三种髓内固定技术治疗老年股骨粗隆间骨折对患者股骨头旋转与固定钉滑脱的影响

目的：比较Gamma钉、PFNA和InterTan三种髓内固定技术治疗老年股骨粗隆间骨折对患者股骨头旋转与固定钉滑脱的影响。方法回顾性分析我科2011年6月至2015年6月期间采用上述三种髓内固定技术治疗的122例老年股骨粗隆间骨折患者的临床资料,其中31例采用3代Gamma钉固定技术,50例采用PFNA固定技术,41例采用InterTan固定技术。统计分析三组患者在放射学上的Evans-Jensen分型、术后4周固定钉滑脱量与股骨头旋转率。结果 Gamma钉、PFNA、InterTan三组患者术后4周的固定钉滑脱量分别为(4.40±1.21) mm、(4.35±1.43) mm、(4.18±1.36) mm,差异无统计学意义(P>0.05),而术后4周股骨头旋转率分别为22.6%(7/31)、8.0%(4/50)、2.4%(1/41),差异具有统计学意义(P<0.05)。结论对于老年股骨粗隆间骨折髓内钉固定术后患者,其股骨头旋转与固定钉滑脱量无关,而与近端固定钉的防旋特性(或设计特性)有关。InterTan可能更适合用于高Evans-Jensen分型的骨折患者。     

Robust singular optimization for linear time varying systems by integral high‐order sliding mode

This paper presents an approach to solve a singular quadratic optimization problem for linear time varying systems based on the so‐called integral high‐order sliding mode control. The plant which is time varying is affected for some bounded disturbances, and the criterion to minimize is degenerated, in the sense that the weighting matrix can possess any rank. It is shown the natural connection between the order of singularity of the time varying quadratic criterion, which is connected to the rank of the cost matrix and the order of the sliding mode. An integral high‐order sliding mode is proposed to control the behavior of the transit phase before arriving toward the corresponding higher order singular time varying optimal manifold in prescribed time. The transformation to the phase‐variable form for the Linear Time Variant Systems (LTVS) becomes the key step to solve the problem, and the proposed solution provides the insensitivity of trajectory w.r.t. matched bounded uncertainties. Such a design is applied to a probe landing problem to illustrate the effectiveness of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd.     

双联滑移齿轮轴向排列最小宽度的剖析

本文阐述了双联滑移齿轮在适当传动出情况下,轴向移动一个齿轮宽度就可以进行变速的可行性及适用场合。而一般书籍介绍,双联滑移齿轮的变速轴向至少移动二个齿宽。     

Hybridized gravitational search algorithm tuned sliding mode controller design for load frequency control system with doubly fed induction generator wind turbine

In this paper, the load frequency regulation problem of 2‐area interconnected power system is resolved using the sliding mode control (SMC) methodology. Interconnected 2‐area power systems with and without doubly fed induction generator wind turbines are considered for implementing the proposed optimal control methodology. Here, a heuristic gravitational search algorithm (GSA) and its variants such as opposition learning–based GSA (OGSA), disruption‐based GSA (DGSA), and disruption based oppositional GSA (DOGSA) are employed to optimize the switching vector and feedback gains of SMC. In order to overcome the inherent chattering problem in SMC, the control signals are considered in the objective function. The robustness of optimized SMC is analyzed by the inclusion of nonlinearities such as generation rate constraint (GRC), governor deadband, and time delay during the signal processing between the control areas, which are present in the real‐time power system. The insensitiveness of the optimal controller is shown by variation in system parameters like loading condition, speed governor constant, turbine constant, and tie‐line power coefficient. Further, the optimal SMC has been studied with significant load variations and wind power penetration levels in the control areas. The potential of proposed SMC design with chattering reduction feature is shown and validated by comparing the results obtained with the other reported methods in the literature.     

Experimental study of posttraumatic regeneration of the epithelium of the gastric and intestinal mucosa in dogs

Sources of repetitive regeneration of the epithelium of the gastric and intestinal mucosa were studied. To do this, several operations were performed on the stomach and intestine of 16 dogs. The investigations showed that a leading role in the regeneration of the epithelium of the gastric and intestinal mucosa under experimental conditions is played by the intact epithlium surrounding the zone of the operation. This is confirmed by the fact that an intestinal graft on a vascular pedicle, stripped of its mucosa and sutured into a defect in the stomach wall, is covered by gastric mucosa, whereas a stomach graft, stripped of its mucosa, is covered by intestinal mucosa if it is transplanted as a cylindrical insert into the intestinal tube; a small gastric pouch, if stripped of its mucosa, is obliterated, as is completely explained by the absence of the main source of regeneration, namely intact epithelium of the mucosa at the periphery of the defect. Regeneration of the epithelium of the gastric mucosa from implanted cells could not be demonstrated; consequently, regeneration under the experimental conditions used took place as a result of sliding of epithelial cells surrounding the zone of the operation over the denuded surface.Presented by Academician of the Academy of Medical Sciences of the USSR V. S. Savel'ev.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 883–885, July, 1976.     

心音的非线性时间序列分析

本文通过非线性时间序列分析的方法来分析心音时间序列,获得有关冠状动脉阻塞的血液动力学特征信息.对结果进行统计分析后,冠状动脉阻塞患者的心音与正常人相比在动力学特征上是具有显著性差异的.而且对于正常人来说血液动力学特征有标度的性质,而冠状动脉阻塞的,没有明显的标度性质.这有助于冠状动脉阻塞的无创检测.     

Nucleosome positioning in a model of active chromatin remodeling enzymes

Accounting for enzyme-mediated active sliding, disassembly, and sequence-dependent positioning of nucleosomes, we simulate nucleosome occupancy over cell-cycle-scale times using a stochastic kinetic model. We show that ATP-dependent active nucleosome sliding and nucleosome removal processes are essential to obtain in vivo-like nucleosome positioning. While active sliding leads to dense nucleosome filling, sliding events alone cannot ensure sequence-dependent nucleosome positioning: Active nucleosome removal is the crucial remodeling event that drives positioning. We also show that remodeling activity changes nucleosome dynamics from glassy to liquid-like, and that remodeling dramatically influences exposure dynamics of promoter regions.     

自滑式矫治器在Angle Ⅱ类错中的应用

目的:研究自滑式矫治器在AngleⅡ类错中治疗前牙深覆中的临床疗效。方法:通过自滑式矫治器配合固定治疗技术治疗AngleⅡ类错。结果:自滑式矫治器可随同各种固定矫治技术在治疗中控制前牙区的垂直向移动,在矫治过程中改变曲线的深度时即以改善口唇的突度。结论:在Ⅱ类错中应用自滑式矫治器可在短期内很好的打开咬合,改善患者面部的侧貌。