基于WSR-TOPSIS的学生公寓火灾风险评价

针对学生公寓导致火灾的因素繁多且复杂的特点,为了有效预防和减少学生公寓火灾事故的发生,提出了基于WSR-TOPSIS的学生公寓火灾风险评价方法.首先,在WSR理论基础上构建学生公寓火灾风险评价体系,其次应用G1法、熵权法和方差最大化理论分别计算主观权重、客观权重和组合权重,最后使用TOPSIS法得出评价结果.将所建立的模型应用于陕西省西安市4所高校的学生公寓火灾风险评价中,得出了各评价对象的火灾风险等级和排名.研究表明,所建立的模型能够应用于学生公寓火灾风险评价中,具有可行性与合理性.     

土霉素对小麦种子发芽与幼苗生长发育的生态毒性

研究了土霉素对小麦种子发芽以及早期幼苗生长发育的生态毒性效应.结果表明,土霉素对小麦种子芽长及根长的抑制效应显著(p<0.01),而且它们之间具有良好的剂量-效应关系.根据线性回归方程得出土霉素对小麦种子芽长和根长的半抑制浓度为65.5 mg/L和34.7 mg/L.然而,土霉素对小麦种子的发芽率并没有显著的影响.研究还表明,0.15~2.4 mg/L土霉素暴露21 d后,小麦叶片中的叶绿素含量降低了35.6%~47.3%,叶片及根部的可溶性蛋白含量也均呈显著下降趋势.暴露7 d后,0.15~2.4 mg/L土霉素对小麦叶片和根部SOD与POD活性的抑制效应不显著,但随着暴露时间的延长,土霉素对小麦的SOD与POD酶活性抑制率显著下降;2.4 mg/L土霉素暴露21 d后,小麦根部的SOD活性下降72.3%,说明土霉素对小麦幼苗体内的抗氧化系统具有破坏作用.该实验结果显示,低浓度土霉素长期暴露对小麦幼苗的生长发育具有不良的生态毒性效应.     

铜锈环棱螺对镉污染沉积物慢性胁迫的生物标志物响应

沉积物毒性测试是评价水生态系统中沉积物污染生态风险的重要手段.建立合适的毒性测试生物是进行沉积物毒性测试的基本前提.铜锈环棱螺(Bellamya aeruginosa)在我国淡水水体中分布广泛,具有重要的生态价值.本研究将实验室培养的铜锈环棱螺暴露于不同含量的镉加标沉积物中28d,以评价该物种在镉污染沉积物慢性胁迫下生物标志物响应的敏感性.结果表明,除了谷胱甘肽(GSH)相对不敏感外,壳长增长率、肝胰脏超氧化物歧化酶(SOD)和过氧化氢酶(CAT)、以及肝胰脏和肾脏中的金属硫蛋白(MT)均表现出相对较高的敏感性,可用作重金属污染沉积物慢性胁迫的有效生物标志物.尤其是肝胰脏SOD和CAT可以用作指示低水平镉污染沉积物长期污染胁迫下的敏感生物标志物.此外,该物种的实验室培养和毒性测试操作容易进行,可以考虑将铜锈环棱螺作为我国淡水沉积物毒性评价的候选物种.     

Using the nematode Caenorhabditis elegans as a model animal for assessing the toxicity induced by microcystin-LR

Among more than 75 variants of microcystin(MC),microcystin-LR(MC-LR) is one of the most common toxins.In this study,the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied.C.elegans was treated with MC-LR at different concentrations ranging from 0.1 to 80 μg/L.The results showed that MC-LR could reduce lifespan,delay development,lengthen generation time,decrease brood size,suppress locomotion behavior,and decreases hsp-16-2-gfp expression.The endpoints of generation time,brood...     

Identification and characterization of the chromium（Ⅵ） responding protein from a newly isolated Ochrobactrum anthropi CTS-325

A Gram-negative, chromium(VI) tolerant and reductive strain CTS-325, isolated from a Chinese chromate plant, was identified as Ochrobactrum anthropi based on its biochemical properties and 16S rDNA sequence analysis. It was able to tolerate up to 10 mmol/L Cr(VI) and completely reduce 1 mmol/L Cr(VI) to Cr(III) within 48 h. When the strain CTS-325 was induced with Cr(VI), a protein increased significantly in the whole cell proteins. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis revealed that this protein was a superoxide dismutase (SOD) homology. The measured superoxide dismutase activity was 2694 U/mg after three steps of purification. The SOD catalyzes the dismutation of the superoxide anion (O₂^·−) into hydrogen peroxide and molecular oxygen. This protein is considered to be one of the most important anti-oxidative enzymes for O. anthropi as it allows the bacterium to survive high oxygen stress environments, such as the environment produced during the reduction process of Cr(VI).     

