WorldWideScience

Sample records for carbon 13 target

  1. Synthesis of carbon-13-labeled tetradecanoic acids.

    Science.gov (United States)

    Sparrow, J T; Patel, K M; Morrisett, J D

    1983-07-01

    The synthesis of tetradecanoic acid enriched with 13C at carbons 1, 3, or 6 is described. The label at the carbonyl carbon was introduced by treating 1-bromotridecane with K13CN (90% enriched) to form the 13C-labeled nitrile, which upon hydrolysis yielded the desired acid. The [3-13C]tetradecanoic acid was synthesized by alkylation of diethyl sodio-malonate with [1-13C]1-bromododecane; the acid was obtained upon saponification and decarboxylation. The label at the 6 position was introduced by coupling the appropriately labeled alkylcadmium chloride with the half acid chloride methyl ester of the appropriate dioic acid, giving the corresponding oxo fatty acid ester. Formation of the tosylhydrazone of the oxo-ester followed by reduction with sodium cyanoborohydride gave the labeled methyl tetradecanoate which, upon hydrolysis, yielded the desired tetradecanoic acid. All tetradecanoic acids were identical to unlabeled analogs as evaluated by gas-liquid chromatography and infrared or NMR spectroscopy. These labeled fatty acids were used subsequently to prepare the correspondingly labeled diacyl phosphatidylcholines. PMID:6631228

  2. Ultra-rapid targeted analysis of 40 drugs of abuse in oral fluid by LC-MS/MS using carbon-13 isotopes of methamphetamine and MDMA to reduce detector saturation.

    Science.gov (United States)

    Di Rago, Matthew; Chu, Mark; Rodda, Luke N; Jenkins, Elizabeth; Kotsos, Alex; Gerostamoulos, Dimitri

    2016-05-01

    The number of oral fluid samples collected by the road policing authority in Victoria, Australia, requiring confirmatory laboratory analysis for drugs proscribed under Victorian legislation (methamphetamine, MDMA and Δ9-tetrahydrocannabinol) has greatly increased in recent years, driving the need for improved analysis techniques to enable expedient results. The aim of this study was to develop an LC-MS/MS-based targeted oral fluid screening technique that covers a broad range of basic and neutral drugs of abuse that can satisfy increased caseload while monitoring other compounds of interest for epidemiological purposes. By combining small sample volume, simple extraction procedure, rapid LC-MS/MS analysis and automated data processing, 40 drugs of abuse including amphetamines, benzodiazepines, cocaine and major metabolites, opioids, cannabinoids and some designer stimulants were separated over 5 min (with an additional 0.5 min re-equilibration time). The analytes were detected using a Sciex® API 4500 Q-Trap LC-MS/MS system with positive ESI in MRM mode monitoring three transitions per analyte. The method was fully validated in accordance with international guidelines and also monitored carbon-13 isotopes of MDMA and MA to reduce detector saturation effects, allowing for confirmation of large concentrations of these compounds without the need for dilution or re-analysis. The described assay has been successfully used for analysis of oral fluid collected as part of law enforcement procedures at the roadside in Victoria, providing forensic results as well as epidemiological prevalence in the population tested. The fast and reliable detection of a broad range of drugs and subsequent automated data processing gives the opportunity for high throughput and fast turnaround times for forensic toxicology.

  3. Ultra-rapid targeted analysis of 40 drugs of abuse in oral fluid by LC-MS/MS using carbon-13 isotopes of methamphetamine and MDMA to reduce detector saturation.

    Science.gov (United States)

    Di Rago, Matthew; Chu, Mark; Rodda, Luke N; Jenkins, Elizabeth; Kotsos, Alex; Gerostamoulos, Dimitri

    2016-05-01

    The number of oral fluid samples collected by the road policing authority in Victoria, Australia, requiring confirmatory laboratory analysis for drugs proscribed under Victorian legislation (methamphetamine, MDMA and Δ9-tetrahydrocannabinol) has greatly increased in recent years, driving the need for improved analysis techniques to enable expedient results. The aim of this study was to develop an LC-MS/MS-based targeted oral fluid screening technique that covers a broad range of basic and neutral drugs of abuse that can satisfy increased caseload while monitoring other compounds of interest for epidemiological purposes. By combining small sample volume, simple extraction procedure, rapid LC-MS/MS analysis and automated data processing, 40 drugs of abuse including amphetamines, benzodiazepines, cocaine and major metabolites, opioids, cannabinoids and some designer stimulants were separated over 5 min (with an additional 0.5 min re-equilibration time). The analytes were detected using a Sciex® API 4500 Q-Trap LC-MS/MS system with positive ESI in MRM mode monitoring three transitions per analyte. The method was fully validated in accordance with international guidelines and also monitored carbon-13 isotopes of MDMA and MA to reduce detector saturation effects, allowing for confirmation of large concentrations of these compounds without the need for dilution or re-analysis. The described assay has been successfully used for analysis of oral fluid collected as part of law enforcement procedures at the roadside in Victoria, providing forensic results as well as epidemiological prevalence in the population tested. The fast and reliable detection of a broad range of drugs and subsequent automated data processing gives the opportunity for high throughput and fast turnaround times for forensic toxicology. PMID:26993306

  4. Selective carbon 13 enrichment of side chain carbons of ginkgo lignin traced by carbon 13 nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Although carbon 13 nuclear magnetic resonance spectroscopy (13C-NMR) is widely used in lignin structural studies, serious difficulties are encountered in the assignments of 13C signals because of their extensive overlaps resulting from the complex structure of lignin and of delicate detection of minor structures. To overcome these difficulties, specifically 13C-enriched precursors of lignin biosynthesis, coniferin-[side chain-β-13C] and coniferin-[side chain-γ-13C], were administered to growing stems of ginkgo (Ginkgo biloba). The NMR analysis of the milled wood lignins isolated from the newly formed xylem showed that selective enrichment of specific carbons of protolignin in the cell wall was achieved without seriously disturbing the lignin biosynthesis. The presence of saturated methylene side chains in the protolignin was shown for the first time by this selective enrichment technique in combination with NMR analysis. (authors). 23 refs., 3 figs., 1 tab

  5. Selective carbon 13 enrichment of side chain carbons of ginkgo lignin traced by carbon 13 nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Y. (Nagoya Univ. (Japan). Faculty of Agriculture); Robert, D.R. (CEA Centre d' Etudes de Grenoble, 38 (France). Dept. de Recherche Fondamentale sur la Matiere Condensee); Terashima, N. (Forest Products Lab., Madison, WI (United States))

    Although carbon 13 nuclear magnetic resonance spectroscopy ([sup 13]C-NMR) is widely used in lignin structural studies, serious difficulties are encountered in the assignments of [sup 13]C signals because of their extensive overlaps resulting from the complex structure of lignin and of delicate detection of minor structures. To overcome these difficulties, specifically [sup 13]C-enriched precursors of lignin biosynthesis, coniferin-[side chain-[beta]-[sup 13]C] and coniferin-[side chain-[gamma]-[sup 13]C], were administered to growing stems of ginkgo (Ginkgo biloba). The NMR analysis of the milled wood lignins isolated from the newly formed xylem showed that selective enrichment of specific carbons of protolignin in the cell wall was achieved without seriously disturbing the lignin biosynthesis. The presence of saturated methylene side chains in the protolignin was shown for the first time by this selective enrichment technique in combination with NMR analysis. (authors). 23 refs., 3 figs., 1 tab.

  6. Concomitant oxygen-18 enrichment in commercial carbon-13 labelled urea

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Katsumi; Chiyoda, Takeshi; Kajiwara, Masahiro [Meiji College of Pharmacy, Tokyo (Japan). Dept. of Medicinal Chemistry

    1996-12-01

    By mass spectroscopy, 50-fold oxygen-18 enrichment over natural abundance was observed in commercial {sup 13}C-urea (99 atom % {sup 13}C) synthesized from {sup 13}C-carbon monoxide that had been {sup 13}C-enriched by cryogenic distillation. In contrast, {sup 13}C-urea synthesized from {sup 13}C-potassium cyanide (a {sup 13}C-labelled compound having no oxygen atom) showed the natural abundance level of oxygen-18. (author).

  7. The prospects for polarized target materials with pure carbon background

    International Nuclear Information System (INIS)

    None of the materials presently in common use for polarized proton targets has a pure carbon nuclear background. The alcohols and diols contain some oxygen, and the ammonia and amine-based materials contain nitrogen and/or other noncarbon species. In the latter cases the noncarbon nuclei are measurably polarized as a concomitant of the process used to polarize the hydrogen nuclei. The relative simplicity of a pure carbon background would be advantageous for most types of scattering experiments and perhaps crucial for some. In addition to simplifying the kinematics of background events, pure carbon is relatively easy to prepare as a ''dummy'' target for background subtraction. Also, in such a target material, 13C-enrichment would yield a clean polarized 13C material. In this note I explore the possibilities for such materials, touching upon only what I consider to be the ''high'' points. The subject matter is capable of nearly endless ramification and speculation. In fact, owing to a general lack of relevant experimental data, even this relatively brief note contains much that is speculative to some degree

  8. Coastal climate reflected in carbon-13/carbon-12 ratio of organic carbon in varved sediment from Santa Barbara basin

    OpenAIRE

    Schimmelmann, Arndt; Tegner, Mia J.

    1991-01-01

    A 1844-1987 time-series of carbon stable isotope ratios from dated sedimentary total organic carbon from the center of the Santa Barbara basin is compared with historical climate and oceanographic records. Carbon derived from carbon-13-depleted phytoplankton and carbon-13-enriched kelp appear responsible for a large part of the isotopic variance in sedimentary total organic carbon. El Niño/Southern Oscillation events are recorded by the isotopic response of marine organic carbon in sediments.

  9. Laser ablation of carbon targets placed in a liquid

    Science.gov (United States)

    Antipov, A. A.; Arakelyan, S. M.; Garnov, S. V.; Kutrovskaya, S. V.; Kucherik, A. O.; Nogtev, D. S.; Osipov, A. V.

    2015-08-01

    We report experimental results on laser formation of carbon nanostructures produced during irradiation of a target placed in water. We have performed comparative experiments on laser heating of carbon targets by millisecond and femtosecond laser pulses. It is shown that under different conditions of laser irradiation of targets made of schungite, glassy carbon and pyrolytic graphite, different morphological types of micro- and nanostructured carbon are formed.

  10. Carbon-13 NMR spectroscopy of biological systems

    CERN Document Server

    Beckmann, Nicolau

    1995-01-01

    This book is intended to provide an in-depth understanding of 13C NMR as a tool in biological research. 13C NMR has provided unique information concerning complex biological systems, from proteins and nucleic acids to animals and humans. The subjects addressed include multidimensional heteronuclear techniques for structural studies of molecules in the liquid and solid states, the investigation of interactions in model membranes, the elucidation of metabolic pathwaysin vitro and in vivo on animals, and noninvasive metabolic studies performed on humans. The book is a unique mix of NMR methods and biological applications which makes it a convenient reference for those interested in research in this interdisciplinary area of physics, chemistry, biology, and medicine.Key Features* An interdisciplinary text with emphasis on both 13C NMR methodology and the relevant biological and biomedical issues* State-of-the-art 13C NMR techniques are described; Whenever possible, their advantages over other approaches are empha...

  11. Caveolin interaction governs Kv1.3 lipid raft targeting.

    Science.gov (United States)

    Pérez-Verdaguer, Mireia; Capera, Jesusa; Martínez-Mármol, Ramón; Camps, Marta; Comes, Núria; Tamkun, Michael M; Felipe, Antonio

    2016-03-02

    The spatial localization of ion channels at the cell surface is crucial for their functional role. Many channels localize in lipid raft microdomains, which are enriched in cholesterol and sphingolipids. Caveolae, specific lipid rafts which concentrate caveolins, harbor signaling molecules and their targets becoming signaling platforms crucial in cell physiology. However, the molecular mechanisms involved in such spatial localization are under debate. Kv1.3 localizes in lipid rafts and participates in the immunological response. We sought to elucidate the mechanisms of Kv1.3 surface targeting, which govern leukocyte physiology. Kv1 channels share a putative caveolin-binding domain located at the intracellular N-terminal of the channel. This motif, lying close to the S1 transmembrane segment, is situated near the T1 tetramerization domain and the determinants involved in the Kvβ subunit association. The highly hydrophobic domain (FQRQVWLLF) interacts with caveolin 1 targeting Kv1.3 to caveolar rafts. However, subtle variations of this cluster, putative ancillary associations and different structural conformations can impair the caveolin recognition, thereby altering channel's spatial localization. Our results identify a caveolin-binding domain in Kv1 channels and highlight the mechanisms that govern the regulation of channel surface localization during cellular processes.

  12. Fungal Taxa Target Different Carbon Substrates in Harvard Forest Soils

    Science.gov (United States)

    Hanson, C. A.; Allison, S. D.; Wallenstein, M. D.; Mellilo, J. M.; Treseder, K. K.

    2006-12-01

    The mineralization of soil organic carbon is a major component of the global carbon cycle and is largely controlled by soil microbial communities. However, little is known about the functional roles of soil microbes or whether different microbial taxa target different carbon substrates under natural conditions. To examine this possibility, we assessed the community composition of active fungi by using a novel nucleotide analog technique in soils from the Harvard Forest. We hypothesized that fungal community composition would shift in response to the addition of different substrates and that specific fungal taxa would respond differentially to particular carbon sources. To test this hypothesis, we added a nucleotide analog probe directly to soils in conjunction with one of five carbon compounds of increasing recalcitrance: glycine, sucrose, cellulose, tannin-protein complex, and lignin. During 48 hour incubations, the nucleotide analog was incorporated into newly replicated DNA of soil organisms that proliferated following the addition of the substrates. In this way, we labeled the DNA of microbes that respond to a particular carbon source. Labeled DNA was isolated and fungal Internal Transcribed Spacer (ITS) regions of ribosomal DNA (rDNA) were sequenced and analyzed to identify active fungi to near-species resolution. Diversity analyses at the ≥97% sequence similarity level indicated that taxonomic richness was greater under cellulose (Shannon Index: 3.23 ± 0.11 with ± 95% CI) and lignin (2.87 ± 0.15) additions than the other treatments (2.34 ± 0.16 to 2.64 ± 0.13). In addition, community composition of active fungi shifted under glycine, sucrose, and cellulose additions. Specifically, the community under glycine was significantly different from communities under control, cellulose, and tannin-protein (Ptannin-protein and slightly increased in response to lignin and sucrose. This confirms our hypothesis that particular taxa respond differently to specific

  13. Carbon-13 NMR studies of liquid crystals

    International Nuclear Information System (INIS)

    High resolution, proton decoupled 13C nmr are observed for a series of neat nematic liquid crystals, the p-alkoxyazoxybenzenes, and a smectic-A liquid crystal, diethylazoxydibenzoate in a magnetic field of 23 kG. The (uniaxial) order parameters S = less than P2(costheta) greater than are found to be about 0.4 and 0.9 for the nematic and smectic-A phase respectively at the clearing points. The order parameter increases with decreasing temperature in the nematic phase but is constant, or nearly so, with temperature in the smectic-A phase. In the nematic series studied, the ordering exhibits an even-odd alternation along the series and qualitative agreement with a recent theory due to Marcelja is found. In both phases, the spectra show that the molecule rotates rapidly about its long axis. Tentative conclusions about molecular conformational motion and 14N spin relaxation are presented for both nematic and smectic-A phases. In the smectic-A phase, the sample is rotated about an axis perpendicular to H0 and the resulting spectra are dicusssed. The theory of observed chemical shifts in liquid crystals is discussed and equations are derived which relate the nmr spectra of liquid-crystals to the order parameters. A model for the smectic-C phase due to Luz and Meiboom and Doane is described and lineshapes are determined on the basis of this model for special cases. The dependence of the order parameters on the molecular potential which give rise to the various degrees of order in the different liquid crystalline phases is examined. To a good approximation the functional dependence of the order parameters on the molecular potential is shown to be a simple one in the limit of small tilt angle in the smectic-C phase

  14. Anomalous 13C enrichment in modern marine organic carbon

    Science.gov (United States)

    Arthur, M.A.; Dean, W.E.; Claypool, G.E.

    1985-01-01

    Marine organic carbon is heavier isotopically (13C enriched) than most land-plant or terrestrial organic C1. Accordingly, ??13C values of organic C in modern marine sediments are routinely interpreted in terms of the relative proportions of marine and terrestrial sources of the preserved organic matter2,3. When independent geochemical techniques are used to evaluate the source of organic matter in Cretaceous or older rocks, those rocks containing mostly marine organic C are found typically to have lighter (more-negative) ??13C values than rocks containing mostly terrestrial organic C. Here we conclude that marine photosynthesis in mid-Cretaceous and earlier oceans generally resulted in a greater fractionation of C isotopes and produced organic C having lighter ??13C values. Modern marine photosynthesis may be occurring under unusual geological conditions (higher oceanic primary production rates, lower PCO2) that limit dissolved CO2 availability and minimize carbon isotope fractionation4. ?? 1985 Nature Publishing Group.

  15. Carbonic anhydrases as targets for medicinal chemistry.

    Science.gov (United States)

    Supuran, Claudiu T; Scozzafava, Andrea

    2007-07-01

    Carbonic anhydrases (CAs, EC 4.2.1.1) are zinc enzymes acting as efficient catalysts for the reversible hydration of carbon dioxide to bicarbonate. 16 different alpha-CA isoforms were isolated in mammals, where they play crucial physiological roles. Some of them are cytosolic (CA I, CA II, CA III, CA VII, CA XIII), others are membrane-bound (CA IV, CA IX, CA XII, CA XIV and CA XV), CA VA and CA VB are mitochondrial, and CA VI is secreted in saliva and milk. Three acatalytic forms are also known, the CA related proteins (CARP), CARP VIII, CARP X and CARP XI. Representatives of the beta-delta-CA family are highly abundant in plants, diatoms, eubacteria and archaea. The catalytic mechanism of the alpha-CAs is understood in detail: the active site consists of a Zn(II) ion co-ordinated by three histidine residues and a water molecule/hydroxide ion. The latter is the active species, acting as a potent nucleophile. For beta- and gamma-CAs, the zinc hydroxide mechanism is valid too, although at least some beta-class enzymes do not have water directly coordinated to the metal ion. CAs are inhibited primarily by two classes of compounds: the metal complexing anions and the sulfonamides/sulfamates/sulfamides possessing the general formula RXSO(2)NH(2) (R=aryl; hetaryl; perhaloalkyl; X=nothing, O or NH). Several important physiological and physio-pathological functions are played by CAs present in organisms all over the phylogenetic tree, related to respiration and transport of CO(2)/bicarbonate between metabolizing tissues and the lungs, pH and CO(2) homeostasis, electrolyte secretion in a variety of tissues/organs, biosynthetic reactions, such as the gluconeogenesis and ureagenesis among others (in animals), CO(2) fixation (in plants and algae), etc. The presence of these ubiquitous enzymes in so many tissues and in so different isoforms represents an attractive goal for the design of inhibitors with biomedical applications. Indeed, CA inhibitors are clinically used as

  16. Isotopic composition of carbon-13 and oxygen-18 from authigenic carbonates, Black Sea region

    Science.gov (United States)

    Logvina, E.; Mazurenko, L.; Prasolov, E.

    2004-05-01

    Several types of authigenic carbonates related to the fluid discharge zones were sampled during the international expeditions onboard R/V "Professor Vodyanitskiy" (56th cruise) and R/V "Professor Logachev" (11th cruise of UNESCO-TTR) in the northwest part of the Black sea. These carbonates are represented as mounds, build-ups and chimney-like structures, cemented sediments, crusts and concretions. The isotope analyses of carbonates were conducted using mass-spectrometer MS-20 in the Laboratory of Isotope Geology (St.Petersburg State University). The obtained values of oxygen-18 varied from +0,6 to -1,9 per mille (up to C0.8 per mille on average). This value is corresponding to normal seawater oxygen-18 value (about 0 per mille); we suspect, that the source of oxygen for carbonate formation is the seawater. The carbonates are characterized by low carbon-13 (from -35,4 to -42,6 per mille) in comparison with normal marine carbonates (about 0 per mille). We have reason to suppose that carbonates associated with fluid venting were formed by light isotopic composition of carbon dioxide (carbon-13 -45 to -52 per mille), which forming under methane microbiologic oxidation with such isotopic composition. This is because of crossing fluid process of carbon dioxide to carbonate with 8~10 degrees temperature carbon became heaver to 10- 11 per mille. The isotopic composition study of carbonate build-ups is of interest because its association with the gas hydrate accumulations is quite often in the gas seeps. This work is financially supported by Russian Foundation for Basic Research, grant 02-05-64346.

  17. Oxygen-18 and carbon-13 in the carbonates of the Salina formation of southwestern Ontario

    Energy Technology Data Exchange (ETDEWEB)

    O' Shea, K.J.; Miles, M.C.; Fritz, P.; Frape, S.K.; Lawson, D.E.

    1988-02-01

    The oxygen and carbon isotopic composition of the carbonates of the Upper Silurian Salina formation of the Michigan Basin was investigated to aid in interpretation of depositional environments. /sup 13/C results indicate that a change from generally anoxic bottom conditions to oxic conditions occurred during deposition of the salt and anhydrite evaporite unit. The lower organic-rich carbonate units were deposited in a shallow-water, evaporitic setting, most likely adjacent to a sabkha-type environment. A positive water balance maintained the anoxic conditions and buffered the carbon isotopes. Above the salt and anhydrite evaporite, the isotopic composition suggests that the development of a similar depositional environment, a sub-aerial prograding sabkha, occurred over wide areas of the basin. /sup 18/O results support the conclusion that Silurian oceans were depleted in /sup 18/O with respect to modern oceans by 5-6%. 56 refs., 13 figs., 4 tabs.

  18. Terrestrial carbon storage dynamics: Chasing a moving target

    Science.gov (United States)

    Luo, Y.; Shi, Z.; Jiang, L.; Xia, J.; Wang, Y.; Kc, M.; Liang, J.; Lu, X.; Niu, S.; Ahlström, A.; Hararuk, O.; Hastings, A.; Hoffman, F. M.; Medlyn, B. E.; Rasmussen, M.; Smith, M. J.; Todd-Brown, K. E.; Wang, Y.

    2015-12-01

    Terrestrial ecosystems have been estimated to absorb roughly 30% of anthropogenic CO2 emissions. Past studies have identified myriad drivers of terrestrial carbon storage changes, such as fire, climate change, and land use changes. Those drivers influence the carbon storage change via diverse mechanisms, which have not been unified into a general theory so as to identify what control the direction and rate of terrestrial carbon storage dynamics. Here we propose a theoretical framework to quantitatively determine the response of terrestrial carbon storage to different exogenous drivers. With a combination of conceptual reasoning, mathematical analysis, and numeric experiments, we demonstrated that the maximal capacity of an ecosystem to store carbon is time-dependent and equals carbon input (i.e., net primary production, NPP) multiplying by residence time. The capacity is a moving target toward which carbon storage approaches (i.e., the direction of carbon storage change) but usually does not attain. The difference between the capacity and the carbon storage at a given time t is the unrealized carbon storage potential. The rate of the storage change is proportional to the magnitude of the unrealized potential. We also demonstrated that a parameter space of NPP, residence time, and carbon storage potential can well characterize carbon storage dynamics quantified at six sites ranging from tropical forests to tundra and simulated by two versions (carbon-only and coupled carbon-nitrogen) of the Australian Community Atmosphere-Biosphere Land Ecosystem (CABLE) Model under three climate change scenarios (CO2 rising only, climate warming only, and RCP8.5). Overall this study reveals the unified mechanism unerlying terrestrial carbon storage dynamics to guide transient traceability analysis of global land models and synthesis of empirical studies.

  19. Chinas carbon-intensity target: climate actors and policy developments

    Energy Technology Data Exchange (ETDEWEB)

    Stensdal, Iselin

    2012-11-01

    China has become the largest GHG emitting country, and announced in 2009 its first policy objective measured in carbon emissions. The carbon-intensity target is to reduce the carbon intensity by 40-45 % by 2020 compared to 200 levels. Since then there has been further policy developments in order to attain the reduction carbon intensity and steer China towards a low-carbon development. The 12th 5-year plan (2011-2015) is strong on incentives for reducing China's carbon intensity such as energy conservation measures and the establishment of new market-based mechanisms. While the central government forms the policies, the implementation is dependent on a range of actors. In addition to the climate change bureaucracy, the positive forces and actors on GHG mitigation is presented. All in all, there are promising developments in China for the years to come.(auth)

  20. Photopromoted carbonylation of olefins with carbon dioxide and labelling studies with 13CO2 and 13CH3OH

    Institute of Scientific and Technical Information of China (English)

    YIN Jingmei; GAO Dabin; HU Jiehan; ZHOU Guangyun; JIA Yingping; WANG Xiangsheng

    2003-01-01

    Photopromoted carbonylation of olefins with carbon dioxide can be completed in ambient conditions (room temperatures and atmospheric pressure) by Co(OAc)2 catalysis. It was found that in carbonyl carbons of methyl ester of aliphatic acid 50% is from CO2 and the other 50% from CH3OH by labelling experimental with 13CO2 and 13CH3OH.

  1. Synthesis of colchicine and isocolchicine labelled with carbon-11 or carbon-13

    Energy Technology Data Exchange (ETDEWEB)

    Kothari, P.J.; Finn, R.D.; Larson, S.M. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    1995-06-01

    The syntheses of isotopically labelled (-)-10-[{sup 11}C/{sup 13}C]-colchicine and (-)-9-[{sup 11}C/{sup 13}C]-isocolchicine have been achieved from the reaction of (-)desmethylcolchicine with [{sup 11}C/{sup 13}C]-iodomethane. The radiolabelled compounds, (-)-10-[{sup 11}C]-colchicine ({sup 11}C-n-colchicine) and (-)-9-[{sup 11}C]-isocolchicine ({sup 11}C-i-colchicine), were isolated by reversed phase HPLC. The total synthesis time was approximately 60 minutes for both radiolabelled compounds with an average specific activity of 240 mCi/{mu}mol calculated to EOB. Utilizing a similar synthetic strategy, we also reported the synthesis of milligram quantities of the carbon-13 enriched compounds and the magnetic resonance signal assignment for (-)-9-[{sup 13}C] isocolchicine. (Author).

  2. Multiple domains of ADAMTS13 are targeted by autoantibodies against ADAMTS13 in patients with acquired idiopathic thrombotic thrombocytopenic purpura

    Science.gov (United States)

    Zheng, X. Long; Wu, Haifeng M.; Shang, Dezhi; Falls, Erica; Skipwith, Christopher G.; Cataland, Spero R.; Bennett, Charles L.; Kwaan, Hau C.

    2010-01-01

    Background Type G immunoglobulins against ADAMTS13 are the primary cause of acquired (idiopathic) thrombotic thrombocytopenic purpura. However, the domains of ADAMTS13 which the type G anti-ADAMT13 immunoglobulins target have not been investigated in a large cohort of patients with thrombotic thrombocytopenic purpura. Design and Methods Sixty-seven patients with acquired idiopathic thrombotic thrombocytopenic purpura were prospectively collected from three major U.S. centers. An enzyme-linked immunosorbent assay determined plasma concentrations of anti-ADAMTS13 type G immunoglobulins, whereas immunoprecipitation plus western blotting determined the binding domains of these type G immunoglobulins. Results Plasma anti-ADAMTS13 type G immunoglobulins from 67 patients all bound full-length ADAMTS13 and a variant truncated after the eighth TSP1 repeat (delCUB). Approximately 97% (65/67) of patients harbored type G immunoglobulins targeted against a variant truncated after the spacer domain (MDTCS). However, only 12% of patients’ samples reacted with a variant lacking the Cys-rich and spacer domains (MDT). In addition, approximately 37%, 31%, and 46% of patients’ type G immunoglobulins interacted with the ADAMTS13 fragment containing TSP1 2-8 repeats (T2-8), CUB domains, and TSP1 5-8 repeats plus CUB domains (T5-8CUB), respectively. The presence of type G immunoglobulins targeted against the T2-8 and/or CUB domains was inversely correlated with the patients’ platelet counts on admission. Conclusions This multicenter study further demonstrated that the multiple domains of ADAMTS13, particularly the Cys-rich and spacer domains, are frequently targeted by anti-ADAMTS13 type G immunoglobulins in patients with acquired (idiopathic) thrombotic thrombocytopenic purpura. Our data shed more light on the pathogenesis of acquired thrombotic thrombocytopenic purpura and provide further rationales for adjunctive immunotherapy. PMID:20378566

  3. High dynamic orientation of protons, deuterons and carbon-13 nuclei

    International Nuclear Information System (INIS)

    The behaviour of hydrogen, deuterium, and carbon-13 nuclear spin systems have been studied in partially deuterated diols, doped with paramagnetic Crsup(V) complexes, between 0.1 and 0.5 K. Experimental evidence is given that the dynamic polarization in such samples comes from a cooling of the electron spin-spin interaction reservoir by off-resonance microwave irradiation; a strong thermal coupling between this reservoir and the nuclear Zeeman reservoirs cools these too, thus changing the polarizations. In a 25 kG magnetic field at a lattice temperature of 0.37 K we reached a common spin temperature for the nuclear Zeeman reservoirs of 1.1 mK in 1,2-propanediol-D6, which corresponds to a proton polarization of 98%, a deuteron polarization of 44%, and a carbon-13 polarization of 52%. A new way of dynamic orientation of the deuteron spin system was found. It allows one to vary the deuteron tensor polarization or alignment independently of its vector polarization. This can be done by slightly off-resonance RF irradiation of the polarized proton system, which cools the proton spin-spin interaction reservoir. It appeared that at the same time the RF field provides a thermal contract between this reservoir and the deuteron quadrupole interaction reservoir, which caused the observed alignment. Values around 60% were reached for some parts of the deuteron spin system, corresponding to a deuteron quadrupole spin temperature of 7 uK. The dependence of the alignment on RF frequency and initial proton polarization as well as thermal mixing rates are in good agreement with quantitative estimates from spin temperature theory. (author)

  4. Structural properties of carbon nanotubes derived from 13C NMR

    KAUST Repository

    Abou-Hamad, E.

    2011-10-10

    We present a detailed experimental and theoretical study on how structural properties of carbon nanotubes can be derived from 13C NMR investigations. Magic angle spinning solid state NMR experiments have been performed on single- and multiwalled carbon nanotubes with diameters in the range from 0.7 to 100 nm and with number of walls from 1 to 90. We provide models on how diameter and the number of nanotube walls influence NMR linewidth and line position. Both models are supported by theoretical calculations. Increasing the diameter D, from the smallest investigated nanotube, which in our study corresponds to the inner nanotube of a double-walled tube to the largest studied diameter, corresponding to large multiwalled nanotubes, leads to a 23.5 ppm diamagnetic shift of the isotropic NMR line position δ. We show that the isotropic line follows the relation δ = 18.3/D + 102.5 ppm, where D is the diameter of the tube and NMR line position δ is relative to tetramethylsilane. The relation asymptotically tends to approach the line position expected in graphene. A characteristic broadening of the line shape is observed with the increasing number of walls. This feature can be rationalized by an isotropic shift distribution originating from different diamagnetic shielding of the encapsulated nanotubes together with a heterogeneity of the samples. Based on our results, NMR is shown to be a nondestructive spectroscopic method that can be used as a complementary method to, for example, transmission electron microscopy to obtain structural information for carbon nanotubes, especially bulk samples.

  5. Bremsstrahlung in carbon thick targets by proton incidence

    International Nuclear Information System (INIS)

    The subtraction of the continuum from an X-ray spectrum emitted by proton bombardment is usually carried out by means of a mathematical fitting. The purpose of the present work is to develop an analytical function to model the continuous spectrum generated in a PIXE experiment for different incident beam energies in carbon thick targets. With this purpose, PIXE spectra of a carbon bulk sample were measured in an ion accelerator. The proton beam energies were varied between 0.7 MeV and 2 MeV and the X-rays generated were collected by an energy dispersive spectrometer. The spectra analysis was performed taking into account the main effects underlying the production of the continuous spectrum. Nevertheless, for the cases considered here, it was found that the atomic bremsstrahlung is the most important and other contributions were neglected. The experimental spectra from carbon thick targets were corrected by self-absorption and detector efficiency. The results show that the spectral shape corresponding to thick targets corrected by these effects is similar to the functional behavior presented by thin targets

  6. Water, hydrogen, deuterium, carbon, carbon-13, and oxygen-18 content of selected lunar material

    Science.gov (United States)

    Friedman, I.; O'Neil, J.R.; Adami, L.H.; Gleason, J.D.; Hardcastle, K.

    1970-01-01

    The water content of the breccia is 150 to 455 ppm, with a ??D from -580 to -870 per mil. Hydrogen gas content is 40 to 53 ppm with a ??D of -830 to -970 per mil. The CO2 is 290 to 418 ppm with S 13C = + 2.3 to + 5.1 per mil and ??18O = 14.2 to 19.1 per mil. Non-CO2 carbon is 22 to 100 ppm, ??18C = -6.4 to -23.2 per mil. Lunar dust is 810 ppm H2O (D = 80 ppm) and 188 ppm total carbon (??13C = -17.6 per mil). The 18O analyses of whole rocks range from 5.8 to 6.2 per mil. The temperature of crystallization of type B rocks is 1100?? to 1300??C, based on the oxygen isotope fractionation between coexisting plagioclase and ilmenite.

  7. Development of additive [{sup 11}C]CO{sub 2} target system in the KOTRON-13 cyclotron and its application for [{sup 11}C]radiopharmaceutical production

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Byung Seok; Lee, Hong Jin [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707 (Korea, Republic of); Lee, Won Kyung [Technical Support Team, Duchembio, Seoul 121-844 (Korea, Republic of); Hur, Min Goo; Yang, Seung Dae [Radiation Instrumentation Research Division, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Lee, Byung Chul, E-mail: leebc2001@gmail.com [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707 (Korea, Republic of); Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 443-270 (Korea, Republic of); Kim, Sang Eun [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam 463-707 (Korea, Republic of); Center for Nanomolecular Imaging and Innovative Drug Development, Advanced Institutes of Convergence Technology, Suwon 443-270 (Korea, Republic of); Smart Humanity Convergence Center, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 443-270 (Korea, Republic of)

    2015-08-01

    The KOTRON-13 cyclotron, which was developed in South Korea for the production of medical radioisotopes, has the structural limitation of only one beam-output port, restricting the production of the carbon-11 isotope. In the present study, we investigate the design of a switchable target system and develop an effective carbon-11 target in the KOTRON-13 cyclotron, for combination with the fluorine-18 target. The target system was designed by introducing a sliding-type element between the fluorine-18 and carbon-11 targets, a tailor-made C-11 target and its cooling system. For the efficient production of [{sup 11}C]CO{sub 2}, the desirable target shape and internal volume were determined by a Stopping and Range of Ions in Matter (SRIM) simulation program, and the target grid was modified to resist the cavity pressure during beam irradiation. We evaluated the [{sup 11}C]CO{sub 2} production while varying the material and thickness of the target foil, oxygen content of the nitrogen gas, and target loading pressure. Using sliding-type equipment including an additional gate valve and a high vacuum in a beam line, the bi-directional conversion between the fluorine-18 and carbon-11 targets was efficient regarding the accurate beam irradiation on both targets. The optimal [{sup 11}C]CO{sub 2} production for 30 min irradiation at 60 μA (86.6 ± 1.7 GBq in the target at EOB) was observed at a thickness of 19 μm with HAVAR® material as a target foil and a target loading pressure of 24 bar with nitrogen plus 300 ppb of oxygen gas. Additionally, the coolant cavity system in the target grid and target chamber is useful to remove the heat transferred to the target body by the internal convection of water and thereby ensure the stability of the [{sup 11}C]CO{sub 2} production under a high beam current. In the application of C-11 labeled radiopharmaceuticals such as [{sup 11}C]PIB, [{sup 11}C]DASB, [{sup 11}C]PBR28, [{sup 11}C]Methionine and [{sup 11}C]Clozapine, the radiochemical

  8. Development of additive [11C]CO2 target system in the KOTRON-13 cyclotron and its application for [11C]radiopharmaceutical production

    International Nuclear Information System (INIS)

    The KOTRON-13 cyclotron, which was developed in South Korea for the production of medical radioisotopes, has the structural limitation of only one beam-output port, restricting the production of the carbon-11 isotope. In the present study, we investigate the design of a switchable target system and develop an effective carbon-11 target in the KOTRON-13 cyclotron, for combination with the fluorine-18 target. The target system was designed by introducing a sliding-type element between the fluorine-18 and carbon-11 targets, a tailor-made C-11 target and its cooling system. For the efficient production of [11C]CO2, the desirable target shape and internal volume were determined by a Stopping and Range of Ions in Matter (SRIM) simulation program, and the target grid was modified to resist the cavity pressure during beam irradiation. We evaluated the [11C]CO2 production while varying the material and thickness of the target foil, oxygen content of the nitrogen gas, and target loading pressure. Using sliding-type equipment including an additional gate valve and a high vacuum in a beam line, the bi-directional conversion between the fluorine-18 and carbon-11 targets was efficient regarding the accurate beam irradiation on both targets. The optimal [11C]CO2 production for 30 min irradiation at 60 μA (86.6 ± 1.7 GBq in the target at EOB) was observed at a thickness of 19 μm with HAVAR® material as a target foil and a target loading pressure of 24 bar with nitrogen plus 300 ppb of oxygen gas. Additionally, the coolant cavity system in the target grid and target chamber is useful to remove the heat transferred to the target body by the internal convection of water and thereby ensure the stability of the [11C]CO2 production under a high beam current. In the application of C-11 labeled radiopharmaceuticals such as [11C]PIB, [11C]DASB, [11C]PBR28, [11C]Methionine and [11C]Clozapine, the radiochemical yields were shown to be 25–38% (decay corrected) with over 166 GBq/μmol of

  9. Phenotyping hepatocellular metabolism using uniformly labeled carbon-13 molecular probes and LC-HRMS stable isotope tracing.

    Science.gov (United States)

    Meissen, John K; Pirman, David A; Wan, Min; Miller, Emily; Jatkar, Aditi; Miller, Russell; Steenwyk, Rick C; Blatnik, Matthew

    2016-09-01

    Metabolite stable isotope tracing is a powerful bioanalytical strategy that has the potential to unravel phenotypic markers of early pharmaceutical efficacy by monitoring enzymatic incorporation of carbon-13 atoms into targeted pathways over time. The practice of probing biological systems with carbon-13 labeled molecules using broad MS-based screens has been utilized for many years in academic laboratories but has had limited application in the pharmaceutical R&D environment. The goal of this work was to establish a LCMS analytical workflow that was capable of monitoring carbon-13 isotope changes in glycolysis, the TCA and urea cycles, and non-essential amino acid metabolism. This work applies a standardized protein precipitation with 80% cold methanol and two distinct reverse-phase ion-pair liquid chromatography methods coupled to either a positive- or negative-ion mode high-resolution accurate mass spectrometry screening method. The data herein combines thousands of single-point peak integrations into a novel metabolite network map as a visualization aid to probe and monitor stable isotope incorporation in murine hepatocytes using uniformly labeled (13)C6 glucose, (13)C3 lactate, and (13)C5 glutamine. This work also demonstrates that nitrogen metabolism may have a large influence on the TCA cycle and gluconeogenic carbon fluxes in hepatocyte cell culture. PMID:27343766

  10. Study of $^{13}$Be through isobaric analog resonances in the Maya active target

    CERN Multimedia

    Riisager, K; Orr, N A; Jonson, B N G; Raabe, R; Fynbo, H O U; Nilsson, T

    We propose to perform an experiment with a $^{12}$Be beam and the Maya active target. We intend to study the ground state of $^{13}$Be through the population of its isobaric analog resonance in $^{13}$B. The resonance will be identified detecting its proton- and neutron-decay channels.

  11. Aminopeptidase N/CD13 targeting fluorescent probes: synthesis and application to tumor cell imaging.

    Science.gov (United States)

    Zhang, Zhouen; Harada, Hiroshi; Tanabe, Kazuhito; Hatta, Hiroshi; Hiraoka, Masahiro; Nishimoto, Sei-ichi

    2005-11-01

    A family of fluorescein-peptide conjugates (CNP1-3) for aminopeptidase N (APN/CD13) targeting fluorescent probes were designed and synthesized. Among the three conjugates, CNP1 bearing tumor-homing cyclic peptide CNGRC, could selectively label APN/CD13 over-expressing on the surface of tumor cells of HT-1080, as identified by means of fluorescent microscopic cell imaging. CNP1 was shown to be a promising fluorescent probe applicable to tumor-targeting molecular imaging. PMID:15885853

  12. Carbon-13 nuclear magnetic resonance as a probe of side chain orientation and mobility in carboxymethylated human carbonic anhydrase B

    NARCIS (Netherlands)

    Schoot Uiterkamp, Antonius J.M.; Armitage, Ian M.; Prestegard, James H.; Slomski, John; Coleman, Joseph E.

    1978-01-01

    13C NMR spectra of [1-13C]- and [2-13C]carboxymethyl His-200 human carbonic anhydrase B have been obtained as a function of pH and in the presence and absence of the active site Zn(II) or Cd(II) ion. Chemical shifts of the 1-13C show that the carboxyl is sensitive to two ionization processes, with a

  13. Studying biosphere-atmosphere exchange of CO2 through Carbon-13 stable isotopes

    NARCIS (Netherlands)

    Velde, van der I.R.

    2015-01-01

    Summary Thesis ‘Studying biosphere-atmosphere exchange of CO2 through carbon-13 stable isotopes’ Ivar van der Velde Making predictions of future climate is difficult, mainly due to large uncertainties in the carbon cycle. The rate at which carbon is stored in the oceans and terrestrial b

  14. Proposal to realize a cost breakthrough in carbon-13 production by photochemical separation

    International Nuclear Information System (INIS)

    A cost breakthrough can now be made in photochemical production of the rare stable isotope carbon-13. This cost breakthrough is achieved by CO2 laser infrared multiple-photon dissociation of any of several halocarbons (Freon derivatives) such as CF3Cl, CF3Br, or CF2Cl2. The single-step carbon-13 enrichment factor for this process is approximately 50, yielding 30% pure C-13 in one step, or up to 97% pure C-13 in two steps. A three-fold carbon-13 cost reduction to below $20/gram is expected to be achieved in a small laboratory-scale demonstration facility capable of producing 4 to 8 kg/year of carbon-13, using presently available pulsed CO2 TEA lasers at an average power level of 50 watts. Personnel costs dominate the attainable C-13 production costs in a small photochemical enrichment facility. A price reduction to $2/gm carbon-13 is feasible at carbon-13 production levels of 100 to 1000 kg/year, dominated by the Freon raw material costs

  15. Identification of excitonic phonon sideband by photoluminescence spectroscopy of single-walled carbon-13 nanotubes

    OpenAIRE

    Miyauchi, Yuhei; Maruyama, Shigeo

    2005-01-01

    We have studied photoluminescence (PL) and resonant Raman scatterings of single-walled carbon nanotubes (SWNTs) consisting of carbon-13 (SW13CNTs) synthesized from a small amount of isotopically modified ethanol. There was almost no change in the Raman spectra shape for SW13CNTs except for a downshift of the Raman shift frequency by the square-root of the mass ratio 12/13. By comparing photoluminescence excitation (PLE) spectra of SW13CNTs and normal SWNTs, the excitonic phonon sideband due t...

  16. Measurement of pion double charge exchange on carbon-13, carbon-14, magnesium-26, and iron-56

    Energy Technology Data Exchange (ETDEWEB)

    Seidl, P.A.

    1985-02-01

    Cross sections for the /sup 13,14/C,/sup 26/Mg,/sup 56/Fe(..pi../sup +/,..pi../sup -/)/sup 13,14/O,/sup 26/Si,/sup 56/Ni reactions were measured with the Energetic Pion Channel and Spectrometer at the Clinton P. Anderson Meson Physics Facility for 120 less than or equal to T/sub ..pi../ less than or equal to 292 MeV and 0 less than or equal to theta less than or equal to 50. The double isobaric analog states (DIAS) are of primary interest. In addition, cross sections for transitions to /sup 14/O(0/sup +/, 5.92 MeV), /sup 14/O(2/sup +/, 7.77 MeV), /sup 56/Ni(gs), /sup 13/O(gs), and /sup 13/O(4.21 MeV) are presented. The /sup 13/O(4.21 MeV) state is postulated to have J/sup ..pi../ = 1/2/sup -/. The data are compared to previously measured double-charge-exchange cross sections on other nuclei, and the systematics of double charge exchange on T greater than or equal to 1 target nuclei leading to the DIAS are studied. Near the ..delta../sub 33/ resonance, cross sections for the DIAS transitions are in disagreement with calculations in which the reaction is treated as sequential charge exchange through the free pion-nucleon amplitude, while for T/sub ..pi../ > 200 MeV the anomalous features of the 164 MeV data are not apparent. This is evidence for significant higher order contributions to the double-charge-exchange amplitude near the reasonable energy. Two theoretical approaches that include two nucleon processes are applied to the DIAS data. 64 references.

  17. Staphylococcus aureus Peptidoglycan Tertiary Structure from Carbon-13 Spin Diffusion

    OpenAIRE

    Sharif, Shasad; Singh, Manmilan; Kim, Sung Joon; Schaefer,Jacob

    2009-01-01

    The cell-wall peptidoglycan of Staphylococcus aureus is a heterogeneous, highly cross-linked polymer of unknown tertiary structure. We have partially characterized this structure by measuring spin diffusion from 13C labels in pentaglycyl cross-linking segments to natural-abundance 13C in the surrounding intact cell walls. The measurements were performed using a version of centerband-only detection of exchange (CODEX). The cell walls were isolated from S. aureus grown in media containing [1-13...

  18. M13-templated magnetic nanoparticles for targeted in vivo imaging of prostate cancer

    Science.gov (United States)

    Ghosh, Debadyuti; Lee, Youjin; Thomas, Stephanie; Kohli, Aditya G.; Yun, Dong Soo; Belcher, Angela M.; Kelly, Kimberly A.

    2012-10-01

    Molecular imaging allows clinicians to visualize the progression of tumours and obtain relevant information for patient diagnosis and treatment. Owing to their intrinsic optical, electrical and magnetic properties, nanoparticles are promising contrast agents for imaging dynamic molecular and cellular processes such as protein-protein interactions, enzyme activity or gene expression. Until now, nanoparticles have been engineered with targeting ligands such as antibodies and peptides to improve tumour specificity and uptake. However, excessive loading of ligands can reduce the targeting capabilities of the ligand and reduce the ability of the nanoparticle to bind to a finite number of receptors on cells. Increasing the number of nanoparticles delivered to cells by each targeting molecule would lead to higher signal-to-noise ratios and would improve image contrast. Here, we show that M13 filamentous bacteriophage can be used as a scaffold to display targeting ligands and multiple nanoparticles for magnetic resonance imaging of cancer cells and tumours in mice. Monodisperse iron oxide magnetic nanoparticles assemble along the M13 coat, and its distal end is engineered to display a peptide that targets SPARC glycoprotein, which is overexpressed in various cancers. Compared with nanoparticles that are directly functionalized with targeting peptides, our approach improves contrast because each SPARC-targeting molecule delivers a large number of nanoparticles into the cells. Moreover, the targeting ligand and nanoparticles could be easily exchanged for others, making this platform attractive for in vivo high-throughput screening and molecular detection.

  19. Carbon-13 magnetic resonance of hydrocarbons. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Grant, D.M.; Pugmire, R.J.

    1979-01-01

    Several tetralins, tetrahydrophenanthrenes, and dihydroanthracenes were synthesized, /sup 13/C spin-lattice relaxation measurements were carried out on aromatic and hydroaromatic compounds. /sup 13/C chemical shift studies were also conducted on methylated 1,2,3,4-tetrahydronaphthalenes, 1,2,3,4-tetrahydrophenanthrenes, and 9,10-dihydroanthracenes. (DLC)

  20. Drought indicated in carbon-13/carbon-12 ratios of Southwestern tree rings

    International Nuclear Information System (INIS)

    Stomatal closure during periods of moisture deficiency should theoretically lead to elevated 13C/12C ratios as reduction of available CO2 leads to diminished photosynthetic discrimination against 13C in favor of 12C. Stable-carbon isotope ratio chronologies developed from 5-yr tree-ring groups at 17 sites in six southwestern states were tested for a drought relationship by first fitting a spline curve to each chronology to remove the long-term trend and calculating indices as the ratio of actual to spline curve value. The time series of “Del Indices” so developed are significantly correlated with 5-yr mean Palmer Hydrological Drought Indices (post-1930 period) and reconstructed July Palmer Drought Severity Indices from respective areas. Overall, in the period since 1790, the driest pentads were 1900–04 and 1960–64, whereas the wettest were 1980–84 and 1915–19. Maps of drought represented for two pentads seem to be reasonable representations, although spatial correlations of Del Indices with PHDI were generally not significant. These Del Index drought reconstructions may provide a useful measure of past physiological response to drought (stomatal closure), although the present cost of analysis would prevent this from being a routine method. (author)

  1. Progress on polarized target materials with pure carbon background

    International Nuclear Information System (INIS)

    A previous note reviewed methods for the paramagnetic doping of materials for spin-polarized solid targets and some of the history of attempts to apply those methods to hydrocarbons. Since the earlier work on hydrocarbons had yielded, at best, rather mediocre results, that note also speculated on some ways to extend and, possibly, to improve upon the earlier work. The sharpest focus was on the light (number of carbons less than six) alkanes, since these are the hydrocarbons that have the highest hydrogen contents (approx-gt 17wt %) and therefore require the least degree of polarization to be interesting. This present note summarizes the subsequent work done, to date, exploring some of the issues related to the chemical doping method. The main areas of progress have been in the literature search, experimental results on glass formation by alkanes, and a polarizing test of a ''prototype'' hydrocarbon

  2. Legionella pneumophila Carbonic Anhydrases: Underexplored Antibacterial Drug Targets.

    Science.gov (United States)

    Supuran, Claudiu T

    2016-01-01

    Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes which catalyze the hydration of carbon dioxide to bicarbonate and protons. Many pathogenic bacteria encode such enzymes belonging to the α-, β-, and/or γ-CA families. In the last decade, enzymes from some of these pathogens, including Legionella pneumophila, have been cloned and characterized in detail. These enzymes were shown to be efficient catalysts for CO₂ hydration, with kcat values in the range of (3.4-8.3) × 10⁵ s(-1) and kcat/KM values of (4.7-8.5) × 10⁷ M(-1)·s(-1). In vitro inhibition studies with various classes of inhibitors, such as anions, sulfonamides and sulfamates, were also reported for the two β-CAs from this pathogen, LpCA1 and LpCA2. Inorganic anions were millimolar inhibitors, whereas diethyldithiocarbamate, sulfamate, sulfamide, phenylboronic acid, and phenylarsonic acid were micromolar ones. The best LpCA1 inhibitors were aminobenzolamide and structurally similar sulfonylated aromatic sulfonamides, as well as acetazolamide and ethoxzolamide (KIs in the range of 40.3-90.5 nM). The best LpCA2 inhibitors belonged to the same class of sulfonylated sulfonamides, together with acetazolamide, methazolamide, and dichlorophenamide (KIs in the range of 25.2-88.5 nM). Considering such preliminary results, the two bacterial CAs from this pathogen represent promising yet underexplored targets for obtaining antibacterials devoid of the resistance problems common to most of the clinically used antibiotics, but further studies are needed to validate them in vivo as drug targets. PMID:27322334

  3. Legionella pneumophila Carbonic Anhydrases: Underexplored Antibacterial Drug Targets

    Directory of Open Access Journals (Sweden)

    Claudiu T. Supuran

    2016-06-01

    Full Text Available Carbonic anhydrases (CAs, EC 4.2.1.1 are metalloenzymes which catalyze the hydration of carbon dioxide to bicarbonate and protons. Many pathogenic bacteria encode such enzymes belonging to the α-, β-, and/or γ-CA families. In the last decade, enzymes from some of these pathogens, including Legionella pneumophila, have been cloned and characterized in detail. These enzymes were shown to be efficient catalysts for CO2 hydration, with kcat values in the range of (3.4–8.3 × 105 s−1 and kcat/KM values of (4.7–8.5 × 107 M−1·s−1. In vitro inhibition studies with various classes of inhibitors, such as anions, sulfonamides and sulfamates, were also reported for the two β-CAs from this pathogen, LpCA1 and LpCA2. Inorganic anions were millimolar inhibitors, whereas diethyldithiocarbamate, sulfamate, sulfamide, phenylboronic acid, and phenylarsonic acid were micromolar ones. The best LpCA1 inhibitors were aminobenzolamide and structurally similar sulfonylated aromatic sulfonamides, as well as acetazolamide and ethoxzolamide (KIs in the range of 40.3–90.5 nM. The best LpCA2 inhibitors belonged to the same class of sulfonylated sulfonamides, together with acetazolamide, methazolamide, and dichlorophenamide (KIs in the range of 25.2–88.5 nM. Considering such preliminary results, the two bacterial CAs from this pathogen represent promising yet underexplored targets for obtaining antibacterials devoid of the resistance problems common to most of the clinically used antibiotics, but further studies are needed to validate them in vivo as drug targets.

  4. 13 CFR 124.509 - What are non-8(a) business activity targets?

    Science.gov (United States)

    2010-01-01

    ... reasonable marketing strategy, to attain the targeted dollar levels of non-8(a) revenue established in its... achieved the required level of non-8(a) business at its nine-month review, SBA will measure 8(a) support by... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false What are non-8(a)...

  5. Fusion cross sections of carbon isotopes obtained with an ionization chamber in active target mode

    International Nuclear Information System (INIS)

    Carbon fusion has provided questions to both physicists and astronomers for at least the last 50 years. From fundamental nuclear structure to recent discoveries in stellar phenomena there are still open topics. Fusion in the 12C + 12C system show oscillations that are not present in neighboring systems and are yet not completely understood. Unexplained behavior in the threshold between 1p and 2s1d shells is seen as fusion cross sections show significant changes in systems which differ by only a nucleon. A new type of stellar explosions, called super bursts, in X-ray binaries were recently observed and are thought to require fusion of radioactive carbon isotopes for an explanation, opening new paths for stellar nucleosynthesis. These are a few interesting examples that motivated the development of a new measurement technique, which comprises a Multi Sampling Ionization Chamber (Music) operated in active target mode, with methane gas (C H4) as both counting gas and reaction target. This offers a high efficiency detection method where excitation functions can be sampled, using a single beam energy, in a range determined by the ionization gas pressure. This is a great advantage since it drastically reduces the measurement time and the data are automatically normalized. The high efficiency of the detector makes it ideal for experiments where the reaction cross section and/or the beam intensity are low, i.e. for processes involving radioactive nuclei. Using the Music, fusion cross sections in systems with carbon isotopes of mass numbers A = 10, 12, 13, 14, 15 impinging on a carbon-12 target have been measured. Beam energies of about 3 MeV/A were used for obtaining fusion excitation functions in the center of mass energy range between 10 and 20 MeV. In this contribution, the operation principle of the Music is discussed. Then, the experimental excitation functions are presented and compared with previous data (3when available) and different theoretical models

  6. Natural abundance measurements of 13C indicate increased deep soil carbon mineralization after forest disturbance

    Science.gov (United States)

    Diochon, Amanda; Kellman, Lisa

    2008-07-01

    Northern forest soils represent globally important stores of carbon (C), yet there is no consensus about how they are altered by the widespread practice of harvesting that dominates many forested landscapes. Here we present the first study to systematically investigate the utility of δ 13C and C content depth profiles to infer temporal changes in belowground carbon cycling processes following disturbance in a pure C3 ecosystem. We document carbon concentration and δ 13C depth profile enrichment trends consistent with a kinetic fractionation arising from soil organic carbon (SOC) humification across a northern forest chronosequence (1, 15, 45, 80 and 125+ yrs). Reduced soil C storage that coincided with observed soil profile δ 13C-enrichment patterns which intensified following clearcut harvesting, pointed to losses of SOC in the deeper (>20 cm) mineral soil. This study suggests the δ 13C approach may assist in identifying mechanisms responsible for soil C storage changes in disturbed C3 forest ecosystems.

  7. Spectrally edited 2D 13Csbnd 13C NMR spectra without diagonal ridge for characterizing 13C-enriched low-temperature carbon materials

    Science.gov (United States)

    Johnson, Robert L.; Anderson, Jason M.; Shanks, Brent H.; Fang, Xiaowen; Hong, Mei; Schmidt-Rohr, Klaus

    2013-09-01

    Two robust combinations of spectral editing techniques with 2D 13Csbnd 13C NMR have been developed for characterizing the aromatic components of 13C-enriched low-temperature carbon materials. One method (exchange with protonated and nonprotonated spectral editing, EXPANSE) selects cross peaks of protonated and nearby nonprotonated carbons, while the other technique, dipolar-dephased double-quantum/single-quantum (DQ/SQ) NMR, selects signals of bonded nonprotonated carbons. Both spectra are free of a diagonal ridge, which has many advantages: Cross peaks on the diagonal or of small intensity can be detected, and residual spinning sidebands or truncation artifacts associated with the diagonal ridge are avoided. In the DQ/SQ experiment, dipolar dephasing of the double-quantum coherence removes protonated-carbon signals; this approach also eliminates the need for high-power proton decoupling. The initial magnetization is generated with minimal fluctuation by combining direct polarization, cross polarization, and equilibration by 13C spin diffusion. The dipolar dephased DQ/SQ spectrum shows signals from all linkages between aromatic rings, including a distinctive peak from polycondensed aromatics. In EXPANSE NMR, signals of protonated carbons are selected in the first spectral dimension by short cross polarization combined with dipolar dephasing difference. This removes ambiguities of peak assignment to overlapping signals of nonprotonated and protonated aromatic carbons, e.g. near 125 ppm. Spin diffusion is enhanced by dipolar-assisted rotational resonance. Before detection, Csbnd H dipolar dephasing by gated decoupling is applied, which selects signals of nonprotonated carbons. Thus, only cross peaks due to magnetization originating from protonated C and ending on nearby nonprotonated C are retained. Combined with the chemical shifts deduced from the cross-peak position, this double spectral editing defines the bonding environment of aromatic, COO, and Cdbnd O carbons

  8. Imaging and treating tumor vasculature with targeted radiolabeled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Alessandro Ruggiero

    2010-09-01

    Full Text Available Alessandro Ruggiero1*, Carlos H Villa1*, Jason P Holland1, Shanna R Sprinkle1, Chad May2, Jason S Lewis1, David A Scheinberg1, Michael R McDevitt11Departments of Medicine and Radiology, Pharmacology and Molecular Therapeutics, Memorial Sloan-Kettering Cancer Center, New York, USA; 2ImClone Systems, New York, USA; *Ruggiero and Villa contributed equally to this workAbstract: Single wall carbon nanotube (SWCNT constructs were covalently appended with radiometal-ion chelates (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid [DOTA] or desferrioxamine B [DFO] and the tumor neovascular-targeting antibody E4G10. The E4G10 antibody specifically targeted the monomeric vascular endothelial-cadherin (VE-cad epitope expressed in the tumor angiogenic vessels. The construct specific activity and blood compartment clearance kinetics were significantly improved relative to corresponding antibody-alone constructs. We performed targeted radioimmunotherapy with a SWCNT-([225Ac]DOTA(E4G10 construct directed at the tumor vasculature in a murine xenograft model of human colon adenocarcinoma (LS174T. The specific construct reduced tumor volume and improved median survival relative to controls. We also performed positron emission tomographic (PET radioimmunoimaging of the tumor vessels with a SWCNT-([89Zr]DFO(E4G10 construct in the same murine LS174T xenograft model and compared the results to appropriate controls. Dynamic and longitudinal PET imaging of LS174T tumor-bearing mice demonstrated rapid blood clearance (<1 hour and specific tumor accumulation of the specific construct. Incorporation of the SWCNT scaffold into the construct design permitted us to amplify the specific activity to improve the signal-to-noise ratio without detrimentally impacting the immunoreactivity of the targeting antibody moiety. Furthermore, we were able to exploit the SWCNT pharmacokinetic (PK profile to favorably alter the blood clearance and provide an advantage for rapid

  9. In vivo 13 carbon metabolic imaging at 3T with hyperpolarized 13C-1-pyruvate.

    Science.gov (United States)

    Kohler, S J; Yen, Y; Wolber, J; Chen, A P; Albers, M J; Bok, R; Zhang, V; Tropp, J; Nelson, S; Vigneron, D B; Kurhanewicz, J; Hurd, R E

    2007-07-01

    We present for the first time dynamic spectra and spectroscopic images acquired in normal rats at 3T following the injection of (13)C-1-pyruvate that was hyperpolarized by the dynamic nuclear polarization (DNP) method. Spectroscopic sampling was optimized for signal-to-noise ratio (SNR) and for spectral resolution of (13)C-1-pyruvate and its metabolic products (13)C-1-alanine, (13)C-1-lactate, and (13)C-bicarbonate. Dynamic spectra in rats were collected with a temporal resolution of 3 s from a 90-mm axial slab using a dual (1)H-(13)C quadrature birdcage coil to observe the combined effects of metabolism, flow, and T(1) relaxation. In separate experiments, spectroscopic imaging data were obtained during a 17-s acquisition of a 20-mm axial slice centered on the rat kidney region to provide information on the spatial distribution of the metabolites. Conversion of pyruvate to lactate, alanine, and bicarbonate occurred within a minute of injection. Alanine was observed primarily in skeletal muscle and liver, while pyruvate, lactate, and bicarbonate concentrations were relatively high in the vasculature and kidneys. In contrast to earlier work at 1.5 T, bicarbonate was routinely observed in skeletal muscle as well as the kidney and vasculature. PMID:17659629

  10. Developing high-resolution carbon-13 and silicon-29 MRI of solids in sedimentary rocks

    Science.gov (United States)

    Blum, Robert; Barrett, Sean; Viswanathan, Ravinath; Song, Yi-Qiao

    2014-03-01

    Mapping pore structure and flow properties of sedimentary rock is directly relevant to current challenges in geophysics like carbon sequestration and oil/gas exploration. Such applications require detailed information about both structure and composition of porous rocks. However, existing scanning methods tend to be limited to gathering one or the other type of information. MRI could be used to measure both composition and structure simultaneously, but conventional MRI in such systems, which targets the proton signal of interstitial fluid, is severely limited by signal losses due to magnetic susceptibility inhomogeneity. Our lab has recently made advances in obtaining high spatial resolution (sub-400 μm)3 three-dimensional 31P MRI of bone through use of the quadratic echo line-narrowing sequence (1). In this talk, we describe our current work applying these methods to sedimentary rock, targeting the isotopes 13C and 29Si. We describe the results of characterization of limestone and shale samples, and we discuss our progress with producing MRI of these systems. (1) M. Frey, et al. PNAS 109: 5190 (2012)

  11. Carbon-13 magnetic resonance chemical shift additivity relationships of clinically used furocoumarins and furchromones

    International Nuclear Information System (INIS)

    The natural abundance carbon-13 nuclear magnetic resonance spectra of various clinically used furocoumarins and furochromones have been studied. The assignments of carbon chemical shift values were based on the theory of chemical shift, additivity rules, SFORD spectra and model compounds. (author)

  12. Autotrophic carbon budget in coral tissue: a new 13C-based model of photosynthate translocation.

    Science.gov (United States)

    Tremblay, Pascale; Grover, Renaud; Maguer, Jean François; Legendre, Louis; Ferrier-Pagès, Christine

    2012-04-15

    Corals live in symbiosis with dinoflagellates of the genus Symbiodinum. These dinoflagellates translocate a large part of the photosynthetically fixed carbon to the host, which in turn uses it for its own needs. Assessing the carbon budget in coral tissue is a central question in reef studies that still vexes ecophysiologists. The amount of carbon fixed by the symbiotic association can be determined by measuring the rate of photosynthesis, but the amount of carbon translocated by the symbionts to the host and the fate of this carbon are more difficult to assess. In the present study, we propose a novel approach to calculate the budget of autotrophic carbon in the tissue of scleractinian corals, based on a new model and measurements made with the stable isotope (13)C. Colonies of the scleractinian coral Stylophora pistillata were incubated in H(13)CO (-)(3)-enriched seawater, after which the fate of (13)C was followed in the symbionts, the coral tissue and the released particulate organic carbon (i.e. mucus). Results obtained showed that after 15 min, ca. 60% of the carbon fixed was already translocated to the host, and after 48 h, this value reached 78%. However, ca. 48% of the photosynthetically fixed carbon was respired by the symbiotic association, and 28% was released as dissolved organic carbon. This is different from other coral species, where coral tissue after 48 h. Results show that our (13)C-based model could successfully trace the carbon flow from the symbionts to the host, and the photosynthetically acquired carbon lost from the symbiotic association. PMID:22442377

  13. Enhanced biosynthetically directed fractional carbon-13 enrichment of proteins for backbone NMR assignments.

    Science.gov (United States)

    Wenrich, Broc R; Sonstrom, Reilly E; Gupta, Riju A; Rovnyak, David

    2015-11-01

    Routes to carbon-13 enrichment of bacterially expressed proteins include achieving uniform or positionally selective (e.g. ILV-Me, or (13)C', etc.) enrichment. We consider the potential for biosynthetically directed fractional enrichment (e.g. carbon-13 incorporation in the protein less than 100%) for performing routine n-(D)dimensional NMR spectroscopy of proteins. First, we demonstrate an approach to fractional isotope addition where the initial growth media containing natural abundance glucose is replenished at induction with a small amount (e.g. 10%(w/w)u-(13)C-glucose) of enriched nutrient. The approach considered here is to add 10% (e.g. 200mg for a 2g/L culture) u-(13)C-glucose at the induction time (OD600=0.8), resulting in a protein with enhanced (13)C incorporation that gives almost the same NMR signal levels as an exact 20% (13)C sample. Second, whereas fractional enrichment is used for obtaining stereospecific methyl assignments, we find that (13)C incorporation levels no greater than 20%(w/w) yield (13)C and (13)C-(13)C spin pair incorporation sufficient to conduct typical 3D-bioNMR backbone experiments on moderate instrumentation (600 MHz, RT probe). Typical 3D-bioNMR experiments of a fractionally enriched protein yield expected backbone connectivities, and did not show amino acid biases in this work, with one exception. When adding 10% u-(13)C glucose to expression media at induction, there is poor preservation of (13)Cα-(13)Cβ spin pairs in the amino acids ILV, leading to the absence of Cβ signals in HNCACB spectra for ILV, a potentially useful editing effect. Enhanced fractional carbon-13 enrichment provides lower-cost routes to high throughput protein NMR studies, and makes modern protein NMR more cost-accessible.

  14. The 13th international workshop on targetry and target chemistry proceedings

    International Nuclear Information System (INIS)

    This report contains the complete proceedings of the 13th International Workshop on Targetry and Target Chemistry. The Workshop was held at Risoe National Laboratory for Sustainable Energy on July 26-28 2010. The workshop deals with the development of methods and systems for efficient production of radioactive isotopes with accelerators. The WTTC series of workshops was initiated for the purpose of exchanging information about the problems and solutions associated with the production of radioisotopes for biomedical research and their applications to the diagnosis and treatment of disease. The goal of the WTTC is to advance the science associated with radioisotope production targetry. The Workshops are designed to bring experienced targetry scientists together with newcomers to the field, both from industry and academia, to discuss issues of targetry and target chemistry and approaches to exploring in situ target chemistry and the engineering required to optimize production yields. In the workshop, experience, ideas and information are freely and openly shared; learning and collaborations are fostered, with active participation by all attendees. This participation includes both formal and informal sessions. The present proceedings captures both submitted abstracts and the actual presentations showed during the very successful workshop meeting number 13 in the row, the WTTC13. (Author)

  15. The 13th international workshop on targetry and target chemistry proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Haroun, S. (SFU, TRIUMF (Canada)); Givskov, A.; Jensen, Mikael (Technical Univ. of Denmark. Risoe National Laboratory for Sustainable Energy, Radiation Research Division, Roskilde (Denmark))

    2011-06-15

    This report contains the complete proceedings of the 13th International Workshop on Targetry and Target Chemistry. The Workshop was held at Risoe National Laboratory for Sustainable Energy on July 26-28 2010. The workshop deals with the development of methods and systems for efficient production of radioactive isotopes with accelerators. The WTTC series of workshops was initiated for the purpose of exchanging information about the problems and solutions associated with the production of radioisotopes for biomedical research and their applications to the diagnosis and treatment of disease. The goal of the WTTC is to advance the science associated with radioisotope production targetry. The Workshops are designed to bring experienced targetry scientists together with newcomers to the field, both from industry and academia, to discuss issues of targetry and target chemistry and approaches to exploring in situ target chemistry and the engineering required to optimize production yields. In the workshop, experience, ideas and information are freely and openly shared; learning and collaborations are fostered, with active participation by all attendees. This participation includes both formal and informal sessions. The present proceedings captures both submitted abstracts and the actual presentations showed during the very successful workshop meeting number 13 in the row, the WTTC13. (Author)

  16. Simulation of soil organic carbon in different soil size fractions using 13Carbon measurement data

    Science.gov (United States)

    Gottschalk, P.; Bellarby, J.; Chenu, C.; Foereid, B.; Wattenbach, M.; Zingore, S.; Smith, J.

    2009-04-01

    We simulate the soil organic carbon (SOC) dynamics at a chronoseqeunce site in France, using the Rothamsted Carbon model. The site exhibits a transition from C3 plants, dominated by pine forest, to a conventional C4 maize rotation. The different 13C signatures of the forest plants and maize are used to distinguish between the woodland derived carbon (C) and the maize derived C. The model is evaluated against total SOC and C derived from forest and maize, respectively. The SOC dynamics of the five SOC pools of the model, decomposable plant material (DPM), resistant plant material (RPM), biomass, humus and inert C, are also compared to the SOC dynamics measured in different soil size fractions. These fractions are > 50 μm (particulate organic matter), 2-50 μm (silt associated SOC) and 50 μm and the sum of the other pools corresponds well to the SOC measured in the soil size fraction stocks in the first 20 years after land-use change and overestimates the C accumulation of maize C. Several hypotheses were tested to evaluate the simulations. Input data and internal model parameter uncertainties had minor effects on the simulations results. Accounting for erosion and implementing a simple tillage routine did not improve the simulation fit to the data. We therefore hypothesize that a generic process that is not yet explicitly accounted for in the ROTHC model could explain the loss in soil C after land use change. Such a process could be the loss of the physical protection of soil organic matter as would be observed following cultivation of a previously uncultivated soil. Under native conditions a fraction of organic matter is protected in stable soil aggregates. These aggregates are physically disrupted by continuous and repeated cultivation of the soil. The underestimation of SOC loss by the model can be mainly attributed to the slow turnover of the humus pool. This pool was shown to represent mainly the SOC associated with the silt and clay soil fraction. Here, the

  17. A Large Metabolic Carbon Ccontribution to the δ13C Record in Marine Aragonitic Bivalve Shells

    Science.gov (United States)

    Gillikin, D. P.; Lorrain, A.; Dehairs, F.

    2006-12-01

    The stable carbon isotopic signature archived in bivalve shells was originally thought to record the δ13C of seawater dissolved inorganic carbon13C-DIC). However, more recent studies have shown that the incorporation of isotopically light metabolic carbon (M) significantly affects the δ13C signal recorded in biogenic carbonates. To assess the M contribution to Mercenaria mercenaria shells collected in North Carolina, USA, we sampled seawater δ13C-DIC, tissue, hemolymph and shell δ13C. We found up to a 4‰ decrease through ontogeny in shell δ13C in a 23 year old individual. There was no correlation between shell height or age and tissue δ13C. Thus, the ontogenic decrease observed in the shell δ13C could not be attributed to changes in food sources as the animal ages leading to more negative metabolic CO2, since this would require a negative relationship between tissue δ13C and shell height. Hemolymph δ13C, on the other hand, did exhibit a negative relationship with height, but the δ13C values were more positive than expected, indicating that hemolymph may not be a good proxy of extrapallial fluid δ13C. Nevertheless, the hemolymph data indicate that respired CO2 does influence the δ13C of internal fluids and that the amount of respired CO2 is related to the age of the bivalve. The percent metabolic C incorporated into the shell (%M) was significantly higher (up to 37%) than has been found in other bivalve shells, which usually contain less than 10 %M. Attempts to use shell biometrics to predict %M could not explain more than ~60% of the observed variability. Moreover, there were large differences in the %M between different sites. Thus, the metabolic effect on shell δ13C cannot easily be accounted for to allow reliable δ13C-DIC reconstructions. However, there does seem to be a common effect of size, as all sites had indistinguishable slopes between the %M and shell height (+0.19% per mm of shell height).

  18. The Range of 1-3 keV Electrons in Solid Oxygen and Carbon Monoxide

    DEFF Research Database (Denmark)

    Oehlenschlæger, M.; Andersen, H.H.; Schou, Jørgen;

    1985-01-01

    The range of 1-3 keV electrons in films of solid oxygen and carbon monoxide has been measured by a mirror substrate method. The technique used here is identical to the one previously used for range measurements in solid hydrogen and nitrogen. The range in oxygen is slightly shorter than that in...... nitrogen whereas the range in carbon monoxide is about 20% larger than that in the nitrogen....

  19. 13C Incorporation into Signature Fatty Acids as an Assay for Carbon Allocation in Arbuscular Mycorrhiza

    Science.gov (United States)

    Olsson, Pål Axel; van Aarle, Ingrid M.; Gavito, Mayra E.; Bengtson, Per; Bengtsson, Göran

    2005-01-01

    The ubiquitous arbuscular mycorrhizal fungi consume significant amounts of plant assimilated C, but this C flow has been difficult to quantify. The neutral lipid fatty acid 16:1ω5 is a quantitative signature for most arbuscular mycorrhizal fungi in roots and soil. We measured carbon transfer from four plant species to the arbuscular mycorrhizal fungus Glomus intraradices by estimating 13C enrichment of 16:1ω5 and compared it with 13C enrichment of total root and mycelial C. Carbon allocation to mycelia was detected within 1 day in monoxenic arbuscular mycorrhizal root cultures labeled with [13C]glucose. The 13C enrichment of neutral lipid fatty acid 16:1ω5 extracted from roots increased from 0.14% 1 day after labeling to 2.2% 7 days after labeling. The colonized roots usually were more enriched for 13C in the arbuscular mycorrhizal fungal neutral lipid fatty acid 16:1ω5 than for the root specific neutral lipid fatty acid 18:2ω6,9. We labeled plant assimilates by using 13CO2 in whole-plant experiments. The extraradical mycelium often was more enriched for 13C than was the intraradical mycelium, suggesting rapid translocation of carbon to and more active growth by the extraradical mycelium. Since there was a good correlation between 13C enrichment in neutral lipid fatty acid 16:1ω5 and total 13C in extraradical mycelia in different systems (r2 = 0.94), we propose that the total amount of labeled C in intraradical and extraradical mycelium can be calculated from the 13C enrichment of 16:1ω5. The method described enables evaluation of C flow from plants to arbuscular mycorrhizal fungi to be made without extraction, purification and identification of fungal mycelia. PMID:15870350

  20. Levels in 13N examined by 12C+p elastic resonance scattering with thick target

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The elastic resonance scattering of 12C+p has been studied in inverse kinematics via a novel thick target method at GIRAFFE facility of HI-13 tandem accelerator laboratory,Beijing.The recoil protons were measured by a △E-E counter telescope based on a large area double-sided silicon strip detector at laboratory angles around θ0=15°.The excitation function for 12C(p,p)elastic scattering has been obtained over a wide energy range of Ec.m.=0.31-3.45 MeV,which was explained quite well by the R-matrix calculation with known resonance parameters of the first three levels in 13N nucleus.Thus it is demonstrated that the present setup can be directly applied to the study of elastic resonance scattering with secondary radioactive beams.

  1. The 13th International Workshop on Targetry and Target Chemistry Proceedings

    DEFF Research Database (Denmark)

    Haroun, Samar; Givskov, Alex David; Jensen, Mikael

    This report contains the complete proceedings of the 13th International Workshop on Targetry and Target Chemistry. The Workshop was held at Risø National Laboratory for Sustainable Energy on July 26-28 2010. The workshop deals with the development of methods and systems for efficient production...... of radioactive isotopes with accelerators. The WTTC series of workshops was initiated for the purpose of exchanging information about the problems and solutions associated with the production of radioisotopes for biomedical research and their applications to the diagnosis and treatment of disease. The goal...... of the WTTC is to advance the science associated with radioisotope production targetry. The Workshops are designed to bring experienced targetry scientists together with newcomers to the field, both from industry and academia, to discuss issues of targetry and target chemistry and approaches to exploring...

  2. Characteristics of 14C and 13C of carbonate aerosols in dust storm events in China

    Science.gov (United States)

    Chen, Bing; Jie, Dongmei; Shi, Meinan; Gao, Pan; Shen, Zhenxing; Uchida, Masao; Zhou, Liping; Liu, Kexin; Hu, Ke; Kitagawa, Hiroyuki

    2015-10-01

    In contrast with its decrease in western China deserts, the dust storm event in eastern China, Korea, and Japan shows an increase in frequency. Although the drylands in northeastern China have been recognized as an important dust source, the relative contributions of dust transport from the drylands and deserts are inconclusive, thus the quantification of dust storm sources in downwind area remains a challenge. We measured the 14C and 13C contents in carbonates of dust samples from six sites in China, which were collected for the duration of dust storm events in drylands, deserts, and urban areas. The δ13C of the dryland dust samples considerably varied in a range of - 9.7 to - 5.0‰, which partly overlapped the desert dust carbonate δ13C ranges. The 14C content of the dryland dust carbonates showed a narrow range of 60.9 ± 4.0 (as an average and 1 SD of five samples) percent modern carbon (pMC), indicating the enrichment of modern carbonate. Dust samples in desert regions contained relatively aged carbonates with the depleting 14C showing of 28.8 ± 3.3 pMC. After the long-range transport of the western China desert dust plume, the carbonates collected at the southern China remained the depletion of 14C (33.5 ± 5.3 pMC) as in the desert regions. On the other hand, the samples of dust storm events at the urban areas of eastern China showed an enrichment of 14C contents (46.2 ± 5.0 pMC, n = 7), which might be explained by the stronger contribution of modern-carbonate-rich dryland dust.

