Quantification of human amniotic fluid constituents by high resolution proton nuclear magnetic resonance (NMR) spectroscopy

We have investigated the ability of high-resolution proton NMR spectroscopy to provide a biochemical constituent screening of human amniotic fluid (AF). Proton NMR spectra were obtained at 300 MHz on AF from patients undergoing amniocentesis in the mid-trimester. Only AF from normal pregnancies (normal fetal karyotype, normal a-fetoprotein levels, normal birth outcome) was used in this study. The AF supernatant was lyophilized and resuspended in deuterated water containing 0.1 mm phosphate buffer and 6.02 mm disodium maleate. Identification of low molecular weight compounds was confirmed by two-dimensional NMR spectra (primarily correlated spectroscopy, or COSY) and standard addition techniques. A broad profile of compounds were ‘NMR visible’ in a single proton spectrum, including creatinine, glucose, organic acids (acetate, citrate, and lactate) and several amino acids (alanine, histidine, leucine, phenylalanine, tyrosine and valine). The proton spectrum was unaffected by prior freezing/thawing of AF samples. We were able to quantify compounds by comparison with an added concentration standard (maleate) at concentrations as low as 30 μm. Good agreement with literature values based on other analytical techniques was obtained.     

石英表面配合物与溶解动力学模型

阐述了石英表面配合物和溶解动力学机理之间的关系，指出了石英的反应性主要受负电性表面物种的控制，从而导致电解质、离子强度、pH等因素对石英溶解的催化效应．溶解达率的提高与反应活化能的降低成活化熵的增大有关。最后，介绍了在过渡态理论和表面反应模型基础上建立的石英溶解速率方程。     

新农药环境化学行为研究(V)-—三氟羧草醚(Acifluorfen)在土壤和水环境中的滞留、转化

从如下几方面研究了三氟羧草醚在土壤－水环境中的化学行为：一是土壤对该药的吸附，结果表明，吸附强度与土壤理化特性密切相关，Ｆｒｅｕｎｄｌｉｃｈ常数ｋｆ＝０．９４Ｗｏｍ＋０．６５Ｗｃｌａｙ－９．５９ｐＨ（ｒ＾２＝０．９４）；二是吸附机理研究，发现三氟羧草醚能与碱金属以外的许多金属离子形成配合物，并证实了与ＣＵ＾２＋形成的双核桥联合物的可能性；三是实验指出它在水中避光有一定的稳定性，不易水解；四是它在〈     

广东核电站厂址降水特征分析

介绍广东核电站厂址降水特性分析的方法学，给出降水的气侯学统计以及降水率、降水持续时间的分布特征．     

Prenatal diagnosis in two cases of de novo complex balanced chromosomal rearrangements. Three-year follow-up in one case

We report two cases of apparently balanced complex de novo chromosomal rearrangements (BCCR) detected prenatally at 17 weeks and 10 weeks of gestation, respectively. Chromosomes were studied using GTG-banding and fluorescent in situ hybridization (FISH). In one case four chromosomes and in the other case three chromosomes were involved in the rearrangements. One of the pregnancies was terminated and no external or internal abnormalities were detected at autopsy. The other pregnancy continued to term. Level III ultrasound examination showed no abnormalities. The child is now 3 years old and has neither congenital anomalies nor evidence of delayed psychomotor development.     

Complex behaviour of trivalent rare earth elements by humic acids

ＣｏｍｐｌｅｘｂｅｈａｖｉｏｕｒｏｆｔｒｉｖａｌｅｎｔｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｂｙｈｕｍｉｃａｃｉｄｓＧｅｎｇＡｎｃｈａｏＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＥｎｖｉｒｏｎｍｅｎｔａｌＥｎｇｉｎｅｅｒｉｎｇ，ＦｕｓｈｕｎＰｅｔｒｏｌｅ...     

复介电常数在水土污染监测中的应用研究

采用短路同轴线法测量了淀粉聚乙烯醇共混体样品,在含水率、离子浓度不同时的复介电常数,研究了频率、离子浓度、含水率与相对复介电常数的关系。结果表明,淀粉PVA复介电常数的实部对含水率很敏感,虚部在500~700MHz频段随含盐量升高呈对数增加,这为利用测量相对复介电常数进行水土系统离子污染监测,提供了可能和实验依据。     

水杨酸甲酯废渣的初步分析

通过红外光谱和核磁共振方法分析生产水杨酸甲酯时所产生的废渣的主要在分，得出主要成分是４－羟基－１，３－苯二甲酸二甲酯的讨论。该化合物在药物合成上一定的用途。     

生活污水对蝌蚪红细胞微核及核异常的诱导

利用青蛙蝌蚪红细胞微核试验,检测了城市生活污水处理厂各级处理工艺出水的诱变活性。在l6d生话污水处理的实验中,青蛙蝌蚪红细胞微核细胞率及核异常率2d后就呈现统计上的显著增加,并随暴露时间的延长而增高,第8天达到最大值。在不同浓度混合污水暴露实验中,蝌蚪红细胞微核细胞率和核异常率呈现明显的剂量依赖性增加。实验结果表明:城镇生活污水具有较强的诱变活性,一级和二级处理工艺出水也具有一定的诱变活性。现有污水处理工艺有待于进一步改进。     

Fetal translocation between chromosomes 2, 18, and 21 resolved by fish

An apparently balanced t(2q;21q) translocation was discovered in fetal blood and amniocytes of a 22-week fetus, monitored because of ultrasonographic evidence of a heart disease. FISH (fluorescence in situ hybridization) analysis disclosed a complex translocation between chromosomes 2q, 18q, and 21q, which was inherited from the healthy mother. This observation corroborates the usefulness of molecular cytogenetic techniques in raising the quality of prenatal diagnosis and detecting subtle rearrangements not resolved by standard cytogenetics.