Selection of a carbon-14 fixation form

International Nuclear Information System (INIS)

Scheele, R.D.; Burger, L.L.

1982-09-01

This report summarizes work on the selection of a disposal form for carbon-14 produced during the production of nuclear power. Carbon compounds were screened on the basis of solubility, thermal stability, resistance to oxidation, cost and availability, compatibility with the selected disposal matrix, leach resistance when incorporated in concrete, and compatibility with capture technologies. Carbonates are the products of the various technologies presently considered for carbon-14 capture. The alkaline earth carbonates exhibit the greatest thermal stabilities, lowest solubilities, lowest raw material cost, and greatest raw material availabilities. When reactions with cement and its impurities are considered, calcium and strontium carbonates are the only alkaline earth carbonates resistant to hydrolysis and reaction with sulfate. Leaching tests of barium, calcium, lead, potassium, and strontium carbonates in concrete showed calcium carbonate concrete to be slightly superior to the other alkaline earth carbonates, and greatly superior to a soluble carbonate, potassium carbonate, and lead carbonate. None of the additives to the concrete reduced the carbonate leaching. Acidic CO 2 -containing waters were found to greatly increase carbonate leaching from concrete. Sea water was found to leach less carbon from carbonate concretes than either distilled water or Columbia River water, which showed nearly equivalent leaching. Based on our work, calcium, barium, and strontium carbonates in concrete are the most suitable waste forms for carbon-14, with calcium carbonate concrete slightly superior to the others. If the waste form is to be exposed to natural waters, sea water will have the lowest leach rate. 6 figures, 7 tables

Synthesis of carbon-13 and carbon-14 labeled paldimycin tri-sodium salt

International Nuclear Information System (INIS)

Hsi, R.S.P.; Witz, D.F.; Visser, J.; Stolle, W.T.; Ditto, C.L.

1989-01-01

Carbon-14 labeled paldimycin trisodium salt was prepared by addition of N-acetyl-L-cysteine to [ 14 C]paulomycin, the radioactive antibiotic produced by fermentation of Streptomyces paulus in the presence of L-methionine labeled with carbon-14 in the S-methyl group. Carbon-13 nuclear magnetic resonance (NMR) spectra of paulomycin produced when the fermentation was carried out in the presence of L-[S-methyl- 13 C]methionine showed that the isotope incorporation had occurred specifically at the methoxy group of ring C, i.e., the 2-deoxy sugar portion of paulomycin. With sustained slow feed of labeled precursors during the optimum antibiotic production period, carbon-14 isotope yields of up to 17.5% with specific activity of up to 11.4 μCi per milligram of paulomycin, and carbon-13 isotope yields of up to 24% with 17-fold isotope enrichment over natural abundance, were achieved. (author)

The EC CAST project (carbon-14 source term)

International Nuclear Information System (INIS)

Williams, S. J.

2015-01-01

Carbon-14 is a key radionuclide in the assessment of the safety of underground geological disposal facilities for radioactive wastes. It is possible for carbon-14 to be released from waste packages in a variety of chemical forms, both organic and inorganic, and as dissolved or gaseous species The EC CAST (CArbon-14 Source Term) project aims to develop understanding of the generation and release of carbon-14 from radioactive waste materials under conditions relevant to packaging and disposal. It focuses on the release of carbon-14 from irradiated metals (steels and zirconium alloys), from irradiated graphite and from spent ion-exchange resins. The CAST consortium brings together 33 partners. CAST commenced in October 2013 and this paper describes progress to March 2015. The main activities during this period were reviews of the current status of knowledge, the identification and acquisition of suitable samples and the design of experiments and analytical procedures. (authors)

Carbon-14 measurements in aquifers with methane

International Nuclear Information System (INIS)

Barker, J.F.; Fritz, P.; Brown, R.M.

1979-01-01

A survey of various groundwater systems indicates that methane is a common trace constituent and occasionally a major carbon species in groundwaters. Thermocatalytic methane had delta 13 Csub(CH 4 )>-45 per mille and microbially produced or biogenic methane had delta 13 Csub(CH 4 ) 13 C values for the inorganic carbon. Thermocatalytic methane had no apparent effect on the inorganic carbon. Because methanogenesis seriously affects the carbon isotope geochemistry of groundwaters, the correction of raw 14 C ages of affected groundwaters must consider these effects. Conceptual models are developed which adjust the 14 C activity of the groundwater for the effects of methanogenesis and for the dilution of carbon present during infiltration by simple dissolution of rock carbonate. These preliminary models are applied to groundwaters from the Alliston sand aquifer where methanogenesis has affected most samples. In this system, methanogenic bacteria using organic matter present in the aquifer matrix as substrate have added inorganic carbon to the groundwater which has initiated further carbonate rock dissolution. These processes have diluted the inorganic carbon 14 C activity. The adjusted groundwater ages can be explained in terms of the complex hydrogeology of this aquifer, but also indicate that these conceptual models must be more rigorously tested to evaluate their appropriateness. (author)

Carbon-14 in tree rings

International Nuclear Information System (INIS)

Cain, W.F.; Suess, H.E.

1976-01-01

In order to investigate how reliably the carbon 14 content of tree rings reflects that of atmospheric carbon dioxide, two types of determinations were carried out: (1) carbon 14 determinations in annual rings from the beginning of this century until 1974 and (2) carbon 14 determinations in synchronous wood from the North American bristlecone pine and from European oak trees, dendrochronologically dated to have grown in the third and fourth century B.C. The first series of measurements showed that bomb-produced radiocarbon was incorporated in wood at a time when it was converted from sapwood to heartwood, whenever radiocarbon from bomb testing was present in the atmosphere. The second series showed that wood more than 2000 years old and grown on two different continents at different altitudes had, within the limits of experimental error, the same radiocarbon content. This work and other experimental evidence, obtained in part by other laboratories, show that tree rings reflect the average radiocarbon content of global atmospheric carbon dioxide accurately within several parts per mil. In rare cases, deviations of up to 10 parts per thousand may be possible. This means that a typical single radiocarbon date for wood or charcoal possesses an intrinsic uncertainty (viz., an estimated ''one-sigma error'' in addition to all the other errors) of the order of +-50 years. This intrinsic uncertainty is independent of the absolute age of the sample. More accurate dates can, in principle, be obtained by the so-called method of ''wiggle matching.''

Distribution of carbon-14 assimilated by wheat awns

International Nuclear Information System (INIS)

Olugbemi, L.B.

1978-01-01

The pattern of distribution of carbon assimilated by awns was investigated in two lines of Triticum aestivum. Single awns on basal florets of spikelets in the central part of the ear were dosed with 14 C0 2 . Five days after dosing, 99% of the carbon-14 recovered was in the spikelet bearing the awn. Of the carbon-14 exported from the treated awn 57% went to the grain of the first floret, 1% to the second, 28% to the third and 7% to the fourth. (author)

Carbon-14 production in nuclear reactors

International Nuclear Information System (INIS)

Davis, W. Jr.

1977-01-01

The radioactive nuclide 14 C is formed in all nuclear reactors due to absorption of neutrons by carbon, nitrogen, or oxygen. These may be present as components of the fuel, moderator, or structural hardware, or they may be present as impurities. Most of the 14 C formed in the fuels or in the graphite of HTGRs will be converted to a gaseous form at the fuel reprocessing plant, primarily as carbon dioxide; this will be released to the environment unless special equipment is installed to collect it and convert it to a solid for essentially permanent storage. If the 14 C is released as carbon dioxide or in any other chemical form, it will enter the biosphere, be inhaled or ingested as food by nearly all living organisms including man, and will thus contribute to the radiation burden of these organisms. Detailed estimates are presented of the amounts of 14 C formed in LWRs, HTGR, and LMFBR with emphasis on those pathways that are likely to lead to the release of this nuclide, either at the reactor site or at the fuel reprocessing plant. 83 references

Dynamics of carbon 14 in soils: a review

International Nuclear Information System (INIS)

Tamponnet, C.

2004-01-01

In terrestrial ecosystems, soil is the main interface between atmosphere, hydrosphere, lithosphere and biosphere. Its interactions with carbon cycle are primordial. Information about carbon 14 dynamics in soils is quite dispersed and an up-to-date status is therefore presented in this paper. Carbon 14 dynamics in soils are governed by physical processes (soil structure, soil aggregation, soil erosion) chemical processes (sequestration by soil components either mineral or organic), and soil biological processes (soil microbes, soil fauna, soil biochemistry). The relative importance of such processes varied remarkably among the various biomes (tropical forest, temperate forest, boreal forest, tropical savannah, temperate pastures, deserts, tundra, marshlands, agro ecosystems) encountered in the terrestrial eco-sphere. Moreover, application for a simplified modelling of carbon 14 dynamics in soils is proposed. (author)

Dual labelling of Lobuprofen with tritium and carbon-14

International Nuclear Information System (INIS)

Santamaria, J.; Rivera, P.; Esteban, M.; Martin, J.L.; Carretero, J.M.

1988-01-01

Dual labelling of Lobuprofen with tritium and carbon-14 was performed. The synthesis between 2-(4-isobutylphenyl)propionic acid (Ibuprofen), randomly labelled with tritium, and 2-[4-(3-chlorophenyl)-1-piperazinyl]ethanol (Cl-Alkanol) labelled with carbon-14 in the piperazine ring was achieved. Prior to this synthesis, the [ 14 C]Cl-Alkanol was obtained using 2-amino-[2- 14 C]ethanol as a precursor. (author)

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 dates...

Carbon-14 geochemistry at the Savannah River Site

International Nuclear Information System (INIS)

Roberts, Kimberly A.; Kaplan, Daniel I.

2013-01-01

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 14 C did not sorbed to sediments or cementitious materials, i.e., that C-14 K 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 14 C as CO 2 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 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 14 C, as dissolved carbonate, sorbs to and desorbs from SRS sediments and cementitious materials. Laboratory studies measuring the sorption of 14 C, added as a carbonate, showed unequivocally that 14 C-carbonate K 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 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 d model, may be a more accurate description of the 14 C-carbonate sorption process. A second study demonstrated that the 14 C-carbonate sorbed very strongly onto the

Investigations into the post-natal development of demethylating enzyme systems by determination of carbon dioxide 14 in the air exhaled by mice after applications of carbon 14 dimethyl amino-antipyrine

International Nuclear Information System (INIS)

Schmidt, H.

1982-01-01

Albino mice were subcutaneously injected with carbon 14 dimethyl aminopyrines, the methyl group of which can be metabolised in the organism into carbon dioxide 14. The following results were obtained: In the carbon dioxide 14 exhalation of neonate, young and adult animals after administration of carbon 14 aminopyrine, distinct differences were noted. The maximum of elimination via the lungs occurs after 20-30 minutes in grown-up mice, in neonates or young animals distinctly later (60-90 min). The carbon dioxide 14 exhalation was also measured after additional subcutaneous application of methrotrexate. In mice aged 8 and 10 days a distinct decrease in carbon dioxide 14 exhalation was found. By contrast, a rise in carbon dioxide 14 exhaled was found in mice aged 2 days. The orientating experiments with folic acid and carbon 14 dimethyl aminopyrine show that leucovorin leads to a distinct increase in carbon dioxide 14 exhalation during the first 30 minutes. As a cause of the different degrees of stimulation respectively inhibition of demethylation, different biochemical ways of formaldehyde formation are pointed out. One of these probably includes the folate-dependent reaction. (orig./MG) [de

Concentration of carbon-14 in plants

International Nuclear Information System (INIS)

1978-01-01

The carbon-14 survey program initiated 1960 to gather data on current levels of carbon-14 in environments. Plants essential oil and fermented alcohol were selected as sample materials. The carbon contained in these materials is fixed from atmospheric carbon dioxide by anabolism, so they well reflect the variation of carbon-14 in biosphere. Thymol; Thymol was obtained from the essential oil of Orthodon Japonicium Benth which was cultivated and harvested every year in the experimental field of NIRS and Chiba University. The methylation was carried out to eliminate the strong quenching action of the phenolic group of thymol. Eighteen grams of thymol methyl ether was used as liquid scintillator by adding 0.4% PPO and 0.01% POPOP. Menthol; Menthol was obtained from Mentha arvensis L which was cultivated in the east part of Hokkaido and prepared by Kitami Factory of Federation of Agricultural Cooperative Society of Hokkaido. The chemical conversion of menthol to p-cymene was carried out and used as liquid scintillator as same as above sample. Lemongrass oil; Lemongrass oil was obtained from Cymbopogon citratus Stapf which was cultivated in Izu Experimental Station of Medicinal Plants, National Institute of Hygienic Science located Minami-Izu, Shizuoka Pref. The p-cymene derived from Lemongrass oil was used as liquid scintillator. Alcohol; All sample of fermented alcohol were obtained from the Alcohol Factories of Ministry of Trade and Industry. Raw materials of alcohol were sweet potatos cultivated in several prefectures in Japan ''high test'' molasses and blackstrap molasses imported from several countries of Asia, South America and South Africa, crude alcohol imported from U.S.A., Argentina and Brazil. Mixed solvent of 10 ml sample alcohol and 10 ml toluene or p-xylene containing 0.8% PPO and 0.1% dimethyl POPOP was used as liquid scintillator. (author)

Study of a method of detection for natural carbon-14 using a liquid scintillator, recent variations in the natural radio-activity due to artificial carbon-14 (1963); Etude d'une methode de detection du carrons 14 naturel, utilisant un scintillateur liquide - variations recentes de l'activite naturelle dues au carbone 14 artificiel (1963)

Energy Technology Data Exchange (ETDEWEB)

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

1963-06-15

Among the various natural isotopes of carbon, a radioactive isotope, carbon-14, is formed by the action of secondary neutrons from cosmic rays on nitrogen in the air. Until 1950, the concentration of this isotope in ordinary carbon underwent weak fluctuations of about 2-3 per cent. The exact measurement of this concentration 6 X 10{sup 12} Ci/gm of carbon, and of its fluctuations, are difficult and in the first part of this report a highly sensitive method is given using a liquid scintillator. Since 1950 this natural activity has shown large fluctuations because of the carbon-14 formed during nuclear explosions, and in the second part, the evolution in France of this specific activity of carbon in the atmosphere and biosphere is examined. In the last part is studied the local increase in carbon activity in the atmosphere around the Saclay site, an increase caused by the carbon-14 given off as C{sup 14}O{sub 2}, by the reactors cooled partially with exterior air. (author) [French] Parmi les differents isotopes naturels du carbone, un isotope radioactif, le carbone 14, est forme par l'action de neutrons secondaires due aux rayons cosmiques sir l'azote de l'air. Jusqu'en 1950, la concentration de cet isotope dans le carbone ordinaire est soumise a des fluctuations de faible amplitude, de l'ordre de 2 a 3 pour cent. Les mesures precises de cette concentration, 6. 10{sup -12} Ci/g de carbone, et de ses fluctuations sont delicates, et dans la premiere partie de ce rapport, on decrit une methode de detection a grande sensibilite utilisant un scintillateur liquide. Depuis 1950, cette activite naturelle subit des fluctuations importantes dues au carbone 14 forme lors des explosions nucleaires, et dans la seconde partie, on examine l'evolution en France de l'activite specifique du carbone de l'atmosphere et ce la biosphere. Dans la derniere partie, on etudie l'accroissement local de l'activite du carbone de l'air aux environs du site de Saclay, accroissement provoque par le

Carbon-14 Graphitization Chemistry

Science.gov (United States)

Miller, James; Collon, Philippe; Laverne, Jay

2014-09-01

Accelerator Mass Spectrometry (AMS) is a process that allows for the analysis of mass of certain materials. It is a powerful process because it results in the ability to separate rare isotopes with very low abundances from a large background, which was previously impossible. Another advantage of AMS is that it only requires very small amounts of material for measurements. An important application of this process is radiocarbon dating because the rare 14C isotopes can be separated from the stable 14N background that is 10 to 13 orders of magnitude larger, and only small amounts of the old and fragile organic samples are necessary for measurement. Our group focuses on this radiocarbon dating through AMS. When performing AMS, the sample needs to be loaded into a cathode at the back of an ion source in order to produce a beam from the material to be analyzed. For carbon samples, the material must first be converted into graphite in order to be loaded into the cathode. My role in the group is to convert the organic substances into graphite. In order to graphitize the samples, a sample is first combusted to form carbon dioxide gas and then purified and reduced into the graphite form. After a couple weeks of research and with the help of various Physics professors, I developed a plan and began to construct the setup necessary to perform the graphitization. Once the apparatus is fully completed, the carbon samples will be graphitized and loaded into the AMS machine for analysis.

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

International Nuclear Information System (INIS)

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

1980-01-01

Adult female and stage V Calanus pacificus were fed 14 C-labeled phytoplankton in the laboratory in the form of monospecific cultures and natural populations. A carbon budget was constructed by following the 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

Carbon 14 and tritium radioactivity of alcohols

International Nuclear Information System (INIS)

Guerain, J.; Tourliere, S.

1975-01-01

The method of measuring carbon 14 radioactivity of alcohols has been perfected in order to establish the correct determination of synthetic alcohol added to fermentation alcohol. The specific carbon and tritium activity of alcohol of different origins have been determined for 1973 and 1974. The Suess effect and nuclear fall-out are observed [fr

Study of a method of detection for natural carbon-14 using a liquid scintillator, recent variations in the natural radio-activity due to artificial carbon-14 (1963); Etude d'une methode de detection du carrons 14 naturel, utilisant un scintillateur liquide - variations recentes de l'activite naturelle dues au carbone 14 artificiel (1963)

Energy Technology Data Exchange (ETDEWEB)

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

1963-06-15

Among the various natural isotopes of carbon, a radioactive isotope, carbon-14, is formed by the action of secondary neutrons from cosmic rays on nitrogen in the air. Until 1950, the concentration of this isotope in ordinary carbon underwent weak fluctuations of about 2-3 per cent. The exact measurement of this concentration 6 X 10{sup 12} Ci/gm of carbon, and of its fluctuations, are difficult and in the first part of this report a highly sensitive method is given using a liquid scintillator. Since 1950 this natural activity has shown large fluctuations because of the carbon-14 formed during nuclear explosions, and in the second part, the evolution in France of this specific activity of carbon in the atmosphere and biosphere is examined. In the last part is studied the local increase in carbon activity in the atmosphere around the Saclay site, an increase caused by the carbon-14 given off as C{sup 14}O{sub 2}, by the reactors cooled partially with exterior air. (author) [French] Parmi les differents isotopes naturels du carbone, un isotope radioactif, le carbone 14, est forme par l'action de neutrons secondaires due aux rayons cosmiques sir l'azote de l'air. Jusqu'en 1950, la concentration de cet isotope dans le carbone ordinaire est soumise a des fluctuations de faible amplitude, de l'ordre de 2 a 3 pour cent. Les mesures precises de cette concentration, 6. 10{sup -12} Ci/g de carbone, et de ses fluctuations sont delicates, et dans la premiere partie de ce rapport, on decrit une methode de detection a grande sensibilite utilisant un scintillateur liquide. Depuis 1950, cette activite naturelle subit des fluctuations importantes dues au carbone 14 forme lors des explosions nucleaires, et dans la seconde partie, on examine l'evolution en France de l'activite specifique du carbone de l'atmosphere et ce la biosphere. Dans la derniere partie, on etudie l'accroissement local de l'activite du carbone de l'air aux

Synthesis of carbon-14 labelled ethyl chloride

International Nuclear Information System (INIS)

Kanski, R.

1976-01-01

A new efficient method of synthesis of ethyl chloride (1,2- 14 C), based on the Ba 14 CO 3 and dry hydrogen chloride as starting materials has been developed and described. Addition of the hydrogen chloride to ethylene (1,2- 14 C), obtained from Ba 14 CO 3 , has been carried out in the presence of the AlCl 3 as catalyst. The outlined method leads to ethyl chloride (1,2- 14 C) of high specific activity. The radiochemical yield of the reaction based on the activity of barium carbonate used was 72%. (author)

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

Carbon-14 dating of groundwater under Christchurch, 1976 samples

International Nuclear Information System (INIS)

Stewart, M.K.; Brenninkmeijer, C.A.M.; Brown, L.J.

1986-06-01

Four samples of groundwater from deep aquifers under Christchurch have been analysed for carbon-14, tritium, oxygen-18 and chemical contents. Interpretation of the carbon-14 results requires two steps, (1) correction of the measured 14 C values for input of dead ( 14 C-free) carbon underground (indicating that the measured values of 80 PMC* should be increased to about 120 PMC), and (2) determination of water residence times for given flow models of the groundwater system. Interpretation of tritium results involves step 2 only. Three models are considered, of which the third is considered most appropriate to Christchurch. In this model, the 14 C and T results indicate that a small proportion of young water (post-1954) mixes with a larger proportion of older water (probably at least several hundred years). The oxygen-18 content indicates that recharge is mainly from the Waimakariri River and possibly from rainfall and streams near the foothills of the Canterbury Plains. Other aspect of the groundwater flow under Christchurch are discussed

Preparation of 14C-labelled poly(l-menthyl isopropenyl carbonates)

International Nuclear Information System (INIS)

Comes, R.A.; Grubbs, H.J.

1981-01-01

The synthesis of 14 C-labelled poly(l-menthyl isopropenyl carbonate) is described. Experimental conditions are included for incorporation of 14 C into each of the carbon atoms in the molecule. High pressure liquid chromatography conditions are given for separation and purification of the labelled intermediates. (author)

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

International Nuclear Information System (INIS)

Lysakova, Katerina; Neumann, Jan; Vonkova, Katerina

2012-09-01

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 17 O and nitrogen 14 N 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 (CH 4 and CO 2 ) 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

Environmental release of carbon-14 gas from a hypothetical nuclear waste repository

International Nuclear Information System (INIS)

Lehto, M.A.; Merrell, G.B.

1994-01-01

Radioisotopes may form gases in a spent nuclear fuel waste package due to elevated temperatures or degradation of the fuel rods. Radioactive carbon-14, as gaseous carbon dioxide, is one of the gaseous radioisotopes of concern at an underground disposal facility for spent nuclear fuel and high-level radioactive waste. Carbon-14 dioxide may accumulate inside an intact waste container. Upon breach of the container, a potentially large pulse of carbon-14 dioxide gas may be released to the surrounding environment, followed by a lower, long-term continuous release. If the waste were disposed of in an unsaturated geologic environment, the carbon-14 gas would begin to move through the unsaturated zone to the accessible environment. This study investigates the transport of radioactive carbon-14 gas in geologic porous media using a one-dimensional analytical solution. Spent nuclear fuel emplaced in a deep geologic repository located at a generic unsaturated tuff site is analyzed. The source term for the carbon-14 gas and geologic parameters was obtained from previously published materials. The one-dimensional analytical solution includes diffusion, advection, radionuclide retardation, and radioactive decay terms. Two hypothetical sites are analyzed. One is dominated by advective transport, and the other is dominated by diffusive transport. The dominant transport mechanism at an actual site depends on the site characteristics. Results from the simulations include carbon-14 dioxide travel times to the accessible environment and the total release to the environment over a 10,000-year period. The results are compared to regulatory criteria

Determination of carbon-14 environmental samples by mixing 14CO2 with a liquid scintillator

International Nuclear Information System (INIS)

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

1990-01-01

A method for the determination of Carbon-14 ( 14 CO 2 ) 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-CO 2 ) to the liquid scintillator. The results obtained to apply this method and the benzene synthesis, usual in our laboratory, are discused and compared. The method of collection of atmospheric samples is also described. (Author)

Synthesis of carbon-14 labeled vigabatrin. [Antieplileptic

Energy Technology Data Exchange (ETDEWEB)

Schuster, A.J.; Wagner, E.R. (Marion Merrell Dow Inc, Indianapolis, IN (United States))

1993-01-01

Carbon-14 labeled vigabatrin was synthesized in 5 steps from 5-hydroxymethyl-2-pyrrolidone tosylate and NaCN-[[sup 14]C]. A key step involved reduction of the resulting nitrile in the presence of excess dimethylamine to give the dimethylamino-ethyl 2-pyrrolidone derivative in one step. This afforded an overall radiochemical yield of 22% and radiochemical purity greater than 98%. (Author).

The preparation of glucose uniformly labelled with carbon-14

International Nuclear Information System (INIS)

Garcia Pineda, M.D.; Suarez Contreras, C.; Rodrigo Gonzalez, M.E.

1978-01-01

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 2 produced from 14 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

Carbon-14 labeling of phytoplankton carbon and chlorophyll a carbon: determination of specific growth rates

International Nuclear Information System (INIS)

Welschmeyer, N.A.; Lorenzen, C.J.

1984-01-01

The pattern of photosynthetic 14 C labeling over time is described for phytoplankton. The carbon-specific growth rate (d -1 ) is defined explicitly by changes in the specific activity (dpm μg -1 C) of the algae. For Skeletonema costatum, growing in axenic batch culture, the specific activities of both total cellular carbon and chlorophyll carbon increase at equal rates and the change in specific activity with time follows the predicted pattern. The specific activity of 14 C-labeled chlorophyll a was used to estimate phytoplankton growth rates and C:Chl ratios of field samples in Dabob Bay (Puget Sound), Washington. Growth rates decreased with depth and C:Chl ratios were higher for samples incubated under high light intensity. In several instances the C:Chl ratio increased from the beginning to the end of the incubation; this trend was most conspicuous near surface light intensities and for days of high total incident radiation. On these occasions, Chl a was actively 14 C labeled, yet little (or even negative) change was noted in the concentration of Chl a. These results suggest that some process (or processes) of chlorophyll degradation must be active at the same time that chlorophyll is being synthesized

The synthesis of SL-75.212 (Betaxolol) labelled with carbon 14: 1-[4-(2-cyclopropyl methoxyethyl-[1-14C]) phenoxy]-3-isopropyl amino-2-propanol

International Nuclear Information System (INIS)

Aubert, F.; Beaucourt, J.P.; Pichat, L.

1982-01-01

Carbonation with 14 CO 2 of the Grigard reagent 1 gave 4-benzyloxy [carboxyl- 14 C] benzoic acid: 2 (87 % yield). 2 was successively treated in diethyl ether solution with diazomethane and lithium aluminium hydride giving rise to [7- 14 C] 4 benzyloxybenzyl alcohol 4 (82 % yield). Alcohol 4 was transformed into the corresponding chloride 5 when exposed to thionylchloride in ether. 5 was condensed with NaCN in DMF to give the nitrile 6 which was hydrolysed into the acid 7 isolated in a 75 % overall yield from Ba 14 CO 3 . 7 gave the alcohol 9 by successive treatments with diazomethane and LiAlH 4 in ether. 9 with NaH gave the corresponding alkoxide which when condensed with bromomethylcyclopropane gave the ether 10 purified by silicagel column chromatography and isolated with an overall yield of 71 % from Ba 14 CO 3 . Hydrogenolysis of 10 gave the phenol 11. The epoxide 12 was secured by condensation with epichlorhydrin in presence of NaOH. After purification by silicagel column chromatography 10 was opened with isopropylamine leading to the target compound BETAXOLOL 13 isolated as the hydrochloride. After extensive purification by Sephadex G-10 column chromatography, SL 75.212 [ethyl-1- 14 C] was obtained in an overall yield of 26 % from barium [ 14 C] carbonate and a radiochemical purity better than 99 % (specific activity 57 mCi/mole). (author)

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

International Nuclear Information System (INIS)

Shukla, Priyadarshi R.; Chaturvedi, Vaibhav

2012-01-01

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.

Monitoring and removal of gaseous carbon-14 species

International Nuclear Information System (INIS)

Kabat, M.J.

1979-01-01

A simple and efficient method was developed for the monitoring of low level carbon-14 in nuclear power station areas and gaseous effluent. Gaseous carbon compounds (hydrocarbons and CO) are catalytically oxidized to CO 2 , which is then absorbed on solid Ca(OH) 2 at elevated temperatures. The 14 C collected is quantitatively liberated by thermal decomposition of CaCO 3 as CO 2 , which is either measured directly by flow-through detectors or absorbed in alkali hydroxide followed by liquid scintillation counting. The method can also be used for the removal of gaseous 14 C. The Ca 14 CO 3 can be immobilized in concrete for long term disposal. Ca(OH) 2 is an inexpensive absorber. It is selective for CO 2 and has high capacity and efficiency for its absorption and retention. A theoretical evaluation of thee optium conditions for CO 2 absorption and liberation is discussed and experimental investigations are described. There is good agreement between theoretical predictions and experimental findings

Synthesis of carbon-14 analogue of 1,5 diaryl-5-[14C]-1,2,3-triazoles

International Nuclear Information System (INIS)

Matloubi, Hojatollah; Shafiee, Abbas; Saemian, Nader; Shirvani, Gholamhossein; Daha, Fariba Johari

2004-01-01

Two 1,2,3-triazole anticonvulsants, 1-(4-methylsulfone-phenyl)-5-(4-methyl-phenyl)-1,2,3-triazole and 1-(4-methylsulfone-phenyl)-5-phenyl-1,2,3-triazole, both labeled with carbon-14 in the 5-position were prepared from para-tolunitrile-[cyano- 14 C] and benzonitrile-[cyano- 14 C], respectively

Determination of Carbon-14 in environmental samples by mixing 14CO2 with a liquid scintillator

International Nuclear Information System (INIS)

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

1990-01-01

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

On the Chinese Carbon Reduction Target

Directory of Open Access Journals (Sweden)

Michinori Uwasu

2010-06-01

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

An improved synthesis of carbon-14 labelled carboxylic acids from carbon-14 labelled amino acids

International Nuclear Information System (INIS)

Ramamurthy, T.V.; Ravi, S.; Viswanathan, K.V.

1988-01-01

Various carbon-14 labelled amino acids including the aromatic ones viz., tyrosine, phenylalanine and tryptophan are converted to the corresponding carboxylic acids in high yield (70-90%) on a micromolar scale synthesis by reaction with hydroxyl-amine-O-sulphonic acid and in a short reaction time. The improvement in yield has been achieved by using aqeuous alcohol as solvent in lieu of water alone as the medium of reaction. (author)

The metabolism and dosimetry of carbon-14 labelled compounds

International Nuclear Information System (INIS)

Crawley, F.E.H.

1977-01-01

The number of compounds labelled at high specific activity with carbon-14 has greatly increased over the last few years. There are limited biological data available to enable an assessment of the internal radiation dose and to identify the critical tissues after an intake of such compounds. The ICRP consider two Model Systems for deriving dose. Both Models assume a total elimination of the carbon-14 in the breath and only bone or whole body as critical tissues and are not representative of the majority of the compounds now available. A research programme has been established to study the rate of excretion and tissue distribution of selected carbon-14 labelled compounds in the rat after intravenous injection, pulmonary and gastric intubation and skin absorption. These metabolic data have been used to calculate the committed dose equivalent and maximum permissible annual intake (MPAI) for various tissues in man on the assumption that the experimental data obtained in the rat are true for man. To date potassium 14 C-cyanide and 14 C-methanol have been studied. The values for the MPAI's derived from the doses to individual tissues are more restrictive than values calculated from the whole body doses. The MPAI calculated from excretion data in terms of whole body dose is 31 mCi for 14 C-cyanide and 25 mCi for 14 C-methanol. However, the critical tissue for 14 C-cyanide is the stomach with an MPAI of 1.5 mCi based on a dose of 10.7 rem mCi -1 . This was an order of magnitude greater than the dose to any other region of the GI tract and 5 times that to the testis. The critical organs for 14 C-methanol are the testis (MPAI 2.5 mCi) for males and the ovaries (MPAI 6.2 mCi) for females

Model study of atmospheric transport using carbon 14 and strontium 90 as inert tracers

Science.gov (United States)

Kinnison, D. E.; Johnston, H. S.; Wuebbles, D. J.

1994-10-01

The observed excess carbon 14 in the atmosphere from 1963 to 1970 provides unique, but limited, data up to an altitude of about 35 km for testing the air motions calculated by 11 multidimensional atmospheric models. Strontium 90 measurements in the atmosphere from 1964 to mid-1967 provide data that have more latitude coverage than those of carbon 14 and are useful for testing combined models of air motions and aerosol settling. Model calculations for carbon 14 begin at October 1963, 9 months after the conclusion of the nuclear bomb tests; the initial conditions for the calculations are derived by three methods, each of which agrees fairly well with measured carbon 14 in October 1963 and each of which has widely different values in regions of the stratosphere where there were no carbon 14 measurements. The model results are compared to the stratospheric measurements, not as if the observed data were absolute standards, but in an effort to obtain new insight about the models and about the atmosphere. The measured carbon 14 vertical profiles at 31°N are qualitatively different from all of the models; the measured vertical profiles show a maximum mixing ratio in the altitude range of 20 to 25 km from October 1963 through July 1966, but all modeled profiles show mixing ratio maxima that increase in altitude from 20 km in October 1963 to greater than 40 km by April 1966. Both carbon 14 and strontium 90 data indicate that the models differ substantially among themselves with respect to stratosphere-troposphere exchange rate, but the modeled carbon 14 stratospheric residence times indicate that differences among the models are small with respect to transport rate between the middle stratosphere and the lower stratosphere. Strontium 90 data indicate that aerosol settling is important up to at least 35 km altitude. Relative to the measurements, about three quarters of the models transport carbon 14 from the lower stratosphere to the troposphere too rapidly, and all models

The metabolism and dosimetry of carbon-14 labelled diethylenetriaminepentaacetic acid (DTPA)

International Nuclear Information System (INIS)

Crawley, F.E.H.; Haines, J.W.

1978-01-01

Male rats were given carbon-14 labelled Ca-DTPA either by intravenous injection or by pulmonary intubation. The elimination of the carbon-14 by excretion in urine, faeces and breath was followed, Chromatographic examination of the urine showed that no metabolic degradation of the 14 C-DTPA had occurred. The distribution of activity between lung, kidneys, bone, muscle and GI tract was also followed. The data obtained have been used to assess the radiation dose to man from an intake of 14 C-DTPA on the assumption that the behaviour of 14 C-DTPA in man is the same as in the rat. The results are discussed. (U K.)

Carbon-14 releases from an unsaturated repository: A senseless but expensive dilemma

International Nuclear Information System (INIS)

Pflum, C.G.

1993-01-01

The purpose of the US Environmental Protection Agency (EPA) Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes (40 CFR Part 191 or standards) is to protect public health and safety. The 1985 rule was developed on the basis of the assumption that the repository would be located in a geologic formation that lies below the water table. It is appropriate to examine gaseous releases and transport of pollutants in order to determine site adequacy. When the provisions of the 1985 standard are applied to Yucca Mountain, specifically the limits for carbon-14, we can release in 10,000 years no more than 7,000 curies of carbon-14 in the form of carbon dioxide. Meanwhile, the US Department of Energy (DOE) and others indicate that the repository may release about 8,000 curies of carbon-14 dioxide, an amount that exceeds the standard by 10 to 20 percent. The original basis of the 1985 standards was that, in a site below the water table, the limit for carbon-14 was technically achievable. It was not a standard based on a release level that would prevent a danger to public health. If we examine the danger to public health of the release of 8,000 curies of carbon-14 dioxide during and 8,000-year period, this release would not a pose a significant threat to the average individual. Industry and natural sources release many times this amount of carbon-14 dioxide each year. The question therefore becomes: is it appropriate to spend an additional $3.2 billion on waste packages when the expenditure does not measurably improve the public health?

Synthesis of carbon-14 analogue of 1,5 diaryl-5-[{sup 14}C]-1,2,3-triazoles

Energy Technology Data Exchange (ETDEWEB)

Matloubi, Hojatollah E-mail: hmatloubi@aeoi.org.ir; Shafiee, Abbas; Saemian, Nader; Shirvani, Gholamhossein; Daha, Fariba Johari

2004-05-01

Two 1,2,3-triazole anticonvulsants, 1-(4-methylsulfone-phenyl)-5-(4-methyl-phenyl)-1,2,3-triazole and 1-(4-methylsulfone-phenyl)-5-phenyl-1,2,3-triazole, both labeled with carbon-14 in the 5-position were prepared from para-tolunitrile-[cyano-{sup 14}C] and benzonitrile-[cyano-{sup 14}C], respectively.

Hydrogen Transfer from Hantzsch 1,4-Dihydropyridines to Carbon-Carbon Double Bonds under Microwave Irradiation

OpenAIRE

Jean Jacques Vanden Eynde; Didier Barbry; Guy Cordonnier; Séverine Torchy

2002-01-01

1,4-Dihydropyridines (DHPs) have been used in the reduction of carbon-carbon double bonds under microwave irradiation without solvent. The efficiency of the reactions is dramatically dependent on the steric effects in the DHPs and on the electronic effects in the olefins.

Carbon-14 dating of tree rings for tritium measurement

International Nuclear Information System (INIS)

Yamada, Y.; Yasuike, K.; Kiriyama, N.; Komura, K.; Ueno, K.

1998-01-01

The carbon-14 concentration in tree-ring cellulose of an 80-year-old pine tree which has been used for tritium measurement was measured during the 1941-1987 period. This was done to determine the formation year of each tree ring in order to study the pathway of tritium uptake into the tree rings. In the 1941 to 1953 period, the δ 14 C value remained slightly lower than 0 per mille. It began to increase from 1954 to a small broad peak of 250 per mille between 1959 and 1961, followed by rapid increase to the highest value of approximately 800 per mille in 1964. Since 1964, it had been diminishing year by year to reach a level of 190 per mille in 1987. The two peak years coincided with those in the known carbon-14 patterns in tree rings. However, there existed a difference in the amplitude of the δ 14 C values during the period of 1963-1967. (author)

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.)

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

International Nuclear Information System (INIS)

Gruhlke, J.M.; Meyer, G.L.; Neiheisel, J.

1987-01-01

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

Preparation of pyridostigmine bromide labeled with carbon-14 and tritium

Energy Technology Data Exchange (ETDEWEB)

Kepler, J.A.; Twine, C.E.; Austin, R.D. (Research Triangle Inst., Research Triangle Park, NC (United States))

1992-08-01

[2-[sup 14]C]Pyridostigmine bromide was prepared in 17.6% radiochemical yield with specific activity of 18 mCi/mmol. The reaction sequence involved preparation of 2-furan[[sup 14]C]carboxylic acid by carbonation of 2-lithiofuran, followed by conversion to 2-amino[[sup 14]C]methylfuran by lithium aluminium hydride reduction of its carboxamide. Oxidative rearrangement of 2-amino[[sup 14]C]methylfuran gave 3-hydroxy[2-[sup 14]C]pyridine which was converted to [2-[sup 14]C]pyridostigmine bromide by reaction with dimethylcarbamyl chloride and quarternization with bromomethane. Pyridostigmine bromide labeled in the methyl group of the carbamate function was prepared in 73% yield with specific activity of 37.6 mCi/mmol by reaction of bis-3-pyridyl carbonate with [[sup 14]C]dimethylamine followed by quarternization with bromomethane. [6-[sup 3]H]-Pyridostigmine bromide with specific activity of 22.5 mCi/mmol was prepared by catalytic halogen-tritium replacement of 2,6-dibromo-3-dimethylcarbamyloxypyridine followed by quarternization with bromomethane and back-exchanging the labile 2-tritium. (author).

Preparation of pyridostigmine bromide labeled with carbon-14 and tritium

International Nuclear Information System (INIS)

Kepler, J.A.; Twine, C.E.; Austin, R.D.

