新型荧光分子印迹膜特异性识别和检测目标蛋白质

制备了一种新型荧光分子印迹膜(L-半胱氨酸修饰的量子点嵌入的分子印迹膜(QDs@MIM)),并将其作为荧光人工受体用于目标蛋白质(溶菌酶)的特异性识别和检测。QDs@MIM以溶菌酶为模板分子、丙烯酰胺为功能单体、L-半胱氨酸修饰的量子点为辅助单体、N,N′-亚甲基双丙烯酰胺为交联剂,在预硅烷化的玻璃板上制备而成。在最佳条件下,QDs@MIM对溶菌酶检测的线性范围为0.1~1.0μmol/L,吸附平衡时间为4 min,选择性因子为6.2。该方法操作简单、吸附平衡时间短、选择性高,具备作为生物传感器快速分析样品中目标蛋白质的潜力。     

虾肝肠胞虫感染病理特征、18S rRNA基因序列及系统进化树分析

为调查浙江省部分地区虾肝肠胞虫(Enterocytozoon hepatopenaei,EHP)暴发来源及与其他宿主来源的微孢子虫进化关系,本研究利用形态学特征和分子鉴定,尝试对引起浙江多地凡纳对虾生长缓慢综合征的病原进行探究.同时基于18S rRNA基因序列分析该病原与其他地区及其他宿主来源微孢子虫的进化关系.结果显...     

Uniform persistence and periodic solutions for Kolmogorov system with delays

We consider the general delayed Kolmogorov-type predator–prey system. The uniform persistence and the existence of positive periodic solutions will be studied by using new approaches. Our results improve some in the literatures. Some examples are given to illustrate the obtained results.     

3-羟基克拉霉素和2''-乙酰基-3-氧代克拉霉素的合成与晶体结构

克拉霉素在不同条件下水解,分别生成3-羟基克拉霉素(2)和3-羟基-8,9,10,11-二脱水-9,12-半缩酮克拉霉素(3),用乙酸酐保护2的C(2')-OH得到2'-乙酰基-3-羟基克拉霉素(4),用Ⅳ-氯代琥珀酰亚胺(NCS)氧化4的C(3)-OH合成了2'-乙酰基-3-氧代克拉霉素(5),采用MS,IR,1H NMR,13C NMR等对这些化合物进行了表征.用X射线单晶衍射法测定了化合物2和5的晶体结构,其均属于正交晶系,P212121空间群.化合物2的晶胞参数a=1.3657(3)nm,6=1.4783(3)nm,c=1.6510(3)nm,Z=4,V=3.3332(12)am3,Dc=1.175 g/cm3,F(000)=1288,μ=0.087mm-1;化合物5的晶胞参数a=1.5124(3)nm,b=1.5247(3)nm,c=1.5288(3)nm,Z=4,V=3.5254(12)nm3,Dc=1.187g/cm3,F(000)=1368.0,μ=0.088 mm-1.     

Semi-implicit Skew Upwind Method for problems in environmental hydraulics

A new computational method is presented for reducing numerical diffusion in environmental fluid problems. This method, which is referred to as the Semi-Implicit Skew Upwind Method (SISUM), is a robust solution procedure for the conditional convergence of the discretized transport equations. The method retains the advantage of the low numerical diffusion of the conventional skew upwind schemes but does not suffer from over- or under-shooting often found in these methods due to the improved interpolation schemes. The effectiveness of SISUM is demonstrated in several examples. The comparison of the results of a hybrid scheme and SISUM with field observations of convection-dominated pollutant transport in strongly curvilinear river flow shows that SISUM successfully eliminates the high numerical diffusion produced by the hybrid scheme. The robustness of the method was tested by solving the hydrodynamics of a circular clarifier model with a large density gravity source term in the vertical-momentum equation.     

双环和多环四唑含能化合物的合成研究进展

综述了近年来双环和多环四唑含能化合物的合成研究进展,包括偶氮四唑、联四唑、双环四唑胺、肼基四唑、硝胺基四唑、硝基四唑、烷基相连的双环四唑、多环四唑等,结合化合物的表征,对双环和多环四唑含能化合物的性质做了阐述,对双环和多环四唑含能化合物的发展做了展望.     

A new strategy for designing non-C2-symmetric monometallic bifunctional catalysts and their application in enantioselective cyanation of aldehydes

A monometallic bifunctional catalyst, in which only one imidazolyl moiety is directly attached at the 3-position of a binaphthol moiety, has been developed. The ligand (R)-1, which lacks C2-symmetry and flexible linkers, in combination with Ti(OiPr)4, has been demonstrated to promote the enantioselective cyanation of aldehydes with trimethylsilylcyanide (TMSCN), giving excellent enantioselectivities of up to 98 % ee and high yields of up to 99 %. The use of this bifunctional catalytic system obviates the need for additives and is extremely simple as the reagents are added in one portion at the beginning of the reaction. The protocol has been found to tolerate a relatively wide range of aldehydes when 10 mol % of the (R)-1/Ti(OiPr)4 complex is deployed in CH2Cl2 at -40 degrees C, the conditions which proved most practical and effective. The asymmetric cyanations also proceeded with lower catalyst loadings (5 mol %, or even 2 mol %), still giving satisfactory enantiomeric excesses and yields. Interestingly, the use of freshly distilled TMSCN dried over CaH2 gave a low enantioselectivity and only a moderate yield of the adduct as compared with direct use of the commercial reagent. The results of 13C NMR spectroscopic studies implicate HCN as the actual reactive nucleophile.     

