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Sample records for carbon 13 target

  1. Deep, noninvasive imaging and surgical guidance of submillimeter tumors using targeted M13-stabilized single-walled carbon nanotubes.

    Science.gov (United States)

    Ghosh, Debadyuti; Bagley, Alexander F; Na, Young Jeong; Birrer, Michael J; Bhatia, Sangeeta N; Belcher, Angela M

    2014-09-23

    Highly sensitive detection of small, deep tumors for early diagnosis and surgical interventions remains a challenge for conventional imaging modalities. Second-window near-infrared light (NIR2, 950-1,400 nm) is promising for in vivo fluorescence imaging due to deep tissue penetration and low tissue autofluorescence. With their intrinsic fluorescence in the NIR2 regime and lack of photobleaching, single-walled carbon nanotubes (SWNTs) are potentially attractive contrast agents to detect tumors. Here, targeted M13 virus-stabilized SWNTs are used to visualize deep, disseminated tumors in vivo. This targeted nanoprobe, which uses M13 to stably display both tumor-targeting peptides and an SWNT imaging probe, demonstrates excellent tumor-to-background uptake and exhibits higher signal-to-noise performance compared with visible and near-infrared (NIR1) dyes for delineating tumor nodules. Detection and excision of tumors by a gynecological surgeon improved with SWNT image guidance and led to the identification of submillimeter tumors. Collectively, these findings demonstrate the promise of targeted SWNT nanoprobes for noninvasive disease monitoring and guided surgery. PMID:25214538

  2. LAMPF polarized 13C targets

    International Nuclear Information System (INIS)

    Ethylene glycol, 1-butanol, and toluene highly enriched in 13C have been used at LAMPF to produce dynamically polarized 13C targets for scattering experiments with protons and pions. Preparation of the materials and characteristic properties of these targets are described. 17 refs., 1 fig

  3. 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

  4. Geometric effects on carbon-13 chemical shifts

    International Nuclear Information System (INIS)

    In the course of our investigations on carbon-13 chemical shifts of tetracyclic dodecanes, we managed to show that a large number of chemical shift differences between members of the series and models provided by bicyclic analogs could be attributed to steric effects. There are examples, however, where this is clearly not the case. In order to investigate apparent anomalies we calculated structures of interest and looked into the relationships between molecular geometry and chemical shifts. As the assignment of some of the key structures in these analysis were made by comparison with model compounds and crucial experiments that could remove ambiguities were missing, we prepared and interpreted two spectra which are presented

  5. Thick backed carbon targets via mechanical rolling

    International Nuclear Information System (INIS)

    For targets requiring thick backing foils, the straight-forward and usual method is to deposit the target material directly on the backing by thermal evaporation. In some instances the reverse is more desirable, adding a backing to an already existing target foil, for example. A recent study involving measurement of the lifetime of the first 2+ excited state in 36Ar by the Doppler shift attenuation method required 0.5 mg/cm2 natural carbon targets on thick (18 mg/cm2) gold and lead backings. Problems of delamination had arisen after beam irradiation using thick gold backings for these experiments. Carbon target foils were then prepared by mechanical rolling in direct contact with a thick lead backing using an intermediate layer of indium to assure good adhesion of the layers. Details of the method will be discussed. (author)

  6. 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

  7. 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

  8. 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.

  9. On the Chinese Carbon Reduction Target

    Directory of Open Access Journals (Sweden)

    Michinori Uwasu

    2010-06-01

    Full Text Available In November 2009, China pledged a 40–45% decrease in CO2 emissions per GDP by 2020, as compared with the 2005 level. Although carbon intensity (emission targets by nature are ambiguous, this study demonstrates that China’s pledge is consistent with the current Chinese domestic agenda that simultaneously pursues economic growth and energy security. The target numbers in the pledge seem reasonable, given the technological feasibility and measures, considered along with the assumption that moderate economic growth will occur. However, the study also argues that financial and institutional constraints exist as potential obstacles to achieving the target if the trend of the current economic tendencies continues.

  10. 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

  11. 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.

  12. 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.

  13. Suitable activated carbon-13 tracer techniques

    International Nuclear Information System (INIS)

    Feasibility and applicability studies of the proton induced gamma ray emission (PIGE) have been performed. The graphite was firstly bombarded at various proton energies to determine gamma ray yield (and, thus, sensitivities) for the reaction of interest. The accuracy for the determination of 13C abundance was checked, and the precision with which this value and ratios 13C/12C may be obtained was established by repetitive analysis samples. The performance of different standards in this determination was assessed. The mathematical treatment was developed for the determination of 13C abundance in tracer studies, and to derive the equations that govern this method of analysis from first principles, to arrive finally at a simple expression by virtue of the observed regularities. The system was calibrated by measuring the gamma ray yield form the 12C (p, γ)13N and 13C(p,γ)14N reaction as a function of known 13C enrichment. Using this experimentally determined calibration curve, unknown materials can be assayed. This technique is applicable to the analysis of samples with 13C enrichments between 0.1% and 90%. The samples of human breath natural samples were analyzed against graphite and Cylinder CO2 standards. Relative standard deviations were 13C abundance, an increase in 13C per cent isotopic abundance from the natural 1.11% (average) to only 1.39% may be ascertained. Finally, PIGE is compared with more classical techniques for analysis of 13C tracer experiments. Ease and speed are important advantages of this technique over mass spectrometry, and its error is compatible with the natural variation of biological results. (9 refs., 11 figs., 9 tabs.)

  14. 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...

  15. 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

  16. 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

  17. 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.

  18. 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

  19. Soil carbon inventories and carbon-13 on a latitude transect in Siberia

    Czech Academy of Sciences Publication Activity Database

    Bird, M. I.; Šantrůčková, Hana; Arneth, A.; Grigoriev, S.; Gleixner, G.; Kalaschnikov, Y. N.; Lloyd, J.; Schulze, E. D.

    2002-01-01

    Roč. 5, 54B (2002), s. 631-641. ISSN 0280-6509 Institutional research plan: CEZ:AV0Z6066911 Keywords : soil carbon inventories * carbon-13 * Siberia Subject RIV: EH - Ecology, Behaviour Impact factor: 3.196, year: 2002

  20. PEDOGENIC CARBONATE δ13C AND ENVIRONMENTAL PRECIPITATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    Marcella Catoni

    2011-12-01

    Full Text Available Carbon isotopic analysis is a useful tool for investigating paleoenvironments, as the pedogenic carbonate δ13C is related to δ13CSOM and to the proportions of C3/C4 plants. In this work we interpreted the paleoenvironmental conditions at the time of carbonate precipitation in soils formed under different climates and during different geological ages. Samples were taken from a Bk (PR1, Holocene and from two Bkm horizons (PR2 and PR3, Pleistocene. When the mean δ13C plant values and the most plausible paleotemperatures were used in the evaluation, PR1 showed a lower percentage of C4 plants (48% than Pleistocene soils (~53%, in agreement with paleoclimate changes. When instead the δ13C values of current plants were used for PR1, C4 plants ranged from 59 (12°C to 66% (18°C, suggesting two possible interpretations: either plant species changed during the Holocene, or the plant mean values normally used in the literature are not suitable for Pleistocene reconstructions

  1. Carbon-13 NMR characterization of actinyl(VI) carbonate complexes in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D.L.; Hobart, D.E.; Palmer, P.D. [Los Alamos National Lab., NM (United States); Sullivan, J.C. [Argonne National Lab., IL (United States); Stout, B.E. [Cincinnati Univ., OH (United States). Dept. of Chemistry

    1992-07-01

    The uranyl(VI) carbonate system has been re-examined using {sup 13}C NMR of 99.9% {sup 13}C-enriched U{sup VI}O{sub 2} ({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} in millimolar concentrations. By careful control of carbonate ion concentration, we have confirmed the existence of the trimer, and observed dynamic equilibrium between the monomer and the timer. In addition, the ligand exchange reaction between free and coordinated carbonate on Pu{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} and Am{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} systems has been examined by variable temperature {sup 13}C NMR line-broadening techniques {sup 13}C NMR line-broadening techniques. A modified Carr-Purcell-Meiboom-Gill NMR pulse sequence was written to allow for experimental determination of ligand exchange parameters for paramagnetic actinide complexes. Preliminary Eyring analysis has provided activation parameters of {Delta}G{sup {double_dagger}}{sub 295} = 56 kJ/M, {Delta}H{sup {double_dagger}} = 38 kJ/M, and {Delta}S{sup {double_dagger}} = {minus}60 J/M-K for the plutonyl triscarbonate system, suggesting an associative transition state for the plutonyl (VI) carbonate complex self-exchange reaction. Experiments for determination of the activation parameters for the americium (VI) carbonate system are in progress.

  2. Production of carbon-13-labeled cadaverine by engineered Corynebacterium glutamicum using carbon-13-labeled methanol as co-substrate.

    Science.gov (United States)

    Leßmeier, Lennart; Pfeifenschneider, Johannes; Carnicer, Marc; Heux, Stephanie; Portais, Jean-Charles; Wendisch, Volker F

    2015-12-01

    Methanol, a one-carbon compound, can be utilized by a variety of bacteria and other organisms as carbon and energy source and is regarded as a promising substrate for biotechnological production. In this study, a strain of non-methylotrophic Corynebacterium glutamicum, which was able to produce the polyamide building block cadaverine as non-native product, was engineered for co-utilization of methanol. Expression of the gene encoding NAD+-dependent methanol dehydrogenase (Mdh) from the natural methylotroph Bacillus methanolicus increased methanol oxidation. Deletion of the endogenous aldehyde dehydrogenase genes ald and fadH prevented methanol oxidation to carbon dioxide and formaldehyde detoxification via the linear formaldehyde dissimilation pathway. Heterologous expression of genes for the key enzymes hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase of the ribulose monophosphate (RuMP) pathway in this strain restored growth in the presence of methanol or formaldehyde, which suggested efficient formaldehyde detoxification involving RuMP key enzymes. While growth with methanol as sole carbon source was not observed, the fate of 13C-methanol added as co-substrate to sugars was followed and the isotopologue distribution indicated incorporation into central metabolites and in vivo activity of the RuMP pathway. In addition, 13C-label from methanol was traced to the secreted product cadaverine. Thus, this synthetic biology approach led to a C. glutamicum strain that converted the non-natural carbon substrate methanol at least partially to the non-native product cadaverine. PMID:26276544

  3. 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)

  4. 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.

  5. Fabrication of multilayer graded density carbon aerogel target

    International Nuclear Information System (INIS)

    The multilayer graded density carbon aerogel target was fabricated, which is considered to be an excellent unique target for ICF experiments and shock wave research. By polymerization reaction of resorcinol and formaldehyde and via a self-made flexible mould, a series of carbon aerogel unit sheets were obtained. Their thickness ranges from 100 to 580 μm and density ranges from 50 to 400 mg·cm-3. With low density(10 mg·cm-3) SiO2 aerogel as the bonding agent, a 5-layer graded density carbon aerogel target was fabricated. This work was focused on the microstructure of C/SiO2 aerogel interface. Scanning electron microscopy, X-ray phase contrast imaging method were used to observe the monolithic structure of the multilayer target and characterize the surface and internal microstructure of its unit sheets. The results show that the thickness of the bonding agent is approximately 15 μm, far less than that of carbon aerogel sheets. In addition, the C/SiO2 aerogel interface is smooth, and the formation of the target is homogeneous. (authors)

  6. 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).

  7. Measurement of carbon-13:carbon-12 ratios by Fourier transform infrared spectrometry

    International Nuclear Information System (INIS)

    An approach to the measurement of 13C:12C ratios in isotopically enriched samples is described. The carbon in samples is converted into CO2 gas by either combustion of organic material or acidification of carbonate. The gas is then measured by FTIR spectrometry. When spectra are recorded at 0.25 cm-1 resolution the magnitude of the isotopic shift is such that the areas of 12C and 13C rotational lines of the ν3 vibrational band for CO2 can be measured and the isotopic composition determined by reference to a standard calibration graph. The relative standard deviation at natural abundance is 1.2%, which gives an absolute limit of detection of 0.026 atom-% 13C. Details of the decomposition procedures and a comparison of the results with those obtained by mass spectrometry are also presented. (author)

  8. 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

  9. Fabrication of multilayer graded density peeled-carbon-aerogel target

    International Nuclear Information System (INIS)

    Research highlights: → 5-Layer graded density (50-400 mg cm-3) carbon aerogel target was fabrication. → Ultra-low density (10 mg cm-3) SiO2 aerogel as a bonding agent. → Thickness of each unit sheet ranged from 100 to 580 μm. → Several surface micro-treatments were used to peel off the 150 nm dense layer. → As a potential target for shock wave experiments. -- Abstract: As a potential target for shock wave experiments, the multilayer graded density carbon aerogel target was prepared. Firstly, carbon aerogel sheets with varying thickness and density were fabricated by polycondensation of resorcinol with formaldehyde by a self-made flexible micro-mould. Secondly, with ultra-low density (10 mg cm-3) SiO2 aerogel as a bonding agent, a 5-layer graded density carbon aerogel target was obtained. The thickness of each unit sheet ranged from 100 to 580 μm, and the density ranged from 50 to 400 mg cm-3. We focused on fabrication of unit sheets, peeling off their dense layers (about 150 nm) and research of C/SiO2 aerogel interface microstructure. Field emission scanning electron microscopy (FESEM), X-ray phase contrast imager and surface profiler were used to observe the multilayer structure and characterize the surface and internal microstructure of unit sheets. The results showed that the target fabricated by such method possessed multilayer graded density structure with homogeneous C/SiO2 interface and excellent formability.

  10. 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)

  11. 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.

  12. 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

  13. Carbon-13 kinetic isotope effects in CO oxidation by Ag

    International Nuclear Information System (INIS)

    In the catalytic oxidation of carbon monoxide over silver wool the 13C kinetic isotope effects in the 343--453 K temperature range were experimentally determined and the following temperature dependence was found: 100 ln(k12/k13) = (3.398--630/T) ± 0.083. A reaction CO/O2gas mixture of 1:2 ratio was used in a static system with initial pressures ranging from 20 to 40 kPa. Under these conditions the reaction is of order 1 with respect to CO and order 0 with respect to O2 and CO2 pressure. The apparent activation energy is 59.3 ± 1.7 kJ/mol. In the authors theoretical interpretation of the experimental data various geometries of (CO2)* and (CO3)* transition states were applied, and only a (CO2)* with an interbond angle of 110degree and CO stretching force constants of 1,700 and 1,000--1,400 N/m, respectively, with an asymmetric reaction coordinate was found to be acceptable

  14. 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.

  15. Carbon dynamics in corn-soybean sequences as estimated from natural carbon-13 abundance

    International Nuclear Information System (INIS)

    Carbon flow in terrestrial ecosystems regulates partitioning between soil organic C (SOC) and atmospheric CO2. Our objectives were to assess SOC dynamics using natural 13C abundance in corn (Zea mays L., a C4 species)-soybean [Glycine max (L.) Merr., a C3 species] sequences. Fifteen treatments of continuous corn, continuous soybean, various sequences of corn and soybean, and fallow were initiated in 1981 at Lamberton, MN, on a Webster clay loam (fine-loamy, mixed, mesic Typic Haplaquoll). In 1991, soil and aboveground shoot samples from all treatments were analyzed for total organic C and delta 13C. Carbon inputs, delta 13C, and SOC were integrated into a two-pool model to evaluate C dynamics of corn and soybean. Total SOC was similar across all treatments after 10 yr; however, differences in soil delta 13C occurred between continuous corn (delta 13C = -17.2 per thous and) and continuous soybean (delta 13C = -18.2 per thousand). Modeled C dynamics showed SOC decay rates of 0.011 yr-1 for C4-derived C and 0.007 yr-1 for C3-derived C, and humification rates of 0.16 yr-1 for corn and 0.11 yr-1 for soybean. Decay and humification rates were slightly lower than those found in other Corn Belt studies. Levels of SOC were predicted to decline an additional 7 to 18% with current C inputs from either corn or soybean, respectively. Annual C additions required for SOC maintenance averaged 5.6 Mg C ha-1, 1.4 to 2.1 times greater than previously reported estimates. Controlled variation in natural 13C abundance in corn-soybean rotations during a 10-yr period adequately traced C dynamics

  16. A tritium gas target for neutron production at HI-13 tandem accelerator

    International Nuclear Information System (INIS)

    A tritium gas target was built and employed in neutron physics experiment at HI-13 tandem accelerator. The gas target consists of a helium gas cell and a tritium gas cell. The entrance foils are 10 μm thick molybdenum ones. The target is intended as a neutron source using T(d,n)4He and T(p,n)3He reactions. Details of the target design and performance are given

  17. A tritium gas target for neutron production at HI-13 tandem accelerator

    International Nuclear Information System (INIS)

    A tritium gas target has been built and employed in neutron physics experiments at HI-13 tandem accelerator. The gas target consists of a helium gas cell and a tritium gas cell. The entrance foils are 10 μm thick molybdenum ones. The target is intended as a neutron source using T(d,n)4He and T(p,n)3He reactions. Details of the target design and performance are given

  18. Anti-tumor targeted drug delivery systems mediated by aminopeptidase N/CD13

    Directory of Open Access Journals (Sweden)

    Xun Wang

    2011-08-01

    Full Text Available Aminopeptidase N (APN/CD13 is a transmembrane glycoprotein, which is overexpressed on tumor neovascular endothelial cells and most tumor cells, where it plays an important role in tumor angiogenesis. Peptides containing the Asn-Gly-Arg (NGR motif can specifically recognize APN/CD13 allowing them to act as tumor-homing peptides for the targeted delivery of anti-tumor drugs to tumor neovascular endothelial cells and tumor cells. This article reviews the literature and recent developments related to APN/CD13, its role in tumor growth and some anti-tumor drug delivery systems containing NGR peptides designed to target APN/CD13.

  19. 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

  20. 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

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

    Science.gov (United States)

    Moon, Byung Seok; Lee, Hong Jin; Lee, Won Kyung; Hur, Min Goo; Yang, Seung Dae; Lee, Byung Chul; Kim, Sang Eun

    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 [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

  2. 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

  3. 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.

  4. 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

  5. Carbon nanotubes: an emerging drug carrier for targeting cancer cells.

    Science.gov (United States)

    Rastogi, Vaibhav; Yadav, Pragya; Bhattacharya, Shiv Sankar; Mishra, Arun Kumar; Verma, Navneet; Verma, Anurag; Pandit, Jayanta Kumar

    2014-01-01

    During recent years carbon nanotubes (CNTs) have been attracted by many researchers as a drug delivery carrier. CNTs are the third allotropic form of carbon-fullerenes which were rolled into cylindrical tubes. To be integrated into the biological systems, CNTs can be chemically modified or functionalised with therapeutically active molecules by forming stable covalent bonds or supramolecular assemblies based on noncovalent interactions. Owing to their high carrying capacity, biocompatibility, and specificity to cells, various cancer cells have been explored with CNTs for evaluation of pharmacokinetic parameters, cell viability, cytotoxicty, and drug delivery in tumor cells. This review attempts to highlight all aspects of CNTs which render them as an effective anticancer drug carrier and imaging agent. Also the potential application of CNT in targeting metastatic cancer cells by entrapping biomolecules and anticancer drugs has been covered in this review. PMID:24872894

  6. 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

  7. Bacterial carbonic anhydrases as drug targets: towards novel antibiotics ?

    Directory of Open Access Journals (Sweden)

    ClaudiuT.Supuran

    2011-07-01

    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 a-, b-, and/or g-CA families. In the last decade, the a-CAs from Neisseria spp. and Helicobacter pylori as well as the b-class enzymes from Escherichia coli, H. pylori, Mycobacterium tuberculosis, Brucella spp., Streptococcus pneumoniae, Salmonella enterica and Haemophilus influenzae have been cloned and characterized in detail. For some of these enzymes the X-ray crystal structures were determined, and in vitro and in vivo inhibition studies with various classes of inhibitors, such as anions, sulfonamides and sulfamates reported. Although efficient inhibitors have been reported for many such enzymes, only for Nessseria spp., H. pylori, B. suis and S. pneumoniae enzymes it has been possible to evidence inhibition of bacterial growth in vivo. Thus, bacterial CAs represent promising targets for obtaining antibacterials devoid of the resistance problems of the clinically used such agents but further studies are needed to validate these and other less investigated enzymes as novel drug targets

  8. 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

  9. 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...

  10. Improved cycling and high rate performance of core-shell LiFe1/3Mn1/3Co1/3PO4/carbon nanocomposites for lithium-ion batteries: Effect of the carbon source

    International Nuclear Information System (INIS)

    Highlights: • We report a fast microwave heating way to prepare LiFe1/3Mn1/3Co1/3PO4/C. • The effects of different carbon sources were discussed in detail. • LiFe1/3Mn1/3Co1/3PO4/BP2000 shows a discharge capacity of 160 mA h g−1 at 0.1 C. • LiFe1/3Mn1/3Co1/3PO4/BP2000 elucidates excellent cyclic stability. • LiFe1/3Mn1/3Co1/3PO4/BP2000 exhibits attractive rate capability. - Abstract: Core-shell type olivine solid solutions, LiFe1/3Mn1/3Co1/3PO4/C, are synthesized via a very simple and rapid microwave heating route with different carbon sources. The obatined LiFe1/3Mn1/3Co1/3PO4/C materials are characterized thoroughly by various analytical techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy-dispersive spectroscopy instrument. The particle sizes and distribution of the carbon layer of BP2000 carbon black coated LiFe1/3Mn1/3Co1/3PO4 (LiFe1/3Mn1/3Co1/3PO4/BP) are more uniform than that obtained from acetylene black (LiFe1/3Mn1/3Co1/3PO4/AB) and Super P (LiFe1/3Mn1/3Co1/3PO4/SP). Moreover, the LiFe1/3Mn1/3Co1/3PO4/BP nanocomposite shows superior electrochemical properties such as high discharge capacity of 160 mA h g−1 at 0.1 C, excellent cyclic stability (143 mA h g−1 at 0.1 C after 30 cycles) and rate capability (76 mAh g−1 at 20 C), which are better than other two samples. Cyclic voltammetric and electrical tests disclose that the Li-ion diffusion, the reversibility of lithium extraction/insertion and electrical conductivity are significantly improved in LiFe1/3Mn1/3Co1/3PO4/BP composite. Electrochemical impedance spectroscopy illustrates that LiFe1/3Mn1/3Co1/3PO4/BP composite electrode possesses low contact and charge-transfer impedances, which can lead to rapid electron transport during the electrochemical lithium insertion/extraction reaction. It is believed that olivine solid solution LiFe1/3Mn1/3Co1/3PO4 decorated with carbon from appropriate carbon source is a promising cathode for

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

    International Nuclear Information System (INIS)

    Cross sections for the /sup 13,14/C,26Mg,56Fe(π+,π-)/sup 13,14/O,26Si,56Ni 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 π/ 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 14O(0+, 5.92 MeV), 14O(2+, 7.77 MeV), 56Ni(gs), 13O(gs), and 13O(4.21 MeV) are presented. The 13O(4.21 MeV) state is postulated to have J/sup π/ = 1/2-. 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 Δ33 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 π/ > 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

  12. 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...

  13. Anti-tumor targeted drug delivery systems mediated by aminopeptidase N/CD13

    OpenAIRE

    Xun Wang; Bin Wang; Qiang Zhang

    2011-01-01

    Aminopeptidase N (APN)/CD13 is a transmembrane glycoprotein, which is overexpressed on tumor neovascular endothelial cells and most tumor cells, where it plays an important role in tumor angiogenesis. Peptides containing the Asn-Gly-Arg (NGR) motif can specifically recognize APN/CD13 allowing them to act as tumor-homing peptides for the targeted delivery of anti-tumor drugs to tumor neovascular endothelial cells and tumor cells. This article reviews the literature and recent developments rela...

  14. 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)

  15. Sc3CH@C80: selective (13)C enrichment of the central carbon atom.

    Science.gov (United States)

    Junghans, Katrin; Rosenkranz, Marco; Popov, Alexey A

    2016-05-01

    Sc3CH@C80 is synthesized and characterized by (1)H, (13)C, and (45)Sc NMR. A large negative chemical shift of the proton, -11.73 ppm in the Ih and -8.79 ppm in the D5h C80 cage isomers, is found. (13)C satellites in the (1)H NMR spectrum enabled indirect determination of the (13)C chemical shift for the central carbon at 173 ± 1 ppm. Intensity of the satellites allowed determination of the (13)C content for the central carbon atom. This unique possibility is applied to analyze the cluster/cage (13)C distribution in mechanistic studies employing either (13)CH4 or (13)C powder to enrich Sc3CH@C80 with (13)C. PMID:27109443

  16. 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)

  17. 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

  18. 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

  19. 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.

  20. 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

  1. The $^{13}$Carbon footprint of B[e] supergiants

    CERN Document Server

    Liermann, A; Schnurr, O; Fernandes, M Borges

    2010-01-01

    We report on the first detection of $^{13}$C enhancement in two B[e] supergiants in the Large Magellanic Cloud. Stellar evolution models predict the surface abundance in $^{13}$C to strongly increase during main-sequence and post-main sequence evolution of massive stars. However, direct identification of chemically processed material on the surface of B[e] supergiants is hampered by their dense, disk-forming winds, hiding the stars. Recent theoretical computations predict the detectability of enhanced $^{13}$C via the molecular emission in $^{13}$CO arising in the circumstellar disks of B[e] supergiants. To test this potential method and to unambiguously identify a post-main sequence B[e]SG by its $^{13}$CO emission, we have obtained high-quality $K$-band spectra of two known B[e] supergiants in the Large Magellanic Cloud, using the Very Large Telescope's Spectrograph for INtegral Field Observation in the Near-Infrared (VLT/SINFONI). Both stars clearly show the $^{13}$CO band emission, whose strength implies ...

  2. 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.

  3. Carbon-13 spin lattice relaxation and photoelectron spectroscopy of some aromatic sulphides and sulphones

    International Nuclear Information System (INIS)

    Carbon-13 NMR spectroscopy and photoelectron spectroscopy have been used to study the electronic structure of symmetric dithienothiophenes and corresponding sulphones. The physical data obtained from both spectroscopic techniques have been interpreted with the aid of quantum mechanical calculations. (Auth.)

  4. 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

  5. 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

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

    International Nuclear Information System (INIS)

    Highlights: • The reasonability of Chinese government’s CO2 emissions reduction allocation plan is examined. • The stochastic convergence and β-convergence are tested using the provincial panel data. • Both fixed effects and Generalized Method of Moments (GMM) estimators are utilized. • The provinces with high carbon intensity tend to experience faster reduction in carbon intensity, and vise versa. - Abstract: 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 intensity of GDP because the convergence is one of the most important intrinsic economic characteristics that policy makers should take into account: if the convergence exists, the provinces with a higher CO2 intensity of GDP tend to experience a more rapid reduction in the intensity and therefore could share a heavier burden of the intensity reduction. The existence of stochastic convergence and β-convergence is verified by employing different estimation methods and using various estimation specifications. As a result, the direct policy implication is that provinces with high CO2 intensity should be assigned tougher reduction targets to cut CO2 intensity at higher speeds, while the provinces with low carbon intensity should be allowed to reduce the CO2 intensity at a relatively lower speed. Because some social and economic indicators such as GDP per capita, industrial structure and population density may influence CO2 intensity, the policy makers should take all these factors into consideration to design reasonable reduction target allocation plan

  7. 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)

  8. Computational design of organometallic oligomers featuring 1,3-metal-carbon bonding and planar tetracoordinate carbon atoms.