1992-01-01

[2- 14 C]Pyridostigmine bromide was prepared in 17.6% radiochemical yield with specific activity of 18 mCi/mmol. The reaction sequence involved preparation of 2-furan[ 14 C]carboxylic acid by carbonation of 2-lithiofuran, followed by conversion to 2-amino[ 14 C]methylfuran by lithium aluminium hydride reduction of its carboxamide. Oxidative rearrangement of 2-amino[ 14 C]methylfuran gave 3-hydroxy[2- 14 C]pyridine which was converted to [2- 14 C]pyridostigmine bromide by reaction with dimethylcarbamyl chloride and quarternization with bromomethane. Pyridostigmine bromide labeled in the methyl group of the carbamate function was prepared in 73% yield with specific activity of 37.6 mCi/mmol by reaction of bis-3-pyridyl carbonate with [ 14 C]dimethylamine followed by quarternization with bromomethane. [6- 3 H]-Pyridostigmine bromide with specific activity of 22.5 mCi/mmol was prepared by catalytic halogen-tritium replacement of 2,6-dibromo-3-dimethylcarbamyloxypyridine followed by quarternization with bromomethane and back-exchanging the labile 2-tritium. (author)

An integrated approach to geological disposal of UK wastes containing carbon-14

International Nuclear Information System (INIS)

Vines, Sarah; Lever, David

2013-01-01

Carbon-14 is a key radionuclide in the assessment of the safety of a geological disposal facility for radioactive waste because of the calculated assessment of the radiological consequences of gaseous carbon-14 bearing species [i]. It may be that such calculations are based on overly conservative assumptions and that better understanding could lead to considerably reduced assessment of the radiological consequences from these wastes. Alternatively, it may be possible to mitigate the impact of these wastes through alternative treatment, packaging or design options. The Radioactive Waste Management Directorate of the UK's Nuclear Decommissioning Authority (NDA RWMD) has established an integrated project team in which the partners are working together to develop a holistic approach to carbon-14 management in the disposal system [ii]. For a waste stream containing carbon-14 to be an issue: There must be a significant inventory of carbon-14 in the waste stream; and That waste stream has to generate carbon-14 bearing gas; and a bulk gas phase has to entrain the carbon-14 bearing gas: and these gases must migrate through the engineered barriers in significant quantities; and these gases must migrate through the overlying geological environment (either as a distinct gas phase or as dissolved gas); and these gases must interact with materials in the biosphere (i.e. plants) in a manner that leads to significant doses and risks to exposed groups or potentially exposed groups. The project team has developed and used this 'and' approach to structure and prioritise the technical work and break the problem down in a manageable way. We have also used it to develop our approach to considering alternative treatment, packaging and design options. For example, it may be possible to pre-treat some wastes to remove some of the inventory or to segregate other wastes so that they are removed from any bulk gas phase which might facilitate migration through the geosphere

An integrated approach to geological disposal of UK wastes containing carbon-14

Energy Technology Data Exchange (ETDEWEB)

Vines, Sarah [Nuclear Decommissioning Authority, Harwell, Oxfordshire (United Kingdom); Lever, David [AMEC, Harwell, Oxfordshire (United Kingdom)

2013-07-01

Carbon-14 is a key radionuclide in the assessment of the safety of a geological disposal facility for radioactive waste because of the calculated assessment of the radiological consequences of gaseous carbon-14 bearing species [i]. It may be that such calculations are based on overly conservative assumptions and that better understanding could lead to considerably reduced assessment of the radiological consequences from these wastes. Alternatively, it may be possible to mitigate the impact of these wastes through alternative treatment, packaging or design options. The Radioactive Waste Management Directorate of the UK's Nuclear Decommissioning Authority (NDA RWMD) has established an integrated project team in which the partners are working together to develop a holistic approach to carbon-14 management in the disposal system [ii]. For a waste stream containing carbon-14 to be an issue: There must be a significant inventory of carbon-14 in the waste stream; and That waste stream has to generate carbon-14 bearing gas; and a bulk gas phase has to entrain the carbon-14 bearing gas: and these gases must migrate through the engineered barriers in significant quantities; and these gases must migrate through the overlying geological environment (either as a distinct gas phase or as dissolved gas); and these gases must interact with materials in the biosphere (i.e. plants) in a manner that leads to significant doses and risks to exposed groups or potentially exposed groups. The project team has developed and used this 'and' approach to structure and prioritise the technical work and break the problem down in a manageable way. We have also used it to develop our approach to considering alternative treatment, packaging and design options. For example, it may be possible to pre-treat some wastes to remove some of the inventory or to segregate other wastes so that they are removed from any bulk gas phase which might facilitate migration through the geosphere

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.

ORIGIN OF PALMITIC ACID CARBON IN PALMITATES FORMED FROM HEXADECANE-1-C14 AND TETRADECANE-1-C14 BY MICROCOCCUS CERIFICANS

Science.gov (United States)

Finnerty, W. R.; Kallio, R. E.

1964-01-01

Finnerty, W. R. (University of Iowa, Iowa City), and R. E. Kallio. Origin of palmitic acid carbon in palmitates formed from hexadecane-1-C14 and tetradecane-1-C14 by Micrococcus cerificans. J. Bacteriol. 87:1261–1265. 1964.—Degradation of the palmitic acid moiety of cetyl palmitate and myristyl palmitate formed from hexadecane-1-C14 and tetradecane-1-C14 by Micrococcus cerificans was carried out. The patterns of C14 labeling in palmitic acid from cetyl palmitate showed that hexadecane is oxidized at the C1 position, and cetyl alcohol and palmitic acid thus formed are directly esterified. Palmitic acid arising from tetradecane and esterified to tetradecanol appeared to have been synthesized by the addition of two carbon atoms to an existing 14-carbon atom skeleton. Considerable mixing of C14 occurred in the C1 and C2 positions of palmitic acid thus synthesized. PMID:14188700

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)

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

International Nuclear Information System (INIS)

Li Hongqiang; Wang Limao; Shen Lei; Chen Fengnan

2012-01-01

Appraising low carbon energy potential in China and studying its contribution to China's target of cutting CO 2 emissions by 40–45% per unit of GDP by 2020 is crucial for taking countermeasures against climate change and identifying low carbon energy development strategies. This paper presents two scenarios and evaluates the development potential for low carbon energy and its various sources. Based on the evaluation, we analyze how low carbon energy contributes to achieving China's national target of carbon intensity reduction. We draw several conclusions from the analysis. First, low carbon energy will contribute 9.74% (minimum) to 24.42% (maximum) toward the 2020 carbon intensity target under three economic development schemes. Second, the contribution will decrease when the GDP growth rate increases. Third, to maintain the same contribution with high GDP growth rates, China should not only strengthen its investment and policy stimulation for low carbon energy but also simultaneously optimize economic structures and improve carbon productivity. - Highlights: ► Low carbon energy can substitute at least 659.5 Mtce of fossil energy in 2020. ► Potential of hydropower ranks first among all low carbon energy sources in 2020. ► Low carbon energy will contribute at least 9.47% to reach carbon target in 2020. ► China should formulate and implement comprehensive measures to cut carbon emission.

Modelling accidental releases of carbon 14 in the environment: application as an excel spreadsheet

International Nuclear Information System (INIS)

Le Dizes, S.; Tamponnet, C.

2004-01-01

An application as an Excel spreadsheet of the simplified modelling approach of carbon 14 transfer in the environment developed by Tamponnet (2002) is presented. Based on the use of growth models of biological systems (plants, animals, etc.), the one-pool model (organic carbon) that was developed estimates the concentration of carbon 14 within the different compartments of the food chain and in fine the dose to man by ingestion in the case of a chronic or accidental release of carbon 14 in a river or the atmosphere. Data and knowledge have been implemented on Excel using the object-oriented programming language VisualBasic (Microsoft Visual Basic 6.0). The structure of the conceptual model and the Excel sheet are first briefly exposed. A numerical application of the model under a scenario of an accidental release of carbon 14 in the atmosphere is then presented. Simulation results and perspectives are discussed. (author)

Fine-Grained Targets for Laser Synthesis of Carbon Nanotubes

Science.gov (United States)

Smith, Michael W. (Inventor); Park, Cheol (Inventor)

2017-01-01

A mechanically robust, binder-free, inexpensive target for laser synthesis of carbon nanotubes and a method for making same, comprising the steps of mixing prismatic edge natural flake graphite with a metal powder catalyst and pressing the graphite and metal powder mixture into a mold having a desired target shape.

Carbon-14 as an indicator of CO2 pollution in cities

International Nuclear Information System (INIS)

Vogel, J.C.; Uhlitzsch, I.

1975-01-01

The combustion of fossil fuels in cities, and especially in industrial areas, releases large quantities of carbon dioxide into the local atmosphere. This carbon dioxide does not contain carbon-14, with the result that the carbon-14 content of the atmospheric carbon dioxide is locally depleted. The degree of depletion provides a measure for the carbon dioxide pollution at the sampling site. Since growing plants represent a convenient average sample of the carbon dioxide in the air, the leaves of deciduous trees can be used for comparing the magnitude of local pollution in different localities during the summer growing period. A series of leaf samples collected in 1973 from Europe, North America and South Africa reveals the expected differences in the degree of pollution. Extreme instances occur in Scholven (Ruhrgebiet, Germany), where the average day-time carbon dioxide content during the summer months is found to be 8.7% above normal, and in Manhatten, New York City, where the corresponding figure is 6.4%. The technique can easily be extended to include the winter months by directly absorbing carbon dioxide in a hydroxide solution during different seasons. The proposed method is sensitive but much less time-consuming than the continuous measurement of the carbon dioxide concentration in the air. It thus lends itself to the monitoring of impact areas of pollution. (author)

Determination of 14C age of inorganic and organic carbon in ancient Siberian permafrost

Science.gov (United States)

Onstott, T. C.; Liang, R.; Lau, M.; Vishnivetskaya, T. A.; Lloyd, K. G.; Pfiffner, S. M.; Hodgins, G.; Rivkina, E.

2017-12-01

Permafrost represents a large reservoir of ancient carbon that could have an important impact on the global carbon budget during climate warming. Due to the low turnover rate of carbon by microorganisms at subzero temperatures, the persistence of ancient carbon in younger permafrost deposits could also pose challenges for radiocarbon dating of permafrost sediment. We utilized Accelerator Mass Spectrometry to determine the 14C age of inorganic carbon, labile and recalcitrant organic carbon in Siberian permafrost sediment sampled at various depths from 2.9 to 5.6m. The fraction of inorganic carbon (CO2) was collected after acidification using phosphoric acid. The labile (younger) and recalcitrant (old) organic carbon in the subsequent residues were collected after combustion at 400 ºC and 800 ºC, respectively. The percentages of inorganic carbon increased from the youngest (2.9m) to the oldest (5.6m), whereas the fractions for organic carbon varied significantly at different depths. The 14C age determined in the inorganic fraction in the top sample (2.9 m) was 21,760 yr BP and gradually increased to 33,900 yr BP in the relative deeper sediment (3.5 and 5.6 m). Surprisingly, the fraction of "younger" carbon liberated at 400 oC was older than the more recalcitrant and presumably older organic carbon liberated at 800 oC in all cases. Moreover, the 14C age of the younger and older organic carbon fractions did not increase with depth as observed in the carbonate fraction. In particular, the 14C age of the organic carbon in the top sample (38,590-41,700 yr BP) was much older than the deeper samples at depth of 3.5m (18,228-20,158 yr BP) and 5.6m (29,040-38,020 yr BP). It should be noticed that the metabolism of ancient carbon in frozen permafrost may vary at different depths due to the different proportion of necromass and metabolically active microbes. Therefore, additional knowledge about the carbon dynamics of permafrost and more investigation would be required to

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

Immobilization of carbon 14 contained in spent fuel hulls through melting-solidification treatment

International Nuclear Information System (INIS)

Mizuno, T.; Maeda, T.; Nakayama, S.; Banba, T.

2004-01-01

The melting-solidification treatment of spent nuclear fuel hulls is a potential technique to improve immobilization/stabilization of carbon-14 which is mobile in the environment due to its weakly absorbing properties. Carbon-14 can be immobilized in a solid during the treatment under an inert gas atmosphere, where carbon is not oxidized to gaseous form and remains in the solid. A series of laboratory scale experiments on retention of carbon into an alloy waste form was conducted. Metallic zirconium was melted with metallic copper (Zr/Cu=8/2 in weight) at 1200 deg C under an argon atmosphere. Almost all of the carbon remained in the resulting zirconium-copper alloy. (authors)

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)

Study of the biogenesis of flavones and cinnamic acids by using molecules labelled with carbon 14

International Nuclear Information System (INIS)

Chabannes, Bernard

1970-01-01

This research thesis reports the study of flavones, flavonoid compounds and cinnamic acids which are very common as natural pigments in plant species. The author first reports the study of the synthesis of shikimic acid labelled with carbon 14 (biological methods of preparation, synthesis), and then the synthesis of prunin labelled with carbon 14. The next part reports the study of the transformation of prunin labelled with carbon 14 into cosmosiine in flowers with white cosmos. The author finally compares the introduction of cinnamic acid and of shikimic acid (both labelled with carbon 14) into the sinapic acid of red cabbage leaves

Carbon-14 discharges from the nuclear fuel cycle: Pt. 1

International Nuclear Information System (INIS)

McCartney, M.; Baxter, M.S.; Scott, E.M.

1988-01-01

The radiological impact of 14 C produced by the nuclear fuel cycle is assessed using an advanced 25-box model of the carbon cycle coupled with a range of feasible energy-use scenarios. In particular, this study estimates both the short- and long-term dose implications to the global population. In the former context, it is predicted that the atmospheric 14 C specific activity in the year 2050 will be 234 Bq kg -1 (carbon), corresponding to delivery of an individual effective dose equivalent rate of 15 μSv year -1 . The contribution of reactor-derived 14 C to the individual dose rate increases steadily throughout this period, reaching 1.8 μSv year -1 in 2050, well within ICRP limits. In the longer term, however, the collective effective dose equivalent commitment is conservatively estimated at 141 man Sv TBq -1 , corresponding to 480 man Sv (GW(e) year) -1 . These figures indicate that 14 C could generate one of the largest contributions to the total dose to man from nuclear power production. (author)

Synthesis of pyrimidinic nucleotides and nucleosides labelled with carbon 14, through tri-methylsilylated and lithiated derivatives

International Nuclear Information System (INIS)

Godbillon, Jacques

1972-01-01

After a presentation of the trimethysilylation, lithiation, and methylation processes, this research thesis reports the synthesis of methyl carbon 14 - 5 - uridine, of ethyl carbon 14 - 5 - desoxy - 2' - uridine, and of thymidine monophosphate - 5' (methyl carbon 14) by using silylated and lithiated derivatives. The author also reports preliminary studies of biological studies of the trimethylsilyl-5-uridine and of the iodine-6-thymine

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.

Uranium targets sandwiched between carbon layers for use on target wheels and on a Wobbler in heavy-ion bombardments

International Nuclear Information System (INIS)

Folger, H.; Hartmann, W.; Klemm, J.; Thalheimer, W.

1989-01-01

Uranium layers of ≅ 0.4 mg/cm 2 are evaporated by means of a 6 kW electron-beam gun onto 0.04 mg/cm 2 thick carbon films in a high-vacuum process; a protecting layer of ≅ 0.01 mg/cm 2 of carbon is added in the same vacuum cycle. The evaporation- and deposition yields are discussed and measurements of target characteristics are described. C/U/C sandwich targets in the shape of a sector of an annulus are prepared for use on rotating target wheels of 155 mm radius to be bombarded with a pulsed beam of heavy ions. One type of circular targets of 20 mm in diameter is mounted to a target wobbler. Both, wheel and wobbler, distribute the intensity of the heavy-ion beam to a larger area to reduce radiation damages. Examples of target applications will be mentioned. (orig.)

Land-Based Mitigation Strategies under the Mid-Term Carbon Reduction Targets in Indonesia

Directory of Open Access Journals (Sweden)

Tomoko Hasegawa

2016-12-01

Full Text Available We investigated the key mitigation options for achieving the mid-term target for carbon emission reduction in Indonesia. A computable general equilibrium model coupled with a land-based mitigation technology model was used to evaluate specific mitigation options within the whole economic framework. The results revealed three primary findings: (1 If no climate policy were implemented, Indonesia’s total greenhouse gas emissions would reach 3.0 GtCO2eq by 2030; (2 To reduce carbon emissions to meet the latest Intended Nationally-Determined Contributions (INDC target, ~58% of total reductions should come from the agriculture, forestry and other land use sectors by implementing forest protection, afforestation and plantation efforts; (3 A higher carbon price in 2020 suggests that meeting the 2020 target would be economically challenging, whereas the INDC target for 2030 would be more economically realistic in Indonesia.

Restoring degraded land: contributing to Aichi Targets 14, 15, and beyond

DEFF Research Database (Denmark)

Navarro, Laetitia M.; Marques, Alexandra; Ceausu, Silvia

2018-01-01

Restoration ecology is gaining momentum on the international conservation scene. In particular, restoring degraded ecosystems is central to Aichi Biodiversity Targets 14 and 15 set by the Convention on Biological Diversity. Depending on the definition of degradation, from 2 to 47% of the global...... for restoration. Finally, we assess national conservation targets to examine the potential multifaceted impacts of achieving Aichi Targets 14 and 15 on biodiversity and society....... land surface could require restoration. Here, we review the range of goals and approaches to restoration, from active interventions to more passive approaches such as rewilding. We identify biodiversity offsets, payments for ecosystem services and agri-enviromental schemes as enabling policy mechanisms...

The 14 mu m band of carbon stars

NARCIS (Netherlands)

Yamamura, [No Value; de Jong, T; Waters, LBFM; Cami, J; Justtanont, K; LeBertre, T; Lebre, A; Waelkens, C

1999-01-01

We have studied the absorption bands around 14 mum in the spectra of 11 carbon stars with mass-loss rates ranging from 10(-8) to 10(-4) M-circle dot yr(-1), based on data obtained with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). All stars clearly show a

Synthesis of 1-(4-methylsulfone-phenyl)-5-(4-fluoro-phenyl)-5-[14C]-1,2,3- triazole and 1-(4-sulfonamide-phenyl)-5-(4-fluoro-phenyl)-5-[14C]-1,2,3- triazole as novel carbon-14 anticonvulsant

International Nuclear Information System (INIS)

Saemian, N.; Shirvani, G.; Matloubi, H.

2006-01-01

Two 1,2,3-triazole anticonvulsants, 1-(4-methylsulfone-phenyl)-5-(4-fluoro-phenyl)-5-[ 14 C]-1,2,3-triazole and 1-(4-sulfonamide-phenyl)-5-(4- fluoro-phenyl)-5-[ 14 C]-1,2,3-triazole, both labeled with carbon-14 in the 5-position were prepared from para-fluoro-benzonitrile-[cyano- 14 C]. (author)

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)

The management of carbon-14 in Canadian nuclear facilities

International Nuclear Information System (INIS)

1995-07-01

In Canada, Derived Emission Limits (DELs) for the release of radionuclides from nuclear facilities are set to ensure that the dose to a member of a critical group from one year's release does not exceed the limit on annual dose to a member of the public set by the Atomic Energy Control Regulations. The Advisory Committee on Radiological Protection (ACRP) has expressed concerns as to whether this procedure provides adequate protection to members of the public, including future generations, for certain radionuclides such as a carbon-14 ( 14 C), which can accumulate in the environment and which can be dispersed, through environmental processes, beyond the local region where the critical group is assumed to live. The ACRP subsequently established a Working Group to review the production, release, environmental levels, and waste management of 14 C arising in CANDU power reactors. The ACRP recommendations resulting from this review can be summarized as · Given the current levels of emissions from CANDU nuclear power stations resulting from the use of a carbon dioxide annulus gas and the limitations in the calculation and use of collective dose, the ACRP sees no need for and additional collective dose limit to be applied to these sources. · The AECB should require licensees of power reactors and waste management sites to provide an annual inventory of 14 C held within reactor buildings and waste management sites; to provide information on the stability of the ion exchange resins and their continuing ability to retain the 14 C; to demonstrate on an ongoing basis that releases of 14 C are maintained at a small fraction of the emission limits; and to report annually the critical group and local collective doses arising from releases of 14 C. 61 refs., 25 tabs., 4 figs

Estimating the Contribution of Industry Structure Adjustment to the Carbon Intensity Target: A Case of Guangdong

Directory of Open Access Journals (Sweden)

Ping Wang

2016-04-01

Full Text Available Industry structure adjustment is an effective measure to achieve the carbon intensity target of Guangdong Province. Accurately evaluating the contribution of industry structure adjustment to the carbon intensity target is helpful for the government to implement more flexible and effective policies and measures for CO2 emissions reduction. In this paper, we attempt to evaluate the contribution of industry structure adjustment to the carbon intensity target. Firstly, we predict the gross domestic product (GDP with scenario forecasting, industry structure with the Markov chain model, CO2 emissions with a novel correlation mode based on least squares support vector machine, and then we assess the contribution of industry structure adjustment to the carbon intensity target of Guangdong during the period of 2011–2015 under nine scenarios. The obtained results show, in the ideal scenario, that the economy will grow at a high speed and the industry structure will be significantly adjusted, and thus the carbon intensity in 2015 will decrease by 25.53% compared to that in 2010, which will make a 130.94% contribution to the carbon intensity target. Meanwhile, in the conservative scenario, the economy will grow at a low speed and the industry structure will be slightly adjusted, and thus the carbon intensity in 2015 will decrease by 23.89% compared to that in 2010, which will make a 122.50% contribution to the carbon intensity target.

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

International Nuclear Information System (INIS)

Yang, W.; Sheng, C.; Voroney, P.

2005-01-01

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

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

International Nuclear Information System (INIS)

Kinnison, D.E.; Wuebbles, D.J.; Johnston, H.S.

1992-02-01

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 K zz and K yy 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 K yy 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

Accelerator mass analyses of meteorites - carbon-14 terrestrial ages

International Nuclear Information System (INIS)

Miura, Y.; Rucklidge, J.; Beukens, R.; Fireman, E.

1988-01-01

Carbon-14 terrestrial ages of ten Antarctic meteorites have been measured by the IsoTrace accelerator mass spectrometry (AMS). The 14 C terrestrial age of 1 gram sample was determined from 14 C concentrations collected at melt and re-melt temperatures, compared with the 14 C concentration of the known Bruderheim chondrite. Yamato-790448 (LL3) chondrite was found to be the oldest terrestrial age of 3x10 4 years in the nine Yamato chondrites, whereas Yamato-791630 (L4) chondrite is considered to be the youngest chondrites less than thousand years. Allan Hills chondrite of ALH-77231 (L6) shows older terrestrial age than the nine Yamato chondrites. New accelerator data of the terrestrial age show higher accuracy with smaller sample than the previous counting method. (author)

Laboratory Experiments to Evaluate Diffusion of 14C into Nevada Test Site Carbonate Aquifer Matrix

Energy Technology Data Exchange (ETDEWEB)

Ronald L. Hershey; William Howcroft; Paul W. Reimus

2003-03-01

Determination of groundwater flow velocities at the Nevada Test Site is important since groundwater is the principal transport medium of underground radionuclides. However, 14C-based groundwater velocities in the carbonate aquifers of the Nevada Test Site are several orders of magnitude slower than velocities derived from the Underground Test Area regional numerical model. This discrepancy has been attributed to the loss or retardation of 14C from groundwater into the surrounding aquifer matrix making 14C-based groundwater ages appear much older. Laboratory experiments were used to investigate the retardation of 14C in the carbonate aquifers at the Nevada Test Site. Three sets of experiments were conducted evaluating the diffusion of 14C into the carbonate aquifer matrix, adsorption and/or isotopic exchange onto the pore surfaces of the carbonate matrix, and adsorption and/or isotopic exchange onto the fracture surfaces of the carbonate aquifer. Experimental results a nd published aquifer matrix and fracture porosities from the Lower Carbonate Aquifer were applied to a 14C retardation model. The model produced an extremely wide range of retardation factors because of the wide range of published aquifer matrix and fracture porosities (over three orders of magnitude). Large retardation factors suggest that groundwater with very little measured 14C activity may actually be very young if matrix porosity is large relative to the fracture porosity. Groundwater samples collected from highly fractured aquifers with large effective fracture porosities may have relatively small correction factors, while samples from aquifers with a few widely spaced fractures may have very large correction factors. These retardation factors were then used to calculate groundwater velocities from a proposed flow path at the Nevada Test Site. The upper end of the range of 14C correction factors estimated groundwater velocities that appear to be at least an order of magnitude too high compared

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)

Koo, Choongwan; Kim, Hyunjoong; Hong, Taehoon

2014-01-01

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 CO 2 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

Metabolism and risks from tritium and carbon-14 in the developing organism

International Nuclear Information System (INIS)

Gerber, G.B.; Kirchmann, R.; Hoek, J. van den

1987-01-01

In this review the risks are considered from tritium and carbon-14 to the developing organs of mammals. It mainly deals with H-3 but the conclusions are largely valid also for C-14. The metabolism and average tissue of THO as well as of organically bound tritium are discussed. Dosimetry of radiosensitive structures is also considered. 14 refs.; 2 figs.; 1 table

Physiological conditions and uptake of inorganic carbon-14 by plant roots

International Nuclear Information System (INIS)

Amiro, B.D.; Ewing, L.L.

1992-01-01

The uptake of inorganic 14 C by bean plant roots was measured. The plants were grown in a nutrient solution culture at pH 6 and a NaH 14 CO 3 tracer was added to the growth medium. Photosynthesis and transpiration were varied by exposing the aerial portions of the plants to different atmospheric CO 2 concentrations, humidities and light levels in a cuvette system. Leaf concentrations of 14 C were measured at the end of the experiments using liquid scintillation counting. Plant uptake of 14 C via the roots was independent of the photosynthetic rate and, in most cases, could be predicted by knowing the transpiration rate and the nutrient solution concentration. However, when a less efficient root-medium aeration system was used, 14 C uptake was greater than that predicted using transpiration, a phenomenon observed by other researchers. This contrasted to results of another experiment where the measured uptake of iodine was much slower than that predicted using transpiration. Knowledge of transpiration rates is useful in predicting inorganic carbon uptake via the roots and in estimating 14 C transport from contaminated soils to biota. Also, the independence of the uptake from photosynthesis and ambient CO 2 concentrations suggests that future increases in atmospheric CO 2 concentrations may not have a direct effect on root uptake of soil carbon. (author)

The use of barytocalcite for carbon 14 immobilization: One-year leaching behavior

Energy Technology Data Exchange (ETDEWEB)

Massoni, Nicolas, E-mail: nicolas.massoni@cea.fr; Marcou, Céline; Rosen, Jérémy; Jollivet, Patrick

2014-11-15

The spent nuclear fuel reprocessing process is one of the anthropogenic sources of carbon-14, and since this element is highly mobile in the geosphere, its sequestration is necessary. Several phases and industrial solutions to immobilize this radionuclide have been studied, including the barytocalcite phase BaCa(CO{sub 3}){sub 2} at 8.08 wt.% of C, which has many advantages such as its low specific volume of carbon. Recently, different options to synthesize this phase have been reported. Here we report on the aqueous durability of barytocalcite, studied for one year with pure water at 30 °C, in order to complete the behavior studies. Unexpected leaching behavior was encountered: it had been supposed that barytocalcite would only leach slowly, but after 1 year, it was no longer present. It appears that its simple CaCO{sub 3} and BaCO{sub 3} constituents precipitated, though the overall carbon loss was low during the period studied. This research gives a new insight into the behavior of this phase regarding carbon-14 immobilization.

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.

Rapid localization of carbon 14-labeled molecules in biological samples by ion mass microscopy

International Nuclear Information System (INIS)

Hindie, E.; Escaig, F.; Coulomb, B.; Lebreton, C.; Galle, P.

1989-01-01

We report here on the ability of secondary ion mass spectrometry (SIMS) to provide rapid imaging of the intracellular distribution of 14 C-labeled molecules. The validity of this method, using mass discrimination of carbon 14 atoms, was assessed by imaging the distribution of two molecules of well-known metabolism, [ 14 C]-thymidine and [ 14 C]-uridine, incorporated by human fibroblasts in culture. As expected, 14 C ion images showed the presence of [ 14 C]-thymidine in the nucleus of dividing cells, whereas [ 14 C]-uridine was present in the cytoplasm as well as the nucleus of all cells, with a large concentration in the nucleoli. The time required to obtain the distribution images with the SMI 300 microscope was less than 6 min, whereas microautoradiography, the classical method for mapping the tissue distribution of 14 C-labeled molecules, usually requires exposure times of several months. Secondary ion mass spectrometry using in situ mass discrimination is proposed here as a very sensitive method which permits rapid imaging of the subcellular distribution of molecules labeled with carbon 14

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)

Synthesis of a polycyclic aromatic hydrocarbon marked with carbon-14: (b, d e f) dibenzo-chrysene 14C-7,14

International Nuclear Information System (INIS)

Chatelain, G.

1965-01-01

(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) [fr

The Edison lamp: O-15 carbon monoxide production in the target

International Nuclear Information System (INIS)

Votaw, J.R.; Satter, M.R.; Sunderland, J.J.; Martin, C.C.; Nickles, R.J.

1986-01-01

A target has been developed for the on line production of C 15 O in order to maximize the available activity for PET studies. The target features an internal carbon filament which is heated to perform the conversion from 15 O-O 2 to either C 15 O or C 15 O 2 . After the initial success of a bare carbon filament, the experiment was repeated using a platinum plated filament in the hope that the platinum would act as a catalyst allowing the conversion reaction to C 15 O to take place at reduced temperatures. Results indicate that the Pt did not alter the conversion, but did greatly increase the temperature to which the filament could be heated and it also increased the filament lifetime. (author)

Metabolism of carbon-14 labelled l-tryptophan, l-kynerenine and hydroxy-l-kynerenine in miners with scleroderma

International Nuclear Information System (INIS)

Hankes, L.V.; De Bruin, E.; Jansen, C.R.; Voster, L.; Schmaeler, M.

1977-01-01

Six South African white miners were studied with the 2-g l-tryptophan load test and tracer doses of L-tryptophan-7a-carbon-14, L-kynurenine-keto-carbon-14 and hydroxy-L-kynerenine-keto-carbon-14. The breath 14 CO 2 and 14 urinary metabolites were measured. When they were compared with a previous study of American women with scleroderma, similar 14 CO 2 and tryptophan metabolite excretion patterns were observed in the data from the miners. The labelled quinolinic acid excretion was more significantly elevated in the South African miners' urine than in the urine of the American women. The data from both studies suggest that some patients with scleroderma have an altered step in the tryptophan metabolic pathway after hydroxy-anthranilic acid. What relationship exists between the induction of pulmonary silicosis and the subsequent development of scleroderma, requires additional human studies

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)

Carbon-14 behavior in a cement-dominated environment: Implications for spent CANDU resin waste disposal

International Nuclear Information System (INIS)

Dayal, R.; Reardon, E.J.

1994-01-01

Cement based waste forms and concrete engineered barriers are expected to play a key role in providing 14 C waste containment and control 14 C migration for time periods commensurate with its hazardous life of about 50,000 years. The main thrust of this study was, therefore, to evaluate the performance of cement based waste forms with regard to 14 C containment. Of particular importance are the geochemical processes controlling 14 C solubility and release under anticipated cement dominated low and intermediate level waste repository conditions. Immobilization of carbonate-form exchange resin in grout involves transfer of sorbed 14 CO 3 2- ions, through exchange for hydroxyl ions from the grout slurry, followed by localized precipitation of solid calcium carbonate at the cement/resin interface in the grout matrix. Carbon-14 release behavior can be attributed to the dissolution characteristics and solubility of calcite present in the cement based waste form. The groundwater flow regime can exert a pronounced effect both on the near-field chemistry and the leaching behavior of 14 C. For a cement dominated repository, at relatively low-flow or stagnant groundwater conditions, the alkaline near-field chemical environments inhibits the release of 14 C from the cemented waste form. Under high flow conditions, the near-field environment is characterized by relatively neutral pH conditions which promote calcite dissolution, thus resulting in 14 C release from the waste form

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.

Carbon 14 distribution in irradiated BWR fuel cladding and released carbon 14 after aqueous immersion of 6.5 years

Energy Technology Data Exchange (ETDEWEB)

Sakuragi, T. [Radioactive Waste Management Funding and Research Center, Tsukishima 1-15-7, Chuo City, Tokyo, 104-0052 (Japan); Yamashita, Y.; Akagi, M.; Takahashi, R. [TOSHIBA Corporation, Ukishima Cho 4-1, Kawasaki Ward, Kawasaki, 210-0862 (Japan)

2016-07-01

Spent fuel cladding which is highly activated and strongly contaminated is expected to be disposed of in an underground repository. A typical activation product in the activated metal waste is carbon 14 ({sup 14}C), which is mainly generated by the {sup 14}N(n,p){sup 14}C reaction and produces a significant exposure dose due to the large inventory, long half-life (5730 years), rapid release rate, and the speciation and consequent migration parameters. In the preliminary Japanese safety case, the release of radionuclides from the metal matrix is regarded as the corrosion-related congruent release, and the cladding oxide layer is regarded as a source of instant release fraction (IRF). In the present work, specific activity of {sup 14}C was measured using an irradiated BWR fuel cladding (Zircaloy-2, average rod burnup of 41.6 GWd/tU) which has an external oxide film having a thickness of 25.3 μm. The {sup 14}C specific activity of the base metal was 1.49*10{sup 4} Bq/g, which in the corresponding burnup is comparable to values in the existing literature, which were obtained from various irradiated claddings. Although the specific activity in oxide was 2.8 times the base metal activity due to the additive generation by the {sup 17}O(n,α){sup 14}C reaction, the {sup 14}C abundance in oxide was less than 10% of total inventory. A static leaching test using the cladding tube was carried out in an air-tight vessel filled with a deoxygenated dilute NaOH solution (pH of 12.5) at room temperature. After 6.5 years, {sup 14}C was found in each leachate fraction of gas phase and dissolved organics and inorganics, the total of which was less than 0.01% of the {sup 14}C inventory of the immersed cladding tube. A simple calculation based on the congruent release with Zircaloy corrosion has suggested that the 96.7% of released {sup 14}C was from the external oxide layer and 3.3% was from the base Zircaloy metal. However, both the {sup 14}C abundance and the low leaching rate

Fate of gaseous tritium and carbon-14 released from buried low-level radioactive waste

International Nuclear Information System (INIS)

Striegl, R.G.

1988-01-01

Microbial decomposition, chemical degradation, and volatilization of buried low-level radioactive waste results in the release of gases containing tritium ( 3 H) and carbon-14 ( 14 C) to the surrounding environment. Water vapor, carbon dioxide, and methane that contain 3 H or 14 C are primary products of microbial decomposition of the waste. Depending on the composition of the waste source, chemical degradation and volatilization of waste also may result in the production of a variety of radioactive gases and organic vapors. Movement of the gases in materials that surround waste trenches is affected by physical, geochemical, and biological mechanisms including sorption, gas-water-mineral reactions, isotopic dilution, microbial consumption, and bioaccumulation. These mechanisms either may transfer 3 H and 14 C to solids and infiltrating water or may result in the accumulation of the radionuclides in plant or animal tissue. Gaseous 3 H or 14 C that is not transferred to other forms is ultimately released to the atmosphere

Revision of Fontes & Garnier's model for the initial 14C content of dissolved inorganic carbon used in groundwater dating

Science.gov (United States)

Han, Liang-Feng; Plummer, Niel

2013-01-01

The widely applied model for groundwater dating using 14C proposed by Fontes and Garnier (F&G) (Fontes and Garnier, 1979) estimates the initial 14C content in waters from carbonate-rock aquifers affected by isotopic exchange. Usually, the model of F&G is applied in one of two ways: (1) using a single 13C fractionation factor of gaseous CO2 with respect to a solid carbonate mineral, εg/s, regardless of whether the carbon isotopic exchange is controlled by soil CO2 in the unsaturated zone, or by solid carbonate mineral in the saturated zone; or (2) using different fractionation factors if the exchange process is dominated by soil CO2 gas as opposed to solid carbonate mineral (typically calcite). An analysis of the F&G model shows an inadequate conceptualization, resulting in underestimation of the initial 14C values (14C0) for groundwater systems that have undergone isotopic exchange. The degree to which the 14C0 is underestimated increases with the extent of isotopic exchange. Examples show that in extreme cases, the error in calculated adjusted initial 14C values can be more than 20% modern carbon (pmc). A model is derived that revises the mass balance method of F&G by using a modified model conceptualization. The derivation yields a “global” model both for carbon isotopic exchange dominated by gaseous CO2 in the unsaturated zone, and for carbon isotopic exchange dominated by solid carbonate mineral in the saturated zone. However, the revised model requires different parameters for exchange dominated by gaseous CO2 as opposed to exchange dominated by solid carbonate minerals. The revised model for exchange dominated by gaseous CO2 is shown to be identical to the model of Mook (Mook, 1976). For groundwater systems where exchange occurs both in the unsaturated zone and saturated zone, the revised model can still be used; however, 14C0 will be slightly underestimated. Finally, in carbonate systems undergoing complex geochemical reactions, such as oxidation of

Study of the C-14-contamination potential of C-impurities in CuO and Fe

NARCIS (Netherlands)

Vandeputte, K; Moens, L; Dams, R; van der Plicht, Johannes

1998-01-01

The carbon concentration in CuO and iron was determined by isolating C. The values were in agreement with results reported in other studies. Contaminating carbon from CuO and Fe was transformed to AMS targets and measured for C-14. C-traces in CuO were shown to be the major contribution to the C-14

Acceleration of 14C beams in electrostatic accelerators

International Nuclear Information System (INIS)

Rowton, L.J.; Tesmer, J.R.

1981-01-01

Operational problems in the production and acceleration of 14 C beams for nuclear structure research in Los Alamos National Laboratory's Van de Graaff accelerators are discussed. Methods for the control of contamination in ion sources, accelerators and personnel are described. Sputter source target fabrication techniques and the relative beam production efficiencies of various types of bound particulate carbon sputter source targets are presented

Measurement of the carbon 14 activity at natural level in air samples

International Nuclear Information System (INIS)

Olivier, A.; Tenailleau, L.; Baron, Y.; Maro, D.

2004-01-01

The aim of the study was to measure the carbon 14 activity at natural level in air samples using classical methods of radiochemistry and beta counting. Three different methods have been tested in order to minimise the detection limit. In the three methods, the first step consists in trapping the atmospheric carbon 14 into NaOH (1N) using a bubbling chamber. The atmospheric carbon dioxide reacts with NaOH to form Na 2 CO 3 . In the first method the Na 2 CO 3 solution is mixed with a liquid scintillate and is directly analysed by liquid scintillation counting (LSC). The detection limit is approximately 1 Bq/m 3 of air samples. The second method consists in evaporating the carbonate solution and then counting the solid residue with a proportional gas circulation counter. The detection limit obtained is lower than the first method (0.4 Bq/m 3 of air samples). In the third method, Na 2 CO 3 is precipitated into CaCO 3 in presence of CaCl 2 . CaCO 3 is then analysed by LSC. This method appear to be the most appropriate, the detection limit is 0.05 Bq/m 3 of air samples. (author)

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.; van Dongen, Bart E.; Semiletov, Igor P.; Dudarev, Oleg V.; Yunker, Mark B.; Macdonald, Robie W.; Wacker, Lukas; Montluçon, Daniel B.; Eglinton, Timothy I.

2015-11-01

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.

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

International Nuclear Information System (INIS)

Jayasekara, K.S.; Jayaswkara, K.S.; Bowen, G.D.

2000-01-01

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

Coal chemistry. 8. Reactions of tetralin with coal and with some carbon-14-containing model compounds

International Nuclear Information System (INIS)

Collins, C.J.; Raaen, V.F.; Benjamin, B.M.; Maupin, P.H.; Roark, W.H.

