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Sample records for visible light-driven nicotinamide

  1. Eosin Y-sensitized artificial photosynthesis by highly efficient visible-light-driven regeneration of nicotinamide cofactor.

    Science.gov (United States)

    Lee, Sahng Ha; Nam, Dong Heon; Kim, Jae Hong; Baeg, Jin-Ook; Park, Chan Beum

    2009-07-06

    Dye-sensitized photosynthesis: Eosin Y (EY), a dye photosensitizer, works efficiently as a molecular photoelectrode by catalyzing the visible-light-driven electron-transfer reaction for efficient regeneration of NADH through a photosensitizer-electron relay dyad. Injection of the photosensitized electron resulted in highly accelerated regeneration of NADH, which can be used by glutamate dehydrogenase for the photosynthesis of L-glutamate.

  2. Visible light driven plasmonic photochemistry on nano-textured silver.

    Science.gov (United States)

    Walia, Jaspreet; Guay, Jean-Michel; Krupin, Oleksiy; Variola, Fabio; Berini, Pierre; Weck, Arnaud

    2017-12-20

    Plasmon assisted generation of silver sulfate from dodecanethiol is demonstrated on a nano-textured silver substrate with a strong surface plasmon resonance in the visible range. The observed photo-physical processes are attributed to hot charge carriers that are generated from the excitation of surface plasmon resonances using 532 nm laser light. Excited charge carriers are responsible for cleaving the alkane chain, and for generating reactive oxygen species which rapidly photooxidize the exposed sulfur atoms. The ability to drive photochemical reactions with photon energies in the visible range rather than in the UV, on nano-textured silver surfaces, will enable researchers to study photochemical transformations for a wide variety of applications. The strong optical absorbance across the visible range, combined with the fact that the substrates can be fabricated over large areas, naturally makes them candidates for solar driven photochemical applications, and for large scale plasmonic reactors.

  3. Recent advancements in plasmon-enhanced visible light-driven water splitting

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    Qingzhe Zhang

    2017-03-01

    Full Text Available Recently, the combination of plasmonic noble metallic nanostructures with semiconductors for plasmon-enhanced visible light-driven water splitting (WS has attracted considerable attention. This review first presents three prime enhancement mechanisms for plasmon-enhanced photocatalytic WS, and then some state-of-the-art representative studies are introduced according to different enhancement mechanisms. Furthermore, the design parameters of plasmonic-metal/semiconductor photocatalysts are discussed in detail, focusing on the effect of shape, size and geometric position of metallic nanostructures on the photocatalytic activity of visible light-driven WS. Finally, the challenges and perspectives for plasmon-enhanced solar WS are proposed.

  4. Preparation and characterization of visible light-driven AgCl/PPy photocatalyst

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    Gu Shuna; Li Bing [Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao Chongjun, E-mail: chongjunzhao@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Xu Yunlong; Qian Xiuzhen; Chen, Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2011-05-05

    Graphical abstract: AgCl/PPy composite exhibits improved photocatalytic performance and high stability under visible light. Display Omitted Highlights: > AgCl/(PPy) nanocomposites as visible light driven photocatalyst. > Composites exhibited high visible light-driven photocatalytic activity and stability. > Photocatalytic process on MO followed photoreduction mechanisms. > Used photocatalyst can be regenerated in aqueous FeCl{sub 3} solution. - Abstract: Visible light photoactive AgCl/polypyrrole (PPy) composites were prepared via the reaction between excessive Ag{sup +} and Cl{sup -} ions in the presence of PPy{sub .} The AgCl/PPy composites were systematically characterized using Fourier transform infrared (FTIR) spectroscopy, Raman spectra, X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and Thermal gravity analysis (TGA). It was found that face-centered cubic AgCl nanocrystallite and 0.2 wt% PPy component existed in the composite and spherical AgCl/PPy nanoparticles were in the range of 200-600 nm. The AgCl/PPy composites showed higher visible light-driven photocatalytic activity and stability than that of AgCl. A photoreduction mechanism was postulated for AgCl/PPy photocatalyst on dye methyl orange (MO). The used AgCl/PPy photocatalyst was facilely regenerated by an oxidation process in aqueous FeCl{sub 3} solution.

  5. [Degrading anticancer drugs in the medical environment using a visible light-driven photocatalyst].

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    Sato, Junya; Kikuchi, Satomi; Kudo, Kenzo

    2014-01-01

      Occupational exposure to anticancer drugs is recognized as a risk for healthcare workers. Reducing anticancer drugs in the environment is important to prevent the exposure of individuals to anticancer drugs. However, there are currently no effective degrading agents for all anticancer drugs used in clinical settings. We previously reported the resolution of an anticancer drug with the use of a photocatalyst (TiO2), which acts by absorbing ultraviolet light to degrade organic compounds. In this study, we evaluated anticancer drug degradation using a visible light-driven photocatalyst (Cu/WO3). Anticancer drugs [cyclophosphamide (CPA), paclitaxel (PTX), methotrexate (MTX), irinotecan (CPT-11), cytarabine (Ara-C), and 5-fluorouracil (5-FU)], were experimentally deposited on a stainless steel plate. The visible light-driven photocatalytic agent (0.075% Cu/WO3 solution) was sprayed onto the plate, and the plate was then left under a fluorescent lamp for 12 h. The anticancer drugs remaining on the plate were assayed by high-performance liquid chromatography (HPLC). CPA, PTX, MTX, CPT-11, Ara-C, and 5-FU were found to be degraded by up to 37.7%, >99.0%, 57.1%, 54.6%, 69.5%, and 36.3%, respectively. The visible light-driven photocatalyst was therefore confirmed to degrade anticancer drugs under a fluorescent lamp. The ability of the visible light-driven photocatalyst to degrade multiple chemotherapeutic agents without the need for altering the light source could make it a useful tool for reducing anticancer drug pollution in clinical settings.

  6. Efficient ZnO-based visible-light-driven photocatalyst for antibacterial applications.

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    Kumar, Raju; Anandan, Srinivasan; Hembram, Kaliyan; Rao, Tata Narasinga

    2014-08-13

    Herein, we report the development of a ZnO-based visible-light-driven photocatalyst by interfacial charge transfer process for the inactivation of pathogens under visible-light illumination. Surface modification by a cocatalyst on ZnO, prepared by flame spray pyrolysis process is carried out to induce the visible-light absorption in ZnO. Optical studies showed that surface modification of Cu(2+) induces the visible-light absorption in ZnO by interfacial charge transfer between ZnO and surface Cu(2+) ions upon light irradiation. The photocatalytic efficiency of pure and modified ZnO is evaluated for the inactivation of pathogens and the decomposition of methylene blue under visible-light illumination. The antibacterial activity of Cu(2+)-ZnO is several orders higher than pure ZnO and commercial Degussa-P25 and comparable with Cu(2+)-TiO2. Cu(2+)-ZnO nanorods show better photocatalytic activity than Cu(2+)-ZnO nanosphere, which is attributed to high surface area to volume ratio of former than later. The holes generated in the valence band and the Cu(1+) species generated during the interfacial charge transfer process may attribute for the inactivation of bacteria, whereas the strong oxidation power of hole is responsible for the decomposition of methylene blue. Besides the advantage of Cu(2+)-modified ZnO for visible-light-assisted photocatalytic applications, the method (FSP) used for the synthesis of ZnO in the present study is attractive for commercial application because the process has potential for the production of large quantities (2-3 kg/h) of semiconductors.

  7. CdS-graphene Nanocomposite for Efficient Visible-light-driven Photocatalytic and Photoelectrochemical Applications.

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    Khan, Mohammad Ehtisham; Khan, Mohammad Mansoob; Cho, Moo Hwan

    2016-11-15

    This paper reports cadmium sulphide nanoparticles-(CdS NPs)-graphene nanocomposite (CdS-Graphene), prepared by a simple method, in which CdS NPs were anchored/decorated successfully onto graphene sheets. The as-synthesized nanocomposite was characterized using standard characterization techniques. A combination of CdS NPs with the optimal amount of two-dimensional graphene sheets had a profound influence on the properties of the resulting hybrid nanocomposite, such as enhanced optical, photocatalytic, and photo-electronic properties. The photocatalytic degradation ability of the CdS-Graphene nanocomposite was evaluated by degrading different types of dyes in the dark and under visible light irradiation. Furthermore, the photoelectrode performance of the nanocomposite was evaluated by different electrochemical techniques. The results showed that the CdS-Graphene nanocomposite can serve as an efficient visible-light-driven photocatalyst as well as photoelectrochemical performance for optoelectronic applications. The significantly enhanced photocatalytic and photoelectrochemical performance of the CdS-Graphene nanocomposite was attributed to the synergistic effects of the enhanced light absorption behaviour and high electron conductivity of the CdS NPs and graphene sheets, which facilitates charge separation and lengthens the lifetime of photogenerated electron-hole pairs by reducing the recombination rate. The as-synthesized narrow band gap CdS-Graphene nanocomposite can be used for wide range of visible light-induced photocatalytic and photoelectrochemical based applications. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Visible-Light-Driven Photocatalytic Degradation of Organic Water Pollutants Promoted by Sulfite Addition.

    Science.gov (United States)

    Deng, Wei; Zhao, Huilei; Pan, Fuping; Feng, Xuhui; Jung, Bahngmi; Abdel-Wahab, Ahmed; Batchelor, Bill; Li, Ying

    2017-11-21

    Solar-driven heterogeneous photocatalysis has been widely studied as a promising technique for degradation of organic pollutants in wastewater. Herein, we have developed a sulfite-enhanced visible-light-driven photodegradation process using BiOBr/methyl orange (MO) as the model photocatalyst/pollutant system. We found that the degradation rate of MO was greatly enhanced by sulfite, and the enhancement increased with the concentration of sulfite. The degradation rate constant was improved by 29 times in the presence of 20 mM sulfite. Studies using hole scavengers suggest that sulfite radicals generated by the reactions of sulfite (sulfite anions or bisulfite anions) with holes or hydroxyl radicals are the active species for MO photodegradation using BiOBr under visible light. In addition to the BiOBr/MO system, the sulfite-assisted photocatalysis approach has been successfully demonstrated in BiOBr/rhodamine B (RhB), BiOBr/phenol, BiOI/MO, and Bi 2 O 3 /MO systems under visible light irradiation, as well as in TiO 2 /MO system under simulated sunlight irradiation. The developed method implies the potential of introducing external active species to improve photodegradation of organic pollutants and the beneficial use of air pollutants for the removal of water pollutants since sulfite is a waste from flue gas desulfurization process.

  9. Photocatalytic Mineralization of Organic Acids over Visible-Light-Driven Au/BiVO4 Photocatalyst

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    Kanlaya Pingmuang

    2013-01-01

    Full Text Available Au/BiVO4 visible-light-driven photocatalysts were synthesized by coprecipitation method in the presence of sodium dodecyl benzene sulfonate (SDBS as a dispersant. Physical characterization of the obtained materials was carried out by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDX, UV-Vis diffuse reflectance spectroscopy (DRS and Brunauer, and Emmett and Teller (BET specific surface area measurement. Photocatalytic performances of the as-prepared Au/BiVO4 have also been evaluated via mineralizations of oxalic acid and malonic acid under visible light irradiation. XRD and SEM results indicated that Au/BiVO4 photocatalysts were of almost spherical particles with scheelite-monoclinic phase. Photocatalytic results showed that all Au/BiVO4 samples exhibited higher oxalic acid mineralization rate than that of pure BiVO4, probably due to a decrease of BiVO4 band gap energy and the presence of surface plasmon absorption upon loading BiVO4 with Au as evidenced from UV-Vis DRS results. The nominal Au loading amount of 0.25 mol% provided the highest pseudo-first-order rate constant of 0.0487 min−1 and 0.0082 min−1 for degradations of oxalic acid (C2 and malonic acid (C3, respectively. By considering structures of the two acids, lower pseudo-first-order rate constantly obtained in the case of malonic acid degradation was likely due to an increased complexity of the degradation mechanism of the longer chain acid.

  10. Hierarchical ZnO/S,N:GQD composites: Biotemplated synthesis and enhanced visible-light-driven photocatalytic activity

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    Cai, Aijun, E-mail: caiaijun80@163.com [College of Life Science and Technology, Hebei Normal University of Science & Technology, Qinhuangdao 066600 (China); College of Chemistry and Material Sciences, Hebei Normal University, Shijiazhuang 050016 (China); Wang, Xiuping, E-mail: wangxiuping0721@163.com [College of Life Science and Technology, Hebei Normal University of Science & Technology, Qinhuangdao 066600 (China); Qi, Yanling, E-mail: qyl6790@126.com [College of Life Science and Technology, Hebei Normal University of Science & Technology, Qinhuangdao 066600 (China); Ma, Zichuan, E-mail: mazc@vip.163.com [College of Chemistry and Material Sciences, Hebei Normal University, Shijiazhuang 050016 (China)

    2017-01-01

    Highlights: • ZnO/S,N:GQD composites were synthesized by using poplar leaves as biotemplates. • The composites have enhanced visible-light-driven photocatalytic activity. • The highly efficient charge separation of electron-hole pairs is achieved. • High surface areas play an important role in the photocatalysis. - Abstract: Graphene quantum dots co-doped with sulfur and nitrogen (S,N:GQDs) are successfully combined with leaf-templated ZnO nanoparticles (L-ZnO) to obtain hierarchical L-ZnO/S,N:GQD composites exhibiting highly surface area. The morphology, structure, and the visible-light-driven photocatalytic activity are investigated. Compared with non-templated ZnO/S,N:GQDs, L-ZnO/S,N:GQD composites exhibit higher photocatalytic activity for the degradation of rhodamine B under visible light irradiation. Such elevated photocatalytic activity results from two main effects: one is the highly effective charge separation in L-ZnO/S,N:GQD composites; the other is the high surface area, allowing for efficient capture of the visible light.

  11. Mechanochemically synthesized sub-5 nm sized CuS quantum dots with high visible-light-driven photocatalytic activity

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    Li, Shun; Ge, Zhen-Hua; Zhang, Bo-Ping; Yao, Yao; Wang, Huan-Chun; Yang, Jing; Li, Yan; Gao, Chao; Lin, Yuan-Hua

    2016-10-01

    We report a simple mechanochemical ball milling method for synthesizing monodisperse CuS quantum dots (QDs) with sizes as small as sub-5 nm. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The CuS QDs exhibited excellent visible-light-driven photocatalytic activity and stability for degradation of Rodanmine B aqueous solution as Fenton-like reagents. Our study opens the opportunity to low-cost and facile synthesis of QDs in large scale for future industrial applications.

  12. Peptide Self-Assembled Biofilm with Unique Electron Transfer Flexibility for Highly Efficient Visible-Light-Driven Photocatalysis.

    Science.gov (United States)

    Pan, Yun-Xiang; Cong, Huai-Ping; Men, Yu-Long; Xin, Sen; Sun, Zheng-Qing; Liu, Chang-Jun; Yu, Shu-Hong

    2015-11-24

    Inspired by natural photosynthesis, biomaterial-based catalysts are being confirmed to be excellent for visible-light-driven photocatalysis, but are far less well explored. Herein, an ultrathin and uniform biofilm fabricated from cold-plasma-assisted peptide self-assembly was employed to support Eosin Y (EY) and Pt nanoparticles to form an EY/Pt/Film catalyst for photocatalytic water splitting to H2 and photocatalytic CO2 reduction with water to CO, under irradiation of visible light. The H2 evolution rate on EY/Pt/Film is 62.1 μmol h(-1), which is about 5 times higher than that on Pt/EY and 1.5 times higher than that on the EY/Pt/TiO2 catalyst. EY/Pt/Film exhibits an enhanced CO evolution rate (19.4 μmol h(-1)), as compared with Pt/EY (2.8 μmol h(-1)) and EY/Pt/TiO2 (6.1 μmol h(-1)). The outstanding activity of EY/Pt/Film results from the unique flexibility of the biofilm for an efficient transfer of the photoinduced electrons. The present work is helpful for designing efficient biomaterial-based catalysts for visible-light-driven photocatalysis and for imitating natural photosynthesis.

  13. Immobilization of TiO2 Nanoparticles on Chlorella pyrenoidosa Cells for Enhanced Visible-Light-Driven Photocatalysis

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    Aijun Cai

    2017-05-01

    Full Text Available TiO2 nanoparticles are immobilized on chlorella cells using the hydrothermal method. The morphology, structure, and the visible-light-driven photocatalytic activity of the prepared chlorella/TiO2 composite are investigated by various methods. The chlorella/TiO2 composite is found to exhibit larger average sizes and higher visible-light intensities. The sensitization of the photosynthesis pigment originating from chlorella cells provides the anatase TiO2 with higher photocatalytic activities under the visible-light irradiation. The latter is linked to the highly efficient charge separation of the electron/hole pairs. The results also suggest that the photocatalytic activity of the composite remains substantial after four cycles, suggesting a good stability.

  14. Mechanochemically synthesized sub-5 nm sized CuS quantum dots with high visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shun; Ge, Zhen-Hua [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Bo-Ping, E-mail: bpzhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Yao, Yao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Huan-Chun [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Yang, Jing; Li, Yan; Gao, Chao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Lin, Yuan-Hua [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China)

    2016-10-30

    Highlights: • CuS quantum dots (<5 nm) were synthesized by mechanochemical ball milling. • Defects was observed in the CuS quantum dots. • They show good visible light photocatalytic activity as Fenton-like reagents. - Abstract: We report a simple mechanochemical ball milling method for synthesizing monodisperse CuS quantum dots (QDs) with sizes as small as sub-5 nm. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The CuS QDs exhibited excellent visible-light-driven photocatalytic activity and stability for degradation of Rodanmine B aqueous solution as Fenton-like reagents. Our study opens the opportunity to low-cost and facile synthesis of QDs in large scale for future industrial applications.

  15. Biochemical Synthesis of Ag/AgCl Nanoparticles for Visible-Light-Driven Photocatalytic Removal of Colored Dyes

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    Xiyun Zhao

    2015-04-01

    Full Text Available Photocatalytic removal of organic pollution such as waste colored dyes was a promising technique for environment technique. However, effective photocatalysts were needed to enhance the photocatalytic efficiency. Ag/AgCl was regarded as high performance catalyst for photocatalytic degradation. Ag/AgCl nanoparticles were biochemically prepared with metabolin of living fungi which was used as reductant and characterized by X-Ray diffraction (XRD, UV-visible spectroscopy and transmission electron microscopy (TEM. The Ag/AgCl nanoparticle composites showed spherical aggregation shape with an average size of about 3–5 nm which is well inside the quantum regime. The UV-visible study showed that Ag/AgCl nanoparticles had strong visible light absorption and exhibited excellent visible-light-driven photocatalytic performance. Photocatalytic results indicated that the obtained Ag/AgCl nanoparticles were suitable for photocatalytic removal of RhB dye under visible light irradiation. The excellent photocatalytic activities could be attributed to the quantum size nanoparticles and the Plasmon resonance of Ag/AgCl composites.

  16. Light-Driven Preparation, Microstructure, and Visible-Light Photocatalytic Property of Porous Carbon-Doped TiO2

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    Xiao-Xin Zou

    2012-01-01

    Full Text Available Highly porous carbon-doped TiO2 (C-TiO2 has been prepared, for the first time, through a light-driven approach using crystalline titanium glycolate (TG as the single-source precursor. Although the nonthermally prepared porous C-TiO2 is amorphous, it shows a remarkable visible-light photocatalytic activity higher than that of nitrogen-doped TiO2 (N-TiO2 due to its significant surface area (530 m2/g and pore-rich structure. X-ray photoelectron, electron paramagnetic resonance, and UV-Vis diffuse reflectance spectroscopy reveal that the as-prepared porous C-TiO2 photocatalyst contains Ti–O–C bonds which result in visible-light absorption of the material at wavelengths less than 550 nm. Furthermore, it is discovered that the Ti–O–C bonds in the as-prepared C-TiO2 is easily transformed to coke-type species under mild thermal treatment (200°C. The resulting coke-containing porous TiO2 is an even better visible-light photocatalyst, almost twice as effective as N-TiO2, because of its stronger visible-light absorption. The Ti–O–C and the coke-containing porous TiO2 materials follow two different mechanisms in the visible-light photocatalysis process for degradation of methylene blue.

  17. Quick and facile preparation of visible light-driven TiO2 photocatalyst with high absorption and photocatalytic activity.

    Science.gov (United States)

    Yang, Yucheng; Zhang, Ting; Le, Ling; Ruan, Xuefeng; Fang, Pengfei; Pan, Chunxu; Xiong, Rui; Shi, Jing; Wei, Jianhong

    2014-11-13

    Self-doping TiO2 has recently attracted considerable attention for its high photocatalytic activity under visible-light irradiation. However, the literature reported synthetic methods until now were very time-consuming. In this study, we establish a quick and facile method for obtaining self-doping TiO2 with the use of directly treated commercial P25 at a desired temperature for only 5 min through spark plasma sintering technology. With the using of this method, the modified P25 samples exhibit significantly high photoelectric and photocatalytic performance. Furthermore, the sample prepared at 600 °C exhibits the optimum catalytic activity. The photodegradation and H2 evolution rates of this samples are significantly higher than those of unmodified P25 sample under visible-light irradiation. The physical origin of the visible-light absorption for the modified P25 samples is investigated in detail according to their structural, optical, and electronic properties. This work will provide a quick and facile method for the large-scale synthesis of visible-light driven photocatalyst for practical applications.

  18. xBiOI-(1 - x)BiOCl as efficient visible-light-driven photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wendeng [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Huang Fuqiang [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: huangfq@mail.sic.ac.cn; Lin Xinping [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2007-04-15

    A new class of oxyhalide photocatalysts, xBiOI-(1 - x)BiOCl, were prepared by a soft chemical method. The samples with x = 0.2-1.0 have intense absorptions in the visible light region and the optical band gaps are in the range 1.92-2.31 eV. They possess high photocatalytic activities under visible light irradiation for the degradation of methyl orange. This high photocatalytic activity is in close relation with the deep valance band edge position and the internal electric fields between [Bi{sub 2}O{sub 2}] slabs and halogen anionic slabs.

  19. Visible light driven multifunctional photocatalysis in TeO2-based semiconductor glass ceramics

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    Kushwaha, Himmat Singh; Thomas, Paramanandam; Vaish, Rahul

    2017-01-01

    Photocatalytic xCaCu3Ti4O12-(100-x)TeO2 (x=0.25 mol% to 3 mol%), glass nanocomposites were fabricated and investigated for wastewater treatment, self-cleaning surfaces, and photocatalytic hydrogen evolution. Visible light active crystals of Cu-doped TiO2 and TiTe3O8 were grown by optimized crystallization of as-quenched glasses. The visible light photocatalytic activity of glass samples was investigated for estrogenic pharmaceutical pollutants, and the degradation rate was obtained as 168.56 min-1 m-2. A higher photocatalytic H2 production rate was observed (135 μmole h-1 g-1) for the crystallized CaCu3Ti4O12-TeO2 (x=3. 0) glass plate under visible light. The self-cleaning performance was observed using contact angle measurements for water under dark and light conditions. These visible light active glass ceramics are a cost effective sustainable solution for water treatment and self-cleaning applications.

  20. Hydrothermal Preparation of Visible-Light-Driven N-Br-Codoped TiO2 Photocatalysts

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    Yonggang Sheng

    2008-01-01

    Full Text Available Using a facile hydrothermal method, N-Br-codoped TiO2 photocatalyst that had intense absorption in visible region was prepared at low temperature (100°C, through a direct reaction between nanocrystalline anatase TiO2 solution and cetyltrimethylammonium bromide (CTAB. The results of X-ray photoelectron spectroscopy (XPS showed the existence of N-Ti-N, O-Ti-N-R, Ti3+ (attribute to the doped Br atoms by charge compensation, and TiOxNy species, indicating the successful codoping of N and Br atoms, which were substituted for lattice oxygen without any influence on the crystalline phase of TiO2. In contrast to the N-doped sample, the N-Br-codoped TiO2 photocatalyst could more readily photodegrade methylene blue (MB under visible-light irradiation. The visible-light catalytic activity of thus-prepared photocatalyst resulted from the synergetic effect of the doped nitrogen and bromine, which not only gave high absorbance in the visible-light range, but also reduced electron-hole recombination rate.

  1. Template synthesis of Ag/AgCl microrods and their efficient visible light-driven photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hua; Xiao, Liang; Huang, Jianhua, E-mail: jhhuang@zstu.edu.cn

    2014-09-15

    Highlights: • Preparation ofAg/AgCl microrods by reaction of Ag{sub 2}WO{sub 4} microrods with NaCl solution. • Generation of metallic Ag is induced by the ambient light in the synthesis process. • Ag/AgCl shows excellent visible light-driven photodegradation of organic dyes. - Abstract: Ag/AgCl microrods, aggregated by nanoparticles with a diameter ranging from 100 nm to 2 μm, were prepared by an ion-exchange reaction at 80 °C between Ag{sub 2}WO{sub 4} template and NaCl solution. The existence of metallic Ag species was confirmed by XRD, DRS and XPS measurements. Ag/AgCl microrods showed excellent photocatalytic activity for the degradation of rhodamine B and methylene blue under visible light irradiation. The degradation rate constants of rhodamine B and methylene blue are 0.176 and 0.114 min{sup −1}, respectively. The cycling photodegradation experiments suggest that Ag/AgCl microds could be employed as stable plasmonic photocatalysts for the degradation of organic dyes under visible light irradiation.

  2. Hydrothermal derived nitrogen doped SrTiO3 for efficient visible light driven photocatalytic reduction of chromium(VI).

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    Xing, Guanjie; Zhao, Lanxiao; Sun, Tao; Su, Yiguo; Wang, Xiaojing

    2016-01-01

    In this work, we report on the synthesis of nitrogen doped SrTiO3 nanoparticles with efficient visible light driven photocatalytic activity toward Cr(VI) by the solvothermal method. The samples are carefully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy and photocatalytic test. It is found that nitrogen doping in SrTiO3 lattice led to an apparent lattice expansion, particle size reduction as well as subsequent increase of Brunner-Emmet-Teller surface area. The visible light absorption edge and intensity can be modulated by nitrogen doping content, which absorption edge extends to about 600 nm. Moreover, nitrogen doping can not only modulate the visible light absorption feature, but also have consequence on the enhancement of charge separation efficiency, which can promote the photocatalytic activity. With well controlled particle size, Brunner-Emmet-Teller surface area, and electronic structure via nitrogen doping, the photocatalytic performance toward Cr(VI) reduction of nitrogen doped SrTiO3 was optimized at initial hexamethylenetetramine content of 2.

  3. Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

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    Chen, Shi; Ng, Chin Fan; Huan, Cheng Hon Alfred

    2014-01-01

    Summary A facile, solvothermal synthesis of mesoporous cerium oxide nanospheres is reported for the purpose of the photocatalytic degradation of organic dyes and future applications in sustainable energy research. The earth-abundant, relatively affordable, mixed valence cerium oxide sample, which consists of predominantly Ce7O12, has been characterized by powder X-ray diffraction, X-ray photoelectron and UV–vis spectroscopy, and transmission electron microscopy. Together with N2 sorption experiments, the data confirms that the new cerium oxide material is mesoporous and absorbs visible light. The photocatalytic degradation of rhodamin B is investigated with a series of radical scavengers, suggesting that the mechanism of photocatalytic activity under visible-light irradiation involves predominantly hydroxyl radicals as the active species. PMID:24991486

  4. Theoretical design of visible light driven azobenzene-based photo-switching molecules

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    Pang, Juan; Tian, Ziqi; Ma, Jing

    2014-10-01

    The preparation of switchable azobenzene derivatives driven by visible light is desirable for applications in biomolecular systems. o-R-substituted 4,4‧-diacetamidoazobenzene derivatives (Rdbnd H, CH3, OCH3 or OH) were investigated by using both density functional theory (DFT) and reactive molecular dynamics simulations. DFT calculations demonstrated that the nonplanar azo trans geometric structure, which caused by bulky groups tetra substituted in the ortho-position, is the key factor to enable the trans → cis transition with visible light. Furthermore, 100 independent reactive MD simulations demonstrated that 71% trans isomers of tetra o-OCH3-substituted 4,4‧-diacetamidoazobenzene translated to cis, in good agreement with the experimental data.

  5. Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

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    Subas K. Muduli

    2014-04-01

    Full Text Available A facile, solvothermal synthesis of mesoporous cerium oxide nanospheres is reported for the purpose of the photocatalytic degradation of organic dyes and future applications in sustainable energy research. The earth-abundant, relatively affordable, mixed valence cerium oxide sample, which consists of predominantly Ce7O12, has been characterized by powder X-ray diffraction, X-ray photoelectron and UV–vis spectroscopy, and transmission electron microscopy. Together with N2 sorption experiments, the data confirms that the new cerium oxide material is mesoporous and absorbs visible light. The photocatalytic degradation of rhodamin B is investigated with a series of radical scavengers, suggesting that the mechanism of photocatalytic activity under visible-light irradiation involves predominantly hydroxyl radicals as the active species.

  6. Novel GQD-PVP-CdS composite with enhanced visible-light-driven photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Tao; Li, Yinle; Shen, Jianfeng, E-mail: jfshen@fudan.edu.cn; Ye, Mingxin, E-mail: mxye@fudan.edu.cn

    2016-03-30

    Graphical abstract: - Highlights: • GQD-PVP-CdS composite was prepared for the first time through a facile hydrothermal route. • GQD-PVP-CdS demonstrated outstanding photoactivity under visible light illumination. • GQDs and polymeric material are compounded with CdS nanoparticles simultaneously for the first time. • The addition of GQDs plays pivotal roles in the enhancement of the photoactivity. - Abstract: A facile one-step hydrothermal method to synthesize graphene quantum dots (GQDs)-polyvinyl pyrrolidone (PVP)-CdS nanocomposite was reported. The nanocomposite was thoroughly characterized with X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and ultraviolet–visible spectroscopy. The results confirmed the formation of GQD-PVP-CdS composite with a uniform size (5–10 nm) and a relatively low band gap (E{sub g} = 2.23 eV). Moreover, the as-prepared composite exhibited enhanced photocatalytic activity toward the degradation of organic contaminants, with 92.3% of methyl orange (10 mg/L) removed after 3 hours of visible light illumination. This enhancement in photocatalytic activity was postulated to be attributed to the upconversion property of GQDs and a more efficient charge distribution between GQDs and CdS particles.

  7. Visible-Light-Driven Photocatalytic Activation of Inert Sulfur Ylides for 3-Acyl Oxindole Synthesis.

    Science.gov (United States)

    Xia, Xu-Dong; Lu, Liang-Qiu; Liu, Wen-Qiang; Chen, Dong-Zhen; Zheng, Yu-Han; Wu, Li-Zhu; Xiao, Wen-Jing

    2016-06-13

    Bicarbonyl-substituted sulfur ylide is a useful, but inert reagent in organic synthesis. Usually, harsh reaction conditions are required for its transformation. For the first time, it was demonstrated that a new, visible-light photoredox catalytic annulation of sulfur ylides under extremely mild conditions, permits the synthesis of oxindole derivatives in high selectivities and efficiencies. The key to its success is the photocatalytic single-electron-transfer (SET) oxidation of the inert amide and acyl-stabilized sulfur ylides to reactive radical cations, which easily proceeds with intramolecular C-H functionalization to give the final products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Flower-like BiVO4 Microspheres and Their Visible Light-Driven Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Arini Nuran Zulkifili

    2018-01-01

    Full Text Available A flower-like BiVO4 microsphere photocatalyst was synthesized with a simple template-free homogeneous precipitation method at 60 °C for 24 h. The purpose of this study is to explore a low-cost, simple method of synthesizing the self-assembled 3D structure in order to enhance photocatalytic performance under visible light irradiation (λ > 420 nm. In this study, the morphology, structure, and photo-absorption of flower-like BiVO4 microspheres were characterized, and the effects of photocatalysis were analyzed. The results indicate that the size of the flower-like microspheres was about 2 μm to 4 μm and they were composed of several nanosheets. The mechanism of hierarchical microsphere formation has been proposed as the Ostwald ripening process and the self-assembled process. The obtained samples were calcined under different temperatures (300 °C, 400 °C, 500 °C and 600 °C to study the effects of calcination on the structure and on photocatalysis. The photocatalytic process was then evaluated by decolorization of methylene blue dye under visible-light irradiation.

  9. Recent progress in oxynitride photocatalysts for visible-light-driven water splitting.

    Science.gov (United States)

    Takata, Tsuyoshi; Pan, Chengsi; Domen, Kazunari

    2015-06-01

    Photocatalytic water splitting into hydrogen and oxygen is a method to directly convert light energy into storable chemical energy, and has received considerable attention for use in large-scale solar energy utilization. Particulate semiconductors are generally used as photocatalysts, and semiconductor properties such as bandgap, band positions, and photocarrier mobility can heavily impact photocatalytic performance. The design of active photocatalysts has been performed with the consideration of such semiconductor properties. Photocatalysts have a catalytic aspect in addition to a semiconductor one. The ability to control surface redox reactions in order to efficiently produce targeted reactants is also important for photocatalysts. Over the past few decades, various photocatalysts for water splitting have been developed, and a recent main concern has been the development of visible-light sensitive photocatalysts for water splitting. This review introduces the study of water-splitting photocatalysts, with a focus on recent progress in visible-light induced overall water splitting on oxynitride photocatalysts. Various strategies for designing efficient photocatalysts for water splitting are also discussed herein.

  10. Cross-Linked Graphitic Carbon Nitride with Photonic Crystal Structure for Efficient Visible-Light-Driven Photocatalysis.

    Science.gov (United States)

    Sun, Lu; Hong, Wei; Liu, Jing; Yang, Meijia; Lin, Wensheng; Chen, Guojian; Yu, Dingshan; Chen, Xudong

    2017-12-27

    Highly cross-linked graphitic carbon nitride has been prepared by a thermal copolymerization of dicyanodiamide with tetramethylammonium salts. The cross-linking can be evidenced by (i) increased C/N ratio without new carbon species, (ii) decreased specific surface area, and (iii) Tyndall effect after dissolution in concentrated sulfuric acid. The cross-linked graphitic carbon nitride with photonic crystal structure has highly efficient photocatalytic activity for water splitting under visible light due to the synergistic enhancement by the greatly suppressed photoluminescence, red-shifted absorption edges, strong inner reflections, and effective PCs stop band overlaps. It exhibits an enhanced photodegradation kinetic of methyl orange and a high visible-light-driven hydrogen-evolution rate of 166.9 μmol h-1 (25 times higher than that of the pristine graphitic carbon nitride counterpart). This work presents a facile method for designing and developing high-performance graphitic carbon nitride photocatalysts, providing a broad range of application prospects in the fields of electronics and energy conversion.

  11. A visible-light driven Bi2S3@ZIF-8 core-shell heterostructure and synergistic photocatalysis mechanism.

    Science.gov (United States)

    Ding, Yan-Hua; Zhang, Xiao-Lei; Zhang, Na; Zhang, Jian-Yong; Zhang, Rui; Liu, Yu-Feng; Fang, Yong-Zheng

    2018-01-15

    Visible-light-driven organic transformations have received much attention because of their low cost, relative safety, and environmental friendliness. In this work, we report a series of Bi2S3@ZIF-8 core-shell heterostructures prepared using a simple and efficient self-assembly process. The photocatalytic activity was evaluated using the photocatalytic degradation of Rhodamine B (RhB) under visible-light irradiation and the results show that the core-shell Bi2S3@ZIF-8 heterostructure can remarkably enhance the photocatalytic efficiency at room temperature compared to pristine Bi2S3 nanorods. In addition, the Bi2S3@ZIF-8 composite with a Bi/Zn molar ratio of 1/10 demonstrates good structural stability after the degradation experiment and its photocatalytic activity remains at about 95% after the five recycling tests. The improved photocatalytic performance can be attributed to the larger specific surface area, increased light absorption, and more efficient separation of photogenerated electron-hole pairs due to the combined effects of Bi2S3 and ZIF-8. Moreover, the synergistic photocatalysis mechanism was investigated.

  12. The design of novel visible light driven Ag/CdO as smart nanocomposite for photodegradation of different dye contaminants

    Science.gov (United States)

    Saravanakumar, K.; Muthuraj, V.; Jeyaraj, M.

    2018-01-01

    In this paper, we report a novel visible light driven Ag/CdO photocatalyst, fabricated for the first time via one pot hydrothermal method and further applied for the photodegradation of two important exemplar water contaminants, Malachite green and Acid Orange 7. The microstructure, composition and optical properties of Ag/CdO nanocomposites were thoroughly investigated by various techniques. Scanning electron microscopy clearly shows that Ag NPs were strongly embedded between the CdO nanoparticles. Among the series of synthesized Ag/CdO nanocomposites, (5%) Ag/CdO nanocomposite possesses enhanced photocatalytic activity. This result was attributed to the synergistic effect between Ag and CdO, and mainly Ag NPs can act as an electron trap site, which could reduce the recombination of the electron-hole and induce the visible light absorption. The active species trapping experiments implicate radOH and O2rad - radicals as the respective primary and secondary reactive species responsible for oxidative photodegradation of organic pollutants. On the basis of the results, a possible photocatalytic mechanism has also been proposed.

  13. Silver Orthophosphate Immobilized on Flaky Layered Double Hydroxides as the Visible-Light-Driven Photocatalysts

    Directory of Open Access Journals (Sweden)

    Xianlu Cui

    2012-01-01

    Full Text Available Flaky layered double hydroxide (FLDH was prepared by the reconstruction of its oxide in alkali solution. The composites with FLDH/Ag3PO4 mass ratios at 1.6 : 1 and 3 : 1 were fabricated by the coprecipitation method. The powders were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscope, and UV-vis diffuse reflectance spectroscopy. The results indicated that the well-distributed Ag3PO4 in a fine crystallite size was formed on the surface of FLDH. The photocatalytic activities of the Ag3PO4 immobilized on FLDH were significantly enhanced for the degradation of acid red G under visible light irradiation compared to bare Ag3PO4. The composite with the FLDH/Ag3PO4 mass ratio of 3 : 1 showed a higher photocatalytic efficiency.

  14. Layered-Double-Hydroxide Nanosheets as Efficient Visible-Light-Driven Photocatalysts for Dinitrogen Fixation.

    Science.gov (United States)

    Zhao, Yufei; Zhao, Yunxuan; Waterhouse, Geoffrey I N; Zheng, Lirong; Cao, Xingzong; Teng, Fei; Wu, Li-Zhu; Tung, Chen-Ho; O'Hare, Dermot; Zhang, Tierui

    2017-09-28

    Semiconductor photocatalysis attracts widespread interest in water splitting, CO2 reduction, and N2 fixation. N2 reduction to NH3 is essential to the chemical industry and to the Earth's nitrogen cycle. Industrially, NH3 is synthesized by the Haber-Bosch process under extreme conditions (400-500 °C, 200-250 bar), stimulating research into the development of sustainable technologies for NH3 production. Herein, this study demonstrates that ultrathin layered-double-hydroxide (LDH) photocatalysts, in particular CuCr-LDH nanosheets, possess remarkable photocatalytic activity for the photoreduction of N2 to NH3 in water at 25 °C under visible-light irradiation. The excellent activity can be attributed to the severely distorted structure and compressive strain in the LDH nanosheets, which significantly enhances N2 chemisorption and thereby promotes NH3 formation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Carbon nitride-TiO2 hybrid modified with hydrogenase for visible light driven hydrogen production.

    Science.gov (United States)

    Caputo, Christine A; Wang, Lidong; Beranek, Radim; Reisner, Erwin

    2015-10-01

    A system consisting of a [NiFeSe]-hydrogenase (H2ase) grafted on the surface of a TiO2 nanoparticle modified with polyheptazine carbon nitride polymer, melon (CN x ) is reported. This semi-biological assembly shows a turnover number (TON) of more than 5.8 × 105 mol H2 (mol H2ase)-1 after 72 h in a sacrificial electron donor solution at pH 6 during solar AM 1.5 G irradiation. An external quantum efficiency up to 4.8% for photon-to-hydrogen conversion was achieved under irradiation with monochromatic light. The CN x -TiO2-H2ase construct was also active under UV-free solar light irradiation (λ > 420 nm), where it showed a substantially higher activity than TiO2-H2ase and CN x -H2ase due, in part, to the formation of a CN x -TiO2 charge transfer complex and highly productive electron transfer to the H2ase. The CN x -TiO2-H2ase system sets a new benchmark for photocatalytic H2 production with a H2ase immobilised on a noble- and toxic-metal free light absorber in terms of visible light utilisation and stability.

  16. Visible light driven overall water splitting using cocatalyst/BiVO4 photoanode with minimized bias.

    Science.gov (United States)

    Ding, Chunmei; Shi, Jingying; Wang, Donge; Wang, Zhijun; Wang, Nan; Liu, Guiji; Xiong, Fengqiang; Li, Can

    2013-04-07

    BiVO4 and many other semiconductor materials are ideal visible light responsive semiconductors, but are insufficient for overall water splitting. Upon loading water oxidation cocatalyst, for example Co-borate (denoted as CoBi) used here, onto BiVO4 photoanode, it is found that not only the onset potential is negatively shifted but also the photocurrent and the stability are significantly improved. And more importantly, PEC overall water splitting to H2 and O2 is realized using CoBi/BiVO4 as photoanode with a rather low applied bias (less than 0.3 V vs. counter electrode) in a two-electrode scheme, while at least 0.6 V is needed for bare BiVO4. This work demonstrates the practical possibility of achieving overall water splitting using the PEC strategy under a bias as low as the theoretical minimum, which is the difference between the flat band and proton reduction potential for a photoanode thermodynamically insufficient for water reduction. As long as the water oxidation overpotential is overcome with an efficient cocatalyst, the applied bias of the whole system is only used for that thermodynamically required for the proton reduction.

  17. Enhanced visible-light-driven photocatalytic performance of porous graphitic carbon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Fei, E-mail: feichang@usst.edu.cn [School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Li, Chenlu; Luo, Jieru; Xie, Yunchao; Deng, Baoqing [School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Hu, Xuefeng, E-mail: xfhu@yic.ac.cn [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003 (China)

    2015-12-15

    Graphical abstract: - Highlights: • Porous g-C{sub 3}N{sub 4} samples were fabricated by a facile pyrolysis method. • As-prepared porous g-C{sub 3}N{sub 4} samples showed remarkably enhanced photocatalytic performance. • Holes and radicals ·O{sub 2}{sup −} exerted dominant roles on the photocatalytic process. - Abstract: In this study, a series of porous graphitic carbon nitride (g-C{sub 3}N{sub 4}) materials were fabricated through a direct pyrolysis of protonated melamine by nitric acid solution. These as-prepared porous samples were characterized by a collection of analytical techniques. It was found that a proper concentration of nitric acid solution involved facilitated to generate samples in tube-like morphology with numerous pores, identified with X-ray diffraction patterns, FT-IR spectra, SEM, TEM, and BET measurements. These g-C{sub 3}N{sub 4} samples were subjected to photocatalytic degradation of dye Rhodamine B (RhB) in aqueous under visible-light irradiation. Under identical conditions, those porous g-C{sub 3}N{sub 4} samples showed significantly improved catalytic performance in comparison with the sample prepared without the introduction of nitric acid. In particularly, the best candidate, sample M1:1, showed an apparent reaction rate nearly 6.2 times that of the unmodified counterpart. The enhancement of photocatalytic performance could be attributed to the favorable porous structure with the enlarged specific surface area and the suitable electronic structure as well. In addition, ESR measurements were conducted for the sake of proposing a photocatalytic degradation mechanism.

  18. Visible-light-driven methane formation from CO2 with a molecular iron catalyst

    Science.gov (United States)

    Rao, Heng; Schmidt, Luciana C.; Bonin, Julien; Robert, Marc

    2017-08-01

    Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions. One strategy aims for electrochemical conversions powered by electricity from renewable sources, but photochemical approaches driven by sunlight are also conceivable. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare. Here we show that an iron tetraphenylporphyrin complex functionalized with trimethylammonio groups, which is the most efficient and selective molecular electro- catalyst for converting CO2 to CO known, can also catalyse the eight-electron reduction of CO2 to methane upon visible light irradiation at ambient temperature and pressure. We find that the catalytic system, operated in an acetonitrile solution containing a photosensitizer and sacrificial electron donor, operates stably over several days. CO is the main product of the direct CO2 photoreduction reaction, but a two-pot procedure that first reduces CO2 and then reduces CO generates methane with a selectivity of up to 82 per cent and a quantum yield (light-to-product efficiency) of 0.18 per cent. However, we anticipate that the operating principles of our system may aid the development of other molecular catalysts for the production of solar fuels from CO2 under mild conditions.

  19. Mussel-inspired green synthesis of polydopamine-Ag-AgCl composites with efficient visible-light-driven photocatalytic activity.

    Science.gov (United States)

    Cai, Aijun; Wang, Xiuping; Guo, Aiying; Chang, Yongfang

    2016-09-01

    Polydopamine-Ag-AgCl composites (PDA-Ag-AgCl) were synthesized using a mussel-inspired method at room temperature, where PDA acts as a reducing agent to obtain the noble Ag nanoparticles from a precursor. The morphologies and structures of the as-prepared PDA-Ag-AgCl were characterized by several techniques including field emission scanning electron microscopy (FESEM), transmission electron microscopy (SEM), Raman spectra, and X-Ray photoelectron spectrum (XPS). The morphological observation depicts formation of nanoparticles with various micrometer size diameters and surface XPS analysis shows presence of various elements including Ag, N, Cl, and O. The enhanced absorbance of the PDA-Ag-AgCl particles in the visible light region is confirmed through UV-Vis diffuse reflectance spectra (DRS), and the charge transfer is demonstrated by photoluminescence (PL) and photocurrent response. The synthesized PDA-Ag-AgCl composites could be used as visible-light-driven photocatalysts for the degradation of Rhodamine B. The elevated photocatalytic activity is ascribed to the effective charge transfer from plasmon-excited Ag to AgCl that can improve the efficiency of the charge separation during the photocatalytic reaction. Furthermore, differences in the photocatalytic performance among the different PDA-Ag-AgCl composites are noticed that could be attributed to the Brunauer-Emmett-Teller (BET) specific surface area, which benefits to capture the visible light efficiently. The PDA-Ag-AgCl exhibits excellent stability without a significant loss in activity after 5cycles. The proposed method is low-cost and environmentally friendly, hence a promising new way to fabricate plasmon photocatalysts. Copyright © 2016. Published by Elsevier B.V.

  20. Mechanistic study of the visible-light-driven photocatalytic inactivation of bacteria by graphene oxide–zinc oxide composite

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dan [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); An, Taicheng, E-mail: antc99@gig.ac.cn [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li, Guiying [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wang, Wei, E-mail: weiwang@hust.edu.cn [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Cai, Yuncheng [State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Yip, Ho Yin [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Zhao, Huijun [Centre for Clean Environment and Energy, Gold Coast Campus, Griffith University, Queensland 4222 (Australia); Wong, Po Keung, E-mail: pkwong@cuhk.edu.hk [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (China)

    2015-12-15

    Graphical abstract: - Highlights: • The GO–ZnO composites exhibited efficient VLD bacterial inactivation performance. • Strong interfacial interaction existed between GO and ZnO. • GO served as a photosensitizer in the inactivation process. • Excellent antibacterial activity by GO–ZnO composite was shown under sunlight. • An inactivation mechanism based on the GO photosensitizer induction was proposed. - Abstract: The visible-light-driven (VLD) photocatalytic activity of graphene oxide–zinc oxide (GO–ZnO) composite prepared by a simple hydrothermal method was evaluated toward the inactivation of Escherichia coli K-12. The results showed that GO–ZnO composite had excellent VLD photocatalytic bacterial inactivation activity, comparing with those of ZnO and GO, which was attributed to the strong interaction between ZnO and GO in the composite. Accordingly, an interaction induced VLD photocatalytic inactivation mechanism of the strong interaction of GO with ZnO within the GO–ZnO composite was proposed. GO served as a photosensitizer and facilitated the charge separation and transfer, thus boosted the massive production of reactive oxygen species such as ·OH{sub bulk}, which was identified as the major reactive species from conduction band of ZnO, and resulted in a remarkable enhancement of bacterial inactivation efficiency. Moreover, GO–ZnO composite showed obviously superior photocatalytic bacterial inactivation within 10 min under natural solar light irradiation, indicating that GO–ZnO composite has great potential in wastewater treatment and environmental protection.

  1. Design of a visible light driven photo-electrochemical/electro-Fenton coupling oxidation system for wastewater treatment.

    Science.gov (United States)

    Ding, Xing; Ai, Zhihui; Zhang, Lizhi

    2012-11-15

    In this study, we report on a photo-electrochemical/electro-Fenton oxidation (PEC/EF) system by coupling visible light driven photo-electrochemical oxidation (PEC) and electro-Fenton oxidation (EF) in an undivided cell. Bi2WO6 nanoplates deposited on FTO glass (Bi2WO6/FTO) and Fe@Fe2O3 core-shell nanowires supported on activated carbon fiber (Fe@Fe2O3/ACF) were used as the anode and the cathode in the PEC/EF system, respectively. This novel PEC/EF system showed much higher activity than the single PEC and EF systems on degradation of rhodamine B in aqueous solution at natural pH. Moreover, the degradation and the instantaneous current efficiencies of the PEC/EF system were increased by 154% and 26% in comparison with the sum of those of single PEC and EF systems, respectively. These significant enhancements could be attributed to the synergetic effect from better separation of photo-generated carriers in the photo-anode and the transfer of photo-electrons to the oxygen diffusion cathode to generate more electro-generated H2O2 and hydroxyl radicals on the Fenton cathode. The better separation of photo-generated carriers contribute more to the overall degradation enhancement than the photo-electrons generated H2O2 and the subsequent Fenton reaction on the cathode during the PEC/EF process. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Cadmium Sulfide and Nickel Synergetic Co-catalysts Supported on Graphitic Carbon Nitride for Visible-Light-Driven Photocatalytic Hydrogen Evolution

    OpenAIRE

    Xinzheng Yue; Shasha Yi; Runwei Wang; Zongtao Zhang; Shilun Qiu

    2016-01-01

    Design and preparation of noble-metal-free photocatalysts is of great importance for photocatalytic water splitting harvesting solar energy. Here, we report the high visible-light-driven hydrogen evolution upon the hybrid photocatalyst system consisting of CdS nanocrystals and Ni@NiO nanoparticles grown on the surface of g-C3N4. The hybrid system shows a high H2-production rate of 1258.7??mol h?1 g?1 in the presence of triethanolamine as a sacrificial electron donor under visible light irradi...

  3. Controllable assembly of well-defined monodisperse Au nanoparticles on hierarchical ZnO microspheres for enhanced visible-light-driven photocatalytic and antibacterial activity.

    Science.gov (United States)

    Wang, Yuan; Fang, Hua-Bin; Zheng, Yan-Zhen; Ye, Rongqin; Tao, Xia; Chen, Jian-Feng

    2015-12-07

    A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of the ZMS/Au composites as well as the reproducibility and controllability of the entire assembly process. Results on the photoelectrochemical performance characterized by EIS and transient photocurrent response spectra indicate that the ZMS/Au composites possess increased photoinduced charge separation and transfer efficiency compared to the pure ZMS film. As a result, the hybrid composites exhibited enhanced decomposition activity for methylene blue and salicylic acid as well as antibacterial activity in killing S. aureus and E. coli under visible light irradiation. It can be noted that well-distributed Au components even at a rather low Au/ZnO weight ratio of ∼1.2% also exhibited extraordinary photocatalysis. Such a facile and controllable self-assembly approach may be viable for preparing high-performance visible-light-driven ZMS/Au photocatalysts in a simple and controllable way, and consequently, the technology may extend to other plasmon-enhanced heterostructures made of nanostructured semiconductors and noble metals for great potential application in environmental protection.

  4. CTAB-Assisted Fabrication of Bi₂WO₆ Thin Nanoplates with High Adsorption and Enhanced Visible Light-Driven Photocatalytic Performance.

    Science.gov (United States)

    Zhou, Yuxue; Lv, Pengfei; Meng, Xiangdong; Tang, Yanping; Huang, Pingping; Chen, Xiaobing; Shen, Xiaoshuang; Zeng, Xianghua

    2017-05-22

    Two-dimensional thin Bi₂WO₆ nanoplates have been fabricated using a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. We investigated the proposed formation mechanism based on the crystalline structures of the thin Bi₂WO₆ nanoplates. The high adsorption ability and excellent visible-light driven photocatalytic activities of the Bi₂WO₆ nanoplates were illustrated, in view of exposed (001) facets of nanoplates possessing faster separation of photo-generated charge carriers and increased catalytically active sites. Such a cost-effective way to obtain Bi₂WO₆ nanoplates offers new possibilities for the design of adsorptive semiconductor photocatalysts with strengthened photocatalytic activities.

  5. One-Pot Synthesis of Cu2ZnSnSe4 Nanoplates and their Visible-Light-Driven Photocatalytic Activity

    Science.gov (United States)

    Han, Zhenzhen; Li, Nan; Shi, Aihua; Wang, Haohua; Ma, Feng; Lv, Yi; Wu, Rongqian

    2018-01-01

    A SeO2 ethanol solution as the facile precursor has been used for the preparation of quaternary Cu2ZnSnSe4 (CZTSe) nanoplates. Monodispersed single-phase CZTSe nanoplates have been prepared successfully by a facile one-pot thermal chemical method. The as-prepared CZTSe nanoplates show uniform morphology with a bandgap of 1.4 eV. As a proof of concept, the CZTSe nanoplates have been used as a visible-light-driven photocatalyst for Rhodamine B dye degradation and show high photocatalytic activity and stability. The excellent dye removal is mainly ascribed to the efficient light utilization of CZTSe nanoplates.

  6. Facile fabrication of Ag3VO4/attapulgite composites for highly efficient visible light-driven photodegradation towards organic dyes and tetracycline hydrochloride

    Science.gov (United States)

    Luo, Yuting; Luo, Jie; Duan, Guorong; Liu, Xiaoheng

    2017-12-01

    An efficient one-dimensional attapulgite (ATP)-based photocatalyst, Ag3VO4/ATP nanocomposite, was fabricated by a facile deposition precipitation method with well-dispersed Ag3VO4 nanoparticles anchored on the surface of natural ATP fibers. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectroscopy (UV-vis DRS) were employed to investigate the morphologies, structure, and optical property of the prepared photocatalysts. The photocatalytic experiments indicated that the Ag3VO4/ATP nanocomposites exhibited enhanced visible light-driven photocatalytic activity towards the degradation of rhodamine B (RhB), methyl orange (MO), and tetracycline hydrochloride (TCH), of which the 20 wt% Ag3VO4/ATP sample showed superb photocatalytic performance. As demonstrated by N2 adsorption-desorption, photocurrent measurements, electrochemical impedance spectroscopy (EIS), and photoluminescence (PL) spectra analyses, the improved photocatalytic activity arose from the enlarged surface area, the facilitated charge transfer, and the suppressed recombination of photogenerated charge carriers in Ag3VO4/ATP system. Furthermore, radical scavengers trapping experiments and recycling tests were also conducted. This work gives a new insight into fabrication of highly efficient, stable, and cost-effective visible light-driven photocatalyst for practical application in wastewater treatment and environmental remediation.

  7. Synthesis and visible-light-driven photocatalytic activity of p–n heterojunction Ag{sub 2}O/NaTaO{sub 3} nanocubes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Songbo [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Xu, Dongbo [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013 (China); Chen, Biyi; Luo, Bifu [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Yan, Xu [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013 (China); Xiao, Lisong, E-mail: xiaolisong123@sina.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Shi, Weidong, E-mail: swd1978@ujs.edu.cn [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2016-10-15

    Highlights: • We firstly report a facile way to prepare the visible-light-driven Ag{sub 2}O/NaTaO{sub 3}p–n heterojunction by chemical precipitation method. • The Ag{sub 2}O/NaTaO{sub 3} heterojunction shows the highest photocatalytic activity than the pure NaTaO{sub 3} and Ag{sub 2}O nanoparticles under visible light. • The enhancement of the heterojunction photocatalytic activity was discussed and the photocatalytic mechanism was tested in our paper. • In summary, we think that the Ag{sub 2}O/NaTaO{sub 3} heterojunction with the strong visible light absorption and efficient photocatalytic activity have been extended application in photocatalysis for organic dyes pollutants degradation and purification of water. - Abstract: The constructing of p–n heterojunction photocatalytic system has received much attention in environmental purification and hydrogen generation from water. In this study, an efficient visible-light-driven p–n heterojunction Ag{sub 2}O/NaTaO{sub 3} was successfully prepared by chemical precipitation method at room temperature. It showed an enhanced photocatalytic activity for the degradation of rhodamine B (RhB) under visible-light irradiation, much higher than those of either individual Ag{sub 2}O or NaTaO{sub 3}. The reactive species scavenger results indicated the superoxide anion radicals (·O{sup 2−}) played key roles in RhB decoloration. From the experimental results and the relative band gap position of these semiconductors, a detailed possible photocatalytic mechanism of the Ag{sub 2}O/NaTaO{sub 3} heterojunction under visible light was proposed. The enhancement of the photocatalytic activity was attributed to the interfacial electronic interaction between NaTaO{sub 3} and Ag{sub 2}O and the high migration efficiency of photogenerated carriers.

  8. Fabrication of porous tungsten oxide via anodizing in an ammonium nitrate/ethylene glycol/water mixture for visible light-driven photocatalyst

    Science.gov (United States)

    Kikuchi, Tatsuya; Kawashima, Jun; Natsui, Shungo; Suzuki, Ryosuke O.

    2017-11-01

    Fabrication of a nanoporous tungsten oxide film via anodizing of tungsten in an ammonium nitrate (NH4NO3)/ethylene glycol (EG)/water (H2O) mixture is reported for use as a visible light-driven photocatalyst. Anodizing of tungsten in a 1.0 M NH4NO3/EG solution containing less than 0.1 vol% H2O resulted in active dissolution of the tungsten substrate. As the H2O concentration increased to more than 25 vol%, a thin barrier oxide film was formed on the tungsten substrate. A thick porous tungsten oxide with numerous nanopores measuring several tens of nanometer in diameter was fabricated via anodizing at a moderate H2O concentration of 1.0 vol%. The porous oxide consisted of a double-layered structure with an outer porous layer and an inner dense layer, and the outer porous layer became thinner as the NH4NO3 concentration decreased. A uniform porous oxide film from the top surface to the bottom interface was fabricated via anodizing at 20 V in a 0.02 M NH4NO3/EG solution containing 1.0 vol% H2O at 313 K. The porous tungsten oxide exhibited visible light-driven photocatalytic activity for the photocatalytic decomposition of methylene blue.

  9. Template-free growth of well-crystalline α-Fe2O3 nanopeanuts with enhanced visible-light driven photocatalytic properties.

    Science.gov (United States)

    Zheng, Xin; Jiao, Yang; Chai, Fang; Qu, Fengyu; Umar, Ahmad; Wu, Xiang

    2015-11-01

    Well-crystalline homogeneous α-Fe2O3 nanopeanuts were synthesized, characterized and utilized as an effective photocatalysts for the photocatalytic degradation of toxic and harmful organic dyes, i.e. Congo red (CR), Eosin red (ER) and methylene blue (MB). The nanopeanuts were synthesized by facile one-step hydrothermal process without employing any templates and characterized in detail in terms of their morphological and structural properties. The detailed characterizations confirmed the well-crystallinity, large-scale growth and rhombohedral crystal structure of the synthesized nanopeanuts. Further, the detailed growth processes of prepared nanopeanuts were studied by examining the effects of reaction time, temperature and amounts of hexamethylenetetramine (HMT) on the shapes and sizes of the products. Thus, based on the observed experimental evidences, a possible growth mechanism for the formation of nanopeanuts was also proposed. Finally, the nanopeanuts were used as efficient visible-light driven photocatalyst for the photocatalytic degradation of organic dyes and the observed degradation rates were MB (57%)light irradiation. Interestingly, it was seen that the photocatalytic degradation of nanopeanuts was higher than other α-Fe2O3 nanostructures such as nanospindles and commercial α-Fe2O3 which revealed that the prepared α-Fe2O3 nanopeanuts are excellent visible-light driven photocatalyst for the photocatalytic degradation of harmful and toxic organic dyes. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Suitable Fundamental Properties of Ta0.75V0.25ON Material for Visible-Light-Driven Photocatalysis: A DFT Study

    KAUST Repository

    Harb, Moussab

    2016-11-29

    By applying calculations based on density functional theory, and on density functional perturbation theory, together with generalized gradient approximation-Perdew–Burke–Emzerho and screened Coulomb hybrid HSE06 functionals, we predict novel and suitable fundamental parameters of the stable monoclinic Ta0.75V0.25ON semiconductor for solar water splitting. In addition to its predicted bandgap of 2.0 eV in the required zone for solar-driven water splitting, this material reveals a high visible-light absorption coefficient, high static dielectric constant, high hole and electron mobilities along the [001] and [010] crystallographic directions, relatively low exciton binding energy, and suitable band edge energy levels for oxidizing water and reducing protons. The optical, charge-carrier transport, and redox features predicted for this material are found to be considerably better than those obtained for Ta3N5, which is the most common semiconductor photocatalyst used in visible-light-driven water splitting.

  11. Visible-light-driven oxidation of primary C-H bonds over CdS with dual co-catalysts graphene and TiO2.

    Science.gov (United States)

    Yang, Min-Quan; Zhang, Yanhui; Zhang, Nan; Tang, Zi-Rong; Xu, Yi-Jun

    2013-11-22

    Selective activation of primary C-H bonds for fine chemicals synthesis is of crucial importance for the sustainable exploitation of available feedstocks. Here, we report a viable strategy to synthesize ternary GR-CdS-TiO2 composites with an intimate spatial integration and sheet-like structure, which is afforded by assembling two co-catalysts, graphene and TiO2, into the semiconductor CdS matrix with specific morphology as a visible light harvester. The GR-CdS-TiO2 composites are able to serve as a highly selective visible-light-driven photocatalyst for oxidation of saturated primary C-H bonds using benign oxygen as oxidant under ambient conditions. This work demonstrates a wide, promising scope of adopting co-catalyst strategy to design more efficient semiconductor-based photocatalyst toward selective activation of C-H bonds using solar light and molecular oxygen.

  12. Preparation of TiO2/Ag binary nanocomposite as high-activity visible-light-driven photocatalyst via graft polymerization

    Science.gov (United States)

    Tae Park, Jung; Soo Lee, Chang; Hun Park, Cheol; Hak Kim, Jong

    2017-10-01

    We report the synthesis of a TiO2/Ag binary nanocomposite with high activity for visible-light-driven photocatalysts using graft copolymerization: (1) conversion of terminal OH groups on the surface of TiO2 nanoparticles to Cl groups, (2) graft polymerization from TiO2-Cl via ATRP with ionically charged poly(styrene sulfonic acid), (3) ion exchange process with an AgNO3 solution following sintering. TiO2/Ag binary nanocomposite showed enhanced photocatalytic performance for the degradation of methyl orange under visible light illumination. The improved photocatalytic performance of the TiO2/Ag binary nanocomposite was due to the plasmonic effect, recombination rate of electron-hole pairs that was suppressed by Ag nanoparticles.

  13. Unique and facile solvothermal synthesis of mesoporous WO3 using a solid precursor and a surfactant template as a photoanode for visible-light-driven water oxidation

    Science.gov (United States)

    2014-01-01

    Mesoporous tungsten trioxide (WO3) was prepared from tungstic acid (H2WO4) as a tungsten precursor with dodecylamine (DDA) as a template to guide porosity of the nanostructure by a solvothermal technique. The WO3 sample (denoted as WO3-DDA) prepared with DDA was moulded on an electrode to yield efficient performance for visible-light-driven photoelectrochemical (PEC) water oxidation. Powder X-ray diffraction (XRD) data of the WO3-DDA sample calcined at 400°C indicate a crystalline framework of the mesoporous structure with disordered arrangement of pores. N2 physisorption studies show a Brunauer-Emmett-Teller (BET) surface area up to 57 m2 g-1 together with type IV isotherms and uniform distribution of a nanoscale pore size in the mesopore region. Scanning electron microscopy (SEM) images exhibit well-connected tiny spherical WO3 particles with a diameter of ca. 5 to 20 nm composing the mesoporous network. The WO3-DDA electrode generated photoanodic current density of 1.1 mA cm-2 at 1.0 V versus Ag/AgCl under visible light irradiation, which is about three times higher than that of the untemplated WO3. O2 (1.49 μmol; Faraday efficiency, 65.2%) was evolved during the 1-h photoelectrolysis for the WO3-DDA electrode under the conditions employed. The mesoporous electrode turned out to work more efficiently for visible-light-driven water oxidation relative to the untemplated WO3 electrode. PMID:25313301

  14. MoS2 quantum dots@TiO2 nanotube composites with enhanced photoexcited charge separation and high-efficiency visible-light driven photocatalysis.

    Science.gov (United States)

    Zhao, Fenfen; Rong, Yuefei; Wan, Junmin; Hu, Zhiwen; Peng, Zhiqin; Wang, Bing

    2018-01-10

    MoS2 quantum dots (QDs) that are 5 nm in size were deposited on the surface of ultrathin TiO2 nanotubes (TNTs) with 5 nm wall thickness by using an improved hydrothermal method to form a MoS2 QDs@TNT visible-light photocatalyst. The ultrathin TNTs with high percentage of photocatalytic reactive facets were fabricated by the commercially available TiO2 nanoparticles (P25) through an improved hydrothermal method, and the MoS2 QDs were acquired by using a surfactant-assisted technique. The novel MoS2 QDs@TNT photocatalysts showed excellent photocatalytic activity with a decolorization rate of 92% or approximately 3.5 times more than that of pure TNTs for the high initial concentration of methylene blue solution (20 mg/L) within 40 min under visible-light irradiation. MoS2 as the co-catalysts favored the broadening of TNTs into the visible-light absorption scope. The quantum confinement and edge effects of the MoS2 QDs and the heterojunction formed between the MoS2 QDs and TNTs efficiently extended the lifetime of photoinduced charges, impeded the recombination of photoexcited electron-hole pairs, and improved the visible-light-driven high-efficiency photocatalysis. © 2018 IOP Publishing Ltd.

  15. Intensification of abamectin pesticide degradation using the combination of ultrasonic cavitation and visible-light driven photocatalytic process: Synergistic effect and optimization study.

    Science.gov (United States)

    Mosleh, Soleiman; Rahimi, Mahmood Reza

    2017-03-01

    Degradation of abamectin pesticide was carried out using visible light driven Cu2(OH)PO4-HKUST-1 MOF photocatalyst through the sonophotocatalytic technique. Cu2(OH)PO4-HKUST-1 MOF as a visible-light driven photocatalyst, was synthesized and characterized by XRD, SEM, EDS and DRS. The direct bang gaps of HKUST-1 MOF and Cu2(OH)PO4-HKUST-1 MOF were estimated about 2.63 and 2.59eV, respectively, which reveals that these photocatalysts can be activated under blue light illumination. All sonophotodegradation experiments were performed using a continuous flow-loop reactor. The central composite design (CCD) methodology was applied for modeling, optimization and investigation of influence of operational parameters, i.e. irradiation time, pH, solution flow rate, oxygen flow rate, initial concentration and photocatalyst dosage on the sonophotocatalytic degradation of abamectin. The maximum degradation efficiency of 99.93% was found at optimal values as 20min, 4, 90mL/min, 0.2mL/min, 30mg/L and 0.4g/L, for irradiation time, pH, solution flow rate, oxygen flow rate, initial concentration and photocatalyst dosage, respectively. Evaluation of the synergism in the combination of ultrasonic and photocatalysis lead to a synergistic index of 2.19, which reveals that coupling of ultrasonic and photocatalysis has a greater efficiency than the sum of individual procedures for degradation of abamectin. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Visible light driven mineralization of spiramycin over photostructured N-doped TiO2on up conversion phosphors.

    Science.gov (United States)

    Sacco, Olga; Vaiano, Vincenzo; Sannino, Diana; Ciambelli, Paolo

    2017-04-01

    A novel visible light-active photocatalyst formulation (NdT/OP) was obtained by supporting N-doped TiO 2 (NdT) particles on up-conversion luminescent organic phosphors (OP). The photocatalytic activity of such catalysts was evaluated for the mineralization process of spiramycin in aqueous solution. The effect of NdT loading in the range 15-60wt.% on bulk and surface characteristics of NdT/OP catalysts was investigated by several chemico-physical characterization techniques. The photocatalytic performance of NdT/OP catalysts in the removal of spyramicin from aqueous solution was assessed through photocatalytic tests under visible light irradiation. Total organic carbon (TOC) of aqueous solution, and CO and CO 2 gas concentrations evolved during the photodegradation were analyzed. A dramatic enhancement of photocatalytic activity of the photostructured visible active NdT/OP catalysts, compared to NdT catalyst, was observed. Only CO 2 was detected in gas-phase during visible light irradiation, proving that the photocatalytic process is effective in the mineralization of spiramycin, reaching very high values of TOC removal. The photocatalyst NdT/OP at 30wt.% of NdT loading showed the highest photocatalytic activity (58% of TOC removed after 180min irradiation against only 31% removal after 300min of irradiation of NdT). We attribute this enhanced activity to the high effectiveness in the utilization of visible light through improved light harvesting and exploiting. OP particles act as "photoactive support", able to be excited by the external visible light irradiation, and reissue luminescence of wavelength suitable to promote NdT photomineralization activity. Copyright © 2016. Published by Elsevier B.V.

  17. A visible-light-driven composite photocatalyst of TiO2 nanotube arrays and graphene quantum dots

    Directory of Open Access Journals (Sweden)

    Donald K. L. Chan

    2014-05-01

    Full Text Available TiO2 nanotube arrays are well-known efficient UV-driven photocatalysts. The incorporation of graphene quantum dots could extend the photo-response of the nanotubes to the visible-light range. Graphene quantum dot-sensitized TiO2 nanotube arrays were synthesized by covalently coupling these two materials. The product was characterized by Fourier-transform infrared spectrometry (FTIR, scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, thermogravimetric analysis (TGA and UV–vis absorption spectroscopy. The product exhibited high photocatalytic performance in the photodegradation of methylene blue and enhanced photocurrent under visible light irradiation.

  18. Hybrid copper doped titania/polythiophene nanorods as efficient visible light-driven photocatalyst for degradation of organic pollutants

    Directory of Open Access Journals (Sweden)

    M. Ravi Chandra

    2017-12-01

    Full Text Available The hybrid Cu–TiO2/polythiophene nanorods (HNRs were prepared by modified sol–gel technique at low temperature through oxidative polymerization of thiophene. The prepared HNRs and Cu–TiO2 nanorods without polymer (CTNRs were characterized by using XRD, TEM, IR, UV–vis DRS and XPS. IR, XPS and XRD confirm polythiophene (PTh covered Cu–TiO2 nanorod in hybrid with rutile phase without affecting the crystal form of TiO2. TEM analysis reveals the shape and morphology of CTNRs and HNRs. TEM images of HNRs show that the metal oxide has nanorods like shape with lengths and diameters of about 35–60 and 15–25 nm respectively. From UV–visible DRS spectra, HNRs exhibit a broad and strong absorption in visible range, indicating that the incorporation of PTh onto the surface of Cu–TiO2 nanorod in hybrid can extend the photo response range of TiO2. The photocatalytic activity of HNRs shows higher degradation when compared with CTNRs under visible light irradiation by degradation of Rhodamine B (RhB and Orange G (OG. There is no degradation of PTh was observed under visible light irradiation till five runs which is examined from photocatalytic activity, which indicates stability and reusability of photocatalyst.

  19. Hydrogenation temperature related inner structures and visible-light-driven photocatalysis of N–F co-doped TiO{sub 2} nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei, E-mail: wangweinj0603@126.com; Ni, Yaru, E-mail: niyr2000@hotmail.com; Lu, Chunhua, E-mail: lchnjut@163.com; Xu, Zhongzi, E-mail: xzznjut@163.com

    2014-01-30

    A systematic study has been devoted to prepare N–F co-doped anatase TiO{sub 2} nanosheets with further hydrogenation treatment at different temperatures. The hydrogenation temperature plays a significant role in changing the inner structure of TiO{sub 2} from N–F co-doping to the truly hydrogenated characteristic, resulting in various bandgap structures with different light absorption ability and photogenerated electron–hole pair separation efficiency. Moreover, the visible-light-driven photocatalytic activity not only depend on the light absorption ability, but also affected by the amount of defect states significantly. Results indicate that isolated defect state will serve as photogenerated electron–hole pair recombination center, while a large amount of combined defect states will truly reduce the bandgap, enhance the light absorption and the photogenerated electron–hole pair separation efficiency. The photocatalyst hydrogenated at 500 °C, which has a specific bandgap structure, gives the highest ability in the degradation of phenol under the visible light irradiation. This simple investigation is of great significance for the design and preparation of anion modified TiO{sub 2}-based photocatalysts with specific crystal structures to make sufficient use of the visible light for environment protection.

  20. Synthesis and visible-light-driven photocatalytic activity of p-n heterojunction Ag2O/NaTaO3 nanocubes

    Science.gov (United States)

    Yang, Songbo; Xu, Dongbo; Chen, Biyi; Luo, Bifu; Yan, Xu; Xiao, Lisong; Shi, Weidong

    2016-10-01

    The constructing of p-n heterojunction photocatalytic system has received much attention in environmental purification and hydrogen generation from water. In this study, an efficient visible-light-driven p-n heterojunction Ag2O/NaTaO3 was successfully prepared by chemical precipitation method at room temperature. It showed an enhanced photocatalytic activity for the degradation of rhodamine B (RhB) under visible-light irradiation, much higher than those of either individual Ag2O or NaTaO3. The reactive species scavenger results indicated the superoxide anion radicals (rad O2-) played key roles in RhB decoloration. From the experimental results and the relative band gap position of these semiconductors, a detailed possible photocatalytic mechanism of the Ag2O/NaTaO3 heterojunction under visible light was proposed. The enhancement of the photocatalytic activity was attributed to the interfacial electronic interaction between NaTaO3 and Ag2O and the high migration efficiency of photogenerated carriers.

  1. Cube-like Cu2MoS4 photocatalysts for visible light-driven degradation of methyl orange

    Directory of Open Access Journals (Sweden)

    Ke Zhang

    2015-07-01

    Full Text Available Cube-like Cu2MoS4 nanoparticles with low-index facets and high crystallinity were fabricated via a hydrothermal method. The as-obtained nanocubes with an average size of 40-60 nm are composed of stacking-Cu2MoS4 layers separated by a weak Van der Waals gap of 0.5 nm. A strong absorption at visible light region is observed in the nanocube aqueous solution, indicating its optical-band gap of 1.78 eV. The photocatalytic measurements reveal that the nanocubes can thoroughly induce the degradation of methyl orange under visible light irradiation with good structural stability. Our finding may provide a way in design and fabrication of transition metal dichalcogenide nanostructures for practical applications.

  2. Biochemical Synthesis of Ag/AgCl Nanoparticles for Visible-Light-Driven Photocatalytic Removal of Colored Dyes

    OpenAIRE

    Xiyun Zhao; Jie Zhang; Binsong Wang; Amir Zada; Muhammad Humayun

    2015-01-01

    Photocatalytic removal of organic pollution such as waste colored dyes was a promising technique for environment technique. However, effective photocatalysts were needed to enhance the photocatalytic efficiency. Ag/AgCl was regarded as high performance catalyst for photocatalytic degradation. Ag/AgCl nanoparticles were biochemically prepared with metabolin of living fungi which was used as reductant and characterized by X-Ray diffraction (XRD), UV-visible spectroscopy and transmission electro...

  3. Quick and Facile Preparation of Visible light-Driven TiO2 Photocatalyst with High Absorption and Photocatalytic Activity

    OpenAIRE

    Yucheng Yang; Ting Zhang; Ling Le; Xuefeng Ruan; Pengfei Fang; Chunxu Pan; Rui Xiong; Jing Shi; Jianhong Wei

    2014-01-01

    Self-doping TiO2 has recently attracted considerable attention for its high photocatalytic activity under visible-light irradiation. However, the literature reported synthetic methods until now were very time-consuming. In this study, we establish a quick and facile method for obtaining self-doping TiO2 with the use of directly treated commercial P25 at a desired temperature for only 5 min through spark plasma sintering technology. With the using of this method, the modified P25 samples exhib...

  4. Visible Light-Driven Photocatalytic Performance of N-Doped ZnO/g-C3N4 Nanocomposites.

    Science.gov (United States)

    Kong, Ji-Zhou; Zhai, Hai-Fa; Zhang, Wei; Wang, Shan-Shan; Zhao, Xi-Rui; Li, Min; Li, Hui; Li, Ai-Dong; Wu, Di

    2017-09-06

    N-doped ZnO/g-C3N4 composites have been successfully prepared via a facile and cost-effective sol-gel method. The nanocomposites were systematically characterized by XRD, FE-SEM, HRTEM, FT-IR, XPS, and UV-vis DRS. The results indicated that compared with the pure N-doped ZnO, the absorption edge of binary N-doped ZnO/g-C3N4 shifted to a lower energy with increasing the visible-light absorption and improving the charge separation efficiency, which would enhance its photocatalytic activity. Compared with the pure g-C3N4, ZnO, N-doped ZnO and the composite ZnO/g-C3N4, the as-prepared N-doped ZnO/g-C3N4 exhibits a greatly enhanced photocatalytic degradation of methylene blue and phenol under visible-light irradiation. Meanwhile, N-doped ZnO/g-C3N4 possesses a high stability. Finally, a proposed mechanism for N-doped ZnO/g-C3N4 is also discussed. The improved photocatalysis can be attributed to the synergistic effect between N-doped ZnO and g-C3N4, including the energy band structure and enhanced charge separation efficiency.

  5. Enhanced visible-light-driven photocatalytic bacteria disinfection by g-C3N4-AgBr.

    Science.gov (United States)

    Deng, Jun; Liang, Jialiang; Li, Mian; Tong, Meiping

    2017-04-01

    g-C3N4-AgBr was synthesized by depositing AgBr nanoparticles onto g-C3N4. Scanning electron microscopy (SEM), Transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Photoluminescence (PL) spectra were employed to characterize the as-synthesized photocatalysts. The disinfection activities towards representative Gram-negative strain E. coli and Gram-positive strain S. aureus were examined under visible light irradiation. Complete inactivation of 3×10(6)CFU/mL viable cell density was reached in 60min for E. coli and 150min for S. aureus, respectively. Ag(+) released from the photocatalysts did not contribute to the photocatalytic disinfection process. Direct contact of g-C3N4-AgBr composites and bacterial cells, as well as the presence of O2 was indispensable for the cell inactivation. Photo-generated holes, surface bounded OH, and indirect generation of intracellular active species played important roles in disinfection process of g-C3N4-AgBr under visible light irradiation. The disruption of outside structure of cells as well as inner cell injury led to the inactivation. High pH condition led to increasing the cell disinfection due to the generation of surface bounded OH. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Visible Light-Driven Photocatalytic Performance of N-Doped ZnO/g-C3N4 Nanocomposites

    Science.gov (United States)

    Kong, Ji-Zhou; Zhai, Hai-Fa; Zhang, Wei; Wang, Shan-Shan; Zhao, Xi-Rui; Li, Min; Li, Hui; Li, Ai-Dong; Wu, Di

    2017-09-01

    N-doped ZnO/g-C3N4 composites have been successfully prepared via a facile and cost-effective sol-gel method. The nanocomposites were systematically characterized by XRD, FE-SEM, HRTEM, FT-IR, XPS, and UV-vis DRS. The results indicated that compared with the pure N-doped ZnO, the absorption edge of binary N-doped ZnO/g-C3N4 shifted to a lower energy with increasing the visible-light absorption and improving the charge separation efficiency, which would enhance its photocatalytic activity. Compared with the pure g-C3N4, ZnO, N-doped ZnO and the composite ZnO/g-C3N4, the as-prepared N-doped ZnO/g-C3N4 exhibits a greatly enhanced photocatalytic degradation of methylene blue and phenol under visible-light irradiation. Meanwhile, N-doped ZnO/g-C3N4 possesses a high stability. Finally, a proposed mechanism for N-doped ZnO/g-C3N4 is also discussed. The improved photocatalysis can be attributed to the synergistic effect between N-doped ZnO and g-C3N4, including the energy band structure and enhanced charge separation efficiency.

