Drought tolerance and proteomics studies of transgenic wheat containing the maize C4 phosphoenolpyruvate carboxylase (PEPC) gene.

Science.gov (United States)

Qin, Na; Xu, Weigang; Hu, Lin; Li, Yan; Wang, Huiwei; Qi, Xueli; Fang, Yuhui; Hua, Xia

2016-11-01

Enhancing drought tolerance of crops has been a great challenge in crop improvement. Here, we report the maize phosphoenolpyruvate carboxylase (PEPC) gene was able to confer drought tolerance and increase grain yield in transgenic wheat (Triticum aestivum L.) plants. The improved of drought tolerance was associated with higher levels of proline, soluble sugar, soluble protein, and higher water use efficiency. The transgenic wheat plants had also a more extensive root system as well as increased photosynthetic capacity during stress treatments. The increased grain yield of the transgenic wheat was contributed by improved biomass, larger spike and grain numbers, and heavier 1000-grain weight under drought-stress conditions. Under non-stressed conditions, there were no significant increases in these of the measured traits except for photosynthetic rate when compared with parental wheat. Proteomic research showed that the expression levels of some proteins, including chlorophyll A-B binding protein and pyruvate, phosphate dikinase, which are related to photosynthesis, PAP fibrillin, which is involved in cytoskeleton synthesis, S-adenosylmethionine synthetase, which catalyzes methionine synthesis, were induced in the transgenic wheat under drought stress. Additionally, the expression of glutamine synthetase, which is involved in ammonia assimilation, was induced by drought stress in the wheat. Our study shows that PEPC can improve both stress tolerance and grain yield in wheat, demonstrating the efficacy of PEPC in crop improvement.

Mycobacterium tuberculosis Phosphoenolpyruvate Carboxykinase Is Regulated by Redox Mechanisms and Interaction with Thioredoxin

Czech Academy of Sciences Publication Activity Database

Machová, Iva; Snášel, Jan; Zimmermann, M.; Laubitz, D.; Plocinski, P.; Oehlmann, W.; Singh, M.; Dostál, Jiří; Sauer, U.; Pichová, Iva

2014-01-01

Roč. 289, č. 19 (2014), s. 13066-13078 ISSN 0021-9258 EU Projects: European Commission(XE) 241587 - SYSTEMTB Grant - others:OPPK(CZ) CZ.2.16/3.1.00/24016 Institutional support: RVO:61388963 Keywords : enzyme kinetics * hypoxia * metabolism * Mycobacterium tuberculosis * oxidation-reduction * thioredoxin * Phosphoenolpyruvate carboxykinase Subject RIV: CE - Biochemistry Impact factor: 4.573, year: 2014

Construction of g-C{sub 3}N{sub 4}/Al{sub 2}O{sub 3} hybrids via in-situ acidification and exfoliation with enhanced photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiao-jing [College of Science, Hebei University of Science and Technology, Shijiazhuang 050018 (China); State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Liu, Chao [College of Gemmology and Material Technics, Hebei GEO University, Shijiazhuang 050031 (China); Li, Xu-li [College of Science, Hebei University of Science and Technology, Shijiazhuang 050018 (China); Li, Fa-tang, E-mail: lifatang@126.com [College of Science, Hebei University of Science and Technology, Shijiazhuang 050018 (China); Li, Yu-pei [College of Science, Hebei University of Science and Technology, Shijiazhuang 050018 (China); Zhao, Jun [College of Science, Hebei University of Science and Technology, Shijiazhuang 050018 (China); State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Liu, Rui-hong [College of Science, Hebei University of Science and Technology, Shijiazhuang 050018 (China)

2017-02-01

Highlights: • Ultrathin g-C{sub 3}N{sub 4}/Al{sub 2}O{sub 3} hybrids are prepared via in-situ reaction. • The structure modification role of in-situ formed HNO{sub 3} for g-C{sub 3}N{sub 4} is found. • The ultrathin g-C{sub 3}N{sub 4} nanosheets are formed by the acidified melamine and Al(OH){sub 3}. • In-situ calcination of melamine and Al(OH){sub 3} benefits the contact of C{sub 3}N{sub 4} and Al{sub 2}O{sub 3}. • The activity of g-C{sub 3}N{sub 4}/Al{sub 2}O{sub 3} is 16.6 times that of pristine g-C{sub 3}N{sub 4} in degrading RhB. - Abstract: Homogeneous ultrathin g-C{sub 3}N{sub 4} nanosheets/Al{sub 2}O{sub 3} heterojunctions are synthesized using melamine and Al(NO{sub 3}){sub 3} via in-situ reaction and the following thermal polymerization approach. The in-situ reaction between melamine and Al(NO{sub 3}){sub 3} results in the existence of HNO{sub 3}-acidified melamine and Al(OH){sub 3} aggregates via the hydrolysis of Al(NO{sub 3}){sub 3}. After thermal polymerization, the aggregates are converted to g-C{sub 3}N{sub 4}/Al{sub 2}O{sub 3} composites. The thermal polymerization of acidified melamine and the support effect of aluminum hydroxide for g-C{sub 3}N{sub 4} during the calcination process lead to highly dispersed amrophous Al{sub 2}O{sub 3} on ultrathin g-C{sub 3}N{sub 4} nanosheets, which is beneficial for the separation of photogenerated electron-hole pairs in the heterojunction. The degradation rate for Rhodamine B (RhB) over the most activie sample is 16.6 times than that of pristine g-C{sub 3}N{sub 4} under visible light irradiation, which can be attributed to the high specific surface area, highly dispersion of amorphous Al{sub 2}O{sub 3} on ultrathin g-C{sub 3}N{sub 4} nanosheet, and the effective electrons transfer from g-C{sub 3}N{sub 4} to the amorphous Al{sub 2}O{sub 3}.

Extraction of in situ cosmogenic 14C from olivine

Science.gov (United States)

Pigati, J.S.; Lifton, N.A.; Timothy, Jull A.J.; Quade, Jay

2010-01-01

Chemical pretreatment and extraction techniques have been developed previously to extract in situ cosmogenic radiocarbon (in situ 14C) from quartz and carbonate. These minerals can be found in most environments on Earth, but are usually absent from mafic terrains. To fill this gap, we conducted numerous experiments aimed at extracting in situ 14C from olivine ((Fe,Mg)2SiO4). We were able to extract a stable and reproducible in situ 14C component from olivine using stepped heating and a lithium metaborate (LiBO2) flux, following treatment with dilute HNO3 over a variety of experimental conditions. However, measured concentrations for samples from the Tabernacle Hill basalt flow (17.3 ?? 0.3 ka4) in central Utah and the McCarty's basalt flow (3.0 ?? 0.2 ka) in western New Mexico were significantly lower than expected based on exposure of olivine in our samples to cosmic rays at each site. The source of the discrepancy is not clear. We speculate that in situ 14C atoms may not have been released from Mg-rich crystal lattices (the olivine composition at both sites was ~Fo65Fa35). Alternatively, a portion of the 14C atoms released from the olivine grains may have become trapped in synthetic spinel-like minerals that were created in the olivine-flux mixture during the extraction process, or were simply retained in the mixture itself. Regardless, the magnitude of the discrepancy appears to be inversely proportional to the Fe/(Fe+Mg) ratio of the olivine separates. If we apply a simple correction factor based on the chemical composition of the separates, then corrected in situ 14C concentrations are similar to theoretical values at both sites. At this time, we do not know if this agreement is fortuitous or real. Future research should include measurement of in situ 14C concentrations in olivine from known-age basalt flows with different chemical compositions (i.e. more Fe-rich) to determine if this correction is robust for all olivine-bearing rocks. ?? 2010 by the Arizona

Expression, purification and crystallization of an archaeal-type phosphoenolpyruvate carboxylase

International Nuclear Information System (INIS)

Dharmarajan, Lakshmi; Kraszewski, Jessica L.; Mukhopadhyay, Biswarup; Dunten, Pete W.

2009-01-01

The expression, purification, crystallization and preliminary diffraction analysis of an archaeal-type phosphoenolpyruvate carboxylase are described. Complete highly redundant X-ray data have been measured from a crystal diffracting to 3.13 Å resolution. An archaeal-type phosphoenolpyruvate carboxylase (PepcA) from Clostridium perfringens has been expressed in Escherichia coli in a soluble form with an amino-terminal His tag. The recombinant protein is enzymatically active and two crystal forms have been obtained. Complete diffraction data extending to 3.13 Å resolution have been measured from a crystal soaked in KAu(CN) 2 , using radiation at a wavelength just above the Au L III edge. The asymmetric unit contains two tetramers of PepcA

Ixodes scapularis Tick Cells Control Anaplasma phagocytophilum Infection by Increasing the Synthesis of Phosphoenolpyruvate from Tyrosine

Czech Academy of Sciences Publication Activity Database

Cabezas Cruz, Alejandro; Espinosa, P. J.; Obregon, D. A.; Alberdi, P.; de la Fuente, J.

2017-01-01

Roč. 7, AUG 17 (2017), č. článku 375. ISSN 2235-2988 Institutional support: RVO:60077344 Keywords : proteomics * transcriptomics * phosphoenolpyruvate * glycerol-3-phosphate * Ixodes scapularis * Anaplasma phagocytophilum Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.300, year: 2016

L-[4-11C]aspartic acid: enzymatic synthesis, myocardial uptake, and metabolism

International Nuclear Information System (INIS)

Barrio, J.R.; Egbert, J.E.; Henze, E.; Schelbert, H.R.; Baumgartner, F.J.

1982-01-01

Sterile, pyrogen-free L-[4- 11 C]aspartic acid was prepared from 11 CO 2 using phosphoenolpyruvate carboxylase and glutamic/oxaloacetic acid transaminase immobilized on Sepharose supports to determine if it is a useful indicator for in vivo, noninvasive determination of myocardial metabolism. An intracoronary bolus injection of L-[4- 11 C]aspartic acid into dog myocardium showed a triexponential clearance curve with maximal production of 11 CO 2 100 s after injection. Inactivation of myocardial transaminase activity modified the tracer clearance and inhibited the production of 11 CO 2 . Positron-computed tomography imaging showed that the 11 C activities retained in rhesus monkey myocardium are higher than those observed in dog heart after intravenous injection of L-[4- 11 C]aspartic acid. These findings demonstrated the rapid incorporation of the carbon skeleton of L-aspartic acid into the tricarboxylic acid cycle after enzymatic transamination in myocardium and suggested that L-[4- 11 C]aspartic acid could be of value for in vivo, noninvasive assessment of local myocardial metabolism

An update on in situ cosmogenic {sup 14}C analysis at ETH Zuerich

Energy Technology Data Exchange (ETDEWEB)

Hippe, K., E-mail: hippe@erdw.ethz.ch [Institute of Geochemistry and Petrology, ETH Zuerich, Zuerich CH-8092 (Switzerland); Kober, F. [Institute of Geology, ETH Zuerich, Zuerich CH-8092 (Switzerland); Wacker, L. [Institute for Particle Physics, ETH Zuerich, Zuerich CH-8093 (Switzerland); Fahrni, S.M. [Institute for Particle Physics, ETH Zuerich, Zuerich CH-8093 (Switzerland); Department of Chemistry and Biochemistry, University of Bern, Bern CH-3012 (Switzerland); Ivy-Ochs, S. [Institute for Particle Physics, ETH Zuerich, Zuerich CH-8093 (Switzerland); Akcar, N.; Schluechter, C. [Institute of Geological Sciences, University of Bern, Bern CH-3012 (Switzerland); Wieler, R. [Institute of Geochemistry and Petrology, ETH Zuerich, Zuerich CH-8092 (Switzerland)

2013-01-15

We present the improved performance of the modified in situ cosmogenic {sup 14}C extraction system at ETH Zuerich. Samples are now processed faster (2 days in total) and are measured with a high analytical precision of usually <2% using the gas ion source of the MICADAS AMS facility. Measurements of the PP-4 standard sample show a good reproducibility and consistency with published values. Procedural blanks are very low at currently {approx}4.0 Multiplication-Sign 10{sup 414}C atoms. Analyses of samples from a {approx}300 year old rock avalanche prove that we can successfully apply in situ{sup 14}C exposure dating to very young surfaces. Additionally, we present a modified calculation scheme for in situ{sup 14}C concentrations which differs from that used for conventional radiocarbon dating. This new approach explicitly accounts for the characteristics of in situ{sup 14}C production.

In situ loading of Ag_2WO_4 on ultrathin g-C_3N_4 nanosheets with highly enhanced photocatalytic performance

International Nuclear Information System (INIS)

Li, Yunfeng; Jin, Renxi; Fang, Xu; Yang, Yang; Yang, Man; Liu, Xianchun; Xing, Yan; Song, Shuyan

2016-01-01

Graphical abstract: Ultrathin g-C_3N_4 nanosheets (g-C_3N_4−NS) with improved electron transport ability and large number of active sites are employed instead of bulk g-C_3N_4 to prepare the Ag_2WO_4/g-C_3N_4−NS heterostructured photocatalysts, which exhibit remarkable photocatalytic activity for wastewater treatment. - Highlights: • Ag2WO4/g-C3N4-NS photocatalysts were obtained by a deposition-precipitation method. • Ag2WO4/g-C3N4-NS possess large surface areas and increased lifetime of charges. • Ag2WO4/g-C3N4-NS exhibit enhanced activity on degradation of RhB and MO. • The photocatalytic mechanism of the Ag2WO4/g-C3N4-NS system were investigated. - Abstract: The g-C_3N_4 nanosheets (g-C_3N_4−NS) exhibit more excellent property than common bulk g-C_3N_4 (g-C_3N_4-B) due to their large surface areas, improved electron transport ability and well dispersion in water. In this work, ultrathin g-C_3N_4−NS with a thickness of about 2.7 nm have been synthesized by a simple thermal exfoliation of bulk g-C_3N_4, and then Ag_2WO_4 nanoparticles are in situ loaded on their surface to construct the Ag_2WO_4/g-C_3N_4−NS heterostructured photocatalysts. Due to their unique physicochemical properties, the as-prepared heterostructures possess a fast interfacial charge transfer and increased lifetime of photo-excited charge carriers, and exhibit much higher photocatalytic activity. Under visible light irradiation, the optimum photocatalytic activity of Ag_2WO_4/g-C_3N_4−NS composites is almost 53.6 and 26.5 times higher than that of pure g-C_3N_4-B and Ag_2WO_4/g-C_3N_4-B heterostructures towards the degradation of rhodamine B, respectively, and is almost 30.6 and 9.8 times higher towards the degradation of methyl orange, respectively. In addition, the natural sunlight photocatalytic activities of the as-prepared samples are also investigated.

Microstructure and mechanical properties of in situ TiC and Nd2O3 particles reinforced Ti-4.5 wt.%Si alloy composites

International Nuclear Information System (INIS)

Zhang, Xinjiang; Li, Yibin; Song, Guangping; Sun, Yue; Peng, Qingyu; Li, Yuxin; He, Xiaodong

2011-01-01

Highlights: → (TiC + Nd 2 O 3 )/Ti-4.5 wt.%Si composites were in situ synthesized. → The phase components and microstructures of the composites were investigated. → In situ reinforcements improve the mechanical properties of the matrix alloy. -- Abstract: (TiC + Nd 2 O 3 )/Ti-4.5 wt.%Si composites were in situ synthesized by a non-consumable arc-melting technology. The phases in the composites were identified by X-ray diffraction. Microstructures of the composites were observed by optical microscope and scanning electron microscope. The composite contains four phases: TiC, Nd 2 O 3 , Ti 5 Si 3 and Ti. The TiC and Nd 2 O 3 particles with dendritic and near-equiaxed shapes are well distributed in Ti-4.5 wt.%Si alloy matrix, and the fine Nd 2 O 3 particles exist in the network Ti + Ti 5 Si 3 eutectic cells and Ti matrix of the composites. The hardness and compressive strength of the composites are markedly higher than that of Ti-4.5 wt.%Si alloy. When the TiC content is fixed as 10 wt.% in the composites, the hardness is enhanced as the Nd 2 O 3 content increases from 8 wt.% to 13 wt.%, but the compressive strength peaks at the Nd 2 O 3 content of 8 wt.%.

Improvement of Escherichia coli production strains by modification of the phosphoenolpyruvate:sugar phosphotransferase system

Directory of Open Access Journals (Sweden)

Gosset Guillermo

2005-05-01

Full Text Available Abstract The application of metabolic engineering in Escherichia coli has resulted in the generation of strains with the capacity to produce metabolites of commercial interest. Biotechnological processes with these engineered strains frequently employ culture media containing glucose as the carbon and energy source. In E. coli, the phosphoenolpyruvate:sugar phosphotransferase system (PTS transports glucose when this sugar is present at concentrations like those used in production fermentations. This protein system is involved in phosphoenolpyruvate-dependent sugar transport, therefore, its activity has an important impact on carbon flux distribution in the phosphoenolpyruvate and pyruvate nodes. Furthermore, PTS has a very important role in carbon catabolite repression. The properties of PTS impose metabolic and regulatory constraints that can hinder strain productivity. For this reason, PTS has been a target for modification with the purpose of strain improvement. In this review, PTS characteristics most relevant to strain performance and the different strategies of PTS modification for strain improvement are discussed. Functional replacement of PTS by alternative phosphoenolpyruvate-independent uptake and phosphorylation activities has resulted in significant improvements in product yield from glucose and productivity for several classes of metabolites. In addition, inactivation of PTS components has been applied successfully as a strategy to abolish carbon catabolite repression, resulting in E. coli strains that use more efficiently sugar mixtures, such as those obtained from lignocellulosic hydrolysates.

Spectroscopic studies of phosphoenolpyruvate carboxykinase from Mycobacterium tuberculosis

Czech Academy of Sciences Publication Activity Database

Bednárová, Lucie; Machová, Iva; Snášel, Jan; Dostál, Jiří; Hubálek, Martin; Pichová, Iva

2015-01-01

Roč. 22, č. 1 (2015), s. 16 ISSN 1211-5894. [Discussions in Structural Molecular Biology. Annual Meeting of the Czech Society for Structural Biology /13./. 19.03.2015-21.03.2015, Nové Hrady] R&D Projects: GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : phosphoenolpyruvate carboxykinase * structure * thiol * Raman spectroscopy * circular dichroism Subject RIV: CE - Biochemistry

Escherichia coli Phosphoenolpyruvate-Dependent Phosphotransferase System. Functional Asymmetry in Enzyme I Subunits Demonstrated by Reaction with 3-Bromopyruvate

NARCIS (Netherlands)

Hoeve-Duurkens, Ria ten; Robillard, George T.

1984-01-01

In the bacterial phosphoenolpyruvate-dependent sugar transport systems, enzyme I (EI) is responsible for the initial reaction step which is the transfer of the phosphoryl group from phosphoenolpyruvate to a cytoplasmic phosphocarrier protein (HPr). The inactivation of enzyme I by the substrate

Characterization and electrochemical performances of MoO2 modified LiFePO4/C cathode materials synthesized by in situ synthesis method

International Nuclear Information System (INIS)

He, Jichuan; Wang, Haibin; Gu, Chunlei; Liu, Shuxin

2014-01-01

Graphical abstract: The MoO 2 modified LiFePO 4 /C cathode materials were synthesized by in situ synthesis method. MoO 2 can sufficiently coat on the LiFePO 4 /C particles surface and does not alter LiFePO 4 crystal structure, and the adding of MoO 2 decreases the particles size and increases the tap density of cathode materials. The existence of MoO 2 improves electrochemical performance of LiFePO 4 cathode materials in specific capability and lithium ion diffusion and charge transfer resistance of cathode materials. - Highlights: • The MoO 2 modified LiFePO 4 /C cathode materials were synthesized by in situ synthesis method. • The existence of MoO 2 decreases the particles size and increases the tap density of cathode materials. • MoO 2 can sufficiently coat on the surface of LiFePO 4 /C cathode materials. • The existence of MoO 2 enhanced electrochemical performance of LiFePO 4 /C cathode materials. - Abstract: The MoO 2 modified LiFePO 4 /C cathode materials were synthesized by in situ synthesis method. Phase compositions and microstructures of the products were characterized by X-ray powder diffraction (XRD), SEM, TEM and EDS. Results indicate that MoO 2 can sufficiently coat on the LiFePO 4 surface and does not alter LiFePO 4 crystal structure, the existence of MoO 2 decreases the particles size and increases the tap density of cathode materials. The electrochemical behavior of cathode materials was analyzed using galvanostatic measurement, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that the existence of MoO 2 improves electrochemical performance of LiFePO 4 cathode materials in specific capability and lithium ion diffusion and charge transfer resistance. The initial charge–discharge specific capacity and apparent lithium ion diffusion coefficient increase, the charge transfer resistance decreases with MoO 2 content and maximizes around the MoO 2 content is 5 wt%. It has been had further proved that

In situ synthesis of TiB2-TiC particulates locally reinforced medium carbon steel-matrix composites via the SHS reaction of Ni-Ti-B4C system during casting

International Nuclear Information System (INIS)

Wang, H.Y.; Huang, L.; Jiang, Q.C.

2005-01-01

The fabrication of medium carbon steel-matrix composites locally reinforced with in situ TiB 2 -TiC particulates using self-propagating high-temperature synthesis (SHS) reaction of Ni-Ti-B 4 C system during casting was investigated. X-ray diffraction (XRD) results reveal that the exotherm of 1042 deg. C initiated by heat release of the solid state reaction in the differential thermal analysis (DTA) curve is an incomplete reaction in Ni-Ti-B 4 C system. As-cast microstructures of the in situ processed composites reveal a relatively uniform distribution of TiB 2 -TiC particulates in the locally reinforced regions. Furthermore, the particulate size and micro-porosity in the locally reinforced regions are significantly decreased with the increasing of the Ni content in the preforms. For a Ni content of 30 and 40 wt.%, near fully dense composites locally reinforced with in situ TiB 2 and TiC particulates can be fabricated. Although most of fine TiB 2 and TiC particulates which form by the reaction-precipitation mechanism during SHS reaction are present in the locally reinforced region, some large particulates which form by the nucleation-growth mechanism during solidification are entrapped inside the Fe-rich region located in the reinforcing region or inside the matrix region nearby the interface between matrix and reinforcing region. The hardness of the reinforcing region in the composite is significantly higher than that of the unreinforced medium carbon steel. Furthermore, the hardness values of the composites synthesized from 30 to 40 wt.% Ni-Ti-B 4 C systems are higher than those of the composites synthesized from 10 to 20 wt.% Ni-Ti-B 4 C systems

Mapping 3D genome architecture through in situ DNase Hi-C.

Science.gov (United States)

Ramani, Vijay; Cusanovich, Darren A; Hause, Ronald J; Ma, Wenxiu; Qiu, Ruolan; Deng, Xinxian; Blau, C Anthony; Disteche, Christine M; Noble, William S; Shendure, Jay; Duan, Zhijun

2016-11-01

With the advent of massively parallel sequencing, considerable work has gone into adapting chromosome conformation capture (3C) techniques to study chromosomal architecture at a genome-wide scale. We recently demonstrated that the inactive murine X chromosome adopts a bipartite structure using a novel 3C protocol, termed in situ DNase Hi-C. Like traditional Hi-C protocols, in situ DNase Hi-C requires that chromatin be chemically cross-linked, digested, end-repaired, and proximity-ligated with a biotinylated bridge adaptor. The resulting ligation products are optionally sheared, affinity-purified via streptavidin bead immobilization, and subjected to traditional next-generation library preparation for Illumina paired-end sequencing. Importantly, in situ DNase Hi-C obviates the dependence on a restriction enzyme to digest chromatin, instead relying on the endonuclease DNase I. Libraries generated by in situ DNase Hi-C have a higher effective resolution than traditional Hi-C libraries, which makes them valuable in cases in which high sequencing depth is allowed for, or when hybrid capture technologies are expected to be used. The protocol described here, which involves ∼4 d of bench work, is optimized for the study of mammalian cells, but it can be broadly applicable to any cell or tissue of interest, given experimental parameter optimization.

Facile in situ hydrothermal synthesis of g-C{sub 3}N{sub 4}/SnS{sub 2} composites with excellent visible-light photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Deng, Fang; Zhao, Lina; Pei, Xule [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang 330063 (China); College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Xubiao, E-mail: luoxubiao@126.com [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang 330063 (China); College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian, E-mail: sllou@hnu.edu.cn [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang 330063 (China); College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

2017-03-01

The g-C{sub 3}N{sub 4}/SnS{sub 2} composites were prepared by in situ hydrothermal method, and the effect of g-C{sub 3}N{sub 4} content on the physical and chemical properties, and photocatalytic performance of g-C{sub 3}N{sub 4}/SnS{sub 2} composites was investigated. The introduction of g-C{sub 3}N{sub 4} enhanced the visible-light absorption of SnS{sub 2}, and reduced the recombination rate of electron-hole pairs. The photocatalytic performance of g-C{sub 3}N{sub 4}/SnS{sub 2} composites was also obviously influenced by g-C{sub 3}N{sub 4} content, and it was found that 15% g-C{sub 3}N{sub 4}/SnS{sub 2} composite exhibited the highest photocatalytic activity and excellent regeneration, which was attributed to the most efficient charge separation, the largest specific surface area and the formation of dominant active species (h{sup +} and ·O{sub 2}{sup −} radicals) during the photocatalytic process. - Graphical abstract: Photocatalytic mechanism of g-C{sub 3}N{sub 4}/SnS{sub 2} composites. - Highlights: • g-C{sub 3}N{sub 4}/SnS{sub 2} composites were fabricated by a in situ hydrothermal process. • g-C{sub 3}N{sub 4} content was optimized, and the optimal g-C{sub 3}N{sub 4} content is 15%. • 15% g-C{sub 3}N{sub 4}/SnS{sub 2} shows the highest visible-light photocatalytic activity. • g-C{sub 3}N{sub 4}/SnS{sub 2} composites exhibit excellent reusability.

In situ one-pot fabrication of g-C3N4 nanosheets/NiS cocatalyst heterojunction with intimate interfaces for efficient visible light photocatalytic H2 generation

Science.gov (United States)

He, Kelin; Xie, Jun; Li, Mingli; Li, Xin

2018-02-01

Constructing high-quality earth-abundant semionconductor/cocatalyst heterojunction remains a grand challenge in the promising fields of photocatalytic solar fuel H2 production. Herein, an intimate g-C3N4 nanosheet/NiS cocatalyst heterojunction is fabricated by in situ one-step calcination of urea, thiourea and nickel acetate. Interestingly, thiourea could act as both the precursor of g-C3N4 and the sulfur source of NiS. The H2-evolution activity of as-obtained photocatalysts was tested in a triethanolamine (TEOA) scavenger solution under visible light irradiation. Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) mapping analysis clearly demonstrated that the NiS catalyst nanoparticles could be in situ fabricated and homogeneously distributed on the surface of g-C3N4 nanosheets without an obvious aggregation. The maximum H2-production rate of 29.68 μmol h-1 could be achieved, which is nearly comparable to that of 0.5 wt% Pt loaded sample. It is believed that the intimate heterojunction interfaces between NiS nanoparticles and g-C3N4 nanosheets could be in situ constructed by high temperature calcination, which achieved the improved charge separation, the enhanced oxidation ability of TEOA and the accelerated the sluggish H2-evolution kinetics, thus resulting in the remarkably enhanced hydrogen evolution. Therefore, our study provides insights into constructing high-quality robust g-C3N4-based heterojunction material for photocatalytic applications by using a simple one-step in-situ calcination technique.

Superior performance of LiFePO{sub 4}/C with porous structure synthesized by an in situ polymerization restriction method for lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Chen, Jian, E-mail: chemcj@126.com [Department of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang 471023 (China); Zhao, Na [Department of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang 471023 (China); Li, Guo-Dong, E-mail: lgd@jlu.edu.cn [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Guo, Fei-Fan [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Wang, Xiaofeng; Jia, Tiekun; Zhao, Junwei; Zhao, Yinggang; Wang, Xiaolin; Wan, Lin [Department of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang 471023 (China)

2016-09-01

A porous LiFePO{sub 4}/C nanocomposite was synthesized by an in situ polymerization restriction method. The obtained product possessed higher surface area and abundant pore structure. The physical and electrochemical properties of the LiFePO{sub 4}/C composite were investigated by X-ray diffraction, thermogravimetry analysis, nitrogen adsorption–desorption measurement, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy and electrochemical measurements. Electrochemical test indicated that the discharge capacity of LiFePO{sub 4}/C was as high as 156.1 mAh g{sup −1} in the first cycle at 0.5C and 145.2 mAh g{sup −1} after 50 cycles. The initial discharge capacities of the electrodes exhibited 126.3 mAh g{sup −1}, 108.6 mAh g{sup −1}, 82.5 mAh g{sup −1} and 62.8 mAh g{sup −1} at the high rates of 5C, 10C, 20C and 50C. The discharge capacity retentions after 500 cycles were 94.4%, 90.6%, 87.8% and 90.9% of the initial discharge capacity at rates of 5C, 10C, 20C and 50C, respectively. - Highlights: • The LiFePO{sub 4}/C composite was prepared by an in situ polymerization restriction method. • The crystallite growth of LiFePO{sub 4} can be effectively restricted and conductivity can be improved. • The LiFePO{sub 4}/C electrode shows excellent rate capability and cyclic performance.

Thermal annealing dynamics of carbon-coated LiFePO{sub 4} nanoparticles studied by in-situ analysis

Energy Technology Data Exchange (ETDEWEB)

Krumeich, Frank, E-mail: krumeich@inorg.chem.ethz.ch [Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich (Switzerland); Waser, Oliver; Pratsinis, Sotiris E. [Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich (Switzerland)

2016-10-15

The thermal behavior of core-shell carbon-coated lithium iron phosphate (LiFePO{sub 4}-C) nanoparticles made by flame spray pyrolysis (FSP) during annealing was investigated by in-situ transmission electron microscopy (TEM), in-situ X-ray powder diffraction (XRD) as well as ex-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Crystallization of the initially glassy LiFePO{sub 4}-C nanoparticles starts at quite low temperatures (T=400 °C), forming single crystals inside the confinement of the carbon shell. Upon increasing the temperature to T≥700 °C, LiFePO{sub 4} starts to diffuse through the carbon shell resulting in cavities inside the mostly intact carbon shell. By increasing the temperature further to T≥800 °C, the initial core-shell morphology converts into open carbon shells (flakes and cenospheres) and bulky LiFePO{sub 4} particles (diameter in the range 300–400 nm), in agreement with ex-situ experiments. - Graphical abstract: TEM images of a typical sample area recorded at room temperature and after heating in-situ heating reveal the growth of particles and the formation of empty carbon cages. - Highlights: • LiFePO{sub 4} coated by a carbon shell is produced by flame spray pyrolysis. • The amorphous LiFePO{sub 4} starts to crystallize at 400 °C as revealed by in-situ XRD. • Crystal growth was visualized by TEM heating experiments. • The formation of empty carbon cages starts at 700 °C.

Light-regulated phosphorylation of maize phosphoenolpyruvate carboxykinase plays a vital role in its activity.

Science.gov (United States)

Chao, Qing; Liu, Xiao-Yu; Mei, Ying-Chang; Gao, Zhi-Fang; Chen, Yi-Bo; Qian, Chun-Rong; Hao, Yu-Bo; Wang, Bai-Chen

2014-05-01

Phosphoenolpyruvate carboxykinase (PEPCK)-the major decarboxylase in PEPCK-type C4 plants-is also present in appreciable amounts in the bundle sheath cells of NADP-malic enzyme-type C4 plants, such as maize (Zea mays), where it plays an apparent crucial role during photosynthesis (Wingler et al., in Plant Physiol 120(2):539-546, 1999; Furumoto et al., in Plant Mol Biol 41(3):301-311, 1999). Herein, we describe the use of mass spectrometry to demonstrate phosphorylation of maize PEPCK residues Ser55, Thr58, Thr59, and Thr120. Western blotting indicated that the extent of Ser55 phosphorylation dramatically increases in the leaves of maize seedlings when the seedlings are transferred from darkness to light, and decreases in the leaves of seedlings transferred from light to darkness. The effect of light on phosphorylation of this residue is opposite that of the effect of light on PEPCK activity, with the decarboxylase activity of PEPCK being less in illuminated leaves than in leaves left in the dark. This inverse relationship between PEPCK activity and the extent of phosphorylation suggests that the suppressive effect of light on PEPCK decarboxylation activity might be mediated by reversible phosphorylation of Ser55.

Effects of an inhibitor of phosphoenolpyruvate carboxylase on photosynthesis of the terrestrial forms of amphibious Eleocharis species.

Science.gov (United States)

Ueno, Osamu; Ishimaru, Ken

2002-01-01

The leafless amphibious sedge Eleocharis vivipara develops culms with C(4) traits and Kranz anatomy under terrestrial conditions, but develops culms with C(3) traits and non-Kranz anatomy under submerged conditions. The culms of the terrestrial form have high C(4) enzyme activities, while those of the submerged form have decreased C(4) enzyme activities. The culms accumulate ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the mesophyll cells (MC) and the bundle sheath cells. The Rubisco in the MC may be responsible for the operation of the C(3) pathway in the submerged form. To verify the presence of the C(3) cycle in the MC, we examined the effects of 3,3-dichloro-2-(dihydroxyphosphinoylmethyl) -propenoate (DCDP), an inhibitor of phosphoenolpyruvate carboxylase (PEPC), on photosynthesis in culms of the terrestrial forms of E. vivipara and related amphibious species, E. baldwinii and E. retroflexa ssp. chaetaria. When 1 mM DCDP was fed via the transpiration stream to excised leaves, photosynthesis was inhibited completely in Fimbristylis dichotoma (C(4) control), but by only 20% in potato (C(3) control). In the terrestrial Eleocharis plants, the degree of inhibition of photosynthesis by DCDP was intermediate between those of the C(4) and C(3) plants, at 58-81%. These results suggest that photosynthesis under DCDP treatment in the terrestrial Eleocharis plants is due mainly to fixation of atmospheric CO(2) by Rubisco and probably the C(3) cycle in the MC. These features are reminiscent of those in C(4)-like plants. Differential effects of DCDP on photosynthesis of the 3 Eleocharis species are discussed in relation to differences in the degree of Rubisco accumulation and C(3) activity in the MC.

A simple enzymic method for the synthesis of [32P]phosphoenolpyruvate

International Nuclear Information System (INIS)

Parra, F.

1982-01-01

A rapid and simple enzymic method is described for the synthesis of [ 32 P]phosphoenolpyruvate from [ 32 P]Psub(i), with a reproducible yield of 74%. The final product was shown to be a good substrate for pyruvate kinase (EC 2.7.1.40). (author)

Chemical interaction of B4C, B, and C with Mo/Si layered structures

International Nuclear Information System (INIS)

Rooij-Lohmann, V. I. T. A. de; Veldhuizen, L. W.; Zoethout, E.; Yakshin, A. E.; Kruijs, R. W. E. van de; Thijsse, B. J.; Gorgoi, M.; Schaefers, F.; Bijkerk, F.

2010-01-01

To enhance the thermal stability, B 4 C diffusion barrier layers are often added to Mo/Si multilayer structures for extreme ultraviolet optics. Knowledge about the chemical interaction between B 4 C and Mo or Si, however is largely lacking. Therefore, the chemical processes during annealing up to 600 deg. C of a Mo/B 4 C/Si layered structure have been investigated in situ with hard x-ray photoelectron spectroscopy and ex situ with depth profiling x-ray photoelectron spectroscopy. Mo/B/Si and Mo/C/Si structures have also been analyzed as reference systems. The chemical processes in these systems have been identified, with two stages being distinguished. In the first stage, B and C diffuse and react predominantly with Mo. MoSi x forms in the second stage. If the diffusion barrier consists of C or B 4 C, a compound forms that is stable up to the maximum probed temperature and annealing time. We suggest that the diffusion barrier function of B 4 C interlayers as reported in literature can be caused by the stability of the formed compound, rather than by the stability of B 4 C itself.

The interval high rate discharge behavior of Li3V2(PO4)3/C cathode based on in situ polymerization method

International Nuclear Information System (INIS)

Mao, Wen-feng; Yan, Ji; Xie, Hui; Tang, Zhi-yuan; Xu, Qiang

2013-01-01

An in situ polymerization assisted fast sol–gel method was introduced to synthesize high performance Li 3 V 2 PO 4 /C (LVP/C) cathode material. The crystal structure, surface morphology and electrochemical performances of the LVP/C samples sintered at different temperatures were investigated. The composite sintered at 750 °C exhibits the highest specific discharge capacity of 119.02 mAh g −1 (440.35 Wh g −1 ) at 10 C rate. The Li + diffusion coefficient ranges from 10 −6 to 10 −8 cm 2 s −1 based on different scanning rates and the electronic conductivity is about 10 −5 S cm −1 . For comparison, an ex situ polymerization method was also employed to obtain the LVP/C composite. A novel charge/discharge testing mode was designed to investigate the electrochemical behavior of the as-prepared LVP/C composite for practical application in electric vehicle cells. The obtained high power density and the special testing mode prove the LVP/C composite would be a promising candidate for the electric vehicle application and deserves further investigation

Reaction of phosphoenolpyruvate carboxylase with (Z)-3-bromophosphoenolpyruvate and (Z)-3-fluorophosphoenolpyruvate

International Nuclear Information System (INIS)

Diaz, E.; O'Laughlin, J.T.; O'Leary, M.H.

1988-01-01

(Z)-3-Bromophosphoenolpyruvate inactivates phosphoenolpyruvate carboxylase from maize in the presence of HCO 3 - and either Mg 2+ or Mn 2+ . The inactivation rate follows saturation kinetics. Inactivation is slower in the presence of phospholactate or epoxymaleate, both of which are inhibitors of the enzyme, or dithiothreitol. Inactivation is completely prevented by the presence of lactate dehydrogenase and NADH, and 3-bromolactate is formed during this treatment. If the reaction is conducted by using HC 18 O 3 - , the inorganic phosphate produced contains 18 O. This and other evidence indicate that phosphoenolpyruvate carboxylase catalyzes conversion of bromophosphoenolpyruvate into bromopyruvate by way of the usual carboxyphosphate-enolate intermediate, and bromopyruvate is the species responsible for enzyme inactivation. (Z)-3-fluorophosphoenolpyruvate is transformed by the enzyme into a 6:1 mixture of 3-fluoropyruvate and 3-fluorooxalacetate, presumably by the same mechanism. The enzyme is not inactivated during this treatment

Photoperiodism and Crassulacean acid metabolism : III. Different characteristics of the photoperiod-sensitive and non-sensitive isoforms of phosphoenolpyruvate carboxylase and Crassulacean acid metabolism operation.

Science.gov (United States)

Brulfert, J; Queiroz, O

1982-05-01

Sensitivity to glucose-6-P, inorganic phosphate and malate, Km phosphoenolpyruvate (PEP), and the effect of pH were comparatively investigated for phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) extracted along the day-night cycle from leaves of Kalanchoe blossfeldiana v. Poelln. Tom Thumb, grown under different photoperiodic conditions. Under long days, sensitivity to effectors is weak and varies only slightly during the 24h cycle, together with small variations of Km (PEP), ranging from 1.2 to 1.8 mM. The response-curve to pH shows two peaks for pH 7.4 and 8.4. Transfer of the plants to short days established an increase in the sensitivity of the enzyme to the effectors together with the appearance of a day-night variation of this effect, maximum during the day. A clear diurnal oscillation of Km (PEP) is observed from 3.1 mM at the beginning of day (09.00 h) to 0.9 mM at midnight (00.00 h), at pH 7.4. These results complement previous electrophoretic and immunological data by affording enzyme kinetic evidence that short days induce a PEP carboxylase form responsible for full-Crassulacean acid metabolism (CAM) operation which is kinetically different from the photoperiod-sensitive, C3-like form prevailing in young leaves under long days. The results indicate that diurnal enzymic rhythms would improve the efficiency of the metabolic regulatory mechanisms and act as a coordinating factor for the daily and seasonal adaptive operation of CAM.

Enzyme II/sup Mtl/ of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system: identification of the activity-linked cysteine on the mannitol carrier

International Nuclear Information System (INIS)

Pas, H.H.; Robillard, G.T.

1988-01-01

The cysteine of the membrane-bound mannitol-specific enzyme II (EII/sup Mtl/) of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system have been labeled with 4-vinylpyridine. After proteolytic breakdown and reversed-phase HPLC, the peptides containing cysteines 110, 384, and 571 could be identified. N-Ethylmaleimide (NEM) treatment of the native unphosphorylated enzyme results in incorporation of one NEM label per molecule and loss of enzymatic activity. NEM treatment and inactivation prevented 4-vinylpyridine incorporation into the Cys-384-containing peptide, identifying this residue as the activity-linked cysteine. Both oxidation and phosphorylation of the native enzyme protected the enzyme against NEM labeling of Cys-384. Positive identification of the activity-linked cysteine was accomplished by inactivation with [ 14 C]iodoacetamide, proteolytic fragmentation, isolation of the peptide, and amino acid sequencing

In situ observation of mechanical damage within a SiC-SiC ceramic matrix composite

Energy Technology Data Exchange (ETDEWEB)

Saucedo-Mora, L. [Institute Eduardo Torroja for Construction Sciences-CSIC, Madrid (Spain); Department of Materials, University of Oxford (United Kingdom); Lowe, T. [Manchester X-ray Imaging Facility, The University of Manchester (United Kingdom); Zhao, S. [Department of Materials, University of Oxford (United Kingdom); Lee, P.D. [Research Complex at Harwell, Rutherford Appleton Laboratory (United Kingdom); Mummery, P.M. [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester (United Kingdom); Marrow, T.J., E-mail: james.marrow@materials.ox.ac.uk [Department of Materials, University of Oxford (United Kingdom)

2016-12-01

SiC-SiC ceramic matrix composites are candidate materials for fuel cladding in Generation IV nuclear fission reactors and as accident tolerant fuel clad in current generation plant. Experimental methods are needed that can detect and quantify the development of mechanical damage, to support modelling and qualification tests for these critical components. In situ observations of damage development have been obtained of tensile and C-ring mechanical test specimens of a braided nuclear grade SiC-SiC ceramic composite tube, using a combination of ex situ and in situ computed X-ray tomography observation and digital volume correlation analysis. The gradual development of damage by matrix cracking and also the influence of non-uniform loading are examined. - Highlights: • X-ray tomography with digital volume correlation measures 3D deformation in situ. • Cracking and damage in the microstructure can be detected using the strain field. • Fracture can initiate from the monolithic coating of a SiC-SiC ceramic composite.

In situ observation of mechanical damage within a SiC-SiC ceramic matrix composite

International Nuclear Information System (INIS)

Saucedo-Mora, L.; Lowe, T.; Zhao, S.; Lee, P.D.; Mummery, P.M.; Marrow, T.J.

2016-01-01

SiC-SiC ceramic matrix composites are candidate materials for fuel cladding in Generation IV nuclear fission reactors and as accident tolerant fuel clad in current generation plant. Experimental methods are needed that can detect and quantify the development of mechanical damage, to support modelling and qualification tests for these critical components. In situ observations of damage development have been obtained of tensile and C-ring mechanical test specimens of a braided nuclear grade SiC-SiC ceramic composite tube, using a combination of ex situ and in situ computed X-ray tomography observation and digital volume correlation analysis. The gradual development of damage by matrix cracking and also the influence of non-uniform loading are examined. - Highlights: • X-ray tomography with digital volume correlation measures 3D deformation in situ. • Cracking and damage in the microstructure can be detected using the strain field. • Fracture can initiate from the monolithic coating of a SiC-SiC ceramic composite.

Two phosphoenolpyruvate carboxykinases coexist in the Crassulacean Acid Metabolism plant Ananas comosus. Isolation and characterization of the smaller 65 kDa form.

Science.gov (United States)

Martín, Mariana; Rius, Sebastián Pablo; Podestá, Florencio Esteban

2011-06-01

Two phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.49) isoforms of 74 and 65 kDa were found to coexist in vivo in pineapple leaves, a constitutive Crassulacean Acid Metabolism plant. The 65 kDa form was not the result of proteolytic cleavage of the larger form since extraction methods reported to prevent PEPCK proteolysis in other plant tissues failed to yield a single immunoreactive PEPCK polypeptide in leaf extracts. In this work, the smaller form of 65 kDa was purified to homogeneity and physically and kinetically characterized and showed parameters compatible with a fully active enzyme. The specific activity was nearly twice higher for decarboxylation of oxaloacetate when compared to carboxylation of phosphoenolpyruvate. Kinetic parameters fell within the range of those estimated for other plant PEPCKs. Its activity was affected by several metabolites, as shown by inhibition by 3-phosphoglycerate, citrate, malate, fructose-1,6-bisphosphate, l-asparagine and activation of the decarboxylating activity by succinate. A break in the Arrhenius plot at about 30°C indicates that PEPCK structure is responsive to changes in temperature. The results indicate that pineapple leaves contain two PEPCK forms. The biochemical characterization of the smaller isoform performed in this work suggests that it could participate in both carbon and nitrogen metabolism in vivo by acting as a decarboxylase. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

In situ monitoring of stacking fault formation and its carrier lifetime mediation in p-type 4H-SiC

Energy Technology Data Exchange (ETDEWEB)

Chen, Bin, E-mail: chenbinmse@gmail.com; Chen, Jun; Yao, Yuanzhao; Sekiguchi, Takashi [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Matsuhata, Hirofumi; Okumura, Hajime [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

2014-07-28

Using the fine control of an electron beam (e-beam) in scanning electron microscopy with the capabilities of both electrical and optical imaging, the stacking fault (SF) formation together with its tuning of carrier lifetime was in situ monitored and investigated in p-type 4H-SiC homoepitaxial films. The SFs were formed through engineering basal plane dislocations with the energy supplied by the e-beam. The e-beam intensity required for the SF formation in the p-type films was ∼100 times higher than that in the n-type ones. The SFs reduced the minority-carrier lifetime in the p-type films, which was opposite to that observed in the n-type case. The reason for the peculiar SF behavior in the p-type 4H-SiC is discussed with the cathodoluminescence results.

In situ loading of Ag{sub 2}WO{sub 4} on ultrathin g-C{sub 3}N{sub 4} nanosheets with highly enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Li, Yunfeng; Jin, Renxi; Fang, Xu; Yang, Yang; Yang, Man; Liu, Xianchun [Jilin Provincial Key Laboratory of Advanced Energy Materials, Department of Chemistry, Northeast Normal University, Changchun 130024 (China); Xing, Yan, E-mail: xingy202@nenu.edu.cn [Jilin Provincial Key Laboratory of Advanced Energy Materials, Department of Chemistry, Northeast Normal University, Changchun 130024 (China); Song, Shuyan [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2016-08-05

Graphical abstract: Ultrathin g-C{sub 3}N{sub 4} nanosheets (g-C{sub 3}N{sub 4}−NS) with improved electron transport ability and large number of active sites are employed instead of bulk g-C{sub 3}N{sub 4} to prepare the Ag{sub 2}WO{sub 4}/g-C{sub 3}N{sub 4}−NS heterostructured photocatalysts, which exhibit remarkable photocatalytic activity for wastewater treatment. - Highlights: • Ag2WO4/g-C3N4-NS photocatalysts were obtained by a deposition-precipitation method. • Ag2WO4/g-C3N4-NS possess large surface areas and increased lifetime of charges. • Ag2WO4/g-C3N4-NS exhibit enhanced activity on degradation of RhB and MO. • The photocatalytic mechanism of the Ag2WO4/g-C3N4-NS system were investigated. - Abstract: The g-C{sub 3}N{sub 4} nanosheets (g-C{sub 3}N{sub 4}−NS) exhibit more excellent property than common bulk g-C{sub 3}N{sub 4} (g-C{sub 3}N{sub 4}-B) due to their large surface areas, improved electron transport ability and well dispersion in water. In this work, ultrathin g-C{sub 3}N{sub 4}−NS with a thickness of about 2.7 nm have been synthesized by a simple thermal exfoliation of bulk g-C{sub 3}N{sub 4}, and then Ag{sub 2}WO{sub 4} nanoparticles are in situ loaded on their surface to construct the Ag{sub 2}WO{sub 4}/g-C{sub 3}N{sub 4}−NS heterostructured photocatalysts. Due to their unique physicochemical properties, the as-prepared heterostructures possess a fast interfacial charge transfer and increased lifetime of photo-excited charge carriers, and exhibit much higher photocatalytic activity. Under visible light irradiation, the optimum photocatalytic activity of Ag{sub 2}WO{sub 4}/g-C{sub 3}N{sub 4}−NS composites is almost 53.6 and 26.5 times higher than that of pure g-C{sub 3}N{sub 4}-B and Ag{sub 2}WO{sub 4}/g-C{sub 3}N{sub 4}-B heterostructures towards the degradation of rhodamine B, respectively, and is almost 30.6 and 9.8 times higher towards the degradation of methyl orange, respectively. In addition, the natural sunlight

An ingenious strategy of preparing TiO2/g-C3N4 heterojunction photocatalyst: In situ growth of TiO2 nanocrystals on g-C3N4 nanosheets via impregnation-calcination method

Science.gov (United States)

Zhang, Guanghui; Zhang, Tianyong; Li, Bin; Jiang, Shuang; Zhang, Xia; Hai, Li; Chen, Xingwei; Wu, Wubin

2018-03-01

An ingenious method was employed to design and fabricate the TiO2/g-C3N4 heterojunction photocatalysts in this study. The thermal oxidation etching of g-C3N4 nanosheets and the in situ growth of TiO2 nanocrystal on the surface of g-C3N4 nanosheets were completed simultaneously by the calcination process. The g-C3N4 nanosheets played a crucial role in regulating and assembling the structures and morphologies of TiO2. Furthermore, the thickness and content of g-C3N4, and the crystallinity of TiO2 in TiO2/g-C3N4 composites could be regulated and controlled by the calcination temperature. Among the resultant TiO2/g-C3N4 samples, the TiO2/g-C3N4 sample with 41.6 wt% g-C3N4 exhibited the highest photocatalytic activity. It could degrade almost all MO molecules under visible light irradiation within 3 h. Moreover, it displayed higher visible light photocatalytic performance for degrading MO solution than pure g-C3N4 and D-TiO2. The synergistic effect between TiO2 and g-C3N4 makes significant contributions to the enhancement of the visible light photocatalytic activity. In addition, the favorable photocatalytic performance of TiO2/g-C3N4 nanocomposites is also attributed to the porous structures and uniform morphologies, and large surface area. Furthermore, the resultant TiO2/g-C3N4 exhibits excellent photocatalytic stability. Radical trapping experiments indicated that rad O2- and h+ were the main reactive species during the photodegradation process under visible light irradiation. Hopefully, the results can offer new design and strategy for preparing other g-C3N4-based nanocomposites for environmental and energy applications.

Microstructure of in-situ Synthesized (TiB+TiC)/Ti Composites Prepared by Hot-pressing

Institute of Scientific and Technical Information of China (English)

Zhenzhu ZHENG; Lin GENG; Honglin WANG; Weimin ZHOU; Hongyu XU

2003-01-01

In-situ 5 vol.pct TiB whiskers and TiC particulates reinforced Ti composites were fabricated by blending Ti powderand B4C particulates followed by reactive hot-pressing. The microstructure of the composites was investigated byusing differential scanning c

Daily rhythm of phosphoenolpyruvate carboxylase in Crassulacean acid metabolism plants : Immunological evidence for the absence of a rhythm in protein synthesis.

Science.gov (United States)

Brulfert, J; Vidal, J; Gadal, P; Queiroz, O

1982-11-01

Immunotitration of phosphoenolpyruvate carboxylase (EC 4.1.1.31) extracted from leaves of Kalanchoe blossfeldiana v. Poelln. cv. Tom Thumb. It was established that at different times of the day-night cycle the daily rhythm of enzyme capacity does not result from a rhythm in protein synthesis, but rather from changes in the specific activity of the enzyme.

