995 resultados para 196-1173B
Resumo:
The porosity and the hydrophobicity of membranes are two essential requirements for membrane distillation (MD) of aqueous solutions. So far, the hydrophobic porous membranes used in MD studies have been prepared from hydrophobic materials. In this work, hydrophilic cellulose acetate and cellulose nitrate membranes were modified into hydrophobic membranes by radiation grafting polymerization and plasma polymerization, and used in MD studies successfully. The results indicated that modified membranes with good performance in MD can be obtained if the modifying conditions are controlled appropriately. Especially plasma polymerization, in which many particular kinds of monomer could be polymerized onto the surface of porous materials, has become an efficient method to prepare hydrophobic porous membrane with high performance from hydrophilic membranes. It will stimulate the development and practical application of MD.
Resumo:
Thermogravimetric and derivative thermogravimetric investigations for three kinds of bioinorganic complexes of europium with N-acetyl-DL-alanine, N-acetyl-DL-valine and DL-alanyl-DL-alanine have been performed. It was found that the water molecules in these solid state complexes are not directly coordinated to the europium ion and that there may be three or four steps in the thermal decomposition process of these complexes after dehydration. The possible thermal decomposition reactions of these bioinorganic complexes have been suggested and discussed.
Resumo:
制备了三—[4—(2,4—二特戊基苯氧基)]—4—对羧基苯氧基酞菁铜(简写为asyCuPc)LB膜,对比紫外可见光谱及LB膜的偏振紫外可见光谱探讨了该化合物的不同聚集态,结果表明该酞菁铜分子大环平面在LB膜中为倾斜取向.
Resumo:
尼龙1010的晶体结构属三斜晶系.作者最近导出了X射线衍射法(WAXD)测定尼龙1010结晶度的公式,进而考查了等温结晶时结晶温度T_C对结晶度X_C、晶粒尺寸L_(100)和氢键面相对衍射强度R的影响.发现X_C和L_(100)均随T_C升高而增大,达196℃后又减小;而R与T_C的关系则相反,呈线性降低.结晶速率快有利于分子链在垂直于氢键面的(100)晶面生长,但R值却降低了.本文利用WAXD考查了尼龙1010不同骤冷退火条件样品的晶体结构.
Resumo:
以Nd(naph)_3-Al(i-Bu)_3-Al_2Et_3Cl_3为催化剂,在-10~5℃下对异戊二烯(Ip)本体聚合的动力学进行了初步研究。发现单体转化率小于5%时,体系呈非稳态聚合;单体转化率大于50%时聚合受扩散控制;体系处于两者间则为稳态聚合。本体聚合的稳态聚合反应速率方程式为:R_p=K_p[Ln]~(196)M_0,计算出Ip本体聚合的表现活化能为69.9kJ/mol。
Resumo:
Reaction of lanthanoid trichloride with two equivalents of sodium t-butylcyclopentadienide in tetrahydrofuran affords bis(t-butylcyclopentadienyl)lanthanoid chloride complexes (t-BuCp)2LnCl. nTHF (Ln = Pr, Nd, n = 2; Ln = Gd, Yb, n = 1). The compound (t-BuCp)2PrCl.2THF (1) crystallizes from THF in monoclinic space group P2(1)/c with unit cell dimensions a = 15.080(3), b = 8.855(2), c = 21.196(5) angstrom, beta = 110.34(2)degrees, V = 2653.9 angstrom-3 and D(calcd) = 1.41 g/cm3 for Z = 4. The central metal Pr is coordinated to two t-BuCp ring centroids, one chlorine atom and two THF forming a distorted trigonal bipyramid. The crystal of (t-BuCp)2YbCl.THF (2) belongs to the monoclinic crystal system, space group P2(1)/n with a = 7.726(1), b = 12.554(2), c = 23.200(6) angstrom, beta = 97.77(2)degrees, V = 2229.56 angstrom-3, D(calcd) = 1.50 g/cm3 and Z = 4. The t-BuCp ring centroids, the chlorine atom and the oxygen atom of the THF describe a distorted tetrahedron around the central ion of ytterbium.
Resumo:
The dependence of morphology and properties on film-forming conditions is described for the symmetrically substituted copper tetra-4-(2, 4-di-t-amylphenoxy) phthalocyanine (tapCuPc) Langmuir-Blodgett (LB) films. The effects of LB film-forming conditions (such as the surface pressure, pH value and the concentrations of spreading solutions) on film quality were studied with the help of a UV-visible spectrophotometer and a transmission electron microscope. Transmission electron microscopy photographs of the surface morphology of tapCuPc LB films show that a smooth and homogeneous surface structure can be obtained under optimum film-forming conditions.
