Stability characteristics of ring-stiffened cylindrical shells under different longitudinal and transverse external pressures

Because ring-stiffened cylindrical shell structures have many merits, they are widely used in many areas. However, as the strength of steel increase continuously, ensuring of the structure stability is becoming more and more important. Therefore, it is necessary to carry on a more particular analysis. Based on the understanding and analysis of the characteristics of stability for a ring-stiffened cylindrical shell under uniform external pressure and under external single pressure, the characteristics under different cross uniform external pressures are analyzed, and the regularity of it is also gotten. The curve of stability given various geometrical parameters under different cross uniform external pressures is protracted by the analysis of the theory. The conclusion not only improves the theory structural mechanics, it also was important effects on engineering calculation and design.

Cartilage Repair by Joint Distraction and Motion Using an External Fixator for Massive Cartilage Defect

The objective of the present study was to investigate our novel methods for the repair of massive cartilage defects by joint distraction and motion using an external fixator. In this study, we used a rabbit model of massive articular cartilage defect in order to evaluate the effectiveness of using joint distraction and motion with a ring-type external fixator. This external fixator has a hinged joint with a center of rotation along the femoral transepicondylar axis, which allows the knee joint to freely flex and extend. Mesenchymal cells from bone marrow, induced by spongialization, were differentiated into mature chondrocytes and formed hyaline-like cartilage as a result of joint distraction and movement. The transplantation of autologous cells expanded from bone-marrow-derived mesenchymal cells, concentrated autologous bone marrow aspirate, and concentrated autologous peripheral blood cells were all effective in promoting cartilage repair. The quality of the cartilage after long-term joint distraction for 6 months was inferior to that after 12 weeks. In general, weight bearing on the regenerated cartilage promoted cartilage repair, although this effect differed based on when gradual weight bearing was begun. Specifically, gradual weight bearing beginning at 9 weeks produced superior results to that beginning at 6 weeks. Our methods provide an optimal environment for cartilage regeneration.

Formation process of extension knee joint contracture following external immobilization in rats

BACKGROUND Current research lacks a model of knee extension contracture in rats.AIM To elucidate the formation process of knee extension contracture.METHODS We developed a rat model using an aluminum external fixator.Sixty male Sprague-Dawley rats with mature bones were divided into the control group(n=6)and groups that had the left knee immobilized with an aluminum external fixator for 1,2,and 3 d,and 1,2,3,4,6,and 8 wk(n=6 in each group).The passive extension range of motion,histology,and expression of fibrosis-related proteins were compared between the control group and the immobilization groups.RESULTS Myogenic contracture progressed very quickly during the initial 2 wk of immobilization.After 2 wk,the contracture gradually changed from myogenic to arthrogenic.The arthrogenic contracture progressed slowly during the 1^(st) week,rapidly progressed until the 3^(rd) week,and then showed a steady progression until the 4^(rd) week.Histological analyses confirmed that the anterior joint capsule of the extended fixed knee became increasingly thicker over time.Correspondingly,the level of transforming growth factor beta 1(TGF-β1)and phosphorylated mothers against decapentaplegic homolog 2(p-Smad2)in the anterior joint capsule also increased with the immobilization time.Over time,the cross-sectional area of muscle fibers gradually decreased,while the amount of intermuscular collagen and TGF-β1,p-Smad2,and p-Smad3 was increased.Unexpectedly,the amount of intermuscular collagen and TGF-β1,p-Smad2,and p-Smad3 was decreased during the late stage of immobilization(6-8 wk).The myogenic contracture was stabilized after 2 wk of immobilization,whereas the arthrogenic contracture was stabilized after 3 wk of immobilization and completely stable in 4 wk.CONCLUSION This rat model may be a useful tool to study the etiology of joint contracture and establish therapeutic approaches.

