内蒙古农牧交错带土地利用变化对CH4吸收的影响

于2008~2010年,根据邻近样地采样原则,选择位于内蒙古农牧交错带的天然草地和不同开垦时间的农田作为研究样地(G-草地; C5-开垦5a的农田;C10-开垦10a的农田;和C50-开垦50a的农田),利用静态箱法通过3a的野外试验,研究土地利用类型变化对CH4吸收的影响.结果表明:天然草地转变为农田后,不同开垦年限的农田土壤和草地土壤CH4吸收存在显著差异2008年(FCH4=273.7, P<0.001), 2009年(FCH4=264.8, P<0.001)和2010年(FCH4=362.4, P<0.001).草地转变为农田促进CH4吸收,2008, 2009 和2010年生长季的生长季(4~10月),草地CH4吸收量最低分别为141.4,210.0,236.0mg/m2.2008~2010年农田土壤CH4累积吸收量与草地土壤相比增加20%~280%.农田开垦年限影响CH4吸收,随着农田开垦年限的增加从开垦5~50a,CH4累积吸收量降低.相关分析表明,不同土壤CH4吸收与土壤水分含量和NH4+-N 含量呈负相关关系(R2=0.7380, P<0.01).草地转变为农田后,土壤水分含量和NH4+-N 含量驱动不同开垦年限的农田土壤和草地土壤CH4吸收差异.     

跨域生态治理“碎片化”的限度审视与整体性治理机制研究

突破行政区划,构建跨域生态治理的有效实践机制是推进生态文明、建设美丽中国的迫切需要。数字技术建构了全新的治理场域,也形塑着新的治理模式。本文将跨域生态治理置于数字化时代的宏大视野,研究认为：传统跨域生态治理模式面临难以突破的“碎片化”瓶颈,主要表现为治理目标碎片化、治理资源碎片化和治理主体碎片化,究其原因在于利益失衡下的府际不合,“技”“智”缺位下的整合失力和能力动力双匮下的参与缺失。基于此,在系统解构整体性治理理论内涵的基础上,数字化时代跨域生态治理与整体性治理在价值、工具和场域方面存在高度耦合。最后,提出通过科学补偿和考核优化建立利益共享机制,通过资源整合与整体智治建立科学施策机制、信息共享与诉求回应建立多元协同机制,形塑整体性治理的协调、整合、信任机制,以期推进“碎片化”问题的弥合解决和跨域生态治理现代化的实现。     

空气幕技术在阻断矿井漏风中的应用

在通风系统改造过程中,应用“有效压力理论”充分利用闲置设备,自行设计制造了节能空气幕,既节省了空气幕的成品购置费用,又解决了系统的漏风问题。     

大鼠不同脏器亚硫酸氧化酶活性及其与年龄的关系

为了探讨体内亚硫酸氧化酶的分布特点及随年龄的变化规律,以Wistar大鼠为实验材料,研究了不同月龄大鼠脏器中的亚硫酸氧化酶活性.以细胞色素C为电子受体,应用分光光度法测定了不同月龄(1、4、10个月)大鼠肝、肾、肺、脾、脑、胃及胸主动脉中亚硫酸氧化酶的活性.结果表明:1)亚硫酸氧化酶在大鼠全身主要脏器中普遍存在,且在不同脏器中该酶的活性不同,从强到弱的顺序基本表现为:肝、肾>胃>脑>胸主动脉血管>肺>脾;2)肝、肾、血管组织中亚硫酸氧化酶活性与大鼠年龄相关,肝脏亚硫酸氧化酶活性随年龄的增加而增加(Spearman,r=0.674,p<0.001),而肾脏和胸主动脉血管该酶活性随年龄的增加而减小(Spearman,r=-0.756,p<0.001;r=-0.629;p<0.05),其余脏器未见明显变化;3)亚硫酸氧化酶活性降低可能是一种机体衰老的生化标志物.     

曝气池容积计算方法分析

文中对曝气池容积的计算方法———BOD5污泥负荷率法与污泥龄法进行了分析。这两种方法实质上是属于同一个公式 ,只是考虑的角度不同而引入的两个不同概念。如能将考虑的角度有机地结合 ,将使曝气池容积的设计计算更趋合理。     

性腺发育及年龄对养殖中华鲟抗氧化力的影响

以养殖的子一代（n=21）中华鲟为对象,研究了性腺发育及年龄对其抗氧化力的影响。结果表明：（1）1998年生子一代雌性(未达性成熟,性腺处于慢速发育阶段)和雄性(接近性成熟,性腺处于开始快速发育阶段)的睾酮和雌二醇/睾酮差异显著,雌性血清丙二醛水平显著低于雄性,而超氧化物歧化酶和谷胱甘肽过氧化酶的活力及超氧化物歧化酶/丙二醛值虽高于雄性,但二者间不存在显著性差异,雌性和雄性的丙二醛与超氧化物歧化酶/丙二醛之间相关性极显著（r=-0915,-0818,P＜001);（2）雌二醇/睾酮值与丙二醛显著负相关,与超氧化物歧化酶/丙二醛显著正相关（r=-0635,r=0709,P＜005）,与超氧化物歧化酶、谷胱甘肽过氧化酶无显著相关性;（3）4个年龄组（4、8、11、12龄,未达性成熟）的超氧化物歧化酶和丙二醛无显著性差异,12龄组的谷胱甘肽过氧化酶显著低于其余3组,而超氧化物歧化酶/丙二醛显著高于其余3组,谷胱甘肽过氧化酶和丙二醛与年龄呈负相关（r=-0547,P＜001;r=-0519,P＜005）,超氧化物歧化酶/丙二醛与年龄呈正相关（r=0569,P＜001）。这表明进入性腺快速发育阶段的雄性氧化应激水平明显高于处于性腺慢速发育阶段的同龄雌性;随着年龄增长,未达性成熟中华鲟的抗氧化力水平逐渐增强;使用以上指标作为亚健康群体的筛选指标和氧化应激的生物标志物时,应充分考虑监测群体性腺发育和年龄因素,以使参考指标更准确     

