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.     

~(27)AINMR对碱式氯化铝的研究

实验室制得的碱式氯化铝,用~(27)Al NMR进行分析,发现在众多聚合体中存在[AlO_4Al_(12)(OH)_(24)(H_2O)_(12)]~(7+)离子,其化学位移相对于六水合铝离子[Al(H_2O)_6]~(3+)的零位移为δ=63ppm,试铁灵定时比色法对其存在进行了验证。研究了反应条件如酸浓度、铝酸当量比和陈化时间对产物组成及质量的影响,得出最佳条件为盐酸浓度16%,铝酸当量比为1:0.5,陈化时间为50h左右。     

Immunotherapy of tree pollen allergy with a modified alginate conjugated birch pollen extract compared to an aluminium adsorbed extract

The safety and efficacy of two birch pollen extracts, one chemically conjugated to alginate (Anjuvac) the other adsorbed to aluminium hydroxide (Alutard), were investigated in an open multicentre comparative study of 63 birch pollen allergic patients. Both extracts decreased the nasal symptoms during the birch pollen season. The changes in specific IgE and IgG were much the same in both treatment groups. The adverse reactions recorded were mild in both groups, but more frequent in the Anjuvac group, probably because of a more aggressive dose schedule though there were twice as many asthmatics in the Anjuvac group. The two investigated allergen extracts were useful alternatives for immunotherapy.     

添加剂对钛酸铝低膨胀陶瓷热稳定性影响

通过计算晶格常数和热分解率,研究了添加剂莫来石和氧化铁对钛酸铝陶瓷热分解影响的机理,实验结果表明,莫来石通过挤压作用,而氧化铁通过形成固溶体来抑制钛酸铝陶瓷热分解。莫来石和氧化铁的混合添加剂比单用莫来石抑制效果更好。     

猪肝样品中铝含量的测定

目的介绍用石墨炉原子吸收分光光度法测定猪肝中铝含量的方法.方法样品在聚四氟消解器中消解.采用标准加入法在石墨炉原子吸收光度计上测定铝的含量.结果分析了8份猪肝样品,平均铝含量(4.10±0.17)μg/g,变异系数为4.3%.铝测定的回收率为96.3%±3.28%.用人发标样测定了方法的准确度为(13.1±1.8)μg/g,标准为(13.3±2.3)μg/g.结论这是一种准确、精密、可靠的分析方法.本方法也适用于其他生物组织样品中铝含量的测定.     

纳络酮用于改善小鼠学习记忆障碍的研究

采用口服氯化铝建立小鼠学习记忆障碍模型,应用跳台法观察了纳络酮对铝(Al)中毒所致小鼠学习记忆障碍的改善作用,用火焰原子吸收分光光度法测定血锌(Zn)、铜(Cu)、锰(Mn)等含量.结果显示,氯化铝可导致小鼠学习记忆障碍,且有降低血Zn、Cu含量的作用(P<0.05);纳络酮治疗有改善Al中毒小鼠学习记忆障碍的作用,同时也增加了血Zn、Cu的含量.     

Low-dose (5 mg/kg) desferrioxamine treatment in acutely aluminium-intoxicated haemodialysis patients using two drug administration schedules