  7. One-pot synthesis of visible-light-driven plasmonic photocatalyst Ag/AgCl in ionic liquid.

    Science.gov (United States)

    Xu, Hui; Li, Huaming; Xia, Jiexiang; Yin, Sheng; Luo, Zhijun; Liu, Ling; Xu, Li

    2011-01-01

    Plasmonic photocatalyst Ag/AgCl was prepared by in situ hydrothermal method with the contribution of 1-octyl-3-methylimidazolium chloride ([Omim]Cl), in which the [Omim]Cl ionic liquid acted not only as a precursor but also as a reducing reagent in the process of formation of Ag⁰. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric and differential scanning calorimetry (TG-DSC). The photocatalytic activity of the composites were evaluated by degradation of methyl orange (MO) under visible light irradiation. The experimental results showed that the high activity and stability of Ag/AgCl photocatalysts under visible-light irradiation were due to their localized surface plasmon resonance (LSPR). Based on the characterization of the structure and photocatalytic performance, the LSPR was determined by synergetic effect of many factors, such as particle size of metallic Ag, contents of the Ag⁰ nanoparticles, and the extent of metallic Ag dispersing. A photocatalytic mechanism of the Ag/AgCl photocatalyst was also proposed.

  8. Reduced graphene oxides loaded-ZnS/CuS heteronanostructures as high-activity visible-light-driven photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Bin [College of Materials Science and Engineering, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University, Changsha 410082 (China); College of Mechanical Engineering, Hunan University of Arts and Science, Changde 415000 (China); Chen, Xiaohua, E-mail: 240939138@qq.com [College of Materials Science and Engineering, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University, Changsha 410082 (China); Chen, Chuansheng; Ning, Xutao; Deng, Weina [College of Materials Science and Engineering, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University, Changsha 410082 (China)

    2014-01-05

    Highlights: • The nanocomposite of ZnS/CuS heterostructures decorated rGO is prepared. • Electrons in rGO have efficient oxygen reduction power. • Holes in the ZnS have high oxidation power. • The charge transfers between ZnS, CuS and rGO are proposed. -- Abstract: The reduced graphene oxides (rGO) loaded-ZnS/CuS heteronanostructures have been successfully prepared for the first time. Scanning electron microscopy and transmission electron microscopy observations confirm that ZnS/CuS heteronanostructures are decorated on the rGO. The experimental results reveal that these novel nanostructures exhibit a visible-light photocatalytic activities for methyl orange (MO) dye degradation. The high visible photocatalytic performances are attributed to photoinduced interfacial charge transfer in the heteronanostructures and their further separation and transfer by rGO. This new nanostructure is expected to show considerable potential applications in water purification as well as optoelectronic fields at a large scale.

  9. Biphasic TiO2 nanoparticles decorated graphene nanosheets for visible light driven photocatalytic degradation of organic dyes

    Science.gov (United States)

    Alamelu, K.; Raja, V.; Shiamala, L.; Jaffar Ali, B. M.

    2018-02-01

    We present characterization of biphasic TiO2 nanoparticles and its graphene nanocomposite synthesized by cost effective, hydrothermal method. The structural properties and morphology of the samples were characterized by series of spectroscopic and microscopic techniques. Introducing high surface area graphene could suppress the electron hole pair recombination rate in the nanocomposite. Further, the nanocomposite shows red-shift of the absorption edge and contract of the band gap from 2.98 eV to 2.85 eV. We have characterized its photocatalytic activity under natural sunlight and UV filtered sunlight irradiation. Data reveal graphene-TiO2 composite exhibit about 15 and 3.5 folds increase in degradability of Congo red and Methylene Blue dyes, respectively, comparison to pristine TiO2. This underscores the marginal effect of UV component of sunlight on the degradation ability of composite, implying its increased efficiency in harnessing visible region of solar spectrum. We have thus developed a visible light active graphene composite catalyst that can degrade both cationic and anionic dyes and making it potentially useful in environmental remediation and water splitting applications, under direct sunlight.

  10. Chromate enhanced visible light driven TiO{sub 2} photocatalytic mechanism on Acid Orange 7 photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yeoung-Sheng; Shen, Jyun-Hong [Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology (YunTech), Douliou, Yunlin, Taiwan (China); Horng, Jao-Jia, E-mail: horngjj@gmail.com [Department of Safety, Health and Environmental Engineering, National Yunlin University of Science and Technology (YunTech), Douliou, Yunlin, Taiwan (China)

    2014-06-01

    Highlights: • Photocatalysis of Cr(VI) and TiO{sub 2} were studied by ESR analysis on DMPO-OH signals. • Mechanism of Cr(VI)-enhanced by visible light was different from that by UV. • O{sub 2} adsorbed on TiO{sub 2} surfaces could react with Cr(VI) to lower photoenergy needed. • Even by UV, no TiO{sub 2} photocatalysis was observed without O{sub 2} solution. • Visible light and Cr(VI) redox reaction could activate TiO{sub 2} and would yield ·OH. - Abstract: When hexavalent chromium (Cr(VI)) is added to a TiO{sub 2} photocatalytic reaction, the decolorization and mineralization efficiencies of azo dyes Acid Orange 7 (AO7) are enhanced even though the mechanism is unclear. This study used 5,5-dimethyl-L-pyrroline-N-oxide (DMPO) as the scavenger and the analysis of Electron Spin Resonance (ESR) to investigate this enhancement effect by observing the hydroxyl radical (·OH) generation of the Cr(VI)/TiO{sub 2} system under UV and visible light (Vis) irradiation. With Cr(VI), the decolorization efficiencies were approximately 95% and 62% under UV and Vis, and those efficiencies were 25% less in the absence of Cr(VI). The phenomena of the DMPO-OH signals during the ESR analysis under Vis 405 and 550 nm irradiation were obviously the enhancement effects of Cr(VI) in aerobic conditions. In anoxic conditions, the catalytic effects of Cr(VI) could not be achieved due to the lack of a redox reaction between Cr(VI) and the adsorbed oxygen at the oxygen vacancy sites on the TiO{sub 2} surfaces{sub .} The results suggest that by introducing the agents of redox reactions such as chromate ions, we could lower the photoenergy of TiO{sub 2} needed and allow Vis irradiation to activate photocatalysis.

  11. Visible-Light-Driven Photoisomerization and Increased Rotation Speed of a Molecular Motor Acting as a Ligand in a Ruthenium(II) Complex.

    Science.gov (United States)

    Wezenberg, Sander J; Chen, Kuang-Yen; Feringa, Ben L

    2015-09-21

    Toward the development of visible-light-driven molecular rotary motors, an overcrowded alkene-based ligand and the corresponding ruthenium(II) complex is presented. In our design, a 4,5-diazafluorenyl coordination motif is directly integrated into the motor function. The photochemical and thermal isomerization behavior has been studied by UV/Vis and NMR spectroscopy. Upon coordination to a Ru(II) bipyridine complex, the photoisomerization process can be driven by visible (λmax = 450 nm) instead of UV light and furthermore, a large increase of the speed of rotation is noted. DFT calculations point to a contraction of the diazafluorenyl lower half upon metal-coordination resulting in reduced steric hindrance in the "fjord region" of the molecule. Consequently, it is shown that metal-ligand interactions can play an important role in the adjustment of both photophysical and thermodynamic properties of molecular motors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Systematic research on Ag2X (X = O, S, Se, Te) as visible and near-infrared light driven photocatalysts and effects of their electronic structures

    Science.gov (United States)

    Jiang, Wei; Wu, Zhaomei; Zhu, Yingming; Tian, Wen; Liang, Bin

    2018-01-01

    Four silver chalcogen compounds, Ag2O, Ag2S, Ag2Se and Ag2Te, can be utilized as visible-light-driven photocatalysts. In this research, the electronic structures of these compounds were analyzed by simulation and experiments to systematically reveal the relationship between photocatalytic performance and energetic structure. All four chalcogenides exhibited interesting photocatalytic activities under ultraviolet, visible and near-infrared light. However, their photocatalytic performances and stability significantly depended on the band gap width, and the valence band and conduct band position, which was determined by their composition. Increasing the X atomic number from O to Te resulted in the upward movement of the valence band top and the conduct band bottom, which resulted in narrower band gaps, a wider absorption spectrum, a weaker photo-oxidization capacity, a higher recombination probability of hole and electron pairs, lower quantum efficiency, and worse stability. Among them, Ag2O has the highest photocatalytic performance and stability due to its widest band gap and lowest position of VB and CB. The combined action of photogenerated holes and different radicals, depending on the different electronic structures, including anion ozone radical, hydroxide radical, and superoxide radical, was observed and understood. The results of experimental observations and simulations of the four silver chalcogen compounds suggested that a proper electronic structure is necessary to obtain a balance between photocatalytic performance and absorbable light region in the development of new photocatalysts.

  13. Fabrication of Ce/N co-doped TiO{sub 2}/diatomite granule catalyst and its improved visible-light-driven photoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yan; Liu, Kuiren, E-mail: liukr@smm.neu.edu.cn

    2017-02-15

    Highlights: • Ce/N co-doped TiO{sub 2}/diatomite granule (CNTD-G) was prepared via sol-gel method. • The optimal doping amount of Ce was determined. • The effects of impurity ions on photodegradation process were studied. • The intermediates generated during photodegradation process were deduced. • The mechanism of photodegradation process was proposed. - Abstract: Eliminating antibiotic remnants in aquatic environment has become one of the hottest topics among current research works. Thus, we prepared Ce, N co-doped TiO{sub 2}/diatomite granule (CNTD-G) catalyst to provide a new method. As one typical antibiotics, oxytetracycline (OTC) was selected as the target pollutant to be degradated under visible light irradiation. The carrier diatomite helped the spread of TiO{sub 2} nanoparticles onto its surface, and inhibited their agglomeration. The synergy of Ce and N dopants highly improved the visible-light-driven photoactivity of TiO{sub 2}. The optimal doping amount and degradation conditions were determined. Besides, the effects of impurity ions were also investigated, including cations: Ca{sup 2+}, Mg{sup 2+}; or anions: NO{sub 3}{sup −}, SO{sub 4}{sup 2−} and PO{sub 4}{sup 3−}. The intermediates generated during degradation process were studied, and the mechanism of the photodegradation process was proposed. CNTD-G could be easily collected from the reactor, and showed excellent recyclability.

  14. Visible-light-driven Ag/AgBr/ZnFe2O4composites with excellent photocatalytic activity for E. coli disinfection and organic pollutant degradation.

    Science.gov (United States)

    Xu, Yuanguo; Liu, Qingqing; Liu, Chenchen; Zhai, Yunpeng; Xie, Meng; Huang, Liying; Xu, Hui; Li, Huaming; Jing, Junjie

    2018-02-15

    Visible-light-driven (VLD) Ag/AgBr/ZnFe 2 O 4 composites with different weight ratios of ZnFe 2 O 4 were synthesized via a facile hydrothermal method. The ZnFe 2 O 4 was evenly dispersed on the surface of Ag/AgBr particles with the diameter about 20 nm. The obtained Ag/AgBr/ZnFe 2 O 4 composites exhibited the high bacterial disinfection efficiency and inactivated bacteria after 120 min visible illumination, which was better than those of with pure ZnFe 2 O 4 and Ag/AgBr. Due to the introduction of ZnFe 2 O 4 , the Ag/AgBr/ZnFe 2 O 4 inactivated bacterial cells through the generation of H 2 O 2 , which generated from the electron reduction on the conduction band of ZnFe 2 O 4 in the system. The photocatalytic experiments indicated that as-prepared samples showed the good photocatalytic performance toward degradation of methyl orange (MO) dye. In a word, the Ag/AgBr/ZnFe 2 O 4 composites, as the antibacterial photocatalyst, is a promising candidate material in wastewater decontamination. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Layer structured Na2Ni(MoO4)2 particles as a visible-light-driven photocatalyst for degradation of methylene blue

    Science.gov (United States)

    Lu, Yuting; Chen, Luyang; Huang, Yanlin; Chen, Cuili; Kim, Sun Il; Seo, Hyo Jin

    2015-03-01

    A new visible-light-driven photocatalyst of Na2Ni(MoO4)2 particle was prepared by the modified Pechini method. The crystal structure was measured by X-ray diffraction (XRD) and the structural refinement. The sample was investigated by scanning electron microscope (SEM), transmission electron microscopy (TEM), and UV-vis absorption spectrum measurements. The average size of Na2Ni(MoO4)2 particle is about 180 nm. Na2Ni(MoO4)2 particle have an efficient optical absorption in the UV-visible light wavelength region with a direct allowed electronic transition of 2.06 eV. The effective photodegradation of methylene blue (MB) dye was demonstrated, which benefits from the special crystal structure of Na2Ni(MoO4)2 particle. This crystal lattice has two infinite chains formed by (Ni,Na)O6 and MoO4 polyhedra standing in lines alone with the inner wall of the hexagonal tunnels. This results in the efficient optical absorption and provides more chances for electron-hole separations, which can further react with dye molecules to oxidize the dye pollutant into non-toxic products.

  16. Visible-light-driven Photocatalytic N-arylation of Imidazole Derivatives and Arylboronic Acids on Cu/graphene catalyst.

    Science.gov (United States)

    Cui, Yan-Li; Guo, Xiao-Ning; Wang, Ying-Yong; Guo, Xiang-Yun

    2015-07-20

    N-aryl imidazoles play an important role as structural and functional units in many natural products and biologically active compounds. Herein, we report a photocatalytic route for the C-N cross-coupling reactions over a Cu/graphene catalyst, which can effectively catalyze N-arylation of imidazole and phenylboronic acid, and achieve a turnover frequency of 25.4 h(-1) at 25°C and the irradiation of visible light. The enhanced catalytic activity of the Cu/graphene under the light irradiation results from the localized surface plasmon resonance of copper nanoparticles. The Cu/graphene photocatalyst has a general applicability for photocatalytic C-N, C-O and C-S cross-coupling of arylboronic acids with imidazoles, phenols and thiophenols. This study provides a green photocatalytic route for the production of N-aryl imidazoles.

  17. Sandwiched ZnO@Au@CdS nanorod arrays with enhanced visible-light-driven photocatalytical performance

    Science.gov (United States)

    Ren, Shoutian; Wang, Yingying; Fan, Guanghua; Gao, Renxi; Liu, Wenjun

    2017-11-01

    The development of high-performance photocatalysts is central to efforts focused on taking advantage of solar energy to overcome environmental and energy crises. Integrating different functional materials artfully into nanostructures can deliver more efficient photocatalytic activity. Here, sandwiched ZnO@Au@CdS nanorod films were synthesized via successive ZnO nanorod electrodeposition, Au sputtering and CdS electrodeposition. The as-synthesized composites were characterized by UV–vis spectrophotometer, x-ray diffractometer, scanning and transmission electron microscopy. Their photocatalytic activity was assessed by degrading Rhodamine B solution under visible light irradiation. ZnO@Au@CdS exhibited better photocatalytic performance than ZnO@CdS throughout the visible light region, and the corresponding enhancement factor of Au nanoparticles was measured as a function of CdS loading amount, and it could reach 190% with CdS deposition for 1 min. The normalized rate constant could reach 0.387 h‑1 for ZnO@Au@CdS-1min, which was equivalent to or better than results in reference photocatalysts. The enhancement mechanism of Au nanoparticles was estimated by comparing the monochromatic photocatalytic action spectra with the absorption spectrum of ZnO@Au@CdS, and it was mainly determined by incident photon energy. With selective excitation of Au nanoparticles by incident photons, the excited hot electrons in Au NPs are transferred to the conduction band of ZnO to boost photocatalytic reaction. With selective excitation of CdS, the enhanced interband absorption of CdS and relay station effect of Au nanoparticles should be responsible for the enhanced photocatalytic performance. Our work not only opens the door to the design of efficient supported photocatalysts, but also helps to understand the enhancement mechanism of LSPR effect on the photoelectric conversion of semiconductors.

  18. In situ DRIFT and kinetic studies of photocatalytic degradation on benzene vapor with visible-light-driven silver vanadates

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lung-Chuan [Department of Polymer Materials, Kun Shan University, Yung Kang City, Tainan, Taiwan (China); Pan, Guan-Ting; Yang, Thomas C.-K. [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan (China); Chung, Tsair-Wang [Department of Chemical Engineering, Chung Yuan Christian University, Taoyuan, Taiwan (China); Huang, Chao-Ming, E-mail: charming@mail.ksu.edu.tw [Department of Environmental Engineering, Kun Shan University, Yung Kang City, Tainan, Taiwan (China)

    2010-06-15

    The visible-light active silver vanadates with different types of crystallines (Ag{sub 4}V{sub 2}O{sub 7} and Ag{sub 3}VO{sub 4} phases) were synthesized by an environmentally friendly aqueous process. The parameters of hydrothermal temperature and hydrothermal time were tuned to maximize the photocatalytic efficiency for the decomposition of benzene vapor under visible-light irradiation. The quantum efficiencies of the photocatalysts are compared on the basis of the crystalline phases, surface area, intensity of surface hydroxyl groups, and Broensted acid sites. From the results of DRIFTS studies, the photocatalytic activities strongly depend on the intensities of the Broensted acidity and hydroxyl groups presented on the silver vanadates. The sample synthesized at 140 deg. C and 4 h (HM140) exhibits the best photocatalytic activity; it has a reaction rate constant (k{sub app}) of 1.42 min{sup -1}, much higher than that of P25 (k{sub app} = 0.13 min{sup -1}). For an irradiation time of 720 min, the mineralization yields of benzene were 48% and 11% for HM140 and P25, respectively. Based on the short-term decrease of benzene concentration and the long-term increase of CO{sub 2} concentration, the photocatalytic ability of the HM140 sample is significantly superior to that of P25. The highest activity can be attributed to the synergetic effects of the richest Broensted acid sites, and a favorable crystalline phase combined with abundant surface hydroxyl groups.

  19. Black TiO2 nanobelts/g-C3N4 nanosheets Laminated Heterojunctions with Efficient Visible-Light-Driven Photocatalytic Performance

    Science.gov (United States)

    Shen, Liyan; Xing, Zipeng; Zou, Jinlong; Li, Zhenzi; Wu, Xiaoyan; Zhang, Yuchi; Zhu, Qi; Yang, Shilin; Zhou, Wei

    2017-01-01

    Black TiO2 nanobelts/g-C3N4 nanosheets laminated heterojunctions (b-TiO2/g-C3N4) as visible-light-driven photocatalysts are fabricated through a simple hydrothermal-calcination process and an in-situ solid-state chemical reduction approach, followed by the mild thermal treatment (350 °C) in argon atmosphere. The prepared samples are evidently investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption, and UV-visible diffuse reflectance spectroscopy, respectively. The results show that special laminated heterojunctions are formed between black TiO2 nanobelts and g-C3N4 nanosheets, which favor the separation of photogenerated electron-hole pairs. Furthermore, the presence of Ti3+ and g-C3N4 greatly enhance the absorption of visible light. The resultant b-TiO2/g-C3N4 materials exhibit higher photocatalytic activity than that of g-C3N4, TiO2, b-TiO2 and TiO2/g-C3N4 for degradation of methyl orange (95%) and hydrogen evolution (555.8 μmol h−1 g−1) under visible light irradiation. The apparent reaction rate constant (k) of b-TiO2/g-C3N4 is ~9 times higher than that of pristine TiO2. Therefore, the high-efficient laminated heterojunction composites will have potential applications in fields of environment and energy. PMID:28165021

  20. Black TiO2 nanobelts/g-C3N4 nanosheets Laminated Heterojunctions with Efficient Visible-Light-Driven Photocatalytic Performance

    Science.gov (United States)

    Shen, Liyan; Xing, Zipeng; Zou, Jinlong; Li, Zhenzi; Wu, Xiaoyan; Zhang, Yuchi; Zhu, Qi; Yang, Shilin; Zhou, Wei

    2017-02-01

    Black TiO2 nanobelts/g-C3N4 nanosheets laminated heterojunctions (b-TiO2/g-C3N4) as visible-light-driven photocatalysts are fabricated through a simple hydrothermal-calcination process and an in-situ solid-state chemical reduction approach, followed by the mild thermal treatment (350 °C) in argon atmosphere. The prepared samples are evidently investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption, and UV-visible diffuse reflectance spectroscopy, respectively. The results show that special laminated heterojunctions are formed between black TiO2 nanobelts and g-C3N4 nanosheets, which favor the separation of photogenerated electron-hole pairs. Furthermore, the presence of Ti3+ and g-C3N4 greatly enhance the absorption of visible light. The resultant b-TiO2/g-C3N4 materials exhibit higher photocatalytic activity than that of g-C3N4, TiO2, b-TiO2 and TiO2/g-C3N4 for degradation of methyl orange (95%) and hydrogen evolution (555.8 μmol h-1 g-1) under visible light irradiation. The apparent reaction rate constant (k) of b-TiO2/g-C3N4 is ~9 times higher than that of pristine TiO2. Therefore, the high-efficient laminated heterojunction composites will have potential applications in fields of environment and energy.

  1. MoS{sub 2}/reduced graphene oxide hybrid with CdS nanoparticles as a visible light-driven photocatalyst for the reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Wen-chao, E-mail: wenchao.peng@tju.edu.cn [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong (China); Chen, Ying [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Li, Xiao-yan, E-mail: xlia@hkucc.hku.hk [Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong (China)

    2016-05-15

    Highlights: • MoS{sub 2}/rGO hybrid is synthesized using a one-step hydrothermal method. • MoS{sub 2}/rGO hybrid is used as the support and cocatalyst for CdS nanoparticles. • CdS-MoS{sub 2}/rGO composite is effective photocatalyst for 4-NP reduction in visible light. • Ammonium formate is an effective sacrificial agent for 4-NP photocatalytic reduction. - Abstract: Photocatalytic reduction of nitroaromatic compounds to aromatic amines using visible light is an attractive process that utilizes sunlight as the energy source for the chemical conversions. Herewith we synthesized a composite material consisting of CdS nanoparticles grown on the surface of MoS{sub 2}/reduced graphene oxide (rGO) hybrid as a novel photocatalyst for the reduction of 4-nitrophenol (4-NP). The CdS-MoS{sub 2}/rGO composite is shown as a high-performance visible light-driven photocatalyst. Even without a noble-metal cocatalyst, the catalyst exhibited a great activity under visible light irradiation for the reduction of 4-NP to much less toxic 4-aminophenol (4-AP) with ammonium formate as the sacrificial agent. Composite CdS-0.03(MoS{sub 2}/0.01rGO) was found to be the most effective photocatalyst for 4-NP reduction. The high photocatalytic performance is apparently resulted from the synergetic functions of MoS{sub 2} and graphene in the composite, i.e. the cocatalysts serve as both the active adsorption sites for 4-NP and electron collectors for the separation of electron-hole pairs generated by CdS nanoparticles. The laboratory results show that the CdS-MoS{sub 2}/rGO composite is a low-cost and stable photocatalyst for effective reduction and detoxification of nitroaromatic compounds using solar energy.

  2. Development of high efficient visible light-driven N, S-codoped TiO2 nanowires photocatalysts

    Science.gov (United States)

    Zhang, Yanlin; Liu, Peihong; Wu, Honghai

    2015-02-01

    One-dimensional (1D) nanowire material (especially nonmetal doped 1D nanowires) synthesized by a facile way is of great significance and greatly desired as it has higher charge carrier mobility and lower carrier recombination rate. N, S-codoped TiO2 nanowires were synthesized using titanium sulfate as a precursor and isopropanol as a protective capping agent by a hydrothermal route. The obtained doped nanowires were characterized by XRD, SEM, HRTEM, SAED, XPS, BET and UV-vis absorption spectrum. The incorporation of N and S into TiO2 NWs can lead to the expansion of its lattice and remarkably lower its electron-transfer resistance. Photocatalytic activity measurement showed that the N, S-codoped TiO2 nanowires with high quantum efficiency revealed the best photocatalytic performance for atrazine degradation under visible light irradiation compared to N, S-codoped TiO2 nanoparticles and S-doped TiO2 nanowires, which was attributed to (i) the synergistic effect of N and S doping in narrowing the band gap, separating electron-hole pairs and increasing the photoinduced electrons, and (ii) extending the anatase-to-rutile transformation temperature above 600 °C.

  3. Facile Low-Temperature Synthesis of Carbon Nanotube/ Nanohybrids with Enhanced Visible-Light-Driven Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Yunlong Xie

    2012-01-01

    Full Text Available We demonstrate a facile and novel chemical precipitation strategy for the accurate coating of TiO2 nanoparticles on the surface of carbon nanotubes (CNTs to form CNT/TiO2 nanohybrids, which only requires titanium sulfate and CNTs as starting materials and reacts in the alkaline solution at 60°C for 6 h. Using this process, the as-prepared hybrid structures preserved the good dispersity and uniformity of initial CNTs. Furthermore, the CNT/TiO2 nanohybrids show a broad blue luminescence at 469 nm and exhibit significantly enhanced photocatalytic activity for the degradation of rhodamine B (RhB under visible-light irradiation, which is about 1.5 times greater than that of commercial Degussa P25 TiO2 nanoparticles. It is believed that this facile chemical precipitation strategy is scalable and its application can be extended to synthesize other CNT/oxide nanohybrids for various applications.

  4. Ag2O/sodium alginate-reduced graphene oxide aerogel beads for efficient visible light driven photocatalysis

    Science.gov (United States)

    Ma, Yuhua; Wang, Jiajia; Xu, Shimei; Feng, Shun; Wang, Jide

    2018-02-01

    In this work, one facile and green method was developed to resolve the instinct defects of pure Ag2O and increase visible-light photocatalytic activity of Ag2O-based catalyst. In which, Ag2O was immobilized in sodium alginate-reduced graphene oxide (ALG-rGO) aerogel beads. The as-prepared aerogel beads showed a well-defined interconnected three-dimensional porous network and displayed the highest photocatalytic activity with a mass ratio of 40:1 (ALG:rGO). For the degradation of cationic Rhodamine B (RhB) and anionic dye Orange II (OII) dyes, rate constants were 1.95 × 10-2 min-1 and 4.13 × 10-2 min-1, which were 2.4 and 3.1 times higher than those of Ag2O/ALG aerogel beads, respectively. The further studies demonstrated that presence of rGO can effectively decrease the size of Ag2O, extend photoresponding range (UV to near-infrared light spectrum), speed-up separate photogenerated electrons and holes, retard charge recombination, and prolong electron lifetime and effective carrier diffusion length. The potential mechanism for RhB and OII degrading was expounded, and main active species in the degradation reactions of dyes were investigated by a series of trapping experiments. It offered a promising photocatalyst to purify the wastewater, and provided a sophisticated understanding of the pivotal role rGO acting in photocatalysis.

  5. A computational study on the photoelectric properties of various Bi2O3 polymorphs as visible-light driven photocatalysts.

    Science.gov (United States)

    Wang, Fang; Cao, Kun; Zhang, Qian; Gong, Xuedong; Zhou, Ying

    2014-11-01

    This paper presents first-principle studies on the photoelectric properties of various Bi2O3 polymorphs. The intrinsic reason of different photocatalytic activities was revealed by electronic structures and optical features. Results showed that for α, β, and γ-Bi2O3, the top of valence bands were mainly constructed by Bi6s and O2p orbitals, and the bottom of conduction bands were dominantly composed by Bi6p orbital. However, two intermediate bands were found at the Fermi level for γ-Bi2O3, which leads to a two-step transition from the top of valence band to the bottom of conduction band and facilitates electron transition under irradiation. Absent forbidden gap was found in δ-Bi2O3, resulting in a semimetallic character due to its intrinsic oxygen vacancy and high ionic conductivity. Moreover, the optical properties of α, β, and γ-Bi2O3 were investigated by absorption spectrum, dielectric constant function, and energy loss spectroscopy. We concluded that the photocatalytic activities followed in the order of γ-Bi2O3 > β-Bi2O3 > α-Bi2O3, in accord with the experimental report. Calculation results illustrated the experimental observations and provided a useful guidance in exploring promising visible-light semiconductor photocatalysts.

  6. A facile chemical conversion synthesis of Sb2S3 nanotubes and the visible light-driven photocatalytic activities

    Science.gov (United States)

    2012-01-01

    We report a simple chemical conversion and cation exchange technique to realize the synthesis of Sb2S3 nanotubes at a low temperature of 90°C. The successful chemical conversion from ZnS nanotubes to Sb2S3 ones benefits from the large difference in solubility between ZnS and Sb2S3. The as-grown Sb2S3 nanotubes have been transformed from a weak crystallization to a polycrystalline structure via successive annealing. In addition to the detailed structural, morphological, and optical investigation of the yielded Sb2S3 nanotubes before and after annealing, we have shown high photocatalytic activities of Sb2S3 nanotubes for methyl orange degradation under visible light irradiation. This approach offers an effective control of the composition and structure of Sb2S3 nanomaterials, facilitates the production at a relatively low reaction temperature without the need of organics, templates, or crystal seeds, and can be extended to the synthesis of hollow structures with various compositions and shapes for unique properties. PMID:22448960

  7. Visible light driven photocatalytic degradation of rhodamine B using Mg doped cobalt ferrite spinel nanoparticles synthesized by microwave combustion method

    Science.gov (United States)

    Sundararajan, M.; John Kennedy, L.; Nithya, P.; Judith Vijaya, J.; Bououdina, M.

    2017-09-01

    Co1-xMgxFe2O4 (0≤x≤0.5) spinel nanoparticles were synthesized by a simple microwave combustion method. The characterization of the samples were performed using X-ray diffraction (XRD) analysis, scanning electron (SEM) microscopy, energy dispersive X-ray (EDX) analysis, UV-visible and diffuse reflectance (DRS) spectroscopy, photoluminescence (PL) spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry (VSM) analysis. The XRD patterns indicate the formation of cubic inverse spinel structure. The calculated average crystallite size using Debye Scherrer's equation is found to be around 46-38 nm. The morphology of spinel nanoparticles was observed from SEM images and the elemental mapping of magnesium doped cobalt ferrite was obtained by using energy dispersive X-ray technique. Optical studies were carried out for the deeper understanding of the conduction band (CB) and valence band (VB) edges of the synthesized nanoparticles. The intrinsic stretching vibrations of Fe3+-O2- in tetrahedral sites leads to the appearance of IR band at around 573 cm-1. The magnetic properties such as remanence magnetization (Mr), coercivity (Hc) and saturation magnetization (Ms) were calculated from the hysteresis curves. The maximum photocatalytic degradation efficiency for Co0.6Mg0.4Fe2O4 is around (99.5%) when compared to that of CoFe2O4 whose efficiency is around (73.0%). The improvement in photocatalytic degradation efficiency is due to the effective separation and prevention of electron-hole pair recombination. The R2 values for the first order rate kinetics are found to be better than R2 values for the second order rate kinetics and this proves that photocatalytic degradation of RhB dye follows first order kinetics. The probable mechanism for the photocatalytic degradation of RhB dye is proposed.

  8. Surface interaction between cubic phase NaNbO3 nanoflowers and Ru nanoparticles for enhancing visible-light driven photosensitized photocatalysis

    Science.gov (United States)

    Chen, Wei; Hu, Yin; Ba, Mingwei

    2018-03-01

    Ru nanoparticles supported on perovskite NaNbO3 with cubic crystal structure and nanoflower-like morphology was prepared by a convenient solvothermal method combined with photo-deposition technique. Crystal structure, chemical component and surface valence states determined by XRD, XPS, TEM and SEM demonstrated the metastable cubic phase of perovskite NaNbO3, and its modified surface by Ru species. Optical and electrochemical analysis, such as UV-vis DRS, OTCS and EIS, indicated the excellent photoelectrochemical properties and the efficient electron transfer of the composites. Compared with naked and Ru-doped NaNbO3, the composite photocatalyst exhibited outstanding performance for the degradation of RhB under visible light irradiation due to the dye self-photosensitization and the surface interaction between Ru metal nanoparticles and semiconductor. In-situ reduction of surface Ru oxide species in the photocatalytic process assisted the further improvement of the photocatalytic activity and stability. Investigation of the main active species during the photocatalysis confirmed the efficient transfer of the photo-generated electrons and the positive effect of oxygen defects in NaNbO3. Finally, possible mechanism of the present visible-light driven photocatalysis was proposed in detail. This work provided an alternative strategy to enhance the visible-light photocatalytic efficiency of the catalyst with wide band gap on the basis of the synergistic effect of dye self-photosensitization, interaction between NaNbO3 and its surface Ru nanoparticles, and the "self-doping" of oxygen defects in NaNbO3.

  9. Heterogeneous Single-Atom Catalyst for Visible-Light-Driven High-Turnover CO2Reduction: The Role of Electron Transfer.

    Science.gov (United States)

    Gao, Chao; Chen, Shuangming; Wang, Ying; Wang, Jiawen; Zheng, Xusheng; Zhu, Junfa; Song, Li; Zhang, Wenkai; Xiong, Yujie

    2018-02-14

    Visible-light-driven conversion of CO 2 into chemical fuels is an intriguing approach to address the energy and environmental challenges. In principle, light harvesting and catalytic reactions can be both optimized by combining the merits of homogeneous and heterogeneous photocatalysts; however, the efficiency of charge transfer between light absorbers and catalytic sites is often too low to limit the overall photocatalytic performance. In this communication, it is reported that the single-atom Co sites coordinated on the partially oxidized graphene nanosheets can serve as a highly active and durable heterogeneous catalyst for CO 2 conversion, wherein the graphene bridges homogeneous light absorbers with single-atom catalytic sites for the efficient transfer of photoexcited electrons. As a result, the turnover number for CO production reaches a high value of 678 with an unprecedented turnover frequency of 3.77 min -1 , superior to those obtained with the state-of-the-art heterogeneous photocatalysts. This work provides fresh insights into the design of catalytic sites toward photocatalytic CO 2 conversion from the angle of single-atom catalysis and highlights the role of charge kinetics in bridging the gap between heterogeneous and homogeneous photocatalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. 0D/2D Heterojunctions of Vanadate Quantum Dots/Graphitic Carbon Nitride Nanosheets for Enhanced Visible-Light-Driven Photocatalysis.

    Science.gov (United States)

    Ye, Meng-Yang; Zhao, Zhi-Hao; Hu, Zhuo-Feng; Liu, Le-Quan; Ji, Hui-Ming; Shen, Zhu-Rui; Ma, Tian-Yi

    2017-07-10

    0D/2D heterojunctions, especially quantum dots (QDs)/nanosheets (NSs) have attracted significant attention for use of photoexcited electrons/holes due to their high charge mobility. Herein, unprecedent heterojunctions of vanadate (AgVO 3 , BiVO 4 , InVO 4 and CuV 2 O 6 ) QDs/graphitic carbon nitride (g-C 3 N 4 ) NSs exhibiting multiple unique advances beyond traditional 0D/2D composites have been developed. The photoactive contribution, up-conversion absorption, and nitrogen coordinating sites of g-C 3 N 4 NSs, highly dispersed vanadate nanocrystals, as well as the strong coupling and band alignment between them lead to superior visible-light-driven photoelectrochemical (PEC) and photocatalytic performance, competing with the best reported photocatalysts. This work is expected to provide a new concept to construct multifunctional 0D/2D nanocomposites for a large variety of opto-electronic applications, not limited in photocatalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Molten salt-mediated formation of g-C3N4-MoS2 for visible-light-driven photocatalytic hydrogen evolution

    Science.gov (United States)

    Li, Ni; Zhou, Jing; Sheng, Ziqiong; Xiao, Wei

    2018-02-01

    Construction of two-dimensional/two-dimensional (2D/2D) hybrid with well-defined composition and microstructure is a general protocol to achieve high-performance catalysts. We herein report preparation of g-C3N4-MoS2 hybrid by pyrolysis of affordable melamine and (NH4)2MoS4 in molten LiCl-NaCl-KCl at 550 °C. Molten salts are confirmed as ideal reaction media for formation of homogeneous hybrid. Characterizations suggest a strong interaction between g-C3N4 and MoS2 in the hybrid, which results in an enhanced visible-light-driven photocatalytic hydrogen generation of the hybrid with an optimal g-C3N4/MoS2 ratio. The present study highlights the merits of molten salt methods on preparation of 2D photocatalysts and provides a rational design of 2D/2D hybrid catalysts for advanced environmental and energy applications.

  12. Solvent-Induced Deposition of Cu-Ga-In-S Nanocrystals onto a Titanium Dioxide Surface for Visible-Light-Driven Photocatalytic Hydrogen Production

    KAUST Repository

    Kandiel, Tarek

    2015-11-25

    In this paper, copper-gallium-indium-sulfide (CGIS) nanocrystals with different Ga/In ratios, i.e., CuGaxIn5-xS8, where x = 0, 1, 2, 3, 4 and 5, were synthesized and investigated for visible-light-driven hydrogen (H2) evolution from aqueous solutions that contain sulfide/sulfite ions. The synthesized CGIS nanocrystals were characterized by diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). With 1.0 wt.% Ru as a co-catalyst, the H2 evolution rate on CuGa2In3S8 (CGIS hereafter) showed the highest activity. The CGIS nanocrystals were deposited onto a TiO2 surface via a unique solvent-induced deposition method. The CGIS/TiO2 photocatalyst showed comparable activity to that obtained using bare CGIS nanocrystals when the photocatalyst amount was sufficient in the photoreactor system, suggesting that TiO2 remains intact in terms of photocatalytic activity. The quantity of CGIS nanocrystals, however, required to achieve the rate-plateau condition at saturation was much lower in the presence of TiO2. The enhanced activities at low CGIS loadings observed in the presence of TiO2 were explained by the improved dispersion of the powder suspension and optical path in the photoreactor. This TiO2 supported photocatalyst lowers the required amount of photocatalyst, which is beneficial from an economic point of view.

  13. Fabrication and high visible-light-driven photocurrent response of g-C3N4 film: The role of thiourea

    Science.gov (United States)

    Ye, Lijuan; Chen, Shijian

    2016-12-01

    We report on a convenient CVD fabrication of the uniform, compact and reproducible g-C3N4 solid films on indium-tin oxide substrates. It is found that mixing quantitative thiourea into melamine as co-precursor prompts the deposition of greenish-yellow, transparent and smooth g-C3N4 thin films. The thiourea apparently affects the crystalline, the surface morphologies and the energy band structures of g-C3N4 films by modulating the polymerization process of the precursors, and simultaneously introduces S dopants into the g-C3N4 films. Due to these roles of thiourea, the obtained S-doped g-C3N4 films as a photoelectrode show a high and stable visible-light-driven photocurrent response. To further improve the photocurrent, the construction of three heterojunction structure types based on g-C3N4 films is proposed and the corresponding charge transfer mechanisms are well discussed. The successful fabrication of high quality g-C3N4 films in this work provides a footstone to construct the heterojunction film structures based on the carbon nitrides for the photoelectrochemical overall water splitting.

  14. Cu2ZnSnS4@TiO2 p-n heterostructured nanosheet arrays: Controllable hydrothermal synthesis and enhanced visible light-driven photocatalytic activity

    Science.gov (United States)

    Gan, Tian; Li, Yan; Wang, Xiang-Zhuo; Wang, Xiao-Tian; Wang, Cheng-Wei

    2017-06-01

    We have designed and fabricated a novel particle/sheet p-n heterostructural nanosheet arrays of Cu2ZnSnS4@TiO2 via a facile two-step hydrothermal method. The results from characterizations of SEM, TEM, XRD, Raman spectra, XPS, and UV-vis spectrophotometer indicate that p-type Cu2ZnSnS4 (CZTS) nanoparticles were successfully assembled on the vertically oriented TiO2 nanosheet arrays, forming three-dimensional distributed p-n heterostructural film photocatalyst, which could efficiently expand spectral response, promote photoinduced charges separation, and increase the specific surface areas for photocatalytic reaction, and then strengthen samples' visible light-driven photocatalytic activity. Furthermore, we found that the absorption edges of the samples exhibited the red shift from 390 nm to 700 nm with the CZTS deposition time. The results of photocatalytic degradation methyl orange (MO) showed that the new type CZTS@TiO2 p-n heterostructural nanosheet arrays with 24 h hydrothermal reaction revealed the optimal degradation rate of K = 1.2 h-1, about 6.6 times higher than that of the pure TiO2 nanosheet arrays under the same conditions; and also demonstrated an excellent stability and reusability during the cyclic experiments, which would be primarily attributed to optimal loading capacities of CZTS nanoparticles and an adequate built-in electric field at their interfaces of p-n heterostructures.

  15. Preparation and characterization of visible-light-driven N-F-Ta tri-doped TiO{sub 2} photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei, E-mail: wwnjut@hotmail.com [State Key Laboratory of Materials-Orient Chemical Engineering, College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China); Lu, Chunhua, E-mail: lchnjut@163.com [State Key Laboratory of Materials-Orient Chemical Engineering, College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China); Ni, Yaru; Su, Mingxing; Huang, Wenjuan; Xu, Zhongzi [State Key Laboratory of Materials-Orient Chemical Engineering, College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer N-F-Ta tri-doping can further improve the visible-light photoactivity of N single doped TiO{sub 2}. Black-Right-Pointing-Pointer There are N 2p-Ta 5d hybridized states which narrow the band gap and reduce the photogenerated electrons and holes recombination rate located in the gap region of TiO{sub 2}. Black-Right-Pointing-Pointer The introduced F atoms enhance the N incorporation which further promote the N 2p-Ta 5d hybridized states. Black-Right-Pointing-Pointer Charge compensation during the doping process is a very important factor. - Abstract: A new strategy to synthesize visible-light-driven N doped and N-F-Ta tri-doped TiO{sub 2} nanocatalysts via a hydrothermal combined with heat treatment method applied in Rhodamine B (RhB) and phenol decomposition was reported. The tri-doped sample gave the highest visible-light photocatalytic activity when the molar ratio of Ta to Ti was 1%. At a low tri-doping level, physicochemical analysis indicated that the synergistic effects of N, F and Ta could effectively increase not only the crystallite surface area but also the light absorption and {center_dot}OH generation ability, which contributed to the enhancement of visible-light photocatalytic activities. EPR and XPS analysis demonstrated that N-Ta interaction induced the charge compensation to form N 2p-Ta 5d hybridized states which improved the separation ability of the photoexcited electron-hole pairs. Still, F incorporation facilitated the incorporation of N which further promoted the N 2p-Ta 5d hybridized states. The N 2p, {pi}*N-O, oxygen vacancy, Ti{sup 3+} and Ta 5d states were also responsible for the band gap narrowing. However, a high tri-doping level would affect the crystal growth and introduce too many defects into the lattice, reducing the visible-light photoactivity.

  16. A novel visible light-driven Ag3PO4/SBA-15 nanocomposite: Preparation and application in the photo-degradation of pollutants

    Science.gov (United States)

    Chai, Yuanyuan; Wang, Li; Ren, Jia; Dai, Wei-Lin

    2015-01-01

    A novel visible light-driven environmental-benign Ag3PO4/SBA-15 nanocomposite photo-catalyst was synthesized for the photo-degradation of pollutants. The exploration on adsorption and photo-catalysis of dye or organic pollution for the nanocomposite was carried out. The adsorption capability for Ag3PO4/SBA-15 nanocomposite increases by 3 times compared with that of the Ag3PO4 particles. The photo-catalytic activity of nanocomposite is higher than pristine Ag3PO4 nanoparticle for the degradation of RhB or MO under visible light irradiation (λ > 420 nm). The effect of Ag3PO4 loading on the catalytic performance was also studied. The results show that the optimum degradation is achieved over 20% Ag3PO4/SBA-15. Compared to pure Ag3PO4 nanoparticle, the most efficient catalyst showed 8 times higher photo-catalytic activity for the degradation of RhB. The Ag3PO4/SBA-15 catalysts were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and N2-adsorption-desorption isotherms (BET). A possible mechanism scheme regarding photo-degradation enhancement induced by dye enrichments has been proposed on the Ag3PO4/SBA-15 nanocomposite. Additionally, the SBA-15 support can enhance the efficiency of separation of catalyst from the reaction mixture, implying that the Ag3PO4 loading on the SBA-15 catalyst will not result in the extra environment and health problems and reduce the cost of wastewater treatment.

  17. Controllable synthesis of Bi2MoO6 nanosheets and their facet-dependent visible-light-driven photocatalytic activity

    Science.gov (United States)

    Yang, Zixin; Shen, Min; Dai, Ke; Zhang, Xuehao; Chen, Hao

    2018-02-01

    Bi2MoO6 nanosheets with exposed {010} facets were selectively synthesized through hydrothermal method by adjusting the pH value in the presence of cetyltrimethyl ammonium bromide (CTAB) as the templates. The effects of CTAB content and hydrothermal conditions on the morphologies and crystal phases of the products were determined by using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FTIR), Raman spectrometry, and Brunauer-Emmett-Teller surface area analyses. It is found that Bi2MoO6 nanosheets with relatively large particle sizes (plate length 0.5-3 μm) and special anisotropic growth along the {010} plane can be obtained from an alkaline hydrothermal environment. The band gap of Bi2MoO6 can be fine-tuned from 2.30 to 2.57 eV by adjusting the pH value of hydrothermal solution. The pH value has a significant effect on the composition of hydrothermal precursors, which results in Bi2MoO6 nanosheets with different ratio of {010} faces, especially the formation of Bi2O3 in the primary stage of the hydrothermal treatment is a key factor for the exposure of {010} facets. The visible-light-driven photocatalytic activities of the Bi2MoO6 products with different ratio of {010} facets exposed are investigated through the degradation of Rhodamine B, oxytetracycline, and tetracycline. Bi2MoO6 nanosheets synthesized at pH 10.0 with highest {010} facet exposed ratio exhibited highly efficient visible light photocatalytic activity for pollutant decomposition, which can be mainly attributed to the flake structures, the crystallinity and most importantly, the exposed {010} facet which generate high concentration of rad O2-.

  18. A visible-light-driven heterojuncted composite WO3/Bi12O17Cl2: Synthesis, characterization, and improved photocatalytic performance.

    Science.gov (United States)

    Zheng, Jiaojiao; Chang, Fei; Jiao, Mingzhi; Xu, Quan; Deng, Baoqing; Hu, Xuefeng

    2018-01-15

    Novel visible-light-driven WO 3 /Bi 12 O 17 Cl 2 heterojuncted photocatalysts with different mass ratios were successfully fabricated by a facile hydrothermal process and were characterized by XRD, UV-Vis DRS, SEM, TEM, HRTEM, XPS, BET, Raman, PL, and ESR techniques. The original morphology of Bi 12 O 17 Cl 2 was maintained after the addition of WO 3 nanoparticles and the specific surface area values of WBx composites were obviously enlarged. The intimate contact of both components in HRTEM confirmed the generation of smooth phase interface. These as-prepared samples were subjected to the photocatalytic degradation of dye rhodamine B (RhB) and tetracycline hydrochloride (TC) under visible light irradiation (λ≥420nm). Under identical conditions, WBx composites showed greatly enhanced photocatalytic performance in comparison to bare WO 3 and Bi 12 O 17 Cl 2 . Especially, the sample WB0.5 exhibited the highest photocatalytic removal outcome over RhB among all tested candidates and owned an apparent rate constant about 73.7, 7.1, 15.8 times of those pure WO 3 , Bi 12 O 17 Cl 2 , and N-doped TiO 2 , respectively. The enhancement of photocatalytic capability of composites mainly attributed to the suitable morphology, enlarged specific surface areas, strengthened optical property, and favorable well-aligned straddling band-structures. Active species entrapping experiments confirmed holes and superoxide radicals as major oxidative species, by which, a possible photocatalytic mechanism was primarily proposed. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Fabrication of a novel visible-light-driven photocatalyst Ag-AgI-TiO{sub 2} nanoparticles supported on carbon nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Dandan; Bai, Jie, E-mail: baijie@imut.edu.cn; Liang, Haiou; Wang, Junzhong; Li, Chunping

    2015-09-15

    Graphical abstract: - Highlights: • Visible-light-induced Ag-AgI-TiO{sub 2}/CNFs nanocomposites had been successfully prepared. • Ag-AgI-TiO{sub 2}/CNFs could be easily separated and recycled from an aqueous solution. • The application of CNFs acting as supporters made the photocatalysts have high adsorption capacity. • Ag-AgI-TiO{sub 2}/CNFs could efficiently degrade different organic dyes. - Abstract: Novel visible-light-driven photocatalysts Ag-AgI-TiO{sub 2} nanoparticles embedded onto carbon nanofibers were successfully prepared. Electrospinning technology followed by high-temperature calcination was adopted for the fabrication of carbon nanofibers (CNFs) acting as a supporter. Ag-TiO{sub 2}/CNFs nanocomposites were prepared by combining in situ reduction with physical adsorption process. Ag-AgI-TiO{sub 2}/CNFs were synthesized by oxidizing some silver nanoparticles (Ag NPs) contained in Ag-TiO{sub 2}/CNFs to silver iodine (AgI) via chemical oxidation method using iodine (I{sub 2}) as oxidation agents. The as-prepared nanocomposites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS), and Fourier transform infrared spectroscopy (FTIR). The as-fabricated Ag-AgI-TiO{sub 2}/CNFs showed high efficient adsorption and photocatalytic activity for decomposition of methyl orange (MO), acid red 18 (AR18), methylene blue (MB), and fluorescence sodium under visible light irradiation, which were attributed to the synergistic effects between the high adsorption capacity, good conductivity of carbon nanofibers, and the extraordinary plasma effect of Ag-AgI nanoparticles. In addition, the as-prepared composites could be easily separated from the solution phase due to the large length–diameter ratio of CNFs. The mechanism for the enhanced photocatalytic activity concerned with Ag-AgI-TiO{sub 2}/CNFs was proposed.

  20. Hydrothermal synthesis of CdS nanorods anchored on α-Fe2O3nanotube arrays with enhanced visible-light-driven photocatalytic properties.

    Science.gov (United States)

    Lei, Rui; Ni, Hongwei; Chen, Rongsheng; Gu, Huazhi; Zhang, Bowei; Zhan, Weiting

    2018-03-15

    be a promising and competitive visible-light-driven photocatalyst in the field of environment remediation. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Fabrication and high visible-light-driven photocurrent response of g-C{sub 3}N{sub 4} film: The role of thiourea

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Lijuan; Chen, Shijian, E-mail: sjchen@cqu.edu.cn

    2016-12-15

    Highlights: • Thiourea promotes the growth and crystalline of the g-C{sub 3}N{sub 4} films on ITO. • Thiourea introduces S dopants into the g-C{sub 3}N{sub 4} films. • The obtained S-doped g-C{sub 3}N{sub 4} thin films show high VLD photocurrent response. • Three heterojunction structure types based on the g-C{sub 3}N{sub 4} films are proposed. - Abstract: We report on a convenient CVD fabrication of the uniform, compact and reproducible g-C{sub 3}N{sub 4} solid films on indium-tin oxide substrates. It is found that mixing quantitative thiourea into melamine as co-precursor prompts the deposition of greenish-yellow, transparent and smooth g-C{sub 3}N{sub 4} thin films. The thiourea apparently affects the crystalline, the surface morphologies and the energy band structures of g-C{sub 3}N{sub 4} films by modulating the polymerization process of the precursors, and simultaneously introduces S dopants into the g-C{sub 3}N{sub 4} films. Due to these roles of thiourea, the obtained S-doped g-C{sub 3}N{sub 4} films as a photoelectrode show a high and stable visible-light-driven photocurrent response. To further improve the photocurrent, the construction of three heterojunction structure types based on g-C{sub 3}N{sub 4} films is proposed and the corresponding charge transfer mechanisms are well discussed. The successful fabrication of high quality g-C{sub 3}N{sub 4} films in this work provides a footstone to construct the heterojunction film structures based on the carbon nitrides for the photoelectrochemical overall water splitting.

  2. Synthesis of Reduced Grapheme Oxide as A Platform for loading β-NaYF4:Ho3+@TiO2Based on An Advanced Visible Light-Driven Photocatalyst.

    Science.gov (United States)

    Fan, Zihong; Wu, Tianhui; Xu, Xuan

    2017-10-23

    In this paper a novel visible light-driven ternary compound photocatalyst (β-NaYF 4 :Ho 3+ @TiO 2 -rGO) was synthesized using a three-step approach. This photocatalyst was characterized using X-ray diffraction, Raman scattering spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Transmission electron microscopy, X-ray photoelectron spectroscopy, fluorescence spectrometries, ultraviolet-visible diffuse reflectance spectroscopy, Brunauer-Emmett-Teller surface area measurement, electron spin resonance, three-dimensional fluorescence spectroscopy, and photoelectrochemical properties. Such proposed photocatalyst can absorb 450 nm visible light while emit 290 nm ultraviolet light, so as to realize the visible light-driven photocatalysis of TiO 2 . In addition, as this tenary compound photocatalyst enjoys effecitve capacity of charge separation, superior durability, and sound adsorb ability of RhB, it can lead to the red shift of wavelength of absorbed light. This novel tenary photocatalyst can reach decomposition rate of RhB as high as 92% after 10 h of irradiation by visible-light Xe lamp. Compared with the blank experiment, the efficiency was significantly improved. Recycle experiments showed that theβ-NaYF 4 :Ho 3+ @TiO 2 -rGOcomposites still presented significant photocatalytic activity after four successive cycles. Finally, we investigated visible-light-responsive photocatalytic mechanism of the β-NaYF 4 :Ho 3+ @TiO 2 -rGO composites. It is of great significance to design an effective solar light-driven photocatalysis in promoting environmental protection.

  3. Photocatalytical water decomposition on visible light-driven solid-solution compounds K{sub 4}Ce{sub 2}Ta{sub 10-x}Nb{sub x}O{sub 30} (x = 0-10)

    Energy Technology Data Exchange (ETDEWEB)

    Tian Mengkui, E-mail: tianmk@hotmail.com [School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, Guizhou (China); Shangguan Wenfeng, E-mail: shanguan@sjtu.edu.cn [Centre for Combustion and Environmental Protection, Shanghai Jiao Tong University, Shanghai 200030 (China)

    2012-01-05

    Highlights: Black-Right-Pointing-Pointer Visible light driven solid-solution compounds K{sub 4}Ce{sub 2}Ta{sub 10-x}Nb{sub x}O{sub 30} (x = 0-10) were synthesized by solid state reaction. Black-Right-Pointing-Pointer These solid-solution compounds demonstrated water decomposition activities under visible light irradiation. Black-Right-Pointing-Pointer Their electronic structures were studied based on the first principle calculation. Black-Right-Pointing-Pointer The proposed band structure has good agreement with their absorption properties and photocatalytic activities. - Abstract: A series of single phase solid-solution K{sub 4}Ce{sub 2}Ta{sub 10-x}Nb{sub x}O{sub 30} (x = 0-10) photocatalysts were synthesized by conventional high temperature solid state reaction. Their UV-vis diffuse reflectance spectra showed their absorbance edges shifted to long wavelength zone consistently with the increase of the amount of Nb for substituting Ta in these compounds, and the onsets of absorbance edges ranging from about 540 nm to 690 nm, corresponding to bandgap energy of 1.8-2.3 eV. These series of photocatalysts possess appropriate band gap (ca. 1.8-2.3 eV) and chemical level to use solar energy to decompose water into H{sub 2}, and the photocatalytical activities under visible light ({lambda} > 420 nm) demonstrated that the activities decreased correspondingly with the increase of the amount of Nb in these compounds, which is regarded as the result of the differences of their band structures. Furthermore, the photocatalytical activities and the photophysical properties of these visible light-driven photocatalysts K{sub 4}Ce{sub 2}Ta{sub 10-x}Nb{sub x}O{sub 30} (x = 0-10) were bridged by the first principle calculation based on Density Functional Theory with General Gradient Approximation and Plane-wave Pseudopotential methods.

  4. Visible-light-driven photoelectrochemical and photocatalytic performances of Cr-doped SrTiO3/TiO2 heterostructured nanotube arrays

    OpenAIRE

    Zhengbo Jiao; Tao Chen; Jinyan Xiong; Teng Wang; Gongxuan Lu; Jinhua Ye; Yingpu Bi

    2013-01-01

    Well-aligned TiO2 nanotube arrays have become of increasing significance because of their unique highly ordered array structure, high specific surface area, unidirectional charge transfer and transportation features. However, their poor visible light utilization as well as the high recombination rate of photoexcited electron-hole pairs greatly limited their practical applications. Herein, we demonstrate the fabrication of visible-light-responsive heterostructured Cr-doped SrTiO3/TiO2 nanotube...

  5. Quantum-confined bandgap narrowing of TiO2 nanoparticles by graphene quantum dots for visible-light-driven applications.

    Science.gov (United States)

    Wang, Shujun; Cole, Ivan S; Li, Qin

    2016-07-28

    We for the first time report a quantum-confined bandgap narrowing mechanism through which the absorption of two UV absorbers, namely the graphene quantum dots (GQDs) and TiO2 nanoparticles, can be easily extended into the visible light range in a controllable manner. Such a mechanism may be of great importance for light harvesting, photocatalysis and optoelectronics.

  6. Visible Light-Driven H 2 Production over Highly Dispersed Ruthenia on Rutile TiO 2 Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen-Phan, Thuy-Duong; Luo, Si; Vovchok, Dimitriy; Llorca, Jordi; Graciani, Jesús; Sanz, Javier Fernández; Sallis, Shawn; Xu, Wenqian; Bai, Jianming; Piper, Louis F. J.; Polyansky, Dmitry E.; Fujita, Etsuko; Senanayake, Sanjaya D.; Stacchiola, Dario J.; Rodriguez, José A.

    2016-01-04

    The immobilization of miniscule quantities of RuO2 (~0.1%) onto one-dimensional (1D) TiO2 nanorods (NRs) allows H2 evolution from water under visible light irradiation. Rod-like rutile TiO2 structures, exposing preferentially (110) surfaces, are shown to be critical for the deposition of RuO2 to enable photocatalytic activity in the visible region. The superior performance is rationalized on the basis of fundamental experimental studies and theoretical calculations, demonstrating that RuO2(110) grown as 1D nanowires on rutile TiO2(110), which occurs only at extremely low loads of RuO2, leads to the formation of a heterointerface that efficiently adsorbs visible light. The surface defects, band gap narrowing, visible photoresponse, and favorable upward band bending at the heterointerface drastically facilitate the transfer and separation of photogenerated charge carriers

  7. Visible Light-Driven Photocatalytic Performance of N-Doped ZnO/g-C^sub 3^N^sub 4^ Nanocomposites

    National Research Council Canada - National Science Library

    Ji-Zhou Kong; Hai-Fa Zhai; Wei Zhang; Shan-Shan Wang; Xi-Rui Zhao; Min Li; Hui Li; Ai-Dong Li; Di Wu

    2017-01-01

    .... The results indicated that compared with the pure N-doped ZnO, the absorption edge of binary N-doped ZnO/g-C3N4 shifted to a lower energy with increasing the visible-light absorption and improving...

  8. Ag3PO4/graphene-oxide composite with remarkably enhanced visible-light-driven photocatalytic activity toward dyes in water.

    Science.gov (United States)

    Chen, Guodong; Sun, Meng; Wei, Qin; Zhang, Yongfang; Zhu, Baocun; Du, Bin

    2013-01-15

    Ag(3)PO(4)/graphene-oxide (Ag(3)PO(4)/GO) composite has been synthesized by a liquid phase deposition method, and used for the photodegradation of organic dyes in water under visible light. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscope, N(2) sorption-desorption, and UV-vis diffuse reflectance spectra. The SEM image indicated that Ag(3)PO(4) particles were mainly distributed on the surface of GO sheets uniformly. DRS analysis revealed that the samples had good visible light response. The photocatalytic activity of Ag(3)PO(4)/GO composite was evaluated by decomposing of dyes (such as methyl orange, rhodamine B) in water under visible or UV-vis light irradiation. The degradation results indicated that the photocatalytic performance of Ag(3)PO(4)/GO was greatly enhanced due to the improved adsorption performance and separation efficiency of photo-generated carriers. The Ag(3)PO(4)/GO composite with GO content of 15 wt.% exhibited superior activity under visible light irradiation. After 50 min of reaction, the degradation ratio of MO was about 86.7%, while RhB solution could be completely degraded within 30 min of reaction. Further study proved that the direct oxidation of pollutants by holes has played a major role in the degradation process. The results of this work would provide a new sight for the construction of visible light-responsive photocatalysts with high performance. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Photodeposition-assisted synthesis of novel nanoparticulate In, S-codoped TiO2 powders with high visible light-driven photocatalytic activity

    Science.gov (United States)

    Hamadanian, M.; Reisi-Vanani, A.; Razi, P.; Hoseinifard, S.; Jabbari, V.

    2013-11-01

    In order to search for an efficient photocatalysts working under visible light illumination, we have investigated the effect of metal and nonmetal ions (In, S) codoping on the photocatalytic activity of TiO2 nanoparticles (TiO2 NPs) prepared by combining of sol-gel (SG) and photodeposition (PD) methods using titanium tetra isopropoxide (TTIP), indium nitrate (In(NO3)3) and thiourea as precursors. In this regard, at first three different percentage of S (0.05, 0.2 and 0.5) doped into the TiO2 by SG method, and then different amount of In(III) loaded on the surface of the prepared samples by PD technique. The results showed that the In, S-codoped TiO2 (In, S-TiO2) with a spheroidal shape demonstrates a smaller grain size than the pure TiO2. Meanwhile, the UV-vis DRS of In, S-TiO2 showed a considerable red shift to the visible region. Finally, the photocatalytic activity of In, S-TiO2 photocatalysts were evaluated by photooxidative degradation of methyl orange (MO) solution under UV and visible light illumination. As a result, it was found that 0.05%S-0.5%In/TiO2, 0.2%S-1.5%In/TiO2 and 0.5%S-0.5%In/TiO2 had the highest catalytic activity under visible light in each group and among these samples 0.2%S-1.5%In/TiO2 showed the best photocatalytic performance under visible light and decomposes more than 95% MO in only 90 min.

  10. One-pot synthesis of copper-doped graphitic carbon nitride nanosheet by heating Cu–melamine supramolecular network and its enhanced visible-light-driven photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Junkuo, E-mail: jkgao@zstu.edu.cn [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Wang, Jiangpeng [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Qian, Xuefeng; Dong, Yingying [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Xu, Hui; Song, Ruijing [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Yan, Chenfeng [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Zhu, Hangcheng [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Zhong, Qiwei [The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology (Zhejiang), College of Materials and Textiles, Zhejiang Sci-Tech University, Hangzhou 310018 (China); and others

    2015-08-15

    Here we report a novel synthetic pathway for preparation of Cu-doped g-C{sub 3}N{sub 4} (Cu-g-C{sub 3}N{sub 4}) with nanosheet morphology by using a two dimensional Cu–melamine supramolecular network as both sacrificial template and precursor. The specific surface area of Cu-g-C{sub 3}N{sub 4} is 40.86 m{sup 2} g{sup −1}, which is more than 7 times larger than that of pure g-C{sub 3}N{sub 4}. Cu-g-C{sub 3}N{sub 4} showed strong optical absorption in the visible-light region and expanded the absorption to the near-infrared region. The uniform nanosheet morphology, higher surface area and strong visible-light absorption have enabled Cu-g-C{sub 3}N{sub 4} exhibiting enhanced visible light photocatalytic activity for the photo-degradation of methylene blue (MB). The results indicate that metal–melamine supramolecular network can be promising precursors for the one step preparation of efficient metal-doped g-C{sub 3}N{sub 4} photocatalysts. - Graphical abstract: Cu-doped g-C{sub 3}N{sub 4} (Cu-g-C{sub 3}N{sub 4}) with nanosheet morphology was fabricated via a simple one step preparation by using a two dimensional Cu–melamine supra-molecular network as both sacrificial template and precursor. - Highlights: • Cu-doped g-C{sub 3}N{sub 4} (Cu-g-C{sub 3}N{sub 4}) with nanosheet morphology was prepared. • Cu-g-C{sub 3}N{sub 4} showed strong optical absorption in the visible-light region. • Cu-g-C{sub 3}N{sub 4} exhibits enhanced visible light photocatalytic activity.

  11. Hybridization of Cd0.2Zn0.8S with g-C3N4 nanosheets: a visible-light-driven photocatalyst for H2 evolution from water and degradation of organic pollutants.

    Science.gov (United States)

    Liu, Hong; Jin, Zhitong; Xu, Zhengzheng

    2015-08-28

    Novel visible-light-driven Cd0.2Zn0.8S/g-C3N4 inorganic-organic composite photocatalysts were synthesized by a facile hydrothermal method. The prepared Cd0.2Zn0.8S/g-C3N4 composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) experiments. Under visible-light irradiation, Cd0.2Zn0.8S/g-C3N4 photocatalysts displayed a higher photocatalytic activity than pure g-C3N4 and Cd0.2Zn0.8S for hydrogen evolution and degradation of pollutants, and the optimal g-C3N4 content was 20 wt%. The optimal composite showed a hydrogen evolution rate of 208.0 μmol h(-1). The enhancement of the photocatalytic activity should be attributed to the well-matched band structure and intimate contact interfaces between Cd0.2Zn0.8S and g-C3N4, which lead to the effective transfer and separation of the photogenerated charge carriers. Furthermore, the Cd0.2Zn0.8S/g-C3N4 photocatalysts showed excellent stability during photocatalytic hydrogen evolution and degradation of pollutants.

  12. CeVO4 nanofibers hybridized with g-C3N4 nanosheets with enhanced visible-light-driven photocatalytic activity

    Science.gov (United States)

    Li, Li; Wang, Haoran; Wang, Xiong

    2018-01-01

    The g-C3N4/CeVO4 composites were successfully synthesized by hybridizing CeVO4 nanofibers with g-C3N4 nanosheets. The photocatalytic activity of g-C3N4/CeVO4 composites was evaluated for the photodegradation of methylene blue under visible light irradiation. Among them, the 50 wt% g-C3N4/CeVO4 composites presented the highest photocatalytic activity, about 2 and 3.2 times higher than those of CeVO4 and g-C3N4, respectively. The improved catalytic activity was owed to the hybridization, which facilitated the rapid separation of photoinduced carriers and enhanced the visible light harvesting. A possible photocatalytic mechanism was proposed.

  13. Enhanced visible-light-driven photocatalytic activity of mesoporous TiO(2-x)N(x) derived from the ethylenediamine-based complex.

    Science.gov (United States)

    Jiang, Zheng; Kong, Liang; Alenazey, Feraih Sh; Qian, Yangdong; France, Liam; Xiao, Tiancun; Edwards, Peter P

    2013-06-21

    A facile solvent evaporation induced self-assembly (SEISA) strategy was developed to synthesize mesoporous N-doped anatase TiO2 (SE-meso-TON) using a single organic complex precursor derived in situ from titanium butoxide and ethylenediamine in ethanol solution. After the evaporation of ethanol in a fume hood and subsequent calcinations at 450 °C, the obtained N-doped TiO2 (meso-TON) anatase was of finite crystallite size, developed porosity, large surface area (101 m(2) g(-1)) and extended light absorption in the visible region. This SE-meso-TON also showed superior photocatalytic activity to the SG-meso-TON anatase prepared via sol-gel synthesis. On the basis of characterization results from XRD, XPS, N2 adsorption-desorption and ESR, the enhanced visible-light-responsive photocatalytic activity of SE-meso-TON was assigned to its developed mesoporosity and reduced oxygen vacancies.

  14. Porous TiO{sub 2} nanofibers decorated CdS nanoparticles by SILAR method for enhanced visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Fengyu; Hou, Dongfang, E-mail: dfhouok@126.com; Hu, Fuchao; Xie, Kui; Qiao, Xiuqing; Li, Dongsheng, E-mail: lidongsheng1@126.com

    2017-01-01

    Graphical abstract: A heterojunction photocatalyst with CdS Nanoparticles self-assembled via SILAR Method at surfaces of electrospun TiO2 nanofibers shows enhanced visible-light photocatalytic activities. - Highlights: • Combined electrospinning and successive ionic layer adsorption and reaction process. • Pouous TiO{sub 2} nanofibers decorated CdS nanoparticles. • Synergetic effect of photosensitization and heterojunction. - Abstract: 1D porous CdS nanoparticles/TiO{sub 2} nanofibers heterostructure has been fabricated via simple electrospinning and a successive ionic layer adsorption and reaction (SILAR) process. The morphology, composition, and optical properties of the resulting CdS/TiO{sub 2} heterostructures can be rationally tailored through changing the SILAR cycles. The photocatalytic hydrogen evolution and decomposition of rhodamine B (RhB) of the as-synthesized heterostructured photocatalysts were investigated under visible light irradiation. Compared to TiO{sub 2} nanofibers,the as-obtained CdS/TiO{sub 2} heterostructures exhibit enhanced photocatalytic activity for hydrogen production and decomposition of RhB under visible-light irradiation. The heterojunction system performs best with H{sub 2} generation rates of 678.61 μmol h{sup −1} g{sup −1} under visible light irradiation which benefits from the two effects: (a) the 1D porous nanofibrous morphology contributes to not only more active sites but also more efficient transfer of the photogenerated charges (b) the synergetic effect of heterojunction and photosensitization reducing the recombination of photogenerated electrons and holes.

  15. CdS nanoparticles/CeO{sub 2} nanorods composite with high-efficiency visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    You, Daotong; Pan, Bao; Jiang, Fan; Zhou, Yangen; Su, Wenyue, E-mail: suweny@fzu.edu.cn

    2016-02-15

    Graphical abstract: Coupling CdS with CeO{sub 2} can effectively improve the light-harvesting ability of wide-band gap CeO{sub 2} NRs as the photoinduced electrons on the conduction band of CdS are transfered to the conduction band of CeO{sub 2}. - Highlights: • Coupling CdS can effectively improve the light-harvesting ability of wide-band gap CeO{sub 2}. • CdS/CeO{sub 2} composites show high photocatalytic activity under visible light irradiation. • The mechanism of photocatalytic H{sub 2} evolution over CdS/CeO{sub 2} was proposed. - Abstract: Different mole ratios of CdS nanoparticles (NPs)/CeO{sub 2} nanorods (NRs) composites with effective contacts were synthesized through a two-step hydrothermal method. The crystal phase, microstructure, optical absorption properties, electrochemical properties and photocatalytic H{sub 2} production activity of these composites were investigated. It was concluded that the photogenerated charge carriers in the CdS NPs/CeO{sub 2} NRs composite with a proper mole ratio (1:1) exhibited the longest lifetime and highest separation efficiency, which was responsible for the highest H{sub 2}-production rate of 8.4 mmol h{sup −1} g{sup −1} under visible-light irradiation (λ > 420 nm). The superior photocatalytic H{sub 2} evolution properties are attributed to the transfer of visible-excited electrons of CdS NPs to CeO{sub 2} NRs, which can effectively extend the light absorption range of wide-band gap CeO{sub 2} NRs. This work provides feasible routes to develop visible-light responsive CeO{sub 2}-based nanomaterial for efficient solar utilization.

  16. Surface Decorated Zn0.15Cd0.85S Nanoflowers with P25 for Enhanced Visible Light Driven Photocatalytic Degradation of Rh-B and Stability

    Directory of Open Access Journals (Sweden)

    Muneerah Alomar

    2018-02-01

    Full Text Available Decoration of Zn0.15Cd0.85S nanoflowers with P25 for forming P25/Zn0.15Cd0.85S nanocomposite has been successfully synthesized with fine crystallinity by one-step low temperature hydrothermal method. Photocatalytic efficiency of the as-prepared P25/Zn0.15Cd0.85S for the degradation of Rh-B is evaluated under the visible light irradiation. The synthesized composite is completely characterized with XRD, FESEM, TEM, BET, and UV-vis DRS. TEM observations reveal that P25 is closely deposited on the Zn0.15Cd0.85S nanoflowers with maintaining its nanoflower morphology. The photocatalytic activity of the as-obtained photocatalyst shows that the P25/Zn0.15Cd0.85S exhibits very high catalytic activity for degradation of Rh-B under visible light irradiation due to an increasing of the active sites and enhancing the catalyst stability because of the minimum recombination of the photo-induced electrons and holes. Moreover, it is found that the nanocomposite retains its photocatalytic activity even after four cycles. In addition, to explain the mechanism of degradation, scavengers are used to confirm the reactive species. Photo-generated holes and ●OH play a significant role in the visible light of P25/Zn0.15Cd0.85S nanocomposite induced degradation system, but electrons play the most important role.

  17. Design and development of a new generation of UV-visible-light-driven nanosized codoped titanium dioxide photocatalysts and biocides/sporocides, and environmental applications

    Science.gov (United States)

    Hamal, Dambar B.

    For solar environmental remediation, a new generation of nanosized (tests revealed that codoping of titanium dioxide with a metal (1% Ag or 2% Co) and nonmetals (carbon and sulfur) is necessary to achieve high-activities for acetaldehyde degradation under visible light (wavelength > 420 nm). It was concluded that high visible-light-activities for acetaldehyde degradation over codoped titanium dioxide were attributed to an interplay of anatase crystallinity, high-surface area, reduced band-gap (coli cells and Bacillus subtilis spores). Biocidal tests revealed that silver, carbon, and sulfur codoped titanium dioxide nanoparticles (antimicrobial actions on both E. coli (logarithmic kill > 8) and B. subtilis spores (logarithmic kill > 5) for 30 minute exposures in dark conditions compared with Degussa P25. It was believed that the carbon and sulfur codoped titanium dioxide support and Ag species acted synergistically during deactivation of both E. coli and B. subtilis spores. Thus, titanium dioxide codoped with silver, carbon, sulfur can serve as a multifunctional generic biocide and a visible-light-active photocatalyst.

  18. Palladium nanoparticles anchored to anatase TiO2 for enhanced surface plasmon resonance-stimulated, visible-light-driven photocatalytic activity

    Directory of Open Access Journals (Sweden)

    Kah Hon Leong

    2015-02-01

    Full Text Available Freely assembled palladium nanoparticles (Pd NPs on titania (TiO2 nano photocatalysts were successfully synthesized through a photodeposition method using natural sunlight. This synthesized heterogeneous photocatalyst (Pd/TiO2 was characterized through field emission scanning electron microscopy (FESEM, high resolution transmission electron microscopy (HRTEM, X-ray diffraction (XRD, BET surface area, UV–vis diffuse reflectance spectra (UV-DRS, Raman and photoluminescence (PL analyses. The simple and smart synthesis anchored well the deposition with controlled Pd NPs size ranging between 17 and 29 nm onto the surface of TiO2. Thus, it gives the characteristic for Pd NPs to absorb light in the visible region obtained through localized surface plasmon resonance (LSPRs. Apparently, the photocatalytic activity of the prepared photocatalysts was evaluated by degrading the endocrine disrupting compound (EDC amoxicillin (AMX excited under an artificial visible light source. In the preliminary run, almost complete degradation (97.5% was achieved in 5 h with 0.5 wt % Pd loading and the degradation followed pseudo-first-order kinetics. The reusability trend proved the photostability of the prepared photocatalysts. Hence, the study provides a new insight about the modification of TiO2 with noble metals in order to enhance the absorption in the visible-light region for superior photocatalytic performance.

  19. Achieving enhanced visible-light-driven photocatalysis using type-II NaNbO3/CdS core/shell heterostructures.

    Science.gov (United States)

    Kumar, Sandeep; Khanchandani, Sunita; Thirumal, Meganathan; Ganguli, Ashok K

    2014-08-13

    Expanding the light-harvesting range and suppressing the quick recombination of photogenerated charge carriers are of paramount significance in the field of photocatalysis. One possible approach to achieve wide absorption range is to synthesize type-II core/shell heterostructures. In addition, this system also shows great promise for fast separation of charge carriers and low charge recombination rate. Herein, following the surface functionalization method using 3-mercaptopropionic acid (MPA) as a surface functionalizing agent, we report on designing NaNbO3/CdS type-II core/shell heterostructures with an absorption range extending to visible range and explore the opportunity toward degradation of methylene blue (MB) dye as a model pollutant under visible light irradiation. Characterizations including X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), UV-vis diffuse reflectance spectrum (DRS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy support the growth of CdS shell onto NaNbO3 nanorods. The resulting core/shell heterostructures unveiled high surface areas, enhanced light harvesting, and appreciably increased photocatalytic activity toward MB degradation compared to individual counterparts and the photocatalytic standard, Degussa P25, under visible light irradiation. The remarkably enhanced photocatalytic activity of core/shell heterostructures could be interpreted in terms of efficient charge separation owing to core/shell morphology and resulting type-II band alignment between NaNbO3 and CdS, which creates a step-like radial potential favoring the localization of one of the carriers in the core and the other in the shell. A plausible mechanism for the degradation of MB dye over NaNbO3/CdS core/shell heterostructures is also elucidated using active species scavenger studies. Our findings imply that hydroxyl radicals (OH(•)) play a crucial role in dictating the degradation

  20. Visible-Light-Driven Photoelectrochemical and Photocatalytic Performance of NaNbO3 /Ag2 S Core-Shell Heterostructures.

    Science.gov (United States)

    Kumar, Sandeep; Singh, Aadesh P; Bera, Chandan; Thirumal, Meganathan; Mehta, B R; Ganguli, Ashok K

    2016-07-21

    Herein, we report the fabrication of visible-light-active NaNbO3 /Ag2 S staggered-gap core-shell semiconductor heterostructures with excellent photoelectrochemical activity toward water splitting, and the degradation of a model pollutant (methylene blue) was also monitored. The heterostructures show a pronounced photocurrent density of approximately 2.44 mA cm(-2) at 0.9 V versus Ag/AgCl in 0.5 m Na2 SO4 and exhibit a positive shift in onset potential by approximately 1.1 V. The high photoactivity is attributed to the efficient photoinduced interfacial charge transfer (IFCT). The core-shell design alleviates the challenges associated with the electron-hole paths across semiconductor junctions and at the electrolyte-semiconductor interface. These properties demonstrate that NaNbO3 /Ag2 S core-shell heterostructures show promising visible-light photoactivity and are also efficient, stable, and recyclable photocatalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A robust visible-light driven BiFeWO6/BiOI nanohybrid with efficient photocatalytic and photoelectrochemical performance

    Science.gov (United States)

    Malathi, A.; Arunachalam, Prabhakarn; Grace, Andrews Nirmala; Madhavan, J.; Al-Mayouf, Abdullah M.

    2017-08-01

    In this work, an efficient visible-light active BiFeWO6/BiOI nanocomposite was fabricated by mixing various weight percentages (1%, 2% and 3%) of BiFeWO6 on BiOI via facile one-step wet impregnation method. The synthesized BiFeWO6/BiOI nanocomposite were investigated by XRD, FT-IR, FE-SEM, HR-TEM, EDAX, UV-vis DRS and BET. The photocatalytic activity of synthesized BiFeWO6/BiOI nanocomposite photocatalysts were assessed for the photodegradation of Rhodamine B (RhB) under visible-light illumination. The optimum 1% BiFeWO6/BiOI nanocomposite showed 92% efficiency of RhB after 90 min. The photoluminescence (PL) and photoelectrochemical measurements revealed that the 1% BiFeWO6/BiOI nanocomposite greatly enhanced the charge carrier separation and thus by slowing down the recombination rate of the photoinduced charge carriers. The radical trapping experiment inferred the h+ and O2rad - as the important active species responsible for the photodegradation of RhB. The higher photocatalytic activity and recyclability revealed that the BiFeWO6/BiOI nanocomposite could be a promising material in wastewater treatment and other environmental remediation applications.

  2. Well-crystalline porous ZnO-SnO2 nanosheets: an effective visible-light driven photocatalyst and highly sensitive smart sensor material.

