基于C5.0决策树和时序HJ-1A/B CCD数据的神农架林区植被分类

我国神农架林区海拔高、气候复杂,森林类型多样,结构破碎,森林遥感分类难度较大。将2013年时间序列HJ-1A/B CCD遥感影像作为数据源,计算出植被指数(NDVI、DVI、RVI)和主成分第一分量(PC1),使用DEM数据生成地形因子(高程、坡度、坡向),构建植被分类时序因子集。运用C5.0决策树分类法将神农架林区植被细分为七类:针叶林;针阔混交林;落叶阔叶林;常绿和落叶阔叶混交林;常绿阔叶林;灌丛和草甸。结果表明:该方法的总体精度为72.7%,Kappa系数为0.67;在6~8月,针叶林、草甸和灌丛的植被指数明显低于常绿阔叶林、常绿和落叶阔叶混交林、落叶阔叶林和针阔混交林,对分类的贡献较大,称为植被分类的"窗口期"。PC1、NDVI和高程因子对神农架林地的区分度较高,而坡度、坡向和RVI因子对分类帮助不大。作为一种智能分类方法,C5.0决策树分类方法应用于30m分辨率的时间序列HJ-1A/B CCD数据,能够将地貌复杂的神农架林区植被分为七类,提高了类别精度,具有更高的应用价值。     

A/O—Fenton氧化—混凝组合工艺处理丁苯橡胶生产废水

采用A/O—Fenton氧化—混凝组合工艺处理丁苯橡胶生产废水。试验结果表明:A/O工段中,在兼氧池HRT 8 h、好氧池HRT 16 h、好氧池MLSS 2 500~3 500 mg/L的优化参数下,平均COD,NH3-N,TP去除率分别为72.9%,96.2%,51.3%;Fenton氧化工段中,在30%(w)H2O2溶液加入量0.2%(φ)、n(H2O2)∶n(Fe SO4)=2∶1、Fenton氧化反应时间70 min、Fenton氧化进水p H 5.0的优化条件下,COD和TP的去除率分别为56.0%和57.0%;A/O—Fenton氧化—混凝组合工艺对COD、NH3-N、TP、浊度的总去除率分别为94.8%,96.2%,100%,94.0%,处理后出水满足GB 8978—1996《污水综合排放标准》中的一级标准。     

纳米α-MnO2催化臭氧氧化降解水中双酚A

采用水热法制备了纳米α-MnO₂催化剂,并通过XRD和SEM技术对催化剂的成分和形貌进行了表征。采用纳米α-MnO₂催化剂催化臭氧氧化降解水中的双酚A（BPA）,考察了初始溶液pH、催化剂加入量和反应温度对BPA去除率的影响。实验结果表明,纳米α-MnO₂催化剂催化臭氧氧化降解BPA的最佳工艺条件为：催化剂加入量100 mg/L,初始溶液pH 8.5,反应温度18 ℃。在此最佳条件下处理质量浓度为10 μg/mL的BPA溶液120 min,BPA去除率为96.4%。回收洗涤后第二次使用的催化剂的BPA去除率为80.5%,第三次使用的催化剂的BPA去除率为74.1%,催化剂的活性随重复使用次数的增加而缓慢降低,活性较稳定。     

四溴双酚A降解技术的研究进展

综述了微生物、物理和化学降解技术等几种主要的四溴双酚A（TBBPA）降解技术的研究进展。阐述了各种降解技术的机理和优缺点。指出今后重点的研究方向是：根据不同的反应机理和生长特性分离出微生物降解TBBPA的优势菌种,探索将TBBPA彻底碳化的工艺条件;优化高级氧化法降解TBBPA的反应条件,使之更适于工程应用;将还原法与微生物降解技术或高级氧化法相结合,先将TBBPA快速还原成双酚A,再进一步彻底碳化成CO2和H2O。     

New insights for the risk of bisphenol A: Inhibition of UDP-glucuronosyltransferases (UGTs)

