Use of a modified ureteral access sheath in semi-rigid ureteroscopy to treat large upper ureteral stones is associated with high stone free rates

Objective:To examine differences in outcomes of semi-rigid ureteroscopy(URS)with or without a modified-ureteral-access-sheath(mUAS)to treat large upper ureteral stones.Methods:Patients with single,radio-opaque large upper ureteral stone(≥10 mm)treated using semi-rigid URS between August 2013 and October 2016 were retrospectively evaluated.The stone-free status was determined from Kidney-ureter-bladder(KUB)X-ray films taken on postoperative Day 1 and after 1 month.Results:Of 103 patients meeting inclusion criteria,43(41.75%)and 60(58.25%)were treated with semi-rigid URS with and without mUAS,respectively.The immediate stone-free rate(SFR)for the mUAS group was significantly higher than the non-mUAS group(40[93.0%]vs.46[76.7%];p=0.033).The SFR at 1 month was also high for patients treated using mUAS,but not statistically different from patients not treated with mUAS(41[95.3%]mUAS vs.51[85.0%]non-mUAS;p=0.115).Auxiliary procedure rates were significantly lower for mUAS patients compared to non-mUAS patients(2[4.7%]vs.14[23.3%];p=0.01).There were no significant differences in surgical duration and hospital stays,and the overall complication rates were statistically similar for mUAS patients compared to non-mUAS patients(1[2.3%]vs.3[5.0%];p=0.638).

STATISTICAL MODELS FOR SEMI-RIGID NEMATIC POLYMERS

Semi-rigid liquid crystal polymer is a class of liquid crystal polymers different from long rigidrod liquid crystal polymer to which the well-known Onsager and Flory theories are applied. Inthis paper, three statistical models for the semi-rigid nematic polymer were addressed. They arethe elastically jointed rod model, worm-like chain model, and non--homogeneous chain model.The nematic-isotropic transition temperature was examined. The pseudo-second transition tem-perature is expressed analytically. Comparisons with the experiments were made and the agree-ments were found.

Static behavior of semi-rigid thin-walled steel-concrete composite beam-to-column joints with bolted partial-depth flush end plate:experimental study

A new type of semi-rigid thin-walled steel-concrete composite beam-to-column joint has been proposed in this paper.Five semi-rigid composite beam-to-column joint specimens subjected to hogging moments under monotonic loading were tested to study the static behavior of this new type of joint.The main variable parameters for the five joint specimens were the longitudinal reinforcement ratio and the joint type.The experimental results designated that the magnitude of extension of the longitudinal reinforcement is the most important factor that influenced the moment-rotation characteristic of the new type of joint.The concrete slabs could resist 3.8%-19.1% of the total shear load applied to the cross-sections near the beam-to-column connection.The edge stiffened elements,such as the flange of the lipped I-section thin-walled steel beam,were capable of having considerable inelastic deformation capacity although they had comparatively large width-to-thickness ratios.The shear failure of the concrete cantilever edge strip must be taken into account in practical design because it has significant influence on the anchorage of the longitudinal reinforcement in the new type of external joints.

Infrapubic versus Penoscrotal Approaches for Implantation of Semi-Rigid Penile Prosthesis

Background: Modification of surgical techniques to minimize wound infections in penile implant surgery using malleable prosthesis which is easy to use, of very low risk of mechanical failure and is financially suitable to improve outcome and ensures less complications. The aim of the study is to compare infrapubic approach and Penoscrotal approach in penile semi-rigid prosthesis implantation surgery. Patients and methods: Fifty patients were randomly divided into two groups and each group underwent one approach. Results: No statically significant differences were found between both groups in terms of operative time. Corporeal cross over was the most common intraoperative complications, 3 cases in IP approach and 6 cases in PS but not statistically significant. Peyronie’s disease patients underwent penile implant through infrapubic approach in 3 cases and PS in 4 cases with one recorded complication of keloid formations with IP. Urethral false passage reported only in one case with PS approach without affecting the procedure. Only minor complications including superficial wound infection which was significantly more with PS, 6/25 (24%) and IP 1/25 (4%), p value = 0.041. Penile and scrotal edema was common with IP approach (92%) in comparison with PS approach (60%). The urethral catheter can be abandoned with IP to avoid the risk of catheterizations. No significant relation between diabetes and infections and no erosions were encountered. Conclusion: Through this research work, infrapubic approach is better than Penoscrotal approach even if it is not commonly used by surgeon.

