Preparation of hydrogen-rich gas from waste polyurethane foam by steam gasification and catalytic reforming in a two-stage fixed bed reactor

Journal of Material Cycles and Waste Management - The reclamation of waste rigid polyurethane foam (WRPUF) is capable of realizing both circulations of waste and protection of the environment. In...     

The profile of antibiotics resistance and integrons of extended-spectrum beta-lactamase producing thermotolerant coliforms isolated from the Yangtze River basin in Chongqing

The spreading of extended-spectrum β-lactamases (ESBL)-producing thermotolerant coliforms (TC) in the water environment is a threat to human health but little is known about ESBL-producing TCs in the Yangtze River. We received 319 ESBL-producing stains obtained from the Chongqing basin and we investigated antibiotic susceptibility, bla gene types and the presence of integrons and gene cassettes. 16.8% of TC isolates were ESBL-producing bacteria and bla_TEM+CTx-M was the predominant ESBL type. 65.2% of isolates contained class 1 integrons, but only 3 carried intI 2. Gene cassettes were amplified and sequenced. aadA, drfA, cmlA, sat1, aar3 and two ORF cassettes were found. In conclusion, Yangtze River is heavily polluted by ESBL-producing TC bacteria and the combined bla gene type could enhance antibiotic resistance. Class 1 integrons were widespread in ESBL-producing isolates and play an important role in multi-drug resistance. Characterization of gene cassettes could reveal the dissemination of antibiotic resistance genes.     

Homology modeling of anti-parathion antibody and its interaction with organophosphorous pesticides and analogues

The mechanism of specific recognition in pesticide immunochemistry was investigated by computer-based strategy, and a rapid method for the identification of antibody specificity was developed. Based on the previously produced anti-parathion monoclonal antibody (mAb), the DNA sequence was analyzed by polymerase chain reaction (PCR). From the translated amino acid sequences, a three-dimensional structure of the antibody was constructed by homology modeling method, and then it was coordinated by 1 ns molecular dynamics under the explicit solvent condition. The stereochemical property and folding quality were further assessed by Procheck and Profile-3D. The self-compatibility score for the antibody model was 98.7, which was greater than the low score 46.2 and close to the top score 102.6. In addition, parathion and several structural analogues were docked to the constructed antibody structure. The docking results showed that the interaction energy (-40.54 kcal/mol) of antibody-parathion complex was the lowest among all the tested pesticides, which accounted for the high specificity of the antibody to parathion and perfectly matched with the experimental data. Moreover, three residues, Phe165, Asp107 and Thr100 were recognized as the most important residues for antibody reacting with parathion. The interaction energy negatively correlated with the antibody specificity.     

我国工业SO2排放趋势及影响因素分析

分析了我国工业SO2排放量的变化趋势，以及其与GDP、工业产值、火电厂发电量等指标的变化关系；利用50个省市1998—2007年的有关数据建立了SO2排放量的影响因素面板数据模型，力求通过定量分析识别影响我国工业SO2排放量的关键因素。研究表明，我国工业SO2排放量与第二产业比重、火力发电比重并无明显关系，而GDP、发电量、一次能源转化效率、SO2去除率存在显著关系，对SO2工业实际排放量起决定作用的是SO2的去除率。     

城镇社区地震应急能力评价指标体系的构建

城镇社区是构成城镇的基本单元,是政府实施社会管理的基本单元和主要依托,也是城镇防灾减灾的基本单元.城镇社区地震应急能力评价是地震应急管理的重要内容,建立社区地震应急能力评价指标体系对提高社区地震应急能力、建设地震安全社区和促进城镇地震应急管理工作具有重要意义.     

Differences in plant species diversity between conifer (<Emphasis Type="Italic">Pinus tabulaeformis</Emphasis>) plantations and natural forests in middle of the Loess plateau

We compared differences in plant species diversity between conifer (Pinus tabulaeformis) plantations and natural secondary forests in the middle of the Loess plateau. The goal of the study was to examine the differences in the effect of stand development on species diversity and in species responses to changes between forest types and between forest layers. To clarify the effects of differences in forest management, we emphasized the functional types of plant species occurring in each forest type. The result as follow: (1) The H′ and S of tree layer were significantly lower in natural conifer forest than old conifer and secondary forest, but were not different compared with mid aged conifer forest. The H′ and S of shrub layer were significantly lower in mid aged conifer forest compared with other forest types. The H′ of herb layer showed no significant differences in the four forest types. The evenness index (J′) of tree layer of mid aged conifer forest was lower than other forest communities and its J′ of shrub layer was highest although its richness of shrub layer was lower than in the other forest types. (2) The analysis of β diversity index also indicated large differences between conifer plantations and natural forests. Although the tree layer species were similar in old plantation and natural conifer forests, they differed greatly between the natural conifer and secondary forests. The natural conifer and secondary forest species composition in shrub layer differed significantly from those in plantation and secondary plots. Tree species were significantly less common in plantations than in abandoned coppice forests. Species composition in the herb layer of different forest types was similar. (3) The management of P. tabulaeformis plantations alters plant species composition considerably; the number of sub tall-tree species is increased in old aged conifer forest, especially species dispersed by animals. Plantation management appears to affect ecological processes through seed dispersal. From the perspective of management, the change in the structure and composition of the canopy in plantations could affect the behavior of dispersers and regeneration.     