    Science.gov (United States)

    Zhao, Xue-Feng; Yuan, Cai-Xia; Wang, Xiang; Li, Jia-Jia; Wu, Yan-Bo; Wang, Xiaotai

    2016-01-15

    Density functional theory computations (B3LYP) have been used to explore the chemistry of titanium-aromatic carbon "edge complexes" with 1,3-metal-carbon (1,3-MC) bonding between Ti and planar tetracoordinate Cβ . The titanium-coordinated, end-capping chlorides are replaced with OH or SH groups to afford two series of difunctional monomers that can undergo condensation to form oxide- and sulfide-bridged oligomers. The sulfide-linked oligomers have less molecular strain and are more exergonic than the corresponding oxide-linked oligomers. The HOMO-LUMO gap of the oligomers varies with their composition and decreases with growing oligomer chain. This theoretical study is intended to enrich 1,3-MC bonding and planar tetracoordinate carbon chemistry and provide interesting ideas to experimentalists. Organometallic complexes with the TiE2 (E = OH and SH) decoration on the edge of aromatic hydrocarbons have been computationally designed, which feature 1,3-metal-carbon (1,3-MC) bonding between titanium and planar tetracoordinate β-carbon. Condensation of these difunctional monomers by eliminating small molecules (H2O and H2S) produce chain-like oligomers. The HOMO-LUMO gaps of the oligomers decreases with growing oligomer chain, a trend that suggests possible semiconductor properties for oligomers with longer chains. PMID:26399226

  9. A large metabolic carbon contribution to the δ 13C record in marine aragonitic bivalve shells

    Science.gov (United States)

    Gillikin, David P.; Lorrain, Anne; Meng, Li; Dehairs, Frank

    2007-06-01

    It is well known that the incorporation of isotopically light metabolic carbon (C M) significantly affects the stable carbon isotope (δ 13C) signal recorded in biogenic carbonates. This can obscure the record of δ 13C of seawater dissolved inorganic carbon13C DIC) potentially archived in the shell carbonate. To assess the C M contribution to Mercenaria mercenaria shells collected in North Carolina, USA, we sampled seawater δ 13C DIC, tissue, hemolymph and shell δ 13C. All shells showed an ontogenic decrease in shell δ 13C, with as much as a 4‰ decrease over the lifespan of the clam. There was no apparent ontogenic change in food source indicated by soft tissue δ 13C values, therefore a change in the respired δ 13C value cannot be the cause of this decrease. Hemolymph δ 13C, on the other hand, did exhibit a negative relationship with shell height indicating that respired CO 2 does influence the δ 13C value of internal fluids and that the amount of respired CO 2 is related to the size or age of the bivalve. The percent metabolic C incorporated into the shell (%C M) was significantly higher (up to 37%, with a range from 5% to 37%) than has been found in other bivalve shells, which usually contain less than 10%C M. Interestingly, the hemolymph did contain less than 10%C M, suggesting that complex fractionation might occur between hemolymph and calcifying fluids. Simple shell biometrics explained nearly 60% of the observed variability in %C M, however, this is not robust enough to predict %C M for fossil shells. Thus, the metabolic effect on shell δ 13C cannot easily be accounted for to allow reliable δ 13C DIC reconstructions. However, there does seem to be a common effect of size, as all sites had indistinguishable slopes between the %C M and shell height (+0.19% per mm of shell height).

  10. Quantitative analysis of carbon--carbon coupling in the 13C nuclear magnetic resonance spectra of molecules biosynthesized from 13C enriched precursors

    International Nuclear Information System (INIS)

    The quantitative dependence of the intensities of the various multiplet lines arising from 13C-13C nuclear spin coupling as a function of 13C enrichment is considered. Two cases are distinguished, depending on whether or not the enrichment of the interacting carbons is statistically independent. For statistically independent labeling, the splitting is simply related to the enrichment of the various carbons. For cases in which this condition does not hold, the splitting provides a measure of the correlation in the enrichment of interacting carbons. The quantitative analysis of 13C-13C coupling is shown to provide additional information in biosynthetic experiments in which a correlation in the labeling of the substrates is introduced. In contrast to the information which is obtained by looking for the incorporation of a label into a specific position of a biosynthesized molecule, a quantitative analysis of the correlation in the labeling of the product can give information about the direct incorporation of more complex structural units. Three examples are discussed: the glycolysis of glucose to lactate, the biosynthesis of galactosylglycerol by species of red algae, and the use of doubly labeled acetate to study the biosynthetic incorporation of acetate units into more complex molecules. (U.S.)

  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. 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

  13. 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

  14. Toxins Targeting the KV1.3 Channel: Potential Immunomodulators for Autoimmune Diseases

    Directory of Open Access Journals (Sweden)

    Yipeng Zhao

    2015-05-01

    Full Text Available Autoimmune diseases are usually accompanied by tissue injury caused by autoantigen-specific T-cells. KV1.3 channels participate in modulating calcium signaling to induce T-cell proliferation, immune activation and cytokine production. Effector memory T (TEM-cells, which play major roles in many autoimmune diseases, are controlled by blocking KV1.3 channels on the membrane. Toxins derived from animal venoms have been found to selectively target a variety of ion channels, including KV1.3. By blocking the KV1.3 channel, these toxins are able to suppress the activation and proliferation of TEM cells and may improve TEM cell-mediated autoimmune diseases, such as multiple sclerosis and type I diabetes mellitus.

  15. Determination of total organic carbon content and delta(13)C in carbonate-rich detrital sediments

    OpenAIRE

    Galy, V; Julien Bouchez; C. France-Lanord;  ,

    2007-01-01

    The determination of total organic carbon content and composition in detrital sediments requires careful removal of their carbonate minerals. In detrital sediments containing large amounts of carbonates, including dolomite, this can only be achieved by liquid acid leaching that may solubilise a significant proportion of the organic carbon. For a set of detrital sediments from the Himalayan system and the Amazon River as well as five geological reference materials, we determined the proportion...

  16. 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

    Digital Repository Service at National Institute of Oceanography (India)

    Samanta, S.; Dalai, T.K.; Pattanaik, J.K.; Rai, S.K.; Mazumdar, A.

    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...

  17. CD13 is a therapeutic target in human liver cancer stem cells

    OpenAIRE

    HARAGUCHI, NAOTSUGU; Ishii, Hideshi; Mimori, Koshi; Tanaka, Fumiaki; OHKUMA, MASAHISA; Kim, Ho Min; Akita, Hirofumi; Takiuchi, Daisuke; Hatano, Hisanori; Nagano, Hiroaki; Barnard, Graham F.; Doki, Yuichiro; Mori, Masaki

    2010-01-01

    Cancer stem cells (CSCs) are generally dormant or slowly cycling tumor cells that have the ability to reconstitute tumors. They are thought to be involved in tumor resistance to chemo/radiation therapy and tumor relapse and progression. However, neither their existence nor their identity within many cancers has been well defined. Here, we have demonstrated that CD13 is a marker for semiquiescent CSCs in human liver cancer cell lines and clinical samples and that targeting these cells might pr...

  18. Intraoperative End-Tidal Carbon Dioxide Concentrations: What Is the Target?

    OpenAIRE

    Hill, Gary E.; Megan Way

    2011-01-01

    Recent publications suggest that target end-tidal carbon dioxide concentrations should be higher than values currently considered as acceptable. This paper presents evidence that end-tidal carbon dioxide values higher than concentrations that are currently targeted result in improved patient outcomes and are associated with a reduced incidence of postoperative complications.

  19. 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)

  20. 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)

  1. Carbon-13 nuclear magnetic resonance spectroscopy of [1-13C] enriched monosaccharides. Signal assignments and orientational dependence of geminal and vicinal carbon--carbon and carbon--hydrogen spin--spin coupling constants

    International Nuclear Information System (INIS)

    Early assignments of the 13C resonances in the natural abundance 13C NMR spectra of monosaccharides have been reevaluated in light of recent coupling data from the spectra of 13C-1 labeled sugars. The technique of specific 13C enrichment not only identifies the labeled carbon unambiguously but can be used to assign more remote carbon resonances due to scalar carbon-carbon coupling. The pattern of carbon-carbon coupling observed in all of the sugars thus far studied is remarkably constant. In addition to the large (approximately 46 Hz) one-bond coupling between C-1 and C-2, C-3 exhibits a coupling to C-1 only in the β anomer (approximately 4 Hz) while C-5 is coupled to C-1 only in the α anomer (approximately 2 Hz). In addition, C-6 is coupled to C-1 in both anomers and C-4 shows no evidence of coupling to C-1 in any of the sugars examined. These couplings have been used to reassign several resonances and the original assignments are discussed in terms of the predictive rules used for resonance assignments in carbohydrates. The vicinal couplings of C-6 and C-4 to C-1 appear to obey a Karplus-type relationship. The geminal 2J/sub CCC/ and 2J/sub COC/ couplings are discussed in terms of a dihedral angle dependence where the angle is defined by the relative orientations of C-3 or C-5 and the electronegative oxygen substituents on C-1. Additional data on 2J/sub CCH/ couplings involving C-1 and H-2 are also readily obtained with the C-1 labeled sugars

  2. 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

  3. Analysis of the carbon-13 and proton NMR spectra of bovine chromaffin granules.

    Science.gov (United States)

    Sharp, R R; Richards, E P

    1977-03-29

    Natural abundance carbon-13 and proton NMR spectra of bovine chromaffin granules have been obtained and analyzed using computer simulation techniques. High resolution spectra show the presence of a fluid aqueous phase containing epinephrine, ATP and a random coil protein. The protein spectrum contains unusually intense resonances due to glutamic acid and proline and has been simulated satisfactorily using the known amino acid composition of chromogranin A. The lipid phase of chromaffin granules gives rise to intense, but very broad, resonances in the carbon-13 spectrum. Protons in the lipid phase are also observable as a very rapid component of the proton-free induction decay (T2 approximately equal to 15 microns). Linewidths of the carbon-13 spectra have been used to set upper limits on rotational correlation times and on the motional anisotropy in the aqueous phase. These limits show that the aqueous phase is a simple solution (not a gel) that is isotropic over regions much larger than solute dimensions. No gel transition is observed between -3 and 25 degrees C. The carbon-13 spectra are definitely inconsistent with a lipoprotein matrix model and chromaffin granules previously proposed by Helle and Serck-Hanssen ((1975) Mol. Cell, Biochem. 6, 127-146). Relative carbon-13 intensities of ATP and epinephrine are not consistent with the known 1 : 4 mol ratio of these components. This fact suggests that epinephrine and ATP are not directly complexed in intact chromaffin granules. PMID:849474

  4. Depletion of 13C in lignin and its implications for stable carbon isotope studies

    International Nuclear Information System (INIS)

    Stable carbon isotope compositions of organic matter are now widely used to trace carbon flow in ecosystems, and have been instrumental in shaping current perceptions of the importance of terrestrial vegetation to estuarine and coastal marine environments. A general assumption in these and other studies relying on carbon isotope compositions for source identification of organic matter has been that the major biochemical components of plant tissues are isotopically invariant. We report here large differences between the carbon isotope compositions of the polysaccharide and lignin components of a variety of vascular plants, including the salt-marsh grass Spartina alterniflora, and demonstrate that the carbon isotope composition of Spartina detritus gradually changes during biogeochemical processing as polysaccharides are preferentially removed, leaving a material that is relatively enriched in lignin-derived carbon and depleted in 13C. (author)

  5. Determination of site-specific carbon isotope ratios at natural abundance by carbon-13 nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Caer, V; Trierweiler, M; Martin, G J; Martin, M L

    1991-10-15

    Site-specific natural isotope fractionation of hydrogen studied by deuterium NMR (SNIF-NMR) spectroscopy is a powerful source of information on hydrogen pathways occurring in biosyntheses in natural conditions. The potential of the carbon counterpart of this method has been investigated and compared. Three typical molecular species, ethanol, acetic acid, and vanillin, have been considered. Taking into account the requirements of quantitative 13C NMR, appropriate experimental procedures have been defined and the repeatability and reproducibility of the isotope ratio determinations have been checked in different conditions. It is shown that the carbon version of the SNIF-NMR method is capable of detecting small differences in the carbon-13 content of the ethyl fragment of ethanols from different botanical or synthetic origins. These results are in agreement with mass spectrometry determinations of the overall carbon isotope ratios. Deviations with respect to a statistical distribution of 13C have been detected in the case of acetic acid and vanillin. However, since the method is very sensitive to several kinds of systematic error, only a relative significance can be attached at present to the internal parameters directly accessible. Isotope dilution experiments have also been carried out in order to check the consistency of the results. In the present state of experimental accuracy, the 13C NMR method is of more limited potential than 2H SNIF-NMR spectroscopy. However it may provide complementary information. Moreover it is particularly efficient for detecting and quantifying adulterations that aim to mimic the overall carbon-13 content of a natural compound by adding a selectivity enriched species to a less expensive substrate from a different origin. PMID:1759714

  6. 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).

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

    DEFF Research Database (Denmark)

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

    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....

  8. The range of 1-3 keV electrons in solid oxygen and carbon monoxide

    International Nuclear Information System (INIS)

    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 on 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. (orig.)

  9. 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....

  10. Tests of carbon targets for 12C+12C reactions at astrophysical energies

    International Nuclear Information System (INIS)

    As a preliminary step towards measurements of the 12C +12 C reactions at astrophysical energies, we investigate the behaviour of targets under beam bombardment, specifically the quantitative relation between hydrogen and deuterium content of different carbon targets and target temperature. Experiments have taken place at the CIRCE accelerator in Caserta, Italy and preliminary results are presented here

  11. 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.

  12. Calculation of Lifetime of Charge-Exchanging Carbon Targets in Intense Heavy Ion Beams

    CERN Document Server

    Gikal, B N; Kazacha, V I; Kamanin, D V

    2005-01-01

    Influence of the radiation damage and sublimation effects on the lifetime of carbon targets used for the accelerated ion beam extraction from cyclotrons by the charge-exchanging method is considered. The theoretical models permitting evaluation of the carbon target lifetime depending on their and ion beam parameters are presented both for the radiation damage and sublimation effects. It is shown that for the U-400 cyclotron carbon targets 50 $\\mu$g/cm$^{2}$ thick and for the ion beam flux density up to 100 p$\\mu$A/cm$^{2}$ the main effect defining the carbon target lifetime is the radiation damage. If the carbon target thickness and the ion beam flux density are greater, the target lifetime is defined already by the sublimation effect. In this connection "casting pipes" can be formed in the target, affecting on the mean energy and the energy distribution dispersion of the ion beam flied through the target. Comparison of measured and calculated target lifetimes is carried out

  13. 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.

  14. Demonstration of a highly coherent 13.9 nm x-ray laser from a silver tape target

    International Nuclear Information System (INIS)

    A highly coherent 13.9 nm x-ray laser (XRL) is generated under an oscillator-amplifier configuration using a new tape target system and a driver laser system with a 0.1 Hz repetition rate. The output energy is comparable to the XRL generated with a silver-deposited slab target, and the pointing stability using the new tape target system is better than conventional slab targets.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. Application of carbon-13 and phosphorous-31 NMR to follow phosphinites and rhodium catalysts synthesis

    International Nuclear Information System (INIS)

    Phosphinites and thiophosphites derived from bicyclic and polycyclic strained molecules like norbonanes, endo-endo and endo-exo tetracyclic dodecanes compounds, and their respective cationic Rhodium catalysts, were prepared. Carbon-13 and Phosphorus-31 NMR were used to identify the synthesized compounds. (author)

  20. Carbon Nanotubes: An Emerging Drug Carrier for Targeting Cancer Cells

    OpenAIRE

    Vaibhav Rastogi; Pragya Yadav; Shiv Sankar Bhattacharya; Arun Kumar Mishra; Navneet Verma; Anurag Verma; Jayanta Kumar Pandit

    2014-01-01

    During recent years carbon nanotubes (CNTs) have been attracted by many researchers as a drug delivery carrier. CNTs are the third allotropic form of carbon-fullerenes which were rolled into cylindrical tubes. To be integrated into the biological systems, CNTs can be chemically modified or functionalised with therapeutically active molecules by forming stable covalent bonds or supramolecular assemblies based on noncovalent interactions. Owing to their high carrying capacity, biocompatibility,...

  1. 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.

  2. 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)

  3. 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.

  4. 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.

  5. 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

  6. Changes of stable isotopes carbon-13 and nitrogen-15 in different tissues of cattle

    International Nuclear Information System (INIS)

    Stable isotope analysis is a potential tool for tracing food origin. The stable carbon and nitrogen isotope composition in different tissues of two varieties of cattle under the same culture condition were investigated. δ 13C and δ15N values of different defatted muscle and crude fat, cattle tail hair, blood, liver and feed were determined by isotope ratio mass spectrometry, and statistical analysis was carried out. The results showed that stable isotopes of carbon and nitrogen composition was not affected by cattle variety; the δ 13C values between different defatted muscle, blood, liver and cattle hair were not significantly different, but δ 15N value in the liver was much higher than other muscle and the δ 13C values didn't show difference among all the crude fat samples. So these results indicated that isotope fractionation in the various tissue was discrepant. (authors)

  7. 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.

  8. 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

  9. 13C NMR spectroscopy of amorphous hydrogenated carbon and amorphous hydrogenated boron carbide

    International Nuclear Information System (INIS)

    We report the 13C NMR spectrum of amorphous hydrogenated carbon and boron carbide. The amorphous hydrogenated carbon spectra consist primarily of an sp3 line at 40 ppm and an sp2 line at 140 ppm and are in reasonable agreement with the recent theoretical calculations of Mauri, Pfrommer, and Louie, but there are some notable discrepancies. The amorphous hydrogenated boron carbide spectra are very different from those of amorphous hydrogenated carbon, being dominated by one line at 15 ppm. We interpret this line as due to carbon bound in boron carbide icosahedra, because polycrystalline boron carbide with boron carbide icosahedra as the unit cell gives very similar NMR spectra. copyright 1999 The American Physical Society

  10. 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 ...

  11. Comparison of infrared and mass-spectrometric measurements of carbon-13/carbon-12 ratios

    International Nuclear Information System (INIS)

    The delta13C values of 20 breath samples and 10 tank-CO2 samples (delta13C values ranged from -31.3 to +148.9per mille vs PDB) and the CO2 concentrations of three breath samples and 10 tank-CO2 samples were measured with a commercial prototype of a diode-laser i.r. spectrophotometer, MAT I. The results were compared with those obtained by gas-isotope-ratio mass spectrometry and by gas chromatography. Precisions (ssub(x), n=10) of 0.2per mille and 0.6% were calculated for 13C/12C ratios and CO2 concentrations, respectively, using the MAT I system. (author)

  12. Stable Carbon Isotope Ratios for Giant Stars in the Globular Cluster M13

    Science.gov (United States)

    Rhee, Jaehyon; Pilachowski, C. A.

    2013-01-01

    Recently, our paradigm for the formation and evolution of globular clusters has shifted. We now understand that the majority of present-day stars in globular clusters formed as second-generation stars, primarily from the ejecta of first-generation AGB stars, while the majority of first generation, less centrally concentrated stars, have been dynamically lost to the cluster (D'Ercole et al. 2011). This paradigm explains the observed star-to-star variations in the abundances of light element observed in globular clusters, and suggests that the carbon isotope ratio should be similarly differentiated between first and second generation stars. In an effort to verify this scenario, we have recently utilized the Gemini/NIFS to determine carbon isotope abundances (12C and 13C) for 18 giant stars in the globular clusters M13 through medium-resolution (R ˜ 5300) infrared spectroscopy of the first-overtone CO bands near 2.3 μm. Our program stars are distributed from the tip of the RGB to the BLF (the bump in the luminosity function) of M13, and their Na, Mg, and Al abundances are already known from homogeneous data set analysis. Therefore, adding reliable abundances of the stable carbon isotopes to this homogeneous spectroscopic sample permits systematic tests of cluster chemical evolution models. We report preliminary results of the carbon abundance analysis for our NIFS K-band spectra and present an overview of our ongoing effort with other globular clusters.

  13. Design of an intense muon source with a carbon and mercury target

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, D.; Berg, J. S.; Neuffer, D.; Ding, X.

    2015-05-03

    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.

  14. 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

  15. 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.

  16. Routes And Rates Of Carbon Input In A Temperate Forest Demonstrated By A Large Scale 13C Tracer Experiment

    International Nuclear Information System (INIS)

    The fate of recently assimilated carbon in mature deciduous trees, which are exposed to elevated and 13C depleted CO2, was traced within the Swiss Canopy Crane (SCC) project. Our findings suggest that substantial amounts of carbon are allocated into short living pools. Therefore, increased carbon storage under rising atmospheric CO2 is unlikely. (author)

  17. Provincial allocation of carbon emission reduction targets in China: An approach based on improved fuzzy cluster and Shapley value decomposition

    International Nuclear Information System (INIS)

    An approach to determine carbon emission reduction target allocation based on the particle swarm optimization (PSO) algorithm, fuzzy c-means (FCM) clustering algorithm, and Shapley decomposition (PSO–FCM–Shapley) is proposed in this study. The method decomposes total carbon emissions into an interaction result of four components (i.e., emissions from primary, secondary, and tertiary industries, and from residential areas) which composed totally by 13 macro influential factors according to the KAYA identity. Then, 30 provinces in China are clustered into four classes according to the influential factors via the PSO–FCM clustering method. The key factors that determine emission growth in the provinces representing each cluster are investigated by applying Shapley value decomposition. Finally, based on guaranteed survival emissions, the reduction burden is allocated by controlling the key factors that decelerate CO2 emission growth rate according to the present economic development level, energy endowments, living standards, and the emission intensity of each province. A case study of the allocation of CO2 intensity reduction targets in China by 2020 is then conducted via the proposed method. The per capita added value of the secondary industry is the primary factor for the increasing carbon emissions in provinces. Therefore, China should limit the growth rate of its secondary industry to mitigate emission growth. Provinces with high cardinality of emissions have to shoulder the largest reduction, whereas provinces with low emission intensity met the minimum requirements for emission in 2010. Fifteen provinces are expected to exceed the national average decrease rates from 2011 to 2020. - Highlights: • A PSO–FCM–Shapley approach for carbon emission reduction target allocation is proposed. • Provinces of China are clustered into four classes based on factors influencing carbon emissions. • Provinces with large total emissions and high emission intensity

  18. 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.

  19. 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.

  20. 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.

  1. Carbon-13 nuclear magnetic resonance studies of trans-diacido(tetraamine)cobalt(III)

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, G.R.; Johnson, D.W.

    1982-06-01

    Carbon-13 nuclear magnetic resonance spectra of a series of trans-diacido(1,10-diamino-4,7-diazadecane)cobalt(III) complexes (trans-Co(3,2,3-tet)X/sub 2/, X = Br/sup -/, Cl/sup -/, N/sub 3//sup -/, NO/sub 2//sup -/, OAc) and trans-diacido(1,9-diamino-3,7-diazononane)cobalt(III) complexes (trans-Co(2,3,2-tet)X/sub 2/, X = Cl/sup -/, GlyH, /sup -/OAc, NH/sub 3/, NO/sub 2//sup -/) will be discussed. The /sup 13/C chemical shift is found to be linearly dependent on the ligand field strength (estimated from the electronic spectrum) of the axial ligands (X). The shielding of selected carbon atoms within the tetraamine ligand, which has been attributed to the central metal ion, increases with increasing axial ligand field strength.

  2. 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...

  3. 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

  4. Hydrothermal carbon from biomass: structural differences between hydrothermal and pyrolyzed carbons via 13C solid state NMR.

    Science.gov (United States)

    Falco, Camillo; Perez Caballero, Fernando; Babonneau, Florence; Gervais, Christel; Laurent, Guillaume; Titirici, Maria-Magdalena; Baccile, Niki

    2011-12-01

    The objective of this paper is to better describe the structure of the hydrothermal carbon (HTC) process and put it in relationship with the more classical pyrolytic carbons. Indeed, despite the low energetic impact and the number of applications described so far for HTC, very little is known about the structure, reaction mechanism, and the way these materials relate to coals. Are HTC and calcination processes equivalent? Are the structures of the processed materials related to each other in any way? Which is the extent of polyaromatic hydrocarbons (PAH) inside HTC? In this work, the effect of hydrothermal treatment and pyrolysis are compared on glucose, a good model carbohydrate; a detailed single-quantum double-quantum (SQ-DQ) solid state (13)C NMR study of the HTC and calcined HTC is used to interpret the spectral region corresponding to the signal of furanic and arene groups. These data are compared to the spectroscopic signatures of calcined glucose, starch, and xylose. A semiquantitative analysis of the (13)C NMR spectra provides an estimation of the furanic-to-arene ratio which varies from 1:1 to 4:1 according to the processing conditions and carbohydrate employed. In addition, we formulate some hypothesis, validated by DFT (density functional theory) modeling associated with (13)C NMR chemical shifts calculations, about the possible furan-rich structural intermediates that occur in the coalification process leading to condensed polyaromatic structures. In combination with a broad parallel study on the HTC processing conditions effect on glucose, cellulose, and raw biomass (Falco, C.; Baccile, N.; Titirici, M.-M. Green Chem., 2011, DOI: 10.1039/C1GC15742F), we propose a broad reaction scheme and in which we show that, through HTC, it is possible to tune the furan-to-arene ratio composing the aromatic core of the produced HTC carbons, which is not possible if calcination is used alone, in the temperature range below 350 °C. PMID:22050004

  5. Short-term carbon and nitrogen cycling in urine patches assessed by combined carbon-13 and nitrogen-15 labelling

    DEFF Research Database (Denmark)

    Ambus, Per; Petersen, S.O.; Soussana, J.F.

    2007-01-01

    ) fuel denitrification activity and N2O production. The study took advantage of carbon-13 pulse labelling the plant tissue combined with application of nitrogen-15 labelled synthetic urine as an attempt to identify the sources of N2O. Over a 6 weeks course, the CO2 evolved in response to urine...... indicating that root death was not a significant source to available C. Nitrous oxide emissions accumulated to 7, 59, 142 and 77 mg N2O-N m(-2), respectively, for control (0N), low urine N (LUN), high urine N (HUN) and high mineral N (HMN) treatments. Pair-wise comparisons indicated that HUN > LUN (P < 0...

  6. 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

  7. 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

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

    Science.gov (United States)

    Lehmeier, C. A.; Ballantyne, F., IV; Min, K.; Billings, S. A.

