近丘间低地沙障促进沙丘植被恢复的效应

流动沙丘区的丘间低地的土壤种子库大,种类丰富,但其对流动沙丘植被恢复的作用尚不清楚。以科尔沁沙地为研究对象,在靠近丘间低地的下风向裸沙段设置沙障,研究了其对土壤种子库、幼苗出土与植物定居的效应。结果表明:沙障处土壤种子库物种数和密度都显著大于对照处(P<0.05),5～10cm深度种子密度达到土壤种子库密度的60%,而对照处低于50%;沙障内的沙生植物出土和定居幼苗密度都显著大于对照处(P<0.001),沙障处与对照处的非沙生植物出土幼苗密度低于1株.m-2,建植幼苗密度低至0.1株.m-2;对照处种子数与幼苗出土和定居的相关性相对于沙障处的更强,沙生植物种子数与幼苗出土和定居的相关性相对于非沙生植物的更强;对照处种子库与幼苗出土和定居的物种组成相似性较沙障处大,沙生植物种子库与幼苗出土和定居的相似性较非沙生植物大。可见,沙障截留来自丘间低地的种子增加了流动沙丘的土壤种子库种类和密度,改变了土壤种子库的空间格局;沙障的设立提高了沙生植物幼苗的出土和物种定居的水平,但没有显著提高非沙生植物幼苗的萌发和建植。

土壤侵蚀退化研究进展

从土壤物理退化、化学退化和生物学退化等3个方面回顾了国内外的土壤退化过程研究的历史与现状，全面总结了国内外在土壤侵蚀退化形成的过程、机理、影响因素以及评价土壤退化的指标方法等方面的最新研究进展，最后提出了土壤退化过程和防治方法研究中存在的主要问题，并从多学科交叉的角度和土壤侵蚀退化机理研究及定量动态监测角度来展望土壤侵蚀退化研究的进一步发展方向。

Lung alveolar proteomics of bronchoalveolar lavage from a pulmonary alveolar proteinosis patient using high-resolution FTICR mass spectrometry

High-resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometry was developed and applied to the proteome analysis of bronchoalveolar lavage fluid (BALF) from a patient with pulmonary alveolar proteinosis. With use of 1-D and 2-D gel electrophoresis, surfactant protein A (SP-A) and other surfactant-related lung alveolar proteins were efficiently separated and identified by matrix-assisted laser desorption/ionization FTICR mass spectrometry . Low molecular mass BALF proteins were separated using a gradient 2-D gel. An efficient extraction/precipitation system was developed and used for the enrichment of surfactant proteins. The result of the BALF proteome analysis show the presence of several isoforms of SP-A, in which an N-non-glycosylierte form and several proline hydroxylations were identified. Furthermore, a number of protein spots were found to contain a mixture of proteins unresolved by 2-D gel electrophoresis, illustrating the feasibility of high-resolution mass spectrometry to provide identifications of proteins that remain unseparated in 2-D gels even upon extended pH gradients.

Syntheses and crystal structures of bis(tetrahydrofurfurylindenyl) lanthanocene chlorides (C4H7OCH2C9H6)(2)LnCl (Ln = La, Lu)

Reaction of two equivalents of tetrahydrofurfuryl indenyl lithium with anhydrous lanthanide trichlorides in THF afforded bis(tetrahydrofurfurylindenyl) lanthanide chlorides (C4H7OCH2C9H6)(2)LnCl, Ln=La(l), Pr(2), Lu(3). Complexes I and 3 are characterized by single-crystal analysis. The results of crystal structural determination reveal that they are 9-coordinate monomeric intramolecular complexes with a trans arrangement of both the sidearms and indenyl rings in the solid state. The effects of rare earth ionic radii on the structures Of (C4H7OCH2C9H6)(2)LnCl are discussed.

Circular dichroism spectro electrochemical and voltammetric studies of vitamin B-2

Electroreduction of vitamin B-2 (VB2) was studied by in situ circular dichroism (CD) spectroelectrochemistry (SEC) with a long optical path length thin layer cell (LOPLTLC). The results showed that the electroreduction of VB2 in phosphate buffer solution (PBS) (PH 6.8) was a two-electron electrochemical process with weak adsorption of the reactant at the glassy carbon (GC) electrode surface. The CD spectra change of VB2 in the reduction process was explained with the theory of electronic states. We also treated the CD spectra with a singular value decomposition least square (SVDLS) method, and have found not only the number of components and their spectra, but also the fraction distribution of each component in the electroreduction process of VB2.

Local similarity in organic crystals and the non-uniqueness of X-ray powder patterns

Two new concepts for molecular solids, 'local similarity' and 'boundary-preserving isometry', are defined mathematically and a theorem which relates these concepts is formulated. 'Locally similar' solids possess an identical short-range structure and a 'boundary-preserving isometry' is a new mathematical operation on a finite region of a solid that transforms mathematically a given solid to a locally similar one. It is shown further that the existence of such a 'boundary-preserving isometry' in a given solid has infinitely many 'locally similar' solids as a consequence. Chemical implications, referring to the similarity of X-ray powder patterns and patent registration, are discussed as well. These theoretical concepts, which are first introduced in a schematic manner, are proved to exist in nature by the elucidation of the crystal structure of some diketopyrrolopyrrole (DPP) derivatives with surprisingly similar powder patterns. Although the available powder patterns were not indexable, the underlying crystals could be elucidated by using the new technique of ab initio prediction of possible polymorphs and a subsequent Rietveld refinement. Further ab initio packing calculations on other molecules reveal that 'local crystal similarity' is not restricted to DPP derivatives and should also be exhibited by other molecules such as quinacridones. The 'boundary-preserving isometry' is presented as a predictive tool for crystal engineering purposes and attempts to detect it in crystals of the Cambridge Structural Database (CSD) are reported.

低氧对CRF、AVP和NE刺激体外培养腺垂体细胞生成cAMP的影响

本文探讨了CRF,AV P 及N E 对体外培养大鼠腺垂体细胞生成cAM P的作用。CRF 刺激体外培养大鼠腺垂体细胞内cAM P 的生成, 且浓度与效应正相关。AV P 未引起细胞内cAM P 差异性变化(P > 0.5)。N E 使培养腺垂体细胞内cAM P 水平降低。低氧使CRF 刺激cAM P 生成的作用降低。而AV P 及N E 可能是通过其它胞内信息通路。

集成化企业建模方法与工具系统研究

研究了企业建模方法的发展趋势 ,提出了一个集成化的企业建模方法 ,给出了建模框架体系和建模方法 ,并设计了一个基于CORBA软件总线的集成化企业建模与仿真优化系统。所提出的建模方法与设计的软件工具 ,对于促进集成化企业建模方法学的研究 ,开发具有我国自主版权的建模与优化工具系统 ,具有实际应用价值。