Detection of low-grade mosaicism in fetal cells isolated from maternal blood

Recovering and analysing fetal erythrocytes from maternal blood is being pursued for non-invasive prenatal genetic diagnosis. We report the observation of 46, XY/47, XXY mosaicism in fetal cells from a woman whose first-trimester chorionic villus sampling (CVS) initially showed only 46, XY. Only after exhaustive (500 cells) analysis were four XXY cells found in cultured villi.     

用AutoCAD软件对弯管芯棒进行快速图解设计

介绍了利用AutoCAD软件对管材弯曲工艺中弯管芯棒进行快速图解设计的方法。利用该法可对不同弯曲半径、弯曲角度、壁厚的管材的弯管芯棒进行快速优化设计。利用Auto CAD进行图解法设计的弯管芯棒尺寸准确 ,结构合理 ,加工工艺性好 ,使用寿命长     

浙江安吉地区地质灾害及其防治对策

本文介绍了安吉地区地质灾害的调查概况，对其成因类型，时空分布，与地质环境的关系和防治对策作了探讨，这圣方政府编制地质灾害防治规划具参考意义。     

太湖梅梁湾水体中可见光的衰减、吸收及散射

对太湖梅梁湾沿岸带和敞水区的水体进行了光学特性研究。结果发现，沿岸带的水下光辐射衰减系数(Kd)值较敞水区小；400nm与500nm向上辐照度比值(Eu440／Eu550),沿岸带在1m左右最小,敞水区在0．5m左右最小;沿岸带的水面下向上辐照度与向下辐照度的比值(R)低于敞水区：440、550、670nm的后向散射与吸收的比值(b／a),在沿岸带的1m处最大,敞水区在0．5m处最大。这些结果说明,相对于敞水区而言,沿岸带的光衰减较弱,无机悬浮颗粒的含量较少,最大叶绿素a分布较深。     

利用EXCEL求算水中非离子氨

Excel是办公自动化中非常重要的一款软件，它的数据处理功能在现有的文字处理软件中可以说是独占螯头，通过简单的学习，结合国家标准给出的换算公式，利用EXCEL编制程序，方便快捷地计算水中非离子氨浓度，计算结果表明，当实际测得水温和pH与表中数据吻合时三种计算方法结果无明显差异，当实际测得的水温和pH与表中不对应时，查表法存在明显偏差，而使用EXCEL运算就能与笔算结果一致，准确可靠。     

云南生物多样性的保护和可持续利用

通过对云南省生物多样性概貌、生物资源特点及生物多样性受到威胁现状和原因的分析，探讨了生物多样性保护模式和对策，以实现生物多样性的持续利用。     

灰色生长曲线与万元产值废水量预测

基于ＧＩＭ（１）灰色线性幂函数曲线，研究开发出ＧＰＭ（１）这一新的灰色生长曲线，并建立了ＧＰＭ（１）简捷的参数辨别方法。研究表明，ＧＰＭ（１）概念明确，结论可信，精度令人满意，比传统的皮尔生长曲线在应用上有着更大的优越性。为具有生长规律的非线性灰色环境系统的分析、预测和决策提供了新途径。     

Flow sorting of fetal erythroblasts using intracytoplasmic anti-fetal haemoglobin: Preliminary observations on maternal samples

Monoclonal antibody to fetal haemoglobin (a₂γy₂) has been proposed as a fetal-specific reagent. We developed an intracellular staining protocol that combines fluorescein isothiocyanate or phycoerythrin conjugated anti-γ with the DNA binding dye Hoechst 33342 to identify and flow sort fetal erythroblasts from maternal blood. Our preliminary observations on anti-γ-positive cells sorted from four different pregnant women are described here, using fluorescence in situ hybridization (FISH) with chromosome-specific probes to identify fetal cells. Our data demonstrate that far fewer candidate fetal cells are sorted with this protocol than by current cell surface staining methods that employ the monoclonal antibody CD71. This results in increased fetal cell sorting purities. With this protocol, standard FISH techniques require modification due to the rigorous fixation with 4 per cent paraformaldehyde. Our initial data indicate the promise of this approach.     

Use of the chemical cleavage of mismatch method for prenatal deficiency diagnosis of alpha-1-antitrypsin

The most common mutation in alpha-1-antitrypsin deficiency, conversion of a G to an A at base 9989 (PI-Z), was detected with the chemical cleavage of mismatch method, demonstrating the power of the method for prenatal diagnosis. Exon V of the gene was amplified using the polymerase chain reaction and heteroduplexes were formed to test for the presence of the mutation. The predicted C mismatch was readily detectable with hydroxylamine, and by making the probe from the chorionic villus sample it was possible to determine that the fetus was heterozygous, not homozygous, for the mutation.     

论民国时期河南灾荒的社会成因

民国年间河南灾荒现象异常突出，虽与当时整体气候背景及河南特殊的地理特征相关，但灾荒背后的社会原因更应引起我们的关注。其主要表现为：一、社会经济乏力，百姓抗灾能力低；二、政治腐败，体现在政府的赋税名目繁多、政府官员失职渎职以及挪用、贪污河防公款等几个方面；三、战争与灾荒；四、帝国主义列强对中国的残酷掠夺。