In Situ Bioremediation of 1,4-Dioxane by Methane Oxidizing Bacteria in Coupled Anaerobic-Aerobic Zones

Science.gov (United States)

2016-02-11

FINAL REPORT In Situ Bioremediation of 1,4-Dioxane by Methane Oxidizing Bacteria in Coupled Anaerobic-Aerobic Zones SERDP Project ER-2306...volatile organic compound (CVOCs), ethene and ethane in groundwater at Raritan Arsenal Area 18C after in situ bioremediation . 4 List of...aquifers, the bioremediation approach most commonly used for chlorinated solvents. The ability of methanotrophs to biodegrade 1,4-dioxane was

In situ XANES studies of TiO{sub 2}/Fe{sub 3}O{sub 4}-C during photocatalytic degradation of trichloroethylene

Energy Technology Data Exchange (ETDEWEB)

Hsu, T.-F.; Hsiung, T.-L. [Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Wang, James [Department of Biomedical Engineering, University of Southern California, Los Angeles 90007 (United States); Huang, C.-H. [Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Paul Wang, H., E-mail: wanghp@mail.ncku.edu.t [Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Sustainable Environmental Research Center, National Cheng Kung University, Tainan 70101, Taiwan (China)

2010-07-21

Mainly anatase and Fe{sub 3}O{sub 4} in the magnetic photocatalysts (TiO{sub 2} on Fe{sub 3}O{sub 4}-C core-shell nanoparticles (TiO{sub 2}/Fe{sub 3}O{sub 4}-C)) are observed by X-ray powder diffraction (XRD) spectroscopy. The Ti K-edge least-square fitted XANES spectra of the TiO{sub 2}/Fe{sub 3}O{sub 4}-C photocatalyst indicate that the main titanium species are nanosize TiO{sub 2} (9 nm) (77%) and bulky TiO{sub 2} (23%). Speciation of titanium in the TiO{sub 2}/Fe{sub 3}O{sub 4}-C during photocatalytic degradation of 100 ppm of trichloroethylene (TCE) has also been studied by in situ X-ray absorption near-edge structural (XANES) spectroscopy. TiO{sub 2} is not perturbed during the course of photocatalysis. However, it is worth to note that during photocatalytic degradation of TCE, about 33% of FeO and 67% of Fe{sub 3}O{sub 4} are observed in the photocatalyst. It seems that the carbon layer on the TiO{sub 2}/Fe{sub 3}O{sub 4}-C photocatalysts can reduce the possibility for photoexcited electron-hole recombination as usually found on the relatively narrow bandgap of ferric oxide during photocatalysis.

In-situ TEM on (de)hydrogenation of Pd at 0.5–4.5 bar hydrogen pressure and 20–400°C

International Nuclear Information System (INIS)

Yokosawa, Tadahiro; Alan, Tuncay; Pandraud, Gregory; Dam, Bernard; Zandbergen, Henny

2012-01-01

We have developed a nanoreactor, sample holder and gas system for in-situ transmission electron microscopy (TEM) of hydrogen storage materials up to at least 4.5 bar. The MEMS-based nanoreactor has a microheater, two electron-transparent windows and a gas inlet and outlet. The holder contains various O-rings to have leak-tight connections with the nanoreactor. The system was tested with the (de)hydrogenation of Pd at pressures up to 4.5 bar. The Pd film consisted of islands being 15 nm thick and 50–500 nm wide. In electron diffraction mode we observed reproducibly a crystal lattice expansion and shrinkage owing to hydrogenation and dehydrogenation, respectively. In selected-area electron diffraction and bright/dark-field modes the (de)hydrogenation of individual Pd particles was followed. Some Pd islands are consistently hydrogenated faster than others. When thermally cycled, thermal hysteresis of about 10–16 °C between hydrogen absorption and desorption was observed for hydrogen pressures of 0.5–4.5 bar. Experiments at 0.8 bar and 3.2 bar showed that the (de)hydrogenation temperature is not affected by the electron beam. This result shows that this is a fast method to investigate hydrogen storage materials with information at the nanometer scale. -- Highlights: ► In-situ TEM experiments up to 4.5 bar. ► In-situ TEM on a hydrogen storage material at pressures used in practice. ► No electron beam effect on (de)hydrogenation. ► In-situ TEM allows for fast screening of hydrogen storage materials.

Preparation of 14-C-labelled 1,4-Dideoxy-1,4-imino-D-arabinitol: Cyanosilylation of Cyclic Imines using KCN in a One-Pot Synthesis

DEFF Research Database (Denmark)

Lundt, Inge; Malle, Birgitte Mølholm; Foged, Christian

1999-01-01

A new method for C-C bond formation was developed based on in situ cyanosilylation of cyclic Schiff bases using KCN, TMSCl, KI and ZnI2. This method was used to prepare the potent -glucosidase inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol 14-C labelled at C-5.Keywords: in situ cyanosilylation; 14-C...

Cytosolic phosphoenolpyruvate carboxykinase is a response gene involved in porcine adipocyte adaptation to heat stress.

Science.gov (United States)

Qu, Huan; Ajuwon, Kolapo M

2018-05-04

Heat stress (HS) leads to increased lipid storage and expression of cytosolic phosphoenolpyruvate carboxykinase (PCK1) in pig adipocytes. However, the importance of PCK1 activation and lipid storage in the adaptive response to HS is unknown. Therefore, in vitro experiments were conducted to investigate the effect of PCK1 inhibition with 3-mercaptopicolinic acid (3MPA) on lipid storage and adipocyte response during HS. In vitro culture of adipocytes under HS (41.0 °C) increased (P cultured adipocytes were less able to induce adaptive responses such as upregulation of HSP70 and triglycerides, and this exacerbated ER stress during HS. Thus, PCK1 may function to alleviate ER stress that occurs during HS.

Escherichia coli Phosphoenolpyruvate Dependent Phosphotransferase System. Copurification of HPr and α1-6 Glucan

NARCIS (Netherlands)

Dooijewaard, G.; Roossien, F.F.; Robillard, G.T.

1979-01-01

A rapid, high-yield procedure has been developed for the purification of HPr from the Escherichia coli phosphoenolpyruvate dependent phosphotransferase system. During this procedure, the protein copurifies with a 2500-dalton homopolysaccharide which we have identified as α1-6 glucan. The results of

Characterization of phosphoenolpyruvate carboxylase from mature maize seeds: Properties of phosphorylated and dephosphorylated forms

Czech Academy of Sciences Publication Activity Database

Černý, M.; Doubnerová, V.; Müller, Karel; Ryšlavá, H.

2010-01-01

Roč. 92, č. 10 (2010), s. 1362-1370 ISSN 0300-9084 R&D Projects: GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z50380511 Keywords : Phosphoenolpyruvate carboxylase * Phosphorylation * Seed Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.787, year: 2010

In situ high-resolution transmission electron microscopy synthesis observation of nanostructured carbon coated LiFePO 4

Science.gov (United States)

Trudeau, M. L.; Laul, D.; Veillette, R.; Serventi, A. M.; Mauger, A.; Julien, C. M.; Zaghib, K.

In situ high-resolution transmission electron microscopy (HRTEM) studies of the structural transformations that occur during the synthesis of carbon-coated LiFePO 4 (C-LiFePO 4) and heat treatment to elevated temperatures were conducted in two different electron microscopes. Both microscopes have sample holders that are capable of heating up to 1500 °C, with one working under high vacuum and the other capable of operating with the sample surrounded by a low gaseous environment. The C-LiFePO 4 samples were prepared using three different compositions of precursor materials with Fe(0), Fe(II) or Fe(III), a Li-containing salt and a polyethylene- block-poly(ethylene glycol)-50% ethylene oxide or lactose. The in situ TEM studies suggest that low-cost Fe(0) and a low-cost carbon-containing compound such as lactose are very attractive precursors for mass production of C-LiFePO 4, and that 700 °C is the optimum synthesis temperature. At temperatures higher than 800 °C, LiFePO 4 has a tendency to decompose. The same in situ measurements have been made on particles without carbon coat. The results show that the homogeneous deposit of the carbon deposit at 700 °C is the result of the annealing that cures the disorder of the surface layer of bare LiFePO 4. Electrochemical tests supported the conclusion that the C-LiFePO 4 derived from Fe(0) is the most attractive for mass production.

Conductive additive content balance in Li-ion battery cathodes: Commercial carbon blacks vs. in situ carbon from LiFePO{sub 4}/C composites

Energy Technology Data Exchange (ETDEWEB)

Palomares, Veronica; Goni, Aintzane; Muro, Izaskun Gil de; Rojo, Teofilo [Departamento de Quimica Inorganica, Universidad del Pais Vasco UPV/EHU, P.O. Box. 644, 48080, Bilbao (Spain); de Meatza, Iratxe; Bengoechea, Miguel [Energy Department, CIDETEC-IK4, P Miramon 196, Parque Tecnologico de San Sebastian, 20009, San Sebastian (Spain); Cantero, Igor [Departamento I+D+i Nuevas Tecnologias, CEGASA, Artapadura, 11, 01013 Vitoria-Gasteiz (Spain)

2010-11-15

Two samples of commercial conducting carbon black and the carbon generated in situ during LiFePO{sub 4}/C composite synthesis from citric acid are studied, with the aim of finding out whether carbon from the composite can fulfil the same function as carbon black in the electrode blend for a Li-ion battery. For this purpose, the carbon samples are analyzed by several techniques, such as X-ray diffraction, Raman spectroscopy, transmission electron microscopy, granulometry, BET specific area and conductivity measurements. Different cathode compositions and component proportions are tested for pellet and cast electrodes. Electrochemical results show that a moderate reduction of commercial carbon black content in both kinds of cathodes, by adding more LiFePO{sub 4}/C composite, enhanced the electrochemical behaviour by around 10%. In situ generated carbon can partially replace commercial conducting carbon black because its high specific surface probably enhances electrolyte penetration into the cathode, but it is always necessary to maintain a minimum amount of carbon black that provides better conductivity in order to obtain a good electrochemical response. (author)

Amino acid environment determines expression of carbamoylphosphate synthetase and phosphoenolpyruvate carboxykinase in embryonic rat hepatocytes

NARCIS (Netherlands)

Lamers, W. H.; van Roon, M.; Mooren, P. G.; de Graaf, A.; Charles, R.

1985-01-01

A completely defined medium (EHM-1), which reflects the amino acid composition of fetal rat serum and contains albumin as the sole proteinaceous compound, allows the accumulation of carbamoylphosphate synthetase and phosphoenolpyruvate carboxykinase in the presence of dexamethasone, dibutyryl cyclic

Phosphoenolpyruvate carboxykinase and gluconeogenesis in grape pericarp.

Science.gov (United States)

Walker, Robert P; Battistelli, Alberto; Moscatello, Stefano; Técsi, László; Leegood, Richard C; Famiani, Franco

2015-12-01

Glycolysis from sugars is necessary at all stages of development of grape pericarp, and this raises the question as to why gluconeogenesis from malate occurs. Phosphoenolpyruvate carboxykinase (PEPCK) is required for gluconeogenesis in grape pericarp. In this study we determined the abundance of PEPCK protein and activity in different parts of grape pericarp during its development. Both PEPCK protein and activity were present throughout development, however, in both the skin and the flesh their abundance increased greatly at the start of ripening. This coincided with the onset of the decrease in the malate content of the berry. The location of PEPCK in the pericarp at different stages of development was determined using both immunohistochemistry and dissection. We provide a possible explanation for the occurrence of gluconeogenesis in grape pericarp. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

In situ growing Bi_2MoO_6 on g-C_3N_4 nanosheets with enhanced photocatalytic hydrogen evolution and disinfection of bacteria under visible light irradiation

International Nuclear Information System (INIS)

Li, Juan; Yin, Yunchao; Liu, Enzhou; Ma, Yongning; Wan, Jun; Fan, Jun; Hu, Xiaoyun

2017-01-01

Graphical abstract: TEM image and schematic diagram of photocatalytic mechanism of Bi_2MoO_6/g-C_3N_4 composite. - Highlights: • BM/CNNs heterojunctions were obtained by an in situ solvothermal method. • 2D CNNs are superior to CN as photocatalysts and supporting materials. • The photocatalytic hydrogen evolution of BM/CNNs has been first studied. • The photocatalytic disinfection of bacteria by BM/CNNs has been first studied. • The photocatalytic mechanism of BM/CNNs heterojunction was described. - Abstract: Bi_2MoO_6/g-C_3N_4 heterojunctions were fabricated by an in situ solvothermal method using g-C_3N_4 nanosheets. The photocatalytic activities of as-prepared samples were evaluated by hydrogen evolution from water splitting and disinfection of bacteria under visible light irradiation. The results indicate that exfoliating bulk g-C_3N_4 to g-C_3N_4 nanosheets greatly enlarges the specific surface area and shortens the diffusion distance for photogenerated charges, which could not only promote the photocatalytic performance but also benefit the sufficient interaction with Bi_2MoO_6. Furthermore, intimate contact of Bi_2MoO_6 (BM) and g-C_3N_4 nanosheets (CNNs) in the BM/CNNs composites facilitates the transfer and separation of photogenetrated electron-hole pairs. 20%-BM/CNNs heterojunction exhibits the optimal photocatalytic hydrogen evolution as well as photocatalytic disinfection of bacteria. Furthermore, h"+ was demonstrated as the dominant reactive species which could make the bacteria cells inactivated in the photocatalytic disinfection process. This study extends new chance of g-C_3N_4-based photocatalysts to the growing demand of clean new energy and drinking water.

Effect of phosphorus deficiency in photoassimilated /sup 14/C metabolism in sunflower

Energy Technology Data Exchange (ETDEWEB)

Stanev, V.; Angelov, M.; Popov, G. (Bylgarska Akademiya na Naukite, Sofia. Inst. po Fiziologiya na Rasteniyata)

1981-01-01

Phosphorus deficiency in photoassimilated /sup 14/C metabolism in plants is a controversial problem. The effect of the total removal of phosphorus from the nutrient medium is investigated. The experiments are carried out with sunflower of the Peredovic variety, grown as hydroponics with Hellriegel's nutrient solution. The investigations are performed after a 19-day removal of phosphorus from the nutrient medium. An enhanced labelling of aspartate and malate, products of the carboxylation of phosphoenolpyruvate is observed, which indicates that the flow of the newly assimilated /sup 14/C is directed to a higher degree towards the reaction of carboxylation of phosphoenolpyruvate and its compounds (malate and aspartate). Possibly on disturbing the initial CO/sub 2/ assimilation by ribulosediphosphate, phosphorus deficiency induces a stronger CO/sub 2/ fixation through the C/sub 4/ pathway in order to compensate to a certain extent the strongly decreased supply of carbon skeletons for metabolism in plants.

C4.4A as a biomarker in pulmonary adenocarcinoma and squamous cell carcinoma

DEFF Research Database (Denmark)

Jacobsen, Benedikte; Kriegbaum, Mette Camilla; Santoni-Rugiu, Eric

2014-01-01

to invasive carcinomas of the lung, i.e., in bronchial hyperplasia/metaplasia and atypical adenomatous hyperplasia. In the stages leading to pulmonary squamous cell carcinoma, expression is sustained in dysplasia, carcinoma in situ and invasive carcinomas, and this pertains to the normal presence of C4.4A...... in squamous epithelium. In pulmonary adenocarcinomas, a fraction of cases is positive for C4.4A, which is surprising, given the origin of these carcinomas from mucin-producing and not squamous epithelium. Interestingly, this correlates with a highly compromised patient survival and a predominant solid tumor...

A Common histone modification code on C4 genes in maize and its conservation in Sorghum and Setaria italica.

Science.gov (United States)

Heimann, Louisa; Horst, Ina; Perduns, Renke; Dreesen, Björn; Offermann, Sascha; Peterhansel, Christoph

2013-05-01

C4 photosynthesis evolved more than 60 times independently in different plant lineages. Each time, multiple genes were recruited into C4 metabolism. The corresponding promoters acquired new regulatory features such as high expression, light induction, or cell type-specific expression in mesophyll or bundle sheath cells. We have previously shown that histone modifications contribute to the regulation of the model C4 phosphoenolpyruvate carboxylase (C4-Pepc) promoter in maize (Zea mays). We here tested the light- and cell type-specific responses of three selected histone acetylations and two histone methylations on five additional C4 genes (C4-Ca, C4-Ppdk, C4-Me, C4-Pepck, and C4-RbcS2) in maize. Histone acetylation and nucleosome occupancy assays indicated extended promoter regions with regulatory upstream regions more than 1,000 bp from the transcription initiation site for most of these genes. Despite any detectable homology of the promoters on the primary sequence level, histone modification patterns were highly coregulated. Specifically, H3K9ac was regulated by illumination, whereas H3K4me3 was regulated in a cell type-specific manner. We further compared histone modifications on the C4-Pepc and C4-Me genes from maize and the homologous genes from sorghum (Sorghum bicolor) and Setaria italica. Whereas sorghum and maize share a common C4 origin, C4 metabolism evolved independently in S. italica. The distribution of histone modifications over the promoters differed between the species, but differential regulation of light-induced histone acetylation and cell type-specific histone methylation were evident in all three species. We propose that a preexisting histone code was recruited into C4 promoter control during the evolution of C4 metabolism.

Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation.

Science.gov (United States)

Kromdijk, Johannes; Ubierna, Nerea; Cousins, Asaph B; Griffiths, Howard

2014-07-01

Crop species with the C4 photosynthetic pathway are generally characterized by high productivity, especially in environmental conditions favouring photorespiration. In comparison with the ancestral C3 pathway, the biochemical and anatomical modifications of the C4 pathway allow spatial separation of primary carbon acquisition in mesophyll cells and subsequent assimilation in bundle-sheath cells. The CO2-concentrating C4 cycle has to operate in close coordination with CO2 reduction via the Calvin-Benson-Bassham (CBB) cycle in order to keep the C4 pathway energetically efficient. The gradient in CO2 concentration between bundle-sheath and mesophyll cells facilitates diffusive leakage of CO2. This rate of bundle-sheath CO2 leakage relative to the rate of phosphoenolpyruvate carboxylation (termed leakiness) has been used to probe the balance between C4 carbon acquisition and subsequent reduction as a result of environmental perturbations. When doing so, the correct choice of equations to derive leakiness from stable carbon isotope discrimination (Δ(13)C) during gas exchange is critical to avoid biased results. Leakiness responses to photon flux density, either short-term (during measurements) or long-term (during growth and development), can have important implications for C4 performance in understorey light conditions. However, recent reports show leakiness to be subject to considerable acclimation. Additionally, the recent discovery of two decarboxylating C4 cycles operating in parallel in Zea mays suggests that flexibility in the transported C4 acid and associated decarboxylase could also aid in maintaining C4/CBB balance in a changing environment. In this paper, we review improvements in methodology to estimate leakiness, synthesize reports on bundle-sheath leakiness, discuss different interpretations, and highlight areas where future research is necessary. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology

Pyramiding expression of maize genes encoding phosphoenolpyruvate carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) synergistically improve the photosynthetic characteristics of transgenic wheat.

Science.gov (United States)

Zhang, HuiFang; Xu, WeiGang; Wang, HuiWei; Hu, Lin; Li, Yan; Qi, XueLi; Zhang, Lei; Li, ChunXin; Hua, Xia

2014-09-01

Using particle bombardment transformation, we introduced maize pepc cDNA encoding phosphoenolpyruvate carboxylase (PEPC) and ppdk cDNA encoding pyruvate orthophosphate dikinase (PPDK) into the C3 crop wheat to generate transgenic wheat lines carrying cDNA of pepc (PC lines), ppdk (PK lines) or both (PKC lines). The integration, transcription, and expression of the foreign genes were confirmed by Southern blot, Real-time quantitative reverse transcription PCR (Q-RT-PCR), and Western blot analysis. Q-RT-PCR results indicated that the average relative expression levels of pepc and ppdk in the PKC lines reached 10 and 4.6, respectively, compared to their expressions in untransformed plants (set to 1). The enzyme activities of PEPC and PPDK in the PKC lines were 4.3- and 2.1-fold higher, respectively, than in the untransformed control. The maximum daily net photosynthetic rates of the PKC, PC, and PK lines were enhanced by 26.4, 13.3, and 4.5%, respectively, whereas the diurnal accumulations of photosynthesis were 21.3, 13.9, and 6.9%, respectively, higher than in the control. The Fv/Fm of the transgenic plants decreased less than in the control under high temperature and high light conditions (2 weeks after anthesis), suggesting that the transgenic wheat transports more absorbed light energy into a photochemical reaction. The exogenous maize C4-specific pepc gene was more effective than ppdk at improving the photosynthetic performance and yield characteristics of transgenic wheat, while the two genes showed a synergistic effect when they were transformed into the same genetic background, because the PKC lines exhibited improved photosynthetic and physiological traits.

Identification and functional verification of archaeal-type phosphoenolpyruvate carboxylase, a missing link in archaeal central carbohydrate metabolism.

NARCIS (Netherlands)

Ettema, T.J.G.; Makarova, K.S.; Jellema, G.L.; Gierman, H.J.; Koonin, E.V.; Huynen, M.A.; Vos, W.M. de; Oost, J. van der

2004-01-01

Despite the fact that phosphoenolpyruvate carboxylase (PEPC) activity has been measured and in some cases even purified from some Archaea, the gene responsible for this activity has not been elucidated. Using sensitive sequence comparison methods, we detected a highly conserved, uncharacterized

Identification and functional verification of Archaeal-type phosphoenolpyruvate carboxylase, a missing link in Archaeal central carbohydrate metabolism

NARCIS (Netherlands)

Ettema, T.J.G.; Makarova, K.S.; Jellema, G.L.; Gierman, H.J.; Koonin, E.V.; Huynen, M.A.; Vos, de W.M.; Oost, van der J.

2004-01-01

Despite the fact that phosphoenolpyruvate carboxylase (PEPC) activity has been measured and in some cases even purified from some Archaea, the gene responsible for this activity has not been elucidated. Using sensitive sequence comparison methods, we detected a highly conserved, uncharacterized

A STUDY ON MICROSTRUCTURE CHARACTERISTICS OF IN SITU FORMED TiC REINFORCED COMPOSITE COATINGS

OpenAIRE

PENG LIU; WEI GUO; HUI LUO

2012-01-01

In situ synthesized TiC reinforced composite coating was fabricated by laser cladding of Al-Ni-Cr-C powders on titanium alloys, which can greatly improve the surface performance of the substrate. In this study, the Al-Ni-Cr-C laser-cladded composite coatings have been researched by means of X-ray diffraction, scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). There was a metallurgical combination between the Al-Ni-Cr-C laser-cladded coating and the Ti-6Al-4V substrat...

Coherent Structure in Solar Wind C$^{6+}$/C$^{4+}$ Ionic Composition Data During the Quiet-Sun Conditions of 2008

OpenAIRE

Edmondson, J. K.; Lynch, B. J.; Lepri, S. T.; Zurbuchen, T. H.

2013-01-01

This analysis offers evidence of characteristic scale sizes in solar wind charge state data measured in-situ for thirteen quiet-sun Carrington rotations in 2008. Using a previously established novel methodology, we analyze the wavelet power spectrum of the charge state ratio C$^{6+}$/C$^{4+}$ measured in-situ by ACE/SWICS for 2-hour and 12-minute cadence. We construct a statistical significance level in the wavelet power spectrum to quantify the interference effects arising from filling missi...

Room-temperature in situ fabrication of Bi2O3/g-C3N4 direct Z-scheme photocatalyst with enhanced photocatalytic activity

Science.gov (United States)

He, Rongan; Zhou, Jiaqian; Fu, Huiqing; Zhang, Shiying; Jiang, Chuanjia

2018-02-01

Constructing direct Z-scheme heterojunction is an effective approach to separating photogenerated charge carriers and improving the activity of semiconductor photocatalysts. Herein, a composite of bismuth(III) oxide (Bi2O3) and graphitic carbon nitride (g-C3N4) was in situ fabricated at room temperature by photoreductive deposition of Bi3+ and subsequent air-oxidation of the resultant metallic Bi. Quantum-sized ω-Bi2O3 nanoparticles approximately 6 nm in diameter were uniformly distributed on the surface of mesoporous g-C3N4. The as-prepared Bi2O3/g-C3N4 composite exhibited higher photocatalytic activity than pure Bi2O3 and g-C3N4 for photocatalytic degradation of phenol under visible light. Reactive species trapping experiments revealed that superoxide radicals and photogenerated holes played important roles in the photocatalytic degradation of phenol. The enhanced photocatalytic activity, identification of reactive species and higher rate of charge carrier recombination (as indicated by stronger photoluminescence intensity) collectively suggest that the charge migration within the Bi2O3/g-C3N4 composite followed a Z-scheme mechanism. Photogenerated electrons on the conduction band of Bi2O3 migrate to the valence band of g-C3N4 and combine with photogenerated holes therein. At the cost of these less reactive charge carriers, the Z-scheme heterojunction enables efficient charge separation, while preserving the photogenerated electrons and holes with stronger redox abilities, which is beneficial for enhanced photocatalytic activity.

a Study on Microstructure Characteristics of IN SITU Formed TiC Reinforced Composite Coatings

Science.gov (United States)

Liu, Peng; Guo, Wei; Luo, Hui

2012-04-01

In situ synthesized TiC reinforced composite coating was fabricated by laser cladding of Al-Ni-Cr-C powders on titanium alloys, which can greatly improve the surface performance of the substrate. In this study, the Al-Ni-Cr-C laser-cladded composite coatings have been researched by means of X-ray diffraction, scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). There was a metallurgical combination between the Al-Ni-Cr-C laser-cladded coating and the Ti-6Al-4V substrate, and the micro-hardness of the Al-Ni-Cr-C laser-cladded coating was in the range of 1200-1450 HV0.2, which was 3-4 times higher than that of Ti-6Al-4V substrate. Furthermore, the reinforcement of theAl-Ni-Cr-C laser-cladded coating were mainly contributed to the action of the TiC, Ti3Al, Cr7C3, Al8Cr5 phases and the solution strengthening.

Phenobarbital reduces blood glucose and gluconeogenesis through down-regulation of phosphoenolpyruvate carboxykinase (GTP) gene expression in rats.

Science.gov (United States)

Oda, Hiroaki; Okuda, Yuji; Yoshida, Yukiko; Kimura, Noriko; Kakinuma, Atsushi

2015-10-23

The regulatory mechanism of phosphoenolpyruvate carboykinase (GTP) (EC 4.1.1.32) (PEPCK) gene expression and gluconeogenesis by phenobarbital (PB), which is known to induce drug-metabolizing enzymes, was investigated. Higher level of PEPCK mRNA was observed in spherical rat primary hepatocytes on EHS-gel than monolayer hepatocytes on TIC (type I collagen). We found that PB directly suppressed PEPCK gene expression in spherical hepatocytes on EHS-gel, but not in those on TIC. PB strongly suppressed cAMP-dependent induction of PEPCK gene expression. Tyrosine aminotransferase (TAT), another gluconeogenic enzyme, was induced by cAMP, but not suppressed by PB. Chronic administration of PB reduced hepatic PEPCK mRNA in streptozotocin-induced diabetic and nondiabetic rats, and PB reduced blood glucose level in diabetic rats. Increased TAT mRNA in diabetic rats was not suppressed by PB. These results indicated that PB-dependent reduction is specific to PEPCK. From pyrvate challenge test, PB suppressed the increased gluconeogenesis in diabetic rats. PEPCK gene promoter activity was suppressed by PB in HepG2 cells. In conclusion, we found that spherical hepatocytes cultured on EHS-gel are capable to respond to PB to suppress PEPCK gene expression. Moreover, our results indicate that hypoglycemic action of PB result from transcriptional repression of PEPCK gene and subsequent suppression of gluconeogenesis. Copyright © 2015. Published by Elsevier Inc.

Progress in automated extraction and purification of in situ {sup 14}C from quartz: Results from the Purdue in situ {sup 14}C laboratory

Energy Technology Data Exchange (ETDEWEB)

Lifton, Nathaniel, E-mail: nlifton@purdue.edu [Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907 (United States); Department of Physics and Astronomy and Purdue Rare Isotope Measurement Laboratory (PRIME Lab), Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Goehring, Brent, E-mail: bgoehrin@tulane.edu [Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907 (United States); Wilson, Jim, E-mail: jim.wilson@aeonlaboratories.com [Aeon Laboratories, LLC, 5835 North Genematas Drive, Tucson, AZ 85704 (United States); Kubley, Thomas [Department of Physics and Astronomy and Purdue Rare Isotope Measurement Laboratory (PRIME Lab), Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Caffee, Marc [Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907 (United States); Department of Physics and Astronomy and Purdue Rare Isotope Measurement Laboratory (PRIME Lab), Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

2015-10-15

Current extraction methods for in situ {sup 14}C from quartz [e.g., Lifton et al., (2001), Pigati et al., (2010), Hippe et al., (2013)] are time-consuming and repetitive, making them an attractive target for automation. We report on the status of in situ {sup 14}C extraction and purification systems originally automated at the University of Arizona that have now been reconstructed and upgraded at the Purdue Rare Isotope Measurement Laboratory (PRIME Lab). The Purdue in situ {sup 14}C laboratory builds on the flow-through extraction system design of Pigati et al. (2010), automating most of the procedure by retrofitting existing valves with external servo-controlled actuators, regulating the pressure of research purity O{sub 2} inside the furnace tube via a PID-based pressure controller in concert with an inlet mass flow controller, and installing an automated liquid N{sub 2} distribution system, all driven by LabView® software. A separate system for cryogenic CO{sub 2} purification, dilution, and splitting is also fully automated, ensuring a highly repeatable process regardless of the operator. We present results from procedural blanks and an intercomparison material (CRONUS-A), as well as results of experiments to increase the amount of material used in extraction, from the standard 5 g to 10 g or above. Results thus far are quite promising with procedural blanks comparable to previous work and significant improvements in reproducibility for CRONUS-A measurements. The latter analyses also demonstrate the feasibility of quantitative extraction of in situ {sup 14}C from sample masses up to 10 g. Our lab is now analyzing unknowns routinely, but lowering overall blank levels is the focus of ongoing research.

Expression of C4.4A in precursor lesions of pulmonary adenocarcinoma and squamous cell carcinoma

DEFF Research Database (Denmark)

Jacobsen, Benedikte; Santoni-Rugiu, Eric; Illemann, Martin

2012-01-01

in precursor lesions of lung squamous cell carcinoma and adenocarcinoma was investigated by stainings with a specific anti-C4.4A antibody. In the transformation from normal bronchial epithelium to squamous cell carcinoma, C4.4A was weakly expressed in basal cell hyperplasia but dramatically increased...... in squamous metaplasia. This was confined to the cell membrane and sustained in dysplasia, carcinoma in situ, and the invasive carcinoma. The induction of C4.4A already at the stage of hyperplasia could indicate that it is a marker of very early squamous differentiation, which aligns well with our earlier...... finding that C4.4A expression levels do not provide prognostic information on the survival of squamous cell carcinoma patients. In the progression from normal alveolar epithelium to peripheral adenocarcinoma, we observed an unexpected, distinct cytoplasmic staining for C4.4A in a fraction of atypical...

Preparation and mechanical properties of in situ TiC{sub x}–Ni (Si, Ti) alloy composites

Energy Technology Data Exchange (ETDEWEB)

Wang, Wenjuan [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhai, Hongxiang, E-mail: hxzhai@sina.com [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Chen, Lin; Huang, Zhenying [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Bei, Guoping; Baumgärtner, Christoph; Greil, Peter [Department of Materials Science (Glass and Ceramics), University of Erlangen-Nuernberg, Martensstr. 5, 91058 Erlangen (Germany)

2014-10-20

Novel in situ TiC{sub x} reinforced Ni (Si, Ti) alloy composites with superior mechanical properties were prepared at 1250 °C for 30 min by pressureless sintering Ti{sub 3}SiC{sub 2} (10 and 20 vol%) and Ni as precursors. The Ti{sub 3}SiC{sub 2} particles decomposed into substoichiometric TiC{sub x} phase, while the additional Si and partial Ti atoms derived from Ti{sub 3}SiC{sub 2} diffused into Ni matrix to form Ni (Si, Ti) alloy. The in situ formed TiC{sub x} phases are mainly dispersed on the grain boundaries of the Ni (Si, Ti) alloying, forming a strong skeleton and refining the microstructures of the metal matrix. The hardness, the yield stress σ{sub 0.2%} and ultimate compressive strength of 20.6 vol%TiC{sub x}–Ni(Si, Ti) composite can reach 2.15±0.04 GPa, 466.8±55.8 MPa and 733.3±78.4 MPa, respectively. The enhanced mechanical properties of TiC{sub x}–Ni(Si, Ti) composites are due to the in situ formation of TiC{sub x} skeleton, the refined microstructures of Ni (Si, Ti) alloys and solid solution effects as well as good wettability between TiC{sub x} and Ni (Si, Ti) matrix.

Valence band photoemission from in-situ grown GaAs(100)-c(4 x 4)

Czech Academy of Sciences Publication Activity Database

Jiříček, Petr; Cukr, Miroslav; Bartoš, Igor; Adell, M.; Strasser, T.; Schattke, W.

2006-01-01

Roč. 56, č. 1 (2006), s. 21-26 ISSN 0011-4626. [Symposium on Surface Physics /10./. Praha, 11.07.2005-15.07.2005] R&D Projects: GA ČR(CZ) GA202/04/0994 Institutional research plan: CEZ:AV0Z10100521 Keywords : GaAs(100)-c(4X4) * surface states * band structure * structure plot Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.568, year: 2006

Mechanism for microwave heating of 1-(4'-cyanophenyl)-4-propylcyclohexane characterized by in situ microwave irradiation NMR spectroscopy.

Science.gov (United States)

Tasei, Yugo; Yamakami, Takuya; Kawamura, Izuru; Fujito, Teruaki; Ushida, Kiminori; Sato, Motoyasu; Naito, Akira

2015-05-01

Microwave heating is widely used to accelerate organic reactions and enhance the activity of enzymes. However, the detailed molecular mechanism for the effect of microwave on chemical reactions is not yet fully understood. To investigate the effects of microwave heating on organic compounds, we have developed an in situ microwave irradiation NMR spectroscopy. (1)H NMR spectra of 1-(4'-cyanophenyl)-4-propylcyclohexane (PCH3) in the liquid crystalline and isotropic phases were observed under microwave irradiation. When the temperature was regulated at slightly higher than the phase transition temperature (Tc=45 °C) under a gas flow temperature control system, liquid crystalline phase mostly changed to the isotropic phase. Under microwave irradiation and with the gas flow temperature maintained at 20 °C, which is 25 °C below the Tc, the isotropic phase appeared stationary as an approximately 2% fraction in the liquid crystalline phase. The temperature of the liquid crystalline state was estimated to be 38 °C according to the line width, which is at least 7 °C lower than the Tc. The temperature of this isotropic phase should be higher than 45 °C, which is considered to be a non-equilibrium local heating state induced by microwave irradiation. Microwaves at a power of 195 W were irradiated to the isotropic phase of PCH3 at 50 °C and after 2 min, the temperature reached 220 °C. The temperature of PCH3 under microwave irradiation was estimated by measurement of the chemical shift changes of individual protons in the molecule. These results demonstrate that microwave heating generates very high temperature within a short time using an in situ microwave irradiation NMR spectrometer. Copyright © 2015 Elsevier Inc. All rights reserved.

A Common Histone Modification Code on C4 Genes in Maize and Its Conservation in Sorghum and Setaria italica1[W][OA

Science.gov (United States)

Heimann, Louisa; Horst, Ina; Perduns, Renke; Dreesen, Björn; Offermann, Sascha; Peterhansel, Christoph

2013-01-01

C4 photosynthesis evolved more than 60 times independently in different plant lineages. Each time, multiple genes were recruited into C4 metabolism. The corresponding promoters acquired new regulatory features such as high expression, light induction, or cell type-specific expression in mesophyll or bundle sheath cells. We have previously shown that histone modifications contribute to the regulation of the model C4 phosphoenolpyruvate carboxylase (C4-Pepc) promoter in maize (Zea mays). We here tested the light- and cell type-specific responses of three selected histone acetylations and two histone methylations on five additional C4 genes (C4-Ca, C4-Ppdk, C4-Me, C4-Pepck, and C4-RbcS2) in maize. Histone acetylation and nucleosome occupancy assays indicated extended promoter regions with regulatory upstream regions more than 1,000 bp from the transcription initiation site for most of these genes. Despite any detectable homology of the promoters on the primary sequence level, histone modification patterns were highly coregulated. Specifically, H3K9ac was regulated by illumination, whereas H3K4me3 was regulated in a cell type-specific manner. We further compared histone modifications on the C4-Pepc and C4-Me genes from maize and the homologous genes from sorghum (Sorghum bicolor) and Setaria italica. Whereas sorghum and maize share a common C4 origin, C4 metabolism evolved independently in S. italica. The distribution of histone modifications over the promoters differed between the species, but differential regulation of light-induced histone acetylation and cell type-specific histone methylation were evident in all three species. We propose that a preexisting histone code was recruited into C4 promoter control during the evolution of C4 metabolism. PMID:23564230

New metal-organic frameworks of [M(C6H5O7)(C6H6O7)(C6H7O7)(H2O)] . H2O (M=La, Ce) and [Ce2(C2O4)(C6H6O7)2] . 4H2O

International Nuclear Information System (INIS)

Weng Shengfeng; Wang, Yun-Hsin; Lee, Chi-Shen

2012-01-01

Two novel materials, [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2), with a metal-organic framework (MOF) were prepared with hydrothermal reactions and characterized with photoluminescence, magnetic susceptibility, thermogravimetric analysis and X-ray powder diffraction in situ. The crystal structures were determined by single-crystal X-ray diffraction. Compound 1 crystallized in triclinic space group P1-bar (No. 2); compound 2 crystallized in monoclinic space group P2 1 /c (No. 14). The structure of 1 is built from a 1D MOF, composed of deprotonated citric ligands of three kinds. Compound 2 contains a 2D MOF structure consisting of citrate and oxalate ligands; the oxalate ligand arose from the decomposition in situ of citric acid in the presence of Cu II ions. Photoluminescence spectra of compounds 1b and 2 revealed transitions between the 5d 1 excited state and two levels of the 4f 1 ground state ( 2 F 5/2 and 2 F 7/2 ). Compounds 1b and 2 containing Ce III ion exhibit a paramagnetic property with weak antiferromagnetic interactions between the two adjacent magnetic centers. - Graphical Abstract: [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2)—with 1D and 2D structures were synthesized and characterized. Highlights: ► Two MOF – [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2) – with 1D and 2D structures. ► The adjacent chains of the 1D framework were correlated with each other through an oxalate ligand to form a 2D layer structure. ► The source of the oxalate ligand was the decomposition in situ of citric acid oxidized in the presence of Cu II ions.

In situ growing Bi{sub 2}MoO{sub 6} on g-C{sub 3}N{sub 4} nanosheets with enhanced photocatalytic hydrogen evolution and disinfection of bacteria under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Li, Juan [School of Chemical Engineering, Northwest University, Xi’an, 710069 (China); School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang, 471023 (China); Yin, Yunchao; Liu, Enzhou; Ma, Yongning; Wan, Jun [School of Chemical Engineering, Northwest University, Xi’an, 710069 (China); Fan, Jun, E-mail: fanjun@nwu.edu.cn [School of Chemical Engineering, Northwest University, Xi’an, 710069 (China); Hu, Xiaoyun, E-mail: hxy3275@nwu.edu.cn [School of Physics, Northwest University, Xi’an, 710069 (China)

2017-01-05

Graphical abstract: TEM image and schematic diagram of photocatalytic mechanism of Bi{sub 2}MoO{sub 6}/g-C{sub 3}N{sub 4} composite. - Highlights: • BM/CNNs heterojunctions were obtained by an in situ solvothermal method. • 2D CNNs are superior to CN as photocatalysts and supporting materials. • The photocatalytic hydrogen evolution of BM/CNNs has been first studied. • The photocatalytic disinfection of bacteria by BM/CNNs has been first studied. • The photocatalytic mechanism of BM/CNNs heterojunction was described. - Abstract: Bi{sub 2}MoO{sub 6}/g-C{sub 3}N{sub 4} heterojunctions were fabricated by an in situ solvothermal method using g-C{sub 3}N{sub 4} nanosheets. The photocatalytic activities of as-prepared samples were evaluated by hydrogen evolution from water splitting and disinfection of bacteria under visible light irradiation. The results indicate that exfoliating bulk g-C{sub 3}N{sub 4} to g-C{sub 3}N{sub 4} nanosheets greatly enlarges the specific surface area and shortens the diffusion distance for photogenerated charges, which could not only promote the photocatalytic performance but also benefit the sufficient interaction with Bi{sub 2}MoO{sub 6}. Furthermore, intimate contact of Bi{sub 2}MoO{sub 6} (BM) and g-C{sub 3}N{sub 4} nanosheets (CNNs) in the BM/CNNs composites facilitates the transfer and separation of photogenetrated electron-hole pairs. 20%-BM/CNNs heterojunction exhibits the optimal photocatalytic hydrogen evolution as well as photocatalytic disinfection of bacteria. Furthermore, h{sup +} was demonstrated as the dominant reactive species which could make the bacteria cells inactivated in the photocatalytic disinfection process. This study extends new chance of g-C{sub 3}N{sub 4}-based photocatalysts to the growing demand of clean new energy and drinking water.

Application of a Novel and Automated Branched DNA in Situ Hybridization Method for the Rapid and Sensitive Localization of mRNA Molecules in Plant Tissues

Directory of Open Access Journals (Sweden)

Andrew J. Bowling

2014-04-01

Full Text Available Premise of the study: A novel branched DNA detection technology, RNAscope in situ hybridization (ISH, originally developed for use on human clinical and animal tissues, was adapted for use in plant tissue in an attempt to overcome some of the limitations associated with traditional ISH assays. Methods and Results: Zea mays leaf tissue was formaldehyde fixed and paraffin embedded (FFPE and then probed with the RNAscope ISH assay for two endogenous genes, phosphoenolpyruvate carboxylase (PEPC and phosphoenolpyruvate carboxykinase (PEPCK. Results from both manual and automated methods showed tissue- and cell-specific mRNA localization patterns expected from these well-studied genes. Conclusions: RNAscope ISH is a sensitive method that generates high-quality, easily interpretable results from FFPE plant tissues. Automation of the RNAscope method on the Ventana Discovery Ultra platform allows significant advantages for repeatability, reduction in variability, and flexibility of workflow processes.

Development and characterization of La/B{sub 4}C multilayer systems as X-ray mirrors in the energy range 100-200 eV; Entwicklung und Charakterisierung von La/B{sub 4}C-Multischichtsystemen als Roentgenspiegel im Energiebereich 100-200 eV

Energy Technology Data Exchange (ETDEWEB)

Hendel, Stefan

2009-01-15

The main topics of this thesis are the development and characterization of La/B{sub 4}C multilayer systems. For this these materials were evaluated and characterized for the applied electron-beam evaporation. For the monitoring of the evaporation process two separate in-situ layer thicknesses were available. For periodic multilayer systems the X-ray reflectometry used for Mo/Si multilayers was accepted. Because of the change from Mo/Si on La/B{sub 4}C the driving of the evaporation process had to be material-conditionedly further developed and optimized. For the fabrication of aperiodic La/B{sub 4}C multilayer systems additionally an in-situ ellipsometer was taken into operation. Furthermore a decreasement of the interface roughnesses and by this following increasement of the reflectivities of La/B{sub 4}C multilayers by polishing of the single layers with accelerated ions during the fabrication shall be studied. The fabricated multilayers are characterized and evaluated concerning roughnesses, reflectivities, ans spectral band width. [German] Im Mittelpunkt dieser Arbeit stehen die Entwicklung und Charakterisierung von La/B{sub 4}C-Multischichtsystemen. Dazu wurden diese Materialien fuer die verwendete Elektronenstrahlverdampfung evaluiert und charakterisiert. Fuer die Ueberwachung des Aufdampfprozesses standen zwei separate In-situ Schichtdickenkontrollen zur Verfuegung. Fuer periodische Multischichtsysteme wurde die fuer Mo/Si-Multischichten genutzte Roentgenreflektometrie uebernommen. Aufgrund des Wechsels von Mo/Si auf La/B{sub 4}C musste materialbedingt die Steuerung des Verdampfungsprozesses weiterentwickelt und optimiert werden. Fuer die Herstellung aperiodischer La/B{sub 4}C-Multischichtsysteme wurde zusaetzlich ein In-situ Ellipsometer in Betrieb genommen. Des Weiteren soll eine Senkung der Grenzflaechenrauigkeiten und damit einhergehende Erhoehung der Reflektivitaeten von La/B{sub 4}C-Multischichten durch das Polieren mit beschleunigten Ionen der

Constraining processes of landscape change with combined in situ cosmogenic 14C-10Be analysis

Science.gov (United States)

Hippe, Kristina

2017-10-01

Reconstructing Quaternary landscape evolution today frequently builds upon cosmogenic-nuclide surface exposure dating. However, the study of complex surface exposure chronologies on the 102-104 years' timescale remains challenging with the commonly used long-lived radionuclides (10Be, 26Al, 36Cl). In glacial settings, key points are the inheritance of nuclides accumulated in a rock surface during a previous exposure episode and (partial) shielding of a rock surface after the main deglaciation event, e.g. during phases of glacier readvance. Combining the short-lived in situ cosmogenic 14C isotope with 10Be dating provides a valuable approach to resolve and quantify complex exposure histories and burial episodes within Lateglacial and Holocene timescales. The first studies applying the in situ14C-10Be pair have demonstrated the great benefit from in situ14C analysis for unravelling complex glacier chronologies in various glacial environments worldwide. Moreover, emerging research on in situ14C in sedimentary systems highlights the capacity of combined in situ14C-10Be analysis to quantify sediment transfer times in fluvial catchments or to constrain changes in surface erosion rates. Nevertheless, further methodological advances are needed to obtain truly routine and widely available in situ14C analysis. Future development in analytical techniques has to focus on improving the analytical reproducibility, reducing the background level and determining more accurate muonic production rates. These improvements should allow extending the field of applications for combined in situ14C-10Be analysis in Earth surface sciences and open up a number of promising applications for dating young sedimentary deposits and the quantification of recent changes in surface erosion dynamics.

Phosphoenolpyruvate-dependent protein kinase enzyme I of Streptococcus faecalis: purification and properties of the enzyme and characterization of its active center

International Nuclear Information System (INIS)

Alpert, C.A.; Frank, R.; Stueber, K.D.; Deutscher, J.; Hengstenberg, W.

1985-01-01

Enzyme I, the phosphoenolpyruvate:protein phosphotransferase (EC 2.7.3.9), which is part of the bacterial phosphoenolpyruvate-(PEP) dependent phosphotransferase system, has been purified from Streptococcus faecalis by using a large-scale preparation. Size exclusion chromatography revealed a molecular weight of 140,000. On sodium dodecyl sulfate gels, enzyme I gave one band with a molecular weight of 70,000, indicating that enzyme I consists of two identical subunits. The first 59 amino acids of the amino-terminal part of the protein have been sequenced. It showed some similarities with enzyme I of Salmonella typhimurium. The active center of enzyme I has also been determined. After phosphorylation with [ 32 P]PEP, the enzyme was cleaved by using different proteases. Labeled peptides were isolated by high-performance liquid chromatography on a reversed-phase column. The amino acid composition or amino acid sequence of the peptides has been determined. The largest labeled peptide was obtained with Lys-C protease and had the following sequence: -Ala-Phe-Val-Thr-Asp-Ile-Gly- Gly-Arg-Thr-Ser-His*-Ser-Ala-Ile-Met-Ala-Arg-Ser-Leu-Glu-Ile-Pro-Ala- Ile-Val-Gly-Thr-Lys-. It has previously been shown that the phosphoryl group is bound to the N-3 position of a histidyl residue in phosphorylated enzyme I. The single His in position 12 of the above peptide must therefore carry the phosphoryl group

Effect of glycolate on the activity of ribulosediphosphate and phosphoenolpyruvate carboxylases in C/sub 3/ and C/sub 4/ plants at different O/sub 2/ concentrations

Energy Technology Data Exchange (ETDEWEB)

Popova, L; Dimitrova, O [Bylgarska Akademiya na Naukite, Sofia. Inst. po Fiziologiya na Rasteniyata

1981-01-01

The experiments are carried out with pisum and maize plants grown in a chamber under controlled conditions. The activity of the two enzymes is recorded by the amount of fixed H/sup 14/CO/sub 3/ in acid-stable products of the reactions. The effect of glycolate on the activity of the carboxylating enzymes is largely related to the effect of O/sub 2/ on the activity of the RuDP and PEP carboxylases. The stimulating effect of glucolate on the activity of the carboxylating enzymes is probably of a regulatory significance. An essential conclusion is that O/sub 2/ attacks C/sub 4/ photosynthesis not only on inhibiting the RuDP carboxylase in bundle sheath cells, but it also inhibits the activity of the main carboxylating enzyme in C/sub 4/ plants-the PEP carboxylase.

Homologous Transcription Factors DUX4 and DUX4c Associate with Cytoplasmic Proteins during Muscle Differentiation.

Directory of Open Access Journals (Sweden)

Eugénie Ansseau

Full Text Available Hundreds of double homeobox (DUX genes map within 3.3-kb repeated elements dispersed in the human genome and encode DNA-binding proteins. Among these, we identified DUX4, a potent transcription factor that causes facioscapulohumeral muscular dystrophy (FSHD. In the present study, we performed yeast two-hybrid screens and protein co-purifications with HaloTag-DUX fusions or GST-DUX4 pull-down to identify protein partners of DUX4, DUX4c (which is identical to DUX4 except for the end of the carboxyl terminal domain and DUX1 (which is limited to the double homeodomain. Unexpectedly, we identified and validated (by co-immunoprecipitation, GST pull-down, co-immunofluorescence and in situ Proximal Ligation Assay the interaction of DUX4, DUX4c and DUX1 with type III intermediate filament protein desmin in the cytoplasm and at the nuclear periphery. Desmin filaments link adjacent sarcomere at the Z-discs, connect them to sarcolemma proteins and interact with mitochondria. These intermediate filament also contact the nuclear lamina and contribute to positioning of the nuclei. Another Z-disc protein, LMCD1 that contains a LIM domain was also validated as a DUX4 partner. The functionality of DUX4 or DUX4c interactions with cytoplasmic proteins is underscored by the cytoplasmic detection of DUX4/DUX4c upon myoblast fusion. In addition, we identified and validated (by co-immunoprecipitation, co-immunofluorescence and in situ Proximal Ligation Assay as DUX4/4c partners several RNA-binding proteins such as C1QBP, SRSF9, RBM3, FUS/TLS and SFPQ that are involved in mRNA splicing and translation. FUS and SFPQ are nuclear proteins, however their cytoplasmic translocation was reported in neuronal cells where they associated with ribonucleoparticles (RNPs. Several other validated or identified DUX4/DUX4c partners are also contained in mRNP granules, and the co-localizations with cytoplasmic DAPI-positive spots is in keeping with such an association. Large muscle RNPs

The redox state and the phosphorylation state of the mannitol-specific carrier of the E. coli phosphoenolpyruvate-dependent phosphotransferase system

NARCIS (Netherlands)

Robillard, G.T.; Pas, H.H.; Gage, D.; Elferink, M.G.L.

1988-01-01

This review summarizes the recent developments in identifying the activity-linked cysteine as one of the phosphorylation sites on the mannitol-specific EII of the E. coli phosphoenolpyruvate-dependent mannitol transport system. Two phosphorylation sites have been identified, one being the HPr/P-HPr

Dicty_cDB: VHB884 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available *nlygsnql yss*np*ktsfnsktrwnk**c*snin*yfnyyf*wyfcwyekywlnynykiliin*lii ikiiiikiiiivlhyfkdaxk*in*kf Translated... 2004.12.24 Homology vs DNA Score E Sequences producing significant alignments: (bits) Value N DQ538352 |DQ538352.1 Bienertia si... aralocaspica phosphoenolpyruvate carboxylase mRNA, partial cds. 48 2e-07 2 DQ538354 |DQ538354.1 Suaeda eltoni...lmekk**n** kh*f*lnhqvkelqns*rni*krlai*virkh*myqecyhiy*i*lmlqnniiwldqlen hsstmkmi*si...tfry*nd**thknykcnlginkt*nsstr**npstfcfns*nlygsnql yss*np*ktsfnsktrwnk**c*snin*yfnyyf*wyfcwyekywlnynykiliin*lii ikiiiikiiiivlhyfkda

Covalently Immobilised Cytochrome C Imaged by In Situ Scanning Tunnelling Microscopy

DEFF Research Database (Denmark)

Andersen, Jens Enevold Thaulov; Olesen, Klaus G.; Danilov, Alexey I.

