沈阳市郊秋菜田的景观生态研究Ⅰ.秋菜田斑块特征

对沈阳市郊区农业景观中的秋菜田斑块的大小、形状及与其它斑块或廊道的邻接情况等基本特征进行了典型调查 ,分析和讨论了菜田斑块在该景观中的镶嵌特征 .在距城区约 5km以内的近郊区 ,许多秋菜田斑块相互邻接 ,并与各类公路相邻接 ;距城区 5～ 10km的中郊区 ,许多秋菜田斑块与玉米田斑块相邻接 ,并与乡村道路相邻接 ;在距城区 10km以上的远郊区 ,多数秋菜田斑块被玉米田斑块所包围 ,并与乡村道路相邻接 .

环境地理与人类健康研究成果与展望

中国科学院地理科学与资源研究所倡导和建立了化学地理研究机构,是我国最早从事环境科学研究的单位之一,推动了环境质量调查、环境质量评价、环境背景、环境容量和环境治理等理论和技术的建立和发展;长期进行克山病、大骨节病等地方病的调查及其环境病因与防治的研究,为上述疾病的控制做出了重大贡献;创立和发展了中国的医学地理学研究体系。2000年以后,在持续开展西部地方病地理流行规律和稀土元素生物地球化学循环研究基础上,重点开展了重金属等污染物及全球环境变化的健康风险评价研究,拓展了区域碳、氮、磷等生命元素的生物地球化学循环与温室气体排放的关系研究,强化了环境污染治理和健康保护的技术研究。实现了从化学地理到环境地理、从医学地理到健康地理的转变。未来的环境地理与人类健康研究将以地理环境的化学属性为重点,以人口健康保护为核心,探讨环境保护、社会经济发展和人类健康安全在整体上协调的机制与途径。

中药羚羊角及其类似品中水溶性蛋白的检测

目的:研究中药羚羊角及其类似品中水溶性蛋白组分差异及鉴定方法,为其药效组分质量评价体系的建立提供科学数据。方法:采用紫外分光光度法(UV)和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)技术,对羚羊角及其类似品山羊角和黄羊角进行水溶性蛋白质含量和组分对比分析。结果:羚羊角中水溶性蛋白的含量高于黄羊角和山羊角,且3种角类中药蛋白组分的组成差异显著。结论:蛋白组分可用于羚羊角的鉴定,采用药效蛋白组分评价角类中药质量具有明显的科学性和实用性。

一种新型直接甲醇燃料电池阳极添加剂的电化学研究

将磷钼酸 (H4PMo12 O40 ·xH2 O ,PMo12 )作为一种添加剂 ,制备了直接甲醇燃料电池阳极Pt Ru/C PMo12 复合催化剂 ,并对甲醇在含有此复合催化剂的阳极上的氧化进行了电化学研究 .测试表明该添加剂降低了甲醇及其电氧化中间产物转化的活化能 ,改善了电极内部的质子传输状况 ,对甲醇的电化学氧化过程具有明显的促进作用 ,该复合催化剂与常规的Pt Ru/C催化剂相比 ,甲醇的阳极氧化电流提高了 46% .添加剂的这一效应可能与磷钼酸的Keggin结构有关

Simultaneous determination of tramadol and lidocaine in urine by end-column capillary electrophoresis with electrochemiluminescence detection

Tramadol and lidocaine, used as analgesic and local anesthetic in surgery, are partly excreted by kidney. For the first time, we developed a simple and sensitive method, based on capillary electrophoresis with electrochemiluminescence (ECL) detection by end column mode without joint to monitor tramadol and lidocaine in urine. To eliminate the influence of ionic strength of urine sample, analytes were extracted by ether. Tripropylamine (TPA) was used as internal standard. ne recoveries of tramadol and lidocaine were between 94% and 97% at different levels. The method exhibited the linear range for the tramadol and lidocaine from 1.0 X 10(-7) to 1.0 X 10(-4) mol/L with correlation efficient of 0.998. The relative standard deviation (RSD) was 2.9% and 2.7% (n = 8) for tramadol and lidocaine, respectively. The limit of detection (LOD) was 6.0 x 10(-8) mol/L and 4.5 x 10(-8), mol/L (S/N = 3) for tramadol and lidocaine, respectively. The application for detecting tramadol and lidocaine in urine of patients showed that the method was valuable in clinical and biochemical laboratories for detecting tramadol, lidocaine and other tertiary amine pharmaceuticals for various purpose, such as metabolism investigation.