    Science.gov (United States)

    Lamba, Randeep; Umar, Ahmad; Mehta, S K; Kansal, Sushil Kumar

    2015-01-01

    This work demonstrates the synthesis and characterization of porous ZnO-SnO2 nanosheets prepared by the simple and facile hydrothermal method at low-temperature. The prepared nanosheets were characterized by several techniques which revealed the well-crystallinity, porous and well-defined nanosheet morphology for the prepared material. The synthesized porous ZnO-SnO2 nanosheets were used as an efficient photocatalyst for the photocatalytic degradation of highly hazardous dye, i.e., direct blue 15 (DB 15), under visible-light irradiation. The excellent photocatalytic degradation of prepared material towards DB 15 dye could be ascribed to the formation of ZnO-SnO2 heterojunction which effectively separates the photogenerated electron-hole pairs and possess high surface area. Further, the prepared porous ZnO-SnO2 nanosheets were utilized to fabricate a robust chemical sensor to detect 4-nitrophenol in aqueous medium. The fabricated sensor exhibited extremely high sensitivity of ~ 1285.76 µA/mmol L(-1)cm(-2) and an experimental detection limit of 0.078 mmol L(-1) with a linear dynamic range of 0.078-1.25 mmol L(-1). The obtained results confirmed that the prepared porous ZnO-SnO2 nanosheets are potential material for the removal of organic pollutants under visible light irradiation and efficient chemical sensing applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Characteristics of N-doped TiO{sub 2} nanotube arrays by N{sub 2}-plasma for visible light-driven photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xu [College of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Liu Zhongqing, E-mail: 301zql@vip.sina.com [College of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Zheng Jian; Yan Xin; Li Dandan; Chen Si [College of Chemical Engineering, Sichuan University, Chengdu 610065 (China); Chu Wei, E-mail: chuwei1965_scu@yahoo.com [College of Chemical Engineering, Sichuan University, Chengdu 610065 (China)

    2011-10-13

    Highlights: > A new pathway is provided to prepare N-doped TiO2 nanotube arrays using N{sub 2}-plasma treatment. > N{sub 2}-plasma treatment did not wreck the structure of nanotube arrays. > Nitrogen doping promoted the phase transition to rutile phase at low annealing temperatures > Nitrogen doping narrow band gap of TiO{sub 2} and improve the photocatalytic activity of samples. - Abstract: N-doped TiO{sub 2} nanotube arrays were prepared by electrochemical anode oxidation of Ti foil followed by treatment with N{sub 2}-plasma and subsequent annealed under Ar atmosphere. The morphologies, composition and optical properties of N-doped TiO{sub 2} nanotube arrays were characterized using field-emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectrometer (XRD), Photoluminescence (PL) and UV-vis diffusion reflection spectroscopy (UV-vis DRS). Methylene blue (MB) solution was utilized as the degradation model to evaluate the photocatalytic activity of the samples under visible light irradiation. The results suggested N{sub 2}-plasma treatment created doping of nitrogen onto the surface of photoelectrodes successfully and the N-doped TiO{sub 2} nanotube arrays display a significantly enhancement of the photocatalytic activity comparing with the pure TiO{sub 2} nanotube arrays under the visible light irradiation.

  4. Visible light-driven novel nanocomposite (BiVO4/CuCr2O4) for efficient degradation of organic dye.

    Science.gov (United States)

    Bajaj, Rohit; Sharma, Madhulika; Bahadur, D

    2013-05-21

    In the present study, BiVO4/CuCr2O4 nanocomposites synthesized via a chemical route are applied as a photocatalyst for the degradation of methylene blue (MB) dye. The photocatalytic activity results indicated a substantial degradation of MB dye by ~90% over the surface of nanocomposite catalyst under visible light illumination. The nanocomposite showed a photocatalytic activity for MB dye degradation which is three times higher compared to that of BiVO4. This has been attributed to photogenerated electron-hole pair charge separation. The prepared photocatalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis absorption and photoluminescence spectroscopy. Furthermore, an oxidizing reagent such as H2O2 was added to the photocatalytic system, which may act as an alternative electron scavenger and resulting in a notably enhanced rate of pollutant destruction. In addition, the effect of polyaniline has also been studied by synthesizing an organic/inorganic hybrid material (BiVO4/CuCr2O4/PANI). It has been observed that 95% photodegradation of organic dye takes place on the nanocomposite surface with visible light. A possible mechanism explaining the origin of enhanced performance of nanocomposite and nanohybrid is proposed.

  5. A new route for visible/near-infrared-light-driven H2 production over titania: Co-sensitization of surface charge transfer complex and zinc phthalocyanine

    Science.gov (United States)

    Zhang, Xiaohu; Peng, Bosi; Peng, Tianyou; Yu, Lijuan; Li, Renjie; Zhang, Jing

    2015-12-01

    This work introduces a new strategy for visible/near-infrared (NIR) light responsive H2 production over TiO2 nanoparticles co-sensitized with zinc phthalocyanine derivative (Zn-tri-PcNc) and surface ligand-to-metal charge transfer (LMCT) complex, which is in situ formed on the TiO2 nanoparticles' surfaces by using ascorbic acid (AA). The in situ formed surface LMCT complex (AA-TiO2) exhibits obvious visible-light-responsive photoactivity (126.2 μmol/h) for H2 production with a high apparent quantum yield (AQY) of 16.1% at 420 nm monochromatic light irradiation. Moreover, the co-sensitized TiO2 nanoparticles (Zn-tri-PcNc-TiO2-AA) shows a much higher photoactivity (162.2 μmol/h) for H2 production than the surface LMCT complex, and broader spectral responsive region (400-800 nm) with a relatively high AQY value (0.97%) at 700 nm monochromatic light irradiation. The present result reveals a possible substitute for the conventional Ru(II)-bipyridyl complexes or organic dyes as sensitizer of semiconductors in the field of solar fuel conversion.

  6. Preparation of α-SnWO{sub 4}/SnO{sub 2} heterostructure with enhanced visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Shiyue; Zhang, Min; Di, Junwei; Wang, Zuoshan [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Long, Yumei, E-mail: Yumeilong@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou (China); Li, Weifeng, E-mail: liweifeng@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

    2015-12-01

    Graphical abstract: SnO{sub 2}-hybridized α-SnWO{sub 4} nanocomposites were prepared and they exhibited favorable photocatalytic activity for the degradation of MO under visible light irradiation. A detailed photocatalytic mechanism based on heterostructure was given. - Highlights: • α-SnWO{sub 4}/SnO{sub 2} heterostructure was prepared by a two-step hydrothermal route. • The attachment of SnO{sub 2} nanocrystals on α-SnWO{sub 4} nanoplates increases BET surface area. • The α-SnWO{sub 4}/SnO{sub 2} heterojunction efficiently hinders the recombination of photogenerated electrons and holes. • α-SnWO{sub 4}/SnO{sub 2} nanocomposite exhibits excellent photocatalytic activity under visible light irradiation. - Abstract: In this work, a novel α-SnWO{sub 4}/SnO{sub 2} heterostructure was synthesized via a facile two-step hydrothermal method. The as-prepared products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scan electron microscopy (SEM) and transmission electron microscopy (TEM), which confirmed the typical orthorhombic α-SnWO{sub 4} phase, plate-like morphology and α-SnWO{sub 4}/SnO{sub 2} heterostructure. The photocatalytic studies revealed that the attachment of SnO{sub 2} nanoparticles on the surface of α-SnWO{sub 4} plates can remarkably improve their photocatalytic activities and the α-SnWO{sub 4}/SnO{sub 2} heterostructure exhibited the best photocatalytic properties in the degradation of methyl orange (MO) under visible light irradiation. The degradation rate of MO on α-SnWO{sub 4}/SnO{sub 2} plate was 97% within 40 min and the photocatalytic degradation reaction followed the pseudo-first-order kinetics. The enhanced photocatalytic property was ascribed to the large surface area and the heterojuction between α-SnWO{sub 4} and SnO{sub 2}, which can facilitate efficient charge separation of photogenerated electron–hole pairs. Furthermore, α-SnWO{sub 4}/SnO{sub 2} nanocomposite demonstrated good

  7. Narrow band gap and visible light-driven photocatalysis of V-doped Bi{sub 6}Mo{sub 2}O{sub 15} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jian; Qin, Chuanxiang; Huang, Yanlin [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Wang, Yaorong, E-mail: yrwang@suda.edu.cn [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Qin, Lin [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2017-02-28

    Highlights: • V{sup 5+}-doped Bi{sub 6}Mo{sub 2}O{sub 15} was synthesized by the electrospinning preparation. • The band gap energy of Bi{sub 6}Mo{sub 2}O{sub 15} was greatly reduced by V-doping in the lattices. • V-doped Bi{sub 6}Mo{sub 2}O{sub 15} shows high activity in RhB degradation under visible light. • Crystal structure of Bi{sub 6}Mo{sub 2}O{sub 15} is favorable for high photocatalytic capacity. - Abstract: Pure and V{sup 5+}-doped Bi{sub 6}Mo{sub 2}O{sub 15} (3Bi{sub 2}O{sub 3}·2MoO{sub 3}) photocatalysts were synthesized through electrospinning, followed by low-temperature heat treatment. The samples developed into nanoparticles with an average size of approximately 50 nm. The crystalline phases were verified via X-ray powder diffraction measurements (XRD). The surface properties of the photocatalysts were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analyses. The UV–vis spectra showed that V doping in Bi{sub 6}Mo{sub 2}O{sub 15} shifted the optical absorption from the UV region to the visible-light wavelength region. The energy of the band gap of Bi{sub 6}Mo{sub 2}O{sub 15} was reduced by V doping in the lattices. The photocatalytic activities of the pure and V-doped Bi{sub 6}Mo{sub 2}O{sub 15} were tested through photodegradation of rhodamine B (RhB) dye solutions under visible light irradiation. Results showed that 20 mol% V-doped Bi{sub 6}Mo{sub 2}O{sub 15} achieved efficient photocatalytic ability. RhB could be degraded by V-doped Bi{sub 6}Mo{sub 2}O{sub 15} in 2 h. The photocatalytic activities and mechanisms were discussed according to the characteristics of the crystal structure and the results of EIS and XPS measurements.

  8. Hydrothermal synthesis of InVO{sub 4}/Graphitic carbon nitride heterojunctions and excellent visible-light-driven photocatalytic performance for rhodamine B

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Weilong; Guo, Feng [Key Laboratory of Preparation and Application Environmentally Friendly Materials of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin Province (China); Chen, Jibin [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu Province (China); Che, Guangbo [Key Laboratory of Preparation and Application Environmentally Friendly Materials of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin Province (China); Lin, Xue, E-mail: jlsdlinxue@126.com [Key Laboratory of Preparation and Application Environmentally Friendly Materials of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin Province (China)

    2014-11-05

    Highlights: • InVO{sub 4}/g-C{sub 3}N{sub 4} composites with high photocatalytic activity were successfully synthesized through a facile hydrothermal method. • InVO{sub 4}/g-C{sub 3}N{sub 4} samples were characterized by various characterization technologies. • InVO{sub 4}/g-C{sub 3}N{sub 4} samples presented outstanding visible-light-induced photocatalytic performance. - Abstract: In this work, n-type graphite-like C{sub 3}N{sub 4} (denoted as g-C{sub 3}N{sub 4}) was fabricated and modified with p-type Indium vanadate (InVO{sub 4}) to form a novel InVO{sub 4}/g-C{sub 3}N{sub 4}p–n heterojunction photocatalyst for the efficient photocatalytic degradation of rhodamine B (Rh B). The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activities were evaluated in the degradation of Rh B aqueous solution. The results showed that the as-prepared InVO{sub 4}/g-C{sub 3}N{sub 4} hybrid materials displayed much higher photocatalytic activity than the pure g-C{sub 3}N{sub 4} and InVO{sub 4} particles. Among them, the 30 wt% InVO{sub 4}/g-C{sub 3}N{sub 4} sample exhibited the highest photocatalytic activity. The visible-light photocatalytic activity enhancement of InVO{sub 4}/g-C{sub 3}N{sub 4} heterojunction photocatalyst could be attributed to its strong absorption in the visible region and low recombination rate of the electron–hole pairs. It was further found that the photodegradation of Rh B molecules is mainly attributed to the oxidation action of the generated O{sub 2}{sup ·-} radicals and partly to the oxidation process of {sup ·}OH radicals.

  9. Surface plasmon resonance enhanced visible-light-driven photocatalytic activity in Cu nanoparticles covered Cu{sub 2}O microspheres for degrading organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yahui, E-mail: chengyahui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Lin, Yuanjing [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Xu, Jianping [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); He, Jie; Wang, Tianzhao; Yu, Guojun; Shao, Dawei; Wang, Wei-Hua; Lu, Feng [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Li, Lan [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); Du, Xiwen [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Wang, Weichao [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Liu, Hui, E-mail: liuhui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Zheng, Rongkun [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2016-03-15

    Graphical abstract: - Highlights: • Cu NPs introduce the SPR and result in an increase of visible light absorption. • The photocatalytic activity of Cu{sub 2}O/Cu improves greatly due to the SPR effect. • A dark catalytic activity is observed stemming from the Fenton-like reaction. • The • O{sub 2}{sup −} and • OH radicals contribute to the photocatalytic process. • The • OH radicals contribute to the dark catalytic process. - Abstract: Micron-sized Cu{sub 2}O with different coverage of Cu nanoparticles (NPs) on the sphere has been synthesized by a redox procedure. The absorption spectra show that Cu NPs induce the surface plasmon resonance (SPR) at the wavelength of ∼565 nm. Methylene blue (MB) photodegrading experiments under visible-light display that the Cu{sub 2}O–Cu–H{sub 2}O{sub 2} system exhibits a superior photocatalytic activity to Cu{sub 2}O–H{sub 2}O{sub 2} or pure H{sub 2}O{sub 2} with an evident dependency on Cu coverage. The maximum photodegradation rate is 88% after visible-light irradiating for 60 min. The role of the Cu NPs is clarified through photodegradation experiments under 420 nm light irradiation, which is different from the SPR wavelength of Cu NPs (∼565 nm). By excluding the SPR effect, it proves that Cu SPR plays a key role in the photodegradation. Besides, a dark catalytic activity is observed stemming from the Fenton-like reaction with the aid of H{sub 2}O{sub 2}. The radical quenching experiments indicate that both • O{sub 2}{sup −} and • OH radicals contribute to the photocatalysis, while the dark catalysis is only governed by the • OH radicals, leading to a lower activity comparing with the photocatalysis. Therefore, with introducing Cu NPs and H{sub 2}O{sub 2}, the Cu{sub 2}O-based photocatalytic activity could be significantly improved due to the SPR effect and dark catalysis.

  10. Enhanced visible-light-driven photocatalytic inactivation of Escherichia coli using g-C3N4/TiO2 hybrid photocatalyst synthesized using a hydrothermal-calcination approach.

    Science.gov (United States)

    Li, Guiying; Nie, Xin; Chen, Jiangyao; Jiang, Qi; An, Taicheng; Wong, Po Keung; Zhang, Haimin; Zhao, Huijun; Yamashita, Hiromi

    2015-12-01

    Biohazards are widely present in wastewater, and contaminated water can arouse various waterborne diseases. Therefore, effectively removing biohazards from water is a worldwide need. In this study, a novel visible-light-driven (VLD) graphitic carbon nitride (g-C3N4)/TiO2 hybrid photocatalyst with high photocatalytic bacterial inactivation activity was successfully synthesized using a facile hydrothermal-calcination approach. The optimum synthesized hybrid photocatalyst is composed of micron-sized TiO2 spheres (average diameter: ca. 2 μm) and wrapped with lamellar g-C3N4 (thickness: ca. 2 nm), with narrowing bandgap (ca. 2.48 eV), leading to a significant improvement of visible light (VL) absorption and effective separation of photo-generated electron-hole pairs. This greatly enhances VL photocatalytic inactivation activity towards bacteria in water. Using this hybrid photocatalyst, 10(7) cfu mL(-1) of Escherichia coli K-12 could be completely inactivated within 180 min under VL irradiation. SEM images indicate that bacterial cells were greatly damaged, leading to a severe leakage of intracellular components during photocatalytic inactivation processes. The study concludes that bacterial cell destruction and water disinfection can be achieved using this newly fabricated VLD hybrid photocatalyst. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Fabrication of 3D quasi-hierarchical Z-scheme RGO-Fe2O3-MoS2 nanoheterostructures for highly enhanced visible-light-driven photocatalytic degradation

    Science.gov (United States)

    Chen, Lixia; He, Fang; Zhao, Naiqin; Guo, Ruisong

    2017-10-01

    3D quasi-hierarchical Z-scheme RGO-Fe2O3-MoS2 nanocomposites were developed as a high performance photocatalyst driven by visible light. The RGO layers help uniformly disperse α-Fe2O3 NPs and MoS2 nanosheets, resulting in large specific surface area of the nanocomposites. Moreover, when involved in photocatalytic process for MB degradation, the RGO layers not only serve as current collector to enhance the photo-generated charge carriers' transport but also form abundant heterostructures with Fe2O3 and MoS2 to effectively separate the photo-induced electron-hole pairs. The Fesbnd Osbnd C bonds are formed between Fe2O3 and RGO, implying the intimate interface contact which can accelerate the separation of photogenerated carriers. Moreover, the loading of MoS2 nanosheets, which contributes to large amount of light absorption, is conducive to create a plenty of heterojunctions with Fe2O3 and effectively separate photo-induced electron-hole pairs. As a result, the typical Z-scheme RGO-Fe2O3-MoS2 nanocomposites containing 62.1 wt% of α-Fe2O3 and 15.2 wt% of MoS2 show drastically enhanced photocatalytic activity for visible-light-driven MB and RhB degradation compared to the pristine Fe2O3 NPs, and together with excellent stability.

  12. Dye-sensitized MIL-101 metal organic frameworks loaded with Ni/NiOx nanoparticles for efficient visible-light-driven hydrogen generation

    Directory of Open Access Journals (Sweden)

    Xin-Ling Liu

    2015-10-01

    Full Text Available The Ni/NiOx particles were in situ photodeposited on MIL-101 metal organic frameworks as catalysts for boosting H2 generation from Erythrosin B dye sensitization under visible-light irradiation. The highest H2 production rate of 125 μmol h−1 was achieved from the system containing 5 wt. % Ni-loaded MIL-101 (20 mg and 30 mg Erythrosin B dye. Moreover, the Ni/NiOx catalysts show excellent stability for long-term photocatalytic reaction. The enhancement on H2 generation is attributed to the efficient charge transfer from photoexcited dye to the Ni catalyst via MIL-101. Our results demonstrate that the economical Ni/NiOx particles are durable and active catalysts for photocatalytic H2 generation.

  13. Dye-sensitized MIL-101 metal organic frameworks loaded with Ni/NiO{sub x} nanoparticles for efficient visible-light-driven hydrogen generation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xin-Ling; Wang, Rong; Yuan, Yu-Peng, E-mail: yupengyuan@ahu.edu.cn, E-mail: cxue@ntu.edu.sg [School of Chemistry and Chemical Engineering, and Innovation Lab for Clean Energy and Green Catalysis, Anhui University, Hefei 230036 (China); Zhang, Ming-Yi [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025 (China); Xue, Can, E-mail: yupengyuan@ahu.edu.cn, E-mail: cxue@ntu.edu.sg [Solar Fuels Lab, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2015-10-01

    The Ni/NiO{sub x} particles were in situ photodeposited on MIL-101 metal organic frameworks as catalysts for boosting H{sub 2} generation from Erythrosin B dye sensitization under visible-light irradiation. The highest H{sub 2} production rate of 125 μmol h{sup −1} was achieved from the system containing 5 wt. % Ni-loaded MIL-101 (20 mg) and 30 mg Erythrosin B dye. Moreover, the Ni/NiO{sub x} catalysts show excellent stability for long-term photocatalytic reaction. The enhancement on H{sub 2} generation is attributed to the efficient charge transfer from photoexcited dye to the Ni catalyst via MIL-101. Our results demonstrate that the economical Ni/NiO{sub x} particles are durable and active catalysts for photocatalytic H{sub 2} generation.

  14. Enhanced visible light-driven photocatalytic performance of ZnO-g-C3N4 coupled with graphene oxide as a novel ternary nanocomposite.

    Science.gov (United States)

    Jo, Wan-Kuen; Clament Sagaya Selvam, N

    2015-12-15

    This article reports a novel ternary nanocomposite consisting of ZnO, g-C3N4, and graphene oxide (GO) that provides enhanced photocatalytic performance and stability. The ZnO nanospheres disperse evenly and embed themselves in the porous g-C3N4. Composites with various g-C3N4 and GO to ZnO weight ratios were synthesized and characterized systematically. The results indicated that the absorption of binary g-C3N4/ZnO nanocomposites shifted to a lower energy compared to pure ZnO in a fashion consistent with the loading content of g-C3N4. Notably, the loading content of GO in the ZnO-g-C3N4 composite resulted in increased absorption in the visible range and improved charge separation efficiency, thereby drastically improving photocatalytic activity. Successful hybridization of ternary nanocomposite was confirmed by drastic quenching of fluorescence and broader visible light absorption. The optimal content of g-C3N4 in the ZnO-g-C3N4 composite was 50%, which exhibited the effective hybridization between ZnO and g-C3N4, and high photocatalytic efficiency. However, the photocatalytic degradation of the ternary nanocomposite showed performance that was two times greater than ZnO-g-C3N4, exhibiting 99.5% degradation efficiency after just 15 min of light irradiation. The combined heterojunction and synergistic effects of this composite account for the improved photocatalytic activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Visible-light-driven photocatalytic inactivation of MS2 by metal-free g-C3N4: Virucidal performance and mechanism.

    Science.gov (United States)

    Li, Yi; Zhang, Chi; Shuai, Danmeng; Naraginti, Saraschandra; Wang, Dawei; Zhang, Wenlong

    2016-12-01

    The challenge to achieve effective water disinfection of pathogens, especially viruses, with minimized harmful disinfection byproducts calls for a cost-effective and environmentally benign technology. Here, polymeric graphitic carbon nitride (g-C3N4), as a metal-free robust photocatalyst, was explored for the first time for its ability to inactivate viruses under visible light irradiation. MS2 with an initial concentration of 1 × 10(8) PFU/mL was completely inactivated by g-C3N4 with a loading of 150 mg/L under visible light irradiation of 360 min. g-C3N4 was a robust photocatalyst, and no decrease in its virucidal performance was observed over five cycles of sequential MS2 photocatalytic inactivation. The reactive oxygen species (ROSs) were measured by a range of scavengers, and photo-generated electrons and its derived ROSs (O- 2) were found to be the leading contributor for viral inactivation. TEM images indicated that the viral particle shape was distorted and the capsid shell was ruptured after photocatalysis. Viral surface proteins, particularly replicase proteins and maturation proteins, were damaged by photocatalytic oxidation. The loss of proteins would result in the leakage and rapid destruction of interior components (four main types of RNA genes), finally leading to viral death without regrowth. Our work opens a new avenue for the exploration and applications of a low-cost, high-efficient, and robust metal-free photocatalyst for green/sustainable viral disinfection. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Hierarchical Bi{sub 2}WO{sub 6} architectures decorated with Pd nanoparticles for enhanced visible-light-driven photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinniu; Chen, Tianhua [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Lu, Hongbing, E-mail: hblu@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Yang, Zhibo; Yin, Feng; Gao, Jianzhi; Liu, Qianru [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710062 (China); Tu, Yafang [Department of Physics, Institute for Interdisciplinary Research, Jianghan University, Wuhan, 430056 (China)

    2017-05-15

    Highlights: • A new kind of Pd decorated Bi{sub 2}WO{sub 6} hierarchical microarchitecture was synthesized. • Pd nanoparticles remarkably improved the photocatalytic activity of Bi{sub 2}WO{sub 6}. • The photo-generated holes and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. • The photocatalytic enhancement mechanism of the Pd-Bi{sub 2}WO{sub 6} composites was proposed. - Abstract: A new kind of hierarchical Pd-Bi{sub 2}WO{sub 6} architecture decorated with different molar ratios of Pd to Bi, has been fabricated by a hydrothermal process, followed by a chemical deposition method. The photocatalytic activities of the pure Bi{sub 2}WO{sub 6} and Pd-Bi{sub 2}WO{sub 6} nanocatalyst were examined in the degradation of Rhodamine B (RhB) dyes and phenol under visible light. The photocatalytic results showed that the Pd-Bi{sub 2}WO{sub 6} nanocomposites possessed observably enhanced photocatalytic activities. Particularly, the 2.0% Pd loaded Bi{sub 2}WO{sub 6} had the highest photocatalytic activity, exhibiting a nearly complete degradation of 30 mg/L RhB and 10 mg/L phenol within only 50 and 60 min, respectively. In addition, the trapping experiment results indicated that the photo-generated holes (h{sup +}) and ·O{sub 2}{sup −} played a crucial role in the degradation of RhB. According to the experimental results, the photocatalytic degradation mechanism of Pd-Bi{sub 2}WO{sub 6} was also proposed. The enhanced photocatalytic activities were ascribed to the combined effects of the highly efficient separation of electrons and holes, improved visible light utilization and increased BET specific surface areas of the Pd-Bi{sub 2}WO{sub 6} nanocomposites.

  17. Preparation of efficient visible-light-driven BiOBr/Bi{sub 2}O{sub 3} heterojunction composite with enhanced photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qizhao, E-mail: qizhaosjtu@gmail.com [College of Chemistry and Chemical Engineering, Northwest Normal University, Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Gansu Polymer Materials, Lanzhou, 730070 (China); Jiao, Danhua; Lian, Juhong; Ma, Qiong; Yu, Jie [College of Chemistry and Chemical Engineering, Northwest Normal University, Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Gansu Polymer Materials, Lanzhou, 730070 (China); Huang, Haohao, E-mail: scuthhh@hotmail.com [College of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640 (China); Zhong, Junbo; Li, Jianzhang [Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education Institutes of Sichuan, College of Chemistry and Pharmaceutical Engineering, Sichuan University of Science and Engineering, Zigong, 643000 (China)

    2015-11-15

    Highly efficient novel photocatalysts BiOBr/Bi{sub 2}O{sub 3} with various proportion of BiOBr were synthesized via accommodating the pH value of solution and were applied to decontaminate methyl orange (MO) and methylene blue (MB). The samples were characterized by Fourier transform infrared spectrophotometry (FT-IR), X-ray diffractometry (XRD), Scanning electron microscopy (SEM), UV–vis diffuse reflectance spectra, and N{sub 2} physisorption. Though both the individual BiOBr and Bi{sub 2}O{sub 3} showed very low photocatalytic efficiency under visible light irradiation, the BiOBr/Bi{sub 2}O{sub 3} composites exhibited superior activity for MO and MB under visible light, and 75% BiOBr/Bi{sub 2}O{sub 3} (pH = 6) composite showed the highest degradation rate, which was 1.4 times than that of pure BiOBr. The photocatalytic activity investigating on MB also showed a same result. In addition, the catalyst can be separated easily for reuse and no obvious loss of photocatalytic activity were observed after three consecutive runs. - Highlights: • Highly efficient novel photocatalysts BiOBr/Bi{sub 2}O{sub 3} with various proportions of BiOBr were synthesized via a facile hydrolysis. • Investigating the influence of photocatalysts on the degradation of MO by accommodating pH values. • The mechanism was proposed based on the synergistic effect between BiOBr and Bi{sub 2}O{sub 3}.

  18. Biomolecule-mediated CdS-TiO2-reduced graphene oxide ternary nanocomposites for efficient visible light-driven photocatalysis.

    Science.gov (United States)

    Dutta, Soumen; Sahoo, Ramakrishna; Ray, Chaiti; Sarkar, Sougata; Jana, Jayasmita; Negishi, Yuichi; Pal, Tarasankar

    2015-01-07

    We report an environmentally friendly synthetic strategy to fabricate reduced graphene oxide (rGO)-based ternary nanocomposites, in which glutathione (GSH) acts both as a reducing agent for graphene oxide and sulfur donor for CdS synthesis under modified hydrothermal (MHT) conditions. The report becomes interesting as pH variation evolves two distinctly different semiconducting nanocrystals of anatase/rutile TiO2 and hexagonal yellow/cubic red CdS, and their packaging makes them suitable photocatalysts for dye degradation. Herein, a titanium peroxo compound, obtained from commercial TiO2, is hydrolyzed to TiO2 nanostructures without any additives. The yellow colored CdS-TiO2-rGO (YCTG), one of the ternary photocatalysts, shows maximum efficiency compared to the corresponding red ternary CdS-TiO2-rGO or binary photocatalysts (CdS-rGO, TiO2-rGO and CdS-TiO2) for dye degradation under visible light irradiation. Systematic characterizations reveal that TiO2 presents at the interface of rGO and CdS in YCTG and thus makes a barrier that inhibits the direct interaction between rGO and CdS. This leads to a relatively higher bandgap value for CdS in YCTG (2.15 eV vs. 2.04 eV for CdS-rGO) but with better photocatalytic activity simply by diminishing the possibility of the charge-recombination process. In the present situation, rGO in the YCTG also supports faster dye degradation through higher dye adsorption and rapid internal electron transfer (CdS→TiO2→rGO) in the YCTG nanocomposite. Thus, a simple aqueous phase and a greener synthetic procedure results in a low-cost, highly effective visible light-responsive material for environmental application.

  19. Visible light driven photocatalysis and antibacterial activity of AgVO{sub 3} and Ag/AgVO{sub 3} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anamika [Department of Life Sciences, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Dutta, Dimple P., E-mail: dimpled@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ballal, A. [Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Fulekar, M.H. [School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar 382 030, Gujarat (India)

    2014-03-01

    Graphical abstract: - Highlights: • Ag/AgVO{sub 3} and pure AgVO{sub 3} nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO{sub 3} within 45 min. • Antibacterial activity of Ag/AgVO{sub 3} demonstrated. - Abstract: Ag/AgVO{sub 3} nanowires and AgVO{sub 3} nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO{sub 3} nanowires. The photocatalytic studies revealed that the Ag/AgVO{sub 3} nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO{sub 3} nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO{sub 3} nanorods prove that in case of the Ag dispersed Ag/AgVO{sub 3} nanowires, the enhanced antibacterial action is also due to contribution from the AgVO{sub 3} support.

  20. Preparation, characterization and visible-light-driven photocatalytic activity of a novel Fe(III) porphyrin-sensitized TiO{sub 2} nanotube photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Meng [National Engineering Lab of Textile Fiber Materials & Processing Technology, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Wan, Junmin, E-mail: wwjm2001@126.com [National Engineering Lab of Textile Fiber Materials & Processing Technology, Zhejiang Sci-Tech University, Hangzhou 310018 (China); State Key Laboratory of advanced Textiles Materials and Manufacture Technology, MOE, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Hu, Zhiwen; Peng, Zhiqin; Wang, Bing [National Engineering Lab of Textile Fiber Materials & Processing Technology, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Wang, Huigang [State Key Laboratory of advanced Textiles Materials and Manufacture Technology, MOE, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

    2017-01-01

    Highlights: • FeTCPP-TNT photocatalysts are synthesized. • FeTCPP and tube-like structure are helpful to induce interfacial charge transfer at surface junction. • FeTCPP and tube-like structure are favorable for enhancing photocatalytic activity. • The photocatalytic mechanism of FeTCPP-TNT is proposed. • The photocatalyst are proven to be effective and chemically-stable catalysts. - Abstract: Iron(III) meso-tetra(4-carboxyphenyl) porphyrin (FeTCPP) loaded on the surface of TiO{sub 2} nanotubes (TNTs) has been successfully prepared through improved hydrothermal and heating reflux process. The new photocatalyst has been characterized and analyzed by TEM/EDS, BET, XRD, FT-IR, DRS, PL, XPS and EPR. The photocatalytic activity of FeTCPP/TNT nanocomposite was evaluated by the photodegradation of MB under visible light irradiation. The degradation results showed a purification of more than 90% MB in simulating wastewater, and confirmed that the prepared FeTCPP/TNT nanocomposite has acquired superior photocatalytic activitiy. The 6 times cycled results suggested the great stability of the photocatalyst. These results confirmed the FeTCPP played an important role in capturing photons and expanding the absorption wavelength to the visible light region, and the FeTCPP/TNT photocatalyst is also beneficial for the electron transfer and long-distance transmission, and could efficiently increase the separation of the electron-hole pairs, and accelerate the decomposition of organic pollutants. In addition, nano-sized structures can increase adsorption capability.

  1. Two-dimensional TiO2-based nanosheets co-modified by surface-enriched carbon dots and Gd2O3 nanoparticles for efficient visible-light-driven photocatalysis

    Science.gov (United States)

    Lu, Dingze; Fang, Pengfei; Ding, Junqian; Yang, Minchen; Cao, Yufei; Zhou, Yawei; Peng, Kui; Kondamareddy, Kiran Kumar; Liu, Min

    2017-02-01

    Two-dimensional TiO2-based nanosheets (TNSs) co-modified by surface-enriched carbon dots (CDs) and Gd2O3 nanoparticles: (Gd-C-TNSs), capable of exhibiting visible-light-driven photo catalysis were synthesized using a two-pot hydrothermal route. The samples had a sheet-like structure, thickness of approximately 3.6 nm, large specific surface area of 240-350 cm2/g. The CDs (2-3 nm) and Gd2O3 nanoparticles (1-2 nm) were highly dispersed over the surface of the nanosheets. The co-modification by Gd2O3 nanoparticles and CDs influenced the crystallinity, crystal structure, and surface area of the TNSs, and improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be improved by an appropriate amount of modification. A very high efficiency was obtained using 0.5 at% Gd/Ti and 3.0 g/L of CDs. The visible-light-induced photocatalytic activity is enhanced under the isolated Cr(VI) system, isolated Rhodamin B (RhB) system, and the synergism between RhB degradation and Cr(VI) reduction for the Gd-C-TNSs photocatalysts. Initially, the photocatalytic activity gradually increased with an increase in the amount of CDs, and then decreased after attaining a maximum, in the case where 0.5 at% Gd/Ti and 3.0 g/L of CDs were used. The enhancement in the photocatalytic activity was attributed to the synergetic effect of the Gd2O3 nanoparticles, TNSs, and CDs in the Gd-C-TNSs composites. The effect led to a fast separation and slow recombination of photo-induced electron-hole pairs. An alternate mechanism for enhanced visible-light photocatalytic activity was also considered.

  2. Self-assembly of ultrathin Cu2MoS4 nanobelts for highly efficient visible light-driven degradation of methyl orange

    Science.gov (United States)

    Zhang, Ke; Chen, Wenxing; Lin, Yunxiang; Chen, Haiping; Haleem, Yasir A.; Wu, Chuanqiang; Ye, Fei; Wang, Tianxing; Song, Li

    2015-10-01

    We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL-1 MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study offers a self-assembled synthetic route to create new multifunctional nanoarchitectures composed of atomic layers, and thus may open a window for greatly extending potential applications in water pollution treatment, photocatalytic water-splitting, solar cells and other related fields.We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL-1 MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study

  3. Incorporation of Cu{sub 2}O nanocrystals into TiO{sub 2} photonic crystal for enhanced UV–visible light driven photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Zhi; Zhang, Yu; Yuan, Xing; Huo, Mingxin; Zhao, Yahui; Lu, Ying, E-mail: luy332@nenu.edu.cn; Qiu, Yue

    2015-09-25

    Highlights: • The Cu{sub 2}O NCs/TiO{sub 2} PC composite was synthesized and exhibited high photocatalysis. • The improved light harvesting and increased quantum yield was achieved. • The hydroxyl radical was the primary oxidant in Cu{sub 2}O NCs/TiO{sub 2} PC photocatalysis. - Abstract: A 3D UV–visible light responsive photocatalyst was fabricated by infiltrating Cu{sub 2}O nanocrystals (NCs) into TiO{sub 2} photonic crystal (PC). Morphology characterization presented that Cu{sub 2}O NCs with average diameter around 10 nm were dispersed uniformly into TiO{sub 2} PC. The transmittance spectra showed that Cu{sub 2}O NCs/TiO{sub 2} 260, prepared by integrating Cu{sub 2}O NCs with TiO{sub 2} 260 which was fabricated from 260 nm polystyrene spheres, exhibited the highest light harvesting. The photoluminescence spectra confirmed the electron/hole pairs recombination of Cu{sub 2}O NCs/TiO{sub 2} 260 was efficiently inhibited due to the unique heterojunction structure between TiO{sub 2} and Cu{sub 2}O. In the photocatalytic degradation of Rhodamine B and Bisphenol A under UV–visible light (320 nm < λ < 780 nm) irradiation, the kinetic constant using Cu{sub 2}O NCs/TiO{sub 2} 260 was 3.99 and 8.37-fold larger than that using TiO{sub 2} nanoparticle (NP), respectively. The enhanced photocatalysis benefited from the increased light harvesting owing to the excitation of both TiO{sub 2} and Cu{sub 2}O NCs whose optical absorption was intensified by the photonic effect of TiO{sub 2} 260 and the high quantum efficiency due to the Cu{sub 2}O/TiO{sub 2} heterojunction. The hydroxyl radical, generated from the protonation of superoxide radical which was derived from the reduction of oxygen by photogenerated electrons, was the main oxidant responsible for pollutant degradation.

  4. Synthesis of hierarchical ZnV2O6 nanosheets with enhanced activity and stability for visible light driven CO2 reduction to solar fuels

    Science.gov (United States)

    Bafaqeer, Abdullah; Tahir, Muhammad; Amin, Nor Aishah Saidina

    2018-03-01

    Hierarchical nanostructures have lately garnered enormous attention because of their remarkable performances in energy storage and catalysis applications. In this study, novel hierarchical ZnV2O6 nanosheets, formulated by one-step solvothermal method, for enhanced photocatalytic CO2 reduction with H2O to solar fuels has been investigated. The structure and properties of the catalysts were characterized by XRD, FESEM, TEM, BET, UV-vis, Raman and PL spectroscopy. The hierarchical ZnV2O6 nanosheets show excellent performance towards photoreduction of CO2 with H2O to CH3OH, CH3COOH and HCOOH under visible light. The main product yield, CH3OH of 3253.84 μmol g-cat-1 was obtained over ZnV2O6, 3.4 times the amount of CH3OH produced over the ZnO/V2O5 composite (945.28 μmol g-cat-1). In addition, CH3OH selectivity of 39.96% achieved over ZnO/V2O5, increased to 48.78% in ZnV2O6 nanosheets. This significant improvement in photo-activity over ZnV2O6 structure was due to hierarchical structure with enhanced charge separation by V2O5. The obtained ZnV2O6 hierarchical nanosheets exhibited excellent photocatalytic stability for selective CH3OH production.

  5. Synthesis of visible light driven cobalt tailored Ag2O/TiON nanophotocatalyst by reverse micelle processing for degradation of Eriochrome Black T

    KAUST Repository

    Hussain, Syed Tajammul

    2013-02-01

    An ultra efficient cobalt tailored silver and nitrogen co-doped titania (TiON/Ag2O/Co) visible nanophotocatalyst is successfully synthesized using modified reverse micelle processing. Composition, phase, distribution of dopants, functional group analysis, optical properties and morphology of synthesized materials are investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) based techniques and others. Charge states of titanium (Ti) and silver are explored through core-loss electron energy loss spectroscopy (EELS) analysis and X ray photoelectron spectroscopy (XPS). Our characterization results showed that the synthesized nanophotocatalyst consisted of anatase phased qausispherical nanoparticles that exhibited homogeneous distribution of dopants, large surface area, high quantum efficiency and enhanced optical properties. At lower content of doped Co ions, the TiON/Ag2O responded with extraordinary photocatalytic properties. The cobalt tailored nanophotocatalyst showed remarkable activity against Eriochrome Black T (EBT). Moreover, comparative degradation behavior of EBT with TiON, Ag2O/TiON and Co/Ag2O/TiON is also investigated. © 2012 Elsevier Ltd.

  6. N-Doped TiO2 Nanobelts with Coexposed (001) and (101) Facets and Their Highly Efficient Visible-Light-Driven Photocatalytic Hydrogen Production.

    Science.gov (United States)

    Sun, Shuchao; Gao, Peng; Yang, Yurong; Yang, Piaoping; Chen, Yujin; Wang, Yanbo

    2016-07-20

    To narrow the band gap (3.2 eV) of TiO2 and extend its practical applicability under sunlight, the doping with nonmetal elements has been used to tune TiO2 electronic structure. However, the doping also brings new recombination centers among the photoinduced charge carriers, which results in a quantum efficiency loss accordingly. It has been proved that the {101} facets of anatase TiO2 are beneficial to generating and transmitting more reductive electrons to promote the H2-evolution in the photoreduction reaction, and the {001} facets exhibit a higher photoreactivity to accelerate the reaction involved of photogenerated hole. Thus, it was considered by us that using the surface heterojunction composed of both {001} and {101} facets may depress the disadvantage of N doping. Fortunately, we successfully synthesized anatase N-doped TiO2 nanobelts with a surface heterojunction of coexposed (101) and (001) facets. As expected, it realized the charge pairs' spatial separation and showed higher photocatalytic activity under a visible-light ray: a hydrogen generation rate of 670 μmol h(-1) g(-1) (much higher than others reported previously in literature of N-doped TiO2 nanobelts).

  7. Self-assembly of ultrathin Cu2MoS4 nanobelts for highly efficient visible light-driven degradation of methyl orange.

    Science.gov (United States)

    Zhang, Ke; Chen, Wenxing; Lin, Yunxiang; Chen, Haiping; Haleem, Yasir A; Wu, Chuanqiang; Ye, Fei; Wang, Tianxing; Song, Li

    2015-11-21

    We demonstrate ultrathin self-assembled Cu2MoS4 nanobelts synthesized by using Cu2O as the starting sacrificial template via a hydrothermal method. The nanobelts exhibit strong light absorption over a broad wavelength spectrum, suggesting their potential application as photocatalysts. The photocatalytic activity of nanobelts is evaluated by the degradation of Methyl Orange (MO) dye under visible light irradiation. Notably, the nanobelts can completely degrade 100 mL of 15 mg mL(-1) MO in 20 minutes with excellent recycling and structural stability, suggesting their excellent photocatalytic performance. In comparison with a sheet-like sample, the high efficiency of the self-assembled Cu2MoS4 nanobelts is attributed to a high surface area and a unique band gap, agreeing with the nitrogen adsorption analysis and photoluminescence spectra. This study offers a self-assembled synthetic route to create new multifunctional nanoarchitectures composed of atomic layers, and thus may open a window for greatly extending potential applications in water pollution treatment, photocatalytic water-splitting, solar cells and other related fields.

  8. Hydrothermal fabrication and visible-light-driven photocatalytic properties of bismuth vanadate with multiple morphologies and/or porous structures for methyl orange degradation.

    Science.gov (United States)

    Jiang, Haiyan; Dai, Hongxing; Meng, Xue; Zhang, Lei; Deng, Jiguang; Liu, Yuxi; Au, Chak Tong

    2012-01-01

    Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100 degrees C with poly(vinyl pyrrolidone) (PVP) and urea (pH = 2) and at 160 degrees C with NaHCO3 (pH = 7 and 8), respectively. The PVP-derived BiVO4 showed much higher surface areas (5.0-8.4 m2/g) and narrower bandgap energies (2.45-2.49 eV). The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.

  9. Structural, optical and photocatalytic properties of visible light driven zinc oxide hybridized two-dimensional π-conjugated polymeric g-C3N4 composite

    Science.gov (United States)

    Murugesan, Pramila; Girichandran, Nandalal; Narayanan, Sheeba; Manickam, Matheswaran

    2018-01-01

    Zinc oxide (ZnO) hybridized with graphitic carbon nitride (g-C3N4) composite was prepared via one step calcination method and well characterized using various physiochemical techniques. The prepared composite exhibits excellent photocatalytic activity and stability for decolorization of methylene blue (MB) dye solution under visible light irradiation. Effect of various rate determining parameters such as catalyst loading, initial dye concentration and pH on the decolorization of MB has been analyzed. The optimum conditions for efficient color removal were found to be 7, 10 ppm and 2 g/L for pH, dye concentration and catalyst dosage respectively. The intermediate compounds formed during the decolorization process were evaluated by GCMS spectra. It was inferred that the ZnO/g-C3N4 (98.83%) composite exhibits highest decolorization efficiency as compare with pure g-C3N4 (35.21%). Such enhancement of photocataytic activity is mainly attributed to the efficient separation of photo induced electron hole pairs via Z-scheme model composed of ZnO and g-C3N4.

  10. Hierarchical core-shell SiO2@PDA@BiOBr microspheres with enhanced visible-light-driven photocatalytic performance.

    Science.gov (United States)

    Zhu, Shuai-Ru; Qi, Qi; Zhao, Wen-Na; Wu, Meng-Ke; Fang, Yuan; Tao, Kai; Yi, Fei-Yan; Han, Lei

    2017-08-29

    To explore catalysts combining highly accessible specific surface areas with low recombination of the photo-induced electron-hole pairs, a novel SiO2@PDA@BiOBr composite photocatalyst with a hierarchical core-shell structure was prepared by a facile solvothermal method. The catalyst shows a superior performance on photodegradation of Rhodamine B under visible light irradiation, especially for SiO2@PDA-2@BiOBr with the reactant kinetics constant (k = 0.0487 min-1). The enhanced photocatalytic performance of SiO2@PDA-2@BiOBr was ascribed to the decreased band-gap, higher surface area, and effectively photo-generated electron-hole pairs by the introduction of polydopamine (PDA). In addition, the photocatalytic degradation is initiated by ˙O2- derived from dye photosensitization and h+ from the BiOBr. Cyclic experiments also indicate that the SiO2@PDA-2@BiOBr is reusable during the photodegradation process. The hierarchical core-shell SiO2@PDA@BiOBr photocatalyst will provide a theoretical model for the development of physical chemistry and structural properties of BiOBr-based composites to enhance the photocatalytic performances.

  11. Facile fabrication of mesoporous Fe-Ti-SBA15 silica with enhanced visible-light-driven simultaneous photocatalytic degradation and reduction reactions

    Science.gov (United States)

    Chang, Fei; Jiao, Mingzhi; Xu, Quan; Deng, Baoqing; Hu, Xuefeng

    2018-03-01

    A series of mesoporous iron-titanium-containing silica Fe-TiO2-SBA15 (FTS) were constructed via a facile one-pot hydrothermal route and subsequently characterized by X-ray diffraction patterns, UV-vis diffuse reflection spectroscopy, transmission electron microscopy, scanning electron microscopy, nitrogen adsorption-desorption, X-ray photoelectron spectroscopy, and X-ray energy dispersion spectroscopy. By analyses, these samples possessed ordered two-dimensional hexagonal mesoporous structures, mainly involving mixed dual-phases of anatase and rutile TiO2, like commercial titania P25. The UV-vis diffuse reflection spectra demonstrated the presence of Fe species that was further confirmed by the X-ray photoelectron spectra and X-ray energy dispersion spectrum. The existence of Fe species in form of Fe3+ cations played an important role on the phase composition and electronic structure of these samples. With structural and morphological merits, these samples exhibited relatively high photocatalytic efficiency toward the degradation of dye methylene blue (MB) and reduction of Cr(VI) under visible-light irradiation, comparing with P25. In addition, among all candidates, the sample with a Fe/Si molar ratio of 0.03 showed the highest catalytic performance under optimal conditions, especially in the coexistence of both MB and Cr(VI), revealing an obviously synergistic effect when the consumption of both contaminants occurred. Finally, a primary catalytic mechanism was speculated on basis of active species capture experiments.

  12. CeO2/Bi2WO6Heterostructured Microsphere with Excellent Visible-light-driven Photocatalytic Performance for Degradation of Tetracycline Hydrochloride.

    Science.gov (United States)

    Zhang, Fengjun; Zou, Shuang; Wang, Tianye; Shi, Yuxi; Liu, Peng

    2017-10-01

    CeO 2 /Bi 2 WO 6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO 2 /Bi 2 WO 6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi 2 WO 6 in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible-light irradiation. The 1CeO 2 /2Bi 2 WO 6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO 2 and Bi 2 WO 6 in the as-prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO 2 could significantly enhance the photocatalytic activity of CeO 2 /Bi 2 WO 6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO 2 /Bi 2 WO 6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory. © 2017 The American Society of Photobiology.

  13. Mechanistic investigation of visible light driven photocatalytic inactivation of E. coli by Ag-AgCl/ZnFe2O4.

    Science.gov (United States)

    Upreti, Akhanda Raj; Khadgi, Nirina; Li, Yi

    2018-01-17

    In this study, photocatalytic inactivation of Escherichia coli was investigated over magnetic nanocomposite Ag-AgCl/ZnFe 2 O 4 . The nanocomposite demonstrated efficient photocatalytic activity by complete inactivation of the bacteria within 60 min of visible light irradiation. The anions HPO 4 2- and SO 4 2- were found to play the most important role in the inhibition of photocatalytic inactivation of E. coli. A systematic investigation of mechanism of photocatalytic bacterial inactivation was carried out based on cell membrane injury test, scanning electron microscopy (SEM) of bacterial morphology changes, Fourier transform infrared (FTIR) spectroscopy of E. coli cells before and after treatment, superoxide dismutase (SOD) and catalase (CAT) activity assay, and role of various reactive oxygen species (ROS). The activities of SOD and CAT enzymes were found to decrease due to the ROSs attacks during photocatalytic inactivation. The ROS produced in the photocatalytic disinfection severely altered the bacterial permeability and led to protein fragmentation, release of ions, and generation of protein carbonyl derivatives. The leaked cytoplasmic substances and cell debris were further degraded and, ultimately, mineralized with prolonged photocatalytic treatment.

  14. Carbon vacancy-induced enhancement of the visible light-driven photocatalytic oxidation of NO over g-C3N4 nanosheets

    Science.gov (United States)

    Li, Yuhan; Ho, Wingkei; Lv, Kangle; Zhu, Bicheng; Lee, Shun Cheng

    2018-02-01

    g-C3N4 (gCN) with carbon vacancy has been extensively investigated and applied in (photo)catalysis. Engineering the carbon vacancy in gCN is of great importance, but it remains a challenging task. In this work, we report for the first time the fabrication of gCN with carbon vacancy (Cv-gCN) via thermal treatment of pristine gCN in CO2 atmosphere. The photocatalytic performance of Cv-gCN is evaluated on the basis of NO oxidization under visible light irradiation (λ > 400 nm) in a continual reactor. The successful formation of carbon vacancy in gCN is confirmed through electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). The photocatalytic oxidation removal rate of NO over Cv-gCN is 59.0%, which is two times higher than that over pristine gCN (24.2%). The results of the quenching experiment show that superoxide radicals (O2rad -) act as the main reactive oxygen species, which is responsible for the oxidation of NO. The enlarged BET surface areas and negatively shifted conduction band (CB) potential enhance the photocatalytic activity of Cv-gCN, which facilitates the efficient electron transfer from the CB of Cv-gCN to the surface adsorbed oxygen, resulting in the formation of O2rad - that can oxidize NO.

  15. Facile formation of Ag{sub 2}WO{sub 4}/AgX (X = Cl, Br, I) hybrid nanorods with enhanced visible-light-driven photoelectrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jingjing; Yu, Caiyun [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Zheng, Changcheng [Mathematics and Physics Centre, Xi’an Jiaotong-Liverpool University, Suzhou 215123 (China); Etogo, Atangana; Xie, Yunlong; Zhong, Yijun [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Hu, Yong, E-mail: yonghu@zjnu.edu.cn [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China)

    2015-01-15

    Highlights: • Ag{sub 2}WO{sub 4}/AgX hybrid nanorods were prepared by a facile in-situ anion exchange reaction. • Ag{sub 2}WO{sub 4} nanorods and different X{sup −} ions were reacted in water at room temperature. • The hybrids possess significantly enhanced photoelectrochemical properties. • Ag{sub 2}WO{sub 4}/AgBr hybrids exhibit the highest photocatalytic activity among three samples. • The active species tests were also investigated to confirm photocatalytic mechanism. - Abstract: In this work, we demonstrated a general strategy for the preparation of a series of uniform Ag{sub 2}WO{sub 4}/AgX (X = Cl, Br, I) hybrid nanorods by a facile in-situ anion exchange reaction occurring at room temperature between pregrown Ag{sub 2}WO{sub 4} nanorods and different X{sup −} ions in water. Compared with Ag{sub 2}WO{sub 4} nanorods, further investigation has revealed that the as-prepared hybrid nanorods possess significantly enhanced photocurrent response and photocatalytic activity in degrading methyl orange (MO) under visible-light irradiation. In particular, the Ag{sub 2}WO{sub 4}/AgBr hybrid nanorods exhibit the highest photocatalytic activity among the three kinds of samples. The active species tests indicate that superoxide anion radicals and photogenerated holes are responsible for the enhanced photocatalytic performance.

  16. Constructing 2D BiOCl/C3N4 layered composite with large contact surface for visible-light-driven photocatalytic degradation

    Science.gov (United States)

    Liu, Wenwen; Qiao, Lulu; Zhu, Anquan; Liu, Yi; Pan, Jun

    2017-12-01

    The design and construction of a two-dimensional (2D) layered composite with large contact surface provide an efficient way for solving detrimental photoinduced carriers recombination. In this work, 2D layered composite coupling (001) facet of BiOCl nanoplates and (002) facet of C3N4 nanosheets was reasonable designed and successful constructed. In comparison with pure C3N4, the BiOCl/C3N4 hybrid structure with loading of 70% BiOCl exhibits the highest methyl orange photodegradation performance although BiOCl/C3N4 hybrid photocatalyst harvest less visible light. Obviously, enhanced photocatalytic performance is mainly ascribed to large contact surface of 2D layered hybrid structure, which is favorable for the interface electrons transfer and the separation of carriers between C3N4 and BiOCl. A probable degradation mechanism based on trapping experiments of active species, transient photocurrents, photoluminescence spectra, electrochemical impedance spectroscopy and energy band structures is proposed. This work may provide a further insight into the rational construction composites with large interface contact for high-efficiency light utilization.

  17. Highly dispersed palladium nanoparticles anchored on UiO-66(NH2) metal-organic framework as a reusable and dual functional visible-light-driven photocatalyst

    Science.gov (United States)

    Shen, Lijuan; Wu, Weiming; Liang, Ruowen; Lin, Rui; Wu, Ling

    2013-09-01

    Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed Pd nanoparticles of about 3-6 nm in diameter are immobilized in the metal-organic framework (MOF) UiO-66(NH2) via a facile one-pot hydrothermal method. The resulting Pd@UiO-66(NH2) nanocomposite exhibits an excellent reusable and higher visible light photocatalytic activity for reducing Cr(vi) compared with UiO-66(NH2) owing to the high dispersion of Pd nanoparticles and their close contact with the matrix, which lead to the enhanced light harvesting and more efficient separation of photogenerated electron-hole pairs. More significantly, the Pd@UiO-66(NH2) could be used for simultaneous photocatalytic degradation of organic pollutants, like methyl orange (MO) and methylene blue (MB), and reduction of Cr(vi) with even further enhanced activity in the binary system, which could be attributed to the synergetic effect between photocatalytic oxidation and reduction by individually consuming photogenerated holes and electrons. This work represents the first example of using the MOFs-based materials as dual functional photocatalyst to remove different categories of pollutants simultaneously. Our finding not only proves great potential for the design and application of MOFs-based materials but also might bring light to new opportunities in the development of new high-performance photocatalysts.Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed Pd nanoparticles of about 3-6 nm in diameter are immobilized in the metal-organic framework (MOF) UiO-66(NH2) via a facile one-pot hydrothermal method. The resulting Pd@UiO-66(NH2) nanocomposite exhibits an excellent reusable and higher visible light photocatalytic activity for reducing Cr(vi) compared with UiO-66(NH2) owing to the

  18. Visible-light driven Photoelectrochemical Immunosensor Based on SnS2@mpg-C3N4 for Detection of Prostate Specific Antigen.

    Science.gov (United States)

    Zhang, Yifeng; Liu, Yixin; Li, Rongxia; Saddam Khan, Malik; Gao, Picheng; Zhang, Yong; Wei, Qin

    2017-07-05

    Herein, a novel label-free photoelectrochemical (PEC) immunosensor based on SnS2@mpg-C3N4 nanocomposite is fabricated for the detection of prostate specific antigen (PSA) in human serum. Firstly, mesoporous graphite-like carbon nitride (mpg-C3N4) with carboxyl groups is synthesized successfully which possesses high specific surface area and large pore volume. Then, SnS2 as a typical n-type semiconductor with weak photoelectric conversion capability is successfully loaded on carboxylated mpg-C3N4 to form a well-matched overlapping band-structure. The as-synthesized SnS2@mpg-C3N4 nanocomposite performs outstanding photocurrent response under visible-light irradiation due to low recombination rate of photoexcited electron-hole pairs, which is transcend than pure SnS2 or pure mpg-C3N4. It is worth noting that SnS2@mpg-C3N4 nanocomposite is firstly employed as the photoactive material in PEC immunosensor area. The concentration of PSA can be analyzed by the decrease in photocurrent resulted from increased steric hindrance of the immunocomplex. Under the optimal conditions, the developed PEC immunosensor displays a liner photocurrent response in the range of 50 fg·mL-1 ~ 10 ng·mL-1 with a low detection limit of 21 fg·mL-1. Furthermore, the fabricated immunosensor with satisfactory stability, reproducibility and selectivity provides a novel method for PSA determination in real sample analysis.

  19. Visible-light-driven N-(BiO)2CO3/Graphene oxide composites with improved photocatalytic activity and selectivity for NOx removal

    Science.gov (United States)

    Chen, Meijuan; Huang, Yu; Yao, Jie; Cao, Jun-ji; Liu, Yuan

    2018-02-01

    N-doped (BiO)2CO3 (NBOC)/graphene oxide (GO) composite obtained from three-dimensional hierarchical microspheres is successfully synthesized by one-pot hydrothermal method for the first time. In this synthesis, citrate ion plays a critical role in N doping. The obtained samples are used to degrade gaseous nitrogen oxides (NOx) at parts-per-billion (ppb) level under visible-light irradiation. NBOC-GO composite with 1.0 wt% graphene oxide (GO) displays the highest photocatalytic NO removal efficiency, which is 4.3 times higher than that of pristine (BiO)2CO3. Moreover, NBOC-GO composite significantly inhibits toxic NO2 intermediate production, indicating its high selectivity for NO conversion. Compared with regular GO, N doping considerably improves the catalytic performance of NBOC-GO composite, which increases NO removal by 74.6% and fully inhibits NO2 generation. The improved photocatalytic activity is mainly ascribed to extended optical absorption ability and enhanced separation efficiency of photogenerated charge carriers over NBOC-GO composite. Both results of electron spin resonance and theoretical analysis of band structure indicate that NO removal is dominated by oxidation with rad OH and rad O2- radicals. The photocatalytic activity improvement mechanism over the NBOC-GO composite is proposed accordingly based on systematic characterizations. This study demonstrates a feasible route to fabricating Bi-containing composites with high selectivity and stability for air pollution control and provides a new insight into the associated photocatalytic mechanisms.

  20. Visible light-driven photocatalytic degradation of the organic pollutant methylene blue with hybrid palladium–fluorine-doped titanium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lázaro-Navas, Sonia; Prashar, Sanjiv; Fajardo, Mariano; Gómez-Ruiz, Santiago, E-mail: santiago.gomez@urjc.es [Universidad Rey Juan Carlos, Departamento de Biología y Geología, Física y Química Inorgánica, ESCET (Spain)

    2015-02-15

    The synthesis of mesoporous aggregates of titanium oxide nanoparticles (F0) is described using a very cheap and simple synthetic protocol. This consists of the reaction of titanium tetraisopropoxide and a solution of HNO{sub 3} in water (pH 2.0) and subsequent filtration. In addition, fluorine-doped titanium oxides (F1, F2, F5 and F10) were synthesized using the same method, adding increasing amounts of NaF to the reaction mixture (avoiding the use of expensive reagents such as NH{sub 4}F or trifluoroacetic acid). The resulting materials were calcined at different temperatures (500, 600 and 650 °C) giving particles sized between 10 and 20 nm. Furthermore, a hybrid F-doped TiO{sub 2} with supported palladium nanoparticles of ca. 20 nm (F5-500-Pd1) was synthesized by grafting an organometallic palladium(II) salt namely [Pd(cod)Cl{sub 2}] (cod = 1,5-cyclooctadiene). Photocatalytic studies of the degradation of methylene blue (MB) were carried out under UV light using all the synthesized material (non-doped an F-doped TiO{sub 2}), observing that the increase in the quantity of fluorine has a positive effect on the photocatalytic activity. F5-500 is apparently the material which has the most convenient structural properties (in terms of surface area and anatase/rutile ratio) and thus a higher photocatalytic activity. The hybrid material F-doped TiO{sub 2}–Pd nanoparticles (F5-500-Pd1) has a lower band gap value than F5-500, and thus photocatalytic degradation of MB under LED visible light was achieved using F5-500-Pd1 as photocatalyst.

  1. Two-dimensional TiO{sub 2}-based nanosheets co-modified by surface-enriched carbon dots and Gd{sub 2}O{sub 3} nanoparticles for efficient visible-light-driven photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Dingze, E-mail: 1005116870@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Fang, Pengfei, E-mail: fangpf@whu.edu.cn [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Ding, Junqian, E-mail: 630736958@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Yang, Minchen, E-mail: 1023635028@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Cao, Yufei, E-mail: 344541464@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Zhou, Yawei, E-mail: 769107311@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Peng, Kui, E-mail: 758007737@qq.com [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Kondamareddy, Kiran Kumar, E-mail: kokila_kkk@yahoo.co.in [Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Liu, Min, E-mail: liumhb@126.com [State Grid Zhejiang Electric Power Research Institute, Hangzhou, Zhejiang 310007 (China)

    2017-02-28

    Highlights: • Gd-C-TNSs with high stability and recycle usability were prepared by two-pot method. • Gd{sub 2}O{sub 3} loading results in the structure changes of TNSs and increase of the Ti{sup 3+} ions. • Modified CDs leads to obvious increase of optical absorption ability and red shift. • Appropriate amount of Gd{sub 2}O{sub 3} nanoparticles and CDs improve the separation of charges. • Gd-C-TNSs exhibit excellent synergistic photocatalytic activity for Cr(VI) and RhB. - Abstract: Two-dimensional TiO{sub 2}-based nanosheets (TNSs) co-modified by surface-enriched carbon dots (CDs) and Gd{sub 2}O{sub 3} nanoparticles: (Gd-C-TNSs), capable of exhibiting visible-light-driven photo catalysis were synthesized using a two-pot hydrothermal route. The samples had a sheet-like structure, thickness of approximately 3.6 nm, large specific surface area of 240–350 cm{sup 2}/g. The CDs (2–3 nm) and Gd{sub 2}O{sub 3} nanoparticles (1–2 nm) were highly dispersed over the surface of the nanosheets. The co-modification by Gd{sub 2}O{sub 3} nanoparticles and CDs influenced the crystallinity, crystal structure, and surface area of the TNSs, and improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be improved by an appropriate amount of modification. A very high efficiency was obtained using 0.5 at% Gd/Ti and 3.0 g/L of CDs. The visible-light-induced photocatalytic activity is enhanced under the isolated Cr(VI) system, isolated Rhodamin B (RhB) system, and the synergism between RhB degradation and Cr(VI) reduction for the Gd-C-TNSs photocatalysts. Initially, the photocatalytic activity gradually increased with an increase in the amount of CDs, and then decreased after attaining a maximum, in the case where 0.5 at% Gd/Ti and 3.0 g/L of CDs were used. The enhancement in the photocatalytic activity was attributed to the synergetic effect of the Gd{sub 2}O

  2. Three-Dimensional Zn0.5Cd0.5S/Reduced Graphene Oxide Hybrid Aerogel: Facile Synthesis and the Visible-Light-Driven Photocatalytic Property for Reduction of Cr(VI in Water

    Directory of Open Access Journals (Sweden)

    Wei Xiao

    2016-01-01

    Full Text Available A series of three-dimensional ZnxCd1-xS/reduced graphene oxide (ZnxCd1-xS/RGO hybrid aerogels was successfully synthesized based on a one-pot hydrothermal approach, which were subsequently used as visible-light-driven photocatalysts for photoreduction of Cr(VI in water. Over 95% of Cr(VI was photoreduced by Zn0.5Cd0.5S/RGO aerogel material within 140 min, and such photocatalytic performance was superior to that of other ZnxCd1-xS/RGO aerogel materials (x≠0.5 and bare Zn0.5Cd0.5S. It was assumed that the enhanced photocatalytic activity of Zn0.5Cd0.5S/RGO aerogel was attributed to its high specific surface area and the preferable synergetic catalytic effect between Zn0.5Cd0.5S and RGO. Besides, Zn0.5Cd0.5S/RGO aerogel materials were robust and durable enough so that they could be reused several times with merely limited loss of photocatalytic activity. The chemical composition, phase, structure, and morphology of Zn0.5Cd0.5S/RGO aerogel material were carefully examined by a number of techniques like XRD, SEM, TEM, BET, Raman characterizations, and so on. It was found that Zn0.5Cd0.5S/RGO aerogel possessed hierarchically porous architecture with the specific surface area as high as 260.8 m2 g−1. The Zn0.5Cd0.5S component incorporated in Zn0.5Cd0.5S/RGO aerogel existed in the form of solid solution nanoparticles, which were uniformly distributed in the RGO matrix.

  3. Novel Y doped Bi{sub 2}WO{sub 6} photocatalyst: Hydrothermal fabrication, characterization and enhanced visible-light-driven photocatalytic activity for Rhodamine B degradation and photocurrent generation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Ranran [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Huang, Hongwei, E-mail: hhw@cugb.edu.cn [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Tian, Na [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Zhang, Yihe, E-mail: zyh@cugb.edu.cn [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Guo, Yuxi [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Zhang, Tierui [Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-03-15

    Visible-light-driven (VLD) Yttrium (Y) ion doped Bi{sub 2}WO{sub 6} photocatalyst has been synthesized via a facile hydrothermal route. Incorporation of Y{sup 3} {sup +} into Bi{sub 2}WO{sub 6} lattice was successfully confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ICP analysis. The microstructure and optical property of the as-prepared samples have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption isotherm and UV–vis diffuse reflectance spectra (DRS). The photocatalytic experiments indicated that the Y-Bi{sub 2}WO{sub 6} showed a much higher photocatalytic activity than the pristine Bi{sub 2}WO{sub 6} for the degradation of Rhodamine B (RhB) and photocurrent (PC) generation. This enhancement should be ascribed to the slightly increased band gap and the generated defects by Y{sup 3} {sup +} doping, thus resulting in a much lower recombination rate of the photoinduced electrons and holes. Such a process was verified by the photoluminescence (PL) spectroscopy. In addition, the active species trapping experiments indicated that holes (h{sup +}) and superoxide radicals (·O{sub 2}{sup −}) play important roles in the photocatalytic reaction. - Highlights: • Novel Y-Bi{sub 2}WO{sub 6} photocatalyst has been synthesized by a facile hydrothermal route. • Y-Bi{sub 2}WO{sub 6} exhibits a much higher photocatalytic activity than pristine Bi{sub 2}WO{sub 6}. • Holes (h{sup +}) and superoxide radicals (·O{sub 2}{sup −}) are the two main active species. • Y{sup 3} {sup +} ion can result in a low recombination of photogenerated electron and hole.

  4. Removal of rhodamine 6G dye contaminant by visible light driven immobilized Ca{sub 1−x}Ln{sub x}MnO{sub 3} (Ln = Sm, Ho; 0.1 ≤ x ≤ 0.4) photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Barrocas, B. [Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande C8, 1749-016 Lisboa (Portugal); Sério, S. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Rovisco, A. [Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Nunes, Y. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Jorge, M.E. Melo, E-mail: mdjorge@fc.ul.pt [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande C8, 1749-016 Lisboa (Portugal)

    2016-01-01

    Graphical abstract: - Abstract: Visible-light-driven Ca{sub 1−x}Ln{sub x}MnO{sub 3} (Ln = Sm, Ho; 0.1 ≤ x ≤ 0.4) films were grown by RF-magnetron sputtering onto fused silica substrates. The effects of Ca{sup 2+} substitution for Ho{sup 3+} or Sm{sup 3+} in Ca{sub 1−x}Ln{sub x}MnO{sub 3} on the structural, morphological and photocatalytic properties for rhodamine 6G dye degradation under visible light irradiation were investigated. XRD showed a pure typical perovskite phase for all the prepared films, except for Ca{sub 0.9}Ho{sub 0.1}MnO{sub 3} and a decrease of the crystallite size with the increase of the amount of ion substituted. SEM and AFM revealed that the films surface is dense, with low roughness. UV–vis spectroscopy indicated for the two series band gaps in the range of 1.6–2.8 eV, being lower for the films containing holmium. The results showed that some Ca{sub 1−x}Ho{sub x}MnO{sub 3} and Ca{sub 1−x}Sm{sub x}MnO{sub 3} films present higher photocatalytic activity for Rh6G degradation in comparison with TiO{sub 2} films and for the same x value the Ho-films exhibited higher photocatalytic activity. For both films series the maximal degradation rate was obtained for x = 0.2; above this content the degradation percentage exhibits a decreasing trend with the increase of Ho or Sm substitution, except for x = 0.4 in the case of Ho system, which is observed again an increase in the degradation rate. The Rh6G photocatalytic degradation followed a pseudo first-order reaction kinetics. XRD and SEM of the used photocatalysts evidenced high photochemical stability.

  5. Amine-Functionalized Al-MOF#@yxSm2O3-ZnO: A Visible Light-Driven Nanocomposite with Excellent Photocatalytic Activity for the Photo-Degradation of Amoxicillin.

    Science.gov (United States)

    Abazari, Reza; Mahjoub, Ali Reza

    2018-02-15

    A visible light-driven amine-functionalized Al-based MOF # @ y x Sm 2 O 3 -ZnO nanocomposite (NH 2 -MOF # @ y x Sm 2 O 3 -ZnO NCP) was synthesized as an effective photocatalyst for AMX degradation in the presence of ultrasound, in which # is MOF synthesis conditions from MOF I to MOF XII and x and y stand for the weight percentages of Sm 2 O 3 -to-ZnO and Sm 2 O 3 -ZnO-to-MOF, respectively. The β-lactam antibiotic AMX, which is widely used for treating Gram-positive and Gram-negative bacterial infections in both animals and humans, was employed as a model pollutant. Using different detection techniques, the synthesized materials were characterized. Furthermore, effects of different synthesis methods, ultrasonic time, precursor concentration, sonication amplitude, and modulators on the MOFs photocatalytic behavior were taken into account. Also, catalytic dose and recycling, H 2 O 2 usage, and operating pH effects were investigated. Compared to the pure forms of NH 2 -MOF-53(Al) and Sm 2 O 3 -ZnO, the NCPs having the optimal Sm 2 O 3 -ZnO and NH 2 -MOF-53(Al) contents highly influenced the photocatalytic activity due to the synergetic impacts of the high charge mobility and the red shift in the NH 2 -MOF@Sm 2 O 3 -ZnO NCPs absorption edge compared to the Sm 2 O 3 -ZnO nanoflowers. We used a TOC analyzer, UV/vis spectroscopy, and HPLC chromatogram to estimate the rate of AMX elimination in water over NH 2 -MOF XII @ 30 7 Sm 2 O 3 -ZnO NCPs as our optimal sample. In addition, after the AMX pollutant degradation, the NH 2 -MOF@Sm 2 O 3 -ZnO NCPs were structurally stable and maintained the majority of their photocatalytic properties even after five runs of recycling process The NH 2 -MOF XII @ 30 7 Sm 2 O 3 -ZnO NCPs as the superior photocatalysts were more examined and a mechanism for the AMX degradation was suggested. As a suggestion, our obtained results can be used as a starting point for the preparation of the other heterogeneous MOF-based NCPs combined with the Sm

  6. Photostability and visible-light-driven photoactivity enhancement of hierarchical ZnS nanoparticles: The role of embedment of stable defect sites on the catalyst surface with the assistant of ultrasonic waves.

    Science.gov (United States)

    Mahvelati-Shamsabadi, T; Goharshadi, E K

    2017-01-01

    Zinc sulfide is a UV-active photocatalyst and it undergoes photocorrosion under light irradiation. In this work, the defect sites on ZnS nanoparticles (NPs) surfaces were induced with the help of powerful ultrasonic waves. The defect sites caused (1) suppression of photocorrosion in a large extent under UV light irradiation and (2) enhancement of visible light photo activity. The photocorrosion inhibition was induced by raising valence band (VB) position through the formation of interstitial zinc and sulfur vacancy states in the ZnS band structure and weakening of oxidative capacity of hole. The enhancement of visible light photocatalytic activity may be related to the generation of more defect energy states in the ZnS band gap. Under visible light irradiation, the electron was excited from the ZnS VB to the interstitial sulfur and zinc vacancy states before injecting into the conduction band of ZnS. Therefore, we modified the band gap of ZnS so that it acts as a visible light active photocatalyst. ZnS NPs were prepared using two different classical and ultrasound methods. The prepared ZnS using ultrasound method, exhibited more outstanding photocatalytic activity for degrading reactive black 5 (RB5) under UV and sunlight irradiation in comparison with the classical method. Details of the degradation mechanism under UV light were investigated. This work provides new insights to understanding the photocorrosion stability and visible light activity of bare ZnS photocatalyst. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Highly efficient visible-light driven photocatalytic hydrogen production from a novel Z-scheme Er3+:YAlO3/Ta2O5-V5+||Fe3+-TiO2/Au coated composite

    Science.gov (United States)

    Wang, Guowei; Ma, Xue; Wei, Shengnan; Li, Siyi; Qiao, Jing; Wang, Jun; Song, Youtao

    2018-01-01

    In this work, the preparation of a novel Z-scheme photocatalyst, Er3+:YAlO3/Ta2O5-V5+||Fe3+-TiO2/Au coated composite, for visible-light photocatalytic hydrogen production is reported for the first time. In this photocatalyst, Au nanoparticles as conduction band co-catalyst provide more active sites to enrich electrons. Ta2O5-V5+||Fe3+-TiO2 as composite redox cycle system thoroughly separates the photo-generated electrons and holes. In addition, Er3+:YAlO3 as up-conversion luminescence agent (from visible-light to ultraviolet-light) provides enough ultraviolet-light for satisfying the energy demand of wide band-gap semiconductors (TiO2 and Ta2O5). The photocatalytic hydrogen production can be achieved from methanol as sacrificial agent (electron donor) under visible-light irradiation. The main influence factors such as initial solution pH and molar ratio of TiO2 and Ta2O5 on visible-light photocatalytic hydrogen production activity of Er3+:YAlO3/Ta2O5-V5+||Fe3+-TiO2/Au coated composite are discussed in detail. The results show that the Er3+:YAlO3/Ta2O5-V5+||Fe3+-TiO2/Au coated composite with 1.0:0.5 M ratio of TiO2 and Ta2O5 in methanol aqueous solution at pH = 6.50 displays the highest photocatalytic hydrogen production activity. Furthermore, a high level of photocatalytic activity can be still maintained within three cycles under the same conditions. It implies that the prepared Z-scheme Er3+:YAlO3/Ta2O5-V5+||Fe3+-TiO2/Au coated composite may be a promising photocatalyst utilizing solar energy for hydrogen production.

  8. Ternary ZnO/AgI/Ag{sub 2}CO{sub 3} nanocomposites: Novel visible-light-driven photocatalysts with excellent activity in degradation of different water pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Golzad-Nonakaran, Behrouz; Habibi-Yangjeh, Aziz, E-mail: ahabibi@uma.ac.ir

    2016-12-01

    ZnO/AgI/Ag{sub 2}CO{sub 3} nanocomposites with different Ag{sub 2}CO{sub 3} contents were fabricated by a facile ultrasonic-irradiation method. The resultant samples were fairly characterized using XRD, EDX, SEM, TEM, UV–vis DRS, FT-IR, and PL techniques to reveal their microstructure, purity, morphology, and spectroscopic properties. Photocatalytic activity of the prepared samples was investigated by photodegradation of four dye pollutants (rhodamine B, methyl orange, methylene blue, and fuchsine) under visible-light irradiation. The photocatalytic experiments in degradation of rhodamine B showed that the ternary ZnO/AgI/Ag{sub 2}CO{sub 3} (30%) nanocomposite has an enhanced activity nearly 19 and 14 times higher than those of the binary ZnO/Ag{sub 2}CO{sub 3} and ZnO/AgI photocatalysts, respectively. Based on the obtained results, the highly enhanced activity was attributed to generation of more electron-hole pairs under visible-light irradiation and separation of the photogenerated charge carriers due to formation of tandem n-n heterojunctions between counterparts of the nanocomposite. The active species trapping experiments were also examined and it was showed that superoxide ion radicals play a vital role in the photocatalytic degradation reaction. More importantly, the ternary photocatalyst demonstrated good photostability. - Highlights: • ZnO/AgI/Ag{sub 2}CO{sub 3} nanocomposites were fabricated by an ultrasonic-irradiation method. • The activity was investigated by photodegradation of four dyes under visible light. • ZnO/AgI/Ag{sub 2}CO{sub 3} (30%) nanocomposite has the best activity under visible light. • Activity is 19 and 14-folds higher than ZnO/Ag{sub 2}CO{sub 3} and ZnO/AgI in degradation of RhB.

  9. Light-driven robotics for nanoscopy

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    2013-01-01

    The science fiction inspired shrinking of macro-scale robotic manipulation and handling down to the micro- and nanoscale regime opens new doors for exploiting the forces and torques of light for micro- and nanoscopic probing, actuation and control. Advancing light-driven micro-robotics requires...... and matter for robotically probing at the smallest biological length scales....

  10. One pot hydrothermal synthesis of a novel BiIO{sub 4}/Bi{sub 2}MoO{sub 6} heterojunction photocatalyst with enhanced visible-light-driven photocatalytic activity for rhodamine B degradation and photocurrent generation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hongwei, E-mail: hhw@cugb.edu.cn; Liu, Liyuan; Zhang, Yihe, E-mail: zyh@cugb.edu.cn; Tian, Na

    2015-01-15

    Graphical abstract: The efficient charge transfer occurred at the interface of BiIO{sub 4}/Bi{sub 2}MoO{sub 6} heterojunction results in the efficient separation of photoexcited electron–hole pairs and promotes the photocatalytic activity. - Highlights: • BiIO{sub 4}/Bi{sub 2}MoO{sub 6} composites were synthesized by a one-step hydrothermal method. • The BiIO{sub 4}/Bi{sub 2}MoO{sub 6} composite exhibits much better photoelectrochemical performance. • The highly improved photocatalytic activity is attributed to heterojunction structure. • Holes (h{sup +}) are the main active species in the photodegradation process of RhB. - Abstract: A novel BiIO{sub 4}/Bi{sub 2}MoO{sub 6} heterojunction photocatalyst has been successfully developed by a one-step hydrothermal method for the first time. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflection spectroscopy (DRS). Compared to pure BiIO{sub 4} and Bi{sub 2}MoO{sub 6}, the BiIO{sub 4}/Bi{sub 2}MoO{sub 6} composite exhibits the much better photoelectrochemical performance for Rhodamine B (RhB) degradation and photocurrent (PC) generation under visible light irradiation (λ > 420 nm). This enhancement on visible-light-responsive photocatalytic activity should be attributed to the fabrication of a BiIO{sub 4}/Bi{sub 2}MoO{sub 6} heterojunction, thus resulting in the high separation and transfer efficiency of photogenerated charge carriers. The supposed photocatalytic mechanism dominated by holes (h{sup +}) was verified by the photoluminescence (PL) spectroscopy, electrochemical impedance spectra (EIS) and active species trapping experiments.

