Interaction of diuron to human serum albumin: Insights from spectroscopic and molecular docking studies

This investigation was undertaken to determine the interaction of diuron with human serum albumin (HSA) was studied by monitoring the spectral behavior of diuron-HSA system. The fluorescence of HSA at 340 nm excited at 230 nm was obviously quenched by diuron due to dynamic collision and the quenching constant was of the order of 10⁴ L mol^?1 at 310 K. However, no fluorescence quenching was observed when excited at 280 nm. Thermodynamic investigations revealed that the combination between diuron and HSA was entropy driven by predominantly hydrophobic interactions. The binding of diuron induced the drastic reduction in α-helix conformation and the significant enhancement in β-turn conformation of HSA. In addition, both sites marker competition study and molecular modeling simulation evidenced the binding of diuron to HSA primarily took place in subdomain IIIA (Sudlow's site II).     

Production of anti-amoxicillin ScFv antibody and simulation studying its molecular recognition mechanism for penicillins

The molecular recognition mechanism of an antibody for its hapten is very interesting. The objective of this research was to study the intermolecular interactions of an anti-amoxicillin antibody with penicillin drugs. The single chain variable fragment (ScFv) antibody was generated from a hybridoma cell strain excreting the monoclonal antibody for amoxicillin. The recombinant ScFv antibody showed similar recognition ability for penicillins to its parental monoclonal antibody: simultaneous recognizing 11 penicillins with cross-reactivities of 18–107%. The three-dimensional structure of the ScFv antibody was simulated by using homology modeling, and its intermolecular interactions with 11 penicillins were studied by using molecular docking. Results showed that three CDRs are involved in antibody recognition; CDR L3 Arg 100, CDR H3 Tyr226, and CDR H3 Arg 228 were the key contact amino acid residues; hydrogen bonding was the main antibody–drug intermolecular force; and the core structure of penicillin drugs was the main antibody binding position. These results could explain the recognition mechanism of anti-amoxicillin antibody for amoxicillin and its analogs. This is the first study reporting the production of ScFv antibody for penicillins and stimulation studying its recognition mechanism.     

低分子量壳聚糖Nd3＋配合物的合成及抑菌性研究

通过将高分子量壳聚糖经双氧水氧化降解制得低分子量壳聚糖,再与Nd3＋配位制得低分子量壳聚糖Nd3＋配合物,通过IR,UV,TG—TDA和GPC分析对L—CTS的分子量及L—CTS—Nd的结构进行了表征,考察了对金黄色葡萄球菌和大肠杆菌的抑菌性能。结果表明,低分子量壳聚糖与Na3＋形成了稳定的配合物,对金黄色葡萄球菌和大肠杆菌均有良好的抑菌效果。     

火电厂烟气脱硫塔气体分布装置设计

喷淋塔扣烟气循环流化床脱硫塔被广泛应用于火电厂烟气脱硫工程中,介绍了两种脱硫塔的气体分布装置及其工艺设计,为脱硫设计提供参考。     

低分子量有机酸对氧化亚铁硫杆菌影响

氧化哑铁硫杆菌生物淋滤修复重金属污染土壤研究报道很少,因为该菌对低分子量有机酸敏感.研究 6 种低分子量有机酸(甲酸、乙酸、丙酸、草酸、苹果酸和柠檬酸)对嗜酸性氧化哑铁硫杆菌 R2 氧化 Fe2 的影响,且利用高效液相色谱法测定沈阳冶炼厂和张士灌区重金属污染土壤中低分子量有机酸的浓度.结果表明,6 种有机酸对 R2 氧化能力均具有抑制作用,且抑制顺序为:甲酸乙酸丙酸草酸苹果酸柠檬酸.其中 R2 对甲酸最敏感,甲酸浓度为0.064 mmol/L时,抑制率达到 60%;浓度为 0.254 mmol/L时,R2 氧化Fe2 的能力完全被抑制.液相色谱分析可知,冶炼厂和张士灌区土壤中有机酸的浓度很低,其中草酸含量最高,分别为 0.04和 0.149 mmol/L.尽管氧化亚铁硫杆菌对低分子量有机酸很敏感,但是试验土壤中低分子量有机酸的浓度远远低于硫杆菌的耐受限度.因此,分离菌株 R2 有望应用于重金属污染土壤的修复.     