Cardo polyarylethersulfones and polyaryletherketones bearing alkyl substituents on the phenylene unit

A series of cardo polyaryletherketones and polyaryletersulfones containing alkyl substituents of a different kind, number and volume were synthesized from bis(4-nitrophenyl)ketone or bis(4-fluorophenyl)sulfone with various alkyl substituted phenolphthaleins by polycondensation using K2CO3 as catalyst. Their chemical and aggregation structures were confirmed by FT-IR, H-1-NMR and WAXD. The resulting polymers were soluble in a variety of common polar solvents and, transparent, colorless, and tough films could be easily cast from 1,1,2-trichluoroethane solution. Their tensile strength, elongation at break and tensile modulis were in the range of 70.5 similar to 97.1MPa, 4.49%similar to7.81%, and 1.69 similar to2.27GPa, respectively. The prepared polymers had reasonably high glass transition temperatures at 207 to 269 degreesC, and showed fairly good thermal stability with 5% thermal decomposition loss above 410 degreesC.

Characterization of the structural and functional changes of hemoglobin in dimethyl sulfoxide by spectroscopic techniques

Circular dichroism (CD), fourier transform infrared (FTIR), and fluorescence spectroscopy were used to explore the effect of dimethyl sulfoxide (DMSO) on the structure and function of hemoglobin (Hb). The native tertiary structure was disrupted completely when the concentration of DMSO reached 50% (v/v), which was determined by loss of the characteristic Soret CD spectrum. Loss of the native tertiary structure could be mainly caused by breaking the hydrogen bonds, between the heme propionate groups and nearby surface amino acid residues, and by disorganizing the hydrophobic interior of this protein. Upon exposure of Hb to 52% DMSO for ca. 12 h in a D2O medium no significant change in 1652 cm(-1) band of the FTIR spectrum was produced, which demonstrated that alpha-helical structure predominated. When the concentration of DMSO increased to 57%: (1) the band at 1652 cm(-1) disappeared with the appearance of two new bands located at 1661 and 1648 cm(-1); (2) another new band at 1623 cm(-1) was attributed to the formation of intermolecular beta-sheet or aggregation, which was the direct consequence of breaking of the polypeptide chain by the competition of S=O groups in DMSO with C=O groups in amide bonds. Further increasing the DMSO concentration to 80%, the intensity at 1623 cm(-1) increased, and the bands at 1684, 1661 and 1648 cm(-1) shifted to 1688, 1664 and 1644 cm(-1), respectively. These changes showed that the native secondary structure of Hb was last and led to further aggregation and increase of the content of 'free' amide C=O groups. In pure DMSO solvent, the major band at 1664 cm(-1) indicated that almost all of both the intermolecular beta-sheet and any residual secondary structure were completely disrupted. The red shift of the fluorescence emission maxima showed that the tryptophan residues were exposed to a greater hydrophilic environment as the DMSO content increased. GO-binding experiment suggested that the biological function of Hb was disrupted seriously even if the content of DMSO was 20%. (C) 1998 Elsevier Science B.V. All rights reserved.