Study on Test Methods for Mechanical Properties of Semi-rigid Base Cores of In-service Pavements

Compressive strength and compressive resilience modulus are two important parameters to measure the mechanical properties of semi-rigid base.The test methods of semi-rigid base cores are different from those of the laboratory samples in terms of sample acquisition,sample selection and humidity requirements.Core-drilling location,size of core sample,smoothness and humidity conditions were analyzed.The test methods of compressive strength and compressive resilience modulus were proposed.The research results show that compressive strength of lime fly-ash stabilized gravels base has a tendency of increasing during a long period.The compressive resilience modulus increases significantly with compressive strength of semi-rigid base.The compressive resilience modulus generally is 3-4 times than the recommended range of asphalt pavement design specifications.The fluctuation range of compressive resilience modulus is obviously higher than the compressive strength.The compressive resilience modulus is more sensitive to the construction variability.The overall trend between the compressive resilience modulus and the back-calculation modulus is consistent.FWD(falling weight deflectometer)back-calculation modulus can reflect the stiffness and bearing capacity of asphalt pavement.

Semi-Rigid Registration of 3D Points

In this paper, we proposed a method for semi-rigid changed 3D point clouds registration. We first segment the point clouds into individual segments and then the alignment energy costs of each segment are calculated. The rough initial transformation is estimated by minimizing the energy cost using integer programming. The final registration results are obtained by rigid alignments of separated corresponded segments. Experimental result with simulated point clouds demonstrate that the concept of semi-rigid registration works well.

Analytical Model of Nonlinear Semi-rigid Frames Using Finite Element Method

Performance-based design for a constructional steel frame in nonlinear-plastic region requires an improvement in order to achieve a reliable structural analysis.The need to explicitly consider the nonlinear behaviour of structures makes the numerical modelling approach much more favourable than expensive and potentially dangerous experimental work.The parameters considered in the analysis are not limited to the linear change of geometry and material yielding,but also include the effect of large deformations,geometrical imperfections,load eccentricities,residual stresses,strain-unloading,and the nonlinear boundary conditions.Such analysis requires the use of accurate mathematical modelling and effective numerical procedures for solving equations of equilibrium.With that in mind,this paper presents the mathematical formulations and finite element procedures of nonlinear inelastic steel frame analysis with quasi-static semi-rigid connections.Verification and validation of the developed analytical procedures are conducted and good agreements are obtained.It is an approach that enables the structural behaviour of constructional steel frames to be traced throughout the entire range of loading until failure.It also provides information on the derivation of the structural analysis by using finite element method.

Semi-rigid腰椎后路动态钉棒固定系统治疗单节段腰椎不稳的疗效观察

目的探讨Semi-rigid腰椎后路动态钉棒固定系统治疗单节段腰椎不稳的临床疗效。方法对该院2009年6月—2011年1月间采用Semi-rigid腰椎后路动态钉棒固定系统手术治疗34例单节段腰椎不稳症病例进行回顾性分析。结果随访10～24个月,优31例(91.2%),良2例(5.9%),差1例(2.9%),优良率97.1%。结论 Semi-rigid腰椎后路动态钉棒固定系统可有效治疗单节段腰椎不稳,值得临床推广。

Effects of interface slip and semi-rigid joint on elastic seismic response of steel-concrete composite frames

The stiffness matrix of semi-rigidly connected composite beams considering interface slip was established and the calculation method for elastic seismic response of composite frame was derived.The corresponding calculation programs were developed.Introducing the dimensionless quantities that were related to the connector shearing stiffness and the joint rotation stiffness,the influences of interface slip and semi-rigid joint on composite frame were transferred to quantitative parameter analysis,taking account of cross sectional properties,materials and linear stiffness of composite beam synthetically.Based on the calculation programs,free vibration frequencies and seismic responses of semi-rigid joint steel-concrete composite frame considering interface slip were calculated.The influences of interface slip and semi rigid joint on dynamic characteristics and seismic response were analyzed and the seismic design advices were presented.The results show that the interface slip decreases the free vibration frequencies and increase the seismic responses of composite frame.The semi-rigid joint reduces the free vibration frequencies and increases seismic responses of composite frame compared with rigid joint.With the increase of joint rotational stiffness,the elastic seismic responses of composite frame increase firstly and then decrease.The effects are related to the ratio of joint rotation stiffness to linear stiffness of composite beam.