  11. Light-driven cytochrome P450 hydroxylations

    DEFF Research Database (Denmark)

    Jensen, Kenneth; Jensen, Poul Erik; Møller, Birger Lindberg

    2011-01-01

    Plants are light-driven "green" factories able to synthesize more than 200,000 different bioactive natural products, many of which are high-value products used as drugs (e.g., artemisinin, taxol, and thapsigargin). In the formation of natural products, cytochrome P450 (P450) monooxygenases play...... a key role in catalyzing regio- and stereospecific hydroxylations that are often difficult to achieve using the approaches of chemical synthesis. P450-catalyzed monooxygenations are dependent on electron donation typically from NADPH catalyzed by NADPH-cytochrome P450 oxidoreductase (CPR......). The consumption of the costly cofactor NADPH constitutes an economical obstacle for biotechnological in vitro applications of P450s. This bottleneck has been overcome by the design of an in vitro system able to carry out light-driven P450 hydroxylations using photosystem I (PSI) for light harvesting...

  12. Carbon nitride–TiO2 hybrid modified with hydrogenase for visible light driven hydrogen production† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc02017d Click here for additional data file.

    Science.gov (United States)

    Caputo, Christine A.; Wang, Lidong; Beranek, Radim

    2015-01-01

    A system consisting of a [NiFeSe]–hydrogenase (H2ase) grafted on the surface of a TiO2 nanoparticle modified with polyheptazine carbon nitride polymer, melon (CNx) is reported. This semi-biological assembly shows a turnover number (TON) of more than 5.8 × 105 mol H2 (mol H2ase)–1 after 72 h in a sacrificial electron donor solution at pH 6 during solar AM 1.5 G irradiation. An external quantum efficiency up to 4.8% for photon-to-hydrogen conversion was achieved under irradiation with monochromatic light. The CNx–TiO2–H2ase construct was also active under UV-free solar light irradiation (λ > 420 nm), where it showed a substantially higher activity than TiO2–H2ase and CNx–H2ase due, in part, to the formation of a CNx–TiO2 charge transfer complex and highly productive electron transfer to the H2ase. The CNx–TiO2–H2ase system sets a new benchmark for photocatalytic H2 production with a H2ase immobilised on a noble- and toxic-metal free light absorber in terms of visible light utilisation and stability. PMID:28757952

  13. Evidence of superoxide radical contribution to demineralization of sulfamethoxazole by visible-light-driven Bi2O3/Bi2O2CO3/Sr6Bi2O9 photocatalyst.

    Science.gov (United States)

    Ding, Shiyuan; Niu, Junfeng; Bao, Yueping; Hu, Lijuan

    2013-11-15

    Photocatalytic degradation of sulfamethoxazole (SMX) was investigated using Bi2O3/Bi2O2CO3/Sr6Bi2O9 (BSO) photocatalyst under visible light (>420 nm) irradiation. The photochemical degradation of SMX followed pseudo-first-order kinetics. The reaction kinetics was determined as a function of initial SMX concentrations (5-20 mg L(-1)), initial pH (3-11) and BSO concentrations (6-600 mg L(-1)). Approximately, 90% of SMX (10 mg L(-1)) degradation and 36% of TOC reduction were achieved at pH 7.0 after 120 min irradiation. The main mineralization products, including NH4(+), NO3(-), SO4(2-) and CO2, as well as intermediates 3-amino-5-methylisoxazole (AMI), p-benzoquinone (BZQ), and sulfanilic acid (SNA) were detected in aqueous solution. The formation of O2(*-) radical was evidenced by using electron spin resonance and a chemiluminescent probe, luminal. A possible degradation mechanism involving excitation of BSO, followed by charge injection into the BSO conduction band and formation of reactive superoxide radical (O2(*-)) was proposed for the mineralization of SMX. During the reaction, the O2(*-) radical attacks the sulfone moiety and causes the cleavage of the SN bond, which leads to the formation of two sub-structure analogs, AMI and SNA. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Preparation of 2D square-like Bi2S3-BiOCl heterostructures with enhanced visible light-driven photocatalytic performance for dye pollutant degradation

    Directory of Open Access Journals (Sweden)

    Jing-jing Xu

    2017-10-01

    Full Text Available A series of Bi2S3-BiOCl composites with two-dimensional (2D square-like structures were prepared via a two-step anion exchange route. X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and diffuse reflectance spectra (DRS were used to investigate the properties of the as-prepared Bi2S3-BiOCl heterostructures. The coupling of BiOCl and Bi2S3 induced enhanced photoabsorption efficiency and bandgap narrowing. A reactive brilliant red X-3B dye was used as a contaminant to test the photocatalytic activity of the obtained Bi2S3-BiOCl samples under visible light irradiation. The sample Bi2S3-BiOCl with a mass ratio of 8:4 exhibited the highest photodegradation efficiency, which was six times higher than that of pure BiOCl. In addition, a mechanism for the enhancement of photocatalytic activity is proposed.

  15. Controllable one-pot synthesis of various one-dimensional Bi{sub 2}S{sub 3} nanostructures and their enhanced visible-light-driven photocatalytic reduction of Cr(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Enlai; Gao, Xuehui; Etogo, Atangana; Xie, Yunlong [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China); Zhong, Yijun, E-mail: yjzhong@zjnu.cn [College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004 (China); Hu, Yong, E-mail: yonghu@zjnu.edu.cn [Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004 (China)

    2014-10-25

    Highlights: • 1D Bi{sub 2}S{sub 3} nanostructures were prepared by a facile ethanol-assisted one-pot reaction. • The size and morphology of the products can be conveniently varied. • The sulfur source plays a crucial role in determining the morphologies of products. • 1D Bi{sub 2}S{sub 3} nanostructures exhibit enhanced photocatalytic reduction of Cr(VI). • Bi{sub 2}S{sub 3} nanowires exhibit the highest photoreduction activity among three samples. - Abstract: One-dimensional (1D) Bi{sub 2}S{sub 3} nanostructures with various morphologies, including nanowires, nanorods, and nanotubes, have been successfully synthesized through a facile ethanol-assisted one-pot reaction. It is found that the size, morphology and structure of the products can be conveniently varied or controlled by simply adjusting the volume ratio of ethanol and water in the reaction system. Further experimental results indicate that sulfur source also plays the other crucial role in determining the product morphology. The synthetic strategy developed in this work is highly efficient in producing 1D Bi{sub 2}S{sub 3} nanostructures with high quality and large quantity. Photocatalysis experiments show the as-prepared 1D Bi{sub 2}S{sub 3} nanostructures possess significantly enhanced photocatalytic reduction of Cr(VI) when exposed to visible light irradiation. Especially, Bi{sub 2}S{sub 3} nanowires exhibit the highest photocatalytic activity and can be used repeatedly after washed with dilute HCl.

  16. Oil-in-Water Self-Assembled Synthesis of Ag@AgCl Nano-Particles on Flower-like Bi2O2CO3 with Enhanced Visible-Light-Driven Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Shuanglong Lin

    2016-06-01

    Full Text Available In this work, a series of novel flower-like Ag@AgCl/Bi2O2CO3 were prepared by simple and feasible oil-in-water self-assembly processes. The phase structures of as-prepared samples were examined by X-ray diffraction (XRD, Scanning electron microscopy (SEM, Transmission electron microscopy (TEM, UV-vis diffuse reflectance spectroscopy (DRS, X-ray fluorescence spectrometer (XRF, etc. The characterization results indicated that the presence of Ag@AgCl did not affect the crystal structure, but exerted a great influence on the photocatalytic activity of Bi2O2CO3 and enhanced the absorption band of pure Bi2O2CO3. The photocatalytic activities of the Ag@AgCl/Bi2O2CO3 samples were determined by photocatalytic degradation of methylene blue (MB under visible light irradiation. The Ag@AgCl (10 wt %/Bi2O2CO3 composite showed the highest photocatalytic activity, degrading 97.9% MB after irradiation for 20 min, which is over 1.64 and 3.66 times faster than that of pure Ag@AgCl (calculated based on the equivalent Ag@AgCl content in Ag@AgCl (10 wt %/Bi2O2CO3 and pure Bi2O2CO3, respectively. Bisphenol A (BPA was also degraded to further prove the degradation ability of Ag@AgCl/Bi2O2CO3. Photocurrent studies indicated that the recombination of photo-generated electron–hole pairs was decreased effectively due to the formation of heterojunctions between flower-like Bi2O2CO3 and Ag@AgCl nanoparticles. Trapping experiments indicated that O2−, h+ and Cl° acted as the main reactive species for MB degradation in the present photocatalytic system. Furthermore, the cycling experiments revealed the good stability of Ag@AgCl/Bi2O2CO3 composites. Based on the above, a photocatalytic mechanism for the degradation of organic compounds over Ag@AgCl/Bi2O2CO3 was proposed.

  17. Oil-in-Water Self-Assembled Synthesis of Ag@AgCl Nano-Particles on Flower-like Bi2O2CO3 with Enhanced Visible-Light-Driven Photocatalytic Activity

    Science.gov (United States)

    Lin, Shuanglong; Liu, Li; Liang, Yinghua; Cui, Wenquan; Zhang, Zisheng

    2016-01-01

    In this work, a series of novel flower-like Ag@AgCl/Bi2O2CO3 were prepared by simple and feasible oil-in-water self-assembly processes. The phase structures of as-prepared samples were examined by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), X-ray fluorescence spectrometer (XRF), etc. The characterization results indicated that the presence of Ag@AgCl did not affect the crystal structure, but exerted a great influence on the photocatalytic activity of Bi2O2CO3 and enhanced the absorption band of pure Bi2O2CO3. The photocatalytic activities of the Ag@AgCl/Bi2O2CO3 samples were determined by photocatalytic degradation of methylene blue (MB) under visible light irradiation. The Ag@AgCl (10 wt %)/Bi2O2CO3 composite showed the highest photocatalytic activity, degrading 97.9% MB after irradiation for 20 min, which is over 1.64 and 3.66 times faster than that of pure Ag@AgCl (calculated based on the equivalent Ag@AgCl content in Ag@AgCl (10 wt %)/Bi2O2CO3) and pure Bi2O2CO3, respectively. Bisphenol A (BPA) was also degraded to further prove the degradation ability of Ag@AgCl/Bi2O2CO3. Photocurrent studies indicated that the recombination of photo-generated electron–hole pairs was decreased effectively due to the formation of heterojunctions between flower-like Bi2O2CO3 and Ag@AgCl nanoparticles. Trapping experiments indicated that O2−, h+ and Cl° acted as the main reactive species for MB degradation in the present photocatalytic system. Furthermore, the cycling experiments revealed the good stability of Ag@AgCl/Bi2O2CO3 composites. Based on the above, a photocatalytic mechanism for the degradation of organic compounds over Ag@AgCl/Bi2O2CO3 was proposed. PMID:28773607

  18. 10-fold enhancement in light-driven water splitting using niobium oxynitride microcone array films

    KAUST Repository

    Shaheen, Basamat

    2016-03-26

    We demonstrate, for the first time, the synthesis of highly ordered niobium oxynitride microcones as an attractive class of materials for visible-light-driven water splitting. As revealed by the ultraviolet photoelectron spectroscopy (UPS), photoelectrochemical and transient photocurrent measurements, the microcones showed enhanced performance (~1000% compared to mesoporous niobium oxide) as photoanodes for water splitting with remarkable stability and visible light activity. © 2016 Elsevier B.V. All rights reserved.

  19. A light-driven artificial flytrap

    Science.gov (United States)

    Wani, Owies M.; Zeng, Hao; Priimagi, Arri

    2017-05-01

    The sophistication, complexity and intelligence of biological systems is a continuous source of inspiration for mankind. Mimicking the natural intelligence to devise tiny systems that are capable of self-regulated, autonomous action to, for example, distinguish different targets, remains among the grand challenges in biomimetic micro-robotics. Herein, we demonstrate an autonomous soft device, a light-driven flytrap, that uses optical feedback to trigger photomechanical actuation. The design is based on light-responsive liquid-crystal elastomer, fabricated onto the tip of an optical fibre, which acts as a power source and serves as a contactless probe that senses the environment. Mimicking natural flytraps, this artificial flytrap is capable of autonomous closure and object recognition. It enables self-regulated actuation within the fibre-sized architecture, thus opening up avenues towards soft, autonomous small-scale devices.

  20. Simultaneous determination and classification of riboflavin, thiamine, nicotinamide and pyridoxine in pharmaceutical formulations, by UV-visible spectrophotometry and multivariate analysis

    OpenAIRE

    López-de-Alba,Pedro L.; López-Martínez,Leticia; Cerdá,Vìctor; Amador-Hernández,Judith

    2006-01-01

    Soft Independent Modeling of Class Analogy and Partial Least Squares Regression were used in this work for the identification and quantification of thiamine, riboflavin, nicotinamide and pyridoxine by UV-Vis spectrophotometry, without separation or preconcentration steps in the analytical procedure. For quantitative purposes, the working range established was 1-14 mg L-1 for riboflavin, 2-26 mg L-1 for thiamine, 2-30 mg L-1 for nicotinamide, and 2-22 mg L-1 for pyridoxine. Recovery results hi...

  1. A light-driven sodium ion pump in marine bacteria.

    Science.gov (United States)

    Inoue, Keiichi; Ono, Hikaru; Abe-Yoshizumi, Rei; Yoshizawa, Susumu; Ito, Hiroyasu; Kogure, Kazuhiro; Kandori, Hideki

    2013-01-01

    Light-driven proton-pumping rhodopsins are widely distributed in many microorganisms. They convert sunlight energy into proton gradients that serve as energy source of the cell. Here we report a new functional class of a microbial rhodopsin, a light-driven sodium ion pump. We discover that the marine flavobacterium Krokinobacter eikastus possesses two rhodopsins, the first, KR1, being a prototypical proton pump, while the second, KR2, pumps sodium ions outward. Rhodopsin KR2 can also pump lithium ions, but converts to a proton pump when presented with potassium chloride or salts of larger cations. These data indicate that KR2 is a compatible sodium ion-proton pump, and spectroscopic analysis showed it binds sodium ions in its extracellular domain. These findings suggest that light-driven sodium pumps may be as important in situ as their proton-pumping counterparts.

  2. Design of BODIPY Dyes as Photosensitisers in Multicomponent Catalyst Systems for Light-Driven Hydrogen Production.

    Science.gov (United States)

    Dura, Laura; Ahrens, Johannes; Pohl, Marga-Martina; Höfler, Sebastian; Bröring, Martin; Beweries, Torsten

    2015-09-21

    A study of visible-light-driven hydrogen production using a multicomponent system consisting of different boron dipyrromethene (BODIPY) dyes, triethylamine and [{Pd(PPh3)Cl2}2] from THF/water mixtures is presented. A trio of meso-mesityl BODIPY dyes display the best activities and long-term stabilities of more than ten days with the 2,6-diiodo derivative showing the best performance. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. UV-light driven photocatalytic performance of hydrothermally-synthesized hexagonal CePO4 nanorods

    Science.gov (United States)

    Zhu, Zhongqi; Zhang, Ke; Zhao, Heyun; Zhu, Jing

    2017-10-01

    Hexagonal CePO4 nanorods were synthesized via a simple hydrothermal method without the presence of surfactants and then characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption and photoluminescence (PL) spectroscopy. UV-light driven photocatalytic activities of hexagonal CePO4 nanorods were detailedly demonstrated via degrading different organic dyes such as congo red (CR), organic rhodamine B (RB), methyl orange (MO) and methylene blue (MB) since these nanorods exhibit strong UV absorption with the cutoff edge of about 420 nm.

  4. Light-Driven Rotary Molecular Motors on Gold Nanoparticles

    NARCIS (Netherlands)

    Pollard, Michael M.; ter Wiel, Matthijs K. J.; van Delden, Richard A.; Vicario, Javier; Koumura, Nagatoshi; van den Brom, Coenraad R.; Meetsma, Auke; Feringa, Ben L.

    2008-01-01

    We report the synthesis of unidirectional light-driven rotary molecular motors based oil chiral overcrowded alkenes and their immobilisation on the surface of gold nanoparticles through two anchors. Using a combination of (1)H and (13)C NMR, UV/Vis and CD spectroscopy, we show that these motors

  5. Rate acceleration of light-driven rotary molecular motors

    NARCIS (Netherlands)

    Pollard, Michael M.; Klok, Martin; Pijper, Dirk; Feringa, Ben L.

    2007-01-01

    One of the key challenges in taking light-driven unidirectional rotary motors from discovery to application is to increase the rate of rotation. Herein, we review our ongoing efforts to address this issue by meticulous improvement to the molecular design. To accelerate the rotary cycle, we have

  6. Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications.

    Science.gov (United States)

    Bisoyi, Hari Krishna; Li, Quan

    2016-12-28

    Light-driven phenomena both in living systems and nonliving materials have enabled truly fascinating and incredible dynamic architectures with terrific forms and functions. Recently, liquid crystalline materials endowed with photoresponsive capability have emerged as enticing systems. In this Review, we focus on the developments of light-driven liquid crystalline materials containing photochromic components over the past decade. Design and synthesis of photochromic liquid crystals (LCs), photoinduced phase transitions in LC, and photoalignment and photoorientation of LCs have been covered. Photomodulation of pitch, polarization, lattice constant and handedness inversion of chiral LCs is discussed. Light-driven phenomena and properties of liquid crystalline polymers, elastomers, and networks have also been analyzed. The applications of photoinduced phase transitions, photoalignment, photomodulation of chiral LCs, and photomobile polymers have been highlighted wherever appropriate. The combination of photochromism, liquid crystallinity, and fabrication techniques has enabled some fascinating functional materials which can be driven by ultraviolet, visible, and infrared light irradiation. Nanoscale particles have been incorporated to widen and diversify the scope of the light-driven liquid crystalline materials. The developed materials possess huge potential for applications in optics, photonics, adaptive materials, nanotechnology, etc. The challenges and opportunities in this area are discussed at the end of the Review.

  7. Unidirectional light-driven molecular motors based on overcrowded alkenes.

    Science.gov (United States)

    Cnossen, Arjen; Browne, Wesley R; Feringa, Ben L

    2014-01-01

    Over the last two decades, interest in nanotechnology has led to the design and synthesis of a toolbox of nanoscale versions of macroscopic devices and components. In molecular nanotechnology, linear motors based on rotaxanes and rotary motors based on overcrowded alkenes are particularly promising for performing work at the nanoscale. In this chapter, progress on light-driven molecular motors based on overcrowded alkenes is reviewed. Both the so-called first and second generation molecular motors are discussed, as well as their potential applications.

  8. Third-Generation Light-Driven Symmetric Molecular Motors.

    Science.gov (United States)

    Kistemaker, Jos C M; Štacko, Peter; Roke, Diederik; Wolters, Alexander T; Heideman, G Henrieke; Chang, Mu-Chieh; van der Meulen, Pieter; Visser, Johan; Otten, Edwin; Feringa, Ben L

    2017-07-19

    Symmetric molecular motors based on two overcrowded alkenes with a notable absence of a stereogenic center show potential to function as novel mechanical systems in the development of more advanced nanomachines offering controlled motion over surfaces. Elucidation of the key parameters and limitations of these third-generation motors is essential for the design of optimized molecular machines based on light-driven rotary motion. Herein we demonstrate the thermal and photochemical rotational behavior of a series of third-generation light-driven molecular motors. The steric hindrance of the core unit exerted upon the rotors proved pivotal in controlling the speed of rotation, where a smaller size results in lower barriers. The presence of a pseudo-asymmetric carbon center provides the motor with unidirectionality. Tuning of the steric effects of the substituents at the bridgehead allows for the precise control of the direction of disrotary motion, illustrated by the design of two motors which show opposite rotation with respect to a methyl substituent. A third-generation molecular motor with the potential to be the fastest based on overcrowded alkenes to date was used to visualize the equal rate of rotation of both its rotor units. The autonomous rotational behavior perfectly followed the predicted model, setting the stage for more advanced motors for functional dynamic systems.

  9. Crystal structure of a light-driven sodium pump.

    Science.gov (United States)

    Gushchin, Ivan; Shevchenko, Vitaly; Polovinkin, Vitaly; Kovalev, Kirill; Alekseev, Alexey; Round, Ekaterina; Borshchevskiy, Valentin; Balandin, Taras; Popov, Alexander; Gensch, Thomas; Fahlke, Christoph; Bamann, Christian; Willbold, Dieter; Büldt, Georg; Bamberg, Ernst; Gordeliy, Valentin

    2015-05-01

    Recently, the first known light-driven sodium pumps, from the microbial rhodopsin family, were discovered. We have solved the structure of one of them, Krokinobacter eikastus rhodopsin 2 (KR2), in the monomeric blue state and in two pentameric red states, at resolutions of 1.45 Å and 2.2 and 2.8 Å, respectively. The structures reveal the ion-translocation pathway and show that the sodium ion is bound outside the protein at the oligomerization interface, that the ion-release cavity is capped by a unique N-terminal α-helix and that the ion-uptake cavity is unexpectedly large and open to the surface. Obstruction of the cavity with the mutation G263F imparts KR2 with the ability to pump potassium. These results pave the way for the understanding and rational design of cation pumps with new specific properties valuable for optogenetics.

  10. Visible-light-driven g-C3N4/Ti3+-TiO2 photocatalyst co-exposed {0 0 1} and {1 0 1} facets and its enhanced photocatalytic activities for organic pollutant degradation and Cr(VI) reduction

    Science.gov (United States)

    Lu, Dan; Zhang, Gaoke; Wan, Zhen

    2015-12-01

    Novel g-C3N4/Ti3+-TiO2 photocatalyst co-exposed {0 0 1} and {1 0 1} facets of TiO2 was synthesized via a hydrothermal-sonication assisted strategy. The photocatalytic activities of the as-obtained photocatalyst were evaluated by the degradation of rhodamine B (RhB) and the reduction of Cr(VI) under visible-light irradiation. It was found that the g-C3N4/Ti3+-TiO2 composites with 6 wt% g-C3N4 exhibited the highest visible-light photocatalytic efficiency, which is also higher than the pure g-C3N4 and Ti3+-TiO2. A possible photocatalytic mechanism was discussed on the basis of the theoretical analyses and scavenger experiments. Results show that holes (h+) and superoxide anions (rad O2-) reactive species participated in the degradation of RhB solution over the g-C3N4/Ti3+-TiO2 composites. The enhanced photocatalytic activities of g-C3N4/Ti3+-TiO2 composites can be attributed to the wide optical adsorption of g-C3N4 and Ti3+ as well as the effectively separation and transportation of photo-generated electrons and holes pairs, which was resulted from the surface heterojunction between the g-C3N4 and Ti3+-TiO2 nanosheets co-exposed {1 0 1} and {0 0 1} facets of anatase TiO2.

  11. Visible-light-driven g-C{sub 3}N{sub 4}/Ti{sup 3+}-TiO{sub 2} photocatalyst co-exposed {0 0 1} and {1 0 1} facets and its enhanced photocatalytic activities for organic pollutant degradation and Cr(VI) reduction

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Dan; Zhang, Gaoke, E-mail: gkzhang@whut.edu.cn; Wan, Zhen

    2015-12-15

    Graphical abstract: Schematic illustration for the mechanism of photo-generated charge carrier transfers in g-C{sub 3}N{sub 4}/Ti{sup 3+}-TiO{sub 2} photocatalyst and its visible-light photocatalytic performance. - Highlights: • g-C{sub 3}N{sub 4}/Ti{sup 3+}-TiO{sub 2} composite co-exposed {0 0 1} and {1 0 1} facets of TiO{sub 2} was synthesized. • RhB and Cr(VI) aqueous solutions were used to evaluate the photocatalytic activities. • h{sup +} and ·O{sub 2}{sup −} are the critical reactive species in the degradation of RhB solution. • Surface heterojunction of co-exposed {1 0 1} and {0 0 1} facets improve the separation. - Abstract: Novel g-C{sub 3}N{sub 4/}Ti{sup 3+}-TiO{sub 2} photocatalyst co-exposed {0 0 1} and {1 0 1} facets of TiO{sub 2} was synthesized via a hydrothermal–sonication assisted strategy. The photocatalytic activities of the as-obtained photocatalyst were evaluated by the degradation of rhodamine B (RhB) and the reduction of Cr(VI) under visible-light irradiation. It was found that the g-C{sub 3}N{sub 4}/Ti{sup 3+}-TiO{sub 2} composites with 6 wt% g-C{sub 3}N{sub 4} exhibited the highest visible-light photocatalytic efficiency, which is also higher than the pure g-C{sub 3}N{sub 4} and Ti{sup 3+}-TiO{sub 2}. A possible photocatalytic mechanism was discussed on the basis of the theoretical analyses and scavenger experiments. Results show that holes (h{sup +}) and superoxide anions (·O{sub 2}{sup −}) reactive species participated in the degradation of RhB solution over the g-C{sub 3}N{sub 4}/Ti{sup 3+}-TiO{sub 2} composites. The enhanced photocatalytic activities of g-C{sub 3}N{sub 4}/Ti{sup 3+}-TiO{sub 2} composites can be attributed to the wide optical adsorption of g-C{sub 3}N{sub 4} and Ti{sup 3+} as well as the effectively separation and transportation of photo-generated electrons and holes pairs, which was resulted from the surface heterojunction between the g-C{sub 3}N{sub 4} and Ti{sup 3+}-TiO{sub 2} nanosheets co-exposed {1

  12. A highly efficient visible-light-driven novel p-n junction Fe{sub 2}O{sub 3}/BiOI photocatalyst: Surface decoration of BiOI nanosheets with Fe{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mehraj, Owais; Pirzada, Bilal M.; Mir, Niyaz A.; Khan, Mohammad Zain; Sabir, Suhail, E-mail: sabirsuhail09@gmail.com

    2016-11-30

    Highlights: • BiOI/Fe{sub 2}O{sub 3}p-n heterojunctions were synthesized through an in-situ hydrolysis method under solvothermal conditions. • BiOI/Fe{sub 2}O{sub 3}p-n heterojunctions showed enhanced visible light activity than single BiOI. • BiOI/Fe{sub 2}O{sub 3}p-n heterojunctions showed improved stability than pure BiOI nanosheets. - Abstract: Novel xFe{sub 2}O{sub 3}/yBiOI composites (x/y = 0.25, 0.35, 0.45 molar ratios) with a p-n heterojunction were prepared for the first time through an in situ hydrolysis method under solvothermal conditions. The phase structure, morphology and optical properties of the composites were studied using several characterization tools including X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Fourier transform infrared (FTIR), N{sub 2} adsorption-desorption isotherms (BET) and UV–vis diffuse reflectance spectroscopy (UV-DRS). The characterization results suggest square shaped nanosheets of BiOI with Fe{sub 2}O{sub 3} nanoparticles well distributed on the surface of BiOI nanosheets. The photodegradation performances of the xFe/yBi samples were investigated using aqueous solution of Rhodamine B (RhB) dye. The xFe/yBi composites displayed much higher photocatalytic efficiencies for RhB degradation than the single BiOI under visible light (λ > 400 nm). Specifically, the degradation rate of xFe/yBi samples at molar ratio of 0.35 is 4.24 times higher than single BiOI. The novel Fe{sub 2}O{sub 3}/BiOI heterojunction was found to be highly stable in cyclic experiments. Based on the results of BET, PL and DRS analysis, the enhanced photocatalytic efficiency can be mainly ascribed to the formation of stable p-n heterojunction between Fe{sub 2}O{sub 3} and BiOI, which facilitates the transfer and separation of photogenerated electron-hole pairs.

  13. Full Solar Spectrum Light Driven Thermocatalysis with Extremely High Efficiency on Nanostructured Ce Ion Substituted OMS-2 Catalyst for VOCs Purification

    DEFF Research Database (Denmark)

    Hou, J.T.; Li, Y.Z.; Mao, M.Y.

    2015-01-01

    solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants such as benzene, toluene, and acetone. Based on the experimental evidence, we propose a novel...... in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full...... mechanism of solar light driven thermocatalysis for the Ce ion substituted OMS-2 catalyst. The reason why the Ce ion substituted OMS-2 catalyst exhibits much higher catalytic activity than pure OMS-2 and CeO2/OMS-2 nano composite under the full solar spectrum irradiation is discussed....

  14. Tuning the rotation rate of light-driven molecular motors.

    Science.gov (United States)

    Bauer, Jurica; Hou, Lili; Kistemaker, Jos C M; Feringa, Ben L

    2014-05-16

    Overcrowded alkenes are among the most promising artificial molecular motors because of their ability to undergo repetitive light-driven unidirectional rotary motion around the central C═C bond. The exceptional features of these molecules render them highly useful for a number of applications in nanotechnology. Many of these applications, however, would benefit from higher rotation rates. To this end, a new molecular motor was designed, and the isomerization processes were studied in detail. The new motor comprises a fluorene lower half and a five-membered-ring upper half; the upper-half ring is fused to a p-xylyl moiety and bears a tert-butyl group at the stereogenic center. The kinetics of the thermal isomerization was studied by low-temperature UV-vis spectroscopy as well as by transient absorption spectroscopy at room temperature. These studies revealed that the tert-butyl and p-xylyl groups in the five-membered-ring upper half may be introduced simultaneously in the molecular design to achieve an acceleration of the rotation rate of the molecular motor that is larger than the acceleration obtained by using either one of the two groups individually. Furthermore, the new molecular motor retains unidirectional rotation while showing remarkably high photostationary states.

  15. Near-infrared-light-driven artificial photosynthesis by nanobiocatalytic assemblies.

    Science.gov (United States)

    Lee, Joon Seok; Nam, Dong Heon; Kuk, Su Keun; Park, Chan Beum

    2014-03-24

    Artificial photosynthesis in nanobiocatalytic assemblies aims to reconstruct man-made photosensitizers, electron mediators, electron donors, and redox enzymes for solar synthesis of valuable chemicals through photochemical cofactor regeneration. Herein, we report, for the first time, on nanobiocatalytic artificial photosynthesis in near-infrared (NIR) light, which constitutes over 46% of the solar energy. For NIR-light-driven photoenzymatic synthesis, we synthesized silica-coated upconversion nanoparticles, Si-NaYF4:Yb,Er and Si-NaYF4:Yb,Tm, for efficient photon-conversion through Förster resonance energy transfer (FRET) with rose bengal (RB), a photosensitizer. We observed NIR-induced electron transfer by using linear sweep voltammetric analysis; this indicates that photoexcited electrons of RB/Si-NaYF4:Yb,Er are transferred to NAD+ through a Rh-based electron mediator. RB/Si-NaYF4:Yb,Er nanoparticles, which exhibit higher FRET efficiency due to more spectral overlap than RB/Si-NaYF4:Yb,Tm, perform much better in the photoenzymatic conversion. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Nicotinamide and the skin.

    Science.gov (United States)

    Chen, Andrew C; Damian, Diona L

    2014-08-01

    Nicotinamide, an amide form of vitamin B3, boosts cellular energy and regulates poly-ADP-ribose-polymerase 1, an enzyme with important roles in DNA repair and the expression of inflammatory cytokines. Nicotinamide shows promise for the treatment of a wide range of dermatological conditions, including autoimmune blistering disorders, acne, rosacea, ageing skin and atopic dermatitis. In particular, recent studies have also shown it to be a potential agent for reducing actinic keratoses and preventing skin cancers. © 2014 The Australasian College of Dermatologists.

  17. Photoprotective effects of nicotinamide.

    Science.gov (United States)

    Damian, Diona L

    2010-04-01

    Sun protective measures can reduce numbers of both precancerous actinic keratoses and cutaneous squamous cell carcinomas within relatively short periods of time even in high-risk populations. Sunscreens, which tend to provide greater protection against shortwave UVB than against longer wavelength UVA radiation, can however provide only partial protection from the mutagenic and immune suppressive effects of sunlight. In large part, this reflects poor compliance with proper sunscreen application and reapplication. Skin cancer is by far the most common malignancy in Caucasian populations, and additional strategies to reduce the morbidity and economic burden of this disease are now urgently needed. Nicotinamide, the amide form of vitamin B3, is an inexpensive agent which is used for a variety of dermatological applications with little or no toxicity even at high doses. Nicotinamide has photoprotective effects against carcinogenesis and immune suppression in mice, and is photoimmunoprotective in humans when used as a lotion or orally. UV irradiation depletes keratinocytes of cellular energy and nicotinamide, which is a precursor of nicotinamide adenine dinucleotide, may act at least in part by providing energy repletion to irradiated cells.

  18. Light-driven tipping points in polar ecosystems.

    Science.gov (United States)

    Clark, Graeme F; Stark, Jonathan S; Johnston, Emma L; Runcie, John W; Goldsworthy, Paul M; Raymond, Ben; Riddle, Martin J

    2013-12-01

    Some ecosystems can undergo abrupt transformation in response to relatively small environmental change. Identifying imminent 'tipping points' is crucial for biodiversity conservation, particularly in the face of climate change. Here, we describe a tipping point mechanism likely to induce widespread regime shifts in polar ecosystems. Seasonal snow and ice-cover periodically block sunlight reaching polar ecosystems, but the effect of this on annual light depends critically on the timing of cover within the annual solar cycle. At high latitudes, sunlight is strongly seasonal, and ice-free days around the summer solstice receive orders of magnitude more light than those in winter. Early melt that brings the date of ice-loss closer to midsummer will cause an exponential increase in the amount of sunlight reaching some ecosystems per year. This is likely to drive ecological tipping points in which primary producers (plants and algae) flourish and out-compete dark-adapted communities. We demonstrate this principle on Antarctic shallow seabed ecosystems, which our data suggest are sensitive to small changes in the timing of sea-ice loss. Algae respond to light thresholds that are easily exceeded by a slight reduction in sea-ice duration. Earlier sea-ice loss is likely to cause extensive regime shifts in which endemic shallow-water invertebrate communities are replaced by algae, reducing coastal biodiversity and fundamentally changing ecosystem functioning. Modeling shows that recent changes in ice and snow cover have already transformed annual light budgets in large areas of the Arctic and Antarctic, and both aquatic and terrestrial ecosystems are likely to experience further significant change in light. The interaction between ice-loss and solar irradiance renders polar ecosystems acutely vulnerable to abrupt ecosystem change, as light-driven tipping points are readily breached by relatively slight shifts in the timing of snow and ice-loss. © 2013 John Wiley & Sons Ltd.

  19. Ru(II)-diimine functionalized metalloproteins: From electron transfer studies to light-driven biocatalysis

    Science.gov (United States)

    Lam, Quan; Kato, Mallory; Cheruzel, Lionel

    2015-01-01

    The unique photochemical properties of Ru(II)-diimine complexes have helped initiate a series of seminal electron transfer studies in metalloenzymes. It has thus been possible to experimentally determine rate constants for long-range electron transfers. These studies have laid the foundation for the investigation of reactive intermediates in heme proteins and for the design of light-activated biocatalysts. Various metalloenzymes, such as hydrogenase, carbon monoxide dehydrogenase, nitrogenase, laccase and cytochrome P450 BM3 have been functionalized with Ru(II)-diimine complexes. Upon visible light-excitation, these photosensitized metalloproteins are capable of sustaining photocatalytic activity to reduce small molecules such as protons, acetylene, hydrogen cyanide and carbon monoxide or activate molecular dioxygen to produce hydroxylated products. The Ru(II)-diimine photosensitizers are hence able to deliver multiple electrons to metalloenzymes buried active sites circumventing the need for the natural redox partners. In this review, we will highlight the key achievements of the light-driven biocatalysts, which stem from the extensive electron transfer investigations. PMID:26392147

  20. Ru(II)-diimine functionalized metalloproteins: From electron transfer studies to light-driven biocatalysis.

    Science.gov (United States)

    Lam, Quan; Kato, Mallory; Cheruzel, Lionel

    2016-05-01

    The unique photochemical properties of Ru(II)-diimine complexes have helped initiate a series of seminal electron transfer studies in metalloenzymes. It has thus been possible to experimentally determine rate constants for long-range electron transfers. These studies have laid the foundation for the investigation of reactive intermediates in heme proteins and for the design of light-activated biocatalysts. Various metalloenzymes such as hydrogenase, carbon monoxide dehydrogenase, nitrogenase, laccase and cytochrome P450 BM3 have been functionalized with Ru(II)-diimine complexes. Upon visible light-excitation, these photosensitized metalloproteins are capable of sustaining photocatalytic activity to reduce small molecules such as protons, acetylene, hydrogen cyanide and carbon monoxide or activate molecular dioxygen to produce hydroxylated products. The Ru(II)-diimine photosensitizers are hence able to deliver multiple electrons to metalloenzymes buried active sites, circumventing the need for the natural redox partners. In this review, we will highlight the key achievements of the light-driven biocatalysts, which stem from the extensive electron transfer investigations. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Efficient Light-Driven Water Oxidation Catalysis by Dinuclear Ruthenium Complexes.

    Science.gov (United States)

    Berardi, Serena; Francàs, Laia; Neudeck, Sven; Maji, Somnath; Benet-Buchholz, Jordi; Meyer, Franc; Llobet, Antoni

    2015-11-01

    Mastering the light-induced four-electron oxidation of water to molecular oxygen is a key step towards the achievement of overall water splitting to produce alternative solar fuels. In this work, we report two rugged molecular pyrazolate-based diruthenium complexes that efficiently catalyze visible-light-driven water oxidation. These complexes were fully characterized both in the solid state (by X-ray diffraction analysis) and in solution (spectroscopically and electrochemically). Benchmark performances for homogeneous oxygen production have been obtained for both catalysts in the presence of a photosensitizer and a sacrificial electron acceptor at pH 7, and a turnover frequency of up to 11.1 s(-1) and a turnover number of 5300 were obtained after three successive catalytic runs. Under the same experimental conditions with the same setup, the pyrazolate-based diruthenium complexes outperform other well-known water oxidation catalysts owing to both electrochemical and mechanistic aspects. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Cadmium sulfide with tunable morphologies: Preparation and visible-light driven photocatalytic performance

    Science.gov (United States)

    Fang, Zhi; Zhang, Liqin; Yang, Tao; Su, Lei; Chou, Kuo-Chih; Hou, Xinmei

    2017-09-01

    Wurtzite cadmium sulfide (CdS) with four kinds of morphologies including dendrites, flowers, multipods and spheres, were tunably prepared using a facile and simple hydrothermal route with an assistance of N,N-dimethylformamide (DMF). The formation mechanism of CdS with different morphologies was discussed based on the phase and microstructure characterization by X-ray diffraction (XRD) and field emission scanning electronic microscopy (FE-SEM) with energy dispersive spectrometer (EDS). The effect of morphology on the photoelectrochemical (PEC) performance was investigated using linear sweep voltammetry (LSV), photocurrent versus irradiation time curve (I-t) and electrochemical impedance spectroscope (EIS). The results show that the dendrite-like CdS exhibits the highest photocurrent density with 0.748 mA/cm2 at 0.253 V. The photodegradation of Rhodamine B (RhB) further proves the dendrite-like CdS possesses excellent photocatalytic (PC) performance, which could be mainly attributed to the unique hyperbranched structure, larger surface area and smaller crystal size.

  3. Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

    OpenAIRE

    Subas K. Muduli; Songling Wang; Shi Chen; Chin Fan Ng; Cheng Hon Alfred Huan; Tze Chien Sum; Han Sen Soo

    2014-01-01

    A facile, solvothermal synthesis of mesoporous cerium oxide nanospheres is reported for the purpose of the photocatalytic degradation of organic dyes and future applications in sustainable energy research. The earth-abundant, relatively affordable, mixed valence cerium oxide sample, which consists of predominantly Ce7O12, has been characterized by powder X-ray diffraction, X-ray photoelectron and UV–vis spectroscopy, and transmission electron microscopy. Together with N2 sorption experiments,...

  4. Light-driven oxidation of polysaccharides by photosynthetic pigments and a metalloenzyme

    DEFF Research Database (Denmark)

    Cannella, David; Möllers, K. Benedikt; Frigaard, Niels-Ulrik

    2016-01-01

    the effect of using excited photosynthetic pigments as electron donors. LPMOs combined with pigments and reducing agents were exposed to light, which resulted in a never before seen 100-fold increase in catalytic activity. In addition, LPMO substrate specificity was broadened to include both cellulose...... and hemicellulose. LPMO enzymes and pigment derivatives common in the environment of plant-degrading organisms thus form a highly reactive and stable light-driven system increasing the turnover rate and versatility of LPMOs. This light-driven system may find applications in biotechnology and chemical processing....

  5. LDRD final report on nanovehicle light-driven propulsion.

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anup K.; van Swol, Frank B.; Shelnutt, John Allen; Medforth, Craig J.; Song, Yujiang

    2004-12-01

    Having demonstrated the possibility of constructing nanoscale metallic vehicular bodies as described in last year's proposal, our goals have been to make uniform preparations of the metallized lipid assemblies and to determine the feasibility of powering these nanostructures with biological motors that are activated and driven by visible light. We desired that the propulsion system be constructed entirely by self-assembly and powered by a photocatalytic process partially already built into the nanovehicle. The nanovehicle we desire to build is composed of both natural biological components (ATPase, kinesin-microtubules) and biomimetic components (platinized liposomes, photosynthetic membrane) as functional units. The vehicle's body was originally envisioned to be composed of a surfactant liposomal bilayer coated with platinum nanoparticles, but instead of the expected nanoparticles we were able to grow dendritic 2-nm thick platinum sheets on the liposomes. Now, we have shown that it is possible to completely enclose the liposomes with sheeting to form porous platinum spheres, which show good structural stability as evidenced by their ability to survive the stresses of electron-microscopy sample preparation. Our goals were to control the synthesis of the platinized liposomes well enough to make uniform preparations of the coated individual liposomes and to develop the propulsion system for these nanovehicles a hydrogen-evolving artificial photosynthetic system in the liposomal bilayer that generates the pH gradient across the membrane that is necessary to drive the synthesis of ATP by ATP-synthase incorporated in the membrane. ATP produced would fuel the molecular motor (kinesin) attached to the vehicle, needing only light, storable ADP, phosphate, and an electron donor to be produced by ATP-synthase in the membrane. These research goals appear to be attainable, but growing the uniform preparations of the liposomes coated with dendritic platinum sheeting

  6. Structural basis for Na(+) transport mechanism by a light-driven Na(+) pump.

    Science.gov (United States)

    Kato, Hideaki E; Inoue, Keiichi; Abe-Yoshizumi, Rei; Kato, Yoshitaka; Ono, Hikaru; Konno, Masae; Hososhima, Shoko; Ishizuka, Toru; Hoque, Mohammad Razuanul; Kunitomo, Hirofumi; Ito, Jumpei; Yoshizawa, Susumu; Yamashita, Keitaro; Takemoto, Mizuki; Nishizawa, Tomohiro; Taniguchi, Reiya; Kogure, Kazuhiro; Maturana, Andrés D; Iino, Yuichi; Yawo, Hiromu; Ishitani, Ryuichiro; Kandori, Hideki; Nureki, Osamu

    2015-05-07

    Krokinobacter eikastus rhodopsin 2 (KR2) is the first light-driven Na(+) pump discovered, and is viewed as a potential next-generation optogenetics tool. Since the positively charged Schiff base proton, located within the ion-conducting pathway of all light-driven ion pumps, was thought to prohibit the transport of a non-proton cation, the discovery of KR2 raised the question of how it achieves Na(+) transport. Here we present crystal structures of KR2 under neutral and acidic conditions, which represent the resting and M-like intermediate states, respectively. Structural and spectroscopic analyses revealed the gating mechanism, whereby the flipping of Asp116 sequesters the Schiff base proton from the conducting pathway to facilitate Na(+) transport. Together with the structure-based engineering of the first light-driven K(+) pumps, electrophysiological assays in mammalian neurons and behavioural assays in a nematode, our studies reveal the molecular basis for light-driven non-proton cation pumps and thus provide a framework that may advance the development of next-generation optogenetics.

  7. Facile assembly of light-driven molecular motors onto a solid surface.

    Science.gov (United States)

    Chen, Jiawen; Chen, Kuang-Yen; Carroll, Gregory T; Feringa, Ben L

    2014-10-28

    In order to improve the rotary motion of surface assembled light-driven molecular motors, tetra-acid-functionalized motors were bound to an amine-coated quartz surface without prior activation of the acid groups. In contrast to earlier bipodal motors, the tetravalent motor showed no significant reduction in the rotation speed when attached to a surface.

  8. Increased speed of rotation for the smallest light-driven molecular motor

    NARCIS (Netherlands)

    ter Wiel, MKJ; van Delden, RA; Meetsma, A; Feringa, BL; Delden, Richard A. van; Feringa, Bernard

    2003-01-01

    In this paper we present the smallest artificial light-driven molecular motor consisting of only 28 carbon and 24 hydrogen atoms. The concept of controlling directionality of rotary movement at the molecular level by introduction of a stereogenic center next to the central olefinic bond of a

  9. Nicotinamide for skin cancer chemoprevention.

    Science.gov (United States)

    Damian, Diona L

    2017-08-01

    Nicotinamide (vitamin B 3 ) has a range of photoprotective effects in vitro and in vivo; it enhances DNA repair, reduces UV radiation-induced suppression of skin immune responses, modulates inflammatory cytokine production and skin barrier function and restores cellular energy levels after UV exposure. Pharmacological doses of nicotinamide have been shown to reduce actinic keratoses and nonmelanoma skin cancer incidence in high-risk individuals, making this a nontoxic and accessible option for skin cancer chemoprevention in this population. © 2017 The Australasian College of Dermatologists.

  10. Asymmetric Synthesis of Second-Generation Light-Driven Molecular Motors.

    Science.gov (United States)

    van Leeuwen, Thomas; Danowski, Wojciech; Otten, Edwin; Wezenberg, Sander J; Feringa, Ben L

    2017-05-19

    The enantiomeric homogeneity of light-driven molecular motors based on overcrowded alkenes is crucial in their application as either unidirectional rotors or as chiral multistate switches. It was challenging to obtain these compounds as single enantiomers via the established synthetic procedures due to loss of optical purity in the key step, i.e., the Barton-Kellogg olefination reaction. Searching for strategies to avoid racemization, a new class of light-driven molecular motors was designed, synthesized, and studied. The stereochemical integrity was fully preserved throughout the synthesis, and on the basis of photochemical and kinetic studies using UV/vis, CD, and 1 H NMR spectroscopy, it was established that they still function properly as unidirectional molecular motors.

  11. Simultaneous quantitation of nicotinamide riboside, nicotinamide mononucleotide and nicotinamide adenine dinucleotide in milk by a novel enzyme-coupled assay.

    Science.gov (United States)

    Ummarino, Simone; Mozzon, Massimo; Zamporlini, Federica; Amici, Adolfo; Mazzola, Francesca; Orsomando, Giuseppe; Ruggieri, Silverio; Raffaelli, Nadia

    2017-04-15

    Nicotinamide riboside, the most recently discovered form of vitamin B3, and its phosphorylated form nicotinamide mononucleotide, have been shown to be potent supplements boosting intracellular nicotinamide adenine dinucleotide (NAD) levels, thus preventing or ameliorating metabolic and mitochondrial diseases in mouse models. Here we report for the first time on the simultaneous quantitation of nicotinamide riboside, nicotinamide mononucleotide and NAD in milk by means of a fluorometric, enzyme-coupled assay. Application of this assay to milk from different species revealed that the three vitamers were present in human and donkey milk, while being selectively distributed in the other milks. Human milk was the richest source of nicotinamide mononucleotide. Overall, the three vitamers accounted for a significant fraction of total vitamin B3 content. Pasteurization did not affect the bovine milk content of nicotinamide riboside, whereas UHT processing fully destroyed the vitamin. In human milk, NAD levels were significantly affected by the lactation time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Solar to Liquid Fuels Production: Light-Driven Reduction of Carbon Dioxide to Formic Acid

    Science.gov (United States)

    2014-03-29

    AFRL-OSR-VA-TR-2014-0088 SOLAR TO LIQUID FUELS PRODUCTION: LIGHT-DRIVEN REDUCTION OF CARBON DIOXIDE TO FO John Golbeck PENNSYLVANIA STATE UNIVERSITY... Carbon Dioxide to Formic Acid Project FA9550-09-1-0671 was funded to generate formic acid from CO2 using sunlight as the source of energy. The... fuel cell technology have made formic acid an attractive alternative to methanol (which requires a more complicated 6- electron reduction of CO2) or

  13. Mutant of a Light-Driven Sodium Ion Pump Can Transport Cesium Ions.

    Science.gov (United States)

    Konno, Masae; Kato, Yoshitaka; Kato, Hideaki E; Inoue, Keiichi; Nureki, Osamu; Kandori, Hideki

    2016-01-07

    Krokinobacter eikastus rhodopsin 2 (KR2) is a light-driven Na(+) pump found in marine bacterium. KR2 pumps Li(+) and Na(+), but it becomes an H(+) pump in the presence of K(+), Rb(+), and Cs(+). Site-directed mutagenesis of the cytoplasmic surface successfully converted KR2 into a light-driven K(+) pump, suggesting that ion selectivity is determined at the cytoplasmic surface. Here we extended this research and successfully created a light-driven Cs(+) pump. KR2 N61L/G263F pumps Cs(+) as well as other monovalent cations in the presence of a protonophore. Ion-transport activities correlated with the additive volume of the residues at 61 and 263. The result suggests that an ion-selectivity filter is affected by these two residues and functions by strict exclusion of K(+) and larger cations in the wild type (N61/G263). In contrast, introduction of large residues possibly destroys local structures of the ion-selectivity filter, leading to the permeation of K(+) (P61/W263) and Cs(+) (L61/F263).

  14. Braking of a Light-Driven Molecular Rotary Motor by Chemical Stimuli.

    Science.gov (United States)

    van Leeuwen, Thomas; Danowski, Wojciech; Pizzolato, Stefano F; Štacko, Peter; Wezenberg, Sander J; Feringa, Ben L

    2018-01-02

    Artificial molecular motors hold great promise for application in responsive functional materials as well as to control the properties of biohybrid systems. Herein a strategy is reported to modulate the rotation of light-driven molecular motors. That is, the rotary speed of a molecular motor, functionalized with a biphenol moiety, could be decreased in situ by non-covalent substrate binding, as was established by 1 H NMR and UV/Vis spectroscopy. These findings constitute an important step in the development of multi-responsive molecular machinery. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Light-driven nano-robotics for sub-diffraction probing and sensing

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Bañas, Andrew Rafael; Palima, Darwin

    for exploiting optical forces and sensing in micro-robotic actuation and control. Advancing light-driven micro-robotics requires the optimization of optical forces and torques that, in turn, requires optimization of the underlying light-matter interaction. The requirement of having tightly focused beams...... exploit the light shaping capabilities available in the workstation to demonstrate a new strategy for controlling microstructures that goes beyond the typical refractive light deflections that are exploited in conventional optical trapping and manipulation. We also propose designing micro...

  16. A synthetic, light-driven consortium of cyanobacteria and heterotrophic bacteria enables stable polyhydroxybutyrate production.

    Science.gov (United States)

    Weiss, Taylor L; Young, Eric J; Ducat, Daniel C

    2017-10-20

    We previously reported that Synechococcus elongatus PCC 7942, engineered with the sucrose transporter CscB, can export up to 85% of its photosynthetically-fixed carbon as sucrose and shows considerable promise as an alternative carbohydrate source. One approach to effectively utilize this cyanobacterium is to generate synthetic, light-driven consortia in which sucrose-metabolizing heterotrophs catalyze the conversion of the low-value carbohydrate into higher-value compounds in co-culture. Here, we report an improved synthetic photoautotroph/chemoheterotroph consortial design in which sucrose secreted by S. elongatus CscB directly supports the bacterium Halomonas boliviensis, a natural producer of the bioplastic precursor, PHB. We show that alginate encapsulation of S. elongatus CscB enhances sucrose-export rates ~2-fold within 66h, to ~290mg sucrose L(-1)d(-1) OD750(-1) and enhances the co-culture stability. Consortial H. boliviensis accumulate up to 31% of their dry-weight as PHB, reaching productivities up to 28.3mg PHB L(-1)d(-1). This light-driven, alginate-partitioned co-culture platform achieves PHB productivities that match or exceed those of traditionally engineered cyanobacterial monocultures. Importantly, S. elongatus CscB/H. boliviensis co-cultures were continuously productive for over 5 months and resisted invasive microbial species without the application of antibiotics or other chemical selection agents. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  17. Direct Observation of a Dark State in the Photocycle of a Light-Driven Molecular Motor.

    Science.gov (United States)

    Amirjalayer, Saeed; Cnossen, Arjen; Browne, Wesley R; Feringa, Ben L; Buma, Wybren J; Woutersen, Sander

    2016-11-03

    Controlling the excited-state properties of light driven molecular machines is crucial to achieving high efficiency and directed functionality. A key challenge in achieving control lies in unravelling the complex photodynamics and especially in identifying the role played by dark states. Here we use the structure sensitivity and high time resolution of UV-pump/IR-probe spectroscopy to build a detailed and comprehensive model of the structural evolution of light driven molecular rotors. The photodynamics of these chiral overcrowded alkene derivatives are determined by two close-lying excited electronic states. The potential energy landscape of these "bright" and "dark" states gives rise to a broad excited-state electronic absorption band over the entire mid-IR range that is probed for the first time and modeled by quantum mechanical calculations. The transient IR vibrational fingerprints observed in our studies allow for an unambiguous identification of the identity of the "dark" electronic excited state from which the photon's energy is converted into motion, and thereby pave the way for tuning the quantum yield of future molecular rotors based on this structural motif.

  18. Light driven CO2 fixation by using cyanobacterial photosystem I and NADPH-dependent formate dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Masaki Ihara

    Full Text Available The ultimate goal of this research is to construct a new direct CO2 fixation system using photosystems in living algae. Here, we report light-driven formate production from CO2 by using cyanobacterial photosystem I (PS I. Formate, a chemical hydrogen carrier and important industrial material, can be produced from CO2 by using the reducing power and the catalytic function of formate dehydrogenase (FDH. We created a bacterial FDH mutant that experimentally switched the cofactor specificity from NADH to NADPH, and combined it with an in vitro-reconstituted cyanobacterial light-driven NADPH production system consisting of PS I, ferredoxin (Fd, and ferredoxin-NADP(+-reductase (FNR. Consequently, light-dependent formate production under a CO2 atmosphere was successfully achieved. In addition, we introduced the NADPH-dependent FDH mutant into heterocysts of the cyanobacterium Anabaena sp. PCC 7120 and demonstrated an increased formate concentration in the cells. These results provide a new possibility for photo-biological CO2 fixation.

  19. Enhancement of survival and electricity production in an engineered bacterium by light-driven proton pumping.

    Science.gov (United States)

    Johnson, Ethan T; Baron, Daniel B; Naranjo, Belén; Bond, Daniel R; Schmidt-Dannert, Claudia; Gralnick, Jeffrey A

    2010-07-01

    Microorganisms can use complex photosystems or light-dependent proton pumps to generate membrane potential and/or reduce electron carriers to support growth. The discovery that proteorhodopsin is a light-dependent proton pump that can be expressed readily in recombinant bacteria enables development of new strategies to probe microbial physiology and to engineer microbes with new light-driven properties. Here, we describe functional expression of proteorhodopsin and light-induced changes in membrane potential in the bacterium Shewanella oneidensis strain MR-1. We report that there were significant increases in electrical current generation during illumination of electrochemical chambers containing S. oneidensis expressing proteorhodopsin. We present evidence that an engineered strain is able to consume lactate at an increased rate when it is illuminated, which is consistent with the hypothesis that proteorhodopsin activity enhances lactate uptake by increasing the proton motive force. Our results demonstrate that there is coupling of a light-driven process to electricity generation in a nonphotosynthetic engineered bacterium. Expression of proteorhodopsin also preserved the viability of the bacterium under nutrient-limited conditions, providing evidence that fulfillment of basic energy needs of organisms may explain the widespread distribution of proteorhodopsin in marine environments.

  20. Synthesis, characterization and evaluation of the photocatalytic performance of Ag-CdMoO{sub 4} solar light driven plasmonic photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, Rajesh; Malla, Shova; Gyawali, Gobinda [Research Center for Eco-Multifunctional Nanomaterials, Sun Moon University (Korea, Republic of); Sekino, Tohru [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University (Japan); Lee, Soo Wohn, E-mail: swlee@sunmoon.ac.kr [Department of Environmental Engineering, Sun Moon University, Asan Si, Chungnam 336-708 (Korea, Republic of)

    2013-09-01

    Graphical abstract: - Highlights: • Ag-CdMoO{sub 4} solar light driven photocatalyst was successfully synthesized. • Photocatalyst exhibited strong absorption in the visible region. • Photocatalytic activity was significantly enhanced. • Enhanced activity was caused by the SPR effect induced by Ag nanoparticles. - Abstract: Ag-CdMoO{sub 4} plasmonic photocatalyst was synthesized in ethanol/water mixture by photo assisted co-precipitation method at room temperature. As synthesized powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) surface area analyzer. Photocatalytic activity was evaluated by performing the degradation experiment over methylene blue (MB) and indigo carmine (IC) as model dyes under simulated solar light irradiation. The results revealed that the Ag-CdMoO{sub 4} showed the higher photocatalytic performance as compared to CdMoO{sub 4} nanoparticles. Dispersion of Ag nanoparticles over the surface of CdMoO{sub 4} nanoparticles causes the surface plasmon resonance (SPR) and enhances the broad absorption in the entire visible region of the solar spectrum. Hence, dispersion of Ag nanoparticles over CdMoO{sub 4} nanoparticles could be the better alternative to enhance the absorption of visible light by scheelite crystal family for effective photocatalysis.

  1. The light-driven sodium ion pump: A new player in rhodopsin research.

    Science.gov (United States)

    Kato, Hideaki E; Inoue, Keiichi; Kandori, Hideki; Nureki, Osamu

    2016-12-01

    Rhodopsins are one of the most studied photoreceptor protein families, and ion-translocating rhodopsins, both pumps and channels, have recently attracted broad attention because of the development of optogenetics. Recently, a new functional class of ion-pumping rhodopsins, an outward Na(+) pump, was discovered, and following structural and functional studies enable us to compare three functionally different ion-pumping rhodopsins: outward proton pump, inward Cl(-) pump, and outward Na(+) pump. Here, we review the current knowledge on structure-function relationships in these three light-driven pumps, mainly focusing on Na(+) pumps. A structural and functional comparison reveals both unique and conserved features of these ion pumps, and enhances our understanding about how the structurally similar microbial rhodopsins acquired such diverse functions. We also discuss some unresolved questions and future perspectives in research of ion-pumping rhodopsins, including optogenetics application and engineering of novel rhodopsins. © 2016 The Authors. BioEssays Published by WILEY Periodicals, Inc.

  2. Proteorhodopsin from Dokdonia sp. PRO95 is a light-driven Na+-pump.

    Science.gov (United States)

    Bertsova, Y V; Bogachev, A V; Skulachev, V P

    2015-04-01

    The gene encoding proteorhodopsin AEX55013 from Dokdonia sp. PRO95 was cloned and expressed in Escherichia coli cells. Illumination of the proteorhodopsin-producing E. coli cells in Na+-containing media resulted in alkalinization of the media. This response was accelerated by uncoupler CCCP and inhibited by penetrating anion SCN(-). Illumination of the cells in a sodium-free medium (made by substituting Na+ with K+) resulted in SCN(-)-stimulated and CCCP-sensitive acidification of the medium. Illumination of the proteorhodopsin-containing E. coli cells caused CCCP-resistant transmembrane sodium export from these cells. We conclude that the proteorhodopsin from the marine flavobacterium Dokdonia sp. PRO95 is a primary light-driven Na+-pump. A high level of the heterologous production in E. coli cells as well as stability and purity of the isolated protein makes this proteorhodopsin an attractive model for studying the mechanism of active sodium transmembrane translocation.

  3. Integration of Enzymes in Polyaniline-Sensitized 3D Inverse Opal TiO2 Architectures for Light-Driven Biocatalysis and Light-to-Current Conversion.

    Science.gov (United States)

    Riedel, Marc; Lisdat, Fred

    2018-01-10

    Inspired by natural photosynthesis, coupling of artificial light-sensitive entities with biocatalysts in a biohybrid format can result in advanced photobioelectronic systems. Herein, we report on the integration of sulfonated polyanilines (PMSA1) and PQQ-dependent glucose dehydrogenase (PQQ-GDH) into inverse opal TiO2 (IO-TiO2) electrodes. While PMSA1 introduces sensitivity for visible light into the biohybrid architecture and ensures the efficient wiring between the IO-TiO2 electrode and the biocatalytic entity, PQQ-GDH provides the catalytic activity for the glucose oxidation and therefore feeds the light-driven reaction with electrons for an enhanced light-to-current conversion. Here, the IO-TiO2 electrodes with pores of around 650 nm provide a suitable interface and morphology needed for the stable and functional assembly of polymer and enzyme. The IO-TiO2 electrodes have been prepared by a template approach applying spin coating, allowing an easy scalability of the electrode height and surface area. The successful integration of the polymer and the enzyme is confirmed by the generation of an anodic photocurrent, showing an enhanced magnitude with increasing glucose concentrations. Compared to flat and nanostructured TiO2 electrodes, the three-layered IO-TiO2 electrodes give access to a 24-fold and 29-fold higher glucose-dependent photocurrent due to the higher polymer and enzyme loading in IO films. The three-dimensional IO-TiO2|PMSA1|PQQ-GDH architecture reaches maximum photocurrent densities of 44.7 ± 6.5 μA cm-2 at low potentials in the presence of glucose (for a three TiO2 layer arrangement). The onset potential for the light-driven substrate oxidation is found to be at -0.315 V vs Ag/AgCl (1 M KCl) under illumination with 100 mW cm-2, which is more negative than the redox potential of the enzyme. The results demonstrate the advantageous properties of IO-TiO2|PMSA1|PQQ-GDH biohybrid architectures for the light-driven glucose conversion with improved

  4. Light-Driven Contact Hearing Aid for Broad-Spectrum Amplification: Safety and Effectiveness Pivotal Study.

    Science.gov (United States)

    Gantz, Bruce J; Perkins, Rodney; Murray, Michael; Levy, Suzanne Carr; Puria, Sunil

    2017-03-01

    Demonstrate safety and effectiveness of the light-driven contact hearing aid to support FDA clearance. A single-arm, open-label investigational-device clinical trial. Two private-practice and one hospital-based ENT clinics. Forty-three subjects (86 ears) with mild-to-severe bilateral sensorineural hearing impairment. Bilateral amplification delivered via a light-driven contact hearing aid comprising a Tympanic Lens (Lens) with a customized platform to directly drive the umbo and a behind-the-ear sound processor (Processor) that encodes sound into light pulses to wirelessly deliver signal and power to the Lens. The primary safety endpoint was a determination of "no change" (PTA4 hearing at the 120-day measurement interval. The primary efficacy endpoint was improvement in word recognition using NU-6 at the 30-day measurement interval over the baseline unaided case. Secondary efficacy endpoints included functional gain from 2 to 10 kHz and speech-in-noise improvement over the baseline unaided case using both omnidirectional and directional microphones. The results for the 86 ears in the study determined a mean change of -0.40 dB in PTA4, indicating no change in residual hearing (p Hearing in Noise Test was 0.75 dB (p = 0.028) and 3.14 dB (p < 0.0001) for the omnidirectional and directional microphone modes, respectively. The safety and effectiveness data supported a de novo 510(k) submission that received clearance from the FDA.

  5. Nicotinic acid, nicotinamide, and nicotinamide riboside: a molecular evaluation of NAD+ precursor vitamins in human nutrition.

    Science.gov (United States)

    Bogan, Katrina L; Brenner, Charles

    2008-01-01

    Although baseline requirements for nicotinamide adenine dinucleotide (NAD+) synthesis can be met either with dietary tryptophan or with less than 20 mg of daily niacin, which consists of nicotinic acid and/or nicotinamide, there is growing evidence that substantially greater rates of NAD+ synthesis may be beneficial to protect against neurological degeneration, Candida glabrata infection, and possibly to enhance reverse cholesterol transport. The distinct and tissue-specific biosynthetic and/or ligand activities of tryptophan, nicotinic acid, nicotinamide, and the newly identified NAD+ precursor, nicotinamide riboside, reviewed herein, are responsible for vitamin-specific effects and side effects. Because current data suggest that nicotinamide riboside may be the only vitamin precursor that supports neuronal NAD+ synthesis, we present prospects for human nicotinamide riboside supplementation and propose areas for future research.

  6. Role of Nicotinamide in DNA Damage, Mutagenesis, and DNA Repair

    OpenAIRE

    Surjana, Devita; Halliday, Gary M.; Damian, Diona L.

    2010-01-01

    Nicotinamide is a water-soluble amide form of niacin (nicotinic acid or vitamin B3). Both niacin and nicotinamide are widely available in plant and animal foods, and niacin can also be endogenously synthesized in the liver from dietary tryptophan. Nicotinamide is also commercially available in vitamin supplements and in a range of cosmetic, hair, and skin preparations. Nicotinamide is the primary precursor of nicotinamide adenine dinucleotide (NAD+), an essential coenzyme in ATP production a...

  7. Role of Asn112 in a Light-Driven Sodium Ion-Pumping Rhodopsin.

    Science.gov (United States)

    Abe-Yoshizumi, Rei; Inoue, Keiichi; Kato, Hideaki E; Nureki, Osamu; Kandori, Hideki

    2016-10-18

    Light-driven outward sodium-pumping rhodopsin (NaR) was recently found in marine bacteria. Krokinobacter eikastus rhodopsin 2 (KR2) actively transports sodium and lithium ions in NaCl and LiCl, respectively, while it pumps protons in KCl. NaR has a conserved NDQ (N112, D116, and Q123 in KR2) motif, and previous studies suggested an important role for N112 in the function of KR2. Here we replaced N112 with 19 different amino acids and studied the molecular properties of the mutants. All mutants exhibited absorption bands from a protonated Schiff base in the λmax range from 508 to 531 nm upon heterologous expression in Escherichia coli, whose ion-pumping activity was measured using pH electrodes. The function of these mutants was classified into three phenotypes: wild-type (WT)-like Na(+)/H(+) compatible pump, exclusive H(+) pump, and no pump. Among the 19 mutants, only N112D, -G, -S, and -T showed light-driven Na(+) pump activity, N112A, -C, -P, -V, -E, -Q, -I, -L, -M, -F, and -W were exclusively H(+) pumps, and N112H, -K, -Y, and -R exhibited no pump activity. The mutants of the no pump function lack a blue-shifted M intermediate, indicating that Schiff base deprotonation is a prerequisite for Na(+) and H(+) pumps. In contrast, the subsequent red-shifted O intermediate was observed for WT and N112V but absent for N112T and N112A, suggesting that observation of this intermediate depends on kinetics. Although N112D, -G, -S, and -T are able to pump Na(+), they also pump H(+) in NaCl, where Na(+) and H(+) pumps compete with each other because of the decreased Na(+) uptake efficiency. From these facts, an exclusive Na(+) pump in NaCl exists only in WT. We conclude that N112 is one of the functional determinants of NaR.

  8. Nicotinamide phosphoribosyltransferase inhibitors, design, preparation and SAR

    DEFF Research Database (Denmark)

    Christensen, Mette Knak; Erichsen, Kamille Dumong; Olesen, Uffe Hogh

    2013-01-01

    Existing pharmacological inhibitors for nicotinamide phosphoribosyltransferase (NAMPT) are promising therapeutics for treating cancer. Using medicinal and computational chemistry methods, the structure-activity relationship for novel classes of NAMPT inhibitors is described and compounds optimize...

  9. Nicotinamide -Methyltransferase in Health and Cancer

    Directory of Open Access Journals (Sweden)

    David B Ramsden

    2017-06-01

    Full Text Available Over the past decade, the roles of nicotinamide N -methyltransferase and its product 1-methyl nicotinamide have emerged from playing merely minor roles in phase 2 xenobiotic metabolism as actors in some of the most important scenes of human life. In this review, the structures of the gene, messenger RNA, and protein are discussed, together with the role of the enzyme in many of the common cancers that afflict people today.

  10. A Model for the Molecular Mechanism of an Engineered Light-Driven Protein Machine.

    Science.gov (United States)

    Hoersch, Daniel; Kortemme, Tanja

    2016-04-05

    Controllable protein-based machines and materials are of considerable interest for diverse biotechnological applications. We previously re-engineered an ATP-driven protein machine, a group II chaperonin, to function as a light-gated nanocage. Here we develop and test a model for the molecular mechanism of the re-engineered chaperonin, which undergoes a large-scale closed to open conformational change triggered by reversible photo-isomerization of a site-specifically attached azobenzene crosslinker. In silico experiments using all-atom simulations suggest that rigid body motions of protein subdomains couple the length changes of the crosslinker to rearrangements of the nucleotide-binding pocket, leading to cage opening. We tested this model by designing a mutant for which the orientation of the two protein subdomains forming the nucleotide-binding pocket is directly controlled by the crosslinker, and confirmed successful reversible photoswitching in vitro. The model probes the conformational cycle of group II chaperonins and offers a design principle for engineering other light-driven protein-based molecular machines. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. From Extended Nanofluidics to an Autonomous Solar-Light-Driven Micro Fuel-Cell Device.

    Science.gov (United States)

    Pihosh, Yuriy; Uemura, Jin; Turkevych, Ivan; Mawatari, Kazuma; Kazoe, Yutaka; Smirnova, Adelina; Kitamori, Takehiko

    2017-07-03

    Autonomous micro/nano mechanical, chemical, and biomedical sensors require persistent power sources scaled to their size. Realization of autonomous micro-power sources is a challenging task, as it requires combination of wireless energy supply, conversion, storage, and delivery to the sensor. Herein, we realized a solar-light-driven power source that consists of a micro fuel cell (μFC) and a photocatalytic micro fuel generator (μFG) integrated on a single microfluidic chip. The μFG produces hydrogen by photocatalytic water splitting under solar light. The hydrogen fuel is then consumed by the μFC to generate electricity. Importantly, the by-product water returns back to the photocatalytic μFG via recirculation loop without losses. Both devices rely on novel phenomena in extended-nano-fluidic channels that ensure ultra-fast proton transport. As a proof of concept, we demonstrate that μFG/μFC source achieves remarkable energy density of ca. 17.2 mWh cm -2 at room temperature. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Thermally induced light-driven microfluidics using a MOEMS-based laser scanner for particle manipulation

    Science.gov (United States)

    Kremer, Matthias P.; Tortschanoff, Andreas

    2014-03-01

    One key challenge in the field of microfluidics and lab-on-a-chip experiments for biological or chemical applications is the remote manipulation of fluids, droplets and particles. These can be volume elements of reactants, particles coated with markers, cells or many others. Light-driven microfluidics is one way of accomplishing this challenge. In our work, we manipulated micrometre sized polystyrene beads in a microfluidic environment by inducing thermal flows. Therefore, the beads were held statically in an unstructured microfluidic chamber, containing a dyed watery solution. Inside this chamber, the beads were moved along arbitrary trajectories on a micrometre scale. The experiments were performed, using a MOEMS (micro-opto-electro-mechanical-systems)-based laser scanner with a variable focal length. This scanner system is integrated in a compact device, which is flexibly applicable to various microscope setups. The device utilizes a novel approach for varying the focal length, using an electrically tunable lens. A quasi statically driven MOEMS mirror is used for beam steering. The combination of a tunable lens and a dual axis micromirror makes the device very compact and robust and is capable of positioning the laser focus at any arbitrary location within a three dimensional working space. Hence, the developed device constitutes a valuable extension to manually executed microfluidic lab-on-chip experiments.

  13. Structure of the light-driven sodium pump KR2 and its implications for optogenetics.

    Science.gov (United States)

    Gushchin, Ivan; Shevchenko, Vitaly; Polovinkin, Vitaly; Borshchevskiy, Valentin; Buslaev, Pavel; Bamberg, Ernst; Gordeliy, Valentin

    2016-04-01

    A key and common process present in organisms from all domains of life is the maintenance of the ion gradient between the inside and the outside of the cell. The gradient is generated by various active transporters, among which are the light-driven ion pumps of the microbial rhodopsin family. Whereas the proton-pumping and anion-pumping rhodopsins have been known for a long time, the cation (sodium) pumps were described only recently. Following the discovery, high-resolution atomic structures of the pump KR2 were determined that revealed the complete ion translocation pathway, including the positions of the characteristic Asn-Asp-Gln (NDQ) triad, the unusual ion uptake cavity acting as a selectivity filter, the unique N-terminal α-helix, capping the ion release cavity, and unexpected flexibility of the retinal-binding pocket. The structures also revealed pentamerization of KR2 and binding of sodium ions at the interface. Finally, on the basis of the structures, potassium-pumping KR2 variants have been designed, making the findings even more important for optogenetic applications. In this Structural Snapshot, we analyse the implications of the structural findings for understanding the sodium translocation mechanism and application of the pump and its mutants in optogenetics. © 2015 FEBS.

  14. Electrogenic steps of light-driven proton transport in ESR, a retinal protein from Exiguobacterium sibiricum.

    Science.gov (United States)

    Siletsky, Sergey A; Mamedov, Mahir D; Lukashev, Evgeniy P; Balashov, Sergei P; Dolgikh, Dmitriy A; Rubin, Andrei B; Kirpichnikov, Mikhail P; Petrovskaya, Lada E

    2016-11-01

    A retinal protein from Exiguobacterium sibiricum (ESR) functions as a light-driven proton pump. Unlike other proton pumps, it contains Lys96 instead of a usual carboxylic residue in the internal proton donor site. Nevertheless, the reprotonation of the Schiff base occurs fast, indicating that Lys96 facilitates proton transfer from the bulk. In this study we examined kinetics of light-induced transmembrane electrical potential difference, ΔΨ, generated in proteoliposomes reconstituted with ESR. We show that total magnitude of ΔΨ is comparable to that produced by bacteriorhodopsin but its kinetic components and their pH dependence are substantially different. The results are in agreement with the earlier finding that proton uptake precedes reprotonation of the Schiff base in ESR, suggesting that Lys96 is unprotonated in the initial state and gains a proton transiently in the photocycle. The electrogenic phases and the photocycle transitions related to proton transfer from the bulk to the Schiff base are pH dependent. At neutral pH, they occur with τ 0.5ms and 4.5ms. At alkaline pH, the fast component ceases and Schiff base reprotonation slows. At pH8.4, a spectrally silent electrogenic component with τ 0.25ms is detected, which can be attributed to proton transfer from the bulk to Lys96. At pH5.1, the amplitude of ΔΨ decreases 10 fold, reflecting a decreased yield and rate of proton transfer, apparently from protonation of the acceptor (Asp85-His57 pair) in the initial state. The features of the photoelectric potential generation correlate with the ESR structure and proposed mechanism of proton transfer. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Nicotinamide riboside kinases display redundancy in mediating nicotinamide mononucleotide and nicotinamide riboside metabolism in skeletal muscle cells.

    Science.gov (United States)

    Fletcher, Rachel S; Ratajczak, Joanna; Doig, Craig L; Oakey, Lucy A; Callingham, Rebecca; Da Silva Xavier, Gabriella; Garten, Antje; Elhassan, Yasir S; Redpath, Philip; Migaud, Marie E; Philp, Andrew; Brenner, Charles; Canto, Carles; Lavery, Gareth G

    2017-08-01

    Augmenting nicotinamide adenine dinucleotide (NAD + ) availability may protect skeletal muscle from age-related metabolic decline. Dietary supplementation of NAD + precursors nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) appear efficacious in elevating muscle NAD + . Here we sought to identify the pathways skeletal muscle cells utilize to synthesize NAD + from NMN and NR and provide insight into mechanisms of muscle metabolic homeostasis. We exploited expression profiling of muscle NAD + biosynthetic pathways, single and double nicotinamide riboside kinase 1/2 (NRK1/2) loss-of-function mice, and pharmacological inhibition of muscle NAD + recycling to evaluate NMN and NR utilization. Skeletal muscle cells primarily rely on nicotinamide phosphoribosyltransferase (NAMPT), NRK1, and NRK2 for salvage biosynthesis of NAD + . NAMPT inhibition depletes muscle NAD + availability and can be rescued by NR and NMN as the preferred precursors for elevating muscle cell NAD + in a pathway that depends on NRK1 and NRK2. Nrk2 knockout mice develop normally and show subtle alterations to their NAD+ metabolome and expression of related genes. NRK1, NRK2, and double KO myotubes revealed redundancy in the NRK dependent metabolism of NR to NAD + . Significantly, these models revealed that NMN supplementation is also dependent upon NRK activity to enhance NAD + availability. These results identify skeletal muscle cells as requiring NAMPT to maintain NAD + availability and reveal that NRK1 and 2 display overlapping function in salvage of exogenous NR and NMN to augment intracellular NAD + availability.

  16. Visible-Light Excitation of a Molecular Motor with an Extended Aromatic Core.

    Science.gov (United States)

    van Leeuwen, Thomas; Pol, Jasper; Roke, Diederik; Wezenberg, Sander J; Feringa, Ben L

    2017-03-17

    Exploring routes to visible-light-driven rotary motors, the possibility of red-shifting the excitation wavelength of molecular motors by extension of the aromatic core is studied. Introducing a dibenzofluorenyl moiety in a standard molecular motor resulted in red-shifting of the absorption spectrum. UV/vis and 1 H NMR spectroscopy showed that these motors could be isomerized with light of wavelengths up to 490 nm and that the structural modification did not impair the anticipated rotary behavior. Extension of the aromatic core is therefore a suitable strategy to apply in pursuit of visible-light-driven molecular motors.

  17. Nicotinamide adenine dinucleotide biosynthesis promotes liver regeneration.

    Science.gov (United States)

    Mukherjee, Sarmistha; Chellappa, Karthikeyani; Moffitt, Andrea; Ndungu, Joan; Dellinger, Ryan W; Davis, James G; Agarwal, Beamon; Baur, Joseph A

    2017-02-01

    The regenerative capacity of the liver is essential for recovery from surgical resection or injuries induced by trauma or toxins. During liver regeneration, the concentration of nicotinamide adenine dinucleotide (NAD) falls, at least in part due to metabolic competition for precursors. To test whether NAD availability restricts the rate of liver regeneration, we supplied nicotinamide riboside (NR), an NAD precursor, in the drinking water of mice subjected to partial hepatectomy. NR increased DNA synthesis, mitotic index, and mass restoration in the regenerating livers. Intriguingly, NR also ameliorated the steatosis that normally accompanies liver regeneration. To distinguish the role of hepatocyte NAD levels from any systemic effects of NR, we generated mice overexpressing nicotinamide phosphoribosyltransferase, a rate-limiting enzyme for NAD synthesis, specifically in the liver. Nicotinamide phosphoribosyltransferase overexpressing mice were mildly hyperglycemic at baseline and, similar to mice treated with NR, exhibited enhanced liver regeneration and reduced steatosis following partial hepatectomy. Conversely, mice lacking nicotinamide phosphoribosyltransferase in hepatocytes exhibited impaired regenerative capacity that was completely rescued by administering NR. NAD availability is limiting during liver regeneration, and supplementation with precursors such as NR may be therapeutic in settings of acute liver injury. (Hepatology 2017;65:616-630). © 2016 by the American Association for the Study of Liver Diseases.

  18. Anti-Trypanosoma cruzi activity of nicotinamide.

    Science.gov (United States)

    Soares, Milena B P; Silva, Cinara V; Bastos, Tanira M; Guimarães, Elisalva T; Figueira, Claudio P; Smirlis, Despina; Azevedo, Walter F

    2012-05-01

    Inhibition of Trypanosoma brucei and Leishmania spp. sirtuins has shown promising antiparasitic activity, indicating that these enzymes may be used as targets for drug discovery against trypanosomatid infections. In the present work we carried out a virtual screening focused on the C pocket of Sir2 from Trypanosoma cruzi. Using this approach, the best ligand found was nicotinamide. In vitro tests confirmed the anti-T. cruzi activity of nicotinamide on epimastigote and trypomastigote forms. Moreover, treatment of T. cruzi-infected macrophages with nicotinamide caused a significant reduction in the number of amastigotes. In addition, alterations in the mitochondria and an increase in the vacuolization in the cytoplasm were observed in epimastigotes treated with nicotinamide. Analysis of the complex of Sir2 and nicotinamide revealed the details of the possible ligand-target interaction. Our data reveal a potential use of TcSir2 as a target for anti-T. cruzi drug discovery. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Graphene-Based Polymer Bilayers with Superior Light-Driven Properties for Remote Construction of 3D Structures.