1979-01-01

When coal was treated with tetralin-l- 14 C at 400 0 C, small yields of α- and β-methylnaphthalenes- 14 C were observed. In order to determine the mechanism of the reaction, tetralin was heated with 14 C-labeled 1,3-diphenylpropanes (1), with 1,3-diphenylpropene (2), and with 14 C-labeled phenetoles (3). In each case methylnaphthalenes were observed, and the origins of the methyl groups were determined with carbon-14. In addition to the methylnaphthalenes, 1 and 2 also yielded toluene and ethylbenzene (after 19 h), whereas phenetole-β- 14 C (3-β- 14 C) yielded toluene (unlabeled) plus ethyl- 14 C-benzene, benzene, phenol, and a mixture of α- and β-ethyl- 14 C-naphthalenes. Crossover experiments with labeled phenetole and unlabeled ethyl p-tolyl ether proved the intramolecularity of the reaction phenetole → toluene + ethylbenzene, thus illustrating a 1,2-phenyl shift from oxygen to carbon

Biogenic Carbon Fraction of Biogas and Natural Gas Fuel Mixtures Determined with 14C

NARCIS (Netherlands)

Palstra, Sanne W. L.; Meijer, Harro A. J.

2014-01-01

This study investigates the accuracy of the radiocarbon-based calculation of the biogenic carbon fraction for different biogas and biofossil gas mixtures. The focus is on the uncertainty in the C-14 reference values for 100% biogenic carbon and on the C-13-based isotope fractionation correction of

Achieving CO2 reductions in Colombia: Effects of carbon taxes and abatement targets

International Nuclear Information System (INIS)

Calderón, Silvia; Alvarez, Andrés Camilo; Loboguerrero, Ana María; Arango, Santiago; Calvin, Katherine; Kober, Tom; Daenzer, Kathryn; Fisher-Vanden, Karen

2016-01-01

In this paper we investigate CO 2 emission scenarios for Colombia and the effects of implementing carbon taxes and abatement targets on the energy system. By comparing baseline and policy scenario results from two integrated assessment partial equilibrium models TIAM-ECN and GCAM and two general equilibrium models Phoenix and MEG4C, we provide an indication of future developments and dynamics in the Colombian energy system. Currently, the carbon intensity of the energy system in Colombia is low compared to other countries in Latin America. However, this trend may change given the projected rapid growth of the economy and the potential increase in the use of carbon-based technologies. Climate policy in Colombia is under development and has yet to consider economic instruments such as taxes and abatement targets. This paper shows how taxes or abatement targets can achieve significant CO 2 reductions in Colombia. Though abatement may be achieved through different pathways, taxes and targets promote the entry of cleaner energy sources into the market and reduce final energy demand through energy efficiency improvements and other demand-side responses. The electric power sector plays an important role in achieving CO 2 emission reductions in Colombia, through the increase of hydropower, the introduction of wind technologies, and the deployment of biomass, coal and natural gas with CO 2 capture and storage (CCS). Uncertainty over the prevailing mitigation pathway reinforces the importance of climate policy to guide sectors toward low-carbon technologies. This paper also assesses the economy-wide implications of mitigation policies such as potential losses in GDP and consumption. An assessment of the legal, institutional, social and environmental barriers to economy-wide mitigation policies is critical yet beyond the scope of this paper. - Highlights: • Four energy and economy-wide models under carbon mitigation scenarios are compared. • Baseline results show that CO

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

International Nuclear Information System (INIS)

Nishizawa, Kunihide; Nagatsu, Toshiharu; Togari, Akifumi; Matsumoto, Shosei

1991-01-01

The atmospheric testing of nuclear weapons since 1945 caused a significant increase in the concentration of atmospheric 14 C. The 14 C concentration in plants that assimilate 14 C directly by photosynthesis reflects the atmospheric 14 C 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 14 C concentration which reflects the 14 C concentration in the blood at the time collagen metabolism ceased. The distribution of the 14 C 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 14 C concentration in teeth

The synthesis of a tritium, carbon-14, and stable isotope-labeled cathepsin C inhibitors.

Science.gov (United States)

Allen, Paul; Bragg, Ryan A; Caffrey, Moya; Ericsson, Cecilia; Hickey, Michael J; Kingston, Lee P; Elmore, Charles S

2017-02-01

As part of a medicinal chemistry program aimed at developing a highly potent and selective cathepsin C inhibitor, tritium, carbon-14, and stable isotope-labeled materials were required. The synthesis of tritium-labeled methanesulfonate 5 was achieved via catalytic tritiolysis of a chloro precursor, albeit at a low radiochemical purity of 67%. Tritium-labeled AZD5248 was prepared via a 3-stage synthesis, utilizing amide-directed hydrogen isotope exchange. Carbon-14 and stable isotope-labeled AZD5248 were successfully prepared through modifications of the medicinal chemistry synthetic route, enabling the use of available labeled intermediates. Copyright © 2016 John Wiley & Sons, Ltd.

Application of the dose limitation system to the control of carbon-14 releases from heavy-water-moderated reactors

International Nuclear Information System (INIS)

Beninson, D.; Gonzalez, A.J.

1982-01-01

Heavy-water-moderated reactors produce substantially more carbon-14 than light-water reactors. Applying the principles of the systems of dose limitation, the paper presents the rationale used for establishing the release limit for effluents containing this nuclide and for the decisions made regarding the effluent treatment in the third nuclear power station in Argentina. Production of carbon-14 in PHWR and the release routes are analysed in the light of the different effluent treatment possibilities. An optimization assessment is presented, taking into account effluent treatment and waste management costs, and the collective effective dose commitment due to the releases. The contribution of present carbon-14 releases to future individual doses is also analysed in the light of an upper bound for the contribution, representing a fraction of the individual dose limits. The paper presents the resulting requirements for the effluent treatment regarding carbon-14 and the corresponding regulatory aspects used in Argentina. (author)

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

KAUST Repository

Serag, Maged F.; Kaji, Noritada; Habuchi, Satoshi; Bianco, Alberto; Baba, Yoshinobu

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.

Carbon-14 dynamics in rice: an extension of the ORYZA2000 model

Energy Technology Data Exchange (ETDEWEB)

Galeriu, D.; Melintescu, A. [' ' Horia Hulubei' ' National Institute for Physics and Nuclear Engineering, Life and Environmental Physics Department, 30 Reactorului St., POB MG-6, Bucharest-Magurele (Romania)

2014-03-15

Carbon-14 ({sup 14}C) is a radionuclide of major interest in nuclear power production. The Fukushima accident changed the public attitude on the use of nuclear energy all over the world. In terms of nuclear safety, the need of quality-assured radiological models was emphasized by many international organizations, and for models used by decision-makers (i.e. regulatory environmental models and radiological models), a moderate conservatism, transparency, relative simplicity and user friendliness are required. Because the interaction between crops and the environment is complex and regulated by many feedback mechanisms, however, these requirements are difficult to accomplish. The present study makes a step forward regarding the development of a robust model dealing with food contamination after a short-term accidental emission and considers a single crop species, rice (Oryza sativa), one of the most widely used rice species. Old and more recent experimental data regarding the carbon dynamics in rice plants are reviewed, and a well-established crop growth model, ORYZA2000, is used and adapted in order to assess the dynamics of {sup 14}C in rice after a short-term exposure to {sup 14}CO{sub 2}. Here, the model is used to investigate the role of the genotype, management and weather on the concentration of radiocarbon at harvest. (orig.)

Study on hydrogen transfer in coal liquefaction by tritium and carbon-14 tracers

International Nuclear Information System (INIS)

Nitoh, Osamu; Kabe, Toshiaki; Kabe, Yaeko.

1985-01-01

For the analysis of mechanism of hydrogenation and cracking of coal, the liquefaction of Taiheiyo coal using tritium labeled gaseous hydrogen and tritium labeled tetralin with small amounts of carbon-14 labeled naphthalene has been studied. Taiheiyo coal(25g) was thermally decomposed in tetralin or naphthalene solvent(75g) at 400--440 0 C under the initial hydrogen pressure of 5.9MPa for 30min with Ni-Mo-Al 2 O 3 catalyst(0--5g). The reaction mixture in an autoclave was separated by filtration, distillation and solvent extraction. Produced gas, oils and the solvent were analyzed by gas chromatography. The tritium and carbon-14 contents of separated reaction products were measured with a liquid scintilation counter to study the hydrogen transfer mechanism. The distribution of reaction products and the amount of hydrogen transfer from gas or solvent to the products were also determined. In hydrogen donor solvent such as tetralin, the coal liquefaction yield was independent from the catalyst, but the catalyst was effective in hydrocracking of preasphaltene and asphaltene. In naphthalene solvent, the coal liquefaction reaction hardly occured in the absence of the catalyst, because hydrogen transfer from both the solvent and gaseous hydrogen was scarce. Tritium distribution in the reaction products showed that complicated hydrogen exchange reactions between gaseous hydrogen, coal liquids and solvent came out by the presence of coal liquids and catalyst. The very small amounts of carbon-14 transferred to the liquefaction products showed that carbon exchange or transfer between solvent and coal did not take place. (author)

Minimizing the non-specific binding of nanoparticles to the brain enables active targeting of Fn14-positive glioblastoma cells.

Science.gov (United States)

Schneider, Craig S; Perez, Jimena G; Cheng, Emily; Zhang, Clark; Mastorakos, Panagiotis; Hanes, Justin; Winkles, Jeffrey A; Woodworth, Graeme F; Kim, Anthony J

2015-02-01

A major limitation in the treatment of glioblastoma (GBM), the most common and deadly primary brain cancer, is delivery of therapeutics to invading tumor cells outside of the area that is safe for surgical removal. A promising way to target invading GBM cells is via drug-loaded nanoparticles that bind to fibroblast growth factor-inducible 14 (Fn14), thereby potentially improving efficacy and reducing toxicity. However, achieving broad particle distribution and nanoparticle targeting within the brain remains a significant challenge due to the adhesive extracellular matrix (ECM) and clearance mechanisms in the brain. In this work, we developed Fn14 monoclonal antibody-decorated nanoparticles that can efficiently penetrate brain tissue. We show these Fn14-targeted brain tissue penetrating nanoparticles are able to (i) selectively bind to recombinant Fn14 but not brain ECM proteins, (ii) associate with and be internalized by Fn14-positive GBM cells, and (iii) diffuse within brain tissue in a manner similar to non-targeted brain penetrating nanoparticles. In addition, when administered intracranially, Fn14-targeted nanoparticles showed improved tumor cell co-localization in mice bearing human GBM xenografts compared to non-targeted nanoparticles. Minimizing non-specific binding of targeted nanoparticles in the brain may greatly improve the access of particulate delivery systems to remote brain tumor cells and other brain targets. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis of puric bases labelled with carbon 14 and nitrogen 15

International Nuclear Information System (INIS)

Lamorre, Yves

1975-01-01

In this report for graduation in organic chemistry engineering, the author reports the synthesis of adenine 14 C-2 et 14 C-6 by two different chemical ways from two derivatives of imidazole. He has used adenine 14 C-6 to obtain hypoxanthine 14 C-6, and then, by enzymatic processing, uric acid 14 C-6. He reports the study of the production of guanine 14 C-2 by cyclization of silylated derivative of imidazole with the carbon 14 C sulphur. However, a method of complete synthesis of this same compound revealed to be more practical. This complete synthesis way allowed the labelling of guanine in positions 1, 2 and 3 by the 96 per cent isotopic nitrogen. Nitrogen in positions 7 and 9 could have been labelled by the same way from the ethyl cyanoacetate 15 N and from the sodium nitrite 15 N. The study of the mass spectrum of these compounds labelled with nitrogen 15 N allowed most of fragments obtained during this analysis to be identified [fr

CO2-laser decomposition method of carbonate for AMS 14C measurements

International Nuclear Information System (INIS)

Kitagawa, Hiroyuki

2013-01-01

A CO 2 laser decomposition method enabled the efficient preparation of carbonate samples for AMS 14 C measurement. Samples were loaded in a vacuum chamber and thermally decomposed using laser emission. CO 2 liberated from the carbonate was directly trapped in the cold finger trap of a small CO 2 reduction reactor and graphitized by a hydrogen gas reduction method using catalytic iron powder. The fraction modern values for 0.07–0.57 mg of carbon, obtained from 200 μm-diameter spots of IAEA-C1, varied with sample size in the range of 0.00072 ± 0.00003 to 0.00615 ± 0.00052. The contamination induced by the laser decomposition method and the following graphite handling was estimated to be 0.53 ± 0.21 μg of modern carbon, assuming a constant amount of extraneous carbon contamination. This method could also make it possible to avoid the time-consuming procedures of the conventional acid dissolution method that involves multiple complex steps for the preparation of carbonate samples.

First accelerator carbon-14 date for pigment from a rock painting

International Nuclear Information System (INIS)

Van der Merwe, N.J.; Sealy, J.; Yates, R.

1987-01-01

South Africa is particularly blessed with rock art: thousands of paintings and engravings provide a window on the cognitive systems of prehistoric populations. A major stumbling block in studying the art is the lack of a method for dating it. This article shows that some of the paintings can be directly dated by means of accelerator 14 C counting of carbon from black pigment. The advent of accelerator 14 C provides the capability of analysing very small samples and brings pigments from rock paintings into the realm of datable materials

Synthesis of canrenone and related steroids labelled with tritium, carbon-14, and sulfur-35

International Nuclear Information System (INIS)

Markos, C.S.; Dorn, C.R.; Zitzwitz, D.J.

1988-01-01

The syntheses of [1- 3 H]canrenone, [1- 3 H]spironolactone, [1- 3 H] potassium canrenoate, [22- 14 C]canrenone, [22- 14 C]spironolactone, [22- 14 C]potassium canrenoate, and [ 35 S]spironolactone are reported. Tritium labelled compounds were obtained by catalytic reduction of a 3-keto-1, 4-diene precursor followed by exchange of enolizable label. Carbon-14 compounds were obtained by reaction of a 17-ethynyl steroid with 14 CO 2 . Sulfur-35 spironolactone was synthesized by the in-situ generation of [ 35 S]thiolacetic acid from [ 35 S]sodium sulfide. (author)

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)

Hwang, B.K.; Ibenthal, W.-D.; Heitefuss, R.

1986-01-01

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 14 CO 2 assimilation, distribution of 14 C, and 14 C-carbonate uptake in different organs of healthy and infected plants. The reduction of 14 CO 2 assimilation in infected plants at the first and fourth leaf stages was greater in Peruvian than in Asse. In Peruvian, the 14 C 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 14 CO 2 assimilation in noninfected fourth leaves of Asse less than that of Peruvian, but the flow of 14 C 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 14 C-carbonate by seedling roots, the reduction being greater in Peruvian than Asse. A greater proportion of the 14 C 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)

Study of the behaviour of organic carbon in the soil, and carbon 14 study of podzols; Contribution a l'etude du comportement du carbone organique dans le sol et etude des podzols a l'aide du carbone 14

Energy Technology Data Exchange (ETDEWEB)

Nakhla Shawki, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Using the penetration into soil of carbon 14 of thermo-nuclear origin, the behaviour and renewal rate were studied on different organic fractions of the soil. It was established that 18% of the total organic matter is renewed in about 400 years. In addition the formation of podzol-type fossil soils in France was dated from the first millenary B.C., i.e. the end of the sub-boreal period and the beginning of the atlantic period. (author) [French] En utilisant la penetration dans le sol du carbone 14 d'origine thermonucleaire, on a etudie le comportement et la vitesse de renouvellement des differentes fractions de la matiere organique du sol. On a pu preciser que 18% de la matiere organique globale se renouvelait en 400 ans environ. Par ailleurs, la formation en France des sols fossiles du type podzol a ete datee du premier millenaire avant J.C. c'est a dire a la fin de la periode subboreale et au debut de la periode atlantique. (auteur)

Cell Nucleus-Targeting Zwitterionic Carbon Dots.

Science.gov (United States)

Jung, Yun Kyung; Shin, Eeseul; Kim, Byeong-Su

2015-12-22

An innovative nucleus-targeting zwitterionic carbon dot (CD) vehicle has been developed for anticancer drug delivery and optical monitoring. The zwitterionic functional groups of the CDs introduced by a simple one-step synthesis using β-alanine as a passivating and zwitterionic ligand allow cytoplasmic uptake and subsequent nuclear translocation of the CDs. Moreover, multicolor fluorescence improves the accuracy of the CDs as an optical code. The CD-based drug delivery system constructed by non-covalent grafting of doxorubicin, exhibits superior antitumor efficacy owing to enhanced nuclear delivery in vitro and tumor accumulation in vivo, resulting in highly effective tumor growth inhibition. Since the zwitterionic CDs are highly biocompatible and effectively translocated into the nucleus, it provides a compelling solution to a multifunctional nanoparticle for substantially enhanced nuclear uptake of drugs and optical monitoring of translocation.

Improved quality control of carbon-14 labelled compounds

International Nuclear Information System (INIS)

Leonhardt, J.W.; Fuchs, P.; Standtke, K.

1997-01-01

IUT Ltd is a producer of carbon-14 labelled organic compounds like benzene, methanol, phenol, formaldehyde, Na-acetates and also special ordered compounds. The quality control of these compounds is carried out by means of HPLC and GC-MS due to chemical purity. Molar activity was determined by Liquid Scintillation Counting and HPLC being equipped by a radioactivity detector. Unfortunately the accuracy of the activity determination was arrived only ±4% relatively. This error is too high because of the large dilution factors. In respect of the IUT accreditation as an analytical laboratory in Germany the accuracy had to be improved remarkably. Therefore the GC-MS-determination of molar activities of labelled compounds is used as the 14 C-labelled compound. A special evaluation code is used to determine the enrichment values relative to the unlabelled molecules. Taking into account the results of GC-MS the accuracy of molar activity determination is improved to ±2%. The spectra evaluation is demonstrated and some examples are discussed

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. Copyright © 2015 John Wiley & Sons, Ltd.

Differential cross sections for carbon neutron elastic and inelastic scattering from 8.0 to 14.5 MeV

Energy Technology Data Exchange (ETDEWEB)

Haouat, G.; Lachkar, J.; Patin, Y.; Sigaud, J.; Cocu, F.

1975-06-01

Differential elastic and inelastic cross sections for fast neutrons scattered by carbon have been measured between 8.0 and 14.5 MeV. No experimental results on {sup 12}C seem to have been reported, at this time, between 9 and 14 MeV. A complete and consistent set of data on carbon, including total, elastic and inelastic, (n,α) and (n,n'3α) cross sections, is now available for energies below 14.5MeV.

Hofmann elimination of p-nitrophenylethyl-1-C-14-trimethylammonium bromide: a carbon-14 isotope effect study (Preprint no. AR-24)

International Nuclear Information System (INIS)

Ramamurthy, T.V.; Fry, Arthur

1991-01-01

The alpha carbon isotope effects in the Hofmann elimination of p-nitrophenylethyl-1-C-14-trimethylammonium bromide compound have been measured under changing buffer concentrations with a view to correlate mechanistic change. Since there are alpha-carbon isotope effects and the effects are small it is quite likely that the reaction is of the ElcB type, predominately irreversible, with the incursion of slightly increasing fractions of reaction by the reversible mechanism as the buffer concentration is increased. (author). 4 refs., 2 tab

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

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)

1997-12-31

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

Effect of fasting and different diets on 14C incorporation from U-14C glucose into glycogen and carbon dioxide by cerebral cortical slices of rats

International Nuclear Information System (INIS)

Visweswaran, P.; Binod Kumar; Sinha, A.P.; Suraiya, A.; Brahamchari, A.K.; Singh, S.P.

1994-01-01

There are some reports regarding change in the glycogen level due to fasting. Here an attempt is made by keeping the albino rats under fasting or feeding different diets on the rate of 14 C incorporation into glycogen and carbon dioxide from U- 14 C glucose. Our study reveals that the above conditions do not alter any significant change in the glycogen and carbon dioxide in the cerebral cortical slices of albino rats. (author). 8 refs., 1 tab

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

International Nuclear Information System (INIS)

Haag, G.L.

1980-01-01

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 CO 2 -Ba(OH) 2 hydrate gas-solid reaction to directly remove and immobilize carbon-14. The reaction product, BaCO 3 , 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 CO 2 ) gas streams. For the treatment of an air-based off-gas stream, the use of packed beds of Ba(OH) 2 .8H 2 O flakes to remove CO 2 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 .8H 2 O, 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 .8H 2 O to BaCO 3 and not from the hydration of the commercial Ba(OH) 2 .8H 2 O (i.e. Ba(OH) 2 .7.50H 2 O) to Ba(OH) 2 .8H 2 O

Measured neutron carbon kerma factors from 14.1 MeV to 18 MeV

International Nuclear Information System (INIS)

Deluca, P.M.; Barschall, H.H.; McDonald, J.C.

1985-01-01

For A-150 tissue-equivalent plastic, the total neutron kerma is dominated by the hydrogen kerma. Tissue kerma is inferred with reasonable accuracy by normalization to the kerma factor ratio between tissue and A-150 plastic. Because of the close match in the hydrogen abundance in these materials, the principal uncertainty is due to the kerma factors of carbon and oxygen. We have measured carbon kerma factor values of 0.183+-0.015 10 -8 cGy cm 2 and 0.210+-0.016 10 -8 cGy cm 2 at 14.1-MeV and 15-MeV neutron energy, respectively. A preliminary value of 0.297+-0.03 10 -8 cGy cm 2 has been determined at 17.9 MeV. A recent microscopic cross section measurement of the (n,n'3α) reaction in carbon at 14.1-MeV energy gives a kerma factor of 0.184+-0.019 10 -8 cGy cm 2 in agreement with the present result

A simple model for the trapping of deuterons in a carbon target

International Nuclear Information System (INIS)

Erents, S.K.; Hotston, E.S.

1980-01-01

A model is proposed for the trapping of deuterons in an annealed carbon target. The deuterons are assumed to be lodged in traps which are created by the ion beam implanting the deuterons. There is a saturation trap density of 6.8 x 10 22 cm -3 . A deuteron in a region of the target where all the traps are filled is free to execute a random walk until it finds a vacant trap or is released from the target surface. The number of ions trapped per unit area of the target surface has been calculated as a function of ion fluence and is in good agreement with the experimental results. (orig.)

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

High-Resolution Genetics Identifies the Lipid Transfer Protein Sec14p as Target for Antifungal Ergolines.

Directory of Open Access Journals (Sweden)

Ireos Filipuzzi

2016-11-01

Full Text Available Invasive infections by fungal pathogens cause more deaths than malaria worldwide. We found the ergoline compound NGx04 in an antifungal screen, with selectivity over mammalian cells. High-resolution chemogenomics identified the lipid transfer protein Sec14p as the target of NGx04 and compound-resistant mutations in Sec14p define compound-target interactions in the substrate binding pocket of the protein. Beyond its essential lipid transfer function in a variety of pathogenic fungi, Sec14p is also involved in secretion of virulence determinants essential for the pathogenicity of fungi such as Cryptococcus neoformans, making Sec14p an attractive antifungal target. Consistent with this dual function, we demonstrate that NGx04 inhibits the growth of two clinical isolates of C. neoformans and that NGx04-related compounds have equal and even higher potency against C. neoformans. Furthermore NGx04 analogues showed fungicidal activity against a fluconazole resistant C. neoformans strain. In summary, we present genetic evidence that NGx04 inhibits fungal Sec14p and initial data supporting NGx04 as a novel antifungal starting point.

New method of radiation measurement at carbon isotope 14 low level in an environmental atmospheric sampling

International Nuclear Information System (INIS)

Tormos, J.

2009-01-01

A new method of preparation is proposed to extract the atmospheric carbon trapped in the solution of soda coming from air sampling in environment with a carbon-14 bubbler (type H.A.G. 7000). It is based on the neutralisation of the global soda solution got from bubbling pots by nitric acid, the complete desorption of the carbon under gaseous oxidized form (CO 2 ) and its trapping in a only capacity containing a reactive. The whole of the device is scanned by air at steady rate. A test catch of the reactive and of the trapped carbon dioxide is then blended to a glistening liquid (Permafluor E+) and measured in beta counting by scintillation in liquid medium with a counter for the measurement of low energy beta emitters at very low level of activity (Quantulus type). this method allows to get a limit of detection equal to 5 mBq/m 3 for the atmospheric organic carbon. The principal interest of this method is its quickness and simplicity of setting in motion for a measurement of 14 C in the atmospheric carbon dioxide at a level of natural activity. (N.C.)

A study of the carbon dynamics of Japanese grassland and forest using 14C and 13C

International Nuclear Information System (INIS)

Katsuno, Kazumi; Miyairi, Yosuke; Tamura, Kenji; Matsuzaki, Hiroyuki; Fukuda, Kenji

2010-01-01

We quantified the carbon contents of grassland and forest soil using conventional methods and studied the changes in their dynamics by measuring δ 13 C and Δ 14 C. Soil samples were taken from a neighboring Miscanthus sinensis grassland and Pinus densiflora forest in central Japan. Both had been maintained as grassland until the 1960s, when the latter was abandoned and became a pine forest by natural succession. The soil carbon content of the forest was much lower than that of the grassland, implying that the soil carbon decreased as the grassland became forest. The δ 13 C values were very similar in the grassland and forest, at approximately -20 per mille , suggesting that M. sinensis (a C4 plant) contributed to carbon storage, whereas there was little carbon accumulation from P. densiflora (a C3 plant) in forest soil. The Δ 14 C values and calculated soil carbon mean residence time (MRT) showed that the soil carbon in the upper A horizon was older, and that in the lower A horizon was younger in forest than in grassland. From these results, we conclude that young, fast-MRT soil carbon is decomposed in the upper A horizon, and old, stable soil carbon was decomposed in the lower A horizon after the pine invasion.

Carbon-14 tracer study of polyacrylate polymer in a wastewater plant

International Nuclear Information System (INIS)

Martin, J.E.; King, L.W.; Hylko, J.M.

1990-01-01

A highly absorbent consumer-product, polyacrylate-polymer material tagged with carbon-14 ( 14 C), was dosed to a standard on-site aerobic wastewater treatment plant which contained a settling chamber, an aeration chamber, and an effluent chamber. Operation of the test plant was essentially the same as that of a control plant even under exaggerated conditions. About 97% of the polymer material was retained in solids deposited in the primary and aeration chambers, and effluent releases were minimal. The use of a 14 C tagging procedure proved to be a successful method for studying the behavior of these complex materials. It may be useful to conduct a further study on retained solids to determine whether microbial decomposition of the polymer material occurs while they remain in typical plants. (author)

Applications of environmental tritium and carbon-14 in water resources investigation in Taiyuan region China

International Nuclear Information System (INIS)

Cai Zuhuang; Shi Huixin

1988-01-01

To evaluate the influence of exploiting karst groundwater by 0.5-1 cubic metre per second by Gujiao Coal Mine on the discharge rate of the major Lancun spring, Jinci spring and Xizhang waterworks in the Taiyuan region, Shanxi Province, and to seek new sources of water to make up for this influence, we carried out systematic hydrogeological studies in this region from 1983 to 1986, including measurement of 180 data of tritium, 49 data of carbon-13, 20 data of carbon-14, as well as more than 2,000 chemical data. Isotopic and chemical data were interpreted and used to distinguish the groundwater system, to determine the mixing ratios of various groundwaters, to trace the movement of groundwater both inside each subsystem and from one subsystem to another. Groundwater ages at 13 sites in the studied region were obtained after correction for mixing with young water, correction for dilution by dead carbon, and correction for variation of initial carbon-14 concentration. The velocity of groundwater flow was determined on the basis of groundwater ages. (author). 3 figs, 5 tabs

A novel llama antibody targeting Fn14 exhibits anti-metastatic activity in vivo.

Science.gov (United States)

Trebing, Johannes; Lang, Isabell; Chopra, Martin; Salzmann, Steffen; Moshir, Mahan; Silence, Karen; Riedel, Simone S; Siegmund, Daniela; Beilhack, Andreas; Otto, Christoph; Wajant, Harald

2014-01-01

Expression of fibroblast growth factor (FGF)-inducible 14 (Fn14), a member of the tumor necrosis factor receptor superfamily, is typically low in healthy adult organisms, but strong Fn14 expression is induced in tissue injury and tissue remodeling. High Fn14 expression is also observed in solid tumors, which is why this receptor is under consideration as a therapeutic target in oncology. Here, we describe various novel mouse-human cross-reactive llama-derived recombinant Fn14-specific antibodies (5B6, 18D1, 4G5) harboring the human IgG1 Fc domain. In contrast to recombinant variants of the established Fn14-specific antibodies PDL192 and P4A8, all three llama-derived antibodies efficiently bound to the W42A and R56P mutants of human Fn14. 18D1 and 4G5, but not 5B6, efficiently blocked TNF-like weak inducer of apoptosis(TWEA K) binding at low concentrations (0.2–2 μg/ml). Oligomerization and Fcγ receptor (FcγR) binding converted all antibodies into strong Fn14 agonists. Variants of 18D1 with enhanced and reduced antibody-dependent cell-mediated cytotoxicity (ADCC) activity were further analyzed in vivo with respect to their effect on metastasis. In a xenogeneic model using human colon carcinoma cancer cells, both antibody variants were effective in reducing metastasis to the liver. In contrast, only the 18D1 variant with enhanced ADCC activity, but not its ADCC-defective counterpart, suppressed lung metastasis in the RE NCA model. In sum, this suggests that Fn14 targeting might primarily act by triggering of antibody effector functions, but also by blockade of TWEA K-Fn14 interaction in some cases

Carbon 14 in the aquatic food chain

International Nuclear Information System (INIS)

Mueller, H.; Fischer, E.

1983-01-01

In the links of the food chain consisting of water, water plants, and fish from 6 several aquatic ecosystems, the specific C-14 activity of the carbon was determined from 1979 to 1981 and compared with values of the terrestrial food chain. The mean values obtained from the specific acitivities of the links were between 203 and 321 mBq/g C (5.5 and 8.7 pCi/g C). Four of the six mean values differ from the values for the terrestrial food chain of 260 to 240 mBg/g C (7.0 to 6.5 pCi/g C) investigated for 1979 to 1980. The specific-acitivity model is valid for the aquatic food chain only if atmosphere and man are not included as chain links. (orig.) [de

A study for the fabulously of introducing an acceleration mass spectrometer facility (ABMs) for carbon-14 applications

International Nuclear Information System (INIS)

Aly, A.I.M.; Comsan, N.; Sadek, M.

2004-01-01

In this work a study was conducted to show the importance and feasibility of introducing an accelerating mass spectrometer facility for carbon-14 analysis in the environmental levels. The different applications of Carbon-14 (e.g. dating and identification of food additives of synthetic origin) are discussed. There are two methods for C- 14 measurements, beta decay counting and accelerator mass spectrometry (AMS). The beta decay method requires gram quantities of the sample carbon, compared to few milligram quantities in case of AMS method. The Central Lab. for Environmental Isotope Hydrology of the National Center for Nuclear Safety and Radiation Control has a Carbon-14 analysis facility based on beta decay counting using a liquid scintillation counter after sample preparation in the form of benzene through rather complicated chemical conversion steps. This strongly limits the capacity of the laboratory to about 100-150 samples per year. Also, the amount of sample required limits our expansion for some very important applications like dating of archaeological small samples and especially old bone samples which normally have a low concentration of organic compounds. These applications are only possible by using the AMS method. For some applications only AMS could be used e.g measuring C-14 in atmospheric gases such as methane and carbon dioxide is virtually impossible using decay counting but quite feasible with AMS. The importance of purchasing an AMS facility or upgrading the existing accelerator is discussed in view of the shortage of such a facility in Africa and the Middle East. Acquiring an AMS in Egypt will make it possible to accurately date the Egyptian antiquities and to act as a regional laboratory and to enter into new applications where the amount of sample is limiting

The application of carbon nanotubes in target drug delivery systems for cancer therapies

Science.gov (United States)

Zhang, Wuxu; Zhang, Zhenzhong; Zhang, Yingge

2011-10-01

Among all cancer treatment options, chemotherapy continues to play a major role in killing free cancer cells and removing undetectable tumor micro-focuses. Although chemotherapies are successful in some cases, systemic toxicity may develop at the same time due to lack of selectivity of the drugs for cancer tissues and cells, which often leads to the failure of chemotherapies. Obviously, the therapeutic effects will be revolutionarily improved if human can deliver the anticancer drugs with high selectivity to cancer cells or cancer tissues. This selective delivery of the drugs has been called target treatment. To realize target treatment, the first step of the strategies is to build up effective target drug delivery systems. Generally speaking, such a system is often made up of the carriers and drugs, of which the carriers play the roles of target delivery. An ideal carrier for target drug delivery systems should have three pre-requisites for their functions: (1) they themselves have target effects; (2) they have sufficiently strong adsorptive effects for anticancer drugs to ensure they can transport the drugs to the effect-relevant sites; and (3) they can release the drugs from them in the effect-relevant sites, and only in this way can the treatment effects develop. The transporting capabilities of carbon nanotubes combined with appropriate surface modifications and their unique physicochemical properties show great promise to meet the three pre-requisites. Here, we review the progress in the study on the application of carbon nanotubes as target carriers in drug delivery systems for cancer therapies.

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.)

Synthesis of carbon-14-labeled sodium palmoxirate and its coenzyme A ester

Energy Technology Data Exchange (ETDEWEB)

Weaner, L.E.; Hoerr, D.C.

1986-04-01

Synthetic procedures for the preparation of carbon-14-labeled sodium palmoxirate (TDGA), labeled either in the carboxyl position or in the tetradecyl hydrocarbon chain, are described. In addition, the synthesis of the coenzyme A ester of TDGA-14C with a specific activity of 51 mCi/mmol is reported. The coenzyme A ester was prepared by formation of the acyl chloride with oxalyl chloride followed by reaction with coenzyme A (CoA) in a borate-buffered tetrahydrofuran solution. Purification methods and analytical and stability data are reported for the compounds.

Biomeasures and mechanistic modeling highlight PK/PD risks for a monoclonal antibody targeting Fn14 in kidney disease.

Science.gov (United States)

Chen, Xiaoying; Farrokhi, Vahid; Singh, Pratap; Ocana, Mireia Fernandez; Patel, Jenil; Lin, Lih-Ling; Neubert, Hendrik; Brodfuehrer, Joanne

2018-01-01

Discovery of the upregulation of fibroblast growth factor-inducible-14 (Fn14) receptor following tissue injury has prompted investigation into biotherapeutic targeting of the Fn14 receptor for the treatment of conditions such as chronic kidney diseases. In the development of monoclonal antibody (mAb) therapeutics, there is an increasing trend to use biomeasures combined with mechanistic pharmacokinetic/pharmacodynamic (PK/PD) modeling to enable decision making in early discovery. With the aim of guiding preclinical efforts on designing an antibody with optimized properties, we developed a mechanistic site-of-action (SoA) PK/PD model for human application. This model incorporates experimental biomeasures, including concentration of soluble Fn14 (sFn14) in human plasma and membrane Fn14 (mFn14) in human kidney tissue, and turnover rate of human sFn14. Pulse-chase studies using stable isotope-labeled amino acids and mass spectrometry indicated the sFn14 half-life to be approximately 5 hours in healthy volunteers. The biomeasures (concentration, turnover) of sFn14 in plasma reveals a significant hurdle in designing an antibody against Fn14 with desired characteristics. The projected dose (>1 mg/kg/wk for 90% target coverage) derived from the human PK/PD model revealed potential high and frequent dosing requirements under certain conditions. The PK/PD model suggested a unique bell-shaped relationship between target coverage and antibody affinity for anti-Fn14 mAb, which could be applied to direct the antibody engineering towards an optimized affinity. This investigation highlighted potential applications, including assessment of PK/PD risks during early target validation, human dose prediction and drug candidate optimization.

Carbon transfer between 2 1/4 Cr 1 Mo alloy and austenitic steels (experiments in anisothermal loops)

International Nuclear Information System (INIS)

Baque, P.; Besson, M.; Champeix, L.; Donati, J.R.; Oberlin, C.; Saint-Paul, P.

1976-01-01

Studies on carbon transfer between the ferritic steel 2 1/4 Cr 1 Mo and the austenitic steels 316L and 321H have shown that there is not any measurable carbon transfer in the operating conditions of the secondary circuit of PHENIX (475 deg C was the maximal temperature of the 2 1/4 Cr 1 Mo steel). A significant carbon transfer has been observed between the ferritic steel and the 316L steel when the 321H was replaced by the 2 1/4 Cr 1 Mo steel in the same thermohydraulic conditions (the ferritic steel was then used up to 545 deg C). This experiment has demonstrated the importance of the temperature and the initial carbon content of the ferritic steel as parameters in the decarburization process. It appears that decarburization may not be sensitive to the thermohydraulic conditions at least in the range investigated in those experiments. In the other hand the 316L steel is observed to have been carburized, the degree of carburization remaining appreciably constant and independent on the temperature between 400 deg C and 550 deg C [fr

An assessment of the inventory of Carbon-14 in the oceans

International Nuclear Information System (INIS)

Lassey, K.R.; Manning, M.R.; O'Brien, B.J.

1987-04-01

The oceanic inventory for natural 14 C is 19.6x10 29 atoms, an estimate similar to those found by other methods. The 14 C produced from nuclear weapons (1972) is 550x10 26 atoms and 52% was in the oceans. From 1972 to 1985 132x10 26 atoms of bomb 14 C were added. The nuclear power industry produces 0.5x10 26 atoms per year (17% of natural production rate). Most estimates by varying methods indicate an exchange time of carbon from atmosphere to ocean of about seven years or about 22 moles m -2 yr -1 for the surface ocean. The oceanic distribution generally has higher concentrations in low to mid latitudes, and low concentrations in the most southern regions, with the deep ocean retaining levels similar to those before nuclear testing

Measured neutron carbon kerma factors from 14.1 MeV to 18 MeV

International Nuclear Information System (INIS)

Deluca, P.M. Jr.; Barschall, H.H.; Haight, R.C.; McDonald, J.C.

1984-01-01

For A-150 tissue-equivalent plastic, the total neutron kerma is dominated by the hydrogen kerma. Tissue kerma is inferred with reasonable accuracy by normalization to the kerma factor ratio between tissue and A-150 plastic. Because of the close match in the hydrogen abundance in these materials, the principal uncertainty is due to the kerma factors of carbon and oxygen. We have measured carbon kerma factor values of 0.183 +- 0.015 10 -8 cGy cm 2 and 0.210 +- 0.16 10 -8 cGy cm 2 at 14.1-MeV and 15-MeV neutron energy, respectively. A preliminary value of 0.297 +- 0.03 10 -8 cGy cm 2 has been determined at 17.9 MeV. A recent microscopic cross section measurement of the (n,n'3α) reaction in carbon at 14.1-MeV energy gives a kerma factor of 0.184 +- 0.019 10 8 cGy cm 2 in agreement with the present result. 9 refs., 4 figs., 2 tabs

Path towards achieving of China's 2020 carbon emission reduction target-A discussion of low-carbon energy policies at province level

International Nuclear Information System (INIS)

Wang Run; Liu Wenjuan; Xiao Lishan; Liu Jian; Kao, William

2011-01-01

Following the announcement of the China's 2020 national target for the reduction of the intensity of carbon dioxide emissions per unit of GDP by 40-45% compared with 2005 levels, Chinese provincial governments prepared to restructure provincial energy policy and plan their contribution to realizing the State reduction target. Focusing on Fujian and Anhui provinces as case studies, this paper reviews two contrasting policies as a means for meeting the national reduction target. That of the coastal province of Fujian proposes to do so largely through the development of nuclear power, whilst the coal-rich province of Anhui proposes to do so through its energy consumption rate rising at a lower rate than that of the rise in GDP. In both cases renewable energy makes up a small proportion of their proposed 2020 energy structures. The conclusion discusses in depth concerns about nuclear power policy, energy efficiency, energy consumption strategy and problems in developing renewable energy. - Research Highlights: → We review two contrasting policies as a means for meeting the national reduction target of carbon emission in two provinces. → Scenario review of energy structure in Fujian and Anhui Provinces to 2020. → We discuss concerns about nuclear power policy, energy efficiency, energy consumption strategy and problems in developing renewable energy.

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.

Effect of IX column maintenance on carbon-14 concentration in moderator systems

International Nuclear Information System (INIS)

Gallagher, C.L.; Tripple, A.W.

