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101.
利用CT扫描及CAD技术建立腰椎活动节段的有限元模型   总被引:9,自引:0,他引:9  
目的 :探讨腰椎活动节段有限元模型的建立。方法 :选取一正常自愿者L4~L5节段为研究对象 ,通过CT扫描、图像数字化处理及计算机辅助设计建立了腰椎活动节段的有限元模型 ,通过Super SAP有限元分析软件包对模型进行了应力分析。结果 :建立了L4~L5活动节段的有限元模型 ,并分析了生理载荷下腰椎活动节段不同组成部分的应力分布。结论 :为腰椎活动节段有限元模型的建立提供了一种简便、准确的方法 ,为分析和研究该模型在各种情况下的生物力学表现创造了条件  相似文献   
102.
Perceptual Speed and IQ Are Associated Through Common Genetic Factors   总被引:1,自引:0,他引:1  
Individual differences in inspection time explain about 20% of IQ test variance. To determine whether the association between inspection time and IQ is mediated by common genes or by a common environmental factor, inspection time and IQ were assessed in an extended twin design. Data from 688 participants from 271 families were collected as part of a large ongoing project on the genetics of adult brain function and cognition. The sample consisted of a young adult cohort (mean age 26.2 years) and an older adult cohort (mean age 50.4 years). IQ was assessed with the Dutch version of the WAIS-3R. Inspection time was measured in the so-called -paradigm, in which a subject is asked to decide which leg of the -figure is longest at varying display times of the -figure. The number of correct inspections per second (i.e., the reciprocal of inspection time) was used to index perceptual speed. For Verbal IQ and Performance IQ, heritabilities were 85% and 69%, respectively. For perceptual speed, 46% of the total variance was explained by genetic variance. No differences in heritability estimates across age cohorts or sexes were found. Across the whole sample, a significant phenotypic correlation was found between perceptual speed and Verbal IQ (0.19) and between perceptual speed and Performance IQ (0.27). These correlations were entirely due to a common genetic factor that accounted for 10% of the genetic variance in verbal IQ and for 22% of the genetic variance in performance IQ. This factor is hypothesized to reflect the influence of genetic factors that determine axonal myelination in the central nervous system.  相似文献   
103.
The mortality experience of a large refinery cohort (1937-1978) was examined by dividing it into three subcohorts according to hire dates: those hired before 1940, those hired during the period 1940-1945, and those hired after 1945. These three periods are approximately equivalent to before, during, and after World War II and span a total hiring period of more than 75 years. The results showed that a substantial portion of the cohort (3,330 or 27%) had been recruited during 1940-1945, and they contributed 980 or 28% of the total deaths. However, their mortality experience was quite different from the rest. A series of significant increases were seen among the external causes for accidents, suicide, and homicide. In terms of overall mortality and in contrast to the rest of the cohort, no "healthy worker effect" was seen (SMR = 1.00). They also showed increases in several types of cancer including cancers of the pancreas and prostate and leukemia. These unusual experiences cannot be explained either on the basis of their war-related deaths or on their period of employment (one-half were terminated within 1 year from date of hire), and data is insufficient to separate the role of hiring practices or their socioeconomic status. However, their life-styles were probably quite different judged from the fact that alcoholism-related deaths were increased as much as fivefold. Almost two-thirds of the total deaths occurred among 4,080 workers in the before 1940 subcohort. Further, the 5,117 workers of the after-1945 subcohort contributed only 5% of the total deaths. Thus, the results of the original refinery cohort (1937-1978) primarily reflect the experience of those employees hired before 1940. Given the same cohort method (historical prospective), cohort results vary widely according to different study designs, and this has implications for "generalizable" risk assessment or risk projections. A prospective study of new hires with 30 years of follow-up is rather inefficient because it would yield only a small number of deaths, with a strong healthy worker effect. The same is true for studies based on active workers with a short period of follow-up. Studies based on time of hire, however, provide a means for controlling time-related occupational exposures.  相似文献   
104.
