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Sample records for carbon 14 target

  1. Carbon-14 waste management

    International Nuclear Information System (INIS)

    Carbon-14 occurs in nature, but is also formed in nuclear reactors. Because of its long half-life and the biological significance of carbon, releases from nuclear facilities could have a significant radiological impact. Waste management strategies for carbon-14 are therefore of current concern. Carbon-14 is present in a variety of waste streams both at reactors and at reprocessing plants. A reliable picture of the production and release of carbon-14 from various reactor systems has been built up for the purposes of this study. A possible management strategy for carbon-14 might be the reduction of nitrogen impurity levels in core materials, since the activation of 14N is usually the dominant source of carbon-14. The key problem in carbon-14 management is its retention of off-gas streams, particularly in the dissolver off-gas stream at reprocessing plants. Three alternative trapping processes that convert carbon dioxide into insoluble carbonates have been suggested. The results show that none of the options considered need be rejected on the grounds of potential radiation doses to individuals. All exposures should be as low as reasonably achievable, economic and social factors being taken into account. If, on these grounds, retention and disposal of carbon-14 is found to be beneficial, then, subject to the limitations noted, appropriate retention, immobilization and disposal technologies have been identified

  2. Compilation of carbon-14 data

    Energy Technology Data Exchange (ETDEWEB)

    Paasch, R.A.

    1985-07-08

    A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys.

  3. Compilation of carbon-14 data

    International Nuclear Information System (INIS)

    A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys

  4. Carbon 14 dating; La datation par le carbone 14

    Energy Technology Data Exchange (ETDEWEB)

    Laj, C.; Mazaud, A.; Duplessy, J.C. [CEA Saclay, Lab. des Sciences du Climat et de l' Environnement, 91 - Gif-sur-Yvette (France)

    2004-03-01

    In this article time dating based on carbon 14 method is reviewed, its limits are explained and recent improvements are presented. Carbon 14 is a by-product of the interactions of cosmic protons with air molecules. The fluctuations of the quantity of carbon 14 present in the atmosphere are responsible for the shift observed between the result given by the method and the real age. This shift appears for ages greater than 2000 years and is estimated to 1000 years for an age of 10.000 years. As a consequence carbon 14 dating method requires calibration by comparing with other methods like dendrochronology (till 11.000 years) and time dating of fossil corals (till 26.000 years and soon till 50.000 years). It is assumed that the fluctuations of carbon 14 in the atmosphere are due to: - the changes in the intensity and composition of cosmic radiations itself (due to the motion of the sun system through the galaxy or due to the explosion of a super-novae in the surroundings of the sun system); - the changes of the earth magnetic field that diverts cosmic rays; and - the changes in the interactions between the atmosphere and the oceans knowing that 40 tons of carbon 14 are dissolved in seas while only 1 ton belongs to the atmosphere. (A.C.)

  5. Carbon 14 dating method

    International Nuclear Information System (INIS)

    This document gives a first introduction to 14C dating as it is put into practice at the radiocarbon dating centre of Claude-Bernard university (Lyon-1 univ., Villeurbanne, France): general considerations and recalls of nuclear physics; the 14C dating method; the initial standard activity; the isotopic fractioning; the measurement of samples activity; the liquid-scintillation counters; the calibration and correction of 14C dates; the preparation of samples; the benzene synthesis; the current applications of the method. (J.S.)

  6. Elastic Scattering of CARBON-14 + CARBON-12, Carbon -14 + OXYGEN-16, and CARBON-14 + OXYGEN-18.

    Science.gov (United States)

    Sterbenz, Stephen Michael

    We have carried out highly detailed studies of the elastic scattering of ^{14} C from ^{12}C, ^{16}O, and ^ {18}O, in a search for resonant phenomena in heavy-ion systems of non-zero isospin and zero spin. Angular distributions from ^{14}C+ ^{12}C and ^ {14}C+^{16}O scattering were measured at ^{14} C bombarding energies ranging from 20 to 40.3 MeV in 0.35 MeV steps. ^{14}C+ ^{18}O angular distributions were measured at ^{14}C energies from 20 to 30 MeV in 0.40 MeV steps and from 22.5 to 32.5 MeV in 2.5 MeV steps. The great variety of behavior which characterizes heavy-ion scattering is clearly illustrated by our data. The ^{14}C+^ {12}C and ^{14} C+^{16}O systems both exhibit marked gross structure in their excitation functions and deep oscillatory structure with a large backward angle rise in their angular distributions. They are in sharp contrast with the ^{14} C+^{18}O system, where structure is not apparent, and cross-sections fall steeply at larger angles and higher energies. However, only in the ^{14}C+ ^{12}C system are the excitation functions strongly fragmented by intermediate width structure. The anomalous appearance of the ^{14} C+^{12}C angular distributions near 17.5 MeV (cm) does suggest the existence of a resonant state (tentatively identified as l = 10 by phase shift analysis). In our analysis, we point out that the remarkable qualitative differences among these systems may be related to open-channel systematics. We find that general characteristics of the ^{14}C+ ^{18}O data are reproduced with a strongly absorbing optical potential model, contrary to the situation in the other two systems, where a specific mechanism, such as elastic transfer, must be invoked to account for the backward rise. We have pursued analysis with a one-step DWBA elastic transfer model which was quite successful at low energies. Its underprediction of the backward rise at higher energies provides further evidence of the importance of multi-step processes in two

  7. Carbon-14 Bomb-Pulse Dating

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A

    2007-12-16

    Atmospheric testing of nuclear weapons during the 1950s and early 1960s doubled the concentration of carbon-14 atmosphere and created a pulse that labeled everything alive in the past 50 years as carbon moved up the food chain. The variation in carbon-14 concentration in time is well-documented and can be used to chronologically date all biological materials since the mid-1950s.

  8. The carbon 14 and environment; Le carbone 14 et l'environnement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This article resume the history and the properties of the carbon 14 ({sup 14}C). We also find the different origins and the produced quantities. The carbon transfers in environment are explained and so the {sup 14}C. The biological effects and the sanitary aspects are clarified. The measurements of carbon 14 are given as well its application through the dating. The waste management is tackled. (N.C.)

  9. Synthesis of carbon-14 labeled doxylamine succinate

    International Nuclear Information System (INIS)

    Doxylamine succinate, N,N-dimethyl-2-[1-phenyl-1-(2-pyridinyl)-ethoxy]ethanamine succinate is an antihistamine used primarily as a sedative. Carbon-14 labeled doxylamine succinate, required for toxicological studies, was synthesized in two steps starting from 2-benzoyl pyridine. (author)

  10. Removal of carbon-14 from irradiated graphite

    Science.gov (United States)

    Dunzik-Gougar, Mary Lou; Smith, Tara E.

    2014-08-01

    Approximately 250,000 tonnes of irradiated graphite waste exists worldwide and that quantity is expected to increase with decommissioning of Generation II reactors and deployment of Generation IV gas-cooled, graphite moderated reactors. This situation indicates the need for a graphite waste management strategy. On of the isotopes of great concern for long-term disposal of irradiated graphite is carbon-14 (14C), with a half-life of 5730 years. Study of irradiated graphite from some nuclear reactors indicates 14C is concentrated on the outer 5 mm of the graphite structure. The aim of the research presented here is to develop a practical method by which 14C can be removed. In parallel with these efforts, the same irradiated graphite material is being characterized to identify the chemical form of 14C in irradiated graphite. A nuclear-grade graphite, NBG-18, and a high-surface-area graphite foam, POCOFoam®, were exposed to liquid nitrogen (to increase the quantity of 14C precursor) and neutron-irradiated (1013 neutrons/cm2/s). During post-irradiation thermal treatment, graphite samples were heated in the presence of an inert carrier gas (with or without the addition of an oxidant gas), which carries off gaseous products released during treatment. Graphite gasification occurs via interaction with adsorbed oxygen complexes. Experiments in argon only were performed at 900 °C and 1400 °C to evaluate the selective removal of 14C. Thermal treatment also was performed with the addition of 3 and 5 vol% oxygen at temperatures 700 °C and 1400 °C. Thermal treatment experiments were evaluated for the effective selective removal of 14C. Lower temperatures and oxygen levels correlated to more efficient 14C removal.

  11. A gaseous measurement system for carbon-14 dioxide and carbon-14 methane: An analytical methodology to be applied in the evaluation of the carbon-14 dioxide and carbon-14 methane produced via microbial activity in volcanic tuff

    International Nuclear Information System (INIS)

    The objectives of this study were to develop a gaseous measurement system for the carbon-14 dioxide and carbon-14 methane produced via microbial activity or geochemical action on leachate in tuff; to determine the trapping efficiency of the system for carbon-14 dioxide; to determine the trapping efficiency of the system for carbon-14 methane; to apply the experimentally determined factors regarding the system's trapping efficiency for carbon-14 dioxide and carbon-14 methane to a trapping algorithm to determine the activity of the carbon-14 dioxide and carbon-14 methane in a mixed sample; to determine the minimum detectable activity of the measurement process in picocuries per liter; and to determine the lower limit or detection of the measurement process in counts per minute

  12. LDEO Carbon 14 Data from Selected Sea floor Cores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Carbon-14 data in this file were compiled by W.F. Ruddiman and staff at the Lamont-Doherty Earth Observatory of Columbia University. Data include 974 carbon-14...

  13. Soil metabolic transformations of carbon-14-myo-inositol, carbon-14-phytic acid and carbon-14-iron(III) phytate

    International Nuclear Information System (INIS)

    Uniformly labelled 14C-phytic acid and 14C-iron(III) phytate were synthesized from uniformly labelled 14C-myo-inositol. The three compounds were incubated in an Andosol sandy loam at 70% field capacity and 36.50C for a 12-day period. Myo-inositol, phytic acid and iron(III) phytate underwent a 61.0, 1.9 and 0% microbial oxidation respectively to CO2 during the incubation period. The rate of fixation of 14C-phytic acid was illustrated by its rapid decline in metabolism in the 12-day period. The metabolism rate of phytic was considerably reduced by the presumed formation of iron(III) and aluminium phytate. The metabolism rate of myo-inositol was reduced nine-fold after an initial rapid metabolism during the first day of incubation. The following mechanisms were observed in the soil metabolism of myo-inositol: (1) soil mineral-inositol carbon adsorption, (2) humic acid-inositol carbon adsorption, (3) the phosphorylation of myo-inositol, and (4) the epimerization of myo-inositol to chiro-inositol. The formation of (1) and (2) was found to be highly dependent upon microbial activity. Interactions (1), (2) and (3)are considered as possible mechanisms for the inhibition of the microbial oxidation of myo-inositol. The inhibition of myo-inositol oxidation via adsorption or phosphorylation is considered to be due to the chemical blockage of the stereo-specific microbial oxidative attack on the axial hydroxyl group. (author)

  14. 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.

  15. The lichens, tritium and carbon 14 integrators; Les lichens, integrateurs de tritium et de carbone 14

    Energy Technology Data Exchange (ETDEWEB)

    Daillant, O

    2007-07-01

    The present report concerns a research for the tritium and for the carbon 14 in lichens in a spirit of bio-indication: the first results appear in Daillant and al (2004 ) and additional results were presented to the congress B.I.O.M.A.P. in Slovenia, organized collectively by the institute Josef Stefan from Ljubljana and the international atomic energy agency from Vienna (Daillant and al 2003). (N.C.)

  16. The optimization of the estimation of carbon-14 in urine

    International Nuclear Information System (INIS)

    The urinalysis method for carbon-14 currently used by the bioassay laboratory of the Dosimetric Research Branch at CRNL has been tested and optimized for both sensitivity and efficiency. Urine is first treated with an enzyme that catalyses the hydrolysis of urea, the major carbon-containing component of urine; carbon dioxide is then liberated by the measured addition of excess acid and collected in 2-aminoethanol. The aminoethanol can be directly counted by the addition of a liquid scintillation cocktail. This method can be used to measure both the specific activity, (Bq/g-carbon) or the total activity of carbon-14 released from the urine sample

  17. Differential monitoring of tritium and carbon-14 compounds

    International Nuclear Information System (INIS)

    A gaseous sampling system was developed to differentially collect all major volatile forms of tritium and carbon-14 according to chemical class. These chemical forms include: tritiated forms of water, hydrogen and organics; as well as 14C-containing carbon monoxide, carbon dioxide and organics. Sampling campaigns involving the use of this differential 3H and 14C collection system have been successfully conducted at a high level liquid waste solidification plant, at a spent fuel storage facility and in the vicinity of power reactors

  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. Biomass carbon-14 ratio measured by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Measurement methods of a biomass carbon ratio in biomass products based on 14C-radiocarbon concentration have been reviewed. Determination of the biomass carbon ratio in biomass products is important to secure the reliance in the commercial market, because the 'biomass products' could contain products from petroleum. The biomass carbon ratio can be determined from percent Modern Carbon (pMC) using ASTM D6866 methods. The pMC value is calculated from the comparison between the 14C in sample and 14C in reference material. The 14C concentration in chemical products can be measured by liquid scintillation counter (LSC) and accelerator mass spectrometry (AMS). LSC can be applicable to determine the biomass carbon ratio for liquid samples such as gasoline with bioethanol (E5 or E10). On the other hand, AMS can be used to determine the biomass carbon ratio for almost all kinds of organic and inorganic compounds such as starch, cellulose, ethanol, gasoline, or polymer composite with inorganic fillers. AMS can accept the gaseous and solid samples. The graphite derived from samples included in solid phase is measured by AMS. The biomass carbon of samples derived from wood were higher than 100% due to the effect of atomic bomb test in the atmosphere around 1950 which caused the artificial 14C injection. Exact calculation methods of the biomass carbon ratio from pMC will be required for the international standard (ISO standard). (author)

  20. The preparation of glucose uniformly labelled with carbon-14

    International Nuclear Information System (INIS)

    The plant, (Zea mais, L) and culture conditions for an optimum production of glucose has been chosen. To achieve the labelling of glucose, photosynthesis and carboxylation are carried on, under an artificial atmosphere of 14CO2 produced from 14C-barium carbonate. Following photosynthesis the sugars are extracted, and then the extract purified by several methods. The purified glucose is finally, degraded and the specific radioactivity is determined in each of its carbon atoms. (Author) 37 refs

  1. Synthesis of carbon-14 labeled Taxol (paclitaxel)

    International Nuclear Information System (INIS)

    Reductive cleavage of the C13 side chain of Taxol (1, paclitaxel) followed by regioselective silylation gave 7-triethylsilylbaccatin III (4). 3-O-Triethysilylation of 5 and subsequent reaction with benzoyl chloride-C7-14C gave azetidinone 7. Coupling of 4 and 7 followed by deprotection gave 1.26 g of Taxol-N3'-14C (11) having a specific activity of 26.5 mCi/mmol and a radiochemical purity of 95%. (author)

  2. Evaluation of iron and cobalt powders as catalysts for 14C-AMS target preparation

    International Nuclear Information System (INIS)

    We present an evaluation of different brands of cobalt and iron powders used to catalyze CO2 reduction for 14C-AMS graphite targets at the KCCAMS/University of California, Irvine. The optimal catalyst is characterized by rapid graphitization, homogeneity and lack of sintering of the catalyst/carbon mixture, and contains minimal amounts of both 'modern' and 'dead' carbon. Fifteen catalyst powders were evaluated using these criteria. The results of this study indicate three good 'catalyst-candidates' with backgrounds on processed coal (Argonne Premium coal POC no. 3) samples around 60 ka BP and modern and dead carbon contamination of ≤0.2 μgC for 4-5 mg of catalyst

  3. Evaluation of carbon-14 life cycle in reactors VVER-1000

    International Nuclear Information System (INIS)

    This work is aimed at the evaluation of carbon-14 life cycle in light water reactors VVER-1000. Carbon-14 is generated as a side product in different systems of nuclear reactors and has been an issue not only in radioactive waste management but mainly in release into the environment in the form of gaseous effluents. The principal sources of this radionuclide are in primary cooling water and fuel. Considerable amount of C-14 is generated by neutron reactions with oxygen 17O and nitrogen 14N present in water coolant and fuel. The reaction likelihood and consequently volume of generated radioisotope depends on several factors, especially on the effective cross-section, concentrations of parent elements and conditions of power plant operating strategies. Due to its long half-life and high capability of integration into the environment and thus into the living species, it is very important to monitor the movement of carbon-14 in all systems of nuclear power plant and to manage its release out of NPP. The dominant forms of radioactive carbon-14 are the hydrocarbons owing to the combinations with hydrogen used for absorption of radiolytic oxygen. These organic compounds, such as formaldehyde, methyl alcohol, ethyl alcohol and formic acid can be mostly retained on ion exchange resins used in the system for purifying primary cooling water. The gaseous carbon compounds (CH4 and CO2) are released into the atmosphere via the ventilation systems of NPP. Based on the information and data obtained from different sources, it has been designed a balance model of possible carbon-14 pathways throughout the whole NPP. This model includes also mass balance model equations for each important node in system and available sampling points which will be the background for further calculations. This document is specifically not to intended to describe the best monitoring program attributes or technologies but rather to provide evaluation of obtained data and find the optimal way to upgrade

  4. Terrestrial carbon storage dynamics: Chasing a moving target

    Science.gov (United States)

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

    2015-12-01

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

  5. 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)

  6. Determination of tritium and carbon-14 in accelerator waste

    Energy Technology Data Exchange (ETDEWEB)

    Argentini, M.; Weinreich, R. [Lab. of Radio- and Environmental Chemistry, Paul Scherrer Inst., Villigen-PSI (Switzerland)

    2003-07-01

    In dismounted parts of the accelerator facilities of paul scherrer institute, tritium and {sup 14}C were determined by low-level counting after chemical separation. In graphite targets used for the production of {pi}-mesons, tritium amounts from 1.7.10{sup 8} to 6.10{sup 8} Bq/g were found; the corresponding {sup 14}C data were 6 and 9 Ci/g, respectively. In the dismantled copper beam dump of Target E, the tritium content extended up to 2.8.10{sup 6} Bq/g, but no {sup 14}C could be detected. In mechanical parts of the beam dump, consisting of iron and stainless steel, respectively, the tritium amount ranged up to 5.3.10{sup 3} Bq/g, the {sup 14}C amount from 1 to 800 Bq/g. The separation procedures are described in detail. (orig.)

  7. Carbon-14 geochemistry at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Kimberly A.; Kaplan, Daniel I.

    2013-05-10

    Carbon-14 is among the key radionuclides driving risk at the E-Area Low-Level Waste Disposal Facility on the Savannah River Site (SRS). Much of this calculated risk is believed to be the result of having to make conservative assumptions in risk calculations because of the lack of site-specific data. The original geochemical data package (Kaplan 2006) recommended that performance assessments and composite analyses for the SRS assume that {sup 14}C did not sorbed to sediments or cementitious materials, i.e., that C-14 K{sub d} value (solid:liquid concentration ratio) be set to 0 mL/g (Kaplan 2006). This recommendation was based primarily on the fact that no site-specific experimental work was available and the assumption that the interaction of anionic {sup 14}C as CO{sub 2}{sup 2-}) with similarly charged sediments or cementitious materials would be minimal. When used in reactive transport equations, the 0 mL/g Kd value results in {sup 14}C not interacting with the solid phase and moving quickly through the porous media at the same rate as water. The objective of this study was to quantify and understand how aqueous {sup 14}C, as dissolved carbonate, sorbs to and desorbs from SRS sediments and cementitious materials. Laboratory studies measuring the sorption of {sup 14}C, added as a carbonate, showed unequivocally that {sup 14}C-carbonate K{sub d} values were not equal to 0 mL/g for any of the solid phases tested, but they required several months to come to steady state. After six months of contact, the apparent K{sub d} values for a clayey sediment was 3,000 mL/g, for a sandy sediment was 10 mL/g, for a 36-year-old concrete was 30,000 mL/g, and for a reducing grout was 40 mL/g. Furthermore, it was demonstrated that (ad)sorption rates were appreciably faster than desorption rates, indicating that a kinetic sorption model, as opposed to the steady-state K{sub d} model, may be a more accurate description of the {sup 14}C-carbonate sorption process. A second study

  8. Preparation of 14C-Labeled Multi-walled Carbon Nano-tubes for Biodistribution Investigations

    International Nuclear Information System (INIS)

    A new method allowing the 14C-labeling of carboxylic acid functions of carbon nano-tubes is described. The key step of the labeling process is a de-carbonylation reaction that has been developed and optimized with the help of a screening method. The optimized process has been successfully applied to multi-walled carbon nano-tubes (MWNTs), and the corresponding 14C-labeled nano-tubes were used to investigate their in vivo behavior. Preliminary results obtained after i.v. contamination of rats revealed liver as the main target organ. Radiolabeling of NTs with a long-life radioactive nucleus like 14C, coupled to a highly sensitive autoradiographic method, that provides a unique detection threshold, will make it possible to determine for a long time period whether or not NTs remain in any organs after animal exposure. (authors)

  9. Carbon 14 dating method; Methode de datation par le carbone 14

    Energy Technology Data Exchange (ETDEWEB)

    Fortin, Ph

    2000-07-01

    This document gives a first introduction to {sup 14}C dating as it is put into practice at the radiocarbon dating centre of Claude-Bernard university (Lyon-1 univ., Villeurbanne, France): general considerations and recalls of nuclear physics; the {sup 14}C dating method; the initial standard activity; the isotopic fractioning; the measurement of samples activity; the liquid-scintillation counters; the calibration and correction of {sup 14}C dates; the preparation of samples; the benzene synthesis; the current applications of the method. (J.S.)

  10. Progressive extraction method applied to isotopic exchange of carbon-14

    International Nuclear Information System (INIS)

    Isotopic exchange in natural settings is essentially an irreversible process, so that it progresses continuously until there is complete isotopic equilibrium. In soils, this process involves interaction between isotopes in the liquid and solid phases, and complete isotopic equilibrium may take a very long time. Measurements after partial isotopic exchange have been used to characterize the labile fraction of elements in soils. We describe a method to characterize the extent of isotopic exchange, with application here to incorporation of inorganic carbon-14 (14C) into mineral carbonates and organic matter in soils. The procedure uses a continuous addition of extractant, acid, or H2O2in the examples presented here, coupled with sequential sampling. The method has been applied to demonstrate the degree of isotopic exchange in soil. The same strategy could be applied to many other elements, including plant nutrients. (author)

  11. A detective from the past called carbon 14

    International Nuclear Information System (INIS)

    The analysis is carried out using Radiometry or Accelerator mass spectrometry. After the system allowing to date the age of any organic rest - whether a fossil, a wood fragment, a parchment or a seed - is an isotope called carbon-14. An atom that comes from reactions nuclear produced in the atmosphere and cosmic-ray-induced they interact with oxygen to form carbon dioxide. This element they absorb it plants in photosynthesis and then passes to the animals remained almost unchanged during the life of the organism. to the meet the initial ratio of c-14 that had been in the atmosphere before his death, the remains that are left in it determine the elapsed time. (Author)

  12. Carbon budget of a marine phytoplankton-herbivore system with carbon-14 as a tracer

    Energy Technology Data Exchange (ETDEWEB)

    Copping, A.E.; Lorenzen, C.J.

    1980-09-01

    Adult female and stage V Calanus pacificus were fed /sup 14/C-labeled phytoplankton in the laboratory in the form of monospecific cultures and natural populations. A carbon budget was constructed by following the /sup 14/C activity and the specific activity, over 48 h, in the phytoplankton, copepod, dissolved organic, dissolved inorganic, and fecal carbon compartments. The average incorporation of carbon into the copepod's body was 45% of the phytoplankton carbon available. Of the phytoplankton carbon, 27% appeared as dissolved organic carbon, 24% as dissolved inorganic carbon, and 3 to 4% in the form of fecal pellets. All of the tracer was recovered at the end of the experiments. The specific activity of the phytoplankton compartment was constant throughout each experiment. The other compartments had initial specific activities of zero, or close to zero, and increased throughout the experiment. In most experiments, the copepod specific activity equalled that of the phytoplankton at the end of 48 h, while the dissolved organic carbon, dissolved inorganic carbon, and fecal specific activities remained well below that of the phytoplankton.

  13. Radiative Neutron Capture on Carbon-14 in Effective Field Theory

    OpenAIRE

    Rupak, Gautam; Fernando, Lakma; Vaghani, Akshay

    2012-01-01

    The cross section for radiative capture of neutron on carbon-14 is calculated using the model-independent formalism of halo effective field theory. The dominant contribution from E1 transition is considered, and the cross section is expressed in terms of elastic scattering parameters of the effective range expansion. Contributions from both resonant and non-resonant interaction are calculated. Significant interference between these leads to a capture contribution that deviates from simple Bre...

  14. 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

  15. A detective from the past called carbon 14; Un detective del pasado llamado carbono 14

    Energy Technology Data Exchange (ETDEWEB)

    Trintan, R. M.

    2015-07-01

    The analysis is carried out using Radiometry or Accelerator mass spectrometry. After the system allowing to date the age of any organic rest - whether a fossil, a wood fragment, a parchment or a seed - is an isotope called carbon-14. An atom that comes from reactions nuclear produced in the atmosphere and cosmic-ray-induced they interact with oxygen to form carbon dioxide. This element they absorb it plants in photosynthesis and then passes to the animals remained almost unchanged during the life of the organism. to the meet the initial ratio of c-14 that had been in the atmosphere before his death, the remains that are left in it determine the elapsed time. (Author)

  16. 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

  17. 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

  18. Development of an Optimized Activatable MMP-14 targeted SPECT Imaging Probe

    OpenAIRE

    Watkins, Gregory A.; Jones, Ella Fung; Shell, M. Scott; VanBrocklin, Henry F.; Pan, Mei-Hsiu; Hanrahan, Stephen M.; Feng, Jin Jin; He, Jiang; Sounni, Nor Eddine; Dill, Ken A.; Contag, Christopher H.; Coussens, Lisa M; Franc, Benjamin L.

    2008-01-01

    Matrix Metalloproteinase-14 (MT1-MMP or MMP-14) is a membrane-associated protease implicated in a variety of tissue remodeling processes and a molecular hallmark of select metastatic cancers. The ability to detect MMP-14 in vivo would be useful in studying its role in pathologic processes and may potentially serve as a guide for the development of targeted molecular therapies. Four MMP-14 specific probes containing a positively charged cell penetrating peptide (CPP) d-arginine octamer (r8) li...

  19. Biosphere structure, carbon sequestering potential and the atmospheric C-14 carbon record

    Energy Technology Data Exchange (ETDEWEB)

    Goudriaan, J.

    1992-08-01

    The behaviour of a numerical model for the global carbon cycle is elucidated by a simple analytical model for the biosphere. In the period 1980-1990 the ocean is estimated to have absorbed 33% of the total CO{sub 2} emission to the atmosphere in that same period. Net deforestation was responsible for 12-17% of this total emission rate, whereas the CO{sub 2}-fertilization effect caused a re-absorption of 20-25%. Aggregation of the above-ground biosphere into a single pool in the model caused an overestimation of the CO{sub 2}-fertilization effect. Also, the estimate of this rate increased when the fraction of carbon assumed to remain after the transformation of litter into humus was increased, but the rate was little influenced by the model structure for soil organic carbon. A larger estimate for carbon uptake in the biosphere (Tans, Fung, and Takahashi, 1990) must be compensated by a reduced uptake in the ocean to arrive at a carbon balance. To do this, either the exchange rate between the upper mixed ocean layer and deep sea, or between ocean surface and atmosphere, should be reduced. In addition, a good match to the observed time-course of C-14 carbon in the atmosphere must be preserved by the model. The C-14 time-course did not remain well-matched if the atmosphere-ocean surface exchange was reduced, but it was hardly disturbed at all if the exchange rate with the deep sea was reduced.

  20. The preparation of glucose uniformly labelled with carbon-14; Preparacion de glucosa uniformemente marcada con carbono-14

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M. D.; Suarez, C.; Rodrigo, M. E.

    1978-07-01

    The plant, (Zea mais, L) and culture conditions for an optimum production of glucose has been chosen. To achieve the labelling of glucose, photosynthesis and carboxylation are carried on, under an artificial atmosphere of 14CO{sub 2} produced from 14{sup C}-barium carbonate. Following photosynthesis the sugars are extracted, and then the extract purified by several methods. The purified glucose is finally, degraded and the specific radioactivity is determined in each of its carbon atoms. (Author) 37 refs.

  1. Progress on polarized target materials with pure carbon background

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Supuran, Claudiu T

    2016-01-01

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

  3. Legionella pneumophila Carbonic Anhydrases: Underexplored Antibacterial Drug Targets

    Directory of Open Access Journals (Sweden)

    Claudiu T. Supuran

    2016-06-01

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

  4. 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

  5. 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

  6. Synthesis of carbon-14 labelled indolic 5HT{sub 1} receptor agonists

    Energy Technology Data Exchange (ETDEWEB)

    Waterhouse, Ian; Cable, K.M.; Fellows, Ian; Wipperman, M.D.; Sutherland, D.R. [Glaxo Wellcome Research and Development, Stevenage (United Kingdom). Isotope Chemistry Unit

    1996-11-01

    Syntheses of carbon-14 labelled versions of indolic 5HT{sub 1} agonists sumatriptan (GR43175), GR40370 and naratriptan (GR85548) are described. Introduction of the label via cyanation of ketoformanilides, formed by oxidative cleavage of an indole ring, ensured incorporation of carbon-14 at the metabolically stable C-2 position of the indole. (author).

  7. Effect of dead carbon on the 14C dating of the speleothem

    Institute of Scientific and Technical Information of China (English)

    CAI Yanjun; Warren Beck; PENG Zicheng; ZHANG Zhaofeng

    2005-01-01

    Based on the comparison of dating results among high-precision TIMS U-series and AMS 14C as well as the published 14C dating results and their band counting ages (i.e. calendar ages), this paper discusses the effect of dead carbon on the speleothem 14C dating. The result shows that the fraction of incorporated dead carbon during the formation of speleothem varies. The change in the fraction of dead carbon would result in big deviation in the 14C age of the speleothem. It is indispensable to take the dead carbon into consideration when dating the speleothem using the 14C method or studying the atmospheric 14C concentration during the past with the speleothem.

  8. Effect of industrial fuel combustion on the carbon-14 level of atmospheric CO2

    International Nuclear Information System (INIS)

    As was previously noticed in 1953 by SUESS, the radiocarbon content of atmospheric CO2 was slightly lower in the 20th century (before the increase in the carbon-14 level due to the addition of artificial 14C) than at the time before the beginning of the industrial revolution in the 19th century. An exact knowledge of the magnitude of this effect is of interest in connection with the question of the rate of isotope exchange between atmospheric CO2 and the bicarbonates of the oceans. However, the radiocarbon level in the CO2 of the atmosphere is also subject to natural fluctuations caused by a variable cosmic-ray production rate of carbon-14. To investigate this the authors have cross-correlated sunspot numbers (as indicators of cosmic-ray activity) with the carbon-14 level in wood, and have detected a significant coherence between the two time series. The observed coherence permits an extrapolation of the natural carbon-14 values beyond the time of the beginning of artificial combustion of fossil fuel, around 1880. The results show that the observed small decrease in the carbon-14 level is somewhat affected by the increase of the production rate of carbon-14, as a consequence of relatively low solar activity during the preceding decades. The effect of industrial fuel combustion upon the carbon-14 level of the atmosphere can then be estimated for the Northern Hemisphere to be in the vicinity of -3%. (author)

  9. Laboratory Experiments to Evaluate Matrix Diffusion of Dissolved Organic Carbon Carbon-14 in Southern Nevada Fractured-rock Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L. [Nevada University, Reno, NV (United States). Desert Research Institute; Fereday, Wyatt [Nevada University, Reno, NV (United States). Desert Research Institute

    2016-05-01

    Dissolved inorganic carbon (DIC) carbon-14 (14C) is used to estimate groundwater ages by comparing the DIC 14C content in groundwater in the recharge area to the DIC 14C content in the downgradient sampling point. However, because of chemical reactions and physical processes between groundwater and aquifer rocks, the amount of DIC 14C in groundwater can change and result in 14C loss that is not because of radioactive decay. This loss of DIC 14C results in groundwater ages that are older than the actual groundwater ages. Alternatively, dissolved organic carbon (DOC) 14C in groundwater does not react chemically with aquifer rocks, so DOC 14C ages are generally younger than DIC 14C ages. In addition to chemical reactions, 14C ages may also be altered by the physical process of matrix diffusion. The net effect of a continuous loss of 14C to the aquifer matrix by matrix diffusion and then radioactive decay is that groundwater appears to be older than it actually is. Laboratory experiments were conducted to measure matrix diffusion coefficients for DOC 14C in volcanic and carbonate aquifer rocks from southern Nevada. Experiments were conducted using bromide (Br-) as a conservative tracer and 14C-labeled trimesic acid (TMA) as a surrogate for groundwater DOC. Outcrop samples from six volcanic aquifers and five carbonate aquifers in southern Nevada were used. The average DOC 14C matrix diffusion coefficient for volcanic rocks was 2.9 x 10-7 cm2/s, whereas the average for carbonate rocks was approximately the same at 1.7 x 10-7 cm2/s. The average Br- matrix diffusion coefficient for volcanic rocks was 10.4 x 10-7 cm2/s, whereas the average for carbonate rocks was less at 6.5 x 10-7 cm2/s. Carbonate rocks exhibited greater variability in

  10. Dissolved Organic Carbon 14C in Southern Nevada Groundwater and Implications for Groundwater Travel Times

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L.; Fereday, Wyall; Thomas, James M

    2016-08-01

    Dissolved inorganic carbon (DIC) carbon-14 (14C) ages must be corrected for complex chemical and physical reactions and processes that change the amount of 14C in groundwater as it flows from recharge to downgradient areas. Because of these reactions, DIC 14C can produce unrealistically old ages and long groundwater travel times that may, or may not, agree with travel times estimated by other methods. Dissolved organic carbon (DOC) 14C ages are often younger than DIC 14C ages because there are few chemical reactions or physical processes that change the amount of DOC 14C in groundwater. However, there are several issues that create uncertainty in DOC 14C groundwater ages including limited knowledge of the initial (A0) DOC 14C in groundwater recharge and potential changes in DOC composition as water moves through an aquifer. This study examines these issues by quantifying A0 DOC 14C in recharge areas of southern Nevada groundwater flow systems and by evaluating changes in DOC composition as water flows from recharge areas to downgradient areas. The effect of these processes on DOC 14C groundwater ages is evaluated and DOC and DIC 14C ages are then compared along several southern Nevada groundwater flow paths. Twenty-seven groundwater samples were collected from springs and wells in southern Nevada in upgradient, midgradient, and downgradient locations. DOC 14C for upgradient samples ranged from 96 to 120 percent modern carbon (pmc) with an average of 106 pmc, verifying modern DOC 14C ages in recharge areas, which decreases uncertainty in DOC 14C A0 values, groundwater ages, and travel times. The HPLC spectra of groundwater along a flow path in the Spring Mountains show the same general pattern indicating that the DOC compound composition does not change along this flow path. Although DOC concentration decreases from recharge-area to downgradient groundwater, the organic compounds are similar, indicating that DOC 14C is unaffected by other processes such as microbial

  11. Report on Carbon-14 generation and release at some of the Hanford reactors

    Energy Technology Data Exchange (ETDEWEB)

    Barton, G.B.

    1964-12-14

    The Hanford graphite-moderated reactors have an enclosed gas circulation system to maintain control of the composition of gas atmosphere in the graphite stack. This investigation was undertaken to answer several questions concerning the generation and release of Carbon-14 in the operation of these graphite moderated reactors. The principle question was: Will an increase in the nitrogen content of the reactor atmosphere increase the release of Carbon-14 sufficiently to create a health hazard. Other questions were: (1) What are the main sources and the main release routes. (2) How much does carbon-14 build up in the graphite in the reactor stack. and (3) Is the total release of carbon-14 to the atmosphere sufficient to enhance the /sup 14/C levels in the vegetation surrounding the reactors.

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

    Energy Technology Data Exchange (ETDEWEB)

    Seidl, P.A.

    1985-02-01

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

  13. Stable Isotopic Evidence for a Pedogenic Origin of Carbonates in Trench 14 near Yucca Mountain, Nevada.

    Science.gov (United States)

    Quade, J; Cerling, T E

    1990-12-14

    Layered carbonate and silica encrust fault fractures exposed in Trench 14 near Yucca Mountain, site of the proposed high-level nuclear waste repository in southern Nevada. Comparison of the stable carbon and oxygen isotopic compositions of the fracture carbonates with those of modern soil carbonates in the area shows that the fracture carbonates are pedogenic in origin and that they likely formed in the presence of vegetation and rainfall typical of a glacial climate. Their isotopic composition differs markedly from that of carbonate associated with nearby springs. The regional water table therefore remained below the level of Trench 14 during the time that the carbonates and silica precipitated, a period probably covering parts of at least the last 300,000 years. PMID:17818282

  14. Carbon-14 in lunar soil and in meteorites

    Science.gov (United States)

    Fireman, E. L.

    1978-01-01

    C-14 was measured in grain-size fractions of lunar soil 10084 and in samples of the Bruderheim chondrite and of several meteorites recently found in Antarctica (Allan Hills no. 5, 6, and 8). Temperature-release patterns were investigated. It was found that C-14 is released at temperatures below melting from small soil grains (less than 74 microns), but not from meteorites or from large soil grains. Below-melting C-14 contents increase with decreasing grain size in a manner similar to solar-wind-implanted rare-gas isotope contents (Eberhardt et al., 1970), whereas the C-14 released above melting temperatures is independent of grain size, suggesting that below-melting C-14 is solar-wind-implanted and above-melting C-14 is the result of cosmic ray spallations. The activity of C-14 in lunar samples is half that measured in the Bruderheim meteorite, which fell on May 4, 1970. No C-14 activity was observed in the Allan Hills chondrites; the C-14 limits suggest that these meteorites fell more than 25,000 years ago.

  15. Consideration of R2Fe14B layers as targets with polarized electrons

    NARCIS (Netherlands)

    Hoogduin, JM; van Klinken, J

    1998-01-01

    Thin layers of R2Fe14B magnets (R = rare earth) can be magnetized perpendicularly to their planes and can be used as targets of polarized electrons with polarization of approximate to 4% to facilitate Moller/Bhabha and Compton polarimetry of electrons/positrons and photons, respectively. (C) 1998 El

  16. Radiocarbon 14C differentiation of sparkling and carbonated wines

    International Nuclear Information System (INIS)

    Specific 14C-activities, percent of modern 14C-activity, and calculated percent of fermentation CO2 are presented for CO2 contained in commercial sparkling wines, labeled as champagne or produced by the bulk (charmat) process. These data are given for the production years 1976-1982. The survey encompassed effervescent wines produced in Spain, Italy, West Germany, California, and New York. Addition of synthetic CO2 to approximately 40 samples represented as sparkling wines was indicated by low 14C-activities of CO2 in these wines. Data for 14C-activity were also presented for the ethanol distilled from sparkling wines for the years 1977-1980. In all cases, the 14C-activity of ethanol was appropriate to the year of vintage

  17. Synthesis of the monosodium salt of carbon-14 labeled paclitaxel (Taxol) 2`-ethyl carbonate 7-phosphonooxymethyl ether, a potential prodrug of paclitaxel

    Energy Technology Data Exchange (ETDEWEB)

    Dischino, D.D.; Shuhui Chen; Golik, Jerzy; Walker, D.W.; Wong, H.S.L. [Bristol-Myers Squibb Co., Richard L. Gelb Center for Research and Development, Wallingford, CT (United States)

    1997-02-01

    The monosodium salt of carbon-14 labeled paclitaxel (Taxol) [N3`-{sup 14}COPh] 2`-ethyl carbonate 7-phosphonooymethyl ether, was prepared from C-14 labeled paclitaxel [N3`-{sup 14}COPh] in 5 steps. The radiochemical purity of the final product was greater than 99% and the specific activity was 25 {mu}Ci/mg. (author).

  18. Synthesis of δ-aminolevulic acid. Application to the introduction of carbon-14 and of tritium

    International Nuclear Information System (INIS)

    Several new syntheses of δ aminolevulic acid (δ A.L.A.) have been studied. 14C-4 δ - aminolevulic acid has been obtained from 14C allylacetic carboxylic acid with a yield of 30 per cent with respect to barium carbonate and with a specific activity of 32 mCi/mM. The 14C-1 or 14C-2 δ-A.L.A. has been prepared from the 14C-1 or 14C-2 acetate with a yield of 55 per cent with respect to the acetate. Finally the tritiated δ-A.L.A. has been obtained for the first time by tritiation of ethyl phthalimidodehydrolevulate. (author)

  19. Tracing terrestrial carbon: a novel application of ∆14C in a humic lake

    Science.gov (United States)

    Keaveney, Evelyn; Reimer, Paula J.; Foy, Robert H.

    2016-04-01

    Lakes play an important yet underrated role in global carbon cycles. Terrestrial carbon (C) is buried and/or remineralised in significant quantities, and lake function may also be affected by catchment inputs with potential feedbacks for regional and global C cycling. Changing deposition chemistry, land use and climate induced impacts on hydrology will affect soil biogeochemistry, terrestrial C export, and hence lake ecology. Autochthonous production in lakes is based on dissolved inorganic C (DIC). DIC in alkaline lakes is partially derived from weathering of carbonaceous bedrock, a proportion of which is 14C-free. The low 14C activity yields an artificial age offset leading samples to appear hundreds to thousands of years older than their actual age. Dissolved organic carbon (DOC) and particulate organic carbon (POC) can contain terrestrial inputs. The terrestrial inputs can be labile or detrital and their age depends to a first order on their depth in catchment soil/peat stocks. We present a pilot study that uses the radiocarbon (∆14C) method to determine the source of carbon buried in the surface sediment of Lower Lough Erne, a humic, alkaline lake in northwest Ireland. ∆14C, δ13C and δ15N values were measured from phytoplankton and other biota, dissolved inorganic, dissolved organic and particulate organic carbon. A novel radiocarbon method, Stepped Combustion1 was used to estimate the degree of the burial of terrestrial carbon in surface sediment, collected in 2011. The ∆14C values of the low temperature fractions were comparable to algal ∆14C, while the high temperature fractions were 14C-depleted (older than bulk sediment). The ∆14C end-member model indicated that ~64% of carbon in surface sediment was derived from detrital terrestrial carbon. The same proportion of detrital/labile carbon was found in surface sediment of Upper Lough Erne in 2014, despite the differences in lake type and collection date. The use of ∆14C in conjunction with

  20. Asphalt in carbon-14-dated archaeological samples from Terqa, Syria

    International Nuclear Information System (INIS)

    The results are reported of an organic geochemical study to verify contamination in 14C dated archaeological samples, which could account for much older apparent ages than expected. The data indicate that ancient asphalt must be the source of contamination, showing that caution should be exercised, in interpreting 14C dates of archaeological samples from areas containing asphalt or other fossil fuel deposits. (U.K.)

  1. Results of interagency effort to determine carbon-14 source term in low-level radioactive waste

    International Nuclear Information System (INIS)

    A preliminary estimate of the risks from the shallow land disposal of low-level radioactive wastes by EPA in 1984-1985 indicated that Carbon-14 caused virtually all of the risk and that these risks were relatively high. Therefore, an informal interagency group, which included the US Department of Energy, US Geological Survey, US Nuclear Regulatory Commission, and US Environmental Protection Agency, formed in 1985 to obtain up-to-date information on the activity and chemical form of Carbon-14 in the different types of LLW and how Carbon-14 behaves after disposal. The EPA acted as a focal point for collating the information collected by all of the Agencies and will publish a report in Fall 1986 on the results of the Carbon-14 data collection effort. Of particular importance, the study showed that Carbon-14 activity in LLW was overestimated approximately 2000%. This paper summarizes results of the Carbon-14 data collection effort. 40 references, 1 figure, 3 tables

  2. Carbon 14 absorption and translocation in sugar cane

    International Nuclear Information System (INIS)

    Plant-cane stools were labelled with sup(14) CO sub(2), in the field, at Goiana-PE, Brazil, when 3, 7 and 11 months old. Each stool was enclosed in a chamber with sup(14) CO sub(2) for 90 minutes. The sub(14) C photosynthetic were measured in leaves, stalks, roots and soil 24 hours after labelling. Roots were divided into alive and dead and soil into rhizosphere and outer soil. At the end of the labelling period at 3, 7 and 11 months, 2, 19 and 1% of the initial sup(14) CO sub(2) were recovered in the plant and the soil. The low recovery of sub(14) C at 3 months could be attribute to losses by respiration and lack of sampling of the top growing point. The low CO sub(2) fixation and losses at first sampling in the 7 month old labelling were attributed to low light intensity during the day of labelling. Most of the recovered sub(14) C (>80%) was founded in the leaves but all plant parts received labelled photosynthetic. At 3 months, most of the sub(14) C translocated from the leaves went to the living roots (83%); at 7 and 11 months it went to the stalks (69 and 66%). While the roots received less than 2%. Root masses did not vary consistently along the plant cycle and dead root masses were always less than 10% of the total root mass. Radioactivity in the dead roots was always very low. These results suggest that the root system have a low turnover rate after 3 months old. (author)

  3. Atmospheric nuclear weapons test history narrated by carbon-14 in human teeth

    International Nuclear Information System (INIS)

    The atmospheric testing of nuclear weapons since 1945 caused a significant increase in the concentration of atmospheric 14C. The 14C concentration in plants that assimilate 14C directly by photosynthesis reflects the atmospheric 14C concentration. Carbon-14 is then transferred into the human body through the food chain. Based on animal experiments, the collagen in human teeth is metabolically inert after its formation. This implies that the collagen of each tooth retains the 14C concentration which reflects the 14C concentration in the blood at the time collagen metabolism ceased. The distribution of the 14C concentration in the collagen of teeth from subjects of various ages would follow a pattern similar to that shown by soft tissues. In this paper the authors elucidate the relationship between the number of nuclear weapon tests and the distribution of 14C concentration in teeth

  4. 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.

  5. Carbon-14 ages of Allan Hills meteorites and ice

    Science.gov (United States)

    Fireman, E. L.; Norris, T.

    1982-01-01

    Allan Hills is a blue ice region of approximately 100 sq km area in Antarctica where many meteorites have been found exposed on the ice. The terrestrial ages of the Allan Hills meteorites, which are obtained from their cosmogenic nuclide abundances are important time markers which can reflect the history of ice movement to the site. The principal purpose in studying the terrestrial ages of ALHA meteorites is to locate samples of ancient ice and analyze their trapped gas contents. Attention is given to the C-14 and Ar-39 terrestrial ages of ALHA meteorites, and C-14 ages and trapped gas compositions in ice samples. On the basis of the obtained C-14 terrestrial ages, and Cl-36 and Al-26 results reported by others, it is concluded that most ALHA meteorites fell between 20,000 and 200,000 years ago.

  6. Synthesis of carbon-14 labeled Taxol (paclitaxel). [Anticancer agent

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.G.; Swigor, J.E. (Bristol-Myers Squibb Co., Syracuse, NY (United States). Pharmaceutical Research Inst.); Kant, Joydeep; Schroeder, D.R. (Bristol-Myers Squibb Co., Wallingford, CT (United States). Pharmaceutical Research Inst.)

    1994-10-01

    Reductive cleavage of the C13 side chain of Taxol (1, paclitaxel) followed by regioselective silylation gave 7-triethylsilylbaccatin III (4). 3-O-Triethysilylation of 5 and subsequent reaction with benzoyl chloride-C7-[sup 14]C gave azetidinone 7. Coupling of 4 and 7 followed by deprotection gave 1.26 g of Taxol-N3'-[sup 14]C (11) having a specific activity of 26.5 mCi/mmol and a radiochemical purity of 95%. (author).

  7. 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

  8. Targeting Ergosterol Biosynthesis in Leishmania donovani: Essentiality of Sterol 14alpha-demethylase

    OpenAIRE

    Laura-Isobel McCall; Amale El Aroussi; Jun Yong Choi; Vieira, Debora F.; Geraldine De Muylder; Johnston, Jonathan B.; Steven Chen; Danielle Kellar; Jair L Siqueira-Neto; Roush, William R.; Larissa M. Podust; McKerrow, James H.

    2015-01-01

    Leishmania protozoan parasites (Trypanosomatidae family) are the causative agents of cutaneous, mucocutaneous and visceral leishmaniasis worldwide. While these diseases are associated with significant morbidity and mortality, there are few adequate treatments available. Sterol 14alpha-demethylase (CYP51) in the parasite sterol biosynthesis pathway has been the focus of considerable interest as a novel drug target in Leishmania. However, its essentiality in Leishmania donovani has yet to be de...

  9. Displacement of carbon-14 labelled amino acids from leaves

    International Nuclear Information System (INIS)

    The displacement of amino acids from nature leaves was investigated. The amino acids (Ala, Asn, Asp, Glu, Gln, Val, Leu, Lys, Ser, Pro) were applied on the leaves in L-form, uniformly labelled with 14C, and the type and direction of displacement have been observed. Most of the studies have been carried out on bush beans aged 3 to 4 weeks. The experiments were carried out in climatic chambers; in one case, barley plants just reaching maturity were used. In order to find out whether the applied amino acids were also displaced in their original form, freeze-dried plants were extracted and the 14C activity of the various fraction was determined. The radioactivity of some free amino acids was determined after two-dimensional separation by thin film chromatography. (orig./HK)

  10. Determination of carbon-14 in environmental level, solid reference materials

    Energy Technology Data Exchange (ETDEWEB)

    Blowers, Paul, E-mail: paul.blowers@cefas.co.uk [Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, NR33 0HT (United Kingdom); Caborn, Jane, E-mail: jane.a.caborn@nnl.co.uk [NNL, Springfields, Salwick, Preston, Lancashire, PR4 0XJ (United Kingdom); Dell, Tony [Veterinary Laboratories Agency, New Haw, Addlestone, Surrey, KT15 3NB (United Kingdom); Gingell, Terry [DSTL, Radiation Protection Services, Crescent Road, Alverstoke, Gosport, Hants, PO12 2DL (United Kingdom); Harms, Arvic [National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW (United Kingdom); Long, Stephanie [Radiological Protection Institute of Ireland, 3 Clonskeagh Square, Clonskeagh Road, Dublin 14, Ireland (United Kingdom); Sleep, Darren [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP (United Kingdom); Stewart, Charlie [UKAEA (Waste Management Group), Chemical Support Services, D1310/14, Dounreay, Thurso, Caithness, KW14 7TZ (United Kingdom); Walker, Jill [Radiocarbon Dating, The Old Stables, East Lockinge, Wantage, Oxon OX12 8QY (United Kingdom); Warwick, Phil E. [GAU-Radioanalytical, National Oceanography Centre Southampton, European Way, Southampton, SO14 3ZH (United Kingdom)

    2011-10-15

    An intercomparison exercise to determine the {sup 14}C activity concentrations in a range of solid, environmental level materials was conducted between laboratories in the UK. IAEA reference materials, C2, C6 and C7, and an in-house laboratory QA material were dispatched in 2006 to ten laboratories comprising of members of the Analyst Informal Working Group (AIWG) and one other invited party. The laboratories performed the determinations using a number of techniques, and using the results each one was evaluated in terms of levels of precision, sensitivity and limits of detection. The results of the study show that all techniques are capable of successfully analysing {sup 14}C in environmental level materials, however, a shortage of certified environmental reference materials exists. The suitability of the IAEA reference materials and other material for use as reference materials was also assessed.

  11. Determination of carbon-14 in environmental level, solid reference materials

    International Nuclear Information System (INIS)

    An intercomparison exercise to determine the 14C activity concentrations in a range of solid, environmental level materials was conducted between laboratories in the UK. IAEA reference materials, C2, C6 and C7, and an in-house laboratory QA material were dispatched in 2006 to ten laboratories comprising of members of the Analyst Informal Working Group (AIWG) and one other invited party. The laboratories performed the determinations using a number of techniques, and using the results each one was evaluated in terms of levels of precision, sensitivity and limits of detection. The results of the study show that all techniques are capable of successfully analysing 14C in environmental level materials, however, a shortage of certified environmental reference materials exists. The suitability of the IAEA reference materials and other material for use as reference materials was also assessed.

  12. 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 ...

  13. Determination of Carbon-14 in environmental samples by mixing 14CO{sub 2} with a liquid scintillator; Determinacion de carbono-14 en muestras ambientales por incorporacion de 14CO{sub 2} a un centelleador liquido

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M. R.; Gomez, V.; Heras, M. C.; Beltran, M. A.

    1990-07-01

    A method for the determination of Carbon-14 (14CO2) in environmental samples has been developed. The method use the direct absorption of the carbon dioxide into Carbosorb, followed with incorporation of the mixture (Carbosorb-CO2) to the liquid scintillator. The results obtained to apply this method and the benzene synthesis, usual in our laboratory, are discussed and compared. The method of collection of atmospheric samples is also described. (Author) 10 refs.

  14. 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.

  15. Two dimensional model study of atmospheric transport using carbon-14 and strontium-90 as inert tracers

    International Nuclear Information System (INIS)

    This study tests the transport processes in the LLNL two-dimensional chemical-radiative-transport model using recently reanalyzed carbon-14 and strontium-90 data. These radioactive tracers were produced bythe atmospheric nuclear bomb tests of 1952--58 and 1961--62, and they were measured at a few latitudes up to 35 kilometers over the period 1955--1970. Selected horizontal and vertical eddy diffusion coefficients were varied in the model to test their sensitivity to short and long term transpose of carbon-14. A sharp transition of Kzz and Kyy through the tropopause, as opposed to a slow transition between the same limiting values, shows a distinct improvement in the calculated carbon-14 distributions, a distinct improvement in the calculated seasonal and latitudinal distribution of ozone columns (relative to TOMS observations), and a very large difference in the calculated ozone reduction by a possible fleet of High Speed Civil Transports. Calculated northern hemisphere carbon-14 is more sensitive to variation of Kyy than are global ozone columns. Strontium-90 was used to test the LLNL tropopause height at four different latitudes. Starting with the 1960 background distribution of carbon-14, we calculate the input of carbon-14 as the sum of each nuclear test of the 1961--62 series, using two bomb-cloud rise models. With the Seitz bomb-rise formulation in the LLNL model, we find good agreement between calculated and observedcarbon-14 (with noticeable exceptions at the north polar tropopause and the short-term mid-latitude mid-stratosphere) between 1963 and 1970

  16. Characteristics study of a system for carbon 14 dating

    International Nuclear Information System (INIS)

    The developing of a radiocarbon dating laboratory, specially built to deal with carbonate samples from underground water, at the Institute de Energia Atomica, required the optimization of a benzene synthetizer, and also of the operative conditions of the liquid scintillator counter, used in sample measurements. An average yield of about 70% was obtained in our benzenic synthesis. If more refined conditions were used, better results could have been obtained, but the reported yield is good enough for our necessities. A comparison of the ages of several shell samples was done between the Geochronology Laboratory, belonging to the Instituto de Geociencias, at Sao Paulo University and our dating laboratory. The agreement between the results was fairly good, according to the precision required

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

    Science.gov (United States)

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

    2013-08-27

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

  18. 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.

  19. 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

  20. 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.

