髋臼螺钉对非骨水泥全髋置换术中假体稳定性的影响

目的探讨髋臼螺钉在非骨水泥全髋置换术中对髋臼假体稳定性的影响。 方法回顾性分析2009年8月至2015年8月在深圳市龙岗区人民医院骨科行非骨水泥全髋置换术114例(117髋)病例资料，患者根据术中是否植入髋臼螺钉分成两组，其中A组无螺钉组59髋，B组螺钉固定组58髋。分别在术后3个月、12个月、24个月和末次随访时对病人进行随访，评估并比较影像学的改变及Harris评分。A组57髋B组56髋获得完整随访资料，平均随访(5.7±1.6)年。以Kaplan-Meier法分析两组假体生存率。 结果A组平均手术时间(t＝2.213, P<0.05)、术中出血量均小于B组(t＝2.342, P<0.05)；随访末期，A、B组术后平均Harris评分为(95.0±2.1)分及(93.0±5.5)分(P>0.05)；A、B组术后3个月、12个月、24个月分别有4髋(7.0%)、3髋(5.3%)、1髋(1.8%)和1髋(1.8%)、2髋(3.6%)及2髋(3.6%)出现髋臼周围透亮线；A组1髋术后4年出现骨溶解，B组2髋出现骨溶解。以影像学证明假体松动作为失败标准，计算两组假体平均随访(5.7±1.6)年生存率分别为97%和95%，两者差异无统计学意义(P >0.05)。 结论髋臼骨质条件良好时是否使用髋臼螺钉固定对臼杯的稳定性无明显影响，全髋关节置换术中植入髋臼螺钉不是必需的。     

Factors influencing the diameter of human anterior and posterior intercostal arteries

At present, there have not been any detailed studies examining the size relationships of the intercostal arteries. This study was carried out to investigate the relationship between the vessel lumenal diameter of ipsilateral, paired anterior and posterior IC arteries, as well as with the length of the IC space supplied by each artery. Samples were collected from the second‐sixth anterior and posterior IC arteries near their site of origin, and the lengths of the corresponding IC spaces were measured in 42 cadavers. Lumenal diameters of both the anterior and posterior IC arteries at consecutive IC space closely followed second degree polynomial regression models (R² = 0.9655, and R² = 0.9741, respectively), and reached maximum size at the fifth IC space, which was found to be the longest of the IC spaces. No direct relationship was observed between diameters of the paired anterior and posterior IC arteries, although there was a trend for the larger anterior IC arteries to be paired with the larger posterior IC arteries. The calculated rate of blood flow at each IC artery was approximately two‐fold greater in males than in females. These results suggest that the length of the IC space, and hence the extent of the thoracic wall supplied, is a major factor in determining the diameter of both anterior and posterior IC arteries. Since COPD is such a prevalent disease, this study also examined its influence on the IC arteries, and found that the posterior IC arteries are significantly larger among afflicted subjects. Clin. Anat. 28:219–226, 2015. © 2014 Wiley Periodicals, Inc.     

变量变换回归分析(Ⅰ)——拟合含间断点资料的方法

本文目的是介绍一种能很好地拟合具有间断点资料的方法。当资料中具有明确的间断点或整个资料包含多段不同变化趋势的曲线类型时,为了提高曲线回归模型对资料的拟合优度,需要充分发挥"节点"的作用。可基于两种不同视角来利用"节点":其一,人为设定不同数目的节点,利用样条变换方法拟合分段多项式曲线;其二,在客观存在的节点上,求曲线的一阶乃至四阶导数,并据此构建曲线回归模型。得到的结论是:后者的拟合效果优于前者。     

Fractional Chebyshev pseudospectral method for fractional optimal control problems

In this paper, we introduce and apply a fractional pseudospectral method for indirectly solving a generic form of fractional optimal control problems. By employing the fractional Lagrange interpolating functions and discretizing the necessary optimality conditions at Chebyshev‐Gauss‐Lobatto points, the problem is converted into an algebraic system. By solving this system, the optimal solution of the main fractional optimal control problem is approximated. Finally, in some numerical examples, we show the applicability, efficiency, and accuracy of the proposed method comparing with some other methods.     

Parameter Identification in Uncertain Scalar Conservation Laws Discretized with the Discontinuous Stochastic Galerkin Scheme

We study an identification problem which estimates the parameters of the underlying random distribution for uncertain scalar conservation laws. The hyperbolic equations are discretized with the so-called discontinuous stochastic Galerkin method, i.e., using a spatial discontinuous Galerkin scheme and a Multielement stochastic Galerkin ansatz in the random space. We assume an uncertain flux or uncertain initial conditions and that a data set of an observed solution is given. The uncertainty is assumed to be uniformly distributed on an unknown interval and we focus on identifying the correct endpoints of this interval. The first-order optimality conditions from the discontinuous stochastic Galerkin discretization are computed on the time-continuous level. Then, we solve the resulting semi-discrete forward and backward schemes with the Runge-Kutta method. To illustrate the feasibility of the approach, we apply the method to a stochastic advection and a stochastic equation of Burgers' type. The results show that the method is able to identify the distribution parameters of the random variable in the uncertain differential equation even if discontinuities are present.     