  3. Low carbon and clean energy scenarios for India: Analysis of targets approach

    International Nuclear Information System (INIS)

    Low carbon energy technologies are of increasing importance to India for reducing emissions and diversifying its energy supply mix. Using GCAM, an integrated assessment model, this paper analyzes a targets approach for pushing solar, wind, and nuclear technologies in the Indian electricity generation sector from 2005 to 2095. Targets for these technologies have been constructed on the basis of Indian government documents, policy announcements, and expert opinions. Different targets have been set for the reference scenario and the carbon price scenario. In the reference scenario, wind and nuclear technologies exceed respective targets in the long run without any subsidy push, while solar energy requires subsidy push throughout the century in order to meet its high targets. In the short run, nuclear energy also requires significant subsidy, including a much higher initial subsidy relative to solar power, which is a result of its higher targets. Under a carbon price scenario, the carbon price drives the penetration of these technologies. Still, subsidy is required — especially in the short run when the carbon price is low. We also found that pushing solar, wind, and nuclear technologies leads to a decrease in share of CCS under the carbon price scenario and biomass under both the reference and carbon price scenarios. This is because low carbon technologies compete among themselves and substitute each other, thereby enhancing the need for subsidy or carbon price, highlighting that proposed targets are not set at efficient levels. In light of contemporary debate on external costs of nuclear energy, we also assess the sensitivity of the results to nuclear technology cost. We find that higher cost significantly decreases the share of nuclear power under both the reference and carbon price scenarios.

  4. Spatiotemporal patterns of carbon-13 in the global surface oceans and the oceanic Suess effect

    NARCIS (Netherlands)

    Gruber, N.; Keeling, C.D.; Bacastow, R.B.; Guenther, P.R.; Lueker, T.J.; Wahlen, M.; Meijer, H.A.J.; Mook, W.G.; Stocker, T.F.

    1999-01-01

    A global synthesis of the C-13/C-12 ratio of dissolved inorganic carbon (DIC) in the surface ocean is attempted by summarizing high-precision data obtained from 1978 to 1997 in all major ocean basins. The data, mainly along transects but including three subtropical time series, are accompanied by si

  5. Triblock Copolymers Based on 1,3-Trimethylene Carbonate and Lactide as Biodegradable Thermoplastic Elastomers

    NARCIS (Netherlands)

    Zhang, Zheng; Grijpma, Dirk W.; Feijen, Jan

    2004-01-01

    Biodegradable triblock copolymers based on 1,3-trimethylene carbonate (TMC) and different lactides (i.e. D,L-lactide(DLLA), L-lactide (LLA), D-lactide (DLA)) designated as poly(DLLA-TMC-DLLA), poly(LLA-TMC-LLA) and poly(DLA-TMC-DLA) were prepared and their mechanical and thermal properties were comp

  6. Soil carbon inventories and d 13C along a moisture gradient in Botswana

    NARCIS (Netherlands)

    Bird, M.I.; Veenendaal, E.M.; Lloyd, J.

    2004-01-01

    We present a study of soil organic carbon (SOC) inventories and d 13C values for 625 soil cores collected from well-drained, coarse-textured soils in eight areas along a 1000 km moisture gradient from Southern Botswana, north into southern Zambia. The spatial distribution of trees and grass in the d

  7. Determination of the δ13C of dissolved inorganic carbon in water; RSIL lab code 1710

    Science.gov (United States)

    Singleton, Glenda L.; Revesz, Kinga; Coplen, Tyler B.

    2012-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1710 is to present a method to determine the δ13C of dissolved inorganic carbon (DIC) of water. The DIC of water is precipitated using ammoniacal strontium chloride (SrCl2) solution to form strontium carbonate (SrCO3). The δ13C is analyzed by reacting SrCO3 with 100-percent phosphoric acid (H3PO4) to liberate carbon quantitatively as carbon dioxide (CO2), which is collected, purified by vacuum sublimation, and analyzed by dual inlet isotope-ratio mass spectrometry (DI-IRMS). The DI-IRMS is a DuPont double-focusing mass spectrometer. One ion beam passes through a slit in a forward collector and is collected in the rear collector. The other measurable ion beams are collected in the front collector. By changing the ion-accelerating voltage under computer control, the instrument is capable of measuring mass/charge (m/z) 45 or 46 in the rear collector and m/z 44 and 46 or 44 and 45, respectively, in the front collector. The ion beams from these m/z values are as follows: m/z 44 = CO2 = 12C16O16O, m/z 45 = CO2 = 13C16O16O primarily, and m/z 46 = CO2 = 12C16O18O primarily. The data acquisition and control software calculates δ13C values.

  8. Neoproterozoic diamictite-cap carbonate succession and δ13C chemostratigraphy from eastern Sonora, Mexico

    Science.gov (United States)

    Corsetti, Frank A.; Stewart, John H.; Hagadorn, James W.

    2007-01-01

    Despite the occurrence of Neoproterozoic strata throughout the southwestern U.S. and Sonora, Mexico, glacial units overlain by enigmatic cap carbonates have not been well-documented south of Death Valley, California. Here, we describe in detail the first glaciogenic diamictite and cap carbonate succession from Mexico, found in the Cerro Las Bolas Group. The diamictite is exposed near Sahuaripa, Sonora, and is overlain by a 5 m thick very finely-laminated dolostone with soft sediment folds. Carbon isotopic chemostratigraphy of the finely-laminated dolostone reveals a negative δ13C anomaly (down to − 3.2‰ PDB) characteristic of cap carbonates worldwide. Carbon isotopic values rise to + 10‰ across ∼ 400 m of section in overlying carbonates of the Mina el Mezquite and Monteso Formations. The pattern recorded here is mostly characteristic of post-Sturtian (ca. ≤ 700 Ma), but pre-Marinoan (ca. ≥ 635 Ma) time. However, the Cerro Las Bolas Group shares ambiguity common to most Neoproterozoic successions: it lacks useful radiometric age constraints and biostratigraphically useful fossils, and its δ13C signature is oscillatory and therefore somewhat equivocal.

  9. Toward microtesla MRI of hyperpolarized carbon-13 for real-time metabolic imaging

    CERN Document Server

    Zotev, V S; Savukov, I M; Matlashov, A N; Gómez, J J; Espy, M A

    2009-01-01

    Hyperpolarization of carbon-13 is a promising technique that has enabled MR angiography, perfusion mapping, and real-time metabolic imaging of C-13 labeled organic substances with unprecedented signal-to-noise levels. Because the hyperpolarization is performed outside an MRI scanner (using a special NMR-style hyperpolarizer), high magnetic fields of conventional MRI systems offer little advantage in terms of achievable C-13 polarization. Here we propose an ultimate low-field MRI scanner for imaging hyperpolarized C-13. It uses only microtesla-range magnetic fields and employs SQUID (superconducting quantum interference device) sensors for broadband reception of MRI signals. We present the first images acquired by SQUID-based microtesla MRI with dynamic nuclear polarization (Overhauser enhancement). We also report the first NMR spectra of C-13 at microtesla fields, including spectra of metabolically relevant sodium pyruvate, bicarbonate, and alanine. Our results demonstrate feasibility and potential of the pro...

  10. Kinetic isotope effect of carbon-13 in decarboxylation of phenylpropiolic acid in anhydrous formic acid

    International Nuclear Information System (INIS)

    Carbon-13 kinetic isotope effects in the decarboxylation of phenylpropiolic acid (carboxyl-13C) in formic acid medium and in the decarbonylation of liquid formic acid assisted with phenylpropiolic acid (PPA) and acetophenone (AP) have been studied in the 70-100oC temperature interval. The carboxyl-13C KIEs are in the range 1.0034 at 71.6oC and 1.0047 at 101.2oC respectively. The C-13C KIE, k-12/k-13, in the decarbonylation of liquid formic acid assisted with PPA were found to be of 1.0419 at 71.6oC and 1.0383 at 101.2oC. The C-13 KIE in the decarbonylation of pure formic acid are 1.0464 at 70.2oC and 1.0411 at 98oC respectively. The above experimental results have been discussed and interpreted as indicating that the formation of Cα-H bond preceded by the protonation of triple acetylenic bond of PPA is the rate determining step followed by carbon dioxide splitting. The 13-CO-KIE in the carbon monooxide generation assisted with PPA is much larger than the 13-CO-KIE generated in the presence of phenylacetylene. This shows that the decarboxylation of PPA and decarboxylation of FA are interrelated processes proceeding in the reaction cage. The formic acid involved in the formation of TS is decarbonylating directly avoiding probably largely the formic acid anhydride intermediate formation. (author)

  11. Quantifying the chemical composition of soil organic carbon with solid-state 13C NMR

    Science.gov (United States)

    Baldock, J. A.; Sanderman, J.

    2011-12-01

    The vulnerability of soil organic carbon (SOC) to biological decomposition and mineralisation to CO2 is defined at least partially by its chemical composition. Highly aromatic charcoal-like SOC components are more stable to biological decomposition than other forms of carbon including cellulose. Solid-state 13C NMR has gained wide acceptance as a method capable of defining SOC chemical composition and mathematical fitting processes have been developed to estimate biochemical composition. Obtaining accurate estimates depends on an ability to quantitatively detect all carbon present in a sample. Often little attention has been paid to defining the proportion of organic carbon present in a soil that is observable in solid-state 13C NMR analyses of soil samples. However, if such data is to be used to inform carbon cycling studies, it is critical that quantitative assessments of SOC observability be undertaken. For example, it is now well established that a significant discrimination exists against the detection of the low proton content polyaromatic structures typical of charcoal using cross polarisation 13C NMR analyses. Such discrimination does not exist where direct polarisation analyses are completed. In this study, the chemical composition of SOC as defined by cross polarisation and direct polarisation13C NMR analyses will be compared for Australian soils collected from under a diverse range of agricultural managements and climatic conditions. Results indicate that where significant charcoal C contents exist, it is highly under-represented in the acquired CP spectra. For some soils, a discrimination against alkyl carbon was also evident. The ability to derive correction factors to compensate for such discriminations will be assessed and presented.

  12. Usefulness of targeting lymphocyte Kv1.3-channels in the treatment of respiratory diseases.

    Science.gov (United States)

    Kazama, Itsuro; Tamada, Tsutomu; Tachi, Masahiro

    2015-10-01

    T lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes. Patch-clamp studies revealed that the channels play crucial roles in facilitating the calcium influx necessary to trigger lymphocyte activation and proliferation. Using selective channel inhibitors in experimental animal models, in vivo studies further revealed the clinically relevant relationship between the channel expression and the development of chronic respiratory diseases, in which chronic inflammation or the overstimulation of cellular immunity in the airways is responsible for the pathogenesis. In chronic respiratory diseases, such as chronic obstructive pulmonary disease, asthma, diffuse panbronchiolitis and cystic fibrosis, in addition to the supportive management for the symptoms, the anti-inflammatory effects of macrolide antibiotics were shown to be effective against the over-activation or proliferation of T lymphocytes. Recently, we provided physiological and pharmacological evidence that macrolide antibiotics, together with calcium channel blockers, HMG-CoA reductase inhibitors, and nonsteroidal anti-inflammatory drugs, effectively suppress the Kv1.3-channel currents in lymphocytes, and thus exert anti-inflammatory or immunomodulatory effects. In this review article, based on the findings obtained from recent in vivo and in vitro studies, we address the novel therapeutic implications of targeting the lymphocyte Kv1.3-channels for the treatment of chronic or acute respiratory diseases.

  13. Synthesis of carbon-11, fluorine-18, and nitrogen-13 labeled radiotracers for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, J.S.; Wolf, A.P.

    1981-01-01

    A number of reviews, many of them recent, have appeared on various aspects of /sup 11/C, /sup 18/F and /sup 13/N-labeled radiotracers. This monograph treats the topic principally from the standpoint of synthetic organic chemistry while keeping in perspective the necessity of integrating the organic chemistry with the design and ultimate application of the radiotracer. Where possible, recent examples from the literature of organic synthesis are introduced to suggest potentially new routes which may be applied to problems in labeling organic molecules with the short-lived positron emitters, carbon-11, fluorine-18, and nitrogen-13. The literature survey of carbon-11, fluorine-18 and nitrogen-13 labeled compounds presented are of particular value to scientists working in this field. Two appendices are also included to provide supplementary general references. A subject index concludes this volume.

  14. Synthesis of carbon-11, fluorine-18, and nitrogen-13 labeled radiotracers for biomedical applications

    International Nuclear Information System (INIS)

    A number of reviews, many of them recent, have appeared on various aspects of 11C, 18F and 13N-labeled radiotracers. This monograph treats the topic principally from the standpoint of synthetic organic chemistry while keeping in perspective the necessity of integrating the organic chemistry with the design and ultimate application of the radiotracer. Where possible, recent examples from the literature of organic synthesis are introduced to suggest potentially new routes which may be applied to problems in labeling organic molecules with the short-lived positron emitters, carbon-11, fluorine-18, and nitrogen-13. The literature survey of carbon-11, fluorine-18 and nitrogen-13 labeled compounds presented are of particular value to scientists working in this field. Two appendices are also included to provide supplementary general references. A subject index concludes this volume

  15. Restorative effect of (5E, 13E)-5,13-Docosadienoic acid on carbon tetrachloride induced oxidative stress in rats

    Institute of Scientific and Technical Information of China (English)

    Anand Thiru; Gokulakrishnan Kannan; Kalaiselvan Ashokan; Velavan Sivanandam

    2012-01-01

    Objective: To evaluate the restorative effect of (5E, 13E)-5,13-Docosadienoic acid on carbon tetrachloride induced oxidative stress in rats. Methods: Wistar strain male albino rats, weighing 180-200 g/bw were selected for the study. Rats were divided into four groups. Group I animals were served as normal control. Group II was administered with corn oil (3 ml/kg, i.p.) as vehicle control. Group III was given single dose (29th day) of CCl4 in corn oil (1:1 v/v, 3 ml/kg, i.p.). Groups IV was treated with (5E, 13E)-5,13-Docosadienoic acid (DA) (6 mg/kg body weight) for 28 days and given single dose of (29th day) CCl4 in corn oil (1:1 v/v, 3 ml/kg, i.p.). Six hours after CCl4 intoxication, the experimental animals were sacrificed. The blood samples were collected. Liver was excised immediately and immersed in physiological saline. Results: The lipid peroxidation was initiated in CCl4 intoxicated rats which is evidenced by thiobarbituric acid (TBARS) and diminution of GSH content in liver. Super oxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), vitamin C and E in CCl4 intoxicated rats retrieved towards near normalcy. After treating with DA which significantly altered (P<0.001) serum marker enzyme level and antioxidant level near normal against CCl4 treated rats. Conclusions: It was observed that the entire variable tested i.e., SOD, CAT, GPx, reduced glutathione, vitamin C and E recorded a significant decline on CCl4 treatment. However, treatment with DA restored the levels to near normal value, suggesting the therapeutic effect of DA to counter the oxidative stress.

  16. Measurement of carbon deposit at to irradiate a target; Medicion del deposito de carbon al irradiar un blanco

    Energy Technology Data Exchange (ETDEWEB)

    Rosales M, P.; Aguilera R, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    Backscattering data obtained when bombarding a thin target of {sup 12} C deposited on a thick substrate of Ta are analyzed, with a ion beam of {sup 12} C for high fluences and different energy between 9.85 and 13 MeV. A variation in the thickness of the target is observed and is found its correlation with the fluence in the target. (Author)

  17. Energy technologies evaluated against climate targets using a cost and carbon trade-off curve.

    Science.gov (United States)

    Trancik, Jessika E; Cross-Call, Daniel

    2013-06-18

    Over the next few decades, severe cuts in emissions from energy will be required to meet global climate-change mitigation goals. These emission reductions imply a major shift toward low-carbon energy technologies, and the economic cost and technical feasibility of mitigation are therefore highly dependent upon the future performance of energy technologies. However, existing models do not readily translate into quantitative targets against which we can judge the dynamic performance of technologies. Here, we present a simple, new model for evaluating energy-supply technologies and their improvement trajectories against climate-change mitigation goals. We define a target for technology performance in terms of the carbon intensity of energy, consistent with emission reduction goals, and show how the target depends upon energy demand levels. Because the cost of energy determines the level of adoption, we then compare supply technologies to one another and to this target based on their position on a cost and carbon trade-off curve and how the position changes over time. Applying the model to U.S. electricity, we show that the target for carbon intensity will approach zero by midcentury for commonly cited emission reduction goals, even under a high demand-side efficiency scenario. For Chinese electricity, the carbon intensity target is relaxed and less certain because of lesser emission reductions and greater variability in energy demand projections. Examining a century-long database on changes in the cost-carbon space, we find that the magnitude of changes in cost and carbon intensity that are required to meet future performance targets is not unprecedented, providing some evidence that these targets are within engineering reach. The cost and carbon trade-off curve can be used to evaluate the dynamic performance of existing and new technologies against climate-change mitigation goals. PMID:23560987

  18. Diethers enriched in 13C suggest carbon-limitation at the Lost City Hydrothermal Field

    Science.gov (United States)

    Bradley, A. S.; Hayes, J. M.; Summons, R. E.

    2004-12-01

    Active and inactive carbonate vent structures from the Lost City Hydrothermal Field (LCHF) contain up to 0.6% organic carbon including diverse lipids. Values of δ 13C for total organic carbon (TOC) range from -18.7‰ vs. VPDB at the active, high-temperature vent known as "The Beehive" (90° C), to -3.1‰ at Marker 7 (active, 70° C). Samples with relatively high levels of 13C also contained high amounts of isoprenoidal and nonisoprenoidal diethers. Samples more depleted in 13C lacked or contained low amounts of these diethers. The correlation between high 13C and abundant diethers is supported by compound-specific isotopic analyses. Archaeal and bacterial diethers are enriched in 13C relative to photosynthetically derived marine carbon. The biomarkers sn-2 hydroxyarchaeol, sn-3 hydroxyarchaeol, and dihydroxyarchaeol - considered diagnostic for methane-cycling archaea - had δ values ranging from -8.5 to +4.8‰ . Phylogenetic data confirms the presence at these vents of a single group of methanogens, related to the Methanosarcinales (Schrenk et al., 2004). Diethers with non-isoprenoidal alkyl chains are also present, are of presumed bacterial origin, and may indicated the presence of sulfate-reducing bacteria. Values of δ for these compounds range from -7.3 to +1.0‰ . At the Beehive vent, diether lipids are absent and the TOC is depleted in 13C. Coexistence of isotopically similar hydroxyarchaeols and nonisoprenoidal glycerol diethers is typical of marine, cold-seep environments at which concentrations of H2 are low and methane is oxidized anaerobically. At the LCHF, however, concentrations of H2 in pore waters reach 15 mM (Proskurowski et al., 2003). This H2, produced by serpentinization reactions, drives production (rather than oxidation) of methane. Simultaneously, sulfate-reducing bacteria can flourish as carbon-fixing autotrophs. Under such conditions, carbon may be the limiting substrate, its nearly complete consumption accounting for the enrichment of

  19. Legionella pneumophila Carbonic Anhydrases: Underexplored Antibacterial Drug Targets

    OpenAIRE

    Supuran, Claudiu T.

    2016-01-01

    Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes which catalyze the hydration of carbon dioxide to bicarbonate and protons. Many pathogenic bacteria encode such enzymes belonging to the α-, β-, and/or γ-CA families. In the last decade, enzymes from some of these pathogens, including Legionella pneumophila, have been cloned and characterized in detail. These enzymes were shown to be efficient catalysts for CO2 hydration, with kcat values in the range of (3.4–8.3) × 105 s−1 and kcat/KM ...

  20. Quantifying the metabolic contribution to δ13C of shell carbonate of Arctica islandica: an experimental calibration

    Science.gov (United States)

    Beirne, E. C.; Wanamaker, A. D.

    2010-12-01

    The stable isotopic composition of dissolved inorganic carbon of seawater (δ13CDIC) can provide a powerful means to investigate atmospheric and oceanic carbon dynamics. Records of past δ13CDIC values of seawater, especially from the extratropical oceans, are needed to better understand how recent climate change and anthropogenic activity (namely fossil fuel emissions) have impacted the global carbon cycle. However, long-term reconstructions of marine δ13CDIC are limited (both spatially and temporally) by a lack of suitable proxy archives, which have undergone a rigorous calibration process. Marine mollusks represent a potential δ13CDIC archive given that the primary source of carbon to their shell material is ambient dissolved inorganic carbon. However, interpretation of this archive is confounded by the additional contribution of respired (or metabolic) carbon to the carbon isotope ratio of shell material (δ13Cshell). Although theoretical models predict that less than 10% of δ13Cshell of marine mollusks is attributable to metabolic carbon, several studies have reported significantly larger contributions of respired carbon (CM) to shell material depending upon the species in question, and in some cases, ontogenetic age. Therefore, species-specific calibrations must be conducted to establish metabolic contribution to δ13Cshell at different stages of ontogeny. The central objective of this study was to quantify the metabolic contribution to the shell carbonate of Arctica islandica L., juveniles and adults, to determine the viability of this species as a paleo-δ13CDIC archive. Results will be presented from an 8-month experimental calibration between δ13CDIC and δ13Cshell of the species Arctica islandica. Adults (25 to 55 years old) and juveniles (1mm/month) allowed for the measurement of three distinct growth periods in order to capture seasonal variability in metabolic carbon incorporation. δ13CDIC was measured every two weeks during the course of the

  1. Compositions and methods for cancer treatment using targeted carbon nanotubes

    Science.gov (United States)

    Harrison, Jr., Roger G; Resasco, Daniel E; Neves, Luis Filipe Ferreira

    2013-08-27

    The present invention is a method for detecting and destroying cancer tumors. The method is based on the concept of associating a linking protein or linking peptide such as, but not limited to, annexin V or other annexins to carbon nanotubes such as single-walled carbon nanotubes (SWNTs) to form a protein-CNT complex. Said linking protein or peptide can selectively bind to cancerous cells, especially tumor vasculature endothelial cells, rather than to healthy ones by binding to cancer-specific external receptors such as anionic phospholipids including phosphatidylserine expressed on the outer surfaces of cancer cells only. Irradiation of bound CNTs with one or more specific electromagnetic wavelengths is then used to detect and destroy those cells to which the CNTs are bound via the linking protein or peptide thereby destroying the tumor or cancer cells and preferably an immunostimulant is provided to the patient to enhance the immune response against antigens released from the tumor or cancer cells.

  2. Design of an Intense Muon Source with a Carbon and Mercury Target

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, Diktys [Brookhaven; Berg, J. Scott [Brookhaven; Neuffer, David [Fermilab; Ding, Xiaoping [UCLA

    2015-06-01

    In high-intensity sources, muons are produced by firing high energy protons onto a target to produce pions. The pions decay to muons which are captured and accelerated. In the present study, we examine the performance of the channel for two different target scenarios: one based on liquid mercury and another one based on a solid carbon target. We produce distributions with the two different target materials and discuss differences in particle spectrum near the sources. We then propagate the distributions through our capture system and compare the full system performance for the two target types.

  3. Multi-functionalized single-walled carbon nanotubes as tumor cell targeting biological transporters

    International Nuclear Information System (INIS)

    Multi-functionalized single walled carbon nanotubes (SWNTs) were prepared and applied as tumor cell targeting biological transporters. A positive charge was introduced on SWNTs to get high loading efficiency of fluorescein (FAM) labeled short double strands DNA (20 base pairs). The SWNTs were encapsulated with the folic acid modified phospholipids for active targeting into tumor cell. The tumor cell-targeting properties of these multi-functionalized SWNTs were investigated by active targeting into mouse ovarian surface epithelial cells. The experimental results show that these multi-functionalized SWNTs have good tumor cell targeting property

  4. Evaluation of carbon diffusion in heat treatment of H13 tool steel under different atmospheric conditions

    Directory of Open Access Journals (Sweden)

    Maziar Ramezani

    2015-04-01

    Full Text Available Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of heat treatment experiments had been conducted under different atmospheric conditions and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat treatment without atmospheric control, heat treatment with stainless steel foil wrapping, pack carburization heat treatment and vacuum heat treatment. The results showed that stainless steel foil wrapping could restrict decarburization process, resulting in a constant hardness profile as vacuum heat treatment does. However, the tempering characteristic between these two heat treatment methods is different. Results from the gas nitrided samples showed that the thickness and the hardness of the nitrided layer is independent of the carbon content in H13 steel.

  5. Hyaluronic acid modified mesoporous carbon nanoparticles for targeted drug delivery to CD44-overexpressing cancer cells

    Science.gov (United States)

    Wan, Long; Jiao, Jian; Cui, Yu; Guo, Jingwen; Han, Ning; Di, Donghua; Chang, Di; Wang, Pu; Jiang, Tongying; Wang, Siling

    2016-04-01

    In this paper, hyaluronic acid (HA) functionalized uniform mesoporous carbon spheres (UMCS) were synthesized for targeted enzyme responsive drug delivery using a facile electrostatic attraction strategy. This HA modification ensured stable drug encapsulation in mesoporous carbon nanoparticles in an extracellular environment while increasing colloidal stability, biocompatibility, cell-targeting ability, and controlled cargo release. The cellular uptake experiments of fluorescently labeled mesoporous carbon nanoparticles, with or without HA functionalization, demonstrated that HA-UMCS are able to specifically target cancer cells overexpressing CD44 receptors. Moreover, the cargo loaded doxorubicin (DOX) and verapamil (VER) exhibited a dual pH and hyaluronidase-1 responsive release in the tumor microenvironment. In addition, VER/DOX/HA-UMCS exhibited a superior therapeutic effect on an in vivo HCT-116 tumor in BALB/c nude mice. In summary, it is expected that HA-UMCS will offer a new method for targeted co-delivery of drugs to tumors overexpressing CD44 receptors.

  6. Monitoring of liver glycogen synthesis in diabetic patients using carbon-13 MR spectroscopy

    International Nuclear Information System (INIS)

    To investigate the relationship between liver glucose, glycogen, and plasma glucose in diabetic patients, in vivo liver carbon-13 magnetic resonance spectroscopy (13C MRS) with a clinical 3.0 T MR system was performed. Subjects were healthy male volunteers (n = 5) and male type-2 diabetic patients (n = 5). Pre- and during oral glucose tolerance tests (OGTT), 13C MR spectra without proton decoupling were acquired in a monitoring period of over 6 h, and in total seven spectra were obtained from each subject. For OGTT, 75 g of glucose, including 5 g of [1-13C]glucose, was administered. The MR signals of liver [1-13C]glucose and glycogen were detected and their time-course changes were assessed in comparison with the plasma data obtained at screening. The correlations between the fasting plasma glucose level and liver glycogen/glucose rate (Spearman: ρ = -0.68, p 13C MRS can perform noninvasive measurement of glycogen storage/degradation ability in the liver individually and can assist in tailor-made therapy for diabetes. In conclusion, 13C MRS has a potential to become a powerful tool in diagnosing diabetes multilaterally.

  7. Evaluation of carbon diffusion in heat treatment of H13 tool steel under different atmospheric conditions

    OpenAIRE

    Maziar Ramezani; Timotius Pasang; Zhan Chen; Thomas Neitzert; Dominique Au

    2015-01-01

    Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of heat treatment experiments had been conducted under different atmospheric conditions and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat treatment without atmospheric contro...

  8. STUDIES OF MAIN CHAIN DYNAMICS OF FLUORINE-CONTAINING IONOMERS BY CARBON-13 NUCLEAR MAGNETIC RELAXATION

    Institute of Scientific and Technical Information of China (English)

    YANG Yanwu; WANG Dehua; QIU Jianqing; QIAN Baogong; WANG Hongzuo

    1992-01-01

    The carbon-13 spin-spin relaxation times of fluorine-containing ionomers are measured and motional correlation times τ0 and τd are calculated by using VJGM model. The results show that the motions of polymer main chain in ionomers become more difficult with increasing of ionization degree and contents of functional group, and depend on the fine structures and stability of ionic microdomains.

  9. Histone modification enhances the effectiveness of IL-13 receptor targeted immunotoxin in murine models of human pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Puri Raj K

    2011-04-01

    Full Text Available Abstract Background Interleukin-13 Receptor α2 (IL-13Rα2 is a tumor-associated antigen and target for cancer therapy. Since IL-13Rα2 is heterogeneously overexpressed in a variety of human cancers, it would be highly desirable to uniformly upregulate IL-13Rα2 expression in tumors for optimal targeting. Methods We examined epigenetic regulation of IL-13Rα2 in a murine model of human pancreatic cancer by Bisulfite-PCR, sequencing for DNA methylation and chromatin immunoprecipitation for histone modification. Reverse transcription-PCR was performed for examining changes in IL-13Rα2 mRNA expression after treatment with histone deacetylase (HDAC and c-jun inhibitors. In vitro cytotoxicity assays and in vivo testing in animal tumor models were performed to determine whether HDAC inhibitors could enhance anti-tumor effects of IL-13-PE in pancreatic cancer. Mice harboring subcutaneous tumors were treated with HDAC inhibitors systemically and IL-13-PE intratumorally. Results We found that CpG sites in IL-13Rα2 promoter region were not methylated in all pancreatic cancer cell lines studied including IL-13Rα2-positive and IL-13Rα2-negative cell lines and normal cells. On the other hand, histones at IL-13Rα2 promoter region were highly-acetylated in IL-13Rα2-positive but much less in receptor-negative pancreatic cancer cell lines. When cells were treated with HDAC inhibitors, not only histone acetylation but also IL-13Rα2 expression was dramatically enhanced in receptor-negative pancreatic cancer cells. In contrast, HDAC inhibition did not increase IL-13Rα2 in normal cell lines. In addition, c-jun in IL-13Rα2-positive cells was expressed at higher level than in negative cells. Two types of c-jun inhibitors prevented increase of IL-13Rα2 by HDAC inhibitors. HDAC inhibitors dramatically sensitized cancer cells to immunotoxin in the cytotoxicity assay in vitro and increased IL-13Rα2 in the tumors subcutaneously implanted in the immunodeficient

  10. Acceleration of carbon-13 spin-lattice relaxation times in amino acids by electrolytes

    Institute of Scientific and Technical Information of China (English)

    Tian Jinping; Yin Yingwu

    2004-01-01

    A series of amino acids and carboxylic acids were determined by 13C NMR spectroscopy.The results showed that addition of 3M MgCl2 led to the 13C NMR integral area of samples being well proportional to number of carbon atoms that produce the particular signal with reliability over 95%. Measurements of 13C spin-lattice relaxation times (T1's) are reported for a number of amino acids. T1's of all the carbons in amino acids generally tend to decrease with the increase of the concentration of electrolytes, and the presence of magnesium slats is of significant. Carboxylic carbons in amino acids are the most sensitive "acceptor" of the 13C spin-lattice relaxation accelerating effects in electrolytes, and the 13C spin-lattice relaxation accelerating ability of electrolytes is Mg(ClO4)2 >MgCl2 >CaCl2 >NaCl >KCl >LiClO4 >NaOH. In general, T1's of C1 carbons in nonpolar a-amino acids are higher than those in polar and basic a-amino acids both in aqueous and 3M MgCl2 medium. In aliphatic straight-chain amino acids, a-, a-, a-, ai- and a- amino acids, T1's of C1 carbons tend to reduce with the increase of inserted carbon numbers between amino and carboxylic groups compared with Gly. T1's can be decreased even more when amino acids are mixed in 3M MgCl2, but T1's of carbons in amino acids decrease slightly with increase of the concentration of amino acids in 3M MgCl2. The mechanisms of the observed phenomena are discussed in terms of intermolecular interaction and paramagnetic impurity in electrolytes, large contributions of intermolecular interaction which is enhanced in electrolytes concentrate on the incoming "unsaturation" of the primary solvation shell of cations with the increase of electrolytes concentration and complexes formation of amino acids with metal ions. In electrolytes, amino acids are "anchored" to cations and molecule tumbling is slowed down, molecular rigidity is increased and molecular size is "enlarged", all of these are helpful to accelerate

  11. Specific 13C functional pathways as diagnostic targets in gastroenterology breath-tests: tricks for a correct interpretation.

    Science.gov (United States)

    Pizzoferrato, M; Del Zompo, F; Mangiola, F; Lopetuso, L R; Petito, V; Cammarota, G; Gasbarrini, A; Scaldaferri, F

    2013-01-01

    Breath tests are non-invasive, non-radioactive, safe, simple and effective tests able to determine significant metabolic alterations due to specific diseases or lack of specific enzymes. Carbon isotope (13)C, the stable-non radioactive isotope of carbon, is the most used substrate in breath testing, in which (13)C/(12)C ratio is measured and expressed as a delta value, a differences between readings and a fixed standard. (13)C/(12)C ratio is measured with isotope ratio mass spectrometry or non-dispersive isotope-selective infrared spectrometer and generally there is a good agreement between these techniques in the isotope ratio estimation. (13)C/(12)C ratio can be expressed as static measurement (like delta over baseline in urea breath test) or as dynamic measurement as percent dose recovery, but more dosages are necessary. (13)C Breath-tests are involved in many fields of interest within gastroenterology, such as detection of Helicobacter pylori infection, study of gastric emptying, assessment of liver and exocrine pancreatic functions, determination of oro-caecal transit time, evaluation of absorption and to a lesser extend detection of bacterial overgrowth. The use of every single test in a clinical setting is vary depending on accuracy and substrate costs. This review is meant to present (13)C the meaning of (13)C/(12)C ratio and static and dynamic measure and, finally, the instruments dedicated to its use in gastroenterology. A brief presentation of (13)C breath tests in gastroenterology is also provided. PMID:24443068

  12. Assessing offsets between the δ13C of sedimentary components and the global exogenic carbon pool across early Paleogene carbon cycle perturbations

    Science.gov (United States)

    Sluijs, Appy; Dickens, Gerald R.

    2012-12-01

    Negative stable carbon isotope excursions (CIEs) across the Paleocene-Eocene thermal maximum (PETM; ˜56 Ma) range between 2‰ and 7‰, even after discounting sections with truncated records. Individual carbon isotope records differ in shape and magnitude from variations in the global exogenic carbon cycle through changes in (1) the relative abundance of mixed components with different δ13C within a measured substrate, (2) isotope fractionation through physiological change, and (3) the isotope composition of the carbon source. All three factors likely influence many early Paleogene δ13C records, especially across the PETM and other hyperthermal events. We apply these concepts to late Paleocene-early Eocene (˜58-52 Ma) records from Lomonosov Ridge, Arctic Ocean. Linear regression analyses show correlations between the δ13C of total organic carbon (TOC) and two proxies for the relative contribution of terrestrial organic components to sediment TOC: the branched and isoprenoid tetraether index and palynomorphs. We use these correlations to subtract the terrestrial component from δ13CTOC and calculate marine organic matter δ13C. The results show that the magnitude of the CIE in δ13CTOC across the PETM is exaggerated relative to the magnitude of the CIE in δ13CMOM by ˜3‰ due to increased contributions of terrestrial organic carbon during the event. Collectively, all carbon isotope records across the PETM and other major climate-carbon cycle perturbations in Earth's history are potentially biased through one or more of the above factors. Indeed, it is highly unlikely that any δ13C record shows the true shape and magnitude of the CIE for the global exogenic carbon cycle. For the PETM, we conclude that CIE in the exogenic carbon cycle is likely CIE.

  13. Temperature-mediated changes in microbial carbon use efficiency and 13C discrimination

    Science.gov (United States)

    Lehmeier, Christoph A.; Ballantyne, Ford, IV; Min, Kyungjin; Billings, Sharon A.

    2016-06-01

    Understanding how carbon dioxide (CO2) flux from ecosystems feeds back to climate warming depends in part on our ability to quantify the efficiency with which microorganisms convert organic carbon (C) into either biomass or CO2. Quantifying ecosystem-level respiratory CO2 losses often also requires assumptions about stable C isotope fractionations associated with the microbial transformation of organic substrates. However, the diversity of organic substrates' δ13C and the challenges of measuring microbial C use efficiency (CUE) in their natural environment fundamentally limit our ability to project ecosystem C budgets in a warming climate. Here, we quantify the effect of temperature on C fluxes during metabolic transformations of cellobiose, a common microbial substrate, by a cosmopolitan microorganism growing at a constant rate. Biomass C specific respiration rate increased by 250 % between 13 and 26.5 °C, decreasing CUE from 77 to 56 %. Biomass C specific respiration rate was positively correlated with an increase in respiratory 13C discrimination from 4.4 to 6.7 ‰ across the same temperature range. This first demonstration of a direct link between temperature, microbial CUE, and associated isotope fluxes provides a critical step towards understanding δ13C of respired CO2 at multiple scales, and towards a framework for predicting future ecosystem C fluxes.

  14. 微波热解法制备的炭涂层对LiNi1/3Mn1/3Co1/3O2性能的影响%Influence of carbon coating prepared by microwave pyrolysis on properties of LiNi1/3Mn1/3Co1/3O2

    Institute of Scientific and Technical Information of China (English)

    韩亚梅; 张正富; 张利波; 彭金辉; 傅梦笔; C.SRINIVASAKANNAN; 杜江

    2013-01-01

    A novel synthesis method of carbon-coated LiNi1/3Mn1/3Co1/3O2 cathode material for lithium-ion battery was reported. The carbon coating was produced from a precursor, glucose, by microwave-pyrolysis method. The prepared powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF) and charge/discharge tests. XRD results indicate that the carbon coating does not change the phase structure of LiNi1/3Mn1/3Co1/3O2 material. SEM results show that the surface of spherical carbon-coated material becomes rough. Electrochemical performance results show that the carbon coating can improve the cycling performance of LiNi1/3Mn1/3Co1/3O2. The specific discharge capacity retention of the carbon-coated LiNi1/3Mn1/3Co1/3O2 reached 85.0%−96.0%at the 50th cycle at 0.2C rate, and the specific discharge capacity retention is improved at a high rate.%报道了炭包覆锂离子电池正极材料 LiNi1/3Mn1/3Co1/3O2的新工艺。炭涂层由前驱体葡萄糖通过微波热解而形成。采用X射线粉末衍射(XRD)、扫描电镜、X射线荧光测试和恒流充放电测试来表征所制备的材料。XRD结果表明,炭包覆没有改变LiNi1/3Mn1/3Co1/3O2材料的相结构。SEM结果表明,炭包覆的LiNi1/3Mn1/3Co1/3O2颗粒表面变得粗糙。充放电测试结果显示,炭包覆的 LiNi1/3Mn1/3Co1/3O2的循环性能与未包覆的相比得到提高。炭包覆的LiNi1/3Mn1/3Co1/3O2在0.2C倍率下循环50次的容量保持率由84.8%提升到95.5%,且高倍率下材料的容量保持率得到提高。

  15. Targeted carbon conservation at national scales with high-resolution monitoring.

    Science.gov (United States)

    Asner, Gregory P; Knapp, David E; Martin, Roberta E; Tupayachi, Raul; Anderson, Christopher B; Mascaro, Joseph; Sinca, Felipe; Chadwick, K Dana; Higgins, Mark; Farfan, William; Llactayo, William; Silman, Miles R

    2014-11-25

    Terrestrial carbon conservation can provide critical environmental, social, and climate benefits. Yet, the geographically complex mosaic of threats to, and opportunities for, conserving carbon in landscapes remain largely unresolved at national scales. Using a new high-resolution carbon mapping approach applied to Perú, a megadiverse country undergoing rapid land use change, we found that at least 0.8 Pg of aboveground carbon stocks are at imminent risk of emission from land use activities. Map-based information on the natural controls over carbon density, as well as current ecosystem threats and protections, revealed three biogeographically explicit strategies that fully offset forthcoming land-use emissions. High-resolution carbon mapping affords targeted interventions to reduce greenhouse gas emissions in rapidly developing tropical nations.

  16. An NGR-integrated and enediyne-energized apoprotein shows CD13-targeting antitumor activity.

    Science.gov (United States)

    Zheng, Yan-Bo; Shang, Bo-Yang; Li, Yi; Zhen, Yong-Su

    2013-03-01

    Targeting and inhibiting angiogenesis is a promising strategy for treatment of cancer. NGR peptide motif is a tumor-homing peptide, which could bind with CD13 expressed on tumor blood vessels. Lidamycin is a highly potent antitumor antibiotic, which is composed of an apoprotein (LDP) and an active enediyne chromophore (AE). Here, an NGR-integrated and enediyne-energized apoprotein composed of cyclic NGR peptide and lidamycin was developed by a two-step procedure. Firstly, we prepared the fusion protein composed of NGR peptide and LDP by recombinant DNA technology. Then, AE was reloaded to the fusion protein to get NGR-LDP-AE. Our experiments showed that NGR-LDP could bind to CD13-expressing HT-1080 cells, whereas the recombinant LDP (rLDP) showed weak binding. NGR-LDP-AE exerted highly potent cytotoxicity to cultured tumor cells in vitro. In vivo antitumor activity was evaluated in murine hepatoma 22 (H22) model and human fibrosarcoma HT-1080 model. At the tolerable dose, NGR-LDP-AE and lidamycin inhibited H22 tumor growth by 94.8 and 66.9%, and the median survival time of the mice was 62 and 37 days, respectively. In the HT-1080 model, NGR-LDP-AE inhibited tumor growth by 88.6%, which was statistically different from that of lidamycin (74.5%). Immunohistochemical study showed that NGR-LDP could bind to tumor blood vessels. Conclusively, these results demonstrate that fusion of LDP with CNGRC peptide delivers AE to tumor blood vessels and improves its antitumor activity. PMID:23206754

  17. Carbon transfer from the host to Tuber melanosporum mycorrhizas and ascocarps followed using a 13C pulse-labeling technique.

    Directory of Open Access Journals (Sweden)

    François Le Tacon

    Full Text Available Truffles ascocarps need carbon to grow, but it is not known whether this carbon comes directly from the tree (heterotrophy or from soil organic matter (saprotrophy. The objective of this work was to investigate the heterotrophic side of the ascocarp nutrition by assessing the allocation of carbon by the host to Tuber melanosporum mycorrhizas and ascocarps. In 2010, a single hazel tree selected for its high truffle (Tuber melanosporum production and situated in the west part of the Vosges, France, was labeled with (13CO2. The transfer of (13C from the leaves to the fine roots and T. melanosporum mycorrhizas was very slow compared with the results found in the literature for herbaceous plants or other tree species. The fine roots primarily acted as a carbon conduit; they accumulated little (13C and transferred it slowly to the mycorrhizas. The mycorrhizas first formed a carbon sink and accumulated (13C prior to ascocarp development. Then, the mycorrhizas transferred (13C to the ascocarps to provide constitutive carbon (1.7 mg of (13C per day. The ascocarps accumulated host carbon until reaching complete maturity, 200 days after the first labeling and 150 days after the second labeling event. This role of the Tuber ascocarps as a carbon sink occurred several months after the end of carbon assimilation by the host and at low temperature. This finding suggests that carbon allocated to the ascocarps during winter was provided by reserve compounds stored in the wood and hydrolyzed during a period of frost. Almost all of the constitutive carbon allocated to the truffles (1% of the total carbon assimilated by the tree during the growing season came from the host.

  18. Spatial targeting of conservation tillage to improve water quality and carbon retention benefits

    International Nuclear Information System (INIS)

    Conservation tillage reduces soil erosion and improves water quality in agricultural watersheds. However, the benefits of conservation tillage in carbon sequestration are the subject of controversy. Public funds are provided to farms to encourage the adoption of conservation tillage. Given the economic costs, the targeting of areas likely to achieve the greatest environmental benefits has become an important policy-making issue. A geographic information system (GIS) based modelling framework which integrated hydrologic, soil organic matter, and farm models to evaluate the spatial targeting of conservation tillage was presented. A case study applying the framework in the Fairchild Creek watershed in Ontario indicated that targeting conservation tillage based on sediment abatement goals can achieve comparable carbon retention benefits in terms of the percentage reduction of base carbon losses. Targeted subcatchments for conservation tillage varied across the watershed based on benefit to cost ratios. Conservation tillage patterns based on carbon retention goals showed similar results to sediment abatement goals but slight differences were observed because of different carbon content in the soils. The results indicated that sediment abatement may be used as an indicator in setting up program goals. The impacts of conservation programs can then be evaluated based on calibrated and validated hydrologic models in conjunction with monitoring data. Results also showed that setting carbon retention may lead to higher costs in order to achieve corresponding sediment abatement benefits. Carbon retention may not be suitable for setting as a stand-alone environmental goal for conservation programs because of the difficulties in verifying the impacts and the discrepancies between carbon and sediment benefits. It was concluded that the modelling results have important policy implications for the design of conservation stewardship programs that aim to achieve environmental

  19. Composition of Carbon-13 and Nitrogen-15 in Sediments of the Ha Long Bay

    International Nuclear Information System (INIS)

    The Ha Long Bay with beautiful landscape and rich ecosystems is being used by human to develop the economy. The Ha Long Bay is currently affected by human activities causing the sedimentary environment to be much changed. The change of the environment in the Bay was studied using the composition of carbon-13, nitrogen-15 (δ13C, δ15N) and the C/N ratio in sediment of seven cores collected within the Ha Long Bay. In the Ha Long Bay, sedimentary environment receives many source sediment supplies. The north-east of Ha Long bay receives sources from sea, it is characterized by δ13C in sediment from -8.79 to -18.01‰, value δ15N in sediment from 4.36 to 4.73 ‰ and ratio of C/N from 13 to 41, the source organic matter in sediment shows that affected by C4 plant. The centre of Ha Long Bay receives organic source from sea, it is characterized by δ13C in sediment from -16.72 to -21.58 ‰, value δ15N in sediment ranges 4.15 - 5.20 ‰, ratio of C/N in sediment from 7 to 23. The north-west of Ha Long Bay is affected by rivers, it is characterized by δ13C in sediment range from -13.64 to -25.77 ‰, value δ15N in sediment from 2.50 to 4.38 ‰, and ratio C/N from 9 to 19. (author)

  20. New agents for targeting of IL-13RA2 expressed in primary human and canine brain tumors.

    Directory of Open Access Journals (Sweden)

    Waldemar Debinski

    Full Text Available Interleukin 13 receptor alpha 2 (IL-13RA2 is over-expressed in a vast majority of human patients with high-grade astrocytomas like glioblastoma. Spontaneous astrocytomas in dogs resemble human disease and have been proposed as translational model system for investigation of novel therapeutic strategies for brain tumors. We have generated reagents for both detection and therapeutic targeting of IL-13RA2 in human and canine brain tumors. Peptides from three different regions of IL-13RA2 with 100% sequence identity between human and canine receptors were used as immunogens for generation of monoclonal antibodies. Recombinant canine mutant IL-13 (canIL-13.E13K and canIL-13.E13K based cytotoxin were also produced. The antibodies were examined for their immunoreactivities in western blots, immunohistochemistry, immunofluorescence and cell binding assays using human and canine tumor specimen sections, tissue lysates and established cell lines; the cytotoxin was tested for specific cell killing. Several isolated MAbs were immunoreactive to IL-13RA2 in western blots of cell and tissue lysates from glioblastomas from both human and canine patients. Human and canine astrocytomas and oligodendrogliomas were also positive for IL-13RA2 to various degrees. Interestingly, both human and canine meningiomas also exhibited strong reactivity. Normal human and canine brain samples were virtually negative for IL-13RA2 using the newly generated MAbs. MAb 1E10B9 uniquely worked on tissue specimens and western blots, bound live cells and was internalized in GBM cells over-expressing IL-13RA2. The canIL-13.E13K cytotoxin was very potent and specific in killing canine GBM cell lines. Thus, we have obtained several monoclonal antibodies against IL-13RA2 cross-reacting with human and canine receptors. In addition to GBM, other brain tumors, such as high grade oligodendrogliomas, meningiomas and canine choroid plexus papillomas, appear to express the receptor at high levels

  1. A method for the determination of carbon 13 content in glucose and glycerol of blood plasma; Methode pour la determination de la teneur en carbone 13 du glucose et du glycerol dans les plasmas sanguins

    Energy Technology Data Exchange (ETDEWEB)

    Koziet, J. [Centre de Recherche Pernod-Ricard, 94 - Creteil (France)

    1994-12-31

    The coupled gaseous chromatography and isotope ratio mass spectrometry approach was first validated on beet and maize glucose and glycerol aqueous solutions containing variable carbon 13 content. Then human plasma was used to prepare samples where glucose and glycerol were labelled with small amounts of (1.3-{sup 13}C{sub 2})-glycerol and D-(U{sup 13}-C{sub 6})-glucose. The samples are then de-proteinized with acetone before lyophilization and acetylation in order to be able to measure them in the form of acetates. Carbon 13 content evaluation should then take into account the exogenous carbons from the acetyl radicals. This method appears well adapted to the simultaneous metabolic monitoring of glycerol and glucose in the blood plasma. 1 fig., 3 tabs., 5 refs.

  2. Enhancing the Accuracy of Carbonate δ18O and δ13C Measurements by SIMS

    Science.gov (United States)

    Orland, I. J.; Kozdon, R.; Linzmeier, B.; Wycech, J.; Sliwinski, M.; Kitajima, K.; Kita, N.; Valley, J. W.

    2015-12-01

    The precision and accuracy of carbonate δ18O & δ13C analysis by multicollector SIMS is well established if standards match samples in structure and major/minor element chemistry. However, low-T- and bio-carbonates used to construct paleoclimate archives can include complex internal structures and some samples analyzed at WiscSIMS (and other SIMS labs) have a consistent, sample-dependent offset between average SIMS δ18O measurements and bulk δ18O analyses by phosphoric-acid digestion. The offset is typically hydrogen peroxide), for which there is no agreed procedure in conventional bulk analyses. For SIMS analyses, pre-treatments had varied influence on the δ18O value, [16O1H], the concentration of "organic markers" like 12C14N and 31P, and mineralogy (of aragonite samples).

  3. Carbon-13 variations in fluids from the Cerro Prieto geothermal system

    Energy Technology Data Exchange (ETDEWEB)

    Janik, C.J.; Nehring, N.L.; Huebner, M.A.; Truesdell, A.H.

    1982-08-10

    The carbon isotope compositions of CO/sub 2/ in steam from Cerro Prieto production well have been measured for 1977, 1979, and 1982. Variations in the delta/sup 13/C values are caused by production-related changes in the chemical and physical parameters of the geothermal system. In 1977, most CO/sub 2/ in the reservoir was isotopically light (delta/sup 13/C = -6.4 +/- 0.4). Heavier CO/sub 2/ was produced from wells in the center of the field (M5,M26,M27) due to deposition of isotopically light calcite caused by near-well boiling. In 1979 nearly all well showed relatively heavy CO/sub 2/, probably due to expansion of aquifer boiling and calcite precipitation. In 1982, many wells in the central part of the field were shut in. The amount of drawndown decreased and as temperatures and pressures near the wells increased, the boiling zones collapsed. The CO/sub 2/ in the fluid then exchanged with the precipitated calcite and became isotopically lighter. The sensitivity of carbon isotopes to calcite precipitations caused by aquifer boiling and to reequilibration with this deposited calcite upon decrease of boiling suggests use as an indicator of these aquifer processes. Surficial CO/sub 2/ of thermal origin was collected in 1981. Generally, the carbon-13 contents were close to CO/sub 2/ from production wells except for high-temperature mud pots and fumaroles containing isotopically light CO/sub 2/ derived from near surface alteration of organic matter.

  4. Influence of manganese and nickel on properties of low-carbon steels with 13% Cr

    International Nuclear Information System (INIS)

    Studied is the influence of manganese and nickel on mechanical properties and resistance-to-corrosion of the 13% content chromium steels containing 0.1-0.2%C. It is shown that manganese introduction results is the increase of strength characteristics of hardened steels because of delta-ferrite formation suppresion and solid solution strengthening. The delayed cooling during hardening permits to increase ductility and impact strength. Low-carbon 13% content chromium steels alloyed with nickel, molybdenum and aluminium have high heat resistance at temperatures up to 500 deg C due to the precipitation of intermetallics atlading. Chrome-manganese and chrome-nickel steels have a high resistance-to-corrosion in the hardened state in the neutral and weak-acid media

  5. Measurement of soil carbon oxidation state and oxidative ratio by 13C nuclear magnetic resonance

    Science.gov (United States)

    Hockaday, W.C.; Masiello, C.A.; Randerson, J.T.; Smernik, R.J.; Baldock, J.A.; Chadwick, O.A.; Harden, J.W.

    2009-01-01

    The oxidative ratio (OR) of the net ecosystem carbon balance is the ratio of net O2 and CO2 fluxes resulting from photosynthesis, respiration, decomposition, and other lateral and vertical carbon flows. The OR of the terrestrial biosphere must be well characterized to accurately estimate the terrestrial CO2 sink using atmospheric measurements of changing O2 and CO2 levels. To estimate the OR of the terrestrial biosphere, measurements are needed of changes in the OR of aboveground and belowground carbon pools associated with decadal timescale disturbances (e.g., land use change and fire). The OR of aboveground pools can be measured using conventional approaches including elemental analysis. However, measuring the OR of soil carbon pools is technically challenging, and few soil OR data are available. In this paper we test three solid-state nuclear magnetic resonance (NMR) techniques for measuring soil OR, all based on measurements of the closely related parameter, organic carbon oxidation state (Cox). Two of the three techniques make use of a molecular mixing model which converts NMR spectra into concentrations of a standard suite of biological molecules of known C ox. The third technique assigns Cox values to each peak in the NMR spectrum. We assess error associated with each technique using pure chemical compounds and plant biomass standards whose Cox and OR values can be directly measured by elemental analyses. The most accurate technique, direct polarization solid-state 13C NMR with the molecular mixing model, agrees with elemental analyses to ??0.036 Cox units (??0.009 OR units). Using this technique, we show a large natural variability in soil Cox and OR values. Soil Cox values have a mean of -0.26 and a range from -0.45 to 0.30, corresponding to OR values of 1.08 ?? 0.06 and a range from 0.96 to 1.22. We also estimate the OR of the carbon flux from a boreal forest fire. Analysis of soils from nearby intact soil profiles imply that soil carbon losses associated

  6. Apelin-13 as a novel target for intervention in secondary injury after traumatic brain injury.

    Science.gov (United States)

    Bao, Hai-Jun; Qiu, Hai-Yang; Kuai, Jin-Xia; Song, Cheng-Jie; Wang, Shao-Xian; Wang, Chao-Qun; Peng, Hua-Bin; Han, Wen-Can; Wu, Yong-Ping

    2016-07-01

    The adipocytokine, apelin-13, is an abundantly expressed peptide in the nervous system. Apelin-13 protects the brain against ischemia/reperfusion injury and attenuates traumatic brain injury by suppressing autophagy. However, secondary apelin-13 effects on traumatic brain injury-induced neural cell death and blood-brain barrier integrity are still not clear. Here, we found that apelin-13 significantly decreases cerebral water content, mitigates blood-brain barrier destruction, reduces aquaporin-4 expression, diminishes caspase-3 and Bax expression in the cerebral cortex and hippocampus, and reduces apoptosis. These results show that apelin-13 attenuates secondary injury after traumatic brain injury and exerts a neuroprotective effect. PMID:27630697

  7. Experimental validation of environmental controls on the δ13C of Arctica islandica (ocean quahog) shell carbonate

    Science.gov (United States)

    Beirne, Erin C.; Wanamaker, Alan D.; Feindel, Scott C.

    2012-05-01

    The marine bivalve species, Arctica islandica, was reared under experimental conditions for 29 weeks in the Gulf of Maine in order to determine the relationship between the carbon isotope composition of shell carbonate13CS) and ambient seawater dissolved inorganic carbon13CDIC), as well as to approximate the metabolic contribution (CM) to shell material. Three experimental environments were compared: two flow-through tanks (one at ambient seawater conditions, one with a supplemental food source) and an in situ cage. Each environment contained 50 juveniles and 30 adults. Both juvenile (2-3 years) and adult (19-64 years) specimens displayed average percent CM of less than or equal to 10% when using three different proxies of respired carbon: digestive gland, adductor muscle and sediment. Hence, the primary control on δ13CS values is ambient DIC. The relationship between δ13CDIC and δ13CS for 114 individuals used in the study was: δ13C=δ13C-1.0‰(±0.3‰) No ontogenetic effect on δ13CS was observed, and growth rates did not generally impact δ13CS values. Based on the results of this study, shell material derived from the long-lived ocean quahog (A. islandica) constitutes a viable proxy for paleo-DIC from the extratropical Atlantic Ocean.

  8. A quartz-lined carbon-11 target: striving for increased yield and specific activity

    DEFF Research Database (Denmark)

    Koziorowski, Jacek; Larsen, Peter; Gillings, Nic

    2010-01-01

    The increased demand for high specific radioactivity neuroreceptor ligands for positron emission tomography (PET) requires the production of high specific radioactivity carbon-11 in high yields. We have attempted to address this issue with the development of a new quartz-lined aluminium target fo...

  9. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING

    Energy Technology Data Exchange (ETDEWEB)

    Stephen C. Ruppel

    2005-02-01

    Despite declining production rates, existing reservoirs in the US contain large quantities of remaining oil and gas that constitute a huge target for improved diagnosis and imaging of reservoir properties. The resource target is especially large in carbonate reservoirs, where conventional data and methodologies are normally insufficient to resolve critical scales of reservoir heterogeneity. The objectives of the research described in this report were to develop and test such methodologies for improved imaging, measurement, modeling, and prediction of reservoir properties in carbonate hydrocarbon reservoirs. The focus of the study is the Permian-age Fullerton Clear Fork reservoir of the Permian Basin of West Texas. This reservoir is an especially appropriate choice considering (a) the Permian Basin is the largest oil-bearing basin in the US, and (b) as a play, Clear Fork reservoirs have exhibited the lowest recovery efficiencies of all carbonate reservoirs in the Permian Basin.

  10. Characterisation of Diamond-Like Carbon (DLC) laser targets by Raman spectroscopy

    Science.gov (United States)

    Haddock, D.; Parker, T.; Spindloe, C.; Tolley, M.

    2016-04-01

    The search for target materials suitable for High Power Laser Experiments at ultralow thicknesses (below ten nanometres) is ongoing. Diamond-Like Carbon is investigated as an answer for a low-Z material that can survive target chamber pump-down and laser prepulse. DLC was produced using Plasma-Enhanced Chemical Vapour Deposition, using with varying gas flow mixtures of argon and methane. The methane plasma deposits amorphous carbon onto the substrate and the argon plasma re-sputters the weakly bonded carbon leaving a high proportion of diamond-like bonding. Bonding natures were probed using Raman spectroscopy; analysis of the resulting spectrum showed that flow rates of 40sccm/60sccm methane to argon produced DLC films with a diamond-like (sp 3) content of ∼20%. Increasing the methane gas flow decreased this value to less than 5%. DLC foils were processed into laser targets by method of float off; using a sodium chloride release layer and lowering into water, this was then lifted onto an array of apertures allowing for laser irradiation of the material with no backing. DLC with 20% sp 3 content showed superior yield when compared to other materials such as metals and some plastics of the same thickness, with ∼70% of the target positions surviving the float off procedure at <10nm. As a result of this work DLC targets have been available for a number of experiments at the Central Laser Facility.

  11. TCDD dysregulation of 13 AHR-target genes in rat liver

    Energy Technology Data Exchange (ETDEWEB)

    Watson, John D., E-mail: john.watson@oicr.on.ca [Ontario Institute for Cancer Research, Department of Informatics and Bio-computing Program, Toronto (Canada); Prokopec, Stephenie D., E-mail: stephenie.prokopec@oicr.on.ca [Ontario Institute for Cancer Research, Department of Informatics and Bio-computing Program, Toronto (Canada); Smith, Ashley B., E-mail: ashleyblaines@gmail.com [Ontario Institute for Cancer Research, Department of Informatics and Bio-computing Program, Toronto (Canada); Okey, Allan B., E-mail: allan.okey@utoronto.ca [Department of Pharmacology and Toxicology, University of Toronto, Toronto (Canada); Pohjanvirta, Raimo, E-mail: raimo.pohjanvirta@helsinki.fi [Laboratory of Toxicology, National Institute for Health and Welfare, Kuopio (Finland); Department of Food Hygiene and Environmental Health, University of Helsinki, Helsinki (Finland); Boutros, Paul C., E-mail: paul.boutros@oicr.on.ca [Ontario Institute for Cancer Research, Department of Informatics and Bio-computing Program, Toronto (Canada); Department of Pharmacology and Toxicology, University of Toronto, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada)

    2014-02-01

    Despite several decades of research, the complete mechanism by which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other xenobiotic agonists of the aryl hydrocarbon receptor (AHR) cause toxicity remains unclear. While it has been shown that the AHR is required for all major manifestations of toxicity, the specific downstream changes involved in the development of toxic phenotypes remain unknown. Here we examine a panel of 13 genes that are AHR-regulated in many species and tissues. We profiled their hepatic mRNA abundances in two rat strains with very different sensitivities to TCDD: the TCDD-sensitive Long–Evans (Turku/AB; L–E) and the TCDD-resistant Han/Wistar (Kuopio; H/W). We evaluated doses ranging from 0 to 3000 μg/kg at 19 h after TCDD exposure and time points ranging from 1.5 to 384 h after exposure to 100 μg/kg TCDD. Twelve of 13 genes responded to TCDD in at least one strain, and seven of these showed statistically significant inter-strain differences in the time course analysis (Aldh3a1, Cyp1a2, Cyp1b1, Cyp2a1, Fmo1, Nfe2l2 and Nqo1). Cyp2s1 did not respond to TCDD in either rat strain. Five genes exhibited biphasic responses to TCDD insult (Ahrr, Aldh3a1, Cyp1b1, Nfe2l2 and Nqo1), suggesting a secondary event, such as association with additional transcriptional modulators. Of the 12 genes that responded to TCDD during the dose–response analysis, none had an ED{sub 50} equivalent to that of Cyp1a1, the most sensitive gene in this study, while nine genes responded to doses at least 10–100 fold higher, in at least one strain (Ahrr (L–E), Aldh3a1 (both), Cyp1a2 (both), Cyp1b1 (both), Cyp2a1 (L–E), Inmt (both), Nfe2l2 (L–E), Nqo1 (L–E) and Tiparp (both)). These data shed new light on the association of the AHR target genes with TCDD toxicity, and in particular the seven genes exhibiting strain-specific differences represent strong candidate mediators of Type-II toxicities. - Highlights: • NanoString measured hepatic mRNA molecules

  12. Long-term steady state 13C labelling to investigate carbon turnover in plant soil systems

    Directory of Open Access Journals (Sweden)

    R. Falcimagne

    2007-03-01

    Full Text Available We have set up a facility allowing steady state 13CO2 labeling of short stature vegetation (12 m2 for several years. 13C labelling is obtained by scrubbing the CO2 from outdoors air with a self-regenerating molecular sieve and by replacing it with 13C depleted (−34.7±0.03‰ fossil-fuel derived CO2 The facility, which comprises 16 replicate mesocosms, allows tracing the fate of photosynthetic carbon in plant-soil systems in natural light and at outdoors temperature. This method was applied during 2 yrs to temperate grassland monoliths (0.5×0.5×0.4 m sampled in a long term grazing experiment. During daytime, the canopy enclosure in each mesocosm was supplied in an open flow (0.67–0.88 volume per minute with modified air (43% scrubbed air and 57% cooled and humidified ambient air at mean CO2 concentration of 425 µmol mol−1 and δ13C of −21.5±0.27‰. Above and belowground CO2 fluxes were continuously monitored. The difference in δ13C between the CO2 at the outlet and at the inlet of each canopy enclosure was not significant (−0.35±0.39‰. Due to mixing with outdoors air, the CO2 concentration at enclosure inlet followed a seasonal cycle, often found in urban areas, where δ13C of CO2 is lower in winter than in summer. Mature C3 grass leaves were sampled monthly in each mesocosm, as well as leave from pot-grown control C4 (Paspalum dilatatum. The mean δ13C of fully labelled C3 and C4 leaves reached −41.4±0.67 and −28.7±0.39‰ respectively. On average, the labelling reduced by 12.7‰ the δ13C of C3 grass leaves. The isotope mass balance technique was used to calculate the fraction of "new" C in the soil organic matter (SOM above 0.2 mm. A first order exponential decay model fitted to "old" C data showed that reducing aboveground disturbance by cutting increased from 22 to 31 months the mean residence time of belowground organic C (>0.2 mm in the top soil.

  13. Is China's carbon reduction target allocation reasonable? An analysis based on carbon intensity convergence

    OpenAIRE

    Yu Hao; Hua Liao; Yi-Ming Wei

    2014-01-01

    To curb CO2 emissions, the Chinese government has announced ambitious goals to reduce the CO2 intensity of GDP, and the total target has been allocated to all Chinese provinces during the twelfth "Five-year Plan" period (2011-2015). Although setting the target allocation plan is an efficient way to achieve this goal, some key questions, including how the plan is designed, remained unanswered. From an economic perspective, this requires us to test for the existence of convergence in the CO2 in...

  14. Nanobiotechnology meets plant cell biology: Carbon nanotubes as organelle targeting nanocarriers

    KAUST Repository

    Bayoumi, Maged Fouad

    2013-01-01

    For years, nanotechnology has shown great promise in the fields of biomedical and biotechnological sciences and medical research. In this review, we demonstrate its versatility and applicability in plant cell biology studies. Specifically, we discuss the ability of functionalized carbon nanotubes to penetrate the plant cell wall, target specific organelles, probe protein-carrier activity and induce organelle recycling in plant cells. We also, shed light on prospective applications of carbon nanomaterials in cell biology and plant cell transformation. © 2013 The Royal Society of Chemistry.

  15. Synthesis of deleobuvir, a potent hepatitis C virus polymerase inhibitor, and its major metabolites labeled with carbon-13 and carbon-14.

    Science.gov (United States)

    Latli, Bachir; Hrapchak, Matt; Chevliakov, Maxim; Li, Guisheng; Campbell, Scot; Busacca, Carl A; Senanayake, Chris H

    2015-05-30

    Deleobuvir, (2E)-3-(2-{1-[2-(5-bromopyrimidin-2-yl)-3-cyclopentyl-1-methyl-1H-indole-6-carboxamido]cyclobutyl}-1-methyl-1H-benzimidazol-6-yl)prop-2-enoic acid (1), is a non-nucleoside, potent, and selective inhibitor of hepatitis C virus NS5B polymerase. Herein, we describe the detailed synthesis of this compound labeled with carbon-13 and carbon-14. The synthesis of its three major metabolites, namely, the reduced double bond metabolite (2) and the acyl glucuronide derivatives of (1) and (2), is also reported. Aniline-(13) C6 was the starting material to prepare butyl (E)-3-(3-methylamino-4-nitrophenyl-(13) C6 )acrylate [(13) C6 ]-(11) in six steps. This intermediate was then used to obtain [(13) C6 ]-(1) and [(13) C6 ]-(2) in five and four more steps, respectively. For the radioactive synthesis, potassium cyanide-(14) C was used to prepare 1-cylobutylaminoacid [(14) C]-(23) via Buchrer-Bergs reaction. The carbonyl chloride of this acid was then used to access both [(14) C]-(1) and [(14) C]-(2) in four steps. The acyl glucuronide derivatives [(13) C6 ]-(3), [(13) C6 ]-(4) and [(14) C]-(3) were synthesized in three steps from the acids [(13) C6 ]-(1), [(13) C6 ]-(2) and [(14) C]-(1) using known procedures. PMID:25964148

  16. Tandem CAR T cells targeting HER2 and IL13Rα2 mitigate tumor antigen escape.

    Science.gov (United States)

    Hegde, Meenakshi; Mukherjee, Malini; Grada, Zakaria; Pignata, Antonella; Landi, Daniel; Navai, Shoba A; Wakefield, Amanda; Fousek, Kristen; Bielamowicz, Kevin; Chow, Kevin K H; Brawley, Vita S; Byrd, Tiara T; Krebs, Simone; Gottschalk, Stephen; Wels, Winfried S; Baker, Matthew L; Dotti, Gianpietro; Mamonkin, Maksim; Brenner, Malcolm K; Orange, Jordan S; Ahmed, Nabil

    2016-08-01

    In preclinical models of glioblastoma, antigen escape variants can lead to tumor recurrence after treatment with CAR T cells that are redirected to single tumor antigens. Given the heterogeneous expression of antigens on glioblastomas, we hypothesized that a bispecific CAR molecule would mitigate antigen escape and improve the antitumor activity of T cells. Here, we created a CAR that joins a HER2-binding scFv and an IL13Rα2-binding IL-13 mutein to make a tandem CAR exodomain (TanCAR) and a CD28.ζ endodomain. We determined that patient TanCAR T cells showed distinct binding to HER2 or IL13Rα2 and had the capability to lyse autologous glioblastoma. TanCAR T cells exhibited activation dynamics that were comparable to those of single CAR T cells upon encounter of HER2 or IL13Rα2. We observed that TanCARs engaged HER2 and IL13Rα2 simultaneously by inducing HER2-IL13Rα2 heterodimers, which promoted superadditive T cell activation when both antigens were encountered concurrently. TanCAR T cell activity was more sustained but not more exhaustible than that of T cells that coexpressed a HER2 CAR and an IL13Rα2 CAR, T cells with a unispecific CAR, or a pooled product. In a murine glioblastoma model, TanCAR T cells mitigated antigen escape, displayed enhanced antitumor efficacy, and improved animal survival. Thus, TanCAR T cells show therapeutic potential to improve glioblastoma control by coengaging HER2 and IL13Rα2 in an augmented, bivalent immune synapse that enhances T cell functionality and reduces antigen escape.

  17. Tandem CAR T cells targeting HER2 and IL13Rα2 mitigate tumor antigen escape.

    Science.gov (United States)

    Hegde, Meenakshi; Mukherjee, Malini; Grada, Zakaria; Pignata, Antonella; Landi, Daniel; Navai, Shoba A; Wakefield, Amanda; Fousek, Kristen; Bielamowicz, Kevin; Chow, Kevin K H; Brawley, Vita S; Byrd, Tiara T; Krebs, Simone; Gottschalk, Stephen; Wels, Winfried S; Baker, Matthew L; Dotti, Gianpietro; Mamonkin, Maksim; Brenner, Malcolm K; Orange, Jordan S; Ahmed, Nabil

    2016-08-01

    In preclinical models of glioblastoma, antigen escape variants can lead to tumor recurrence after treatment with CAR T cells that are redirected to single tumor antigens. Given the heterogeneous expression of antigens on glioblastomas, we hypothesized that a bispecific CAR molecule would mitigate antigen escape and improve the antitumor activity of T cells. Here, we created a CAR that joins a HER2-binding scFv and an IL13Rα2-binding IL-13 mutein to make a tandem CAR exodomain (TanCAR) and a CD28.ζ endodomain. We determined that patient TanCAR T cells showed distinct binding to HER2 or IL13Rα2 and had the capability to lyse autologous glioblastoma. TanCAR T cells exhibited activation dynamics that were comparable to those of single CAR T cells upon encounter of HER2 or IL13Rα2. We observed that TanCARs engaged HER2 and IL13Rα2 simultaneously by inducing HER2-IL13Rα2 heterodimers, which promoted superadditive T cell activation when both antigens were encountered concurrently. TanCAR T cell activity was more sustained but not more exhaustible than that of T cells that coexpressed a HER2 CAR and an IL13Rα2 CAR, T cells with a unispecific CAR, or a pooled product. In a murine glioblastoma model, TanCAR T cells mitigated antigen escape, displayed enhanced antitumor efficacy, and improved animal survival. Thus, TanCAR T cells show therapeutic potential to improve glioblastoma control by coengaging HER2 and IL13Rα2 in an augmented, bivalent immune synapse that enhances T cell functionality and reduces antigen escape. PMID:27427982

  18. Rapid uplift of the Altiplano revealed through 13C-18O bonds in paleosol carbonates.

    Science.gov (United States)

    Ghosh, Prosenjit; Garzione, Carmala N; Eiler, John M

    2006-01-27

    The elevation of Earth's surface is among the most difficult environmental variables to reconstruct from the geological record. Here we describe an approach to paleoaltimetry based on independent and simultaneous determinations of soil temperatures and the oxygen isotope compositions of soil waters, constrained by measurements of abundances of 13C-18O bonds in soil carbonates. We use this approach to show that the Altiplano plateau in the Bolivian Andes rose at an average rate of 1.03 +/- 0.12 millimeters per year between approximately 10.3 and approximately 6.7 million years ago. This rate is consistent with the removal of dense lower crust and/or lithospheric mantle as the cause of elevation gain.

  19. Investigation on biological properties of tacrolimus-loaded poly(1,3-trimethylene carbonate) in vitro

    International Nuclear Information System (INIS)

    The drug-eluting stents have been regarded as a milestone in inhibiting the restenosis of coronary arteries. However, adverse reactions caused by bare-metal stents and non-biodegradable polymer coatings may result in some clinical problems. In this study, a new tacrolimus-eluting stent coated with biodegradable poly(1,3-trimethylene carbonate) (PTMC) is developed. The structures are characterized by Fourier transform infrared (FTIR) analysis, and the wettability is measured by contact angle assay. The biological behaviors are evaluated by the in vitro platelets adhesion test, APTT test, the human umbilical cord artery smooth muscle cells (HUCASMCs), 4',6-diamidine-2-phenylindole (DAPI) and actin immunofluorescence staining, MTT colorimetric assay. These results show that after blending tacrolimus into PTMC, the anticoagulant behavior is improved, and the adhesion and proliferation of HUCASMCs on samples are inhibited. This work aims to find one kind of surface erosion biodegradable polymers that can be applied as drug-eluting stent coatings.

  20. Investigation on biological properties of tacrolimus-loaded poly(1,3-trimethylene carbonate) in vitro

    Science.gov (United States)

    Hou, Ruixia; Wu, Leigang; Wang, Jin; Huang, Nan

    2010-06-01

    The drug-eluting stents have been regarded as a milestone in inhibiting the restenosis of coronary arteries. However, adverse reactions caused by bare-metal stents and non-biodegradable polymer coatings may result in some clinical problems. In this study, a new tacrolimus-eluting stent coated with biodegradable poly(1,3-trimethylene carbonate) (PTMC) is developed. The structures are characterized by Fourier transform infrared (FTIR) analysis, and the wettability is measured by contact angle assay. The biological behaviors are evaluated by the in vitro platelets adhesion test, APTT test, the human umbilical cord artery smooth muscle cells (HUCASMCs), 4',6-diamidine-2-phenylindole (DAPI) and actin immunofluorescence staining, MTT colorimetric assay. These results show that after blending tacrolimus into PTMC, the anticoagulant behavior is improved, and the adhesion and proliferation of HUCASMCs on samples are inhibited. This work aims to find one kind of surface erosion biodegradable polymers that can be applied as drug-eluting stent coatings.

  1. Dissolved inorganic carbon (DIC) and its δ13C in the Ganga (Hooghly) River estuary, India: Evidence of DIC generation via organic carbon degradation and carbonate dissolution

    Science.gov (United States)

    Samanta, Saumik; Dalai, Tarun K.; Pattanaik, Jitendra K.; Rai, Santosh K.; Mazumdar, Aninda

    2015-09-01

    In this study, we present comprehensive data on dissolved Ca, dissolved inorganic carbon (DIC) and its carbon isotope composition (δ13CDIC) of (i) the Ganga (Hooghly) River estuary water sampled during six seasons of contrasting water discharge over 2 years (2012 and 2013), (ii) shallow groundwater from areas adjacent to the estuary and (iii) industrial effluent water and urban wastewater draining into the estuary. Mass balance calculations indicate that processes other than the conservative mixing of seawater and river water are needed to explain the measured DIC and δ13CDIC. Results of mixing calculations in conjunction with the estimated undersaturated levels of dissolved O2 suggest that biological respiration and organic carbon degradation dominate over biological production in the estuary. An important outcome of this study is that a significant amount of DIC and dissolved Ca is produced within the estuary at salinity ⩾10, particularly during the monsoon period. Based on consideration of mass balance and a strong positive correlation observed between the "excess" DIC and "excess" Ca, we contend that the dominant source of DIC generated within the estuary is carbonate dissolution that is inferred to be operating in conjunction with degradation of organic carbon. Calculations show that groundwater cannot account for the observed "excess" Ca in the high salinity zone. Estimated DIC contributions from anthropogenic activity are minor, and they constitute ca. 2-3% of the river water DIC concentrations. The estimated annual DIC flux from the estuary to the Bay of Bengal is ca. (3-4) × 1012 g, of which ca. 40-50% is generated within the estuary. The monsoon periods account for the majority (ca. 70%) of the annual DIC generation in the estuary. The annual DIC flux from the Hooghly estuary accounts for ca. 1% of the global river DIC flux to the oceans. This is disproportionately higher than the water contribution from the Hooghly River to the oceans, which

  2. Renovação do carbono-13 em figueiras 'Roxo de Valinhos' Carbon-13 turnover in fig trees 'Roxo de Valinhos'

    Directory of Open Access Journals (Sweden)

    Andréa Carvalho da Silva

    2011-06-01

    Full Text Available O objetivo do trabalho foi determinar a taxa de renova��ão do carbono-13 ("turnover", dos diferentes órgãos da figueira 'Roxo de Valinhos'. O experimento foi conduzido no pomar da Faculdade de Ciências Agronômicas, FCA/UNESP, Câmpus de Botucatu-SP. Determinou-se previamente, através das trocas gasosas com um medidor aberto portátil de fotossíntese, IRGA, a principal folha fotossinteticamente ativa. Essa folha foi colocada em uma câmara onde ocorreu a injeção do gás enriquecido. O tempo de enriquecimento da folha foi de 30 minutos. Os tratamentos foram constituídos por sete plantas de figueira, que foram retiradas do solo após: 6; 24; 48; 72; 120; 168 e 360 horas do enriquecimento com 13C, e suas partes seccionadas em: gema apical, folha jovem, folhas adultas (fotossinteticamente ativas, brotações laterais, frutos e ramo. Os resultados obtidos permitiram o estabelecimento da sequência de metabolização do carbono-13 nas partições estudadas: Folhas novas > Frutos > Brotações > Folhas Adultas > Gema Apical > Ramo > Folha marcada. Plantas de figueira 'Roxo de Valinhos' apresentam reciclagem do 13C de 24 horas e um tempo de meia-vida de duração do carbono-13 inferior a 11 horas.The aim of this study was to assess carbon-13 turnover in different organs of the fig tree cultivar 'Roxo de Valinhos'. The experiment was carried out in an orchard at School of Agronomical Sciences, FCA/UNESP, Botucatu Campus, São Paulo State, Brazil. The main photosynthetically active leaf was previously determined based on gas exchanges by means of an open portable photosynthesis system, IRGA. That leaf was placed in a chamber where the enriched gas injection occurred. The leaf enrichment time was 30 minutes. Treatments were constituted of seven fig trees harvested of soil after: 6; 24; 48; 72; 120; 168 and 360 hours of enrichment using 13C, and their parts were sectioned into: apical bud, young leaves, adult leaves (photosynthetically active

  3. An Empirical Assessment of the Risk of Carbon Leakage in Poland - Working Paper No. 08/13,

    International Nuclear Information System (INIS)

    Poland is a particularly carbon intensive economy. This has created concern that it may be particularly exposed to carbon leakage. However, there is an absence of robust and transparent empirical research on carbon leakage risks in Poland. This study aims at filling this gap by assessing the impact of EU climate policy, in particular the EU Emissions Trading Scheme, on Polish industry. With no mitigating measures, a small number of Polish industrial sectors would face significant carbon costs. However, with free allocation, banked surplus allowances and a carbon price of euros 30/ton, only one sector would face direct carbon costs in excess of 5% of operating profits. Three sectors face direct carbon costs in the order of 1-3% of operating profits; three face no direct carbon costs. With direct compensation for indirect carbon costs (electricity price increases), the two most affected sectors would face indirect costs of 3.5 to 5.5% of gross value added with a carbon price of euros 30/ ton. The vast majority of Poland's trade in energy intensive sectors occurs within the EU. It is important to maintain a harmonized climate policy to avoid internal market distortions. There is thus a negligible risk of carbon leakage in Poland under current policy. The mitigating measures in the EU Directive remove the vast majority of direct and indirect carbon costs for Polish industry. EU climate policy can be made more stringent without inducing risks of significant carbon leakage. The current benchmarking system appears to be reasonably effective at not structurally disadvantaging less carbon efficient Member States like Poland. And it is vital to maintaining a harmonized climate policy. Finding a harmonized way to address indirect carbon costs may unlock Polish support for future policy. (authors)

  4. Carbon-13 and oxygen-18 kinetic isotope effects on methanolysis of p-nitrostyrene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Jacober, S.P.; Hanzlik, R.P.

