Effect of Bi,Sb, and Ti on Microstructure and Mechanical Properties of SAC105 Alloys

The Sn-Ag-Cu (SAC) solder alloys with a low Ag (Ag < 3 wt.%) content have attracted great attention owing to their low cost, increased ability in bulk compliance, and plastic energy dissipation. However, some of their mechanical properties are generally lower than the SAC alloys with a higher Ag content. Adding alloying elements is an effective approach for improving the mechanical properties of the SAC alloys. In this study, the effect of Bi, Sb, and Ti on Sn-1 wt.%Ag-0.5 wt.%Cu (SAC105) solder alloys was investigated. The SAC solders with four compositions: SAC105-1 wt.%Bi, SAC105-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb-0.4 wt.%Ti were prepared. The microstructure and phase compositions were characterized using electron scanning microscopy, and X-ray diffraction. The thermal properties and wettability were also examined. Uniaxial tensile tests and nano-indentation tests were conducted to evaluate the mechanical properties. The results show that adding Bi or Sb could increase the strength of SAC105 alloys mainly due to the solid solution strengthening effect. The creep resistance of SAC105 alloys was also improved with the additions of Bi and Sb. The co-additions of Bi and Sb into SAC105 alloys exhibit an enhanced creep resistance than that calculated by the theoretical calculation. The further addition of Ti into SAC105-1Bi-1Sb alloys demonstrated a much-improved creep resistance, which could be attributed to the synergistic effects of both solid solution strengthening and the precipitation hardening effects.     

18β-glycyrrhetinic acid inhibits migration and invasion of human gastric cancer cells via the ROS/PKC-α/ERK pathway

Journal of Natural Medicines - 18β-glycyrrhetinic acid (18β-GA) is a bioactive component of licorice root which exerts pharmacological activities including anti-inflammatory, antiviral,...     

Time-Dependent Seismic Performance of Coastal Bridges Reinforced with Hybrid FRP and Steel Bars

To increase the durability and seismic resilience of coastal bridges, a hybrid reinforced concrete (HRC) bridge that incorporates both glass fiber-reinforced polymer (GFRP) bars and steel bars is proposed. The time-dependent seismic performance of the HRC bridge is comprehensively investigated at three levels, namely the material, bridge column and bridge structure levels. First, the decrease of tensile strength of GFRP bars over time is analyzed based on the Arrhenius theory, and corrosion initiation time and performance deterioration of steel bars are determined by Fick’s second law and an empirical formula. Second, an efficient finite element modeling method for aging HRC bridge columns is proposed. Simulation of the compression/tension behavior and the fracture failure of the GFRP bar is described. Hysteretic analysis is further conducted to investigate the time-dependent energy dissipation, ductility, residual displacement, bearing capacity and post-yield stiffness ratio. Meanwhile, comparisons of HRC bridge columns to reinforced concrete (RC) references are provided. Third, the seismic demand and damage evolution of deteriorated HRC bridge structures are investigated through dynamic time-history analysis. The results indicate that the corrosion-resistant GFRP bars contribute to improving the bearing capacity and to reducing the residual displacement of the HRC bridge. With an increase in service time, the seismic damage to the bridge column, abutment and expansion bearing increases, but the damage to fixed bearing decreases. Research results presented herein show that the HRC bridge is a promising alternative structure scheme in the marine environment.     

PRK术后角膜上皮下雾状混浊的相关因素分析

为探讨准分子激光角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）后角膜上皮下雾状混浊（ｈａｚｅ）的原因及影响因素，对ＰＲＫ后６个月时屈光度在－１．００～－１８．５０Ｄ的３１６例（６１５只眼）近视眼的ｈａｚｅ相关因素进行观察和比较。结果：ＰＲＫ后６个月时ｈａｚｅ发生率为４４．７％，１级或以上ｈａｚｅ为１３．３％。ｈａｚｅ的发生率及密度随屈光度增高而增加（Ｐ＜０．０００１），也随切削深度的增加而增加（Ｐ＜０．０００１），术前非接触眼压超过１８ｍｍＨｇ者，ｈａｚｅ的发生率和密度增加（Ｐ＜０．００５），男性较易发生ｈａｚｅ（Ｐ＝０．０００１），与年龄呈负相关（Ｐ＜０．０５）。而角膜厚度、术前戴用接触镜及散光对ｈａｚｅ的影响不显著。结论：高度近视（＞－６．０Ｄ）和过深的切削（＞８０μｍ）是引起ｈａｚｅ的主要原因。术前眼压偏高、年龄偏低对ｈａｚｅ也有明显影响。对ＰＲＫ治疗高度近视应持审     