2006-01-01

The radionuclide 14 C is produced in CANDU reactors primarily by the (n,α) reaction with 17 O. Because of high neutron fluxes in the core, the majority of the 14 C (94.5%) is produced in the moderator. In the moderator system, 14 C is present mainly as CO 2 in the cover gas in dynamic equilibrium with dissolved carbonates, bicarbonates and CO 2 in the moderator water. Emissions of 14 C from reactors occur through venting or leakage of the cover gas. By controlling the dissolved carbonates in the moderator water with an ion exchange (IX) purification system, the amount of 14 C in the cover gas is minimized and thus the emissions of 14 C can be reduced. A study was conducted to measure the 14 C concentrations in the moderator system at Gentilly 2 in order to determine the effectiveness of the purification system in removing 14 C. Moderator water samples were obtained from the inlet and outlet of the purification system from 2004 January 14 to July 12, covering the operation of two IX columns (IX-1 and IX-3). The moderator water samples contained high levels of tritium (∼2 TBq·L -1 ). As both tritium and 14 C are β-radiation emitters, direct counting of moderator water for 14 C is impossible as the signal due to tritium dominates over that of other β-emitters. Therefore, a procedure developed by Caron et al. was used in this study, which involved acidifying the sample to release the dissolved 14 CO 2 as gas and collecting the 14 CO 2 in a base (NaOH), which could then be measured by liquid scintillation counting to determine the 14 C concentration. Both of the IX columns started with 14 C removal efficiencies of about 95%. The efficiency began to decrease almost immediately with the IX-1 column dropping to 80% efficiency after ∼1115 hours. This drop in efficiency also led to an increase in the inlet concentration over time. IX-1 column was removed from service after ∼1745 hours with a 14 C removal efficiency of ∼31%. IX-3 column was then placed in service

Carbon-14 kinetic isotope effects and mechanisms of addition of 2,4-dinitrobenzenesulfenyl chloride to substituted styrenes-1-14C and styrenes-2-14C

International Nuclear Information System (INIS)

Kanska, M.; Fry, A.

1983-01-01

As the first reported examples of carbon isotope effects in simple electrophilic addition reactions we have measured the carbon-14 kinetic isotope effects in the addition of 2,4-dinitrobenzenesulfenyl chloride to a series of para-substituted α and β-labeled styrenes in acetic acid at 30.1 0 C: for para substituents Cl, H, and CH 3 the k/ 14 K values for α labeling are 1.027, 1.022, and 1.004, and the k/ 14 k values for β labeling are 1.035, 1.032, and 1.037, all +/-approx.0.004. The kinetics of the reaction were measured for the p-CH 3 O,p-CH 3 , unsubstituted, p-Cl, and m-NO 2 styrenes; electron-donating groups strongly accelerate the reaction, and electron-withdrawing groups retard it. The Hammett plot is curved with p + values ranging from about -4.6 at the electron-donating group (EDG) end to about -1.8 at the electron-withdrawing group (EWG) end. Both the isotope effect and kinetic data, and related data from the literature, are interpreted in terms of a changing mechanism, with the activated complexes of the rate-determining steps having much open carbenium ion (ion pair) character for EDG-substituted styrenes and much cyclic thiiranium io (ion par) character for EWG-substituted styrenes. 1 figure, 2 tables

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

International Nuclear Information System (INIS)

Loheac, J.

1966-06-01

Several new syntheses of δ aminolevulic acid (δ A.L.A.) have been studied. 14 C-4 δ - aminolevulic acid has been obtained from 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 14 C-1 or 14 C-2 δ-A.L.A. has been prepared from the 14 C-1 or 14 C-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) [fr

Distribution of Δ14C in western North Pacific and tracing carbons of human origin

International Nuclear Information System (INIS)

Aramaki, Takafumi; Mizushima, Toshihiko; Togawa, Orihiko; Kuji, Tomoyuki

2001-01-01

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. 14 C concentration was calculated from δ 13 C value calculated from the 13 C/ 12 C ratio. 14 C resulting from the nuclear weapon test was calculated by comparing estimated 14 C and real 14 C concentration. It was compared with that in 1970s. 14 Cbomb has dissolved into North Pacific Intermediate Water in Arctic latitude, which has moved to Mid-latitude. (A. Yamamoto)

Carbon-14 urea utilization in diagnosis of the presence Campylobacter pylori in stomach

International Nuclear Information System (INIS)

Chausson, Y.

1989-01-01

A new method to detect the Campylobacter pylori in the stomach, using carbon-14 urea is presented. The technique consists in after the tracer ingestion, the tracer is recuperated by the expiration way in organic hiamin and after counting and evaluating. (M.L.J.)

Investigations on the biokinetics of carbon 14 in algae cultures

International Nuclear Information System (INIS)

Leister, W.

1981-01-01

The uptake of 14 C by Scenedesmus quadricauda is quantitatively investigated by simulation models of radio ecological relevance. Due to the complexing of the procedures in the natural ecosystem, it was only possible to consider idealized conditions. The batch culture ressembles the conditons of still waters or relatively still waters without notable water exchange. The effect of the 14 C enrichment, as well as the drastic carbon reduction in the substrate as a result of algae growth, was avoided in the modified batch culture under conditions of simultaneous substrate diffusion by means of a permeation system. The 14 C and 12 C uptake of the cells thus took place solely under the conditions of constant concentration in the culture medium. The consequences for flowing water resulting from a nuclear power plant accident are to be simulated for the extent of the 14 C uptake by green algae using the continuous culture model with dynamic 14 C exposure. The continuous infusion of 14 C in the continuous culture corresponds to the possible cases where 14 C escapes into a flowing water at a constant rate over a long period of time, whether this may be via chronical release from a nuclear power plant or by 'fallout' resulting from nuclear arms testing. The results shown lead to the conclusion that the emission of 14 C to the environment, which according to prognoses will be considerably higher after the year 2000, presents a serious radioactivity potential which man and environment will have to live with should these developments continue and the prognoses come true. (orig./MG) [de

Systematical investigations of the emission of carbon 14 from a TRIGA-Mark-II reactor - methods and results

International Nuclear Information System (INIS)

Pfeiffer, K.J.

1981-01-01

Almost no information is available about the extent of the carbon-14 releases from a research reactor. For this reason this report is dealing with the emission of C-14 from the Vienna TRIGA-Mark-II reactor. In addition the resulting radiation exposure is estimated. Due to the low activity concentrations of C-14 in research reactor effluents special requirements are necessary for sampling and measuring. A technique providing both sufficient lower limit of detection and little effort of sample preparation was developed. Carbon dioxide was trapped by bubbling air taken from the stack through washing bottles containing an aqueous solution of sodium hydroxide. After sampling a precipitate of CaCO 3 was formed and about 8 g of calcium carbonate were counted as a gel suspension by liquid scintillation counting. The formation of the gel was provided by mixing water with a scintillation cocktail originally developed for uptake of high quantities of aqueous solutions. The resulting lower limit of detection was about 50 Bq/kg carbon being equivalent to 9mBq/m 3 air. Concluding the measurements, which were carried out by weekly counting and a period of some 14 months, a normalized release rate of about 280 Bq (7, 1μCi) was found. This release rate is somewhat higher than the reported values for power reactors, because the main activity is produced by activation of air in experimental equipments. (author)

Target vs. background discrimination using multispectral data in 1.5-14.5 micron

Science.gov (United States)

Cogliandro, Santo; Panizza, Marco; Castelli, Paola

1987-01-01

LOWTRAN V model calculations are compared to experimental spectral background radiance and spectral transmittance data in the 1.5 to 14.5-micron band, in order to identify the most important parameters affecting the discrimination of targets from background. Attention is accordingly given to the IR energy emitted by a reference plate at different values of temperature and emissivity vs various previously investigated backgrounds. Targets at near-ambient temperature are also considered.

Carbon-14 speciation during anoxic corrosion of activated steel in a repository environment

Energy Technology Data Exchange (ETDEWEB)

Wieland, E.; Cvetkovic, B.Z.; Kunz, D. [Paul Scherrer Institute, Villigen (Switzerland). Lab. for Waste Management; Salazar, G.; Szidat, S. [Bern Univ. (Switzerland). Dept. of Chemistry and Biochemistry and Oeschger Centre for Climate Change Research

2018-01-15

Radioactive waste contains significant amounts of {sup 14}C which has been identified a key radionuclide in safety assessments. In Switzerland, the {sup 14}C inventory of a cement-based repository for low- and intermediate-level radioactive waste (L/ILW) is mainly associated with activated steel (∝85 %). {sup 14}C is produced by {sup 14}N activation in steel parts exposed to thermal neutron flux in light water reactors. Release of {sup 14}C occurs in the near field of a deep geological repository due to anoxic corrosion of activated steel. Although the {sup 14}C inventory of the L/ILW repository and the sources of {sup 14}C are well known, the formation of {sup 14}C species during steel corrosion is only poorly understood. The aim of the present study was to identify and quantify the {sup 14}C-bearing carbon species formed during the anoxic corrosion of iron and steel and further to determine the {sup 14}C speciation in a corrosion experiment with activated steel. All experiments were conducted in conditions similar to those anticipated in the near field of a cement-based repository.

Carbon Nanotubes: An Emerging Drug Carrier for Targeting Cancer Cells

Science.gov (United States)

Bhattacharya, Shiv Sankar; Mishra, Arun Kumar; Verma, Navneet; Verma, Anurag; Pandit, Jayanta Kumar

2014-01-01

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

PEGylated anticancer-carbon nanotubes complex targeting mitochondria of lung cancer cells

Science.gov (United States)

Kim, Sang-Woo; Lee, Yeon Kyung; Lee, Jong Yeon; Hong, Jeong Hee; Khang, Dongwoo

2017-11-01

Although activating apoptosis in cancer cells by targeting the mitochondria is an effective strategy for cancer therapy, insufficient targeting of the mitochondria in cancer cells restricts the availability in clinical treatment. Here, we report on a polyethylene glycol-coated carbon nanotube (CNT)-ABT737 nanodrug that improves the mitochondrial targeting of lung cancer cells. The polyethylene glycol-coated CNT-ABT737 nanodrug internalized into the early endosomes via macropinocytosis and clathrin-mediated endocytosis in advance of early endosomal escape and delivered into the mitochondria. Cytosol release of the nanodrug led to apoptosis of lung cancer cells by abruption of the mitochondrial membrane potential, inducing Bcl-2-mediated apoptosis and generating intracellular reactive oxygen species. As such, this study provides an effective strategy for increasing the anti-lung cancer efficacy by increasing mitochondria accumulation rate of cytosol released anticancer nanodrugs.

Low-level (submicromole) environmental 14C metrology

International Nuclear Information System (INIS)

Currie, L.A.; Kessler, J.D.; Marolf, J.V.; McNichol, A.P.; Stuart, D.R.; Donoghue, J.C.; Donahue, D.J.; Burr, G.S.; Biddulph, D.

2000-01-01

Accelerator mass spectrometry (AMS) measurements of environmental 14 C have been employed during the past decade at the several micromole level (tens of μg carbon), but advanced research in the atmospheric and marine sciences demands still higher (μg) sensitivity, an extreme example being the determination of 14 C in elemental or 'black' carbon (BC) at levels of 2-10 μg per kg of Greenland snow and ice (Currie et al., 1998). A fundamental limitation for 14 C AMS is Poisson counting statistics, which sets in at about 1 μg modern-C. Using the small sample (25 μg) AMS target preparation facility at NOSAMS (Pearson et al., 1998), and the microsample combustion-dilution facility at NIST, we have demonstrated an intrinsic modern-C quantification limit (m Q ) of ca. 0.9 μg, based on a 1-parameter fit to the empirical AMS variance function. (For environmental 14 C, the modern carbon quantification limit is defined as that mass (m Q ) corresponding to 10% relative standard deviation (rsd) for the fraction of modern carbon, σ(f M )/f M .) Stringent control, required for quantitative dilution factors (DL), is achieved with the NIST on-line manometric/mass spectrometry facility that compensates also for unsuspected trace impurities from vigorous chemical processing (e.g., acid digestion). Our current combustion blank is trivial (mean: 0.16 ± 0.02 μg C, n=13) but lognormally distributed (dispersion [σ]: 0.07 ± 0.01 μg). An iterative numerical expression is introduced to assess the quantitative impacts of fossil and modern carbon blank components on m Q ; and a new 'clean chemistry' BC processing system is described for the minimization of such blanks. For the assay of soot carbon in Greenland snow/ice, the overall processing blank has been reduced from nearly 7 μg total carbon to less than 1 μg, and is undetectable for BC

Contribution of deep sourced carbon from hydrocarbon seeps to sedimentary organic carbon: Evidence from Δ14C and δ13C isotopes

Science.gov (United States)

Feng, D.; Peckmann, J.; Peng, Y.; Liang, Q.; Roberts, H. H.; Chen, D.

2017-12-01

Sulfate-driven anaerobic oxidation of methane (AOM) limits the release of methane from marine sediments and promotes the formation of carbonates close to the seafloor along continental margins. It has been established that hydrocarbon seeps are a source of dissolved inorganic and organic carbon to marine environments. However, questions remain about the contribution of deep sourced carbon from hydrocarbon seeps to the sedimentary organic carbon pool. For a number of hydrocarbon seeps from the South China Sea and the Gulf of Mexico, the portion of modern carbon was determined based on natural radiocarbon abundances (Δ14C) and stable carbon isotope (δ13Corganic carbon) compositions of the non-carbonate fractions extracted from authigenic carbonates. Samples from both areas show a mixing trend between ideal planktonic organic carbon (δ13C = -22‰ VPDB and 90% modern carbon) and the ambient methane. The δ13Corganic carbon values of non-carbonate fractions from three ancient seep deposits (northern Italy, Miocene; western Washington State, USA, Eocene to Oligocene) confirm that the proxy can be used to constrain the record of sulfate-driven AOM through most of Earth history by measuring the δ13C values of organic carbon. This study reveals the potential of using δ13C values of organic carbon to discern seep and non-seep environments. This new approach is particularly promising when authigenic carbonate is not present in ancient sedimentary environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support of the deep-sea dives. Funding was provided by the NSF of China (Grants: 41422602 and 41373085).

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).

Carbon-14 in sludge

International Nuclear Information System (INIS)

Fowler, J.R.; Coleman, C.J.

1983-01-01

The level of C-14 in high-level waste is needed to establish the amount of C-14 that will be released to the environment either as off-gas from the Defense Waste Processing Facility (DWPF) or as a component of saltstone. Available experimental data confirmed a low level of C-14 in soluble waste, but no data was available for sludge. Based on the processes used in each area, Purex LAW sludge in F-area and HM HAW sludge in H-area will contain the bulk of any sludge produced by the cladding. Accordingly, samples from Tank 8F containing Purex LAW and Tank 15H containing HM HAW were obtained and analyzed for C-14. These two waste types constitute approximately 70% of the total sludge inventory now stored in the waste tanks. Results from analyses of these two sludge types show: the total C-14 inventory in sludge now stored in the waste tanks is 6.8 Ci; C-14 releases to the atmosphere from the DWPF will average approximately 0.6 Ci annually at the projected sludge processing rate in the DWPF. 4 references, 2 tables

Validation of a simplified carbon-14-urea breath test for routine use for detecting Helicobacter pylori noninvasively

International Nuclear Information System (INIS)

Henze, E.; Malfertheiner, P.; Clausen, M.; Burkhardt, H.; Adam, W.E.

1990-01-01

A carbon-14 ( 14 C) urea breath test for detecting Helicobacter pylori with multiple breath sampling was developed. Carbon-14-urea (110 kBq) administered orally to 18 normal subjects and to 82 patients with Helicobacter infection. The exhaled 14 C-labeled CO 2 was trapped at 10-min intervals for 90 min. The total 14 C activity exhaled over 90 min was integrated and expressed in %activity of the total dose given. In normals, a mean of 0.59% +/- 0.24% was measured, resulting in an upper limit of normal of 1.07%. In 82 patients, a sensitivity of 90.2%, a specificity of 83.8%, and a positive predictive value of 90.2% was found. The single probes at intervals of 40-60 min correlated best with the integrated result, with r ranging from 0.986 to 0.990. The test's diagnostic accuracy did not change at all when reevaluated with the 40-, 50-, or 60-min sample data alone. Thus, the 14 C-urea breath test can be applied routinely as a noninvasive, low-cost and one-sample test with high diagnostic accuracy in detecting Helicobacter pylori colonization

Measurement of carbon-14 in hydrological samples

International Nuclear Information System (INIS)

Hussain, S.D.

1991-11-01

Thermal neutrons produced by cosmic rays or nuclear weapon tests interact with atmospheric nitrogen resulting in the formation of radiocarbon which, after oxidation into carbon dioxide, follows the natural carbon cycle. The partial pressure of carbon dioxide in the soil is several times that in the atmosphere due to plant root respiration and decay of organic matter. Water absorbs biogenic carbon dioxide while percolating through the unsaturated zone. The carbon content of groundwater is mainly in the form of bicarbonate ions. The extraction of carbon from water sample as barium carbonate is carried out in the field. Benzene is synthesised from the carbonate sample. The activity of radiocarbon in the synthesised benzene is determined by using a liquid scintillation analyzer. Details of sampling procedure, benzene synthesis, counter calibration and treatment of sample data have been given. 7 figs. (author)

Carbon-14 in the biosphere: Modeling and supporting research for the Canadian Nuclear Fuel Waste Management program

International Nuclear Information System (INIS)

Sheppard, S.C.; Amiro, B.D.; Sheppard, M.I.; Stephenson, M.; Zach, R.; Bird, G.A.

1994-01-01

Carbon-14 stands apart from most of the radionuclides present in nuclear fuel waste for several reasons. It has a relatively long radiological half-life and low retardation by granitic geological media so that 14 C is superceded only by 36 Cl and 129 I in potential release to the biosphere from unprocessed used fuel. In the biosphere, its importance continues because it is readily incorporated into the carbon compounds of life. Much of the behavior of 14 C in the biosphere can be conceptualized as isotopic exchange, where the 14 C mixes with 12 C from the biosphere. However, because of lack of data, the authors model the behavior of 14 C only partly as isotopic exchange, with most of the calculations relying on compartment transfer models. The authors experimental work has shown that soil-to-plant transfer may be dominated by the soil-atmosphere-plant pathway. Gaseous loss of 14 C from soils and lakes is significant. However, recalcitrant forms may persist in soils and sediments for long time periods. The impact of these forms is expected to be relatively low because their bioavailability is correspondingly low. Future research should be directed to support full modeling of 14 C as a series of isotopic exchange processes

Tests of intestinal absorption using carbon-14-labeled isotopes

International Nuclear Information System (INIS)

Fromm, H.; Sarva, R.P.

1983-01-01

Beta radiation-emitting isotopes are being used increasingly in diagnostic gastroenterology for the study of absorption. The major reason for the popularity of radioisotopes is that their use is convenient for patient and physician alike. They often obviate naso- or orointestinal intubation and the collection, storage, and analysis of stool. The radioactivity used for the studies of digestive and absorptive processes is small and is not hazardous. In spite of the safety of the radiolabeled compounds, their use is restricted in children and pregnant women. Therefore, for most tests, promising alternative methods that make use of the stable isotope of carbon, /sup 13/C, instead of the radioactive /sup 14/C have been developed. The analysis of stable isotopes requires more sophisticated technology than that of radioactive compounds, however. Only a few centers presently are equipped and staffed to analyze stable isotopes on a routine basis. In contrast, the analysis of radioactive isotopes has become a routine procedure in almost ever major laboratory. The last decade has brought the development of several radioactive absorption tests. The clinically most useful tests relate to the study of bile acid, fat, lactose, and xylose absorption. All of these tests utilize the excretion rate of /sup 14/CO/sub 2/ in breath after ingestion of a /sup 14/C-labeled compound as a measure of the rate of its absorption or malabsorption

In situ synthesis of N and Cu functionalized mesoporous FDU-14 resins and carbons for electrochemical hydrogen storage

Energy Technology Data Exchange (ETDEWEB)

Kong, AiGuo; Wang, WenJuan; Yang, Fan; Ding, HanMing; Shan, YongKui [Department of Chemistry, East China Normal University, ShangHai 200062 (China)

2010-07-15

N and Cu cooperatively functionalized mesoporous resin and carbon materials with bicontinuous cubic structure (FDU-14) were obtained by a novel synthesis method. In this method, block copolymers were used as the templates as well as the precursors for the preparation of these modifying mesoporous materials. The CuC{sub 2}O{sub 4} in the channels of mesoporous FDU-14 resins was gotten by in situ oxidation of the templates in a catalytic redox system containing Cu{sup 2+}, Al{sup 3+}, NO{sub 3}{sup -}, PO{sub 4}{sup 3-}, SO{sub 4}{sup 2-} ions. Simultaneously, the phenol-formaldehyde resin frameworks were in situ functionalized by the amine group resulting from the reduction of NO{sub 3}{sup -}, leading to the formation of N and CuC{sub 2}O{sub 4} modified mesoporous FDU-14 resin materials. Its pyrolysis at the different temperatures resulted in the production of N and Cu cooperatively functionalized mesoporous FDU-14 resin and carbon materials. The structure and composition of these materials were characterized by the X-ray power diffraction, transmission electron microscopy, N{sub 2} adsorption-desorption analysis, X-ray photoelectron spectroscopy, infrared spectroscopy, thermogravimetry analysis, and inductive coupled plasma emission spectroscopy. The electrochemical measurement indicated that N and Cu cooperatively functionalized mesoporous FDU-14 carbon materials possessed the enhanced electrochemical hydrogen storage performance. (author)

Synthesis and solubility measurement in supercritical carbon dioxide of two solid derivatives of 2-methylnaphthalene-1,4-dione (menadione): 2-(Benzylamino)-3-methylnaphthalene-1,4-dione and 3-(phenethylamino)-2-methylnaphthalene-1,4-dione

International Nuclear Information System (INIS)

Zacconi, Flavia C.; Nuñez, Olga N.; Cabrera, Adolfo L.; Valenzuela, Loreto M.

2016-01-01

Highlights: • Two menadione derivatives were synthesized, purified and characterized. • Solubility of menadione derivatives in SC-CO 2 was measured at T < 333 K, p < 28 MPa. • Thermodynamic consistency of solubility data measured was evaluated. • Solubility data was correlated in terms of temperature and CO 2 density. - Abstract: Synthesis of two solid derivatives of vitamin K 3 (2-methylnaphthalene-1,4-dione or menadione), 2-(benzylamino)-3-methylnaphthalene-1,4-dione and 3-(phenethylamino)-2-methylnaphthalene-1,4-dione was completed using a 1,4 Michael addition reaction at 323 K in an inert atmosphere, with reaction yields of 62% mol·mol −1 and 71% mol·mol −1 , respectively, and a purity grade of 98% mol·mol −1 for each component. Isothermal solubility (mole fraction) of each solid derivative in supercritical carbon dioxide was performed using an analytic-recirculation methodology, with direct determination of the molar composition of the carbon dioxide-rich phase by using high performance liquid chromatography, at temperatures of (313, 323 and 333) K and pressures from (8–28) MPa. Results indicated that the range of measured solubilities were from (59 × 10 −6 to 368 × 10 −6 ) mol·mol −1 for solid 2-(benzylamino)-3-methylnaphthalene-1,4-dione and from (40 × 10 −6 to 205 × 10 −6 ) mol·mol −1 for solid 3-(phenethylamino)-2-methylnaphthalene-1,4-dione. The experimental solubility was validated using three approaches, estimating the combined expanded uncertainty of measurement for each solubility data point, evaluating the thermodynamic consistency of the data utilizing a test based on the Gibbs–Duhem equation, and verifying the self-consistency by correlating the experimental solubility values with a semi-empirical model as a function of temperature, pressure and pure carbon dioxide density.

Effect of graphite target power density on tribological properties of graphite-like carbon films

Science.gov (United States)

Dong, Dan; Jiang, Bailing; Li, Hongtao; Du, Yuzhou; Yang, Chao

2018-05-01

In order to improve the tribological performance, a series of graphite-like carbon (GLC) films with different graphite target power densities were prepared by magnetron sputtering. The valence bond and microstructure of films were characterized by AFM, TEM, XPS and Raman spectra. The variation of mechanical and tribological properties with graphite target power density was analyzed. The results showed that with the increase of graphite target power density, the deposition rate and the ratio of sp2 bond increased obviously. The hardness firstly increased and then decreased with the increase of graphite target power density, whilst the friction coefficient and the specific wear rate increased slightly after a decrease with the increasing graphite target power density. The friction coefficient and the specific wear rate were the lowest when the graphite target power density was 23.3 W/cm2.

Carbon 14 dating method

International Nuclear Information System (INIS)

Fortin, Ph.

2000-01-01

This document gives a first introduction to 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 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 14 C dates; the preparation of samples; the benzene synthesis; the current applications of the method. (J.S.)

Radioactivity measurement of barium carbonate [14C] by liquid scintillation counting

International Nuclear Information System (INIS)

Kobayashi, Katsutoshi; Hoizumi, Kiyoshi

1985-03-01

Two methods of sample preparation for the measurement of specific activity of BaCO 3 [ 14 C] by external standard method in liquid scintillation counting were studied. BaCO 3 [ 14 C] was decomposed by perchloric acid solution and generated CO 2 [ 14 C] was absorbed by ethylene glycol monomethyl ether solution of monoethanolamine as the method 1 or aqueous sodium hydroxide as the method 2. In order to prepare the sample solution of adequate radioactivity concentration, these carbonate solutions by the methods 1 and 2 were diluted with the suitable organic solvent and distilled water respectively. One tenth millilitre of these sample solutions was added into 10 ml of PPO-toluene scintillator containing 0.1 ml of monoethanolamine in a counting vial and homogeneously dissolved with ethyl alcohol. The results of the radioactivity measurement of BaCO 3 [ 14 C] based on the different method agreed within 5 % and the counting rate was found to be stable for as long as 7 deays or more. Both methods of preparation are suitable for the routine measurement because of their simplicity and feasibility. In the case of method 2, the liquid radioactive waste is almost inorganic solution and recovery in the form of BaCO 3 [ 14 C] is easily performed, so that this method is very advantageous from the view point of the radioactive waste treatement. (author)

Dating of archaeological objects using Carbon-14 facilities

International Nuclear Information System (INIS)

Kamisah Hj Alias; Noraishah Othman; Nasasni Nasrol

2004-01-01

Dating is the key to organising all archaeological evidence. Furthermore, the development of dating methods, whether traditional or scientific, illustrates the ingenuity and lateral thinking that make archaeological problem-solving such a fascinating exercise. The development of MINT radiocarbon dating procedures is reviewed. Basic principles and counting techniques are discussed. A sample is converted by chemical methods into a suitable form, such as carbon dioxide followed by the acetylene gas, and the benzene end-product is placed inside a proportional counter to measure the radioactivity of 14 C. Not until some years ago did absolute dates by radiocarbon dating become a reality for prehistoric archaeology in Malaysia where thermoluminescence and fission-track dating had begun to provide a locally applicable dating method some decades earlier. Applications of radiocarbon dating procedures in the fields of archaeology are also discussed. (Author)

Application of Alkenone 14C-Based chronostratigraphy in carbonate barren sediments on the Peru Margin.

Science.gov (United States)

Higginson, M. J.; Altabet, M. A.; Herbert, T. D.

2003-04-01

Despite the availability of high-quality sediment cores in key locations, little paleoclimatic information exists for the Peru margin largely because poor carbonate preservation severely restricts the use of traditional carbonate-based proxies for stratigraphy, dating, and paleo-environmental reconstruction. Many sites also include hiatuses produced by the variable influence of undercurrents on sediment accumulation. To overcome these difficulties, we have developed (in collaboration with T. Eglinton, WHOI) a laboratory facility to successfully extract and purify haptophyte-derived alkenones for compound specific 14C AMS dating (modified from OHKOUCHI et al., 2002). This avoids potential problems with dating bulk organic carbon which we assume, even in an upwelling environment as highly productive as the Peru margin, is not a priori solely of marine origin. In a recently collected, mid-Peru Margin core (ODP Leg 201 Site 1228D), comparison of our alkenone 14C dates with bulk sediment organic carbon dates and known stratigraphic markers produces a very well constrained, curvilinear age-depth relationship for at least the last 14 Kyr. A discrete ash layer at Site 1228D with an adjacent alkenone 14C age of 3890 ± 350 yr, is within error identical to the 14C age of a prominent ash layer (3800 ± 50 yr) found west of the large Peruvian El Misti volcano (16^o18'S, 71^o24'W). In summary, these results show that the Peru margin alkenones are autochthonous (i.e. not from an older, distant source) and provide sufficient dating precision to permit, for the first time, high-resolution paleoceanographic studies in this highly important marine province. Based upon this new chronology, synchronous changes in alkenone-derived SST estimates in two of our independently-dated records are the first to record at high-resolution (a) a large LGM-Holocene SST range in the Tropics (up to 7.8 ^oC during brief events in this upwelling location); and (b) sharp coolings (4 ^oC) consistent with

Development of Carbon-14 Waste Destruction and Recovery System Using AC Plasma Torch Technology Final Report CRADA No. TC02108.0

Energy Technology Data Exchange (ETDEWEB)

Althouse, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McKannay, R. H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-08-15

This was a collaborative effort between Lawrence Livermore National Security, LLC as manager and operator of Lawrence Livermore National Laboratory (LLNL) and ISOFLEX USA (ISOFLEX), to 1) develop and test a prototype waste destruction system ("System") using AC plasma torch technology to break down and drastically reduce the volume of Carbon-14 (C-14) contaminated medical laboratory wastes while satisfying all environmental regulations, and 2) develop and demonstrate methods for recovering 99%+ of the carbon including the C-14 allowing for possible re-use as a tagging and labeling tool in the biomedical industry.

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

International Nuclear Information System (INIS)

Kannan, R.

2009-01-01

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

Biogenesis of tritiated and carbon-14 methane from low-level radioactive waste

International Nuclear Information System (INIS)

Francis, A.J.; Dobbs, S.; Doering, R.F.

1980-01-01

Methane bacteria were detected in leachate samples collected from commercial low-level radioactive waste disposal sites. Significant amounts of tritiated and carbon-14 methane were generated by a mixed methanogenic culture from a leachate sample collected from the low-level radioactive waste disposal site, Maxey Flats, KY. Tritiated methane was produced by methane bacteria from synthetic media containing 2 mCi of tritium as tritiated water or tritiated acetate, and the level of tritium added to the medium had no effect on methanogenesis. Under anaerobic conditions the organic compounds containing 14 C and 3 H activity and tritiated water in the waste are metabolized by microorganisms and they produce radioactive gases which escape into the environment from the disposal sites. 4 figures, 3 tables

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

International Nuclear Information System (INIS)

Bird, G.A.

1996-09-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Bird, G.A. [AECL, Pinawa, MB (Canada). Whiteshell Labs.] [and others

1996-09-01

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

J-type Carbon Stars: A Dominant Source of {sup 14}N-rich Presolar SiC Grains of Type AB

Energy Technology Data Exchange (ETDEWEB)

Liu, Nan; Nittler, Larry R.; Alexander, Conel M. O’D.; Wang, Jianhua [Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015 (United States); Stephan, Thomas; Boehnke, Patrick; Davis, Andrew M.; Trappitsch, Reto; Pellin, Michael J., E-mail: nliu@carnegiescience.edu [Department of the Geophysical Sciences, The University of Chicago, Chicago, IL 60637 (United States)

2017-07-20

We report Mo isotopic data of 27 new presolar SiC grains, including 12 {sup 14}N-rich AB ({sup 14}N/{sup 15}N > 440, AB2) and 15 mainstream (MS) grains, and their correlated Sr and Ba isotope ratios when available. Direct comparison of the data for the MS grains, which came from low-mass asymptotic giant branch (AGB) stars with large s -process isotope enhancements, with the AB2 grain data demonstrates that AB2 grains show near-solar isotopic compositions and lack s -process enhancements. The near-normal Sr, Mo, and Ba isotopic compositions of AB2 grains clearly exclude born-again AGB stars, where the intermediate neutron-capture process ( i -process) takes place, as their stellar source. On the other hand, low-mass CO novae and early R- and J-type carbon stars show {sup 13}C and {sup 14}N excesses but no s -process enhancements and are thus potential stellar sources of AB2 grains. Because both early R-type carbon stars and CO novae are rare objects, the abundant J-type carbon stars (10%–15% of all carbon stars) are thus likely to be a dominant source of AB2 grains.

Simultaneous detection of multiple DNA targets by integrating dual-color graphene quantum dot nanoprobes and carbon nanotubes.

Science.gov (United States)

Qian, Zhaosheng; Shan, Xiaoyue; Chai, Lujing; Chen, Jianrong; Feng, Hui

2014-12-01

Simultaneous detection of multiple DNA targets was achieved based on a biocompatible graphene quantum dots (GQDs) and carbon nanotubes (CNTs) platform through spontaneous assembly between dual-color GQD-based probes and CNTs and subsequently self-recognition between DNA probes and targets. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An update on anticancer drug development and delivery targeting carbonic anhydrase IX

Directory of Open Access Journals (Sweden)

Justina Kazokaitė

2017-11-01

Full Text Available The expression of carbonic anhydrase (CA IX is up-regulated in many types of solid tumors in humans under hypoxic and acidic microenvironment. Inhibition of CA IX enzymatic activity with selective inhibitors, antibodies or labeled probes has been shown to reverse the acidic environment of solid tumors and reduce the tumor growth establishing the significant role of CA IX in tumorigenesis. Thus, the development of potent antitumor drugs targeting CA IX with minimal toxic effects is important for the target-specific tumor therapy. Recently, several promising antitumor agents against CA IX have been developed to treat certain types of cancers in combination with radiation and chemotherapy. Here we review the inhibition of CA IX by small molecule compounds and monoclonal antibodies. The methods of enzymatic assays, biophysical methods, animal models including zebrafish and Xenopus oocytes, and techniques of diagnostic imaging to detect hypoxic tumors using CA IX-targeted conjugates are discussed with the aim to overview the recent progress related to novel therapeutic agents that target CA IX in hypoxic tumors.

Using the Nova target chamber for high-yield targets

International Nuclear Information System (INIS)

Pitts, J.H.

1987-01-01

The existing 2.2-m-radius Nova aluminum target chamber, coated and lined with boron-seeded carbon shields, is proposed for use with 1000-MJ-yield targets in the next laser facility. The laser beam and diagnostic holes in the target chamber are left open and the desired 10 -2 Torr vacuum is maintained both inside and outside the target chamber; a larger target chamber room is the vacuum barrier to the atmosphere. The hole area available is three times that necessary to maintain a maximum fluence below 12 J/cm 2 on optics placed at a radius of 10 m. Maximum stress in the target chamber wall is 73 MPa, which complies with the intent of the ASME Pressure Vessel Code. However, shock waves passing through the inner carbon shield could cause it to comminute. We propose tests and analyses to ensure that the inner carbon shield survives the environment. 13 refs

Density distribution of {sup 14}Be from reaction cross-section measurements

Energy Technology Data Exchange (ETDEWEB)

Moriguchi, T. [Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Ozawa, A., E-mail: ozawa@tac.tsukuba.ac.jp [Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Ishimoto, S. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Abe, Y. [Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Fukuda, M. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Hachiuma, I. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Ishibashi, Y.; Ito, Y. [Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Kuboki, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Lantz, M. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Nagae, D. [Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Namihira, K. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Nishimura, D. [Department of Physics, Osaka University, Osaka 560-0043 (Japan); Ohtsubo, T. [Department of Physics, Niigata University, Niigata 950-2181 (Japan); Ooishi, H. [Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Suda, T. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Suzuki, H. [Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Suzuki, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Takechi, M.; Tanaka, K. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); and others

2014-09-15

We measured the reaction cross sections of the two-neutron halo nucleus {sup 14}Be with proton and carbon targets at about 41 and 76 MeV/nucleon. Based on a Glauber model calculation, we deduced the matter density distribution of {sup 14}Be in which previously measured interaction cross sections at relativistic energies were also included. An s-wave dominance in {sup 14}Be has been confirmed, although the halo tail of {sup 14}Be is not distributed as much as that of {sup 11}Li. Significant mixing of the p-wave in addition to the s- and d-wave is also suggested.

Designer policy for carbon and biodiversity co-benefits under global change

Science.gov (United States)

Bryan, Brett A.; Runting, Rebecca K.; Capon, Tim; Perring, Michael P.; Cunningham, Shaun C.; Kragt, Marit E.; Nolan, Martin; Law, Elizabeth A.; Renwick, Anna R.; Eber, Sue; Christian, Rochelle; Wilson, Kerrie A.

2016-03-01

Carbon payments can help mitigate both climate change and biodiversity decline through the reforestation of agricultural land. However, to achieve biodiversity co-benefits, carbon payments often require support from other policy mechanisms such as regulation, targeting, and complementary incentives. We evaluated 14 policy mechanisms for supplying carbon and biodiversity co-benefits through reforestation of carbon plantings (CP) and environmental plantings (EP) in Australia’s 85.3 Mha agricultural land under global change. The reference policy--uniform payments (bidders are paid the same price) with land-use competition (both CP and EP eligible for payments), targeting carbon--achieved significant carbon sequestration but negligible biodiversity co-benefits. Land-use regulation (only EP eligible) and two additional incentives complementing the reference policy (biodiversity premium, carbon levy) increased biodiversity co-benefits, but mostly inefficiently. Discriminatory payments (bidders are paid their bid price) with land-use competition were efficient, and with multifunctional targeting of both carbon and biodiversity co-benefits increased the biodiversity co-benefits almost 100-fold. Our findings were robust to uncertainty in global outlook, and to key agricultural productivity and land-use adoption assumptions. The results suggest clear policy directions, but careful mechanism design will be key to realising these efficiencies in practice. Choices remain for society about the amount of carbon and biodiversity co-benefits desired, and the price it is prepared to pay for them.

J-type Carbon Stars: A Dominant Source of ¹⁴ N-rich Presolar SiC Grains of Type AB

Energy Technology Data Exchange (ETDEWEB)

Liu, Nan; Stephan, Thomas; Boehnke, Patrick; Nittler, Larry R.; Alexander, Conel M. O’D.; Wang, Jianhua; Davis, Andrew M.; Trappitsch, Reto; Pellin, Michael J.

2017-07-20

We report Mo isotopic data of 27 new presolar SiC grains, including 12 N-14-rich AB (N-14/N-15 > 440, AB2) and 15 mainstream (MS) grains, and their correlated Sr and Ba isotope ratios when available. Direct comparison of the data for the MS grains, which came from low-mass asymptotic giant branch (AGB) stars with large s-process isotope enhancements, with the AB2 grain data demonstrates that AB2 grains show near-solar isotopic compositions and lack s-process enhancements. The near-normal Sr, Mo, and Ba isotopic compositions of AB2 grains clearly exclude born-again AGB stars, where the intermediate neutron-capture process (i-process) takes place, as their stellar source. On the other hand, low-mass CO novae and early R-and J-type carbon stars show C-13 and N-14 excesses but no s-process enhancements and are thus potential stellar sources of AB2 grains. Because both early R-type carbon stars and CO novae are rare objects, the abundant J-type carbon stars (10%-15% of all carbon stars) are thus likely to be a dominant source of AB2 grains.