BACKGROUND: According to the recommendations proposed at The Consensus Conferenceon Diagnosis and Treatment of Aluminium Overload in End-StageRenal Failure Patients, Paris, 1992 low-dose desferrioxamine(DFO) treatment was applied for the first time in 41 acutelyaluminium-intoxicated patients. METHODS AND RESULTS: DFO-related neurological/ophthalmological side-effects wereobserved in nine of 11 patients with a post-DFO serum aluminiumlevel >300 µg/litre and in two patients of 30 belowthis level after a single administration of a 5-mg/kg dose ofthe chelator in the conventional way (i.e. the last hour ofa dialysis session). They were no longer observed after introducingan alternative DFO administration schedule (i.e. administrationof the chelator 5 h prior to the start of a haemodialysis session;group I: n=14). A significant decrease in the serum aluminiumlevels as well as in the post-DFO serum aluminium increment(sAl) was observed during the first 6 months' course of low-doseDFO treatment in group I as well as group II (which consistedof patients receiving DFO in the conventional way; n=27). Low-doseDFO treatment was accompanied by a significant increase in themean ±SD serum iPTH levels (group I: 174±245 upto 286±285 ng/litre; group II: 206±272 up to 409±424ng/litre; P<0.005) and the mean corpuscular volume (groupI: 80±6.4 up to 85±3.7 fL, P<0.005; group II:76±5.0 up to 87±4.3 fL, P<0.0001). Serum ferritinlevels significantly decreased in both groups. No further side-effectswere observed during the DFO course. Patients in which DFO treatmentcould be stopped (i.e. subjects in which both serum aluminiumand sAl were below 50 µg/litre at two successive occasions)before the end of the 6-months' treatment course had a significantlygreate residual diuresis (700±682 ml/min vs 84±109ml/24 h). Also, residual diuresis was found to protect againstaluminium intoxication as reflected by the values noted in groupI versus those in group II. CONCLUSIONS: The 5-mg/kg DFO treatment provides a safe and adequate therapyfor aluminium overload. In severely aluminium-intoxicated patientspresenting post-DFO serum aluminium levels above 300 µg/litreDFO should be given once weekly 5 h prior to high-extractiondialysis ensuring (i) maximal chelation of aluminium (ii) limitedexposure to circulating aluminoxamine levels, and (iii) adequateremoval of the latter compound. Finally, the necessity for abetter communication between the local water distribution companiesand the dialysis centres is a major lesson that can be drawnfrom this dramatic intoxication.     

铝对大鼠海马ERK蛋白及mRNA表达影响

目的研究慢性铝中毒对大鼠海马细胞外信号调节蛋白激酶（ERK）蛋白及mRNA表达水平的变化，探讨铝中毒对学习记忆机制的影响。方法选择断乳后Wistar大鼠，用不同浓度AlCl3的水饲养3个月。测量大鼠海马长时程增强（LTP），用改良的Takai法测定丝裂原活化蛋白激酶（MAPK）活性的变化。蛋白印迹（Western blotting）方法检测ERK1／2的蛋白含量，RT-PCR方法检测ERK2的mRNA表达。结果（1）各染铝组MAPK活性降低且与对照组比较差异有统计学意义（P〈0．05）；（2）ERK1／2蛋白表达的比较：①ERK2在大鼠海马中的蛋白含量高于ERK1；②染铝组ERK1／2非磷酸水平与对照组比较均有所下降（P〈0．05），但染铝组之间差异无统计学意义（P〉0．05）；③染铝组ERK1／2磷酸化水平与对照组的比较均有下降（P〈0．05），染铝组之间的差异有统计学意义（P〈0．05）。（3）染铝组ERK2的mRNA表达与对照组比较明显降低，但染铝组之间差异无统计学意义（P〉0．05）。结论慢性铝中毒不仅影响大鼠海马中ERK2的mRNA表达水平，同时也影响ERK1／2的蛋白表达水平的降低，造成有丝分裂原活化蛋白激酶（MAPK）活性的下降，损害LTP的形成，从而影响学习记忆功能下降。     

Immune responses of a meningococcal A + W outer membrane vesicle (OMV) vaccine with and without aluminium hydroxide adjuvant in two different mouse strains

Meningococci (Neisseria meningiditis) of serogroups A and W have caused large epidemics of meningitis in sub‐Saharan Africa for decades, and affordable and multivalent vaccines, effective in all age groups, are needed. A bivalent serogroup A and W (A + W) meningococcal vaccine candidate consisting of deoxycholate‐extracted outer membrane vesicles (OMV) from representative African disease isolates was previously found to be highly immunogenic in outbred mice when formulated with the adjuvant aluminium hydroxide (AH). OMV has been shown to have inherent adjuvant properties. In order to study the importance of AH and genetical differences between mice strains on immune responses, we compared the immunogenicity of the A + W OMV vaccine when formulated with or without AH in inbred C57BL/6J and BALB/cJ mice (Th1 and Th2 dominant strains, respectively). The immunogenicity of the vaccine was found to be comparable in the two mice strains despite their different immune profiles. Adsorption to AH increased anti‐OMV IgG levels and serum bactericidal activity (SBA). The immune responses were increased by each dose for the adsorbed vaccine, but the third dose did not significantly improve the immunogenicity further. Thus, a vaccine formulation with the A and W OMV will likely benefit from including AH as adjuvant.