Increased concentrations of octachlorodibenzo-p-dioxin in cases with breast cancer--results from a case-control study

Organochlorines are persistent and highly lipophilic environmental contaminants which bioaccumulate in the food chain. Some of these chemicals, 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) and polychlorinated biphenyls (PCBs), have been suggested to be of significance in the aetiology of breast cancer. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an anti-oestrogen in animal studies and should be thus lower the risk of breast cancer. The other isomers of polychlorinated dibenzo-p-dioxins (PCDDs) or the chemically related polychlorinated dibenzofurans (PCDFs) have not been tested regarding carcinogenesis of the breast. The purpose of this study was to investigate whether PCDDs or PCDFs influence the risk for breast cancer. Consecutive patients who underwent surgery for a breast disease between 1993 and 1995 were recruited for the study. Cases were 22 patients with infiltrative breast cancer and controls were 19 patients operated for a benign breast disease during the same time period. Approximately 10 g of breast tissue free from tumour was taken from the specimen and frozen until analysis. Fat was extracted, cleaned and analysed with a high-resolution gas chromatograph coupled to a high-resolution mass spectrometer. Median concentrations of octachlorinated dibenzo-p-dioxin (OCDD) were 598 (170-14,880) and 396 (103-1,847) pg/g lipid in the cases and in the controls, respectively. In a multivariate logistic regression analysis controlling for other risk factors for breast cancer increased odds ratio (OR) was obtained for OCDD: 401-1000 pg/g lipid yielded OR 3.8, 95% confidence interval (CI) 0.4-39, > 1000 pg/g lipid gave OR 5.2, CI 0.4-72. When the lipid OCDD variable was examined as a continuous risk factor there was a 1.09 (9%), CI 0.95-1.25, increase in the adjusted OR for breast cancer per 100 unit (pg/g lipid) increase in OCDD. No differences were found between cases and controls for the other six tested PCDDs. Mean concentration of TCDD was in the cases 3.6 (1.0-7.9) and in the controls 3.3 (1.1-6.3) pg/g lipid. For PCDFs no significant differences were found between cases and controls. The results were not changed if oestrogen or progesterone receptor status, S-phase fraction and DNA ploidy were considered. Breast tissue concentration of OCDD was increased in cancer patients, whereas the concentrations of other PCDDs and PCDFs were equal in cases and controls.     

孤岛油田西区聚合物驱开发研究

孤岛油田西区注聚区1997年3月投入注聚后，高渗层得到有效封堵，吸水剖面得到明显改善。注聚期间，通过实施注聚区外围水井降水或停注、油井放大生产压差和调整注聚井注入速度等开发措施，扩大了聚合物波及体积，聚合物驱取得了明显效果。     

HPMBP与伯胺N_(1923)对希土元素(Ⅲ)的协同萃取

本文研究了HPMBP与伯胺N_(1923)的二甲苯溶液,从盐酸介质中协同萃取希土(Ⅲ)的机理。用斜率法、恒摩尔法确定了协萃配合物的组成为:RNH_3Ln(PMBP)_4。求得关于Pr(Ⅲ)协萃反应的平衡常数及协萃配合物的生成常数分别为:logK_(12)=-1.95;logβ_(12)=3.94。实验发现,协萃系数(R)随希土元素的原子序数(Z)递变而呈现“双峰效应”。还研究了协萃配合物的IR,NMR谱。