    2015-10-01

    Understanding how carbon dioxide (CO2) flux from soils feeds back to climate warming depends in part on our ability to quantify the efficiency with which microorganisms convert soil 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 soil organic substrates. However, the diversity of organic substrates' δ13C and the challenges of measuring microbial C use efficiency (CUE) in soils fundamentally limit our ability to project soil, and thus 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 soil microorganism growing at a constant rate. Specific respiration rate increased by 250 % between 13 and 26.5 °C, decreasing CUE from 77 to 56 %. 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 soil C fluxes.

  9. 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.

  10. 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。

  11. Multiple targets of carbon monoxide gas in the intestinal inflammation.

    Science.gov (United States)

    Naito, Yuji; Takagi, Tomohisa; Uchiyama, Kazuhiko; Katada, Kazuhiro; Yoshikawa, Toshikazu

    2016-04-01

    Inflammatory bowel diseases (IBDs) such as ulcerative colitis and Crohn's disease are chronic relapsing and remitting inflammatory disorders of the intestinal tract. It is important to investigate the precise pathogenesis of IBD, to evaluate new anti-inflammatory agents, and to develop novel drugs. Carbon monoxide (CO) has emerged as an important regulator of acute and chronic inflammation of the gastrointestinal tract. The mechanism underlying its anti-inflammatory effects is only partially understood. Recent reports have demonstrated that CO could play a role in the functional modulation of epithelial and immunological cells in the intestine. In this short review, we have highlighted the recent findings that CO stimulates the epithelial cell restitution and FGF production from myofibroblasts. CO was also shown to regulate T cell activation and differentiation, and to activate macrophages. Finally, we have discussed the direction of translational research with respect to launching a novel agent for releasing CO in the intestine. PMID:27095232

  12. 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

  13. Estimation of glucose carbon recycling in children with glycogen storage disease: A 13C NMR study using [U-13C]glucose

    International Nuclear Information System (INIS)

    A stable isotope procedure to estimate hepatic glucose carbon recycling and thereby elucidate the mechanism by which glucose is produced in patients lacking glucose 6-phosphatase is described. A total of 10 studies was performed in children with glycogen storage disease type I (GSD-I) and type III (GSD-III) and control subjects. A primed dose-constant nasogastric infusion of D-[U-13C]glucose or an infusion diluted with nonlabeled glucose solution was administered following different periods of fasting. Hepatic glucose carbon recycling was estimated from 13C NMR spectra. The values obtained for GSD-I patients coincided with the standard [U-13C]glucose dilution curve. These results indicate that the plasma glucose of GSD-I subjects comprises only a mixture of 99% 13C-enriched D-[U-13C]glucose and unlabeled glucose but lacks any recycled glucose. Significantly different glucose carbon recycling values were obtained for two GSD-III patients in comparison to GSD-I patients. The results eliminate a mechanism for glucose production in GSD-I children involving gluconeogenesis. However, glucose release by amylo-1,6-glucosidase activity would result in endogenous glucose production of non-13C-labeled and nonrecycled glucose carbon, as was found in this study. In GSD-III patients gluconeogenesis is suggested as the major route for endogenous glucose synthesis. The contribution of the triose-phosphate pathway in these patients has been determined

  14. 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.

  15. 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

  16. Study of the potential of low carbon energy development and its contribution to realize the reduction target of carbon intensity in China

    International Nuclear Information System (INIS)

    Appraising low carbon energy potential in China and studying its contribution to China's target of cutting CO2 emissions by 40–45% per unit of GDP by 2020 is crucial for taking countermeasures against climate change and identifying low carbon energy development strategies. This paper presents two scenarios and evaluates the development potential for low carbon energy and its various sources. Based on the evaluation, we analyze how low carbon energy contributes to achieving China's national target of carbon intensity reduction. We draw several conclusions from the analysis. First, low carbon energy will contribute 9.74% (minimum) to 24.42% (maximum) toward the 2020 carbon intensity target under three economic development schemes. Second, the contribution will decrease when the GDP growth rate increases. Third, to maintain the same contribution with high GDP growth rates, China should not only strengthen its investment and policy stimulation for low carbon energy but also simultaneously optimize economic structures and improve carbon productivity. - Highlights: ► Low carbon energy can substitute at least 659.5 Mtce of fossil energy in 2020. ► Potential of hydropower ranks first among all low carbon energy sources in 2020. ► Low carbon energy will contribute at least 9.47% to reach carbon target in 2020. ► China should formulate and implement comprehensive measures to cut carbon emission.

  17. 13C-enrichment at carbons 8 and 2 of uric acid after 13C-labeled folate dose in man

    International Nuclear Information System (INIS)

    To evaluate folate-dependent carbon incorporation into the purine ring, we measured 13C-enrichment independently at C2 and C8 of urinary uric acid (the final catabolite of purines) in a healthy male after an independent oral dose of [6RS]-5-[13C]-formyltetrahydrofolate ([6RS]-5-H13CO-H4folate) or 10-H13CO-7,8-dihydrofolate (10-H13CO-H2folate). The C2 position was 13C-enriched more than C8 after [6RS]-5-H13CO-H4folate, and C2 was exclusively enriched after 10-H13CO-H2folate. The enrichment of C2 was greater from [6RS]-5-H13CO-H4folate than 10-H13CO-H2folate using equimolar bioactive doses. Our data suggest that formyl C of [6RS]-10-H13CO-H4folate was not equally utilized by glycinamide ribotide transformylase (enriches C8) and aminoimidazolecarboxamide ribotide (AICAR) transformylase (enriches C2), and the formyl C of 10-H13CO-H2folate was exclusively used by AICAR transformylase. 10-HCO-H2folate may function in vivo as the predominant substrate for AICAR transformylase in humans

  18. Soil carbon cycle 13C responses in the decade following bark beetle and girdling disturbance

    Science.gov (United States)

    Maurer, G. E.; Chan, A. M.; Trahan, N. A.; Moore, D. J.; Bowling, D. R.

    2014-12-01

    Recent bark beetle outbreaks in western North America have impacted millions of hectares of conifer forests leading to uncertainty about whether these forests will become new sources of atmospheric CO2. In large part, this depends on whether enhanced respiration from the decomposition of newly dead organic matter will outpace the recovery of ecosystem carbon uptake by the ecosystems. To understand how rapidly conifer forest carbon pools turn over following these disturbances, we examined changes in the isotopic composition of soil respiration (δ13Cresp) following beetle and girdling mortality in two subalpine forests in Colorado, U.S.A. At the beetle-impacted forest δ13Cresp declined by ~1‰ between 3 and 8 years post-disturbance, but recovered in years 9-10. In the girdled forest, deep (<10 cm depth) soil respiration from plots at <1 to 2 years post-girdling was depleted by ~1‰ relative to ungirdled plots, but then gradually increased until there was a significant spike in δ13Cresp at 8-9 years post-girdling. Based on our understanding of isotopic composition in carbon pools and fluxes at these forests, we attribute these changes to removal of recently assimilated C in rhizosphere respiration (1-2 years) followed by the decomposition of litterfall (needles and roots) 8-10 years post-disturbance. Relative to ungirdled plots, there was also a transient enrichment in surface δ13Cresp from plots at <1 to 2 years post-girdling (~0.5‰, not statistically significant) and significant declines in microbial carbon in surface soils in 2-4 year post-girdling plots. Again, based on current understanding, we interpret these to signify the rapid turnover of mycorrhizal and rhizosphere microbial biomass in the 2 years following girdling. A potential confounding factor in this study is that seasonal variation in δ13Cresp was similar in magnitude to changes with time since disturbance and was significantly related to variation in soil temperature and water content.

  19. Isotope separation of carbon-13 by counter-current column with exchange reaction between carbon dioxide and carbamic acid

    International Nuclear Information System (INIS)

    The isotope separation performance of carbon-13 with exchange reaction between CO2 and carbamic acid was studied and some factors for the counter-current column were studied for improving the overall performance. The working fluid for the experiments was a solution of DNBA, (C4H9)2NH, and n-octane mixture. The rate-controlling step of 13C transfer at temperatures higher than 10 deg C was the exchange reaction between carbamic acid and CO2 dissolved by physical absorption. The capacity coefficient of 13C transfer between gas and liquid in the counter-current column was successfully related to the product of three factors: the concentration of carbamic acid, the concentration of CO2 dissolved by physical absorption and the liquid holdup of the column. The liquid holdup was also an important factor. As the holdup increased, the isotope exchange rate and the overall separation factor of the column increased. However, the transient time to equilibrium was much longer. (author)

  20. Probabilistic quantification of allowable carbon emissions for meeting multiple climate targets

    Science.gov (United States)

    Steinacher, M.; Joos, F.; Stocker, T. F.

    2013-12-01

    Climate targets are designed to inform policies that would limit the magnitude and impacts of climate change caused by anthropogenic emissions of greenhouse gases and other substances. The target that is currently recognized by most world governments places a limit of two degrees Celsius on the global mean warming since preindustrial times. This would require large sustained reductions in carbon dioxide emissions during the twenty-first century and beyond. Such a global temperature target, however, is not sufficient to control many other quantities, such as transient sea level rise, ocean acidification, and net primary production on land. Here, using an Earth system model of intermediate complexity (EMIC) in an observation-informed Bayesian approach, we show that allowable carbon emissions are substantially reduced when multiple climate targets are set. We take into account uncertainties in physical and carbon cycle model parameters, radiative efficiencies, climate sensitivity, and carbon cycle feedbacks by varying nineteen key model parameters. A broad set of site-specific and gridded observational data from atmosphere, ocean, and land is used to constrain the model ensemble to realizations that are compatible with observations. Within this framework, we explore a broad range of economically feasible greenhouse gas scenarios from the integrated assessment community to determine the likelihood of meeting a combination of specific global and regional targets under various assumptions. For any given likelihood of meeting a set of such targets, the allowable cumulative emissions are greatly reduced from those inferred from the temperature target alone. Therefore, temperature targets alone are unable to comprehensively limit the risks from anthropogenic emissions.

  1. 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)

  2. 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

  3. One-carbon 13C-labeled synthetic intermediates. Comparison and evaluation of preparative methods

    International Nuclear Information System (INIS)

    Frequently the biggest stumbling block to the synthesis of a structurally complex labeled compound is obtaining the required low molecular weight, structurally simple, isotopic intermediates. Selection of a particular scheme from various alternatives depends on the available capabilities and quantity of product desired, as well as on anticipated future requirements and need for related compounds. Many of the newer reagents for organic synthesis can be applied effectively to isotopic preparations with improvements of yields and simplification of procedures compared to established classical methods. New routes developed for higher molecular weight compounds are sometimes not directly adaptable to the one-carbon analogs, either because of isolation difficulties occasioned by physical properties or by chemical reactivities peculiar to their being first members of homologous series. Various routes for preparation of carbon-13 labeled methanol, formaldehyde, and cyanide are compared

  4. 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).

  5. Carbon-13 solid state NMR studies in the aromatization of residual coals from hydropyrolised cellulose

    International Nuclear Information System (INIS)

    Pure cellulose was pyrolyzed is a fixed-bed reactor under hydrogen pressure (hydropyrolysis). Residual chars were collected and analysed by solid state nmr 13 C (CP-MAS) and elemental. Hydrophyrolysis parameters such as final temperature in the range of 300 to 520 deg C and hydrogen pressure from 5 to 100 atm gave different char samples. CP-MAS spectra were obtained in a BRUKER MSL-100 spectrometer. The results showed that the aromatic and aliphatic fractions had strong dependence with temperature and no influence with pressure. Elemental analysis indicated the carbon content increased more with temperature than the pressure increasing. (author)

  6. Gastric Hyperplasia in Mice With Targeted Disruption of the Carbonic Anhydrase Gene Car9

    Czech Academy of Sciences Publication Activity Database

    Ortova Gut, M.; Parkkila, S.; Vernerová, Z.; Rohde, E.; Závada, Jan; Höcker, M.; Pastorek, J.; Karttunen, T.; Gibadulinová, G.; Závadová, Zuzana; Knobeloch, K. P.; Wiedenmann, B.; Svoboda, Jan; Horak, I.; Pastoreková, S.

    2002-01-01

    Roč. 123, č. 12 (2002), s. 1889-1903. ISSN 0016-5085 R&D Projects: GA ČR GV312/96/K205 Keywords : Carbonic Anhydrases * Knock-aou * Differantiation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 13.440, year: 2002

  7. Gastric hyperplasia in mice with targeted disruption of the carbonic anhydrase gene Car9

    Czech Academy of Sciences Publication Activity Database

    Ortova-Gut, M.; Parkkila, S.; Vernerová, Z.; Rohde, E.; Závada, Jan; Hocker, M.; Pastorek, J.; Karttunen, T.; Gibadulinová, A.; Závadová, Zuzana; Knobeloch, K.-P.; Wiedernmann, B.; Svoboda, Jan; Horak, I.; Pastoreková, S.

    2002-01-01

    Roč. 123, č. 6 (2002), s. 1889-1903. ISSN 0016-5085 R&D Projects: GA ČR GV312/96/K205 Institutional research plan: CEZ:AV0Z5052915 Keywords : mouse carbonic anhydrase Car9 * gastric hyperplasia Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 13.440, year: 2002

  8. 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

  9. Targeted Killing of Cancer Cells In vivo and In vitro with EGF-directed Carbon Nanotube-based Drug Delivery

    OpenAIRE

    Bhirde, Ashwin A; Patel, Vyomesh; Gavard, Julie; Zhang, Guofeng; Sousa, Alioscka A.; Masedunskas, Andrius; Leapman, Richard D.; Weigert, Roberto; Gutkind, J. Silvio; Rusling, James F.

    2009-01-01

    Carbon nanotube-based drug delivery holds great promise for cancer therapy. Herein we report the first targeted, in vivo killing of cancer cells using a drug-single wall carbon nanotube (SWNT) bioconjugate, and demonstrate efficacy superior to non-targeted bioconjugates. First line anti-cancer agent cisplatin and epidermal growth factor (EGF) were attached to SWNTs to specifically target squamous cancer, and the non-targeted control was SWNT-cisplatin without EGF. Initialin vitro imaging stud...

  10. 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

  11. Preparation and physico-chemical study of nitroxide radicals. Isotopic marking with carbon 13 and deuterium

    International Nuclear Information System (INIS)

    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 13C in the α or β position of the nitroxide function has been carried out. The coupling with an α 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 aH which is always less than that of the ethyl. On the other hand, the 13C 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 β couplings. (author)

  12. Cheminformatics-based drug design approach for identification of inhibitors targeting the characteristic residues of MMP-13 hemopexin domain.

    Directory of Open Access Journals (Sweden)

    Roopa Kothapalli

    Full Text Available BACKGROUND: MMP-13, a zinc dependent protease which catalyses the cleavage of type II collagen, is expressed in osteoarthritis (OA and rheumatoid arthritis (RA patients, but not in normal adult tissues. Therefore, the protease has been intensively studied as a target for the inhibition of progression of OA and RA. Recent reports suggest that selective inhibition of MMP-13 may be achieved by targeting the hemopexin (Hpx domain of the protease, which is critical for substrate specificity. In this study, we applied a cheminformatics-based drug design approach for the identification and characterization of inhibitors targeting the amino acid residues characteristic to Hpx domain of MMP-13; these inhibitors may potentially be employed in the treatment of OA and RA. METHODOLOGY/PRINCIPAL FINDINGS: Sequence-based mutual information analysis revealed five characteristic (completely conserved and unique, putative functional residues of the Hpx domain of MMP-13 (these residues hereafter are referred to as HCR-13(pf. Binding of a ligand to as many of the HCR-13(pf is postulated to result in an increased selective inhibition of the Hpx domain of MMP-13. Through the in silico structure-based high-throughput virtual screening (HTVS method of Glide, against a large public library of 16908 molecules from Maybridge, PubChem and Binding, we identified 25 ligands that interact with at least one of the HCR-13(pf. Assessment of cross-reactivity of the 25 ligands with MMP-1 and MMP-8, members of the collagenase family as MMP-13, returned seven lead molecules that did not bind to any one of the putative functional residues of Hpx domain of MMP-1 and any of the catalytic active site residues of MMP-1 and -8, suggesting that the ligands are not likely to interact with the functional or catalytic residues of other MMPs. Further, in silico analysis of physicochemical and pharmacokinetic parameters based on Lipinski's rule of five and ADMET (absorption, distribution

  13. 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...

  14. 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.

  15. 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

  16. Design study of Be-target for proton accelerator based neutron source with 13MeV cyclotron

    International Nuclear Information System (INIS)

    There is a cyclotron named KIRAMS-13 in Pusan National University, Busan, Korea, which has the proton energy of 13MeV and the beam current of 0.05mA. Originally, it was developed for producing medical radioisotopes and nuclear physics research. To improve the utilization of the facility, we are considering the possibilities of installing a neutron generation target in it. The Beryllium target has been considered and neutrons can be generated by 9Be(p,n)9B reaction above the threshold proton energy of 2.057MeV. In this presentation, we suggest candidate materials and structures, thicknesses, metal layers and cooling systems of target, which is optimal for the KIRAMS-13. We chose the Beryllium material of 1.14mm thick, which is calculated by stopping power of Beryllium, based on PSTAR, NIST. As for the cooling system, we chose to use water as a coolant, which will also act as a moderator. As protons pass through the target, hydrogen ions continue to pile up in the material and this makes the material brittle. To solve this problem, we chose Vanadium material because it has high hydrogen diffusion coefficient and short half-life isotope after being activated by neutrons. We simulated the neutron characteristics by the Monte Carlo simulation code, Geant4, CERN and performed thermal analysis on the target. The design of target system is very important to produce neutrons for the desired purposes. There are several other existing facilities in Korea, in addition to the cyclotron facility considered in this study, where new neutron target system can be installed and neutrons can be generated. Two prominent facilities are KOMAC, Gyeongju and RFT-30, Jeongeup and we are planning to do study on the possibilities of utilizing the accelerators for neutron generation.

  17. 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..., business development, financing, marketing, accounting, or proposal preparation. (5) SBA may...

  18. Biomass Accumulation and Carbon Stocks in 13 Different Clones of Teak (Tectona Grandis Linn. F.) in Odisha, India

    OpenAIRE

    Manoj Kumar Behera; Nilima Priyadarshini Mohapatra

    2015-01-01

    The rate of biomass accumulation and carbon stocks of 13 different clones of Teak in Odisha were studied to identify the promising genotypes suitable for massive clonal plantations in Odisha. ORANP2 produced highest biomass among the 13 clones of teak i.e. 223.72m3/ha, while ORANP1 registered lowest value of 64.05m3/ha in regards to biomass accumulation. The total carbon stock values were found in the range of 32.02-111.86t/ha for 13 different clones of teak. The Mean Annual Increment (MAI) v...

  19. Carbon-13 kinetic isotope effects in the decarbonylations of lactic acid containing 13C at the natural abundance level

    International Nuclear Information System (INIS)

    The 13C kinetic isotope fractionation in the decarbonylation of lactic acid of natural isotopic composition by sulfuric acid has been studied in the temperature range of 20-80 deg C. The 13C(1) isotope separation in the decarbonylation of lactic acid by concentrated sulfuric acid depends strongly on the temperature above 40 deg C. Below this temperature the 13C isotope effect in the decarbonylation of lactic acid by concentrated sulfuric acid is normal similarly as has been found in the decarbonylation of lactic [1-14C] acid. The experimental values of k(12C)/k(13C) ratios of isotopic rate constants for 12C and 13C are close to, but slightly higher than theoretical 13C-kinetic isotope effects calculated (neglecting tunneling) under the asumption that the C(1)-OH bond is broken in the rate-controlling step of the dehydration reaction. Dilution of concentrated sulfuric acid with water up to 1.4 molar (H2O)/(H2SO4) ratio caused the increase of the 13C isotope fractionation from 1.0273 found in concentrated sulfuric acid at 80.5 deg C to 1.0536±0.0008 (at 80.6 deg C). A discussion of the abnormally high temperature dependence of 14C and 13C isotope fractionation in this reaction and the discussion of the problem of relative 14C/13C kinetic isotope effects is given. (author) 18 refs.; 2 tabs

  20. 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...

  1. 13 C enrichment by cryogenic distillation of carbon monoxide on experimental pilot plant

    International Nuclear Information System (INIS)

    The isotope 13 C is used in many scientific fields such as: biology, medicine, chemistry and environmental studies. The recent advances in analytical techniques have determined an important demand for this isotope. The most used method for 13 C separation in large quantities is the cryogenic distillation of carbon monoxide at 81 K. The single stage separation factor (α) for 13 C is 1.01 - 1.007 at 70 - 81 K. A 13 C separation plant by cryogenic distillation of CO was built in the Separation Laboratory of ITIM Cluj-Napoca.The carbon monoxide used as a feed gas for the 13 C separation plant was produced by reaction of CO2 with charcoal at 1300 K. CO was purified in a plant which has a reactor filled with Pd/Al2O3 and adsorbers with 5 mA molecular sieve. The purity of the carbon monoxide thus obtained was 99.9%. A cryogenic distillation column was used for high purification and the resulting CO, with less of 10 vol. ppm H2O and CO2, was stored in tanks. The main components of the experimental plant for the distillation of carbon monoxide at 81 K are: the condenser, a cascade with two distillation columns, boilers and thermal insulation. The condenser provides the reflux at the top of the first column by total liquefaction of CO vapours at 81 K. The used refrigerant is liquid nitrogen. The first column is 2.5 m high and 26 mm inside diameter. It is filled with Helipack type packing 2 x 2 x 0.2 mm. The reflux at the bottom of the first column is provided by an electrically heated boiler. The second column, 4.25 m high and 16 mm inside diameter, is filled with Helipack type packing 1.8 x 1.8 x 0.2 mm and has also an electrically heated boiler at the bottom. The columns have several locations for feed lines, sampling lines, pressure and temperature control. Inside the vacuum jacket, the low temperature components were wrapped in multi-layers of aluminized plastic foils, as radiation shields. A vacuum of 10-5 mm Hg was obtained. The purpose of these experiments was to

  2. 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.

  3. Experimental cascade for the separation of 13C by cryogenic distillation of carbon monoxide

    International Nuclear Information System (INIS)

    Full text: The stable isotope 13C has multiple applications as compounds labeled for studies in the fields of biology, chemistry, medicine, environment, agro-chemistry, etc. The progress in isotope analysis methodologies increased the interest in producing and using this isotope. The most used method for production of large amounts of 13C is cryogenic distillation of carbon monoxide in a cascade of several stages containing columns of different diameters with packing. Cryogenic distillation uses the differences between vapor pressures of different isotopic species, 12C16O and 13C16O, at temperatures lower than 85 K. This ratio, that is regularly named relative volatility or separation factor α equals 1.01 at 70 K and 1.007 at 81 K. The experiments were performed on experimental device in which columns as high as 7 m are used with inner diameters of 16 and 26 mm, respectively. A cascade consists of two vertical sections, the inner column 26 mm and 2.5 m height and the lower one of 16 mm inner diameter and 4.5 m length, both of them containing Helipack packing. The cooling agent used in the condenser was liquid nitrogen boiling at atmospheric pressure. The boilers were electrically heated at variable power supply. The plant is an automated system controlled by a PC. On this plant a values of HETP between 18.5 and 23 mm were obtained. After a productive experiment of the plant a product of 7.5 at. % of 13C were obtained. The obtained results fit fairly with theoretical calculations. (authors)

  4. Trends of 13C/12C ratios in pinyon tree rings of the American Southwest and the global carbon cycle

    International Nuclear Information System (INIS)

    An accurate atmospheric 13C/12C chronology can provide important constraints to models of the global carbon cycle. Trees accumulate carbon from atmospheric CO2 into growth rings and offer potential for 13C/12C reconstructions, but results have not been reproducible. This paper presents δ13C curves from 5 sites, representing 20 pinyon (Pinus edulis) trees, where cores of 4 trees from each site have been pooled into a composite sample. Isotopic analysis of cellulose in 5-yr ring groups produces curves with a general trend of decreasing δ13C after 1800, but with pronounced short-term fluctuations superimposed upon the trend. Evidence indicates the fluctuations are strongly related to moisture availability (drought). A mean curve of the 5 δ13C chronologies from which the fossil-fuel component is subtracted suggests a substantial biospheric CO2 contribution to the atmosphere since 1800

  5. 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

  6. Use of laser spectroscopy to measure the 13C/12C and 18O/16O compositions of carbonate minerals.

    Science.gov (United States)

    Barker, Shaun L L; Dipple, Gregory M; Dong, Feng; Baer, Douglas S

    2011-03-15

    The stable carbon and oxygen isotope compositions of carbonate minerals are utilized throughout the earth and environmental sciences for various purposes. Here, we demonstrate the first application of a prototype instrument, based on off-axis integrated cavity output laser spectroscopy, to measure the carbon and oxygen isotope composition of CO(2) gas evolved from the acidification of carbonate minerals. The carbon and oxygen isotope ratios were recorded from absorption spectra of (12)C(16)O(16)O, (13)C(16)O(16)O, and (12)C(16)O(18)O in the near-infrared wavelength region. The instrument was calibrated using CaCO(3) minerals with known δ(13)C(VPDB) and δ(18)O(VSMOW) values, which had been previously calibrated by isotope ratio mass spectrometry relative to the international isotopic standards NBS 18 and NBS 19. Individual analyses are demonstrated to have internal precision (1 SE) of better than 0.15‰ for δ(13)C and 0.6‰ for δ(18)O. Analysis of four carbonate standards of known isotopic composition over 2 months, determined using the original instrumental calibration, indicates that analyses are accurate to better than 0.5‰ for both δ(13)C and δ(18)O without application of standard-sample-standard corrections. PMID:21341717

  7. Equilibrium thickness of carbon target interacting with nitrogen and neon ion beams

    Science.gov (United States)

    Belkova, Yu. A.; Novikov, N. V.; Teplova, Ya. A.

    2016-04-01

    The method for calculation of the target thickness which is required for the formation of equilibrium charge distribution of ions is proposed. The description of nonequilibrium processes is based on empirical estimations of charge-exchange cross sections, taking the density effect for solids into account. The variation of the average charge and the width of the nonequilibrium charge distribution as a function of the target thickness is analyzed. The results of calculations for nitrogen and neon ions in carbon are compared with experimental data.

  8. Carbon-13 nuclear magnetic resonance of heterocyclic salts and its precursors

    International Nuclear Information System (INIS)

    The synthesis of 1,2,3,6 - tetrahydro - 1, 1 dimethyl - 3 - oxo - 5 phenylpyridinium bromides containing the substituents: H, Me, Cl, Br, OMe and NO2 is described. The phenacyl bromides (8a-f) were characterized by their melting points and by their I.r. and 1H n.m.r. spectra. Some studies on 13C n.m.r. spectra of the phenacyl bromides (8a-f), the quartenary ammonium salts (7a-f) and the cyclic salts(6a-f) are shown. The effect of substituents on the eletronic structure of these compounds and on the chemical shifts of the different carbon atoms in terms of electronic and steric effects are discussed. (M.J.C.)

  9. Carbon 13 nuclear magnetic resonance spectroscopy of cobalt(III) complexes with flexible tetraamine ligands

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, G.R.; Johnson, D.W.