  1. Carbon-14 transfer into rice plants from a continuous atmospheric source: observations and model predictions

    International Nuclear Information System (INIS)

    Carbon-14 (14C) is one of the most important radionuclides from the perspective of dose estimation due to the nuclear fuel cycle. Ten years of monitoring data on 14C in airborne emissions, in atmospheric CO2 and in rice grain collected around the Tokai reprocessing plant (TRP) showed an insignificant radiological effect of the TRP-derived 14C on the public, but suggested a minor contribution of the TRP-derived 14C to atmospheric 14C concentrations, and an influence on 14C concentrations in rice grain at harvest. This paper also summarizes a modelling exercise (the so-called rice scenario of the IAEA's EMRAS program) in which 14C concentrations in air and rice predicted with various models using information on 14C discharge rates, meteorological conditions and so on were compared with observed concentrations. The modelling results showed that simple Gaussian plume models with different assumptions predict monthly averaged 14C concentrations in air well, even for near-field receptors, and also that specific activity and dynamic models were equally good for the prediction of inter-annual changes in 14C concentrations in rice grain. The scenario, however, offered little opportunity for comparing the predictive capabilities of these two types of models because the scenario involved a near-chronic release to the atmosphere. A scenario based on an episodic release and short-term, time-dependent observations is needed to establish the overall confidence in the predictions of environmental 14C models

  2. Dissolved Organic Carbon 14C in Southern Nevada Groundwater and Implications for Groundwater Travel Times

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L. [Nevada University, Reno, NV (United States). Desert Research Institute; Fereday, Wyall [Nevada University, Reno, NV (United States). Desert Research Institute; Thomas, James M [Nevada University, Reno, NV (United States). Desert Research Institute

    2016-08-01

    Dissolved inorganic carbon (DIC) carbon-14 (14C) ages must be corrected for complex chemical and physical reactions and processes that change the amount of 14C in groundwater as it flows from recharge to downgradient areas. Because of these reactions, DIC 14C can produce unrealistically old ages and long groundwater travel times that may, or may not, agree with travel times estimated by other methods. Dissolved organic carbon (DOC) 14C ages are often younger than DIC 14C ages because there are few chemical reactions or physical processes that change the amount of DOC 14C in groundwater. However, there are several issues that create uncertainty in DOC 14C groundwater ages including limited knowledge of the initial (A0) DOC 14C in groundwater recharge and potential changes in DOC composition as water moves through an aquifer. This study examines these issues by quantifying A0 DOC 14C in recharge areas of southern Nevada groundwater flow systems and by evaluating changes in DOC composition as water flows from recharge areas to downgradient areas. The effect of these processes on DOC 14C groundwater ages is evaluated and DOC and DIC 14C ages are then compared along several southern Nevada groundwater flow paths. Twenty-seven groundwater samples were collected from springs and wells in southern Nevada in upgradient, midgradient, and downgradient locations. DOC 14C for upgradient samples ranged from 96 to 120 percent modern carbon (pmc) with an average of 106 pmc, verifying modern DOC 14C ages in recharge areas, which decreases uncertainty in DOC 14C A0 values, groundwater ages, and travel times. The HPLC spectra of groundwater along a flow path in the Spring Mountains show the same general pattern indicating that the DOC compound composition does not change along this flow path

  3. Sampling and monitoring of carbon-14 in gaseous effluents from nuclear facilities

    International Nuclear Information System (INIS)

    This study reviews the possibilities from sampling and monitoring C-14 in gaseous effluents from nuclear facilities. After oxidation of various forms of carbon-14 in the off-gas into CO2 three main processes for trapping are used either separately or in combination. These are sorption, freezing and chemical processes. Absorption in alkaline solutions or solids or molecular sieve adsorption are the most frequently used methods. The main counting methods used are gas proportional counting and liquid scintillation counting

  4. Carbon-14 production compared to oxygen isotope records from Camp Century, Greenland and Devon Island, Canada

    International Nuclear Information System (INIS)

    Carbon-14 production rate variations that are not explainable by geomagnetic changes are thought to be in antiphase with solar activity and as such should be in antiphase with paleotemperature records or proxy temperature histories such as those obtainable from oxygen isotope analyses of ice cores. Oxygen isotope records from Camp Century, Greeland and Devon Island Ice Cap are in phase with each other over thousands of years and in antiphase to the 14C production rate residuals. (Auth.)

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

    Science.gov (United States)

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

    2014-11-25

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

  6. Proportion of biogenic carbon in flue gas by carbon-14 measurement; Biohiili2: Biohiilen mittaus savukaasusta hiili-14-menetelmaellae

    Energy Technology Data Exchange (ETDEWEB)

    Lehtomaeki, J.; Antson, O.; Hongisto, M.; Knuuttila, M.; Roine, J.; Raesaenen, J.; Tormonen, K. [VTT Technical Research Centre of Finland, Espoo (Finland); Jungner, H. [Helsinki Univ. (Finland)

    2007-07-01

    The subject of this project is closely related to EU's emissions trading system and to the current and future monitoring needs therein. The determination of fossil part of emissions originated from various fuels by stack measurements or by laboratory analyses could possibly find users also in other fields outside the ETS (e.g. waste incineration). After the market analysis and preliminary measurements carried out in the previous Biocarbon project this project focused on the development of the sampling method for stack measurements and to the validation of isotope measurements. The results obtained for fossil proportion of the fuel by current methods will be compared to those obtained by isotope measurements. The operation of the sampling system was tested in long period tests in plant conditions. Moreover, the sample preparation methods and isotope measurements were validated by measuring the proportions of biogenic and fossil carbon of known traffic fuel mixtures. The developed service concept can also be utilised as a fraud prevention measure related to the expanding international biofuels-trade. (orig.)

  7. 14.7% efficient mesoscopic perovskite solar cells using single walled carbon nanotubes/carbon composite counter electrodes

    Science.gov (United States)

    Li, Hao; Cao, Kun; Cui, Jin; Liu, Shuangshuang; Qiao, Xianfeng; Shen, Yan; Wang, Mingkui

    2016-03-01

    A single walled carbon nanotube (SWCNT) possesses excellent hole conductivity. This work communicates an investigation of perovskite solar cells using a mesoscopic TiO2/Al2O3 structure as a framework in combination with a certain amount of SWCNT-doped graphite/carbon black counter electrode material. The CH3NH3PbI3-based device achieves a power conversion efficiency of 14.7% under AM 1.5G illumination. Detailed investigations show an increased charge collection in this device compared to that without the SWCNT additive.A single walled carbon nanotube (SWCNT) possesses excellent hole conductivity. This work communicates an investigation of perovskite solar cells using a mesoscopic TiO2/Al2O3 structure as a framework in combination with a certain amount of SWCNT-doped graphite/carbon black counter electrode material. The CH3NH3PbI3-based device achieves a power conversion efficiency of 14.7% under AM 1.5G illumination. Detailed investigations show an increased charge collection in this device compared to that without the SWCNT additive. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07347b

  8. 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

  9. A Brief Review of the Application of 14C in Terrestrial Carbon Cycle Studies

    Energy Technology Data Exchange (ETDEWEB)

    Guilderson, T; Mcfarlane, K

    2009-10-22

    An over-arching goal of the DOE TCP program is to understand the mechanistic controls over the fate, transport, and residence time of carbon in the terrestrial biosphere. Many of the modern process and modeling studies focus on seasonal to interannual variability. However, much of the carbon on the landscape and in soils is in separate reservoirs with turnover times that are multi-decadal to millennial. It is the controls on these longer term pools or reservoirs that is a critical unknown in the face of rising GHGs and climate change and uncertainties of the terrestrial biosphere as a future global sink or source of atmospheric CO{sub 2} [eg., Friedlingstein et al., 2006; Govindasamy et al., 2005; Thompson et al., 2004]. Radiocarbon measurements, in combination with other data, can provide insight into, and constraints on, terrestrial carbon cycling. Radiocarbon (t{sub 1/2} 5730yrs) is produced naturally in the stratosphere when secondary neutrons generated by cosmic rays collide with {sup 14}N atoms [Libby 1946; Arnold and Libby, 1949]. Upon formation, {sup 14}C is rapidly oxidized to CO and then to CO{sub 2}, and is incorporated into the carbon cycle. Due to anthropogenic activities, the amount of {sup 14}C in the atmosphere doubled in the mid/late 1950s and early 1960s from its preindustrial value of {sup 14}C/{sup 12}C ratio of 1.18 x 10{sup -12} [eg., Nydal and Lovseth, 1983]. Following the atmospheric weapons test ban in 1963, the {sup 14}C/{sup 12}C ratio, has decreased due to the net isotopic exchange between the ocean and terrestrial biosphere [eg., Levin and Hessheimer, 2000] and a dilution effect due to the burning of {sup 14}C-free fossil fuel carbon, the 'Suess Effect' [Suess, 1955]. In the carbon cycle literature, radiocarbon measurements are generally reported as {Delta}{sup 14}C, which includes a correction for mass dependent fractionation [Stuiver and Polach, 1977]. In the context of carbon cycle studies radiocarbon measurements can be

  10. Variation of 14C, 137Cs and stable carbon composition in forest soil and its implications

    International Nuclear Information System (INIS)

    In Japan, about 70% of land area is covered by forest. Therefore, forest ecosystem plays a vital role in ultimate fate of radionuclides and carbon cycle in terrestrial environment. Three undisturbed forest soil profiles were collected from Ibaraki Prefecture, Japan. The 137Cs data illustrate that maximum fallout deposition of 137Cs took place around 1964. 14C determination shows that 14C also has peak values in the top 10 cm of the soil profiles ascribed to the highest bomb 14C level in 1960's. The 13C data show that the turnover dynamics of soil organic carbon could be described very well by progressive enrichment values of δ13C. (author)

  11. Photosynthesis and assimilate partitioning characteristics of the coconut palm as observed by carbon-14 labelling

    International Nuclear Information System (INIS)

    A technique was developed on the use of carbon dioxide(carbon-14 labelled) rapid labelling of foliage and to ascertain photosynthesis and partitioning characteristics of labelled assimilate into other parts of the coconut palm. An eight-year-old Tall x Tall young coconut palm growing under field conditions at Bandirippuwa Estate and with six developing bunches , was selected for this study. The labelling was carried out on a bright sunny day and soil was at field capacity. Seventh leaf from the youngest open leaf was used for labelling with 5 mCi of sodium bi carbonate (Carbon-14 labelled). The results revealed that within 24 hours, 60% of the labelled assimilate was partitioned into other parts of the palm and at the end of the seventh day about 18% of the labelled assimilate still remained in the labelled leaf. Among the developing bunches fifth and sixth bunches from the youngest developing bunch received more labelled assimilate than young developing bunches above them. It was revealed that partitioning of assimilate into various ''sinks'' is determined by the developmental stage or activeness of the ''sink''. The proportion of C-14 labelled carbon assimilate, partitioned into developing bunches was substantially low compared to the total amount of labelled carbon fixed by the labelled leaf. Further, it was observed that partitioning of assimilated labelled carbon into the young leaves above, as well as the mature leaves below the labelled leaf. The complex vascular anatomy of the palms could be attributed to this pattern of partitioning of assimilates into upper and lower leaves from the labelled leaf

  12. Factors affecting carbon-14 activity of unsaturated zone CO2 and implications for groundwater dating

    Science.gov (United States)

    Wood, Cameron; Cook, Peter G.; Harrington, Glenn A.; Meredith, Karina; Kipfer, Rolf

    2014-11-01

    Unsaturated zone processes may influence the carbon-14 (14C) activity of infiltrating groundwater and thus introduce error in derived groundwater residence times. However unsaturated zone 14C activities are rarely measured and there is little understanding of how they may vary spatially in a groundwater basin. In this study we measured 14C activity in unsaturated zone gas at five sites with different watertable depths (8.2-31.5 m) in the arid Ti Tree Basin, central Australia. We observed a relatively uniform decrease in 14C activity of unsaturated zone gas with depth at most sites, with variation in unsaturated zone depths leading to variation in 14C activities directly above the watertable at each site (ranging from 54 to 106 percent Modern Carbon (pMC)). Through modelling we show that the profiles are influenced by CO2 production at different depths from sources with different isotopic ratios, including production of ‘modern' CO2 in the root zone and production of ‘old' CO2 above the watertable. Scenario modelling showed that these processes are independent of recharge when recharge is low (0-10 mm y-1) but that higher recharge rates (>100 mm y-1) result in more advective transport of atmospheric CO2 to the watertable. The variation in 14C above the watertable was more sensitive to watertable depth and shallow and deep CO2 production rates. These findings offer insight into how unsaturated zone 14C activities may vary spatially and provide guidance as to when 14C depletion in unsaturated zone CO2 may become important for groundwater dating, particularly in arid settings.

  13. Multiphase Carbon-14 Transport in a Near-Field-Scale Unsaturated Column of Natural Sediments

    Energy Technology Data Exchange (ETDEWEB)

    D. T. Fox; Mitchell A. Plummer; Larry C. Hull; D. Craig Cooper

    2004-03-01

    Wastes buried at the Subsurface Disposal Area (SDA) of the Idaho National Engineering and Environmental Laboratory include activated metals that release radioactive carbon-14 (14C) as they corrode. To better understand 14C phase partitioning and transport in the SDA sediments, we conducted a series of transport experiments using 14C (radio-labeled sodium carbonate) and nonreactive gas (sulfur hexafluoride) and aqueous (bromide and tritiated water) tracers in a large (2.6-m high by 0.9-m diameter) column of sediments similar to those used as cover material at the SDA. We established steady-state unsaturated flow prior to injecting tracers into the column. Tracer migration was monitored using pore-water and pore-gas samples taken from co-located suction lysimeters and gas ports inserted at ~0.3-m intervals along the column’s length. Measurements of 14C discharged from the sediment to the atmosphere (i.e., 14CO2 flux) indicate a positive correlation between CO2 partial pressure (pCO2) in the column and changes in 14CO2 flux. Though 14CO2 diffusion is expected to be independent of pCO2, changes of pCO2 affect pore water chemistry sufficiently to affect aqueous/gas phase 14C partitioning and consequently 14C2 flux. Pore-water and -gas 14C activity measurements provide an average aqueous/gas partitioning ratio, Kag, of 4.5 (±0.3). This value is consistent with that calculated using standard carbonate equilibrium expressions with measured pH, suggesting the ability to estimate Kag from carbonate equilibrium. One year after the 14C injection, the column was cored and solid-phase 14C activity was measured. The average aqueous/solid partition coefficient, Kd, (1.6 L kg-1) was consistent with those derived from small-scale and short-term batch and column experiments using SDA sediments, suggesting that bench-scale measurements are a valid means of estimating aqueous/solid partitioning at the much larger spatial scale considered in these meso-scale experiments. However

  14. Carbon-14 in waste packages for spent fuel in a tuff repository

    International Nuclear Information System (INIS)

    Carbon-14 is produced naturally by cosmic ray neutrons in the upper atmosphere. It is also produced in nuclear reactors, in amounts much smaller than the global inventory. About one-third of this is released directly to the atmosphere, and the other two-thirds remains in the spent fuel. Both the Environmental Protection Agency and the Nuclear Regulatory Commission have established limits on release of the 14C in spent fuel. This is of particular concern for the proposed repository in tuff, because of the unsaturated conditions and the consequent possibility of gaseous transport of 14C as CO2. Existing measurements and calculations of the 14C inventory in spent fuel are reviewed. The physical distribution and chemical forms of the 14C are discussed. Available data on the release of 14C from spent fuel in aqueous solutions and in gaseous environments of air, nitrogen, and helium are reviewed. Projected 14C behavior in a tuff repository is described. It is concluded that 14C release measurements from spent fuel into moist air at temperatures both above and below the in situ boiling point of water as well as detailed transport calculations for the tuff geological environment will be needed to determine whether the 10CFR60 and 40CFR191 requirements can be met. 56 refs., 1 tab

  15. Modelling the Environmental Transfer of Tritium and Carbon-14 to Biota and Man. Report of the Tritium and Carbon-14 Working Group of EMRAS Theme 1

    International Nuclear Information System (INIS)

    Hydrogen and carbon are biologically-regulated, essential elements that are highly mobile in the environment and the human body. As isotopes of these elements, tritium and 14C enter freely into water (in the case of tritium), plants, animals and humans. This complex behaviour means that there are substantial uncertainties in the predictions of models that calculate the transfer of tritium and 14C through the environment. The EMRAS Tritium/C14 Working Group (WG) was set up to establish the confidence that can be placed in the predictions of such models, to recommend improved modelling approaches, and to encourage experimental work leading to the development of data sets for model testing. The activities of the WG focused on the assessment of models for organically bound tritium (OBT) formation and translocation in plants and animals, the area where model uncertainties are largest. Environmental 14C models were also addressed because the dynamics of carbon and OBT are similar. The goals of the WG were achieved primarily through nine test scenarios in which model predictions were compared with observations obtained in laboratory or field studies. Seven of the scenarios involved tritium, covering terrestrial and aquatic ecosystems and steady-state and dynamic conditions. The remaining two scenarios concerned 14C, one addressing steady-state concentrations in plants and the other time-dependent concentrations in animals. The WG also considered one model intercomparison exercise involving the calculation of doses following a hypothetical, short-term release of tritium to the atmosphere in a farming area. Finally, the WG discussed the nature of OBT and proposed a definition to promote common understanding and usage within the international tritium community. The models used by the various participants varied in complexity from simple specific activity approaches to dynamic compartment models and process-oriented models, in which the various transfer processes were

  16. 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...

  17. Algal C-14 and total carbon metabolisms 2. Experimental observations with the diatom Skeletonema costatum

    DEFF Research Database (Denmark)

    Williams, P.J.L.; Robinson, C.; Søndergaard, M.;

    1996-01-01

    of 2-3), C-14 uptake into the particulate plus the dissolved fractions approximated to net photosynthesis. Rate constants derived from the chemically determined changes were used to parameterize models that accounted for the respiration of photosynthetic products and for the recycling of respiratory CO......Three sets of comparisons of net and gross inorganic carbon assimilation and C-14 uptake were made with an axenic culture of Skeletonema costatum. The comparisons showed that in the physiological window studied (10-20% of the intrinsic generation time and gross photosynthesis/respiration ratios......2. The conclusion drawn was that over the time scale studied, the C-14 technique was measuring net photosynthesis, consistent with essentially 100% recycling of respiratory CO2. The study has shown that we now possess the basis to make a rigorous analysis of net, gross CO2 fixation and net C-14...

  18. 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.

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

    Science.gov (United States)

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

    2016-04-01

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

  20. Carbon-14 in neutron-irradiated graphite for graphite-moderated reactors. Joint research

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Kimio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Matsuo, Hideto [Radioactive Waste Management and Nuclear Facility Decommissioning Technology Center, Tokyo (Japan)

    2002-12-01

    The graphite moderated gas cooled reactor operated by the Japan Atomic Power Company was stopped its commercial operation on March 1998, and the decommissioning process has been started. Graphite material is often used as the moderator and the reflector materials in the core of the gas cooled reactor. During the operation, a long life nuclide of {sup 14}C is generated in the graphite by several transmutation reactions. Separation of {sup 14}C isotope and the development of the separation method have been recognized to be critical issues for the decommissioning of the reactor core. To understand the current methodologies for the carbon isotope separation, literature on the subject was surveyed. Also, those on the physical and chemical behavior of {sup 14}C were surveyed. This is because the larger part of the nuclides in the graphite is produced from {sup 14}N by (n,p) reaction, and the location of them in the material tends to be different from those of the other carbon atoms. This report summarizes the result of survey on the open literature about the behavior of {sup 14}C and the separation methods, including the list of the literature on these subjects. (author)

  1. Carbon-14 immobilization via the CO2-Ba(OH)2 hydrate gas-solid reaction

    International Nuclear Information System (INIS)

    Although no restrictions have been placed on the release of carbon-14, it has been identified as a potential health hazard due to the ease in which it may be assimilated into the biosphere. The intent of the Carbon-14 Immobilization Program, funded through the Airborne Waste Program Management Office, is to develop and demonstrate a novel process for restricting off-gas releases of carbon-14 from various nuclear facilities. The process utilizes the CO2-Ba(OH)2 hydrate gas-solid reaction to directly remove and immobilize carbon-14. The reaction product, BaCO3, possesses both the thermal and chemical stability desired for long-term waste disposal. The process is capable of providing decontamination factors in excess of 1000 and reactant utilization of greater than 99% in the treatment of high volumetric, airlike (330 ppM CO2) gas streams. For the treatment of an air-based off-gas stream, the use of packed beds of Ba(OH)2.8H2O flakes to remove CO2 has been demonstrated. However, the operating conditions must be maintained between certain upper and lower limits with respect to the partial pressure of water. If the water vapor pressure in the gas is less than the dissociation vapor pressure of Ba(OH)2.8H2O, the bed will deactivate. If the vapor pressure is considerably greater, pressure drop problems will increase with increasing humidity as the particles curl and degrade. Results have indicated that when operated in the proper regime, the bulk of the increase in pressure drop results from the conversion of Ba(OH)2.8H2O to BaCO3 and not from the hydration of the commercial Ba(OH)2.8H2O (i.e. Ba(OH)2.7.50H2O) to Ba(OH)2.8H2O

  2. Reexposure and advection of C-14-depleted organic carbon from old deposits at the upper continental slope

    OpenAIRE

    Tesi, Tommaso; Goñi, Miguel A.; Langone, Leonardo; Puig, Pere; Canals, Miquel; Nittrouer, Charles A.; Durrieu De Madron, Xavier; Calafat, Antoni; Palanques, Albert; Heussner, Serge; Davies, Maureen H.; Drexler, Tina M.; Fabres, Joan; Miserocchi, Stefano

    2010-01-01

    Outcrops of old strata at the shelf edge resulting from erosive gravity-driven flows have been globally described on continental margins. The reexposure of old strata allows for the reintroduction of aged organic carbon (OC), sequestered in marine sediments for thousands of years, into the modern carbon cycle. This pool of reworked material represents an additional source of C-14-depleted organic carbon supplied to the ocean, in parallel with the weathering of fossil organic carbon delivered ...

  3. 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...

  4. Tumor imaging and targeting potential of an Hsp70-derived 14-mer peptide.

    Directory of Open Access Journals (Sweden)

    Mathias Gehrmann

    Full Text Available BACKGROUND: We have previously used a unique mouse monoclonal antibody cmHsp70.1 to demonstrate the selective presence of a membrane-bound form of Hsp70 (memHsp70 on a variety of leukemia cells and on single cell suspensions derived from solid tumors of different entities, but not on non-transformed cells or cells from corresponding 'healthy' tissue. This antibody can be used to image tumors in vivo and target them for antibody-dependent cellular cytotoxicity. Tumor-specific expression of memHsp70 therefore has the potential to be exploited for theranostic purposes. Given the advantages of peptides as imaging and targeting agents, this study assessed whether a 14-mer tumor penetrating peptide (TPP; TKDNNLLGRFELSG, the sequence of which is derived from the oligomerization domain of Hsp70 which is expressed on the cell surface of tumor cells, can also be used for targeting membrane Hsp70 positive (memHsp70+ tumor cells, in vitro. METHODOLOGY/PRINCIPAL FINDINGS: The specificity of carboxy-fluorescein (CF- labeled TPP (TPP to Hsp70 was proven in an Hsp70 knockout mammary tumor cell system. TPP specifically binds to different memHsp70+ mouse and human tumor cell lines and is rapidly taken up via endosomes. Two to four-fold higher levels of CF-labeled TPP were detected in MCF7 (82% memHsp70+ and MDA-MB-231 (75% memHsp70+ cells compared to T47D cells (29% memHsp70+ that exhibit a lower Hsp70 membrane positivity. After 90 min incubation, TPP co-localized with mitochondrial membranes in memHsp70+ tumors. Although there was no evidence that any given vesicle population was specifically localized, fluorophore-labeled cmHsp70.1 antibody and TPP preferentially accumulated in the proximity of the adherent surface of cultured cells. These findings suggest a potential association between membrane Hsp70 expression and cytoskeletal elements that are involved in adherence, the establishment of intercellular synapses and/or membrane reorganization. CONCLUSIONS

  5. 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.

  6. Modelling of dead carbon fraction in speleothems: a step towards reliable speleothem 14C-chronologies

    Science.gov (United States)

    Lechleitner, Franziska A.; Jamieson, Robert A.; McIntyre, Cameron; Baldini, Lisa M.; Baldini, James U. L.; Eglinton, Timothy I.

    2015-04-01

    Over the past two decades, speleothems have become one of the most versatile and promising archives for the study of past continental climate. Very precise absolute dating is often possible using the U-Th method, resulting in paleoclimate records of exceptional resolution and accuracy. However, not all speleothems are amenable to this dating method for a variety of reasons (e.g. low U concentrations, high detrital Th etc). This has lead researchers to exclude many otherwise suitable speleothems and cave sites from further investigation. 14C-dating of speleothems has so far not been applicable, due to the 'dead carbon' problem. As drip water percolates through the karst, dissolving CaCO3, a variable amount of 14C-dead carbon is added to the solution. This results in a temporally variable and site-specific reservoir effect, ultimately undermining the development of speleothem 14C -chronologies. However, a number of recent studies have shown a clear link between karst hydrology and associated proxies (e.g., Mg/Ca and δ13C) and this 'dead carbon fraction' (DCF). We take advantage of this relationship to model DCF and its changes using Mg/Ca, δ13C and 14C data from published speleothem records. Using one record for calibration purposes, we build a transfer function for the DCF in relation to δ13C and Mg/Ca, which we then apply to other 14C records. Initial model results are promising; we are able to reconstruct general long-term average DCF within uncertainties of the calculated DCF from the U-Th chronology. Large shifts in DCF related to hydrology are also often detected. In a second step, we apply the model to a speleothem from southern Poland, which so far could not be dated, due to very low U-concentrations. To construct a 14C chronology, the stalagmite was sampled at 5 mm intervals. CaCO3 powders were graphitized and measured by Accelerator Mass Spectrometry (MICADAS) at ETH Zurich. Additional high-resolution (0.1 mm/sample) 14C measurements were performed on

  7. 14C Activity and Global Carbon Cycle Changes over the Past 50,000 Years

    Science.gov (United States)

    Hughen, K.; Lehman, S.; Southon, J.; Overpeck, J.; Marchal, O.; Herring, C.; Turnbull, J.

    2004-01-01

    A series of 14C measurements in Ocean Drilling Program cores from the tropical Cariaco Basin, which have been correlated to the annual-layer counted chronology for the Greenland Ice Sheet Project 2 (GISP2) ice core, provides a high-resolution calibration of the radiocarbon time scale back to 50,000 years before the present. Independent radiometric dating of events correlated to GISP2 suggests that the calibration is accurate. Reconstructed 14C activities varied substantially during the last glacial period, including sharp peaks synchronous with the Laschamp and Mono Lake geomagnetic field intensity minimal and cosmogenic nuclide peaks in ice cores and marine sediments. Simulations with a geochemical box model suggest that much of the variability can be explained by geomagnetically modulated changes in 14C production rate together with plausible changes in deep-ocean ventilation and the global carbon cycle during glaciation.

  8. Source terms; isolation and radiological consequences of carbon-14 waste in the Swedish SFR repository

    International Nuclear Information System (INIS)

    The source term, isolation capacity, and long-term radiological exposure of 14C from the Swedish underground repository for low and intermediate level waste (SFR) is assessed. The prospective amount of 14C in the repository is assumed to be 5 TBq. Spent ion exchange resins will be the dominant source of 14C. The pore water in the concrete repository is expected to maintain a pH of >10.5 for a period of at least 106 y. The cement matrix of the repository will retain most of the 14CO32- initially present. Bacterial production of CO2 and CH4 from degradation of ion-exchange resins and bitumen may contribute to 14C release to the biosphere. However, CH4 contributes only to a small extent to the overall carbon loss from freshwater ecosystems. The individual doses to local and regional individuals peaked with 5x10-3 and regional individuals peaked with 5x10-3 and 8x10-4 μSv y-1 respectively at about 2.4x104 years. A total leakage of 8.4 GBq of 14C from the repository will cause a total collective dose commitment of 1.1 manSv or 130 manSv TBq-1. (authors)

  9. Analytical Validation of Accelerator Mass Spectrometry for Pharmaceutical Development: the Measurement of Carbon-14 Isotope Ratio.

    Energy Technology Data Exchange (ETDEWEB)

    Keck, B D; Ognibene, T; Vogel, J S

    2010-02-05

    Accelerator mass spectrometry (AMS) is an isotope based measurement technology that utilizes carbon-14 labeled compounds in the pharmaceutical development process to measure compounds at very low concentrations, empowers microdosing as an investigational tool, and extends the utility of {sup 14}C labeled compounds to dramatically lower levels. It is a form of isotope ratio mass spectrometry that can provide either measurements of total compound equivalents or, when coupled to separation technology such as chromatography, quantitation of specific compounds. The properties of AMS as a measurement technique are investigated here, and the parameters of method validation are shown. AMS, independent of any separation technique to which it may be coupled, is shown to be accurate, linear, precise, and robust. As the sensitivity and universality of AMS is constantly being explored and expanded, this work underpins many areas of pharmaceutical development including drug metabolism as well as absorption, distribution and excretion of pharmaceutical compounds as a fundamental step in drug development. The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of {sup 14}C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the {sup 14}C label), stable across samples storage conditions for at least one year, linear over 4 orders of magnitude with an analytical range from one tenth Modern to at least 2000 Modern (instrument specific). Further, accuracy was excellent between 1 and 3 percent while precision expressed as coefficient of variation is between 1 and 6% determined primarily by radiocarbon content and the time spent analyzing a sample. Sensitivity, expressed as LOD and LLOQ was 1 and 10 attomoles of carbon-14 (which can be expressed as compound equivalents) and for a typical small molecule labeled at 10% incorporated with {sup 14}C corresponds to 30 fg

  10. Proportion of biogenic carbon in flue gas by carbon-14 measurement - part 2; Biohiili 2

    Energy Technology Data Exchange (ETDEWEB)

    Lehtomaeki, J.; Antson, O.; Hongisto, M. (VTT Technical Research Centre of Finland, Espoo (Finland)) (and others)

    2009-07-01

    The subject of this project is closely related to EU's emissions trading system and to the current and future monitoring needs therein. The determination of fossil part of emissions originated from various fuels by stack measurements or by laboratory analyses could possibly find users also in other fields outside the ETS - Emission Trading Scheme (e.g. waste incineration). After the market analysis and preliminary measurements carried out in the previous Biocarbon project this project focused on the development of the sampling method for stack measurements and to the validation of isotope measurements. The results obtained for fossil proportion of the fuel by current methods will be compared to those obtained by isotope measurements. The operation of the sampling system was tested in long period tests in plant conditions. Moreover, the sample preparation methods and isotope measurements were validated by measuring the proportions of biogenic and fossil carbon of known traffic fuel mixtures. The developed method can also be utilised as a fraud prevention measure related to the expanding international biofuels-trade. (orig.)

  11. Synthesis of a polycyclic aromatic hydrocarbon marked with carbon-14: (b, d e f) dibenzo-chrysene {sup 14}C-7,14; Synthese d'un hydrocarbure aromatique polycyclique marque au carbone 14: le dibenzo (b, d e f) chrysene {sup 14}C-7,14

    Energy Technology Data Exchange (ETDEWEB)

    Chatelain, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    (b, d e f) dibenzo-chrysene C-7,14 has been synthesized from radioactive carbon dioxide and the organic magnesium compound derived from 1,5 dibromo naphthalene. The product has been purified by a very precise series of fractionated chromatographs on alumina having a chromatographic activity. This has necessitated the development of a special technique. (author) [French] Le dibenzo (b, d e f) chrysene 14C-7,14 a ete synthetise au depart de gaz carbonique radioactif et de bis-organomagnesien derive du dibromo-1,5 naphtalene. Le produit a ete purifie par une serie de chromatographies fractionnees sur alumine d'activite chromatographique tres precise. Ceci a fait l'objet d'une mise au point de technique. (auteur)

  12. Targeting Ergosterol biosynthesis in Leishmania donovani: essentiality of sterol 14 alpha-demethylase.

    Science.gov (United States)

    McCall, Laura-Isobel; El Aroussi, Amale; Choi, Jun Yong; Vieira, Debora F; De Muylder, Geraldine; Johnston, Jonathan B; Chen, Steven; Kellar, Danielle; Siqueira-Neto, Jair L; Roush, William R; Podust, Larissa M; McKerrow, James H

    2015-03-01

    Leishmania protozoan parasites (Trypanosomatidae family) are the causative agents of cutaneous, mucocutaneous and visceral leishmaniasis worldwide. While these diseases are associated with significant morbidity and mortality, there are few adequate treatments available. Sterol 14alpha-demethylase (CYP51) in the parasite sterol biosynthesis pathway has been the focus of considerable interest as a novel drug target in Leishmania. However, its essentiality in Leishmania donovani has yet to be determined. Here, we use a dual biological and pharmacological approach to demonstrate that CYP51 is indispensable in L. donovani. We show via a facilitated knockout approach that chromosomal CYP51 genes can only be knocked out in the presence of episomal complementation and that this episome cannot be lost from the parasite even under negative selection. In addition, we treated wild-type L. donovani and CYP51-deficient strains with 4-aminopyridyl-based inhibitors designed specifically for Trypanosoma cruzi CYP51. While potency was lower than in T. cruzi, these inhibitors had increased efficacy in parasites lacking a CYP51 allele compared to complemented parasites, indicating inhibition of parasite growth via a CYP51-specific mechanism and confirming essentiality of CYP51 in L. donovani. Overall, these results provide support for further development of CYP51 inhibitors for the treatment of visceral leishmaniasis. PMID:25768284

  13. Targeting Ergosterol biosynthesis in Leishmania donovani: essentiality of sterol 14 alpha-demethylase.

    Directory of Open Access Journals (Sweden)

    Laura-Isobel McCall

    2015-03-01

    Full Text Available Leishmania protozoan parasites (Trypanosomatidae family are the causative agents of cutaneous, mucocutaneous and visceral leishmaniasis worldwide. While these diseases are associated with significant morbidity and mortality, there are few adequate treatments available. Sterol 14alpha-demethylase (CYP51 in the parasite sterol biosynthesis pathway has been the focus of considerable interest as a novel drug target in Leishmania. However, its essentiality in Leishmania donovani has yet to be determined. Here, we use a dual biological and pharmacological approach to demonstrate that CYP51 is indispensable in L. donovani. We show via a facilitated knockout approach that chromosomal CYP51 genes can only be knocked out in the presence of episomal complementation and that this episome cannot be lost from the parasite even under negative selection. In addition, we treated wild-type L. donovani and CYP51-deficient strains with 4-aminopyridyl-based inhibitors designed specifically for Trypanosoma cruzi CYP51. While potency was lower than in T. cruzi, these inhibitors had increased efficacy in parasites lacking a CYP51 allele compared to complemented parasites, indicating inhibition of parasite growth via a CYP51-specific mechanism and confirming essentiality of CYP51 in L. donovani. Overall, these results provide support for further development of CYP51 inhibitors for the treatment of visceral leishmaniasis.

  14. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  16. Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic : 14C characteristics of sedimentary carbon components and their environmental controls

    NARCIS (Netherlands)

    Feng, Xiaojuan; Gustafsson, Örjan; Holmes, R. Max; Vonk, Jorien E.; Van Dongen, Bart E.; Semiletov, Igor P.; Dudarev, Oleg V.; Yunker, Mark B.; Macdonald, Robie W.; Wacker, Lukas; Montluçon, Daniel B.; Eglinton, Timothy I.

    2015-01-01

    Distinguishing the sources, ages, and fate of various terrestrial organic carbon (OC) pools mobilized from heterogeneous Arctic landscapes is key to assessing climatic impacts on the fluvial release of carbon from permafrost. Through molecular 14C measurements, including novel analyses of suberin- a

  17. Validation test for carbon-14 migration and accumulation in a Canadian shield lake

    International Nuclear Information System (INIS)

    This particular BIOMOVS II Technical Report is concerned with modelling the transfer of C-14 through the aquatic food chain following release to a Canadian shield lake. Model performance has been tested against field data supplied by Atomic Energy of Canada Limited. Carbon-14 was added in 1978 to the epilimnion of a small Canadian Shield lake to investigate primary production and carbon dynamics. Data from this experiment were used within BIOMOVS II to provide a validation test, which involved modelling the fate of the C-14 added to the lake. The nature of the spike and the subsequent monitoring allowed the investigation of both short-term processes relevant to evaluation of the impacts of accidental releases as well as longer-term processes relevant to routine release and to solid waste disposal. Four models participated in the scenario: 1) a simple mass balance model of a lake (AECL, Whiteshell Laboratories, Canada); 2) a relatively complex deterministic dynamic compartment model (QuantiSci Ltd.,UK); 3) a complex deterministic model (Studsvik Model A) and a more complex probabilistic model (Studsvik Model B; Studsvik Eco and Safety AB, Sweden). Endpoints were C-14 concentrations in water, sediment and whitefish over a thirteen year period. Each model produced reasonable predictions when compared to the observed data and when uncertainty is taken into consideration. About 0.2 to 0.4% of the initial C-14 inventory to the lakes remained in the water at the end of the study, because of internal recycling of C-14 from sediments. The simple AECL model did not account for this internal recycling of C-14 and, in this respect, its predictions were not as realistic as those of the QuantiSci and Studsvik models for concentrations in water. However, the AECL model predictions for the C-14 inventory remaining in lake sediment were closest to the observed values. Overall, Studsvik Model B was the most accurate in simulating C-14 concentrations in water and in whitefish, but

  18. 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 ...

  19. Utilization of Tritium and Carbon-14 in Studies of Isotope Effects

    International Nuclear Information System (INIS)

    The utility of tritium in organic research has been augmented by the development of a simple method for determining C14 and tritium in the same sample. The non-volatile, radioactive material, in a film that is 'infinitely thick' to tritium radiation, is counted in a windowless, gas-fiow proportional counter; the film is then re-counted when covered with a screen that stops all radiation from tritium but allows a fraction of that from C14 to pass. By introduction of one isotope at a point removed from the reaction centre, an isotope effect for the other can be determined from changes in the tritium-C14 ratio in the reactant and/or products as the reaction proceeds. Carriers of reactant, products or derivatives can be added at any point to facilitate isolation, because the analytical method depends primarily on the tritium-C14 ratio. Methods for utilizing the double-label technique will be illustrated by a study of isotope effects in the oxidation of the penultimate carbon of certain labelled polyols with Acetobacter suboxydans. Six D-mannitols position-labelled either with C14 or with tritium at C1, C2 or C3 were prepared. For these, isotope effects (k*/k) of 0.93, 0.23, and 0.71, respectively, were found with C14 at C2, tritium at C2, and tritium at C3; no detectable isotope effects were found for the remaining Dmannitols. In the oxidation of position-labelled D-glucitols, an isotope effect of 0.24 was found for tritium at C5; no detectable effect was found for either C14 or tritium at C1. The techniques are suitable for studying a variety of chemical and biological reactions. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-10-15

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

  1. Prise en compte du carbone 14 dans le modèle PASIM

    OpenAIRE

    Duclos, Etienne

    2010-01-01

    J'ai effectué mon stage de fin d'étude d'ingénieur ISIMA au sein de l'Institut National de la Recherche Agronomique (INRA), dans l'Unité de Recherche sur l'Ecosystème Prairial (UREP). Mon stage a été effectué en collaboration avec l'Institut de Radioprotection et de Sûreté Nucléaire (IRSN). J'ai été chargé d'ajouter la gestion du carbone 14 au sein de PaSim, modèle de simulation de prairie gérant déjà les flux de carbone et d'azote. Il m'a donc fallu faire la distinction, au...

  2. 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.)

  3. 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.

  4. 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.

  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. 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.

  7. Protein kinase C gamma mutations in spinocerebellar ataxia 14 increase kinase activity and alter membrane targeting

    NARCIS (Netherlands)

    Verbeek, D. S.; Knight, M. A.; Harmison, G. G.; Fischbeck, K. H.; Howell, B. W.

    2005-01-01

    The protein kinase C gamma (PKCgamma) gene is mutated in spinocerebellar ataxia type 14 (SCA14). In this study, we investigated the effects of two SCA14 missense mutations, G118D and C150F, on PKCgamma function. We found that these mutations increase the intrinsic activity of PKCgamma. Direct visual

  8. 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

  9. Synthesis of {delta}-aminolevulic acid. Application to the introduction of carbon-14 and of tritium; Syntheses de l'acide {delta} aminolevulique. Application a l'introduction de carbone 14 et de tritium

    Energy Technology Data Exchange (ETDEWEB)

    Loheac, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-06-01

    Several new syntheses of {delta} aminolevulic acid ({delta} A.L.A.) have been studied. {sup 14}C-4 {delta} - aminolevulic acid has been obtained from {sup 14}C allylacetic carboxylic acid with a yield of 30 per cent with respect to barium carbonate and with a specific activity of 32 mCi/mM. The {sup 14}C-1 or {sup 14}C-2 {delta}-A.L.A. has been prepared from the {sup 14}C-1 or {sup 14}C-2 acetate with a yield of 55 per cent with respect to the acetate. Finally the tritiated {delta}-A.L.A. has been obtained for the first time by tritiation of ethyl phthalimidodehydrolevulate. (author) [French] Plusieurs syntheses nouvelles de l'acide {delta}-aminolevulique ont ete etudiees. L'acide {delta}-aminolevulique {sup 14}C-4 a ete obtenu a partir d'acide allylacetique carboxylique {sup 14}C, avec un rendement global de 30 pour cent par rapport au carbonate de baryum a une activite specifique de 32 mCi/M. Le {delta}-A.A.L. {sup 14}C-1 ou {sup 14}C-2 a ete obtenu a partir d'acetate {sup 14}C-1 ou {sup 14}C-2 avec un rendement de 55 pour cent par rapport a l'acetate. Enfin le {delta}-A.A.L. tritie a ete obtenu pour la premiere fois par tritiation du phtalimidodehydrolevulate d'ethyle. (auteur)

  10. Tritium- and carbon-14-contents of wines of different vintage from the northern and southern hemisphere

    International Nuclear Information System (INIS)

    The carbon-14 and tritium radioactivity contents of up to 19 vintages of German and Southafrican wines were compared. A similar large dependence of the 14C- and of the 3H-activity in the German wine on the nuclear weapon tests of the years 1962/63 was found out. The radioactivity level is also 1977/78 still essentially higher than before 1950. The Southafrican wines have been influenced considerably less by nuclear explosions. The highest 3H-values were found in the vintage 1963 of the German wine with 5910 pCi/litre and in the vintage 1964 of the Southafrican wine with 510 pCi/litre. (orig.)

  11. Analysis and Characterization of Organic Carbon in Early Holocene Wetland Paleosols using Ramped Pyrolysis 14C and Biomarkers

    Science.gov (United States)

    Vetter, L.; Schreiner, K. M.; Fernandez, A.; Rosenheim, B. E.; Tornqvist, T. E.

    2014-12-01

    Radiocarbon analyses are a key tool for quantifying the dynamics of carbon cycling and storage in both modern soils and Quaternary paleosols. Frequently, bulk 14C dates of paleosol organic carbon provide ages older than the time of soil burial, and 14C dates of geochemical fractions such as alkali and acid extracts (operationally defined as humic acids) can provide anomalously old ages when compared to coeval plant macrofossil dates. Ramped pyrolysis radiocarbon analysis of sedimentary organic material has been employed as a tool for investigating 14C age spectra in sediments with multiple organic carbon sources. Here we combine ramped pyrolysis 14C analysis and biomarker analysis (lignin-phenols and other cupric oxide products) to provide information on the source and diagenetic state of the paleosol organic carbon. We apply these techniques to immature early Holocene brackish wetland entisols from three sediment cores in southeastern Louisiana, along with overlying basal peats. Surprisingly, we find narrow 14C age spectra across all thermal aliquots from both paleosols and peats. The weighted bulk 14C ages from paleosols and overlying peats are within analytical error, and are comparable to independently analyzed 14C AMS dates from charcoal fragments and other plant macrofossils from each peat bed. Our results suggest high turnover rates of carbon in soils relative to input of exogenous carbon sources. These data raise broader questions about processes within the active soil and during pedogenesis and burial of paleosols that can effectively homogenize radiocarbon content in soils across the thermochemical spectrum. The concurrence of paleosol and peat 14C ages also suggests that, in the absence of peats with identifiable plant macrofossils, ramped pyrolysis 14C analyses of paleosols may be used to provide ages for sea-level indicators.

  12. Mountain scale modeling of transient, coupled gas flow, heat transfer and carbon-14 migration

    International Nuclear Information System (INIS)

    We simulate mountain-scale coupled heat transfer and gas flow at Yucca Mountain. A coupled rock-gas flow and heat transfer model, TGIF2, is used to simulate mountain-scale two-dimensional transient heat transfer and gas flow. The model is first verified against an analytical solution for the problem of an infinite horizontal layer of fluid heated from below. Our numerical results match very well with the analytical solution. Then, we obtain transient temperature and gas flow distributions inside the mountain. These distributions are used by a transient semianalytical particle tracker to obtain carbon-14 travel times for particles starting at different locations within the repository. Assuming that the repository is filled with 30-year-old waste at an initial areal power density of 57 kw/acre, we find that repository temperatures remain above 60 degrees C for more than 10,000 years. Carbon-14 travel times to the surface are mostly less than 1000 years, for particles starting at any time within the first 10,000 years

  13. 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.

  14. 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.

  15. 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.

  16. Synthesis, Characterization, and Biodegradation Studies of Poly(1,4-cyclohexanedimethylene-adipate-carbonates

    Directory of Open Access Journals (Sweden)

    Ajay S. Chandure

    2014-01-01

    Full Text Available Aliphatic/alicyclic poly(1,4-cyclohexanedimethylene-adipate-carbonates (PCACs were synthesized by a transesterification from 1,4-cyclohexamethylendimethanol (1,4-CHDM, adipic acid (AA, diethyl carbonate (DEC, and titanium butoxide Ti(OBu4 as a transesterification catalyst. The synthesized PCACs were characterized by the Fourier transform infrared (FTIR, X-ray diffraction analysis (XRD, solubility, solution viscosity, gel permeation chromatography (GPC, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, and scanning electron microscope (SEM for their structural, physical, thermal, and morphological investigation. The structure of synthesized PCACs was confirmed by FTIR. All TGA curves of PCACs shows 10% weight loss above 270°C, and they reveal good thermal stability. Biodegradability of PCACs was investigated by hydrolytic degradation at (pH 7.2 and 11.5, enzymatic degradation using Rhizopus delemar lips at 37°C in phosphate buffer solution (PBS, and soil burial degradation at 30°C. The hydrolytic degradation shows the greater rate of weight loss in PBS at pH-11.5 than pH-7.2. The hydrolytic and soil burial degradation shows faster rate of weight loss as compared to enzymatic degradation. Biodegradation rate of PCACs follows the order: PCAC-20 > PCAC-40 > PCAC-60. SEM images show that degradation occurred all over the film surface, creating holes and cracks. These biodegradable PCACs may be able to replace conventional polymer in the fabrication of packaging film in near future.

  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. Sterol 14α-demethylase as a potential target for antitrypanosomal therapy: enzyme inhibition and parasite cell growth

    OpenAIRE

    Lepesheva, Galina I.; Ott, Robert D.; Hargrove, Tatiana Y.; Kleshchenko, Yuliya Y.; Schuster, Inge; Nes, W. David; Hill, George C.; Villalta, Fernando; Waterman, Michael R.

    2007-01-01

    Sterol 14α-demethylases (CYP51) serve as primary targets for antifungal drugs and specific inhibition of CYP51s in protozoan parasites Trypanosoma brucei (TB) and Trypanosoma cruzi (TC) might provide an effective treatment strategy for human trypanosomiases. Primary inhibitor selection is based initially on the cytochrome P450 spectral response to ligand binding. Ligands which demonstrate strongest binding parameters were examined as inhibitors of reconstituted TB and TC CYP51 activity in vit...

  19. Overexpression of the 14α-Demethylase Target Gene (CYP51) Mediates Fungicide Resistance in Blumeriella jaapii

    OpenAIRE

    Ma, Zhonghua; Proffer, Tyre J.; Jacobs, Janette L.; Sundin, George W.

    2006-01-01

    Sterol demethylation inhibitor (DMI) fungicides are widely used to control fungi pathogenic to humans and plants. Resistance to DMIs is mediated either through alterations in the structure of the target enzyme CYP51 (encoding 14α-demethylase), through increased expression of the CYP51 gene, or through increased expression of efflux pumps. We found that CYP51 expression in DMI-resistant (DMIR) isolates of the cherry leaf spot pathogen Blumeriella jaapii was increased 5- to 12-fold compared to ...

  20. TWEAK/Fn14 axis: a promising target for the treatment of cardiovascular diseases.

    Directory of Open Access Journals (Sweden)

    Luis Miguel Blanco-Colio

    2014-01-01

    Full Text Available Cardiovascular diseases (CVD are the first cause of mortality in Western countries. CVD include several pathologies such as coronary heart disease, stroke or cerebrovascular accident, congestive heart failure, peripheral arterial disease and aortic aneurysm, among others. Interaction between members of the tumor necrosis factor (TNF superfamily and their receptors elicits several biological actions that could participate in CVD. Tumor necrosis factor-like weak inducer of apoptosis (TWEAK and its functional receptor, fibroblast growth factor-inducible molecule 14 (Fn14, are two proteins belonging to the TNF superfamily that activate NF-κB by both canonical and non-canonical pathways and regulate several cell functions such as proliferation, migration, differentiation, cell death, inflammation, and angiogenesis. TWEAK/Fn14 axis plays a beneficial role in tissue repair after acute injury. However, persistent TWEAK/Fn14 activation mediated by blocking experiments or overexpression experiments in animal models has shown an important role of this axis in the pathological remodeling underlying CVD. In this review, we summarize the role of TWEAK/Fn14 pathway in the development of CVD, focusing on atherosclerosis and stroke and the molecular mechanisms by which TWEAK/Fn14 interaction participates in these pathologies. We also review the role of the soluble form of TWEAK as a biomarker for the diagnosis and prognosis of CVD. Finally, we highlight the results obtained with other members of the TNF superfamily that also activate canonical and non-canonical NF-κB pathway.

  1. 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.

  2. 14CO2-assimilation, translocation of 14C, and 14C-carbonate uptake in different organs of spring barley plants in relation to adult-plant resistance to powdery mildew

    International Nuclear Information System (INIS)

    The cultivar Peruvian of spring barley, which is susceptible at all growth stages, and Asse, which exhibits adult-plant resistance to powdery mildew, were compared in 14CO2 assimilation, distribution of 14C, and 14C-carbonate uptake in different organs of healthy and infected plants. The reduction of 14CO2 assimilation in infected plants at the first and fourth leaf stages was greater in Peruvian than in Asse. In Peruvian, the 14C which was fixed by the infected third leaf of plants with mildew on the lower 3 leaves remained in the third leaves with very little translocation to other parts of the plant. Infection of the lower three leaves at the fourth leaf stage reduced 14CO2 assimilation in noninfected fourth leaves of Asse less than that of Peruvian, but the flow of 14C from the healthy fourth leaves into other plant parts such as leaf sheaths was markedly stimulated in Peruvian compared to Asse. Infection also reduced the uptake of 14C-carbonate by seedling roots, the reduction being greater in Peruvian than Asse. A greater proportion of the 14C absorbed by roots of Asse was translocated to the infected leaves than that of Peruvian. It was concluded that powdery mildew disrupted the normal pattern of photosynthesis and translocation of metabolites in a susceptible cultivar more markedly than in an adult-plant-resistant cultivar of spring barley. (author)

  3. 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.

  4. 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

  5. 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

  6. Introducing the global carbon cycle to middle school students with a 14C research project

    Science.gov (United States)

    Brodman Larson, L.; Phillips, C. L.; LaFranchi, B. W.

    2012-12-01

    Global Climate Change (GCC) is currently not part of the California Science Standards for 7th grade. Required course elements, however, such as the carbon cycle, photosynthesis, and cellular respiration could be linked to global climate change. Here we present a lesson plan developed in collaboration with scientists from Lawrence Livermore National Laboratory, to involve 7th grade students in monitoring of fossil fuel emissions in the Richmond/San Pablo area of California. -The lesson plan is a Greenhouse Gas/Global Climate Change Unit, with an embedded research project in which students will collect plant samples from various locals for analysis of 14C, to determine if there is a correlation between location and how much CO2 is coming from fossil fuel combustion. Main learning objectives are for students to: 1) understand how fossil fuel emissions impact the global carbon cycle, 2) understand how scientists estimate fossil CO2 emissions, and 3) engage in hypothesis development and testing. This project also engages students in active science learning and helps to develop responsibility, two key factors for adolescentsWe expect to see a correlation between proximity to freeways and levels of fossil fuel emissions. This unit will introduce important GCC concepts to students at a younger age, and increase their knowledge about fossil fuel emissions in their local environment, as well as the regional and global impacts of fossil emissions.

  7. 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.

  8. 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.

  9. In vivo uptake of carbon-14-colchicine for identification of tumor multidrug resistance

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, B.M.; Rosa, E.; Biedler, J.L. [Nuclear Medicine Research Lab., New York, NY (United States)] [and others

    1994-07-01

    A major limitation in the treatment of cancer with natural product chemotherapeutic agents is the development of multidrug resistance (MDR). Multidrug resistance is attributed to enhanced expression of the multidrug resistance gene MDR1. Colchicine (CHC) is known to be one of the MDR drugs. The authors have previously demonstrated that it is possible to distinguish multidrug resistant tumors from the multidrug-sensitive tumors in vivo on the basis of tritium ({sup 3}H) uptake following injection of {sup 3}H-CHC. The present studies were carried out in xenografted animals using {sup 14}C-CHC which may be more indicative of {sup 11}C-labeled CHC distribution with regard to circulating metabolites, since metabolic processes following injection of (ring C, methoxy-{sup 11}C)-CHC may produce significant amounts of circulating 1l-carbon fragments (i.e., methanol and/or formaldehyde). Experiments were carried out at a dose of 2 mg/kg. Activity concentration per injected dose was approximately twice as great in sensitive as in resistant tumors (p < 0.05) at 60 min following intravenous injection of {sup 14}C-CHC. About 75% of total activity was CHC in the sensitive tumors. The findings are further confirmed by the quantitative autoradiographic evaluation of resistant and sensitive tumors. These studies confirm our previous observations that it is possible to noninvasively distinguish multidrug-resistant tumors from sensitive tumors in vivo based on uptake of an injected MDR drug using a{sup 14}C-labeled CHC at the same position and of comparable specific activity to a {sup 11}C-CHC tracer used for PET imaging. 16 refs., 5 figs., 2 tabs.

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

    Science.gov (United States)

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

    2015-05-30

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

  11. 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

  12. Keratin 23, a novel DPC4/Smad4 target gene which binds 14-3-3ε

    Directory of Open Access Journals (Sweden)

    Schmiegel Wolff

    2011-04-01

    Full Text Available Abstract Background Inactivating mutations of SMAD4 are frequent in metastatic colorectal carcinomas. In previous analyses, we were able to show that restoration of Smad4 expression in Smad4-deficient SW480 human colon carcinoma cells was adequate to suppress tumorigenicity and invasive potential, whereas in vitro cell growth was not affected. Using this cellular model system, we searched for new Smad4 targets comparing nuclear subproteomes derived from Smad4 re-expressing and Smad4 negative SW480 cells. Methods High resolution two-dimensional (2D gel electrophoresis was applied to identify novel Smad4 targets in the nuclear subproteome of Smad4 re-expressing SW480 cells. The identified candidate protein Keratin 23 was further characterized by tandem affinity purification. Immunoprecipitation, subfractionation and immunolocalization studies in combination with RNAi were used to validate the Keratin 23-14-3-3ε interaction. Results We identified keratins 8 and 18, heat shock proteins 60 and 70, plectin 1, as well as 14-3-3ε and γ as novel proteins present in the KRT23-interacting complex. Co-immunoprecipitation and subfractionation analyses as well as immunolocalization studies in our Smad4-SW480 model cells provided further evidence that KRT23 associates with 14-3-3ε and that Smad4 dependent KRT23 up-regulation induces a shift of the 14-3-3ε protein from a nuclear to a cytoplasmic localization. Conclusion Based on our findings we propose a new regulatory circuitry involving Smad4 dependent up-regulation of KRT23 (directly or indirectly which in turn modulates the interaction between KRT23 and 14-3-3ε leading to a cytoplasmic sequestration of 14-3-3ε. This cytoplasmic KRT23-14-3-3 interaction may alter the functional status of the well described 14-3-3 scaffold protein, known to regulate key cellular processes, such as signal transduction, cell cycle control, and apoptosis and may thus be a previously unappreciated facet of the Smad4 tumor

  13. 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

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

    Science.gov (United States)

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

    1993-12-01

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

  15. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  17. BI-14GENOMIC PROFILING OF A PREDICTIVE SIGNATURE FOR MET-TARGETED THERAPY IN GLIOBLASTOMA

    OpenAIRE

    Johnson, Jennifer; Ascierto, Maria Libera; Newsome, David; Mittal, Sandeep; Kang, Liang; Briggs, Michael; Tanner, Kirk; Michael E. Berens; Marincola, Francesco M.; Vande Woude, George F.; Xie, Qian

    2014-01-01

    The success of molecular targeted therapy against cancer depends on discovering the tumor driver genes and the molecular determinants that control the pathway activity. Glioblastoma (GBM) is one of the most devastating cancers due to its highly infiltrating nature, and MET pathway activation is a major cause of invasion in both primary and recurrent tumors. Because MET inhibitors are in clinical trials against GBM, there may be clinical utility from developing more effective patient enrollmen...

