This article focuses on the housing issues of rural migrants arising from urbanization, with particular reference to "chengzhongcun", a topic with considerable impact on policymaking. An attempt is made to understand the underlying rationale of self-help in housing and the important role of chengzhongcun in sheltering rural migrants in the context of China's rural-urban dichotomy. As demonstrated in this study, chengzhongcun accommodate, with little in the way of government resources and assistance, millions of rural migrants because of their social accessibility and affordability. While not denying their social problems, we argue that chengzhongcun in fact act as an innovative and positive agent to promote urbanization in present day China by housing massive numbers of rural migrants and assimilating them into cities. Current government policies towards chengzhongcun have generated a wide range of interest conflicts and confrontations. The consequences of such conflicts show that the government policies were problematic and unworkable, as they violated basic market principles as well as citizen rights. Policy strategy towards the redevelopment of chengzhongcun must acknowledge their credibility in the Chinese road to urbanization and requires more thoughtful and prudent consideration of migrants' demands for affordable housing. Copyright (c) Joint Editors and Blackwell Publishing Ltd 2003.

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The cell is constructed by higher-order structures and organelles through complex interactions among distinct structural constituents. The centrosome is a membraneless organelle composed of two microtubule-derived structures called centrioles and an amorphous mass of pericentriolar material. Super-resolution microscopic analyses in various organisms revealed that diverse pericentriolar material proteins are concentrically localized around a centriole in a highly organized manner. However, the molecular nature underlying these organizations remains unknown. Here we show that two human pericentriolar material scaffolds, Cep63 and Cep152, cooperatively generate a heterotetrameric α-helical bundle that functions in conjunction with its neighboring hydrophobic motifs to self-assemble into a higher-order cylindrical architecture capable of recruiting downstream components, including Plk4, a key regulator for centriole duplication. Mutations disrupting the self-assembly abrogate Plk4-mediated centriole duplication. Because pericentriolar material organization is evolutionarily conserved, this work may offer a paradigm for investigating the assembly and function of centrosomal scaffolds in various organisms.

Electronic structures of graphene oxide (GO) and hydro-thermally reduced graphene oxides (rGOs) processed at low temperatures (120–180°C) were studied using X-ray absorption near-edge structure (XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). C K-edge XANES spectra of rGOs reveal that thermal reduction restores C = C sp2 bonds and removes some of the oxygen and hydroxyl groups of GO, which initiates the evolution of carbonaceous species. The combination of C K-edge XANES and Kα XES spectra shows that the overlapping π and π* orbitals in rGOs and GO are similar to that of highly ordered pyrolytic graphite (HOPG), which has no band-gap. C Kα RIXS spectra provide evidence that thermal reduction changes the density of states (DOSs) that is generated in the π-region and/or in the gap between the π and π* levels of the GO and rGOs. Two-dimensional C Kα RIXS mapping of the heavy reduction of rGOs further confirms that the residual oxygen and/or oxygen-containing functional groups modify the π and σ features, which are dispersed by the photon excitation energy. The dispersion behavior near the K point is approximately linear and differs from the parabolic-like dispersion observed in HOPG.

Tight control of centriole duplication is critical for normal chromosome segregation and the maintenance of genomic stability. Polo-like kinase 4 (Plk4) is a key regulator of centriole biogenesis. How Plk4 dynamically promotes its symmetry-breaking relocalization and achieves its procentriole-assembly state remains unknown. Here we show that Plk4 is a unique kinase that utilizes its autophosphorylated noncatalytic cryptic polo-box (CPB) to phase separate and generate a nanoscale spherical condensate. Analyses of the crystal structure of a phospho-mimicking, condensation-proficient CPB mutant reveal that a disordered loop at the CPB PB2-tip region is critically required for Plk4 to generate condensates and induce procentriole assembly. CPB phosphorylation also promotes Plk4’s dissociation from the Cep152 tether while binding to downstream STIL, thus allowing Plk4 condensate to serve as an assembling body for centriole biogenesis. This study uncovers the mechanism underlying Plk4 activation and may offer strategies for anti-Plk4 intervention against genomic instability and cancer.