    1983-10-01

    Carbon 13 NMR was found to be an extremely sensitive probe of the stereochemistry of this series of diamagnetic ''Werner'' complexes. Our interpretation is based upon two parameters, the donation of electron density to the metal and the steric perturbation required for coordination. The different symmetry of the complexes often permits determination of stereochemistry from the electronic spectrum. In addition, other methods including vibrational spectroscopy and proton NMR, have been used with some success to determine stereochemistry. These methods suffer, however, from a lack of sensitivity, especially in complexes with unsymmetrical ligands. In the course of continuing study of the stereochemistry of six coordinate transition metal complexes, we have investigated a large variety of cobalt(III) complexes with various tetraamine ligands.

  10. 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.

  11. 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.

  12. 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

  13. 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)

  14. 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 ...

  15. 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.

  16. 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

  17. 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.

  18. 13C/12C and 18O/16O in calcium carbonate-cemented beach sands ('beach rocks')

    International Nuclear Information System (INIS)

    A study of the stable isotope composition (C13/C12 and O18/O16) of the cement and the local groundwater in Itaparica Island (Salvador-Brazil) is carried out to determine the origin of the carbonate cement. For area A, the cement has Δ13C = 9% showing that CO2 in groundwater charged by decay of organic material is the source of carbonate in the cement. Probably comentation occurs during loss of excess CO2 from groundwater as comes into an environment where loss of CO2 is possible . In area B, where the cements contain, on the average Δ18O v=1,3%, the cement is formed from carbonate typical of sea water or a mixture of sea water and fresh water. (Autor)

  19. 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.

  20. Transformation behavior in low carbon 13% chromium-3% copper stainless steel; Tei C-13%Cr-3%Cu ko no hentai kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Hara, T.; Uemori, R.; Miyasaka, A. [Nippon Steel Corp., Tokyo (Japan)

    2000-10-01

    Martensitic transformation and {gamma} {yields} {alpha} transformation behavior were investigated in low carbon 13% chromium stainless steels containing 2% nickel or 3% copper. The main conclusions are as follows: (1) Hardness of 2% nickel added low carbon 13% chromium steel was independent of cooling rate after hot working at large reduction. Structure of the steel was martensitic even after being subjected to such large reduction of 75%. This result suggests that ferritic transformation was hard to occur under an usual cooling rate because austenite phase was sufficiently stablized by the addition of chromium and nickel. (2) Austenite to ferrite transformation occurred only for the low carbon 13% chromium 3% copper steel without nickel even at the small cooling rate, such as 0.01K/s. This result was mainly attributed to the unstabilization of austenite phase which caused by the precipitation of {epsilon}-Cu. Furthermore, austenite of the steel becomes easy to transform to ferrite due to heavy hot working. This phenomenon was seemed to be caused by the increase in the area of austenite grain boundary owing to recrystallization. Thus, it was considered that the nucleation of {epsilon}-Cu at the grain boundaries promoted ferrite formation. (author)

  1. Carbon-13 and deuterium isotope effects on the catalytic reactions of biotin carboxylase

    International Nuclear Information System (INIS)

    13C and 2H kinetic isotope effects have been used to investigate the mechanism of enzymic biotin carboxylation. /sup D/(V/K) is 0.50 in 80% D2O at pD 8.0 for the forward reaction and 0.57 at pD 8.5 for the phosphorylation of ADP by carbamoyl phosphate. These values approach the theoretical maximum limit for a reaction in which a proton is transferred from a sulfhydryl to a nitrogen or oxygen base. Therefore, it appears that this portion of the reaction is at or near equilibrium. 13(V/K) at pH 8 is 1.007; the small magnitude of this number suggests that the reaction is almost fully committed by the time the carbon-sensitive steps are reached. There does not appear to be a reverse commitment to the reaction under the conditions in which 13(V/K) was determined. A large forward commitment is consistent with the failure to observe positional isotope exchange from the βγ-bridge position to the β-nonbridge position in [18O4]ATP or washout of 18O from the γ-nonbridge positions. Transfer of 18O from bicarbonate to inorganic phosphate in the forward reaction was clearly observed, however. These observations suggest that biotin carboxylase exists in two distinct forms which differ in the protonation states of the two active-site bases, one of which is a sulfhydryl. Only when the sulfhydryl is ionized and the second base protonated can catalysis take place. Carboxylation of biotin is postulated to occur via a pathway in which carboxyphosphate is formed by nucleophilic attack of bicarbonate on ATP. Decarboxylation of carboxyphosphate in the active site generates CO2, which serves to carboxylate the isourea tautomer of biotin that is generated by the removal of the proton on N1' by the ionized sulfhydryl

  2. 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.

  3. 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.)

  4. 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.

  5. 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.

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

    International Nuclear Information System (INIS)

    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.)

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

    DEFF Research Database (Denmark)

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

    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...

  8. 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.

  9. 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

  10. Low-energy (30 keV) carbon ion induced mutation spectrum in the LacZα gene of M13mp18 double-stranded DNA

    International Nuclear Information System (INIS)

    Double-stranded M13mp18 DNA was irradiated with 30 keV carbon ions in dry state under vacuum to investigate the low-energy heavy ion induced mutation spectra. When the irradiated DNA was used to transfect Escherichia coli JM105, 3.6-5.7-fold increases in mutation frequency were observed, in contrast to the spontaneous group. Sequences of the 92 induced mutants showed that the carbon ions in this study could induce an interesting mutation spectrum in the lacZα gene. One-base mutations (96.8%) and base pair substitutions (56.4%) were predominant, most of which involved G:C base pairs (90.6%), especially G:C → T:A transversions (49.6%) and G:C → A:T transitions (39.6%). This is similar to the spectra induced by γ-rays in the same ds M13, wild type E. coli system. We also found a considerable amount of carbon ion induced one-base deletion (38.5%) and the mutation sites distribution on the target lacZα gene was obviously non-random. We compared this study with previous data employing γ-rays to discuss the possible causes of the mutation spectrum

  11. 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

  12. The capture and storage of carbon dioxide emissions : a significant opportunity to help Canada meet its Kyoto targets

    International Nuclear Information System (INIS)

    The current status of carbon dioxide (CO2) capture and storage technology development in Canada was reviewed and the contribution that this technology could make to lower national greenhouse gas (GHG) emissions was discussed. Other options to reducing GHG emissions include reducing energy consumption, increasing energy efficiency, adopting lower or zero carbon fuels and promoting the use of renewable energy sources. CO2 capture and storage technology involves the removal of CO2 from large sources such as power station stacks and using it where applicable, or storing it underground in geological reservoirs. The technology has potential in western Canada or in Atlantic Canada and its adjacent offshore where large fossil fuel users are located close to suitable underground reservoirs. The cost of CO2 capture is generally high because the technology is currently in the demonstration stage. The costs can be lowered when CO2 will have an economic value. It was suggested that the technology will be widely used when the costs are reduced to $20 per tonne from the current level of $35-50. The use of CO2 capture and storage technology has been included as an action plan in the First National Business Plan on Climate Change. The technology is also the main focus of a 10-year $1 billion research and development plan proposed by the Canadian Clean Power Coalition. The technology is attractive because it allows continued use of fossil fuels while simultaneously helping Canada meet its Kyoto target. 13 refs., 1 tab

  13. 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.

  14. 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

  15. 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...

  16. Conserved Amphipathic Helices Mediate Lipid Droplet Targeting of Perilipins 1-3.

    Science.gov (United States)

    Rowe, Emily R; Mimmack, Michael L; Barbosa, Antonio D; Haider, Afreen; Isaac, Iona; Ouberai, Myriam M; Thiam, Abdou Rachid; Patel, Satish; Saudek, Vladimir; Siniossoglou, Symeon; Savage, David B

    2016-03-25

    Perilipins (PLINs) play a key role in energy storage by orchestrating the activity of lipases on the surface of lipid droplets. Failure of this activity results in severe metabolic disease in humans. Unlike all other lipid droplet-associated proteins, PLINs localize almost exclusively to the phospholipid monolayer surrounding the droplet. To understand how they sense and associate with the unique topology of the droplet surface, we studied the localization of human PLINs inSaccharomyces cerevisiae,demonstrating that the targeting mechanism is highly conserved and that 11-mer repeat regions are sufficient for droplet targeting. Mutations designed to disrupt folding of this region into amphipathic helices (AHs) significantly decreased lipid droplet targetingin vivoandin vitro Finally, we demonstrated a substantial increase in the helicity of this region in the presence of detergent micelles, which was prevented by an AH-disrupting missense mutation. We conclude that highly conserved 11-mer repeat regions of PLINs target lipid droplets by folding into AHs on the droplet surface, thus enabling PLINs to regulate the interface between the hydrophobic lipid core and its surrounding hydrophilic environment. PMID:26742848

  17. 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

  18. 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)

  19. Carbon sequestration in soil beneath long-term Miscanthus plantations as determined by 13C abundance

    International Nuclear Information System (INIS)

    Miscanthus is a perennial rhizomatous warm-season grass with C4-photosynthesis. It shows considerable production potentials (10-20 t dry matter ha-1) under NW European growth conditions and plantations of Miscanthus are established to provide biomass for energy. The plant senesces in the autumn in response to adverse climatic conditions, but harvest is normally postponed until spring when the biomass is more suitable for combustion. Total pre-harvest and harvest losses may account for as much as two-thirds of autumn standing biomass and these losses provide a significant carbon input to the soil. In this study, we examine soil organic carbon (SOC) storage and turnovers beneath 9 and 16 year old Miscanthus plantations established at Hornum, Denmark (56 deg. 50'N, 09 deg. 26'E). The soil is a loamy sand (Typic Haplumbrept, coarse loamy, mixed, mesic) with a C3 vegetation history. Soil was sampled at 0-20, 20-50 and 50-100 cm depth in the Miscanthus plantations and in two reference sites under C3-plants. The 0-20 cm samples were divided into fine soil (13C/12C ratio. Rhizomes/stubbles accounted for 10.9-12.6 t DM ha-1 and coarse roots for 3.2-3.7 t DM ha-1 at 0-20 cm depth. No rhizomes and coarse roots were observed in the deeper soil layers. Concentrations of SOC were higher at all soil depths under the 16 year old Miscanthus whereas 9 years of Miscanthus and reference sites showed similar SOC concentrations. δ13C in 0-20 cm reference soil averaged -27.6 per mille while soil beneath 9 and 16 year Miscanthus showed -25.6 per mille and -22.8 per mille, respectively. Difference in δ13C between reference and Miscanthus soils was smaller at greater soil depths. SOC inventories at 0-100 cm ranged from 91-92 t C ha-1 in reference and 9 year Miscanthus to 106 t C ha-1 under 16 years of Miscanthus growing. The main part of the SOC was at 0-20 and 20-50 cm soil with 30-40 t C ha-1 in each layer. Although changes in the overall SOC storage were less significant, 13% and 31

  20. 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.

  1. 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.

  2. 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.

  3. Improved characterization of the botanical origin of sugar by carbon-13 SNIF-NMR applied to ethanol.

    Science.gov (United States)

    Thomas, Freddy; Randet, Celia; Gilbert, Alexis; Silvestre, Virginie; Jamin, Eric; Akoka, Serge; Remaud, Gerald; Segebarth, Nicolas; Guillou, Claude

    2010-11-24

    Until now, no analytical method, not even isotopic ones, had been able to differentiate between sugars coming from C4-metabolism plants (cane, maize, etc.) and some crassulacean acid metabolism plants (e.g., pineapple, agave) because in both cases the isotope distributions of the overall carbon-13/carbon-12 and site-specific deuterium/hydrogen isotope ratios are very similar. Following recent advances in the field of quantitative isotopic carbon-13 NMR measurements, a procedure for the analysis of the positional carbon-13/carbon-12 isotope ratios of ethanol derived from the sugars of pineapples and agave using the site-specific natural isotopic fractionation-nuclear magnetic resonance (SNIF-NMR) method is presented. It is shown that reproducible results can be obtained when appropriate analytical conditions are used. When applied to pineapple juice, this new method demonstrates a unique ability to detect cane and maize sugar, which are major potential adulterants, with a detection limit in the order of 15% of the total sugars, which provides an efficient mean of controlling the authenticity of juices made from this specific fruit. When applied to tequila products, this new method demonstrates a unique ability to unambiguously differentiate authentic 100% agave tequila, as well as misto tequila (made from at least 51% agave), from products made from a larger proportion of cane or maize sugar and therefore not complying with the legal definition of tequila. PMID:21028824

  4. Characterization of the recycled EVA copolymer/silica microcomposites by mechanical properties, SEM and solid state carbon-13 NMR

    International Nuclear Information System (INIS)

    The proposal of this work was to characterize the ethylene-co-vinyl acetate reject of the foot wears industry/silica (micrometer scale) composite by Tension Test, Scanning Electronic Microscopy (SEM) and Nuclear Magnetic Resonance (NMR) in solid state carbon-13. (author)

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Uncertainties in key low carbon power generation technologies - Implication for UK decarbonisation targets

    International Nuclear Information System (INIS)

    The UK government's economy-wide 60% carbon dioxide reduction target by 2050 requires a paradigm shift in the whole energy system. Numerous analytical studies have concluded that the power sector is a critical contributor to a low carbon energy system, and electricity generation has dominated the policy discussion on UK decarbonisation scenarios. However, range of technical, social and market challenges, combined with alternate market investment strategies mean that large scale deployment of key classes of low carbon electricity technologies is fraught with uncertainty. The UK MARKAL energy systems model has been used to investigate these long-term uncertainties in key electricity generation options. A range of power sector specific parametric sensitivities have been performed under a 'what-if' framework to provide a systematic exploration of least-cost energy system configurations under a broad, integrated set of input assumptions. In this paper results of six sensitivities, via restricted investments in key low carbon technologies to reflect their technical and political uncertainties, and an alternate investment strategies from perceived risk and other barriers, have been presented. (author)

  11. Non-invasive prenatal aneuploidy testing at chromosomes 13, 18, 21, X, and Y, using targeted sequencing of polymorphic loci

    Science.gov (United States)

    Zimmermann, Bernhard; Hill, Matthew; Gemelos, George; Demko, Zachary; Banjevic, Milena; Baner, Johan; Ryan, Allison; Sigurjonsson, Styrmir; Chopra, Nikhil; Dodd, Michael; Levy, Brynn; Rabinowitz, Matthew

    2012-01-01

    Objective Develop a non-invasive prenatal test based on analysis of cell-free DNA in maternal blood to detect fetal aneuploidy at chromosomes 13, 18, 21, X, and Y. Methods 166 samples from pregnant women, including eleven trisomy 21, three trisomy 18, two trisomy 13, two 45,X, and two 47,XXY samples were analyzed using an informatics-based method. Cell-free DNA from maternal blood was isolated and amplified using a multiplex PCR assay targeting 11,000 SNPs on chromosomes 13, 18, 21, X, and Y in a single reaction, then sequenced. A Bayesian-based Maximum Likelihood statistical method was applied to determine the chromosomal count of the five chromosomes interrogated in each sample, along with a sample-specific calculated accuracy for each test result. Results The algorithm correctly reported the chromosome copy number at all five chromosomes in 145 samples that passed a DNA quality test, for a total of 725/725 correct calls. The average calculated accuracy for these samples was 99.92%. Twenty-one samples did not pass the DNA quality test. Conclusions This informatics-based method non-invasively detected fetuses with trisomy 13, 18, and 21, 45,X, and 47,XXY with high sample-specific calculated accuracies for each individual chromosome and across all five chromosomes. PMID:23108718

  12. 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...

  13. Metabolic flux determination using carbon 13 NMR. Application to normal and tumoral cells from central nervous system

    International Nuclear Information System (INIS)

    Carbon 13 NMR constitutes a potent tool to study cellular metabolism by the use of 13C enriched substrates. Analyzes of 13C NMR spectra recorded from acidic cell extracts lead to the evaluation of specific enrichment of various metabolites. On the other hand, the measure of homonuclear 13C-13C spin coupling gives information on the different isotopomers for a given molecule. Mathematical models were different isotopomers for a given molecule. Mathematical models were developed to interpret the NMR data in terms of metabolic fluxes through the metabolic network of interest. Various models established in our laboratory are presented. These models were applied to metabolic studies of cultured central nervous system cells as rat cerebellar astrocytes and granule cells, and the C6 glioma cell line. (authors). 17 refs., 3 figs., 2 tabs

  14. Targeting head and neck cancer stem cells to overcome resistance to photon and carbon ion radiation.

    Science.gov (United States)

    Bertrand, Gérald; Maalouf, Mira; Boivin, Antony; Battiston-Montagne, Priscillia; Beuve, Michael; Levy, Antonin; Jalade, Patrice; Fournier, Claudia; Ardail, Dominique; Magné, Nicolas; Alphonse, Gersende; Rodriguez-Lafrasse, Claire

    2014-02-01

    Although promising new radiation therapy techniques such as hadrontherapy are currently being evaluated in the treatment of head and neck malignancies, local control of head and neck squamous cell carcinoma (HNSCC) remains low. Here, we investigated the involvement of cancer stem-like cells (CSCs) in a radioresistant HNSCC cell line (SQ20B). Stem-like cells SQ20B/SidePopulation(SP)/CD44(+)/ALDH(high) were more resistant to both photon and carbon ion irradiation compared with non-CSCs. This was confirmed by a BrdU labeling experiment, which suggests that CSCs were able to proliferate and to induce tumorigenicity after irradiation. SQ20B/SP/CD44(+)/ALDH(high) were capable of an extended G2/M arrest phase in response to photon or carbon ion irradiation compared with non-CSCs. Moreover, our data strongly suggest that resistance of CSCs may result from an imbalance between exacerbated self-renewal and proliferative capacities and the decrease in apoptotic cell death triggering. In order to modulate these processes, two targeted pharmacological strategies were tested. Firstly, UCN-01, a checkpoint kinase (Chk1) inhibitor, induced the relapse of G2/M arrest and radiosensitization of SQ20B-CSCs. Secondly, all-trans retinoic acid (ATRA) resulted in an inhibition of ALDH activity, and induction of the differentiation and radiosensitization of SQ20B/SP/CD44(+)/ALDH(high) cells. The combination of ATRA and UCN-01 treatments with irradiation drastically decreased the surviving fraction at 2Gy of SQ20B-CSCs from 0.85 to 0.38 after photon irradiation, and from 0.45 to 0.21 in response to carbon ions. Taken together, our results suggest that the combination of UCN-01 and ATRA represent a promising pharmacological-targeted strategy that significantly sensitizes CSCs to photon or carbon ion radiation. PMID:23955575

  15. 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.

  16. Mini-jets seen in cosmic ray interaction with carbon target chamber

    International Nuclear Information System (INIS)

    In this work we use two different procedures by mini jets identification in cosmic ray particles interaction with carbon target chamber (C-jets) observed by Brazil-Japan Collaboration. This events concerns the overlapping energy region with CERN and FNAL collider experiments (√ s ∼ 500 GeV). Our results are discussed and interpreted in terms of fire-ball model and we find which those studies are common in many aspects with modern version of multi-particles production models such as quark-string inspired by QCD. (author). 4 refs, 6 figs

  17. 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

  18. 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

  19. 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

  20. 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

  1. 13C chemical shift anisotropies for carbonate ions in cement minerals and the use of 13C, 27Al and 29Si MAS NMR in studies of Portland cement including limestone additions

    International Nuclear Information System (INIS)

    13C isotropic chemical shifts and chemical shift anisotropy parameters have been determined for a number of inorganic carbonates relevant in cement chemistry from slow-speed 13C MAS or 13C(1H) CP/MAS NMR spectra (9.4 T or 14.1 T) for 13C in natural abundance. The variation in the 13C chemical shift parameters is relatively small, raising some doubts that different carbonate species in Portland cement-based materials may not be sufficiently resolved in 13C MAS NMR spectra. However, it is shown that by combining 13C MAS and 13C(1H) CP/MAS NMR carbonate anions in anhydrous and hydrated phases can be distinguished, thereby providing valuable information about the reactivity of limestone in cement blends. This is illustrated for three cement pastes prepared from an ordinary Portland cement, including 0, 16, and 25 wt.% limestone, and following the hydration for up to one year. For these blends 29Si MAS NMR reveals that the limestone filler accelerates the hydration for alite and also results in a smaller fraction of tetrahedrally coordinated Al incorporated in the C-S-H phase. The latter result is more clearly observed in 27Al MAS NMR spectra of the cement–limestone blends and suggests that dissolved aluminate species in the cement–limestone blends readily react with carbonate ions from the limestone filler, forming calcium monocarboaluminate hydrate. -- Highlights: •13C chemical shift anisotropies for inorganic carbonates from 13C MAS NMR. •Narrow 13C NMR chemical shift range (163–171 ppm) for inorganic carbonates. •Anhydrous and hydrated carbonate species by 13C MAS and 13C(1H) CP/MAS NMR. •Limestone accelerates the hydration for alite in Portland – limestone cements. •Limestone reduces the amount of aluminium incorporated in the C-S-H phase

  2. 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)

  3. Carbon-13 kinetic isotope effects in the decarbonylation of lactic acid of natural isotopic composition in phosphoric acid medium

    International Nuclear Information System (INIS)

    The 13C kinetic isotope effect fractionation in the decarbonylation of lactic acid (LA) of natural isotopic composition by concentrated phosphoric acids (PA) and by 85% H3PO4 has been studied in the temperature interval of 60-150 deg C. The values of the 13C(1) isotope effects in the decarbonylation of lactic acid in 100% H3PO4, in pyrophosphoric acid and in more concentrated phosphoric acids are intermediate between the values calculated assuming that the C(1)-OH bond is broken in the rate-controlling step of dehydration and those calculated for rupture of the carbon-carbon bond in the transition state. In the temperature interval of 90-130 deg C the experimental 13C fractionation factors determined in concentrated PA approach quite closely the 13C fractionation corresponding to C(2)-C(1) bond scission. The 13C(1) kinetic isotope effects in the decarbonylation of LA in 85% orthophosphoric acid in the temperature range of 110-150 deg C coincide with the 13C isotope effects calculated assuming that the frequency corresponding to the C(1)-OH vibration is lost in the transition state of decarbonylation. A change of the mechanism of decarbonylation of LA in going from concentrated PA medium to 85% H3PO4 has been suggested. A possible secondary 18O and a primary18O kinetic isotope effect in decarbonylation of lactic acid in phosphoric acids media have been discussed, too. (author) 21 refs.; 3 tabs

  4. 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.

  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. 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.

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. Functionalized Single-Walled Carbon Nanotubes as Rationally Designed Vehicles for Tumor-Targeted Drug Delivery

    International Nuclear Information System (INIS)

    A novel single-walled carbon nanotube (SWNT)-based tumor-targeted drug delivery system (DDS) has been developed, which consists of a functionalized SWNT linked to tumor-targeting modules as well as prodrug modules. There are three key features of this nanoscale DDS: (a) use of functionalized SWNTs as a biocompatible platform for the delivery of therapeutic drugs or diagnostics, (b) conjugation of prodrug modules of an anticancer agent (taxoid with a cleavable linker) that is activated to its cytotoxic form inside the tumor cells upon internalization and in situ drug release, and (c) attachment of tumor-recognition modules (biotin and a spacer) to the nanotube surface. To prove the efficacy of this DDS, three fluorescent and fluorogenic molecular probes were designed, synthesized, characterized, and subjected to the analysis of the receptor-mediated endocytosis and drug release inside the cancer cells (L1210FR leukemia cell line) by means of confocal fluorescence microscopy. The specificity and cytotoxicity of the conjugate have also been assessed and compared with L1210 and human noncancerous cell lines. Then, it has unambiguously been proven that this tumor-targeting DDS works exactly as designed and shows high potency toward specific cancer cell lines, thereby forming a solid foundation for further development.

  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. 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)

    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 potential as a research tool in soil science and agronomy. The relatively low cost of the equipment at US$ 15000-25000 is within the research budgets of most institutes or universities. The operational simplicity of the optical system means that relatively low maintenance and minimal training are required. Thus methods were developed to prepare soil and plant materials for 13C isotope-ratio analysis using the breath test analyser, and results were compared with conventional isotope-ratio analysis by mass spectrometry. 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 data within a reasonable time frame. (author)

  17. 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.

  18. 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.

  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 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...

  20. 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

  1. 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...

  2. High-resolution solid-state carbon-13 nuclear magnetic resonance study of acetaminophen: a common analgesic drug

    OpenAIRE

    Jagannathan, NR

    1987-01-01

    Solid-state 13C-NMR spectra of acetaminophen were obtained by using proton enhancement combined with high-power decoupling and magic angle spinning. The contact time was detd. to obtain a max. signal to noise ratio. The chem. shifts obsd. were assigned to different carbons based on both conventional and nonquaternary suppression NMR spectra. In addn. there were no differences in the solid-state NMR spectra of Crocin and Tylenol tablets (com. brands of acetaminophen), except for the differe...

  3. Coupled transformation of inorganic stable carbon-13 and nitrogen-15 isotopes into higher trophic levels in a eutrophic shallow lake

    International Nuclear Information System (INIS)

    Enclosure and bag experiments were done in a eutrophic shallow lake with simultaneous use of inorganic 13C and 15N isotopes. It was demonstrated that coupled transformation of inorganic carbon and nitrogen can occur into herbivorous zooplankton through phytoplankton. Direct evidence is provided that there is an apparent coupling between photosynthesis and organic nitrogen uptake by phytoplankton during daytime under natural conditions and that the coupling occurs at a constant ratio

  4. 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...

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

    Directory of Open Access Journals (Sweden)

    F. Dehairs

    2010-05-01

    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.

  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. 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

  10. Low-density carbonized composite foams for direct-drive laser ICF targets

    International Nuclear Information System (INIS)

    The design for a direct-drive, high-gain laser inertial confinement fusion target calls for the use of a low-density, low-atomic-number foam to confine and stabilize liquid deuterium-tritium (DT) in a spherical-shell configuration. Over the past two years, we have successfully developed polystyrene foams (PS) and carbonized resorcinol-formaldehyde foams (CRF) for that purpose. Both candidates are promising materials with unique characteristics. PS has superior mechanical strength and machinability, but its relatively large thermal contraction is a significant disadvantage. CRF has outstanding wettability and dimensional stability in liquid DT; yet it is much more fragile than PS. To combine the strengths of both materials, we have recently developed a polymer composite foam which exceeds PS in mechanical strength, but retains the wettability and dimension stability of CRF. This paper will discuss the preparation, structure, and properties of the polymer composite foams. 5 refs., 1 fig., 1 tab

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

    International Nuclear Information System (INIS)

    Functionalized single-walled carbon nanotubes (SWNTs) are currently being investigated for a variety of applications, including contrast agents for medical imaging1. 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- 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. L-[METHYL-11C] Methionine Positron Emission Tomography for Target Delineation in Malignant Gliomas: Impact on Results of Carbon Ion Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: To assess the importance of 11C-methionine (MET)-positron emission tomography (PET) for clinical target volume (CTV) delineation. Methods and Materials: This retrospective study analyzed 16 patients with malignant glioma (4 patients, anaplastic astrocytoma; 12 patients, glioblastoma multiforme) treated with surgery and carbon ion radiotherapy from April 2002 to Nov 2005. The MET-PET target volume was compared with gross tumor volume and CTV, defined by using computed tomography/magnetic resonance imaging (MRI). Correlations with treatment results were evaluated between positive and negative extended volumes (EVs) of the MET-PET target for CTV. Results: Mean volumes of the MET-PET targets, CTV1 (defined by means of high-intensity volume on T2-weighted MRI), and CTV2 (defined by means of contrast-enhancement volume on T1-weighted MRI) were 6.35, 264.7, and 117.7 cm3, respectively. Mean EVs of MET-PET targets for CTV1 and CTV2 were 0.6 and 2.2 cm3, respectively. The MET-PET target volumes were included in CTV1 and CTV2 in 13 (81.3%) and 11 patients (68.8%), respectively. Patients with a negative EV for CTV1 had significantly greater survival rate (p = 0.0069), regional control (p = 0.0047), and distant control time (p = 0.0267) than those with a positive EV. Distant control time also was better in patients with a negative EV for CTV2 than those with a positive EV (p = 0.0401). Conclusions: For patients with malignant gliomas, MET-PET has a possibility to be a predictor of outcome in carbon ion radiotherapy. Direct use of MET-PET fused to planning computed tomography will be useful and yield favorable results for the therapy

  13. 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

  14. 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.

