Block Copolymers of Methyl Vinyl Ether and Isobutyl Vinyl Ether With Thermo‐Adjustable Amphiphilic Properties

The thermo‐adjustable hydrophilic/hydrophobic properties of AB, ABA and BAB block copolymers in which A is poly(methyl vinyl ether) (PMVE) and B is poly(isobutyl vinyl ether) (PIBVE) have been investigated. The block copolymers were prepared by “living” cationic polymerization using sequential addition of monomers. The polymerizations were carried out with the system acetal/trimethylsilyl iodide as initiator and ZnI₂ as activator. The initiating system based on diethoxyethane leads to AB block copolymers whereas the initiating system based on tetramethoxypropane leads to ABA or BAB triblock copolymers. Well‐defined block copolymers of different composition with controlled molecular weights up to approx. 10 000 have been prepared. When IBVE is added to living PMVE, PIBVE‐blocks form only in the presence of an additional amount of ZnI₂, which is attributed to the fact that part of the ZnI₂ is inactive because of complex formation with PMVE. At room temperature, the combination of hydrophilic (PMVE) and hydrophobic (PIBVE) segments provides the copolymers with surfactant properties. Above the lower critical solution temperature (LCST) of PMVE, situated around 36 °C, the PMVE‐blocks become hydrophobic and the amphiphilic nature of the block copolymers is lost. The corresponding changes in hydrophilic/hydrophobic balance have been evaluated by investigation of the emulsifying properties of the block copolymers for water/decane mixtures as a function of the temperature. Below the LCST, the block copolymers have emulsifying properties similar to or better than those of the commercial PEO‐PPO block copolymers (Pluronic®). Either oil‐in‐water or water‐in‐oil emulsions can be obtained, depending on the polymer architecture and the water/decane volume ratio. The emulsifying properties are strongly reduced or completely lost above 40 °C. Emulsions obtained with a PMVE₃₆‐b‐PIBVE₅₄ block copolymer for a water/decane (v/v) ratio of 85/15 remained stable for more than six months.

50/50 and a 85/15 water/decane w/o emulsion (15 g/l) with the PMVE₃₆‐b‐PIBVE₅₄ block copolymer at 20 °C.     

温敏性高分子材料对药物释放的研究

 目的合成一系列温度敏感性(温敏性)凝胶，测定其低临界溶液温度(相变温度)。筛选出具有与人体体温相近的相变温度的凝胶，并使其可以作为药物的载体。方法采用自由基水溶液聚合的方法合成共聚物，然后用聚合物承载药物并用高效液相色谱法测其不同温度下药物的释放情况。结果温敏性凝胶可以作为自控式或缓释药用辅料，但如果相变温度低于人体体温，则无实际应用意义。采用共聚合的方法，确可提高凝胶的相变温度。不同条件下合成的共聚物有着不同的相变温度，药物释放情况也不同。结论调整不同组成比例及交联剂的浓度，可使此类凝胶作为自控式或缓释药用辅料成为可能。     

化疗引起的神经痛治疗靶点温度选择性TRP通道的研究进展

作为钙离子渗透性的瞬时受体电位(TRP),5种通道(TRPV1~4和TRPM2)被不同的高温激活,两种通道(TRPV1和TRPV8)被低温激活。越来越多的证据表明,TRPA1和TRPM8拮抗剂可预防顺铂、奥沙利铂和紫杉醇诱导的线粒体氧化应激、炎症、冷痛和痛觉过敏。TRPV1在顺铂引起的感觉神经元热痛觉和机械异常中有应答。TRPA1、TRPM8和TRPV2蛋白表达水平主要通过这些治疗方法在背根(DRG)和三叉神经节中增加。主要总结了5种温度调节TRP通道(TRPA1、TRPM8、TRPV1、TRPV2和TRPV4)。     

射频热凝术治疗原发性三叉神经痛的临床疗效观察

目的探讨射频热凝术治疗原发性三叉神经痛的临床疗效。方法 2007年11月至2009年11月我院神经内科收治的原发性三叉神经痛患者54例,采用Hartel前入路穿刺法将射频热凝温度控制在60℃～80℃,治疗4min～8min。结果 54例中,疗效优48例,良3例,好转2例,无效1例。优良率94.44%。再次射频治疗2例。结论射频热凝术治疗原发性三叉神经痛是一种有效、安全的治疗方法。     

Second‐look endoscopy with thermal coagulation or injections for peptic ulcer bleeding: A meta‐analysis

