Glucuronidation of hydroxylated polybrominated diphenyl ethers and their modulation of estrogen UDP-glucuronosyltransferases

Polybrominated diphenyl ethers (PBDEs) can be metabolically converted to their hydroxylated metabolites (OH-PBDEs). The estrogenic effects of PBDEs may be mediated by OH-PBDEs, but the mechanisms of which are still not understood. This study investigated the glucuronidation of 11 OH-PBDEs and their potential in modulating UDP-glucuronosyltransferases (UGTs) activity of 17β-estradiol (E2) in rat liver microsomes. The number of bromine atoms at phenolic ring was observed as the most influential factor of OH-PBDEs glucuronidation. 2′-OH-BDE-28 having one bromine atom at phenolic ring showed the fastest metabolic rates with t_1/2 value of 3.86 min, while 6-OH-BDE-137 having four bromine atoms at phenolic ring was the poorest substrate with t_1/2 value over 60 min. Regarding to the modulation of E2-UGTs activity, the phenolic hydroxyl group in OH-PBDEs played an essential role. Depending on the substitution patterns of bromine and hydroxyl group, OH-PBDEs inhibited or stimulated E2-UGTs activity. Ten of OH-PBDEs inhibited both 3-glucuronidation and 17-glucuronidation of E2 with IC₅₀ values varying from 3.80 to 129.38 μM, while 3′-OH-BDE-100 exhibited stimulating effects on 3-glucuronidation with EC₅₀ value of 35.95 μM. Kinetic analysis suggested noncompetitive inhibition mode of E2 glucuronidation by 3′-OH-BDE-7, 6-OH-BDE-47 and 2′-OH-BDE-68 with K_i values varying from 11.95 to 67.22 μM. This study demonstrated OH-PBDEs exhibited large interindividual differences in glucuronidation and modulation of E2-UGTs activity. By inhibiting the formation of E2 glucuronidation, OH-PBDEs may increase E2 bioavailability in target tissue, thereby exerting an indirect estrogenic effect.     

硬岩金属矿山开采活动与矿山地震活动的关系研究

以冬瓜山微震监测的数据为基础,结合开采、地质条件等因素,运用统计学和线形拟合方法,研究了开采活动与矿山地震活动的关系特征。其结果发现:累积矿震事件数与累积采掘体积、爆破药量存在着双对数线性的正比例关系;而累积矿震能量却与开采体积存在着斜率为负的双对数线性关系;较大矿震事件主要发生在开采爆破活动之后的时间内,震级大于0的矿震事件在时间上要超前爆破事件,矿震活动在开采活动之后呈现从强到弱再从弱到强的变化过程。该结果对硬岩金属矿山的矿震活动研究有一定的参考价值。     

区域社会经济发展与生态环境耦合关系研究模型的比较分析

社会经济发展与环境资源相协调是可持续发展的重要途径,判断当前区域社会经济发展与生态环境间的耦合关系是建立有效协调机制的关键。本文从发展、机理方法和应用实例等方面系统介绍了目前在社会经济发展与生态环境之间耦合关系研究中主要的3类模型:计量经济学模型(环境库兹涅茨曲线)、耦合度定量判断模型(包括灰色关联度分析和数理模型)和系统动力学模型。通过3类模型机理和应用情况的对照分析,总结各自优劣势,并认为具有多情景分析和多方案执行评估能力的神经网络模型将成为未来发展趋势。     

Community analysis of ammonia and nitrite oxidizers in start-up of aerobic granular sludge reactor

A lab-scale sequencing batch reactor (SBR) was setup and the aerobic granular sludge was successfully incubated by using anaerobic granular sludge as seed sludge. Nitrogen was partially removed by simultaneous nitrification and denitrification (SND) via nitrite with free ammonia (FA) of about 10 mg/L. The denaturing gradient gel electrophoresis (DGGE) method was used to investigate community structure of α-Proteobacteria, β-Proteobacteria, ammonia oxidizing bacteria (AOB), and Nitrospira populations during start-up. The population sizes of bacteria, AOB and Nitrospira were examined using real-time PCR method. The analysis of community structure and Shannon index showed that stable structure of AOB population was obtained at the day 35, while the communities of α-Proteobacteria, β-Proteobacteria, and Nitrospira became stable after day 45. At stable stage, the average cell densities were 1.1×1012, 2.2×1010 and 1.0×1010 cells/L for bacteria, AOB and Nitrospira, respectively. The relationship between characteristics of nitrifying bacteria community and nitrogenous substrate utilization constant was discussed by calculating Pearson correlation. Certain correlation seemed to exist between population size, biodiversity, and degradation constant. And the influence of population size might be greater than that of biodiversity.     