  15. 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)

  16. Analysis of dissolved organic carbon concentration and 13C isotopic signature by TOC-IRMS - assessment of analytical performance

    Science.gov (United States)

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

    2013-04-01

    Stable carbon isotopes provide a powerful tool to assess carbon pools and their dynamics. Dissolved organic carbon (DOC) has been recognized to play an important role in ecosystem functioning and carbon cycling and has therefore gained increased research interest. However, direct measurement of 13C isotopic signature of carbon in the dissolved phase is technically challenging particularly using high temperature combustion. Until recently, mainly custom-made systems existed which were modified for coupling of TOC instruments with IRMS for simultaneous assessment of C content and isotopic signature. The variety of coupled systems showed differences in their analytical performances. For analysis of DOC high temperature combustion is recognized as best performing method, owing to its high efficiency of conversion to CO2 also for highly refractory components (e.g. humic, fulvic acids) present in DOC and soil extracts. Therefore, we tested high temperature combustion TOC coupled to IRMS (developed by Elementar Group) for bulk measurements of DOC concentration and 13C signature. The instruments are coupled via an Interface to exchange the carrier gas from O2 to He and to concentrate the derived CO2 for the isotope measurement. Analytical performance of the system was assessed for a variety of organic compounds characterized by different stability and complexity, including humic acid and DOM. We tested injection volumes between 0.2-3 ml, thereby enabling measurement of broad concentration ranges. With an injection volume of 0.5 ml (n=3, preceded by 1 discarded injection), DOC and 13C signatures for concentrations between 5-150 mg C/L were analyzed with high precision (standard deviation (SD) predominantly <0.1‰), good accuracy and linearity (overall SD <0.9‰). For the same settings, slightly higher variation in precision was observed among the lower concentration range and depending upon specific system conditions. Differences in 13C signatures of about 50‰ among

  17. 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

  18. 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.

  19. 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...

  20. 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.

  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. 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.

  3. 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)

  4. 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

  5. Epidemiology of carbon monoxide gas poisoning deaths in Ardabil city, 2008-13

    Directory of Open Access Journals (Sweden)

    Esmaeil Farzaneh

    2015-04-01

    Full Text Available Background: Carbon monoxide gas is odorless, colorless and toxic which are the most abundant pollutants in the lower atmosphere. Carbon monoxide poisoning is considered as one of the most common causes of mortality in Iran and Ardabil province. This study aimed to investigate the epidemiology of carbon monoxide gas poisoning died patients during 2008 to 2013. Methods: In this descriptive cross-sectional study, with referral to the Ardabil coroner center and poisoning ward of Imam Khomeini hospital, the statistics related to carbon monoxide poisoning died patients have been extracted and entered into the Checklists then analyzed by statistical methods in SPSS.19. Results: The number of deceased in this study was 35 people with a mean age of 33.66 +/- 21.38. Of them, 19 (54.3% were male and 16 (45.7% were female. 85.7 percent of the deceased had been poisoned at home which from them 71.4% died before transaction to hospital. The season winter with 48.6% include the most of cases and the most common vehicle of intoxication was water heater with 48.6%. Conclusion: Carbon monoxide gas poisoning is one of the cases that causes to death of people in Ardabil every year and so promoting public awareness about risks due to Carbon monoxide could have a considerable role in the prevention of poisoning. [Int J Res Med Sci 2015; 3(4.000: 929-932

  6. Atmospheric CO2 level affects plants' carbon use efficiency: insights from a 13C labeling experiment on sunflower stands

    Science.gov (United States)

    Gong, Xiaoying; Schäufele, Rudi; Schnyder, Hans

    2015-04-01

    The increase of atmospheric CO2 concentration has been shown to stimulate plant photosynthesis and (to a lesser extent) growth, thereby acting as a possible sink for the additional atmospheric CO2. However, this effect is dependent on the efficiency with which plants convert atmospheric carbon into biomass carbon, since a considerable proportion of assimilated carbon is returned to the atmosphere via plant respiration. As a core parameter for carbon cycling, carbon use efficiency of plants (CUE, the ratio of net primary production to gross primary production) quantifies the proportion of assimilated carbon that is incorporated into plant biomass. CUE has rarely been assessed based on measurements of complete carbon balance, due to methodological difficulties in measuring respiration rate of plants in light. Moreover, foliar respiration is known to be inhibited in light, thus foliar respiration rate is generally lower in light than in dark. However, this phenomenon, termed as inhibition of respiration in light (IRL), has rarely been assessed at the stand-scale and been incorporated into the calculation of CUE. Therefore, how CUE responses to atmospheric CO2 levels is still not clear. We studied CUE of sunflower stands grown at sub-ambient CO2 level (200 μmol mol-1) and elevated CO2 level (1000 μmol mol-1) using mesocosm-scale gas exchange facilities which enabled continuous measurements of 13CO2/12CO2 exchange. Appling steady-state 13C labeling, fluxes of respiration and photosynthesis in light were separated, and tracer kinetic in respiration was analyzed. This study provides the first data on CUE at a mesocosm-level including respiration in light in different CO2 environments. We found that CUE of sunflower was lower at an elevated CO2 level than at a sub-ambient CO2 level; and the ignorance of IRL lead to erroneous estimations of CUE. Variation in CUE at atmospheric CO2 levels was attributed to several mechanisms. In this study, CO2 enrichment i) affected the

  7. A study on the effect of neighboring protons in proton-coupled spin-lattice relaxation of methylene carbon-13 in n-undecane

    CERN Document Server

    Kim, C

    2002-01-01

    Proton coupled carbon-13 relaxation experiment was performed to investigate the effect of vicinal protons on spin-lattice relaxation of methylene carbon-13 in n-nudecane. A BIRD type pulse sequence was employed as a way to check the validity of describing sup 1 sup 3 CH sub 2 moiety as an isolated AX sub 2 spin system. The results show that the presence of vicinal protons exerts substantial influence on the relaxation of methylene carbon-13, indicating that it is not a very good approximation to treat a methylene moiety as an isolated AX sub 2 spin system.

  8. 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.

  9. Concentration and delta13C variation of atmospheric carbon dioxide near car traffic routes

    International Nuclear Information System (INIS)

    Results of CO2 concentration and delta13C measurements in the atmospheric air sampled in Cracow and neighbourhood at the points of different influence of automobil exhaust gases are presented. Observed maximum the CO2 concentration at heavy traffic cross-road reached value 419 ppm while delta13C = -9.2%o. The CO2 concentration and delta13C values show correlation for either four sampling points. In the case of domination natural daily fluctuation of CO2 simple mixing model fits very well. Fluctuations determined by anthropogenic CO2 cannot be described by this model indicating different type of correlation. (author)

  10. 31P and 13C-NMR studies of the phosphorus and carbon metabolites in the halotolerant alga, Dunaliella salina

    International Nuclear Information System (INIS)

    The intracellular phosphorus and carbon metabolites in the halotolerant alga Dunaliella salina adapted to different salinities were monitored in living cells by 31P- and 13C-nuclear magnetic resonance (NMR) spectroscopy. The 13C-NMR studies showed that the composition of the visible intracellular carbon metabolites other than glycerol is not significantly affected by the salinity of the growth medium. The T1 relaxation rates of the 13C-glycerol signals in intact cells were enhanced with increasing salinity of the growth medium, in parallel to the expected increase in the intracellular viscosity due to the increase in intracellular glycerol. The 31P-NMR studies showed that cells adapted to the various salinities contained inorganic phosphate, phosphomonoesters, high energy phosphate compounds, and long chain polyphosphates. In addition, cells grown in media containing up to 1 molar NaCl contained tripolyphosphates. The tripolyphosphate content was also controlled by the availability of inorganic phosphate during cell growth. Phosphate-depleted D. salina contained no detectable tripolyphosphate signal. Excess phosphate, however, did not result in the appearance of tripolyphosphate in 31P-NMR spectra of cells adapted to high (>1.5 molar NaCl) salinities

  11. 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

  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. 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 < 0.15 permil) and accuracy (R2 = 0.9997, i.e. comparison TOC-IRMS and conventional EA-IRMS) were achieved by TOC-IRMS for a broad diversity of DOC solutions. This precision is comparable or even slightly better than that typically reported for EA-IRMS systems, and improves previous techniques for δ13C analysis of DOC. Simultaneously, very good precision was obtained for DOC concentration measurements. Assessment of natural abundance and slightly 13C enriched DOC, a wide range of concentrations (0.2-150 mgC/L) and injection volumes (0.05-3 ml), demonstrated good analytical performance with negligible memory effects, no concentration/volume effects and a wide linearity. Low DOC concentrations (< 2 mgC/L), were correctly analyzed without any pre-concentration. Moreover, TOC-IRMS was successfully applied to analyze DOC from diverse terrestrial, freshwater and marine environments (SD < 0.23 permil). In summary, the TOC

  15. 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

  16. 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.)

  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. Radiocarbon, 13C and tritium in water samples from basaltic aquifers and carbonate aquifers on the island of Oahu, Hawaii

    International Nuclear Information System (INIS)

    Principal fresh water aquifers on the subtropical island of Oahu consist of basaltic rocks that are devoid of fossil carbonate minerals. In southern Oahu fresh water occurs as semi-independent basal lenses which float on salt water and are bounded by sedimentary formations along the coast and in valley bottoms. The latter formations contain carbonate aquifers. Fresh water also occurs in dike compartments located in the central parts of the mountains. The radiocarbon content of groundwater recharge on Oahu is between 96 and 100% modern. The 13C concentration associated with fresh groundwater is between -17 and -19 δ per mille PDB and remains constant while such waters reside in, or travel through, basaltic rock aquifers. Radiocarbon and tritium data on basal waters withdrawn by major pumping stations show these waters to have ages between a few decades and several hundred years. Differences in these ages relate systematically to individual pumping rates of the stations, well depths and local lens thickness. (author)

  19. In situ Raman spectroelectrochemical study of 13C labeled fullerene peapods and double walled carbon nanotubes

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav; Zukalová, Markéta; Dunsch, L.

    2007-01-01

    Roč. 3, č. 10 (2007), s. 1746-1752. ISSN 1613-6810 R&D Projects: GA AV ČR KJB400400601; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : Raman spectroscopy * spectroelectrochemistry * carbon nanotube Subject RIV: CG - Electrochemistry Impact factor: 6.408, year: 2007

  20. 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.

  1. 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

  2. Carbon-13 isotopic selectivity in the infrared multiphoton photolysis of CF2Cl2-O2 mixtures

    International Nuclear Information System (INIS)

    The infrared multiphoton chemistry of CF2Cl2-O2 mixtures has been studied at laser frequencies where the product CF2O is highly enriched in carbon-13 yield. Yield enhancements with no loss of isotopic selectivity are attributed to suppression of radical-atom recombination reactions. It is demonstrated that addition of up to 60 Torr of either excess O2 or N2 suppresses a thermal, non-selective channel important at higher fluences. A selectivity factor greater than 30 is observed for 4 Torr CF2Cl2 in the presence of 80 Torr of oxygen

  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. Temporal δ13C records from bottlenose dolphins (Tursiops truncatus) reflect variation in foraging location and global carbon cycling

    Science.gov (United States)

    Rossman, S. L.; Barros, N. B.; Ostrom, P. H.; Gandhi, H.; Wells, R. S.

    2010-12-01

    With four decades of data on a population of bottlenose dolphins (Tursiops truncatus) resident to Sarasota Bay (SB), The Sarasota Dolphin Research Program offers an unparalleled platform for ground-truthing stable isotope data and exploring bottlenose dolphin ecology in a natural setting. We explored carbon isotope value fidelity to habitat utilization by comparing δ13C data from whole teeth and muscle to the individual dolphin's proclivity towards foraging in seagrass beds based on observational data. We then examined variation in habitat use based on temporal isotope records. Whole tooth protein isotope values do not show a significant correlation with the observed percentage of foraging in seagrass habitat. In contrast, δ13C values from muscle showed a significant positive relationship with the observational data. Differences in the degree of tissue turn over may account for this distinction between tooth and muscle. Dolphin teeth consist of annually deposited layers that are inert once formed. Thus, the isotopic composition of protein in annuli reflect foraging at the time of deposition. In addition to incorporating variation associated with differences in foraging over the lifetime of the individual, whole tooth isotope values are confounded because a disproportionate amount of tooth protein derives from the first few years of life. Given the turnover time of muscle tissue, isotope values reflect diet over the past several months. From 1991 to 2008, muscle δ13C values showed a significant decline, -13.5‰ to -15.1‰.This time period encompasses a state wide net fishing ban (1995) however other factors such as a series of red tide harmful algal blooms, a decline in predators, increases in shallow water boat traffic and an increase in string ray abundance may also contribute to the temporal isotope trend. To examine changes in dolphin foraging habitat further back in time we analyzed the tip of crown of the tooth which records the isotopic signal from the

  5. 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

  6. 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...

  7. Interactions of 13.6-GeV/nucleon 16O and 28Si with carbon, aluminum, and copper

    International Nuclear Information System (INIS)

    Cross sections for forming 24Na and 18F by the interactions of 13.6-GeV/nucleon 16O and 28Si ions with Al and for forming 24Na in 16O interactions with Cu have been measured relative to the cross section for forming 11C from carbon. The results are generally consistent with energy-independent inclusive cross sections (limiting fragmentation) for heavy ions between ∼2 and 13.6 GeV/nucleon. However, comparison of the heavy-ion data with those for high-energy protons indicates a significantly weaker dependence on projectile size than that predicted by the factorization hypothesis for σC(11C), σAl(18F), and σAl(24Na). The dependence is slightly stronger in the case of σCu(24Na)

  8. 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}.

  9. 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

  10. In vivo studies of pyridine nucleotide metabolism in Escherichia coli and Saccharomyces cerevisiae by carbon-13 NMR spectroscopy

    International Nuclear Information System (INIS)

    Pyridine nucleotide metabolism has been studied in vivo in a prokaryotic (Escherichia coli) and a eukaryotic (Saccharomyces cerevisiae) system cultured in a medium containing carbon-13-labeled nicotinic acid, followed by NMR detection of the labeled organisms. Chemical exchange between oxidized and reduced nucleotides is found to be sufficiently slow on the NMR time scale to permit the observation of separate resonances corresponding to each redox state. The possibility of significant exchange broadening of reduced pyridine nucleotide resonances under some conditions was further evaluated based on comparative NMR studies utilizing organisms cultured in the presence of either [2-13C]nicotinate or [5-13C]nicotinate. Based on these experiments, it was concluded that broadening as a consequence of intermediate exchange is not significant. Although it was initially anticipated that the carbon-13 resonances arising from the di- and triphosphopyridine nucleotide pools could not be distinguished, the absence of observable resonances corresponding to reduced nucleotides in oxygenated yeast and E. coli cells suggests that the NMR method is fairly specific for determining the redox status of the diphosphopyridine nucleotide pool. Studies of the effects of a variety of perturbations including variation of the oxygen supply, addition of ethanol, and addition of the oxidative phosphorylation uncoupler dinitrophenol have been carried out. Dramatic differences in the response of the catabolic reduction charge, CRC = [NADH]/[NADH] + [NAD+], between the yeast and E. coli cells are observed. The CRC values for the yeast undergo large changes in response to these perturbations which are not observed for the bacterial cells. 52 references, 9 figures, 2 tables

  11. 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

  12. 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.

  13. All-Carbon [3+3] Oxidative Annulations of 1,3-Enynes by Rhodium(III)-Catalyzed C–H Functionalization and 1,4-Migration**

    Science.gov (United States)

    Burns, David J; Best, Daniel; Wieczysty, Martin D; Lam, Hon Wai

    2015-01-01

    1,3-Enynes containing allylic hydrogens cis to the alkyne function as three-carbon components in rhodium(III)-catalyzed, all-carbon [3+3] oxidative annulations to produce spirodialins. The proposed mechanism of these reactions involves the alkenyl-to-allyl 1,4-rhodium(III) migration. PMID:26224377

  14. 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

  15. 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.

  16. Spherical cauliflower-like carbon dust formed by interaction between deuterium plasma and graphite target and its internal structure

    International Nuclear Information System (INIS)

    Simulated experiments to produce carbon dust particles with cauliflower structure have been performed in a liner plasma device, NAGDIS-II by exposing high density deuterium plasma to a graphite sample (IG-430U). Formation of carbon dust depends on the surface temperature and the incident ion energy. At a surface temperature 600-700 K, a lot of isolated spherical dust particles are observed on the graphite target. The internal structure of an isolated dust particle was observed with Focused Ion Beam (FIB) system and Transmission Electron Microscope (TEM) in detail. FIB analysis clearly shows there exist honey-combed cell structure with thin carbon walls in the dust particle and the dust particle grows from the graphite surface. TEM image also shows that the dust particle is made of amorphous carbon with crystallized grains with diameters of 10-50 nm.

  17. 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

  18. 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...

  19. 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

  20. Aspartate beta-decarboxylase from Alcaligenes faecalis: carbon-13 kinetic isotope effect and deuterium exchange experiments

    International Nuclear Information System (INIS)

    The authors have measured the 13C kinetic isotope effect at pH 4.0, 5.0, 6.0, and 6.5 and in D2O at pH 5.0 and the rate of D-H exchange of the alpha and beta protons of aspartic acid in D2O at pH 5.0 for the reaction catalyzed by the enzyme aspartate beta-decarboxylase from Alcaligenes faecalis. The 13C kinetic isotope effect, with a value of 1.0099 +/- 0.0002 at pH 5.0, is less than the intrinsic isotope effect for the decarboxylation step, indicating that the decarboxylation step is not entirely rate limiting. The authors have been able to estimate probable values of the relative free energies of the transition states of the enzymatic reaction up to and including the decarboxylation step from the 13C kinetic isotope effect and the rate of D-H exchange of alpha-H. The pH dependence of the kinetic isotope effect reflects the pKa of the pyridine nitrogen of the coenzyme pyridoxal 5'-phosphate but not that of the imine nitrogen. A mechanism is proposed for the exchange of aspartate beta-H that is consistent with the stereochemistry suggested earlier

  1. Aspartate beta-decarboxylase from Alcaligenes faecalis: carbon-13 kinetic isotope effect and deuterium exchange experiments

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, R.M.; O' Leary, M.H.

    1985-03-26

    The authors have measured the /sup 13/C kinetic isotope effect at pH 4.0, 5.0, 6.0, and 6.5 and in D/sub 2/O at pH 5.0 and the rate of D-H exchange of the alpha and beta protons of aspartic acid in D/sub 2/O at pH 5.0 for the reaction catalyzed by the enzyme aspartate beta-decarboxylase from Alcaligenes faecalis. The /sup 13/C kinetic isotope effect, with a value of 1.0099 +/- 0.0002 at pH 5.0, is less than the intrinsic isotope effect for the decarboxylation step, indicating that the decarboxylation step is not entirely rate limiting. The authors have been able to estimate probable values of the relative free energies of the transition states of the enzymatic reaction up to and including the decarboxylation step from the /sup 13/C kinetic isotope effect and the rate of D-H exchange of alpha-H. The pH dependence of the kinetic isotope effect reflects the pKa of the pyridine nitrogen of the coenzyme pyridoxal 5'-phosphate but not that of the imine nitrogen. A mechanism is proposed for the exchange of aspartate beta-H that is consistent with the stereochemistry suggested earlier.

  2. Hydrological budget, carbon sources and biogeochemical processes in Lac Pavin (France): Constraints from δ18O of water and δ13C of dissolved inorganic carbon

    International Nuclear Information System (INIS)

    Lac Pavin (French Massif Central) is a permanently stratified lake: the upper water layers (mixolimnion, from 0 to 60 m depth) are affected by seasonal overturns, whereas the bottom water layers (monimolimnion, from 60 to 90 m depth) remain isolated and are never mixed. Hence, they are capable of storing important quantities of dissolved gases, mainly CO2. With the aim of better constraining the water balance and of gaining new insights into the carbon cycle of Lac Pavin, an isotopic approach is used. The δ18OH2O profiles lead the authors to give a new evaluation of the evaporation flow rate (8 L s-1), and to propose and characterize two sub-surface springs. The sub-surface spring located at the bottom of the lake can be deduced from the 1% isotopic difference between the upper water layers (mean δ18OH2O value: -7.3 per mille ) and the bottom water layers (δ18OH2O=-8.4 per mille ). It is argued that this sub-surface spring has isotopic and chemical characteristics similar to those of the magmatic CO2-rich spring (i.e. Fontaine Goyon, δ18OH2O=-9.4 per mille ), and we calculate its flow rate of 1.6 L s-1. The second sub-surface spring is located around 45 m depth, with a composition close to those of the water surface streams (δ18OH2O13CDIC ∼ +7 per mille ) and 2/3 from the magmatic CO2-rich spring (δ13CDIC ∼ -5 per mille ). Above 80 m depth, the variations in DIC concentrations (ranging from 0.5 to 10 mM) and δ13CDIC values (ranging from -6.5 per mille to 4.4 per mille ) are partly explained by the usual methanotrophy, organic matter oxidation, photosynthesis and CO2 equilibrium with atmosphere. The unusually high δ13CDIC values in the upper water layers (ranging from -6 per mille to 0 per mille ) compared to the expected δ13CDIC values assuming only organic matter oxidation, demonstrate the leakage of 13C-enriched DIC from the bottom water layers of Lac Pavin (δ13CDIC values ranging from -5 per mille to 3 per mille )

  3. 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.

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

    Science.gov (United States)

    Makireddi, Sai; Balasubramaniam, Krishnan

    2016-02-01

    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.

  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. 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.

  7. 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.

  8. 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

  9. Processing of particulate organic carbon associated with secondary-treated pulp and paper mill effluent in intertidal sediments: a 13C pulse-chase experiment.

    Science.gov (United States)

    Oakes, Joanne M; Ross, Donald J; Eyre, Bradley D

    2013-01-01

    To determine the benthic transformation pathways and fate of carbon associated with secondary-treated pulp and paper mill (PPM) effluent, (13)C-labeled activated sludge biomass (ASB) and phytoplankton (PHY) were added, separately, to estuarine intertidal sediments. Over 28 days, (13)C was traced into sediment organic carbon, fauna, seagrass, bacteria, and microphytobenthos and into fluxes of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) from inundated sediments, and carbon dioxide (CO2(g)) from exposed sediments. There was greater removal of PHY carbon from sediments (~85% over 28 days) compared to ASB (~75%). Although there was similar (13)C loss from PHY and ASB plots via DIC (58% and 56%, respectively) and CO2(g) fluxes (<1%), DOC fluxes were more important for PHY (41%) than ASB (12%). Faster downward transport and loss suggest that fauna prefer PHY, due to its lability and/or toxins associated with ASB; this may account for different carbon pathways. Secondary-treated PPM effluent has lower oxygen demand than primary-treated effluent, but ASB accumulation may contribute to sediment anoxia, and respiration of ASB and PHY-derived DOC may make the water column more heterotrophic. This highlights the need to optimize secondary-treatment processes to control the quality and quantity of organic carbon associated with PPM effluent. PMID:24261917

  10. 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

  11. 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...

  12. Bone marrow-derived CD13+ cells sustain tumor progression: A potential non-malignant target for anticancer therapy

    OpenAIRE

    Dondossola, Eleonora; Corti, Angelo; Sidman, Richard L.; Arap, Wadih; Pasqualini, Renata

    2014-01-01

    Non-malignant cells found within neoplastic lesions express alanyl (membrane) aminopeptidase (ANPEP, best known as CD13), and CD13-null mice exhibit limited tumor growth and angiogenesis. We have recently demonstrated that a subset of bone marrow-derived CD11b+CD13+ myeloid cells accumulate within neoplastic lesions in several murine models of transplantable cancer to promote angiogenesis. If these findings were confirmed in clinical settings, CD11b+CD13+ myeloid cells could become a non-mali...

  13. Targeting CD13 (aminopeptidase-N) in turn downregulates ADAM17 by internalization in acute myeloid leukaemia cells

    OpenAIRE

    Bouchet, Sandrine; TANG, RUOPING; Fava, Fanny; Legrand, Ollivier; Bauvois, Brigitte

    2014-01-01

    Secreted matrix metalloproteinases (MMP)-2 and MMP-9 and membrane-anchored aminopeptidase-N/CD13 are abnormally expressed in human acute myeloid leukaemia (AML). We previously showed that CD13 ligation by anti-CD13 monoclonal antibodies can induce apoptosis in AML cells. Here, we assessed ADAM17 expression in primary blood blasts CD13+CD33+ from patients with AML. Primary AML cells expressed ADAM17 transcript and its surface expression was higher in subtype M4 (myelomonocytic) and M5 (monocyt...

  14. Carbonic anhydrase inhibitors: Design, synthesis and structural characterization of new heteroaryl-N-carbonylbenzenesulfonamides targeting druggable human carbonic anhydrase isoforms

    Czech Academy of Sciences Publication Activity Database

    Buemi, M. R.; De Luca, L.; Ferro, S.; Bruno, E.; Ceruso, M.; Supuran, C. T.; Pospíšilová, K.; Brynda, Jiří; Řezáčová, Pavlína; Gitto, R.

    2015-01-01

    Roč. 102, Sep 18 (2015), s. 223-232. ISSN 0223-5234 Institutional support: RVO:61388963 Keywords : human carbonic anhydrase * isoquinoline * quinoline * X-ray * molecular docking Subject RIV: CE - Biochemistry Impact factor: 3.447, year: 2014

  15. 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

  16. 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.

  17. 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

  18. Orbital plasma keyhole welding of 12--13% Cr low carbon martensitic line pipe steels and weld joint corrosion properties

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmeister, H.; Dietrich, S. [Univ. der Bundeswehr Hamburg (Germany); Tystad, M.; Knagenhjelm, H.O.; Andersen, T.R. [Norsk Hydro A/S Porsgrunn (Norway). Forskningssenteret

    1995-10-01

    Based on requirements for more economical pipe laying procedures in the oil and gas industry, the potential of the orbital plasma keyhole process for welding of 12--13% Cr martensitic low carbon steels together with resulting hardness and corrosion properties is investigated. As a result, downhill orbital welding speeds up to 6--7 mm/s at 6--10 mm wall thickness are achieved. For hardness reduction, local postweld heating of 600--700 C at up to 10 min was required. Pitting corrosion resistance of the weld joints was reduced by welding but could be restored by postweld heating above 750--800 C, which, however, might produce hardness levels not satisfying NACE requirements due to formation of untempered martensite.