Bisphenol A (BPA), the important endocrine-disrupting chemical (EDC), has been reported to be able to induce various toxicity. The present study aims to understand the toxicity behavior of bisphenol A through evaluating the inhibition profile of bisphenol A towards UDP-glucuronosyltransferase (UGT) isoforms. In vitro recombinant UGTs-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction was employed as probe reaction for all the tested UGT isoforms. The results showed that bisphenol A exerted stronger inhibition towards UGT2B isoforms than UGT1A isoforms. Furthermore, the inhibition kinetic type and parameters (K_i) were determined for the inhibition of bisphenol A towards UGT2B4, 2B7, 2B15, and 2B17. Bisphenol A exhibited the competitive inhibition towards UGT2B4, and noncompetitive inhibition towards UGT2B7, 2B15 and 2B17. The inhibition kinetic parameters (K_i) were calculated to be 1.1, 32.6, 5.6, and 19.9 μM for UGT2B4, 2B7, 2B15 and 2B17, respectively. In combination with the in vivo concentration of bisphenol A, the elevation of exposure dose was predicted to increase by 29.1%, 1%, 5.7%, and 1.6% for UGT2B4, 2B7, 2B15, and 2B17, indicating the high influence of bisphenol A towards the in vivo UGT2B isofroms-mediated metabolism of xenobiotics and endogenous substances. All these data provide the supporting information for deeper understanding of toxicology of bisphenol A.     

Biotransformation of Metamitron by Human P450 Expressed in Transgenic Tobacco Cell Cultures

In the present investigation, the oxidative metabolism of ¹⁴C-labeled metamitron was examined in plant cell cultures of tobacco overexpressing human P450 enzymes CYP1A1 or CYP1A2; special interest was in the aromatic hydroxylation of the herbicide. The oxidative metabolites deaminometamitron (DAM) and 4-hydroxydeaminometamitron (4-HDAM) were found in the untransformed control culture as well as in the transgenic culture. The transgenic cultures, however, exhibited higher turnover rates after 48 h of incubation with 20 μg ¹⁴C-metamitron per assay (untransformed: 40%, CYP1A1: 80%, CYP1A2: 100%). Primary metabolite 4-HDAM was partially found in glucosylated form in the transgenic cultures. As minor oxidative metabolites, 6-hydroxyphenyl-3-methoxymethyl-1,2,4-triazine-5(4H)-one and 3-hydroxymethyl-6-phenyl-1,2,4-triazine-5(4H)-one were identified in the transgenic cultures by GC-MS, LC-MS. Additionally, it could be demonstrated that both foreign enzymes (CYP1A1, CYP1A2) also catalyzed the deamination of metamitron. In a large-scale study (up to 400 μ g per assay) with the transgenic culture expressing CYP1A2, the high efficiency of this P450 system toward metamitron was demonstrated: turnover of the xenobiotic was almost complete with 400 μ g. Since large portions of unglucosylated 4-H-DAM were found, the activity of foreign CYP1A2 apparently exceeded that of endogenous O-glucosyltransferases of the tobacco cell culture. We concluded that in comparison to the nontransformed cell culture, the extent of metabolism was considerably higher in the transgenic cultures. The transgenic cell cultures expressing human CYP1A1 or CYP1A2 are thus suitable tools for the production of large quantities of primary oxidized metabolites of metamitron.     

Effect of additives in the Neem formulations on deposition,volatilization and persistence of Azadirachtin in spruce foliage

Abstract

Foliar deposits, volatilization and persistence of azadirachtin‐A (AZ‐A) were investigated after application of four spray mixes prepared from a wettable powder (WP) and three emulsifiable concentrate (EC) formulations of neem. They were applied at the dosage rate of 50 g AI in 4 L/ha onto potted spruce seedlings in a laboratory spray chamber. Droplet‐size spectra and deposits were assessed using Kromekote^® card/glass plate collection units. Foliar residues [dislodgeable residues (DR), penetrated residues (PR) and total residues (TR)] of AZ‐A and their volatilization were measured by HPLC at different intervals of time up to 60 h after treatment. Differences in the droplet‐size spectra and deposit levels were observed among the four spray mixes due to the influence of additives present in them. Dissipation half‐lives (DT₅₀) of the DR, PR and TR in the foliage were low (range, 19.5 to 38.9 h) and varied according to the residue type and the spray mix used. The DT₅₀ values of the DR were consistently lower (range, 19.5 to 31.9 h) than those of the PR (range, 30.5 to 38.9 h) due to preferential loss of the surface residues. The low DT₅₀ values observed for the DR and TR in the foliage sprayed with the WP spray mix were attributed to the particulate nature of the deposit. AZ‐A volatilized appreciably from the DR rather than from the PR. The variations found in the amounts of AZ‐A volatilized (42 to 58%) and unaccountable (38 to 46%) from the initial TR values in spruce foliage, after 60 h, were attributed to the physical form of the deposits on the target surface and the influences of additives present in the different spray mixes.     