    Science.gov (United States)

    Tang, Zhenhua; Gao, Ziwei; Jia, Shuhai; Wang, Fei; Wang, Yonglin

    2017-05-01

    3D structure assembly in advanced functional materials is important for many areas of technology. Here, a new strategy exploits IR light-driven bilayer polymeric composites for autonomic origami assembly of 3D structures. The bilayer sheet comprises a passive layer of poly(dimethylsiloxane) (PDMS) and an active layer comprising reduced graphene oxides (RGOs), thermally expanding microspheres (TEMs), and PDMS. The corresponding fabrication method is versatile and simple. Owing to the large volume expansion of the TEMs, the two layers exhibit large differences in their coefficients of thermal expansion. The RGO-TEM-PDMS/PDMS bilayers can deflect toward the PDMS side upon IR irradiation via the cooperative effect of the photothermal effect of the RGOs and the expansion of the TEMs, and exhibit excellent light-driven, a large bending deformation, and rapid responsive properties. The proposed RGO-TEM-PDMS/PDMS composites with excellent light-driven bending properties are demonstrated as active hinges for building 3D geometries such as bidirectionally folded columns, boxes, pyramids, and cars. The folding angle (ranging from 0° to 180°) is well-controlled by tuning the active hinge length. Furthermore, the folded 3D architectures can permanently preserve the deformed shape without energy supply. The presented approach has potential in biomedical devices, aerospace applications, microfluidic devices, and 4D printing.

  20. Light-driven increase in carbon yield is linked to maintenance in the proteorhodopsin-containing Photobacterium angustum S14

    Directory of Open Access Journals (Sweden)

    Alicia eCourties

    2015-07-01

    Full Text Available A type of photoheterotrophic bacteria contain a transmembrane light-driven proton pump called proteorhodopsins (PRs. Due to the prevalence of these organisms in the upper water column of the World’s Ocean, and their potential for light driven ATP generation, they have been suggested to significantly influence energy and matter flows in the biosphere. To date, evidence for the significance of the light-driven metabolism of PR-containing prokaryotes has been obtained by comparing growth in batch culture, under light versus dark conditions, and it appears that responses to light are linked to unfavorable conditions, which so far have not been well parameterized. We studied light responses to carbon yields of the PR-containing Photobacterium angustum S14 using continuous culture conditions and light-dark cycles. We observed significant effects of light-dark cycles compared to dark controls, as well as significant differences between samples after 12 h illumination versus 12 h darkness. However these effects were only observed under higher cell counts and lower pH associated with higher substrate concentrations. Under these substrate levels Pirt’s maintenance coefficient was higher when compared to lower substrate dark controls, and decreased under light-dark cycles. It appears that light responses by Photobacterium angustum S14 are induced by the energetic status of the cells rather than by low substrate concentrations.

  1. Hydrogen bonding interactions in nicotinamide Ionic Liquids: A comparative spectroscopic and DFT studies

    Science.gov (United States)

    Shukla, Madhulata

    2017-03-01

    Being biodegradable in nature nicotinamide based Ionic Liquids (ILs) are gaining much attention now a day. Nicotinamide iodide (i.e 1-methyl-3ethoxy carbonyl pyridinium iodide (mNicI)) and 1-methyl-3ethoxy carbonyl pyridinium trifilimide (mNicNTf2) new ILs has been synthesized and has been characterized using different spectroscopic techniques like NMR, UV visible and infrared spectroscopy. Theoretical studies have been performed on several nicotinamide ILs. Geometry and spectral features were further characterized by Density Functional Theory (DFT) calculation. NBO charge distribution and electrostatic potential diagram presents in depth knowledge about interactions between cation and anion. A comparative theoretical study between mNicI and its other analogues i. e 1-methyl-3 ethoxy carbonyl pyridinium chloride and bromide i. e mNicCl and mNicBr has also been performed. Csbnd H⋯X hydrogen bonding along with C⋯X interaction has been reported for the first time for the nicotinamide based ILs. C2sbnd H stretching frequency shifts to higher wavenumber with change to a lesser electronegative anion. mNicCl and mNicBr are expected to be solid in nature with the evidence from the red shift in stretching frequency as compared to mNicI. TD-DFT calculation of mNicI proved that pale yellow color of liquid is due to inherent transition from anion to cation.

  2. 21 CFR 172.315 - Nicotinamide-ascorbic acid complex.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nicotinamide-ascorbic acid complex. 172.315 Section... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.315 Nicotinamide-ascorbic acid complex. Nicotinamide-ascorbic acid complex may be safely used in accordance with the following prescribed conditions...

  3. Nicotinamide ribosyl uptake mutants in Haemophilus influenzae.

    Science.gov (United States)

    Herbert, Mark; Sauer, Elizabeta; Smethurst, Graeme; Kraiss, Anita; Hilpert, Anna-Karina; Reidl, Joachim

    2003-09-01

    The gene for the nicotinamide riboside (NR) transporter (pnuC) was identified in Haemophilus influenzae. A pnuC mutant had only residual NR uptake and could survive in vitro with high concentrations of NR, but could not survive in vivo. PnuC may represent a target for the development of inhibitors for preventing H. influenzae disease.

  4. [Chronic nicotinamide overload and type 2 diabetes].

    Science.gov (United States)

    Zhou, Shi-Sheng; Li, Da; Zhou, Yi-Ming; Sun, Wu-Ping; Liu, Xing-Xing; Lun, Yong-Zhi

    2010-02-25

    Type 2 diabetes is a major global health problem. It is generally accepted that type 2 diabetes is the result of gene-environmental interaction. However, the mechanism underlying the interaction is unclear. Diet change is known to play an important role in type 2 diabetes. The fact that the global high prevalence of type 2 diabetes has occurred following the spread of food fortification worldwide suggests a possible involvement of excess niacin intake. Our recent study found that nicotinamide overload and low nicotinamide detoxification may induce oxidative stress associated with insulin resistance. Based on the relevant facts, this review briefly summarized the relationship between the prevalence of type 2 diabetes and the nicotinamide metabolism changes induced by excess niacin intake, aldehyde oxidase inhibitors, liver diseases and functional defects of skin. We speculate that the gene-environmental interaction in type 2 diabetes may be a reflection of the outcome of the association of chronic nicotinamide overload-induced toxicity and the relatively low detoxification/excretion capacity of the body. Reducing the content of niacin in foods may be a promising strategy for the control of type 2 diabetes.

  5. DESIGN, SYNTHESIS AND STUDY OF MULTI-COMPONENT AND INTEGRATED SYSTEMS FOR LIGHT-DRIVEN HYDROGEN GENERATION

    Energy Technology Data Exchange (ETDEWEB)

    Professor Richard Eisenberg

    2012-07-18

    The research focussed on fundamental problems in the conversion of light to stored chemical energy. Specifically, work was completed on the design, synthesis and study of multi-component super- and supramolecular systems for photoinduced charge separation, one of the key steps in artificial photosynthesis, and on the use of these and related systems for the photochemical generation of H2 from water. At the center of these systems are chromophores comprised of square planar coordinated Pt(II) ions with arylacetylide and either diimine or terpyridyl ligands. Previous work had shown that the chromophores are photoluminescent in fluid solution with long-lived metal-to-ligand charge transfer (3MLCT) excited states that are necessarily directional. An advance which set the stage for a number of proposed studies was the light-driven production of hydrogen from water using a Pt(terpyridyl)(arylacetylide)+ chromophore and a sacrificial electron donor. The reaction is catalytic and appears to rival previously reported ruthenium bipyridyl systems in terms of H2 production. Variation of system components and mechanistic studies were conducted to understand better the individual steps in the overall process and how to improve its efficiency. Success with light driven H2 generation was employed as a key probe as new systems were constructed consisting of triads for photoinduced charge separation placed in close proximity to the H2 generating catalyst - a Pt colloid - through direct linkage or supramolecular interactions with the polymer used to stabilize the colloid. In order to prepare new donor-chromophore-acceptor (D-C-A) triads and associated D-C and C-A dyads, new ligands were synthesized having functional groups for different coupling reactions such as simple amide formation and Pd-catalyzed coupling. In these systems, the donor was attached to the arylacetylide ligands and the acceptor was linked to the diimine or terpyridyl chelate. Research under the contract proved

  6. Engineering a Chemical Switch into the Light-driven Proton Pump Proteorhodopsin by Cysteine Mutagenesis and Thiol Modification.

    Science.gov (United States)

    Harder, Daniel; Hirschi, Stephan; Ucurum, Zöhre; Goers, Roland; Meier, Wolfgang; Müller, Daniel J; Fotiadis, Dimitrios

    2016-07-25

    For applications in synthetic biology, for example, the bottom-up assembly of biomolecular nanofactories, modules of specific and controllable functionalities are essential. Of fundamental importance in such systems are energizing modules, which are able to establish an electrochemical gradient across a vesicular membrane as an energy source for powering other modules. Light-driven proton pumps like proteorhodopsin (PR) are excellent candidates for efficient energy conversion. We have extended the versatility of PR by implementing an on/off switch based on reversible chemical modification of a site-specifically introduced cysteine residue. The position of this cysteine residue in PR was identified by structure-based cysteine mutagenesis combined with a proton-pumping assay using E. coli cells overexpressing PR and PR proteoliposomes. The identified PR mutant represents the first light-driven proton pump that can be chemically switched on/off depending on the requirements of the molecular system. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Dye-Enhanced Self-Electrophoretic Propulsion of Light-Driven TiO2-Au Janus Micromotors

    Science.gov (United States)

    Wu, Yefei; Dong, Renfeng; Zhang, Qilu; Ren, Biye

    2017-07-01

    Light-driven synthetic micro-/nanomotors have attracted considerable attention in recent years due to their unique performances and potential applications. We herein demonstrate the dye-enhanced self-electrophoretic propulsion of light-driven TiO2-Au Janus micromotors in aqueous dye solutions. Compared to the velocities of these micromotors in pure water, 1.7, 1.5, and 1.4 times accelerated motions were observed for them in aqueous solutions of methyl blue (10-5 g L-1), cresol red (10-4 g L-1), and methyl orange (10-4 g L-1), respectively. We determined that the micromotor speed changes depending on the type of dyes, due to variations in their photodegradation rates. In addition, following the deposition of a paramagnetic Ni layer between the Au and TiO2 layers, the micromotor can be precisely navigated under an external magnetic field. Such magnetic micromotors not only facilitate the recycling of micromotors, but also allow reusability in the context of dye detection and degradation. In general, such photocatalytic micro-/nanomotors provide considerable potential for the rapid detection and "on-the-fly" degradation of dye pollutants in aqueous environments.

  8. Is sensitization with nicotinamide and carbogen dependent on nicotinamide concentration at the time of irradiation?

    Science.gov (United States)

    Rojas, A; Stratford, M R L; Bentzen, S M; Denekamp, J

    2004-07-01

    To determine whether tumour radiosensitization and the therapeutic benefit of administering carbogen with nicotinamide depend upon irradiating at the time of peak drug concentration. Local tumour control of CaNT tumours in CBA mice and acute skin reactions in albino WHT mice were assessed after treatment with 10 X-ray fractions in air, carbogen alone or combined with 0.1, 0.2 or 0.5 mg g(-1) nicotinamide, injected 15, 30 or 60 min before irradiation. Plasma and tumour drug pharmacokinetics were performed. Nicotinamide was rapidly taken up into tumours; a six- and threefold higher concentration was obtained with 0.5 mg g(-1) compared with 0.1 and 0.2 mg g(-1), respectively. Tumour, but not skin, radiosensitization increased as the dose of nicotinamide increased (p = 0.03), but at each dose level there was no significant difference in radiosensitivity when irradiations were done at or after the time of peak concentration. An almost eightfold increase in plasma levels increased tumour enhancement ratios from 1.74 to 1.92 (p skin radiosensitivity was independent of time of nicotinamide administration. Higher drug concentrations were not mirrored by proportionally higher enhancement ratios. Lower plasma levels than previously suggested significantly enhanced tumour radiosensitivity relative to carbogen alone. The clinical implications of these findings are discussed.

  9. Crystal Structure of Human Nicotinamide Riboside Kinase

    Energy Technology Data Exchange (ETDEWEB)

    Khan,J.; Xiang, S.; Tong, L.

    2007-01-01

    Nicotinamide riboside kinase (NRK) has an important role in the biosynthesis of NAD{sup +} as well as the activation of tiazofurin and other NR analogs for anticancer therapy. NRK belongs to the deoxynucleoside kinase and nucleoside monophosphate (NMP) kinase superfamily, although the degree of sequence conservation is very low. We report here the crystal structures of human NRK1 in a binary complex with the reaction product nicotinamide mononucleotide (NMN) at 1.5 {angstrom} resolution and in a ternary complex with ADP and tiazofurin at 2.7 {angstrom} resolution. The active site is located in a groove between the central parallel {beta} sheet core and the LID and NMP-binding domains. The hydroxyl groups on the ribose of NR are recognized by Asp56 and Arg129, and Asp36 is the general base of the enzyme. Mutation of residues in the active site can abolish the catalytic activity of the enzyme, confirming the structural observations.

  10. Crystal structure of human nicotinamide riboside kinase.

    Science.gov (United States)

    Khan, Javed A; Xiang, Song; Tong, Liang

    2007-08-01

    Nicotinamide riboside kinase (NRK) has an important role in the biosynthesis of NAD(+) as well as the activation of tiazofurin and other NR analogs for anticancer therapy. NRK belongs to the deoxynucleoside kinase and nucleoside monophosphate (NMP) kinase superfamily, although the degree of sequence conservation is very low. We report here the crystal structures of human NRK1 in a binary complex with the reaction product nicotinamide mononucleotide (NMN) at 1.5 A resolution and in a ternary complex with ADP and tiazofurin at 2.7 A resolution. The active site is located in a groove between the central parallel beta sheet core and the LID and NMP-binding domains. The hydroxyl groups on the ribose of NR are recognized by Asp56 and Arg129, and Asp36 is the general base of the enzyme. Mutation of residues in the active site can abolish the catalytic activity of the enzyme, confirming the structural observations.

  11. European Nicotinamide Diabetes Intervention Trial (ENDIT)

    DEFF Research Database (Denmark)

    Gale, E A M; Bingley, P J; Emmett, C L

    2004-01-01

    Juvenile Diabetes Federation (JDF) units or more, and a non-diabetic oral glucose tolerance test. Participants were recruited from 18 European countries, Canada, and the USA, and were randomly allocated oral modified release nicotinamide (1.2 g/m2) or placebo for 5 years. Random allocation was done...... with a pseudorandom number generator and we used size balanced blocks of four and stratified by age and national group. Primary outcome was development of diabetes, as defined by WHO criteria. Analysis was done on an intention-to-treat basis. FINDINGS: There was no difference in the development of diabetes between...... secretion. INTERPRETATION: Large-scale controlled trials of interventions designed to prevent the onset of type 1 diabetes are feasible, but nicotinamide was ineffective at the dose we used....

  12. Role of Nicotinamide in DNA Damage, Mutagenesis, and DNA Repair

    Directory of Open Access Journals (Sweden)

    Devita Surjana

    2010-01-01

    Full Text Available Nicotinamide is a water-soluble amide form of niacin (nicotinic acid or vitamin B3. Both niacin and nicotinamide are widely available in plant and animal foods, and niacin can also be endogenously synthesized in the liver from dietary tryptophan. Nicotinamide is also commercially available in vitamin supplements and in a range of cosmetic, hair, and skin preparations. Nicotinamide is the primary precursor of nicotinamide adenine dinucleotide (NAD+, an essential coenzyme in ATP production and the sole substrate of the nuclear enzyme poly-ADP-ribose polymerase-1 (PARP-1. Numerous in vitro and in vivo studies have clearly shown that PARP-1 and NAD+ status influence cellular responses to genotoxicity which can lead to mutagenesis and cancer formation. This paper will examine the role of nicotinamide in the protection from carcinogenesis, DNA repair, and maintenance of genomic stability.

  13. In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae.

    OpenAIRE

    Godek, C P; Cynamon, M H

    1990-01-01

    Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs...

  14. Moisturizing effects of topical nicotinamide on atopic dry skin.

    Science.gov (United States)

    Soma, Yoshinao; Kashima, Masato; Imaizumi, Akiko; Takahama, Hideto; Kawakami, Tamihiro; Mizoguchi, Masako

    2005-03-01

    Certain moisturizers can improve skin barrier function in atopic dermatitis. The effect of topical nicotinamide on atopic dry skin is unknown. We examined the effect of topical nicotinamide on atopic dry skin and compared the results with the effect of white petrolatum in a left-right comparison study. Twenty-eight patients with atopic dermatitis, with symmetrical lesions of dry skin on both forearms, were enrolled, and were instructed to apply nicotinamide cream containing 2% nicotinamide on the left forearm and white petrolatum on the right forearm, twice daily over a 4- or 8-week treatment period. Transepidermal water loss and stratum corneum hydration were measured by instrumental devices. The amount of the stratum corneum exfoliated by tape stripping (desquamation index) was determined by an image analyzer. Nicotinamide significantly decreased transepidermal water loss, but white petrolatum did not show any significant effect. Both nicotinamide and white petrolatum increased stratum corneum hydration, but nicotinamide was significantly more effective than white petrolatum. The desquamation index was positively correlated with stratum corneum hydration at baseline and gradually increased in the nicotinamide group, but not in the white petrolatum group. Nicotinamide cream is a more effective moisturizer than white petrolatum on atopic dry skin, and may be used as a treatment adjunct in atopic dermatitis.

  15. Oral nicotinamide and actinic keratosis: a supplement success story.

    Science.gov (United States)

    Kim, Burcu; Halliday, Gary M; Damian, Diona L

    2015-01-01

    Nicotinamide has shown potential as a safe and effective intervention for the prevention of malignant and premalignant skin lesions. Recent studies have shown that nicotinamide, in both oral and topical forms, is able to prevent ultraviolet-induced immunosuppression in humans [1,2,3] and mice [4,5]. Immunosuppression is a known factor for the progression of premalignant lesions, such as actinic keratosis [6]. Murine studies have shown that nicotinamide is also able to protect against photocarcinogenesis [4,5]. Preliminary human studies suggest that nicotinamide may help prevent skin cancers and enhance the regression of actinic keratoses. © 2015 S. Karger AG, Basel.

  16. Novel RGO/α-FeOOH supported catalyst for Fenton oxidation of phenol at a wide pH range using solar-light-driven irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying, E-mail: yingwang@bnu.edu.cn [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China); Fang, Jiasheng, E-mail: fangfangcanfly@163.com [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China); School of Chemistry and Chemical Engineering, Southeast University, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Nanjing 211189 (China); Crittenden, John C., E-mail: John.Crittenden@ce.gatech.edu [School of Civil and Environmental Engineering and the Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta, GA 30332-0595 (United States); Shen, Chanchan [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China)

    2017-05-05

    Graphical abstract: Schematic of the preparation of RF supported catalysts and the reaction mechanism for SLD Fenton catalytic degradation of aqueous phenol. - Highlights: • Novel SLD Fenton catalyst was synthesized via in-situ induced self-assembly process. • RGO improved light-harvesting capacity and enhanced electro-transport performance. • Visible light irradiation accelerated reaction and extended operating pHs (4.0–8.0). • H{sub 2}O{sub 2} reduction and H{sub 2}O oxidation yielded ·OH in Fe{sup Ⅱ}/Fe{sup Ⅲ} and Fe{sup Ⅲ}/Fe{sup Ⅳ} cycling process. - Abstract: A novel solar-light-driven (SLD) Fenton catalyst was developed by reducing the ferrous-ion onto graphene oxide (GO) and forming reduced graphene oxide/α-FeOOH composites (RF) via in-situ induced self-assembly process. The RF was supported on several mesoporous supports (i.e., Al-MCM-41, MCM-41 and γ-Al{sub 2}O{sub 3}). The activity, stability and energy use for phenol oxidation were systematically studied for a wide pH range. Furthermore, the catalytic mechanism at acid and alkaline aqueous conditions was also elucidated. The results showed that Fe(II) was reduced onto GO nanosheets and α-FeOOH crystals were formed during the self-assembly process. Compared with Fenton reaction without SLD irradiation, the visible light irradiation not only dramatically accelerated the rate of Fenton-based reactions, but also extended the operating pH for the Fenton reaction (from 4.0 to 8.0). The phenol oxidation on RF supported catalysts was fitting well with the pseudo-first-order kinetics, and needed low initiating energy, insensitive to the reacting temperature changes (273–318 K). The Al-MCM-41 supported RF was a more highly energy-efficient catalyst with the prominent catalytic activity at wide operating pHs. During the reaction, ·OH radicals were generated by the SLD irradiation from H{sub 2}O{sub 2} reduction and H{sub 2}O oxidation in the Fe{sup Ⅱ}/Fe{sup Ⅲ} and Fe{sup Ⅲ}/Fe{sup

  17. Light-driven dinitrogen reduction catalyzed by a CdS:nitrogenase MoFe protein biohybrid

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K. A.; Harris, D. F.; Wilker, M. B.; Rasmussen, A.; Khadka, N.; Hamby, H.; Keable, S.; Dukovic, G.; Peters, J. W.; Seefeldt, L. C.; King, P. W.

    2016-04-21

    The splitting of dinitrogen (N2) and reduction to ammonia (NH3) is a kinetically complex and energetically challenging multistep reaction. In the Haber-Bosch process, N2 reduction is accomplished at high temperature and pressure, whereas N2 fixation by the enzyme nitrogenase occurs under ambient conditions using chemical energy from adenosine 5'-triphosphate (ATP) hydrolysis. We show that cadmium sulfide (CdS) nanocrystals can be used to photosensitize the nitrogenase molybdenum-iron (MoFe) protein, where light harvesting replaces ATP hydrolysis to drive the enzymatic reduction of N2 into NH3. The turnover rate was 75 per minute, 63% of the ATP-coupled reaction rate for the nitrogenase complex under optimal conditions. Inhibitors of nitrogenase (i.e., acetylene, carbon monoxide, and dihydrogen) suppressed N2 reduction. The CdS:MoFe protein biohybrids provide a photochemical model for achieving light-driven N2 reduction to NH3.

  18. A light-driven three-dimensional plasmonic nanosystem that translates molecular motion into reversible chiroptical function

    Science.gov (United States)

    Kuzyk, Anton; Yang, Yangyang; Duan, Xiaoyang; Stoll, Simon; Govorov, Alexander O.; Sugiyama, Hiroshi; Endo, Masayuki; Liu, Na

    2016-02-01

    Nature has developed striking light-powered proteins such as bacteriorhodopsin, which can convert light energy into conformational changes for biological functions. Such natural machines are a great source of inspiration for creation of their synthetic analogues. However, synthetic molecular machines typically operate at the nanometre scale or below. Translating controlled operation of individual molecular machines to a larger dimension, for example, to 10-100 nm, which features many practical applications, is highly important but remains challenging. Here we demonstrate a light-driven plasmonic nanosystem that can amplify the molecular motion of azobenzene through the host nanostructure and consequently translate it into reversible chiroptical function with large amplitude modulation. Light is exploited as both energy source and information probe. Our plasmonic nanosystem bears unique features of optical addressability, reversibility and modulability, which are crucial for developing all-optical molecular devices with desired functionalities.

  19. Non-image-forming light driven functions are preserved in a mouse model of autosomal dominant optic atrophy.

    Directory of Open Access Journals (Sweden)

    Georgia Perganta

    Full Text Available Autosomal dominant optic atrophy (ADOA is a slowly progressive optic neuropathy that has been associated with mutations of the OPA1 gene. In patients, the disease primarily affects the retinal ganglion cells (RGCs and causes optic nerve atrophy and visual loss. A subset of RGCs are intrinsically photosensitive, express the photopigment melanopsin and drive non-image-forming (NIF visual functions including light driven circadian and sleep behaviours and the pupil light reflex. Given the RGC pathology in ADOA, disruption of NIF functions might be predicted. Interestingly in ADOA patients the pupil light reflex was preserved, although NIF behavioural outputs were not examined. The B6; C3-Opa1(Q285STOP mouse model of ADOA displays optic nerve abnormalities, RGC dendropathy and functional visual disruption. We performed a comprehensive assessment of light driven NIF functions in this mouse model using wheel running activity monitoring, videotracking and pupillometry. Opa1 mutant mice entrained their activity rhythm to the external light/dark cycle, suppressed their activity in response to acute light exposure at night, generated circadian phase shift responses to 480 nm and 525 nm pulses, demonstrated immobility-defined sleep induction following exposure to a brief light pulse at night and exhibited an intensity dependent pupil light reflex. There were no significant differences in any parameter tested relative to wildtype littermate controls. Furthermore, there was no significant difference in the number of melanopsin-expressing RGCs, cell morphology or melanopsin transcript levels between genotypes. Taken together, these findings suggest the preservation of NIF functions in Opa1 mutants. The results provide support to growing evidence that the melanopsin-expressing RGCs are protected in mitochondrial optic neuropathies.

  20. NRK1 controls nicotinamide mononucleotide and nicotinamide riboside metabolism in mammalian cells.

    Science.gov (United States)

    Ratajczak, Joanna; Joffraud, Magali; Trammell, Samuel A J; Ras, Rosa; Canela, Núria; Boutant, Marie; Kulkarni, Sameer S; Rodrigues, Marcelo; Redpath, Philip; Migaud, Marie E; Auwerx, Johan; Yanes, Oscar; Brenner, Charles; Cantó, Carles

    2016-10-11

    NAD + is a vital redox cofactor and a substrate required for activity of various enzyme families, including sirtuins and poly(ADP-ribose) polymerases. Supplementation with NAD + precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), protects against metabolic disease, neurodegenerative disorders and age-related physiological decline in mammals. Here we show that nicotinamide riboside kinase 1 (NRK1) is necessary and rate-limiting for the use of exogenous NR and NMN for NAD + synthesis. Using genetic gain- and loss-of-function models, we further demonstrate that the role of NRK1 in driving NAD + synthesis from other NAD + precursors, such as nicotinamide or nicotinic acid, is dispensable. Using stable isotope-labelled compounds, we confirm NMN is metabolized extracellularly to NR that is then taken up by the cell and converted into NAD + . Our results indicate that mammalian cells require conversion of extracellular NMN to NR for cellular uptake and NAD + synthesis, explaining the overlapping metabolic effects observed with the two compounds.

  1. In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae.

    Science.gov (United States)

    Godek, C P; Cynamon, M H

    1990-08-01

    Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs. These compounds and several other nicotinamide riboside analogs were evaluated for their ability to support the growth of H. influenzae and for their ability to block the uptake of [carbonyl-14C]nicotinamide riboside by H. influenzae. 3-Aminopyridine riboside blocked the uptake of [carbonyl-14C]nicotinamide riboside and inhibited the growth of H. influenzae when NAD, nicotinamide mononucleotide, or nicotinamide riboside served as the V factor. The antibacterial activity of 3-aminopyridine riboside was found to be specific for H. influenzae but had no effect on the growth of Staphylococcus aureus or Escherichia coli. In additional experiments by reversed-phase high-performance liquid chromatography, it was determined that whole cells of H. influenzae degrade 3-aminopyridine adenine dinucleotide to 3-aminopyridine riboside, which is then internalized. Inside the cell, 3-aminopyridine riboside has the ability to interfere with the growth of H. influenzae by an undetermined mechanism.

  2. BULLOUS PEMPHIGOID SUCCESSFULLY CONTROLLED BY TETRACYCLINE AND NICOTINAMIDE

    NARCIS (Netherlands)

    KOLBACH, DN; REMME, JJ; BOS, WH; JONKMAN, MF; DEJONG, MCJM; PAS, HH; VANDERMEER, JB

    In 1986, Berk and Lorincz reported the efficacy of tetracycline and nicotinamide in the treatment of bullous pemphigoid (BP). In the present study of seven patients with BP, we found that a regimen of 2 g tetracycline combined with 2 g nicotinamide daily was effective in clearing the skin lesions.

  3. Near infrared light-driven water oxidation in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer

    NARCIS (Netherlands)

    Liu, X.; Chen, H.C.; Kong, X.; Zhang, Y.; Tu, L.; Chang, Y.; Wu, F.; Wang, T.; Reek, J.N.H.; Brouwer, A.M.; Zhang, H.

    2015-01-01

    We provide the first demonstration of a near infrared light driven water oxidation reaction in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer. One very attractive advantage of this system is that using NIR light irradiation does not cause significant

  4. A Quantitative Analysis of Light-Driven Charge Transfer Processes Using Voronoi Partitioning of Time Dependent DFT-Derived Electron Densities

    NARCIS (Netherlands)

    Rombouts, J.A.; Ehlers, A.W.; Lammertsma, K.

    2017-01-01

    An analytical method is presented that provides quantitative insight into light-driven electron density rearrangement using the output of standard time-dependent density functional theory (TD-DFT) computations on molecular compounds. Using final and initial electron densities for photochemical

  5. FTIR spectroscopy of a light-driven compatible sodium ion-proton pumping rhodopsin at 77 K.

    Science.gov (United States)

    Ono, Hikaru; Inoue, Keiichi; Abe-Yoshizumi, Rei; Kandori, Hideki

    2014-05-08

    Krokinobacter eikastus rhodopsin 2 (KR2) is a light-driven sodium ion pump that was discovered in marine bacteria. Although KR2 is able to pump lithium ions similarly, it is converted into a proton pump in potassium chloride or salts of larger cations. In this paper, we applied light-induced difference Fourier-transform infrared (FTIR) spectroscopy to KR2, a compatible sodium ion-proton pump, at 77 K. The first structural study of the functional cycle showed that the structure and structural changes in the primary processes of KR2 are common to all microbial rhodopsins. The red shifted K formation (KR2K) was accompanied by retinal photoisomerization from an all-trans to a 13-cis form, resulting in a distorted retinal chromophore. The observed hydrogen out-of-plane vibrations were H/D exchangeable, indicating that the chromophore distortion by retinal isomerization is located near the Schiff base region in KR2. This tendency was also the case for bacteriorhodopsin and halorhodopsin but not the case for sensory rhodopsin I and II. Therefore, ion pumps such as proton, chloride, and sodium pumps exhibit local structural perturbations of retinal at the Schiff base moiety, while photosensors show more extended structural perturbations of retinal. The retinal Schiff base of KR2 forms a hydrogen bond that is stronger than in BR. KR2 possesses more protein-bound water molecules than other microbial rhodopsins and contains strongly hydrogen-bonded water (O-D stretch at 2333 cm(-1) in D2O). The light-induced difference FTIR spectra at 77 K were identical between the two states functioning as light-driven sodium ion and proton pumps, indicating that the structural changes in the primary processes are identical between different ion pump functions in KR2. In other words, it is unknown which ions are transported by molecules when they absorb photons and photoisomerize. It is likely that the relaxation processes from the K state lead to an alternative function, namely a sodium

  6. Visible-light driven Photoelectrochemical Immunosensor Based on SnS2@mpg-C3N4 for Detection of Prostate Specific Antigen

    OpenAIRE

    Zhang, Yifeng; Liu, Yixin; Li, Rongxia; Saddam Khan, Malik; Gao, Picheng; Zhang, Yong; Wei, Qin

    2017-01-01

    Herein, a novel label-free photoelectrochemical (PEC) immunosensor based on SnS2@mpg-C3N4 nanocomposite is fabricated for the detection of prostate specific antigen (PSA) in human serum. Firstly, mesoporous graphite-like carbon nitride (mpg-C3N4) with carboxyl groups is synthesized successfully which possesses high specific surface area and large pore volume. Then, SnS2 as a typical n-type semiconductor with weak photoelectric conversion capability is successfully loaded on carboxylated mpg-C...

  7. Characterization, Degradation, and Reaction Pathways of Indoor Toluene over Visible-light-driven S, Zn Co-doped TiO2

    Science.gov (United States)

    Chu, H.; Lin, Y. H.; Lin, C. Y.

    2017-01-01

    Sulfur and Zinc co-doped TiO2 prepared by a sol-gel method to degrade toluene under a fluorescent lamp was investigated. The results indicate that S,Zn co-doped TiO2 photocatalysts are mainly nano-size with an anatase phase structure. The degradation reactions of toluene were performed under various operation conditions. The results show that the toluene conversion increases with increasing toluene concentration and decreasing relative humidity. Based on the results of activity test, S0.05Zn0.001/TiO2 was chosen for further studies. The main oxidation products of toluene photodegradation are CO2, H2O, benzyl alcohol, acetone, butadiene and acetic acid. Two possible mechanisms have been developed for photodegradation of toluene in a dry and a humid environment.

  8. Polystyrene Nanofiber Materials for Visible-Light-Driven Dual Antibacterial Action via Simultaneous Photogeneration of NO and O2((1)Deltag)

    Czech Academy of Sciences Publication Activity Database

    Dolanský, Jiří; Henke, P.; Kubát, Pavel; Fraix, A.; Sortino, S.; Mosinger, Jiří

    2015-01-01

    Roč. 7, č. 41 (2015), s. 22980-22989 ISSN 1944-8244 R&D Projects: GA ČR GA13-12496S Institutional support: RVO:61388980 ; RVO:61388955 Keywords : nanofiber * singlet oxygen * nitric oxide * photogeneration Subject RIV: CA - Inorganic Chemistry; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 7.145, year: 2015

  9. Fabricaion of improved novel p–n junction BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} nanocomposite for visible light driven photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Weicheng [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Jianzhang, E-mail: fangjzh@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China); Zhu, Ximiao [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Fang, Zhanqiang [School of Chemistry and Environment, South China Normal University, Guangzhou 510006, Guangdong (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China); Cen, Chaoping [The Key Laboratory of Water and Air Pollution Control of Guangdong Province, South China Institute of Environmental Sciences, Guangzhou 510655 (China)

    2015-12-15

    Graphical abstract: - Highlights: • A p–n heterojunction photocatalyst BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} was prepared by hydrothermal method. • 4% BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} with maximal photocatalytic degradation efficiency (RhB) of 99.9%. • A specific degradation routes of RhB was illustrated. • The photocatalytic mechanism is discussed according to p–n junction principles. • • O{sub 2}{sup −} and h+ are the main reactive species for the degradation of RhB. - Abstract: A series of novel p−n junction photocatalysts BiOI/Bi{sub 2}Sn{sub 2}O{sub 7} (BiOI/BSO) were successfully fabricated via a facile hydrothermal method. The phase structures, morphologies and optical properties of the as-prepared samples were studied by XRD, TEM, HRTEM, BET, XPS, UV–vis DRS and photoluminescence (PL) spectroscopy. The results showed that BiOI/BSO heteronanostructures displayed much higher photocatalytic activity than pure BSO and BiOI for the degradation of rhodamine B (RhB). The best photocatalytic activity of BiOI/BSO with almost 99.9% RhB degradation situated at molar percentage ratio of 4% after 6 h irradiation. The enhanced photocatalytic performance of BiOI/BSO could be mainly attributed to the formation of the heterojunction between p-BiOI and n-BSO, which effectively restrains the recombination of photoinduced electron–hole pairs. Moreover, the study of radical scavengers affirmed that h{sup +} and • O{sub 2}{sup −} were the primary reactive species for the degradation of RhB.

  10. Fabrication of magnetic Fe@ZnO0.6S0.4 nanocomposite for visible-light-driven photocatalytic inactivation of Escherichia coli

    Science.gov (United States)

    Peng, Ziling; Wu, Dan; Wang, Wei; Tan, Fatang; Ng, Tsz Wai; Chen, Jianguo; Qiao, Xueliang; Wong, Po Keung

    2017-02-01

    Bacterial inactivation by magnetic photocatalysts has now received growing interests due to the easy separation for recycle and reuse of photocatalysts. In this study, magnetic Fe@ZnO0.6S0.4 photocatalyst was prepared by a facile two-step precipitation method. Multiple techniques such as X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffused reflectance spectra (UV-vis DRS) and vibrating sample magnetometer (VSM) were employed to characterize the structure, morphology and physicochemical properties of the photocatalyst. The as-obtained Fe@ZnO0.6S0.4 possessing magnetic property was easily collected from the reaction system by a magnet. Under white light-emitting-diode (LED) lamp irradiation, Fe@ZnO0.6S0.4 nanocomposite could completely inactivate 7-log of Escherichia coli K-12 within 5 h. More importantly, almost no decrease of photocatalytic efficiency in bacterial inactivation was observed even after five consecutive cycles, demonstrating Fe@ZnO0.6S0.4 exhibited good stability for reuse. The low released rate of Fe2+/Fe3+ and Zn2+ from Fe@ZnO0.6S0.4 composite further indicated the photocatalyst showed low cytotoxicity to bacterium and high stability under LED lamp irradiation. Facile preparation, high photocatalytic efficiency, good stability and reusability, and magnetic recovery property endow Fe@ZnO0.6S0.4 nanocomposite to be a promising photocatalytic material for bacterial inactivation.

  11. Rapid thermal reduced graphene oxide/Pt-TiO2 nanotube arrays for enhanced visible-light-driven photocatalytic reduction of CO2

    Science.gov (United States)

    Sim, Lan Ching; Leong, Kah Hon; Saravanan, Pichiah; Ibrahim, Shaliza

    2015-12-01

    In this study, a complicate natural photosynthesis process was prototyped through a photocatalysis process by reducing CO2 to light hydrocarbon, CH4. The composite photocatalyst employed for this study utilized Pt nanoparticles (Pt NPs) and rapid thermal reduced graphene oxide (RGO) deposited over the surface of the TiO2 nanotube arrays (TNTs). The existence and contribution of both Pt NPs and RGO in the composite was confirmed through various analytical techniques including XRD, HRTEM, FESEM, Raman, FTIR, XPS, UV-DRS and photoluminescence (PL) analysis. The TNTs in the composite exhibited pure anatase phase. The absorption bands at around 450 nm obtained from UV-DRS spectrum supported the existence of LSPR phenomenon of Pt NPs. The promising lower work function of RGO promoted the electrons transfer from TNTs to RGO efficiently. The successful depositions of Pt and RGO onto the surface of TNTs contributed for the improved photocatalytic activity (total CH4 yield of 10.96 μmol m-2) in the reduction of CO2 over TNTs and Pt-TNTs. Both of RGO and Pt NPs are equally important to exert a significant impact on the improvement of CH4 production rates.

  12. An anti-photocorrosive photoanode based on a CdS/NixSy@NF heterostructure for visible-light-driven water splitting

    Science.gov (United States)

    Zhang, Dantong; Liu, Lulu; Zhang, Lei; Qi, Kun; Zhang, Haiyan; Cui, Xiaoqiang

    2017-10-01

    Photoelectrochemical (PEC) water splitting holds promise for both sustainable energy generation and energy storage. CdS, a sulphide semiconductor possessing a narrow band gap (2.4 eV) and high photocatalytic activity, has been widely used to build photoanodes for PEC water splitting; however, it also suffers from photocorrosion under irradiation. An innovative method is presented here to significantly improve the stability of CdS photoanodes by constructing a p-n junction comprising CdS/NixSy on nickel foam (NF) via a one-pot hydrothermal method. The n-type CdS is surrounded by p-type NixSy serving as a fast and effective hole receiver of excess holes from CdS. More importantly, the CdS/NixSy shows significantly improved PEC stability compared to the pure CdS electrode, with ≈70% of the initial photocurrent retained after 2000 s of irradiation (>420 nm). This work provides a new insight into the fabrication of other p-n junction self-assembled photoanodes to simultaneously enhance charge separation and transport for efficient and stable solar fuel production.

  13. Fabrication of magnetic Fe@ZnO{sub 0.6}S{sub 0.4} nanocomposite for visible-light-driven photocatalytic inactivation of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Ziling [State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Wu, Dan [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong Special Administrative Region (China); Wang, Wei, E-mail: weiwang@hust.edu.cn [State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Tan, Fatang [State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Ng, Tsz Wai [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong Special Administrative Region (China); Chen, Jianguo; Qiao, Xueliang [State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Wong, Po Keung, E-mail: pkwong@cuhk.edu.hk [School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong Special Administrative Region (China)

    2017-02-28

    Highlights: • Fe@ZnO{sub 0.6}S{sub 0.4} was prepared by a facile two-step precipitation method. • Fe@ZnO{sub 0.6}S{sub 0.4} exhibited high photocatalytic activity under LED lamp irradiation. • Fe@ZnO{sub 0.6}S{sub 0.4} possessed good stability and reusability for bacterial inactivation. • Fe@ZnO{sub 0.6}S{sub 0.4} could be easily collected from the reaction solution by a magnet. • The release rate of metal ions from nanocomposite was kept at a very low level. - Abstract: Bacterial inactivation by magnetic photocatalysts has now received growing interests due to the easy separation for recycle and reuse of photocatalysts. In this study, magnetic Fe@ZnO{sub 0.6}S{sub 0.4} photocatalyst was prepared by a facile two-step precipitation method. Multiple techniques such as X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffused reflectance spectra (UV-vis DRS) and vibrating sample magnetometer (VSM) were employed to characterize the structure, morphology and physicochemical properties of the photocatalyst. The as-obtained Fe@ZnO{sub 0.6}S{sub 0.4} possessing magnetic property was easily collected from the reaction system by a magnet. Under white light-emitting-diode (LED) lamp irradiation, Fe@ZnO{sub 0.6}S{sub 0.4} nanocomposite could completely inactivate 7-log of Escherichia coli K-12 within 5 h. More importantly, almost no decrease of photocatalytic efficiency in bacterial inactivation was observed even after five consecutive cycles, demonstrating Fe@ZnO{sub 0.6}S{sub 0.4} exhibited good stability for reuse. The low released rate of Fe{sup 2+}/Fe{sup 3+} and Zn{sup 2+} from Fe@ZnO{sub 0.6}S{sub 0.4} composite further indicated the photocatalyst showed low cytotoxicity to bacterium and high stability under LED lamp irradiation. Facile preparation, high photocatalytic efficiency, good stability and reusability, and magnetic recovery property endow Fe@ZnO{sub 0.6}S{sub 0.4} nanocomposite to be a promising photocatalytic material for bacterial inactivation.

  14. The NAD(+) precursor nicotinamide riboside decreases exercise performance in rats.

    Science.gov (United States)

    Kourtzidis, Ioannis A; Stoupas, Andreas T; Gioris, Ioannis S; Veskoukis, Aristidis S; Margaritelis, Nikos V; Tsantarliotou, Maria; Taitzoglou, Ioannis; Vrabas, Ioannis S; Paschalis, Vassilis; Kyparos, Antonios; Nikolaidis, Michalis G

    2016-01-01

    Nicotinamide adenine dinucleotide (NAD(+)) and its phosphorylated form (NADP(+)) are key molecules in ubiquitous bioenergetic and cellular signaling pathways, regulating cellular metabolism and homeostasis. Thus, supplementation with NAD(+) and NADP(+) precursors emerged as a promising strategy to gain many and multifaceted health benefits. In this proof-of-concept study, we sought to investigate whether chronic nicotinamide riboside administration (an NAD(+) precursor) affects exercise performance. Eighteen Wistar rats were equally divided in two groups that received either saline vehicle or nicotinamide riboside at a dose of 300 mg/kg body weight/day for 21 days via gavage. At the end of the 21-day administration protocol, both groups performed an incremental swimming performance test. The nicotinamide riboside group showed a tendency towards worse physical performance by 35 % compared to the control group at the final 10 % load (94 ± 53 s for the nicotinamide riboside group and 145 ± 59 s for the control group; P = 0.071). Our results do not confirm the previously reported ergogenic effect of nicotinamide riboside. The potentially negative effect of nicotinamide riboside administration on physical performance may be attributed to the pleiotropic metabolic and redox properties of NAD(+) and NADP(+).

  15. Nicotinamide prevents ultraviolet radiation-induced cellular energy loss.

    Science.gov (United States)

    Park, Joohong; Halliday, Gary M; Surjana, Devita; Damian, Diona L

    2010-01-01

    UV radiation is carcinogenic by causing mutations in the skin and also by suppressing cutaneous antitumor immunity. We previously found nicotinamide (vitamin B3) to be highly effective at reducing UV-induced immunosuppression in human volunteers, with microarray studies on in vivo irradiated human skin suggesting that nicotinamide normalizes subsets of apoptosis, immune function and energy metabolism-related genes that are downregulated by UV exposure. Using human adult low calcium temperature keratinocytes, we further investigated nicotinamide's effects on cellular energy metabolism. We found that nicotinamide prevented UV-induced cellular ATP loss and protected against UV-induced glycolytic blockade. To determine whether nicotinamide alters the effects of UV-induced oxidative stress posttranslationally, we also measured UV-induced reactive oxygen species (ROS). Nicotinamide had no effect on ROS formation, and at the low UV doses used in these studies, equivalent to ambient daily sun exposure, there was no evidence of apoptosis. Hence, nicotinamide appears to exert its UV protective effects on the skin via its role in cellular energy pathways.

  16. Evaluation of nicotinamide microemulsion on the skin penetration enhancement.

    Science.gov (United States)

    Boonme, Prapaporn; Boonthongchuay, Chalida; Wongpoowarak, Wibul; Amnuaikit, Thanaporn

    2016-01-01

    This study purposed to evaluate a microemulsion containing nicotinamide for its characteristics, stability, and skin penetration and retention comparing with a solution of nicotinamide in 2:1 mixture of water and isopropyl alcohol (IPA). The microemulsion system was composed of 1:1 mixture of Span80 and Tween80 as a surfactant mixture, isopropyl palmitate (IPP) as an oil phase, and 2:1 mixture of water and IPA as an aqueous phase. Nicotinamide microemulsion was prepared by dissolving the active in the aqueous phase before simply mixing with the other components. It was determined for its characteristics and stability under various conditions. The skin penetration and retention studies of nicotinamide microemulsion and solution were performed by modified Franz diffusion cells, using newborn pig skin as the membrane. The results showed that nicotinamide microemulsion could be obtained as clear yellowish liquid, was water-in-oil (w/o) type, possessed Newtonian flow, and exhibited physicochemical stability when kept at 4 °C and room temperature (≈30 ± 2 °C) during 3 months. From the skin penetration data, the microemulsion could enhance the skin penetration of nicotinamide comparing with the solution. Additionally, nicotinamide microemulsion could provide much higher amount of skin retention than that of skin penetration, resulting in suitability for a cosmeceutical product.

  17. [Intervention of nicotinamide on skin melanin genesis after UVA exposed].

    Science.gov (United States)

    Patam, Muhammad; Jin, Xi-peng; Zhang, Yu-bin; Pan, Jian-ying; Shen, Guang-zu

    2007-08-01

    To investigate the interference effect of nicotinamide on UVA-induced melanin genesis and melanin transport in human skin melanocyte. The optimum UVA dose expected to cause cell proliferation: 0.2 J/cm(2), nicotinamide was added immediately after the 0.2 J/cm(2) UVA exposure and the melanin content, cell cycles, cell apoptosis and mRNA express level were measured respectively. Melanin content in melanocytes was increased significantly after exposed to 0.2 J/cm(2) UVA. Melanin content in melanocytes was decreased after treatment with 10.0 mmol/ml nicotinamide following UVA exposure, but the cell cycles and the cell apoptosis rate were not significantly altered. mRNA express levels of TYR, TRP-1 were modulated by nicotinamide. Nicotinamide has more effect on decreasing melanin genesis after UVA exposure, nicotinamide also plays a role in modulating the mRNA express of TYR, TRP-1 gene. It is possible to consider nicotinamide as an efficient and safe sun screen to provide a certain level of protection for UVA exposed skin.

  18. The Vitamin Nicotinamide: Translating Nutrition into Clinical Care

    Directory of Open Access Journals (Sweden)

    Zhao Zhong Chong

    2009-09-01

    Full Text Available Nicotinamide, the amide form of vitamin B3 (niacin, is changed to its mononucleotide compound with the enzyme nicotinic acide/nicotinamide adenylyltransferase, and participates in the cellular energy metabolism that directly impacts normal physiology. However, nicotinamide also influences oxidative stress and modulates multiple pathways tied to both cellular survival and death. During disorders that include immune system dysfunction, diabetes, and aging-related diseases, nicotinamide is a robust cytoprotectant that blocks cellular inflammatory cell activation, early apoptotic phosphatidylserine exposure, and late nuclear DNA degradation. Nicotinamide relies upon unique cellular pathways that involve forkhead transcription factors, sirtuins, protein kinase B (Akt, Bad, caspases, and poly (ADP-ribose polymerase that may offer a fine line with determining cellular longevity, cell survival, and unwanted cancer progression. If one is cognizant of the these considerations, it becomes evident that nicotinamide holds great potential for multiple disease entities, but the development of new therapeutic strategies rests heavily upon the elucidation of the novel cellular pathways that nicotinamide closely governs.

  19. Solar light driven enhanced photocatalytic degradation of brilliant green dye based on ZnS quantum dots

    Science.gov (United States)

    Kaur, Sharanjit; Sharma, Shelja; Umar, Ahmad; Singh, Surinder; Mehta, S. K.; Kansal, Sushil Kumar

    2017-03-01

    Herein, we report the successful synthesis, detailed characterization and solar-light driven photocatalytic degradation of zinc sulfide (ZnS) quantum dots. The ZnS quantum dots were synthesized in high yield by co-precipitation method using sodium dodecyl sulfate as a stabilizing agent. The as-synthesized ZnS quantum dots were characterized in detail in terms of their morphological, structural, compositional, thermal and optical properties. The detailed characterizations confirmed that the synthesized quantum dots are well-crystalline, possessing cubic phase of zinc blende structure, pure and exhibiting good optical properties. The synthesized quantum dots were further used as potential photocatalyst for the photocatalytic degradation of brilliant green dye under solar-light irradiation which exhibited 88% degradation. The process parameters, such as pH and catalyst dose, for the photocatalytic degradation of brilliant green dye was elaborately examined in order to evaluate the highest degradation rate of targeted dye. Further, the experimental data were fitted well in the pseudo-first order kinetic model. Finally, a possible mechanism for the photocatalytic degradation of brilliant green dye by ZnS quantum dots was also suggested.

  20. Light-driven dinitrogen reduction catalyzed by a CdS:nitrogenase MoFe protein biohybrid.

    Science.gov (United States)

    Brown, Katherine A; Harris, Derek F; Wilker, Molly B; Rasmussen, Andrew; Khadka, Nimesh; Hamby, Hayden; Keable, Stephen; Dukovic, Gordana; Peters, John W; Seefeldt, Lance C; King, Paul W

    2016-04-22

    The splitting of dinitrogen (N2) and reduction to ammonia (NH3) is a kinetically complex and energetically challenging multistep reaction. In the Haber-Bosch process, N2 reduction is accomplished at high temperature and pressure, whereas N2 fixation by the enzyme nitrogenase occurs under ambient conditions using chemical energy from adenosine 5'-triphosphate (ATP) hydrolysis. We show that cadmium sulfide (CdS) nanocrystals can be used to photosensitize the nitrogenase molybdenum-iron (MoFe) protein, where light harvesting replaces ATP hydrolysis to drive the enzymatic reduction of N2 into NH3 The turnover rate was 75 per minute, 63% of the ATP-coupled reaction rate for the nitrogenase complex under optimal conditions. Inhibitors of nitrogenase (i.e., acetylene, carbon monoxide, and dihydrogen) suppressed N2 reduction. The CdS:MoFe protein biohybrids provide a photochemical model for achieving light-driven N2 reduction to NH3. Copyright © 2016, American Association for the Advancement of Science.

  1. A phylogenetically distinctive and extremely heat stable light-driven proton pump from the eubacterium Rubrobacter xylanophilus DSM 9941T.

    Science.gov (United States)

    Kanehara, Kanae; Yoshizawa, Susumu; Tsukamoto, Takashi; Sudo, Yuki

    2017-03-14

    Rhodopsins are proteins that contain seven transmembrane domains with a chromophore retinal and that function as photoreceptors for light-energy conversion and light-signal transduction in a wide variety of organisms. Here we characterized a phylogenetically distinctive new rhodopsin from the thermophilic eubacterium Rubrobacter xylanophilus DSM 9941T that was isolated from thermally polluted water. Although R. xylanophilus rhodopsin (RxR) is from Actinobacteria, it is located between eukaryotic and archaeal rhodopsins in the phylogenetic tree. Escherichia coli cells expressing RxR showed a light-induced decrease in environmental pH and inhibition by a protonophore, indicating that it works as a light-driven outward proton pump. We characterized purified RxR spectroscopically, and showed that it has an absorption maximum at 541 nm and binds nearly 100% all-trans retinal. The pKa values for the protonated retinal Schiff base and its counterion were estimated to be 10.7 and 1.3, respectively. Time-resolved flash-photolysis experiments revealed the formation of a red-shifted intermediate. Of note, RxR showed an extremely high thermal stability in comparison with other proton pumping rhodopsins such as thermophilic rhodopsin TR (by 16-times) and bacteriorhodopsin from Halobacterium salinarum (HsBR, by 4-times).

  2. Action of nucleotide phosphotransferase of Escherichia coli on nicotinamide riboside and nicotinamide mononucleotide.

    Science.gov (United States)

    Brunngraber, E F; Chargaff, E

    1977-01-01

    The action of the nucleotide phosphotransferase of Escherichia coli on nicotinamide riboside and on its 5'-phosphate results in the addition of one phosphate moiety to each of the substrates. Although the proof is not conclusive, it is likely that the phosphate group is transferred to the 3'-hydroxyl of the ribose. This is in contrast to the behavior of the enzyme toward NAD in which only the adenylic acid portion is phosphorylated enzymically. PMID:144913

  3. The chemistry of nicotinamide adenine dinucleotide (NAD) analogues containing C-nucleosides related to nicotinamide riboside.

    Science.gov (United States)

    Pankiewicz, Krzysztof W; Watanabe, Kyoichi A; Lesiak-Watanabe, Krystyna; Goldstein, Barry M; Jayaram, Hiremagalur N

    2002-04-01

    Oncolytic C-nucleosides, tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide) and benzamide riboside (3-beta-D-ribofuranosylbenzamide) are converted in cell into active metabolites thiazole-4-carboxamide- and benzamide adenine dinucleotide, TAD and BAD, respectively. TAD and BAD as NAD analogues were found to bind at the nicotinamide adenine dinucleotide (cofactor NAD) site of inosine monophosphate dehydrogenase (IMPDH), an important target in cancer treatment. The synthesis and evaluation of anticancer activity of a number of C-nucleosides related to tiazofurin and nicotinamide riboside then followed and are reviewed herein. Interestingly, pyridine C-nucleosides (such as C-nicotinamide riboside) are not metabolized into the corresponding NAD analogues in cell. Their conversion by chemical methods is described. As dinucleotides these compounds show inhibition of IMPDH in low micromolar level. Also, the synthesis of BAD in metabolically stable bis(phosphonate) form is discussed indicating the usefulness of such preformed inhibitors in drug development. Among tiazofurin analogues, Franchetti and Grifantini found, that the replacement of the sulfur by oxygen (as in oxazafurin) but not the removal of nitrogen (tiophenfurin) of the thiazole ring resulted in inactive compounds. The anti cancer activity of their synthetic dinucleotide analogues indicate that inactive compounds are not only poorly metabolized in cell but also are weak inhibitors of IMPDH as dinucleotides.

  4. Extracellular nicotinamide phosphoribosyltransferase, a new cancer metabokine

    Science.gov (United States)

    Grolla, Ambra A; Travelli, Cristina

    2016-01-01

    Abstract In this review, we focus on the secreted form of nicotinamide phosphoribosyltransferase (NAMPT); extracellular NAMPT (eNAMPT), also known as pre‐B cell colony‐enhancing factor or visfatin. Although intracellular NAMPT is a key enzyme in controlling NAD metabolism, eNAMPT has been reported to function as a cytokine, with many roles in physiology and pathology. Circulating eNAMPT has been associated with several metabolic and inflammatory disorders, including cancer. Because cytokines produced in the tumour micro‐environment play an important role in cancer pathogenesis, in part by reprogramming cellular metabolism, future improvements in cancer immunotherapy will require a better understanding of the crosstalk between cytokine action and tumour biology. In this review, the knowledge of eNAMPT in cancer will be discussed, focusing on its immunometabolic function as a metabokine, its secretion, its mechanism of action and possible roles in the cancer micro‐environment. PMID:27128025

  5. An efficient chemical synthesis of nicotinamide riboside (NAR) and analogues.

    Science.gov (United States)

    Tanimori, Shinji; Ohta, Takeshi; Kirihata, Mitsunori

    2002-04-22

    A simple and efficient synthesis of nicotinamide riboside (NAR) 1 and derivatives 4 and 5 via trimethylsilyl trifluoromethanesulfonate (TMSOTf)-mediated N-glycosilation followed by spontaneous deacetylation by treating with methanol is reported.

  6. Better than Nature: Nicotinamide Biomimetics That Outperform Natural Coenzymes

    NARCIS (Netherlands)

    Knaus, T.; Paul, C.E.; Levy, C.W.; de Vries, S.; Mutti, F.G.; Hollmann, F.; Scrutton, N.S.

    2016-01-01

    The search for affordable, green biocatalytic processes is a challenge for chemicals manufacture. Redox biotransformations are potentially attractive, but they rely on unstable and expensive nicotinamide coenzymes that have prevented their widespread exploitation. Stoichiometric use of natural

  7. Ultrafast exciton dynamics and light-driven H2 evolution in colloidal semiconductor nanorods and Pt-tipped nanorods.

    Science.gov (United States)

    Wu, Kaifeng; Zhu, Haiming; Lian, Tianquan

    2015-03-17

    distributions. The effect of the exciton dynamics on photoreduction reactions is illustrated using methyl viologen (MV(2+)) as a model electron acceptor. The steady-state MV(2+) photoreduction quantum yield of CdSe/CdS dot-in-rod NRs approaches unity under rod excitation, much larger than CdSe QDs and CdSe/CdS core/shell QDs. Detailed time-resolved studies show that in quasi-type II CdSe/CdS NRs and type II ZnSe/CdS NRs strong quantum confinement in the radial direction facilitates fast electron transfer and hole removal, whereas the fast carrier mobility along the axial direction enables long distance charge separation and slow charge recombination, which is essential for efficient MV(2+) photoreduction. The NR/MV(2+) relay system can be coupled to Pt nanoparticles in solution for light-driven H2 generation. Alternatively, Pt-tipped CdS and CdSe/CdS NRs provide fully integrated all inorganic systems for light-driven H2 generation. In CdS-Pt and CdSe/CdS-Pt hetero-NRs, ultrafast hole trapping on the CdS rod surface or in CdSe core enables efficient electron transfer from NRs to Pt tips by suppressing hole and energy transfer. It is shown that the quantum yields of photodriven H2 generation using these heterostructures correlate well with measured hole transfer rates from NRs to sacrificial donors, revealing that hole removal is the key efficiency-limiting step. These findings provide important insights for designing more efficient quantum confined NR and NR-Pt based systems for solar-to-fuel conversion.

  8. Redirecting photosynthetic electron flow into light-driven synthesis of alternative products including high-value bioactive natural compounds.

    Science.gov (United States)

    Lassen, Lærke Münter; Nielsen, Agnieszka Zygadlo; Ziersen, Bibi; Gnanasekaran, Thiyagarajan; Møller, Birger Lindberg; Jensen, Poul Erik

    2014-01-17

    Photosynthesis in plants, green algae, and cyanobacteria converts solar energy into chemical energy in the form of ATP and NADPH, both of which are used in primary metabolism. However, often more reducing power is generated by the photosystems than what is needed for primary metabolism. In this review, we discuss the development in the research field, focusing on how the photosystems can be used as synthetic biology building blocks to channel excess reducing power into light-driven production of alternative products. Plants synthesize a large number of high-value bioactive natural compounds. Some of the key enzymes catalyzing their biosynthesis are the cytochrome P450s situated in the endoplasmic reticulum. However, bioactive compounds are often synthesized in low quantities in the plants and are difficult to produce by chemical synthesis due to their often complex structures. Through a synthetic biology approach, enzymes with a requirement for reducing equivalents as cofactors, such as the cytochrome P450s, can be coupled directly to the photosynthetic energy output to obtain environmentally friendly production of complex chemical compounds. By relocating cytochrome P450s to the chloroplasts, reducing power can be diverted toward the reactions catalyzed by the cytochrome P450s. This provides a sustainable production method for high-value compounds that potentially can solve the problem of NADPH regeneration, which currently limits the biotechnological uses of cytochrome P450s. We describe the approaches that have been taken to couple enzymes to photosynthesis in vivo and to photosystem I in vitro and the challenges associated with this approach to develop new green production platforms.

  9. "Watching" the Dark State in Ultrafast Nonadiabatic Photoisomerization Process of a Light-Driven Molecular Rotary Motor.

    Science.gov (United States)

    Pang, Xiaojuan; Cui, Xueyan; Hu, Deping; Jiang, Chenwei; Zhao, Di; Lan, Zhenggang; Li, Fuli

    2017-02-16

    Photoisomerization dynamics of a light-driven molecular rotary motor, 9-(2-methyl-2,3-dihydro-1H-cyclopenta[a]naphthalen-1-ylidene)-9H-fluorene, is investigated with trajectory surface-hopping dynamics at the semiempirical OM2/MRCI level. The rapid population decay of the S1 excited state for the M isomer is observed, with two different decay time scales (500 fs and 1.0 ps). By weighting the contributions of fast and slow decay trajectories, the averaged lifetime of the S1 excited state is about 710 fs. The calculated quantum yield of the M-to-P photoisomerization of this molecular rotary motor is about 59.9%. After the S0 → S1 excitation, the dynamical process of electronic decay is followed by twisting about the central C═C double bond and the motion of pyramidalization at the carbon atom of the stator-axle linkage. Although two S0/S1 minimum-energy conical intersections are obtained at the OM2/MRCI level, only one conical intersection is found to be responsible for the nonadiabatic dynamics. The existence of "dark state" in the molecular rotary motor is confirmed through the simulated time-resolved fluorescence emission spectrum. Both quenching and red shift of fluorescence emission spectrum observed by Conyard et al. [ Conyard, J.; Addison, K.; Heisler, I. A.; Cnossen, A.; Browne, W. R.; Feringa, B. L.; Meech, S. R. Nat. Chem. 2012 , 4 , 547 - 551 ; Conyard, J.; Conssen, A.; Browne, W. R.; Feringa, B. L.; Meech, S. R. J. Am. Chem. Soc. 2014 , 136 , 9692 - 9700 ] are well understood. We find that this "dark state" in the molecular rotary motor is not a new electronic state, but the "dark region" with low oscillator strength on the initial S1 state.

  10. Nicotinamide reduces photodynamic therapy-induced immunosuppression in humans.

    Science.gov (United States)

    Thanos, S M; Halliday, G M; Damian, D L

    2012-09-01

    The immune suppressive effects of topical photodynamic therapy (PDT) are potential contributors to treatment failure after PDT for nonmelanoma skin cancer. Nicotinamide (vitamin B(3) ) prevents immune suppression by ultraviolet radiation, but its effects on PDT-induced immunosuppression are unknown. To determine the effects of topical and oral nicotinamide on PDT-induced immunosuppression in humans. Twenty healthy Mantoux-positive volunteers received 5% nicotinamide lotion or vehicle to either side of the back daily for 3 days. Another group of 30 volunteers received 500 mg oral nicotinamide or placebo twice daily for 1 week in a randomized, double-blinded, crossover design. In each study, methylaminolaevulinate cream was applied to discrete areas on the back, followed by narrowband red light irradiation (37 J cm(-2) ) delivered at high (75 mW cm(-2) ) or low (15 mW cm(-2) ) irradiance rates. Adjacent, nonirradiated sites served as controls. Delayed-type hypersensitivity (Mantoux) reactions were assessed at treatment and control sites to determine immunosuppression. High irradiance rate PDT with vehicle or with placebo caused significant immunosuppression (equivalent to 48% and 50% immunosuppression, respectively; both P nicotinamide reduced this immunosuppression by 59% and 66%, respectively (both P nicotinamide study (15% immunosuppression, not significant), but caused 22% immunosuppression in the oral study (placebo arm; P = 0·006); nicotinamide reduced this immunosuppression by 69% (P = 0·045). While the clinical relevance of these findings is currently unknown, nicotinamide may provide an inexpensive means of preventing PDT-induced immune suppression and enhancing PDT cure rates. © 2012 The Authors. BJD © 2012 British Association of Dermatologists.

  11. [Protective effect of nicotinamide in a mouse Parkinson's disease model].

    Science.gov (United States)

    Xu, Jing; Xu, Sheng-quan; Liang, Jie; Lu, Yuan; Luo, Jian-hong; Jin, Jing-hua

    2012-03-01

    To examine the protective effect of nicotinamide on 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) in mouse model and its mechanisms. Parkinson's disease was induced by injection of MPTP in adult male C57BL/6 mice, nicotinamide (500 mg/kg,i.p.) was given prior to subacute (30 mg/kg/d × 5 d,i.p.) MPTP administration. Locomotor activities, striatal dopamine levels, lactate dehydrogenase (LDH) and NO synthase (NOS) activities of whole brains and striatum were analyzed at d5 after last MPTP injections. Pretreatment with nicotinamide significantly improved the locomotor activity in the open-field test (Pclimbing test. Nicotinamide administration resulted in sparing striatal dopamine levels from MPTP-induced dopamine depletion. There was no significant difference in LDH and NOS activities in the whole brains among the groups; but the activities in the striatum were drastically elevated after MPTP treatment. Nicotinamide pretreatment markedly inhibited MPTP-induced LDH and NOS activities (P0.05). Nicotinamide protects dopaminergic neurons against MPTP-induced neurodegeneration,which suggests that the neuroprotective effects be associated with the inhibition of cell injuries and NOS activities.

  12. Different conical intersections control nonadiabatic photochemistry of fluorene light-driven molecular rotary motor: A CASSCF and spin-flip DFT study

    Science.gov (United States)

    Li, Yuanying; Liu, Fengyi; Wang, Bin; Su, Qingqing; Wang, Wenliang; Morokuma, Keiji

    2016-12-01

    We report the light-driven isomerization mechanism of a fluorene-based light-driven rotary motor (corresponding to Feringa's 2nd generation rotary motor, [M. M. Pollard et al., Org. Biomol. Chem. 6, 507-512 (2008)]) at the complete active space self-consistent field (CASSCF) and spin-flip time-dependent density functional theory (TDDFT) (SFDFT) levels, combined with the complete active space second-order perturbation theory (CASPT2) single-point energy corrections. The good consistence between the SFDFT and CASSCF results confirms the capability of SFDFT in investigating the photoisomerization step of the light-driven molecular rotary motor, and proposes the CASPT2//SFDFT as a promising and effective approach in exploring photochemical processes. At the mechanistic aspect, for the fluorene-based motor, the S1/S0 minimum-energy conical intersection (MECIs) caused by pyramidalization of a fluorene carbon have relatively low energies and are easily accessible by the reactive molecule evolution along the rotary reaction path; therefore, the fluorene-type MECIs play the dominant role in nonadiabatic decay, as supported by previous experimental and theoretical works. Comparably, the other type of MECIs that results from pyramidalization of an indene carbon, which has been acting as the dominant nonadiabatic decay channel in the stilbene motor, is energetically inaccessible, thus the indene-type MECIs are "missing" in previous mechanistic studies including molecular dynamic simulations. A correlation between the geometric and electronic factors of MECIs and that of the S1 energy profile along the C═C rotary coordinate was found. The findings in current study are expected to deepen the understanding of nonadiabatic transition in the light-driven molecular rotary motor and provide insights into mechanistic tuning of their performance.

  13. Deprotonation of g-C3N4 with Na ions for efficient nonsacrificial water splitting under visible light

    DEFF Research Database (Denmark)

    Guo, Feng; Chen, Jingling; Zhang, Minwei

    2016-01-01

    Developing a photocatalyst with the necessary characteristics of being cheap, efficient and robust for visible-light-driven water splitting remains a serious challenge within the photocatalysis field. Herein, an effective strategy, deprotonating g-C3N4 with Na ions from low-cost precursors...

  14. Modulation of light-driven arousal by LIM-homeodomain transcription factor Apterous in large PDF-positive lateral neurons of the Drosophila brain.

    Science.gov (United States)

    Shimada, Naoto; Inami, Show; Sato, Shoma; Kitamoto, Toshihiro; Sakai, Takaomi

    2016-11-17

    Apterous (Ap), the best studied LIM-homeodomain transcription factor in Drosophila, cooperates with the cofactor Chip (Chi) to regulate transcription of specific target genes. Although Ap regulates various developmental processes, its function in the adult brain remains unclear. Here, we report that Ap and Chi in the neurons expressing PDF, a neuropeptide, play important roles in proper sleep/wake regulation in adult flies. PDF-expressing neurons consist of two neuronal clusters: small ventral-lateral neurons (s-LNvs) acting as the circadian pacemaker and large ventral-lateral neurons (l-LNvs) regulating light-driven arousal. We identified that Ap localizes to the nuclei of s-LNvs and l-LNvs. In light-dark (LD) cycles, RNAi knockdown or the targeted expression of dominant-negative forms of Ap or Chi in PDF-expressing neurons or l-LNvs promoted arousal. In contrast, in constant darkness, knockdown of Ap in PDF-expressing neurons did not promote arousal, indicating that a reduced Ap function in PDF-expressing neurons promotes light-driven arousal. Furthermore, Ap expression in l-LNvs showed daily rhythms (peaking at midnight), which are generated by a direct light-dependent mechanism rather than by the endogenous clock. These results raise the possibility that the daily oscillation of Ap expression in l-LNvs may contribute to the buffering of light-driven arousal in wild-type flies.

  15. Photogenerated carriers transfer in dye-graphene-SnO2 composites for highly efficient visible-light photocatalysis.

    Science.gov (United States)

    Zhuang, Shendong; Xu, Xiaoyong; Feng, Bing; Hu, Jingguo; Pang, Yaru; Zhou, Gang; Tong, Ling; Zhou, Yuxue

    2014-01-08

    The visible-light-driven photocatalytic activities of graphene-semiconductor catalysts have recently been demonstrated, however, the transfer pathway of photogenerated carriers especially where the role of graphene still remains controversial. Here we report graphene-SnO2 aerosol nanocomposites that exhibit more superior dye adsorption capacity and photocatalytic efficiency compared with pure SnO2 quantum dots, P25 TiO2, and pure graphene aerosol under the visible light. This study examines the origin of the visible-light-driven photocatalysis, which for the first time links to the synergistic effect of the cophotosensitization of the dye and graphene to SnO2. We hope this concept and corresponding mechanism of cophotosensitization could provide an original understanding for the photocatalytic reaction process at the level of carrier transfer pathway as well as a brand new approach to design novel and versatile graphene-based composites for solar energy conversion.

  16. Recycling nicotinamide. The transition-state structure of human nicotinamide phosphoribosyltransferase

    Science.gov (United States)

    Burgos, Emmanuel S.; Vetticatt, Mathew J.; Schramm, Vern L.

    2013-01-01

    Human nicotinamide phosphoribosyltransferase (NAMPT) replenishes the NAD pool and controls the activities of sirtuins (SIRT), mono- and poly-(ADP-ribose) polymerases (PARP) and NAD nucleosidase (CD38). The nature of the enzymatic transition-state (TS) is central to understanding the function of NAMPT. We determined the TS structure for pyrophosphorolysis of nicotinamide mononucleotide (NMN) by kinetic isotope effects (KIEs). With the natural substrates, NMN and pyrophosphate (PPi), the intrinsic KIEs of [1′-14C], [1-15N], [1′-3H] and [2′-3H] are 1.047, 1.029, 1.154 and 1.093, respectively. A unique quantum computational approach was used for TS analysis that included structural elements of the catalytic site. Without constraints (e.g. imposed torsion angles), the theoretical and experimental data are in good agreement. The quantum-mechanical calculations incorporated a crucial catalytic site residue (D313), two magnesium atoms and coordinated water molecules. The transition state model predicts primary 14C, α-secondary 3H, β-secondary 3H and primary 15N KIE close to the experimental values. The analysis reveals significant ribocation character at the TS. The attacking PPi nucleophile is weakly interacting (rC-O = 2.60 Å) and the N-ribosidic C1′-N bond is highly elongated at the TS (rC-N = 2.35 Å), consistent with an ANDN mechanism. Together with the crystal structure of the NMN•PPi•Mg2•enzyme complex, the reaction coordinate is defined. The enzyme holds the nucleophile and leaving group in relatively fixed positions to create a reaction coordinate with C1′-anomeric migration from nicotinamide to the PPi. The transition state is reached by a 0.85 Å migration of C1′. PMID:23373462

  17. A review of nicotinamide: treatment of skin diseases and potential side effects.

    Science.gov (United States)

    Rolfe, Heidi M

    2014-12-01

    Nicotinamide, also known as niacinamide, is the amide form of vitamin B3. It is a precursor of essential coenzymes for numerous reactions in the body including adenosine triphosphate (ATP) production. Nicotinic acid, also known as niacin, is converted into nicotinamide in the body. The use of topical nicotinamide in the treatment of acne vulgaris; melasma; atopic dermatitis; rosacea; and oral nicotinamide in preventing nonmelanoma skin cancer is discussed. The possible side effects and consequences of excessive nicotinamide exposure are reviewed, including suggestions nicotinamide might have a role in the development of diabetes, Parkinson's disease, and liver damage. © 2014 Wiley Periodicals, Inc.

  18. Visibility Matters

    DEFF Research Database (Denmark)

    Wildgaard, Lorna Elizabeth

    2015-01-01

    Research production, which earns universities money, is accredited publications in peer-reviewed journals and books. Increasing research productivity is one policy amongst many used by management to boost growth and income. It is time for a pat on the back, the growth of knowledge and visibility...

  19. Nicotinamide riboside kinase structures reveal new pathways to NAD+.

    Directory of Open Access Journals (Sweden)

    Wolfram Tempel

    2007-10-01

    Full Text Available The eukaryotic nicotinamide riboside kinase (Nrk pathway, which is induced in response to nerve damage and promotes replicative life span in yeast, converts nicotinamide riboside to nicotinamide adenine dinucleotide (NAD+ by phosphorylation and adenylylation. Crystal structures of human Nrk1 bound to nucleoside and nucleotide substrates and products revealed an enzyme structurally similar to Rossmann fold metabolite kinases and allowed the identification of active site residues, which were shown to be essential for human Nrk1 and Nrk2 activity in vivo. Although the structures account for the 500-fold discrimination between nicotinamide riboside and pyrimidine nucleosides, no enzyme feature was identified to recognize the distinctive carboxamide group of nicotinamide riboside. Indeed, nicotinic acid riboside is a specific substrate of human Nrk enzymes and is utilized in yeast in a novel biosynthetic pathway that depends on Nrk and NAD+ synthetase. Additionally, nicotinic acid riboside is utilized in vivo by Urh1, Pnp1, and Preiss-Handler salvage. Thus, crystal structures of Nrk1 led to the identification of new pathways to NAD+.

  20. Nicotinamide riboside kinase structures reveal new pathways to NAD+.

    Science.gov (United States)

    Tempel, Wolfram; Rabeh, Wael M; Bogan, Katrina L; Belenky, Peter; Wojcik, Marzena; Seidle, Heather F; Nedyalkova, Lyudmila; Yang, Tianle; Sauve, Anthony A; Park, Hee-Won; Brenner, Charles

    2007-10-02

    The eukaryotic nicotinamide riboside kinase (Nrk) pathway, which is induced in response to nerve damage and promotes replicative life span in yeast, converts nicotinamide riboside to nicotinamide adenine dinucleotide (NAD+) by phosphorylation and adenylylation. Crystal structures of human Nrk1 bound to nucleoside and nucleotide substrates and products revealed an enzyme structurally similar to Rossmann fold metabolite kinases and allowed the identification of active site residues, which were shown to be essential for human Nrk1 and Nrk2 activity in vivo. Although the structures account for the 500-fold discrimination between nicotinamide riboside and pyrimidine nucleosides, no enzyme feature was identified to recognize the distinctive carboxamide group of nicotinamide riboside. Indeed, nicotinic acid riboside is a specific substrate of human Nrk enzymes and is utilized in yeast in a novel biosynthetic pathway that depends on Nrk and NAD+ synthetase. Additionally, nicotinic acid riboside is utilized in vivo by Urh1, Pnp1, and Preiss-Handler salvage. Thus, crystal structures of Nrk1 led to the identification of new pathways to NAD+.

  1. 4-Hydroxy-3-methoxybenzaldehyde–nicotinamide (1/1

    Directory of Open Access Journals (Sweden)

    Fiona N.-F. How

    2011-12-01

    Full Text Available In the title compound, C6H6N2O·C8H8O3, an equimolar co-crystal of nicotinamide and vanillin, the aromatic ring and the amide fragment of the nicotinamide molecule make a dihedral angle of 32.6 (2°. The vanillin molecule is almost planar, with an r.m.s. deviation for all non-H atoms of 0.0094 Å. The vaniline and nicotinamide aromatic rings are nearly coplanar, the dihedral angle between them being 3.20 (9°. In the crystal, the two components are linked through N—H...O and O—H...N hydrogen bonds into chains along the a axis. The chains are connected via C—H...O interactions, forming a three-dimensional polymeric structure.

  2. Nicotinamide riboside phosphorylase from beef liver: purification and characterization.

    Science.gov (United States)

    Imai, T; Anderson, B M

    1987-04-01

    Nicotinamide riboside phosphorylase (NR phosphorylase) from beef liver has been purified to apparent homogeneity at 300-fold purification with a 35% yield. Kinetic constants for the enzyme-catalyzed phosphorolysis were as follows Knicotinamide riboside, 2.5 +/- 0.4 mM; Kinorganic phosphate, 0.50 +/- 0.12 mM; Vmax, 410 +/- 30 X 10(-6) mol min-1 mg protein-1, respectively. The molecular weights of the native enzyme and subunit structure were determined to be 131,000 and 32,000, respectively, suggesting the beef liver NR phosphorylase to be tetrameric in structure and consistent with the presence of identical subunits. The amino acid composition was shown to be very similar to that reported for human erythrocyte purine-nucleoside phosphorylase but differing considerably from that found for rat liver purine-nucleoside phosphorylase. In addition to catalytic activity with nicotinamide riboside, the beef liver enzyme catalyzed a phosphorolytic reaction with inosine and guanosine exhibiting activity ratios, nicotinamide riboside:inosine: guanosine of 1.00:0.35:0.29, respectively. These ratios of activity remained constant throughout purification of the beef liver enzyme and no separation of these activities was detected. Phosphorolysis of nicotinamide riboside was inhibited competitively by inosine (Ki = 75 microM) and guanosine (Ki = 75 microM). Identical rates of thermal denaturation of the beef liver enzyme were observed when determined for the phosphorolysis of either nicotinamide riboside or inosine. These observations coupled with studies of pH and specific buffer effects indicate the phosphorolysis of nicotinamide riboside, inosine, and guanosine to be catalyzed by the same enzyme.

