中国、印度及环境

——中印合作可以降低生物多样性损失、减轻气候变化并减少森林砍伐。中国和印度这两个新兴的世界经济大国将对21世纪世界环境发挥重要甚至主导作用。在未来几年内,两国的经济增长率预期将维持8%～9%。在世界很多国家出现经济危机情况下,中印两国2009年仍实现了国内生产总值高增长(中国:8.4%,印度:6.2%,世     

Impacts of ultrasound on selective leaching recovery of heavy metals from metal-containing waste sludge

Lab synthesized metal-bearing sludge (LSMS) was used in series of designed lab tests to evaluate impacts of ultrasound on selective separation of heavy metals through acid leaching. The tests eliminated the potential of induced bias generated by utilizing field sludge that were produced from different location sources. The results showed that metal pairs of Cu and Fe, Cu and Cr, and Cr and Fe inside LSMS could be practically separated with one metal being contained in a liquid phase and another in a solid phase through acid leaching processes enhanced by ultrasound. With assistance of ultrasound, the acid leaching demonstrated a more efficient segregation between metals within LSMS than a conventional leaching that doesn’t have ultrasonic enhancement, and the tests provided in a generic means that ultrasonically enhanced acid leaching could cost-efficiently recover heavy metals from metal-containing waste sludge.     

基于序次Probit模型的航道船舶碰撞危险度研究

船舶碰撞严重威胁着船舶水上航行的安全,船舶碰撞危险度的研究能够为船舶避碰提供有效的预防手段和合理的科学依据。选取航道船舶碰撞危险度作为状态变量,选取船舶会遇方式、风速和能见度作为控制变量,运用序次Probit模型拟合出碰撞危险度状态方程。分别对人为判断和序次Probit模型的碰撞危险度利用插值技术,描绘出控制变量对状态变量的作用效果变化特征图。研究结果表明,拟合状态方程可以良好地表征系统状态的连续变化特征,序次Probit模型能够有效克服人为判断的不确定性。     

朱砂叶螨乙酰胆碱酯酶的原核表达及其活性分析

乙酰胆碱酯酶(ACh E)在神经信号传导过程中起重要作用,是氨基甲酸酯类和有机磷类农药的主要作用靶标.对朱砂叶螨ACh E进行体外表达和纯化,并分析其活性.将朱砂叶螨ace基因序列插入到原核高效表达载体p ET-30a中,构建表达载体p ET-30a/ace,转入表达菌株Escherichia coli BL21(DE3)中,IPTG诱导高效表达;镍柱纯化目的蛋白,经SDS-PAGE和Western Blot鉴定目的蛋白;以纯化的螨ACh E为抗原制备抗螨ACh E特异性抗体;改良的Ellman法测定螨ACh E活性.结果获得了相对分子质量(Mr)约为68×103的较高纯度的螨ACh E蛋白,检测大部分为可溶性表达,酶活检测具有乙酰胆碱酯酶活性,并制备了107效价的抗螨ACh E特异性抗体.采用重组ACh E(IC50=5.4 mmol/L)检测毒扁豆碱抑制活性比螨粗酶液(IC50=58.7 mmol/L)灵敏度提高11倍.本研究构建了螨ACh E体外高效表达载体并获得了具有较好活性的重组螨ACh E,可为抗ACh E杀螨剂的体外高通量筛选和以ACh E为靶标的农药残留检测奠定基础.     

Birds defend oil palms from herbivorous insects.

Top-down forces are expected to be important in regulating herbivore populations in most agricultural systems where primary productivity is high and species diversity is low. Under such conditions, trophic cascades are predicted to occur when predator populations are reduced or removed. Studies on how predator removal indirectly affects herbivory rates in agricultural systems are lacking. Through a bird-exclosure experiment, I test the hypothesis that insectivorous birds indirectly defend oil palms (Elaeis guineensis) from herbivorous insects. Results show that bird exclusion significantly increased herbivory damage to oil palms, and that the size of this exclusion effect increased with bird density, although the latter result was not statistically significant. These findings suggest that insectivorous birds deliver a natural pest control service for oil palm agriculture, which is important not only for the direct benefits it delivers for human welfare, but also in strengthening the economic justifications for conserving the remaining natural habitats and biodiversity in agricultural landscapes.     

环境中重金属暴露对抗生素抗性基因演变影响研究进展

抗生素抗性基因(ARGs)已被列为环境新兴污染物,其污染散播和环境演变已成为生态环境领域的关注焦点和研究热点。重金属因其不可降解性,可在自然环境中稳定存在,具有长期生物可利用度,对ARGs会产生持续性选择性压力影响。综述了细菌在抗生素、重金属,以及二者协同作用条件下的不同抗性机制,重点探讨了重金属对ARGs存在丰度和水平转移等环境行为的过程影响。结果表明:多种重金属及其化合物会对ARGs的丰度和水平转移产生影响,根据重金属的种类以及浓度不同可能会产生不同的影响结果;重金属影响ARGs水平转移主要是通过影响细胞分泌胞外聚合物(EPS)、改变细胞膜通透性以及影响基因表达等方式,不同种类的重金属可通过不同的方式影响ARGs的水平转移。虽然目前关于重金属对ARGs环境行为的过程影响已有较多研究报道,但是针对重金属对ARGs影响的内在机制以及不同环境介质中重金属对ARGs丰度和水平转移的协同选择作用有待进一步的研究。     

