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Sample records for highly sensitive 14c

  1. High sensitivity spectroscopy with tunable diode lasers - detection of O2 quadrupole transitions and 14C

    International Nuclear Information System (INIS)

    Reid, J.

    1981-01-01

    In recent years, tunable lead-salt diode lasers (TDLs) have found widespread application in all fields of infrared spectroscopy. However, most applications of TDLs utilise only the tunability and high resolution of these devices, and few experiments have employed the ability of the TDL to detect very small absorption coefficients. We have developed a laser absorption spectrometer (LAS) which can detect absorption coefficients as small as 10 -6 to 10 -7 m -1 , while retaining the full tunability and resolution of the TDL. This instrument has been used as a point monitoring system for many trace gases of atmospheric significance. In this paper, we describe two additional applications of the LAS: (I) the detection of very weak transitions such as quadrupole lines in oxygen, and (II) the detection of rare isotopes, with 14 C in CO 2 as an example. Details are given in the following sections. (orig.)

  2. The development of a high performance liquid chromatograph with a sensitive on-stream radioactivity monitor for the analysis of 3H- and 14C-labelled gibberellins

    International Nuclear Information System (INIS)

    Reeve, D.R.; Yokota, T.; Nash, L.; Crozier, A.

    1976-01-01

    The development of a high performance liquid chromatograph for the separation of gibberellins is described. The system combines high efficiency, peak capacity, and sample capacity with rapid speed of analysis. In addition, the construction details of a sensitive on-stream radioactivity monitor are outlined. The overall versatility of the chromatograph has been demonstrated by the separation of a range of 3 H- and 14 C-labelled gibberellins and gibberellin precursors. The system also has considerable potential for the analysis of abscisic acid and acidic and neutral indoles. (author)

  3. Detection, concentrations and distribution of paxilline, an animal neurotoxin, in mouse brain: an application of ultra-high sensitivity detection of 14C by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Roberts, P.B.; Kim, K.

    1999-01-01

    Full text: Paxilline is an intermediate in the biosynthesis of lolitrem neurotoxins that cause the disorder rye grass staggers in livestock grazing on pastures infected with certain fungi. Paxilline itself produces similar symptoms and the 14 C-labelled compound has been produced bio-synthetically at low specific activity. Using conventional liquid scintillation counting it was not possible to detect the labelled compound in the brain of mice sacrificed at the time they displayed physiological symptoms. Accelerator mass spectrometry (AMS) counts 14 C atoms, not decays, and provides sensitivity 10,000-100,000 times greater than conventional scintillation counting of radioactive decays. Measurements are easily obtained at the level of the natural abundance of 14 C in living tissue of 6fCi or 10 -16 moles 14 C per mg total carbon. Extraction of the labelled compound from the tissue is unnecessary and sample size can be 0.01-10mg. Paxilline (8mg/kg ip) was given to 25g mice. The total activity injected was 11,000 dpm though the results showed that 1,000dpm would have been sufficient. The concentration of paxilline in homogenised whole brain was determined to be 985 pg or 0.0075 dpm mg dry tissue. The concentration in the major brain segments ranged from 893-1137 pgmg dry tissue. The spinal cord contained 719 pg/mg dry tissue. Our results suggest that toxicologists and pharmacologists should consider what new information may be obtained by combining tracer studies with the power of AMS detection. The AMS method makes possible great reductions in the amount of label and sample sizes, plus wider ranges in concentration/time course studies. In particular, it opens up new possibilities such as: studies at true dietary or environmental levels; tracer studies in large animal or plant systems; field trials; human studies where radiation dose must be considered; and studies with compounds that can only be synthesised with low specific activity. Copyright (1999) Australasian

  4. Intracavity optogalvanic spectroscopy. An analytical technique for 14C analysis with subattomole sensitivity.

    Science.gov (United States)