Carbonates in leaching reactions in context of {sup 14}C dating

Energy Technology Data Exchange (ETDEWEB)

Michalska, Danuta, E-mail: danamich@amu.edu.pl [Institute of Geology, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, ul. Makow Polnych 16, 61-606 Poznan (Poland); Czernik, Justyna, E-mail: justyna.czernik@gmail.com [Poznań Radiocarbon Laboratory, ul. Rubież 46, 61-612 Poznań (Poland)

2015-10-15

Lime mortars as a mixture of binder and aggregate may contain carbon of various origins. If the mortars are made of totally burnt lime, radiocarbon dating of binder yields the real age of building construction. The presence of carbonaceous aggregate has a significant influence on the {sup 14}C measurements results and depending on the type of aggregate and fraction they may cause overaging. Another problem, especially in case of hydraulic mortars that continue to be chemically active for a very long time, is the recrystallization usually connected with rejuvenation of the results but also, depending on local geological structures, with so called reservoir effect yielding apparent ages. An attempt in separating the binder from other carbonaceous components successfully was made for samples from Israel by Nawrocka-Michalska et al. (2007). The same preparation procedure, after taking into account the petrographic composition, was used for samples coming from Poland, Nawrocka et al. (2009). To verify the procedure used previously for non-hydraulic samples determination an experimental tests on carbonaceous mortars with crushed bricks from Novae in Bulgaria were made. Additionally, to identify different carbonaceous structures and their morphology, a cathodoluminescence and scanning electron microscope with electron dispersive spectrometer were applied. The crushed bricks and brick dust used in mortars production process have been interpreted as an alternative use to other pozzolanic materials. The reaction between lime and pozzolanic additives take place easily and affects the rate and course of carbonates decomposition in orthophosphric acid, during the samples pretreatment for dating. The composition of the Bulgarian samples together with influence of climate conditions on mortar carbonates do not allow for making straightforward conclusions in chronology context, but gives some new guidelines in terms of hydraulic mortars application for dating. This work has mainly

Carbonates in leaching reactions in context of "1"4C dating

International Nuclear Information System (INIS)

Michalska, Danuta; Czernik, Justyna

2015-01-01

Lime mortars as a mixture of binder and aggregate may contain carbon of various origins. If the mortars are made of totally burnt lime, radiocarbon dating of binder yields the real age of building construction. The presence of carbonaceous aggregate has a significant influence on the "1"4C measurements results and depending on the type of aggregate and fraction they may cause overaging. Another problem, especially in case of hydraulic mortars that continue to be chemically active for a very long time, is the recrystallization usually connected with rejuvenation of the results but also, depending on local geological structures, with so called reservoir effect yielding apparent ages. An attempt in separating the binder from other carbonaceous components successfully was made for samples from Israel by Nawrocka-Michalska et al. (2007). The same preparation procedure, after taking into account the petrographic composition, was used for samples coming from Poland, Nawrocka et al. (2009). To verify the procedure used previously for non-hydraulic samples determination an experimental tests on carbonaceous mortars with crushed bricks from Novae in Bulgaria were made. Additionally, to identify different carbonaceous structures and their morphology, a cathodoluminescence and scanning electron microscope with electron dispersive spectrometer were applied. The crushed bricks and brick dust used in mortars production process have been interpreted as an alternative use to other pozzolanic materials. The reaction between lime and pozzolanic additives take place easily and affects the rate and course of carbonates decomposition in orthophosphric acid, during the samples pretreatment for dating. The composition of the Bulgarian samples together with influence of climate conditions on mortar carbonates do not allow for making straightforward conclusions in chronology context, but gives some new guidelines in terms of hydraulic mortars application for dating. This work has mainly

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

Science.gov (United States)

Sonnleitner, Elisabeth; Valentini, Martina; Wenner, Nicolas; Haichar, Feth el Zahar; Haas, Dieter; Lapouge, Karine

2012-01-01

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.

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

International Nuclear Information System (INIS)

Lu, Ning; Ross, B.

1993-01-01

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

Giant Negative Piezoresistive Effect in Diamond-like Carbon and Diamond-like Carbon-Based Nickel Nanocomposite Films Deposited by Reactive Magnetron Sputtering of Ni Target

DEFF Research Database (Denmark)

Meškinis, Šaru Nas; Gudaitis, Rimantas; Šlapikas, Kęstutis

2018-01-01

deposited by either reactive HIPIMS or dc magnetron sputtering of Ni target was explained by possible clustering of the sp2-bonded carbon and/or formation of areas with the decreased hydrogen content. It was suggested that the tensile stress-induced rearrangements of these conglomerations have resulted......Piezoresistive properties of hydrogenated diamond-like carbon (DLC) and DLC-based nickel nanocomposite (DLC:Ni) films were studied in the range of low concentration of nickel nanoparticles. The films were deposited by reactive high power pulsed magnetron sputtering (HIPIMS) of Ni target, and some...... samples were deposited by direct current (dc) reactive magnetron sputtering for comparison purposes. Raman scattering spectroscopy, energy-dispersive X-ray spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS) were used to study the structure and chemical composition of the films. A four...

Production of an accelerated oxygen-14 beam

International Nuclear Information System (INIS)

Powell, J.; O'Neil, J.P.; Cerny, Joseph

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 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 been built and is operational, and initial tests of accelerating an oxygen-14 beam have been performed

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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.

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

International Nuclear Information System (INIS)

Tiew, B.J.; Shuhaimi, M.; Hashim, H.

2012-01-01

Highlights: ► CO 2 emissions reduction targeting for existing plant were categorized into three groups. ► Model for CO 2 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 CO 2 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 CO 2 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 CO 2 emissions reduction at minimum payback period.

Ultra-hard AlMgB14 coatings fabricated by RF magnetron sputtering from a stoichiometric target

Science.gov (United States)

Grishin, A. M.; Khartsev, S. I.; Böhlmark, J.; Ahlgren, M.

2015-01-01

For the first time hard aluminum magnesium boride films were fabricated by RF magnetron sputtering from a single stoichiometric ceramic AlMgB14 target. Optimized processing conditions (substrate temperature, target sputtering power and target-to-substrate distance) enable fabrication of stoichiometric in-depth compositionally homogeneous films with the peak values of nanohardness 88 GPa and Young's modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 and 275 GPa at 200 nm depth in 2 μm thick film.

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...... by microwave heating to afford [1-C-14]levulinic acid. Subsequently, bromination and oxidation gave the targeted furan-2-one with a radiochemical purity of > 97% and a specific activity of 57 mCi/mmol....

The PTPN14 Tumor Suppressor Is a Degradation Target of Human Papillomavirus E7.

Science.gov (United States)

Szalmás, Anita; Tomaić, Vjekoslav; Basukala, Om; Massimi, Paola; Mittal, Suruchi; Kónya, József; Banks, Lawrence

2017-04-01

Activation of signaling pathways ensuring cell growth is essential for the proliferative competence of human papillomavirus (HPV)-infected cells. Tyrosine kinases and phosphatases are key regulators of cellular growth control pathways. A recently identified potential cellular target of HPV E7 is the cytoplasmic protein tyrosine phosphatase PTPN14, which is a potential tumor suppressor and is linked to the control of the Hippo and Wnt/beta-catenin signaling pathways. In this study, we show that the E7 proteins of both high-risk and low-risk mucosal HPV types can interact with PTPN14. This interaction is independent of retinoblastoma protein (pRb) and involves residues in the carboxy-terminal region of E7. We also show that high-risk E7 induces proteasome-mediated degradation of PTPN14 in cells derived from cervical tumors. This degradation appears to be independent of cullin-1 or cullin-2 but most likely involves the UBR4/p600 ubiquitin ligase. The degree to which E7 downregulates PTPN14 would suggest that this interaction is important for the viral life cycle and potentially also for the development of malignancy. In support of this we find that overexpression of PTPN14 decreases the ability of HPV-16 E7 to cooperate with activated EJ-ras in primary cell transformation assays. IMPORTANCE This study links HPV E7 to the deregulation of protein tyrosine phosphatase signaling pathways. PTPN14 is classified as a potential tumor suppressor protein, and here we show that it is very susceptible to HPV E7-induced proteasome-mediated degradation. Intriguingly, this appears to use a mechanism that is different from that employed by E7 to target pRb. Therefore, this study has important implications for our understanding of the molecular basis for E7 function and also sheds important light on the potential role of PTPN14 as a tumor suppressor. Copyright © 2017 American Society for Microbiology.

Kinetics of extracellular release of 14C-labelled organic carbon by submerged macrophytes

International Nuclear Information System (INIS)

Soendergaard, M.

1981-01-01

The release of extracellular organic carbon (EOC) by six submerged freswater macrophytes was measured in time course studies with a 14 C-technique. Incubation in light in an open water-flow system made it possible to assay the time courses of 14 C-fixation and the simultaneous release of labelled EOC. Heterotrophic utilization of the released products by epiphytic communities was measured. Two patterns of release kinetics were found: (1) Constant rates of release occurred during the incubations, (2) The rates still increased after 24 h of incubation. During the first hours of incubation the rates of release increased in all species. Elodea reached constant rates after 2-4 h and Littorella and Ceratophyllum demersum after about 20 h. In the experiments with C. submersum and Nitella the rates of release increased almost linearly during the entire incubation period. The kinetics of release were in agreement with the molecular weight distribution of the dissolved EOC measured with gel chromatography. Low molecular weight products ( 10000 Daltons) dominated the dissolved EOC released by C. submersum and Nitella. A large fraction (18-60%) of the total EOC could be recovered on filters with a pore size of 0.2 μm. This particulate fraction probably represents some abiotic removal. The quantities of relase were low in all species and did not exceed 0.9% of the photosynthetic carbon fixation. Heterotrophic uptake by the epiphytic communities was less than 10% of the EOC released. The results emphasize that the 14 C-labelling of extracellular products is a time dependent process. (author)

Margin estimation and disturbances of irradiation field in layer-stacking carbon-ion beams for respiratory moving targets.

Science.gov (United States)

Tajiri, Shinya; Tashiro, Mutsumi; Mizukami, Tomohiro; Tsukishima, Chihiro; Torikoshi, Masami; Kanai, Tatsuaki

2017-11-01

Carbon-ion therapy by layer-stacking irradiation for static targets has been practised in clinical treatments. In order to apply this technique to a moving target, disturbances of carbon-ion dose distributions due to respiratory motion have been studied based on the measurement using a respiratory motion phantom, and the margin estimation given by the square root of the summation Internal margin2+Setup margin2 has been assessed. We assessed the volume in which the variation in the ratio of the dose for a target moving due to respiration relative to the dose for a static target was within 5%. The margins were insufficient for use with layer-stacking irradiation of a moving target, and an additional margin was required. The lateral movement of a target converts to the range variation, as the thickness of the range compensator changes with the movement of the target. Although the additional margin changes according to the shape of the ridge filter, dose uniformity of 5% can be achieved for a spherical target 93 mm in diameter when the upward range variation is limited to 5 mm and the additional margin of 2.5 mm is applied in case of our ridge filter. Dose uniformity in a clinical target largely depends on the shape of the mini-peak as well as on the bolus shape. We have shown the relationship between range variation and dose uniformity. In actual therapy, the upper limit of target movement should be considered by assessing the bolus shape. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

The air quality and health co-benefits of alternative post-2020 pathways for achieving peak carbon targets in Jiangsu, China

Science.gov (United States)

Liu, M.; Bi, J.; Huang, Y.; Kinney, P. L.

2016-12-01

Jiangsu, which has three national low-carbon pilot cities, is set to be a model province in China for achieving peak carbon targets before 2030. However, according to local planning of responding to climate change, carbon emissions are projected to keep going up before 2020 even the strictest measures are implemented. In other words, innovative measures must be in action after 2020. This work aimed at assessing the air quality and health co-benefits of alternative post-2020 measures to help remove barriers of policy implementation through tying it to local incentives for air quality improvement. To achieve the aim, we select 2010 as baseline year and develop Bussiness As Usual (BAU) and Traditional Carbon Reduction (TCR) scenarios before 2020. Under BAU, only existing climate and air pollution control policies are considered; under TCR, potential climate policies in local planning and existing air pollution control policies are considered. After 2020, integrated gasification combined cycle (IGCC) plant with carbon capture and storage (CCS) technology and large-scale substitution of renewable energy seem to be two promising pathways for achieving peak carbon targets. Therefore, two additional scenarios (TCR-IGCC and TCR-SRE) are set after 2020. Based on the projections of future energy balances and industrial productions, we estimate the pollutant emissions and simulate PM2.5 and ozone concentrations by 2017, 2020, 2030 and 2050 using CMAQ. Then using health impact assessment approach, the premature deaths are estimated and monetized. Results show that the carbon peak in Jiangsu will be achieved before 2030 only under TCR-IGCC and TCR-SRE scenarios. Under three policy scenarios, Jiangsu's carbon emission control targets would have substantial effects on primary air pollutant emissions far beyond those we estimate would be needed to meet the PM2.5 concentration targets in 2017. Compared with IGCC with CCS, large-scale substitutions of renewable energy bring

Sampling and monitoring of carbon-14 in gaseous effluents from nuclear facilities - a literature survey

International Nuclear Information System (INIS)

Snellman, M.

1988-12-01

C-14 compounds produced in the coolant may be released mainly together with off-gas and waste water from the coolant purification and treatment system. In reactors the release of C-14 will occur mainly in gaseous effluents and only a few percent in liquid effluents. Reported releases from BWRs range from 260 to 670 GBq/GW(e) x year and from 90 to 430 GBq/GW(e) x year for PWRs. At BWRs the condenser air ejector contributes the main inplant release pathway, whereas in PWRs the off-gas treatment vents are the main pathway for C-14 release. C-14 sampling methods depend generally on the C-14 being in the form of CO 2 . The off-gas discharges from BWRs are mainly in the form of CO 2 whereas in PWRs a major fraction of the released C-14 is in the form of hydrocarbons or carbon monoxide (generally 80-100%). Sampling systems in PWRs should therefore be equipped with a catalytic oxidizer to convert all C-14 to CO 2 before trapping. The purpose of this study is to provide information on the techniques available for sampling and monitoring C-14

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

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...... 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......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...

Requirements for controlling a repository's releases of carbon-14 dioxide; the high costs and negligible benefits

International Nuclear Information System (INIS)

Park, U Sun; Pflum, C.G.

1990-01-01

A repository excavated within the unsaturated zone may release carbon (C)-14 dioxide in amounts that exceed limits imposed by the Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission (NRC). The release would not threaten the general population, but may expose some hypothetical maximally exposed individual to 0.0005 millirems/year. Yet a repository's releases of C-14 dioxide are strictly regulated, perhaps unintentionally. The EPA and NRC regulations could force the Department of Energy to design and fabricate an expensive 10,000-year waste package solely for the sake of controlling releases of C-14 dioxide. This paper argues that the repository regulations should exempt releases of C-14 dioxide or at least impose more equitable limits. 21 refs., 1 tab

Radiocarbon (14C) Constraints On The Fraction Of Refractory Dissolved Organic Carbon In Primary Marine Aerosol From The Northwest Atlantic

Science.gov (United States)

Beaupre, S. R.; Kieber, D. J.; Keene, W. C.; Long, M. S.; Frossard, A. A.; Kinsey, J. D.; Duplessis, P.; Chang, R.; Maben, J. R.; Lu, X.; Zhu, Y.; Bisgrove, J.

2017-12-01

Nearly all organic carbon in seawater is dissolved (DOC), with more than 95% considered refractory based on modeled average lifetimes ( 16,000 years) and characteristically old bulk radiocarbon (14C) ages (4000 - 6000 years) that exceed the timescales of overturning circulation. Although this refractory dissolved organic carbon (RDOC) is present throughout the oceans as a major reservoir of the global carbon cycle, its sources and sinks are poorly constrained. Recently, RDOC was proposed to be removed from the oceans through adsorption onto the surfaces of rising bubble plumes produced by breaking waves, ejection into the atmosphere via bubble bursting as a component of primary marine aerosol (PMA), and subsequent oxidation in the atmosphere. To test this mechanism, we used natural abundance 14C (5730 ± 40 yr half-life) to trace the fraction of RDOC in PMA produced in a high capacity generator at two biologically-productive and two oligotrophic hydrographic stations in the Northwest Atlantic Ocean during a research cruise aboard the R/V Endeavor (Sep - Oct 2016). The 14C signatures of PMA separately generated day and night from near-surface (5 m) and deep (2500 m) seawater were compared with corresponding 14C signatures in seawater of near-surface dissolved inorganic carbon (DIC, a proxy for recently produced organic matter), bulk deep DOC (a proxy for RDOC), and near-surface bulk DOC. Results constrain the selectivity of PMA formation from RDOC in natural mixtures of recently produced and refractory DOC. The implications of these results for PMA formation and RDOC biogeochemistry will be discussed.

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

International Nuclear Information System (INIS)

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 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 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 2 fertilization and impose a constraint on the ultimate total carbon mass in the biosphere

Proton induced target fragmentation studies on solid state nuclear track detectors using Carbon radiators

Science.gov (United States)

Szabó, J.; Pálfalvi, J. K.; Strádi, A.; Bilski, P.; Swakoń, J.; Stolarczyk, L.

2018-04-01

One of the limiting factors of an astronaut's career is the dose received from space radiation. High energy protons, being the main components of the complex radiation field present on a spacecraft, give a significant contribution to the dose. To investigate the behavior of solid state nuclear track detectors (SSNTDs) if they are irradiated by such particles, SSNTD stacks containing carbon blocks were exposed to high energy proton beams (70, 100, 150 and 230 MeV) at the Proteus cyclotron, IFJ PAN -Krakow. The incident protons cannot be detected directly; however, tracks of secondary particles, recoils and fragments of the constituent atoms of the detector material and of the carbon radiator are formed. It was found that as the proton energy increases, the number of tracks induced in the PADC material by secondary particles decreases. From the measured geometrical parameters of the tracks the linear energy transfer (LET) spectrum and the dosimetric quantities were determined, applying appropriate calibration. In the LET spectra the LET range of the most important secondary particles could be identified and their abundance showed differences in the spectra if the detectors were short or long etched. The LET spectra obtained on the SSNTDs irradiated by protons were compared to LET spectra of detectors flown on the International Space Station (ISS): they were quite similar, resulting in a quality factor difference of only 5%. Thermoluminescent detectors (TLDs) were applied in each case to measure the dose from primary protons and other lower LET particles present in space. Comparing and analyzing the results of the TLD and SSNTD measurements, it was obtained that proton induced target fragments contributed to the total absorbed dose in 3.2% and to the dose equivalent in 14.2% in this particular space experiment.

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...

The leachability of carbon-14-labelled 3,4-benzopyrene from coal ash into aqueous systems

NARCIS (Netherlands)

Besemer, A.C.; Kanij, J.

1984-01-01

The leachability of polycyclic aromatic hydrocarbons from coal ash into aqueous systems was studied. Carbon-14-labeled 3,4-Benzopyrene (BaP) was deposited on coal fly ash by adsorption from the liquid phase in quantities of about 10 ??g/g ash. After a thermal treatment in air at 120??C for 2 hours

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

International Nuclear Information System (INIS)

Lindroos, Alf; Ranta, Heikki; 14C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark))" data-affiliation=" (AMS 14C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark))" >Heinemeier, Jan; Lill, Jan-Olof

2014-01-01

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 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 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 14 C age of the lime lumps of this particular church is an important contribution to the discussion on stone church chronology in Scandinavia

Hot target assembly at 14 UD Pelletron Accelerator Facility, BARC- TIFR, Mumbai

International Nuclear Information System (INIS)

Sharma, S.C.; Ramjilal; Ninawe, N.G.; Bhagwat, P.V.; Ahmeabadhai, P.; Kain, V.

2005-01-01

BARC-TIFR 14 UD Pelletron Accelerator Facility at Mumbai is operational since 1989 with progressively increased efficiency. The accelerator has been serving as major facility for heavy ion based research in India. There is an increased demand for high current proton beam, especially on heated targets for reactor physics based experiments. A proton beam setup is commissioned in the tower area of the existing facility itself, which provide proton beam of energy 2 MeV to 26 MeV with maximum 3 μA current. This setup is being used to produce radioisotopes and tracer packets. Proton beam of few MeV in μA current range is also needed to study radiation effects on metals at higher temperature, for use in reactors. For this purpose a hot target assembly has been designed and is being currently used at the Pelletron Accelerator

Carbon-14 isotope effects in the addition of 2,4-dinitrobenzenesulfenyl chloride to styrene-1-14C and styrene-2-14C

International Nuclear Information System (INIS)

Kanska, M.; Fry, A.

1982-01-01

The carbon-isotope effect reported here represents the first step in a general study of the mechanisms of simple electrophilic addition reactions by isotope effect techniques using the successive labeling approach. The addition of 2,4-dinitrobenzenesulfenyl chloride to styrene was chosen as a ''calibration case'' for the cyclic mechanism. The observed isotope effects at /sup α/C and /sup #betta#/C are fully consistent with the cyclic mechanism and probably inconsistent with the open carbenium ion mechanisms. The values of 12 k/ 14 k indicated in this report are averages (and standard deviations) of values for five different fractions of reaction ranging from 20% to 70% with the calculations being made by all four of the Tong and Yankwich equations for each fraction of reaction. Results indicated that there were no trends in the 12 k/ 14 k values as the fraction of reaction varied, and as can be seen by the low standard deviations, there was good agreement among the values calculated by the four equations. These two facts to indicate that the starting materials were of high chemical and radiochemical purity and that the procedures used in the isotope effect experiments were accurate and properly controlled

Gases and carbon in metals. Pt. 14

International Nuclear Information System (INIS)

Jehn, H.; Speck, H.; Hehn, W.; Fromm, E.; Hoerz, G.

1981-01-01

This issue is part of a series of data on 'Gases and Carbon in Metals' which supplements the data compilation in the book 'Gase und Kohlenstoff in Metallen' (Gases and Carbon in Metals), edited by E. Fromm and E. Gebhardt, Springer-Verlag, Berlin 1976. The present survey includes results from papers published after the copy deadline and recommends critically selected data. Furthermore, it comprises a bibliography of relevant literature. For each element, firstly data on binary systems are presented, starting with hydrogen and followed by carbon, nitrogen, oxygen, and rare gases. Within one metal-metalloid system the data are listed under topics such as solubility, solubility limit, dissociation pressure of compounds, vapour pressure of volatile oxides, thermodynamic data, diffusion, transport parameters (effective valence, heat of transport), permeation of gases through metals, gas absorption and gas desorption kinetics, compound formation kinetics, precipitation kinetics, and property changes. Following the data on binary systems, the data of ternary systems are presented, beginning with systems which contain one metal and two gases or one gas and carbon and continuing with systems with two metals and one gas or carbon. (orig./GE)

Determination of the carbon content of domestic farm produces to estimate offsite C-14 ingestion dose

International Nuclear Information System (INIS)

Jung, Y. G.; Kim, M. J.; Lee, G. B.

2003-01-01

The carbon content of grains, leafy and root vegetables, and fruits which the Koreans usually eat were calculated to use in the estimation of offsite C-14 ingestion dose. With the data of food intake per day in the Report on 1998 national health and nutrition survey- dietary intake survey, 5 age-group integrate d intake of the 4 farm produce groups were extracted for food items and the amount. Intake percentage in each food group were taken as food weighing factor for the foods. Carbon content was calculated using protein, fat, and carbohydrate content of the foods, and multiplied by the corresponding food weighing factor to derive the content of the food groups. The calculated carbon content of grains, leafy and root vegetables, and fruits were 39.%, 4.2%, 8.0%, and 5.9% respectively. Grains and fruits were not much different from ODCM for carbon content, but vegetables were higher by 0.7%∼4.5%

The evolution of carbon-14 and tritium containing gases in a radioactive waste repository

International Nuclear Information System (INIS)

Jefferies, N.L.

1990-04-01

The principal processes which well lead to the formation of gases in a repository containing low- and intermediate-level radioactive waste have been identified as corrosion, microbiological activity and radiolysis. The largest contribution to gas production is from hydrogen, generated from anaerobic corrosion of metallic components of the waste. Substitution of the active isotopes carbon-14 and hydrogen-3 (tritium) into the bulk gases, H 2 CO 2 and CH 4 may result in a radiological hazard to man. The purpose of this paper is to assess the mechanisms by which C-14 and tritium in solid low- and intermediate-level wastes are partitioned into gases reduced by corrosion and microbial processes. (author)

Carbon-14 radiolabelling and tissue distribution evaluation of a potential anti-TB compound.

Science.gov (United States)

Sonopo, Molahlehi S; Venter, Kobus; Winks, Susan; Marjanovic-Painter, Biljana; Morgans, Garreth L; Zeevaart, Jan R

2016-06-15

This paper describes a five-step synthesis of a carbon-14-labelled pyrazole compound (11). A total of 2.96 MBq of 11 was obtained with the specific activity of 2242.4 MBq/mmol. The radiochemical purity was >99%, and the overall radiochemical yield was 60% based on the [(14) C6 ] 4-bromoaniline starting material. Biodistribution results showed that the radiotracer (administrated orally) has a high accumulation in the small intestine, large intestine and liver of both non-infected and tuberculosis (TB)-infected mice. Therefore, this suggests that compound 11 undergoes hepatobiliary clearance. The compound under investigation has been found to be slowly released from the liver between 2 and 8 h. The study revealed that 11 has no affinity for TB cells. Copyright © 2016 John Wiley & Sons, Ltd.

Measurements of the interaction cross-sections for 14Be and 14,15B as projectiles with a new scheme at RIBLL

International Nuclear Information System (INIS)

Ozawa, A.; Cai, Y.Z.; Chen, Z.Q.; Chiba, M.; Fang, D.Q.; Guo, Z.G.; Izumikawa, T.; Li, J.X.; Mao, R.S.; Ohnishi, T.; Shen, W.Q.; Suda, T.; Sun, Z.Y.; Suzuki, T.; Tanihata, I.; Tian, W.D.; Wang, J.S.; Wang, M.; Wei, Y.B.; Xiao, G.Q.; Xiao, Z.G.; Yamaguchi, T.; Yamaguchi, Y.; Yoshida, A.; Zhan, W.L.; Zhang, H.Y.; Zheng, T.; Zhong, C.

2006-01-01

We have measured the interaction cross-sections (σ I ) for light neutron-rich nuclei ( 14 Be, 14,15 B) at ∼50A MeV at the Radioactive Ion Beam Line in Lanzhou (RIBLL) in IMP with a new scheme. In this scheme, a carbon reaction target was installed at the intermediate focusing point at RIBLL. This scheme allowed us to identify particles before and after the reaction target unambiguously. However, this scheme might suffer a large loss of transmission efficiency in the second half of RIBLL. We checked this effect by changing the emittance of the RI beams. The results showed that a correction of the transmission efficiency is needed to deduce σ I . We performed a Monte Carlo type simulation and tried to deduce σ I for the above nuclei. Finally, we obtained reasonable σ I although their error bars were fairly large. The results were compared with calculations by an energy-dependent semi-empirical formula

The synthesis of tritium, carbon-14 and stable isotope labelled selective estrogen receptor degraders.

Science.gov (United States)

Bragg, Ryan A; Bushby, Nick; Ericsson, Cecilia; Kingston, Lee P; Ji, Hailong; Elmore, Charles S

2016-09-01

As part of a Medicinal Chemistry program aimed at developing an orally bioavailable selective estrogen receptor degrader, a number of tritium, carbon-14, and stable isotope labelled (E)-3-[4-(2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl]prop-2-enoic acids were required. This paper discusses 5 synthetic approaches to this compound class. Copyright © 2016 John Wiley & Sons, Ltd.

14-3-3 zeta is a molecular target in guggulsterone induced apoptosis in Head and Neck cancer cells

International Nuclear Information System (INIS)

Macha, Muzafar A; Matta, Ajay; Chauhan, SS; Siu, KW Michael; Ralhan, Ranju

2010-01-01

The five-year survival rates for head and neck squamous cell carcinoma (HNSCC) patients are less than 50%, and the prognosis has not improved, despite advancements in standard multi-modality therapies. Hence major emphasis is being laid on identification of novel molecular targets and development of multi-targeted therapies. 14-3-3 zeta, a multifunctional phospho-serine/phospho-threonine binding protein, is emerging as an effector of pro-survival signaling by binding to several proteins involved in apoptosis (Bad, FKHRL1 and ASK1) and may serve as an appropriate target for head and neck cancer therapy. Herein, we determined effect of guggulsterone (GS), a farnesoid X receptor antagonist, on 14-3-3 zeta associated molecular pathways for abrogation of apoptosis in head and neck cancer cells. Head and neck cancer cells were treated with guggulsterone (GS). Effect of GS-treatment was evaluated using cell viability (MTT) assay and apoptosis was verified by annexin V, DNA fragmentation and M30 CytoDeath antibody assay. Mechanism of GS-induced apoptosis was determined by western blotting and co-IP assays using specific antibodies. Using in vitro models of head and neck cancer, we showed 14-3-3 zeta as a key player regulating apoptosis in GS treated SCC4 cells. Treatment with GS releases BAD from the inhibitory action of 14-3-3 zeta in proliferating HNSCC cells by activating protein phosphatase 2A (PP2A). These events initiate the intrinsic mitochondrial pathway of apoptosis, as revealed by increased levels of cytochrome c in cytoplasmic extracts of GS-treated SCC4 cells. In addition, GS treatment significantly reduced the expression of anti-apoptotic proteins, Bcl-2, xIAP, Mcl1, survivin, cyclin D1 and c-myc, thus committing cells to apoptosis. These events were followed by activation of caspase 9, caspase 8 and caspase 3 leading to cleavage of its downstream target, poly-ADP-ribose phosphate (PARP). GS targets 14-3-3 zeta associated cellular pathways for reducing

Coprecipitation of {sup 14}C and Sr with carbonate precipitates: The importance of reaction kinetics and recrystallization pathways

Energy Technology Data Exchange (ETDEWEB)

Hodkin, David J. [School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); Stewart, Douglas I. [School of Civil Engineering, University of Leeds (United Kingdom); Graham, James T. [National Nuclear Laboratory, Sellafield, Cumbria (United Kingdom); Burke, Ian T., E-mail: I.T.Burke@leeds.ac.uk [School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom)

2016-08-15

This study investigated the simultaneous removal of Sr{sup 2+} and {sup 14}CO{sub 3}{sup 2−} from pH > 12 Ca(OH){sub 2} solution by the precipitation of calcium carbonate. Initial Ca{sup 2+}:CO{sub 3}{sup 2−} ratios ranged from 10:1 to 10:100 (mM:mM). Maximum removal of {sup 14}C and Sr{sup 2+} both occurred in the system containing 10 mM Ca{sup 2+} and 1 mM CO{sub 3}{sup 2−} (99.7% and 98.6% removal respectively). A kinetic model is provided that describes {sup 14}C and Sr removal in terms of mineral dissolution and precipitation reactions. The removal of {sup 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 {sup 14}C back to solution. Sr{sup 2+} removal occurred as Ca{sup 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 {sup 90}Sr and {sup 14}C in radioactively contaminated waters (<$0.25 reagent cost per m{sup 3} treated). - Highlights: • 99.7% of {sup 14}C and 98.6% of Sr removed from aqueous solution by CaCO{sub 3} precipitation. • Remobilization of {sup 14}C observed during calcium carbonate recrystallization. • Sr displayed variable distribution coefficient (possibly affected by Ca:Sr ratio). • Reagent cost of $0.22/m{sup 3} of treated groundwater.

Experience of an inter-laboratory exercise for the determination of Carbon-14 in biological samples

International Nuclear Information System (INIS)

Baburajan, A.; Rajaram, S.; D'Souza, Renita Shiny; Nayak, Rasmi; Karunakara, N.; Ravi, P.M.; Tripathi, R.M.

2018-01-01

Carbon-14 is one of the naturally occurring cosmogenic nuclide with long half life of 5730 y and beta energy, E max : 156 keV produced continuously in the outer atmosphere. It is also produced by the anthropogenic activities like nuclear weapon test, nuclear power plant etc. contributing to the atmospheric inventory. The 14 CO 2 gets incorporated with the plant species during photosynthesis and ultimately reaches to man through food chain. It is important to accurately quantify the level of 14 C in different biological matrices for the computation of radiation dose due to ingestion. There are different methods available for the determination of 14 C in biological samples. The oxidation of the dried sample is one of the methods used for liberating the 14 CO 2 and which in turn re-absorbed using Carbo Sorb and subjected to Liquid scintillation analyses with Permaflour scintillator solution. The paper deals with the quality assurance programme initiated by ESL, Tarapur along with ESL, Kalpakkam and CARER, Mangalore University and share the experience of the inter-laboratory comparison exercise

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

International Nuclear Information System (INIS)

Prabakaran, K.; Fernandes, V.; McDonald, J.

1996-01-01

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

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)

Yunoki, Shunji; Saito, Masaaki; Nagakawa, Yoshiyasu

2012-01-01

The influence of atmospheric 14 CO 2 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 14 CO 2 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 14 CO 2 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 14 C 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 14 CO 2 decreased. We recommend that the influence of atmospheric 14 CO 2 should be corrected when fuel samples contain low amounts of 14 C. (author)

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.

Radioactive carbon-14 dating of ground waters in IPEN for evaluation of water resources in Rio Grande do Norte and Parana basin

International Nuclear Information System (INIS)

Chandra, U.; Pereira, M.C.

1986-01-01

14 C dating of deep ground waters from Potiguar basin and Parana basin was carried out to identify zones of recharge. In all 28 samples, five from Potiguar basin and 23 from Parana basin were analyzed for 14 C. The methods of sample collection and analysis are described. The analysis consists of transforming carbon of the sample to benzene, by synthesis process involving four steps i.e. production of carbon dioxide, production of lithium carbide, hydrolysis to acetylene and catalytic polymerization to bezene. The specific activity of the synthertized benzene is measured by liquid scintillation counting. The corrections for initial 14 C content have been made by using the model of Vogel. (Author) [pt

Synthesis of methyl ((chloro-2 ethyl)-3 nitroso-3 Ureido)-3 Didesoxy-2,3. alpha. -D-Arabino-hexopyrannoside labelled with carbon-14 or carbon-13 (CY 233 - SR 90008). Synthese du methyl ((chloro-2 ethyl)-3 nitroso-3 Ureido)-3 Didesoxy-2,3. alpha. -D-Arabino-hexopyrannoside marque au carbone-14 ou carbone-13 (CY 233 - SR 90008)

Energy Technology Data Exchange (ETDEWEB)

Sion, R.; Schumer, A.; Durme, E. van (Sanofi Recherche, Brussels (Belgium)); Gouyette, A. (Centre de Lutte Contre le Cancer Gustave-Roussy, 94 - Villejuif (France)); Geslin, M.; Fournier, J.P.; Roger, P. (Sanofi Recherche, Montrouge (France). Inst. Choay); Berger, Y. (Sanofi Recherche, Montpellier (France))

1990-06-01

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 {sup 14}C on (a) the carbonyl group of the urea in four stages starting with {sup 14}COCl{sub 2}, (b) the second carbon of the chloroethyl group in four stages starting with ({sup 14}C) ethanolamine, and (c) on the methyl group on the anomeric centre of the carbohydrate in three stages starting with {sup 14}CH{sub 3}OH. The final position was also labelled with {sup 13}C starting with {sup 13}CH{sub 3}OH. These differently labelled compounds are suitable for mechanistic studies of antitumour activity. (author).

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

Processing ix spent resin waste for C-14 isotope recovery

International Nuclear Information System (INIS)

Chang, F. H.; Woodall, K. B.; Sood, S. K.; Vogt, H. K.; Krochmainek, L. S.

1991-01-01

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 CANDU 1 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 m 3 of spent resins annually is being planned for demonstrating the technology. The measured C-14 activity levels on the spent resins ranged from 47

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...

Reduction of sources of error and simplification of the Carbon-14 urea breath test

International Nuclear Information System (INIS)

Bellon, M.S.

1997-01-01

Full text: Carbon-14 urea breath testing is established in the diagnosis of H. pylori infection. The aim of this study was to investigate possible further simplification and identification of error sources in the 14 C urea kit extensively used at the Royal Adelaide Hospital. Thirty six patients with validated H. pylon status were tested with breath samples taken at 10,15, and 20 min. Using the single sample value at 15 min, there was no change in the diagnostic category. Reduction or errors in analysis depends on attention to the following details: Stability of absorption solution, (now > 2 months), compatibility of scintillation cocktail/absorption solution. (with particular regard to photoluminescence and chemiluminescence), reduction in chemical quenching (moisture reduction), understanding counting hardware and relevance, and appropriate response to deviation in quality assurance. With this experience, we are confident of the performance and reliability of the RAPID-14 urea breath test kit now available commercially

The synthesis of the insecticides Aldrin and Dieldrin labelled with carbon-14 at high specific activity; Synthese des insecticides aldrine et dieldrine marques au carbone-14 de haute activite specifique; Sintez insektitsidnogo aldrina i dildrina, mechennykh uglerodom-14 pri vysokoj udel'noj aktivnosti; Sintesis de los insecticidas aldrin y dieldrin de elevada actividad especifica marcados con carbono-14

Energy Technology Data Exchange (ETDEWEB)

Thomas, Daniel J; Kilner, A Edward [Radiochemical Centre, UKAEA, Amersham, Bucks (United Kingdom)

1962-03-15

Aldrin is the trade name given by Shell Chemicals to 1, 2, 3, 4, 10, 10-hexachloro-1, 4, 4a, 5, 8, 8a-hexahydro-exo-1, 4-endo-5, 8-dimethanonapthalene. Acetylene-1, 2-C{sup 14} is converted successively to tetrachloroethane and trichloroethylene, and this is condensed with carbon tetrachloride by the Prins reaction in the presence of aluminium chloride to octachlorocyclopentene. Dechlorination gives hexachlorocyclopentadiene which undergoes a Diels-Alder addition to bicyclo(2, 2, 1) hepta-2,5-diene to give aldrin-C{sup 14} in 12% yield from barium carbonate. Oxidation of Aldrin gives the 6,7 epoxide, Dieldrin, in 87% yield. The paper includes an account of the separation of octachlorocyclopentene from the crude product of the Prins reaction by gas-liquid chromatography and of the separation of Aldrin and Dieldrin on a small preparative scale by reversed-phase paper chromatography. (author) [French] Aldrine est la denomination commerciale par laquelle la Shell Chemicals designe l'hexachloro-1, 2, 3, 4, 10, 10-hexahydro-1, 4, 4a, 5, 8, 8a-exo-endo-1,4- dimethano-5, 8-naphtalene. L'acetylene-1,2-C{sup 14} est successivement transforme en terachloroethane et en trichloroethylene, lequel se condense avec le tetrachlorure de carbone, par la reaction de Prins, en presence de chlorure d'aluminium, pour donner de l'octachlorocyclopentene. La dechloruration fournit de l'hexachlorocyclopentadiene, lequel, par une synthese de Diels-Alder, se transforme en bicyclohepta(2, 2, 1)-diene-2, 5 pour donner de l'aldrine-C{sup 14}, avec un rendement de 12% par rapport au carbonate de baryum. L'oxydation de l'aldrine donne l'epoxyde-6 7-(dieldrine), avec un rendement de 87%. Les auteurs decrivent, en outre, la separation de l'octachlorocyclopentene par chromatographie gaz-liquide, a partir du produit brut de la reaction de Prins, ainsi que la separation de l'aldrine et de la dieldrine, en petite quantite, par chromatographie sur papier a phase renversee. (author) [Spanish] Aldrin es el

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

International Nuclear Information System (INIS)

Liffers, Sven-T; Schwarte-Waldhoff, Irmgard; Meyer, Helmut E; Stühler, Kai; Hahn, Stephan A; Maghnouj, Abdelouahid; Munding, Johanna B; Jackstadt, René; Herbrand, Ulrike; Schulenborg, Thomas; Marcus, Katrin; Klein-Scory, Susanne; Schmiegel, Wolff

2011-01-01

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. 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. 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. 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 suppressive circuitry

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)

Vende, L.