新型多孔高分子载体厌氧流化床启动实验研究

制备了两种不同孔径（ｄ＞０．５μｍ）分率的聚丙烯酸酯类多孔载体，与多孔颗粒活性炭（ＧＡＣ）在完全相同的启动条件下，作厌氧流化床固定化微生物对比实验．结果表明：新型高分子载体能有效促进厌氧菌固定化速度，可比ＧＡＣ缩短反应器启动时间１５ｄ左右；扫描电镜观察发现，多孔高分子生物颗粒球形度高，表面生物膜致密坚实，内孔微生物聚集丰富，而ＧＡＣ生物颗粒形状不规则，表面生物膜疏松呈鳞片状，内孔不易驻留微生物．另外，根据高分子载体内孔产甲烷丝菌的形态和分布特征，获取了当生物膜持续增厚后（δ＞１００μｍ），基质扩散阻力影响内孔微生物活性的证据．     

APPLICATION OF TABU SEARCH TO GROUND WATER PARAMETER ZONATION1

ABSTRACT: The spatial distribution of hydrogeologic parameter is an important issue in ground water simulation. One of the methods is to divide an area into several zones such that parameters are assumed to be constant within zone. The purpose of this study is to apply Tabu Search (TS) to find the best zonation of parameters that can result in the best ground water simulation. The initial zonation can be determined as the Thiessen method, and then zonation is optimized by T.S. The mean square error between simulated and observed hydraulic heads was used as the objective function. A designed confined aquifer with known zonation was used as an example to test the proposed method. Results indicated that Tabu Search can locate the optimal zonation successfully and avoid being trapped by local optimal zonations. Besides this, four other arbitrary initial zonations can be directed to the optimal zonation by TS, which proves the robustness of the proposed method. The method proposed in this study is feasible and expected to work well in the field problems with sufficient sampling of concerned parameters.     

风帽在准好氧填埋的应用及对填埋初期的影响

首次将风帽应用于准好氧填埋,以2 m×1 m×2 m的准好氧模拟箱为对象,考察了风帽对准好氧填埋环境形成过程的影响,比较了不同风速条件下二氧化碳和甲烷的浓度变化,并对风帽应用于准好氧填埋的作用原理进行了分析,以期为设计和优化准好氧填埋结构提供参考.结果表明,风帽可以加快准好氧环境的形成,将传统的准好氧环境的形成期由常规的50 d以上提前到40 d左右.通过比较风帽先拆后装二氧化碳和甲烷的浓度变化,表明风帽可以促进甲烷向二氧化碳的转化,减少甲烷的排放.卸下风帽后二氧化碳的浓度由最初的16.67%降为15.88%,甲烷从6.14%增大到16.12%;装上后二氧化碳的浓度增至19.18%,甲烷降为10.05%.考察了风速为2.0、3.5、5.0、6.5、8.0 m/s 5种条件下导气管出口处的甲烷排放情况,表明风速可以加强风帽的作用,有利于甲烷的减排,当风速增至8 m/s时,甲烷浓度由最初的15%以上降为5%以下.     

Fatty acid fouling of forward osmosis membrane: Effects of pH, calcium, membrane orientation, initial permeate flux and foulant composition

Octanoic acid (OA) was selected to represent fatty acids in effluent organic matter (EOM). The effects of feed solution (FS) properties, membrane orientation and initial permeate flux on OA fouling in forward osmosis (FO) were investigated. The undissociated OA formed a cake layer quickly and caused the water flux to decline significantly in the initial 0.5 hr at unadjusted pH 3.56; while the fully dissociated OA behaved as an anionic surfactant and promoted the water permeation at an elevated pH of 9.00. Moreover, except at the initial stage, the sudden decline of water flux (meaning the occurrence of severe membrane fouling) occurred in two conditions: 1. 0.5 mmol/L Ca^2 +, active layer facing draw solution (AL-DS) and 1.5 mol/L NaCl (DS); 2. No Ca^2 +, active layer-facing FS (AL-FS) and 4 mol/L NaCl (DS). This demonstrated that cake layer compaction or pore blocking occurred only when enough foulants were absorbed into the membrane surface, and the water permeation was high enough to compact the deposit inside the porous substrate. Furthermore, bovine serum albumin (BSA) was selected as a co-foulant. The water flux of both co-foulants was between the fluxes obtained separately for the two foulants at pH 3.56, and larger than the two values at pH 9.00. This manifested that, at pH 3.56, BSA alleviated the effect of the cake layer caused by OA, and OA enhanced BSA fouling simultaneously; while at pH 9.00, the mutual effects of OA and BSA eased the membrane fouling.