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

    Science.gov (United States)

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

    2016-01-01

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

  19. 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.

  20. Diffusion-type model of the global carbon cycle for the estimation of dose to the world population from releases of carbon-14 to the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Killough, G.G.

    1977-05-01

    A nonlinear dynamic model of the exchange of carbon among the atmosphere, terrestrial biosphere, and ocean is described and applied to estimating the radiation dose to the world's population from the release of /sup 14/C to the atmosphere from the nuclear power industry. A computer implementation of the model, written in the IBM Continuous System Modeling Program III (CSMP III) simulation language, is presented. The model treats the ocean as a diffusive medium with respect to vertical transport of carbon, and the nonlinear variation of CO/sub 2/ partial pressure with the total inorganic carbon concentration in surface waters is taken into account in calculating the transfer rate from ocean to atmosphere. Transfers between the atmosphere and terrestrial biosphere are represented by nonlinear equations which consider CO/sub 2/ fertilization and impose a constraint on the ultimate total carbon mass in the biosphere.

  1. Correction of human phospholamban R14del mutation associated with cardiomyopathy using targeted nucleases and combination therapy.

    Science.gov (United States)

    Karakikes, Ioannis; Stillitano, Francesca; Nonnenmacher, Mathieu; Tzimas, Christos; Sanoudou, Despina; Termglinchan, Vittavat; Kong, Chi-Wing; Rushing, Stephanie; Hansen, Jens; Ceholski, Delaine; Kolokathis, Fotis; Kremastinos, Dimitrios; Katoulis, Alexandros; Ren, Lihuan; Cohen, Ninette; Gho, Johannes M I H; Tsiapras, Dimitrios; Vink, Aryan; Wu, Joseph C; Asselbergs, Folkert W; Li, Ronald A; Hulot, Jean-Sebastien; Kranias, Evangelia G; Hajjar, Roger J

    2015-01-01

    A number of genetic mutations is associated with cardiomyopathies. A mutation in the coding region of the phospholamban (PLN) gene (R14del) is identified in families with hereditary heart failure. Heterozygous patients exhibit left ventricular dilation and ventricular arrhythmias. Here we generate induced pluripotent stem cells (iPSCs) from a patient harbouring the PLN R14del mutation and differentiate them into cardiomyocytes (iPSC-CMs). We find that the PLN R14del mutation induces Ca(2+) handling abnormalities, electrical instability, abnormal cytoplasmic distribution of PLN protein and increases expression of molecular markers of cardiac hypertrophy in iPSC-CMs. Gene correction using transcription activator-like effector nucleases (TALENs) ameliorates the R14del-associated disease phenotypes in iPSC-CMs. In addition, we show that knocking down the endogenous PLN and simultaneously expressing a codon-optimized PLN gene reverses the disease phenotype in vitro. Our findings offer novel strategies for targeting the pathogenic mutations associated with cardiomyopathies. PMID:25923014

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

    Science.gov (United States)

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

    2016-05-01

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

  3. 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.

  4. Carbonation rates of peridotite in the Samail Ophiolite, Sultanate of Oman, constrained through 14C dating and stable isotopes

    Science.gov (United States)

    Mervine, Evelyn M.; Humphris, Susan E.; Sims, Kenneth W. W.; Kelemen, Peter B.; Jenkins, William J.

    2014-02-01

    Detailed 14C dating as well as stable C and O isotope analyses were conducted on carbonates formed during alteration of the peridotite layer of the Samail Ophiolite, Sultanate of Oman. 14C results obtained in this and previous studies indicate that surface travertines range in age from modern to >45,000 yr BP, indicating long-term deposition and preservation. Travertine deposition rates in two localities were ˜0.1 to 0.3 mm/yr between ˜30,000 and 45,000 yr BP. Using an estimate of total travertine area, this would result in a maximum of ˜1000 to 3000 m3/yr of travertine being deposited throughout the ophiolite during this time period. This travertine deposition would have sequestered a maximum of ˜1 to 3 × 106 kg CO2/yr. Ca-rich carbonate veins that are associated with the surface travertine deposits have ages ranging from ˜4000 to 36,000 yr BP (average: 15,000 yr BP). Mg-rich carbonate veins exposed in outcrops have ages ranging from ˜8000 to 45,000 yr BP (average: 35,000 yr BP). Detailed sampling from numerous locations (3 locations in this study and 10 locations in the previous studies) indicates that no carbonate veins from the natural peridotite weathering surface are older than the ˜50,000 yr BP dating limit of 14C. However, 14C dating of Mg-rich carbonate veins from three roadcut exposures (Qafeefah, Fanja, and Al-Wuqbah) indicates that a significant number of roadcut veins are 14C dead (>50,000 yr BP). A location weighted average indicates that ˜40% of veins sampled at the three roadcuts are 14C dead. An average including veins sampled at both roadcuts and outcrops indicates that overall ˜8% of Mg-rich carbonate veins are 14C dead. Mg-rich carbonate veins are estimated to sequester on the order of 107 kg CO2/yr throughout the ophiolite.

  5. Release of (14)C-labelled carbon nanotubes from polycarbonate composites.

    Science.gov (United States)

    Rhiem, Stefan; Barthel, Anne-Kathrin; Meyer-Plath, Asmus; Hennig, Michael P; Wachtendorf, Volker; Sturm, Heinz; Schäffer, Andreas; Maes, Hanna M

    2016-08-01

    Waste disposal of carbon nanotube (CNT) containing products is expected to be the most important pathway for release of CNTs into the environment. In the present work, the use of radiolabelled CNTs ((14)C-CNT) for polycarbonate polymer nanocomposites with 1 wt% (14)C-CNT content allowed for the first time to quantify and differentiate the CNT release according to the type of impact along the materials' ageing history. After an initial exposure of the nanocomposite by solar-like irradiation, further environmental impacts were applied to composite material. They aimed at mimicking disposal site conditions that may induce further ageing effects and CNT release. This study included shaking in water, rapid temperature changes, soaking in humic acid solution as well as waste water effluent, and, finally, gentle mechanical abrasion. All ageing impacts were applied sequentially, both on pristine (control) and on solar-irradiated nanocomposites. All experiments were accompanied by absolute quantification of radioactive release as well as chemical and morphological analyses of the nanocomposite surfaces using infra-red (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The morphological analysis showed that spectral irradiation can uncover CNT networks on the outer nanocomposite surface layers by polymer degradation. After having subjected the solar-irradiated nanocomposite to all studied disposal site effect, the total radioactive release was quantified to amount to 64 mg CNT/m(2), whereas only 0.8 mg CNT/m(2) were found for the un-irradiated control sample. Solar degradation of polymers was thus found to significantly increase the propensity of the studied polymer nanocomposites to release CNTs during ageing effects at the product's end-of-life typical for disposal sites. PMID:27194367

  6. Towards a global understanding of vertical soil carbon dynamics: meta-analysis of soil 14C data

    Science.gov (United States)

    hatte, C.; Balesdent, J.; Guiot, J.

    2012-12-01

    Soil represents the largest terrestrial storage mechanism for atmospheric carbon from photosynthesis, with estimates ranging from 1600 Pg C within the top 1 meter to 2350 Pg C for the top 3 meters. These values are at least 2.5 times greater than atmospheric C pools. Small changes in soil organic carbon storage could result in feedback to atmospheric CO2 and the sensitivity of soil organic matter to changes in temperature, and precipitation remains a critical area of research with respect to the global carbon cycle. As an intermediate storage mechanism for organic material through time, the vertical profile of carbon generally shows an age continuum with depth. Radiocarbon provides critical information for understanding carbon exchanges between soils and atmosphere, and within soil layers. Natural and "bomb" radiocarbon has been used to demonstrate the importance and nature of the soil carbon response to climatic and human impacts on decadal to millennial timescales. Radiocarbon signatures of bulk, or chemically or physically fractionated soil, or even of specific organic compounds, offer one of the only ways to infer terrestrial carbon turnover times or test ecosystem carbon models. We compiled data from the literature on radiocarbon distribution on soil profiles and characterized each study according to the following categories: soil type, analyzed organic fraction, location (latitude, longitude, elevation), climate (temperature, precipitation), land use and sampling year. Based on the compiled data, soil carbon 14C profiles were reconstructed for each of the 226 sites. We report here partial results obtained by statistical analyses of portion of this database, i.e. bulk and bulk-like organic matter and sampling year posterior to 1980. We highlight here 14C vertical pattern in relationship with external parameters (climate, location and land use).

  7. [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

  8. Distribution of {delta}{sup 14}C in western North Pacific and tracing carbons of human origin

    Energy Technology Data Exchange (ETDEWEB)

    Aramaki, Takafumi; Mizushima, Toshihiko; Togawa, Orihiko [Japan Atomic Energy Research Inst., Mutsu, Aomori (Japan). Mutsu Establishment; Watanabe, Shuichi; Tsunogai, Shizuo [Hokkaido Univ., Sapporo (Japan); Kuji, Tomoyuki [Japan marine Sience Fundation, Mutsu, Aomori (Japan)

    2001-02-01

    Seawater were collected at six points, 0deg to 48degN around 165degE. Dissolved inorganic carbonates was reduced into graphite. The ratio C-11/C-12 was measured by the accelerator mass analyzer. {sup 14}C concentration was calculated from {delta}{sup 13}C value calculated from the {sup 13}C/{sup 12}C ratio. {sup 14}C resulting from the nuclear weapon test was calculated by comparing estimated {sup 14}C and real {sup 14}C concentration. It was compared with that in 1970s. {sup 14}Cbomb has dissolved into North Pacific Intermediate Water in Arctic latitude, which has moved to Mid-latitude. (A. Yamamoto)

  9. Carbon and Oxygen Isotopic Stratigraphy of Mesoproterozoic Carbonate Sequences (1.6–1.4 Ga from Yanshan in North China

    Directory of Open Access Journals (Sweden)

    Kuang Hongwei

    2011-01-01

    Full Text Available In Yanshan, located in the northern part of North China, Mesoproterozoic carbonate sequences (1.6–1.4 Ga form a 10, 000 m thick succession in an aulacogen basin. Carbon and oxygen isotope (δ13O and δ18O, resp. data were obtained from 110 carbonate samples across three sections of these Mesoproterozoic deposits. From the early to late Mesoproterozoic, low negative values of δ13O appear, followed by low positive variation and then a stable increase. An abrupt decrease in δ13O values, with subsequent rapid increase, is found at the end of the Mesoproterozoic. During the whole Mesoproterozoic, δ18O shows a mainly negative trend and occasional highly negative isotopic shifts (from lower to upper deposits. Whole-rock carbon and oxygen isotopic compositions and profiles must be studied to provide a paleogeochemical record that can be associated with paleocean sedimentary environments, temperature, biological productivity, and sea-level fluctuations. Results of the present study correlate well with other international carbon and oxygen isotope profiles, suggesting that a global marine geochemical system existed during the interval of 1.6–1.4 Ga under a globally united tectonic, sedimentary, and geochemical background.

  10. Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic: 14C characteristics of sedimentary carbon components and their environmental controls

    Science.gov (United States)

    Feng, Xiaojuan; Gustafsson, Örjan; Holmes, R. Max; Vonk, Jorien E.; Dongen, Bart E.; Semiletov, Igor P.; Dudarev, Oleg V.; Yunker, Mark B.; Macdonald, Robie W.; Wacker, Lukas; Montluçon, Daniel B.; Eglinton, Timothy I.

    2015-11-01

    Distinguishing the sources, ages, and fate of various terrestrial organic carbon (OC) pools mobilized from heterogeneous Arctic landscapes is key to assessing climatic impacts on the fluvial release of carbon from permafrost. Through molecular 14C measurements, including novel analyses of suberin- and/or cutin-derived diacids (DAs) and hydroxy fatty acids (FAs), we compared the radiocarbon characteristics of a comprehensive suite of terrestrial markers (including plant wax lipids, cutin, suberin, lignin, and hydroxy phenols) in the sedimentary particles from nine major arctic and subarctic rivers in order to establish a benchmark assessment of the mobilization patterns of terrestrial OC pools across the pan-Arctic. Terrestrial lipids, including suberin-derived longer-chain DAs (C24,26,28), plant wax FAs (C24,26,28), and n-alkanes (C27,29,31), incorporated significant inputs of aged carbon, presumably from deeper soil horizons. Mobilization and translocation of these "old" terrestrial carbon components was dependent on nonlinear processes associated with permafrost distributions. By contrast, shorter-chain (C16,18) DAs and lignin phenols (as well as hydroxy phenols in rivers outside eastern Eurasian Arctic) were much more enriched in 14C, suggesting incorporation of relatively young carbon supplied by runoff processes from recent vegetation debris and surface layers. Furthermore, the radiocarbon content of terrestrial markers is heavily influenced by specific OC sources and degradation status. Overall, multitracer molecular 14C analysis sheds new light on the mobilization of terrestrial OC from arctic watersheds. Our findings of distinct ages for various terrestrial carbon components may aid in elucidating fate of different terrestrial OC pools in the face of increasing arctic permafrost thaw.

  11. The history of ironware in Japan revealed by the AMS-carbon 14 age method

    International Nuclear Information System (INIS)

    This paper focuses on the influence what the AMS-carbon 14 age method attains to the history of the iron in the Japanese Islands. The research team in National Museum of Japanese History makes a clear that the Yayoi period began in 10 Cen. cal BC. However, there was a problem in this. It is iron. If the Yayoi period has started in the 10th Cen. BC, it means that the ironware in Japanese Islands had spread early rather than it spreads in China. The research team reexamined the ironware excavated from Magarita site in the Fukuoka Pref. considered to be the oldest ironware in Japan. Consequently, the excavation situation was indefinite and it turned out that we cannot specify the time to belong. Furthermore, 36 ironwares in the initial and early Yayoi were also already found by that time cannot be specified except for two points. Therefore, it turned out that Japanese ironware appeared in the 3rd century of B.C. What does this mean? Although it had been thought that the beginning of agriculture in Japan and the appearance of ironware were simultaneous, it turned out that agriculture has appeared early about in 700 years. Therefore, it became clear that agriculture of Japan started at the Stone Age. (author)

  12. Carbon and silver nanoparticles in the fight against the filariasis vector Culex quinquefasciatus: genotoxicity and impact on behavioral traits of non-target aquatic organisms.

    Science.gov (United States)

    Murugan, Kadarkarai; Nataraj, Devaraj; Madhiyazhagan, Pari; Sujitha, Vasu; Chandramohan, Balamurugan; Panneerselvam, Chellasamy; Dinesh, Devakumar; Chandirasekar, Ramachandran; Kovendan, Kalimuthu; Suresh, Udaiyan; Subramaniam, Jayapal; Paulpandi, Manickam; Vadivalagan, Chithravel; Rajaganesh, Rajapandian; Wei, Hui; Syuhei, Ban; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Canale, Angelo; Benelli, Giovanni

    2016-03-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. The Culex genus, with special reference to Culex quinquefasciatus, comprises the most common vectors of filariasis across urban and semi-urban areas of Asia. In recent years, important efforts have been conducted to propose green-synthesized nanoparticles as a valuable alternative to synthetic insecticides. However, the mosquitocidal potential of carbon nanoparticles has been scarcely investigated. In this study, the larvicidal and pupicidal activity of carbon nanoparticle (CNP) and silver nanoparticle (AgNP) was tested against Cx. quinquefasciatus. UV-Vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and Raman analysis confirmed the rapid and cheap synthesis of carbon and silver nanoparticles. In laboratory assays, LC50 (lethal concentration that kills 50 % of the exposed organisms) values ranged from 8.752 ppm (first-instar larvae) to 18.676 ppm (pupae) for silver nanoparticles and from 6.373 ppm (first-instar larvae) to 14.849 ppm (pupae) for carbon nanoparticles. The predation efficiency of the water bug Lethocerus indicus after a single treatment with low doses of silver and carbon nanoparticles was not reduced. Moderate evidence of genotoxic effects induced by exposure to carbon nanoparticles was found on non-target goldfish, Carassius auratus. Lastly, the plant extract used for silver nanosynthesis was tested for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Overall, our results pointed out that AgNP and CNP can be a candidate for effective tools to reduce larval and pupal populations of filariasis vectors, with reduced genotoxicity and impact on behavioral traits of other aquatic organisms sharing the same ecological

  13. Evaluation of two decomposition schemes in Earth System Models against LIDET, C14 observations and global soil carbon maps

    Science.gov (United States)

    Ricciuto, D. M.; Yang, X.; Thornton, P. E.

    2015-12-01

    Soils contain the largest pool of carbon in terrestrial ecosystems. Soil carbon dynamics and associated nutrient dynamics play significant roles in regulating global carbon cycle and atmospheric CO2 concentrations. Our capability to predict future climate change depends to a large extent on a well-constrained representation of soil carbon dynamics in ESMs. Here we evaluate two decomposition schemes - converging trophic cascade (CTC) and Century - in CLM4.5/ACME V0 using data from the long-term intersite decomposition experiment team (LIDET), radiocarbon (14C) observations, and Harmonized World Soil Database (HWSD). For the evaluation against LIDET, We exercise the full CLM4.5/ ACME V0 land model, including seasonal variability in nitrogen limitation and environmental scalars (temperature, moisture, O2), in order to represent LIDET experiment in a realistic way. We show that the proper design of model experiments is crucial to model evaluation using data from field experiments such as LIDET. We also use 14C profile data at 10 sites to evaluate the performance of CTC and CENTURY decomposition scheme. We find that the 14C profiles at these sites are most sensitive to the depth dependent decomposition parameters, consistent with previous studies.

  14. Measurement of Carbon Fixation Rates in Leaf Samples — Use of carbon-14 labeled sodium bicarbonate to estimate photosynthetic rates

    OpenAIRE

    sprotocols

    2014-01-01

    Author: David R. Caprette ### Generation of a Light Curve To address the hypothesis concerning photosynthetic efficiency it is necessary to expose sun and shade leaves to a range of light intensities long enough for them to fix significant amounts of carbon. It is necessary to expose identical surface areas under favorable conditions which are identical for all leaves except for light intensity (the experimental variable). A means of measuring the rate of carbon fixation is also neces...

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

    Directory of Open Access Journals (Sweden)

    Tiantian Ye

    2015-02-01

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

  16. Volatile elements production rates in a 1.4 Gev proton-irradiated molten lead-bismuth target

    CERN Document Server

    Zanini, L; Everaerts, P; Fallot, M; Franberg, H; Gröschel, F; Jost, C; Kirchner, T; Kojima, Y; Köster, U; Lebenhaft, J; Manfrina, E; Pitcher, E J; Ravn, H L; Tall, Y; Wagner, W; Wohlmuther, M

    2005-01-01

    Production rates of volatile elements following spallation reaction of 1.4 GeV protons on a liquid Pb/Bi target have been measured. The experiment was performed at the ISOLDE facility at CERN. These data are of interest for the developments of targets for accelerator driven systems such as MEGAPIE. Additional data have been taken on a liquid Pb target. Calculations were performed using the FLUKA and MCNPX Monte Carlo codes coupled with the evolution codes ORIHET3 and FISPACT using different options for the intra-nuclear cascades and evaporation models. Preliminary results from the data analysis show good comparison with calculations for Hg and for noble gases. For other elements such as I it is apparent that only a fraction of the produced isotopes is released. The agreement with the experimental data varies depending on the model combination used. The best results are obtained using MCNPX with the INCL4/ABLA models and with FLUKA. Discrepancies are found for some isotopes produced by fission using the MCNPX ...

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

    Directory of Open Access Journals (Sweden)

    Yao HC

    2016-09-01

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

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

    Science.gov (United States)

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

    2013-07-01

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

  19. 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.

  20. 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

  1. The present status of carbon 14 analysis and projects for beryllium 10 analysis at the Tandetron 1 accelerator, Nagoya University

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshio; Oda, Hirotaka; Ikeda, Akiko; Niu, Etsuko [Nagoya Univ. (Japan)

    2001-02-01

    The operation experience in 1999 of the Tandetron accelerator age estimation system, Nagoya University, is reported, after the overview and the history of the accelerator is briefly described. Total number of carbon 14 environmental samples analyzed was 8567. The project of introducing new HVEE Tandetron for C-14 analysis, and modifying the present GIC Tandetron for Be-10 analysis is presented. Ion source shall be replaced, and the heavy ion detector shall be installed. Projected geological and archaeological studies using Be-10 are enumerated. (A. Yamamoto)

  2. Biochar, activated carbon, and carbon nanotubes have different effects on fate of (14)C-catechol and microbial community in soil.

    Science.gov (United States)

    Shan, Jun; Ji, Rong; Yu, Yongjie; Xie, Zubin; Yan, Xiaoyuan

    2015-10-30

    This study investigated the effects of biochar, activated carbon (AC)-, and single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) in various concentrations (0, 0.2, 20, and 2,000 mg/kg dry soil) on the fate of (14)C-catechol and microbial community in soil. The results showed that biochar had no effect on the mineralization of (14)C-catechol, whereas AC at all amendment rates and SWCNTs at 2,000 mg/kg significantly reduced mineralization. Particularly, MWCNTs at 0.2 mg/kg significantly stimulated mineralization compared with the control soil. The inhibitory effects of AC and SWCNTs on the mineralization were attributed to the inhibited soil microbial activities and the shifts in microbial communities, as suggested by the reduced microbial biomass C and the separated phylogenetic distance. In contrast, the stimulatory effects of MWCNTs on the mineralization were attributed to the selective stimulation of specific catechol-degraders by MWCNTs at 0.2 mg/kg. Only MWCNTs amendments and AC at 2,000 mg/kg significantly changed the distribution of (14)C residues within the fractions of humic substances. Our findings suggest biochar, AC, SWCNTs and MWCNTs have different effects on the fate of (14)C-catechol and microbial community in soil.

  3. Biochar, activated carbon, and carbon nanotubes have different effects on fate of 14C-catechol and microbial community in soil

    Science.gov (United States)

    Shan, Jun; Ji, Rong; Yu, Yongjie; Xie, Zubin; Yan, Xiaoyuan

    2015-10-01

    This study investigated the effects of biochar, activated carbon (AC)-, and single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) in various concentrations (0, 0.2, 20, and 2,000 mg/kg dry soil) on the fate of 14C-catechol and microbial community in soil. The results showed that biochar had no effect on the mineralization of 14C-catechol, whereas AC at all amendment rates and SWCNTs at 2,000 mg/kg significantly reduced mineralization. Particularly, MWCNTs at 0.2 mg/kg significantly stimulated mineralization compared with the control soil. The inhibitory effects of AC and SWCNTs on the mineralization were attributed to the inhibited soil microbial activities and the shifts in microbial communities, as suggested by the reduced microbial biomass C and the separated phylogenetic distance. In contrast, the stimulatory effects of MWCNTs on the mineralization were attributed to the selective stimulation of specific catechol-degraders by MWCNTs at 0.2 mg/kg. Only MWCNTs amendments and AC at 2,000 mg/kg significantly changed the distribution of 14C residues within the fractions of humic substances. Our findings suggest biochar, AC, SWCNTs and MWCNTs have different effects on the fate of 14C-catechol and microbial community in soil.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  5. Bayesian calibration of a soil organic carbon model using Δ14C measurements of soil organic carbon and heterotrophic respiration as joint constraints

    Science.gov (United States)

    Ahrens, B.; Reichstein, M.; Borken, W.; Muhr, J.; Trumbore, S. E.; Wutzler, T.

    2014-04-01

    Soils of temperate forests store significant amounts of organic matter and are considered to be net sinks of atmospheric CO2. Soil organic carbon (SOC) turnover has been studied using the Δ14C values of bulk SOC or different SOC fractions as observational constraints in SOC models. Further, the Δ14C values of CO2 that evolved during the incubation of soil and roots have been widely used together with Δ14C of total soil respiration to partition soil respiration into heterotrophic respiration (HR) and rhizosphere respiration. However, these data have not been used as joint observational constraints to determine SOC turnover times. Thus, we focus on (1) how different combinations of observational constraints help to narrow estimates of turnover times and other parameters of a simple two-pool model, the Introductory Carbon Balance Model (ICBM); (2) whether relaxing the steady-state assumption in a multiple constraints approach allows the source/sink strength of the soil to be determined while estimating turnover times at the same time. To this end ICBM was adapted to model SOC and SO14C in parallel with litterfall and the Δ14C of litterfall as driving variables. The Δ14C of the atmosphere with its prominent bomb peak was used as a proxy for the Δ14C of litterfall. Data from three spruce-dominated temperate forests in Germany and the USA (Coulissenhieb II, Solling D0 and Howland Tower site) were used to estimate the parameters of ICBM via Bayesian calibration. Key findings are as follows: (1) the joint use of all four observational constraints (SOC stock and its Δ14C, HR flux and its Δ14C) helped to considerably narrow turnover times of the young pool (primarily by Δ14C of HR) and the old pool (primarily by Δ14C of SOC). Furthermore, the joint use of all observational constraints made it possible to constrain the humification factor in ICBM, which describes the fraction of the annual outflux from the young pool that enters the old pool. The Bayesian parameter

  6. Validation of ten-minute single sample carbon-14 urea breath test for diagnosis of Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Prabakaran, K.; Fernandes, V.; McDonald, J. [Illawarra Regional Hospital, Wollongong, NSW (Australia). Depts of Nuclear Medicine and Gastroenterology

    1996-09-01

    Helicobacter pylori infection is traditionally diagnosed by endoscopy followed by gastric biopsy and histologic demonstration of organisms, rapid urease test and culture. The non-invasive carbon-14-urea breath test has been widely accepted now for the diagnosis of this bacterium. This study was aimed to establish and validate normal and abnormal values for an Australian population, for a single sample carbon-14-urea breath test at ten minutes. A dose of 185 kBq was used in order to achieve reasonable counting statistics. The derived values were validated with the results of the rapid urease test. This method has a high sensitivity, specificity and greater patient acceptance, and could be used in many clinical settings as the first modality for the diagnosis of H. pylori infection and for documenting response or cure after antibiotic therapy for eradication. 11 refs., 1 tab., 4 figs.

  7. Validation of ten-minute single sample carbon-14 urea breath test for diagnosis of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Helicobacter pylori infection is traditionally diagnosed by endoscopy followed by gastric biopsy and histologic demonstration of organisms, rapid urease test and culture. The non-invasive carbon-14-urea breath test has been widely accepted now for the diagnosis of this bacterium. This study was aimed to establish and validate normal and abnormal values for an Australian population, for a single sample carbon-14-urea breath test at ten minutes. A dose of 185 kBq was used in order to achieve reasonable counting statistics. The derived values were validated with the results of the rapid urease test. This method has a high sensitivity, specificity and greater patient acceptance, and could be used in many clinical settings as the first modality for the diagnosis of H. pylori infection and for documenting response or cure after antibiotic therapy for eradication. 11 refs., 1 tab., 4 figs

  8. 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

  9. An abundance of rare functional variants in 202 drug target genes sequenced in 14.002 people

    DEFF Research Database (Denmark)

    Nelson, Matthew R.; Wegmann, Daniel; Ehm, Margaret G.;

    2012-01-01

    Rare genetic variants contribute to complex disease risk; however, the abundance of rare variants in human populations remains unknown. We explored this spectrum of variation by sequencing 202 genes encoding drug targets in 14,002 individuals. We find rare variants are abundant (1 every 17 bases...... gene. We conclude that because of rapid population growth and weak purifying selection, human populations harbor an abundance of rare variants, many of which are deleterious and have relevance to understanding disease risk.......) and geographically localized, so that even with large sample sizes, rare variant catalogs will be largely incomplete. We used the observed patterns of variation to estimate population growth parameters, the proportion of variants in a given frequency class that are putatively deleterious, and mutation rates for each...

  10. 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

  11. The use of C-14 as tracer in the carbon flow assimilated by the plants (maize, sugar cane, bean)

    International Nuclear Information System (INIS)

    The flow of carbon in three different crops (maize, beans and sugar cane) was studied by use of C-14. The plants were exposed to an atmosphere with a constant concentration of the tracer for 12 hours in a biosynthesis chamber. The detection of the isotope permitted the distribution and concentration of the photosynthetates in the various organs of the plants to be followed. (M.A.C.)

  12. Comparison on the production of radionuclides in 1.4 GeV proton irradiated LBE targets of different thickness

    CERN Document Server

    Maiti, Moumita; Mendonça, Tania M; Stora, Thierry; Lahiri, Susanta

    2014-01-01

    This is the first report on the inventory of radionuclides produced in 1.4 GeV proton induced reaction on Lead-Bismuth Eutectic (LBE) targets. LBE targets of 6 mm diameter and 1 to 8 mm lengths were irradiated with 1.4 GeV protons. The radionuclides ranging from Be-7 (53.12 days) to Po-207 (5.8 h) were identified in the samples with the help of time resolved gamma-ray spectroscopy. However, there is no signature of formation of At radioisotopes, which can be produced by the interaction of secondary particles, typical for thick targets.

  13. 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...

  14. Year-round probing of soot carbon and secondary organic carbon contributions and sources to the South Asian Atmospheric Brown Cloud using radiocarbon (14C) measurements

    Science.gov (United States)

    Kirillova, Elena; Sheesley, Rebecca J.; Andersson, August; Krusâ, Martin; Safai, P. D.; Budhavant, Krishnakant; Rao, P. S. P.; Praveen, P. S.; Gustafsson, Örjan

    2010-05-01

    South Asia is one region of vital importance for assessing human impact on radiative forcing by atmospheric aerosols. Previous research in the region has indicated that black carbon is a significant component of the regional aerosol load. In contrast, there is more ambiguous information regarding the contribution of secondary organic aerosols (SOA) to the total carbonaceous (TC) aerosol composition. Here we primarily address the SOA component of the South Asian Atmospheric Brown Cloud (ABC) by a combination of measurements of SOA concentrations and the 14C signature of TC. Atmospheric particulate matter was collected during fourteen-month continuous sampling campaigns Jan 2008 - March 2009 at both the Maldives Climate Observatory at Hannimaadho (MCO-H) and at the Sinhagad hilltop sampling site of the Indian Institute of Tropical Meteorology (SIN) in central-western India. The radiocarbon method is an ideal approach to identify fossil sources (14C "dead") compared to biogenic and biomass combustion products (with a contemporary 14C signal). The radiocarbon source apportionment of TC revealed very similar contribution from biogenic/biomass combustion (60-70%) for Indian SIN site and the MCOH receptor regions for much of the year. However, during the summer monsoon season biomass contribution to TC at the Indian Ocean site increases to 70-80%, while it decreases to 40-50% at the Indian site. Source apportionment of a soot carbon (SC) isolate (CTO-375 method; a tracer of black carbon) shows a similar trend. According to preliminary data in summer biomass contribution is higher at the MCOH receptor site (70%) compared to the SIN background site (45%). These unique year-round 14C data will be interpreted in view of the SOA concentration and the varying origin of the air masses.

  15. Simulation of Carbon-14 Migration Through a Thick Unsaturated Alluvial Basin Resulting from an Underground Nuclear Explosion

    Science.gov (United States)

    Martian, P.; Larentzos, J.

    2008-12-01

    Yucca Flat is one of several areas on the Nevada Test Site that was used for underground nuclear testing. Extensive testing performed in the unsaturated and saturated zones have resulted in groundwater contamination and surface subsidence craters in the vicinity of the underground test areas. Simulation of multiphase 14C transport through the thick Yucca Flat alluvial basin was performed to estimate the magnitude of radionuclide attenuation occurring within the unsaturated zone. Parameterization of the 14C transport in the multiphase flow and transport simulator (FEHM) was verified with experimental data collected from a large unsaturated soil column experiment. The experimental data included 14C as a radio-labeled bicarbonate solution, SF6 gas, and lithium bromide solution breakthroughs. Two representative simulation cases with working points located at shallow and deep depths relative to the water table were created to investigate the impact of subsidence crater-enhanced recharge, crater-playa areal extent, gas-phase partitioning, solid-phase partitioning, and a reduced permeability/porosity compressed zone created during the explosion on 14C transport. The representative shallow test had a detonation point located 175 m below land surface, and the deep test had a working point 435 m below land surface in a 500 m deep unsaturated zone. Carbon-14 transport is influenced by gas-phase diffusion and sorption within the alluvium. Gas-phase diffusion is an attenuation mechanism that transports 14C gas as 14CO2 throughout the unsaturated zone and exposes it to a large amount of soil moisture, resulting in dilute concentrations. The simulations indicated that the majority of the 14C inventory remains in the unsaturated zone over a 1,000-year time period after detonation because gas-phase diffusion moves the bulk of the 14C away from the higher recharge occurring in crater playas. Retardation also plays a role in slowing advective aqueous phase transport to the water

  16. Use of carbon-14 for the study of elementary carbon exchange between methane and its chemisorption residues on metallic films

    International Nuclear Information System (INIS)

    After giving the results of the most recent work done with a view to providing a rational account of the exchanges between two gases in contact with a catalyst, the authors, using C14, proceed to study elementary exchange between methane and its chemisorption residues on molybdenum films. The surface is labelled in two ways: by chemisorption of C14H4 at different temperatures; or by exchange between C14H4 with a high specific activity and a metallic film previously treated with inactive methane. The C14 is counted in the form of CO2 in the Geiger region. The results show that the exchange rate is measurable from about 100o C onwards and that it reaches a maximum at about 250o C. Furthermore, the exchange is governed by laws which vary according to the prior treatment of the surface. On the basis of the results discussed, the authors suggest a methane displacement pattern which they compare with the CH4 and D2 exchange mechanisms suggested by Kemball. (author)

  17. 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

  18. Characterization of carbon-14 generated by the nuclear power industry. Final report

    International Nuclear Information System (INIS)

    This report describes an evaluation of C-14 production rates in light-water reactors (LWRs) and characterization of its chemical speciation and environmental behavior. The study estimated the total production rate of the nuclide in operating PWRs and BWRs along with the assessment of the C-14 content of solid radwaste. The major source of production of C-14 in both PWR's and BWRs was the activation of 0-17 in the water molecule and of N-14 dissolved in reactor coolant. The production of C-14 was estimated to range from 7 Ci/GW(e)-year to 11 Ci/GW(e)-year. The estimated range of the quantity of C-14 in LLW was 1-2 Ci/ reactor-year which compares favorably with data obtained from shipping manifests. The environmental behavior of C-14 associated with low-level waste (LLW) disposal is greatly dependent upon its chemical speciation. This scoping study was performed to help identify the occurrence of inorganic and organic forms of C-14 in reactor coolant water and in primary coolant demineralization resins. These represent the major source for C-14 in LLW from nuclear power stations. Also, the behavior of inorganic and two of the organic forms of C-14 on soil uptake was determined by measuring distribution coefficients (Kd's) on two soil types and a cement, using two different groundwater types. This study confirms that C-14 concentrations are significantly higher in the primary coolant from PWR stations compared to BWR stations. The C-14 followed trends of Co-60 generation during primary coolant demineralization at all but one of the stations examined. However, the C-14/Co-60 activity ratios measured by this study in resin samples through which samples of coolant were drawn were about 8 to 42 times higher than those reported for waste samples in the industry data base for PWR stations, and 15 to 730 times lower for the BWR stations

  19. Coprecipitation of (14)C and Sr with carbonate precipitates: The importance of reaction kinetics and recrystallization pathways.

    Science.gov (United States)

    Hodkin, David J; Stewart, Douglas I; Graham, James T; Burke, Ian T

    2016-08-15

    This study investigated the simultaneous removal of Sr(2+) and (14)CO3(2-) from pH>12 Ca(OH)2 solution by the precipitation of calcium carbonate. Initial Ca(2+):CO3(2-) ratios ranged from 10:1 to 10:100 (mM:mM). Maximum removal of (14)C and Sr(2+) both occurred in the system containing 10mM Ca(2+) and 1mM CO3(2-) (99.7% and 98.6% removal respectively). A kinetic model is provided that describes (14)C and Sr removal in terms of mineral dissolution and precipitation reactions. The removal of (14)C was achieved during the depletion of the initial TIC in solution, and was subsequently significantly affected by recrystallization of the calcite precipitate from an elongate to isotropic morphology. This liberated >46% of the (14)C back to solution. Sr(2+) removal occurred as Ca(2+) became depleted in solution and was not significantly affected by the recrystallization process. The proposed reaction could form the basis for low cost remediation scheme for (90)Sr and (14)C in radioactively contaminated waters (<$0.25 reagent cost per m(3) treated).

  20. 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

  1. 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.

  2. 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...

  3. Estimation of groundwater residence time using environmental radioisotopes (14C,T) in carbonate aquifers, southern Poland.

    Science.gov (United States)

    Samborska, Katarzyna; Różkowski, Andrzej; Małoszewski, Piotr

    2013-01-01

    Triassic carbonate aquifers in the Upper Silesia region, affected by intense withdrawal, have been investigated by means of isotopic analyses of (14)C, δ(13)C, δ(2)H, δ(18)O and (3)H. The isotopic examinations were carried out in the 1970s and in the early 1980s, and it was the first application of tracers to estimate age and vulnerability for the contamination of groundwater in this region. Similar isotopic analyses were conducted in 2007 and 2008 with the same Triassic carbonate formation. The isotopic examinations were performed within the confined part of the carbonate formation, wherein aquifers are covered by semi-permeable deposits. The direct recharge of the aquifer occurs in the outcrop areas, but it mainly takes place due to percolation of the water through aquitards and erosional windows. The Triassic aquifer has been intensively drained by wells and by lead-zinc mines. Nowadays, the declining water demand and closure of some mines have induced a significant increase in the water table level. The detailed analysis of the results, including the radiocarbon age corrections and the comparison of radioisotope activities, has made it possible to estimate the range of residence time within the carbonate Triassic aquifer. This range from several tens to several tens of thousands indicates that the recharge of aquifers might have occurred between modern times and the Pleistocene. The apparent age of the water estimated on the basis of (14)C activity was corrected considering the carbon isotope exchange and the diffusion between mobile water in fractures and stagnant water in micropores. The obtained corrected period of recharge corresponds to the result of investigations of noble gases, which were carried out in the 1990s. In almost half of the cases, groundwater is a mixture of young and old water. The mixing processes occur mainly in areas of heavy exploitation of the aquifer.

  4. Measurement of low level carbon-14 in biologic specimens by wet ashing

    Energy Technology Data Exchange (ETDEWEB)

    Bucks, D.; Maibach, H.

    1981-10-01

    Pharmacokinetic studies of animal and human skin are often advantageously performed with low levels of C-14. We detail an efficient wet ashing mehtod capable of detecting 20 dpm per sample, equivalent to twice the background level, thus permitting complete kinetic assays with 1 ..mu..Ci or less of C-14 per subject.

  5. Oxygen electrode reaction in molten carbonate fuel cells. Final report, September 15, 1987--September 14, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Appleby, A.J.; White, R.E.

    1992-07-07

    Molten carbonate fuel cell system is a leading candidate for the utility power generation because of its high efficiency for fuel to AC power conversion, capability for an internal reforming, and a very low environmental impact. However, the performance of the molten carbonate fuel cell is limited by the oxygen reduction reaction and the cell life time is limited by the stability of the cathode material. An elucidation of oxygen reduction reaction in molten alkali carbonate is essential because overpotential losses in the molten carbonate fuel cell are considerably greater at the oxygen cathode than at the fuel anode. Oxygen reduction on a fully-immersed gold electrode in a lithium carbonate melt was investigated by electrochemical impedance spectroscopy and cyclic voltammetry to determine electrode kinetic and mass transfer parameters. The dependences of electrode kinetic and mass transfer parameters on gas composition and temperature were examined to determine the reaction orders and the activation energies. The results showed that oxygen reduction in a pure lithium carbonate melt occurs via the peroxide mechanism. A mass transfer parameter, D{sub O}{sup 1/2}C{sub O}, estimated by the cyclic voltammetry concurred with that calculated by the EIS technique. The temperature dependence of the exchange current density and the product D{sub O}{sup 1/2}C{sub O} were examined and the apparent activation energies were determined to be about 122 and 175 kJ/ mol, respectively.

  6. 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.

  7. 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.

  8. 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

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

    Directory of Open Access Journals (Sweden)

    Elisabeth Sonnleitner

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

  10. Preliminary study of the impact of tritium and carbon 14 releases from the Saint-Alban nuclear power plant. CRIIRAD N.04-20 V1 Report

    International Nuclear Information System (INIS)

    After having recalled the results of previous studies on the radioactivity in surface water and land environments, and outlined the need of an investigation of the tritium and carbon 14 contamination, this report defines the objectives of this investigation, the adopted methodology (choice of plants, tritium and carbon 14 dose measurements, and sampling to study time variations). It recalls some aspects of tritium and carbon 14 releases (production of radionuclides, origins of emissions in the environment, assessments by EDF). It reports the investigation and the assessment of tritium activity in a land environment and in rain waters about the investigated site, and the investigation and the assessment of carbon 14 activity within the same environment. It reports preliminary results concerning the aquatic environment

  11. 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

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

    Science.gov (United States)

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

    2015-10-01

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

  13. First direct measurement of the 11C (α ,p )14N stellar reaction by an extended thick-target method

    Science.gov (United States)

    Hayakawa, S.; Kubono, S.; Kahl, D.; Yamaguchi, H.; Binh, D. N.; Hashimoto, T.; Wakabayashi, Y.; He, J. J.; Iwasa, N.; Kato, S.; Komatsubara, T.; Kwon, Y. K.; Teranishi, T.

    2016-06-01

    The 11C(α,p ) 14N reaction is an important α -induced reaction competing with β -limited hydrogen-burning processes in high-temperature explosive stars. We directly measured its reaction cross sections both for the ground-state transition (α ,p0) and the excited-state transitions (α ,p1) and (α ,p2) at relevant stellar energies 1.3-4.5 MeV by an extended thick-target method featuring time of flight for the first time. We revised the reaction rate by numerical integration including the (α ,p1) and (α ,p2) contributions and also low-lying resonances of (α ,p0) using both the present and the previous experimental data which were totally neglected in the previous compilation works. The present total reaction rate lies between the previous (α ,p0) rate and the total rate of the Hauser-Feshbach statistical model calculation, which is consistent with the relevant explosive hydrogen-burning scenarios such as the ν p process.

  14. Human sterol 14α-demethylase as a target for anticancer chemotherapy: towards structure-aided drug design.

    Science.gov (United States)

    Hargrove, Tatiana Y; Friggeri, Laura; Wawrzak, Zdzislaw; Sivakumaran, Suneethi; Yazlovitskaya, Eugenia M; Hiebert, Scott W; Guengerich, F Peter; Waterman, Michael R; Lepesheva, Galina I

    2016-08-01

    Rapidly multiplying cancer cells synthesize greater amounts of cholesterol to build their membranes. Cholesterol-lowering drugs (statins) are currently in clinical trials for anticancer chemotherapy. However, given at higher doses, statins cause serious side effects by inhibiting the formation of other biologically important molecules derived from mevalonate. Sterol 14α-demethylase (CYP51), which acts 10 steps downstream, is potentially a more specific drug target because this portion of the pathway is fully committed to cholesterol production. However, screening a variety of commercial and experimental inhibitors of microbial CYP51 orthologs revealed that most of them (including all clinical antifungals) weakly inhibit human CYP51 activity, even if they display high apparent spectral binding affinity. Only one relatively potent compound, (R)-N-(1-(3,4'-difluorobiphenyl-4-yl)-2-(1H-imidazol-1-yl)ethyl)-4-(5-phenyl-1,3,4-oxadiazol-2-yl)benzamide (VFV), was identified. VFV has been further tested in cellular experiments and found to decrease proliferation of different cancer cell types. The crystal structures of human CYP51-VFV complexes (2.0 and 2.5 Å) both display a 2:1 inhibitor/enzyme stoichiometry, provide molecular insights regarding a broader substrate profile, faster catalysis, and weaker susceptibility of human CYP51 to inhibition, and outline directions for the development of more potent inhibitors. PMID:27313059

  15. Spatial Distribution and Dynamics of Carbon-14 in a Wetland Ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Yankovich, Tamara L. [International Atomic Energy Agency, P.O. Box 100, 1400 Vienna (Austria); Carr, James; King-Sharp, K.; Doug Killey, R.W. [Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada); Robertson, Erin [201 21st Street East, Saskatoon, SK S7K 0B8 (Canada); Beresford, Nicholas A. [NERC Centre for Ecology and Hydrology, Lancaster Environment Center, Bailrigg, Lancaster, LA14AP (United Kingdom); School of Environment and Life Sciences, University of Salford, Manchester, M44WT (United Kingdom); Wood, Michael D. [School of Environment and Life Sciences, University of Salford, Manchester, M44WT (United Kingdom)

    2014-07-01

    There is significant interest in assessing the impact of {sup 14}C releases from nuclear facilities, radioactive waste management areas, and geologic disposal facilities. As a result, there is a general need to gain understanding of {sup 14}C dynamics, especially in complex interface ecosystems, such as wetlands. This paper summarizes the key findings of two studies undertaken in Duke Swamp, a circa 0.1 km{sup 2} area of wetland consisting of marsh, fen and swamp habitats, on the Atomic Energy of Canada Limited (AECL)'s Chalk River Laboratories Site. The swamp receives radionuclides, such as {sup 14}C and tritium, from an up-gradient waste management area. The first study was an extensive field sampling campaign, involving collection of surface vegetation at 69 locations on a 50 m x 50 m grid, to evaluate the spatial distribution of {sup 14}C in Duke Swamp. Representative receptor plants and animals, and corresponding environmental media (including air, soil, and plant) samples were then collected, as part of a second study, at a subset of six locations with {sup 14}C specific activities that spanned the range present in Duke Swamp and also represented the different wetland habitats occurring there. The highest specific activity concentrations in surface vegetation were highly localized, representing a surface area of only about 150 m{sup 2}. The spatial distribution of {sup 14}C in the swamp seemed to be at least partly accounted for by the physical attributes of the Duke Swamp habitat. In general, it was found that specific activities of {sup 14}C in biota tissues reflected those measured in surface vegetation collected from the same sampling location. Such information provides needed insight for biosphere assessments, as well as for the development of monitoring programs that demonstrate protection of biota in areas where exposure to {sup 14}C is elevated. (authors)

  16. 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

  17. [Tritium- and carbon-14-contents of wines of different vintage from the northern and southern hemisphere (author's transl)].

    Science.gov (United States)

    Fischer, E; Möller, H; Rapp, A; Steffan, H

    1980-10-01

    The carbon-14 and tritium radioactivity contents of up to 19 vintages of German and South African wines were compared. A similar large dependence of the 14C- and of the 3H-activity in the German wine on the nuclear weapon tests of the years 1962/63 was found out. The radioactivity level is also 1977/78 still essential higher than before 1950. The South African wines have been influenced considerably smaller by nuclear explosions. The highest 3H-values were found in the vintage 1963 of the German wine with 5910 pCi/litre and in the vintage 1964 of the South African wine with 510 pCi/litre.

  18. 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.

  19. 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.

  20. Concentration and 14C Content of Total Organic Carbon and Black Carbon in Small (<100 ug C) Samples from Low-Latitude Alpine Ice Cores

    Science.gov (United States)

    Kehrwald, N. M.; Czimczik, C. I.; Santos, G. M.; Thompson, L. G.; Ziolkowski, L.

    2008-12-01

    Many low latitude glaciers are receding with consequences for the regional energy budget and hydrology. Ice loss has been linked to climate change and the deposition of organic aerosols such as black carbon (BC) which is formed during incomplete combustion. Little is known about how the contents of BC and total organic carbon (TOC) in aerosols change over time and how anthropogenic activities (e.g. land-use change) impact this variability. Low-latitude ice cores are located closer to population centers than polar ice caps and can provide a regional synthesis of TOC and BC variability. Radiocarbon (14C) may be used to partition BC aerosols into fossil (>50 kyrs) and modern sources (e.g. fossil-fuels vs. wildfires). We quantified TOC, BC, and their 14C content in three low-latitude ice cores: Naimona'nyi (30°27'N, 81°91'E) and Dasuopu (28°23'N, 85°43'E), Tibet, and Quelccaya (13°56'S; 70°50'W), Peru. Aerosols (52-256 g ice on filters) were separated into TOC and BC using thermal oxidation (CTO- 375). 14C was measured by AMS. TOC contents were 0.11-0.87, 0.05-0.43, and 0.06-0.19 μg C (g ice) -1 for Naimona'nyi, Dasuopu, and Quelccaya, respectively. BC contents were 18±8, 27±4, and 29±12 %TOC. Procedural blanks were 0.8 ± 0.4 μg C (TOC) and 1.2 ± 0.6 μg C (BC). In ice cores well dated through annual layer counting and/or independent ages (e.g. volcanic horizons) such as Quelccaya, the ability to separate BC from TOC, as well as partition BC into fossil and modern contributions has potential for reconstructing pre- and post-industrial changes in aerosol composition and their impact on the energy budget.

  1. Carbon and 14C distribution in tropical and subtropical agricultural soils

    Science.gov (United States)

    Prastowo, Erwin; Grootes, Pieter; Nadeau, Marie

    2016-04-01

    Paddy soil management affects, through the alternating anoxic and oxic conditions it creates, the transport and stabilisation of soil organic matter (SOM). Irrigation water may percolate more organic materials - dissolved (DOM) and colloidal - into the subsoil during anoxic conditions. Yet a developed ploughpan tends to prevent C from going deeper in the subsoil and partly decouple C distribution in top and sub soil. We investigate the influence of different soil type and environment. We observed the C and 14C distribution in paddy and non-paddy soil profiles in three different soil types from four different climatic regions of tropical Indonesia, and subtropical China. Locations were Sukabumi (Andosol, ca. 850 m a.s.l), Bogor (clayey Alisol, ca. 240 m a.s.l), and Ngawi (Vertisol, ca. 70 m a.s.l) in Jawa, Indonesia, and Cixi (Alisol(sandy), ca. 4 - 6 m a.s.l) in Zhejiang Province, China. We compared rice paddies with selected neighbouring non-paddy fields and employed AMS 14C as a tool to study C dynamics from bulk, alkali soluble-humic, and insoluble humin samples, and macrofossils (plant remains, charcoal). Our data suggest that vegetation type determines the quantity and quality of biomass introduced as litter and root material in top and subsoil, and thus contributes to the soil C content and profile, which fits the 14C signal distribution, as well as 13C in Ngawi with C4 sugar cane as upland crop. 14C concentrations for the mobile humic acid fraction were generally higher than for bulk samples from the same depth, except when recent plant and root debris led to high 14C levels in near-surface samples. The difference in sampling, - averaged layer for bulk sample and 1-cm layer thickness for point sample - shows gradients in C and 14C across the layers, which could be a reason for discrepancies between the two. High 14C concentrations - in Andosol Sukabumi up to 111 pMC - exceed the atmospheric 14CO2concentration in the sampling year in 2012 (˜ 103 pMC) and

  2. Evaluation of carbon-14 (C{sup 14}) levels of terrestrial and marine food products of the environment of the site of Cogema La Hague; Evaluation des niveaux de carbone-14 ({sup 14}C) des denrees alimentaires terrestres et marines de l'environnement du site de COGEMA - La Hague

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-04-15

    This evaluation has for object to inform about the levels in carbon 14 in the environment of the factories of La Hague. Two sectors were differentiated on one hand the terrestrial environment, and on the other hand the marine environment. The investigations concerned first and foremost food products stemming as the vegetable culture (vegetables) or individual breeding (milk, eggs) but also foodstuffs stemming from the local agriculture (cereal). In touch with the second sector, the marine environment, the sampling concerned the accessible products of the sea by all and those locally marketed (fishes, molluscs, shellfishes). The different results are presented in tables. (N.C.)

  3. Radiobiological half-lives for carbon-14 and hydrogen-3 leucine in man

    International Nuclear Information System (INIS)

    In vivo estimates of protein metabolism in many are often made by oral or intravenous administration of leucine or its ∼-ketoacid, ∼-ketoisocaproate, labeled with 14C or 3H. Previous estimates of radiation dose from such tracers have been based on the measurement of 14CO2 in breath. Using measurements of the decay of 3H or 14C leucine from plasma proteins, longer biological half-lives for these compounds were obtained. The estimated total-body radiation absorbed dose is 0.97 mrad/uCi for [1-14C]KIC (or [1-14C]leucine) and 0.11 mrad/+Ci for ]4,5-3H]leucine (or [3H]KIC). Assuming administered doses of 100 μCi each, the total-body radiation absorbed dose is still well within the limits set by the FDA for Radioactive Drug Research Committees. 12 references, 3 figures, 3 tables

  4. Contribution of sorption, DOC transport and microbial interactions to the 14C age of a soil organic carbon profile: Insights from a calibrated process model

    NARCIS (Netherlands)

    Ahrens, B.; Braakhekke, M.C.; Guggenberger, G.; Schrumpf, M.; Reichstein, M.

    2015-01-01

    Profiles of soil organic carbon (SOC) are often characterized by a steep increase of 14C age with depth, often leading to subsoil 14C ages of more than 1000 years. These observations have generally been reproduced in SOC models by introducing a SOC pool that decomposes on the time-scale of millennia

  5. A comet could not produce the carbon-14 spike in the 8th century

    CERN Document Server

    Usoskin, Ilya

    2014-01-01

    A mysterious increase of radiocarbon 14C ca. 775 AD in the Earth's atmosphere has been recently found by Miyake et al. (Nature, 486, 240, 2012). A possible source of this event has been discussed widely, the most likely being an extreme solar energetic particle event. A new exotic hypothesis has been presented recently by Liu et al. (Nature Sci. Rep., 4, 3728, 2014) who proposed that the event was caused by a comet bringing additional 14C to Earth. Here we calculated a realistic mass and size of such a comet to show that it would have been huge (~100 km across and 10^{14}-10^{15} ton of mass) and would have produced a disastrous impact on Earth. Such an impact could not remain unnoticed in the geological records and chronicles. The absence of an evidence for such a dramatic event makes this hypothesis invalid.