Numerical Analysis of Local Joint Flexibility of K-joints with External Plates Under Axial Loads in Offshore Tubular Structures

The Local Joint Flexibility(_(LJF))of steel K-joints reinforced with external plates under axial loads is investigated in this paper.For this aim,firstly,a finite element(FE)model was produced and verified with the results of several experimental tests.In the next step,a set of 150 FE models was generated to assess the effect of the brace angle(θ),the stiffener plate size(ηandλ),and the joint geometry(γ,τ,ξ,andβ)on the_(LJF)factor(f_(LJF)).The results showed that using the external plates can decrease 81%of the f_(LJF).Moreover,the reinforcing effect of the reinforcing plate on the f_(LJF)is more remarkable in the joints with smallerβ.Also,the effect of theγon the f_(LJF)ratio can be ignored.Despite the important effect of the f_(LJF)on the behavior of tubular joints,there is not available any study or equation on the f_(LJF)in any reinforced K-joints under axial load.Consequently,using the present FE results,a design parametric equation is proposed.The equation can reasonably predict the f_(LJF)in the reinforced K-joints under axial load.

Influence of flash trap profiles on joint properties of friction welded CP-Ti tube to 304L stainless steel tube plate using external tool

Titanium tube and stainless steel tube plate were welded by an innovative friction welding of tube to tube plate using an external tool (FWTPET). Copper was used as an interlayer for joining the dissimilar materials and also to minimize the effect of intermetallics formed at the joint interface. The process parameters that govern FWTPET process are plunge rate, rotational speed, plunge depth, axial load and flash trap profile. Among them, the flash trap profile of the tube has a significant influence on the joint integrity. Various flash trap profiles like vertical slots, holes, zig-zag holes, and petals were made on the titanium tube welded to the stainless steel tube plate. Macroscopic and microscopic studies reveal defect-free joints. The presence of copper interlayer and intermetallics was evident from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) studies. The microhardness survey was presented across and along the interface. A novel test procedure called “plunge shear test” was developed to evaluate the joint properties of the welded joints. The highest shear fracture load of 31.58 kN was observed on the sample having petals as flash trap profile. The sheared surfaces were further characterized using SEM for fractography.

Qatar steps up to Global Health security:a reflection on the joint external evaluation,2016

Since the commencement of the International Health Regulations in 2007,global public health security has been faced with numerous emerging and ongoing events.Moreover,the Joint External Evaluation is a voluntary tool developed in compliance with the Global Health Security Agenda that represents the high responsibility of international health community towards the increased incidence of emerging and re-emerging diseases.Against this background,between 29th May and 2nd June 2016,a team of World Health Organization consultants arrived to the State of Qatar to assess,in collaboration with national experts,the country’s capacity to prevent,detect,and rapidly respond to threats of public health aspect.They identified areas of strength,weakness,and recommendations for improving national health security of Qatar in anticipation of the 2022 FIFA World Cup event.Qatar has demonstrated a leading role in the region through its commitment to International Health Regulations(2005)and population health.Similarly,the Qatar was the first Arab state and seventh volunteering country globally to undergo the Joint External evaluation process.In this review,we highlighted Qatar’s achievements and shortcomings of International Health Regulations’core capacities to inform healthcare professionals and the scientific community about the country’s contribution toward global health security.

Closed External Subtalar Dislocation: A Case Report

Subtalar dislocation is described as the simultaneous dislocation of the talo-calcaneal and talo-navicular joints without any tibio-talar or talar neck associated fractures. This injury is rare, and represents 1% of dislocations. We report the case of 28-year-old male patient, without any medical history, who had been involved in a sport accident causing a rare closed external subtalar dislocation without any bone fracture. An open reduction was indicated after failure of closed reduction and the X-ray control showed good joint congruence;the fixation was maintained for 6 weeks and then the rehabilitation was started. The evaluation was favorable, and we noted good functional results after a decline of 12 months.

