Long-term monitoring and source apportionment of PM2:5/PM10 in Beijing, China

During 2001-2006,PM2.5 (particle matter with aerodynamic diameter less than 2.5 microns) and PM10 (particle matter with aerodynamic diameter less than 10 microns) were collected at the Beijng Normal University (BNU) site,China,and in 2006,at a background site in Duolun (DL).The long-term monitoring data of elements,ions,and black carbon showed that the major constituents of PM2.5 were black carbon (BC) crustal elements,nitrates,ammonium salts,and sulfates.These five major components accounted for 20%-80% of...     

重金属抗性菌Bacillus cereus HQ-1对银离子的生物吸附-微沉淀成晶作用

发现1株对银离子有强吸附能力的蜡状芽孢杆菌HQ-1,研究了其对银离子的吸附特性及吸附机理.结果表明,菌体对银的吸附量可达91.75 mg/g,吸附过程符合Pseudo-second Order吸附动力学模型,相关系数高达0.999 9;吸附热力学很好地符合Freundlich吸附等温模型,相关系数为0.99;考察菌体浓度和温度对吸附的影响发现,菌体浓度增加有利于对银离子的吸附,温度对吸附影响较小;FTIR、SEM及EDAX实验结果表明吸附存在2种吸附机理,一为菌体表面一些含氮氧的基团对Ag 的络合作用,二为菌体分泌的胞外多糖等物质对Ag 的微沉淀成晶作用.     

碳纳米管对阿特拉津的吸附/解吸特性

采用批量实验研究了不同溶液条件下阿特拉津(AT)在单壁碳纳米管(SWNT)和多壁碳纳米管(MWNT)上的吸附/解吸行为.实验结果显示,离子强度对AT在SWNT和MWNT上的吸附没有显著影响,但随着pH值的增大,AT在2种碳纳米材料上的吸附量显著增加;这表明,AT在溶液中的存在状态是吸附的主要影响因素.在本实验的研究条件下,AT从SWNT和MWNT上的解吸行为不存在明显的滞后效应.碳纳米管对AT较高的吸附容量和吸附的可逆性表明,碳纳米管的大规模应用将可能带来一定的环境和健康风险.     

Inhibitory effects of four plants flavonoids extracts on fatty acid synthase

Fatty acid synthase (FAS) had been found overexpress and hyperactive in most cancers. Pharmacological inhibitors of FAS activity preferentially repress cancer cell proliferation and induce cancer cell apoptosis without affecting nonmalignant fibroblasts. These made FAS an excellent drug target for cancer therapy. The activity of FAS in 11 different kinds of cancer cells, including esophageal carcinoma (EC109, EC8712, H5E973), gastric carcinoma (N87, BGC823), lung carcinoma (A549, 95-D), hepatoma (HepG2), uterine cervix cancer (HeLa) and leukaemia (K562, U937) were compared using spectrophotometric method. We selected the cell line with the highest FAS activity as cell model to study the inhibitory effect of the flavonoids extracts on FAS. Four plants including Canavium album Raeuseh leaves, Bombax ceiba Linn, Brassica albograbra Bailey, and Citrus reticulata Blanco were selected for extracting flavonoids. The results showed significantly different FAS activity among different cancer cells. The FAS activity is the lowest in gastric cancer cell N87 (15.91 ± 3.61 U/mg protein) and the highest in lung cancer cell A549 (127.36 ± 10.14 U/mg protein). The cancer cell A549 was used as cell model to test the inhibitory effort of flavonoids extracts on FAS. Results showed that the flavonoids extracts of Citrus reticulata Blanco and Canavium album Raeuseh leaves have higher inhibitory effect on FAS activity compared with the universally used FAS inhibitor C75 and both extracts inhibit cancer cell proliferation when added to cultured cancer cells. These studies provided a good cell model for testing the inhibitory effect on FAS activity and suggested that Citrus reticulata Blanco rind and Canavium album Raeuseh leaves are good biomaterials for separating and purifying natural flavonoids FAS inhibitors and exploring their inhibitory mechanisms.     

Acidibility established as a characteristic of high strength organic wastewater quality

Acidification processes of the alcohol wastewater on molasses and the sugar-peptone manual make-up water were studied to determine their acidification capability. The two types of wastewater were both diluted into serial gradient dilutions and acidified separately. The volatile fatty acids (VFAs) and were detected daily until acidification reached a maximum state. The degraded COD in each dilution, which were considered as degraded VFAs and analyzed. The ratio of the sum of produced VFAs and degraded VFAs to the initial COD of dilutions was defined as acidibility (V/C). It showed that within a large concentration extent, the V/C values were consistent for different dilutions of each wastewater. Thus acidibility becomes a characteristic of high strength organic wastewater quality. The acidibility of the alcohol wastewater on molasses was analyzed to be 0.71, and the acidibility of sugar-peptone manual make-up water was 0.76. In a practicable view, it is meaningful to set up acidibility as a new water quality index, which can be used to guide the design of acidification technique in various high concentration organic wastewater treatment practices.     