    Murnick, Daniel E; Dogru, Ozgur; Ilkmen, Erhan

    2008-07-01

    We show a new ultrasensitive laser-based analytical technique, intracavity optogalvanic spectroscopy, allowing extremely high sensitivity for detection of (14)C-labeled carbon dioxide. Capable of replacing large accelerator mass spectrometers, the technique quantifies attomoles of (14)C in submicrogram samples. Based on the specificity of narrow laser resonances coupled with the sensitivity provided by standing waves in an optical cavity and detection via impedance variations, limits of detection near 10(-15) (14)C/(12)C ratios are obtained. Using a 15-W (14)CO2 laser, a linear calibration with samples from 10(-15) to >1.5 x 10(-12) in (14)C/(12)C ratios, as determined by accelerator mass spectrometry, is demonstrated. Possible applications include microdosing studies in drug development, individualized subtherapeutic tests of drug metabolism, carbon dating and real time monitoring of atmospheric radiocarbon. The method can also be applied to detection of other trace entities.

  5. Radioactivity measurements for determining bacterial increase and sensitivity to antibiotics. [/sup 14/C tracer

    Energy Technology Data Exchange (ETDEWEB)

    Jaszsagi-Nagy, E [Magyar Tudomanyos Akademia, Budapest; Lendvay, J [Orszagos Frederic Joliot-Curie Sugarbiologiai es Sugaregeszsegugyi Kutato Intezet, Budapest (Hungary)

    1976-01-01

    The authors elaborated a sensitive and objective measuring method for determining the bacteria increase in biological material and the sensitivity to antibiotics. When /sup 14/C glucose is added to the medium as the single source of sugar, the respiratory carbon dioxide formed by the bacteria reflects the rate of increase. The released /sup 14/C dioxide can be measured continuously without loss to the environment and the degree of bacterial infection and the antibiotic activity, respectively, can be determined.

  6. Synthesis of glycolic acid-1-14C of high specific activity

    International Nuclear Information System (INIS)

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

    1987-01-01

    A simple procedure is described which efficiently converts traces of 14 C labelled cyanide present as a dilute solution into glycolic acid-1- 14 C with more than 85% radiochemical recovery and of high specific activity. (author)

  7. Synthesis of [diene-"1"4C] curcumin at high specific activity

    International Nuclear Information System (INIS)

    Filer, Crist N.; Lacy, James M.; Wright, Christopher

    2016-01-01

    An efficient method is described to label curcumin with "1"4C at high specific activity. - Highlights: • This paper describes the synthesis of ["1"4C] Curcumin at the highest specific activity and total activity amount yet reported. • The "1"4C label was installed in the diene framework of Curcumin. • This paper also describes the characterization of ["1"4C] Curcumin by HPLC and mass spectrometry.

  8. A high resolution method for {sup 14}C analysis of a coral from South China Sea: Implication for “AD 775” {sup 14}C event

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Ping [State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou (China); Shen, Chengde, E-mail: cdshen@gig.ac.cn [State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou (China); State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 Beijing (China); Yi, Weixi; Wang, Ning [State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou (China); Ding, Xingfang; Liu, Kexin; Fu, Dongpo [State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 Beijing (China); Liu, Weiguo [State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, 710075 Xi’an (China); Liu, Yi [CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, 230026 Hefei (China)

    2015-10-15

    A pre-heating method that improves the background and precision of {sup 14}C dating significantly was applied for fossil coral dating with high resolution in our lab in Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (GIGCAS). The reaction tube is heated under 300 °C in a vacuum line before it is used for graphitization. The method can reduce the contamination absorbed in TiH{sub 2}, Zn and Fe power placed in the graphitization tube. With the pre-heating and average drilling method, bi-weekly resolution {sup 14}C dating in a fossil coral is carried out to investigate the “AD 775 {sup 14}C spike event”. Different from the tree ring {sup 14}C archives with the {sup 14}C spike of ∼15‰ (Δ{sup 14}C), the {sup 14}C spike in the coral shows an abrupt peak of 45‰ and two smaller spikes of Δ{sup 14}C > 20‰ in half a year in AD 776. And then, the {sup 14}C content in coral decreases gradually in AD 777. The peak time of the {sup 14}C spike event likely occurs in the summer of AD 776 according to the δ{sup 18}O variation in coral. High-resolution dating of {sup 14}C in coral provides not only a more detail process of the event than that from tree rings, but also the first report of the event from sea ecosystem. Both of them suggest an extraterrestrial origin of the event cause.