Strength calculation methodology for internally ring- stiffened DT- joints

In order to obtain the strength design equations for internally ring-stiffened circular hollowsection tubular DT（ double tee）-joints subjected to brace axial compression or tension, theoretical and numerical studies on 800 stiffened joints were conducted. Based on the failure mechanism of the stiffened joints, four theoretical models and corresponding equations for predicting the strength of the stiffeners are proposed. Combined with existing unstiffened DT-joint design equations, a design equation for the stiffened joints is proposed. The finite element analysis shows that the failure of the stiffened joints under brace axial loads can be characterized by plastic hinges forming in the stiffener and chord wall yielding in the vicinity of the brace-chord intersection. The reliability of the proposed stiffener strength equations is demonstrated by a reliability analysis. Good agreement is achieved between the stiffened joint strength calculated from the proposed joint strength equation and that obtained from finite element analysis.

Knowledge-enriched joint-learning model for implicit emotion cause extraction

Emotion cause extraction(ECE)task that aims at extracting potential trigger events of certain emotions has attracted extensive attention recently.However,current work neglects the implicit emotion expressed without any explicit emotional keywords,which appears more frequently in application scenarios.The lack of explicit emotion information makes it extremely hard to extract emotion causes only with the local context.Moreover,an entire event is usually across multiple clauses,while existing work merely extracts cause events at clause level and cannot effectively capture complete cause event information.To address these issues,the events are first redefined at the tuple level and a span-based tuple-level algorithm is proposed to extract events from different clauses.Based on it,a corpus for implicit emotion cause extraction that tries to extract causes of implicit emotions is constructed.The authors propose a knowledge-enriched jointlearning model of implicit emotion recognition and implicit emotion cause extraction tasks(KJ-IECE),which leverages commonsense knowledge from ConceptNet and NRC_VAD to better capture connections between emotion and corresponding cause events.Experiments on both implicit and explicit emotion cause extraction datasets demonstrate the effectiveness of the proposed model.

中药外敷联合复合超声关节治疗仪治疗膝骨关节炎的临床效果

目的探究中药外敷联合复合超声关节治疗仪在膝骨关节炎(KOA)中的应用效果。方法选取2022年8月至2023年8月就诊于安阳市中医院的99例KOA患者为研究对象,随机分为3组,每组33例。超声组接受超声关节治疗仪治疗,中药组接受中药外敷治疗,联合组接受中药外敷联合超声关节治疗仪治疗。对比3组疗效及治疗前后西安大略和麦克马斯特大学骨关节炎指数(WOMAC)、视觉模拟评分法(VAS)、奎森功能演算(Lequesne)指数评分、成纤维细胞生长因子2(FGF-2)、Ⅰ型胶原C-末端肽(CTX-I)、软骨寡聚基质蛋白(COMP)及不良反应。结果联合组总有效率[93.94%(31/33)]高于超声组[75.76%(25/33)]、中药组[72.73%(24/33)](P<0.05),超声组与中药组总有效率对比,差异无统计学意义(P>0.05);治疗3个疗程后联合组FGF-2高于超声组、中药组,CTX-1、COMP、Lequesne、WOMAC评分低于超声组、中药组(P<0.05),超声组、中药组组间对比,差异无统计学意义(P>0.05);治疗3个疗程后联合组静态、动态VAS评分<中药组<超声组(P<0.05);治疗期间3组均未出现不良反应。结论中药外敷与复合超声关节治疗仪联合治疗KOA患者效果确切,可有效调节骨代谢指标,有助于缓解患者疼痛感,恢复膝关节功能。

