用广角x光衍射测定不同晶型间规聚苯乙烯结晶度

根据广角 X光衍射 (WAXD)理论 ,对不同晶型间规聚苯乙烯 (α 、α"和 β )的 WAXD图进行计算机拟合多峰分解 ,计算出各晶型相应结晶衍射峰和无定形峰的校正系数 ,导出 α 、α"和 β 晶型的结晶度计算公式。并用示差扫描量热法 (DSC)对不同温度下充分结晶样品的结晶度加以求算和比较。结果表明 ,二者所得的结果相一致

Single-crystal X-ray structure and properties of K-10[Ni-4(H2O)(2)(AsW9O34)(2)]center dot 4H(2)O

The rational synthesis and the structural and magnetic characterization of a nickel cluster are presented. The compound comprises a rhomblike Ni4O16 group encapsulated between two-heptadentate tungstoarsenate ligands [AsW9O34](9-). The crystal structure of K-10[Ni-4(H2O)(2)(AsW9O34)(2)](.)4H(2)O was solved in monoclinic, P2(1)/n symmetry, with a = 12.258(3) Angstrom, b = 21.232(4) Angstrom, c = 15.837(3) Angstrom, beta = 92.05(3)degrees, V = 4119.1(14) Angstrom(3), Z = 2, and R = 0.0862. The crystal structure of the Ni(II) derivative was compared with that of the Cu(II), Zn(II), Co(II) and Mn(II) derivatives. The Ni4O14(H2O)(2) unit in the compound shows no Jahn-Teller distortion. On the other hand, the Ni(II) derivative shows ferromagnetic exchange interactions within the Ni4O16 group (J = 7.8 cm(-1), J' = 13.7 cm(-1)) and an S = 4 ground state, the highest spin state reported in a heteropoly complex. Its redox electrochemistry has been studied in acid buffer solutions using cyclic voltammetry. It exhibited two steps of one-electron redox waves attributed to redox processes of the tungsten-oxo framework. The new catalyst showed an electrocatalytic effect on the reduction of NO2-.

Chemical bond properties of rare earth ions in crystals

By using the dielectric description theory of ionicity of solids, chemical bond properties of rare earth ions with various ligands are studied. Calculated results show that chemical bond properties of the same rare earth ion and the same ligand in different crystals depend on the crystal structures. In a series of compounds, chemical bond properties of crystals containing different rare earth ions are similar. The magnitude of covalency of chemical bonds of trivalent rare earth ions and various ligands has an order like F

Electrochemical study of interactions between DNA and viologen-thiol self-assembled monolayers

We investigated the binding characteristics of double-stranded DNA to self-assembled monolayers (SAMs) containing viologen groups formed on the surface of gold electrodes via Au-S bonds. The positive charged and hydrophobic surfaces of the viologen SAMs modified gold electrodes are suitable to bind strongly dth DNA, whose interactions to solution DNA and adsorbed DNA both lead to positive shifts (22.5 mV and 65 mV, respectively) in the first redox potential ci viologen centers, indicating that the main interaction is from a hydrophobic interaction. Meanwhile, the binding of DNA strongly affects the kinetics of electron transfer of the viologen group so that the separation of anodic and cathodic peak potentials becomes larger and the heterogeneous electron transfer constant becomes smaller.

AiC1qDC-1, a novel gC1q-domain-containing protein from bay scallop Argopecten irradians with fungi agglutinating activity

The globular C1q-domain-containing (C1qDC) proteins are a family of versatile pattern recognition receptors via their globular C1q (gC1q) domain to bind various ligands including several PAMPs on pathogens. In this study, a new gC1q-domain-containing protein (AiC1qDC-1) gene was cloned from Argopecten irradians by rapid amplification of cDNA ends (RACE) approaches and expressed sequence tag (EST) analysis. The full-length cDNA of AiC1qDC-1 was composed of 733 bp, encoding a signal peptide of 19 residues and a typical gC1q domain of 137 residues containing all eight invariant amino acids in human C1qDC proteins and seven aromatic residues essential for effective packing of the hydrophobic core of AiC1qDC-1. The gC1q domain of AiC1qDC-1, which possessed the typical 10-stranded beta-sandwich fold with a jelly-roll topology common to all C1q family members, showed high homology not only to those of Cl qDC proteins in mollusk but also to those of C1qDC proteins in human. The AiC1qDC-1 transcripts were mainly detected in the tissue of hepatopancreas and also marginally detectable in adductor, heart, mantle, gill and hemocytes by fluorescent quantitative real-time PCR. In the microbial challenge experiment, there was a significant up-regulation in the relative expression level of AiC1qDC-1 in hepatopancreas and hemocytes of the scallops challenged by fungi Pichia pastoris GS115, Gram-positive bacteria Micrococcus luteus and Gram-negative bacteria Listonella anguillarum. The recombinant AiC1qDC-1 (rAiC1qDC-1) protein displayed no obvious agglutination against M. luteus and L. anguillarum, but it aggregated P. pastoris remarkably. This agglutination could be inhibited by D-mannose and PGN but not by LPS, glucan or D-galactose. These results indicated that AiC1qDC-1 functioned as a pattern recognition receptor in the immune defense of scallops against pathogens and provided clues for illuminating the evolution of the complement classical pathway. (C) 2010 Elsevier Ltd. All rights reserved.