Equations have been developed that relate the concentration (or a parameter directly proportional to concentration, such as optical absorbance) of a weakly ionizable solute in a water-immiscible phase, in equilibrium with an aqueous phase, to the pH of the aqueous phase, the partition coefficient of the unionized solute and the phase volume ratio. These relationships have been used in the design of experimental methods for determining partition coefficients, which require measurement of solute concentration in only one phase. Data obtained in this way permit ready recognition of deviations from assumptions made in the development of the model; these assumptions include insolubility of the ionized solute in the water-immiscible phase and lack of interaction between buffer components and solute. Conditions for optimal liquid—liquid extraction of weakly ionizable solutes are more easily recognized. With these techniques, the negative logarithm of the acid dissociation constant (pKa) and the logarithm of the octanol—water partition coefficient (log P) have been measured for warfarin (pKa = 5.15 ± 0.04; log P = 2.82 ± 0.06), strychnine (pKa = 8.29 ± 0.02; log P = 2.23 ± 0.04), phenol (pKa = 9.88 ± 0.02; log P = 1.75 ± 0.05), procaine (pKa = 8.11 ± 0.04; log P = 1.10 ± 0.08), and ephedrine (pKa = 9.92 ± 0.01; log P = 1.65 ± 0.04) at 21°C.  相似文献   
105.
【目的】 总结科技期刊封面设计流程管理模式并探讨其中的相关问题,为同行提供经验借鉴。【方法】 从版面、设计风格等方面对科技期刊封面图片的特征进行归纳。以中国激光杂志社期刊封面为例,总结封面设计流程管理模式,探讨封面设计过程中的相关问题。【结果】 期刊应对封面的主题策划、生产流程、版权保护等方面进行有效的流程管理。此外,就封面设置及风格、元素文化、版权意识、与设计公司合作等问题进行思考总结。【结论】 科技期刊可通过合理的封面设计流程,将科技与艺术融合,更准确地传播前沿科技成果,并弘扬中国传统文化。  相似文献   
106.
【目的】 探索中文科技期刊封面发展的可行途径。【方法】 分析我国科技期刊封面设计现状以及制约中文科技期刊封面发展的瓶颈,并以《协和医学杂志》为例,介绍其封面设计团队的建立和运营经验,展示封面设计在其期刊品牌建设中发挥的作用。【结果】 中文科技期刊在编委人才梯队化建设过程中,通过主动发现和利用青年人才,能够建立稳定的封面设计团队,呈现高水平的封面设计,进而显著提升期刊品牌影响力。【结论】 封面质量建设对提升期刊品牌影响力具有重要作用,紧密结合中文期刊自身发展特点,善于借助可利用的优势资源,是中文科技期刊突破封面发展瓶颈的可行途径。  相似文献   
107.
目的 分析中药治疗糖尿病肾脏疾病(DKD)随机对照试验中结局指标的使用情况和其他试验设计要素,为中药治疗DKD临床试验的设计及核心指标集的构建提供依据。方法 计算机检索知网、万方、维普、中国生物医学等7个医学数据库及2个临床试验注册中心(clinicaltrials.gov、chinadrugtrials.org.cn)近5年收录的中药治疗DKD随机对照试验,运用Cochrance手册对纳入的文献进行偏倚风险评估,对结局指标及其他试验设计要素进行统计与分析。结果 共纳入97项随机对照试验(RCTs),包含5项试验注册方案,研究发现,97项研究总体偏倚风险较高;DKD Ⅲ期(36项,41.38%)和气阴两虚兼血瘀证(16次,26.23%)为应用最多的DKD分期及中医证型;92项RCTs的疗程最多96周,最少2周,其中52项(56.52%)研究疗程为12周;92项RCTs及5项注册试验共采用152种结局指标,使用1 040次,共分为8大类,实验室检查(血液)、实验室检查(尿液)、临床疗效、中医证候积分、生活质量量表、生命体征、其他指标及其他事件,应用频率较高的依次是血肌酐(68次,70.10%)、临床有效率(55次,56.70%)、空腹血糖(51次,52.58%)、尿素氮(48次,49.48%)、总胆固醇(47次,48.45%)、24 h尿蛋白定量(43次,44.33%)等;56项RCTs及2项注册试验共采用安全性指标53种,频数227次,使用频率较高的依次是,不良反应(49次,84.48%)、肝功能(28次,48.28%)、血常规(24次,41.38%)、心电图(17次,29.31%)、尿常规(14次,24.14%);10项RCTs及5项注册试验报告了主要结局指标;54项RCTs报告了临床有效率指标。结论 目前中药治疗DKD的RCTs结局指标设计尚不规范,未来应积极构建突显出中医药特色的核心结局指标集,提升临床研究的质量,提高试验结果的应用价值。  相似文献   
108.
