Role of computational fluid mechanics in the analysis of prosthetic heart valve flow

The paper aims to present the strengths and weaknesses of computational fluid mechanics (CFM) compared with existing in vitro haemodynamic techniques such as LDA, hot-wire anemometry and static pressure measurement, and to discuss the application of CFM to the analysis of prosthetic heart valve flow. It presents a brief summary of existing methods used in analysing in vitro heart valve flow (along with CFM), the special problems inherent in each method and the quantities each is capable of giving. The analysis then goes on to present examples of information yielded by CFM. It also contains a brief discussion of the data requirements for the analysis of heart valve performance and the clinical relevance of fluid dynamic occurrences. The conclusion drawn is that CFM has a major role to play in the analysis of prosthetic heart valve flow and design because of the improved availability of data afforded and the increased correlation between CFM and clinical flow regimes, due to the ability to consider realistic models of blood.     

What and where in human audition: selective deficits following focal hemispheric lesions

A sound that we hear in a natural setting allows us to identify the sound source and localize it in space. The two aspects can be disrupted independently as shown in a study of 15 patients with focal right-hemispheric lesions. Four patients were normal in sound recognition but severely impaired in sound localization, whereas three other patients had difficulties in recognizing sounds but localized them well. The lesions involved the inferior parietal and frontal cortices, and the superior temporal gyrus in patients with selective sound localization deficit; and the temporal pole and anterior part of the fusiform, inferior and middle temporal gyri in patients with selective recognition deficit. These results suggest separate cortical processing pathways for auditory recognition and localization. Electronic Publication     

Designs for Instruction, Designs for Change: Distributing Knowledge of Evidence-Based Practice

We comment on the target article by Weingardt (this issue), which discusses recent advances in instructional design and technology (IDT) and their implications for dissemination of evidence-based practices. These arguments are extended to the topic of psychological intervention design, and possibilities for new intervention structures are briefly explored. Finally, comments are offered on maintaining a careful balance between technological and social processes in the effort to promote the dissemination of innovative and evidence-based psychological procedures.     

Publication Guidelines for Heart Rate Studies in Man

Publication guidelines are provided for the collection, quantification, and analysis of heart rate data.     

A LISREL 8 model with constrained parameters for twin and adoptive families

Constrained optimization recently has been implemented in the LISREL software package, allowing formulation of parent-offspring transmission models in a simple and efficient manner. A reverse path model of parental transmission is described within the LISREL framework for application to twin and/or adoptive family data. The model incorporates genetic and environmental parameter constraints arising from assortative mating and cultural transmission. An illustration of the LISREL model is given using measures obtained from twins and parents involving fear of social criticism.     

利用CT扫描及CAD技术建立腰椎活动节段的有限元模型

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     

Perceptual Speed and IQ Are Associated Through Common Genetic Factors

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.     

Chemical and statistical considerations in the determination of partition coefficients of weakly ionizable drugs and poisons

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 (pK′_a) and the logarithm of the octanol—water partition coefficient (log P) have been measured for warfarin (pK′_a = 5.15 ± 0.04; log P = 2.82 ± 0.06), strychnine (pK′_a = 8.29 ± 0.02; log P = 2.23 ± 0.04), phenol (pK′_a = 9.88 ± 0.02; log P = 1.75 ± 0.05), procaine (pK′_a = 8.11 ± 0.04; log P = 1.10 ± 0.08), and ephedrine (pK′_a = 9.92 ± 0.01; log P = 1.65 ± 0.04) at 21°C.     

中国激光杂志社期刊封面设计的实践与思考

【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。     

中文科技期刊封面设计与探索——以《协和医学杂志》为例

【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。