1997-01-01

In situ scanning tunnelling microscopy (STM) imaging of cytochrome c (cyt c) on polycrystalline Pt surfaces and on Au(lll) was achieved first by covalent immobilisation of 3-aminopropyltriethoxysilane (3-APTS) brought to react with oxide present on the Pt surfaces. Covalently bound 3-APTS forms...

Mesophyll conductance in Zea mays responds transiently to CO2 availability: implications for transpiration efficiency in C4 crops.

Science.gov (United States)

Kolbe, Allison R; Cousins, Asaph B

2018-03-01

Mesophyll conductance (g m ) describes the movement of CO 2 from the intercellular air spaces below the stomata to the site of initial carboxylation in the mesophyll. In contrast with C 3 -g m , little is currently known about the intraspecific variation in C 4 -g m or its responsiveness to environmental stimuli. To address these questions, g m was measured on five maize (Zea mays) lines in response to CO 2 , employing three different estimates of g m . Each of the methods indicated a significant response of g m to CO 2 . Estimates of g m were similar between methods at ambient and higher CO 2 , but diverged significantly at low partial pressures of CO 2 . These differences are probably driven by incomplete chemical and isotopic equilibrium between CO 2 and bicarbonate under these conditions. Carbonic anhydrase and phosphoenolpyruvate carboxylase in vitro activity varied significantly despite similar values of g m and leaf anatomical traits. These results provide strong support for a CO 2 response of g m in Z. mays, and indicate that g m in maize is probably driven by anatomical constraints rather than by biochemical limitations. The CO 2 response of g m indicates a potential role for facilitated diffusion in C 4 -g m . These results also suggest that water-use efficiency could be enhanced in C 4 species by targeting g m . © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

(FSP) of Al–TiC in situ composite

Indian Academy of Sciences (India)

An Al-5 wt% TiC composite was processed in situ using K2TiF6 and graphite in Al melt and subjected to FSP. Processing parameters for FSP were optimized to get a defect free stir zone and homogenize the particle distribution. It was found that a rotation speed > 800 rpm is needed. A rotation speed of 1000 rpm and a ...

Electrochemical Performance of LixMn2-yFeyO4-zClz Synthesized Through In-Situ Glycine Nitrate Combustion

Science.gov (United States)

2016-06-13

Electrochemical Performance of LixMn2-yFeyO4-zClz Synthesized Through In-Situ Glycine Nitrate Combustion Ashley L. Ruth, Paula C. Latorre, and...sites as well as the formation of Mn3+ ions via the Jahn- Teller effect. The use of the glycine nitrate combustion synthesis produces small particles at...advantage of submicron ceramic synthesis, namely the glycine nitrate combustion process (GNP), we propose the capability for in-situ B-site doping

Cytosolic Phosphoenolpyruvate Carboxykinase Does Not Solely Control the Rate of Hepatic Gluconeogenesis in the Intact Mouse Liver

OpenAIRE

Burgess, Shawn C.; He, TianTeng; Yan, Zheng; Lindner, Jill; Sherry, A. Dean; Malloy, Craig R.; Browning, Jeffrey D.; Magnuson, Mark A.

2007-01-01

When dietary carbohydrate is unavailable, glucose required to support metabolism in vital tissues is generated via gluconeogenesis in the liver. Expression of phosphoenolpyruvate carboxykinase (PEPCK), commonly considered the control point for liver gluconeogenesis, is normally regulated by circulating hormones to match systemic glucose demand. However, this regulation fails in diabetes. Because other molecular and metabolic factors can also influence gluconeogenesis, the explicit role of PEP...

Study of influence content of TiB2 by reaction in situ B4C and TiC in mechanical properties on B4C ceramics

International Nuclear Information System (INIS)

Coelho, M.L. Ramos; Bressiani, J.C.; Gomide, R.G.; Andrade, F.A. de

2012-01-01

The low density of ceramic materials promoted a change in research lines in the defense field. Research efforts and development directed to obtaining products of high density sintered of Al2O3, SiC and B4C, using different routes, both traditional as innovative, led to promising initial results, which justify the convergence of skills for the consolidation of research lines and the nationalization that sintered components of B4C with characteristics and properties compatible with the technical requirements established for the ballistic application. The low density of boron carbide (2.52 g/cm 3 ) gives in the final product a weight approximately 30% lower than armor made of alumina (3.96 g/cm 3 ). (author)

A Role for Mitochondrial Phosphoenolpyruvate Carboxykinase (PEPCK-M) in the Regulation of Hepatic Gluconeogenesis*

Science.gov (United States)

Stark, Romana; Guebre-Egziabher, Fitsum; Zhao, Xiaojian; Feriod, Colleen; Dong, Jianying; Alves, Tiago C.; Ioja, Simona; Pongratz, Rebecca L.; Bhanot, Sanjay; Roden, Michael; Cline, Gary W.; Shulman, Gerald I.; Kibbey, Richard G.

2014-01-01

Synthesis of phosphoenolpyruvate (PEP) from oxaloacetate is an absolute requirement for gluconeogenesis from mitochondrial substrates. Generally, this reaction has solely been attributed to the cytosolic isoform of PEPCK (PEPCK-C), although loss of the mitochondrial isoform (PEPCK-M) has never been assessed. Despite catalyzing the same reaction, to date the only significant role reported in mammals for the mitochondrial isoform is as a glucose sensor necessary for insulin secretion. We hypothesized that this nutrient-sensing mitochondrial GTP-dependent pathway contributes importantly to gluconeogenesis. PEPCK-M was acutely silenced in gluconeogenic tissues of rats using antisense oligonucleotides both in vivo and in isolated hepatocytes. Silencing PEPCK-M lowers plasma glucose, insulin, and triglycerides, reduces white adipose, and depletes hepatic glycogen, but raises lactate. There is a switch of gluconeogenic substrate preference to glycerol that quantitatively accounts for a third of glucose production. In contrast to the severe mitochondrial deficiency characteristic of PEPCK-C knock-out livers, hepatocytes from PEPCK-M-deficient livers maintained normal oxidative function. Consistent with its predicted role, gluconeogenesis rates from hepatocytes lacking PEPCK-M are severely reduced for lactate, alanine, and glutamine, but not for pyruvate and glycerol. Thus, PEPCK-M has a direct role in fasted and fed glucose homeostasis, and this mitochondrial GTP-dependent pathway should be reconsidered for its involvement in both normal and diabetic metabolism. PMID:24497630

A role for mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) in the regulation of hepatic gluconeogenesis.

Science.gov (United States)

Stark, Romana; Guebre-Egziabher, Fitsum; Zhao, Xiaojian; Feriod, Colleen; Dong, Jianying; Alves, Tiago C; Ioja, Simona; Pongratz, Rebecca L; Bhanot, Sanjay; Roden, Michael; Cline, Gary W; Shulman, Gerald I; Kibbey, Richard G

2014-03-14

Synthesis of phosphoenolpyruvate (PEP) from oxaloacetate is an absolute requirement for gluconeogenesis from mitochondrial substrates. Generally, this reaction has solely been attributed to the cytosolic isoform of PEPCK (PEPCK-C), although loss of the mitochondrial isoform (PEPCK-M) has never been assessed. Despite catalyzing the same reaction, to date the only significant role reported in mammals for the mitochondrial isoform is as a glucose sensor necessary for insulin secretion. We hypothesized that this nutrient-sensing mitochondrial GTP-dependent pathway contributes importantly to gluconeogenesis. PEPCK-M was acutely silenced in gluconeogenic tissues of rats using antisense oligonucleotides both in vivo and in isolated hepatocytes. Silencing PEPCK-M lowers plasma glucose, insulin, and triglycerides, reduces white adipose, and depletes hepatic glycogen, but raises lactate. There is a switch of gluconeogenic substrate preference to glycerol that quantitatively accounts for a third of glucose production. In contrast to the severe mitochondrial deficiency characteristic of PEPCK-C knock-out livers, hepatocytes from PEPCK-M-deficient livers maintained normal oxidative function. Consistent with its predicted role, gluconeogenesis rates from hepatocytes lacking PEPCK-M are severely reduced for lactate, alanine, and glutamine, but not for pyruvate and glycerol. Thus, PEPCK-M has a direct role in fasted and fed glucose homeostasis, and this mitochondrial GTP-dependent pathway should be reconsidered for its involvement in both normal and diabetic metabolism.

Altered expression of the urokinase receptor homologue, C4.4A, in invasive areas of human esophageal squamous cell carcinoma

DEFF Research Database (Denmark)

Hansen, L.V.; Laerum, O.D.; Illemann, M.

2008-01-01

. In the present study, we have therefore analyzed the expression of C4.4A in 14 esophageal squamous cell carcinomas (ESCC). Normal squamous esophageal epithelium shows a strong cell surface associated C4.4A expression in the suprabasal layers, whereas basal cells are negative. Upon transition to dysplasia...... and carcinoma in situ the expression of C4.4A is abruptly and coordinately weakened. Double immunofluorescence staining of normal and dysplastic tissue showed that C4.4A colocalizes with the epithelial cell surface marker E-cadherin in the suprabasal cells and has a complementary expression pattern compared...... to the proliferation marker Ki-67. A prominent, but frequently intracellular, C4.4A expression reappeared in tumor cells located at the invasive front and local lymph node metastases. Because C4.4A was reported previously to be a putative laminin-5 (LN5) ligand, and both proteins are expressed by invasive tumor cells...

In-situ Observation of Fracture Behavior on Nano Structure in NITE SiC/SiC Composite by HVEM

International Nuclear Information System (INIS)

Shibayama, Tamaki; Hamada, Kouichi; Watanabe, Seiichi; Matsuo, Genichiro; Kishimoto, Hirotatsu

2011-01-01

We have been successfully done in situ observation on the sequence of fracture event at the interface of NITE SiC/SiC composite examined by using miniaturized double notched shear specimen for TEM prepared by Focused Ion Beam method. In this study, we used nano-mechanics TEM experimental apparatus to investigate not only microstructure evolution and but also load and displacement curve at once in High Voltage Electron Microscope. Our results summarize as follows. Cracks were initiated at the interface between carbon coating layer on the SiC fiber and SiC matrices, and propagated along the interface. Load drop in the load and displacement curve during in-situ TEM was clearly observed at the crack initiation. The shear strength by using the miniaturized specimen is about ten times higher than that obtained by the standard testing.

Product evaluation of in situ vitrification engineering, Test 4

International Nuclear Information System (INIS)

Loehr, C.A.; Weidner, J.R.; Bates, S.O.

1991-09-01

This report is one of several that evaluates the In Situ Vitrification (ISV) Engineering-Scale Test 4 (ES-4). This document describes the chemical and physical composition, microstructure, and leaching characteristics of ES-4 product samples; these data provide insight into the expected performance of a vitrified product in an ISV buried waste application similar to that studied in ES-4

Determination of the initial oxidation behavior of Zircaloy-4 by in-situ TEM

International Nuclear Information System (INIS)

Harlow, Wayne; Ghassemi, Hessam; Taheri, Mitra L.

2016-01-01

The corrosion behavior of Zircaloy-4 (Zry-4), specifically by oxidation, is a problem of great importance as this material is critical for current nuclear reactor cladding. The early formation behavior and structure of the oxide layer during oxidation was studied using in-situ TEM techniques that allowed for Zry-4 to be monitored during corrosion. These environmental exposure experiments were coupled with precession electron diffraction to identify and quantify the phases present in the samples before and after the oxidation. Following short-term, high temperature oxidation, the dominant phase was revealed to be monoclinic ZrO 2 in a columnar structure. These samples oxidized in-situ contained structures that correlated well with bulk Zry-4 subjected to autoclave treatment, which were used for comparison and validation of this technique. By using in-situ TEM the effect of microstructure features, such as grain boundaries, on oxidation behavior of an alloy can be studied. The technique presented herein holds the potential to be applied any alloy system to study these effects. - Highlights: • In-situ TEM was used to oxidize samples of Zircaloy-4. • Similar behavior was found in the in-situ oxidized and autoclave-oxidized samples. • Precession diffraction was used to characterize oxide phase and texture.

Consequences of C4 differentiation for chloroplast membrane proteomes in maize mesophyll and bundle sheath cells.

Science.gov (United States)

Majeran, Wojciech; Zybailov, Boris; Ytterberg, A Jimmy; Dunsmore, Jason; Sun, Qi; van Wijk, Klaas J

2008-09-01

Chloroplasts of maize leaves differentiate into specific bundle sheath (BS) and mesophyll (M) types to accommodate C(4) photosynthesis. Chloroplasts contain thylakoid and envelope membranes that contain the photosynthetic machineries and transporters but also proteins involved in e.g. protein homeostasis. These chloroplast membranes must be specialized within each cell type to accommodate C(4) photosynthesis and regulate metabolic fluxes and activities. This quantitative study determined the differentiated state of BS and M chloroplast thylakoid and envelope membrane proteomes and their oligomeric states using innovative gel-based and mass spectrometry-based protein quantifications. This included native gels, iTRAQ, and label-free quantification using an LTQ-Orbitrap. Subunits of Photosystems I and II, the cytochrome b(6)f, and ATP synthase complexes showed average BS/M accumulation ratios of 1.6, 0.45, 1.0, and 1.33, respectively, whereas ratios for the light-harvesting complex I and II families were 1.72 and 0.68, respectively. A 1000-kDa BS-specific NAD(P)H dehydrogenase complex with associated proteins of unknown function containing more than 15 proteins was observed; we speculate that this novel complex possibly functions in inorganic carbon concentration when carboxylation rates by ribulose-bisphosphate carboxylase/oxygenase are lower than decarboxylation rates by malic enzyme. Differential accumulation of thylakoid proteases (Egy and DegP), state transition kinases (STN7,8), and Photosystem I and II assembly factors was observed, suggesting that cell-specific photosynthetic electron transport depends on post-translational regulatory mechanisms. BS/M ratios for inner envelope transporters phosphoenolpyruvate/P(i) translocator, Dit1, Dit2, and Mex1 were determined and reflect metabolic fluxes in carbon metabolism. A wide variety of hundreds of other proteins showed differential BS/M accumulation. Mass spectral information and functional annotations are

Implications for Extraterrestrial Hydrocarbon Chemistry: Analysis of Ethylene (C{sub 2}H{sub 4}) and D4-Ethylene (C{sub 2}D{sub 4}) Ices Exposed to Ionizing Radiation via Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Abplanalp, Matthew J.; Kaiser, Ralf I., E-mail: ralfk@hawaii.edu [W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

2017-02-20

The processing of the hydrocarbon ice, ethylene (C{sub 2}H{sub 4}/C{sub 2}D{sub 4}), via energetic electrons, thus simulating the processes in the track of galactic cosmic-ray particles, was carried out in an ultrahigh vacuum apparatus. The chemical evolution of the ices was monitored online and in situ utilizing Fourier transform infrared spectroscopy (FTIR) and during temperature programmed desorption, via a quadrupole mass spectrometer utilizing electron impact ionization (EI-QMS) and a reflectron time-of-flight mass spectrometer utilizing a photoionization source (PI-ReTOF-MS). Several previous in situ studies of ethylene ice irradiation using FTIR were substantiated with the detection of six products: [CH{sub 4} (CD{sub 4})], acetylene [C{sub 2}H{sub 2} (C{sub 2}D{sub 2})], the ethyl radical [C{sub 2}H{sub 5} (C{sub 2}D{sub 5})], ethane [C{sub 2}H{sub 6} (C{sub 2}D{sub 6})], 1-butene [C{sub 4}H{sub 8} (C{sub 4}D{sub 8})], and n -butane [C{sub 4}H{sub 10} (C{sub 4}D{sub 10})]. Contrary to previous gas phase studies, the PI-ReTOF-MS detected several groups of hydrocarbon with varying degrees of saturation: C{sub n}H{sub 2n+2} (n = 4–10), C{sub n}H{sub 2n} ( n = 2–12, 14, 16), C{sub n}H{sub 2n−2} ( n = 3–12, 14, 16), C{sub n}H{sub 2n−4} (n = 4–12, 14, 16), C{sub n}H{sub 2n−6} (n = 4–10, 12), C{sub n}H{sub 2n−8} ( n = 6–10), and C{sub n}H{sub 2n−10} ( n = 6–10). Multiple laboratory studies have shown the facile production of ethylene from methane, which is a known ice constituent in the interstellar medium. Various astrophysically interesting molecules can be associated with the groups detected here, such as allene/methylacetylene (C{sub 3}H{sub 4}) or 1, 3-butadiene (C{sub 4}H{sub 6}) and its isomers, which have been shown to lead to polycyclic aromatic hydrocarbons. Finally, several hydrocarbon groups detected here are unique to ethylene ice versus ethane ice and may provide understanding of how complex hydrocarbons form in astrophysical

Interface engineered construction of porous g-C3N4/TiO2 heterostructure for enhanced photocatalysis of organic pollutants

Science.gov (United States)

Li, Ya-Nan; Chen, Zhao-Yang; Wang, Min-Qiang; Zhang, Long-zhen; Bao, Shu-Juan

2018-05-01

A porous g-C3N4/TiO2 with hierarchical heterostructure has been successfully fabricated through a in situ assembling of small needle-like TiO2 on the surface of ultrathin g-C3N4 sheets. The ultrathin g-C3N4 sheets with carbon vacancies and rich hydroxyl groups were found to facilitate the nucleation and in situ growth of TiO2 and also to modulate the surface chemical activity of the g-C3N4/TiO2 hierarchical heterostructure. The as-designed photocatalytic heterojunction degraded Acid Orange with 82% efficiency after 10 min under simulated solar light, and possessed excellent cycle stability. Relative physical characterizations and photochemical experiments reveal that engineering the interface/surface of g-C3N4 plays a vital role in effectively constructing heterostructures of g-C3N4/TiO2, thus realizing efficient photoinduced electron-hole separation during photocatalytic process.

Fabrication of modified g-C3N4 nanorod/Ag3PO4 nanocomposites for solar-driven photocatalytic oxygen evolution from water splitting

Science.gov (United States)

Tian, Lin; Xian, Xiaozhai; Cui, Xingkai; Tang, Hua; Yang, Xiaofei

2018-02-01

Semiconductor-based photocatalysis has been considered as one of the most effective techniques to achieve the conversion of clean and sustainable sunlight to solar fuel, in which the construction of novel solar-driven photocatalytic systems is the key point. Here, we report initially the synthesis of modified graphitic carbon nitride (g-C3N4) nanorods via the calcination of intermediates obtained from the co-polymerization of precursors, and the in-situ hybridization of Ag3PO4 with as-prepared modified g-C3N4 to produce g-C3N4 nanorod/Ag3PO4 composite materials. The diameter of modified rod-like g-C3N4 materials is determined to be around 1 μm. Subsequently the morphological features, crystal and chemical structures of the assembled g-C3N4 nanorod/Ag3PO4 composites were systematically investigated by SEM, XRD, XPS, UV-vis diffuse reflectance spectra (DRS). Furthermore, the use of as-prepared composite materials as the catalyst for photocatalytic oxygen evolution from water splitting was studied. The oxygen-generating results showed that the composite photocatalyst modified with 600 mg rod-like g-C3N4 demonstrates 2.5 times higher efficiency than that of bulk Ag3PO4. The mechanism behind the enhancement in the oxygen-evolving activity is proposed on the basis of in-situ electron spin resonance (ESR) measurement as well as theoretical analysis. The study provides new insights into the design and development of new photocatalytic composite materials for energy and environmental applications.

Fabrication of SiC Composites with Synergistic Toughening of Carbon Whisker and In Situ 3C-SiC Nanowire

Directory of Open Access Journals (Sweden)

Zhang Yunlong

2016-01-01

Full Text Available The SiC composites with synergistic toughening of carbon whisker and in situ 3C-SiC nanowire have been fabricated by hot press sinter technology and annealed treatment technology. Effect of annealed time on the morphology of SiC nanowires and mechanical properties of the Cw/SiC composites was surveyed in detail. The appropriate annealed time improved mechanical properties of the Cw/SiC composites. The synergistic effect of carbon whisker and SiC nanowire can improve the fracture toughness for Cw/SiC composites. The vapor-liquid-solid growth (VLS mechanism was proposed. TEM photo showed that 3C-SiC nanowire can be obtained with preferential growth plane ({111}, which corresponded to interplanar spacing about 0.25 nm.

Crystal structures of Er4Ni13C4 and UW4C4

International Nuclear Information System (INIS)

Khalili, M.M.; Bodak, O.I.; Marusin, E.P.; Pecharskaya, A.O.

1990-01-01

Crystal structures of Er 4 Ni 13 C 4 (1) (sp.gr. Cmmm, a=1.1975(4), b=1.1694(3), c=0.3856(1) nm, Z=2) and UW 4 C 4 (2) (sp.gr. P4/m, a=0.8328(8), c=0.31345(9) nm, Z=2), relating to new types are determined. Structural type (1) is a derivative of La 2 Ni 5 C 3 structure, structural type (2) is close to UCr 4 C 4 structure

In situ fabrication of novel Z-scheme Bi{sub 2}WO{sub 6} quantum dots/g-C{sub 3}N{sub 4} ultrathin nanosheets heterostructures with improved photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Chen, Wei; Liu, Tian-Yu; Huang, Ting; Liu, Xiao-Heng, E-mail: xhliu@mail.njust.edu.cn; Zhu, Jun-Wu; Duan, Guo-Rong; Yang, Xu-Jie

2015-11-15

Graphical abstract: - Highlights: • We designed and fabricated novel Bi{sub 2}WO{sub 6} QDs/g-C{sub 3}N{sub 4} heterojunction structures. • Novel Bi{sub 2}WO{sub 6} QDs/g-C{sub 3}N{sub 4} catalysts were constructed by one-pot hydrothermal route. • The catalysts show highly efficient solar light catalytic activity. • Z-scheme mechanism was proposed to explain the enhanced catalytic activity. - Abstract: The use of solar energy is a promising means for pollution abatement or environmental remediation. In the present work, we report the design and fabrication of Bi{sub 2}WO{sub 6} QDs/g-C{sub 3}N{sub 4} binary heterojunction photocatalysts with highly efficient solar light response, wherein the Bi{sub 2}WO{sub 6} QDs were in situ uniformly immobilized on porous g-C{sub 3}N{sub 4} ultrathin nanosheets (NSs) by one-pot hydrothermal strategy. The photocatalytic performance of the Bi{sub 2}WO{sub 6} QDs/g-C{sub 3}N{sub 4} NSs hybrid composites was evaluated for the photodegradation of Rhodamine B (RhB). It was found that the mass ratio of Bi{sub 2}WO{sub 6} QDs to g-C{sub 3}N{sub 4} nanosheets in the composites significantly affects the photocatalytic activity. Higher amounts of g-C{sub 3}N{sub 4} nanosheets in Bi{sub 2}WO{sub 6} QDs/g-C{sub 3}N{sub 4} composites showed lower photocatalytic activity. The composite with 10 mg g-C{sub 3}N{sub 4} nanosheets exhibited the highest photocatalytic activity, with nearly 11-fold enhancement in photocatalytic efficiency over pure Bi{sub 2}WO{sub 6} QDs. Different from previous reports, a novel Z-scheme photocatalytic mechanism was proposed to explain the enhanced the photocatalytic efficiency.

Escherichia coli Phosphoenolpyruvate Dependent Phosphotransferase System. NMR Studies of the Conformation of HPr and P-HPr and the Mechanism of Energy Coupling

NARCIS (Netherlands)

Dooijewaard, G.; Roossien, F.F.; Robillard, G.T.

1979-01-01

1H and 31P nuclear magnetic resonance investigations of the phosphoprotein intermediate P-HPr and the parent molecule HPr of the E. coli phosphoenolpyruvate dependent phosphotransferase system (PTS) show that HPr can exist in two conformations. These conformations influence the protonation state of

In situ synthesis of g-C3N4/TiO2 heterojunction nanocomposites as a highly active photocatalyst for the degradation of Orange II under visible light irradiation.

Science.gov (United States)

Ren, Bin; Wang, Tiecheng; Qu, Guangzhou; Deng, Fang; Liang, Dongli; Yang, Wenli; Liu, Meishan

2018-05-04

As a highly active photocatalyst, g-C 3 N 4 /TiO 2 heterojunction nanocomposites were in situ synthesized by simple ultrasonic mixing and calcination by using TiO 2 and melamine as precursors. The morphology and structure of the prepared photocatalysts were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic activities of g-C 3 N 4 /TiO 2 nanocomposites to degrade Orange II (AO7) under visible light irradiation were evaluated. Results showed that the photocatalytic rate of the prepared g-C 3 N 4 /TiO 2 photocatalyst to degrade AO7 was about three times than that of pristine TiO 2 and g-C 3 N 4 . The g-C 3 N 4 /TiO 2 composite with a ratio of 1:4 had the highest degradation efficiency for AO7 solution. Its degradation efficiency under acidic conditions was significantly higher than that under alkaline conditions. The enhancement of photocatalytic activity can be attributed to the formation of heterojunctions between g-C 3 N 4 and TiO 2 , which leads to rapid charge transfer and the efficient separation of photogenerated electron-hole pairs. The recycling experiment indicated that the photocatalyst of g-C 3 N 4 /TiO 2 nanocomposites still maintained good photochemical stability and recyclability after five cycles; this finding was important for its practical applications. A series of free radical trapping experiments showed that •O 2 - played a crucial role in the degradation of AO7. Graphical Abstract ᅟ.

In situ and ex situ characterization of the ion-irradiation effects in third generation SiC fibers

International Nuclear Information System (INIS)

Huguet-Garcia, Juan

2015-01-01

The use of third generation SiC fibers, Tyranno SA3 (TSA3) and Hi Nicalon S (HNS), as reinforcement for ceramic composites for nuclear applications requires the characterization of its structural stability and mechanical behavior under irradiation. Regarding the radiation stability, ion-amorphization kinetics of these fibers have been studied and compared to the model material, i.e. 6H-SiC single crystals, with no significant differences. For all samples, full amorphization threshold dose yields ∼0.4 dpa at room temperature and complete amorphization was not achieved for irradiation temperatures over 200 C. Successively, ion-amorphized samples have been thermally annealed. It is reported that thermal annealing at high temperatures not only induces the recrystallization of the ion-amorphized samples but also causes unrecoverable mechanical failure, i.e. cracking and delamination. Cracking is reported to be a thermally driven phenomenon characterized by activation energy of 1.05 eV. Regarding the mechanical irradiation behavior, irradiation creep of TSA3 fibers has been investigated using a tensile device dedicated to in situ tests coupled to two different ion-irradiation lines. It is reported that ion irradiation (12 MeV C 4+ and 92 MeV Xe 23+ ) induces a time-dependent strain under loads where thermal creep is negligible. In addition, irradiation strain is reported to be higher at low irradiation temperatures due to a coupling between irradiation swelling and irradiation creep. At high temperatures, near 1000 C, irradiation swelling is minimized hence allowing the characterization of the irradiation creep. Irradiation creep rate is characterized by a linear correlation between the ion flux and the strain rate and a square root dependence with the applied load. Finally, it has been reported that the higher the electronic energy loss contribution to the stopping regime the higher the irradiation creep of the fiber. (author) [fr

Effect of Mo on Microstructures and Wear Properties of In Situ Synthesized Ti(C,N)/Ni-Based Composite Coatings by Laser Cladding.

Science.gov (United States)

Wu, Fan; Chen, Tao; Wang, Haojun; Liu, Defu

2017-09-06

Using Ni60 alloy, C, TiN and Mo mixed powders as the precursor materials, in situ synthesized Ti(C,N) particles reinforcing Ni-based composite coatings are produced on Ti6Al4V alloys by laser cladding. Phase constituents, microstructures and wear properties of the composite coatings with 0 wt % Mo, 4 wt % Mo and 8 wt % Mo additions are studied comparatively. Results indicate that Ti(C,N) is formed by the in situ metallurgical reaction, the (Ti,Mo)(C,N) rim phase surrounding the Ti(C,N) ceramic particle is synthesized with the addition of Mo, and the increase of Mo content is beneficial to improve the wear properties of the cladding coatings. Because of the effect of Mo, the grains are remarkably refined and a unique core-rim structure that is uniformly dispersed in the matrix appears; meanwhile, the composite coatings with Mo addition exhibit high hardness and excellent wear resistance due to the comprehensive action of dispersion strengthening, fine grain strengthening and solid solution strengthening.

Robust Control of PEP Formation Rate in the Carbon Fixation Pathway of C4 Plants by a Bi-functional Enzyme

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Hart Yuval

2011-10-01

Full Text Available Abstract Background C4 plants such as corn and sugarcane assimilate atmospheric CO2 into biomass by means of the C4 carbon fixation pathway. We asked how PEP formation rate, a key step in the carbon fixation pathway, might work at a precise rate, regulated by light, despite fluctuations in substrate and enzyme levels constituting and regulating this process. Results We present a putative mechanism for robustness in C4 carbon fixation, involving a key enzyme in the pathway, pyruvate orthophosphate dikinase (PPDK, which is regulated by a bifunctional enzyme, Regulatory Protein (RP. The robust mechanism is based on avidity of the bifunctional enzyme RP to its multimeric substrate PPDK, and on a product-inhibition feedback loop that couples the system output to the activity of the bifunctional regulator. The model provides an explanation for several unusual biochemical characteristics of the system and predicts that the system's output, phosphoenolpyruvate (PEP formation rate, is insensitive to fluctuations in enzyme levels (PPDK and RP, substrate levels (ATP and pyruvate and the catalytic rate of PPDK, while remaining sensitive to the system's input (light levels. Conclusions The presented PPDK mechanism is a new way to achieve robustness using product inhibition as a feedback loop on a bifunctional regulatory enzyme. This mechanism exhibits robustness to protein and metabolite levels as well as to catalytic rate changes. At the same time, the output of the system remains tuned to input levels.

Synthesis of 1,2,4-Triazoles via Oxidative Heterocyclization: Selective C-N Bond Over C-S Bond Formation.

Science.gov (United States)

Gogoi, Anupal; Guin, Srimanta; Rajamanickam, Suresh; Rout, Saroj Kumar; Patel, Bhisma K

2015-09-18

The higher propensity of C-N over C-S bond forming ability was demonstrated, through formal C-H functionalization during the construction of 4,5-disubstituted 1,2,4-triazole-3-thiones from arylidenearylthiosemicarbazides catalyzed by Cu(II). However, steric factors imparted by the o-disubstituted substrates tend to change the reaction path giving thiodiazole as the major or an exclusive product. Upon prolonging the reaction time, the in situ generated thiones are transformed to 4,5-disubstituted 1,2,4-triazoles via a desulfurization process. Two classes of heterocycles viz. 4,5-disubstituted 1,2,4-triazole-3-thiones and 4,5-disubstituted 1,2,4-triazoles can be synthesized from arylidenearylthiosemicarbazides by simply adjusting the reaction time. Desulfurization of 1,2,4-triazole-3-thiones is assisted by thiophilic Cu to provide 1,2,4-triazoles with concomitant formation of CuS and polynuclear sulfur anions as confirmed from scanning electron microscope and energy dispersive X-ray spectroscopy measurements. A one-pot synthesis of an antimicrobial compound has been successfully achieved following this strategy.

In-situ anatase phase stabilization of titania photocatalyst by sintering in presence of Zr4+ organic salts

International Nuclear Information System (INIS)

Strini, Alberto; Sanson, Alessandra; Mercadelli, Elisa; Bendoni, Riccardo; Marelli, Marcello; Dal Santo, Vladimiro; Schiavi, Luca

2015-01-01

Graphical abstract: - Highlights: • Existing commercial (P25) anatase was stabilized in-situ with Zr(IV) doping. • Highly active catalytic layers were obtained by screen-printing. • Increased thermal stability was demonstrated up to 200 °C without activity loss. • Enhanced activity was obtained because of the Zr(IV) doping. • Zirconium diffusion was assessed by STEM-EDS analysis. - Abstract: The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degussa P25) was obtained by sintering the catalyst powder in presence of Zr 4+ organic salts. This approach allows the doping of an already-formed nanocrystalline photocatalyst instead of introducing the dopant in the crystal lattice during the catalyst synthesis. The procedure was demonstrated by the production of thick ceramic layers using the screen printing technique. This new method allows to easily stabilize the anatase phase 200 °C higher than the undoped P25 maintaining the same photocatalytic activity. The process was studied using specifically formulated screen-printing inks added with Zr 4+ organic salt at 1% and 2% Zr/Ti molar ratio. The anatase phase stability was investigated in the 500–900 °C temperature range analysing the resulting catalysts with XRD, TEM and (S)TEM-EDS. The catalytic activity of the screen-printed layers was assessed by measuring the degradation of toluene in air at ambient concentration (500 nmol m −3 ) and low UV-A irradiance (180 μW cm −2 ). The described in-situ stabilization method could be potentially applied to any deposition process involving already formed anatase photocatalyst, allowing higher sintering temperature and then an improved mechanical stability of the active layers without photocatalytic activity degradation

Revealing fosfomycin primary effect on Staphylococcus aureus transcriptome: modulation of cell envelope biosynthesis and phosphoenolpyruvate induced starvation

Directory of Open Access Journals (Sweden)

Gruden Kristina

2010-06-01

Full Text Available Abstract Background Staphylococcus aureus is a highly adaptable human pathogen and there is a constant search for effective antibiotics. Fosfomycin is a potent irreversible inhibitor of MurA, an enolpyruvyl transferase that uses phosphoenolpyruvate as substrate. The goal of this study was to identify the pathways and processes primarily affected by fosfomycin at the genome-wide transcriptome level to aid development of new drugs. Results S. aureus ATCC 29213 cells were treated with sub-MIC concentrations of fosfomycin and harvested at 10, 20 and 40 minutes after treatment. S. aureus GeneChip statistical data analysis was complemented by gene set enrichment analysis. A visualization tool for mapping gene expression data into biological pathways was developed in order to identify the metabolic processes affected by fosfomycin. We have shown that the number of significantly differentially expressed genes in treated cultures increased with time and with increasing fosfomycin concentration. The target pathway - peptidoglycan biosynthesis - was upregulated following fosfomycin treatment. Modulation of transport processes, cofactor biosynthesis, energy metabolism and nucleic acid biosynthesis was also observed. Conclusions Several pathways and genes downregulated by fosfomycin have been identified, in contrast to previously described cell wall active antibiotics, and was explained by starvation response induced by phosphoenolpyruvate accumulation. Transcriptomic profiling, in combination with meta-analysis, has been shown to be a valuable tool in determining bacterial response to a specific antibiotic.

Deformation-induced phase transformation in 4H–SiC nanopillars

International Nuclear Information System (INIS)

Chen, Bin; Wang, Jun; Zhu, Yiwei; Liao, Xiaozhou; Lu, Chunsheng; Mai, Yiu-Wing; Ringer, Simon P.; Ke, Fujiu; Shen, Yaogen

2014-01-01

The deformation behaviour of single-crystal SiC nanopillars was studied by a combination of in situ deformation transmission electron microscopy and molecular dynamics simulations. An unexpected deformation-induced phase transformation from the 4H hexagonal structure to the 3C face-centred cubic structure was observed in these nanopillars at room temperature. Atomistic simulations revealed that the 4H to 3C phase transformation follows a stick–slip process with initiation and end stresses of 12.1–14.0 and 7.9–9.0 GPa, respectively. The experimentally measured stress of 9–10 GPa for the phase transformation falls within the range of these theoretical upper and lower stresses. The reasons for the phase transformation are discussed. The finding sheds light on the understanding of phase transformation in polytypic materials at low temperature

Interlayer growth in Mo/B4C multilayered structures upon thermal annealing

International Nuclear Information System (INIS)

Nyabero, S. L.; Kruijs, R. W. E. van de; Yakshin, A. E.; Zoethout, E.; Bosgra, J.; Loch, R. A.; Blanckenhagen, G. von; Bijkerk, F.

2013-01-01

Both multilayer period thickness expansion and compaction were observed in Mo/B 4 C multilayers upon annealing, and the physical causes for this were explored in detail. Using in situ time-dependent grazing incidence X-ray reflectometry, period changes down to picometer-scale were resolved. It was shown that the changes depend on the thickness of the B 4 C layers, annealing temperature, and annealing time. Although strong stress relaxation during annealing was observed, it was excluded as a cause for period expansion. Auger electron spectroscopy and wide angle X-ray diffraction measurements revealed the growth of interlayers, with associated period changes influenced by the supply of B and C atoms to the growing compound interlayers. For multilayers with a Mo thickness of 3 nm, two regimes were recognized, depending on the deposited B 4 C thickness: in multilayers with B 4 C ≤ 1.5 nm, the supply of additional Mo into the already formed MoB x C y interlayer was dominant and led to densification, resulting in period compaction. For multilayers with B 4 C ≥ 2 nm, the B and C enrichment of interlayers formed low density compounds and yielded period expansion.

Discrimination in the Dark. Resolving the Interplay between Metabolic and Physical Constraints to Phosphoenolpyruvate Carboxylase Activity during the Crassulacean Acid Metabolism Cycle1

Science.gov (United States)

Griffiths, Howard; Cousins, Asaph B.; Badger, Murray R.; von Caemmerer, Susanne

2007-01-01

A model defining carbon isotope discrimination (Δ13C) for crassulacean acid metabolism (CAM) plants was experimentally validated using Kalanchoe daigremontiana. Simultaneous measurements of gas exchange and instantaneous CO2 discrimination (for 13C and 18O) were made from late photoperiod (phase IV of CAM), throughout the dark period (phase I), and into the light (phase II). Measurements of CO2 response curves throughout the dark period revealed changing phosphoenolpyruvate carboxylase (PEPC) capacity. These systematic changes in PEPC capacity were tracked by net CO2 uptake, stomatal conductance, and online Δ13C signal; all declined at the start of the dark period, then increased to a maximum 2 h before dawn. Measurements of Δ13C were higher than predicted from the ratio of intercellular to external CO2 (pi/pa) and fractionation associated with CO2 hydration and PEPC carboxylations alone, such that the dark period mesophyll conductance, gi, was 0.044 mol m−2 s−1 bar−1. A higher estimate of gi (0.085 mol m−2 s−1 bar−1) was needed to account for the modeled and measured Δ18O discrimination throughout the dark period. The differences in estimates of gi from the two isotope measurements, and an offset of −5.5‰ between the 18O content of source and transpired water, suggest spatial variations in either CO2 diffusion path length and/or carbonic anhydrase activity, either within individual cells or across a succulent leaf. Our measurements support the model predictions to show that internal CO2 diffusion limitations within CAM leaves increase Δ13C discrimination during nighttime CO2 fixation while reducing Δ13C during phase IV. When evaluating the phylogenetic distribution of CAM, carbon isotope composition will reflect these diffusive limitations as well as relative contributions from C3 and C4 biochemistry. PMID:17142488

Synthesis, Characterization, Antimicrobial and Antioxidant Activities of The Homocyclotrimer Of 4-Oxo-4h-Thieno[3,4-C]Chromene-3-Diazonium Sulfate.

Science.gov (United States)

Sopbue Fondjo, Emmanuel; Sorel, Djeukoua Dimo Kamal; Jean-de-Dieu, Tamokou; Joseph, Tsemeugne; Sylvian, Kouamo; Doriane, Ngouanet; Rodolphe, Chouna Jean; Pepin, Nkeng-Efouet-Alango; Jules-Roger, Kuiate; Arnaud, Ngongang Ndjintchui; Lucas, Sondengam Beibam

2016-01-01

The in situ formed 4-oxo-4H-thieno[3,4-c]chromene-3-diazonium sulfate (5) in the coupling reactions involving the parent 2-aminothiophene (4) and various phenolic and arylamines' couplers, readily undergoes homocyclotrimerization at low temperature to afford in fairly good yield the first ever reported eighteen member ring heteroaromatic holigomer 6. Compound 6 was fully characterized by its elemental analysis, IR, UV-Vis, (1)H-NMR, (13)C-NMR and HRMS spectral data. The HMBC and HSQC techniques were used to ascertain the structural assignments. A comparative study on the antimicrobial and antioxidant activities of compounds 3, 4 and 6 was carried out to assess the SAR due to the transformations (from 3 to 6 via 4) on the tested compounds. It was found that compounds 6 and 4 were respectively the most active compounds against bacteria (MIC = 32-64 μg/ml) and yeasts (MIC = 16-64 μg/ml). Compound 6 also showed high radical-scavenging activities and ferric reducing power when compared with vitamin C and BHT used as reference antioxidants.

Synthesis, Characterization, Antimicrobial and Antioxidant Activities of The Homocyclotrimer Of 4-Oxo-4h-Thieno[3,4-C]Chromene-3-Diazonium Sulfate

Science.gov (United States)

Sopbue Fondjo, Emmanuel; Sorel, Djeukoua Dimo Kamal; Jean-de-Dieu, Tamokou; Joseph, Tsemeugne; Sylvian, Kouamo; Doriane, Ngouanet; Rodolphe, Chouna Jean; Pepin, Nkeng-Efouet-Alango; Jules-Roger, Kuiate; Arnaud, Ngongang Ndjintchui; Lucas, Sondengam Beibam

2016-01-01

The in situ formed 4-oxo-4H-thieno[3,4-c]chromene-3-diazonium sulfate (5) in the coupling reactions involving the parent 2-aminothiophene (4) and various phenolic and arylamines’ couplers, readily undergoes homocyclotrimerization at low temperature to afford in fairly good yield the first ever reported eighteen member ring heteroaromatic holigomer 6. Compound 6 was fully characterized by its elemental analysis, IR, UV-Vis, 1H-NMR, 13C-NMR and HRMS spectral data. The HMBC and HSQC techniques were used to ascertain the structural assignments. A comparative study on the antimicrobial and antioxidant activities of compounds 3, 4 and 6 was carried out to assess the SAR due to the transformations (from 3 to 6 via 4) on the tested compounds. It was found that compounds 6 and 4 were respectively the most active compounds against bacteria (MIC = 32-64 μg/ml) and yeasts (MIC = 16–64 μg/ml). Compound 6 also showed high radical-scavenging activities and ferric reducing power when compared with vitamin C and BHT used as reference antioxidants. PMID:27583034

Synthesis of 7-[α-(2-amino-[2-14C]thiazol-4-yl)-α-(Z)-methoxyimin oacetamido]-3-(1-methylpyrrolidinio)methyl-3-cephem-4-carboxylate hydrochloride ([14C]cefepime hydrochloride)

International Nuclear Information System (INIS)

Standridge, R.T.; Swigor, J.E.

1993-01-01

The title compound ([ 14 C]cefepime hydrochloride) was prepared as follows:- [ 14 C]Thiourea was condensed with ethyl 4-bromo-3-oxo-2-methoxyimino-acetate providing ethyl 2-(2-amino-4-[2- 14 C] thiazolyl)-2-methoxyi-minoacetate as the pure Z-isomer. Saponification gave the amino acid this was reacted with 1-hydroxybenzotriazole to give the activated ester. Condensation in situ with 7-amino-3-(1-methylpyrrolidinio) methyl-3-cephem-4-carboxylate yielded the product as the pure sulfate salt. Treatment of the sulfate salt with base provided the zwitterion isolated as the stable N-methyl-2-pyrrolidinone adduct. An aqueous solution of the adduct was converted to the crystalline title compound, [ 14 C]Cefepime hydrochloride hydrate, with hydrochloric acid/acetone. Radiochemical purity was 99.0% and specific activity, 34.2 μCi/mg. Overall yield from [ 14 C]thiourea was 18%. (Author)

In-situ TEM on (de)hydrogenation of Pd at 0.5-4.5 bar hydrogen pressure and 20-400°C.

Science.gov (United States)

Yokosawa, Tadahiro; Alan, Tuncay; Pandraud, Gregory; Dam, Bernard; Zandbergen, Henny

2012-01-01

We have developed a nanoreactor, sample holder and gas system for in-situ transmission electron microscopy (TEM) of hydrogen storage materials up to at least 4.5 bar. The MEMS-based nanoreactor has a microheater, two electron-transparent windows and a gas inlet and outlet. The holder contains various O-rings to have leak-tight connections with the nanoreactor. The system was tested with the (de)hydrogenation of Pd at pressures up to 4.5 bar. The Pd film consisted of islands being 15 nm thick and 50-500 nm wide. In electron diffraction mode we observed reproducibly a crystal lattice expansion and shrinkage owing to hydrogenation and dehydrogenation, respectively. In selected-area electron diffraction and bright/dark-field modes the (de)hydrogenation of individual Pd particles was followed. Some Pd islands are consistently hydrogenated faster than others. When thermally cycled, thermal hysteresis of about 10-16°C between hydrogen absorption and desorption was observed for hydrogen pressures of 0.5-4.5 bar. Experiments at 0.8 bar and 3.2 bar showed that the (de)hydrogenation temperature is not affected by the electron beam. This result shows that this is a fast method to investigate hydrogen storage materials with information at the nanometer scale. Copyright © 2011 Elsevier B.V. All rights reserved.

Fabrication and photocatalytic activity enhanced mechanism of direct Z-scheme g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4} photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Zhu, Bicheng [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Department of Science and Environmental Studies The Hong Kong Institute of Education, Tai Po, N.T., Hong Kong (China); Xia, Pengfei; Li, Yao [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Ho, Wingkei, E-mail: keithho@ied.edu.hk [Department of Science and Environmental Studies The Hong Kong Institute of Education, Tai Po, N.T., Hong Kong (China); Yu, Jiaguo, E-mail: jiaguoyu@yahoo.com [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2017-01-01

Highlights: • g-C{sub 3}N{sub 4} acted as a support for the in situ growth of β-Ag{sub 2}WO{sub 4}. • g-C{sub 3}N{sub 4} nanosheets inhibited the phase transformation of β-Ag{sub 2}WO{sub 4} to α-Ag{sub 2}WO{sub 4}. • g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4} exhibited a superior photocatalytic activity. • A direct Z-scheme photocatalytic mechanism could explain activity enhancement. - Abstract: Herein, a direct Z-scheme graphitic carbon nitride (g-C{sub 3}N{sub 4})/silver tungstate (Ag{sub 2}WO{sub 4}) photocatalyst was prepared by a facile in situ precipitation method using g-C{sub 3}N{sub 4} as a support and silver nitrate as a precursor. X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and elemental mapping demonstrated that β-Ag{sub 2}WO{sub 4} nanoparticles were evenly distributed on the surface of g-C{sub 3}N{sub 4} nanosheets, which acted as a support for the nucleation and growth of β-Ag{sub 2}WO{sub 4} and inhibited the phase transformation of metastable β-Ag{sub 2}WO{sub 4} to stable α-Ag{sub 2}WO{sub 4}. Photocatalytic experiments indicated that the g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4} nanocomposite photocatalyst displayed a better photocatalytic activity than pure g-C{sub 3}N{sub 4} and Ag{sub 2}WO{sub 4} toward the degradation of methyl orange. The enhanced photocatalytic performance of g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4} could be well explained by a direct Z-scheme photocatalytic mechanism. This mechanism was related to the efficient space separation of photogenerated electron–hole pairs and the great oxidation and reduction capabilities of the g-C{sub 3}N{sub 4}/Ag{sub 2}WO{sub 4} system. This work provided new insights into the design and fabrication of g-C{sub 3}N{sub 4}-based direct Z-scheme photocatalysts.

Phosphorylation-dephosphorylation process as a probable mechanism for the diurnal regulatory changes of phosphoenolpyruvate carboxylase in CAM plants.

Science.gov (United States)

Brulfert, J; Vidal, J; Le Marechal, P; Gadal, P; Queiroz, O; Kluge, M; Kruger, I

1986-04-14

Day and night forms of phosphoenolpyruvate carboxylase (EC 4.1.1.31) (PEPC) were extracted from leaves of the CAM plants Kalanchoe daigremontiana, K. tubiflora and K. blossfeldiana previously fed with [32P] labelled phosphate solution. A one-step immunochemical purification followed by SDS polyacrylamide gel electrophoresis and autoradiography showed that, in all species, the night form of the enzyme was phosphorylated and not the day form. Limited acid hydrolysis of the night form and two-dimensional separation identified predominantly labelled phosphoserine and phosphothreonine. In vitro addition of exogenous acid phosphatase (EC 3.1.3.2) to desalted night form-containing extracts resulted within 30 min in a shift in PEPC enzymic properties similar to the in vivo changes from night to day form. It is suggested that phosphorylation-dephosphorylation of the enzyme could be the primary in vivo process which might explain the observed rhythmicity of enzymic properties.

In situ hydrothermal synthesis of g-C{sub 3}N{sub 4}/TiO{sub 2} heterojunction photocatalysts with high specific surface area for Rhodamine B degradation

Energy Technology Data Exchange (ETDEWEB)

Hao, Ruirui [Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, Institute for Advanced Materials, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002 (China); Wang, Guohong, E-mail: wanggh2003@163.com [Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, Institute for Advanced Materials, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002 (China); Jiang, Chuanjia [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122, Wuhan, 430070 (China); Tang, Hua [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, 212013 (China); Xu, Qingchuan [Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, Institute for Advanced Materials, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002 (China)

2017-07-31

Highlights: • High surface area g-C{sub 3}N4/TiO{sub 2} is obtained by combined hydrothermal-calcination method. • HCl formation from Ti precursor changed the structural properties of the composite. • Composite exhibited visible light photocatalytic performance for RhB degradation. • A 3 g of melamine for 0.5 mL TiCl{sub 4} was found to be the optimum content. - Abstract: Semiconductor-based photocatalysis is a promising method for degradation of environmental pollutants, but the activity of most widely used photocatalysts such as titania (TiO{sub 2}) is still unsatisfactory under visible light. Herein, we synthesized a highly efficient visible-light-responsive heterojunction catalysts based on graphitic carbon nitride (g-C{sub 3}N{sub 4}) and TiO{sub 2}. The g-C{sub 3}N{sub 4}/TiO{sub 2} heterojunction composites with high specific surface area were prepared via in situ hydrothermal synthesis followed by calcination, using titanium tetrachloride (TiCl{sub 4}) and melamine as precursors. Interesting, HCl from the hydrolysis of TiCl{sub 4} served as the proton source to acidify the melamine. The g-C{sub 3}N{sub 4}/TiO{sub 2} heterojunction composites exhibited higher photocatalytic performance for decomposition of Rhodamine B (RhB) than pure g-C{sub 3}N{sub 4} or TiO{sub 2} under visible light irradiation. The high activity can be ascribed to the high specific surface area (up to 115.6 m{sup 2} g{sup −1}) of the g-C{sub 3}N{sub 4}/TiO{sub 2} composites and a synergistic heterojunction structure between TiO{sub 2} and g-C{sub 3}N{sub 4}. Moreover, the photocatalytic performances of the g-C{sub 3}N{sub 4}/TiO{sub 2} composites rely on the content of melamine in the synthesis precursors: with an optimum melamine content (3 g for 0.5 mL of TiCl{sub 4}), the sample showed the highest photocatalytic performance, which is superior to pure TiO{sub 2} and g-C{sub 3}N{sub 4} by a factor of 18.7 and 3.5, respectively. Active species trapping experiments revealed that

Measurements of in situ produced 14C in terrestrial rocks

International Nuclear Information System (INIS)

Yokoyama, Yusuke; Caffee, Marc W.; Southon, John R.; Nishiizumi, Kunihiko

2004-01-01

We developed and are testing a system for extracting in situ produced 14 C from quartz. 14 C is liberated from quartz matrix using step-wise heating during which time a spiked carrier gas consisting O 2 -CO-CO 2 -He is flowed through the high-temperature chamber continuously. The total 14 C background is reproducible and typically (2.3 ± 0.2) x 10 6 atoms, and the recovery is consistently greater than 90%. To validate the performance of the system and determine the blank level, we are using quartz samples taken from the Homestake mine (1600 m below the surface), South Dakota. To determine the 14 C release pattern and recovery, we used samples taken from the Transantarctic Mountains, Antarctica

Tissue-specific expression and post-translational modifications of plant- and bacterial-type phosphoenolpyruvate carboxylase isozymes of the castor oil plant, Ricinus communis L.

