574 research outputs found

    Biphenyl-3,3′-dicarb­oxy­lic acid

    Get PDF
    The asymmetric unit of the title compound, C14H10O4, contains one half mol­ecule, the complete mol­ecule being generated by a twofold axis. The two benzene rings form a dihedral angle of 43.11 (5)°. Inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into one-dimensional zigzag chains. These chains are further connected into two-dimensional supra­molecular layers by weak π–π stacking inter­actions between neighbouring benzene rings, with centroid–centroid distances of 3.7648 (8) Å

    Three-Dimensional (3D) Bicontinuous Hierarchically Porous Mn2O3 Single Crystals for High Performance Lithium-Ion Batteries.

    Get PDF
    Bicontinuous hierarchically porous Mn2O3 single crystals (BHP-Mn2O3-SCs) with uniform parallelepiped geometry and tunable sizes have been synthesized and used as anode materials for lithium-ion batteries (LIBs). The monodispersed BHP-Mn2O3-SCs exhibit high specific surface area and three dimensional interconnected bimodal mesoporosity throughout the entire crystal. Such hierarchical interpenetrating porous framework can not only provide a large number of active sites for Li ion insertion, but also good conductivity and short diffusion length for Li ions, leading to a high lithium storage capacity and enhanced rate capability. Furthermore, owing to their specific porosity, these BHP-Mn2O3-SCs as anode materials can accommodate the volume expansion/contraction that occurs with lithium insertion/extraction during discharge/charge processes, resulting in their good cycling performance. Our synthesized BHP-Mn2O3-SCs with a size of ~700 nm display the best electrochemical performance, with a large reversible capacity (845 mA h g(-1) at 100 mA g(-1) after 50 cycles), high coulombic efficiency (>95%), excellent cycling stability and superior rate capability (410 mA h g(-1) at 1 Ag(-1)). These values are among the highest reported for Mn2O3-based bulk solids and nanostructures. Also, electrochemical impedance spectroscopy study demonstrates that the BHP-Mn2O3-SCs are suitable for charge transfer at the electrode/electrolyte interface.This work was realized in the frame of a program for Changjiang Scholars and Innovative Research Team (IRT1169) of the Chinese Ministry of Education. B. L. Su acknowledges the Chinese Central Government for an “Expert of the State” position in the Program of the “Thousand Talents”. Y. Li acknowledges Hubei Provincial Department of Education for the “Chutian Scholar” program. T. Hasan acknowledges funding from a Royal Academy of Engineering Research Fellowship and EPSRC IAA Grant (GRASS). This work is also financially supported by the Ph.D. Programs Foundation of Ministry of Education of China (20120143120019), This work is also financially supported by Hubei Provincial Natural Science Foundation (2014CFB160) and Self-determined and Innovative Research Funds of the SKLWUT (2015-ZD-7). We thank J.L. Xie, X.Q. Liu and T.T. Luo for TEM analysis from the Research and Test Center of Materials, Prof. L.Q. Mai for EIS analysis from WUT-Harvard Joint Nano Key Laboratory at Wuhan University of Technology.This is the final version of the article. It first appeared from NPG via http://dx.doi.org/10.1038/srep1468