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 (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 ( 14 CO 2 , HT...) or in solution ( 14 CO 3 2- , 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)

Automatic counting and recording unit used for dating by the carbon 14 method; Ensemble de comptage et d'impression automatique utilise pour la datation par la methode du carbone 14

Energy Technology Data Exchange (ETDEWEB)

Albertinoli, P; Galliot, J; Thommeret, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Centre Scientifique de Monaco, Monte Carlo

1969-07-01

A description is given of the unit used by the 'Centre Scientifique de Monaco' for low-level beta counting and fitted for radioactive dating by the Carbon 14 method. Built entirely by the laboratory in 1964, on the basis of electronic techniques then recent, it has worked without failure since that time. The proportional counter, its high-voltage negative supply, and the counting chains with visual and printing records are detailed by means of 38 figures which reproduce the counter and the electronic circuits. These are contained in two standard 5 U.I structures. The low-voltage power supply of the whole unit is carried out by plus 12 volts and minus 12 volts storage batteries, buffered on a charger connected on the 110 V alternative line. The proportional counter described is filled with CO{sub 2} under one atmosphere pressure and permits the dating of carbonaceous samples with a maximum of 30.000 + 1.000 years (background 3.96 c.p.m. ) within a moderate time (72 hours). (authors) [French] L'ensemble de comptage pour radioactivite beta a bas niveau, destine a la datation par la methode du carbone 14, utilise au Centre Scientifique de Monaco, est decrit. Entierement construit au laboratoire en 1964, sur la base de techniques electroniques alors recentes, il fonctionne depuis cette date sans defaillance. Le compteur proportionnel, son alimentation haute tension negative et les chaines de comptage transistorisees a affichage et impression sont detailles par 38 schemas reproduisant le compteur et les divers circuits electroniques. Ceux-ci sont contenus dans deux chassis standard 5 UI. L'alimentation basse tension de l'ensemble est obtenue par batteries plus 12 et moins 12 volts montees en tampon sur chargeur alimente par le reseau. Le compteur proportionnel decrit, rempli de CO2 sous une atmosphere, permet de dater les echantillons carbones avec un maximum de 30.000 + 1.000 ans (bruit de fond: 3,96 c.p.m. ) en un temps raisonnable (72 heures). (auteur)

THEODORE, a two-step heating system for the EC/OC determination of radiocarbon (14C) in the environment

International Nuclear Information System (INIS)

Szidat, S.; Jenk, T.M.; Gaeggeler, H.W.; Synal, H.-A.; Hajdas, I.; Bonani, G.; Saurer, M.

2004-01-01

Measurements of 14 C in the organic carbon (OC) and elemental carbon (EC) fractions, respectively, of fine aerosol particles bear the potential to apportion anthropogenic and biogenic emission sources. For this purpose, the system THEODORE (two-step heating system for the EC/OC determination of radiocarbon in the environment) was developed. In this device, OC and EC are transformed into carbon dioxide in a stream of oxygen at 340 and 650 deg. C, respectively, and reduced to filamentous carbon. This is the target material for subsequent accelerator mass spectrometry (AMS) 14 C measurements, which were performed on sub-milligram carbon samples at the PSI/ETH compact 500 kV AMS system. Quality assurance measurements of SRM 1649a, Urban Dust, yielded a fraction of modern f M in total carbon (TC) of 0.522 ± 0.018 (n=5, 95% confidence level) in agreement with reported values. The results for OC and EC are 0.70 ± 0.05 (n=3) and 0.066 ± 0.020 (n=4), respectively

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

International Nuclear Information System (INIS)

Seidl, P.A.

1985-02-01

Cross sections for the /sup 13,14/C, 26 Mg, 56 Fe(π + ,π - )/sup 13,14/O, 26 Si, 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 π/ less than or equal to 292 MeV and 0 less than or equal to theta less than or equal to 50. The double isobaric analog states (DIAS) are of primary interest. In addition, cross sections for transitions to 14 O(0 + , 5.92 MeV), 14 O(2 + , 7.77 MeV), 56 Ni(gs), 13 O(gs), and 13 O(4.21 MeV) are presented. The 13 O(4.21 MeV) state is postulated to have J/sup π/ = 1/2 - . The data are compared to previously measured double-charge-exchange cross sections on other nuclei, and the systematics of double charge exchange on T greater than or equal to 1 target nuclei leading to the DIAS are studied. Near the Δ 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 π/ > 200 MeV the anomalous features of the 164 MeV data are not apparent. This is evidence for significant higher order contributions to the double-charge-exchange amplitude near the reasonable energy. Two theoretical approaches that include two nucleon processes are applied to the DIAS data. 64 references

Large-scale Patterns of 14C Age of Bulk Organic Carbon and Various Molecular Components in Grassland Soils

Science.gov (United States)

Jia, J.; Liu, Z.; Cao, Z.; Chen, L.; He, J. S.; Haghipour, N.; Wacker, L.; Eglinton, T. I.; Feng, X.

2017-12-01

Unraveling the fate of organic carbon (OC) in soils is essential to understanding the impact of global changes on the global carbon cycle. Previous studies have shown that while various soil OC components have different decomposability, chemically labile OC can have old 14C ages. However, few studies have compared the 14C age of various soil OC components on a large scale, which may provide important information on the link between the age or turnover of soil OC components to their sources, molecular structures as well as environmental variables. In this project, a suite of soil profiles were sampled along a large-scale transect of temperate and alpine grasslands across the Tibetan and Mongolian Plateaus in China with contrasting climatic, vegetation and soil properties. Bulk OC and source-specific compounds (including fatty acids (FAs), diacids (DAs) and lignin phenols) were radiocarbon-dated to investigate the age and turnover dynamics of different OC pools and the mechanisms controlling their stability. Our results show that lignin phenols displayed a large 14C variability. Short-chain (C16, 18) FAs sourced from vascular plants as well as microorganisms were younger than plant-derived long-chain FAs and DAs, indicating that short-chain FAs were easier to be decomposed or newly synthesized. In the temperate grasslands, long-chain DAs were younger than FAs, while the opposite trend was observed in the alpine grasslands. Preliminary correlation analysis suggests that the age of short-chain FAs were mainly influenced by clay contents and climate, while reactive minerals, clay or silt particles were important factors in the stabilization of long-chain FAs, DAs and lignin phenols. Overall, our study provided a unique 14 C dataset of soil OC components in grasslands, which will provide important constraints on soil carbon turnover in future investigations.

{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.

SMART marine goals, targets and management - Is SDG 14 operational or aspirational, is 'Life Below Water' sinking or swimming?

Science.gov (United States)

Cormier, Roland; Elliott, Michael

2017-10-15

The United Nations Sustainable Development Goals (SDG), adopted in September 2015, are accompanied by targets which have to be met individually and collectively by the signatory states. SDG14 Life Below Water aims to lay the foundation for the integrated and sustainable management of the oceans. However, any environmental management has to be based around targets which are SMART - specific, measurable, achievable, realistic and time bounded - otherwise it is not possible to determine whether management actions are successful and achieve the desired aims. The discussion here shows that many of the targets adopted for SDG14, and especially a detailed analysis of Target 1, are aspirational rather than fully quantified. In order to move towards making the targets operational, we advocate merging the language of environmental management with that used by industry for linking risks to the environment, management performance and ensuing controls. By adopting an approach which uses Key Performance Indicators ('KPIs'), Key Risk Indicators ('KRIs') and Key Control Indicators ('KCIs'), we advocate that a degree of rigour leading to defendable actions can be brought to marine management. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

Hesboel, R.; Puigdomenech, I.; Evans, S.

1990-01-01

The source term, isolation capacity, and long-term radiological exposure of 14 C from the Swedish underground repository for low and intermediate level waste (SFR) is assessed. The prospective amount of 14 C in the repository is assumed to be 5 TBq. Spent ion exchange resins will be the dominant source of 14 C. The pore water in the concrete repository is expected to maintain a pH of >10.5 for a period of at least 10 6 y. The cement matrix of the repository will retain most of the 14 CO 3 2- initially present. Bacterial production of CO 2 and CH 4 from degradation of ion-exchange resins and bitumen may contribute to 14 C release to the biosphere. However, CH 4 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 2.4x10 4 years. A total leakage of 8.4 GBq of 14 C from the repository will cause a total collective dose commitment of 1.1 manSv or 130 manSv TBq -1 . (authors)

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

International Nuclear Information System (INIS)

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

2010-01-01

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 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 14 C/C ratio, independent of chemical separation procedures. The isotope ratio measurement was specific (owing to the 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 14 C corresponds to 30 fg equivalents. AMS

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

Synthesis of [3-14C]- and [phenyl-U-14C] olaquindox

International Nuclear Information System (INIS)

Maul, W.; Scherling, D.; Seng, F.

1981-01-01

Olaquindox is a new feed additive. [ 14 C]Olaquindox, labelled in different positions, was needed for tracer-studies of pharmacokinetics, biotransformation and residues in several species of animals. 2-[N-(2-hydroxethyl)-carbamoyl]-3-methyl-[3- 14 C]quinoxaline-1,4-dioxide([3- 14 C]Olaquindox) was synthesized from barium[ 14 C]carbonate (22 mmoles; 1.15 Ci) via [1- 14 C]acetic acid, sodium[1- 14 C]acetate, [1- 14 C]acetylchloride, ethyl[3- 14 C]acetoacetate and 2-carbethoxy-3-methyl-[3- 14 C]quinoxaline-1,4-dioxide with an overall yield of 10%, based on barium[ 14 C]carbonate. The radiochemical purity was better than 98% (tlc). The specific activities of three preparations were 10.5, 8.4 and 5.45 μCi/mg respectively. [phenyl-U- 14 C]Olaquindox was synthesized starting from [U- 14 C]aniline (19.8 mmoles; 284.4 mCi). Intermediate products were N-acetyl[U- 14 C]aniline, 2-nitro-N-acetyl[U- 14 C]aniline, 2-nitro[U- 14 C]aniline and [U- 14 C]benzofurazanoxide. The total yield was 50% as calculated for [U- 14 C]aniline. At calibration samples of two preparations showed specific activities of 49.5 and 11.1 μCi/mg respectively. The radiochemical purity was checked by tlc and exceeded 98%. (author)

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)...

Interaction of 14 MeV neutrons with hydrogenated target proton emission calculation

International Nuclear Information System (INIS)

Martin, G.; Perez, N.; Desdin.

1996-01-01

Using neutron emission data of a 14 MeV neutron generator, a paraffin target, and based on the n + H 1 → n '+ p reaction, have been obtained the characteristics of the proton emission in a proton-neutron mixed field. It was used Monte Carlo simulation and it was obtained the proton output as function of the converter width and the energy spectrum of protons corresponding to different converter thickness. Among 0.07 and 0.2 cm there is a maximum zone for the proton emission. The energy spectrum agrees with obtained on previous papers. Figures showing these results are provided

The synthesis of carbon-14 labeled pravastatin

International Nuclear Information System (INIS)

Wallace, M.A.; Dean, D.C.; Ellsworth, R.L.; Melillo, D.G.; Marks, T.; White, R.F.

1993-01-01

An asymmetric route to [ 14 C]β-hydroxycompactin 1 bearing the (S)-2-methyl-[1- 14 C]butanoate side chain has been developed. Methylation of [N-[1- 14 C]butyryl]-4-(S)-phenylmethyl-2-oxazolidinone 4 afforded a 95:5 mixture of diastereomeric [N-(S,R)-2-methyl-[1- 14 C]butyryl]-4-(S)-phenylmethyl-2-oxazolidi nones 5,6 which were separated by preparative HPLC. Oxidative cleavage of 5 afforded optically pure (S)-2-methyl-[1- 14 C]butanoic acid. Acylation of alcohol 9 with optically pure (S)-2-methyl-[1- 14 C] butyryl chloride afforded ester 10. Removal of the silyl ether produced diastereomerically pure compactin 11. Hydroxylation was carried out by biotransformation with Mucor hiemelus to afford diastereomerically pure [[1- 14 C]butanoate]β-hydroxycompactin, [ 14 C]Pravastatin 1. (Author)

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)

Sion, R.; Schumer, A.; Durme, E. van; Gouyette, A.; Geslin, M.; Fournier, J.P.; Roger, P.

1990-01-01

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 14 C on a) the carbonyl group of the urea in four stages starting with 14 COCl 2 , b) the second carbon of the chloroethyl group in four stages starting with [ 14 C] ethanolamine, and c) on the methyl group on the anomeric centre of the carbohydrate in three stages starting with 14 CH 3 OH. The final position was also labelled with 13 C starting with 13 CH 3 OH. These differently labelled compounds are suitable for mechanistic studies of antitumour activity. (author)

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

International Nuclear Information System (INIS)

Fischer, E.; Mueller, H.

1980-01-01

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 14 C- and of the 3 H-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 3 H-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.) [de

Use of carbon-14 in soil organic matter studies

International Nuclear Information System (INIS)

Vimal, O.P.; Kamath, M.B.

1974-01-01

Despite a great deal of research work on various aspects of soil organic matter, there are many gaps in the knowledge of the process of humus formation. These limitations arise mainly from the complex and heterogenous nature of soil humus substances, analytical problems in separating the fresh and decomposable materials from the old stabilized true humus substances and the lack of a clear understanding of the chemical structure of the humic acid molecule. During recent years, the use of carbon-14 has helped to trace within soil, transformation of a number of metabolites upto the point where they turn into humus. These studies have changed the concepts of the formation and stability of soil humus substances, their colloidal chemical properties and the uptake of organomolecules by plant roots. The present paper presents a synoptic view of the use of radiocarbon in studying the kinetics of humification, nature of precursors in humic acid formation, turnover of soil organic matter and the direct effects of humus substances on plant growth. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Ohno, N. [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)], E-mail: ohno@ees.nagoya-u.ac.jp; Yoshimi, M. [Department of Energy Engineering and Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tokitani, M. [National Institute for Fusion Science, Oroshi 322-6, Toki 509-5292 (Japan); Takamura, S. [Department of Electronics, Aichi Institute of Technology, Yakusa-cho, Toyota 470-0392 (Japan); Tokunaga, K.; Yoshida, N. [Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)

2009-06-15

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

Impacts of low-carbon power policy on carbon mitigation in Guangdong Province, China

International Nuclear Information System (INIS)

Cheng, Beibei; Dai, Hancheng; Wang, Peng; Xie, Yang; Chen, Li; Zhao, Daiqing; Masui, Toshihiko

2016-01-01

This paper analyzes the impacts of the low-carbon policy in the power sector of Guangdong Province in China on its energy and carbon emission targets by 2020, as well as their costs and co-benefits, using a regional CGE model with seven scenarios: business as usual (BaU), renewable energy (RE), renewable energy and natural gas (RE–NG), CAP only (CAP), CAP and RE–NG (CAP–RE–NG), carbon emission trading (ETS), and ETS with RE–NG (ETS–RE–NG). Analysis results reveal that provincial energy and carbon intensity targets can be achieved in the assumed carbon mitigation scenarios with carbon cap, ETS, and clean energy development policies. While the carbon constraint exerts negative impacts on the economy, GDP loss could be lowered by the ETS and RE policies. The RE scenario is more economically efficient than the ETS scenario, and coupling the RE and ETS scenarios appears to be the most economically efficient scenario to achieve the desired carbon and energy intensity targets. One of the benefits of the low-carbon policy is its improvement of the energy security of Guangdong in terms of reduced reliance on external coal and oil; in particular, Guangdong coal consumption could peak in 2017–2019. - Highlights: • This study analyzes the low carbon policy in the power sector in Guangdong of China. • The role of power sector in achieving carbon and energy intensity target is shown. • Renewable energy and natural gas are very important for Guangdong Province. • Additional efforts in other sectors are needed to achieve the intensity targets. • The mitigation cost and economic impacts are assessed under various policy settings.

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)

Dubois, Ludwig; Peeters, Sarah G.J.A.; Kuijk, Simon J.A. van; Yaromina, Ala; Lieuwes, Natasja G.; Saraya, Ruchi; Biemans, Rianne; Rami, Marouan; Parvathaneni, Nanda Kumar; Vullo, Daniela; Vooijs, Marc; Supuran, Claudiu T.; Winum, Jean-Yves

2013-01-01

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

Carbon isotopes of dissolved inorganic carbon reflect utilization of different carbon sources by microbial communities in two limestone aquifer assemblages

Directory of Open Access Journals (Sweden)

M. E. Nowak

2017-08-01

Full Text Available Isotopes of dissolved inorganic carbon (DIC are used to indicate both transit times and biogeochemical evolution of groundwaters. These signals can be complicated in carbonate aquifers, as both abiotic (i.e., carbonate equilibria and biotic factors influence the δ13C and 14C of DIC. We applied a novel graphical method for tracking changes in the δ13C and 14C of DIC in two distinct aquifer complexes identified in the Hainich Critical Zone Exploratory (CZE, a platform to study how water transport links surface and shallow groundwaters in limestone and marlstone rocks in central Germany. For more quantitative estimates of contributions of different biotic and abiotic carbon sources to the DIC pool, we used the NETPATH geochemical modeling program, which accounts for changes in dissolved ions in addition to C isotopes. Although water residence times in the Hainich CZE aquifers based on hydrogeology are relatively short (years or less, DIC isotopes in the shallow, mostly anoxic, aquifer assemblage (HTU were depleted in 14C compared to a deeper, oxic, aquifer complex (HTL. Carbon isotopes and chemical changes in the deeper HTL wells could be explained by interaction of recharge waters equilibrated with post-bomb 14C sources with carbonates. However, oxygen depletion and δ13C and 14C values of DIC below those expected from the processes of carbonate equilibrium alone indicate considerably different biogeochemical evolution of waters in the upper aquifer assemblage (HTU wells. Changes in 14C and 13C in the upper aquifer complexes result from a number of biotic and abiotic processes, including oxidation of 14C-depleted OM derived from recycled microbial carbon and sedimentary organic matter as well as water–rock interactions. The microbial pathways inferred from DIC isotope shifts and changes in water chemistry in the HTU wells were supported by comparison with in situ microbial community structure based on 16S rRNA analyses. Our findings

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)

2012-01-01

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 14 C 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 14 C 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 14 C 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 14 C, 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

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

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-06-15

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 {sup 14}C 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 {sup 14}C 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 {sup 14}C 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 {sup 14}C, 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

Radiocarbon (14C) Concentration of Local Pollution in Street Trees Located at Intersections

OpenAIRE

Ogawa, Daisuke

2018-01-01

At large intersections, vehicles consume and generate a large amount of fossil fuel. Carbon derived from fossil fuels that do not contain radioactive carbon (14C), i.e., dead carbon, is released in large amounts in the roadside air environment. By means of photosynthesis, street trees along the roadside assimilate both dead carbon, not containing radioactive carbon (14C), and contemporary carbon, which includes radioactive carbon (14C). Therefore, the concentration of radioactive carbon (14C)...

Micro-syntheses for the use of carbon 13 or carbon 14. Micro-preparations of methyl alcohol, methyl iodide, and sodium acetate labeled in the methyl group; Microsyntheses pour l'emploi de carbone 13 ou de carbone 14. Micropreparations d'alcool methylique, d'iodure de methyle et d'acetate de sodium marque sur le groupement methyle

Energy Technology Data Exchange (ETDEWEB)

Baret, C; Pichat, L

1951-11-01

Apparatus and technique are described in detail for (1) reduction of CO{sub 2} to CH{sub 3}OH with LiAlH{sub 4}, (2) conversion of the methanol to CH{sub 3}I by HI, (3) formation of the Mg Grignard reagent, and (4) addition of inactive CO{sub 2} to form CH{sub 3}COOH. All these operations have been carried out on 0.005 moles. Methyl-labeled Na acetate has been prepared in 67% yield based on the Ba{sup 14}CO{sub 3} used as starting material. (author) [French] Description detaillee d'une technique deja connue pour la reduction du gaz carbonique en alcool methylique par LiAlH{sub 4}. Conversion du methanol en iodure de methyle. Ce dernier transforme en reactif de Grigard, et carbonate, fournit de l'acide acetique. Toutes ces operations on ete effectuees sur 5 x 10{sup -3} moles. La methode a ete appliquee a la synthese d'acetate de sodium marque par le groupement methyle par {sup 14}C avec un rendement global de 67% base sur le carbonate de baryum radioactif mis en oeuvre. (auteurs)

Using Targeted Active-Learning Exercises and Diagnostic Question Clusters to Improve Students' Understanding of Carbon Cycling in Ecosystems

Science.gov (United States)

Maskiewicz, April Cordero; Griscom, Heather Peckham; Welch, Nicole Turrill

2012-01-01

In this study, we used targeted active-learning activities to help students improve their ways of reasoning about carbon flow in ecosystems. The results of a validated ecology conceptual inventory (diagnostic question clusters [DQCs]) provided us with information about students' understanding of and reasoning about transformation of inorganic and organic carbon-containing compounds in biological systems. These results helped us identify specific active-learning exercises that would be responsive to students' existing knowledge. The effects of the active-learning interventions were then examined through analysis of students' pre- and postinstruction responses on the DQCs. The biology and non–biology majors participating in this study attended a range of institutions and the instructors varied in their use of active learning; one lecture-only comparison class was included. Changes in pre- to postinstruction scores on the DQCs showed that an instructor's teaching method had a highly significant effect on student reasoning following course instruction, especially for questions pertaining to cellular-level, carbon-transforming processes. We conclude that using targeted in-class activities had a beneficial effect on student learning regardless of major or class size, and argue that using diagnostic questions to identify effective learning activities is a valuable strategy for promoting learning, as gains from lecture-only classes were minimal. PMID:22383618

Using targeted active-learning exercises and diagnostic question clusters to improve students' understanding of carbon cycling in ecosystems.

Science.gov (United States)

Maskiewicz, April Cordero; Griscom, Heather Peckham; Welch, Nicole Turrill

2012-01-01

In this study, we used targeted active-learning activities to help students improve their ways of reasoning about carbon flow in ecosystems. The results of a validated ecology conceptual inventory (diagnostic question clusters [DQCs]) provided us with information about students' understanding of and reasoning about transformation of inorganic and organic carbon-containing compounds in biological systems. These results helped us identify specific active-learning exercises that would be responsive to students' existing knowledge. The effects of the active-learning interventions were then examined through analysis of students' pre- and postinstruction responses on the DQCs. The biology and non-biology majors participating in this study attended a range of institutions and the instructors varied in their use of active learning; one lecture-only comparison class was included. Changes in pre- to postinstruction scores on the DQCs showed that an instructor's teaching method had a highly significant effect on student reasoning following course instruction, especially for questions pertaining to cellular-level, carbon-transforming processes. We conclude that using targeted in-class activities had a beneficial effect on student learning regardless of major or class size, and argue that using diagnostic questions to identify effective learning activities is a valuable strategy for promoting learning, as gains from lecture-only classes were minimal.

Target laboratory

International Nuclear Information System (INIS)

Ephraim, D.C.; Pednekar, A.R.

1993-01-01

A target laboratory to make stripper foils for the accelerator and various targets for use in the experiments is set up in the pelletron accelerator facility. The facilities available in the laboratory are: (1) D.C. glow discharge setup, (2) carbon arc set up, and (3) vacuum evaporation set up (resistance heating), electron beam source, rolling mill - all for target preparation. They are described. Centrifugal deposition technique is used for target preparation. (author). 3 figs

Carbon-14 in reactor plant water

International Nuclear Information System (INIS)

Knowles, G.K.

1979-01-01

The method for the analysis of 14 C in reactor plant water and various waste streams previously used at the Idaho National Engineering Laboratory has been shown to be ineffective for samples which contain organic compounds. The previous method consisted of acidification and refluxing of the sample, precipitation of the liberated CO 2 , and subsequent analysis by the liquid scintillation method. The method was simple but it did not convert all compounds containing 14 C in the sample to CO 2 . The new method, while it is based on the previous method, has been improved by employing a strong oxidant, potassium persulfate and silver nitrate, for more complete oxidation of the organics to CO 2 . The new method yields 14 C values that have typically been one to two orders of magnitude higher than the values obtained using the former method. This indicates that most of the 14 C present in the current reactor water samples being analyzed is associated with trace amounts of organics

14C measurements in aquifers with methane

International Nuclear Information System (INIS)

Barker, J.F.; Fritz, P.; Brown, R.M.

1978-01-01

A survey of various groundwater systems indicates that methane is a common trace constituent and occasionally a major carbon species in groundwaters. Thermocatalytic methane had delta 13 CCH 4 > -45% 0 and microbially-produced or biogenic methane had delta 13 CCH 4 0 . Groundwaters containing significant biogenic methane had abnormally heavy delta 13 C values for the inorganic carbon. Thermocatalytic methane had no apparent effect on the inorganic carbon. Because methanogenesis seriously affects the carbon isotope geochemistry of groundwaters, the correction of raw 14 C ages of affected groundwaters must consider these effects. Conceptual models are developed which adjust the 14 C activity of the groundwater for the effects of methanogenesis and for the dilution of carbon present during infiltration by simple dissolution of rock carbonate. These preliminary models are applied to groundwaters from the Alliston sand aquifer where methanogenesis has affected most samples. In this system, methanogenic bacteria using organic matter present in the aquifer matrix as substrate, have added inorganic carbon to the groundwater which has initiated further carbonate rock dissolution. These processes have diluted the inorganic carbon 14 C activity. (orig.) [de

Physical consequences of the mitochondrial targeting of single-walled carbon nanotubes probed computationally

Science.gov (United States)

Chistyakov, V. A.; Zolotukhin, P. V.; Prazdnova, E. V.; Alperovich, I.; Soldatov, A. V.

2015-06-01

Experiments by F. Zhou and coworkers (2010) [16] showed that mitochondria are the main target of the cellular accumulation of single-walled carbon nanotubes (SWCNTs). Our in silico experiments, based on geometrical optimization of the system consisting of SWCNT+proton within Density Functional Theory, revealed that protons can bind to the outer side of SWCNT so generating a positive charge. Calculation results allow one to propose the following mechanism of SWCNTs mitochondrial targeting. SWCNTs enter the space between inner and outer membranes of mitochondria, where the excess of protons has been formed by diffusion. In this compartment SWCNTs are loaded with protons and acquire positive charges distributed over their surface. Protonation of hydrophobic SWCNTs can also be carried out within the mitochondrial membrane through interaction with the protonated ubiquinone. Such "charge loaded" particles can be transferred as "Sculachev ions" through the inner membrane of the mitochondria due to the potential difference generated by the inner membrane. Physiological consequences of the described mechanism are discussed.

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

Energy Technology Data Exchange (ETDEWEB)

Kim, Jangheon; Kim, Soohyun [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong, Yuseong, Daejeon 305-806 (Korea, Republic of); Kim, Gi Gyu; Jung, Wonsuk, E-mail: wonsuk81@wku.ac.kr [Department of Mechanical and Automotive Engineering, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of)

2016-05-16

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.

Abiotic and bioaugmented granular activated carbon for the treatment of 1,4-dioxane-contaminated water.

Science.gov (United States)

Myers, Michelle A; Johnson, Nicholas W; Marin, Erick Zerecero; Pornwongthong, Peerapong; Liu, Yun; Gedalanga, Phillip B; Mahendra, Shaily

2018-06-04

1,4-Dioxane is a probable human carcinogen and an emerging contaminant that has been detected in surface water and groundwater resources. Many conventional water treatment technologies are not effective for the removal of 1,4-dioxane due to its high water solubility and chemical stability. Biological degradation is a potentially low-cost, energy-efficient approach to treat 1,4-dioxane-contaminated waters. Two bacterial strains, Pseudonocardia dioxanivorans CB1190 (CB1190) and Mycobacterium austroafricanum JOB5 (JOB5), have been previously demonstrated to break down 1,4-dioxane through metabolic and co-metabolic pathways, respectively. However, both CB1190 and JOB5 have been primarily studied in laboratory planktonic cultures, while most environmental microbes grow in biofilms on surfaces. Another treatment technology, adsorption, has not historically been considered an effective means of removing 1,4-dioxane due to the contaminant's low K oc and K ow values. We report that the granular activated carbon (GAC), Norit 1240, is an adsorbent with high affinity for 1,4-dioxane as well as physical dimensions conducive to attached bacterial growth. In abiotic batch reactor studies, 1,4-dioxane adsorption was reversible to a large extent. By bioaugmenting GAC with 1,4-dioxane-degrading microbes, the adsorption reversibility was minimized while achieving greater 1,4-dioxane removal when compared with abiotic GAC (95-98% reduction of initial 1,4-dioxane as compared to an 85-89% reduction of initial 1,4-dioxane, respectively). Bacterial attachment and viability was visualized using fluorescence microscopy and confirmed by amplification of taxonomic genes by quantitative polymerase chain reaction (qPCR) and an ATP assay. Filtered samples of industrial wastewater and contaminated groundwater were also tested in the bioaugmented GAC reactors. Both CB1190 and JOB5 demonstrated 1,4-dioxane removal greater than that of the abiotic adsorbent controls. This study suggests that

(CH4)-C-14 Measurements in Greenland Ice: Investigating Last Glacial Termination CH4 Sources

DEFF Research Database (Denmark)

Petrenko, V. V.; Smith, A. M.; Brook, E. J.

2009-01-01

by direct cosmogenic C-14 production in ice. C-14 of CO was measured to better understand this process and correct the sample (CH4)-C-14. Corrected results suggest that wetland sources were likely responsible for the majority of the Younger Dryas-Preboreal CH4 rise.......The cause of a large increase of atmospheric methane concentration during the Younger Dryas-Preboreal abrupt climatic transition (similar to 11,600 years ago) has been the subject of much debate. The carbon-14 (C-14) content of methane ((CH4)-C-14) should distinguish between wetland and clathrate...... contributions to this increase. We present measurements of (CH4)-C-14 in glacial ice, targeting this transition, performed by using ice samples obtained from an ablation site in west Greenland. Measured (CH4)-C-14 values were higher than predicted under any scenario. Sample (CH4)-C-14 appears to be elevated...

A First Look at Target Mode Retrievals of CO2 from the Orbiting Carbon Observatory-2 (OCO-2)

Science.gov (United States)

Natraj, V.; Taylor, T.; Smyth, M.; Fisher, B.; O'Dell, C.; Pollock, H. R.; Crisp, D.

2014-12-01

The Orbiting Carbon Observatory-2 (OCO-2) is NASA's first dedicated Earth remote sensing satellite to study atmospheric carbon dioxide from space, and was launched successfully on July 2, 2014. OCO-2 is designed to quantify the sources and sinks of CO2by making highly precise measurements of its column abundance. OCO-2 has three science observation modes - nadir, glint and target. In the nadir mode, the satellite points the instrument to the local nadir, so that data can be collected along the ground track just below the spacecraft. In the glint mode, the spacecraft points the instrument toward the bright "glint" spot, where solar radiation is specularly reflected from the surface. In the target mode, the Observatory will lock its view onto a specific surface location, and will scan back and forth over that target while flying overhead. A target track pass can last for up to 9 minutes. Over that time period, the Observatory can acquire as many as 12,960 samples at local zenith angles that vary between 0° and 85°. Here, we analyze target track measurements over several of the OCO-2 validation sites where ground-based solar-looking Fourier Transform Spectrometers are located. The target scan serves two purposes. The first is to collect a large number of measurements over surface calibration and validation targets to assess the precision and accuracy of the retrieved column averaged CO2 dry air mole fraction (XCO2). The second is to look for spatial variations in column averaged CO2 dry air mole fraction (XCO2) in the vicinity of the target that could compromise the value of the measurements for calibration or validation. To meet both requirements, we compare XCO2 retrievals as a function of both observation angle and scan location, and investigate whether those variations are coming from instrument calibration, algorithmic deficiencies, aerosols/clouds or real CO2variations. Further, simulated retrievals indicate that target observations can show large sensitivity

Preparation of carbon-14-labelled gallic acid

International Nuclear Information System (INIS)

Kozak, I.; Prochazka, M.

1977-01-01

Gallic acid labelled with 14 C was prepared for the needs of biological studies. A lithium derivative of trimethoxybenzene was treated with 14 CO 2 and then demethylated to yeld [carboxyl- 14 C]gallic acid. The preparation scheme and the individual steps of the synthesis are described in detail

A survey of methods to immobilize tritium and carbon-14 arising from a nuclear fuel reprocessing plant

International Nuclear Information System (INIS)

Taylor, P.

1991-02-01

This report reviews the literature on methods to separate and immobilize tritium ( 3 H) and carbon-14 ( 14 C) released from U0 2 fuel in a nuclear fuel reprocessing plant. It was prepared as part of a broader review of fuel reprocessing waste management methods that might find future application in Canada. The calculated inventories of both 3 H and 14 C in used fuel are low; special measures to limit releases of these radionuclides from reprocessing plants are not currently in place, and may not be necessary in future. If required, however, several possible approaches to the concentration and immobilization of both radionuclides are available for development. Technology to control these radionuclides in reactor process streams is in general more highly developed than for reprocessing plant effluent, and some control methods may be adaptable to reprocessing applications

Reaction cross sections for 8He and 14B on proton target for the separation of proton and neutron density distributions

International Nuclear Information System (INIS)

Tanaka, Masaomi; Fukuda, Mitsunori; Nishimura, Daiki

2015-01-01

We utilized the proton-neutron asymmetry of nucleon–nucleon total cross sections in the intermediate energy region (σ pn ≠σ pp(nn) ) to obtain the information of proton and neutron distributions respectively. We have measured reaction cross sections (σ R ) for 14 B and 8 He on proton targets as isospin asymmetric targets in addition to symmetric ones. Proton and neutron density distributions were derived respectively through the χ 2 -fitting procedure with the modified Glauber calculation. The result suggests a necessity for 14 B of a long tail, and also a necessity for 8 He of a neutron tail. Root-mean-square proton, neutron and matter radii for 14 B and 8 He are also derived. Each radius is consistent with some of the other experimental values and also with some of the several theoretical values. (author)

miR-150-5p inhibits hepatoma cell migration and invasion by targeting MMP14.

Directory of Open Access Journals (Sweden)

Tao Li

Full Text Available Hepatocellular carcinoma (HCC is one of the leading causes of cancer-related mortality worldwide. Despite progress in diagnostics and treatment of HCC, its prognosis remains poor because the molecular mechanisms underlying hepatocarcinogenesis are not well understood. In the study, we focused on identifying the role of miRNAs in HCC progression. miRNA microarray was used to analyze the differentially expressed miRNAs, and the results were validated by qPCR. We found that the miR-150-5p expression is down-regulated in HCC tissues compared with pair non-tumor tissues. miR-150-5p expression is also decreased in metastatic cancer tissues compared with pair primary tissues, indicating that miR-150-5p may be involved in HCC metastasis. Functionally, miR-150-5p inhibition significantly promotes hepatoma cell migration and invasion, whereas miR-150-5p overexpression suppresses cancer cell migration and invasion in vitro. The matrix metalloproteinase 14 (MMP14 is identified as a new target gene of miR-150-5p. miR-150-5p markedly inhibits MMP14 expression in hepatoma cells, and miR-150-5p expression is negative correlation with MMP14 expression in vivo. More important, re-expression of MMP14 in hepatoma cells partially reverses the effect of miR-150-5p in inhibiting cell invasion.

A perspective on tritium versus carbon-14: ensuring optimal label selection in pharmaceutical research and development.

Science.gov (United States)

Krauser, Joel A

2013-01-01

Tritium ((3) H) and carbon-14 ((14) C) labels applied in pharmaceutical research and development each offer their own distinctive advantages and disadvantages coupled with benefits and risks. The advantages of (3) H have a higher specific activity, shorter half-life that allows more manageable waste remediation, lower material costs, and often more direct synthetic routes. The advantages of (14) C offer certain analytical benefits and less potential for label loss. Although (3) H labels offer several advantages, they might be overlooked as a viable option because of the concerns about its drawbacks. A main drawback often challenged is metabolic liability. These drawbacks, in some cases, might be overstated leading to underutilization of a perfectly viable option. As a consequence, label selection may automatically default to (14) C, which is a more conservative approach. To challenge this '(14) C-by-default' approach, pharmaceutical agents with strategically selected (3) H-labeling positions based on non-labeled metabolism data have been successfully implemented and evaluated for (3) H loss. From in-house results, the long term success of projects clearly would benefit from a thorough, objective, and balanced assessment regarding label selection ((3) H or (14) C). This assessment should be based on available project information and scientific knowledge. Important considerations are project applicability (preclinical and clinical phases), synthetic feasibility, costs, and timelines. Copyright © 2013 John Wiley & Sons, Ltd.

Quantitative carbon-14 autoradiography at the cellular level: principles and application for cell kinetic studies

International Nuclear Information System (INIS)

Doermer, P.

1981-01-01

Amounts of radio-labelled substances as low as 10 -18 moles incorporated into individual cells can be measured by utilizing techniques of quantitative autoradiography. The principles and application of quantitative carbon-14 autoradiography are reviewed. Silver grain densities can be counted by automated microphotometry allowing on-line data processing by an interfaced computer. Rate measurements of 14 C-thymidine incorporation into individual cells yield values of the DNA synthesis rate and the DNA synthesis time of a cell compartment can be derived. This is an essential time parameter for the evaluation of kinetic events in proliferating cell populations. This method is applicable to human cells without radiation hazard to man and provides an optimal source of detailed information on the kinetics of normal and diseased human haematopoiesis. Examples of application consist of thalassaemia, malaria infection, iron deficiency anaemia and acute myelogenous leukaemia. (author)

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.)

The preparation of nucleotides uniformly labelled with carbon-14 by biosinthetic methods. Isolation of adenilic, uridilic, cytidilic and guanlic acids, from the alkaline hydrolisate of escherichia coli RNA

International Nuclear Information System (INIS)

Garcia Pineda, D.; Pacheco Lopez, J.

1978-01-01

A method is described for the preparation and analysis of adenilic, uridilic, cytidylic and guanilic acids, labelled with carbon 14. Escherichia coli cells have been labelled by growing them in media containing glucose-carbon 14 as their only source of carbon. RNA is isolated from the cells, and after hydrolisis 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. The distribution of radioactivity incorporated in the cell among different groups of molecular species is analyse. (author)

Carbon-14 dating of a mummy from 'Caverna da Babilonia', Rio Novo Country, south of Minas Gerais (MG, Brazil)

International Nuclear Information System (INIS)

Beltrao, M. da C.M.C.; Danon, J.; Poupeau, G.

1985-01-01

The vegetable fibers of a cloth wrapping a mummy of a woman, found in 'Caverna da Babilonia' (MG, Brazil), were dated with carbon-14. There is strong evidence that it is a pre-colombian mummym since the age of the sample is 600 + - 80 years (1σ). (C.L.B.) [pt

ESDに向けての14C測定の利用

OpenAIRE

中村, 俊夫; 太田, 友子; 西田, 真砂美; Nakamura, Toshio; Ohta, Tomoko; Nishida, Masami

2015-01-01

We have measured 14C concentration of plastic bag samples to confirm that the plastic bags were produced from sustainable carbon, carbon contained in living plants, instead of fossil carbon. Three plastic bags used for normal shopping of food carrier had descriptions on the bag that they were produced from sustainable carbon in some amount. To check the amount of carbon from recent plant remains, we have measured 14C concentrations of the plastic bag samples. The 14C contents were consistent ...

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 ...

The use of 14C ethanolamine as a precursor

International Nuclear Information System (INIS)

Madelmont, J.C.; Parry, D.; Godeneche, D.; Duprat, J.