Science.gov (United States)

O’Leary, Brendan; Fedosejevs, Eric T.; Hill, Allyson T.; Bettridge, James; Park, Joonho; Rao, Srinath K.; Leach, Craig A.; Plaxton, William C.

2011-01-01

This study employs transcript profiling together with immunoblotting and co-immunopurification to assess the tissue-specific expression, protein:protein interactions, and post-translational modifications (PTMs) of plant- and bacterial-type phosphoenolpyruvate carboxylase (PEPC) isozymes (PTPC and BTPC, respectively) in the castor plant, Ricinus communis. Previous studies established that the Class-1 PEPC (PTPC homotetramer) of castor oil seeds (COS) is activated by phosphorylation at Ser-11 and inhibited by monoubiquitination at Lys-628 during endosperm development and germination, respectively. Elimination of photosynthate supply to developing COS by depodding caused the PTPC of the endosperm and cotyledon to be dephosphorylated, and then subsequently monoubiquitinated in vivo. PTPC monoubiquitination rather than phosphorylation is widespread throughout the castor plant and appears to be the predominant PTM of Class-1 PEPC that occurs in planta. The distinctive developmental patterns of PTPC phosphorylation versus monoubiquitination indicates that these two PTMs are mutually exclusive. By contrast, the BTPC: (i) is abundant in the inner integument, cotyledon, and endosperm of developing COS, but occurs at low levels in roots and cotyledons of germinated COS, (ii) shows a unique developmental pattern in leaves such that it is present in leaf buds and young expanding leaves, but undetectable in fully expanded leaves, and (iii) tightly interacts with co-expressed PTPC to form the novel and allosterically-desensitized Class-2 PEPC heteromeric complex. BTPC and thus Class-2 PEPC up-regulation appears to be a distinctive feature of rapidly growing and/or biosynthetically active tissues that require a large anaplerotic flux from phosphoenolpyruvate to replenish tricarboxylic acid cycle C-skeletons being withdrawn for anabolism. PMID:21841182

Hydrothermal Synthesis of Disulfide-Containing Uranyl Compounds. In Situ Ligand Synthesis versus Direct Assembly

Energy Technology Data Exchange (ETDEWEB)

Rowland, Clare E. [George Washington Univ., Washington, DC (United States); Belai, Nebebech [George Washington Univ., Washington, DC (United States); Knope, Karah E. [George Washington Univ., Washington, DC (United States); Cahill, Christopher L. [George Washington Univ., Washington, DC (United States)

2010-01-29

Three disulfide-containing uranyl compounds, [UO₂(C₇H₄O₂S)₃]·H₂O (1), [UO₂(C₇H₄O₂S)₂(C₇H₅O₂S)] (2), and [UO₂(C₇H₄O₂S)₄] (3) have been hydrothermally synthesized. Both in situ disulfide bond formation from 3- and 4-mercaptobenzoic acid (C₇H₅O₂S, MBA) to yield 3,3'- and 4,4'-dithiobisbenzoic acid (C₁₄H₈O₄S₂, DTBA) and direct assembly with the presynthesized dimeric ligands have been explored. While the starting materials 4-MBA and 4,4'-DTBA both yield 2 via in situ ligand synthesis and direct assembly, respectively, we observe the formation of 1 from the starting material 3-MBA via in situ ligand synthesis and of 3 from the direct assembly of the uranyl cation with 3,3'-DTBA. Concurrently with the synthesis of 1 and 2, we have observed the in situ formation of the crystalline dimeric organic species, 3,3'-DTBA, [(C₇H₅O₂S)₂] (4) and 4,4'-DTBA, [(C₇H₅O₂S)₂] (5). Herein we report the synthesis and crystallographic characterization of 1-5, as well as observations regarding the utility of product formation via direct assembly and in situ ligand synthesis.

In situ 119Sn Moessbauer spectroscopy used to study lithium insertion in c-Mg2Sn

International Nuclear Information System (INIS)

Aldon, L.; Ionica, C. M.; Lippens, P. E.; Larcher, D.; Tarascon, J.-M.; Olivier-Fourcade, J.; Jumas, J.-C.

2006-01-01

The electrochemical reactions of Li with c-Mg 2 Sn have been investigated by in situ Moessbauer spectroscopy of 119 Sn and X-ray diffraction. The lithiation transforms initially c-Mg 2 Sn part into Li x Mg 2 Sn alloy (x 2 MgSn ternary alloy. In situ Moessbauer spectroscopy provides valuable information on local environment of tin and swelling behavior and cracking of the particles during discharge and charge processes.

Fabrication of mullite-bonded porous SiC ceramics from multilayer-coated SiC particles through sol-gel and in-situ polymerization techniques

Science.gov (United States)

Ebrahimpour, Omid

In this work, mullite-bonded porous silicon carbide (SiC) ceramics were prepared via a reaction bonding technique with the assistance of a sol-gel technique or in-situ polymerization as well as a combination of these techniques. In a typical procedure, SiC particles were first coated by alumina using calcined powder and alumina sol via a sol-gel technique followed by drying and passing through a screen. Subsequently, they were coated with the desired amount of polyethylene via an in-situ polymerization technique in a slurry phase reactor using a Ziegler-Natta catalyst. Afterward, the coated powders were dried again and passed through a screen before being pressed into a rectangular mold to make a green body. During the heating process, the polyethylene was burnt out to form pores at a temperature of about 500°C. Increasing the temperature above 800°C led to the partial oxidation of SiC particles to silica. At higher temperatures (above 1400°C) derived silica reacted with alumina to form mullite, which bonds SiC particles together. The porous SiC specimens were characterized with various techniques. The first part of the project was devoted to investigating the oxidation of SiC particles using a Thermogravimetric analysis (TGA) apparatus. The effects of particle size (micro and nano) and oxidation temperature (910°C--1010°C) as well as the initial mass of SiC particles in TGA on the oxidation behaviour of SiC powders were evaluated. To illustrate the oxidation rate of SiC in the packed bed state, a new kinetic model, which takes into account all of the diffusion steps (bulk, inter and intra particle diffusion) and surface oxidation rate, was proposed. Furthermore, the oxidation of SiC particles was analyzed by the X-ray Diffraction (XRD) technique. The effect of different alumina sources (calcined Al2O 3, alumina sol or a combination of the two) on the mechanical, physical, and crystalline structure of mullite-bonded porous SiC ceramics was studied in the

A New Design of In Situ Ti(C,N) Reinforced Composite Coatings and Their Microstructures, Interfaces, and Wear Resistances.

Science.gov (United States)

Wang, Mingliang; Cui, Hongzhi; Wei, Na; Ding, Lei; Zhang, Xinjie; Zhao, Yong; Wang, Canming; Song, Qiang

2018-01-31

Here, a unique combination of a novel carbon-nitrogen source (g-C 3 N 4 ) with different mole ratios of Ti/g-C 3 N 4 has been utilized to fabricate iron matrix composite coatings by a synchronized powder feeding plasma transferred arc (PTA) cladding technology. The results show that submicron Ti(C,N) particles are successfully fabricated in situ on a Q235 low carbon steel substrate to reinforce the iron matrix composite coatings and exhibit dense microstructures and good metallurgical bonding between the coating and the substrate. The microstructure of the coating consists of an α-Fe matrix and Ti(C,N) particles when the mole ratio of Ti/g-C 3 N 4 is no more than 5:1. The microhardness and wear resistance of the coating gradually improve with increasing abundance of the in-situ-synthesized Ti(C,N) particles. Interestingly, for a Ti/g-C 3 N 4 mole ratio of 6:1, a fine lamellar eutectic Laves phase (Fe 2 Ti) appears, and this phase further improves the microhardness and wear resistance of the coating. The microhardness of the coating is 3.5 times greater than that of the Q235 substrate, and the wear resistance is enhanced 7.66 times over that of the substrate. The Ti(C,N)/Fe 2 Ti and Fe 2 Ti/α-Fe interfaces are very clean, and the crystallographic orientation relationships between the phases are analyzed by high-resolution transmission electron microscopy (HRTEM) and an edge-to-edge matching model. The theoretical predictions and the experimental results are in good agreement. Furthermore, based on the present study, for the solidification process near equilibrium, smaller interatomic spacing misfits and interplanar spacing d-value mismatches contribute to the formation of crystallographic orientation relationships between phases during the PTA cladding process. The existence of orientation relationships is beneficial for improving the properties of the coatings. This work not only expands the application fields of g-C 3 N 4 but also provides a new idea for the

Desired crystal oriented LiFePO4 nanoplatelets in situ anchored on a graphene cross-linked conductive network for fast lithium storage.

Science.gov (United States)

Wang, Bo; Liu, Anmin; Abdulla, Wael Al; Wang, Dianlong; Zhao, X S

2015-05-21

Electron transfer and lithium ion diffusion rates are the key factors limiting the lithium ion storage in anisotropic LiFePO4 electrodes. In this work, we employed a facile solvothermal method to synthesize a "platelet-on-sheet" LiFePO4/graphene composite (LFP@GNs), which is LiFePO4 nanoplatelets in situ grown on graphene sheets with highly oriented (010) facets of LiFePO4 crystals. Such a two-phase contact mode with graphene sheets cross-linked to form a three-dimensional porous network is favourable for both fast lithium ion and electron transports. As a result, the designed LFP@GNs displayed a high rate capability (∼56 mA h g(-1) at 60 C) and long life cycling stability (∼87% capacity retention over 1000 cycles at 10 C). For comparison purposes, samples ex situ modified with graphene (LFP/GNs) as well as pure LiFePO4 platelets (LFP) were also prepared and investigated. More importantly, the obtained LFP@GNs can be used as a basic unit for constructing more complex structures to further improve electrochemical performance, such as coating the exposed LFP surface with a thin layer of carbon to build a C@LFP@GN composite to further enhance its cycling stability (∼98% capacity retention over 1000 cycles at 10 C).

O-GlcNAcylation mediates the control of cytosolic phosphoenolpyruvate carboxykinase activity via Pgc1α.

Directory of Open Access Journals (Sweden)

Pedro Latorre

Full Text Available PGC1α is a coactivator of many transcription factors and cytosolic phosphoenolpyruvate carboxykinase (PCK1 is a key enzyme for gluconeogenesis. PGC1α interacts with the transcription factor PPARγ to stimulate PCK1 expression and thus de novo glucose synthesis. These proteins are not only important for central energy metabolism but also for supplying intermediates for other metabolic pathways, including lipidogenesis and protein synthesis and might therefore be important factors in the ethiopathogenesis of metabolic disorders like diabetes but also in other pathologies like cancer. Since polymorphisms in these proteins have been related to some phenotypic traits in animals like pigs and PGC1α G482S polymorphism increases fat deposition in humans, we have investigated the molecular basis of such effects focusing on a commonly studied polymorphism in pig Pgc1α, which changes a cysteine at position 430 (WT of the protein to a serine (C430S. Biochemical analyses show that Pgc1α WT stimulates higher expression of human PCK1 in HEK293T and HepG2 cells. Paradoxically, Pgc1α WT is less stable than Pgc1α p.C430S in HEK293T cells. However, the study of different post-translational modifications shows a higher O-GlcNAcylation level of Pgc1α p.C430S. This higher O-GlcNAcylation level significantly decreases the interaction between Pgc1α and PPARγ demonstrating the importance of post-translational glycosylation of PGC1α in the regulation of PCK1 activity. This, furthermore, could explain at least in part the observed epistatic effects between PGC1α and PCK1 in pigs.

In situ chemical oxidative polymerization preparation of poly(3,4-ethylenedioxythiophene)/graphene nanocomposites with enhanced thermoelectric performance.

Science.gov (United States)

Xu, Kongli; Chen, Guangming; Qiu, Dong

2015-05-01

Three different in situ chemical oxidative polymerization routes, that is, (A) spin-coating and subsequent liquid layer polymerization, (B) spin-coating followed by vapor phase polymerization, and (C) in situ polymerization and then post-treatment by immersion in ethylene glycol (EG), have been developed to achieve poly(3,4-ethylenedioxythiophene)/reduced graphene oxide (PEDOT/rGO) nanocomposites. As demonstrated by scanning electron microscopic and energy-dispersive X-ray spectroscopic techniques, PEDOT has been successfully coated on the surface of the rGO nanosheets by each of the three preparation routes. Importantly, all of the nanocomposites display a greatly enhanced thermoelectric performance (power factors) relative to those of the corresponding neat PEDOT. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of steel matrix composites locally reinforced with different ratios of TiC/TiB2 particulates using SHS reactions of Ni-Ti-B4C and Ni-Ti-B4C-C systems during casting

International Nuclear Information System (INIS)

Yang Yafeng; Wang Huiyuan; Liang Yunhong; Zhao Ruyi; Jiang Qichuan

2007-01-01

Steel matrix composites locally reinforced with different molar ratios of in situ TiC/TiB 2 particulates (2:1, 1:1 and 1:2, respectively) have been fabricated successfully utilizing the self-propagating high-temperature synthesis (SHS) reactions of Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems during casting. Differential thermal analysis (DTA) and X-ray diffraction (XRD) results reveal that the exothermic reactions of the Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems proceed in such a way that Ni initially reacts with B 4 C and Ti to form Ni 2 B and Ti 2 Ni compounds, respectively, with heat evolution at 1037 deg. C; Subsequently, the external heat and the evolved heat from these exothermic reactions promote the reactions forming TiC and TiB 2 at 1133 deg. C. In the composites reinforced with 1:2 molar ratio of TiC/TiB 2 , almost all TiB 2 grains have clubbed structures, while TiC grains exhibit near-spherical morphologies. Furthermore, TiB 2 grain sizes decrease, with the increase of TiC content. In particular, in the composites reinforced with 2:1 molar ratio of TiC/TiB 2 , it is difficult to find the clubbed TiB 2 grains. Macro-pores and blowholes are absent in the local reinforcing region of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 , while a few macro-pores can be observed in the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . Moreover, the densities of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 are higher than that of the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . The composite reinforced with 1:2 molar ratio of TiC/TiB 2 has the highest hardness and the best wear resistance

In-situ synchrotron PXRD study of spinel LiMn2O4 formation

DEFF Research Database (Denmark)

Birgisson, Steinar; Jensen, Kirsten Marie Ørnsbjerg; Christiansen, Troels Lindahl

structural properties for the reaction being studied. Normally the reactions are started by heating and a constant temperature is kept throughout the experiment. In this study the hydrothermal reaction previously shown to produce spinel LiMn2O4 nanoparticles is studied in-situ to learn more about the phase......O4, depending on the initial concentration if Li-ions. An impurity phase, identified as Mn3O4, is also detected in different concentrations depending on reaction time and temperature. We have developed an experimental technique for in-situ measurements of solvothermal reactions under sub...... in the in-situ measurements it gives a unique opportunity to study reaction kinetics and thermodynamic quantities of the reactions. A temperature study of the reaction has been conducted to see how the formation rate and particle growth is affected by temperature while the precursor concentration is kept...

Changes in the isozymic pattern of phosphoenolpyruvate : An early step in photoperiodic control of crassulacean acid metabolism level.

Science.gov (United States)

Brulfert, J; Arrabaça, M C; Guerrier, D; Queiroz, O

1979-01-01

Two major isofunctional forms of phosphoenolpyruvate carboxylase (EC 4.1.1.31) have been separated from the leaves of Kalanchoe blossfeldiana Poelln. Tom Thumb by acrylamide gel electrophoresis and diethylaminoethyl cellulose techniques: one of the forms prevails under long-day treatment (low crassulacean acid metabolism level), the other develops under short-day treatment (high Crassulacean acid metabolism level). Molecular weights are significantly different: 175·10(3) and 186·10(3), respectively. These results indicate that two populations of phosphoenolyruvate carboxylase are present in the plant, one of which is responsible for Crassulacean acid metabolism activity under the control of photoperiod.The Crassulacean acid metabolism appears to depend on the same endogenous clock that governs other photoperiodically controlled events (e.g. flowering). The metabolic and energetic significance of this feature is discussed. It is suggested that modification in isozymic composition could be an early step in the response to photoperiodism at the metabolic level.

Enhanced J c property in nano-SiC doped thin MgB2/Fe wires by a modified in situ PIT process

International Nuclear Information System (INIS)

Jiang, C.H.; Nakane, T.; Hatakeyama, H.; Kumakura, H.

2005-01-01

A modified in situ PIT process, which included a short time pre-annealing and intermediate drawing step in the conventional in situ PIT process, was employed to fabricate thin round MgB 2 /Fe wires from MgH 2 and B powders. The pores and cracks resulted from the MgH 2 decomposition during the pre-annealing were effectively eliminated by the intermediate drawing step, which subsequently increased the core density and J c property of final heat treated wires. A higher reduction rate after the pre-annealing led to a larger enhancement in J c within this study. The reproducibility of our new process on the J c improvement in MgB 2 wires was confirmed in two series of wires doped with 5 mol% or 10 mol% nano-SiC particles separately

Determination of gluconeogenesis in vivo with 14C-labeled substrates

International Nuclear Information System (INIS)

Katz, J.

1985-01-01

A mitochondrial model of gluconeogenesis and the tricarboxylic acid cycle, where pyruvate is metabolized via pyruvate carboxylase and pyruvate dehydrogenase, and pyruvate kinase is examined. The effect of the rate of tricarboxylic acid flux and the rates of the three reactions of pyruvate metabolism on the labeling patterns from [ 14 C]pyruvate and [ 14 C]acetate are analyzed. Expressions describing the specific radioactivities and 14 C distribution in glucose as a function of these rates are derived. Specific radioactivities and isotopic patterns depend markedly on the ratio of the rates of pyruvate carboxylation and decarboxylation to the rate of citrate synthesis, but the effect of phosphoenolpyruvate hydrolysis is minor. The effects of these rates on 1) specific radioactivity of phosphoenolpyruvate, 2) labeling pattern in glucose, and 3) contribution of pyruvate, acetyl-coenzyme A, and CO 2 to glucose carbon are illustrated. To determine the contribution of lactate or alanine to gluconeogenesis, experiments with two compounds labeled in different carbons are required. Methods in current use to correct for the dilution of 14 C in gluconeogenesis from [ 14 C]pyruvate are shown to be erroneous. The experimental design and techniques to determine gluconeogenesis from 14 C-labeled precursors are presented and illustrated with numerical examples

In-situ anatase phase stabilization of titania photocatalyst by sintering in presence of Zr4+ organic salts

Science.gov (United States)

Strini, Alberto; Sanson, Alessandra; Mercadelli, Elisa; Bendoni, Riccardo; Marelli, Marcello; Dal Santo, Vladimiro; Schiavi, Luca

2015-08-01

The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degussa P25) was obtained by sintering the catalyst powder in presence of Zr4+ organic salts. This approach allows the doping of an already-formed nanocrystalline photocatalyst instead of introducing the dopant in the crystal lattice during the catalyst synthesis. The procedure was demonstrated by the production of thick ceramic layers using the screen printing technique. This new method allows to easily stabilize the anatase phase 200 °C higher than the undoped P25 maintaining the same photocatalytic activity. The process was studied using specifically formulated screen-printing inks added with Zr4+ organic salt at 1% and 2% Zr/Ti molar ratio. The anatase phase stability was investigated in the 500-900 °C temperature range analysing the resulting catalysts with XRD, TEM and (S)TEM-EDS. The catalytic activity of the screen-printed layers was assessed by measuring the degradation of toluene in air at ambient concentration (500 nmol m-3) and low UV-A irradiance (180 μW cm-2). The described in-situ stabilization method could be potentially applied to any deposition process involving already formed anatase photocatalyst, allowing higher sintering temperature and then an improved mechanical stability of the active layers without photocatalytic activity degradation.

The crystal structure of paramagnetic copper(ii) oxalate (CuC2O4):

DEFF Research Database (Denmark)

Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel

2014-01-01

Synthetic copper(ii) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(ii) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have...... the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(ii) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar....... The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns...

In-situ anatase phase stabilization of titania photocatalyst by sintering in presence of Zr{sup 4+} organic salts

Energy Technology Data Exchange (ETDEWEB)

Strini, Alberto, E-mail: alberto.strini@itc.cnr.it [Istituto per le Tecnologie della Costruzione (ITC-CNR), via Lombardia, 49, I-20098 San Giuliano Milanese (MI) (Italy); Sanson, Alessandra; Mercadelli, Elisa [Istituto di Scienza e Tecnologia dei Materiali Ceramici (ISTEC-CNR), via Granarolo, 64, I-48018 Faenza (RA) (Italy); Bendoni, Riccardo [Istituto di Scienza e Tecnologia dei Materiali Ceramici (ISTEC-CNR), via Granarolo, 64, I-48018 Faenza (RA) (Italy); Dipartimento di Scienze e Tecnologie Chimiche e Centro NAST - Università di Roma Tor Vergata, via della Ricerca Scientifica, I-00133 Roma (Italy); Marelli, Marcello; Dal Santo, Vladimiro [CNR–Istituto di Scienze e Tecnologie Molecolari, via Golgi, 19, I-20133 Milano (Italy); Schiavi, Luca [Istituto per le Tecnologie della Costruzione (ITC-CNR), via Lombardia, 49, I-20098 San Giuliano Milanese (MI) (Italy)

2015-08-30

Graphical abstract: - Highlights: • Existing commercial (P25) anatase was stabilized in-situ with Zr(IV) doping. • Highly active catalytic layers were obtained by screen-printing. • Increased thermal stability was demonstrated up to 200 °C without activity loss. • Enhanced activity was obtained because of the Zr(IV) doping. • Zirconium diffusion was assessed by STEM-EDS analysis. - Abstract: The direct in-situ stabilization of an anatase-based nanocrystalline photocatalyst (Degussa P25) was obtained by sintering the catalyst powder in presence of Zr{sup 4+} organic salts. This approach allows the doping of an already-formed nanocrystalline photocatalyst instead of introducing the dopant in the crystal lattice during the catalyst synthesis. The procedure was demonstrated by the production of thick ceramic layers using the screen printing technique. This new method allows to easily stabilize the anatase phase 200 °C higher than the undoped P25 maintaining the same photocatalytic activity. The process was studied using specifically formulated screen-printing inks added with Zr{sup 4+} organic salt at 1% and 2% Zr/Ti molar ratio. The anatase phase stability was investigated in the 500–900 °C temperature range analysing the resulting catalysts with XRD, TEM and (S)TEM-EDS. The catalytic activity of the screen-printed layers was assessed by measuring the degradation of toluene in air at ambient concentration (500 nmol m{sup −3}) and low UV-A irradiance (180 μW cm{sup −2}). The described in-situ stabilization method could be potentially applied to any deposition process involving already formed anatase photocatalyst, allowing higher sintering temperature and then an improved mechanical stability of the active layers without photocatalytic activity degradation.

In situ x-ray diffraction studies of three-dimensional C60 polymers

International Nuclear Information System (INIS)

Wood, R A; Lewis, M H; Bennington, S M; Cain, M G; Kitamura, N; Fukumi, A K

2002-01-01

In situ investigations into the P/T field of C 60 fullerene were performed using energy-dispersive x-ray diffraction techniques. Isobars were obtained at 11 and 9 GPa accompanied by isotherms at 750 and 800 K with pressure reaching 13 GPa. The P/T history and pressure isotropy were investigated with the aim of optimizing conditions for 3D polymer formation. Confirmation of the formation of 3D polymers was performed in situ; however, the reclaimed sample did not exhibit the expected high hardness value, due to depolymerization on pressure release. Isotropy in the pressure field promoted formation and retention of the face-centred-cubic structure

In-situ radiation measurements of the C1 and C2 waste storage tank vault

International Nuclear Information System (INIS)

Yong, L.K.; Womble, P.C.; Weems, L.D.

1996-09-01

In August of 1996, the Applied Radiation Measurements Department (ARMD) of the Waste Management and Remedial Action Division (WMRAD) at Oak Ridge National Laboratory (ORNL) was tasked with characterizing the radiation fields in the C 1 and C 2 Liquid Low Level Waste (LLLW) tank vault located at ORNL. These in-situ measurements were made to provide data for evaluating the potential radiological conditions for personnel working in or around the vault during future planned activities. This report describes the locations where measurements were made, the types of radiation detection instruments used, the methods employed, the problems encountered and resolved, and discusses the results obtained

Simulated plasma facing component measurements for an in situ surface diagnostic on Alcator C-Moda)

Science.gov (United States)

Hartwig, Z. S.; Whyte, D. G.

2010-10-01

The ideal in situ plasma facing component (PFC) diagnostic for magnetic fusion devices would perform surface element and isotope composition measurements on a shot-to-shot (˜10 min) time scale with ˜1 μm depth and ˜1 cm spatial resolution over large areas of PFCs. To this end, the experimental adaptation of the customary laboratory surface diagnostic—nuclear scattering of MeV ions—to the Alcator C-Mod tokamak is being guided by ACRONYM, a Geant4 synthetic diagnostic. The diagnostic technique and ACRONYM are described, and synthetic measurements of film thickness for boron-coated PFCs are presented.

Despite phylogenetic effects, C3-C4 lineages bridge the ecological gap to C4 photosynthesis.

Science.gov (United States)

Lundgren, Marjorie R; Christin, Pascal-Antoine

2017-01-01

C 4 photosynthesis is a physiological innovation involving several anatomical and biochemical components that emerged recurrently in flowering plants. This complex trait evolved via a series of physiological intermediates, broadly termed 'C 3 -C 4 ', which have been widely studied to understand C 4 origins. While this research program has focused on biochemistry, physiology, and anatomy, the ecology of these intermediates remains largely unexplored. Here, we use global occurrence data and local habitat descriptions to characterize the niches of multiple C 3 -C 4 lineages, as well as their close C 3 and C 4 relatives. While C 3 -C 4 taxa tend to occur in warm climates, their abiotic niches are spread along other dimensions, making it impossible to define a universal C 3 -C 4 niche. Phylogeny-based comparisons suggest that, despite shifts associated with photosynthetic types, the precipitation component of the C 3 -C 4 niche is particularly lineage specific, being highly correlated with that of closely related C 3 and C 4 taxa. Our large-scale analyses suggest that C 3 -C 4 lineages converged toward warm habitats, which may have facilitated the transition to C 4 photosynthesis, effectively bridging the ecological gap between C 3 and C 4 plants. The intermediates retained some precipitation aspects of their C 3 ancestors' habitat, and likely transmitted them to their C 4 descendants, contributing to the diversity among C 4 lineages seen today. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

In situ characterization of the decomposition behavior of Mg(BH4)2 by X-ray Raman scattering spectroscopy.

Science.gov (United States)

Sahle, Christoph J; Kujawski, Simon; Remhof, Arndt; Yan, Yigang; Stadie, Nicholas P; Al-Zein, Ali; Tolan, Metin; Huotari, Simo; Krisch, Michael; Sternemann, Christian

2016-02-21

We present an in situ study of the thermal decomposition of Mg(BH4)2 in a hydrogen atmosphere of up to 4 bar and up to 500 °C using X-ray Raman scattering spectroscopy at the boron K-edge and the magnesium L2,3-edges. The combination of the fingerprinting analysis of both edges yields detailed quantitative information on the reaction products during decomposition, an issue of crucial importance in determining whether Mg(BH4)2 can be used as a next-generation hydrogen storage material. This work reveals the formation of reaction intermediate(s) at 300 °C, accompanied by a significant hydrogen release without the occurrence of stable boron compounds such as amorphous boron or MgB12H12. At temperatures between 300 °C and 400 °C, further hydrogen release proceeds via the formation of higher boranes and crystalline MgH2. Above 400 °C, decomposition into the constituting elements takes place. Therefore, at moderate temperatures, Mg(BH4)2 is shown to be a promising high-density hydrogen storage material with great potential for reversible energy storage applications.

Grout performance in support of in situ grouting of the TH4 tank sludge

Energy Technology Data Exchange (ETDEWEB)

Hunt, R.D.; Kauschinger, J.L.; Spence, R.D.

1999-04-01

The cold demonstration test proved that less water was required to pump the in situ grout formulation than had been previously tested in the laboratory. The previous in situ grout formulation was restandardized with the same relative amounts of dry blend ingredients, albeit adding a fluidized admixture, but specifying less water for the slurry mix that must by pumped through the nozzles at high pressure. Also, the target GAAT tank for demonstrating this is situ grouting technique has been shifted to Tank TH4. A chemical surrogate sludge for TH4 was developed and tested in the laboratory, meeting expectations for leach resistance and strenght at 35 wt % sludge loading. It addition, a sample of hot TH4 sludge was also tested at 35 wt % sludge loading and proved to have superior strength and leach resistance compared with the surrogate test.

Photosynthesis in Flaveria brownii, a C(4)-Like Species: Leaf Anatomy, Characteristics of CO(2) Exchange, Compartmentation of Photosynthetic Enzymes, and Metabolism of CO(2).

Science.gov (United States)

Cheng, S H; Moore, B D; Edwards, G E; Ku, M S

1988-08-01

Light microscopic examination of leaf cross-sections showed that Flaveria brownii A. M. Powell exhibits Kranz anatomy, in which distinct, chloroplast-containing bundle sheath cells are surrounded by two types of mesophyll cells. Smaller mesophyll cells containing many chloroplasts are arranged around the bundle sheath cells. Larger, spongy mesophyll cells, having fewer chloroplasts, are located between the smaller mesophyll cells and the epidermis. F. brownii has very low CO(2) compensation points at different O(2) levels, which is typical of C(4) plants, yet it does show about 4% inhibition of net photosynthesis by 21% O(2) at 30 degrees C. Protoplasts of the three photosynthetic leaf cell types were isolated according to relative differences in their buoyant densities. On a chlorophyll basis, the activities of phosphoenolpyruvate carboxylase and pyruvate, Pi dikinase (carboxylation phase of C(4) pathway) were highest in the larger mesophyll protoplasts, intermediate in the smaller mesophyll protoplasts, and lowest, but still present, in the bundle sheath protoplasts. In contrast, activities of ribulose 1,5-bisphosphate carboxylase, other C(3) cycle enzymes, and NADP-malic enzyme showed a reverse gradation, although there were significant activities of these enzymes in mesophyll cells. As indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the banding pattern of certain polypeptides of the total soluble proteins from the three cell types also supported the distribution pattern obtained by activity assays of these enzymes. Analysis of initial (14)C products in whole leaves and extrapolation of pulse-labeling curves to zero time indicated that about 80% of the CO(2) is fixed into C(4) acids (malate and aspartate), whereas about 20% of the CO(2) directly enters the C(3) cycle. This is consistent with the high activity of enzymes for CO(2) fixation by the C(4) pathway and the substantial activity of enzymes of the C(3) cycle in the mesophyll cells

In-situ synthesis of monodisperse micro-nanospherical LiFePO4/carbon cathode composites for lithium-ion batteries

Science.gov (United States)

Gong, Hao; Xue, Hairong; Wang, Tao; He, Jianping

2016-06-01

The LiFePO4 is recognized as the promising cathode material, due to its high specific capacity, excellent, structural stability and environmental benignity. However, it is blamed for the low tap density and poor rate performance when served as the cathode materials for a long time. Here, the microspheric LiFePO4/C composites are successfully synthesized through a one-step in-situ solvothermal method combined with carbothermic reduction. These LiFePO4/C microspheres are assembled by LiFePO4 nanoparticles (∼100 nm) and uniformly coated by the carbon, which show a narrow diameter distribution of 4 μm. As a cathode material for lithium ion batteries, the LiFePO4/C composites can deliver an initiate charge capacity of 155 mAh g-1 and retain 90% of initial capacity after 200 cycles at 0.1 C. When cycled at high current densities up to 20 C, it shows a discharge capacity of ∼60 mAh g-1, exhibiting superior rate performance. The significantly improved electrochemical performance of LiFePO4/C composites material can be attributed to its special micro-nano hierarchical structure. Microspheric LiFePO4/C composites exhibit a high tap density about 1.3 g cm-3. What's more, the well-coated carbon insures the high electrical conductivity and the nano-sized LiFePO4/C particles shorten lithium ion transport, thus exhibiting the high specific capacity, high cycling stability and good rate performance.

Reticulate leaves and stunted roots are independent phenotypes pointing at opposite roles of the phosphoenolpyruvate/phosphate translocator defective in cue1 in the plastids of both organs

Czech Academy of Sciences Publication Activity Database

Staehr, P.; Loettgert, T.; Christmann, A.; Krueger, S.; Rosar, Ch.; Rolčík, Jakub; Novák, Ondřej; Strnad, Miroslav; Bell, K.; Weber, A.P.M.; Fluegge, U-I.; Haeusler, R.E.

2014-01-01

Roč. 5, APR 2014 (2014) ISSN 1664-462X R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : secondary metabolism * phosphate translocator * phosphoenolpyruvate Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.948, year: 2014

Structural and Electrochemical Characterization of Pure LiFePO4 and Nanocomposite C-LiFePO4 Cathodes for Lithium Ion Rechargeable Batteries

Directory of Open Access Journals (Sweden)

Arun Kumar

2009-01-01

Full Text Available Pure lithium iron phosphate (LiFePO4 and carbon-coated LiFePO4 (C-LiFePO4 cathode materials were synthesized for Li-ion batteries. Structural and electrochemical properties of these materials were compared. X-ray diffraction revealed orthorhombic olivine structure. Micro-Raman scattering analysis indicates amorphous carbon, and TEM micrographs show carbon coating on LiFePO4 particles. Ex situ Raman spectrum of C-LiFePO4 at various stages of charging and discharging showed reversibility upon electrochemical cycling. The cyclic voltammograms of LiFePO4 and C-LiFePO4 showed only a pair of peaks corresponding to the anodic and cathodic reactions. The first discharge capacities were 63, 43, and 13 mAh/g for C/5, C/3, and C/2, respectively for LiFePO4 where as in case of C-LiFePO4 that were 163, 144, 118, and 70 mAh/g for C/5, C/3, C/2, and 1C, respectively. The capacity retention of pure LiFePO4 was 69% after 25 cycles where as that of C-LiFePO4 was around 97% after 50 cycles. These results indicate that the capacity and the rate capability improved significantly upon carbon coating.

Understanding the degree of condensation of phenolic and etherified C-9 units of in situ lignins.

Science.gov (United States)

Nanayakkara, Bernadette; Manley-Harris, Merilyn; Suckling, Ian D

2011-12-14

A novel approach for the quantification of the degree of condensation at the C(5) position of etherified and phenolic phenylpropane (C-9) units of in situ lignin is described. This is achieved by degrading unmethylated and methylated wood by thioacidolysis and analyzing the resultant product mixtures by quantitative (31)P NMR spectroscopy. Applying this new method to compression wood and normal wood from Pinus radiata showed that, whereas 41-47% of etherified guaiacyl C-9 units are condensed at the C(5) position, almost all phenolic guaiacyl C-9 units exist as uncondensed moieties. Analysis of milled wood lignin (MWL) isolated from the same wood by (31)P NMR spectroscopy before and after thioacidolysis showed that the phenolic guaiacyl C-9 units were more condensed than those in the in situ lignin. This is likely due to partial cleavage of the more condensed etherified linkages during the lignin isolation, leading to a relative increase in condensed phenolic guaiacyl C-9 units.

Elastic properties of nanolaminar Cr_2AlC films and beams determined by in-situ scanning electron microscope bending tests

International Nuclear Information System (INIS)

Grieseler, Rolf; Theska, Felix; Stürzel, Thomas; Hähnlein, Bernd; Stubenrauch, Mike; Hopfeld, Marcus; Kups, Thomas; Pezoldt, Jörg; Schaaf, Peter

2016-01-01

The mechanical properties of Cr_2AlC MAX phase structures were investigated by in-situ bending tests. Freestanding structures such as cantilevers and doubly clamped beams of Cr_2AlC were produced. The structures exhibit a Young's modulus of 184 GPa which is close to the value obtained by vibrational measurements. The in-situ bending test allows the determination of the mechanical properties with a lower variance of the measurement results compared to the vibrational measurement. The results are a good starting point for the development of microelectromechanical structures based on MAX phases. - Highlights: • Cr_2AlC were produced by deposition multilayers and subsequent rapid annealing. • Freestanding doubly clamped beams and cantilevers of Cr_2AlC were prepared. • A finite elements model was implemented showing the displacement of the structure. • In-situ bending test at doubly clamped beams and cantilevers were performed. • An in-situ bending test is a valid approach to determine mechanical properties.

Staphylococcal phosphoenolpyruvate-dependent phosphotransferase system: purification and characterization of the mannitol-specific enzyme III/sup mtl/ of Staphylococcus aureus and Staphylococcus carnosus and homology with the enzyme II/sup mtl/ of Escherichia coli

International Nuclear Information System (INIS)

Reiche, B.; Frank, R.; Deutscher, J.; Meyer, N.; Hengstenberg, W.

1988-01-01

Enzyme III/sup mtl/ is part of the mannitol phosphotransferase system of Staphylococcus aureus and Staphylococcus carnosus and is phosphorylated by phosphoenolpyruvate in a reaction sequence requiring enzyme I (phosphoenolpyruvate-protein phosphotransferase) and the histidine-containing protein HPr. In this paper, the authors report the isolation of III/sup mtl/ from both S. aureus and S. carnosus and the characterization of the active center. After phosphorylation of III/sup mtl/ with [ 32 P]PEP, enzyme I, and HPr, the phosphorylated protein was cleaved with endoproteinase GLu(C). The amino acid sequence of the S. aureus peptide carrying the phosphoryl group was found to be Gln-Val-Val-Ser-Thr-Phe-Met-Gly-Asn-Gly-Leu-Ala-Ile-Pro-His-Gly-Thr-Asp-Asp. The corresponding peptide from S. carnosus shows an equal sequence except that the first residue is Ala instead of Gln. These peptides both contain a single histidyl residue which they assume to carry the phosphoryl group. All proteins of the PTS so far investigated indeed carry the phosphoryl group attached to a histidyl residue. According to sodium dodecyl sulfate gels, the molecular weight of the III/sup mtl/ proteins was found to be 15,000. They have also determined the N-terminal sequence of both proteins. Comparison of the III/sup mtl/ peptide sequences and the C-terminal part of the enzyme II/sup mtl/ of Escherichia coli reveals considerable sequence homology, which supports the suggestion that II/sup mtl/ of E. coli is a fusion protein of a soluble III protein with a membrane-bound enzyme II

In-Situ Measurement of Vitamin C Content in Commercial Tablet Products by Terahertz Time-Domain

Science.gov (United States)

Kang, JuHee; Song, Jeonghun; Jung, Tae Sub; Kwak, Kyungwon; Chun, Hyang Sook

2018-04-01

Terahertz time-domain spectroscopy (THz-TDS) was applied to investigate the feasibility of in-situ measuring vitamin C content in commercial tablet products without any pretreatments. Characteristic absorption peaks of vitamin C were analyzed with quantum mechanical calculation to reveal the molecular origin of them. The peak appearing at 1.08 THz was then selected and tested for its suitability as a fingerprint signal for analyzing the vitamin C content in dietary supplement tablets. There are a couple of factors influencing THz absorbance other than concentration. Among those, the effects of tablet thickness and types of excipients in the tablet products were found to be significant, and were corrected with the calibration curve to determine vitamin C concentration in tablet forms. Furthermore, commercial tablet products in the market were analyzed using THz-TDS and the measured vitamin C contents were in good agreement with those determined using a reference method (high-performance liquid chromatography). Thus, our results suggest that THz-TDS can be used for the in-situ analysis of vitamin C in commercial tablet products.

Analysis of mechanical properties of N2in situ doped polycrystalline 3C-SiC thin films by chemical vapor deposition using single-precursor hexamethyildisilane

International Nuclear Information System (INIS)

Kim, Kang-San; Han, Ki-Bong; Chung, Gwiy-Sang

2010-01-01

This paper describes the mechanical properties of poly (polycrystalline) 3C-SiC thin films with N 2 in situ doping. In this work, in situ doped poly 3C-SiC film was deposited by using the atmospheric pressure chemical vapor deposition (APCVD) method at 1200 deg. C using single-precursor hexamethyildisilane: Si 2 (CH 3 ) 6 (HMDS) as Si and C precursors, and 0∼100 sccm N 2 as the dopant source gas. The mechanical properties of doped poly 3C-SiC thin films were measured by nano-indentation. Young's modulus and hardness were measured to be 285 and 35 GPa at 0 sccm N 2 , respectively. Young's modulus and hardness decreased with increasing N 2 flow rate. Surface morphology was evaluated by atomic force microscopy (AFM) according to N 2 flow rate.

Al-TiC in situ composite coating fabricated by low power pulsed laser cladding on AZ91D magnesium alloy

Science.gov (United States)

Yang, Liuqing; Li, Zhiyong; Zhang, Yingqiao; Wei, Shouzheng; Liu, Fuqiang

2018-03-01

Al + (Ti + B4C) composite coating was cladded on AZ91D magnesium alloy by a low power pulsed Nd-YAG laser. The Ti+B4C mixed powder is with the ratio of Ti: B4C = 5:1, which was then mixed with Al powder by weight fraction of 10%, 15% and 20%, respectively. Scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction were used to study the microstructure, chemical composition and phase composition of the coating. Results showed that the coating had satisfied metallurgical bonding with the magnesium substrate. Al3Mg2, Al12Mg17, Al3Ti and TiC were formed by in-situ reaction. The coatings have micro-hardness of 348HV, which is about 5-6 times higher than that of AZ91D. The wear resistance and corrosion resistance of the coatings are enhanced with the addition of the mixed powder.

Intrinsic bacterial biodegradation of petroleum contamination demonstrated in situ using natural abundance, molecular-level 14C analysis

International Nuclear Information System (INIS)

Slater, G.F.; Nelson, R.K.; Kile, B.M.; Reddy, C.M.

2006-01-01

Natural abundance, molecular-level C 14 analysis was combined with comprehensive gas chromatography (GC x GC) to investigate, in situ, the role of intrinsic biodegradation in the loss of petroleum hydrocarbons from the rocky, inter-tidal zone impacted by the Bouchard 120 oil spill. GC x GC analysis indicated accelerated losses of n-alkane components of the residual petroleum hydrocarbons between day 40 and day 50 after the spill. 14 C analysis of bacterial phospholipid fatty acids (PLFA) from the impacted zone on day 44 showed that the polyunsaturated fatty acids attributed to the photoautotrophic component of the microbial community had the same ( 14 C as the local dissolved inorganic carbon (DIG), indicating that this DIG was their carbon source. In contrast there was significant (C depletion in the saturated and mono-unsaturated PLFA indicating incorporation of petroleum carbon. This correlation between the observed accelerated n-alkane losses and microbial incorporation of (C-depleted carbon directly demonstrated, in situ, that intrinsic biodegradation was affecting the petroleum. Since the majority of organic contaminants originate from petroleum feed-stocks, in situ molecular-level 14 C analysis of microbial PLFA can provide insights into the occurrence and pathways of biodegradation of a wide range of organic contaminants. (Author)

In situ TEM annealing of ion-amorphized Hi Nicalon S and Tyranno SA3 SiC fibers

Energy Technology Data Exchange (ETDEWEB)

Huguet-Garcia, J., E-mail: juan.huguet-garcia@cea.fr [CEA, DEN, Service de Recherches Métallurgiques Appliquées, F-91191 Gif-sur-Yvette (France); Jankowiak, A. [CEA, DEN, Service de Recherches Métallurgiques Appliquées, F-91191 Gif-sur-Yvette (France); Miro, S. [CEA, DEN, Service de Recherches en Métallurgie Physique, F-91191 Gif-sur-Yvette (France); Meslin, E. [CEA, DEN, Service de Recherches en Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Serruys, Y. [CEA, DEN, Service de Recherches en Métallurgie Physique, F-91191 Gif-sur-Yvette (France); Costantini, J.-M. [CEA, DEN, Service de Recherches Métallurgiques Appliquées, F-91191 Gif-sur-Yvette (France)

2016-05-01

In this work, recrystallization of ion-amorphized Hi Nicalon Type S and Tyranno SA3 SiC fibers (4 MeV Au{sup 3+}, 2 × 10{sup 15} cm{sup −2}) has been studied via in situ TEM annealing. Both fibers show a two-step recovery process of the radiation damage. First recovery stage starts at temperatures as low as 250 °C and implies recovery of the radiation swelling. Eventually the amorphous layer recrystallizes with no signs of polytype change (3C-SiC). Recrystallization temperatures yield 900–920 °C and 930 °C for the HNS and the TSA3 respectively. HNS fiber shows columnar recrystallization perpendicular to the amorphous–crystalline interphase with a grain growth rate of ∼20 nm min{sup −1}. On the other hand, recrystallization of TSA3 fiber is rather “spontaneous” with no preferential growth direction. The different recrystallization is attributed to the different microstructure of the fibers.

In situ TEM annealing of ion-amorphized Hi Nicalon S and Tyranno SA3 SiC fibers

International Nuclear Information System (INIS)

Huguet-Garcia, J.; Jankowiak, A.; Miro, S.; Meslin, E.; Serruys, Y.; Costantini, J.-M.

2016-01-01

In this work, recrystallization of ion-amorphized Hi Nicalon Type S and Tyranno SA3 SiC fibers (4 MeV Au"3"+, 2 × 10"1"5 cm"−"2) has been studied via in situ TEM annealing. Both fibers show a two-step recovery process of the radiation damage. First recovery stage starts at temperatures as low as 250 °C and implies recovery of the radiation swelling. Eventually the amorphous layer recrystallizes with no signs of polytype change (3C-SiC). Recrystallization temperatures yield 900–920 °C and 930 °C for the HNS and the TSA3 respectively. HNS fiber shows columnar recrystallization perpendicular to the amorphous–crystalline interphase with a grain growth rate of ∼20 nm min"−"1. On the other hand, recrystallization of TSA3 fiber is rather “spontaneous” with no preferential growth direction. The different recrystallization is attributed to the different microstructure of the fibers.

In-situ generation of Li2FeSiO4/C nanocomposite as cathode material for lithium ion battery

International Nuclear Information System (INIS)

Yi, Jin; Hou, Meng-yan; Bao, Hong-liang; Wang, Cong-xiao; Wang, Jian-qiang; Xia, Yong-yao

2014-01-01

Highlights: • A Li 2 FeSiO 4 /C nanocomposite is prepared via thermal vapor deposition technology. • The Li 2 FeSiO 4 /C nanocomposite is free from impurity and coated with carbon layer. • The Li 2 FeSiO 4 /C nanocomposite exhibits good rate capability and cycling stability. • Lithium benzoate serves as both lithium and carbon sources. - Abstract: A Li 2 FeSiO 4 /C nanocomposite is prepared via solvothermal method in combination with carbon coating technology. The as-prepared Li 2 FeSiO 4 /C nanocomposite is a single phase Li 2 FeSiO 4 with nano-tickness coated carbon layer and connected by the mutual cross-linked carbon conductive matrix. As cathode material for lithium ion battery, the composite delivers a discharge capacity of 154 mAh g −1 at 1 C and exhibits good rate capability with a discharge capacity of 106 mAh g −1 at the rate of 10 C, which is ascribed to the small particle size and enhanced electronic conductivity using carbon coating technology. The as-prepared Li 2 FeSiO 4 /C nanocomposite also behaves a good cycling stability with capacity retention of over 100 cycles

Influence of nitrogen deficiency on the metabolism of photoassimilated 14C in sunflower

International Nuclear Information System (INIS)

Stanev, V.; Angelov, M.; Popov, G.

1981-01-01

In experiments carried out on sunflower the specific changes in the metabolism of photoassimilated 14 C caused by nitrogen deficiency are investigated. The data presented show that nitrogen deficiency in sunflower inhibits the metabolism of photoassimilated 14 C through phosphoglyceric acid and phosphoenolpyruvate and directs it to a great extent through hexo-monophosphates towards the hydrocarbons-sucrose and starch. (authors)

In Situ GISAXS Study on Solvent Vapour Induced Orientation Switching in PS-b-P4VP Block Copolymer Thin Films

International Nuclear Information System (INIS)

Gowd, E Bhoje; Boehme, Marcus; Stamm, Manfred

2010-01-01

We investigated the orientation changes of cylindrical P4VP microdomains in PS-b-P4VP thin films upon annealing in different solvent vapours using the time-resolved in situ grazing-incidence small-angle X-ray scattering (GISAXS) for the first time. Swelling of perpendicular cylinders (C perpendicular) in a non-selective solvent vapours (chloroform) leads to the orientation change to in-plane cylinders (C//) and it occurs through a disordered state. On the other hand, swelling of perpendicular cylinders (C perpendicular) in a selective solvent vapours (1,4-dioxane) leads the morphological change from cylindrical to BCC spherical morphology. Solvent evaporation results in shrinkage of the matrix in the vertical direction and subsequently merges the spheres into the perpendicularly aligned cylinders. The selectivity of the solvent to constituting blocks and the solvent evaporation rate may be mainly responsible for such orientation change of cylindrical P4VP microdomains in PS-b-P4VP thin films.

In Situ GISAXS Study on Solvent Vapour Induced Orientation Switching in PS-b-P4VP Block Copolymer Thin Films

Energy Technology Data Exchange (ETDEWEB)

Gowd, E Bhoje; Boehme, Marcus; Stamm, Manfred, E-mail: gowd@ipfdd.de, E-mail: bhojegowd@yahoo.com [Department of Nanostructured Materials Leibniz Institute of Polymer Research Dresden Hohe Strasse 6, 01069, Dresden (Germany)

2010-11-15

We investigated the orientation changes of cylindrical P4VP microdomains in PS-b-P4VP thin films upon annealing in different solvent vapours using the time-resolved in situ grazing-incidence small-angle X-ray scattering (GISAXS) for the first time. Swelling of perpendicular cylinders (C perpendicular) in a non-selective solvent vapours (chloroform) leads to the orientation change to in-plane cylinders (C//) and it occurs through a disordered state. On the other hand, swelling of perpendicular cylinders (C perpendicular) in a selective solvent vapours (1,4-dioxane) leads the morphological change from cylindrical to BCC spherical morphology. Solvent evaporation results in shrinkage of the matrix in the vertical direction and subsequently merges the spheres into the perpendicularly aligned cylinders. The selectivity of the solvent to constituting blocks and the solvent evaporation rate may be mainly responsible for such orientation change of cylindrical P4VP microdomains in PS-b-P4VP thin films.

In Situ AFM Study of Crystal Growth on a Barite (001 Surface in BaSO4 Solutions at 30 °C

Directory of Open Access Journals (Sweden)

Yoshihiro Kuwahara

2016-11-01

Full Text Available The growth behavior and kinetics of the barite (001 surface in supersaturated BaSO4 solutions (supersaturation index (SI = 1.1–4.1 at 30 °C were investigated using in situ atomic force microscopy (AFM. At the lowest supersaturation, the growth behavior was mainly the advancement of the initial step edges and filling in of the etch pits formed in the water before the BaSO4 solution was injected. For solutions with higher supersaturation, the growth behavior was characterized by the advance of the and [010] half-layer steps with two different advance rates and the formation of growth spirals with a rhombic to bow-shaped form and sector-shaped two-dimensional (2D nuclei. The advance rates of the initial steps and the two steps of 2D nuclei were proportional to the SI. In contrast, the advance rates of the parallel steps with extremely short step spacing on growth spirals were proportional to SI2, indicating that the lateral growth rates of growth spirals were directly proportional to the step separations. This dependence of the advance rate of every step on the growth spirals on the step separations predicts that the growth rates along the [001] direction of the growth spirals were proportional to SI2 for lower supersaturations and to SI for higher supersaturations. The nucleation and growth rates of the 2D nuclei increased sharply for higher supersaturations using exponential functions. Using these kinetic equations, we predicted a critical supersaturation (SI ≈ 4.3 at which the main growth mechanism of the (001 face would change from a spiral growth to a 2D nucleation growth mechanism: therefore, the morphology of bulk crystals would change.