Sorption of 17α-ethinyl estradiol, bisphenol A and phenanthrene to different size fractions of soil and sediment

The potential for negative effects caused by endocrine disrupting chemicals (EDCs) release into the environment is a prominent concern and numerous research projects have investigated possible environmental fate and toxicity. However, their sorption behavior by size fractions of soil and sediment has not been systematically represented. The sorption of bisphenol A (BPA), 17α-ethinyl estradiol (EE2) and phenanthrene (Phen) by different size fractions of soil and sediment were investigated. Sorption isotherms of EE2, BPA, and Phen by size fractions of soil (SL) and sediment (ST) were well fitted to the Freundlich model. The positive correlation between EE2, BPA and Phen sorption capacity (log K_d) of size fractions and their organic carbon (OC) content suggests that OC of size fractions in SL and ST should regulate sorption, while the surface area (SA) of size fractions may not account for sorption of EE2, BPA and Phen. Each size fraction of ST had higher sorption capacity (K_d or K_OC) of EE2 and BPA than that of SL due to their difference in the polarity of organic matter (OM) between terrestrial and aquatic sources. Sorption capacity logK_d for size fractions of SL and ST did not follow the order: clay > silt > sand due to the difference in OM abundance and composition between the size fractions. Large particle fractions of ST contributed about 80% to the overall sorption for any EE2, BPA, and Phen. This study was significant to evaluate size fractions of soil and sediment as well as their associated OM affecting EE2 and BPA sorption processes.     

Bisphenol A in human placental and fetal liver tissues collected from Greater Montreal area (Quebec) during 1998-2008

In this study, the presence of bisphenol A (BPA) in human placental and fetal liver samples collected from 1998 to 2008 was investigated to provide a more detailed analysis of the transfer of BPA across the placenta and fetal exposure to BPA. The average concentrations in placental samples were 12.6 ng g⁻¹ for free BPA, 17.2 ng g⁻¹ for BPA-glu, and 30.2 ng g⁻¹ for total BPA. The highest concentrations in placental samples were 165 ng g⁻¹ for free BPA, 178 ng g⁻¹ for BPA-glu, and 280 ng g⁻¹ for total BPA. Samples with higher levels of BPA-glu had higher levels of free BPA in general. Fetal age was observed to have a significant effect on BPA-glu levels in placental samples, but not on free or total BPA. The percentages of free BPA relative to total BPA for the placental samples varied considerably from 4.2% to 100%, suggesting that the ability of maternal liver and/or the placenta to conjugate BPA is highly variable during early to mid-gestation. The average concentrations in fetal liver samples were 9.02 ng g⁻¹ for free BPA, 19.1 ng g⁻¹ for BPA-glu, and 25.8 ng g⁻¹ for total BPA. The highest concentrations in fetal liver samples were 37.7 ng g⁻¹ for free BPA, 93.9 ng g⁻¹ for BPA-glu, and 123 ng g⁻¹ for total BPA. The percentages of free BPA level relative to total BPA for all fetal liver samples varied from 12.4% to 99.1%, indicating extensive variability in the ability of the human feto-placental unit to glucuronidate BPA.     

小区生活污水的治理方案

对小区排污状况进行现场调查、分析和试验的基础上,综合对比目前处理小区生活污水的几种常用工艺,结合本小区的实际情况,提出用A／O法治理该小区的生活污水,治理后的废水出水水质达到国家废水综合排放标准(GB8978—96)二级标准,并且部分回收再利用。