产科因素对压力性尿失禁的发生及盆底肌力的影响

目的：探讨不同产科因素对压力性尿失禁的发生和盆底肌力的影响。方法采用国际尿控协会推荐的国际尿失禁标准问卷,对701例在新疆医科大学第一附属医院产科分娩并进行产后复查的初产妇进行问卷调查,按分娩方式分为阴道妥娩组（161例）和选择性剖宫产组（540例）,了解其孕期及产后6 w 尿失禁的发生情况,并测定盆底肌肉收缩及舒张功能,分析与尿失禁发生及影响盆底肌力有关的产科因素。结果701例产妇中有42例（5．99％）在产后6 w 左右出现了尿失禁症状;产后尿失禁的发生与分娩方式、新生儿体质量、孕前体质量、体质指数相关（P ＜0．05）;阴道分娩组、选择性剖宫产组的尿失禁发生率分别为11．18％（18/161）、4．44％（24/540）,两组差异有统计学意义（P ＜0．05）;阴道分娩组中与产后尿失禁发生有关的因素有新生儿体质量、孕前体质量和体质指数（P ＜0．05）,而与孕周、年龄、第二产程时间均无明显相关性。阴道分娩组的产后盆底肌力检测数值低于选择性剖宫产组,差异有统计学意义（P ＜0．05）。结论阴道分娩、新生儿体质量、孕前体质量、体质指数增加与产后压力性尿失禁的发生有关;阴道分娩、选择性剖宫产2种分娩方式均影响产后盆底肌力,阴道分娩可以明显降低产后盆底肌力。     

两种玻璃离子水门汀主要性能的试验研究

目的探讨临床常用的通用型玻璃离子和3M公司的Ketac Molar玻璃离子及Dentsply生产的Chemill SUPERIOR无液配方玻璃离子的粘接性能和机械性能及粘接面的粗糙程度对粘接性能的影响：方法①应用XL-50A拉力实验机测试三种材料在不同粗糙牙本质表面的抗剪切力值,比较三种材料的抗剪切性能及粗糙程度对粘接性能的影响：②用ZDM-20型液压万能实验机测试三种材料在标准条件下的抗压强度。结果无论是普通型、3M型还是无液型水门汀,其裂钻组和抛光组抗剪切强度都有高度显著性差异（P〈0．01）,抛光组抗剪切强度明显高于裂钻组抗剪切强度（P〈0．01）;裂钻组或抛光组,无液型的抗剪切强度明显高于3M型（P〈0．01）：结论①对于牙本质的抛光,可使粘接力明显提高;②相对于通用型玻璃离子,无液型GIC较常用型玻璃离子水门汀在粘接性能上有较大提高,3M后牙玻璃离子则在机械性能方面有明显提高,从而使玻璃离子的使用范围进一步加大。     

急诊专科护士核心能力评价指标体系的构建

目的通过专家咨询及文献查阅构建出符合我国急诊专科护士核心能力评价的指标体系。方法本次研究主要通过对20名专家进行2轮问卷调查,定量分析各指标的比重。从而判断出评价专科护士核心能力的指标体系。结果专家权威系数为0.90,判断系数为0.86,熟悉程度为0.94;一、二级指标协调系数为0.34和0.73,专家咨询的结果可信。结论文献查阅及专家咨询方法对于急诊专科护士核心能力评价指标体系的构建,临床可信度较高,可以成为较为客观的评价体系。     

杜仲提取物对去卵巢大鼠骨折力和骨压碎力的影响

目的通过制造骨质疏松动物模型,研究去势大鼠骨生物力学指标的变化,为杜仲治疗骨质疏松症提供理论依据。方法将40只雌性SD大鼠随机分为4组,分别为：假手术组、模型组、杜仲提取物小剂量组、杜仲提取物大剂量组。手术摘除卵巢制造骨质疏松病理模型,待其恢复1W后,各给药组每天按剂量灌胃给药60d,取大鼠股骨测定骨折力和骨压碎力。结果杜仲提取物各剂量组骨折力和骨压碎力均高于对照组,差异具有统计学意义（P〈0．05）。结论杜仲提取物可提高去势大鼠骨折力和骨压碎力水平,可有效预防由骨质疏松症所导致的骨折的发生。     