BackgroundDespite policies and programmes aimed at housing people who are homeless, there are still people who live and sleep rough. This project used the skills and knowledge of people in this situation to identify a strategy to mitigate some of the risks.ObjectiveTo describe the development and conduct of a co‐design project involving people who are homeless.Setting/Group MembersA Working Group of 11 was formed following a careful recruitment process from people who had volunteered after consultation by the project team. The co‐design approach was guided by a set of principles.MethodsEight members of the Working Group were interviewed by an external researcher (RM). The approach was primarily deductive, with the principles adopted by the project team used as a framework for data collection and analysis. The co‐design process was captured by the project leaders (BK, PC) supplemented with documentation review and team discussions.ResultsThe group met weekly for 12 weeks, with 8‐10 members present on average. They reviewed information from the survey, contributed ideas for solutions and ultimately decided to provide information via print, a website and an event. Important factors in on‐going involvement were carefully selecting group members and making participation rewarding for them.Discussion/ConclusionsVulnerable people such as those experiencing homelessness can be excluded from decision‐making processes affecting them, as they can be perceived as hard to reach and unable to make a meaningful contribution. This project demonstrated that a carefully managed project, with sufficient resources and commitment, it was possible to involve people who are homeless and maintain involvement over an extended time period.Public ContributionThe Working Group reviewed survey findings and developed an intervention to minimize the health, social and legal harms of sleeping rough. Several members reviewe this paper.  相似文献   
109.
目的系统论述孕产期保健管理信息系统开发设计实践,为建设类似信息系统提供参考。方法基于北京市妇幼保健网络信息系统孕产期保健管理子系统开发建设与升级改造进行案例研究。结果在需求分析基础上,明确系统建设内容和主要功能,采用适宜的技术架构和网络架构进行开发设计,实现对孕产期保健管理工作的信息化支撑保障。结论孕产期保健管理信息系统实现了社区、产检机构、分娩机构之间的数据实时共享,有助于优化管理流程,促进孕产期保健管理职能机构的业务协同。  相似文献   
110.
 目的 调查医院感染预防与控制课程设计中医学生的教育需求及教师的课程设计建议。方法 采用问卷调查全国5个地区10所医学院校师生的医院感染预防与控制教育需求和课程设计意见,参考塔巴目标模式课程设计步骤,论证课程设计方案。结果 584名学生中,仅11.8%(69名)的学生认为当前医院感染预防与控制教育能完全满足其需求,需求得分居前四位的为手卫生、消毒灭菌隔离、医院感染概论和职业防护。352名教师中,72.7%(256名)建议设必修课;86.4%(304名)选择总学时8~24学时,12.5%(44名)选择24学时以上,被调查教师建议10个章节学时平均总和为19.5;需重点掌握13项、熟悉9项知识和技能;86.4%(304名)教师建议理论与见习学时比为1 ∶0.5及以上;53.4%(188名)教师建议采取理论大课+小组见习(含技能操作)+线上学习的形式;63.7%(224名)教师建议师资团队由医院感染管理科+感染病科+护理部教师共同组成。结论 当前医学生的医院感染预防与控制教育远未完全满足需求,单独开课很有必要,建议设置16~24学时必修课,理论联系实践,多学科师资实施多元化教学,按照必修课考核。  相似文献   
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