Dynamic stability in runners with and without plantar fasciitis

BackgroundPlantar fasciitis (PF) is a common overuse injury experienced by runners. PF may decrease the ability of the plantar fascia to create tension and reduce stability of the foot. Stability of the foot is necessary for whole-body dynamic stability during running which consists of cyclical periods of single leg stance. Given that a major risk factor for running-related injury is previous injury, evaluating dynamic stability in runners with PF, runners with resolved PF, and healthy runners may elucidate differences between these individuals and clarify risk for secondary injury in these groups.Research questionIs dynamic stability reduced in runners with PF and runners with resolved PF compared to healthy runners?MethodsThirty runners were recruited for this retrospective comparative study based on mileage and injury status: current PF (PF), resolved PF (RPF), or healthy (CON). Kinematic and kinetic data were collected during running and dynamic stability was determined by time-to-contact (TtC) analysis for early, mid, and late stance to the anterior, posterior, medial, and lateral boundary of the foot. Dynamic stability was compared between groups one-way ANOVAs (α = 0.05) and Tukey post-hoc tests conducted when appropriate. Cohen’s d effect sizes (d) were reported for all TtC comparisons (small = 0.20, medium = 0.50, large = 0.80).ResultsTtC values were shorter in PF compared to the other groups to all boundaries during mid-stance. TtC was significantly greater in PF compared to RPF to the anterior boundary during late stance.SignificanceShorter TtC observed in PF compared to the other groups during midstance may indicate reduced dynamic stability during the most stable portion of running which may lead to increased injury risk.     

Stabilization and formulation of a recombinant Human Cytomegalovirus vector for use as a candidate HIV-1 vaccine

Live attenuated viral vaccine/vector candidates are inherently unstable and infectivity titer losses can readily occur without defining appropriate formulations, storage conditions and clinical handling practices. During initial process development of a candidate vaccine against HIV-1 using a recombinant Human Cytomegalovirus vector (rHCMV-1), large vector titer losses were observed after storage at 4 °C and after undergoing freeze-thaw. Thus, the goal of this work was to develop candidate frozen liquid formulations of rHCMV-1 with improved freeze-thaw and short-term liquid stability for potential use in early clinical trials. To this end, a virus stability screening protocol was developed including use of a rapid, in vitro cell-based immunofluorescence focus assay to quantitate viral titers. A library of ∼50 pharmaceutical excipients (from various known classes of additives) were evaluated for their effect on vector stability after freeze-thaw cycling or incubation at 4 °C for several days. Certain additives including sugars and polymers (e.g., trehalose, sucrose, sorbitol, hydrolyzed gelatin, dextran 40) as well as removal of NaCl (lower ionic strength) protected rHCMV-1 against freeze-thaw mediated losses in viral titers. Optimized solution conditions (e.g., solution pH, buffers and sugar type) slowed the rate of rHCMV-1 titer losses in the liquid state at 4 °C. After evaluating various excipient combinations, three new candidate formulations were designed and rHCMV-1 stability was benchmarked against both the currently-used and a previously reported formulation. The new candidate formulations were significantly more stable in terms of reducing rHCMV-1 titer losses after 5 freeze-thaw cycles or incubation at 4 °C for 30 days. This case study highlights the utility of semi-empirical design of frozen liquid formulations of a live viral vaccine candidate, where protection against infectivity titer losses due to freeze-thaw and short-term liquid storage are sufficient to enable more rapid initiation of early clinical trials.     

白及多糖超声提取工艺及其抗氧化活性研究

目的：优化白及多糖的超声提取工艺，比较不同产地白及多糖含量差异，考察白及多糖稳定性和抗氧化活性。方法：以多糖得率为考察指标，料液比、超声温度、超声时间为考察因素设计L9（34）正交试验优化白及多糖超声波提取工艺；以苯酚-硫酸法测定白及多糖含量，考察陕西汉中、云南普洱、湖南洪江及四川绵阳白及多糖含量产地差异；以化学方法考察白及多糖稳定性，并比较白及多糖对1,1-二苯基-2-苦肼基自由基（DPPH·）和羟基自由基（·OH）的清除率以评价其体外抗氧化活性。结果：最佳超声提取工艺条件为：料液比1:25（g/mL）、超声温度80 ℃、超声时间10 min；四川绵阳白及多糖含量最高，达到60.81%，湖南洪江次之，云南普洱最低；白及多糖在柠檬酸及中性溶液中的稳定性较好，在苯甲酸钠、过酸性或过碱性溶液中的稳定性较差；白及多糖能有效地清除DPPH和羟基自由基，具有潜在的体外抗氧化活性。结论：白及多糖超声波提取工艺的优化及其抗氧化活性研究，可为白及多糖提取及综合利用提供借鉴。     

Serum growth factor stability in different eye drop packaging systems during storage

Serum eye drops (SED) have shown beneficial effects in patients suffering from dry eye syndrome and are manufactured for an increasing number of patients in Australia every year. Previous studies have examined the stability of serum growth factors during storage in either experimental vessels not used as the final packaging system or in eye drop bottles. To ensure the quality and safety of SED product manufactured in Australia, the stability of growth factors in serum packaged into two different systems during storage at different temperatures was examined. Healthy blood donors provided a whole blood donation, from which serum was prepared, diluted to 20% and dispensed into either a tube or a vial packaging system. The stability of growth factors, fibronectin and total protein in tube segments was comparable to matched vials samples during storage at −30 °C, 4 °C, 22 °C and 37 °C, with the exception of EGF and fibronectin in 20% SED stored in tube segments, which were more sensitive to storage conditions at 4 °C and 22 °C when compared to vials. Additionally, the growth factor, fibronectin and total protein concentration in both tube segments and vials was stable during storage at −30 °C for at least 9 months. This study highlights the impact of different manufacturing procedures on serum growth factor stability during storage.     

