自催化法合成聚天冬氨酸

以马来酸酐和乙酸铵为原料，在微波条件下用自催化法合成了聚天冬氨酸（PASP）。通过正交实验确定了最佳合成条件：n（乙酸铵）：n（马来酸酐）=1．2，微波功率为1200W，反应时间为10min。在最佳合成条件下，PASP的收率为91．6％，PASP的黏均相对分子质量约为1．5×10^4。经红外光谱表征和核磁共振氢谱测试结果表明，PASP的各种主要官能团表现明显。当Ca^2＋质量浓度为250mg／L、PASP加入量为3mg／L时，PASP的阻垢率达到95％，表明PASP具有较好的阻垢性能。     

氯苯嘧啶醇在水体中的光解机制研究

以太阳光为实验光源研究了氯苯嘧啶醇在水溶液中的光解,考察了pH、水体类型、溶解氧及卤素离子等对其光解的影响.结果表明,氯苯嘧啶醇在水溶液中的光解符合一级动力学方程,在不同水体中氯苯嘧啶醇光解的速率大小顺序为:重蒸水>水库水>湖水>池塘水;氯苯嘧啶醇光解的半衰期随着溶液pH的增大而延长,当pH为5、7、9、11时光解半衰期分别为5.00、6.86、7.45、7.53 h;3种卤素离子对氯苯嘧啶醇光解有很大的影响,均表现出强的猝灭作用,3种离子的猝灭能力的大小顺序为Ⅰ->Br->Cl-;溶解氧和三重态光猝灭剂山梨酸均对氯苯嘧啶醇在水中的光解没有影响,而三重态光敏剂丙酮则对其光解有较强的猝灭作用,表明氯苯嘧啶醇在水中的光解主要以直接光解为主,光解过程不经历三重态.     

Implications of urine-to-feces ratio in the thermophilic anaerobic digestion of swine waste.

Thermophilic anaerobic digestion of swine manure represents a potential waste treatment technology to address environmental concerns, such as odor emissions and removal of pathogenic microorganisms. However, there are concerns relative to the stability of this process when swine manure is the sole substrate. In this study, the potential of biogas production from swine manure as the sole substrate under thermophilic (50 degrees C) conditions was investigated in the laboratory, to determine whether separation of urine and feces as part of the waste collection process would benefit anaerobic digestion. Effluent from a continuously stirred tank reactor was used as the inoculum for batch tests, in which the substrate contained three different concentrations of urine (urine-free, as-excreted urine-to-feces ratio and double the as-excreted urine-to-feces ratio). Inocula were acclimated to these same urine-to-feces ratios to determine methane production. Results show that both urine-free and as-excreted substrates were not inhibitory to anaerobic inocula. Anaerobic microorganisms can be readily acclimated to substrate with double the as-excreted urine concentration, which contained nitrogen concentrations up to 7.20 g/L. Cumulative methane production reached similar levels in the batch tests, regardless of the substrate urine concentration.     

Sorption of the veterinary antimicrobials sulfadimethoxine and ormetoprim in soil

Currently, limited research on the fate of antimicrobials in the environment exists, once they are discharged in human and animal wastes. Sorption of two antimicrobials, sulfadimethoxine (SDM) and ormetoprim (OMP), was investigated in two soils and sand using a series of batch experiments. Because OMP and SDM are often administered in combination, their sorption was also investigated in combination as co-solutes. The rate of SDM and OMP sorption was rapid over the first few hours of the experiments, which then slowed considerably after 16 to 68 h. OMP sorption was enhanced at high concentrations when in combination with SDM, with linear sorption coefficients ranging from 1.3 to 58.3 L.kg(-1) in the single solute experiments and 4.96 to 89.7 L.kg(-1) in the co-solute experiments. Sorption of OMP as a single solute seems to provide a better fit with the Freundlich equation, which became more linear (n approached 1) when SDM was present. Overall, SDM sorbed less than OMP in the two soils and sand. SDM linear sorption coefficients ranged from 0.4 to 25.8 L.kg(-1) as a single solute and 2.5 to 22.1 L.kg(-1) as a co-solute. Sorption of SDM becomes more nonlinear (n < 1) when SDM is present in combination with OMP. Overall, sorption of both antimicrobials increased in the selected soils and sand as the organic matter, clay content, and cation exchange capacity increased. These experiments indicate relatively low sorption of SDM and OMP in natural soils, making them a potential threat to surface and ground water.     

固定化混合菌修复油污染地表水的研究

从辽河油田受石油污染的河床底泥中筛选出一株芽孢杆菌(Bacillus sp.)和一株黄杆菌(Flavobacterium sp.)，采用二次交联化学方法对2株细菌单独及混合固定，分别进行了不同接种量的固定化细菌对油的降解，以及固定化混合菌对环境的耐受性和在自然地表水中对油的降解进行研究，结果表明，在相同时间内固定化混合菌对油的降解效果明显优于固定化单株菌，而且都优于游离菌。固定化混合菌pH在6～10、温度在20～40℃范围内能保持较好的活性。在120 h时，固定化混合菌对自然地表水中油的降解率达94.5%,对地表水中COD的去除率达89.6%。扫描电子显微镜分析显示，固定化载体的微观结构适合细菌的生长，固定化混合菌在载体内部形成高密度的菌群。以上的研究为固定化微生物应用于油污染地表水的生物修复提供了一定的理论基础。     

卫星遥感技术在管理长江流域水资源方面的应用研究

详细讨论了卫星遥感技术在长江流域水资源管理方面的应用问题，提出了两种实用的方法：①卫星遥感技术在灌溉水资源管理方面的应用；②长江流域地下水、地表水资源估算。进一步分析了两种方法的特点，介绍了卫星遥感技术的优点及用途，建议在长江流域水资源管理中加以利用。     

长江中游平原湖区农业开发地域分工与农产品专业化生产研究

农业生产地域分工与农产品专业化生产是使农业从自然经济阶段向以市场为导向的商品农产品生产转变的一个标志。本文在分析该区农业布局现状及其存在问题的基础上，提出了农业总体布局的设想与不同类型地域农业开发的主攻方向与对策，并对市场经济体制下粮食、棉花、猪、禽、水产品等农产品生产基地的地域选择、建设规模与技术措施等进行了探讨。     

Dandy – Walker syndrome and corpus callosum agenesis in 5p deletion

5p deletion syndrome commonly known as cri du chat is well described in affected neonates with catlike cry and hypotonia. Karyotyping will usually show a deletion of the short arm of one chromosome 5 with variable breakpoints. Only a few cases have been reported prenatally, and the fetal form of the syndrome has not been clearly individualised. We report a new case of 5p deletion syndrome diagnosed prenatally in association with Dandy–Walker syndrome and agenesis of the corpus callosum. Other brain anomalies have been reported previously, but this unusual association suggests the use of a specific probe in the investigation of these malformations. Copyright © 2005 John Wiley & Sons, Ltd.