The Recent Uses of Sol-Gel Doped Catalysts in Fine Chemistry

A variety of sol-gel entrapped catalysts is available on the chemical market due to the unique advantages offered by these highly porous oxides doped with transition metal catalyst, enzymes or even living cells. Catalytic sol-gel lipase immobilizates were rapidly commercialized by Fluka after their invention by Reetz and coworkers in 1995 and have now reached a 2^nd generation level of performance. Besides esterification reactions these materials are also excellent catalysts in the kinetic resolution of chiral alcohols and amines, and are recyclable without any substantial loss in enantioselectivity （residual activity of 70 % even after 20 reaction cycles）.     

Place Marketing and Management: A Complex Adaptive Systems View. The Strategic Planning of the City of Avellino,Italy

The objective of this work is to contribute to place management and marketing studies by looking at the territory, as a complex adaptive system aiming to reach a dynamic equilibrium—a steady state. According to this approach, the territorial system emerges as a result of its capacity, its social actors and governance, and the analysis, creation and maintenance of relationships—the dynamics—between the territory components, both tangible and intangible ones, and its many and varied stakeholders. These relational dynamics produce continuous and reciprocal adaptive behaviours among social actors who determine, influence, and adapt the vision of the territory. Through an interdisciplinary approach, we evaluate the recent literature on town planning and geography, aiming to bridge the gap in place management and marketing literature. We propose a framework based on systemic and complexity theory and propose a novel approach that supports decision makers in modelling the future scenario, taking choices regarding place management and place marketing.     

~(238)U束流发射度的测量

为实现236U的高灵敏测量,对意大利那不勒斯第二大学的同位素研究环境与文化遗产中心的加速器质谱装置进行了升级改造。采用单缝单丝法测量了238U的束流发射度,并与13C和H的束流发射度进行了比较。测量结果表明,238U在X方向和Y方向的边界发射度分别为(9.5±1.0)、(2.7±0.3)mm.m rad。根据测量的发射度数值,确定了拟安装的飞行时间探测器在束流线上的位置。     

Structure of eEF3 and the mechanism of transfer RNA release from the E-site

Elongation factor eEF3 is an ATPase that, in addition to the two canonical factors eEF1A and eEF2, serves an essential function in the translation cycle of fungi. eEF3 is required for the binding of the aminoacyl-tRNA-eEF1A-GTP ternary complex to the ribosomal A-site and has been suggested to facilitate the clearance of deacyl-tRNA from the E-site. Here we present the crystal structure of Saccharomyces cerevisiae eEF3, showing that it consists of an amino-terminal HEAT repeat domain, followed by a four-helix bundle and two ABC-type ATPase domains, with a chromodomain inserted in ABC2. Moreover, we present the cryo-electron microscopy structure of the ATP-bound form of eEF3 in complex with the post-translocational-state 80S ribosome from yeast. eEF3 uses an entirely new factor binding site near the ribosomal E-site, with the chromodomain likely to stabilize the ribosomal L1 stalk in an open conformation, thus allowing tRNA release.     

A single motif responsible for ubiquitin recognition and monoubiquitination in endocytic proteins

Ubiquitination is a post-translation modification in which ubiquitin chains or single ubiquitin molecules are appended to target proteins, giving rise to poly- or monoubiquitination, respectively. Polyubiquitination targets proteins for destruction by the proteasome. The role of monoubiquitination is less understood, although a function in membrane trafficking is emerging, at least in yeast. Here we report that a short amino-acid stretch at the carboxy-termini of the monoubiquitinated endocytic proteins Eps15 and eps15R is indispensable for their monoubiquitination. A similar sequence, also required for this modification, is found in other cytosolic endocytic proteins, such as epsins and Hrs. These sequences comprise a protein motif, UIM (ref. 6), which has been proposed to bind to ubiquitin. We confirm this for the UIMs of eps15, eps15R, epsins and Hrs. Thus, the same motif in several endocytic proteins is responsible for ubiquitin recognition and monoubiquitination. Our results predict the existence of a UIM:ubiquitin-based intracellular network. Eps15/eps15R, epsins and Hrs may function as adaptors between ubiquitinated membrane cargo and either the clathrin coat or other endocytic scaffolds. In addition, through their own ubiquitination, they may further contribute to the amplification of this network in the endocytic pathway.     

An asymptotic-giant-branch star in the progenitor system of a type Ia supernova

Stars that explode as supernovae come in two main classes. A type Ia supernova is recognized by the absence of hydrogen and the presence of elements such as silicon and sulphur in its spectrum; this class of supernova is thought to produce the majority of iron-peak elements in the Universe. They are also used as precise 'standard candles' to measure the distances to galaxies. While there is general agreement that a type Ia supernova is produced by an exploding white dwarf star, no progenitor system has ever been directly observed. Significant effort has gone into searching for circumstellar material to help discriminate between the possible kinds of progenitor systems, but no such material has hitherto been found associated with a type Ia supernova. Here we report the presence of strong hydrogen emission associated with the type Ia supernova SN2002ic, indicating the presence of large amounts of circumstellar material. We infer from this that the progenitor system contained a massive asymptotic-giant-branch star that lost several solar masses of hydrogen-rich gas before the supernova explosion.     

HIV-1 Nef intersects the macrophage CD40L signalling pathway to promote resting-cell infection

All primate lentiviruses (HIV-1, HIV-2, SIV) encode Nef proteins, which are important for viral replication and pathogenicity in vivo. It is not known how Nef regulates these processes. It has been suggested that Nef protects infected cells from apoptosis and recognition by cytotoxic T lymphocytes. Other studies suggest that Nef influences the activation state of the infected cell, thereby enhancing the ability of that cell to support viral replication. Here we show that macrophages that express Nef or are stimulated through the CD40 receptor release a paracrine factor that renders T lymphocytes permissive to HIV-1 infection. This activity requires the upregulation of B-cell receptors involved in the alternative pathway of T-lymphocyte stimulation. T lymphocytes stimulated through this pathway become susceptible to viral infection without progressing through the cell cycle. We identify two proteins, soluble CD23 and soluble ICAM, that are induced from macrophages by Nef and CD40L, and which mediate their effects on lymphocyte permissivity. Our results reveal a mechanism by which Nef expands the cellular reservoir of HIV-1 by permitting the infection of resting T lymphocytes.