  19. 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

  20. Carbonic anhydrase inhibitors: Design, synthesis and structural characterization of new heteroaryl-N-carbonylbenzenesulfonamides targeting druggable human carbonic anhydrase isoforms

    Czech Academy of Sciences Publication Activity Database

    Buemi, M. R.; De Luca, L.; Ferro, S.; Bruno, E.; Ceruso, M.; Supuran, C. T.; Pospíšilová, K.; Brynda, Jiří; Řezáčová, Pavlína; Gitto, R.

    2015-01-01

    Roč. 102, SEP 18 (2015), s. 223-232. ISSN 0223-5234 R&D Projects: GA ČR GA15-05677S Grant ostatní: Fondo di Ateneo per la Ricerca (PRA)(IT) ORME09SPNC Institutional support: RVO:68378050 Keywords : Human carbonic anhydrase * Isoquinoline * Quinoline * X-ray * Molecular docking Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.447, year: 2014

  1. Carbon-13 nuclear magnetic resonance spectroscopic characterization of humic substances from municipal refuse decomposing in a landfill

    International Nuclear Information System (INIS)

    Municipal refuse was disposed of in simulated landfills and left for periods of more than 20 months. Three different 40 m3 systems of disposals were studied, namely (i) where the refuse was compacted, (ii) where it was mixed with sewage sludge and left uncompacted, and (iii) where it was compacted with sewage sludge. At 2, 6, 12 and 20 months, the humic substances were extracted from each system, purified, and characterised by cross-polarisation 13C NMR spectroscopy with 'magic-angle' sample spinning. The areas under the various signals were related to carbon percentages in different structural categories. The aromaticity of the humic acids increased with time of decomposition; those from refuse mixed with sewage sludge were particularly high in phenolic content. A signal at 174 p.p.m., assigned primarily to secondary amide linkages, reached maximum strength after 6 to 12 months decomposition. The carbohydrate contents of the humic acids showed only small variations as decomposition progressed. Polymethylene chains in lipids, particularly for the uncompacted system, accounted for a diminishing fraction of total carbon as time of refuse disposal increased. The spectrum of a soil humic acid showed features similar to those observed in spectra of humic acids derived from refuse, but the signals were less well resolved. 19 refs.; 8 figs.; 3 tabs

  2. 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

  3. 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

  4. 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.

  5. 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

  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. 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

  8. Walking alone? How the UK’s carbon targets compare with its competitors’

    OpenAIRE

    Bassi, Samuela; Fankhauser, Samuel; Green, Fergus; Nachmany, Michal

    2014-01-01

    Headline issue: The UK Government is reviewing the fourth carbon budget for the period 2023-27. The Committee on Climate Change has recommended that the budget, which was originally legislated in 2011, should remain unchanged. That is, the UK should plan to cut its greenhouse gas emissions by 50 per cent, relative to 1990 levels, by 2025 — the midpoint of the fourth carbon budget period. The fourth carbon budget has been criticised for committing the UK to a unilateral, and potentially econo...

  9. Cyanobacteria as a carbon source for zooplankton in eutrophic Lake Taihu, China, measured by 13C labeling and fatty acid biomarkers

    OpenAIRE

    de Kluijver, A.; Yu, J.L.; Houtekamer, M.; Middelburg, J. J.; Liu, Z.W.

    2012-01-01

    Using a combined stable-isotope and fatty-acid approach, we examined carbon-transfer routes from the cyanobacterium Microcystis to zooplankton in eutrophic Lake Taihu, China. Microcystis is generally considered poor food for zooplankton, and we hypothesized that most Microcystis carbon flows to zooplankton via dissolved organic matter (DOM)-bacteria and detritus-bacteria pathways rather than via direct grazing. The hypothesis was tested by analyzing C-13 isotopes at natural abundance in field...

  10. 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

  11. 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].

  12. Preparation method of carbon aerogels as the target materials of laser inertial confinement fusion

    International Nuclear Information System (INIS)

    Resorcinol-formaldehyde (RF) aerogels with high RC ratio (molar ratio of resorcinol to catalyst) are prepared by using sol-gel process. They can be dried at ambient conditions by solvent substitution. Carbon aerogels are formed by pyrolyzing the RF aerogels, and the grain and pore size, density and specific surface area of aerogels can be controlled by adjusting the RC ratio and the concentration of resorcinol. The micro-structure of the porous carbon aerogels is measured by SEM and BET

  13. 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.

  14. 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.

  15. Carbon flow and trophic structure of an Antarctic coastal benthic community as determined by δ 13C and δ 15N

    Science.gov (United States)

    Gillies, C. L.; Stark, J. S.; Johnstone, G. J.; Smith, S. D. A.

    2012-01-01

    Stable isotopes of carbon and nitrogen were used to determine the different carbon pathways and trophic assemblages amongst coastal benthic fauna of the Windmill Islands, East Antarctica. Macroalgae, pelagic POM, sediment POM and sea ice POM had well-separated δ 13C signatures, which ranged from -36.75‰ for the red alga Phyllophora antarctica, to -10.35‰ for sea ice POM. Consumers were also well separated by δ 13C, ranging from -21.42‰ for the holothurian Staurocucumis sp. up to -7.47‰ for the urchin Sterechinus neumayeri. Analysis of δ 13C and δ 15N revealed distinct groups for suspension feeders, grazer/herbivores and deposit feeders, whilst predators and predator/scavengers showed less grouping. Consumers spanned a δ 15N range of 8.71‰, equivalent to four trophic levels, although δ 15N ratios amongst consumers were continuous, rather than grouped into discrete trophic levels. The study has built a trophic model for the Windmill Islands and summarises three main carbon pathways utilised by the benthos: (1) pelagic POM; (2) macroalgae/epiphytic/benthic diatoms and (3) sediment POM/benthic diatoms. The movement of carbon within the coastal benthic community of the Windmill Islands is considered complex, and stable isotopes of carbon and nitrogen were valuable tools in determining specific feeding guilds and in tracing carbon flow, particularly amongst lower-order consumers.

  16. A G-protein activation cascade from Arl13B to Arl3 and implications for ciliary targeting of lipidated proteins.

    Science.gov (United States)

    Gotthardt, Katja; Lokaj, Mandy; Koerner, Carolin; Falk, Nathalie; Gießl, Andreas; Wittinghofer, Alfred

    2015-01-01

    Small G-proteins of the ADP-ribosylation-factor-like (Arl) subfamily have been shown to be crucial to ciliogenesis and cilia maintenance. Active Arl3 is involved in targeting and releasing lipidated cargo proteins from their carriers PDE6δ and UNC119a/b to the cilium. However, the guanine nucleotide exchange factor (GEF) which activates Arl3 is unknown. Here we show that the ciliary G-protein Arl13B mutated in Joubert syndrome is the GEF for Arl3, and its function is conserved in evolution. The GEF activity of Arl13B is mediated by the G-domain plus an additional C-terminal helix. The switch regions of Arl13B are involved in the interaction with Arl3. Overexpression of Arl13B in mammalian cell lines leads to an increased Arl3·GTP level, whereas Arl13B Joubert-Syndrome patient mutations impair GEF activity and thus Arl3 activation. We anticipate that through Arl13B's exclusive ciliary localization, Arl3 activation is spatially restricted and thereby an Arl3·GTP compartment generated where ciliary cargo is specifically released. PMID:26551564

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

    Science.gov (United States)

    Salmon, Yann; Buchmann, Nina; Barnard, Romain L

    2016-01-01

    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. PMID:27010947

  18. 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.

  19. 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

  20. 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

  1. 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

  2. Carbon fiber composite targets for nuclear fusion technology: a focused ion beam/scanning electron microscope investigation.

    Science.gov (United States)

    Ghezzi, F; Magni, S; Milani, M; Tatti, F

    2007-01-01

    Carbon fiber composite (CFC) targets are investigated by a focused ion beam/scanning electron microscope (FIB/SEM) in a joint project aiming at the development of robust divertors in the International Thermonuclear Experimental Reactor (ITER). These mockups are exposed to a plasma that simulates the off-normal thermal loads foreseen for ITER and display a rich, puzzling impact scenario. Morphological elements are identified at the exposed surface and beneath it, and are examined in order to point out the relevant processes involved. Each technique adopted is discussed and evaluated. PMID:18200678

  3. Stable carbon isotope ratio (delta /sup 13/C) of shallow marine bottom sediment as evidence of pollution in Manora channel, Karachi, Pakistan

    International Nuclear Information System (INIS)

    Marine sediments are one of the endpoints for domestic /industrial contaminants from land based sources and provide an archive for tracing pollution record. Contaminated sediment is a significant environmental problem affecting many marine ecosystem. In the present study sediment samples from Manora Channel/Karachi harbour were analyzed for stable isotope composition of inorganic and organic carbon fractions (measured as (delta /sup 13/C) to estimate the land based terrestrial organic matter in the Manora Channel. The principle of this application lies in the fact that delta /sup 13/C values of inorganic carbon (mineral fractions such as calcite, aragonite, dolomite) differs vastly from that of the organic carbon fraction of domestic and/or industrial origin in the sediments. Relatively more depleted delta /sup 13/C (organic) values ranging between - 30.65 to -19.27 - PDB for the organic carbon fraction were found in the Layari river outfall zone. In Manora channel mains enriched values (delta /sup 13/C was found in sediment of Manora lighthouse (-5.0 - PDB) and Pakistan Naval Academy (-11.76 - PDB) while in same zones depleted values of (delta /sup 13/C was found in Bhabba island (-27.31 - PDB), Bhit Island (-26.13 PDB) and Boat Club area (-23.08 PDB) indicating impact of domestic sewage added to the Manora channel from surrounding Islands. (delta /sup 13/C (inorganic) fraction of sediment follow similar trend. In conclusion, this study indicates that the bottom sediments of Karachi Harbour and Layari river outfall zones are mainly polluted with organic waste of domestic origin derived from Layari river. (author)

  4. 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...

  5. Magic angle spinning carbon-13 NMR of tobacco mosaic virus. An application of the high-resolution solid-state NMR spectroscopy to very large biological systems.

    OpenAIRE

    Hemminga, M A; Veeman, W.S.; Hilhorst, H.W.M.; Schaafsma, T J

    1981-01-01

    Magic angle spinning 13C NMR was used to study tobacco mosaic virus (TMV) in solution. Well-resolved 13C NMR spectra were obtained, in which several carbon resonances of amino acids of the TMV coat protein subunits that are not observable by conventional high-resolution NMR spectroscopy can be designed. RNA resonance were absent, however, in the magic angle spinning 13C NMR spectra. Since three different binding sites are available for each nucleotide of the RNA, this is probably due to a lin...

  6. Carbonic anhydrase inhibitors: Design, synthesis and structural characterization of new heteroaryl-N-carbonylbenzenesulfonamides targeting druggable human carbonic anhydrase isoforms.

    Science.gov (United States)

    Buemi, Maria Rosa; De Luca, Laura; Ferro, Stefania; Bruno, Elvira; Ceruso, Mariangela; Supuran, Claudiu T; Pospíšilová, Klára; Brynda, Jiří; Řezáčová, Pavlína; Gitto, Rosaria

    2015-09-18

    A set of heteroaryl-N-carbonylbenzenesulfonamides has been designed, synthesized, and screened as inhibitors of human carbonic anhydrases (hCAs). The new sulfonamide derivatives were tested against hCA I, hCA II, hCA VII, hCA IX, and hCA XII isoforms using acetazolamide (AAZ, 1) and topiramate (TPM, 2) as reference compounds. Six compounds were low nanomolar inhibitors of tumor-associated hCA IX isoform (Ki values 1500 for compound 5c). Thus, these compounds can offer the opportunity to highlight the interactions preventing the inhibition of hCA VII mainly expressed in central nervous system. Thereby, we used structural and computational techniques to study in depth the interaction with hCAs. In an effort to confirm the inhibitory action we determined crystal structures of five selected heteroaryl-N-carbonylbenzenesulfonamides (4a, 4b, 4e, 5c, and 5e) in complex with hCA II. Moreover, to explore the lack of inhibitory effects of selected compounds (e.g.4b and 5c) we also performed docking studies into hCA VII catalytic site. PMID:26276436

  7. Microbially mediated carbon cycling as a control on the δ 13C of sedimentary carbon in eutrophic Lake Mendota (USA): new models for interpreting isotopic excursions in the sedimentary record

    Science.gov (United States)

    Hollander, David J.; Smith, Michael A.

    2001-12-01

    An isotopic study of various carbon phases in eutrophic Lake Mendota (Wisconsin, USA) indicates that the δ 13C composition of sedimentary organic and inorganic carbon has become more negative in response to increasing microbially mediated carbon cycling and processes associated with the intensification of seasonal and long-term eutrophication. Progressive increases in the contributions of isotopically depleted chemoautotrophic and methanotrophic biomass (reflected in the -40 to -90‰ values of hopanols and FAMES), attributed to seasonal and long-term increases in production and expansion of the anaerobic water mass, accounts for carbon isotopic trends towards depleted δ 13C values observed in both seasonal varves and over the past 100 years. Changes in the intensities of certain microbial processes are also evident in the sedimentary geochemical record. During the period of most intense cultural eutrophication, when the oxic-anoxic interface was located close to the surface, methanogenesis/methanotrophy and the oxidation of biogenic methane increased to the extent that significant quantities of 13C-depleted CO 2 were added into the epilimnion. This depleted CO 2 was subsequently utilized by phytoplankton and incorporated into CaCO 3 during biogenically induced calcite precipitation. A comparative study between eutrophic Lakes Mendota and Greifen, further indicate that the extent of nutrient loading in the epilimnion determines whether the δ 13C record of sedimentary organic carbon reflects intensification of microbial processes in the hypolimnion and sediments, or changes in the primary productivity in the photic zone. From this comparison, a series of eutrophication models are developed to describe progressive transitions through thresholds of microbial and eukaryotic productivity and their influence on the δ 13C record of sedimentary carbon. With increasing eutrophication, the models initially predict a negative and then a subsequent positive carbon isotopic

  8. 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

  9. Carbon-13 kinetic isotope effect and its temperature dependence in the decarboxylation of lactic acid of natural isotopic composition with aqueous sulphuric acid

    International Nuclear Information System (INIS)

    Carbon-13 kinetic isotope effect in the decarboxylation of lactic acid of natural isotopic composition in sulphuric acid diluted with water in M(H2O)/M(H2SO4) molar ratio equal to 2.2 has been studied in the temperature range 80-130 C and found to be normal. The absolute values and the temperature dependence of the experimental 13C-K.I.E. are in agreement with the absolute values and the temperature dependence of the theoretical 13C-K.I.E. calculated under the assumption that one frequency corresponding to the carbon-oxygen bound broken in the decarboxylation reaction is lost in the course of activation of lactic acid molecules. The chemical side reactions leading to the abnormal temperature dependence of the carbon-13 and carbon-14 isotope fractionation, observed in the course of decarboxylation of lactic acid in concentrated sulphuric acid, have been suggested. (author). 11 refs, 1 fig., 1 tab

  10. 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.

  11. The sustainability challenge of meeting carbon dioxide targets in Europe by 2020

    International Nuclear Information System (INIS)

    Following the Kyoto Protocol, the European Union obligated itself to lower its greenhouse gas (GHG) emissions 20% below their 1990 level, by the year 2020. Carbon dioxide is the major GHG. To fulfil this obligation, the nations must meet the sustainability challenge of countering rising population plus affluence with the dematerialization of less energy per GDP plus the decarbonization of less carbon per energy. To test the feasibility of meeting the challenge, we analysed carbon dioxide emission during 1993-2004. Although emissions in the entire Union grew only by an average of 0.31% per year, emissions and their drivers varied markedly among the 27 member states. Dematerialization and decarbonization did occur, but not enough to offset the slight population growth plus rapidly increasing affluence. To fulfil its obligation in the next 12 years, the EU27 would have to counter its increasing population and affluence by a combined dematerialization and decarbonization 1.9-2.6 times faster than during 1993-2004. Hence, fulfilling its obligation by addressing fossil carbon emissions alone is very unlikely

  12. The sustainability challenge of meeting carbon dioxide targets in Europe by 2020

    International Nuclear Information System (INIS)

    Following the Kyoto Protocol, the European Union obligated itself to lower its greenhouse gas (GHG) emissions 20% below their 1990 level, by the year 2020. Carbon dioxide is the major GHG. To fulfil this obligation, the nations must meet the sustainability challenge of countering rising population plus affluence with the dematerialization of less energy per GDP plus the decarbonization of less carbon per energy. To test the feasibility of meeting the challenge, we analysed carbon dioxide emission during 1993-2004. Although emissions in the entire Union grew only by an average of 0.31% per year, emissions and their drivers varied markedly among the 27 member states. Dematerialization and decarbonization did occur, but not enough to offset the slight population growth plus rapidly increasing affluence. To fulfil its obligation in the next 12 years, the EU27 would have to counter its increasing population and affluence by a combined dematerialization and decarbonization 1.9-2.6 times faster than during 1993-2004. Hence, fulfilling its obligation by addressing fossil carbon emissions alone is very unlikely. (author)

  13. 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

  14. Single-walled carbon nanotubes disturbed the immune and metabolic regulation function 13-weeks after a single intratracheal instillation.

    Science.gov (United States)

    Park, Eun-Jung; Hong, Young-Shick; Lee, Byoung-Seok; Yoon, Cheolho; Jeong, Uiseok; Kim, Younghun

    2016-07-01

    Due to their unique physicochemical properties, the potential health effects of single-walled carbon nanotubes (SWCNTs) have attracted continuous attention together with their extensive application. In this study, we aimed to identify local and systemic health effects following pulmonary persistence of SWCNTs. As expected, SWCNTs remained in the lung for 13 weeks after a single intratracheal instillation (50, 100, and 200μg/kg). In the lung, the total number of cells and the percentages of lymphocytes and neutrophils significantly increased at 200μg/kg compared to the control, and the Th1-polarized immune response was induced accompanying enhanced expression of tissue damage-related genes and increased release of chemokines. Additionally, SWCNTs enhanced the expression of antigen presentation-related proteins on the surface of antigen-presenting cells, however, maturation of dendritic cells was inhibited by their persistence. As compared to the control, a significant increase in the percentage of neutrophils and a remarkable decrease of BUN and potassium level were observed in the blood of mice treated with the highest dose. This was accompanied by the down-regulation of the expression of antigen presentation-related proteins on splenocytes. Moreover, protein and glucose metabolism were disturbed with an up-regulation of fatty acid β-oxidation. Taken together, we conclude that SWCNTs may induce adverse health effects by disturbing immune and metabolic regulation functions in the body. Therefore, careful application of SWCNTs is necessary for the enforcement of safety in nano-industries. PMID:27078092

  15. Two diamictites, two cap carbonates, two δ13C excursions, two rifts: The Neoproterozoic Kingston Peak Formation, Death Valley, California

    Science.gov (United States)

    Prave, A. R.

    1999-04-01

    Stratigraphic mapping of the Neoproterozoic glaciogenic Kingston Peak Formation (Death Valley, California) provides evidence for two temporally discrete extensional deformation episodes. These episodes are bracketed by the Sourdough Limestone and Noonday Dolomite, the facies characteristics and δ13C data (ranging between 2.15 and -2.56‰ and -1.88 and -4.86‰, respectively) of which make them equivalent to Sturtian and Varangian age cap carbonates, respectively. This constrains the two extensional episodes along the southwestern margin of Laurentia to ca. 700 Ma and ca. 600 Ma. These observations and data show that the field evidence for mid-Neoproterozoic breakup and the predictions from tectonic subsidence curves for a latest Neoproterozoic breakup are both correct. Thus, Neoproterozoic plate reconstructions must account for two discrete rift episodes separated by 100 m.y. or more. Confining rifting to within the Kingston Peak Formation thereby places the younger Proterozoic rocks of the southwestern Great Basin in the rift to drift tectonic phase.

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

    Science.gov (United States)

    Weng, Shao-Wen; Wei, Yu-Ching; Eng, Hock-Liew; Huang, Wan-Ting

    2015-01-01

    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-free survival

  17. 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

  18. 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) and a...... heavily degraded Artemisia frigida dominated community (1.3% organic matter content). Dung was collected from sheep either fed on L. chinensis (C3 plant with δ13C = -26.8‰; dung δ13C = -26.2‰) or Cleistogenes squarrosa (C4 plant with δ13C = -14.6‰; dung δ13C = -15.7‰). Fresh C3 and C4 sheep dung was mixed...

  19. 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

  20. 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.

  1. 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

  2. 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...

  3. Backbone dynamics of a model membrane protein: assignment of the carbonyl carbon 13C NMR resonances in detergent-solubilized M13 coat protein

    International Nuclear Information System (INIS)

    The major coat protein of the filamentous bacteriophage M13 is a 50-residue amphiphilic polypeptide which is inserted, as an integral membrane-spanning protein, in the inner membrane of the Escherichia coli host during infection. 13C was incorporated biosynthetically into a total of 23 of the peptide carbonyls using labeled amino acids (alanine, glycine, lysine, phenylalanine, and proline). The structure and dynamics of carbonyl-labeled M13 coat protein were monitored by 13C nuclear magnetic resonance (NMR) spectroscopy. Assignment of many resonances was achieved by using protease digestion, pH titration, or labeling of the peptide bond with both 13C and 15N. The carbonyl region of the natural-abundance 13C NMR spectrum of M13 coat protein in sodium dodecyl sulfate solution shows approximately eight backbone carbonyl resonances with line widths much narrower than the rest. Three of these more mobile residues correspond to assigned peaks (glycine-3, lysine-48, and alanine-49) in the individual amino acid spectra, and another almost certainly arises from glutamic acid-2. A ninth residue, alanine-1, also gives rise to a very narrow carbonyl resonance if the pH is well above or below the pK/sub a/ of the terminal amino group. These data suggest that only about four residues at either end of the protein experience large-amplitude spatial fluctuations; the rest of the molecule is essentially rigid on the time scale of the overall rotational tumbling of the protein-detergent complex. The relative exposure of different regions of detergent-bound protein was monitored by limited digestion with proteinase K. Comparable spectra and digestion patterns were obtained when the protein was solubilized in sodium deoxycholate, suggesting that the coat protein binds both amphiphiles in a similar fashion

  4. Two episodes of 13C-depletion in organic carbon in the latest Permian: Evidence from the terrestrial sequences in northern Xinjiang, China

    Science.gov (United States)

    Cao, Changqun; Wang, Wei; Liu, Lujun; Shen, Shuzhong; Summons, Roger E.

    2008-06-01

    New analyses reveal two intervals of distinctly lower δ13C values in the terrestrial organic matter of Permian-Triassic sequences in northern Xinjiang, China. The younger negative δ13C org spike can be correlated to the conspicuous and sharp δ13C drops both in carbonate carbon and organic carbon near the Permian-Triassic event boundary (PTEB) in the marine section at Meishan. The geochemical correlation criteria are accompanied by a magnetic susceptibility pulse and higher abundances of distinctive, chain-like organic fossil remains of Reduviasporonites. The older negative δ13C org spike originates within a latest Permian regression. Significant changes in organic geochemical proxies are recorded in the equivalent interval of the marine section at Meishan. These include relatively higher concentrations of total organic carbon, isorenieratane, C 14-C 30 aryl isoprenoids and lower ratios of pristane/phytane that, together, indicate the onset of anoxic, euxinic and restricted environments within the photic zone. The massive and widespread oxidation of buried organic matter that induced these euxinic conditions in the ocean would also result in increased concentrations of 13C-depleted atmospheric CO 2. The latest Permian environmental stress marked by the older negative δ13C org episode can be correlated with the distinct changeover of ostracod assemblages and the occurrences of morphological abnormalities of pollen grains. These observations imply that biogeochemical disturbance was manifested on the land at the end of the Permian and that terrestrial organisms responded to it before the main extinction of the marine fauna.

  5. 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

  6. Gastric hyperplasia in mice with targeted disruption of the carbonic anhydrase gene Car9

    Czech Academy of Sciences Publication Activity Database

    Ortová-Gut, M.; Parkkila, S.; Vernerová, Z.; Rohde, E.; Závada, Jan; Hoecker, M.; Pastorek, J.; Karttunen, T.; Gibadulinová, A.; Závadová, Zuzana; Knobeloch, K. P.; Wiedenmann, B.; Svoboda, Jan; Horák, I.; Pastoreková, S.

    2002-01-01

    Roč. 2002, č. 123 (2002), s. 1889-1903. ISSN 0016-5085 Institutional research plan: CEZ:AV0Z5052915 Keywords : Transcription factor FKH6 * parietal-cells * mn/ca-IX Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 13.440, year: 2002

  7. 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...

  8. 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...

  9. Synchronous negative carbon isotope shifts in marine and terrestrial biomarkers at the onset of the early Aptian oceanic anoxic event 1a: Evidence for the release of 13C-depleted carbon into the atmosphere

    Science.gov (United States)

    van Breugel, Yvonne; Schouten, Stefan; Tsikos, Harilaos; Erba, Elisabetta; Price, Gregory D.; Sinninghe Damsté, Jaap S.

    2007-03-01

    A common feature of records of the early Aptian oceanic anoxic event (OAE) 1a is the sharp negative δ13C excursion displayed in both carbonate and organic matter at the onset of this event. A synchronous negative δ13C excursion has also been noted for terrestrial organic matter. This negative excursion has been attributed to either an injection of 13C-depleted light carbon into the atmosphere or, in case of marine sediments, recycling of 13C-depleted CO2. However, most studies were done on separate cores, and no information on the relative timing of the negative spikes in terrestrial versus marine records has been obtained. Here we examine early Aptian core sections from two geographically distal sites (Italy and the mid-Pacific) to elucidate the causes and relative timing of this negative "spike." At both sites, increased organic carbon (Corg) and decreased bulk carbonate contents characterize the interval recording OAE 1a (variously referred to as the "Selli event"). The organic material within the "Selli level" is immature and of autochthonous origin. Measured δ13C values of marine and terrestrial biomarkers largely covary with those of bulk organic carbon, with lowest values recorded at the base of the organic-rich section. By contrast, sediments enveloping the "Selli level" exhibit very low Corg contents, and their extractable Corg is predominantly of allochthonous origin. Hydrous pyrolysis techniques used to obtain an autochthonous, pre-Selli δ13C value for algal-derived pristane from corresponding sample material yielded a negative δ13C shift of up to 4‰. A negative δ13C shift of similar magnitude was also measured for the terrigenous n-alkanes. The results are collectively best explained by means of a massive, syndepositional, rapid input of 13C-depleted carbon into the atmosphere and surface oceans, likely delivered either via methane produced from the dissociation of sedimentary clathrates or perhaps by widespread thermal metamorphism of Corg

  10. 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.

