北京市政供水中三氯甲烷和四氯化碳含量分析及健康风险评估

目的了解南水北调之后北京市市政水中三氯甲烷和四氯化碳的浓度水平,评估其对人体健康的潜在风险。方法收集了2015—2019年北京市出厂水、末梢水和二次供水中三氯甲烷和四氯化碳的监测数据,利用美国环保局(USEPA)推荐的健康风险评价四步法模型对其进行健康风险评估。结果4292件监测水样中,三氯甲烷平均浓度为0.00300 mg/L,四氯化碳平均浓度为0.00062 mg/L,两种污染物的合格率均为100%。三氯甲烷和四氯化碳的致癌风险分别为3.23×10^-6、1.51×10^-7;非致癌风险分别为1.04×10^-2、5.39×10^-4。结论北京市市政水中四氯化碳的健康风险较小,三氯甲烷的健康风险属于可接受范围,但由于南水北调后水质变化较大,仍需要继续监测并提出风险管控措施。     

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.     

左旋肉碱修饰的壳聚糖-硬脂酸协载槲皮素口服紫杉醇纳米胶束的制备、表征及在体肠循环研究

目的 制备左旋肉碱修饰的壳聚糖-硬脂酸（LC-SA/CS-SA）纳米胶束，包载紫杉醇（PTX）且协载槲皮素，考察胶束特性，并以大鼠在体肠循环评估给药系统对PTX口服吸收的促进作用。方法 将硬脂酸（SA）通过酰胺化反应接枝于壳聚糖（CS），形成共聚物CS-SA；采用核磁共振H谱、红外光谱鉴定产物结构；以PTX为主药，槲皮素为辅药，采用激光粒径分析、Zeta电位分析和HPLC分析分别考察了胶束的粒径、Zeta电位、载药量、包封率；透射电子显微镜观察胶束形貌；芘荧光探针法测定LC-SA/CS-SA胶束的临界胶束浓度（critical micelle concentration，CMC）；透析袋法考察胶束的体外释放行为；大鼠在体肠吸收实验评估载药胶束的促吸收作用。结果 红外与核磁结果表明SA通过酰胺键接枝于CS；协载槲皮素的LC-SA/CS-SA载PTX胶束呈类球形，粒径为（148.3±1.7）nm，多分散系数（PDI）为0.16±0.07，Zeta电位为（24.600±0.167）mV，CMC为14.31 μg/mL；体外释放结果表明，与市售紫杉醇注射剂相比，协载槲皮素的LC-SA/CS-SA载PTX胶束、LC-SA/CS-SA载PTX胶束具有明显缓释效应；大鼠在体肠吸收实验表明，协载槲皮素的LC-SA/CS-SA胶束对载药PTX的胃肠吸收具有显著促进作用。结论 构建的协载槲皮素的LC-SA/CS-SA载PTX胶束性能优良，促进了PTX的大鼠肠吸收，具有增强药物口服吸收潜力。     

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。     

Oral levothyroxine therapy postbariatric surgery: Biopharmaceutical aspects and clinical effects

Background

Bariatric surgery can lead to changes in the oral absorption of many drugs. Levothyroxine is a narrow therapeutic drug for hypothyroidism, a common condition among patients with obesity.

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。     

Compressive Properties and Energy Absorption Characteristics of Extruded Mg-Al-Ca-Mn Alloy at Various High Strain Rates

This paper is focused on the mechanical properties and the energy absorption characteristics of the extruded Mg-Al-Ca-Mn alloy in different compression directions under high strain rate compression. Compressive characterization of the alloy was conducted from the high strain rate (HSR) test by using a Split Hopkinson Pressure Bar (SHPB). Results show that the investigated alloy exhibits a strong strain rate sensitivity. With the rise of strain rate, the compressive strength is increased significantly, and the deformation ability also improves. When compressed along the extrusion direction, as the strain rate increases, the total absorbed energy E, the crush force efficiency (CFE), and the specific energy absorption SEA of Mg-Al-Ca-Mn alloy are all greatly improved as compared with those obtained along other compression directions.