Bismuth Sodium Titanate Based Materials for Piezoelectric Actuators

The ban of lead in many electronic products and the expectation that, sooner or later, this ban will include the currently exempt piezoelectric ceramics based on Lead-Zirconate-Titanate has motivated many research groups to look for lead-free substitutes. After a short overview on different classes of lead-free piezoelectric ceramics with large strain, this review will focus on Bismuth-Sodium-Titanate and its solid solutions. These compounds exhibit extraordinarily high strain, due to a field induced phase transition, which makes them attractive for actuator applications. The structural features of these materials and the origin of the field-induced strain will be revised. Technologies for texturing, which increases the useable strain, will be introduced. Finally, the features that are relevant for the application of these materials in a multilayer design will be summarized.     

Dexamethasone as an adjuvant for peripheral nerve blockade: a randomised,triple-blinded crossover study in volunteers

Background

The efficacy of dexamethasone in extending the duration of local anaesthetic block is uncertain. In a randomised controlled triple blind crossover study in volunteers, we tested the hypothesis that neither i.v. nor perineurally administered dexamethasone prolongs the sensory block achieved with ropivacaine.

帕拉米韦注射液治疗儿童流感的临床疗效分析

目的探讨儿童流感应用帕拉米韦注射液治疗的临床疗效以及用药安全性。方法随机选定在2016年1月-2019年1月期间佛山市高明区人民医院儿科住院治疗并确诊流感A或B型患儿200例,通过随机数字法将其分为治疗组和对照组。治疗组100例用帕拉米韦注射液治疗,对照组100例用国产磷酸奥司他韦颗粒治疗,评价两组患儿治疗前后症状评分、治疗效果、治疗指标以及不良反应发生情况。结果两组患儿治疗前流感样症状评分无统计学意义(P>0.05),两组患儿治疗后较治疗前流感样症状评分均下降,差异有统计学意义(P<0.05);治疗组治疗后流感样症状评分略小于对照组,但是无统计学意义(P>0.05);治疗组治疗总有效率高于对照组,治疗组患儿发热症状缓解、全部症状缓解以及住院时间均小于对照组,存在统计学意义(P<0.05)。治疗组与对照组不良反应发生率较低,且无统计学意义(P>0.05)。结论帕拉米韦注射液可用于儿童流感治疗,不仅能够保证临床疗效,而且可加快症状缓解,同时存在较高用药安全性。     

Revisiting the Hydrogen Storage Behavior of the Na-O-H System

Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS) experiments of NaH-NaOH composites reveal two principal features: Firstly, an H₂ desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH) and hydridic hydrogen (in NaH) important in the dehydrogenation mechanism, but that also an intra-phase H^δ+… H^δ– interaction may be a crucial step in the desorption process.     

血抗栓汤内服联合西医治疗急性脑梗死疗效分析

目的观察活血抗栓汤联合奥扎格雷钠治疗急性脑梗死疗效。方法将80患者按抽签法分为观察组和对照组各40例。对照组奥扎格雷钠氯化钠注射液,500 mL/次,2次/d,静滴,治疗2周。治疗组在对照组基础上加用活血抗栓汤,水煎200 mL,1剂/d,2次/d,治疗2周。观测临床症状、神经功能、日常生活能力、凝血功能。结果治疗后,观察组红细胞聚集指数、血细胞容积、纤维蛋白原、全血高切黏度、血浆比黏度改善程度高于对照组(P<0.05)。治疗前,两组ADL评分、NIHSS评分比较,无显著差异(P>0.05),治疗后,观察组NIHSS评分低于对照组,ADL评分高于对照组(P<0.05)。结论血抗栓汤内服联合西医治疗急性脑梗死,可改善凝血功,值得推广。     

A facile synthesis of [14C]pyrithiobac‐sodium

Condensation of thiourea 1 with diethyl malonate 2 in the presence of sodium methoxide furnished 4,6‐dihydroxy‐2‐mercaptopyrimidine 3 . Compound 3 on methylation with diazomethane followed by oxidation with H₅IO₆/CrO₃ in ethyl acetate gave 4,6‐dimethoxy‐2‐methylsulphonylpyrimidine 5 . Compound 5 on condensation with 2‐mercapto‐6‐chlorobenzoic acid in the presence of a phase transfer catalyst, tetrabutylammonium bromide and sodium carbonate gave the title compound – pyrithiobac‐sodium 6 with an overall yield of > 35% starting from thiourea. Following the above standardized procedure, using [¹⁴C]‐thiourea in lieu of thiourea, ¹⁴C labelled product 6 , was synthesized with an overall radiochemical yield > 30% (with respect to [¹⁴C]‐thiourea) for further evaluations of environmental fate of 6 , in soils and plants. Copyright © 2006 John Wiley & Sons, Ltd.     

携载rhBMP-2微球的新型可注射自凝固复合人工骨的制备及特性研究

[目的]制备一种具有良好降解性和成骨活性、可注射的自凝固新型骨修复材料。[方法]制备携载rhBMP-2的聚乳酸与聚乙醇酸共聚物（PLGA）微球，并将其与rhBMP-2／磷酸钙骨水泥（CPC）复合，制备出rhBMP-2／PLGA微球／CPC复合人工骨。探讨了材料的特性，包括形貌、固化时间、抗压强度及反映材料体外降解速度的指标一体外降解液Ca、P浓度变化，测定复合材料rhBMP乏的释药速度及体外诱导MSCs细胞成骨分化的能力。[结果]与单纯CPC-rhBMP-2相比，复合材料的固化时间少量增加，抗压强度下降明显。体外降解速度及体外释药明显提高，释放的rhBMP-2具有骨诱导活性。[结论]rhBMP-2／PLGA微球／磷酸钙骨水泥新型复合人工骨是具有良好应用前景的骨修复材料。     

Ligustrazine inhibits high voltage-gated Ca~(2+) and TTX-resistant Na~+ channels of primary sensory neuron and thermal nociception in the rat:a study on peripheral mechanism

Objective Ligustrazine, also named as tetramethylpyrazine, is a compound purified from Ligusticum chuanxiong hort and has ever been testified to be a calcium antagonist. The present investigation was to determine the antinoci-ceptive effect of ligustrazine and, if any, the peripheral ionic mechanism involved. Methods Paw withdrawal Latency ( PWL) to noxious heating was measured in vivo and whole-cell patch recording was performed on small dorsal root ganglion (DRG) neurons. Results Intraplantar injection of ligustrazine (0.5 mg in 25μl) significantly prolonged the withdrawal latency of ipsilateral hindpaw to noxious heating in the rat. Ligustrazine not only reversibly inhibited high-voltage gated calcium current of dorsal root ganglion (DRG) neuron in dose-dependent manner with IC50 of 1.89 mmol/L, but also decreased tetrodotoxin (TTX) -resistant sodium current in relatively selective and dose-dependent manner with IC50 of 2.49 mmol/L. Conclusion The results suggested that ligustrazine could elevate the threshold of thermal nociception through inhibiting the high-voltage gated calcium current and TTX-resistant sodium current of DRG neuron in the rat.