股骨近端防旋髓内钉手术治疗对老年股骨粗隆间骨折患者骨代谢和骨强度的影响

目的 探讨股骨近端防旋髓内钉手术(PFNA)治疗对老年股骨粗隆间骨折患者骨代谢和骨强度的影响.方法 选择2014年1月至2015年8月医院收治的老年股骨粗隆间骨折患者50例为观察组对象,另在医院健康体检处选择50例无骨折病史的正常老年人作为对照组,对观察组患者进行PFNA治疗,测定并比较手术前后观察组患者和对照组正常老年人的骨代谢和骨强度指标.结果 手术前,观察组患者骨代谢指标中前胶原氨基末端前肽Ⅰ型(PINP)、甲状旁腺激素(PTH)、Ⅰ型胶原羧基端肽(CTX)和血清骨钙素(OC)水平均明显高于对照组(均P<0.05),而25(OH)D3明显低于对照组(P<0.05);手术后,观察组患者血清PINP水平[(86.03±27.78)mg/L]较手术前[(53.97±26.13)mg/L]明显升高(P<0.05);PTH水平[(27.67±11.54)ng/L]较手术前[(51.22±17.65)ng/L]明显下降(P<0.05),略高于对照组[(36.85±12.86)ng/L](P>0.05),25(OH)D3、CTX和OC水平与手术前比较无明显变化(均P>0.05).手术前,观察组患者股骨粗隆间区以及股骨颈区骨强度指标中横截面转动贯量(CSMI)、骨密度(BMD)和截面模量z值(Z)均比对照组低(均P<0.05),屈曲比率(BR)明显高于对照组(P<0.05);手术后,观察组患者骨强度指标与手术前相比均稍有下降,但不具有统计学意义(P>0.05).结论 老年股骨粗隆间骨折患者经PFNA治疗后骨代谢增加,骨强度无明显改变,可能由于手术中应力遮挡作用而使髓内钉周围骨有少量丢失,需要加强抗骨质疏松治疗和防护措施以预防骨折.     

High-Entropy Borides under Extreme Environment of Pressures and Temperatures

The high-entropy transition metal borides containing a random distribution of five or more constituent metallic elements offer novel opportunities in designing materials that show crystalline phase stability, high strength, and thermal oxidation resistance under extreme conditions. We present a comprehensive theoretical and experimental investigation of prototypical high-entropy boride (HEB) materials such as (Hf, Mo, Nb, Ta, Ti)B₂ and (Hf, Mo, Nb, Ta, Zr)B₂ under extreme environments of pressures and temperatures. The theoretical tools include modeling elastic properties by special quasi-random structures that predict a bulk modulus of 288 GPa and a shear modulus of 215 GPa at ambient conditions. HEB samples were synthesized under high pressures and high temperatures and studied to 9.5 GPa and 2273 K in a large-volume pressure cell. The thermal equation of state measurement yielded a bulk modulus of 276 GPa, in excellent agreement with theory. The measured compressive yield strength by radial X-ray diffraction technique in a diamond anvil cell was 28 GPa at a pressure of 65 GPa, which is a significant fraction of the shear modulus at high pressures. The high compressive strength and phase stability of this material under high pressures and high temperatures make it an ideal candidate for application as a structural material in nuclear and aerospace fields.     

Assessment of Woodcrete Using Destructive and Non-Destructive Test Methods

Utilizing solid wastes and industrial by-products as a partial replacement for raw materials has become an acceptable practice among researchers and scientists in the civil engineering field. Sawdust and wood shavings are not an exception; they are being used in concrete as a partial or total replacement for some of its constituents. The main goal of this research is to establish a relation between destructive and non-destructive testing for concrete containing wood shavings as a partial replacement of sand (woodcrete). With this type of material existing, thus the need to understand the behavior of such material becomes urgent and evokes the need to ease the process of the assessment and the evaluation of such materials and therefore provide more understanding of its behavior. In addition to the conventional concrete mix, five mixes of woodcrete were made by replacing fine aggregate by volume with wood shavings at different replacement levels varied from 5% to 50%. Cubic samples were tested at the age of 90 days using nondestructive tests (NDT), namely, rebound hammer test and ultrasonic pulse velocity test. Then, the specimens were tested using a conventional compressive test using a universal compression testing machine. Statistical analysis was performed to establish empirical relations between destructive and non-destructive results. The dynamic modulus of elasticity was calculated, and some formulas to estimate the (compressive) strength of woodcrete using NDT results were proposed and tested against experimental results and showed acceptable results.     