Ultrasonic-assisted in situ synthesis and characterization of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Feng Jie [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Mao Jian, E-mail: maojianemail@163.com [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Wen Xiaogang; Tu Mingjing [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China)

2011-09-15

Highlights: > Fe{sup 3+} as the only Fe source for preparing Fe{sub 3}O{sub 4} nanoparticles through in situ cover and sonication method. > Surface modification enables the reduction of the grain size of Fe{sub 3}O{sub 4}. > Increasing temperature reduces grain size of Fe{sub 3}O{sub 4} until it exceeds 80 deg. C. > Increasing pH values reduces grain size of Fe{sub 3}O{sub 4} until it exceeds 11. > Saturation magnetizations depend on the grain size of Fe{sub 3}O{sub 4} nanoparticles. - Abstract: Superparamagnetic Fe{sub 3}O{sub 4} nanoparticles were synthesized via a modified coprecipitation method, and were characterized with X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Zeta potential and FT-IR, respectively. The influences of different kinds of surfactants (sodium dodecyl benzene sulfonate, polyethyleneglycol, oleic acid and dextran), temperatures and pH values on the grain size and properties were also investigated. In this method, Fe{sup 3+} was used as the only Fe source and partially reduced to Fe{sup 2+} by the reducing agent with precise content. The following reaction between Fe{sup 3+}, Fe{sup 2+} and hydroxide radical brought pure Fe{sub 3}O{sub 4} nanoparticles. The tiny fresh nanoparticles were coated in situ with surfactant under the action of sonication. Comparing with uncoated sample, the mean grain size and saturation magnetization of coated Fe{sub 3}O{sub 4} nanoparticles decrease from 18.4 nm to 5.9-9.0 nm, and from 63.89 emu g{sup -1} to 52-58 emu g{sup -1} respectively. When oleic was used as the surfactant, the mean grain size of Fe{sub 3}O{sub 4} nanoparticles firstly decreases with the increase of reaction temperature, but when the temperature is exceed to 80 deg. C, the continuous increase of temperature resulted in larger nanoparticles. the grain size decreases gradually with the increasing of pH values, and it remains unchanged when the PH value is up to 11. The saturation magnetization of as-prepared Fe{sub 3}O{sub 4

Control of Lactose Transport, β-Galactosidase Activity, and Glycolysis by CcpA in Streptococcus thermophilus : Evidence for Carbon Catabolite Repression by a Non-Phosphoenolpyruvate-Dependent Phosphotransferase System Sugar

NARCIS (Netherlands)

Bogaard, Patrick T.C. van den; Kleerebezem, Michiel; Kuipers, Oscar P.; Vos, Willem M. de

2000-01-01

Streptococcus thermophilus, unlike many other gram-positive bacteria, prefers lactose over glucose as the primary carbon and energy source. Moreover, lactose is not taken up by a phosphoenolpyruvate-dependent phosphotransferase system (PTS) but by the dedicated transporter LacS. In this paper we

Enhanced visible light photocatalytic H{sub 2} evolution of metal-free g-C{sub 3}N{sub 4}/SiC heterostructured photocatalysts

Energy Technology Data Exchange (ETDEWEB)

Wang, Biao, E-mail: wangbiao@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Jingtao, E-mail: zhangjtao@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510006 (China); Huang, Feng, E-mail: huangfeng@mail.sysu.edu.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510006 (China)

2017-01-01

Highlights: • Novel g-C{sub 3}N{sub 4}/SiC composite was prepared by synthesizing g-C{sub 3}N{sub 4} on the surface of SiC. • g-C{sub 3}N{sub 4}/SiC composites exhibit much higher H{sub 2} production activity than pure g-C{sub 3}N{sub 4}. • The g-C{sub 3}N{sub 4}/SiC heterojunction mainly accounts for improved photocatalytic activity. - Abstract: g-C{sub 3}N{sub 4} has been attracting much attention for application in visible light photocatalytic water splitting due to its suitable band structure, and high thermal and chemical stability. However, the rapid recombination of photogenerated carriers has inhibited its wide use. For this reason, novel g-C{sub 3}N{sub 4}/SiC composites were prepared via in situ synthesis of g-C{sub 3}N{sub 4} on the surface of SiC, with which g-C{sub 3}N{sub 4} shows tight interaction (chemical bonding). The g-C{sub 3}N{sub 4}/SiC composites exhibit high stability in H{sub 2} production under irradiation with visible light (λ ≥ 420 nm), demonstrating a maximum of 182 μmol g{sup −1} h{sup −1}, being 3.4 times higher than that of pure g-C{sub 3}N{sub 4}. The enhanced photocatalytic H{sub 2} production ability for g-C{sub 3}N{sub 4}/SiC photocatalysts is primarily ascribed to the combined effects of enhanced separation of photogenerated carriers through efficient migration of electron and enlarged surface areas, in addition to the possible contributions of increased hydrophilicity of SiC and polymerization degree of g-C{sub 3}N{sub 4}. This study may provide new insights into the development of g-C{sub 3}N{sub 4}-based composites as stable and efficient photocatalysts for H{sub 2} production from water splitting.

De novo Transcriptome Assembly and Comparison of C3, C3-C4, and C4 Species of Tribe Salsoleae (Chenopodiaceae

Directory of Open Access Journals (Sweden)

Maximilian Lauterbach

2017-11-01

Full Text Available C4 photosynthesis is a carbon-concentrating mechanism that evolved independently more than 60 times in a wide range of angiosperm lineages. Among other alterations, the evolution of C4 from ancestral C3 photosynthesis requires changes in the expression of a vast number of genes. Differential gene expression analyses between closely related C3 and C4 species have significantly increased our understanding of C4 functioning and evolution. In Chenopodiaceae, a family that is rich in C4 origins and photosynthetic types, the anatomy, physiology and phylogeny of C4, C2, and C3 species of Salsoleae has been studied in great detail, which facilitated the choice of six samples of five representative species with different photosynthetic types for transcriptome comparisons. mRNA from assimilating organs of each species was sequenced in triplicates, and sequence reads were de novo assembled. These novel genetic resources were then analyzed to provide a better understanding of differential gene expression between C3, C2 and C4 species. All three analyzed C4 species belong to the NADP-ME type as most genes encoding core enzymes of this C4 cycle are highly expressed. The abundance of photorespiratory transcripts is decreased compared to the C3 and C2 species. Like in other C4 lineages of Caryophyllales, our results suggest that PEPC1 is the C4-specific isoform in Salsoleae. Two recently identified transporters from the PHT4 protein family may not only be related to the C4 syndrome, but also active in C2 photosynthesis in Salsoleae. In the two populations of the C2 species S. divaricata transcript abundance of several C4 genes are slightly increased, however, a C4 cycle is not detectable in the carbon isotope values. Most of the core enzymes of photorespiration are highly increased in the C2 species compared to both C3 and C4 species, confirming a successful establishment of the C2 photosynthetic pathway. Furthermore, a function of PEP-CK in C2 photosynthesis

Growth of the C4 dicot Flaveria bidentis: photosynthetic acclimation to low light through shifts in leaf anatomy and biochemistry.

Science.gov (United States)

Pengelly, Jasper J L; Sirault, Xavier R R; Tazoe, Youshi; Evans, John R; Furbank, Robert T; von Caemmerer, Susanne

2010-09-01

In C(4) plants, acclimation to growth at low irradiance by means of anatomical and biochemical changes to leaf tissue is considered to be limited by the need for a close interaction and coordination between bundle sheath and mesophyll cells. Here differences in relative growth rate (RGR), gas exchange, carbon isotope discrimination, photosynthetic enzyme activity, and leaf anatomy in the C(4) dicot Flaveria bidentis grown at a low (LI; 150 micromol quanta m(2) s(-1)) and medium (MI; 500 micromol quanta m(2) s(-1)) irradiance and with a 12 h photoperiod over 36 d were examined. RGRs measured using a 3D non-destructive imaging technique were consistently higher in MI plants. Rates of CO(2) assimilation per leaf area measured at 1500 micromol quanta m(2) s(-1) were higher for MI than LI plants but did not differ on a mass basis. LI plants had lower Rubisco and phosphoenolpyruvate carboxylase activities and chlorophyll content on a leaf area basis. Bundle sheath leakiness of CO(2) (phi) calculated from real-time carbon isotope discrimination was similar for MI and LI plants at high irradiance. phi increased at lower irradiances, but more so in MI plants, reflecting acclimation to low growth irradiance. Leaf thickness and vein density were greater in MI plants, and mesophyll surface area exposed to intercellular airspace (S(m)) and bundle sheath surface area per unit leaf area (S(b)) measured from leaf cross-sections were also both significantly greater in MI compared with LI leaves. Both mesophyll and bundle sheath conductance to CO(2) diffusion were greater in MI compared with LI plants. Despite being a C(4) species, F. bidentis is very plastic with respect to growth irradiance.

In situ preparation of (TiB + TiC + Nd2O3)/Ti composites by powder metallurgy

International Nuclear Information System (INIS)

Lu Junqiang; Qin Jining; Lu Weijie; Liu Yang; Gu Jiajun; Zhang Di

2009-01-01

Titanium matrix composites reinforced with multiple ceramic particulates TiB, TiC and Nd 2 O 3 were prepared by powder metallurgy utilizing the chemical reactions among Ti, B 4 C, NdB 6 and oxygen in Ti powder. The thermodynamic feasibility of the in situ reaction has been calculated. The phases were identified by X-ray diffraction (XRD). The result shows that multiple ceramic phases TiB, TiC and Nd 2 O 3 particulates have been synthesized. The microstructures were examined by means of optical microscopy (OM), scanning electron microscopy (SEM), backscattered electron microscopy and transmission electron microscope (TEM). The results show that the reinforcements are distributed uniformly in the matrix alloy and grow in different shapes. TiB grows in needle shape; TiC and Nd 2 O 3 grow in equiaxed or near-equiaxed shapes. The addition of NdB 6 is beneficial to grain refinement, grain-boundary purification and porosity reduction

Transition Metal Free C-N Bond Forming Dearomatizations and Aryl C-H Aminations by in Situ Release of a Hydroxylamine-Based Aminating Agent.

Science.gov (United States)

Farndon, Joshua J; Ma, Xiaofeng; Bower, John F

2017-10-11

We outline a simple protocol that accesses directly unprotected secondary amines by intramolecular C-N bond forming dearomatization or aryl C-H amination. The method is dependent on the generation of a potent electrophilic aminating agent released by in situ deprotection of O-Ts activated N-Boc hydroxylamines.

Cytochrome C Dynamics at Gold and Glassy Carbon Surfaces Monitored by in Situ Scanning Tunnel Microscopy

DEFF Research Database (Denmark)

Andersen, Jens Enevold Thaulov; Møller, Per; Pedersen, Marianne Vind

1995-01-01

We have investigated the absorption of cytochrome c on gold and glassy carbon substrates by in situ scanning tunnel microscopy under potentiostatic control of both substrate and tip. Low ionic strength and potential ranges where no Faradaic current flows were used. Cyt c aggregates into flat...

In situ catalytic synthesis of high-graphitized carbon-coated LiFePO4 nanoplates for superior Li-ion battery cathodes.

Science.gov (United States)

Ma, Zhipeng; Fan, Yuqian; Shao, Guangjie; Wang, Guiling; Song, Jianjun; Liu, Tingting

2015-02-04

The low electronic conductivity and one-dimensional diffusion channel along the b axis for Li ions are two major obstacles to achieving high power density of LiFePO4 material. Coating carbon with excellent conductivity on the tailored LiFePO4 nanoparticles therefore plays an important role for efficient charge and mass transport within this material. We report here the in situ catalytic synthesis of high-graphitized carbon-coated LiFePO4 nanoplates with highly oriented (010) facets by introducing ferrocene as a catalyst during thermal treatment. The as-obtained material exhibits superior performances for Li-ion batteries at high rate (100 C) and low temperature (-20 °C), mainly because of fast electron transport through the graphitic carbon layer and efficient Li(+)-ion diffusion through the thin nanoplates.

(001) 3C SiC/Ni contact interface: In situ XPS observation of annealing induced Ni2Si formation and the resulting barrier height changes

Science.gov (United States)

Tengeler, Sven; Kaiser, Bernhard; Chaussende, Didier; Jaegermann, Wolfram

2017-04-01

The electronic states of the (001) 3C SiC/Ni interface prior and post annealing are investigated via an in situ XPS interface experiment, allowing direct observation of the induced band bending and the transformation from Schottky to ohmic behaviour for the first time. A single domain (001) 3C SiC sample was prepared via wet chemical etching. Nickel was deposited on the sample in multiple in situ deposition steps via RF sputtering, allowing observation of the 3C SiC/Ni interface formation. Over the course of the experiments, an upward band bending of 0.35 eV was observed, along with defect induced Fermi level pinning. This indicates a Schottky type contact behaviour with a barrier height of 0.41 eV. The subsequent annealing at 850 °C for 5 min resulted in the formation of a Ni2Si layer and a reversal of the band bending to 0.06 eV downward. Thus explaining the ohmic contact behaviour frequently reported for annealed n-type 3C SiC/Ni contacts.

Grain refinement of AZ91D magnesium alloy by a new Mg–50%Al4C3 master alloy

International Nuclear Information System (INIS)

Liu, Shengfa; Chen, Yang; Han, Hui

2015-01-01

A novel and simple method for preparing Mg–50%Al 4 C 3 (hereafter in wt.%) master alloy has been developed by powder in-situ synthesis process under argon atmosphere. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) results show the existence of Al 4 C 3 particles in this master alloy. After adding 1.8% Mg–50%Al 4 C 3 master alloy, the average grain size of α-Mg decreased from 360 μm to 154 μm. Based on the DTA test results and calculation of the planar disregistry between Al 4 C 3 and α-Mg, Al 4 C 3 particles located in the central regions of magnesium grains can act as the heterogeneous nucleus of primary α-Mg phase

Effects of thermal annealing on C/FePt granular multilayers: in situ and ex situ studies

International Nuclear Information System (INIS)

Babonneau, D; Abadias, G; Toudert, J; Girardeau, T; Fonda, E; Micha, J S; Petroff, F

2008-01-01

The comprehensive study of C/FePt granular multilayers prepared by ion-beam sputtering at room temperature and subsequent annealing is reported. The as-deposited multilayers consist of carbon-encapsulated FePt nanoparticles (average size ∼3 nm) with a disordered face-centered-cubic structure. The effects of thermal annealing on the structural and magnetic properties are investigated by using dedicated ex situ and in situ techniques, including high-resolution transmission electron microscopy, extended x-ray absorption fine structure, magnetometry, and coupled grazing incidence small-angle x-ray scattering and x-ray diffraction. Our structural data show that the particle size and interparticle distance increase slightly with annealing at temperatures below 790 K by thermally activated migration of Fe and Pt atoms. We find that thermal annealing at temperatures above 870 K results in the dramatic growth of the FePt nanoparticles by coalescence and their gradual L1 0 ordering. In addition, we observe a preferential graphitization of the carbon matrix, which provides protection against oxidation for the FePt nanoparticles. Magnetization measurements indicate that progressive magnetic hardening occurs after annealing. The dependences of the blocking temperature, saturation magnetization, coercivity, and magnetocrystalline anisotropy energy on the annealing temperature are discussed on the basis of the structural data

Photoinduced electron transfer to fullerene C70 (An in situ EPR study)

International Nuclear Information System (INIS)

Brezova, V.; Dvoranova, D.; Kostova, B.; Stasko, A.

1999-01-01

The photoexcitation of fullerene C 70 by monochromatic light (λ = 546 nm) in the presence of electron donating substrate 3,3',5,5'-tetramethyl-benzidine (TMB) resulted in the charge-transfer, quenching the fullerene triplet state and forming corresponding C 70 anion-radicals. Analogously to the photo-reduction of C 60 , two EPR signal were observed upon in situ irradiation in the cavity of EPR spectrometer. EPR singlet A characterized by g-value, g A = 2.0009 and peak-to-peak line-width, pp A = 0.013 mT was assigned to the C 70 mono-anion. Signal B (g B = 2.0011; pp B = 0.011 mT) was tentatively attributed to the C 70 di-anion or to the associated forms of mono-anions. The stabilization of photo-generated anion-radicals significantly depends on solvent polarity. (authors)

The Fast-Growing Brucella suis Biovar 5 Depends on Phosphoenolpyruvate Carboxykinase and Pyruvate Phosphate Dikinase but Not on Fbp and GlpX Fructose-1,6-Bisphosphatases or Isocitrate Lyase for Full Virulence in Laboratory Models

Directory of Open Access Journals (Sweden)

Amaia Zúñiga-Ripa

2018-04-01

Full Text Available Bacteria of the genus Brucella infect a range of vertebrates causing a worldwide extended zoonosis. The best-characterized brucellae infect domestic livestock, behaving as stealthy facultative intracellular parasites. This stealthiness depends on envelope molecules with reduced pathogen-associated molecular patterns, as revealed by the low lethality and ability to persist in mice of these bacteria. Infected cells are often engorged with brucellae without signs of distress, suggesting that stealthiness could also reflect an adaptation of the parasite metabolism to use local nutrients without harming the cell. To investigate this, we compared key metabolic abilities of Brucella abortus 2308 Wisconsin (2308W, a cattle biovar 1 virulent strain, and B. suis 513, the reference strain of the ancestral biovar 5 found in wild rodents. B. suis 513 used a larger number of C substrates and showed faster growth rates in vitro, two features similar to those of B. microti, a species phylogenomically close to B. suis biovar 5 that infects voles. However, whereas B. microti shows enhanced lethality and reduced persistence in mice, B. suis 513 was similar to B. abortus 2308W in this regard. Mutant analyses showed that B. suis 513 and B. abortus 2308W were similar in that both depend on phosphoenolpyruvate synthesis for virulence but not on the classical gluconeogenic fructose-1,6-bisphosphatases Fbp-GlpX or on isocitrate lyase (AceA. However, B. suis 513 used pyruvate phosphate dikinase (PpdK and phosphoenolpyruvate carboxykinase (PckA for phosphoenolpyruvate synthesis in vitro while B. abortus 2308W used only PpdK. Moreover, whereas PpdK dysfunction causes attenuation of B. abortus 2308W in mice, in B. suis, 513 attenuation occurred only in the double PckA-PpdK mutant. Also contrary to what occurs in B. abortus 2308, a B. suis 513 malic enzyme (Mae mutant was not attenuated, and this independence of Mae and the role of PpdK was confirmed by the lack of

In Situ Strength Model for Continuous Fibers and Multi-Scale Modeling the Fracture of C/SiC Composites

Science.gov (United States)

Zhang, Sheng; Gao, Xiguang; Song, Yingdong

2018-04-01

A new in situ strength model of carbon fibers was developed based on the distribution of defects to predict the stress-strain response and the strength of C/SiC composites. Different levels of defects in the fibers were considered in this model. The defects in the fibers were classified by their effects on the strength of the fiber. The strength of each defect and the probability that the defect appears were obtained from the tensile test of single fibers. The strength model of carbon fibers was combined with the shear-lag model to predict the stress-strain responses and the strengths of fiber bundles and C/SiC minicomposites. To verify the strength model, tensile tests were performed on fiber bundles and C/SiC minicomposites. The predicted and experimental results were in good agreement. Effects of the fiber length, the fiber number and the heat treatment on the final strengths of fiber bundles and C/SiC minicomposites were also discussed.

Recombinant thermoactive phosphoenolpyruvate carboxylase (PEPC) from Thermosynechococcus elongatus and its coupling with mesophilic/thermophilic bacterial carbonic anhydrases (CAs) for the conversion of CO2 to oxaloacetate.

Science.gov (United States)

Del Prete, Sonia; De Luca, Viviana; Capasso, Clemente; Supuran, Claudiu T; Carginale, Vincenzo

2016-01-15

With the continuous increase of atmospheric CO2 in the last decades, efficient methods for carbon capture, sequestration, and utilization are urgently required. The possibility of converting CO2 into useful chemicals could be a good strategy to both decreasing the CO2 concentration and for achieving an efficient exploitation of this cheap carbon source. Recently, several single- and multi-enzyme systems for the catalytic conversion of CO2 mainly to bicarbonate have been implemented. In order to design and construct a catalytic system for the conversion of CO2 to organic molecules, we implemented an in vitro multienzyme system using mesophilic and thermophilic enzymes. The system, in fact, was constituted by a recombinant phosphoenolpyruvate carboxylase (PEPC) from the thermophilic cyanobacterium Thermosynechococcus elongatus, in combination with mesophilic/thermophilic bacterial carbonic anhydrases (CAs), for converting CO2 into oxaloacetate, a compound of potential utility in industrial processes. The catalytic procedure is in two steps: the conversion of CO2 into bicarbonate by CA, followed by the carboxylation of phosphoenolpyruvate with bicarbonate, catalyzed by PEPC, with formation of oxaloacetate (OAA). All tested CAs, belonging to α-, β-, and γ-CA classes, were able to increase OAA production compared to procedures when only PEPC was used. Interestingly, the efficiency of the CAs tested in OAA production was in good agreement with the kinetic parameters for the CO2 hydration reaction of these enzymes. This PEPC also revealed to be thermoactive and thermostable, and when coupled with the extremely thermostable CA from Sulphurhydrogenibium azorense (SazCA) the production of OAA was achieved even if the two enzymes were exposed to temperatures up to 60 °C, suggesting a possible role of the two coupled enzymes in biotechnological processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

NewIn-situ synthesis method of magnesium matrix composites reinforced with TiC particulates

Directory of Open Access Journals (Sweden)

Zhang Xiuqing

2006-12-01

Full Text Available Magnesium matrix composites reinforced with TiC particulates was prepared using a new in-situ synthesis method of remelting and dilution technique. And measurements were performed on the composites. The results of x ray diffraction (XRD analysis confirmed that TiC particulates were synthesized during the sintering process, and they retained in magnesium matrix composites after the remelting and dilution processing. From the microstructure characterization and electron probe microanalysis (EPMA, we could see that fine TiC particulates distributed uniformly in the matrix material.

Synthesis and characterization of in situ carbon-coated Li2FeSiO4 cathode materials for lithium ion battery

International Nuclear Information System (INIS)

Yan Zipeng; Cai Shu; Miao Lijuan; Zhou Xing; Zhao Yongming

2012-01-01

Highlights: → Sucrose and L-ascorbic acid as carbon additives. → Li 2 FeSiO 4 /C were obtained under our carbon coating experimental conditions. → Graphite-rich carbon was formed uniformly when ascorbic acid was employed. → The composites employing L-ascorbic acid exhibited a large specific surface area. → Sample using L-ascorbic acid exhibited better rate performance and cycling stability. - Abstract: Li 2 FeSiO 4 /C composites with in situ carbon coating were synthesized via sol-gel method based on acid-catalyzed hydrolysis/condensation of tetraethoxysilane (TEOS) with sucrose and L-ascorbic acid as carbon additives, respectively. As-obtained Li 2 FeSiO 4 /C composites prepared with L-ascorbic acid as a carbon additive are composed of nanoparticulate Li 2 FeSiO 4 in an intimate contact with a continuous thin layer of residual carbon and exhibit large specific surface area up to 395.7 m 2 g -1 . The results indicate that structure of the residual carbon is graphene-rich with obviously lower disordered/graphene (D/G) ratio. These as-obtained Li 2 FeSiO 4 /C composites exhibit first discharge capacity of 135.3 mAh g -1 at C/16 and perform cycling stability, which are superior to those of Li 2 FeSiO 4 /C composites synthesized with sucrose as a carbon additive.

In-situ synthesis of SiC particles by the structural evolution of TiCx in Al–Si melt

International Nuclear Information System (INIS)

Nie, Jinfeng; Li, Dakui; Wang, Enzhao; Liu, Xiangfa

2014-01-01

Highlights: • A facile method to in-situ synthesize SiC was developed utilizing the structural evolution of TiC x in Al–Si melt. • The SiC particles have the size range from 2.5 to 7.5 μm and a block-like morphology. • The SiC particles and (SiC + TiB 2 ) hybrid-particles reinforced Al–18Si composite were prepared. • The wear resistance effect of SiC on the based alloy was investigated. - Abstract: A facile method has been developed to in-situ synthesize SiC particles utilizing the structural instability and evolution of TiC x in Al–Si melt. It is considered that the synthesis of SiC particles occurs via the gradual reaction between TiC x and Si atoms, whilst Si content plays the crucial role in this approach. If the Si content in the melt is above 30%, TiC x directly reacts with Si and Al to form SiC, but the needle-like TiAl x Si y phase formed simultaneously will do harm to the mechanical properties of the composites. Thus, it is proposed to add B element in the melt to transform the TiAl x Si y into TiB 2 particles. Therefore, the SiC and (SiC + TiB 2 ) hybrid-particles reinforced Al–18Si composites were successfully prepared using the method. In the composites, the SiC particles have the size range from 2.5 to 7.5 μm and a block-like morphology. Furthermore, the mechanical properties of base alloy, including the wear resistance and macro-hardness, have been obviously improved by the in-situ SiC particles. Besides, the relevant underlying mechanisms are also discussed

Ratiometric Imaging of Extracellular pH in Dental Biofilms Using C-SNARF-4

DEFF Research Database (Denmark)

Dige, Irene

pH in dental biofilms plays a central role for the development of caries lesions. For decades, pH measurements in biofilms have been limited to recording pH with electrodes/microelectrodes that do not permit monitoring horizontal pH gradients in biofilms in real-time. Quantitative fluorescent...... microscopy can overcome these problems. Objective: The aim of this demonstration study was to monitor extracellular biofilm pH microscopically with the ratiometric pH-sensitive dye C-SNARF-4 in in-situ-grown dental biofilms. Methods: Using confocal microscopy, the dye C-SNARF-4 was employed both as p...... the microscopic images in order to exclusively determine extracellular pH. We monitored the pH drop at the biofilm-substratum interface in six microscopic fields of view per biofilm for 1h after exposure to 0.4% glucose. Results: Extracellular pH dropped rapidly in all specimens. In both individuals, analysis...

In-situ formation of Ni4Ti3 precipitate and its effect on pseudoelasticity in selective laser melting additive manufactured NiTi-based composites

Science.gov (United States)

Gu, Dongdong; Ma, Chenglong

2018-05-01

Selective laser melting (SLM) additive manufacturing technology was applied to synthesize NiTi-based composites via using ball-milled Ti, Ni, and TiC mixed powder. By transmission electron microscope (TEM) characterization, it indicated that the B2 (NiTi) matrix was obtained during SLM processing. In spite of more Ti content (the Ti/Ni ratio >1), a mass of Ni-rich intermetallic compounds containing Ni4Ti3 with nanostructure features and eutectic Ni3Ti around in-situ Ti6C3.75 dendrites were precipitated. Influence of the applied laser volume energy density (VED) on the morphology and content of Ni4Ti3 precipitate was investigated. Besides, nanoindentation test of the matrix was performed in order to assess pseudoelastic recovery behavior of SLM processed NiTi-based composites. At a relatively high VED of 533 J/mm3, the maximum pseudoelastic recovery was obtained due to the lowest content of Ni4Ti3 precipitates. Furthermore, the precipitation mechanism of in-situ Ni4Ti3 was present based on the redistribution of titanium element and thermodynamics analysis, and then the relationship of Ni4Ti3 precipitate, VED and pseudoelastic recovery behavior was also revealed.

Growth and optical, magnetic and transport properties of (C4H9NH3)2MCl4 organic-inorganic hybrid films (M = Cu, Sn)

Science.gov (United States)

Aruta, C.; Licci, F.; Zappettini, A.; Bolzoni, F.; Rastelli, F.; Ferro, P.; Besagni, T.

2005-10-01

Films of (C4H9NH3)2MCl4 (M=Cu and Sn) organic-inorganic hybrid perovskites have been deposited in-situ by a single-source thermal ablation technique on glassy, crystalline and polymeric substrates. Independently of the substrate, the films were well crystallized, c-axis oriented and with a narrow rocking curve of the (0010) reflection (full width at half maximum photoluminescence spectra of typical (C4H9NH3)2SnCl4 films at 12 K had a broad yellow band, which did not correspond to any significant peak in the absorption spectrum. The films were semiconducting down to 250 K or, in the case of the best samples, down to 200 K and became insulating at lower temperature. The resistivity of the best films was (5±1) 104 Ω cm at 300 K, and the energy gap was 1.11 eV.

A specific assay for quantification of human C4c by use of an anti-C4c monoclonal antibody

DEFF Research Database (Denmark)

Pilely, Katrine; Skjoedt, Mikkel-Ole; Nielsen, Christian

2014-01-01

a mouse monoclonal antibody (mAb) that is able to detect fluid phase C4c without interference from other products generated from the complement component C4. The C4c specific mAb was tested in different enzyme-linked immunosorbent assay (ELISA) combinations with various types of in vitro activated sera...

Ultrathin g-C3N4 films supported on Attapulgite nanofibers with enhanced photocatalytic performance

Science.gov (United States)

Xu, Yongshuai; Zhang, Lili; Yin, Minghui; Xie, Dengyu; Chen, Jiaqi; Yin, Jingzhou; Fu, Yongsheng; Zhao, Pusu; Zhong, Hui; Zhao, Yijiang; Wang, Xin

2018-05-01

A novel visible-light-responsive photocatalyst is fabricated by introducing g-C3N4 ultrathin films onto the surface of attapulgite (ATP) via a simple in-situ depositing technique, in which ATP was pre-grafted using (3-Glycidyloxypropyl) trimethoxysilane (KH560) as the surfactant. A combination of XRD, FT-IR, BET, XPS, UV-vis, TEM and SEM techniques are utilized to characterize the composition, morphology and optical properties of the products. The results show that with the help of KH560, g-C3N4 presented as ultrathin layer is uniformly loaded onto the surface of ATP by forming a new chemical bond (Sisbnd Osbnd C). Comparing with g-C3N4 and ATP, ATP/g-C3N4 exhibits remarkably enhanced visible-light photocatalytic activity in degradation of methyl orange (MO) because of its high surface area, appropriate band gap and the synergistic effect between g-C3N4 and ATP. To achieve the best photocatalyst, the ratio of g-C3N4 was adjusted by controlling the mass portion between ATP-KH560 and melamine (r = m (ATP-KH560)/m (melamine)). The highest decomposition rate of methyl orange (MO) was 96.06% when r = 0.5 and this degradation efficiency remained unchanged after 4 cycles, which is 10 times as that of pure g-C3N4 particles. Possible photocatalytic mechanism is presented.

Effect of In-Situ Curing on Compressive Strength of Reactive Powder Concrete

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Bali Ika

2016-01-01

Full Text Available A development of Reactive Powder Concrete (RPC currently is the use of quartz powder as a stabilizing agent with the content to cement ratio of 30% and steam curing method in an autoclave temperature of 250ºC which produced a high compressive strength of 180 MPa. That RPC can be generated due to one reason for using the technique of steam curing in an autoclave in the laboratory. This study proposes in-situ curing method in order the curing can be applied in the field and with a reasonable compressive strength results of RPC. As the benchmarks in this study are the curing methods in laboratory that are steam curing of 90°C for 8 hours (C1, and water curing for 28 days (C2. For the in-situ curing methods that are covering with tarpaulins and flowed steam of 3 hours per day for 7 days (C3, covering with wet sacks for 28 days (C4, and covering with wet sacks for 28 days for specimen with unwashed sand as fine aggregate (C5. The comparison of compressive strength of the specimens in this study showed compressive strength of RPC with in-situ steam curing (101.64 MPa close to the compressive strength of RPC with steam curing in the laboratory with 8.2% of different. While in-situ wet curing compared with the water curing in laboratory has the different of 3.4%. These results indicated that the proposed in-situ curing methods are reasonable good in term of the compressive strength that can be achieved.

Investigation of the fabrication processes of AlGaN/AlN/GaN HEMTs with in situ Si3N4 passivation

International Nuclear Information System (INIS)

Tomosh, K. N.; Pavlov, A. Yu.; Pavlov, V. Yu.; Khabibullin, R. A.; Arutyunyan, S. S.; Maltsev, P. P.

2016-01-01

The optimum mode of the in situ plasma-chemical etching of a Si 3 N 4 passivating layer in C 3 F 8 /O 2 medium is chosen for the case of fabricating AlGaN/AlN/GaN HEMTs. It is found that a bias of 40–50 V at a high-frequency electrode provides anisotropic etching of the insulator through a resist mask and introduces no appreciable radiation-induced defects upon overetching of the insulator films in the region of gate-metallization formation. To estimate the effect of in situ Si 3 N 4 growth together with the heterostructure in one process on the AlGaN/AlN/GaN HEMT characteristics, transistors with gates without the insulator and with gates through Si 3 N 4 slits are fabricated. The highest drain current of the AlGaN/AlN/GaN HEMT at 0 V at the gate is shown to be 1.5 times higher in the presence of Si 3 N 4 than without it.

Potential Hazards Relating to Pyrolysis of c-C4F8O, n-C4F10 and c-C4F8 in selected gaseous diffusion plant operations

International Nuclear Information System (INIS)

Trowbridge, L.D.

2000-01-01

As part of a program intended to replace the present evaporative coolant at the gaseous diffusion plants (GDPs) with a non-ozone-depleting alternate, a series of investigations of the suitability of candidate substitutes is under way. This report summarizes studies directed at estimating the chemical and thermal stability of three candidate coolants, c-C 4 F 8 O, n-C 4 F 10 and c-C 4 4F 8 , in a few specific environments to be found in gaseous diffusion plant operations

Major alterations in transcript profiles between C3-C4 and C4 photosynthesis of an amphibious species Eleocharis baldwinii.

Science.gov (United States)

Chen, Taiyu; Zhu, Xin-Guang; Lin, Yongjun

2014-09-01

Engineering C4 photosynthetic metabolism into C3 crops is regarded as a major strategy to increase crop productivity, and clarification of the evolutionary processes of C4 photosynthesis can help the better use of this strategy. Here, Eleocharis baldwinii, a species in which C4 photosynthesis can be induced from a C3-C4 state under either environmental or ABA treatments, was used to identify the major transcriptional modifications during the process from C3-C4 to C4. The transcriptomic comparison suggested that in addition to the major differences in C4 core pathway, the pathways of glycolysis, citrate acid metabolism and protein synthesis were dramatically modified during the inducement of C4 photosynthetic states. Transcripts of many transporters, including not only metabolite transporters but also ion transporters, were dramatically increased in C4 photosynthetic state. Many candidate regulatory genes with unidentified functions were differentially expressed in C3-C4 and C4 photosynthetic states. Finally, it was indicated that ABA, auxin signaling and DNA methylation play critical roles in the regulation of C4 photosynthesis. In summary, by studying the different photosynthetic states of the same species, this work provides the major transcriptional differences between C3-C4 and C4 photosynthesis, and many of the transcriptional differences are potentially related to C4 development and therefore are the potential targets for reverse genetics studies.

Development of an in-situ synthesized multi-component reinforced Al–4.5%Cu–TiC metal matrix composite by FAS technique – Optimization of process parameters

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Biswajit Das

2016-03-01

Full Text Available In the present investigation, an in-situ multi-component reinforced aluminium copper alloy based metal matrix composite was fabricated by the flux assisted synthesis (FAS technique. It was found from the optical microscopy analysis that TiC particles are formed in the composite. Further the present research investigates the feasibility and dry machining characteristics of Al–4.5%Cu/5TiC metal matrix composite in CNC milling machine using uncoated solid carbide end mill cutter. The effect of the machining parameters such as feed, cutting speed, depth of cut on the response parameters such as cutting force and COM is determined by using analysis of variance (ANOVA. From the analysis it was found that cutting speed and depth of cut played a major role in affecting cutting force. Multi output optimization of the process was carried out by the application of the Taguchi method with fuzzy logic, and the confirmatory test has revealed the accuracy of the developed model. For predicting the response parameters, regression equations were developed and verified with a number of test cases and it was observed that the percentage error for both responses is less than ±3%, which indicates there is a close agreement between the predicted and the measured results.

X-ray photoelectron spectroscopy studies of nitridation on 4H-SiC (0001) surface by direct nitrogen atomic source

International Nuclear Information System (INIS)

Chai, J. W.; Pan, J. S.; Zhang, Z.; Wang, S. J.; Chen, Q.; Huan, C. H. A.

2008-01-01

A Si 3 N 4 passivation layer has been successfully grown on the 4H-SiC (0001) surface by direct atomic source nitridation at various substrate temperatures. In situ x-ray photoelectron spectroscopy measurements show that higher substrate temperature leads to higher nitridation rate and good crystallinity of the passivation layer. A thin oxynitride layer on the top of the Si 3 N 4 was observed due to the residual O in the vacuum system, but was decomposed during annealing. In the meantime, excess C was found to be effectively removed by the reactive atomic N source

Real-time PCR quantification of human complement C4A and C4B genes

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Fust George

2006-01-01

Full Text Available Abstract Background The fourth component of human complement (C4, an essential factor of the innate immunity, is represented as two isoforms (C4A and C4B in the genome. Although these genes differ only in 5 nucleotides, the encoded C4A and C4B proteins are functionally different. Based on phenotypic determination, unbalanced production of C4A and C4B is associated with several diseases, such as systemic lupus erythematosus, type 1 diabetes, several autoimmune diseases, moreover with higher morbidity and mortality of myocardial infarction and increased susceptibility for bacterial infections. Despite of this major clinical relevance, only low throughput, time and labor intensive methods have been used so far for the quantification of C4A and C4B genes. Results A novel quantitative real-time PCR (qPCR technique was developed for rapid and accurate quantification of the C4A and C4B genes applying a duplex, TaqMan based methodology. The reliable, single-step analysis provides the determination of the copy number of the C4A and C4B genes applying a wide range of DNA template concentration (0.3–300 ng genomic DNA. The developed qPCR was applied to determine C4A and C4B gene dosages in a healthy Hungarian population (N = 118. The obtained data were compared to the results of an earlier study of the same population. Moreover a set of 33 samples were analyzed by two independent methods. No significant difference was observed between the gene dosages determined by the employed techniques demonstrating the reliability of the novel qPCR methodology. A Microsoft Excel worksheet and a DOS executable are also provided for simple and automated evaluation of the measured data. Conclusion This report describes a novel real-time PCR method for single-step quantification of C4A and C4B genes. The developed technique could facilitate studies investigating disease association of different C4 isotypes.

In Situ Studies of Fe4+ Stability in β-Li3Fe2(PO4)3 Cathodes for Li Ion Batteries

DEFF Research Database (Denmark)

Christiansen, Ane Sælland; Johnsen, Rune E.; Norby, Poul

2015-01-01

In commercial Fe-based batteries the Fe2+/Fe3+ oxidation states are used, however by also utilizing the Fe4+ oxidation state, intercalation of up to two Li ions per Fe ion could be possible. In this study, we investigate whether Fe4+ can be formed and stabilized in β-Li3Fe2(PO4)3. The work includes...... of Fe4+ formation. Oxidation of the organic electrolyte is inevitable at 4.5 V but this alone cannot explain the volume change. Instead, a reversible oxygen redox process (O2− → O−) could possibly explain and charge compensate for the reversible extraction of lithium ions from β-Li3Fe2(PO4)3....... in situ synchrotron X-ray powder diffraction studies (XRPD) during charging of β-Li3Fe2(PO4)3 up to 5.0 V vs. Li/Li+. A novel capillary-based micro battery cell for in situ XRPD has been designed for this. During charge, a plateau at 4.5 V was found and a small contraction in volume was observed...

Designing Z-scheme 2D-C{sub 3}N{sub 4}/Ag{sub 3}VO{sub 4} hybrid structures for improved photocatalysis and photocatalytic mechanism insight

Energy Technology Data Exchange (ETDEWEB)

She, Xiaojie; Yi, Jianjian; Xu, Yuanguo; Huang, Liying; Ji, Haiyan; Xu, Hui; Li, Huaming [School of the Environment and Safety Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013 (China); Song, Yanhua [School of Environmental and Chemical, Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China)

2017-06-15

The two-dimensional oxygen-modified g-C{sub 3}N{sub 4} nanosheets-loaded Ag{sub 3}VO{sub 4} (2D-C{sub 3}N{sub 4}/Ag{sub 3}VO{sub 4}) photocatalysts were synthesized successfully via a facile in situ deposition method. The comprehensive characterizations were employed to characterize the morphologies, structures, chemical states, optical and electronic properties and photocatalytic performances of the samples. The 20% 2D-C{sub 3}N{sub 4}/Ag{sub 3}VO{sub 4} showed the best photocatalytic activity on the degradation of RhB and BPA. The enhanced photocatalytic activity is ascribed to the effective electron-hole separation efficiency and the larger specific surface area. The photogenerated electrons and holes can quickly separate by Z-scheme passageway in composite. Through ESR analysis, the photocatalytic mechanism was also researched in detail. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

UV-light-assisted ethanol sensing characteristics of g-C3N4/ZnO composites at room temperature

Science.gov (United States)

Zhai, Jiali; Wang, Tao; Wang, Chuang; Liu, Dechen

2018-05-01

A highly efficient UV-light-assisted room temperature sensor based on g-C3N4/ZnO composites were prepared by an in situ precipitation method. The thermostability, composition, structure, and morphology properties of the as-prepared g-C3N4/ZnO composites were characterized by TGA, XRD, FT-IR, TEM, and XPS, respectively. And then, we studied the ethanol (C2H5OH) sensing performance of the g-C3N4/ZnO composites at the room temperature. Compared with pure ZnO and g-C3N4, the gas sensing activity of g-C3N4/ZnO composites was greatly improved at room temperature, for example, the g-C3N4/ZnO-8% composites showed an obvious response of 121-40 ppm C2H5OH at room temperature, which was 60 times higher than the pure ZnO based on the sensors under the same condition. The great enhancement of the C2H5OH sensing properties of composites can be understood by the efficient separation of photogenerated charge carriers of g-C3N4/ZnO heterogeneous and the UV-light catalytic effect. Finally, a possible mechanism for the gas sensing activity was proposed.

In situ synthesis and formation mechanism of ZrC and ZrB2 by combustion synthesis from the Co-Zr-B4C system

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Mengxian Zhang

2015-09-01

Full Text Available ZrC-ZrB2-based composites were prepared by combustion synthesis (CS reaction from 10 wt.% to 50 wt.% Co-Zr-B4C powder mixtures. With increasing Co contents, the particle sizes of near-spherical ZrC and platelet-like ZrB2 decreased from 1 μm to 0.5 μm and from 5 μm to 2 μm, respectively. In addition, the formation mechanism of ZrC and ZrB2 was explored by the phase transition and microstructure evolution on the combustion wave quenched sample in combination with differential scanning calorimeter analysis. The results showed that the production of ZrC was ascribed to the solid-solid reaction between Zr and C and the precipitation from the Co-Zr-B-C melt, while ZrB2 was prepared from the saturated liquid. The low B concentration in the Co-Zr-B-C liquid and high cooling rate during the CS process led to the presence of Co2B and ZrCo3B2 in the composites. The addition of Co in the Co-Zr-B4C system not only prevented ZrC and ZrB2 particulates from growing, but also promoted the occurrence of ZrC-ZrB2-forming reaction.

A quasi-in-situ EBSD observation of the transformation from rolling texture to recrystallization texture in V-4Cr-4Ti alloy

Energy Technology Data Exchange (ETDEWEB)

Peng, Lixia [Institute of Materials Research, China Academy of Engineering Physics, Jiangyou, Sichuan Province 621908 (China); Li, Xiongwei [Institute of Metal Research, China Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Fan, Zhijian [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan Province 621900 (China); Jiang, Chunli; Zhou, Ping [Institute of Materials Research, China Academy of Engineering Physics, Jiangyou, Sichuan Province 621908 (China); Lai, Xinchun, E-mail: laixinchun@caep.cn [Institute of Materials Research, China Academy of Engineering Physics, Jiangyou, Sichuan Province 621908 (China)

2017-04-15

Recrystallization texture evolution of rolled V-4Cr-4Ti alloy has been investigated by quasi-in-situ EBSD (electron back-scattering diffraction) method. Concurrently, the precipitates were characterized by SEM (Scanning Electron Microscopy). It was found that both the initial rolling textures and the distribution of the precipitates affected the formation of the recrystallization texture. It was revealed that the texture transformations of (558) 〈110〉 + (665) 〈110〉 to (334) 〈483〉 + (665) 〈1 1 2.4〉 were possibly attributed to the selective drag induced by the sparsely dispersed Ti-rich precipitates. While the densely distributed Ti-rich precipitates were responsible for the randomized recrystallization texture. Finally, when the precipitates were absent, the orientation changes from (112) 〈110〉 and (558) 〈110〉 to (111) 〈112〉 and (001) <110> to (001) <520> were observed. - Highlights: • Micro recrystallization texture evolution in V-4Cr-4Ti alloys is reported for the first time. • The volume fraction of Ti-rich precipitates has significant effect on the recrystallization texture evolution. • The dissolution of the Ti-rich precipitates above 1100 °C induces the strengthening of (111) <112> texture.

Effect of in situ pyrolysis of acetylene (C2H2) gas as a carbon source on the electrochemical performance of LiFePO4 for rechargeable lithium-ion batteries

Science.gov (United States)

Saroha, Rakesh; Panwar, Amrish K.

2017-06-01

The intention of this work is to study the effect of in situ pyrolysis of acetylene (C2H2) gas used as a carbon source on the physicochemical and electrochemical performance of pristine LiFePO4 (LFP). Acetylene gas, which decomposed to carbon and methane along with some side products when exposed to high temperature (>625 °C), is used as a carbon source for coating over the surface of LFP particles. Thermogravimetric (TGA) measurements were performed in an air atmosphere, primarily to estimate the exact amount of carbon deposited on the surface of the olivine cathode material due to the decomposition of C2H2 gas. Raman and TGA results confirm the presence of carbon as coated on the surface of the prepared compositions. Among all the synthesized samples, LFP with 10 min C2H2 treatment (LFPC10) shows the highest discharge capacity at all C-rates and exhibits excellent rate performance. LFPC10 delivers a specific discharge capacity of 144 (±5) mAh g-1 (~85% of the theoretical capacity of 170 mAh g-1) at 0.1C rate. LFPC10 demonstrates the best cycling performance as it offers an initial discharge capacity of about 117 (±5) mAh g-1 (~69% of the theoretical capacity) at 1C-rate and has 97% capacity retention even after 100 charge/discharge cycles.

Characterization on the Phase Structure of TiC/Al-4.5Cu In-Situ Composites%TiC/A1-4.5Cu原位复合材料的相结构特征

Institute of Scientific and Technical Information of China (English)

卫蓉; 董晟全; 梁艳峰; 杨通

2008-01-01

采用熔体接触反应法制备了TiC/Al-4.5Cu复合材料,通过光学显微镜、透射电镜等,对TiC颗粒增强Al-4.5Cu原位复合材料的相结构进行分析.结果表明,5%TiC/Al-4.5Cu原位复合材料的主要增强相为TiC;TiC弥散分布在α-Al基体中,与基体结合良好且界面光滑.在5%TiC/Al-4.5Cu原位复合材料中TiC呈球形或近球形,颗粒细小,其尺寸约为0.1～0.5μm;而在5%TiC/Al-4.5Cu-XMg原位复合材料中TiC呈规则六边形,颗粒较大,其尺寸约为0.5～0.8 μm.

In situ measurement of tritium permeation through stainless steel

Science.gov (United States)

Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.

2013-06-01

The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

Oxidation protection and behavior of in-situ zirconium diboride–silicon carbide coating for carbon/carbon composites

International Nuclear Information System (INIS)

Li, Lu; Li, Hejun; Yin, Xuemin; Chu, Yanhui; Chen, Xi; Fu, Qiangang

2015-01-01

Highlights: • ZrB 2 –SiC coating was prepared on C/C composite by in-situ reaction. • A two-layered structure was obtained when the coating was oxidized at 1500 °C. • The formation and collapse of bubbles influenced the coating oxidation greatly. • The morphology evolution of oxide scale during oxidation was illuminated. - Abstract: To protect carbon/carbon (C/C) composites against oxidation, zirconium diboride–silicon carbide (ZrB 2 –SiC) coating was prepared by in-situ reaction using ZrC, B 4 C and Si as raw materials. The in-situ ZrB 2 –SiC coated C/C presented good oxidation resistance, whose weight loss was only 0.15% after isothermal oxidation at 1500 °C for 216 h. Microstructure evolution of coating at 1500 °C was studied, revealing a two-layered structure: (1) ZrO 2 (ZrSiO 4 ) embedded in SiO 2 -rich glass, and (2) unaffected ZrB 2 –SiC. The formation and collapse of bubbles influenced the coating oxidation greatly. A model based on the evolution of oxide scale was proposed to explain the failure mechanism of coating

PEPCK-M expression in mouse liver potentiates, not replaces, PEPCK-C mediated gluconeogenesis

Science.gov (United States)

Méndez-Lucas, Andrés; Duarte, João; Sunny, Nishanth E.; Satapati, Santhosh; He, TianTeng; Fu, Xiaorong; Bermúdez, Jordi; Burgess, Shawn C.; Perales, Jose C.

2013-01-01

Background & Aims Hepatic gluconeogenesis helps maintain systemic energy homeostasis by compensating for discontinuities in nutrient supply. Liver specific deletion of cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) abolishes gluconeogenesis from mitochondrial substrates, deregulates lipid metabolism and affects TCA cycle. While, mouse liver almost exclusively expresses PEPCK-C, humans equally present a mitochondrial isozyme (PEPCK-M). Despite clear relevance to human physiology, the role of PEPCK-M and its gluconeogenic potential remain unknown. Here, we test the significance of PEPCK-M in gluconeogenesis and TCA cycle function in liver-specific PEPCK-C knockout and WT mice. Methods The effects of the overexpression of PEPCK-M were examined by a combination of tracer studies and molecular biology techniques. Partial PEPCK-C re-expression was used as a positive control. Metabolic fluxes were evaluated in isolated livers by NMR using 2H and 13C tracers. Gluconeogenic potential, together with metabolic profiling, were investigated in vivo and in primary hepatocytes. Results PEPCK-M expression partially rescued defects in lipid metabolism, gluconeogenesis and TCA cycle function impaired by PEPCK-C deletion, while ~10% re-expression of PEPCK-C normalized most parameters. When PEPCK-M was expressed in the presence of PEPCK-C, the mitochondrial isozyme amplified total gluconeogenic capacity, suggesting autonomous regulation of oxaloacetate to phosphoenolpyruvate fluxes by the individual isoforms. Conclusions We conclude that PEPCK-M has gluconeogenic potential per se, and cooperates with PEPCK-C to adjust gluconeogenic/TCA flux to changes in substrate or energy availability, hinting at a role in the regulation of glucose and lipid metabolism in human liver. PMID:23466304

In situ measurement of magnesium carbonate formation from CO2 using static high-pressure and -temperature 13C NMR.

Science.gov (United States)

Surface, J Andrew; Skemer, Philip; Hayes, Sophia E; Conradi, Mark S

2013-01-02

We explore a new in situ NMR spectroscopy method that possesses the ability to monitor the chemical evolution of supercritical CO(2) in relevant conditions for geological CO(2) sequestration. As a model, we use the fast reaction of the mineral brucite, Mg(OH)(2), with supercritical CO(2) (88 bar) in aqueous conditions at 80 °C. The in situ conversion of CO(2) into metastable and stable carbonates is observed throughout the reaction. After more than 58 h of reaction, the sample was depressurized and analyzed using in situ Raman spectroscopy, where the laser was focused on the undisturbed products through the glass reaction tube. Postreaction, ex situ analysis was performed on the extracted and dried products using Raman spectroscopy, powder X-ray diffraction, and magic-angle spinning (1)H-decoupled (13)C NMR. These separate methods of analysis confirmed a spatial dependence of products, possibly caused by a gradient of reactant availability, pH, and/or a reaction mechanism that involves first forming hydroxy-hydrated (basic, hydrated) carbonates that convert to the end-product, anhydrous magnesite. This carbonation reaction illustrates the importance of static (unmixed) reaction systems at sequestration-like conditions.