Background and Aims: In the management of peptic ulcer bleeding, the benefits of second‐look endoscopic treatment with thermal coagulation or injections in controlling recurrent bleeding is unsure. This study set out to compare efficacy of routine second‐look endoscopy with treatment using either thermal coagulation or injections versus single endoscopy by pooling data from published work. Methods: Full publications in the English‐language published work as well as abstracts in major international conferences were searched over the past 10 years, and six trials fulfilling the search criteria were found. Outcome measurements included: (i) recurrent bleeding; (ii) requirement of surgical intervention; and (iii) mortality. We examined heterogeneity of trials and pooled the effects by meta‐analysis. The quality of studies was graded according to the prospective randomization, methods of patient allocation, the list of exclusion criteria, outcome definitions and the predefined salvage procedures for uncontrolled bleeding. Results: Among 998 patients recruited in these five randomized trials, 119 received routine second‐look endoscopy with thermal coagulation, and 374 received second‐look with endoscopic injection and 505 had single endoscopic therapy. Less recurrent bleeding was reported after thermal coagulation (4.2%) than single endoscopy (15.7%) (relative risk [RR] = 0.29; 95% confidence interval [CI] = 0.11–0.73), but no reduction was reported for the requirement of surgical intervention and all‐cause mortality. Injection therapy did not reduce re‐bleeding (17.6%) when compared to single endoscopy (20.8%; RR = 0.85; 95% CI = 0.63–1.14), requirement for surgery and mortality. Conclusion: Routine second‐look endoscopy with thermal coagulation, but not injection therapy, reduced recurrent peptic ulcer bleeding. There is no proven benefit in reducing surgical intervention and overall mortality.     

Safety in the Work Place,Coshh and the Veterinary Nurse

Abstract

In small animal first opinion practice we occasionally see patients of the furless and legless variety. Often portrayed as the ‘stuff of nightmares’ our serpent friends have a bad reputation, and, formost, are not at the top of the list of our favourite animals. Unfortunately, the majority of the reptilian patients that grace our surgeries have fallen foul of poor basic husbandry, which is left for us to discover and fix. This article aims to give a basic guide to hospitalising some of the more common reptile species seen in veterinary practice and addresses the essential questions that need to be asked on admission as taking a detailed history of the husbandry is an essential part of the diagnostic process. .     

OSA microarray reader instrumentation and its applications for registration of on-chip real-time reactions

New applications of microarray technology requires new approaches to microarray reader development. Miniaturization of the biochips, necessity of massive parallel microarray-based analysis of various biological samples as well as increasing application of different real-time on-chip reactions for research and diagnostics demand improvement of microarray reader instrumentation. We represent the optical scanning array (OSA) reader system, allowing fast capture of high-resolution multifluorescence images and equipped with thermocontrolled hybridization chamber which is required for registration of a wide range of on-chip real-time processes. We demonstrate the application of OSA microarray reader for optimisation of hybridization and washing conditions for microarray-based detection of Q493X mutation of CFTR gene. It was shown that detailed analysis of on-chip thermodynamic and kinetic behaviour of oligonucleotide/oligonucleotide and ssPCR/oligonucleotide duplexes is very helpful for optimisation of experimental procedure.     

聚酰胺酸齐聚物改性环氧树脂

以3,3′,4,4′-二苯醚四羧酸二酐和4,4′-二氨基二苯醚为原料合成了以三聚体为主的聚酰胺酸齐聚物（PAA-n）。通过红外光谱、差示扫描量热分析、电喷雾质谱对其进行了表征。用PAA-n作为环氧树脂的反应性改性剂,研究了PAA-n改性环氧树脂的热性能和力学性能。结果表明:合成产物为目标产物,与环氧树脂有很好的化学反应性和相容性,在合适的配比和固化机制下,改性后树脂体系的热性能有所改善,力学性能也有较大的提高。     

低温核供热堆辐射防护安全准则

作者提出了低温核供热堆辐射防护安全准则的建议，即①要求半径５０ｋｍ范围内加权人口不超过１０６；②禁区半径为２５０ｍ；③限制发展区半径２ｋｍ；④低温核供热堆正常运行期间，由于放射性向环境释放所致公众个人剂量（全身或有效）不应超过０．１ｍＳｖ／ａ，集体剂量不超过１００ｍａｎ·Ｓｖ／ａ；⑤低温核供热堆事故期间，公众个人剂量不超过５ｍＳｖ，集体剂量不超过１０００ｍａｎ·Ｓｖ；⑥低温核供热堆正常运行期间，放射性流出物（气体、液体）的释放量不应超过国标ＧＢ６２４９规定值的２／５；⑦热网水中的放射性活度不应超过０．３７Ｂｑ／Ｌ；⑧建议应急状态分为三级，即应急待命、厂房应急和场区应急。