine which publications carry high evidence-based value. The literature published in...The aim of this study was to analyze the majority of publications using effective methods to speed up orthodontic treatment and determine which publications carry high evidence-based value. The literature published in Pubmed from 1984 to 2013 was reviewed, in addition to well-known reports that were not classified under this database. To facilitate evidence-based decision making, guidelines such as the Consolidation Standards of Reporting Trials, Preferred Reporting items for systematic Reviews and Meta-analyses, and Transparent Reporting of Evaluations with Nonrandomized Designs check list were used. The studies were initially divided into three groups: local application of cell mediators, physical stimuli, and techniques that took advantage of the regional acceleration phenomena. The articles were classified according to their level of evidence using an alternative method for orthodontic scientific article classification. 1a: Systematic Reviews(SR) of randomized clinical trials(RCTs), 1b: Individual RCT, 2a: SR of cohort studies, 2b: Individual cohort study, controlled clinical trials and low quality RCT, 3a:SR of case-control studies, 3b: Individual case-control study, low quality cohort study and short time following split mouth designs. 4: Case-series, low quality casecontrol study and non-systematic review, and 5: Expert opinion. The highest level of evidence for each group was:(1) local application of cell mediators: the highest level of evidence corresponds to a 3B level in Prostaglandins and Vitamin D;(2) physical stimuli: vibratory forces and low level laser irradiation have evidence level 2b, Electrical current is classified as 3b evidencebased level, Pulsed Electromagnetic Field is placed on the 4th level on the evidence scale; and(3) regional acceleration phenomena related techniques: for corticotomy the majority of the reports belong to level 4. Piezocision, dentoalveolar distraction, alveocentesis, monocortical tooth dislocation and ligament distraction technique, only had case series or single report cases(4th level of evidence). Surgery first and periodontal distraction have 1 study at level 2b and corticision one report at level 5. Multiple orthodontic acceleration reports on humans were identified by an alternative evidence level scale, which is a simple and accurate way of determining which techniques are better and have a higher rate of effectiveness. The highest level of evidence for a specific procedure to accelerate orthodontic dental movement up to October 2013 was surgery first followed by low level laser application, corticotomy and periodontal distraction located on level 2, recommendation grade b from this proposed scientific evidencebased scale.展开更多