  11. Reaction dynamics of 34-38Mg projectile with carbon target using Glauber model

    International Nuclear Information System (INIS)

    We have studied nuclear reaction cross-sections for 34-38Mg isotopes as projectile with 12C 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 37Mg is also investigated

  12. Li1.2Mn0.54Ni0.13Co0.13O2-Encapsulated Carbon Nanofiber Network Cathodes with Improved Stability and Rate Capability for Li-ion Batteries

    Science.gov (United States)

    Ma, Dingtao; Zhang, Peixin; Li, Yongliang; Ren, Xiangzhong

    2015-06-01

    Li1.2Mn0.54Ni0.13Co0.13O2-encapsulated carbon nanofiber network cathode materials were synthesized by a facile electrospinning method. The microstructures, morphologies and electrochemical properties are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), galvonostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy (EIS), etc. The nanofiber decorated Li1.2Mn0.54Ni0.13Co0.13O2 electrode demonstrated higher coulombic efficiency of 83.5%, and discharge capacity of 263.7 mAh g-1 at 1 C as well as higher stability compared to the pristine particle counterpart. The superior electrochemical performance results from the novel network structure which provides fast transport channels for electrons and lithium ions and the outer carbon acts a protection layer which prevents the inner oxides from reacting with HF in the electrolyte during charge-discharge cycling.

  13. 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

  14. 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.

  15. Poster — Thur Eve — 13: Inter-Fraction Target Movement in Image-Guided Radiation Therapy of Prostate Cancer

    International Nuclear Information System (INIS)

    We investigated the setup variations over the treatment courses of 113 patients with intact prostate treated with 78Gy/39fx. Institutional standard bladder and bowel preparation and image guidance protocols were used in CT simulation and treatment. The RapidArc treatment plans were optimized in Varian Eclipse treatment planning system and delivered on Varian 2100X Clinacs equipped with On-Board Imager to localize the target before beam-on. The setup variations were calculated in terms of mean and standard deviation of couch shifts. No correlation was observed between the mean shift and standard deviation over the treatment course and patient age, initial prostate volume and rectum size. The mean shifts in the first and last 5 fractions are highly correlated (P < 10−10) while the correlation of the standard deviations cannot be determined. The Mann-Kendall tests indicate trends of the mean daily Ant-Post and Sup-Inf shifts of the group. The target is inferior by ∼1mm to the planned position when the treatment starts and moves superiorly, approaching the planned position at 10th fraction, and then gradually moves back inferiorly by ∼1mm in the remain fractions. In the Ant-Post direction, the prostate gradually moves posteriorly during the treatment course from a mean shift of ∼2.5mm in the first fraction to ∼1mm in the last fraction. It may be related to a systematic rectum size change in the progress of treatment. The biased mean shifts in Ant-Post and Sup-Inf direction of most patients suggest systematically larger rectum and smaller bladder during the treatment than at CT simulation

  16. Revisiting the Laser Dye Styryl-13 As a Reference Near-Infrared Fluorophore: Implications for the Photoluminescence Quantum Yields of Semiconducting Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Stürzl, Ninette; Lebedkin, Sergei; Kappes, Manfred M.

    2009-08-01

    The near-infrared (NIR) polymethine dye Styryl-13 emitting at ˜925 nm has recently been suggested as a reference fluorophore for determining the quantum yield (QY) of the NIR photoluminescence of dispersed single-walled carbon nanotubes (SWNTs). Ju et al. reported the QY for SWNTs to be as high as 20% on the basis of 11% QY for Styryl-13 in methanol (Science 2009, 323, 1319). We directly compared the fluorescence of Styryl-13 and Styryl-20 (emitting at ˜945 nm) with that of the standard fluorophore Rhodamine 6G using a spectrometer with a broad visible-NIR detection range. QYs of 2.0 (4.5) and 0.52 (0.80)% were determined for Styryl-13 and Styryl-20 in methanol (propylene carbonate), respectively. Correspondingly, the above-mentioned photoluminescence efficiency of SWNTs appears to be strongly overestimated. We also discuss singlet oxygen as an alternative NIR reference. A total QY of 1.4% was measured for the emission of singlet oxygen at 1275 nm, as photosensitized by C70 fullerene in air-saturated carbon tetrachloride.

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

    International Nuclear Information System (INIS)

    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+ but not Her2- 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+ 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.

  18. Ribbon target assembly using carbon graphite for secondary emission type beam profile monitor

    International Nuclear Information System (INIS)

    We developed a secondary emission type beam profile monitor with graphite ribbons as a beam target. The graphite is excellent in endurance against heat load, and that they are thin as 1.6-2.0 micron and low z (=6) is advantage for reducing beam loss. Furthermore, since ribbons emits larger amount of electrons than ordinal metal wires because of larger surface, the monitor has higher sensitivity. On the other hands, in case of multi-ribbon type, uniformity of secondary electron emission is required for accurate measurement. For the uniform emission, not only surface homogeneity, but also evenness for each ribbon width is needed. A suitable manufacturing method to make ribbon target from graphite-foil, and emission uniformity has been studied. (author)

  19. X-ray film chamber with carbon target of Tien-Shan complex array

    International Nuclear Information System (INIS)

    X-ray films were exposed inside the ionization calorimeter under 74g/sq cm of carbon and 5 cm of lead. The X-ray film chamber area is 35 sq. m. Moving X-ray films were used, 50% of the events, which yield incidence time, were identified with corresponding extensive air showers (EAS). For such events the size spectrum of associated EAS was derived. Two methods of energy measurement using X-ray films and ionization calorimeter were compared. The energy transfer from selected hadrons to electromagnetic components is illustrated. It is found that in cascades with high energy release into electromagnetic components the hadron component is practically absent

  20. L-shell ionization in high-z targets by carbon and silicon ions

    International Nuclear Information System (INIS)

    L-shell ionization in Ho, Er, Tm, Ta, W, Tl, Pb and Bi by 20 Mev carbon ions and 37.5 Mev silicon ions has been investigated. The observed L/sub //alpha/sub L//gamma/ x-ray intensity ratios are compared with the estimates based on PWBA and BEA calculations. The energy shifts in the L/sub //alpha/, L/sub //gamma/sub //1 and L/sub //gamma/sub //4 x-rays are attributed to the presence of M shell spectator vacancies. 7 refs

  1. 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.

  2. Carbon dioxide mitigation target of China in 2020 and key economic sectors

    International Nuclear Information System (INIS)

    China proposed a CO2 mitigation target in 2020 to deal with anthropogenic global climate change. Chinese policy makers mainly focus on three factors comprising consumption structure changes, energy technology development, and new energy increments. In addition, sectoral CO2 reduction is increasingly concerned in the world. Thus, it is significant to investigate integrated impacts of three factors to China's CO2 mitigation target as well as to identify key economic sectors for achieving this target. In this study, energy demand and CO2 emission in 2020 are predicted. Five scenarios are generated to illustrate the contributions of three factors. In addition, twelve key economic sectors for reducing energy demand and CO2 emission are identified from both production and final demand perspectives. Under integrated impacts of three factors, China's CO2 intensity per unit gross domestic product in 2020 will decrease by about 43.9% in 2020 than 2005 level. In the short term, China's CO2 mitigation will be highly dependent on energy technology development. In the long term, it will mainly rely on reshaped consumption structure changes and new energy development. In addition, China's future policies should focus on 12 identified key economic sectors. - Highlights: ► China's energy demand and CO2 emission in 2020 are predicted. ► Integrated impacts of three factors can achieve CO2 mitigation target in 2020. ► Twelve key sectors for China's CO2 mitigation are identified on a life cycle basis. ► In the short term, China's CO2 mitigation highly depends on technology development. ► In the long term, it relies on reshaped structure changes and new energy sources

  3. 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.

  4. 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

  5. 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)

  6. 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...

  7. 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)

  8. 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.

  9. 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

  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

    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.

  12. 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.

  13. 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)

  14. 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

  15. 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.)

  16. 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

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

    International Nuclear Information System (INIS)

    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. Cmax and AUC0–24h 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 (pasireotide

  18. 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.

  19. Fabrication of poly(γ-glutamic acid)-based biopolymer as the targeted drug delivery system with enhanced cytotoxicity to APN/CD13 over-expressed cells.

    Science.gov (United States)

    Zhang, Li; Geng, Xu; Zhou, Jie; Wang, Ying; Gao, Hongliang; Zhou, Yue; Huang, Jing

    2015-06-01

    Poly(γ-glutamic acid)-based targeted drug delivery system (PAMCN) targeting transmembrane metalloprotease aminopeptidase-N (APN/CD13) was fabricated and evaluated for the enhancement of targeting efficiency and cytotoxicity. The cisplatin (CDDP) loading content of PAMCN was about 36 ± 5% and PAMCN showed a sustainable release profile with a half-maximal release time (t1/2) of 23 h. The average size of PAMCN was 132 ± 18 nm determined by light scattering (LS) and 158 ± 67 nm by atomic force microscopy (AFM). Flow cytometry and fluorescence microscope analysis showed that the drug carrier (PAMN) could specifically bind to human umbilical vein endothelial cells (HUVEC). PAMCN enhanced the efficacy of CDDP to HUVEC cells with the half maximal inhibitory concentration (IC50) value decreased to 90.83 ± 33.00 μg/ml comparing with free CDDP treatment and showed less tube formation amounts (p < 0.01) than free CDDP in matrigel angiogenesis inhibition assay in vitro. In vivo toxicity experiment indicated that the survival rate of KM mice in PAMCN group was 100% and PAMCN reduced the hepatic and renal toxicity significantly compared to free CDDP group. Therefore, this novel drug delivery system presents a promising potential for antiangiogenic chemotherapy. PMID:25648136

  20. 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

  1. 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

  2. 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)

  3. 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.

  4. 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

  5. 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

  6. A modern literature review of carbon monoxide poisoning theories, therapies, and potential targets for therapy advancement.

    Science.gov (United States)

    Roderique, Joseph D; Josef, Christopher S; Feldman, Michael J; Spiess, Bruce D

    2015-08-01

    The first descriptions of carbon monoxide (CO) and its toxic nature appeared in the literature over 100 years ago in separate publications by Drs. Douglas and Haldane. Both men ascribed the deleterious effects of this newly discovered gas to its strong interaction with hemoglobin. Since then the adverse sequelae of CO poisoning has been almost universally attributed to hypoxic injury secondary to CO occupation of oxygen binding sites on hemoglobin. Despite a mounting body of literature suggesting other mechanisms of injury, this pathophysiology and its associated oxygen centric therapies persists. This review attempts to elucidate the remarkably complex nature of CO as a gasotransmitter. While CO's affinity for hemoglobin remains undisputed, new research suggests that its role in nitric oxide release, reactive oxygen species formation, and its direct action on ion channels is much more significant. In the course of understanding the multifaceted character of this simple molecule it becomes apparent that current oxygen based therapies meant to displace CO from hemoglobin may be insufficient and possibly harmful. Approaching CO as a complex gasotransmitter will help guide understanding of the complex and poorly understood sequelae and illuminate potentials for new treatment modalities. PMID:25997893

  7. 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

  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. 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

  10. 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

  11. Correlation between the carbon isotope composition (δ13 C) of puccinellia ciliata and balansa clover in duel stresses of water logging and salinity (Nacl)

    International Nuclear Information System (INIS)

    Theoretically, plants growing under stress conditions, such as in saline or waterlogged conditions, should behave with 13C02 discrimination and have different δ13C values. Therefore, this experiment was conducted to evaluate the effect of factors such as salinity and hypoxia in affecting delta values of Puccinellia ciliata and Balansa clover (Trifolium michelianum Savi. Var balansae boiss). This study reveals that these two species (C3 plants) behave differently and B. clover has more positive δ13C values (7.6%) compared to P. ciliata. The overall average of δI3C were -28.85 and -26.66 0/00, respectively, for P. ciliata and B. clover. The δI3C values for the shoots and roots of the two species also have different values (more positive values in roots compared to shoots). Water logging and salinity have a significant affect on 13C02 discrimination and, statistically, these effects on δ13C values are significant (ρ I3C would be changed (less discrimination for hypoxia and more for salinity conditions). The combined effects on species and plant parts of water logging and salinity are not statistically insignificant on δ13C values, however, each factor separately has a significant effect on δ13C values. P. ciliata was grown in different seasons (summer and winter) and showed significant differences in δ13C values (by almost 4%). The carbon content (%) of the two species was different, but, were not related to δ13C, respectively

  12. 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.

  13. 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)

  14. 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

  15. Carbon isotopic composition, nitrogen content and inclusion composition of diamonds from the Roberts Victor kimberlite, South Africa: Evidence for 13C depletion in the mantle

    International Nuclear Information System (INIS)

    The mean 13C-content of diamonds containing peridotitic minerals does not differ significantly from those containing sulfides. Diamonds containing eclogitic minerals can be subdivided into two groups based on their carbon isotopic composition: Group-A, and Group-B. The clinopyroxenes occluded by the Group-A diamonds are depleted in SiO2, MgO, and CaO and significantly enriched in Al2O3, FeO, and MnO compared to clinopyroxenes occluded by Group-B diamonds. Carbon in two graphite-diamond eclogites has a mean isotopic composition of -5.31%; in both samples graphite shows a slight enrichment in 13C compared to the coexisting diamond. There is no difference in the C isotopic composition between Type I and Type II diamonds for sulfide and peridotitic minerals occluding diamonds. All Type II diamonds containing eclogitic minerals belong to Group-A. No correlation between N content and C isotopic composition could be established, although a large range in both variables is observed for the sample suite. The composition of eclogitic minerals included in diamonds of low 13C-content differs from that of eclogite xenoliths characterized by 18O-depletions, which have been related to subduction processes. Hence the data available do not suggest a common cause for the depletion of the heavy isotopes of the two elements. The chemical and isotopic characteristics of the suite of diamond samples reflect different mantle environments. Diamonds depleted in 13C(13C = -15 to -16 per mille) come from a region at greater depth than those of 13C contents of -5 to -6 per mille. The source region of the former is characterized by higher Fe, Mn, Al, and lower Mg, Ca, Si, and N contents than that of the latter. (author)

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Effects of air pollutants on the composition of stable carbon isotopes δ13C, of leaves and wood, and on leaf injury

    International Nuclear Information System (INIS)

    Air pollutants are known to cause visible leaf injury as well as impairment of photosynthetic CO2 fixation. Here we evaluate whether the effects on photosynthesis are large enough to cause changes in the relative composition of stable carbon isotopes, δ13C, of plant tissue samples, and, if so, how the changes relate to visual leaf injury. For that purpose, several woody and herbaceous plant species were exposed to SO2 + O3 and SO2 + O3 + NO2 for one month. At the end of the fumigations, the plants were evaluated for visual leaf lesions, and δ13C of leaf tissue was determined. Woody plants generally showed less visual leaf injury and smaller effects on δ13C of pollutant exposure than did herbaceous plants. If δ13C was affected by pollutants, it became, with few exceptions, less negative. The data from the fumigation experiments were consistent with δ13C analyses of whole wood of annual growth rings from two conifer tree species, Pseudotsuga menziesii and Pinus strobus. These trees had been exposed until 1977 to exhaust gases from a gas plant at Lacq, France. Wood of both conifer species formed in the polluted air of 1972 to 1976 had less negative δ13C values than had wood formed in the much cleaner air in 1982 to 1986. No similar, time-dependent differences in δ13C of wood were observed in trees which had been continuously growing in clean air. Our δ13C data from both relatively short-term artificial exposures and long-term natural exposure are consistent with greater stomatal limitation of photosynthesis in polluted air than in clean air

  1. 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

  2. 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)

  3. 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

  4. Nature of organic carbon and nitrogen in physically protected organic matter of some Australian soils as revealed by solid-state 13 C and 15 N NMR spectroscopy

    International Nuclear Information System (INIS)

    The 13C and 15N nuclear magnetic resonance (NMR) spectroscopy was applied for characterising the chemical nature of the remaining organic fraction. The 13C NMR spectroscopic comparison of the residues after UV photo-oxidation and the untreated bulk soils revealed a considerable increase in condensed aromatic structures in the residues for 4 of the 5 soils. This behaviour was recently shown to be typical for char-containing soils. In the sample where no char was detectable by NMR spectroscopy, the physically protected carbon consisted of functional groups similar to those observed for the organic matter of the bulk sample, although their relative proportions were altered. The solid-state 15N NMR spectrum from this sample revealed that some peptide structures were able to resist UV photo-oxidation, probably physically protected within the core of micro aggregates. Heterocyclic aromatic nitrogen was not detected in this spectrum, but pyrrolic nitrogen was found to comprise a major fraction of the residues after photo-oxidation of the <53 μm containing soils. Acid hydrolysis of these samples confirmed that some peptide-like material was still present. The identification of a considerable amount of aromatic carbon and nitrogen, assignable to charred material in 4 of the 5 investigated soils, supports previous observations that char largely comprises the inert or passive organic matter pool of many Australian soils. The influence of such material on the carbon and nitrogen dynamics in such soils, however, requires further research. Copyright (2000) CSIRO Australia

  5. Paramagnetic ion binding to amino acids: The structure of the manganese (II)-L-proline complex from carbon-13 relaxation data

    International Nuclear Information System (INIS)

    Carbon-13 longitudinal relaxation times T1 of aqueous solutions of proline at pH = 11 containing 10-4-10-5M manganese(II) perchlorate are measured at 62.86 MHz und 600C. Under these conditions, the Mn2+ cation is bound to three proline molecules in their dibasic form to form the complex [Mn(L-PRO-)3]-. The relaxation of carbons α, β, γ, delta in this complex is shown to be dipolar. The relevant correlation time is rotational tausub(r) = 4.3 x 1011s (at 600C). A method is given to compute the Mn2+-13C distances in the complex from the paramagnetic relaxation rates 1/T1sub(M) of carbons α to delta and an assumed geometry of the proline molecule. The manganes (II) cation may be positioned with respect to each proline ligand, thus determining the structure of the hexacoordinated complex. The sites of coordination are the uncharged nitrogen and one carboxylic oxygen atom of the proline molecules, their distance to the Mn2+ cation are respectively 2.22 and 1.97 A. (orig.)

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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

  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. 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 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 saguaro 30 km distant. Temporal isotopic records from saguaro and potentially other long-lived succulent plants may provide useful high-frequency records of ecological responses to climate variation in desert environments where other such records are lacking.

  16. Determination of organic carbon (%) y δ13 C(0/00) in a Typic Paleudult (Ultisol) of the Araucania Region

    International Nuclear Information System (INIS)

    The use of isotopic techniques had resulted in a great utility for the quantification of the quantity and the origin of the organic C and N that are accumulated in the soil annually. In the same way, its possible to establish the single and complex substrates decomposition rates under natural and controlled conditions, for longer periods after the initial substrate are being metabolized. The relation 13C/12C is measure as δ13C. The C4 species as maize have a δ13C value of -120/00 approximately, whilst the C3 species as wheat and rice have a -260/00 value, approximately. The MOS δ13C relates with the crop type and with the plant C3 to C4 changes, reflecting on a change of the MOS δ13C values. This principle have been used by Balesdent, Mariotti and Guillet, and Accode et al. To investigate and quantification the soil organic matter changes. The objective of this study was to quantify the Oc and delta 13C in a soil Serie Metrenco, Family fine, mesica mixed of the Typic Paleudult (Ultisol) of the IX Region. The δ13C analysis were done in a mass spectrometer (OPTIMA) at the Seibersdorf Laboratories, Vienna, Austria. The OC and particle size fractionation analysis were done at the Agriculture Section of the CCHEN. The research studied the OC amount and the δ13C datas obtained on soil samples in three profiles (up, middle, down) in a slope direction, under a 50 year burn residues traditional management system, to verify the C4 plants presence or absence in the crop rotation. The results showed a big decreased of the δ13C in the profile, meaning that an increase of the 12C in depth, specially in the <50μm fraction has the highest proportion of soil OC. These results indicate the absence of C4 plants in the crop rotation and a high OC percentage in the recalcitrant fraction (AN)

  17. 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...

  18. 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

  19. 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.

  20. Dual isotope (13C-14C) Studies of Water-Soluble Organic Carbon (WSOC) Aerosols in South and East Asia

    OpenAIRE

    Kirillova, Elena N.

    2013-01-01

    Atmospheric aerosols may be emitted directly as particles (primary) or formed from gaseous precursors (secondary) from different natural and anthropogenic sources. The highly populated South and East Asia regions are currently in a phase of rapid economic growth to which high emissions of carbonaceous aerosols are coupled. This leads to generally poor air quality and a substantial impact of anthropogenic aerosols on the regional climate. However, the emissions of different carbon aerosol comp...

  1. INTERVALOS DE INTEGRACIÓN UNIFICADOS PARA LA CARACTERIZACIÓN ESTRUCTURAL DE PETRÓLEOS, CARBONES O SUS FRACCIONES POR RMN 1H Y RMN 13C

    Directory of Open Access Journals (Sweden)

    Avella Eliseo

    2010-09-01

    Full Text Available Con base en la revisión de publicaciones, hechas entre 1972 y 2006, se evidenció que hay imprecisiones en los límites de los intervalos de integración que los autores asignan a las señales en resonancia magnética nuclear (RMN para hacer la caracterización estructural de petróleos, carbones o sus fracciones derivadas, a partir de sus espectros de hidrógeno (RMN 1H o de carbono (RMN 13C. En consecuencia, se determinaron límites unificados para la integración de los espectros RMN 1H y RMN 13C de tales muestras mediante un tratamiento estadístico aplicado a los límites de los intervalos de integración ya publicados. Con esos límites unificados se elaboraron cartas de correlación en RMN útiles para la asignación de la integral en esos intervalos, y aun en otros de menor extensión definidos en función de la intersección entre asignaciones diferentes. Además se plantearon ecuaciones necesarias para establecer la integral atribuible a fragmentos más específicos en un intento por hacer una caracterización estructural más exacta a partir de los espectros RMN de petróleos, carbones o sus fracciones derivadas.

  2. The effect of cesium carbonate on 1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 aggregation in films

    International Nuclear Information System (INIS)

    Surface-pressure versus molecular area isotherms, X-ray reflectivity, and X-ray near-total reflection fluorescence were used to study the properties of 1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (PCBM) that was pre-mixed with cesium carbonate and spread as a film at the air-water interface. The pre-mixed PCBM with cesium carbonate demonstrated a strikingly strong effect on the organization of the film. Whereas films formed from pure PCBM solution were rough due to strong inter-molecular interactions, the films formed from the mixture were much smoother. This indicates that the cesium carbonate moderates the inter-molecular interactions among PCBM molecules, hinting that the cesium diffusion observed in inverted organic photovoltaic structures and the likely ensuing ionic Cs-PCBM interaction decrease aggregation tendency of PCBM. This implies that the use of cesium salts affects the morphology of the organic layer and consequently improves the efficiency of these devices

  3. 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

  4. Production of oxygen-15, nitrogen-13 and carbon-11 and of their low molecular weight derivatives for biomedical applications

    International Nuclear Information System (INIS)

    The production and the medical use of the short-lived radioisotopes of the 3 major elements of the biosphere, 13N, 11C and 15O, require the vicinity of a cyclotron, of radiochemistry laboratories and of a suitably equipped medical unit. The methodological and practical aspects of the routine, high efficiency, production of these gases, with the specifications that result from their medical use, are discussed and described. (author)

  5. Phosphorus-31 and carbon-13 nuclear magnetic resonance studies of glucose and xylose metabolism in Candida tropicalis cell suspensions.

    OpenAIRE

    Lohmeier-Vogel, E M; Hahn-Hägerdal, B.; Vogel, H J

    1995-01-01

    The metabolism of glucose and xylose was studied as a function of oxygenation in suspensions of Candida tropicalis by 31P and 13C nuclear magnetic resonance spectroscopy. Both the rate of carbohydrate metabolism and the cytoplasmic pH were independent of the rate of oxygenation in cells metabolizing glucose. However, these two parameters were markedly dependent on the rate of oxygenation in C. tropicalis cells metabolizing xylose. For example, the cytoplasmic pH in fully oxygenated xylose-met...

  6. 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.

  7. 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

  8. 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)

  9. Complete assignment of the methionyl carbonyl carbon resonance in switch variant anti-dansyl antibodies labeled with (1- sup 13 C)methionine

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Koichi; Matsunaga, C.; Igarashi, Takako; Kim, Hahyung; Odaka, Asano; Shimada, Ichio; Arata, Yoji (Univ. of Tokyo, Hongo (Japan))

    1991-01-01

    A {sup 13}C NMR study is reported of switch variant anti-dansyl antibodies developed by Dangl et al. who had used the fluorescence-activated cell sorter to select and clone these variants. These switch variant antibodies possess the identical V{sub H}, V{sub L}, and C{sub L} domains in conjunction with different heavy chain constant regions. In the present study, switch variant antibodies of IgG1, IgG2a, and IgG2b subclasses were used along with a short-chain IgG2a antibody, in which the entire C{sub H}1 domain is deleted. The switch variant antibodies were specifically labeled with (1-{sup 13}C)methionine by growing hybridoma cells in serum-free medium. Assignments of all the methionyl carbonyl carbon resonances have been completed by using the intact antibodies along with their fragments and recombined proteins in which either heavy or light chain is labeled. A double labeling method has played a crucial role in the process of the spectral assignments. The strategy used for the assignments has been described in detail. In incorporating {sup 15}N-labeled amino acids into the antibodies for the double labeling, isotope dilution caused a serious problem except in the cases of ({alpha}-{sup 15}N)lysine and ({sup 15}N)threonine, both of which cannot become the substrate of transaminases. It was found that {beta}-chloro-L-alanine is most effective in suppressing the isotope scrambling. So far, spectral assignments by the double labeling method have been possible with {sup 15}N-labeled Ala, His, Ile, Lys, Met, Ser, Thr, Tyr, and Val. On the basis of the results of the present {sup 13}C study, possible use of the assigned carbonyl carbon resonances for the elucidation of the structure-function relationship in the antibody system has been briefly discussed.

