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271.
272.
Kevin Spencer Adolfo W. Liao Charas Y. T. Ong Lut Geerts Kypros H. Nicolaides 《黑龙江环境通报》2001,21(6):441-444
Dimeric inhibin A was measured in maternal serum samples from 45 pregnancies affected by trisomy 21 and 493 samples from unaffected pregnancies at 10–14 weeks of gestation. Inhibin A levels in affected pregnancies were compared with levels of free β-hCG and PAPP-A in the same series. In the trisomy 21 group, the median multiple of the median (MoM) inhibin A was not significantly elevated (1.28 vs 1.00) with only 15.5% being above the 95th centile. In contrast, the median MoM free β-hCG was significantly increased (2.05 vs 1.00) with 36% above the 95th centile and PAPP-A was significantly reduced (0.49 vs 1.00) with 42% below the 5th centile. Inhibin A levels in the trisomy 21 group were significantly correlated with gestational age such that median levels rose from 1.04 at 11 weeks to 1.30 at 12 weeks and 1.67 at 13 weeks. These findings suggest that first trimester biochemical screening for trisomy 21, which is currently optimised using maternal serum free β-hCG and PAPP-A and fetal nuchal translucency, will not benefit from the inclusion of inhibin A. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
273.
本文分析了环境隐患与安全隐患的异同,定义了冶金矿业行业环境隐患的含义,分析了环境隐患与环境事故的关系,提出环境隐患因子识别的原则、范围和方法。根据冶金矿业行业实际生产情况,用LEC法和危险物质辨识方法对冶金矿业环境隐患进行识别,最终指出常见的冶金矿业环境隐患因子。 相似文献
274.
A highly active ZrOx/ZnO catalyst for microwave-assisted photocatalytic (MW/PC) degradation of endocrine disruptor dimethyl
phthalate (DMP) has been prepared via cetyltrimethylammonium assisted hydrothermal method. The ZrOx/ZnO was characterized by
XPS, XRD, UV-Vis, BET and SEM techniques. The XPS result showed that Zr oxides with different valences (+2, +3, +4) co-existed
in ZrOx/ZnO. By using the ZrOx/ZnO (0.1 g), the TOC removal efficiency of DMP (100 mL of 50 mg/L) was 88% after 30 min reaction,
which was about 15% higher than P25 TiO2. It was found that the removal process of DMP by MW/PC followed pseudo first-order
kinetics in all cases, and ZrOx/ZnO significantly accelerated the degradation of DMP. The degradation half-life time of DMP was
shortened 45% compared with P25 TiO2. A possible catalytic mechanism was proposed based on microwave response and interfacial
charge transfer. ZrOx/ZnO could be reused for six times without obvious decrease in catalytic activity. The study offers new insights
into designing highly efficient catalysts for MW/PC process and is applicable for MW/PC environmental remediation. 相似文献
275.
The novel carbon dioxide(CO2) adsorbents with a high capture effciency were prepared through impregnating the as-synthesized MCM-41 with three kinds of amines,namely diethylenetriamine(DETA) ,triethylenetetramine(TETA) and 2-amino-2-methyl-1-propanol(AMP) .The resultant samples were characterized by small angle X-ray diffraction and low temperature N2 adsorption.The synthesis way not only saves the energy or extractor to remove the template but also is environmentally friendly due to the absence of the potential pollutants such as toluene.CO2 capture was investigated in a dynamic packed column.The sample impregnated by TETA showed the highest adsorption capacity,approximately 2.22 mmol/g at 60°C due to its highest amino-groups content among the three amines.The CO2 adsorption behavior was also investigated with the deactivation model,which showed an excellent prediction for the breakthrough curves. 相似文献
276.
从保障再生水微生物安全的角度,考察了北方某污水处理厂污水处理工艺、混凝沉淀过滤工艺以及臭氧消毒对大肠杆菌和总细菌的去除效果。结果表明,污水处理厂进水中大肠杆菌数和细菌总数分别为10^5-10^9个/L和10^9-10^11个/L,经过厌氧-缺氧-好氧组合工艺处理后两者分别降为10^3-10^6个/L和10^6-10^9个/L,再经后续混凝沉淀过滤工艺(混凝剂PAC投加量:15 mg/L Al2O3)处理,再生水中大肠杆菌和细菌总数仍分别高达10^2-10^5个/L和10^5-10^8个/L。对上述再生水进行臭氧消毒批量实验,在臭氧反应量为12 mg/L的条件下实现了对大肠杆菌的完全灭活,此时臭氧消毒运行费用为0.13元/m^3左右。 相似文献
277.
针对川渝管网分布特点,提出了适于维抢修单点、多点分布的中心、内环最优布局方式,并给出了最优路径算法,这将有效地缩短维抢修响应时间,提高抢修效率. 相似文献
278.
279.
Exploring uncertainty of the change from ICD-9 to ICD-10 on acute mortality effects of air pollution
Qian Z He Q Lin HM Kong L Liao D Gong J Bentley CM Wei H 《Environment international》2008,34(2):248-253
The change in ICD coding from ICD-9 to ICD-10 may produce inconsistencies and discontinuities in cause-specific mortality, thus impacting on effects estimates of air pollution on mortality. The current study was conducted in Wuhan, China. We examined the concordant rates and Kappa statistics using the mortality data from the year 2002 coded with both ICD-9 and ICD-10 codes and compared the estimated effects of air pollution using the Generalized Additive Model in R. We found high concordant rates (>99.3%) and Kappa statistics close to 1.0 (>0.98). Little difference was identified in the estimated effects of air pollution on daily cardiovascular, stroke, cardiac, cardiopulmonary, and respiratory mortality. This study provides evidence that, based on the wide definitions of cause-specific morality typically used in the studies of time-series air pollution mortality, the change in the ICD coding does not significantly affect the estimated effects of air pollution. 相似文献
280.
A TiO2 thin film electrode deposited on porous nickel net (TiO2/Ni) was prepared by the sol-gel method, and the surface morphology, crystal structure features and the grain size were characterized by Field emission scan electron microscopy (FESEM) and X-ray diffraction (XRD). The photoelectrocatalytic system was set up using a UV high-pressure mercury lamp as the light source, TiO2 coated on foamed nickel as photo anode, Pt sheet as counter electrode and the pesticide dipterex in synthetic wastewater. Various factors that influence the photoelectrocatalytic decomposition of dipterex pesticide have been studied, such as degradation time, the type of electrolyte, current density, original pH value and different degradation methods. The prepared catalysts were employed to photoelectrocatalytically degrade the pesticide dipterex under UV irradiation, comparing the results with photocatalytic degradation and electrochemical oxidation. The results indicated that under the optimal conditions of 0.02 mol/L NaCl as the supporting electrolyte, current density = 2.5 mA/cm2, pH 6.0 and dipterex pesticide 40 mg/L, and reaction time 2 hr, dipterex chemical oxygen demand (COD) removal rate and organophosphorous conversion of up to 82.6% and 83.5% were achieved, respectively. The method of photoelectrocatalytic degradation is more efficient than photocatalysis and electrochemical oxidation. The possible roles of the electrolytes on the reactions and probable mechanisms were also discussed. 相似文献