Three-dimensional joint kinematics of ACL-deficient and ACL-reconstructed knees during stair ascent and descent

Mechanical environmental changes in the knee are induced by altered joint kinematics under cyclic loading during activities of daily living after anterior cruciate ligament (ACL) injury. This is considered a risk factor in progressive cartilage degeneration and the early onset of osteoarthritis following ACL injury and even after reconstructive surgery. The purpose of this study was to examine 3D joint kinematics of ACL-deficient and ACL-reconstructed knees to health controls during stair ascent and descent. A 3D optical video motion capture system was used to record coordinate data from reflective markers positioned on subjects as they ascended and descended a custom-built staircase. Spatiotemporal gait and knee joint kinematic variables were calculated and further analyzed. The ACL-deficient knees exhibited a significant extension deficit compared to the ACL-intact controls. A more varus and internally rotated tibial position was also identified in the ACL-deficient knees during both stair ascent and descent. The ACL-reconstructed knees exhibited less abnormality in both spatiotemporal gait parameters and joint kinematics, but these variables were not fully restored to a normal level. The kinematic profiles of the ACL-reconstructed knees were more similar to those of the ACL-deficient knees when compared to the ACL-intact knees. This suggests that the ACL-reconstructed knees had been "under-corrected" rather than "over-corrected" by the reconstructive surgery procedure. Findings from this study may provide more insight with respect to improving ACL reconstruction surgical techniques, which may aid the early progression of cartilage degeneration in ACL-reconstructed knees.     

Nourishing or suppressing? The contradictory influences of perception of organizational politics on organizational citizenship behaviour

Drawing on both social exchange theory and impression management theory, this study sought to explain how perception of organizational politics (POP) influences organizational citizenship behaviour (OCB) through two contrary psychological processes. We proposed that through the mediation of job satisfaction, POP has an inhibiting effect on OCB; through the mediation of careerism, POP has a nourishing effect on OCB. Data were obtained from 393 police officers and their colleagues from a city police department in northern Taiwan. Results from structural equation modelling (SEM) revealed that the relationship between POP and OCB was negatively mediated by job satisfaction and positively mediated by careerism. Such antithetical psychological processes imply that employees may experience psychological dilemmas over the performance of OCB when they perceive their organization as political. Implications for theory and future research are discussed.     

Does Positivity Matter? The Impact of Interparental Interactions on Young Adult Conflict Management

The main purpose of our study was to examine the impact of positive inter-parental interactions on the conflict management of young adults. Based on social cognitive theory (SCT), it was hypothesized that exposure to interparental positive interactions would mediate the intergenerational transmission of conflict. The findings only partially supported SCT and provided evidence for intergenerational transmission of conflict. However positivity did not buffer this association. Important contributions of this study include a better theoretical understanding of positivity in relationships and evidence for the intergenerational transmission of positive and negative conflict management tactics. Implications for researchers, clinicians, and educators are presented.     

论风险观念的价值哲学基础

<正>"风险社会"理论的兴起和风险观念的确立,不仅意味着以"核风险、化学产品风险、基因工程风险、生态灾难风险"为代表的越来越多的全球性问题成为当今人类社会发展所必须面对的重大社     

对角线元素与不同复杂度的系统的关系

<正>对角线方法是指德国学者康托尔 ( G. Cantor) 在证明实数集不可数时所运用的一种技术方法。在这种意义上,康托尔的实数集不可数论本身便是对角线方法的一种重要运用。此外,对角线方法还有两种重要运用,即哥德尔对角线定理和汤姆逊引理的证明。哥德尔对角线定理又叫 "哥德尔自指定     

高通量血液透析对老年患者并发症的临床观察

研究高通量血液透析对老年透析患者常见并发症治疗的疗效.通过前瞻性试验研究,试验组为18例老年透析患者采用高通量血液透析,对照组为28例老年透析患者采用常规维持性血液透析.试验1年后分别测定顽固性高血压、症状性低血压、肌痉挛、心律失常、心绞痛及皮肤搔痒的发生率.结果试验组透析患者并发症明显缓解,对照组发生率明显上升(P＜0.05).因此,高通量血液透析可以明显降低透析相关并发症的发生,改善患者生活质量和生存质量.     

2例异位甲状腺误诊的讨论

探讨异位甲状腺的临床特征、诊断及处理.报导2例误诊的异位甲状腺患者的临床资料,其中一例临床诊断为甲状舌管囊肿,另一例临床诊断为血管瘤.结果2例均行手术切除,一例术后证实为副甲状腺,另一例则为迷走甲状腺需终身服用甲状腺素.医生对异位甲状腺的认识不足及诊断思路较窄,是导致误诊、误治的主要原因.     

大型公立医院开展特需医疗服务的思考

随着生活水平的提高,人们的健康需求不断提高,有支付能力的人群不断增多.同时,特需医疗存在巨大的利润空间,使许多大型公立医院争相提供特需医疗服务.但是,大型公立医院作为特需医疗服务的提供主体存在许多的问题,要逐渐使大型公立医院分流,使营利性医院逐步成为特需医疗的主要提供主体.     

自我控制的能量模型:证据、质疑和展望

自我控制的能量模型是解释自我控制的一个重要理论模型。该模型认为,所有的自我控制行为依赖一种共同且有限的能量,执行自我控制会消耗这种能量,导致自我损耗效应的产生,但能量也可以通过一些方法得以恢复和提升。该模型得到大量行为和生理层面研究的支持,但也有研究者从疲劳、情绪、动机、血糖指标、时间知觉等方面提出质疑。未来研究可从自我能量的性质、总量等角度进一步完善能量模型,同时结合我国文化探讨理想、信念、价值观对提升我国国民意志力的作用。     

Different types of exercise induce differential effects on neuronal adaptations and memory performance

Different exercise paradigms show differential effects on various forms of memory. We hypothesize that the differential effects of exercises on memory performance are caused by different neuroplasticity changes in relevant brain regions in response to different exercise trainings. We examined the effects of treadmill running (TR) and wheel running (WR) on the Pavlovian fear conditioning task that assesses learning and memory performance associated with the amygdala (cued conditioning) and both the amygdala and hippocampus (contextual conditioning). The skeletal muscle citrate synthase activity, an indicator of aerobic capacity, was elevated in rats received 4 w of TR, but not WR. While both TR and WR elevated the contextual conditional response, only TR facilitated the cued conditional response. Using a single-neuron labeling technique, we found that while both TR and MR enlarged the dendritic field and increased the spine density in hippocampal CA3 neurons, only TR showed these effects in basolateral amygdalar neurons. Moreover, both types of exercise upregulated synaptic proteins (i.e., TrkB and SNAP-25) in the hippocampus; however only TR showed similar effects in the amygdala. Injection of K252a, a TrkB kinase inhibitor, in the dorsal hippocampus or basolateral amygdala abolished the exercise-facilitated contextual or cued fear learning and memory performance, respectively, regardless of the types of exercise. In summary, our results supported that different types of exercise affect the performance of learning and memory via BDNF-TrkB signaling and neuroplasticity in specific brain regions. The brain region-specific neuronal adaptations are possibly induced by various levels of intensity/stress elicited by different types of exercise.