全球经济萧条与生产据点向中国的转移--21世纪亚洲工业化的新阶段

20世纪后期是亚洲工业化第一阶段,中国经济迅速发展,成为世界经济增长中心.外国资本纷纷投入中国市场,中国国内改革进入新的阶段.这对形成中国在内的亚洲经济圈,进入亚洲工业化第二阶段是至关重要的.     

皮秒Nd:YAG激光对生物金属纯Ti和Ti–13Nb–13Zr合金的表面改性

The effects of picosecond Nd:YAG laser irradiation on chemical and morphological surface characteristics of the commercially pure titanium and Ti–13Nb–13Zr alloy in air and argon atmospheres were studied under different laser output energy values. During the interaction of laser irradiation with the investigated materials, a part of the energy was absorbed on the target surface, influencing surface modifications. Laser beam interaction with the target surface resulted in various morphological alterations, resulting in crater formation and the presence of microcracks and hydrodynamic structures. Moreover, different chemical changes were induced on the target materials’ surfaces, resulting in the titanium oxide formation in the irradiation-affected area and consequently increasing the irradiation energy absorption. Given the high energy absorption at the site of interaction, the dimensions of the surface damaged area increased. Consequently, surface roughness increased. The appearance of surface oxides also led to the increased material hardness in the surface-modified area. Observed chemical and morphological changes were pronounced after laser irradiation of the Ti–13Nb–13Zr alloy surface.     

Arithmetization and Rigor as Beliefs in the Development of Mathematics

With the arrival of the nineteenth century, a process of change guided the treatment of three basic elements in the development of mathematics: rigour, the arithmetization and the clarification of the concept of function, categorised as the most important tool in the development of the mathematical analysis. In this paper we will show how several prominent mathematicians contributed greatly to the development of these basic elements that allowed the solid underpinning of mathematics and the consideration of mathematics as an axiomatic way of thinking in which anyone can deduce valid conclusions from certain types of premises. This nineteenth century stage shares, possibly with the Heroic Age of Ancient Greece, the most revolutionary period in all history of mathematics.     

High-throughput synthesis and catalytic properties of a molecular sieve with 18- and 10-member rings

Crystalline molecular sieves with large pores and high adsorption capacities have many potential applications. Of these materials, zeolites are of particular interest owing to their stability in a wide range of experimental conditions. An aluminophosphate with very large circular channels(5) containing 18 oxygen atoms (18-ring channels) has been synthesized, but in the search for large-pore zeolites, most of the materials which have been synthesized up to now contain only 14-ring channels; the synthesis of zeolites with larger ring structures has been believed to be hindered by the low Si-O-Si bond angles available. A silicogaloaluminate (ECR-34) with unidirectional 18-ring channels was recently reported, but exhibited low micropore volume, thus rendering the material less attractive for catalytic applications. Here we report the structure and catalytic activity of the silicogermanate zeolite ITQ-33; this material exhibits straight large pore channels with circular openings of 18-rings along the c axis interconnected by a bidirectional system of 10-ring channels, yielding a structure with very large micropore volume. The conditions for synthesis are easily accessible, but are not typical, and were identified using high-throughput techniques.     

Cluster Differences Unfolding for Two-Way Two-Mode Preference Rating Data

Classification and spatial methods can be used in conjunction to represent the individual information of similar preferences by means of groups. In the context of latent class models and using Simulated Annealing, the cluster-unfolding model for two-way two-mode preference rating data has been shown to be superior to a two-step approach of first deriving the clusters and then unfolding the classes. However, the high computational cost makes the procedure only suitable for small or medium-sized data sets, and the hypothesis of independent and normally distributed preference data may also be too restrictive in many practical situations. Therefore, an alternating least squares procedure is proposed, in which the individuals and the objects are partitioned into clusters, while at the same time the cluster centers are represented by unfolding. An enhanced Simulated Annealing algorithm in the least squares framework is also proposed in order to address the local optimum problem. Real and artificial data sets are analyzed to illustrate the performance of the model.     

信息量的度量及应用

将信息量数量化,借助数学工具——熵来度量信息总量的多寡,利用所得结论从理论上全面解决了古典利用天平寻找“坏球”问题.     

Pharmacologically active spider peptide toxins

Advances in mass spectrometry and peptide biochemistry coupled to modern methods in electrophysiology have permitted the isolation and identification of numerous novel peptide toxins from animal venoms in recent years. These advances have also opened up the field of spider venom research, previously unexplored due to methodological limitations. Many peptide toxins from spider venoms share structural features, amino acid composition and consensus sequences that allow them to interact with related classes of cellular receptors. They have become increasingly useful agents for the study of voltage-sensitive and ligand-gated ion channels and the discrimination of their cellular subtypes. Spider peptide toxins have also been recognized as useful agents for their antimicrobial properties and the study of pore formation in cell membranes. Spider peptide toxins with nanomolar affinities for their receptors are thus promising pharmacological tools for understanding the physiological role of ion channels and as leads for the development of novel therapeutic agents and strategies for ion channel-related diseases. Their high insecticidal potency can also make them useful probes for the discovery of novel insecticide targets in the insect nervous system or for the development of genetically engineered microbial pesticides.Received 19 March 2003; received after revision 9 May 2003; accepted 16 May 2003     

19世纪英、德两国教育中的民族性之比较

英国曾是世界上最强大的经济实体,自命日不落帝国.但进入20世纪后,英国却不可挽回地迅速衰退了.与此同时,德国在1871年统一之前还是长期陷于四分五裂和处于封建割据的国家,却在20世纪初成为一个后起的资本主义国家,经济实力超过英国,仅次于美国跃居世界第二位.本文就英国的衰落和德国的崛起,从其在文化教育中所体现出的民族特性进行浅析,并藉此对中国当前的教育改革和发展作点探索和思考.     

TGFβ-induced protein mediates lymphatic endothelial cell adhesion to the extracellular matrix under low oxygen conditions

TGFbeta-induced protein (TGFBI) is an extracellular protein that mediates cell adhesion to collagen, laminin and fibronectin through its interaction with different beta integrins. We had previously reported that hypoxia-induced TGFBI mRNA expression in lymphatic endothelial cells (LEC). Here, we demonstrate that TGFBI can contribute to hypoxia-induced increases in LEC adhesion to the ECM. We show that while there are no changes in alpha1, alpha4, alphav, beta1, beta2, beta3, alpha5beta1, alphavbeta3, alphavbeta5 integrin expression on the LEC surface after hypoxia exposure, there exists an accumulation of TGFBI adaptor protein in LEC supernatants. We also demonstrate that hypoxia driven TGBFI expression is dependent on TGFbeta production by LEC. Furthermore, we show that TGFBI mediated LEC adhesion and migration through the ECM by its binding to the beta3 integrin. The identification of the specific mechanisms regulating LEC-ECM interactions may help us design new therapeutic applications for diseases in which lymphatic vessel function is compromised.