  9. 14C autoradiography with an energy-sensitive silicon pixel detector.

    Science.gov (United States)

    Esposito, M; Mettivier, G; Russo, P

    2011-04-07

    The first performance tests are presented of a carbon-14 ((14)C) beta-particle digital autoradiography system with an energy-sensitive hybrid silicon pixel detector based on the Timepix readout circuit. Timepix was developed by the Medipix2 Collaboration and it is similar to the photon-counting Medipix2 circuit, except for an added time-based synchronization logic which allows derivation of energy information from the time-over-threshold signal. This feature permits direct energy measurements in each pixel of the detector array. Timepix is bump-bonded to a 300 µm thick silicon detector with 256 × 256 pixels of 55 µm pitch. Since an energetic beta-particle could release its kinetic energy in more than one detector pixel as it slows down in the semiconductor detector, an off-line image analysis procedure was adopted in which the single-particle cluster of hit pixels is recognized; its total energy is calculated and the position of interaction on the detector surface is attributed to the centre of the charge cluster. Measurements reported are detector sensitivity, (4.11 ± 0.03) × 10(-3) cps mm(-2) kBq(-1) g, background level, (3.59 ± 0.01) × 10(-5) cps mm(-2), and minimum detectable activity, 0.0077 Bq. The spatial resolution is 76.9 µm full-width at half-maximum. These figures are compared with several digital imaging detectors for (14)C beta-particle digital autoradiography.

  10. High resolution 14C dating of surface peat using the AMS technique

    International Nuclear Information System (INIS)

    Tolonen, K.; Possnert, G.; Jungner, H.; Sonninen, E.; Alm, J.

    1992-01-01

    In an AMS (Accelerator Mass Spectrometric) determination of 14 C from moss-increment dated samples from a Sphagnum fuscum hummock, a clear peak representing the time of high 14 C activity in the atmosphere due to nuclear bomb tests was found. The C-14 activities in the peat profile at deeper levels, corresponding to the period down to 1600 Bp, showed similar variations as the atmospheric values. The time scale obtained from radiocarbon dating fitted well with results from moss-increment counting, pollen analysis and dendrochronological dating of a fire horizon. Using the bomb layers and refixing into growing peat was estimated. The fraction of soil carbon dioxide taken up by the contemporary Sphagnum Sward was thus found to be in the order of 20 %. (orig.). (15 refs., 5 figs., 2 tabs.)

  11. Characteristics of high-purity Teflon vial for 14C measurement in old tree rings

    International Nuclear Information System (INIS)

    Sakurai, H.; Saswaki, Y.; Matsumoto, T.; Aoki, T.; Kato, W.; Gandou, T.; Gunji, S.; Tokanai, F.

    2003-01-01

    14 C concentration in single-year tree rings of an old cedar of ca. 2500 years ago is measured to investigate the 11-yr periodicity of solar activity. Our highly accurate 14 C measuring system is composed of a benzene synthesizer capable of producing a large quantity (10 g) of benzene and a Quantulus 1220 TM liquid scintillation counting system. The accuracy is less than 0.2% for measurements of 14 C concentration. The benzene sample is contained in a high-purity Teflon/copper-counting vial (20 ml) manufactured by Wallac Oy Company. We found a vial with an irregular copper cap for the measurements of 11 tree rings. The behavior of the vial with the irregular cap was investigated. The Teflon sheet inside the cap plays an important role in achieving stable measurement. The rate of volatilization of the benzene was less than 0.35 mg/day for vials with ordinary caps. This results in the volatilization rate of 0.003% for 10.5 g of benzene and hence guarantees measurement at an accuracy of 0.2% for 70 days

  12. Correlating the Ancient Maya and Modern European Calendars with High-Precision AMS 14C Dating

    Science.gov (United States)

    Kennett, Douglas J.; Hajdas, Irka; Culleton, Brendan J.; Belmecheri, Soumaya; Martin, Simon; Neff, Hector; Awe, Jaime; Graham, Heather V.; Freeman, Katherine H.; Newsom, Lee; Lentz, David L.; Anselmetti, Flavio S.; Robinson, Mark; Marwan, Norbert; Southon, John; Hodell, David A.; Haug, Gerald H.