CuAPO-5分子筛催化氧化水溶液中苯酚的性能

以水热晶化法合成了铜磷铝分子筛CuAPO-5,并用XRD、SEM,FT-IR,UV-Vis等对样品进行了表征,结果表明Cu²⁺进入到了AlPO₄-5分子筛骨架中。研究了以CuAPO-5为催化剂, H₂O₂为氧化剂对水溶液中苯酚的催化氧化性能。在苯酚初始浓度200 mg/L 、H₂O₂添加量1 200 mg/L、pH值5.0、处理温度80 ℃时,处理240 min时苯酚去除率达到100％,TOC去除率达81.76％,析出到溶液中Cu²⁺浓度仅为0.527 mg/L。温度从40 ℃上升到80 ℃时,苯酚的去除率及TOC去除率明显增大,表明温度对催化剂的活性影响显著,相比于均相催化剂骨架Cu催化过氧化氢分解需要更多的能量。重复性实验表明,催化剂性能稳定。     

北运河上覆水DOM分子组成和结构特征

利用高分辨傅里叶变换离子回旋共振质谱技术(FT-ICR-MS)及分析手段综合表征了北运河上覆水中DOM分子组成和结构特征,揭示了DOM分子组成的迁移转化规律,并评估了DOM分子组成的潜在环境影响.结果表明:北运河上覆水DOM分子化合物主要由木质素(63.19%)和蛋白质(12.96%)组成.上覆水中稳定DOM分子公式主要由难降解木质素和不断循环且再生的基本代谢物及分泌物组成,独特DOM分子公式的多样性与人为活动强度有关,优先被转化或降解的相同DOM分子公式主要为携带高化学活性羧基和羟基的木质素和不稳定的脂质、蛋白质和碳水化合物.北运河具有外源废水输入量高的特点,致使上覆水具有大量不稳定DOM化合物,增加了河流富营养化的潜在风险.     

石墨烯复合物在痕量气体分子检测中的应用

综述了石墨烯复合物的种类、性能与制备方法,以及在痕量气体分子检测中的应用。石墨烯具有大的比表面积和独特的电学性质,对一些气体分子有很强的吸附能力,制作的传感器用于气体分子检测时灵敏度较高,但选择性较差。氧化石墨烯巨大的比表面积和表面丰富的官能团赋予的优异的复合性能,可提高传感器的检测灵敏度和选择性。     

碱性过硫酸钾氧化-气相分子吸收光谱法测定水中总氮

采用碱性过硫酸钾氧化-气相分子吸收光谱法测定水中总氮,用螺纹盖聚四氟乙烯消化管代替比色管,称重法校正体积,加大NaOH用量,讨论了干扰及消除办法。方法在0μg~20.0μg范围内线性良好,检出限为0.016 mg/L,标准溶液平行测定的RSD≤1.5%,实际水样加标回收率为99.2%~102%,测量结果的扩展不确定度为3.3%。     

城市污水二级出水中溶解性有机物特性分析

分别采用凝胶色谱、亲疏水性组分分离、荧光色谱等方法,研究了城市污水处理厂二级出水中溶解性有机物的分子量分布、亲疏水组分含量以及荧光光谱特性。结果表明,二级出水中疏水性组分较亲水性组分多,疏水性组分约占总有机物的64.3%,而亲水性组分占35.7%左右;二级出水及其不同亲/疏水组分中溶解性有机物分子量分布基本集中在4.5 kDa以下,其中弱疏水性组分和亲水性组分中主要为分子量小于1.5 kDa的有机物;二级出水溶解性有机物中含有腐殖酸类、富里酸类以及蛋白质类物质,其中含量以腐殖酸类为主。