Studies on the two class glass transition and the typical VTF behaviour of an amorphous comb polymer electrolyte

A comb polymer (CP350) with oligo-oxyethylene side chains of the type -(CH2CH2O)(7)CH3 was prepared from methyl vinyl ether/maleic anhydride copolymer and poly(ethylene glycol) methyl ether. The polymer can dissolve LiNO3 salt to form homogeneous amorphous polymer electrolyte. This electrolyte system was first found to have two class glass transitions, and the two T(g)s were observed to increase with increasing salt content. The ionic conduction was measured by using the complex impedance method, and conductivities were investigated as functions of temperature and salt concentration. At 25 degrees C, the ionic conductivity maximum of this system can get to 3.72 X 10(-5) S/cm at the [Li]/ [EO] ratio of 0.057. The appearance of the conductivity maximum has been interpreted as being due to the effect of T-g and the so called physical crosslinks. The temperature dependence of the ionic conductivity displaying non-Arrhenius behaviour can be analyzed using the Vogel-Tammann-Fulcher equation and interpreted on the basis of the configurational entropy model.

无定形梳状高分子固体电解质的二重玻璃化转变及典型VTF特征

研究了交替马来酸酐共聚物多缩乙二醇酯（ＣＰ３５０）－ＬｉＮＯ３络合物的热行为及离子导电性。实验表明：ＣＰ３５０／ＬｉＮＯ３络合物在所研究的［Ｌｉ］／［ＥＯ］配比范围呈均相无定形并具有二重玻璃化转变。２个玻璃化转变温度均随盐含量的增加而上升。离子电导率随盐浓度的变化出现１个极大值，室温电导率最大可达３．７２×１０－５Ｓ／ｃｍ。导电行为呈典型ＶＴＦ特征。

Effect of storage time and cryoprotectant concentrations on the fertilization rate and hatching rate of cryopreserved sperm in red seabream (Pagrus major Temminck & Schlegel, 1843)

This study examined the effects of storage time and cryoprotectant concentrations on the post-thaw sperm of red seabream, Pagrus major. Sperm treated with 12%, 15%, 18% and 21% DMSO were cryopreserved for 10, 30, 60 and 360 days, and fertilization and hatching rates were analysed. For all groups, there were no differences in the fertilization rates and hatching rates between sperm cryopreserved for < 60 days and fresh sperm (98.8 +/- 0.8%, 96.4 +/- 1.3%). However, for sperm cryopreserved for 360 days, both fertilization rates (88.6 +/- 3.0% to 7.0 +/- 1.9%) and hatching rates (79.4 +/- 7.2% to 3.3 +/- 0.8%) decreased drastically. Furthermore, the cryoprotectant concentrations affected sperm quality significantly (P < 0.05). When cryopreserved for 360 days, sperm treated with 15% DMSO obtained the best results compared with other concentrations. We suggest that 15% DMSO may be an effective cryoprotectant for long-term sperm cryopreservation of red seabream.

Roles of microRNA in plant defense and virus offense interaction

MicroRNAs (miRNA) that are around 22 nucleotides long non-protein-coding RNAs, play key regulatory roles in plants. Recent research findings show that miRNAs are involved in plant defense and viral offense systems. Advances in understanding the mechanism of miRNA biogenesis and evolution are useful for elucidating the complicated roles they play in viral infection networks. In this paper a brief summary of evolution of plant anti-virus defense is given and the function of miRNAs involved in plant-virus competition is highlighted. It is believed that miRNAs have several advantages over homology-dependent and siRNA-mediated gene silencing when they are applied biotechnologically to promote plant anti-virus defense. miRNA-mediated anti-virus pathway is an ancient mechanism with a promising future. However, using miRNAs as a powerful anti-virus tool will be better realized only if miRNA genomics and functions in plant viral infection are fully understood.

人工栽培抱茎獐牙菜矿物质元素含量的研究

采集种子采收前和采收后的抱茎獐牙莱全植株，分别分析测试其钾、钠、钙、镁等矿物质元素的含量。结果表明：青海西宁廿里铺种植抱茎獐牙菜矿物质元素主要分布于植株的茎杆部位，矿物质元素含量在成熟种子采收前后具有动态性变化的特征。

开展高技术情报跟踪与服务的几点做法

开展高技术情报跟踪与服务是科技情报工作的重要任务之一,结合完成国家科委、科学院和国家863等高技术情报研究项目的多年实践,叙述了为我国高技术研究创造良好的文献情报支撑环境,主动为高技术研究服务的几点做法。