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121.
The polymorphism of the human serum paraoxonase1 was analyzed by two distinguished methods in six different ethnic groups (Caucasians, Mongoloids, Negroids), using (1) the Computer Method2 and (2) the Carro‐Ciampi Method3‘4. Analysis of the response of the enzyme activities to salts resulting in low and high activity ratios. Comparison of the results: In Caucasians we distinguished three phenotypes by the Computer method. The polymorphism was governed by two alleles. The Hardy‐Weinberg rule for a two‐allele model was valid. Individuals belonging to the homozygotic group with low activity had a low activity ratio (Carro‐Ciampi method). With both methods a frequency between 57% and 61% was observed for this group. Individuals with medium and high activity had a high activity ratio. In Negroids and Mongoloids samples we found (by the Computer method) a low activity group (Ghanaians 9.6%, Jamaicans 13.6%, Indonesians 6.7%, Koreans 19.6%). The Hardy‐Weinberg rule for a two‐ or three‐allele model was not valid. Individuals belonging to the low activity group had a low activity ratio, all individuals with higher activity a high activity ratio (Carro‐Ciampi method). Our results suggest that the members of the low activity group in the three races are homozygote for an identical allele. 相似文献
122.
以国内外文献及标准方法为基础,优化了血清中17种2、3、7、8位取代的PCDD/Fs的测定方法,建立了同位素内标稀释-索式萃取一段法层析柱净化-高分辨气质联用分析方法.实验结果表明,17种2、3、7、8位取代的PCDD/Fs的方法检出限范围为3.72—14.74 pg.基质加标实验中目标化合物回收率为94.61%—117.14%,标准参考物质SRM1958中PCDD/Fs的多数单体测定结果也在参考值范围内.实际样品同位素内标回收率为66.2%—95.2%,RSD是4.0%—9.0%.该分析方法准确可靠、灵敏、操作简便,适用于血清中二噁英的测定. 相似文献
123.
刁江水体多相介质中As,Zn和Pb的空间和季 总被引:5,自引:0,他引:5
调查了广西刁江河水中As,Zn和Pb的溶解态、悬浮颗粒态分布情况及季节变化,以及3种重金属在不同粒级沉积物中的分布情况. 结果表明:刁江流域河水与沉积物中3种重金属污染在流域尺度上的分布存在差异,沉积物污染更为严重. 与土壤污染一致,沉积物中3种重金属的污染范围扩散延伸到距离污染源近200 km的下游区域,其中车河矿区对As污染的贡献率明显高于大厂矿区,而对Pb污染的贡献率明显小于大厂矿区;不同重金属在水体中的赋存形态存在差异,河水中悬浮颗粒态Pb所占比例远高于As和Zn,这与3种重金属矿物的稳定性以及在不同粒级沉积物中的富集特征有关;河水中重金属的赋存形态存在季节差别,丰水期悬浮颗粒态重金属所占比例明显高于枯水期. 相似文献
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125.
《International Journal of Sustainable Engineering》2013,6(2):132-141
Following a brief introduction about the need for businesses to respond to climate change, this paper considers the development of the phrase ‘carbon footprint’. Widely used definitions are considered before the authors offer their own interpretation of how the term should be used. The paper focuses on the contribution small and medium sized enterprises (SMEs) make to the economy and their level of influence in stimulating change within organisations. The experience of an outreach team from the Engineering Department of a UK university is used which draws on the experience of delivering regional economic growth projects funded principally through the European Regional Development Fund. Case studies are used including the development of bespoke carbon footprints for SMEs from an initiative delivered by the outreach team. Limitations of current carbon footprints are identified based on this higher education‐industry knowledge exchange mechanism around three main themes of scope, the assessment method and conversion factors. Evidence and discussions are presented that conclude with the presentation of some solutions based on the work undertaken with SMEs and a discussion on the merits of the two principally used methodologies: life‐cycle analysis and economic input–output assessment. 相似文献
126.
Marcela González Cristina Dapeña Bibiana Cerne Odon Sánchez-Ccoyllo Saulo Freitas Pedro L. Silva Dias Héctor Panarello 《Environmental Fluid Mechanics》2009,9(4):409-425
The SALLJEX experiment was held during the summer 2002–2003. It consisted of three-dimensional observation of the atmosphere
to study the structure of the low level jet along the eastern slopes of the Andes. Daily precipitation water samples were
collected at two stations (Resistencia and Salta) in northern Argentina and isotope content was analyzed. The isotope data
were used in conjunction with air parcel trajectories obtained from a 3-D kinematic model (3D-MTC) developed by the University
of Sao Paulo, Brazil. Values of deuterium excess were related with air masses of continental origin, whilst low values were
associated with air masses with longer oceanic trajectories. Furthermore, although data are scarce, results show that oxygen-18
and deuterium excess in rainwater are related with the occurrence of the low level jet. 相似文献
127.
吸入性甲醛如何将其遗传毒性从呼吸器官经血液转移全身?这是揭示"甲醛致白血病"这个科学问题的关键.以新生牛血清(NBS)为"模拟血液",以Hela细胞为实验材料,采用体外甲醛染毒实验,研究了培养基血清对细胞内硫醇浓度,以及对甲醛诱导性DNA-蛋白质交联(DPC)的影响.结果表明,当培养基中未添加血清时,250μmol·L-1甲醛仅引起较低水平的交联效应,同时细胞内硫醇浓度水平也较低;而加入1%和10%新生牛血清以后,甲醛诱导的DPC均显著上升(p<0.01,p<0.05),同时细胞内硫醇浓度水平也显著上升(p<0.05,p<0.01).培养基中新生牛血清能够再生Hela细胞内的硫醇,同时促进细胞DPC的形成.这可能为理解甲醛远距离毒性,解释吸入甲醛是否能导致白血病提供了基础. 相似文献
128.
从保护臭氧层,保护环境的角度出发,介绍了氯氟烃化合物对环境的影响。阐述了用制冷剂R22代替R502在低蒸发温度应用时需要解决的问题和如何解决。 相似文献
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130.