  6. Proteomic identification of protein targets for 15-deoxy-Δ(12,14-prostaglandin J2 in neuronal plasma membrane.

    Directory of Open Access Journals (Sweden)

    Yasuhiro Yamamoto

    Full Text Available 15-deoxy-Δ(12,14-prostaglandin J(2 (15d-PGJ(2 is one of factors contributed to the neurotoxicity of amyloid β (Aβ, a causative protein of Alzheimer's disease. Type 2 receptor for prostaglandin D(2 (DP2 and peroxysome-proliferator activated receptorγ (PPARγ are identified as the membrane receptor and the nuclear receptor for 15d-PGJ(2, respectively. Previously, we reported that the cytotoxicity of 15d-PGJ(2 was independent of DP2 and PPARγ, and suggested that 15d-PGJ(2 induced apoptosis through the novel specific binding sites of 15d-PGJ(2 different from DP2 and PPARγ. To relate the cytotoxicity of 15d-PGJ(2 to amyloidoses, we performed binding assay [(3H]15d-PGJ(2 and specified targets for 15d-PGJ(2 associated with cytotoxicity. In the various cell lines, there was a close correlation between the susceptibilities to 15d-PGJ(2 and fibrillar Aβ. Specific binding sites of [(3H]15d-PGJ(2 were detected in rat cortical neurons and human bronchial smooth muscle cells. When the binding assay was performed in subcellular fractions of neurons, the specific binding sites of [(3H]15d-PGJ(2 were detected in plasma membrane, nuclear and cytosol, but not in microsome. A proteomic approach was used to identify protein targets for 15d-PGJ(2 in the plasma membrane. By using biotinylated 15d-PGJ(2, eleven proteins were identified as biotin-positive spots and classified into three different functional proteins: glycolytic enzymes (Enolase2, pyruvate kinase M1 (PKM1 and glyceraldehyde 3-phosphate dehydrogenase (GAPDH, molecular chaperones (heat shock protein 8 and T-complex protein 1 subunit α, cytoskeletal proteins (Actin β, F-actin-capping protein, Tubulin β and Internexin α. GAPDH, PKM1 and Tubulin β are Aβ-interacting proteins. Thus, the present study suggested that 15d-PGJ(2 plays an important role in amyloidoses not only in the central nervous system but also in the peripheral tissues.

  7. On the labelling of insuline and insuline derivatives with tritium and carbon-14

    International Nuclear Information System (INIS)

    Two different labelling methods were investigated. By means of the Wilzbach labelling with diaminosuberoylinsuline the insuline is irreversibly altered. As a second method the reductive methylation was used, in doing so it was possible to distinguish between mono and dimethylated parts of the reaction product by using C-14 labelled formaldehyde. Furthermore four N,N-dimethylated insuline derivatives were isolated with yields of 25 until 35%. By using C-14 and h-3 labelled reagents insuline can be labelled doubly. Moreover N-terminal amino groups could be protected irreversibly with this method. Furthermore structure-function investigations and investigations concerning the insuline metabolism were done. (SPI)

  8. Targeted Gene Disruption of the 14-α Sterol Demethylase (cyp51A) in Aspergillus fumigatus and Its Role in Azole Drug Susceptibility

    OpenAIRE

    Mellado, E.; Garcia-Effron, G.; Buitrago, M. J.; Alcazar-Fuoli, L.; Cuenca-Estrella, M.; Rodriguez-Tudela, J. L.

    2005-01-01

    The role of Aspergillus fumigatus 14α-sterol demethylase (Cyp51A) in azole drug susceptibility was assessed. Targeted disruption of cyp51A in azole-susceptible and -resistant strains decreased MICs from 2- to 40-fold. The cyp51A mutants were morphologically indistinguishable from the wild-type strain, retaining the ability to cause pulmonary disease in neutropenic mice.

  9. Carbon beam extraction with 14.5 GHz electron cyclotron resonance ion source at Korea Atomic Energy Research Institute

    Science.gov (United States)

    Lee, Cheol Ho; Oh, Byung-Hoon; Chang, Dae-Sik; Jeong, Sun-Chan

    2014-02-01

    A 14.5 GHz Electron Cyclotron Resonance ion source (ECRIS) has been made to produce C4+ beam for using a carbon therapy facility and recently tested at KAERI. Highly charged carbon ions have been successfully extracted. When using only CO2 gas, the beam current of C4+ was almost 14 μA at 15 kV extraction voltage. To get higher current of the C4+ beam, while optimizing confinement magnetic field configuration (e.g., axial strengths at minimum and extraction side), gas-mixing (CO2/He), and biased disk were introduced. When the gas mixing ratio of the CO2/He gas is 1:8 at an operational pressure of 5 × 10-7 mbar and the disk was biased to -150 V relative to the ion source body, the highest current of the C4+ beam was achieved to be 50 μA, more than three times higher than previously observed only with CO2 gas. Some details on the operating conditions of the ECRIS were discussed.

  10. Carbon-14 based determination of the biogenic fraction of industrial CO2 emissions : Application and validation

    NARCIS (Netherlands)

    Palstra, S. W. L.; Meijer, H. A. J.

    2010-01-01

    The C-14 method is a very reliable and sensitive method for industrial plants, emission authorities and emission inventories to verify data estimations of biogenic fractions of CO2 emissions. The applicability of the method is shown for flue gas CO2 samples that have been sampled in I-h intervals at

  11. Carbon-14 labelled nitrogen heterocycles; the syntheses of three phosphodiesterase inhibitors

    International Nuclear Information System (INIS)

    The syntheses of three heterocyclic phosphodiesterase inhibitors are described from a common radiolabelled precursor, namely 2-propoxybenzo[cyano-14C] nitrile. Conversion of the nitrile to the corresponding methyl ketone or amidine allows elaboration of the heterocycles radiolabelled within the ring systems. (Author)

  12. Constraints on emissions of carbon monoxide, methane, and a suite of hydrocarbons in the Colorado Front Range using observations of 14CO2

    OpenAIRE

    LaFranchi, B. W; Pétron, G.; Miller, J. B.; S. J. Lehman; Andrews, A. E; E. J. Dlugokencky; Hall, B.; Miller, B. R.; Montzka, S. A.; W. Neff; P. C. Novelli; C. Sweeney; J. C. Turnbull; D. E. Wolfe; P. P. Tans

    2013-01-01

    Atmospheric radiocarbon (14C) represents an important observational constraint on emissions of fossil-fuel derived carbon into the atmosphere due to the absence of 14C in fossil fuel reservoirs. The high sensitivity and precision that accelerator mass spectrometry (AMS) affords in atmospheric 14C analysis has greatly increased the potential for using such measurements to evaluate bottom-up emissions inventories of fossil fuel CO2 (CO2ff), as well as those for other co-emitte...

  13. Interactive effects between carbon allotropes on the mechanical reinforcement of nanocomposites based on poly(1,4-cis-isoprene)

    Science.gov (United States)

    Musto, Sara; Cipolletti, Valeria; Barbera, Vincenzina; Agnelli, Silvia; Pandini, Stefano; Galimberti, Maurizio

    2014-05-01

    Interactive effects of carbon allotropes on the mechanical reinforcement of polymer nanocomposites were investigated by using, as the polymer matrix, poly(1,4-cis-isoprene) (PI) samples from industrial synthesis and from natural sources. Carbon nanotubes (CNT) and nano-graphite with high shape anisotropy (nanoG) were melt blended with PI, as the only fillers or in combination with carbon black (CB), measuring the shear modulus at low strain amplitudes. The nanofiller was found to increase the low amplitude storage modulus of the matrix, with or without CB, by a factor depending on nanofiller type and content. The filler-polymer interfacial area was able to correlate modulus data of composites with CNT, CB and with the hybrid filler system, leading to the construction of a common master curve. The filler networking phenomenon was found to be affected by type and amount of low molecular mass products of PI from natural sources. The correlation between chemical composition, dynamic mechanical and ultimate properties of nanocomposites was investigated. In particular, it was found that low molecular mass components control the ability of elastomeric nano-composites to store or dissipate energy.

  14. Characterization of airborne particulates by pyrolysis/mass spectrometry and carbon-14 analysis

    Energy Technology Data Exchange (ETDEWEB)

    Voorhees, K.J. (Colorado School of Mines, Golden); Durfee, S.L.; Currie, L.A.; Klouda, G.A.

    1981-08-01

    Pyrolysis/mass spectrometry (Py/MS) has been used to characterize the composition of organics in an ambient air particulate sample from the eastern Utah oil shale lands. The procedure involved collection of the individual contributors, pyrolysis of these samples, and finally a least-squares fitting of the individual contributor spectra to the pyrolysis mass spectrum of the ambient sample. The Py/MS results were verified by using /sup 14/C analysis.

  15. A synthetic approach to carbon-14 labeled anti-bacterial naphthyridine and quinolone carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Ekhato, I.V.; Huang, C.C. (Parke, Davis and Co., Ann Arbor, MI (United States))

    1993-09-01

    Labeled versions of (S)-clinafloxacin (1) and two napththyridine carboxylic acid anti-bacterial compounds 2 and 3 which are currently in development were synthesized. Preparations started from hitherto unknown bromo compounds 22 and 10, from which the corresponding [sup 14]C-labeled aromatic carboxylic acids 23 and 12 were generated by metal-halogen exchange followed by carboxylation reaction. Details of these preparations are given. (author).

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

    Science.gov (United States)

    Lavalleur, Heather J; Colwell, Frederick S

    2013-07-01

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

  17. Effects of entrainment through Oconee Nuclear Station on carbon-14 assimilation rates of phytoplankton

    International Nuclear Information System (INIS)

    Carbon assimilation rates of phytoplankton communities entrained through Oconee Nuclear Station were measured on six dates during 1974. Thermal, mechanical, condenser, and multiple entrainment effects on uptake rates were compared by incubating samples in vitro in controlled-temperature water baths. Duplicate light and dark bottles containing water from four cooling-system locations were exposed to temperatures approximating intake and discharge temperatures. The relationships were variable, but exposure of the hypolimnetic intake water at near-discharge temperatures (thermal effect) stimulated primary productivity in four of six experiments. Multiple entrainment and mechanical effects caused no consistent change in assimilation rates

  18. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-15

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

  20. Correction of human phospholamban R14del mutation associated with cardiomyopathy using targeted nucleases and combination therapy

    OpenAIRE

    Karakikes, Ioannis; Stillitano, Francesca; Nonnenmacher, Mathieu; Tzimas, Christos; Sanoudou, Despina; Termglinchan, Vittavat; Kong, Chi-Wing; Rushing, Stephanie; Hansen, Jens; Ceholski, Delaine; Kolokathis, Fotis; Kremastinos, Dimitrios; Katoulis, Alexandros; Ren, Lihuan; Cohen, Ninette

    2015-01-01

    International audience A number of genetic mutations is associated with cardiomyopathies. A mutation in the coding region of the phospholamban (PLN) gene (R14del) is identified in families with hereditary heart failure. Heterozygous patients exhibit left ventricular dilation and ventricular arrhyth-mias. Here we generate induced pluripotent stem cells (iPSCs) from a patient harbouring the PLN R14del mutation and differentiate them into cardiomyocytes (iPSC-CMs). We find that the PLN R14del...

  1. 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.

  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. Carbon-14 ages of Antarctic meteorites with accelerator and small-volume counting techniques

    International Nuclear Information System (INIS)

    C-14 measurements were made on six Yamato and Victoria Land meteorites using tandem accelerator mass spectroscopy. The studies brought to 27 the number of Antarctic meteorites that have been examined for terrestrial aging. Details of the spectroscopic method are provided, along with the results in combinations with the data from the other 21 meteorites. It is found that the Yamato meteorites are younger than those found at Allan Hills, implying that two mechanisms may exist for the abundant Antarctic meteorites: exposure where falling due to a paucity of ice, and transport and exposure by sublimating ice

  4. Age determination of ground-waters by means of carbon 14

    International Nuclear Information System (INIS)

    At present the age determination of ground-waters aged between 1,500 and approximately 40,000 years is only possible by measuring their 14C content. A precise age assignment can be established in slightly mineralised waters, whereas it becomes vague in mineralised waters, particularly in acidulous springs. In general, additional information and data are required about the 13C, D, 18O, 3H, 85Kr and the 39Ar contents, about the ph value, temperature and the principal ions. (DG)

  5. Carbon Nanotube and Nanofiber Exposure Assessments: An Analysis of 14 Site Visits.

    Science.gov (United States)

    Dahm, Matthew M; Schubauer-Berigan, Mary K; Evans, Douglas E; Birch, M Eileen; Fernback, Joseph E; Deddens, James A

    2015-07-01

    Recent evidence has suggested the potential for wide-ranging health effects that could result from exposure to carbon nanotubes (CNT) and carbon nanofibers (CNF). In response, the National Institute for Occupational Safety and Health (NIOSH) set a recommended exposure limit (REL) for CNT and CNF: 1 µg m(-3) as an 8-h time weighted average (TWA) of elemental carbon (EC) for the respirable size fraction. The purpose of this study was to conduct an industrywide exposure assessment among US CNT and CNF manufacturers and users. Fourteen total sites were visited to assess exposures to CNT (13 sites) and CNF (1 site). Personal breathing zone (PBZ) and area samples were collected for both the inhalable and respirable mass concentration of EC, using NIOSH Method 5040. Inhalable PBZ samples were collected at nine sites while at the remaining five sites both respirable and inhalable PBZ samples were collected side-by-side. Transmission electron microscopy (TEM) PBZ and area samples were also collected at the inhalable size fraction and analyzed to quantify and size CNT and CNF agglomerate and fibrous exposures. Respirable EC PBZ concentrations ranged from 0.02 to 2.94 µg m(-3) with a geometric mean (GM) of 0.34 µg m(-3) and an 8-h TWA of 0.16 µg m(-3). PBZ samples at the inhalable size fraction for EC ranged from 0.01 to 79.57 µg m(-3) with a GM of 1.21 µg m(-3). PBZ samples analyzed by TEM showed concentrations ranging from 0.0001 to 1.613 CNT or CNF-structures per cm(3) with a GM of 0.008 and an 8-h TWA concentration of 0.003. The most common CNT structure sizes were found to be larger agglomerates in the 2-5 µm range as well as agglomerates >5 µm. A statistically significant correlation was observed between the inhalable samples for the mass of EC and structure counts by TEM (Spearman ρ = 0.39, P 1 μg m(-3). Until more information is known about health effects associated with larger agglomerates, it seems prudent to assess worker exposure to airborne CNT and CNF

  6. 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

  7. 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.

  8. 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...

  9. 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...

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

    Science.gov (United States)

    Foresti, Roberta; Motterlini, Roberto

    2010-12-01

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

  11. Paleo-vegetation study using dating by 14 C and carbon isotope ratio

    International Nuclear Information System (INIS)

    Different approaches that include biological, geomorphological and botanical studies have been used to infer past climatic changes in the Amazon. Our approach involve the use of 13 C analyses in soil organic matter to infer past vegetation changes based on distinct isotopic composition that characterize C3 and C4 plants, and 14 C is used as dating tool, in two regions of natural Forest and Cerrado, located in Rondonia state. The soil at the Forest site is Podzolico Vermelho Amarelo and the Cerrado site is a Latosol Vermelho Amarelo. Radiocarbon analyses of total soil fraction samples indicate that the organic matter in these soils is at least Holocene in age δ13 C values for total soil organic matter in the forest varies from-28 at the surface to 25% at depth of 2 m, indicating the predominance of a C3 cycle in the last 3 270 yrs. At the Cerrado the δ13 C change from -21 to -14% in the first 30 cm characterizing C4 cycle and changed to -19% at 135 cm, probably characterizing a mixture between C3 and C4 plants and an increase to -16% is observed at 195 cm, again indicating a predominance of C4 plants. This data show that the Cerrado ecosystem was much more dynamics in term of vegetation changes than Forest. (author). 10 refs, 2 figs, 1 tab

  12. Recent results at the SIRa test bench Diffusion properties of carbon graphite and B sub 4 C targets

    CERN Document Server

    Landre-Pellemoine, F; Bajeat, O; Barue, C; Bennett, R; Clapier, F; Ducourtieux, M; Gaubert, G; Gibouin, S; Huguet, Y; Jardin, P; Kandri-Rody, S; Lau, C; Lecesne, N; Leroy, R; Lewitowicz, M; Lichtenthäler, R; Marry, C; Maunoury, L; Obert, J; Orr, N A; Pacquet, J Y; Saint-Laurent, M G; Stodel, C; Rataud, J P; Villari, A C C

    2002-01-01

    The diffusion properties of graphite targets with 1, 4 and 15 microns microstructure has been measured for He and Ar isotopes. An important enhancement of the diffusion efficiency for the smaller microstructure is observed. A releasing efficiency of the order of 100% was obtained for sup 6 He (T sub 1 sub / sub 2 =806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B sub 4 C (boron carbide) have also been studied. Yields of 1.4x10 sup 8 pps and 5.0x10 sup 5 pps for sup 6 He and sup 8 He has been obtained.

  13. 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.

  14. The effect of local anatomy on the electric field induced by TMS: evaluation at 14 different target sites.

    Science.gov (United States)

    Janssen, Arno M; Oostendorp, Thom F; Stegeman, Dick F

    2014-10-01

    Many human cortical regions are targeted with transcranial magnetic stimulation (TMS). The stimulus intensity used for a certain region is generally based on the motor threshold stimulation intensity determined over the motor cortex (M1). However, it is well known that differences exist in coil-target distance and target site anatomy between cortical regions. These differences may well make the stimulation intensity derived from M1 sub-optimal for other regions. Our goal was to determine in what way the induced electric fields differ between cortical target regions. We used finite element method modeling to calculate the induced electric field for multiple target sites in a realistic head model. The effects on the electric field due to coil-target distance and target site anatomy have been quantified. The results show that a correction based on the distance alone does not correctly adjust the induced electric field for regions other than M1. In addition, a correction based solely on the TMS-induced electric field (primary field) does not suffice. A precise adjustment should include coil-target distance, the secondary field caused by charge accumulation at conductivity discontinuities and the direction of the field relative to the local cerebrospinal fluid-grey matter boundary.

  15. Assessment of experimental d-PIGE γ-ray production cross sections for 12C, 14N and 16O and comparison with absolute thick target yields

    Science.gov (United States)

    Csedreki, L.; Halász, Z.; Kiss, Á. Z.

    2016-08-01

    Measured differential cross sections for deuteron induced γ-ray emission from the reactions 12C(d,pγ)13C, (Eγ = 3089 keV), 14N(d,pγ)15N (Eγ = 8310 keV) and 16O(d,pγ)17O (Eγ = 871 keV) available in the literature were assessed. In order to cross check the assessed γ-ray production cross section data, thick target γ-yields calculated from the differential cross sections were compared with available measured thick target yields. Recommended differential cross section data for each reaction were deduced for particle induced γ-ray emission (PIGE) applications.

  16. Enzymatic determination of carbon-14 labeled L-alanine in biological samples

    International Nuclear Information System (INIS)

    A method for determination of L-alanine-specific radioactivity in biological samples is presented. This method is based on the specific enzymatic transformation of L-alanine to pyruvic acid hydrazone catalyzed by the enzyme L-alanine dehydrogenase, formation of the pyruvic acid 2,4-dinitrophenylhydrazone derivative, and quantitative trapping in Amberlite XAD-7 columns, followed by radioactivity counting of the lipophilic eluate. No interferences from other 14C-labeled materials such as D-glucose, glycerol, L-lactate, L-serine, L-glutamate, L-phenylalanine, glycine, L-leucine, and L-arginine were observed. This inexpensive and high-speed method is applicable to the simultaneous determination of L-alanine-specific radioactivity for a large number of samples

  17. Partitioning sources of recharge in environments with groundwater recirculation using carbon-14 and CFC-12

    Science.gov (United States)

    Bourke, Sarah A.; Cook, Peter G.; Dogramaci, Shawan; Kipfer, Rolf

    2015-06-01

    Groundwater recirculation occurs when groundwater is pumped from an aquifer onto the land surface, and a portion of that water subsequently infiltrates back to the aquifer. In environments where groundwater is recirculated, differentiation between various sources of recharge (e.g. natural rainfall recharge vs. recirculated water) can be difficult. Groundwater age indicators, in particular transient trace gases, are likely to be more sensitive tracers of recharge than stable isotopes or chloride in this setting. This is because, unlike stable isotopes or chloride, they undergo a process of equilibration with the atmosphere, and historical atmospheric concentrations are known. In this paper, groundwater age indicators (14C and CFC-12) were used as tracers of recharge by surplus mine water that is discharged to streams. Ternary mixing ratios were calculated based on 14C and CFC-12 concentrations measured along three transects of piezometers and monitoring wells perpendicular to the creeks, and from dewatering wells. Uncertainty in calculated mixing ratios was estimated using a Monte Carlo approach. Ternary mixing ratios in dewatering wells suggest that recharge by mine water accounted for between 10% and 87% of water currently abstracted by dewatering wells. The calculated mixing ratios suggest that recharge by mine water extends to a distance of more than 550 m from the creeks. These results are supported by seepage flux estimates based on the water and chloride balance along the creeks, which suggest that 85-90% of mine water discharged to the creeks recharges the aquifer and recharge by mine water extends between 110 and 730 m from the creeks. Mixing calculations based on gaseous groundwater age indicators could also be used to partition recharge associated with agricultural irrigation or artificial wetland supplementation.

  18. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-04

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

  20. 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.

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

    Directory of Open Access Journals (Sweden)

    Alicia eCourties

    2015-07-01

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

  2. 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)

  3. Catalytic hydrogenation of carbon monoxide. Progress report, December 15, 1991--December 14, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Wayland, B.B.

    1992-12-01

    This project is focused on developing strategies to accomplish the reduction and hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. Our approaches to this issue are based on the recognition that rhodium macrocycles have unusually favorable thermodynamic values for producing a series of intermediate implicated in the catalytic hydrogenation of CO. Observations of metalloformyl complexes produced by reactions of H{sub 2} and CO, and reductive coupling of CO to form metallo {alpha}-diketone species have suggested a multiplicity of routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in constructing energy profiles for a variety of potential pathways, and these schemes are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Variation of the electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Emerging knowledge of the factors that contribute to M-H, M-C and M-O bond enthalpies is directing the search for ligand arrays that will expand the range of metal species that have favorable thermodynamic parameters to produce the primary intermediates for CO hydrogenation. Studies of rhodium complexes are being extended to non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics. Multifunctional catalyst systems designed to couple the ability of rhodium complexes to produce formyl and diketone intermediates with a second catalyst that hydrogenates these imtermediates are promising approaches to accomplish CO hydrogenation at mild conditions.

  4. Metabolism and distribution of 14C- and 35S-labeled carbon disulfide in immature rats of different ages

    International Nuclear Information System (INIS)

    The metabolism and distribution of 14C- and 35S-CS2 was examined in 1-, 5-, 10-, 20-, 30-, and 40-day-old rats. During a 3-hr period following an ip dose of 14C-CS2, 58-83% of the dose was expired as CS2 and 4-9% was metabolized to expired CO2 depending on age. Thirty- and forty-day-old rats metabolized significantly more CS2 to CO2 and expired significantly less CS2 than 1- through 20-day-old rats. At the end of the measured expiration period, only biotransformation products of CS2, which were in part covalently bound, remained in tissues from rats of all ages. Tissue levels of 35S-CS2-derived radioactivity exceeded levels of 14C-CS2-derived radioactivity indicating that sulfur metabolites free from the carbon atom of CS2 were formed in rats as young as 1 day of age. The 35S-CS2-derived radioactivity per g of tissue and thus 35S covalently bound to tissue protein was significantly higher in 1- through 20-day-old rats than in 30- and 40-day-old rats. Twenty-four hr after dosing, up to 13 times more 35S-labeled metabolites were covalently bound in organs from 1-day-old rats than in similar organs from 40-day-old rats. The results showed that elimination of the biotransformation products of CS2, in particular the covalently binding sulfur metabolites, was prolonged in newborn rats in comparison to 40-day-old rats

  5. Soil aggregate fraction-based 14C analysis and its application in the study of soil organic carbon turnover under forests of different ages

    Institute of Scientific and Technical Information of China (English)

    TAN WenBing; ZHOU LiPing; LIU KeXin

    2013-01-01

    There still exist uncertainties in the trend,magnitude and efficiency of carbon sequestration with regard to the changes in soil organic carbon (SOC) pools after afforestation.In this study,SOC turnover times of the meadow steppe and planted forests at Saihanba Forest Station of Hebei Province,China are estimated by means of the radiocarbon (14C) method.Our results show that the SOC turnover times can be as long as from 70 to 250 years.After planting the Pinus sylvestri var.mongolica in the Leymus chinensis meadow steppe,the turnover times of organic carbon in both bulk samples and soil aggregate fractions of the topsoils are decreased with an increase of the stand age.Such a lowering of the turnover time would cause an increase in soil CO2 flux,implying that afforestation of grassland may reduce the capacity of topsoil to sequestrate organic carbon.Combined stable isotope and 14C analyses on soil aggregate fractions suggest that there are different responses to afforestation of grassland between young and old carbon pools in topsoils.In the young and middle-age planted forests,the proportion of CO2 emission from the older soil carbon pool shows an increasing trend.But in the mature planted forest,its proportion tends to decline,indicating that the stand age may influence the soil carbon sequestration mechanism.The CO2 emission from the topsoils estimated using the 14C method is relatively low compared to those by other methods and may be caused by the partial isolation of the young carbon component from the soil aggregates.For more accurate estimation of CO2 flux,future studies should therefore employ improved methodology for more effective separation of different soil carbon components before isotope analyses.

  6. Synthesis of carbon-14 labelled CD 271 (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid): a potential new agent for dermatology

    International Nuclear Information System (INIS)

    6-[3-(1-Adamantyl)-4-methoxyphenyl]-2-naphthoic acid, a promising new compound for the treatment of disorders of keratinization, has been synthesized in [14C]-labelled form from barium[14C]-carbonate via labelled benzene. Benzene-[U-14C] was converted to 4-bromo-methoxybenzene-[phenyl-U-14C] in six steps. Introduction of the adamantyl ring was carried out using 1-acetoxyadamantane under acid catalysis. 2-(1-Adamantyl)-4-bromo-methoxybenzene-[phenyl-U-14C] was converted to a zincate and coupled with methyl 6-bromo-2-naphthoate using a nickel catalyst. The product of the aryl coupling reaction was then saponified to give 6-[3-(1-adamantyl)-4-methoxyphenyl-[phenyl-U-14C

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-06-01

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

  9. 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

  10. 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.

  11. 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)

  12. 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.

  13. Carbon-14 transfer into potato plants following a short exposure to an atmospheric 14CO2 emission: observations and model predictions.

    Science.gov (United States)

    Melintescu, A; Galeriu, D; Tucker, S; Kennedy, P; Siclet, F; Yamamoto, K; Uchida, S

    2013-01-01

    To improve the understanding of the environmental (14)C behaviour, the International Atomic Energy Agency (IAEA) coordinated a Tritium and C-14 Working Group (T&C WG) in its EMRAS (Environmental Modelling for Radiation Safety) programme. One of the scenarios developed in the frame of T&C WG involved the prediction of time dependent (14)C concentrations in potato plants. The experimental data used in the scenario were obtained from a study in which potatoes (Solanum tuberosum cv. Romano) were exposed to atmospheric (14)CO(2) in a wind tunnel. The observations were used to test models that predict temporal changes in (14)C concentrations in leaves at each sampling time for each experiment and (14)C concentrations in tubers at the final harvest of each experiment. The experimental data on (14)C dynamics in leaves are poorly reproduced by most of the models, but the predicted concentrations in tubers are in good agreement with the observations. PMID:22995861

  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. Nuclear graphite waste's behaviour under disposal conditions: Study of the release and repartition of organic and inorganic forms of carbon 14 and tritium in alkaline media

    International Nuclear Information System (INIS)

    23000 tons of graphite wastes will be generated during dismantling of the first generation of French reactors (9 gas cooled reactors). These wastes are classified as Long Lived Low Level wastes (LLW-LL). As requested by the law, the French National Radioactive Waste Management Agency (Andra) is studying concepts of low-depth disposals.In this work we focus on carbon 14, the main long-lived radionuclide in graphite waste (5730 y), but also on tritium, which is the main contributor to the radioactivity in the short term. Carbon 14 and tritium may be released from graphite waste in many forms in gaseous phase (14CO2, HT...) or in solution (14CO32-, HTO...). Their speciation will strongly affect their migration from the disposal site to the environment. Leaching experiments, in alkaline solution (0.1 M NaOH simulating repository conditions) have been performed on irradiated graphite, from Saint-Laurent A2 and G2 reactors, in order to quantify their release and characterize their speciation. The studies show that carbon 14 exists in both gaseous and aqueous phases. In the gaseous phase, release is weak (≤0.1%) and corresponds to oxidizable species. Carbon 14 is mainly released into liquid phase, as both inorganic and organic species. 65% of released fraction is inorganic and 35% organic carbon. Two tritiated species have been identified in gaseous phase: HTO and HT/Organically Bond Tritium. More than 90% of tritium in that phase corresponds to HT/OBT. But release is weak (≤0.1%). HTO is mainly in the liquid phase. (author)

  17. 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

  18. A quantitative 14-3-3 interaction screen connects the nuclear exosome targeting complex to the DNA damage response

    DEFF Research Database (Denmark)

    Blasius, Melanie; Wagner, Sebastian A; Choudhary, Chuna Ram;

    2014-01-01

    RNA metabolism is altered following DNA damage, but the underlying mechanisms are not well understood. Through a 14-3-3 interaction screen for DNA damage-induced protein interactions in human cells, we identified protein complexes connected to RNA biology. These include the nuclear exosome...

  19. Correction of human phospholamban R14del mutation associated with cardiomyopathy using targeted nucleases and combination therapy

    NARCIS (Netherlands)

    Karakikes, Ioannis; Stillitano, Francesca; Nonnenmacher, Mathieu; Tzimas, Christos; Sanoudou, Despina; Termglinchan, Vittavat; Kong, Chi-Wing; Rushing, Stephanie; Hansen, Jens; Ceholski, Delaine; Kolokathis, Fotis; Kremastinos, Dimitrios; Katoulis, Alexandros; Ren, Lihuan; Cohen, Ninette; Gho, Johannes M. I. H.; Tsiapras, Dimitrios; Vink, Aryan; Wu, Joseph C.; Asselbergs, Folkert W.; Li, Ronald A.; Hulot, Jean-Sebastien; Kranias, Evangelia G.; Hajjar, Roger J.

    2015-01-01

    A number of genetic mutations is associated with cardiomyopathies. A mutation in the coding region of the phospholamban (PLN) gene (R14del) is identified in families with hereditary heart failure. Heterozygous patients exhibit left ventricular dilation and ventricular arrhythmias. Here we generate i

  20. Targeting Antibodies to Carbon Nanotube Field Effect Transistors by Pyrene Hydrazide Modification of Heavy Chain Carbohydrates

    Directory of Open Access Journals (Sweden)

    Steingrimur Stefansson

    2012-01-01

    Full Text Available Many carbon nanotube field-effect transistor (CNT-FET studies have used immobilized antibodies as the ligand binding moiety. However, antibodies are not optimal for CNT-FET detection due to their large size and charge. Their size can prevent ligands from reaching within the Debye length of the CNTs and a layer of charged antibodies on the circuits can drown out any ligand signal. In an attempt to minimize the antibody footprint on CNT-FETs, we examined whether pyrene hydrazide modification of antibody carbohydrates could reduce the concentration required to functionalize CNT circuits. The carbohydrates are almost exclusively on the antibody Fc region and this site-specific modification could mediate uniform antibody orientation on the CNTs. We compared the hydrazide modification of anti-E. coli O157:H7 polyclonal antibodies to pyrenebutanoic acid succinimidyl ester-coated CNTs and carbodiimide-mediated antibody CNT attachment. Our results show that the pyrene hydrazide modification was superior to those methods with respect to bacteria detection and less than 1 nM labeled antibody was required to functionalize the circuits.

  1. 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

  2. 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

  3. 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)

  4. 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

  5. Ventilation of the deep Greenland and Norwegian seas: evidence from krypton-85, tritium, carbon-14 and argon-39

    International Nuclear Information System (INIS)

    On leg 5 of the TTO expedition, the distributions of 85Kr, tritium, 14C, 39Ar, temperature, salinity, oxygen, carbon dioxide and nutrients were measured in the Greenland and Norwegian seas. These observations support previous observations that Greenland Sea Deep Water is formed by a deep convective process within the Greenland gyre. They also support AAGAARD et al.'s (1985, Journal of Geophysical Research, 90, 4833-4846) new hypothesis that Norwegian Sea Deep Water forms from a mixture of Greenland Sea Deep Water and Eurasian Basin Deep Water. Volume transports estimated from the distributions of 85Kr, tritium, 14C and 39Ar range from 0.53 to 0.74 Sv for exchange between the surface and deep Greenland Sea and from 0.9 to 1.47 Sv for exchange between the deep Greenland and deep Norwegian Seas. The residence time of water and the deep Greenland Sea with respect to exchange with surface water ranges from 24 to 34 years reported by PETERSON and ROOTH (1976, Deep-Sea Research, 23, 273-283) and 35-42 years reported by BULLISTER and WEISS (1983, Science, 221, 265-268). The residence time of water in the deep Norwegian Sea with respect to exchange with the deep Greenland Sea ranges from 19 to 30 years compared to 97-107 years reported by PETERSON and ROOTH (1976) and 10-28 years reported by BULLISTER and WEISS (1983). The oxygen consumption rate was estimated to be at most 1.04 μM kg-1 y-1 for the deep Greenland Sea and to be between 0.47 and 0.79 μM kg-1 y-1 for the deep Norwegian Sea. (author)

  6. Accuracy and precision of 14C-based source apportionment of organic and elemental carbon in aerosols using the Swiss_4S protocol

    Directory of Open Access Journals (Sweden)

    G. O. Mouteva

    2015-04-01

    Full Text Available Aerosol source apportionment remains a critical challenge for understanding the transport and aging of aerosols, as well as for developing successful air pollution mitigation strategies. The contributions of fossil and non-fossil sources to organic carbon (OC and elemental carbon (EC in carbonaceous aerosols can be quantified by measuring the radiocarbon (14C content of each carbon fraction. However, the use of 14C in studying OC and EC has been limited by technical challenges related to the physical separation of the two fractions and small sample sizes. There is no common procedure for OC/EC 14C analysis, and uncertainty studies have largely focused on the precision of yields. Here, we quantified the uncertainty in 14C measurement of aerosols associated with the isolation and analysis of each carbon fraction with the Swiss_4S thermal-optical analysis (TOA protocol. We used an OC/EC analyzer (Sunset Laboratory Inc., OR, USA coupled to vacuum line to separate the two components. Each fraction was thermally desorbed and converted to carbon dioxide (CO2 in pure oxygen (O2. On average 91% of the evolving CO2 was then cryogenically trapped on the vacuum line, reduced to filamentous graphite, and measured for its 14C content via accelerator mass spectrometry (AMS. To test the accuracy of our set-up, we quantified the total amount of extraneous carbon introduced during the TOA sample processing and graphitization as the sum of modern and fossil (14C-depleted carbon introduced during the analysis of fossil reference materials (adipic acid for OC and coal for EC and contemporary standards (oxalic acid for OC and rice char for EC as a function of sample size. We further tested our methodology by analyzing five ambient airborne particulate matter (PM2.5 samples with a range of OC and EC concentrations and 14C contents in an interlaboratory comparison. The total modern and fossil carbon blanks of our set-up were 0.8 ± 0.4 and 0.67 ± 0.34 μg C

  7. Accuracy and precision of 14C-based source apportionment of organic and elemental carbon in aerosols using the Swiss_4S protocol

    Science.gov (United States)

    Mouteva, G. O.; Fahrni, S. M.; Santos, G. M.; Randerson, J. T.; Zhang, Y.-L.; Szidat, S.; Czimczik, C. I.

    2015-09-01

    Aerosol source apportionment remains a critical challenge for understanding the transport and aging of aerosols, as well as for developing successful air pollution mitigation strategies. The contributions of fossil and non-fossil sources to organic carbon (OC) and elemental carbon (EC) in carbonaceous aerosols can be quantified by measuring the radiocarbon (14C) content of each carbon fraction. However, the use of 14C in studying OC and EC has been limited by technical challenges related to the physical separation of the two fractions and small sample sizes. There is no common procedure for OC/EC 14C analysis, and uncertainty studies have largely focused on the precision of yields. Here, we quantified the uncertainty in 14C measurement of aerosols associated with the isolation and analysis of each carbon fraction with the Swiss_4S thermal-optical analysis (TOA) protocol. We used an OC/EC analyzer (Sunset Laboratory Inc., OR, USA) coupled to a vacuum line to separate the two components. Each fraction was thermally desorbed and converted to carbon dioxide (CO2) in pure oxygen (O2). On average, 91 % of the evolving CO2 was then cryogenically trapped on the vacuum line, reduced to filamentous graphite, and measured for its 14C content via accelerator mass spectrometry (AMS). To test the accuracy of our setup, we quantified the total amount of extraneous carbon introduced during the TOA sample processing and graphitization as the sum of modern and fossil (14C-depleted) carbon introduced during the analysis of fossil reference materials (adipic acid for OC and coal for EC) and contemporary standards (oxalic acid for OC and rice char for EC) as a function of sample size. We further tested our methodology by analyzing five ambient airborne particulate matter (PM2.5) samples with a range of OC and EC concentrations and 14C contents in an interlaboratory comparison. The total modern and fossil carbon blanks of our setup were 0.8 ± 0.4 and 0.67 ± 0.34 μg C, respectively

  8. 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)

  9. New {sup 230}Th/U and {sup 14}C ages from Lake Lahontan carbonates, Nevada, USA, and a discussion of the origin of initial thorium

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.C.; Broecker, W.S.; Anderson, R.F. [Lamont-Doherty Earth Observatory of Columbia Univ., Palisades, NY (United States)] [and others

    1996-08-01

    Five sets of coeval lacustrine carbonate samples from Pleistocene Lake Lahontan in western Nevada were dated by both the AMS {sup 14}C and {sup 230}Th/U isochron methods. All five groups of samples were analyzed for U-Th isotopes by alpha spectrometry and one of the groups was additionally measured by thermal and secondary ionization mass spectrometry (TIMS and SIMS) for comparison. The {sup 14}C ages were corrected to calendar years using the calibration curve recommended by Bard et al. (1992). Without local reservoir correction on the {sup 14}C ages mean {sup 230}Th/U isochron ages of some sets are apparently older than their calendar-corrected {sup 14}C ages by up to 2300 years. Modern carbon contamination of these carbonate samples through recrystallization or deposition of secondary calcite is likely to be responsible for part of the age discrepancies. We explored additional biases associated with the isochron ages, maybe produced by the presence of initial Th coprecipitated from the lake water. It can be shown that if dissolved (hydrogenous) Th is directly incorporated into the pure carbonates, then the three-component mixing among (1) detrital Th, (2) hydrogenous Th adsorbed on detritus, and (3) hydrogenous Th incorporated by the carbonate can introduce a positive age bias. We have developed an approach to estimate the magnitude of this bias of the Lake Lahontan carbonates. The preliminary estimates suggest a positive age bias of 1000 to 2000 years for two sets of the samples. 49 refs., 10 figs., 9 tabs.

  10. Effects of time passage and distance on distribution of carbon-14 among parts of rice during growth period at Korean CANDU plant

    International Nuclear Information System (INIS)

    The pattern of carbon-14 (C-14) distribution among parts of rice growing in the vicinity of the Korean CANDU plant during the growth period was investigated. Six-time samplings of rice and air were performed in seven fields from rice planting to harvest, and the measurements of C-14 content were made by using liquid scintillation counter on the air and each of available parts of the rice such as root, stem, crust and ear. The results illustrated that C-14 showed a relatively even distribution among parts of rice during the growth period implying C-14 accumulation was more dependent on interactions among the parts such as transportation of nutrients than on photosynthesis occurring only in stem that has chlorophyll. Also it was observed that the difference of C-14 concentration between each part of rice and the air decreased with time indicating that the time was needed for C-14 to reach equilibrium between both sides. The radius within which C-14 released from the Wolsong plant could have a significant effect on the C-14 concentrations of the parts was observed to be about 5 km. (author)

  11. Study of heavy products formed by rare earth target bombardment by 12C and 14N from 5 to 30 MeV/nucleon

    International Nuclear Information System (INIS)

    The individual evaporation residue cross sections have been measured for 12C and 14N induced reactions on 141Pr, 144Sm, 147Sm, 150Sm, 152Sm, 154Sm targets at energies of 5 to 30 MeV/nucleon. Gamma-ray detection techniques were used. Between 5 and 10 MeV/nucleon the observed mass and charge distributions are interpreted in terms of evaporation from compound nuclei. Statistical model calculations reproduce well the increasing charged particle emission far off the stability line. At 15 and 30 MeV/nucleon the reaction mechanism observed is different. The experimental results are interpreted in terms of the average mass transfer between projectile and target. This interpretation, based on the evaporation calculations, is consistent with the experimental systematic of the decrease of linear momentum transfer with projectile velocity

  12. The evolution of a tropical rainforest/grassland mosaic in southeastern Brazil since 28,000 14C yr BP based on carbon isotopes and pollen records

    Science.gov (United States)

    Ruiz Pessenda, Luiz Carlos; De Oliveira, Paulo Eduardo; Mofatto, Milene; de Medeiros, Vanda Brito; Francischetti Garcia, Ricardo José; Aravena, Ramon; Bendassoli, José Albertino; Zuniga Leite, Acácio; Saad, Antonio Roberto; Lincoln Etchebehere, Mario

    2009-05-01

    The lack of paleoecological records from the montane Atlantic Rainforest of coastal Brazil, a hotspot of biological diversity, has been a major obstacle to our understanding of the vegetational changes since the last glacial cycle. We present carbon isotope and pollen records to assess the impact of the glaciation on the native vegetation of the Serra do Mar rainforest in São Paulo, Brazil. From ca. 28,000 to ˜ 22,000 14C yr BP, a subtropical forest with conifer trees is indicative of cool and humid conditions. In agreement carbon isotopic data on soil organic matter suggest the presence of C 3 plants and perhaps C 4 plants from ˜ 28,000 to ˜ 19,000 14C yr BP. The significant increase in the sedimentation rate and algal spores from ˜ 19,450 to ˜ 19,000 14C yr BP indicates increasing humidity, associated to an erosion process between ˜ 19,000 and ˜ 15,600 14C yr BP. From ˜ 15,600 14C yr BP to present there is a substantial increase in arboreal elements and herbs, indicating more humid and warmer climate. From ˜ 19,000 to ˜ 1000 14C yr BP, δ 13C values indicated the predominance of C 3 plants. These results are in agreement with studies in speleothems of caves, which suggest humid conditions during the last glacial maximum.

  13. Targeted full-genome amplification and sequencing of dengue virus types 1-4 from South America.

    Science.gov (United States)

    Cruz, Cristopher D; Torre, Armando; Troncos, Gilda; Lambrechts, Louis; Leguia, Mariana

    2016-09-01

    We report optimized workflows for full-genome sequencing of dengue viruses (DENVs) 1-4. Based on alignments of publicly available complete genomes we modified and expanded existing primers sets to amplify DENV genotypes that were previously difficult or impossible to sequence. We also report improvements to streamline laboratory handling, including a dual amplification strategy for easy and difficult to sequence "high-copy" and "low-copy" templates, respectively, and normalization of PCR cycling conditions across serotypes. High-copy templates can be sequenced following amplification of as few as 5 overlapping segments covering the complete viral genome, whereas low-copy templates can be sequenced following amplification of no more than 10 overlapping segments of smaller size. These changes have been validated using a balanced set of wild-type DENV genomes (11 of DENV1, 14 of DENV2, 13 of DENV3 and 7 of DENV4) derived from human serum samples collected throughout South America over the past 15 years. The changes described enable generation of complete DENV genomes from wild-type samples without the need for viral enrichment via passaging through laboratory cell lines. This should facilitate quick and cost-effective generation of DENV full-genome sequences of the type needed for accurate epidemiological surveillance and thorough evolutionary studies of wild-type DENVs. PMID:27334982

  14. 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

  15. Experimental urolithiasis : Part V - Role of dietary carbonate in the etiology of the disease using radioactive 14C-potassium bicarbonate

    International Nuclear Information System (INIS)

    Incorporation of 14C-potassium bicarbonate in rat kidney, bladder, blood and bladder contents was assessed to study the role of dietary carbonate in urolithiasis. Male rats (23) were fed carbonate-free diet and water, 19 of which were surgically induced for bladder stones and the remaining sham-operated. Total elimination of carbonate both from diet and drinking water lowered the incidence of stone by 63% as compared with a parallel group fed normal diet and tap water. At sacrifice, 5 μCi of 14C-KHCO3 were injected (ip) into each animal. Higher counts in the serum and kidney, than that in the contents of the bladder were noted on both types of diet. Feeding of normal diet and tap water, led to a significant increase (P14C uptake, and their relative distribution (as indicated by the total counts incorporated) in the various tissues of stoneformers and non-stoneformers as compared to controls, reflects individual differences in the handling of carbonate by each tissue. (auth.)

  16. Cross section measurements using gas and solid targets for production of the positron-emitting radionuclide O-14

    CERN Document Server

    Kovács, Z; Tarkanyi, F; Coenen, H H; Qaim, S M

    2003-01-01

    Irradiation of nitrogen with protons leads to sup 1 sup 1 C (T sub 1 sub / sub 2 =20.4min) via the well-known sup 1 sup 4 N(p,alpha) reaction. However, sup 1 sup 4 O (T sub 1 sub / sub 2 =70.6s) and sup 1 sup 3 N (T sub 1 sub / sub 2 =10min) are also formed as side products via the sup 1 sup 4 N(p,n) and sup 1 sup 4 N(p,d+pn) reactions, respectively. In this work detailed cross section measurements were carried out for those two side reactions up to 19.2MeV using N sub 2 gas and nitrogen-containing solid targets. From the data, the thick-target yields and the exact level of radioactive impurities in sup 1 sup 1 C were calculated. In the case of sup 1 sup 4 O, the results also confirmed the possibility of producing this beta sup + emitting radionuclide in sufficient quantities for PET investigations.

  17. Test of the suitability of ECOPATH/ECOSIM modelling software as a compliment to estimate flows of carbon, C-14 and radionuclides in the Oeregrundsgrepen area

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, Johannes [Stockholm Univ. (Sweden). Dept. of Systems Ecology

    2004-04-01

    In this study it was evaluated whether the ECOPATH with ECOSIM software could be used as a standard platform to facilitate for radioecologists to construct and study transport and accumulation of radionuclides in aquatic food webs. The evaluation was based upon: 1) a previously published food web model of carbon/carbon-14 flow for the Oeregrundsgrepen area, Baltic Sea, 2) a generic model, 3) an ECOSIM model and 4) an ECOTRACE model. The results presented clearly shows that there is great potential for a successful development of this scientific approach in the future. The original carbon flows and assumptions was easily incorporated into the ECOPATH with ECOSIM modelling environment. The carbon flows differed only negligible between the two models, except for the benthic flows, which was more accurately described in this study. Further, by using ECOPATH it was easily discovered that the growth efficiencies used in the original model was quite high, being 47% for most of the heterotrophs, which are high from an ecological point of view. However, that is probably due to differences in how the carbon flows have been estimated in the original versus the present study. It is likely, however that the carbon demand has been underestimated in the original model. The generic model was parameterised from data available through the software as well from the diets and assumptions used in the original carbon model. The use of these parameters resulted in carbon flows, which was between 0.7 to 11 times the flows estimated by the ECOPATH model. The difference was greatest for primary producers being 3.7 to 11 times the original flows. Thus, depending on the question one is addressing it was suggested that the use of generic parameters is best for making test models of carbon and radionuclide flows in ecosystems, where the data set for validation is limited. Finally, the ECOPATH and ECOSIM model was well suited to drive a C-14 flow model, such as ECOTRACER for each of the

  18. Test of the suitability of ECOPATH/ECOSIM modelling software as a compliment to estimate flows of carbon, C-14 and radionuclides in the Oeregrundsgrepen area

    International Nuclear Information System (INIS)

    In this study it was evaluated whether the ECOPATH with ECOSIM software could be used as a standard platform to facilitate for radioecologists to construct and study transport and accumulation of radionuclides in aquatic food webs. The evaluation was based upon: 1) a previously published food web model of carbon/carbon-14 flow for the Oeregrundsgrepen area, Baltic Sea, 2) a generic model, 3) an ECOSIM model and 4) an ECOTRACE model. The results presented clearly shows that there is great potential for a successful development of this scientific approach in the future. The original carbon flows and assumptions was easily incorporated into the ECOPATH with ECOSIM modelling environment. The carbon flows differed only negligible between the two models, except for the benthic flows, which was more accurately described in this study. Further, by using ECOPATH it was easily discovered that the growth efficiencies used in the original model was quite high, being 47% for most of the heterotrophs, which are high from an ecological point of view. However, that is probably due to differences in how the carbon flows have been estimated in the original versus the present study. It is likely, however that the carbon demand has been underestimated in the original model. The generic model was parameterised from data available through the software as well from the diets and assumptions used in the original carbon model. The use of these parameters resulted in carbon flows, which was between 0.7 to 11 times the flows estimated by the ECOPATH model. The difference was greatest for primary producers being 3.7 to 11 times the original flows. Thus, depending on the question one is addressing it was suggested that the use of generic parameters is best for making test models of carbon and radionuclide flows in ecosystems, where the data set for validation is limited. Finally, the ECOPATH and ECOSIM model was well suited to drive a C-14 flow model, such as ECOTRACER for each of the

  19. {sup 14}C chronology of the oldest Scandinavian church in use. An AMS/PIXE study of lime lump carbonate in the mortar

    Energy Technology Data Exchange (ETDEWEB)

    Lindroos, Alf, E-mail: alf.lindroos@abo.fi [Geology and Mineralogy, Department of Natural Sciences, Åbo Akademi University (Finland); Art History, Faculty of Art, Åbo Akademi University (Finland); Ranta, Heikki [Diocese of Lund, Church of Sweden (Sweden); Heinemeier, Jan [AMS " 1" 4C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark); Lill, Jan-Olof [Accelerator Laboratory, Turku PET Centre, Åbo Akademi University (Finland)

    2014-07-15

    Mortar dating was applied to newly revealed, original mortar in the church of Dalby in Scania, southern Sweden which is considered to be the oldest still standing church in Scandinavia. Small white lime lumps were sampled by chipping from the supporting pillars in the interior of the church. Special emphasis was in sampling lime lumps because the church is situated in the Scania limestone area and aggregate limestone contamination was anticipated in the bulk mortars. Earlier studies have, however, shown that lime lumps do not contain aggregate material but only possible limestone rests from incomplete calcination. The sampled material was prepared for radiocarbon AMS dating. The carbonate in the lime lumps was hydrolyzed according to the sequential leaching technique developed for the Århus {sup 14}C laboratory in Denmark. Prior to the hydrolysis the lime lumps were examined for dead-carbon contamination using a stereo microscope and cathodoluminescence. The lime lumps displayed heterogeneous carbonate luminescence. This is, however, common and it was not considered a problem because carbonate growth in changing pH/Eh conditions often leads to changing luminescence colors. Two lumps had little dead carbon contamination and an early second millennium {sup 14}C signature. One lump, however, seemed to be heavily contaminated with dead carbon. Since the sample passed the microscopic screening, the leftovers of the lump was subjected to PIXE analysis and compared with the other two lumps. The well-defined, early 2nd millennium {sup 14}C age of the lime lumps of this particular church is an important contribution to the discussion on stone church chronology in Scandinavia.

  20. 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)

  1. 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

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

    Science.gov (United States)

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

    2016-10-01

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

  3. 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.

  4. 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

  5. Nature and Origin of Variations in Late-Glacial and Holocene Atmospheric CARBON-14 as Revealed by Global Carbon Cycle Modeling

    Science.gov (United States)

    Braziunas, Thomas Frank

    1990-01-01

    Simulations with a global box-diffusion ^{14}C model indicate that the millennium- and century-scale atmospheric Delta ^{14}C variations during the Holocene are more likely explained by fluctuations in ^ {14}C production rate (Q) than by changes in air-sea CO_2 exchange rate (F) or internal ocean mixing (parameterized as an "eddy diffusivity" K_{rm z}. The ^{14}C reservoir model deconvolves histories for each of these three processes that are compatible with a 96-yr bi-decadal atmospheric (tree-ring)Delta^{14}C record assuming alternative pre-Holocene ^ {14}C conditions. Holocene microparticle concentrations in ice cores and dust grain sizes in marine sediment cores disagree with the model-derived global wind speeds necessary to explain (through F variations) the millennium-scale trends in atmospheric Delta ^{14}C. Alternately, foram ^{14}C data do not support the history in the oceanic ventilation index generated by millennium -scale K_{rm z} variations. Coral ^{14}C data for recent centuries conflict with the marine Delta ^{14}C history associated with century-scale variations in F or K_{ rm z} but are consistent with changes in ^{14}C production rate. The ^{14}C production rates derived theoretically from an 11,000-yr record of averaged global dipole moments strongly correlate with the Q history required to explain tree-ring Delta ^{14}C. Several pre-Holocene Q histories were calculated from limited dipole moment data available for the past 30,000 yrs and do not contradict ^{234}U/^ {230}Th-calibrated coral ^ {14}C measurements. Relative variations in Greenland ice-core ^{10}Be concentrations (reflecting changes in ^ {10}Be production) over the past 9000 yrs also correlate strongly with tree-ring Q fluctuations except for a 4500-3500 BC discrepancy. Simulations of transient variations in Q, F, and K_{rm z} supplement previous studies of alternative steady-state ^ {14}C situations. The modeling of combined climate and production rate scenarios (i.e. F + K _{rm z

  6. Jean-François Gallotte, Joëlle Malberg, Carbone 14 le film, Les Mutins de Pangée

    OpenAIRE

    Curien, Julie

    2014-01-01

    Carbone 14 le film est un témoignage sur le mouvement des radios libres, à travers l'exemple de « Carbone 14 », « la radio active » devenue « la radio qui vous encule par les oreilles ». Filmé en 4 jours à la rentrée 1982, avec du matériel volé, le film ovni de Jean-François Galotte et Joëlle Malberg est sélectionné au Festival de Cannes en 1983. Il fait un tollé qui retombe comme une crêpe, aux oubliettes : on n'en parle plus avant... 2011, trente ans après la création de la radio culte et c...

  7. Le carbone 14 : progrès récents et limitations de la méthode de datation

    OpenAIRE

    J. C. Duplessy; Arnold, M; Bard, E.; Cortijo, E.; Labeyrie, L.; Laj, C.; Lehman, B; Mazaud, A.; M. Paterne; Tisnerat, N.; L. Vidal

    1998-01-01

    La méthode de datation par le carbone 14 a permis l'établissement d'une échelle chronologique du Quaternaire Supérieur et a contribué à la découverte de phénomènes insoupçonnés comme l'existence de variations climatiques abruptes et de grande amplitude pendant la dernière période glaciaire et la déglaciation qui l'a terminée. L'effort continu pour comparer les âges carbone 14 avec les âges calendaires a été maintenant étendu au delà de 30 000 ans, même si le nombre de mesures est encore trop ...

  8. AMS-{sup 14}C measurements for the carbonate platform of the offshore Campos Basin, Rio de Janeiro State, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Coimbra, Melayne M. E-mail: melayne@onda.com.br; Barbosa, Catia F.; Soares-Gomes, Abilio; Silva, Cleverson G.; Rios-Netto, Aristoteles; Mueller, Ken A

    2000-10-01

    As part of our accelerator mass spectrometry (AMS) program in Brazil we prepared and measured some red algae carbonate crust samples from Campos Basin, Rio de Janeiro, Brazil. The measurements were performed at Purdue Rare Isotope Measurement Laboratory (PRIME Lab), Purdue University, IN, USA. This carbonate material is interlaminated with foraminiferal lime mud reflecting recurrent intervals of carbonate development, which might be linked to outer-shelf oceanographic circulation.

  9. 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.

  10. Synthesis of carbon-14 labelled (5Z)-4-bromo-5-(bromomethylene)-2(5H)-furanone:

    DEFF Research Database (Denmark)

    Persson, T.; Johansen, S.K.; Martiny, L.;

    2004-01-01

    The potent quorum sensing inhibitor (5Z)-4-bromo-5-(bromomethylene)-2(5H)-[2-C-14]furanone has been prepared in five steps in 7.7% overall yield starting from bromo[1-C-14]acetic acid. Condensation of ethyl bromo[1-C-14]acetate with ethyl acetoacetate followed by decarboxylation was accelerated...