早期应用跨关节外固定支架对胫骨平台骨折患者膝关节软组织的保护效果

目的 探讨早期应用跨关节外固定支架治疗,对Ⅵ型胫骨平台骨折患者膝关节软组织的保护效果。方法 选取2019年1月至2020年12月收治的Ⅵ型胫骨平台骨折患者122例为研究对象,以信封法进行随机分成研究组和对照组,每组61例。研究组患者给予早期(收治12 h内)跨关节外固定支架联合内固定手术;对照组患者给予延期(收治24~72 h内)跨关节外固定支架联合内固定手术。观察和比较2组患者的手术情况指标、术后恢复指标、膝关节疗效、膝关节功能评分、膝关节软组织损伤指标。结果 研究组外固定手术时间和内固定手术时间均短于对照组,外固定术后VAS评分低于对照组,内固定术中出血少于对照组;研究组康复时间和骨折愈合时间均短于对照组,差异均有统计学意义(P<0.05);2组并发症发生率和膝关键治疗优良率比较,差异无统计学意义(P>0.05);术后,2组患者各项膝关节功能评分均降低,且研究组低于对照组,差异均有统计学意义(P<0.05);研究组外固定术后水疱发生率低于对照组,外固定术后肿胀程度小于对照组,水疱痂皮愈合时间早于对照组,差异均有统计学意义(P<0.05)。结论 与延期时机相比,给予Ⅵ型胫骨平台骨折患者早期跨关节外固定支架联合内固定手术治疗,能够缩短手术时间,提升患者骨折愈合和术后康复进程,促进患者膝关节功能和膝关节软组织损伤的恢复。

随机噪声平板下光学复眼内外参联合标定

光学复眼在无人系统的精确定位制导、避障导航等任务中得到了越来越广泛的应用,其中光学复眼的高精度标定是保障上述任务质量的前提。通常经典的张氏棋盘格标定法要求光学复眼的每个子眼都必须观测到完整的棋盘格,然而,由于光学复眼结构的复杂性,在实际标定过程中难以满足这一要求。为解决张氏标定法的局限性,该文提出一种基于随机噪声平板的光学复眼内外参联合标定算法,该算法通过子眼拍摄随机噪声平板的局部信息,可简单快速地实现任意构型和子眼数量的光学复眼内外参联合标定。为了提高光学复眼标定的稳定性,设置多阈值匹配机制解决子眼视场特征点数量稀疏导致图像匹配失效的问题。同时,给出了光学复眼内外参联合标定的误差模型,用来衡量所提出算法的精确度。在与张氏棋盘格标定法进行实验对比中,验证所提算法的稳定性和鲁棒性,并在光学复眼实物系统中,验证了所提联合标定算法具有较高的精度。

铍针结合三七散外敷治疗肱二头肌长头腱鞘炎疗效及对患者肌骨超声参数、血清炎症因子、肩关节功能的影响

目的:探讨铍针结合三七散外敷治疗肱二头肌长头腱鞘炎效果及对患者肌骨超声参数、血清炎症因子、肩关节功能的影响。方法:80例肱二头肌长头腱鞘炎患者随机分为对照组与观察组,各40例。对照组采用放射式冲击波治疗,观察组则实施铍针结合三七散外敷治疗,均连续治疗4周。比较两组临床疗效,治疗前后两组患者疼痛情况[视觉模拟疼痛评分(VAS)、压痛阈值(PPTs)]、肩关节功能[Constant-Murley肩关节功能活动评分量表(CMS)]、肌骨超声参数(肌腱厚度、腱鞘厚度、积液最大径)、血清炎症因子[肿瘤坏死因子-α(TNF-α)、C反应蛋白(CRP)、白细胞介素-6(IL-6)]的变化。结果:观察组患者临床疗效87.50%,明显高于对照组的67.50%(P<0.05);治疗后,观察组VAS评分低于对照组,观察组PPTs值高于对照组(P<0.05);观察组肌力、疼痛、肩关节活动度及功能评分均高于对照组(P<0.05);观察组肌腱厚度、腱鞘厚度、积液水平均低于对照组(P<0.05);观察组血清TNF-α、CRP、IL-6水平均低于对照组(P<0.05)。结论:铍针结合三七散外敷治疗肱二头肌长头腱鞘炎可提高临床效果,减轻患者疼痛,提高疼痛阈值,同时可降低患者血清炎症因子水平,改善肌骨超声参数和肩关节功能。