In-situ determination of the effective absorbance of thin μc-Si:H layers growing on rough ZnO:Al

Directory of Open Access Journals (Sweden)

Meier Matthias

2013-10-01

Full Text Available In this study optical transmission measurements were performed in-situ during the growth of microcrystalline silicon (μc-Si:H layers by plasma enhanced chemical vapor deposition (PECVD. The stable plasma emission was used as light source. The effective absorption coefficient of the thin μc-Si:H layers which were deposited on rough transparent conductive oxide (TCO surfaces was calculated from the transient transmission signal. It was observed that by increasing the surface roughness of the TCO, the effective absorption coefficient increases which can be correlated to the increased light scattering effect and thus the enhanced light paths inside the silicon. A correlation between the in-situ determined effective absorbance of the μc-Si:H absorber layer and the short-circuit current density of μc-Si:H thin-film silicon solar cells was found. Hence, an attractive technique is demonstrated to study, on the one hand, the absorbance and the light trapping in thin films depending on the roughness of the substrate and, on the other hand, to estimate the short-circuit current density of thin-film solar cells in-situ, which makes the method interesting as a process control tool.

Determining pH at elevated pressure and temperature using in situ ¹³C NMR.

Science.gov (United States)

Surface, J Andrew; Wang, Fei; Zhu, Yanzhe; Hayes, Sophia E; Giammar, Daniel E; Conradi, Mark S

2015-02-03

We have developed an approach for determining pH at elevated pressures and temperatures by using (13)C NMR measurements of inorganic carbon species together with a geochemical equilibrium model. The approach can determine in situ pH with precision better than 0.1 pH units at pressures, temperatures, and ionic strengths typical of geologic carbon sequestration systems. A custom-built high pressure NMR probe was used to collect (13)C NMR spectra of (13)C-labeled CO2 reactions with NaOH solutions and Mg(OH)2 suspensions at pressures up to 107 bar and temperatures of 80 °C. The quantitative nature of NMR spectroscopy allows the concentration ratio [CO2]/[HCO3(-)] to be experimentally determined. This ratio is then used with equilibrium constants calculated for the specific pressure and temperature conditions and appropriate activity coefficients for the solutes to calculate the in situ pH. The experimentally determined [CO2]/[HCO3(-)] ratios agree well with the predicted values for experiments performed with three different concentrations of NaOH and equilibration with multiple pressures of CO2. The approach was then applied to experiments with Mg(OH)2 slurries in which the change in pH could track the dissolution of CO2 into solution, rapid initial Mg(OH)2 dissolution, and onset of magnesium carbonate precipitation.

Effects of phosphoenolpyruvate carboxylase desensitization on glutamic acid production in Corynebacterium glutamicum ATCC 13032.

Science.gov (United States)

Wada, Masaru; Sawada, Kazunori; Ogura, Kotaro; Shimono, Yuta; Hagiwara, Takuya; Sugimoto, Masakazu; Onuki, Akiko; Yokota, Atsushi

2016-02-01

Phosphoenolpyruvate carboxylase (PEPC) in Corynebacterium glutamicum ATCC13032, a glutamic-acid producing actinobacterium, is subject to feedback inhibition by metabolic intermediates such as aspartic acid and 2-oxoglutaric acid, which implies the importance of PEPC in replenishing oxaloacetic acid into the TCA cycle. Here, we investigated the effects of feedback-insensitive PEPC on glutamic acid production. A single amino-acid substitution in PEPC, D299N, was found to relieve the feedback control by aspartic acid, but not by 2-oxoglutaric acid. A simple mutant, strain R1, having the D299N substitution in PEPC was constructed from ATCC 13032 using the double-crossover chromosome replacement technique. Strain R1 produced glutamic acid at a concentration of 31.0 g/L from 100 g/L glucose in a jar fermentor culture under biotin-limited conditions, which was significantly higher than that of the parent, 26.0 g/L (1.19-fold), indicative of the positive effect of desensitized PEPC on glutamic acid production. Another mutant, strain DR1, having both desensitized PEPC and PYK-gene deleted mutations, was constructed in a similar manner using strain D1 with a PYK-gene deleted mutation as the parent. This mutation had been shown to enhance glutamic acid production in our previous study. Although marginal, strain D1 produced higher glutamic acid, 28.8 g/L, than ATCC13032 (1.11-fold). In contrast, glutamic acid production by strain DR-1 was elevated up to 36.9 g/L, which was 1.42-fold higher than ATCC13032 and significantly higher than the other three strains. The results showed a synergistic effect of these two mutations on glutamic acid production in C. glutamicum. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

(001) 3C SiC/Ni contact interface: In situ XPS observation of annealing induced Ni_2Si formation and the resulting barrier height changes

International Nuclear Information System (INIS)

Tengeler, Sven; Kaiser, Bernhard; Chaussende, Didier; Jaegermann, Wolfram

2017-01-01

Highlights: • Schottky behavior (Φ_B = 0.41 eV) and Fermi level pining were found pre annealing. • Ni_2Si formation was confirmed for 5 min at 850 °C. • 3C/Ni_2Si Fermi level alignment is responsible for ohmic contact behavior. • Wet chemical etching (Si–OH/C–H termination) does not impair Ni_2Si formation. - Abstract: The electronic states of the (001) 3C SiC/Ni interface prior and post annealing are investigated via an in situ XPS interface experiment, allowing direct observation of the induced band bending and the transformation from Schottky to ohmic behaviour for the first time. A single domain (001) 3C SiC sample was prepared via wet chemical etching. Nickel was deposited on the sample in multiple in situ deposition steps via RF sputtering, allowing observation of the 3C SiC/Ni interface formation. Over the course of the experiments, an upward band bending of 0.35 eV was observed, along with defect induced Fermi level pinning. This indicates a Schottky type contact behaviour with a barrier height of 0.41 eV. The subsequent annealing at 850 °C for 5 min resulted in the formation of a Ni_2Si layer and a reversal of the band bending to 0.06 eV downward. Thus explaining the ohmic contact behaviour frequently reported for annealed n-type 3C SiC/Ni contacts.

Phosphoenolpyruvate phosphotransferase system components positively regulate Klebsiella biofilm formation

Directory of Open Access Journals (Sweden)

Yu-Tze Horng

2018-04-01

Full Text Available Background/Purpose: Klebsiella pneumoniae is one of the leading causes of device-related infections (DRIs, which are associated with attachment of bacteria to these devices to form a biofilm. The latter is composed of not only bacteria but also extracellular polymeric substances (EPSes consisting of extracellular DNAs, polysaccharides, and other macromolecules. The phosphoenolpyruvate (PEP:carbohydrate phosphotransferase system (PTS regulates diverse processes of bacterial physiology. In the genome of K. pneumoniae MGH 78578, we found an uncharacterized enzyme II complex homolog of PTS: KPN00353 (EIIA homolog, KPN00352 (EIIB homolog, and KPN00351 (EIIC homolog. The aim of this study was to characterize the potential physiological role of KPN00353, KPN00352, and KPN00351 in biofilm formation by K. pneumoniae. Methods/Results: We constructed the PTS mutants and recombinant strains carrying the gene(s of PTS. The recombinant K. pneumoniae strain overexpressing KPN00353–KPN00352–KPN00351 produced more extracellular matrix than did the vector control according to transmission and scanning electron microscopy. Judging by quantification of biofilm formation, of extracellular DNA (eDNA, and of capsular polysaccharide, the recombinant strain overexpressing KPN00353-KPN00352-KPN00351 produced more biofilm and capsular polysaccharide after overnight culture and more eDNA in the log phase as compared to the vector control. Conclusion: The genes, KPN00353–KPN00352–KPN00351, encode a putative enzyme II complex in PTS and positively regulate biofilm formation by enhancing production of eDNA and capsular polysaccharide in K. pneumoniae. Five proteins related to chaperones, to the citric acid cycle, and to quorum sensing are upregulated by the KPN00353–KPN00352–KPN00351 system. Keywords: Klebsiella, PTS, Biofilm, eDNA, Polysaccharide

Structure, thermal and mechanical properties of in situ Al-based metal matrix composite reinforced with Al2O3 and TiC submicron particles

International Nuclear Information System (INIS)

Yu Peng; Mei Zhi; Tjong, S.C.

2005-01-01

We report herein the structure and characterization of in situ Al-based metal matrix composites (MMCs) prepared from the Al-10 wt.% TiO 2 and Al-10 wt.% TiO 2 -1.5 wt.% C systems via hot isostatic pressing (HIP) at 1000 deg C and 100 MPa. The structure, morphology and thermal behavior of HIPed samples were studied by means of the X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results indicated that fined Al 2 O 3 particles and large intermetallic Al 3 Ti plates were in situ formed in the Al-10 wt.% TiO 2 sample during HIPing. However, the introduction of C to the Al-TiO 2 system was beneficial to eliminate large intermetallic Al 3 Ti plates. In this case, Al 2 O 3 and TiC submicron particles were in situ formed in the Al-10 wt.% TiO 2 -1.5 wt.% C sample. Three-point-bending test showed that the strength and the strain-at-break of the HIPed Al-10 wt.% TiO 2 -1.5 wt.% C sample were significantly higher than those of its Al-10 wt.% TiO 2 counterpart. The improvement was derived from the elimination of bulk Al 3 Ti intermetallic plates and from the formation of TiC submicron particles. DSC measurements and thermodynamic analyses were carried out to reveal the reaction formation mechanisms of in situ reinforcing phases. The DSC results generally correlated well with the theoretical predictions. Finally, the correlation between the structure-property relationships of in situ composites is discussed

Synthesis of LiFePO4/C cathode material from ferric oxide and organic lithium salts

International Nuclear Information System (INIS)

Shi Zhongqi; Huang Ming; Huai Yongjian; Lin Ziji; Yang Kerun; Hu Xuebu; Deng Zhenghua

2011-01-01

Research highlights: → LiFePO 4 can be synthesized from Fe 2 O 3 by a sequence of free-radical reactions. → Organic lithium salts can avoid the composition segregation of the precursor. → Low cost ferric oxide and environmentally friendly distilled water are used. - Abstract: LiFePO 4 /C cathode material has been simply synthesized via a modified in situ solid-state reaction route using the raw materials of Fe 2 O 3 , NH 4 H 2 PO 4 , Li 2 C 2 O 4 and lithium polyacrylate (PAALi). The sintering temperature of LiFePO 4 /C precursor is studied by thermo-gravimetric (TG)/differential thermal analysis (DTA). The physical properties of LiFePO 4 /C are then investigated through analysis using by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and the electrochemical properties are investigated by electrochemical impedance spectra (EIS), cyclic voltammogram (CV) and constant current charge/discharge test. The LiFePO 4 /C composite with the particle size of ∼200 nm shows better discharge capacity (156.4 mAh g -1 ) than bare LiFePO 4 (52.3 mAh g -1 ) at 0.2 C due to the improved electronic conductivity which is demonstrated by EIS. The as-prepared LiFePO 4 /C through this method also shows excellent high-rate characteristic and cycle performance. The initial discharge capacity of the sample is 120.5 mAh g -1 and the capacity retention rate is 100.6% after 50 cycles at 5 C rate. The results prove that the using of organic lithium salts can obtain a high performance LiFePO 4 /C composite.

In situ deuterium inventory measurements of a-C:D layers on tungsten in TEXTOR by laser induced ablation spectroscopy

International Nuclear Information System (INIS)

Gierse, N; Brezinsek, S; Coenen, J W; Huber, A; Laengner, M; Möller, S; Nonhoff, M; Philipps, V; Pospieszczyk, A; Schweer, B; Sergienko, G; Xiao, Q; Zlobinski, M; Samm, U; Giesen, T F

2014-01-01

Laser induced ablation spectroscopy (LIAS) is a diagnostic to provide temporally and spatially resolved in situ measurements of tritium retention and material migration in order to characterize the status of the first wall in future fusion devices. In LIAS, a ns-laser pulse ablates the first nanometres of the first wall plasma-facing components into the plasma edge. The resulting line radiation by plasma excitation is observed by spectroscopy. In the case of the full ionizing plasma and with knowledge of appropriate photon efficiencies for the corresponding line emission the amount of ablated material can be measured in situ. We present the photon efficiency for the deuterium Balmer α-line resulting from ablation in TEXTOR by performing LIAS on amorphous hydrocarbon (a-C:D) layers deposited on tungsten substrate of thicknesses between 0.1 and 1.1 μm. An experimental inverse photon efficiency of [(D/(XB))] D α (EXP) a-C:D→ LIAS D =75.9±23.4 was determined. This value is a factor 5 larger than predicted values from the ADAS database for atomic injection of deuterium under TEXTOR plasma edge conditions and about twice as high, assuming normal wall recycling and release of molecular deuterium and break-up of D 2 via the molecular ion which is usually observed at the high temperature tokamak edge (T e  > 30 eV). (paper)

In Situ Vitrification Engineering-Scale Test ES-INEL-4 Product Characterization Test Plan

International Nuclear Information System (INIS)

Weidner, J.R.; Stoots, P.R.

1990-06-01

In 1987, the Buried Waste Program (BWP) was established within EG ampersand G Idaho, Inc., the prime contractor at INEL. Following the Environmental Restoration guidelines of the Buried Waste Program, the In Situ Vitrification Program is participating in a Remedial Investigation/Feasibility Study (RI/FS) for permanent disposal of INEL waste, in compliance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). This study was requested and is being funded by the Office of Technology Development of the Idaho Operations Office of DOE (DOE-ID). As part of the RI/FS, an in situ vitrification (ISV) scoping study on the treatability of mixed low-level and mixed transuranic-contaminated waste is being performed to determine the applicability of ISV to remediation of waste at SDA. In examination of the ISV process for applicability to SDA waste, this In Situ Vitrification Engineering-Scale Test ES-INEL-4 Product Characterization Test Plan identifies the following: sampling and analysis strategy; sampling procedures; methods to conduct analyses; equipment; and procedures to ensure data quality. 8 refs., 2 tabs

Effects of Processing Parameters on the Fabrication of in-situ Al/TiC Composites by Thermally Activated Combustion Reaction Process in an Aluminium Melt using Al-TiO_2-C Powder Mixtures

International Nuclear Information System (INIS)

Kim, Hwa-Jung; Lee, Jung-Moo; Cho, Young-Hee; Kim, Jong-Jin; Kim, Su-Hyeon; Lee, Jae-Chul

2012-01-01

A feasible way to fabricate in-situ Al/TiC composites was investigated. An elemental mixture of Al-TiO_2-C pellet was directly added into an Al melt at 800-920°C to form TiC by self-combustion reaction. The addition of CuO initiates the self-combustion reaction to form TiC in 1-2 um at the melt temperature above 850°C. Besides the CuO addition, a diluent element of excess Al plays a significant role in the TiC formation by forming a precursor phase, Al_3Ti. Processing parameters such as CuO content, the amount of excess Al and the melt temperature, have affected the combustion reaction and formation of TiC, and their influences on the microstructures of in-situ Al/TiC composites are examined.

Unraveling the evolutionary history of the phosphoryl-transfer chain of the phosphoenolpyruvate:phosphotransferase system through phylogenetic analyses and genome context

Directory of Open Access Journals (Sweden)

Zúñiga Manuel

2008-05-01

Full Text Available Abstract Background The phosphoenolpyruvate phosphotransferase system (PTS plays a major role in sugar transport and in the regulation of essential physiological processes in many bacteria. The PTS couples solute transport to its phosphorylation at the expense of phosphoenolpyruvate (PEP and it consists of general cytoplasmic phosphoryl transfer proteins and specific enzyme II complexes which catalyze the uptake and phosphorylation of solutes. Previous studies have suggested that the evolution of the constituents of the enzyme II complexes has been driven largely by horizontal gene transfer whereas vertical inheritance has been prevalent in the general phosphoryl transfer proteins in some bacterial groups. The aim of this work is to test this hypothesis by studying the evolution of the phosphoryl transfer proteins of the PTS. Results We have analyzed the evolutionary history of the PTS phosphoryl transfer chain (PTS-ptc components in 222 complete genomes by combining phylogenetic methods and analysis of genomic context. Phylogenetic analyses alone were not conclusive for the deepest nodes but when complemented with analyses of genomic context and functional information, the main evolutionary trends of this system could be depicted. Conclusion The PTS-ptc evolved in bacteria after the divergence of early lineages such as Aquificales, Thermotogales and Thermus/Deinococcus. The subsequent evolutionary history of the PTS-ptc varied in different bacterial lineages: vertical inheritance and lineage-specific gene losses mainly explain the current situation in Actinobacteria and Firmicutes whereas horizontal gene transfer (HGT also played a major role in Proteobacteria. Most remarkably, we have identified a HGT event from Firmicutes or Fusobacteria to the last common ancestor of the Enterobacteriaceae, Pasteurellaceae, Shewanellaceae and Vibrionaceae. This transfer led to extensive changes in the metabolic and regulatory networks of these bacteria

Photoperiodism and crassulacean acid metabolism : I. Immunological and kinetic evidences for different patterns of phosphoenolpyruvate carboxylase isoforms in photoperiodically inducible and non-inducible Crassulacean acid metabolism plants.

Science.gov (United States)

Brulfert, J; Müller, D; Kluge, M; Queiroz, O

1982-05-01

Plants of Kalanchoe blossfeldiana v. Poelln. Tom Thumb and Sedum morganianum E. Walth. were grown under controlled photoperiodic conditions under either short or long days. Gaz exchange measurements confirmed that in K. blossfeldiana Crassulacean acid metabolism (CAM) was photoperiodically inducible and that S. morganianum performed CAM independently of photoperiod. With K. blossfeldiana, a comparison of catalytic and regulatory properties of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) from short-day and long-day grown plants showed differences, but not with S. morganianum. Ouchterlony double diffusion tests and immunotitration experiments (using a S. morganianum PEPC antibody) established that CAM is induced in K. blossfeldiana-but not in S. morganianum-through the synthesis of a new PEPC isoform; this form shows an immunological behavior different from that prevailing under non-inductive conditions and can be considered as specific for CAM performance.

Structural modifications induced by ion irradiation and temperature in boron carbide B4C

Science.gov (United States)

Victor, G.; Pipon, Y.; Bérerd, N.; Toulhoat, N.; Moncoffre, N.; Djourelov, N.; Miro, S.; Baillet, J.; Pradeilles, N.; Rapaud, O.; Maître, A.; Gosset, D.

2015-12-01

Already used as neutron absorber in the current French nuclear reactors, boron carbide (B4C) is also considered in the future Sodium Fast Reactors of the next generation (Gen IV). Due to severe irradiation conditions occurring in these reactors, it is of primary importance that this material presents a high structural resistance under irradiation, both in the ballistic and electronic damage regimes. Previous works have shown an important structural resistance of boron carbide even at high neutron fluences. Nevertheless, the structural modification mechanisms due to irradiation are not well understood. Therefore the aim of this paper is to study structural modifications induced in B4C samples in different damage regimes. The boron carbide pellets were shaped and sintered by using spark plasma sintering method. They were then irradiated in several conditions at room temperature or 800 °C, either by favoring the creation of ballistic damage (between 1 and 3 dpa), or by favoring the electronic excitations using 100 MeV swift iodine ions (Se ≈ 15 keV/nm). Ex situ micro-Raman spectroscopy and Doppler broadening of annihilation radiation technique with variable energy slow positrons were coupled to follow the evolution of the B4C structure under irradiation.

Effects of low atmospheric CO2 and elevated temperature during growth on the gas exchange responses of C3, C3-C4 intermediate, and C4 species from three evolutionary lineages of C4 photosynthesis.

Science.gov (United States)

Vogan, Patrick J; Sage, Rowan F

2012-06-01

This study evaluates acclimation of photosynthesis and stomatal conductance in three evolutionary lineages of C(3), C(3)-C(4) intermediate, and C(4) species grown in the low CO(2) and hot conditions proposed to favo r the evolution of C(4) photosynthesis. Closely related C(3), C(3)-C(4), and C(4) species in the genera Flaveria, Heliotropium, and Alternanthera were grown near 380 and 180 μmol CO(2) mol(-1) air and day/night temperatures of 37/29°C. Growth CO(2) had no effect on photosynthetic capacity or nitrogen allocation to Rubisco and electron transport in any of the species. There was also no effect of growth CO(2) on photosynthetic and stomatal responses to intercellular CO(2) concentration. These results demonstrate little ability to acclimate to low CO(2) growth conditions in closely related C(3) and C(3)-C(4) species, indicating that, during past episodes of low CO(2), individual C(3) plants had little ability to adjust their photosynthetic physiology to compensate for carbon starvation. This deficiency could have favored selection for more efficient modes of carbon assimilation, such as C(3)-C(4) intermediacy. The C(3)-C(4) species had approximately 50% greater rates of net CO(2) assimilation than the C(3) species when measured at the growth conditions of 180 μmol mol(-1) and 37°C, demonstrating the superiority of the C(3)-C(4) pathway in low atmospheric CO(2) and hot climates of recent geological time.

The evolution of amorphous grain boundaries during in-situ heating experiments in Lu-Mg doped Si3N4

International Nuclear Information System (INIS)

Bhattacharyya, Somnath; Subramaniam, Anandh; Koch, Christoph T.; Cannon, Rowland M.; Ruehle, Manfred

2006-01-01

The presence of 1-2 nm wide intergranular glassy films (IGFs) found in ceramics such as Si 3 N 4 and SiC strongly influences the properties of the material, including its fracture and creep behaviour. It is therefore important to know the evolution of the film as a function of temperature. Experiments, wherein liquid phase sintered Si 3 N 4 samples were quenched from high temperatures, have been carried out before and shown intriguing results. In the current investigation, in-situ heating experiments have been conducted in 120 kV and 400 kV microscopes, in order to separate beam irradiation from temperature effects. Based on the literature, it was expected that no changes would occur to the IGF below 1000 deg. C. However, it was surprising to note that the thickness measured at 950 deg. C was higher than that at room temperature. The correlation in trends observed in both microscopes shows that electron radiation has a minimal contribution to the change in IGF width at 950 deg. C. No change to the thickness was observed when heating up to 650 deg. C. After cooling back to room temperature there is a reduction in the thickness and thus a tendency to regain the original value of the thickness before heating. We conclude from these observations that certain material transport processes could be active at rather low temperatures (for Si 3 N 4 ). Possible mechanisms and sources of artifacts are also discussed

Isomerisation of c4-c6 aldoses with zeolites

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to isomerization of C4-C6 aldoses to their corresponding C4-C6 ketoses. In particular, the invention concerns isomerization of C4-C6 aldoses over solid zeolite catalysts free of any metals other than aluminum, in the presence of suitable solvent(s) at suitable elevated...... temperatures. C6 and C5 aldose sugars such as glucose and xylose, which are available in large amounts from biomass precursors, are isomerized to fructose and xylulose respectively, in a one or two-step process over inexpensive commercially available zeolite catalysts, containing aluminum as the only metal...

Boosting Anaplerotic Reactions by Pyruvate Kinase Gene Deletion and Phosphoenolpyruvate Carboxylase Desensitization for Glutamic Acid and Lysine Production in Corynebacterium glutamicum.

Science.gov (United States)

Yokota, Atsushi; Sawada, Kazunori; Wada, Masaru

In the 1980s, Shiio and coworkers demonstrated using random mutagenesis that the following three phenotypes were effective for boosting lysine production by Corynebacterium glutamicum: (1) low-activity-level citrate synthase (CS L ), (2) phosphoenolpyruvate carboxylase (PEPC) resistant to feedback inhibition by aspartic acid (PEPC R ), and (3) pyruvate kinase (PYK) deficiency. Here, we reevaluated these phenotypes and their interrelationship in lysine production using recombinant DNA techniques.The pyk deletion and PEPC R (D299N in ppc) independently showed marginal effects on lysine production, but both phenotypes synergistically increased lysine yield, demonstrating the importance of PEPC as an anaplerotic enzyme in lysine production. Similar effects were also found for glutamic acid production. CS L (S252C in gltA) further increased lysine yield. Thus, using molecular techniques, the combination of these three phenotypes was reconfirmed to be effective for lysine production. However, a simple CS L mutant showed instabilities in growth and lysine yield.Surprisingly, the pyk deletion was found to increase biomass production in wild-type C. glutamicum ATCC13032 under biotin-sufficient conditions. The mutant showed a 37% increase in growth (based on OD 660 ) compared with the ATCC13032 strain in a complex medium containing 100 g/L glucose. Metabolome analysis revealed the intracellular accumulation of excess precursor metabolites. Thus, their conversion into biomass was considered to relieve the metabolic distortion in the pyk-deleted mutant. Detailed physiological studies of various pyk-deleted mutants also suggested that malate:quinone oxidoreductase (MQO) is important to control both the intracellular oxaloacetic acid (OAA) level and respiration rate. These findings may facilitate the rational use of C. glutamicum in fermentation industries.

Hot pressing of B4C/SiC composites

International Nuclear Information System (INIS)

Sahin, F.C.; Turhan, E.; Yesilcubuk, S.A.; Addemir, O.

2005-01-01

B 4 C/SiC ceramic composites containing 10-20-30 vol % SiC were prepared by hot pressing method. The effect of SiC addition and hot pressing temperature on sintering behaviour and mechanical properties of hot pressed composites were investigated. Microstructures of hot pressed samples were examined by SEM technique. Three different temperatures (2100 deg. C, 2200 deg. C and 2250 deg. C) were used to optimize hot pressing temperature applying 100 MPa pressure under argon atmosphere during the sintering procedure. The highest relative density of 98.44 % was obtained by hot pressing at 2250 deg. C. However, bending strengths of B 4 C/SiC composite samples were lower than monolithic B 4 C in all experimental conditions. (authors)

Hollow-Cuboid Li3VO4/C as High-Performance Anodes for Lithium-Ion Batteries.

Science.gov (United States)

Zhang, Changkun; Liu, Chaofeng; Nan, Xihui; Song, Huanqiao; Liu, Yaguang; Zhang, Cuiping; Cao, Guozhong

2016-01-13

Li3VO4 has been demonstrated to be a promising anode material for lithium-ion batteries with a low, safe voltage and large capacity. However, its poor electronic conductivity hinders its practical application particularly at a high rate. This work reports that Li3VO4 coated with carbon was synthesized by a one-pot, two-step method with F127 ((PEO)100-(PPO)65-(PEO)100) as both template and carbon source, yielding a microcuboid structure. The resulting Li3VO4/C cuboid shows a stable capacity of 415 mAh g(-1) at 0.5 C and excellent capacity stability at high rates (e.g., 92% capacity retention after 1000 cycles at 10 C = 4 A g(-1)). The lithiation/delithiation process of Li3VO4/C was studied by ex situ X-ray diffraction and Raman spectroscopy, which confirmed that Li3VO4/C underwent a reversible intercalation reaction during discharge/charge processes. The excellent electrochemical performance is attributed largely to the unique microhollow structure. The voids inside hollow structure can not only provide more space to accommodate volume change during discharge/charge processes but also allow the lithium ions insertion and extraction from both outside and inside the hollow structure with a much larger surface area or more reaction sites and shorten the lithium ions diffusion distance, which leads to smaller overpotential and faster reaction kinetics. Carbon derived from F127 through pyrolysis coats Li3VO4 conformably and thus offers good electrical conduction. The results in this work provide convincing evidence that the significant potential of hollow-cuboid Li3VO4/C for high-power batteries.

Strategies to lower greenhouse gas level by rice agriculture | Hsu ...

African Journals Online (AJOL)

The transgenic rice (basically a C3 plant) harboring C4 photosynthetic genes phosphoenolpyruvate carboxylase (PEP) carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) has been showed to increased photosynthetic capacity and efficiency of carbon dioxide assimilation. However, many drawbacks that is, ...

On the ex situ and in situ doping of refractory Ta by pulsed laser ablation

Energy Technology Data Exchange (ETDEWEB)

Lin, Y.L.; Lin, S.S.; Shen, P. [National Sun Yat-sen University, Department of Materials and Optoelectronic Science, Kaohsiung, Taiwan (China); Chen, S. [I-Shou University, Department of Mechanical and Automation Engineering, Kaohsiung, Taiwan (China)

2017-06-15

Ex situ and in situ doping processes of refractory Ta were accomplished by pulsed laser ablation of bulk Ta in vacuum with C-O-H supply from C-coated collodion film and within tetraethyl orthosilicate (TEOS), respectively. Analytical electron microscopic observations of the resultant particulates and condensates indicated that the former process involved interdiffusion in the condensed state to form two kinds of core-shell structures, i.e., C-O-H doped Ta with α-type (bcc) core and lamellar shell and O-H doped γ-TaC{sub 1-x} with amorphous Ta-C-O-H surrounding, respectively, for potential wear and lubrication applications at high temperatures. In situ TEOS mediation, however, enhanced solute trapping to form Si-C-O-H overdoped α-Ta with significant tetragonality (c/a ratio up to 1.27) and Si-O-H doped γ-TaC{sub 1-x} with {111}{sub γ} twin/fault and occasional epitaxial relationship [ anti 123]{sub α}//[ anti 112]{sub γ}; (121){sub α}//(anti 11 anti 1){sub γ} due to particle coalescence. Such Si-C-O-H mediated Ta particles may have potential optocatalytic applications. (orig.)

(001) 3C SiC/Ni contact interface: In situ XPS observation of annealing induced Ni{sub 2}Si formation and the resulting barrier height changes

Energy Technology Data Exchange (ETDEWEB)

Tengeler, Sven, E-mail: stengeler@surface.tu-darmstadt.de [Institute of Material Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Univ. Grenoble Alpes, CNRS, LMGP, F-38000 Grenoble (France); Kaiser, Bernhard [Institute of Material Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Chaussende, Didier [Univ. Grenoble Alpes, CNRS, LMGP, F-38000 Grenoble (France); Jaegermann, Wolfram [Institute of Material Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany)

2017-04-01

Highlights: • Schottky behavior (Φ{sub B} = 0.41 eV) and Fermi level pining were found pre annealing. • Ni{sub 2}Si formation was confirmed for 5 min at 850 °C. • 3C/Ni{sub 2}Si Fermi level alignment is responsible for ohmic contact behavior. • Wet chemical etching (Si–OH/C–H termination) does not impair Ni{sub 2}Si formation. - Abstract: The electronic states of the (001) 3C SiC/Ni interface prior and post annealing are investigated via an in situ XPS interface experiment, allowing direct observation of the induced band bending and the transformation from Schottky to ohmic behaviour for the first time. A single domain (001) 3C SiC sample was prepared via wet chemical etching. Nickel was deposited on the sample in multiple in situ deposition steps via RF sputtering, allowing observation of the 3C SiC/Ni interface formation. Over the course of the experiments, an upward band bending of 0.35 eV was observed, along with defect induced Fermi level pinning. This indicates a Schottky type contact behaviour with a barrier height of 0.41 eV. The subsequent annealing at 850 °C for 5 min resulted in the formation of a Ni{sub 2}Si layer and a reversal of the band bending to 0.06 eV downward. Thus explaining the ohmic contact behaviour frequently reported for annealed n-type 3C SiC/Ni contacts.

Photosynthetic carbon assimilation in the coccolithophorid Emiliania huxleyi (Haptophyta): Evidence for the predominant operation of the c3 cycle and the contribution of {beta}-carboxylases to the active anaplerotic reaction.

Science.gov (United States)

Tsuji, Yoshinori; Suzuki, Iwane; Shiraiwa, Yoshihiro

2009-02-01

The coccolithophorid Emiliania huxleyi (Haptophyta) is a representative and unique marine phytoplankton species that fixes inorganic carbon by photosynthesis and calci-fication. We examined the initial process of photosynthetic carbon assimilation by analyses of metabolites, enzymes and genes. When the cells were incubated with a radioactive substrate (2.3 mM NaH(14)CO(3)) for 10 s under illumination, 70% of the (14)C was incorporated into the 80% methanol-soluble fraction. Eighty-five and 15% of (14)C in the soluble fraction was incorporated into phosphate esters (P-esters), including the C(3) cycle intermediates and a C(4) compound, aspartate, respectively. A pulse-chase experiment showed that (14)C in P-esters was mainly transferred into lipids, while [(14)C]aspartate, [(14)C]alanine and [(14)C]glutamate levels remained almost constant. These results indicate that the C(3) cycle functions as the initial pathway of carbon assimilation and that beta-carboxylation contributes to the production of amino acids in subsequent metabolism. Transcriptional analysis of beta-carboxylases such as pyruvate carboxylase (PYC), phosphoenolpyruvate carboxylase (PEPC) and phosphoenolpyruvate carboxykinase (PEPCK) revealed that PYC and PEPC transcripts were greatly increased under illumination, whereas the PEPCK transcript decreased remarkably. PEPC activity was higher in light-grown cells than in dark-adapted cells. PYC activity was detected in isolated chloroplasts of light-grown cells. According to analysis of their deduced N-terminal sequence, PYC and PEPC are predicted to be located in the chloroplasts and mitochondria, respectively. These results suggest that E. huxleyi possesses unique carbon assimila-tion mechanisms in which beta-carboxylation by both PYC and PEPC plays important roles in different organelles.

In situ measurement of tritium permeation through stainless steel

Energy Technology Data Exchange (ETDEWEB)

Luscher, Walter G., E-mail: walter.luscher@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); Senor, David J., E-mail: david.senor@pnnl.gov [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); Clayton, Kevin K., E-mail: kevin.clayton@inl.gov [Idaho National Laboratory, 2525 Fremont Ave., Idaho Falls, ID 83415 (United States); Longhurst, Glen R., E-mail: glenlonghurst@suu.edu [Idaho National Laboratory, 2525 Fremont Ave., Idaho Falls, ID 83415 (United States)

2013-06-15

Highlights: ► In situ tritium permeation measurements collected over broad pressure range. ► Test conditions relevant to 316 SS in commercial light water reactors. ► Comparisons between in- and ex-reactor measurements provided. ► Correlation between tritium permeation, temperature, and pressure developed. -- Abstract: The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a {sup 4}He carrier gas mixed with a specified quantity of tritium (T{sub 2}) to yield partial pressures of 0.1, 5, and 50 Pa at 292 °C and 330 °C. In situ tritium permeation measurements were made by passing a He–Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of {sup 3}He to T, was also evaluated by introducing a {sup 4}He carrier gas mixed with {sup 3}He at a partial pressure of 1013 Pa at 330 °C. Less than 3% of the tritium resulting from {sup 3}He transmutation contributed to tritium permeation.

Identifying sources of methane sampled in the Arctic using δ13C in CH4 and Lagrangian particle dispersion modelling.

Science.gov (United States)

Cain, Michelle; France, James; Pyle, John; Warwick, Nicola; Fisher, Rebecca; Lowry, Dave; Allen, Grant; O'Shea, Sebastian; Illingworth, Samuel; Jones, Ben; Gallagher, Martin; Welpott, Axel; Muller, Jennifer; Bauguitte, Stephane; George, Charles; Hayman, Garry; Manning, Alistair; Myhre, Catherine Lund; Lanoisellé, Mathias; Nisbet, Euan

2016-04-01

An airmass of enhanced methane was sampled during a research flight at ~600 m to ~2000 m altitude between the North coast of Norway and Svalbard on 21 July 2012. The largest source of methane in the summertime Arctic is wetland emissions. Did this enhancement in methane come from wetland emissions? The airmass was identified through continuous methane measurements using a Los Gatos fast greenhouse gas analyser on board the UK's BAe-146 Atmospheric Research Aircraft (ARA) as part of the MAMM (Methane in the Arctic: Measurements and Modelling) campaign. A Lagrangian particle dispersion model (the UK Met Office's NAME model) was run backwards to identify potential methane source regions. This was combined with a methane emission inventory to create "pseudo observations" to compare with the aircraft observations. This modelling was used to constrain the δ13C CH4 wetland source signature (where δ13C CH4 is the ratio of 13C to 12C in methane), resulting in a most likely signature of -73‰ (±4‰7‰). The NAME back trajectories suggest a methane source region of north-western Russian wetlands, and -73‰ is consistent with in situ measurements of wetland methane at similar latitudes in Scandinavia. This analysis has allowed us to study emissions from remote regions for which we do not have in situ observations, giving us an extra tool in the determination of the isotopic source variation of global methane emissions.

In situ green synthesis of MnFe_2O_4/reduced graphene oxide nanocomposite and its usage for fabricating high-performance LiMn_1_/_3Fe_2_/_3PO_4/reduced graphene oxide/carbon cathode material for Li-ion batteries

International Nuclear Information System (INIS)

Wu, Kaipeng; Hu, Guorong; Peng, Zhongdong; Cao, Yanbing; Du, Ke

2016-01-01

Highlights: • MnFe_2O_4/rGO was prepared by an in situ green reduction-coprecipitation method. • LiMn_1_/_3Fe_2_/_3PO_4/rGO/C was synthesized by using MnFe_2O_4/rGO as precursor. • Both pyrolytic carbon and rGO could construct an interconnected conductive network. • LiMn_1_/_3Fe_2_/_3PO_4/rGO/C shows excellent electrochemical performance. - Abstract: MnFe_2O_4/reduced graphene oxide nanocomposite (MnFe_2O_4/rGO) has been synthesized via a green reduction-coprecipitation method for the first time, which involved in situ reduction of GO in presence of Fe"2"+ and the ensuing coprecipitation of Fe"3"+ and Mn"2"+ onto the surface of rGO. The resultant MnFe_2O_4/rGO was then employed as the precursor to fabricate LiMn_1_/_3Fe_2_/_3PO_4/reduced graphene oxide/carbon composite (LiMn_1_/_3Fe_2_/_3PO_4/rGO/C) cathode material for Li-ion batteries. The composite consists of homogeneous Mn-Fe distributed LiMn_1_/_3Fe_2_/_3PO_4 with its primary particles (∼200 nm) covered and connected by both pyrolytic carbon and rGO sheets, which could prevent the aggregation of the particles as well as construct an interconnected conductive network for rapid transmission of electrons during charging and discharging process. The fabricated LiMn_1_/_3Fe_2_/_3PO_4/rGO/C can deliver a discharge capacity of 94.8 mAh g"−"1 even at the high rate of 20C, and shows a capacity decay rate of only 6.25% after 900 long-term charge-discharge cycles. Moreover, the proposed synthesis strategy can also be applied to prepare other graphene-decorated multi-component cathode/anode materials for the Li-ion batteries.

A 3d-4f complex constructed by the assembly of a cationic template, [Cu(en){sub 2}]{sup 2+}, and a 3D anionic coordination polymer, [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-}

Energy Technology Data Exchange (ETDEWEB)

Ke, Szu-Yu; Yeh, Chang-Tsung; Wang, Chih-Chieh [Department of Chemistry, Soochow University, Taipei, Taiwan (China); Lee, Gene-Hsiang [Instrumentation Center, National Taiwan University, Taipei, Taiwan (China); Sheu, Hwo-Shuenn [National Synchrotron Radiation Research Center, Hsinchu, Taiwan (China)

2017-05-18

A three-dimensional (3D) 3d-4f complex, [Cu(en){sub 2}][Sm{sub 2}(C{sub 5}O{sub 5})(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 2}].8H{sub 2}O (1) (en = ethylenediamine, C{sub 5}O{sub 5}{sup 2-} = dianion of 4,5-dihydroxycyclopent-4-ene-1,2,3-trione), were prepared via the in-situ ring-opening oxidation reaction of croconate in the presence of the template-directed complex, [Cu(en){sub 2}]{sup 2+} cation. The structural characterization determined by X-ray diffraction determination reveals that the 3D anionic coordination polymer of [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}(C{sub 5}O{sub 5})(H{sub 2}O){sub 2}]{sup 2-} in 1 can be describe in terms of in-plane 2D honeycomb-like [Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}] layered frameworks bridged by oxalate with bis-chelating mode, being mutually interlinked via the bridge of μ{sub 1,2,3,4}-croconate ligands with bis-chelating coordination mode to complete the 3D open framework, which gives rise to 1D channels with pore size of 14.023 x 11.893 Aa (longest atom-atom contact distances) along the b axis. The structure-directing complex, [Cu(en){sub 2}]{sup 2+}, and solvated water molecules are resided into these honeycomb-type hexagonal channels. The thermal stability of 1 was further studied by TGA and in-situ powder X-ray diffraction measurement. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Li4Ti5O12 thin-film electrodes by in-situ synthesis of lithium alkoxide for Li-ion microbatteries

International Nuclear Information System (INIS)

Mosa, J.; Aparicio, M.; Tadanaga, K.; Hayashi, A.; Tatsumisago, M.

2014-01-01

Rechargeable thin-film batteries have recently become the topic of widespread research for use as efficient energy storage devices. Spinel Li 4 Ti 5 O 12 has been considered as one of the most prospective anode materials for Li-ion batteries because of its excellent reversibility and long cycle life. We report here the sol–gel synthesis and coating preparation of spinel thin-film Li 4 Ti 5 O 12 electrodes for Li-ion microbatteries using lithium ethoxide produced in situ that reacts with titanium alkoxide to produce the precursor solution without particle precipitation. This synthesis procedure reduces the thermal treatment to obtain a pure phase at only 700 °C and 15 minutes. The physical and structural characterization of the 300 nm Li 4 Ti 5 O 12 coatings shows a very homogeneous distribution of elements and a pure spinel phase. Galvanostatic discharge-charge tests indicate maximum discharge capacities of 152 mA h g −1 when the material is treated at 700 °C for 15 minutes

Weldability of Al4C3-Al composites via diffusion welding technique

International Nuclear Information System (INIS)

Arik, Halil; Aydin, Mustafa; Kurt, Adem; Turker, Mehmet

2005-01-01

In this study, Al-Al 4 C 3 composites, produced by powder metallurgy in situ techniques, were joined by diffusion welding technique at 250 MPa pressure with various welding temperatures and durations. Microstructures and shear strengths of the joined areas were determined. Al powders were mixed with 2% carbon black and milled in a high energy ball mill (mechanical alloying) for up to 20 h. In order to obtain cylindrical blanks with 10 mm in diameter and 15 mm in height, powders were compacted in a single action press at 1000 MPa. Samples were sintered in Ar atmosphere at 650 deg C and metal matrix composite (MMC) containing 8% Al 4 C 3 particles were produced. Products were then joined to each other by using diffusion welding techniques. Scanning electron microscopy examination was carried out on the welded interfaces and shear tests were conducted to the sample interfaces to find out the effect of welding temperatures and duration on the weldability properties. It was found that high welding temperatures resulted in increase of both joined strength and shear properties. However, increase in welding duration did not make any detectable changes. Results indicated that MMC could be joined by diffusion welding technique successfully with the 88% strength of base material

Tropical Andean and African glacier extent through the Holocene assessed with proglacial in situ 14C and 10Be measurements

Science.gov (United States)

Vickers, A. C.; Shakun, J. D.; Goehring, B. M.; Kelly, M. A.; Jackson, M. S.; Jomelli, V.

2017-12-01

We present measurements of the in situ cosmogenic radionuclides 14C and 10Be from recently exposed proglacial bedrock samples at the margin of the Quelccaya Ice Cap in Peru (n=5) and the Rwenzori mountains in Africa (n=3) to calculate cumulative exposure, burial, and erosion histories at these sites over the Holocene. The Holocene history (11 ka - present) of tropical glaciers gives important context to their observed retreat over the last century, insight into their sensitivity to climate forcing, and constraints on past climate change. Paired in situ 14C/10Be methods are used to exploit the multiple controls on nuclide concentrations and their differing half-lives (5730 years vs 1.38 Myr). In particular, the concentrations of both 14C and 10Be increase with exposure and decrease with glacial erosion; however,14C decreases not only due to glacial erosion, but also in appreciable amounts due to radio-decay during periods of burial as short as 800 years. Our results show similarities at both sites, with moderately high 10Be concentrations but 14C/10Be ratios approximately one-third of the production value, suggesting that both sites experienced several thousand years of exposure followed by burial during the mid-to-late Holocene. Our results are consistent with recently exposed subfossil plant remains at the Quelccaya margin that imply ice extended beyond its current position since 5.2 ka We will also present 10Be ages of several boulders from probable Little Ice Age moraines of the Charquini Sur Glacier in Bolivia (n=2) and Ritacuba Negro Glacier in Colombia (n=4) to better understand the timing of Little Ice Age advances in the tropical Andes.

Constructing Solid-Gas-Interfacial Fenton Reaction over Alkalinized-C3N4 Photocatalyst To Achieve Apparent Quantum Yield of 49% at 420 nm.

Science.gov (United States)

Li, Yunxiang; Ouyang, Shuxin; Xu, Hua; Wang, Xin; Bi, Yingpu; Zhang, Yuanfang; Ye, Jinhua

2016-10-03

Efficient generation of active oxygen-related radicals plays an essential role in boosting advanced oxidation process. To promote photocatalytic oxidation for gaseous pollutant over g-C 3 N 4 , a solid-gas interfacial Fenton reaction is coupled into alkalinized g-C 3 N 4 -based photocatalyst to effectively convert photocatalytic generation of H 2 O 2 into oxygen-related radicals. This system includes light energy as power, alkalinized g-C 3 N 4 -based photocatalyst as an in situ and robust H 2 O 2 generator, and surface-decorated Fe 3+ as a trigger of H 2 O 2 conversion, which attains highly efficient and universal activity for photodegradation of volatile organic compounds (VOCs). Taking the photooxidation of isopropanol as model reaction, this system achieves a photoactivity of 2-3 orders of magnitude higher than that of pristine g-C 3 N 4 , which corresponds to a high apparent quantum yield of 49% at around 420 nm. In-situ electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicate that the notable photoactivity promotion could be ascribed to the collaboration between photocarriers (electrons and holes) and Fenton process to produce abundant and reactive oxygen-related radicals. The strategy of coupling solid-gas interfacial Fenton process into semiconductor-based photocatalysis provides a facile and promising solution to the remediation of air pollution via solar energy.

Comparative Effects of Phosphoenolpyruvate, a Glycolytic Intermediate, as an Organ Preservation Agent with Glucose and N-Acetylcysteine against Organ Damage during Cold Storage of Mouse Liver and Kidney

OpenAIRE

Ishitsuka, Yoichi; Fukumoto, Yusuke; Kondo, Yuki; Irikura, Mitsuru; Kadowaki, Daisuke; Narita, Yuki; Hirata, Sumio; Moriuchi, Hiroshi; Maruyama, Toru; Hamasaki, Naotaka; Irie, Tetsumi

2013-01-01

We evaluated the usefulness of phosphoenolpyruvate (PEP), a glycolytic intermediate with antioxidative and energy supplementation potentials, as an organ preservation agent. Using ex vivo mouse liver and kidney of a static cold storage model, we compared the effects of PEP against organ damage and oxidative stress during cold preservation with those of glucose or N-acetylcysteine (NAC). Lactate dehydrogenase (LDH) leakage, histological changes, and oxidative stress parameters (measured as thi...

In-situ pH measurements and sample analyses in glass-iron-clay systems at 90 deg. C and 150 deg. C

International Nuclear Information System (INIS)

Rozsypal, Christophe; Mosser-Ruck, Regine; Truche, Laurent; Pignatelli, Isabella; Randi, Aurelien; Bartier, Daniele; Cathelineau, Michel; Michau, Nicolas

2012-01-01

Document available in extended abstract form only. The long term repository of long life and high activity radioactive waste consists in the burial of steel overpacks of vitrified waste in a clay-stone. As the natural interstitial fluid of the clay-stone is a potential corrosion enhancer for the containers, the viability of the repository requires previous data acquisition on the interactions between clays, water, metallic iron, and glass. A set of experiments have been performed in autoclaves at 90 deg. C (thermal peak of the site) in order to follow the pH evolution and to characterize fluids with time and solids at the end of the experiments. Another set of experiments at 150 deg. C have also been carried out in order to increase the rates of the involved chemical reactions and mineralogical transformations. The objectives of those two sets of experiments were to measure the in-situ pH, to study how it was influenced by various parameters, such as the presence of glass and/or iron, to estimate the increase of the CO 2 and H 2 pressures, and to analyze gas and liquids taken in the course or at the end of experiments and solids recovered at the end of the experiments. The initial aqueous solution simulating the natural interstitial fluid was made of 22 mM of sodium, 4 mM of calcium, 29.75 mM of chloride, and 0.25 mM of bromide as a tracer. The initial solution/clay mass ratio was 10 for all the experiments, the metallic iron/clay or glass/clay mass ratios were 0.1 or 0. The list of the experiments and their characteristics is given in Table (1). The first results concern the evolution of the in-situ pH during the A90pH experiment and are reported on Figure (1). The measurements started after a 48 hours stabilization time of the pH probe. The pH seemed to tend reaching a plateau after several weeks. (authors)

In-situ preparation of poly(ethylene oxide)/Li3PS4 hybrid polymer electrolyte with good nanofiller distribution for rechargeable solid-state lithium batteries

Science.gov (United States)

Chen, Shaojie; Wang, Junye; Zhang, Zhihua; Wu, Linbin; Yao, Lili; Wei, Zhenyao; Deng, Yonghong; Xie, Dongjiu; Yao, Xiayin; Xu, Xiaoxiong

2018-05-01

Nano-sized fillers in a polymer matrix with good distribution can play a positive role in improving polymer electrolytes in the aspects of ionic conductivity, mechanical property and electrochemical performance of Li-ion cells. Herein, polyethylene oxide (PEO)/Li3PS4 hybrid polymer electrolyte is prepared via a new in-situ approach. The ionic conductivities of the novel hybrid electrolytes with variable proportions are measured, and the optimal electrolyte of PEO-2%vol Li3PS4 presents a considerable ionic conductivity of 8.01 × 10-4 S cm-1 at 60 °C and an electrochemical window up to 5.1 V. The tests of DSC and EDXS reveal that the Li3PS4 nanoparticles with better distribution, as active fillers scattering in the PEO, exhibit a positive effect on the transference of lithium ion and electrochemical interfacial stabilities. Finally, the assembled solid-state LiFePO4/Li battery presents a decent cycling performance (80.9% retention rate after 325 cycles at 60 °C) and excellent rate capacities with 153, 143, 139 and 127 mAh g-1 at the discharging rate of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C. It is fully proved that it is an advanced strategy to preparing the new organic/inorganic hybrid electrolytes for lithium-ion batteries applications.

Human cDNA mapping using fluorescence in situ hybridization

Energy Technology Data Exchange (ETDEWEB)

Korenberg, J.R.

1993-03-04

Genetic mapping is approached using the techniques of high resolution fluorescence in situ hybridization (FISH). This technology and the results of its application are designed to rapidly generate whole genome as tool box of expressed sequence to speed the identification of human disease genes. The results of this study are intended to dovetail with and to link the results of existing technologies for creating backbone YAC and genetic maps. In the first eight months, this approach generated 60--80% of the expressed sequence map, the remainder expected to be derived through more long-term, labor-intensive, regional chromosomal gene searches or sequencing. The laboratory has made significant progress in the set-up phase, in mapping fetal and adult brain and other cDNAs, in testing a model system for directly linking genetic and physical maps using FISH with small fragments, in setting up a database, and in establishing the validity and throughput of the system.

Synthesis and structural characterization of Al4SiC4-homeotypic aluminum silicon oxycarbide, [Al4.4Si0.6][O1.0C2.0]C

International Nuclear Information System (INIS)

Kaga, Motoaki; Iwata, Tomoyuki; Nakano, Hiromi; Fukuda, Koichiro

2010-01-01

A new quaternary layered oxycarbide, [Al 4.39(5) Si 0.61(5) ] Σ5 [O 1.00(2) C 2.00(2) ] Σ3 C, has been synthesized and characterized by X-ray powder diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). The title compound was found to be hexagonal with space group P6 3 /mmc, Z=2, and unit-cell dimensions a=0.32783(1) nm, c=2.16674(7) nm and V=0.20167(1) nm 3 . The atom ratios Al:Si were determined by EDX, and the initial structural model was derived by the direct methods. The final structural model showed the positional disordering of one of the three types of Al/Si sites. The maximum-entropy methods-based pattern fitting (MPF) method was used to confirm the validity of the split-atom model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The reliability indices calculated from the MPF were R wp =3.73% (S=1.20), R p =2.94%, R B =1.04% and R F =0.81%. The crystal was an inversion twin. Each twin-related individual was isostructural with Al 4 SiC 4 (space group P6 3 mc, Z=2). - Graphical abstract: A new oxycarbide discovered in the Al-Si-O-C system, Al 4 SiC 4 -homeotypic [Al 4.4 Si 0.6 ][O 1.0 C 2.0 ]C. The crystal is an inversion twin, and hence the structure is represented by a split-atom model. The three-dimensional electron density distributions are determined by the maximum-entropy methods-based pattern fitting, being consistent with the disordered structural model.