    1986-04-02

    Kinetic isotope effects for the acid- and base-catalyzed methanolysis of (epoxide-/sup 18/O)- and (8-/sup 13/C)-p-nitrostyrene oxide have been measured at 30.0/sup 0/. In acid 94.7% of the reaction occurs at the benzylic carbon, while in base 83.5% occurs at the primary carbon (C(8)). In base the isotope effects kappa/sub 16//kappa/sub 1/( and kappa/sub 1/''/kappa /sub 1/number were 1.035 +/- 0.013 and 1.082 +/- 0.012, while in acid they were 1.012 +/- 0.011 and 0.995 +/- 0.012, respectively. These data complement previously determined deuterium isotope effects for the reaction in base. They suggest a late transition state in base with considerable ring opening via an S/sub N/2 mechanism. However, in acid, the data suggest a somewhat earlier transition state with less ring opening and weaker bonding to the nucleophile than in base.

  5. Advances in cancer therapy through the use of carbon nanotube-mediated targeted hyperthermia

    Directory of Open Access Journals (Sweden)

    Iancu C

    2011-08-01

    Full Text Available Cornel Iancu, Lucian Mocan3rd Surgery Clinic, Department of Nanomedicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca, RomaniaAbstract: Carbon nanotubes (CNTs are emerging versatile tools in nanomedicine applications, particularly in the field of cancer targeting. Due to diverse surface chemistry and unique thermal properties, CNTs can act as strong optical absorbers in near infrared light where biological systems prove to be highly transparent. The process of laser-mediated ablation of cancer cells marked with biofunctionalized CNTs is frequently termed “nanophotothermolysis.” This paper illustrates the potential of engineered CNTs as laser-activated photothermal agents for the selective nanophotothermolysis of cancer cells.Keywords: carbon nanotubes, cancer targeting, functionalization, optical excitation, cancer treatment

  6. Study of facing target sputtered diamond-like carbon overcoats for hard disk drive media

    Energy Technology Data Exchange (ETDEWEB)

    Seet, H.L., E-mail: SEET_Hang_Li@dsi.a-star.edu.sg [Data Storage Institute, A*STAR Agency for Science, Technology and Research, 5 Engineering Drive 1, 117608 (Singapore); Ng, K.K.; Chen, X.Y. [Data Storage Institute, A*STAR Agency for Science, Technology and Research, 5 Engineering Drive 1, 117608 (Singapore); Yang, P. [Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603 (Singapore); Shen, L. [Institute of Materials Research and Engineering, A*STAR Agency for Science, Technology and Research, 3 Research Link, 117602 (Singapore); Ji, R.; Ng, H.X.; Lim, C.B. [Data Storage Institute, A*STAR Agency for Science, Technology and Research, 5 Engineering Drive 1, 117608 (Singapore)

    2015-07-01

    The demand for higher areal density in the hard disk drive industry has fuelled extensive research efforts and focuses on magnetic spacing reduction. In the head–disk interface arena, one of the key focuses is to reduce the carbon overcoat thickness without compromising the overcoat protection performance. Thus, in the search for alternative methods to reduce the carbon overcoat thickness, the facing target sputtering (FTS) process for diamond-like carbon deposition has been investigated. The resulting properties have been presented in this paper, with comparison to conventional diamond-like carbon (DLC) layers by other processes such as chemical vapor deposition and reactive sputtering with nitrogen. X-ray reflectometry results showed that facing target sputtered DLC samples displayed significantly higher density, at 2.87 g/cm{sup 3}, as compared to hydrogenated and nitrogenated DLC samples. This was attributed to the higher sp{sup 3} content, as obtained by X-ray photoelectron spectroscopy measurements. As a result of the high sp{sup 3} content, hardness of the FTS deposited samples was higher than that of the hydrogenated and nitrogenated DLC samples. In addition, the surface energy of FTS samples was observed to be comparable, but lower, than that of nitrogenated DLC samples through contact angle measurements. Clearances comparable to that of conventional DLC samples were achieved and the sample disks were flyable. Wear performance tests also revealed more wear resistance for the FTS deposited DLC samples, but also higher head wear. - Highlights: • Facing target sputtered (FTS) diamond-like carbon (DLC) samples were studied. • FTS DLC samples possess higher density and hardness. • Surface conditions and flyability performances for FTS DLC samples were comparable. • Wear tests on FTS DLC samples showed lower media wear, but higher head wear.

  7. Fractional enrichment of proteins using [2-{sup 13}C]-glycerol as the carbon source facilitates measurement of excited state {sup 13}Cα chemical shifts with improved sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Ahlner, Alexandra; Andresen, Cecilia; Khan, Shahid N. [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden); Kay, Lewis E. [The University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry, One King’s College Circle (Canada); Lundström, Patrik, E-mail: patlu@ifm.liu.se [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden)

    2015-07-15

    A selective isotope labeling scheme based on the utilization of [2-{sup 13}C]-glycerol as the carbon source during protein overexpression has been evaluated for the measurement of excited state {sup 13}Cα chemical shifts using Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion (RD) experiments. As expected, the fractional incorporation of label at the Cα positions is increased two-fold relative to labeling schemes based on [2-{sup 13}C]-glucose, effectively doubling the sensitivity of NMR experiments. Applications to a binding reaction involving an SH3 domain from the protein Abp1p and a peptide from the protein Ark1p establish that accurate excited state {sup 13}Cα chemical shifts can be obtained from RD experiments, with errors on the order of 0.06 ppm for exchange rates ranging from 100 to 1000 s{sup −1}, despite the small fraction of {sup 13}Cα–{sup 13}Cβ spin-pairs that are present for many residue types. The labeling approach described here should thus be attractive for studies of exchanging systems using {sup 13}Cα spin probes.

  8. Targeting one carbon metabolism with an antimetabolite disrupts pyrimidine homeostasis and induces nucleotide overflow

    OpenAIRE

    Ser, Zheng; GAO, XIA; Johnson, Christelle; Mehrmohamadi, Mahya; Liu, Xiaojing; Li, SiQi; Locasale, Jason W.

    2016-01-01

    Anti-metabolite agents that affect nucleotide metabolism are frontline chemotherapy agents in several cancers and often successfully target one carbon metabolism. However, the precise mechanisms and resulting determinants of their therapeutic value are unknown. We show that 5-fluorouracil (5-FU), a commonly used anti-metabolite therapeutic with varying efficacy, induces specific alterations to nucleotide metabolism by disrupting pyrimidine homeostasis. An integrative metabolomics analysis of ...

  9. Characterisation of black carbon-rich samples by 13C solid-state nuclear magnetic resonance

    Science.gov (United States)

    Novotny, Etelvino H.; Hayes, Michael H. B.; Deazevedo, Eduardo R.; Bonagamba, Tito J.

    2006-09-01

    There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de Índio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. 13C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, 1H-13C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the π pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp—variable amplitude CP (VACP)—VACP/MAS pulse sequence, and composite π pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins.

  10. Characterisation of black carbon-rich samples by (13)C solid-state nuclear magnetic resonance.

    Science.gov (United States)

    Novotny, Etelvino H; Hayes, Michael H B; Deazevedo, Eduardo R; Bonagamba, Tito J

    2006-09-01

    There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de Indio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. (13)C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, (1)H-(13)C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the pi pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp--variable amplitude CP (VACP)--VACP/MAS pulse sequence, and composite pi pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins. PMID:16688435

  11. The use of natural abundance carbon-13 to identify and quantify sources of emitted carbon dioxide in a calcareous southern Ontario Luvisolic soil

    Science.gov (United States)

    Wilton, Meaghan

    Three studies Were conducted at the Elora Research Station (ERS) on a Luvisolic soil to investigate the soil inorganic carbon (SIC) and soil organic carbon (SOC) components contributing to the CO2 flux (FC) using natural 13C abundance. SIC contributed to the FC in intact soil incubations. Soil disruption exacerbated the release of CO2 from both pedogenic and lithogenic carbonates. Field and laboratory techniques to obtain the delta13C of respired CO2 (delta13CR) were compared. Short-term deployment of non flow-through non steady-state chambers and the use of the simple two-ended mass balance approach to derive delta 13CR were found acceptable to apply to the ERS site. The delta13CR from a corn field at ERS with a history of multiple C4 and C3 crop rotations was partitioned into SIC and SOC components using two approaches. Root respiration contributed 2% - 64% and carbonates contribute up to 20% to the FC.

  12. Influence of carbon on the giant magnetocaloric effect of LaFe11.7Si1.3

    Institute of Scientific and Technical Information of China (English)

    LI Junqin; LIU Fusheng; AO Weiqin; ZHUANG Yinghong; ZHOU Kaiwen

    2006-01-01

    The influences of carbon on phase formation, Curie temperature, and magnetic entropy change of the NaZn13-type LaFe11.7Si1.3 were investigated. Seven carbon-containing alloys, LaFe11.7Si1.3Cx with x = 0, 0.03, 0.06, 0.10, 0.20, 0.30, and 0.50, respectively, were prepared for this investigation. Experimental results show that addition of a small amount of carbon in LaFe11.7Si1.3 is favorable for the formation of the NaZn13-type structure of LaFe11.7Si1.3Cx. The lattice constant increases with C addition and x increases in the alloy because of the introduction of C as interstitial atoms. The Cu rie temperature of LaFe11.7Si1.3Cx increases from 194 K to 225 K as x increases from 0 to 0.5. Large magnetic entropy changes were observed in these carbon-hontaining alloys LaFe11.7Si1.3Cx because of their first-order structural/magnetic observed in the alloy with x = 0.06. The large magnetic-entropy changes corresponding to low magnetic field change, and the low cost of the material of LaFe11.7Si1.3Cx makes it a promising candidate to be used as magnetic refrigerants in the corresponding temperature range.

  13. Sulfuric acid as an agent of carbonate weathering constrained by δ13C DIC: Examples from Southwest China

    Science.gov (United States)

    Li, Si-Liang; Calmels, Damien; Han, Guilin; Gaillardet, Jérôme; Liu, Cong-Qiang

    2008-06-01

    Rock weathering by carbonic acid is thought to play an important role in the global carbon cycle because it can geologically sequestrate atmospheric CO 2. Current model of carbon cycle evolution usually assumes that carbonic acid is the major weathering agent and that other acids are not important. Here, we use carbon isotopic evidence and water chemistry of springs and rivers from the Beipanjiang River basin (Guizhou Province, Southwest China) to demonstrate that sulfuric acid is also an important agent of rock weathering. The δ13C of dissolved inorganic carbon (DIC) in the water samples ranges from - 13.1‰ to - 2.4‰, and correlates negatively to [HCO 3-]/([Ca 2+] + [Mg 2+]) ratios and positively to [SO 42-]/([Ca 2+] + [Mg 2+]) ratios. These relationships are interpreted as mixing diagrams between two reactions of carbonate weathering, using carbonic acid and sulfuric acid as a proton donor, respectively. Mixing proportions show that around 42% of the divalent cations in the spring water from Guizhou are originated from the interaction between carbonate minerals and sulfuric acid. It is shown that 40% of this sulfuric acid is derived from the atmosphere and has an anthropogenic origin. The remaining 60% are derived from the oxidative weathering of sulfide minerals in sedimentary rocks. Our results show the positive action of sulfuric acid on the chemical weathering of carbonate. Particularly, we show that sulfuric acid generated by coal combustion has increased by almost 20% the weathering rates of carbonate in Southwest China. This is a clear evidence that human activities are changing the weathering rates of rocks and demonstrates a negative feedback on the acidification of the ocean by greenhouse gases. Because of the involvement of sulfuric acid in weathering reactions, 63% of the alkalinity exported by rivers is derived from carbonate, instead of 50% when atmospheric CO 2 is the only acid involved in chemical weathering of carbonate. In the Guizhou

  14. Target-plane deposition of diamond-like carbon in pulsed laser ablation of graphite

    Energy Technology Data Exchange (ETDEWEB)

    Yap, S.S. [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia); Tou, T.Y. [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia)], E-mail: tytou@mmu.edu.my

    2007-10-15

    In pulsed Nd:YAG laser ablation of highly oriented pyrolytic graphite (HOPG) at 10{sup -6} Torr, diamond-like carbon (DLC) are deposited at laser wavelengths of 1064, 532, and 355 nm on substrates placed in the target-plane. These target-plane samples are found to contain varying sp{sup 3} content and composed of nanostructures of 40-200 nm in size depending on the laser wavelength and laser fluence. The material and origin of sp{sup 3} in the target-plane samples is closely correlated to that in the laser-modified HOPG surface layer, and hardly from the backward deposition of ablated carbon plume. The surface morphology of the target-plane samples shows the columnar growth and with a tendency for agglomeration between nanograins, in particular for long laser wavelength at 1064 nm. It is also proposed that DLC formation mechanism at the laser-ablated HOPG is possibly via the laser-induced subsurface melting and resolidification.

  15. Neutron-rich isotope production using a uranium carbide - carbon nanotubes SPES target prototype

    Energy Technology Data Exchange (ETDEWEB)

    Corradetti, S. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Universita di Padova, Dipartimento di Scienze Chimiche, Padova (Italy); Biasetto, L. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Universita di Padova, Dipartimento di Tecnica e Gestione dei Sistemi Industriali, Vicenza (Italy); Manzolaro, M.; Scarpa, D.; Andrighetto, A.; Prete, G. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Carturan, S. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Vasquez, J. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Universita di Padova, Dipartimento di Ingegneria dell' Informazione, Padova (Italy); Zanonato, P. [Universita di Padova, Dipartimento di Scienze Chimiche, Padova (Italy); Colombo, P. [Universita di Padova, Dipartimento di Ingegneria Industriale, Padova (Italy); Jost, C.U. [University of Tennessee, Department of Physics and Astronomy, Knoxville (United States); Stracener, D.W. [Oak Ridge National Laboratory, Physics Division, Oak Ridge (United States)

    2013-05-15

    The SPES (Selective Production of Exotic Species) project, under development at the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro (INFN-LNL), is a new-generation Isotope Separation On-Line (ISOL) facility for the production of radioactive ion beams by means of the proton-induced fission of uranium. In the framework of the research on the SPES target, seven uranium carbide discs, obtained by reacting uranium oxide with graphite and carbon nanotubes, were irradiated with protons at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL). In the following, the yields of several fission products obtained during the experiment are presented and discussed. The experimental results are then compared to those obtained using a standard uranium carbide target. The reported data highlights the capability of the new type of SPES target to produce and release isotopes of interest for the nuclear physics community. (orig.)

  16. Neutron-Rich Isotope Production Using a Uranium Carbide Carbon Nanotubes SPES Target Prototype

    Energy Technology Data Exchange (ETDEWEB)

    Corradetti, Stefano [ORNL; Biasetto, Lisa [INFN, Laboratori Nazionali di Legnaro, Italy; Manzolaro, Mattia [INFN, Laboratori Nazionali di Legnaro, Italy; Scarpa, Daniele [ORNL; Carturan, S. [INFN, Laboratori Nazionali di Legnaro, Italy; Andrighetto, Alberto [INFN, Laboratori Nazionali di Legnaro, Italy; Prete, Gianfranco [ORNL; Vasquez, Jose L [ORNL; Zanonato, P. [Dipartimento di Scienze Chimiche, Padova, Italy; Colombo, P. [Dipartimento di Ingegneria Meccanica, Padova, Italy; Jost, Carola [University of Tennessee, Knoxville (UTK); Stracener, Daniel W [ORNL

    2013-01-01

    The SPES (Selective Production of Exotic Species) project, under development at the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro (INFN-LNL), is a new-generation Isotope Separation On-Line (ISOL) facility for the production of radioactive ion beams by means of the proton-induced fission of uranium. In the framework of the research on the SPES target, seven uranium carbide discs, obtained by reacting uranium oxide with graphite and carbon nanotubes, were irradiated with protons at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL). In the following, the yields of several fission products obtained during the experiment are presented and discussed. The experimental results are then compared to those obtained using a standard uranium carbide target. The reported data highlights the capability of the new type of SPES target to produce and release isotopes of interest for the nuclear physics community.

  17. Properties of Diamond-Like Carbon Films Synthesized by Dual-Target Unbalanced Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    LIU Cui; LI Guo-Qing; GOU Wei; MU Zong-Xin; ZHANG Cheng-Wu

    2004-01-01

    @@ Smooth, dense and uniform diamond-like carbon films (DLC films) for industrial applications have successfully been prepared by dual-target unbalanced magnetron sputtering and the DLC characteristics of the films are confirmed by Raman spectra. It is found that the sputtering current of target plays an important role in the DLC film deposition. Deposition rate of 3.5μm/h is obtained by using the sputtering current of 30 A. The friction coefficient of the films is 0.2-0.225 measured by using a pin-on-disc microtribometer. The structure of the films tends to have a growth of sp3 bonds content at high sputtering current. The compressive residual stress in the films increases with the increasing sputtering current of the target.

  18. Neutron-rich isotope production using a uranium carbide - carbon nanotubes SPES target prototype

    Science.gov (United States)

    Corradetti, S.; Biasetto, L.; Manzolaro, M.; Scarpa, D.; Carturan, S.; Andrighetto, A.; Prete, G.; Vasquez, J.; Zanonato, P.; Colombo, P.; Jost, C. U.; Stracener, D. W.

    2013-05-01

    The SPES (Selective Production of Exotic Species) project, under development at the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro (INFN-LNL), is a new-generation Isotope Separation On-Line (ISOL) facility for the production of radioactive ion beams by means of the proton-induced fission of uranium. In the framework of the research on the SPES target, seven uranium carbide discs, obtained by reacting uranium oxide with graphite and carbon nanotubes, were irradiated with protons at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL). In the following, the yields of several fission products obtained during the experiment are presented and discussed. The experimental results are then compared to those obtained using a standard uranium carbide target. The reported data highlights the capability of the new type of SPES target to produce and release isotopes of interest for the nuclear physics community.

  19. Carbon emission reduction targeting through process integration and fuel switching with mathematical modeling

    International Nuclear Information System (INIS)

    Highlights: ► CO2 emissions reduction targeting for existing plant were categorized into three groups. ► Model for CO2 emissions reduction targeting via combination approach was developed. ► Effect of combination approach onto HEN area efficiency was discussed. ► Proposed execution strategy can avoid HEN area efficiency deterioration. -- Abstract: Carbon emission reduction targeting is an important and effective effort for industry to contribute in controlling greenhouse gases concentration in atmosphere. Graphical approach has been proposed for CO2 emissions reduction targeting via HEN retrofit and fuel switching. However, it involves potentially time consuming manual procedures and the quality of solutions produced greatly depends on designer’s experience and judgment. Besides, graphical approach hardly account for the cost factor during the design phase, thus potentially generate complex design. This paper introduces an MINLP model for simultaneous CO2 emissions reduction targeting via fuel switching and HEN retrofit. A sequential model execution was proposed along with the proposed model. The application of the model on a crude preheat train case study has demonstrated its workability to generate optimal solution for targeted CO2 emissions reduction at minimum payback period.

  20. Targeting Kv1.3 channels to reduce white matter pathology after traumatic brain injury.

    Science.gov (United States)

    Reeves, Thomas M; Trimmer, Patricia A; Colley, Beverly S; Phillips, Linda L

    2016-09-01

    Axonal injury is present in essentially all clinically significant cases of traumatic brain injury (TBI). While no effective treatment has been identified to date, experimental TBI models have shown promising axonal protection using immunosuppressants FK506 and Cyclosporine-A, with treatment benefits attributed to calcineurin inhibition or protection of mitochondrial function. However, growing evidence suggests neuroprotective efficacy of these compounds may also involve direct modulation of ion channels, and in particular Kv1.3. The present study tested whether blockade of Kv1.3 channels, using Clofazimine (CFZ), would alleviate TBI-induced white matter pathology in rodents. Postinjury CFZ administration prevented suppression of compound action potential (CAP) amplitude in the corpus callosum of adult rats following midline fluid percussion TBI, with injury and treatment effects primarily expressed in unmyelinated CAPs. Kv1.3 protein levels in callosal tissue extracts were significantly reduced postinjury, but this loss was prevented by CFZ treatment. In parallel, CFZ also attenuated the injury-induced elevation in pro-inflammatory cytokine IL1-β. The effects of CFZ on glial function were further studied using mixed microglia/astrocyte cell cultures derived from P3-5 mouse corpus callosum. Cultures of callosal glia challenged with lipopolysaccharide exhibited a dramatic increase in IL1-β levels, accompanied by reactive morphological changes in microglia, both of which were attenuated by CFZ treatment. These results support a cell specific role for Kv1.3 signaling in white matter pathology after TBI, and suggest a treatment approach based on the blockade of these channels. This therapeutic strategy may be especially efficacious for normalizing neuro-glial interactions affecting unmyelinated axons after TBI. PMID:27302680

  1. Design of antibody-functionalized carbon nanotubes filled with radioactivable metals towards a targeted anticancer therapy

    Science.gov (United States)

    Spinato, Cinzia; Perez Ruiz de Garibay, Aritz; Kierkowicz, Magdalena; Pach, Elzbieta; Martincic, Markus; Klippstein, Rebecca; Bourgognon, Maxime; Wang, Julie Tzu-Wen; Ménard-Moyon, Cécilia; Al-Jamal, Khuloud T.; Ballesteros, Belén; Tobias, Gerard; Bianco, Alberto

    2016-06-01

    In the present work we have devised the synthesis of a novel promising carbon nanotube carrier for the targeted delivery of radioactivity, through a combination of endohedral and exohedral functionalization. Steam-purified single-walled carbon nanotubes (SWCNTs) have been initially filled with radioactive analogues (i.e. metal halides) and sealed by high temperature treatment, affording closed-ended CNTs with the filling material confined in the inner cavity. The external functionalization of these filled CNTs was then achieved by nitrene cycloaddition and followed by the derivatization with a monoclonal antibody (Cetuximab) targeting the epidermal growth factor receptor (EGFR), overexpressed by several cancer cells. The targeting efficiency of the so-obtained conjugate was evaluated by immunostaining with a secondary antibody and by incubation of the CNTs with EGFR positive cells (U87-EGFR+), followed by flow cytometry, confocal microscopy or elemental analyses. We demonstrated that our filled and functionalized CNTs can internalize more efficiently in EGFR positive cancer cells.In the present work we have devised the synthesis of a novel promising carbon nanotube carrier for the targeted delivery of radioactivity, through a combination of endohedral and exohedral functionalization. Steam-purified single-walled carbon nanotubes (SWCNTs) have been initially filled with radioactive analogues (i.e. metal halides) and sealed by high temperature treatment, affording closed-ended CNTs with the filling material confined in the inner cavity. The external functionalization of these filled CNTs was then achieved by nitrene cycloaddition and followed by the derivatization with a monoclonal antibody (Cetuximab) targeting the epidermal growth factor receptor (EGFR), overexpressed by several cancer cells. The targeting efficiency of the so-obtained conjugate was evaluated by immunostaining with a secondary antibody and by incubation of the CNTs with EGFR positive cells (U87

  2. Design of nanodrugs for miRNA targeting in tumor cells (13-510-R)

    OpenAIRE

    Yoo, Byunghee; Ghosh, Subrata K.; Kumar, Mohanraja; Moore, Anna; Yigit, Mehmet V.; Medarova, Zdravka

    2014-01-01

    The delivery of oligonucleotide antagonists to cytosolic RNA targets such as microRNA represents an avenue for the post-transcriptional control of cellular phenotype. In tumor cells, oncogenic miRNAs, termed oncomirs, are tightly linked to processes that ultimately determine cancer initiation, progression, and response to therapy. Therefore, the capacity to redirect tumor cell fate towards therapeutically beneficial phenotypes holds promise in a future clinical scenario. Previously, we have d...

  3. Do-Fluoride "Cryolite By- product Carbon White" Awarded the 13th China Excellent Patent Award%Do-Fluoride "Cryolite By- product Carbon White" Awarded the 13th China Excellent Patent Award

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    On November 4, the results of the 13th China Patent Awards were publicized by the State Intellectual Property Office of the People's Republic of China. The patent of "production method of cryolite by-product carbon white" declared by Henan Province Jiaozuo Do-Fluoride Company was awarded China Excellent Patent Award.

  4. Differentiation of Pigment in Eggs Using Carbon ((13)C/(12)C) and Nitrogen ((15)N/(14)N) Stable Isotopes.

    Science.gov (United States)

    Sun, Feng M; Shi, Guang Y; Wang, Hui W

    2016-07-01

    Consumers prefer natural and healthy food, but artificial pigments are often abused in egg products. The study aimed at differentiating the origin of pigments in eggs by applying the technique of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) stable isotope analysis. Five hundred sixty laying hens were randomly distributed into 14 treatments, which were divided into four groups: maize, carophyll red pigment, carophyll yellow pigment, and a mixture of carophyll red and yellow pigments. Eggs were collected and pretreated to determe the values of the Roche Yolk Color Fan (RCF), δ(13)C, and δ(15)N. With increasing maize content, the RCF and δ(13)C values of yolks increased. Moreover, the RCF values in the three pigment groups were significantly influenced by the artificial colors, but δ(13)C values were not significantly different, regardless of the existence of pigment. The δ(15)N values in all treatments did not vary as regularly as the carbon stable isotope. A strong positive correlation was found between RCF and δ(13)C in the maize group, but no such correlation was be observed in the pigment groups. It is concluded that carbon stable isotope ratio analysis (δ(13)C) of the yolk can be used to differentiate the origin of the pigment added to eggs.

  5. Differentiation of Pigment in Eggs Using Carbon ((13)C/(12)C) and Nitrogen ((15)N/(14)N) Stable Isotopes.

    Science.gov (United States)

    Sun, Feng M; Shi, Guang Y; Wang, Hui W

    2016-07-01

    Consumers prefer natural and healthy food, but artificial pigments are often abused in egg products. The study aimed at differentiating the origin of pigments in eggs by applying the technique of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) stable isotope analysis. Five hundred sixty laying hens were randomly distributed into 14 treatments, which were divided into four groups: maize, carophyll red pigment, carophyll yellow pigment, and a mixture of carophyll red and yellow pigments. Eggs were collected and pretreated to determe the values of the Roche Yolk Color Fan (RCF), δ(13)C, and δ(15)N. With increasing maize content, the RCF and δ(13)C values of yolks increased. Moreover, the RCF values in the three pigment groups were significantly influenced by the artificial colors, but δ(13)C values were not significantly different, regardless of the existence of pigment. The δ(15)N values in all treatments did not vary as regularly as the carbon stable isotope. A strong positive correlation was found between RCF and δ(13)C in the maize group, but no such correlation was be observed in the pigment groups. It is concluded that carbon stable isotope ratio analysis (δ(13)C) of the yolk can be used to differentiate the origin of the pigment added to eggs. PMID:27302905

  6. Proceedings of the 13th biennial conference on carbon. Extended abstracts and program

    International Nuclear Information System (INIS)

    Properties of carbon are covered including: mechanical and frictional properties; chemical reactivity and surfaces; aerospace applications; carbonization and graphitization; industrial applications; electrical and thermal properties; biomaterials applications; fibers and composites; nuclear applications; activated carbon and adsorption; advances in carbon characterization; and micromechanics and modeling

  7. Proceedings of the 13th biennial conference on carbon. Extended abstracts and program

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-01-01

    Properties of carbon are covered including: mechanical and frictional properties; chemical reactivity and surfaces; aerospace applications; carbonization and graphitization; industrial applications; electrical and thermal properties; biomaterials applications; fibers and composites; nuclear applications; activated carbon and adsorption; advances in carbon characterization; and micromechanics and modeling. (GHT)

  8. The RB1 gene is the target of chromosome 13 deletions in malignant fibrous histiocytoma.

    Science.gov (United States)

    Chibon, F; Mairal, A; Fréneaux, P; Terrier, P; Coindre, J M; Sastre, X; Aurias, A

    2000-11-15

    Forty-four malignant fibrous histiocytomas (MFHs) were studied by comparative genomic hybridization. Among the observed imbalances, losses of the 13q14-q21 region were observed in almost all tumors (78%), suggesting that a gene localized in this region could act as a tumor suppressor gene and that its inactivation could be relevant for MFH oncogenesis and/or progression. We determined by CA repeat analyses a consensus region of deletion focusing on the RB1 region. The RB1 gene was then analyzed by protein truncation test, direct sequencing, fluorescence in situ hybridization, Southern blotting, and immunohistochemistry. RB1 mutations and/or homozygous deletions were found in 7 of the 34 tumors analyzed (20%). Among the 35 tumors with comparative genomic hybridization imbalances analyzed by immunohistochemistry, 30 (86%) did not exhibit significant nuclear labeling. The high correlation between chromosome 13 losses and absence of RB1 protein expression and the mutations detected strongly suggest that RB1 gene inactivation is a pivotal event in MFH oncogenesis. Moreover, the observation of a high incidence of MFH in patients previously treated for hereditary retinoblastoma fits well this hypothesis. PMID:11103795

  9. Vascular targeted single-walled carbon nanotubes for near-infrared light therapy of cancer

    Science.gov (United States)

    Prickett, Whitney M.; Van Rite, Brent D.; Resasco, Daniel E.; Harrison, Roger G.

    2011-11-01

    A new approach for targeting carbon nanotubes to the tumor vasculature was tested using human endothelial cells and MCF-7 breast cancer cells in vitro. Single-walled carbon nanotubes were functionalized with the F3 peptide using a polyethylene glycol linker to target nucleolin, a protein found on the surface of endothelial cells in the vasculature of solid tumors. Confocal microscopy and Raman analysis confirmed that the conjugate was internalized by actively dividing endothelial cells. Dividing endothelial cells were used to mimic these cells in the tumor vasculature. Incubation with the conjugate for 8 h or more caused significant cell death in both actively dividing endothelial cells and MCF-7 breast cancer cells, an effect that is hypothesized to be due to the massive uptake of the conjugate. This targeted cell killing was further enhanced when coupled with near-infrared laser treatment. For confluent (non-dividing) endothelial cells, no cytotoxic effect was seen for incubation alone or incubation coupled with laser treatment. These results are promising and warrant further studies using this conjugate for cancer treatment in vivo.

  10. Nuclear Structure Studies in the 132Sn Region: Safe Coulex with Carbon Targets

    Energy Technology Data Exchange (ETDEWEB)

    Allmond, James M [ORNL; Stuchbery, Andrew E [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Padilla-Rodal, Elizabeth [Universidad Nacional Autonoma de Mexico (UNAM); Radford, David C [ORNL; Batchelder, J. C. [Oak Ridge Associated Universities (ORAU); Bingham, C. R. [University of Tennessee, Knoxville (UTK); Howard, Meredith E [ORNL; Liang, J Felix [ORNL; Manning, Brett M [ORNL; Pain, Steven D [ORNL; Stone, N. J. [University of Tennessee, Knoxville (UTK); Varner, Jr, Robert L [ORNL; Yu, Chang-Hong [ORNL

    2015-01-01

    The collective and single-particle structure of nuclei in the 132Sn region was recently studied by Coulomb excitation and heavy-ion induced transfer reactions using carbon, beryllium, and titanium targets. In particular, Coulomb excitation was used determine a complete set of electromagnetic moments for the first 2+ states and one-neutron transfer was used to probe the purity and evolution of single-neutron states. These recent experiments were conducted at the Holifield Radioactive Ion Beam Facility at ORNL using a CsI-HPGe detector array (BareBall- CLARION) to detect scattered particles and emitted gamma rays from the in-beam reactions. A Bragg-curve detector was used to measure the energy loss of the various beams through the targets and to measure the radioactive beam compositions. A sample of the Coulomb excitation results is presented here with an emphasis placed on 116Sn. In particular, the safe Coulex criterion for carbon targets will be analyzed and discussed.

  11. Vascular targeted single-walled carbon nanotubes for near-infrared light therapy of cancer

    International Nuclear Information System (INIS)

    A new approach for targeting carbon nanotubes to the tumor vasculature was tested using human endothelial cells and MCF-7 breast cancer cells in vitro. Single-walled carbon nanotubes were functionalized with the F3 peptide using a polyethylene glycol linker to target nucleolin, a protein found on the surface of endothelial cells in the vasculature of solid tumors. Confocal microscopy and Raman analysis confirmed that the conjugate was internalized by actively dividing endothelial cells. Dividing endothelial cells were used to mimic these cells in the tumor vasculature. Incubation with the conjugate for 8 h or more caused significant cell death in both actively dividing endothelial cells and MCF-7 breast cancer cells, an effect that is hypothesized to be due to the massive uptake of the conjugate. This targeted cell killing was further enhanced when coupled with near-infrared laser treatment. For confluent (non-dividing) endothelial cells, no cytotoxic effect was seen for incubation alone or incubation coupled with laser treatment. These results are promising and warrant further studies using this conjugate for cancer treatment in vivo.

  12. Influence of Catalyst and Polymerization Conditions on the Properties of 1,3-Trimethylene Carbonate and ε-Caprolactone Copolymers

    NARCIS (Netherlands)

    Pego, Ana Paula; Zhong, Zhiyuan; Dijkstra, Pieter J.; Grijpma, Dirk W.; Feijen, Jan

    2003-01-01

    The influence of the catalyst/initiator system and polymerization conditions on the microstructure and physical properties of copolymers of equimolar amounts of 1,3-trimethylene carbonate (TMC) and -caprolactone (CL) was studied. Statistical copolymers were prepared in the presence of stannous octoa

  13. STUDY ON THE SEQUENCE STRUCTURE OF SBR BY 13C- NMR METHOD Ⅰ. ASSIGNMENT FOR UNSATURATED CARBONS SPECTRA

    Institute of Scientific and Technical Information of China (English)

    JIAO Shuke; CHEN Xiaonong; HU Liping; YAN Baozhen

    1990-01-01

    The sequence structures of emulsion- processed SBR and solution- processed ( by lithium catalyst )SBR were investigated by 13C- NMR spectroscopy. Seventeen peaks within unsaturated carbon region were recorded under the adopted experimental conditions. Assignments for these peaks were made by empirical- parameter- evaluation method.

  14. STUDY ON THE SEQUENCE STRUCTURE OF SBR BY 13C- NMR METHOD Ⅱ . PEAK ASSIGNMENT FOR ALIPHATIC CARBONS SPECTRA

    Institute of Scientific and Technical Information of China (English)

    JIAO Shuke; CHEN Xiaonong; HU Liping; YAN Baozhen

    1990-01-01

    The study on 13C-NMR spectra of aliphatic carbon region of emulsion-processed and solution-processed ( by lithium catalyst ) SBR was carried out. The assignments for more than thirty odd peaks observed experimentally were made by using " corresponding analysis " method, combined with the empirical parameters reported in literature. The peak intensities were calculated based on Bernoullian statistic assumption.

  15. Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea under mild conditions

    Institute of Scientific and Technical Information of China (English)

    Jun Jie Gao; Hui Quan Li; Yi Zhang

    2007-01-01

    Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.

  16. De novo LINE-1 retrotransposition in HepG2 cells preferentially targets gene poor regions of chromosome 13.

    Science.gov (United States)

    Bojang, Pasano; Anderton, Mark J; Roberts, Ruth A; Ramos, Kenneth S

    2014-08-01

    Long interspersed nuclear elements (Line-1 or L1s) account for ~17% of the human genome. While the majority of human L1s are inactive, ~80-100 elements remain retrotransposition competent and mobilize through RNA intermediates to different locations within the genome. De novo insertions of L1s account for polymorphic variation of the human genome and disruption of target loci at their new location. In the present study, fluorescence in situ hybridization and DNA sequencing were used to characterize retrotransposition profiles of L1(RP) in cultured human HepG2 cells. While expression of synthetic L1(RP) was associated with full-length and truncated insertions throughout the entire genome, a strong preference for gene-poor regions, such as those found in chromosome 13 was observed for full-length insertions. These findings shed light into L1 targeting mechanisms within the human genome and question the putative randomness of L1 retrotransposition.

  17. Carbon Cycling in Floodplain Ecosystems: Out-Gassing and Photosynthesis Transmit Soil d13C Gradient Through Stream Food Webs

    DEFF Research Database (Denmark)

    Gray, Duncan P.; Harding, Jon S.; Elberling, Bo;

    2011-01-01

    to assess the sources of carbon to spring food webs. Partial pressures of CO2 in upwelling water ranged from 2 to 7 times atmospheric pressure, but rapidly approached equilibrium with the atmosphere downstream commensurate with 13C enrichment of DIC. Speciation modeling and a laboratory out......Natural braided river floodplains typically possess high groundwater–surface water exchange, which is vital to the overall function and structure of these complex ecosystems. Spring-fed streams on the floodplain are also hotspots of benthic invertebrate diversity and productivity. The sources...... of carbon that drive these productive spring-fed systems are not well-known. We conducted field assessments and a manipulation, modeling, and a laboratory experiment to address this issue. Initially d13C values of both dissolved inorganic carbon (DIC) and food-web components of five springs were used...

  18. Seasonal variations of belowground carbon transfer assessed by in situ 13CO2 pulse labelling of trees

    Directory of Open Access Journals (Sweden)

    P. Priault

    2011-02-01

    Full Text Available Soil CO2 efflux is the main source of CO2 from forest ecosystems and it is tightly coupled to the transfer of recent photosynthetic assimilates belowground and their metabolism in roots, mycorrhiza and rhizosphere microorganisms feeding on root-derived exudates. The objectives of our study were to assess patterns of belowground carbon allocation among tree species and along seasons. Pure 13CO2 pulse labelling of the entire crown of three different tree species (beech, oak and pine was carried out at distinct phenological stages. Excess 13C in soil CO2 efflux was tracked using tunable diode laser absorption spectrometry to determine time lags between the start of the labelling and the appearance of 13C in soil CO2 efflux and the amount of 13C allocated to soil CO2 efflux. Isotope composition (δ13C of CO2 respired by fine roots and soil microbes was measured at several occasions after labelling, together with δ13C of bulk root tissue and microbial carbon. Time lags ranged from 0.5 to 1.3 days in beech and oak and were longer in pine (1.6–2.7 days during the active growing season, more than 4 days during the resting season, and the transfer of C to the microbial biomass was as fast as to the fine roots. The amount of 13C allocated to soil CO2 efflux was estimated from a compartment model. Seasonal patterns of carbon allocation to soil CO2 efflux differed markedly between species, with pronounced seasonal variations in pine and beech. In beech, it may reflect competition with other sinks (aboveground growth in late spring and storage in late summer that were not observed in oak.

  19. Biology and air–sea gas exchange controls on the distribution of carbon isotope ratios (δ13C) in the ocean

    OpenAIRE

    A. Schmittner; Gruber, N.; Mix, A. C.; Key, R.M.; Tagliabue, A.; Westberry, T. K.

    2013-01-01

    Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate the processes that control the distribution of δ13C in the contemporary and preindustrial ocean. Biological fractionation dominates the distribution of δ13CDIC of dissolved inorganic carbon (DIC) due to the sinking of isotopically light δ13C organic matter from the surface into the interior ocean. This process leads to low δ13CDI...

  20. Use of carbon-13 as a population marker for Anopheles arabiensis in a sterile insect technique (SIT context

    Directory of Open Access Journals (Sweden)

    Knols Bart GJ

    2006-01-01

    Full Text Available Abstract Background Monitoring of sterile to wild insect ratios in field populations can be useful to follow the progress in genetic control programmes such as the Sterile Insect Technique (SIT. Of the numerous methods for marking insects most are not suitable for use in mass rearing and mass release. Suitable ones include dye marking, genetic marking and chemical marking. Methods The feasibility of using the stable isotope of carbon, 13C, as a potential chemical marker for Anopheles arabiensis was evaluated in the laboratory. Labeled-13C glucose was incorporated into the larval diet in a powder or liquid form. The contribution of adult sugar feeding to the total mosquito carbon pool and the metabolically active carbon pool was determined by tracing the decline of the enrichment of the adult male mosquito as it switched from a labeled larval diet to an unlabeled adult diet. This decline in the adult was monitored by destructive sampling of the whole mosquito and analyzed using isotope ratio mass spectrometry. Results A two-pool model was used to describe the decline of the 13C-enrichment of adult mosquitoes. The proportion of the total adult carbon pool derived from the adult sugar diet over the life span of mosquitoes was determined and the ratio of structural carbon, with a low turnover rate to metabolically active non-structural carbon was assessed. The uptake and turnover of sugar in the metabolically active fraction suggests that after 3 days >70% of the active fraction carbon is derived from sugar feeding (increasing to >90% by day 7, indicating the high resource demand of male mosquitoes. Conclusion It was possible to "fix" the isotopic label in adult An. arabiensis and to detect the label at an appropriate concentration up to 21 days post-emergence. The optimum labeling treatment would cost around 250 US$ per million mosquitoes. Stable isotope marking may thus aid research on the fate of released insects besides other population

  1. Seasonal variations of belowground carbon transfer assessed by in situ 13CO2 pulse labelling of trees

    Directory of Open Access Journals (Sweden)

    L. Barthes

    2011-05-01

    Full Text Available Soil CO2 efflux is the main source of CO2 from forest ecosystems and it is tightly coupled to the transfer of recent photosynthetic assimilates belowground and their metabolism in roots, mycorrhiza and rhizosphere microorganisms feeding on root-derived exudates. The objective of our study was to assess patterns of belowground carbon allocation among tree species and along seasons. Pure 13CO2 pulse labelling of the entire crown of three different tree species (beech, oak and pine was carried out at distinct phenological stages. Excess 13C in soil CO2 efflux was tracked using tuneable diode laser absorption spectrometry to determine time lags between the start of the labelling and the appearance of 13C in soil CO2 efflux and the amount of 13C allocated to soil CO2 efflux. Isotope composition (δ13C of CO2 respired by fine roots and soil microbes was measured at several occasions after labelling, together with δ13C of bulk root tissue and microbial carbon. Time lags ranged from 0.5 to 1.3 days in beech and oak and were longer in pine (1.6–2.7 days during the active growing season, more than 4 days during the resting season, and the transfer of C to the microbial biomass was as fast as to the fine roots. The amount of 13C allocated to soil CO2 efflux was estimated from a compartment model. It varied between 1 and 21 % of the amount of 13CO2 taken up by the crown, depending on the species and the season. While rainfall exclusion that moderately decreased soil water content did not affect the pattern of carbon allocation to soil CO2 efflux in beech, seasonal patterns of carbon allocation belowground differed markedly between species, with pronounced seasonal variations in pine and beech. In beech, it may reflect competition with the strength of other sinks (aboveground growth in late spring and storage in late summer that were not observed in oak. We report a fast transfer of recent photosynthates to the mycorhizosphere and we conclude that the

  2. How to trigger low carbon technologies by EU targets for 2030? An assessment of technology needs

    Energy Technology Data Exchange (ETDEWEB)

    Groenenberg, H.; Van Breevoort, P.; Janeiro, L.; Winkel, T.

    2013-04-15

    The current EU framework for energy and climate policies up to 2020 consists of three headline targets: 20% reduction of GHG emissions compared to 2005, a 20% share of renewable energy in final energy consumption, and 20% primary energy savings compared to baseline developments. While progress on these 2020 targets is mixed, discussions in the EU about climate and energy policies and targets for the period after 2020 have started. Given the long cycles associated to energy and climate investments, agreement on a clear longer-term policy framework is critical to improve visibility for investors and avoid lock-in effects in inefficient or polluting technologies. Therefore, the European Commission published a Communication on 6 June 2012 on the need for a long term policy framework for renewable energy, and a Green Paper on the 2030 climate and energy policy framework on 27 March 2013. Against this background, the Dutch Ministries of Infrastructure and Environment and the Ministry of Economic Affairs requested PBL to create input for the European debate on climate targets and policies until and beyond 2030. Ecofys supported PBL by addressing the following two questions: (1) What steps are needed for selected key technology groups to achieve long term GHG emission reductions and what climate and energy policies are likely to trigger these steps?; and (2) What are the pros and cons of a 2030 policy framework with (a) a GHG reduction target only, and (b) targets for GHG reduction, renewable energy, and energy efficiency? The focus of the first question was on four technology groups, namely (1) energy efficiency in the built environment, notably for heat; (2) solar PV and wind energy; (3) advanced biofuels; (4) CO2 carbon capture and storage (CCS). An analysis of the steps needed for the deployment of the full GHG mitigation potential of the discussed technology groups shows that this will largely depend on the adoption of a wide range of policy instruments by EU Member

  3. Preferential formation of 13C- 18O bonds in carbonate minerals, estimated using first-principles lattice dynamics

    Science.gov (United States)

    Schauble, Edwin A.; Ghosh, Prosenjit; Eiler, John M.

    2006-05-01

    Equilibrium constants for internal isotopic exchange reactions of the type: Ca12C18O16O2+Ca13C16O3↔Ca13C18O16O2+Ca12C16O3 for individual CO 32- groups in the carbonate minerals calcite (CaCO 3), aragonite (CaCO 3), dolomite (CaMg(CO 3) 2), magnesite (MgCO 3), witherite (BaCO 3), and nahcolite (NaHCO 3) are calculated using first-principles lattice dynamics. Calculations rely on density functional perturbation theory (DFPT) with norm-conserving planewave pseudopotentials to determine the vibrational frequencies of isotopically substituted crystals. Our results predict an ˜0.4‰ excess of 13C18O16O22- groups in all studied carbonate minerals at room-temperature equilibrium, relative to what would be expected in a stochastic mixture of carbonate isotopologues with the same bulk 13C/ 12C, 18O/ 16O, and 17O/ 16O ratios. The amount of excess 13C18O16O22- decreases with increasing temperature of equilibration, from 0.5‰ at 0 °C to <0.1‰ at 300 °C, suggesting that measurements of multiply substituted isotopologues of carbonate could be used to infer temperatures of ancient carbonate mineral precipitation and alteration events, even where the δ 18O of coexisting fluids is uncertain. The predicted temperature sensitivity of the equilibrium constant is ˜0.003‰/°C at 25 °C. Estimated equilibrium constants for the formation of 13C18O16O22- are remarkably uniform for the variety of minerals studied, suggesting that temperature calibrations will also be applicable to carbonate minerals not studied here without greatly compromising accuracy. A related equilibrium constant for the reaction: Ca12C18O16O2+Ca12C17O16O2↔Ca12C18O17O16O+Ca12C16O3 in calcite indicates formation of 0.1‰ excess 12C 18O 17O 16O 2- at 25 °C. In a conventional phosphoric acid reaction of carbonate to form CO 2 for mass-spectrometric analysis, molecules derived from 13C18O16O22- dominate (˜96%) the mass 47 signal, and 12C 18O 17O 16O 2- contributes most of the remainder (3%). This suggests

  4. Study of secondary electron emission from thin carbon targets with swift charged particles: heavy ions, hydrogen ions

    International Nuclear Information System (INIS)

    The main subject of this work is the study of electron emission from the two surfaces of thin solid targets bombarded with swift charged particles. The slowing down of swift ions in matter is mainly due to inelastic interaction with target electrons (ionization, excitation): the energy transfer to target electrons is responsible for the secondary electron emission process. The phenomenological and theoretical descriptions of this phenomena are the subject of the first chapter. We focused on secondary electron emission induced by different kind of projectiles on thin carbon foils. In chapter two we describe hydrogen cluster induced electron emission measurement between 40 and 120 keV/proton. These projectiles, composed of several atoms, allowed us to study and highlight collective effects of the electron emission process. We extended our study of electron emission to molecular (H2+, H3+) and composite (H-, H0) projectiles at higher energies (<= 2 MeV): we have designed an experimental set-up devoted to electron emission statistics measurements which allowed us to study, among others things, the role of projectile electrons in secondary electron emission. This experiment is described in the third chapter. Finally, the fourth chapter describes new measurements of electron emission induced by energetic (13 MeV/u) and highly charged argon ion provided by the medium energy beam line (SME) of GANIL (Caen), which have been analyzed in the framework of a semi-empirical model of secondary electron emission. This set of experiments brings new results on composite projectile interaction with matter, and on the consequences of high energy deposition in solids. (author)

  5. The scattering of a bremsstrahlung radiation of electrons with energy 13 and 22 MeV from plane targets

    CERN Document Server

    Asatov, U T

    2002-01-01

    In the present work the characteristics of backward (90 sup d eg13 and 22 MeV with plane targets of different thickness from glass textolite, aluminium, iron, lead and their combination are investigated. The dependence of thickness of saturation of 'forward' scattered gamma radiation, a on angles of detection (theta sub s) and orientation (phi) of plane targets depending on a direction of probing beam was observed for the first time. For the first time, the numerical performances of beams of forward scattered gamma radiation from different targets were investigated and determined depending on their orientation and thickness. The new and corrected data on numerical performances of beams of the inverse scattered gamma radiation is obtained. The distinction in characteristics of beams of the scattered gamma radiation is s...

  6. Functional single-walled carbon nanotubes/chitosan conjugate for tumor cells targeting

    Science.gov (United States)

    Wu, Baoyan; Ou, Zhongmin; Xing, Da

    2009-08-01

    The application of single-walled carbon nanotubes (SWCNTs) in the field of biomedicine is becoming an exciting topic because of their flexible structure and propensity for chemical functionalization. In this assay, a novel noncovalently functional SWCNTs based on a natural biocompatible polymer chitosan has been developed for tumor cells targeting. First, SWCNTs were modified by chitosan (CHIT-SWCNT). Second, CHIT-SWCNT was coupled with fluorescein isothiocyanate (FITC), based on the reaction between the isothiocyanate group of FITC and the primary amino group of chitosan. Third, the FITC functionalized CHIT-SWCNT was conjugated with folic acid (FA) after activation with EDC/NHS, based on the reaction between the NHS group of FA and the primary free amino group of chitosan to construct the functional SWCNT/CHIT conjugate, CHIT-SWCNT-FA. The fluorescence CHIT-SWCNT-FA has been used to detect tumor cells with confocal microscopy imaging technology. Our experimental results indicate that the novel CHIT-SWCNT-FA is soluble and stable in PBS, and it can be readily transported inside tumor cells. Combining the intrinsic properties of carbon nanotubes and the versatility of chitosan, CHIT-SWCNT can be used as potential devices for targeted drug delivery and tumor cell sensing. The proposed assay could provide a feasible alternative to presently available functional SWCNTs in biological applications.

  7. Carbon-13 nuclear magnetic resonance spectroscopic studies of 13CO adsorbed on platinum particles in L-zeolites

    International Nuclear Information System (INIS)

    13CO chemisorbed on platinum particles in L-zeolite has been investigated by static and magic angles spinning NMR spectroscopy. The representative spectra ate composed of a broad asymmetric peak with a center of gravity at 230±30 ppm and a sharp symmetric peak at 124±2 ppm which is tentatively assigned to physisorbed CO2 on inner walls of L-zeolite. Overall, the broad resonance component is similar to our previous results of highly dispersed (80-96%) CO/Pt/silica or CO/Pt/alumina samples, still showing metallic characters. The principal difference is in the first moment value. The broad peak in the spectra is assigned to CO linearly bound to Pt particles in the L-zeolites, and indicates a distribution of isotropic shifts from bonding site to bonding site. The NMR results reported here manifest that the Pt particles inside of the L-zeolites channels are not collectively the same with the ones supported on silica or alumina with similar dispersion in terms of Pt particle shape and/or ordering of Pt atoms in a particle. As a result, Pt particles of CO/Pt/L-zeolite were agglomerated accompanying CO desorption upon annealing. There were no definite changes in the NMR spectra due to differences of exchanged cations. Comparison of our observation on CO/Pt/L-zeolite with Sharma et al.'s reveals that even when the first moment, the linewidth, and the relaxation times of the static spectra and the dispersion measured by chemisorption are similar, the properties of Pt particles can be dramatically different. Therefore, it is essential to take advantage of the strengths of several techniques together in order to interpret data reliably, especially for the highly dispersed samples

  8. A new peptide ligand for targeting human carbonic anhydrase IX, identified through the phage display technology.

    Directory of Open Access Journals (Sweden)

    Vasileios Askoxylakis

    Full Text Available UNLABELLED: Carbonic anhydrase IX (CAIX is a transmembrane enzyme found to be overexpressed in various tumors and associated with tumor hypoxia. Ligands binding this target may be used to visualize hypoxia, tumor manifestation or treat tumors by endoradiotherapy. METHODS: Phage display was performed with a 12 amino acid phage display library by panning against a recombinant extracellular domain of human carbonic anhydrase IX. The identified peptide CaIX-P1 was chemically synthesized and tested in vitro on various cell lines and in vivo in Balb/c nu/nu mice carrying subcutaneously transplanted tumors. Binding, kinetic and competition studies were performed on the CAIX positive human renal cell carcinoma cell line SKRC 52, the CAIX negative human renal cell carcinoma cell line CaKi 2, the human colorectal carcinoma cell line HCT 116 and on human umbilical vein endothelial cells (HUVEC. Organ distribution studies were carried out in mice, carrying SKRC 52 tumors. RNA expression of CAIX in HCT 116 and HUVEC cells was investigated by quantitative real time PCR. RESULTS: In vitro binding experiments of (125I-labeled-CaIX-P1 revealed an increased uptake of the radioligand in the CAIX positive renal cell carcinoma cell line SKRC 52. Binding of the radioligand in the colorectal carcinoma cell line HCT 116 increased with increasing cell density and correlated with the mRNA expression of CAIX. Radioligand uptake was inhibited up to 90% by the unlabeled CaIX-P1 peptide, but not by the negative control peptide octreotide at the same concentration. No binding was demonstrated in CAIX negative CaKi 2 and HUVEC cells. Organ distribution studies revealed a higher accumulation in SKRC 52 tumors than in heart, spleen, liver, muscle, intestinum and brain, but a lower uptake compared to blood and kidney. CONCLUSIONS: These data indicate that CaIX-P1 is a promising candidate for the development of new ligands targeting human carbonic anhydrase IX.

  9. The 'Nuts and Bolts' of 13C NMR Spectroscopy at Elevated-Pressures and -Temperatures for Monitoring In Situ CO2 Conversion to Metal Carbonates

    Science.gov (United States)

    Moore, J. K.; Surface, J. A.; Skemer, P. A.; Conradi, M. S.; Hayes, S. E.

    2013-12-01

    We will present details of newly-constructed specialized NMR designed to conduct in situ elevated-pressure, elevated-temperature 13C NMR studies on unmixed slurries of minerals in the presence of CO2 or other gases. This static probe is capable of achieving 300 bar, 300C conditions, and it is designed to spectroscopically examine 13C signals in mixtures of solids, liquids, gases, and supercritical fluids. Ultimately, our aim is to monitor CO2 uptake in both ultramafic rocks and in more porous geological materials to understand the mechanisms of chemisorption as a function of temperature, pressure and pH. We will give details of the hardware setup, and we will show a variety of static in situ NMR, as well as ex situ 'magic-angle spinning' NMR to show the analyses that are possible of minerals in pure form and in mixtures. In addition, specific NMR pulse sequences, techniques, and modeling will be described in detail. In this in situ NMR probe, we are able to simulate processes at geologically relevant fluid pressures and temperatures, monitoring the kinetics of CO2 conversion to carbonates. The in situ NMR experiments consist of heterogeneous mixtures of rock, salty brine solution, and moderate pressure CO2 gas at elevated temperatures. The purpose of studying these reactions is to determine conditions that affect the efficacy of carbonate formation in various targeted geological reservoirs (i.e., peroditite, or others). Via 13C NMR, we have spectroscopically characterized and quantified the conversion of CO2 to magnesium carbonate and calcium carbonate minerals, including metastable intermediates (such as hydromagnesite, or dypingite in the case of magnesium carbonate species, or vaterite in the case of calcium carbonate species). Such species are distinguishable from a combination of the 13C isotropic chemical shift, the static 13C lineshape, and changes in spin-lattice (T1) relaxation times. We will demonstrate that NMR can be used for quantitative

  10. Engineering Multi-Walled Carbon Nanotube Therapeutic Bionanofluids to Selectively Target Papillary Thyroid Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Idit Dotan

    Full Text Available The incidence of papillary thyroid carcinoma (PTC has risen steadily over the past few decades as well as the recurrence rates. It has been proposed that targeted ablative physical therapy could be a therapeutic modality in thyroid cancer. Targeted bio-affinity functionalized multi-walled carbon nanotubes (BioNanofluid act locally, to efficiently convert external light energy to heat thereby specifically killing cancer cells. This may represent a promising new cancer therapeutic modality, advancing beyond conventional laser ablation and other nanoparticle approaches.Thyroid Stimulating Hormone Receptor (TSHR was selected as a target for PTC cells, due to its wide expression. Either TSHR antibodies or Thyrogen or purified TSH (Thyrotropin were chemically conjugated to our functionalized Bionanofluid. A diode laser system (532 nm was used to illuminate a PTC cell line for set exposure times. Cell death was assessed using Trypan Blue staining.TSHR-targeted BioNanofluids were capable of selectively ablating BCPAP, a TSHR-positive PTC cell line, while not TSHR-null NSC-34 cells. We determined that a 2:1 BCPAP cell:α-TSHR-BioNanofluid conjugate ratio and a 30 second laser exposure killed approximately 60% of the BCPAP cells, while 65% and >70% of cells were ablated using Thyrotropin- and Thyrogen-BioNanofluid conjugates, respectively. Furthermore, minimal non-targeted killing was observed using selective controls.A BioNanofluid platform offering a potential therapeutic path for papillary thyroid cancer has been investigated, with our in vitro results suggesting the development of a potent and rapid method of selective cancer cell killing. Therefore, BioNanofluid treatment emphasizes the need for new technology to treat patients with local recurrence and metastatic disease who are currently undergoing either re-operative neck explorations, repeated administration of radioactive iodine and as a last resort external beam radiation or chemotherapy, with

  11. Engineering Multi-Walled Carbon Nanotube Therapeutic Bionanofluids to Selectively Target Papillary Thyroid Cancer Cells

    Science.gov (United States)

    Paliouras, Miltiadis; Mitmaker, Elliot J.; Trifiro, Mark A.

    2016-01-01

    Background The incidence of papillary thyroid carcinoma (PTC) has risen steadily over the past few decades as well as the recurrence rates. It has been proposed that targeted ablative physical therapy could be a therapeutic modality in thyroid cancer. Targeted bio-affinity functionalized multi-walled carbon nanotubes (BioNanofluid) act locally, to efficiently convert external light energy to heat thereby specifically killing cancer cells. This may represent a promising new cancer therapeutic modality, advancing beyond conventional laser ablation and other nanoparticle approaches. Methods Thyroid Stimulating Hormone Receptor (TSHR) was selected as a target for PTC cells, due to its wide expression. Either TSHR antibodies or Thyrogen or purified TSH (Thyrotropin) were chemically conjugated to our functionalized Bionanofluid. A diode laser system (532 nm) was used to illuminate a PTC cell line for set exposure times. Cell death was assessed using Trypan Blue staining. Results TSHR-targeted BioNanofluids were capable of selectively ablating BCPAP, a TSHR-positive PTC cell line, while not TSHR-null NSC-34 cells. We determined that a 2:1 BCPAP cell:α-TSHR-BioNanofluid conjugate ratio and a 30 second laser exposure killed approximately 60% of the BCPAP cells, while 65% and >70% of cells were ablated using Thyrotropin- and Thyrogen-BioNanofluid conjugates, respectively. Furthermore, minimal non-targeted killing was observed using selective controls. Conclusion A BioNanofluid platform offering a potential therapeutic path for papillary thyroid cancer has been investigated, with our in vitro results suggesting the development of a potent and rapid method of selective cancer cell killing. Therefore, BioNanofluid treatment emphasizes the need for new technology to treat patients with local recurrence and metastatic disease who are currently undergoing either re-operative neck explorations, repeated administration of radioactive iodine and as a last resort external beam

  12. Quantifying the roles of ocean circulation and biogeochemistry in governing ocean carbon-13 and atmospheric carbon dioxide at the last glacial maximum

    OpenAIRE

    Tagliabue, A.; L. Bopp; Roche, D. M.; N. Bouttes; J.-C. Dutay; Alkama, R.; Kageyama, M.; Michel, E.; Paillard, D.

    2009-01-01

    We use a state-of-the-art ocean general circulation and biogeochemistry model to examine the impact of changes in ocean circulation and biogeochemistry in governing the change in ocean carbon-13 and atmospheric CO2 at the last glacial maximum (LGM). We examine 5 different realisations of the ocean's overturning circulation produced by a fully coupled atmosphere-ocean model under LGM forcing and suggested changes in the atmospheric deposition of iron and phytoplankton ph...

  13. China's Voluntary Mitigation Target and Road of Low-carbon Development

    Institute of Scientific and Technical Information of China (English)

    He Jiankun

    2011-01-01

    China is going through a rapid development stage of industrialization and urbanization.Although tremendous achievements have been made in the aspects of energy conservation,improvement of energy effectiveness and development of new and renewable energies,because of the rapid development of economy,it is difficult to change the huge total amount and fast increase of CO2 emission in the near future.China has to confront the tough challenge to address global climate change.China plans to reduce carbon intensity,that is,CO2 emissions per unit GDP,by 40 to 45% by 2020 compared with the 2005 level.It is a strategic option to coordinate domestic sustainable development with coping with global climate change on the basis of China's national circumstances,representing the core content and key measures for transforming development pattern and realizing low-carbon development.To achieve the target,more capital and technology inputs are required for energy conservation and low-carbon development during the twelfth and Thirteenth Five Year Plan period than in the Eleventh Five Year Plan period.In addition,energy conservation achieved by structural adjustment,industrial upgrading and product value-added improvement is also expected to play a greater role.Therefore,China should strengthen technological innovation,make greater efforts to transform the development pattern,take advantage of the synergistic effect of policies and measures while coping with global climate change and building a domestic tow-oriented society.China should also establish an industrial system characterized by low-carbon emission.Then China will ultimately achieve a win-win situation in both domestic sustainable development and coping with global climate change.

  14. Direct uptake of organic carbon by grass roots and allocation in leaves and phytoliths: 13C labeling evidence

    Science.gov (United States)

    Alexandre, A.; Balesdent, J.; Cazevieille, P.; Chevassus-Rosset, C.; Signoret, P.; Mazur, J.-C.; Harutyunyan, A.; Doelsch, E.; Basile-Doelsch, I.; Miche, H.; Santos, G. M.

    2015-12-01

    In the rhizosphere, the uptake of low molecular weight carbon (C) and nitrogen (N) by plant roots has been well documented. While organic N uptake relatively to total uptake is important, organic C uptake is supposed to be low relatively to the plant's C budget. Recently, radiocarbon analyses demonstrated that a fraction of C from the soil was occluded in amorphous silica micrometric particles that precipitate in plant cells (phytoliths). Here, we investigated whether and in which extent organic C absorbed by grass roots, under the form of either intact amino acids (AAs) or microbial metabolites, can feed the organic C occluded in phytoliths. For this purpose we added 13C- and 15N-labeled AAs to the silicon-rich hydroponic solution of the grass Festuca arundinacea. The experiment was designed to prevent C leakage from the labeled nutritive solution to the chamber atmosphere. After 14 days of growth, the 13C and 15N enrichments (13C-excess and 15N-excess) in the roots, stems and leaves, and phytoliths, as well as the 13C-excess in AAs extracted from roots and stems and leaves, were quantified relatively to a control experiment in which no labelled AAs were added. The net uptake of 13C derived from the labeled AAs supplied to the nutritive solution (AA-13C) by Festuca arundinacea represented 4.5 % of the total AA-13C supply. AA-13C fixed in the plant represented only 0.13 % of total C. However, the experimental conditions may have underestimated the extent of the process under natural and field conditions. Previous studies showed that 15N and 13C can be absorbed by the roots in several organic and inorganic forms. In the present experiment, the fact that phenylalanine and methionine, that were supplied in high amount to the nutritive solution, were more 13C-enriched than other AAs in the roots and stems and leaves strongly suggested that part of AA-13C was absorbed and translocated in its original AA form. The concentration of AA-13C represented only 0.15 % of the

  15. Seasonal and interannual variability in 13C composition of ecosystem carbon fluxes in the U.S. Southern Great Plains

    OpenAIRE

    Torn, Margaret S.; Sebastien C. Biraud; Still, Christopher J.; Riley, William J; Berry, Joe A.

    2011-01-01

    The δ13C value of terrestrial CO2 fluxes (δbio) provides important information for inverse models of CO2 sources and sinks as well as for studies of vegetation physiology, C3 and C4 vegetation fluxes, and ecosystem carbon residence times. From 2002–2009, we measured atmospheric CO2 concentration and δ13C–CO2 at four heights (2 to 60 m) in the U.S. Southern Great Plains (SGP) and computed δbio weekly. This region has a fine-scale mix of crops (primarily C3 winter wheat) and C4 pasture grasses....

  16. Measurement of proton-induced target fragmentation cross sections in carbon

    Science.gov (United States)

    Matsushita, K.; Nishio, T.; Tanaka, S.; Tsuneda, M.; Sugiura, A.; Ieki, K.

    2016-02-01

    In proton therapy, positron emitter nuclei are generated via the target nuclear fragmentation reactions between irradiated proton and nuclei constituting a human body. The proton-irradiated volume can be confirmed with measurement of annihilation γ-rays from the generated positron emitter nuclei. To achieve the high accuracy of proton therapy, in vivo dosimetry, i.e., evaluation of the irradiated dose during the treatment is important. To convert the measured activity distribution to irradiated dose, cross-sectional data for positron emitter production is necessary, which is currently insufficient in the treatment area. The purpose of this study is to collect cross-sectional data of 12C (p , pn)11C and 12C (p , p 2 n)10C reactions between the incident proton and carbon nuclei, which are important target nuclear fragmentation reactions, to estimate the range and exposure dose distribution in the patient's body. Using planar-type PET capable of measuring annihilation γ-rays at high positional resolution and thick polyethylene target, we measured cross-sectional data in continuous wide energy range. The cross section of 12C (p , pn)11C is in good agreement with existing experimental data. The cross section of 12C (p , p 2 n)10C is reported for the first data in the low-energy range of 67.6-10.5 MeV near the Bragg peak of proton beam.

  17. The Effect of Mesoporous Carbon Nitride Modification by Titanium Oxide Nanoparticles on Photocatalytic Degradation of 1,3-Dinitrobenzene

    Directory of Open Access Journals (Sweden)

    Seyyed Ershad Moradi

    2015-11-01

    Full Text Available In the present work, well ordered, mesoporous carbon nitride (MCN sorbent with uniform mesoporous wall, high surface area and pore volume has been fabricated using the simple polymerization reaction between ethylene diamine and carbon tetrachloride in mesoporous silica media, and then modified by TiO2 nanoparticles (Ti-MCN. The structural order and textural properties of the nanoporous materials were studied by XRD, elemental analysis, and nitrogen adsorption–desorption experiments. Photodegradation experiments for 1,3-dinitrobenzene were conducted in batch mode, the Ti-MCN catalysts were found to be more active compared to the free TiO2 nanoparticles for 1,3-dinitrobenzene degradation.

  18. Foliar Carbon Isotope Composition (δ13C) and Water Use Efficiency of Different Populus deltoids Clones Under Water Stress

    Institute of Scientific and Technical Information of China (English)

    Zhao Fengjun; Gao Rongfu; Shen Yingbai; Su Xiaohua; Zhang Bingyu

    2006-01-01

    Foliar carbon isotope composition (δ13C),total dry biomass,and long-term water use efficiency (WUEL)of 12 Populus deltoids clones were studied under water stress in a greenhouse.Total dry biomass of clones decreased greatly,while δ13C increased.Single-element variance analysis in the same water treatment indicated that WUEL difference among clones was significant.Clones J2,J6,J7,J8,and J9 were excellent with high WUEL.Extremely significant δ13C differences among water treatments and clones were revealed by two-element variance analysis.Water proved to be the primary factor affecting δ13C under water stress.It showed that there was a good positive correlation between δ13C and WUEL in the same water treatment,and that a high WUEL always coincided with a high δ13C.δ13C might be a reliable indirect index to estimate WUEL among P.deltoids clones.

  19. Use of carbon-13 as a population marker for Anopheles arabiensis in a sterile insect technique (SIT) context

    OpenAIRE

    Knols Bart GJ; Mayr Leo; Hood-Nowotny Rebecca

    2006-01-01

    Abstract Background Monitoring of sterile to wild insect ratios in field populations can be useful to follow the progress in genetic control programmes such as the Sterile Insect Technique (SIT). Of the numerous methods for marking insects most are not suitable for use in mass rearing and mass release. Suitable ones include dye marking, genetic marking and chemical marking. Methods The feasibility of using the stable isotope of carbon, 13C, as a potential chemical marker for Anopheles arabien...

  20. Tracing carbon fixation in phytoplankton—compound specific and total 13C incorporation rates

    OpenAIRE

    Grosse, J; van Breugel, P; Boschker, H.T.S.

    2015-01-01

    Measurement of total primary production using 13C incorporation is a widely established tool. However, these bulk measurements lack information about the fate of fixed carbon: the production of major cellular compounds (carbohydrates, amino acids, fatty acids, and DNA/RNA) is affected by for instance nutrient availability as their C:N:P requirements differ. Here, we describe an approach to combine established methods in gas chromatography/isotope ratio mass spectrometry (GC/C-IRMS) and recent...

  1. Synthesis of monoketo and monohydroxy eicosanoic acids and esters with substituents at odd–numbered (3-13 carbons

    Directory of Open Access Journals (Sweden)

    HULYA CELIK

    2002-07-01

    Full Text Available In this study, monoketo and monohydroxy eicosanoic acids and their methyl esters with the position of the substituent on odd numbered carbon atoms from 3 to 13 were synthesized with high purity. Furthermore, the semicarbazone and anilide derivatives of the obtained keto acids were prepared. They were characterized by TLC, IR and 1H-NMR spectroscopy and their physical and chemical properties were established.

  2. Biology and air–sea gas exchange controls on the distribution of carbon isotope ratios (δ13C) in the ocean

    OpenAIRE

    A. Schmittner; Gruber, N.; Mix, A. C.; Key, R.M.; Tagliabue, A.; Westberry, T. K.

    2013-01-01

    Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate processes that control the distribution of δ13C of dissolved inorganic carbon (DIC) in the contemporary and preindustrial ocean. Biological fractionation and the sinking of isotopically light δ13C organic matter from the surface into the interior ocean leads to low δ13CDIC values at depths and in high latitude surface waters and high...

  3. Framework for the analysis of the low-carbon scenario 2020 to achieve the national carbon Emissions reduction target: Focused on educational facilities

    International Nuclear Information System (INIS)

    Since the increase in greenhouse gas emissions has increased the global warming potential, an international agreement on carbon emissions reduction target (CERT) has been formulated in Kyoto Protocol (1997). This study aimed to develop a framework for the analysis of the low-carbon scenario 2020 to achieve the national CERT. To verify the feasibility of the proposed framework, educational facilities were used for a case study. This study was conducted in six steps: (i) selection of the target school; (ii) establishment of the reference model for the target school; (iii) energy consumption pattern analysis by target school; (iv) establishment of the energy retrofit model for the target school; (v) economic and environmental assessment through the life cycle cost and life cycle CO2 analysis; and (vi) establishment of the low-carbon scenario in 2020 to achieve the national CERT. This study can help facility managers or policymakers establish the optimal retrofit strategy within the limited budget from a short-term perspective and the low-carbon scenario 2020 to achieve the national CERT from the long-term perspective. The proposed framework could be also applied to any other building type or country in the global environment

  4. Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent Mytilid fatty acids by 13C-fingerprinting

    Directory of Open Access Journals (Sweden)

    F. Dehairs

    2010-05-01

    Full Text Available Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part of their energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assess their ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S, CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively. 14:0, 15:0, 16:1(n-7c+t and 18:1(n-7c+t PLFA were labeled in the presence of H13CO3- (+H2S and 13CH4, while the 12:0 compound became labeled only in the presence of H13CO3− (+H2S. In contrast, the 16:1(n-9, 16:1(n-8 and (n-6, 18:1(n-8c and (n-7, 20:1(n-7 and 18:2(n-7 PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n-7,15. Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts.

  5. Use of Position-Specific 13C Isotopomers to Examine Central Carbon Metabolism in the Thermophile 'Thermoflexus hugenholtzii'

    Science.gov (United States)

    Thomas, S.; Tamadonfar, K. O.; Dijkstra, P.; Dodsworth, J. A.; Hedlund, B. P.

    2013-12-01

    'Thermoflexus hugenholtzii' is a member of a newly discovered class of Chloroflexi. It is the dominant microorganism in certain hot springs; however, very little is known about its physiology, and it is unable to grow on defined media. In order to examine central carbon metabolism in 'T. hugenholtzii', the genome was annotated for genes encoding enzymes for central carbon metabolism, revealing complete pathways for glycolysis, the tricarboxylic acid (TCA) cycle, and the pentose phosphate pathway (PPP). Isotope experiments were conducted to test predicted activities by adding position-specific carbon-13 (13C)-labeled metabolites of glucose, pyruvate, acetate, TCA metabolites, and amino acids and measuring the production of 13CO2 during exponential growth. Use of these metabolites demonstrated broad heterotrophic activity of 'T. hugenholtzii,' despite its inability to grow on defined media. Use of glucose-U demonstrated an active glycolytic pathway and pyruvate-1 demonstrated the functioning of the pyruvate oxidation pathway after glycolysis. Use of the TCA cycle intermediates citrate and succinate demonstrated an active TCA cycle. Production of CO2 from alanine and cysteine demonstrated oxidation of amino acids. However, lack of activity on glucose-1 failed to reveal an active PPP suggesting 'T. hugenholtzii' may rely on exogenous sources of pentoses for nucleic acid biosynthesis.

  6. Hyaluronic acid-functionalized single-walled carbon nanotubes as tumor-targeting MRI contrast agent

    Directory of Open Access Journals (Sweden)

    Hou L

    2015-07-01

    Full Text Available Lin Hou,* Huijuan Zhang,* Yating Wang, Lili Wang, Xiaomin Yang, Zhenzhong ZhangSchool of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, People’s Republic of China*These authors contributed equally to this workAbstract: A tumor-targeting carrier, hyaluronic acid (HA-functionalized single-walled carbon nanotubes (SWCNTs, was explored to deliver magnetic resonance imaging (MRI contrast agents (CAs targeting to the tumor cells specifically. In this system, HA surface modification for SWCNTs was simply accomplished by amidation process and could make this nanomaterial highly hydrophilic. Cellular uptake was performed to evaluate the intracellular transport capabilities of HA-SWCNTs for tumor cells and the uptake rank was HA-SWCNTs> SWCNTs owing to the presence of HA, which was also evidenced by flow cytometry. The safety evaluation of this MRI CAs was investigated in vitro and in vivo. It revealed that HA-SWCNTs could stand as a biocompatible nanocarrier and gadolinium (Gd/HA-SWCNTs demonstrated almost no toxicity compared with free GdCl3. Moreover, GdCl3 bearing HA-SWCNTs could significantly increase the circulation time for MRI. Finally, to investigate the MRI contrast enhancing capabilities of Gd/HA-SWCNTs, T1-weighted MR images of tumor-bearing mice were acquired. The results suggested Gd/HA-SWCNTs had the highest tumor-targeting efficiency and T1-relaxivity enhancement, indicating HA-SWCNTs could be developed as a tumor-targeting carrier to deliver the CAs, GdCl3, for the identifiable diagnosis of tumor.Keywords: gadolinium, magnetic resonance, SWCNTs, hyaluronic acid, contrast agent

  7. 13C-metabolic flux ratio and novel carbon path analyses confirmed that Trichoderma reesei uses primarily the respirative pathway also on the preferred carbon source glucose

    Directory of Open Access Journals (Sweden)

    Saloheimo Markku

    2009-10-01

    Full Text Available Abstract Background The filamentous fungus Trichoderma reesei is an important host organism for industrial enzyme production. It is adapted to nutrient poor environments where it is capable of producing large amounts of hydrolytic enzymes. In its natural environment T. reesei is expected to benefit from high energy yield from utilization of respirative metabolic pathway. However, T. reesei lacks metabolic pathway reconstructions and the utilization of the respirative pathway has not been investigated on the level of in vivo fluxes. Results The biosynthetic pathways of amino acids in T. reesei supported by genome-level evidence were reconstructed with computational carbon path analysis. The pathway reconstructions were a prerequisite for analysis of in vivo fluxes. The distribution of in vivo fluxes in both wild type strain and cre1, a key regulator of carbon catabolite repression, deletion strain were quantitatively studied by performing 13C-labeling on both repressive carbon source glucose and non-repressive carbon source sorbitol. In addition, the 13C-labeling on sorbitol was performed both in the presence and absence of sophorose that induces the expression of cellulase genes. Carbon path analyses and the 13C-labeling patterns of proteinogenic amino acids indicated high similarity between biosynthetic pathways of amino acids in T. reesei and yeast Saccharomyces cerevisiae. In contrast to S. cerevisiae, however, mitochondrial rather than cytosolic biosynthesis of Asp was observed under all studied conditions. The relative anaplerotic flux to the TCA cycle was low and thus characteristic to respiratory metabolism in both strains and independent of the carbon source. Only minor differences were observed in the flux distributions of the wild type and cre1 deletion strain. Furthermore, the induction of the hydrolytic gene expression did not show altered flux distributions and did not affect the relative amino acid requirements or relative anabolic

  8. Carbon-13 isotope composition of the mean CO2 source in the urban atmosphere of Krakow, southern Poland

    Science.gov (United States)

    Zimnoch, Miroslaw; Jasek, Alina; Rozanski, Kazimierz

    2014-05-01

    Quantification of carbon emissions in urbanized areas constitutes an important part of the current research on the global carbon cycle. As the carbon isotopic composition of atmospheric carbon dioxide can serve as a fingerprint of its origin, systematic observations of δ13CO2 and/or Δ14CO2, combined with atmospheric CO2mixing ratio measurements can be used to better constrain the urban sources of this gas. Nowadays, high precision optical analysers based on absorption of laser radiation in the cavity allow a real-time monitoring of atmospheric CO2 concentration and its 13CO2/12CO2 ratio, thus enabling better quantification of the contribution of different anthropogenic and natural sources of this gas to the local atmospheric CO2load. Here we present results of a 2-year study aimed at quantifying carbon isotopic signature of the mean CO2 source and its seasonal variability in the urban atmosphere of Krakow, southern Poland. The Picarro G2101-i CRDS isotopic analyser system for CO2and 13CO2/12CO2 mixing ratio measurements has been installed at the AGH University of Science and Technology campus in July 2011. Air inlet was located at the top of a 20m tower mounted on the roof of the faculty building (ca. 42m a.g.l.), close to the city centre. While temporal resolution of the analyser is equal 1s, a 2-minute moving average was used for calculations of δ13CO2 and CO2 mixing ratio to reduce measurement uncertainty. The measurements were calibrated against 2 NOAA (National Oceanic and Atmospheric Administration) primary standard tanks for CO2 mixing ratio and 1 JRAC (Jena Reference Air Cylinder) isotope primary standard for δ13C. A Keeling approach based on two-component mass and isotope balance was used to derive daily mean isotopic signatures of local CO2 from individual measurements of δ13CO2 and CO2 mixing ratios. The record covers a 2-year period, from July 2011 to July 2013. It shows a clear seasonal pattern, with less negative and less variable δ13CO2 values

  9. Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 2. Modeling carbon sources, sinks, and δ13C evolution

    Science.gov (United States)

    McMahon, Peter B.; Chapelle, Francis H.