结晶型聚合物注塑过程冷却模型的数值模拟

对HDPE平板状注塑件的冷却过程进行了数值模拟 .基于小分子结晶性物质的冷却模型 ,建立了固相、液相及固液相界面的控制方程 ,方程中引入热焓E和参数T 后 ,将带耦合条件的热传导方程转变为非线性抛物型方程 ,按控制容积法将其离散后 ,用数学软件Matlab获得了PE的三维温度场 ,这为探讨带相转变的热传导问题提供了一种有效的数值方法 .通过对制件芯层温度变化的模拟值与实验值的比较 ,比较了不同相变温度下理论结果的准确性 ,结果表明 ,在引入一定过冷度后 ,将相变温度定义在低于平衡熔点以下时 ,该方法的模拟值具有更好的准确性 .同时 ,模型分析了不同工艺条件对制件芯层冷却过程的影响 ,通过相变平台出现的先后以及终止时间的不同 ,说明充模温度主要影响熔体阶段的冷却以及相变出现的先后 ,而模具温度主要影响固体阶段的冷却以及相变平台终止的先后 .     

Palladium supported on metal–organic framework as a catalyst for the hydrogenation of nitroarenes under mild conditions

Sustainable development demands an environmentally friendly and efficient method for the hydrogenation of organic molecules, including the hydrogenation of functionalized nitroarenes. In this study, a highly active and selective metal–organic framework-supported palladium catalyst was prepared for the catalytic hydrogenation of nitroarenes. High selectivity (>99%) and excellent yield (98%) of aniline were realized after 2 hours in ethanol under hydrogen (1 atm) at room temperature. The reductions were successfully carried out in the presence of a wide range of other reducible functional groups. More importantly, the catalyst was very stable without the loss of its catalytic activity after five cycles.     

MIL-101负载Ni@Pd核壳纳米粒子催化芳香硝基类化合物加氢

金属有机骨架(MOFs)材料是一种新型的沸石类多孔材料,是由金属离子和有机配体通过配位键键合而成的拓扑结构.相比其他多孔材料,MOFs拥有更高的比表面积、孔隙率以及结构可调控性.在催化方面,MOFs复合材料在多相催化领域已经引起了广泛的研究兴趣.贵金属纳米颗粒是一种在化学、化工、生物和医学等许多领域有着广泛应用的高性能材料.但是,催化反应往往都是发生在纳米颗粒的表面,而位于颗粒内部的金属没能得到利用;从原子经济性的角度来看,以廉价金属作核、贵金属作壳的双金属纳米粒子能有效解决这个问题,而且还能利用双金属之间的协调作用.目前文献中也已经报道了多种非贵金属和贵金属组成的核壳双金属纳米粒子,都展现出了比单纯贵金属更好的催化活性.芳香胺类化合物是一种在工业上非常重要的有机中间体,广泛应用于农药、药物、染料和色素等等.目前,商业化生产的芳香胺化合物都是通过计量的还原剂,如连二硫酸钠、硼氢化钠、水合肼和氨水中的铁、锡、锌等非催化还原相应的芳硝基化合物得到,这样往往会带来严重的环境污染问题.而通过多相催化加氢还原方法来制备芳香胺化合物,不仅能高效催化芳硝基化合物加氢,而且催化剂可以回收利用,大大降低反应对环境的污染.本文综合贵金属原子经济观点和芳硝基类化合物加氢反应催化剂设计,在油胺和三正辛基膦中通过热还原二价的镍和钯,制备出以Ni为核Pd为壳的双金属纳米粒子.通过透射电镜观察,镍钯核壳纳米粒子的粒径约为8-9 nm.选用具有高比表面积和高稳定性的金属有机骨架材料MIL-101作为载体,通过浸渍法首次将镍钯核壳纳米粒子负载在MIL-101上制备出不同Ni:Pd比的Ni@Pd/MIL-101复合材料.利用X射线粉末衍射(XRD)、N2吸附-脱附、红外光谱、透射电子显微镜和X射线能谱对复合材料结构进行了表征.从XRD谱图能看出负载纳米粒子后的MIL-101材料结构依然保持完整,表明催化剂制备过程不会破坏载体结构.红外光谱测试结果表明,负载了镍钯纳米粒子的Ni@Pd/MIL-101复合材料中含有两种C-H键伸缩振动2852和2926 cm-1处两个特征峰,分别对应于-CH2-和-CH3中C-H键的特征吸收峰,可能是残留的油胺,也可能是三正辛基膦在与镍和钯形成配合物时的残留.X射线能谱测试发现,N元素在负载后已不存在,而P元素依旧存在,结合红外光谱可以确认,纳米粒子在负载前后三正辛基膦依然与纳米粒子稳定络合,进而可被MIL-101上未饱和的Cr固定.通过透射电镜可以观察到镍钯核壳纳米粒子高度分散在载体上.将Ni@Pd/MIL-101材料应用于硝基苯催化加氢反应.在30℃,0.1 MPa H2条件下,0.26％ Ni@0.46％Pd/MIL-101催化剂具有最高的加氢活性,其转换频率(TOF)值最高可达375 h-1,是单金属负载钯催化剂的近2倍,展示出非贵金属替代部分贵金属的可行性.在循环使用方面,重复使用5次后的Ni@Pd/MIL-101催化剂依然保持较高的催化活性和选择性.同时考察了底物的兼容性,该催化体系对多种不同基团(包括不饱和基团)取代的硝基苯化合物的催化加氢,大都表现出很高的催化活性和选择性,TOF值最高可达495 h-1.