错层位外错式巷道位置选择及联合支护研究

针对新巨龙煤矿1301综放工作面区段间留设煤柱尺寸较大造成的资源浪费和回采巷道支护困难等问题,本文提出采用错层位外错式巷道布置方案,建立错层位非常规煤柱力学模型,利用极限平衡理论分析了非常规煤柱应力环境和极限平衡区特征;考虑不同错距下沿底巷道所处应力环境及区段煤柱弹性应变能密度分布特征,确定下区段沿底巷道合理错距为3.0 m;同时引入区段间相邻巷道联合支护方案,对实际地质条件下接续工作面回采阶段区段间相邻巷道联合支护方案和传统支护方案进行模拟验证。结果表明:区段间相邻巷道联合支护方案优于传统支护方案,峰值应力由80 MPa降至64 MPa,降低率为20%,表明其对巷道围岩控制更为有效;区段煤柱单位留设面积为111.5 m^(2),相较于传统支护方案区段煤柱的170 m^(2),降低率为34.4%。研究结果对减少区段煤柱留设尺寸和提高煤炭回采率起到积极的推动作用。

手法复位小夹板外固定结合红白舒筋散治疗桡骨远端骨折的临床观察

目的 探讨手法复位小夹板外固定结合红白舒筋散治疗桡骨远端骨折的临床疗效。方法 选取2021年1月-2022年6月本院收治的80例桡骨远端骨折患者,按照随机数表法分为观察组与对照组,各40例。对照组以手法复位小夹板外固定治疗,观察组在对照组治疗基础上增加红白舒筋散外敷治疗。连续治疗1个月后评估2组的症状消退时间、骨折愈合时间、腕关节活动度、治疗安全性。结果 观察组症状包括疼痛、肿胀、畸形、瘀血消退、骨折愈合时间均短于对照组(P<0.05)。观察组腕关节活动度均高于对照组(P<0.05)。观察组满意度高于对照组(P<0.05)。2组不良反应发生率无统计学意义(P>0.05)。结论 红白舒筋散外敷结合手法复位小夹板外固定治疗桡骨远端骨折的效果良好,可促进患者症状消退,缩短骨折愈合时间,改善患者的腕关节活动度,降低炎症因子水平,改善血液流变学指标,治疗安全性良好。

早期制动配合外敷消炎止痛软膏治疗急性踝关节扭伤的疗效观察

目的评价早期制动配合外敷消炎止痛软膏治疗急性踝关节扭伤的疗效。方法纳入2019年2月至2021年12月从我院收治的急性踝关节扭伤患者84例进行研究,按照随机分组,每组各42例。对照组接受早期制动措施,观察组接受早期制动联合外敷消炎止痛软膏治疗,对比评价两组患者的治疗效果、踝关节功能评分、中医证候积分、生活质量。结果治疗后,相较于对照组(83.33%),观察组患者的总有效率(97.62%)更高(P<0.05);治疗后观察组患者的疼痛评分、功能评分、对线评分均比对照组高,差异有统计意义(均P<0.05);观察组患者生活质量评分高于对照组,而中医证候积分低于对照组(均P<0.05)。结论临床治疗急性踝关节扭伤尽早实施制动处理联合外敷消炎止痛软膏能有效缓解患者的踝关节疼痛和不适症状,还能显著提高踝关节功能恢复,促进患者尽早恢复。

外部能场辅助搅拌摩擦焊接技术综述

外部能场辅助搅拌摩擦焊接是一种改进型固相焊接方法,在航空航天、汽车制造、能源领域等方面得到了广泛应用,通过引入外部能场,可以改善焊接接头的组织和性能,提高焊接质量和效率。本文对外部能场辅助搅拌摩擦焊接技术进行了分类,综述了能场的选择和控制、工艺参数的优化等,阐述了外部能场对焊接温度、轴向载荷、接头组织性能的影响,最后总结了外部能场辅助搅拌摩擦焊接技术未来的发展趋势。

