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.     

宝鸡市城市饮用水与人群健康效应的调查研究

本文通过对宝鸡市居民饮自来水和自备井水的人群进行了回顾性和前瞻性调查分析，结果发现，饮自来水与饮未经处理自备井水明显的差异。即调查组（饮自来水）肠道传染病发病率为４．２２％和６．８２％，对照组（饮自备井水）发病率为７．７１％和１１．５６％经卡方检验Ｐ＜０．０５，差异有显著性。从发病病种来看，调查组和对照组均以腹泻为主，其次为痢疾和肝炎，发病率分别是：腹泻，调查组为３５．５９‰和６３．００‰，对照组     

光催化剂对病房空气中细菌的作用

为了解光催化剂对病房空气中细菌消除效果 ,用平板沉降法采样进行了实际观察。结果 ,将 3盆涂抹有光催化剂的绢花放于可见光照的病房内 (2 3m3 ) ,4 8h后空气中自然菌菌数平均下降率为 2 5 .2 4 % ;12 0h后 ,平均下降率为 5 8.95 %。停止使用光催化剂之后 ,空气中细菌数恢复到原来水平。 15个病房内放置含光催化剂绢花 ,4 8h后有 6个病房无效 ,放置 12 0h后仍有 4个病房无效。结论 ,光催化剂对病房空气中细菌消除效果达不到卫生要求 ,只有部分房间显示出一定消除效果。     

CY消毒湿面巾消毒效果的实验研究

以LJ-强化戊二醛为主体制成的CY消毒液。能快速杀灭细菌,10min内可灭活HBsAg,在有效浓度范围内不会对人体产生危害,应用安全可靠。以其制成湿面巾擦拭手、碗、筷2min,可将实验菌及自然菌减少99％,其细菌残留数均<30个/cm~2。拭后纸上无细菌残留,其丢弃物不会污染环境。室温下(35～39℃)放置3个月的CY湿面巾,外观无改变,消毒效果稳定。     

HQJ-500多功能净水装置装舰试用评价

目的：改善舰船官兵的饮用水水质，提高舰员的生活质量。方法：将研制的HQJ-500多功能净水装置装舰试用，征求试用意见并进行水质分析。结果：经实船试用证实，该多功能净水器能经受住各种海况下颠簸，摇晃的考验。运行正常。处理后的水质有明显改善。结论：该装置净化，消毒效果肯定，适合舰船使用，可推广应用。     

加味五味消毒饮对鼻窦炎手术后疗效观察

目的:观察加味五味消毒饮冲洗液鼻腔冲洗对慢性鼻窦炎鼻内镜手术(FESS)术后的临床疗效及黏膜修复的影响.方法:对60例Ⅱ型慢性鼻窦炎患者,在鼻内镜手术后,治疗组用自拟加味五味消毒饮冲洗液冲洗术腔,对照组以常规的西药冲洗液冲洗术腔,随访6个月,比较两组的疗效.结果:治疗组的治愈率、总有效率分别与对照组比较,差异均有统计学意义(P＜0.05).且治疗组鼻腔修复时间明显短于对照组,提前结束治疗病例数有明显差异(P＜0.05).结论:中药配方加味五味消毒饮冲洗液进行鼻腔冲洗,能缩短鼻黏膜修复时间,提高临床疗效.     

2%戊二醛在根管治疗中的应用

应用戊二醛、甲醛甲酚消毒感染根管各80例，观察其细菌学培养情况，结果表明戊二醛消毒根管后细菌培养阳性率4％，甲醛甲酚消毒根管后细菌培养阳性率为18％，说明戊二醛对感染根管的消毒作用显著优于甲醛甲酚消毒剂。     

婴儿培养箱基本性能研究与改进

根据对婴儿培养箱多年的临床使用与维修体会,阐述了婴儿培养箱基本性能要求,并指出现行的此类设备存在的问题,及具体改进方法。     

TD清洗消毒剂对口腔科器械消毒效果探讨

通过实验室和口腔科临床观察表明:TD清洗消毒剂(氯化磷酸三钠)对金黄色葡萄球菌、绿脓杆菌和枯草杆菌黑色变种的平均杀菌率为100.0％,对口腔科器械消毒无菌率为100％,对被HBsAg阳性血清污染的器械浸泡30分钟转阴率为98.1％。其消毒效果优于新洁尔灭,与戊二醛相同。在口腔科使用两年,未见金属器械有锈斑生成。