关于高矿化度矿井水对生态环境的影响及防治对策

1 矿区概况 永夏矿区属华北晚古生界聚煤区,含煤地层主要为石炭二迭系。 区内地下水发育,按其岩性、地质年代及富水性,可分为第四系孔隙潜水、第三系孔隙承压力、上二迭裂隙承压水、上石炭系岩溶高承压水及奥陶系岩溶高承压水等五个含水层。第四系浅层地下水分布广泛,沉积稳定,富水性较强,渗透性能好。水位埋     

高邮市基本农田环境质量监测与评价

根据近两年高邮市试点工作经验，介绍基本农田分等定级的环境监测与评价方法，认为积极开展农田环境监测并进行科学评价是基本农田保护的重要工作内容。     

用煤矸石制取水玻璃的研究

本文研究了用煤矸石制取水玻璃的可行性，利用正交试验，研究了焙烧温度、焙烧时间、反应温度、ＮａＯＨ浓度、渣样粒度等因素对制取过程的影响，确定了最佳操作条件。     

Vitamins,folic acid and neural tube defects: Comments on investigations in the United States

No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S.     

Evaluation of inorganic pyrophosphate in amniotic fluid as a mode of prenatal diagnosis of osteogenesis imperfecta

Using a modified procedure by Solomons and Styner (1969), an evaluation of inorganic pyrophosphate (PPi) was performed on the amniotic fluid of two fetuses at risk for osteogenesis imperfecta (OI) at 14½ weeks gestation. The parents of both cases had a previous child with OI, Type II. The normal control group at 14–16 weeks gestation had PPi values ranging from 22.0–59.2 ug/100 ml, with a mean of 38.6±9.51 ug/100 ml. In each at-risk fetus, the amniotic fluid PPi value was within normal range. The first baby was born phenotypically normal at term. Intrauterine radiographic and fetal sonograms were done on the second fetus at approximately 19 weeks gestation. Both showed evidence of OI, Type II. The pregnancy was terminated at 21 weeks. Radiologic studies of the aborted fetus were consistent with OI, Type II. Our results indicate that the evaluation of PPi levels in amniotic fluid is not the method of choice for prenatal diagnosis of IO.