新型粘结固定桥临床应用初步观察

目的 观察一种用于牙列缺损永久修复的新型粘结固定桥的临床效果。方法 选择有单个或多个牙缺失的病人，进行固定桥基牙的牙周和特定的牙体预备。然后制作固定桥并试戴，用4－META／MMA－TBB树脂粘结剂粘结固定桥。结果 267例（304个）固定桥病人经二年以上随访，发现192个前牙桥中只有1个，112个后牙桥中只有2个脱落，其余固定桥稳定、功能良好。结论 采用树脂粘接技术，结合基牙的机械预备，能较好地克服3／4冠桥、桩冠桥和嵌体桥的缺陷，使之成为良好永久的修复体。     

胜利黄岛原油深度电脱盐的研究：Ⅰ.破乳剂组成的影响

根据胜利黄岛原油的性质，在筛选了几十种破乳剂的基础上，选择了酚醛树脂和环氧环烷，环氧乙烷的嵌段共聚物作破乳剂，探讨了破乳剂组成对原油脱水，脱盐以及界面张力的影响，通过静态脱盐，脱水试验，得到了适合黄岛原油的最佳破乳剂组成。     

Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin

The objective of this work was to establish a new procedure for ²²⁸Ra determination of natural waters via preconcentration of radium on MnO₂ and separation of its daughter, ²²⁸Ac, using Diphonix ion exchange resin. Following removal of potential interferences via passage through an initial Diphonix Resin column, the first daughter of ²²⁸Ra, ²²⁸Ac, is isolated by chromatographic separation via a second Diphonix column. A holding time of >30 h for ²²⁸Ac ingrowth in between the two column separations ensures secular equilibrium. Barium-133 is used as a yield tracer. Actinium-228 is eluted from the second Diphonix Resin with 5 ml 1 M 1-Hydroxyethane-1,1-diphosphonic acid (HEDPA) and quantified by addition of scintillation cocktail and LSC counting. Radium (and ¹³³Ba) from the load and rinse solutions from the 2nd Diphonix column may be prepared for alpha spectrometry (for determination of ²²³Ra, ²²⁴Ra, and ²²⁶Ra) by BaSO₄ microprecipitation and filtration. Decontamination tests indicate that U, Th, and Ra series nuclides do not interfere with these measurements, although high contents of ⁹⁰Sr (⁹⁰Y) require additional treatment for accurate measurement of ²²⁸Ra. Addition of stable Sr as a “hold back” carrier during the initial MnO₂ preconcentration step was shown to remove most ⁹⁰Sr interference.     

接枝环氧树脂水分散液的合成、分离与表征

控制不同的反应条件,采用甲基丙烯酸、苯乙烯与环氧树脂在丙二醇丁醚/正丁醇溶剂中接枝共聚,合成了粒径在87～104nm范围的环氧树脂水分散液。通过环己烷/乙醇和丙酮两步萃取,对接枝共聚产物进行分离,用FTIR表征,并估算了接枝共聚物的组成。实验结果表明,所制备的粒径为纳米级的环氧树脂水分散液,具有良好的机械稳定性、冻融稳定性及贮存稳定性。ξ电位测定表明,产物在pH>8的条件下更为稳定。     

Dermatitis from hexavalent chromate in the accelerator of an epoxy sealant (PR1422) used in the aircraft industry

4 aircraft construction workers developed allergic contact dermatitis of the hands and forearms. The allergen was hexavalent chromate in the accelerating solution of an epoxy-based sealant (PR1422). Although chromate dermatitis from an epoxy resin has been described, epoxy system accelerators are a hitherto unrecognized source of occupational chromate dermatitis.     

Occupational allergic contact dermatitis and composition of acrylates in dentin bonding systems

Background Dentin-bonding systems contain sensitizing acrylates. They are increasingly used in dentistry, but only few cases of allergy have been encountered. Objective This study reports observations on eleven patients sensitized by acrylates in dentin-bonding compounds. Furthermore, the composition of dentin-bonding products was analysed and compared with the information given in the material safety data sheets. Methods Patch testing was performed to reveal allergic contact dermatitis, and chamber provocation tests to reveal possible respiratory sensitivity. Gas chromatography/mass spectrometry was used to analyse the chemical composition of the bonding products. Results The most common sensitizer in our material of eleven patients was 2-hydroxyethyl methacrylate (2-HEMA). Another putative sensitizer, BIS-GMA, used in dentin adhesives, did not cause sensitization. The typical allergic dermatitis localized to the fingertips (pulpitis). Seven of the eleven patients also developed paresthesia of the fingertips. One patient with positive patch test reactions to (meth)acrylates had pharyngitis hut no skin symptoms. One patient was sensitized because she had been patch tested with too high a concentration (undiluted) of dentin-bonding components. Material safety sheets gave inaccurate or wrong information about the contents. Conclusion Dentin-bonding acrylates are strong sensitizers, and even a single exposure may sensitize.     

复合树脂预热的研究现状和临床应用

复合树脂作为临床常用牙科充填材料存在耐磨性差、聚合收缩大和牙本质边缘适应性不佳等问题。近年有研究发现预热可以改善复合树脂的性能,本文就预热复合树脂对其单体转化率、边缘微渗漏、机械性能以及牙髓的影响等方面进行探讨,以供临床参考。     

RRLC-UV法同时测定丹参中酚酸类成分的含量

目的:建立RRLC-UV法同时测定丹参药材中9种酚酸的含量.方法:以3,4-二羟基苯乙酸为内标,采用Agilent Zorbax Eclipse Plus C_(18)(2.1 mm×50 mm,1.8μm)色谱柱,以乙腈-0.1%甲酸溶液为流动相梯度洗脱,流速0.3 mL·min~(-1),检测波长质量286 nm.结果:这9种成分在测定质量浓度范围内与色谱峰面积线性关系良好,相关系数不低于0.999 5.仪器精密度和方法精密度RSD均小于2.4%,9种成分平均回收率在96.7%～102.6%,RSD均小于3.1%(n=3).结论:该方法简便、快速,结果准确,重复性好,适用于丹参药材的质量控制.