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571.
Frans J. Los PhD Adriana M. Hagenaars Titia E. Cohen-Overbeek Hendrik W. P. Quartero 《黑龙江环境通报》1994,14(7):565-568
The levels of the maternal serum markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), and unconjugated oestriol (uE3) in 35 pregnant women with early second-trimester oligohydramnios differed from those in a reference population of 1699 singleton pregnancies. Maternal serum AFP levels above the 95th centile of the population distribution were observed in 80 per cent (16/20) of oligohydramnios cases with a normal fetus and in only 20 per cent (3/15) of the cases with a fetus displaying urogenital tract malformations. Elevated levels of hCG (above the 95th centile) and decreased levels of uE3 (below the fifth centile) were encountered in 26 per cent (9/35) and 17 per cent (6/35) of the women, irrespective of the fetal condition. The abnormal profile of the serum markers in early second-trimester oligohydramnios resulted in 57 per cent (20 out of 35) of screen-positive cases for either fetal Down's syndrome or neural tube defects, compared with 8·4 per cent (143 out of 1699) in the reference population. 相似文献
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574.
Accumulation of Hg(II) by microbial biofilms on suspended particulate matter 相似文献
575.
环境保险在中国的可行性探讨 总被引:8,自引:0,他引:8
在解决环境问题的过程中,包含着诸多的商机,环境保险就是其中一例。环境保险属于责任保险的一种,介绍了环境保险在西方发达国家的发展与实践,并结合我国保险业的现状,得出在我国施行环境保险,既是我国保险业自身发展的需要,也是企业规避风险的需要。 相似文献
576.
运用火焰塞曼原子吸收对铁、镍、锰等谱线较复杂的元素进行了测定,在实验的基础上,提出了仪器最佳工作条件,并对该分析方法的灵敏度、精密度及准确度进行了探讨。 相似文献
577.
Changhong Chen Yarong Peng Hongli Wang Qian Wang Shengao Jing Jingyu An Yaqin Gao Cheng Huang Rusha Yan Haixia Dai Tiantao Cheng Qiang Zhang Meng Li Jianlin Hu Zhihao Shi Li Li Shengrong Lou Shikang Tao Qinyao Hu Jun Lu 《环境科学学报(英文版)》2023,35(2):794-805
Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China, in contrast to the fact that an increase in emissions of non-methane hydrocarbons (NMHCs) has been reported. This study employed seven years continuous NMHCs measurements and the related activities data of Shanghai, a megacity in China, to explore evolution of emissions and effectiveness of air pollution control measures. The mixing ratio of NMHCs showed no statistical interannual changes, of which their compositions exhibited marked changes. This resulted in a decreasing trend of ozone formation potential by 3.8%/year (p < 0.05, the same below), which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime. Observed alkanes, aromatics and acetylene changed by +3.7%/year, -5.9%/year and -7.4%/year, respectively, and alkenes showed no apparent trend. NMHCs sources were apportioned by a positive matrix factorization model. Accordingly, vehicular emissions (-5.9%/year) and petrochemical industry emissions (-7.1%/year) decreased significantly, but the decrease slowed down; significant reduction in solvent usage (-9.0%/year) appeared after 2010; however, emissions of natural gas (+12.6%/year) and fuel evaporation (with an increasing fraction) became more important. The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions, emphasizing the need for further validation in NMHCs emission inventory. Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions, which provided new insights into future air policies in polluted region. 相似文献
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579.
Christoph Brezinka Adriana M. Hagenaars Professor Juriy W. Wladimiroff MD PhD Frans J. Los 《黑龙江环境通报》1995,15(8):699-703
Doppler flow velocity waveform recording in the fetal ductus venosus and umbilical artery as well as maternal blood sampling for serum alpha-fetoprotein (MSAFP) was performed before and after transabdominal chorion villus sampling (TACVS) in 36 women of advanced maternal age (≥ 36 years). Gestational age ranged between 11 and 13 weeks. No chromosomal anomaly was detected. No statistically significant difference was observed in ductus venosus velocity parameters or in the umbilical artery pulsatility index (PI) before and after CVS in 35 women with a normal pregnancy outcome. One case resulted in fetal loss. Post-CVS median MSAFP levels at 12 weeks (25 kIU/1) and 13 weeks (35 kIU/1) were significantly higher than pre-CVS levels. In three cases, post-CVS MSAFP levels were higher than 600 kIU/1, correlating with feto-maternal transfusions of approximately 1.0–1.4 ml, i.e., of around 40 per cent of feto-placental blood volume. One of these cases displayed absence of fetal peripheral blood flow velocities and fetal bradycardia following TACVS, resulting in fetal loss 1 week later. The remaining two cases had a normal pregnancy outcome, but showed a more than 50 per cent reduction in ductus venosus velocity after TACVS, whereas umbilical artery PI remained unchanged. However, similar velocity changes were associated with only small feto-maternal transfusions. Umbilical artery PI values remained unchanged. 相似文献
580.