沿海防护林体系生态环境效益及评价技术

本文是“八五”国家科技攻关专题“沿海防护林体系生态经济效益及其评价技术”的阶段性研究成果，在国内首次系统地阐明了沿海防护林体系的中尺度气象效应、区域性气候效应、降盐改土效应、海堤林带的固土护堤效应和沿海农田林网的抗灾保产效应。

远紫外辐射对紫杉幼苗针叶膜脂过氧化及内源保护系统的影响

实验室条件下用远紫外线 (UV BC)光源照射紫杉幼苗 ,随照射时间延长 ,针叶的离子渗出率、膜脂过氧化水平、组织自动氧化速率及H2 O2 含量显著增加 ,可溶性蛋白、抗坏血酸、类胡萝卜素和叶绿素含量下降 ,叶绿体光系统II电子传递活性显著下降 ,外源活性氧清除剂苯甲酸钠和抗坏血酸对针叶膜脂过氧化有抑制作用 ;甲基紫精和DDC对针叶膜脂过氧化有促进效果 ,远紫外线引起的紫杉伤害可能和针叶树的越冬光氧化伤害有类似之处 .紫杉苗对紫外辐射的抗性远高于一般农作物 .

中国东北西部地区沙质荒漠化过程与植被动态关系的生态学研究:植被的分类

根据东北沙质荒漠化地区呼伦贝尔沙地、科尔沁沙地的 72个沙地植物群落样地、2 76种植物的调查数据 ,进行双向指示种分析 (TWINSPAN) ,结合DCA排序得到符合客观实际的分类结果 ,初步建立了中国东北沙质荒漠化地区植被分类系统 ,6个植被型 ,11个植被亚型 ,40个群系 ,5 5个群丛

资源区域流动的驱动因子分析与流动潜力测度:以晋煤输出为例

论文采用国家铁路省际间煤炭资源的交流数据、动力煤价格数据,以全国最大的煤炭输出省--山西为例,运用回归分析等统计方法,分析了资源区域流动的驱动因子。基于场论,提出了测度资源区域流动潜力的方法。主要结论有:①资源区域流动的主要驱动因子有距离、价格差;②在显著性水平α=0.05下,区域煤炭价格差与晋煤净输流量呈正向变化,但线性无关,源汇间距离与晋煤净输流量呈线性负相关;③2005年晋煤净输流量与源汇间距离符合F=e9.091-0.003D的Growth回归模型;④资源势差涵盖了影响煤炭流动的流量和距离等2个主

内蒙古鄂温克族牧民砖茶型氟铝联合中毒调查

目的调查鄂温克族牧民砖茶型氟铝联合中毒病情。方法随机对鄂温克族16~55岁男女均衡62名牧民进行发、血清、尿氟铝水平及血清电解质、生物化学检查,同时检测饮水、牛奶、砖茶、奶茶等氟铝水平,并进行临床检诊和拍摄前臂、骨盆正位X线片,不饮用砖茶的16~55岁男女均衡41名居民为对照组。结果发、血清、尿铝水平牧民组分别为(24.60±9.82)mg/Kg、(0.78±0.25)、(2.84±0.65)mg/L,对照组分别为(12.50±4.55)mg/kg、(0.18±0.11)、(2.09±0.64)mg/L;发、血清、尿氟水平牧民组分别为(1.00±0.52)mg/kg、(0.10±0.10)、(2.74±1.42)mg/L,对照组分别为(1.39±1.34)mg/kg、(0.04±0.03)、(0.87±0.43)mg/L;牧民发、血、尿铝及血、尿氟显著高于对照组(P<0.01)。牧民组血清AST、LDH、HBDH、ALP显著高于对照组(P<0.01)。X线摄片牧民组氟骨症检出率50.00%,关节退行性变检出率61.29%,骨间膜骨化33.87%,疏松型改变检出率29.03%,硬化型改变检出率8.06%;对照组氟骨症检出率2.44%,退行性变检出率34.15%,疏松型改变检出率21.95%,骨间膜骨化检出率2.44%,硬化型改变2.44%,X线氟骨症、关节退行性变、骨间膜骨化牧民组均高于对照组(P<0.01)。结论内蒙古鄂温克族牧民饮茶型氟中毒病情较为严重,其发病机理较为复杂,并导致多组织、器官损伤,可能为砖茶型氟铝联合中毒。