  3. Theophylline-nicotinamide cocrystal formation in physical mixture during storage.

    Science.gov (United States)

    Ervasti, Tuomas; Aaltonen, Jaakko; Ketolainen, Jarkko

    2015-01-01

    Pharmaceutically relevant properties, such as solubility and dissolution rate, of active pharmaceutical ingredients can be enhanced by cocrystal formation. Theophylline and nicotinamide are known to form cocrystals, for example if subjected to solid-state grinding. However, under appropriate conditions, cocrystals can also form in physical mixtures without any mechanical activation. The purpose of this work was to study whether theophylline and nicotinamide could form cocrystals spontaneously, without mechanical activation. Crystalline theophylline and nicotinamide powders were gently mixed manually in a 1:1 molar ratio and stored at different relative humidity and temperature conditions. The solid state of the samples was analyzed by differential scanning calorimetry, Raman spectroscopy and X-ray powder diffractometry. Three different variations of theophylline were used as starting materials, e.g., two size fractions of theophylline anhydrate (large 710 μm-1 mm and small 180-355 μm), and monohydrate (recrystallized from water). As a reference, anhydrous theophylline-nicotinamide cocrystals were prepared by solid-state grinding. The results of this study indicate that theophylline-nicotinamide cocrystals can form without any mechanical activation from physical mixtures of theophylline and nicotinamide during storage. For anhydrous samples, storage humidity was found to be a critical parameter for cocrystal formation. Increasing temperature was also found to have an accelerating effect on the transformation. The effect of particle size of anhydrous theophylline on the transformation rate could not be completely resolved; DSC and Raman indicated slightly faster transformation with a physical mixture prepared from large size fraction of anhydrous theophylline, but the differences were only minor. Cocrystal formation was also observed in the physical mixture prepared from theophylline monohydrate, but the rate was not as high as with samples prepared from anhydrous

  4. Nicotinamide and skin cancer chemoprevention: The jury is still out.

    Science.gov (United States)

    Gilmore, Stephen J

    2018-02-01

    Following the publication of the results of a Phase III trial, the administration of oral nicotinamide has been widely advocated as effective in non-melanoma skin cancer chemoprevention in high-risk individuals. However, I performed a Bayesian analysis of the reported findings and show there is insufficient evidence to demonstrate its efficacy, highlighting the significant probability that the positive conclusions drawn will not be reproducible. Given the potential widespread use of oral nicotinamide, future position statements regarding its efficacy are likely to require higher standards of evidence. © 2017 The Australasian College of Dermatologists.

  5. Syntheses of nicotinamide riboside and derivatives: effective agents for increasing nicotinamide adenine dinucleotide concentrations in mammalian cells.

    Science.gov (United States)

    Yang, Tianle; Chan, Noel Yan-Ki; Sauve, Anthony A

    2007-12-27

    A new two-step methodology achieves stereoselective synthesis of beta-nicotinamide riboside and a series of related amide, ester, and acid nucleosides. Compounds were prepared through a triacetylated-nicotinate ester nucleoside, via coupling of either ethylnicotinate or phenylnicotinate with 1,2,3,5-tetra-O-acetyl-beta-D-ribofuranose. Nicotinamide riboside, nicotinic acid riboside, O-ethylnicotinate riboside, O-methylnicotinate riboside, and several N-alkyl derivatives increased NAD+ concentrations from 1.2-2.7-fold in several mammalian cell lines. These findings establish bioavailability and potent effects of these nucleosides in stimulating the increase of NAD+ concentrations in mammalian cells.

  6. Anchoring a plant cytochrome P450 via PsaM to the thylakoids in Synechococcus sp. PCC 7002: evidence for light-driven biosynthesis.

    Directory of Open Access Journals (Sweden)

    Lærke Münter Lassen

    Full Text Available Plants produce an immense variety of specialized metabolites, many of which are of high value as their bioactive properties make them useful as for instance pharmaceuticals. The compounds are often produced at low levels in the plant, and due to their complex structures, chemical synthesis may not be feasible. Here, we take advantage of the reducing equivalents generated in photosynthesis in developing an approach for producing plant bioactive natural compounds in a photosynthetic microorganism by functionally coupling a biosynthetic enzyme to photosystem I. This enables driving of the enzymatic reactions with electrons extracted from the photosynthetic electron transport chain. As a proof of concept, we have genetically fused the soluble catalytic domain of the cytochrome P450 CYP79A1, originating from the endoplasmic reticulum membranes of Sorghum bicolor, to a photosystem I subunit in the cyanobacterium Synechococcus sp. PCC 7002, thereby targeting it to the thylakoids. The engineered enzyme showed light-driven activity both in vivo and in vitro, demonstrating the possibility to achieve light-driven biosynthesis of high-value plant specialized metabolites in cyanobacteria.

  7. Anchoring a plant cytochrome P450 via PsaM to the thylakoids in Synechococcus sp. PCC 7002: evidence for light-driven biosynthesis.

    Science.gov (United States)

    Lassen, Lærke Münter; Nielsen, Agnieszka Zygadlo; Olsen, Carl Erik; Bialek, Wojciech; Jensen, Kenneth; Møller, Birger Lindberg; Jensen, Poul Erik

    2014-01-01

    Plants produce an immense variety of specialized metabolites, many of which are of high value as their bioactive properties make them useful as for instance pharmaceuticals. The compounds are often produced at low levels in the plant, and due to their complex structures, chemical synthesis may not be feasible. Here, we take advantage of the reducing equivalents generated in photosynthesis in developing an approach for producing plant bioactive natural compounds in a photosynthetic microorganism by functionally coupling a biosynthetic enzyme to photosystem I. This enables driving of the enzymatic reactions with electrons extracted from the photosynthetic electron transport chain. As a proof of concept, we have genetically fused the soluble catalytic domain of the cytochrome P450 CYP79A1, originating from the endoplasmic reticulum membranes of Sorghum bicolor, to a photosystem I subunit in the cyanobacterium Synechococcus sp. PCC 7002, thereby targeting it to the thylakoids. The engineered enzyme showed light-driven activity both in vivo and in vitro, demonstrating the possibility to achieve light-driven biosynthesis of high-value plant specialized metabolites in cyanobacteria.

  8. Anchoring a Plant Cytochrome P450 via PsaM to the Thylakoids in Synechococcus sp. PCC 7002: Evidence for Light-Driven Biosynthesis

    Science.gov (United States)

    Lassen, Lærke Münter; Nielsen, Agnieszka Zygadlo; Olsen, Carl Erik; Bialek, Wojciech; Jensen, Kenneth; Møller, Birger Lindberg; Jensen, Poul Erik

    2014-01-01

    Plants produce an immense variety of specialized metabolites, many of which are of high value as their bioactive properties make them useful as for instance pharmaceuticals. The compounds are often produced at low levels in the plant, and due to their complex structures, chemical synthesis may not be feasible. Here, we take advantage of the reducing equivalents generated in photosynthesis in developing an approach for producing plant bioactive natural compounds in a photosynthetic microorganism by functionally coupling a biosynthetic enzyme to photosystem I. This enables driving of the enzymatic reactions with electrons extracted from the photosynthetic electron transport chain. As a proof of concept, we have genetically fused the soluble catalytic domain of the cytochrome P450 CYP79A1, originating from the endoplasmic reticulum membranes of Sorghum bicolor, to a photosystem I subunit in the cyanobacterium Synechococcus sp. PCC 7002, thereby targeting it to the thylakoids. The engineered enzyme showed light-driven activity both in vivo and in vitro, demonstrating the possibility to achieve light-driven biosynthesis of high-value plant specialized metabolites in cyanobacteria. PMID:25025215

  9. Saccharomyces cerevisiae YOR071C encodes the high affinity nicotinamide riboside transporter Nrt1.

    Science.gov (United States)

    Belenky, Peter A; Moga, Tiberiu G; Brenner, Charles

    2008-03-28

    NAD(+) is an essential coenzyme for hydride transfer enzymes and a substrate of sirtuins and other NAD(+)-consuming enzymes. Nicotinamide riboside is a recently discovered eukaryotic NAD(+) precursor converted to NAD(+) via the nicotinamide riboside kinase pathway and by nucleosidase activity and nicotinamide salvage. Nicotinamide riboside supplementation of yeast extends replicative life span on high glucose medium. The molecular basis for nicotinamide riboside uptake was unknown in any eukaryote. Here, we show that deletion of a single gene, YOR071C, abrogates nicotinamide riboside uptake without altering nicotinic acid or nicotinamide import. The gene, which is negatively regulated by Sum1, Hst1, and Rfm1, fully restores nicotinamide riboside import and utilization when resupplied to mutant yeast cells. The encoded polypeptide, Nrt1, is a predicted deca-spanning membrane protein related to the thiamine transporter, which functions as a pH-dependent facilitator with a K(m) for nicotinamide riboside of 22 microm. Nrt1-related molecules are conserved in particular fungi, suggesting a similar basis for nicotinamide riboside uptake.

  10. Nicotinamide Riboside and Nicotinic Acid Riboside Salvage in Fungi and Mammals

    Science.gov (United States)

    Belenky, Peter; Christensen, Kathryn C.; Gazzaniga, Francesca; Pletnev, Alexandre A.; Brenner, Charles

    2009-01-01

    NAD+ is a co-enzyme for hydride transfer enzymes and an essential substrate of ADP-ribose transfer enzymes and sirtuins, the type III protein lysine deacetylases related to yeast Sir2. Supplementation of yeast cells with nicotinamide riboside extends replicative lifespan and increases Sir2-dependent gene silencing by virtue of increasing net NAD+ synthesis. Nicotinamide riboside elevates NAD+ levels via the nicotinamide riboside kinase pathway and by a pathway initiated by splitting the nucleoside into a nicotinamide base followed by nicotinamide salvage. Genetic evidence has established that uridine hydrolase, purine nucleoside phosphorylase, and methylthioadenosine phosphorylase are required for Nrk-independent utilization of nicotinamide riboside in yeast. Here we show that mammalian purine nucleoside phosphorylase but not methylthioadenosine phosphorylase is responsible for mammalian nicotinamide riboside kinase-independent nicotinamide riboside utilization. We demonstrate that so-called uridine hydrolase is 100-fold more active as a nicotinamide riboside hydrolase than as a uridine hydrolase and that uridine hydrolase and mammalian purine nucleoside phosphorylase cleave nicotinic acid riboside, whereas the yeast phosphorylase has little activity on nicotinic acid riboside. Finally, we show that yeast nicotinic acid riboside utilization largely depends on uridine hydrolase and nicotinamide riboside kinase and that nicotinic acid riboside bioavailability is increased by ester modification. PMID:19001417

  11. Successful monotherapy of pemphigus vegetans with minocycline and nicotinamide.

    Science.gov (United States)

    von Köckritz, A; Ständer, S; Zeidler, C; Metze, D; Luger, T; Bonsmann, G

    2017-01-01

    Pemphigus vegetans is a rare variant of pemphigus vulgaris, accounting for 1-2% of all pemphigus diseases. Systemic corticosteroids are the therapy of first choice in combination with immunosuppressants as steroid-sparing agents. To highlight the exceptional but successful use of minocycline/nicotinamide monotherapy in pemphigus vegetans. A review of the literature to date about pemphigus vegetans with special emphasis on therapy was performed. Due to its rarity, multiple anecdotal reports without long-term follow-up are available and prospective controlled trials are lacking. Only one retrospective study from Tunisia includes 17 patients with pemphigus vegetans. We present a 76-year-old woman with pemphigus vegetans achieving complete response to a minocycline/nicotinamide monotherapy at onset and at relapse of the disease. Treatment has been discontinued after repeated direct immunofluorescence (DIF) of previously affected normal skin and anti-desmoglein 3 antibodies had become negative. In addition, DIF of previously involved oral mucosa was negative. During long-term follow-up clinical remission has been maintained for more than 5 years. Up to now, negative results of serial performed indirect immunofluorescence and desmoglein ELISA testing also predict immunological remission. In our patient and in a case with oesophageal involvement, published more than 20 years ago, clearly the benefit of minocycline/nicotinamide monotherapy was demonstrated. We propose to consider minocycline/nicotinamide as first-line monotherapy in pemphigus vegetans, especially in elderly patients with comorbidities and contraindications to standard therapy, as it avoids the toxicities of systemic corticosteroids and immunosuppressants. © 2016 European Academy of Dermatology and Venereology.

  12. Transfer of the cytochrome P450-dependent dhurrin pathway from Sorghum bicolor into Nicotiana tabacum chloroplasts for light-driven synthesis

    DEFF Research Database (Denmark)

    Gnanasekaran, Thiyagarajan; Karcher, Daniel; Nielsen, Agnieszka Janina Zygadlo

    2016-01-01

    Plant chloroplasts are light-driven cell factories that have great potential to act as a chassis for metabolic engineering applications. Using plant chloroplasts, we demonstrate how photosynthetic reducing power can drive a metabolic pathway to synthesise a bio-active natural product. For this pu......Plant chloroplasts are light-driven cell factories that have great potential to act as a chassis for metabolic engineering applications. Using plant chloroplasts, we demonstrate how photosynthetic reducing power can drive a metabolic pathway to synthesise a bio-active natural product...

  13. Nicotinamide mononucleotide inhibits JNK activation to reverse Alzheimer disease.

    Science.gov (United States)

    Yao, Zhiwen; Yang, Wenhao; Gao, Zhiqiang; Jia, Peng

    2017-04-24

    Amyloid-β (Aβ) oligomers have been accepted as major neurotoxic agents in the therapy of Alzheimer's disease (AD). It has been shown that the activity of nicotinamide adenine dinucleotide (NAD+) is related with the decline of Aβ toxicity in AD. Nicotinamide mononucleotide (NMN), the important precursor of NAD+, is produced during the reaction of nicotinamide phosphoribosyl transferase (Nampt). This study aimed to figure out the potential therapeutic effects of NMN and its underlying mechanisms in APPswe/PS1dE9 (AD-Tg) mice. We found that NMN gave rise to a substantial improvement in behavioral measures of cognitive impairments compared to control AD-Tg mice. In addition, NMN treatment significantly decreased β-amyloid production, amyloid plaque burden, synaptic loss, and inflammatory responses in transgenic animals. Mechanistically, NMN effectively controlled JNK activation. Furthermore, NMN potently progressed nonamyloidogenic amyloid precursor protein (APP) and suppressed amyloidogenic APP by mediating the expression of APP cleavage secretase in AD-Tg mice. Based on our findings, it was suggested that NMN substantially decreases multiple AD-associated pathological characteristically at least partially by the inhibition of JNK activation. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Preparation and pharmaceutical evaluation of nicotinamide stick for eradication of Staphylococcus epidermidis

    OpenAIRE

    Shahtalebi, Mohammad Ali; Bahrinajafi, Rahim; Nahavandi, Sima

    2014-01-01

    Background: Staphylococcus epidermidis is a part of the skin′s normal flora that can cause acne. This study was designed to evaluate the efficacy of nicotinamide as a stick in eradication of staphylococcus. Materials and Methods: For evaluating of Anti-microbial effect on S. epidermidis used well plate method. We chose five plates for nicotinamide and five for mupirocin. The zones of inhibition were measured and compared. Results: The results showed nicotinamide stick had anti-microbial effec...

  15. Fractionated irradiation combined with carbogen breathing and nicotinamide of two human glioblastomas grafted in nude mice

    OpenAIRE

    SUN, Lin-Quan; BUCHEGGER, Franz; COUCKE, Philippe; MIRIMANOFF

    2001-01-01

    This study addressed the potential radiosensitizing effect of nicotinamide and/or carbogen on human glioblastoma xenografts in nude mice. U-87MG and LN-Z308 tumors were irradiated with either 20 fractions over 12 days or 5 fractions over 5 days in air-breathing mice, mice injected with nicotinamide, mice breathing carbogen, or mice receiving nicotinamide plus carbogen. The responses to treatment were assessed using local control and moist desquamation. In U-87MG tumors, the enhancement ratios...

  16. [The intervention of nicotinamide on skin melanocyte's cell proliferation after UVA (365 nm) exposed.].

    Science.gov (United States)

    Patam, Muhammad; Jin, Xi-peng; Pan, Jian-ying; Shen, Guang-zu; Jin, Tai-Yi

    2005-02-01

    To investigate the interference effect of nicotinamide on UVA-induced cell proliferation in human skin melanocyte. To apply the optimum UVA dose expected to cause cell proliferation: 0.2 cm2, nicotinamide was added after the 0.2 cm2 UVA exposure immediately or 48 h later, then the rate of cell proliferation, calcium concentration and the activities of Na+-K+, Ca2+-ATP enzymes of melanocytes were measured respectively. After treatment with 1.000 mg/ml nicotinamide following UVA exposure, the rate of cell proliferation was decreased significantly 24 hours later. Treatment with 0.125 mg/ml nicotinamide 48 hours after UVA exposure also significantly inhibited the cell proliferation; 1.25 mg/ml nicotinamide increased calcium concentration in cells; 0.250 mg/ml nicotinamide increased the activities of Na+-K+, Ca2+-ATP enzymes in melanocytes (P Nicotinamide has more obvious effect on inhibiting melanocyte's proliferation if added immediately following UVA exposure. Our discovery indicated that nicotinamide may affect the melanocyte through modulating the calcium concentration. It is possible to consider nicotinamide as an efficient and safe sun screen to provide a certain level of protection for UVA exposed skin.

  17. Nicotinamide protects hepatocytes against palmitate-induced lipotoxicity via SIRT1-dependent autophagy induction.

    Science.gov (United States)

    Shen, Chen; Dou, Xiaobing; Ma, Yue; Ma, Wang; Li, Songtao; Song, Zhenyuan

    2017-04-01

    Lipotoxicity induced by saturated fatty acids (SFAs) plays a pathological role in the development of non-alcoholic fatty liver disease (NAFLD); however, the exact mechanism remains to be clearly elucidated. Palmitate is the most abundant SFA in the circulation and major lipotoxic inducer. Accumulating evidence supports that autophagy induction is protective against palmitate-induced cell death in a variety of cell types, including hepatocytes. Nicotinamide is the amide form of nicotinic acid (vitamin B3, Niacin) and a dietary supplementation as a source of vitamin B3. We previously reported that nicotinamide endowed hepatocytes resistance to palmitate-induced ER stress via up-regulating SIRT1, with cAMP/PKA/CREB pathway activation being a fundamental mechanism. This study was undertaken to investigate the potential anti-lipotoxic effect of nicotinamide and to elucidate underlying mechanism(s). Our data demonstrated that nicotinamide supplementation protected hepatocytes against palmitate-induced cell death. Mechanistic investigations revealed that nicotinamide supplementation activated autophagy in hepatocytes. Importantly, we showed that the anti-lipotoxic property of nicotinamide was abolished by autophagy inhibitors, suggesting that autophagy induction plays a mechanistic role in nicotinamide's anti-lipotoxic effect. Furthermore, we showed that SIRT1 inhibition blunted autophagy induction in response to nicotinamide supplementation and similarly abrogated the anti-lipotoxic effect conferred by nicotinamide supplementation. In conclusion, our data suggest that nicotinamide protects against palmitate-induced hepatotoxicity via SIRT1-dependent autophagy induction and that nicotinamide supplementation may represent a therapeutic choice for NAFLD. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Nicotinamide overload may play a role in the development of type 2 diabetes.

    Science.gov (United States)

    Zhou, Shi-Sheng; Li, Da; Sun, Wu-Ping; Guo, Ming; Lun, Yong-Zhi; Zhou, Yi-Ming; Xiao, Fu-Cheng; Jing, Li-Xin; Sun, Shen-Xia; Zhang, Li-Bin; Luo, Ning; Bian, Fu-Ning; Zou, Wei; Dong, Lai-Bin; Zhao, Zhi-Gang; Li, Sheng-Fan; Gong, Xiao-Jie; Yu, Zeng-Guo; Sun, Chang-Bin; Zheng, Cong-Long; Jiang, Dong-Ju; Li, Zheng-Ning

    2009-12-07

    To investigate whether nicotinamide overload plays a role in type 2 diabetes. Nicotinamide metabolic patterns of 14 diabetic and 14 non-diabetic subjects were compared using HPLC. Cumulative effects of nicotinamide and N(1)-methylnicotinamide on glucose metabolism, plasma H(2)O(2) levels and tissue nicotinamide adenine dinucleotide (NAD) contents of adult Sprague-Dawley rats were observed. The role of human sweat glands and rat skin in nicotinamide metabolism was investigated using sauna and burn injury, respectively. Diabetic subjects had significantly higher plasma N(1)-methylnicotinamide levels 5 h after a 100-mg nicotinamide load than the non-diabetic subjects (0.89 +/- 0.13 micromol/L vs 0.6 +/- 0.13 micromol/L, P nicotinamide (2 g/kg) significantly increased rat plasma N(1)-methylnicotinamide concentrations associated with severe insulin resistance, which was mimicked by N(1)-methylnicotinamide. Moreover, cumulative exposure to N(1)-methylnicotinamide (2 g/kg) markedly reduced rat muscle and liver NAD contents and erythrocyte NAD/NADH ratio, and increased plasma H(2)O(2) levels. Decrease in NAD/NADH ratio and increase in H(2)O(2) generation were also observed in human erythrocytes after exposure to N(1)-methylnicotinamide in vitro. Sweating eliminated excessive nicotinamide (5.3-fold increase in sweat nicotinamide concentration 1 h after a 100-mg nicotinamide load). Skin damage or aldehyde oxidase inhibition with tamoxifen or olanzapine, both being notorious for impairing glucose tolerance, delayed N(1)-methylnicotinamide clearance. These findings suggest that nicotinamide overload, which induced an increase in plasma N(1)-methylnicotinamide, associated with oxidative stress and insulin resistance, plays a role in type 2 diabetes.

  19. Session 4: Solid solution sulfide photo-catalysts for hydrogen evolution under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, I.; Kato, H. [Tokyo Univ., Faculty of Science, Dept. of Applied Chemistry (Japan); Kudo, A.; Kobayashi, H. [Kurashiki Univ. of Science and the Arts, (Japan); Kudo, A. [Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (Japan)

    2004-07-01

    In the present study, we tried to make a new visible-light driven photo-catalyst for H{sub 2} evolution by making solid solutions between ZnS photo-catalyst with a wide band gap, and AgInS{sub 2} and CuInS{sub 2} with narrow band gaps. The photophysical and photo-catalytic properties of (MIn){sub x}Zn{sub 2(1-x)}S{sub 2} (M=Cu, Ag) solid solutions were investigated. (authors)

  20. Single-Crystalline Gold Nanowires Synthesized from Light-Driven Oriented Attachment and Plasmon-Mediated Self-Assembly of Gold Nanorods or Nanoparticles

    Science.gov (United States)

    Yu, Shang-Yang; Gunawan, Hariyanto; Tsai, Shiao-Wen; Chen, Yun-Ju; Yen, Tzu-Chen; Liaw, Jiunn-Woei

    2017-03-01

    Through the light-driven geometrically oriented attachment (OA) and self-assembly of Au nanorods (NRs) or nanoparticles (NPs), single-crystalline Au nanowires (NWs) were synthesized by the irradiation of a linearly-polarized (LP) laser. The process was conducted in a droplet of Au colloid on a glass irradiated by LP near-infrared (e.g. 1064 nm and 785 nm) laser beam of low power at room temperature and atmospheric pressure, without any additive. The FE-SEM images show that the cross sections of NWs are various: tetragonal, pentagonal or hexagonal. The EDS spectrum verifies the composition is Au, and the pattern of X-ray diffraction identifies the crystallinity of NWs with the facets of {111}, {200}, {220} and {311}. We proposed a hypothesis for the mechanism that the primary building units are aligned and coalesced by the plasmon-mediated optical torque and force to form the secondary building units. Subsequently, the secondary building units undergo the next self-assembly, and so forth the tertiary ones. The LP light guides the translational and rotational motions of these building units to perform geometrically OA in the side-by-side, end-to-end and T-shaped manners. Consequently, micron-sized ordered mesocrystals are produced. Additionally, the concomitant plasmonic heating causes the annealing for recrystallizing the mesocrystals in water.

  1. Modeling plankton ecosystem functioning and nitrogen fluxes in the oligotrophic waters of the Beaufort Sea, Arctic Ocean: a focus on light-driven processes

    Directory of Open Access Journals (Sweden)

    V. Le Fouest

    2013-07-01

    Full Text Available The Arctic Ocean (AO undergoes profound changes of its physical and biotic environments due to climate change. In some areas of the Beaufort Sea, the stronger haline stratification observed in summer alters the plankton ecosystem structure, functioning and productivity, promoting oligotrophy. A one-dimension (1-D physical–biological coupled model based on the large multiparametric database of the Malina project in the Beaufort Sea was used (i to infer the plankton ecosystem functioning and related nitrogen fluxes and (ii to assess the model sensitivity to key light-driven processes involved in nutrient recycling and phytoplankton growth. The coupled model suggested that ammonium photochemically produced from photosensitive dissolved organic nitrogen (i.e., photoammonification process was a necessary nitrogen source to achieve the observed levels of microbial biomass and production. Photoammonification directly and indirectly (by stimulating the microbial food web activity contributed to 70% and 18.5% of the 0–10 m and whole water column, respectively, simulated primary production (respectively 66% and 16% for the bacterial production. The model also suggested that variable carbon to chlorophyll ratios were required to simulate the observed herbivorous versus microbial food web competition and realistic nitrogen fluxes in the Beaufort Sea oligotrophic waters. In face of accelerating Arctic warming, more attention should be paid in the future to the mechanistic processes involved in food webs and functional group competition, nutrient recycling and primary production in poorly productive waters of the AO, as they are expected to expand rapidly.

  2. Genome-scale modeling of light-driven reductant partitioning and carbon fluxes in diazotrophic unicellular cyanobacterium Cyanothece sp. ATCC 51142.

    Directory of Open Access Journals (Sweden)

    Trang T Vu

    Full Text Available Genome-scale metabolic models have proven useful for answering fundamental questions about metabolic capabilities of a variety of microorganisms, as well as informing their metabolic engineering. However, only a few models are available for oxygenic photosynthetic microorganisms, particularly in cyanobacteria in which photosynthetic and respiratory electron transport chains (ETC share components. We addressed the complexity of cyanobacterial ETC by developing a genome-scale model for the diazotrophic cyanobacterium, Cyanothece sp. ATCC 51142. The resulting metabolic reconstruction, iCce806, consists of 806 genes associated with 667 metabolic reactions and includes a detailed representation of the ETC and a biomass equation based on experimental measurements. Both computational and experimental approaches were used to investigate light-driven metabolism in Cyanothece sp. ATCC 51142, with a particular focus on reductant production and partitioning within the ETC. The simulation results suggest that growth and metabolic flux distributions are substantially impacted by the relative amounts of light going into the individual photosystems. When growth is limited by the flux through photosystem I, terminal respiratory oxidases are predicted to be an important mechanism for removing excess reductant. Similarly, under photosystem II flux limitation, excess electron carriers must be removed via cyclic electron transport. Furthermore, in silico calculations were in good quantitative agreement with the measured growth rates whereas predictions of reaction usage were qualitatively consistent with protein and mRNA expression data, which we used to further improve the resolution of intracellular flux values.

  3. Deracemization of Axially Chiral Nicotinamides by Dynamic Salt Formation with Enantiopure Dibenzoyltartaric Acid (DBTA

    Directory of Open Access Journals (Sweden)

    Fumitoshi Yagishita

    2013-11-01

    Full Text Available Dynamic atroposelective resolution of chiral salts derived from oily racemic nicotinamides and enantiopure dibenzoyltartaric acid (DBTA was achieved by crystallization. The absolute structures of the axial chiral nicotinamides were determined by X-ray structural analysis. The chirality could be controlled by the selection of enantiopure DBTA as a chiral auxiliary. The axial chirality generated by dynamic salt formation was retained for a long period after dissolving the chiral salt in solution even after removal of the chiral acid. The rate of racemization of nicotinamides could be controlled based on the temperature and solvent properties, and that of the salts was prolonged compared to free nicotinamides, as the molecular structure of the pyridinium ion in the salts was different from that of acid-free nicotinamides.

  4. Vitamin B Derivative (Nicotinamide)Appears to Reduce Skin Cancer Risk.

    Science.gov (United States)

    Nazarali, S; Kuzel, P

    2017-09-01

    Nicotinamide, an amide form of vitamin B3, has shown the potential to treat a variety of dermatological conditions, including acne, rosacea, and atopic dermatitis. Recent studies have demonstrated the role of nicotinamide, in both topical and oral forms, as a chemopreventive agent against skin cancer. Its anti-carcinogenic role may be due to its ability to enhance DNA repair and prevent ultraviolet (UV)-induced immunosuppression, which is known to contribute to the progression of pre-malignant lesions. Furthermore, nicotinamide is a precursor of essential coenzymes for many important reactions in the body, including the production of nicotinamide adenine dinucleotide (NAD). NAD is a key coenzyme in the synthesis of adenosine triphosphate (ATP), which transports chemical energy within cells. Therefore, nicotinamide plays a significant role in supporting energy-dependent cellular processes, including DNA repair.

  5. Preparation and pharmaceutical evaluation of nicotinamide stick for eradication of Staphylococcus epidermidis

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Shahtalebi

    2014-01-01

    Full Text Available Background: Staphylococcus epidermidis is a part of the skin′s normal flora that can cause acne. This study was designed to evaluate the efficacy of nicotinamide as a stick in eradication of staphylococcus. Materials and Methods: For evaluating of Anti-microbial effect on S. epidermidis used well plate method. We chose five plates for nicotinamide and five for mupirocin. The zones of inhibition were measured and compared. Results: The results showed nicotinamide stick had anti-microbial effects, but in comparison to mupirocin it was significantly less (P = 0.003. Conclusion: Nicotinamide stick was made and evaluated. This study showed that nicotinamide had anti-microbial effect on staphylococcus.

  6. Pd-doped Bi{sub 2}MoO{sub 6} plasmonic photocatalysts with enhanced visible light photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiangchao, E-mail: xmeng086@uottawa.ca [Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Zhang, Zisheng, E-mail: zzhang@uottawa.ca [Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)

    2017-01-15

    Highlights: • Pd-Bi{sub 2}MoO{sub 6} plamonic photocatalysts were first prepared. • Enhanced visible light-driven photocatalytic performance was observed. • Phenol were completely degraded with Pd-Bi{sub 2}MoO{sub 6} under visible light irradiation. - Abstract: Pd-doped Bi{sub 2}MoO{sub 6} was prepared and investigated for the first time. The prepared samples were characterized by their crystal structures, chemical states, atomic compositions, optical properties and morphologies. The photocatalytic activities of prepared samples under visible light irradiation were determined by degradation of phenol, which is widely found in wastewater from many industrial processes and is difficult to destroy. The sample exhibiting the highest removal efficiency with respect to the degradation of phenol contained 2% Pd. The enhancement effect can be interpreted as the integrated effects of a reduction in the rate of electron-hole recombination, surface plasmon resonance, and production of Cl{sup 0}. This work sheds light on the potential applications of noble metal nanoparticles in visible light-driven photocatalysis.

  7. Nicotinamide riboside, a trace nutrient in foods, is a vitamin B3 with effects on energy metabolism and neuroprotection.

    Science.gov (United States)

    Chi, Yuling; Sauve, Anthony A

    2013-11-01

    This review focuses upon the biology and metabolism of a trace component in foods called nicotinamide riboside. Nicotinamide riboside is a precursor of nicotinamide adenine dinucleotide (NAD), and is a source of Vitamin B3. Evidence indicates that nicotinamide riboside has unique properties as a Vitamin B3. We review knowledge of the metabolism of this substance, as well as recent work suggesting novel health benefits that might be associated with nicotinamide riboside taken in larger quantities than is found naturally in foods. Recent work investigating the effects of nicotinamide riboside in yeast and mammals established that it is metabolized by at least two types of metabolic pathways. The first of these is degradative and produces nicotinamide. The second pathway involves kinases called nicotinamide riboside kinases (Nrk1 and Nrk2, in humans). The likely involvement of the kinase pathway is implicated in the unique effects of nicotinamide riboside in raising tissue NAD concentrations in rodents and for potent effects in eliciting insulin sensitivity, mitochondrial biogenesis, and enhancement of sirtuin functions. Additional studies with nicotinamide riboside in models of Alzheimer's disease indicate bioavailability to brain and protective effects, likely by stimulation of brain NAD synthesis. Initial studies have clarified the potential for a lesser-known Vitamin B3 called nicotinamide riboside that is available in selected foods, and possibly available to humans by supplements. It has properties that are insulin sensitizing, enhancing to exercise, resisting to negative effects of high-fat diet, and neuroprotecting.

  8. Efficient solar light-driven degradation of Congo red with novel Cu-loaded Fe3O4@TiO2 nanoparticles.

    Science.gov (United States)

    Arora, Priya; Fermah, Alisha; Rajput, Jaspreet Kaur; Singh, Harminder; Badhan, Jigyasa

    2017-08-01

    In this work, Cu-loaded Fe3O4@TiO2 core shell nanoparticles were prepared in a single pot by coating of TiO2 on Fe3O4 nanoparticles followed by Cu loading. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), thermogravimetric analysis (TGA), Brunauer-Emmett- Teller (BET), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and valence band X-ray photoelectron spectroscopy (VB XPS) techniques were used for characterization of as prepared nanoparticles. Synergism between copper and titania was evaluated by studying the solar light-driven photodegradation of Congo red dye solution in the presence of Fe3O4@TiO2 nanoparticles on one side and Cu-loaded Fe3O4@TiO2 nanoparticles on the other side. The latter performed better than the former catalyst, indicating the enhanced activity of copper-loaded catalyst. Further photodegradation was studied by three means, i.e., under ultraviolet (UV), refluxing, and solar radiations. Cu-loaded Fe3O4@TiO2 enhanced the degradation efficiency of Congo red dye. Thus, Cu act possibly by reducing the band gap of TiO2 and widening the optical response of semiconductor, as a result of which solar light could be used to carry out photocatalysis. Graphical abstract Photodegradation of congo red over Cu-loaded Fe3O4@TiO2 nanoparticles.

  9. Stable and Flexible CuInS2/ZnS:Al-TiO2 Film for Solar-Light-Driven Photodegradation of Soil Fumigant.

    Science.gov (United States)

    Yan, Lili; Li, Zhichun; Sun, Mingxing; Shen, Guoqing; Li, Liang

    2016-08-10

    Semiconductor quantum dots (QDs) are suitable light absorbers for photocatalysis because of their unique properties. However, QDs generally suffer from poor photochemical stability against air, limiting their applications in photocatalysis. In this study, a stable solar-light-driven QDs-containing photocatalytic film was developed to facilitate photocatalytic degradation of the soil fumigant 1,3-dichloropropene (1,3-D). Highly stable CuInS2/ZnS:Al core/shell QDs (CIS/ZnS:Al QDs) were synthesized by doping Al into the ZnS shell and controlling ZnS:Al shell thickness; the CIS/ZnS:Al QDs were subsequently combined with TiO2 to form a CIS/ZnS:Al-TiO2 photocatalyst. The optimized ZnS:Al shell thickness for 1,3-D photodegradation was approximately 1.3 nm, which guaranteed and balanced the good photocatalytic activity and stability of the CIS/ZnS:Al-TiO2 photocatalyst. The photodegradation efficiency of 1,3-D can be maintained up to more than 80% after five cycles during recycling experiment. When CIS/ZnS:Al-TiO2 was deposited as photocatalytic film on a flexible polyethylene terephthalate substrate, over 99% of cis-1,3-D and 98% of trans-1,3-D were depleted as they passed through the film during 15 h of irradiation under natural solar light. This study demonstrated that the stable CIS/ZnS:Al-TiO2 photocatalyst both in powder and film form is a promising agent for photodegradation and emission reduction of soil fumigants.

  10. Visibly Pushdown Automata

    DEFF Research Database (Denmark)

    Srba, Jiri

    2006-01-01

    We investigate the possibility of (bi)simulation-like preorder/equivalence checking on the class of visibly pushdown automata and its natural subclasses visibly BPA (Basic Process Algebra) and visibly one-counter automata. We describe generic methods for proving complexity upper and lower bounds...... for a number of studied preorders and equivalences like simulation, completed simulation, ready simulation, 2-nested simulation preorders/equivalences and bisimulation equivalence. Our main results are that all the mentioned equivalences and preorders are EXPTIME-complete on visibly pushdown automata, PSPACE......-complete on visibly one-counter automata and P-complete on visibly BPA. Our PSPACE lower bound for visibly one-counter automata improves also the previously known DP-hardness results for ordinary one-counter automata and one-counter nets. Finally, we study regularity checking problems for visibly pushdown automata...

  11. Association of nicotinamide with parabens: effect on solubility, partition and transdermal permeation.

    Science.gov (United States)

    Nicoli, Sara; Zani, Franca; Bilzi, Stefania; Bettini, Ruggero; Santi, Patrizia

    2008-06-01

    Nicotinamide is a hydrophilic molecule, freely soluble in water, used as cosmetic active ingredient for its moisturizing and depigmenting properties. Moreover it has the ability to augment the solubility of poorly water-soluble molecules acting as a hydrotrope. The aim of this work was to study the effect of nicotinamide on the transdermal permeation of methyl, ethyl, propyl and butyl paraben. Parabens flux was measured in vitro in the presence and absence of different amounts of nicotinamide. From solubility studies it was found that nicotinamide forms one or more complexes with methyl, propyl and butyl paraben in water, even though with low stability constants. The interaction of ethyl paraben seems to be less easy to explain. The association of nicotinamide with parabens causes a significant reduction of the permeability coefficients of these preservatives through rabbit ear skin, caused by a reduction of the stratum corneum/vehicle partition coefficient. The effects of nicotinamide on parabens solubility, permeation and partitioning are potentially very interesting because nicotinamide can facilitate paraben dissolution in aqueous media (solutions, gels), reduce parabens partitioning in the oily phase thus guaranteeing an effective concentration in the water phase in emulsion and reduce transdermal penetration, thus reducing the toxicological risk.

  12. The Visibility Complex

    NARCIS (Netherlands)

    Pocchiola, Michel; Vegter, Gert

    1993-01-01

    We introduce the visibility complex of a collection O of n pairwise disjoint convex objects in the plane. This 2–dimensional cell complex may be considered as a generalization of the tangent visibility graph of O. Its space complexity k is proportional to the size of the tangent visibility graph. We

  13. PnuC and the Utilization of the Nicotinamide Riboside Analog 3-Aminopyridine in Haemophilus influenzae

    OpenAIRE

    Sauer, Elizabeta; Merdanovic, Melisa; Price Mortimer, Anne; Bringmann, Gerhard; Reidl, Joachim

    2004-01-01

    The utilization pathway for the uptake of NAD and nicotinamide riboside was previously characterized for Haemophilus influenzae. We now report on the cellular location, topology, and substrate specificity of PnuC. pnuC of H. influenzae is only distantly related to pnuC of Escherichia coli and Salmonella enterica serovar Typhimurium. When E. coli PnuC was expressed in an H. influenzae pnuC mutant, it was able to take up only nicotinamide riboside and not nicotinamide mononucleotide. Therefore,...

  14. Comparison of the effectiveness between 2% and 4% nicotinamide gel in reducing melanin index

    OpenAIRE

    Lisa Murtisari, Lisa Murtisari

    2015-01-01

    Background: Nicotinamide is a safe agent inhibiting melanosome transfer in vitro therefore it can reduce skin pigmentation. Two percent nicotinamide cream combined with sunscreen as a lightening agent in-creases skin lightness in vivo. Measurement of skin colour changes can be performed by mexameter to measure melanin index (MI).Objective: This study was aimed to compare the effectiveness of 2% and 4% nicotinamide gel as a lightening agent in reducing MI.Materials and Methods: This study was ...

  15. Glaucoma as a Metabolic Optic Neuropathy: Making the Case for Nicotinamide Treatment in Glaucoma.

    Science.gov (United States)

    Williams, Pete A; Harder, Jeffrey M; John, Simon W M

    2017-12-01

    Mitochondrial dysfunction may be an important, if not essential, component of human glaucoma. Using transcriptomics followed by molecular and neurobiological techniques, we have recently demonstrated that mitochondrial dysfunction within retinal ganglion cells is an early feature in the DBA/2J mouse model of inherited glaucoma. Guided by these findings, we discovered that the retinal level of nicotinamide adenine dinucleotide (NAD, a key molecule for mitochondrial health) declines in an age-dependent manner. We hypothesized that this decline in NAD renders retinal ganglion cells susceptible to damage during periods of elevated intraocular pressure. To replete NAD levels in this glaucoma, we administered nicotinamide (the amide of vitamin B3). At the lowest dose tested, nicotinamide robustly protected from glaucoma (~70% of eyes had no detectable glaucomatous neurodegeneration). At this dose, nicotinamide had no influence on intraocular pressure and so its effect was neuroprotective. At the highest dose tested, 93% of eyes had no detectable glaucoma. This represents a ~10-fold decrease in the risk of developing glaucoma. At this dose, intraocular pressure still became elevated but there was a reduction in the degree of elevation showing an additional benefit. Thus, nicotinamide is unexpectedly potent at preventing this glaucoma and is an attractive option for glaucoma therapeutics. Our findings demonstrate the promise for both preventing and treating glaucoma by interventions that bolster metabolism during increasing age and during periods of elevated intraocular pressure. Nicotinamide prevents age-related declines in NAD (a decline that occurs in different genetic contexts and species). NAD precursors are reported to protect from a variety of neurodegenerative conditions. Thus, nicotinamide may provide a much needed neuroprotective treatment against human glaucoma. This manuscript summarizes human data implicating mitochondria in glaucoma, and argues for studies to

  16. Structural Basis of Substrate Recognition in Human Nicotinamide N-Methyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Yi; Sartini, Davide; Pozzi, Valentina; Wilk, Dennis; Emanuelli, Monica; Yee, Vivien C. (Case Western); (Politecnica Valencia)

    2012-05-02

    Nicotinamide N-methyltransferase (NNMT) catalyzes the N-methylation of nicotinamide, pyridines, and other analogues using S-adenosyl-L-methionine as donor. NNMT plays a significant role in the regulation of metabolic pathways and is expressed at markedly high levels in several kinds of cancers, presenting it as a potential molecular target for cancer therapy. We have determined the crystal structure of human NNMT as a ternary complex bound to both the demethylated donor S-adenosyl-L-homocysteine and the acceptor substrate nicotinamide, to 2.7 {angstrom} resolution. These studies reveal the structural basis for nicotinamide binding and highlight several residues in the active site which may play roles in nicotinamide recognition and NNMT catalysis. The functional importance of these residues was probed by mutagenesis. Of three residues near the nicotinamide's amide group, substitution of S201 and S213 had no effect on enzyme activity while replacement of D197 dramatically decreased activity. Substitutions of Y20, whose side chain hydroxyl interacts with both the nicotinamide aromatic ring and AdoHcy carboxylate, also compromised activity. Enzyme kinetics analysis revealed k{sub cat}/K{sub m} decreases of 2-3 orders of magnitude for the D197A and Y20A mutants, confirming the functional importance of these active site residues. The mutants exhibited substantially increased K{sub m} for both NCA and AdoMet and modestly decreased k{sub cat}. MD simulations revealed long-range conformational effects which provide an explanation for the large increase in K{sub m}(AdoMet) for the D197A mutant, which interacts directly only with nicotinamide in the ternary complex crystal structure.

  17. Hierarchical CdIn{sub 2}S{sub 4} microspheres wrapped by mesoporous g-C{sub 3}N{sub 4} ultrathin nanosheets with enhanced visible light driven photocatalytic reduction activity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei; Huang, Ting; Hua, Yu-Xiang; Liu, Tian-Yu [Key Laboratory of Education Ministry for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu, Xiao-Heng, E-mail: xhliu@mail.njust.edu.cn [Key Laboratory of Education Ministry for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); Chen, Shen-Ming, E-mail: smchen78@ms15.hinet.net [Electroanalysis and Bioelectrochemistry Lab, Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan, ROC (China)

    2016-12-15

    In this investigation, a series of hierarchical CdIn{sub 2}S{sub 4}/g-C{sub 3}N{sub 4} nanocomposites were firstly synthesized by a facile one-pot hydrothermal strategy, wherein the mesoporous g-C{sub 3}N{sub 4} nanosheets were in-situ self-wrapped onto CdIn{sub 2}S{sub 4} nanosheets. Systematic characterization by XRD, FT-IR, UV-vis DRS, SEM, TEM, HAAF-STEM, XPS, photoelectrochemical tests were employed to analyze the phase structure, chemical composition, morphology and photocatalytic mechanism. The application, including photo-redox reaction and photocatalytic water splitting, were used to estimate the photocatalytic activity of as-obtained CdIn{sub 2}S{sub 4}/g-C{sub 3}N{sub 4} nanocomposites. The results indicate that CdIn{sub 2}S{sub 4}/g-C{sub 3}N{sub 4} heterostructures exhibit more efficient improvement of the photocatalytic performances towards photo-reduction of 4-NA to corresponding 4-PDA and photocatalytic H{sub 2} generation from water splitting than these counterparts as results of construction of intimate interfacial contact, which would promote the separation of photo-generated holes and electrons. Meanwhile, benefitting from the excellent surface wrap, the CdIn{sub 2}S{sub 4}/g-C{sub 3}N{sub 4} nanocomposites possess notable enhanced photocatalytic stability. This research may provide a promising way to fabricate highly efficient photocatalysts with excellent stability and expand the application of CdIn{sub 2}S{sub 4} in fine chemical engineering.

  18. Oil-in-Water Self-Assembled Synthesis of Ag@AgCl Nano-Particles on Flower-like Bi2O2CO3 with Enhanced Visible-Light-Driven Photocatalytic Activity

    OpenAIRE

    Shuanglong Lin; Li Liu; Yinghua Liang; Wenquan Cui; Zisheng Zhang

    2016-01-01

    In this work, a series of novel flower-like Ag@AgCl/Bi2O2CO3 were prepared by simple and feasible oil-in-water self-assembly processes. The phase structures of as-prepared samples were examined by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), X-ray fluorescence spectrometer (XRF), etc. The characterization results indicated that the presence of Ag@AgCl did not affect the crystal structure, bu...

  19. Stimulation of nicotinamide adenine dinucleotide biosynthetic pathways delays axonal degeneration after axotomy.

    Science.gov (United States)

    Sasaki, Yo; Araki, Toshiyuki; Milbrandt, Jeffrey

    2006-08-16

    Axonal degeneration occurs in many neurodegenerative diseases and after traumatic injury and is a self-destructive program independent from programmed cell death. Previous studies demonstrated that overexpression of nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1) or exogenous application of nicotinamide adenine dinucleotide (NAD) can protect axons of cultured dorsal root ganglion (DRG) neurons from degeneration caused by mechanical or neurotoxic injury. In mammalian cells, NAD can be synthesized from multiple precursors, including tryptophan, nicotinic acid, nicotinamide, and nicotinamide riboside (NmR), via multiple enzymatic steps. To determine whether other components of these NAD biosynthetic pathways are capable of delaying axonal degeneration, we overexpressed each of the enzymes involved in each pathway and/or exogenously administered their respective substrates in DRG cultures and assessed their capacity to protect axons after axotomy. Among the enzymes tested, Nmnat1 had the strongest protective effects, whereas nicotinamide phosphoribosyl transferase and nicotinic acid phosphoribosyl transferase showed moderate protective activity in the presence of their substrates. Strong axonal protection was also provided by Nmnat3, which is predominantly located in mitochondria, and an Nmnat1 mutant localized to the cytoplasm, indicating that the subcellular location of NAD production is not crucial for protective activity. In addition, we showed that exogenous application of the NAD precursors that are the substrates of these enzymes, including nicotinic acid mononucleotide, nicotinamide mononucleotide, and NmR, can also delay axonal degeneration. These results indicate that stimulation of NAD biosynthetic pathways via a variety of interventions may be useful in preventing or delaying axonal degeneration.

  20. Nicotinamide and its metabolite N-methylnicotinamide increase skin vascular permeability in rats.

    Science.gov (United States)

    Pietrzak, L; Mogielnicki, A; Buczko, W

    2009-04-01

    It has been suggested that topically applied nicotinamide and its metabolite N-methylnicotinamide (NMN(+)) might be useful agents for treatment of dermatological disorders such as acne vulgaris and rosacea. This study aimed to find out if the mechanism of these therapeutic effects depends on their vascular effects, by investigating if nicotinamide and NMN(+) are able to influence vascular permeability of the vessels in the skin on the back of Wistar rats. A dose-dependent increase in vascular permeability was seen in rats treated intradermally with nicotinamide and NMN(+). Interestingly, a significantly stronger effect of NMN(+) compared with nicotinamide was evident. Increased vascular permeability in rats treated with 0.5% NMN(+) ointment was seen. Moreover, indomethacin, a cyclo-oxygenase 1 and 2 inhibitor and N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, reduced the observed effects of nicotinamide and NMN(+). This study provides direct in vivo evidence that nicotinamide and its metabolite NMN(+) increase skin vascular permeability in rats by a mechanism that may involve NO and prostaglandins.

  1. Oral nicotinamide protects against ultraviolet radiation-induced immunosuppression in humans.

    Science.gov (United States)

    Yiasemides, Eleni; Sivapirabu, Geetha; Halliday, Gary M; Park, Joohong; Damian, Diona L

    2009-01-01

    Cutaneous immunity, which is a key defence against the development of skin cancers, is suppressed by even small doses of ultraviolet (UV) radiation. Preventing this UV-induced immunosuppression may therefore reduce the incidence of skin cancer. Nicotinamide (vitamin B3) has immune-protective and cancer-preventive effects against UV radiation in mice, and we have shown previously that topical nicotinamide is immune protective in humans. Using the Mantoux model of skin immunity in healthy volunteers, we compared oral nicotinamide to placebo (both administered for 1 week) in a randomized, double-blinded, crossover design against the effects of solar-simulated ultraviolet (ssUV) radiation on delayed-type hypersensitivity to tuberculin purified protein derivative. Discrete areas of the back were irradiated with low doses of ssUV daily for three consecutive days. Immunosuppression, calculated as the difference in Mantoux-induced erythema of irradiated sites compared with unirradiated control sites, was determined in volunteers taking oral nicotinamide and placebo. Significant immunosuppression occurred in an UV dose-dependent manner in the presence of placebo. Oral nicotinamide, at doses of either 1500 or 500 mg daily, was well tolerated and significantly reduced UV immunosuppression with no immune effects in unirradiated skin. Oral nicotinamide is safe and inexpensive and looks promising as a chemopreventive supplement for reducing the immunosuppressive effects of sunlight.

  2. Hierarchical visible-light-response Ag/AgCl@TiO2 plasmonic photocatalysts for organic dye degradation

    Science.gov (United States)

    Liu, Wentao; Chen, Deliang; Yoo, Seung Hwa; Cho, Sung Oh

    2013-10-01

    A plasmonic photocatalyst of Ag/AgCl@TiO2 nanoparticles (NPs) was directly prepared by a one-step sonochemical method. Both Ag NPs and AgCl were co-deposited on TiO2 NPs to form Ag@TiO2 and Ag/AgCl@TiO2 using the method. Due to the localized surface plasmonic effects of Ag NPs, the visible-light absorbance of the Ag/AgCl@TiO2 photocatalyst was dramatically increased and the photocatalytic activity to decompose Rhodamine B was much improved under visible light. In addition, due to the advantages of the sonochemical approach, only a very small amount of Ag is required to obtain a high photocatalytic activity in the plasmonic catalyst. The mechanism for the enhancement of the visible-light-driven photocatalytic activities was also analyzed.

  3. Synthesis of surface oxygen-deficient BiPO{sub 4} nanocubes with enhanced visible light induced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Bingtao; Yin, Haoyong; Li, Tao; Gong, Jianying; Lv, Shumei; Nie, Qiulin, E-mail: yhy@hdu.edu.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou (China)

    2017-05-15

    The visible light driven BiPO{sub 4} nanocubes with sufficient surface oxygen deficiency were fabricated by a hydrothermal process and subsequently ultrasonic assistant Fe reduction process. The products were characterized by XRD, DRS, XPS, SEM and TEM which showed that the BiPO{sub 4} had cuboid-like shape with a smooth surface and clear edges and the oxygen vacancies were successfully introduced on the surface of the BiPO{sub 4} nanocubes. The as prepared oxygen-deficient BiPO{sub 4} nanocubes showed greatly enhanced visible light induced photocatalytic activity in degradation of Rhodamine B. The enhanced photocatalytic performance and expanded visible light response of BiPO{sub 4} may be due to the introduction of surface oxygen vacancies which can generate the oxygen vacancies mid-gap states lower to the conduction band of BiPO{sub 4}. (author)

  4. Identification of Isn1 and Sdt1 as Glucose- and Vitamin-regulated Nicotinamide Mononucleotide and Nicotinic Acid Mononucleotide 5′-Nucleotidases Responsible for Production of Nicotinamide Riboside and Nicotinic Acid Riboside*

    OpenAIRE

    Bogan, Katrina L.; Evans, Charles; Belenky, Peter; Song, Peng; Burant, Charles F.; Kennedy, Robert; Brenner, Charles

    2009-01-01

    Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD+, which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast...

  5. Reconstruction of pathway modification induced by nicotinamide using multi-omic network analyses in triple negative breast cancer

    OpenAIRE

    Kim, Ji Young; Lee, Hyebin; Woo, Jongmin; Yue, Wang; Kim, Kwangsoo; Choi, Seongmin; Jang, Ja-June; Kim, Youngsoo; Park, In Ae; Han, Dohyun; Ryu, Han Suk

    2017-01-01

    Triple negative breast cancer (TNBC) is characterized by an aggressive biological behavior in the absence of a specific target agent. Nicotinamide has recently been proven to be a novel therapeutic agent for skin tumors in an ONTRAC trial. We performed combinatory transcriptomic and in-depth proteomic analyses to characterize the network of molecular interactions in TNBC cells treated with nicotinamide. The multi-omic profiles revealed that nicotinamide drives significant functional alteratio...

  6. Viewer Makes Radioactivity "Visible"

    Science.gov (United States)

    Yin, L. I.

    1983-01-01

    Battery operated viewer demonstrates feasibility of generating threedimensional visible light simulations of objects that emit X-ray or gamma rays. Ray paths are traced for two pinhold positions to show location of reconstructed image. Images formed by pinholes are converted to intensified visible-light images. Applications range from radioactivity contamination surveys to monitoring radioisotope absorption in tumors.

  7. Visibility and Citation Impact

    Science.gov (United States)

    Ebrahim, Nader Ale; Salehi, Hadi; Embi, Mohamed Amin; Tanha, Farid Habibi; Gholizadeh, Hossein; Motahar, Seyed Mohammad

    2014-01-01

    The number of publications is the first criteria for assessing a researcher output. However, the main measurement for author productivity is the number of citations, and citations are typically related to the paper's visibility. In this paper, the relationship between article visibility and the number of citations is investigated. A case study of…

  8. Visible Human Project

    Science.gov (United States)

    ... NLM Mobile Gallery Site Navigation Home The Visible Human Project ® Overview The Visible Human Project ® is an outgrowth of the NLM's 1986 ... dimensional representations of the normal male and female human bodies. Acquisition of transverse CT, MR and cryosection ...

  9. Visible light-induced enzymatic hydrogen production from oligosaccharides using Mg chlorophyll-a and platinum colloid conjugate system

    Energy Technology Data Exchange (ETDEWEB)

    Saiki, Yoshinobu; Amao, Yutaka [Oita Univ. (Japan). Dept. of Applied Chemistry

    2004-07-01

    Visible light-induced enzymatic hydrogen production coupling the enzymatic oligosaccharide degradation and hydrogen production with platinum colloid using the photosensitization of Mg chlorophyll-a (Mg Chl-a) has been developed. The continuous hydrogen gas production was observed when the reaction mixture containing oligosaccharide (sucrose or maltose), invertase, glucose dehydrogenase, nicotinamide adenine dinucleotide (NAD{sup +}), Mg Chl-a, methylviologen (MV{sup 2+}, an electron relay reagent) and platinum colloid was irradiated by visible light. After 420 min irradiation, the amounts of hydrogen production from sucrose and from maltose were estimated to be 4.3 and 0.40 {mu}mol, respectively. (Author)

  10. Effect of nicotinamide on early graft failure following intraportal islet transplantation

    Science.gov (United States)

    Jung, Da-Yeon; Park, Jae Berm; Joo, Sung-Yeon; Joh, Jae-Won; Kwon, Choon-Hyuck; Kwon, Ghee-Young

    2009-01-01

    Intraportal islet transplantation (IPIT) may potentially cure Type 1 diabetes mellitus; however, graft failure in the early post-transplantation period presents a major obstacle. In this study, we tested the ability of nicotinamide to prevent early islet destruction in a syngeneic mouse model. Mice (C57BL/6) with chemically-induced diabetes received intraportal transplants of syngeneic islet tissue in various doses. Islets were cultured for 24 h in medium with or without 10 mM nicotinamide supplementation. Following IPIT, islet function was confirmed by an intraperitoneal glucose tolerance test (IPGTT) and hepatectomy. The effects of nicotinamide were evaluated by blood glucose concentration, serum monocyte chemoattractant protein-1 (MCP-1) concentration, and immunohistology at 3 h and 24 h after IPIT. Among the various islet doses, an infusion of 300 syngeneic islets treated with nicotinamide exhibited the greatest differences in glucose tolerance between recipients of treated and untreated (i.e., control) islets. One day after 300 islet equivalent (IEQ) transplantation, islets treated with nicotinamide were better granulated than the untreated islets (P = 0.01), and the recipients displayed a slight decrease in serum MCP-1 concentration, as compared to controls. After 15 days, recipients of nicotinamide-pretreated islets showed higher levels of graft function (as measured by IPGTT) than controls. The pretreatment also prolonged graft survival (> 100 days) and function; these were confirmed by partial hepatectomy, which led to the recurrence of diabetes. Pretreatment of islet grafts with nicotinamide may prevent their deterioration on the early period following IPIT in a syngeneic mouse model. PMID:19641379

  11. Nicotinamide Riboside Opposes Type 2 Diabetes and Neuropathy in Mice.

    Science.gov (United States)

    Trammell, Samuel A J; Weidemann, Benjamin J; Chadda, Ankita; Yorek, Matthew S; Holmes, Amey; Coppey, Lawrence J; Obrosov, Alexander; Kardon, Randy H; Yorek, Mark A; Brenner, Charles

    2016-05-27

    Male C57BL/6J mice raised on high fat diet (HFD) become prediabetic and develop insulin resistance and sensory neuropathy. The same mice given low doses of streptozotocin are a model of type 2 diabetes (T2D), developing hyperglycemia, severe insulin resistance and diabetic peripheral neuropathy involving sensory and motor neurons. Because of suggestions that increased NAD(+) metabolism might address glycemic control and be neuroprotective, we treated prediabetic and T2D mice with nicotinamide riboside (NR) added to HFD. NR improved glucose tolerance, reduced weight gain, liver damage and the development of hepatic steatosis in prediabetic mice while protecting against sensory neuropathy. In T2D mice, NR greatly reduced non-fasting and fasting blood glucose, weight gain and hepatic steatosis while protecting against diabetic neuropathy. The neuroprotective effect of NR could not be explained by glycemic control alone. Corneal confocal microscopy was the most sensitive measure of neurodegeneration. This assay allowed detection of the protective effect of NR on small nerve structures in living mice. Quantitative metabolomics established that hepatic NADP(+) and NADPH levels were significantly degraded in prediabetes and T2D but were largely protected when mice were supplemented with NR. The data justify testing of NR in human models of obesity, T2D and associated neuropathies.

  12. Investigation of different emulsion systems for dermal delivery of nicotinamide.

    Science.gov (United States)

    Tuncay, Sakine; Özer, Özgen

    2013-01-01

    Nicotinamide (NA) has been shown to have beneficial effects on several skin diseases such as tumor, acne vulgaris, photodamage, cellulite and atopic dermatitis. The purpose of this study was to develop a multiple emulsion and a microemulsion formulation as delivery systems for NA. A two-step process was used to prepare the W/O/W multiple emulsion. Optimum microemulsion formulation was selected by using construction of pseudo-ternary phase diagram. The physicochemical properties such as droplet size and viscosity measurements, stability studies were also evaluated. Ex-vivo permeation studies were performed with Franz-type diffusion cells and the samples were analysed by high performance liquid chromatography (HPLC). The permeation data showed that there was no significant difference between multiple emulsion and microemulsion (p > 0.05). Transepidermal water loss (TEWL) was also measured. As a result of TEWL studies, a slight increase of TEWL values was observed for microemulsion formulation on rat skin when compared with multiple emulsion and commercial formulation. The results suggested that microemulsion and multiple emulsion formulations could be new and alternative dosage forms for topical application of NA.

  13. Fabrication of PAN@TiO2/Ag nanofibrous membrane with high visible light response and satisfactory recyclability for dye photocatalytic degradation

    Science.gov (United States)

    Shi, Yongzheng; Yang, Dongzhi; Li, Yuan; Qu, Jin; Yu, Zhong-Zhen

    2017-12-01

    Although TiO2-based photocatalysts have exhibited a great potential for degradation of organic pollutants, it is still necessary to simultaneously enhance their visible-light-driven photocatalytic efficiency and physical recyclability. Herein, highly efficient, visible-light-driven photocatalytically active, and recyclable nanofibrous membranes with thin TiO2/Ag heterojunction layer are prepared using electrospun polyacrylonitrile (PAN) nanofibrous membrane as the substrate. By regulating the concentration and hydrolysis process of Ti precursors, TiO2 nanoparticles steadily grow on the PAN nanofibers with high-specific surface area to form a continuous mesoporous shell with the thickness of 20 nm for efficient degradation of organic pollutants. Furthermore, to form a stable heterojunction structure, Ag nanoparticles are deposited on the TiO2 surface by using dopamine as a binder and reductant. The presence of Ag nanoparticles leads to an obvious red-shift from 380 nm to 490 nm, which improves the utilization efficiency of visible light, and reduces the electron/hole recombination rate simultaneously. The resulting PAN@TiO2/Ag membranes hold enhanced photocatalytic activity for methylene blue degradation within 1 h under visible light irradiation, and satisfactory recyclability, which endow them with a great potential for adsorption and photocatalytic applications.

  14. Environmental remediation and superhydrophilicity of ultrafine antibacterial tungsten oxide-based nanofibers under visible light source

    Energy Technology Data Exchange (ETDEWEB)

    Srisitthiratkul, Chutima; Yaipimai, Wittaya [Nano Functional Textile Laboratory, National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Intasanta, Varol, E-mail: varol@nanotec.or.th [Nano Functional Textile Laboratory, National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand)

    2012-10-15

    Graphical abstract: Nanosilver-decorated WO{sub 3} photocatalytic nanofibers are antibacterial and superhydrophilic under a visible light source. Highlights: Black-Right-Pointing-Pointer Deposition of nanosilver onto electrospun WO{sub 3} nanofibers' surface was done exploiting visible or UV light driven photoreduction of silver ion. Black-Right-Pointing-Pointer Nanofibers showed antibacterial characteristics. Black-Right-Pointing-Pointer Nanofibers degraded a model toxin effectively. Black-Right-Pointing-Pointer Nanofibers showed superhydrophilicity under a visible light source. - Abstract: Fabrication of nanosilver-decorated WO{sub 3} nanofibers was successfully performed. First, deposition of nanosilver onto electrospun WO{sub 3} nanofibers' surface was done via photoreduction of silver ion under visible or UV light. The resulting hybrid nanofibers not only revealed antibacterial characteristics but also maintained their photocatalytic performance towards methylene blue decomposition. Unexpectedly, the nanofibrous layers prepared from these nanofibers showed superhydrophilicity under a visible light source. The nanofibers might be advantageous in environmental and hygienic nanofiltration under natural light sources, where the self-cleaning characteristics could be valuable in maintenance processes.

  15. Au/ZnO nanoarchitectures with Au as both supporter and antenna of visible-light

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Tianyu; Chen, Wei; Hua, Yuxiang; Liu, Xiaoheng, E-mail: xhliu@mail.njust.edu.cn

    2017-01-15

    Highlights: • An inversed Au/ZnO nanostructure was fabricated with ZnO loaded onto Au. • The Au/ZnO nanocomposites showed enhanced properties in visible-light photocatalysis. • The SPR effect of Au was considered important for visible-light photocatalysis. - Abstract: In this paper, we fabricate Au/ZnO nanostructure with smaller ZnO nanoparticles loaded onto bigger gold nanoparticles via combining seed-mediated method and sol-gel method. The obtained Au/ZnO nanocomposites exhibit excellent properties in photocatalysis process like methyl orange (MO) degradation and oxidative conversion of methanol into formaldehyde under visible light irradiation. The enhanced properties were ascribed to the surface plasmon resonance (SPR) effect of Au nanoparticles, which could contribute to the separation of photo-excited electrons and holes and facilitate the process of absorbing visible light. This paper contributes to the emergence of multi-functional nanocomposites with possible applications in visible-light driven photocatalysts and makes the Au/ZnO photocatalyst an exceptional choice for practical applications such as environmental purification of organic pollutants in aqueous solution and the synthesis of fine chemicals and intermediates.

  16. Nicotinamide enhances repair of ultraviolet radiation-induced DNA damage in human keratinocytes and ex vivo skin.

    Science.gov (United States)

    Surjana, Devita; Halliday, Gary M; Damian, Diona L

    2013-05-01

    Nicotinamide (vitamin B3) protects from ultraviolet (UV) radiation-induced carcinogenesis in mice and from UV-induced immunosuppression in mice and humans. Recent double-blinded randomized controlled Phase 2 studies in heavily sun-damaged individuals have shown that oral nicotinamide significantly reduces premalignant actinic keratoses, and may reduce new non-melanoma skin cancers. Nicotinamide is a precursor of nicotinamide adenine dinucleotide (NAD(+)), an essential coenzyme in adenosine triphosphate (ATP) production. Previously, we showed that nicotinamide prevents UV-induced ATP decline in HaCaT keratinocytes. Energy-dependent DNA repair is a key determinant of cellular survival after exposure to DNA-damaging agents such as UV radiation. Hence, in this study we investigated whether nicotinamide protection from cellular energy loss influences DNA repair. We treated HaCaT keratinocytes with nicotinamide and exposed them to low-dose solar-simulated UV (ssUV). Excision repair was quantified using an assay of unscheduled DNA synthesis. Nicotinamide increased both the proportion of cells undergoing excision repair and the repair rate in each cell. We then investigated ssUV-induced cyclobutane pyrimidine dimers (CPDs) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxoG) formation and repair by comet assay in keratinocytes and with immunohistochemistry in human skin. Nicotinamide reduced CPDs and 8oxoG in both models and the reduction appeared to be due to enhancement of DNA repair. These results show that nicotinamide enhances two different pathways for repair of UV-induced photolesions, supporting nicotinamide's potential as an inexpensive, convenient and non-toxic agent for skin cancer chemoprevention.

  17. PnuC and the utilization of the nicotinamide riboside analog 3-aminopyridine in Haemophilus influenzae.

    Science.gov (United States)

    Sauer, Elizabeta; Merdanovic, Melisa; Mortimer, Anne Price; Bringmann, Gerhard; Reidl, Joachim

    2004-12-01

    The utilization pathway for the uptake of NAD and nicotinamide riboside was previously characterized for Haemophilus influenzae. We now report on the cellular location, topology, and substrate specificity of PnuC. pnuC of H. influenzae is only distantly related to pnuC of Escherichia coli and Salmonella enterica serovar Typhimurium. When E. coli PnuC was expressed in an H. influenzae pnuC mutant, it was able to take up only nicotinamide riboside and not nicotinamide mononucleotide. Therefore, we postulated that PnuC transporters in general possess specificity for nicotinamide riboside. Earlier studies showed that 3-aminopyridine derivatives (e.g., 3-aminopyridine adenine dinucleotide) are inhibitory for H. influenzae growth. By testing characterized strains with mutations in the NAD utilization pathway, we show that 3-aminopyridine riboside is inhibitory to H. influenzae and is taken up by the NAD-processing and nicotinamide riboside route. 3-Aminopyridine riboside is utilized effectively in a pnuC+ background. In addition, we demonstrate that 3-aminopyridine adenine dinucleotide resynthesis is produced by NadR. 3-Aminopyridine riboside-resistant H. influenzae isolates were characterized, and mutations in nadR could be detected. We also tested other species of the family Pasteurellaceae, Pasteurella multocida and Actinobacillus actinomycetemcomitans, and found that 3-aminopyridine riboside does not act as a growth inhibitor; hence, 3-aminopyridine riboside represents an anti-infective agent with a very narrow host range.

  18. Meat and Nicotinamide: A Causal Role in Human Evolution, History, and Demographics

    Directory of Open Access Journals (Sweden)

    Adrian C Williams

    2017-04-01

    Full Text Available Hunting for meat was a critical step in all animal and human evolution. A key brain-trophic element in meat is vitamin B 3 /nicotinamide. The supply of meat and nicotinamide steadily increased from the Cambrian origin of animal predators ratcheting ever larger brains. This culminated in the 3-million-year evolution of Homo sapiens and our overall demographic success. We view human evolution, recent history, and agricultural and demographic transitions in the light of meat and nicotinamide intake. A biochemical and immunological switch is highlighted that affects fertility in the ‘de novo’ tryptophan-to-kynurenine-nicotinamide ‘immune tolerance’ pathway. Longevity relates to nicotinamide adenine dinucleotide consumer pathways. High meat intake correlates with moderate fertility, high intelligence, good health, and longevity with consequent population stability, whereas low meat/high cereal intake (short of starvation correlates with high fertility, disease, and population booms and busts. Too high a meat intake and fertility falls below replacement levels. Reducing variances in meat consumption might help stabilise population growth and improve human capital.

  19. Pharmacologic doses of nicotinamide in the treatment of inflammatory skin conditions: a review.

    Science.gov (United States)

    Niren, Neil M

    2006-01-01

    Various skin disorders with an inflammatory component often have been treated with steroids and/or oral antibiotics. However, long-term use of these agents has drawbacks: steroids may induce numerous serious side effects such as hypertension, immunosuppression, and osteoporosis, and overuse of oral antibiotics may contribute to the development of bacterial resistance, as well as to a host of nuisance side effects such as diarrhea, yeast infections, and photosensitivity. As a result, alternative oral treatments, such as nicotinamide, have been investigated. During the past 50 years, many clinical reports have identified nicotinamide as a beneficial agent in the treatment of a variety of inflammatory skin disorders; what's more, its exceptional safety profile at pharmacologic doses makes it a potentially ideal long-term oral therapy for patients with inflammatory skin diseases. A recent large study evaluating nicotinamide for the treatment of acne or rosacea has confirmed the potential benefits of oral nicotinamide as an alternative approach to managing inflammatory lesions associated with acne vulgaris and acne rosacea. This article reviews the substantial number of reports published over the past 50 years that document the clinical utility and safety of oral and topical formulations of nicotinamide for the treatment of a variety of inflammatory skin conditions.

  20. UV radiation-induced immunosuppression is greater in men and prevented by topical nicotinamide.

    Science.gov (United States)

    Damian, Diona L; Patterson, Clare R S; Stapelberg, Michael; Park, Joohong; Barnetson, Ross St C; Halliday, Gary M

    2008-02-01

    UV radiation-induced immunosuppression augments cutaneous carcinogenesis. The incidence of skin cancer continues to increase despite increased use of sunscreens, which are less effective at preventing immunosuppression than sunburn. Using the Mantoux reaction as a model of skin immunity, we investigated the effects of solar-simulated (ss) UV and its component UVA and UVB wavebands and tested the ability of topical nicotinamide to protect from UV-induced immunosuppression. Healthy, Mantoux-positive volunteers were UV-irradiated on their backs, with 5% nicotinamide or vehicle applied to different sites in a randomized, double-blinded manner. Subsequent Mantoux testing at irradiated and adjacent unirradiated sites enabled measurement of UV-induced immunosuppression with and without nicotinamide. Suberythemal ssUV caused significant immunosuppression, although component UVB and UVA doses delivered independently did not. Men were immunosuppressed by ssUV doses three times lower than those required to immunosuppress women. This may be an important cause of the higher skin cancer incidence and mortality observed in men. Topical nicotinamide prevented immunosuppression, with gene chip microarrays suggesting that the mechanisms of protection may include alterations in complement, energy metabolism and apoptosis pathways. Nicotinamide is a safe and inexpensive compound that could be added to sunscreens or after-sun lotions to improve protection from immunosuppression. immunosuppression.JID JOURNAL CLUB ARTICLE: For questions, answers, and open discussion about this article, please go to http://network.nature.com/group/jidclub

  1. Nicotinamide enhances repair of ultraviolet radiation-induced DNA damage in primary melanocytes.

    Science.gov (United States)

    Thompson, Benjamin C; Surjana, Devita; Halliday, Gary M; Damian, Diona L

    2014-07-01

    Cutaneous melanoma is a significant cause of morbidity and mortality. Nicotinamide is a safe, widely available vitamin that reduces the immune suppressive effects of UV, enhances DNA repair in keratinocytes and has shown promise in the chemoprevention of non-melanoma skin cancer. Here, we report the effect of nicotinamide on DNA damage and repair in primary human melanocytes. Nicotinamide significantly enhanced the repair of oxidative DNA damage (8-oxo-7,8-dihydro-2'-deoxyguanosine) and cyclobutane pyrimidine dimers induced by UV exposure. It also enhanced the repair of 8-oxo-7,8-dihydro-2'-deoxyguanosine induced by the culture conditions in unirradiated melanocytes. A significant increase in the percentage of melanocytes undergoing unscheduled but not scheduled DNA synthesis was observed, confirming that nicotinamide enhances DNA repair in human melanocytes. In summary, nicotinamide, by enhancing DNA repair in melanocytes, is a potential agent for the chemoprevention of cutaneous melanoma. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Inhibitory effect of nicotinamide on enzymatic activity of selected fungal strains causing skin infection.

    Science.gov (United States)

    Ciebiada-Adamiec, Anna; Małafiej, Eugeniusz; Ciebiada, Ireneusz

    2010-05-01

    Pathogenicity of fungi is connected with their ability to easily penetrate the host tissues, survive in the infected host organism and use the elements of the host tissues as nutrients. Hence, the co-occurrence of pathogenic properties with the high enzymatic activity, which is manifested through the production of various enzymes including extracellular enzymes, was observed. It can be expected that it is possible to decrease fungal pathogenicity by lowering their enzymatic activity. The aim of the study was to determine the effect of nicotinamide on enzymatic activity of the fungi, which are most frequently isolated in cases of skin infection. Enzymatic activity was analysed using 15 Candida albicans, 15 Trichophyton rubrum and 15 Trichophyton mentagrophytes strains. The strains used for the study were collected from the current diagnostic material. API ZYM tests were used in diagnostic analysis. MICs of nicotinamide were determined by the macrodilution method in liquid medium. In the case of Candida strains, the presence of nicotinamide in the broth had a significant effect on the decrease of enzymatic activity (P nicotinamide was observed in the case of dermatophytes (P nicotinamide exhibited biological activity towards C. albicans, T. rubrum and Trichophyton mentagrophytes, which resulted in a decrease in the activity of enzymes produced by the fungi.

  3. Intervention with nicotinamide in pre-type 1 diabetes: the Deutsche Nikotinamid Interventionsstudie-DENIS.

    Science.gov (United States)

    Lampeter, E F

    1993-01-01

    Nicotinamide is a prime candidate for clinical trials on preventing Type 1 diabetes. It is thought to protect Beta-cells mainly by increasing intracellular NADP levels via competitive inhibition of poly-(ADP-ribose)-polymerase. Thus, since nicotinamide protects target cells while under autoimmune attack it should be used at a time when sufficient numbers of beta-cells are still present, i.e. in the early stages of diabetes development. Increased diabetes risk can be identified by the presence of islet cell antibodies (ICA) and an increasing number of other more or less well defined antibodies in relatives of Type 1 diabetic patients. However, ICA is the best-evaluated marker and was therefore chosen for initial screening. The aim of the German Nicotinamide Intervention Study (DENIS) is to evaluate the potency of nicotinamide at protecting children with an increased risk of Type 1 diabetes from manifestation of the disease. The trial is placebo-controlled and double-blinded. A sustained-release preparation of nicotinamide is given at a dose of 1.2 g/m2 body surface. Entry criteria: ICA > or = 20 JDF units (at least two positive readings within 6 months, > or = 3 months apart, one measurement > or = 20 JDF units); siblings of Type 1 diabetic patients, 3-12 years of age; IVGTT performed. diabetes according to WHO criteria (including abnormal OGTT); no written consent; other chronic diseases. Definition of endpoint: Diabetes according to WHO criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Nicotinamide riboside promotes Sir2 silencing and extends lifespan via Nrk and Urh1/Pnp1/Meu1 pathways to NAD+.

    Science.gov (United States)

    Belenky, Peter; Racette, Frances G; Bogan, Katrina L; McClure, Julie M; Smith, Jeffrey S; Brenner, Charles

    2007-05-04

    Although NAD(+) biosynthesis is required for Sir2 functions and replicative lifespan in yeast, alterations in NAD(+) precursors have been reported to accelerate aging but not to extend lifespan. In eukaryotes, nicotinamide riboside is a newly discovered NAD(+) precursor that is converted to nicotinamide mononucleotide by specific nicotinamide riboside kinases, Nrk1 and Nrk2. In this study, we discovered that exogenous nicotinamide riboside promotes Sir2-dependent repression of recombination, improves gene silencing, and extends lifespan without calorie restriction. The mechanism of action of nicotinamide riboside is totally dependent on increased net NAD(+) synthesis through two pathways, the Nrk1 pathway and the Urh1/Pnp1/Meu1 pathway, which is Nrk1 independent. Additionally, the two nicotinamide riboside salvage pathways contribute to NAD(+) metabolism in the absence of nicotinamide-riboside supplementation. Thus, like calorie restriction in the mouse, nicotinamide riboside elevates NAD(+) and increases Sir2 function.

  5. Synthesis of visibility detection systems.

    Science.gov (United States)

    2012-10-01

    Visibility is a critical component to the task of driving on all types of roads. The visibility detection and warning systems provide real-time, automated detection as well as appropriate responses to counteract reduced visibility conditions due to f...

  6. Photosensitized oxidation of nicotinamide adenine dinucleotide by diethoxyphosphorus(V)tetraphenylporphyrin and its fluorinated derivative: Possibility of chain reaction

    Science.gov (United States)

    Hirakawa, Kazutaka; Murata, Atsushi

    2018-01-01

    Water-soluble porphyrins, diethoxyphosphorus(V)tetraphenylporphyrin (EtP(V)TPP) and its fluorinated analogue (FEtP(V)TPP), decreased the typical absorption around 340 nm of nicotinamide adenine dinucleotide (NADH) under visible light irradiation, indicating oxidative decomposition. A singlet oxygen quencher, sodium azide, and a triplet quencher, potassium iodide, slightly inhibited photosensitized NADH oxidation. However, these inhibitory effects were very small. Furthermore, the fluorescence lifetime of these P(V)porphyrins was decreased by NADH, suggesting the contribution of electron transfer to the singlet excited (S1) state of P(V)porphyrin. The redox potential measurement supports the electron transfer-mediated oxidation of NADH. The quantum yields of NADH photodecomposition by P(V)porphyrins could be estimated from the kinetic data and the effect of these quenchers on NADH oxidation. The obtained values suggest that the electron accepting by the S1 states of P(V)porphyrins triggers a chain reaction of NADH oxidation. This photosensitized reaction may play an important role in the photocytotoxicity of P(V)porphyrins. The axial ligand fluorination of P(V)porphyrins improved electron accepting ability. However, fluorination slightly suppressed static interaction with NADH, resulting in decreased oxidation quantum yield.

  7. Photosensitized oxidation of nicotinamide adenine dinucleotide by diethoxyphosphorus(V)tetraphenylporphyrin and its fluorinated derivative: Possibility of chain reaction.

    Science.gov (United States)

    Hirakawa, Kazutaka; Murata, Atsushi

    2018-01-05

    Water-soluble porphyrins, diethoxyphosphorus(V)tetraphenylporphyrin (EtP(V)TPP) and its fluorinated analogue (FEtP(V)TPP), decreased the typical absorption around 340nm of nicotinamide adenine dinucleotide (NADH) under visible light irradiation, indicating oxidative decomposition. A singlet oxygen quencher, sodium azide, and a triplet quencher, potassium iodide, slightly inhibited photosensitized NADH oxidation. However, these inhibitory effects were very small. Furthermore, the fluorescence lifetime of these P(V)porphyrins was decreased by NADH, suggesting the contribution of electron transfer to the singlet excited (S1) state of P(V)porphyrin. The redox potential measurement supports the electron transfer-mediated oxidation of NADH. The quantum yields of NADH photodecomposition by P(V)porphyrins could be estimated from the kinetic data and the effect of these quenchers on NADH oxidation. The obtained values suggest that the electron accepting by the S1 states of P(V)porphyrins triggers a chain reaction of NADH oxidation. This photosensitized reaction may play an important role in the photocytotoxicity of P(V)porphyrins. The axial ligand fluorination of P(V)porphyrins improved electron accepting ability. However, fluorination slightly suppressed static interaction with NADH, resulting in decreased oxidation quantum yield. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. The mechanisms of action of nicotinamide and zinc in inflammatory skin disease.

