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91.
《Gait & posture》2014,39(1):107-112
Quiet standing posture in humans has often been modeled as a single inverted pendulum pivoting around the ankle joint. However, recent studies have suggested that anti-phase action between leg and trunk segments plays a significant role in stabilizing posture by reducing the acceleration of the center of mass (COM) of the body. The aim of this study is to test the hypothesis that anti-phase action is attenuated in the elderly compared to the young. The anterior–posterior movements of leg and trunk segments were measured using 4 laser displacement sensors from 22 healthy young subjects (age range, 20–35 years) and 38 healthy elderly subjects (age range, 57–80 years) standing quietly for 30 s twice. To focus on the segmental action between trunk and legs, we applied constraints (i.e., wooden splints) on each segment. We found that the velocity and acceleration of the COM (standard deviation of the time series was evaluated) were significantly higher for the elderly subjects than for young subjects. The increase in the acceleration of the COM resulted not only from an increase in the angular acceleration of the segments but also from the reduction of their anti-phase relationship, as demonstrated by an index that quantifies the degree of cancelation between both segments. We conclude that the degree of anti-phase action between trunk and leg segments during quiet standing is smaller for elderly subjects than for young subjects, and that this change of the anti-phase action due to aging resulted in increased COM acceleration in the elderly subjects. 相似文献
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93.
谭先杰 《中国实用妇科与产科杂志》2019,35(1):1-7
谭先杰教授:郎大夫您好,感谢您接受《中国实用妇科与产科杂志》委托我对您进行的采访。说来惭愧,尽管从朋友圈中多次看到您在全国讲《妇产科临床诊治中的陷阱和对策》,但我居然没有能完整地听过这一堂课。这样也好,我可以从普通读者的角度来向您请教。请问您为什么要用“陷阱”作为关键词来阐述您的观点呢? 相似文献
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The objective of this retrospective study is to more fully understand the optimal strategy to manage spinal arteriovenous (AV) shunts. This study included a cohort of 35 patients with a diagnosis of spinal AV shunts who were treated over the past 10 years at a single institute. Angiographic diagnosis of intramedullary AV malformations (IM-AVM), perimedullary AV fistulas (PM-AVF), dural AV fistulas (D-AVF), or epidural AV fistulas (ED-AVF) was carefully made, and the microsurgical or endovascular strategy for them was determined at the interdisciplinary meeting consisting of neurospinal surgeons and endovascular specialists. Endovascular surgery was first considered whenever safely possible. Microscopic direct surgery using intraoperative image guidance was considered for cases in which endovascular access was challenging or not safely possible. Combined treatment was another option. The clinical condition was assessed using the modified Rankin scale (mRS). Seventeen of 35 cases were treated with microscopic direct surgery, 13 cases with endovascular surgery, and the remaining five cases with the combination. Complete angiographic obliteration was achieved in 30 of 35 cases (85.7%). Although residual AV shunts was recognized in 3 cases of IM-AVM, 1 case of PM-AVF and 1 case of ED-AVF, no angiographic recurrence was present with an average postoperative follow-up period of 44 months. The average mRS before surgery was 2.37 and significantly improved to 1.94 at the most recent follow-up. Interdisciplinary collaboration between neurospinal surgeons and endovascular specialists should be standard to achieve safe and successful outcomes in treating such rare and difficult spinal disorders. 相似文献
96.
在直流分布式电源系统的设计过程中,稳定性设计是最核心但最复杂的部分。随着系统规模日益庞大,若想将其作为整体进行稳定性设计几乎是不可能的。由于级联是分布式结构中最基本的连接形式,故深入研究、改善级联系统的稳定性对于确保整个系统的稳定运行非常重要。除优化设计变流器参数外,增加母线补偿装置(VBC)也是改善级联系统直流母线电压稳定性的一种有效途径,目前针对DC-DC级联系统母线补偿策略及补偿容量的研究已取得了一定的成果,其中一些研究还可以应用于大信号扰动的场合。但总体而言仍有进一步探索和发展的空间。本文从大信号的研究角度出发,基于混合势函数理论和回转器大信号模型,提出了一种直流母线电压补偿控制策略。该控制策略可根据级联系统中源、负载变流器的具体特性参数进行有针对性的补偿;同时,该策略由混合势函数理论的稳定性定理推导得出,从理论上保证了加入VBC后整个系统在大信号扰动下的稳定性。仿真和实验以峰值电流模式控制型Buck变流器级联系统为例对该补偿控制策略的有效性和补偿效果进行了验证。 相似文献
97.
Hepatitis B, a serious infectious disease caused by the hepatitis B virus (HBV), remains a worldwide social and public health problem. Hepatitis B has a particularly high incidence rate in the world, whereas approximately 35–50% HBV carriers are infected through vertical transmission. Even after newborn immunoprophylaxis, vertical transmission still accounts for 5–10% in China according to plenty of literature in Chinese language. For these reasons, it is important to determine how to effectively intervene in mother-to-child transmission (MTCT). To date, though, intervention methods and measures remain controversial. In order to understand the mechanism of MTCT intervention further and develop effective preventions and interventions, a comprehensive analysis and presentation on some of its more controversial issues will be given in this paper. And eventually we conclude three measures and strategies for these issues: (1) emancipate the mind and seek truth from facts to understand the controversial issues pertaining to MTCT of HBV; (2) treat the basic rules and changing characteristics of MTCT blocking process of hepatitis B with holistic medical thought dialectically and (3) further explore the interaction of genetic susceptibility and environmental factors of MTCT of hepatitis B. 相似文献
98.