Investigation of the fabrication processes of AlGaN/AlN/GaN HEMTs with in situ Si{sub 3}N{sub 4} passivation

Energy Technology Data Exchange (ETDEWEB)

Tomosh, K. N., E-mail: sky77781@mail.ru; Pavlov, A. Yu.; Pavlov, V. Yu.; Khabibullin, R. A.; Arutyunyan, S. S.; Maltsev, P. P. [Russian Academy of Sciences, Institute of Ultra-High-Frequency Semiconductor Electronics (Russian Federation)

2016-10-15

The optimum mode of the in situ plasma-chemical etching of a Si{sub 3}N{sub 4} passivating layer in C{sub 3}F{sub 8}/O{sub 2} medium is chosen for the case of fabricating AlGaN/AlN/GaN HEMTs. It is found that a bias of 40–50 V at a high-frequency electrode provides anisotropic etching of the insulator through a resist mask and introduces no appreciable radiation-induced defects upon overetching of the insulator films in the region of gate-metallization formation. To estimate the effect of in situ Si{sub 3}N{sub 4} growth together with the heterostructure in one process on the AlGaN/AlN/GaN HEMT characteristics, transistors with gates without the insulator and with gates through Si{sub 3}N{sub 4} slits are fabricated. The highest drain current of the AlGaN/AlN/GaN HEMT at 0 V at the gate is shown to be 1.5 times higher in the presence of Si{sub 3}N{sub 4} than without it.

A comparison study on the densification behavior and mechanical properties of gelcast vs conventionally formed B4C sintered conventionally and by microwaves

International Nuclear Information System (INIS)

Menchhofer, P.A.; Kiggans, J.O.; Morrow, M.S.; Schechter, D.E.

1996-01-01

The utilization of microwave energy for reaching high temperatures necessary to densify B 4 C powder is compared with conventional means of sintering by evaluating the mechanical properties after densification. Microwave energy has been shown to be an effective means for achieving high sintered densities, even though temperatures of ∼ 2,250 C are required. In this study, green preforms of B 4 C specimens were sintered by both conventional and microwave heating. This study also utilized an advanced forming method called ''Gelcasting'' developed at ORNL. Gelcasting is a fluid forming process whereby high solids suspensions of powders containing dissolved monomers are cast into a mold, then polymerized or ''gelled'' in situ. This investigation compares microstructures and mechanical properties of both Gelcast B 4 C and ''conventionally'' die-pressed B 4 C. The microstructures and final mechanical properties of B 4 C specimens are discussed

Synthesis of LiFePO{sub 4}/C cathode material from ferric oxide and organic lithium salts

Energy Technology Data Exchange (ETDEWEB)

Shi Zhongqi; Huang Ming [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Huai Yongjian [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); China Aviation Lithium Battery Co., Ltd, Luoyang, Henan 471003 (China); Lin Ziji; Yang Kerun [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Hu Xuebu [Department of Chemistry and Materials, Sichuan Normal University, Chengdu, Sichuan 610068 (China); Zhongke Laifang Power Science and Technology Co., Ltd., Chengdu, Sichuan 610041 (China); Deng Zhenghua, E-mail: zhdeng@cioc.ac.c [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan 610041 (China); Graduate School of Chinese Academy of Sciences, Beijing, 100039 (China); Zhongke Laifang Power Science and Technology Co., Ltd., Chengdu, Sichuan 610041 (China)

2011-04-15

Research highlights: {yields} LiFePO{sub 4} can be synthesized from Fe{sub 2}O{sub 3} by a sequence of free-radical reactions. {yields} Organic lithium salts can avoid the composition segregation of the precursor. {yields} Low cost ferric oxide and environmentally friendly distilled water are used. - Abstract: LiFePO{sub 4}/C cathode material has been simply synthesized via a modified in situ solid-state reaction route using the raw materials of Fe{sub 2}O{sub 3}, NH{sub 4}H{sub 2}PO{sub 4}, Li{sub 2}C{sub 2}O{sub 4} and lithium polyacrylate (PAALi). The sintering temperature of LiFePO{sub 4}/C precursor is studied by thermo-gravimetric (TG)/differential thermal analysis (DTA). The physical properties of LiFePO{sub 4}/C are then investigated through analysis using by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and the electrochemical properties are investigated by electrochemical impedance spectra (EIS), cyclic voltammogram (CV) and constant current charge/discharge test. The LiFePO{sub 4}/C composite with the particle size of {approx}200 nm shows better discharge capacity (156.4 mAh g{sup -1}) than bare LiFePO{sub 4} (52.3 mAh g{sup -1}) at 0.2 C due to the improved electronic conductivity which is demonstrated by EIS. The as-prepared LiFePO{sub 4}/C through this method also shows excellent high-rate characteristic and cycle performance. The initial discharge capacity of the sample is 120.5 mAh g{sup -1} and the capacity retention rate is 100.6% after 50 cycles at 5 C rate. The results prove that the using of organic lithium salts can obtain a high performance LiFePO{sub 4}/C composite.

Luminescent lanthanide coordination polymers synthesized via in-situ hydrolysis of dimethyl-3,4-furandicarboxylate

International Nuclear Information System (INIS)

Greig, Natalie E.; Einkauf, Jeffrey D.; Clark, Jessica M.; Corcoran, Eric J.; Karram, Joseph P.; Kent, Charles A.; Eugene, Vadine E.; Chan, Benny C.; Lill, Daniel T. de

2015-01-01

Dimethyl-3,4-furandicarboxylate undergoes hydrolysis under hydrothermal conditions with lanthanide (Ln) ions to form two-dimensional coordination polymers, [Ln(C 6 H 2 O 5 )(C 6 H 3 O 5 )(H 2 O)] n (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The resulting materials exhibit luminescent properties with quantum yields and lifetimes for the Eu(III) and Tb(III) compounds of 1.1±0.3% and 0.387±0.0001 ms, and 3.3±0.8% and 0.769±0.006 ms, respectively. Energy values for the singlet and triplet states were determined for dimethyl-3,4-furandicarboxylate and 3,4-furandicarboxylic acid. Excited state dynamics and structural features are examined to explicate the reported quantum yields. A series of other FDC structures is briefly presented. - Graphical abstract: A new two-dimensional coordination polymer derived from the in-situ hydrolysis of a furan dimethyl ester with lanthanide(III) ions was obtained in order to study its photophysical behavior when constructed from trivalent Eu and Tb. Quantum yields, lifetime measurements, and singlet/triplet state energies values were obtained. The nature of the material's excited state dynamics is examined and correlated to its structure in order to explain the overall luminescent efficiency of the system. - Highlights: • A new lanthanide–furandicarboxylate coordination polymer is presented. • Eu and Tb compounds display luminescent properties, albeit with low quantum yields. • Photophysical behavior explained through the compound's triplet state and structure. • Nonradiative deactivation of luminescence through high-energy oscillators was noted. • Molecular modeling of the organic moiety was conducted

Luminescent lanthanide coordination polymers synthesized via in-situ hydrolysis of dimethyl-3,4-furandicarboxylate

Energy Technology Data Exchange (ETDEWEB)

Greig, Natalie E.; Einkauf, Jeffrey D.; Clark, Jessica M.; Corcoran, Eric J.; Karram, Joseph P.; Kent, Charles A.; Eugene, Vadine E. [Department of Chemistry & Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (United States); Chan, Benny C. [Department of Chemistry, The College of New Jersey, 2000 Pennington Road, Ewing, NJ 08628 (United States); Lill, Daniel T. de, E-mail: ddelill@fau.edu [Department of Chemistry & Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (United States)

2015-05-15

Dimethyl-3,4-furandicarboxylate undergoes hydrolysis under hydrothermal conditions with lanthanide (Ln) ions to form two-dimensional coordination polymers, [Ln(C{sub 6}H{sub 2}O{sub 5})(C{sub 6}H{sub 3}O{sub 5})(H{sub 2}O)]{sub n} (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The resulting materials exhibit luminescent properties with quantum yields and lifetimes for the Eu(III) and Tb(III) compounds of 1.1±0.3% and 0.387±0.0001 ms, and 3.3±0.8% and 0.769±0.006 ms, respectively. Energy values for the singlet and triplet states were determined for dimethyl-3,4-furandicarboxylate and 3,4-furandicarboxylic acid. Excited state dynamics and structural features are examined to explicate the reported quantum yields. A series of other FDC structures is briefly presented. - Graphical abstract: A new two-dimensional coordination polymer derived from the in-situ hydrolysis of a furan dimethyl ester with lanthanide(III) ions was obtained in order to study its photophysical behavior when constructed from trivalent Eu and Tb. Quantum yields, lifetime measurements, and singlet/triplet state energies values were obtained. The nature of the material's excited state dynamics is examined and correlated to its structure in order to explain the overall luminescent efficiency of the system. - Highlights: • A new lanthanide–furandicarboxylate coordination polymer is presented. • Eu and Tb compounds display luminescent properties, albeit with low quantum yields. • Photophysical behavior explained through the compound's triplet state and structure. • Nonradiative deactivation of luminescence through high-energy oscillators was noted. • Molecular modeling of the organic moiety was conducted.

1-Butyl-3-methylimidazolium hydrogen sulfate catalyzed in-situ transesterification of Nannochloropsis to fatty acid methyl esters

International Nuclear Information System (INIS)

Sun, Yingqiang; Cooke, Peter; Reddy, Harvind K.; Muppaneni, Tapaswy; Wang, Jun; Zeng, Zheling; Deng, Shuguang

2017-01-01

Highlights: • [Bmim][HSO_4] catalyzed in-situ transesterification of wet algae. • [Bmim][HSO_4] served as both effective solvent and excellent acid catalyst. • Proposed a mechanism for [Bmim][HSO_4] catalyzed in-situ transesterification. • Identified cell walls and lipid droplets in algae using confocal imaging tests. • Obtained crude biodiesel yield about 95% in 30 min at 200 °C. - Abstract: 1-Butyl-3-methylimidazolium hydrogen sulfate ([Bmim][HSO_4]) is used as a solvent and an acid catalyst for in-situ extractive transesterification of wet Nannochloropsis with methanol. The reaction is supposed to be a five-step process: (1) wet algae cell wall dissolves in ionic liquid at reaction temperatures; (2) hydrogen ions and sulfate ions release from the ionization of HSO_4"−. The hydrogen ions (H"+) act as catalysts for accelerating the reactive extraction of triglyceride from wet Nannochloropsis; (3) hydrogen ions and methanol molecules transfer from bulk to active site of cells without passing through cell wall that is dissolved by ionic liquid; (4) in-situ transesterification of lipid (mainly triglycerides) with methanol; and (5) products transfer from inside of algae cells to outside of cells. The crude biodiesel yield of [Bmim][HSO_4] catalyzed in-situ transesterification is about 95.28% at reaction temperature of 200 °C, reaction time of 30 min, mass ratio of [Bmim][HSO_4] to wet Nannochloropsis of 0.9:1, and a mass ratio of methanol to wet algae of 3:1. It decreases to 81.23% after [Bmim][HSO_4] is recycled for 4 times, which indicates that [Bmim][HSO_4] catalyzed in-situ transesterification is an economic approach for biodiesel production from wet algae.

Mg doped Li2FeSiO4/C nanocomposites synthesized by the solvothermal method for lithium ion batteries.

Science.gov (United States)

Kumar, Ajay; Jayakumar, O D; Jagannath; Bashiri, Parisa; Nazri, G A; Naik, Vaman M; Naik, Ratna

2017-10-14

A series of porous Li 2 Fe 1-x Mg x SiO 4 /C (x = 0, 0.01, 0.02, 0.04) nanocomposites (LFS/C, 1Mg-LFS/C, 2Mg-LFS and 4Mg-LFS/C) have been synthesized via a solvo-thermal method using the Pluronic P123 polymer as an in situ carbon source. Rietveld refinement of the X-ray diffraction data of Li 2 Fe 1-x Mg x SiO 4 /C composites confirms the formation of the monoclinic P2 1 structure of Li 2 FeSiO 4 . The addition of Mg facilitates the growth of impurity-free Li 2 FeSiO 4 with increased crystallinity and particle size. Despite having the same percentage of carbon content (∼15 wt%) in all the samples, the 1Mg-LFS/C nanocomposite delivered the highest initial discharge capacity of 278 mA h g -1 (∼84% of the theoretical capacity) at the C/30 rate and also exhibited the best rate capability and cycle stability (94% retention after 100 charge-discharge cycles at 1C). This is attributed to its large surface area with a narrow pore size distribution and a lower charge transfer resistance with enhanced Li-ion diffusion coefficient compared to other nanocomposites.

A click chemistry approach to glycomimetics: Michael addition of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose to 4-deoxy-1,2-O-isopropylidene-L-glycero-pent-4-enopyranos-3-ulose--a convenient route to novel 4-deoxy-(1-->5)-5-C-thiodisaccharides.

Science.gov (United States)

Witczak, Zbigniew J; Lorchak, David; Nguyen, Nguyen

2007-09-03

The base catalyzed conjugate Michael addition of the 1-thiosugar, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranose, 1, to a new highly reactive enone 4-deoxy-1,2-O-isopropylidene-L-glycero-pent-4-enopyranos-3-ulose, 2, proceeds steroselectively with formation of adduct 3 in 94% yield. Convenient stereoselective reduction of the C-3 keto function of 3 with L-Selectride followed by in situ acetylation produces thiodisaccharide 4 in good 82% yield. Cleavage of the 1,2-O-isopropylidene protecting group with p-toluenesulfonic acid in methanol, followed by de-O-acetylation, produced an inseparable anomeric mixture of methyl 4-deoxy-5-C-(beta-D-glucopyranosyl)-thio-alpha/beta-L-ribo-pyranoside 5 in 72% overall yield. This approach constitutes a new general two-step click chemistry route to the previously unknown class of 4-deoxy-(1-->5)-5-C-thiodisaccharides as stable and biologically important glycomimetics.

Identification of Photosynthesis-Associated C4 Candidate Genes through Comparative Leaf Gradient Transcriptome in Multiple Lineages of C3 and C4 Species

Science.gov (United States)

Ding, Zehong; Weissmann, Sarit; Wang, Minghui; Du, Baijuan; Huang, Lei; Wang, Lin; Tu, Xiaoyu; Zhong, Silin; Myers, Christopher; Brutnell, Thomas P.; Sun, Qi; Li, Pinghua

2015-01-01

Leaves of C4 crops usually have higher radiation, water and nitrogen use efficiencies compared to the C3 species. Engineering C4 traits into C3 crops has been proposed as one of the most promising ways to repeal the biomass yield ceiling. To better understand the function of C4 photosynthesis, and to identify candidate genes that are associated with the C4 pathways, a comparative transcription network analysis was conducted on leaf developmental gradients of three C4 species including maize, green foxtail and sorghum and one C3 species, rice. By combining the methods of gene co-expression and differentially co-expression networks, we identified a total of 128 C4 specific genes. Besides the classic C4 shuttle genes, a new set of genes associated with light reaction, starch and sucrose metabolism, metabolites transportation, as well as transcription regulation, were identified as involved in C4 photosynthesis. These findings will provide important insights into the differential gene regulation between C3 and C4 species, and a good genetic resource for establishing C4 pathways in C3 crops. PMID:26465154

Identification of Photosynthesis-Associated C4 Candidate Genes through Comparative Leaf Gradient Transcriptome in Multiple Lineages of C3 and C4 Species.

Science.gov (United States)

Ding, Zehong; Weissmann, Sarit; Wang, Minghui; Du, Baijuan; Huang, Lei; Wang, Lin; Tu, Xiaoyu; Zhong, Silin; Myers, Christopher; Brutnell, Thomas P; Sun, Qi; Li, Pinghua

2015-01-01

Leaves of C4 crops usually have higher radiation, water and nitrogen use efficiencies compared to the C3 species. Engineering C4 traits into C3 crops has been proposed as one of the most promising ways to repeal the biomass yield ceiling. To better understand the function of C4 photosynthesis, and to identify candidate genes that are associated with the C4 pathways, a comparative transcription network analysis was conducted on leaf developmental gradients of three C4 species including maize, green foxtail and sorghum and one C3 species, rice. By combining the methods of gene co-expression and differentially co-expression networks, we identified a total of 128 C4 specific genes. Besides the classic C4 shuttle genes, a new set of genes associated with light reaction, starch and sucrose metabolism, metabolites transportation, as well as transcription regulation, were identified as involved in C4 photosynthesis. These findings will provide important insights into the differential gene regulation between C3 and C4 species, and a good genetic resource for establishing C4 pathways in C3 crops.

Identification of Photosynthesis-Associated C4 Candidate Genes through Comparative Leaf Gradient Transcriptome in Multiple Lineages of C3 and C4 Species.

Directory of Open Access Journals (Sweden)

Zehong Ding

Full Text Available Leaves of C4 crops usually have higher radiation, water and nitrogen use efficiencies compared to the C3 species. Engineering C4 traits into C3 crops has been proposed as one of the most promising ways to repeal the biomass yield ceiling. To better understand the function of C4 photosynthesis, and to identify candidate genes that are associated with the C4 pathways, a comparative transcription network analysis was conducted on leaf developmental gradients of three C4 species including maize, green foxtail and sorghum and one C3 species, rice. By combining the methods of gene co-expression and differentially co-expression networks, we identified a total of 128 C4 specific genes. Besides the classic C4 shuttle genes, a new set of genes associated with light reaction, starch and sucrose metabolism, metabolites transportation, as well as transcription regulation, were identified as involved in C4 photosynthesis. These findings will provide important insights into the differential gene regulation between C3 and C4 species, and a good genetic resource for establishing C4 pathways in C3 crops.

Laser cladding Ni-base composite coating on titanium alloy with pre-placed B4C+NiCoCrAlY

International Nuclear Information System (INIS)

Qingwu Meng; Lin Geng; Zhenzhu Zheng

2005-01-01

Using a CO 2 laser, a process of cladding Ni-base composite coating on Ti6Al4V with pre-placed B 4 C and NiCoCrAlY was studied. A good metallurgical bonding coating without cracks and pores was obtained in reasonable ratio of components and low energy laser process. Morphology and microstructure of the coating were analyzed with OM, XRD, SEM and EDS. It is certain that there was a reaction between B 4 C and Ti during in-situ producing TiB 2 and TiC. The Ni-base composite coating is strengthened with TiB 2 and TiC reinforcement phases. Vickers hardness tester measured that the average microhardness of the coating is HV1200 and it is 3.5 times of the Ti6Al4V substrate. The high hard coating containing several reinforcement phases greatly enhances wear resistance of titanium alloy. (orig.)

Novel RNA hybridization method for the in situ detection of ETV1, ETV4, and ETV5 gene fusions in prostate cancer.

Science.gov (United States)

Kunju, Lakshmi P; Carskadon, Shannon; Siddiqui, Javed; Tomlins, Scott A; Chinnaiyan, Arul M; Palanisamy, Nallasivam

2014-09-01

The genetic basis of 50% to 60% of prostate cancer (PCa) is attributable to rearrangements in E26 transformation-specific (ETS) (ERG, ETV1, ETV4, and ETV5), BRAF, and RAF1 genes and overexpression of SPINK1. The development and validation of reliable detection methods are warranted to classify various molecular subtypes of PCa for diagnostic and prognostic purposes. ETS gene rearrangements are typically detected by fluorescence in situ hybridization and reverse-transcription polymerase chain reaction methods. Recently, monoclonal antibodies against ERG have been developed that detect the truncated ERG protein in immunohistochemical assays where staining levels are strongly correlated with ERG rearrangement status by fluorescence in situ hybridization. However, specific antibodies for ETV1, ETV4, and ETV5 are unavailable, challenging their clinical use. We developed a novel RNA in situ hybridization-based assay for the in situ detection of ETV1, ETV4, and ETV5 in formalin-fixed paraffin-embedded tissues from prostate needle biopsies, prostatectomy, and metastatic PCa specimens using RNA probes. Further, with combined RNA in situ hybridization and immunohistochemistry we identified a rare subset of PCa with dual ETS gene rearrangements in collisions of independent tumor foci. The high specificity and sensitivity of RNA in situ hybridization provides an alternate method enabling bright-field in situ detection of ETS gene aberrations in routine clinically available PCa specimens.

Structural modifications induced by ion irradiation and temperature in boron carbide B{sub 4}C

Energy Technology Data Exchange (ETDEWEB)

Victor, G., E-mail: g.victor@ipnl.in2p3.fr [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69622 Villeurbanne Cedex (France); Pipon, Y.; Bérerd, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69622 Villeurbanne Cedex (France); Institut Universitaire de Technologie (IUT) Lyon-1, Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France); Toulhoat, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69622 Villeurbanne Cedex (France); CEA-DEN, Saclay, 91191 Gif-sur-Yvette (France); Moncoffre, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69622 Villeurbanne Cedex (France); Djourelov, N. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tzarigradsko chaussee blvd, BG-1784 Sofia (Bulgaria); ELI-NP, IFIN-HH, 30 Reactorului Str, MG-6 Bucharest-Magurele (Romania); Miro, S. [CEA-DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Baillet, J. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69622 Villeurbanne Cedex (France); Pradeilles, N.; Rapaud, O.; Maître, A. [SPCTS, UMR CNRS 7315, Centre Européen de la céramique, University of Limoges (France); Gosset, D. [CEA, Saclay, DMN-SRMA-LA2M, 91191 Gif-sur-Yvette (France)

2015-12-15

Already used as neutron absorber in the current French nuclear reactors, boron carbide (B{sub 4}C) is also considered in the future Sodium Fast Reactors of the next generation (Gen IV). Due to severe irradiation conditions occurring in these reactors, it is of primary importance that this material presents a high structural resistance under irradiation, both in the ballistic and electronic damage regimes. Previous works have shown an important structural resistance of boron carbide even at high neutron fluences. Nevertheless, the structural modification mechanisms due to irradiation are not well understood. Therefore the aim of this paper is to study structural modifications induced in B{sub 4}C samples in different damage regimes. The boron carbide pellets were shaped and sintered by using spark plasma sintering method. They were then irradiated in several conditions at room temperature or 800 °C, either by favoring the creation of ballistic damage (between 1 and 3 dpa), or by favoring the electronic excitations using 100 MeV swift iodine ions (S{sub e} ≈ 15 keV/nm). Ex situ micro-Raman spectroscopy and Doppler broadening of annihilation radiation technique with variable energy slow positrons were coupled to follow the evolution of the B{sub 4}C structure under irradiation.

Role of manganese on the grain refining efficiency of AZ91D magnesium alloy refined by Al4C3

International Nuclear Information System (INIS)

Liu Shengfa; Zhang Yuan; Han Hui

2010-01-01

A novel Mg-50% Al 4 C 3 (hereafter in wt.%) master alloy has been developed by powder in situ synthesis process, the role of manganese on the grain refining efficiency of AZ91D magnesium alloy refined by this master alloy has been investigated. X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) results show the existence of Al 4 C 3 particles in this master alloy. After addition of 0.6% Al 4 C 3 or combined addition of 0.6% Al 4 C 3 and 0.27% Mn, the average grain size of AZ91D decreased dramatically from 360 μm to 210 μm, and from 360 μm to130 μm, respectively. However, no further refinement of grain size was achieved with additional amount of Mn exceeding 0.27% for AZ91D alloy refined by 0.6% Al 4 C 3 in the present investigation. Al-C-O-Mn-Fe-rich intermetallic particles with an Al-C-O-rich coating film, often observed in the central region of magnesium grains of the AZ91D alloy treated by the combination of Al 4 C 3 and Mn, are proposed to be the potent nucleating substrates for primary α-Mg.

Microbeam line of MeV heavy ions for materials modification and in-situ analysis

International Nuclear Information System (INIS)

Horino, Yuji; Chayahara, Akiyoshi; Kiuchi, Masato; Fujii, Kanenaga; Satoh, Mamoru; Takai, Mikio.

1990-01-01

A microbeam line for MeV heavy ions of almost any element has been developed for microion-beam processing such as maskless MeV ion implantation and its in-situ analysis. Beam spot sizes of 4.0 μm x 4.0 μm for 3 MeV C 2+ and 9.6 μm x 4.8 μm for 1.8 MeV Au 2+ beams were obtained. Maskless MeV gold ion implantation to a silicon substrate and in-situ microanalysis before and after ion implantation were demonstrated. (author)

In-situ observation of damage evolution in TiC crystals during helium ion irradiation

International Nuclear Information System (INIS)

Hojou, K.; Otsu, H.; Furuno, S.; Izui, K.; Tsukamoto, T.

1994-01-01

In-situ observations were performed on bubble formation and growth in TiC during 20 keV helium ion irradiation over the wide range of irradiation temperatures from 12 to 1523 K. No amorphization occurred over this temperature range. The bubble densities and sizes were almost independent of irradiation temperatures from 12 to 1273 K. Remarkable growth and coalescence occurred during irradiation at high temperature above 1423 K and during annealing above 1373 K after irradiation. ((orig.))

Accessing the application of in situ cosmogenic 14C to surface exposure dating of amorphous SiO2

Science.gov (United States)

Cesta, J. M.; Goehring, B. M.; Ward, D. J.

2017-12-01

We assess the feasibility and utility of in situ cosmogenic 14C as a geochronometer for landforms composed of amorphous SiO2 through the comparison of 14C surface exposure ages to independently determined eruption ages on Obsidian Dome, California. Landforms composed of amorphous SiO2 phases are difficult to date by conventional cosmogenic nuclide methods due to several complications that may arise (e.g., inability to remove meteoric contamination). The onset of an increased understanding of production rates and analytical measurement of in situ 14C in SiO2 provides an opportunity to address this limitation. Obsidian Dome is a 600-year-old phreatomagmatic dome of the Mono-Inyo Craters located in Inyo County, California, and consists of vesicular pumice, obsidian, and rhyolite. Exposure ages from eight obsidian and banded pumice and obsidian surface samples range from 3947 ± 678 to 914 ± 134 years, all significantly older than the accepted radiocarbon age of 650-550 years. δ13C values for the samples range between +2.65‰ and +1.34‰ and show a negative correlation with CO2 yield. The `too old' exposure ages coupled with this negative correlation between δ13C and CO2 yield suggests the incorporation of an atmospheric component of 14C. Measurement of 14C concentrations in shielded, subsurface samples will assist in isolating the atmospheric 14C component and aid in correcting the surface exposure ages.

Plant-mediated CH4 transport and C gas dynamics quantified in-situ in a Phalaris arundinacea-dominant wetland

DEFF Research Database (Denmark)

Jensen, Louise Askær; Elberling, Bo; Friborg, Thomas

2011-01-01

passive. Thus, diurnal variations are less important in contrast to wetland vascular plants facilitating convective gas flow. Despite of plant-dominant CH4 transport, net CH4 fluxes were low (–0.005–0.016 µmol m-2 s-1) and annually less than 1% of the annual C-CO2 assimilation. This is considered a result......±35% of ecosystem CH4 emissions were plant-mediated, but data show no evidence of significant diurnal variations related to convective gas flow regardless of season or plant growth stages. Therefore, despite a high percentage of arenchyma, P. arundinacea-mediated CH4 transport is interpreted to be predominantly...

Microstructure and mechanical properties of TiC/Al(7075) composites fabricated by in situ reaction%原位合成TiC/Al(7075)复合材料的组织及力学性能

Institute of Scientific and Technical Information of China (English)

吴瑞瑞; 李秋书; 郭璐; 马雁翔; 王荣峰

2017-01-01

TiC/Al(7075) composites were fabricated by in situ reaction.The influence of in situ TiC particles form,distribution state and content on the microstructure and mechanical properties of the TiC/Al(7075) compo-sites were discussed.The results show that most spherical in situ TiC particles with aggregate exists in 7075 matrix,the cluster of grain size is about 1 μm.When the mass fraction of in situ TiC particles is less than 6%,the TiC distribution is more uniform.With the increase of in situ TiC particles,the grain sizes of the TiC/Al(7075) composites decrease significantly.But the porosity appear in the microstrcuture when the mass fraction of in situ TiC particles is more than 6%.Hardness and toughness of composite material testing shows that with the increase of the TiC particle concentration,the highest hardness of the surface reaches HB 108,the composites with 6% TiC have the best toughness,the toughness increases by 31.55% compared with the 7075 matrix.%采用原位合成法制备TiC/Al(7075)复合材料,研究原位TiC颗粒的存在形式、分布状态及不同原位TiC颗粒含量对TiC/Al(7075)复合材料的微观组织及力学性能的影响.结果显示,TiC颗粒多以近球形团聚态存在于7075铝基体中,颗粒团大小约为1 μm.当原位TiC颗粒质量分数小于6%时,原位TiC颗粒分布较为均匀,随着颗粒含量的增加,TiC/Al(7075)复合材料的铸态组织由蔷薇状组织逐渐转变为等轴晶组织,晶粒尺寸也随着原位TiC颗粒含量的增加而减小.当原位TiC颗粒的质量分数大于6%时,组织中出现气孔.复合材料的硬度和抗冲击韧性测试表明,TiC/Al(7075)复合材料的硬度随TiC颗粒含量的增加而增加,最高硬度达HB 108,冲击韧性在颗粒质量分数为6%时达到最佳,较基体提升31.55%.

A porous C/LiFePO4/multiwalled carbon nanotubes cathode material for Lithium ion batteries

International Nuclear Information System (INIS)

Qin, Guohui; Ma, Qianqian; Wang, Chengyang

2014-01-01

Highlights: •C/LiFePO 4 /MWCNT was synthesized by a incorporation of sol-gel approach and an electro-polymerization progress with a subsequent carbonization progress. •The prepared C/LiFePO 4 /MWCNTs electrode presents high-rate ability, cyclic stability, and a relative volume density. •Such cathode material is an alternative candidate for high power lithium ion batteries. -- Abstract: Three dimensional (3D) porous C/LiFePO 4 /MWCNTs was synthesized by a hybrid of in situ sol gel strategy and a facile electro-polymerization polyaniline technique and a simultaneous sintering progress. In combined with the 3D hierarchical pore topologies and high electronic conduction facilitating the kinetics of both electron transport and lithium ion diffusion within the particles, the optimized electrodes exhibit an ultrahigh rate capacity, stable charge/discharge cycle ability, and a comparative volume capacity. The synthesized LiFePO 4 composite offers a discharge capacity of 169.6mAhg −1 (nearly to its the theoretical capability 170mAhg −1 ) at the C/10 rate and delivers a good rate performance with a capacity of 141.9mAh g −1 at a high rate of 20 C, and stable charge/discharge cycle ability (>95% capacity retention after 200 charge/discharge cycles).This non-organic facile synthesize avenue can be high desirable to prepare high-power electrode materials

Complete genomic sequences for hepatitis C virus subtypes 4b, 4c, 4d, 4g, 4k, 4l, 4m, 4n, 4o, 4p, 4q, 4r and 4t.

Science.gov (United States)

Li, Chunhua; Lu, Ling; Wu, Xianghong; Wang, Chuanxi; Bennett, Phil; Lu, Teng; Murphy, Donald

2009-08-01

In this study, we characterized the full-length genomic sequences of 13 distinct hepatitis C virus (HCV) genotype 4 isolates/subtypes: QC264/4b, QC381/4c, QC382/4d, QC193/4g, QC383/4k, QC274/4l, QC249/4m, QC97/4n, QC93/4o, QC139/4p, QC262/4q, QC384/4r and QC155/4t. These were amplified, using RT-PCR, from the sera of patients now residing in Canada, 11 of which were African immigrants. The resulting genomes varied between 9421 and 9475 nt in length and each contains a single ORF of 9018-9069 nt. The sequences showed nucleotide similarities of 77.3-84.3 % in comparison with subtypes 4a (GenBank accession no. Y11604) and 4f (EF589160) and 70.6-72.8 % in comparison with genotype 1 (M62321/1a, M58335/1b, D14853/1c, and 1?/AJ851228) reference sequences. These similarities were often higher than those currently defined by HCV classification criteria for subtype (75.0-80.0 %) and genotype (67.0-70.0 %) division, respectively. Further analyses of the complete and partial E1 and partial NS5B sequences confirmed these 13 'provisionally assigned subtypes'.

Identification and functional verification of archaeal-type phosphoenolpyruvate carboxylase, a missing link in archaeal central carbohydrate metabolism.

Science.gov (United States)

Ettema, Thijs J G; Makarova, Kira S; Jellema, Gera L; Gierman, Hinco J; Koonin, Eugene V; Huynen, Martijn A; de Vos, Willem M; van der Oost, John

2004-11-01

Despite the fact that phosphoenolpyruvate carboxylase (PEPC) activity has been measured and in some cases even purified from some Archaea, the gene responsible for this activity has not been elucidated. Using sensitive sequence comparison methods, we detected a highly conserved, uncharacterized archaeal gene family that is distantly related to the catalytic core of the canonical PEPC. To verify the predicted function of this archaeal gene family, we cloned a representative from the hyperthermophilic acidophile Sulfolobus solfataricus and functionally produced the corresponding enzyme as a fusion with the Escherichia coli maltose-binding protein. The purified fusion protein indeed displayed highly thermostable PEPC activity. The structural and biochemical properties of the characterized archaeal-type PEPC (atPEPC) from S. solfataricus are in good agreement with previously reported biochemical analyses of other archaeal PEPC enzymes. The newly identified atPEPC, with its distinct properties, constitutes yet another example of the versatility of the enzymes of the central carbon metabolic pathways in the archaeal domain.

Low-temperature growth of polycrystalline Ge thin film on glass by in situ deposition and ex situ solid-phase crystallization for photovoltaic applications

International Nuclear Information System (INIS)

Tsao, Chao-Yang; Weber, Juergen W.; Campbell, Patrick; Widenborg, Per I.; Song, Dengyuan; Green, Martin A.

2009-01-01

Poly-crystalline germanium (poly-Ge) thin films have potential for lowering the manufacturing cost of photovoltaic devices especially in tandem solar cells, but high crystalline quality would be required. This work investigates the crystallinity of sputtered Ge thin films on glass prepared by in situ growth and ex situ solid-phase crystallization (SPC). Structural properties of the films were characterized by Raman, X-ray diffraction and ultraviolet-visible reflectance measurements. The results show the transition temperature from amorphous to polycrystalline is between 255 deg. C and 280 deg. C for in situ grown poly-Ge films, whereas the transition temperature is between 400 deg. C and 500 deg. C for films produced by SPC for a 20 h annealing time. The in situ growth in situ crystallized poly-Ge films at 450 deg. C exhibit significantly better crystalline quality than those formed by solid-phase crystallization at 600 deg. C. High crystalline quality at low substrate temperature obtained in this work suggests the poly-Ge films could be promising for use in thin film solar cells on glass.

In situ X-ray diffraction characterisation of Fe0.5TiOPO4 and Cu0.5TiOPO4 as electrode material for sodium-ion batteries

International Nuclear Information System (INIS)

Bleith, Peter; Kaiser, Hermann; Novák, Petr; Villevieille, Claire

2015-01-01

Na-ion batteries might become a low-cost alternative to Li-ion batteries in the future. Suitable electrode materials, especially anode materials, are needed for Na-ion batteries. As possible candidates Cu 0.5 TiOPO 4 and Fe 0.5 TiOPO 4 were tested. While Cu 0.5 TiOPO 4 does not react with Na + , Fe 0.5 TiOPO 4 shows a specific charge of ≈600 mAh/g upon the first sodiation and 280 mAh/g in the first desodiation. In situ XRD in a new, versatile and reliable in situ cell revealed that Fe 0.5 TiOPO 4 reacts via a conversion type reaction upon sodiation with an amorphisation of the sample

Hot pressing of B{sub 4}C/SiC composites

Energy Technology Data Exchange (ETDEWEB)

Sahin, F.C.; Turhan, E.; Yesilcubuk, S.A.; Addemir, O. [Ystanbul Technical University, Faculty of Chemistry and Metallurgy, Materials and Metallurgical Engineering Dept., Maslak-Ystanbul (Turkey)

2005-07-01

B{sub 4}C/SiC ceramic composites containing 10-20-30 vol % SiC were prepared by hot pressing method. The effect of SiC addition and hot pressing temperature on sintering behaviour and mechanical properties of hot pressed composites were investigated. Microstructures of hot pressed samples were examined by SEM technique. Three different temperatures (2100 deg. C, 2200 deg. C and 2250 deg. C) were used to optimize hot pressing temperature applying 100 MPa pressure under argon atmosphere during the sintering procedure. The highest relative density of 98.44 % was obtained by hot pressing at 2250 deg. C. However, bending strengths of B{sub 4}C/SiC composite samples were lower than monolithic B{sub 4}C in all experimental conditions. (authors)

Effect of TiC content on the microstructure and properties of Ti3SiC2-TiC composites in situ fabricated by spark plasma sintering

International Nuclear Information System (INIS)

Zhang Jianfeng; Wang Lianjun; Jiang Wan; Chen Lidong

2008-01-01

Spark plasma sintering technique was used to in situ fabricate high dense Ti 3 SiC 2 -TiC composites. The calculated TiC volume content from X-ray diffraction (XRD) is close to the theoretical one. It is found from fracture surface observation that TiC is about 1 μm, and Ti 3 SiC 2 is about 2-10 μm in grain size. The fracture modes consist of intergranular mainly for Ti 3 SiC 2 and transgranular fracture mainly for TiC. With the increasing of TiC volume content, Vickers hardness increases to the maximum value of 13 GPa for Ti 3 SiC 2 -40 vol.%TiC. Fracture toughness and flexural strength of the composites are also improved compared with those of monolithic Ti 3 SiC 2 except for Ti 3 SiC 2 -40 vol.%TiC composite. The main reasons for the sudden decrease of fracture toughness and flexural strength of Ti 3 SiC 2 -40 vol.%TiC composite can be attributed to the relatively lower density, some clusters of TiC in the composite and the transition of fracture mode from intergranular to transgranular. The thermal conductivities decreased with the addition of TiC. The minimum thermal conductivity is 22 W m deg. C -1 for Ti 3 SiC 2 -40 vol.%TiC composite

In-situ neutron diffraction study of Zircaloy 4 subjected to biaxial tension

Energy Technology Data Exchange (ETDEWEB)

Gharghouri, M.A. [Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, ON (Canada); McDonald, D.; Xiao, L. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

2014-07-01

Zircaloy-4 is widely used as fuel element cladding in nuclear reactors. Pellet-clad interaction (PCI) failure is a concern for many water reactor fuel designs. Extensive work on the mechanism of PCI failure has led to the conclusion that stress corrosion cracking (SCC) induced by iodine vapour in the temperature range relevant to fuel operation is the most probable cause of PCI failure in zirconium alloy fuel element cladding. In-situ neutron diffraction measurements performed on tubular Zircaloy-4 specimens simultaneously pulled in tension and pressurized internally will provide information on the effects of stress biaxiality on the distribution of stresses at the crystal level during loading. (author)

CH4 emissions from European Major Population Centers: Results from aircraft-borne CH4 in-situ observations during EMeRGe-Europe campaign 2017

Science.gov (United States)

Roiger, A.; Klausner, T.; Schlager, H.; Ziereis, H.; Huntrieser, H.; Baumann, R.; Eirenschmalz, L.; Joeckel, P.; Mertens, M.; Fisher, R.; Bauguitte, S.; Young, S.; Andrés Hernández, M. D.

2017-12-01

Urban environments represent large and diffuse area sources of CH4 including emissions from pipeline leaks, industrial/sewage treatment plants, and landfills. However, there is little knowledge about the exact magnitude of these emissions and their contribution to total anthropogenic CH4. Especially in the context of an urbanizing world, a better understanding of the methane footprint of urban areas is crucial, both with respect to mitigation and projection of climate impacts. Aircraft-borne in-situ measurements are particularly useful to both quantify emissions from such area sources, as well as to study their impact on the regional distribution. However, airborne CH4 observations downstream of European cities are especially sparse.Here we report from aircraft-borne CH4 in-situ measurements as conducted during the HALO aircraft campaign EMeRGe (Effect of Megacities on the Transport and Transformation of Pollutants on the Regional to Global Scales) in July 2017, which was led by the University of Bremen, Germany. During seven research flights, emissions from a variety of European (Mega)-cities were probed at different altitudes from 3km down to 500m, including measurements in the outflows of London, Rome, Po Valley, Ruhr and Benelux. We will present and compare the CH4 distribution measured downstream of the various studied urban hot-spots. With the help of other trace gas measurements (including e.g. CO2, CO, O3, SO2), observed methane enhancements will be attributed to the different potential source types. Finally, by the combination of in-situ measurements and regional model simulations using the EMAC-MECO(n) model, the contribution of emissions from urban centers to the regional methane budget over Europe will be discussed.

In situ optical emission study on the role of C2 in the synthesis of singlewalled carbon nanotubes

CSIR Research Space (South Africa)

Motaung, DE

2010-01-01

Full Text Available applications. In this study, the authors have applied in situ optical emission spectroscopy (OES) to study the plasma in the laser-furnace method to synthesize SWCNTs. In particular, the authors have investigated the temporal and spatial behavior of C2 as well...

In situ detection of microbial c-type cytochrome based on intrinsic peroxidase-like activity using screen-printed carbon electrode.

Science.gov (United States)

Wen, Junlin; He, Daigui; Yu, Zhen; Zhou, Shungui

2018-08-15

C-type cytochromes (c-cyts) facilitate microbial extracellular electron transfer and play critical roles in biogeochemical cycling, bioelectricity generation and bioremediation. In this study, a simple and effective method has been developed to detect microbial c-cyts by means of peroxidase mimetic reaction on screen-printed carbon electrode (SPCE). To this end, bacteria cells were immobilized onto the working electrode surface of SPCE by a simple drop casting. After introducing 3,3',5,5'-tetramethylbenzidine (TMB) solution, microbial c-cyts with peroxidase-like activity catalyze the oxidation of TMB in the presence of hydrogen peroxide. The oxidized TMB was electrochemically determined and the current signal was employed to calculate the c-cyts content. This electrochemical method is highly sensitive for microbial c-cyts with a low detection limit of 40.78 fmol and a wide detection range between 51.70 fmol and 6.64 pmol. Moreover, the proposed technique can be universally expanded to detect c-cyts in other bacteria species such as Fontibacter ferrireducens, Pseudomonas aeruginosa, Comamonas guangdongensis and Escherichia coli. Furthermore, the proposed method confers an in situ facile and quantitative c-cyts detection without any destructive sample preparations, complex electrode modifications and expensive enzyme- or metal particle- based signal amplification. The suggested method advances an intelligent strategy for in situ quantification of microbial c-cyts and consequently holds promising application potential in microbiology and environmental science. Copyright © 2018 Elsevier B.V. All rights reserved.

Localization of pig Na[sup +], K[sup +]-ATPase [alpha] and [beta] subunit genes to chromosome 4 by radioactive in situ hybridization

Energy Technology Data Exchange (ETDEWEB)

Lahbib-Mansais, Y.; Yerle, M.; Dalens, M.; Chevalet, C.; Gellin, J. (Centre de Recherches de Toulouse (France))

1993-01-01

Two genes coding for Na[sup +],K[sup +] -ATPase [alpha] and [beta] subunits are localized on pig chromosome 4, to the q1.6[yields]q2.3 and 1.3[yields]q2.1 regions, respectively, by radioactive in situ hybridization. According to nucleotide and amino acid sequence comparisons with different human isoforms of Na[sup +] ,K[sup +]-ATPase, these pig [alpha] and [beta] ATPase genes show strong homologies with human [alpha]1 and [beta] subunit ATPase genes, respectively. These results are discussed with respect to comparative mapping data of conserved genes in mammalian species. We showed that the pig cDNA probes encoding ATPase [alpha] and, [beta] genes reveal DNA polymorphism in Meishan an Large White pigs. 35 refs., 4 figs., 2 tabs.

4C-ker: A Method to Reproducibly Identify Genome-Wide Interactions Captured by 4C-Seq Experiments.

Science.gov (United States)

Raviram, Ramya; Rocha, Pedro P; Müller, Christian L; Miraldi, Emily R; Badri, Sana; Fu, Yi; Swanzey, Emily; Proudhon, Charlotte; Snetkova, Valentina; Bonneau, Richard; Skok, Jane A

2016-03-01

4C-Seq has proven to be a powerful technique to identify genome-wide interactions with a single locus of interest (or "bait") that can be important for gene regulation. However, analysis of 4C-Seq data is complicated by the many biases inherent to the technique. An important consideration when dealing with 4C-Seq data is the differences in resolution of signal across the genome that result from differences in 3D distance separation from the bait. This leads to the highest signal in the region immediately surrounding the bait and increasingly lower signals in far-cis and trans. Another important aspect of 4C-Seq experiments is the resolution, which is greatly influenced by the choice of restriction enzyme and the frequency at which it can cut the genome. Thus, it is important that a 4C-Seq analysis method is flexible enough to analyze data generated using different enzymes and to identify interactions across the entire genome. Current methods for 4C-Seq analysis only identify interactions in regions near the bait or in regions located in far-cis and trans, but no method comprehensively analyzes 4C signals of different length scales. In addition, some methods also fail in experiments where chromatin fragments are generated using frequent cutter restriction enzymes. Here, we describe 4C-ker, a Hidden-Markov Model based pipeline that identifies regions throughout the genome that interact with the 4C bait locus. In addition, we incorporate methods for the identification of differential interactions in multiple 4C-seq datasets collected from different genotypes or experimental conditions. Adaptive window sizes are used to correct for differences in signal coverage in near-bait regions, far-cis and trans chromosomes. Using several datasets, we demonstrate that 4C-ker outperforms all existing 4C-Seq pipelines in its ability to reproducibly identify interaction domains at all genomic ranges with different resolution enzymes.

4C-ker: A Method to Reproducibly Identify Genome-Wide Interactions Captured by 4C-Seq Experiments.

Directory of Open Access Journals (Sweden)

Ramya Raviram

2016-03-01

Full Text Available 4C-Seq has proven to be a powerful technique to identify genome-wide interactions with a single locus of interest (or "bait" that can be important for gene regulation. However, analysis of 4C-Seq data is complicated by the many biases inherent to the technique. An important consideration when dealing with 4C-Seq data is the differences in resolution of signal across the genome that result from differences in 3D distance separation from the bait. This leads to the highest signal in the region immediately surrounding the bait and increasingly lower signals in far-cis and trans. Another important aspect of 4C-Seq experiments is the resolution, which is greatly influenced by the choice of restriction enzyme and the frequency at which it can cut the genome. Thus, it is important that a 4C-Seq analysis method is flexible enough to analyze data generated using different enzymes and to identify interactions across the entire genome. Current methods for 4C-Seq analysis only identify interactions in regions near the bait or in regions located in far-cis and trans, but no method comprehensively analyzes 4C signals of different length scales. In addition, some methods also fail in experiments where chromatin fragments are generated using frequent cutter restriction enzymes. Here, we describe 4C-ker, a Hidden-Markov Model based pipeline that identifies regions throughout the genome that interact with the 4C bait locus. In addition, we incorporate methods for the identification of differential interactions in multiple 4C-seq datasets collected from different genotypes or experimental conditions. Adaptive window sizes are used to correct for differences in signal coverage in near-bait regions, far-cis and trans chromosomes. Using several datasets, we demonstrate that 4C-ker outperforms all existing 4C-Seq pipelines in its ability to reproducibly identify interaction domains at all genomic ranges with different resolution enzymes.

Techno-economic and uncertainty analysis of in situ and ex situ fast pyrolysis for biofuel production

Energy Technology Data Exchange (ETDEWEB)

Li, Boyan; Ou, Longwen; Dang, Qi; Meyer, Pimphan A.; Jones, Susanne B.; Brown, Robert C.; Wright, Mark

2015-11-01

This study evaluates the techno-economic uncertainty in cost estimates for two emerging biorefinery technologies for biofuel production: in situ and ex situ catalytic pyrolysis. Stochastic simulations based on process and economic parameter distributions are applied to calculate biorefinery performance and production costs. The probability distributions for the minimum fuel-selling price (MFSP) indicate that in situ catalytic pyrolysis has an expected MFSP of $4.20 per gallon with a standard deviation of 1.15, while the ex situ catalytic pyrolysis has a similar MFSP with a smaller deviation ($4.27 per gallon and 0.79 respectively). These results suggest that a biorefinery based on ex situ catalytic pyrolysis could have a lower techno-economic risk than in situ pyrolysis despite a slightly higher MFSP cost estimate. Analysis of how each parameter affects the NPV indicates that internal rate of return, feedstock price, total project investment, electricity price, biochar yield and bio-oil yield are significant parameters which have substantial impact on the MFSP for both in situ and ex situ catalytic pyrolysis.

Band line-up determination at p- and n-type Al/4H-SiC Schottky interfaces using photoemission spectroscopy

Science.gov (United States)

Kohlscheen, J.; Emirov, Y. N.; Beerbom, M. M.; Wolan, J. T.; Saddow, S. E.; Chung, G.; MacMillan, M. F.; Schlaf, R.

2003-09-01

The band lineup of p- and n-type 4H-SiC/Al interfaces was determined using x-ray photoemission spectroscopy (XPS). Al was deposited in situ on ex situ cleaned SiC substrates in several steps starting at 1.2 Å up to 238 Å nominal film thickness. Before growth and after each growth step, the sample surface was characterized in situ by XPS. The analysis of the spectral shifts indicated that during the initial deposition stages the Al films react with the ambient surface contamination layer present on the samples after insertion into vacuum. At higher coverage metallic Al clusters are formed. The band lineups were determined from the analysis of the core level peak shifts and the positions of the valence bands maxima (VBM) depending on the Al overlayer thickness. Shifts of the Si 2p and C 1s XPS core levels occurred to higher (lower) binding energy for the p-(n-)type substrates, which was attributed to the occurrence of band bending due to Fermi-level equilibration at the interface. The hole injection barrier at the p-type interface was determined to be 1.83±0.1 eV, while the n-type interface revealed an electron injection barrier of 0.98±0.1 eV. Due to the weak features in the SiC valence bands measured by XPS, the VBM positions were determined using the Si 2p peak positions. This procedure required the determination of the Si 2p-to-VBM binding energy difference (99.34 eV), which was obtained from additional measurements.

In Situ Soft X-ray Spectromicroscopy of Early Tricalcium Silicate Hydration

Directory of Open Access Journals (Sweden)

Sungchul Bae

2016-12-01

Full Text Available The understanding and control of early hydration of tricalcium silicate (C3S is of great importance to cement science and concrete technology. However, traditional characterization methods are incapable of providing morphological and spectroscopic information about in situ hydration at the nanoscale. Using soft X-ray spectromicroscopy, we report the changes in morphology and molecular structure of C3S at an early stage of hydration. In situ C3S hydration in a wet cell, beginning with induction (~1 h and acceleration (~4 h periods of up to ~8 h, was studied and compared with ex situ measurements in the deceleration period after 15 h of curing. Analysis of the near-edge X-ray absorption fine structure showed that the Ca binding energy and energy splitting of C3S changed rapidly in the early age of hydration and exhibited values similar to calcium silicate hydrate (C–S–H. The formation of C–S–H nanoseeds in the C3S solution and the development of a fibrillar C–S–H morphology on the C3S surface were visualized. Following this, silicate polymerization accompanied by C–S–H precipitation produced chemical shifts in the peaks of the main Si K edge and in multiple scattering. However, the silicate polymerization process did not significantly affect the Ca binding energy of C–S–H.

