Synthesis of 13C-labeled parabens from isotopically enriched phenols using the Houben–Hoesch reaction

Parabens are antimicrobial additives found in a wide array of consumer products. However, the halogenated compounds formed from parabens during wastewater disinfection are a potential environmental concern. In order to identify these transformation products and investigate their mechanism of formation, a synthetic route to ethyl parabens labeled with the stable isotope carbon-13 at specific positions within the benzene ring was developed. This efficient two-step procedure starts from commercially available ¹³C-labeled phenols and involves (1) initial acylation of the phenol via a Houben–Hoesch reaction with trichloroacetonitrile followed by (2) a modified haloform reaction of the resulting trichloromethyl ketone to afford the corresponding ¹³C-labeled ethyl parabens in 65%–80% overall yield. The scope of the modified haloform reaction was also investigated, allowing for the synthesis of other parabens derived from primary or secondary alcohols, including ¹³C- and deuterium-labeled esters. In addition, 4-hydroxybenzoic acid can be formed directly from the common trichloromethyl ketone intermediate upon treatment with lithium hydroxide. This protocol complements existing methods for preparing ¹³C-labeled paraben derivatives and offers the specific advantages of exhibiting complete regioselectivity in the Houben–Hoesch reaction (to form the para-disubstituted product) and avoiding the need for protecting groups in the modified haloform reaction that forms the paraben esters.     

活血利水法在骨伤科疾病中的应用

基于骨伤疾病瘀血内阻的重要病机和现代医家"治血重治水"的学术观点,探索概括了活血利水法在骨伤疾病中的应用现状,结合现代医学的认识,全方位分析了活血利水法的优势和缺点。活血利水法可应用于骨折、筋伤等骨伤科大部分疾病及骨伤科疾病的围手术期,能改善肢体肿胀,促进伤口愈合,便于患者早期功能康复,但目前的临床应用尚缺乏统一的规范和标准,且处方不良反应尚未完全阐明。     

酸性氧化电位水在临床伤口治疗中的应用效果

摘要：目的 观察和比较酸性氧化电位水在临床伤口治疗中的作用与效果。 方法 将四川大学华西医院伤口治疗中心2018年3月至2019年1月接诊的慢性伤口患者随机分为观察组和对照组，观察组使用酸性氧化电位水设备生产的酸化水冲洗创面，对照组使用无菌生理盐水冲洗创面，并连续两周留取伤口分泌物涂片镜检。患者创面根据我院伤口治疗处理规范，采用标准湿性疗法，每组患者观察伤口治疗效果3周，观察指标：伤口床细菌种类及数量变化、伤口疼痛评分、伤口愈合计分、伤口治愈率及治愈时间。 结果 两组液体冲洗后，创面细菌种类及数量均有改变，观察组较对照组更为显著（P＜0.01）。两组PUSH评分数周治疗后均可见显著下降，尤以观察组下降更为明显（P＜0.05）。观察组伤口明显缩小（P<0.05）。观察组治愈率高于对照组( 74.41% vs 48.48% ， P ＜0.05) ，愈合时间缩短 13 d( P＜0.05) 。 结论 酸化水通过高效的杀菌能力，提供清洁的创面微环境，有效地促进伤口愈合，提高伤口治愈率，缩短伤口治愈时间，但不会增加患者的疼痛体验，可作为常规的创面冲洗液。     

The Using of Concrete Wash Water from Ready Mixed Concrete Plants in Cement Systems

Concrete plants accumulate large amounts of concrete wash water. This water, which pH is highly alkaline, has a negative impact on the environment. Its reuse in fresh concrete slightly reduces its mechanical properties. The combination of concrete wash water and zeolitic by-product led to an increase of 4.6% in the compressive strength at 7 days hydration and up to 30% at 28 days hydration. The same combination led to the denser microstructure compared to the samples made with concrete wash water. This could be explained by the pozzolanic reaction of the zeolitic by-product. The complex chemical reactions of cement, zeolitic by-product, and fines presented in the concrete wash water occurred. Therefore, it was suggested the reusing method of concrete wash water together with zeolitic by-product in the fresh concrete mixtures by substituting some amount of tap water with concrete wash water. In this way, the consumption of tap water is possible to reduce in cement systems.     

透析用水内毒素含量检测数据调查研究分析

目的符合透析治疗安全的透析用水是血液透析日常治疗开展的基本保障,根据统计分析内毒素含量的变化规律,探索控制透析用水内毒素含量的管理方式。方法对上海市21家血液净化中心(室)2019年3月至2020年2月期间透析用水的内毒素(endotoxin,ET)含量数据进行汇总与统计分析。结果透析用水内毒素含量在全年的春季与夏季中会存在部分偏高的情况,其中春季送检的样本中,ET含量>0.25 EU/ml比例占当季送检样本的0.57%,ET含量在0.03~0.25EU/ml之间的比例占7.34%;在夏季送检的样本中,ET含量>0.25EU/ml比例占当季送检样本的1.13%,ET含量在0.03~0.25EU/ml之间的比例占3.39%,与秋冬两季水平相比,差异有统计学意义(F=11.392,P值<0.001)。结论严格管控透析用水生产、输送过程的每个环节,规范采样流程、加强反渗机日常维护管理、重视水处理系统及配管的日常消毒等措施可减少血液透析相关的不良反应发生,提高患者透析质量。