    2013-04-01

    The reasons for the development and collapse of Maya civilization remain controversial and historical events carved on stone monuments throughout this region provide a remarkable source of data about the rise and fall of these complex polities. Use of these records depends on correlating the Maya and European calendars so that they can be compared with climate and environmental datasets. Correlation constants can vary up to 1000 years and remain controversial. We report a series of high-resolution AMS 14C dates on a wooden lintel collected from the Classic Period city of Tikal bearing Maya calendar dates. The radiocarbon dates were calibrated using a Bayesian statistical model and indicate that the dates were carved on the lintel between AD 658-696. This strongly supports the Goodman-Martínez-Thompson (GMT) correlation and the hypothesis that climate change played an important role in the development and demise of this complex civilization.

  13. Detection of 14C-Carmoisine metabolites by high performance liquid chromatography

    International Nuclear Information System (INIS)

    Marinovich, M.; Ferrari, A.; Pacini, N.; Galli, C.L.

    1983-01-01

    14 C-Carmoisine, a sulphonated azodye, 200 mg/kg b.w. (25 μCi), was administered to rats by gavage. Separation of radioactive compounds in faeces and urine of these animals was carried out by HPLC with a UV and a radioactivity detector. In addition to unmodified carmoisine, five radioactive compounds were present. The main peak showed both the retention time and the UV spectrum of naphtionic acid. Metabolic patterns similar to those observed ''in vivo'' were found by incubation of 14 C-carmoisine under anaerobic conditions with a bacterial suspension isolated from human faeces and from the intestinal contents of rats. This procedure permits the preparation of amounts of unknown metabolites suitable for their identification. (orig.)

  14. L-tryptophan synthesis from 14C-anthranilic acid in plants with high and low tryptophan content

    International Nuclear Information System (INIS)

    Kutacek, M.; Eder, J.; Vackova, K.; Prochazka, S.

    1978-01-01

    The biosynthesis of L-tryptophan (L-trp) from anthranilic acid- 14 C (AA- 14 C) in undamaged organs of the seedlings of kohlrabi and peas, with high L-trp content and maize plants, with low L-trp content was compared. As for maize the experiments were carried out with normal and opaque-2 phenotypes, both with the seedlings and with the ripening kernels. AA- 14 C is metabolized in the plants to L-trp pool and to glycosyl esters of AA. In maize seedlings L-trp- 14 C is synthesized relatively less than in kohlrabi and in pea. The de novo formation of L-trp- 14 C is stopped earlier in maize than in kohlrabi. The level of free L-trp- 14 C is relatively low in maize in comparison with kohlrabi and peas. In spite of this the formation of L-trp- 14 C from AA- 14 C is sufficient in maize to incorporate L-trp both into the proteins and into a secondary metabolite that is not yet defined. At the period of seedlings the incorporation in maize of L-trp into the proteins is comparable with that in kohlrabi, and it is maximum in pea. Maize, at the stage of germination, thus forms proteins rich in L-trp. The formation of free L-trp is approximately ten times lower in ripening kernels and in the leaves adjacent to the ear and it further decreases in the course of the ripening of the kernels. Although the activity of the biosynthesis of the AA- 14 C→L-trp- 14 C pathway is relatively lower in maize than in kohlrabi and peas, this pathway is most responsible for the differences in the content of L-trp in these plants. Neither amitrol nor histidine affected the biosynthesis of L-trp in kohlrabi; the interaction of the biosynthetic pathways of L-trp and histidine known in microorganisms is thus not important in a higher plant. (author)

  15. 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

  16. Multipolarity analysis for 14C high-energy resonance populated by (18O,16O) two-neutron transfer reaction

    International Nuclear Information System (INIS)

    Carbone, D.; Cavallaro, M.; Bondì, M.; Agodi, C.; Cunsolo, A.; Cappuzzello, F.; Azaiez, F.; Franchoo, S.; Khan, E.; Bonaccorso, A.; Fortunato, L.; Foti, A.; Linares, R.; Lubian, J.; Scarpaci, J. A.; Vitturi, A.

