壬基酚聚氧乙烯醚在污水处理过程中的迁移转化行为

用正相色谱－质谱联用法（NPLC－MS）分离分析高聚合度的NPnEO(n＞2）,用气相色谱－质谱联用方法（GC－MS）测定其中的NP,NP1EO和NP2EO浓度,对NPnEO在城市污水处理厂的迁移转化行为进行了研究。在污水处理厂的进水中,检测出NP和NPnEO(n=1-23）,总浓度为174nmol/L,其中NP2EO的浓度最高,为89．6nmol/L;其次分别为NP（42．2nmol/L）和NP1EO（12．2nmol/L）;出水中同样检测出NP和NPnEO(n=1-18),其中NP2EO的浓度最高,为37．2nmol/L;其次分别为NP（6．64nmol/L）和NP1EO（0．135nmol/L)。在城市污水处理过程中,NPnEO从高聚合度降妥成低聚合度,NP和NPnEO的总去降率为71％。另外,NP和NPnEO在污泥及污泥过滤水中的分配表明污泥对NPnEO有明显的吸附作用,并近似符合Dubinin-Astakhov等温吸附。     

First-trimester prenatal diagnosis in quintuplets: A practical approach using step-by-step embryo reduction

A multiple pregnancy of high rank may occur in a couple at risk for a Mendelian disorder. Prenatal diagnosis is hampered by the difficulty of (1) obtaining chorionic villi from each zygote arid (2) unequivocally relating each sample to the corresponding embryo. The calculation of the genetic risk according to the number of zygotes led us to propose a diagnostic strategy based on embryo reduction, a technique initially designed to improve the perinatal outcome of multiple pregnancies with normal embryos. We report a case in which this approach allowed rational use of first-trimester chorionic villus sampling in a quintuplet pregnancy at risk for non-ketotic hyperglycinaemia, resulting in the selective birth of unaffected twins.     

石英羟基水-分子水的分馏系数与常规混合水δD分析的关系

采集了 4个不同地区花岗岩石英、热液脉石英 ,分析其中包裹体分子水与结构羟基水的含量、包裹体分子水的δDinclusion、结构羟基水的δDOH,计算了结构羟基水 包裹体分子水之间的D/H分馏系数αOH inclusion。考查了混合水 (结构羟基水 +包裹体分子水 )δDwhole water与单独包裹体水δDinclusion之间的差别 ,分析了这种差别与分馏系数αOH inclusion的关系。结果表明 :花岗岩样品中两种水之间的分馏系数小 ,分馏程度大 ,在常规分析中 ,若采用测定混合水δDwhole water值代表实际流体 (包裹体水 )δDinclusion值时 ,二者间有较大的差异。热液石英脉样品总体来说分馏系数接近于 1,分馏程度小 ,常规分析中引起的二者之间差异小。常规的分析方法用于分馏程度小的热液脉石英是可行的 ,但进行花岗岩石英水的氢同位素分析时有必要区分出包裹体水与羟基水。     

Amniotic fluid alpha-fetoprotein levels and prenatal diagnosis of autosomal trisomies

Pregnancies with fetal trisomy 21 have been associated with low amniotic fluid alpha-fetoprotein levels (AFAFP). This observation led to the suggestion that low AFAFP levels be used as a criterion for completion of a chromosomal analysis in patients who are not otherwise at increased risk for a fetal chromosome abnormality and in whom karyotyping might not have been completed for economic reasons. In order to assess the usefulness of such criteria, we reviewed the AFAFP levels of 90 cases of fetal trisomy 21, 23 cases of trisomy 18, and 10 cases of trisomy 13. These were compared with 2400 control samples with normal chromosome constitution. AFAFP levels were generally lower in pregnancies with trisomy 21, showing a median value of 0·72 MoM. However, 40 per cent of the trisomy 21 samples had AFAFP values greater than 0·8 MoM and 20 per cent were over 1·0 MoM. These data imply that over 50 per cent of Down syndrome cases might have been missed using a cut-off level of 0·70 MoM for completion of chromosome analysis. Using a higher cut-off level will leave only a small percentage of samples unkaryotyped. The distribution of AFP levels in trisomy 13 and 18 is no different from controls; we therefore believe that fetal karyotyping should be completed in every amniotic fluid sample obtained.     

青海滩间山金矿床地质特征及其铅同位素组成的地质意义

滩间山金矿床产于中元古界蓟县系万洞沟群碳质糜棱片岩和华力西晚期侵入岩中。该金矿床天在热水沉积、区域变质和热变质预富集的基础上，与区域绿片岩相脆韧性剪切变形变质带的退化演化同步，经历了脆韧性、韧脆性和脆性剪切变形成矿阶段的演化，井遭受华力西晚期侵入岩浆活动的叠加改造而形成的。矿区地层、侵入岩、矿石及黄铁矿的铅同位素组成表现出良好的亲缘关系，较清楚地反映了地层和侵入岩浆活动对成矿物质的贡献。     

溢油指示物(指标)HPLC-UVD研究

建立了溢油指示物（ 指标）ＨＰＬＣ—ＵＶＤ 相似性模式，给出了溢油指示物（ 指标）ＨＰＬＣ—ＵＶＤ 相似性的择近原则，指出溢油指示物（ 指标）ＨＰＬＣ—ＵＶＤ相似性主要受控于油种、风化和实验误差等因素的影响。结果表明，ＨＰＬＣ—ＵＶＤ 相似性模式可作为溢油指示物（ 指标） 。     

Initial Homotypic Cell Pair Adhesion in Regenerating Hydra Facilitates Subsequent Adhesion of Homotypic Cells

 In Hydra vulgaris at the level of dissociated single cells endodermal cells adhere to each other more readily than to ectodermal cells at the initial adhesion. The time required for adhesion to occur between two adjacent cells is shorter for both endodermal and ectodermal homotypic cell adhesions once the initial adhesion of the first pair of cells has been established. It is confirmed that contact of an aggregated pair with additional homotypic cells facilitates the occurrence of homotypic adhesions; heterotypic adhesions are discouraged. This suggests that adhesion of homotypic cells contributes to an increased readiness for subsequent homotypic cells to adhere. Received: 25 August 1999 / Accepted in revised form: 11 January 2000     

铝、铁共聚作用的化学特征及晶貌研究

通过对铝，铁水解共聚物的合成制备及其水解共聚合过程电位滴定的研究，并通过扫描电镜对其共聚物样品的晶貌观测，ｎＡｌ／ｎＦｅ的点能谱及结构组成的红外光谱测定，对铝铁共聚作用的化学特征及其晶形貌象，共聚作用进行了研究及讨论，为深入研究铝无机共聚溶液体系化学形态组成及其絮凝剂的提供了的基础实验依据。     

新型高效台车式退火炉研制

退火炉采取小燃烧室,对工件实行侧下加热、强化绝热措施复合炉衬、二次均热风管、扩张室沉降等五项措施.目的是为了提高炉的热效率和炉温的均匀度.在耗煤量较低的情况下能保持较高的燃烧室强度.有利于强化燃烧和减少蓄散热损失.实行扩张室沉降,在不加任何除尘装置的条件下烟尘排放浓度达到了国家标准新规定的排放要求,而且大大改善了工人的劳动条件.     

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.