    Science.gov (United States)

    Fivenson, David P

    2006-01-01

    Nicotinamide (niacinamide), a physiologically active form of niacin (nicotinic acid), in combination with zinc is being assessed in clinical studies for the treatment of inflammatory skin diseases such as acne vulgaris and bullous pemphigoid. The basis for these investigations is the variety of potential mechanisms of action of nicotinamide and zinc, including an anti-inflammatory effect via inhibition of leukocyte chemotaxis, lysosomal enzyme release, lymphocytic transformation, mast cell degranulation, bacteriostatic effect against Propionibacterium acnes, inhibition of vasoactive amines, preservation of intracellular coenzyme homeostasis, and decreased sebum production. Other possible mechanisms involve suppression of vascular permeability and inflammatory cell accumulation, as well as protection against DNA damage. The goal of this paper is to review the pathophysiology of inflammatory skin diseases and discuss the role, mechanisms of action, and safety of nicotinamide and zinc as therapeutic options for these disorders.

  9. Solubility enhancement of some water-insoluble drugs in the presence of nicotinamide and related compounds.

    Science.gov (United States)

    Rasool, A A; Hussain, A A; Dittert, L W

    1991-04-01

    The solubilities of five poorly water-soluble drugs, diazepam, griseofulvin, progesterone, 17 beta-estradiol, and testosterone, were studied in the presence of nicotinamide. All solubilities were found to increase in a nonlinear fashion as a function of nicotinamide concentration. The K1:1 and K1:2 stability constants were as follows: for diazepam, K1:1 = 5.23 M-1 and K1:2 = 8.6 M-2; for griseofulvin, K1:1 = 5.54 M-1 and K1:2 = 8.82 M-2; for progesterone, K1:1 = 5.48 M-1 and K1:2 = 42.47 M-2; for 17 beta-estradiol, K1:1 = 5.38 M-1 and K1:2 = 36.9 M-2; and for testosterone, K1:1 = 5.07 M-1 and K1:2 = 27.47 M-2. Two aliphatic analogues of nicotinamide (nipecotamide and N,N-dimethylacetamide) were studied as ligands with diazepam and griseofulvin and were found to increase the solubilities of both drugs in a linear fashion. The aromatic analogue, N,N-diethylnicotinamide, showed a nonlinear solubilization relationship similar to that seen with nicotinamide. In addition, three other aromatic analogues (isonicotinamide, 1-methylnicotinamide iodide, and N-methylnicotinamide) were studied. These ligands were not soluble enough in water to be studied over the wide range of concentrations used for nicotinamide and N,N-diethylnicotinamide; however, in the concentration range studied, these ligands solubilized diazepam and griseofulvin to a degree similar to that observed with comparable concentrations of nicotinamide. These results suggest that the aromaticity (Pi-system) of the pyridine ring is an important factor in complexation because the aromatic amide ligands were found to enhance the aqueous solubilities of the test drugs to a greater extent than the aliphatic amide ligands.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Topical 4% nicotinamide vs. 1% clindamycin in moderate inflammatory acne vulgaris.

    Science.gov (United States)

    Khodaeiani, Effat; Fouladi, Rohollah Fadaei; Amirnia, Mehdi; Saeidi, Majid; Karimi, Elham Razagh

    2013-08-01

    Nicotinamide and clindamycin gels are two popular topical medications for acne vulgaris. This study aimed to compare efficacy of the topical 4% nicotinamide and 1% clindamycin gels in these patients. In this randomized, double-blind clinical trial, patients with moderate inflammatory facial acne vulgaris were randomly allocated to receive either topical 4% nicotinamide (n = 40) or 1% clindamycin gels (n = 40) twice daily. In each group, they were further categorized in two subgroups with oily and non-oily types of facial skin. The Cook's acne grade was determined at baseline and at weeks 4 and 8 post treatment. Acne grade decreased from an average of 5.93 ± 0.83 at baseline to 4.03 ± 1.33 at week 4 and 2.08 ± 1.59 at week 8 in nicotinamide receivers, and from an average of 5.70 ± 0.94 at baseline to 3.85 ± 1.66 at week 4 and 2.03 ± 1.53 at week 8 in the clindamycin group (within-group P  0.05). Comparing with each other, nicotinamide and clindamycin gels were significantly more efficacious in oily and non-oily skin types, respectively. No major side effect was encountered by any patient. Skin type is a significant factor in choosing between topical nicotinamide and clindamycin in patients with acne vulgaris. © 2013 The International Society of Dermatology.

  11. Nicotinamide inhibits vasculogenic mimicry, an alternative vascularization pathway observed in highly aggressive melanoma.

    Directory of Open Access Journals (Sweden)

    Orit Itzhaki

    Full Text Available Vasculogenic mimicry (VM describes functional vascular channels composed only of tumor cells and its presence predicts poor prognosis in melanoma patients. Inhibition of this alternative vascularization pathway might be of clinical importance, especially as several anti-angiogenic therapies targeting endothelial cells are largely ineffective in melanoma. We show the presence of VM structures histologically in a series of human melanoma lesions and demonstrate that cell cultures derived from these lesions form tubes in 3D cultures ex vivo. We tested the ability of nicotinamide, the amide form of vitamin B3 (niacin, which acts as an epigenetic gene regulator through unique cellular pathways, to modify VM. Nicotinamide effectively inhibited the formation of VM structures and destroyed already formed ones, in a dose-dependent manner. Remarkably, VM formation capacity remained suppressed even one month after the complete withdrawal of Nicotimamid. The inhibitory effect of nicotinamide on VM formation could be at least partially explained by a nicotinamide-driven downregulation of vascular endothelial cadherin (VE-Cadherin, which is known to have a central role in VM. Further major changes in the expression profile of hundreds of genes, most of them clustered in biologically-relevant clusters, were observed. In addition, nicotinamide significantly inhibited melanoma cell proliferation, but had an opposite effect on their invasion capacity. Cell cycle analysis indicated moderate changes in apoptotic indices. Therefore, nicotinamide could be further used to unravel new biological mechanisms that drive VM and tumor progression. Targeting VM, especially in combination with anti-angiogenic strategies, is expected to be synergistic and might yield substantial anti neoplastic effects in a variety of malignancies.

  12. The efficacy of nicotinamide gel 4% as an adjuvant therapy in the treatment of cutaneous erosions of pemphigus vulgaris.

    Science.gov (United States)

    Iraji, Fariba; Banan, Laleh

    2010-01-01

    The high rate of morbidity and mortality resulting from long-term use of corticosteroids in pemphigus vulgaris (PV) warrants discovery of a new treatment strategy. Based on the pathophysiology of PV, nicotinamide can block the process of blister formation through its anti-inflammatory properties. This study was conducted to evaluate the clinical effectiveness of nicotinamide gel in the treatment of skin lesions of PV. In a double-blind, placebo-controlled study, eight PV patients with a total of 60 skin lesions were treated by either nicotinamide or placebo gel. After 30 days of treatment, epithelialization index of the two groups was compared. The mean of the epithelialization index in skin lesions that received nicotinamide was significantly higher than that of the placebo group (26 vs. -5.8, p nicotinamide gel can effectively be used as an adjunctive treatment for PV lesions.

  13. Application of a coupled enzyme assay to characterize nicotinamide riboside kinases.

    Science.gov (United States)

    Dölle, Christian; Ziegler, Mathias

    2009-02-15

    The recently identified nicotinamide riboside kinases (Nrks) constitute a distinct pathway of nicotinamide adenine dinucleotide (NAD) biosynthesis. Here we present the combination of an established optical adenosine triphosphatase (ATPase) test, the pyruvate kinase/lactate dehydrogenase system, with the Nrk-catalyzed reaction to determine kinetic properties of these enzymes, in particular affinities for ATP. The assay allows variation of both nucleoside and phosphate donor substrates, thereby providing major advantages for the characterization of these enzymes. We confirm previously established kinetic parameters and identify differences in substrate selectivity between the two human Nrk isoforms. The proposed assay is inexpensive and may be applied for high-throughput screening.

  14. In situ enzymatic removal of orthophosphate by the nucleoside phosphorylase catalyzed phosphorolysis of nicotinamide riboside.

    Science.gov (United States)

    Shriver, J W; Sykes, B D

    1982-09-01

    An enzymatic orthophosphate removal system is described which can be effectively used to continuously remove orthophosphate from biochemical samples. The phosphorolysis of nicotinamide riboside is catalyzed by calf spleen nucleoside phosphorylase to give ribose-1-PO4 and nicotinamide along with a proton. At pH 8 the production of ribose-1-PO4 from orthophosphate is essentially quantitative. This reaction can be monitored optically or by 31P nuclear magnetic resonance (NMR). Equations are given for determining the time required to remove a given amount of phosphate from a typical NMR sample with a known amount of nucleoside phosphorylase. The effects of a competing orthophosphate-producing reaction are considered.

  15. A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention.

    Science.gov (United States)

    Chen, Andrew C; Martin, Andrew J; Choy, Bonita; Fernández-Peñas, Pablo; Dalziell, Robyn A; McKenzie, Catriona A; Scolyer, Richard A; Dhillon, Haryana M; Vardy, Janette L; Kricker, Anne; St George, Gayathri; Chinniah, Niranthari; Halliday, Gary M; Damian, Diona L

    2015-10-22

    Nonmelanoma skin cancers, such as basal-cell carcinoma and squamous-cell carcinoma, are common cancers that are caused principally by ultraviolet (UV) radiation. Nicotinamide (vitamin B3) has been shown to have protective effects against damage caused by UV radiation and to reduce the rate of new premalignant actinic keratoses. In this phase 3, double-blind, randomized, controlled trial, we randomly assigned, in a 1:1 ratio, 386 participants who had had at least two nonmelanoma skin cancers in the previous 5 years to receive 500 mg of nicotinamide twice daily or placebo for 12 months. Participants were evaluated by dermatologists at 3-month intervals for 18 months. The primary end point was the number of new nonmelanoma skin cancers (i.e., basal-cell carcinomas plus squamous-cell carcinomas) during the 12-month intervention period. Secondary end points included the number of new squamous-cell carcinomas and basal-cell carcinomas and the number of actinic keratoses during the 12-month intervention period, the number of nonmelanoma skin cancers in the 6-month postintervention period, and the safety of nicotinamide. At 12 months, the rate of new nonmelanoma skin cancers was lower by 23% (95% confidence interval [CI], 4 to 38) in the nicotinamide group than in the placebo group (P=0.02). Similar differences were found between the nicotinamide group and the placebo group with respect to new basal-cell carcinomas (20% [95% CI, -6 to 39] lower rate with nicotinamide, P=0.12) and new squamous-cell carcinomas (30% [95% CI, 0 to 51] lower rate, P=0.05). The number of actinic keratoses was 11% lower in the nicotinamide group than in the placebo group at 3 months (P=0.01), 14% lower at 6 months (Pnicotinamide was discontinued. Oral nicotinamide was safe and effective in reducing the rates of new nonmelanoma skin cancers and actinic keratoses in high-risk patients. (Funded by the National Health and Medical Research Council; ONTRAC Australian New Zealand Clinical Trials

  16. Predicting Visibility of Aircraft

    Science.gov (United States)

    Watson, Andrew; Ramirez, Cesar V.; Salud, Ellen

    2009-01-01

    Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration. PMID:19462007

  17. Measuring visibility using smartphones

    Science.gov (United States)

    Friesen, Jan; Bialon, Raphael; Claßen, Christoph; Graffi, Kalman

    2017-04-01

    Spatial information on fog density is an important parameter for ecohydrological studies in cloud forests. The Dhofar cloud forest in Southern Oman exhibits a close interaction between the fog, trees, and rainfall. During the three month monsoon season the trees capture substantial amounts of horizontal precipitation from fog which increases net precipitation below the tree canopy. As fog density measurements are scarce, a smartphone app was designed to measure visibility. Different smartphone units use a variety of different parts. It is therefore important to assess the developed visibility measurement across a suite of different smartphones. In this study we tested five smartphones/ tablets (Google/ LG Nexus 5X, Huawei P8 lite, Huawei Y3, HTC Nexus 9, and Samsung Galaxy S4 mini) against digital camera (Sony DLSR-A900) and visual visibility observations. Visibility was assessed from photos using image entropy, from the number of visible targets, and from WiFi signal strength using RSSI. Results show clear relationships between object distance and fog density, yet a considerable spread across the different smartphone/ tablet units is evident.

  18. Near-Infrared Light-Driven Photoelectrochemical Aptasensor Based on the Upconversion Nanoparticles and TiO2/CdTe Heterostructure for Detection of Cancer Cells.

    Science.gov (United States)

    Wang, Kewei; Zhang, Ruihua; Sun, Na; Li, Xinpan; Wang, Jine; Cao, Yi; Pei, Renjun

    2016-10-05

    A near-infrared-driven photoelectrochemical aptasensor was developed as a new method for the detection of the breast cancer cell MCF-7. The upconversion nanoparticles and TiO2/CdTe heterostructure were combined to prepare the film electrode, and the high-affinity aptamer AS1411 was conjugated to the electrode to recognize MCF-7 cells. In this fabrication, the upconversion nanoparticles transferred the near-infrared light to visible light, which could excite the semiconductor to enhance the current response. As a result, the aptasensor revealed good sensitivity and specificity with MCF-7 cell concentrations ranging from 1 × 103 to 1 × 105 cells/mL. The results presented a favorable determination of MCF-7 cells, which was achieved with the help of the upconversion nanoparticles and the photoelectrochemical interface.

  19. UVISS preliminary visibility analysis

    DEFF Research Database (Denmark)

    Betto, Maurizio

    1998-01-01

    The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part of the w......The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part...... of the work is also to setup the kernel of a software tool for the visibility analysis thatshould be easily expandable to consider more complex strucures for future activities.This analysis is part of the UVISS assessment study and it is meant to provide elementsfor the definition and the selection...

  20. Enhanced visible light photocatalytic hydrogen evolution over porphyrin hybridized graphitic carbon nitride.

    Science.gov (United States)

    Mei, Shunkang; Gao, Jianping; Zhang, Ye; Yang, Jiangbing; Wu, Yongli; Wang, Xiaoxue; Zhao, Ruiru; Zhai, Xiangang; Hao, Chaoyue; Li, Ruixia; Yan, Jing

    2017-11-15

    Tetra (4-carboxyphenyl) porphyrin (TCPP) was loaded on the surface of Pt/g-C3N4 via a simple adsorption process, and the microstructure and chemical structure of the composites were characterized by high resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-visible diffused reflectance spectroscopy and photoluminescence spectroscopy. Loading TCPP onto Pt/g-C3N4 enhanced the visible-light-driven photocatalytic evolution of H2 from water. The TCPP/Pt/g-C3N4 composite with a TCPP loading of 1wt% had the highest photoactivity, which was 2.1 times higher than that of Pt/g-C3N4. This improvement is attributed to enhanced visible light utilization by the TCPP/Pt/g-C3N4 resulting from the strong visible light response of TCPP. In addition, the formed organic heterostructure between TCPP and g-C3N4 with overlapping bad gaps accelerates the electron transfer and inhibits the recombination of the photogenerated electrons and holes on g-C3N4. Copyright © 2017. Published by Elsevier Inc.

  1. Between visibility and surveillance

    DEFF Research Database (Denmark)

    Uldam, Julie

    As activists move from alternative media platforms to commercial social media platforms they face increasing challenges in protecting their online security and privacy. While government surveillance of activists is well-documented in both scholarly research and the media, corporate surveillance...... of activists remains under-researched. This presentation explores visibility as a prerequisite and an obstacle to political participation. The dual capacity of visibility in social media enables both surveillance and counter-surveillance by making not only the surveilled actor, but also the surveilling actor......’ surveillance of anti-capitalist activists in social media....

  2. Making Invisible Forces Visible

    DEFF Research Database (Denmark)

    Ratner, Helene; Pors, Justine Grønbæk

    2013-01-01

    This paper investigates managerial tactics of visualisation when a need to know and manage employees' values and attitudes is expressed. Using the Danish public school as a case study, we explore how school managers use teachers' emotions to render visible presumably invisible information about...... their 'true' attitudes and values. The paper draws on theories of affect as well as actor-network theory to analyse three incidents where managers turn their interpretations of teachers' emotions into such information. These incidents suggest that the efforts to render employees' attitudes and values visible...

  3. (Gold core) at (ceria shell) nanostructures for plasmon-enhanced catalytic reactions under visible light

    KAUST Repository

    Wang, Jianfang

    2014-08-26

    Driving catalytic reactions with sunlight is an excellent example of sustainable chemistry. A prerequisite of solar-driven catalytic reactions is the development of photocatalysts with high solar-harvesting efficiencies and catalytic activities. Herein, we describe a general approach for uniformly coating ceria on monometallic and bimetallic nanocrystals through heterogeneous nucleation and growth. The method allows for control of the shape, size, and type of the metal core as well as the thickness of the ceria shell. The plasmon shifts of the Au@CeO2 nanostructures resulting from the switching between Ce(IV) and Ce(III) are observed. The selective oxidation of benzyl alcohol to benzaldehyde, one of the fundamental reactions for organic synthesis, performed under both broad-band and monochromatic light, demonstrates the visible-light-driven catalytic activity and reveals the synergistic effect on the enhanced catalysis of the Au@CeO2 nanostructures. © 2014 American Chemical Society.

  4. NadN and e (P4) are essential for utilization of NAD and nicotinamide mononucleotide but not nicotinamide riboside in Haemophilus influenzae.

    Science.gov (United States)

    Kemmer, G; Reilly, T J; Schmidt-Brauns, J; Zlotnik, G W; Green, B A; Fiske, M J; Herbert, M; Kraiss, A; Schlör, S; Smith, A; Reidl, J

    2001-07-01

    Haemophilus influenzae has an absolute requirement for NAD (factor V) because it lacks almost all the biosynthetic enzymes necessary for the de novo synthesis of that cofactor. Factor V can be provided as either nicotinamide adenosine dinucleotide (NAD), nicotinamide mononucleotide (NMN), or nicotinamide riboside (NR) in vitro, but little is known about the source or the mechanism of uptake of these substrates in vivo. As shown by us earlier, at least two gene products are involved in the uptake of NAD, the outer membrane lipoprotein e (P4), which has phosphatase activity and is encoded by hel, and a periplasmic NAD nucleotidase, encoded by nadN. It has also been observed that the latter gene product is essential for H. influenzae growth on media supplemented with NAD. In this report, we describe the functions and substrates of these two proteins as they act together in an NAD utilization pathway. Data are provided which indicate that NadN harbors not only NAD pyrophosphatase but also NMN 5'-nucleotidase activity. The e (P4) protein is also shown to have NMN 5'-nucleotidase activity, recognizing NMN as a substrate and releasing NR as its product. Insertion mutants of nadN or deletion and site-directed mutants of hel had attenuated growth and a reduced uptake phenotype when NMN served as substrate. A hel and nadN double mutant was only able to grow in the presence of NR, whereas no uptake of NMN was observed.

  5. Identification of Isn1 and Sdt1 as Glucose- and Vitamin-regulated Nicotinamide Mononucleotide and Nicotinic Acid Mononucleotide 5′-Nucleotidases Responsible for Production of Nicotinamide Riboside and Nicotinic Acid Riboside*

    Science.gov (United States)

    Bogan, Katrina L.; Evans, Charles; Belenky, Peter; Song, Peng; Burant, Charles F.; Kennedy, Robert; Brenner, Charles

    2009-01-01

    Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD+, which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast. Secreted nicotinamide riboside was detected with a biological assay, and intracellular levels of nicotinamide riboside, nicotinic acid riboside, and other NAD+ metabolites were determined by a liquid chromatography-mass spectrometry method. A biochemical genomic screen indicated that three yeast enzymes possess nicotinamide mononucleotide 5′-nucleotidase activity in vitro. Metabolic profiling of knock-out mutants established that Isn1 and Sdt1 are responsible for production of nicotinamide riboside and nicotinic acid riboside in cells. Isn1, initially classified as an IMP-specific 5′-nucleotidase, and Sdt1, initially classified as a pyrimidine 5′-nucleotidase, are additionally responsible for dephosphorylation of pyridine mononucleotides. Sdt1 overexpression is growth-inhibitory to cells in a manner that depends on its active site and correlates with reduced cellular NAD+. Expression of Isn1 protein is positively regulated by the availability of nicotinic acid and glucose. These results reveal unanticipated and highly regulated steps in NAD+ metabolism. PMID:19846558

  6. Identification of Isn1 and Sdt1 as glucose- and vitamin-regulated nicotinamide mononucleotide and nicotinic acid mononucleotide [corrected] 5'-nucleotidases responsible for production of nicotinamide riboside and nicotinic acid riboside.

    Science.gov (United States)

    Bogan, Katrina L; Evans, Charles; Belenky, Peter; Song, Peng; Burant, Charles F; Kennedy, Robert; Brenner, Charles

    2009-12-11

    Recently, we discovered that nicotinamide riboside and nicotinic acid riboside are biosynthetic precursors of NAD(+), which are utilized through two pathways consisting of distinct enzymes. In addition, we have shown that exogenously supplied nicotinamide riboside is imported into yeast cells by a dedicated transporter, and it extends replicative lifespan on high glucose medium. Here, we show that nicotinamide riboside and nicotinic acid riboside are authentic intracellular metabolites in yeast. Secreted nicotinamide riboside was detected with a biological assay, and intracellular levels of nicotinamide riboside, nicotinic acid riboside, and other NAD(+) metabolites were determined by a liquid chromatography-mass spectrometry method. A biochemical genomic screen indicated that three yeast enzymes possess nicotinamide mononucleotide 5'-nucleotidase activity in vitro. Metabolic profiling of knock-out mutants established that Isn1 and Sdt1 are responsible for production of nicotinamide riboside and nicotinic acid riboside in cells. Isn1, initially classified as an IMP-specific 5'-nucleotidase, and Sdt1, initially classified as a pyrimidine 5'-nucleotidase, are additionally responsible for dephosphorylation of pyridine mononucleotides. Sdt1 overexpression is growth-inhibitory to cells in a manner that depends on its active site and correlates with reduced cellular NAD(+). Expression of Isn1 protein is positively regulated by the availability of nicotinic acid and glucose. These results reveal unanticipated and highly regulated steps in NAD(+) metabolism.

  7. The visibility complex

    NARCIS (Netherlands)

    Pocchiola, M; Vegter, G

    We introduce the visibility complex (rr 2-dimensional regular cell complex) of a collection of n pairwise disjoint convex obstacles in the plane. It can be considered as a subdivision of the set of free rays (i.e., rays whose origins lie in free space, the complement of the obstacles). Its cells

  8. Visible Solid State Lasers

    NARCIS (Netherlands)

    Hikmet, R.A.M.

    2007-01-01

    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  9. Visible but Unseen?

    DEFF Research Database (Denmark)

    Torkilsheyggi, Arnvør Martinsdóttir á; Hertzum, Morten

    2015-01-01

    to support awareness in a setting where the users are (locally) mobile, specifically in regard to information that requires continuous monitoring. We do however also find that the whiteboard safeguarded the work with blood tests against some risks by making blood-test information socially visible....

  10. Evaluation of Visible Plumes.

    Science.gov (United States)

    Brennan, Thomas

    Developed for presentation at the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971, this outline discusses plumes with contaminants that are visible to the naked eye. Information covers: (1) history of air pollution control regulations, (2) need for methods of evaluating…

  11. Increasing NAD synthesis in muscle via nicotinamide phosphoribosyltransferase is not sufficient to promote oxidative metabolism.

    Science.gov (United States)

    Frederick, David W; Davis, James G; Dávila, Antonio; Agarwal, Beamon; Michan, Shaday; Puchowicz, Michelle A; Nakamaru-Ogiso, Eiko; Baur, Joseph A

    2015-01-16

    The NAD biosynthetic precursors nicotinamide mononucleotide and nicotinamide riboside are reported to confer resistance to metabolic defects induced by high fat feeding in part by promoting oxidative metabolism in skeletal muscle. Similar effects are obtained by germ line deletion of major NAD-consuming enzymes, suggesting that the bioavailability of NAD is limiting for maximal oxidative capacity. However, because of their systemic nature, the degree to which these interventions exert cell- or tissue-autonomous effects is unclear. Here, we report a tissue-specific approach to increase NAD biosynthesis only in muscle by overexpressing nicotinamide phosphoribosyltransferase, the rate-limiting enzyme in the salvage pathway that converts nicotinamide to NAD (mNAMPT mice). These mice display a ∼50% increase in skeletal muscle NAD levels, comparable with the effects of dietary NAD precursors, exercise regimens, or loss of poly(ADP-ribose) polymerases yet surprisingly do not exhibit changes in muscle mitochondrial biogenesis or mitochondrial function and are equally susceptible to the metabolic consequences of high fat feeding. We further report that chronic elevation of muscle NAD in vivo does not perturb the NAD/NADH redox ratio. These studies reveal for the first time the metabolic effects of tissue-specific increases in NAD synthesis and suggest that critical sites of action for supplemental NAD precursors reside outside of the heart and skeletal muscle. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Safety assessment of nicotinamide riboside, a form of vitamin B3.

    Science.gov (United States)

    Conze, D B; Crespo-Barreto, J; Kruger, C L

    2016-01-20

    Nicotinamide riboside (NR) is a naturally occurring form of vitamin B 3 present in trace amounts in some foods. Like niacin, it has been shown to be a precursor in the biosynthesis of nicotinamide adenine dinucleotide (NAD+). The safety of Niagen™, a synthetic form of NR, was determined using a bacterial reverse mutagenesis assay (Ames), an in vitro chromosome aberration assay, an in vivo micronucleus assay, and acute, 14-day and 90-day rat toxicology studies. NR was not genotoxic. There was no mortality at an oral dose of 5000 mg/kg. Based on the results of a 14-day study, a 90-day study was performed comparing NR at 300, 1000, and 3000 mg/kg/day to an equimolar dose of nicotinamide at 1260 mg/kg/day as a positive control. Results from the study show that NR had a similar toxicity profile to nicotinamide at the highest dose tested. Target organs of toxicity were liver, kidney, ovaries, and testes. The lowest observed adverse effect level for NR was 1000 mg/kg/day, and the no observed adverse effect level was 300 mg/kg/day. © The Author(s) 2016.

  13. Targeting Nicotinamide Phosphoribosyltransferase as a Potential Therapeutic Strategy to Restore Adult Neurogenesis.

    Science.gov (United States)

    Wang, Shu-Na; Xu, Tian-Ying; Li, Wen-Lin; Miao, Chao-Yu

    2016-06-01

    Adult neurogenesis is the process of generating new neurons throughout life in the olfactory bulb and hippocampus of most mammalian species, which is closely related to aging and disease. Nicotinamide phosphoribosyltransferase (NAMPT), also an adipokine known as visfatin, is the rate-limiting enzyme for mammalian nicotinamide adenine dinucleotide (NAD) salvage synthesis by generating nicotinamide mononucleotide (NMN) from nicotinamide. Recent findings from our laboratory and other laboratories have provided much evidence that NAMPT might serve as a therapeutic target to restore adult neurogenesis. NAMPT-mediated NAD biosynthesis in neural stem/progenitor cells is important for their proliferation, self-renewal, and formation of oligodendrocytes in vivo and in vitro. Therapeutic interventions by the administration of NMN, NAD, or recombinant NAMPT are effective for restoring adult neurogenesis in several neurological diseases. We summarize adult neurogenesis in aging, ischemic stroke, traumatic brain injury, and neurodegenerative disease and review the advances of targeting NAMPT in restoring neurogenesis. Specifically, we provide emphasis on the P7C3 family, a class of proneurogenic compounds that are potential NAMPT activators, which might shed light on future drug development in neurogenesis restoration. © 2016 John Wiley & Sons Ltd.

  14. More than skin deep? Potential nicotinamide treatment applications in chronic kidney transplant recipients.

    Science.gov (United States)

    Bostom, Andrew G; Merhi, Basma; Walker, Joanna; Robinson-Bostom, Leslie

    2016-12-24

    Non-melanoma cutaneous carcinomas, or skin cancers, predominantly squamous cell carcinomas (SCCs), are the most common malignancies occurring in kidney transplant recipients (KTRs). Squamous cell carcinoma risk is dramatically elevated in KTRs, occurring at rates of up 45-250 times those reported in general populations. New non-melanoma skin cancers in KTRs with a prior non-melanoma skin cancer also develop at 3-times the rate reported in non-KTRs with the same clinical history. The unique aggressiveness of SCCs in KTRs increases patient morbidity, due to the high rate of new lesions requiring treatment, frequently surgical excision. Oral nicotinamide shows promise in the chemoprevention of the especially aggressive non-melanoma skin cancers which occur in KTRs. This benefit might be conferred via its inhibition of sirtuin enzymatic pathways. Nicotinamide's concurrent hypophosphatemic effect may also partially ameliorate the disturbed calcium-phosphorus homeostasis in these patients-a putative risk factor for mortality, and graft failure. Conceivably, a phase 3 trial of nicotinamide for the prevention of non-melanoma skin cancers in KTRs, lasting at least 12-mo, could also incorporate imaging and laboratory measures which assess nicotinamide's impact on subclinical cardiovascular and chronic kidney disease risk, and progression.

  15. Expression patterns of nicotinamide phosphoribosyltransferase and nicotinic acid phosphoribosyltransferase in human malignant lymphomas

    DEFF Research Database (Denmark)

    Olesen, Uffe Høgh; Hastrup, Nina; Sehested, Maxwell

    2011-01-01

    The purpose of the study was to determine in human malignant lymphomas the expression patterns of nicotinamide phosphoribosyltransferase (NAMPT) and nicotinic acid phosphoribosyltransferase (NAPRT), the primary, rate-limiting enzymes in the synthesis of NAD+. NAMPT is a potential biomarker for se...

  16. Phosphorylation of 3-deazaguanosine by nicotinamide riboside kinase in Chinese hamster ovary cells.

    Science.gov (United States)

    Saunders, P P; Tan, M T; Spindler, C D; Robins, R K

    1989-12-01

    The growth inhibitory activity of 3-deazaguanosine toward a mutant line (TGR-3) of Chinese hamster ovary cells deficient in hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) was substantially reversed by the simultaneous addition of nicotinamide riboside. The activities of most other ribonucleoside analogues tested were unaffected. The formation of cellular 3-deazaGMP and 3-deazaGTP from the ribonucleoside analogue, as measured by high-pressure liquid chromatography, was inhibited by the presence of nicotinamide riboside. The inhibition was dependent on concentration of 3-deazaguanosine and could also be demonstrated by following the metabolism of 3-deazaguanosine, labeled with 14C in the ribose moiety, to [14C]3-deazaGTP. In the presence of 100 microM nicotinamide riboside formation of the labeled triphosphate derivative of 3-deazaguanosine was undetectable. A 3-deazaguanosine phosphorylating activity was separated from other cellular kinases by DEAE-cellulose chromatography. Contaminating purine nucleoside phosphorylase (EC 2.4.2.1) was subsequently removed by sucrose density gradient centrifugation. The resulting enzyme preparation demonstrated the greatest activities with nicotinamide riboside and 3-deazaguanosine and, in addition, could also phosphorylate tiazofurin and guanosine to lesser, but significant, degrees. These and other observations suggest that 3-deazaguanosine, and perhaps other agents such as tiazofurin, may, at least in part, be phosphorylated by a nicotinamide ribonucleoside kinase in these cells. If so, it is possible that the activity of this agent in other types of cells in vivo could be dependent upon the presence of this enzyme and that it could be influenced by cellular concentrations of the natural pyridine nucleoside.

  17. The evolving role of the NAD+/nicotinamide metabolome in skin homeostasis, cellular bioenergetics, and aging.

    Science.gov (United States)

    Oblong, John E

    2014-11-01

    Human skin is exposed to daily environmental insults, particularly solar radiation, that triggers a range of molecular responses. These perturbations to the normal homeostatic state can lead to cellular dysfunction and, ultimately, impacts tissue integrity and accelerates skin aging (photoaging). One of the responses is increased oxidative stress which has been shown to disrupt cellular bioenergetics. This can be detected by depletion of the nucleotide energy metabolites NAD+ and ATP as both an acute transient decrease and, over time, a more permanent chronic reduction due in part to cumulative damage of mitochondria. NAD+ and its primary precursor nicotinamide have been known for some time to impact skin homeostasis based on linkages to dietary requirements, treatment of various inflammatory conditions, photoaging, and prevention of cancer. Cellular NAD+ pools are known to be lower in aged skin and treatment with nicotinamide is hypothesized to restore these levels, thereby mitigating cellular bioenergetics dysfunction. In dermal fibroblasts, nicotinamide is able to protect against oxidative stress to glycolysis, oxidative phosphorylation as well as increase mitochondrial efficiency via sirtuin-dependent selective mitophagy. Recent research has found that NAD+ cellular pools are more dynamic than previously thought, oscillating in tandem with free nicotinamide, and serves as a regulatory point and feedback loop in cellular metabolism regulation, maintenance of mitochondrial efficiency, and circadian rhythmicity. Since UV-induced oxidative stress in skin can disrupt these processes, continued molecular understanding of the role of NAD+ and nicotinamide in skin biology is important to identify interventions that would help maintain its normal homeostatic functions and efficient cellular bioenergetics. Copyright © 2014. Published by Elsevier B.V.

  18. Scientific Opinion on the safety and efficacy of niacin (nicotinamide) as a feed additive for all animal species based on a dossier submitted by EUROPE-ASIA Import Export GmbH

    OpenAIRE

    EFSA Panel on Additives and Products or Substances used in Animal Feed

    2012-01-01

    The term ‘niacin’ is used as a generic description of nicotinic acid and nicotinamide with pyridine as the basic structure. Nicotinic acid and nicotinamide function mainly as precursors of the co-enzymes NAD and NADP. Thus, nicotinamide has physiologically critical roles in mitochondrial respiration and in the metabolism of carbohydrates, lipids, and amino acids. Oral administration routes of nicotinamide via feed or water for drinking are considered bioequivalent. Nicotinamide is sa...

  19. Making Heat Visible

    Science.gov (United States)

    Goodhew, Julie; Pahl, Sabine; Auburn, Tim; Goodhew, Steve

    2015-01-01

    Householders play a role in energy conservation through the decisions they make about purchases and installations such as insulation, and through their habitual behavior. The present U.K. study investigated the effect of thermal imaging technology on energy conservation, by measuring the behavioral effect after householders viewed images of heat escaping from or cold air entering their homes. In Study 1 (n = 43), householders who received a thermal image reduced their energy use at a 1-year follow-up, whereas householders who received a carbon footprint audit and a non-intervention control demonstrated no change. In Study 2 (n = 87), householders were nearly 5 times more likely to install draught proofing measures after seeing a thermal image. The effect was especially pronounced for actions that addressed an issue visible in the images. Findings indicate that using thermal imaging to make heat loss visible can promote energy conservation. PMID:26635418

  20. Social media visibility

    DEFF Research Database (Denmark)

    Uldam, Julie

    2017-01-01

    As activists move from alternative media platforms to commercial social media platforms, they face increasing challenges in protecting their online security and privacy. While government surveillance of activists is well-documented in scholarly research and the media, corporate surveillance...... for responding to the activities of individual activists in social media. It shows that while social media afford an unprecedented level of visibility for activists, it comes with the risk of being monitored by corporations. Theoretically, it draws on conceptions of visibility in social sciences and media...... studies as well as literature on activism and political participation in media studies. Empirically, it draws on files from BP on specific civil society individuals obtained through Subject Access Requests under the UK Data Protection Act 1998 as well as press responses from BP....

  1. On court interpreters' visibility

    DEFF Research Database (Denmark)

    Dubslaff, Friedel; Martinsen, Bodil

    of the service they receive. Ultimately, the findings will be used for training purposes. Future - and, for that matter, already practising - interpreters as well as the professional users of interpreters ought to take the reality of the interpreters' work in practice into account when assessing the quality...... in by the participants almost immediately after the interrogations and supplemented by interviews. The main objective of the project is to explore the interpreters' own perception of the quality of the service they render as well as the professional users´ and the other language users' perception of the quality...... of the interpreter as an invisible language switcher. However, a closer look at the data shows that, even in a less complex constellation like the one analysed here, there is clear evidence of the interpreter's visibility. We shall identify various forms of visibility based on the discourse data...

  2. Visibility graph motifs

    CERN Document Server

    Iacovacci, Jacopo

    2015-01-01

    Visibility algorithms transform time series into graphs and encode dynamical information in their topology, paving the way for graph-theoretical time series analysis as well as building a bridge between nonlinear dynamics and network science. In this work we introduce and study the concept of visibility graph motifs, smaller substructures that appear with characteristic frequencies. We develop a theory to compute in an exact way the motif profiles associated to general classes of deterministic and stochastic dynamics. We find that this simple property is indeed a highly informative and computationally efficient feature capable to distinguish among different dynamics and robust against noise contamination. We finally confirm that it can be used in practice to perform unsupervised learning, by extracting motif profiles from experimental heart-rate series and being able, accordingly, to disentangle meditative from other relaxation states. Applications of this general theory include the automatic classification a...

  3. Interferometric visibility and coherence

    Science.gov (United States)

    Biswas, Tanmoy; García Díaz, María; Winter, Andreas

    2017-07-01

    Recently, the basic concept of quantum coherence (or superposition) has gained a lot of renewed attention, after Baumgratz et al. (Phys. Rev. Lett. 113, 140401. (doi:10.1103/PhysRevLett.113.140401)), following Åberg (http://arxiv.org/abs/quant-ph/0612146), have proposed a resource theoretic approach to quantify it. This has resulted in a large number of papers and preprints exploring various coherence monotones, and debating possible forms for the resource theory. Here, we take the view that the operational foundation of coherence in a state, be it quantum or otherwise wave mechanical, lies in the observation of interference effects. Our approach here is to consider an idealized multi-path interferometer, with a suitable detector, in such a way that the visibility of the interference pattern provides a quantitative expression of the amount of coherence in a given probe state. We present a general framework of deriving coherence measures from visibility, and demonstrate it by analysing several concrete visibility parameters, recovering some known coherence measures and obtaining some new ones.

  4. Evacuation under limited visibility

    Science.gov (United States)

    Frank, Guillermo A.; Dorso, Claudio O.

    2015-06-01

    A multiplicity of situations can trigger off an evacuation of a room under panic conditions. For "normal" (with "normal" meaning absence of obstacles, perfect visibility, etc.) environmental conditions, the "faster is slower" effect dominates the dynamics of this process. It states that as the pedestrians desire to reach the exit increases, the clogging phenomena delays the time to get out of the room. But, environmental conditions are usually far from "normal." In this work, we consider that pedestrians have to find their way out under low visibility conditions. Some of them might switch to a herding-like behavior if they do not remember where the exit was. Others will just trust on their memory. Our investigation handles the herding and memory effects on the evacuation of a single exit room with no obstacles. We also include a section on how signaling devices affect the evacuation process. Unexpectedly, some low visibility situations may enhance the evacuation performance. This can be resumed as a second paradoxical result, since we demonstrated in an earlier investigation that "clever is not always better" G. A. Frank and C. O. Dorso, Physica A 390, 2135 (2011).

  5. Paradoxes of Visibility

    Directory of Open Access Journals (Sweden)

    Tarnay László

    2017-12-01

    Full Text Available The paper investigates two possible critical arguments following the pictorial turn. The first is formulated within ocularcentrism, the dominance of sight, and starts with the right to visibility as a general principle that governs today’s digital culture but gets twisted in special cases like the Auschwitz photos of the Shoa, the Abu Ghraib prison videos, or recently the website called Yolocaust. The second is conceived outside the visual culture and is meant to vindicate the other senses vis-à-vis the eyes. However, the argument is truncated here only to highlight the boomerang effect of the other senses: haptic vision. It is the case of visual perception when (a there is a lack of things to see and (b indeterminate synaesthesia: when vision intensifies the other senses in the embodied viewer. The two arguments converge upon a dialectic of the visible and the imaginable, which is formulated here as two paradoxes that the discussed examples transcend. By enforcing visibility at all costs where there is hardly anything recognizable to see, they lead to two diverging results. On the one hand, the meaning of “image” is extended toward the unimaginable, the traumatic experience, on the other hand, it is extended toward the invisible, the encounter with the radical Other.

  6. Highly efficient photocatalytic hydrogen evolution of graphene/YInO3 nanocomposites under visible light irradiation.

    Science.gov (United States)

    Ding, Jianjun; Yan, Wenhao; Xie, Wei; Sun, Song; Bao, Jun; Gao, Chen

    2014-02-21

    Visible-light-driven hydrogen evolution with high efficiency is important in the current photocatalysis research. Here we report for the first time the design and synthesis of a new graphene-semiconductor nanocomposite consisting of YInO3 nanoparticles and two-dimensional graphene sheets as efficient photocatalysts for hydrogen evolution under visible light irradiation. The graphene/YInO3 nanocomposites were synthesized using a facile solvothermal method in which the formation of graphene and the deposition of YInO3 nanoparticles on the graphene sheets can be achieved simultaneously. The addition of graphene as a cocatalyst can narrow the band gap of YInO3 to visible photon energy and prolong the separation and lifetime of electron-hole pairs by the chemical bonding between YInO3 and graphene. The photocatalytic reaction with this nanocomposite reaches a high H2 evolution rate of 400.4 μmol h(-1) g(-1) when the content of graphene is 0.5 wt%, over 127 and 3.7 times higher than that of pure YInO3 and Pt/YInO3, respectively. This work can provide an effective approach to the fabrication of graphene-based photocatalysts with high performance in the field of energy conversion.

  7. Nicotinamide riboside and nicotinic acid riboside salvage in fungi and mammals. Quantitative basis for Urh1 and purine nucleoside phosphorylase function in NAD+ metabolism.

    Science.gov (United States)

    Belenky, Peter; Christensen, Kathryn C; Gazzaniga, Francesca; Pletnev, Alexandre A; Brenner, Charles

    2009-01-02

    NAD+ is a co-enzyme for hydride transfer enzymes and an essential substrate of ADP-ribose transfer enzymes and sirtuins, the type III protein lysine deacetylases related to yeast Sir2. Supplementation of yeast cells with nicotinamide riboside extends replicative lifespan and increases Sir2-dependent gene silencing by virtue of increasing net NAD+ synthesis. Nicotinamide riboside elevates NAD+ levels via the nicotinamide riboside kinase pathway and by a pathway initiated by splitting the nucleoside into a nicotinamide base followed by nicotinamide salvage. Genetic evidence has established that uridine hydrolase, purine nucleoside phosphorylase, and methylthioadenosine phosphorylase are required for Nrk-independent utilization of nicotinamide riboside in yeast. Here we show that mammalian purine nucleoside phosphorylase but not methylthioadenosine phosphorylase is responsible for mammalian nicotinamide riboside kinase-independent nicotinamide riboside utilization. We demonstrate that so-called uridine hydrolase is 100-fold more active as a nicotinamide riboside hydrolase than as a uridine hydrolase and that uridine hydrolase and mammalian purine nucleoside phosphorylase cleave nicotinic acid riboside, whereas the yeast phosphorylase has little activity on nicotinic acid riboside. Finally, we show that yeast nicotinic acid riboside utilization largely depends on uridine hydrolase and nicotinamide riboside kinase and that nicotinic acid riboside bioavailability is increased by ester modification.

  8. Facile One-Step Route for the Development of in Situ Cocatalyst-Modified Ti(3+) Self-Doped TiO2 for Improved Visible-Light Photocatalytic Activity.

    Science.gov (United States)

    Kumar, Raju; Govindarajan, Sivakumar; Siri Kiran Janardhana, Reddy Kunda; Rao, Tata Narasinga; Joshi, Shrikant Vishwanath; Anandan, Srinivasan

    2016-10-05

    Development of visible-light-driven photocatalysts by employing a relatively simple, efficient, and cost-effective one-step process is essential for commercial applications. Herein, we report for the first time the synthesis of in situ Cu-ion modified Ti(3+) self-doped rutile TiO2 by such a facile one-step solution precursor plasma spray (SPPS) process using a water-soluble titanium precursor. In the SPPS process, Ti(3+) self-doping on Ti(4+) of rutile TiO2 is found to take place because of electron transfer from the created oxygen vacancies to Ti(4+)-ions. In situ Cu modification of the above Ti(3+) self-doped rutile TiO2 by additionally introducing a Cu solution into plasma plume is also demonstrated. While the Ti(3+) self-doping induces broad absorption in the visible-light region, the addition of Cu ion leads to even broader absorption in the visible region owing to resulting synergistic properties. The above materials were evaluated for various self-cleaning photocatalytic applications under visible-light illumination. Cu-ion modified Ti(3+) self-doped rutile TiO2 is noted to exhibit a remarkably enhanced visible-light activity in comparison with Ti(3+) self-doped rutile TiO2, with the latter itself outperforming commercial TiO2 photocatalysts, thereby suggesting the suitability of the material for indoor applications. The broad visible-light absorption by Ti(3+) self-doping, the holes with strong oxidation power generated in the valence band, and electrons in Ti(3+) isolated states that are effectively separated into the high reductive sites of Cu ions upon visible-light irradiation, accounts for improved photocatalytic activity. Moreover, the synthesis process (SPPS) provides a valuable alternative to orthodox multistep processes for the preparation of such visible-light-driven photocatalysts.

  9. NICOTINAMIDE IN COMPLEX TREATMENT OF LARGE-PLAQUE PARAPSORIASIS AND EARLY STAGES OF MALIGNANT T-CELL SKIN LYMPHOMAS

    Directory of Open Access Journals (Sweden)

    I. V. Khamaganova

    2014-01-01

    Full Text Available Aim: To assess clinical efficacy of nicotinamide in 2 the treatment of patients with early stages of malignant T-cell skin lymphomas and large-plaque parapsoriasis. Materials and methods: 12 patients with erythematous stage of mycosis fungoides and 14 patients with large-plaque parapsoriasis were treated by nicotinamide 15 mg twice daily during 2 weeks. Treatment cycles were repeated 4–5 times per year; topical therapy was also administrated. Results: Nicotinamide demonstrated high therapeutic effect and good tolerability in patients with early stage of mycosis fungoides and large-plaque parapsoriasis. Stable remission was achieved in 1  woman with malignant T-cell lymphoma and 12  patients with large-plaque parapsoriasis; significant clinical improvement was shown in 8 and 12 patients, respectively. Conclusion: Thus, nicotinamide is recommended for comprehensive treatment of large-plaque parapsoriasis and early stages of mycosis fungoides.

  10. Nicotinamide inhibits Propionibacterium acnes-induced IL-8 production in keratinocytes through the NF-kappaB and MAPK pathways.

    Science.gov (United States)

    Grange, Philippe A; Raingeaud, Joël; Calvez, Vincent; Dupin, Nicolas

    2009-11-01

    Propionibacterium acnes (P. acnes) has been implicated in the inflammatory phase of acne vulgaris. It has been shown to activate interleukin-8 (IL-8) secretion by interacting with Toll-like receptor 2 (TLR-2) on the surface of keratinocytes. Nicotinamide has been shown to be an effective treatment for skin inflammation in various conditions, including acne vulgaris. To investigate the molecular mechanisms underlying the anti-inflammatory properties of nicotinamide in keratinocytes stimulated by P. acnes. HaCaT cells and primary keratinocyte cell lines were stimulated by P. acnes in the presence of nicotinamide. IL-8 production was monitored by ELISA on the cell culture supernatant and by qRT-PCR on total RNA extract. A luciferase reporter system assay was used to assess nicotinamide activity with the IL-8 promoter in transfected keratinocytes. We used western blotting to analyze the effect of nicotinamide on activation of the NF-kappaB and MAPK pathways. Nicotinamide significantly decreased IL-8 production in a dose-dependent manner, decreasing both mRNA and protein levels for this chemokine in immortalized HaCaT cells and primary keratinocytes. P. acnes-induced IL-8 promoter activation seemed to be downregulated by nicotinamide, which inhibited IkappaB degradation and the phosphorylation of ERK and JNK MAP kinases. Our results indicate that nicotinamide inhibits IL-8 production through the NF-kappaB and MAPK pathways in an in vitro keratinocytes/P. acnes model of inflammation. Keratinocytes involved in the innate immune response may be a suitable target for treatment during the early phase of inflammation.

  11. Nicotinamide induces mitochondrial-mediated apoptosis through oxidative stress in human cervical cancer HeLa cells.

    Science.gov (United States)

    Feng, Yi; Wang, Yonghua; Jiang, Chengrui; Fang, Zishui; Zhang, Zhiqiang; Lin, Xiaoying; Sun, Liwei; Jiang, Weiying

    2017-07-15

    Nicotinamide participates in energy metabolism and influences cellular redox status and modulates multiple pathways related with both cellular survival and death. Recent studies have shown that it induced proliferation inhibition and apoptosis in many cancer cells. However, little is known about the effects of nicotinamide on human cervical cancer cells. We aimed to evaluate the effects of the indicated concentrations nicotinamide on cell proliferation, apoptosis and redox-related parameters in HeLa cells and investigated the apoptotic mechanism. After the treatment of the indicated concentrations nicotinamide, HeLa cell proliferation was evaluated by the CCK-8 assay and the production of ROS (reactive oxygen species) was measured using 2',7'-Dichlorofluorescin diacetate. The apoptotic effect was confirmed by observing the cellular and nuclear morphologies with fluorescence microscope and apoptotic rate of HeLa cell apoptosis was measured by flow cytometry using Annexin-V method. Moreover, we examined the mitochondrial membrane potential by JC-1 method and measured the expression of apoptosis related genes using qRT-PCR and immunoblotting. Nicotinamide restrained the HeLa cell proliferation and significantly increased the accumulation of ROS and depletion of GSH at relatively high concentrations. Furthermore, nicotinamide promoted HeLa cell apoptosis via the intrinsic mitochondrial apoptotic pathway. Our study revealed that nicotinamide induced the apoptosis through oxidative stress and intrinsic mitochondrial apoptotic pathways in HeLa cell. The results emerge that nicotinamide may be an inexpensive, safe and promising therapeutic agent or a neoadjuvant chemotherapy for cervical cancer patients, as well useful to find new drugs for cervical cancer therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Highly Visible Light Responsive, Narrow Band gap TiO2 Nanoparticles Modified by Elemental Red Phosphorus for Photocatalysis and Photoelectrochemical Applications

    Science.gov (United States)

    Ansari, Sajid Ali; Cho, Moo Hwan

    2016-01-01

    This paper reports that the introduction of elemental red phosphorus (RP) into TiO2 can shift the light absorption ability from the UV to the visible region, and confirmed that the optimal RP loading and milling time can effectively improve the visible light driven-photocatalytic activity of TiO2. The resulting RP-TiO2 nanohybrids were characterized systematically by a range of techniques and the photocatalytic ability of the RP-TiO2 photocatalysts was assessed further by the photodegradation of a model Rhodamine B pollutant under visible light irradiation. The results suggest that the RP-TiO2 has superior photodegradation ability for model contaminant decomposition compared to other well-known photocatalysts, such as TiO2 and other reference materials. Furthermore, as a photoelectrode, electrochemical impedance spectroscopy, differential pulse voltammetry, and linear scan voltammetry were also performed in the dark and under visible light irradiation. These photoelectrochemical performances of RP-TiO2 under visible light irradiation revealed more efficient photoexcited electron-hole separation and rapid charge transfer than under the dark condition, and thus improved photocatalytic activity. These findings show that the use of earth abundant and inexpensive red phosphorus instead of expensive plasmonic metals for inducing visible light responsive characteristics in TiO2 is an effective strategy for the efficient energy conversion of visible light. PMID:27146098

  13. The visible ear simulator

    DEFF Research Database (Denmark)

    Sorensen, Mads Solvsten; Mosegaard, Jesper; Mikkelsen, Peter Trier

    2009-01-01

    material.Virtual training often requires the purchase of a program, a customized computer, and expensive peripherals dedicated exclusively to this purpose. MATERIALS AND METHODS: The Visible Ear freeware library of digital images from a fresh-frozen human temporal bone was segmented, and real-time volume......, 2D, or optional anaglyph stereoscopic 3D was achieved on a standard Core 2 Duo personal computer with a GeForce 8,800 GTX graphics card, and surgical interaction was provided through a relatively inexpensive (approximately $2,500) Phantom Omni haptic 3D pointing device. CONCLUSION: This prototype...

  14. WWW visibility in marketing

    OpenAIRE

    Ollila, T.

    2013-01-01

    Social media is a vital channel for marketers nowadays. Customers are more empowered today than ever before and the Internet is accelerating the trend toward greater customer empowerment. In few years Web 2.0 has become a highly important media and it has changed the Web into platform where individuals can communicate, assemble and organize data. Web 2.0 also offers a variety of different “tools” for companies to be used in marketing. Because companies and products are visible and discussed i...

  15. Hydrothermal synthesis of hierarchical rose-like Bi{sub 2}WO{sub 6} microspheres with high photocatalytic activities under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    He Jinyun, E-mail: hejinyun@glite.edu.cn [Sate Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004 (China); Wang Weimin, E-mail: wangwm@hotmail.com [Sate Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Long Fei; Zou Zhengguang [Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004 (China); Fu Zhengyi [Sate Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Xu Zhe [Hubei Province Supervision and Testing Institute For Building Materials Product Quality, Wuhan 430071 (China)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Rose-like Bi{sub 2}WO{sub 6} microspheres were synthesized through a hydrothermal route. Black-Right-Pointing-Pointer Thiourea and acetic acid were used as complexing agents. Black-Right-Pointing-Pointer The microspheres were constructed by many nanoflakes with nanocrystals on them. Black-Right-Pointing-Pointer The structure was formed through a hierarchical assembly process. Black-Right-Pointing-Pointer The photocatalyst showed excellent visible-light-driven photocatalytic performance. - Abstract: Hierarchical rose-like Bi{sub 2}WO{sub 6} photocatalyst was successfully synthesized through a simple hydrothermal route using thiourea and acetic acid as complexing agents. The as-synthesized product was determined as pure orthorhombic Bi{sub 2}WO{sub 6} based on the results of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. The photocatalyst had an average diameter of 2-3 {mu}m and it was constructed by many nanoflakes. The surfaces of these nanoflakes were coarse and had many nanocrystals on them. The hierarchical rose-like structure was formed through a typical hierarchical assembly process with the synergistic action of acetic acid and thiourea. The photocatalyst showed excellent visible-light-driven photocatalytic performance, it could decompose rhodamine B(RhB) within 50 min. This excellent performance resulted from its special microstructure and the relatively large surface area.

  16. Prevention of non-melanoma skin cancers with nicotinamide in transplant recipients: a case-control study.

    Science.gov (United States)

    Drago, Francesco; Ciccarese, Giulia; Cogorno, Ludovica; Calvi, Camillo; Marsano, Luigina A; Parodi, Aurora

    2017-08-01

    Nicotinamide is the precursor of nicotinamide adenine dinucleotide (NAD+), an essential cofactor for adenosine triphosphate (ATP) production. It has recently been reported to be effective in reducing the rates of new non-melanoma skin cancers (NMSCs) and actinic keratosis (AKs). We studied the efficacy of oral nicotinamide as treatment for AKs in transplant recipients. We recruited 38 transplant (eight liver and 30 kidney) patients with single or multiple AKs. Nineteen patients were randomly assigned to Group 1 and took nicotinamide 500 mg/daily (cases); the other 19 patients were randomly assigned to Group 2 without nicotinamide (controls). At baseline, AKs were identified, measured, and photographed for follow-up. Five patients underwent an AK biopsy for histopathology. Statistical analyses were performed using the Student t test. At baseline, no statistically significant differences were observed regarding AK size between the two groups. After six months, among the cases, AKs had significantly decreased in size in 18/19 patients (88%). Among these 18 patients, seven patients (42%) had shown complete clinical regression and no patient developed new AKs. Conversely, among the controls, 91% showed an increase in AK size and/or developed new AKs. Seven pre-existing AKs progressed to squamous-cell carcinoma. Nicotinamide appears to be effective in preventing and treating AKs, although the mechanisms are still unclear. Further studies with a larger sample of organ transplant recipients and a longer follow-up period are needed to further support our conclusions.

  17. Different effects of histone deacetylase inhibitors nicotinamide and trichostatin A (TSA) in C17.2 neural stem cells.

    Science.gov (United States)

    Wang, Haifeng; Cheng, Hua; Wang, Kai; Wen, Tieqiao

    2012-11-01

    Histone deacetylase inhibitors are involved in proliferation, apoptosis, cell cycle, mRNA transcription, and protein expression in various cells. However, the molecular mechanism underlying such functions is still not fully clear. In this study, we used C17.2 neural stem cell (NSC) line as a model to evaluate the effects of nicotinamide and trichostatin A (TSA) on cell characteristics. Results show that nicotinamide and TSA greatly inhibit cell growth, lead to cell morphology changes, and effectively induce cell apoptosis in a dose-dependent manner. Western blot analyses confirmed that nicotinamide significantly decreases the expression of bcl-2 and p38. Further insight into the molecular mechanisms shows the suppression of phosphorylation in eukaryotic initiation factor 4E-binding protein 1 (4EBP1) by nicotinamide, whereas, an increased expression of bcl-2 and p38 and phosphorylation of 4EBP1 by TSA. However, both nicotinamide and TSA significantly increase the expression of cytochrome c (cyt c). These results strongly suggest that bcl-2, p38, cyt c, and p-4EBP1 could suppress proliferation and induce apoptosis of C17.2 NSCs mediated by histone deacetylase inhibitors, nicotinamide and TSA, involving different molecular mechanisms.

  18. Nicotinamide riboside is uniquely and orally bioavailable in mice and humans.

    Science.gov (United States)

    Trammell, Samuel A J; Schmidt, Mark S; Weidemann, Benjamin J; Redpath, Philip; Jaksch, Frank; Dellinger, Ryan W; Li, Zhonggang; Abel, E Dale; Migaud, Marie E; Brenner, Charles

    2016-10-10

    Nicotinamide riboside (NR) is in wide use as an NAD + precursor vitamin. Here we determine the time and dose-dependent effects of NR on blood NAD + metabolism in humans. We report that human blood NAD + can rise as much as 2.7-fold with a single oral dose of NR in a pilot study of one individual, and that oral NR elevates mouse hepatic NAD + with distinct and superior pharmacokinetics to those of nicotinic acid and nicotinamide. We further show that single doses of 100, 300 and 1,000 mg of NR produce dose-dependent increases in the blood NAD + metabolome in the first clinical trial of NR pharmacokinetics in humans. We also report that nicotinic acid adenine dinucleotide (NAAD), which was not thought to be en route for the conversion of NR to NAD + , is formed from NR and discover that the rise in NAAD is a highly sensitive biomarker of effective NAD + repletion.

  19. Melanoma and nonmelanoma skin cancer chemoprevention: A role for nicotinamide?

    Science.gov (United States)

    Minocha, Rashi; Damian, Diona L; Halliday, Gary M

    2018-01-01

    Ultraviolet radiation (UVR) causes DNA damage in melanocytes by producing photolesions such as cyclobutane pyrimidine dimers and 8-oxo-7-hydrodeoxyguanosine. The production of reactive oxygen species by UVR also induces inflammatory cytokines that, together with the inherent immunosuppressive properties of UVR, propagate carcinogenesis. Nicotinamide (Vitamin B 3 ) enhances DNA repair, modulates the inflammatory environment produced by UVR, and reduces UV-induced immunosuppression. As nicotinamide reduces the incidence of actinic keratoses and nonmelanoma skin cancers in high-risk individuals and enhances repair of DNA damage in melanocytes, it is a promising agent for the chemoprevention of melanoma in high-risk populations. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Cancer stem cell overexpression of nicotinamide N-methyltransferase enhances cellular radiation resistance

    DEFF Research Database (Denmark)

    D’Andrea, Filippo P.; Safwat, Akmal; Kassem, Moustapha

    2011-01-01

    validated with q-RT-PCR using TaqMan probes. ResultsThe CE8 clone was more radiation resistant than the BB3 clone. From a pool of 15 validated genes with altered expression in the CE8 clone, we found the enzyme nicotinamide N-methyltransferase (NNMT) more than 5-fold upregulated. In-depth pathway analysis...... found the genes involved in cancer, proliferation, DNA repair and cell death. ConclusionsThe higher radiation resistance in clone CE8 is likely due to NNMT overexpression. The higher levels of NNMT could affect the cellular damage resistance through depletion of the accessible amounts of nicotinamide......, which is a known inhibitor of cellular DNA repair mechanisms....

  1. Discoveries of nicotinamide riboside as a nutrient and conserved NRK genes establish a Preiss-Handler independent route to NAD+ in fungi and humans.

    Science.gov (United States)

    Bieganowski, Pawel; Brenner, Charles

    2004-05-14

    NAD+ is essential for life in all organisms, both as a coenzyme for oxidoreductases and as a source of ADPribosyl groups used in various reactions, including those that retard aging in experimental systems. Nicotinic acid and nicotinamide were defined as the vitamin precursors of NAD+ in Elvehjem's classic discoveries of the 1930s. The accepted view of eukaryotic NAD+ biosynthesis, that all anabolism flows through nicotinic acid mononucleotide, was challenged experimentally and revealed that nicotinamide riboside is an unanticipated NAD+ precursor in yeast. Nicotinamide riboside kinases from yeast and humans essential for this pathway were identified and found to be highly specific for phosphorylation of nicotinamide riboside and the cancer drug tiazofurin. Nicotinamide riboside was discovered as a nutrient in milk, suggesting that nicotinamide riboside is a useful compound for elevation of NAD+ levels in humans.

  2. Sustained delivery of nicotinamide limits cortical injury and improves functional recovery following traumatic brain injury

    OpenAIRE

    Goffus, Andrea M.; Anderson, Gail D; Hoane, Michael R.

    2010-01-01

    Previously, we have demonstrated that nicotinamide (NAM), a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI). However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral contr...

  3. Sustained Delivery of Nicotinamide Limits Cortical Injury and Improves Functional Recovery Following Traumatic Brain Injury

    OpenAIRE

    Goffus, Andrea M.; Anderson, Gail D; Hoane, Michael R.

    2010-01-01

    Previously, we have demonstrated that nicotinamide (NAM), a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI). However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral contr...

  4. beta-1,2,3-Triazolyl-nucleosides as nicotinamide riboside mimics.

    Science.gov (United States)

    Amigues, E J; Armstrong, E; Dvorakova, M; Migaud, M E; Huang, M

    2009-03-01

    The synthesis of a series of pyridine- and piperidine-substituted 1,2,3-triazolides linked to a riboside moiety is described. The presence of a triazolide substituent on the pyridine moiety permitted the facile reduction of the latter under mild hydrogenation conditions. These analogues were modelled as to define their similarity to nicotinamide riboside and quantify their ability to bind NAD-dependent protein deacetylases.

  5. Metabolomics Analysis of Metabolic Effects of Nicotinamide Phosphoribosyltransferase (NAMPT) Inhibition on Human Cancer Cells

    Science.gov (United States)

    Tolstikov, Vladimir; Nikolayev, Alexander; Dong, Sucai; Zhao, Genshi; Kuo, Ming-Shang

    2014-01-01

    Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in cellular bioenergetics. It is responsible for converting nicotinamide to nicotinamide adenine dinucleotide, an essential molecule in cellular metabolism. NAMPT has been extensively studied over the past decade due to its role as a key regulator of nicotinamide adenine dinucleotide–consuming enzymes. NAMPT is also known as a potential target for therapeutic intervention due to its involvement in disease. In the current study, we used a global mass spectrometry–based metabolomic approach to investigate the effects of FK866, a small molecule inhibitor of NAMPT currently in clinical trials, on metabolic perturbations in human cancer cells. We treated A2780 (ovarian cancer) and HCT-116 (colorectal cancer) cell lines with FK866 in the presence and absence of nicotinic acid. Significant changes were observed in the amino acids metabolism and the purine and pyrimidine metabolism. We also observed metabolic alterations in glycolysis, the citric acid cycle (TCA), and the pentose phosphate pathway. To expand the range of the detected polar metabolites and improve data confidence, we applied a global metabolomics profiling platform by using both non-targeted and targeted hydrophilic (HILIC)-LC-MS and GC-MS analysis. We used Ingenuity Knowledge Base to facilitate the projection of metabolomics data onto metabolic pathways. Several metabolic pathways showed differential responses to FK866 based on several matches to the list of annotated metabolites. This study suggests that global metabolomics can be a useful tool in pharmacological studies of the mechanism of action of drugs at a cellular level. PMID:25486521

  6. INTERACTIVE EFFECTS OF SALINITY STRESS AND NICOTINAMIDE ON PHYSIOLOGICAL AND BIOCHEMICAL PARAMETERS ON FABA BEAN PLANT

    Directory of Open Access Journals (Sweden)

    Magdi T. Abdelhamid

    2013-09-01

    Full Text Available A possible survival strategy of plants under saline conditions is to use some compounds that could alleviate salt stress effect. One of these compounds is nicotinamide. The effect of exogenously application of nicotinamide with different concentrations (0, 200 and 400 mg/l on Vicia faba L. plant against different NaCl treatments (0, 50 and 100 mM NaCl was investigated at the wire house of the National Research Centre, Cairo, Egypt. Salinity stress reduced significantly plant height, dry weight of shoot, photosynthetic pigments, polysaccharides, total carbohydrates, total-N contents of shoot, seed yield, total carbohydrates & total crude protein of the yielded seeds compared with those of the control plants. In contrast, salinity induced marked increases in sucrose, total soluble sugars, total free amino acids, proline, lipid peroxidation product (MDA and some oxidative enzymes (polyphenol oxidase and peroxidase enzymes. Also, salinity stress increased Na+ contents with the decreases of other macro and micro elements contents (P, K+, Mg+, Ca2+, Fe2+, Mn2+, Zn2+ and Cu2+ of shoots and the yielded seeds of faba bean. Foliar spraying of nicotinamide alleviated the adverse effects of salinity stress through increased plant height, dry weight of shoot, photosynthetic pigments, polysaccharides, total carbohydrates, total-N contents of shoot and seed yield as well as, sucrose, total soluble sugars, total free amino acids and proline, compared with those of the corresponding salinity levels, while decreased lipid peroxidation product as MDA and the oxidative enzymes (polyphenol oxidase and peroxidase enzymes. Nicotinamide inhibited the uptake of Na+ and accelerated the accumulation of P, K+ , Mg+, Ca2+, Fe2+, Mn2+, Zn2+ and Cu2+ contents in the shoots of salt stressed plants and enhanced total carbohydrate and total crude protein percentage and solutes concentrations in seeds of salinity treated plants. 

  7. Metabolomics analysis of metabolic effects of nicotinamide phosphoribosyltransferase (NAMPT inhibition on human cancer cells.

    Directory of Open Access Journals (Sweden)

    Vladimir Tolstikov

    Full Text Available Nicotinamide phosphoribosyltransferase (NAMPT plays an important role in cellular bioenergetics. It is responsible for converting nicotinamide to nicotinamide adenine dinucleotide, an essential molecule in cellular metabolism. NAMPT has been extensively studied over the past decade due to its role as a key regulator of nicotinamide adenine dinucleotide-consuming enzymes. NAMPT is also known as a potential target for therapeutic intervention due to its involvement in disease. In the current study, we used a global mass spectrometry-based metabolomic approach to investigate the effects of FK866, a small molecule inhibitor of NAMPT currently in clinical trials, on metabolic perturbations in human cancer cells. We treated A2780 (ovarian cancer and HCT-116 (colorectal cancer cell lines with FK866 in the presence and absence of nicotinic acid. Significant changes were observed in the amino acids metabolism and the purine and pyrimidine metabolism. We also observed metabolic alterations in glycolysis, the citric acid cycle (TCA, and the pentose phosphate pathway. To expand the range of the detected polar metabolites and improve data confidence, we applied a global metabolomics profiling platform by using both non-targeted and targeted hydrophilic (HILIC-LC-MS and GC-MS analysis. We used Ingenuity Knowledge Base to facilitate the projection of metabolomics data onto metabolic pathways. Several metabolic pathways showed differential responses to FK866 based on several matches to the list of annotated metabolites. This study suggests that global metabolomics can be a useful tool in pharmacological studies of the mechanism of action of drugs at a cellular level.

  8. Nicotinamide riboside, a form of vitamin B3, protects against excitotoxicity-induced axonal degeneration.

    Science.gov (United States)

    Vaur, Pauline; Brugg, Bernard; Mericskay, Mathias; Li, Zhenlin; Schmidt, Mark S; Vivien, Denis; Orset, Cyrille; Jacotot, Etienne; Brenner, Charles; Duplus, Eric

    2017-12-01

    NAD + depletion is a common phenomenon in neurodegenerative pathologies. Excitotoxicity occurs in multiple neurologic disorders and NAD + was shown to prevent neuronal degeneration in this process through mechanisms that remained to be determined. The activity of nicotinamide riboside (NR) in neuroprotective models and the recent description of extracellular conversion of NAD + to NR prompted us to probe the effects of NAD + and NR in protection against excitotoxicity. Here, we show that intracortical administration of NR but not NAD + reduces brain damage induced by NMDA injection. Using cortical neurons, we found that provision of extracellular NR delays NMDA-induced axonal degeneration (AxD) much more strongly than extracellular NAD + Moreover, the stronger effect of NR compared to NAD + depends of axonal stress since in AxD induced by pharmacological inhibition of nicotinamide salvage, both NAD + and NR prevent neuronal death and AxD in a manner that depends on internalization of NR. Taken together, our findings demonstrate that NR is a better neuroprotective agent than NAD + in excitotoxicity-induced AxD and that axonal protection involves defending intracellular NAD + homeostasis.-Vaur, P., Brugg, B., Mericskay, M., Li, Z., Schmidt, M. S., Vivien, D., Orset, C., Jacotot, E., Brenner, C., Duplus, E. Nicotinamide riboside, a form of vitamin B 3 , protects against excitotoxicity-induced axonal degeneration. © FASEB.

  9. Docetaxel-nicotinamide complex-loaded nanostructured lipid carriers for transdermal delivery.

    Science.gov (United States)

    Fan, Xiucong; Chen, Jinjin; Shen, Qi

    2013-12-31

    Docetaxel (DTX) proved one of the most effective active pharmaceutical ingredients (APIs) for the treatment of cancers. However, in respect of its low solubility and high lipophilic property, nicotinamide (NCT) was chosen as the co-former to form the docetaxel-nicotinamide complex to handle the drawbacks. As was analyzed by Fourier Transform Infrared spectrometer, thermal analysis and saturated solubility, the complex proved stable. Then, docetaxel-nicotinamide complex nanostructured lipid carriers (DN-NLCs) were prepared by emulsion-evaporation at low temperature method. The average drug entrapment efficiency, particle size and drug loading of docetaxel-NLCs (D-NLCs) and DN-NLCs were 81.41-79.48%, 61.45-59.48nm and 1.60-1.63%, respectively. The physicochemical characteristics of nanoparticles were valued by transmission electron microscope and Powder X Ray Diffraction. The in vitro drug-release profile of nanoparticle formulations fitted the Weibull dynamic equation. The skin permeability test was performed by Vertical Franz-type diffusion cells. It demonstrated that DN-NLCs transported drugs more easily than D-NLCs. Confocal Laser Scanning Microscopy observation showed DN-NLCs permeated more effectively than D-NLCs. In vivo study demonstrated that DN-NLCs maintained most in the skin. These results suggest that the DN-NLCs can be a useful method to increase skin permeation of docetaxel. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  10. Nicotinamide Riboside and Nicotinic Acid Riboside Salvage in Fungi and Mammals: QUANTITATIVE BASIS FOR Urh1 AND PURINE NUCLEOSIDE PHOSPHORYLASE FUNCTION IN NAD+METABOLISM*S⃞

    OpenAIRE

    Belenky, Peter; Christensen, Kathryn C.; Gazzaniga, Francesca; Pletnev, Alexandre A.; Brenner, Charles

    2009-01-01

    NAD+ is a co-enzyme for hydride transfer enzymes and an essential substrate of ADP-ribose transfer enzymes and sirtuins, the type III protein lysine deacetylases related to yeast Sir2. Supplementation of yeast cells with nicotinamide riboside extends replicative lifespan and increases Sir2-dependent gene silencing by virtue of increasing net NAD+ synthesis. Nicotinamide riboside elevates NAD+ levels via the nicotinamide riboside kinase pathway and by a pathway initiate...

  11. In situ preparation of cubic Cu2O-RGO nanocomposites for enhanced visible-light degradation of methyl orange.

    Science.gov (United States)

    Zhang, Wei; Li, Xiaolin; Yang, Zhi; Tang, Xuehui; Ma, Yujie; Li, Ming; Hu, Nantao; Wei, Hao; Zhang, Yafei

    2016-07-01

    There has been a growing interest in gathering together photocatalysis of semiconductors, like cuprous oxide (Cu2O), and the excellent electron transmittability of graphene to produce a graphene-based semiconductor for photocatalytic degradation. In this paper, a mild one-pot in situ synthesis of cubic cuprous oxide-reduced graphene oxide (Cu2O-RGO) nanocomposites has been proposed for the removal of methyl orange. In contrast to pure cubic Cu2O particles under similar preparation conditions, the cubic Cu2O-RGO nanocomposites demonstrate enhanced visible-light-driven photocatalytic activity for methyl orange dye with a 100% degradation rate in 100 min. The enhanced photocatalytic performance is mainly attributed to the increased charge transportation, effective separation of photoelectrons from vacancies, and the improved contact area.

  12. Big brains, meat, tuberculosis and the nicotinamide switches: co-evolutionary relationships with modern repercussions on longevity and disease?

    Science.gov (United States)

    Williams, Adrian C; Dunbar, Robin I M

    2014-07-01

    Meat eating has been an important trigger for human evolution however the responsible component in meat has not been clearly identified. Here we propose that the limiting factors for expanding brains and increasing longevity were the micronutrient nicotinamide (vitamin B3) and the metabolically related essential amino-acid, tryptophan. Meat offers significant sourcing challenges and lack causes a deficiency of nicotinamide and tryptophan and consequently the energy carrier nicotinamide adenine dinucleotide (NAD) that gets consumed in regulatory circuits important for survival, resulting in premature ageing, poor cognition and brain atrophy. If a trophic supply of dietary nicotinamide/tryptophan is so essential for building brains, constraining their size and connectivity, we hypothesise that back-up mechanisms to ensure the supply evolved. One strategy may be increasing the reliance on gut symbionts to break down celluloses that produces NADH and only nicotinamide indirectly, and may cause diarrhoea. We suggest that a direct supplier was the chronic mycobacterial infection tuberculosis (TB) that is a surprise candidate but it co-evolved early, does not inevitably cause disease (90-95% of those infected are healthy), and secretes (and is inhibited by) nicotinamide. We hypothesise that TB evolved first as a symbiont that enabled humans to cope with short-lived shortages of meat and only later behaved as a pathogen when the supply deteriorated chronically, for those in poverty. (TB immunology and epidemiology is riddled with paradoxes for a conventional pathogen). We test this in pilot data showing that sharp declines in TB (and diarrhoea) - `environmental enteropathy' strongly correlate with increasing meat consumption and therefore nicotinamide exposure, unlike later onset cancers and Parkinson's disease that increased in incidence, perhaps - as we propose a hypothetical hypervitaminosis B3 (to include obesity and the metabolic syndrome) - as the trade-off for

  13. Preparation of novel Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts and their activities under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    He, Guo-Hua; Liang, Can-Jian; Ou, Yu-Da; Liu, Dan-Ni; Fang, Yue-Ping [Institute of Biomaterial, College of Science, South China Agricultural University, Guangzhou 510642 (China); Xu, Yue-Hua, E-mail: xuyuehua@scau.edu.cn [Institute of Biomaterial, College of Science, South China Agricultural University, Guangzhou 510642 (China)

    2013-06-01

    Highlights: ► Visible-light-driven Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were synthesized. ► Results showed that RhB can be decomposed using a 4 W LED lamp as visible light. ► The coupling of Sb{sub 2}O{sub 3} and WO{sub 3} enhanced the photocatalytic activity of WO{sub 3}. - Abstract: Novel visible-light-driven Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were prepared by a hydrothermal synthesis followed by heat treatment, and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area, Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectra (PL). The photocatalytic activities of Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were evaluated by the rhodamine B degradation using a LED lamp as visible light irradiation. Compared with pure WO{sub 3} and Sb{sub 2}O{sub 3}, the significantly enhanced photocatalytic activities of the Sb{sub 2}O{sub 3}/WO{sub 3} composite particles are attributed to the decrease of the recombination rate of photoinduced electron–hole pairs due to the coupling of Sb{sub 2}O{sub 3} and WO{sub 3} within the composite nanoparticles. Studies of Sb{sub 2}O{sub 3}/WO{sub 3} composites indicate that one approach to design composite materials with enhanced photocatalytic performance is through coupling Sb{sub 2}O{sub 3} with WO{sub 3}, which the lowest energy states for electrons and holes are in different semiconductors.

  14. ATST visible broadband imager

    Science.gov (United States)

    McBride, William R.; Wöger, Friedrich; Hegwer, Steve L.; Ferayorni, Andrew; Gregory, B. Scott

    2012-09-01

    The Advanced Technology Solar Telescope (ATST) is a 4 meter class telescope for observation of the solar atmosphere currently in the construction phase. The Visible Broadband Imager (VBI) is a diffraction limited imaging instrument planned to be the first-light instrument in the ATST instrumentation suite. The VBI is composed of two branches, the "VBI blue" and the "VBI red", and uses state-of-the-art narrow bandwidth interference filters and two custom designed high speed filter wheels to take bursts of images that will be re-constructed using a Graphics Processing Unit (GPU) optimized near-real-time speckle image reconstruction engine. At first light, the VBI instrument will produce diffraction-limited movies of solar activity at eight discrete wavelengths with a field of view of 2 arc minutes square. In this contribution, the VBI design team will discuss the capabilities of the VBI and describe the design of the instrument, highlighting the unique challenges faced in the development of this unique instrument.

  15. New function for Escherichia coli xanthosine phophorylase (xapA): genetic and biochemical evidences on its participation in NAD+ salvage from nicotinamide

    Science.gov (United States)

    2014-01-01

    Background In an effort to reconstitute the NAD+ synthetic pathway in Escherichia coli (E. coli), we produced a set of gene knockout mutants with deficiencies in previously well-defined NAD+de novo and salvage pathways. Unexpectedly, the mutant deficient in NAD+de novo and salvage pathway I could grow in M9/nicotinamide medium, which was contradictory to the proposed classic NAD+ metabolism of E. coli. Such E. coli mutagenesis assay suggested the presence of an undefined machinery to feed nicotinamide into the NAD+ biosynthesis. We wanted to verify whether xanthosine phophorylase (xapA) contributed to a new NAD+ salvage pathway from nicotinamide. Results Additional knockout of xapA further slowed down the bacterial growth in M9/nicotinamide medium, whereas the complementation of xapA restored the growth phenotype. To further validate the new function of xapA, we cloned and expressed E. coli xapA as a recombinant soluble protein. Biochemical assay confirmed that xapA was capable of using nicotinamide as a substrate for nicotinamide riboside formation. Conclusions Both the genetic and biochemical evidences indicated that xapA could convert nicotinamide to nicotinamide riboside in E. coli, albeit with relatively weak activity, indicating that xapA may contribute to a second NAD+ salvage pathway from nicotinamide. We speculate that this xapA-mediated NAD+ salvage pathway might be significant in some bacteria lacking NAD+de novo and NAD+ salvage pathway I or II, to not only use nicotinamide riboside, but also nicotinamide as precursors to synthesize NAD+. However, this speculation needs to be experimentally tested. PMID:24506841

  16. New function for Escherichia coli xanthosine phophorylase (xapA): genetic and biochemical evidences on its participation in NAD(+) salvage from nicotinamide.