Compressive strength and frost heave resistance of different types of semi-rigid base materials after freeze-thaw cycles

Freeze-thaw damage is the most common disease of semi-rigid bases in cold regions, which may greatly affect the durability of roadways. In this study, the compressive strength and frost resistance of four different types of semi-rigid bases(lime-fly ash-stabilized sand, cement-stabilized sand, lime-fly ash-stabilized gravel, and cement-stabilized gravel) are assessed by varying the materials content. Based on freeze-thaw and compressive strength tests, this paper presents the performance of the different materials, each having different physical properties, and the optimal amounts of materials contents are proposed.

Effects of temperature change on elastic behavior of steel beams with semi-rigid connections

Based on the nonlinear displacement-strain relationship,the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change.Considering the non-uniform temperature distribution across the thickness of beams,the formulas for stresses and vertical displacements were presented.On the basis of a flowchart for analysis of the numerical example,the effect of temperature change on the elastic behavior of steel beams was investigated.It is found that the maximal stress is mainly influenced by axial temperature change,and the maximal vertical displacement is principally affected by temperature gradients.And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints.Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints.It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant.However,the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.

Progressive Collapse Analysis of Concrete-Filled Steel Tubular Frames with Semi-rigid Connections

A 9-story concrete-filled steel tubular frame model is used to analyze the response of joints due to sudden column loss. Three different models are developed and compared to study the efficiency and feasibility of simulation, which include substructure model, beam element model and solid element model. The comparison results show that the substructure model has a satisfying capability, calculation efficiency and accuracy to predict the concerned joints as well as the overall framework. Based on the substructure model and a kind of semi-rigid connection for concretefilled square hollow section steel column proposed in this paper, the nonlinear dynamic analyses are conducted by the alternate path method. It is found that the removal of the ground inner column brings high-level joint moments and comparatively low-level axial tension forces. The initial stiffness and transmitted ultimate moment of the semi-rigid connection are the main factors that influence the frame behavior, and their lower limit should be guaranteed to resist collapse. Reduced ultimate moment results in drastic displacement and axial force development, which may bring progressive collapse. The higher initial stiffness ensures that the structure has a stronger capacity to resist progressive collapse.

Prospective randomized study to evaluate and compare the post-procedural sexual function in patients undergoing semi-rigid ureterorenoscopy for distal ureteric stones in three different operating room settings

Objective:To evaluate and compare the effect of semi-rigid ureterorenoscopy on post-procedural sexual function with three different operating room settings.Methods:In this prospective randomized study,consecutive sexually active patients with normal pre-operative sexual function undergoing uncomplicated semi-rigid ureterorenoscopy for distal ureteric stones were randomized into three groups,with three different operating room settings.Procedure-related anxiety and sexual function were assessed pre-operatively using Amsterdam Preoperative Anxiety and Information Scale and Brief Sexual Function Inventory(in males)and Female Sexual Function Index-6(in females),respectively.All the participants were stented following the procedure,and the stent was removed after 3 weeks.Post-procedural sexual function and general discomfort were assessed and compared between three groups at 1 week,3 weeks,and 12 weeks.The effect of surgery-related anxiety,preoperative sexual function,age,and general discomfort(including stent-related discomfort)on post-procedural sexual function were analyzed using multiple regression analysis.A p-value of less than 0.05 was considered statistically significant.Results:Totally,327 eligible patients were randomized into three groups.The group of patients who underwent the procedural with a screen separating the operating area from the patient vision,while the patient could watch the endoscopy through a separate monitor,had better post-procedural sexual function compared to those who had total vision of the operating area as well as to those whose eyes were blocked.This difference was statistically significant.This post-procedural reduction in sexual function could not be attributed to in situ stent alone.Conclusions:Our study showed that semi-rigid ureterorenoscopy can have significant negative effect on sexual function,which can be reduced with proper preoperative counseling and an ideal operating room settings.