IPSS-V/S在TUVP术后下尿路症状评估的临床价值

目的：探讨国际前列腺症状评分的排尿期/储尿期评分比值（international prostatic symptom score-voiding/storage sub－score ratio,IPSS-V/S）在经尿道前列腺汽化电切术（transurethral electrovaporization prostatectomy,TUVP）术后下尿路症状（lower urinary tract symptoms,LUTS）再评估的临床价值。方法：回顾性分析了2015年1月至2016年12月期间234例接受TUVP的良性前列腺增生（benign prostatic hyperplasia,BPH）患者的国际前列腺症状评分（international prostatic symptom score,IPSS）等临床资料。按照IPSS-V/S比值将患者分为A组（IPSS-V/S≤1,80例）和B组（IPSS-V/S>1,154例）。术后6个月再次评估IPSS,储尿期症状评分（international prostatic symptom score-storage,IPSS-S）,排尿期症状评分（international prostatic symptom score-voiding,IPSS-V）和生活质量评分（quality of life,QOL）。结果：234例患者术后6个月IPSS和QOL较术前明显降低,差异有统计学意义（t=33.0,P=0.000;t=34.3,P=0.000）。术后6个月B组患者IPSS改善程度明显优于A组[（12.36±3.67）分 vs. （8.20±3.21）分]（t=8.96,P=0.000）。其中A组术后6个月IPSS-S明显高于B组[（9.61±2.88）分 vs. （5.55±2.63）分]（t=10.8,P=0.000）;而2组患者术后6个月时IPSS-V对比无统计学差异（t=1.56,P=0.120）。虽然A组术后6个月的QOL明显改善[（3.59±0.91）分 vs.（5.19±0.55）分]（t=14.8,P=0.000）,但是基本满意及以上者仅占13.75%,明显低于B组的70.78%。A组术后6个月IPSS-S各症状评分均有一定改善,改善程度从高到低依次为尿急评分、尿频评分和夜尿评分,其中夜尿评分改善率最低,仅为36.3%（29/80）,是A组患者IPSS及QOL改善较小的重要原因。结论：相比IPSS,IPSS-V/S更能准确反映TUVP术后疗效,LUTS排尿期症状改善明显优于储尿期症状。对于以夜尿症为主的BPH/LUTS患者,TUVP对患者QOL改善有限,需要引起临床医师重视。     

Autophagic and apoptotic cell death in amniotic epithelial cells

The aim of this paper is to determine if autophagic cell death is associated with apoptosis and whether it participates in the process of term amniotic rupture. Forty pieces of fresh term amnions, including twenty from a position near the margin of the placentas and twenty from the margin of the naturally ruptured part of the placentas in term gestation were collected, respectively. The amnions were examined by scanning electron microscopy (SEM) and amniotic epithelial (AE) cells were examined by transmission electron microscopy (TEM). Autophagic and apoptotic cell death (PCD) were assayed by laser scanning confocal microscopy (LSCM) or flow cytometry using monodansylcadaverin (MDC) and propidium iodide (PI) stain. BCL(2) and BAX were examined by immunoblotting. Under SEM the amniotic epithelia appeared normal in the position near the placenta. They had an atrophied appearance in the margin of their natural broken parts. In the AE cells PCD was divided into three subtypes by TEM: autophagic cell death with positive stains of MDC and PI; apoptotic cell death; and the mixed type. Quantitative detection showed that there were more death cells, including autophagic and apoptotic, in the AE cells near the ruptured parts than near the placentas. An increased expression of BAX and a decreased expression of BCL(2) protein in the AE cells near the broken margin were observed. Apoptotic and autophagic cell death by the intrinsic pathway are the basic event in the AE cell and they are involved in the cause of membrane rupture of the human amnion in term gestation.