Toxicity of lead, cadmium and mercury on embryogenesis, survival, growth and metamorphosis of Meretrix meretrix larvae

In order to assess the toxicity of heavy metals on the early development of Meretrix meretrix, the effects of mercury (Hg), cadmium (Cd) and lead (Pb) on embryogenesis, survival, growth and metamorphosis of larvae were investigated. The EC50 for embryogenesis was 5.4 mu g l(-1) for Hg, 1014 mu g l(-1) for Cd and 297 mu g l(-1) for Pb, respectively. The 96 h LC50 for D-shaped larvae was 14.0 mu g l(-1) for Hg, 68 mu g l(-1) for Cd and 353 mu g l(-1) for Pb, respectively. Growth was significantly retarded at 18.5 mu g l(-1) (0.1 mu M) for Hg, 104 mu g l(-1) (1 mu M) for Cd and 197 mu g l(-1) (1 mu M) for Pb, respectively. The EC50 for metamorphosis, similar to 48 h LC50, was higher than 96 h LC50. Our results indicate that the early development of M. meretrix is highly sensitive to heavy metals and can be used as a test organism for ecotoxicology bioassays in temperate and subtropical regions.

两种雀形目鸟类孵化行为对子代质量的影响

对高寒草甸地面营巢的小云雀（Alauda gulgula）和灌丛筑巢的黄嘴朱顶雀（Acanthis flavirostris）繁殖方式的研究表明：①小云雀孵化异步性较弱（1 d）；平均卵重与产卵顺序不显著相关，但最后1枚卵最重；出壳顺序与雏鸟生长率极显著正相关（P < 0.05）；出壳顺序对幼鸟的雏期和离巢体重无显著影响（P > 0.05）。②黄嘴朱顶雀孵化异步性较强（2～3）；平均卵重与产卵顺序显著正相关（P < 0.05），最后1枚卵最重，第1枚次之；出守则顺序对雏鸟生长率、雏期和离巢体重均无显著影响（P > 0.05）。结果分析表明，2种雀形目鸟类都选择了异步孵化和加强窜雏数对策的繁殖模式。

机械行业CIMS(计算机集成制造系统)体系结构

本文阐述了机械行业的CIMS体系结构,从计算机系统的层次和计算机支持系统的层次说明体系结构的二维层次关系。并以沈阳第一机械厂CIMS结构实例给予进一步说明。

贵州省务川汞矿区土法炼汞过程中汞释放量的估算

通过对贵州省务川汞矿区土法炼汞的矿石、冶炼矿渣中汞含量的测定,运用质量平衡原理,计算土法炼汞过程中汞释放因子,估算土法炼汞过程中汞的年释放通量. 贵州务川汞矿区土法炼汞的回收率为7814 %～9316 % ,释汞因子为619 %～3211 % ,土法炼汞的年释汞量为317～916t . 结果表明,务川汞矿区土法炼汞是该地区大气的最主要人为释汞源.

滇西金满铜矿床中木质结构及其成因意义

滇西金满脉状铜矿床,产于由砂岩、粉砂岩和页岩组成的含盐红色碎屑岩建造中.矿石中木质结构相当发育.组成木质结构的金属矿物主要是黄铁矿、黄铜矿和斑铜矿.通过对样品、显微照片和电子显微镜照片研究后,确定其为异木属,反映含矿岩系当为陆相环境的产物.有机地球化学和硫、碳同位素组成表明,矿床的形成实与地下热卤水和生物作用有关.

Active paraplegics are protected against exercise-induced oxidative damage through the induction of antioxidant enzymes

Exercise improves functional capacity in spinal cord injury (SCI). However, exhaustive exercise, especially when sporadic, is linked to the production of reactive oxygen species that may have a detrimental effect on SCI. We aimed to study the effect of a single bout of exhaustive exercise on systemic oxidative stress parameters and on the expression of antioxidant enzymes in individuals with paraplegia. The study was conducted in the Physical Therapy department and the Physical Education and Sports department of the University of Valencia. Sixteen paraplegic subjects were submitted to a graded exercise test (GET) until volitional exhaustion. They were divided into active or non-active groups. Blood samples were drawn immediately, 1 and 2 h after the GET. We determined plasma malondialdehyde (MDA) and protein carbonylation as markers of oxidative damage. Antioxidant gene expression (catalase and glutathione peroxidase-GPx) was determined in peripheral blood mononuclear cells. We found a significant increase in plasma MDA and protein carbonyls immediately after the GET (P<0.05). This increment correlated significantly with the lactate levels. Active paraplegics showed lower levels of exercise-induced oxidative damage (P<0.05) and higher exercise-induced catalase (P<0.01) and GPx (P<0.05) gene expression after the GET. These results suggest that exercise training may be useful in SCI patients to develop systemic antioxidant defenses that may protect them against exercise-induced oxidative damage.

Bitácora de bocetos : taller Ligia de Wiesner Manizales - Caldas.

19 hojas : ilustraciones, dibujos.