Semi-rigid动态系统治疗腰椎滑脱症的疗效分析

目的观察腰椎后路semi-rigid动态内固定系统治疗腰椎滑脱症的疗效。方法回顾性分析32例腰椎退行性变患者的临床资料。按Newman分型:峡部滑脱18例,退行性滑脱14例,所有患者均行手术减压、腰椎后路semi-rigid动态内固定系统固定。分析术后Oswestry功能障碍指数评分(ODI)和日本骨科学会评分(JOA)改善情况,随访临床疗效及影像学观察结果。结果术后1年,ODI分值较术前下降[(12.15±5.27)分vs.(61.82±10.79)分](P<0.05),JOA分值较术前提高[(27.89±1.99)分vs.(9.28±1.86)分](P<0.05)。术后1年动态固定邻近节段退变椎间盘有逆退变过程演变的趋势。结论腰椎后路semi-rigid动态内固定系统是治疗腰椎滑脱症的有效方法,可预防和减少融合相邻节段的椎间盘退变。

单边螺栓连接中心支撑钢框架抗震性能分析

目的为研究支撑-半刚接钢框架结构体系的抗震性能,方法设计了一榀由嵌套式单边螺栓与T型钢构成的半刚性梁柱节点的中心支撑钢框架,并进行了拟静力试验与有限元数值模拟,通过观测整个试验现象,分析了其滞回、承载力、刚度退化、耗能等抗震指标。结果结果表明:试件破坏过程明显经历了弹性段、塑性段、破坏段三个阶段,试件破坏模式主要为支撑受压失稳破坏,塑性变形主要累积在支撑体系上,整体呈现延性破坏特征;支撑断裂后,梁柱及T型钢节点无明显塑性变形,钢框架仍具有较高的安全储备,符合“强节点、弱构件”设计原则,表明了结构具有两道抗震防线;结论支撑与半刚接钢框架协同工作使得试件具有较高的抗侧刚度抵抗水平变形,且承载力较高、滞回性能稳定、耗能能力优良;单边螺栓在试验过程中的受力性能较普通高强螺栓并无较大差别,未出现严重的预紧力松弛现象,并能高效的保持螺栓预紧力。通过有限元数值模拟分析可知,减小支撑长细比,虽能有效提高结构的抗震性能,但长细比较小会导致支撑刚度增大,加速其余构件的损坏。故应以考虑结构的延性为前提,降低支撑的长细比,才能有效提高结构的抗震性能。

Ureteroscopy with Holmium: YAG Laser—A Initial Study in the Urology Department of the Pr Bocar Sidy Sall University Hospital of Kati

Introduction: Ureteroscopy is a minimally invasive endoscopic surgery which provides access to the ureter, pyelon and calyceal cavities via the urethra and the bladder. Laser ureteroscopy uses the laser as an energy source to treat the stone and eliminate it naturally. Minimally invasive endoscopic methods are struggling to become popular in sub-Saharan African countries, especially for the upper urinary tract. The objective of our work was to report the results of our first laser ureteroscopy experience in the department. Materials and Methods: This was a prospective and descriptive study running from December 1, 2023 to February 19, 2024. Included in our study was any case of upper urinary tract stone operated by Laser ureteroscopy. The characteristics of the lithiasis were determined by CT scan. Sterilization of urine was verified by carrying out a cytobacteriological examination of urine. Ureteral lithiasis was approached by semi-rigid ureteroscopy. Renal lithiasis was immediately addressed by flexible ureteroscopy. Ureteroscopy was coupled with a Holmium YAG laser. A double J ureteral catheter was placed after the operation. A 230 µm laser fiber was used in each case with a generator with a power of 35 watts (Storz Calculase III type). An access sheath was used in all cases of flexible ureteroscopy. The parameters studied were: sociodemographic characteristics, lithiasis (site, size, number, density, topography), type of anesthesia, duration of laser use, duration of intervention, postoperative outcomes. Data entry and analysis were carried out using the software (Word 2016 and SPSS). Result: We collected 30 cases of laser ureteroscopy. The average age was 37 years with extremes of 9 and 79 years. The male gender was more represented. The most common age group was 24-39 years old. Renal colic was the most frequent reason for admission, 12 patients (40%). On physical examination, lumbar tenderness was present in 47% (14 patients). ECBU was positive in 4 patients (13%). CT scan was performed in all our patients before the intervention. The average stone size was 12 mm and the largest was 23 mm. The majority of stones, i.e. 59% (18 patients), had a density greater than 1000 HU. The stone was unique in 19 patients (63%). The location of the stone was pyelic in 8 patients or 27%. An impact on the upper urinary tract was found in 16 of our patients or 53%. General anesthesia was used in 25 patients (83%). A digital flexible ureteroscopy was used in 24 patients and a semi-rigid ureteroscopy (URS) in 6 patients. Full-course fragmentation was the most used therapeutic method, 9 patients or 32%. The average duration of interventions was 61 minutes. Drainage by double J catheter at the end of the procedure was performed in all our patients. The length of hospitalization was 24 hours. Only one case of failure in the USSR was recorded, and one case of failure was in the semi-rigid URS. Conclusion: Laser ureteroscopy is an effective minimally invasive surgery in the management of lithiasis of the upper urinary tract. It significantly reduces the length of hospitalization. Mastery of this technique and the acquisition of the equipment necessary for its implementation is an undeniable asset in the management of renal and ureteral lithiasis.