Resumo:
The rate constant of very fast chemical reaction generally can be measured by electrochemical methods, but can not by the thin layer electrochemical methods because of the influence of diffusion effect. Long optical path length thin layer cell (LOPTLC) with large ratio of electrode area to solution volume can be used to monitor the fist chemical reaction in situ with high sensitivity and accuracy. It enable the adsorption spectra to be measured without the influence of diffusion effect. In the present paper, a fast chemical reaction of Alizarin Red S (ARS) with its oxidative state has been studied. The reaction equilibrium constant (K) under different potentials can be determined by single step potential-absorption spectra in LOPTLC. An equilibrium constant of 7.94 x 10(5) l.mol(-1) for the chemical reaction has been obtained from the plot of lgK vs. (E - E-1(0)'). Rate constant (k) under different potentials can be measured by single step potential-chronoabsorptiometry. A rate constant of 426.6 l.mol(-1).s(-1) for the chemical reaction has been obtained from the plot of lgK vs. (E - E-1(0)') with (E - E-1(0)') = 0.
Resumo:
本文使用长光程薄层光谱电化学方法监测茜素红S的氧化产物与茜素红S形成分子间氢键的快速化学反应.求出该化学反应的热力学平衡常数为7.94×10~5 l.mol~(-1),动力学反应速率常数为426.6L.mol~(-1)·S~(-1),并从不同角度对实验结果进行讨论。
Resumo:
It is well known that invertebrates are devoid of adaptive immune components and rely primarily on innate immunity to defend against pathogens, but recent studies have demonstrated the existence of enhanced secondary immune protection in some invertebrates. in the present study, the cumulative mortality of scallops received two successive Listonella anguillarum stimulations was recorded, and variations of immune parameters including phagocytosis (phagocytic rate and phagocytic index), phenoloxidase-like enzyme, acid phosphatase and superoxide dismutase activities were also examined. The scallops received a previous short-term L anguillarum stimulation were protected against a long-term stimulation of L. anguillarum. Significantly higher level of phagocytic activities and acid phosphatase activity were observed in the scallops received twice stimulations compared with those only received the secondary stimulation. These results indicated that a short-term immersion with L. anguillarum modulated the scallops' immune system and endowed the scallops with enhanced resistance to the secondary bacterial stimulation: phagocytosis and acid phosphatase were suspected to be involved in the protection. (C) 2008 Elsevier Inc. All rights reserved.
Resumo:
Ferritins are conserved Iron storage proteins that exist in most living organisms and play an essential role in Iron homeostasis. In this study, we reported the identification and analysis a ferritin M subunit, SmFerM, from turbot Scophthalmus maximus. The full length cDNA of SmFerM contains a 5'-untranslated region (UTR) of 232 bp, an open reading frame (ORF) of 531 bp, and a 3'-UTR of 196 bp The ORF encodes a putative protein of 176 amino acids, which shares extensive sequence identities with the M terrains of several fish species. In silico analysis identified in SmFerM both the ferroxidase center of mammalian H ferritins and the iron nucleation site of mammalian L ferritins. Quantitative real time reverse transcriptase-PCR analysis indicated that SmFerM expression was highest in muscle and lowest in heart and responded positively to experimental challenges with bacterial pathogens and poly(I center dot C) Exposure of cultured turbot hepatocytes to treatment of stress inducers (iron, copper, and H2O2) significantly upregulated the expression of SmFerM in a dose dependent manner. Iron chelating analysis showed that recombinant SmFerM purified from Escherichia coli exhibited apparent iron binding activity. These results suggest that SmFerM is a functional M ferritin and is likely to play a role in iron sequestration and protection against oxidative stress and microbial infection (C) 2010 Elsevier Inc All rights reserved
Resumo:
A joint oceanographic cruise between the Institute of Oceanography, Chinese Academy of Science and the Department of Oceanography, Seoul National University was carried out in the Yellow Sea during the summer of 1996 to investigate the concentration and particle-size distribution of suspended particulate matter (SPM). The general trends in the surface and bottom waters show that SPM concentrations and particle sizes decreased seawards in both the western (Chinese) and eastern (Korean) coastal regions of the Yellow Sea. In the bottom waters, SPM concentrations were higher and particle sizes were larger along the eastern coast than along the western coast. We suggest this is due to the resuspension of bottom sediments by strong onshore summer typhoons in the southwestern coastal waters of Korea.