    Chemometry use in the evaluation of the sanya bay water quality

    Get PDF
    No presente estudo foi realizada a identificação dos efeitos antropogênicos e das características naturais marinhas das águas da Baía de Sanya, situada ao sul do Mar da China, através de método quimiométrico. A análise de componentes principais (PCA) aplicada aos dados extraiu quatro eixos que explicaram 85,52% da variância total dos dados. Através das análises de Agrupamento e PCA foram identificados três padrões diferentes de qualidade das águas, baseados nos efeitos antropogênicos e nas características marinhas: Grupo I, localizado nas partes externa e mediana da baía; Grupo II, próximo do centro urbano de Sanya; Grupo III, localizado no estuário do Rio Sanya. Quanto ao padrão temporal, as referidas análises distinguiram uma estação seca, de novembro a abril, e uma estação chuvosa, de maio a outubro, relacionadas ao clima e características naturais. Foi visto que tanto a fonte poluidora externa, representada pelo Rio Sanya, quanto as águas do Mar do Sul da China influenciam a qualidade das águas da Baía de Sanya. Esses resultados podem ser relevantes quando considerados sob o ponto de vista do desenvolvimento socioeconômico e de saúde humana dessa região.In this study, chemometric method is employed to identify anthropogenic effects on the water quality in Sanya Bay, South China Sea, and its marine and natural characteristics. Principal component analysis has extracted the four latent factors, thus explaining 85.52% of the total variance. Cluster analysis and principal component analysis have identified three different patterns of water quality based on anthropogenic effects and marine characteristics: Cluster I located in the outer and middle parts of the bay, Cluster II close to downtown Sanya, Cluster III located in the Sanya River estuary. In terms of the temporal pattern, principal component analysis and cluster analysis have distinguished the dry season from November to the following April, and the rainy season from May to October. The temporal pattern is related to climate and natural characteristics. The similarity index between variables and scores of samples can further distinguish the contribution of the variables to the samples. Both the polluting sources external to the Sanya River and the water from the South China Sea exercise an important influence on the water quality in Sanya Bay. These results may be valuable for socioeconomic development and human health in the Sanya Bay area

    Impact of Water Scarcity on the Fenhe River Basin and Mitigation Strategies

    Get PDF
    This study produced a drought map for the Fenhe River basin covering the period from 150 BC to 2012 using regional historical drought records. Based on meteorological and hydrological features, the characteristics and causes of water scarcity in the Fenhe River basin were examined, along with their impact on the national economy and ecological environment. The effects of water scarcity in the basin on the national economy were determined from agricultural, industrial, and domestic perspectives. The impact on aquatic ecosystems was ascertained through an evolution trend analysis of surface water systems, including rivers, wetlands, and slope ecosystems, and subterranean water systems, including groundwater and karst springs. As a result of these analyses, strategies are presented for coping with water scarcity in this basin, including engineering countermeasures, such as the construction of a water network in Shanxi, and the non-engineering approach of groundwater resource preservation. These comprehensive coping strategies are proposed with the aim of assisting the prevention and control of water scarcity in the arid and semi-arid areas of China

    Expression of indoleamine 2,3-dioxygenase in nasopharyngeal carcinoma impairs the cytolytic function of peripheral blood lymphocytes

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Tumor-specific cytotoxic T cells and infiltrating lymphocytes are frequently found in tumor tissues in patients with nasopharyngeal carcinoma (NPC). Most patients with NPC, however, especially those with advanced stages, have a poor clinical prognosis despite conventional immunotherapy. The aim of this work was to examine the effect of indoleamine 2,3-dioxygenase (IDO), an immunosuppressive enzyme, on the lymphocyte function in NPC.</p> <p>Methods</p> <p>The NPC cell line CNE2 was treated by interferon-γ (IFNγ) and the levels of IDO expression was analyzed by Western blotting and reverse phase high-performance liquid chromatography (HPLC). Lymphocytes from health human exposed to the milieu created by IDO-positive CNE2 cells and the lymphocyte cytotoxicity to target tumor cells was analyzed by standard lactate dehydrogenase (LDH) release assay. Additionally, expression of IDO was determined by Immunohistochemical assay in the tumor tissues form clinically evaluated NPC.</p> <p>Results</p> <p>IDO expression was acutely induced in the NPC cell line CNE2 by low dose interferon-γ (IFNγ) or by co-incubation with activated lymphocytes. Exposure to the milieu created by IDO-positive CNE2 cells did not promote lymphocyte death, but lymphocyte cytotoxicity against target tumor cells was impaired. The suppression of lymphocyte cytotoxic function was fully restored when the conditioned medium was replaced by fresh medium for 24 h. In additionally, the IDO-positive cells were found scattered in the tumor tissues from patients with NPC.</p> <p>Conclusion</p> <p>Altogether, these findings suggest that IDO-mediated immunosuppression may be involved in the tumor immune evasion, and that blocking IDO activity in tumor cells may help to re-establish an effective anti-tumor T cell response in NPC.</p
    corecore