术前肾穿刺造瘘在输尿管软镜治疗老年肾结石患者中的应用

目的探讨术前肾穿刺造瘘在输尿管软镜联合钬激光治疗老年肾结石患者的临床效果.方法收集2016年2月-2017年8月进行输尿管软镜碎石的老年肾结石患者80例,前瞻性随机对照研究,随机分成观察组与对照组,每组各40例,其中6例退出、3例失访,最终观察组35例,对照组36例.观察组于输尿管软镜钬激光碎石术前先在超声或CT引导下局麻行患侧肾穿刺造瘘,对照组则直接行输尿管软镜钬激光碎石,比较两组结石清除率、术后出血和感染等并发症情况以及住院时间,并检测术前、术毕以及术后24 h的C反应蛋白(CRP)量.结果所有患者手术均成功,观察组未出现大出血、高热等并发症,对照组术后有3例发热.观察组手术时间短于对照组,差异有统计学意义[(45.1±3.1)和(65.5±2.2)min,P<0.05],观察组术后1个月净石率高于对照组[94.3%(33/35)和77.8%(28/36)],术毕及术后24 h炎症指标均明显低于对照组,差异均有统计学意义(P<0.05).结论术前肾穿刺造瘘在输尿管软镜联合钬激光治疗老年患者肾结石中安全有效.

Preface

We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval

Effect of three-step homogenization on microstructure and properties of 7N01 aluminum alloys

The effect of different homogenization treatments on the microstructure and properties of the 7N01 aluminum alloy was investigated using hardness measurements, electrical conductivity measurements, tensile and slow strain rate tests, electron probe microanalysis, optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results revealed that three-step homogenization improved the uniformity of Zr distribution by eliminating segregation of the main alloying elements. During the second homogenization step at 350 °C for 10 h, coarse and strip-like equilibrium η phases formed which assisted the nucleation of Al3Zr dispersoids and reduced the width of the precipitate-free zone of A13Zr dispersoids. As a result, coarse recrystallization was greatly reduced after homogenization at 200 °C, 2 h ＋ 350 °C, 10 h ＋ 470 °C, 12 h, which contributed to improving the overall properties of the 7N01 aluminum alloys.

应用旁置输尿管导管负压吸引的输尿管硬镜钬激光碎石治疗输尿管上段结石

目的探讨应用旁置输尿管导管负压吸引的输尿管硬镜钬激光碎石治疗输尿管上段结石的临床疗效。方法选取2018年1月-2019年3月该科行输尿管硬镜治疗的输尿管上段结石患者83例,随机分为实验组42例(应用旁置输尿管导管负压吸引的输尿管硬镜钬激光碎石)和对照组41例(旁置输尿管导管的输尿管硬镜钬激光碎石)。比较两组碎石时间、结石上移率、术后结石清除率、术后感染发生率和其他并发症(术后输尿管穿孔、黏膜撕脱等)发生率的差异。对于结石上移至肾盂的病例均一期给予输尿管软镜碎石治疗。结果两组一般情况[性别、年龄、结石侧别、体质指数(BMI)]、结石最大长径、结石CT值、结石与肾盂输尿管连接处距离比较,差异均无统计学意义(P>0.05)。实验组术中结石上移病例9例,对照组术中结石上移病例16例。两组碎石时间、结石清除率、其他并发症发生率比较,差异均无统计学意义(P>0.05);两组结石上移率、术后发热率比较,差异均有统计学意义(P<0.05)。结论应用旁置输尿管导管负压吸引的输尿管硬镜钬激光碎石治疗输尿管上段结石具有一定的应用价值,特别适用于没有输尿管软镜及封堵器、套石篮等手术器械的基层医院。

Quenching sensitivity and heterogeneous precipitation behavior of AA7136 alloy

The quenching sensitivity of AA7136 alloy was investigated by time−temperature−property(TTP)diagrams,and the heterogeneous precipitation behavior during isothermal holding was investigated using scanning electron microscopy,scanning transmission electron microscopy and high resolution transmission electron microscopy.Based on 99.5%TTP diagram,the nose temperature is determined to be about 346℃ with the transformation time of about 0.245 s.The precipitation ofη(MgZn_(2)),T(Al_(2)Zn_(3)Mg_(3)),S(Al_(2)CuMg)or Cu−Zn-rich Y phases can be found depending on isothermal holding temperature and time,and it is described in a time−temperature−precipitation diagram.The size and area fraction of isothermal holding induced phase particles increase,which results in the decrease of hardness of samples after aging.The quantitative contribution to loss of hardness by grain boundaries/subgrain boundaries and dispersoids in the matrix is discussed based on the amount of heterogeneous precipitation related to them.

Microstructure,mechanical properties and stress corrosion behavior of friction stir welded joint of Al-Mg-Si alloy extrusion

Microstructure,mechanical properties and stress corrosion behavior of friction stir welded(FSWed) AlMg-Si alloy were investigated.The average grain sizes of shoulder-affected zone(SAZ),nugget zone(NZ),heat-affected zone(HAZ) and base material(BM) are 6.03,4.80,168.30 and 127.24 μm,respectively.The thermo-mechanically affected zone(TMAZ),which is generated on the edge position between HAZ and weld nugget zone,has a narrow width of 400 μm.The ultimate tensile strength(UTS) of FSWed joint is 232.20 MPa,about 91.04% with respect to that of base material of 255.06 MPa,and the joint fracture occurs at HAZ on advancing side(AS).The FSWed joint is more susceptive to stress corrosion cracking(SCC) than base material,and the SCC susceptibility increases with the rise in temperature.The residual UTS of FSWed joints in constant loaded tests at the load levels of90,105 and 120 MPa is 89.97%,67.50% and 54.75% of the UST of FSWed joint in air,respectively.The increase of the load in constant loaded tests and four-point beambent tests accelerates the SCC of FSWed joints.

Synthetic Data Generation and Shuffled Multi-Round Training Based Offline Handwritten Mathematical Expression Recognition

Offline handwritten mathematical expression recognition is a challenging optical character recognition(OCR)task due to various ambiguities of handwritten symbols and complicated two-dimensional structures.Recent work in this area usually constructs deeper and deeper neural networks trained with end-to-end approaches to improve the performance.However,the higher the complexity of the network,the more the computing resources and time required.To improve the performance without more computing requirements,we concentrate on the training data and the training strategy in this paper.We propose a data augmentation method which can generate synthetic samples with new LaTeX notations by only using the official training data of CROHME.Moreover,we propose a novel training strategy called Shuffled Multi-Round Training(SMRT)to regularize the model.With the generated data and the shuffled multi-round training strategy,we achieve the state-of-the-art result in expression accuracy,i.e.,59.74%and 61.57%on CROHME 2014 and 2016,respectively,by using attention-based encoder-decoder models for offline handwritten mathematical expression recognition.