林凤 《中国实用妇科与产科杂志》2022,38(9):881-885
宫腔粘连是子宫内膜基底层损伤所引起的疾病,严重影响女性生理健康和生育功能。宫腔镜下宫腔粘连分离术作为子宫腔整复手术的首选治疗方法,以恢复子宫正常解剖结构及功能为目的,但术后复发仍是妇科医生面临的巨大挑战。目前防治术后再粘连的方法主要有屏障治疗、激素治疗和羊膜疗法等,其他的治疗选择,如干细胞疗法、阿司匹林、富血小板血浆、西地那非等治疗尚处于研究当中。目前尚无防治术后再粘连的最佳治疗方案,如何达到最佳治疗效果仍需进一步研究。 相似文献
99.
《Clinical microbiology and infection》2022,28(8):1151.e9-1151.e16
ObjectivesTo evaluate whether simplification of antiretroviral treatment to dual therapy (DT) negatively impacts immune recovery (IR), immune activation and inflammation (IA/I), and HIV reservoir.MethodsAn open-label, single-centre, randomized controlled trial conducted in adult virologically suppressed HIV-infected patients on triple therapy (TT) with elvitegravir-cobicistat, emtricitabine and tenofovir alafenamide or dolutegravir (DTG), abacavir, and lamivudine (3TC). Participants were randomized to continue TT or switch to DTG, or darunavir/cobicistat (DRVc) plus 3TC. IR was assessed by CD4+/CD8+ ratio at 48 and 96 weeks. Changes in immune activation, proliferation, exhaustion, senescence, and apoptosis in CD4+ and CD8+ T cells, plasma sCD14, hsCRP, D-dimers, β2-microglobulin, IL-6, TNF-α and IP-10 levels, cell-associated HIV-DNA (CA-DNA), and unspliced HIV-RNA (usRNA) were also analysed.ResultsOne hundred and fifty-one participants were enrolled. Fourteen patients did not complete the follow up. In the ITT and PP analysis, the IR was similar between the treatment arms. In the ITT analysis, the median increase in CD4+/CD8+ ratio was 0.10, 0.04, and 0.07 at week 48, and 0.09, 0.05, and 0.08 at week 96 for TT, DTG/3TC, and DRVc/3TC, respectively. After adjusting for confounding factors, the slopes of changes in CD4+/CD8+ ratio over time were independent of treatment (F = 1.699; p = 0.436) and related only to baseline values (F = 756.871; p = 0.000). There were no differences in IA/I, CA-DNA, or usRNA between treatment arms.DiscussionBoth IR and IA/I, CA-DNA, and usRNA were similar in the three treatment groups, regardless of maintaining TT or simplifying to DTG/3TC or DRVc/3TC in virologically suppressed HIV-infected patients. 相似文献
100.
目的:构建肿瘤细胞减灭程度(completeness of cytoreduction,CC)预测模型,为肿瘤细胞减灭术(cytoreductive surgery,CRS)加腹腔热灌注化疗(hyperthermic intraperitoneal chemotherapy,HIPEC)治疗胃癌腹膜转移(gastric cancer with peritoneal metastasis,GCPM)提供病例筛选方法。方法:比较完全CRS(complete CRS,CCRS)组和不完全CRS(incomplete CRS,ICRS)组患者基本临床病理特征和治疗参数,通过逻辑回归模型筛选CC独立预测因子,精准预测CCRS可能性。结果:125例患者纳入本研究,其中CC0组52例(41.6%),中位总生存期为30.0(95%CI:16.8~43.3)个月;CC1-3组73例,中位总生存期7.3(95%CI:5.7~8.8)个月,差异有统计学意义(P<0.001),而CC1、CC2和CC3组间中位总生存期差异无统计学意义(P>0.05)。因此,CC0定义为CCRS组,CC1-3定义为ICRS组,构建并优化了以腹膜转移时相(OR=14,95%CI:2.0~97.9,P=0.008)、术前肿瘤标志物(OR=6.5,95%CI:2.1~37.8,P=0.037)和腹膜癌指数(OR=1.5,95%CI:1.3~1.8,P<0.001)预测ICRS的多因素回归模型和预测列线图,内部验证显示,ROC曲线下面积为0.985,列线图显示预测准确度、一致性良好。根据列线图结果将患者分为4个亚组,设定CCRS预测概率≥50%,同时性且术前肿瘤标志物正常组、同时性且术前肿瘤标志物异常组、异时性且术前肿瘤标志物正常组、异时性且术前肿瘤标志物异常组腹膜癌指数界值点分别为:≤16、≤12、≤10和≤5。结论:CCRS+HIPEC可延长部分经选择的GCPM患者生存期,以腹膜癌指数为核心,联合腹膜转移时相和术前肿瘤标志物的病例筛选策略,可有效选择高概率实现CCRS的患者接受CCRS+HIPEC治疗。 相似文献