某纯碱生产企业职业病危害因素现状调查与评价

目的 了解某纯碱生产企业存在的职业病危害因素和采取的职业病危害防护措施,为职业病防治工作提供依据。方法 采用现场职业卫生学调查和工作场所职业病危害因素检测方法,进行职业卫生现况调查分析。结果 粉尘、氨气、碳酸钠、一氧化碳、氯化氢、硫化氢、噪声、高温为该厂存在的主要职业病危害因素,其中粉尘超标率为21.2%、氨气超标率为14.9%、碳酸钠超标率为13.8%、噪声超标率为11.8%,氯化氢、硫化氢、高温均符合国家卫生标准要求。结论 该企业采取的职业病危害防护措施基本可行,职业卫生管理体系较为完整,职业卫生管理水平较高,但某些职业病危害因素存在超标点,应着重改善作业环境,提高防护措施,控制有害因素的浓度和强度,防止职业病的发生。     

Increased Ash Contents and Estimation of Dissolution from Chemical Changes due to In-Vitro Fluoride Treatments

The in-vitro fluoride treatment technique has been introduced to investigate the composite behavior of bone tissue. Bone tissue with different mechanical properties can be obtained by varying the concentration, pH and immersion time in fluoride ion solutions. The chemical and physical changes in intact pieces of bone treated in-vitro with different concentrations of fluoride ions are studied. The amount of bone mineral that does not contribute to the mechanical behavior of bone tissue is estimated from the dissolution occurring in the fluoride treated bones. Cortical bones from 18-month-old steers were treated in-vitro with 0.145, 0.5 and 2.0M sodium fluoride (NaF) solutions for three days. The dissolved bone mineral precipitates as calcium fluoride-like (CaF 2 /P with some phosphate [P] ions) and fluorapatite(FAp)/fluorhydroxyapatite-(FHAp)-like materials within the bone tissue. The dissolution estimated from the presence of the precipitated fluoride phases is 5.6, 11.7, and 13.1% of the initial bone mineral content for the 0.145M, 0.5M, and 2.0M NaF treatments respectively. Estimates of dissolution based on the measurements of phosphate and carbonate ions are lower and higher respectively when compared to the fluoride ion measurements. The wet and dry densities decreased slightly due to dissolution and re-precipitation while the ash content (ratio of the ash weight to dry weight) increased a small amount with increasing concentration of fluoride ion treatments. The increased ash content was due to the excess loss of water in the fluoride treated bones as compare to controls (untreated bone samples) during the drying process. The increased removal of water during the drying process may explain the increased ash contents in some in-vivo treatments.     

Optimization of low activity spectrometric gamma–gamma probes for ash determination in coal stockpiles

A stockpile probe based on backscattered gamma–gamma-ray technique was tested for the determination of coal ash. A centralized tool employing a gamma-ray source of very low radioactivity (1.85 MBq) was used. This logging tool was tested using ¹³⁷Cs and ¹³³Ba sources with a 37 mm (diameter) by 75 mm NaI (TI) scintillation detector. Ten source–detector configurations were analyzed using ¹³⁷Cs, and another nine source–detector configurations are analyzed, using ¹³³Ba source, both for four geophysical models, having a borehole diameter of 90 mm. Regression analysis on the laboratory logging data for each studied configuration was carried out in order to establish calibration equations for ash prediction. The optimum configuration for the logging stockpile probe using ¹³⁷Cs source was determined to be 80 mm source to detector spacing, and 80 mm iron thickness shielding. This configuration gives the best results for ash prediction. The root mean square (rms) deviation for ash is 1.52%. The optimum configuration for the logging stockpile probe using ¹³³Ba source is determined to be 85 mm source to detector spacing, and 50 mm iron thickness shielding. This configuration gives the best results for ash prediction, where the rms deviation for ash is 1.47%.     

秦皮提取物对小鼠急性肝损伤保护作用的实验研究

目的研究秦皮提取物对四氯化碳所致小鼠急性肝损伤的保护作用。方法60只雄性昆明小鼠随机分为正常对照组,模型对照组,阳性对照组,大?中?小剂量给药组。大?中?小剂量给药组分别按2.0,1.0,0.5 g/kg灌胃秦皮提取物;阳性对照组按0.1 g/kg灌胃水飞蓟宾;正常对照组和模型对照组以等体积生理盐水灌胃,共6 d。第5天,模型对照组、阳性对照组和给药组按2.0 m l/kg腹腔注射CC l4,正常对照组腹腔注射等体积生理盐水。比较各组丙氨酸氨基转移酶(alan ine transam inase,ALT)?超氧化物歧化酶(superoxide d ismutase,SOD)和丙二醛(m alond ialdehyde,MDA)含量。结果秦皮提取物能显著降低四氯化碳所致小鼠各组ALT含量的升高(P<0.05),同时能升高SOD的活性,降低MDA的含量(P<0.05)。结论秦皮提取物对四氯化碳所致小鼠急性肝损伤具有一定的保护作用。