  10. Designing a HER2/neu promoter to drive α1,3galactosyltransferase expression for targeted anti-αGal antibody-mediated tumor cell killing

    International Nuclear Information System (INIS)

    Our goal was to specifically render tumor cells susceptible to natural cytolytic anti-αGal antibodies by using a murine α1,3galactosyltransferase (mαGalT) transgene driven by a designed form of HER2/neu promoter (pNeu), the transcription of which is frequently observed to be above basal in breast tumors. Indeed, the αGalT activity that promotes Galα1,3Galβ1,4GlcNAc-R (αGal) epitope expression has been mutationally disrupted during the course of evolution, starting from Old World primates, and this has led to the counter-production of large amounts of cytotoxic anti-αGal antibodies in recent primates, including man. Expression of the endogenous c-erbB-2 gene was investigated in various cell lines by northern blotting. A mαGalT cDNA was constructed into pcDNA3 vector downstream of the original CMV promoter (pCMV/mαGalT) and various forms of pNeu were prepared by PCR amplification and inserted in the pCMV/mαGalT construct upstream of the mαGalT cDNA, in the place of the CMV promoter. These constructs were transferred into HEK-293 control and breast tumor cell lines. Stably transfected cells were analyzed by northern blotting for their expression of αGalT and c-erbB-2, and by flow cytometry for their binding with fluorescein isothiocyanate-conjugated Griffonia simplicifolia/isolectin B4. We show that expression of the mαGalT was up- or down-modulated according to the level of endogenous pNeu activity and the particular form of constructed pNeu. Among several constructs, two particular forms of the promoter, pNeu250 containing the CCAAT box and the PEA3 motif adjacent to the TATAA box, and pNeu664, which has three additional PEA3 motifs upstream of the CCAAT box, were found to promote differential αGalT expression. Our results strengthen current concepts about the crucial role played by the proximal PEA3 motif of pNeu, and may represent a novel therapeutic approach for the development of targeted transgene expression

  11. 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

  12. 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)

  13. Carbonation of C–S–H and C–A–S–H samples studied by 13C, 27Al and 29Si MAS NMR spectroscopy

    International Nuclear Information System (INIS)

    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 CO2 at room temperature and high relative humidity and studied after one to 12 weeks. 29Si 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 Q3 and Q4 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 13C NMR. For C–A–S–H samples with Ca/Si = 1.0 and 1.5, 27Al 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)4 units in the amorphous silica phase. A small amount of penta-coordinated Al sites has also been identified in the silica phase

  14. 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.

  15. 13C and 17O NMR binding constant studies of uranyl carbonate complexes in near-neutral aqueous solution. Yucca Mountain Project Milestone Report 3351

    International Nuclear Information System (INIS)

    Valuable structural information, much of it unavailable by other methods, can be obtained about complexes in solution through NMR spectroscopy. From chemical shift and intensity measurements of complexed species, NMR can serve as a species-specific structural probe for molecules in solution and can be used to validate thermodynamic constants used in geochemical modeling. Fourier-transform nuclear magnetic resonance (FT-NMR) spectroscopy has been employed to study the speciation of uranium(VI) ions in aqueous carbonate solutions as a function of pH, ionic strength, carbonate concentration, uranium concentration, and temperature. Carbon-13 and oxygen-17 NMR spectroscopy were used to monitor the fractions, and hence thermodynamic binding constants of two different uranyl species U02(CO3)34- and (UO2)3(CO3)66- in aqueous solution. Synthetic buffer solutions were prepared under the ionic strength conditions used in the NMR studies in order to obtain an accurate measure of the hydrogen ion concentration, and a discussion of pH = -log(aH+) versus p[H] = -log[H+] is provided. It is shown that for quantitative studies, the quantity p[H] needs to be used. Fourteen uranium(VI) binding constants recommended by the OECD NEA literature review were corrected to the ionic strengths employed in the NMR study using specific ion interaction theory (SIT), and the predicted species distributions were compared with the actual species observed by multinuclear NMR. Agreement between observed and predicted stability fields is excellent. This establishes the utility of multinuclear NMR as a species-specific tool for the study of the actinide carbonate complexation constants, and serves as a means for validating the recommendations provided by the OECD NEA

  16. A nitrogen fertilization field study of carbon-13 and nitrogen-15 transfers in ectomycorrhizas of Pinus sabiniana.

    Science.gov (United States)

    Albarracín, María Victoria; Six, Johan; Houlton, Benjamin Z; Bledsoe, Caroline S

    2013-12-01

    Ectomycorrhizal (EM) fungi form relationships with higher plants; plants transfer C to fungi, and fungi transfer nutrients to their host. While evidence indicates that this interaction is largely mutualistic, less is known about how nutrient supply and EM associates may alter C and nutrient exchanges, especially in intact plant-soil-microbe systems in the field. In a dual-labeling experiment with N fertilization, we used C and N stable isotopes to examine in situ transfers in EM pine trees in a Pinus sabiniana woodland in northern California. We added (15)NH4SO2 and (13)CO2 to track (13)C transfer from pine needles to EM roots and (15)N transfer from soil to EM roots and pine needles. Transfers of (13)C and (15)N differed with EM morphotype and with N fertilization. The brown morphotype received the least C per unit of N transferred (5:1); in contrast red and gold morphotypes gained more C and transferred less N (17:1 and 25:1, respectively). N fertilization increased N retention by ectomycorrhizas (EMs) but did not increase N transfer from EMs to pine needles. Therefore N fertilization positively affected both nutrient and C gains by EMs, increasing net C flows and N retention in EMs. Our work on intact and native trees/EM associations thereby extends earlier conclusions based on pot studies with young plants and culturable EM fungi; our results support the concept that EM-host relationships depend on species-level differences as well as responses to soil resources such as N. PMID:23912260

  17. Elucidation of intermediate (mobile) and slow (solidlike) protein motions in bovine lens homogenates by carbon-13 NMR spectroscopy

    International Nuclear Information System (INIS)

    The motional dynamics of lens cytoplasmic proteins present in calf lens homogenates were investigated by two 13C nuclear magnetic resonance (NMR) techniques sensitive to molecular motion to further define the organizational differences between the cortex and nucleus. For the study of intermediate (mobile) protein rotational reorientation motion time scales [rotational correlation time (τ0) range of 1-500 ns], the authors employed 13C off-resonance rotating frame spin-lattice relaxation, whereas for the study of slow (solidlike) motions (τ0 ≥ 10 μs) they used the solid-state NMR techniques of dipolar decoupling and cross-polarization. The frequency dependence of the peptide bond carbonyl off-resonance rotating frame spectral intensity ratio of the lens proteins present in native calf nuclear homogenate at 35 degree C indicates the presence of a polydisperse mobile protein fraction with a τ0,eff (mean) value of 57 ns. Lowering the temperature to 1 degree C, a temperature which produces the cold cataract, results in an overall decrease in τ0,eff to 43 ns, suggesting a selective removal of βH-, LM-, and possibly γs-crystallins from the mobile lens protein population. The presence of solidlike or motionally restricted protein species was established by dipolar decoupling and cross-polarization. Comparison of proton dipolar-decoupled and nondecoupled 13C NMR spectra of native cortical homogenate at 20 degree C indicates the absence of significant contributions from slowly tumbling, motionally restricted species. These studies establish the presence of both mobile and solidlike protein phases in calf lens nuclear homogenate, whereas for the native cortical homogenate, within the detection limits of NMR, the protein phase is mobile, except at low temperature where a small fraction of solidlike protein phase is present

  18. 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)

  19. Non-destructive analysis of the oil composition of soybean seeds by natural abundance carbon-13 nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    The signals of fatty acids in the form of triglycerides were observed in the 13C NMR spectrum of an intact soybean seed. The major fatty acid component composition of triglycerides in a soybean seed, which includes linoleic acid, oleic acid and palmitic acid, was estimated by subtracting the spectra of authentic fatty acids from the spectrum of the intact soybean seeds. The fatty acid compositions of seeds of 11 Japanese soybean cultivars and 5 lines bred at the Asian Vegetable Research and Development Center (AVRDC) were estimated by this rapid (within 1hr for one seed) and nondestructive analytical method. (author)

  20. Priming of Soil Carbon Decomposition in Two Inner Mongolia Grassland Soils following Sheep Dung Addition: A Study Using 13C Natural Abundance Approach

    Science.gov (United States)

    Ma, Xiuzhi; Ambus, Per; Wang, Shiping; Wang, Yanfen; Wang, Chengjie

    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) and a heavily degraded Artemisia frigida dominated community (1.3% organic matter content). Dung was collected from sheep either fed on L. chinensis (C3 plant with δ13C = −26.8‰; dung δ13C = −26.2‰) or Cleistogenes squarrosa (C4 plant with δ13C = −14.6‰; dung δ13C = −15.7‰). Fresh C3 and C4 sheep dung was mixed 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 δ13C 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 CO2. The cumulative amounts of C respired from dung treated soils during 152 days were 7–8 times higher than in the un-amended controls. In both grassland soils, ca. 60% of the evolved CO2 originated from the decomposing sheep dung and 40% from the native soil C. Priming effects of soil C decomposition were observed in both soils, i.e. 1.4 g and 1.6 g additional soil C kg−1 dry soil had been emitted as CO2 for the L. chinensis and A. frigida soils, respectively. Hence, the net C losses from L. chinensis and A. frigida soils were 0.6 g and 0.9 g C kg−1 soil, which was 2.6% and 7.0% of the total C in L. chinensis and A. frigida grasslands soils, respectively. Our results suggest that grazing of degraded Inner Mongolian pastures may cause a net soil C loss due to the positive priming effect, thereby accelerating soil deterioration. PMID:24236024

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. Organic Carbon Delivery to a High Arctic Watershed over the Late Holocene: Insights from Plant Biomarkers and Compound Specific δ13C and Δ14C Measurements

    Science.gov (United States)

    Schreiner, K. M.; Bianchi, T. S.; Eglinton, T. I.; Allison, M. A.

    2012-12-01

    The Colville River in Alaska is the largest river in North America which has a drainage basin that is exclusively underlain by permafrost, and as such provides a unique signal of historical changes in one of the world's most vulnerable areas to climate changes. Additionally, the Colville flows into Simpson's Lagoon, an area of the Alaskan Beaufort coast protected by a barrier island chain, lessening the impacts of Arctic storms and ice grounding on sediment mixing. Cores collected from the Colville river delta in August of 2010 were found to be composed of muddy, organic-rich, well-laminated sediments. The 2.5 to 3 meter length of each core spans about one to two thousand years of Holocene history, including the entire Anthropocene and much of the late Holocene. Two cores were sampled for this data set - one from close to the river mouth, and one from farther east in Simpson's Lagoon. Samples were taken every 2 cm for the entire length of both cores. In order to determine how the amount of terrestrial organic matter input changed over the Holocene, bulk analyses including percent organic carbon, percent nitrogen, and stable carbon isotopic analysis were performed, and biomarkers including lignin-phenols and fatty acids were measured. It was shown that lignin-phenol input is positively correlated with Alaskan North Slope temperature reconstructions. To determine whether the source of this increased terrestrial organic matter input was from fresh vegetation (for example, shrub encroachment onto tundra areas) or aged soil organic matter (potentially due to permafrost thawing and breakdown), selected samples were analyzed for compound-specific δ13C and Δ14C of fatty acids and lignin-phenols. These analyses show significant changes in carbon storage and in terrestrial carbon delivery to the Lagoon over time. These results represent the first fine-scale organic biomarker study in a high Arctic North American Lagoon, and have many implications for the future of carbon

  6. 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

  7. 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

  8. Aircraft observation of carbon dioxide at 8-13 km altitude over the western Pacific from 1993 to 1999

    Energy Technology Data Exchange (ETDEWEB)

    Matsueda, H.; Inoue, H.Y.; Ishii, M. [Meteorological Research Inst., Ibaraki-ken (Japan). Geochemical Research Dept.

    2002-01-01

    The spatial and temporal variations of atmospheric CO{sub 2} at 8-13 km from April 1993 to April 1999 were observed by measuring CO{sub 2} mixing ratios in samples collected biweekly from a commercial airliner between Australia and Japan. The CO{sub 2} growth rate showed a considerable inter annual variation, with a maximum of about 3 ppm/yr during late 1997. This variation is related to the EI Nino/Southern Oscillation (ENSO) events. A year-to-year change related to the ENSO events was also found in the latitudinal distribution pattern of the CO{sub 2} annual mean between 30 deg N and 30 deg S. The averaged CO{sub 2} seasonal cycle in the Northern Hemisphere gradually decayed toward the equator, and a relatively complicated variation with a double seasonal maximum appeared in the Southern Hemisphere. A significant yearly change of the seasonal cycle pattern was observed in the Southern Hemisphere. The impact of a tropical biomass-burning injection on the upper tropospheric CO{sub 2} was estimated on the basis of the CO data from the same airliner observation.

  9. Kinetics of absorption of carbon dioxide into aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol

    Energy Technology Data Exchange (ETDEWEB)

    Francis Bougie; Maria C. Iliuta [Laval University, Quebec, PQ (Canada). Chemical Engineering Department

    2009-01-15

    In this work the kinetics of the reaction between CO{sub 2} and a sterically hindered alkanolamine, 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) were determined at temperatures of 303.15, 313.15 and 323.15 K in a wetted wall column contactor. The AHPD concentration in the aqueous solutions was varied in the range 0.5-2.4 kmol m{sup -3}. The ratio of the diffusivity and Henry's law constant for CO{sub 2} in solutions was estimated by applying the N{sub 2}O analogy and the Higbie penetration theory, using the physical absorption data of CO{sub 2} and N{sub 2}O in water and of N{sub 2}O in amine solutions. Based on the pseudo-first-order for the absorption of CO{sub 2}, the overall pseudo-first-order rate constants were determined from the kinetics measurements. By considering the zwitterion mechanism for the reaction of CO{sub 2} with AHPD, the zwitterion deprotonation and second-order rate constants were calculated. The second-order rate constant, k{sub 2}, was found to be 285, 524, and 1067 m{sup 3} kmol{sup -1} s{sup -1} at 303.15, 313.15, and 323.15 K, respectively.

  10. Relationship between Yield, Carbon Isotope Discrimination (Δ13C) and Water Use Efficiency of Durum Wheat in the Syrian Arab Republic. 3. Simulation Modelling

    International Nuclear Information System (INIS)

    Six durum wheat genotypes were grown at Tel Hadya during the three seasons 2004-2005, 2005-2006 and 2006-2007, and the data were used to calibrate and validate the simulation model SIMWASER. Simulated and measured soil water status and yield production showed very good conformity, and therefore SIMWASER was able to reproduce the water balance of the site in a realistic manner, as well as yield production throughout the season. The validated model was run for the period between 1980 and 2007 for the Tel Hadya site using daily weather data. Also, different genetic scenarios were used regarding different transpiration values. Carbon isotope discrimination (Δ13C) was used as a closely-related surrogate for transpiration at the plant level. The simulated yields showed weak relationships with measured rainfall. However, closer relationships (higher R2) were found between simulated yield and plant transpiration. Moreover, when years were grouped according to rainfall, dry years (rainfall 175 mm), stronger relationships were evident between simulated yield and measured rainfall. The dry years produced much higher yields per unit of rainfall (rainfall use efficiency) compared with the wetter years, ranging between 13 and 90 kg ha-1 mm-1 for the wet and dry years, respectively. The high Δ cultivars transpired more water, had higher yields and therefore had higher water use efficiencies compared with low Δ cultivars. (author)

  11. 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.

  12. Enhancing mechanical properties of thermoplastic polyurethane elastomers with 1,3-trimethylene carbonate, epsilon-caprolactone and L-lactide copolymers via soft segment crystallization

    Directory of Open Access Journals (Sweden)

    2011-10-01

    Full Text Available Multiblock thermoplastic polyurethane elastomers based on random and triblock copolymers were synthesized and studied. Dihydroxyl-terminated random copolymers were prepared by ring opening copolymerization of ε-caprolactone (CL and 1,3-trimethylene carbonate (TMC. The triblock copolymers were synthesized by using these random copolymers as macro-initiator for the L-lactide (L-LA blocks. These random and triblock copolymers were further reacted with 1,6-hexamethylene diisocyanate (HMDI and chain extended by 1,4-butanediol (BDO. The polymer structure and chemical composition were characterized by 1H NMR 13C NMR and SEC. Their thermal and mechanical properties were studied by using DSC and Instron microtester. Multiblock polyurethanes based on random PCL-co-PTMC copolymers showed strain recovery improvement with increasing PCL content. However, these polyurethanes were unable to sustain deformation at body temperature due to the melting of PCL crystals and low hard segments content. With the presence of crystallizable PLLA blocks, mechanical properties were improved at body temperature without compromising their good strain recovery.

  13. 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

  14. 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...

  15. Transport, compartmentation, and metabolism of homoserine in higher plant cells. Carbon-13- and phosphorus-31-nuclear magnetic resonance studies

    International Nuclear Information System (INIS)

    The transport, compartmentation, and metabolism of homoserine was characterized in two strains of meristematic higher plant cells, the dicotyledonous sycamore (Acer pseudoplatanus) and the monocotyledonous weed Echinochloa colonum. Homoserine is an intermediate in the synthesis of the aspartate-derived amino acids methionine, threonine (Thr), and isoleucine. Using 13C-nuclear magnetic resonance, we showed that homoserine actively entered the cells via a high-affinity proton-symport carrier (K(m) approximately 50-60 micromolar) at the maximum rate of 8 +/- 0.5 micromol h-1 g-1 cell wet weight, and in competition with serine or Thr. We could visualize the compartmentation of homoserine, and observed that it accumulated at a concentration 4 to 5 times higher in the cytoplasm than in the large vacuolar compartment. 31P-nuclear magnetic resonance permitted us to analyze the phosphorylation of homoserine. When sycamore cells were incubated with 100 micromolar homoserine, phosphohomoserine steadily accumulated in the cytoplasmic compartment over 24 h at the constant rate of 0.7 micromol h-1 g-1 cell wet weight, indicating that homoserine kinase was not inhibited in vivo by its product, phosphohomoserine. The rate of metabolism of phosphohomoserine was much lower (0.06 micromol h-1 g-1 cell wet weight) and essentially sustained Thr accumulation. Similarly, homoserine was actively incorporated by E. colonum cells. However, in contrast to what was seen in sycamore cells, large accumulations of Thr were observed, whereas the intracellular concentration of homoserine remained low, and phosphohomoserine did not accumulate. These differences with sycamore cells were attributed to the presence of a higher Thr synthase activity in this strain of monocot cells

  16. Carbon-13 discrimination as a criterion for identifying high water use efficiency wheat cultivars under water deficit conditions

    International Nuclear Information System (INIS)

    During four consecutive years, 20 durum wheat (Triticum durum Desf) and bread wheat (Triticum aestrivum L.) cultivars were grown under rain-fed conditions and supplementary irrigation with the objective of assessing the possibility of using 13C discrimination Δ as a criterion to screen for wheat cultivars that produce high yields and have a better water use efficiency under water deficit conditions. In all four growing season, both treatments were subjected to some water stress which was higher under rain-fed conditions and varied according to the intensity and time of rainfall. During the first growing season, and despite small differences between the two treatments in terms of the amounts of water used, the grain and straw yields as well as Δ were significantly higher in the treatment which received an irrigation at installation than in the one without irrigation. There was substantial genotypic variation in Δ. When both treatments were considered, the total above ground dry matter yield and grain yield were positively correlated with Δ although the correlation coefficient of grain yield versus Δ was not high (**). The data suggest that while a high Δ value may be used as a criterion for selection of cultivars of wheat with potential for high yield and high water use efficiency in wheat under field conditions, caution must be exercised in the selection process as the size of the canopy and the changes in environmental factors mainly soil water content, can result in changes in Δ and the yield of a cultivar. However, Δ of a genotype can also provide valuable information with respect to plant parameters responsible for the control of Δ and this information can be usefully employed in breeding programmes aimed at developing wheat cultivars high in yield and high in water use efficiency, and suitable for cultivation in arid and semi-arid regions of the tropics and sub-tropics. 11 refs, 2 figs, 2 tabs

  17. Structural effects in solvolytic reactions; carbon-13 NMR studies of carbocations†: Effect of increasing electron demand on the carbon-13 NMR shifts in substituted tert-cumyl and 1-aryl-1-cyclopentyl carbocations—correlation of the data by a new set of substituent constants, σC+*†

    OpenAIRE

    Brown, Herbert C.; Kelly, David P.; Periasamy, Mariappan

    1980-01-01

    The cationic carbon substituent chemical shifts (ΔδC+) for nine representative meta-substituted tert-cumyl carbocations are correlated satisfactorily by the σm+ substituent constants (slope ρ+ = -18.18, correlation coefficient r = 0.990). However, the substituent chemical shifts (ΔδC+) for the corresponding para derivatives are not correlated by the σp+ substituent constants. The possibility of developing a set of substituent constants capable of correlating such 13C NMR shifts was examined. ...

  18. 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

  19. 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

  20. The Contribution of the Long-term Carbon Pool to Nighttime Foliage Respiration as Revealed by a Year-long C-13 Labeling Experiment

    Science.gov (United States)

    Smith, M.; Mortazavi, B.; Chanton, J.

    2005-12-01

    Slash pine (Pinus elliottii) saplings were placed in a CO2 enrichment (~500 ppm above ambient) facility for an entire year, starting in June of 2004. The CO2 used for the enrichment, with an isotopic signature of -48‰, allowed us to track the fate of the labeled photosynthate during nighttime respiration experiments once the saplings were removed from the enrichment facility. A set of saplings subject to similar environmental conditions, but not subject to CO2 enrichment, served as controls. Nighttime respiration experiments for the labeled saplings were measured by two methods. The first procedure consisted in determining the isotopic signature of nighttime integrated (sunset to sunrise) foliage respired CO2, while the second procedure consisted in determining the pre-dawn signal. The nighttime integrated signal was determined by enclosing the entire foliage of four labeled saplings in a non-destructive manner in a 300-liter airtight chamber. Initial and final samples were collected at sunset and sunrise for CO2 concentration and 13C determination and a mass balance equation was used to determine the 13C of respired CO2. In the second procedure foliage from four labeled saplings were collected just prior to dawn and placed in a leaf-chamber. Sequential CO2 samples evolved in darkness over a 15 min period were collected for CO2 concentration and 13C determination from which a Keeling plot was constructed to determine the isotopic signature of foliage respired CO2. The isotopic signature of pre-dawn foliage respired CO2 for the control plants was also determined with an identical leaf-chamber system. Immediately after removal from the enrichment facility, the 13C of foliage respired CO2 had a pre-dawn signature of -40.2‰ and a nighttime integrated signal of -44.1‰, while the control plants had a dCf value of -25.8‰ signature. Monitoring of dCf during a 35-day period revealed a non-linear approach in dCf of the labeled plants towards the control dCf values

  1. Evaluation of bioremediation systems utilizing stable carbon isotope analysis

    International Nuclear Information System (INIS)

    Carbon, whether in an organic or inorganic form, is composed primarily of two stable isotopes, carbon-12 and carbon-13. The ratio of carbon-12 to carbon-13 is approximately 99:1. The stable carbon isotope ratios of most natural carbon materials of biological interest range from approximately 0 to -110 per mil (per-thousand) versus the PDB standard. Utilizing stable carbon isotope analysis, it is often possible to determine the source(s) of the liberated carbon dioxide, thereby confirming successful mineralization of the targeted carbon compound(s) and, if the carbon dioxide results from multiple carbon compounds, in what ratio the carbon compounds are mineralized. Basic stable isotope 'theory' recommended sampling procedures and analysis protocols are reviewed. A case study involving fuel oil presented on the application of stable carbon isotope analysis for the monitoring and evaluation of in situ bioremediation. At the site, where a field bioventing study was being conducted, multiple potential sources of carbon dioxide production existed. Additional potential applications of stable carbon isotope analysis for bioremediation evaluation and monitoring are discussed

  2. 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.

  3. Partitioning of carbon sources among functional pools to investigate short-term priming effects of biochar in soil: A (13)C study.

    Science.gov (United States)

    Kerré, Bart; Hernandez-Soriano, Maria C; Smolders, Erik

    2016-03-15

    Biochar sequesters carbon (C) in soils because of its prolonged residence time, ranging from several years to millennia. In addition, biochar can promote indirect C-sequestration by increasing crop yield while, potentially, reducing C-mineralization. This laboratory study was set up to evaluate effects of biochar on C-mineralization with due attention to source appointment by using (13)C isotope signatures. An arable soil (S) (7.9g organic C, OCkg(-1)) was amended (single dose of 10gkg(-1) soil) with dried, grinded maize stover (leaves and stalks), either natural (R) or (13)C enriched (R*), and/or biochar (B/B*) prepared from the maize stover residues (450°C). Accordingly, seven different combinations were set up (S, SR, SB, SR*, SB*, SRB*, SR*B) to trace the source of C in CO2 (180days), dissolved organic-C (115days) and OC in soil aggregate fractions (90days). The application of biochar to soil reduced the mineralization of native soil organic C but the effect on maize stover-C mineralization was not consistent. Biochar application decreased the mineralization of the non-enriched maize stover after 90days, this being consistent with a significant reduction of dissolved organic C concentration from 45 to 18mgL(-1). However, no significant effect was observed for the enriched maize stover, presumably due to differences between the natural and enriched materials. The combined addition of biochar and enriched maize stover significantly increased (twofold) the presence of native soil organic C or maize derived C in the free microaggregate fraction relative to soil added only with stover. Although consistent effects among C sources and biochar materials remains elusive, our outcomes indicate that some biochar products can reduce mineralization and solubilization of other sources of C while promoting their physical protection in soil particles. PMID:26780129

  4. High sensitivity CW-Cavity Ring Down Spectroscopy of five 13CO2 isotopologues of carbon dioxide in the 1.26-1.44 μm region (I): Line positions

    International Nuclear Information System (INIS)

    The absorption spectrum of highly enriched 13C carbon dioxide has been investigated by CW-Cavity Ring Down Spectroscopy with a setup based on fibered distributed feedback (DFB) laser diodes. By using a series of 30 DFB lasers, the CO2 spectrum was recorded in the 7029-7917 cm-1 region with a typical sensitivity of 3x10-10 cm-1. The uncertainty on the determined line positions is on the order of 8x10-4 cm-1. More than 3800 transitions with intensities as low as 1x10-29 cm/molecule were detected and assigned to the 13C16O2, 16O13C17O, 16O13C18O, 17O13C18O and 13C18O2 isotopologues. For comparison, only 104 line positions of 13C16O2 were previously reported in the literature in the considered region. The band-by-band analysis has led to the determination of the rovibrational parameters of a total of 83 bands including 56 bands of the 13C16O2 species. The measured line positions of 13C16O2 and 16O13C18O were found in good agreement with the predictions of the respective effective Hamiltonian (EH) models but the agreement degrades for the minor isotopologues. Several cases of resonance interactions were found and discussed. In the 20033-10002 band of 13C16O2, an anharmonic resonance interaction leads to deviations on the order of 0.05 cm-1 compared to the EH predictions. The existence of interpolyad interactions affecting the non-symmetric isotopologues of carbon dioxide is confirmed by the observation of two occurrences in 16O13C17O and 16O13C18O. The obtained results improve significantly the knowledge of the spectroscopy of the 13C isotopologues of carbon dioxide. They will be valuable to refine the sets of effective Hamiltonian parameters used to generate the CDSD database.

  5. The multiPrep - a new on line system for combined isotopic analysis of deuterium and 18O of water as well as 13C and 18O in individual carbonate samples

    International Nuclear Information System (INIS)

    Classical dual inlet IRMS techniques for the measurement of 18O in water, deuterium in water and 13C and 18O in carbonates have, until now involved the use of analysis dedicated on-line preparation systems or a mix of offline preparation followed by automated analysis

  6. Recent results at the SIRa test bench: diffusion properties of carbon graphite and B4C targets

    International Nuclear Information System (INIS)

    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 6He (T1/2 = 806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B4C (Boron Carbide) have also been studied. Yields of 1.5 108 pps and 106 pps for 6He and 8He has been obtained. (authors)

  7. 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)

  8. 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

  9. 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

  10. 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