突发公共卫生事件下多阶段应急救援物资配置研究*

为提高突发公共卫生事件背景下应急救援物资分配效率,减少人员伤亡与经济损失,以应急物资需求未满足所导致的损失最小及物资分配总距离最短为目标,研究重大公共卫生事件爆发后不同阶段下应急物资分配问题。构建优化模型,并通过某城市中13个物资需求点的应急物资分配案例验证模型的科学性与合理性。结果表明:本文方法能有效解决动态需求下应急物资分配问题,为解决突发公共卫生事件下应急物资配置提供参考和借鉴。     

我国电子废弃物管理现状及对策研究

随着电子工业的快速发展,越来越多的电子电气产品进入了报废期,带来了巨大的电子废弃物产生量.电子废弃物以高环境风险性和高资源化价值引起了全球的关注.同时,我国的电子废弃物也快速增长,其管理现状亦不容乐观.介绍了国外发达国家(包括欧洲、美国和日本)电子废弃物的管理现状以及分析了我国电子废弃物管理和立法的进程发展.在对我国分析的基础之上,指出目前我国在电子废弃物管理中所存在的问题,问题涉及政策、技术及社会经济等方面;并结合发达国家的先进管理经验,提出针对我国的对策与建议.     

微电解处理电镀含氰废水数学模型的建立

利用origin pro软件和1stOpt软件研究分析铁炭微电解法处理电镀含氰废水的实验数据建立工艺的数学模型。正交试验和单因素试验结果表明最优条件为进水pH值3.5,铁炭体积比2:1,水力停留时间(HRT)60 min,曝气60 min,总氰去除率达96.3%。根据4个变量与总氰去除率间的不同规律关系,运用origin pro软件对其分别进行单因素多项式拟合或S型曲线拟合,建立各自的数学模型,相关系数分别为0.969 9、0.984 6、0.994 8和0.995 8。利用1stOpt软件根据正交试验数据和单因素模型方程进行多元非线性拟合建立宏观数学模型,相关系数达到0.941 3。该模型的参数值比较结果与正交试验测得因素影响次序一致,计算出的模拟值与实验值吻合较好,表明该模型能够正确反应微电解法去除电镀含氰废水中总氰的效果,对后续研究和放大有积极意义。     

超声辅助电催化氧化降解苯酚影响因素的研究

为探讨水体中苯酚的超声辅助电催化氧化降解,考察了超声的频率和声强、溶液的pH值、温度、支持电解质的浓度,电流密度以及苯酚的浓度等因素的影响。在超声声强分别为21.1W/cm2和27.1W/cm2下电催化氧化降解40min,COD去除率分别为59.3%和64.4%,明显高于无超声作用下41.6%的COD去除率;在中性和弱碱性介质中(pH0值在7￣11之间)苯酚的降解效果较好,pH0=10时,苯酚降解的准一级反应速率常数最大;体系的初始pH值超过11,苯酚的降解速率下降很快,这主要是因为体系的碱性太强导致许多副反应的发生,降低了电流效率,反而不利于污染物的氧化降解;溶液中的支持电解质Na2SO4的浓度(CNa2SO4)为10g/L时,苯酚降解的准一级反应速率常数和电催化氧化降解反应时的槽电压均达到最优;在电催化氧化降解过程中,随着电流密度的增加,污染物的氧化降解速率和效率也随之增大。综合考虑降解效率和电流效率两方面因素,电流密度在10￣30mA/cm2范围内较为适宜。     

川西亚高山3个优势树种细根形态特征

林木细根(直径2 mm)拥有庞大而复杂的分枝系统,在森林生态系统养分循环过程中发挥重要作用,因此研究不同树种细根构型形态对树种地下生态位分离、共存和森林生态系统功能过程具有重要意义.选取川西亚高山3个优势树种——岷江冷杉(Abies faxoniana)、粗枝云杉(Picea asperate)和红桦(Butula albosinensis),采用挖掘法采集完整的细根根系,依据根序分级方法,测定细根形态参数(直径、根长、比根长和比表面积).结果表明:细根形态在不同根序间差异显著,3个树种细根直径、根长随根序的升高而升高,比根长和比表面积随序级的升高而降低.不同树种间细根形态也表现出极显著差异,岷江冷杉、粗枝云杉和红桦细直径变化范围分别为0.31-0.85 mm、0.29-0.65 mm和0.23-0.55 mm,两个针叶树种(岷江冷杉和粗枝云杉)直径与根长均大于红桦.红桦的比根长和比表面积则高于两个针叶树种.综上所述,低级别根吸收能力更强而构建消耗更低;红桦比岷江冷杉和粗枝云杉根系吸收能力更强.