基于代理模型的输电塔半刚性节点弯矩-转角曲线预测方法

为了准确、高效地评估输电塔半刚性节点的力学特性,提出了一种基于代理模型的输电塔半刚性节点弯矩-转角曲线预测方法,通过引入代理模型方法近似半刚性节点几何尺寸与极限抗弯承载力、初始转动刚度之间的函数关系,建立具有较高精度的预测模型,进而结合Kish-Chen幂函数模型拟合输电塔半刚性节点的弯矩-转角曲线。结果表明,提出的基于代理模型的输电塔半刚性节点弯矩-转角曲线预测方法能减少实验和数值模拟的成本,较好地模拟输电塔半刚性节点实际受力-变形情况,为输电塔半刚性节点的工程设计和理论研究提供了参考。

原竹抱口梁柱节点抗弯性能研究

竹材作为一种新型的绿色环保建筑材料,梁柱连接是现代竹结构推广需要考虑的重要问题。为了丰富原竹节点的形式,探究不同构造措施下梁柱节点的刚度和承载力,设计制作了3种形式的原竹抱口梁柱连接节点,按照金属连接件构造的不同命名为简易钢夹节点J1、贯通螺栓节点J2和自攻螺钉节点J3。每一种节点内部依据不同原竹等级设计3组试件,通过单调加载试验,探究节点弯曲力学性能及破坏特征,得到了3种节点的弯矩-转角曲线。基于弯矩-转角曲线变化特征,提出三折线刚度分析模型拟合节点分段刚度参数值,应用欧洲钢结构规范节点类型判别方法,对节点的半刚性程度进行了验证。结果显示:贯通螺栓节点J2和简易钢夹节点J1属于半刚性节点;自攻螺钉节点J3属于铰节点。研究表明:原竹等级对于简易钢夹节点J1和自攻螺钉节点J3的抗弯性能影响不敏感;对于贯通螺栓节点J2的抗弯性能影响显著,等级为T8时与连接件的协同工作性能最优。研究成果可为现代竹结构应用提供理论依据。

基于截尾分布的永久路面结构可靠度分析

为建立基于实测参数变异范围的永久路面结构可靠度分析方法,首先基于概率等效原则和逆变换法建立参数“有界”性的双侧截尾分布随机数抽样方法;然后选取现行沥青路面设计规范中面层、基层和路基结构的验算指标建立极限状态方程并开发多指标可靠度计算程序,将分析结果与理论分布随机变量可靠度程序对比;最后结合实测参数变异性水平,使用建立的可靠度分析方法评估京德高速永久路面结构的工后可靠度。结果表明:截尾分布更符合工程参数的真实分布,计算的可靠度更准确;中等交通荷载等级下,京德高速的路面结构可靠度为95.2%~98.7%;在累计当量轴次失效点后,永久路面结构面层、基层和路基的可靠度值均随轴次的增大而减小,且荷载越大,可靠度值下降速率越快,可靠度也越低。