Early stage toxicity of excess copper to photosystem II of Chlorella pyrenoidosa–OJIP chlorophyll a fluorescence analysis

Acute toxicity of excess Cu on the photosynthetic performance of Chlorella pyrenoidosa was examined by using chlorophyll a fluorescence transients and JIP-test after exposure to elevated Cu concentrations for a short time period. High Cu concentration resulted in a significant suppression in photosynthesis and respiration. The absorption flux (ABS/RC) per PSII reaction center increased with increasing Cu concentration, but the electron transport flux (ET₀/RC) decreased. Excess Cu had an insignificant effect on the trapping flux (TR₀/RC). The decline in the efficiency, with which a trapped exciton can move an electron into the electron transport chain further than Q_A−(Ψ₀), the maximal quantum yield of primary photochemistry (?_P0), and the quantum yield of electron transport (?_E0) were also observed. The amount of active PSII reaction centers per excited cross section (RC/CS) was also in consistency with the change of photosynthesis when cells were exposed to excess Cu concentration. JIP-test parameters had a good linear relationship with photosynthetic O₂ evolution. These results suggested that the decrease of photosynthesis in exposure to excess Cu may be a result of the inactivation of PSII reaction centers and the inhibition of electron transport in the acceptor side.     

科技解构传统权力基础

珠宝都有自己的个性、3D画面在空气中即能展示、电子婴儿流行一时、细菌可以排雷,甚至战争只伤害设备系统而不伤害士兵……这些听起来似乎是天方夜谭,不过远在伦敦的Ian Neild坚持认为,它们真的很快就会来到我们身边。     

红霉素废液生产单细胞蛋白的发酵条件研究

采用单因素及正交方法,以微生物含量为主要检测指标,研究红霉素废液生产单细胞蛋白的工艺条件。探讨了接菌量、发酵培养基中废液含量、发酵时间、发酵pH值、氮源等因素对单细胞蛋白产量的影响。结果表明,红霉素废液发酵生产蛋白的适宜条件为:发酵培养基中废液含量20%,接菌量6%,pH=6,发酵时间72h。     

地球化学勘查综合定量评价在赣东南大墩矿区的应用

赣东南大墩地区铜金多金属矿化主要产于晚三叠世黑云正长花岗岩与南华系接触带附近,受南华系浅变质岩地层岩性及断裂破碎带控制明显.本文以该区1:5万矿产远景调查项目大墩靶区成功找矿为例,基于MAPGIS软件系统,对勘查区进行了化探数据处理、化探异常剖析、元素聚类分析、元素定量统计分析、剥蚀程度定量评价等综合定量评价.工作成果表明, 勘查区显示铜金为主要矿种、银铅锌为伴生矿种的中低温热液型矿床特征,矿化类型主要为石英脉型,矿床可达小型-中型规模.在风化剥蚀面显露出金铜等近矿地球化学原生晕指示元素.根据地球化学勘查综合定量指标分析,认定大墩地区为面积约15 km2具有中型铜金多金属矿产地勘查前景的找矿靶区.应用以上成果,该区已取得明显找矿效果.     

新型城市污水脱氮除磷工艺的试验研究与优化设计

提出了一种改进型A2/O脱氮除磷工艺(MAAO),通过工艺试验和活性污泥2D模型对其进行运行和设计优化.结果表明,系统对COD、TN、NH 4-N和TP的平均去除率分别为85.7%、66.8%、97.35%和78.1%;当COD在300mg/L以上时,脱氮除磷效果均较好,可分别达到70%和90%以上.基于试验结果建立的MMAO工艺数学模型仿真效果良好,可对各单元组合进行优化,校核预测不利工况下的工艺运行效果,实现工艺不同工况下的运行参数优化,较好地实现新工艺的机理性优化设计和运行. MMAO稳定运行出水可达到<城镇污水处理厂污染物排放标准>(GB 18918-2002)一级B标准.由于工艺省去内回流,增加厌氧混合液部分超越提供反硝化碳源,使得运行费用明显降低;系统总停留时间比目前传统的以去除有机污染物为主的生物处理工艺略低,该工艺非常适用于对不具有脱氮除磷功能污水厂的改造.