  11. On 14C-based methods for measuring the biogenic carbon fraction in fuels and flue gases

    NARCIS (Netherlands)

    Palstra, Sanne Waltje Lieze

    2016-01-01

    Several international regulations distinguish between carbon from biomass and carbon from fossil raw materials for different materials and CO2 emissions. Due to these regulations it can be financially beneficial for companies to claim for instance their products to originate from 100% biomass, that

  12. Carbon cycling in primary production bottle incubations: inferences from grazing experiments and photosynthetic studies using 14C and 18O in the Arabian Sea

    Science.gov (United States)

    Laws, Edward A.; Landry, Michael R.; Barber, Richard T.; Campbell, Lisa; Dickson, Mary-Lynn; Marra, John

    Estimates of photosynthesis based on the incorporation of 14C-labeled inorganic carbon into particulate carbon were compared to estimates of gross photosynthesis based on net O 2 production and the production of 18O2 from H218O during the US Joint Global Ocean Flux Study (US JGOFS) Arabian Sea process cruises. For samples incubated below the surface and at optical depthsMehler reaction, photorespiration, dark respiration, excretion, and grazing effects on the two estimates of photosynthesis. The 14C uptake : gross photosynthesis ratio was distinctly higher (0.62) for samples incubated at the surface. This result is likely due to UV light effects, since the O 2 and 14C incubations were done in quartz and polysulfone bottles, respectively. The 14C uptake : gross photosynthesis ratio was lower (0.31) for bottles incubated at optical depths>3. This result probably reflects an increase in the ratio of dark respiration to net photosynthesis in the vicinity of the compensation light level.

  13. 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.

  14. Synthesizing the Use of Carbon Isotope (14C and 13C) Approaches to Understand Rates and Pathways for Permafrost C Mobilization and Mineralization

    Science.gov (United States)

    Estop-Aragones, C.; Olefeldt, D.; Schuur, E.

    2015-12-01

    To better understand the permafrost carbon (C) feedback it is important to synthesize our current knowledge, and knowledge gaps, of how permafrost thaw can cause in situ mineralization or downstream mobilization of aged soil organic carbon (SOC) and the rate of this release. This potential loss of old SOC may occur via gaseous flux of CO2 and CH4 exchanged between soil and the atmosphere and via waterborne flux as DOC, POC (and their subsequent decomposition and release to the atmosphere). Carbon isotope (14C and 13C) approaches have been used to estimate both rates and pathways for permafrost C mobilization and mineralization. Radiocarbon (14C) has been used to estimate the contribution of aged C to overall respiration or waterborne C export. We aim to contrast results from radiocarbon studies, in order to assess differences between ecosystems (contrasting wet and dry ecosystems), thaw histories (active layer deepening or thermokarst landforms), greenhouse gas considered (CO2 and CH4) and seasons. We propose to also contrast methodologies used for assessing the contribution of aged C to overall C balance, and include studies using 13C data. Biological fractionation of 13C during both uptake and decomposition has been taken advantage of both in order to aid the interpretation of 14C data and on its own to assess sources and mineralization pathways. For example, 13C data has been used to differentiate between CH4 production pathways, and the relative contribution of anaerobic CO2 production to overall respiration. Overall, carbon isotope research is proving highly valuable for our understanding of permafrost C dynamics following thaw, and there is a current need to synthesize the available literature.

  15. Synthesis and purification of carbon-14 labelled 1, 1-hexamethylene-bis [5-(4-chlorophenyl)biguanide] (chlorhexidine, 'Hibitane')

    International Nuclear Information System (INIS)

    Two syntheses of [14C] chlorhexidine ('Hibitane') with the label specifically incorporated in two separate molecular positions are described. Ring labelled chlorhexidine prepared from p-chloro[U-14C]aniline was obtained with a molar specific activity of 27.9 mCi/mmol. Chain labelled material, where the 14C label was incorporated in the 1 and 6 positions of the hexamethylene bridge, was prepared from [1, 6 14C]-adiponitrile, with a molar specific activity of 11.5 mCi/mmol. Several methods of purification are described. (author)

  16. ASK1 (MAP3K5) as a potential therapeutic target in malignant fibrous histiocytomas with 12q14-q15 and 6q23 amplifications.

    Science.gov (United States)

    Chibon, Frédéric; Mariani, Odette; Derré, Josette; Mairal, Aline; Coindre, Jean-Michel; Guillou, Louis; Sastre, Xavier; Pédeutour, Florence; Aurias, Alain

    2004-05-01

    Malignant fibrous histiocytomas (MFHs) are aggressive tumors without any definable line of differentiation. We recently demonstrated that about 20% of them are characterized by high-level amplifications of the 12q14-q15 chromosome region, associated with either 1p32 or 6q23 band amplification. This genetic finding, very similar to that in well-differentiated liposarcomas, strongly suggests that these tumors actually correspond to undifferentiated liposarcomas. It also suggests that the lack of differentiation could be the consequence of amplification of target genes localized in the 1p32 or 6q23 bands. We report here the characterization by array CGH of the 6q23 minimal region of amplification. Our findings demonstrate that amplification and overexpression of ASK1 (MAP3K5), a gene localized in the 6q23 band and encoding a mitogen-activated protein kinase kinase kinase of the JNK-MAPK signaling pathway, could inhibit the adipocytic differentiation process of the tumor cells. Treatment of a cell line with specific inhibitors of ASK1 protein resulted in the bypass of the differentiation block and induction of a strong adipocytic differentiation. These observations indicate that ASK1 is a target for new therapeutic management of these aggressive tumors. PMID:15034865

  17. Determination of the substrate repertoire of ADAMTS2, 3, and 14 significantly broadens their functions and identifies extracellular matrix organization and TGF-β signaling as primary targets.

    Science.gov (United States)

    Bekhouche, Mourad; Leduc, Cedric; Dupont, Laura; Janssen, Lauriane; Delolme, Frederic; Vadon-Le Goff, Sandrine; Smargiasso, Nicolas; Baiwir, Dominique; Mazzucchelli, Gabriel; Zanella-Cleon, Isabelle; Dubail, Johanne; De Pauw, Edwin; Nusgens, Betty; Hulmes, David J S; Moali, Catherine; Colige, Alain

    2016-05-01

    A disintegrin and metalloproteinase with thrombospondin type I motif (ADAMTS)2, 3, and 14 are collectively named procollagen N-proteinases (pNPs) because of their specific ability to cleave the aminopropeptide of fibrillar procollagens. Several reports also indicate that they could be involved in other biological processes, such as blood coagulation, development, and male fertility, but the potential substrates associated with these activities remain unknown. Using the recently described N-terminal amine isotopic labeling of substrate approach, we analyzed the secretomes of human fibroblasts and identified 8, 17, and 22 candidate substrates for ADAMTS2, 3, and 14, respectively. Among these newly identified substrates, many are components of the extracellular matrix and/or proteins related to cell signaling such as latent TGF-β binding protein 1, TGF-β RIII, and dickkopf-related protein 3. Candidate substrates for the 3 ADAMTS have been biochemically validated in different contexts, and the implication of ADAMTS2 in the control of TGF-β activity has been further demonstrated in human fibroblasts. Finally, the cleavage site specificity was assessed showing a clear and unique preference for nonpolar or slightly hydrophobic amino acids. This work shows that the activities of the pNPs extend far beyond the classically reported processing of the aminopropeptide of fibrillar collagens and that they should now be considered as multilevel regulators of matrix deposition and remodeling.-Bekhouche, M., Leduc, C., Dupont, L., Janssen, L., Delolme, F., Vadon-Le Goff, S., Smargiasso, N., Baiwir, D., Mazzucchelli, G., Zanella-Cleon, I., Dubail, J., De Pauw, E., Nusgens, B., Hulmes, D. J. S., Moali, C., Colige, A. Determination of the substrate repertoire of ADAMTS2, 3, and 14 significantly broadens their functions and identifies extracellular matrix organization and TGF-β signaling as primary targets. PMID:26740262

  18. Relocation of carbon from decomposition of {sup 14}C-labelled needle and fine root litter in peat soil

    Energy Technology Data Exchange (ETDEWEB)

    Domish, T.; Laine, J.; Laiho, R. [Helsinki Univ. (Finland). Dept. of Forest Ecology; Finer, L. [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Karsisto, M. [Finnish Forest Research Inst. (Finland). Dept. of Forest Ecology

    1996-12-31

    Drainage of peatlands promotes a shift of biomass and production from the ground vegetation to the trees. Thus, the above-ground (e.g. needles) and below-ground (roots) litter production of trees increases. Fine roots in particular are an important factor in the carbon and nutrient cycle in forest ecosystems. A major part of the annual net primary production of trees may be allocated below ground, the relative proportion being smaller on fertile sites than on less fertile ones. For modelling the carbon balance of drained peatlands, it is important to know the fate of carbon from newly introduced and decomposing litter. Newly added and fertilised tree litter material may be decomposed at a rate different than litter from the ground vegetation. The objectives of this study are to study the pathways of decomposing litter carbon in peat soil and to evaluate the use of the litterbag method in a controlled environment. (9 refs.)

  19. On the isolation of elemental carbon for micro-molar 14C accelerator mass spectrometry; evaluation of alternative isolation procedures, and accuracy assurance using a hybrid isotopic particulate carbon reference material

    Directory of Open Access Journals (Sweden)

    L. A. Currie

    2005-05-01

    Full Text Available The primary objective of the research reported here has been the development of an hybrid reference material (RM to serve as a test of accuracy for elemental carbon (EC isotopic (14C speciation measurements. Such measurements are critically important for the quantitative apportionment of fossil and biomass sources of ''soot'' (EC, the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust, showed a range of results, but since the ''truth'' was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC of measurement validity (Currie et al., 2002. Components of the new Hybrid RM (DiesApple, however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically. NIST SRM 2975 (Forklift Diesel Soot has little or no 14C, and its major compositional component is EC. SRM 1515 (Apple Leaves has the 14C content of biomass-C, and it has little or no EC. Thus, the hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C from SRM 1515 in the EC isolate of the hybrid RM, together with testing for conservation of its dominant soot fraction through the isolation procedure.

  20. 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.

  1. Dosimetric characterization and application of an imaging beam line with a carbon electron target for megavoltage cone beam computed tomography.

    Science.gov (United States)

    Flynn, Ryan T; Hartmann, Julia; Bani-Hashemi, Ali; Nixon, Earl; Alfredo, R; Siochi, C; Pennington, Edward C; Bayouth, John E

    2009-06-01

    Imaging dose from megavoltage cone beam computed tomography (MVCBCT) can be significantly reduced without loss of image quality by using an imaging beam line (IBL), with no flattening filter and a carbon, rather than tungsten, electron target. The IBL produces a greater keV-range x-ray fluence than the treatment beam line (TBL), which results in a more optimal detector response. The IBL imaging dose is not necessarily negligible, however. In this work an IBL was dosimetrically modeled with the Philips Pinnacle3 treatment planning system (TPS), verified experimentally, and applied to clinical cases. The IBL acquisition dose for a 200 degrees gantry rotation was verified in a customized acrylic cylindrical phantom at multiple imaging field sizes with 196 ion chamber measurements. Agreement between the measured and calculated IBL dose was quantified with the 3D gamma index. Representative IBL and TBL imaging dose distributions were calculated for head and neck and prostate patients and included in treatment plans using the imaging dose incorporation (IDI) method. Surface dose was measured for the TBL and IBL for four head and neck cancer patients with MOSFETs. The IBL model, when compared to the percentage depth dose and profile measurements, had 97% passing gamma indices for dosimetric and distance acceptance criteria of 3%, 3 mm, and 100% passed for 5.2%, 5.2 mm. For the ion chamber measurements of phantom image acquisition dose, the IBL model had 93% passing gamma indices for acceptance criteria of 3%, 3 mm, and 100% passed for 4%, 4 mm. Differences between the IBL- and TBL-based IMRT treatment plans created with the IDI method were dosimetrically insignificant for both the prostate and head and neck cases. For IBL and TBL beams with monitor unit values that would result in the delivery of the same dose to the depth of maximum dose under standard calibration conditions, the IBL imaging surface dose was higher than the TBL imaging surface dose by an average of 18

  2. Thick-target neutron, gamma-ray, and radionuclide production for protons below 12 MeV on nickel and carbon beam-stops

    Energy Technology Data Exchange (ETDEWEB)

    Chadwick, M.B.; Young, P.G.; Wilson, W.B.

    1998-03-01

    Nuclear model calculations using the GNASH code are described for protons below 12 MeV incident on nickel and carbon isotopes, for beam stop design in the Los Alamos Accelerator Production of Tritium Low Energy Demonstration Accelerator (LEDA) project. The GNASH calculations apply Hauser-Feshbach and preequilibrium reaction theories and can make use of pre-calculated direct reaction cross sections to low-lying residual nucleus states. From calculated thin target cross sections, thick target 6.7 MeV and 12 MeV proton-induced production of neutrons, gamma rays, and radionuclides are determined. Emission spectra of the secondary neutrons and gamma rays are also determined. The model calculations are validated through comparisons with experimental thin- and thick-target measurements. The results of this work are being utilized as source terms in MCNP analyses for LEDA.

  3. Lithology, fault displacement, and origin of secondary calcium carbonate and opaline silica at Trenches 14 and 14D on the Bow Ridge Fault at Exile Hill, Nye County, Nevada

    International Nuclear Information System (INIS)

    Yucca Mountain, a proposed site for a high-level nuclear-waste repository, is located in southern Nevada, 20 km east of Beatty, and adjacent to the southwest comer of the Nevada Test Site (NTS) (fig. 1). Yucca Mountain is located within the Basin and Range province of the western United States. The climate is semiarid, and the flora is transitional between that of the Mojave Desert to the south and the Great Basin Desert to the north. As part of the evaluation, hydrologic conditions, especially water levels, of Yucca Mountain and vicinity during the Quaternary, and especially the past 20,000 years, are being characterized. In 1982, the US Geological Survey, in cooperation with the US Department of Energy (under interagency agreement DE-A104-78ET44802), excavated twenty-six bulldozer and backhoe trenches in the Yucca Mountain region to evaluate the nature and frequency of Quaternary faulting (Swadley and others, 1984). The trenches were oriented perpendicular to traces of suspected Quaternary faults and across projections of known bedrock faults into Quaternary deposits. Trench 14 exposes the Bow Ridge Fault on the west side of Exile Hill. Although the original purpose of the excavation of trench 14 was to evaluate the nature and frequency of Quaternary faulting on the Bow Ridge Fault, concern arose as to whether or not the nearly vertical calcium carbonate (the term ''carbonate'' in this study refers to calcium carbonate) and opaline silica veins in the fault zone were deposited by ascending waters (ground water). These veins resemble in gross morphology veins commonly formed by hydrothermal processes

  4. Synthesis of carbon C-14 labelled 2-phenyl-4-alpha-alkylaminomethyl-quinolinemethanol: a potential anti-leishmaniasis agent

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.S.T.; Fawwaz, R.A.; Heertum, R.L.van [Columbia Univ., New York, NY (United States). Coll. of Physicians and Surgeons

    1995-07-01

    Using sodium acetate, [1-{sup 14}C] as a starting material, a total of seven steps were required to synthesize the title compound. This involved acylation of ortho-dichlorobenzene to form dichloroacetophenone, [2-{sup 14}C] (I). The 2-phenyl-4-quinoline carboxylic acid, [2-{sup 14}C] (II) was prepared by the Pfitzinger reaction from (1) and dichloroisatin. Compound 11 was converted to the acid chloride (III) by reaction with SOCl{sub 2} in benzene. Grignard condensation reaction of (III) yielded 4-quinolylmethylketone, [2-{sup 14}C] (IV) which was then converted to the bromomethylketone (V). Compound V was reacted with NaBH{sub 4} to form the ethylene oxide (VI). Alkylation of the oxide yielded the title compound (VII). The overall radiochemical yield was 10.1% and the specific activity was 3.0 mCi/mmol, with a radiochemical purity of >99.5%. (author).

  5. The applicability of C-14 measurements in the soil gas for the assessment of leakage out of underground carbon dioxide reservoirs

    Directory of Open Access Journals (Sweden)

    Chałupnik Stanisław

    2014-03-01

    Full Text Available Poland, due to the ratification of the Kioto Protocol, is obliged to diminish the emission of greenhouse gases. One of the possible solutions of this problem is CO2 sequestration (CCS - carbon capture and storage. Such an option is a priority in the European Union. On the other hand, CO2 sequestration may be potentially risky in the case of gas leakage from underground reservoirs. The most dangerous event may be a sudden release of the gas onto the surface. Therefore, it is very important to know if there is any escape of CO2 from underground gas reservoirs, created as a result of sequestration. Such information is crucial to ensure safety of the population in areas located above geological reservoirs. It is possible to assess the origin of carbon dioxide, if the measurement of radiocarbon 14C concentration in this gas is done. If CO2 contains no 14C, it means, that the origin of the gas is either geological or the gas has been produced as a result of combustion of fossil fuels, like coal. A lot of efforts are focused on the development of monitoring methods to ensure safety of CO2 sequestration in geological formations. A radiometric method has been tested for such a purpose. The main goal of the investigations was to check the application possibility of such a method. The technique is based on the liquid scintillation counting of samples. The gas sample is at first bubbled through the carbon dioxide adsorbent, afterwards the adsorbent is mixed with a dedicated cocktail and measured in a low-background liquid scintillation spectrometer Quantulus. The described method enables measurements of 14C in mine and soil gas samples.

  6. Carbon-14 in tree rings and other terrestrial samples in the vicinity of Ignalina Nuclear Power Plant, Lithuania

    Energy Technology Data Exchange (ETDEWEB)

    Mazeika, Jonas [Radioisotope Research Laboratory, Institute of Geology and Geography, T. Sevcenkos 13, LT-03223 Vilnius (Lithuania)], E-mail: mazeika@geo.lt; Petrosius, Rimantas [Radioisotope Research Laboratory, Institute of Geology and Geography, T. Sevcenkos 13, LT-03223 Vilnius (Lithuania); Pukiene, Rutile [Dendroclimatology and Radiometrics Group, Vytautas Magnus University, Z.E. Zilibero 6, LT-46324 Kaunas (Lithuania)], E-mail: r.pukiene@gmf.vdu.lt

    2008-02-15

    The results of {sup 14}C measurements in the annual tree rings from the Ignalina Nuclear Power Plant (INPP) surroundings, Lithuania, for the period of its operation from 1984 to 2002 are presented. The terrestrial samples, mainly moss and related soil, are studied in places as well. The tree rings have shown slightly enhanced {sup 14}C activity due to operation of the nuclear power plant. The maximal calculated normalized {sup 14}C release of 11 TBq GW{sub e}{sup -1} year{sup -1} and the maximal effective dose of 2.0 x 10{sup -3} mSv year{sup -1} resulting from the {sup 14}C were estimated for 1999. For other years of INPP operation these values are lower. The excess of {sup 14}C specific activity measured in the moss and soil samples from moss-covered sites near the nuclear power plant (up to 0.5 km) showed highly elevated {sup 14}C contents (up to 813 pMC), probably indicating releases of particulate material.

  7. Photoperiodic effects on short-pulse 14C assimilation and overall carbon and nitrogen allocation patterns in contrasting quinoa cultivars

    DEFF Research Database (Denmark)

    Bendevis, Mira Arpe; Sun, Yujie; Rosenqvist, Eva;

    2014-01-01

    photoperiod neutral cv. 'Titicaca' were studied under short (10h) and long (17.5h) days, with respect to C and N distribution as well as partitioning of newly assimilated C to plant organs. An extended photoperiod resulted in 14C decreasingly being allocated to stem growth and lower leaves in 'Titicaca', but...... an immediate increase in carbon allocation to upper leaves, and over time to the reproductive structures, resulting in a more than 50% increase in final yield. Collectively the results indicate that even though the photoperiod sensitive cultivar flowered under long photoperiod it did not develop...

  8. Influence of atmospheric 14CO2 on determination of the ratio of biogenic carbon to fossil one in exhaust gases using accelerator mass spectrometry. Experimental evaluation for industrial flue gases

    International Nuclear Information System (INIS)

    The influence of atmospheric 14CO2 was evaluated on the determination of biogenic carbon ratios in industrial flue gases using accelerated mass spectrometry(AMS). Bioethanol, n-hexane, and their mixtures were combusted with a four-stroke engine, and 14CO2 in exhaust gases was analyzed by AMS. The experimental biogenic carbon ratio determined by ASTM D6866 method was 1.2 times higher than the theoretical value of mixed fuel containing 3.18% biogenic carbons. In general, the influence of atmospheric 14CO2 taken in combustion gases is neglected. It seems that the error cannot be neglected under international trading of emission allowances, where a large amount of carbons in the fuel were evaluated. The experimental value became to be the theoretical value by subtracting the amount of atmospheric 14C from that of the samples. As the contents of biofuel increased, the experimental biogenic carbon ratios reached the theoretical values and the influence of atmospheric 14CO2 decreased. We recommend that the influence of atmospheric 14CO2 should be corrected when fuel samples contain low amounts of 14C. (author)

  9. Assessment of a ground water flow model of the Bangkok Basin, Thailand, using carbon-14-based ages and paleohydrology

    Science.gov (United States)

    Sanford, W.E.; Buapeng, S.

    1996-01-01

    A study was undertaken to understand the groundwater flow conditions in the Bangkok Basin, Thailand, by comparing 14C-based and simulated groundwater ages. 14C measurements were made on about 50 water samples taken from wells throughout the basin. Simulated ages were obtained using 1) backward-pathline tracking based on the well locations, and 2) results from a three-dimensional groundwater flow model. Comparisons of ages at these locations reveal a large difference between 14C-based ages and ages predicted by the steady-state groundwater flow model. Mainly, 14C and 13C analyses indicate that groundwater in the Bangkok area is about 20,000 years old, whereas steady-state flow and transport simulations imply that groundwater in the Bangkok area is 50,000-100,000 years old. One potential reason for the discrepancy between simulated and 14C-based ages is the assumption in the model of steady-state flow. Groundwater velocities were probably greater in the region before about 10,000 years ago, during the last glacial maximum, because of the lower position of sea level and the absence of the surficial Bangkok Clay. Paleoflow conditions were estimated and then incorporated into a second set of simulations. The new assumption was that current steady-state flow conditions existed for the last 8,000 years but were preceded by steady-state conditions representative of flow during the last glacial maximum. This "transient" paleohydrologic simulation yielded a mean simulated age that more closely agrees with the mean 14C-based age, especially if the 14C-based age is corrected for diffusion into clay layers. Although the uncertainties in both the simulated and 14C-based ages are nontrivial, the magnitude of the improved match in the mean age using a paleohydrologic simulation instead of a steady-state simulation suggests that flow conditions in the basin have changed significantly over the last 10,000-20,000 years. Given that the valid age range of 14C-dating methods and the

  10. Understanding the Mechanisms Enabling an Ultra-high Efficiency Moving Wire Interface for Real-time Carbon 14 Accelerator Mass Spectrometry Quantitation of Samples Suspended in Solvent

    Science.gov (United States)

    Thomas, Avraham Thaler

    Carbon 14 (14C) quantitation by accelerator mass spectrometry (AMS) is a powerfully sensitive and uniquely quantitative tool for tracking labeled carbonaceous molecules in biological systems. This is due to 14C's low natural abundance of 1 ppt, the nominal difference in biological activity between an unlabeled and a 14C-labeled molecule, and the ability of AMS to measure isotopic ratios independently of a sample's other characteristics. To make AMS more broadly accessible, a moving wire interface for real-time coupling of high pressure liquid chromatography (HPLC) to AMS and high throughput AMS quantitation of minute single samples has been developed. Prior to this work, samples needed to be converted to solid carbon before measurement. This conversion process has many steps and requires that the sample size be large enough to allow precise handling of the resulting graphite. These factors make the process susceptible to error and time consuming, as well as requiring 0.5 ug of carbon. Samples which do not contain enough carbon, such as HPLC fractions, must be bulked up. This adds background and increases effort. The moving wire interface overcomes these limitations by automating sample processing. Samples placed on the wire are transported through a solvent removal stage followed by a combustion stage after which the combustion products are directed to a gas accepting ion source. The ion source converts the carbon from the CO2 combustion product into C ions, from which an isotopic ratio can be determined by AMS. Although moving wire interfaces have been implemented for various tasks since 1964, the efficiency of these systems at transferring fluid from an HPLC to the wire was only 3%, the efficiency of transferring combustion products from the combustion oven to ion source was only 30%, the flow and composition of the carrier gas from the combustion oven to the ion source needed to be optimized for coupling to an AMS gas accepting ion source and the drying ovens

  11. Carbon cycle dynamics and solar activity embedded in a high-resolution 14C speleothem record from Belize, Central America

    Science.gov (United States)

    Lechleitner, Franziska A.; Breitenbach, Sebastian F. M.; McIntyre, Cameron; Asmerom, Yemane; Prufer, Keith M.; Polyak, Victor; Culleton, Brendan J.; Kennett, Douglas J.; Eglinton, Timothy I.; Baldini, James U. L.

    2015-04-01

    Speleothem 14C has recently emerged as a potentially powerful proxy for climate reconstruction. Several studies have highlighted the link between karst hydrology and speleothem 14C content, and a number of possible causes for this relationship have been proposed, such as dripwater flow dynamics in the karst and changes in soil organic matter (SOM) turnover time (e.g. Griffiths et al., 2012). Here we present a high resolution 14C record for a stalagmite (YOK-I) from Yok Balum cave in southern Belize, Central America. YOK-I grew continuously over the last 2000 years, and has been dated very precisely with the U-Th method (40 dates, mean uncertainty ventilation and hydrologic resilience to seismic activity, Journal of Cave and Karst Studies

  12. 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

  13. Autoradiographic study on the incorporation of carbon-14 labeled formate and adenine into nucleic acid in blood-forming cells

    International Nuclear Information System (INIS)

    The incorporation of [14C]formate and [8-14C]adenine into nucleic acid in blood-forming cells was studied by the autoradiographic technique. The isotopic markers were injected subcutaneously into young rats weighting from 100 to 150 g three times every 24 hours and the animals were examined 3 hours after the last injection. In the case of [14C]formate injection, erythroblasts exhibited extremely strong labeling in contrast to weaker labeling of other blood-forming cells. In the case of [14C]adenine administration, on the other hand, immature cells of the granuclocytic series as well as immature reticulum cells (proliferating cells of reticular tissue) were much more heavily labeled than were other blood-forming cells, particularly the erythroblasts which revealed weak or no labeling. By digestion or extraction of DNA, RNA or both from cells with DNase, RNase or hot 10% perchloric acid treatment, respectively, it was confirmed that the observed heavy labeling of any type of cells with either [14C]formate or [14C]adenine was due chiefly to incorporation of the radioactive materials into nuclear DNA. The present results are discussed together with the findings of earlier studies on lymphoid cells which indicate that, in certain cell types, the patterns of [3H]deoxycytidine labeling differ considerably from the corresponding patterns of [3H]deoxycytidine labeling. The present and earlier findings provide evidence to substantiate that, among blood-forming cells, there are considerable variations in the labeling patterns of nuclear DNA depending on differences in the radioactive DNA precursors used as well as in the cell types. (author)

  14. Comment on: Comment on ''Mysterious abrupt carbon-14 increase in coral contributed by a come'' Yi Liu et al

    CERN Document Server

    Melott, Adrian L

    2014-01-01

    Unfortunately, Liu et al. contains a number of errors and omissions which compromise its conclusions. These have to do with the amount of 14C which is necessary to deposit in the atmosphere in order to see a perturbation like that in 774 AD, and the ability of a comet to do so.

  15. Carbon isotope (δ13C) excursions suggest times of major methane release during the last 14 ka in Fram Strait, the deep-water gateway to the Arctic

    Science.gov (United States)

    Consolaro, C.; Rasmussen, T. L.; Panieri, G.; Mienert, J.; Bünz, S.; Sztybor, K.

    2014-10-01

    We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (∼80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dating reveals a detailed chronology for the last 14 ka BP. The δ13C record measured on the benthic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values, as low as -4.37‰ in the Bølling-Allerød interstadials and as low as -3.41‰ in the early Holocene. After cleaning procedure designed to remove all authigenic carbonate coatings on benthic foraminiferal tests, the 13C values are still negative (as low as -2.75‰). We have interpreted these negative carbon isotope excursions (CIEs) to record past methane release events, resulting from the incorporation of 13C-depleted carbon from methane emissions into the benthic foraminiferal shells. The CIEs during the Bølling-Allerød interstadials and the early Holocene relate to periods of ocean warming, sea level rise and increased concentrations of methane (CH4) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

  16. 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.

  17. Carboxylic acid functionalization prevents the translocation of multi-walled carbon nanotubes at predicted environmentally relevant concentrations into targeted organs of nematode Caenorhabditis elegans

    Science.gov (United States)

    Nouara, Abdelli; Wu, Qiuli; Li, Yinxia; Tang, Meng; Wang, Haifang; Zhao, Yuliang; Wang, Dayong

    2013-06-01

    Carboxyl (-COOH) surface modified multi-walled carbon nanotubes (MWCNTs-COOH) can be used for targeted delivery of drugs and imaging. However, whether MWCNTs-COOH at environmentally relevant concentrations exert certain toxic effects on multicellular organisms and the underlying mechanisms are still largely unclear. In the present study, we applied the nematode Caenorhabditis elegans to evaluate the properties of MWCNTs-COOH at environmentally relevant concentrations by comparing the effects of MWCNTs and MWCNTs-COOH exposure on C. elegans from L1-larvae to adult at concentrations of 0.001-1000 μg L-1. Exposure to MWCNTs could potentially damage the intestine (primary targeted organ) at concentrations greater than 0.1 μg L-1 and functions of neurons and reproductive organ (secondary targeted organs) at concentrations greater than 0.001 μg L-1. Carboxyl modification prevented the toxicity of MWCNTs on the primary and the secondary targeted organs at concentrations less than 100 μg L-1, suggesting that carboxyl modification can effectively prevent the adverse effects of MWCNTs at environmentally relevant concentrations. After exposure, MWCNTs-COOH (1 mg L-1) were translocated into the spermatheca and embryos in the body through the primary targeted organs. However, MWCNTs-COOH (10 μg L-1) were not observed in spermatheca and embryos in the body of nematodes. Moreover, relatively high concentrations of MWCNTs-COOH exposed nematodes might have a hyper-permeable intestinal barrier, whereas MWCNTs-COOH at environmentally relevant concentrations effectively sustained the normally permeable state for the intestinal barrier. Therefore, we elucidated the cellular basis of carboxyl modification to prevent toxicity of MWCNTs at environmentally relevant concentrations. Our data highlights the key role of biological barriers in the primary targeted organs to block toxicity formation from MWCNTs, which will be useful for the design of effective prevention strategies against

  18. A General Method for the Rapid Determination of Carbon-14- and Hydrogen-3-Labelled Substances by Gas Chromatography

    International Nuclear Information System (INIS)

    A method is described for the determination of 14C- and 3H- labelled substances by gas chromatography using different size flow counters. The method of cracking substances in a current of hydrogen gas is especially suitable for 3H-labelled compounds because it is free from the disadvantages encountered when the substances are first oxidized and the water formed subsequently converted. The general applicability of this method is shown for different classes of compounds. The analysis is independent of the chemical composition of the compound. By using a part oi the apparatus very rapid analyses of vaporizable 14C- and apparently all 3H-labelled substances can be made by direct injection into the reaction chamber. The apparatus can also be used for the oxidation procedure. (author)

  19. Carbon-14-ochratoxin A distribution in the Japanese quail (Coturnix coturnix japonica) monitored by whole body autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, R.; Appelgren, L.E.; Hagelberg, S.; Hult, K.

    1988-05-01

    Tissue distribution of the nephrotoxic mycotoxin ochratoxin A was characterized in laying Japanese quail by whole body autoradiography and scintillation counting using /sup 14/C-labelled toxin. Periodically for 8 days after one intravenous injection of 14 microCi/bird, corresponding to 70 ng/g body weight, birds were killed, frozen, and sagittal sections of the whole body were placed on X-ray film. In general, the ochratoxin disappeared from the avian body rapidly. Specific retention of radioactivity was seen as a ring-like distribution in yolks and growing follicles. After sectioning, organs and intestinal contents were removed from carcasses in a frozen condition, homogenized, extracted, chromatographed, and the radioactivity in fractions was measured by scintillation spectroscopy. High concentrations of ochratoxin A were found in gastric intestinal contents, probably originating from toxin excreted in the bile.

  20. The carbon-14 spike in the 8th century was not caused by a cometary impact on Earth

    Science.gov (United States)

    Usoskin, Ilya G.; Kovaltsov, Gennady A.

    2015-11-01

    A mysterious increase of radiocarbon 14 C ca. 775 AD in the Earth's atmosphere has been recently found by Miyake et al. (Miyake, F., Nagaya, K., Masuda, K., Nakamura, T. [2012]. Nature, 486, 240). A possible source of this event has been discussed widely, the most likely being an extreme solar energetic particle event. A new exotic hypothesis has been presented recently by Liu et al. (Liu, Y. [2014]. Sci. Rep., 4, 3728) who proposed that the event was caused by a cometary impact on Earth bringing additional 14 C to the atmosphere. Here we calculated a realistic mass and size of such a comet to show that it would have been huge (≈100 km across and 1017-1020 g of mass) and would have produced a disastrous geological/biological impact on Earth. The absence of an evidence for such a dramatic event makes this hypothesis invalid.

  1. 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)

  2. Total and Partial Fragmentation Cross-Section of 500 MeV/nucleon Carbon Ions on Different Target Materials

    CERN Document Server

    Alpat, Behcet; Blasko, Sandor; Caraffini, Diego; Di Capua, Francesco; Postolache, Vasile; Saltanocchi, Giorgio; Menichelli, Mauro; Desorgher, Laurent; Durante, Marco; Pleskac, Radek; La Tessa, Chiara

    2014-01-01

    By using an experimental setup based on thin and thick double-sided microstrip silicon detectors, it has been possible to identify the fragmentation products due to the interaction of very high energy primary ions on different targets. Here we report total and partial cross-sections measured at GSI (Gesellschaft fur Schwerionenforschung), Darmstadt, for 500 MeV/n energy $^{12}C$ beam incident on water (in flasks), polyethylene, lucite, silicon carbide, graphite, aluminium, copper, iron, tin, tantalum and lead targets. The results are compared to the predictions of GEANT4 (v4.9.4) and FLUKA (v11.2) Monte Carlo simulation programs.

  3. Ammonium carbonate loss rates from lures differentially affect trap captures of Rhagoletis indifferens (Diptera: Tephritidae) and non-target flies

    Science.gov (United States)

    Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is a pest of cherry (Prunus spp.) in western North America that can be monitored using traps baited with ammonia. However, ammonia-based attractants also attract non-target Diptera that clutter traps. Here, the hypothe...

  4. Biomarker and carbon isotope constraints (δ13C, Δ14C) on sources and cycling of particulate organic matter discharged by large Siberian rivers draining permafrost areas

    International Nuclear Information System (INIS)

    Circumpolar permafrost soils store about half of the global soil organic carbon pool. These huge amounts of organic matter (OM) could accumulate due to low temperatures and water saturated soil conditions over the course of millennia. Currently most of this OM remains frozen and therefore does not take part in the active carbon cycle, making permafrost soils a globally important carbon sink. Over the last decades mean annual air temperatures in the Arctic increased stronger than the global mean and this trend is projected to continue. As a result the permafrost carbon pool is under climate pressure possibly creating a positive climate feedback due to the thaw-induced release of greenhouse gases to the atmosphere. Arctic warming will lead to increased annual permafrost thaw depths and Arctic river runoff likely resulting in enhanced mobilization and export of old, previously frozen soil-derived OM. Consequently, the great arctic rivers play an important role in global biogeochemical cycles by connecting the large permafrost carbon pool of their hinterlands with the arctic shelf seas and the Arctic Ocean. The first part of this thesis deals with particulate organic matter (POM) from the Lena Delta and adjacent Buor Khaya Bay. The Lena River in central Siberia is one of the major pathways translocating terrestrial OM from its southernmost reaches near Lake Baikal to the coastal zone of the Laptev Sea. The permafrost soils from the Lena catchment area store huge amounts of pre-aged OM, which is expected to be remobilized due to climate warming. To characterize the composition and vegetation sources of OM discharged by the Lena River, the lignin phenol and carbon isotopic composition (δ13C and Δ14C) in total suspended matter (TSM) from surface waters, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex) were analyzed. The lignin compositions of these samples are consistent

  5. Investigation of HCCI Combustion of Diethyl Ether and Ethanol Mixtures Using Carbon 14 Tracing and Numerical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mack, J H; Dibble, R W; Buchholz, B A; Flowers, D L

    2004-01-16

    Despite the rapid combustion typically experienced in Homogeneous Charge Compression Ignition (HCCI), components in fuel mixtures do not ignite in unison or burn equally. In our experiments and modeling of blends of diethyl ether (DEE) and ethanol (EtOH), the DEE led combustion and proceeded further toward completion, as indicated by {sup 14}C isotope tracing. A numerical model of HCCI combustion of DEE and EtOH mixtures supports the isotopic findings. Although both approaches lacked information on incompletely combusted intermediates plentiful in HCCI emissions, the numerical model and {sup 14}C tracing data agreed within the limitations of the single zone model. Despite the fact that DEE is more reactive than EtOH in HCCI engines, they are sufficiently similar that we did not observe a large elongation of energy release or significant reduction in inlet temperature required for light-off, both desired effects for the combustion event. This finding suggests that, in general, HCCI combustion of fuel blends may have preferential combustion of some of the blend components.

  6. Constraints on emissions of carbon monoxide, methane, and a suite of hydrocarbons in the Colorado Front Range using observations of 14CO2

    Directory of Open Access Journals (Sweden)

    P. P. Tans

    2013-01-01

    Full Text Available Atmospheric radiocarbon (14CO represents an important observational constraint on emissions of fossil-fuel derived carbon into the atmosphere due to the absence of 14CO in fossil fuel reservoirs. The high sensitivity and precision that accelerator mass spectrometry (AMS affords in atmospheric 14CO analysis has greatly increased the potential for using such measurements to evaluate bottom-up emissions inventories of fossil fuel CO2 (CO2ff, as well as those for other co-emitted species. Here we use observations of 14CO2 and a series of hydrocarbons and combustion tracers from discrete air samples collected between June 2009 and September 2010 at the National Oceanic and Atmospheric Administration Boulder Atmospheric Observatory (BAO; Lat: 40.050° N, Lon: 105.004° W to derive emission ratios of each species to CO2ff. From these emission ratios, we estimate emissions of these species by using the Vulcan CO2ff high resolution data product as a reference. The species considered in this analysis are carbon monoxide (CO, methane (CH4, acetylene (C2H2, benzene (C6H6, and C3–C5 alkanes. Comparisons of top-down emissions estimates are made to existing inventories of these species for Denver and adjacent counties, as well as to previous efforts to estimate emissions from atmospheric observations over the same area. We find that CO is overestimated in the 2008 National Emissions Inventory (NEI, 2008 by a factor of ~2. A close evaluation of the inventory suggests that the ratio of CO emitted per unit fuel burned from on-road gasoline vehicles is likely over-estimated by a factor of 2.5. The results also suggest that while the oil and gas sector is the largest contributor to the CH4 signal in air arriving from the north and east, it is very likely that other sources, including agricultural sources, contribute to this signal and must be accounted for when attributing these signals to oil and gas industry activity from a top-down perspective. Our results are

  7. The 14C as tracer in the carbon flow assimilated by the plants (maize, sugar cane, bean) and it liberation to the soil

    International Nuclear Information System (INIS)

    The flow of carbon in three different crops, maize, beans and sugar cane was studied by use of 14V. The plants were exposed to an atmosphere with a constant concentration of the tracer for 12 hours in a biosynthesis chamber. The detection of the isotope permitted the distribution and concentration of the photosynthetates in the various organs of the plants and the losses by liberation to the soil whether by root respiration or rhizodeposition to be followed. The technique of marking metabolites through photosynthesis and their detection in the various plant organs is well known and is employed despite the requirement for hight sophisticated apparatus. On the other hand the quantification of the plant-soil-microorganism interchanges presents great difficulties being dynamic processes, showing the necessity of more detailed studies. (author)

  8. Determination of Each Province's Carbon Dioxide Reduction Target Based on Embodied Carbon Dioxide Emissions%基于隐含碳排放的碳减排目标研究

    Institute of Scientific and Technical Information of China (English)

    张增凯; 郭菊娥; 安尼瓦尔·阿木提

    2011-01-01

    中国政府以2005年为基年提出了碳减排指标,确定各省碳减排基数对于明确各省碳减排责任具有重要意义.本文结合“十一五”期间节能指标分解过程中存在的问题,分析了省际贸易中隐含的碳排放对于确定各省碳减排基数的影响,并分别基于生产者负责原则和消费者负责原则计算了“十二五”期间各省碳减排基数.计算结果表明:①将工业部门拆分为23个部门能够更加充分反映省际贸易结构差异对于隐含碳排放计算的影响;②省际贸易中隐含碳排放不仅在各省间有较大差异而且呈现出从中西部地区调往东部地区的整体转移方向;③不同原则下各省碳减排基数计算结果存在较大差异,消费者负责原则更加真实地反映了各地区实际减排责任,避免了部分省份通过省际调进代替本省生产的方式实现碳减排目标.%Measuring each province's carbon dioxide emissions is of great significance for the carbon reduction target, announced by Chinese Central Government, with 2005 as the base year. This paper firstly analyzes the existing problems of the energy conservation during the Eleventh Five Year Plan period and then studies the influence of embodied carbon dioxide emissions on the calculation of each province' s carbon emissions basis. Finally, each province' s carbon dioxide emissions of the base year are calculated based on two principles: the producer responsibility principle and the consumer responsibility principle. Several crucial conclusions are drawn as follows. First, dividing the industrial sector into 23 sectors adequately reflects the influence of the structural difference in inter-provincial trade on the calculation of the embodied carbon dioxide emissions. Second, the provincial differences of embodied carbon dioxide emissions are obvious. The transfer direction of embodied carbon dioxide emissions is from the central and western regions to the eastern

  9. Cost-benefit analyses for the retention of tritium, carbon 14 and krypton 85 from plants reprocessing LWR fuel elements

    International Nuclear Information System (INIS)

    ICRP's new system for the limitation of permissible doses is applied for the determination of optimum emission rates from reprocessing plants. Equivalent doses and collective doses are calculated using radioecological methods. Economy-oriented and sociological methods were used to estimate the damage to health and life expressed in monetary units (α-value equals DM 200.-/manxrem). A cost-benefit analysis was done considering retention cost, collective doses and α-value, and the results were different from those supplied by the nowadays customary retention criteria, the latter being based on the limitation of individual doses rather than collective doses. The results are surprising because for the Gorleben facility retention of krypton-85 and tritium is planned, C-14 being left out of consideration so far. (DG)

  10. Report of Carbon-14 Dates (28)%放射性碳素测定年代报告(二八)

    Institute of Scientific and Technical Information of China (English)

    中国社会科学院考古研究所考古科技实验研究中心碳十四实验室

    2002-01-01

    The present report publishes the chronological data of specimens tested by the 14C Laboratory of the Archaeological Science and Techniques Experiment and Research Center, IA, CASS, in cooperation with the Institute of Biophysics, CAS, from 1998 to 2001. These specimens, totaling 230 pieces, come from the following 11 archaeological sites: Erlitou in Yanshi County, Henan (28); Nanzhai in Yichuan County, Henan (10) ; Nianzipo in Changwu County, Shaanxi (21) ; Shang city in Yanshi, Henan (25) ; Shang city in Zhengzhou City, Henan (20+10) ; Xiaoshuangqiao in Zhengzhou City, Henan (5); Yinxu in Anyang City, Henan (43); Zhangjiapo in Chang' an City, Shaanxi (9+12); Mawangcun in Chang'an City, Shaanxi (10) ; Liulihe in Fangshan County, Beijing (25+6) ; and Jin Marquis tomb at Beizhaocun in Quwo County, Shanxi (6).

  11. A competitive strategy coupled with endonuclease-assisted target recycling for DNA detection using silver-nanoparticle-tagged carbon nanospheres as labels.

    Science.gov (United States)

    Zhu, Zhu; Gao, Fenglei; Lei, Jianping; Dong, Haifeng; Ju, Huangxian

    2012-10-22

    A simple competitive strategy was designed for the sensitive detection of sequence-specific DNA by combining endonuclease-assisted target recycling and electrochemical stripping analysis of silver nanoparticles (AgNPs). The AgNP-tagged carbon nanospheres were synthesized by means of in situ reduction of Ag(+) adsorbed onto a negatively charged polyelectrolyte layer and functionalized with streptavidin for binding biotin-labeled DNA strands. The labeled strand was captured on the DNA sensor surface by competitive hybridization of biotinated primer 1 and its cleaved product. The cleaved product could be amplified in homogeneous solution by endonuclease-assisted target recycling with a Y-shaped junction DNA structure, thus leading to the correlation of the stripping signal to the target concentration. The functionalized nanosphere was characterized with X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The proposed method showed a linear range from 0.1 to 1000 fM with a limit of detection of 0.066 fM (3σ) and good selectivity for base discrimination. The designed strategy provided a sensitive tool for DNA analysis and could be widely applied in bioanalysis and biomedicine.

  12. Near Surface Leakage Monitoring for the Verification and Accounting of Geologic Carbon Sequestration Using a Field Ready {sup 14}C Isotopic Analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Marino, Bruno

    2014-04-14

    Results for the development of a field ready multi-isotopic analyzer for {sup 12}CO{sub 2}, {sup 13}CO{sub 2} and {sup 14}CO{sub 2} and applications for carbon capture and storage (CCS) containment performance are described. A design goal of the field platform was to provide isotopic data with a high data rate, a standardized reference baseline and acceptable precision (e.g., ~ ±50 per mil D{sup 14}CO{sub 2}) for detection and quantification of fossil-fuel CO{sub 2} CCS leakage scenarios. The instrument platform was not designed to replace high precision accelerator mass spectrometry. An additional goal was to combine project scale isotopic data and associated fluxes with unique financial instruments linking CCS containment performance to a publicly traded security providing project revenue to stakeholders. While the primary goals of the project were attained additional work is needed for the instrument platform and deployment within a full scale CCS site that was not available during the project timeframe.

  13. 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)

  14. TRIM14 inhibits hepatitis C virus infection by SPRY domain-dependent targeted degradation of the viral NS5A protein

    Science.gov (United States)

    Wang, Shanshan; Chen, Yongzhi; Li, Chunfeng; Wu, Yaoxing; Guo, Lei; Peng, Changwei; Huang, Yueping; Cheng, Genhong; Qin, F. Xiao-Feng

    2016-01-01

    Tripartite motif 14 (TRIM14) was reported to function as a mitochondrial signaling adaptor in mediating innate immune responses. However, the involvement of TRIM14 in host defense against viral infection and molecular mechanisms remain unclear. Here, we demonstrated that enforced expression of TRIM14 could potently inhibit the infection and replication of HCV in hepatocytes, whereas TRIM14 knockout cells became more susceptible to HCV infection. Interestingly, further experiments revealed that such anti-HCV activity was independent of activating the NF-κB or interferon pathways but required the C-terminal SPRY domain of no signaling capacity. In searching for mechanisms how TRIM14 exerts its antiviral function we found that TRIM14 interacted with HCV encoded non-structural protein NS5A and could strongly induce its degradation dependent on the NS5A1 subdomain. Interestingly extensive domain mapping analyses revealed that NS5A degradation was mediated by the highly conserved SPRY domain of TRIM14, which might involve the K48 ubiquitination pathway. Collectively, our work uncovered a new mechanism responsible for host defense against HCV infection, and could potentially aid the development of novel anti-HCV therapeutics. PMID:27578425

  15. Accuracy of a rapid 10-minute carbon-14 urea breath test for the diagnosis of Helicobacter pylori-associated peptic ulcer disease

    International Nuclear Information System (INIS)

    Urease in the human gastric mucosa is a marker for infection with Helicobacter pylori (HP), an organism which is associated with peptic ulcer disease. To detect gastric urease, we examined 184 patients (144 males, 40 females; mean age: 49.8±15.6 years) with suspected peptic ulcer disease. Fasting patients were given orally 5 μCi of carbon-14 labelled urea. For each patient only one breath sample was collected in hyamine at 10 min. The amount of 14C collected at 10 min was expressed as follows: [(DPM/mmol CO2 collected)/(DPM administered)]x100xbody weight (kg). The presence of HP colonization was determined by examination of multiple endoscopic prepyloric antral biopsy specimens subjected to culture or a rapid urease test. For the purpose of this study, HP-positive patients were defined as those with characteristic bacteria as indicated by a positive result of either the culture or the rapid urease test; HP-negative patients were defined as those with negative findings on both the culture and the rapid urease test. Of the 184 cases, 99 (53.8%) were positive for HP infection, and 85 (46.2%), negative. The sensitivity and specificity of the rapid 10 min 14C-urea breath test for the diagnosis of HP-associated peptic ulcer disease were evaluated by a receiver operating characteristic (ROC) curve with a variable cut-off value from 1.5 to 4.5. When a cut-off value of 1.5 was selected, the sensitivity was 100% and the specificity, 83.5%; when a cut-off value of 4.5 was selected, the sensitivity was 54.5% and the specificity, 97.6%. (orig.)

  16. A Model-based Interpretation of Low-frequency Changes in the Carbon Cycle during the Last 120,000 years and its Implications for the Reconstruction of Atmospheric (delta) 14-C

    Science.gov (United States)

    Koehler, Peter; Muscheler, Raimund; Fischer, Hubertus

    2006-01-01

    A main caveat in the interpretation of observed changes in atmospheric (Delta)C-l4 during the last 50,000 years is the unknown variability of the carbon cycle, which together with changes in the C-14 production rates determines the C-14 dynamics. A plausible scenario explaining glacial/interglacial dynamics seen in atmospheric CO2 and (delta)C-13 was proposed recently (Kohler et al., 2005a). A similar approach that expands its interpretation to the C-14 cycle is an important step toward a deeper understanding of (Delta)C-14 variability. This approach is based on an ocean/atmosphere/biosphere box model of the global carbon cycle (BICYCLE) to reproduce low-frequency changes in atmospheric CO2 as seen in Antarctic ice cores. The model is forced forward in time by various paleoclimatic records derived from ice and sediment cores. The simulation results of our proposed scenario match a compiled CO2 record from various ice cores during the last 120,000 years with high accuracy (r(sup 2) = 0.89). We analyze scenarios with different C-14 production rates, which are either constant or based on Be-10 measured in Greenland ice cores or the recent high-resolution geomagnetic field reconstruction GLOPIS-75 and compare them with the available (Delta)C-14 data covering the last 50,000 years. Our results suggest that during the last glacial cycle in general less than 110%0o f the increased atmospheric (Delta)C-14 is based on variations in the carbon cycle, while the largest part (5/6) of the variations has to be explained by other factors. Glacial atmospheric (Delta)C-14 larger than 700% cannot not be explained within our framework, neither through carbon cycle-based changes nor through variable C-14 production. Superimposed on these general trends might lie positive anomalies in atmospheric (Delta)C-14 of approx. 50% caused by millennial-scale variability of the northern deep water production during Heinrich events and Dansgaard/Oeschger climate fluctuations. According to our

  17. Platinum-coordinated graphitic carbon nitride nanosheet used for targeted inhibition of amyloid β-peptide aggregation

    Institute of Scientific and Technical Information of China (English)

    Meng Li; Yijia Guan; Zhaowei Chen; Nan Gao; Jinsong Ren; Kai Dong; Xiaogang Qu

    2016-01-01

    Amyloid β-peptide (Aβ) aggregation is a critical step in the pathogenesis of Alzheimer's disease (AD).Inhibition of Aβ production,dissolution of existing aggregates and clearance of Aβ represent valid therapeutic strategies against AD.Herein,a novel platinum(Ⅱ)-coordinated graphitic carbon nitride (g-C3N4)nanosheet (g-C3N4@Pt) has been designed to covalently bind to Aβ and modulate the peptide's aggregation and toxicity.Furthermore,g-C3N4@Pt nanosheets possess high photocatalytic activity and can oxygenate Aβ upon visible light irradiation,remarkably attenuating both the aggregation potency and neurotoxidty of Aβ.Due to its ability to cross the blood-brain barrier (BBB) and its good biocompatibility,g-C3N4@Pt nanosheet is a promising inhibitor of Aβ aggregation.This study may serve as a model for the engineering of novel multifunctional nanomaterials used for the treatment of AD.

  18. Labeled plasma metabolites of L-methyl-hydrogen-3-methionine and L-methyl-carbon-14-methionine in the dog

    International Nuclear Information System (INIS)

    The validity of the mathematical models that attempt to describe positron emission tomography (PET) images produced with [11CH3] methionine in terms of rates of local cerebral protein synthesis has yet to be established. A major objection to current models is that the use of methionine labeled at the methyl position results in the dispersal of the label among various methyl-accepting compounds that appear in the plasma and may then enter the brain. One approach to overcoming this problem has been the use of ''standard'' corrections for the activity contributed to plasma by labeled plasma protein and labeled serine. In order to determine the validity of this approach, the metabolic fate of labeled methionine was studied in six dogs. After injection with either [C3H3] methionine or [14CH3] methionine arterial blood was sampled. Plasma fractions containing protein were separated by fast gel filtration, counted with standard scintillation techniques, and their radioactivity was compared with total plasma radioactivity. Plasma was also separated by high-pressure liquid chromatography into methionine, serine, and nonmethionine or serine-containing fractions. These fractions were counted, and their radioactivity was compared with total plasma radioactivity. Labeled protein appeared in plasma about 20 minutes postinjection and then increased steadily. Labeled serine also appeared and reached a peak value of 9.4 +/- 2.1% of plasma activity at 40 minutes. Of greatest interest was the appearance in later plasma samples of increasing amounts of activity contained in nonserine low molecular weight metabolites of methionine. At 40 minutes, those metabolites made up 27 +/- 6.9% of total plasma activity

  19. Direct Solvent-Derived Polymer-Coated Nitrogen-Doped Carbon Nanodots with High Water Solubility for Targeted Fluorescence Imaging of Glioma.

    Science.gov (United States)

    Wang, Yi; Meng, Ying; Wang, Shanshan; Li, Chengyi; Shi, Wei; Chen, Jian; Wang, Jianxin; Huang, Rongqin

    2015-08-01

    Cancer imaging requires biocompatible and bright contrast-agents with selective and high accumulation in the tumor region but low uptake in normal tissues. Herein, 1-methyl-2-pyrrolidinone (NMP)-derived polymer-coated nitrogen-doped carbon nanodots (pN-CNDs) with a particle size in the range of 5-15 nm are prepared by a facile direct solvothermal reaction. The as-prepared pN-CNDs exhibit stable and adjustable fluorescence and excellent water solubility. Results of a cell viability test (CCK-8) and histology analysis both demonstrate that the pN-CNDs have no obvious cytotoxicity. Most importantly, the pN-CNDs can expediently enter glioma cells in vitro and also mediate glioma fluorescence imaging in vivo with good contrast via elevated passive targeting. PMID:25808813

  20. Synthesis of carbon-13 labelled carbonaceous deposits and their evaluation for potential use as surrogates to better understand the behaviour of the carbon-14-containing deposit present in irradiated PGA graphite

    Science.gov (United States)

    Payne, L.; Walker, S.; Bond, G.; Eccles, H.; Heard, P. J.; Scott, T. B.; Williams, S. J.