    1991-01-01

    Stable isotope data for dissolved inorganic carbon (DIC), carbonate shell material and cements, and microbial CO2 were combined with organic and inorganic chemical data from aquifer and confining-bed pore waters to construct geochemical reaction models along a flowpath in the Black Creek aquifer of South Carolina. Carbon-isotope fractionation between DIC and precipitating cements was treated as a Rayleigh distillation process. Organic matter oxidation was coupled to microbial fermentation and sulfate reduction. All reaction models reproduced the observed chemical and isotopic compositions of final waters. However, model 1, in which all sources of carbon and electron-acceptors were assumed to be internal to the aquifer, was invalidated owing to the large ratio of fermentation CO2 to respiration CO2 predicted by the model (5–49) compared with measured ratios (two or less). In model 2, this ratio was reduced by assuming that confining beds adjacent to the aquifer act as sources of dissolved organic carbon and sulfate. This assumption was based on measured high concentrations of dissolved organic acids and sulfate in confining-bed pore waters (60–100 μM and 100–380 μM, respectively) relative to aquifer pore waters (from less than 30 μM and 2–80 μM, respectively). Sodium was chosen as the companion ion to organic-acid and sulfate transport from confining beds because it is the predominant cation in confining-bed pore waters. As a result, excessive amounts of Na-for-Ca ion exchange and calcite precipitation (three to four times more cement than observed in the aquifer) were required by model 2 to achieve mass and isotope balance of final water. For this reason, model 2 was invalidated. Agreement between model-predicted and measured amounts of carbonate cement and ratios of fermentation CO2 to respiration CO2 were obtained in a reaction model that assumed confining beds act as sources of DIC, as well as organic acids and sulfate. This assumption was

  10. Multifunctional hybrid-carbon nanotubes: new horizon in drug delivery and targeting.

    Science.gov (United States)

    Mehra, Neelesh Kumar; Jain, Narendra Kumar

    2016-01-01

    Carbon nanotubes (CNTs) have emerged as an intriguing nanotechnological tool for numerous biomedical applications including biocompatible modules for the bioactives delivery ascribed to their unique properties, such as greater loading efficiency, biocompatibility, non-immunogenicity, high surface area and photoluminescence, that make them ideal candidate in pharmaceutical and biomedical science. The design of multifunctional hybrid-CNTs for drug delivery and targeting may differ from the conventional drug delivery system. The conventional nanocarriers have few limitations, such as inappropriate availability of surface-chemical functional groups for conjugation, low entrapment/loading efficiency as well as stability as per ICH guidelines with generally regarded as safe (GRAS) prominences. The multifunctional hybrid-CNTs will sparked and open a new door for researchers, scientist of the pharmaceutical and biomedical arena. This review summarizes the vivid aspects of CNTs like characterization, supramolecular chemistry of CNTs-dendrimer, CNTs-nanoparticles, CNTs-quantum dots conjugate for delivery of bioactives, not discussed so far. PMID:26147085

  11. Effects of functionalization on the targeting site of carbon nanotubes inside cells

    Energy Technology Data Exchange (ETDEWEB)

    Porter, A E; Bendall, J S; Welland, M [UK SuperSTEM, Daresbury Laboratory, Daresbury, Cheshire WA4 4AD (United Kingdom); Gass, M [The Nanoscience Centre, University of Cambridge, 11 J. J. Thompson Avenue, Cambridge CB3 OFF (United Kingdom); Muller, K; Skepper, J [Multiimaging Centre, Department of PDN, Physiology, Development and Neuroscience, Anatomy Building, University of Cambridge, Downing Street, Cambridge CB2 3DY (United Kingdom); Midgley, P, E-mail: a.porter@imperial.ac.u [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2010-07-01

    Functionalized single-walled carbon nanotubes (SWNTs) are currently being investigated for a variety of applications, including contrast agents for medical imaging{sup 1}. However before they can be used commercially it is necessary to assess whether they enter cells, the site they target within the cell and whether they cause any cytotoxicity. Here we characterize uptake of unlabelled, acid-treated, COO{sup -} functionalized SWNTs by human monocyte derived macrophage cells using both low-loss and energy loss spectroscopy and compare our findings to previous work on unpurified SWNTs. The acid-treated SWNTs were less aggregated within cells than unpurified SWNTs. Acid treatment was found to affect the distribution of intracellular SWNTs. Bundles, and also individual acid treated SWNTs, were found frequently inside lysosomes, cytoplasm and also inserting into the plasma membrane whereas unpurified non-functionalised SWNTs entered lysosomes and occasionally the nucleus.

  12. Specific carbon-13 labelling of leucine residues in human growth hormone

    International Nuclear Information System (INIS)

    Biosynthetic human growth hormone specifically 13C-labelled in the carbonyl positions of all 26 leucine residues has been obtained by recombiant DNA techniques using 13C-labelled leucine and an E. coli strain that requires leucine. It is shown that, on the whole, the labelling is specific with no significant mislabelling as would have been the case had the 13C-labelled leucine been metabolized. (au)

  13. Construction of magnetic-carbon-quantum-dots-probe-labeled apoferritin nanocages for bioimaging and targeted therapy

    Science.gov (United States)

    Yao, Hanchun; Su, Li; Zeng, Man; Cao, Li; Zhao, Weiwei; Chen, Chengqun; Du, Bin; Zhou, Jie

    2016-01-01

    Carbon dots (CDs) are one of the most highlighted carbon-based materials for biological applications, such as optical imaging nanoprobes, which are used for labeling cells in cancer treatment mainly due to their biocompatibility and unique optical properties. In this study, gadolinium (Gd)-complex-containing CDs were obtained through a one-step microwave method to develop multimodal nanoprobes integrating the advantages of optical and magnetic imaging. The obtained Gd-CDs exhibited highly fluorescent properties with excellent water solubility and biological compatibility. Natural apoferritin (AFn) nanocages, an excellent drug delivery carrier, are hollow in structure, with their pH-dependent, unfolding–refolding process at pH 2.0 and 7.4. The chemotherapeutic drug doxorubicin (DOX) can be highly effective and encapsulated into AFn cavity. A widely used tumor-targeting molecule, folic acid (FA), functionalized the surface of AFn to obtain an active tumor targeting effect on MCF-7 cells and malignant tumors in mice models. In this study, an AFn nanocarrier encapsulating high concentration of DOX labeled with magnetic and fluorescent Gd-CDs probe was developed. Gd-CDs exhibited a unique green photoluminescence and almost no toxicity compared with free GdCl3. Furthermore, Gd-doped CDs significantly increased the circulation time and decreased the toxicity of Gd3+ in in vitro and in vivo magnetic resonance imaging, which demonstrated that the AFn nanocages labeled with Gd-CD compounds could serve as an excellent T1 contrast agent for magnetic resonance imaging. The self-assembling multifunctional Gd-CDs/AFn (DOX)/FA nanoparticles have a great potential for cancer theranostic applications. PMID:27660437

  14. Complementary constraints from carbon (13C) and nitrogen (15N) isotopes on the glacial ocean's soft-tissue biological pump

    Science.gov (United States)

    Schmittner, A.; Somes, C. J.

    2016-06-01

    A three-dimensional, process-based model of the ocean's carbon and nitrogen cycles, including 13C and 15N isotopes, is used to explore effects of idealized changes in the soft-tissue biological pump. Results are presented from one preindustrial control run (piCtrl) and six simulations of the Last Glacial Maximum (LGM) with increasing values of the spatially constant maximum phytoplankton growth rate μmax, which accelerates biological nutrient utilization mimicking iron fertilization. The default LGM simulation, without increasing μmax and with a shallower and weaker Atlantic Meridional Overturning Circulation and increased sea ice cover, leads to 280 Pg more respired organic carbon (Corg) storage in the deep ocean with respect to piCtrl. Dissolved oxygen concentrations in the colder glacial thermocline increase, which reduces water column denitrification and, with delay, nitrogen fixation, thus increasing the ocean's fixed nitrogen inventory and decreasing δ15NNO3 almost everywhere. This simulation already fits sediment reconstructions of carbon and nitrogen isotopes relatively well, but it overestimates deep ocean δ13CDIC and underestimates δ15NNO3 at high latitudes. Increasing μmax enhances Corg and lowers deep ocean δ13CDIC, improving the agreement with sediment data. In the model's Antarctic and North Pacific Oceans modest increases in μmax result in higher δ15NNO3 due to enhanced local nutrient utilization, improving the agreement with reconstructions there. Models with moderately increased μmax fit both isotope data best, whereas large increases in nutrient utilization are inconsistent with nitrogen isotopes although they still fit the carbon isotopes reasonably well. The best fitting models reproduce major features of the glacial δ13CDIC, δ15N, and oxygen reconstructions while simulating increased Corg by 510-670 Pg compared with the preindustrial ocean. These results are consistent with the idea that the soft-tissue pump was more efficient

  15. Conflict and Coordination Problem of Carbon Tax' Diversity Targets in China-Based on the Tax Optimization Theory%Conflict and Coordination Problem of Carbon Tax' Diversity Targets in China-Based on the Tax Optimization Theory

    Institute of Scientific and Technical Information of China (English)

    Xue Gang

    2011-01-01

    Among all the emission reduction measures, carbon tax is recognized as the most effective way to protect our climate. That is why the Chinese government has recently taken it as a tax reform direction, In the current economic analysis, the design of carbon tax is mostly based on the target to maximize the efficiency However, based on the theory of tax system optimization, we should also consider other policy objectives, such as equity, revenue and cost, and then balance different objectives to achieve the suboptimum reform of carbon tax system in China.

  16. Combining sap flow meas- urement-based canopy stomatal conductance and 13C discrimination to estimate forest carbon assimilation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ping; LU Ping; MA Ling; SUN Guchou; RAO Xingquan; CAI Xian; ZENG Xiaoping

    2005-01-01

    The available methods for studying C uptake of forest and their problems in practices are reviewed, and a new approach to combining sap flow and 13C techniques is proposed in this paper. This approach, obtained through strict mathematic derivation, combines sap flow measurement-based canopy stomatal conductance and 13C discrimination to estimate instantaneous carbon assimilation rate of a forest. Namely the mean canopy stomatal conductance (gc) acquired from accurate measurement of sap flux density is integrated with the relationship between 13C discrimination (() and Ci/Ca (intercellular/ambient CO2 concentrations) and with that between Anet (net photosynthetic rate) and gCO2 (stomatal conductance for CO2) so that a new relation between forest C uptake and ( as well as gc is established. It is a new method of such kind for studying the C exchange between forest and atmosphere based on experimental ecology.

  17. A double-quadrature radiofrequency coil design for proton-decoupled carbon-13 magnetic resonance spectroscopy in humans at 7T

    OpenAIRE

    Serés Roig, Eulalia; Magill, Arthur W.; Donati, Guillaume; Meyerspeer, Martin; Xin, Lijing; Ipek, Ozlem; Gruetter, Rolf

    2015-01-01

    Purpose Carbon-13 magnetic resonance spectroscopy (13C-MRS) is challenging because of the inherent low sensitivity of 13C detection and the need for radiofrequency transmission at the 1H frequency while receiving the 13C signal, the latter requiring electrical decoupling of the 13C and 1H radiofrequency channels. In this study, we added traps to the 13C coil to construct a quadrature-13C/quadrature-1H surface coil, with sufficient isolation between channels to allow simultaneous operation at...

  18. Automated determination of the stable carbon isotopic composition (δ13C) of total dissolved inorganic carbon (DIC) and total nonpurgeable dissolved organic carbon (DOC) in aqueous samples: RSIL lab codes 1851 and 1852

    Science.gov (United States)

    Révész, Kinga M.; Doctor, Daniel H.

    2014-01-01

    The purposes of the Reston Stable Isotope Laboratory (RSIL) lab codes 1851 and 1852 are to determine the total carbon mass and the ratio of the stable isotopes of carbon13C) for total dissolved inorganic carbon (DIC, lab code 1851) and total nonpurgeable dissolved organic carbon (DOC, lab code 1852) in aqueous samples. The analysis procedure is automated according to a method that utilizes a total carbon analyzer as a peripheral sample preparation device for analysis of carbon dioxide (CO2) gas by a continuous-flow isotope ratio mass spectrometer (CF-IRMS). The carbon analyzer produces CO2 and determines the carbon mass in parts per million (ppm) of DIC and DOC in each sample separately, and the CF-IRMS determines the carbon isotope ratio of the produced CO2. This configuration provides a fully automated analysis of total carbon mass and δ13C with no operator intervention, additional sample preparation, or other manual analysis. To determine the DIC, the carbon analyzer transfers a specified sample volume to a heated (70 °C) reaction vessel with a preprogrammed volume of 10% phosphoric acid (H3PO4), which allows the carbonate and bicarbonate species in the sample to dissociate to CO2. The CO2 from the reacted sample is subsequently purged with a flow of helium gas that sweeps the CO2 through an infrared CO2 detector and quantifies the CO2. The CO2 is then carried through a high-temperature (650 °C) scrubber reactor, a series of water traps, and ultimately to the inlet of the mass spectrometer. For the analysis of total dissolved organic carbon, the carbon analyzer performs a second step on the sample in the heated reaction vessel during which a preprogrammed volume of sodium persulfate (Na2S2O8) is added, and the hydroxyl radicals oxidize the organics to CO2. Samples containing 2 ppm to 30,000 ppm of carbon are analyzed. The precision of the carbon isotope analysis is within 0.3 per mill for DIC, and within 0.5 per mill for DOC.

  19. Plasmonic welded single walled carbon nanotubes on monolayer graphene for sensing target protein

    Science.gov (United States)

    Kim, Jangheon; Kim, Gi Gyu; Kim, Soohyun; Jung, Wonsuk

    2016-05-01

    We developed plasmonic welded single walled carbon nanotubes (SWCNTs) on monolayer graphene as a biosensor to detect target antigen molecules, fc fusion protein without any treatment to generate binder groups for linker and antibody. This plasmonic welding induces atomic networks between SWCNTs as junctions containing carboxylic groups and improves the electrical sensitivity of a SWCNTs and the graphene membrane to detect target protein. We investigated generation of the atomic networks between SWCNTs by field-emission scanning electron microscopy and atomic force microscopy after plasmonic welding process. We compared the intensity ratios of D to G peaks from the Raman spectra and electrical sheet resistance of welded SWCNTs with the results of normal SWCNTs, which decreased from 0.115 to 0.086 and from 10.5 to 4.12, respectively. Additionally, we measured the drain current via source/drain voltage after binding of the antigen to the antibody molecules. This electrical sensitivity of the welded SWCNTs was 1.55 times larger than normal SWCNTs.

  20. Phosphatidylserine targets single-walled carbon nanotubes to professional phagocytes in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Nagarjun V Konduru

    Full Text Available Broad applications of single-walled carbon nanotubes (SWCNT dictate the necessity to better understand their health effects. Poor recognition of non-functionalized SWCNT by phagocytes is prohibitive towards controlling their biological action. We report that SWCNT coating with a phospholipid "eat-me" signal, phosphatidylserine (PS, makes them recognizable in vitro by different phagocytic cells - murine RAW264.7 macrophages, primary monocyte-derived human macrophages, dendritic cells, and rat brain microglia. Macrophage uptake of PS-coated nanotubes was suppressed by the PS-binding protein, Annexin V, and endocytosis inhibitors, and changed the pattern of pro- and anti-inflammatory cytokine secretion. Loading of PS-coated SWCNT with pro-apoptotic cargo (cytochrome c allowed for the targeted killing of RAW264.7 macrophages. In vivo aspiration of PS-coated SWCNT stimulated their uptake by lung alveolar macrophages in mice. Thus, PS-coating can be utilized for targeted delivery of SWCNT with specified cargoes into professional phagocytes, hence for therapeutic regulation of specific populations of immune-competent cells.

  1. [Targeting of type IV carbonic anhydrases in Capan-1 human pancreatic duct cells is concomitant of the polarization].

    Science.gov (United States)

    Mairal, A; Fanjul, M; Hollande, E

    1996-01-01

    Carbonic anhydrases II and IV play an essential role in the synthesis and secretion of HCO3- ions in pancreatic duct cells. Secretion of these ions is regulated by the CFTR (cystic fibrosis transmembrane conductance regulator) chloride channel. In the present study, the expression of carbonic anhydrases IV and their targeting to plasma membranes were examined during the growth of human pancreatic duct cells in vitro. Human cancerous pancreatic duct cells of Capan-1 cell line which polarize during their growth were used. We show that: a) these cells express carbonic anhydrases IV continuously during growth in culture, and the expression depends on the stage of growth and the conformation of the cells; b) carbonic anhydrases IV are seen in the cytoplasm in non-polarized cells, but become progressively anchored to plasma membranes as the cells polarize, being targeted to the apical membranes of polarized cells; c) the subcellular distribution of carbonic anhydrases IV indicates that these enzymes are synthetized in rough endoplasmic reticulum and then transported towards the plasma membrane using the classical secretory pathway through the Golgi apparatus. The results indicated that targeting of carbonic anhydrases IV in Capan-1 cells is linked to cellular polarization. PMID:8881572

  2. Carbon sequestration and estimated carbon credit values as measured using 13C labeling and analysis by an optical breath test analyser

    International Nuclear Information System (INIS)

    Full text: Recent developments in optical systems for breath testing have provided a robust, low-cost option for undertaking 13C analysis. Although these systems were initially developed for breath testing for Helicobacter pylori, they have an enormous potential as a soil science research tool. The relatively low cost of the equipment at US$ 15000-25000 is within the research budgets of most institutes or universities. The simplicity of the mechanisms and optical nature mean that the equipment requires relatively low maintenance and minimal training. Thus methods were developed to prepare soil and plant materials for analysis using the breath test analyser. Results that compare the conventional mass spectrometry methods with the breath test analyser will be presented. In combination with simple 13C-plant-labeling techniques it is possible to devise methods for estimating carbon sequestration under different agronomic management practices within a short time frame. This allows an assessment of the carbon credit value of a particular agronomic practice, which can in turn be used by policy makers for decision-making purposes. For a global understanding of the effect of agricultural practices on the carbon cycle data is required from a range of cropping systems and agro-ecological zones. The method and the approach described will allow collection of hard data within a reasonable time frame. (author)

  3. Carbon sequestration and estimated carbon credit values as measured using 13C labelling and analysis by means of an optical breath test analyser.

    Science.gov (United States)

    Hood, R C; Khan, M; Haque, A; Khadir, M; Bonetto, J P; Syamsul, R; Mayr, L; Heiling, M

    2004-05-01

    Recent developments in optical systems (isotope-selective non-dispersive infrared spectrometry) for breath testing have provided a robust, low-cost option for undertaking (13)C analysis. Although these systems were initially developed for breath testing for Helicobacter pylori, they have an enormous potential as a soil science research tool. The relatively low cost of the equipment, US$15,000-25,000, is within the research budgets of most institutes or universities. The simplicity of the mechanisms and optical nature mean that the equipment requires relatively low maintenance and minimal training. Thus methods were developed to prepare soil and plant materials for analysis using the breath test analyser. Results that compare conventional mass spectrometric methods with the breath test analyser will be presented. In combination with simple (13)C-plant-labeling techniques it is possible to devise methods for estimating carbon sequestration under different agronomic management practices within a short time frame. This enables assessment of the carbon credit value of a particular agronomic practice, which can in turn be used by policy makers for decision-making purposes. For global understanding of the effect of agricultural practices on the carbon cycle, data are required from a range of cropping systems and agro-ecological zones. The method and the approach described will enable collection of hard data within a reasonable time. PMID:14963630

  4. Paleocene-Eocene δ13C of marine and terrestrial organic matter: implications for the magnitude of total organic carbon hyperthermal isotope excursions

    Science.gov (United States)

    Sluijs, A.; Dickens, G. R.

    2011-12-01

    A series of "hyperthermals" occurred during the Late Paleocene and Early Eocene (~58-50 Ma). These transient global warming events were characterized by prominent negative excursions in the stable carbon isotope ratios (δ13C) of carbon-bearing phases, and widespread dissolution of deep-sea carbonate; they were almost certainly geologically brief intervals of rapid and massive injection of 13C-depleted carbon into the combined ocean-atmosphere-biosphere system. However, the carbon masses involved remain the source of considerable debate, in part because the carbon isotope excursions (CIEs) are expressed differently, depending on the substrate analyzed and the location. For example, the CIE across the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma), now measured in numerous phases at over 100 locations, ranges between 2 - 8 %, even after discounting sections with truncated records. Three factors might cause individual carbon isotope records to differ in shape and magnitude from changes in the global exogenic carbon cycle during hyperthermal events: (i) Changes in the isotope composition of the proximal carbon source (e.g., DIC); (ii) Changes in isotope fractionation through physiological response to ecological change; and (iii) Changes in the relative abundance of components with different δ13C. All three factors likely influence the magnitude of the CIE in many records across hyperthermal events. Here, we discuss how the third factor impacts the δ13C of total organic carbon (TOC) in a shallow marine sequence. Over the past years, bulk organic δ13C, BIT index and palynomorph records have been published for the late Paleocene-early Eocene interval at IODP Hole 4A on Lomonosov Ridge, Arctic Ocean. These records show a long-term -3 % decrease in TOC and a long-term increase in the proportion of marine organic carbon; they also show a rapid -5.5 % CIE in TOC and the proportion of marine organic carbon across the PETM. After correcting for long-term variations in

  5. Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent Mytilid fatty acids by 13C-fingerprinting

    Directory of Open Access Journals (Sweden)

    F. Dehairs

    2010-09-01

    Full Text Available Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part of their energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assess their ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S, CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively. 14:0; 15:0; 16:0; 16:1(n − 7c+t; 18:1(n − 13c+t and (n − 7c+t; 20:1(n − 7; 20:2(n − 9,15; 18:3(n − 7 and (n − 5,10,13 PLFA were labeled in the presence of H13CO3− (+H2S and 13CH4, while the 12:0 compound became labeled only in the presence of H13CO3− (+H2S. In contrast, the 17:0; 18:0; 16:1(n − 9; 16:1(n − 8 and (n − 6; 18:1(n − 8; and 18:2(n − 7 PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n − 7,15. Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts.

  6. Oxygen-18 and carbon-13 records for the last 14,000 years from lacustrine carbonates of Siling-Co (lake) in the Qinghai-Tibetan Plateau

    Science.gov (United States)

    Morinaga, H.; Itota, C.; Isezaki, N.; Goto, H.; Yaskawa, K.; Kusakabe, M.; Liu, J.; Gu, Z.; Yuan, B.; Cong, S.

    1993-12-01

    To understand paleoenvironmental changes for the central Qinghai-Tibetan plateau, we analyzed stable isotopes of oxygen and carbon from calcium carbonates in a bottom sediment core collected from Siling-Co (lake). Five conventional and two Tandetron Acceleration Mass Spectrometry (TAMS) C-14 dates indicate that the core recovered sediments of the last 14,000 years. Calcium carbonates in the sediments seem to be primary carbonates precipitated chemically in the lake, and not clastic particles from limestones distributed around the lake, because of large variation of isotopic ratios, isotopic covariance since 6,000 yr BP and similarity between dates from total calcium carbonates and organic carbon. Their isotopic composition therefore reflects that of the lake water. We present the following paleoenvironmental history over the last 14,000 years in the central part of the plateau, from secular variations of delta O-18, delta C-13 and CaCO3 content throughout the core: (1) Desiccation was dominant during the latter part of the Last Glacial stage (14,000 to 11,000 yr BP). (2) The Last Glacial stage abruptly terminated at 11,000 yr BP. (3) A temperate and stable climate was dominant from 11,000 to 5,000 yr BP. (4) Climatic conditions fluctuated from 5,000 to the present, including two strong desiccation periods (5,000 to 4,000 yr BP and 3,000 to 2,000 yr BP) and an intermediate period of heavy rainfall (4,000 to 3,000 yr BP). This period is also characterized by a covariant O and C isotopic trend.

  7. Analyzing power measurements for the (. pi. sup + ,. pi. sup 0 ) reaction on a polarized sup 13 C target

    Energy Technology Data Exchange (ETDEWEB)

    Goergen, J.J.

    1991-05-01

    The analyzing powers A{sub y} differential cross sections d{sigma}/d{Omega} for the reaction {sup 13}C({pi}{sup +},{pi}{sup 0}){sup 13}N have been measured for forward scattering angles at an incident pion kinetic energy of T{sub pi}{sup +} = 163 MeV by using a transversely polarized target. Analyzing powers and reaction cross sections impose stringent constrains on nuclear reaction models and can be used to test the present understanding of nuclear structure for 1p-shell nuclei. The resulting A{sub y} are compared to the predictions of first-order Distorted Wave Impulse Approximation (DWIA) calculations, which reproduce well the differential cross sections. Although there is qualitative agreement at forward angles, the quantitative agreement is poor, especially at scattering angles larger than 50{degrees}. Since the DWIA calculations do not appear to be strongly sensitive to the assumed nuclear structure model, the discrepancy in describing the analyzing powers suggests that the reaction mechanism may not yet be well understood and higher order corrections may be important. Also measured were the analyzing powers for the elementary charge exchange reaction {pi}{sup {minus}} {bar p} {yields} {pi}{degrees}n over the same angular range and at an incident pion kinetic energy of T{sub pi}{minus} = 161 MeV. The results are compared to the most recents phase shift predictions. Within the experimental uncertainties, phase shift calculations agree with the measured A{sub y} and no changes in the {pi}N phase shifts near the P{sub 33} resonance are needed to describe the data.

  8. Quantitative and mechanistic studies using the oxygen-18 isotope shift in carbon-13 nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mega, T.L.

    1989-01-01

    The {sup 18}O-isotope shift in {sup 13}C NMR spectroscopy was used to study the kinetics of oxygen exchange at the anomeric carbon atoms of several ketoses and aldoses. At 25-26{degree}C and over the pH range from 2 to 10, the relative rates of oxygen exchange for the aldoses studied increased in the following sequence: D-glucose, D-mannose, D-ribose, D-2-deoxyribose. The hydration rates for the open chain forms of the sugars were calculated and the results were analyzed in terms of steric and inductive effects by drawing analogies with the hydration kinetics of simple aldehydes and ketones. Effective molarities associated with ring closure reactions of common monosaccharides are calculated. The position of bond cleavage in the acid-catalyzed hydrolysis of sucrose was elucidated by hydrolyzing the sugar in {sup 18}O-water and assaying the incorporation of {sup 18}O into the several anomeric products using {sup 13}C NMR. Independents supporting experimental evidence was obtained using {sup 1}H NMR. A detailed investigation was made of the complex {sup 13}C NMR spectrum arising from the various {sup 18}O-isotopomers in a solution of {sup 18}O-labeled (1,4-{sup 13}C{sub 2}) succinic acid. The quantitative use of the {sup 18}O isotope shift in {sup 13}C NMR was assessed.

  9. Direct analysis of δ13C and concentration of dissolved organic carbon (DOC) in environmental samples by TOC-IRMS

    Science.gov (United States)

    Kirkels, Frédérique; Cerli, Chiara; Federherr, Eugen; Kalbitz, Karsten

    2014-05-01

    Dissolved organic carbon (DOC) plays an important role in carbon cycling in terrestrial and aquatic systems. Stable isotope analysis (delta 13C) of DOC could provide valuable insights in its origin, fluxes and environmental fate. Precise and routine analysis of delta 13C and DOC concentration are therefore highly desirable. A promising, new system has been developed for this purpose, linking a high-temperature combustion TOC analyzer trough an interface with a continuous flow isotope ratio mass spectrometer (Elementar group, Hanau, Germany). This TOC-IRMS system enables simultaneous stable isotope (bulk delta 13C) and concentration analysis of DOC, with high oxidation efficiency by high-temperature combustion for complex mixtures as natural DOC. To give delta 13C analysis by TOC-IRMS the necessary impulse for broad-scale application, we present a detailed evaluation of its analytical performance for realistic and challenging conditions inclusive low DOC concentrations and environmental samples. High precision (standard deviation, SD predominantly memory effects, no concentration/volume effects and a wide linearity. Low DOC concentrations (highlighted by automated, online analysis, a variable injection volume, high throughput and no extensive maintenance. Sample analysis is simple, using small aliquots and with minimal sample preparation. Further investigations should focus on complex, saline matrices and very low DOC concentrations, to achieve a potential lower limit of 0.2 mgC/L. High-resolution, routine delta 13C analysis of DOC by TOC-IRMS offers opportunities for wide-scale application in terrestrial, freshwater and marine research to elucidate the role of DOC in biogeochemical processes and ecosystem functioning.

  10. Pathway analysis using (13) C-glycerol and other carbon tracers reveals a bipartite metabolism of Legionella pneumophila.

    Science.gov (United States)

    Häuslein, Ina; Manske, Christian; Goebel, Werner; Eisenreich, Wolfgang; Hilbi, Hubert

    2016-04-01

    Amino acids represent the prime carbon and energy source for Legionella pneumophila, a facultative intracellular pathogen, which can cause a life-threatening pneumonia termed Legionnaires' disease. Genome, transcriptome and proteome studies indicate that L. pneumophila also utilizes carbon substrates other than amino acids. We show here that glycerol promotes intracellular replication of L. pneumophila in amoeba or macrophages (but not extracellular growth) dependent on glycerol-3-phosphate dehydrogenase, GlpD. An L. pneumophila mutant strain lacking glpD was outcompeted by wild-type bacteria upon co-infection of amoeba, indicating an important role of glycerol during infection. Isotopologue profiling studies using (13) C-labelled substrates were performed in a novel minimal defined medium, MDM, comprising essential amino acids, proline and phenylalanine. In MDM, L. pneumophila utilized (13) C-labelled glycerol or glucose predominantly for gluconeogenesis and the pentose phosphate pathway, while the amino acid serine was used for energy generation via the citrate cycle. Similar results were obtained for L. pneumophila growing intracellularly in amoeba fed with (13) C-labelled glycerol, glucose or serine. Collectively, these results reveal a bipartite metabolism of L. pneumophila, where glycerol and carbohydrates like glucose are mainly fed into anabolic processes, while serine serves as major energy supply. PMID:26691313

  11. Utilization of carbon 13-labelled stable isotopes for studying drug toxicity on cellular metabolism; Utilisation d`isotopes stables marques au carbone 13 pour etudier la toxicite de drogues au niveau du metabolisme cellulaire

    Energy Technology Data Exchange (ETDEWEB)

    Herve, M.; Wietzerbin, J.; Tran-Dinh, S. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Biologie Cellulaire et Moleculaire

    1994-12-31

    A new approach for studying the effects of two drugs, amphotericine B (AMB), an anti-fungal antibiotic, and 2-deoxy-D-glucose (DG), on the glucose metabolism in brewer yeast cells (Saccharomyces cerevisiae), is presented; AMB interacts with the membrane sterols, inducing formation of pores through which ions and small molecules can pass. DG may enter in the cytosol, where it is phosphoryled by hexokinase into deoxy-D-glucose 6-phosphate (DG6P) which disappears very slowly. DG slows down the glycolysis process and induces the formation of new substances. This paper shows the advantages of utilizing carbon 13-labelled substrates combined to the NMR-13C and NMR-1H techniques. 6 figs., 5 refs.

  12. Preparation and physico-chemical study of nitroxide radicals. Isotopic marking with carbon 13 and deuterium; Preparations et etudes physico-chimiques de radicaux nitroxydes. Marquage isotopique au carbone 13 et au deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Chapelet-Letourneux, G. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-07-01

    N-t-butyl-N-phenyl nitroxide is obtained by: a) action of t-butyl-magnesium chloride on nitrobenzene, or of phenyl-magnesium bromide on nitro-t-butane, b) oxidation of N-t-butyl-N-phenylhydroxylamine, c) oxidation of N-t-butylaniline. In these latter two cases, it has been possible to isolate the pure radical and to study it using UV, IR and EPR. It decomposes to give N-t-butylaniline and the N-oxide of N-t-butyl-p-quinon-imine. The action of peracids such as p-nitro-perbenzoic or m-chloro-perbenzoic acids on amines or hydroxylamines leads to the formation of stable or unstable nitroxide radicals easily observable by EPR. Finally, with a view to obtaining definite values for the coupling between the free electron of a nitroxide and carbon 13, the preparation of such radicals marked with {sup 13}C in the {alpha} or {beta} position of the nitroxide function has been carried out. The coupling with an {alpha} carbon 13 is negative and does not appear to vary with the spin density on the nitrogen. The interaction with the p nuclei of the nitrogen depends on the nature of the substituents: the two benzyl protons have a hyperfine splitting a{sub H} which is always less than that of the ethyl. On the other hand, the {sup 13}C coupling is greater in the first case. The usually adopted conformations for the compounds having the carbonyl group cannot account for the observed values of the {beta} couplings. (author) [French] Le N-t-butyl-N-phenyl nitroxyde est obtenu par: a) action du chlorure de t-butylmagnesium sur le nitrobenzene, ou du bromure de phenylmagnesium sur le nitro-t-butane, b) oxydation de la N-t-butyl-N-phenylhydroxylamine, c) oxydation de la N-t-butylaniline. Dans ces deux derniers cas, le radical a pu etre isole pur et etudie par UV, IR et RPE. Il se decompose en N-t-butylaniline et N-oxyde de N-t-butyl-p-quinonimine. L'action de peracides (p-nitroperbenzoique ou m-chloroperbenzoique) sur des amines ou des hydroxylamines conduit a des radicaux nitroxydes

  13. Direct uptake of organically derived carbon by grass roots and allocation in leaves and phytoliths: 13C labeling evidence

    Science.gov (United States)

    Alexandre, Anne; Balesdent, Jérôme; Cazevieille, Patrick; Chevassus-Rosset, Claire; Signoret, Patrick; Mazur, Jean-Charles; Harutyunyan, Araks; Doelsch, Emmanuel; Basile-Doelsch, Isabelle; Miche, Hélène; Santos, Guaciara M.

    2016-03-01

    In the rhizosphere, the uptake of low-molecular-weight carbon (C) and nitrogen (N) by plant roots has been well documented. While organic N uptake relative to total uptake is important, organic C uptake is supposed to be low relative to the plant's C budget. Recently, radiocarbon analyses demonstrated that a fraction of C from the soil was occluded in amorphous silica micrometric particles that precipitate in plant cells (phytoliths). Here, we investigated whether and to what extent organically derived C absorbed by grass roots can feed the C occluded in phytoliths. For this purpose we added 13C- and 15N-labeled amino acids (AAs) to the silicon-rich hydroponic solution of the grass Festuca arundinacea. The experiment was designed to prevent C leakage from the labeled nutritive solution to the chamber atmosphere. After 14 days of growth, the 13C and 15N enrichments (13C excess and 15N excess) in the roots, stems and leaves as well as phytoliths were measured relative to a control experiment in which no labeled AAs were added. Additionally, the 13C excess was measured at the molecular level, in AAs extracted from roots and stems and leaves. The net uptake of labeled AA-derived 13C reached 4.5 % of the total AA 13C supply. The amount of AA-derived 13C fixed in the plant was minor but not nil (0.28 and 0.10 % of total C in roots and stems/leaves, respectively). Phenylalanine and methionine that were supplied in high amounts to the nutritive solution were more 13C-enriched than other AAs in the plant. This strongly suggested that part of AA-derived 13C was absorbed and translocated into the plant in its original AA form. In phytoliths, AA-derived 13C was detected. Its concentration was on the same order of magnitude as in bulk stems and leaves (0.15 % of the phytolith C). This finding strengthens the body of evidences showing that part of organic compounds occluded in phytoliths can be fed by C entering the plant through the roots. Although this experiment was done in

  14. Measurement of forest ecosystem-atmosphere exchange of delta-carbon-13--carbon dioxide using Fourier transform infrared spectroscopy and disjunct eddy covariance

    Science.gov (United States)

    Cambaliza, Maria Obiminda L.

    The measurement of the stable isotopic content and isotopic flux of atmospheric carbon dioxide is important for understanding the carbon budget on ecosystem, regional, and global spatial scales. Conventional measurements of the isotopic composition of atmospheric CO2 involve laboratory mass spectrometry analysis of grab samples from the field, which limits the location, collection frequency and throughput of samples. More technologically advanced methods (e.g. tunable diode laser spectroscopy) suffer from interferences with other chemical species. We have developed a new measurement method based on Fourier-transform infrared spectroscopy (FTIR) and disjunct eddy covariance (DEC) for fast, continuous, real-time measurement of the carbon isotopic composition of atmospheric CO2. Molecular absorption is measured in the 2100 to 2500 cm -1 spectral region of the 13CO2 and 12CO2 vibration-rotation bands with concentrations of both isotopologues used to determine delta13C. We demonstrate the capability of this new technique in a managed poplar forest near Boardman, Oregon with measurements during the summers of 2005 and 2006 from a 22-meter tower in a 16-m forest canopy. Long-term calibration using reference gas cylinders yielded field accuracy and precision for the forest measurements of 0.5‰ and 0.8‰, respectively, for the 45-second cycle time between samples. The signature of ecosystem respiration derived from the nighttime vertical profile measurements of CO2-delta13C was --26.6‰, about 2‰ more enriched than the isotopic composition of measured bulk leaf samples from the forest. Ecosystem respired CO 2 was ˜1.6‰ more enriched than soil-respired CO2. A comparison of the FTIR -- DEC total CO2 fluxes against standard eddy covariance measurements showed excellent (10%) agreement. FTIR-DEC measurement of the CO2 isoflux enabled the estimation of the mean carbon isotope ratio of the photosynthetic flux (deltaP). The average deltaP (-24.9‰) was 13C

  15. The impact of subcellular location on the near infrared-mediated thermal ablation of cells by targeted carbon nanotubes

    Science.gov (United States)

    Murali, Vasanth S.; Wang, Ruhung; Mikoryak, Carole A.; Pantano, Paul; Draper, Rockford K.

    2016-10-01

    Single-walled carbon nanotubes (SWNTs) are used in the near infrared (NIR)-mediated thermal ablation of tumor cells because they efficiently convert absorbed NIR light into heat. Despite the therapeutic potential of SWNTs, there have been no published studies that directly quantify how many SWNTs need be associated with a cell to achieve a desired efficiency of killing, or what is the most efficient subcellular location of SWNTs for killing cells. Herein we measured dose response curves for the efficiency of killing correlated to the measured amounts of folate-targeted SWNTs that were either on the surface or within the vacuolar compartment of normal rat kidney cells. Folate-targeted SWNTs on the cell surface were measured after different concentrations of SWNTs in medium were incubated with cells for 30 min at 4 °C. Folate-targeted SWNTs within the vacuolar compartments were measured after cells were incubated with different concentrations of SWNTs in medium for 6 h at 37 °C. It was observed that a SWNT load of ∼13 pg/cell when internalized was sufficient to kill 90% of the cells under standardized conditions of NIR light irradiation. When ∼3.5 pg/cell of SWNTs were internalized within the endosomal/lysosomal compartments, ∼50% of the cells were killed, but when ∼3.5 pg/cell of SWNTs were confined to the cell surface only ∼5% of the cells were killed under the same NIR irradiation conditions. The SWNT subcellular locations were verified using Raman imaging of SWNTs merged with fluorescence images of known subcellular markers. To our knowledge, this is the first time that SWNT amounts at known subcellular locations have been correlated with a dose-normalized efficacy of thermal ablation and the results support the idea that SWNTs confined to the plasma membrane are not as effective in NIR-mediated cell killing as an equivalent amount of SWNTs when internalized within the endosomal/lysosomal vesicles.

  16. Effect of Crop cultivation after Mediterranean maquis on soil carbon stock, δ13C spatial distribution and root turnover

    Science.gov (United States)

    Novara, Agata; Gristina, Luciano; Santoro, Antonino; La Mantia, Tommaso

    2013-04-01

    The aim of this work was investigate the effect of land use change on soil organic carbon (SOC) stock and distribution in a Mediterranean succession. A succession composed by natural vegetation, cactus pear crop and olive grove, was selected in Sicily. The land use change from mediterranena maquis (C3 plant) to cactus pear (C4 plant) lead to a SOC decrease of 65% after 28 years of cultivation, and a further decrease of 14% after 7 years since the land use from cactus pear to olive grove (C3 plant). Considering this exchange and decrease as well as the periods after the land use changes we calculated the mean residence time (MRT) of soil C of different age. The MRT of C under Mediterranean maquis was about 142 years, but was 10 years under cactus pear. Total SOC and δ13 C were measured along the soil profile (0-75cm) and in the intra-rows in order to evaluate the distribution of new and old carbon derived and the growth of roots. After measuring of weight of cactus pear root, an approach was developed to estimate the turnover of root biomass. Knowledge of root turnover and carbon input are important to evaluate the correlation between carbon input accumulation and SOC stock in order to study the ability of C sink of soils with different use and managements.

  17. δ13C chemostratigraphy in the upper Tremadocian through lower Katian (Ordovician carbonate succession of the Siljan district, central Sweden

    Directory of Open Access Journals (Sweden)

    Oliver Lehnert

    2014-12-01

    Full Text Available Based on δ13C data from two drillcores recovered from the Siljan district, we present a first continuous carbon isotope record of the upper Tremadocian–lower Katian limestone succession of central Sweden. New names for some isotopic carbon excursions from the Cambrian–Ordovician boundary through the basal Darriwilian are introduced. The Mora 001 core from the western part of the Siljan impact structure ranges through the Lower–Middle Ordovician, whereas the Solberga 1 core from its eastern part ranges through the Middle–lower Upper Ordovician. Upper Tremadocian and Floian units are extremely condensed and include extensive stratigraphic gaps. Multiple hardgrounds, sometimes with minor karstic overprint, imply recurrent periods of erosion and/or non-deposition. Like in other parts of Sweden, the Dapingian and Darriwilian succession is characterized by a relatively complete sedimentary record and low sedimentation rates.

  18. Characterization of alkyl carbon in forest soils by CPMAS 13C NMR spectroscopy and dipolar dephasing

    Science.gov (United States)

    Kogel-Knabner, I.; Hatcher, P.G.

    1989-01-01

    Samples obtained from forest soils at different stages of decomposition were treated sequentially with chloroform/methanol (extraction of lipids), sulfuric acid (hydrolysis), and sodium chlorite (delignification) to enrich them in refractory alkyl carbon. As revealed by NMR spectroscopy, this treatment yielded residues with high contents of alkyl carbon. In the NMR spectra of residues obtained from litter samples, resonances for carbohydrates are also present, indicating that these carbohydrates are tightly bound to the alkyl carbon structures. During decomposition in the soils this resistant carbohydrate fraction is lost almost completely. In the litter samples the alkyl carbon shows a dipolar dephasing behavior indicative of two structural components, a rigid and a more mobile component. As depth and decomposition increase, only the rigid component is observed. This fact could be due to selective degradation of the mobile component or to changes in molecular mobility during decomposition, e.g., because of an increase in cross linking or contact with the mineral matter of the soil.

  19. Analysis of carbon and nitrogen co-metabolism in yeast by ultrahigh-resolution mass spectrometry applying {sup 13}C- and {sup 15}N-labeled substrates simultaneously

    Energy Technology Data Exchange (ETDEWEB)

    Blank, Lars M. [TU Dortmund University, Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, Dortmund (Germany); RWTH Aachen University, Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology - ABBt, Aachen (Germany); Desphande, Rahul R. [TU Dortmund University, Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, Dortmund (Germany); Michigan State University, Department of Plant Biology, East Lansing, MI (United States); Schmid, Andreas [TU Dortmund University, Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, Dortmund (Germany); Hayen, Heiko [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V, Dortmund (Germany); University of Wuppertal, Department of Food Chemistry, Wuppertal (Germany)

    2012-06-15

    Alternative metabolic pathways inside a cell can be deduced using stable isotopically labeled substrates. One prerequisite is accurate measurement of the labeling pattern of targeted metabolites. Experiments are generally limited to the use of single-element isotopes, mainly {sup 13}C. Here, we demonstrate the application of direct infusion nanospray, ultrahigh-resolution Fourier transform ion cyclotron resonance-mass spectrometry (FTICR-MS) for metabolic studies using differently labeled elemental isotopes simultaneously - i.e., {sup 13}C and {sup 15}N - in amino acids of a total protein hydrolysate. The optimized strategy for the analysis of metabolism by a hybrid linear ion trap-FTICR-MS comprises the collection of multiple adjacent selected ion monitoring scans. By limiting both the width of the mass range and the number of ions entering the ICR cell with automated gain control, sensitive measurements of isotopologue distribution were possible without compromising mass accuracy and isotope intensity mapping. The required mass-resolving power of more than 60,000 is only achievable on a routine basis by FTICR and Orbitrap mass spectrometers. Evaluation of the method was carried out by comparison of the experimental data to the natural isotope abundances of selected amino acids and by comparison to GC/MS results obtained from a labeling experiment with {sup 13}C-labeled glucose. The developed method was used to shed light on the complexity of the yeast Saccharomyces cerevisiae carbon-nitrogen co-metabolism by administering both {sup 13}C-labeled glucose and {sup 15}N-labeled alanine. The results indicate that not only glutamate but also alanine acts as an amino donor during alanine and valine synthesis. Metabolic studies using FTICR-MS can exploit new possibilities by the use of multiple-labeled elemental isotopes. (orig.)

  20. Targeted delivery of docetaxel to the metastatic lymph nodes: A comparison study between nanoliposomes and activated carbon nanoparticles

    Directory of Open Access Journals (Sweden)

    Tiantian Ye

    2015-02-01

    Full Text Available The objective of this study is to compare the targeting ability of activated carbon nanoparticles and nanoliposomes, which are used as carriers for delivering docetaxel (DTX to the metastatic lymph nodes. In this study, we first prepared the DTX-loaded activated carbon nanoparticles (DTX-AC-NPs by modifying the activated carbon with nitric acid oxidation and absorbing DTX in the concentrated nitro-oxide nanocarbon. We then prepared DTX-loaded nanoliposomes (DTX-LPs by the proliposome method. The physiochemical properties of DTX-AC-NPs and DTX-LPs were carefully evaluated in vitro. The metastatic lymph node uptake and the injection site retention were investigated by analyzing the DTX concentration in metastatic lymph nodes and injection sites. The result showed that DTX-AC-NPs and DTX-LPs with suitable and stable physicochemical properties could be used for in vivo lymph node targeting studies. DTX-AC-NPs significantly increased DTX-AUC(0–24 and prolonged DTX-retention in metastatic lymph nodes compared to DTX-LPs and non-modified activate carbon in vivo. This study demonstrated activated carbon nanoparticles may be potential intralymphatic drug delivery system to preferentially target regional metastatic lymph nodes.

  1. Construction of magnetic-carbon-quantum-dots-probe-labeled apoferritin nanocages for bioimaging and targeted therapy

    Directory of Open Access Journals (Sweden)

    Yao HC

    2016-09-01

    Full Text Available Hanchun Yao,1,2 Li Su,1 Man Zeng,1 Li Cao,1 Weiwei Zhao,1 Chengqun Chen,3 Bin Du,1,2 Jie Zhou1,2 1School of Pharmaceutical Sciences, Zhengzhou University, 2Collaborative Innovation Center of Drug Research and Safety Evaluation, Henan Province, 3Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People’s Republic of China Abstract: Carbon dots (CDs are one of the most highlighted carbon-based materials for biological applications, such as optical imaging nanoprobes, which are used for labeling cells in cancer treatment mainly due to their biocompatibility and unique optical properties. In this study, gadolinium (Gd-complex-containing CDs were obtained through a one-step microwave method to develop multimodal nanoprobes integrating the advantages of optical and magnetic imaging. The obtained Gd-CDs exhibited highly fluorescent properties with excellent water solubility and biological compatibility. Natural apoferritin (AFn nanocages, an excellent drug delivery carrier, are hollow in structure, with their pH-dependent, unfolding–refolding process at pH 2.0 and 7.4. The chemotherapeutic drug doxorubicin (DOX can be highly effective and encapsulated into AFn cavity. A widely used tumor-targeting molecule, folic acid (FA, functionalized the surface of AFn to obtain an active tumor targeting effect on MCF-7 cells and malignant tumors in mice models. In this study, an AFn nanocarrier encapsulating high concentration of DOX labeled with magnetic and fluorescent Gd-CDs probe was developed. Gd-CDs exhibited a unique green photoluminescence and almost no toxicity compared with free GdCl3. Furthermore, Gd-doped CDs significantly increased the circulation time and decreased the toxicity of Gd3+ in in vitro and in vivo magnetic resonance imaging, which demonstrated that the AFn nanocages labeled with Gd-CD compounds could serve as an excellent T1 contrast agent for magnetic resonance imaging. The self

  2. Identification of aquatically available carbon from algae through solution-state NMR of whole (13)C-labelled cells.

    Science.gov (United States)

    Akhter, Mohammad; Dutta Majumdar, Rudraksha; Fortier-McGill, Blythe; Soong, Ronald; Liaghati-Mobarhan, Yalda; Simpson, Myrna; Arhonditsis, George; Schmidt, Sebastian; Heumann, Hermann; Simpson, André J

    2016-06-01

    Green algae and cyanobacteria are primary producers with profound impact on food web functioning. Both represent key carbon sources and sinks in the aquatic environment, helping modulate the dissolved organic matter balance and representing a potential biofuel source. Underlying the impact of algae and cyanobacteria on an ecosystem level is their molecular composition. Herein, intact (13)C-labelled whole cell suspensions of Chlamydomonas reinhardtii, Chlorella vulgaris and Synechocystis were studied using a variety of 1D and 2D (1)H/(13)C solution-state nuclear magnetic resonance (NMR) spectroscopic experiments. Solution-state NMR spectroscopy of whole cell suspensions is particularly relevant as it identifies species that are mobile (dissolved or dynamic gels), 'aquatically available' and directly contribute to the aquatic carbon pool upon lysis, death or become a readily available food source on consumption. In this study, a wide range of metabolites and structural components were identified within the whole cell suspensions. In addition, significant differences in the lipid/triacylglyceride (TAG) content of green algae and cyanobacteria were confirmed. Mobile species in algae are quite different from those in abundance in 'classic' dissolved organic matter (DOM) indicating that if algae are major contributors to DOM, considerable selective preservation of minor components (e.g. sterols) or biotransformation would have to occur. Identifying the metabolites and dissolved components within algal cells by NMR permits future studies of carbon transfer between species and through the food chain, whilst providing a foundation to better understand the role of algae in the formation of DOM and the sequestration/transformation of carbon in aquatic environments. PMID:27074782

  3. Carbon-13 magnetic relaxation rates or iron (III) complexes of some biogenic amines and parent compounds in aqueous solutions

    International Nuclear Information System (INIS)

    Spin-lattice relaxation rates (R1) from naturally occuring C-13 F.T. N.M.R. spectra of some catecholamines and parent compounds with Iron(III) at pD = 4 were determined in order to elucidate the molecular mechanism underlying their association in aqueous solutions. Complexation was observed only for catecholic ligands. The R1 values were used to calculate iron-carbon scaled distances, and two complexation models were proposed where the catecholic function binds Fe(III) in the first and second coordination spheres respectively. The latter case was shown to be the consistent with the molecular geometries. (orig.)

  4. Carbon dioxide and nitrogen adsorption on cation-exchanged SSZ-13 zeolites.

    Science.gov (United States)

    Pham, Trong D; Liu, Qingling; Lobo, Raul F

    2013-01-15

    Samples of high-silica SSZ-13, ion exchanged with protons and alkali-metal cations Li(+), Na(+), and K(+), were investigated using adsorption isotherms of CO(2) and N(2). The results show that Li-, Na-SSZ-13 have excellent CO(2) capacity at ambient temperature and pressure; in general, Li-SSZ-13 shows the highest capacity for N(2), CO(2) particularly in the low-pressure region. The effect of cation type and Si/Al ratio (6 and 12) on the adsorption properties was investigated through analysis of adsorption isotherms and heats of adsorption. The separation of CO(2) in a flue gas mixture was evaluated for these adsorbents in the pressure swing adsorption and vacuum pressure adsorption processes. PMID:23249267

  5. Investigation on carbon dioxide corrosion behaviour of HP13Cr110 stainless steel in simulated stratum water

    Energy Technology Data Exchange (ETDEWEB)

    Mu, L.J. [School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)], E-mail: mulijunxjtu@126.com; Zhao, W.Z. [School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2010-01-15

    The carbon dioxide corrosion behaviour of HP13Cr110 stainless steel in simulated stratum water is studied by potentiodynamic curve and electrochemical impedance spectroscopy (EIS); the micro-structure and composition of the corrosion scale formed at high-temperature and high-pressure are analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that 13Cr stainless steel is in passive state in the stratum water, the passive current density increases and the passive potential region decreases with increasing temperature. The corrosion scale formed at high-temperature and high-pressure is mainly composed of iron/chromium oxides and a little amount of FeCO{sub 3}.

  6. Effective Prevention of Liver Fibrosis by Liver-targeted Hydrodynamic Gene Delivery of Matrix Metalloproteinase-13 in a Rat Liver Fibrosis Model.

    Science.gov (United States)

    Abe, Hiroyuki; Kamimura, Kenya; Kobayashi, Yuji; Ohtsuka, Masato; Miura, Hiromi; Ohashi, Riuko; Yokoo, Takeshi; Kanefuji, Tsutomu; Suda, Takeshi; Tsuchida, Masanori; Aoyagi, Yutaka; Zhang, Guisheng; Liu, Dexi; Terai, Shuji

    2016-01-01

    Liver fibrosis is the final stage of liver diseases that lead to liver failure and cancer. While various diagnostic methods, including the use of serum marker, have been established, no standard therapy has been developed. The objective of this study was to assess the approach of overexpressing matrix metalloproteinase-13 gene (MMP13) in rat liver to prevent liver fibrosis progression. A rat liver fibrosis model was established by ligating the bile duct, followed by liver-targeted hydrodynamic gene delivery of a MMP13 expression vector, containing a CAG promoter-MMP13-IRES-tdTomato-polyA cassette. After 14 days, the serum level of MMP13 peaked at 71.7 pg/ml in MMP13-treated group, whereas the nontreated group only showed a level of ~5 pg/ml (P sirius red showed a statistically larger volume of fibrotic tissue in the nontreated group compared to that of MMP13-treated rats (P < 0.05). These results suggest that the liver-targeted hydrodynamic delivery of MMP13 gene could be effective in the prevention of liver fibrosis. PMID:26730813

  7. Application of δ13C and δ15N isotopic signatures of organic matter fractions sequentially separated from adjacent arable and forest soils to identify carbon stabilization mechanisms

    OpenAIRE

    Kayler, Z.E.; Kaiser, M; Gessler, A.; Ellerbrock, R. H.; M. Sommer

    2011-01-01

    Identifying the chemical mechanisms behind soil carbon bound in organo-mineral complexes is necessary to determine the degree to which soil organic carbon is stabilized belowground. Analysis of δ13C and δ15N isotopic signatures of stabilized OM fractions along with soil mineral characteristics may yield important information about OM-mineral associations and their processing history. We anlayzed the δ13C and δ15N isotopic signatures from two organic matter (OM) fractio...

  8. Seasonal and interannual variability in 13C composition of ecosystem carbon fluxes in the U.S. Southern Great Plains

    Energy Technology Data Exchange (ETDEWEB)

    Torn, Margaret S. (Lawrence Berkeley National Laboratory and UC Berkeley, Berkeley (United States)), e-mail: mstorn@lbl.gov; Biraud, Sebastien C.; Riley, William J. (Lawrence Berkeley National Laboratory, Earth Sciences Division (United States)); Still, Christopher J. (Univ. of California, Santa Barbara, Geography Dept. (United States)); Berry, Joe A. (Carnegie Institution of Washington, Dept. of Global Ecology (United States))

    2011-04-15

    The delta13C value of terrestrial CO{sub 2} fluxes (delta{sub bio}) provides important information for inverse models of CO{sub 2} sources and sinks as well as for studies of vegetation physiology, C3 and C4 vegetation fluxes, and ecosystem carbon residence times. From 2002-2009, we measured atmospheric CO{sub 2} concentration and delta13C-CO{sub 2} at four heights (2 to 60 m) in the U.S. Southern Great Plains (SGP) and computed delta{sub bio} weekly. This region has a fine-scale mix of crops (primarily C3 winter wheat) and C4 pasture grasses. delta{sub bio} had a large and consistent seasonal cycle of 6.8 per mille. Ensemble monthly mean delta{sub bio} ranged from -25.8 +- 0.4 per mille (+-SE) in March to -20.1 +- 0.4 per mille in July. Thus, C{sub 3} vegetation contributed about 80% of ecosystem fluxes in winter-spring and 50% in summer-fall. In contrast, prairie-soil delta13{sub C} values were about -15 indicating that historically the region was dominated by C{sub 4} vegetation and had more positive deltabio values. Based on a land-surface model, isofluxes (deltabio x NEE) in this region have large seasonal amplitude because deltabio and net ecosystem exchange (NEE) covary. Interannual variability in isoflux was driven by variability in NEE. The large seasonal amplitude in deltabio and isoflux imply that carbon inverse analyses require accurate estimates of land cover and temporally resolved 13CO{sub 2} and CO{sub 2} fluxes

  9. Seasonal and interannual variability in 13C composition of ecosystem carbon fluxes in the U.S. Southern Great Plains

    Science.gov (United States)

    Torn, Margaret S.; Biraud, Sebastien C.; Still, Christopher J.; Riley, William J.; Berry, Joe A.

    2011-04-01

    The δ13C value of terrestrial CO2 fluxes (δbio) provides important information for inverse models of CO2 sources and sinks as well as for studies of vegetation physiology, C3 and C4 vegetation fluxes, and ecosystem carbon residence times. From 2002-2009, we measured atmospheric CO2 concentration and δ13C-CO2 at four heights (2 to 60 m) in the U.S. Southern Great Plains (SGP) and computed δbio weekly. This region has a fine-scale mix of crops (primarily C3 winter wheat) and C4 pasture grasses. δbio had a large and consistent seasonal cycle of 6-8‰. Ensemble monthly mean δbio ranged from -25.8 ± 0.4‰ (±SE) in March to -20.1 ± 0.4‰ in July. Thus, C3 vegetation contributed about 80% of ecosystem fluxes in winter-spring and 50% in summer-fall. In contrast, prairie-soil δ13C values were about -15‰, indicating that historically the region was dominated by C4 vegetation and had more positive δbio values. Based on a land-surface model, isofluxes (δbio× NEE) in this region have large seasonal amplitude because δbio and net ecosystem exchange (NEE) covary. Interannual variability in isoflux was driven by variability in NEE. The large seasonal amplitude in δbio and isoflux imply that carbon inverse analyses require accurate estimates of land cover and temporally resolved 13CO2 and CO2 fluxes.

  10. Gemcitabine-loaded smart carbon nanotubes for effective targeting to cancer cells.

    Science.gov (United States)

    Singh, Ravendra; Mehra, Neelesh Kumar; Jain, Vikas; Jain, Narendra Kumar

    2013-07-01

    Carbon nanotubes (CNTs) are the three-dimensional sp(2) hybridized nano-containers that have attracted considerable interest in drug delivery by offering potential advantages such as biocompatibility, non-immunogenicity, high loading efficiency, intrinsic stability and low toxicities. The aim of the present investigation was to assess the potential of gemcitabine-loaded folic acid (FA) conjugated multi-walled CNTs (GEM/FA-NT) for targeting to breast cancer cells. Pristine MWCNTs was functionalized by FA followed by carboxylation, acylation and amidation and characterized by electron microscopy, FT-IR spectroscopy, X-ray diffraction, entrapment efficiency, cytotoxicity and in vivo studies. FDA-approved GEM was loaded to the purified (GEM-NT) and GEM/FA-NT, and % entrapment efficiency was found to be approximately 71.60 ± 0.25 and 79.60 ± 0.45, respectively. The developed formulation GEM/FA-NT was found to have significantly less hemolytic toxicity (8.23 ± 0.65) as compared to free GEM (17.34 ± 0.56). The in vitro release was found to be in sustained pattern at the lysosomal pH, which depicts more cytotoxic response on human breast cancer cell line (MCF-7). It may be interpreted that the GEM/FA-NT formulation is capable to carry drug and deliver it selectively at the tumor site while minimizing side effects and thus holds promise in chemotherapy.

  11. Targeting single-walled carbon nanotubes for the treatment of breast cancer using photothermal therapy

    Science.gov (United States)

    Neves, Luís F. F.; Krais, John J.; Van Rite, Brent D.; Ramesh, Rajagopal; Resasco, Daniel E.; Harrison, Roger G.

    2013-09-01

    This paper focuses on the targeting of single-walled carbon nanotubes (SWNTs) for the treatment of breast cancer with minimal side effects using photothermal therapy. The human protein annexin V (AV) binds specifically to anionic phospholipids expressed externally on the surface of tumour cells and endothelial cells that line the tumour vasculature. A 2 h incubation of the SWNT-AV conjugate with proliferating endothelial cells followed by washing and near-infrared (NIR) irradiation at a wavelength of 980 nm was enough to induce significant cell death; there was no significant cell death with irradiation or the conjugate alone. Administration of the same conjugate i.v. in BALB/c female mice with implanted 4T1 murine mammary at a dose of 0.8 mg SWNT kg-1 and followed one day later by NIR irradiation of the tumour at a wavelength of 980 nm led to complete disappearance of implanted 4T1 mouse mammary tumours for the majority of the animals by 11 days since the irradiation. The combination of the photothermal therapy with the immunoadjuvant cyclophosphamide resulted in increased survival. The in vivo results suggest the SWNT-AV/NIR treatment is a promising approach to treat breast cancer.

  12. Indazole, Pyrazole, and Oxazole Derivatives Targeting Nitric Oxide Synthases and Carbonic Anhydrases.

    Science.gov (United States)

    Maccallini, Cristina; Di Matteo, Mauro; Vullo, Daniela; Ammazzalorso, Alessandra; Carradori, Simone; De Filippis, Barbara; Fantacuzzi, Marialuigia; Giampietro, Letizia; Pandolfi, Assunta; Supuran, Claudiu T; Amoroso, Rosa

    2016-08-19

    Nitric oxide (NO) is an essential endogenous mediator with a physiological role in the central nervous system as neurotransmitter and neuromodulator. A growing number of studies have demonstrated that abnormal nitrergic signaling is a crucial event in the development of neurodegeneration. In particular, the uncontrolled production of NO by neuronal nitric oxide synthase (nNOS) is observed in several neurodegenerative diseases. Moreover, it is well recognized that specific isoforms of human carbonic anhydrase (hCA) physiologically modulate crucial pathways of signal processing and that low expression of CA affects cognition, leading to mental retardation, Alzheimer's disease, and aging-related cognitive impairments. In light of this, dual agents that are able to target both NOS (inhibition) and CA (activation) could be useful drug candidates for the treatment of Alzheimer's disease, aging, and other neurodegenerative diseases. In the present work, we show the design, synthesis, and in vitro biological evaluation of new nitrogen-based heterocyclic compounds. Among the tested molecules, 2-amino-3-(4-hydroxyphenyl)-N-(1H-indazol-5-yl)propanamide hydrochloride (10 b) was revealed to be a potent dual agent, able to act as a selective nNOS inhibitor and activator of the hCA I isoform. PMID:27377568

  13. Targeting carbonic anhydrase IX by nitroimidazole based sulfamides enhances the therapeutic effect of tumor irradiation: A new concept of dual targeting drugs

    International Nuclear Information System (INIS)

    Background and purpose: Carbonic anhydrase IX (CAIX) plays an important role in pH regulation processes critical for tumor cell growth and metastasis. We hypothesize that a dual targeting bioreductive nitroimidazole based anti-CAIX sulfamide drug (DH348) will reduce tumor growth and sensitize tumors to irradiation in a CAIX dependent manner. Material and methods: The effect of the dual targeting anti-CAIX (DH348) and its single targeting control drugs on extracellular acidification and radiosensitivity was examined in HT-29 colorectal carcinoma cells. Tumor growth and time to reach 4× start volume (T4×SV) was monitored for animals receiving DH348 (10 mg/kg) combined with tumor single dose irradiation (10 Gy). Results: In vitro, DH348 reduced hypoxia-induced extracellular acidosis, but did not change hypoxic radiosensitivity. In vivo, DH348 monotherapy decreased tumor growth rate and sensitized tumors to radiation (enhancement ratio 1.50) without systemic toxicity only for CAIX expressing tumors. Conclusions: A newly designed nitroimidazole and sulfamide dual targeting drug reduces hypoxic extracellular acidification, slows down tumor growth at nontoxic doses and sensitizes tumors to irradiation all in a CAIX dependent manner, suggesting no “off-target” effects. Our data therefore indicate the potential utility of a dual drug approach as a new strategy for tumor-specific targeting

  14. [Impact of land use change and cultivation measures on soil organic carbon (SOC) and its 13C values].

    Science.gov (United States)

    Meng, Fan-qiao; Kuang, Xing; Du, Zhang-liu; Wu, Wen-liang; Guo, Yan-bin

    2010-08-01

    In Quzhou County, Hebei Province where now intensive farming system is operated, original grassland and farming land under different tillage, crop straw return and fertilization measures were studied using isotope carbon for the analysis of the impact on soil organic carbon (SOC) properties. The research indicated that after change into farmland (34 years), SOC is significantly reduced and for 1 m of soil layer, the scope of reduction is from 13.3%-35% and this decrease happens in 0-40 cm of soil layer. After 8 years of fertilization, SOC can be increased at 0.83 g x kg(-1). No-tillage can significantly increase the SOC especially in 0-10 cm but plough will increase the SOC at 10-15 cm and 15-20 cm. Change of delta13 C of SOC due to land use change mainly happens in 0-20 cm, where input of organic materials from maize stored. In soil layer of 0-5 cm, only maximum 18% of SOC is from crop residues and in 15-20 cm, this percentage is about 5%.

  15. Application of low hysteresis carbon black DZ-13 in bias truck tire%低滞后炭黑DZ-13在载重斜交轮胎中的应用

    Institute of Scientific and Technical Information of China (English)

    林浩; 赵冬梅; 程安仁; 万淑霞

    2009-01-01

    研究低滞后炭黑DZ-13在载重斜交轮胎胎面胶和胎肩胶中的应用.结果表明,与采用炭黑N234或N375补强的硫化胶相比,采用低滞后炭黑DZ-13补强的硫化胶弹性模量和回弹值较大,滚动阻力较低,但撕裂强度和抗湿滑性能较差;低滞后炭黑DZ-13更适合用于胎肩胶.%The application of low hysteresis carbon black DZ-13 in tread compound and shoulder compound of bias truck tire was investigated.The results showed that,compared to the vulcanizate reinforced by carbon black N234 or N375,the vulcanizate reinforced by low hysteresis carbon black DZ-13 possessed higher elastic modulus and rebound value,lower rolling resistance,but it also showed poorer tear strength and wet skid resistance;the low hysteresis carbon black DZ-13 was more suitable for the shoulder compound.

  16. Reacting to Greenhouse Gas Emissions: A Carbon Tax to Meet Emission Targets.

    OpenAIRE

    Gilbert Metcalf

    2009-01-01

    In previous papers I have described a revenue and distributionally neutral approach to reducing U.S. greenhouse gas emissions that uses a carbon tax. The revenue from the carbon tax is used to finance an environmental earned income tax credit designed to be distributionally neutral. The carbon tax reform proposal is also revenue neutral and avoids conflating carbon policy with debates over the appropriate size of the federal budget. This paper describes a variant to address concerns of enviro...

  17. Using Atmospheric δ13C of CO2 observations to link the water and carbon cycles with climate

    Science.gov (United States)

    Alden, C. B.; Miller, J. B.; White, J. W.; Yadav, V.; Michalak, A. M.; Andrews, A. E.; Huang, L.

    2013-12-01

    The ratio of stable carbon isotopes, 13C:12C in atmospheric CO2 (expressed as δ13C) offers unique insights into atmosphere-land CO2 fluxes and the modulating effects of stomatal conductance on this exchange. Photosynthesis discriminates against 13CO2 during uptake. The magnitude of this fractionation is strongly dependent upon ambient CO2 concentrations and water availability, as well as on the mix of C3 and C4 vegetation types. C3 and C4 plants have very different discrimination because of carboxylation pathways, and C3 stomatal conductance varies with water availability because stomata close to reduce transpiration when plants are water stressed. Further, plant stomata respond to ambient CO2 concentrations in order to optimize leaf internal [CO2] while reducing transpirative water loss. Atmospheric δ13C therefore carries information about local and upwind drought conditions and the consequent likelihood of ground-to-atmosphere water transfer via transpiration, and the balance of latent and sensible heat fluxes, as well as about local and upwind distributions of C3 and C4 vegetation and variability therein. δ13C offers a unique lens through which to identify key thresholds and relationships between climate anomalies/change and the modulating climate impacts of plant biosphere response. By unraveling this relationship at local to continental scales, we stand to gain crucial understanding of the drivers of land CO2 uptake variability as well as knowledge of how to predict future climate impacts on the carbon cycle and vice versa. We use a two-step Bayesian inversion model to optimize 1x1 degree and 3-hourly (interpreted at regional and weekly to monthly scales) fields of δ13C of assimilated biomass over North America for the year 2010, using influence functions generated with FLEXPART, driven by National Centers for Environmental Prediction Global Forecast System meteorology. Prior fluxes and fossil fuel, ocean and fire fluxes are from CarbonTracker 2011, and

  18. Validation in an animal model of the carbon 13-labeled mixed triglyceride breath test for the detection of intestinal fat malabsorption

    NARCIS (Netherlands)

    Kalivianakis, M; Elstrodt, J; Havinga, R; Kuipers, F; Stellaard, F; Sauer, PJJ; Vonk, RJ; Verkade, HJ

    1999-01-01

    Objective: To determine, in a rat model of fat malabsorption, the potency of the carbon 13-labeled mixed triglyceride (C-13-MTG) breath test as a noninvasive, patient-friendly replacement for classic fat balance studies, Study design: Comparison of the percentage of Fat absorption, detected by fat b

  19. A 1-3 Piezoelectric Fiber Reinforced Carbon Nanotube Composite Sensor for Crack Monitoring

    Science.gov (United States)

    Makireddi, Sai; Balasubramaniam, Krishnan

    2016-07-01

    A method for the detection of location and size of a crack in simple structures using a nanocomposite sensor is discussed. In the present study, a piezoelectric/single walled carbon nanotube composite sensor is modeled on piezoelectric principle. The effective piezoelectric and dielectric properties of the composite at 0.2 volume fraction loading of single walled carbon nanotubes is determined by micromechanical analysis. By means of these effective properties a piezoelectric sensor has been modeled. The transfer function and bode response of this sensor is investigated. The sensor is fixed at a location on a cantilever beam and the response of the sensor with respect to the size and location of the crack is modeled. The analytical values are compared with ANSYS. It is assumed that there is no slippage between the sensor and the beam surface. The sensor behavior with respect to dynamic loading conditions is also studied. It is ascertained that the relative position of the sensor with respect to crack is crucial and determines the sensitivity of the sensor to detect a crack. Results are presented in the form of voltage output from the sensor at different crack locations and at varying lengths of the crack.

  20. A comparison between shell-based δ13C values from an extratropical setting (Gulf of Maine, USA) and atmospheric δ13C values for intervals of the last millennium: insights on regional hydrography and carbon dynamics

    Science.gov (United States)

    Wanamaker, A. D.; Kreutz, K. J.; Introne, D.; Beirne, E. C.

    2010-12-01

    To explore past changes in carbon dynamics in the Gulf of Maine, and to further evaluate the utility of stable carbon isotope ratios (δ13C) derived from the aragonitic shells of the marine bivalve Arctica islandica in global change studies, we compared annual shell δ13C values (N = 4; total of 333 years) with published atmospheric δ13C data (derived from ice cores [AD 1006 to AD 1978; N = 58 measurements] and instrumental series (AD 1981 to AD 2008; total of 28 years]) for intervals of the last millennium. Both datasets were modeled using an exponential function to highlight the low frequency trends in the data and to facilitate a relevant comparison. From AD 1000 to AD 1800, the modeled atmospheric δ13C series increased by 0.20 ‰ (change = 0.00025 ‰ per year), while modeled shell δ13C series decreased by 0.24 ‰ (change = -0.00030 ‰ per year). From AD 1800 to present, both modeled δ13C datasets decreased substantially due to the admixture of isotopically negative carbon derived from increased fossil fuel emissions. The magnitude of the change during this interval in the atmospheric pool was 2.0 ‰ (rate = - 0.0095 ‰ per year), whereas the change in the shell-based values was 1.1 ‰ (rate = - 0.0052 ‰ per year), approximately half of the change noted in the atmosphere. Remarkably, the rate of change in shell δ13C values during the last 200 years was 17 times faster than the previous 800 years. Although the long-term offset (range 8.9 - 8.5 ‰) between atmospheric and shell δ13C data was not constant from AD 1000 to AD 1800, the converging nature of the modeled data suggest that regional hydrographic conditions within the Gulf of Maine during the last millennium have also influenced the δ13C signature in the shells. We will explore some possible hydrographic mechanisms that might explain the divergence between atmospheric and shell-based δ13C values. Despite the noted difference in the atmospheric and shell-based δ13C records, it appears

  1. The influence of temperature and seawater carbonate saturation state on 13C–18O bond ordering in bivalve mollusks

    Directory of Open Access Journals (Sweden)

    R. A. Eagle

    2013-07-01

    Full Text Available The shells of marine mollusks are widely used archives of past climate and ocean chemistry. Whilst the measurement of mollusk δ18O to develop records of past climate change is a commonly used approach, it has proven challenging to develop reliable independent paleothermometers that can be used to deconvolve the contributions of temperature and fluid composition on molluscan oxygen isotope compositions. Here we investigate the temperature dependence of 13C–18O bond abundance, denoted by the measured parameter Δ47, in shell carbonates of bivalve mollusks and assess its potential to be a useful paleothermometer. We report measurements on cultured specimens spanning a range in water temperatures of 5 to 25 °C, and field collected specimens spanning a range of −1 to 29 °C. In addition we investigate the potential influence of carbonate saturation state on bivalve stable isotope compositions by making measurements on both calcitic and aragonitic specimens that have been cultured in seawater that is either supersaturated or undersaturated with respect to aragonite. We find a robust relationship between Δ47 and growth temperature. We also find that the slope of a linear regression through all the Δ47 data for bivalves plotted against seawater temperature is significantly shallower than previously published inorganic and biogenic carbonate calibration studies produced in our laboratory and go on to discuss the possible sources of this difference. We find that changing seawater saturation state does not have significant effect on the Δ47 of bivalve shell carbonate in two taxa that we examined, and we do not observe significant differences between Δ47-temperature relationships between calcitic and aragonitic taxa.

  2. Response of dissolved inorganic carbon (DIC) and δ13CDIC to changes in climate and land cover in SW China karst catchments

    Science.gov (United States)

    Zhao, Min; Liu, Zaihua; Li, Hong-Chun; Zeng, Cheng; Yang, Rui; Chen, Bo; Yan, Hao

    2015-09-01

    Monthly hydrochemical data and δ13C of dissolved inorganic carbon (DIC) in karst water samples from September 2007 to October 2012 were obtained to reveal the controlling mechanisms on DIC geochemistry and δ13CDIC under different conditions of climate and land cover in three karst catchments: Banzhai, Dengzhanhe and Chenqi, in Guizhou Province, SW China. DIC of karst water at the Banzhai site comes mainly from carbonate dissolution under open system conditions with soil CO2 produced by root respiration and organic carbon decomposition with lowest δ13C values under its dense virgin forest coverage. Weaker carbonate bedrock dissolution due to sparse and thin soil cover results in lower δ13CDIC, pCO2, DIC and EC, and lower cation and anion concentrations. At the Chenqi site, larger soil CO2 input from a thick layer of soil results in high pCO2 and DIC, and low pH, SIc and δ13CDIC in the karst water. At the Dengzhanhe site, a lesser soil CO2 input due to stronger karst rock desertification and strong gypsum dissolution contribute to higher δ13CDIC, high EC and high cation and anion concentrations. Soil CO2 inputs, controlled by biological activity and available soil moisture, carbonate bedrock dissolution, dilution and degassing effects, vary seasonally following rainfall and temperature changes. Consequently, there are seasonal cycles in hydrochemistry and δ13CDIC of the karst water, with high pCO2 and low pH, EC, SIc, and δ13CDIC values in the warm and rainy seasons, and vice versa during the cold and dry seasons. A strongly positive shift (>3‰) in δ13CDIC occurred in the drought year, 2011, indicating that δ13CDIC in groundwater systems can be an effective indicator of environmental and/or climate changes.