Virtual implantations to transition from porcine to bovine animal models for a total artificial heart

Realheart total artificial heart (TAH) is a novel, pulsatile, four-chamber total artificial heart which had been successfully tested acutely in a porcine animal model. However, the bovine model is better suited for long-term testing and thus an evaluation of how the design would fit the bovine anatomy was required. Virtual implantation is a method that enables a computer simulated implantation based on anatomical 3D-models created from computer tomography images. This method is used clinically, but not yet adopted for animal studies. Herein, we evaluated its suitability in the redesign of the outer dimensions and vessel connections of Realheart TAH to transition from the porcine to the bovine animal model. Virtual implantations in combination with bovine cadaver studies enabled a series of successful acute bovine implantations. Virtual implantations are a useful tool to replace the use of animals in early device development and refine subsequent necessary in vivo experiments. The next steps are to carry out human virtual implantations and cadaver studies to ensure the design is optimized for all stages of testing as well as the final recipient.     

寻找HLA匹配无关供者概率曲线的计算及其应用

目的　建立在骨髓库中寻找到HLA匹配供者概率曲线P的回归方程式 ,并用于评估骨髓库的最适大小。方法　在哈迪 -温伯格群体中的HLA单体型频率可以从供者表型资料求得。寻找到一个HLA匹配供者的概率可以表示成供者数和HLA单体型频率的函数。使用对数曲线拟合方法推导出该概率曲线的回归方程。结果　笔者推导出在中国人骨髓库中寻找到至少一例HLA -A ,B ,DR抗原全配合供者概率的回归方程式为P =- 0 .6 7+0 .2 5lgN(N为骨髓库中的供者数 ,介于 5万到 1 0 0万 )。在骨髓库供者数达到 75万人时 ,大约 80 %的患者可以找到HLA配合供者。结论　找到HLA配合供者概率取决于骨髓库供者人数的多寡以及HLA单体型频率。HLA群体遗传学资料有助于决定骨髓库的最适大小及其供者成员的组成。     

A new automated method versus continuous positive airway pressure method for measuring pressure-volume curves in patients with acute lung injury

Objective  To compare pressure–volume (P–V) curves obtained with the Galileo ventilator with those obtained with the CPAP method in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Design  Prospective, observational study. Setting  General critical care center. Patients and participants  Patients with ALI/ARDS and receiving mechanical ventilation. Interventions  Pressure–volume curves were obtained in random order with the CPAP technique and with the software PV Tool-2 (Galileo ventilator). Measurements and results  In ten consecutive patients, airway pressure was measured by a pressure transducer and changes in lung volume were measured by respiratory inductive plethysmography. P–V curves were fitted to a sigmoidal equation with a mean R ² of 0.994 ± 0.003. Intraclass correlation coefficients were all >0.75 (P < 0.001 at all pressure levels). Lower (LIP) and upper inflection (UIP), and deflation maximum curvature (PMC) points calculated from the fitted variables showed a good correlation between methods with intraclass correlation coefficients of 0.98 (0.92, 0.99), 0.92 (0.69, 0.98), and 0.97 (0.86, 0.98), respectively (P < 0.001 in all cases). Bias and limits of agreement for LIP (0.51 ± 0.95 cmH₂O; −1.36 to 2.38 cmH₂O), UIP (0.53 ± 1.52 cmH₂O; −2.44 to 3.50 cmH₂O), and PMC (−0.62 ± 0.89 cmH₂O; −2.35 to 1.12 cmH₂O) obtained with the two methods in the same patient were clinically acceptable. No adverse effects were observed. Conclusion  The PV Tool-2 built into the Galileo ventilator is equivalent to the CPAP method for tracing static P–V curves of the respiratory system in critically ill patients receiving mechanical ventilation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

基于曲线拟合法与算术平均法计算双探头SPECT旋转中心漂移值的比较

目的 研究基于曲线拟合法与算术平均法计算单光子发射计算机断层成像（SPECT）设备探头旋转中心漂移值的差异性。方法 选取3个厂家的9台SPECT设备,每台设备都分别用曲线拟合法与算术平均法计算探头旋转中心漂移值,比较两种计算方法计算结果的差异性。同时将探头按照厂家分组,根据各厂家规定的合格值,将两种计算方法的结果与厂家自带软件计算的结果进行比较。结果 一共13个探头的13组数据中,两种计算方法计算结果之间数据差异无统计学意义（P>0.05）,两种计算方法计算结果分别与厂家计算结果之间比较,数据差异均无统计学意义（P>0.05）。两种计算方法计算结果分别与厂家计算结果相比,通过性均一致。结论 两种方法均能为旋转中心漂移的检测提供参考。