    2016-03-01

    The present work has used microwave plasma chemical vapour deposition to generate suitable isotopically labelled carbonaceous deposits on the surface of Pile Grade A graphite for use as surrogates for studying the behaviour of the deposits observed on irradiated graphite extracted from UK Magnox reactors. These deposits have been shown elsewhere to contain an enhanced concentration of 14C compared to the bulk graphite. A combination of Raman spectroscopy, ion beam milling with scanning electron microscopy and secondary ion mass spectrometry were used to determine topography and internal morphology in the formed deposits. Direct comparison was made against deposits found on irradiated graphite samples trepanned from a Magnox reactor core and showed a good similarity in appearance. This work suggests that the microwave plasma chemical vapour deposition technique is of value in producing simulant carbon deposits, being of sufficiently representative morphology for use in non-radioactive surrogate studies of post-disposal behaviour of 14C-containing deposits on some irradiated Magnox reactor graphite.

  1. Implication of extracellular zinc exclusion by recombinant human calprotectin (MRP8 and MRP14 from target cells in its apoptosis-inducing activity

    Directory of Open Access Journals (Sweden)

    Satoru Yui

    2002-01-01

    Full Text Available Background: Calprotectin is a calcium-binding and zinc-binding protein complex that is abundant in the cytosol of neutrophils. This factor is composed of 8 and 14 kDa subunits, which have also been termed migration inhibitory factor-related proteins MRP8 and MRP14. We previously reported that rat calprotectin purified from inflammatory neutrophils induces apoptosis of various tumor cells or normal fibroblasts in a zinc-reversible manner.

  2. Comparative phenomics and targeted use of genomics reveals variation in carbon and nitrogen assimilation among different Brettanomyces bruxellensis strains.

    Science.gov (United States)

    Crauwels, S; Van Assche, A; de Jonge, R; Borneman, A R; Verreth, C; Troels, P; De Samblanx, G; Marchal, K; Van de Peer, Y; Willems, K A; Verstrepen, K J; Curtin, C D; Lievens, B

    2015-11-01

    Recent studies have suggested a correlation between genotype groups of Brettanomyces bruxellensis and their source of isolation. To further explore this relationship, the objective of this study was to assess metabolic differences in carbon and nitrogen assimilation between different B. bruxellensis strains from three beverages, including beer, wine, and soft drink, using Biolog Phenotype Microarrays. While some similarities of physiology were noted, many traits were variable among strains. Interestingly, some phenotypes were found that could be linked to strain origin, especially for the assimilation of particular α- and β-glycosides as well as α- and β-substituted monosaccharides. Based upon gene presence or absence, an α-glucosidase and β-glucosidase were found explaining the observed phenotypes. Further, using a PCR screen on a large number of isolates, we have been able to specifically link a genomic deletion to the beer strains, suggesting that this region may have a fitness cost for B. bruxellensis in certain fermentation systems such as brewing. More specifically, none of the beer strains were found to contain a β-glucosidase, which may have direct impacts on the ability for these strains to compete with other microbes or on flavor production. PMID:26135985

  3. Targeted Fe-filled carbon nanotube as a multifunctional contrast agent for thermoacoustic and magnetic resonance imaging of tumor in living mice.

    Science.gov (United States)

    Ding, Wenzheng; Lou, Cunguang; Qiu, Jieshan; Zhao, Zongbin; Zhou, Quan; Liang, Minjie; Ji, Zhong; Yang, Sihua; Xing, Da

    2016-01-01

    Microwave-induced thermoacoustic imaging (TAI) can map the microwave absorption distribution of targets, which depends on the electrical and magnetic properties. Although carbon nanotubes (CNTs) with good electrical properties have been used as TAI contrast agents, the negligible magnetic absorption hinders its application for sensitive detection. In order to exploit CNTs with electrical and magnetic absorption properties as agent of TAI, the ferromagnetic material-filled multi-walled CNTs (MMWCNTs) are investigated. In this study, the folic acid conjugated plain multiwalled CNTs (MWCNTs) and MMWCNTs were injected through the tail-vein of mice separately, and TAI and magnetic resonance imaging (MRI) were performed. The results show the MMWCNTs can clearly image the size and edge of the tumor with the TAI contrast enhancement of 67% and T2 signal intensity decrease of four fifths compared to MWCNTs. This study demonstrated the hybrid particles have the potential to be a high-sensitive contrast agent for accurate tumor detection. From the Clinical Editor: Novel imaging modalities are emerging. Microwave-induced thermoacoustic imaging (TAI) relies on the absorption distribution of microwave of targets. In this article the authors investigate the use of ferromagnetic material-filled multi-walled CNTs as contrast agents for both TAI and MRI in an in-vivo model for tumors. The positive findings would imply that the application of dual-modality probe could provide more accurate imaging for the clinical setting.

  4. 全球长期减排目标与碳排放权分配原则%Long-Term Climate Change Mitigation Target and Carbon Permit Allocation

    Institute of Scientific and Technical Information of China (English)

    何建坤; 陈文颖; 滕飞; 刘滨

    2009-01-01

    Long-term climate change mitigation target would highly constrain global carbon emissions in future.Carbon permit allocation under the long-term mitigation target would impact development space for all countries,involving the fundamental interests.Some developed countries advocate the principle of per capita emission convergence while China and other developing countries propose the principle of convergence of accumulative emission per capita to consider historical responsibility.If the latter is used for carbon permit allocation,CO_2 emissions of developed countries since the industrial revolution have far exceeded their allocated permits.Developed countries'high per capita emissions at present and for quite a long period in future would continue to occupy emission spaces for developing countries.Therefore,developed countries must commit deeper emission reduction rate for the next commitment period at the Copenhagen conference in order to achieve the emission pathway under the long-term emission reduction target,and to save necessary development space for developing countries.At the same time,developed countries should provide adequate financial and technical suppoa as compensation for their overuse of the development space for developing countries,to improve developing countries'capacity to respond to climate change under the framework of sustainable development.On the one hand,we should insist on the principle of equity to obtain reasonable emission space for our country in the international climate change negotiation;while on the other hand,we should enhance development toward low-carbon economy to protect global environment and to achieve sustainable development.%全球长期减排目标将对世界未来的碳排放形成严重制约,减排义务的分担原则涉及各国的发展空间,事关根本利益.部分发达国家倡导人均排放趋同原则,回避发达国家的历史责任,中国等发展中国家提出人均累积排放趋同原则,强调公

  5. Targeting of Carbon Ion-Induced G2 Checkpoint Activation in Lung Cancer Cells Using Wee-1 Inhibitor MK-1775.

    Science.gov (United States)

    Ma, Hongyu; Takahashi, Akihisa; Sejimo, Yukihiko; Adachi, Akiko; Kubo, Nobuteru; Isono, Mayu; Yoshida, Yukari; Kanai, Tatsuaki; Ohno, Tatsuya; Nakano, Takashi

    2015-12-01

    The potent inhibitor of the cell cycle checkpoint regulatory factor Wee-1, MK-1775, has been reported to enhance non-small cell lung cancer (NSCLC) cell sensitivity to photon radiation by abrogating radiation-induced G2 arrest. However, little is known about the effects of this sensitizer after exposure to carbon (C)-ion radiation. The purpose of this study was therefore to investigate the effects of C ions in combination with MK-1775 on the killing of NSCLC cells. Human NSCLC H1299 cells were exposed to X rays or C ions (290 MeV/n, 50 keV/μm at the center of a 6 cm spread-out Bragg peak) in the presence of MK-1775. The cell cycle was analyzed using flow cytometry and Western blotting. Radiosensitivity was determined using clonogenic survival assays. The mechanisms underlying MK-1775 radiosensitization were studied by observing H2AX phosphorylation and mitotic catastrophe. G2 checkpoint arrest was enhanced 2.3-fold by C-ion exposure compared with X-ray exposure. Radiation-induced G2 checkpoint arrest was abrogated by MK-1775. Exposure to radiation resulted in a significant reduction in the mitotic ratio and increased phosphorylation of cyclin-dependent kinase 1 (Cdk1), the primary downstream mediator of Wee-1-induced G2 arrest. The Wee-1 inhibitor, MK-1775 restored the mitotic ratio and suppressed Cdk1 phosphorylation. In addition, MK-1775 increased H1299 cell sensitivity to C ions and X rays independent of TP53 status. MK-1775 also significantly increased H2AX phosphorylation and mitotic catastrophe in irradiated cells. These results suggest that the G2 checkpoint inhibitor MK-1775 can enhance the sensitivity of human NSCLC cells to C ions as well as X rays. PMID:26645158

  6. Synthesis and biological evaluation of copper-64 radiolabeled [DUPA-6-Ahx-(NODAGA)-5-Ava-BBN(7-14)NH2], a novel bivalent targeting vector having affinity for two distinct biomarkers (GRPr/PSMA) of prostate cancer

    International Nuclear Information System (INIS)

    Gastrin-releasing peptide receptors (GRPr) and prostate-specific membrane antigen (PSMA) are two identifying biomarkers expressed in very high numbers on prostate cancer cells and could serve as a useful tool for molecular targeting and diagnosis of disease via positron-emission tomography (PET). The aim of this study was to produce the multipurpose, bivalent [DUPA-6-Ahx-(64Cu-NODAGA)-5-Ava-BBN(7-14)NH2] radioligand for prostate cancer imaging, where DUPA = (2-[3-(1,3-dicarboxypropyl)-ureido]pentanedioic acid), a small-molecule, PSMA-targeting probe, 6Ahx = 6-aminohexanoic acid, 5-Ava = 5-aminovaleric acid, NODAGA = [2-(4,7-biscarboxymethyl)-1,4,7-(triazonan-1-yl)pentanedioic acid] (a derivative of NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid)), and BBN(7-14)NH2 = bombesin, a GRPr-specific peptide targeting probe. Methods: The PSMA/GRPr dual targeting ligand precursor [DUPA-6-Ahx-K-5-Ava-BBN(7-14)NH2], was synthesized by solid-phase and manual peptide synthesis, after which NODAGA was added via manual conjugation to the ε-amine of lysine (K). The new bivalent GRPr/PSMA targeting vector was purified by reversed-phase high performance liquid chromatography (RP-HPLC), characterized by electrospray-ionization mass spectrometry (ESI-MS), and metallated with 64CuCl2 and natCuCl2. The receptor binding affinity was evaluated in human, prostate, PC-3 (GRPr-positive) and LNCaP (PSMA-positive) cells and the tumor-targeting efficacy determined in severe combined immunodeficient (SCID) and athymic nude mice bearing PC-3 and LNCaP tumors. Whole-body maximum intensity microPET/CT images of PC-3/LNCaP tumor-bearing mice were obtained 18 h post-injection (p.i.). Results: Competitive binding assays in PC-3 and LNCaP cells indicated high receptor binding affinity for the [DUPA-6-Ahx-(natCu-NODAGA)-5-Ava-BBN(7-14)NH2] conjugate. MicroPET scintigraphy in PC-3/LNCaP tumor-bearing mice indicated that xenografted tumors were visible at 18 h p.i. with collateral, background

  7. Accelerated killing of cancer cells using a multifunctional single-walled carbon nanotube-based system for targeted drug delivery in combination with photothermal therapy

    Directory of Open Access Journals (Sweden)

    Jeyamohan P

    2013-07-01

    Full Text Available Prashanti Jeyamohan, Takashi Hasumura, Yutaka Nagaoka, Yasuhiko Yoshida, Toru Maekawa, D Sakthi Kumar Bio-Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, Japan Abstract: The photothermal effect of single-walled carbon nanotubes (SWCNTs in combination with the anticancer drug doxorubicin (DOX for targeting and accelerated destruction of breast cancer cells is demonstrated in this paper. A targeted drug-delivery system was developed for selective killing of breast cancer cells with polyethylene glycol biofunctionalized and DOX-loaded SWCNTs conjugated with folic acid. In our work, in vitro drug-release studies showed that the drug (DOX binds at physiological pH (pH 7.4 and is released only at a lower pH, ie, lysosomal pH (pH 4.0, which is the characteristic pH of the tumor environment. A sustained release of DOX from the SWCNTs was observed for a period of 3 days. SWCNTs have strong optical absorbance in the near-infrared (NIR region. In this special spectral window, biological systems are highly transparent. Our study reports that under laser irradiation at 800 nm, SWCNTs exhibited strong light–heat transfer characteristics. These optical properties of SWCNTs open the way for selective photothermal ablation in cancer therapy. It was also observed that internalization and uptake of folate-conjugated NTs into cancer cells was achieved by a receptor-mediated endocytosis mechanism. Results of the in vitro experiments show that laser was effective in destroying the cancer cells, while sparing the normal cells. When the above laser effect was combined with DOX-conjugated SWCNTs, we found enhanced and accelerated killing of breast cancer cells. Thus, this nanodrug-delivery system, consisting of laser, drug, and SWCNTs, looks to be a promising selective modality with high treatment efficacy and low side effects for cancer therapy. Keywords: cancer, nanotherapy, SWCNTs, targeted drug delivery

  8. 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.

  9. 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...

  10. Down-Regulation of KORRIGAN-Like Endo-β-1,4-Glucanase Genes Impacts Carbon Partitioning, Mycorrhizal Colonization and Biomass Production in Populus

    Science.gov (United States)

    Kalluri, Udaya C.; Payyavula, Raja S.; Labbé, Jessy L.; Engle, Nancy; Bali, Garima; Jawdy, Sara S.; Sykes, Robert W.; Davis, Mark; Ragauskas, Arthur; Tuskan, Gerald A.; Tschaplinski, Timothy J.

    2016-01-01

    A greater understanding of the genetic regulation of plant cell wall remodeling and the impact of modified cell walls on plant performance is important for the development of sustainable biofuel crops. Here, we studied the impact of down-regulating KORRIGAN-like cell wall biosynthesis genes, belonging to the endo-β-1,4-glucanase gene family, on Populus growth, metabolism and the ability to interact with symbiotic microbes. The reductions in cellulose content and lignin syringyl-to-guaiacyl unit ratio, and increase in cellulose crystallinity of cell walls of PdKOR RNAi plants corroborated the functional role of PdKOR in cell wall biosynthesis. Altered metabolism and reduced growth characteristics of RNAi plants revealed new implications on carbon allocation and partitioning. The distinctive metabolome phenotype comprised of a higher phenolic and salicylic acid content, and reduced lignin, shikimic acid and maleic acid content relative to control. Plant sustainability implications of modified cell walls on beneficial plant-microbe interactions were explored via co-culture with an ectomycorrhizal fungus, Laccaria bicolor. A significant increase in the mycorrhization rate was observed in transgenic plants, leading to measurable beneficial growth effects. These findings present new evidence for functional interconnectedness of cellulose biosynthesis pathway, metabolism and mycorrhizal association in plants, and further emphasize the consideration of the sustainability implications of plant trait improvement efforts. PMID:27757116

  11. Interfacial Microstructure and Enhanced Mechanical Properties of Carbon Fiber Composites Caused by Growing Generation 1-4 Dendritic Poly(amidoamine) on a Fiber Surface.

    Science.gov (United States)

    Gao, Bo; Zhang, Ruliang; Gao, Fucheng; He, Maoshuai; Wang, Chengguo; Liu, Lei; Zhao, Lifen; Cui, Hongzhi

    2016-08-23

    In an attempt to improve the mechanical properties of carbon fiber composites, propagation of poly(amidoamine) (PAMAM) dendrimers by in situ polymerization on a carbon fiber surface was performed. During polymerization processes, PAMAM was grafted on carbon fiber by repeated Michael addition and amidation reactions. The changes in surface microstructure and the chemical composition of carbon fibers before and after modification were investigated by atomic force microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. All the results indicated that PAMAM was successfully grown on the carbon fiber surface. Such propagation could significantly increase the surface roughness and introduce sufficient polar groups onto the carbon fiber surface, enhancing the surface wettability of carbon fiber. The fractured surface of carbon fiber-reinforced composites showed a great enhancement of interfacial adhesion. Compared with those of desized fiber composites, the interlaminar shear strength and interfacial shear strength of PAMAM/fiber-reinforced composites showed increases of 55.49 and 110.94%, respectively.

  12. Carbon nanoparticles induce ceramide- and lipid raft-dependent signalling in lung epithelial cells: a target for a preventive strategy against environmentally-induced lung inflammation

    Directory of Open Access Journals (Sweden)

    Peuschel Henrike

    2012-12-01

    Full Text Available Abstract Background Particulate air pollution in lung epithelial cells induces pathogenic endpoints like proliferation, apoptosis, and pro-inflammatory reactions. The activation of the epidermal growth factor receptor (EGFR is a key event responsible for signalling events involving mitogen activated protein kinases specific for these endpoints. The molecular events leading to receptor activation however are not well understood. These events are relevant for the toxicological evaluation of inhalable particles as well as for potential preventive strategies in situations when particulate air pollution cannot be avoided. The current study therefore had the objective to elucidate membrane-coupled events leading to EGFR activation and the subsequent signalling cascade in lung epithelial cells. Furthermore, we aimed to identify the molecular target of ectoine, a biophysical active substance which we described to prevent carbon nanoparticle-induced lung inflammation. Methods Membrane signalling events were investigated in isolated lipid rafts from lung epithelial cells with regard to lipid and protein content of the signalling platforms. Using positive and negative intervention approaches, lipid raft changes, subsequent signalling events, and lung inflammation were investigated in vitro in lung epithelial cells (RLE-6TN and in vivo in exposed animals. Results Carbon nanoparticle treatment specifically led to an accumulation of ceramides in lipid rafts. Detailed analyses demonstrated a causal link of ceramides and subsequent EGFR activation coupled with a loss of the receptor in the lipid raft fractions. In vitro and in vivo investigations demonstrate the relevance of these events for carbon nanoparticle-induced lung inflammation. Moreover, the compatible solute ectoine was able to prevent ceramide-mediated EGFR phosphorylation and subsequent signalling as well as lung inflammation in vivo. Conclusion The data identify a so far unknown event in pro

  13. Structural Basis for Rational Design of Inhibitors Targeting Trypanosoma cruzi Sterol 14α-Demethylase: Two Regions of the Enzyme Molecule Potentiate Its Inhibition

    OpenAIRE

    Friggeri, Laura; Hargrove, Tatiana Y.; Rachakonda, Girish; Williams, Amanda D; Wawrzak, Zdzislaw; Di Santo, Roberto; De Vita, Daniela; Waterman, Michael R.; Tortorella, Silvano; Villalta, Fernando; Lepesheva, Galina I.

    2014-01-01

    Chagas disease, which was once thought to be confined to endemic regions of Latin America, has now gone global, becoming a new worldwide challenge with no cure available. The disease is caused by the protozoan parasite Trypanosoma cruzi, which depends on the production of endogenous sterols, and therefore can be blocked by sterol 14α-demethylase (CYP51) inhibitors. Here we explore the spectral binding parameters, inhibitory effects on T. cruzi CYP51 activity, and antiparasitic potencies of a ...

  14. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Thomas C. Chidsey; Kevin McClure; Craig D. Morgan

    2003-10-05

    thickest part of the mound facies of the upper Ismay zone, where microporosity is well developed. In Bug field, the most productive wells are located structurally downdip from the updip porosity pinch out in the dolomitized lower Desert Creek zone, where micro-box-work porosity is well developed. Microporosity and micro-box-work porosity have the greatest hydrocarbon storage and flow capacity, and potential horizontal drilling target in these fields. Diagenesis is the main control on the quality of Ismay and Desert Creek reservoirs. Most of the carbonates present within the lower Desert Creek and Ismay have retained a marine-influenced carbon isotope geochemistry throughout marine cementation as well as through post-burial recycling of marine carbonate components during dolomitization, stylolitization, dissolution, and late cementation. Meteoric waters do not appear to have had any effect on the composition of the dolomites in these zones. Light oxygen values obtained from reservoir samples for wells located along the margins or flanks of Bug field may be indicative of exposure to higher temperatures, to fluids depleted in {sup 18}O relative to sea water, or to hypersaline waters during burial diagenesis. The samples from Bug field with the lightest oxygen isotope compositions are from wells that have produced significantly greater amounts of hydrocarbons. There is no significant difference between the oxygen isotope compositions from lower Desert Creek dolomite samples in Bug field and the upper Ismay limestones and dolomites from Cherokee field. Carbon isotopic compositions for samples from Patterson Canyon field can be divided into two populations: isotopically heavier mound cement and isotopically lighter oolite and banded cement. Technology transfer activities consisted of exhibiting a booth display of project materials at the annual national convention of the American Association of Petroleum Geologists, a technical presentation, a core workshop, and publications

  15. Integrated molecular targeting of IGF1R and HER2 surface receptors and destruction of breast cancer cells using single wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Shao Ning [Delaware MEMS and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 (United States); Lu Shaoxin [Delaware MEMS and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 (United States); Wickstrom, Eric [Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Panchapakesan, Balaji [Delaware MEMS and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Delaware, Newark, DE 19716 (United States)

    2007-08-08

    Molecular targeting and photodynamic therapy have shown great potential for selective cancer therapy. We hypothesized that monoclonal antibodies that are specific to the IGF1 receptor and HER2 cell surface antigens could be bound to single wall carbon nanotubes (SWCNT) in order to concentrate SWCNT on breast cancer cells for specific near-infrared phototherapy. SWCNT functionalized with HER2 and IGF1R specific antibodies showed selective attachment to breast cancer cells compared to SWCNT functionalized with non-specific antibodies. After the complexes were attached to specific cancer cells, SWCNT were excited by {approx}808 nm infrared photons at {approx}800 mW cm{sup -2} for 3 min. Viability after phototherapy was determined by Trypan blue exclusion. Cells incubated with SWCNT/non-specific antibody hybrids were still alive after photo-thermal treatment due to the lack of SWNT binding to the cell membrane. All cancerous cells treated with IGF1R and HER2 specific antibody/SWCNT hybrids and receiving infrared photons showed cell death after the laser excitation. Quantitative analysis demonstrated that all the cells treated with SWCNT/IGF1R and HER2 specific antibody complex were completely destroyed, while more than 80% of the cells with SWCNT/non-specific antibody hybrids remained alive. Following multi-component targeting of IGF1R and HER2 surface receptors, integrated photo-thermal therapy in breast cancer cells led to the complete destruction of cancer cells. Functionalizing SWCNT with antibodies in combination with their intrinsic optical properties can therefore lead to a new class of molecular delivery and cancer therapeutic systems.

  16. The Subaru FMOS galaxy redshift survey (FastSound). I. Overview of the survey targeting Hα emitters at z ˜ 1.4

    Science.gov (United States)

    Tonegawa, Motonari; Totani, Tomonori; Okada, Hiroyuki; Akiyama, Masayuki; Dalton, Gavin; Glazebrook, Karl; Iwamuro, Fumihide; Maihara, Toshinori; Ohta, Kouji; Shimizu, Ikkoh; Takato, Naruhisa; Tamura, Naoyuki; Yabe, Kiyoto; Bunker, Andrew J.; Coupon, Jean; Ferreira, Pedro G.; Frenk, Carlos S.; Goto, Tomotsugu; Hikage, Chiaki; Ishikawa, Takashi; Matsubara, Takahiko; More, Surhud; Okumura, Teppei; Percival, Will J.; Spitler, Lee R.; Szapudi, Istvan

    2015-10-01

    FastSound is a galaxy redshift survey that uses the near-infrared Fiber Multi-Object Spectrograph (FMOS) mounted on the Subaru Telescope, targeting Hα emitters at z ˜ 1.18-1.54 down to the sensitivity limit of Hα flux ˜ 2 × 10-16 erg cm-2 s-1. The primary goal of the survey is to detect redshift space distortion (RSD), to test the general theory of relativity by measuring the growth rate of large-scale structure and to constrain modified gravity models for the origin of the accelerated expansion of the universe. The target galaxies were selected based on photometric redshifts and Hα flux estimates calculated by fitting spectral energy distribution (SED) models to the five optical magnitudes of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) Wide catalog. The survey started in 2012 March, and all the observations were completed in 2014 July. In total, we achieved 121 pointings of FMOS (each pointing has a 30' diameter circular footprint) covering 20.6 deg2 by tiling the four fields of the CFHTLS Wide in a hexagonal pattern. Emission lines were detected from ˜ 4000 star-forming galaxies by an automatic line detection algorithm applied to 2D spectral images. This is the first in a series of papers based on FastSound data, and we describe the details of the survey design, target selection, observations, data reduction, and emission line detections.

  17. MiR-133a regarded as a potential biomarker for benzene toxicity through targeting Caspase-9 to inhibit apoptosis induced by benzene metabolite (1,4-Benzoquinone).

    Science.gov (United States)

    Chen, Yujiao; Sun, Pengling; Bai, Wenlin; Gao, Ai

    2016-11-15

    Benzene is an environmental and industrial chemical which is widely utilized in various applications. Our previous study showed that miR-133a expression was down-regulated in chronic benzene poisoning workers, but the mechanism of miR-133a in benzene-induced hematotoxicity remains unclear. In this population-based study, benzene-exposed group recruited workers whose concentration of air benzene was 3.50±1.60mg/m(3), and control workers who were exposed to 0.06±0.01mg/m(3) air benzene. By comparison, Caspase-9 and Caspase-3 was up-regulated while miR-133a expression decreased in benzene-exposed workers. Pearson correlation analysis showed that miR-133a was reversely correlated with pro-apoptotic gene Caspase-9 in population-based study. Moreover, multiple linear regressions indicated that miR-133a was positively associated with blood cells count. To explore the underlying mechanism of miR-133a in benzene-induced hematotoxicity, AO/EB staining and TEM ultrastructural analysis were conducted to verify the activation of apoptosis in Human Leukemic U937 Cells induced by benzene metabolites (1,4-Benzoquinone, 1,4-BQ), while the mechanism of miR-133a in 1,4-BQ-induced apoptosis was performed using lentivirus vectors transfection. The results demonstrated that 1,4-BQ evidently induced mitochondria-mediated apoptosis and increased pro-apoptotic genes (Caspase-9 and Caspase-3) expression in a dose-dependent manner. The mechanistic study showed 1,4-BQ decreased miR-133a expression and miR-133a over-expression attenuated 1, 4-BQ-caused upregulation of Caspase-9, Caspase-3 and apoptosis. In conclusion, our research suggested that benzene induced hematotoxicity by decreasing miR-133a and caspase-dependent apoptosis which might contribute to the underlying mechanism of miR-133a in benzene-induced hematotoxicity.

  18. Large-angle production of charged pions by 3 GeV/c - 12 GeV/c protons on carbon, copper and tin targets

    CERN Document Server

    Catanesi, M G; Edgecock, R; Ellis, M; Robbins, S; Soler, F J P; Gössling, C; Bunyatov, S; Krasnoperov, A; Popov, B; Serdiouk, V; Tereschenko, V; Di Capua, E; Vidal-Sitjes, G; Artamonov, A; Arce, P; Giani, S; Gilardoni, S; Gorbunov, P; Grant, A; Grossheim, A; Gruber, P; Ivanchenko, V; Kayis-Topaksu, A; Panman, J; Papadopoulos, I; Pasternak, J; Chernyaev, E; Tsukerman, I; Veenhof, R; Wiebusch, C; Zucchelli, P; Blondel, A; Borghi, S; Campanelli, M; Morone, M C; Prior, G; Schroeter, R; Engel, R; Meurer, C; Kato, I; Gastaldi, Ugo; Mills, G B; Graulich, J S; Grégoire, G; Bonesini, M; Ferri, F; Paganoni, M; Paleari, F; Kirsanov, M; Bagulya, A; Grichine, V; Polukhina, N; Palladino, V; Coney, L; Schmitz, D; Barr, G; De Santo, A; Pattison, C; Zuber, K; Bobisut, F; Gibin, D; Guglielmi, A; Mezzetto, M; Dumarchez, J; Vannucci, F; Dore, U; Orestano, D; Pastore, F; Tonazzo, A; Tortora, L; Booth, C; Buttar, C; Hodgson, P; Howlett, L; Bogomilov, M; Chizhov, M; Kolev, D; Tsenov, R; Piperov, S; Temnikov, P; Apollonio, M; Chimenti, P; Giannini, G; Santin, G; Burguet-Castell, J; Cervera-Villanueva, A; Gómez-Cadenas, J J; Martín-Albo, J; Novella, P; Sorel, M; Tornero, A

    2008-01-01

    A measurement of the double-differential $\\pi^{\\pm}$ production cross-section in proton--carbon, proton--copper and proton--tin collisions in the range of pion momentum $100 \\MeVc \\leq p < 800 \\MeVc$ and angle $0.35 \\rad \\le \\theta <2.15 \\rad$ is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \\GeVc to 12 \\GeVc hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections at four incident proton beam momenta (3 \\GeVc, 5 \\GeVc, 8 \\GeVc and 12 \\GeVc).

  19. Large-angle production of charged pions by 3 GeV/c-12 GeV/c protons on carbon, copper and tin targets

    Science.gov (United States)

    Catanesi, M. G.; Radicioni, E.; Edgecock, R.; Ellis, M.; Robbins, S.; Soler, F. J. P.; Gößling, C.; Bunyatov, S.; Krasnoperov, A.; Popov, B.; Serdiouk, V.; Tereschenko, V.; di Capua, E.; Vidal-Sitjes, G.; Arce, P.; Artamonov, A.; Giani, S.; Gilardoni, S.; Gorbunov, P.; Grant, A.; Grossheim, A.; Gruber, P.; Ivanchenko, V.; Kayis-Topaksu, A.; Panman, J.; Papadopoulos, I.; Pasternak, J.; Tcherniaev, E.; Tsukerman, I.; Veenhof, R.; Wiebusch, C.; Zucchelli, P.; Blondel, A.; Borghi, S.; Campanelli, M.; Morone, M. C.; Prior, G.; Schroeter, R.; Engel, R.; Meurer, C.; Kato, I.; Gastaldi, U.; Mills, G. B.; Graulich, J. S.; Grégoire, G.; Kirsanov, M.; Bonesini, M.; Ferri, F.; Paganoni, M.; Paleari, F.; Bagulya, A.; Grichine, V.; Polukhina, N.; Palladino, V.; Coney, L.; Schmitz, D.; Barr, G.; de Santo, A.; Pattison, C.; Zuber, K.; Bobisut, F.; Gibin, D.; Guglielmi, A.; Mezzetto, M.; Dumarchez, J.; Vannucci, F.; Dore, U.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Booth, C.; Buttar, C.; Hodgson, P.; Howlett, L.; Bogomilov, M.; Chizhov, M.; Kolev, D.; Tsenov, R.; Piperov, S.; Temnikov, P.; Apollonio, M.; Chimenti, P.; Giannini, G.; Santin, G.; Burguet-Castell, J.; Cervera-Villanueva, A.; Gómez-Cadenas, J. J.; Martín-Albo, J.; Novella, P.; Sorel, M.; Tornero, A.

    2008-01-01

    A measurement of the double-differential π± production cross-section in proton-carbon, proton-copper and proton-tin collisions in the range of pion momentum 100 MeV/ c≤p<800 MeV/ c and angle 0.35 rad≤θ<2.15 rad is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/ c to 12 GeV/ c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections d2σ/dpdθ at four incident proton beam momenta (3 GeV/ c, 5 GeV/ c, 8 GeV/ c and 12 GeV/ c).

  20. Methylation of MGMT and ADAMTS14 in normal colon mucosa: biomarkers of a field defect for cancerization preferentially targeting elder African-Americans.

    Science.gov (United States)

    Alonso, Sergio; Dai, Yuichi; Yamashita, Kentaro; Horiuchi, Shina; Dai, Tomoko; Matsunaga, Akihiro; Sánchez-Muñoz, Rosa; Bilbao-Sieyro, Cristina; Díaz-Chico, Juan Carlos; Chernov, Andrei V; Strongin, Alex Y; Perucho, Manuel

    2015-02-20

    Somatic hypermethylation of the O6-methylguanine-DNA methyltransferase gene (MGMT) was previously associated with G > A transition mutations in KRAS and TP53 in colorectal cancer (CRC). We tested the association of MGMT methylation with G > A mutations in KRAS and TP53 in 261 CRCs. Sixteen cases, with and without MGMT hypermethylation, were further analyzed by exome sequencing. No significant association of MGMT methylation with G > A mutations in KRAS, TP53 or in the whole exome was found (p > 0.5 in all comparisons). The result was validated by in silico comparison with 302 CRCs from The Cancer Genome Atlas (TCGA) consortium dataset. Transcriptional silencing associated with hypermethylation and stratified into monoallelic and biallelic. We also found a significant clustering (p = 0.001) of aberrant hypermethylation of MGMT and the matrix metalloproteinase gene ADAMTS14 in normal colonic mucosa of CRC patients. This suggested the existence of an epigenetic field defect for cancerization disrupting the methylation patterns of several loci, including MGMT or ADAMTS14, that may lead to predictive biomarkers for CRC. Methylation of these loci in normal mucosa was more frequent in elder (p = 0.001) patients, and particularly in African Americans (p = 1 × 10-5), thus providing a possible mechanistic link between somatic epigenetic alterations and CRC racial disparities in North America. PMID:25638164

  1. The preparation of nucleotides uniformly labelled with carbon-14 by biosynthetic methods. Isolation of adenylic, uridylic, cytidylic,and guanylic acids, from the alkaline hydrolysate of escherichia coli RNA

    International Nuclear Information System (INIS)

    A method is described for the preparation and analysis of adenylic, uri dilic, cytidi- 11c and guanylic acids, labelled with 14C. Escherichia coli cells have been labelled by growing them in a medi dia containing glucose-14C as their only source of carbon. RNA is isolated from the cells, and after hydrolysis of the molecule the resulting nucleotides are separated by gel filtration and exchange chromatography. Chemical and radiochemical purity of the Isolated nucleotides is determined, and also its specific radioactivity. (Author) 30 refs

  2. Efficacy and Toxicity of Mammalian Target Rapamycin Inhibitors in Patients with Metastatic Renal Cell Carcinoma with Renal Insufficiency: The Korean Cancer Study Group GU 14-08

    Science.gov (United States)

    Kim, Ki Hyang; Kim, Joo Hoon; Lee, Ji Young; Kim, Hyo Song; Heo, Su Jin; Kim, Ji Hyung; Kim, Ho Young; Rha, Sun Young

    2016-01-01

    Purpose We evaluated the efficacy and toxicity of mammalian target rapamycin inhibitors in Korean patients with metastatic renal cell carcinoma (mRCC) with chronic renal insufficiency not requiring dialysis. Materials and Methods Korean patients with mRCC and chronic renal insufficiency not requiring dialysis treated with everolimus or temsirolimus between January 2008 and December 2014 were included. Patient characteristics, clinical outcomes, and toxicities were evaluated. Overall survival (OS) and progression-free survival (PFS) durations were evaluated according to the degree of renal impairment. Results Eighteen patients were considered eligible for the study (median age, 59 years). The median glomerular filtration rate was 51.5 mL/min/1.73 m2. The best response was partial response in six patients and stable disease in 11 patients. The median PFS and OS durations were 8 months (95% confidence interval [CI], 0 to 20.4) and 32 months (95% CI, 27.5 to 36.5), respectively. The most common non-hematologic and grade 3/4 adverse events included stomatitis, fatigue, flu-like symptoms, and anorexia as well as elevated creatinine level. Conclusion Mammalian target rapamycin inhibitors were efficacious and did not increase toxicity in Korean patients with mRCC and chronic renal insufficiency not requiring dialysis. PMID:26875195

  3. Electron loss from 1.4 MEV/u U{sup 4,6,10+} ions colliding with Ne, N{sub 2} and Ar targets

    Energy Technology Data Exchange (ETDEWEB)

    DuBois, R.D. [Missouri Univ., Rolla, MO (United States); Santos, A.C.F. [Centro Federal de Educacao Tecnologica de Quimica, Rio de Janeiro (Brazil); Stoehlker, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (DE). Abt. Atomphysik] [and others

    2004-07-01

    Absolute, total, single, and multiple electron loss cross sections are measured for 1.4 MeV/u U{sup 4,6,10+} ions colliding with neon and argon atoms and nitrogen molecules. It is found that the cross sections all have the same dependence on the number of electrons lost and that multiplying the cross sections by the initial number of electrons in the 6s, 6p, and 5f shells yields good agreement between the different projectiles. By combining the present data with previous measurements made at the same velocity, it is shown that the scaled cross sections slowly decrease in magnitude for incoming charge states between 1 and 10 whereas the cross sections for higher charge state ions fall off much more rapidly. (orig.)

  4. Lake highstands on the Altiplano (Tropical Andes) contemporaneous with Heinrich 1 and the Younger Dryas : new insights from (14)C, U-Th dating and delta(18)O of carbonates

    OpenAIRE

    Blard, P.H.; Sylvestre, Florence; A. K. Tripati; Claude, C.; Causse, C.; Coudrain, Anne; Condom, Thomas; Seidel, J.L.; Vimeux, Françoise; Moreau, C; Dumoulin, J.P.; J. Lavé

    2011-01-01

    This study provides new geochronological and stable isotope constraints on Late Pleistocene fluctuations in lake level that occurred in the closed-watershed of the Central Altiplano between similar to 25 and similar to 12 ka. U-series isochrons and (14)C ages from carbonates are used to confirm and refine the previous chronology published (Placzek et al., 2006b). Our new data support three successive lake highstands during the Late Pleistocene: (i) the lake Sajsi cycle, from similar to 25 to ...

  5. The synthesis of [14C]-3S,4R-4-(4-fluorophenyl)-3-(3,4-methylenedioxyphenoxymethyl) piperidine hydrochloride (BRL 29060A), and mechanistic studies using carbon-13 labelling

    International Nuclear Information System (INIS)

    Paroxetine, BRL 29060A has been labelled with both carbon-14 and carbon-13. Hydroxymethylation of 4-(4-fluorophenyl)-1-methyl-1,2,5,6-tetrahydropyridine, using [14C]formaldehyde, produced an enantiomeric mixture of products which was taken without separation through a multistage sequence. Resolution of the mixture of stereoisomers at the penultimate step gave [14C]BRL 29060A with the required configuration. The overall radiochemical yield was 8%. At some stage in this process, as shown by C-13 labelling studies, scrambling of the label took place to give BRL 29060A with the majority of the label in the C-2 position of the piperidine ring and the remainder at the expected 7-methylene position. Further investigations of this route using carbon-13 as the label are described. When sesamol, (3,4-methylenedioxyphenol) was reacted with the O-benzene sulphonate of -cis-4-(4-fluorophenyl)-3-(hydroxy[13C]methyl-l-methylpiperidine, an inversion of configuration resulted via the previously described 1-aza[3.1.1]bicycloheptane ring system. It is also shown that the corresponding -trans-substituted piperidine, under similar conditions, does not undergo this inversion. (Author)

  6. The synthesis of [[sup 14]C]-3S,4R-4-(4-fluorophenyl)-3-(3,4-methylenedioxyphenoxymethyl) piperidine hydrochloride (BRL 29060A), and mechanistic studies using carbon-13 labelling

    Energy Technology Data Exchange (ETDEWEB)

    Willcocks, K.; Rustidge, D.C.; Tidy, D.J.D. (SmithKline Beecham Pharmaceuticals Research Div., Harlow (United Kingdom)); Barnes, R.D. (SmithKline Beecham Pharmaceuticals Div., Betchworth (United Kingdom). Chemotherapeutic Research Centre)

    1993-01-01

    Paroxetine, BRL 29060A has been labelled with both carbon-14 and carbon-13. Hydroxymethylation of 4-(4-fluorophenyl)-1-methyl-1,2,5,6-tetrahydropyridine, using [[sup 14]C]formaldehyde, produced an enantiomeric mixture of products which was taken without separation through a multistage sequence. Resolution of the mixture of stereoisomers at the penultimate step gave [[sup 14]C]BRL 29060A with the required configuration. The overall radiochemical yield was 8%. At some stage in this process, as shown by C-13 labelling studies, scrambling of the label took place to give BRL 29060A with the majority of the label in the C-2 position of the piperidine ring and the remainder at the expected 7-methylene position. Further investigations of this route using carbon-13 as the label are described. When sesamol, (3,4-methylenedioxyphenol) was reacted with the O-benzene sulphonate of -cis-4-(4-fluorophenyl)-3-(hydroxy[[sup 13]C]methyl-l-methylpiperidine), an inversion of configuration resulted via the previously described 1-aza[3.1.1]bicycloheptane ring system. It is also shown that the corresponding -trans-substituted piperidine, under similar conditions, does not undergo this inversion. (Author).

  7. Seasonal and snowmelt-driven changes in the water-extractable organic carbon dynamics in a cool-temperate Japanese forest soil, estimated using the bomb-14C tracer

    International Nuclear Information System (INIS)

    Water-extractable organic carbon (WEOC) in soil consists of a mobile and bioavailable portion of the dissolved organic carbon (DOC) pool. WEOC plays an important role in dynamics of soil organic carbon (SOC) and transport of radionuclides in forest soils. Although considerable research has been conducted on the importance of recent litter versus older soil organic matter as WEOC sources in forest soil, a more thorough evaluation of the temporal pattern of WEOC is necessary. We investigated the seasonal variation in WEOC in a Japanese cool-temperate beech forest soil by using the carbon isotopic composition (14C and 13C) of WEOC as a tracer for the carbon sources. Our observations demonstrated that fresh leaf litter DOC significantly contributed to WEOC in May (35–52%) when the spring snowmelt occurred because of the high water flux and low temperature. In the rainy season, increases in the concentration of WEOC and the proportion of hydrophobic compounds were caused by high microbial activity under wetter conditions. From summer to autumn, the WEOC in the mineral soil horizons was also dominated by microbial release from SOC (>90%). These results indicate that the origin and dynamics of WEOC are strongly controlled by seasonal events such as the spring snowmelt and the rainy season's intense rainfall. -- Highlights: • 14C and 13C were used for a tracer for the carbon sources of WEOC in a forest soil. • Fresh leaf litter DOC significantly contributed to WEOC in the spring snowmelt. • Microbial activity caused the increase of WEOC concentration in the rainy season

  8. The preparation of nucleotides uniformly labelled with carbon-14 by biosynthetic methods. Isolation of adenylic, uridylic, cytidylic,and guanylic acids, from the alkaline hydrolysate of escherichia coli RNA; Preparacion de nucleiotidos uniformemente marcados con 14{sup C}, por via biosintetica. Aislamiento de los acidos adenilico, uridilico, citidilico y guanilico, procedentes de la hidrolisis alcalina de RNA de escherichia Coli.

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Pineda, M. D.; Pacheco Lopez, J.

    1978-07-01

    A method is described for the preparation and analysis of adenylic, uri dilic, cytidi- 11c and guanylic acids, labelled with 14{sup C}. Escherichia coli cells have been labelled by growing them in a medi dia containing glucose-14{sup C} as their only source of carbon. RNA is isolated from the cells, and after hydrolysis of the molecule the resulting nucleotides are separated by gel filtration and exchange chromatography. Chemical and radiochemical purity of the Isolated nucleotides is determined, and also its specific radioactivity. (Author) 30 refs.

  9. The potential of carbon-11 and fluorine-18 chemistry: illustration through the development of positron emission tomography radioligands targeting the translocator protein 18 kDa

    International Nuclear Information System (INIS)

    The TSPO (translocator protein), also known as the peripheral benzodiazepine receptor, is up-regulated in the brain of subjects suffering from neuro-degenerative disorders such as Alzheimer's, Parkinson's and Huntington's disease. Moreover, this overexpression has been proved to be linked to micro-glia activation making thus the TSPO a marker of choice of neuro-inflammatory processes and therefore a potential target for the development of radioligands for positron emission tomography imaging. The discovery of selective TSPO ligands and their labelling with the short-lived positron-emitter isotopes carbon-11 and fluorine-18 emerged in the mid-1980's with the preparation of the 3-iso-quinolinecarboxamide [11C]PK11195. To date, an impressive number of promising compounds - [11C]PK11195-challengers - have been developed; some radioligands - for example, [11C]PBR28, [11C]DPA-713, [18F]FEDAA1106 and [18F]DPA-714 - are currently used in clinical trials. As illustrated in this review, the methodologies applied for the preparation of these compounds remain mainly [11C]methylations using [11C]MeI or [11C]MeOTf and SN2- type nucleophilic aliphatic [18F]fluorinations - two processes illustrating the state-of-the-art arsenal of reactions that involves these two short-lived radioisotopes - but alternative processes, such as [11C]carbonylations using [11C]CO and [11C]COCl2 as well as SNAr-type nucleophilic [18F]fluorinations, have also been reported and as such, reviewed herein. (authors)

  10. Docetaxel-loaded single-wall carbon nanohorns using anti-VEGF antibody as a targeting agent: characterization, in vitro and in vivo antitumor activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Qian; Li, Nannan; Shu, Chang; Li, Ruixin; Ma, Xiaona; Li, Xuequan; Wang, Ran; Zhong, Wenying, E-mail: wyzhong@cpu.edu.cn [China Pharmaceutical University, Department of Analytical Chemistry (China)

    2015-05-15

    A novel antitumor drug delivery system, docetaxel (DTX)-loaded oxidized single-wall carbon nanohorns (oxSWNHs) with anti-VEGF monoclonal antibody (mAb) as a target agent was constructed. DTX was absorbed onto the oxSWNHs via the physical adsorption or π–π interaction. DSPE–PEG–COOH was non-covalently wrapped to the hydrophobic surface of oxSWNHs to improve its water solubility and biocompatibility. The mAb was bonded to the PEG through amide bond. The DTX@oxSWNHs-PEG-mAb (DDS) exhibited suitable particle size (191.2 ± 2.1 nm), good particle size distribution (PDI: 0.196), and negative zeta potential (−24.3 ± 0.85 mV). These features enhanced permeability and retention (EPR) effect and reduced the drug molecule uptake by the reticuloendothelial system. The in vitro drug release followed non-Fickian diffusion (n = 0.6857, R = 0.9924) with the cumulative release of DTX 59 ± 1.35 % at 72 h. Compared with free DTX, the DDS enhanced the cytotoxicity in MCF-7 cell lines in vitro efficiently (IC{sub 50}: 2.96 ± 0.6 μg/ml), and provided higher antitumor efficacy (TGI: 69.88 %) in vivo. The histological analysis indicated that the DDS had no significant side effect. Therefore, the new DDS is promising to attain higher pharmaceutical efficacy and lower side effects than free DTX for cancer therapy. The research demonstrated that DTX@oxSWNHs-PEG-mAb might have promising biomedical applications for future cancer therapy.

  11. Docetaxel-loaded single-wall carbon nanohorns using anti-VEGF antibody as a targeting agent: characterization, in vitro and in vivo antitumor activity

    International Nuclear Information System (INIS)

    A novel antitumor drug delivery system, docetaxel (DTX)-loaded oxidized single-wall carbon nanohorns (oxSWNHs) with anti-VEGF monoclonal antibody (mAb) as a target agent was constructed. DTX was absorbed onto the oxSWNHs via the physical adsorption or π–π interaction. DSPE–PEG–COOH was non-covalently wrapped to the hydrophobic surface of oxSWNHs to improve its water solubility and biocompatibility. The mAb was bonded to the PEG through amide bond. The DTX@oxSWNHs-PEG-mAb (DDS) exhibited suitable particle size (191.2 ± 2.1 nm), good particle size distribution (PDI: 0.196), and negative zeta potential (−24.3 ± 0.85 mV). These features enhanced permeability and retention (EPR) effect and reduced the drug molecule uptake by the reticuloendothelial system. The in vitro drug release followed non-Fickian diffusion (n = 0.6857, R = 0.9924) with the cumulative release of DTX 59 ± 1.35 % at 72 h. Compared with free DTX, the DDS enhanced the cytotoxicity in MCF-7 cell lines in vitro efficiently (IC50: 2.96 ± 0.6 μg/ml), and provided higher antitumor efficacy (TGI: 69.88 %) in vivo. The histological analysis indicated that the DDS had no significant side effect. Therefore, the new DDS is promising to attain higher pharmaceutical efficacy and lower side effects than free DTX for cancer therapy. The research demonstrated that DTX@oxSWNHs-PEG-mAb might have promising biomedical applications for future cancer therapy.

  12. Structure-Function Analysis of PPP1R3D, a Protein Phosphatase 1 Targeting Subunit, Reveals a Binding Motif for 14-3-3 Proteins which Regulates its Glycogenic Properties.

    Directory of Open Access Journals (Sweden)

    Carla Rubio-Villena

    Full Text Available Protein phosphatase 1 (PP1 is one of the major protein phosphatases in eukaryotic cells. It plays a key role in regulating glycogen synthesis, by dephosphorylating crucial enzymes involved in glycogen homeostasis such as glycogen synthase (GS and glycogen phosphorylase (GP. To play this role, PP1 binds to specific glycogen targeting subunits that, on one hand recognize the substrates to be dephosphorylated and on the other hand recruit PP1 to glycogen particles. In this work we have analyzed the functionality of the different protein binding domains of one of these glycogen targeting subunits, namely PPP1R3D (R6 and studied how binding properties of different domains affect its glycogenic properties. We have found that the PP1 binding domain of R6 comprises a conserved RVXF motif (R102VRF located at the N-terminus of the protein. We have also identified a region located at the C-terminus of R6 (W267DNND that is involved in binding to the PP1 glycogenic substrates. Our results indicate that although binding to PP1 and glycogenic substrates are independent processes, impairment of any of them results in lack of glycogenic activity of R6. In addition, we have characterized a novel site of regulation in R6 that is involved in binding to 14-3-3 proteins (RARS74LP. We present evidence indicating that when binding of R6 to 14-3-3 proteins is prevented, R6 displays hyper-glycogenic activity although is rapidly degraded by the lysosomal pathway. These results define binding to 14-3-3 proteins as an additional pathway in the control of the glycogenic properties of R6.

  13. Structural basis for rational design of inhibitors targeting Trypanosoma cruzi sterol 14α-demethylase: two regions of the enzyme molecule potentiate its inhibition.

    Science.gov (United States)

    Friggeri, Laura; Hargrove, Tatiana Y; Rachakonda, Girish; Williams, Amanda D; Wawrzak, Zdzislaw; Di Santo, Roberto; De Vita, Daniela; Waterman, Michael R; Tortorella, Silvano; Villalta, Fernando; Lepesheva, Galina I

    2014-08-14

    Chagas disease, which was once thought to be confined to endemic regions of Latin America, has now gone global, becoming a new worldwide challenge with no cure available. The disease is caused by the protozoan parasite Trypanosoma cruzi, which depends on the production of endogenous sterols, and therefore can be blocked by sterol 14α-demethylase (CYP51) inhibitors. Here we explore the spectral binding parameters, inhibitory effects on T. cruzi CYP51 activity, and antiparasitic potencies of a new set of β-phenyl imidazoles. Comparative structural characterization of the T. cruzi CYP51 complexes with the three most potent inhibitors reveals two opposite binding modes of the compounds ((R)-6, EC50=1.2 nM, vs (S)-2/(S)-3, EC50=1.0/5.5 nM) and suggests the entrance into the CYP51 substrate access channel and the heme propionate-supporting ceiling of the binding cavity as two distinct areas of the protein that enhance molecular recognition and therefore could be used for the development of more effective antiparasitic drugs. PMID:25033013

  14. First direct measurement of the $^{11}$C($\\alpha$, p)$^{14}$N stellar reaction by an extended thick-target method

    CERN Document Server

    Hayakawa, S; Kahl, D; Yamaguchi, H; Binh, D N; Hashimoto, T; Wakabayashi, Y; He, J J; Iwasa, N; Kato, S; Komatsubara, T; Kwon, Y K; Teranishi, T

    2016-01-01

    The $^{11}$C($\\alpha$, p) reaction is an important $\\alpha$-induced reaction competing with $\\beta$-limited hydrogen-burning processes in high-temperature explosive stars. We directly measured its reaction cross sections both for the ground-state transition ($\\alpha$, $p_{0}$) and the excited-state transitions ($\\alpha$, $p_{1}$) and ($\\alpha$, $p_{2}$) at relevant stellar energies 1.3 - 4.5 MeV by an extended thick-target method featuring time of flight for the first time. We revised the reaction rate by numerical integration including the ($\\alpha$, $p_{1}$) and ($\\alpha$, $p_{2}$) contributions and also low-lying resonances of ($\\alpha$, $p_{0}$) using both the present and the previous experimental data which were totally neglected in the previous compilation works. The present total reaction rate lies between the previous ($\\alpha$, $p_{0}$) rate and the total rate of the Hauser-Feshbach statistical model calculation, which is consistent with the relevant explosive hydrogen-burning scenarios such as the $...

  15. Simulation of swift boron clusters traversing amorphous carbon foils

    OpenAIRE

    Heredia Ávalos, Santiago; Abril Sánchez, Isabel; Denton Zanello, Cristian D.; García Molina, Rafael

    2007-01-01

    We use a simulation code to study the interaction of swift boron clusters (Bn+, n=2–6, 14) with amorphous carbon foils. We analyze different aspects of this interaction, such as the evolution of the cluster structure inside the target, the energy and angle distributions at the detector or the stopping power ratio. Our simulation code follows in detail the motion of the cluster fragments through the target and in the vacuum until reaching a detector, taking into account the following interacti...

  16. A Nano-MgO and Ionic Liquid-Catalyzed ‘Green’ Synthesis Protocol for the Development of Adamantyl-Imidazolo-Thiadiazoles as Anti-Tuberculosis Agents Targeting Sterol 14α-Demethylase (CYP51)

    Science.gov (United States)

    Anusha, Sebastian; CP, Baburajeev; Mohan, Chakrabhavi Dhananjaya; Mathai, Jessin; Rangappa, Shobith; Mohan, Surender; Chandra; Paricharak, Shardul; Mervin, Lewis; Fuchs, Julian E.; M, Mahedra; Bender, Andreas; Basappa; Rangappa, Kanchugarakoppal S.

    2015-01-01

    In this work, we describe the ‘green’ synthesis of novel 6-(adamantan-1-yl)-2-substituted-imidazo[2,1-b][1,3,4]thiadiazoles (AITs) by ring formation reactions using 1-(adamantan-1-yl)-2-bromoethanone and 5-alkyl/aryl-2-amino1,3,4-thiadiazoles on a nano material base in ionic liquid media. Given the established activity of imidazothiadiazoles against M. tuberculosis, we next examined the anti-TB activity of AITs against the H37Rv strain using Alamar blue assay. Among the tested compounds 6-(adamantan-1-yl)-2-(4-methoxyphenyl)imidazo[2,1-b][1,3,4]thiadiazole (3f) showed potent inhibitory activity towards M. tuberculosis with an MIC value of 8.5 μM. The inhibitory effect of this molecule against M. tuberculosis was comparable to the standard drugs such as Pyrazinamide, Streptomycin, and Ciprofloxacin drugs. Mechanistically, an in silico analysis predicted sterol 14α-demethylase (CYP51) as the likely target and experimental activity of 3f in this system corroborated the in silico target prediction. In summary, we herein report the synthesis and biological evaluation of novel AITs against M. tuberculosis that likely target CYP51 to induce their antimycobacterial activity. PMID:26470029

  17. A Nano-MgO and Ionic Liquid-Catalyzed 'Green' Synthesis Protocol for the Development of Adamantyl-Imidazolo-Thiadiazoles as Anti-Tuberculosis Agents Targeting Sterol 14α-Demethylase (CYP51).

    Science.gov (United States)

    Anusha, Sebastian; Cp, Baburajeev; Mohan, Chakrabhavi Dhananjaya; Mathai, Jessin; Rangappa, Shobith; Mohan, Surender; Chandra; Paricharak, Shardul; Mervin, Lewis; Fuchs, Julian E; M, Mahedra; Bender, Andreas; Basappa; Rangappa, Kanchugarakoppal S

    2015-01-01

    In this work, we describe the 'green' synthesis of novel 6-(adamantan-1-yl)-2-substituted-imidazo[2,1-b][1,3,4]thiadiazoles (AITs) by ring formation reactions using 1-(adamantan-1-yl)-2-bromoethanone and 5-alkyl/aryl-2-amino1,3,4-thiadiazoles on a nano material base in ionic liquid media. Given the established activity of imidazothiadiazoles against M. tuberculosis, we next examined the anti-TB activity of AITs against the H37Rv strain using Alamar blue assay. Among the tested compounds 6-(adamantan-1-yl)-2-(4-methoxyphenyl)imidazo[2,1-b][1,3,4]thiadiazole (3f) showed potent inhibitory activity towards M. tuberculosis with an MIC value of 8.5 μM. The inhibitory effect of this molecule against M. tuberculosis was comparable to the standard drugs such as Pyrazinamide, Streptomycin, and Ciprofloxacin drugs. Mechanistically, an in silico analysis predicted sterol 14α-demethylase (CYP51) as the likely target and experimental activity of 3f in this system corroborated the in silico target prediction. In summary, we herein report the synthesis and biological evaluation of novel AITs against M. tuberculosis that likely target CYP51 to induce their antimycobacterial activity.