    2015-01-01

    The 12 C( 18 O, 16 O) 14 C reaction at 84 MeV incident energy has been explored up to high excitation energy of the residual nucleus thanks to the use of the MAGNEX spectrometer to detect the ejectiles. In the region above the two-neutron separation energy, a resonance has been observed at 16.9 MeV. A multipolarity analysis of the cross section angular distribution indicates an L = 0 character for such a transition

  17. Surface water processes in the Indonesian throughflow as documented by a high-resolution coral Δ14C record

    Science.gov (United States)

    Fallon, Stewart J.; Guilderson, Thomas P.

    2008-09-01

    To explore the seasonal to decadal variability in surface water masses that contribute to the Indonesian throughflow, we have generated a 115-year bimonthly coral-based radiocarbon time series from a coral in the Makassar Straits. In the pre-bomb (pre-1955) era from 1890 to 1954, the radiocarbon time series occasionally displays a small seasonal signal (10-15‰). After 1954 the radiocarbon record increases rapidly, in response to the increased atmospheric 14C content caused by nuclear weapons testing. From 1957 to 1986 the record displays clear seasonal variability from 15 to 60‰ and the post-bomb peak (163 per mil) occurred in 1974. The seasonal cycle of radiocarbon can be attributed to variations of surface waters passing through the South Makassar Strait. Southern Makassar is under the influence of the Northwest Monsoon, which is responsible for the high austral summer radiocarbon (North Pacific waters) and the Southeast Monsoon that flushes back a mixture of low (South Pacific and upwelling altered) radiocarbon water from the Banda Sea. The coral record also shows a significant 14C peak in 1955 due to the bomb-14C water advected into this region from nuclear weapons tests in the Marshall Islands in 1954.

  18. Preliminary description of a dedicated commercial ultra-sensitive mass spectrometer for direct atom counting of 14C

    International Nuclear Information System (INIS)

    Purser, K.H.; Schneider, R.J.; Post, R.; Dobbs, J.McG.

    1981-01-01

    A description is presented of a commercial, tandem-accelerator centered secondary ion double mass spectrometer dedicated to 14 C/ 13 C/ 12 C ratio measurements. Some design philosophy of the instrument is presented and the performance is described. A scanning cesium ion source with primary beam diameters between 100 to 200 micrometers is used to produce C - beam intensities of 10 to 20μA with the intensities remaining constant to better than 0.1% per minute after the source stabilizes. For recent carbon, these currents correspond to 14 C count rates from the ion source of 60 to 120 particles per second. Resolution of the first mass defining system, M/ΔM, is greater than 120 with the capability of rapid mass switching between isotopes. The measured isotopic ratios at the ion source for carbon are constant to better than 0.25%. The virtues of the 3MV parallel-fed Cockroft-Walton accelerator supply are presented. At the operating voltage of 2.5MV, the stability is better than 1:4000 with a terminal ripple 13 C 3+ and 12 C 3+ ions which originate from mass-14 molecular ions are measured to be 3.6mm away from the beam axis and so can be completely eliminated by the slits. Isotopic ratios have been measured beyond these slits, and it is shown that these ratios are constant to better than half a percent using recent samples. The final strong focusing magnet has a rejection ratio for unwanted carbon ions greater than 10 7

  19. Method of preparing uridine-diphospho-/sup 14/C-D-glucose of high molar activity and radiochemical purity by enzyme synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, V; Biely, P; Koelbl, J

    1980-06-15

    A new method is described of enzyme synthesis of uridine-diphospho-/sup 14/C-D-glucose of high molar activity. After conversion of the initial /sup 14/C-D-glucose, the accompanying sugar phosphates and nucleoside-5'-phosphates are selectively hydrolyzed by the action of alkaline phosphatase in the presence of phenolphthalein as an indicator. Uridine-diphospho-/sup 14/C-D-glucose is separated by paper chromatography from the reaction mixture thus modified. Synthesis yields range within 75% and 85% relative to the starting /sup 14/C-D-glucose.