同伴支持护理模式用于踝关节马蹄畸形外支架固定术后的效果

目的分析同伴支持护理模式在踝关节外支架固定术后的应用价值。方法选择2017年1月~2018年12月在我院骨科接受踝关节外支架固定术的马蹄足患者92例,其中2017年1月~2017年12月(同伴支持模式实施前)收治的50例纳入对照组,为常规术后处理;2018年1月~2018年12月(实施后)收治的42例纳入观察组,为同伴支持护理模式。比较两组应用效果。结果观察组患侧踝关节恢复中立位时间、弃拐正常行走时间较对照组短(P<0.05);干预后视觉模拟疼痛(VAS)评分低于对照组,美国矫形足踝协会(AOFAS)评分、住院满意度评分高于对照组(P<0.05);并发症发生率无统计学差异(P>0.05)。结论常规护理结合同伴支持护理模式更利于踝关节外支架固定术患者术后恢复,患者住院满意度更高。

关节腔靶向注射臭氧联合中药外敷治疗早期类风湿关节炎膝关节病变的临床研究

目的:探究关节腔靶向注射臭氧联合中药外敷治疗早期类风湿关节炎膝关节病变的临床效果。方法:回顾性选取九江市第一人民医院2022年6月—2023年9月收治的80例早期类风湿关节炎膝关节病变患者,根据治疗方案将其分为联合组(n=47)和对照组(n=33),对照组采用临床常规治疗方案,即采用曲安奈德进行关节腔注射治疗,联合组采用关节腔靶向注射臭氧联合中药外敷治疗。均治疗3周。比较两组疗效;比较两组治疗前后的C反应蛋白(CRP)、抗环瓜氨酸多肽抗体(ACCP)、类风湿因子(RF)和甘露聚糖结合凝集素(MBL)水平;比较两组治疗前后的视觉模拟评分法(VAS)评分及关节超声评估情况。结果:联合组总有效率为93.62%,高于对照组的72.73%,差异有统计学意义(P<0.05)。治疗后,两组血清RF、CRP、ACCP水平均低于治疗前,且联合组均低于对照组;两组血清MBL水平均高于治疗前,且联合组高于对照组,差异均有统计学意义(P<0.05)。治疗后,两组髌上囊积液深度、髌上囊滑膜厚度、VAS评分均低于治疗前,且联合组均低于对照组,差异均有统计学意义(P<0.05)。结论:关节腔靶向注射臭氧联合中药外敷治疗早期类风湿关节炎膝关节病变的效果较好,可以显著改善患者的血清学指标和疼痛程度,并减轻膝关节病变。

手法复位夹板外固定和闭合骨折复位内固定治疗儿童闭合性肱骨髁上骨折的效果对比研究

对比手法复位夹板外固定和闭合骨折复位内固定治疗儿童闭合性肱骨髁上骨折的效果。选取2020年1月—2021年12月广东省佛山市中医院收治的242例闭合性肱骨髁上骨折患儿为研究对象,根据治疗方法的不同将患儿分为两组,分别为对照组(n=52)和观察组(n=190)。对照组患儿接受手法复位夹板外固定手术治疗,观察组患儿接受闭合骨折复位内固定手术治疗,比较两组患儿治疗效果。结果显示,观察组患儿各项关节功能评分均高于对照组(P<0.05),并发症总发生率低于对照组(P<0.05),疼痛评分低于对照组(P<0.05),住院时间短于对照组(P<0.05)。研究发现,在儿童闭合性肱骨髁上骨折手术治疗中,闭合骨折复位内固定手术治疗法所取得的治疗效果显著优于手法复位夹板外固定治疗法,其更有助于改善患儿关节功能,预防并发症的出现,减轻患儿疼痛感,促进患儿骨折愈合。