Co-electrospun poly(lactide-co-glycolide), gelatin, and elastin blends for tissue engineering scaffolds

In this study, we describe composite scaffolds composed of synthetic and natural materials with physicochemical properties suitable for tissue engineering applications. Fibrous scaffolds were co-electrospun from a blend of a synthetic biodegradable polymer (poly(lactic-co-glycolic acid), PLGA, 10% solution) and two natural proteins, gelatin (denatured collagen, 8% solution) and (x-elastin (20% solution) at ratios of 3:1:2 and 2:2:2 (v/v/v). The resulting PLGA-gelatin-elastin (PGE) fibers were homogeneous in appearance with an average diameter of 380 80 mn, which was considerably smaller than fibers made under identical conditions from the starting materials (PLGA, 780 +/- 200 nm; gelatin, 447 +/- 1.23 nm; elastin, 1060 170 nm). Upon hydration, PGE fibers swelled to an average fiber diameter of 963 +/- 132 nm, but did not disintegrate. Importantly, PGE scaffolds were stable in an aqueous environment without crosslinking, and were more elastic than those made of pure elastin fibers. To investigate the cytocompatibility of PGE, we cultured H9c2 rat cardiac myoblasts and rat bone marrow stromal cells (BMSCs) on fibrous PGE scaffolds. We found that myoblasts grew equally as well or slightly better on the scaffolds than on tissue-culture plastic. Microscopic evaluation confirmed that myoblasts reached confluence on the scaffold surfaces while simultaneously growing into the scaffolds.

Controlling dispersed state and exfoliation process of clay in polymer matrix

In the present review, the authors do not try to provide a comprehensive review of researches on polymer/clay nanocomposites (PCNs), but some examples to demonstrate different exfoliation processes of the clay in various polymer matrixes and the dispersed state of clay. Interaction between polymers and layered silicates plays an important role in adjusting the exfoliation process of layered silicates and the microstructure of polymer nanocomposites. Properties of polymer/layered silicate nanocomposites mainly depend on the dispersed state of layered silicates. The authors will also address the outline of the present research in the direction of PCNs including the discussion of technical problems and their possible solutions.

STATISTICAL THERMODYNAMICS IN THE FRAMEWORK OF THE LATTICE FLUID MODEL .2. BINARY MIXTURE OF POLYDISPERSE POLYMERS OF SPECIAL DISTRIBUTION

In this paper, the Gibbs free energy, the equation of state and the chemical potentials of polydisperse multicomponent polymer mixtures are derived. For general binary mixtures of polydisperse polymers, we also give the Gibbs free energy, the equation of

有机化合物结构异构体的穷举生成——Ⅰ.从分子式穷举生成结构片断集

结构产生器是有机化合物结构自动解析专家系统的核心部分,它从分子式出发,穷举生成结构基元向量,结构片断向量,最后对接成整体结构。本文详细介绍了ESESOC-Ⅱ(Expert System for the Elucidation of the Structures of Organic Compounds)系统的结构基元和结构片断的定义,并阐述了如何利用组合数学原理从分子式出发穷举生成结构基元向量和结构片断向量及结构片断集的算法。

THE VALENCE CHANGE FROM RE3+ TO RE2+ (RE-EQUIVALENT-TO-EU, SM, YB) IN SRB4O7-RE PREPARED IN AIR AND THE SPECTRAL PROPERTIES OF RE2+

A valence change from RE3+ to RE2+ (RE=Eu, Sm, Yb) was observed in samples of SrB4O7: RE prepared by solid state reaction at high temperature in air. The phosphors SrB4O7: RE2+ show efficient luminescence at room temperature. The broad band d-f emissions of Eu2+ and Yb2+ are at 367 and 360 nm respectively. The sharp line f-f emissions of the Sm2+ ion (5D0-F-7(J)) are in the range 680-780 nm. The probable reasons for the valence change of Eu, Sm and Yb in this host are discussed.