An investigation of the effects of walking frame height and width on walking stability

BackgroundWalking aids are designed for structural support during walking, however, surprisingly self-reported use of a walking aid (“Yes, I use one.”) has been identified as a risk factor for falling. Adjustment and design of walking aids may affect their usefulness in facilitating a stable walking pattern. We previously identified that increased body weight transfer onto a walking frame (‘device loading’) is associated with increased user stability.Research questionWe asked: “Could adjustment of walking frame height to a lower height than clinically recommended serve as a mechanism to facilitate device loading and thereby increase stability? And: “Do ultra-narrow frames have an adverse effect on stability as compared to standard-width frames?MethodsTen older adults that were users of front-wheeled walking frames walked with walking frames of 1) ‘standard width, standard height’, 2)‘standard width, low height’, 3)‘narrow width, standard height’. Smart Walker technology was used to record forces acting on the walking frame and inside the user’s shoes, and cameras recorded relative position of the user’s feet in relation to the frame’s feet. Stability of the user-frame system and device loading (percent body weight transferred onto the frame) were calculated. A general linear mixed effects model was used for statistical analysis.ResultsA lower height setting did not increase device loading and stability, therefore adjusting the height to a lower setting proved to be an unsuccessful mechanism to increase stability. However, device loading was positively correlated with stability for all frame conditions (p < 0.05). Finally, stability was reduced when walking with the ultra-narrow, as compared to standard-width, frame (p = 0.002).SignificanceTo increase stability in fall-prone users, active encouragement to transfer body weight onto the walking frame is needed. Considering the adverse effects of ultra-narrow frames on stability, such frames should be prescribed and used with caution.     

Stability and synchronization of memristor-based fractional-order delayed neural networks

Global asymptotic stability and synchronization of a class of fractional-order memristor-based delayed neural networks are investigated. For such problems in integer-order systems, Lyapunov–Krasovskii functional is usually constructed, whereas similar method has not been well developed for fractional-order nonlinear delayed systems. By employing a comparison theorem for a class of fractional-order linear systems with time delay, sufficient condition for global asymptotic stability of fractional memristor-based delayed neural networks is derived. Then, based on linear error feedback control, the synchronization criterion for such neural networks is also presented. Numerical simulations are given to demonstrate the effectiveness of the theoretical results.     

Assessment of postural stability in women with hip osteoarthritis: A case–control study

Objective

The aim of the study was to assessment the impact of hip osteoarthritis on postural stability.

Individual analysis of dynamic stability for twenty-four Tai Chi forms among persons with knee osteoarthritis: A pilot study

BackgroundTai Chi (TC) training has been increasingly used to prevent falls. However, the underlying biomechanical mechanisms of TC training which influence fall risk remain unknown. As a result, the selection of TC forms differs among studies, leading to inconsistent results.Research questionIs dynamic stability different between the simplified 24 Yang-style TC forms among adults with knee osteoarthritis?MethodsTen participants with mild to moderate knee osteoarthritis were recruited. Under one-on-one instruction by an experienced TC master, each participant learned how to correctly perform the 24-form TC movements. Participants’ full-body kinematic and kinetic data was collected during walking trials and performance of the respective TC forms. Their dynamic stability was calculated in both sagittal and frontal planes and compared between each TC form and regular walking.ResultsThe results indicate that dynamic stability in both planes significantly varies among forms. Moreover, some forms pose a greater challenge to dynamic stability in comparison to others. The most challenging TC forms are Form 8 for stability in the sagittal plane and Form 10 in the frontal plane. Among all forms, Form 1 appears to be the least challenging.SignificanceOur findings could provide foundational information to identify the best TC forms for optimizing the effectiveness of TC-based fall prevention interventions.     

超微血管成像与超声造影对颈动脉粥样硬化斑块稳定性的诊断价值

目的 探讨超微血管成像（SMI）与超声造影（CEUS）对于颈动脉粥样硬化斑块稳定性的诊断价值。方法 选取2016年1月~2018年6月接受颈动脉内膜斑块剥脱术治疗的61例，术前均行SMI、CEUS检查，检查后7 d内行颈动脉内膜斑块剥脱术治疗。以术后病理检查结果为金标准，分析SMI、CEUS对于颈动脉斑内是否存在新生血管及斑块稳定性的诊断效能。结果 CEUS、SMI对于斑块稳定性的诊断结果与金标准均具有高度一致性（0.8<0.001），对于斑块内新生血管的诊断结果与金标准均具有高度一致性（0.8>     

亚历山大矫正技术减数矫治的稳定性研究

目的探讨亚历山大矫正技术在拔牙矫治中的应用及其效果的稳定性。方法选择15例恒牙患者(男8例,女7例),开始矫治时间10.3~16.2岁。设计减数4个第一前磨牙,采用亚历山大矫正技术,对矫治前(T1)、矫治后(T2)及保持结束后平均27.8个月的观察期(T3)内的模型进行测量。统计学处理采用配对t检验。结果上下尖牙之间的宽度在保持后的回访期内分别减小0.37mm和0.72mm,但P>0.05;虽然上、下颌牙弓排列在回访期内分别有0.53mm和0.98mm的拥挤,但同样无统计学意义。由于内收前牙,矫治后的上、下颌牙弓长度明显减小(P<0.01),在回访期内分别增加0.28mm和0.05mm,但P>0.05。结论初步研究结果表明,亚历山大矫正技术中矫治器设计及其矫正理念有利于拔牙矫正后的稳定。但长期稳定性尚待进一步观察。