High Pressure Pneumatic Forming of Ti-3Al-2.5V Titanium Tubes in a Square Cross-Sectional Die

A new high strain rate forming process for titanium alloys is presented and named High Pressure Pneumatic Forming (HPPF), which might be applicable to form certain tubular components with irregular cross sections with high efficiency, both with respect to energy cost and time consumption. HPPF experiments were performed on Ti-3Al-2.5V titanium alloy tubes using a square cross-sectional die with a small corner radius. The effects of forming of pressure and temperature on the corner filling were investigated and the thickness distributions after the HPPF processes at various pressure levels are discussed. At the same time, the stress state, strain and strain rate distribution during the HPPF process were numerically analyzed by the finite element method. Microstructure evolution of the formed tubes was also analyzed by using electron back scattering diffraction (EBSD). Because of different stress states, the strain and strain rate are very different at different areas of the tube during the corner filling process, and consequently the microstructure of the formed component is affected to some degree. The results verified that HPPF is a potential technology to form titanium tubular components with complicated geometrical features with high efficiency.     

A local angle compensation method based on kinematics constraints for non-invasive vascular axial strain computations on human carotid arteries

Non invasive vascular elastography (NIVE) was developed to highlight atherosclerotic plaque constituents. However, NIVE motion estimates are affected by artifacts, such as an underestimation of deformations due to projected movement angles with respect to the ultrasound beam, movements of the operator or of the patient during image acquisition. The main objective of this work was to propose a local angle compensation method within small measurement windows for the axial strain based on kinematics constraints, and to introduce a filtering process on the strain time-varying curve to reduce as much as possible the impact of motion artifacts. With such preprocessing, we successfully quantified the strain behavior of near and far walls in longitudinal images of internal carotid arteries without (n = 30) and with (n = 21) significant atherosclerotic disease (greater than 50% stenosis). Maximum strain rates of 4.49% s⁻¹ for the healthy group and of 2.29% s⁻¹ for the atherosclerotic group were calculated on the far wall of internal carotid arteries; significant differences were found between these values (p = 0.001). The minimum strain rates, also on the far wall of internal carotid arteries, of −3.68% s⁻¹ for the healthy group and of −1.89% s⁻¹ for the atherosclerotic group were significantly different as well (p = 8 ×10⁻⁴). The mean systolic, diastolic and cumulated axial strains could also distinguish the two groups after normalization by the pressure gradient between acquired images. To conclude, the proposed techniques allowed to differentiate healthy and atherosclerotic carotid arteries and may help to diagnose vulnerable plaques.     

不同剂量螺内酯对肾功能正常收缩性心力衰竭患者的疗效和安全性

目的探讨不同剂量螺内酯对肾功能正常的收缩性心力衰竭患者的疗效和安全性。方法入选2011年12月—-2012年12月肾功能正常的收缩性心力衰竭患者148例,在常规治疗的基础上随机分为每天螺内醇20mg组72例、60 mg组76例。所有患者在入选前及用药12个月后检测B型脑钠肽(BNP)水平,同时行超声心动图检查评估左室舒张末期容积指数(LVEDVI)、左室收缩末期容积指数(LVESVI)、左室质量指数(LVMI)和左室射血分数(LNEF)的变化。并监测血钾、肾功能及不良事件发生情况。结果治疗12个月时,2组LVEDVI、LVESVI、LVMI、LVEF和BNP均较治疗前有明显改善(P<0.05),60 mg组较20 mg组改善更明显,差异均有统计学意义(P<0.05)。60 mg组较20 mg组高钾血症(血钾≥5.5 mmol/L)的发生率升高不明显(7.9%vs.2.8%),无统计学差异(P>0.05)。2组中均末发生严重高钾血症(血钾≥6.0 mmol/L)。20 mg组较60 mg组低钾血症的发生率明显增加(2.6%vs.11.1%),且差异有统计学意义(P<0.05)。60 mg组较20 mg组乳房发育及乳房疼痛的发生率明显升高(13.2%vs.2.8%),且差异有统计学意义(P<0.05)。2组各有2例血肌酐增长较上次检验值>50%的患者,差异无统计学意义(P>0.05),均无血肌酐增长>180μmol/L者。结论肾功能正常的收缩性心力衰竭患者在常规治疗的基础上应用每日60 mg螺内酯可进一步改善患者的心室重构,降低BNP水平,减少低钾血症的发生,在密切监测下应用是安全的。     

慢性心力衰竭患者系统化干预对心功能状况和再住院率的影响

目的 探讨系统化院外干预对慢性心力衰竭（CHF）患者心功能及再住院率的影响.方法 入选2008年7月至2010年7月中国医科大学北京顺义医院心内科住院CHF患者160例,按随机数字表法分为干预组79例,对照组81例.干预组患者根据心功能的变化和临床症状进行系统化干预,包括规范治疗方案,指导患者正确使用血管紧张素转换酶抑制剂和β-受体阻滞剂,并滴定其靶剂量等措施.对照组不做系统化干预,了解记录自用药情况和其他相关内容.6个月和12个月时分别对两组患者采用6分钟步行试验及超声心动图检查对患者的心功能状况进行评价,使用再住院率对患者临床症状改善进行评价.结果 6、12个月时干预组6分钟步行距离[（345.27±123.95）、（368.94±121.62） m]明显高于对照组[（282.53±94.63）、（260.07±86.13） m],差异有统计学意义（F组间=38.01,P＜0.01;F组内=19.62,P＜0.01;F交互=48.36,P＜0.01）.干预组的左心室射血分数[6个月（43.48±8.42）％,12个月（41.21±6.23）％]明显高于对照组[（37.70±7.13）％、（37.15±6.83）％]（P＜0.01）.6个月时干预组再住院率有下降趋势,12个月时干预组再住院次数（26次）明显低于对照组（36次）,差异有统计学意义（P =0.024）.结论 CHF患者采用系统化干预可以改善其心功能并降低再住院率.     

丙肝抗体联合丙肝核心抗原在丙型肝炎诊断中的作用

目的 分析丙肝抗体与丙肝核心抗原联合诊断丙型肝炎的临床效果.方法 选取180例2017年1月—2018年6月在本单位采集的单试剂丙型肝炎阳性的献血者血样,对血清标本的丙肝抗体、丙肝核心抗原进行检测,分析不同方法 诊断丙型肝炎的效果.结果 以重组免疫印迹试验结果 为诊断标准,丙肝抗体诊断丙型肝炎的灵敏度、特异度、阳性预测...     

基于自主神经功能的不同选穴原则对无先兆性偏头痛患者针刺干预的随机对照研究

目的:基于自主神经功能探讨不同选穴原则干预无先兆性偏头痛患者的治疗效果.方法:2016年11月至2018年6月收集浙江中医药大学附属第三医院针灸科符合纳入标准的偏头痛患者84例,随机分为自主神经组41例(脱失1例)和常规治疗组40例(脱失2例),治疗频率为3次/周,均治疗2周,8周后回访.缓解期检测心率变异性特征,包括...