  3. Theoretical Proof and Empirical Confirmation of a Continuous Labeling Method Using Naturally 13C-Depleted Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Weixin Cheng; Feike A. Dijkstra

    2007-01-01

    Continuous isotope labeling and tracing is often needed to study the transformation, movement, and allocation of carbon in plant-soil systems. However, existing labeling methods have numerous limitations. The present study introduces a new continuous labeling method using naturally 13C-depleted CO2. We theoretically proved that a stable level of 13C-CO2 abundance In a labeling chamber can be maintained by controlling the rate of CO2-free air injection and the rate of ambient airflow with coupling of automatic control of CO2 concentration using a CO2 analyzer. The theoretical results were tested and confirmed in a 54 day experiment in a plant growth chamber. This new continuous labeling method avoids the use of radioactive 14C or expensive 13C-enriched CO2 required by existing methods and therefore eliminates issues of radiation safety or unaffordable isotope cost, as well as creating new opportunities for short- or long-term labeling experiments under a controlled environment.

  4. Carbon Dioxide Clusters: (CO_2)_6 to (CO_2)13

    Science.gov (United States)

    McKellar, A. R. W.; Oliaee, J. Norooz; Dehghany, M.; Moazzen-Ahmadi, N.

    2011-06-01

    We recenty reported assignments of specific infrared bands in the CO_2 νb{3} region (˜2350 wn) to (CO_2)_6, (CO_2)_7, (CO_2)_9, (CO_2)10, (CO_2)11, (CO_2)12, and (CO_2)13. Spectra are obtained by direct absorption using a rapid-scan tuneable diode laser spectrometer to probe a pulsed supersonic slit-jet expansion and assignments are facilitated by recent calculations of Takeuchi based on the Murthy potential. (CO_2)_6 is a symmetric top with S_6 point group symmetry which can be thought of as a stack of two planar cyclic trimers. (CO_2)13 is also an S_6 symmetric top, and consists of a single CO_2 monomer surrounded by an slightly distorted icosahedral cage. The remaining clusters are asymmetric tops without symmetry. Here we report additional CO_2 cluster results. Calculations based on the SAPT-s potential indicate that the structure of (CO_2)10 may be slightly different from that given by Takeuchi/Murthy. An additional band is observed for each of (CO_2)13 and (CO_2)10. A feature observed at 2378.2 wn is assigned as a (CO_2)_6 parallel combination band involving the sum of a fundamental and a low-lying intermolecular vibration. Most significantly, two bands are assigned to a second isomer of (CO_2)_6. This is also a symmetric top, but now with S_4 symmetry. The two symmetric hexamer isomers observed spectroscopically correspond well with the lowest energy structures given by both the SAPT-s and Murthy intermolecular potentials. [1] J. Norooz Oliaee, M. Dehgany, N. Moazzen-Ahmadi, and A.R.W. McKellar, Phys. Chem. Chem. Phys. 13, 1297 (2011). [2] H. Takeuchi, J. Phys. Chem. A 107, 5703 (2008); C.S. Murthy, S.F. O'Shea, and I.R. McDonald, Mol. Phys. 50, 531 (1983). [3] R. Bukowski, J. Sadlej, B. Jeziorski, P. Jankowski, K. Szalewicz, S.A. Kucharski, H.L. Williams, and B.M. Rice, J. Chem. Phys. 110, 3785 (1999)

  5. Can we bet on negative emissions to achieve the 2°C target even under strong carbon cycle feedbacks?

    Science.gov (United States)

    Tanaka, K.; Yamagata, Y.; Yokohata, T.; Emori, S.; Hanaoka, T.

    2015-12-01

    Negative emission technologies such as Bioenergy with Carbon dioxide Capture and Storage (BioCCS) play an ever more crucial role in meeting the 2°C stabilization target. However, such technologies are currently at their infancy and their future penetrations may fall short of the scale required to stabilize the warming. Furthermore, the overshoot in the mid-century prior to a full realization of negative emissions would give rise to a risk because such a temporal but excessive warming above 2°C might amplify itself by strengthening climate-carbon cycle feedbacks. It has not been extensively assessed yet how carbon cycle feedbacks might play out during the overshoot in the context of negative emissions. This study explores how 2°C stabilization pathways, in particular those which undergo overshoot, can be influenced by carbon cycle feedbacks and asks their climatic and economic consequences. We compute 2°C stabilization emissions scenarios under a cost-effectiveness principle, in which the total abatement costs are minimized such that the global warming is capped at 2°C. We employ a reduced-complexity model, the Aggregated Carbon Cycle, Atmospheric Chemistry, and Climate model (ACC2), which comprises a box model of the global carbon cycle, simple parameterizations of the atmospheric chemistry, and a land-ocean energy balance model. The total abatement costs are estimated from the marginal abatement cost functions for CO2, CH4, N2O, and BC.Our preliminary results show that, if carbon cycle feedbacks turn out to be stronger than what is known today, it would incur substantial abatement costs to keep up with the 2°C stabilization goal. Our results also suggest that it would be less expensive in the long run to plan for a 2°C stabilization pathway by considering strong carbon cycle feedbacks because it would cost more if we correct the emission pathway in the mid-century to adjust for unexpectedly large carbon cycle feedbacks during overshoot. Furthermore, our

  6. Insights into the coupling of upper ocean-benthic carbon dynamics in the western Arctic Ocean from an isotopic (13C,234Th) perspective

    Institute of Scientific and Technical Information of China (English)

    ZHANG Run; CHEN Min; MA Qiang; CAO Jianping; QIU Yusheng

    2015-01-01

    The coupling of upper ocean-benthic carbon dynamics in the ice-free western Arctic Ocean (the Chukchi Sea and the Canada Basin) was evaluated during the late July–early September 2003 using natural stable (13C) and radioactive (238U-234Th) isotope tracers. POC export flux estimated from234Th/238U disequilibria and dissolved CO2 concentration ([CO2(aq)]) pointed out that the strengthened biological pump in the Chukchi Shelf have significantly lowered [CO2(aq)] and altered the magnitude of isotopic (12C/13C) fractionation during carbon fixation in the surface ocean. Further,d13C signatures of surface sediments (d13Csed) are positively correlated to those of weightedd13CPOC in upper ocean (d13Csed =13.64+1.56×d13CPOC,r2=0.73,p<0.01), suggesting that the POC isotopic signals from upper ocean have been recorded in the sediments, partly due to the rapid export of particles as evidenced by low residence times of the highly particle-reactive234Th from the upper water column. It is suggested that there probably exists an upper ocean-benthic coupling of carbon dynamics, which likely assures the sedimentaryd13C record an indicator of paleo-CO2 in the western Arctic Ocean.

  7. Spatial variability in photosynthetic and heterotrophic activity drives localized δ13C org fluctuations and carbonate precipitation in hypersaline microbial mats.

    Science.gov (United States)

    Houghton, J; Fike, D; Druschel, G; Orphan, V; Hoehler, T M; Des Marais, D J

    2014-11-01

    Modern laminated photosynthetic microbial mats are ideal environments to study how microbial activity creates and modifies carbon and sulfur isotopic signatures prior to lithification. Laminated microbial mats from a hypersaline lagoon (Guerrero Negro, Baja California, Mexico) maintained in a flume in a greenhouse at NASA Ames Research Center were sampled for δ(13) C of organic material and carbonate to assess the impact of carbon fixation (e.g., photosynthesis) and decomposition (e.g., bacterial respiration) on δ(13) C signatures. In the photic zone, the δ(13) C org signature records a complex relationship between the activities of cyanobacteria under variable conditions of CO2 limitation with a significant contribution from green sulfur bacteria using the reductive TCA cycle for carbon fixation. Carbonate is present in some layers of the mat, associated with high concentrations of bacteriochlorophyll e (characteristic of green sulfur bacteria) and exhibits δ(13) C signatures similar to DIC in the overlying water column (-2.0‰), with small but variable decreases consistent with localized heterotrophic activity from sulfate-reducing bacteria (SRB). Model results indicate respiration rates in the upper 12 mm of the mat alter in situ pH and HCO3- concentrations to create both phototrophic CO2 limitation and carbonate supersaturation, leading to local precipitation of carbonate minerals. The measured activity of SRB with depth suggests they variably contribute to decomposition in the mat dependent on organic substrate concentrations. Millimeter-scale variability in the δ(13) C org signature beneath the photic zone in the mat is a result of shifting dominance between cyanobacteria and green sulfur bacteria with the aggregate signature overprinted by heterotrophic reworking by SRB and methanogens. These observations highlight the impact of sedimentary microbial processes on δ(13) C org signatures; these processes need to be considered when attempting to relate

  8. Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures.

    Science.gov (United States)

    Gu, Shuai; He, Jianqiao; Zhu, Yunlong; Wang, Zhiqiang; Chen, Dongyang; Yu, Guipeng; Pan, Chunyue; Guan, Jianguo; Tao, Kai

    2016-07-20

    The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7-10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m(2) g(-1). By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm(3) g(-1)). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m(2) g(-1)). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g(-1) (at 273 K and 1 bar) and 52 mg g(-1) (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation. PMID:27332739

  9. Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures.

    Science.gov (United States)

    Gu, Shuai; He, Jianqiao; Zhu, Yunlong; Wang, Zhiqiang; Chen, Dongyang; Yu, Guipeng; Pan, Chunyue; Guan, Jianguo; Tao, Kai

    2016-07-20

    The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7-10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m(2) g(-1). By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm(3) g(-1)). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m(2) g(-1)). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g(-1) (at 273 K and 1 bar) and 52 mg g(-1) (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation.

  10. Strong near-infrared carbon in the Type Ia supernova iPTF13ebh

    CERN Document Server

    Hsiao, E Y; Contreras, C; Höflich, P; Sand, D; Marion, G H; Phillips, M M; Stritzinger, M; González-Gaitán, S; Mason, R E; Folatelli, G; Parent, E; Gall, C; Amanullah, R; Anupama, G C; Arcavi, I; Banerjee, D P K; Beletsky, Y; Blanc, G A; Bloom, J S; Brown, P J; Campillay, A; Cao, Y; De Cia, A; Diamond, T; Freedman, W L; Gonzalez, C; Goobar, A; Holmbo, S; Howell, D A; Johansson, J; Kasliwal, M M; Kirshner, R P; Krisciunas, K; Kulkarni, S R; Maguire, K; Milne, P A; Morrell, N; Nugent, P E; Ofek, E O; Osip, D; Palunas, P; Perley, D A; Persson, S E; Piro, A L; Rabus, M; Roth, M; Schiefelbein, J M; Srivastav, S; Sullivan, M; Suntzeff, N B; Surace, J; Woźnia, P R; Yaron, O

    2015-01-01

    We present near-infrared (NIR) time-series spectroscopy, as well as complementary ultraviolet (UV), optical, and NIR data, of the Type Ia supernova (SN Ia) iPTF13ebh, which was discovered within two days from the estimated time of explosion. The first NIR spectrum was taken merely 2.3 days after explosion and may be the earliest NIR spectrum yet obtained of a SN Ia. The most striking features in the spectrum are several NIR C I lines, and the C I {\\lambda}1.0693 {\\mu}m line is the strongest ever observed in a SN Ia. Interestingly, no strong optical C II counterparts were found, even though the optical spectroscopic time series began early and is densely-cadenced. Except at the very early epochs, within a few days from the time of explosion, we show that the strong NIR C I compared to the weaker optical C II appears to be general in SNe Ia. iPTF13ebh is a fast decliner with {\\Delta}m15(B) = 1.79 $\\pm$ 0.01, and its absolute magnitude obeys the linear part of the width-luminosity relation. It is therefore categ...

  11. Access to a polymerase chain reaction assay method targeting 13 respiratory viruses can reduce antibiotics: a randomised, controlled trial

    Directory of Open Access Journals (Sweden)

    Lindh Magnus

    2011-04-01

    Full Text Available Abstract Background Viral respiratory infections are common worldwide and range from completely benign disease to life-threatening illness. Symptoms can be unspecific, and an etiologic diagnosis is rarely established because of a lack of suitable diagnostic tools. Improper use of antibiotics is common in this setting, which is detrimental in light of the development of bacterial resistance. It has been suggested that the use of diagnostic tests could reduce antibiotic prescription rates. The objective of this study was to evaluate whether access to a multiplex polymerase chain reaction (PCR assay panel for etiologic diagnosis of acute respiratory tract infections (ARTIs would have an impact on antibiotic prescription rate in primary care clinical settings. Methods Adult patients with symptoms of ARTI were prospectively included. Nasopharyngeal and throat swabs were analysed by using a multiplex real-time PCR method targeting thirteen viruses and two bacteria. Patients were recruited at 12 outpatient units from October 2006 through April 2009, and samples were collected on the day of inclusion (initial visit and after 10 days (follow-up visit. Patients were randomised in an open-label treatment protocol to receive a rapid or delayed result (on the following day or after eight to twelve days. The primary outcome measure was the antibiotic prescription rate at the initial visit, and the secondary outcome was the total antibiotic prescription rate during the study period. Results A total sample of 447 patients was randomised. Forty-one were excluded, leaving 406 patients for analysis. In the group of patients randomised for a rapid result, 4.5% (9 of 202 of patients received antibiotics at the initial visit, compared to 12.3% (25 of 204 (P = 0.005 of patients in the delayed result group. At follow-up, there was no significant difference between the groups: 13.9% (28 of 202 in the rapid result group and 17.2% (35 of 204 in the delayed result group (P

  12. Acrylic Target Vessels for a High-Precision Measurement of theta13 with the Daya Bay Antineutrino Detectors

    CERN Document Server

    Band, H R; Cherwinka, J; Cao, J; Chang, Y; Edwards, B; He, W; Heeger, K M; Heng, Y; Ho, T; Hsiung, B; Greenler, L; Kettell, S; Lewis, C; Luk, K B; Li, X; Littlejohn, B R; Pagac, A; Wang, C H; Wang, W; Wang, Y; Wise, T; Xiao, Q; Yeh, M; Zhuang, H

    2012-01-01

    This paper describes in detail the acrylic target vessels used to encapsulate the target and gamma catcher regions in the Daya Bay experiment's first pair of antineutrino detectors. We give an overview of the design, fabrication, shipping, and installation of the acrylic target vessels and their liquid overflow tanks. The acrylic quality assurance program and vessel characterization, which measures all geometric, optical, and material properties relevant to {\

  13. Insights Into Water-Soluble Organic Aerosol Sources From Carbon-13 Ratios of Size Exclusion Chromatography Fractions

    Science.gov (United States)

    Ruehl, C. R.; Chuang, P. Y.; McCarthy, M. D.

    2008-12-01

    Many sources of organic aerosols have been identified and quantified, and much of this work has used individual (mosty water-insoluble) compounds as tracers of primary sources. However, most organic aerosol cannot be molecularly characterized, and the water-soluble organic carbon (WSOC) in many aerosols is thought to originate from gaseous precursors (i.e., it is secondary in nature). It can therefore be difficult to infer aerosol sources, particularly of background (i.e., aged) aerosols, and of the relatively high-MW component of aerosols. The stable isotope ratios (δ13C) of organic aerosols have been used to distinguish between sources, with lighter values (-30‰ to -25‰) interpreted as having originated from fossil fuel combustion and C4 biogenic emission, and heavier values (-25‰ to - 20‰) indicating a marine or C3 biogenic source. Most published measurements were of either total suspended particulates or PM2.5, however, and it is unknown to what extent these fractions differ from submicron WSOC. We report δ13C for submicron WSOC collected at a variety of sites, ranging from marine to polluted to background continental. Bulk marine organic δ13C ranged from -30.4 to - 27.6‰, slightly lighter than previously published results. This could be due to the elimination of supermicron cellular material or other biogenic primary emissions from the sample. Continental WSOC δ13C ranged from -19.1 to -29.8‰, with heavier values (-19.8 ± 1.0‰) in Oklahoma and lighter values at Great Smoky Mountain National Park in Tennessee (-25.8 ± 2.6‰) and Illinois (-24.5 ± 1.0‰). This likely results from the greater proportional of C3 plant material in the Oklahoma samples. In addition to bulk samples, we used size exclusion chromatography (SEC) to report δ13C of organic aerosols as a function of hydrodynamic diameter. Variability and magnitude of hydrodynamic diameter was greatest at low SEC pH, indicative of the acidic character of submicron WSOC. Tennessee

  14. Proton, Helium and Carbon Radiation Beam Targeting Reactive Oxygen, Nitrogen and Halogenated Species in TRIM-SRIM Model

    International Nuclear Information System (INIS)

    Nowadays proton beam radiation therapy is considered in few centers for management of malignancies. This study is aimed to explore the effect of proton, helium or carbon irradiation on free radicals. This study was conducted in department of Physiology/Medical physics, College of Medicine, Al-Mustansiriya University in Baghdad, Iraq during October 2009. TRIM-SRIM software version 1998 and2003 were used for computed Bragg peak and for calculated the effect of proton, helium and carbon ions against free radicals related to oxygen, nitrogen and halogen species. The lowest stopping power near Bragg's peak of proton targeting free radicals was against superoxide anion and its curve (the stopping power against energy) was shifted down while that of peroxynitrite(ONOO-) was shifted up. The stopping powers of helium targeting all studied free radicals were lower than corresponding proton irradiation but it required higher energy. Lower stopping power of carbon irradiation targeted hydroxyl(OH-) and halogenated radicals than the other reactive species were observed. It concludes that such from of external beam irradiation is associated with direct scavenging effect on free radicals of whatever sources.

  15. Creation of hierarchical carbon nanotube assemblies through alternative packing of complementary semi-artificial beta-1,3-glucan/carbon nanotube composites.

    Science.gov (United States)

    Numata, Munenori; Sugikawa, Kouta; Kaneko, Kenji; Shinkai, Seiji

    2008-01-01

    Much attention has been focused on exploiting novel strategies for the creation of hierarchical polymer assemblies by the control of the assembling number or the relative location among neighboring polymers. We here propose a novel strategy toward the creation of "hierarchical" single-walled carbon nanotube (SWNT) architectures by utilizing SWNT composites with cationic or anionic complementary semi-artificial beta-1,3-glucans as "building blocks". These beta-1,3-glucans are known to wrap SWNTs helically, to create one-dimensional superstructural composites. If the cationic composite is neutralized by an anionic composite, a well ordered SWNT-based sheet structure was created. Transmission electron microscopy (TEM) observation revealed that this sheet structure is composed of highly-ordered fibrous assemblies of SWNTs. This suggests that the cationic and anionic composites are tightly packed through electrostatic interactions. Moreover, both of the final assembly structures are readily tunable by adjusting the cation/anion ratio. The self-assembling modulation of functional polymers is associated with the progress in ultimate nanotechnologies, thus enabling us to create numerous functional nanomaterials. We believe, therefore, that the present system will extend the frontier of SWNT research to assembly chemistry including "hierarchical" superstructures. PMID:18200640

  16. Novel targets of the CbrAB/Crc carbon catabolite control system revealed by transcript abundance in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Elisabeth Sonnleitner

    Full Text Available The opportunistic human pathogen Pseudomonas aeruginosa is able to utilize a wide range of carbon and nitrogen compounds, allowing it to grow in vastly different environments. The uptake and catabolism of growth substrates are organized hierarchically by a mechanism termed catabolite repression control (Crc whereby the Crc protein establishes translational repression of target mRNAs at CA (catabolite activity motifs present in target mRNAs near ribosome binding sites. Poor carbon sources lead to activation of the CbrAB two-component system, which induces transcription of the small RNA (sRNA CrcZ. This sRNA relieves Crc-mediated repression of target mRNAs. In this study, we have identified novel targets of the CbrAB/Crc system in P. aeruginosa using transcriptome analysis in combination with a search for CA motifs. We characterized four target genes involved in the uptake and utilization of less preferred carbon sources: estA (secreted esterase, acsA (acetyl-CoA synthetase, bkdR (regulator of branched-chain amino acid catabolism and aroP2 (aromatic amino acid uptake protein. Evidence for regulation by CbrAB, CrcZ and Crc was obtained in vivo using appropriate reporter fusions, in which mutation of the CA motif resulted in loss of catabolite repression. CbrB and CrcZ were important for growth of P. aeruginosa in cystic fibrosis (CF sputum medium, suggesting that the CbrAB/Crc system may act as an important regulator during chronic infection of the CF lung.

  17. Use of 13C Labeled Carbon Tetrachloride to Demonstrate the Transformation to Carbon Dioxide under Anaerobic Conditions in a Continuous Flow Column

    Science.gov (United States)

    Semprini, L.; Azizian, M.

    2012-12-01

    The demonstration of transformation of chlorinated aliphatic compounds (CAHs) in the subsurface is a challenge, especially when the products are carbon dioxide (CO2) and chloride ion. The groundwater contaminant carbon tetrachloride (CT) is of particular interest since a broad range of transformation products can be potentially formed under anaerobic conditions. The ability to demonstrate the transformation of CT to CO2 as a non toxic endproduct, is also of great interest. Results will be presented from a continuous flow column study where 13C labeled CT was used to demonstrate its transformation to CO2. The column was packed with a quartz sand and bioaugmented the Evanite Culture (EV) that is capable of transforming tetrachloroethene (PCE) to ethene. The column was continously fed a synthetic groundwater that was amended with PCE (0.10 mM) and either formate (1.5 mM) or lactate (1.1 mM), which ferments to produce hydrogen (H2) as the ultimate electron donor. Earlier CT transformation studies with the column, in the absence of sulfate reduction, and with formate added as a donor found CT (0.015 mM) was over 98% transformed with about 20% converted to chloroform (CF) (0.003 mM) and with a transient detection of chloromethane (CM). Methane and carbon disulfide, as potential products, were not detected. Neither CT nor CF inhibited the reductive dehalogenation of PCE to ethene. A series of transient studies conducted after these initial CT transformation tests, but in the absence of CT, showed formate remained an effective substrate for maintaining sulfate reduction and PCE transformation. Lactate, which was effectively fermented prior to CT addition, was not effectively fermented, with propionate accumulating as a fermentation product. When lactate was added, PCE was mainly transformed to cis-dichloroethene (cis-DCE) and VC, and sulfate reduction did not occur. In order to restore effective lactate fermentation the column was then bioaugmented with an EV culture that

  18. Effects of substrate bias voltage and target sputtering power on the structural and tribological properties of carbon nitride coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Pengfei, E-mail: wangpf@szu.edu.cn [Institute of Nanosurface Science and Engineering, College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen 518060 (China); Institute of Fluid Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Takeno, Takanori [Laboratory of Nanointerface Engineering, Division of Mechanical Engineering, Tohoku University, Aoba 6-6-1, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Fontaine, Julien [Laboratoire de Tribologie et Dynamique des Systèmes, UMR 5513 – CNRS/Ecole Centrale de Lyon, Bâtiment H10, 36 Avenue Guy de Collongue, 69134 Écully Cedex (France); Aono, Masami [Department of Materials Science and Engineering, National Defense Academy, 1-10-20 Hashirimizu, Yokosuka, Kanagawa 239-8686 (Japan); Adachi, Koshi [Laboratory of Nanointerface Engineering, Division of Mechanical Engineering, Tohoku University, Aoba 6-6-1, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Miki, Hiroyuki [Center for Interdisciplinary Research, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Takagi, Toshiyuki [Institute of Fluid Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)

    2014-06-01

    Effects of substrate bias voltage and target sputtering power on the structural and tribological properties of carbon nitride (CN{sub x}) coatings are investigated. CN{sub x} coatings are fabricated by a hybrid coating process with the combination of radio frequency plasma enhanced chemical vapor deposition (RF PECVD) and DC magnetron sputtering at various substrate bias voltage and target sputtering power in the order of −400 V 200 W, −400 V 100 W, −800 V 200 W, and −800 V 100 W. The deposition rate, N/C atomic ratio, and hardness of CN{sub x} coatings as well as friction coefficient of CN{sub x} coating sliding against AISI 52100 pin in N{sub 2} gas stream decrease, while the residual stress of CN{sub x} coatings increases with the increase of substrate bias voltage and the decrease of target sputtering power. The highest hardness measured under single stiffness mode of 15.0 GPa and lowest residual stress of 3.7 GPa of CN{sub x} coatings are obtained at −400 V 200 W, whereas the lowest friction coefficient of 0.12 of CN{sub x} coatings is achieved at −800 V 100 W. Raman and XPS analysis suggest that sp{sup 3} carbon bonding decreases and sp{sup 2} carbon bonding increases with the variations in substrate bias voltage and target sputtering power. Optical images and Raman characterization of worn surfaces confirm that the friction behavior of CN{sub x} coatings is controlled by the directly sliding between CN{sub x} coating and steel pin. Therefore, the reduction of friction coefficient is attributed to the decrease of sp{sup 3} carbon bonding in the CN{sub x} coating. It is concluded that substrate bias voltage and target sputtering power are effective parameters for tailoring the structural and tribological properties of CN{sub x} coatings. - Highlights: • Various CN{sub x} coatings are produced using a unique hybrid coating process. • Structural and tribological properties of CN{sub x} coatings are investigated. • The lowest friction

  19. The Galactic R Coronae Borealis Stars: The C2 Swan Bands, the Carbon Problem, and the 12C/13C Ratio

    Science.gov (United States)

    Hema, B. P.; Pandey, Gajendra; Lambert, David L.

    2012-03-01

    Observed spectra of R Coronae Borealis (RCB) and hydrogen-deficient carbon (HdC) stars are analyzed by synthesizing the C2 Swan bands (1, 0), (0, 0), and (0, 1) using our detailed line list and the Uppsala model atmospheres. The (0, 1) and (0, 0) C2 bands are used to derive the 12C abundance, and the (1, 0) 12C13C band to determine the 12C/13C ratios. The carbon abundance derived from the C2 Swan bands is about the same for the adopted models constructed with different carbon abundances over the range 8.5 (C/He = 0.1%) to 10.5 (C/He = 10%). Carbon abundances derived from C I lines are about a factor of four lower than the carbon abundance of the adopted model atmosphere over the same C/He interval, as reported by Asplund et al., who dubbed the mismatch between adopted and derived C abundance as the "carbon problem." In principle, the carbon abundances obtained from C2 Swan bands and that assumed for the model atmosphere can be equated for a particular choice of C/He that varies from star to star. Then, the carbon problem for C2 bands is eliminated. However, such C/He ratios are in general less than those of the extreme helium stars, the seemingly natural relatives to the RCB and HdC stars. A more likely solution to the C2 carbon problem may lie in a modification of the model atmosphere's temperature structure. The derived carbon abundances and the 12C/13C ratios are discussed in light of the double degenerate and the final flash scenarios.

  20. Bioinformatic analysis of the distribution of inorganic carbon transporters and prospective targets for bioengineering to increase Ci uptake by cyanobacteria.

    Science.gov (United States)

    Gaudana, Sandeep B; Zarzycki, Jan; Moparthi, Vamsi K; Kerfeld, Cheryl A

    2015-10-01

    Cyanobacteria have evolved a carbon-concentrating mechanism (CCM) which has enabled them to inhabit diverse environments encompassing a range of inorganic carbon (Ci: [Formula: see text] and CO2) concentrations. Several uptake systems facilitate inorganic carbon accumulation in the cell, which can in turn be fixed by ribulose 1,5-bisphosphate carboxylase/oxygenase. Here we survey the distribution of genes encoding known Ci uptake systems in cyanobacterial genomes and, using a pfam- and gene context-based approach, identify in the marine (alpha) cyanobacteria a heretofore unrecognized number of putative counterparts to the well-known Ci transporters of beta cyanobacteria. In addition, our analysis shows that there is a huge repertoire of transport systems in cyanobacteria of unknown function, many with homology to characterized Ci transporters. These can be viewed as prospective targets for conversion into ancillary Ci transporters through bioengineering. Increasing intracellular Ci concentration coupled with efforts to increase carbon fixation will be beneficial for the downstream conversion of fixed carbon into value-added products including biofuels. In addition to CCM transporter homologs, we also survey the occurrence of rhodopsin homologs in cyanobacteria, including bacteriorhodopsin, a class of retinal-binding, light-activated proton pumps. Because they are light driven and because of the apparent ease of altering their ion selectivity, we use this as an example of re-purposing an endogenous transporter for the augmentation of Ci uptake by cyanobacteria and potentially chloroplasts.

  1. Land use Effects on Storage, Stability and Structure of Organic Carbon in Soil Density Fractions Revealed by 13C Natural Abundance and CPMAS 13C NMR

    Science.gov (United States)

    Flessa, H.; Helfrich, M.; John, B.; Yamashita, T.; Ludwig, B.

    2004-12-01

    The type of land use and soil cultivation are important factors controlling organic carbon storage (SOC) in soils and they can also influence the relative importance, the structure, and the stability of different SOC pools. The objectives of our study were: i) to quantify the SOC stocks in different density fractions (mineral-associated soil organic matter > 2 g cm-3 (Mineral-SOM), free particulate organic matter soils under different land use (spruce forest, grassland, maize, wheat), ii) to determine the structure of these SOC fractions by CPMAS 13C NMR spectroscopy, and iii) to analyse the stability of these SOC fractions in the maize soil on the basis of the stable isotope composition of SOC. The SOC concentration in the A horizon increased in the order wheat (12.7 g kg-1) soil, the particulate organic matter accounted for 52% of the total SOC content. The chemical structure of the soil organic matter (SOM) was influenced by litter quality, the intensity of litter decomposition and the related production and storage of microbially-derived substances. SOM of the acid forest soil was characterized by large amounts of POM with a high content of spruce litter-derived alkyl C. In the biologically more active grassland and maize soil, litter-derived POM was decomposed more rapidly and SOC stocks were dominated by mineral-associated SOM which contained greater proportions of aryl and carbonyl C. The cultivation of the grassland soil induced enhanced mineralization of POM and in particular of mineral-associated SOM. The faster SOC turnover was associated with a relative accumulation of aromatic and carbonyl C structures in the mineral-bound SOM. In all soils, the free particulate organic matter had a smaller proportion of alkyl C and a larger proportion of O-alkyl C than the particulate organic matter occluded in aggregates. The mean age of the SOM in the density fractions of the maize soil increased with increasing aromaticity in the order free POM (22 yr) humification

  2. Accumulation and δ 13C Composition of Soil Carbon Across a Chronosequence of Dune Complexes at Mono Lake, CA

    Science.gov (United States)

    Aanderud, Z. T.; Shuldman, M. I.; Richards, J. H.

    2004-12-01

    The amount of C sequestered and its permanence in some deserts could be higher than normally appreciated. Limited soil water availability and slow decomposition rates in desert soils may induce the long-term accumulation of soil organic C and coarse woody litter. We inventoried C in soils along a chronosequence of Sarcobatus vermiculatus shrub islands and interspaces at the Mono Basin Ecosystem Research Site, CA. Such shrub-island/interspace dune systems are widespread in basin habitats across the Great Basin Desert. We hypothesized that organic C stores would increase across the chronosequence (48, 84, ˜300, and 1800-3000 years since exposure by lake recession) and that δ 13C values of soil organic C (SOC) would become enriched over time due to isotopic fractionation associated with C mineralization of leaf and root litter. C stores quantified in 0-50 cm soils included: SOC, soil inorganic C (SIC; i.e. carbonates removed by 12 M HCl fumigation), and C in partially decomposed woody and fine litter. The youngest dune system contains at least 13.6 Mg C ha-1 and the oldest contains at least 37.9 Mg C ha-1. Our data suggest slow turnover rates of SOC (C:N ratios ˜10) and substantial accumulation of organic C (coarse litter, fine litter, and SOC) in shrub islands across the chronosequence (islands at the youngest site = 8.0 g kg-1 and islands at the oldest site = 24.0 g kg-1. Large pools of SOC and C in woody debris are potentially protected in this shrub-dominated desert, especially in shrub islands of "old-growth" dune systems. Most of the C in the soil is SIC (94% in youngest dunes to 83% at the oldest dunes). The decrease in SIC proportion as the dune systems age is correlated with a decrease in pH across the chronosequence (10.6 at the youngest site and 9.7 at the oldest site). As dunes age, total soil C isotopic composition shifts from positive δ 13C values (2.8 to 3.6 ‰ ), indicative inorganic processes, to slightly negative values (-1.2 to -3.7 ‰ ) as a

  3. Effects of carbon content and microstructure on corrosion rate of 13% chromium steel in wet CO2 environments; Shitsujun CO2 kankyochu deno 13%Cr ko no fushoku ni oyobosu C ryo to kinzoku soshiki no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Hara, T.; Asahi, H. [Nippon Steel Corp., Tokyo (Japan)

    1998-11-15

    Thirteen percent chromium steel is excellent in corrosion resistance of CO2. A large quantity of 13% chromium steel is used in oil and gas fields where CO2 is produced. Usually, AISI 420 13% chromium steel to which C was added 0.2% is used for an oil field tube. Since AISI 420 steel is tempered, chromium carbide is formed and the effective chromium amount in a parent phase is decreased to deteriorate the corrosion resistance of CO2. Therefore, it is desired to decrease the carbon content as far as possible for improvement of corrosion resistance of CO2. AISI 410 13% chromium steel with a carbon content of 0.1% is difficult to form {delta}-ferrite. It has a problem in manufacturing because the hot working performance is low. In this report, on the basis of AISI 420 13% chromium steel, the effects of composition on CO2 corrosion were investigated using the steel whose carbon content was changed. Ferrite, martensite, and tempered martensite differ in a corrosion rate. The corrosion rate increases in the order of martensite, ferrite, and tempered martensite. The corrosion rate of 13% chromium steel is represented by the product of the corrosion rate of each microstructure and the fraction of it. 11 refs., 12 figs., 2 tabs.

  4. Coupling of a bifunctional peptide R13 to OTMCS-PEI copolymer as a gene vector increases transfection efficiency and tumor targeting

    Directory of Open Access Journals (Sweden)

    Lv H

    2014-03-01

    Full Text Available Hui Lv,1,* Qing Zhu,1,* Kewu Liu,2 Manman Zhu,1 Wenfang Zhao,1 Yuan Mao,1 Kehai Liu1 1Department of Biopharmaceutics, College of Food Science and Technology, Shanghai Ocean University, Shanghai, People's Republic of China; 2Heilongjiang Forest By-Product and Speciality Institute, Mudanjiang, People's Republic of China *These authors contributed equally to this work Background: A degradable polyethylenimine (PEI derivative coupled to a bifunctional peptide R13 was developed to solve the transfection efficiency versus cytotoxicity and tumor-targeting problems of PEI when used as a gene vector. Methods: We crossed-linked low molecular weight PEI with N-octyl-N-quaternary chitosan (OTMCS to synthesize a degradable PEI derivative (OTMCS-PEI, and then used a bifunctional peptide, RGDC-Tat (49–57 called R13 to modify OTMCS-PEI so as to prepare a new gene vector, OTMCS-PEI-R13. This new gene vector was characterized by various physicochemical methods. Its cytotoxicity and gene transfection efficiency were also determined both in vitro and in vivo. Results: The vector showed controlled degradation and excellent buffering capacity. The particle size of the OTMCS-PEI-R13/DNA complexes was around 150–250 nm and the zeta potential ranged from 10 mV to 30 mV. The polymer could protect plasmid DNA from being digested by DNase I at a concentration of 23.5 U DNase I/µg DNA. Further, the polymer was resistant to dissociation induced by 50% fetal bovine serum and 400 µg/mL sodium heparin. Compared with PEI 25 kDa, the OTMCS-PEI-R13/DNA complexes showed higher transfection efficiency both in vitro and in vivo. Further, compared with OTMCS-PEI, distribution of OTMCS-PEI-R13 at tumor sites was markedly enhanced, indicating the tumor-targeting specificity of R13. Conclusion: OTMCS-PEI-R13 could be a potential candidate as a safe and efficient gene delivery carrier for gene therapy. Keywords: nonviral gene vector, polyethylenimine, R13, transfection efficiency

  5. [Distribution characteristics of soil humus fractions stable carbon isotope natural abundance (delta 13C) in paddy field under long-term ridge culture].

    Science.gov (United States)

    Tang, Xiao-hong; Luo, You-jin; Ren, Zhen-jiang; Lü, Jia-ke; Wei, Chao-fu

    2011-04-01

    A 16-year field experiment was conducted in a ridge culture paddy field in the hilly region of Sichuan Basin, aimed to investigate the distribution characteristics of stable carbon isotope natural abundance (delta 13C) in soil humus fractions. The soil organic carbon (SOC) content in the paddy field under different cultivation modes ranked in the order of wide ridge culture > ridge culture > paddy and upland rotation. In soil humus substances (HS), humin (HU) was the main composition, occupying 21% - 30% of the total SOC. In the extracted soil carbon, humic acid (HA) dominated, occupying 17% - 21% of SOC and 38% - 65% of HS. The delta 13C value of SOC ranged from -27.9 per thousand to -25.6 per thousand, and the difference of the delta 13C value between 0-5 cm and 20-40 cm soil layers was about 1.9 per thousand. The delta 13C value of HA under different cultivation modes was 1 per thousand - 2 per thousand lower than that of SOC, and more approached to the delta 13C value of rapeseed and rice residues. As for fulvic acid (FA), its delta 13C value was about 2 per thousand and 4 per thousand higher than that of SOC and HA, respectively. The delta 13C value of HU in plough layer (0-20 cm) and plow layer (20-40 cm) ranged from -23.7 per thousand - -24.9 per thousand and -22.6 per thousand - -24.2 per thousand, respectively, reflecting the admixture of young and old HS. The delta 13C value in various organic carbon fractions was HU>FA>SOC>rapeseed and rice residues>HA. Long-term rice planting benefited the increase of SOC content, and cultivation mode played an important role in affecting the distribution patterns of soil humus delta 13C in plough layer and plow layer.

  6. Targeting single-walled carbon nanotubes for the treatment of breast cancer using photothermal therapy

    Science.gov (United States)

    Neves, Luis Filipe Ferreira

    To develop a therapeutic system with cancer cell selectivity, the present study evaluated a possible specific and localized tumor treatment. Phosphatidylserine (PS) exposure on the external face of the cell membrane is almost completely exclusive to cancer cells and endothelial cells in the tumor vasculature. The human protein annexin V is known to have strong calcium-dependent binding to anionic phospholipids such as PS. This protein was studied for targeting single-walled carbon nanotubes (SWNTs) to the vasculature of breast tumors. The synthesis of the protein annexin V, by a pET vector in Escherichia coli, constitutes the first phase of this study. Recombinant annexin V was purified from the cell lysate supernatant by immobilized metal affinity chromatography. The overall production of purified annexin V protein was 50 mg/L. The binding ability of the protein annexin V was evaluated by determining the dissociation constant when incubated with proliferating human endothelial cells in vitro. The dissociation constant, Kd, was measured to be 0.8 nM, indicating relatively strong binding. This value of Kd is within the range reported in the literature. Single-walled carbon nanotubes (SWNTs) were functionalized with annexin V using two intermediate linkers (containing FMOC and DSPE) resulting in stable suspensions. The SWNT and protein concentrations were 202 mg/L and 515 mg/L, respectively, using the linker with DSPE (average of nine preparations). The conjugation method that used the DSPE-PEG-maleimide linker allowed to successfully conjugate the SWNTs with final concentrations approximately five times higher than the linker containing FMOC. The conjugation method used has a non-covalent nature, and therefore the optical properties of the nanotubes were preserved. The conjugate was also visually observed using atomic force microscopy (AFM), allowing to verify the presence of the protein annexin V on the surface of the nanotubes, with an height ranging between 2

  7. Crystal structures of 2-methoxyisoindoline-1,3-dione, 1,3-dioxoisoindolin-2-yl methyl carbonate and 1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-2-yl methyl carbonate: three anticonvulsant compounds

    Directory of Open Access Journals (Sweden)

    Fortune Ezemobi

    2014-12-01

    Full Text Available The title compounds, C9H7NO3, (1, C10H7NO5, (2, and C14H9NO5, (3, are three potentially anticonvulsant compounds. Compounds (1 and (2 are isoindoline derivatives and (3 is an isoquinoline derivative. Compounds (2 and (3 crystallize with two independent molecules (A and B in their asymmetric units. In all three cases, the isoindoline and benzoisoquinoline moieties are planar [r.m.s. deviations are 0.021 Å for (1, 0.04 and 0.018 Å for (2, and 0.033 and 0.041 Å for (3]. The substituents attached to the N atom are almost perpendicular to the mean planes of the heterocycles, with dihedral angles of 89.7 (3° for the N—O—Cmethyl group in (1, 71.01 (4 and 80.00 (4° for the N—O—C(=OO—Cmethyl groups in (2, and 75.62 (14 and 74.13 (4° for the same groups in (3. In the crystal of (1, there are unusual intermolecular C=O...C contacts of 2.794 (1 and 2.873 (1 Å present in molecules A and B, respectively. There are also C—H...O hydrogen bonds and π–π interactions [inter-centroid distance = 3.407 (3 Å] present, forming slabs lying parallel to (001. In the crystal of (2, the A and B molecules are linked by C—H...O hydrogen bonds, forming slabs parallel to (10-1, which are in turn linked via a number of π–π interactions [the most significant centroid–centroid distances are 3.4202 (7 and 3.5445 (7 Å], forming a three-dimensional structure. In the crystal of (3, the A and B molecules are linked via C—H...O hydrogen bonds, forming a three-dimensional structure, which is consolidated by π–π interactions [the most significant inter-centroid distances are 3.575 (3 and 3.578 (3 Å].

  8. Biology and air–sea gas exchange controls on the distribution of carbon isotope ratios (δ13C in the ocean

    Directory of Open Access Journals (Sweden)

    A. Schmittner

    2013-05-01

    Full Text Available Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate the processes that control the distribution of δ13C in the contemporary and preindustrial ocean. Biological fractionation dominates the distribution of δ13CDIC of dissolved inorganic carbon (DIC due to the sinking of isotopically light δ13C organic matter from the surface into the interior ocean. This process leads to low δ13CDIC values at dephs and in high latitude surface waters and high values in the upper ocean at low latitudes with maxima in the subtropics. Air–sea gas exchange provides an important secondary influence due to two effects. First, it acts to reduce the spatial gradients created by biology. Second, the associated temperature dependent fractionation tends to increase (decrease δ13CDIC values of colder (warmer water, which generates gradients that oppose those arising from biology. Our model results suggest that both effects are similarly important in influencing surface and interior δ13CDIC distributions. However, air-sea gas exchange is slow, so biological effect dominate spatial δ13CDIC gradients both in the interior and at the surface, in constrast to conclusions from some previous studies. Analysis of a new synthesis of δ13CDIC measurements from years 1990 to 2005 is used to quantify preformed (δ13Cpre and remineralized (δ13Crem contributions as well as the effects of biology (Δδ13Cbio and air–sea gas exchange (δ13C*. The model reproduces major features of the observed large-scale distribution of δ13CDIC, δ13Cpre, δ13Crem, δ13C*, and Δδ13Cbio. Residual misfits are documented and analyzed. Simulated surface and subsurface δ13CDIC are influenced by details of the ecosystem model formulation. For example, inclusion of a simple parameterization of iron limitation of phytoplankton growth rates and temperature-dependent zooplankton grazing rates improves the agreement

  9. Targeting carbonic anhydrase to treat diabetic retinopathy: Emerging evidences and encouraging results

    Energy Technology Data Exchange (ETDEWEB)

    Weiwei, Zhang [Department of Endocrinology and Metabolism, HuaShan Hospital, Institute of Endocrinology and Diabetology, Shanghai Medical College, Fudan University, No. 12 Wulumuqi Road, Shanghai 200040 (China); Hu, Renming, E-mail: taylorzww@gmail.com [Department of Endocrinology and Metabolism, HuaShan Hospital, Institute of Endocrinology and Diabetology, Shanghai Medical College, Fudan University, No. 12 Wulumuqi Road, Shanghai 200040 (China)

    2009-12-18

    Diabetic retinopathy (DR) is the leading cause of vision loss among working-age populations in developed countries. Current treatment options are limited to tight glycemic, blood pressure control and destructive laser surgery. Carbonic anhydrases (CAs) are a group of enzymes involving in the rapid conversion of carbon dioxide to bicarbonate and protons. Emerging evidences reveal CA inhibitors hold the promise for the treatment of DR. This article summarizes encouraging results from clinical and animal studies, and reviews the possible mechanisms.

  10. Targeting carbonic anhydrase to treat diabetic retinopathy: Emerging evidences and encouraging results

    International Nuclear Information System (INIS)

    Diabetic retinopathy (DR) is the leading cause of vision loss among working-age populations in developed countries. Current treatment options are limited to tight glycemic, blood pressure control and destructive laser surgery. Carbonic anhydrases (CAs) are a group of enzymes involving in the rapid conversion of carbon dioxide to bicarbonate and protons. Emerging evidences reveal CA inhibitors hold the promise for the treatment of DR. This article summarizes encouraging results from clinical and animal studies, and reviews the possible mechanisms.

  11. Inlfuence of carbon content on microstructure and mechanical properties of Mn13Cr2 and Mn18Cr2 cast steels

    Institute of Scientific and Technical Information of China (English)

    Lu Dingshan; Liu Zhongyi; Li Wei

    2014-01-01

    In this paper, a comparison study was carried out to investigate the inlfuence of carbon content on the microstructure, hardness, and impact toughness of water-quenched Mn13Cr2 and Mn18Cr2 cast steels. The study results indicate that both steels' water-quenched microstructures are composed of austenite and a smal amount of carbide. The study also found that, when the carbon contents are the same, there is less carbide in Mn18Cr2 steel than in Mn13Cr2 steel. Therefore, the hardness of Mn18Cr2 steel is lower than that of Mn13Cr2 steel but the impact toughness of Mn18Cr2 steel is higher than that of Mn13Cr2 steel. With increasing the carbon content, the hardness increases and the impact toughness decreases in these two kinds of steels, and the impact toughness of Mn18Cr2 steel substantialy exceeds that of Mn13Cr2 steel. Therefore, the water-quenched Mn18Cr2 steel with high carbon content could be applied to relatively high impact abrasive working conditions, while the as-cast Mn18Cr2 steel could be only used under working conditions of relatively low impact abrasive load due to lower impact toughness.

  12. MicroRNA-30c-1-3p is a silencer of the pregnane X receptor by targeting the 3'-untranslated region and alters the expression of its target gene cytochrome P450 3A4.

    Science.gov (United States)

    Vachirayonstien, Thaveechai; Yan, Bingfang

    2016-09-01

    The pregnane X receptor (PXR) is a master regulator of genes involved in drug elimination. Recently, activation of PXR has also been linked to the development of many disease conditions such as metabolic disorders and malignancies. MicroRNAs (miRs) emerge as important molecular species involved in these conditions. This study was undertaken to test a large number of miRs for their ability to regulate PXR expression. As many as 58 miRs were tested and miR-30c-1-3p was identified to suppress PXR expression. The suppression was achieved by targeting the 3'-untranslated region, 438 nucleotides from the stop codon. The suppression was detected in multiple cell lines from different organ origins. In addition, miR-30c-1-3p altered basal and induced expression of cytochrome P450 3A4 (CYP3A4), a prototypical target gene of PXR. The alteration varied depending on the time and amounts of miR-30c-1-3p. CYP3A4 is responsible for the metabolism of more than 50% medicines. The interconnection between miR-30c-1-3p and PXR signifies a role of miRs in drug-drug interactions and chemosensitivity. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie. PMID:27085140

  13. Effects of Ontogeny on δ13C of Plant- and Soil-Respired CO2 and on Respiratory Carbon Fractionation in C3 Herbaceous Species.

    Directory of Open Access Journals (Sweden)

    Yann Salmon

    Full Text Available Knowledge gaps regarding potential ontogeny and plant species identity effects on carbon isotope fractionation might lead to misinterpretations of carbon isotope composition (δ13C of respired CO2, a widely-used integrator of environmental conditions. In monospecific mesocosms grown under controlled conditions, the δ13C of C pools and fluxes and leaf ecophysiological parameters of seven herbaceous species belonging to three functional groups (crops, forage grasses and legumes were investigated at three ontogenetic stages of their vegetative cycle (young foliage, maximum growth rate, early senescence. Ontogeny-related changes in δ13C of leaf- and soil-respired CO2 and 13C/12C fractionation in respiration (ΔR were species-dependent and up to 7‰, a magnitude similar to that commonly measured in response to environmental factors. At plant and soil levels, changes in δ13C of respired CO2 and ΔR with ontogeny were related to changes in plant physiological status, likely through ontogeny-driven changes in the C sink to source strength ratio in the aboveground plant compartment. Our data further showed that lower ΔR values (i.e. respired CO2 relatively less depleted in 13C were observed with decreasing net assimilation. Our findings highlight the importance of accounting for ontogenetic stage and plant community composition in ecological studies using stable carbon isotopes.

  14. Biology and air-sea gas exchange controls on the distribution of carbon isotope ratios (δ13C) in the ocean

    Science.gov (United States)

    Schmittner, A.; Gruber, N.; Mix, A. C.; Key, R. M.; Tagliabue, A.; Westberry, T. K.

    2013-09-01

    Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate processes that control the distribution of δ13C of dissolved inorganic carbon (DIC) in the contemporary and preindustrial ocean. Biological fractionation and the sinking of isotopically light δ13C organic matter from the surface into the interior ocean leads to low δ13CDIC values at depths and in high latitude surface waters and high values in the upper ocean at low latitudes with maxima in the subtropics. Air-sea gas exchange has two effects. First, it acts to reduce the spatial gradients created by biology. Second, the associated temperature-dependent fractionation tends to increase (decrease) δ13CDIC values of colder (warmer) water, which generates gradients that oppose those arising from biology. Our model results suggest that both effects are similarly important in influencing surface and interior δ13CDIC distributions. However, since air-sea gas exchange is slow in the modern ocean, the biological effect dominates spatial δ13CDIC gradients both in the interior and at the surface, in contrast to conclusions from some previous studies. Calcium carbonate cycling, pH dependency of fractionation during air-sea gas exchange, and kinetic fractionation have minor effects on δ13CDIC. Accumulation of isotopically light carbon from anthropogenic fossil fuel burning has decreased the spatial variability of surface and deep δ13CDIC since the industrial revolution in our model simulations. Analysis of a new synthesis of δ13CDIC measurements from years 1990 to 2005 is used to quantify preformed and remineralized contributions as well as the effects of biology and air-sea gas exchange. The model reproduces major features of the observed large-scale distribution of δ13CDIC as well as the individual contributions and effects. Residual misfits are documented and analyzed. Simulated surface and subsurface δ13CDIC are influenced by

  15. Biology and air–sea gas exchange controls on the distribution of carbon isotope ratios (δ13C in the ocean

    Directory of Open Access Journals (Sweden)

    A. Schmittner

    2013-09-01

    Full Text Available Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate processes that control the distribution of δ13C of dissolved inorganic carbon (DIC in the contemporary and preindustrial ocean. Biological fractionation and the sinking of isotopically light δ13C organic matter from the surface into the interior ocean leads to low δ13CDIC values at depths and in high latitude surface waters and high values in the upper ocean at low latitudes with maxima in the subtropics. Air–sea gas exchange has two effects. First, it acts to reduce the spatial gradients created by biology. Second, the associated temperature-dependent fractionation tends to increase (decrease δ13CDIC values of colder (warmer water, which generates gradients that oppose those arising from biology. Our model results suggest that both effects are similarly important in influencing surface and interior δ13CDIC distributions. However, since air–sea gas exchange is slow in the modern ocean, the biological effect dominates spatial δ13CDIC gradients both in the interior and at the surface, in contrast to conclusions from some previous studies. Calcium carbonate cycling, pH dependency of fractionation during air–sea gas exchange, and kinetic fractionation have minor effects on δ13CDIC. Accumulation of isotopically light carbon from anthropogenic fossil fuel burning has decreased the spatial variability of surface and deep δ13CDIC since the industrial revolution in our model simulations. Analysis of a new synthesis of δ13CDIC measurements from years 1990 to 2005 is used to quantify preformed and remineralized contributions as well as the effects of biology and air–sea gas exchange. The model reproduces major features of the observed large-scale distribution of δ13CDIC as well as the individual contributions and effects. Residual misfits are documented and analyzed. Simulated surface and subsurface

  16. 13C-urea and15N2-urea : Elegant markers to define location and kinetics of in vivo release from a colon-targeted delivery device in men

    NARCIS (Netherlands)

    Schellekens, R.C.A.; Olsder, G.; Maurer, M.; Kosterink, J.; Woerdenbach, H.J.; Wutzke, K.D.; Frijlink, H.W.; Stellaard, F.

    2010-01-01

    Background:13C-urea may be a suitable marker to assess the in vivo fate of colon-targeted dosage forms given by mouth. Release in the colon would lead to fermentation of13C-urea into13CO2and excretion of13CO2in breath, release in the small intestine to detection of13C-urea in blood and urine. The di

  17. A spectral line survey in the 2 mm and 1.3 mm windows toward the carbon rich envelope of IRC +10216

    OpenAIRE

    He, J. H.; Dinh-V-Trung; Kwok, S.; Mueller, H. S. P.; Zhang, Y.; T. Hasegawa; Peng, T. C.; Huang, Y C

    2008-01-01

    We present the results of our spectral line surveys in the 2 mm and 1.3 mm windows toward the carbon rich envelope of IRC +10216. Totally 377 lines are detected, among which 360 lines are assigned to 57 known molecules (including 29 rare isotopomers and 2 cyclic isomers). Only 17 weak lines remain unidentified. Rotational lines of isotopomers 13CCH and HN13C are detected for the first time in IRC +10216. The detection of the formaldehyde lines in this star is also confirmed. Possible abundanc...

  18. Estimating groundwater mixing and origin in an overexploited aquifer in Guanajuato, Mexico, using stable isotopes (strontium-87, carbon-13, deuterium and oxygen-18).

    Science.gov (United States)

    Horst, Axel; Mahlknecht, Jürgen; Merkel, Broder J

    2007-12-01

    Stable Isotopes (strontium-87, deuterium and oxygen-18, carbon-13) have been used to reveal different sources of groundwater and mixing processes in the aquifer of the Silao-Romita Valley in the state of Guanajuato, Mexico. Calcite dissolution appeared to be the main process of strontium release leading to relatively equal (87)Sr/(86)Sr ratios of 0.7042-0.7062 throughout the study area which could be confirmed by samples of carbonate rocks having similar Sr ratios (0.7041-0.7073). delta(13)C values (-11.91- -6.87 per thousand VPDB) of groundwaters confirmed the solution of carbonates but indicated furthermore influences of soil-CO(2). Deuterium and (18)O contents showed a relatively narrow range of-80.1- -70.0 per thousand VSMOW and -10.2- -8.8 per thousand, VSMOW, respectively but are affected by evaporation and mixing processes. The use of delta(13)C together with (87)Sr/(86)Sr revealed three possible sources: (i) carbonate-controlled waters showing generally higher Sr-concentrations, (ii) fissure waters with low-strontium contents and (iii) infiltrating water which is characterized by low delta(13)C and (87)Sr/(86)Sr ratios. The third component is affected by evaporation processes taking place before and during infiltration which might be increased by extraction and reinfiltration (irrigation return flow). PMID:18041622

  19. Spatial variability of carbon13C) and nitrogen (δ15N) stable isotope ratios in an Arctic marine food web

    DEFF Research Database (Denmark)

    Hansen, Joan Holst; Hedeholm, Rasmus Berg; Sünksen, Kaj;

    2012-01-01

    Stable isotopes of carbon13C) and nitrogen (δ15N) were used to examine trophic structures in an arctic marine food web at small and large spatial scales. Twelve species, from primary consumers to Greenland shark, were sampled at a large spatial scale near the west and east coasts of Greenland...

  20. Creep-resistant porous structures based on stereo-complex forming triblock copolymers of 1,3-trimethylene carbonate and lactides

    NARCIS (Netherlands)

    Zhang, Zheng; Grijpma, Dirk W.; Feijen, Jan

    2004-01-01

    Stereo-complexes (poly(ST–TMC–ST)) of enantiomeric triblock copolymers based on 1,3-trimethylene carbonate (TMC) and L- or D-lactide (poly(LLA–TMC–LLA) and poly(DLA–TMC–DLA)) were prepared. Films of poly(ST–TMC–ST) could be prepared by solvent casting mixtures of equal amounts of poly(LLA–TMC–LLA) a

  1. Microbial characterization of basalt formation waters targeted for geological carbon sequestration.

    Science.gov (United States)

    Lavalleur, Heather J; Colwell, Frederick S

    2013-07-01

    Geological carbon sequestration in basalts is a promising solution to mitigate carbon emissions into the Earth's atmosphere. The Wallula pilot well in Eastern Washington State, USA provides an opportunity to investigate how native microbial communities in basalts are affected by the injection of supercritical carbon dioxide into deep, alkaline formation waters of the Columbia River Basalt Group. Our objective was to characterize the microbial communities at five depth intervals in the Wallula pilot well prior to CO2 injection to establish a baseline community for comparison after the CO2 is injected. Microbial communities were examined using quantitative polymerase chain reaction to enumerate bacterial cells and 454 pyrosequencing to compare and contrast the diversity of the native microbial communities. The deepest depth sampled contained the greatest amount of bacterial biomass, as well as the highest bacterial diversity. The shallowest depth sampled harbored the greatest archaeal diversity. Pyrosequencing revealed the well to be dominated by the Proteobacteria, Firmicutes, and Actinobacteria, with microorganisms related to hydrogen oxidizers (Hydrogenophaga), methylotrophs (Methylotenera), methanotrophs (Methylomonas), iron reducers (Geoalkalibacter), sulfur oxidizers (Thiovirga), and methanogens (Methermicocccus). Thus, the Wallula pilot well is composed of a unique microbial community in which hydrogen and single-carbon compounds may play a significant role in sustaining the deep biosphere.

  2. Sulfonamide inhibition studies of the β-carbonic anhydrase from the newly discovered bacterium Enterobacter sp. B13.

    Science.gov (United States)

    Eminoğlu, Ayşenur; Vullo, Daniela; Aşık, Aycan; Çolak, Dilşat Nigar; Çanakçı, Sabriye; Beldüz, Ali Osman; Supuran, Claudiu T

    2016-04-01

    The genome of the newly identified bacterium Enterobacter sp. B13 encodes for a β-class carbonic anhydrases (CAs, EC 4.2.1.1), EspCA. This enzyme was recently cloned, and characterized kinetically by this group (J. Enzyme Inhib. Med. Chem. 2016, 31). Here we report an inhibition study with sulfonamides and sulfamates of this enzyme. The best EspCA inhibitors were some sulfanylated sulfonamides with elongated molecules, metanilamide, 4-aminoalkyl-benzenesulfonamides, acetazolamide, and deacetylated methazolamide (KIs in the range of 58.7-96.5nM). Clinically used agents such as methazolamide, ethoxzolamide, dorzolamide, brinzolamide, benzolamide, zonisamide, sulthiame, sulpiride, topiramate and valdecoxib were slightly less effective inhibitors (KIs in the range of 103-138nM). Saccharin, celecoxib, dichlorophenamide and many simple benzenesulfonamides were even less effective as EspCA inhibitors, with KIs in the range of 384-938nM. Identification of effective inhibitors of this bacterial enzyme may lead to pharmacological tools useful for understanding the physiological role(s) of the β-class CAs in bacterial pathogenicity/virulence. PMID:26920803

  3. Octa-ammonium POSS-conjugated single-walled carbon nanotubes as vehicles for targeted delivery of paclitaxel

    Directory of Open Access Journals (Sweden)

    Naghmeh Naderi

    2015-09-01

    Full Text Available Background: Carbon nanotubes (CNTs have unique physical and chemical properties. Furthermore, novel properties can be developed by attachment or encapsulation of functional groups. These unique properties facilitate the use of CNTs in drug delivery. We developed a new nanomedicine consisting of a nanocarrier, cell-targeting molecule, and chemotherapeutic drug and assessed its efficacy in vitro. Methods: The efficacy of a single-walled carbon nanotubes (SWCNTs-based nanoconjugate system is assessed in the targeted delivery of paclitaxel (PTX to cancer cells. SWCNTs were oxidized and reacted with octa-ammonium polyhedral oligomeric silsesquioxanes (octa-ammonium POSS to render them biocompatible and water dispersable. The functionalized SWCNTs were loaded with PTX, a chemotherapeutic agent toxic to cancer cells, and Tn218 antibodies for cancer cell targeting. The nanohybrid composites were characterized with transmission electron microscopy (TEM, Fourier transform infrared (FTIR, and ultraviolet–visible–near-infrared (UV–Vis–NIR. Additionally, their cytotoxic effects on Colon cancer cell (HT-29 and Breast cancer cell (MCF-7 lines were assessed in vitro. Results: TEM, FTIR, and UV–Vis–NIR studies confirmed side-wall functionalization of SWCNT with COOH-groups, PTX, POSS, and antibodies. Increased cell death was observed with PTX–POSS–SWCNT, PTX–POSS–Ab–SWCNT, and free PTX compared to functionalized-SWCNT (f-SWCNT, POSS–SWCNT, and cell-only controls at 48 and 72 h time intervals in both cell lines. At all time intervals, there was no significant cell death in the POSS–SWCNT samples compared to cell-only controls. Conclusion: The PTX-based nanocomposites were shown to be as cytotoxic as free PTX. This important finding indicates successful release of PTX from the nanocomposites and further reiterates the potential of SWCNTs to deliver drugs directly to targeted cells and tissues.

  4. Recurrent Amplification at 13q34 Targets at CUL4A, IRS2, and TFDP1 As an Independent Adverse Prognosticator in Intrahepatic Cholangiocarcinoma.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Liu

    Full Text Available Amplification of genes at 13q34 has been reported to be associated with tumor proliferation and progression in diverse types of cancers. However, its role in intrahepatic cholangiocarcinoma (iCCA has yet to be explored. We examined two iCCA cell lines and 86 cases of intrahepatic cholangiocarcinoma to analyze copy number of three target genes, including cullin 4A (CUL4A, insulin receptor substrate 2 (IRS2, and transcription factor Dp-1 (TFDP1 at 13q34 by quantitative real-time polymerase chain reaction. The cell lines and all tumor samples were used to test the relationship between copy number (CN alterations and protein expression by western blotting and immunohistochemical assays, respectively. IRS2 was introduced, and each target gene was silenced in cell lines. The mobility potential of cells was compared in the basal condition and after manipulation using cell migration and invasion assays. CN alterations correlated with protein expression levels. The SNU1079 cell line containing deletions of the target genes demonstrated decreased protein expression levels and significantly lower numbers of migratory and invasive cells, as opposed to the RBE cell line, which does not contain CN alterations. Overexpression of IRS2 by introducing IRS2 in SUN1079 cells increased the mobility potential. In contrast, silencing each target gene showed a trend or statistical significance toward inhibition of migratory and invasive capacities in RBE cells. In tumor samples, the amplification of each of these genes was associated with poor disease-free survival. Twelve cases (13.9% demonstrated copy numbers > 4 for all three genes tested (CUL4A, IRS2, and TFDP1, and showed a significant difference in disease-free survival by both univariate and multivariate survival analyses (hazard ratio, 2.69; 95% confidence interval, 1.23 to 5.88; P = 0.013. Our data demonstrate that amplification of genes at 13q34 plays an oncogenic role in iCCA featuring adverse disease

  5. Targeted anti-cancer prodrug based on carbon nanotube with photodynamic therapeutic effect and pH-triggered drug release

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Jianquan; Zeng, Fang, E-mail: mcfzeng@scut.edu.cn; Xu, Jiangsheng; Wu, Shuizhu, E-mail: shzhwu@scut.edu.cn [South China University of Technology, College of Materials Science and Engineering, State Key Laboratory of Luminescent Materials and Devices (China)

    2013-09-15

    Herein, we describe a multifunctional anti-cancer prodrug system based on water-dispersible carbon nanotube (CNT); this prodrug system features active targeting, pH-triggered drug release, and photodynamic therapeutic properties. For this prodrug system (with the size of {approx}100-300 nm), an anti-cancer drug, doxorubicin (DOX), was incorporated onto CNT via a cleavable hydrazone bond; and a targeting ligand (folic acid) was also coupled onto CNT. This prodrug can preferably enter folate receptor (FR)-positive cancer cells and undergo intracellular release of the drug triggered by the reduced pH. The targeted CNT-based prodrug system can cause lower cell viability toward FR-positive cells compared to the non-targeted ones. Moreover, the CNT carrier exhibits photodynamic therapeutic (PDT) action; and the cell viability of FR-positive cancer cells can be further reduced upon light irradiation. The dual effects of pH-triggered drug release and PDT increase the therapeutic efficacy of the DOX-CNT prodrug. This study may offer some useful insights on designing and improving the applicability of CNT for other drug delivery systems.

  6. Biosynthetic control of the natural abundance of carbon 13 at specific positions within fatty acids in Escherichia coli. Evidence regarding the coupling of fatty acid and phospholipid synthesis

    International Nuclear Information System (INIS)

    Stable carbon isotope ratios (13C/12C) at natural abundance levels have been determined for individual carbon atoms in each of the major phospholipid fatty acids of Escherichia coli grown on glucose as the sole carbon source. Two models were constructed for the isotope effects and carbon flow pathways which must be responsible for the observed isotopic fractionations. Both models incorporate a branch in the carbon flow at which fatty acyl-acyl carrier protein (acyl-ACP) is utilized either for complex lipid synthesis or for elongation by fatty acid synthetase. Depletion of carbon 13 in the carboxyl groups of myristic and palmitoleic acids (relative to carbonyl groups in precursor acyl-ACP's) was observed to occur at this branching site. Only one of the models was consistent both with this observation and with the observation that exogenous fatty acids are incorporated into phospholipids but are not elongated. The successful model has free fatty acid as the intermediate product coupling fatty acid biosynthesis to phospholipid synthesis. Essential to this pathway are those reactions catalyzed by thioesterases I and II as well as acyl-ACP synthetase, enzymes whose roles have previously been unknown in vivo

  7. Assessing offsets between the δ13C of sedimentary components and the global exogenic carbon pool across early Paleogene carbon cycle perturbations

    NARCIS (Netherlands)

    Sluijs, A.; Dickens, G.R.

    2012-01-01

    Negative stable carbon isotope excursions (CIEs) across the Paleocene–Eocene thermal maximum (PETM; ∼56 Ma) range between 2‰ and 7‰, even after discounting sections with truncated records. Individual carbon isotope records differ in shape and magnitude from variations in the global exogenic carbon c

  8. Mamizu climate policy: an evaluation of Japanese carbon emissions reduction targets

    International Nuclear Information System (INIS)

    This letter evaluates Japan's so-called 'Mamizu' climate policies proposed in mid-2009 in terms of the implied rates of decarbonization of the Japanese economy for short-term and long-term targets. The letter uses the Kaya identity to structure the evaluation, employing both a bottom up approach (based on projections of future Japanese population, economic growth, and technology) and a top down approach (deriving implied rates of decarbonization consistent with the targets and various rates of economic growth). Both approaches indicate that the Japanese economy would have to achieve rates of decarbonization of 2.6% to meet a 2020 target of reducing emissions by 15% below 2005 levels, and 5.0% to meet a 2050 target of an 80% reduction below 2005 levels. A target of 25% below 1990 emissions proposed by the opposition party (which subsequently formed a government following elections in August 2009) implies a rate of decarbonization of 4.6% annually to 2020. The letter argues that international criticism of Japanese Mamizu climate policy proposals as being too weak was unfounded, and if anything, the proposals may have been too ambitious. In either case, climate policy would be strengthened through the support of a diversity of approaches to decarbonization.

  9. Chemical investigations of isotope separation on line target units for carbon and nitrogen beams

    CERN Document Server

    Franberg, H; Gäggeler, H W; Köster, U

    2006-01-01

    Radioactive ion beams (RIBs) are of significant interest in a number of applications. Isotope separation on line (ISOL) facilities provide RIB with high beam intensities and good beam quality. An atom that is produced within the ISOL target will first diffuse out from the target material. During the effusion towards the transfer line and into the ion source the many contacts with the surrounding surfaces may cause unacceptable delays in the transport and, hence, losses of the shorter-lived isotopes. We performed systematic chemical investigations of adsorption in a temperature and concentration regime relevant for ISOL targets and ion source units, with regard to CO/sub x/ and NOmaterials are potential construction materials for the above-mentioned areas. Off-line and on-line tests have been performed using a gas thermochromatography setup with radioactive tracers. The experiments were performed at the production of tracers for atmospheric chemistry (PROTRAC) facility at the Paul Schener Institute in Villigen...

  10. Direct growth and patterning of multilayer graphene onto a targeted substrate without an external carbon source.

    Science.gov (United States)

    Kang, Dongseok; Kim, Won-Jun; Lim, Jung Ah; Song, Yong-Won

    2012-07-25

    Using only a simple tube furnace, we demonstrate the synthesis of patterned graphene directly on a designed substrate without the need for an external carbon source. Carbon atoms are absorbed onto Ni evaporator sources as impurities, and incorporated into catalyst layers during the deposition. Heat treatment conditions were optimized so that the atoms diffused out along the grain boundaries to form nanocrystals at the catalyst-substrate interfaces. Graphene patterns were obtained under patterned catalysts, which restricted graphene formation to within patterned areas. The resultant multilayer graphene was characterized by Raman spectroscopy and transmission electron microscopy to verify the high crystallinity and two-dimensional nanomorphology. Finally, a metal-semiconductor diode with a catalyst-graphene contact structure were fabricated and characterized to assess the semiconducting properties of the graphene sheets with respect to the display of asymmetric current-voltage behavior. PMID:22709270

  11. Direct growth and patterning of multilayer graphene onto a targeted substrate without an external carbon source.

    Science.gov (United States)

    Kang, Dongseok; Kim, Won-Jun; Lim, Jung Ah; Song, Yong-Won

    2012-07-25

    Using only a simple tube furnace, we demonstrate the synthesis of patterned graphene directly on a designed substrate without the need for an external carbon source. Carbon atoms are absorbed onto Ni evaporator sources as impurities, and incorporated into catalyst layers during the deposition. Heat treatment conditions were optimized so that the atoms diffused out along the grain boundaries to form nanocrystals at the catalyst-substrate interfaces. Graphene patterns were obtained under patterned catalysts, which restricted graphene formation to within patterned areas. The resultant multilayer graphene was characterized by Raman spectroscopy and transmission electron microscopy to verify the high crystallinity and two-dimensional nanomorphology. Finally, a metal-semiconductor diode with a catalyst-graphene contact structure were fabricated and characterized to assess the semiconducting properties of the graphene sheets with respect to the display of asymmetric current-voltage behavior.

  12. Assessing the environmental potential of carbon dioxide utilization: A graphical targeting approach

    OpenAIRE

    Dumont, Marie-Noëlle

    2012-01-01

    Carbon Capture and Utilization (CCU) has the potential to reduce both greenhouse gas emissions and fossil fuel use. However, the conversion of CO2 is intrinsically difficult due to its low energetic state. Thus, a positive environmental effect of a CO2-consuming reaction cannot be taken for granted. In this work, we therefore present a graphical method to identify promising reaction schemes using CO2 as a feedstock. Reactant mixtures leading to minimal life-cycle greenhouse gas (GHG) emission...

  13. Targeting energy generation and carbon footprint for waste management and processing

    OpenAIRE

    Kravanja, Zdravko; Klemeš, Jiri; Čuček, Lidija; Varbanov, Petar

    2015-01-01

    Waste to Energy (WTE) processing carries a trade-off between energy extractionfrom the waste and the energy for waste management - collection, transport and treatment. Major performance indicators are the Primary Energy Savings (PES), Carbon Footprint (CFP) and especially the cost. This presentation analyses the significance of the factors in this trade-off introducing a new indicator - the Waste Energy Potential Utilisation (WPU). The results indicate that the impact of the logistics and ene...

  14. Interaction of carbon monoxide with transition metals: evolutionary insights into drug target discovery.

    Science.gov (United States)

    Foresti, Roberta; Motterlini, Roberto

    2010-12-01

    The perception that carbon monoxide (CO) is poisonous and life-threatening for mammalian organisms stems from its intrinsic propensity to bind iron in hemoglobin, a reaction that ultimately leads to impaired oxygen delivery to tissues. From evolutionary and chemical perspectives, however, CO is one of the most essential molecules in the formation of biological components and its interaction with transition metals is at the origin of primordial cell signaling. Not surprisingly, mammals have gradually evolved systems to finely control the synthesis and the sensing of this gaseous molecule. Cells are indeed continuously exposed to small quantities of CO produced endogenously during the degradation of heme by constitutive and inducible heme oxygenase enzymes. We have gradually learnt that heme oxygenase-derived carbon monoxide (CO) serves as a ubiquitous signaling mediator which could be exploited for therapeutic purposes. The development of transition metal carbonyls as prototypic carbon monoxide-releasing molecules (CO-RMs) represents a novel stratagem for a safer delivery of CO-based pharmaceuticals in the treatment of various pathological disorders. This review will look back at evolution to analyze and argue that a dynamic interaction of CO with specific intracellular metal centers is the common denominator for the diversified beneficial effects mediated by this gaseous molecule. PMID:20704543

  15. Reaction dynamics of {sup 34-38}Mg projectile with carbon target using Glauber model

    Energy Technology Data Exchange (ETDEWEB)

    Shama, Mahesh K., E-mail: maheshphy82@gmail.com [School of Physics and Material Sciences, Thapar University Patiala-147004 (India); Department of Applied Sciences, Chandigarh Engineering College, Landran Mohali-140307 (India); Panda, R. N. [Department of Physics, ITER, Shiksha O Anusandhan University, Bhubaneswar-751030 (India); Sharma, Manoj K. [School of Physics and Material Sciences, Thapar University Patiala-147004 (India); Patra, S. K. [Institute of Physics, Sachivalaya marg Bhubneswar-751005 (India)

    2015-08-28

    We have studied nuclear reaction cross-sections for {sup 34-38}Mg isotopes as projectile with {sup 12}C target at projectile energy 240AMeV using Glauber model with the conjunction of densities from relativistic mean filed formalism. We found good agreement with the available experimental data. The halo status of {sup 37}Mg is also investigated.

  16. The Precise Radio Observation of the 13C Isotopic Fractionation for Carbon Chain Molecule HC3N in the Low-Mass Star Forming Region L1527

    Science.gov (United States)

    Araki, Mitsunori; Takano, Shuro; Sakai, Nami; Yamamoto, Satoshi; Oyama, Takahiro; Kuze, Nobuhiko; Tsukiyama, Koichi

    2016-06-01

    We observed the three 13C isotopic species of HC3N with the high signal-to-noise ratios in L1527 using Green Bank 100 m telescope and Nobeyama 45 m telescope to explore the production scheme of HC3N, where L1527 is the low-mass star forming region in the phase of a warm carbon chain chemistry region. The spectral lines of the J = 5--4, 9--8, 10--9, and 12--11 transitions in the 44-109 GHz region were used to measure isotopic ratios. The abundance of HCCCN was determined from the line intensities of the two weak hyperfine components of the J = 5-4 transition. The isotopic ratios were precisely determined to be 1.00 : 1.01 : 1.35 : 86.4 for [H13CCCN] : [HC13CCN] : [HCC13CN] : [HCCCN]. It was found that the abundance of H13CCCN is equal to that of HC13CCN, and it was implied that HC3N is mainly formed by the reaction schemes via C2H2 and C2H2+ in L1527. This would suggest a universality of dicarbide chemistry producing HC3N irrespective of evolutional phases from a starless dark cloud to a warm carbon chain chemistry region. Sakai, N., Sakai, T., Hirota, T., & Yamamoto, S. 2008, ApJ, 672, 371 Takano, S., Masuda, A., Hirahara, Y., et al. 1998, A&A, 329, 1156

  17. Fate of organic carbon in paddy soils - results of Alisol and Andosol incubation with 13C marker

    Science.gov (United States)

    Winkler, Pauline; Cerli, Chiara; Fiedler, Sabine; Woche, Susanne; Rahayu Utami, Sri; Jahn, Reinhold; Kalbitz, Karsten; Kaiser, Klaus

    2016-04-01

    For a better understanding of organic carbon (OC) decomposition in paddy soils an incubation experiment was performed. Two soil types with contrasting mineralogy (Alisol and Andosol) were exposed to 8 anoxic‒oxic cycles over 1 year. Soils received rice straw marked with 13C (228 ‰) at the beginning of each cycle. A second set of samples without straw addition was used as control. Headspaces of the incubation vessels were regularly analysed for CO2 and CH4. In soil solutions, redox potential, pH, dissolved organic C (DOC), and Fe2+ were measured after each anoxic and each oxic phase. Soils were fractionated by density at the end of the experiment and the different fractions were isotopically analysed. Samples of genuine paddy soils that developed from the test soils were used as reference. During anoxic cycles, soils receiving rice straw released large amounts of CO2 and CH4, indicating strong microbial activity. Consequently, Eh values dropped and pH as well as Fe2+ concentrations increased. Concentrations of DOC were relatively small, indicating either strong consumption and/or strong retention of dissolved organic compounds. During oxic cycles, concentrations of dissolved Fe dropped in both soils while DOC concentrations remained constant in the Alisol and decreased in the Andosol. Density fractionation revealed increased contents of mineral associated OC for the Andosol incubated with straw addition as compared to the parent soil. No changes were found for the Alisol. However, the mineral-associated OC fraction of both soil types contained 13C of the added straw. Hence, fresh organic matter is incorporated while part of the older organic matter has been released or mineralized. The increase in the Andosol might be due to effective binding of fresh OC to minerals and/or stronger retention/preservation of older OC. Both could be explained by the more reactive mineralogy of the Andosol than of the Alisol. XPS analyses of the soils are currently performed and

  18. Chemical weathering and the role of sulfuric and nitric acids in carbonate weathering: Isotopes (13C, 15N, 34S, and 18O) and chemical constraints

    Science.gov (United States)

    Li, Cai; Ji, Hongbing

    2016-05-01

    Multiple isotopes (13C-DIC, 34S and 18O-SO42-, 15N and 18O-NO3-) and water chemistry were used to evaluate weathering rates and associated CO2 consumption by carbonic acid and strong acids (H2SO4 and HNO3) in a typical karst watershed (Wujiang River, Southwest China). The dual sulfate isotopes indicate that sulfate is mainly derived from sulfide oxidation in coal stratum and sulfide-containing minerals, and dual nitrate isotopes indicate that nitrate is mainly derived from soil N and nitrification. The correlation between isotopic compositions and water chemistry suggests that sulfuric and nitric acids, in addition to carbonic acid, are involved in carbonate weathering. The silicate and carbonate weathering rates are 7.2 t km-2 yr-1 and 76 t km-2 yr-1, respectively. In comparison with carbonate weathering rates (43 t km-2 yr-1) by carbonic acid alone, the subsequent increase in rates indicates significant enhancement of weathering when combined with sulfuric and nitric acids. Therefore, the role of sulfuric and nitric acids in the rock weathering should be considered in the global carbon cycle.