  20. The development of high precision 14C measurement and its application to archaeological time-scale problems

    International Nuclear Information System (INIS)

    Pearson, G.W.

    1983-01-01

    High precision calibration curve of some 6000 years has been constructed from the measurement of contiguous 20 year samples of dendrochronologically dated Irish oak. 14 C evidence was presented using a 'wiggle' matching technique which supported the dendrochronological fixing of the BC period Irish oak chronology. Two archaeological samples were 'wiggle matched' to give a calendar age within a range of 25 years and proved that this technique is as precise as dendrochronological dating and is potentially as useful for a much wider range of samples and growth periods. (author)

  1. Simple syntheses of 3-substituted indoles and their application for high yield 14C-labelling

    International Nuclear Information System (INIS)

    Schallenberg, J.; Meyer, E.

    1983-01-01

    Methods are described which allow the synthesis of several plant indole alkaloids and their metabolites at different scales. Compounds synthesized include gramine (1) (3-dimethylaminomethylindole) which is directly derived from indole, while its biosynthetic precursors 3-aminomethylindole (3) and 3-methylaminomethylindole (2) as well as indole3-carboxylic acid (7) are synthesized via indole-3-aldehyde (6). Slight changes of the experimental conditions allow syntheses with high yields not only at the molar but also at the μmolar level. This is extremely useful when isotope labelled compounds of high specific radioactivity are required for studies of plant metabolism. (orig.)

  2. Utilization of [1-14C]carbon of glycine of high glycine diet fed young and old rats

    International Nuclear Information System (INIS)

    Petzke, K.J.; Albrecht, V.; Medovar, B.Ya.; Pisarczuk, K.L.; Grigorov, Yu.G.

    1987-01-01

    The incorporation of radioactivity from [1- 14 C]glycine was studied in various organ (serum, liver, muscle) fractions (acid soluble, proteins, lipids, liver glycogen) and carbon dioxide in rats fed with isonitrogenous isocaloric purfied diets. The diets contained 30% casein (control), gelatin (exchange of half of the 30% casein) or glycine (corresponding level of glycine in relation to the gelatin diet). The incorporation of radioactivity into proteins was reduced by feeding high glycine diets in young (20-weeks-old) and old (18-month-old) rats in relation to the control diet. The modifications of the results for old animals may be partially explained on the base of a reduced protein turnover rate and adaptation to a high gelatin (glycine) diet. (author)

  3. Sensitive method for continuous air monitoring for /sup 14/C and /sup 3/H. Empfindliches verfahren zur koninuierlichen C-14 und H-3 luftueberwachung

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, J.; Weiss, W.

    1976-07-01

    In the monitoring of air for /sup 14/C and /sup 3/H the necessary sensitivity cannot be achieved by direct measurement, but only through continuous sampling and scintillation spectroscopy. The two radionuclides are separated from each other at the time of sampling. In addition, by a catalytic reaction over CuO at 600/sup 0/C, a differentiation is achieved between tritiated atmospheric water vapor (HTO), /sup 14/CO/sub 2/ and other isotopically labeled substances contained in the air. Tritium is obtained in the form of water and /sup 14/C as Na/sub 2//sup 14/CO/sub 3/. Radioactivity is measured in a scintillation spectrometer. For tritium this method has a detection limit of 0.8 pCi/m/sup 3/ or air, and for C/sup 14/ 0.6 pCi/m/sup 3/ of air. These values correspond to 15 to 30% of the mean background concentration for HTO and /sup 14/CO/sub 2/ observed up to the present.

