3种填料A.ferrooxidans挂膜效果及对模拟酸性矿山废水中Fe2+生物矿化能力比较

氧化亚铁硫杆菌（A.ferrooxidans）介导的生物矿化方法可促使酸性矿山废水（Acid Mine Drainage,AMD）中Fe离子向次生铁矿物转变. 采用固定化的方式来提高A.ferrooxidans密度有助于强化Fe²⁺的生物矿化能力.选取流化床19孔填料、弹性填料、悬浮球填料作为挂膜对象, 通过多批次的连续培养来考察3种填料的A.ferrooxidans挂膜能力及稳定挂膜所需周期,继而比较3种挂膜填料对模拟AMD中Fe²⁺的生物矿化能力,并估算A.ferrooxidans有效生物量.结果表明,3种填料（5.00 g）的A.ferrooxidans挂膜能力依次为弹性填料（1.76 g）＞流化床19孔填料（0.90 g）＞悬浮球填料（0.78 g）（干重）,且挂膜启动至稳定状态至少需要4批次.X射线衍射分析（X-ray diffraction,XRD）表明,3种填料表面 含矿生物膜均为施氏矿物和黄钾铁矾的混合物.以游离态A.ferrooxidans的Fe²⁺氧化速率作为参比,估算出流化床19孔填料、弹性填料、悬浮球填料生物膜中A.ferrooxidans有效生物量依次为1.67×10⁸、8.52×10⁸、1.92×10⁸ cells·g^-1 （干基）.研究还发现,等同Fe²⁺生物氧化速率下, A.ferrooxidans挂膜填料比游离态A.ferrooxidans具有更强的AMD矿化驱动能力.     

南京秋冬季非难熔性亚微米颗粒物来源解析

利用Aerodyne高分辨率飞行时间气溶胶质谱仪（HR-ToF-AMS）对南京北郊秋冬季非难熔性亚微米气溶胶（NR-PM₁）的化学组分（包括有机物、硝酸盐、硫酸盐、铵盐和氯化物）和特征进行实时在线监测,并利用多元线性模型（ME-2）对其中复杂的有机物进行来源解析.观测期间,有机物、硝酸盐、硫酸盐、铵盐、氯化物对NR-PM₁的贡献分别为42%,28%,15%,13%和2%.有机物解析出6类有机气溶胶：烃类有机气溶胶（HOA）、烹饪类有机气溶胶（COA）、生物质燃烧有机气溶胶（BBOA）、高氧化有机气溶胶（MO-OOA）、低氧化有机气溶胶（LO-OOA）、液相反应生成氧化有机气溶胶（aq-OOA）,平均浓度分别占总有机气溶胶的18%,14%,19%,19%,11%和19%.通过不同污染事件的对比结果表明,本次观测期间二次气溶胶在污染时期占比会明显上升并且液相反应对二次组分的形成有显著的促进作用.     

再生铜冶炼过程中重金属排放特征和控制

再生铜冶炼是重要的重金属排放源,为掌握再生铜冶炼过程中重金属的排放特征和控制效果,通过固定源等速采样装置采集不同冶炼阶段的烟气样品,利用电感耦合等离子体质谱仪测定烟气和飞灰中重金属的浓度,并估算重金属的排放因子.结果表明,在冷却阶段烟气中重金属和颗粒物的浓度较高,经过布袋除尘器和吸附塔等污染控制装置后,重金属和颗粒物被协同脱除,脱除效率达80%～99%.排放烟气中重金属的浓度在阳极炉不同工艺段中的排序为：加料熔融段>氧化段≈还原段,且As、 Pb、 Cr、 Sn、 Sb和Cd的平均排放因子分别为2.6×10³、2.4×10³、2.7×10³、5.6×10²、34.1和9.8 mg·t^-1,烟气中重金属和颗粒物的浓度均满足行业排放标准.飞灰中Cu和Zn的浓度较高,具有回收利用价值.     