  19. BECCS capability of dedicated bioenergy crops under a future land-use scenario targeting net negative carbon emissions

    Science.gov (United States)

    Kato, E.; Yamagata, Y.

    2014-12-01

    Bioenergy with Carbon Capture and Storage (BECCS) is a key component of mitigation strategies in future socio-economic scenarios that aim to keep mean global temperature rise below 2°C above pre-industrial, which would require net negative carbon emissions in the end of the 21st century. Because of the additional need for land, developing sustainable low-carbon scenarios requires careful consideration of the land-use implications of deploying large-scale BECCS. We evaluated the feasibility of the large-scale BECCS in RCP2.6, which is a scenario with net negative emissions aiming to keep the 2°C temperature target, with a top-down analysis of required yields and a bottom-up evaluation of BECCS potential using a process-based global crop model. Land-use change carbon emissions related to the land expansion were examined using a global terrestrial biogeochemical cycle model. Our analysis reveals that first-generation bioenergy crops would not meet the required BECCS of the RCP2.6 scenario even with a high fertilizer and irrigation application. Using second-generation bioenergy crops can marginally fulfill the required BECCS only if a technology of full post-process combustion CO2 capture is deployed with a high fertilizer application in the crop production. If such an assumed technological improvement does not occur in the future, more than doubling the area for bioenergy production for BECCS around 2050 assumed in RCP2.6 would be required, however, such scenarios implicitly induce large-scale land-use changes that would cancel half of the assumed CO2 sequestration by BECCS. Otherwise a conflict of land-use with food production is inevitable.

  20. Bio-Carbon Accounting for Bio-Oil Co-Processing: 14C and 13C/12C

    Energy Technology Data Exchange (ETDEWEB)

    Mora, Claudia I. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Li, Zhenghua [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vance, Zachary [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-21

    This is a powerpoint presentation on bio-carbon accounting for bio-oil co-processing. Because of the overlapping range in the stable C isotope compositions of fossil oils and biooils from C3-type feedstocks, it is widely thought that stable isotopes are not useful to track renewable carbon during co-production. In contrast, our study demonstrates the utility of stable isotopes to: • capture a record of renewable carbon allocation between FCC products of co-processing • record changes in carbon apportionments due to changes in reactor or feed temperature Stable isotope trends as a function of percent bio-oil in the feed are more pronounced when the δ13C of the bio-oil endmember differs greatly from the VGO (i.e., it has a C4 biomass source–corn stover, switch grass, Miscanthus, sugarcane– versus a C3 biomass source– pine, wheat, rice, potato), but trends on the latter case are significant for endmember differences of just a few permil. The correlation between measured 14C and δ13C may be useful as an alternative to carbon accounting, but the relationship must first be established for different bio-oil sources.

  1. The importance of cellular internalization of antibody-targeted carbon nanotubes in the photothermal ablation of breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Marches, Radu; Vitetta, Ellen S [Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas, TX 75390 (United States); Mikoryak, Carole; Draper, Rockford K [Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75080 (United States); Wang, Ru-Hung; Pantano, Paul, E-mail: ellen.vitetta@utsouthwestern.edu [Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2011-03-04

    Single-walled carbon nanotubes (CNTs) convert absorbed near infrared (NIR) light into heat. The use of CNTs in the NIR-mediated photothermal ablation of tumor cells is attractive because the penetration of NIR light through normal tissues is optimal and the side effects are minimal. Targeted thermal ablation with minimal collateral damage can be achieved by using CNTs attached to tumor-specific monoclonal antibodies (MAbs). However, the role that the cellular internalization of CNTs plays in the subsequent sensitivity of the target cells to NIR-mediated photothermal ablation remains undefined. To address this issue, we used CNTs covalently coupled to an anti-Her2 or a control MAb and tested their ability to bind, internalize, and photothermally ablate Her2{sup +} but not Her2{sup -} breast cancer cell lines. Using flow cytometry, immunofluorescence, and confocal Raman microscopy, we observed the gradual time-dependent receptor-mediated endocytosis of anti-Her2-CNTs whereas a control MAb-CNT conjugate did not bind to the cells. Most importantly, the Her2{sup +} cells that internalized the MAb-CNTs were more sensitive to NIR-mediated photothermal damage than cells that could bind to, but not internalize the MAb-CNTs. These results suggest that both the targeting and internalization of MAb-CNTs might result in the most effective thermal ablation of tumor cells following their exposure to NIR light.

  2. Chemical Investigations of ISOL target units for carbon and nitrogen beams

    CERN Document Server

    Franberg, H; Gäggeler, H W; Köster, U

    2006-01-01

    Radioactive Ion Beams (RIB) are of significant interest in a number of applications. ISOL (Isotope Separation On Line) facilities provide RIB with high beam intensities and good beam quality. An atom that is produced within the ISOL target will first diffuse out from the target material. During the effusion towards the transfer line and into the ion source the many contacts with the surrounding surfaces may cause unacceptable delays in the transport and, hence, losses of the shorter-lived isotopes. We performed systematic chemical investigations of adsorption in a temperature and concentration regime relevant for ISOL targets and ion source units, with regard to COx and NOx on Al2O3 and SiO2. These materials are potential construction materials for the above mentioned areas. Off-line and on-line tests have been performed using a gas thermo-chromatography set-up with radioactive tracers. The experiments were performed at the PROTRAC facility at Paul Scherrer Institute in Villigen, Switzerland.

  3. In Situ 13C NMR at Elevated-Pressures and -Temperatures Investigating the Conversion of CO2 to Magnesium and Calcium Carbonate Minerals

    Science.gov (United States)

    Surface, J. A.; Conradi, M. S.; Skemer, P. A.; Hayes, S. E.

    2013-12-01

    We have constructed specialized NMR hardware to conduct in situ elevated-pressure, elevated-temperature 13C NMR studies of unmixed heterogeneous mixtures of solids, liquids, gases, and supercritical fluids. Specifically, our aim is to monitor CO2 uptake in both ultramafic rocks and in more porous geological materials to understand the mechanisms of chemisorption as a function of temperature, pressure and pH. In this in situ NMR probe, we are able to simulate processes at geologically relevant fluid pressures and temperatures, monitoring the kinetics of CO2 conversion to carbonates. The in situ NMR experiments consist of heterogeneous mixtures of rock, salty brine solution, and moderate pressure CO2 gas at elevated temperatures. The purpose of studying these reactions is to determine efficacy of carbonate formation in various geological reservoirs. Via 13C NMR, we have spectroscopically characterized and quantified the conversion of CO2 to magnesium carbonate and calcium carbonate minerals. When CO2 reacts with the calcium or magnesium in a mineral or rock sample, the 13C chemical shift, linewidth, lineshape, and relaxation times change dramatically. This change can be monitored in situ and provide instantaneous and continuous characterization that maps the chemistry that is taking place. For example, on the pathway to MgCO3 formation, there are a number of phases of Mg(OH)x(H2O)y(CO3)z that are apparent via NMR spectroscopy. We will demonstrate that NMR can be used for quantitative characterization of multiple metastable mineral phases in pure forms and in mixtures. Results are confirmed via powder XRD and Raman spectroscopy of aquo- hydro- carbonato- magnesium species and calcium carbonate species. We also have monitored the 13C spectroscopy to analyze the phase of CO2 (liquid, supercritical, or gas) and its conversion into other forms, such as bicarbonate and carbonate species, providing a "window" into the in situ pH of the reacting system. Reference: 'In Situ

  4. Δ14C and δ13C as tracers of organic carbon in Baltic Sea sediments collected in coastal waters off Lithuania and in the Gotland Deep

    International Nuclear Information System (INIS)

    Signatures of Δ14C and δ13C of total organic carbon in sediments as well as of total lipid extracts and phospholipid-derived fatty acid fractions isolated from the surface (0-3 cm) sediments collected in the Curonian Lagoon and in the open Baltic Sea were studied. An endmember mixing-model approach was applied to estimate relative contributions of the marine and terrestrial inputs to organic carbon in sediments, and to elucidate a possible leakage of chemical warfare agents at the Gotland Deep dumpsite. (author)

  5. Proton And Carbon-13 Nuclear Magnetic Resonance Of Some 4-Amino-3-Alkyl (Aryl)-5-Thio-1,2,4-Triazolines And Their Derivatives

    OpenAIRE

    El Toukhy, Ahmed [احمد الطوخي; Al-Kubaisi, Abdulla H.; Kenawy, Ibrahim

    1991-01-01

    The proton and carbon-13 NMR spectra of some 4-amino-3-alkyl(aryl)-5-thio-1,2,4-triazolines, some 3-alkyl-5-thio- 1,2,4-triazolines and some 4-amino-3-aryl-5-thio-l,2,4-triazoles were measured in DMSO-d6 as solvent. The chemical shift for each proton and carbon in these compounds were assigned. The 'H, chemical shift of N-H protons of the thioamide group and the "C chemical shift of C(3) in the triazolines were found to be sensitive to the substituent R (alkyi or aryl) at C(3), and correlated...

  6. Report on compounds labelled with nitrogen-13 or carbon-11 used in cancer metabolic studies with quantitative two-dimensional scanning and pet tomography

    International Nuclear Information System (INIS)

    The use of compounds labelled with radionuclides of the elements commonly involved in metabolic processes (oxygen, carbon, nitrogen) is becoming important in the non-invasive study of organ and tumour function. The application of compounds labelled with 13N and 11C to the study of amino-acid metabolism and changes in vasculature following chemotherapy and radiation therapy is described. In particular, 13N-labelled L-glutamate has been found to be useful in visualizing a number of human tumours including osteogenic sarcoma, rhabdomyosarcoma, Ewing's sarcoma, malignant fibrous histiocytoma, pineal gland tumours, primitive neuroectodermal tumours, medulloblastoma and several other solid tumours. In patients with bone tumours, changes in 13N-L-glutamate scans during chemotherapy were found to correlate with changes in other clinical parameters, such as serum alkaline phosphatase, histology and 99Tcsup(m)-bone scans, thus indicating that labelled L-glutamate is potentially useful in evaluating the response of solid tumours to chemotherapy. Scans of patients and volunteers using 13N-L-glutamate and 13N-L-valine indicate that the L-amino acids may be useful in studies of metabolic processes in the liver, myocardium and pancreas. Red blood cells, labelled with 11C-carbon monoxide via inhalation of the radioactive gas, have been used to assess changes in tumour vascularity following radiation therapy. Alpha-aminoisobutyric acid labelled with 11C has been synthesized and its distribution in normal and tumour-bearing dogs has been studied. (author)

  7. Negative ion productions in high velocity collision between small carbon clusters and Helium atom target

    International Nuclear Information System (INIS)

    We measured absolute double capture cross section of Cn+ ions (n=1,5) colliding, at 2.3 and 2.6 a.u velocities, with an Helium target atom and the branching ratios of fragmentation of the so formed electronically excited anions Cn−*. We also measured absolute cross section for the electronic attachment on neutral Cn clusters colliding at same velocities with He atom. This is to our knowledge the first measurement of neutral-neutral charge exchange in high velocity collision.

  8. Carbonic anhydrase enzyme as a potential therapeutic target for experimental trichinellosis.

    Science.gov (United States)

    Saad, Abeer E; Ashour, Dalia S; Abou Rayia, Dina M; Bedeer, Asmaa E

    2016-06-01

    Trichinellosis is a globally distributed helminthic infection. There is a considerable interest in developing new anti-helminthic drugs affecting all the developmental stages of Trichinella. Acetazolamide (carbonic anhydrase (CA) inhibitor) involves a novel mechanism of action by inhibiting such an essential enzyme for parasite metabolism. This work aimed to study the effect of acetazolamide against different stages of T. spiralis in experimental animals. Mice were divided into three groups: group I: infected and treated with acetazolamide on day 2 post infection (P.I.), group II: infected and treated with acetazolamide on day 12 P.I., and group III: infected non-treated. From each group, small intestine and muscles were removed for histopathological and immunohistochemical studies. Also, total adult and muscle larval count were estimated. We found that acetazolamide was effective in reduction of both adult and muscle larval counts. When given early, the effect was more pronounced on the adults (62.7 %). However, the efficacy of the drug against muscle larvae was increased when given late (63 %). Improvement of the intestinal histopathological changes was observed in all the treated groups. Degeneration of encysted larvae with minimal pathologic changes of infected skeletal muscle was observed in the treated groups. Expression of matrix metalloproteinase-9 showed a statistically significant decrease in the intestinal and muscle tissues in all treated groups as compared to the control group. In conclusion, the present study revealed that acetazolamide, carbonic anhydrase inhibitor, could be a promising drug against both adults and larvae of T. spiralis. PMID:26979731

  9. Osilodrostat (LCI699), a potent 11β-hydroxylase inhibitor, administered in combination with the multireceptor-targeted somatostatin analog pasireotide: A 13-week study in rats

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li, E-mail: li1.li@novartis.com [Preclinical Safety, Novartis Institutes for BioMedical Research, East Hanover, NJ (United States); Vashisht, Kapil; Boisclair, Julie [Preclinical Safety, Novartis Institutes for BioMedical Research, East Hanover, NJ (United States); Li, Wenkui; Lin, Tsu-han [Drug Metabolism and Pharmacokinetics, Novartis Institutes for BioMedical Research, East Hanover, NJ (United States); Schmid, Herbert A. [Novartis Oncology Development, Basel (Switzerland); Kluwe, William; Schoenfeld, Heidi; Hoffmann, Peter [Preclinical Safety, Novartis Institutes for BioMedical Research, East Hanover, NJ (United States)

    2015-08-01

    The somatostatin analog pasireotide and the 11β-hydroxylase inhibitor osilodrostat (LCI699) reduce cortisol levels by distinct mechanisms of action. There exists a scientific rationale to investigate the clinical efficacy of these two agents in combination. This manuscript reports the results of a toxicology study in rats, evaluating different doses of osilodrostat and pasireotide alone and in combination. Sixty male and 60 female rats were randomized into single-sex groups to receive daily doses of pasireotide (0.3 mg/kg/day, subcutaneously), osilodrostat (20 mg/kg/day, orally), osilodrostat/pasireotide in combination (low dose, 1.5/0.03 mg/kg/day; mid-dose, 5/0.1 mg/kg/day; or high dose, 20/0.3 mg/kg/day), or vehicle for 13 weeks. Mean body-weight gains from baseline to Week 13 were significantly lower in the pasireotide-alone and combined-treatment groups compared to controls, and were significantly higher in female rats receiving osilodrostat monotherapy. Osilodrostat and pasireotide monotherapies were associated with significant changes in the histology and mean weights of the pituitary and adrenal glands, liver, and ovary/oviduct. Osilodrostat alone was associated with adrenocortical hypertrophy and hepatocellular hypertrophy. In combination, osilodrostat/pasireotide did not exacerbate any target organ changes and ameliorated the liver and adrenal gland changes observed with monotherapy. C{sub max} and AUC{sub 0–24h} of osilodrostat and pasireotide increased in an approximately dose-proportional manner. In conclusion, the pasireotide and osilodrostat combination did not exacerbate changes in target organ weight or toxicity compared with either monotherapy, and had an acceptable safety profile; addition of pasireotide to the osilodrostat regimen may attenuate potential adrenal gland hyperactivation and hepatocellular hypertrophy, which are potential side effects of osilodrostat monotherapy. - Highlights: • We examined the target organ toxicity of SOM230

  10. A graphitic hollow carbon nitride nanosphere as a novel photochemical internalization agent for targeted and stimuli-responsive cancer therapy

    Science.gov (United States)

    Liu, Chaoqun; Chen, Zhaowei; Wang, Zhenzhen; Li, Wei; Ju, Enguo; Yan, Zhengqing; Liu, Zhen; Ren, Jinsong; Qu, Xiaogang

    2016-06-01

    As a novel technique, photochemical internalization (PCI) has been employed as a new approach to overcome endo/lysosomal restriction, which is one of the main difficulties in both drug and gene delivery. However, the complicated synthesis procedure (usually requiring the self-assembly of polymers, photosensitizers and cargos) and payload specificity greatly limit its further application. In this paper, we employ a highly fluorescent graphitic hollow carbon nitride nanosphere (GHCNS) to simultaneously serve as a PCI photosensitizer, an imaging agent and a drug carrier. The surface modification of GHCNS with multifunctional polysaccharide hyaluronic acid (HA) endows the system with colloidal stability, biocompatibility and cancer cell targeting ability. After CD44 receptor-mediated endocytosis, the nanosystem is embedded in endo/lysosomal vesicles and HA could be specially degraded by hyaluronidase (Hyal), inducing open pores. In the following, with visible light illumination, GHCNS could produce ROS that effectively induced lipid peroxidation and caused endo/lysosomal membrane break, accelerating the cytoplasmic release of the drug in the targeted and irradiated cells. As a result, significantly increased therapeutic potency and specificity against cancer cells could be achieved.As a novel technique, photochemical internalization (PCI) has been employed as a new approach to overcome endo/lysosomal restriction, which is one of the main difficulties in both drug and gene delivery. However, the complicated synthesis procedure (usually requiring the self-assembly of polymers, photosensitizers and cargos) and payload specificity greatly limit its further application. In this paper, we employ a highly fluorescent graphitic hollow carbon nitride nanosphere (GHCNS) to simultaneously serve as a PCI photosensitizer, an imaging agent and a drug carrier. The surface modification of GHCNS with multifunctional polysaccharide hyaluronic acid (HA) endows the system with colloidal

  11. Energy and environmental implications of carbon emission reduction targets: Case of Kathmandu Valley, Nepal

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Ram M., E-mail: ram.m.shrestha@gmail.co [School of Environment, Resources and Development, Asian Institute of Technology (Thailand); Rajbhandari, Salony [School of Environment, Resources and Development, Asian Institute of Technology (Thailand)

    2010-09-15

    This paper analyzes the sectoral energy consumption pattern and emissions of CO{sub 2} and local air pollutants in the Kathmandu Valley, Nepal. It also discusses the evolution of energy service demands, structure of energy supply system and emissions from various sectors under the base case scenario during 2005-2050. A long term energy system planning model of the Kathmandu Valley based on the MARKet ALlocation (MARKAL) framework is used for the analyses. Furthermore, the paper analyzes the least cost options to achieve CO{sub 2} emission reduction targets of 10%, 20% and 30% below the cumulative emission level in the base case and also discusses their implications for total cost, technology-mix, energy-mix and local pollutant emissions. The paper shows that a major switch in energy use pattern from oil and gas to electricity would be needed in the Valley to achieve the cumulative CO{sub 2} emission reduction target of 30% (ER30). Further, the share of electricity in the cumulative energy consumption of the transport sector would increase from 12% in the base case to 24% in the ER30 case.

  12. Energy and environmental implications of carbon emission reduction targets. Case of Kathmandu Valley, Nepal

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Ram M.; Rajbhandari, Salony [School of Environment, Resources and Development, Asian Institute of Technology (Thailand)

    2010-09-15

    This paper analyzes the sectoral energy consumption pattern and emissions of CO{sub 2} and local air pollutants in the Kathmandu Valley, Nepal. It also discusses the evolution of energy service demands, structure of energy supply system and emissions from various sectors under the base case scenario during 2005-2050. A long term energy system planning model of the Kathmandu Valley based on the MARKet ALlocation (MARKAL) framework is used for the analyses. Furthermore, the paper analyzes the least cost options to achieve CO{sub 2} emission reduction targets of 10%, 20% and 30% below the cumulative emission level in the base case and also discusses their implications for total cost, technology-mix, energy-mix and local pollutant emissions. The paper shows that a major switch in energy use pattern from oil and gas to electricity would be needed in the Valley to achieve the cumulative CO{sub 2} emission reduction target of 30% (ER30). Further, the share of electricity in the cumulative energy consumption of the transport sector would increase from 12% in the base case to 24% in the ER30 case. (author)

  13. Energy and environmental implications of carbon emission reduction targets: Case of Kathmandu Valley, Nepal

    International Nuclear Information System (INIS)

    This paper analyzes the sectoral energy consumption pattern and emissions of CO2 and local air pollutants in the Kathmandu Valley, Nepal. It also discusses the evolution of energy service demands, structure of energy supply system and emissions from various sectors under the base case scenario during 2005-2050. A long term energy system planning model of the Kathmandu Valley based on the MARKet ALlocation (MARKAL) framework is used for the analyses. Furthermore, the paper analyzes the least cost options to achieve CO2 emission reduction targets of 10%, 20% and 30% below the cumulative emission level in the base case and also discusses their implications for total cost, technology-mix, energy-mix and local pollutant emissions. The paper shows that a major switch in energy use pattern from oil and gas to electricity would be needed in the Valley to achieve the cumulative CO2 emission reduction target of 30% (ER30). Further, the share of electricity in the cumulative energy consumption of the transport sector would increase from 12% in the base case to 24% in the ER30 case.

  14. Acetalization of carbonyl compounds with 2,2,4-trimethyl-1,3-pentanedio catalyzed by novel carbon based solid acid catalyst

    Institute of Scientific and Technical Information of China (English)

    Ling Liu; Yuechang Zhao; Shan Gan; Xuezheng Liang; Jianguo Yang; Mingyuan He

    2008-01-01

    The synthesis of 2, 4-diisopropyl-5,5-dimethyl-1,3-dioxane through the acetalization of isobutyraldehyde with 2, 2,4-trimethyl-1,3-pentanediol (TMPD) catalyzed by the novel carbon based acid was first carried out. High conversion (≥98%) and specific selectivity were obtained using the novel carbon based acid, which kept high activity after it was reused 5 times.Moreover, the catalyst could be used to catalyze the acetalization and ketalization of different aldehydes and ketones with superior yield. The yield of several products was over 90%. The novel heterogeneous catalyst has the distinct advantages of high activity, strikingly simple workup procedure, non-pollution, and reusability, which will contribute to the success of the green process greatly.

  15. Multi-functionalized hyaluronic acid nanogels crosslinked with carbon dots as dual receptor-mediated targeting tumor theranostics.

    Science.gov (United States)

    Jia, Xu; Han, Yu; Pei, Mingliang; Zhao, Xubo; Tian, Kun; Zhou, Tingting; Liu, Peng

    2016-11-01

    Hyaluronic acid (HA)-based theranostic nanogels were designed for the tumor diagnosis and chemotherapy, by crosslinking the folate-terminated poly(ethylene glycol) modified hyaluronic acid (FA-PEG-HA) with carbon dots (CDs) for the first time. Due to the extraordinary fluorescence property of the integrated CDs, the theranostic nanogels could be used for the real-time and noninvasive location tracking to cancer cells. HA could load Doxorubicin (DOX) via electrostatic interaction with a drug-loading capacity (DLC) of 32.5%. The nanogels possessed an ideal release of DOX in the weak acid environment, while it was restrained in the neutral media, demonstrating the pH-responsive controlled release behavior. The cytotoxicity and cellular uptake results clearly illustrated that most DOX was released and accumulated in the cell nuclei and killed the cancer cells efficaciously, due to their dual receptor-mediated targeting characteristics. PMID:27516286

  16. Invariant mass spectrum and α-n correlation function studied in the fragmentation of 6He on a carbon target

    International Nuclear Information System (INIS)

    Momentum distributions and invariant mass spectra from the breakup of 6He ions with an energy of 240 MeV/u interacting with a carbon target have been studied. The data were used to extract information about the reaction mechanism which is influenced by the structure of 6He. It is found that the dominant reaction mechanism is a two-step process: knock out of one neutron followed by the decay of the 5He resonance. The shape of the (α+n) two-body invariant mass spectrum is interpreted as mainly reflecting the 5He ground state which is a Jπ=3/2- resonance. However, no evidence for correlations between α particles and neutrons is observed in the momentum widths of the distributions. It is demonstrated that a combined analysis of the two-body invariant mass spectrum and an appropriate correlation function may be used to determine the properties of the intermediate resonance. (orig.)

  17. Application of δ13C and δ15N isotopic signatures of organic matter fractions sequentially separated from adjacent arable and forest soils to identify carbon stabilization mechanisms

    Directory of Open Access Journals (Sweden)

    M. Sommer

    2011-03-01

    Full Text Available Identifying the chemical mechanisms behind soil carbon bound in organo-mineral complexes is necessary to determine the degree to which soil organic carbon is stabilized belowground. We used the δ13C and δ15N isotopic signatures from two organic matter (OM fractions from soil to identify the likely binding mechanisms involved. We used OM fractions hypothesized to contain carbon stabilized through organo-mineral complexes: (1 OM separated chemically with sodium pyrophosphate (OM(PY and (2 OM stabilized in microstructures found in the chemical extraction residue (OM(ER. Furthermore, because the OM fractions were separated from five different soils with paired forest and arable land use histories, we could address the impact of land use change on carbon binding and processing mechanisms within these soils. We used partial least squares regression to analyze patterns in the isotopic signature of OM with established proxies of different binding mechanisms. Parsing soil OM into different fractions is a systematic method of dissection, however, we are primarily interested in how OM is bound in soil as a whole, requiring a means of re-assembly. Thus, we implemented the recent zonal framework described by Kleber et al. (2007 to relate our findings to undisturbed soil. The δ15N signature of OM fractions served as a reliable indicator for microbial processed carbon in both arable and forest land use types. The δ13C signature of OM fractions in arable sites did not correlate well with proxies of soil mineral properties while a consistent pattern of enrichment was seen in the δ13C of OM fractions in the forest sites. We found a significant difference in δ13C of pooled OM fractions between the forest and arable land use type although it was relatively small (<1‰. We found different binding mechanisms predominate in each land use type. The isotopic signatures of OM fractions from arable soils were highly related to the clay and silt size particles

  18. Application of δ13C and δ15N isotopic signatures of organic matter fractions sequentially separated from adjacent arable and forest soils to identify carbon stabilization mechanisms

    Science.gov (United States)

    Kayler, Z. E.; Kaiser, M.; Gessler, A.; Ellerbrock, R. H.; Sommer, M.

    2011-03-01

    Identifying the chemical mechanisms behind soil carbon bound in organo-mineral complexes is necessary to determine the degree to which soil organic carbon is stabilized belowground. We used the δ13C and δ15N isotopic signatures from two organic matter (OM) fractions from soil to identify the likely binding mechanisms involved. We used OM fractions hypothesized to contain carbon stabilized through organo-mineral complexes: (1) OM separated chemically with sodium pyrophosphate (OM(PY)) and (2) OM stabilized in microstructures found in the chemical extraction residue (OM(ER)). Furthermore, because the OM fractions were separated from five different soils with paired forest and arable land use histories, we could address the impact of land use change on carbon binding and processing mechanisms within these soils. We used partial least squares regression to analyze patterns in the isotopic signature of OM with established proxies of different binding mechanisms. Parsing soil OM into different fractions is a systematic method of dissection, however, we are primarily interested in how OM is bound in soil as a whole, requiring a means of re-assembly. Thus, we implemented the recent zonal framework described by Kleber et al. (2007) to relate our findings to undisturbed soil. The δ15N signature of OM fractions served as a reliable indicator for microbial processed carbon in both arable and forest land use types. The δ13C signature of OM fractions in arable sites did not correlate well with proxies of soil mineral properties while a consistent pattern of enrichment was seen in the δ13C of OM fractions in the forest sites. We found a significant difference in δ13C of pooled OM fractions between the forest and arable land use type although it was relatively small (<1‰). We found different binding mechanisms predominate in each land use type. The isotopic signatures of OM fractions from arable soils were highly related to the clay and silt size particles amount while

  19. Turnover of carbon in the 13C-urea breath test for the detection of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    To obtain a standard protocol for the application of 13C-urea breath test (13C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of 13C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the 13C in the 13C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio 13C/12C in expired CO2 from patients infected with H. pylori and subjected to 13C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  20. Synthesizing the Use of Carbon Isotope (14C and 13C) Approaches to Understand Rates and Pathways for Permafrost C Mobilization and Mineralization

    Science.gov (United States)

    Estop-Aragones, C.; Olefeldt, D.; Schuur, E.

    2015-12-01

    To better understand the permafrost carbon (C) feedback it is important to synthesize our current knowledge, and knowledge gaps, of how permafrost thaw can cause in situ mineralization or downstream mobilization of aged soil organic carbon (SOC) and the rate of this release. This potential loss of old SOC may occur via gaseous flux of CO2 and CH4 exchanged between soil and the atmosphere and via waterborne flux as DOC, POC (and their subsequent decomposition and release to the atmosphere). Carbon isotope (14C and 13C) approaches have been used to estimate both rates and pathways for permafrost C mobilization and mineralization. Radiocarbon (14C) has been used to estimate the contribution of aged C to overall respiration or waterborne C export. We aim to contrast results from radiocarbon studies, in order to assess differences between ecosystems (contrasting wet and dry ecosystems), thaw histories (active layer deepening or thermokarst landforms), greenhouse gas considered (CO2 and CH4) and seasons. We propose to also contrast methodologies used for assessing the contribution of aged C to overall C balance, and include studies using 13C data. Biological fractionation of 13C during both uptake and decomposition has been taken advantage of both in order to aid the interpretation of 14C data and on its own to assess sources and mineralization pathways. For example, 13C data has been used to differentiate between CH4 production pathways, and the relative contribution of anaerobic CO2 production to overall respiration. Overall, carbon isotope research is proving highly valuable for our understanding of permafrost C dynamics following thaw, and there is a current need to synthesize the available literature.

  1. Late Norian δ13Corg record in the Tethyan realm: New clues on the complex Late Triassic carbon cycle from the Lagonegro Basin (southern Italy)

    Science.gov (United States)

    Zaffani, Mariachiara; Agnini, Claudia; Concheri, Giuseppe; Godfrey, Linda; Katz, Miriam; Maron, Matteo; Rigo, Manuel

    2016-04-01

    The Late Triassic (ca. 237-201 Ma) is characterized by complex and extreme environmental, climatic and biotic changes (e.g.: the break-up of the supercontinent Pangaea; the humid event known as the Carnian Pluvial Event; the End-Triassic mass extinction; the emplacement of the CAMP volcanism). A global δ13Corg curve for the Late Triassic would provide new clues on this perturbed time interval and would have the potential for global correlations. In particular, the few available data from North American successions define the late Norian (ca. 220-206 Ma) as a "chaotic carbon interval", with rapid vacillations of the carbon isotope values paired with low faunal diversity. Our goal is to reconstruct a global δ13Corg profile for the late Norian, as a contribution to the construction of a more complete global carbon isotope curve for the Late Triassic. For this purpose, we analyzed three sections from the Lagonegro Basin (southern Italy), originally located in the western Tethys, on the other side of the supercontinent Pangaea respect to the North America. The obtained δ13Corg profiles show four negative shifts correlatable with those of the North American record, suggesting that these carbon cycle perturbations have a widespread occurrence. These perturbations are associated with negative shifts of the 87Sr/86Sr, indicating that these global δ13Corg and 87Sr/86Sr negative excursions were possibly caused by emplacement of a Large Igneous Province (LIP). The input of volcanogenic CO2 to the atmosphere-ocean system is supported also by the 12C enrichment observed, as well as by the increase of atmospheric pCO2 inferred by different models for the Norian- Rhaetian interval. This Norian magmatic activity may be ascribed to the Angayucham province (Alaska, North America), a large oceanic plateau active ca. 214 Ma ±7 Myr, with an estimated volume comparable to other two Late Triassic LIPs: the Wrangellia and the CAMP.

  2. Doxorubicin conjugated functionalizable carbon dots for nucleus targeted delivery and enhanced therapeutic efficacy

    Science.gov (United States)

    Yang, Lei; Wang, Zheran; Wang, Ju; Jiang, Weihua; Jiang, Xuewei; Bai, Zhaoshi; He, Yunpeng; Jiang, Jianqi; Wang, Dongkai; Yang, Li

    2016-03-01

    Carbon dots (CDs) have shown great potential in imaging and drug/gene delivery applications. In this work, CDs functionalized with a nuclear localization signal peptide (NLS-CDs) were employed to transport doxorubicin (DOX) into cancer cells for enhanced antitumor activity. DOX was coupled to NLS-CDs (DOX-CDs) through an acid-labile hydrazone bond, which was cleavable in the weakly acidic intracellular compartments. The cytotoxicity of DOX-CD complexes was evaluated by the MTT assay and the cellular uptake was monitored using flow cytometry and confocal laser scanning microscopy. Cell imaging confirmed that DOX-CDs were mainly located in the nucleus. Furthermore, the complexes could efficiently induce apoptosis in human lung adenocarcinoma A549 cells. The in vivo therapeutic efficacy of DOX-CDs was investigated in an A549 xenograft nude mice model and the complexes exhibited an enhanced ability to inhibit tumor growth compared with free DOX. Thus, the DOX-CD conjugates may be exploited as promising drug delivery vehicles in cancer therapy.Carbon dots (CDs) have shown great potential in imaging and drug/gene delivery applications. In this work, CDs functionalized with a nuclear localization signal peptide (NLS-CDs) were employed to transport doxorubicin (DOX) into cancer cells for enhanced antitumor activity. DOX was coupled to NLS-CDs (DOX-CDs) through an acid-labile hydrazone bond, which was cleavable in the weakly acidic intracellular compartments. The cytotoxicity of DOX-CD complexes was evaluated by the MTT assay and the cellular uptake was monitored using flow cytometry and confocal laser scanning microscopy. Cell imaging confirmed that DOX-CDs were mainly located in the nucleus. Furthermore, the complexes could efficiently induce apoptosis in human lung adenocarcinoma A549 cells. The in vivo therapeutic efficacy of DOX-CDs was investigated in an A549 xenograft nude mice model and the complexes exhibited an enhanced ability to inhibit tumor growth compared

  3. Investigation of the degradation of 13C-labeled fungal biomass in soil - fate of carbon in a soil bioreactor system

    Science.gov (United States)

    Schweigert, Michael; Fester, Thomas; Miltner, Anja; Kaestner, Matthias

    2015-04-01

    Nutrient balances and degradation processes in boreal forests are mainly influenced by interactions of plant roots and ectomycorrhizal fungi. Plants benefit from nitrogen compounds provided by their symbiotic interaction partner. In return ectomycorrhiza are provided by large amounts of carbon from the plants which is used for the synthesis of hyphal networks in soil and for metabolic activity for nutrient uptake. Therefore, ectomycorrhizal fungi play a major role in ecosystems of boreal forests and are consequently an important sink for carbon by building large amount of mycelia. Recently, it has been shown that microbial biomass residues contribute significantly to soil organic matter formation. This suggests that also residues of ectomycorrhizal fungi may be an important source for soil organic matter formation in forest soils where these fungi are abundant. However, the fate of ectomycorrhizal biomass residues in soils is unknown. We therefore investigated the fate of ectomycorrhizal biomass in soil in a soil bioreactor system to quantify the contribution of this material to soil organic matter formation. As a model organism, we selected Laccaria bicolor, which was labelled by growing the fungus on 13C glucose. The stable isotope-labeled biomass was then homogenized and incubated in a podzol from a typical forest site in Central Germany. The fate of the labeled biomass was traced by analyzing the amount of 13C mineralized and the amount remaining in the soil. The fungal biomass carbon was mineralized rather rapidly during the first 50 days. Then the mineralization rate slowed down, but mineralization continued until the end of the experiment, when approximately 40% of the 13C was mineralized and 60% remained in soil. In addition, we analyzed biomolecules such as fatty acids to trace the incorporation of the L. bicolor-derived biomass carbon into other microorganisms and to identify potential primary consumers of fungal biomass. By these analyses, we found a

  4. delta 15N and non-carbonate delta 13C values for two petroleum source rock reference materials and a marine sediment reference material

    Science.gov (United States)

    Dennen, Kristin O.; Johnson, Craig A.; Otter, Marshall L.; Silva, Steven R.; Wandless, Gregory A.

    2006-01-01

    Samples of United States Geological Survey (USGS) Certified Reference Materials USGS Devonian Ohio Shale (SDO-1), and USGS Eocene Green River Shale (SGR-1), and National Research Council Canada (NRCC) Certified Marine Sediment Reference Material (PACS-2), were sent for analysis to four separate analytical laboratories as blind controls for organic rich sedimentary rock samples being analyzed from the Red Dog mine area in Alaska. The samples were analyzed for stable isotopes of carbon (delta13Cncc) and nitrogen (delta15N), percent non-carbonate carbon (Wt % Cncc) and percent nitrogen (Wt % N). SDO-1, collected from the Huron Member of the Ohio Shale, near Morehead, Kentucky, and SGR-1, collected from the Mahogany zone of the Green River Formation are petroleum source rocks used as reference materials for chemical analyses of sedimentary rocks. PACS-2 is modern marine sediment collected from the Esquimalt, British Columbia harbor. The results presented in this study are, with the exceptions noted below, the first published for these reference materials. There are published information values for the elemental concentrations of 'organic' carbon (Wt % Corg measured range is 8.98 - 10.4) and nitrogen (Wt % Ntot 0.347 with SD 0.043) only for SDO-1. The suggested values presented here should be considered 'information values' as defined by the NRCC Institute for National Measurement Reference Materials and should be useful for the analysis of 13C, 15N, C and N in organic material in sedimentary rocks.

  5. Targeting Antibodies to Carbon Nanotube Field Effect Transistors by Pyrene Hydrazide Modification of Heavy Chain Carbohydrates

    Directory of Open Access Journals (Sweden)

    Steingrimur Stefansson

    2012-01-01

    Full Text Available Many carbon nanotube field-effect transistor (CNT-FET studies have used immobilized antibodies as the ligand binding moiety. However, antibodies are not optimal for CNT-FET detection due to their large size and charge. Their size can prevent ligands from reaching within the Debye length of the CNTs and a layer of charged antibodies on the circuits can drown out any ligand signal. In an attempt to minimize the antibody footprint on CNT-FETs, we examined whether pyrene hydrazide modification of antibody carbohydrates could reduce the concentration required to functionalize CNT circuits. The carbohydrates are almost exclusively on the antibody Fc region and this site-specific modification could mediate uniform antibody orientation on the CNTs. We compared the hydrazide modification of anti-E. coli O157:H7 polyclonal antibodies to pyrenebutanoic acid succinimidyl ester-coated CNTs and carbodiimide-mediated antibody CNT attachment. Our results show that the pyrene hydrazide modification was superior to those methods with respect to bacteria detection and less than 1 nM labeled antibody was required to functionalize the circuits.

  6. Targeted delivery and controlled release of Paclitaxel for the treatment of lung cancer using single-walled carbon nanotubes.

    Science.gov (United States)

    Yu, Baodan; Tan, Li; Zheng, Runhui; Tan, Huo; Zheng, Lixia

    2016-11-01

    A new type of drug delivery system (DDS) based on single-walled carbon nanotubes (SWNTs) for controlled-release of the anti-cancer drug Paclitaxel (PTX) was constructed in this study. Chitosan (CHI) was non-covalently attached to the SWNTs to improve biocompatibility. Biocompatible hyaluronan was also combined to the outer CHI layer to realise the specific targeting property. The results showed that the release of PTX was pH-triggered and was better at lower pH (pH5.5). The modified SWNTs showed a significant improvement in intracellular reactive oxygen species (ROS), which may have enhanced mitogen-activated protein kinase activation and further promoted cell apoptosis. The results of western blotting indicated that the apoptosis-related proteins were abundantly expressed in A549 cells. Lactate dehydrogenase (LDH) release assay and cell viability assay demonstrated that PTX-loaded SWNTs could destroy cell membrane integrity, thus inducing lower cell viability of the A549 cells. Thus, this targeting DDS could effectively inhibit cell proliferation and kill A549 cells, is a promising system for cancer therapy. PMID:27524057

  7. Evaluation of a Carbonic Anhydrase IX-Targeted Near-Infrared Dye for Fluorescence-Guided Surgery of Hypoxic Tumors.

    Science.gov (United States)

    Lv, Peng-Cheng; Roy, Jyoti; Putt, Karson S; Low, Philip S

    2016-05-01

    Proof-of-principle studies in ovarian, lung, and brain cancer patients have shown that fluorescence-guided surgery can enable removal of otherwise undetectable malignant lesions, decrease the number of cancer-positive margins, and permit identification of disease-containing lymph nodes that would have normally evaded resection. Unfortunately, the current arsenal of tumor-targeted fluorescent dyes does not permit identification of all cancers, raising the need to design new tumor-specific fluorescent dyes to illuminate the currently undetectable cancers. In an effort to design a more universal fluorescent cancer imaging agent, we have undertaken to synthesize a fluorophore that could label all hypoxic regions of tumors. We report here the synthesis, in vitro binding, and in vivo imaging of a near-infrared (NIR) fluorescent dye that is targeted to carbonic anhydrase IX (CA IX), i.e., a widely accepted marker of hypoxic tissues. The low molecular weight NIR probe, named Hypoxyfluor, is shown to bind CA IX with high affinity and accumulate rapidly and selectively in CA IX positive tumors. Because nearly all human cancers contain hypoxic regions that express CA IX abundantly, this NIR probe should facilitate surgical resection of a wide variety of solid tumors. PMID:27043317

  8. Study the structure of neutron deficient carbon isotopes: 10C and 11C. Elastic and inelastic scattering on proton target

    International Nuclear Information System (INIS)

    This work is devoted to the study of the structure of neutron-deficient carbon isotopes: 10C and 11C. A theoretical model predicts a special behaviour for these nuclei: different deformations for neutron and proton densities. To test these predictions and to obtain information on the structure of these nuclei, we measured angular distribution for elastic and inelastic scattering on proton target with inverse kinematics at 40 MeV per nucleon. The angular distribution is deduced from the proton energy and angle scattering, measured by the MUST detector. Experimental set-up is completed with plastic detectors for scattered nucleus identification and with two CATS detectors for measurement of position and angle for each beam particle on the target. Angular distributions are calculated with an analytic method. This method is tested with a simulation and with 12C + p scattering analysis. Angular distributions are analysed in terms of a complex microscopic potential JLM with different microscopic matter densities. Elastic scattering gives an information on 10C and 11C matter root mean square radii. Both radii are larger than the one for the stable 12C isotope. Inelastic scattering is treated in DWBA approximation with microscopic transition densities. 10C inelastic scattering gives an information on neutron contribution of nucleus excitation. With 11C inelastic scattering, we could constrain transition densities and we could extract an information on the type of the transition. However, it is very difficult to confirm or to annul predictions of different deformations for proton and neutrons densities. (author)

  9. Crucial role of the biological barrier at the primary targeted organs in controlling the translocation and toxicity of multi-walled carbon nanotubes in the nematode Caenorhabditis elegans

    Science.gov (United States)

    Wu, Qiuli; Li, Yinxia; Li, Yiping; Zhao, Yunli; Ge, Ling; Wang, Haifang; Wang, Dayong

    2013-10-01

    Multi-walled carbon nanotubes (MWCNTs) can be translocated into the targeted organs of organisms. We employed a model organism of the nematode Caenorhabditis elegans to investigate the role of a biological barrier at the primary targeted organs in regulating the translocation and toxicity formation of MWCNTs. A prolonged exposure to MWCNTs at predicted environmental relevant concentrations caused adverse effects associated with both the primary and secondary targeted organs on nematodes. The function of PEGylated modification in reducing MWCNTs toxicity might be mainly due to the suppression of their translocation into secondary targeted organs through the primary targeted organs. A biological barrier at the primary targeted organs contributed greatly to the control of MWCNTs translocation into secondary targeted organs, as indicated by functions of Mn-SODs required for prevention of oxidative stress in the primary targeted organs. Over-expression of Mn-SODs in primary targeted organs effectively suppressed the translocation and toxicity of MWCNTs. Our work highlights the crucial role of the biological barrier at the primary targeted organs in regulating the translocation and toxicity formation of MWCNTs. Our data also shed light on the future development of engineered nanomaterials (ENMs) with improved biocompatibility and design of prevention strategies against ENMs toxicity.Multi-walled carbon nanotubes (MWCNTs) can be translocated into the targeted organs of organisms. We employed a model organism of the nematode Caenorhabditis elegans to investigate the role of a biological barrier at the primary targeted organs in regulating the translocation and toxicity formation of MWCNTs. A prolonged exposure to MWCNTs at predicted environmental relevant concentrations caused adverse effects associated with both the primary and secondary targeted organs on nematodes. The function of PEGylated modification in reducing MWCNTs toxicity might be mainly due to the suppression

  10. A spectral line survey in the 2 mm and 1.3 mm windows toward the carbon rich envelope of IRC +10216

    CERN Document Server

    He, J H; Kwok, S; Müller, H S P; Zhang, Y; Hasegawa, T; Peng, T C; Huang, Y C

    2008-01-01

    We present the results of our spectral line surveys in the 2 mm and 1.3 mm windows toward the carbon rich envelope of IRC +10216. Totally 377 lines are detected, among which 360 lines are assigned to 57 known molecules (including 29 rare isotopomers and 2 cyclic isomers). Only 17 weak lines remain unidentified. Rotational lines of isotopomers 13CCH and c-13CCCH are detected for the first time in IRC +10216. The detection of the formaldehyde lines in this star is also confirmed. Possible abundance difference among the three 13C substituted isotopic isomers of HC3N is reported. Isotopic ratios of C and O are confirmed to be non-solar while those of S and Si to be nearly solar. Column densities have been estimated for 15 molecular species. Modified spectroscopic parameters have been calculated for NaCN, Na13CN, KCN and SiC2. Transition frequencies from the present observations were used to improve the spectroscopic parameters of Si13CC, 29SiC2 and 30SiC2.

  11. Organic matter turnover in reservoirs of the Harz Mountains (Germany): evidence from 13C/12C changes in dissolved inorganic carbon

    Science.gov (United States)

    Barth, Johannes A. C.; Nenning, Franziska; van Geldern, Robert; Mader, Michael; Friese, Kurt

    2014-05-01

    The Harz Mountains in Germany host several reservoirs for drinking water and electricity supply, the largest of which is the Rappbode System with its two pre-reservoirs. They are the Hassel and the Rappbode pre-reservoirs that have about the same size. These pre-reservoirs were investigated in a comparative study in order to quantify turnover of dissolved organic carbon (DOC) as a representative for organic matter. The objective was to find out how organic matter turnover in these reservoirs may affect dissolved inorganic carbon (DIC) and related CO2 dynamics. Depth profiles of dissolved organic and inorganic carbon (DOC and DIC) were established together with their carbon stable isotope distributions (expressed as δ13CDIC and δ13CDOC). Our results showed up to 104 % increase of DIC contents by organic matter turnover when calculated via isotope mass balances. This contrasted observations of DIC concentration differences between waters collected at the surface and at 12 m depth. These concentration comparisons showed much less DIC increases, and in some cases even decreases, between surface and bottom waters. Such discrepancies could be explained by formation of CO2 at depths below the photic zone that reached calculated values above 7000 ppmV. Such high CO2 concentrations may have reduced the DIC pool by upwards migration. Despite such a concentration decrease, turnover of organic matter has likely incorporated its isotope signal into the DIC pool. While not all DOC present was transposed to DIC, other forms of organic matter from sediments may also have transferred their isotope ratio on the DIC pool. However, with its stable isotope ratio of -28.5 permille the measured DOC was representative of C3 plants and can be assumed as a proxy for other forms of sedimentary carbon including carbon from pore waters and particulate organic matter. Other carbon turnover, including DOC leaching, increased import to the reservoirs after precipitation events and

  12. Synthesis of methyl [(chloro-2 ethyl)-3 nitroso-3 Ureido]-3 Didesoxy-2,3 α-D-Arabino-hexopyrannoside labelled with carbon-14 or carbon-13 (CY 233 - SR 90008)

    International Nuclear Information System (INIS)

    CY 233 (Ecomustine or SR 90098) is a new antitumour nitrosourea: it is characterized by a 2-chloroethylnitrosourea substituent on a dideoxycarbohydrate. It has been labelled with 14C on a) the carbonyl group of the urea in four stages starting with 14COCl2, b) the second carbon of the chloroethyl group in four stages starting with [14C] ethanolamine, and c) on the methyl group on the anomeric centre of the carbohydrate in three stages starting with 14CH3OH. The final position was also labelled with 13C starting with 13CH3OH. These differently labelled compounds are suitable for mechanistic studies of antitumour activity. (author)

  13. Stable carbon isotope analysis ({delta}{sup 13}C values) of polybrominated diphenyl ethers and their UV-transformation products

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfelder, Natalie; Bendig, Paul [University of Hohenheim, Institute of Food Chemistry (170b), Garbenstr. 28, D-70599 Stuttgart (Germany); Vetter, Walter, E-mail: walter.vetter@uni-hohenheim.de [University of Hohenheim, Institute of Food Chemistry (170b), Garbenstr. 28, D-70599 Stuttgart (Germany)

    2011-10-15

    Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the {delta}{sup 13}C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in {sup 13}C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in {sup 13}C because of more stable bonds between {sup 13}C and bromine. As a result, the {delta}{sup 13}C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the {delta}{sup 13}C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios <1 are typical for native congeners (e.g. in DE-71) while the reversed ratio (>1) is typical of transformation products. - Highlights: > {delta}{sup 13}C values of PBDEs were determined by means of compound specific isotope analysis. > PBDEs in technical mixtures were the more depleted in {sup 13}C the higher they were brominated. > Solutions of individual PBDEs and technical PBDE mixtures were irradiated by UV light. > {delta}{sup 13}C values of irradiated PBDEs and technical PBDEs progressed diametrically. > Ratios of the {delta}{sup 13}C values were used to distinguish native from transformed PBDEs. - Diametrically progressing {delta}{sup 13}C values in technical mixtures and UV-transformation products of DE-79 may be useful for source appointment of PBDEs in environmental samples

  14. An atomic electronegative distance vector and carbon-13 nuclear magnetic resonance chemical shifts of alcohols and alkanes

    Institute of Scientific and Technical Information of China (English)

    LIU, Shu-Shea; XIA, Zhi-Ning; CAI, Shao-Xi; LIU, Yan

    2000-01-01

    A novel atomic electronegative distance vector (AEDV) has been developed to express the chemical environment of various chemically equivalent carbon atoms in alcohols and alkanes.Combining AEDV and γ parameter, four five-parameter Iinear relationship equations of chemical shift for four types of carbon atoms are created by using multiple linear regression.Correlation coefficients are R = 0.9887, 0.9972, 0.9978 and 0.9968 and roots of mean square error are RMS = 0.906, 0.821, 1.091and 1.091of four types of carbons, i.e., type1,2, 3, and 4 for primary, secondary, tertiary, and quaternary carbons, respectively. The stability and prediction capacity for external samples of four models have been tested by cross- validation.

  15. Study of carbon nitride compounds synthesised by co-implantation of 13C and 14N in copper at different temperatures

    International Nuclear Information System (INIS)

    Research highlights: → Simultaneous implantation of 13C and 14N in copper were performed to synthesise CNx compounds. → The formation of fullerene-like CNx compounds was highlighted by XPS and TEM. → Only about 20% of the implanted 14N atoms are contained in the FL CxNy structures. → The exceeding of implanted nitrogen precipitates in large N2 gas bubbles. → A growth model for the FL CxNy structures is proposed. - Abstract: Carbon nitride compounds have been synthesised in copper by simultaneous high fluence (1018 at. cm-2) implantation of 13C and 14N ions. During the implantation process, the substrate temperature was maintained at 25, 250, 350 or 450 deg. C. Depth profiles of 13C and 14N were determined using the non-resonant nuclear reactions (NRA) induced by a 1.05 MeV deuteron beam. The retained doses were deduced from NRA measurements and compared to the implanted fluence. The chemical bonds between carbon and nitrogen were studied as a function of depth and temperature by X-ray photoelectron spectroscopy (XPS). The curve fitting of C 1s and N 1s core level photoelectron spectra reveal different types of C-N bonds and show the signature of N2 molecules. The presence of nitrogen gas bubbles in copper was highlighted by mass spectroscopy. The structure of carbon nitride compounds was characterised by transmission electron microscopy (TEM). For that purpose, cross-sectional samples were prepared using a focused ion beam (FIB) system. TEM observations showed the presence of small amorphous carbon nitride 'nano-capsules' and large gas bubbles in copper. Based on our observations, we propose a model for the growth of these nano-objects. Finally, the mechanical properties of the implanted samples were investigated by nano-indentation.

  16. Fluxes and 13C isotopic composition of dissolved carbon and pathways of methanogenesis in a fen soil exposed to experimental drought

    Directory of Open Access Journals (Sweden)

    C. Blodau

    2008-10-01

    Full Text Available Peatlands contain a carbon stock of global concern and significantly contribute to the global methane burden. The impact of drought and rewetting on carbon cycling in peatland ecosystems is thus currently debated. We studied the impact of experimental drought and rewetting on intact monoliths from a temperate fen over a period of ~300 days, using a permanently wet treatment and two treatments undergoing drought for 50 days. In one of the mesocosms, vegetation had been removed. Net production of CH4 was calculated from mass balances in the peat and emission using static chamber measurements. Results were compared to 13C isotope budgets of CO2 and CH4 and energy yields of acetoclastic and hydrogenotrophic methanogenesis. Drought retarded methane production after rewetting for days to weeks and promoted methanotrophic activity. Based on isotope and flux budgets, aerobic soil respiration contributed 32–96% in the wet treatment and 86–99% in the other treatments. Drying and rewetting did not shift methanogenic pathways according to δ13C ratios of CH4 and CO2. Although δ13C ratios indicated a prevalence of hydrogenotrophic methanogenesis, free energies of this process were small and often positive on the horizon scale. This suggests that methane was produced very locally. Fresh plant-derived carbon input apparently supported respiration in the rhizosphere and sustained methanogenesis in the unsaturated zone, according to a 13C-CO2 labelling experiment. The study documents that drying and rewetting in a rich fen soil may have little effect on methanogenic pathways, but result in rapid shifts between methanogenesis and methanotrophy. Such shifts may be promoted by roots and soil heterogeneity, as hydrogenotrophic methanogenesis occurred locally even when conditions were not conducive for this process in the bulk peat.

  17. Seasonal and inter-annual variability in 13C composition of ecosystem carbon fluxes in the U.S. Southern Great Plains

    Energy Technology Data Exchange (ETDEWEB)

    Torn, M.S.; Biraud, S.; Still, C.J.; Riley, W.J.; Berry, J.A.

    2010-09-22

    The {delta}{sup 13}C signature of terrestrial carbon fluxes ({delta}{sub bio}) provides an important constraint for inverse models of CO{sub 2} sources and sinks, insight into vegetation physiology, C{sub 3} and C{sub 4} vegetation productivity, and ecosystem carbon residence times. From 2002-2009, we measured atmospheric CO{sub 2} concentration and {delta}{sup 13}C-CO{sub 2} at four heights (2 to 60 m) in the U.S. Southern Great Plains (SGP) and computed {delta}{sub bio} weekly. This region has a fine-scale mix of crops (primarily C{sub 3} winter wheat) and C{sub 4} pasture grasses. {delta}{sub bio} had a large and consistent seasonal cycle of 6-8{per_thousand}. Ensemble monthly mean {delta}{sub bio} ranged from -25.8 {+-} 0.4{per_thousand} ({+-}SE) in March to -20.1 {+-} 0.4{per_thousand} in July. Thus, C{sub 3} vegetation contributed about 80% of ecosystem fluxes in winter-spring and 50% in summer-fall. In contrast, prairie-soil {delta}{sub 13}C values were about -15{per_thousand}, indicating that historically the region was dominated by C{sub 4} vegetation and had more positive {delta}{sub bio} values. Based on a land-surface model, isofluxes ({delta}{sub bio} x NEE) in this region have large seasonal amplitude because {delta}{sub bio} and net ecosystem exchange (NEE) covary. Interannual variability in isoflux was driven by variability in NEE. The large seasonal amplitude in {delta}{sub bio} and isoflux imply that carbon inverse analyses require accurate estimates of land cover and temporally resolved {sup 13}CO{sub 2} and CO{sub 2} fluxes.

  18. Statistical analysis of a corrosion inhibitor family on three steel surfaces (duplex, super-13 and carbon) in hydrochloric acid solutions

    International Nuclear Information System (INIS)

    Previous studies have addressed the experimental and theoretical investigation of the inhibition corrosion efficiencies (ICE) of single metal surfaces. Along this line we carried out calculations concerning to 23 compounds on three different single-steel surfaces, duplex, super-13 and the carbon steel in hydrochloric acid (15% w/v) solutions. The overall experiment is composed of 69 results of weight loss ICEs at 60 deg. C for amines, alcohols, thiourea and its derivatives acting as corrosion inhibitors for three steel surfaces. In these studies ICEs were correlated with group and quantum AM1 descriptors through the use of three different statistical methodologies based on calibration and validation of regular and modified OLS and PLS (partial least squares) methods. All calculations have shown better results using weight isoesteric Langmuir adsorption function (WILA function), ln(θM/(1-θ)) or ln Kads, calculated from the weight loss data as the response function. The function -log(i) has been used, as well, on all comparisons. Variables describing the metal were added to the previous set of group and quantum IC variables and several models have been designed to fit the three-steel problem. Simple products of metal and IC variables with 250 (25 x 10) products were tested as model I. Selection of the best variable set was carried out for the calibration and validation procedures and these calculations indicated very few descriptors in common, i.e. each particular selection (calibration or validation) finds its own optimal descriptor set. The overall results showed excellent correlations with R2 values between 0.80 and 0.96 and a Q2 values from 0.75 to 0.93. We are unaware of any similar QSPR study on the steels here studied, and neither the study of such massive amount of data concerning molecular inhibitors on three different steel surfaces. Our best result for the second-order cross-validation descriptor selection employs 29 variables, Y29. The results

  19. Turnover of carbon in the {sup 13}C-urea breath test for the detection of Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Vladimir E.; Andreazzi, Mariana; Cury, Caio S.; Bassetto Junior, Carlos A.Z.; Rodrigues, Maria A.M.; Ducatti, Carlos, E-mail: vladimir@ibb.unesp.br, E-mail: ducatti@ibb.unesp.br, E-mail: mariana.andreazazi@gmail.com, E-mail: caiocury@hotmail.com, E-mail: juniorbassett@hotmail.com, E-mail: mariar@fmb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

    2013-07-01

    To obtain a standard protocol for the application of {sup 13}C-urea breath test ({sup 13}C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of {sup 13}C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the {sup 13}C in the {sup 13}C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio {sup 13}C/{sup 12}C in expired CO{sub 2} from patients infected with H. pylori and subjected to {sup 13}C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  20. Observing the Arctic Carbon Feedback: Regional scale methane flux measurements over the Alaskan North Slope using airplane flux observations and in situ measurements of δ13CH4.

    Science.gov (United States)

    Healy, C. E.; Sayres, D. S.; Dobosy, R.; Dumas, E. J.; Munster, J. B.; Kochendorfer, J.; Wilkerson, J.; Baker, B.; Dubey, M. K.; Anderson, J. G.

    2015-12-01

    One of the most powerful positive feedback mechanisms to anthropogenic climate change postulated is the increase in carbon emissions from polar-regions. Warmer temperatures at the poles is predicted to increase the rate of methanogensesis in thawing permafrost soils as well as destabilize the network of arctic marine and terrestrial methane hydrates. Recent estimates put the quantity of organic carbon stored in soils in the northern permafrost zone around 1,700 Pg of C, which is well in excess of the maximum carbon emissions necessary to limit global average temperature increase to only 2 C° (260-410 Pg of C between 2011 and 2100 as CO2). However, many climate models used to forecast changes in average global temperature and inform policy decisions do not take into account arctic carbon feedback. This is largely due in part to the daunting observational challenge presented by observing methane fluxes in the Arctic. An ideal measurement system must be able to distinguish between biological and anthropogenic methane sources, have the ability to cover large spatial ranges, and have the sensitivity to distinguish changes from season to season, and year to year. The FOCAL platform has been engineered to address these challenges and help bridge the gap in spatial coverage between ground based and inverse modelling studies. It consists of a small aircraft equipped with the best atmospheric turbulence (BAT) probe, and gas sensors for in situ measurements of CH4, CO2, δ13CH4, δ13CO2 to make regional scale surface eddy-covariance flux measurements of methane and carbon dioxide as well as their stable isotopologues. We will present data from the initial FOCAL flight series in August 2013 based out of Deadhorse, AK, including CH4 concentration and running flux data, as well as in situ δ13CH4 observations to gain mechanistic insight. With the FOCAL platform we were able to dramatically extend regional coverage of methane flux observations beyond what can normally be observe

  1. Calcium isotope constraints on the marine carbon cycle and CaCO3 deposition during the late Silurian (Ludfordian) positive δ13C excursion

    Science.gov (United States)

    Farkaš, Juraj; Frýda, Jiří; Holmden, Chris

    2016-10-01

    This study investigates calcium isotope variations (δ 44 / 40 Ca) in late Silurian marine carbonates deposited in the Prague Basin (Czech Republic), which records one of the largest positive carbon isotope excursion (CIE) of the entire Phanerozoic, the mid-Ludfordian CIE, which is associated with major climatic changes (abrupt cooling) and global sea-level fluctuations. Our results show that during the onset of the CIE, when δ13 C increases rapidly from ∼0‰ to ∼8.5‰, δ 44 / 40Ca remains constant at about 0.3 ± 0.1 ‰ (relative to NIST 915a), while 87Sr/86Sr in well-preserved carbonates are consistent with a typical Ludfordian seawater composition (ranging from ∼0.70865 to ∼0.70875). Such decoupling between δ13 C and δ 44 / 40Ca trends during the onset of the CIE is consistent with the expected order-of-magnitude difference in the residence times of Ca (∼106yr) and C (∼105yr) in the open ocean, suggesting that the mid-Ludfordian CIE was caused by processes where the biogeochemical pathways of C and Ca in seawater were mechanistically decoupled. These processes may include: (i) near shore methanogenesis and photosynthesis, (ii) changes in oceanic circulation and stratification, and/or (iii) increased production and burial of organic C in the global ocean. The latter, however, is unlikely due to the lack of geological evidence for enhanced organic C burial, and also because of unrealistic parameterization of the ocean C cycle needed to generate the observed CIE over the relatively short time interval. In contrast, higher up in the section where δ13 C shifts back to pre-excursion baseline values, there is a correlated shift to higher δ 44 / 40Ca values. Such coupling of the records of Ca and C isotope changes in this part of the study section is inconsistent with the abovementioned differences in oceanic Ca and C residence times, indicating that the record of δ 44 / 40Ca changes does not faithfully reflect the evolution of the oceanic Ca

  2. Application of solid state silicon-29 and carbon-13 nuclear magnetic resonance spectroscopy to the characterization of inorganic matter-humic complexes in Athabasca oil sands

    International Nuclear Information System (INIS)

    In Athabasca oil sands there is a fraction of non-crystalline solids tightly bound to humic matter. It is believed, that the presence of this fraction, which resists subsequent wetting by water, introduces serious problems in bitumen recovery when using water based processes. In the present work, 29Si and 13C solid state magic angle spinning (MAS) NMR techniques were applied to characterize these solids which were isolated from Athabasca oil sands of estuarine and marine origin. On the basis of 29Si results it is suggested that there is a short-range disorder in these samples. It is also shown that aluminum is present in the nearest-neighbor environment of the silicon atoms, thus demonstrating that these solids are comprised of disordered alumino-silicates (allophanes). 13C CP/MAS NMR spectra of demineralized inorganic matter-humic complexes derived from both estuarine and marine oil sands indicate that the distribution of carbon types in each region of the spectra is similar, with aromatic carbon being the predominant type of carbon

  3. Terrestrial carbon cycle responses to drought and climate stress: New insights using atmospheric observations of CO2 and delta13C

    Science.gov (United States)

    Alden, Caroline B.

    Atmospheric concentrations of carbon dioxide (CO2) continue to rise well into the second decade of the new millennium, in spite of broad-scale human understanding of the impacts of fossil fuel emissions on the earth's climate. Natural sinks for CO2 that are relevant on human time scales---the world's oceans and land biosphere---appear to have kept pace with emissions. The continuously increasing strength of the land biosphere sink for CO2 is surpassing expectations given our understanding of the CO2 fertilization and warming effects on the balance between photosynthesis and respiration, especially in the face of ongoing forest degradation. The climate and carbon cycle links between the atmosphere and land biosphere are not well understood, especially at regional (100 km to 10,000 km) scales. The climate modulating effects of changing plant stomatal conductance in response to temperature and water availability is a key area of uncertainty. Further, the differential response to climate change of C3 and C4 plant functional types is not well known at regional scales. This work outlines the development of a novel application of atmospheric observations of delta13C of CO2 to investigate the links between climate and water and carbon cycling and the integrated responses of C3 and C4 ecosystems to climate variables. A two-step Bayesian batch inversion for 3-hourly, 1x1º CO2 fluxes (step one), and for 3-hourly 1x1º delta13C of recently assimilated carbon (step two) is created here for the first time, and is used to investigate links between regional climate indicators and changes in delta13C of the biosphere. Results show that predictable responses of regional-scale, integrated plant discrimination to temperature, precipitation and relative humidity anomalies can be recovered from atmospheric signals. Model development, synthetic data simulations to test sensitivity, and results for the year 2010 are presented here. This dissertation also includes two other applications

  4. Target particle and heat loads in low-triangularity L-mode plasmas in JET with carbon and beryllium/tungsten walls

    NARCIS (Netherlands)

    Groth, M.; Brezinsek, S.; Belo, P.; Corrigan, G.; Harting, D.; Wiesen, S.; Beurskens, M. N. A.; Brix, M.; Clever, M.; Coenen, J. W.; Eich, T.; Flanagan, J.; Giroud, C.; Huber, A.; Jachmich, S.; Kruezi, U.; Lehnen, M.; Lowry, C.; Maggi, C. F.; Marsen, S.; Meigs, A. G.; Sergienko, G.; Sieglin, B.; Silva, C.; Sirinelli, A.; Stamp, M. F.; van Rooij, G. J.

    2013-01-01

    Divertor radiation profiles, and power and particle fluxes to the target have been measured in attached \\{JET\\} L-mode plasmas with carbon and beryllium/tungsten wall materials. In the beryllium/tungsten configuration, factors of 2–3 higher power loads and peak temperatures at the low field side tar

  5. Application of nitrogen and carbon stable isotopes (δ(15N and δ(13C to quantify food chain length and trophic structure.

    Directory of Open Access Journals (Sweden)

    Matthew J Perkins

    Full Text Available Increasingly, stable isotope ratios of nitrogen (δ(15N and carbon (δ(13C are used to quantify trophic structure, though relatively few studies have tested accuracy of isotopic structural measures. For laboratory-raised and wild-collected plant-invertebrate food chains spanning four trophic levels we estimated nitrogen range (NR using δ(15N, and carbon range (CR using δ(13C, which are used to quantify food chain length and breadth of trophic resources respectively. Across a range of known food chain lengths we examined how NR and CR changed within and between food chains. Our isotopic estimates of structure are robust because they were calculated using resampling procedures that propagate variance in sample means through to quantified uncertainty in final estimates. To identify origins of uncertainty in estimates of NR and CR, we additionally examined variation in discrimination (which is change in δ(15N or δ(13C from source to consumer between trophic levels and among food chains. δ(15N discrimination showed significant enrichment, while variation in enrichment was species and system specific, ranged broadly (1.4‰ to 3.3‰, and importantly, propagated variation to subsequent estimates of NR. However, NR proved robust to such variation and distinguished food chain length well, though some overlap between longer food chains infers a need for awareness of such limitations. δ(13C discrimination was inconsistent; generally no change or small significant enrichment was observed. Consequently, estimates of CR changed little with increasing food chain length, showing the potential utility of δ(13C as a tracer of energy pathways. This study serves as a robust test of isotopic quantification of food chain structure, and given global estimates of aquatic food chains approximate four trophic levels while many food chains include invertebrates, our use of four trophic level plant-invertebrate food chains makes our findings relevant for a majority

  6. Changes in carbon uptake and allocation patterns in Quercus robur seedlings in response to elevated CO2 and water stress: an evaluation with 13C labelling

    International Nuclear Information System (INIS)

    A semi-closed (CO2)-C-13 labelling system (1.5% C-13) was used to assess both carbon uptake and allocation within pedunculate oak seedlings (Quercus robur L) grown under ambient (350 vpm) and elevated (700 vpm) atmospheric CO2 concentration ([CO2]) and in either well-watered or droughted conditions. Pulse-chase C-13 labelling data highlighted the direct positive effect of elevated CO2 on photosynthetic carbon acquisition. Consequently, in well-watered conditions, CO2-enriched plants produced 1.52 times more biomass (dry mass at harvest) and 1.33 times more dry root matter (coarse plus fine roots) over the 22-week growing period than plants grown under ambient [CO2]. The root/shoot biomass ratio was decreased both by drought and [CO2], despite lower N concentrations in CO2-enriched plants. However, both long-term and short-term C allocation to fine roots were not altered by CO2, and relative specific allocation (RSA), a parameter expressing sink strength, was hip her in all plant organs under 700 vpm compared to 350 vpm. Results showed that C availability for growth and metabolic processes was greater in fine roots of oaks grown under an elevated CO2 atmosphere irrespective of soil water availability

  7. Solid state 13C NMR and carbon isotope studies of the coupling of primary and secondary productivity in a Florida estuary

    International Nuclear Information System (INIS)

    The mechanisms by which primary producers fuel the growth of secondary consumers (e.g. fish and shell fish) in estuaries is poorly understood at this time. The authors have attempted to quantify the relative importance of detrital vs. planktonic food webs which support mariculture in the Ochlocknee River and Bay in Northwest Florida using stable carbon isotopes and solid state 13C NMR spectroscopy. Due to isotopic fractionation caused by different enzymatic pathways of carbon dioxide uptake, primary producers are imprinted with distinctive 13C/12C isotopic ratios. Stable isotopic ratios are imprints, or signatures, which are passed on to the next higher trophic level (you are what you eat). They have been combining isotopic tracing of food webs in estuaries with characterization of complex macromolecular particulates by cross polarization - magic angle spinning 13C NMR. In this talk they will demonstrate how the combination of these techniques can differentiate the relative importance of terrestrial input of organic matter vs. in situ estuarine production as a food source for estuarine consumers

  8. Application of δ13C and δ15N isotopic signatures of organic matter fractions sequentially separated from adjacent arable and forest soils to identify carbon stabilization mechanisms

    Directory of Open Access Journals (Sweden)

    M. Sommer

    2011-10-01

    Full Text Available Identifying the chemical mechanisms behind soil carbon bound in organo-mineral complexes is necessary to determine the degree to which soil organic carbon is stabilized belowground. Analysis of δ13C and δ15N isotopic signatures of stabilized OM fractions along with soil mineral characteristics may yield important information about OM-mineral associations and their processing history. We anlayzed the δ13C and δ15N isotopic signatures from two organic matter (OM fractions along with soil mineral proxies to identify the likely binding mechanisms involved. We analyzed OM fractions hypothesized to contain carbon stabilized through organo-mineral complexes: (1 OM separated chemically with sodium pyrophosphate (OM(PY and (2 OM occluded in micro-structures found in the chemical extraction residue (OM(ER. Because the OM fractions were separated from five different soils with paired forest and arable land use histories, we could address the impact of land use change on carbon binding and processing mechanisms. We used partial least squares regression to analyze patterns in the isotopic signature of OM with established mineral and chemical proxies indicative for certain binding mechanisms. We found different mechanisms predominate in each land use type. For arable soils, the formation of OM(PY-Ca-mineral associations was identified as an important OM binding mechanism. Therefore, we hypothesize an increased stabilization of microbial processed OM(PY through Ca2+ interactions. In general, we found the forest soils to contain on average 10% more stabilized carbon relative to total carbon stocks, than the agricultural counter part. In forest soils, we found a positive relationship between isotopic signatures of OM(PY and the ratio of soil organic carbon content to soil surface area (SOC/SSA. This indicates that the OM(PY fractions of forest soils represent layers of slower exchange not directly attached to mineral surfaces. From the isotopic composition

  9. Synthesis and evaluation of single-wall carbon nanotube-paclitaxel-folic acid conjugate as an anti-cancer targeting agent.

    Science.gov (United States)

    Tavakolifard, Sara; Biazar, Esmaeil; Pourshamsian, Khalil; Moslemin, Mohammad H

    2016-08-01

    Single-wall carbon nanotubes (SWCNT) represent a novel nanomaterial applied in various nanotechnology fields because of their surface chemistry properties and high drug cargo capacity. In this study, SWCNT are pre-functionalized covalently with paclitaxel (PTX) - an anticancer drug, and folic acid (FA), as a targeting agent for many tumors. The samples are investigated and evaluated by different analyses such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), absorption spectroscopic measurements (UV-Visible), elemental analysis, and cell analyses with cancer cell line cultures. The results show good conjugation of the targeting molecule and the anticancer drug on the surface of the carbon nanotubes (CNT). This work demonstrates that the SWCNT-PTX-FA system is a potentially useful system for the targeted delivery of anticancer drugs. PMID:25783856

  10. A carbon-13 NMR spin-lattice relaxation study of the molecular conformation of the nootropic drug 2-oxopyrrolidin-1-ylacetamide

    Science.gov (United States)

    Baldo, M.; Grassi, A.; Guidoni, L.; Nicolini, M.; Pappalardo, G. C.; Viti, V.

    The spin-lattice relaxation times ( T1) of carbon-13 resonances of the drug 2-oxopyrrolidin- 1-ylacetamide ( 2OPYAC) were determined in CDCl 3 + DMSO and H 2O solutions to investigate the internal conformational flexibility. The measured T1s for the hydrogen-bearing carbon atoms of the 2-pyrrolidone ring fragment were diagnostic of a rigid conformation with respect to the acetamide linked moiety. The model of anisotropic reorientation of a rigid body was used to analyse the measured relaxation data in terms of a single conformation. Owing to the small number of T1 data available the fitting procedure for each of the possible conformations failed. The structure corresponding to the rigid conformation was therefore considered to be the one that is strongly stabilized by internal hydrogen bonding as predicted on the basis of theoretical MO ab initio quantum chemical calculations.

  11. Non-targeted detection of chemical contamination in carbonated soft drinks using NMR spectroscopy, variable selection and chemometrics

    Energy Technology Data Exchange (ETDEWEB)

    Charlton, Adrian J. [Department for Environment, Food and Rural Affairs, Central Science Laboratory, Sand Hutton, York YO41 1LZ (United Kingdom)], E-mail: adrian.charlton@csl.gov.uk; Robb, Paul; Donarski, James A.; Godward, John [Department for Environment, Food and Rural Affairs, Central Science Laboratory, Sand Hutton, York YO41 1LZ (United Kingdom)

    2008-06-23

    An efficient method for detecting malicious and accidental contamination of foods has been developed using a combined {sup 1}H nuclear magnetic resonance (NMR) and chemometrics approach. The method has been demonstrated using a commercially available carbonated soft drink, as being capable of identifying atypical products and to identify contaminant resonances. Soft-independent modelling of class analogy (SIMCA) was used to compare {sup 1}H NMR profiles of genuine products (obtained from the manufacturer) against retail products spiked in the laboratory with impurities. The benefits of using feature selection for extracting contaminant NMR frequencies were also assessed. Using example impurities (paraquat, p-cresol and glyphosate) NMR spectra were analysed using multivariate methods resulting in detection limits of approximately 0.075, 0.2, and 0.06 mM for p-cresol, paraquat and glyphosate, respectively. These detection limits are shown to be approximately 100-fold lower than the minimum lethal dose for paraquat. The methodology presented here is used to assess the composition of complex matrices for the presence of contaminating molecules without a priori knowledge of the nature of potential contaminants. The ability to detect if a sample does not fit into the expected profile without recourse to multiple targeted analyses is a valuable tool for incident detection and forensic applications.

  12. Non-targeted detection of chemical contamination in carbonated soft drinks using NMR spectroscopy, variable selection and chemometrics

    International Nuclear Information System (INIS)

    An efficient method for detecting malicious and accidental contamination of foods has been developed using a combined 1H nuclear magnetic resonance (NMR) and chemometrics approach. The method has been demonstrated using a commercially available carbonated soft drink, as being capable of identifying atypical products and to identify contaminant resonances. Soft-independent modelling of class analogy (SIMCA) was used to compare 1H NMR profiles of genuine products (obtained from the manufacturer) against retail products spiked in the laboratory with impurities. The benefits of using feature selection for extracting contaminant NMR frequencies were also assessed. Using example impurities (paraquat, p-cresol and glyphosate) NMR spectra were analysed using multivariate methods resulting in detection limits of approximately 0.075, 0.2, and 0.06 mM for p-cresol, paraquat and glyphosate, respectively. These detection limits are shown to be approximately 100-fold lower than the minimum lethal dose for paraquat. The methodology presented here is used to assess the composition of complex matrices for the presence of contaminating molecules without a priori knowledge of the nature of potential contaminants. The ability to detect if a sample does not fit into the expected profile without recourse to multiple targeted analyses is a valuable tool for incident detection and forensic applications

  13. Carbon isotope (δ13C) excursions suggest times of major methane release during the last 14 ka in Fram Strait, the deep-water gateway to the Arctic

    Science.gov (United States)

    Consolaro, C.; Rasmussen, T. L.; Panieri, G.; Mienert, J.; Bünz, S.; Sztybor, K.

    2014-10-01

    We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (∼80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dating reveals a detailed chronology for the last 14 ka BP. The δ13C record measured on the benthic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values, as low as -4.37‰ in the Bølling-Allerød interstadials and as low as -3.41‰ in the early Holocene. After cleaning procedure designed to remove all authigenic carbonate coatings on benthic foraminiferal tests, the 13C values are still negative (as low as -2.75‰). We have interpreted these negative carbon isotope excursions (CIEs) to record past methane release events, resulting from the incorporation of 13C-depleted carbon from methane emissions into the benthic foraminiferal shells. The CIEs during the Bølling-Allerød interstadials and the early Holocene relate to periods of ocean warming, sea level rise and increased concentrations of methane (CH4) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

  14. Carbon isotope (δ13C excursions suggest times of major methane release during the last 14 ka in Fram Strait, the deep-water gateway to the Arctic

    Directory of Open Access Journals (Sweden)

    C. Consolaro

    2014-10-01

    Full Text Available We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (∼80° N in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dating reveals a detailed chronology for the last 14 ka BP. The δ13C record measured on the benthic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values, as low as −4.37‰ in the Bølling–Allerød interstadials and as low as −3.41‰ in the early Holocene. After cleaning procedure designed to remove all authigenic carbonate coatings on benthic foraminiferal tests, the 13C values are still negative (as low as −2.75‰. We have interpreted these negative carbon isotope excursions (CIEs to record past methane release events, resulting from the incorporation of 13C-depleted carbon from methane emissions into the benthic foraminiferal shells. The CIEs during the Bølling–Allerød interstadials and the early Holocene relate to periods of ocean warming, sea level rise and increased concentrations of methane (CH4 in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

  15. Oxygène-18, carbone-13, carbone-14 et diatomées dans les quatre carottes du lac Huynamarca (Bolivie) : premiers résultats

    OpenAIRE

    Wirrmann, Denis; Servant Vildary, Simone; Fontes, J.C.