Structure-Controlled Porous Cordierite Ceramics with High Solid Content Prepared by Pickering Emulsion Technique Using Sucrose as a Porogen

Porous cordierite ceramics (PCCs) with stable 3D microstructures were prepared by Pickering emulsion technique using sucrose as a porogen. The microstructural and mechanical properties could be adjusted by varying O/S ratios, sintering temperature, and sucrose content. The formation of the spherical structure was due to the broken oil bubbles. The appearance of cordierite and the concurrent consumption of sucrose were responsible for the observation of gradient pore structure. When the O/S ratio was 2, the pore-structure-controlled PCCs with cordierite as the main phase was obtained after sintering at 1300 °C. With the addition of 30 wt.% of sucrose, the obtained PCCs possessed high solid content of 45 vol.%, the porosity of 90.83%, the compressive strength of 6.09 MPa, and the optimized thermal conductivity of 0.4794 W/m.K. Compared with the predecessors’ research results, the as-prepared precursor of PCCs with sucrose content had the lowest initial Zeta potential without adjusting the pH to ensure the stable suspension. Our results showed that the addition of sucrose not only acts as a solvent to increase the solid content, but also acts as a pH modifier to maintain precursor stability, which enables the increase in compressive strength. In this work, via the scenario of “oil droplet” 3D accumulation, the stable and orderly spatial arrangement of the micro-emulsion system was successfully realized to obtain the structure-controlled PCCs by controlling the precursor conditions.     

Evaluation of Tensile Bond Strength between Self-Adhesive Resin Cement and Surface-Pretreated Zirconia

The tensile bond strength between zirconia subjected to different surface-pretreatment methods and methacryloyloxydecyl-dihydrogen-phosphate (MDP)-containing self-adhesive resin cement was evaluated herein. Eighty-eight cylindrical zirconia specimens were randomly divided into the following four groups based on the pretreatment method: (1) no treatment, (2) air abrasion, (3) HNO₃/HF etching, and (4) zirconia-nanoparticle coating. The tensile bond strength of the zirconia–resin-cement complexes was investigated. One-way ANOVA and post hoc tests were performed at a 95% significance level, and the Weibull modulus was calculated. Fracture patterns were visualized by SEM. The surface roughness of the specimens without resin bonding was evaluated by AFM. The tensile bond strength of the specimens decreased as follows: Groups 3 > 4 > 2 > 1 (28.2 ± 6.6, 26.1 ± 5.7, 16.6 ± 3.3, and 13.9 ± 3.0 MPa, respectively). Groups 3 and 4 had significantly higher tensile bond strengths (p < 0.05) and lower fracture probabilities than those of Groups 1 and 2. They also showed both mixed failure and resin-cement cohesive failure, whereas Groups 1 and 2 showed mixed failure exclusively. The zirconia–resin tensile bond was stronger after HNO₃/HF etching or ZrO₂-nanoparticle coating than after air abrasion or no treatment. The estimated surface roughness decreased as follows: Groups 3 > 4 > 2 > 1. The combination of zirconia pretreated with HNO₃/HF etching or ZrO₂-nanoparticle coating and an MDP-containing self-adhesive resin cement can increase the clinical longevity of zirconia restorations by preventing their decementation.     

Substituting Resistance Spot Welding with Flexible Laser Spot Welding to Join Ultra-Thin Foil of Inconel 718 to Thick 410 Steel

This paper investigated various aspects of replacing existing micro-resistance spot welding (micro-RSW) with micro-laser spot welding for joining Inconel 718 thin foils to thick 410 steel stack-up to allow faster, non-contact joining together with flexibility in spot positioning and removal of tip dressing required for RSW electrodes. The joint quality was evaluated based on the mechanical strength, microstructural characteristics and joint strength at elevated temperature as these joints are often used for high-temperature applications. Experimental investigations were performed using micro-RSW and micro-laser spot welding to obtain the 90° peel and lap shear specimens, each comprising four spots. The obtained strength from laser joints was significantly higher than that of micro-RSW joints due to larger weld nugget formation and interface width. The process map for obtaining good quality welds was also identified, and about a 17% reduction in joint strength was obtained when welded specimens were subjected to elevated temperature (i.e., 500 °C) in comparison with room temperature. This reduction was compensated for using the flexibility of laser welding to add two extra spots. The overall performance of the micro-laser spot welds was found to be better than the micro-RSW considering joint strength, flexibility in placing the spots and time to produce the welds.