镉胁迫对向日葵幼苗生长和生理特性的影响

采用溶液培养方法,研究了不同浓度镉(0、0.05、0.1、0.5和1 mg/L)处理7 d对向日葵幼苗生长和生理特性的影响。结果表明：随着镉处理浓度的增加，向日葵幼苗对镉的吸收显著增加。1 mg/L镉浓度处理时，叶、茎和根中镉浓度分别为0.05 mg/L镉处理时的16.3、19.2和581倍；根中积累的镉含量明显高于叶和茎, 各浓度根部积累的镉分别为叶和茎的37.8～63倍和29.4～41倍。镉胁迫显著抑制向日葵幼苗生长和叶绿素合成，当镉浓度达1 mg/L时，整株植物生物量和总叶绿素含量分别为对照的55.9%和52.6%。镉胁迫下向日葵幼苗游离脯氨酸和丙二醛（MDA）含量显著增加，1 mg/L镉浓度时，根中含量分别为对照的4和5.8倍。向日葵幼苗可溶性蛋白含量和过氧化物酶(POD)活性变化与镉胁迫浓度呈明显的倒U字型关系，可溶性蛋白含量在0.05 mg/L镉浓度时达到最大值，叶、茎、根中的POD活性分别在0.1、0.1和0.05 mg/L镉浓度时达到最大值。     

生物接触氧化/超滤/反渗透法处理稠油污水试验研究

采用生物接触氧化/超滤/反渗透工艺,对陈家庄稠油污水进行了深度处理回用注汽锅炉给水试验研究.试验结果表明,进水含油量为8.1～67.0 mg/L,浊度为35～120 NTU,矿化度为10 454～11 354 mg/L时,生物接触氧化/超滤出水含油量为<0.8 mg/L,浊度为<0.5 NTU,污染密度指数(SDI)<3,各项指标满足反渗透进水要求.反渗透出水矿化度<950 mg/L,出水各项指标优于高压注汽锅炉进水指标.     

有机磷降解酶的固定化及其工业化应用初探

采用一种新型的酶固定化方法，在大孔微球中对有机磷降解酶（OPHC2）固定化，制备固相载体化的交联酶聚集体固定化酶。对具有实际应用意义的参数：热稳定性、牢固度和连续反应批次进行了重点研究。结果表明，有机磷降解酶固定化酶的半衰期在70℃时比游离酶提高了2.1倍。固定化酶分别在37℃的摇床中经14 h高速振荡，以及在pH 8、37℃条件下循环反应49个批次降解甲基对硫磷后，均未发现固定化酶酶活力下降。在37℃，有机磷降解酶固定化酶柱以每小时3倍柱床体积的速率对甲基对硫磷农药乳油的稀释液（甲基对硫磷含量为216 mg/L）进行降解处理，系统连续工作156 h，甲基对硫磷的降解率保持在98.4%～99.9%。     

Tracer-based source apportionment of polycyclic aromatic hydrocarbons in PM2.5 in Guangzhou, southern China, using positive matrix factorization (PMF)

From 28 November to 23 December 2009, 24-h?PM_2.5 samples were collected simultaneously at six sites in Guangzhou. Concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) together with certain molecular tracers for vehicular emissions (i.e., hopanes and elemental carbon), coal combustion (i.e., picene), and biomass burning (i.e., levoglucosan) were determined. Positive matrix factorization (PMF) receptor model combined with tracer data was applied to explore the source contributions to PAHs. Three sources were identified by both inspecting the dominant tracer(s) in each factor and comparing source profiles derived from PMF with determined profiles in Guangzhou or in the Pearl River Delta region. The three sources identified were vehicular emissions (VE), biomass burning (BB), and coal combustion (CC), accounting for 11?±?2 %, 31?±?4 %, and 58?±?4 % of the total PAHs, respectively. CC replaced VE to become the most important source of PAHs in Guangzhou, reflecting the effective control of VE in recent years. The three sources had different contributions to PAHs with different ring sizes, with higher BB contributions (75?±?3 %) to four-ring PAHs such as pyrene and higher CC contributions (57?±?4 %) to six-ring PAHs such as benzo[ghi]perylene. Temporal variations of VE and CC contributions were probably caused by the change of weather conditions, while temporal variations of BB contributions were additionally influenced by the fluctuation of BB emissions. Source contributions also showed some spatial variations, probably due to the source emission variations near the sampling sites.