1985-01-01

Two new 2 chloroethyl nitrosoureas were labelled on two positions by 14 C starting from Na 14 CN and using 14 C 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)

A Monte Carlo investigation of low-Z target image quality generated in a linear accelerator using Varian's VirtuaLinac

International Nuclear Information System (INIS)

Parsons, David; Robar, James L.; Sawkey, Daren

2014-01-01

Purpose: The focus of this work was the demonstration and validation of VirtuaLinac with clinical photon beams and to investigate the implementation of low-Z targets in a TrueBeam linear accelerator (Linac) using Monte Carlo modeling. Methods: VirtuaLinac, a cloud based web application utilizing Geant4 Monte Carlo code, was used to model the Linac treatment head components. Particles were propagated through the lower portion of the treatment head using BEAMnrc. Dose distributions and spectral distributions were calculated using DOSXYZnrc and BEAMdp, respectively. For validation, 6 MV flattened and flattening filter free (FFF) photon beams were generated and compared to measurement for square fields, 10 and 40 cm wide and at d max for diagonal profiles. Two low-Z targets were investigated: a 2.35 MeV carbon target and the proposed 2.50 MeV commercial imaging target for the TrueBeam platform. A 2.35 MeV carbon target was also simulated in a 2100EX Clinac using BEAMnrc. Contrast simulations were made by scoring the dose in the phosphor layer of an IDU20 aSi detector after propagating through a 4 or 20 cm thick phantom composed of water and ICRP bone. Results: Measured and modeled depth dose curves for 6 MV flattened and FFF beams agree within 1% for 98.3% of points at depths greater than 0.85 cm. Ninety three percent or greater of points analyzed for the diagonal profiles had a gamma value less than one for the criteria of 1.5 mm and 1.5%. The two low-Z target photon spectra produced in TrueBeam are harder than that from the carbon target in the Clinac. Percent dose at depth 10 cm is greater by 3.6% and 8.9%; the fraction of photons in the diagnostic energy range (25–150 keV) is lower by 10% and 28%; and contrasts are lower by factors of 1.1 and 1.4 (4 cm thick phantom) and 1.03 and 1.4 (20 cm thick phantom), for the TrueBeam 2.35 MV/carbon and commercial imaging beams, respectively. Conclusions: VirtuaLinac is a promising new tool for Monte Carlo modeling of novel

Chemoenzymatic synthesis of carbon-14 labelled antioxidants

International Nuclear Information System (INIS)

Deigner, H.P.; Freyberg, C.; Heck, R.

1993-01-01

The syntheses of [ 14 C] labelled antioxidants are described. We developed an efficient synthetic methodology to prepare a series of labelled amides with antioxidant activity, starting from [ 14 C] KCN and alkyl or aryl halides. By a combination of nucleophilic displacement of halides by [ 14 C] cyanide, mediated by ultrasound and subsequent mild and selective enzymatic hydrolysis of the resulting nitriles, labelled carboxylic acids were obtained. Labelled amines were prepared by reduction of the respective nitriles. Availability of [ 14 C] KCN, efficient introduction of the label by ultrasound mediated reaction and selective and mild hydrolysis by commercially available nitrilase (Rhodococcus sp.), makes possible a wide range of applications of this methodology in the synthesis of functionalized labelled compounds. (Author)

Incremental diagnostic value of targeted biopsy using mpMRI-TRUS fusion versus 14-fragments prostatic biopsy. A prospective controlled study

International Nuclear Information System (INIS)

Mariotti, Guilherme C.; Falsarella, Priscila M.; Garcia, Rodrigo G.; Queiroz, Marcos R.G.; Lemos, Gustavo C.; Baroni, Ronaldo H.

2018-01-01

To compare the incremental diagnostic value of targeted biopsy using real-time multiparametric magnetic resonance imaging and transrectal ultrasound (mpMRI-TRUS) fusion to conventional 14-cores biopsy. Uni-institutional, institutional review board (IRB) approved prospective blinded study comparing TRUS-guided random and targeted biopsy using mpMRI-TRUS fusion, in 100 consecutive men. We included men with clinical-laboratorial suspicious for prostate cancer and Likert score ≥ 3 mp-MRI. Patients previously diagnosed with prostate cancer were excluded. All patients were submitted to 14-cores TRUS-guided biopsy (mpMRI data operator-blinded), followed by targeted biopsy using mpMRI-TRUS fusion. There was an overall increase in cancer detection rate, from 56% with random technique to 62% combining targeted biopsy using mpMRI-TRUS fusion; incremental diagnosis was even more relevant for clinically significant lesions (Gleason ≥ 7), diagnosing 10% more clinically significant lesions with fusion biopsy technique. Diagnosis upgrade occurred in 5 patients that would have negative results in random biopsies and had clinically significant tumours with the combined technique, and in 5 patients who had the diagnosis of significant tumours after fusion biopsy and clinically insignificant tumours in random biopsies(p=0.0010). Targeted biopsy using mpMRI-TRUS fusion has incremental diagnostic value in comparison to conventional random biopsy, better detecting clinically significant prostate cancers. (orig.)

Incremental diagnostic value of targeted biopsy using mpMRI-TRUS fusion versus 14-fragments prostatic biopsy. A prospective controlled study

Energy Technology Data Exchange (ETDEWEB)

Mariotti, Guilherme C.; Falsarella, Priscila M.; Garcia, Rodrigo G.; Queiroz, Marcos R.G. [Hospital Israelita Albert Einstein, Department of Interventional Radiology, Sao Paulo (Brazil); Lemos, Gustavo C. [Hospital Israelita Albert Einstein, Department of Urology, Sao Paulo (Brazil); Baroni, Ronaldo H. [Hospital Israelita Albert Einstein, Department of Radiology, Sao Paulo (Brazil)

2018-01-15

To compare the incremental diagnostic value of targeted biopsy using real-time multiparametric magnetic resonance imaging and transrectal ultrasound (mpMRI-TRUS) fusion to conventional 14-cores biopsy. Uni-institutional, institutional review board (IRB) approved prospective blinded study comparing TRUS-guided random and targeted biopsy using mpMRI-TRUS fusion, in 100 consecutive men. We included men with clinical-laboratorial suspicious for prostate cancer and Likert score ≥ 3 mp-MRI. Patients previously diagnosed with prostate cancer were excluded. All patients were submitted to 14-cores TRUS-guided biopsy (mpMRI data operator-blinded), followed by targeted biopsy using mpMRI-TRUS fusion. There was an overall increase in cancer detection rate, from 56% with random technique to 62% combining targeted biopsy using mpMRI-TRUS fusion; incremental diagnosis was even more relevant for clinically significant lesions (Gleason ≥ 7), diagnosing 10% more clinically significant lesions with fusion biopsy technique. Diagnosis upgrade occurred in 5 patients that would have negative results in random biopsies and had clinically significant tumours with the combined technique, and in 5 patients who had the diagnosis of significant tumours after fusion biopsy and clinically insignificant tumours in random biopsies(p=0.0010). Targeted biopsy using mpMRI-TRUS fusion has incremental diagnostic value in comparison to conventional random biopsy, better detecting clinically significant prostate cancers. (orig.)

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.

Functionalized single-walled carbon nanotube-based fuel cell benchmarked against US DOE 2017 technical targets.

Science.gov (United States)

Jha, Neetu; Ramesh, Palanisamy; Bekyarova, Elena; Tian, Xiaojuan; Wang, Feihu; Itkis, Mikhail E; Haddon, Robert C

2013-01-01

Chemically modified single-walled carbon nanotubes (SWNTs) with varying degrees of functionalization were utilized for the fabrication of SWNT thin film catalyst support layers (CSLs) in polymer electrolyte membrane fuel cells (PEMFCs), which were suitable for benchmarking against the US DOE 2017 targets. Use of the optimum level of SWNT -COOH functionality allowed the construction of a prototype SWNT-based PEMFC with total Pt loading of 0.06 mg(Pt)/cm²--well below the value of 0.125 mg(Pt)/cm² set as the US DOE 2017 technical target for total Pt group metals (PGM) loading. This prototype PEMFC also approaches the technical target for the total Pt content per kW of power (<0.125 g(PGM)/kW) at cell potential 0.65 V: a value of 0.15 g(Pt)/kW was achieved at 80°C/22 psig testing conditions, which was further reduced to 0.12 g(Pt)/kW at 35 psig back pressure.

Use of the small gas proportional counters for the carbon-14 measurement of very small samples

International Nuclear Information System (INIS)

Sayre, E.V.; Harbottle, G.; Stoenner, R.W.; Otlet, R.L.; Evans, G.V.

1981-01-01

Two recent developments are: the first is the mass-spectrometric separation of 14 C and 12 C ions, followed by counting of the 14 C, while the second is the extension of conventional proportional counter operation, using CO 2 as counting gas, to very small counters and samples. Although the second method is slow (months of counting time are required for 10 mg of carbon) it does not require operator intervention and many samples may be counted simultaneously. Also, it costs only a fraction of the capital expense of an accelerator installation. The development, construction and operation of suitable small counters are described, and results of three actual dating studies involving milligram scale carbon samples will be given. None of these could have been carried out if conventional, gram-sized samples had been needed. New installations, based on the use of these counters, are under construction or in the planning stages. These are located at Brookhaven Laboratory, the National Bureau of Standards (USA) and Harwell (UK). The Harwell installation, which is in advanced stages of construction, will be described in outline. The main significance of the small-counter method is, that although it will not suffice to measure the smallest (much less than 10 mg) or oldest samples, it will permit existing radiocarbon laboratories to extend their capability considerably, in the direction of smaller samples, at modest expense

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

Invariant mass spectroscopy of {sup 19,17}C and {sup 14}B using proton inelastic and charge-exchange reactions

Energy Technology Data Exchange (ETDEWEB)

Satou, Y., E-mail: satou@phya.snu.ac.k [Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of); Nakamura, T. [Department of Physics, Tokyo Institute of Technology, Tokyo (Japan); Fukuda, N. [Institute of Physical and Chemical Research (RIKEN), Saitama (Japan); Sugimoto, T.; Kondo, Y.; Matsui, N.; Hashimoto, Y.; Nakabayashi, T.; Okumura, Y.; Shinohara, M. [Department of Physics, Tokyo Institute of Technology, Tokyo (Japan); Motobayashi, T.; Yanagisawa, Y.; Aoi, N.; Takeuchi, S.; Gomi, T.; Togano, Y. [Institute of Physical and Chemical Research (RIKEN), Saitama (Japan); Kawai, S. [Department of Physics, Rikkyo University, Tokyo (Japan); Sakurai, H. [Institute of Physical and Chemical Research (RIKEN), Saitama (Japan); Ong, H.J.; Onishi, T.K. [Department of Physics, University of Tokyo, Tokyo (Japan)

2010-03-01

The neutron-rich carbon isotopes {sup 19,17}C and the boron isotope {sup 14}B have been investigated, respectively, by the proton inelastic and charge-exchange reactions on a liquid hydrogen target at around 70 MeV/nucleon. The invariant mass method in inverse kinematics was employed to map the energy spectrum above the neutron decay threshold of the residual nuclei. New states on carbon isotopes are reported. An experimental capability of extracting beta-decay strengths via forward angle (p,n) cross sections on unstable nuclei is shown.

Adherence problem for carbon films of up to 0.5 mg/cm2 on vacuum-deposited thick ferromagnetic Gd targets

International Nuclear Information System (INIS)

Maier-Komor, P.; Kruecken, R.; Speidel, K.-H.; Kenn, O.

2004-01-01

For high precision measurements of magnetic moments and reduced transition probabilities by the combined technique of projectile Coulomb excitation in inverse kinematics and transient magnetic fields sandwich targets of carbon and gadolinium were required. First preparations revealed a lack of adhesion between the Gd film and the vacuum-deposited C layer. Either the adhesion was generally poor or good results could not be reproduced. Now on a 4 mg/cm 2 Gd target 0.5 mg/cm 2 of nat C should be deposited. The Gd was deposited on 1-1.6 mg/cm 2 Ta backings and Cu films of 3.5-7 mg/cm 2 were deposited on the reverse side of the Ta backings. The adhesive properties of evaporated carbon on ferromagnetic gadolinium were investigated. For this either substrate cooling or the deposition of a 5 μg/cm 2 Ti film as adhesion agent were applied

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)

Gas-phase noncovalent functionalization of carbon nanotubes with a Ni(II) tetraaza[14]annulene complex

Science.gov (United States)

Basiuk, Vladimir A.; Henao-Holguín, Laura Verónica; Álvarez-Zauco, Edgar; Bassiouk, María; Basiuk, Elena V.

2013-04-01

The noncovalent functionalization of carbon nanotubes (CNTs) with aromatic polyazamacrocyclic compounds, based on π-π-interactions, keeps the intrinsic electronic structure of CNTs totally intact and allows for combining unique properties of the two interacting components. In addition to porphyrins and phthalocyanines, there are other, simpler compounds exhibiting similar properties, potentially useful for photovoltaic, catalytic and electrochemical applications: for example, tetraaza[14]annulenes. Many of them are highly thermally stable, which makes it possible to employ physical vapor deposition for the preparation of macrocycle-nanotube hybrids. One of such compounds is Ni(II) complex of 5,7,12,14-tetramethyldibenzo-1,4,8,11-tetraazacyclotetradeca-3,5,7,10,12,14-hexaene (also called Ni(II)-tetramethyldibenzotetraaza[14]annulene, or NiTMTAA for simplicity). In the present work, we attempted the noncovalent functionalization of both single-walled and multi-walled CNTs with NiTMTAA in the gas phase at two selected temperatures of 220 and 270 °C, which does not require the use of organic solvents and therefore can be considered as ecologically friendly. The nanohybrids obtained were characterized by means of scanning and transmission electron microscopy, energy dispersive X-ray, Fourier-transform infrared and Raman spectroscopy, as well as thermogravimetric analysis. An additional insight into the structure of adsorption complexes of NiTMTAA on CNTs was provided from density functional theory and molecular mechanics calculations.

Gas-phase noncovalent functionalization of carbon nanotubes with a Ni(II) tetraaza[14]annulene complex

Energy Technology Data Exchange (ETDEWEB)

Basiuk, Vladimir A., E-mail: basiuk@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510, México D.F. (Mexico); Henao-Holguín, Laura Verónica [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510, México D.F. (Mexico); Álvarez-Zauco, Edgar [Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior C.U., 04510, México D.F. (Mexico); Bassiouk, María [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510, México D.F. (Mexico); Basiuk, Elena V. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510, México D.F. (Mexico)

2013-04-01

The noncovalent functionalization of carbon nanotubes (CNTs) with aromatic polyazamacrocyclic compounds, based on π–π-interactions, keeps the intrinsic electronic structure of CNTs totally intact and allows for combining unique properties of the two interacting components. In addition to porphyrins and phthalocyanines, there are other, simpler compounds exhibiting similar properties, potentially useful for photovoltaic, catalytic and electrochemical applications: for example, tetraaza[14]annulenes. Many of them are highly thermally stable, which makes it possible to employ physical vapor deposition for the preparation of macrocycle–nanotube hybrids. One of such compounds is Ni(II) complex of 5,7,12,14-tetramethyldibenzo-1,4,8,11-tetraazacyclotetradeca-3,5,7,10,12, 14-hexaene (also called Ni(II)-tetramethyldibenzotetraaza[14]annulene, or NiTMTAA for simplicity). In the present work, we attempted the noncovalent functionalization of both single-walled and multi-walled CNTs with NiTMTAA in the gas phase at two selected temperatures of 220 and 270 °C, which does not require the use of organic solvents and therefore can be considered as ecologically friendly. The nanohybrids obtained were characterized by means of scanning and transmission electron microscopy, energy dispersive X-ray, Fourier-transform infrared and Raman spectroscopy, as well as thermogravimetric analysis. An additional insight into the structure of adsorption complexes of NiTMTAA on CNTs was provided from density functional theory and molecular mechanics calculations.

Gas-phase noncovalent functionalization of carbon nanotubes with a Ni(II) tetraaza[14]annulene complex

International Nuclear Information System (INIS)

Basiuk, Vladimir A.; Henao-Holguín, Laura Verónica; Álvarez-Zauco, Edgar; Bassiouk, María; Basiuk, Elena V.

2013-01-01

The noncovalent functionalization of carbon nanotubes (CNTs) with aromatic polyazamacrocyclic compounds, based on π–π-interactions, keeps the intrinsic electronic structure of CNTs totally intact and allows for combining unique properties of the two interacting components. In addition to porphyrins and phthalocyanines, there are other, simpler compounds exhibiting similar properties, potentially useful for photovoltaic, catalytic and electrochemical applications: for example, tetraaza[14]annulenes. Many of them are highly thermally stable, which makes it possible to employ physical vapor deposition for the preparation of macrocycle–nanotube hybrids. One of such compounds is Ni(II) complex of 5,7,12,14-tetramethyldibenzo-1,4,8,11-tetraazacyclotetradeca-3,5,7,10,12, 14-hexaene (also called Ni(II)-tetramethyldibenzotetraaza[14]annulene, or NiTMTAA for simplicity). In the present work, we attempted the noncovalent functionalization of both single-walled and multi-walled CNTs with NiTMTAA in the gas phase at two selected temperatures of 220 and 270 °C, which does not require the use of organic solvents and therefore can be considered as ecologically friendly. The nanohybrids obtained were characterized by means of scanning and transmission electron microscopy, energy dispersive X-ray, Fourier-transform infrared and Raman spectroscopy, as well as thermogravimetric analysis. An additional insight into the structure of adsorption complexes of NiTMTAA on CNTs was provided from density functional theory and molecular mechanics calculations.

Transformation of the herbicide [14C]glufosinate in soils

International Nuclear Information System (INIS)

Smith, A.E.

1989-01-01

The degradation of 2 μg/g [ 14 C]glufosinate (DL-homoalan-4-ylmethylphosphinic acid) was studied in clay, clay loam, and sandy loam soils at 85% field capacity and at 20 degree C. Over a 4-week period the soils were extracted and analyzed for transformation products by radiochemical and gas chromatographic techniques. In all soils there was release of [ 14 C]carbon dioxide and formation of [ 14 C]-3-(hydroxymethylphosphinyl)propionic acid (MPPA) as major degradation products. Within 21 days, about 55% of the applied 14 C herbicide had been transformed to MPPA in the sandy loam and 19% to [ 14 C]carbon dioxide. After 28 days, approximately 45% of the 14 C herbicide had been transformed to MPPA in the clay and clay loam and 10% released as [ 14 C]carbon dioxide. At all samplings, other 14 C transformation products appeared to be insignificant

Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons

International Nuclear Information System (INIS)

Raisbeck, G.M.; Lestringuez, J.; Yiou, F.

1975-01-01

Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons were measured by mass spectrometry. The results are compared with lower energy measurements and discussed in terms of the variation of the cosmic ray L/M ratio in this energy region [fr

Carbon-14 Specific Activity Model Validation for Biota in Wetland Environments

International Nuclear Information System (INIS)

Yankovich, T.L.; Sharp, K.J.; Benz, M.L.; Carr, J.; Killey, R.W.D.

2008-01-01

In many cases, contaminants, such as radionuclides, can show highly localized spatial distributions in natural systems. Therefore, a key question for environmental assessment and monitoring becomes, how can these localized distributions of contaminants in the environment lead to organism exposure, and ultimately, the potential for effects to receptor biota? To address this question, an important first step is to conduct field surveys at sites of interest to map out the spatial distribution and extent of contaminants in areas that are being occupied and utilized by resident receptor biota. Work can then be conducted to establish predictive relationships between contaminant concentrations in biota tissues and those in environmental media with which biota interact, to gain an understanding of how representative ambient contaminant concentrations are of biota exposure. The objectives of this study were: - To conduct a field survey in a wetland ecosystem to characterize the spatial distribution of carbon- 14 ( 14 C), a radionuclide with dynamics in natural systems that can be described using a specific activity model; and - To determine whether 14 C concentrations in environmental media reflect those measured in tissues of resident flora and fauna. A detailed field campaign was carried out in summer 2001 to characterize the spatial distribution and areal coverage of 14 C in Duke Swamp, a wetland ecosystem on Atomic Energy of Canada Limited (AECL)'s Chalk River Laboratories (CRL) site that receives 14 C through releases from an up-gradient Waste Management Area (WMA), primarily through groundwater influx. Sampling of surface vegetation (dominantly comprised of Sphagnum moss) was conducted at a total of 69 locations, with complementary sampling of air, soil, fungi, aerial insects, ground-dwelling insects, amphibians, small mammals and snakes being carried out at a subset of five locations with varying 14 C concentrations. Concentrations of 14 C in resident Duke Swamp

Preparation of tantalum targets of known thicknesses

International Nuclear Information System (INIS)

Alexander, J.R.; Wirth, H.L.

1985-01-01

A series of carbon-backed tantalum targets were produced in a heavy ion sputtering system with a Penning ion source. The target thicknesses were then measured using the alpha-ray energy loss method. The resulting tabulated measurements were reproducible and make possible the production of carbon-backed tantalum targets with pre-determined thicknesses ranging from 20 μg/cm 2 to 1 mg/cm 2 . (orig.)

C14 Assays and Autoradiographic Studies on the Rooster Comb

Science.gov (United States)

Balazs, Endre A.; Szirmai, John A.; Bergendahl, Gudrun

1959-01-01

The distribution of C14 was studied in various parts of the rooster comb following treatment with testosterone. The value of gas-phase assay of C14 in tissue has been demonstrated and the results compared with those of autoradiographic studies on the same tissue. The results of these experiments showed that androgen treatment significantly increases the rate of incorporation of C14 in various parts of the comb. The specific activity of carbon in the comb, cornea, and liver differed, depending on which precursor, viz. glucose-6-C14, glucose-1-C14, and glucuronolactone-U-C14, was administered. The highest values were obtained after the administration of glucose-6-C14; glucuronolactone-U-C14 gave the lowest specific activity. The specific activity of carbon in different parts of the comb showed considerable variation. Carbon assay of serial sections of the comb cut at various planes showed that the specific activity of carbon was highest in the mucoid layer. Both C14 assays and autoradiograms indicate that C14 is also present in other parts of the comb. As seen in autoradiography, the concentration of C14 was highest in the epithelium, in the blood vessel walls, and in the avascular collagenous tissue. These results, and indications from previous studies, suggest that the high specific activity of carbon in the mucoid layer is due mainly to the presence of C14-labelled hyaluronic acid. Autoradiograms and PAS staining suggest that a significant amount of C14 is also incorporated into the glycoproteins associated with the collagen fibers. PMID:13654453

Syntheses of [6-14C] and [5-carboxy, 6-14C2]nitrendipine

International Nuclear Information System (INIS)

Maul, N.; Scherling, D.

1989-01-01

[6- 14 C]Nitrendipine synthesis started from barium[ 14 ]carbonate, which was converted to [1- 14 C]acetyl chloride. The acid chloride was condensed with Meldrum's acid (2,2-dimethyl-1,3-dioxane-4,6-dione). The resulting intermediate was treated with boiling methanol to give methyl [3- 14 C]acetoacetate. The reaction with gaseous ammonia in toluene yielded the corresponding methyl 3-amino[3- 14 C]crotonate which was condensed with ethyl 2-(3-nitro-benzylidene) acetoacetate to obtain [6- 14 C]nitrendipine. (author)

Target fragmentation in deep inelastic scattering of 14.5 GeV electrons from nuclei

International Nuclear Information System (INIS)

Degtyarenko, P.; Gavrilov, V.; Shuvalov, S.

1993-01-01

Results will be presented for inclusive pion, kaon, proton and deuteron electroproduction from light nuclei (mainly 12 C and 16 O) of the residual gas in the beam pipe of the TPC/2γ detector at SLAC. Counter-circulating beams of 14.5 GeV electrons and positrons were used. Comparison will be made with the fragmentation of 2 H, 40 Ar, and Xe target nuclei in several regions of Q 2 and ν. The dependence of the hadron production on the hadron's kinetic energy, emission angle, and x f will be presented. The results will be compared with models of nuclear fragmentation

Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons

International Nuclear Information System (INIS)

Raisbeck, G.M.; Lestringuez, J.; Yiou, F.

1975-01-01

Cross sections for the production of Li and Be isotopes in carbon targets irradiated by 300 GeV protons have been measured by mass spectrometry. The results are compared with lower energy measurements and discussed in terms of the variation of the cosmic ray L/M ratio in the energy region [fr

Evaluation of carbon-14 (C14) levels of terrestrial and marine food products of the environment of the site of Cogema La Hague

International Nuclear Information System (INIS)

2006-04-01

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.)

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

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)

Sandberg, Johannes

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

Soil carbon dynamics inferred from carbon isotope compositions of soil organic matter and soil respiration

International Nuclear Information System (INIS)

Koarashi, Jun; Asano, Tomohiro; Iida, Takao; Moriizumi, Jun

2004-01-01

To better understand 14 C cycling in terrestrial ecosystems, 14 C abundances were evaluated for fractionated soil organic matter (SOM) and soil respiration in an urban forest. In 2001 soil profile, Δ 14 C values of litter and bulk SOM increased rapidly from litter surface (62.7 per mille) to uppermost mineral soil layer (244.9 per mille), and then decreased sharply to 6 cm depth of mineral soil (125.0 per mille). Carbon enriched in 14 C by atmospheric nuclear weapons testing had penetrated to at least 16 cm depth of mineral soil. The average Δ 14 C in atmospheric CO 2 was 58.8 per mille in August 2001, suggesting recent carbon input to the topmost litter layer. Although a similar depth distribution was observed for Δ 14 C values of residual SOM after acid hydrolysis, the Δ 14 C values were slightly lower than those in bulk SOM. This indicates input of 'bomb' C into this organic fraction and higher 14 C abundance in acid-soluble SOM. The most of CO 2 may be derived from the microbial decomposition of the acid-soluble, or labile, SOM. Therefore, the labile SOM may become most influential pool for soil carbon cycling. In contrast, carbon in base-insoluble SOM remained considerably low in 14 C abundance at all depths, suggesting no or little incorporation of 'bomb' C to this fraction. Values of Δ 14 C in soil respiration ranged from 91.9 to 146.4 per mille in August 2001, showing a significant contribution from decomposition of SOM fixed over past 2-40 years. These results indicate that the use of bulk SOM as a representative of soil carbon pool would lead to severe misunderstand of the soil C dynamics on decadal and shorter time scales. (author)

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)

Taylor, E.M.; Huckins, H.E.

1995-01-01

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

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

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, Bernhard; Braakhekke, M.C.|info:eu-repo/dai/nl/343063689; Guggenberger, Georg; Schrumpf, Marion; Reichstein, Markus

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

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

International Nuclear Information System (INIS)

Kong, Fung-Ming.

1989-03-01

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

Carbon in high-purity germanium

International Nuclear Information System (INIS)

Haller, E.E.; Hansen, W.L.; Luke, P.; McMurray, R.; Jarrett, B.

1981-10-01

Using 14 C-spiked pyrolytic graphite-coated quartz crucibles for the growth of nine ultra-pure germanium single crystals, we have determined the carbon content and distribution in these crystals. Using autoradiography, we observe a rapidly decreasing carbon cluster concentration in successively grown crystals. Nuclear radiation detectors made from the crystals measure the betas from the internally decaying 14 C nuclei with close to 100% efficiency. An average value for the total carbon concentration [ 14 C + 12 C] is approx. 2 x 10 14 cm -3 , a value substantially larger than expected from earlier metallurgical studies. Contrary to the most recent measurement, we find the shape of the beta spectrum to agree very well with the statistical shape predicted for allowed transitions

A double harmonic buncher for the 14-UD pelletron

International Nuclear Information System (INIS)

Jain, H.C.; Sharma, R.P.; Bhalerao, P.J.; Datar, V.M.

1986-01-01

A preliminary test report of a double harmonic buncher fabricated for obtaining pulsed heavy ion beams from the 14-UD pelletron being installed at the Tata Insitute of Fundamental Research (TIFR), Bombay is presented. The tests were carried out at the 300 keV heavy-ion-accelerator in operation at TIFR. The bunched beam was studied by detecting the electrons produced as the beam was scattered from a carbon target. Figures showing the schematic diagram of the buncher and the time spectra of beam bunching obtained with 200 keV 40 Ar and 90 keV 16 O ions using only the fundamental frequency are given. (M.G.B.)

On the isolation of elemental carbon (EC) for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

Science.gov (United States)

Currie, L. A.; Kessler, J. D.

2005-10-01

The primary objective of the research reported here has been the development of a hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are vital 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 (char) from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK) and thermal optical transmission (TOT) methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS). As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1) both methods exhibited biomass-C "leakage"; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC) isolated contained about 3% of the original biomass-C.; (2) the initial isothermal oxidation stage of

On the isolation of elemental carbon (EC for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK EC isolation procedure

Directory of Open Access Journals (Sweden)

L. A. Currie

2005-01-01

Full Text Available The primary objective of the research reported here has been the development of a hybrid reference material (RM to serve as a test of accuracy for elemental carbon (EC isotopic (14C speciation measurements. Such measurements are vital 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 (char from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK and thermal optical transmission (TOT methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS. As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1 both methods exhibited biomass-C 'leakage'; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC isolated contained about 3% of the original biomass-C.; (2 the initial isothermal oxidation stage

RGD-conjugated silica-coated gold nanorods on the surface of carbon nanotubes for targeted photoacoustic imaging of gastric cancer

Science.gov (United States)

Wang, Can; Bao, Chenchen; Liang, Shujing; Fu, Hualin; Wang, Kan; Deng, Min; Liao, Qiande; Cui, Daxiang

2014-05-01

Herein, we reported for the first time that RGD-conjugated silica-coated gold nanorods on the surface of multiwalled carbon nanotubes were successfully used for targeted photoacoustic imaging of in vivo gastric cancer cells. A simple strategy was used to attach covalently silica-coated gold nanorods (sGNRs) onto the surface of multiwalled carbon nanotubes (MWNTs) to fabricate a hybrid nanostructure. The cross-linked reaction occurred through the combination of carboxyl groups on the MWNTs and the amino group on the surface of sGNRs modified with a silane coupling agent. RGD peptides were conjugated with the sGNR/MWNT nanostructure; resultant RGD-conjugated sGNR/MWNT probes were investigated for their influences on viability of MGC803 and GES-1 cells. The nude mice models loaded with gastric cancer cells were prepared, the RGD-conjugated sGNR/MWNT probes were injected into gastric cancer-bearing nude mice models via the tail vein, and the nude mice were observed by an optoacoustic imaging system. Results showed that RGD-conjugated sGNR/MWNT probes showed good water solubility and low cellular toxicity, could target in vivo gastric cancer cells, and obtained strong photoacoustic imaging in the nude model. RGD-conjugated sGNR/MWNT probes will own great potential in applications such as targeted photoacoustic imaging and photothermal therapy in the near future.

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.

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

International Nuclear Information System (INIS)

Porter, A E; Bendall, J S; Welland, M; Gass, M; Muller, K; Skepper, J; Midgley, P

2010-01-01

Functionalized single-walled carbon nanotubes (SWNTs) are currently being investigated for a variety of applications, including contrast agents for medical imaging 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 - 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.

The interaction of carbon-14 carbonate solution species with semiarid sediment

International Nuclear Information System (INIS)

Martin, W.J.

1991-10-01

14 C is a waste product that has been and may continue to be disposed and/or released into our environment. Subsurface land disposal has been considered as a means of control of nuclear waste and disposal of contaminant migration in the environment. Semiarid environments are preferred for subsurface disposal of solid and liquid wastes. However, such disposal of 14 C may potentially introduce it into the subsurface and groundwater environmental pathways. A limited amount of site-specific data have been published for 14 C transport through the subsurface and groundwater pathways. The experiments conducted in this study perform two functions: (1) they provide a specific impetus for further experimental work and (2) they give credibility to the estimated values used in environmental dose modeling. 11 refs., 1 fig., 1 tab

Quantitative carbon-14 autoradiography at the cellular level: principles and application for cell kinetic studies. [Review

Energy Technology Data Exchange (ETDEWEB)

Doermer, P [Gesellschaft fuer Strahlen- und Umweltforschung m.b.H., Muenchen (Germany, F.R.). Inst. fuer Haematologie

1981-03-01

Amounts of radio-labelled substances as low as 10/sup -18/ moles incorporated into individual cells can be measured by utilizing techniques of quantitative autoradiography. The principles and application of quantitative carbon-14 autoradiography are reviewed. Silver grain densities can be counted by automated microphotometry allowing on-line data processing by an interfaced computer. Rate measurements of /sup 14/C-thymidine incorporation into individual cells yield values of the DNA synthesis rate and the DNA synthesis time of a cell compartment can be derived. This is an essential time parameter for the evaluation of kinetic events in proliferating cell populations. This method is applicable to human cells without radiation hazard to man and provides an optimal source of detailed information on the kinetics of normal and diseased human haematopoiesis. Examples of application consist of thalassaemia, malaria infection, iron deficiency anaemia and acute myelogenous leukaemia.

Carbon-14 based determination of the biogenic fraction of industrial CO(2) emissions - application and validation.

Science.gov (United States)

Palstra, S W L; Meijer, H A J

2010-05-01

The (14)C method is a very reliable and sensitive method for industrial plants, emission authorities and emission inventories to verify data estimations of biogenic fractions of CO(2) emissions. The applicability of the method is shown for flue gas CO(2) samples that have been sampled in 1-h intervals at a coal- and wood-fired power plant and a waste incineration plant. Biogenic flue gas CO(2) fractions of 5-10% and 48-50% have been measured at the power plant and the waste incineration plant, respectively. The reliability of the method has been proven by comparison of the power plant results with those based on carbon mass input and output data of the power plant. At industrial plants with relatively low biogenic CO(2) fraction (<10%) the results need to be corrected for sampled (14)CO(2) from atmospheric air. Copyright 2009 Elsevier Ltd. All rights reserved.

AixMICADAS, the accelerator mass spectrometer dedicated to 14C recently installed in Aix-en-Provence, France

Science.gov (United States)

Bard, Edouard; Tuna, Thibaut; Fagault, Yoann; Bonvalot, Lise; Wacker, Lukas; Fahrni, Simon; Synal, Hans-Arno

2015-10-01

A compact AMS system dedicated to measuring 14C in ultra-small samples was installed at the CEREGE in Aix-en-Provence at the end of March 2014, together with an automated graphitization system. AixMICADAS operates at around 200 kV with carbon ion stripping in helium leading to a transmission of about 47%. The hybrid ion source works with graphite targets and CO2 gas. It is coupled to a versatile gas interface system that ensures stable gas measurements from different sources: a cracker for CO2 in glass ampoules, an elemental analyzer for combusting organic matter and an automated system to handle carbonate by wet chemistry. The analyses performed during the first half-year of operation show that a precision of about 2‰ is reached on modern samples of about 1 mg of carbon. Measurements of IAEA reference materials of various 14C ages show a good agreement with consensus values. Direct measurements of geological graphites indicate a machine background equivalent to an age of 68,000 years BP. AixMICADAS is thus limited solely by the 14C contamination of samples in the field and in the laboratory. The performances of the gas ion source and its gas interface system were tested with two CO2 production units: the elemental analyzer and the automated carbonate hydrolysis unit. These tests show that samples ranging between 10 and 100 μg C can produce a 12C- ion beam of the order of 10-15 μA during time spans ranging from 3 to 30 min depending on the sample mass. Coupling the automated hydrolysis system to the gas ion source of AixMICADAS, enables us to develop a method involving sequential leaching of carbonate samples with direct 14C measurements of the leached fractions and the residual sample. The main advantage is that all of steps leaching and hydrolysis are performed in the same vial for a particular sample. A sequential leaching was applied to a young carbonate sample (ca. 6600 years BP) whose 14C age agrees with previous determination and which shows no sign of

Study of intermittency of target fragments in the interactions of 28Si-Em collisions at 14.6 A GeV

International Nuclear Information System (INIS)

Ayaz Ahmad, M.; Ashraf T, M.; Ahmad, Shafiq

2008-01-01

An attempt has been made to investigate the intermittent behaviour and fractal properties of emission spectra of fast and slow target associated particles from 28 Si-emulsion interactions at 14.6 A GeV using nuclear emulsion in cosθ phase space

Abundant pre-industrial carbon detected in Canadian Arctic headwaters: implications for the permafrost carbon feedback

Science.gov (United States)

Dean, J. F.; van der Velde, Y.; Garnett, M. H.; Dinsmore, K. J.; Baxter, R.; Lessels, J. S.; Smith, P.; Street, L. E.; Subke, J.-A.; Tetzlaff, D.; Washbourne, I.; Wookey, P. A.; Billett, M. F.

2018-03-01

Mobilization of soil/sediment organic carbon into inland waters constitutes a substantial, but poorly-constrained, component of the global carbon cycle. Radiocarbon (14C) analysis has proven a valuable tool in tracing the sources and fate of mobilized carbon, but aquatic 14C studies in permafrost regions rarely detect ‘old’ carbon (assimilated from the atmosphere into plants and soil prior to AD1950). The emission of greenhouse gases derived from old carbon by aquatic systems may indicate that carbon sequestered prior to AD1950 is being destabilized, thus contributing to the ‘permafrost carbon feedback’ (PCF). Here, we measure directly the 14C content of aquatic CO2, alongside dissolved organic carbon, in headwater systems of the western Canadian Arctic—the first such concurrent measurements in the Arctic. Age distribution analysis indicates that the age of mobilized aquatic carbon increased significantly during the 2014 snow-free season as the active layer deepened. This increase in age was more pronounced in DOC, rising from 101-228 years before sampling date (a 120%-125% increase) compared to CO2, which rose from 92-151 years before sampling date (a 59%-63% increase). ‘Pre-industrial’ aged carbon (assimilated prior to ~AD1750) comprised 15%-40% of the total aquatic carbon fluxes, demonstrating the prevalence of old carbon to Arctic headwaters. Although the presence of this old carbon is not necessarily indicative of a net positive PCF, we provide an approach and baseline data which can be used for future assessment of the PCF.

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

Metabolism of [2-14C]acetate and its use in assessing hepatic Krebs cycle activity and gluconeogenesis

International Nuclear Information System (INIS)

Schumann, W.C.; Magnusson, I.; Chandramouli, V.; Kumaran, K.; Wahren, J.; Landau, B.R.

1991-01-01

To examine the fate of the carbons of acetate and to evaluate the usefulness of labeled acetate in assessing intrahepatic metabolic processes during gluconeogenesis, [2-14C]acetate, [2-14C]ethanol, and [1-14C]ethanol were infused into normal subjects fasted 60 h and given phenyl acetate. Distributions of 14C in the carbons of blood glucose and glutamate from urinary phenylacetylglutamine were determined. With [2-14C]acetate and [2-14C]ethanol, carbon 1 of glucose had about twice as much 14C as carbon 3. Carbon 2 of glutamate had about twice as much 14C as carbon 1 and one-half to one-third as much as carbon 4. There was only a small amount in carbon 5. These distributions are incompatible with the metabolism of [2-14C]acetate being primarily in liver. Therefore, [2-14C]acetate cannot be used to study Krebs cycle metabolism in liver and in relationship to gluconeogenesis, as has been done. The distributions can be explained by: (a) fixation of 14CO2 from [2-14C]acetate in the formation of the 14C-labeled glucose and glutamate in liver and (b) the formation of 14C-labeled glutamate in a second site, proposed to be muscle. [1,3-14C]Acetone formation from the [2-14C]acetate does not contribute to the distributions, as evidenced by the absence of 14C in carbons 2-4 of glutamate after [1-14C]ethanol administration

Sources of C-14 generation and associated doses

International Nuclear Information System (INIS)

Amado, Valeria A.; Biaggio, Alfredo L.; Canoba, Analia C.; Curti, Adriana R.

2009-01-01

C-14 is a radioactive isotope of C with a half-life of 5700 years that decays to N-14 by emission of beta radiation. It is naturally produced in the upper atmosphere by cosmic ray neutrons via the (n;p) reaction over N-14. Anthropogenic C-14 has been generated in the past by atmospheric nuclear weapon tests and it is currently produced during the operation of nuclear reactors. Once released this radionuclide behaves in the biosphere as the standard carbon cycle. Since the beginning of the industrial period the relationship Carbon-14/Stable Carbon has changed continuously, and so the dose incurred by the world population. In this paper the main anthropogenic activities that modified such relationship are presented and analyzed: the Suess effect and the generation of nuclear energy. It is concluded that the current trend of reduction of the total dose due to C-14 will continue during the next decades. Finally it is indicated that in order to prevent an excessive accumulation of this radionuclide in the biosphere, actions should be collectively implemented to be effective. (author) [es

An efficient synthesis of carbon-14 labelled vigabatrin

International Nuclear Information System (INIS)

Gill, H.S.