我国黑土地农田土壤除草剂残留特征研究及展望

粮食安全是“国之大者”.东北黑土地作为我国重要的粮仓,是保障国家粮食安全的“压舱石”.但黑土地农田除草剂的长期高强度施用,导致除草剂在土壤中积累和迁移,影响土壤质量、作物产量和品质,阻碍黑土地可持续利用和农业可持续发展.解决黑土地农田除草剂残留问题,既要从源头管控除草剂的施用,也要掌握除草剂的残留特征、时空演变和驱动因素,才能做到科学防控、精准施策.系统总结了我国黑土地农田除草剂的施用状况和存在的问题,全面梳理了除草剂的残留现状,指出了当前在黑土地农田除草剂残留特征、空间分布和污染诊断等研究上的不足,提出了我国黑土地农田除草剂残留诊断与风险管理研究思路与重点方向,为保障我国黑土地农田土壤健康、粮食安全和生态系统安全提供科技支撑.     

复合污染条件下人为源VOCs的SOA生成研究进展

大气细颗粒物(PM_2.5)仍是我国空气质量持续改善的重大挑战.近年来,二次有机气溶胶(SOA)对PM_2.5的贡献日益凸显.因此,深入认识复合污染条件下SOA生成机制和影响因素可以为进一步降低PM_2.5提供重要理论依据.实验室模拟是深入认识SOA生成机制的关键途径,也是模式模拟参数化方案的可靠来源之一.主要综述了我国多污染物共存条件下典型人为源挥发性有机物(VOCs)的SOA生成研究进展,包括汽油蒸气VOCs、生物质燃烧VOCs和含氧VOCs形成SOA过程中,前体物浓度、芳香烃含量、无机气体、种子气溶胶和相对湿度(RH)等不同因素对SOA生成的影响;阐述了实际大气VOCs的SOA生成潜势及其影响因素,最后提出了目前在SOA机制研究方面存在的关键科学问题,并对未来的研究方向进行了展望.     

Pulmonary stenosis and reactive right ventricular hypertrophy in the recipient fetus as a consequence of twin-to-twin transfusion

The present study describes an association between adverse outcome in the twin-to-twin transfusion syndrome (TTTS) and pulmonary stenosis or reactive right ventricular hypertrophy. Six discordant monozygotic twin pregnancies with TTTS are described. Ventricular hypertrophy and atrioventricular valvular regurgitation occurred in all the recipient twins with pulmonary valvular stenosis in three cases and infundibular stenosis in one case. The recipient twin in one pair and both twins in another pregnancy died as a consequence of immaturity but the remaining twins all survived. Surgical intervention was required in one baby for valvular pulmonary stenosis. Our observations suggest that elevated blood pressure in the transfusion recipient may play an important role in pathogenesis. We hypothesise that both pulmonary stenosis and right chamber hypertrophy are secondary to hemodynamic changes. Although we have found valvular pulmonary stenosis in three recipients and infundibular stenosis in only one, this (obstruction to outflow) could be due to right chamber hypertrophy. Copyright © 2001 John Wiley & Sons, Ltd.     

Residual risk for cytogenetic abnormalities after prenatal diagnosis by interphase fluorescence in situ hybridization (FISH)

Results from conventional cytogenetic studies on 21 609 amniotic fluid specimens were analyzed retrospectively to determine the residual risk for a cytogenetic abnormality if interphase FISH, capable of only detecting aneuploidy for chromosomes 13, 18, 21, X and Y, was performed and did not reveal an abnormality. Detection rates (the probability of detecting a cytogenetic abnormality when an abnormality is present) and residual risks (the likelihood of a cytogenetic abnormality, in view of normal interphase FISH results) were calculated for the four major clinical indications for prenatal diagnosis (advanced maternal age, abnormal maternal serum screen indicating increased risk for trisomy 18 or trisomy 21, abnormal maternal serum screen indicating increased risk for neural tube defects and ultrasound abnormality). Differences in detection rates were observed to depend on clinical indication and presence or absence of ultrasound abnormalities. The detection rate ranged from 18.2 to 82.6% depending on the clinical indication. The detection rates of abnormalities significant to the pregnancy being evaluated (i.e. abnormalities excluding familial balanced rearrangements and familial markers) were between 28.6 and 86.4%. The presence of ultrasound abnormalities increased the detection rate from 72.2 to 92.5% for advanced maternal age and from 78.6 to 91.3% for abnormal maternal serum screen, indicating increased risk for trisomy 18 or trisomy 21. With regard to residual risk, the risk for a clinically significant abnormality decreased from 0.9–10.1%, prior to the interphase FISH assay, to a residual risk of 0.6–1.5% following a normal interphase FISH result in the 4 groups studied. Providing patients with detection rates and residual risks, most relevant to their situation (clinical indication and presence or absence of ultrasound abnormality) during counseling, could help them better understand the advantages and limitations of interphase FISH in their prenatal diagnostic evaluation. Copyright © 2003 John Wiley & Sons, Ltd.     