  18. A Nano-MgO and Ionic Liquid-Catalyzed 'Green' Synthesis Protocol for the Development of Adamantyl-Imidazolo-Thiadiazoles as Anti-Tuberculosis Agents Targeting Sterol 14α-Demethylase (CYP51.

    Directory of Open Access Journals (Sweden)

    Sebastian Anusha

    Full Text Available In this work, we describe the 'green' synthesis of novel 6-(adamantan-1-yl-2-substituted-imidazo[2,1-b][1,3,4]thiadiazoles (AITs by ring formation reactions using 1-(adamantan-1-yl-2-bromoethanone and 5-alkyl/aryl-2-amino1,3,4-thiadiazoles on a nano material base in ionic liquid media. Given the established activity of imidazothiadiazoles against M. tuberculosis, we next examined the anti-TB activity of AITs against the H37Rv strain using Alamar blue assay. Among the tested compounds 6-(adamantan-1-yl-2-(4-methoxyphenylimidazo[2,1-b][1,3,4]thiadiazole (3f showed potent inhibitory activity towards M. tuberculosis with an MIC value of 8.5 μM. The inhibitory effect of this molecule against M. tuberculosis was comparable to the standard drugs such as Pyrazinamide, Streptomycin, and Ciprofloxacin drugs. Mechanistically, an in silico analysis predicted sterol 14α-demethylase (CYP51 as the likely target and experimental activity of 3f in this system corroborated the in silico target prediction. In summary, we herein report the synthesis and biological evaluation of novel AITs against M. tuberculosis that likely target CYP51 to induce their antimycobacterial activity.

  19. A Nano-MgO and Ionic Liquid-Catalyzed 'Green' Synthesis Protocol for the Development of Adamantyl-Imidazolo-Thiadiazoles as Anti-Tuberculosis Agents Targeting Sterol 14α-Demethylase (CYP51).

    Science.gov (United States)

    Anusha, Sebastian; Cp, Baburajeev; Mohan, Chakrabhavi Dhananjaya; Mathai, Jessin; Rangappa, Shobith; Mohan, Surender; Chandra; Paricharak, Shardul; Mervin, Lewis; Fuchs, Julian E; M, Mahedra; Bender, Andreas; Basappa; Rangappa, Kanchugarakoppal S

    2015-01-01

    In this work, we describe the 'green' synthesis of novel 6-(adamantan-1-yl)-2-substituted-imidazo[2,1-b][1,3,4]thiadiazoles (AITs) by ring formation reactions using 1-(adamantan-1-yl)-2-bromoethanone and 5-alkyl/aryl-2-amino1,3,4-thiadiazoles on a nano material base in ionic liquid media. Given the established activity of imidazothiadiazoles against M. tuberculosis, we next examined the anti-TB activity of AITs against the H37Rv strain using Alamar blue assay. Among the tested compounds 6-(adamantan-1-yl)-2-(4-methoxyphenyl)imidazo[2,1-b][1,3,4]thiadiazole (3f) showed potent inhibitory activity towards M. tuberculosis with an MIC value of 8.5 μM. The inhibitory effect of this molecule against M. tuberculosis was comparable to the standard drugs such as Pyrazinamide, Streptomycin, and Ciprofloxacin drugs. Mechanistically, an in silico analysis predicted sterol 14α-demethylase (CYP51) as the likely target and experimental activity of 3f in this system corroborated the in silico target prediction. In summary, we herein report the synthesis and biological evaluation of novel AITs against M. tuberculosis that likely target CYP51 to induce their antimycobacterial activity. PMID:26470029

  20. Preparation of actinide targets by electrodeposition

    Science.gov (United States)

    Trautmann, N.; Folger, H.

    1989-10-01

    Actinide targets with varying thicknesses on different substrates have been prepared by electrodeposition either from aqueous solutions or from solutions of their nitrates in isopropyl alcohol. With these techniques the actinides can be deposited almost quantitatively on various backing materials within 15 to 30 min. Targets of thorium, uranium, neptunium, plutonium, americium, curium and californium with areal densities from almost carrier-free up to 1.4 mg/cm 2 on thin beryllium, carbon, titanium, tantalum and platinum foils have been prepared. In most cases, prior to the deposition, the actinides had to be purified chemically and for some of them, due to the limited amount of material available, recycling procedures were required. Applications of actinide targets in heavy-ion reactions are briefly discussed.

  1. Carbon-14 analysis in solidified product of non-metallic solid waste by a combination of alkaline fusion and gaseous CO2 trapping.

    Science.gov (United States)

    Ishimori, Ken-ichiro; Kameo, Yutaka; Matsue, Hideaki; Ohki, Yoshiyuki; Nakashima, Mikio; Takahashi, Kuniaki

    2011-02-01

    In order to establish a simple and rapid analytical method for (14)C in solidified products made from non-metallic low-level radioactive solid wastes such as concrete, mortar and glass by melting treatment, a radiochemical analysis in combination with alkaline fusion as a sample decomposition method was examined. A simulated solidified product containing (14)C, which was prepared by using nuclear reaction (14)N(n, p)(14)C with thermal neutron irradiation, was analyzed by the present method to compare with a conventional radiochemical analysis using oxidizing combustion. The reproducible and quantitative recovery of (14)C from the simulated solidified product indicates that the present method is more efficient for (14)C analysis in solidified products than the conventional method using oxidizing combustion. PMID:21074999

  2. Carbon-14 activity of fallout in Araucaria angustifolia annual growth rings, from Arapoti, Parana State, Brazil; Atividade de {sup 14} C do 'fallout' em aneis anuais de crescimento de Araucaria angustifolia, de Arapoti - PR

    Energy Technology Data Exchange (ETDEWEB)

    Lisi, Claudio Sergio; Pessenda, Luiz Carlos Ruiz [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de 14 C; Tomazello Filho, Mario [Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, SP (Brazil). Dept. de Ciencias Florestais. Lab. de Dendrocronologia

    2000-07-01

    During the period of nuclear tests between 1950 and 1960, an input of artificial {sup 14} C (fallout effect) occurred in the natural reservoirs. {sup 14} C determinations in the Northern Hemisphere showed values of {delta}{sup 14} C up to 960 in the year of 1964. To determine the fallout {sup 14} C activity in Brazil, wood samples from Araucaria angustifolia (Bert.) O. Kuntze, Araucariaceae, were collected in Arapoti-PR (24 deg 11{sup S}, 49 deg 58{sup O}). The annual tree rings were selected by dendrochronology. The cellulose was extracted and its {sup 14} C activity determined by liquid scintillation method. The results showed a significant increase of the {delta} {sup 14} C up to 590 in 1965, about 60% higher than the natural activity, gradually decreasing after the end of nuclear tests. These results were correlated with those obtained in the Northen Hemisphere and will be used in the studies of CO{sub 2} mechanisms distribuition to the atmosphere and other natural reservoirs. (author)

  3. Increased accuracy of the carbon-14 D-xylose breath test in detecting small-intestinal bacterial overgrowth by correction with the gastric emptying rate

    International Nuclear Information System (INIS)

    The aim of this study was to determine whether the accuracy of 14C-D-xylose breath test for detecting bacterial overgrowth can be increased by correction with the gastric emptying rate of 14C-D-xylose. Ten culture-positive patients and ten culture-negative controls were included in the study. Small-intestinal aspirates for bacteriological culture were obtained endoscopically. A liquid-phase gastric emptying study was performed simultaneously to assess the amount of 14C-D-xylose that entered the small intestine. The results of the percentage of expired 14CO2 at 30 min were corrected with the amount of 14C-D-xylose that entered the small intestine. There were six patients in the culture-positive group with a 14CO2 concentration above the normal limit. Three out of four patients with initially negative results using the uncorrected method proved to be positive after correction. All these three patients had prolonged gastric emptying of 14C-D-xylose. When compared with cultures of small-intestine aspirates, the sensitivity and specificity of the uncorrected 14C-D-xylose breath test were 60% and 90%, respectively. In contrast, the sensitivity and specificity of the corrected 14C-D-xylose breath test improved to 90% and 100%, respectively. (orig./MG)

  4. Synthesis and purification of carbon-14 labelled 1, 1-hexamethylene-bis (5-(4-chlorophenyl)biguanide) (chlorhexidine, 'Hibitane')

    Energy Technology Data Exchange (ETDEWEB)

    Burns, J. (Imperial Chemical Industries Ltd., Macclesfield (UK). Pharmaceuticals Div.)

    1982-10-01

    Two syntheses of (/sup 14/C) chlorhexidine ('Hibitane') with the label specifically incorporated in two separate molecular positions are described. Ring labelled chlorhexidine prepared from p-chloro(U-/sup 14/C)aniline was obtained with a molar specific activity of 27.9 mCi/mmol. Chain labelled material, where the /sup 14/C label was incorporated in the 1 and 6 positions of the hexamethylene bridge, was prepared from (1, 6 /sup 14/C)-adiponitrile, with a molar specific activity of 11.5 mCi/mmol. Several methods of purification are described.

  5. Soil and vegetation dynamics in a forest-savannah boundary in Southern Amazon state during the holocene, using 14C dating and stable carbon isotopes of soil organic matter

    International Nuclear Information System (INIS)

    This work presents a comparative study between organic soil horizons formed in depressions, distant ca. 500 meters from each sampling site, in a forest/savannah boundary in the Southern Amazon Basin. The influence of the paleovegetation and soil dynamics, based on carbon isotope (12C, 13C, 14C) data of soil organic matter (SOM) was evaluated. The soils were classified as Dystropept (Cambissolo) and were considered as clayey. The total organic carbon contents decreased from the surface to deeper parts of the soils profiles. At deeper parts of the soil profiles in the savannah site, between 100 cm and 30 cm, the δ13C values characterized the influence of C4 plants (around -18,0 per mille). From about 20 cm to the surface the δ13C values characterized the mixture of C3 and C4 plants. The soil δ13C values in the forest site ranged from -25,0 per mille at deeper parts of the profile to -26,0 per mille in the surface, characterizing the dominance of C3 plants in this location. 13C and 14C data from soil samples indicated a predominance of C3 plants in the early Holocene. From ca. 7000 to 3000 years BP the influence of C4 plants increased, characterizing a savannah expansion probably related to a drier climate in the region. Since 3000 years 14C BP, the carbon isotope data suggest the forest expansion, probably due to a return to wetter climate. 14C data in the 40-50 cm and 100 cm soil depth were contemporary, showing no difference on the soil organic matter deposition in the savannah and in the forest locations. (author)

  6. ENVIRONMENTAL BIODEGRADABILITY OF [14C] SINGLE-WALLED CARBON NANOTUBESBY TRAMETES VERSICOLOR AND NATURAL MICROBIAL CULTURES FOUND IN NEWBEDFORD HARBOR SEDIMENT AND AERATED WASTEWATER TREATMENT PLANT SLUDGE

    Science.gov (United States)

    Little is known about environmental biodegradability or biotransformations of single-walled carbon nanotubes (SWNT). Because of their strong association with aquatic organic matter, detailed knowledge of the ultimate fate and persistence of SWNT requires investigation of possible...

  7. Processing ix spent resin waste for C-14 isotope recovery

    International Nuclear Information System (INIS)

    A process developed at Ontario Hydro for recovering carbon-14 (C-14) from spent ion exchange resin wastes is described. Carbon-14 is an undesirable by-product of CANDU1 nuclear reactor operation. It has an extremely long (5730 years) half-life and can cause dosage to inhabitants by contact, inhalation, or through the food cycle via photosynthesis. Release of carbon-14 to the environment must be minimized. Presently, all the C-14 produced in the Moderator and Primary Heat Transport (PHT) systems of the reactor is effectively removed by the respective ion exchange columns, and the spent ion exchange resins are stored in suitably engineered concrete structures. Because of the large volumes of spent resin waste generated each year this method of disposal by long term storage tends to be uneconomical; and may also be unsatisfactory considering the long half-life of the C-14. However, purified C-14 is a valuable commercial product for medical, pharmaceutical, agricultural, and organic chemistry research. Currently, commercial C-14 is made artificially in research reactors by irradiating aluminum nitride targets for 4.5 years. If the C-14 containing resin waste can be used to reduce this unnecessary production of C-14, the total global build-up of this radioactive chemical can be reduced. There is much incentive in removing the C-14 from the resin waste to reduce the volume of C-14 waste, and also in purifying the recovered C-14 to supply the commercial market. The process developed by Ontario Hydro consists of three main steps: C-14 removal from spent resins, enrichment of recovered C-14, and preparation of final product. Components of the process have been successfully tested at Ontario Hydro's Research Division, but the integration of the process is yet to be demonstrated. A pilot scale plant capable of processing 4 m3 of spent resins annually is being planned for demonstrating the technology. The measured C-14 activity levels on the spent resins ranged from 47-213 Ci

  8. Synthesis of triple (13C2, 15N), single (14C), and double (14C2) labeled trimetrexate

    International Nuclear Information System (INIS)

    A method was developed for the synthesis of triple (13C2, 14N) labeled trimetrexate. A method for single carbon-14 labeled synthesis is also described. Modifications of the triple labeled synthesis with carbon-14 produced a doubled carbon-14 labeled trimetrexate. (author)

  9. Target preparation at the ANTARES AMS Centre

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, G.E.; Hua, Q.; Fink, D.; Hotchkis, M.A.C.; Lawson, E.M. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    The Antares Accelerator Mass Spectroscopy Centre at ANSTO has two chemistry labs dedicated to preparing targets for measurement. Target preparation encompasses a variety of activities ranging from the curation of incoming samples to the numerous steps involved in the purification and processing of dissimilar samples. One of the two laboratories is set up for the physical and chemical pretreatment of {sup 14}C samples. Treatments include cleaning by sonification, sorting, grinding and sieving, and chemical treatments such as the standard AAA treatment, and solvent extraction. Combustion and graphitization are also carried out in this laboratory. The second laboratory is a clean room and is dedicated to the combustion, hydrolysis and graphitization of {sup 14}C samples as well as the process of the targets for the other isotopes. Combustion is achieved by heating the sample to 900 deg C in the presence of CuO, the resulting gas is purified by passing over Ag and Cu wire at 600 deg C. Graphitization is carried out by reducing the CO{sub 2} with an iron catalyst (600 deg C) in the presence of zinc (400 deg C) and a small amount of hydrogen. Samples such as charcoal, shell bone, wood, sediment, seawater and groundwater, containing 0.3-1 mg or more of original carbon, are processed routinely for radiocarbon analysis. The current {sup 14}C chemistry background for 1 mg carbon is {approx} 0.3 percent of modern carbon (pMC) enabling us to date materials up to 45 000 BP. Samples of 0.5 - 3 mg carbon or more are routinely performed with a precision < 1% At present, procedures are being tested for the treatment of samples containing a minimum of 20 {mu}g original carbon. Such small samples sre more likely to be affected by contamination with modern carbon. These laboratories are also being expanded to cater for the processing of a variety of samples for the measurement of other isotopes, ie {sup 129}I, {sup 10}Be, {sup 36}CI and {sup 26}Al. Initial tests for the extraction of

  10. Applications of radiocarbon in the terrestrial carbon cycle and related research advances%14C在陆地生态系统碳循环研究中的应用及进展

    Institute of Scientific and Technical Information of China (English)

    熊晓虎; 周卫健; 杜花; 程鹏; 吴书刚; 牛振川; 卢雪峰

    2016-01-01

    深刻理解陆地生态系统碳循环有助于提高未来气候预测的准确性。14C是陆地生态系统碳循环研究中广泛应用的重要工具,本文对14C在土壤有机碳周转时间和平均停留时间的评估、陆地生态系统释放CO2的源解析、河流有机碳的源解析及陆地生态系统碳循环对气候变化和土地利用的响应等四个方面的应用及进展进行了细致的介绍,最后展望了14C应用于陆地碳循环研究发展趋势,并对国内相关研究的开展提出了几点建议。%Background, aim, and scope Terrestrial ecosystems are one of the main sources and sinks of atmospheric CO2 now, however, it is not clear whether it will become a net source or sink in the future under the inlfuence of climate change and human activities. Radiocarbon is an important and widely used tool in the research of terrestrial carbon cycle. In this paper, the research progress in recent years were reviewed and divided in four parts: the calculation of turnover time and mean residence time of soil organic carbon, partitioning sources of CO2 derived from terrestrial ecosystem, partitioning sources of lfuvial organic carbon and the response of terrestrial carbon cycle to climate change and land use. The expanded applications of radiocarbon in terrestrial carbon cycle in future and the deifciencies of related research in China were also discussed.Materials and methods We mainly reviewed the literature those use radiocarbon with alternative method (model) to evaluate the turnover of soil organic carbon, partition sources of different types of C in terrestrial ecosystem or catch the response of terrestrial carbon cycle to climate change and land use, then, we made comparisons between these methods (models).Results The turnover time of soil organic carbon (SOC) is a measuring of its mixing or refresh rate, and is the time it would take for the reservoir to completely empty if there were no further inputs. And the mean

  11. Baryon emission at target rapidities in Si+Al,Cu,Au collisions at 14.6AGeV/c and Au+Au collisions at 11.7AGeV/c

    International Nuclear Information System (INIS)

    We report measurements of proton emission at target rapidities for minimum bias and central collisions of 14.6AGeV/c 28Si with Al, Cu, and Au nuclei as well as minimum bias and central collisions of 11.7AGeV/c 197Au with Au nuclei. Results for deuteron emission are also reported for the Si+Au reaction. The spectra span the laboratory angular range of 50 degree ≤θ≤130 degree and kinetic energy range of 40MeV≤Ekin≤225MeV. Inverse slopes of proton spectra and proton dN/dη values in the kinetic energy range 50MeV≤Ekin≤110MeV are reported. The inverse slopes are 40 - 80 MeV for the various systems, generally increasing with increasing pseudorapidity. The dN/dη values for A+A collisions within the restricted kinetic energy interval are compared to those for protons from p+Au in the literature. All pseudorapidity distributions have very similar shapes. The experimental results have been compared to the predictions of the nucleon-nucleon collision models ARC and RQMD. The predictions made by these two models for the distribution of protons at target rapidities are very similar to each other. However, there are significant differences between the model predictions and the experimental results in the details of the spectral slopes and the proton yields for different trigger conditions. copyright 1997 The American Physical Society

  12. Radiochemical investigations of 177Lu-DOTA-8-Aoc-BBN[7-14]NH2: an in vitro/in vivo assessment of the targeting ability of this new radiopharmaceutical for PC-3 human prostate cancer cells

    International Nuclear Information System (INIS)

    Bombesin (BBN), a 14 amino acid peptide, is an analogue of human gastrin releasing peptide (GRP) that binds to GRP receptors (GRPr) with high affinity and specificity. The GRPr is over expressed on a variety of human cancer cells including prostate, breast, lung, and pancreatic cancers. The specific aim of this study was to identify a BBN analogue that can be radiolabeled with 177Lu and maintains high specificity for GRPr positive prostate cancer tumors in vivo. A preselected synthetic sequence via solid phase peptide synthesis (SPPS) was designed to produce a DOTA-BBN (DOTA 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) conjugate with the following general structure: DOTA-X-Q-W-A-V-G-H-L-M-(NH2), where the spacer group, X = ω-NH2(CH2)7COOH (8-Aoc). The BBN-construct was purified by reversed phase-HPLC (RP-HPLC). Electrospray Mass Spectrometry (ES-MS) was used to characterize both metallated and non-metallated BBN-conjugates. The new DOTA-conjugate was metallated with 177Lu(III)Cl3 or non-radioactive Lu(III)Cl3. The 177Lu(III)- and non-radiolabeled Lu(III)-conjugates exhibit the same retention times under identical RP-HPLC conditions. The 177Lu-DOTA-8-Aoc-BBN[7-14]NH2 conjugate was found to exhibit optimal pharmacokinetic properties in CF-1 normal mice. In vitro and in vivo models demonstrated the ability of the 177Lu-DOTA-8-Aoc-BBN[7-14]NH2 conjugate to specifically target GRP receptors expressed on PC-3 human prostate cancer cells

  13. Biodegradation of poly(butylene succinate) powder in a controlled compost at 58°C evaluated by naturally-occurring carbon 14 amounts in evolved CO(2) based on the ISO 14855-2 method.

    Science.gov (United States)

    Kunioka, Masao; Ninomiya, Fumi; Funabashi, Masahiro

    2009-10-01

    The biodegradabilities of poly(butylene succinate) (PBS) powders in a controlled compost at 58 degrees C have been studied using a Microbial Oxidative Degradation Analyzer (MODA) based on the ISO 14855-2 method, entitled "Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions-Method by analysis of evolved carbon dioxide-Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test". The evolved CO(2) was trapped by an additional aqueous Ba(OH)(2) solution. The trapped BaCO(3) was transformed into graphite via a serial vaporization and reduction reaction using a gas-tight tube and vacuum manifold system. This graphite was analyzed by accelerated mass spectrometry (AMS) to determine the percent modern carbon [pMC (sample)] based on the (14)C radiocarbon concentration. By using the theory that pMC (sample) was the sum of the pMC (compost) (109.87%) and pMC (PBS) (0%) as the respective ratio in the determined period, the CO(2) (respiration) was calculated from only one reaction vessel. It was found that the biodegradabilities determined by the CO(2) amount from PBS in the sample vessel were about 30% lower than those based on the ISO method. These differences between the ISO and AMS methods are caused by the fact that part of the carbons from PBS are changed into metabolites by the microorganisms in the compost, and not changed into CO(2). PMID:20057944

  14. Effect of Ginkgo Biloba Extract on The Toxicity and Distribution of 14C-Carbon Tetrachloride in Adult Male Albino Rats

    International Nuclear Information System (INIS)

    The present study was conducted to investigate the possibility of whether the standardized extract of Ginkgo biloba (EGb-761) has a protective and therapeutic effect on the toxicity and distribution of 14C-CCl4 in different brain areas (cerebellum, striatum, cerebral cortex) of adult male albino rats for determination of distribution of 14C-CCl4 and monoamine contents (dopamine (DA), norepinephrine (NE) and serotonin (5- HT)) and also estimation of serum total antioxidant capacity (TAC) in adult male albino rat. The i.p. injection of 14C-CCl4 (1ml/kg) resulted in increase in the activity of counted 14C in all tested brain areas all over the experimental period. The treatment with EGb-761 (200 mg/kg) pre and post 1'4C-CCl4 injection resulted in a significant reduction (P14C in tested areas. The maximum reduction was observed in cerebral cortex on 1st day (-40.91%) after pre-treatment with EGb-761. The treatment with CCl4 (1ml/kg) resulted in a significant reduction (P4 . The pre and post-treatment with EGb-761 ameliorated the effect of CCl4 in all tested brain areas throughout the experimental period. This may be due to the free radical scavenger property of its constituents. Data obtained could recommend that EGb-761 has a protective and therapeutic effect against toxicity produced by CCl4 .

  15. Building resilience to overheating into UK 1960s hospital buildings within the constraint of the national carbon reduction target: adaptive strategies

    OpenAIRE

    Short, C. Alan; Lomas, Kevin; Giridharan, Renganathan; Fair, Alistair

    2012-01-01

    The National Health Service (NHS) Estate in England includes 18.83 Mm2 of acute hospital accommodation, distributed across 330 sites. Vulnerability to overheating is clear with 15,000 excess deaths occurring nationally during the July 2003 heatwave. The installation of mechanical cooling in existing hospitals appears to be the inevitable recommendation from NHS patient safety risk assessments but the carbon implications would undermine the NHS Carbon Reduction Strategy. NHS CO2 emissions cons...

  16. Comportement des déchets graphite en situation de stockage : Relâchement et répartition des espèces organiques et inogarniques du carbone 14 et du tritium en milieu alcalin

    OpenAIRE

    Vende, Ludivine

    2012-01-01

    23000 tons of graphite wastes will be generated during dismantling of the first generation of French reactors (9 gas cooled reactors). These wastes are classified as Long Lived Low Level wastes (LLW-LL). As requested by the law, the French National Radioactive Waste Management Agency (Andra) is studying concepts of low-depth disposals.In this work we focus on carbon 14, the main long-lived radionuclide in graphite waste (5730y), but also on tritium, which is the main contributor to the radioa...

  17. Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1112, LB4865_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1112, LB4865_V)' providing data by calculation of mass density in the single-phase region(s) from low-pressure dilatometric measurements of the molar excess volume at variable mole fraction and constant temperature.

  18. Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1211, LB4862_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Dimethyl carbonate C3H6O3 + C10H22O5 2,5,8,11,14-Pentaoxapentadecane (VMSD1211, LB4862_V)' providing data from direct low-pressure dilatometric measurement of molar excess volume at variable mole fraction and constant temperature.

  19. 一种企业集团内部碳排放权年度总量目标的确定方法%An Efficient Method for Determining the Total Annual Target of Enterprise Group's Carbon Emissions

    Institute of Scientific and Technical Information of China (English)

    杨丽; 曹明; 王勇

    2015-01-01

    碳排放权年度总量目标的确定是建立集团企业内部碳排放权交易制度首先应解决的问题.在分析排污权总量确定方法的基础上,提出了基于环境负荷控制方程的集团企业碳排放权确定方法.该方法将环境保护与企业绩效联系在一起,可以帮助企业确定最佳年度排放总量,在保证企业盈利能力的同时达到国家对企业的减排要求.%The determination of total annual targets of carbon emission is the most important task to establish enterprise group's internal carbon emissions trading system. Based on the determination method of analyzing total emissions, some reasonable suggestion have been proposed for the total annual target of enterprise group's internal carbon emissions determination methods. This method connects the environment protection with firm performance to find the best total annual emissions for the enterprise, meeting profit-making and the requirements of reduction.

  20. A model-based interpretation of low frequency changes in the carbon cycle during the last 120,000 years and its implications for the reconstrucion of atmospheric D14C and the 14C production rates estimates

    OpenAIRE

    Köhler, Peter; R. Muscheler; Fischer, Hubertus

    2006-01-01

    We use the ocean/atmosphere/biosphere box model of the global carbon cycle BICYCLE (Köhler et al., 2005) to reproduce low frequency changes in atmospheric CO2 as seen in Antarctic ice cores during the last glacial cycle (120,000 years) (Köhler et al., 2006). We force the model forward in time by various paleo-climatic records derived from ice and sediment cores. The simulation results of our proposed scenario match a compiled CO2 record from various ice cores with high accuracy (r2 = 0.89). T...

  1. Simulations of the global carbon cycle and anthropogenic CO{sub 2} transient. Final report, September 15, 1993--September 14, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Sarmiento, J.L.; Pacala, S.W.

    1998-06-01

    The primary accomplishment of this research was the development of an ocean biogeochemistry model for the carbon cycle, and the application of this model to studies of anthropogenic CO{sub 2} uptake and the global carbon cycle. The model has been used to study the oceanic uptake that would occur if future atmospheric CO{sub 2} were to be stabilized with the ocean circulation remaining constant. The authors also modeled how oceanic uptake would be affected by changes in ocean circulation that are predicted to occur due to global warming. The research resulted in 21 publications, and an additional 5 papers either in press or in preparation. The accomplishments of this research served as the foundation on which the Carbon Modeling Consortium was built. The CMC is a NOAA funded collaborative program involving principal investigators from various NOAA laboratories and universities. It has the goal of developing techniques to monitor the global carbon cycle on land as well as the ocean, and to predict its future course.

  2. Role Of Ginkgo BILOBA Extract In Ameliorating The Toxicity And Distribution Of 14C-Carbon Tetrachloride In Some Brain Areas Of Adult Male Albino Rats

    International Nuclear Information System (INIS)

    The present study was conducted to investigate the protective and therapeutic effect of the standardized extract of Ginkgo biloba (EGb-761) on distribution of14C-CCl4 in different brain areas (hippocampus, brain stem and hypothalamus) and its toxicity using the determination of monoamine contents (dopamine (DA), norepinephrine (NE) and serotonin (5-HT)) as well as estimation of serum nitric oxide (NO) and malondialdehyde (MDA) in adult male albino rat. The i.p. injection of14C-CCl4 (1 ml/kg) resulted in increase in the activity of 14C amount in all tested brain areas during experimental period. The treatment with EGb-761 (200 mg/kg) pre and post 14C-CCl4 treatment resulted in a significant reduction (P14C amount in areas under investigation. The maximum reduction was recorded in hypothalamus on 3rd day (-49.28%) after pre-treatment with EGb-761. The treatment with CCl4 (1ml/kg) resulted in a significant reduction (P4. The pre and post-treatment with EGb-761 ameliorated the effect of CCl4 in all tested brain areas throughout the experimental period, which might be due to the free radical scavenger property of its constituents. The data obtained could recommend that EGb-761 has a protective and therapeutic effect against toxicity produced by CCl4.

  3. Biomarker and carbon isotope constraints (δ{sup 13}C, Δ{sup 14}C) on sources and cycling of particulate organic matter discharged by large Siberian rivers draining permafrost areas

    Energy Technology Data Exchange (ETDEWEB)

    Winterfeld, Maria

    2014-08-15

    Circumpolar permafrost soils store about half of the global soil organic carbon pool. These huge amounts of organic matter (OM) could accumulate due to low temperatures and water saturated soil conditions over the course of millennia. Currently most of this OM remains frozen and therefore does not take part in the active carbon cycle, making permafrost soils a globally important carbon sink. Over the last decades mean annual air temperatures in the Arctic increased stronger than the global mean and this trend is projected to continue. As a result the permafrost carbon pool is under climate pressure possibly creating a positive climate feedback due to the thaw-induced release of greenhouse gases to the atmosphere. Arctic warming will lead to increased annual permafrost thaw depths and Arctic river runoff likely resulting in enhanced mobilization and export of old, previously frozen soil-derived OM. Consequently, the great arctic rivers play an important role in global biogeochemical cycles by connecting the large permafrost carbon pool of their hinterlands with the arctic shelf seas and the Arctic Ocean. The first part of this thesis deals with particulate organic matter (POM) from the Lena Delta and adjacent Buor Khaya Bay. The Lena River in central Siberia is one of the major pathways translocating terrestrial OM from its southernmost reaches near Lake Baikal to the coastal zone of the Laptev Sea. The permafrost soils from the Lena catchment area store huge amounts of pre-aged OM, which is expected to be remobilized due to climate warming. To characterize the composition and vegetation sources of OM discharged by the Lena River, the lignin phenol and carbon isotopic composition (δ{sup 13}C and Δ{sup 14}C) in total suspended matter (TSM) from surface waters, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex) were analyzed. The lignin compositions of these samples are

  4. The Path of Carbon in Photosynthesis XIII. pH Effects in C{sup 14}O{sub 2} Fixation by Scenedesmus

    Science.gov (United States)

    Ouellet, C.; Benson, A. A.

    1951-10-23

    The rates of photosynthesis and dark fixation of C{sup 14}O{sub 2} in Scenedesmus have been compared in dilute phosphate buffers of 1.6 to 11.4 pH; determination of C{sup 14} incorporation into the various products shows enhancement of uptake in an acid medium into sucrose, polysaccharides, alanine and serine, in an alkaline medium into malic asparctic acids. kinetic experiments at extreme pH values suggest that several paths are available for CO{sub 2} assimilation. A tentative correlation of the results with the pH optima of some enzymes and resultant effects upon concentrations of intermediates is presented.

  5. 促进区域产业有序转移与协调发展的碳减排目标设计%Target Design on Carbon Reduction of Promoting Regional Industrial Transfer Orderly and Coordinated Development

    Institute of Scientific and Technical Information of China (English)

    成艾华; 魏后凯

    2013-01-01

    当前,在扩大内需、转变经济发展方式的大背景下,跨区域产业转移已成为中国区域政策中促进区域协调发展的重要手段.如何根据中国各区域碳排放的差异性,合理设计有差别的碳减排目标,促进区域产业有序转移与协调发展,是当前需要考虑的一个重要战略问题.本文首先采用工业部门市场份额指标来反映地区产业转移状况,并按产业转移情况和工业化水平把中国划分为净转入、净转出和其他中西部三类区域;然后运用改进的LMDI模型,从碳排放系数、碳排放强度、经济结构及经济规模四个方面对不同区域碳排放效应进行分解,明确了不同区域碳排放的差异特征.在此基础上,根据未来中国区域碳减排政策应坚持“共同而有区别的责任原则”,建立了新的区域碳减排指标分配框架,即对净转入、净转出和其他中西部三类区域分别实行以结构调整为主的强制减排、以降低能源强度为主的强制减排和发展减排的差异化目标,促进东部地区产业转型升级与中西部地区跨越式绿色发展.%In the background of expanding domestic demand and changing the mode of economic development, the regional industry transference has become one important method of Chinese regional policies which focused on regional coordinating development. How to design reasonable and considerable carbon emission reduction targets depending on the difference of regional carbon diversity has become a significant strategy of Chinese development, and the successful targets also can promote industry transference orderly and regional coordinating development fairly. In this paper, we used industry market share index to reflect the regional industry transference status, and divided Chinese regions into the area of transfer into, the area of transfer out, and the area of other middle and west places based on Chinese status of regional industry transference and

  6. The chemical nature of the carbon-14- labelled organic matter released into soil from growing wheat roots. Effects of soil micro-organisms

    International Nuclear Information System (INIS)

    Individual wheat plants were grown in a sandy soil under an atmosphere of 14CO2 for 21 days with the plant roots maintained under sterile or non-sterile conditions. A comparison has been made of the chemical nature of the 14C-labelled organic matter present in root-free soil from the sterile and non-sterile treatments, based on solubility, molecular size and ion-exchange chromatography of soil extracts and acid hydrolysates of whole soil. There was little difference between sterile and non-sterile soils for the values from any of these determinations. It is proposed that a major part of the organic 14C present in soils from both treatments resulted from autolysis of root tissue, particularly in localized zones where low water availability may have limited microbial decomposition of sugars and amino acids released from the roots. About 15% of the 14C in both soil treatments was present in humic acid fractions with a molecular weight, estimated from ultrafiltration of >5X104. These experiments show that there can be a significant formation of soil organic matter during active root growth, much of it directly from root tissue without the intervention of soil microflora or microfauna. Such reactions would be important in nutrient cycling in permanent pastures and forests, and in the interchange of nutrients in grass/legume associations. (author)

  7. Preparation of a Lipopolysaccharide from Escherichia coli 01lla, 01llb, k58: h21 bacterial wall, labeled with carbon-14

    International Nuclear Information System (INIS)

    A brief description of the morphological and chemical structure of Li po polysaccharides is given, as well as its occurrence in nature and its mechanisms of action. It is emphasized the usefulness for actual biochemical and biomedical research of the labeled Lipopolysaccharide. The method for the labelling, isolation and purification of 14''C-Lipopolysacchari de is described. (Author) 23 refs

  8. Comparing microfossil shell weight from two locations on the California coast to understand controls on bottom water carbonate chemistry over the past 14 ka

    Science.gov (United States)

    Downing, S. C.; Hill, T. M.; Flores, S. C.; Myhre, S.

    2009-12-01

    Foraminiferal shell weight has been utilized, primarily in planktonic foraminifera, to understand changes in seawater carbonate ion concentration in the geologic past. Such data can provide important insight into the natural and anthropogenic processes that induce variability in the pH and carbonate ion content of seawater. This study investigated shell weights of benthic foraminifera (E. hannai, U. peregrina and B. argentea) using sediment cores from two California sites: Tomales Bay (3 m water depth), a narrow estuary in Northern California, and Santa Barbara Basin (from 400 m) within the Southern California Bight. Based upon sedimentation rates derived from radiocarbon analyses and oxygen isotopic stratigraphy, the Tomales Bay core (2.95 mm/year) extends back ~1000 years b.p., and the Santa Barbara Basin record (~80 cm/ka) extends back to 16 ka b.p. In Tomales Bay, two decreases in shell weight of E. hannai correlate to historically-documented increases in rainfall (404 and 595 years b.p.). At the top of the core a decrease in shell weight and an overall decrease in E. hannai population may correlate to human impacts on the estuary, including land use changes that caused localized “acidification”. In Santa Barbara Basin, shell weight measurements of B. argentea do not exhibit significant variability; however, U. peregrina shell weights increase during the early Holocene, indicating a potential relationship between increased upwelling/productivity at the surface and optimal foraminiferal growth conditions at 400m. Both B. argentea and U. peregrina document a decrease in shell weight over the past 3ka making it difficult to ascertain any anthropogenic influence in the upper most sediments of the core. Further work is needed to understand the roles of carbonate ion content and foraminiferal growth conditions in forcing shell weight changes in benthic foraminifera.

  9. Biodegradation of Poly(butylene succinate Powder in a Controlled Compost at 58 °C Evaluated by Naturally-Occurring Carbon 14 Amounts in Evolved CO2 Based on the ISO 14855-2 Method

    Directory of Open Access Journals (Sweden)

    Masahiro Funabashi

    2009-09-01

    Full Text Available The biodegradabilities of poly(butylene succinate (PBS powders in a controlled compost at 58 °C have been studied using a Microbial Oxidative Degradation Analyzer (MODA based on the ISO 14855-2 method, entitled “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions—Method by analysis of evolved carbon dioxide—Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test”. The evolved CO2 was trapped by an additional aqueous Ba(OH2 solution. The trapped BaCO3 was transformed into graphite via a serial vaporization and reduction reaction using a gas-tight tube and vacuum manifold system. This graphite was analyzed by accelerated mass spectrometry (AMS to determine the percent modern carbon [pMC (sample] based on the 14C radiocarbon concentration. By using the theory that pMC (sample was the sum of the pMC (compost (109.87% and pMC (PBS (0% as the respective ratio in the determined period, the CO2 (respiration was calculated from only one reaction vessel. It was found that the biodegradabilities determined by the CO2 amount from PBS in the sample vessel were about 30% lower than those based on the ISO method. These differences between the ISO and AMS methods are caused by the fact that part of the carbons from PBS are changed into metabolites by the microorganisms in the compost, and not changed into CO2.

  10. The applicability of C-14 measurements in the soil gas for the assessment of leakage out of underground carbon dioxide reservoirs

    OpenAIRE

    Chałupnik Stanisław; Wysocka Małgorzata

    2014-01-01

    Poland, due to the ratification of the Kioto Protocol, is obliged to diminish the emission of greenhouse gases. One of the possible solutions of this problem is CO2 sequestration (CCS - carbon capture and storage). Such an option is a priority in the European Union. On the other hand, CO2 sequestration may be potentially risky in the case of gas leakage from underground reservoirs. The most dangerous event may be a sudden release of the gas onto the surface. Therefore, it is very important to...

  11. Synthesis, characterization and in vitro evaluation of methotrexate conjugated fluorescent carbon nanoparticles as drug delivery system for human lung cancer targeting.

    Science.gov (United States)

    Ajmal, Muhammad; Yunus, Uzma; Matin, Abdul; Haq, Noaman Ul

    2015-12-01

    Nanotechnology based cancer therapeutics have rapidly advanced towards the solution of many limitations associated with other drug delivery agents such as nonspecific distribution within the body, low water solubility and non-biocompatibility. Carbon nanoparticles have demonstrated unique properties that are useful to combat with these issues, including their properties dependent on size, high stability in different solvents, compatible size for drug delivery and ease of surface modifications. Fluorescent carbon nanoparticles with good water solubility were obtained from a carbohydrate source by acid assisted ultrasonic treatment at 35kHz for 4h. This simple and economical method can be used for large scale production. Electron microscopic, spectroscopic and thermo gravimetric analysis techniques were used to characterize these carbon nanoparticles. Functionalized CNPs were further conjugated with anticancer drug-methotrexate and used as fluorescent nano-carriers. In this research work, we determined the in vitro bioactivity of CNPs-methotrexate conjugates by lactate dehydrogenase assay, cell adhesion assay and sulforhodamine B assay in human lung carcinoma cell line (H157). The CNPs showed promising biocompatibility and CNPs-MTX conjugates demonstrated potent cytotoxic effects and high anticancer activities in human lung cancer cell line.

  12. Use of natural radioactive carbon 14C in the study of organic matter dynamic in the soil in two different environment

    International Nuclear Information System (INIS)

    The natural prairies which are distributed in the Alsace region in the north east of France occupy very large areas of lands. However, there is gradual retraction in these prairies at the expense of arable lands expansion. This has led to an ecological imbalance. The dynamic of the organic matter in the soil was studied by means of humic horizon, and sub-surface horizon found within these two systems (prairies and arable lands), using the natural radiocarbon isotope (C14) method. The study showed that changing the ecological system from prairies to agricultural system resulted in aging the organic matter. Age determination using C14 method also indicated that the activity of the organic matter within 'Ap' horizon and the horizon below was less than the activity of similar horizons in the prairies soils. The fraction of the organic matter for both types of soil and ages determination for the different part of organic using C14 method contributed to the following information: (1) the organic matter consists of compartments of various apparent ages. (2) the new components such as plant residuals, folic acids and the relatively new organic particles were small in the arable soils in comparison with prairies soils. The annual accumulation of organic matter and the speed of mineralization for these substances differ from system to another. These two factors lead to the disappearance of the new components from the cultivated lands, as a result the organic matter becomes aged. (3) the older particles within the organic matter are the residuals of hydrolysis of humic. (author)

  13. Ba(OH)/sub 2/. 8H/sub 2/O process for the removal and immobilization of carbon-14. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Haag, G.L.; Holladay, D.W.; Pitt, W.W. Jr.; Young, G.C.

    1986-01-01

    The airborne release of /sup 14/C from various nuclear facilities has been identified as a potential biohazard due to the long half-life of /sup 14/C (5730 years) and the ease with which it may be assimilated into the biosphere. At ORNL, technology has been developed for the removal and immobilization of this radionuclide. Prior studies have indicated that /sup 14/C will likely exist in the oxidized form as CO/sub 2/ and will contribute slightly to the bulk CO/sub 2/ concentration of the gas stream, which is air-like in nature (approx.300 ppM/sub v/ CO/sub 2/). The technology that has been developed utilizes the CO/sub 2/-Ba(OH)/sub 2/.8H/sub 2/O gas-solid reaction with the mode of gas-solid contacting being a fixed bed. The product, BaCO/sub 3/, possesses excellent thermal and chemical stability, prerequisites for the long-term disposal of nuclear wastes. For optimal process operation, studies have indicated that an operating window of adequate size does exist. When operating within the window, high CO/sub 2/ removal efficiency (effluent concentrations <100 ppB/sub v/), high reactant utilization (>99%), and an acceptable pressure drop across the bed (3 kPa/m at a superficial velocity of 13 cm/s) are possible. Three areas of experimental investigation are reported: (1) microscale studies on 150-mg samples to provide information concerning surface properties, kinetics, and equilibrium vapor pressures; (2) macroscale studies on large fixed beds (4.2 kg of reactant) to determine the effects of humidity, temperature, and gas flow rate upon bed pressure drop and CO/sub 2/ breakthrough; and (3) design, construction, and operation of a pilot unit capable of continuously processing a 34-m/sup 3//h (20-ft/sup 3//min) air-based gas stream.

  14. Self–activation and effect of regeneration conditions in CO2 – carbonate looping with CaO - Ca12Al14O33 sorbent

    OpenAIRE

    STENDARDO Stefano; Andersen, Lars; HERCE C

    2012-01-01

    CO2 capture by solid sorbents through uptake–regeneration cycling is a promising option for high temperature removal of CO2 from combustion gases and synthesis/fuel gases. The present study investigates the influence of regeneration atmosphere and temperature on the CO2 uptake capacity during repeated cycling of CaO–based solid sorbents. The sorbents were synthesised to contain 75 and 85 %w/w of active phase (CaO) and binder (Ca12Al14O33) and were then subjected to cycling tests with repeate...

  15. Stringent control during carbon starvation of marine Vibrio sp. strain S14: molecular cloning, nucleotide sequence, and deletion of the relA gene.

    OpenAIRE

    Flärdh, K; Axberg, T; Albertson, N H; Kjelleberg, S

    1994-01-01

    In order to evaluate the role of the stringent response in starvation adaptations of the marine Vibrio sp. strain S14, we have cloned the relA gene and generated relaxed mutants of this organism. The Vibrio relA gene was selected from a chromosomal DNA library by complementation of an Escherichia coli delta relA strain. The nucleotide sequence contains a 743-codon open reading frame that encodes a polypeptide that is identical in length and highly homologous to the E. coli RelA protein. The a...

  16. The effect of carbon credits on savanna land management and priorities for biodiversity conservation.

    Science.gov (United States)

    Douglass, Lucinda L; Possingham, Hugh P; Carwardine, Josie; Klein, Carissa J; Roxburgh, Stephen H; Russell-Smith, Jeremy; Wilson, Kerrie A

    2011-01-01

    Carbon finance offers the potential to change land management and conservation planning priorities. We develop a novel approach to planning for improved land management to conserve biodiversity while utilizing potential revenue from carbon biosequestration. We apply our approach in northern Australia's tropical savanna, a region of global significance for biodiversity and carbon storage, both of which are threatened by current fire and grazing regimes. Our approach aims to identify priority locations for protecting species and vegetation communities by retaining existing vegetation and managing fire and grazing regimes at a minimum cost. We explore the impact of accounting for potential carbon revenue (using a carbon price of US$14 per tonne of carbon dioxide equivalent) on priority areas for conservation and the impact of explicitly protecting carbon stocks in addition to biodiversity. Our results show that improved management can potentially raise approximately US$5 per hectare per year in carbon revenue and prevent the release of 1-2 billion tonnes of carbon dioxide equivalent over approximately 90 years. This revenue could be used to reduce the costs of improved land management by three quarters or double the number of biodiversity targets achieved and meet carbon storage targets for the same cost. These results are based on generalised cost and carbon data; more comprehensive applications will rely on fine scale, site-specific data and a supportive policy environment. Our research illustrates that the duel objective of conserving biodiversity and reducing the release of greenhouse gases offers important opportunities for cost-effective land management investments.

  17. Synthesis of carbon-13 labelled carbonaceous deposits and their evaluation for potential use as surrogates to better understand the behaviour of the carbon-14-containing deposit present in irradiated PGA graphite

    OpenAIRE

    Payne, Liam; Walker, Susan J; Bond, Gary; Eccles, Harry; Heard, Peter J; Scott, Thomas Bligh; Williams, S.J.

    2016-01-01

    The present work has used microwave plasma chemical vapour deposition to generate suitable isotopically labelled carbonaceous deposits on the surface of Pile Grade A graphite for use as surrogates for studying the behaviour of the deposits observed on irradiated graphite extracted from UK Magnox reactors. These deposits have been shown elsewhere to contain an enhanced concentration of 14C compared to the bulk graphite. A combination of Raman spectroscopy, ion beam milling with scanning electr...

  18. Effect of aldicarb on growth and radio-carbon (14C) and radio-phosphorus (32P) assimilation by Rhizobium japonicum

    International Nuclear Information System (INIS)

    In vitro studies on the effect of aldicarb (2-methyl-2-(methyl thio) propionaldehde-o-methyl carbamoyl oxime), a soil applied systemic insecticide, on Rhizobium japonicum revealed that the chemical (at 1,2 and 5 ppm levels) stimulated the growth of the organism initially upto 48 hr which declined thereafter upto 72 hr. The incorporation of 14C-glucose by the cells considerably reduced due to the insecticide treatment. The production of extracellular, water-soluble slime (polysacchardes) was also reduced considerably with increased concentrations of the chemical. However, the incorporation of 14C-radio-activity in the extracellular slime generally enhanced due to the treatment, upto 6 hr after injection of the radioactivity, which declined significantly later at 15 hr, indicating a qualitative difference in the extracellular polysaccharides produced by the insecticide treated cells. The insecticide treatment drastically reduced the incorporation of 32P-disodium hydrogen phosphate into Rhizobium cells, but enhanced the specific activity of the extracellular polysacchrides. (author)

  19. Isotopic signatures (13C/12C; 15N/14N) of blue penguin burrow soil invertebrates : carbon sources and trophic relationships

    International Nuclear Information System (INIS)

    Seabird burrows provide a soil environment for processing discards such as feathers and guano, hence constituting a primary interface between the sea and the land. This study involved collection and culturing of soil invertebrates from three blue penguin (Eudyptula minor) burrows, and examined their 13C/12C and 15N/14N isotopic composition in relation to potential burrow resources (terrestrial plant litter, burrow soil, guano, blue penguin feathers). Two taxa (cerylonid beetles and small tineid moth larvae) had a depleted 13C/12C indicative of a level of dependence on C from terrestrial soil. Tineid moth larvae (Monopis crocicapitella and (or) M. ethelella) substantially increased their 13C/12C enrichment during development, implying increasing dependence on marine C. Remaining taxa, both decomposers and predators, had 13C/12C intermediate between guano and feathers. Larval and emergent fleas had the most enriched 13C/12C , indicative of a greater dependence on feather C and the likelihood of co-processing with guano. Pseudoscorpions and histerid beetles had overlapping isotopic enrichments implying competition for prey, but were spatially separated in burrow soil. With their highly enriched 15N/14N and marine 13C/12C, larvae and protonymphs of the histiostomatid mite Myianoetus antipodus stood alone. Blue penguin burrows therefore support a diverse invertebrate fauna that incorporates terrestrial soil as well as varying proportions of the various blue penguin discards. (author). 45 refs., 1 fig., 1 tab.

  20. 9,10-Dibromo-N-aryl-9,10-dihydro-9,10-[3,4]epipyrroloanthracene-12,14-diones: Synthesis and Investigation of Their Effects on Carbonic Anhydrase Isozymes I, II, IX, and XII.

    Science.gov (United States)

    Göksu, Haydar; Topal, Meryem; Keskin, Ali; Gültekin, Mehmet S; Çelik, Murat; Gülçin, İlhami; Tanc, Muhammet; Supuran, Claudiu T

    2016-06-01

    N-substituted maleimides were synthesized from maleic anhydride and primary amines. 1,4-Dibromo-dibenzo[e,h]bicyclo-[2,2,2]octane-2,3-dicarboximide derivatives (4a-f) were prepared by the [4+2] cycloaddition reaction of dibromoanthracenes with the N-substituted maleimide derivatives. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory effects of the new derivatives were assayed against the human (h) isozymes hCA I, II, IX, and XII. All tested bicyclo dicarboximide derivatives exhibited excellent inhibitory effects in the nanomolar range, with Ki values in the range of 117.73-232.87 nM against hCA I and of 69.74-111.51 nM against hCA II, whereas they were low micromolar inhibitors against hCA IX and XII. PMID:27174792

  1. Targeted management of organic resources for sustainably increasing soil organic carbon: Observations and perspectives for resource use and climate adaptations in northern Ghana

    DEFF Research Database (Denmark)

    Heve, William K; Olesen, Jørgen Eivind; Chirinda, Ngonidzashe;

    2016-01-01

    Since soil organic matter (SOM) buffers against impacts of climatic variability, the objective of this study was to assess on-farm distribution of SOM and propose realistic options for increasing SOM and thus the adaptation of smallholder farmers to climate change and variability in the interior...... northern savannah of Ghana. Data and information on spatial distribution of soil organic carbon (SOC), current practices that could enhance climate adaptation including management of organic resources were collected through biophysical assessments and snap community surveys. Even though homestead fields...

  2. A folic acid labelled carbon quantum dot-protoporphryin IX conjugate for use in folate receptor targeted two-photon excited photodynamic therapy

    Science.gov (United States)

    Nicholas, Dean; Fowley, Colin; McHale, Anthony P.; Kamila, Sukanta; Sheng, Jason; Atchison, Jordan; Callan, John F.

    2015-03-01

    Folic acid (FA) has been used as a molecular targeting strategy to improve the specificity of a CQD-protoporphyrin IX (CQD-PPIX) conjugate to folate receptor positive (FR+) HeLa cells for use in two-photon excited Photodynamic Therapy (TPE-PDT). FA was covalently attached to the CQD-PPIX conjugate to form a FA-CQD-PPIX conjugate. The uptake of the FA-CQD-PPIX conjugate in FR+ HeLa cells was shown to be 7 times greater than the CQD-PPIX conjugate, while both conjugates showed a similar uptake in FR negative (FR-) HT-47 cells. TPE-PDT experiments, using HeLa cells as a target, revealed a 30% improved cytotoxicity for cells treated with the FA-CQD-PPIX conjugate and TPE compared to controls treated with the CQD-PPIX conjugate and TPE. Collectively, these results suggest the presence of FA can facilitate targeting of CQD-sensitiser conjugates to FR+ cells resulting in an improved PDT effect.

  3. Production of an accelerated oxygen-14 beam

    CERN Document Server

    Powell, J; Cerny, J

    2003-01-01

    BEARS is an ongoing project to provide a light-ion radioactive-beam capability at the 88-Inch Cyclotron at LBNL. Light radioactive isotopes are produced at a 10 MeV proton medical cyclotron, transported 350 m via a high-speed gas transport capillary, cryogenically separated, and injected into the 88-Inch Cyclotron's ion source. The first radioactive beam successfully accelerated was carbon-11 and beams of intensity more than 10 sup 8 ions/s have been utilized for experiments. Development of oxygen-14 as the second BEARS beam presented considerable technical challenges, both due to its short half-life of 71 s and the radiation chemistry of oxygen in the target. The usual techniques developed for medical uses of oxygen-15 involve the addition of significant amounts of carrier oxygen, something that would overload the ion source. As a solution, oxygen-14 is produced as water in a carrier-free form, and is chemically converted in two steps to carbon dioxide, a form readily usable by the BEARS. This system has bee...

  4. Structure, stability, and nature of bonding in carbon monoxide bound EX3+ complexes (E = group 14 element; X = H, F, Cl, Br, I).

    Science.gov (United States)

    Ghara, Manas; Pan, Sudip; Kumar, Anand; Merino, Gabriel; Chattaraj, Pratim K

    2016-09-15

    A density functional theory study is performed to predict the structures and stability of carbon monoxide (CO) bound EX3+ (E = C, Si, Ge, Sn, Pb; X = H, F, Cl, Br, I) complexes. The possibility of bonding through both C- and O-sides of CO is considered. Thermochemical analysis reveals that all the dissociation processes producing CO and EX3+ are endothermic in nature whereas most of the dissociation reactions are endergonic in nature at room temperature. The nature of bonding in EC/O bonds is analyzed via Wiberg bond index, natural population analysis, electron density, and energy decomposition analyses in conjunction with natural orbitals for chemical valence scheme. In comparison to CO stretching frequency ( ν∼CO) in free CO, while a red shift is noted in O-side binding, the C-side binding results in a blue shift in ν∼CO. The relative change in ν∼CO values in CO bound EX3+ complexes on changing either E or X is scrutinized and possible explanation is provided in terms of polarization in the σ- and π-orbitals and the relative strength of C→E or O→E σ-donation and E→C or E→O π-back-donation. © 2016 Wiley Periodicals, Inc. PMID:27425405

  5. Primary production off Southern California relative to surface layer carbon budgets: A component of the California Basins Study, CaBS. Final report, [1 June 1989--14 November 1991

    Energy Technology Data Exchange (ETDEWEB)

    Trees, C.C.