Previous studies have demonstrated that advanced Alzheimer＇s disease（AD）patients have deficiency of eye movements.However,there have been no reports on eye movement in the early stages of AD.The aim of this study w...Previous studies have demonstrated that advanced Alzheimer＇s disease（AD）patients have deficiency of eye movements.However,there have been no reports on eye movement in the early stages of AD.The aim of this study was to evaluate pursuit ocular movements（POM）provided by a vision-based non-intrusive eye tracker in patients with early AD.POM values were significantly lower in AD patients than in normal controls（P 〈 0.01）.In AD patients,POM values were not closely correlated with the Mini-Mental State Examination scores（P = 0.3）.There was no significant difference in POM values among patients treated with or without anticholinesterase therapy.We used a vision-based method,for non-intrusive eye tracking,which can be proposed as a possible tool for supporting the diagnosis of early AD.展开更多
车车通信列车运行控制系统中移动授权的生成对城市轨道交通运营效率有着较大的影响。通过分析车车通信列车运行控制系统中移动授权的生成过程及性能,建立基于有色Petri网(colored Petri net,CPN)的车车通信移动授权信息交互的模型,进行...车车通信列车运行控制系统中移动授权的生成对城市轨道交通运营效率有着较大的影响。通过分析车车通信列车运行控制系统中移动授权的生成过程及性能,建立基于有色Petri网(colored Petri net,CPN)的车车通信移动授权信息交互的模型,进行性能分析。研究移动授权生成过程中端对端通信传输时延的延时概率,根据不同信道质量下统计传输时延的平均值,计算移动授权完成的成功率。分析结果表明,基于车车通信的列车运行控制系统移动授权的生成过程,符合地铁长期演进(long term evolution for metro,LTE-M)系统端到端延时时间不大于150 ms的概率不小于98%,时延随着信道质量的下降而增加。展开更多
目的对踝关节运动在防治深静脉血栓(DVT)中的作用进行系统性评估,为临床实践提供参考依据。方法通过计算机搜索Cochrane Library、Web of Science、PubMed、CINAHL、Embase、中国知网、万方医学网、维普资讯中文期刊服务平台、中国生物...目的对踝关节运动在防治深静脉血栓(DVT)中的作用进行系统性评估,为临床实践提供参考依据。方法通过计算机搜索Cochrane Library、Web of Science、PubMed、CINAHL、Embase、中国知网、万方医学网、维普资讯中文期刊服务平台、中国生物医学文献服务系统等数据库中关于踝关节运动预防下肢DVT的原始文献,检索时限为建库至2023年7月。由2名研究人员根据纳入/排除标准独立对文献进行筛选,提取相关数据,并对文献质量进行评价,使用Stata16软件进行meta分析。结果共纳入文献14篇,包括1572名患者。踝关节运动能降低骨科患者术后DVT发生率、增加最大静脉容量及最大静脉流出量、减小大腿周径,差异均有统计学意义(风险比/均数差0.26、1.14、0.94、-2.18,95%可信区间0.16~0.42、0.60~1.67、0.43~1.44、-3.31~-1.05,P<0.001);减小小腿周径、降低术后不良事件发生率比较,差异均无统计学意义(均数差/风险比-2.27、0.76,95%可信区间-5.12~0.57、0.31~1.85,P=0.117、0.543)。结论踝关节运动可有效降低骨科患者术后DVT发生率,同时可改善患者血流动力学状况和减小大腿周径,但对减小小腿周径、降低不良反应的效果不明显。展开更多
文摘Based on flux-based formulation, a nodeless variable element method is developed to analyze two-dimensional steady-state and transient heat transfer problems. The nodeless variable element employs quadratic interpolation functions to provide higher solution accuracy without necessity to actually generate additional nodes. The flux-based formulation is applied to reduce the complexity in deriving the finite element equations as compared to the conventional finite element method, The solution accuracy is further improved by implementing an adaptive meshing technique to generaie finite element mesh that can adapt and move along corresponding to the solution behavior. The technique generates small elements in the regions of steep solution gradients to provide accurate solution, and meanwhile it generates larger elements in the other regions where the solution gradients are slight to reduce the computational time and the computer memory. The effectiveness of the combined procedure is demonstrated by heat transfer problems that have exact solutions. These problems tire： （a） a steady-state heat conduction analysis in a square plate subjected to a highly localized surface heating, and （b） a transient heat conduction analysis in a long plate subjected to moving heat source.