Bacterial colonization of the phyllosphere of nineteen plant species and antimicrobial activity of their leaf secondary metabolites against leaf associated bacteria

Summary. The scope of this work was to examine whether leaf constitutive secondary metabolites play a role in determining bacterial colonization of the phyllosphere. To this aim, we surveyed nineteen native or cultivated plant species that share a common bacterial pool in a North Mediterranean area, and estimated the size of total and ice nucleation active (INA) bacterial populations on their leaves. Large differences in the colonization of their phyllosphere were found; the population size of epiphytic bacteria ranged from 7.5 × 10² to 1 × 10⁶ CFU/g fresh weight, in eucalypt and celery, respectively. Species native in Mediterranean-type climate areas, particularly those belonging to the group of aromatic plants, are characterized by scarce presence of INA bacteria. The antibacterial activity of essential oils, surface phenolics and leaf tissue extracts was also estimated against the INA strains P. syringae and E. herbicola, isolated from two of these plant species. E. herbicola proved more sensitive than P. syringae. Of the species examined, oregano [Origanum vulgare L. subsp. hirtum (Link.) Ietswaart], an aromatic plant, had the highest antimicrobial activity, whereas six species showed no activity at all. Further experiments were performed with oregano and bean (Phaseolus vulgaris L.) that represent two extremes in their secondary metabolite content. Both plants were inoculated with P. syringae. By the end of incubation, the bacterial population on bean plants was about 100 times higher than that on oregano leaves. Scanning electron micrographs showed that bacterial growth on oregano leaves was confined to sites away from glandular hairs. Results from the bacterial colonization survey together with those from the toxicity tests showed that all species rich in antibacterial secondary metabolites harbored low leaf bacterial populations. These results provide substantial evidence that leaf secondary metabolites function as constitutive defense chemicals against microbial invasions. However, the fact that species with non- or moderately active leaf secondary metabolites are not always highly colonized suggests mediation of other unknown factors, the contribution of which requires further investigation.     

真空吸尘系统应用于散货码头的积尘清扫

描述了散货码头粉尘污染现状,分析比较了几种常用的积尘清扫方法。为了有效清扫散货码头的积尘,提出采用集中式真空吸尘系统。文章从系统形式、水力计算方法和工程实例等方面简单介绍了集中式真空吸尘系统。印尼Paiton燃煤电厂码头工程设计采用了集中式真空吸尘系统进行积尘清扫,工程建成投产一年多来,积尘清扫效果明显,有效地降低了粉尘污染。实例说明,真空吸尘是解决散货码头积尘清扫问题较为有效的方式。     

植物释放挥发性有机物(BVOC)向二次有机气溶胶(SOA)转化机制研究

利用自制玻璃生态罩,研究植物挥发性有机物（BVOC）的释放机制.在紫外光诱导条件下,BVOC经历一系列的光氧化反应,最终产生了二次有机气溶胶（SOA）.运用固相微萃取（SPME）和气相色谱-质谱联用（GC-MS）技术,对目标植物（驱蚊草）释放出的BVOC进行采样分析,共检测出7种主要化合物,其中主要为单萜类、倍半萜类、醇类和酮类物质.研究发现,在紫外光的照射下,这些BVOC可以发生光氧化反应转化为SOA.利用串联差分淌度分析仪（TDMA）测定SOA的粒径分布和SOA颗粒物的吸湿性.结果表明粒径范围大致是50～320 nm,吸湿性研究发现这些SOA具有吸湿性,生长因子可以从1.05增长到1.11.