Li-Ni-La-O系复合氧化物催化剂上甲烷氧化偶联的研究

考察了Li-Ni-La-O系催化剂的组成、结构及反应条件对甲烷氧化偶联反应活性的影响.在780℃、CH_4:O_2:N_2=2:1:7、空速15000h~(-1)时,C_2烃收率可达25.8％.XRD、IR、XPS及SEM等的结构分析表明,在LiLa_(1-x)Ni_xO_2催化剂中,当0.1≤x≤0.9时,该催化剂由LiNiO_2和LaNi_(1-y)Li_yO_(4-λ)两相组成,x<0.3时出现了LiLaO_2相,La_2Ni_(1-y)Li_yO_(4-λ)是甲烷氧化偶联的主要活性相,活性位Li~+-O~--Ni~(2+)数量的增加是活性提高的主要原因.LiNiO_2和LiLaO_2也有催化活性,它们与La_2Ni_(1-y)Li_yO_4间的协同作用也可能是催化活性增强的原因.

甲烷氧化偶联La-Mn-Li系复合氧化物催化剂的研究

用XRD、IR、XPS和SEM等方法研究了混合氧化物LiLa_(1-x)Mn_xO_2的结构和它们对甲烷氧化偶联的催化性能。结果表明,随着MnO_2的变化,可形成一系列复合氧化物,其中三元复合氧化物La_2Mn_(1-y)Li_yO_4是甲烷氧化偶联的活性相,由于Li~+部分取代Mn~(2+)形成Li~+-O~--Mn(2+)缺陷簇,增加了活性氧种的浓度和再生速度是这种氧化物具有较高甲烷偶联活性的主要原因。脉冲实验证明,CH_4脱氢生成CH_3·偶联生成C_2H_6,进一步氧化脱氢生成C_2H_4都可在催化剂表面完成,而CO和CO_2是在气相反应中生成的。在780℃C_2收率可达23.9%。

[Cp_2ErCl(THF)]_2的晶体结构

本文报导了(Cp_2ErCl(THF)]_2的晶体结构,晶体属单斜晶系,P2_1/c空间群。晶胞参数为a=8.141(2),b=21.218(6),c=8.597(2),β=107.77(2)°;V=1414.1(6) ~3;Z=2,D_c=1.90g/cm~3,F(000)=780,μ_c=66.3cm~(-1)(MoK_a)。最终的偏离因子R=0.047,R_(to)=0.048。结构分析表明,该配合物是以两个氯离子与金属离子桥联的二聚体形式存在。四氢呋喃中的氧原子同金属离子键合,Er—O键长为2.490(6),两个环戊二烯中的所有碳原子同金属离子间的平均键长为2.649,Er-Cl=2.666(3),Er—Cl-a=2.797(3),Er-Er_a=4.42,Cl-Er-Cl_a键角为72.2°。

Cflec-4, a multidomain C-type lectin involved in immune defense of Zhikong scallop Chlamys farreri

C-type lectins are a superfamily of carbohydrate-recognition proteins which play crucial roles in the innate immunity. In this study, a novel multidomain C-type lectin gene from scallop Chlamys farreri (designated as Cflec-4) was cloned by RACE approach based on EST analysis. The full-length cDNA of Cflec-4 was of 2086 bp. The open reading frame was of 1830 bp and encoded a polypeptide of 609 amino acids, including a signal sequence and four dissimilar carbohydrate-recognition domains (CRDs). The deduced amino acid sequence of CflecA shared high similarities to other C-type lectin family members. The phylogenetic analysis revealed the divergence between the three N-terminal CRDs and the C-terminal one, suggesting that the four CRDs in Cflec-4 originated by repeated duplication of different primordial CRD. The potential tertiary structure of each CRD in Cflec-4 was typical double-loop structure with Ca2+-binding site 2 in the long loop region and two conserved disulfide bridges at the bases of the loops. The tissue distribution of Cflec-4 mRNA was examined by fluorescent quantitative real-time PCR. In the healthy scallops, the Cflec-4 transcripts could be only detected in gonad and hepatopancreas, whereas in the Listonella anguillarum challenged scallops, it could be also detected in hemocytes. These results collectively suggested that CflecA was involved in the immune defense of scallop against pathogen infection and provided new insight into the evolution of C-type lectin superfamily. (C) 2009 Elsevier Ltd. All rights reserved.