    Science.gov (United States)

    Dong, Wei-Ren; Sun, Cen-Cen; Zhu, Guan; Hu, Shi-Hua; Xiang, Li-Xin; Shao, Jian-Zhong

    2014-02-08

    In an effort to reconstitute the NAD(+) synthetic pathway in Escherichia coli (E. coli), we produced a set of gene knockout mutants with deficiencies in previously well-defined NAD(+)de novo and salvage pathways. Unexpectedly, the mutant deficient in NAD(+) de novo and salvage pathway I could grow in M9/nicotinamide medium, which was contradictory to the proposed classic NAD(+) metabolism of E. coli. Such E. coli mutagenesis assay suggested the presence of an undefined machinery to feed nicotinamide into the NAD(+) biosynthesis. We wanted to verify whether xanthosine phophorylase (xapA) contributed to a new NAD(+) salvage pathway from nicotinamide. Additional knockout of xapA further slowed down the bacterial growth in M9/nicotinamide medium, whereas the complementation of xapA restored the growth phenotype. To further validate the new function of xapA, we cloned and expressed E. coli xapA as a recombinant soluble protein. Biochemical assay confirmed that xapA was capable of using nicotinamide as a substrate for nicotinamide riboside formation. Both the genetic and biochemical evidences indicated that xapA could convert nicotinamide to nicotinamide riboside in E. coli, albeit with relatively weak activity, indicating that xapA may contribute to a second NAD(+) salvage pathway from nicotinamide. We speculate that this xapA-mediated NAD(+) salvage pathway might be significant in some bacteria lacking NAD(+) de novo and NAD(+) salvage pathway I or II, to not only use nicotinamide riboside, but also nicotinamide as precursors to synthesize NAD(+). However, this speculation needs to be experimentally tested.

  17. Microemulsion synthesis, characterization of highly visible light responsive rare earth-doped Bi2O3.

    Science.gov (United States)

    Wu, Shuxing; Fang, Jianzhang; Xu, Xiaoxin; Liu, Zhang; Zhu, Ximiao; Xu, Weicheng

    2012-01-01

    In this paper, Bi(2)O(3) and rare earth (La, Ce)-doped Bi(2)O(3) visible-light-driven photocatalysts were prepared in a Triton X-100/n-hexanol/cyclohexane/water reverse microemulsion. The resulting materials were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area, photoluminescence spectra (PLS) and UV-Vis diffuse reflectance spectroscopy. The XRD patterns of the as-prepared catalysts calcined at 500 °C exhibited only the characteristic peaks of monoclinic α-Bi(2)O(3). PLS analysis implied that the separation efficiency for electron-hole has been enhanced when Bi(2)O(3) was doped with rare earth. UV-Vis diffuse reflectance spectroscopy measurements presented an extension of light absorption into the visible region. The photocatalytic activity of the samples was evaluated by degradation of methyl orange (MO) and 2,4-dichlorophenol (2,4-DCP). The results displayed that the photocatalytic activity of rare earth-doped Bi(2)O(3) was higher than that of dopant-free Bi(2)O(3). The optimal dopant amount of La or Ce was 1.0 mol%. And the mechanisms of influence on the photocatalytic activity of the catalysts were discussed. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  18. Light-driven molecular machine at ITIES

    DEFF Research Database (Denmark)

    Kornyshev, A.A.; Kuimova, M.; Kuznetsov, A.M.

    2007-01-01

    We suggest a principle of operation of a new molecular device that transforms the energy of light into repetitive mechanical motions. Such a device can also serve as a model system for the study of the effect of electric field on intramolecular electron transfer. We discuss the design of suitable...... molecular systems and the methods that may monitor the 'performance' of such a machine.......We suggest a principle of operation of a new molecular device that transforms the energy of light into repetitive mechanical motions. Such a device can also serve as a model system for the study of the effect of electric field on intramolecular electron transfer. We discuss the design of suitable...

  19. Light driven assembly of active colloids

    Science.gov (United States)

    Aubret, Antoine; Mena, Youssef; Ramananarivo, Sophie; Sacanna, Stefano; Palacci, Jeremie

    Self-propelled particles (SPP) are a key tool since they are of relative simplicity as compared to biological micro-entities and provide a higher level of control. They can convert an energy source into motion and work, and exhibit surprising non-equilibrium behavior. In our work, we focus on the manipulation of colloids using light. We exploit osmotic and phoretic effects to act on single and ensemble of colloids. The key mechanism relies on the photocatalytic decomposition of hydrogen peroxide using hematite, which triggers the motion of colloids around it when illuminated. We use hematite particles and particles with photocatalytic inclusions (i.e. SPP). We first show that the interactions between hematite and colloidal tracers can be tuned by adjusting the chemical environment. Furthermore, we report a phototaxic behavior (migration in light gradient) of the particles. From this, we explore the effect of spatio-temporal modulation of the light to control the motion of colloids at the single particle level, and to generate self-assembled colloidal structures through time and space. The so-formed structures are maintained by phoretic and hydrodynamic forces resulting from the motion of each particles. Ultimately, a dynamic light modulation may be a route for the creation of act

  20. Purification and characterization of the enzymes involved in nicotinamide adenine dinucleotide degradation by Penicillium brevicompactum NRC 829.

    Science.gov (United States)

    Ali, Thanaa Hamed; El-Ghonemy, Dina Helmy

    2016-06-01

    The present study was conducted to investigate a new pathway for the degradation of nicotinamide adenine dinucleotide (NAD) by Penicillium brevicompactum NRC 829 extracts. Enzymes involved in the hydrolysis of NAD, i.e. alkaline phosphatase, aminohydrolase and glycohydrolase were determined. Alkaline phosphatase was found to catalyse the sequential hydrolysis of two phosphate moieties of NAD molecule to nicotinamide riboside plus adenosine. Adenosine was then deaminated by aminohydrolase to inosine and ammonia. While glycohydrolase catalyzed the hydrolysis of the nicotinamide-ribosidic bond of NAD+ to produce nicotinamide and ADP-ribose in equimolar amounts, enzyme purification through a 3-step purification procedure revealed the existence of two peaks of alkaline phosphatases, and one peak contained deaminase and glycohydrolase activities. NAD deaminase was purified to homogeneity as estimated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis with an apparent molecular mass of 91 kDa. Characterization and determination of some of NAD aminohydrolase kinetic properties were conducted due to its biological role in the regulation of cellular NAD level. The results also revealed that NAD did not exert its feedback control on nicotinamide amidase produced by P. brevicompactum.

  1. Inhibitory effect of nicotinamide on in vitro and in vivo production of tumor necrosis factor-alpha.

    Science.gov (United States)

    Fukuzawa, M; Satoh, J; Muto, G; Muto, Y; Nishimura, S; Miyaguchi, S; Qiang, X L; Toyota, T

    1997-10-01

    Nicotinamide, a pellagra-preventive factor, has multiple functions such as inhibition of poly-ADP-ribose synthetase, inhibition of inducible nitric oxide synthase, free radical scavenging and suppression of major histocompatibility complex class II expression and ICAM-1 expression on endothelial cells. In addition to these, we have found an inhibitory effect of nicotinamide on production of tumor necrosis factor-alpha (TNF-alpha) in vitro and in vivo. Lipopolysaccharide (LPS)-induced in vitro TNF-alpha production by human peripheral blood mononuclear cells, measured by enzyme-linked immunosorbent assay (ELISA), was significantly inhibited with more than 1 x 10(-3) mol/l of nicotinamide, while interleukin-1-beta was not inhibited and interleukin-6 was slightly inhibited even with 10(-2) mol/l. Oral administration of nicotinamide with more than 62.5 mg/kg also significantly inhibited LPS-induced serum TNF-alpha production measured by ELISA and bioassay in Balb/c mice. Thus, nicotinamide has an inhibitory effect on TNF-alpha production that may be beneficial to TNF-alpha-mediated diseases.

  2. DYNAMICALLY MAINTAINING THE VISIBILITY GRAPH

    NARCIS (Netherlands)

    VEGTER, G

    1991-01-01

    An algorithm is presented to maintain the visibility graph of a set of N line segments in the plane in O(log2 N + K log N) time, where K is the total number of arcs of the visibility graph that are destroyed or created upon insertion or deletion of a line segment. The line segments should be

  3. Revisiting visibility in the plane

    DEFF Research Database (Denmark)

    Wilkinson, Bryan Thomas

    Abstract We consider two closely related problems: computing the region visible from a point amid simple polygonal obstacles and computing the lower envelope of a set of disjoint segments. Visibility problems such as these were proposed and promptly solved in the late'80s and early'90s before...

  4. Non-Euclidean visibility problems

    Indian Academy of Sciences (India)

    We prove a visibility criterion and study orchard problem and the cardinality of visible points in large circles. Author Affiliations. Fernando Chamizo1. Departamento de Matemáticas, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain. Dates. Manuscript received: 14 November 2005. Proceedings ...

  5. Visible Jovian Aurora

    Science.gov (United States)

    1997-01-01

    Jupiter's aurora on the night side of the planet is seen here at five different wavelengths. Jupiter's bright crescent, which is about half illuminated, is out of view to the right. North is at the top. The images are centered at 57 degrees north and 184 degrees West and were taken on April 2, 1997 at a range of 1.7 million kilometers (1.05 million miles) by the Solid State Imaging (SSI) camera system aboard NASA's Galileo spacecraft.Although Jupiter's aurora had been imaged from Earth in the ultraviolet and infrared, these are the first images at visible wavelengths, where most of the emission takes place. CLR stands for clear (no filter) and shows the integrated brightness at all wavelengths. The other panels show the violet, green, red, and 889 nanometer-wavelength filtered images. The brightness of the aurora is roughly independent of wavelength, at least at the spectral resolution obtainable with these filters.As on Earth, the aurora is caused by electrically charged particles striking the upper atmosphere, causing the molecules of the atmosphere to glow. The brightness in the different filters contains information about the energy of the impinging particles and the composition of the upper atmosphere. If atomic hydrogen were the only emitter, the light would be much stronger in the red filter, which is not consistent with the observed distribution.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at: http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at: http:/ /www.jpl.nasa.gov/galileo/sepo.

  6. Alteration in substrate specificity of horse liver alcohol dehydrogenase by an acyclic nicotinamide analog of NAD(+).

    Science.gov (United States)

    Malver, Olaf; Sebastian, Mina J; Oppenheimer, Norman J

    2014-11-01

    A new, acyclic NAD-analog, acycloNAD(+) has been synthesized where the nicotinamide ribosyl moiety has been replaced by the nicotinamide (2-hydroxyethoxy)methyl moiety. The chemical properties of this analog are comparable to those of β-NAD(+) with a redox potential of -324mV and a 341nm λmax for the reduced form. Both yeast alcohol dehydrogenase (YADH) and horse liver alcohol dehydrogenase (HLADH) catalyze the reduction of acycloNAD(+) by primary alcohols. With HLADH 1-butanol has the highest Vmax at 49% that of β-NAD(+). The primary deuterium kinetic isotope effect is greater than 3 indicating a significant contribution to the rate limiting step from cleavage of the carbon-hydrogen bond. The stereochemistry of the hydride transfer in the oxidation of stereospecifically deuterium labeled n-butanol is identical to that for the reaction with β-NAD(+). In contrast to the activity toward primary alcohols there is no detectable reduction of acycloNAD(+) by secondary alcohols with HLADH although these alcohols serve as competitive inhibitors. The net effect is that acycloNAD(+) has converted horse liver ADH from a broad spectrum alcohol dehydrogenase, capable of utilizing either primary or secondary alcohols, into an exclusively primary alcohol dehydrogenase. This is the first example of an NAD analog that alters the substrate specificity of a dehydrogenase and, like site-directed mutagenesis of proteins, establishes that modifications of the coenzyme distance from the active site can be used to alter enzyme function and substrate specificity. These and other results, including the activity with α-NADH, clearly demonstrate the promiscuity of the binding interactions between dehydrogenases and the riboside phosphate of the nicotinamide moiety, thus greatly expanding the possibilities for the design of analogs and inhibitors of specific dehydrogenases. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Nicotinamide N-methyltransferase knockdown protects against diet-induced obesity

    Science.gov (United States)

    Kraus, Daniel; Yang, Qin; Kong, Dong; Banks, Alexander S.; Zhang, Lin; Rodgers, Joseph T.; Pirinen, Eija; Pulinilkunnil, Thomas C.; Gong, Fengying; Wang, Ya-chin; Cen, Yana; Sauve, Anthony A.; Asara, John M.; Peroni, Odile D.; Monia, Brett P.; Bhanot, Sanjay; Alhonen, Leena; Puigserver, Pere; Kahn, Barbara B.

    2014-01-01

    In obesity and type 2 diabetes, Glut4 glucose transporter expression is decreased selectively in adipocytes1. Adipose-specific knockout or overexpression of Glut4 alters systemic insulin sensitivity2. Here we show, using DNA array analyses, that nicotinamide N-methyltransferase (Nnmt) is the most strongly reciprocally regulated gene when comparing gene expression in white adipose tissue (WAT) from adipose-specific Glut4-knockout or adipose-specific Glut4-overexpressing mice with their respective controls. NNMT methylates nicotinamide (vitamin B3) using S-adenosylmethionine (SAM) as a methyl donor3,4. Nicotinamide is a precursor of NAD+, an important cofactor linking cellular redox states with energy metabolism5. SAM provides propylamine for polyamine biosynthesis and donates a methyl group for histone methylation6. Polyamine flux including synthesis, catabolism and excretion, is controlled by the rate-limiting enzymes ornithine decarboxylase (ODC) and spermidine–spermine N1-acetyltransferase (SSAT; encoded by Sat1) and by polyamine oxidase (PAO), and has a major role in energy metabolism7,8. We report that NNMT expression is increased in WAT and liver of obese and diabetic mice. Nnmt knockdown in WAT and liver protects against diet-induced obesity by augmenting cellular energy expenditure. NNMT inhibition increases adipose SAM and NAD+ levels and upregulates ODC and SSAT activity as well as expression, owing to the effects of NNMT on histone H3 lysine 4 methylation in adipose tissue. Direct evidence for increased polyamine flux resulting from NNMT inhibition includes elevated urinary excretion and adipocyte secretion of diacetylspermine, a product of polyamine metabolism. NNMT inhibition in adipocytes increases oxygen consumption in an ODC-, SSAT- and PAO-dependent manner. Thus, NNMT is a novel regulator of histone methylation, polyamine flux and NAD+-dependent SIRT1 signalling, and is a unique and attractive target for treating obesity and type 2 diabetes. PMID

  8. Nicotinamide Riboside Preserves Cardiac Function in a Mouse Model of Dilated Cardiomyopathy.

    Science.gov (United States)

    Diguet, Nicolas; Trammell, Samuel A J; Tannous, Cynthia; Deloux, Robin; Piquereau, Jérôme; Mougenot, Nathalie; Gouge, Anne; Gressette, Mélanie; Manoury, Boris; Blanc, Jocelyne; Breton, Marie; Decaux, Jean-François; Lavery, Gareth; Baczkó, István; Zoll, Joffrey; Garnier, Anne; Li, Zhenlin; Brenner, Charles; Mericskay, Mathias

    2017-12-07

    Background -Myocardial metabolic impairment is a major feature in chronic heart failure (HF). As the major coenzyme in fuel oxidation and oxidative phosphorylation and a substrate for enzymes signaling energy stress and oxidative stress response, NAD + is emerging as a metabolic target in a number of diseases including HF. Little is known on mechanisms regulating homeostasis of NAD + in the failing heart. Methods -To explore possible alterations of NAD + homeostasis in the failing heart, we quantified expression of NAD + biosynthetic enzymes in human failing heart and in the heart of a mouse model of dilated cardiomyopathy (DCM) triggered by SRF transcription factor depletion in the heart (SRF HKO ) or of cardiac hypertrophy triggered by transverse aorta constriction (TAC). We studied the impact of NAD + precursor supplementation on cardiac function in both mouse models. Results -We observed a 30% loss in levels of NAD + in the murine failing heart of both DCM and TAC mice that was accompanied by a decrease in expression of the NAMPT enzyme that recycles the nicotinamide (NAM) precursor whereas the nicotinamide riboside kinase 2 (NMRK2) that phosphorylates the nicotinamide riboside (NR) precursor is increased, to a higher level in the DCM (40 fold) than in TAC (4 fold). This shift was also observed in human failing heart biopsies compared to non-failing controls. We show that the Nmrk2 gene is an AMPK and PPARalpha responsive gene that is activated by energy stress and NAD + depletion in isolated rat cardiomyocytes. NR efficiently rescues NAD + synthesis in response to FK866-mediated inhibition of NAMPT and stimulates glycolysis in cardiomyocytes. Accordingly, we show that NR supplementation in food attenuates the development of HF in mice, more robustly in DCM, and partially after TAC, by stabilizing myocardial NAD + levels in the failing heart. NR treatment also robustly increases the myocardial levels of three metabolites, nicotinic acid adenine dinucleotide

  9. SAR and characterization of non-substrate isoindoline urea inhibitors of nicotinamide phosphoribosyltransferase (NAMPT).

    Science.gov (United States)

    Curtin, Michael L; Heyman, H Robin; Clark, Richard F; Sorensen, Bryan K; Doherty, George A; Hansen, T Matthew; Frey, Robin R; Sarris, Kathy A; Aguirre, Ana L; Shrestha, Anurupa; Tu, Noah; Woller, Kevin; Pliushchev, Marina A; Sweis, Ramzi F; Cheng, Min; Wilsbacher, Julie L; Kovar, Peter J; Guo, Jun; Cheng, Dong; Longenecker, Kenton L; Raich, Diana; Korepanova, Alla V; Soni, Nirupama B; Algire, Mikkel A; Richardson, Paul L; Marin, Violeta L; Badagnani, Ilaria; Vasudevan, Anil; Buchanan, F Greg; Maag, David; Chiang, Gary G; Tse, Chris; Michaelides, Michael R

    2017-08-01

    Herein we disclose SAR studies that led to a series of isoindoline ureas which we recently reported were first-in-class, non-substrate nicotinamide phosphoribosyltransferase (NAMPT) inhibitors. Modification of the isoindoline and/or the terminal functionality of screening hit 5 provided inhibitors such as 52 and 58 with nanomolar antiproliferative activity and preclinical pharmacokinetics properties which enabled potent antitumor activity when dosed orally in mouse xenograft models. X-ray crystal structures of two inhibitors bound in the NAMPT active-site are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. SAR and characterization of non-substrate isoindoline urea inhibitors of nicotinamide phosphoribosyltransferase (NAMPT)

    Energy Technology Data Exchange (ETDEWEB)

    Curtin, Michael L.; Heyman, H. Robin; Clark, Richard F.; Sorensen, Bryan K.; Doherty, George A.; Hansen, T. Matthew; Frey, Robin R.; Sarris, Kathy A.; Aguirre, Ana L.; Shrestha, Anurupa; Tu, Noah; Woller, Kevin; Pliushchev, Marina A.; Sweis, Ramzi F.; Cheng, Min; Wilsbacher, Julie L.; Kovar, Peter J.; Guo, Jun; Cheng, Dong; Longenecker, Kenton L.; Raich, Diana; Korepanova, Alla V.; Soni, Nirupama B.; Algire, Mikkel A.; Richardson, Paul L.; Marin, Violeta L.; Badagnani, Ilaria; Vasudevan, Anil; Buchanan, F.Greg; Maag, David; Chiang, Gary G.; Tse, Chris; Michaelides, Michael R. (AbbVie)

    2017-08-01

    Herein we disclose SAR studies that led to a series of isoindoline ureas which we recently reported were first-in-class, non-substrate nicotinamide phosphoribosyltransferase (NAMPT) inhibitors. Modification of the isoindoline and/or the terminal functionality of screening hit 5 provided inhibitors such as 52 and 58 with nanomolar antiproliferative activity and preclinical pharmacokinetics properties which enabled potent antitumor activity when dosed orally in mouse xenograft models. X-ray crystal structures of two inhibitors bound in the NAMPT active-site are discussed.

  11. Metabolism of Nicotinamide Adenine Dinucleotide in Human and Bovine Strains of Mycobacterium tuberculosis

    Science.gov (United States)

    Kasǎrov, Luka B.; Moat, Albert G.

    1972-01-01

    A marked difference was found to exist between the nicotinamide adenine dinucleotide (NAD) glycohydrolase activity of human strains of Mycobacterium tuberculosis as compared with bovine strains. Human strains had from 6- to 20-fold higher NAD glycohydrolase activity than bovine strains. This finding explains the accumulation of free nicotinic acid in the culture medium by human strains and not by bovine strains. The biosynthetic intermediates nicotinic acid mononucleotide and deamido-NAD were not degraded by either human or bovine strains of M. tuberculosis; hence these nucleotides do not represent a source of the nicotinic acid accumulated by the human strains. PMID:4336690

  12. Topical nicotinamide modulates cellular energy metabolism and provides broad-spectrum protection against ultraviolet radiation-induced immunosuppression in humans.

    Science.gov (United States)

    Sivapirabu, G; Yiasemides, E; Halliday, G M; Park, J; Damian, D L

    2009-12-01

    Ultraviolet (UV) radiation can profoundly suppress the cutaneous immune system, thus enhancing carcinogenesis. Agents that prevent UV-induced immunosuppression may thus reduce skin cancer. Nicotinamide (vitamin B3) prevents UV-induced immunosuppression and carcinogenesis in mice, and solar-simulated (ss) UV-induced immunosuppression in humans. Its effectiveness against different UV wavebands and mechanism of action is as yet unknown. To determine the effects and mechanisms of topical nicotinamide on UV-induced suppression of delayed type hypersensitivity (DTH) responses in humans. Healthy Mantoux-positive volunteers in four randomised, double-blinded studies were irradiated with solar-simulated (ss)UV (UVB + UVA) or narrowband UVB (300 nm) or UVA (385 nm). Topical nicotinamide (0.2% or 5%) or its vehicle were applied immediately after each irradiation. Mantoux testing was performed at irradiated sites and adjacent unirradiated control sites 48 h after the first irradiation and measured 72 h later. Immunosuppression was calculated as the difference in Mantoux-induced erythema and induration at test sites compared to control sites. Human keratinocyte cell cultures, with and without ssUV and nicotinamide, were used for quantitative real-time reverse transcriptase-polymerase chain reaction assessment of TP53 and enzymes that regulate oxidative phosphorylation. Nicotinamide cooperated with ssUV to increase enzymes involved in cellular energy metabolism and p53, and significantly protected against immunosuppression caused by UVB, longwave UVA and single and repeated ssUV exposures. Longwave UVA, which is poorly filtered by most sunscreens, was highly immune suppressive even at doses equivalent to 20 min of sun exposure. Nicotinamide, which protected against both UVB and UVA, is a promising agent for skin cancer prevention.

  13. Nicotinamide attenuates aquaporin 3 overexpression induced by retinoic acid through inhibition of EGFR/ERK in cultured human skin keratinocytes.

    Science.gov (United States)

    Song, Xiuzu; Xu, Aie; Pan, Wei; Wallin, Brittany; Kivlin, Rebecca; Lu, Shan; Cao, Cong; Bi, Zhigang; Wan, Yinsheng

    2008-08-01

    The most common adverse effects that are related to all-trans retinoic acid (atRA) treatment are irritation and dryness of the skin. atRA therapy is reported to impair barrier function as achieved by trans-epidermal water loss (TEWL). Treatment with nicotinamide prior to initiation of atRA therapy provides additional barrier protection and thus reduces susceptibility of retinoic acid. Our previous studies showed that atRA upregulates aquaporin 3 (AQP3) in cultured human skin keratinocytes and fibroblasts. Others have demonstrated that in atopic dermatitis, overexpression of AQP3 is linked to elevated TEWL and that nicotinamide treatment reduces skin TEWL. In this study, we observed that while atRA upregulates AQP3 expression in cultured human skin keratinocytes (HaCaT cells), nicotinamide attenuates the effect of atRA in a concentration-dependent manner. atRA treatment induces EGFR and ERK activation. PD153035, an EGFR inhibitor, and U0126, an ERK inhibitor, inhibit atRA-induced upregulation of AQP3. Nicotinamide also inhibits atRA-induced activation of EGFR/ERK signal transduction and decreases water permeability by downregulating AQP3 expression. Collectively, our results indicate that the effect of atRA on AQP3 expression is at least partly mediated by EGFR/ERK signaling in cultured human skin keratinocytes. Nicotinamide attenuates atRA-induced AQP3 expression through inhibition of EGFR/ERK signal transduction and eventually decreases water permeability and water loss. Our study provides insights into the molecular mechanism through which nicotinamide reverses the side effects of dryness in human skin after treatment with atRA.

  14. On characterizing terrain visibility graphs

    Directory of Open Access Journals (Sweden)

    William Evans

    2015-06-01

    Full Text Available A terrain is an $x$-monotone polygonal line in the $xy$-plane. Two vertices of a terrain are mutually visible if and only if there is no terrain vertex on or above the open line segment connecting them. A graph whose vertices represent terrain vertices and whose edges represent mutually visible pairs of terrain vertices is called a terrain visibility graph. We would like to find properties that are both necessary and sufficient for a graph to be a terrain visibility graph; that is, we would like to characterize terrain visibility graphs.Abello et al. [Discrete and Computational Geometry, 14(3:331--358, 1995] showed that all terrain visibility graphs are “persistent”. They showed that the visibility information of a terrain point set implies some ordering requirements on the slopes of the lines connecting pairs of points in any realization, and as a step towards showing sufficiency, they proved that for any persistent graph $M$ there is a total order on the slopes of the (pseudo lines in a generalized configuration of points whose visibility graph is $M$.We give a much simpler proof of this result by establishing an orientation to every triple of vertices, reflecting some slope ordering requirements that are consistent with $M$ being the visibility graph, and prove that these requirements form a partial order. We give a faster algorithm to construct a total order on the slopes. Our approach attempts to clarify the implications of the graph theoretic properties on the ordering of the slopes, and may be interpreted as defining properties on an underlying oriented matroid that we show is a restricted type of $3$-signotope.

  15. Visible light assisted photodecolorization of eosin-Y in aqueous solution using hesperidin modified TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Vignesh, K. [P.G. and Research Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625009 (India); Suganthi, A., E-mail: suganthiphd09@gmail.com [P.G. and Research Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625009 (India); Rajarajan, M., E-mail: rajarajan_1962@yahoo.com [Department of Chemistry, C.P.A. College, Bodinayakanur, Tamilnadu 626513 (India); Sakthivadivel, R. [P.G. and Research Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625009 (India)

    2012-03-01

    Hesperidin a flavanoid, modified TiO{sub 2} nanoparticles (Hes-TiO{sub 2}) was synthesized to improve the visible light driven photocatalytic performance of TiO{sub 2}. The synthesized nanoparticles were characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), FT-IR, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of Hes-TiO{sub 2} was investigated based on the decolorization of eosin-Y under visible light irradiation. Hes-TiO{sub 2} showed high efficiency for the decolorization of eosin-Y. The influences of various reaction parameters like effect of pH, catalyst dosage and initial dye concentration on the photocatalytic efficiency were investigated. The adsorption of eosin-Y on Hes-TiO{sub 2} was found favorable by the Langmuir approach. The removal percentage of chemical oxygen demand (COD) was determined to evaluate the mineralization of eosin-Y during photodecolorization. Based on the intermediates obtained in the GC-MS spectroscopic technique, a probable degradation mechanism has been proposed.

  16. Visible light assisted photodecolorization of eosin-Y in aqueous solution using hesperidin modified TiO2 nanoparticles

    Science.gov (United States)

    Vignesh, K.; Suganthi, A.; Rajarajan, M.; Sakthivadivel, R.

    2012-03-01

    Hesperidin a flavanoid, modified TiO2 nanoparticles (Hes-TiO2) was synthesized to improve the visible light driven photocatalytic performance of TiO2. The synthesized nanoparticles were characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), FT-IR, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of Hes-TiO2 was investigated based on the decolorization of eosin-Y under visible light irradiation. Hes-TiO2 showed high efficiency for the decolorization of eosin-Y. The influences of various reaction parameters like effect of pH, catalyst dosage and initial dye concentration on the photocatalytic efficiency were investigated. The adsorption of eosin-Y on Hes-TiO2 was found favorable by the Langmuir approach. The removal percentage of chemical oxygen demand (COD) was determined to evaluate the mineralization of eosin-Y during photodecolorization. Based on the intermediates obtained in the GC-MS spectroscopic technique, a probable degradation mechanism has been proposed.

  17. Incremental Visualizer for Visible Objects

    DEFF Research Database (Denmark)

    Bukauskas, Linas; Bøhlen, Michael Hanspeter

    path. IVVO is the novel solution which allows data to be visualized and loaded on the fly from the database and which regards visibilities of objects. We run a set of experiments to convince that IVVO is feasible in terms of I/O operations and CPU load. We consider the example of data which uses......This paper discusses the integration of database back-end and visualizer front-end into a one tightly coupled system. The main aim which we achieve is to reduce the data pipeline from database to visualization by using incremental data extraction of visible objects in a fly-through scenarios. We...... also argue that passing only relevant data from the database will substantially reduce the overall load of the visualization system. We propose the system Incremental Visualizer for Visible Objects (IVVO) which considers visible objects and enables incremental visualization along the observer movement...

  18. vysmaw: Fast visibility stream muncher

    Science.gov (United States)

    Pokorny, Martin; Law, Casey J.

    2017-10-01

    The vysmaw client library facilitates the development of code for processes to tap into the fast visibility stream on the National Radio Astronomy Observatory's Very Large Array correlator back-end InfiniBand network.

  19. Visible neutrino decay at DUNE

    Energy Technology Data Exchange (ETDEWEB)

    Coloma, Pilar [Fermilab; Peres, Orlando G. [ICTP, Trieste

    2017-05-09

    If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino oscillation experiments, a characteristic signature of such \\emph{visible neutrino decay} would be an apparent excess of events at low energies. We focus on a simple phenomenological model in which the heaviest neutrino decays as $\

  20. Computing Visible-Surface Representations,

    Science.gov (United States)

    1985-03-01

    of applications. @ Massachusetts Institute of Technology 1985 "’ki report dcs;crihrs rccarch done at the Arificial lInelligence lhaboratory of the...411FO111 OIMMI bm tpal) IS. SUPPLEMENTARY MOTES None A IS~~~1. KEY WORS (Co~me 01 reerseea ............ MIngUfy ySek It Vision Variational principles...perception of visible surfaces. The explicit representation of visible surfaces, an intermediate goal of computational vision , has since attracted

  1. Structural, spectroscopic and voltammetric studies of bis(acetazolamido)bis(aquo)bis(nicotinamide)copper(II)

    Science.gov (United States)

    Öztürk, Filiz; Bulut, Ahmet; Paşaoğlu, Hümeyra; Bulut, İclal; Büyükgüngör, Orhan

    2012-11-01

    Polymeric copper(II) complex, [Cu(Hacm)2(na)2(H2O)2] [H2acm; acetazolamide, na; nicotinamide] was synthesized and characterized by spectroscopic (IR; infrared spectroscopy, EPR; electron paramagnetic resonance), structural (XRD) and voltammetric structural (CV) methods. The copper(II) compound crystallizes in the triclinic space group P1¯, Z = 1, with the unit-cell dimensions: a = 7.672 (5) Å, b = 8.681 (5) Å, c = 11.938 (5) Å, α = 90.807 (7)°, β = 98.616 (5)° and γ = 110.647 (5)°. The Cu(II) ion has a distorted octahedral coordination geometry. The crystal packing of the complex is stabilized by intermolecular O-H…O and N-H…O hydrogen bonds. The powder EPR spectrum of copper(II) complex have indicate that the paramagnetic center is in a tetragonal symmetry with the Cu2+ ion having a distorted octahedral geometry. The vibrational investigation has been carried out on the basis of some characteristic IR bands of acetazolamide and nicotinamide molecules.

  2. Nicotinamide phosphoribosyltransferase may be involved in age-related brain diseases.

    Directory of Open Access Journals (Sweden)

    Li-Ying Liu

    Full Text Available Nicotinamide phosphoribosyltransferase (NAMPT is a key enzyme for nicotinamide adenine dinucleotide (NAD biosynthesis, and can be found either intracellularly (iNAMPT or extracellularly (eNAMPT. Studies have shown that both iNAMPT and eNAMPT are implicated in aging and age-related diseases/disorders in the peripheral system. However, their functional roles in aged brain remain to be established. Here we showed that upon aging, NAMPT level increased in serum but decreased in brain, decreased in cortex and hippocampus but remained unchanged in cerebellum and striatum in brain, and increased in microglia but likely decreased in neuron. Accordingly, total NAD (tNAD level significantly decreased in hippocampus, cerebellum and striatum in aged brain. Application of recombinant NAMPT, mimicking the elevated serum NAMPT level, enhanced the susceptibility of cerebral endothelial cells to ischemic injury, while inhibition of iNAMPT by FK866, a specific inhibitor, reduced intracellular NAD level and induced neuronal death. Taken together, we have revealed a region- and cell-specific change of NAMPT level in brain and serum upon aging, deduced its potential consequences, which suggests that NAMPT is a regulatory factor in aging and age-related brain diseases.

  3. Nicotinamide Riboside Is a Major NAD+ Precursor Vitamin in Cow Milk.

    Science.gov (United States)

    Trammell, Samuel Aj; Yu, Liping; Redpath, Philip; Migaud, Marie E; Brenner, Charles

    2016-05-01

    Nicotinamide riboside (NR) is a recently discovered NAD(+) precursor vitamin with a unique biosynthetic pathway. Although the presence of NR in cow milk has been known for more than a decade, the concentration of NR with respect to the other NAD(+) precursors was unknown. We aimed to determine NAD(+) precursor vitamin concentration in raw samples of milk from individual cows and from commercially available cow milk. LC tandem mass spectrometry and isotope dilution technologies were used to quantify NAD(+) precursor vitamin concentration and to measure NR stability in raw and commercial milk. Nuclear magnetic resonance (NMR) spectroscopy was used to test for NR binding to substances in milk. Cow milk typically contained ∼12 μmol NAD(+) precursor vitamins/L, of which 60% was present as nicotinamide and 40% was present as NR. Nicotinic acid and other NAD(+) metabolites were below the limits of detection. Milk from samples testing positive for Staphylococcus aureus contained lower concentrations of NR (Spearman ρ = -0.58, P = 0.014), and NR was degraded by S. aureus Conventional milk contained more NR than milk sold as organic. Nonetheless, NR was stable in organic milk and exhibited an NMR spectrum consistent with association with a protein fraction in skim milk. NR is a major NAD(+) precursor vitamin in cow milk. Control of S. aureus may be important to preserve the NAD(+) precursor vitamin concentration of milk. © 2016 American Society for Nutrition.

  4. YCL047C/POF1 is a novel nicotinamide mononucleotide adenylyltransferase (NMNAT) in Saccharomyces cerevisiae.

    Science.gov (United States)

    Kato, Michiko; Lin, Su-Ju

    2014-05-30

    NAD(+) is an essential metabolic cofactor involved in various cellular biochemical processes. Nicotinamide riboside (NR) is an endogenously produced key pyridine metabolite that plays important roles in the maintenance of NAD(+) pool. Using a NR-specific cell-based screen, we identified mutants that exhibit altered NR release phenotype. Yeast cells lacking the ORF YCL047C/POF1 release considerably more NR compared with wild type, suggesting that POF1 plays an important role in NR/NAD(+) metabolism. The amino acid sequence of Pof1 indicates that it is a putative nicotinamide mononucleotide adenylyltransferase (NMNAT). Unlike other yeast NMNATs, Pof1 exhibits NMN-specific adenylyltransferase activity. Deletion of POF1 significantly lowers NAD(+) levels and decreases the efficiency of NR utilization, resistance to oxidative stress, and NR-induced life span extension. We also show that NR is constantly produced by multiple nucleotidases and that the intracellular NR pools are likely to be compartmentalized, which contributes to the regulation of NAD(+) homeostasis. Our findings may contribute to the understanding of the molecular basis and regulation of NAD(+) metabolism in higher eukaryotes. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. YCL047C/POF1 Is a Novel Nicotinamide Mononucleotide Adenylyltransferase (NMNAT) in Saccharomyces cerevisiae*

    Science.gov (United States)

    Kato, Michiko; Lin, Su-Ju

    2014-01-01

    NAD+ is an essential metabolic cofactor involved in various cellular biochemical processes. Nicotinamide riboside (NR) is an endogenously produced key pyridine metabolite that plays important roles in the maintenance of NAD+ pool. Using a NR-specific cell-based screen, we identified mutants that exhibit altered NR release phenotype. Yeast cells lacking the ORF YCL047C/POF1 release considerably more NR compared with wild type, suggesting that POF1 plays an important role in NR/NAD+ metabolism. The amino acid sequence of Pof1 indicates that it is a putative nicotinamide mononucleotide adenylyltransferase (NMNAT). Unlike other yeast NMNATs, Pof1 exhibits NMN-specific adenylyltransferase activity. Deletion of POF1 significantly lowers NAD+ levels and decreases the efficiency of NR utilization, resistance to oxidative stress, and NR-induced life span extension. We also show that NR is constantly produced by multiple nucleotidases and that the intracellular NR pools are likely to be compartmentalized, which contributes to the regulation of NAD+ homeostasis. Our findings may contribute to the understanding of the molecular basis and regulation of NAD+ metabolism in higher eukaryotes. PMID:24759102

  6. Protecting axonal degeneration by increasing nicotinamide adenine dinucleotide levels in experimental autoimmune encephalomyelitis models.

    Science.gov (United States)

    Kaneko, Shinjiro; Wang, Jing; Kaneko, Marie; Yiu, Glenn; Hurrell, Joanna M; Chitnis, Tanuja; Khoury, Samia J; He, Zhigang

    2006-09-20

    Axonal damage is a major morphological alteration in the CNS of patients with multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). However, the underlying mechanism for the axonal damage associated with MS/EAE and its contribution to the clinical symptoms remain unclear. The expression of a fusion protein, named "Wallerian degeneration slow" (Wld(S)), can protect axons from degeneration, likely through a beta-nicotinamide adenine dinucleotide (NAD)-dependent mechanism. In this study, we find that, when induced with EAE, Wld(S) mice showed a modest attenuation of behavioral deficits and axon loss, suggesting that EAE-associated axon damage may occur by a mechanism similar to Wallerian degeneration. Furthermore, nicotinamide (NAm), an NAD biosynthesis precursor, profoundly prevents the degeneration of demyelinated axons and improves the behavioral deficits in EAE models. Finally, we demonstrate that delayed NAm treatment is also beneficial to EAE models, pointing to the therapeutic potential of NAm as a protective agent for EAE and perhaps MS patients.

  7. Preparation and characterization of alginate/silver/nicotinamide nanocomposites for treating diabetic wounds.

    Science.gov (United States)

    Montaser, A S; Abdel-Mohsen, A M; Ramadan, M A; Sleem, A A; Sahffie, N M; Jancar, J; Hebeish, A

    2016-11-01

    Silver/Alginate/Nicotinamide nanoparticles composite (Ag/ALG/Nic) was prepared and used for the first time to fabricate wound dressing material. Sodium alginate (ALG) was used as reducing and stabilizing agents for preparation of silver nanoparticles (Ag-NPs). Effect of concentrations of alginate (ALG) on the particle size of silver were studied and confirmed by different techniques like UV/vis spectroscopy, transmission electron microscope (TEM) and dynamic light scattering (DLS). Nonwoven viscous fabrics were used as a carrier for silver/alginate/nanoparticles composite by impregnated the nonwoven fabrics as per the padding-curing technique. Nicotinamide (Nic) as anti-inflammatory drug was entrapped into Ag-NPS/ALG/nonwoven fabrics. Scanning electron microscope and energy dispersive x-ray (SEM-EDX) were used to evaluate the presence of Ag/ALG/Nic nanoparticles composite anchored the nonwoven fabrics. The antibacterial activity of the Ag/ALG/Nic wound dressing material was evaluated against Escherichia coli (E. coli) and Staphylococcus Aureus (St. Aureus). The wound healing and histological studied were evaluated by using burn diabetic rat animals. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Nicotinamide phosphoribosyl transferase (Nampt) is required for de novo lipogenesis in tumor cells.

    Science.gov (United States)

    Bowlby, Sarah C; Thomas, Michael J; D'Agostino, Ralph B; Kridel, Steven J

    2012-01-01

    Tumor cells have increased metabolic requirements to maintain rapid growth. In particular, a highly lipogenic phenotype is a hallmark of many tumor types, including prostate. Cancer cells also have increased turnover of nicotinamide adenine dinucleotide (NAD(+)), a coenzyme involved in multiple metabolic pathways. However, a specific role for NAD(+) in tumor cell lipogenesis has yet to be described. Our studies demonstrate a novel role for the NAD(+)-biosynthetic enzyme Nicotinamide phosphoribosyltransferase (Nampt) in maintaining de novo lipogenesis in prostate cancer (PCa) cells. Inhibition of Nampt reduces fatty acid and phospholipid synthesis. In particular, short chain saturated fatty acids and the phosphatidylcholine (PC) lipids into which these fatty acids are incorporated were specifically reduced by Nampt inhibition. Nampt blockade resulted in reduced ATP levels and concomitant activation of AMP-activated protein kinase (AMPK) and phosphorylation of acetyl-CoA carboxylase (ACC). In spite of this, pharmacological inhibition of AMPK was not sufficient to fully restore fatty acid synthesis. Rather, Nampt blockade also induced protein hyperacetylation in PC-3, DU145, and LNCaP cells, which correlated with the observed decreases in lipid synthesis. Moreover, the sirtuin inhibitor Sirtinol, and the simultaneous knockdown of SIRT1 and SIRT3, phenocopied the effects of Nampt inhibition on fatty acid synthesis. Altogether, these data reveal a novel role for Nampt in the regulation of de novo lipogenesis through the modulation of sirtuin activity in PCa cells.

  9. Ulcer healing properties of different extracts of Origanum majorana in streptozotocin-nicotinamide induced diabetic rats

    Directory of Open Access Journals (Sweden)

    BP Pimple

    2012-08-01

    Full Text Available Objective: The aim of the present investigation was to evaluate the ulcer healing properties of different extracts of Origannum majorana, viz., hydrodistilled volatile oil (OMO, methanolic (OMM and aqueous extract (OMW in streptozotocin-nicotinamide induced diabetic rats. Methods: All the extracts were administered in different doses (100, 200 and 400 mg/kg, p.o. to investigate the ulcer healing potential. Streptozotocin (STZ; 65 mg/kg, i.p. along with nicotinamide (120 mg/kg, i.p. was used to induce non-insulin dependent diabetes mellitus in rats. Aspirin (200 mg/kg, i.p. was administered for initial 7 d to induce gastric ulcerations in the diabetic rats. Various biochemical markers of blood and tissue origin were estimated to compare the ulcer healing potential of these extracts. Results: The OMO and OMM exhibited dose dependent significant (P<0.01 ulcer healing property than the OMW. Additionally, the antidiabetic property of OMO and OMM was better than OMW. Conclusions: The OMO and OMM of Origanum majorana leaves can prove to be beneficial in the concomitant treatment of gastric ulcers and diabetes.

  10. Generation of 1:1 Carbamazepine:Nicotinamide cocrystals by spray drying.

    Science.gov (United States)

    Patil, Shashank P; Modi, Sameer R; Bansal, Arvind K

    2014-10-01

    The present study investigates the potential of spray drying as a technique for generation of pharmaceutical cocrystals. Carbamazepine-Nicotinamide cocrystal (CNC) was chosen as model cocrystal system for this study. Firstly, CNC was generated using liquid assisted grinding and used for generation of phase solubility diagram (PSD) and ternary phase diagram (TPD). Both PSD and TPD were carefully evaluated for phase behavior of CNC when equilibrated with solvent. The undersaturated region with respect to CNC, as depicted by TPD, was selected as target region to initiate cocrystallization experiments. Various points in this region, representative of different compositions of Carbamazepine, Nicotinamide and CNC, were selected and spray drying was carried out. The spray dried product was characterized for solid state properties and was compared with CNC generated by liquid assisted grinding. Spray drying successfully generated CNC of similar quality as those generated by liquid assisted grinding. Moreover, there was no significant impact of process variables on formation of CNC. Spray drying, owing to its simplicity and industrial scalability, can be a promising method for large scale cocrystal generation. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Visible-light-induced Ag/BiVO4 semiconductor with enhanced photocatalytic and antibacterial performance

    Science.gov (United States)

    Regmi, Chhabilal; Dhakal, Dipesh; Wohn Lee, Soo

    2018-02-01

    An Ag-loaded BiVO4 visible-light-driven photocatalyst was synthesized by the microwave hydrothermal method followed by photodeposition. The photocatalytic performance of the synthesized samples was evaluated on a mixed dye (methylene blue and rhodamine B), as well as bisphenol A in aqueous solution. Similarly, the disinfection activities of synthesized samples towards the Gram-negative Escherichia coli (E. coli) in a model cell were investigated under irradiation with visible light (λ ≥ 420 nm). The synthesized samples have monoclinic scheelite structure. Photocatalytic results showed that all Ag-loaded BiVO4 samples exhibited greater degradation and a higher mineralization rate than the pure BiVO4, probably due to the presence of surface plasmon absorption that arises due to the loading of Ag on the BiVO4 surface. The optimum Ag loading of 5 wt% has the highest photocatalytic performance and greatest stability with pseudo-first-order rate constants of 0.031 min‑1 and 0.023 min‑1 for the degradation of methylene blue and rhodamine B respectively in a mixture with an equal volume and concentration of each dye. The photocatalytic degradation of bisphenol A reaches 76.2% with 5 wt% Ag-doped BiVO4 within 180 min irradiation time. Similarly, the Ag-loaded BiVO4 could completely inactivate E. coli cells within 30 min under visible light irradiation. The disruption of the cell membrane as well as degradation of protein and DNA exhibited constituted evidence for antibacterial activity towards E. coli. Moreover, the bactericidal mechanisms involved in the photocatalytic disinfection process were systematically investigated.

  12. Replicatively senescent human fibroblasts reveal a distinct intracellular metabolic profile with alterations in NAD+ and nicotinamide metabolism.

    Science.gov (United States)

    James, Emma L; Lane, James A E; Michalek, Ryan D; Karoly, Edward D; Parkinson, E Kenneth

    2016-12-07

    Cellular senescence occurs by proliferative exhaustion (PEsen) or following multiple cellular stresses but had not previously been subject to detailed metabolomic analysis. Therefore, we compared PEsen fibroblasts with proliferating and transiently growth arrested controls using a combination of different mass spectroscopy techniques. PEsen cells showed many specific alterations in both the NAD+ de novo and salvage pathways including striking accumulations of nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) in the amidated salvage pathway despite no increase in nicotinamide phosphoribosyl transferase or in the NR transport protein, CD73. Extracellular nicotinate was depleted and metabolites of the deamidated salvage pathway were reduced but intracellular NAD+ and nicotinamide were nevertheless maintained. However, sirtuin 1 was downregulated and so the accumulation of NMN and NR was best explained by reduced flux through the amidated arm of the NAD+ salvage pathway due to reduced sirtuin activity. PEsen cells also showed evidence of increased redox homeostasis and upregulated pathways used to generate energy and cellular membranes; these included nucleotide catabolism, membrane lipid breakdown and increased creatine metabolism. Thus PEsen cells upregulate several different pathways to sustain their survival which may serve as pharmacological targets for the elimination of senescent cells in age-related disease.

  13. Accelerated radiotherapy, carbogen, and nicotinamide in glioblastoma multiforme: report of European Organization for Research and Treatment of Cancer trial 22933

    NARCIS (Netherlands)

    Miralbell, R.; Mornex, F.; Greiner, R.; Bolla, M.; Storme, G.; Hulshof, M.; Bernier, J.; Denekamp, J.; Rojas, A. M.; Pierart, M.; van Glabbeke, M.; Mirimanoff, R. O.

    1999-01-01

    A three-step phase I/II trial associating accelerated radiotherapy with carbogen (step 1, ARCO), with nicotinamide (step 2, ARN), or with both (step 3, ARCON) was conducted, the aim of which was to overcome the effects of proliferation and hypoxia as potential causes of tumor radioresistance in

  14. Maternal intake of fat, riboflavin and nicotinamide and the risk of having offspring with congenital heart defects

    NARCIS (Netherlands)

    Smedts, H.P.M.; Rakhshandehroo, M.; Verkleij-Hagoort, A.C.; Vries, de J.H.M.; Ottenkamp, J.; Steegers, E.A.P.; Steegers-Theunissen, R.P.M.

    2008-01-01

    With the exception of studies on folic acid, little evidence is available concerning other nutrients in the pathogenesis of congenital heart defects (CHDs). Fatty acids play a central role in embryonic development, and the B-vitamins riboflavin and nicotinamide are co-enzymes in lipid metabolism.

  15. (Semi-)quantitative analysis of reduced nicotinamide adenine dinucleotide fluorescence images of blood-perfused rat heart

    NARCIS (Netherlands)

    J.M.C.C. Coremans (Joanna); C. Ince (Can); H.A. Bruining (Hajo); G.J. Puppels (Gerwin)

    1997-01-01

    textabstractIn vivo analysis of the metabolic state of tissue by means of reduced nicotinamide adenine dinucleotide (NADH) fluorimetry is disturbed by tissue movements and by hemodynamic and oximetric effects. These factors cause changes in the absorption of ultraviolet (UV)

  16. Effect of coenzyme Q10 alone and its combination with metformin on streptozotocin-nicotinamide-induced diabetic nephropathy in rats.

    Science.gov (United States)

    Maheshwari, Rajesh A; Balaraman, R; Sen, Ashim K; Seth, A K

    2014-01-01

    This study was aimed to investigate the therapeutic potential of coenzyme Q10 and its combination with metformin on streptozotocin (STZ)-nicotinamide-induced diabetic nephropathy (DN). Type 2 diabetes in rats was induced with STZ-nicotinamide. The diabetic rats were treated with coenzyme Q10 (10 mg/kg, p.o.) alone or coenzyme Q10 + metformin. Various parameters of renal function tests such as serum creatinine, urea, uric acid, and markers of oxidative stress such as renal malondialdehyde (MDA) level, superoxide dismutase (SOD), and catalase (CAT) activities were measured. Tumor necrosis factor-α (TNF-α), myeloperoxidase (MPO) activity, transforming growth factor-β (TGF-β), and nitrite content were estimated in renal tissues. All treated animal were subjected to histopathological changes of kidney. Diabetic rats showed a significant reduction in renal function, which was reflected with an increase in serum urea, serum creatinine, uric acid. In addition, STZ-nicotinamide caused renal tubular damage with a higher MDA level, depletion of SOD and CAT activity and glutathione (GSH) level. Moreover, TNF-α, MPO activity, TGF-β, and nitrite content were significantly increased in diabetic rats, while treatment with coenzyme Q10 or metformin or their combination ameliorate STZ-nicotinamide induced renal damage due to improvement in renal function, oxidative stress, suppression of TNF-α, MPO activity, TGF-β and nitrite content along with histopathological changes. This finding suggests that the treatment with coenzyme Q10 or metformin showed significant renoprotective effect against STZ-nicotinamide-induced DN. However, concomitant administration of both showed a better renoprotective effect than coenzyme Q10 or metformin alone treatment.

  17. Analytical Method Validation and Determination of Pyridoxine, Nicotinamide, and Caffeine in Energy Drinks Using Thin Layer Chromatography-Densitometry

    Directory of Open Access Journals (Sweden)

    Florentinus Dika Octa Riswanto

    2015-03-01

    Full Text Available Food supplement which contains vitamins and stimulants such as caffeine were classified as energy drink. TLC-densitometry method was chosen to determine the pyridoxine, nicotinamide, and caffeine in the energy drink sample. TLC plates of silica gel 60 F254 was used as the stationary phase and methanol : ethyl acetate : ammonia 25% (134:77:10 was used as the mobile phase. The correlation coefficient for each pyridoxine, nicotinamide, and caffeine were 0.9982, 0.9997, and 0.9966, respectively. Detection and quantitation limits of from the three analytes were 4.05 and 13.51 µg/mL; 13.15 and 43.83 µg/mL; 5.43 and 18.11 µg/mL, respectively. The recovery of pyridoxine, nicotinamide, and caffeine were within the required limit range of 95-105%. The percent of RSD were below the limit value of 5.7% for caffeine and nicotinamide and 8% for pyridoxine. The content amount of pyridoxine in the sample 1 and 2 were 33.59 ± 0.981 and 30.29 ± 2.061 µg/mL, respectively. The content amount of nicotinamide in the sample 1 and 2 were 106.53 ± 3.521 and 98.20 ± 3.648 µg/mL, respectively. The content amount of caffeine in the sample 1 and 2 were 249.50 ± 5.080 and 252.80 ± 2.640 µg/mL, respectively. Robustness test results showed that the most optimal method conditions should be applied for the analysis.

  18. Visfatin impairs endothelium-dependent relaxation in rat and human mesenteric microvessels through nicotinamide phosphoribosyltransferase activity.

    Science.gov (United States)

    Vallejo, Susana; Romacho, Tania; Angulo, Javier; Villalobos, Laura A; Cercas, Elena; Leivas, Alejandra; Bermejo, Elena; Carraro, Raffaele; Sánchez-Ferrer, Carlos F; Peiró, Concepción

    2011-01-01

    Visfatin, also known as extracellular pre-B-cell colony-enhancing factor (PBEF) and nicotinamide phosphoribosyltransferase (Nampt), is an adipocytokine whose circulating levels are enhanced in metabolic disorders, such as type 2 diabetes mellitus and obesity. Circulating visfatin levels have been positively associated with vascular damage and endothelial dysfunction. Here, we investigated the ability of visfatin to directly impair vascular reactivity in mesenteric microvessels from both male Sprague-Dawley rats and patients undergoing non-urgent, non-septic abdominal surgery. The pre-incubation of rat microvessels with visfatin (50 and 100 ng/mL) did not modify the contractile response to noradrenaline (1 pmol/L to 30 µmol/L), as determined using a small vessel myograph. However, visfatin (10 to 100 ng/mL) concentration-dependently impaired the relaxation to acetylcholine (ACh; 100 pmol/L to 3 µmol/L), without interfering with the endothelium-independent relaxation to sodium nitroprusside (1 nmol/L to 3 µmol/L). In both cultured human umbilical vein endothelial cells and rat microvascular preparations, visfatin (50 ng/mL) stimulated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, as determined by lucigenin-derived chemiluminiscence. The relaxation to ACh impaired by visfatin was restored by the NADPH oxidase inhibitor apocynin (10 µmol/L). Additionally, the Nampt inhibitor APO866 (10 mmol/L to 10 µmol/L), but not an insulin receptor-blocking antibody, also prevented the stimulation of NADPH oxidase and the relaxation impairment elicited by visfatin. Accordingly, the product of Nampt activity nicotinamide mononucleotide (100 nmol/L to 1 mmol/L) stimulated endothelial NADPH oxidase activity and concentration-dependently impaired ACh-induced vasorelaxation. In human mesenteric microvessels pre-contracted with 35 mmol/L potassium chloride, the endothelium-dependent vasodilation to bradykinin (1 nmol/L to 3 µmol/L) was equally impaired by

  19. Visfatin impairs endothelium-dependent relaxation in rat and human mesenteric microvessels through nicotinamide phosphoribosyltransferase activity.

    Directory of Open Access Journals (Sweden)

    Susana Vallejo

    Full Text Available Visfatin, also known as extracellular pre-B-cell colony-enhancing factor (PBEF and nicotinamide phosphoribosyltransferase (Nampt, is an adipocytokine whose circulating levels are enhanced in metabolic disorders, such as type 2 diabetes mellitus and obesity. Circulating visfatin levels have been positively associated with vascular damage and endothelial dysfunction. Here, we investigated the ability of visfatin to directly impair vascular reactivity in mesenteric microvessels from both male Sprague-Dawley rats and patients undergoing non-urgent, non-septic abdominal surgery. The pre-incubation of rat microvessels with visfatin (50 and 100 ng/mL did not modify the contractile response to noradrenaline (1 pmol/L to 30 µmol/L, as determined using a small vessel myograph. However, visfatin (10 to 100 ng/mL concentration-dependently impaired the relaxation to acetylcholine (ACh; 100 pmol/L to 3 µmol/L, without interfering with the endothelium-independent relaxation to sodium nitroprusside (1 nmol/L to 3 µmol/L. In both cultured human umbilical vein endothelial cells and rat microvascular preparations, visfatin (50 ng/mL stimulated nicotinamide adenine dinucleotide phosphate (NADPH oxidase activity, as determined by lucigenin-derived chemiluminiscence. The relaxation to ACh impaired by visfatin was restored by the NADPH oxidase inhibitor apocynin (10 µmol/L. Additionally, the Nampt inhibitor APO866 (10 mmol/L to 10 µmol/L, but not an insulin receptor-blocking antibody, also prevented the stimulation of NADPH oxidase and the relaxation impairment elicited by visfatin. Accordingly, the product of Nampt activity nicotinamide mononucleotide (100 nmol/L to 1 mmol/L stimulated endothelial NADPH oxidase activity and concentration-dependently impaired ACh-induced vasorelaxation. In human mesenteric microvessels pre-contracted with 35 mmol/L potassium chloride, the endothelium-dependent vasodilation to bradykinin (1 nmol/L to 3 µmol/L was equally impaired

  20. Visfatin Impairs Endothelium-Dependent Relaxation in Rat and Human Mesenteric Microvessels through Nicotinamide Phosphoribosyltransferase Activity

    Science.gov (United States)

    Angulo, Javier; Villalobos, Laura A.; Cercas, Elena; Leivas, Alejandra; Bermejo, Elena; Carraro, Raffaele; Sánchez-Ferrer, Carlos F.; Peiró, Concepción

    2011-01-01

    Visfatin, also known as extracellular pre–B-cell colony–enhancing factor (PBEF) and nicotinamide phosphoribosyltransferase (Nampt), is an adipocytokine whose circulating levels are enhanced in metabolic disorders, such as type 2 diabetes mellitus and obesity. Circulating visfatin levels have been positively associated with vascular damage and endothelial dysfunction. Here, we investigated the ability of visfatin to directly impair vascular reactivity in mesenteric microvessels from both male Sprague-Dawley rats and patients undergoing non-urgent, non-septic abdominal surgery. The pre-incubation of rat microvessels with visfatin (50 and 100 ng/mL) did not modify the contractile response to noradrenaline (1 pmol/L to 30 µmol/L), as determined using a small vessel myograph. However, visfatin (10 to 100 ng/mL) concentration-dependently impaired the relaxation to acetylcholine (ACh; 100 pmol/L to 3 µmol/L), without interfering with the endothelium-independent relaxation to sodium nitroprusside (1 nmol/L to 3 µmol/L). In both cultured human umbilical vein endothelial cells and rat microvascular preparations, visfatin (50 ng/mL) stimulated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, as determined by lucigenin-derived chemiluminiscence. The relaxation to ACh impaired by visfatin was restored by the NADPH oxidase inhibitor apocynin (10 µmol/L). Additionally, the Nampt inhibitor APO866 (10 mmol/L to 10 µmol/L), but not an insulin receptor-blocking antibody, also prevented the stimulation of NADPH oxidase and the relaxation impairment elicited by visfatin. Accordingly, the product of Nampt activity nicotinamide mononucleotide (100 nmol/L to 1 mmol/L) stimulated endothelial NADPH oxidase activity and concentration-dependently impaired ACh-induced vasorelaxation. In human mesenteric microvessels pre-contracted with 35 mmol/L potassium chloride, the endothelium-dependent vasodilation to bradykinin (1 nmol/L to 3 µmol/L) was equally impaired by

  1. Life-Threatening Adverse Reaction after Self-Initiated, Off-Label Use of High Dose Nicotinamide for the Treatment of Friedreich’s Ataxia

    Directory of Open Access Journals (Sweden)

    Nicolas Garin

    2015-06-01

    Full Text Available A 40-year old woman, previously known for Friedreich’s ataxia, presented with shock, profound lactic acidosis and hepatic failure after ingestion of a high dose of nicotinamide, the amide form of vitamin B3. On her own initiative, she was taking up to 4.4 g per day of nicotinamide, after having learned the results of a phase 2 study suggesting a potential benefit in Friedreich’s ataxia. The outcome was good with supportive care and withdrawal of nicotinamide.

  2. Nanocomposite of exfoliated bentonite/g-C3N4/Ag3PO4 for enhanced visible-light photocatalytic decomposition of Rhodamine B.

    Science.gov (United States)

    Ma, Jianfeng; Huang, Daiqin; Zhang, Wenyi; Zou, Jing; Kong, Yong; Zhu, Jianxi; Komarneni, Sridhar

    2016-11-01

    Novel visible-light-driven heterojunction photocatalyst comprising exfoliated bentonite, g-C3N4 and Ag3PO4 (EB/g-C3N4/Ag3PO4) was synthesized by a facile and green method. The composites EB/g-C3N4/Ag3PO4 were characterized by X-ray diffraction, Transmission electron microscopy, Fourier transform infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy and the Brunauer, Emmett, and Teller (BET) surface area method. Under visible light irradiation, EB/g-C3N4/Ag3PO4 composites displayed much higher photocatalytic activity than that of either pure g-C3N4 or pure Ag3PO4 in the degradation of Rhodamine B (RhB). Among the hybrid photocatalysts, EB/g-C3N4/Ag3PO4 composite containing 20 wt% Ag3PO4 exhibited the highest photocatalytic activity for the decolorization of RhB. Under the visible-light irradiation, the RhB dye was completely decolorized in less than 60 min. The enhanced photocatalytic performance is attributed to the stable structure, enlarged surface area, strong adsorbability, strong light absorption ability, and high-efficiency separation rate of photoinduced electron-hole pairs. Our finding paves a way to design highly efficient and stable visible-light-induced photocatalysts for practical applications in wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. N Doping to ZnO Nanorods for Photoelectrochemical Water Splitting under Visible Light: Engineered Impurity Distribution and Terraced Band Structure

    Science.gov (United States)

    Wang, Meng; Ren, Feng; Zhou, Jigang; Cai, Guangxu; Cai, Li; Hu, Yongfeng; Wang, Dongniu; Liu, Yichao; Guo, Liejin; Shen, Shaohua

    2015-01-01

    Solution-based ZnO nanorod arrays (NRAs) were modified with controlled N doping by an advanced ion implantation method, and were subsequently utilized as photoanodes for photoelectrochemical (PEC) water splitting under visible light irradiation. A gradient distribution of N dopants along the vertical direction of ZnO nanorods was realized. N doped ZnO NRAs displayed a markedly enhanced visible-light-driven PEC photocurrent density of ~160 μA/cm2 at 1.1 V vs. saturated calomel electrode (SCE), which was about 2 orders of magnitude higher than pristine ZnO NRAs. The gradiently distributed N dopants not only extended the optical absorption edges to visible light region, but also introduced terraced band structure. As a consequence, N gradient-doped ZnO NRAs can not only utilize the visible light irradiation but also efficiently drive photo-induced electron and hole transfer via the terraced band structure. The superior potential of ion implantation technique for creating gradient dopants distribution in host semiconductors will provide novel insights into doped photoelectrode materials for solar water splitting. PMID:26262752

  4. Effective visible light-active boron and europium co-doped BiVO4 synthesized by sol-gel method for photodegradion of methyl orange.

    Science.gov (United States)

    Wang, Min; Che, Yinsheng; Niu, Chao; Dang, Mingyan; Dong, Duo

    2013-11-15

    Eu-B co-doped BiVO4 visible-light-driven photocatalysts have been synthesized using the sol-gel method. The resulting materials were characterized by a series of joint techniques, including XPS, XRD, SEM, BET, and UV-vis DRS analyses. Compared with BiVO4 and B-BiVO4 photocatalysts, the Eu-B-BiVO4 photocatalysts exhibited much higher photocatalytic activity for methyl orange (MO) degradation under visible light irradiation. The optimal Eu doping content is 0.8 mol%. It was revealed that boron and europium were doped into the lattice of BiVO4 and this led to more surface oxygen vacancies, high specific surface areas, small crystallite size, a narrower band gap and intense light absorbance in the visible region. The doped Eu(III) cations can help in the separation of photogenerated electrons. The synergistic effects of boron and europium in doped BiVO4 were the main reason for improving visible light photocatalytic activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. An ion exchange strategy to BiOI/CH{sub 3}COO(BiO) heterojunction with enhanced visible-light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Han, Qiaofeng, E-mail: hanqiaofeng@njust.edu.cn; Yang, Zhen; Wang, Li; Shen, Zichen; Wang, Xin; Zhu, Junwu; Jiang, Xiaohong

    2017-05-01

    Highlights: • BiOI/BiOAc heterojunction was firstly synthesized by an ion exchange route. • BiOI/BiOAc exhibited enhanced visible-light-driven photoreactivity for the dyes degradation in comparison with individuals. • Photocatalytic activity of the as-prepared BiOI/BiOAc is better than that prepared by precipitation-deposition method. • Photosensitization effect of BiOI to BiOAc was superior to that of Bi{sub 2}S{sub 3} due to suitable solubility constant. - Abstract: It is very significant to develop CH{sub 3}COO(BiO) (denoted as BiOAc) based photocatalysts for the removal of pollutants due to its non-toxicity and availability. We previously reported that BiOAc exhibited excellent photocatalytic activity for rhodamine B (RhB) degradation under UV light irradiation. Herein, by an ion exchange approach, BiOI/BiOAc heterojunction could be easily obtained. The as-prepared heterojunction possessed enhanced photodegradation activity for multiple dyes including RhB and methyl orange (MO) under visible light illumination in comparison with individual materials. Good visible-light photocatalytic activity of the heterojunction could be attributed to the increased visible light response, effective charge transfer from the modified band position and close interfacial contact due to partial ion exchange method.

  6. Visibility of natural tertiary rainbows.

    Science.gov (United States)

    Lee, Raymond L; Laven, Philip

    2011-10-01

    Naturally occurring tertiary rainbows are extraordinarily rare and only a handful of reliable sightings and photographs have been published. Indeed, tertiaries are sometimes assumed to be inherently invisible because of sun glare and strong forward scattering by raindrops. To analyze the natural tertiary's visibility, we use Lorenz-Mie theory, the Debye series, and a modified geometrical optics model (including both interference and nonspherical drops) to calculate the tertiary's (1) chromaticity gamuts, (2) luminance contrasts, and (3) color contrasts as seen against dark cloud backgrounds. Results from each model show that natural tertiaries are just visible for some unusual combinations of lighting conditions and raindrop size distributions.

  7. Ultraviolet hypersensitivity of Cockayne syndrome lymphoblastoid lines - the effects of exogenous. beta. -nicotinamide adenine dinucleotide

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Fujio; Kukita, Atsushi

    1986-12-01

    Four Cockayne Syndrome (CS) lymphoblastoid lines were tested for the lethal effects of UV radiation (254 nm) with or without addition of exogenous ..beta..-nicotinamide adenine dinucleotide (..beta..-NAD/sup +/) to their culture medium. Two of them exhibited a small but significantly increased resistance to UV radiation when ..beta..-NAD/sup +/ was added to the culture. However, their UV sensitivity after ..beta..-NAD+ addition was still much greater than that of normal control lines. Normal control lymphoblastoid lines and those from complementation group A and group C of xeroderma pigmentosum (XP) did not reveal any differences in post-UV sensitivity after the addition of exogenous ..beta..-NAD/sup +/. Thus the abnormal response to the lethal effects of UV radiation of CS lymphoblastoid lines could not be rectified by ..beta..-NAD/sup +/ addition. However, ..beta..-NAD/sup +/ does appear to play some partial role in reducing the high UV sensitivity of some CS lymphoblastoid lines.

  8. Phosphoribulokinase from Nitrobacter winogradskyi: activation by reduced nicotinamide adenine dinucleotide and inhibition by pyridoxal phosphate.

    Science.gov (United States)

    Kiesow, L A; Lindsley, B F; Bless, J W

    1977-04-01

    CO2 fixation by particle-free extracts from Nitrobacter winogradskyi increased by addition of reduced nicotinamide adenine dinucleotide (NADH). Ribulose-1,5-diphosphate, however, increased CO2 fixation, even in the absence of NADH. Phosphoribulokinase (EC 2.7.1.19) was the enzyme of Nitrobacter extracts that was activated specifically by NADH. Pyridoxal-5-phosphate inhibited both CO2 fixation and NADH-activated phosphoribulokinase from Nitrobacter. However, it did not affect phosphoribulokinase from spinach leaves. Since the spinach enzyme had also no requirement for reduced pyridine nucleotides, it appears that pyridoxal phosphate interferes only with the binding of NADH and not with the binding of ribulose-5-phosphate and adenosine-5'-triphosphate. The regulation of phosphoribulokinase activity by NADH provided Nitrobacter with an energy-dependent control mechanism of CO2 assimilation.

  9. Combined patch containing salicylic acid and nicotinamide: role of drug interaction.

    Science.gov (United States)

    Padula, Cristina; Ferretti, Chiara; Nicoli, Sara; Santi, Patrizia

    2010-12-01

    The aim of the present study was to formulate a combined patch containing salicylic (SA) acid and nicotinamide (NA), useful for the treatment of mild acne, and to verify their mutual effect on drug permeation and skin retention. The performance of the patch was tested in vitro in permeation experiments using pig ear skin as barrier. To better understand the data obtained from the film, permeation from solutions and isopropyl myristate/water partition coefficient were also determined. The results obtained in the present work suggest a mutual influence of NA and SA on their permeation across the skin from an innovative transdermal film. The partition coefficient obtained when the two molecules were simultaneously present was typically lower than the respective value obtained with NA and SA alone.

  10. Insulin resistance and progression to type 1 diabetes in the European Nicotinamide Diabetes Intervention Trial (ENDIT)

    DEFF Research Database (Denmark)

    Bingley, Polly J; Mahon, Jeffrey L; Gale, Edwin A M

    2008-01-01

    OBJECTIVE: Insulin resistance can modulate progression to type 1 diabetes in individuals with ongoing islet autoimmunity. We wanted to see whether measures of insulin resistance improved risk assessment in islet cell antibody (ICA)-positive relatives when added to other immune and metabolic markers....... RESEARCH DESIGN AND METHODS: The retrospective cohort analysis included 213 family members participating in the European Nicotinamide Diabetes Intervention Trial. All were aged or=20 Juvenile Diabetes Foundation units. Median length of follow......-up was 4.21 years, and 105 individuals developed diabetes. Oral and intravenous glucose tolerance tests were performed at baseline; antibodies to GAD, IA-2, and insulin were determined by radioimmunoassay; and insulin resistance was estimated by homeostasis model assessment. Risk was assessed by Cox...

  11. Aspects of Tryptophan and Nicotinamide Adenine Dinucleotide in Immunity: A New Twist in an Old Tale

    Directory of Open Access Journals (Sweden)

    Hector Rodriguez Cetina Biefer

    2017-06-01

    Full Text Available Increasing evidence underscores the interesting ability of tryptophan to regulate immune responses. However, the exact mechanisms of tryptophan’s immune regulation remain to be determined. Tryptophan catabolism via the kynurenine pathway is known to play an important role in tryptophan’s involvement in immune responses. Interestingly, quinolinic acid, which is a neurotoxic catabolite of the kynurenine pathway, is the major pathway for the de novo synthesis of nicotinamide adenine dinucleotide (NAD + . Recent studies have shown that NAD + , a natural coenzyme found in all living cells, regulates immune responses and creates homeostasis via a novel signaling pathway. More importantly, the immunoregulatory properties of NAD + are strongly related to the overexpression of tryptophan hydroxylase 1 (Tph1. This review provides recent knowledge of tryptophan and NAD + and their specific and intriguing roles in the immune system. Furthermore, it focuses on the mechanisms by which tryptophan regulates NAD + synthesis as well as innate and adaptive immune responses.

  12. Photocatalytic Oxidation of Gaseous Isopropanol Using Visible-Light Active Silver Vanadates/SBA-15 Composite

    Directory of Open Access Journals (Sweden)

    Ting-Chung Pan

    2012-01-01

    Full Text Available An environmentally friendly visible-light-driven photocatalyst, silver vanadates/SBA-15, was prepared through an incipient wetness impregnation procedure with silver vanadates (SVO synthesized under a hydrothermal condition without a high-temperature calcination. The addition of mesoporous SBA-15 improves the formation of nanocrystalline silver vanadates. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS confirms the presence of Brønsted and Lewis acids on the SVO/SBA-15 composites. The results of photoluminescence spectra indicated that the electron-hole recombination rate have been effectively inhibited when SVO was loaded with mesoporous SBA-15. All the composites loaded with various amount of SVO inherit the higher adsorption capacity and larger mineralization yield than those of P-25 (commercial TiO2 and pure SVO. The sample loaded with 51% of SVO (51SVO/SBA-15 with mixed phases of Ag4V2O7 and α-Ag3VO4 exhibits the best photocatalytic activity. A favorable crystalline phase combined with high intensities of Brønsted and Lewis acids is considered the main cause of the enhanced adsorption capacity and outstanding photoactivity of the SVO/SBA-15 composites.

  13. Nicotinamide Phosphoribosyltransferase Upregulation by Phenylephrine Reduces Radiation Injury in Submandibular Gland

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Bin, E-mail: xiangbin72@163.com [Laboratory of Oral and Maxillofacial Disease, Second Hospital of Dalian Medical University, Dalian (China); Han, Lichi [Department of Oral Medicine and Medical Research Center of Medical College, Dalian University, Dalian (China); Wang, Xinyue [Laboratory of Oral and Maxillofacial Disease, Second Hospital of Dalian Medical University, Dalian (China); Tang, Ling [Life Sciences and Technology College, Dalian University, Dalian (China); Li, Kailiang [Department of Oral and Maxillofacial Surgery, Second Hospital of Dalian Medical University, Dalian (China); Li, Xiuxiu [Department of Oral Medicine and Medical Research Center of Medical College, Dalian University, Dalian (China); Zhao, Xibo [Department of Oral and Maxillofacial Surgery, Second Hospital of Dalian Medical University, Dalian (China); Xia, Miaomiao [Department of Oral Medicine and Medical Research Center of Medical College, Dalian University, Dalian (China); Zhou, Xixi [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, New Mexico (United States); Zhang, Fuyin [Department of Oral and Maxillofacial Surgery, Second Hospital of Dalian Medical University, Dalian (China); Liu, Ke Jian, E-mail: kliu@salud.unm.edu [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, New Mexico (United States)

    2016-11-01

    Purpose: Radiation therapy for head and neck cancer commonly leads to radiation sialadenitis. Emerging evidence has indicated that phenylephrine pretreatment reduces radiosensitivity in the salivary gland; however, the underlying cytoprotective mechanism remains unclear. Nicotinamide phosphoribosyltransferase (NAMPT) is not only a key enzyme for the nicotinamide adenine dinucleotide salvage pathway, but also a cytokine participating in cell survival, metabolism, and longevity, with a broad effect on cellular functions in physiology and pathology. However, the regulatory events of NAMPT in response to the irradiated salivary gland are unknown. Methods and Materials: The cell viability of primary cultured submandibular gland cells was determined using the PrestoBlue assay. NAMPT expression was measured using reverse transcriptase polymerase chain reaction and Western blotting in vitro and in vivo. Silent information regulator 1 (SIRT1) and phosphorylated Akt protein levels were examined by Western blotting. The cellular locations of NAMPT and SIRT1 were detected by immunohistochemistry. NAMPT promoter activity was assessed using the luciferase reporter gene assay. Results: NAMPT was mainly distributed in the cytoplasm of granular convoluted tubule cells and ductal cells in normal submandibular glands. mRNA and protein expression of NAMPT was downregulated after radiation but upregulated with phenylephrine pretreatment both in vivo and in vitro. Moreover, the protein expression of phosphorylated Akt and SIRT1 was decreased in irradiated glands, and phenylephrine pretreatment restored the expression of both. SIRT1 was mainly located in the cell nucleus and cytoplasm in the normal submandibular gland. Phenylephrine dramatically enhanced the expression of SIRT1, which was significantly reduced by radiation. Furthermore, phenylephrine induced a marked increase of NAMPT promoter activity. Conclusions: These findings reveal the regulatory mechanisms of NAMPT expression

  14. Sustained delivery of nicotinamide limits cortical injury and improves functional recovery following traumatic brain injury.

    Science.gov (United States)

    Goffus, Andrea M; Anderson, Gail D; Hoane, Michael

    2010-01-01

    Previously, we have demonstrated that nicotinamide (NAM), a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI). However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral controlled cortical impact (CCI) injuries or sham procedures and divided into three groups: CCI-NAM, CCI-vehicle, and sham. Thirty minutes following CCI, Alzet osmotic mini-pumps were implanted subcutaneously. NAM was delivered at a rate of 50 mg/kg/day for 7 days immediately post-CCI. On day 7 following injury, the pumps were removed and blood draws were collected for serum NAM and nicotinamide adenine dinucleotide (NAD+) analyses. Starting on day 2 post-CCI, animals were tested on a battery of sensorimotor tests (bilateral tactile adhesive removal, locomotor placing, and limb-use asymmetry). Continuous infusion of NAM resulted in a significant serum elevation in NAM, but not NAD+. Statistical analyses of the tactile removal and locomotor placing data revealed that continuous administration of NAM significantly reduced the initial magnitude of the injury deficit and improved overall recovery compared to the vehicle-treated animals. NAM treatment also significantly decreased limb-use asymmetries compared to vehicle-treated animals. The overall extent of the cortical damage was also reduced by NAM treatment. No detrimental effects were seen following continuous infusion. The present results suggest that NAM delivered via a clinically relevant therapeutic regimen may truncate behavioral damage following TBI. Thus our results offer strong support for translation into the clinical population.

  15. Sustained Delivery of Nicotinamide Limits Cortical Injury and Improves Functional Recovery Following Traumatic Brain Injury

    Directory of Open Access Journals (Sweden)

    Andrea M. Goffus

    2010-01-01

    Full Text Available Previously, we have demonstrated that nicotinamide (NAM, a neuroprotective soluble B-group vitamin, improves recovery of function following traumatic brain injury (TBI. However, no prior studies have examined whether NAM is beneficial following continuous infusions over 7 days post-TBI. The purpose of this study was to investigate the preclinical efficacy of NAM treatment as it might be delivered clinically; over several days by slow infusion. Rats were prepared with either unilateral controlled cortical impact (CCI injuries or sham procedures and divided into three groups: CCI-NAM, CCI-vehicle and sham. Thirty minutes following CCI, Alzet osmotic mini-pumps were implanted subcutaneously. NAM was delivered at a rate of 50 mg/kg/day for 7 days immediately post-CCI. On day 7 following injury, the pumps were removed and blood draws were collected for serum NAM and nicotinamide adenine dinucleotide (NAD+ analyses. Starting on day 2 post-CCI, animals were tested on a battery of sensorimotor tests (bilateral tactile adhesive removal, locomotor placing and limb-use asymmetry. Continuous infusion of NAM resulted in a significant serum elevation in NAM, but not NAD+. Statistical analyses of the tactile removal and locomotor placing data revealed that continuous administration of NAM significantly reduced the initial magnitude of the injury deficit and improved overall recovery compared to the vehicle-treated animals. NAM treatment also significantly decreased limb-use asymmetries compared to vehicle-treated animals. The overall extent of the cortical damage was also reduced by NAM treatment. No detrimental effects were seen following continuous infusion. The present results suggest that NAM delivered via a clinically relevant therapeutic regimen may truncate behavioral damage following TBI. Thus our results offer strong support for translation into the clinical population.

  16. Nicotinamide riboside, an unusual, non-typical, substrate of purified purine-nucleoside phosphorylases.

    Science.gov (United States)

    Wielgus-Kutrowska, B; Kulikowska, E; Wierzchowski, J; Bzowska, A; Shugar, D

    1997-01-15

    Nicotinamide 1-beta-D-riboside (Nir), the cationic, reducible moiety of the coenzyme NAD+, has been confirmed as an unusu