    1982-01-01

    L'étude de géochimie isotopique des carbonates coquilliers de quatre carottes du lac Huynamarca (Bolivie), ainsi que les datations au carbone-14 de quelques échantillons montrent qu'au cours des dix derniers millénaires le bilan hydrologique du lac Titicaca a considérablement varié. Une phase sèche, située entre 3650 et 5325 ans B.P. se traduit par une baisse du niveau du lac d'au moins dix mètres par rapport à l'actuel, avec comme corrolaire l'augmentation de la teneur en sels dissous dans l...

  16. Engineering Studies of a Pilot Plant for Laser Isotope Separation of CARBON-13 by Multiphoton Dissociation of Chlorodifluoromethane

    Science.gov (United States)

    Mehmetli, Bulent Ahmet

    Recent research in laser isotope separation by multiphoton dissociation (LISMPD) of ^{13 }C suggests that an LISMPD commercial process is more economical than the cryogenic CO distillation technology currently used to meet most of the world's ^ {13}C demand. In this dissertation, experimental studies of an engineering process for LISMPD of polyatomic molecules is examined. The experimental results have been obtained by MPD of chlorodifluoromethane (CF_2 HCl) to yield ^{13}C -enriched tetrafluoroethylene rm(C_2F _4). Emphasis is on research leading to the development of a practical chemical plant for the preparation of stable isotopes by this method. The experimental program has achieved the design, construction, and operation of a laboratory-scale ^{13}C separation apparatus and parametric dependences of enrichment factors and dissociated fractions. In this experiment, the reactant gas, industrial grade CF_2HCl, flows continuously along the axis of a stainless steel reaction cell. The beam of a commercial CO_2 TEA laser, delivering up to 3 J/pulse at a single wavelength, is focused into the cell to induce isotope-selective multiphoton dissociation. The ^{13}C-enriched reaction product, rm C_2F_4, is analyzed by mass spectroscopy for its isotopic content. Typical production rates of the setup are about 10 g/year ^{13}C at an enrichment of 15% or 1 g/year at an enrichment of 65%. The results of a detailed cost analysis, which takes into account different reaction conditions and laser types, showed that at production rates of 7,000 kg per year, the cost of ^{13}C can be as low as 4/g. This figure is about an order of magnitude less than the cost of ^13 C obtained by cryogenic distillation of CO. The design, construction, and operation of a CO _2 MOPA (Master Oscillator/ Power Amplifier) laser is proposed because a MOPA combines the advantages of favorable isotope separation reaction conditions of TEA lasers and the cheaper photons of cw discharges. Analytical

  17. A hypersaline microbial mat from the Pacific Atoll Kiritimati: insights into composition and carbon fixation using biomarker analyses and a 13C-labeling approach.

    Science.gov (United States)

    Bühring, S I; Smittenberg, R H; Sachse, D; Lipp, J S; Golubic, S; Sachs, J P; Hinrichs, K-U; Summons, R E

    2009-06-01

    Modern microbial mats are widely recognized as useful analogs for the study of biogeochemical processes relevant to paleoenvironmental reconstruction in the Precambrian. We combined microscopic observations and investigations of biomarker composition to investigate community structure and function in the upper layers of a thick phototrophic microbial mat system from a hypersaline lake on Kiritimati (Christmas Island) in the Northern Line Islands, Republic of Kiribati. In particular, an exploratory incubation experiment with (13)C-labeled bicarbonate was conducted to pinpoint biomarkers from organisms actively fixing carbon. A high relative abundance of the cyanobacterial taxa Aphanocapsa and Aphanothece was revealed by microscopic observation, and cyanobacterial fatty acids and hydrocarbons showed (13)C-uptake in the labeling experiment. Microscopic observations also revealed purple sulfur bacteria (PSB) in the deeper layers. A cyclic C(19:0) fatty acid and farnesol were attributed to this group that was also actively fixing carbon. Background isotopic values indicate Calvin-Benson cycle-based autotrophy for cycC(19:0) and farnesol-producing PSBs. Biomarkers from sulfate-reducing bacteria (SRB) in the top layer of the mat and their (13)C-uptake patterns indicated a close coupling between SRBs and cyanobacteria. Archaeol, possibly from methanogens, was detected in all layers and was especially abundant near the surface where it contained substantial amounts of (13)C-label. Intact glycosidic tetraether lipids detected in the deepest layer indicated other archaea. Large amounts of ornithine and betaine bearing intact polar lipids could be an indicator of a phosphate-limited ecosystem, where organisms that are able to substitute these for phospholipids may have a competitive advantage.

  18. Assessment of the specific absorption rate and calibration of decoupling parameters for proton decoupled carbon-13 MR spectroscopy at 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Moyoko [Biomedical Imaging Group, Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)]. E-mail: moyoko-saitou@aist.go.jp; Matsuda, Tsuyoshi [Imaging Application Tech. Center, GE Yokogawa Medical Systems Ltd., Tokyo (Japan); Tropp, James [General Electric Company, CA (United States); Inubushi, Toshiro [Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga (Japan); Nakai, Toshiharu [Biomedical Imaging Group, Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan) and Institute of Biomedical Research and Innovation, Kobe (Japan)]. E-mail: t-nakai@aist.go.jp

    2005-08-01

    A strategy for proton decoupled carbon-13 MR spectroscopy ({l_brace}{sup 1}H{r_brace}-{sup 13}C MRS) with a strong static magnetic field (3.0 T) in vivo was investigated. The proton decoupling improves the signal-to-noise ratio, however, the effect of the decoupling power on the human body, especially in strong magnetic fields, should be considered. In order to establish a technique for monitoring the metabolism of glucose in the liver using {l_brace}{sup 1}H{r_brace}-{sup 13}C MRS at 3.0 T, two phantom experiments were performed. To assess whether the decoupling energy conformed to SAR limits defined by the IEC, temperature rises inside an agar gel phantom were monitored during a {l_brace}{sup 1}H{r_brace}-{sup 13}C MRS experiment. Then, the decoupling conditions of a glucose solution phantom were systematically optimized with combinations of decoupling bandwidth and power. The reliability of this procedure was discussed in conjunction with IEC guidelines.

  19. A novel dimethyl sulfoxide/1,3-dioxolane based electrolyte for lithium/carbon fluorides batteries with a high discharge voltage plateau

    International Nuclear Information System (INIS)

    A novel dimethyl sulfoxide/1,3-dioxolane (DMSO/1,3-DO) based electrolyte is proposed for lithium/carbon fluorides (Li/CFx) batteries to enhance the discharge voltage plateau and energy density. Conductivities of the electrolyte of 1 mol L−1 LiBF4/DMSO+1,3-DO with different volume ratios are not identical, which have a maximum of 14.85 mS cm−1. From the tests of galvanostatic discharge, the discharge voltage plateau of the Li/CFx battery with an electrolyte of 1 mol L−1 LiBF4/DMSO+1,3-DO (5:5, v:v) can reach 2.69 V at 0.1 C, delivering a maximum discharge capacity of 831 mAh g−1 and the highest energy density of 2196 Wh kg−1. Compared to Li/CFx batteries with an electrolyte of 1 mol L−1 LiBF4/PC+DME (5:5, v:v), the energy density of Li/CFx batteries with an electrolyte of 1 mol L−1 LiBF4/DMSO+1,3-DO (5:5, v:v) has been improved more than 12%. With the help of XRD, SEM, TEM, EIS, FT-IR and GC-MS analysis, the results of this work suggest that DMSO/1,3-DO based electrolyte can significantly improve the discharge performance of Li/CFx batteries and keep a good electrochemical stability during discharge. The main reason for improvement of discharge performance is decreasing of both the overpotential of electrochemical polarization of CFx cathodes during discharge and the overpotential of ohmic polarization by increasing the ion conductivity of electrolyte

  20. Carbon Metabolism of Soil microorganisms at Low Temperatures: Position-Specific 13C Labeled Glucose Reveals the Story

    Science.gov (United States)

    Apostel, C.; Bore, E. K.; Halicki, S.; Kuzyakov, Y.; Dippold, M.

    2015-12-01

    Metabolic pathway activities at low temperature are not well understood, despite the fact that the processes are relevant for many soils globally and seasonally. To analyze soil metabolism at low temperature, isotopomeres of position-specifically 13C labeled glucose were applied at three temperature levels; +5, -5 -20 oC. In additon, one sterilization treatment with sodium azide at +5 oC was also performed. Soils were incubated for 1, 3 and 10 days while soil samples at -20 oC were additionally sampled after 30 days. The 13C from individual molecule position in respired CO2 was quantifed. Incorporation of 13C in bulk soil, extractable microbial biomass by chloroform fumigation extraction (CFE) and cell membranes of different microbial communities classified by 13C phospholipid fatty acid analysis (PLFA) was carried out. Our 13CO2 data showed a dominance of C-1 respiration at +5 °C for treatments with and without sodium azide, but total respiration for sodium azide inhibited treatments increased by 14%. In contrast, at -5 and -20 oC metabolic behavior showed intermingling of preferential respiration of the glucose C-4 and C-1 positions. Therefore, at +5 °C, pentose phosphate pathway activity is a dominant metabolic pathway used by microorganisms to metabolize glucose. The respiration increase due to NaN3 inhibition was attributed to endoenzymes released from dead organisms that are stabilized at the soil matrix and have access to suitable substrate and co-factors to permit their funtions. Our PLFA analysis showed that incorporation of glucose 13C was higher in Gram negative bacteria than other microbial groups as they are most competitive for LMWOS. Only a limited amount of microbial groups maintained their glucose utilizing activity at -5 and -20 °C and they strongly shifted towards a metabolization of glucose via both glycolysis and pentose phosphate pathways indicating both growth and cellular maintenance. This study revealed a remarkable microbial acitivity

  1. Probabilistic Approach to Determining Unbiased Random-coil Carbon-13 Chemical Shift Values from the Protein Chemical Shift Database

    International Nuclear Information System (INIS)

    We describe a probabilistic model for deriving, from the database of assigned chemical shifts, a set of random coil chemical shift values that are 'unbiased' insofar as contributions from detectable secondary structure have been minimized (RCCSu). We have used this approach to derive a set of RCCSu values for 13Cα and 13Cβ for 17 of the 20 standard amino acid residue types by taking advantage of the known opposite conformational dependence of these parameters. We present a second probabilistic approach that utilizes the maximum entropy principle to analyze the database of 13Cα and 13Cβ chemical shifts considered separately; this approach yielded a second set of random coil chemical shifts (RCCSmax-ent). Both new approaches analyze the chemical shift database without reference to known structure. Prior approaches have used either the chemical shifts of small peptides assumed to model the random coil state (RCCSpeptide) or statistical analysis of chemical shifts associated with structure not in helical or strand conformation (RCCSstruct-stat). We show that the RCCSmax-ent values are strikingly similar to published RCCSpeptide and RCCSstruct-stat values. By contrast, the RCCSu values differ significantly from both published types of random coil chemical shift values. The differences (RCCSpeptide-RCCSu) for individual residue types show a correlation with known intrinsic conformational propensities. These results suggest that random coil chemical shift values from both prior approaches are biased by conformational preferences. RCCSu values appear to be consistent with the current concept of the 'random coil' as the state in which the geometry of the polypeptide ensemble samples the allowed region of (φ,ψ)-space in the absence of any dominant stabilizing interactions and thus represent an improved basis for the detection of secondary structure. Coupled with the growing database of chemical shifts, this probabilistic approach makes it possible to refine

  2. Determination of the δ15N and δ13C of total nitrogen and carbon in solids; RSIL lab code 1832

    Science.gov (United States)

    Revesz, Kinga; Qi, Haiping; Coplan, Tyler B.

    2006-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1832 is to determine the δ(15N/14N), abbreviated as δ15N, and the δ(13C/12C), abbreviated as δ13C, of total nitrogen and carbon in a solid sample. A Carlo Erba NC 2500 elemental analyzer (EA) is used to convert total nitrogen and carbon in a solid sample into N2 and CO2 gas. The EA is connected to a continuous flow isotope-ratio mass spectrometer (CF-IRMS), which determines the relative difference in stable nitrogen isotope-amount ratio (15N/14N) of the product N2 gas and the relative difference in stable carbon isotope-amount ratio (13C/12C) of the product CO2 gas. The combustion is quantitative; no isotopic fractionation is involved. Samples are placed in tin capsules and loaded into a Costech Zero Blank Autosampler on the EA. Under computer control, samples then are dropped into a heated reaction tube that contains an oxidant, where combustion takes place in a helium atmosphere containing an excess of oxygen gas. Combustion products are transported by a helium carrier through a reduction furnace to remove excess oxygen and to convert all nitrous oxides into N2 and through a drying tube to remove water. The gas-phase products, mainly CO2 and N2, are separated by a gas chromatograph. The gas is then introduced into the IRMS through a Finnigan MAT (now Thermo Scientific) ConFlo II interface. The Finnigan MAT ConFlo II interface is used for introducing not only sample into the IRMS but also N2 and CO2 reference gases and helium for sample dilution. The flash combustion is quantitative; no isotopic fractionation is involved. The IRMS is a Thermo Scientific Delta V CF-IRMS. It has a universal triple collector, two wide cups with a narrow cup in the middle; it is capable of measuring mass/charge (m/z) 28, 29, 30 or with a magnet current change 44, 45, 46, simultaneously. The ion beams from these m/z values are as follows: m/z 28 = N2 = 14N/14N; m/z 29 = N2 = 14N/15N primarily; m/z 30 = NO = 14N/16O

  3. δ15N, δ13C and radiocarbon in dissolved organic carbon as indicators of environmental change

    International Nuclear Information System (INIS)

    Decomposition, humification, and stabilization of soil organic matter are closely related to the dynamics of dissolved organic matter. Enhanced peat decomposition results in increasing aromatic structures and polycondensation of dissolved organic molecules. Although recent studies support the concept that DOM can serve as an indicator for processes driven by changing environmental processes in soils affecting the C and N cycle (like decomposition and humification) and also permit insight in former conditions some 1000 years ago, it is unknown whether dissolved organic carbon (DOC) and nitrogen (DON) have an equal response to these processes. (author)

  4. 土壤跳虫在碳循环中的作用--13C示踪研究%Role of Collembola in Carbon Transformation--A13C-labelling Study

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    很容易通过呼吸作用释放回到大气,尤其在初期,绝大部分排放的 CO2都源自新 C。土壤跳虫在食物网中的作用明显,对土壤微生物具有显著的调控作用。%Terrestrial carbon cycle is one of the key issues in the world. Soil fauna play essential roles in soil ecosystem which is the largest terrestrial carbon sink. However, both the contributions of soil fauna to carbon transformation and the underlying mechanisms are still unclear. The isotope technology provided an useful method to quantify the key processes in soil food web and material cycling. In this study,13C-labeled leaf litter was used to investigate the effect of the Collembola (Folsomia Candida) on carbon transformation in laboratory microcosms. Three treatments were set up: (1) soil (control, S), (2) soil and labeled litter (SL), and (3) soil, labeled litter and Collembola (SLC). Each treatment has four replicates. These microcosms were destructively sampled on day 7, 21, 63 after the experiment initiation. The results showed that litter-derived C was incorporated into soil biota rapidly. The originalδ13C values of Collembola was -9.91‰±0.08‰, and it reached 522.70‰ after 7 days of incubation indicating that Collembola could efficiently assimilate this newly introduced litter-derived C. Similarly, theδ13C values in PLFAs increased significantly, especially at the initial experimental stage. In addition, the presence of Collembola significantly promoted the PLFAsδ13C suggesting that Collembola could accelerate the microbial assimilation of litter carbon. Unexpectedly, treatment SLC exhibited significantly lowerδ13C values than treatment SL. This may indicate that the presence of Collembola stimulated the release of newly metabolized litter C. Both of the treatments stimulated CO2 flux significantly. By C isotope analysis, over 85% of the mineralized C derived from litter at the initiation state (21 days), demonstrating that new C from fresh litter

  5. Carbon-13 natural abundance signatures of long-chain fatty acids to determinate sediment origin: A case study in northeast Austria

    Science.gov (United States)

    Mabit, Lionel; Gibbs, Max; Meusburger, Katrin; Toloza, Arsenio; Resch, Christian; Klik, Andreas; Swales, Andrew; Alewell, Christine

    2016-04-01

    - Several recently published information from scientific research have highlighted that compound-specific stable isotope (CSSI) signatures of fatty acids (FAs) based on the measurement of carbon-13 natural abundance signatures showed great promises to identify sediment origin. The authors have used this innovative isotopic approach to investigate the sources of sediment in a three hectares Austrian sub-watershed (i.e. Mistelbach). Through a previous study using the Cs-137 technique, Mabit et al. (Geoderma, 2009) reported a local maximum sedimentation rate reaching 20 to 50 t/ha/yr in the lowest part of this watershed. However, this study did not identify the sources. Subsequently, the deposited sediment at its outlet (i.e. the sediment mixture) and representative soil samples from the four main agricultural fields - expected to be the source soils - of the site were investigated. The bulk delta carbon-13 of the samples and two long-chain FAs (i.e. C22:0 and C24:0) allowed the best statistical discrimination. Using two different mixing models (i.e. IsoSource and CSSIAR v1.00) and the organic carbon content of the soil sources and sediment mixture, the contribution of each source has been established. Results suggested that the grassed waterway contributed to at least 50% of the sediment deposited at the watershed outlet. This study, that will require further validation, highlights that CSSI and Cs-137 techniques are complementary as fingerprints and tracers for establishing land sediment redistribution and could provide meaningful information for optimized decision-making by land managers.

  6. Assessment of the effects of dobutamine on myocardial blood flow and oxidative metabolism in normal human subjects using nitrogen-13 ammonia and carbon-11 acetate.

    Science.gov (United States)

    Krivokapich, J; Huang, S C; Schelbert, H R

    1993-06-01

    The dual purposes of this study with positron emission tomography were to measure the effects of dobutamine on myocardial blood flow and oxidative metabolism, and to compare carbon-11 (C-11) acetate versus nitrogen-13 (N-13) ammonia in quantitating flow in normal subjects. Flow was quantitated with N-13 ammonia at rest and at peak dobutamine infusion (40 micrograms/kg/min) in 21 subjects. In 11 subjects, oxidative metabolism was also estimated at rest and peak dobutamine infusion using the clearance rate of C-11 acetate, k mono (min-1). A 2-compartment kinetic model was applied to the early phase of the C-11 acetate data to estimate flow. The rest and peak dobutamine rate-pressure products were 7,318 +/- 1,102 and 19,937 +/- 3,964 beats/min/mm Hg, respectively, and correlated well (r = 0.77) with rest and peak dobutamine flows of 0.77 +/- 0.14 and 2.25 ml/min/g determined using N-13 ammonia as a flow tracer. Rest and dobutamine flows estimated with C-11 acetate were highly correlated with those determined with N-13 ammonia (r = 0.92). k mono increased from 0.05 +/- 0.01 to 0.18 +/- 0.02 min-1, and correlated highly with the increase in flows (r = 0.91) and rate-pressure products (r = 0.94). Thus, the increase in cardiac demand associated with dobutamine is highly correlated with an increase in supply and oxidative metabolism. C-11 acetate is a unique tracer that can be used to image both flow and metabolism simultaneously. PMID:8498380

  7. Losses of soil organic carbon by converting tropical forest to plantations: Assessment of erosion and decomposition by new δ13C approach

    Science.gov (United States)

    Guillaume, Thomas; Muhammad, Damris; Kuzyakov, Yakov

    2015-04-01

    Indonesia lost more tropical forest than all of Brazil in 2012, mainly driven by the rubber, oil palm and timber industries. Nonetheless, the effects of converting forest to oil palm and rubber plantations on soil organic carbon (SOC) stocks remain unclear. We analyzed SOC losses after lowland rainforest conversion to oil palm, intensive rubber and extensive rubber plantations in Jambi province on Sumatra Island. We developed and applied a new δ13C based approach to assess and separate two processes: 1) erosion and 2) decomposition. Carbon contents in the Ah horizon under oil palm and rubber plantations were strongly reduced: up to 70% and 62%, respectively. The decrease was lower under extensive rubber plantations (41%). The C content in the subsoil was similar in the forest and the plantations. We therefore assumed that a shift to higher δ13C values in the subsoil of the plantations corresponds to the losses of the upper soil layer by erosion. Erosion was estimated by comparing the δ13C profiles in the undisturbed soils under forest with the disturbed soils under plantations. The estimated erosion was the strongest in oil palm (35±8 cm) and rubber (33±10 cm) plantations. The 13C enrichment of SOC used as a proxy of its turnover indicates a decrease of SOC decomposition rate in the Ah horizon under oil palm plantations after forest conversion. SOC availability, measured by microbial respiration rate and Fourier Transformed Infrared Spectroscopy, was lower under oil palm plantations. Despite similar trends in C losses and erosion in intensive plantations, our results indicate that microorganisms in oil palm plantations mineralized mainly the old C stabilized prior to conversion, whereas microorganisms under rubber plantations mineralized the fresh C from the litter, leaving the old C pool mainly untouched. Based on the lack of C input from litter, we expect further losses of SOC under oil palm plantations, which therefore are a less sustainable land

  8. Carbonation of C–S–H and C–A–S–H samples studied by {sup 13}C, {sup 27}Al and {sup 29}Si MAS NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sevelsted, Tine F.; Skibsted, Jørgen, E-mail: jskib@chem.au.dk

    2015-05-15

    Synthesized calcium silicate hydrate (C–S–H) samples with Ca/Si ratios of 0.66, 1.0, and 1.5 have been exposed to atmospheric CO{sub 2} at room temperature and high relative humidity and studied after one to 12 weeks. {sup 29}Si NMR reveals that the decomposition of C–S–H caused by carbonation involves two steps and that the decomposition rate decreases with increasing Ca/Si ratio. The first step is a gradual decalcification of the C–S–H where calcium is removed from the interlayer and defect sites in the silicate chains until Ca/Si = 0.67 is reached, ideally corresponding to infinite silicate chains. In the seconds step, calcium from the principal layers is consumed, resulting in the final decomposition of the C–S–H and the formation of an amorphous silica phase composed of Q{sup 3} and Q{sup 4} silicate tetrahedra. The amount of solid carbonates and of carbonate ions in a hydrous environment increases with increasing Ca/Si ratio for the C–S–H, as shown by {sup 13}C NMR. For C–A–S–H samples with Ca/Si = 1.0 and 1.5, {sup 27}Al NMR demonstrates that all aluminium sites associated with the C–S–H are consumed during the carbonation reactions and incorporated mainly as tetrahedral Al(–OSi){sub 4} units in the amorphous silica phase. A small amount of penta-coordinated Al sites has also been identified in the silica phase.

  9. Studies of palaeovegetation changes in the Central Amazon by carbon isotopes (12C, 13C, 14C) of soil organic matter

    International Nuclear Information System (INIS)

    The paper presents carbon isotope data δ13C and 14C on soil organic matter collected along an ecosystem transect in southern Amazon state, north-central Amazon region, that includes three distinct vegetation communities: savannah (Campos de Humaita), a savannah-forest transition and forest (Manaus). The study sites are located along road BR 319. Botanical identification and 13C analysis of modern vegetation in the savannah and forest sites indicate that most of the vegetation is C3 plants, although a few C4 plants are present at Campos de Humaita. The 13C and 14C data for soil organic matter in the Humaita region show that significant vegetation changes have occurred in the past, probably associated with climatic changes. During the early Holocene, forest vegetation extended throughout the study region, including areas occupied today by savannah vegetation. Savannah vegetation expanded at least 2 km into the modern forest ecotone during the middle Holocene, suggesting drier conditions. The last approximately 1000 years appear to indicate a recent expansion of forest vegetation, reflecting a return to a more moist climate. The study illustrates that the transition area between forest and savannah vegetation is quite sensitive to climatic changes, and this region should be the focus of more extensive research related to past climate and vegetation dynamics in the Amazon region. (author)

  10. A report on the inter comparison of isotopic analyses by mass spectrometry for the laser enrichment of carbon-13

    International Nuclear Information System (INIS)

    A method has been standardized for the mass spectral analysis of (13C/12C) ratio in the isotopically enriched C2F4 photoproduct obtained by the CO2 laser photolysis of natural CF2HCI sample. For improving the quality of the spectra as well as enchancing the detection level of the product at very low concentrations, a pre-concentration technique has been developed by gas chromatography. Inter comparison of the results for analyses carried out with two different mass spectrometers, viz., a commercial instrument available at the Land PT Division and an indigenously built one by MS and ES, BARC showed a very good agreement. (author)

  11. Carbon transfer, partitioning and residence time in the plant-soil system: a comparison of two 13CO2 labelling techniques

    Science.gov (United States)

    Studer, M. S.; Siegwolf, R. T. W.; Abiven, S.

    2014-03-01

    Various 13CO2 labelling approaches exist to trace carbon (C) dynamics in plant-soil systems. However, it is not clear if the different approaches yield the same results. Moreover, there is no consistent way of data analysis to date. In this study we compare with the same experimental setup the two main techniques: pulse and continuous labelling. We evaluate how these techniques perform to estimate the C transfer time, the C partitioning along time and the C residence time in different plant-soil compartments. We used identical plant-soil systems (Populus deltoides × nigra, Cambisol soil) to compare the pulse labelling approach (exposure to 99 atom % 13CO2 for three hours, traced for eight days) with a continuous labelling (exposure to 10 atom % 13CO2, traced for 14 days). The experiments were conducted in climate chambers under controlled environmental conditions. Before label addition and at four successive sampling dates, the plant-soil systems were destructively harvested, separated into leaves, petioles, stems, cuttings, roots and soil and soil microbial biomass was extracted. The soil CO2 efflux was sampled throughout the experiment. To model the C dynamics we used an exponential function to describe the 13C signal decline after pulse labelling. For the evaluation of the 13C distribution during the continuous labelling we applied a logistic function. Pulse labelling is best suited to assess the minimum C transfer time from the leaves to other compartments, while continuous labelling can be used to estimate the mean transfer time through a compartment, including short-term storage pools. The C partitioning between the plant-soil compartments obtained was similar for both techniques, but the time of sampling had a large effect: shortly after labelling the allocation into leaves was overestimated and the soil 13CO2 efflux underestimated. The results of belowground C partitioning were consistent for the two techniques only after eight days of labelling, when the

  12. Dating Cactus: Annual and Sub-annual Variations of Oxygen-18, Carbon-13 and Radiocarbon in Spines of a Columnar Cactus, Carnegiea gigantea.

    Science.gov (United States)

    Dettman, D. L.; English, N. B.; Sandquist, D. R.; Williams, D. G.

    2006-12-01

    We measured δ18O, δ13C and F14C of spines from a long-lived columnar cactus, Carnegiea gigantea (saguaro), to resolve a record of plant physiological responses to annual and sub-annual climate variation in the eastern Sonoran Desert. Spines grow from the apex of the cactus and are arranged serially along the side of the cactus oldest at the base, youngest at the apex. To establish the age of the spine series, we measured F14C of spines collected at 8 different heights from the apex (3.77 m) to the base of a naturally occurring saguaro. These spines yielded fractions of modern carbon (F14C) from 0.9679 and 1.5537, indicating the presence of carbon in spine tissue derived from atmospheric nuclear testing. We used the F14C of spine tissue to calculate the year of spine emergence for each of the 11 spines, assuming minimal re-allocation of stored carbon to growing spines. At the same 8 heights, we interpolated the date of spine emergence from observed height measurements made between 1964 and 2002. A very strong positive correlation (linear regression, r2 = 0.99, P < 0.0001) between the F14C age of spines and ages determined from direct height measurements was observed, with a two year offset suggesting incorporation of carbon from fossil fuel combustion sources in the Tucson basin. Additionally, spine tips from 97 spines collected serially from the top half of the same saguaro (between 1.77 and 3.50 m) and representing ~15 years of growth, yielded δ18O variations in spine bulk organic material from 38° to 50° (VSMOW) and in δ13C from ° to 11.5° (VPDB). The δ18O and δ13C values were positively correlated over the entire record (linear regression, r2 = 0.22, P < 0.0001). These variations occurred at or near an annual frequency. The most negative δ18O and δ13C values in bulk spine organic material from the naturally occurring cactus were observed in spines grown shortly following the 1983 and 1993 strong El Niño winter precipitation events in Tucson

  13. Changing Rule of Carbon-Enriched Zone and Diffusion Behavior of Carbon in Aging 0Cr6Mn13Ni10MoTi/1Cr5Mo Dissimilar Welded Joints

    Institute of Scientific and Technical Information of China (English)

    Zheng LIU; Ligang WANG; Lai WANG

    2004-01-01

    The microstructures, the changing rule of carbon-enriched zone, the diffusion behaviors of elements C and Cr, and the carbide type of 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints after aging at 500℃ for various times and after long-term service in technical practice were investigated by using the optical microscopy, electron probe microanalysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that in aging 0Cr6Mn13Ni10MoTi/1Cr5Mo dissimilar welded joints, the main carbides are M3C and a few carbides are M7C3 and M23C6. The M3C carbide decomposition and dissolution with increasing aging time or aging temperature and the anti-diffusion of C and Cr cause the decrease and disappearance of the carbon-enriched zone. The results are different from those of the A302/1Cr5Mo dissimilar welded joints in previous studies.

  14. Study of Target Fragmentation in the Interaction of 86 MeV/A $^{12}$Carbon with Tantalum, Bismuth and Uranium

    CERN Multimedia

    2002-01-01

    Using radiochemical techniques we will ; a)~~measure the target fragment mass and charge distributions from the interaction of 86~MeV/A |1|2C with Ta, Bi and U; ; b)~~measure the target fragment forward momentum and average kinetic energy using the thick target-thick catcher technique for the above reactions; and ; c)~~measure the target fragment angular and differential energy distributions using thin target-thin catcher techniques for the reactions with Ta and U. \\\\ \\\\ These measurements should allow us to better characterize the transition between low energy and realistic heavy ion reaction mechanisms.

  15. Structure determination of a 2''-O(α-D-glucopyranose) isomaltotriose by proton and carbon-13 NMR

    International Nuclear Information System (INIS)

    The glucosyltransferases from Leuconostoc mesenteroides are known to catalyze the transfer of the D-glucosyl group of sucrose onto sugars, commonly named acceptors. We investigated in the present work the transfer of the glucose moiety of sucrose onto isomaltose acceptor catalyzed by the glucosyltransferases from Leuconostoc mesenteroides. Several oligosaccharides were produced, isolated, fractionated by HPLC and characterized. The primary structure of the tetrasaccharide has been determined as that of 2'' -O-(α-D-glucopyranose) isomaltotriose by n.m.r. spectroscopy, using homo-and heteronuclear, shift correlated, two dimensional and n.o.e. difference experiments. This chemical structure was corrobored by 13C spin lattice relaxation time measurements (T1) indicating that internal units B and C are notably less flexible than A and D termini units, C being the less mobile. (authors). 18 refs., 3 figs., 3 tabs

  16. Dosimetric characterization and application of an imaging beam line with a carbon electron target for megavoltage cone beam computed tomography.

    Science.gov (United States)

    Flynn, Ryan T; Hartmann, Julia; Bani-Hashemi, Ali; Nixon, Earl; Alfredo, R; Siochi, C; Pennington, Edward C; Bayouth, John E

    2009-06-01

    Imaging dose from megavoltage cone beam computed tomography (MVCBCT) can be significantly reduced without loss of image quality by using an imaging beam line (IBL), with no flattening filter and a carbon, rather than tungsten, electron target. The IBL produces a greater keV-range x-ray fluence than the treatment beam line (TBL), which results in a more optimal detector response. The IBL imaging dose is not necessarily negligible, however. In this work an IBL was dosimetrically modeled with the Philips Pinnacle3 treatment planning system (TPS), verified experimentally, and applied to clinical cases. The IBL acquisition dose for a 200 degrees gantry rotation was verified in a customized acrylic cylindrical phantom at multiple imaging field sizes with 196 ion chamber measurements. Agreement between the measured and calculated IBL dose was quantified with the 3D gamma index. Representative IBL and TBL imaging dose distributions were calculated for head and neck and prostate patients and included in treatment plans using the imaging dose incorporation (IDI) method. Surface dose was measured for the TBL and IBL for four head and neck cancer patients with MOSFETs. The IBL model, when compared to the percentage depth dose and profile measurements, had 97% passing gamma indices for dosimetric and distance acceptance criteria of 3%, 3 mm, and 100% passed for 5.2%, 5.2 mm. For the ion chamber measurements of phantom image acquisition dose, the IBL model had 93% passing gamma indices for acceptance criteria of 3%, 3 mm, and 100% passed for 4%, 4 mm. Differences between the IBL- and TBL-based IMRT treatment plans created with the IDI method were dosimetrically insignificant for both the prostate and head and neck cases. For IBL and TBL beams with monitor unit values that would result in the delivery of the same dose to the depth of maximum dose under standard calibration conditions, the IBL imaging surface dose was higher than the TBL imaging surface dose by an average of 18

  17. Thick-target neutron, gamma-ray, and radionuclide production for protons below 12 MeV on nickel and carbon beam-stops

    Energy Technology Data Exchange (ETDEWEB)

    Chadwick, M.B.; Young, P.G.; Wilson, W.B.

    1998-03-01

    Nuclear model calculations using the GNASH code are described for protons below 12 MeV incident on nickel and carbon isotopes, for beam stop design in the Los Alamos Accelerator Production of Tritium Low Energy Demonstration Accelerator (LEDA) project. The GNASH calculations apply Hauser-Feshbach and preequilibrium reaction theories and can make use of pre-calculated direct reaction cross sections to low-lying residual nucleus states. From calculated thin target cross sections, thick target 6.7 MeV and 12 MeV proton-induced production of neutrons, gamma rays, and radionuclides are determined. Emission spectra of the secondary neutrons and gamma rays are also determined. The model calculations are validated through comparisons with experimental thin- and thick-target measurements. The results of this work are being utilized as source terms in MCNP analyses for LEDA.

  18. Carbon flux analysis by 13C nuclear magnetic resonance to determine the effect of CO2 on anaerobic succinate production by Corynebacterium glutamicum.

    Science.gov (United States)

    Radoš, Dušica; Turner, David L; Fonseca, Luís L; Carvalho, Ana Lúcia; Blombach, Bastian; Eikmanns, Bernhard J; Neves, Ana Rute; Santos, Helena

    2014-05-01

    Wild-type Corynebacterium glutamicum produces a mixture of lactic, succinic, and acetic acids from glucose under oxygen deprivation. We investigated the effect of CO2 on the production of organic acids in a two-stage process: cells were grown aerobically in glucose, and subsequently, organic acid production by nongrowing cells was studied under anaerobic conditions. The presence of CO2 caused up to a 3-fold increase in the succinate yield (1 mol per mol of glucose) and about 2-fold increase in acetate, both at the expense of l-lactate production; moreover, dihydroxyacetone formation was abolished. The redistribution of carbon fluxes in response to CO2 was estimated by using (13)C-labeled glucose and (13)C nuclear magnetic resonance (NMR) analysis of the labeling patterns in end products. The flux analysis showed that 97% of succinate was produced via the reductive part of the tricarboxylic acid cycle, with the low activity of the oxidative branch being sufficient to provide the reducing equivalents needed for the redox balance. The flux via the pentose phosphate pathway was low (~5%) regardless of the presence or absence of CO2. Moreover, there was significant channeling of carbon to storage compounds (glycogen and trehalose) and concomitant catabolism of these reserves. The intracellular and extracellular pools of lactate and succinate were measured by in vivo NMR, and the stoichiometry (H(+):organic acid) of the respective exporters was calculated. This study shows that it is feasible to take advantage of natural cellular regulation mechanisms to obtain high yields of succinate with C. glutamicum without genetic manipulation. PMID:24610842

  19. Bringing hope to marginal and harsh environments: The use of carbon-13 isotope discrimination technique to evaluate and select food crops adapted to water and salt stress environments

    International Nuclear Information System (INIS)

    Many countries have weather patterns and soil characteristics that place major constraints on food production systems over large tracts of land. Thus a major challenge for making better use of these marginal lands is not only to select appropriate crops but also to evaluate and optimize their adaptability and crop productivity under extreme climatic conditions (high temperatures and low rainfall) or where soils suffer from salinity, acidity or low plant nutrient status. The carbon isotope discrimination technique (using the ratios of different carbon isotopes [12C/13C] in plants) commonly referred to as CID, has been proposed as a possible selection criterion for greater water use efficiency in breeding programmes for water limited and salt stress environments because it provides an integrative assessment of genotypic variation in leaf transpiration efficiency. Although the relationship between CID and water and/or salt stress have been well studied and documented for many crop plants, few studies have looked at the combined effects of salt, water and nutrient stresses on the potential use of this technique to select and evaluate crop plants adapted to harsh environments

  20. Traceability of animal byproducts in quail (Coturnix coturnix japonica tissues using carbon (13C/12C and nitrogen (15N/14N stable isotopes

    Directory of Open Access Journals (Sweden)

    C Móri

    2007-12-01

    Full Text Available Consistent information on meat products consumed by the public is essential. The technique of stable isotopes is a powerful tool to recover consumers' confidence, as it allows the detection of animal byproduct residues in poultry meat, particularly in quail meat. This study aimed at checking the presence of poultry byproduct mixtures in quail diets by applying the technique of carbon (13C/12C and nitrogen (15N/14N stable isotopes in quail breast muscle, keel, and tibia. Sixty four one-day-old male quails were obtained from a commercial farm. Birds were housed in an experimental house from one to 42 days of age, and were randomly distributed into 8 experimental treatments, and fed diets containing poultry offal meal (POM, bovine meat and bone meal (MBM or poultry feather meal (PFM, or their mixtures. Four birds per treatment were slaughtered at 42 days of age, and breast (Pectoralis major, keel, and tibia were collected for analyses. The inclusion of animal byproducts in quail diets was detected by 13C e 15N analyses in the tissues of the birds; however, it was not possible to specify which byproducts were used. It was concluded that quail meat can be certified by the technique of stable isotopes.

  1. Pan-Arctic concentrations of mercury and stable isotope ratios of carbon (δ(13)C) and nitrogen (δ(15)N) in marine zooplankton.

    Science.gov (United States)

    Pomerleau, Corinne; Stern, Gary A; Pućko, Monika; Foster, Karen L; Macdonald, Robie W; Fortier, Louis

    2016-05-01

    Zooplankton play a central role in marine food webs, dictating the quantity and quality of energy available to upper trophic levels. They act as "keystone" species in transfer of mercury (Hg) up through the marine food chain. Here, we present the first Pan-Arctic overview of total and monomethylmercury concentrations (THg and MMHg) and stable isotope ratios of carbon (δ(13)C) and nitrogen (δ(15)N) in selected zooplankton species by assembling data collected between 1998 and 2012 from six arctic regions (Laptev Sea, Chukchi Sea, southeastern Beaufort Sea, Canadian Arctic Archipelago, Hudson Bay and northern Baffin Bay). MMHg concentrations in Calanus spp., Themisto spp. and Paraeuchaeta spp. were found to increase with higher δ(15)N and lower δ(13)C. The southern Beaufort Sea exhibited both the highest THg and MMHg concentrations. Biomagnification of MMHg between Calanus spp. and two of its known predators, Themisto spp. and Paraeuchaeta spp., was greatest in the southern Beaufort Sea. Our results show large geographical variations in Hg concentrations and isotopic signatures for individual species related to regional ecosystem features, such as varying water masses and freshwater inputs, and highlight the increased exposure to Hg in the marine food chain of the southern Beaufort Sea. PMID:26874765

  2. Priming of soil carbon decomposition in two inner Mongolia grassland soils following sheep dung addition: A study using13C natural abundance approach

    DEFF Research Database (Denmark)

    Ma, Xiuzhi; Ambus, Per; Wang, Shiping;

    2013-01-01

    To investigate the effect of sheep dung on soil carbon (C) sequestration, a 152 days incubation experiment was conducted with soils from two different Inner Mongolian grasslands, i.e. a Leymus chinensis dominated grassland representing the climax community (2.1% organic matter content...... with the two grassland soils and incubated under controlled conditions for analysis of 13C-CO2 emissions. Soil samples were taken at days 17, 43, 86, 127 and 152 after sheep dung addition to detect the δ 13C signal in soil and dung components. Analysis revealed that 16.9% and 16.6% of the sheep dung C had...... decomposed, of which 3.5% and 2.8% was sequestrated in the soils of L. chinensis and A. frigida grasslands, respectively, while the remaining decomposed sheep dung was emitted as CO 2. The cumulative amounts of C respired from dung treated soils during 152 days were 7-8 times higher than in the un...

  3. Carbon-rich presolar grains from massive stars. Subsolar 12C/13C and 14N/15N ratios and the mystery of 15N

    CERN Document Server

    Pignatari, M; Hoppe, P; Jordan, C J; Gibson, B K; Trappitsch, R; Herwig, F; Fryer, C; Hirschi, R; Timmes, F X

    2015-01-01

    Carbon-rich grains with isotopic anomalies compared to the Sun are found in primitive meteorites. They were made by stars, and carry the original stellar nucleosynthesis signature. Silicon carbide grains of Type X and C, and low-density graphites condensed in the ejecta of core-collapse supernovae. We present a new set of models for the explosive He shell and compare them with the grains showing 12C/13C and 14N/15N ratios lower than solar. In the stellar progenitor H was ingested into the He shell and not fully destroyed before the explosion. Different explosion energies and H concentrations are considered. If the SN shock hits the He-shell region with some H still present, the models can reproduce the C and N isotopic signatures in C-rich grains. Hot-CNO cycle isotopic signatures are obtained, including a large production of 13C and 15N. The short-lived radionuclides 22Na and 26Al are increased by orders of magnitude. The production of radiogenic 22Ne from the decay of 22Na in the He shell might solve the pu...

  4. Carbon and silver nanoparticles in the fight against the filariasis vector Culex quinquefasciatus: genotoxicity and impact on behavioral traits of non-target aquatic organisms.

    Science.gov (United States)

    Murugan, Kadarkarai; Nataraj, Devaraj; Madhiyazhagan, Pari; Sujitha, Vasu; Chandramohan, Balamurugan; Panneerselvam, Chellasamy; Dinesh, Devakumar; Chandirasekar, Ramachandran; Kovendan, Kalimuthu; Suresh, Udaiyan; Subramaniam, Jayapal; Paulpandi, Manickam; Vadivalagan, Chithravel; Rajaganesh, Rajapandian; Wei, Hui; Syuhei, Ban; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Canale, Angelo; Benelli, Giovanni

    2016-03-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. The Culex genus, with special reference to Culex quinquefasciatus, comprises the most common vectors of filariasis across urban and semi-urban areas of Asia. In recent years, important efforts have been conducted to propose green-synthesized nanoparticles as a valuable alternative to synthetic insecticides. However, the mosquitocidal potential of carbon nanoparticles has been scarcely investigated. In this study, the larvicidal and pupicidal activity of carbon nanoparticle (CNP) and silver nanoparticle (AgNP) was tested against Cx. quinquefasciatus. UV-Vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and Raman analysis confirmed the rapid and cheap synthesis of carbon and silver nanoparticles. In laboratory assays, LC50 (lethal concentration that kills 50 % of the exposed organisms) values ranged from 8.752 ppm (first-instar larvae) to 18.676 ppm (pupae) for silver nanoparticles and from 6.373 ppm (first-instar larvae) to 14.849 ppm (pupae) for carbon nanoparticles. The predation efficiency of the water bug Lethocerus indicus after a single treatment with low doses of silver and carbon nanoparticles was not reduced. Moderate evidence of genotoxic effects induced by exposure to carbon nanoparticles was found on non-target goldfish, Carassius auratus. Lastly, the plant extract used for silver nanosynthesis was tested for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Overall, our results pointed out that AgNP and CNP can be a candidate for effective tools to reduce larval and pupal populations of filariasis vectors, with reduced genotoxicity and impact on behavioral traits of other aquatic organisms sharing the same ecological

  5. Measurement of analyzing powers of π+ and π- produced on a hydrogen and a carbon target with a 22-GeV/c incident polarized proton beam

    International Nuclear Information System (INIS)

    The analyzing powers of π+ and π- were measured using an incident 22-GeV/c transversely polarized proton beam at the Brookhaven Alternating Gradient Synchrotron. A magnetic spectrometer measured π± inclusive asymmetries on a hydrogen and a carbon target. An elastic polarimeter with a CH2 target measured pp elastic-scattering asymmetries to determine the beam polarization using published data for the pp elastic analyzing power. Using the beam polarization determined from the elastic polarimeter and asymmetries from the inclusive spectrometer, analyzing powers AN for π± were determined in the xF and pT ranges (0.45-0.8) and (0.3-1.2 GeV/c), respectively. The analyzing power results are similar in both sign and character to other measurements at 200 and 11.7 GeV/c, confirming the expectation that high-energy pion inclusive analyzing powers remain large and relatively energy independent. This suggests that pion inclusive polarimetry may be a suitable method for measuring future beam polarizations at BNL RHIC or DESY HERA. Analyzing powers of π+ and π- produced on hydrogen and carbon targets are the same. Various models to explain inclusive analyzing powers are also discussed

  6. Stable Isotope (delta OXYGEN-18, Delta Deuterium, Delta CARBON-13) Dendroclimatological Studies in the Waterloo Region of Southern Ontario, Canada, Between AD 1610 and 1990.

    Science.gov (United States)

    Buhay, William Mark

    Oxygen (delta^{18} O), hydrogen (delta^2H) and carbon (delta^{13}C) isotopes were measured in wood cellulose from elm, white pine and maple trees that grew in southwestern Ontario, Canada. The measured oxygen and hydrogen isotopic data were used for model-based reconstructions of delta^{18}{O}_{meteoric water}, mean annual temperature (MAT) and relative humidity for a period, AD 1610 to 1880, that precedes instrumental records of climate. The carbon isotope measurements were compared with the Cellulose Model inferred climate data to reveal additional environmental information. Modifications made to the Cellulose Model focused on the dynamics of oxygen and hydrogen isotopic fractionation in plants during evapotranspiration and photosynthetic assimilation. For instance, kinetic fractionation of ^{18}O was found to be predictable from theoretical considerations of leaf energy balance and boundary layer dynamics. Kinetic fractionation during evapotranspiration is sensitive to the nature of the boundary layer, which is controlled by leaf size and morphology. Generally, plants with small segmented leaves have a lower component of turbidity in the leaf boundary layer, which results in higher kinetic fractionation values, than do plants having large simple leaves and more turbulent boundary layers. Kinetic ^2H enrichment in plant leaf water can also be rationalized in terms of leaf size and morphology when an apparent temperature-dependent isotope effect, acting in opposition to evaporative enrichment, is taken into account. Accounting for this temperature -dependent isotope effect helps to: (1) reconcile hydrogen kinetic fractionation inconsistencies for different leaves; (2) explain a temperature effect previously attributed to variable biochemical fractionation during cellulose synthesis, and; (3) verify hydrogen biochemical effects in plants. This improved characterization of the oxygen and hydrogen isotopic effects in plants, using the modified Cellulose Model, helped

  7. The CD19/CD21 signal transducing complex of human B lymphocytes includes the target of antiproliferative antibody-1 and Leu-13 molecules.

    Science.gov (United States)

    Bradbury, L E; Kansas, G S; Levy, S; Evans, R L; Tedder, T F

    1992-11-01

    CD19 is a member of the Ig superfamily expressed on the surface of B lymphocytes that may be involved in the regulation of B cell function. Immunoprecipitation studies with B cell lines solubilized by digitonin have shown CD19 to be part of a multimolecular complex that includes CD21 (CR2) and other unidentified proteins. In this study, two of the CD19-associated proteins were identified as TAPA-1, which is expressed on most cell types, and Leu-13, which is expressed on subsets of lymphoid cells. TAPA-1 and Leu-13 are physically associated in many cell lineages. CD19 and CD21 mAb each specifically coprecipitated proteins of the same size as those precipitated by TAPA-1 and Leu-13 mAb from B cell lines and cDNA-transfected K562 cell lines. Western blot analysis with a TAPA-1 mAb verified the identity of TAPA-1 in CD19 and CD21 immunoprecipitated materials. In addition, when TAPA-1 or Leu-13 were crosslinked and patched on the cell surface, all of the CD19 comigrated with TAPA-1 and some of the CD19 comigrated with Leu-13. Furthermore, mAb binding to CD19, CD21, TAPA-1, and Leu-13 on B cell lines induced similar biologic responses, including the induction of homotypic adhesion, inhibition of proliferation, and an augmentation of the increase in intracellular [Ca2+] induced by suboptimal cross-linking of surface Ig on B cell lines. Together, these data suggest that TAPA-1 and Leu-13 are broadly expressed members of a signal transduction complex in which lineage-specific proteins, such as CD19 and CD21, provide cell-specific functions. PMID:1383329

  8. Carboxylic acid functionalization prevents the translocation of multi-walled carbon nanotubes at predicted environmentally relevant concentrations into targeted organs of nematode Caenorhabditis elegans

    Science.gov (United States)

    Nouara, Abdelli; Wu, Qiuli; Li, Yinxia; Tang, Meng; Wang, Haifang; Zhao, Yuliang; Wang, Dayong

    2013-06-01

    Carboxyl (-COOH) surface modified multi-walled carbon nanotubes (MWCNTs-COOH) can be used for targeted delivery of drugs and imaging. However, whether MWCNTs-COOH at environmentally relevant concentrations exert certain toxic effects on multicellular organisms and the underlying mechanisms are still largely unclear. In the present study, we applied the nematode Caenorhabditis elegans to evaluate the properties of MWCNTs-COOH at environmentally relevant concentrations by comparing the effects of MWCNTs and MWCNTs-COOH exposure on C. elegans from L1-larvae to adult at concentrations of 0.001-1000 μg L-1. Exposure to MWCNTs could potentially damage the intestine (primary targeted organ) at concentrations greater than 0.1 μg L-1 and functions of neurons and reproductive organ (secondary targeted organs) at concentrations greater than 0.001 μg L-1. Carboxyl modification prevented the toxicity of MWCNTs on the primary and the secondary targeted organs at concentrations less than 100 μg L-1, suggesting that carboxyl modification can effectively prevent the adverse effects of MWCNTs at environmentally relevant concentrations. After exposure, MWCNTs-COOH (1 mg L-1) were translocated into the spermatheca and embryos in the body through the primary targeted organs. However, MWCNTs-COOH (10 μg L-1) were not observed in spermatheca and embryos in the body of nematodes. Moreover, relatively high concentrations of MWCNTs-COOH exposed nematodes might have a hyper-permeable intestinal barrier, whereas MWCNTs-COOH at environmentally relevant concentrations effectively sustained the normally permeable state for the intestinal barrier. Therefore, we elucidated the cellular basis of carboxyl modification to prevent toxicity of MWCNTs at environmentally relevant concentrations. Our data highlights the key role of biological barriers in the primary targeted organs to block toxicity formation from MWCNTs, which will be useful for the design of effective prevention strategies against

  9. Combined δ11B, δ13C, and δ18O analyses of coccolithophore calcite constrains the response of coccolith vesicle carbonate chemistry to CO2-induced ocean acidification

    Science.gov (United States)

    Liu, Yi-Wei; Tripati, Robert; Aciego, Sarah; Gilmore, Rosaleen; Ries, Justin

    2016-04-01

    Coccolithophorid algae play a central role in the biological carbon pump, oceanic carbon sequestration, and in marine food webs. It is therefore important to understand the potential impacts of CO2-induced ocean acidification on these organisms. Differences in the regulation of carbonate chemistry, pH, and carbon sources of the intracellular compartments where coccolith formation occurs may underlie the diverse calcification and growth responses to acidified seawater observed in prior experiments. Here we measured stable isotopes of boron (δ11B), carbon13C) and oxygen (δ18O) within coccolith calcite, and δ13C of algal tissue to constrain carbonate system parameters in two strains of Pleurochrysis carterae (P. carterae). The two strains were cultured under variable pCO2, with water temperature, salinity, dissolved inorganic carbon (DIC), and alkalinity monitored. Notably, PIC, POC, and PIC/POC ratio did not vary across treatments, indicating that P. carterae is able to calcify and photosynthesize at relatively constant rates irrespective of pCO2 treatment. The δ11B data indicate that mean pH at the site of coccolith formation did not vary significantly in response to elevated CO2. These results suggest that P. carterae regulates calcifying vesicle pH, even amidst changes in external seawater pH. Furthermore, δ13C and δ18O data suggest that P. carterae may utilize carbon from a single internal DIC pool for both calcification and photosynthesis, and that a greater proportion of dissolved CO2 relative to HCO3- enters the internal DIC pool under acidified conditions. These results suggest that P. carterae is able to calcifyand photosynthesize at relatively constant rates across pCO2 treatments by maintaining pH homeostasis at their site of calcification and utilizing a greater proportion of aqueous CO2.

  10. Evidence of polycyclic aromatic hydrocarbon biodegradation in a contaminated aquifer by combined application of in situ and laboratory microcosms using (13)C-labelled target compounds.

    Science.gov (United States)

    Bahr, Arne; Fischer, Anko; Vogt, Carsten; Bombach, Petra

    2015-02-01

    The number of approaches to evaluate the biodegradation of polycyclic aromatic hydrocarbons (PAHs) within contaminated aquifers is limited. Here, we demonstrate the applicability of a novel method based on the combination of in situ and laboratory microcosms using (13)C-labelled PAHs as tracer compounds. The biodegradation of four PAHs (naphthalene, fluorene, phenanthrene, and acenaphthene) was investigated in an oxic aquifer at the site of a former gas plant. In situ biodegradation of naphthalene and fluorene was demonstrated using in situ microcosms (BACTRAP(®)s). BACTRAP(®)s amended with either [(13)C6]-naphthalene or [(13)C5/(13)C6]-fluorene (50:50) were incubated for a period of over two months in two groundwater wells located at the contaminant source and plume fringe, respectively. Amino acids extracted from BACTRAP(®)-grown cells showed significant (13)C-enrichments with (13)C-fractions of up to 30.4% for naphthalene and 3.8% for fluorene, thus providing evidence for the in situ biodegradation and assimilation of those PAHs at the field site. To quantify the mineralisation of PAHs, laboratory microcosms were set up with BACTRAP(®)-grown cells and groundwater. Naphthalene, fluorene, phenanthrene, or acenaphthene were added as (13)C-labelled substrates. (13)C-enrichment of the produced CO2 revealed mineralisation of between 5.9% and 19.7% for fluorene, between 11.1% and 35.1% for acenaphthene, between 14.2% and 33.1% for phenanthrene, and up to 37.0% for naphthalene over a period of 62 days. Observed PAH mineralisation rates ranged between 17 μg L(-1) d(-1) and 1639 μg L(-1) d(-1). The novel approach combining in situ and laboratory microcosms allowed a comprehensive evaluation of PAH biodegradation at the investigated field site, revealing the method's potential for the assessment of PAH degradation within contaminated aquifers.

  11. Recent results at the SIRa test bench: diffusion properties of carbon graphite and B{sub 4}C targets

    Energy Technology Data Exchange (ETDEWEB)

    Landre-Pellemoine, F.; Barue, C.; Gaubert, G.; Gibouin, S.; Huguet, Y.; Jardin, P.; Kandri-Rody, S.; Lecesne, N.; Leroy, R.; Lewitowicz, M.; Lichtenthaler, R.; Marry, C.; Maunoury, L.; Pacquet, J.Y.; Saint-Laurent, M.G.; Stodel, C.; Rataud, J.P.; Villari, A.C.C. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Angelique, J.C.; Orr, N.A. [Laboratoire de Physique Corpusculaire, LPC-ISMRa, CNRS-IN2P3, 14 - Caen (France); Lichtenthaler, R. [IFUSP, Sao Paulo, S.P. (Brazil); Bajeat, O.; Clapier, F.; Ducourtieux, M.; Lau, C.; Obert, J. [Institut de Physique Nucleaire (IN2P3/CNRS), 91 - Orsay (France); Bennett, R. [CLRC, RAL, Chilton Oxon (United Kingdom)

    2000-07-01

    The diffusion properties of graphite targets with 1, 4 and 15 microns microstructure has been measured for He and Ar isotopes. An important enhancement of the diffusion efficiency for the smaller microstructure is observed. A releasing efficiency of the order of 100% was obtained for {sup 6}He (T{sub 1/2} = 806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B{sub 4}C (Boron Carbide) have also been studied. Yields of 1.5 10{sup 8} pps and 10{sup 6} pps for {sup 6}He and {sup 8}He has been obtained. (authors)

  12. Total and Partial Fragmentation Cross-Section of 500 MeV/nucleon Carbon Ions on Different Target Materials

    CERN Document Server

    Alpat, Behcet; Blasko, Sandor; Caraffini, Diego; Di Capua, Francesco; Postolache, Vasile; Saltanocchi, Giorgio; Menichelli, Mauro; Desorgher, Laurent; Durante, Marco; Pleskac, Radek; La Tessa, Chiara

    2014-01-01

    By using an experimental setup based on thin and thick double-sided microstrip silicon detectors, it has been possible to identify the fragmentation products due to the interaction of very high energy primary ions on different targets. Here we report total and partial cross-sections measured at GSI (Gesellschaft fur Schwerionenforschung), Darmstadt, for 500 MeV/n energy $^{12}C$ beam incident on water (in flasks), polyethylene, lucite, silicon carbide, graphite, aluminium, copper, iron, tin, tantalum and lead targets. The results are compared to the predictions of GEANT4 (v4.9.4) and FLUKA (v11.2) Monte Carlo simulation programs.

  13. In vivo carbon-edited detection with proton echo-planar spectroscopic imaging (ICED PEPSI) : [3,4-(CH2)-C-13] glutamate/glutamine tomography in rat brain

    NARCIS (Netherlands)

    Hyder, F; Renken, R; Rothman, DL

    1999-01-01

    A method for in vivo carbon-edited detection with proton echo-planar spectroscopic imaging (ICED PEPSI) is described. This method is composed of an echo-planar based acquisition implemented with C-13-H-1 J editing spectroscopy and is intended for high temporal and spatial resolution in vivo spectros

  14. In situ 13CO2 pulse labelling of field-grown eucalypt trees revealed the effects of potassium nutrition and throughfall exclusion on phloem transport of photosynthetic carbon.

    Science.gov (United States)

    Epron, Daniel; Cabral, Osvaldo Machado Rodrigues; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo Zacharias; Trivelin, Paulo Cesar Ocheuze; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

    2016-01-01

    Potassium (K) is an important limiting factor of tree growth, but little is known of the effects of K supply on the long-distance transport of photosynthetic carbon (C) in the phloem and of the interaction between K fertilization and drought. We pulse-labelled 2-year-old Eucalyptus grandis L. trees grown in a field trial combining K fertilization (+K and -K) and throughfall exclusion (+W and -W), and we estimated the velocity of C transfer by comparing time lags between the uptake of (13)CO2 and its recovery in trunk CO2 efflux recorded at different heights. We also analysed the dynamics of the labelled photosynthates recovered in the foliage and in the phloem sap (inner bark extract). The mean residence time of labelled C in the foliage was short (21-31 h). The time series of (13)C in excess in the foliage was affected by the level of fertilization, whereas the effect of throughfall exclusion was not significant. The velocity of C transfer in the trunk (0.20-0.82 m h(-1)) was twice as high in +K trees than in -K trees, with no significant effect of throughfall exclusion except for one +K -W tree labelled in the middle of the drought season that was exposed to a more pronounced water stress (midday leaf water potential of -2.2 MPa). Our results suggest that besides reductions in photosynthetic C supply and in C demand by sink organs, the lower velocity under K deficiency is due to a lower cross-sectional area of the sieve tubes, whereas an increase in phloem sap viscosity is more likely limiting phloem transport under drought. In all treatments, 10 times less (13)C was recovered in inner bark extracts at the bottom of the trunk when compared with the base of the crown, suggesting that a large part of the labelled assimilates has been exported out of the phloem and replaced by unlabelled C. This supports the 'leakage-retrieval mechanism' that may play a role in maintaining the pressure gradient between source and sink organs required to sustain high

  15. Application of a methane carbon isotope analyzer for the investigation of δ13C of methane emission measured by the automatic chamber method in an Arctic Tundra

    Science.gov (United States)

    Mastepanov, Mikhail; Christensen, Torben

    2014-05-01

    Methane emissions have been monitored by an automatic chamber method in Zackenberg valley, NE Greenland, since 2006 as a part of Greenland Ecosystem Monitoring (GEM) program. During most of the seasons the measurements were carried out from the time of snow melt (June-July) until freezing of the active layer (October-November). Several years of data, obtained by the same method, instrumentation and at exactly the same site, provided a unique opportunity for the analysis of interannual methane flux patterns and factors affecting their temporal variability. The start of the growing season emissions was found to be closely related to a date of snow melt at the site. Despite a large between year variability of this date (sometimes more than a month), methane emission started within a few days after, and was increasing for the next about 30 days. After this peak of emission, it slowly decreased and stayed more or less constant or slightly decreasing during the rest of the growing season (Mastepanov et al., Biogeosciences, 2013). During the soil freezing, a second peak of methane emission was found (Mastepanov et al., Nature, 2008); its amplitude varied a lot between the years, from almost undetectable to comparable with total growing season emissions. Analysis of the multiyear emission patterns (Mastepanov et al., Biogeosciences, 2013) led to hypotheses of different sources for the spring, summer and autumn methane emissions, and multiyear cycles of accumulation and release of these components to the atmosphere. For the further investigation of this it was decided to complement the monitoring system with a methane carbon isotope analyzer (Los Gatos Research, USA). The instrument was installed during 2013 field season and was successfully operating until the end of the measurement campaign (27 October). Detecting both 12C-CH4 and 13C-CH4 concentrations in real time (0.5 Hz) during automatic chamber closure (15 min), the instrument was providing data for determination of

  16. In situ 13CO2 pulse labelling of field-grown eucalypt trees revealed the effects of potassium nutrition and throughfall exclusion on phloem transport of photosynthetic carbon.

    Science.gov (United States)

    Epron, Daniel; Cabral, Osvaldo Machado Rodrigues; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo Zacharias; Trivelin, Paulo Cesar Ocheuze; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

    2016-01-01

    Potassium (K) is an important limiting factor of tree growth, but little is known of the effects of K supply on the long-distance transport of photosynthetic carbon (C) in the phloem and of the interaction between K fertilization and drought. We pulse-labelled 2-year-old Eucalyptus grandis L. trees grown in a field trial combining K fertilization (+K and -K) and throughfall exclusion (+W and -W), and we estimated the velocity of C transfer by comparing time lags between the uptake of (13)CO2 and its recovery in trunk CO2 efflux recorded at different heights. We also analysed the dynamics of the labelled photosynthates recovered in the foliage and in the phloem sap (inner bark extract). The mean residence time of labelled C in the foliage was short (21-31 h). The time series of (13)C in excess in the foliage was affected by the level of fertilization, whereas the effect of throughfall exclusion was not significant. The velocity of C transfer in the trunk (0.20-0.82 m h(-1)) was twice as high in +K trees than in -K trees, with no significant effect of throughfall exclusion except for one +K -W tree labelled in the middle of the drought season that was exposed to a more pronounced water stress (midday leaf water potential of -2.2 MPa). Our results suggest that besides reductions in photosynthetic C supply and in C demand by sink organs, the lower velocity under K deficiency is due to a lower cross-sectional area of the sieve tubes, whereas an increase in phloem sap viscosity is more likely limiting phloem transport under drought. In all treatments, 10 times less (13)C was recovered in inner bark extracts at the bottom of the trunk when compared with the base of the crown, suggesting that a large part of the labelled assimilates has been exported out of the phloem and replaced by unlabelled C. This supports the 'leakage-retrieval mechanism' that may play a role in maintaining the pressure gradient between source and sink organs required to sustain high

  17. Nanostructured diamond-like carbon on digital versatile disc as a matrix-free target for laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Najam-ul-Haq, Muhammad; Rainer, Matthias; Huck, Christian W; Hausberger, Peter; Kraushaar, Harald; Bonn, Günther K

    2008-10-01

    A nanostructured diamond-like carbon (DLC) coated digital versatile disk (DVD) target is presented as a matrix-free sample support for application in laser desorption/ionization mass spectrometry (LDI-MS). A large number of vacancies, defects, relative sp(2) carbon content, and nanogrooves of DLC films support the LDI phenomenon. The observed absorptivity of DLC is in the range of 305-330 nm (nitrogen laser, 337 nm). The universal applicability is demonstrated through different analytes like amino acids, carbohydrates, lipids, peptides, and other metabolites. Carbohydrates and amino acids are analyzed as sodium and potassium adducts. Peptides are detectable in their protonated forms, which avoid the extra need of additives for ionization. A bovine serum albumin (BSA) digest is analyzed to demonstrate the performance for peptide mixtures, coupled with the material-enhanced laser desorption/ionization (MELDI) approach. The detection limit of the described matrix-free target is investigated to be 10 fmol/microL for [Glu(1)]-fibrinopeptide B (m/z 1570.6) and 1 fmol/microL for L-sorbose (Na(+) adduct). The device does not require any chemical functionalization in contrast to other matrix-free systems. The inertness of DLC provides longer lifetimes without any deterioration in the detection sensitivity. Broad applicability allows high performance analysis in metabolomics and peptidomics. Furthermore the DLC coated DVD (1.4 GB) sample support is used as a storage device for measured and processed data together with sampling on a single device. PMID:18729472

  18. Application of (13)C ramp CPMAS NMR with phase-adjusted spinning sidebands (PASS) for the quantitative estimation of carbon functional groups in natural organic matter.

    Science.gov (United States)

    Ikeya, Kosuke; Watanabe, Akira

    2016-01-01

    The composition of carbon (C) functional groups in natural organic matter (NOM), such as dissolved organic matter, soil organic matter, and humic substances, is frequently estimated using solid-state (13)C NMR techniques. A problem associated with quantitative analysis using general cross polarization/magic angle spinning (CPMAS) spectra is the appearance of spinning side bands (SSBs) split from the original center peaks of sp (2) hybridized C species (i.e., aromatic and carbonyl C). Ramp CP/phase-adjusted side band suppressing (PASS) is a pulse sequence that integrates SSBs separately and quantitatively recovers them into their inherent center peaks. In the present study, the applicability of ramp CP/PASS to NOM analysis was compared with direct polarization (DPMAS), another quantitative method but one that requires a long operation time, and/or a ramp CP/total suppression side band (ramp CP/TOSS) technique, a popular but non-quantitative method for deleting SSBs. The test materials were six soil humic acid samples with various known degrees of aromaticity and two fulvic acids. There were no significant differences in the relative abundance of alkyl C, O-alkyl C, and aromatic C between the ramp CP/PASS and DPMAS methods, while the signal intensities corresponding to aromatic C in the ramp CP/TOSS spectra were consistently less than the values obtained in the ramp CP/PASS spectra. These results indicate that ramp CP/PASS can be used to accurately estimate the C composition of NOM samples.

  19. Biomarker and carbon isotope constraints (δ13C, Δ14C) on sources and cycling of particulate organic matter discharged by large Siberian rivers draining permafrost areas

    International Nuclear Information System (INIS)

    Circumpolar permafrost soils store about half of the global soil organic carbon pool. These huge amounts of organic matter (OM) could accumulate due to low temperatures and water saturated soil conditions over the course of millennia. Currently most of this OM remains frozen and therefore does not take part in the active carbon cycle, making permafrost soils a globally important carbon sink. Over the last decades mean annual air temperatures in the Arctic increased stronger than the global mean and this trend is projected to continue. As a result the permafrost carbon pool is under climate pressure possibly creating a positive climate feedback due to the thaw-induced release of greenhouse gases to the atmosphere. Arctic warming will lead to increased annual permafrost thaw depths and Arctic river runoff likely resulting in enhanced mobilization and export of old, previously frozen soil-derived OM. Consequently, the great arctic rivers play an important role in global biogeochemical cycles by connecting the large permafrost carbon pool of their hinterlands with the arctic shelf seas and the Arctic Ocean. The first part of this thesis deals with particulate organic matter (POM) from the Lena Delta and adjacent Buor Khaya Bay. The Lena River in central Siberia is one of the major pathways translocating terrestrial OM from its southernmost reaches near Lake Baikal to the coastal zone of the Laptev Sea. The permafrost soils from the Lena catchment area store huge amounts of pre-aged OM, which is expected to be remobilized due to climate warming. To characterize the composition and vegetation sources of OM discharged by the Lena River, the lignin phenol and carbon isotopic composition (δ13C and Δ14C) in total suspended matter (TSM) from surface waters, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex) were analyzed. The lignin compositions of these samples are consistent

  20. Ammonium carbonate loss rates from lures differentially affect trap captures of Rhagoletis indifferens (Diptera: Tephritidae) and non-target flies

    Science.gov (United States)

    Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is a pest of cherry (Prunus spp.) in western North America that can be monitored using traps baited with ammonia. However, ammonia-based attractants also attract non-target Diptera that clutter traps. Here, the hypothe...

  1. Determination of Each Province's Carbon Dioxide Reduction Target Based on Embodied Carbon Dioxide Emissions%基于隐含碳排放的碳减排目标研究

    Institute of Scientific and Technical Information of China (English)

    张增凯; 郭菊娥; 安尼瓦尔·阿木提

    2011-01-01

    中国政府以2005年为基年提出了碳减排指标,确定各省碳减排基数对于明确各省碳减排责任具有重要意义.本文结合“十一五”期间节能指标分解过程中存在的问题,分析了省际贸易中隐含的碳排放对于确定各省碳减排基数的影响,并分别基于生产者负责原则和消费者负责原则计算了“十二五”期间各省碳减排基数.计算结果表明:①将工业部门拆分为23个部门能够更加充分反映省际贸易结构差异对于隐含碳排放计算的影响;②省际贸易中隐含碳排放不仅在各省间有较大差异而且呈现出从中西部地区调往东部地区的整体转移方向;③不同原则下各省碳减排基数计算结果存在较大差异,消费者负责原则更加真实地反映了各地区实际减排责任,避免了部分省份通过省际调进代替本省生产的方式实现碳减排目标.%Measuring each province's carbon dioxide emissions is of great significance for the carbon reduction target, announced by Chinese Central Government, with 2005 as the base year. This paper firstly analyzes the existing problems of the energy conservation during the Eleventh Five Year Plan period and then studies the influence of embodied carbon dioxide emissions on the calculation of each province' s carbon emissions basis. Finally, each province' s carbon dioxide emissions of the base year are calculated based on two principles: the producer responsibility principle and the consumer responsibility principle. Several crucial conclusions are drawn as follows. First, dividing the industrial sector into 23 sectors adequately reflects the influence of the structural difference in inter-provincial trade on the calculation of the embodied carbon dioxide emissions. Second, the provincial differences of embodied carbon dioxide emissions are obvious. The transfer direction of embodied carbon dioxide emissions is from the central and western regions to the eastern

  2. Recent results at the SIRa test bench Diffusion properties of carbon graphite and B sub 4 C targets

    CERN Document Server

    Landre-Pellemoine, F; Bajeat, O; Barue, C; Bennett, R; Clapier, F; Ducourtieux, M; Gaubert, G; Gibouin, S; Huguet, Y; Jardin, P; Kandri-Rody, S; Lau, C; Lecesne, N; Leroy, R; Lewitowicz, M; Lichtenthäler, R; Marry, C; Maunoury, L; Obert, J; Orr, N A; Pacquet, J Y; Saint-Laurent, M G; Stodel, C; Rataud, J P; Villari, A C C

    2002-01-01

    The diffusion properties of graphite targets with 1, 4 and 15 microns microstructure has been measured for He and Ar isotopes. An important enhancement of the diffusion efficiency for the smaller microstructure is observed. A releasing efficiency of the order of 100% was obtained for sup 6 He (T sub 1 sub / sub 2 =806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B sub 4 C (boron carbide) have also been studied. Yields of 1.4x10 sup 8 pps and 5.0x10 sup 5 pps for sup 6 He and sup 8 He has been obtained.

  3. A competitive strategy coupled with endonuclease-assisted target recycling for DNA detection using silver-nanoparticle-tagged carbon nanospheres as labels.

    Science.gov (United States)

    Zhu, Zhu; Gao, Fenglei; Lei, Jianping; Dong, Haifeng; Ju, Huangxian

    2012-10-22

    A simple competitive strategy was designed for the sensitive detection of sequence-specific DNA by combining endonuclease-assisted target recycling and electrochemical stripping analysis of silver nanoparticles (AgNPs). The AgNP-tagged carbon nanospheres were synthesized by means of in situ reduction of Ag(+) adsorbed onto a negatively charged polyelectrolyte layer and functionalized with streptavidin for binding biotin-labeled DNA strands. The labeled strand was captured on the DNA sensor surface by competitive hybridization of biotinated primer 1 and its cleaved product. The cleaved product could be amplified in homogeneous solution by endonuclease-assisted target recycling with a Y-shaped junction DNA structure, thus leading to the correlation of the stripping signal to the target concentration. The functionalized nanosphere was characterized with X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The proposed method showed a linear range from 0.1 to 1000 fM with a limit of detection of 0.066 fM (3σ) and good selectivity for base discrimination. The designed strategy provided a sensitive tool for DNA analysis and could be widely applied in bioanalysis and biomedicine.

  4. Co-regulation of the DAF-16 target gene, cyp-35B1/dod-13, by HSF-1 in C. elegans dauer larvae and daf-2 insulin pathway mutants.

    Directory of Open Access Journals (Sweden)

    Wendy B Iser

    Full Text Available Insulin/IGF-I-like signaling (IIS has both cell autonomous and non-autonomous functions. In some cases, targets through which IIS regulates cell-autonomous functions, such as cell growth and metabolism, have been identified. In contrast, targets for many non-autonomous IIS functions, such as C. elegans dauer morphogenesis, remain elusive. Here, we report the use of genomic and genetic approaches to identify potential non-autonomous targets of C. elegans IIS. First, we used transcriptional microarrays to identify target genes regulated non-autonomously by IIS in the intestine or in neurons. C. elegans IIS controls expression of a number of stress response genes, which were differentially regulated by tissue-restricted IIS. In particular, expression of sod-3, a MnSOD enzyme, was not regulated by tissue-restricted IIS on the microarrays, while expression of hsp-16 genes was rescued back to wildtype by tissue restricted IIS. One IIS target regulated non-autonomously by age-1 was cyp-35B1/dod-13, encoding a cytochrome P450. Genetic analysis of the cyp-35B1 promoter showed both DAF-16 and HSF-1 are direct regulators. Based on these findings, we propose that hsf-1 may participate in the pathways mediating non-autonomous activities of age-1 in C. elegans.

  5. 13Cr系列不锈钢在模拟井下介质中的CO2腐蚀研究%INVESTIGATION ON CARBON DIOXIDE CORROSION PERFORMANCE OF VARIOUS 13Cr STEELS IN SIMULATED STRATUM WATER

    Institute of Scientific and Technical Information of China (English)

    侯赞; 周庆军; 王起江; 张忠铧; 齐慧滨; 王俊

    2012-01-01

    The corrosion behaviour of various 13Cr steels (marked as 13Cr-0, 13Cr1, M13Cr and S13Cr) in the CO2 corrosion environment was investigated by high temperature and high pressure (HTHP) autoclave under conditions of different temperatures, concentrations of Cl ion and partial pressures of CO2 to simulate the downhole surroundings of a certain oil field. Their corrosion scales were observed and analyzed by scanning elec- tron microscope(SEM), energy dispersive spectrometer(EDS), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). The results shown that corrosion rates of all steels increased with rising of temperature, concentration of Cl ion and CO2 partial pressure; temperature had the most notable impact on corrosion rates, at a high temperature, the four 13Cr steels exhibited conspicuous differences in corrosion rates; the order of corrosion rates of the four steels was 13Cr-0〉13Cr-1〉M13Cr〉S13Cr. Furthermore, the morphologies and microstructures of corrosion scales on different steels differed significantly from each other.%根据某油田不同井况条件,配制不同井下模拟溶液,用高温高压釜研究了4种不同成分的13Cr马氏体不锈钢在不同温度、Cl^-浓度和CO2分压下的腐蚀行为,对腐蚀性能进行了评价,用SEM,EDS,XRD和XPS等方法对腐蚀产物的形貌与成分进行了观察分析。结果表明,随着温度的升高及Cl^-浓度和CO2分压的增大,13Cr系列不锈钢的腐蚀速率均相应增大,腐蚀速率由高到低的排序为13Cr-0〉13Cr-1〉M13Cr〉S13Cr;其腐蚀产物膜的形貌与结构也有明显差异。

  6. The synthesis of [14C]-3S,4R-4-(4-fluorophenyl)-3-(3,4-methylenedioxyphenoxymethyl) piperidine hydrochloride (BRL 29060A), and mechanistic studies using carbon-13 labelling

    International Nuclear Information System (INIS)

    Paroxetine, BRL 29060A has been labelled with both carbon-14 and carbon-13. Hydroxymethylation of 4-(4-fluorophenyl)-1-methyl-1,2,5,6-tetrahydropyridine, using [14C]formaldehyde, produced an enantiomeric mixture of products which was taken without separation through a multistage sequence. Resolution of the mixture of stereoisomers at the penultimate step gave [14C]BRL 29060A with the required configuration. The overall radiochemical yield was 8%. At some stage in this process, as shown by C-13 labelling studies, scrambling of the label took place to give BRL 29060A with the majority of the label in the C-2 position of the piperidine ring and the remainder at the expected 7-methylene position. Further investigations of this route using carbon-13 as the label are described. When sesamol, (3,4-methylenedioxyphenol) was reacted with the O-benzene sulphonate of -cis-4-(4-fluorophenyl)-3-(hydroxy[13C]methyl-l-methylpiperidine, an inversion of configuration resulted via the previously described 1-aza[3.1.1]bicycloheptane ring system. It is also shown that the corresponding -trans-substituted piperidine, under similar conditions, does not undergo this inversion. (Author)

  7. The synthesis of [[sup 14]C]-3S,4R-4-(4-fluorophenyl)-3-(3,4-methylenedioxyphenoxymethyl) piperidine hydrochloride (BRL 29060A), and mechanistic studies using carbon-13 labelling

    Energy Technology Data Exchange (ETDEWEB)

    Willcocks, K.; Rustidge, D.C.; Tidy, D.J.D. (SmithKline Beecham Pharmaceuticals Research Div., Harlow (United Kingdom)); Barnes, R.D. (SmithKline Beecham Pharmaceuticals Div., Betchworth (United Kingdom). Chemotherapeutic Research Centre)

    1993-01-01

    Paroxetine, BRL 29060A has been labelled with both carbon-14 and carbon-13. Hydroxymethylation of 4-(4-fluorophenyl)-1-methyl-1,2,5,6-tetrahydropyridine, using [[sup 14]C]formaldehyde, produced an enantiomeric mixture of products which was taken without separation through a multistage sequence. Resolution of the mixture of stereoisomers at the penultimate step gave [[sup 14]C]BRL 29060A with the required configuration. The overall radiochemical yield was 8%. At some stage in this process, as shown by C-13 labelling studies, scrambling of the label took place to give BRL 29060A with the majority of the label in the C-2 position of the piperidine ring and the remainder at the expected 7-methylene position. Further investigations of this route using carbon-13 as the label are described. When sesamol, (3,4-methylenedioxyphenol) was reacted with the O-benzene sulphonate of -cis-4-(4-fluorophenyl)-3-(hydroxy[[sup 13]C]methyl-l-methylpiperidine), an inversion of configuration resulted via the previously described 1-aza[3.1.1]bicycloheptane ring system. It is also shown that the corresponding -trans-substituted piperidine, under similar conditions, does not undergo this inversion. (Author).

