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     

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。     

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。     

紫外线对两种聚四氟乙烯电荷储存稳定性的影响

利用在室温下的栅控恒压电晕充电后经不同强度紫外线辐照的表面电位测量,研究了紫外线对聚四氟乙烯(polytetrafluoroethylene,PTFE)多孔膜、聚四氟乙烯非多孔膜驻极体电荷储存稳定性的影响,探讨了两种聚四氟乙烯驻极体医疗产品使用紫外消毒方法的可行性.结果:(1)在常温条件下,紫外线辐照对两种聚四氟乙烯驻极体的电荷储存稳定性的影响不大;(2)聚四氟乙烯多孔膜驻极体的电荷储存能力随环境湿度的提高而略有下降;(3)聚四氟乙烯医用驻极体产品可采用紫外消毒法消毒.     

Coronavirus disinfection in histopathology

ABSTRACT

The 2019 Coronavirus epidemic, provisionally called 2019-nCoV, was first identified in Wuhan, China, in persons exposed to a seafood or wet market. There is an international push to contain the virus and prevent its spread. It is feasible that potentially infectious samples may be received in histopathology laboratories for diagnosis. This technical note presents disinfection procedures and histotechnology processes that should alleviate the risk of infection to laboratory staff. Using data obtained from similar coronaviruses, e.g. severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), experts are confident that 70% ethanol and 0.1% sodium hypochlorite should inactivate the virus. Formalin fixation and heating samples to 56oC, as used in routine tissue processing, were found to inactivate several coronaviruses and it is believed that 2019-nCoV would be similarly affected.     

微酸性电解水实验室微生物杀灭效果研究

 目的 研究某微酸性电解水实验室微生物杀灭效果。方法 选取某次氯酸水发生器现制微酸性电解水,测定不同有效氯含量、不同作用时间其对细菌繁殖体、芽孢以及真菌的杀灭效果。结果 该微酸性电解水有效氯含量为34.3~118 mg/L,有机干扰物牛血清白蛋白浓度为3.0%和0.3%时,分别作用1.0、3.0、5.0、10.0 min,对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌的平均杀灭对数值均>5.00,对白假丝酵母菌的平均杀灭对数值均>4.00;有效氯含量为101~118 mg/L,牛血清白蛋白浓度为0.3%时,分别作用5.0、10.0、30.0 min,对枯草杆菌黑色变种芽孢的平均杀灭对数值均>5.00。结论 在特定实验条件下,该微酸性电解水对细菌的繁殖体、芽孢以及真菌均达到消毒剂消毒合格标准。