文摘The aim of this study was to analyze the majority of publications using effective methods to speed up orthodontic treatment and determine which publications carry high evidence-based value. The literature published in Pubmed from 1984 to 2013 was reviewed, in addition to well-known reports that were not classified under this database. To facilitate evidence-based decision making, guidelines such as the Consolidation Standards of Reporting Trials, Preferred Reporting items for systematic Reviews and Meta-analyses, and Transparent Reporting of Evaluations with Nonrandomized Designs check list were used. The studies were initially divided into three groups: local application of cell mediators, physical stimuli, and techniques that took advantage of the regional acceleration phenomena. The articles were classified according to their level of evidence using an alternative method for orthodontic scientific article classification. 1a: Systematic Reviews(SR) of randomized clinical trials(RCTs), 1b: Individual RCT, 2a: SR of cohort studies, 2b: Individual cohort study, controlled clinical trials and low quality RCT, 3a:SR of case-control studies, 3b: Individual case-control study, low quality cohort study and short time following split mouth designs. 4: Case-series, low quality casecontrol study and non-systematic review, and 5: Expert opinion. The highest level of evidence for each group was:(1) local application of cell mediators: the highest level of evidence corresponds to a 3B level in Prostaglandins and Vitamin D;(2) physical stimuli: vibratory forces and low level laser irradiation have evidence level 2b, Electrical current is classified as 3b evidencebased level, Pulsed Electromagnetic Field is placed on the 4th level on the evidence scale; and(3) regional acceleration phenomena related techniques: for corticotomy the majority of the reports belong to level 4. Piezocision, dentoalveolar distraction, alveocentesis, monocortical tooth dislocation and ligament distraction technique, only had case series or single report cases(4th level of evidence). Surgery first and periodontal distraction have 1 study at level 2b and corticision one report at level 5. Multiple orthodontic acceleration reports on humans were identified by an alternative evidence level scale, which is a simple and accurate way of determining which techniques are better and have a higher rate of effectiveness. The highest level of evidence for a specific procedure to accelerate orthodontic dental movement up to October 2013 was surgery first followed by low level laser application, corticotomy and periodontal distraction located on level 2, recommendation grade b from this proposed scientific evidencebased scale.
文摘Previous studies have demonstrated that advanced Alzheimer＇s disease（AD）patients have deficiency of eye movements.However,there have been no reports on eye movement in the early stages of AD.The aim of this study was to evaluate pursuit ocular movements（POM）provided by a vision-based non-intrusive eye tracker in patients with early AD.POM values were significantly lower in AD patients than in normal controls（P 〈 0.01）.In AD patients,POM values were not closely correlated with the Mini-Mental State Examination scores（P = 0.3）.There was no significant difference in POM values among patients treated with or without anticholinesterase therapy.We used a vision-based method,for non-intrusive eye tracking,which can be proposed as a possible tool for supporting the diagnosis of early AD.
文摘车车通信列车运行控制系统中移动授权的生成对城市轨道交通运营效率有着较大的影响。通过分析车车通信列车运行控制系统中移动授权的生成过程及性能,建立基于有色Petri网(colored Petri net,CPN)的车车通信移动授权信息交互的模型,进行性能分析。研究移动授权生成过程中端对端通信传输时延的延时概率,根据不同信道质量下统计传输时延的平均值,计算移动授权完成的成功率。分析结果表明,基于车车通信的列车运行控制系统移动授权的生成过程,符合地铁长期演进(long term evolution for metro,LTE-M)系统端到端延时时间不大于150 ms的概率不小于98%,时延随着信道质量的下降而增加。
文摘目的对踝关节运动在防治深静脉血栓(DVT)中的作用进行系统性评估,为临床实践提供参考依据。方法通过计算机搜索Cochrane Library、Web of Science、PubMed、CINAHL、Embase、中国知网、万方医学网、维普资讯中文期刊服务平台、中国生物医学文献服务系统等数据库中关于踝关节运动预防下肢DVT的原始文献,检索时限为建库至2023年7月。由2名研究人员根据纳入/排除标准独立对文献进行筛选,提取相关数据,并对文献质量进行评价,使用Stata16软件进行meta分析。结果共纳入文献14篇,包括1572名患者。踝关节运动能降低骨科患者术后DVT发生率、增加最大静脉容量及最大静脉流出量、减小大腿周径,差异均有统计学意义(风险比/均数差0.26、1.14、0.94、-2.18,95%可信区间0.16~0.42、0.60~1.67、0.43~1.44、-3.31~-1.05,P<0.001);减小小腿周径、降低术后不良事件发生率比较,差异均无统计学意义(均数差/风险比-2.27、0.76,95%可信区间-5.12~0.57、0.31~1.85,P=0.117、0.543)。结论踝关节运动可有效降低骨科患者术后DVT发生率,同时可改善患者血流动力学状况和减小大腿周径,但对减小小腿周径、降低不良反应的效果不明显。