    1994-04-22

    This study started on 1 June 1989 and ended 14 November 1991. Two moored in situ natural fluorometers were deployed in January 1990 to collect bio-optical data for one year, making ground truth measurements around the mooring during 4 cruises. This one-year time series would investigate how the short-term physical forcing aliases the long-term primary production record such that the apparent, larger interannual variability in the record is in reality ``noise`` due to short-term fluctuations in the rate of nutrient input to the euphotic zone. These continuous measurements from moored bio-optical instruments would also allow better estimates of the mean and variance in primary production in these waters than has previously been available from shipboard measurements, as well as, phytoplankton response to short-term physical events. Ancillary measurements that were made were: (1) characterization of the apparent and inherent optical properties, (2) photosynthetic pigment distributions using both HPLC and standard fluorometric methods, (3) carbon, hydrogen and nitrogen content of suspended particulate matter, (4) primary production using conventional {sup 14}C methods from simulated in situ experiments.

  6. β-alumina-14H and β-alumina-21R: Two chromic Na2-δ(Al,Mg,Cr)17O25 polysomes observed in slags from the production of low-carbon ferrochromium

    Science.gov (United States)

    Hejny, Clivia; Kahlenberg, Volker; Schmidmair, Daniela; Tribus, Martina; deVilliers, Johan

    2016-09-01

    The crystal structures of unknown phases found in slags from the production of low-carbon ferrochromium were studied by powder and single-crystal X-ray diffraction. Two phases of Na2-δ(Al, Mg, Cr)17O25 composition were found to be composed of an alternating stacking of a spinel-type and a Na-hosting block. Similar structures are known for β-alumina and β"-alumina, NaAl11O17. However, the spinel-type block in Na2-δ(Al, Mg, Cr)17O25 is composed of five cation layers in contrast to three cation layers in the β-alumina spinel-block. The two new phases, β-alumina-14H, P63/mmc, a=5.6467(2), c=31.9111(12) Å, and β-alumina-21R, R 3 ̅m, a=5.6515(3), c=48.068(3) Å have a 14-layer and 21-layer stacking with a 2 × (cccccch) and a 3 × (ccccccc) repeat sequence of oxygen layers in cubic and hexagonal close packing, respectively.

  7. CERN: Fixed target targets

    International Nuclear Information System (INIS)

    Full text: While the immediate priority of CERN's research programme is to exploit to the full the world's largest accelerator, the LEP electron-positron collider and its concomitant LEP200 energy upgrade (January, page 1), CERN is also mindful of its long tradition of diversified research. Away from LEP and preparations for the LHC proton-proton collider to be built above LEP in the same 27-kilometre tunnel, CERN is also preparing for a new generation of heavy ion experiments using a new source, providing heavier ions (April 1992, page 8), with first physics expected next year. CERN's smallest accelerator, the LEAR Low Energy Antiproton Ring continues to cover a wide range of research topics, and saw a record number of hours of operation in 1992. The new ISOLDE on-line isotope separator was inaugurated last year (July, page 5) and physics is already underway. The remaining effort concentrates around fixed target experiments at the SPS synchrotron, which formed the main thrust of CERN's research during the late 1970s. With the SPS and LEAR now approaching middle age, their research future was extensively studied last year. Broadly, a vigorous SPS programme looks assured until at least the end of 1995. Decisions for the longer term future of the West Experimental Area of the SPS will have to take into account the heavy demand for test beams from work towards experiments at big colliders, both at CERN and elsewhere. The North Experimental Area is the scene of larger experiments with longer lead times. Several more years of LEAR exploitation are already in the pipeline, but for the longer term, the ambitious Superlear project for a superconducting ring (January 1992, page 7) did not catch on. Neutrino physics has a long tradition at CERN, and this continues with the preparations for two major projects, the Chorus and Nomad experiments (November 1991, page 7), to start next year in the West Area. Delicate neutrino oscillation effects could become

  8. Formation of short-lived positron emitters in reactions of protons of energies up to 200 MeV with the target elements carbon, nitrogen and oxygen

    CERN Document Server

    Kettern, K; Qaim, S M; Shubin, Yu N; Steyn, G F; Van der Walt, T N; 10.1016/j.apradiso.2004.02.007

    2004-01-01

    Excitation functions were measured by the stacked-foil technique for proton induced reactions on carbon, nitrogen and oxygen leading to the formation of the short-lived positron emitters /sup 11/C (T/sub 1 /2/=20.38 min) and /sup 13/N (T/sub 1/2/=9.96 min). The energy region covered extended up to 200 MeV. The product activity was measured non-destructively via gamma -ray spectrometry. A careful decay curve analysis of the positron annihilation radiation was invariably performed. The experimental results were compared with theoretical data obtained using the modified hybrid nuclear model code ALICE-IPPE for intermediate energies. The agreement was found to be generally satisfactory. The data are of importance in proton therapy.

  9. Genesis Silicon Carbide Concentrator Target 60003 Preliminary Ellipsometry Mapping Results

    Science.gov (United States)

    Calaway, M. J.; Rodriquez, M. C.; Stansbery, E. K.

    2007-01-01

    The Genesis concentrator was custom designed to focus solar wind ions primarily for terrestrial isotopic analysis of O-17/O-16 and O-18/O-16 to +/-1%, N-15/N-14 to +/-1%, and secondarily to conduct elemental and isotopic analysis of Li, Be, and B. The circular 6.2 cm diameter concentrator target holder was comprised of four quadrants of highly pure semiconductor materials that included one amorphous diamond-like carbon, one C-13 diamond, and two silicon carbide (SiC). The amorphous diamond-like carbon quadrant was fractured upon impact at Utah Test and Training Range (UTTR), but the remaining three quadrants survived fully intact and all four quadrants hold an important collection of solar wind. The quadrants were removed from the target holder at NASA Johnso n Space Center Genesis Curation Laboratory in April 2005, and have been housed in stainless steel containers under continual nitrogen purge since time of disintegration. In preparation for allocation of a silicon carbide target for oxygen isotope analyses at UCLA, the two SiC targets were photographed for preliminary inspection of macro particle contamination from the hard non-nominal landing as well as characterized by spectroscopic ellipsometry to evaluate thin film contamination. This report is focused on Genesis SiC target sample number 60003.

  10. Smelting Process Research of Ultra-low Carbon Duplex Stainless Steel of 00Cr14Ni5Mo3Al%超低碳双相不锈钢00Cr14Ni5Mo3Al冶炼工艺研究

    Institute of Scientific and Technical Information of China (English)

    赵杰; 郭淑娟; 张秀丽

    2012-01-01

    00Crl4Ni5Mo3Al is a new ultra low carbon martensite-ferrite dual phase stainless steel, it can fit well to our country color film? Film career development and application of extrusion coating technology and new materials. In this paper,combining with the high production costs status of ultra low carbon dual-phase stainless steel 00Crl4Ni5Mo3Al in Fush-un steel group, adopting the appropriate measures, the new smelting crafts was made successfully from the vacuum induction furnace -h ESR technology to electric furnace +VOD-H ESR smelting, the forging process was improved too. Results indicated that the new process was reasonable and practicable, it can not only ensure the chemical composition of the steel and good quality, but also can greatly reduce the costs of production.%00Cr14Ni5Mo3Al是一种新型的超低碳马氏体一铁素体双相不锈钢,是应我国彩色电影、胶片事业的发展而得到应用的挤压涂布工艺新材料.结合抚钢生产的超低碳双相不锈钢00Cr14Ni5Mo3Al成本较高的现状,通过制订相应的生产工艺措施,成功将真空感应炉+电渣工艺改为电炉+ VOD+电渣工艺冶炼,并进行锻造工艺改进.结果表明,新工艺合理可行,既保证了钢的化学成分及良好的内部质量,同时又大大地降低了生产成本.

  11. Sputter target

    Science.gov (United States)

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

  12. Role of Hypoxia-inducible factor-1 and its target genes in human lung adenocarcinoma cells after photon- versus carbon ion irradiation

    International Nuclear Information System (INIS)

    Exposed to hypoxia tumor cells are notably resistant to photon irradiation. The hypoxiainducible transcription factor 1α (HIF-1α) seems to play a fundamental role in this resistance, while its role after heavy-ion beam remains unknown. The intention of this study was to determine how A549-cells (non-small-cell lung carcinoma) react in different oxygenation states after irradiation with photons or heavy ions, particularly in regards to their expression of HIF-1 target genes. Resistance of hypoxic A549 cells after photon irradiation was documented by cellular and clonogenic survival. In contrast, cellular survival after heavy-ion irradiation in hypoxic cells was not elevated to normoxic cells. Among the oxygen dependent regulation of HIF-1 target genes, gene expression analyses showed an increased expression of GLUT-1, LDH-A, PDK-1 and VEGF after photon irradiation but not after heavy-ion irradiation after 48 hours in normoxic cells. As expected, CDKN1A as inhibitor of cell cycle progression showed higher expression after both radiation forms; interestingly CDKN1A was also in an oxygen dependent manner lightly upregulated. In western blot analyses we demonstrated a significant increase of HIF-1 and GLUT-1 caused by hypoxia, but only a tendency of increased protein level in hypoxia after photon irradiation and no changes after heavy-ion irradiation. Significantly higher protein level of secreted VEGF-A could be measured 72 hours after photon irradiation in normoxic cells by ELISA analyses. Controversially discussed, I could not detect an association between HIF-1 and SCF or Trx-1 in A549-cells in this study. Whereas Trx-1-expression was neither influenced by changed oxygen partial pressure nor irradiation, I could show increased SCF mRNA by quantitative Real Time-PCR and secreted protein level by ELISA after photon irradiation independent of oxygen state. In summary, this study showed that HIF-1 and its target genes (GLUT-1, LDHA; PDK, VEGF) and also SCF was

  13. HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES

    Energy Technology Data Exchange (ETDEWEB)

    David E. Eby; Thomas C. Chidsey, Jr.; Kevin McClure; Craig D. Morgan

    2003-07-01

    The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m{sup 3}) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m{sup 3}) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing vertical wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the second half of the third project year (October 6, 2002, through April 5, 2003). The primary work included describing and mapping regional facies of the upper Ismay and lower Desert Creek zones of the Paradox Formation in the Blanding sub-basin, Utah. Regional cross sections show the development of ''clean carbonate'' packages that contain all of the productive reservoir facies. These clean carbonates abruptly change laterally into thick anhydrite packages that filled several small intra-shelf basins in the upper Ismay zone

  14. The risk of leukaemia in young children from exposure to tritium and carbon-14 in the discharges of German nuclear power stations and in the fallout from atmospheric nuclear weapons testing.

    Science.gov (United States)

    Wakeford, Richard

    2014-05-01

    Towards the end of 2007, the results were published from a case-control study (the "KiKK Study") of cancer in young children, diagnosed nuclear power stations in western Germany. The study found a tendency for cases of leukaemia to live closer to the nearest nuclear power station than their matched controls, producing an odds ratio that was raised to a statistically significant extent for residence within 5 km of a nuclear power station. The findings of the study received much publicity, but a detailed radiological risk assessment demonstrated that the radiation doses received by young children from discharges of radioactive material from the nuclear reactors were much lower than those received from natural background radiation and far too small to be responsible for the statistical association reported in the KiKK Study. This has led to speculation that conventional radiological risk assessments have grossly underestimated the risk of leukaemia in young children posed by exposure to man-made radionuclides, and particular attention has been drawn to the possible role of tritium and carbon-14 discharges in this supposedly severe underestimation of risk. Both (3)H and (14)C are generated naturally in the upper atmosphere, and substantial increases in these radionuclides in the environment occurred as a result of their production by atmospheric testing of nuclear weapons during the late 1950s and early 1960s. If the leukaemogenic effect of these radionuclides has been seriously underestimated to the degree necessary to explain the KiKK Study findings, then a pronounced increase in the worldwide incidence of leukaemia among young children should have followed the notably elevated exposure to (3)H and (14)C from nuclear weapons testing fallout. To investigate this hypothesis, the time series of incidence rates of leukaemia among young children nuclear weapons testing, or that incidence rates are related to level of exposure to fallout, is apparent from these

  15. Determining novel functions of Arabidopsis 14-3-3 proteins in central metabolic processes

    Directory of Open Access Journals (Sweden)

    Diaz Celine

    2011-11-01

    Full Text Available Abstract Background 14-3-3 proteins are considered master regulators of many signal transduction cascades in eukaryotes. In plants, 14-3-3 proteins have major roles as regulators of nitrogen and carbon metabolism, conclusions based on the studies of a few specific 14-3-3 targets. Results In this study, extensive novel roles of 14-3-3 proteins in plant metabolism were determined through combining the parallel analyses of metabolites and enzyme activities in 14-3-3 overexpression and knockout plants with studies of protein-protein interactions. Decreases in the levels of sugars and nitrogen-containing-compounds and in the activities of known 14-3-3-interacting-enzymes were observed in 14-3-3 overexpression plants. Plants overexpressing 14-3-3 proteins also contained decreased levels of malate and citrate, which are intermediate compounds of the tricarboxylic acid (TCA cycle. These modifications were related to the reduced activities of isocitrate dehydrogenase and malate dehydrogenase, which are key enzymes of TCA cycle. In addition, we demonstrated that 14-3-3 proteins interacted with one isocitrate dehydrogenase and two malate dehydrogenases. There were also changes in the levels of aromatic compounds and the activities of shikimate dehydrogenase, which participates in the biosynthesis of aromatic compounds. Conclusion Taken together, our findings indicate that 14-3-3 proteins play roles as crucial tuners of multiple primary metabolic processes including TCA cycle and the shikimate pathway.

  16. Impact of suppression of tumorigenicity 14 (ST14)/serine protease 14 (Prss14) expression analysis on the prognosis and management of estrogen receptor negative breast cancer.

    Science.gov (United States)

    Kim, Sauryang; Yang, Jae Woong; Kim, Chungho; Kim, Moon Gyo

    2016-06-01

    To elucidate the role of a type II transmembrane serine protease, ST14/Prss14, during breast cancer progression, we utilized publically accessible databases including TCGA, GEO, NCI-60, and CCLE. Survival of breast cancer patients with high ST14/Prss14 expression is significantly poor in estrogen receptor (ER) negative populations regardless of the ratios of ST14/Prss14 to its inhibitors, SPINT1 or SPINT2. In a clustering of 1085 selected EMT signature genes, ST14/Prss14 is located in the same cluster with CDH3, and closer to post-EMT markers, CDH2, VIM, and FN1 than to the pre-EMT marker, CDH1. Coexpression analyses of known ST14/Prss14 substrates and transcription factors revealed context dependent action. In cell lines, paradoxically, ST14/Prss14 expression is higher in the ER positive group and located closer to CDH1 in clustering. This apparent contradiction is not likely due to ST14/Prss14 expression in a cancer microenvironment, nor due to negative regulation by ER. Genes consistently coexpressed with ST14/Prss14 include transcription factors, ELF5, GRHL1, VGLL1, suggesting currently unknown mechanisms for regulation. Here, we report that ST14/Prss14 is an emerging therapeutic target for breast cancer where HER2 is not applicable. In addition we suggest that careful conclusions should be drawn not exclusively from the cell line studies for target development.

  17. The use of 14C ethanolamine as a precursor

    International Nuclear Information System (INIS)

    Two new 2 chloroethyl nitrosoureas were labelled on two positions by 14C starting from Na14CN and using 14C ethanolamine as intermediate, i.e. on the carbon 2 of the 2 chloro ethyl group and on the carbon 2 of the cysteamine part. (author)

  18. Thermophilic Anaerobic Biodegradation of [14C]Lignin, [14C]Cellulose, and [14C]Lignocellulose Preparations

    OpenAIRE

    Benner, Ronald; Hodson, Robert E.

    1985-01-01

    Thermophilic (55°C) anaerobic enrichment cultures were incubated with [14C-lignin]lignocellulose, [14C-polysaccharide]lignocellulose, and kraft [14C]lignin prepared from slash pine, Pinus elliottii, and 14C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were ...

  19. SATS 14

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth; Andreasen, Lars Birch; Hansen, Susanne Pihl

    SATS14 projektet har drejet sig om at undersøge mulighederne i at kunne tilbyde en særlig indsats til de produktionsskoleelever, der har brug for det, så vidt muligt lokalt på deres skole. Projektets formål har været at indhente erfaringer med at tilbyde elever på 14 produktionsskoler på Sjælland...... mål. SATS14 kan dermed ses i en større social sammenhæng. Der er en stigende erkendelse af behovet for initiativer til at hjælpe de elever, der oplever psykiske vanskeligheder. I forordet til en rapport fra Undervisningsministeriet om erhvervsuddannelser beskrives målet: ”95 procent af en...... ungdomsårgang i 2015 skal gennemføre en ungdomsuddannelse… For at opfylde regeringens mål… er det nødvendigt med en særlig indsats for at fastholde de unge, som begynder i en uddannelse, herunder også de bogligt svage” (Kirkegaard og Nielsen, 2008). Da SATS14 projektet startede, var der ikke megen opmærksomhed...

  20. Metal incorporation into nanoporous carbon

    OpenAIRE

    Henley, SJ; Woolger, NEP; Carey, JD; Silva, SRP; Fuge, GM; Ashfold, MNR

    2005-01-01

    Nanoporous carbon films were deposited by 248 nm pulsed laser ablation of a graphite target in different background pressures of argon (P). The morphology changed from smooth, high-density amorphous carbon films at P = 20 mTorr to ultra-low density nanoporous material at P = 380 mTorr. Subsequently, the nanostructural, chemical and electrical properties of metal containing nanoporous carbon samples were investigated by ablating graphite targets containing known contents of Ni and Co. We demon...

  1. Indirectly driven targets for inertial confinement fusion

    International Nuclear Information System (INIS)

    The physics of indirectly driven targets for inertial confinement fusion - so called hohlraum targets - is investigated. Scaling relations for radiation heat waves in high-Z and low-Z materials are derived from one-dimensional multigroup simulation. A two-temperature model is developed for radiation cavities including fusion capsules. The efficiency of X-ray transfer to the capsule by multiple absorption and re-emission inside the cavity is obtained as a function of cavity areas and materials. Using gold for the cavity wall and carbon for the capsule ablator, transfer efficiencies between 50% and 33% are obtained for area ratios between 5 and 10, respectively. Also, the hydrodynamic efficiency of X-ray driven capsule implosion and the dependence of the implosion velocity on the hohlraum temperature are given analytically, derived from the rocket model. With carbon ablators, hydroefficiencies of up to 20% can be achieved. Under optimal conditions, an implosion velocity of 3 x 107 cm/s is reached with a temperature of about 210 eV of the capsule ablator and about 250 eV of the cavity wall. Assuming 70-90% conversion efficiency of beam energy into X-rays (not analysed in this paper), overall coupling efficiencies in the range of 5-10% seem to be possible. One-dimensional simulations of full reactor size targets (10MJ driver pulses) are presented. The model results compare well with the simulations. Limit in scaling down to smaller systems are discussed; the scaling relation for the required enhancement of implosion velocity and hohlraum temperature is derived. (author). 21 refs, 14 figs, 1 tab

  2. Antiproton Target

    CERN Multimedia

    1980-01-01

    Antiproton target used for the AA (antiproton accumulator). The first type of antiproton production target used from 1980 to 1982 comprised a rod of copper 3mm diameter and 120mm long embedded in a graphite cylinder that was itself pressed into a finned aluminium container. This assembly was air-cooled and it was used in conjunction with the Van der Meer magnetic horn. In 1983 Fermilab provided us with lithium lenses to replace the horn with a view to increasing the antiproton yield by about 30%. These lenses needed a much shorter target made of heavy metal - iridium was chosen for this purpose. The 50 mm iridium rod was housed in an extension to the original finned target container so that it could be brought very close to the entrance to the lithium lens. Picture 1 shows this target assembly and Picture 2 shows it mounted together with the lithium lens. These target containers had a short lifetime due to a combination of beam heating and radiation damage. This led to the design of the water-cooled target in...

  3. Etude de la migration des interstitiels dans des austenites Fe, Cr (18), Ni (14) pures et industrielles par irradiation dans un microscope a tres haute tension: Role du carbone et du titane

    Science.gov (United States)

    Housseau, N.; Pelissier, J.

    1983-12-01

    Nous avons étudié le rôle des impurtés (C ou Ti) dans la condensation et la migration des défauts interstitiels. Les échantillons étudiés sont des aciers austénitiques: (a) acier de synthèse de haute pureté (Cr 18, Ni 14, Fe) avec ou sans carbone; (b) acier industriel avec C (800 ppm) ou Ti (0,45%). Les échantillons ont été irradiés dans un microscope à très haute tension aux doses allant de 10 -4 jusqu'à 10 -1 dpa aux températures de 300°C à 400°C. Dans de telles conditions les défauts observés sont des boucles interstitielles. L'étude de la variation de l'épaisseur de la zone dénudée près du bord de la lame mince en fonction de la température nous a permis d'évaluer l'énergie de migration effective de l'interstitiel dans ces alliages. Dans l'austénite de synthèse carburée ou non sa valeur est de 0.8 eV. Dans l'acier industriel au titane carburé ou non on obtient 2.0 eV. Nous n'avons pas observé d'effet lié au carbone. L'examen de la densité de boucles à saturation dans les divers aciers suggère une forte énergie de liaison interstitiel-titane. Cette énergie de liaison, si l'ont admet que le titane est la seule impureté agissante du système, peut être estimée à 1.2 eV.

  4. Functionalization of Carbon Nanotubes

    Science.gov (United States)

    Khare, Bishun N. (Inventor); Meyyappan, Meyya (Inventor)

    2009-01-01

    Method and system for functionalizing a collection of carbon nanotubes (CNTs). A selected precursor gas (e.g., H2 or F2 or CnHm) is irradiated to provide a cold plasma of selected target species particles, such as atomic H or F, in a first chamber. The target species particles are d irected toward an array of CNTs located in a second chamber while suppressing transport of ultraviolet radiation to the second chamber. A CNT array is functionalized with the target species particles, at or below room temperature, to a point of saturation, in an exposure time interval no longer than about 30 sec. *Discrimination against non-target species is provided by (i) use of a target species having a lifetime that is much greater than a lifetime of a non-target species and/or (2) use of an applied magnetic field to discriminate between charged particle trajectories for target species and for non-target species.

  5. Epigenetic upregulation of lncRNAs at 13q14.3 in leukemia is linked to the In Cis downregulation of a gene cluster that targets NF-kB.

    Directory of Open Access Journals (Sweden)

    Angela Garding

    2013-04-01

    Full Text Available Non-coding RNAs are much more common than previously thought. However, for the vast majority of non-coding RNAs, the cellular function remains enigmatic. The two long non-coding RNA (lncRNA genes DLEU1 and DLEU2 map to a critical region at chromosomal band 13q14.3 that is recurrently deleted in solid tumors and hematopoietic malignancies like chronic lymphocytic leukemia (CLL. While no point mutations have been found in the protein coding candidate genes at 13q14.3, they are deregulated in malignant cells, suggesting an epigenetic tumor suppressor mechanism. We therefore characterized the epigenetic makeup of 13q14.3 in CLL cells and found histone modifications by chromatin-immunoprecipitation (ChIP that are associated with activated transcription and significant DNA-demethylation at the transcriptional start sites of DLEU1 and DLEU2 using 5 different semi-quantitative and quantitative methods (aPRIMES, BioCOBRA, MCIp, MassARRAY, and bisulfite sequencing. These epigenetic aberrations were correlated with transcriptional deregulation of the neighboring candidate tumor suppressor genes, suggesting a coregulation in cis of this gene cluster. We found that the 13q14.3 genes in addition to their previously known functions regulate NF-kB activity, which we could show after overexpression, siRNA-mediated knockdown, and dominant-negative mutant genes by using Western blots with previously undescribed antibodies, by a customized ELISA as well as by reporter assays. In addition, we performed an unbiased screen of 810 human miRNAs and identified the miR-15/16 family of genes at 13q14.3 as the strongest inducers of NF-kB activity. In summary, the tumor suppressor mechanism at 13q14.3 is a cluster of genes controlled by two lncRNA genes that are regulated by DNA-methylation and histone modifications and whose members all regulate NF-kB. Therefore, the tumor suppressor mechanism in 13q14.3 underlines the role both of epigenetic aberrations and of lncRNA genes

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from time series observations using Bubble type equilibrator for autonomous carbon dioxide (CO2) measurement, Carbon dioxide (CO2) gas analyzer and other instruments from the MOORINGS in the North Pacific Ocean from 1997-11-14 to 2010-08-25 (NODC Accession 0100084)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0100084 includes chemical, physical, and time series data collected from MOORINGS in the North Pacific Ocean from 1997-11-14 to 2010-08-25. These...

  7. Accounting for biomass carbon stock change due to wildfire in temperate forest landscapes in Australia.

    Directory of Open Access Journals (Sweden)

    Heather Keith

    Full Text Available Carbon stock change due to forest management and disturbance must be accounted for in UNFCCC national inventory reports and for signatories to the Kyoto Protocol. Impacts of disturbance on greenhouse gas (GHG inventories are important for many countries with large forest estates prone to wildfires. Our objective was to measure changes in carbon stocks due to short-term combustion and to simulate longer-term carbon stock dynamics resulting from redistribution among biomass components following wildfire. We studied the impacts of a wildfire in 2009 that burnt temperate forest of tall, wet eucalypts in south-eastern Australia. Biomass combusted ranged from 40 to 58 tC ha(-1, which represented 6-7% and 9-14% in low- and high-severity fire, respectively, of the pre-fire total biomass carbon stock. Pre-fire total stock ranged from 400 to 1040 tC ha(-1 depending on forest age and disturbance history. An estimated 3.9 TgC was emitted from the 2009 fire within the forest region, representing 8.5% of total biomass carbon stock across the landscape. Carbon losses from combustion were large over hours to days during the wildfire, but from an ecosystem dynamics perspective, the proportion of total carbon stock combusted was relatively small. Furthermore, more than half the stock losses from combustion were derived from biomass components with short lifetimes. Most biomass remained on-site, although redistributed from living to dead components. Decomposition of these components and new regeneration constituted the greatest changes in carbon stocks over ensuing decades. A critical issue for carbon accounting policy arises because the timeframes of ecological processes of carbon stock change are longer than the periods for reporting GHG inventories for national emissions reductions targets. Carbon accounts should be comprehensive of all stock changes, but reporting against targets should be based on human-induced changes in carbon stocks to incentivise

  8. Accounting for biomass carbon stock change due to wildfire in temperate forest landscapes in Australia.

    Science.gov (United States)

    Keith, Heather; Lindenmayer, David B; Mackey, Brendan G; Blair, David; Carter, Lauren; McBurney, Lachlan; Okada, Sachiko; Konishi-Nagano, Tomoko

    2014-01-01

    Carbon stock change due to forest management and disturbance must be accounted for in UNFCCC national inventory reports and for signatories to the Kyoto Protocol. Impacts of disturbance on greenhouse gas (GHG) inventories are important for many countries with large forest estates prone to wildfires. Our objective was to measure changes in carbon stocks due to short-term combustion and to simulate longer-term carbon stock dynamics resulting from redistribution among biomass components following wildfire. We studied the impacts of a wildfire in 2009 that burnt temperate forest of tall, wet eucalypts in south-eastern Australia. Biomass combusted ranged from 40 to 58 tC ha(-1), which represented 6-7% and 9-14% in low- and high-severity fire, respectively, of the pre-fire total biomass carbon stock. Pre-fire total stock ranged from 400 to 1040 tC ha(-1) depending on forest age and disturbance history. An estimated 3.9 TgC was emitted from the 2009 fire within the forest region, representing 8.5% of total biomass carbon stock across the landscape. Carbon losses from combustion were large over hours to days during the wildfire, but from an ecosystem dynamics perspective, the proportion of total carbon stock combusted was relatively small. Furthermore, more than half the stock losses from combustion were derived from biomass components with short lifetimes. Most biomass remained on-site, although redistributed from living to dead components. Decomposition of these components and new regeneration constituted the greatest changes in carbon stocks over ensuing decades. A critical issue for carbon accounting policy arises because the timeframes of ecological processes of carbon stock change are longer than the periods for reporting GHG inventories for national emissions reductions targets. Carbon accounts should be comprehensive of all stock changes, but reporting against targets should be based on human-induced changes in carbon stocks to incentivise mitigation activities

  9. Carbon Carbon Composites: An Overview .

    OpenAIRE

    G. Rohini Devi; K. Rama Rao

    1993-01-01

    Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several indust...

  10. Study of secondary electron emission from thin carbon targets with swift charged particles: heavy ions, hydrogen ions; Etude experimentale de l`emission electronique secondaire de cibles minces de carbone sous l`impact de projectiles rapides: ions lourds, ions hydrogene (atomiques, moleculaires ou sous forme d`agregats)

    Energy Technology Data Exchange (ETDEWEB)

    Billebaud, A.

    1995-07-12

    The main subject of this work is the study of electron emission from the two surfaces of thin solid targets bombarded with swift charged particles. The slowing down of swift ions in matter is mainly due to inelastic interaction with target electrons (ionization, excitation): the energy transfer to target electrons is responsible for the secondary electron emission process. The phenomenological and theoretical descriptions of this phenomena are the subject of the first chapter. We focused on secondary electron emission induced by different kind of projectiles on thin carbon foils. In chapter two we describe hydrogen cluster induced electron emission measurement between 40 and 120 keV/proton. These projectiles, composed of several atoms, allowed us to study and highlight collective effects of the electron emission process. We extended our study of electron emission to molecular (H{sub 2}{sup +}, H{sub 3}{sup +}) and composite (H{sup -}, H{sup 0}) projectiles at higher energies (<= 2 MeV): we have designed an experimental set-up devoted to electron emission statistics measurements which allowed us to study, among others things, the role of projectile electrons in secondary electron emission. This experiment is described in the third chapter. Finally, the fourth chapter describes new measurements of electron emission induced by energetic (13 MeV/u) and highly charged argon ion provided by the medium energy beam line (SME) of GANIL (Caen), which have been analyzed in the framework of a semi-empirical model of secondary electron emission. This set of experiments brings new results on composite projectile interaction with matter, and on the consequences of high energy deposition in solids. (author).

  11. Targeted Learning

    CERN Document Server

    van der Laan, Mark J

    2011-01-01

    The statistics profession is at a unique point in history. The need for valid statistical tools is greater than ever; data sets are massive, often measuring hundreds of thousands of measurements for a single subject. The field is ready to move towards clear objective benchmarks under which tools can be evaluated. Targeted learning allows (1) the full generalization and utilization of cross-validation as an estimator selection tool so that the subjective choices made by humans are now made by the machine, and (2) targeting the fitting of the probability distribution of the data toward the targe

  12. In-phantom dosimetry using the 13C(d,n)14N reaction for BNCT (boron neutron capture therapy)

    International Nuclear Information System (INIS)

    The use of the 13 C(d,n)14 N reaction at Ed =1.5 MeV for accelerator-based boron neutron capture therapy is investigated. The 13 C(d,n)14 N reaction presents the advantages of carbon as a target material and its large cross section. The deuteron beam was produced by a tandem accelerator at MIT's Laboratory for Accelerator Beam Applications. The resulting neutron spectra were evaluated in terms of RBE-dose rates at different depths inside a water-filled brain phantom using a heavy water moderator and lead reflector assembly. All results were simulated using the code MCNP. (author)

  13. Carbon Carbon Composites: An Overview .

    Directory of Open Access Journals (Sweden)

    G. Rohini Devi

    1993-10-01

    Full Text Available Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several industrial and biomedical applications. The multidirectional carbon-carbon product technology is versatile and offers design flexibility. This paper describes the multidirectional preform and carbon-carbon process technology and research and development activities within the country. Carbon-carbon product experience at DRDL has also been discussed. Development of carbon-carbon brake discs process technology using the liquid impregnation process is described. Further the test results on material characterisation, thermal, mechanical and tribological properties are presented.

  14. Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates

    Science.gov (United States)

    Petrenko, Vasilii V.; Severinghaus, Jeffrey P.; Schaefer, Hinrich; Smith, Andrew M.; Kuhl, Tanner; Baggenstos, Daniel; Hua, Quan; Brook, Edward J.; Rose, Paul; Kulin, Robb; Bauska, Thomas; Harth, Christina; Buizert, Christo; Orsi, Anais; Emanuele, Guy; Lee, James E.; Brailsford, Gordon; Keeling, Ralph; Weiss, Ray F.

    2016-03-01

    Carbon-14 (14C) is incorporated into glacial ice by trapping of atmospheric gases as well as direct near-surface in situ cosmogenic production. 14C of trapped methane (14CH4) is a powerful tracer for past CH4 emissions from "old" carbon sources such as permafrost and marine CH4 clathrates. 14C in trapped carbon dioxide (14CO2) can be used for absolute dating of ice cores. In situ produced cosmogenic 14C in carbon monoxide (14CO) can potentially be used to reconstruct the past cosmic ray flux and past solar activity. Unfortunately, the trapped atmospheric and in situ cosmogenic components of 14C in glacial ice are difficult to disentangle and a thorough understanding of the in situ cosmogenic component is needed in order to extract useful information from ice core 14C. We analyzed very large (≈1000 kg) ice samples in the 2.26-19.53 m depth range from the ablation zone of Taylor Glacier, Antarctica, to study in situ cosmogenic production of 14CH4 and 14CO. All sampled ice is >50 ka in age, allowing for the assumption that most of the measured 14C originates from recent in situ cosmogenic production as ancient ice is brought to the surface via ablation. Our results place the first constraints on cosmogenic 14CH4 production rates and improve on prior estimates of 14CO production rates in ice. We find a constant 14CH4/14CO production ratio (0.0076 ± 0.0003) for samples deeper than 3 m, which allows the use of 14CO for correcting the 14CH4 signals for the in situ cosmogenic component. Our results also provide the first unambiguous confirmation of 14C production by fast muons in a natural setting (ice or rock) and suggest that the 14C production rates in ice commonly used in the literature may be too high.

  15. 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.

  16. 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

  17. The effect of carbon credits on savanna land management and priorities for biodiversity conservation.

    Science.gov (United States)

    Douglass, Lucinda L; Possingham, Hugh P; Carwardine, Josie; Klein, Carissa J; Roxburgh, Stephen H; Russell-Smith, Jeremy; Wilson, Kerrie A

    2011-01-01

    Carbon finance offers the potential to change land management and conservation planning priorities. We develop a novel approach to planning for improved land management to conserve biodiversity while utilizing potential revenue from carbon biosequestration. We apply our approach in northern Australia's tropical savanna, a region of global significance for biodiversity and carbon storage, both of which are threatened by current fire and grazing regimes. Our approach aims to identify priority locations for protecting species and vegetation communities by retaining existing vegetation and managing fire and grazing regimes at a minimum cost. We explore the impact of accounting for potential carbon revenue (using a carbon price of US$14 per tonne of carbon dioxide equivalent) on priority areas for conservation and the impact of explicitly protecting carbon stocks in addition to biodiversity. Our results show that improved management can potentially raise approximately US$5 per hectare per year in carbon revenue and prevent the release of 1-2 billion tonnes of carbon dioxide equivalent over approximately 90 years. This revenue could be used to reduce the costs of improved land management by three quarters or double the number of biodiversity targets achieved and meet carbon storage targets for the same cost. These results are based on generalised cost and carbon data; more comprehensive applications will rely on fine scale, site-specific data and a supportive policy environment. Our research illustrates that the duel objective of conserving biodiversity and reducing the release of greenhouse gases offers important opportunities for cost-effective land management investments. PMID:21935363

  18. The effect of carbon credits on savanna land management and priorities for biodiversity conservation.

    Directory of Open Access Journals (Sweden)

    Lucinda L Douglass

    Full Text Available Carbon finance offers the potential to change land management and conservation planning priorities. We develop a novel approach to planning for improved land management to conserve biodiversity while utilizing potential revenue from carbon biosequestration. We apply our approach in northern Australia's tropical savanna, a region of global significance for biodiversity and carbon storage, both of which are threatened by current fire and grazing regimes. Our approach aims to identify priority locations for protecting species and vegetation communities by retaining existing vegetation and managing fire and grazing regimes at a minimum cost. We explore the impact of accounting for potential carbon revenue (using a carbon price of US$14 per tonne of carbon dioxide equivalent on priority areas for conservation and the impact of explicitly protecting carbon stocks in addition to biodiversity. Our results show that improved management can potentially raise approximately US$5 per hectare per year in carbon revenue and prevent the release of 1-2 billion tonnes of carbon dioxide equivalent over approximately 90 years. This revenue could be used to reduce the costs of improved land management by three quarters or double the number of biodiversity targets achieved and meet carbon storage targets for the same cost. These results are based on generalised cost and carbon data; more comprehensive applications will rely on fine scale, site-specific data and a supportive policy environment. Our research illustrates that the duel objective of conserving biodiversity and reducing the release of greenhouse gases offers important opportunities for cost-effective land management investments.

  19. Electron Loss from 1.4 MeV/u U4,6,10+ Ions Colliding with Ne, N2, and Ar Targets

    CERN Document Server

    Dubois, R D; Stöhlker, T; Bosch, F; Bräuning-Demian, A; Banas, D; Gumberidze, A; Hagmann, S; Kozhuharov, C; Mann, R; Orsic-Muthig, A; Spillmann, U; Tachenov, S; Bart, W; Dahl, L; Franzke, B; Glatz, J; Gröning, L; Richter, S; Wilms, D; Ullmann, K; Jagutzki, O

    2004-01-01

    Absolute, total, single, and multiple electron loss cross sections are measured for 1.4 MeV/u U4,6,10+ ions colliding with neon and argon atoms and nitrogen molecules. It is found that the cross sections all have the same dependence on the number of electrons lost and that multiplying the cross sections by the initial number of electrons in the 6s, 6p, and 5f shells yields good agreement between the different projectiles. By combining the present data with previous measurements made at the same velocity, it is shown that the scaled cross sections slowly decrease in magnitude for incoming charge states between 1 and 10 whereas the cross sections for higher charge state ions fall off much more rapidly.

  20. 14-Thienyl Methylene Matrine (YYJ18, the Derivative from Matrine, Induces Apoptosis of Human Nasopharyngeal Carcinoma Cells by Targeting MAPK and PI3K/Akt Pathways in Vitro

    Directory of Open Access Journals (Sweden)

    Mao Xie

    2014-05-01

    Full Text Available Background/Aims: Nasopharyngeal carcinoma (NPC is a distinctive type of head and neck cancer with the highest incidence in South China. Previous studies have proved that matrine, a main alkaloid isolated from Sophora flavescens Ait, has antitumor activity against NPC. However, the effect is not so pronounced and the underlying mechanism remains largely unclear. Here we investigated whether 14-thienyl methylene matrine (YYJ18 that was derived from matrine could exert more effective suppression activity on NPC, along with the underlying mechanism. Methods: NPC cell lines CNE1, CNE2 and HONE1 were treated with YYJ18. Cell proliferation and apoptosis were determined by MTT assay and flow cytometry. Activation of mitogen-activated protein kinases (MAPK and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt pathways were determined by Western blotting and quantitative RT-PCR. Results: YYJ18 remarkably inhibited proliferation and induced apoptosis of all three NPC cell lines in a dose-dependent manner, especially in CNE2 cells. Furthermore, YYJ18 treatment significantly suppressed phosphorylation of p38 in CNE2 cells, but upregulated phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2 and Akt. Next, alterations in downstream signaling were found, including activation of BCL2-associated X protein (Bax, caspase-3 and inactivation of B-cell CLL/lymphoma 2 (Bcl-2. Conclusion: We demonstrate the potent inhibitory effects of 14-thienyl methylene matrine on NPC cells for the first time, which could be mediated by modulation of MAPK and PI3K/Akt pathways.

  1. Microcapsule carbon nanotube devices for therapeutic applications

    Science.gov (United States)

    Kulamarva, Arun; Raja, Pavan M. V.; Bhathena, Jasmine; Chen, Hongmei; Talapatra, Saikat; Ajayan, Pulickel M.; Nalamasu, Omkaram; Prakash, Satya

    2009-01-01

    Carbon nanotubes are a new class of nanomaterials that have immense potential in the field of biomedicine. Their ability to carry large quantities of therapeutic molecules makes them prime candidates for providing targeted delivery of therapeutics for use in various diseases. However, their utility is limited due to the problems faced during their delivery to target sites. This article for the first time describes the design of a novel microcapsule carbon nanotube targeted delivery device. This device has potential in the targeted delivery of carbon nanotubes in suitable membranes along with their cargo, safely and effectively to the target loci.

  2. Carbon Ion Therapy

    DEFF Research Database (Denmark)

    Bassler, Niels; Hansen, David Christoffer; Herrmann, Rochus;

    On the importance of choice of target size for selective boosting of hypoxic tumor subvolumina in carbon ion therapy Purpose: Functional imaging methods in radiotherapy are maturing and can to some extent uncover radio resistant structures found within a tumour entity. Selective boost of identified...... effect. All cell lines investigated here did not reach an OER of 1, even for the smaller structures, which may indicate that the achievable dose average LET of carbon ions is too low, and heavier ions than carbon may be considered for functional LET-painting....

  3. 1,4-Diketones from Cross-Conjugated Dienones: Potassium Permanganate-Interrupted Nazarov Reaction.

    Science.gov (United States)

    Kwon, Yonghoon; Schatz, Devon J; West, Frederick G

    2015-08-17

    A domino potassium permanganate-interrupted Nazarov reaction to yield syn-2,3-disubstituted 1,4-diketones via a decarbonylative cleavage of the Nazarov oxyallyl intermediate, believed to be without precedent, is presented. This process allows syn substituents to be established stereospecifically on the 2-carbon bridge connecting the ketone carbonyl carbons, and the formation of one carbon-carbon and two carbon-oxygen bonds. Two carbon-carbon bonds are cleaved in this process. PMID:26138361

  4. The R467K Amino Acid Substitution in Candida albicans Sterol 14α-Demethylase Causes Drug Resistance through Reduced Affinity

    OpenAIRE

    Lamb, David C.; Kelly, Diane E.; White, Theodore C.; Kelly, Steven L.

    2000-01-01

    The cytochrome P450 sterol 14α-demethylase (CYP51) of Candida albicans is involved in an essential step of ergosterol biosynthesis and is the target for azole antifungal compounds. We have undertaken site-directed mutation of C. albicans CYP51 to produce a recombinant mutant protein with the amino acid substitution R467K corresponding to a mutation observed clinically. This alteration perturbed the heme environment causing an altered reduced-carbon monoxide difference spectrum with a maximum ...

  5. Carbon budgets in symbiotic associations

    Energy Technology Data Exchange (ETDEWEB)

    Muscatine, L.; Falkowski, P.G.; Dubinsky, Z.

    1983-01-01

    Methods are described which permit the estimation of daily budgets for photosynthetically fixed carbon in any alga-invertebrate symbiosis. Included is a method for estimating total daily translocation which does not involve the use of C-14. A daily carbon budget for a shallow water symbiotic reef coral is presented.

  6. 14 CFR 14.23 - Reply.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reply. 14.23 Section 14.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURAL RULES RULES IMPLEMENTING THE EQUAL ACCESS TO JUSTICE ACT OF 1980 Procedures for Considering Applications § 14.23 Reply....

  7. 14 CFR 14.27 - Decision.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Decision. 14.27 Section 14.27 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PROCEDURAL RULES RULES IMPLEMENTING THE EQUAL ACCESS TO JUSTICE ACT OF 1980 Procedures for Considering Applications § 14.27...

  8. 14 CFR 380.14 - Unused space.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Unused space. 380.14 Section 380.14 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) SPECIAL REGULATIONS PUBLIC CHARTERS Conditions and Limitations § 380.14 Unused space. Noting contained in this...

  9. Blank corrections for ramped pyrolysis radiocarbon dating of sedimentary and soil organic carbon.

    Science.gov (United States)

    Fernandez, Alvaro; Santos, Guaciara M; Williams, Elizabeth K; Pendergraft, Matthew A; Vetter, Lael; Rosenheim, Brad E

    2014-12-16

    Ramped pyrolysis (RP) targets distinct components of soil and sedimentary organic carbon based on their thermochemical stabilities and allows the determination of the full spectrum of radiocarbon ((14)C) ages present in a soil or sediment sample. Extending the method into realms where more precise ages are needed or where smaller samples need to be measured involves better understanding of the blank contamination associated with the method. Here, we use a compiled data set of RP measurements of samples of known age to evaluate the mass of the carbon blank and its associated (14)C signature, and to assess the performance of the RP system. We estimate blank contamination during RP using two methods, the modern-dead and the isotope dilution method. Our results indicate that during one complete RP run samples are contaminated by 8.8 ± 4.4 μg (time-dependent) of modern carbon (MC, fM ∼ 1) and 4.1 ± 5.5 μg (time-independent) of dead carbon (DC, fM ∼ 0). We find that the modern-dead method provides more accurate estimates of uncertainties in blank contamination; therefore, the isotope dilution method should be used with caution when the variability of the blank is high. Additionally, we show that RP can routinely produce accurate (14)C dates with precisions ∼100 (14)C years for materials deposited in the last 10,000 years and ∼300 (14)C years for carbon with (14)C ages of up to 20,000 years.

  10. Preparation of thin nuclear targets

    International Nuclear Information System (INIS)

    Thin film backings, sources and targets are needed for many applications in low energy nuclear physics and nuclear chemistry experiments. A survey of techniques used in the preparation of nuclear targets is first briefly discussed. These are classified as chemical, mechanical and physical preparations. Vacuum evaporation, being the most generally used technique, is discussed in detail. It is highly desirable to monitor the film thickness and control the deposition rate during evaporation and to measure the final target thickness after deposition has concluded. The relative merits of various thickness measuring techniques are described. Stages in the fabrication and mounting of self-supporting foils are described in detail, with emphasis given to the preparation of thin self-supporting carbon foils used as target backings and stripper foils. Various target backings, and the merits of the more generally used release agents are described in detail. The preparations of more difficult elemental targets are discussed, and a comprehensive list of the common targets is presented

  11. DEVELOPMENT OF DOPED NANOPOROUS CARBONS FOR HYDROGEN STORAGE

    Energy Technology Data Exchange (ETDEWEB)

    Lueking, Angela D.; Li, Qixiu; Badding, John V.; Fonseca, Dania; Gutierrez, Humerto; Sakti, Apurba; Adu, Kofi; Schimmel, Michael

    2010-03-31

    Hydrogen storage materials based on the hydrogen spillover mechanism onto metal-doped nanoporous carbons are studied, in an effort to develop materials that store appreciable hydrogen at ambient temperatures and moderate pressures. We demonstrate that oxidation of the carbon surface can significantly increase the hydrogen uptake of these materials, primarily at low pressure. Trace water present in the system plays a role in the development of active sites, and may further be used as a strategy to increase uptake. Increased surface density of oxygen groups led to a significant enhancement of hydrogen spillover at pressures less than 100 milibar. At 300K, the hydrogen uptake was up to 1.1 wt. % at 100 mbar and increased to 1.4 wt. % at 20 bar. However, only 0.4 wt% of this was desorbable via a pressure reduction at room temperature, and the high lowpressure hydrogen uptake was found only when trace water was present during pretreatment. Although far from DOE hydrogen storage targets, storage at ambient temperature has significant practical advantages oner cryogenic physical adsorbents. The role of trace water in surface modification has significant implications for reproducibility in the field. High-pressure in situ characterization of ideal carbon surfaces in hydrogen suggests re-hybridization is not likely under conditions of practical interest. Advanced characterization is used to probe carbon-hydrogen-metal interactions in a number of systems and new carbon materials have been developed.

  12. Carbonized Micro- and Nanostructures: Can Downsizing Really Help?

    Directory of Open Access Journals (Sweden)

    Mohammad Naraghi

    2014-05-01

    Full Text Available In this manuscript, we discuss relationships between morphology and mechanical strength of carbonized structures, obtained via pyrolysis of polymeric precursors, across multiple length scales, from carbon fibers (CFs with diameters of 5–10 µm to submicron thick carbon nanofibers (CNFs. Our research points to radial inhomogeneity, skin–core structure, as a size-dependent feature of polyacrylonitrile-based CFs. This inhomogeneity is a surface effect, caused by suppressed diffusion of oxygen and stabilization byproducts during stabilization through skin. Hence, reducing the precursor diameters from tens of microns to submicron appears as an effective strategy to develop homogeneous carbonized structures. Our research establishes the significance of this downsizing in developing lightweight structural materials by comparing intrinsic strength of radially inhomogeneous CFs with that of radially homogeneous CNF. While experimental studies on the strength of CNFs have targeted randomly oriented turbostratic domains, via continuum modeling, we have estimated that strength of CNFs can reach 14 GPa, when the basal planes of graphitic domains are parallel to nanofiber axis. The CNFs in our model are treated as composites of amorphous carbon (matrix, reinforced with turbostratic domains, and their strength is predicted using Tsai–Hill criterion. The model was calibrated with existing experimental data.

  13. Conducting carbonized polyaniline nanotubes

    Science.gov (United States)

    Mentus, Slavko; Ćirić-Marjanović, Gordana; Trchová, Miroslava; Stejskal, Jaroslav

    2009-06-01

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 °C min-1 up to a maximum temperature of 800 °C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 µm, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 µm, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm-1, increased to 0.7 S cm-1 upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  14. Conducting carbonized polyaniline nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mentus, Slavko; Ciric-Marjanovic, Gordana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Trchova, Miroslava; Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Square 2, 162 06 Prague 6 (Czech Republic)], E-mail: gordana@ffh.bg.ac.rs

    2009-06-17

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min{sup -1} up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 {mu}m, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 {mu}m, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm{sup -1}, increased to 0.7 S cm{sup -1} upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  15. nsilico biological evaluation of newly synthesized 1'-(4-Br omophenyl-4'- {4-[(2-oxo-1,2,3,4-tetrahydronaphthalen-2-ylidene methyl] phenyl}-3'',4''- dihydroacenaphthylene-1-spiro-2'-pyrrolidine-3'-spi ro-2''-naphthalene- 2,1''(1H,2''H-dione against fungal target

    Directory of Open Access Journals (Sweden)

    Saravanan B

    2014-03-01

    Full Text Available Fungal infection is the commnest problem everywhere. Depending on the types of starin involves the strategy applies. Various spectral antibiotics have been incorporated as antifungals but fail to inhibit. This pilot study establishes the new synthesied compound 1'-(4-Bromophenyl-4'-{4-[(2-oxo-1,2,3,4-tetrahydronaphthalen-2-ylidenemethyl]phenyl}-3'',4''-dihydroacenaphthylene-1-spiro-2'-pyrrolidine-3'-spiro-2''-naphthalene-2,1''(1H,2''H-dione tested against the fungal target. Selected target retrieved from database and selected using biosynthetic pathways by using the cellular mechanism. This can be act as a check point to interrupt the pathway. Newly introduced pyrolidine based compound were dock with the glucose 6 phosphate synthase insilico docking tools and analyzed by X ray crystallography. Docking by molegro virualdocker (MVD shows good docking score and poses. It shows -141kcal/mol in first pose whichconsiders as a based score and structure based binding site. In conclusion, the synthesized compound can designate as drug.

  16. The SPES direct UCx target

    Science.gov (United States)

    Andrighetto, A.; Antonucci, C.; Barbui, M.; Carturan, S.; Cervellera, F.; Cevolani, S.; Cinausero, M.; Colombo, P.; Dainelli, A.; di Bernardo, P.; Gramegna, F.; Maggioni, G.; Meneghetti, G.; Petrovich, C.; Piga, L.; Prete, G.; Rizzi, V.; Tonezzer, M.; Zafiropoulos, D.; Zanonato, P.

    2007-11-01

    A possible solution for a target system aimed at the production of exotic nuclei as a result of high energy fissions in 238U compounds has been analyzed. The proposed configuration is constituted by a primary proton beam (40 MeV, 0.2 mA) directly impinging on uranium carbide disks inserted within a cylindrical carbon box. This system has been conceived to obtain both a high number of neutron rich atoms (originated from about 1013 fissions/s) and a low power deposition in the target. In order to extract the fission fragments, the box has to be hold at 2000○C. The thermal analysis shows the capability of the thermal radiation to cool the disks with a reasonable margin below the material melting point. Moreover, the analyses of the thermo-mechanical behaviour and of the effusion times confirm the promising features of this target configuration.

  17. Influence of organic carbon sources and isotope exchange processes between water and nitrate on the fractionation of the stable isotopes 15N/14N and 18O/16O in dissolved nitrate during microbial dentrification in groundwater

    International Nuclear Information System (INIS)

    Stable isotopes of nitrate are commonly used to determine sources and degradation of nitrate. In this study, nitrite oxidizing bacteria were found to promote an oxygen isotope exchange between water and nitrate under anoxic conditions. Also, different carbon sources were found to influence the enrichment of stable isotopes in nitrate during microbial denitrification. Both results refine the stable isotope model of nitrate in respect to nitrate source determination and microbial nitrate reduction.

  18. Impact of Different Carbon Policies on City Logistics Network

    Directory of Open Access Journals (Sweden)

    Yang Jianhua

    2015-01-01

    Full Text Available A programming model for a four-layer urban logistics distribution network is constructed and revised based on three types of carbon emissions policies such as Carbon tax, carbon emissions Cap, Carbon Trade. Effects of different policies on logistics costs and carbon emissions are analyzed based on a spatial Logistics Infrastructure layout of Beijing. Research findings are as follows: First, based on low-carbon policies, the logistics costs and carbon emissions can be changed by different modes of transport in a certain extent; second, only when carbon taxes and carbon trading prices are higher, carbon taxes and carbon trading policies can reduce carbon emissions while not significantly increase logistics costs at the same time, and more effectively achieve carbon reduction targets than use carbon cap policy.

  19. SunShot solar power reduces costs and uncertainty in future low-carbon electricity systems.

    Science.gov (United States)

    Mileva, Ana; Nelson, James H; Johnston, Josiah; Kammen, Daniel M

    2013-08-20

    The United States Department of Energy's SunShot Initiative has set cost-reduction targets of $1/watt for central-station solar technologies. We use SWITCH, a high-resolution electricity system planning model, to study the implications of achieving these targets for technology deployment and electricity costs in western North America, focusing on scenarios limiting carbon emissions to 80% below 1990 levels by 2050. We find that achieving the SunShot target for solar photovoltaics would allow this technology to provide more than a third of electric power in the region, displacing natural gas in the medium term and reducing the need for nuclear and carbon capture and sequestration (CCS) technologies, which face technological and cost uncertainties, by 2050. We demonstrate that a diverse portfolio of technological options can help integrate high levels of solar generation successfully and cost-effectively. The deployment of GW-scale storage plays a central role in facilitating solar deployment and the availability of flexible loads could increase the solar penetration level further. In the scenarios investigated, achieving the SunShot target can substantially mitigate the cost of implementing a carbon cap, decreasing power costs by up to 14% and saving up to $20 billion ($2010) annually by 2050 relative to scenarios with Reference solar costs.

  20. SunShot solar power reduces costs and uncertainty in future low-carbon electricity systems.

    Science.gov (United States)

    Mileva, Ana; Nelson, James H; Johnston, Josiah; Kammen, Daniel M

    2013-08-20

    The United States Department of Energy's SunShot Initiative has set cost-reduction targets of $1/watt for central-station solar technologies. We use SWITCH, a high-resolution electricity system planning model, to study the implications of achieving these targets for technology deployment and electricity costs in western North America, focusing on scenarios limiting carbon emissions to 80% below 1990 levels by 2050. We find that achieving the SunShot target for solar photovoltaics would allow this technology to provide more than a third of electric power in the region, displacing natural gas in the medium term and reducing the need for nuclear and carbon capture and sequestration (CCS) technologies, which face technological and cost uncertainties, by 2050. We demonstrate that a diverse portfolio of technological options can help integrate high levels of solar generation successfully and cost-effectively. The deployment of GW-scale storage plays a central role in facilitating solar deployment and the availability of flexible loads could increase the solar penetration level further. In the scenarios investigated, achieving the SunShot target can substantially mitigate the cost of implementing a carbon cap, decreasing power costs by up to 14% and saving up to $20 billion ($2010) annually by 2050 relative to scenarios with Reference solar costs. PMID:23865424