Synthesis of 11-14C-quetiapine, 11-14C-isoclotiapine and 10-(4-methylpiperazin-1-yl)pyrido[4,3-b][1,4]benzothiazepine[10-14C

International Nuclear Information System (INIS)

Naghi Saadatjoo; Mohsen Javaheri; Nuclear Science and Technology Research Institute, Tehran; Nader Saemian; Mohsen Amini

2016-01-01

Quetiapine is one of the most widely used antipsychotic drug which acts as an antagonist for multiple neurotransmitter receptor sites. 2-[2-(4-(Dibenzo[b,f][1,4]thiazepin-11-yl)piperazin-1-yl)ethoxy]ethanol (quetiapine) labeled with carbon-14 in 11-position has been synthesized as part of a 5-step sequence from anthranilic acid-[carboxy- 14 C]. We have presented a convenient synthetic pathway for labeling of quetiapine with carbon-14 by using one-pot procedures from a key thiazepin-11(10H)-one-[11- 14 C] by good radiochemical yield. And also isoclotiapine[11- 14 C], and 10-(4-methylpiperazin-1-yl)pyrido[4,3-b][1,4]benzothiazepine[10- 14 C], synthesized according to this route. (author)

Ultrafine Nanocrystalline CeO2@C-Containing NaAlH4 with Fast Kinetics and Good Reversibility for Hydrogen Storage.

Science.gov (United States)

Zhang, Xin; Liu, Yongfeng; Wang, Ke; Li, You; Gao, Mingxia; Pan, Hongge

2015-12-21

A nanocrystalline CeO2@C-containing NaAlH4 composite is successfully synthesized in situ by hydrogenating a NaH-Al mixture doped with CeO2@C. Compared with NaAlH4 , the as-prepared CeO2@C-containing NaAlH4 composite, with a minor amount of excess Al, exhibits significantly improved hydrogen storage properties. The dehydrogenation onset temperature of the hydrogenated [NaH-Al-7 wt % CeO2@C]-0.04Al sample is 77 °C lower than that of the pristine sample because of a reduced kinetic barrier. More importantly, the dehydrogenated sample absorbs ∼4.7 wt % hydrogen within 35 min at 100°C and 10 MPa of hydrogen. Compositional and structural analyses reveal that CeO2 is converted to CeH2 during ball milling and that the newly formed CeH2 works with the excess of Al to synergistically improve the hydrogen storage properties of NaAlH4. Our findings will aid in the rational design of novel catalyst-doped complex hydride systems with low operating temperatures, fast kinetics, and long-term cyclability. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unique photosynthetic phenotypes in Portulaca (Portulacaceae): C3-C4 intermediates and NAD-ME C4 species with Pilosoid-type Kranz anatomy.

Science.gov (United States)

Voznesenskaya, Elena V; Koteyeva, Nuria K; Edwards, Gerald E; Ocampo, Gilberto

2017-01-01

Portulacaceae is a family that has considerable diversity in photosynthetic phenotypes. It is one of 19 families of terrestrial plants where species having C 4 photosynthesis have been found. Most species in Portulaca are in the alternate-leaved (AL) lineage, which includes one clade (Cryptopetala) with taxa lacking C 4 photosynthesis and three clades having C 4 species (Oleracea, Umbraticola and Pilosa). All three species in the Cryptopetala clade lack Kranz anatomy, the leaves have C 3 -like carbon isotope composition and they have low levels of C 4 cycle enzymes. Anatomical, biochemical and physiological analyses show they are all C 3 -C 4 intermediates. They have intermediate CO 2 compensation points, enrichment of organelles in the centripetal position in bundle sheath (BS) cells, with selective localization of glycine decarboxylase in BS mitochondria. In the three C 4 clades there are differences in Kranz anatomy types and form of malic enzyme (ME) reported to function in C 4 (NAD-ME versus NADP-ME): Oleracea (Atriplicoid, NAD-ME), Umbraticola (Atriplicoid, NADP-ME) and Pilosa (Pilosoid, NADP-ME). Structural and biochemical analyses were performed on Pilosa clade representatives having Pilosoid-type leaf anatomy with Kranz tissue enclosing individual peripheral vascular bundles and water storage in the center of the leaf. In this clade, all species except P. elatior are NADP-ME-type C 4 species with grana-deficient BS chloroplasts and grana-enriched M chloroplasts. Surprisingly, P. elatior has BS chloroplasts enriched in grana and NAD-ME-type photosynthesis. The results suggest photosynthetic phenotypes were probably derived from an ancestor with NADP-ME-type C 4 , with two independent switches to NAD-ME type. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

In-situ growing NiCo2O4 nanoplatelets on carbon cloth as binder-free catalyst air-cathode for high-performance microbial fuel cells

International Nuclear Information System (INIS)

Cao, Chun; Wei, Liling; Wang, Gang; Shen, Jianquan

2017-01-01

Highlights: • NiCo 2 O 4 nanoplatelets were in-situ growing on carbon cloth as ORR catalyst in biofuel cells. • Binder-free cathode with the lower internal resistance. • Binder-free cathode was low-cost. • NiCo 2 O 4 -CFC shows better power generation performance than Pt/C. - Abstract: Air-cathode microbial fuel cells (MFCs) was one of most promising sustainable new energy device as well as an advanced sewage treatment technology, and thoroughly studies have been devoted to lower its cost and enhance its power generation. Herein, a binder-free and low-cost catalyst air-cathode was fabricated by in-situ electro-deposition of NiCo 2 O 4 nanoplatelets on carbon cloth, followed by feasible calcinations. The catalytic activity of catalyst air-cathode was optimized by varying the deposition time. And the optimal air-cathode was installed in real MFCs and exhibited distinct maximum out-put power density (645 ± 6 mW m −2 ), which was 12.96% higher than commercial Pt/C (571 ± 11 mW m −2 ). Noted that its remarkable electricity generation performance in MFCs should absolutely attributed to the well catalytic activity for oxygen reduction reaction, and more likely ascribed to its low internal resistance since binder-free catalyst air-cathode can facilitate the electron/charge transfer process. Therefore, it was an efficient strategy to improve the electricity generation performance of MFCs by using this binder-free catalyst air-cathode, which was also potential for application in many other electrochemical devices.

Surface polymerization of (3,4-ethylenedioxythiophene) probed by in situ scanning tunneling microscopy on Au(111) in ionic liquids.

Science.gov (United States)

Ahmad, Shahzada; Carstens, Timo; Berger, Rüdiger; Butt, Hans-Jürgen; Endres, Frank

2011-01-01

The electropolymerization of 3,4-ethylenedioxythiophene (EDOT) to poly(3,4-ethylenedioxythiophene) (PEDOT) was investigated in the air and water-stable ionic liquids 1-hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate [HMIm]FAP and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide [EMIm]TFSA. In situ scanning tunnelling microscopy (STM) results show that the electropolymerization of EDOT in the ionic liquid can be probed on the nanoscale. In contrast to present understanding, it was observed that the EDOT can be oxidised in ionic liquids well below its oxidation potential and the under potential growth of polymer was visualized by in situ STM. These results serve as the first study to confirm the under potential growth of conducting polymers in ionic liquids. Furthermore, ex situ microscopy measurements were performed. Quite a high current of 670 nA was observed on the nanoscale by conductive scanning force microscopy (CSFM).

In-situ XRD study of alloyed Cu2ZnSnSe4-CuInSe2 thin films for solar cells

International Nuclear Information System (INIS)

Hartnauer, Stefan; Wägele, Leonard A.; Jarzembowski, Enrico; Scheer, Roland

2015-01-01

We investigate the growth of Cu 2 ZnSnSe 4 -CuInSe 2 (CZTISe) thin films using a 2-stage (Cu-rich/Cu-free) co-evaporation process under simultaneous application of in-situ angle dispersive X-ray diffraction (XRD). In-situ XRD allows monitoring the phase formation during preparation. A variation of the content of indium in CZTISe leads to a change in the lattice constant. Single phase CZTISe is formed in a wide range, while at high In contents a phase separation is detected. Because of different thermal expansion coefficients, the X-ray diffraction peaks of ZnSe and CZTISe can be distinguished at elevated substrate temperatures. The formation of ZnSe appears to be inhibited even for low indium content. In-situ XRD shows no detectable sign for the formation of ZnSe. First solar cells of CZTISe have been prepared and show comparable performance to CZTSe. - Highlights: • In-situ XRD study of two-stage co-evaporated Cu 2 ZnSnSe 4 -CuInSe 2 alloyed thin films. • No detection of ZnSe with in-situ XRD due to Indium incorporation • Comparable efficiency of alloyed solar cells

Revealing diversity in structural and biochemical forms of C4 photosynthesis and a C3-C4 intermediate in genus Portulaca L. (Portulacaceae).

Science.gov (United States)

Voznesenskaya, Elena V; Koteyeva, Nuria K; Edwards, Gerald E; Ocampo, Gilberto

2010-08-01

Portulacaceae is one of 19 families of terrestrial plants in which species having C(4) photosynthesis have been found. Representative species from major clades of the genus Portulaca were studied to characterize the forms of photosynthesis structurally and biochemically. The species P. amilis, P. grandiflora, P. molokiniensis, P. oleracea, P. pilosa, and P. umbraticola belong to the subgenus Portulaca and are C(4) plants based on leaf carbon isotope values, Kranz anatomy, and expression of key C(4) enzymes. Portulaca umbraticola, clade Umbraticola, is NADP-malic enzyme (NADP-ME)-type C(4) species, while P. oleracea and P. molokiniensis in clade Oleracea are NAD-ME-type C(4) species, all having different forms of Atriplicoid-type leaf anatomy. In clade Pilosa, P. amilis, P. grandiflora, and P. pilosa are NADP-ME-type C(4) species. They have Pilosoid-type anatomy in which Kranz tissues enclose peripheral vascular bundles with water storage in the centre of the leaf. Portulaca cf. bicolor, which belongs to subgenus Portulacella, is an NADP-ME C(4) species with Portulacelloid-type anatomy; it has well-developed Kranz chlorenchyma surrounding lateral veins distributed in one plane under the adaxial epidermis with water storage cells underneath. Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C(3)-C(4) based on its intermediate CO(2) compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells. The C(4) Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C(3)-type photosynthetic cells. The results indicate that multiple structural and biochemical forms of C(4) photosynthesis evolved in genus Portulaca.

In situ Raman spectroscopy of LiFePO4: size and morphology dependence during charge and self-discharge.

Science.gov (United States)

Wu, Jing; Dathar, Gopi Krishna Phani; Sun, Chunwen; Theivanayagam, Murali G; Applestone, Danielle; Dylla, Anthony G; Manthiram, Arumugam; Henkelman, Graeme; Goodenough, John B; Stevenson, Keith J

2013-10-25

Previous studies of the size dependent properties of LiFePO4 have focused on the diffusion rate or phase transformation pathways by bulk analysis techniques such as x-ray diffraction (XRD), neutron diffraction and electrochemistry. In this work, in situ Raman spectroscopy was used to study the surface phase change during charge and self-discharge on a more localized scale for three morphologies of LiFePO4: (1) 25 ± 6 nm width nanorods, (2) 225 ± 6 nm width nanorods and (3) ∼2 μm porous microspheres. Both the large nanorod and microsphere geometries showed incomplete delithiation at the end of charge, which was most likely caused by anti-site defects along the 1D diffusion channels in the bulk of the larger particles. Based on the in situ Raman measurements, all of the morphologies studied exhibited self-discharge with time. Among them, the smallest FePO4 particles self-discharged (lithiated) the fastest. While nanostructuring LiFePO4 can offer advantages in terms of lowering anti-site defects within particles, it also creates new problems due to high surface energies that allow self-discharge. The in situ Raman spectroscopy also showed that carbon coating did not provide significant improvement to the stability of the lithiated particles.

Experimental investigation on thermochemical sulfate reduction in the presence of 1-pentanethiol at 200 and 250 °C: Implications for in situ TSR processes occurring in some MVT deposits

Science.gov (United States)

Yuan, Shunda; Ellis, Geoffrey S.; Chou, I-Ming; Burruss, Robert

2017-01-01

Organic sulfur compounds are ubiquitous in natural oil and gas fields and moderate-low temperature sulfide ore deposits. Previous studies have shown that organic sulfur compounds are important in enhancing the rates of thermochemical sulfate reduction (TSR) reactions, but the details of these reaction mechanisms remain unclear. In order to assess the extent of sulfate reduction in the presence of labile sulfur species at temperature conditions near to those where TSR occurs in nature, we conducted a series of experiments using the fused silica capillary capsule (FCSS) method. The tested systems containing labile sulfur species are MgSO4 + 1-pentanethiol (C5H11SH) + 1-octene (C8H16), MgSO4 + 1-octene (C8H16), MgSO4 + 1-pentanethiol (C5H11SH), 1-pentanethiol (C5H11SH)+H2O, and MgSO4 + 1-pentanethiol (C5H11SH) + ZnBr2 systems. Our results show that: (1) intermediate oxidized carbon species (ethanol and acetic acid) are formed during TSR simulation experiments when 1-pentanethiol is present; (2) in the presence of ZnBr2, 1-pentanethiol can be oxidized by sulfate to CO2 at 200 °C, which is within the temperature range observed in natural TSR; and (3) the precipitation of sulfide minerals may significantly promote the rate of TSR, indicating that the rates of in situ TSR reactions in ore deposits could be much faster than previously thought. This may be important for understanding the possibility of in situ TSR as a mechanism for the precipitation of metal sulfides in some ore deposits. These findings provide important experimental evidence for understanding the role of organic sulfur compounds in TSR reactions and the pathway of TSR reactions initiated by organic sulfur compounds under natural conditions.

Microstructure and mechanical properties investigation of in situ TiB2 and ZrB2 reinforced Al-4Cu composites

Science.gov (United States)

Lutfi Anis, Ahmad; Ramli, Rosmamuhammadani; Darham, Widyani; Zakaria, Azlan; Talari, Mahesh Kumar

2016-02-01

Conventional Al-Cu alloys exhibit coarse grain structure leading to inferior mechanical properties in as-cast condition. Expensive thermo-mechanical treatments are needed to improve microstructure and corresponding mechanical properties. In situ Al-based composites were developed to improve mechanical properties by dispersion strengthening and grain refinement obtained by the presence of particulates in the melt during solidification. In this work Al-4Cu - 3TiB2 and Al-4Cu-3ZrB2 in situ composites were prepared by liquid casting method. XRD, electron microscopy and mechanical tests were performed on suitably sectioned and metallographically prepared surfaces to investigate the phase distribution, hardness and tensile properties. It was found that the reinforcement particles were segregated along the grain boundaries of Al dendrites. Tensile fracture morphology for both Al-4Cu - 3TiB2 and Al-4Cu-3ZrB2 were analyzed and compared to determine the fracture propagation mechanism in the composites. Al-4Cu-3ZrB2 in situ composites displayed higher strength and hardness compared to Al-4Cu-3TiB2 which could be ascribed to the stronger interfacial bonding between the Al dendrites and ZrB2 particulates as evidenced from fractographs.

In situ remediation-released zero-valent iron nanoparticles impair soil ecosystems health: A C. elegans biomarker-based risk assessment

Energy Technology Data Exchange (ETDEWEB)

Yang, Ying-Fei; Cheng, Yi-Hsien; Liao, Chung-Min, E-mail: cmliao@ntu.edu.tw

2016-11-05

Highlights: • Fe{sup 0} NPs induced infertility risk in C. elegans. • A C.elegans-based probabilistic risk assessment model is developed. • In situ remediation-released Fe{sup 0} NPs impair soil ecosystems health. - Abstract: There is considerable concern over the potential ecotoxicity to soil ecosystems posed by zero-valent iron nanoparticles (Fe{sup 0} NPs) released from in situ environmental remediation. However, a lack of quantitative risk assessment has hampered the development of appropriate testing methods used in environmental applications. Here we present a novel, empirical approach to assess Fe{sup 0} NPs-associated soil ecosystems health risk using the nematode Caenorhabditis elegans as a model organism. A Hill-based dose-response model describing the concentration–fertility inhibition relationships was constructed. A Weibull model was used to estimate thresholds as a guideline to protect C. elegans from infertility when exposed to waterborne or foodborne Fe{sup 0} NPs. Finally, the risk metrics, exceedance risk (ER) and risk quotient (RQ) of Fe{sup 0} NPs in various depths and distances from remediation sites can then be predicted. We showed that under 50% risk probability (ER = 0.5), upper soil layer had the highest infertility risk (95% confidence interval: 13.18–57.40%). The margins of safety and acceptable criteria for soil ecosystems health for using Fe{sup 0} NPs in field scale applications were also recommended. Results showed that RQs are larger than 1 in all soil layers when setting a stricter threshold of ∼1.02 mg L{sup −1} of Fe{sup 0} NPs. This C. elegans biomarker-based risk model affords new insights into the links between widespread use of Fe{sup 0} NPs and environmental risk assessment and offers potential environmental implications of metal-based NPs for in situ remediation.

Electrochemical cell for in situ x-ray diffraction under ultrapure conditions

DEFF Research Database (Denmark)

Koop, T.; Schindler, W.; Kazimirov, A.

1998-01-01

within a few seconds. The oxygen level in the electrolyte is reduced by continuous N(2) flow to less than 0.2% compared to that of a fresh electrolyte. This can be done while rotating the cell by 360 degrees about the surface normal. The electrode potential is accurately measured at the position......An electrochemical cell has been developed for in situ x-ray diffraction from a working electrode under clean conditions equivalent to ultrahigh vacuum conditions of 5 x 10(-10) mbar. The substrate crystals can be prepared ex situ and transferred into the cell under protection of ultrapure water...... of the crystal using a Luggin capillary and a standard reference electrode. We demonstrate the performance of our cell by in situ synchrotron x-ray diffraction measurements on ultrathin Co layers electrodeposited on Cu(001) in an aqueous H(2)SO(4)/CoSO(4) solution. (C) 1998 American Institute of Physics....

Micro/nanoscale mechanical characterization and in situ observation of cracking of laminated Si3N4/BN composites

International Nuclear Information System (INIS)

Li Xiaodong; Zou Linhua; Ni Hai; Reynolds, Anthony P.; Wang Changan; Huang Yong

2008-01-01

Micro/nanoscale mechanical characterization of laminated Si 3 N 4 /BN composites was carried out by nanoindentation techniques. A custom-designed micro mechanical tester was integrated with an optical microscope and an atomic force microscope to perform in situ three-point bending tests on notched Si 3 N 4 /BN composite bend specimens where the crack initiation and propagation were imaged simultaneously with the optical microscope and atomic force microscope during bending loading. The whole fracture process was in situ captured. It was found that crack deflection was initiated/induced by the pre-existing microvoids and microcracks in BN interfacial layers. New fracture mechanisms were proposed to provide guidelines for the design of biomimetic nacre-like composites

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.

The microwave heating mechanism of N-(4-methoxybenzyliden)-4-butylaniline in liquid crystalline and isotropic phases as determined using in situ microwave irradiation NMR spectroscopy.

Science.gov (United States)

Tasei, Yugo; Tanigawa, Fumikazu; Kawamura, Izuru; Fujito, Teruaki; Sato, Motoyasu; Naito, Akira

2015-04-14

Microwave heating effects are widely used in the acceleration of organic, polymerization and enzymatic reactions. These effects are primarily caused by the local heating induced by microwave irradiation. However, the detailed molecular mechanisms associated with microwave heating effects on the chemical reactions are not yet well understood. This study investigated the microwave heating effect of N-(4-methoxybenzylidene)-4-butylaniline (MBBA) in liquid crystalline and isotropic phases using in situ microwave irradiation nuclear magnetic resonance (NMR) spectroscopy, by obtaining (1)H NMR spectra of MBBA under microwave irradiation. When heated simply using the temperature control unit of the NMR instrument, the liquid crystalline MBBA was converted to the isotropic phase exactly at its phase transition temperature (Tc) of 41 °C. The application of microwave irradiation at 130 W for 90 s while maintaining the instrument temperature at 20 °C generated a small amount of isotropic phase within the bulk liquid crystal. The sample temperature of the liquid crystalline state obtained during microwave irradiation was estimated to be 35 °C by assessing the linewidths of the (1)H NMR spectrum. This partial transition to the isotropic phase can be attributed to a non-equilibrium local heating state induced by the microwave irradiation. The application of microwave at 195 W for 5 min to isotropic MBBA while maintaining an instrument temperature of 50 °C raised the sample temperature to 160 °C. In this study, the MBBA temperature during microwave irradiation was estimated by measuring the temperature dependent chemical shifts of individual protons in the sample, and the different protons were found to indicate significantly different temperatures in the molecule. These results suggest that microwave heating polarizes bonds in polar functional groups, and this effect may partly explain the attendant acceleration of organic reactions.

SELECTIVE C-2 AND C-4 DEACYLATION AND ACYLATION OF TAXOL - THE FIRST SYNTHESIS OF A C-4 SUBSTITUTED TAXOL ANALOG

DEFF Research Database (Denmark)

GEORG, GI; ALI, SM; BOGE, TC

1994-01-01

Hydrolytic procedures for selective 2-debenzoylation and 2,4-dideacylation of 2'-0-tert-butyldimethylsilyl-7-0-(triethylsilyl)taxol are reported. The first synthesis and biological evaluation of a 4-substituted analogue, 4-deacetyl-4-isobutanoyltaxol, is presented. The chemistry described in this...... in this letter is suitable for the facile synthesis of taxol congeners modified at C-2 and/or C-4....

4,4'-Dichlorodiphenyltrichloroethane (DDT) and 4,4'-dichlorodiphenyldichloroethylene (DDE) inhibit myogenesis in C2C12 myoblasts.

Science.gov (United States)

Kim, Jonggun; Park, Min Young; Kim, Yoo; Yoon, Kyong Sup; Clark, John Marshall; Park, Yeonhwa; Whang, Kwang-Youn

2017-12-01

Most countries have banned the use of 4,4'-dichlorodiphenyltrichloroethane (DDT). However, owing to its extremely high lipophilic characteristics, DDT and its metabolite 4,4'-dichlorodiphenyldichloroethylene (DDE) are ubiquitous in the environment and in many types of food. The positive correlation between exposure to insecticides, including DDT and DDE, and weight gain, resulting in impaired energy metabolism in offspring following perinatal DDT and DDE exposure, was previously reported. Therefore the influence of DDT and DDE on myogenesis using C2C12 myoblasts was investigated in this study. DDT and DDE decreased myotube formation dose- and time-dependently. Among myogenic regulatory factors, DDT and DDE mainly decreased MyoD1 and Myf5 expression. DDT and DDE treatment also altered Myostatin expression, phosphorylation of protein kinase B, p70 ribosomal protein S6 kinase, forkhead box O protein 3 and mammalian target of rapamycin, resulting in attenuation of myotube formation. These results may have significant implications for understanding the effects of developmental exposure of DDT and DDE on myogenesis and development of obesity and type 2 diabetes later in life. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Complexing Agents on Carbon Content and Lithium Storage Capacity of LiFePO4/C Cathode Synthesized via Sol-Gel Approach

Directory of Open Access Journals (Sweden)

C. Guan

2016-01-01

Full Text Available Olivine-structured LiFePO4 faces its intrinsic challenges in terms of poor electrical conductivity and lithium-ion diffusion capability for application to lithium-ion batteries. Cost-effective sol-gel approach is advantageous to in situ synthesize carbon-coated LiFePO4 (LiFePO4/C which can not only improve electronic conductivity but also constrain particle size to nanometer scale. In this study, the key parameter is focused on the choice and amount of chelating agents in this synthesis route. It was found that stability of complexing compounds has significant impacts on the carbon contents and electrochemical properties of the products. At the favorable choice of precursors, composition, and synthesis conditions, nanocrystalline LiFePO4/C materials with appropriate amount of carbon coating were successfully obtained. A reversible capacity of 162 mAh/g was achieved at 0.2C rate, in addition to good discharge rate capability.

Effects of Ti and TiC ceramic powder on laser-cladded Ti-6Al-4V in situ intermetallic composite

Science.gov (United States)

Ochonogor, O. F.; Meacock, C.; Abdulwahab, M.; Pityana, S.; Popoola, A. P. I.

2012-12-01

Titanium metal matrix composite (MMCs) was developed on titanium alloy (Ti-6Al-4V) substrate with the aim of improving the hardness and wear properties by laser cladding technique using a Rofin Sinar 4 kW Nd: YAG laser. Wear investigations were carried out with the aid of three body abrasion tester. The resultant microstructure show homogeneous distribution of TiC particles free from cracks and pores. Multiple track deposited systems with 50% overlap revealed micro-hardness increase from 357.3 HV0.1for the substrate reaching a peak as high as 922.2 HV0.1 for 60%Ti + 40%TiC and the least 665.3 HV0.1 for 80%Ti + 20%TiC MMCs. The wear resistance of the materials improved significantly, indicating a fifteen-fold wear rate reduction due to the proper distribution of ceramic particles thereby forming interstitial carbides as revealed by the X-ray diffraction spectrum.

Emulsion drying synthesis of olivine LiFePO4/C composite and its electrochemical properties as lithium intercalation material

International Nuclear Information System (INIS)

Myung, Seung-Taek; Komaba, Shinichi; Hirosaki, Norimitsu; Yashiro, Hitoshi; Kumagai, Naoaki

2004-01-01

The electroactive LiFePO 4 /C nano-composite has been synthesized by an emulsion drying method. During burning-out the oily emulsion precipitates in an air-limited atmosphere at 300 deg. C, amorphous or low crystalline carbon was generated along with releasing carbon oxide gases, and trivalent iron as a cheap starting material was immediately reduced to the divalent one at this stage as confirmed by X-ray photoelectron spectroscopy, leading to a low crystalline LiFePO 4 /C composite. Heat-treatment of the low crystalline LiFePO 4 /C in an Ar atmosphere resulted in a well-ordered olivine structure, as refined by Rietveld refinement of the X-ray diffraction pattern. From secondary electron microscopic and scanning transmission electron microscopic observations with the corresponding elemental mapping images of iron and phosphorous, it was found that the LiFePO 4 powders are modified by fine carbon. The in situ formation of the nano-sized carbon during crystallization of LiFePO 4 brought about two advantages: (i) an optimized particle size of LiFePO 4 , and (ii) a uniform distribution of fine carbon in the product. These effects of the fine carbon on LiFePO 4 /C composite led to high capacity retention upon cycling at 25 and 50 deg. C and high rate capability, resulting from a great enhancement of electric conductivity as high as 10 -4 S cm -1 . That is, the obtained capacity was higher than 90 mAh (g-phosphate) -1 by applying a higher current density of about 1000 mA g -1 (11 C) at 50 deg. C

InterProScan Result: FS880233 [KAIKOcDNA[Archive

Lifescience Database Archive (English)

Full Text Available FS880233 FS880233_1_ORF2 88C10776BC024404 SUPERFAMILY SSF51621 Phosphoenolpyruvate/pyruva...te domain 1.9e-07 T IPR015813 Pyruvate/Phosphoenolpyruvate kinase, catalytic core Molecular Function: catalytic activity (GO:0003824) ...

Variations of Leaf Cuticular Waxes Among C3 and C4 Gramineae Herbs.

Science.gov (United States)

He, Yuji; Gao, Jianhua; Guo, Na; Guo, Yanjun

2016-11-01

Modern C4 plants are commonly distributed in hot and dry environments whereas C3 plants predominate in cool and shade areas. At the outmost of plant surface, the deposition and chemical composition of cuticular waxes vary under different environmental conditions. However, whether such variation of cuticular wax is related to the distribution of C3 and C4 under different environmental conditions is still not clear. In this study, leaves of six C3 Gramineae herbs distributed in spring, Roegneria kamoji, Polypogon fugax, Poa annua, Avena fatua, Alopecurus aequalis, and Oplismenus undulatifolius, and four C4 and one C3 Gramineae herbs distributed in summer, Digitaria sanguinalis, Eleusine indica, Setaria viridis, S. plicata, and O. undulatifolius, were sampled and analyzed for cuticular wax. Plates were the main epicuticular wax morphology in both C3 and C4 plants except S. plicata. The plates melted in C4 plants but not in C3 plants. The total cuticular wax amounts in C4 plants were significantly lower than those in C3 plants, except for O. undulatifolius. Primary alcohols were the most abundant compounds in C3 plants, whereas n-alkanes were relatively the most abundant compounds in C4 plants. C 29 was the most abundant n-alkane in C3 plants except for O. undulatifolius, whereas the most abundant n-alkane was C 31 or C 33 in C4 plants. The average chain length (ACL) of n-alkanes was higher in C4 than in C3 plants, whereas the ACL of n-alkanoic acids was higher in C3 than C4 plants. The cluster analysis based on the distribution of n-alkanes clearly distinguished C3 and C4 plants into two groups, except for O. undulatifolius which was grouped with C4 plants. These results suggest that the variations of cuticular waxes among C3 and C4 Gramineae herbs are related to the distribution of C3 and C4 plants under different environmental conditions. © 2016 Wiley-VHCA AG, Zurich, Switzerland.

Enhanced electrochemical performance of nano-sized LiFePO4/C synthesized by an ultrasonic-assisted co-precipitation method

International Nuclear Information System (INIS)

Liu Youyong; Cao Chuanbao

2010-01-01

A simple and effective method, the ultrasonic-assisted co-precipitation method, was employed to synthesize nano-sized LiFePO 4 /C. A glucose solution was used as the carbon source to produce in situ carbon to improve the conductivity of LiFePO 4 . Ultrasonic irradiation was adopted to control the size and homogenize the LiFePO 4 /C particles. The sample was characterized by X-ray powder diffraction, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). FE-SEM and TEM show that the as-prepared sample has a reduced particle size with a uniform size distribution, which is around 50 nm. A uniform amorphous carbon layer with a thickness of about 4-6 nm on the particle surface was observed, as shown in the HRTEM image. The electrochemical performance was demonstrated by the charge-discharge test and electrochemical impedance spectra measurements. The results indicate that the nano-sized LiFePO 4 /C presents enhanced discharge capacities (159, 147 and 135 mAh g -1 at 0.1, 0.5 and 2 C-rate, respectively) and stable cycling performance. This study offers a simple method to design and synthesis nano-sized cathode materials for lithium-ion batteries.

An in situ carbonization-replication method to synthesize mesostructured WO3/C composite as nonprecious-metal anode catalyst in PEMFC.

Science.gov (United States)

Cui, Xiangzhi; Hua, Zile; Wei, Chenyang; Shu, Zhu; Zhang, Liangxia; Chen, Hangrong; Shi, Jianlin

2013-02-01

A meostructured WO(3)/C composite with crystalline framework and high electric conductivity has been synthesized by a new in situ carbonization-replication route using the block copolymer (poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)) present in situ in the pore channels of mesoporous silica template as carbon source. X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, thermogravimetry differential thermal analysis, and N(2) adsorption techniques were adopted for the structural characterization. Cyclic voltammetry, chronoamperometry, and single-cell test for hydrogen electrochemical oxidation were adopted to characterize the electrochemical activities of the mesoporous WO(3)/C composite. The carbon content and consequent electric conductivity of these high-surface-area (108-130 m(2) g(-1)) mesostructured WO(3)/C composite materials can be tuned by variation of the duration of heat treatment, and the composites exhibited high and stable electrochemical catalytic activity. The single-cell test results indicated that the mesostructured WO(3)/C composites showed clear electrochemical catalytic activity toward hydrogen oxidation at 25 °C, which makes them potential non-precious-metal anode catalysts in proton exchange membrane fuel cell. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlling the Sn-C bonds content in SnO2@CNTs composite to form in situ pulverized structure for enhanced electrochemical kinetics.

Science.gov (United States)

Cheng, Yayi; Huang, Jianfeng; Qi, Hui; Cao, Liyun; Luo, Xiaomin; Li, Jiayin; Xu, Zhanwei; Yang, Jun

2017-12-07

The Sn-C bonding content between the SnO 2 and CNTs interface was controlled by the hydrothermal method and subsequent heat treatment. Electrochemical analysis found that the SnO 2 @CNTs with high Sn-C bonding content exhibited much higher capacity contribution from alloying and conversion reaction compared with the low content of Sn-C bonding even after 200 cycles. The high Sn-C bonding content enabled the SnO 2 nanoparticles to stabilize on the CNTs surface, realizing an in situ pulverization process of SnO 2 . The in situ pulverized structure was beneficial to maintain the close electrochemical contact of the working electrode during the long-term cycling and provide ultrafast transfer paths for lithium ions and electrons, which promoted the alloying and conversion reaction kinetics greatly. Therefore, the SnO 2 @CNTs composite with high Sn-C bonding content displayed highly reversible alloying and conversion reaction. It is believed that the composite could be used as a reference for design chemically bonded metal oxide/carbon composite anode materials in lithium-ion batteries.

Structural, bonding, anisotropic mechanical and thermal properties of Al4SiC4 and Al4Si2C5 by first-principles investigations

Directory of Open Access Journals (Sweden)

Liang Sun

2016-09-01

Full Text Available The structural, bonding, electronic, mechanical and thermal properties of ternary aluminum silicon carbides Al4SiC4 and Al4Si2C5 are investigated by first-principles calculations combined with the Debye quasi-harmonic approximation. All the calculated mechanical constants like bulk, shear and Young's modulus are in good agreement with experimental values. Both compounds show distinct anisotropic elastic properties along different crystalline directions, and the intrinsic brittleness of both compounds is also confirmed. The elastic anisotropy of both aluminum silicon carbides originates from their bonding structures. The calculated band gap is obtained as 1.12 and 1.04 eV for Al4SiC4 and Al4Si2C5 respectively. From the total electron density distribution map, the obvious covalent bonds exist between Al and C atoms. A distinct electron density deficiency sits between AlC bond along c axis among Al4SiC4, which leads to its limited tensile strength. Meanwhile, the anisotropy of acoustic velocities for both compounds is also calculated and discussed.

IN SITU Deposition of Fe-TiC Nanocomposite on Steel by Laser Cladding

Science.gov (United States)

Razavi, Mansour; Rahimipour, Mohammad Reza; Ganji, Mojdeh; Ganjali, Mansoreh; Gangali, Monireh

The possibility of deposition of Fe-TiC nanocomposite on the surface of carbon steel substrate with the laser coating method had been investigated. Mechanical milling was used for the preparation of raw materials. The mixture of milled powders was used as a coating material on the substrate steel surface and a CO2 laser was used in continuous mode for coating. Microstructural studies were performed by scanning electron microscopy. Determinations of produced phases, crystallite size and mean strain have been done by X-ray diffraction. The hardness and wear resistance of coated samples were measured. The results showed that the in situ formation of Fe-TiC nanocomposite coating using laser method is possible. This coating has been successfully used to improve the hardness and wear resistance of the substrate so that the hardness increased by about six times. Coated iron and titanium carbide crystallite sizes were in the nanometer scale.

Use of bioreactor landfill for nitrogen removal to enhance methane production through ex situ simultaneous nitrification-denitrification and in situ denitrification.

Science.gov (United States)

Sun, Xiaojie; Zhang, Hongxia; Cheng, Zhaowen

2017-08-01

High concentrations of nitrate-nitrogen (NO 3 - -N) derived from ex situ nitrification phase can inhibit methane production during ex situ nitrification and in situ denitrification bioreactor landfill. A combined process comprised of ex situ simultaneous nitrification-denitrification (SND) in an aged refuse bioreactor (ARB) and in situ denitrification in a fresh refuse bioreactor (FRB) was conducted to reduce the negative effect of high concentrationsof NO 3 - -N. Ex situ SND can be achieved because NO 3 - -N concentration can be reduced and the removal rate of ammonium-nitrogen (NH 4 + -N) remains largely unchanged when the ventilation rate of ARB-A2 is controlled. The average NO 3 - -N concentrations of effluent were 470mg/L in ex situ nitrification ARB-A1 and 186mg/L in ex situ SND ARB-A2. The average NH 4 + -N removal rates of ARB-A1 and ARB-A2 were 98% and 94%, respectively. Based on the experimental data from week 4 to week 30, it is predicted that NH 4 + -N concentration in FRB-F1 of the ex situ nitrification and in situ denitrification process would reach 25mg/L after 63weeks, and about 40weeks for the FRB-F2 of ex situ SND and in situ denitrification process . Ex situ SND and in situ denitrification process can improve themethane production of FRB-F2. The lag phase time of methane production for the FRB-F2 was 11weeks. This phase was significantly shorter than the 15-week phases of FRB-F1 in ex situ nitrification and in situ denitrification process. A seven-week stabilizationphase was required to increase methane content from 5% to 50% for FRB-F2. Methane content in FRB-F1 did not reach 50% but reached the 45% peak after 20weeks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental studies of collisions of excited Li(4p) atoms with C2H4, C2H6, C3H8 and theoretical interpretation of the Li-C2H4 system

International Nuclear Information System (INIS)

Semmineh, Natenael; Bililign, Solomon; Hagebaum-Reignier, Denis; Jeung, Gwang-Hi

2009-01-01

Collisions of excited Li(4p) states with C 2 H 4 , C 2 H 6 and C 3 H 8 are studied experimentally using far-wing scattering state spectroscopy techniques. High-level ab initio quantum mechanical studies of the Li-C 2 H 4 system are conducted to explain the results of the experiment for this system. The recent and present works indicate that knowledge of the internal structure of the perturber (C 2 H 4 , C 2 H 6 and C 3 H 8 ) is essential to fully understand the interaction between the metal and the hydrocarbon molecules. The ab initio calculation shows that the Li(4d) (with little probability under the experimental conditions) and the Li(4p) can be formed directly through the laser pumping. It also shows that the Li(4s) and Li(3d) states can be formed through an electronic diabatic coupling involving a radiationless process. However, the Li(3p), Li(3s) and Li(2p) states can only be formed through a secondary diabatic coupling which is a much less probable process than the primary one. The calculation limited to two C 2v sections of the potential energy surfaces (PESs) shows peculiar multi-state crossings that we have never seen in other lithium complexes we studied

In-SITU Raman Spectroscopy of Single Microparticle Li-Intercalation Electrodes

Science.gov (United States)

Dokko, Kaoru; Shi, Qing-Fang; Stefan, Ionel C.; Scherson, Daniel A.

2003-01-01

Modifications in the vibrational properties of a single microparticle of LiMn2O4 induced by extraction and subsequent injection of Li(+) into the lattice have been monitored in situ via simultaneous acquisition of Raman scattering spectra and cyclic voltammetry data in 1M LiC1O4 solutions in ethylene carbonate (EC):diethyl carbonate (DEC) mixtures (1:1 by volume). Statistical analyses of the spectra in the range 15 < SOD < 45%, where SOD represents the state of discharge (in percent) of the nominally fully charged material, i.e. lambda-MnO2, were found to be consistent with the coexistence of two distinct phases of lithiated metal oxide in agreement with information derived from in situ X-ray diffraction (XRD) measurements involving more conventional battery-type electrodes.

InterProScan Result: FS895314 [KAIKOcDNA[Archive

Lifescience Database Archive (English)

Full Text Available FS895314 FS895314_5_ORF1 97DB8176F1361E8C SUPERFAMILY SSF51621 Phosphoenolpyruvate/pyruva...te domain 1e-21 T IPR015813 Pyruvate/Phosphoenolpyruvate kinase, catalytic core Molecular Function: catalytic activity (GO:0003824) ...

Effect of homogeneity of particle distribution on tensile crack propagation in mushy state rolled in situ Al–4.5Cu–5TiB2 particulate composite

International Nuclear Information System (INIS)

Jana, A.; Siddhalingeshwar, I.G.; Mitra, R.

2013-01-01

The effect of mushy state rolling with 20 vol% liquid at 626 °C for 5% thickness reduction per pass on homogeneity of TiB 2 and CuAl 2 particle distribution in the in situ Al–4.5Cu–5TiB 2 composite has been examined. These particles, appearing as segregated at grain boundaries in the as-cast composite, are redistributed on mushy state rolling. The homogeneity of particle distribution has been quantitatively evaluated by developing a computer program for multi-scalar analysis of area-fractions in scanning electron microscope (SEM) images to estimate homogeneous length scales. The optimum homogeneity is found in the composite subjected to two mushy state roll passes. The matrix microhardness increases with decrease in the homogeneous length scale. In situ tensile straining experiments inside SEM have shown linkage of particle–matrix interfacial microcracks at particle-clusters as fracture mechanism in as-cast or 4-pass mushy state rolled composites. In contrast, crack propagation through matrix is favored in the 2-pass mushy state rolled composite

Reducing HAuCl4 by the C60 dianion: C60-directed self-assembly of gold nanoparticles into novel fullerene bound gold nanoassemblies

International Nuclear Information System (INIS)

Liu Wei; Gao Xiang

2008-01-01

The C 60 dianion is used to reduce tetrachloroauric acid (HAuCl 4 ) for the first time; three-dimensional C 60 bound gold (Au-C 60 ) nanoclusters are obtained from C 60 -directed self-assembly of gold nanoparticles due to the strong affinities of Au-C 60 and C 60 -C 60 . The process was monitored in situ by UV-vis-NIR spectroscopy. The resulting Au-C 60 nanoclusters were characterized using transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive spectroscopy (EDS), x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and FT-IR and Raman spectroscopies. TEM demonstrates the formation of 3D nanonetwork aggregates, which are composed of discrete gold nanocores covered with a C 60 monolayer. The SAED and XRD patterns indicate that the gold nanocores inside the capped C 60 molecules belong to the face-centred cubic crystal structure, while the C 60 molecules are amorphous. The EDS and XPS measurements validate that the Au-C 60 nanoclusters contain only Au and C elements and Au 3+ is reduced to Au 0 . FT-IR spectroscopy shows the chemiadsorption of C 60 to the gold nanocores, while Raman spectroscopy demonstrates the electron transfer from the gold nanocores to the chemiadsorbed C 60 molecules. Au-C 60 nanoclusters embedded in tetraoctyl-n-ammonium bromide (TOAB) on glassy carbon electrodes (GCEs) have been fabricated and have shown stable and well-defined electrochemical responses in aqueous solution

The superfamily of C3b/C4b-binding proteins

DEFF Research Database (Denmark)

Kristensen, Torsten; D'Eustachio, P; Ogata, R T

1987-01-01

The determination of primary structures by amino acid and nucleotide sequencing for the C3b-and/or C4b-binding proteins H, C4BP, CR1, B, and C2 has revealed the presence of a common structural element. This element is approximately 60 amino acids long and is repeated in a tandem fashion, commencing...... at the amino-terminal end of each molecule. Two other complement components, C1r and C1s, have two of these repeating units in the carboxy-terminal region of their noncatalytic A chains. Three noncomplement proteins, beta 2-glycoprotein I (beta 2I), the interleukin 2 receptor (IL 2 receptor), and the b chain...... of factor XIII, have 4, 2 and 10 of these repeating units, respectively. These proteins obviously belong to the above family, although there is no evidence that they interact with C3b and/or C4b. Human haptoglobin and rat leukocyte common antigen also contain two and three repeating units, respectively...

Revealing diversity in structural and biochemical forms of C4 photosynthesis and a C3–C4 intermediate in genus Portulaca L. (Portulacaceae)

Science.gov (United States)

Voznesenskaya, Elena V.; Koteyeva, Nuria K.; Edwards, Gerald E.; Ocampo, Gilberto

2010-01-01

Portulacaceae is one of 19 families of terrestrial plants in which species having C4 photosynthesis have been found. Representative species from major clades of the genus Portulaca were studied to characterize the forms of photosynthesis structurally and biochemically. The species P. amilis, P. grandiflora, P. molokiniensis, P. oleracea, P. pilosa, and P. umbraticola belong to the subgenus Portulaca and are C4 plants based on leaf carbon isotope values, Kranz anatomy, and expression of key C4 enzymes. Portulaca umbraticola, clade Umbraticola, is NADP-malic enzyme (NADP-ME)-type C4 species, while P. oleracea and P. molokiniensis in clade Oleracea are NAD-ME-type C4 species, all having different forms of Atriplicoid-type leaf anatomy. In clade Pilosa, P. amilis, P. grandiflora, and P. pilosa are NADP-ME-type C4 species. They have Pilosoid-type anatomy in which Kranz tissues enclose peripheral vascular bundles with water storage in the centre of the leaf. Portulaca cf. bicolor, which belongs to subgenus Portulacella, is an NADP-ME C4 species with Portulacelloid-type anatomy; it has well-developed Kranz chlorenchyma surrounding lateral veins distributed in one plane under the adaxial epidermis with water storage cells underneath. Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C3–C4 based on its intermediate CO2 compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells. The C4 Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C3-type photosynthetic cells. The results indicate that multiple structural and biochemical forms of C4 photosynthesis evolved in genus Portulaca. PMID:20591900

In situ depletion of CD4(+) T cells in human skin by Zanolimumab

DEFF Research Database (Denmark)

Villadsen, L.S.; Skov, L.; Dam, T.N.

2007-01-01

CD4(+) T cells, in activated or malignant form, are involved in a number of diseases including inflammatory skin diseases such as psoriasis, and T cell lymphomas such as the majority of cutaneous T cell lymphomas (CTCL). Targeting CD4 with an antibody that inhibits and/or eliminates disease......-driving T cells in situ may therefore be a useful approach in the treatment of inflammatory and malignant skin diseases. Depletion of CD4(+) T cells in intact inflamed human skin tissue by Zanolimumab, a fully human therapeutic monoclonal antibody (IgG1, kappa) against CD4, was studied in a human psoriasis......(+), but not CD8(+) CD3(+) T cells. The capacity of Zanolimumab to deplete the CD4(+) T cells in the skin may be of importance in diseases where CD4(+) T cells play a central role. Indeed, in a phase II clinical trial Zanolimumab has shown a dose-dependent clinical response in patients with CTCL and the antibody...

In situ QXAFS observation of the reduction of Fe2O3 and CaFe2O4

International Nuclear Information System (INIS)

Kimura, Masao; Takayama, Toru; Murao, Reiko; Nomura, Masaharu; Uemura, Yohei; Asakura, Kiyotaka

2013-01-01

In situ QXAFS studies of the reduction of α-Fe 2 O 3 and CaFe 2 O 4 were conducted to determine their reduction kinetics and mechanisms. The reduction of α-Fe 2 O 3 involved two steps, the first being a very fast process in which Fe 3+ was reduced to Fe 2+ and the second being the reduction of Fe 2+ to Fe metal over a longer period. In contrast, the reduction of Fe in CaFe 2 O 4 was a single first-order reaction, although an induction period was clearly observed at the beginning of the reduction process. The reduction processes were successfully studied using a combination of in situ QXAFS spectra at the Ca and Fe K-edges.

Microstructure of a Ni Matrix Composite Coating Reinforced by In-situ TiC Particles Using Plasma Cladding

Institute of Scientific and Technical Information of China (English)

WUYu-ping; WANGZe-hua; LINPing-hua

2004-01-01

Plasma cladding process was used to prepare the TiC/Ni composite coating on the mild steel substrates. The TiC particles were synthesized in-situ. Microstructure and properties of the coating were investigated by optical microscopy, X-Ray diffraction, SEM, TEM and microhardness tester. The results show that the interface between the coating and the substrate is metallurgically bonded. The coating was uniform and almost defect-free when [Ti+C] varied from 10% to 20% after ball milling. The microstructure of the coating is mainly composed of γ-Ni dendrite, interdendritic eutectic (γ-Ni austenite, M23C6 and CrB) and TiC particles. Most of the TiC particles are spherical and a small fraction is blocky in size of 1-2μm. The TiC particles are smaller at the bottom than near the top of the coating. The coating has a gradient microstructure and a highest hardness of 1000Hv0.1.

Evolution of the argillite / CEM I interface at 70 C.: in situ tests and modelling results

International Nuclear Information System (INIS)

Lalan, P.; Dauzeres, A.; Barker, E.; De Windt, L.; Detilleux, V.; Desveaux, P.

2015-01-01

French radioactive waste disposal concept involves cementitious materials in a clayey host-rock. The presence of exothermic wastes in the storage cells may induce a temperature of about 70 Celsius degrees at the material interfaces. At present, experiment thermal conditions have been undertaken at about 20 C. degrees and studies at higher temperature are really scarce, especially experiments considering diffusion through the cement / clay interface. The still on-going study presented here is focusing on argillite / CEM-I interface. A one-year experiment under in situ conditions at the Tournemire experimental station (IRSN) was carried out and meanwhile, preliminary reactive transport modelling with HYTEC helped to understand the impact of a high temperature on the physico-chemical behaviour of cement / clay interface. The first results showed decalcification of cement and diffuse carbonation as well as a possible illite precipitation of clay-type phases. A C-S-H ribbon appeared at the interface between the two materials and a layer grew between the C-S-H ribbon and the cementitious material. This layer contained zeolites and behaved as a diffusive barrier. After one year of in situ interactions, the disturbance thickness was about 350 microns in CEM-I cement paste and about 100 microns in argillite. The modelling reproduced relatively well the experimentally observed processes but the extension of the disturbance is too wide and the zeolite layer is misplaced according to the experimental observations. This study highlights the lack of data at highest temperature on the reaction kinetics, diffusion coefficients but also on porosity variations. (authors)

Sintering process optimization for multi-layer CGO membranes by in situ techniques

DEFF Research Database (Denmark)

Kaiser, Andreas; Prasad, A.S.; Foghmoes, Søren Preben Vagn

2013-01-01

The sintering of asymmetric CGO bi-layers (thin dense membrane on a porous support; Ce0.9Gd0.1O1.95-delta = CGO) with Co3O4 as sintering additive has been optimized by combination of two in situ techniques. Optical dilatometry revealed that bi-layer shape and microstructure are dramatically...... changing in a narrow temperature range of less than 100 degrees C. Below 1030 degrees C, a higher densification rate in the dense membrane layer than in the porous support leads to concave shape, whereas the densification rate of the support is dominant above 1030 degrees C, leading to convex shape. A fiat...... bi-layer could be prepared at 1030 degrees C, when shrinkage rates were similar. In situ van der Pauw measurements on tape cast layers during sintering allowed following the conductivity during sintering. A strong increase in conductivity and in activation energy E-a for conduction was observed...

Microstructure and wear property of the Ti5Si3/TiC reinforced Co-based coatings fabricated by laser cladding on Ti-6Al-4V

Science.gov (United States)

Weng, Fei; Yu, Huijun; Liu, Jianli; Chen, Chuanzhong; Dai, Jingjie; Zhao, Zhihuan

2017-07-01

Ti5Si3/TiC reinforced Co-based composite coatings were fabricated on Ti-6Al-4V titanium alloy by laser cladding with Co42 and SiC mixture. Microstructure and wear property of the cladding coatings with different content of SiC were investigated. During the cladding process, the original SiC dissolved and reacted with Ti forming Ti5Si3 and TiC. The complex in situ formed phases were found beneficial to the improvement of the coating property. Results indicated that the microhardness of the composite coatings was enhanced to over 3 times the substrate. The wear resistance of the coatings also showed distinct improvement (18.4-57.4 times). More SiC gave rise to better wear resistance within certain limits. However, too much SiC (20 wt%) was not good for the further improvement of the wear property.

Toward Protein Structure In Situ: Comparison of Two Bifunctional Rhodamine Adducts of Troponin C

Science.gov (United States)

Julien, Olivier; Sun, Yin-Biao; Knowles, Andrea C.; Brandmeier, Birgit D.; Dale, Robert E.; Trentham, David R.; Corrie, John E. T.; Sykes, Brian D.; Irving, Malcolm

2007-01-01

As part of a program to develop methods for determining protein structure in situ, sTnC was labeled with a bifunctional rhodamine (BR or BSR), cross-linking residues 56 and 63 of its C-helix. NMR spectroscopy of the N-terminal domain of BSR-labeled sTnC in complex with Ca2+ and the troponin I switch peptide (residues 115–131) showed that BSR labeling does not significantly affect the secondary structure of the protein or its dynamics in solution. BR-labeling was previously shown to have no effect on the solution structure of this complex. Isometric force generation in isolated demembranated fibers from rabbit psoas muscle into which BR- or BSR-labeled sTnC had been exchanged showed reduced Ca2+-sensitivity, and this effect was larger with the BSR label. The orientation of rhodamine dipoles with respect to the fiber axis was determined by polarized fluorescence. The mean orientations of the BR and BSR dipoles were almost identical in relaxed muscle, suggesting that both probes accurately report the orientation of the C-helix to which they are attached. The BSR dipole had smaller orientational dispersion, consistent with less flexible linkers between the rhodamine dipole and cysteine-reactive groups. PMID:17483167