红壤丘岗坡地土地利用与土壤水分的时空变化关系

利用连续2a土壤水分定位观测数据,对红壤丘岗坡地不同土地利用类型与土壤水分时空关系的研究结果表明：（1）生长季（3—10月）不同土地利用类型之间0—90cm深土壤平均含水量差异显著,丰水年的差异比平水年大。（2）不同水文年同一土地利用类型土壤水分季节变化差异明显。丰水年土壤水分含量较高,年内变化较平稳,土壤基本处于湿润状态;而平水年土壤水分先升高后显著降低再缓慢升高,出现明显的干湿交替。（3）从丰水年到平水年土壤水分的剖面结构类型没有发生改变,湿地松区属波动型,其他4种土地利用类型属增长型。（4）土壤水分沿坡位的年内变化始终是坡上大于坡下,持续干旱能减少土壤水分沿坡位分布的变化幅度。     

基于QSPR方法的烃类物质苯胺点预测

烃类物质在石油工业中有着非常广泛的应用.在石油工业中常用苯胺点来衡量有机溶剂的溶解性能.基于定量结构-性质相关性(QSPR)原理,根据分子结构计算反映分子结构信息的结构参数,应用遗传函数算法从大量结构参数中优化筛选出与烃类物质苯胺点最为密切相关的结构参数作为表征相应化合物结构特征的分子描述符,采用多元线性回归方法对分子描述符与苯胺点之间的定量函数关系进行关联,建立了预测烃类物质苯胺点的理论模型.最后,对模型进行了内部及外部验证来检验模型的可靠性.在此基础上,对所建立的预测模型进行机理解释,分析了影响烃类物质苯胺点的主要结构因素及其影响规律.研究表明,所建模型具有较高的稳定性和预测能力.     

不同土壤中Zn有效态含量与全量关系的统计研究

以"全国重点区域土壤环境质量数据库"为数据源,依据pH值、有机质含量、阳离子交换量筛选出时间、空间分布不连续的3组402个土壤样品,对土壤中Zn有效态含量与全量的相关性进行了统计分析.结果表明,在pH值5.0～6.5、有机质含量1.0%～2.5%,pH值5.0～6.5、有机质含量2.5%～4.0%,pH值7.5～8.5、有机质含量1%～2.5%等3类土壤条件下(阳离子交换量均介于15～30cmol·kg-1),土壤中的Zn有效态含量与全量之间均存在显著的相关性,且均能在Zn有效态含量与全量之间建立起有意义的回归方程.     

应用线性自由能关系估算药用活性化合物的生物碳质-水吸附系数

线性自由能关系(LFER)可以用来预测生物碳质对水中药用活性化合物(Ph ACs)的吸附系数,并确定不同分子间作用力对生物碳质吸附性能的相对贡献.利用商业水稻秸秆生物碳质(碳化温度400~500℃,200目)与14种带有不同表面官能团的Ph ACs(羧酸类、羟基类、氮杂环类)进行了吸附等温实验.各物质的等温吸附实验数据均可用Freundlich方程进行很好地拟合.通过建立的LFER模型,可以预测吸附质任一化学饱和水平(CW/SW)下的lg Kd,activity.利用复相关系数(R2=0.93)、回归系数标准偏差(SE=0.23)、F统计量(268)、去一法交叉验证系数(Q2LOO=0.90)以及外部样本交叉验证相关系数(Q2EXT=0.92)等方法对该模型进行验证,结果表明,其显著性与稳健性较好,具有预测能力.模型结果表明在低浓度范围内,空穴作用(V)与氢键碱作用(B)在整个吸附过程中起到主导作用,其中空穴作用为正贡献,氢键碱作用为负贡献.     

典型岛礁大气环境室内加速腐蚀试验谱研究

目的研究装备典型岛礁大气环境的室内加速腐蚀试验方法。方法采用灰色关联分析法得到引起武器装备腐蚀损伤的主要环境因素,通过分析装备服役面临的岛礁腐蚀环境数据,编制出岛礁大气环境谱。依据当量腐蚀加速原理及测定的腐蚀当量折算系数,建立加速腐蚀试验条件与岛礁大气环境谱之间的等效转换关系。结果归纳出室内加速腐蚀试验谱的编制方法,得到面向装备服役岛礁大气环境的室内加速腐蚀试验谱。结论确定的室内加速腐蚀试验谱及加速关系,为地(舰)面武器装备选材及结构腐蚀寿命评定提供了重要依据。     

Spatial pattern of impervious surfaces and their impacts on land surface temperature in Beijing, China

Land surface temperature （LST）, which is heavily influenced by urban surface structures, is a significant parameter in urban environmental analysis. This study examined the effect impervious surfaces （IS） spatial patterns have on LST in Beijing, China. A classification and regression tree model （CART） was adopted to estimate IS as a continuous variable using Landsat images from two seasons combined with QuickBird. LST was retrieved from the Landsat Thematic Mapper （TM） image to examine the relationships between IS and LST. The results revealed that CART was capable of consistently predicting LST with acceptable accuracy （correlation coefficient of 0.94 and the average error of 8.59%）. Spatial patterns of IS exhibited changing gradients across the various urban-rural transects, with LST values showing a concentric shape that increased as you moved from the outskirts towards the downtown areas. Transect analysis also indicated that the changes in both IS and LST patterns were similar at various resolution levels, which suggests a distinct linear relationship between them. Results of correlation analysis further showed that IS tended to be positively correlated with LST, and that the correlation coefficients increased from 0.807 to 0.925 with increases in IS pixel size. The findings identified in this study provide a theoretical basis for improving urban planning efforts to lessen urban temperatures and thus dampen urban heat island effects.