1995-01-01

Vigabatrin-[6- 14 C] ((R,S)-4-amino-5-hexenoic-[6- 14 C] acid) was synthesized by employing Wittig condensation of 1-(1-butenyl) -2-oxo-5-pyrrolidinecarboxaldehyde with methyl-[ 14 C]-triphenyl-phosphonium iodide as the key step. The synthetic sequence involved 3 steps and produced the title compound in 70% overall yield with a radiochemical purity of 100%. (author)

Synthesis of (9Z, 12E-, (9E, 12Z-[1-¹⁴C]-linoleic acid, (9Z, 12Z, 15E-, (9E, 12Z, 15Z-[1-¹⁴C]-linolenic acid and (5Z, 8Z, 11Z, 14E-[1-¹⁴C]-arachidonic acid

Directory of Open Access Journals (Sweden)

Enard, Thierry

1996-04-01

Full Text Available Trans polyunsaturated fatty acids are produced in vegetable oils during heat treatment (240-250 °C.ln order to study the metabolic pathway of 9c, 12t and 9t, 12c linoleic acid and 9c, 12c, 15t and 9t, 12c, 15c linolenic acid, these products were prepared labelled with carbon 14 in the carboxylic position. 5c, 8c, 11c, 14t-Arachidonic acid was also labelled on the carboxylic position with carbon 14 in order to study its physiological effects. To introduce the labelling (E-bromo precursors with a 17 carbons chain or a 19 carbon chain were needed. The different syntheses were done by elongation steps and creation of cis double bonds via highly stereospecific Wittig reactions. The radioactive carbon atom was introduced from [¹⁴C]-potassium cyanide. The final radioactive fatty acids had a specific activity greater than 50 mCi/mmol and a radioactive purity better than 99 % for linoleic and linolenic and better than 98.6 % for arachidonic acid.

S14 as a Therapeutic Target in Breast Cancer

Science.gov (United States)

2006-08-01

recombinant adenoviruses. The blot (25 Ag protein/lane) was probed with an antibody specific for rat S14. Lane 1— Hyperthyroid , carbohydrate-fed rat liver...to that observed in liver from a hyperthyroid rat fed a fat-free, high carbohydrate diet (lane 1). Infection with Ad-rS14 accelerated the accumulation...1]). Insight into the metabolic function of S14 came from studies of rat he- patocytes, where inhibition of its expression prevented activation of

Carbonized Micro- and Nanostructures: Can Downsizing Really Help?

Science.gov (United States)

Naraghi, Mohammad; Chawla, Sneha

2014-01-01

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. PMID:28788651

MARS14 deep-penetration calculation for the ISIS target station shielding

International Nuclear Information System (INIS)

Nakao, Noriaki; Nunomiya, Tomoya; Iwase, Hiroshi; Nakamura, Takashi

2004-01-01

The calculation of neutron penetration through a thick shield was performed with a three-dimensional multi-layer technique using the MARS14(02) Monte Carlo code to compare with the experimental shielding data in 1998 at the ISIS spallation neutron source facility of Rutherford Appleton Laboratory. In this calculation, secondary particles from a tantalum target bombarded by 800-MeV protons were transmitted through a bulk shield of approximately 3-m-thick iron and 1-m-thick concrete. To accomplish this deep-penetration calculation, a three-dimensional multi-layer technique and energy cut-off method were used considering a spatial statistical balance. Finally, the energy spectra of neutrons behind the very thick shield could be calculated down to the thermal energy with good statistics, and the calculated results typically agree well within a factor of two with the experimental data over a broad energy range. The 12 C(n,2n) 11 C reaction rates behind the bulk shield were also calculated, which agree with the experimental data typically within 60%. These results are quite impressive in calculation accuracy for deep-penetration problem

High temperature vacuum furnace for the preparation of graphite targets for 14C dating by tandem accelerator mass spectrometry

International Nuclear Information System (INIS)

Lowe, D.C.; Bristow, P.; Judd, W.J.

1985-02-01

A simple and reliable furnace design capable of producing temperatures of up to 2800 deg. C is presented. The furnace has been specifically designed for the rapid and reliable production of graphite targets for 14 C dating purposes but may be used in a variety of applications requiring high temperatures under vacuum conditions

Quantitative Analysis of Carbon Flow into Photosynthetic Products Functioning as Carbon Storage in the Marine Coccolithophore, Emiliania huxleyi.

Science.gov (United States)

Tsuji, Yoshinori; Yamazaki, Masatoshi; Suzuki, Iwane; Shiraiwa, Yoshihiro

2015-08-01

The bloom-forming coccolithophore Emiliania huxleyi (Haptophyta) is a dominant marine phytoplankton, cells of which are covered with calcareous plates (coccoliths). E. huxleyi produces unique lipids of C37-C40 long-chain ketones (alkenones) with two to four trans-unsaturated bonds, β-glucan (but not α-glucan) and acid polysaccharide (AP) associated with the morphogenesis of CaCO3 crystals in coccoliths. Despite such unique features, there is no detailed information on the patterns of carbon allocation into these compounds. Therefore, we performed quantitative estimation of carbon flow into various macromolecular products by conducting (14)C-radiotracer experiments using NaH(14)CO3 as a substrate. Photosynthetic (14)C incorporation into low molecular-mass compounds (LMC), extracellular AP, alkenones, and total lipids except alkenones was estimated to be 35, 13, 17, and 25 % of total (14)C fixation in logarithmic growth phase cells and 33, 19, 18, and 18 % in stationary growth phase cells, respectively. However, less than 1 % of (14)C was incorporated into β-glucan in both cells. (14)C-mannitol occupied ca. 5 % of total fixed (14)C as the most dominant LMC product. Levels of all (14)C compounds decreased in the dark. Therefore, alkenones and LMC (including mannitol), but not β-glucan, function in carbon/energy storage in E. huxleyi, irrespective of the growth phase. Compared with other algae, the low carbon flux into β-glucan is a unique feature of carbon metabolism in E. huxelyi.

An efficient synthesis of carbon-14 labelled vigabatrin

Energy Technology Data Exchange (ETDEWEB)

Gill, H.S. [Marion Merrell Dow Research Inst., Cincinnati, OH (United States)

1995-12-31

Vigabatrin-[6-{sup 14}C] ((R,S)-4-amino-5-hexenoic-[6-{sup 14}C] acid) was synthesized by employing Wittig condensation of 1-(1-butenyl) -2-oxo-5-pyrrolidinecarboxaldehyde with methyl-[{sup 14}C]-triphenyl-phosphonium iodide as the key step. The synthetic sequence involved 3 steps and produced the title compound in 70% overall yield with a radiochemical purity of 100%. (author).

14C Analysis of protein extracts from Bacillus spores.

Science.gov (United States)

Cappuccio, Jenny A; Falso, Miranda J Sarachine; Kashgarian, Michaele; Buchholz, Bruce A

2014-07-01

Investigators of bioagent incidents or interdicted materials need validated, independent analytical methods that will allow them to distinguish between recently made bioagent samples versus material drawn from the archives of a historical program. Heterotrophic bacteria convert the carbon in their food sources, growth substrate or culture media, into the biomolecules they need. The F(14)C (fraction modern radiocarbon) of a variety of media, Bacillus spores, and separated proteins from Bacillus spores was measured by accelerator mass spectrometry (AMS). AMS precisely measures F(14)C values of biological materials and has been used to date the synthesis of biomaterials over the bomb pulse era (1955 to present). The F(14)C of Bacillus spores reflects the radiocarbon content of the media in which they were grown. In a survey of commercial media we found that the F(14)C value indicated that carbon sources for the media were alive within about a year of the date of manufacture and generally of terrestrial origin. Hence, bacteria and their products can be dated using their (14)C signature. Bacillus spore samples were generated onsite with defined media and carbon free purification and also obtained from archived material. Using mechanical lysis and a variety of washes with carbon free acids and bases, contaminant carbon was removed from soluble proteins to enable accurate (14)C bomb-pulse dating. Since media is contemporary, (14)C bomb-pulse dating of isolated soluble proteins can be used to distinguish between historical archives of bioagents and those produced from recent media. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effect of HF leaching on {sup 14}C dates of pottery

Energy Technology Data Exchange (ETDEWEB)

Goslar, Tomasz, E-mail: goslar@radiocarbon.pl [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznan (Poland); Poznan Radiocarbon Laboratory, ul. Rubiez 46, 61-612 Poznan (Poland); Kozlowski, Janusz [Institute of Archaeology, Jagiellonian University, ul. Golebia 11, 30-007 Krakow (Poland); Szmyt, Marzena [Institute for Eastern Studies, Adam Mickiewicz University, ul. 28 Czerwca 1956 nr 198, 61-486 Poznan (Poland); Czernik, Justyna [Poznan Radiocarbon Laboratory, ul. Rubiez 46, 61-612 Poznan (Poland)

2013-01-15

This paper presents the experiments with {sup 14}C dating of two potsherds, which contained carbon dispersed rather homogeneously in their clay fabric. After AAA treatment, the potsherds still appeared to be contaminated with young carbon, presumably connected with humic acids. To make removal of humic acids more effective, we treated the sherds with HF acid of different concentration. The {sup 14}C results obtained demonstrate that HF treatment indeed helps to remove humic contaminants, but it also mobilizes carbon bound to raw clay, which may make {sup 14}C dates too old. We conclude therefore, that using a simple combination of HF and AAA treatment seems insufficient in reliable {sup 14}C dating of carbon homogeneously dispersed in the volume of potsherds.

Analysis of 14C level around Qinshan NPP base

International Nuclear Information System (INIS)

Huang Renjie; Liang Haiyan; Chen Qianyuan; Ni Shiying; He Jun; Zeng Guangjian; Ma Yongfu

2012-01-01

By using the method of alkaline solution absorption, the activity concentrations of Carbon-14 as well as its variation tendency in air and biological samples were analyzed. The air samples and biological samples were collected around the Qinshan nuclear power plant base (Qinshan NPP Base) in 2002 to 2009 and 2007 to 2009 respectively. The results showed that, since 2002, the annual average activity concentrations of Carbon-14 in air samples were in the range of 38.3 mBq/m 3 to 55.4 mBq/m 3 . Although the monitoring results of Xiajiawan village and Yanliucun village were comparatively higher than the reference site in Hangzhou City, the results were still at the same level. Meanwhile, monitoring results of Xiajiawan village and Yangliucun village in the summer of 2004 and 2005 are relatively high, with the peak value of 55.4 mBq/m 3 appeared in Xiajiawan village during the summer of 2005. Correspondingly the annual airborne Carbon-14 of 2004 and 2005 discharged from the Qinshan NPP 3 rd Phase were higher than normal as well, it can therefore be concluded that the activity concentration of Carbon-14 around the Qinshan NPP Base are related to the discharged source term. The activity concentration of Carbon-14 in rice and leaf vegetable samples from Xiajiawan village and Yangliucun village were slightly higher, but within the same level, than that of Hangzhou. The activity concentration of Carbon-14 in the mullet samples collected from the sea area around Qinshan NPP Base are approximately the same with the sea area of Zhoushan. (authors)

Detection of 14C in natural trace organics recovered from groundwater

International Nuclear Information System (INIS)

Murphy, E.; Long, A.; Davis, S.N.; Donahue, D.

1985-01-01

Radiocarbon measurements on dissolved inorganic carbon (DIC) in groundwater have given the authors insight into chemical and hydrological processes occurring in aquifers. Carbon-14 analyses on various dissolved organic carbon (DOC) fractions from groundwater are only starting, but, as is true for DIC 14 C measurements, their significance reaches beyond dating of water and into chemical processes in the aquifer and recharge zone. When combined with information on the chemical character of the DOC, 14 C data may clarify the origin and diagenesis of organic carbon in groundwater. In the past, research into the 14 C has been discouraged by the low concentrations of DOC in groundwater, typically in the μg/l range. The tandem accelerator at the University of Arizona can analyze 14 C in as little as 1 mg of carbon, thus requiring isolation of the DOC from 200 l or less of groundwater. This paper describes the techniques bring used for separation of the DOC in groundwater, some of the data collected, and the significance of these data

Quantification of Helicobacter pylori infection in gastritis and ulcer disease using a simple and rapid carbon-14-urea breath test

International Nuclear Information System (INIS)

Debongnie, J.C.; Pauwels, S.; Raat, A.; de Meeus, Y.; Haot, J.; Mainguet, P.

1991-01-01

Gastric urease was studied isotopically in 230 patients with biopsy-proven normal mucosa or chronic gastritis, including 59 patients with ulcer disease. Carbon-14-urea was given in 25 ml of water without substrate carrier or nutrient-dense meal, and breath samples were collected over a 60-min period. The amount of 14CO2 excreted at 10 min was independent of the rate of gastric emptying and was not quantitatively influenced by the buccal urease activity. The 10-min 14CO2 values discriminated well between Helicobacter pylori positive and negative patients (94% sensitivity, 89% specificity) and correlated with the number of organisms assessed by histology. The test was a good predictor of chronic gastritis (95% sensitivity and 96% specificity), and a quantitative relationship was observed between 14CO2 values and the severity and activity of the gastritis. In H. pylori positive patients, breath 14CO2 was found to be similar in patients with and without ulcer disease, suggesting that the number of bacteria is not a determining factor for the onset of ulceration

Quantification of Helicobacter pylori infection in gastritis and ulcer disease using a simple and rapid carbon-14-urea breath test

Energy Technology Data Exchange (ETDEWEB)

Debongnie, J.C.; Pauwels, S.; Raat, A.; de Meeus, Y.; Haot, J.; Mainguet, P. (Department of Nuclear Medicine, University of Louvain Medical School, Brussels (Belgium))

1991-06-01

Gastric urease was studied isotopically in 230 patients with biopsy-proven normal mucosa or chronic gastritis, including 59 patients with ulcer disease. Carbon-14-urea was given in 25 ml of water without substrate carrier or nutrient-dense meal, and breath samples were collected over a 60-min period. The amount of 14CO2 excreted at 10 min was independent of the rate of gastric emptying and was not quantitatively influenced by the buccal urease activity. The 10-min 14CO2 values discriminated well between Helicobacter pylori positive and negative patients (94% sensitivity, 89% specificity) and correlated with the number of organisms assessed by histology. The test was a good predictor of chronic gastritis (95% sensitivity and 96% specificity), and a quantitative relationship was observed between 14CO2 values and the severity and activity of the gastritis. In H. pylori positive patients, breath 14CO2 was found to be similar in patients with and without ulcer disease, suggesting that the number of bacteria is not a determining factor for the onset of ulceration.

C -14 analysis in radioactive waste by combustion and digestion techniques

International Nuclear Information System (INIS)

Venescu, R. E.; Valeca, M.; Bujoreanu, L.; Bujoreanu, D.; Venescu, B.

2016-01-01

Carbon-14 is a long lived radionuclide (half life of 5730 years) present in almost all radioactive waste streams generated by a CANDU nuclear power plant. It is a pure beta emitter that decays to 14N by emitting low energy beta-radiation with an average energy of 49.5keV and a maximum energy of 156keV. Before the beta radiation of 14C can be measured from radioactive waste liquid scintillation counting (LSC), the samples must be transformed in a stable, clear and homogeneous solution. Two methods were tested for carbon-14 recovery and analysis in radioactive wastes from nuclear power plants. The combustion process is a simple automatic method of sample preparation, in which all carbon isotopes, including 14C are oxidized to gaseous carbon dioxide that is subsequently trapped in form of carbonate in a column filled with a carbon dioxide absorbent. The microwave digestion is the method wherein the samples are transformed totally or partially in liquid phase depending on the sample matrix using adequate digestion reagents. The samples were counted with a normal and low level count mode liquid scintillation counter Tri-Carb3110TR. The tests performed on the simulated radwaste showed a 14C recovery of 90% by combustion and higher than 75% by microwave digestion method. (authors)

The preparation of glucosa uniformly labelled with carbon-14

International Nuclear Information System (INIS)

Garcia Pineda, D.; Suarez, C.; Rodrigo Gonzalez, E.

1978-01-01

The plant, (Zea mais, L) and culture conditions for an optimun production of glucose has been chosen. To achieve the labelling of glucose, photosynthesis and carboxilation are carried on under an artificial atmosphere of 1 4CO 2 produced from 1 4C-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 radiactivity is determined in each of its carbon atoms. (author)

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

International Nuclear Information System (INIS)

Paula Eduardo, B. de; Cerri, C.C.

1988-01-01

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.) [pt

S14 as a Therapeutic Target in Breast Cancer

National Research Council Canada - National Science Library

Kinlaw, William

2004-01-01

.... Our aims are first to develop a model of anti-S14 breast cancer therapy in mice. Intratumoral adenoviral delivery of an S14-antisense gene into human breast cancer cell xenografts caused a significant inhibition of tumor growth...

Discharge runaway in high power impulse magnetron sputtering of carbon: the effect of gas pressure, composition and target peak voltage

Science.gov (United States)

Vitelaru, Catalin; Aijaz, Asim; Constantina Parau, Anca; Kiss, Adrian Emil; Sobetkii, Arcadie; Kubart, Tomas

2018-04-01

Pressure and target voltage driven discharge runaway from low to high discharge current density regimes in high power impulse magnetron sputtering of carbon is investigated. The main purpose is to provide a meaningful insight of the discharge dynamics, with the ultimate goal to establish a correlation between discharge properties and process parameters to control the film growth. This is achieved by examining a wide range of pressures (2–20 mTorr) and target voltages (700–850 V) and measuring ion saturation current density at the substrate position. We show that the minimum plasma impedance is an important parameter identifying the discharge transition as well as establishing a stable operating condition. Using the formalism of generalized recycling model, we introduce a new parameter, ‘recycling ratio’, to quantify the process gas recycling for specific process conditions. The model takes into account the ion flux to the target, the amount of gas available, and the amount of gas required for sustaining the discharge. We show that this parameter describes the relation between the gas recycling and the discharge current density. As a test case, we discuss the pressure and voltage driven transitions by changing the gas composition when adding Ne into the discharge. We propose that standard Ar HiPIMS discharges operated with significant gas recycling do not require Ne to increase the carbon ionization.

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.

Hexon and fiber of adenovirus type 14 and 55 are major targets of neutralizing antibody but only fiber-specific antibody contributes to cross-neutralizing activity.

Science.gov (United States)

Feng, Ying; Sun, Xikui; Ye, Xianmiao; Feng, Yupeng; Wang, Jinlin; Zheng, Xuehua; Liu, Xinglong; Yi, Changhua; Hao, Mingli; Wang, Qian; Li, Feng; Xu, Wei; Li, Liang; Li, Chufang; Zhou, Rong; Chen, Ling; Feng, Liqiang

2018-05-01

Re-emerging human adenoviruses type 14 (HAdV14) and 55 (HAdV55) represent two highly virulent adenoviruses. The neutralizing antibody (nAb) responses elicited by infection or immunization remain largely unknown. Herein, we generated hexon-chimeric HAdV14 viruses harboring each single or entire hexon hyper-variable-regions (HVR) from HAdV55, and determined the neutralizing epitopes of human and mouse nAbs. In human sera, hexon-targeting nAbs are type-specific and mainly recognize HVR2, 5, and 7. Fiber-targeting nAbs are only detectable in sera cross-neutralizing HAdV14 and HAdV55 and contribute substantially to cross-neutralization. Penton-binding antibodies, however, show no significant neutralizing activities. In mice immunized with HAdV14 or HAdV55, a single immunization mainly elicited hexon-specific nAbs, which recognized HAdV14 HVR1, 2, and 7 and HAdV55 HVR1 and 2, respectively. After a booster immunization, cross-neutralizing fiber-specific nAbs became detectable. These results indicated that hexon elicits type-specific nAbs whereas fiber induces cross-neutralizing nAbs to HAdV14 and HAdV55, which are of significance in vaccine development. Copyright © 2018 Elsevier Inc. All rights reserved.

Preparation of a lipopolysaccharide from ''Escherichia coli 0111a, 0111b, K58: H21'' bacterial wall, labeled with carbon-14

International Nuclear Information System (INIS)

Garcia Pineda, D.; Solano, M.A.

1980-01-01

A brief description is made of the morphological and chemical structure of lipopolysaccharides, as well as its occurence in nature and its mechanisms of action. It is emphasized the usefulness of the labelled lipopolysaccharide for actual biochemical and biomedical research. The method for the labelling, isolation and purification of carbon-14 lipopolysaccharide is described. (auth.)

Carbon 14 absorption and translocation in sugar cane

International Nuclear Information System (INIS)

Pimentel, R.M.M.; Sampaio, E.V.S.; Salcedo, I.H.

1990-01-01

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)

Cambrian-lower Middle Ordovician passive carbonate margin, southern Appalachians: Chapter 14

Science.gov (United States)

Read, J. Fred; Repetski, John E.

2012-01-01

The southern Appalachian part of the Cambrian–Ordovician passive margin succession of the great American carbonate bank extends from the Lower Cambrian to the lower Middle Ordovician, is as much as 3.5 km (2.2 mi) thick, and has long-term subsidence rates exceeding 5 cm (2 in.)/k.y. Subsiding depocenters separated by arches controlled sediment thickness. The succession consists of five supersequences, each of which contains several third-order sequences, and numerous meter-scale parasequences. Siliciclastic-prone supersequence 1 (Lower Cambrian Chilhowee Group fluvial rift clastics grading up into shelf siliciclastics) underlies the passive margin carbonates. Supersequence 2 consists of the Lower Cambrian Shady Dolomite–Rome-Waynesboro Formations. This is a shallowing-upward ramp succession of thinly bedded to nodular lime mudstones up into carbonate mud-mound facies, overlain by lowstand quartzose carbonates, and then a rimmed shelf succession capped by highly cyclic regressive carbonates and red beds (Rome-Waynesboro Formations). Foreslope facies include megabreccias, grainstone, and thin-bedded carbonate turbidites and deep-water rhythmites. Supersequence 3 rests on a major unconformity and consists of a Middle Cambrian differentiated rimmed shelf carbonate with highly cyclic facies (Elbrook Formation) extending in from the rim and passing via an oolitic ramp into a large structurally controlled intrashelf basin (Conasauga Shale). Filling of the intrashelf basin caused widespread deposition of thin quartz sandstones at the base of supersequence 4, overlain by widespread cyclic carbonates (Upper Cambrian lower Knox Group Copper Ridge Dolomite in the south; Conococheague Formation in the north). Supersequence 5 (Lower Ordovician upper Knox in the south; Lower to Middle Ordovician Beekmantown Group in the north) has a basal quartz sandstone-prone unit, overlain by cyclic ramp carbonates, that grade downdip into thrombolite grainstone and then storm

Targeting progesterone metabolism in breast cancer with l-proline derived new 14-azasteroids.

Science.gov (United States)

Singh, Jyotsana; Singh, Ritesh; Gupta, Preeti; Rai, Smita; Ganesher, Asha; Badrinarayan, Preethi; Sastry, G Narahari; Konwar, Rituraj; Panda, Gautam

2017-08-15

Breast cancer cell proliferation is promoted by a variety of mitogenic signals. Classically estrogen is considered as most predominant mitogenic signal in hormone-dependent breast cancer and progesterone is primarily considered to have protective effect. However, it is suggested that some progesterone metabolite may promote breast cancer and progesterone metabolites like 5α-pregnane and 4-pregnene could serve as regulators of estrogen-responsiveness of breast cancer cells. Here, we estimated the potential of alternate targeting of breast cancer via progesterone signalling. l-Proline derived novel 14-azasteroid compounds were screened against MCF-7 and MDA-MB-231 cell lines using MTT assay. In silico studies, cell cycle, Annexin-V-FITC/PI, JC-1 mitochondrial assay, ROS analysis were performed to analyse the impact of hit compound 3b on breast cancer cells. Further, we analysed the impact of hit 3b on the progesterone, its metabolites and enzymes responsible for the conversion of progesterone and its metabolites using ELISA. Data suggests that compound 3b binds and down regulates of 5α-reductase by specifically inhibiting production of progesterone metabolites that are capable of promoting breast cancer proliferation, epithelial mesenchymal transition and migration. This study establishes the proof of concept and generation of new leads for additional targeting of breast cancer. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

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

Immobilization of carbon-14 from reactor graphite waste by use of self-sustaining reaction in the C-Al-TiO2 system

International Nuclear Information System (INIS)

Karlina, O.K.; Klimov, V.L.; Ojovan, M.I.; Pavlova, G.Yu.; Dmitriev, S.A.; Yurchenko, A.Yu.

2005-01-01

As a result of long-term neutron irradiation, the long-lived 14 C is produced in the reactor graphite. The exothermic self-sustaining reaction 3C(graphite) + 4Al + 3TiO 2 = 3TiC + 2Al 2 O 3 was proposed for processing of such waste. In doing so, the carbon, including the 14 C, is chemically bound in the stable TiC. The reaction products in the C-Al-TiO 2 system were investigated both by thermodynamic simulation and experimentally in the course of this work

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.

Laser ablation for the synthesis of carbon nanotubes

Science.gov (United States)

Holloway, Brian C.; Eklund, Peter C.; Smith, Michael W.; Jordan, Kevin C.; Shinn, Michelle

2010-04-06

Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces an output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

Laser ablation for the synthesis of carbon nanotubes

Science.gov (United States)

Holloway, Brian C. (Inventor); Eklund, Peter C. (Inventor); Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor); Shinn, Michelle (Inventor)

2012-01-01

Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces and output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

SU-E-J-142: Prompt Gamma Emission Measurements From a Passively Scattered Proton Beam On Targets Containing 16O, 12C and 14N

Energy Technology Data Exchange (ETDEWEB)

Jeyasugiththan, J [Department of Physics, University of Cape Town, Cape Town (South Africa); Department of Clinical Oncology, Teaching Hospital, Jeffna (Sri Lanka); Peterson, S [Department of Physics, University of Cape Town, Cape Town (South Africa)

2015-06-15

Purpose: To measure the prompt gamma emission from the important elements found in tissue ({sup 16}O,{sup 12}C and {sup 14}N) in a clinical passive-scatter treatment environment. Methods: The targets (composed of water, Perspex, graphite and liquid nitrogen) were irradiated with a 200 MeV passive-scatter proton beam and the discrete prompt gamma energy spectra was detected by a high resolution 2′ × 2′ LaBr. detector. In order to reduce the high level of radiation produced by the beam line elements, the detector was surrounded by 10 cm of lead to attenuate the scattered gamma-rays entering the detector with an extra 5 cm thick layer of lead added along the beam direction. A 10 cm thick collimator with a 5 cm × 10 cm rectangular opening was also used. Results: The prompt gamma peaks at 6.13 MeV and 4.44 MeV were clearly identified as a Result of the inelastic nuclear reaction between the protons and the 16O atoms found in the water target. The 6.13 MeV peak was 5% higher than the peak at 4.44 MeV for the water target. The 4.44 MeV peak was the only identified emission in the prompt gamma energy spectra from the graphite target ({sup 12}C). The expected 2.313 MeV peak form the{sup 14}N (liquid nitrogen target) was identified, but the other expected {sup 14}N peaks could not be resolved. Conclusion: Prompt gamma measurements with a passive-scatter proton beam are possible, but the presence of a high amount of background radiation from the patient final collimator presents a challenge at the treatment isocenter. The prominent prompt gamma peaks at 6.13 MeV and 4.44 MeV were identified from the water, Perspex and graphite targets. The prompt gammas from the liquid nitrogen target were difficult to see, but may not be significant in the in-vivo verification process.

Detection and Investigation of Carbon Ions Induced by Nd:YAG laser using SSNTDs

International Nuclear Information System (INIS)

Qindeel, Rabia; Ali, Jalil Bin; Chaudhary, K. T.; Hussain, M. S.

2011-01-01

A Q-Switched Nd:YAG laser pulse of pulsed width of 9∼14 ns, wavelength of 1064 nm, repetition rate of 0.5 Hz, power of 1.1 MW and energy of 10 mJ has been used to ablate the 4N pure graphite target through IR lens. Solid state nuclear track detector (SSNTD) CR-39 has been used to calculate the energy of carbon ions produced as a result of laser ablation and the whole experiment has been performed under pressure ∼10 -3 Torr in stainless steel vacuum chamber. The minimum and maximum energy of carbon ions observed are 0.2 KeV to 250 KeV respectively.

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.

Syntheses of (6- sup 14 C) and (5-carboxy, 6- sup 14 C sub 2 )nitrendipine

Energy Technology Data Exchange (ETDEWEB)

Maul, N.; Scherling, D. (Bayer AG, Wuppertal (Germany, F.R.). Inst. fuer Pharmakologie)

1989-04-01

(6-{sup 14}C)Nitrendipine synthesis started from barium({sup 14})carbonate, which was converted to (1-{sup 14}C)acetyl chloride. The acid chloride was condensed with Meldrum's acid (2,2-dimethyl-1,3-dioxane-4,6-dione). The resulting intermediate was treated with boiling methanol to give methyl (3-{sup 14}C)acetoacetate. The reaction with gaseous ammonia in toluene yielded the corresponding methyl 3-amino(3-{sup 14}C)crotonate which was condensed with ethyl 2-(3-nitro-benzylidene) acetoacetate to obtain (6-{sup 14}C)nitrendipine. (author).

Degradation of multiwall carbon nanotubes by bacteria

International Nuclear Information System (INIS)

Zhang, Liwen; Petersen, Elijah J.; Habteselassie, Mussie Y.; Mao, Liang; Huang, Qingguo

2013-01-01

Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading 14 C-labeled MWCNTs into 14 CO 2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia. This result suggests that microbe/MWCNTs interaction may impact the long-term fate of MWCNTs. Highlights: •Mineralization of MWCNTs by a bacterial community was observed. •The mineralization required an external carbon source. •Multiple intermediate products were identified in the MWCNT degrading culture. •Three bacterial species were found likely responsible for MWCNT degradation. -- The 14 C-labeled multiwall carbon nanotubes can be degraded to 14 CO 2 and other byproducts by a bacteria community under natural conditions

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

Science.gov (United States)

Yui, Satoru; Nakatani, Yuichi; Hunter, Michael J; Chazin, Walter J; Yamazaki, Masatoshi

2002-06-01

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. The present study was undertaken to elucidate which subunit is responsible for the apoptosis-inducing activity, and to explore the mechanism of zinc-reversible apoptosis induction. The apoptosis-inducing activity of recombinant human MRP8 (rhMRP8) and recombinant human MRP14 (rhMRP14) was examined against EL-4 lymphoma cells in vitro. To determine whether zinc deprivation by calprotectin was essential for the cytotoxicity, the activity of calprotectin was tested under conditions where physical contact between the factor and the cells was precluded by a low molecular weight cut-off dialysis membrane. The cytotoxicity of rhMRP14 against EL-4 cells was first detected at 10 microM in a standard medium, whereas rhMRP8 caused only marginal cytotoxicity at 40 microM. A mixture of both proteins showed higher specific activity (onset of cytotoxicity at 5 microM). When the cells were cultured in divalent cation-depleted medium, each dose-response curve was shifted to about a four-fold lower concentration range. Calprotectin was found to induce cell death even when the complex and the target cells were separated by dialysis membrane. A membrane-impermeable zinc chelator, diethylenetriamine pentaacetic acid (DTPA), also induced target cell apoptosis in a similar time-course as calprotectin. Moreover, the activities of calprotectin and DTPA were completely inhibited by the presence of zinc ions. These data indicate that calprotectin has higher specific activity to induce apoptosis than the Individual subunits, and that the mechanism is exclusion of zinc

Radiolytic decomposition of organic C-14 released from TRU waste

International Nuclear Information System (INIS)

Kani, Yuko; Noshita, Kenji; Kawasaki, Toru; Nishimura, Tsutomu; Sakuragi, Tomofumi; Asano, Hidekazu

2007-01-01

It has been found that metallic TRU waste releases considerable portions of C-14 in the form of organic molecules such as lower molecular weight organic acids, alcohols and aldehydes. Due to the low sorption ability of organic C-14, it is important to clarify the long-term behavior of organic forms under waste disposal conditions. From investigations on radiolytic decomposition of organic carbon molecules into inorganic carbonic acid, it is expected that radiation from TRU waste will decompose organic C-14 into inorganic carbonic acid that has higher adsorption ability into the engineering barriers. Hence we have studied the decomposition behavior of organic C-14 by gamma irradiation experiments under simulated disposal conditions. The results showed that organic C-14 reacted with OH radicals formed by radiolysis of water, to produce inorganic carbonic acid. We introduced the concept of 'decomposition efficiency' which expresses the percentage of OH radicals consumed for the decomposition reaction of organic molecules in order to analyze the experimental results. We estimated the effect of radiolytic decomposition on the concentration of organic C-14 in the simulated conditions of the TRU disposal system using the decomposition efficiency, and found that the concentration of organic C-14 in the waste package will be lowered when the decomposition of organic C-14 by radiolysis was taken into account, in comparison with the concentration of organic C-14 without radiolysis. Our prediction suggested that some amount of organic C-14 can be expected to be transformed into the inorganic form in the waste package in an actual system. (authors)

In-phantom dosimetry using the 13C(d,n)14N reaction for BNCT (boron neutron capture therapy)

International Nuclear Information System (INIS)

Burlon, Alejandro; Kreiner, Andres J.; White, S.; Blackburn, B.; Gierga, David; Yanch, Jacquelyn C.

2000-01-01

The use of the 13 C(d,n) 14 N reaction at E d =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)

Yucca Mountain Area Saturated Zone Dissolved Organic Carbon Isotopic Data

International Nuclear Information System (INIS)

Thomas, James; Decker, David; Patterson, Gary; Peterman, Zell; Mihevc, Todd; Larsen, Jessica; Hershey, Ronald

2007-01-01

Groundwater samples in the Yucca Mountain area were collected for chemical and isotopic analyses and measurements of water temperature, pH, specific conductivity, and alkalinity were obtained at the well or spring at the time of sampling. For this project, groundwater samples were analyzed for major-ion chemistry, deuterium, oxygen-18, and carbon isotopes of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). The U.S. Geological Survey (USGS) performed all the fieldwork on this project including measurement of water chemistry field parameters and sample collection. The major ions dissolved in the groundwater, deuterium, oxygen-18, and carbon isotopes of dissolved inorganic carbon (DIC) were analyzed by the USGS. All preparation and processing of samples for DOC carbon isotopic analyses and geochemical modeling were performed by the Desert Research Institute (DRI). Analysis of the DOC carbon dioxide gas produced at DRI to obtain carbon-13 and carbon-14 values was conducted at the University of Arizona Accelerator Facility (a NSHE Yucca Mountain project QA qualified contract facility). The major-ion chemistry, deuterium, oxygen-18, and carbon isotopes of DIC were used in geochemical modeling (NETPATH) to determine groundwater sources, f ow paths, mixing, and ages. The carbon isotopes of DOC were used to calculate groundwater ages that are independent of DIC model corrected carbon-14 ages. The DIC model corrected carbon-14 calculated ages were used to evaluate groundwater travel times for mixtures of water including water beneath Yucca Mountain. When possible, groundwater travel times were calculated for groundwater flow from beneath Yucca Mountain to down gradient sample sites. DOC carbon-14 groundwater ages were also calculated for groundwaters in the Yucca Mountain area. When possible, groundwater travel times were estimated for groundwater flow from beneath Yucca Mountain to down gradient groundwater sample sites using the DOC calculated

Oesophageal heat exchangers with a diameter of 11mm or 14.7mm are equally effective and safe for targeted temperature management.

Directory of Open Access Journals (Sweden)

Daniel C Schroeder

Full Text Available Targeted temperature management (TTM is widely used in critical care settings for conditions including hepatic encephalopathy, hypoxic ischemic encephalopathy, meningitis, myocardial infarction, paediatric cardiac arrest, spinal cord injury, traumatic brain injury, ischemic stroke and sepsis. Furthermore, TTM is a key treatment for patients after out-of-hospital cardiac-arrest (OHCA. However, the optimal cooling method, which is quick, safe and cost-effective still remains controversial. Since the oesophagus is adjacent to heart and aorta, fast heat-convection to the central blood-stream could be achieved with a minimally invasive oesophageal heat exchanger (OHE. To date, the optimal diameter of an OHE is still unknown. While larger diameters may cause thermal- or pressure-related tissue damage after long-term exposure to the oesophageal wall, smaller diameter (e.g., gastric tubes, up to 11mm may not provide effective cooling rates. Thus, the objective of the study was to compare OHE-diameters of 11mm (OHE11 and 14.7mm (OHE14.7 and their effects on tissue and cooling capability.Pigs were randomized to OHE11 (N = 8 or OHE14.7 (N = 8. After cooling, pigs were maintained at 33°C for 1 hour. After 10h rewarming, oesophagi were analyzed by means of histopathology. The oesophagus of four animals from a separate study that underwent exactly the identical preparation and cooling protocol described above but received a maintenance period of 24h were used as histopathological controls.Mean cooling rates were 2.8±0.4°C°C/h (OHE11 and 3.0±0.3°C °C/h (OHE14.7; p = 0.20. Occasional mild acute inflammatory transepithelial infiltrates were found in the cranial segment of the oesophagus in all groups including controls. Deviations from target temperature were 0.1±0.4°C (OHE11 and 0±0.1°C (OHE14.7; p = 0.91. Rewarming rates were 0.19±0.07°C °C/h (OHE11 and 0.20±0.05°C °C/h (OHE14.7; p = 0.75.OHE with diameters of 11 mm and 14.7 mm achieve

Understanding the carbon cycle in a Late Quaternary-age limestone aquifer system using radiocarbon of dissolved inorganic and organic carbon

Science.gov (United States)

Bryan, Eliza; Meredith, Karina T.; Baker, Andy; Andersen, Martin S.; Post, Vincent E. A.

2017-04-01

Estimating groundwater residence time is critical for our understanding of hydrogeological systems, for groundwater resource assessments and for the sustainable management of groundwater resources. Due to its capacity to date groundwater up to 30 thousand years old, as well as the ubiquitous nature of dissolved carbon (as organic and inorganic forms) in groundwater, 14C is the most widely used radiogenic dating technique in regional aquifers. However, the geochemistry of carbon in groundwater systems includes interaction with the atmosphere, biosphere and geosphere, which results in multiple sources and sinks of carbon that vary in time and space. Identifying these sources of carbon and processes relating to its release or removal is important for understanding the evolution of the groundwater and essential for residence time calculations. This study investigates both the inorganic and organic facets of the carbon cycle in groundwaters throughout a freshwater lens and mixing zone of a carbonate island aquifer and identifies the sources of carbon that contribute to the groundwater system. Groundwater samples were collected from shallow (5-20 m) groundwater wells on a small carbonate Island in Western Australia in September 2014 and analysed for major and minor ions, stable water isotopes (SWIs: δ18O, δ2H), 3H, 14C and 13C carbon isotope values of both DIC and DOC, and 3H. The composition of groundwater DOC was investigated by Liquid Chromatography-Organic Carbon Detection (LC-OCD) analysis. The presence of 3H (0.12 to 1.35 TU) in most samples indicates that groundwaters on the Island are modern, however the measured 14CDIC values (8.4 to 97.2 pmc) suggest that most samples are significantly older due to carbonate dissolution and recrystallisation reactions that are identified and quantified in this work. 14CDOC values (46.6 to 105.6 pMC) were higher than 14CDIC values and were well correlated with 3H values, however deeper groundwaters had lower 14CDOC values than

Computational design of high efficiency release targets for use at ISOL facilities

CERN Document Server

Liu, Y

1999-01-01

This report describes efforts made at the Oak Ridge National Laboratory to design high-efficiency-release targets that simultaneously incorporate the short diffusion lengths, high permeabilities, controllable temperatures, and heat-removal properties required for the generation of useful radioactive ion beam (RIB) intensities for nuclear physics and astrophysics research using the isotope separation on-line (ISOL) technique. Short diffusion lengths are achieved either by using thin fibrous target materials or by coating thin layers of selected target material onto low-density carbon fibers such as reticulated-vitreous-carbon fiber (RVCF) or carbon-bonded-carbon fiber (CBCF) to form highly permeable composite target matrices. Computational studies that simulate the generation and removal of primary beam deposited heat from target materials have been conducted to optimize the design of target/heat-sink systems for generating RIBs. The results derived from diffusion release-rate simulation studies for selected t...