Zhao S. X. B. and Zhang L. (2007) Foreign Direct Investment and the formation of global city-regions in China, Regional Studies 41, 979-994. FDI inflows have redrawn the map of China's geo-economy, reinforcing spatial clustering of economy. Currently, certain Chinese urbanized regions along the Pacific coast, notably the Pearl River Delta region (PRD) in South China, the Yangtze River Delta region (YRD) in Southeast China and the Bohai Rim region (BRR) in North China, have become the agglomerative centres for a variety of the Fordist-style of manufacturing operation. As a strong outward linkage is the major engine of growth in those extended metropolitan regions, they are often labelled as global city-regions. This paper attempts to provide a more comprehensive explanation of the questions about how global city-regions have come into being and what processes have interacted to produce global city-regions in China, focusing on the period shortly before and after China's accession into the WTO. After reviewing the extant theoretical perspectives, this paper attempts to construct the trajectory of Chinese global city-region growth based mainly on empirically derived knowledge on FDI in China with investigation on both external and internal dynamics. Zhao S. X. B. et Zhang L. (2007) L'investissement direct etranger et l'etablissement de cites-regions mondiales en Chine, Regional Studies 41, 979-994. L'afflux d'IDE a redessine la carte geo-economique de la Chine, renforcant l'agglomeration geographique de son economie. A l'heure qu'il est, certaines regions urbanisees de la Chine situees le long de la cote du Pacifique, notamment la region du Pearl River Delta (PRD) dans la Chine du Sud, la region du Yangtze River Delta (YRD) dans la Chine du Sud-Est, et la region de la Bohai Rim (BRR) dans la Chine du Nord, sont devenues les centres d'agglomeration pour toute une serie d'activites industrielles du type fordiste. Etant donne que des liens externes s'averent la force motrice de la croissance dans ces zones metropolitaines etendues, ces dernieres sont souvent classees comme cites-regions mondiales. Cet article cherche a fournir une explication plus detaillee des origines des cites-regions mondiales et des actions reciproques qui ont vu naitre les cites-regions en Chine, portant sur la periode juste avant et apres l'adhesion de la Chine a l'OMC. Apres avoir fait la critique des apercus theoriques existants, on cherche a dessiner le chemin de la croissance des cites-regions en Chine, principalement a partir des connaissances empiriques a propos de l'IDE en Chine, tout en examinat a la fois les dynamiques externe et interne. IDE Cites-regions mondiales OMC Chine Zhao S. X. B. und Zhang L. (2007) Auslandische Direktinvestitionen und die Entstehung globaler Stadtregionen in China, Regional Studies 41, 979-994. Durch den Zufluss von auslandischen Direktinvestitionen hat sich das Bild der chinesischen Geookonomie gewandelt und die raumliche Clusterbildung in der Wirtschaft verstarkt. Heute sind in China bestimmte urbanisierte ...

Dibenzothiophene (DBT) is a typical sulfur-containing compound found in fossil fuels. This compound and its derivatives are resistant to the hydrodesulfurization method often used in industry, but they are susceptible to enzymatic desulfurization via the 4S pathway, which is a well-studied biochemical pathway consisting of four enzymes. DBT monooxygenase (DszC) from Rhodococcus erythropolis is involved in the first step of the 4S pathway. We determined the crystal structure of DszC, which reveals that, in contrast to several homologous proteins, the C-terminus (410-417) of DszC participates in the stabilization of the substrate-binding pocket. Analytical ultracentrifugation analysis and enzymatic assays confirmed that the C-terminus is important for the stabilization of the active conformation of the substrate-binding pocket and the tetrameric state. Therefore, the C-terminus of DszC plays a significant role in the catalytic activity of this enzyme.

The electronic structure and band dispersion of graphene on SiO2 have been studied by X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). Using first-principles calculations, it is found that the core-hole effect is dramatic in XAS while it has negligible consequences in XES. Strong dispersive features, due to the conservation of crystal momentum are observed in RIXS spectra. Simulated RIXS spectra based on the Kramers-Heisenberg theory agree well with the experimental results, provided a shift between RIXS and XAS due to the absence/presence of the core hole is taken into account.