Maternal exposure to high levels of dioxins in relation to birth weight in women affected by Yusho disease

Background

Studies on the association of maternal exposure to polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) with decreased birth weight in humans have produced conflicting results. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease.

Objective

The Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on birth weight.

Methods

Blood samples, obtained from 101 Yusho women (190 births) who gave birth after exposure, were analyzed for congeners of seven PCDDs, ten PCDFs, and four non-ortho PCBs.

Results

Total PCDD TEQ (adjusted beta = − 161.9 g; 95% CI, −265.3 to − 58.6), total PCDF TEQ (adjusted beta = − 105.9 g; 95% CI, −179.5 to − 32.2), and total non-ortho PCBs (adjusted beta = − 178.4 g; 95% CI, −318.3 to − 38.5) levels were inversely associated with birth weight. Significant inverse associations with birth weight were also found for total PCDD TEQ, total PCDF TEQ, and total non-ortho PCB TEQ levels among male, but not female, infants. Significant inverse associations with birth weight were also found for nine congeners among all infants; the adjusted beta coefficients were largest for 1,2,3,6,7,8-HxCDD and smallest for 2,3,4,7,8-PeCDF.

Conclusion

In the setting of exposure to high levels of dioxins, maternal blood levels of PCDDs, PCDFs and PCBs are associated with lower birth weight in Yusho patients. The association exhibited gender-specific differences, as male infants are more susceptible than females to growth restriction induced by in utero dioxin exposures.     

Comparison of the concentrations of polychlorinated biphenyls and dioxins in mothers affected by the Yusho incident and their children

Accumulated maternal dioxins are passed onto the fetus and neonate via the placenta and maternal milk. In Japan in 1968, an accidental human exposure to rice oil contaminated with polychlorinated biphenyls (PCBs) and other dioxin-related compounds, such as polychlorinated dibenzofurans (PCDFs), led to development of Yusho oil disease. We investigated differences in blood dioxin concentrations in mother-children pairs affected by the Yusho incident. From 2002 to 2008, blood samples were collected from 26 pairs of Yusho mothers and their children (19 mothers, 26 children). Specific congeners of seven polychlorinated dibenzo-p-dioxins (PCDDs), ten PCDFs, and four non-ortho PCBs were analyzed. The children had significantly lower TEQ concentrations of PCDDs, PCDFs, and coplanar PCBs compared to their mothers. The mother-child difference in blood concentrations varied with the congeners; the largest for 2,3,4,7,8-pentaCDF and the smallest for 1,2,3,4,6,7,8-heptaCDD. The level for 2,3,4,7,8-pentaCDF, which characterizes Yusho oil disease, was approximately 17-30 times higher in the mothers than in the general population, whereas there were no significant differences between children in the formula-fed group and the general population. In contrast, the mean level for 2,3,4,7,8-pentaCDF in the breast-fed group was approximately 1.5 times, (range 0.5-6.5 times) higher than that in the general population. Over 30 years after the Yusho incident, the mean blood dioxin levels in the offspring were only a fraction of the levels in their mothers. This is more consistent with exposure via breast milk than via transplacental transfer in the Yusho incident.     

Bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers in wild frogs

To investigate bioaccumulation, maternal transfer and elimination of polybrominated diphenyl ethers (PBDEs) in amphibians, we collected adult frogs (Rana limnocharis) from a rice field in an e-waste recycling site in China. We found that ∑PBDEs in the whole frogs and various tissues (brain, liver, testis and egg) ranged from 17.10 to 141.11 ng g⁻¹ wet weight. Various tissues exhibited a similar PBDE congener profile, which was characterized by intermediate brominated congeners (BDE-99 and BDE-153) as the largest contributors, with less lower brominated congeners (BDE-28 and BDE-47) and higher brominated congeners (BDE-209). The maternal transfer capacity of PBDEs declined with the increase in bromine numbers of PBDE congeners. We suggest that the bromine atom number (the molecular size, to some degree) might be a determining factor for the maternal transport of a PBDE congener rather than K_ow (Octanol-Water partition coefficient), which expresses a compound’s lipophilicity. ∑PBDEs concentrations in frogs decreased over time during a depuration period of 54 days when these wild frogs were brought to the lab from the e-waste recycling site. The half-life of ∑PBDEs was 35 days, with about 14 days for BDE-47, and 36 and 81 days for BDE-99 and BDE-153, respectively. The data shows that the elimination of PBDEs has no essential difference from aquatic and terrestrial species.