Resumo:
本文利用不同的分子标记方法,分别对牙鲆及大黄鱼不同养殖群体的生长、抗病等经济性状的候选基因进行了序列多态性研究,检测到了几个SNP位点和微卫星的多态性位点,并分析了它们与经济性状之间的相关性;同时,利用微卫星的多态性位点对牙鲆2个养殖群体的遗传变异进行了分析,这些均为海水鱼类遗传育种及标记辅助选育工作提供了基础数据。 在牙鲆胶南养殖群体中,以100个个体为实验材料,根据其生长激素(GH)基因的6个外显子序列设计引物,通过SSCP分析技术显示该群体GH基因的第4外显子存在多态性,检测到2种基因型,AA型和AB型。DNA测序结果表明,AB型在第1763位发生碱基突变,c→t,与AA型同源性达到99%。连锁分析结果表明:这2种基因型的个体在体重和头长上表现出显著的差异,AB型个体的体重和头长都明显大于AA型个体(P<0.05),由此推测等位基因B是一个对牙鲆体重和头长都有利的等位基因;这2种基因型个体之间在其体型性状上也存在显著差异(P<0.05);同时,该多态位点的Hardy-Weinberg平衡性检验结果表明,该群体处于Hardy-Weinberg平衡状态。在牙鲆GH基因第1外显子区域还发现了一个微卫星位点,对该位点进行多态性分析,检测到5种基因型、3种等位基因,one-way ANOVA统计结果显示,基因型AC个体的体重、头长和体高明显大于其它基因型个体(P<0.05),C是一个对体重、头长和体高有利的等位基因。 对2个大黄鱼养殖群体的GH基因进行SSCP分析后发现,浙江群体大黄鱼GH基因在第196位存在1个SNP(g→a)位点,检测到2种基因型,AA和AB。t检验结果表明,AA型个体的体高比AB型个体的高(P≤0.05),但AB型个体在体长/体高上占优势(P≤0.05),提示该突变位点可以作为大黄鱼体型性状的候选标记。福建群体大黄鱼GH基因在第692位有1个SNP位点(t→c),共检测到2种基因型,CC型和CD型,其中,CD基因型个体的体重和全长显著大于CC基因型个体(P≤0.01),提示该位点可以作为大黄鱼体重和头长性状的候选标记。 在牙鲆胶南和日照2个养殖群体中,采用牙鲆GHR基因5’端Promoter区的一个微卫星标记,进行了群体遗传变异的研究,并探索了该基因多态性位点与牙鲆生长性状之间的相关性。结果表明,2个群体在该位点检测到的等位基因数为12和9个,有效等位基因数为6.26和5.04个。两个群体该位点的Hardy-Weinberg遗传偏离指数均为正值,并没有显示出杂合子缺失,但各基因型分布频率都在一定程度上偏离Hardy-Weinberg平衡(P<0.01)。连锁分析发现,在胶南群体中,IM基因型对应的个体在全重、全长、体长、头长、体高和眼径形态学数据中均是最大的,但仅在体重上极其显著的大于全部其它基因型个体;在日照群体中,BC基因型对应的个体在全重、全长、体高、尾柄高、尾柄长和眼径数据中均是最大的;而CJ基因型对应的个体在体长和头长这两组数据中是最大的。由此认为,该位点IM基因型可以作为牙鲆体重性状的潜在标记。 在进行牙鲆抗病性状标记的筛选时,利用迟缓爱德华氏菌(Edwardsiella tarda)LSE40对牙鲆鱼进行攻毒感染实验,得到死亡群体和未死亡群体。选择Toll样受体基因中的TLR2、TLR3和TLR9基因作为候选基因,分别对这3个基因中的部分序列共设计7对引物进行扩增,同时对扩增产物进行RFLP多态性分析,目前只在TLR3基因内检测到一个EcoRI的酶切多态性位点,测序后发现,这是由于在TLR3基因第3806位的EcoRI酶切位点在某些个体中缺失所致。酶切产物共呈现出3种基因型,分别定义为AA,AB和BB。χ2检验证明该多态性位点与牙鲆抗迟缓爱德华氏菌LSE40的能力有一定关系。利用多因素非条件Logistic回归分析对死亡组和存活组牙鲆的各种形态学数据以及不同基因型之间进行了分析,发现体长、头长和体高均具有显著的相关性(P<0.05),而这几个因素与体重的相关性不显著(P>0.05)。多因素非条件Logistic分析后发现:AA基因型对死亡率具有显著的影响(P<0.05),是主要的危险因素,而AB基因型的作用不显著(P>0.05);头长是主要的保护因素(P<0.05),体重对死亡率的影响很小。χ2检验证明,等位基因A是对死亡的主要危险等位基因,B是对存活有利的主要等位基因。推测该位点可以作为牙鲆抗迟缓爱德华氏菌的潜在标记。