  8. Platinum-coordinated graphitic carbon nitride nanosheet used for targeted inhibition of amyloid β-peptide aggregation

    Institute of Scientific and Technical Information of China (English)

    Meng Li; Yijia Guan; Zhaowei Chen; Nan Gao; Jinsong Ren; Kai Dong; Xiaogang Qu

    2016-01-01

    Amyloid β-peptide (Aβ) aggregation is a critical step in the pathogenesis of Alzheimer's disease (AD).Inhibition of Aβ production,dissolution of existing aggregates and clearance of Aβ represent valid therapeutic strategies against AD.Herein,a novel platinum(Ⅱ)-coordinated graphitic carbon nitride (g-C3N4)nanosheet (g-C3N4@Pt) has been designed to covalently bind to Aβ and modulate the peptide's aggregation and toxicity.Furthermore,g-C3N4@Pt nanosheets possess high photocatalytic activity and can oxygenate Aβ upon visible light irradiation,remarkably attenuating both the aggregation potency and neurotoxidty of Aβ.Due to its ability to cross the blood-brain barrier (BBB) and its good biocompatibility,g-C3N4@Pt nanosheet is a promising inhibitor of Aβ aggregation.This study may serve as a model for the engineering of novel multifunctional nanomaterials used for the treatment of AD.

  9. Formation of short-lived positron emitters in reactions of protons of energies up to 200 MeV with the target elements carbon, nitrogen and oxygen

    CERN Document Server

    Kettern, K; Qaim, S M; Shubin, Yu N; Steyn, G F; Van der Walt, T N; 10.1016/j.apradiso.2004.02.007

    2004-01-01

    Excitation functions were measured by the stacked-foil technique for proton induced reactions on carbon, nitrogen and oxygen leading to the formation of the short-lived positron emitters /sup 11/C (T/sub 1 /2/=20.38 min) and /sup 13/N (T/sub 1/2/=9.96 min). The energy region covered extended up to 200 MeV. The product activity was measured non-destructively via gamma -ray spectrometry. A careful decay curve analysis of the positron annihilation radiation was invariably performed. The experimental results were compared with theoretical data obtained using the modified hybrid nuclear model code ALICE-IPPE for intermediate energies. The agreement was found to be generally satisfactory. The data are of importance in proton therapy.

  10. High resolution {sup 13}C NMR spectra on oriented lipid bilayers: From quantifying the various sources of line broadening to performing 2D experiments with 0.2-0.3 ppm resolution in the carbon dimension

    Energy Technology Data Exchange (ETDEWEB)

    Soubias, O.; Saurel, O.; Reat, V.; Milon, A. [Institut de Pharmacologie et de Biologie Structurale (France)], E-mail: alain.milon@ipbs.fr

    2002-09-15

    {sup 13}C NMR spectra routinely performed on oriented lipid bilayers display linewidth of 1-2 ppm, although T{sub 2} measurements indicate that 0.1-0.2 ppm could be obtained. We have prepared a DMPC - {sup 13}C{sub 4}-cholesterol (7/3) sample, and oriented the lipid bilayers between glass plates so that the bilayer normal makes an angle of 90 deg. (or of the magic angle) with B{sub 0}. We have measured T{sub 2}s, CSAs, and linewidths for the choline {sup 13}C-{gamma}-methyl, the cholesterol-C{sub 4} carbons and the lipid head group phosphorus, at both angles and 313 K. The magnetic field distribution within the sample was calculated using the surface current formalism. The line shapes were simulated as a function of B{sub 0} field inhomogeneities and sample mosaic spread. Both effects contribute to the experimental linewidth. Using three signals of different CSA, we have quantified both contributions and measured the mosaic spread accurately. Direct shimming on a sample signal is essential to obtain sharp resonances and {sup 13}C labelled choline methyl resonance of DMPC is a good candidate for this task. After optimisation of the important parameters (shimming on the choline resonance, mosaic spread of {+-} 0.30 deg.), {sup 13}C linewidth of 0.2-0.3 ppm have been obtained. This newly achieved resolution on bilayers oriented at 90 deg., has allowed to perform two 2D experiments, with a good sensitivity: 2D PELF (correlation of carbon chemical shifts and C-H dipolar couplings) and 2D D-resolved experiment (correlation of carbon chemical shifts and C-C dipolar couplings). A C-C dipolar coupling of 35 {+-} 2 Hz between the choline methyl carbons was determined.

  11. Direct Solvent-Derived Polymer-Coated Nitrogen-Doped Carbon Nanodots with High Water Solubility for Targeted Fluorescence Imaging of Glioma.

    Science.gov (United States)

    Wang, Yi; Meng, Ying; Wang, Shanshan; Li, Chengyi; Shi, Wei; Chen, Jian; Wang, Jianxin; Huang, Rongqin

    2015-08-01

    Cancer imaging requires biocompatible and bright contrast-agents with selective and high accumulation in the tumor region but low uptake in normal tissues. Herein, 1-methyl-2-pyrrolidinone (NMP)-derived polymer-coated nitrogen-doped carbon nanodots (pN-CNDs) with a particle size in the range of 5-15 nm are prepared by a facile direct solvothermal reaction. The as-prepared pN-CNDs exhibit stable and adjustable fluorescence and excellent water solubility. Results of a cell viability test (CCK-8) and histology analysis both demonstrate that the pN-CNDs have no obvious cytotoxicity. Most importantly, the pN-CNDs can expediently enter glioma cells in vitro and also mediate glioma fluorescence imaging in vivo with good contrast via elevated passive targeting. PMID:25808813

  12. Comparison of the regiospecific distribution from triacylglycerols after chemical and enzymatic interesterification of high oleic sunflower oil and fully hydrogenated high oleic sunflower oil blend by carbon-13 nuclear magnetic resonance.

    Science.gov (United States)

    Lopes, Thiago I B; Ribeiro, Marilene D M M; Ming, Chiu C; Grimaldi, Renato; Gonçalves, Lireny A G; Marsaioli, Anita J

    2016-12-01

    The nutritional and organoleptic attributes of oils can proceed via interesterification of oils blends catalyzed by enzymes or chemicals. Enzymatic interesterification processes are preferred due the regiospecific outcome. Traditionally, monitoring of distribution of fatty acids (FA) in glycerol backbone is performed by enzymatic and chromatographic methods that are time-consuming, involving a series of chemical manipulations employing large volumes of organic solvents. Alternatively, carbon-13 nuclear magnetic resonance ((13)C NMR) is a fast and reliable technique that could be applied to determine the saturated and unsaturated FA distribution of the triacylglycerols (TAGs) present in high oleic sunflower oil (SO) and fully hydrogenated high oleic sunflower oil (HSO) blends and their interesterification products. The enzymatic interesterification was conducted employing the immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM), the results show that the process was not completely regiospecific at sn-1,3 positions, due to the spontaneous acyl migration from position sn-2 to sn-1,3.

  13. Comparison of the regiospecific distribution from triacylglycerols after chemical and enzymatic interesterification of high oleic sunflower oil and fully hydrogenated high oleic sunflower oil blend by carbon-13 nuclear magnetic resonance.

    Science.gov (United States)

    Lopes, Thiago I B; Ribeiro, Marilene D M M; Ming, Chiu C; Grimaldi, Renato; Gonçalves, Lireny A G; Marsaioli, Anita J

    2016-12-01

    The nutritional and organoleptic attributes of oils can proceed via interesterification of oils blends catalyzed by enzymes or chemicals. Enzymatic interesterification processes are preferred due the regiospecific outcome. Traditionally, monitoring of distribution of fatty acids (FA) in glycerol backbone is performed by enzymatic and chromatographic methods that are time-consuming, involving a series of chemical manipulations employing large volumes of organic solvents. Alternatively, carbon-13 nuclear magnetic resonance ((13)C NMR) is a fast and reliable technique that could be applied to determine the saturated and unsaturated FA distribution of the triacylglycerols (TAGs) present in high oleic sunflower oil (SO) and fully hydrogenated high oleic sunflower oil (HSO) blends and their interesterification products. The enzymatic interesterification was conducted employing the immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM), the results show that the process was not completely regiospecific at sn-1,3 positions, due to the spontaneous acyl migration from position sn-2 to sn-1,3. PMID:27374579

  14. Comparative phenomics and targeted use of genomics reveals variation in carbon and nitrogen assimilation among different Brettanomyces bruxellensis strains.

    Science.gov (United States)

    Crauwels, S; Van Assche, A; de Jonge, R; Borneman, A R; Verreth, C; Troels, P; De Samblanx, G; Marchal, K; Van de Peer, Y; Willems, K A; Verstrepen, K J; Curtin, C D; Lievens, B

    2015-11-01

    Recent studies have suggested a correlation between genotype groups of Brettanomyces bruxellensis and their source of isolation. To further explore this relationship, the objective of this study was to assess metabolic differences in carbon and nitrogen assimilation between different B. bruxellensis strains from three beverages, including beer, wine, and soft drink, using Biolog Phenotype Microarrays. While some similarities of physiology were noted, many traits were variable among strains. Interestingly, some phenotypes were found that could be linked to strain origin, especially for the assimilation of particular α- and β-glycosides as well as α- and β-substituted monosaccharides. Based upon gene presence or absence, an α-glucosidase and β-glucosidase were found explaining the observed phenotypes. Further, using a PCR screen on a large number of isolates, we have been able to specifically link a genomic deletion to the beer strains, suggesting that this region may have a fitness cost for B. bruxellensis in certain fermentation systems such as brewing. More specifically, none of the beer strains were found to contain a β-glucosidase, which may have direct impacts on the ability for these strains to compete with other microbes or on flavor production. PMID:26135985

  15. Study of secondary electron emission from thin carbon targets with swift charged particles: heavy ions, hydrogen ions; Etude experimentale de l`emission electronique secondaire de cibles minces de carbone sous l`impact de projectiles rapides: ions lourds, ions hydrogene (atomiques, moleculaires ou sous forme d`agregats)

    Energy Technology Data Exchange (ETDEWEB)

    Billebaud, A.

    1995-07-12

    The main subject of this work is the study of electron emission from the two surfaces of thin solid targets bombarded with swift charged particles. The slowing down of swift ions in matter is mainly due to inelastic interaction with target electrons (ionization, excitation): the energy transfer to target electrons is responsible for the secondary electron emission process. The phenomenological and theoretical descriptions of this phenomena are the subject of the first chapter. We focused on secondary electron emission induced by different kind of projectiles on thin carbon foils. In chapter two we describe hydrogen cluster induced electron emission measurement between 40 and 120 keV/proton. These projectiles, composed of several atoms, allowed us to study and highlight collective effects of the electron emission process. We extended our study of electron emission to molecular (H{sub 2}{sup +}, H{sub 3}{sup +}) and composite (H{sup -}, H{sup 0}) projectiles at higher energies (<= 2 MeV): we have designed an experimental set-up devoted to electron emission statistics measurements which allowed us to study, among others things, the role of projectile electrons in secondary electron emission. This experiment is described in the third chapter. Finally, the fourth chapter describes new measurements of electron emission induced by energetic (13 MeV/u) and highly charged argon ion provided by the medium energy beam line (SME) of GANIL (Caen), which have been analyzed in the framework of a semi-empirical model of secondary electron emission. This set of experiments brings new results on composite projectile interaction with matter, and on the consequences of high energy deposition in solids. (author).

  16. Targeted Fe-filled carbon nanotube as a multifunctional contrast agent for thermoacoustic and magnetic resonance imaging of tumor in living mice.

    Science.gov (United States)

    Ding, Wenzheng; Lou, Cunguang; Qiu, Jieshan; Zhao, Zongbin; Zhou, Quan; Liang, Minjie; Ji, Zhong; Yang, Sihua; Xing, Da

    2016-01-01

    Microwave-induced thermoacoustic imaging (TAI) can map the microwave absorption distribution of targets, which depends on the electrical and magnetic properties. Although carbon nanotubes (CNTs) with good electrical properties have been used as TAI contrast agents, the negligible magnetic absorption hinders its application for sensitive detection. In order to exploit CNTs with electrical and magnetic absorption properties as agent of TAI, the ferromagnetic material-filled multi-walled CNTs (MMWCNTs) are investigated. In this study, the folic acid conjugated plain multiwalled CNTs (MWCNTs) and MMWCNTs were injected through the tail-vein of mice separately, and TAI and magnetic resonance imaging (MRI) were performed. The results show the MMWCNTs can clearly image the size and edge of the tumor with the TAI contrast enhancement of 67% and T2 signal intensity decrease of four fifths compared to MWCNTs. This study demonstrated the hybrid particles have the potential to be a high-sensitive contrast agent for accurate tumor detection. From the Clinical Editor: Novel imaging modalities are emerging. Microwave-induced thermoacoustic imaging (TAI) relies on the absorption distribution of microwave of targets. In this article the authors investigate the use of ferromagnetic material-filled multi-walled CNTs as contrast agents for both TAI and MRI in an in-vivo model for tumors. The positive findings would imply that the application of dual-modality probe could provide more accurate imaging for the clinical setting.

  17. Expressional profiling of prostate cancer risk SNPs at 11q13.5 identifies DGAT2 as a new target gene.

    Science.gov (United States)

    Nurminen, Riikka; Rantapero, Tommi; Wong, Swee C; Fischer, Daniel; Lehtonen, Rainer; Tammela, Teuvo L J; Nykter, Matti; Visakorpi, Tapio; Wahlfors, Tiina; Schleutker, Johanna

    2016-08-01

    A total of nine non-coding variants on 11q13.5 predispose men to prostate cancer (PrCa). rs200331695 within the EMSY intron is associated with aggressive PrCa and two high linkage disequilibrium (LD) groups of single-nucleotide polymorphisms (SNPs) in the intergenic region are associated with PrCa death. Here, the cis-effect of the SNPs on gene expression using expression quantitative trait loci analysis was investigated. The regulatory potential was screened in prostate tumors (n = 41) and in whole blood (n = 99). The results were validated in a second tumor set (n = 41), in lymphoblastoid cell lines (LCLs) (n = 38), and using the GTEx Portal. The effects of haplotypes were analyzed in the whole blood. The high LD SNPs (rs143975731, rs12277366, rs2155225, and rs2155222) were associated with DGAT2 expression in both tumors sets (screening P = 0.035-0.043; validation P = 0.005-0.018). The PrCa death-associated alleles decreased the expression by two-fold. rs200331695 decreased DGAT2 expression in LCLs (P = 0.006). The findings of SNPs regulating CAPN5 (P = 0.026-0.046) and AP001189.4 (P = 0.03-0.039) in the whole blood were not observed in LCLs, but the association with AP001189.4 expression was validated via the GTEx Portal (P = 8.7 × 10(-5) to 4.3 × 10(-4) ), which suggests that the high LD intergenic SNPs exert a tissue-dependent effect on the expression of two genes. No haplotypes including the risk SNPs at 11q13.5 were associated with gene expression and PrCa. The findings indicate the functionality of the PrCa death-predisposing SNPs rs143975731, rs12277366, rs2155225, and rs2155222 as DGAT2 regulators in prostate tumors. © 2016 Wiley Periodicals, Inc. PMID:27113481

  18. Catalytic conversion of carbon dioxide into dimethyl carbonate using reduced copper-cerium oxide catalysts as low as 353 K and 1.3 MPa and the reaction mechanism

    Directory of Open Access Journals (Sweden)

    Seiki eWada

    2013-06-01

    Full Text Available Synthesis of dimethyl carbonate (DMC from CO2 and methanol under milder reaction conditions was performed using reduced cerium oxide catalysts and reduced copper-promoted Ce oxide catalysts. Although the conversion of methanol was low (0.005–0.11% for 2 h of reaction, DMC was synthesized as low as 353 K and at total pressure of as low as 1.3 MPa using reduced Cu–CeO2 catalyst (0.5 wt% of Cu. The apparent activation energy was 120 kJ mol–1 and the DMC synthesis rates were proportional to the partial pressure of CO2. An optimum amount of Cu addition to CeO2 was 0.1 wt% for DMC synthesis under the conditions at 393 K and total pressure of 1.3 MPa for 2 h (conversion of methanol: 0.15% due to the compromise of two effects of Cu: the activation of H2 during reduction prior to the kinetic tests and the block (cover of the surface active site. The reduction effects in H2 were monitored through the reduction of Ce4+ sites to Ce3+ based on the shoulder peak intensity at 5727 eV in the Ce L3-edge X-ray absorption near-edge structure (XANES. The Ce3+ content was 10% for reduced CeO2 catalyst whereas it increased to 15% for reduced Cu–CeO2 catalyst (0.5wt% of Cu. Moreover, the content of reduced Ce3+ sites (10% associated with the surface O vacancy (defect sites decreased to 5% under CO2 at 290 K for reduced Cu–CeO2 catalyst (0.1wt% of Cu. The adsorption step of CO2 on the defect sites might be the key step in DMC synthesis and thus the DMC synthesis rate dependence on the partial pressure of CO2 was proportional. Subsequent H atom subtraction steps from methanol at the neighboring surface Lewis base sites should combine two methoxy species to the adsorbed CO2 to form DMC, water, and restore the surface O vacancy.

  19. Catalytic conversion of carbon dioxide into dimethyl carbonate using reduced copper-cerium oxide catalysts as low as 353 K and 1.3 MPa and the reaction mechanism

    Science.gov (United States)

    Wada, Seiki; Oka, Kazuki; Watanabe, Kentaro; Izumi, Yasuo

    2013-06-01

    Synthesis of dimethyl carbonate (DMC) from CO2 and methanol under milder reaction conditions was performed using reduced cerium oxide catalysts and reduced copper-promoted Ce oxide catalysts. Although the conversion of methanol was low (0.005-0.11%) for 2 h of reaction, DMC was synthesized as low as 353 K and at total pressure of as low as 1.3 MPa using reduced Cu-CeO2 catalyst (0.5 wt% of Cu). The apparent activation energy was 120 kJ mol-1 and the DMC synthesis rates were proportional to the partial pressure of CO2. An optimum amount of Cu addition to CeO2 was 0.1 wt% for DMC synthesis under the conditions at 393 K and total pressure of 1.3 MPa for 2 h (conversion of methanol: 0.15%) due to the compromise of two effects of Cu: the activation of H2 during reduction prior to the kinetic tests and the block (cover) of the surface active site. The reduction effects in H2 were monitored through the reduction of Ce4+ sites to Ce3+ based on the shoulder peak intensity at 5727 eV in the Ce L3-edge X-ray absorption near-edge structure (XANES). The Ce3+ content was 10% for reduced CeO2 catalyst whereas it increased to 15% for reduced Cu-CeO2 catalyst (0.5wt% of Cu). Moreover, the content of reduced Ce3+ sites (10%) associated with the surface O vacancy (defect sites) decreased to 5% under CO2 at 290 K for reduced Cu-CeO2 catalyst (0.1wt% of Cu). The adsorption step of CO2 on the defect sites might be the key step in DMC synthesis and thus the DMC synthesis rate dependence on the partial pressure of CO2 was proportional. Subsequent H atom subtraction steps from methanol at the neighboring surface Lewis base sites should combine two methoxy species to the adsorbed CO2 to form DMC, water, and restore the surface O vacancy.

  20. 全球长期减排目标与碳排放权分配原则%Long-Term Climate Change Mitigation Target and Carbon Permit Allocation

    Institute of Scientific and Technical Information of China (English)

    何建坤; 陈文颖; 滕飞; 刘滨

    2009-01-01

    Long-term climate change mitigation target would highly constrain global carbon emissions in future.Carbon permit allocation under the long-term mitigation target would impact development space for all countries,involving the fundamental interests.Some developed countries advocate the principle of per capita emission convergence while China and other developing countries propose the principle of convergence of accumulative emission per capita to consider historical responsibility.If the latter is used for carbon permit allocation,CO_2 emissions of developed countries since the industrial revolution have far exceeded their allocated permits.Developed countries'high per capita emissions at present and for quite a long period in future would continue to occupy emission spaces for developing countries.Therefore,developed countries must commit deeper emission reduction rate for the next commitment period at the Copenhagen conference in order to achieve the emission pathway under the long-term emission reduction target,and to save necessary development space for developing countries.At the same time,developed countries should provide adequate financial and technical suppoa as compensation for their overuse of the development space for developing countries,to improve developing countries'capacity to respond to climate change under the framework of sustainable development.On the one hand,we should insist on the principle of equity to obtain reasonable emission space for our country in the international climate change negotiation;while on the other hand,we should enhance development toward low-carbon economy to protect global environment and to achieve sustainable development.%全球长期减排目标将对世界未来的碳排放形成严重制约,减排义务的分担原则涉及各国的发展空间,事关根本利益.部分发达国家倡导人均排放趋同原则,回避发达国家的历史责任,中国等发展中国家提出人均累积排放趋同原则,强调公

  1. Targeting of Carbon Ion-Induced G2 Checkpoint Activation in Lung Cancer Cells Using Wee-1 Inhibitor MK-1775.

    Science.gov (United States)

    Ma, Hongyu; Takahashi, Akihisa; Sejimo, Yukihiko; Adachi, Akiko; Kubo, Nobuteru; Isono, Mayu; Yoshida, Yukari; Kanai, Tatsuaki; Ohno, Tatsuya; Nakano, Takashi

    2015-12-01

    The potent inhibitor of the cell cycle checkpoint regulatory factor Wee-1, MK-1775, has been reported to enhance non-small cell lung cancer (NSCLC) cell sensitivity to photon radiation by abrogating radiation-induced G2 arrest. However, little is known about the effects of this sensitizer after exposure to carbon (C)-ion radiation. The purpose of this study was therefore to investigate the effects of C ions in combination with MK-1775 on the killing of NSCLC cells. Human NSCLC H1299 cells were exposed to X rays or C ions (290 MeV/n, 50 keV/μm at the center of a 6 cm spread-out Bragg peak) in the presence of MK-1775. The cell cycle was analyzed using flow cytometry and Western blotting. Radiosensitivity was determined using clonogenic survival assays. The mechanisms underlying MK-1775 radiosensitization were studied by observing H2AX phosphorylation and mitotic catastrophe. G2 checkpoint arrest was enhanced 2.3-fold by C-ion exposure compared with X-ray exposure. Radiation-induced G2 checkpoint arrest was abrogated by MK-1775. Exposure to radiation resulted in a significant reduction in the mitotic ratio and increased phosphorylation of cyclin-dependent kinase 1 (Cdk1), the primary downstream mediator of Wee-1-induced G2 arrest. The Wee-1 inhibitor, MK-1775 restored the mitotic ratio and suppressed Cdk1 phosphorylation. In addition, MK-1775 increased H1299 cell sensitivity to C ions and X rays independent of TP53 status. MK-1775 also significantly increased H2AX phosphorylation and mitotic catastrophe in irradiated cells. These results suggest that the G2 checkpoint inhibitor MK-1775 can enhance the sensitivity of human NSCLC cells to C ions as well as X rays. PMID:26645158

  2. Accelerated killing of cancer cells using a multifunctional single-walled carbon nanotube-based system for targeted drug delivery in combination with photothermal therapy

    Directory of Open Access Journals (Sweden)

    Jeyamohan P

    2013-07-01

    Full Text Available Prashanti Jeyamohan, Takashi Hasumura, Yutaka Nagaoka, Yasuhiko Yoshida, Toru Maekawa, D Sakthi Kumar Bio-Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Japan Abstract: The photothermal effect of single-walled carbon nanotubes (SWCNTs in combination with the anticancer drug doxorubicin (DOX for targeting and accelerated destruction of breast cancer cells is demonstrated in this paper. A targeted drug-delivery system was developed for selective killing of breast cancer cells with polyethylene glycol biofunctionalized and DOX-loaded SWCNTs conjugated with folic acid. In our work, in vitro drug-release studies showed that the drug (DOX binds at physiological pH (pH 7.4 and is released only at a lower pH, ie, lysosomal pH (pH 4.0, which is the characteristic pH of the tumor environment. A sustained release of DOX from the SWCNTs was observed for a period of 3 days. SWCNTs have strong optical absorbance in the near-infrared (NIR region. In this special spectral window, biological systems are highly transparent. Our study reports that under laser irradiation at 800 nm, SWCNTs exhibited strong light–heat transfer characteristics. These optical properties of SWCNTs open the way for selective photothermal ablation in cancer therapy. It was also observed that internalization and uptake of folate-conjugated NTs into cancer cells was achieved by a receptor-mediated endocytosis mechanism. Results of the in vitro experiments show that laser was effective in destroying the cancer cells, while sparing the normal cells. When the above laser effect was combined with DOX-conjugated SWCNTs, we found enhanced and accelerated killing of breast cancer cells. Thus, this nanodrug-delivery system, consisting of laser, drug, and SWCNTs, looks to be a promising selective modality with high treatment efficacy and low side effects for cancer therapy. Keywords: cancer, nanotherapy, SWCNTs, targeted drug delivery

  3. Assessment of carbon allocation and biomass production in a natural stand of the salt marsh plant Spartina anglica using C- 13

    NARCIS (Netherlands)

    Hemminga, M.A.; Huiskes, A.H.L.; Steegstra, M.; Van Soelen, J.

    1996-01-01

    The proportional allocation of photosynthetically fixed carbon to the root and shoot system of salt marsh plants is an important element in the carbon cycle of tidal salt marshes. The commonly applied field methods giving insight on this point are based on successive harvesting of biomass. These met

  4. Partitioning Net Ecosystem Carbon Exchange Into net Assimilation and Respiration With Canopy-scale Isotopic Measurements: an Error Propagation Analysis With Both 13C and 18O Data

    Science.gov (United States)

    Peylin, P.; Ogee, J.; Cuntz, M.; Bariac, T.; Ciais, P.; Brunet, Y.

    2003-12-01

    Stable CO2 isotope measurements are increasingly used to partition the net CO2 exchange between terrestrial ecosystems and the atmosphere in terms of non-foliar respiration (FR) and gross photosynthesis (FA). However the accuracy of the partitioning strongly depends on the isotopic disequilibrium between these two gross fluxes and a rigorous estimation of the errors on FA and FR is needed. In this study we account and propagate uncertainties on all terms in the mass balance equations for total and "labeled" CO2 in order to get precise estimates of the errors on FA and FR. We applied our method to a maritime pine forest in the Southwest of France. Using the δ 13C-CO2 and CO2 measurements, we show that the resulting uncertainty associated to the gross fluxes can be as large as 4 æmol m-2 s-1. In addition, even if we could get more precise estimates of the isoflux and the isotopic signature of FA we show that this error would not be significantly reduced. This is because the isotopic disequilibrium between FA and FR is around 2-3‰ , i.e. the order of magnitude of the uncertainty on the isotopic signature of FR (δ R). With δ 18O-CO2 and CO2 measurements, the uncertainty associated to the gross fluxes lies also around 4 æmol m-2 s-1. On the other hand, it could be dramatically reduced if we were able to get more precise estimates of the CO18O isoflux and the associated discrimination during photosynthesis. This is because the isotopic disequilibrium between FA and FR is large, of the order of 10-15‰ , i.e. much larger than the uncertainty on δ R. The isotopic disequilibrium between FA and FR or the uncertainty on δ R vary among ecosystems and over the year. Our approach may help to choose the best strategy to study the carbon budget of a given ecosystem using stable isotopes.

  5. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to carbonate and bicarbonate salts of sodium and potassium and maintenance of normal bone (ID 331, 1402) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    claims in relation to carbonate and bicarbonate salts of sodium and potassium and maintenance of normal bone. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member....../base balance and bone health” and “bone density/bone health”. The target population is assumed to be the general population. In the context of the proposed wordings, the Panel assumes that the claimed effects refer to the maintenance of normal bone by maintaining acid-base balance. The Panel considers that...... maintenance of normal bone is a beneficial physiological effect. No references were provided from which conclusions could be drawn for the scientific substantiation of the claim. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the...

  6. NF-κB/AP-1-Targeted Inhibition of Macrophage-Mediated Inflammatory Responses by Depigmenting Compound AP736 Derived from Natural 1,3-Diphenylpropane Skeleton

    Directory of Open Access Journals (Sweden)

    Van Thai Ha

    2014-01-01

    Full Text Available AP736 was identified as an antimelanogenic drug that can be used for the prevention of melasma, freckles, and dark spots in skin by acting as a suppressor of melanin synthesis and tyrosinase expression. Since macrophage-mediated inflammatory responses are critical for skin health, here we investigated the potential anti-inflammatory activity of AP736. The effects of AP736 on various inflammatory events such as nitric oxide (NO/prostaglandin (PG E2 production, inflammatory gene expression, phagocytic uptake, and morphological changes were examined in RAW264.7 cells. AP736 was found to strongly inhibit the production of both NO and PGE2 in lipopolysaccharide- (LPS- treated RAW264.7 cells. In addition, AP736 strongly inhibited both LPS-induced morphological changes and FITC-dextran-induced phagocytic uptake. Furthermore, AP736 also downregulated the expression of multiple inflammatory genes, such as inducible NO synthase (iNOS, cyclooxygenase- (COX- 2, and interleukin- (IL- 1β in LPS-treated RAW264.7 cells. Transcription factor analysis, including upstream signalling events, revealed that both NF-κB and AP-1 were targeted by AP736 via inhibition of the IKK/IκBα and IRAK1/TAK1 pathways. Therefore, our results strongly suggest that AP736 is a potential anti-inflammatory drug due to its suppression of NF-κB-IKK/IκBα and AP-1-IRAK1/TAK1 signalling, which may make AP736 useful for the treatment of macrophage-mediated skin inflammation.

  7. Annual variation in δ13C values of maize and wheat: Effect on estimates of decadal scale soil carbon turnover

    DEFF Research Database (Denmark)

    Christensen, Bent Tolstrup; Olesen, Jørgen E; Hansen, Elly Møller;

    2011-01-01

    -derived soil C to be based on a fixed δ13C value. Further assumptions are that changes in the initial (time-zero) soil δ13C values are insignificant following conversion to C4-plants. We tested these assumptions by measuring: 1) the δ13C of annual samples of silage maize biomass (C4-plant) and winter......On sites where C4-plants have replaced C3-plants, changes in soil δ13C allow the turnover of C3- and C4-derived C to be separated. Studies of decadal scale turnover of soil C following conversion to C4-plants generally lack δ13C values for previous C4-residue inputs and assume that estimates of C4...... wheat grains (C3-plant) grown during 1988 to 2006, and 2) the δ13C of soil kept under bare fallow during 1956 to 1983. The δ13C of plants was related to climate variables, and the impact of maize δ13C was based on estimates of maize-derived soil C using different approaches to establish the δ13C...

  8. Effect of organic carbon chemistry on sorption of atrazine and metsulfuron-methyl as determined by (13)C-NMR and IR spectroscopy.

    Science.gov (United States)

    Dutta, Anirban; Mandal, Abhishek; Manna, Suman; Singh, S B; Berns, Anne E; Singh, Neera

    2015-10-01

    Soil organic matter (SOM) content is the major soil component affecting pesticide sorption. However, recent studies have highlighted the fact that it is not the total carbon content of the organic matter, but its chemical structure which have a profound effect on the pesticide's sorption. In the present study, sorption of atrazine and metsulfuron-methyl herbicides was studied in four SOM fractions viz. commercial humic acid, commercial lignin, as well as humic acid and humin extracted from a compost. Sorption data was fitted to the Freundlich adsorption equation. In general, the Freundlich slope (1/n) values for both the herbicides were herbicides, showed minimum desorption. Sorption of atrazine was best positively correlated with the alkyl carbon (adjusted R (2) = 0.748) and carbonyl carbon (adjusted R (2) = 0.498) but, their effect was statistically nonsignificant (P = 0.05). Metsulfuron-methyl sorption showed best positive correlation with carbonyl carbon (adjusted R (2) = 0.960; P = 0.05) content. Sorption of both the herbicides showed negative correlation with O/N-alkyl carbon. Correlation of herbicide's sorption with alkyl and carbonyl carbon content of SOM fractions suggested their contribution towards herbicide sorption. But, sorption of metsulfuron-methyl, relatively more polar than atrazine, was mainly governed by the polar groups in SOM. IR spectra showed that H-bonds and charge-transfer bonds between SOM fraction and herbicides probably operated as mechanisms of adsorption. PMID:26353968

  9. Carbon nanoparticles induce ceramide- and lipid raft-dependent signalling in lung epithelial cells: a target for a preventive strategy against environmentally-induced lung inflammation

    Directory of Open Access Journals (Sweden)

    Peuschel Henrike

    2012-12-01

    Full Text Available Abstract Background Particulate air pollution in lung epithelial cells induces pathogenic endpoints like proliferation, apoptosis, and pro-inflammatory reactions. The activation of the epidermal growth factor receptor (EGFR is a key event responsible for signalling events involving mitogen activated protein kinases specific for these endpoints. The molecular events leading to receptor activation however are not well understood. These events are relevant for the toxicological evaluation of inhalable particles as well as for potential preventive strategies in situations when particulate air pollution cannot be avoided. The current study therefore had the objective to elucidate membrane-coupled events leading to EGFR activation and the subsequent signalling cascade in lung epithelial cells. Furthermore, we aimed to identify the molecular target of ectoine, a biophysical active substance which we described to prevent carbon nanoparticle-induced lung inflammation. Methods Membrane signalling events were investigated in isolated lipid rafts from lung epithelial cells with regard to lipid and protein content of the signalling platforms. Using positive and negative intervention approaches, lipid raft changes, subsequent signalling events, and lung inflammation were investigated in vitro in lung epithelial cells (RLE-6TN and in vivo in exposed animals. Results Carbon nanoparticle treatment specifically led to an accumulation of ceramides in lipid rafts. Detailed analyses demonstrated a causal link of ceramides and subsequent EGFR activation coupled with a loss of the receptor in the lipid raft fractions. In vitro and in vivo investigations demonstrate the relevance of these events for carbon nanoparticle-induced lung inflammation. Moreover, the compatible solute ectoine was able to prevent ceramide-mediated EGFR phosphorylation and subsequent signalling as well as lung inflammation in vivo. Conclusion The data identify a so far unknown event in pro

  10. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Thomas C. Chidsey; Kevin McClure; Craig D. Morgan

    2003-10-05

    thickest part of the mound facies of the upper Ismay zone, where microporosity is well developed. In Bug field, the most productive wells are located structurally downdip from the updip porosity pinch out in the dolomitized lower Desert Creek zone, where micro-box-work porosity is well developed. Microporosity and micro-box-work porosity have the greatest hydrocarbon storage and flow capacity, and potential horizontal drilling target in these fields. Diagenesis is the main control on the quality of Ismay and Desert Creek reservoirs. Most of the carbonates present within the lower Desert Creek and Ismay have retained a marine-influenced carbon isotope geochemistry throughout marine cementation as well as through post-burial recycling of marine carbonate components during dolomitization, stylolitization, dissolution, and late cementation. Meteoric waters do not appear to have had any effect on the composition of the dolomites in these zones. Light oxygen values obtained from reservoir samples for wells located along the margins or flanks of Bug field may be indicative of exposure to higher temperatures, to fluids depleted in {sup 18}O relative to sea water, or to hypersaline waters during burial diagenesis. The samples from Bug field with the lightest oxygen isotope compositions are from wells that have produced significantly greater amounts of hydrocarbons. There is no significant difference between the oxygen isotope compositions from lower Desert Creek dolomite samples in Bug field and the upper Ismay limestones and dolomites from Cherokee field. Carbon isotopic compositions for samples from Patterson Canyon field can be divided into two populations: isotopically heavier mound cement and isotopically lighter oolite and banded cement. Technology transfer activities consisted of exhibiting a booth display of project materials at the annual national convention of the American Association of Petroleum Geologists, a technical presentation, a core workshop, and publications

  11. Integrated molecular targeting of IGF1R and HER2 surface receptors and destruction of breast cancer cells using single wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Shao Ning [Delaware MEMS and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 (United States); Lu Shaoxin [Delaware MEMS and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 (United States); Wickstrom, Eric [Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Panchapakesan, Balaji [Delaware MEMS and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 (United States)

    2007-08-08

    Molecular targeting and photodynamic therapy have shown great potential for selective cancer therapy. We hypothesized that monoclonal antibodies that are specific to the IGF1 receptor and HER2 cell surface antigens could be bound to single wall carbon nanotubes (SWCNT) in order to concentrate SWCNT on breast cancer cells for specific near-infrared phototherapy. SWCNT functionalized with HER2 and IGF1R specific antibodies showed selective attachment to breast cancer cells compared to SWCNT functionalized with non-specific antibodies. After the complexes were attached to specific cancer cells, SWCNT were excited by {approx}808 nm infrared photons at {approx}800 mW cm{sup -2} for 3 min. Viability after phototherapy was determined by Trypan blue exclusion. Cells incubated with SWCNT/non-specific antibody hybrids were still alive after photo-thermal treatment due to the lack of SWNT binding to the cell membrane. All cancerous cells treated with IGF1R and HER2 specific antibody/SWCNT hybrids and receiving infrared photons showed cell death after the laser excitation. Quantitative analysis demonstrated that all the cells treated with SWCNT/IGF1R and HER2 specific antibody complex were completely destroyed, while more than 80% of the cells with SWCNT/non-specific antibody hybrids remained alive. Following multi-component targeting of IGF1R and HER2 surface receptors, integrated photo-thermal therapy in breast cancer cells led to the complete destruction of cancer cells. Functionalizing SWCNT with antibodies in combination with their intrinsic optical properties can therefore lead to a new class of molecular delivery and cancer therapeutic systems.

  12. Large-angle production of charged pions by 3 GeV/c - 12 GeV/c protons on carbon, copper and tin targets

    CERN Document Server

    Catanesi, M G; Edgecock, R; Ellis, M; Robbins, S; Soler, F J P; Gössling, C; Bunyatov, S; Krasnoperov, A; Popov, B; Serdiouk, V; Tereschenko, V; Di Capua, E; Vidal-Sitjes, G; Artamonov, A; Arce, P; Giani, S; Gilardoni, S; Gorbunov, P; Grant, A; Grossheim, A; Gruber, P; Ivanchenko, V; Kayis-Topaksu, A; Panman, J; Papadopoulos, I; Pasternak, J; Chernyaev, E; Tsukerman, I; Veenhof, R; Wiebusch, C; Zucchelli, P; Blondel, A; Borghi, S; Campanelli, M; Morone, M C; Prior, G; Schroeter, R; Engel, R; Meurer, C; Kato, I; Gastaldi, Ugo; Mills, G B; Graulich, J S; Grégoire, G; Bonesini, M; Ferri, F; Paganoni, M; Paleari, F; Kirsanov, M; Bagulya, A; Grichine, V; Polukhina, N; Palladino, V; Coney, L; Schmitz, D; Barr, G; De Santo, A; Pattison, C; Zuber, K; Bobisut, F; Gibin, D; Guglielmi, A; Mezzetto, M; Dumarchez, J; Vannucci, F; Dore, U; Orestano, D; Pastore, F; Tonazzo, A; Tortora, L; Booth, C; Buttar, C; Hodgson, P; Howlett, L; Bogomilov, M; Chizhov, M; Kolev, D; Tsenov, R; Piperov, S; Temnikov, P; Apollonio, M; Chimenti, P; Giannini, G; Santin, G; Burguet-Castell, J; Cervera-Villanueva, A; Gómez-Cadenas, J J; Martín-Albo, J; Novella, P; Sorel, M; Tornero, A

    2008-01-01

    A measurement of the double-differential $\\pi^{\\pm}$ production cross-section in proton--carbon, proton--copper and proton--tin collisions in the range of pion momentum $100 \\MeVc \\leq p < 800 \\MeVc$ and angle $0.35 \\rad \\le \\theta <2.15 \\rad$ is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \\GeVc to 12 \\GeVc hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections at four incident proton beam momenta (3 \\GeVc, 5 \\GeVc, 8 \\GeVc and 12 \\GeVc).

  13. Large-angle production of charged pions by 3 GeV/c-12 GeV/c protons on carbon, copper and tin targets

    Science.gov (United States)

    Catanesi, M. G.; Radicioni, E.; Edgecock, R.; Ellis, M.; Robbins, S.; Soler, F. J. P.; Gößling, C.; Bunyatov, S.; Krasnoperov, A.; Popov, B.; Serdiouk, V.; Tereschenko, V.; di Capua, E.; Vidal-Sitjes, G.; Arce, P.; Artamonov, A.; Giani, S.; Gilardoni, S.; Gorbunov, P.; Grant, A.; Grossheim, A.; Gruber, P.; Ivanchenko, V.; Kayis-Topaksu, A.; Panman, J.; Papadopoulos, I.; Pasternak, J.; Tcherniaev, E.; Tsukerman, I.; Veenhof, R.; Wiebusch, C.; Zucchelli, P.; Blondel, A.; Borghi, S.; Campanelli, M.; Morone, M. C.; Prior, G.; Schroeter, R.; Engel, R.; Meurer, C.; Kato, I.; Gastaldi, U.; Mills, G. B.; Graulich, J. S.; Grégoire, G.; Kirsanov, M.; Bonesini, M.; Ferri, F.; Paganoni, M.; Paleari, F.; Bagulya, A.; Grichine, V.; Polukhina, N.; Palladino, V.; Coney, L.; Schmitz, D.; Barr, G.; de Santo, A.; Pattison, C.; Zuber, K.; Bobisut, F.; Gibin, D.; Guglielmi, A.; Mezzetto, M.; Dumarchez, J.; Vannucci, F.; Dore, U.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Booth, C.; Buttar, C.; Hodgson, P.; Howlett, L.; Bogomilov, M.; Chizhov, M.; Kolev, D.; Tsenov, R.; Piperov, S.; Temnikov, P.; Apollonio, M.; Chimenti, P.; Giannini, G.; Santin, G.; Burguet-Castell, J.; Cervera-Villanueva, A.; Gómez-Cadenas, J. J.; Martín-Albo, J.; Novella, P.; Sorel, M.; Tornero, A.

    2008-01-01

    A measurement of the double-differential π± production cross-section in proton-carbon, proton-copper and proton-tin collisions in the range of pion momentum 100 MeV/ c≤p<800 MeV/ c and angle 0.35 rad≤θ<2.15 rad is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/ c to 12 GeV/ c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections d2σ/dpdθ at four incident proton beam momenta (3 GeV/ c, 5 GeV/ c, 8 GeV/ c and 12 GeV/ c).

  14. (13)Carbon and (15)nitrogen isotopes in autopsy liver tissue samples from Greenlandic Inuit and Danes: consumption of marine versus terrestrial food

    DEFF Research Database (Denmark)

    Milman, N.; Laursen, J.; Mulvad, G.;

    2010-01-01

    . Results: Inuit: median delta C-13 was -21.2 parts per thousand in cellular and -20.0 parts per thousand in connective tissue fractions (P = 001). Median delta N-15 was 10.6 parts per thousand in both cellular and connective tissue fractions. Body mass index was negatively correlated with delta C-13...... in the connective tissue fraction (r(s) = -0.42, P = 0.057). Danes: median delta C-13 was -27.0% in cellular and -24.3% in connective tissue fractions (P = 0.11). Median delta N-15 was 9.5 parts per thousand in cellular and 8.9 parts per thousand in connective tissue fractions (P = 0.5). Inuit had higher delta C-13...

  15. Effect of organic carbon chemistry on sorption of atrazine and metsulfuron-methyl as determined by (13)C-NMR and IR spectroscopy.

    Science.gov (United States)

    Dutta, Anirban; Mandal, Abhishek; Manna, Suman; Singh, S B; Berns, Anne E; Singh, Neera

    2015-10-01

    Soil organic matter (SOM) content is the major soil component affecting pesticide sorption. However, recent studies have highlighted the fact that it is not the total carbon content of the organic matter, but its chemical structure which have a profound effect on the pesticide's sorption. In the present study, sorption of atrazine and metsulfuron-methyl herbicides was studied in four SOM fractions viz. commercial humic acid, commercial lignin, as well as humic acid and humin extracted from a compost. Sorption data was fitted to the Freundlich adsorption equation. In general, the Freundlich slope (1/n) values for both the herbicides were <1. Except for atrazine sorption on commercial humic acid, metsulfuron-methyl was more sorbed. Desorption results suggested that atrazine was more desorbed than metsulfuron-methyl. Lignin, which showed least sorption of both the herbicides, showed minimum desorption. Sorption of atrazine was best positively correlated with the alkyl carbon (adjusted R (2) = 0.748) and carbonyl carbon (adjusted R (2) = 0.498) but, their effect was statistically nonsignificant (P = 0.05). Metsulfuron-methyl sorption showed best positive correlation with carbonyl carbon (adjusted R (2) = 0.960; P = 0.05) content. Sorption of both the herbicides showed negative correlation with O/N-alkyl carbon. Correlation of herbicide's sorption with alkyl and carbonyl carbon content of SOM fractions suggested their contribution towards herbicide sorption. But, sorption of metsulfuron-methyl, relatively more polar than atrazine, was mainly governed by the polar groups in SOM. IR spectra showed that H-bonds and charge-transfer bonds between SOM fraction and herbicides probably operated as mechanisms of adsorption.

  16. Isotopic signatures (13C/12C; 15N/14N) of blue penguin burrow soil invertebrates : carbon sources and trophic relationships

    International Nuclear Information System (INIS)

    Seabird burrows provide a soil environment for processing discards such as feathers and guano, hence constituting a primary interface between the sea and the land. This study involved collection and culturing of soil invertebrates from three blue penguin (Eudyptula minor) burrows, and examined their 13C/12C and 15N/14N isotopic composition in relation to potential burrow resources (terrestrial plant litter, burrow soil, guano, blue penguin feathers). Two taxa (cerylonid beetles and small tineid moth larvae) had a depleted 13C/12C indicative of a level of dependence on C from terrestrial soil. Tineid moth larvae (Monopis crocicapitella and (or) M. ethelella) substantially increased their 13C/12C enrichment during development, implying increasing dependence on marine C. Remaining taxa, both decomposers and predators, had 13C/12C intermediate between guano and feathers. Larval and emergent fleas had the most enriched 13C/12C , indicative of a greater dependence on feather C and the likelihood of co-processing with guano. Pseudoscorpions and histerid beetles had overlapping isotopic enrichments implying competition for prey, but were spatially separated in burrow soil. With their highly enriched 15N/14N and marine 13C/12C, larvae and protonymphs of the histiostomatid mite Myianoetus antipodus stood alone. Blue penguin burrows therefore support a diverse invertebrate fauna that incorporates terrestrial soil as well as varying proportions of the various blue penguin discards. (author). 45 refs., 1 fig., 1 tab.

  17. The Basic Thoughts of Targeted Poverty Alleviation during the Period of 13th Five-Year%“十三五”时期精准扶贫的基本思路

    Institute of Scientific and Technical Information of China (English)

    马燕坤; 肖金成

    2016-01-01

    “十三五”将是我国扶贫减贫,消除贫困的攻坚克难决战期。“精准扶贫”是中共中央总书记、国家主席习近平同志提出的扶贫要求。精准扶贫与粗放扶贫、“一刀切”扶贫、“漫灌”式扶贫、盲目扶贫等相对而言。精准扶贫的基本出发点是“一方水土养一方人”,但是一方水土是否能够养得了其承载的一方人口,关键要看这一方水土的经济开发潜力,而不是看已经成为现实的经济开发强度。精准扶贫的基本思路一是从以县为单元扶贫变为扶贫到户;二是从开发式扶贫转为城镇化扶贫。精准扶贫的路径有转移就业扶贫、城市建设扶贫、生态搬迁扶贫、生态工程扶贫、教育观念扶贫、保障救助扶贫等。%It will be the tackle tough period of reducing poverty reduction and eliminating poverty during the period of 13th Five-Year in China. The targeted poverty alleviation is the requirement that the General Secretary of the Communist Party of China and the Chinese President Xi Jinping put forward. The targeted poverty alleviation is mentioned relative to extensive poverty alleviation, "one-size-fits-all" poverty alleviation, "flooding" poverty alleviation and blind poverty alleviation. The basic starting point of the targeted poverty alleviation is that different water and soil raised different people. But, the key issue that whether or not one side water and soil can support the population It bears is its economic developing potentiality rather than its existing economic developing strength. The basic thoughts of the targeted poverty alleviation are from taking counties as a unit for poverty alleviation to taking households as a unit for poverty alleviation and from development-oriented poverty alleviation to urbanization-oriented poverty alleviation. The paths of the Targeted poverty alleviation mainly include transferring employment, city construction, ecological relocation

  18. FINAL REPORT: A Study of the Abundance and 13C/12C Ratio of Atmospheric Carbon Dioxide to Advance the Scientific Understanding of Terrestrial Processes Regulating the GCC

    Energy Technology Data Exchange (ETDEWEB)

    Keeling, R. F.; Piper, S. C.

    2008-12-23

    The main objective of this project was to continue research to develop carbon cycle relationships related to the land biosphere based on remote measurements of atmospheric CO2 concentration and its isotopic composition. The project continued time-series observations of atmospheric carbon dioxide and isotopic composition begun by Charles D. Keeling at remote sites, including Mauna Loa, the South Pole, and eight other sites. The program also included the development of methods for measuring radiocarbon content in the collected CO2 samples and carrying out radiocarbon measurements in collaboration with Tom Guilderson of Lawrence Berkeley National Laboratory (LLNL). The radiocarbon measurements can provide complementary information on carbon exchange rates with the land and oceans and emissions from fossil-fuel burning. Using models of varying complexity, the concentration and isotopic measurements were used to establish estimates of the spatial and temporal variations in the net CO2 exchange with the atmosphere, the storage of carbon in the land and oceans, and variable isotopic discrimination of land plants.

  19. Stable isotope ratio (13C/12C mass spectrometry to evaluate carbon sources and sinks: changes and trends during the decomposition of vegetal debris from eucalyptus clone plantations (NW Spain

    Directory of Open Access Journals (Sweden)

    I. Fernandez

    2014-02-01

    Full Text Available Vegetal debris is known to participate in key soil processes such as the formation of soil organic matter (OM, also being a potential source of greenhouse gases to the atmosphere. However, its contribution to the isotopic composition of both the soil OM and the atmospheric carbon dioxide is not clear yet. Hence, the main objective of the present research is to understand the isotopic 13C changes and trends that take place during the successive biodegradative stages of decomposing soil organic inputs. By incubating bulk plant tissues for several months under laboratory controlled conditions, the kinetics of the CO2 releases and shifts in the 13C natural abundance of the solid residues were investigated using litter samples coming from forest plantations with a different clone (Anselmo: 1st clonal generation attained by morphological selection and Odiel: 2nd clonal generation genetically obtained of Eucalyptus globulus Labill. developed over granitic or schistic bedrocks and located in northwestern Spain. Significant isotopic variations with time were observed, probably due to the isotopically heterogeneous composition of these complex substrates in conjunction with the initial selective consumption of more easily degradable 13C-differentiated compounds during the first stages of the biodegradation, while less available or recalcitrant litter components were decomposed at later stages of biodegradation, generating products that have their own specific isotopic signatures. These results, which significantly differ depending on the type of clone, suggest that caution must be exercised when interpreting carbon isotope studies (at natural abundance levels since perturbations associated with the quality or chemical composition of the organic debris from different terrestrial ecosystems can have an important effect on the carbon stable isotope dynamics.

  20. 13C/Palynological evidence of differential residence times of organic carbon prior to its sedimentation in East African Rift Lakes and peat bogs

    Science.gov (United States)

    Hillaire-Marcel, Claude; Aucour, Anne-Marie; Bonnefille, Raymonde; Riollet, Guy; Vincens, Annie; Williamson, David

    Most terrestrial plants producing large amounts of organic matter in the East African Rift follow the Calvin (C3) photosynthetic pathway. Their end products have δ13C values of ca. -27 ± 2‰ (vs. PDB). On the contrary, most Cyperaceae (notably Cyperus papyrus and C. latifolius) are characterized by higher 13C contents ° 13C = -10.5 ± 1‰ ) in relation to their Hatch and Slack (C4) photosynthetic cycle. In consequence, δ13C values in total organic matter (TOM) from peat bog or lake cores essentially responded to the proportion of detritus from C4-Cyperaceae. Immediate evidence of the development or disappearance of Cyperaceae around lake margins or in peat bogs can be found in pollen assemblages. Lag times between pollen signals and correlative ° 13C shifts in TOM from cores are therefore indicative of the residence time of organic matter prior to its sedimentation. Delayed sedimentation of TOM will result in 14C anomalies which depend on several parameters, most of them being site specific as shown by examples from a peat bog in Burundi and from southern Lake Tanganyika. An independent assessment of the chronology by high resolution paleomagnetic correlations indicates a ca. 1.5 ka apparent 14C age of TOM in Lake Tanganyika at the Pleistocene-Holocene transition.

  1. Summary on Relationship Between Stable Carbon Isotope Composition of Plants and Soil Salinity%植物δ13C与土壤盐分的关系研究综述

    Institute of Scientific and Technical Information of China (English)

    王文文

    2012-01-01

    Stable carbon isotope composition (δ13C) can synthetically reflect the eco-physiological characteristics of plants, and be used to study the relationship between plant and ecological environment. Many studies reported that the change of δ13C value of plants was positively correlated with salinity. Soil salinity changed the 8 C value of C3 plants through affecting their physiological activities, such as stomatal conductance and photosynthesis. The high salinity-induced switch from C3-photosynthesis of some plants to Crassulacean Acid Metabolism or C4-photosynthesis adapted to the adverse environment and changed the δ13 C value of some plant organs, but the δ13C value of whole plants changed slightly. The relationship between 8 C and salinity was influenced by other environmental factors and limited conditions of laboratory experiments, thus it became necessary to broaden the range of salinity, extend the salt treatment time and carry out field experiment.%稳定碳同位素组成(δ13C)综合反映了植物的生理生态特征,可用于研究植物生理与生态环境之间的关系.大多数研究认为植物δ13C值随盐度增加而变重.盐分主要通过影响C3植物叶片气孔传导、光合作用等生理活动,使植物δ13C值发生变化.而有些植物为适应盐分胁迫可能发生光合途径的转换,使C3代谢转换成C4或CAM代谢,导致植物某些器官的δ13C值发生变化,而植株整体δ13C值变化较小.由于植物δ13C与土壤盐分的关系还受其他环境因素的影响以及室内试验的有限性,因此进一步扩大盐度梯度范围,延长盐处理时间以及开展大田试验显得很有必要.

  2. Stopping power of Ni, Ag, Au and Pb for approx. 7 MeV/n α-particles and carbon ions (Z13 proportional deviation from the Bethe formula)

    International Nuclear Information System (INIS)

    In the end of the 1960's, Andersen, Simonsen and Sorensen carried out the measurements of stopping powers of a number of elements for protons, deuterons and α-particles using the calorimetric-compensation technique and showed sone Z13 proportional deviations from the Bethe formula. Recently, Andersen and his co-workers again made the measurements of stopping power of several elements for protons, α-particles and lithium ions in order to perform a more detailed investigation on the deviation from the Bethe formula. To ascertain the Z13 deviation of stopping power for heavier ions, it is desirable to make precise experiments using projectiles more massive than lithium ions, which are almost completely ionized. Recently, we attempted to measure the stopping powers of several metals for approx. 7 MeV/n α-particles and carbon ions, although thus obtained data need a small correction for effective charge. Results are presented and discussed

  3. The potential of carbon-11 and fluorine-18 chemistry: illustration through the development of positron emission tomography radioligands targeting the translocator protein 18 kDa

    International Nuclear Information System (INIS)

    The TSPO (translocator protein), also known as the peripheral benzodiazepine receptor, is up-regulated in the brain of subjects suffering from neuro-degenerative disorders such as Alzheimer's, Parkinson's and Huntington's disease. Moreover, this overexpression has been proved to be linked to micro-glia activation making thus the TSPO a marker of choice of neuro-inflammatory processes and therefore a potential target for the development of radioligands for positron emission tomography imaging. The discovery of selective TSPO ligands and their labelling with the short-lived positron-emitter isotopes carbon-11 and fluorine-18 emerged in the mid-1980's with the preparation of the 3-iso-quinolinecarboxamide [11C]PK11195. To date, an impressive number of promising compounds - [11C]PK11195-challengers - have been developed; some radioligands - for example, [11C]PBR28, [11C]DPA-713, [18F]FEDAA1106 and [18F]DPA-714 - are currently used in clinical trials. As illustrated in this review, the methodologies applied for the preparation of these compounds remain mainly [11C]methylations using [11C]MeI or [11C]MeOTf and SN2- type nucleophilic aliphatic [18F]fluorinations - two processes illustrating the state-of-the-art arsenal of reactions that involves these two short-lived radioisotopes - but alternative processes, such as [11C]carbonylations using [11C]CO and [11C]COCl2 as well as SNAr-type nucleophilic [18F]fluorinations, have also been reported and as such, reviewed herein. (authors)

  4. Docetaxel-loaded single-wall carbon nanohorns using anti-VEGF antibody as a targeting agent: characterization, in vitro and in vivo antitumor activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Qian; Li, Nannan; Shu, Chang; Li, Ruixin; Ma, Xiaona; Li, Xuequan; Wang, Ran; Zhong, Wenying, E-mail: wyzhong@cpu.edu.cn [China Pharmaceutical University, Department of Analytical Chemistry (China)

    2015-05-15

    A novel antitumor drug delivery system, docetaxel (DTX)-loaded oxidized single-wall carbon nanohorns (oxSWNHs) with anti-VEGF monoclonal antibody (mAb) as a target agent was constructed. DTX was absorbed onto the oxSWNHs via the physical adsorption or π–π interaction. DSPE–PEG–COOH was non-covalently wrapped to the hydrophobic surface of oxSWNHs to improve its water solubility and biocompatibility. The mAb was bonded to the PEG through amide bond. The DTX@oxSWNHs-PEG-mAb (DDS) exhibited suitable particle size (191.2 ± 2.1 nm), good particle size distribution (PDI: 0.196), and negative zeta potential (−24.3 ± 0.85 mV). These features enhanced permeability and retention (EPR) effect and reduced the drug molecule uptake by the reticuloendothelial system. The in vitro drug release followed non-Fickian diffusion (n = 0.6857, R = 0.9924) with the cumulative release of DTX 59 ± 1.35 % at 72 h. Compared with free DTX, the DDS enhanced the cytotoxicity in MCF-7 cell lines in vitro efficiently (IC{sub 50}: 2.96 ± 0.6 μg/ml), and provided higher antitumor efficacy (TGI: 69.88 %) in vivo. The histological analysis indicated that the DDS had no significant side effect. Therefore, the new DDS is promising to attain higher pharmaceutical efficacy and lower side effects than free DTX for cancer therapy. The research demonstrated that DTX@oxSWNHs-PEG-mAb might have promising biomedical applications for future cancer therapy.

  5. Docetaxel-loaded single-wall carbon nanohorns using anti-VEGF antibody as a targeting agent: characterization, in vitro and in vivo antitumor activity

    International Nuclear Information System (INIS)

    A novel antitumor drug delivery system, docetaxel (DTX)-loaded oxidized single-wall carbon nanohorns (oxSWNHs) with anti-VEGF monoclonal antibody (mAb) as a target agent was constructed. DTX was absorbed onto the oxSWNHs via the physical adsorption or π–π interaction. DSPE–PEG–COOH was non-covalently wrapped to the hydrophobic surface of oxSWNHs to improve its water solubility and biocompatibility. The mAb was bonded to the PEG through amide bond. The DTX@oxSWNHs-PEG-mAb (DDS) exhibited suitable particle size (191.2 ± 2.1 nm), good particle size distribution (PDI: 0.196), and negative zeta potential (−24.3 ± 0.85 mV). These features enhanced permeability and retention (EPR) effect and reduced the drug molecule uptake by the reticuloendothelial system. The in vitro drug release followed non-Fickian diffusion (n = 0.6857, R = 0.9924) with the cumulative release of DTX 59 ± 1.35 % at 72 h. Compared with free DTX, the DDS enhanced the cytotoxicity in MCF-7 cell lines in vitro efficiently (IC50: 2.96 ± 0.6 μg/ml), and provided higher antitumor efficacy (TGI: 69.88 %) in vivo. The histological analysis indicated that the DDS had no significant side effect. Therefore, the new DDS is promising to attain higher pharmaceutical efficacy and lower side effects than free DTX for cancer therapy. The research demonstrated that DTX@oxSWNHs-PEG-mAb might have promising biomedical applications for future cancer therapy.

  6. Direct uptake of organic carbon by grass roots and allocation in leaves and phytoliths: 13C labeling evidence

    OpenAIRE

    Alexandre, A.; Balesdent, J.; P. Cazevieille; C. Chevassus-Rosset; Signoret, P; J.-C. Mazur; Harutyunyan, A.; E. Doelsch; Basile-Doelsch, I.; H. Miche; Santos, G. M.

    2015-01-01

    In the rhizosphere, the uptake of low molecular weight carbon (C) and nitrogen (N) by plant roots has been well documented. While organic N uptake relatively to total uptake is important, organic C uptake is supposed to be low relatively to the plant's C budget. Recently, radiocarbon analyses demonstrated that a fraction of C from the soil was occluded in amorphous silica micrometric particles that precipitate in plant cells (phytoliths). Here, we investigated whether and in...

  7. Chemical structures of swine-manure chars produced under different carbonization conditions investigated by advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy

    Science.gov (United States)

    Two types of swine manure chars, hydrothermally-produced hydrochar and slow-pyrolysis pyrochar, and their raw swine manure solid were characterized using advanced 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Compared with the parent raw swine manure, both hydrochars and pyrochar di...

  8. Cobalt(III) complexes of [3(5)]adamanzane, 1,5,9,13-tetraazabicyclo[7.7.3]nonadecane. Report of an inert, chelate hydrogen carbonate ion

    DEFF Research Database (Denmark)

    Broge, Louise; Søtofte, Inger; Olsen, Carl Erik;

    2001-01-01

    .H2O (3a). The coordination geometry around the cobalt(III) ion is a distorted octahedron with the inorganic ligands at cis-positions. Complex 2 is the second example of a cobalt(III) complex for which the X-ray structure,sfiows a chelate binding mode of the hydrogen carbonate entity. The pK(a) value...... of the [Co([3(5)]adz)(HCO3)](2+) ion (2) was determined spectrophotometrically to be 0.27 (25 degreesC, I = 5.0 M). The protonation appears to occur at the noncoordinated carbonyl oxygen atom of the carbonate group, with hydrogen bonding to the crystal water molecule. Evidence is presented for this oxygen......-atom as the site of protonation in solution as well. In 5.0 M CF3SO3H a slow reaction of the carbonate complex, quantitatively yielding the [Co([3(5)]adz)(H2O)(2)](3+) ion, was observed. k(obs) 7.9(1) x 10(-6) s(-1) at 25 degreesC....

  9. Carbon Isotope (d13C) in dissolved inorganic carbon and other physical and biogeochemical variables synthesized across the global ocean from February 17, 1991 to February 21, 2005 (NODC Accession 0110496)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Measurements of d13C in DIC were compiled mainly from WOCE and CLIVAR cruises. The dataset also contains other physical and biogeochemical variables.

  10. Laboratory measurement of the 2-centimeter, 2/11/-2/12/ transition of normal formaldehyde and its carbon-13 and oxygen-18 species.

    Science.gov (United States)

    Tucker, K. D.; Tomasevich, G. R.; Thaddeus, P.

    1972-01-01

    Beam-maser spectrometric measurements to an accuracy of about 100 Hz have been conducted of the 2(11)-2(12) transition for the isotopic species of greatest astronomical interest - i.e., H2CO, H2(13)CO, and H2C(18)O. The samples used were not isotopically enriched, monomeric formaldehyde vapors. For these species, all the coupling constants required to calculate the hyperfine structure of any rotational transition have been determined.

  11. Effects of Application of Straw on Organic Carbon in Brown Soil Aggregates by δ13C Method%δ13C法研究秸秆添加对棕壤团聚体有机碳的影响

    Institute of Scientific and Technical Information of China (English)

    顾鑫; 安婷婷; 李双异; 李慧; 汪景宽

    2014-01-01

    将稳定同位素碳(δ13C)标记的玉米秸秆添加入棕壤,在沈阳农业大学试验站进行田间原位培养,研究玉米秸秆添加对棕壤水稳性团聚体分布的影响,探索秸秆腐解过程中水稳性团聚体有机碳动态变化规律.结果表明:玉米秸秆添加不仅促进了棕壤>2 000 μm水稳性团聚体的形成,提高团聚体平均重量直径(MWD),而且显著提高各级团聚体有机碳含量,并随团聚体级别增大而增大.随着培养时间的延长,棕壤的团聚能力逐渐减弱,水稳性大团聚体破碎转变成微团聚体,MWD有所降低.大团聚体中总有机碳、新碳含量均呈下降趋势,微团聚体中总有机碳、新碳含量均呈上升趋势.棕壤总有机碳与团聚体有机碳呈显著的正相关关系(P<0.05).

  12. Trisomy 13

    Science.gov (United States)

    ... artery at birth. There are often signs of congenital heart disease , such as: Abnormal placement of the heart toward ... almost immediately. Most infants with trisomy 13 have congenital heart disease. Complications may include: Breathing difficulty or lack of ...

  13. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V John V. Vickers Cruise in the Pacific Ocean (WOCE Section P13, NOAA CGC92 Cruise, August 4 - October 21, 1992)

    Energy Technology Data Exchange (ETDEWEB)

    Kozyr, A.

    2001-01-11

    This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO{sub 2}) and total alkalinity (TALK) at hydrographic stations during the R/V John V. Vickers oceanographic cruise in the Pacific Ocean (Section P13). Conducted as part of the World Ocean Circulation Experiment (WOCE) and the National Oceanic and Atmospheric Administration's Climate and Global Change Program, the cruise began in Los Angeles, California, on August 4, 1992, with a transit line (Leg 0) to Dutch Harbor, Alaska. On August 16, the ship departed Dutch Harbor on Leg 1 of WOCE section P13. On September 15, the R/V John V. Vickers arrived in Kwajalein, Marshall Islands, for emergency repairs, and after 11 days in port departed for Leg 2 of Section P13 on September 26. The cruise ended on October 21 in Noumea, New Caledonia. Measurements made along WOCE Section P13 included pressure, temperature, salinity [measured by a conductivity, temperature, and depth sensor (CTD)], bottle salinity, bottle oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-11, CFC-12), TCO{sub 2} , and TALK. The TCO{sub 2} was measured by coulometry using a Single-Operator Multiparameter Metabolic Analyzer (SOMMA). The overall precision and accuracy of the analyses was {+-}2 {micro}mol/kg. Samples collected for TALK were measured by potentiometric titration; precision was {+-}2 {micro}mol/kg. The CO{sub 2} -related measurements aboard the R/V John V. Vickers were supported by the U.S. Department of Energy. The WOCE Section P13 data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. The NDP consists of two oceanographic data files, two FORTRAN 90 data-retrieval routine files, a documentation file, and this printed report, which describes the contents and format of all files as well as the procedures and methods used to obtain the data. Instructions on how to access the data are provided.

  14. Constraints on the factors controlling 13C-18O bond abundances in biologically precipitated carbonates from measurements of marine calcifiers cultured at variable temperature, pH, and salinity

    Science.gov (United States)

    Conchas, T. E.; Eagle, R.; Eiler, J. M.; Ries, J. B.; Freitas, P. S.; Hiebenthal, C.; Wanamaker, A. D.; Tripati, A. K.

    2012-12-01

    Marine mollusks and corals are widely used as archives of past climate change; oxygen isotopic composition (δ18O value) of their carbonate minerals is perhaps the most commonly used proxy to reconstruct paleoclimate from these marine calcifiers. However, oxygen isotope paleothermometry of mollusks and corals is complicated by non-equilibrium "vital effects" and variations in seawater pH changes, both of which influence the net fractionation of oxygen isotopes between carbonate and water. Carbonate "clumped isotope" thermometry is an emerging approach that potentially addresses these ambiguities. Here we report measurements of abundance of 13C-18O bonds (described by the measured parameter Δ47) in a variety of marine calcifiers cultured under controlled conditions. Previous studies on biologically precipitated samples such as foraminifera, coccoliths, and corals have shown that Δ47 values are related to calcification temperature with a relationship that is generally similar to inorganic carbonate. However, the influence of effects other than temperature has not been extensively studied and little work has been done to explore the potential for small non-equilibrium effects in cultured specimens that were grown under controlled conditions. In this study, we report δ18O and Δ47 measurements of mollusk specimens that were cultured at several temperatures ranging from 5 to 25°C, as well as different pH and salinity values. We also report data for other marine calcifiers including the temperate coral species Oculina arbuscula and the coralline red algae Neogoniolithon sp., that were cultured at a single temperature but variable pH.

  15. Partitioning net ecosystem carbon exchange into net assimilation and respiration using 13CO2 measurements: A cost-effective sampling strategy

    Science.gov (United States)

    OgéE, J.; Peylin, P.; Ciais, P.; Bariac, T.; Brunet, Y.; Berbigier, P.; Roche, C.; Richard, P.; Bardoux, G.; Bonnefond, J.-M.

    2003-06-01

    The current emphasis on global climate studies has led the scientific community to set up a number of sites for measuring the long-term biosphere-atmosphere net CO2 exchange (net ecosystem exchange, NEE). Partitioning this flux into its elementary components, net assimilation (FA), and respiration (FR), remains necessary in order to get a better understanding of biosphere functioning and design better surface exchange models. Noting that FR and FA have different isotopic signatures, we evaluate the potential of isotopic 13CO2 measurements in the air (combined with CO2 flux and concentration measurements) to partition NEE into FR and FA on a routine basis. The study is conducted at a temperate coniferous forest where intensive isotopic measurements in air, soil, and biomass were performed in summer 1997. The multilayer soil-vegetation-atmosphere transfer model MuSICA is adapted to compute 13CO2 flux and concentration profiles. Using MuSICA as a "perfect" simulator and taking advantage of the very dense spatiotemporal resolution of the isotopic data set (341 flasks over a 24-hour period) enable us to test each hypothesis and estimate the performance of the method. The partitioning works better in midafternoon when isotopic disequilibrium is strong. With only 15 flasks, i.e., two 13CO2 nighttime profiles (to estimate the isotopic signature of FR) and five daytime measurements (to perform the partitioning) we get mean daily estimates of FR and FA that agree with the model within 15-20%. However, knowledge of the mesophyll conductance seems crucial and may be a limitation to the method.

  16. Investigating the effects of perturbations to pgi and eno gene expression on central carbon metabolism in Escherichia coli using 13 C metabolic flux analysis

    Directory of Open Access Journals (Sweden)

    Usui Yuki

    2012-06-01

    Full Text Available Abstract Background It has long been recognized that analyzing the behaviour of the complex intracellular biological networks is important for breeding industrially useful microorganisms. However, because of the complexity of these biological networks, it is currently not possible to obtain all the desired microorganisms. In this study, we constructed a system for analyzing the effect of gene expression perturbations on the behavior of biological networks in Escherichia coli. Specifically, we utilized 13 C metabolic flux analysis (13 C-MFA to analyze the effect of perturbations to the expression levels of pgi and eno genes encoding phosphoglucose isomerase and enolase, respectively on metabolic fluxes. Results We constructed gene expression-controllable E. coli strains using a single-copy mini F plasmid. Using the pgi expression-controllable strain, we found that the specific growth rate correlated with the pgi expression level. 13 C-MFA of this strain revealed that the fluxes for the pentose phosphate pathway and Entner-Doudoroff pathway decreased, as the pgi expression lelvel increased. In addition, the glyoxylate shunt became active when the pgi expression level was almost zero. Moreover, the flux for the glyoxylate shunt increased when the pgi expression level decreased, but was significantly reduced in the pgi-knockout cells. Comparatively, eno expression could not be decreased compared to the parent strain, but we found that increased eno expression resulted in a decreased specific growth rate. 13 C-MFA revealed that the metabolic flux distribution was not altered by an increased eno expression level, but the overall metabolic activity of the central metabolism decreased. Furthermore, to evaluate the impact of perturbed expression of pgi and eno genes on changes in metabolic fluxes in E. coli quantitatively, metabolic sensitivity analysis was performed. As a result, the perturbed expression of pgi gene had a great impact to the

  17. Moss stable isotopes (carbon-13, oxygen-18) and testate amoebae reflect environmental inputs and microclimate along a latitudinal gradient on the Antarctic Peninsula.

    Science.gov (United States)

    Royles, Jessica; Amesbury, Matthew J; Roland, Thomas P; Jones, Glyn D; Convey, Peter; Griffiths, Howard; Hodgson, Dominic A; Charman, Dan J

    2016-07-01

    The stable isotope compositions of moss tissue water (δ(2)H and δ(18)O) and cellulose (δ(13)C and δ(18)O), and testate amoebae populations were sampled from 61 contemporary surface samples along a 600-km latitudinal gradient of the Antarctic Peninsula (AP) to provide a spatial record of environmental change. The isotopic composition of moss tissue water represented an annually integrated precipitation signal with the expected isotopic depletion with increasing latitude. There was a weak, but significant, relationship between cellulose δ(18)O and latitude, with predicted source water inputs isotopically enriched compared to measured precipitation. Cellulose δ(13)C values were dependent on moss species and water content, and may reflect site exposure to strong winds. Testate amoebae assemblages were characterised by low concentrations and taxonomic diversity, with Corythion dubium and Microcorycia radiata types the most cosmopolitan taxa. The similarity between the intra- and inter-site ranges measured in all proxies suggests that microclimate and micro-topographical conditions around the moss surface were important determinants of proxy values. Isotope and testate amoebae analyses have proven value as palaeoclimatic, temporal proxies of climate change, whereas this study demonstrates that variations in isotopic and amoeboid proxies between microsites can be beyond the bounds of the current spatial variability in AP climate. PMID:27003701

  18. Moss stable isotopes (carbon-13, oxygen-18) and testate amoebae reflect environmental inputs and microclimate along a latitudinal gradient on the Antarctic Peninsula.

    Science.gov (United States)

    Royles, Jessica; Amesbury, Matthew J; Roland, Thomas P; Jones, Glyn D; Convey, Peter; Griffiths, Howard; Hodgson, Dominic A; Charman, Dan J

    2016-07-01

    The stable isotope compositions of moss tissue water (δ(2)H and δ(18)O) and cellulose (δ(13)C and δ(18)O), and testate amoebae populations were sampled from 61 contemporary surface samples along a 600-km latitudinal gradient of the Antarctic Peninsula (AP) to provide a spatial record of environmental change. The isotopic composition of moss tissue water represented an annually integrated precipitation signal with the expected isotopic depletion with increasing latitude. There was a weak, but significant, relationship between cellulose δ(18)O and latitude, with predicted source water inputs isotopically enriched compared to measured precipitation. Cellulose δ(13)C values were dependent on moss species and water content, and may reflect site exposure to strong winds. Testate amoebae assemblages were characterised by low concentrations and taxonomic diversity, with Corythion dubium and Microcorycia radiata types the most cosmopolitan taxa. The similarity between the intra- and inter-site ranges measured in all proxies suggests that microclimate and micro-topographical conditions around the moss surface were important determinants of proxy values. Isotope and testate amoebae analyses have proven value as palaeoclimatic, temporal proxies of climate change, whereas this study demonstrates that variations in isotopic and amoeboid proxies between microsites can be beyond the bounds of the current spatial variability in AP climate.

  19. Characterization of high-tannin fractions from humus by carbon-13 cross-polarization and magic-angle spinning nuclear magnetic resonance.

    Science.gov (United States)

    Lorenz, Klaus; Preston, Caroline M

    2002-01-01

    Condensed tannins can be found in various parts of many plants. Unlike lignin there has been little study of their fate as they enter the soil organic matter pool and their influence on nutrient cycling, especially through their protein-binding properties. We extracted and characterized tannin-rich fractions from humus collected in 1998 from a black spruce [Picea mariana (Mill.) Britton et al.] forest in Canada where a previous study (1995) showed high levels (3.8% by weight) of condensed tannins. A reference tannin purified from black spruce needles was characterized by solution 13C nuclear magnetic resonance (NMR) as a pure procyanidin with mainly cis stereochemistry and an average chain length of four to five units. The colorimetric proanthocyanidin (PA) assay, standardized against the black spruce tannin, showed that both extracted humus fractions had higher tannin contents than the original humus (2.84% and 11.17% vs. 0.08%), and accounted for 32% of humus tannin content. Consistent with the results from the chemical assay, the aqueous fraction showed higher tannin signals in the 13C cross-polarization and magic-angle spinning (CPMAS) NMR spectrum than the emulsified one. As both tannin-rich humus fractions were depleted in N and high in structures derived from lignin and cutin, they did not have properties consistent with recaldtrant tannin-protein complexes proposed as a mechanism for N sequestration in humus. Further studies are needed to establish if tannin-protein structures in humus can be detected or isolated, or if tannins contribute to forest management problems observed in these ecosystems by binding to and slowing down the activity of soil enzymes.

  20. Solution (sup13)C Nuclear Magnetic Resonance Spectroscopic Analysis of the Amino Acids of Methanosphaera stadtmanae: Biosynthesis and Origin of One-Carbon Units from Acetate and Carbon Dioxide

    OpenAIRE

    Miller, T L; Chen, X; B. Yan; Bank, S.

    1995-01-01

    We found that general pathways for amino acid synthesis of Methanosphaera stadtmanae, a methanogen that forms CH(inf4) from H(inf2) and methanol, resembled those of methanogens that form CH(inf4) from CO(inf2) or from the methyl group of acetate. We determined the incorporation of (sup14)C-labeled CO(inf2), formate, methanol, methionine, serine, and acetate into cell macromolecules. Labeling of amino acid carbons was determined by solution nuclear magnetic resonance spectroscopy after growth ...