装配式医院建筑设计探析——以横琴医院为例

以横琴医院项目为例,围绕综合医院和配套宿舍两大功能,分别介绍了装配式设计理念的应用,并进行了总结与思考,为我国医院项目的装配式设计提供参考。     

Coordinative and limb-specific control of bimanual movements in patients with Parkinson's disease and cerebellar degeneration

The present study examined the effects of basal ganglia and cerebellar pathology on bimanual coordination using patients with Parkinson's disease (PD) and cerebellar dysfunction (CD). Twenty patients with idiopathic PD (10 untreated early and 10 advanced PD), 10 patients with cerebellar degeneration, and 11 normal subjects were instructed to perform in-phase and anti-phase bimanual coordination movements. The results indicated that while the quality of coordinated bimanual movements in untreated early PD and CD patients was not significantly different from that of normal controls, advanced PD patients exhibited reduced synchronized coordination during the faster anti-phase mode. This suggests that the observed bimanual coordination abnormalities in PD are not an early sign of the pathophysiology of the disease, and cerebellar degeneration may have minimal consequences on synchronized coordination between the limbs. In terms of the parameterization of individual limb movements, CD patients showed a tendency for hypermetric impairments with more irregular movements, while PD patients exhibited relatively slower limb movements and lower amplitudes than normal controls. Overall, the current data provide evidence of the specific functions of different neural structures involved in the pathological process of PD and CD on bimanual coordination.     

Distinguishing vaccine efficacy and effectiveness

Background

Mathematical models of disease transmission and vaccination typically assume that protective vaccine efficacy (i.e. the relative reduction in the transmission rate among vaccinated individuals) is equivalent to direct effectiveness of vaccine. This assumption has not been evaluated.

Methods

We used dynamic epidemiological models of influenza and measles vaccines to evaluate the common measures of vaccine effectiveness in terms of both the protection of individuals and disease control within populations. We determined how vaccine-mediated reductions in attack rates translate into vaccine efficacy as well as into the common population measures of ‘direct’, ‘indirect’, ‘total’, and ‘overall’ effects of vaccination with examples of compartmental models of influenza and measles vaccination.

Results

We found that the typical parameterization of vaccine efficacy using direct effectiveness of vaccine can lead to the underestimation of the impact of vaccine. Such underestimation occurs when the vaccine is assumed to offer partial protection to every vaccinated person, and becomes worse when the level of vaccine coverage is low. Nevertheless, estimates of ‘total’, ‘indirect’ and ‘overall’ effectiveness increase with vaccination coverage in the population. Furthermore, we show how the measures of vaccine efficacy and vaccine effectiveness can be correctly calculated.

Conclusions

Typical parameterization of vaccine efficacy in mathematical models may underestimate the actual protective effect of the vaccine, resulting in discordance between the actual effects of vaccination at the population level and predictions made by models. This work shows how models can be correctly parameterized from clinical trial data.     

肱骨内植物材料选择及预紧力影响的参数化研究

背景：目前,关于肱骨及接骨板的生物力学研究较多,但甚少将两者组合为一个骨折固定模型并将材料及预紧力作为参数进行研究。〈br〉 目的：通过带接骨板的肱骨骨折有限元模型的生物力学仿真,比较不同接骨板和螺钉材料、预紧力对举重过程中接骨板及螺钉失效可能性的影响,以及对骨折应力遮挡效率的影响。〈br〉 方法：利用肱骨点云数据和接骨板及螺钉几何数据进行装配,得到带接骨板的肱骨骨折有限元模型,将举重动作逆向动力学仿真得到的关节力和肌肉力作为有限元仿真的载荷边界条件。采用相同的有限元模型进行参数化研究,比较不同接骨板和螺钉材料及预紧力对接骨板、螺钉、骨折缝及其周围肱骨应力变化的影响。〈br〉 结果：相同预紧力下,采用不锈钢材料接骨板和螺钉的应力大于钛合金和钛材料,即采用不锈钢材料接骨板和螺钉失效的危险性大于钛合金和钛材料;采用不锈钢材料时肱骨的应力遮挡率大于钛合金和钛材料;采用相同材料时,增加预紧力会导致接骨板和螺钉的应力增加,但会减小肱骨的应力遮挡率。〈br〉 结论：接骨板和螺钉的材料属性及预紧力大小等因素均对接骨板、螺钉以及骨的应力分布有一定影响。本文建立的分析方法同样适用于其它部位骨折固定的应力分析。     

Improving oxygenator performance using computational simulation and flow field-based parameters

Current goals in the development of oxygenators are to reduce extrinsic surface contact area, thrombus formation, hemolysis, and priming volume. To achieve these goals and provide a favorable concentration gradient for the gas exchange throughout the fiber bundle, this study attempts to find an optimized inlet and outlet port geometry to guide the flow of a hexagonal-shaped oxygenator currently under development. Parameters derived from numerical flow simulations allowed an automated quantitative evaluation of geometry changes of flow distribution plates. This led to a practical assessment of the quality of the flow. The results were validated qualitatively by comparison to flow visualization results. Two parameters were investigated, the first based on the velocity distribution and the second calculated from the residence time of massless particles representing erythrocytes. Both approaches showed significant potential to improve the flow pattern in the fiber bundle, based on one of the parameters of up to 66%. Computational fluid dynamics combined with a parameterization proved to be a powerful tool to quickly improve oxygenator designs.