  4. A convenient synthesis of sup 14 C-cotinine from sup 14 C-nicotine

    Energy Technology Data Exchange (ETDEWEB)

    Desai, D.H.; Djordjevic, M.V.; Amin, S. (American Health Foundation, Valhalla, NY (USA). Naylor Dana Inst. for Disease Prevention)

    1991-03-01

    A convenient synthesis with analytical monitoring of {sup 14}C-cotinine is reported. {sup 14}C-Nicotine was converted into {sup 14}C-dibromocotinine hydrobromide perbromide. Debromination, achieved by using Zn dust/acetic acid, resulted in high yields (71%) of {sup 14}C-cotinine. (author).

  5. The effect of label affinity on the sensitivity and specificity of a hapten radioimmunoassay: A comparison of three [125I]diphenylhydantoin radioligands with the 14C-labelled drug

    International Nuclear Information System (INIS)

    Rowell, F.J.

    1979-01-01

    The effects on the sensitivity and specificity of a radioimmunoassay for diphenylhydantoin (DPH) has been investigated using three 125 I-labelled tyrosine ester derivatives of DPH having different bridge lengths between the tyrosine moiety and the DPH moeity and 14 C-labelled DPH. The results demonstrate that for a hapten which does not completely fill the antibody binding sites, greatest sensitivity is achieved when the bridge of the iodine label is most dissimilar to that present in the original immunogen, when the hapten and label affinities are nearly equivalent. Greatest specificity is achieved with the label which most resembles the original immunogen. These results illustrate the difficulty of designing satisfactory labels for assays of both high specificity and sensitivity since minimal changes in label structure may produce greatly amplified changes in the subsequent affinity of the label for the antiserum. (Auth.)

  6. 14C analysis via intracavity optogalvanic spectroscopy

    International Nuclear Information System (INIS)

    Murnick, Daniel; Dogru, Ozgur; Ilkmen, Erhan

    2010-01-01

    A new ultra sensitive laser-based analytical technique, intracavity optogalvanic spectroscopy (ICOGS), allowing extremely high sensitivity for detection of 14 C-labeled carbon dioxide has recently been demonstrated. Capable of replacing accelerator mass spectrometers (AMS) for many applications, the technique quantifies zeptomoles of 14 C in sub micromole CO 2 samples. Based on the specificity of narrow laser resonances coupled with the sensitivity provided by standing waves in an optical cavity, and detection via impedance variations, limits of detection near 10 -1514 C/ 12 C ratios have been obtained with theoretical limits much lower. Using a 15 W 14 CO 2 laser, a linear calibration with samples from 5 x 10 -15 to >1.5 x 10 -12 in 14 C/ 12 C ratios, as determined by AMS, was demonstrated. Calibration becomes non-linear over larger concentration ranges due to interactions between CO 2 and buffer gas, laser saturation effects and changes in equilibration time constants. The instrument is small (table top), low maintenance and can be coupled to GC or LC input. The method can also be applied to detection of other trace entities. Possible applications include microdosing studies in drug development, individualized sub-therapeutic tests of drug metabolism, carbon dating and real time monitoring of atmospheric radiocarbon.

  7. Metabolism of high density lipoproteins reconstituted with [3H]cholesteryl ester and [14C]cholesterol in the rat, with special reference to the ovary

    International Nuclear Information System (INIS)

    Nestler, J.E.; Bamberger, M.; Rothblat, G.H.; Strauss, J.F. III

    1985-01-01

    In order to study the metabolism of high density lipoprotein (HDL)-carried sterol in the rat, human HDL was reconstituted with [ 14 C]cholesterol and [ 3 H]cholesteryl ester. After iv injection into immature PMSG-human CG primed rats pretreated with 4-aminopyrazolopyrimidine and aminoglutethimide, there was time-dependent accumulation of 3 H and 14 C in various organs which reached a maximum by 15-90 min. On a milligram wet weight basis, uptake of 3 H and 14 C was greatest in the adrenals, next in ovaries, followed by the liver, with little uptake by kidneys and spleen. On an organ basis, accumulation was greatest by the liver. Coadministration of excess unlabeled HDL, but not human low density lipoprotein, reduced accumulation of radioactivity by the ovaries and adrenals by 60%, indicating a specific and saturable uptake process. Granulosa cells cultured in lipoprotein-deficient medium with reconstituted HDL formed 3 H- and 14 C-labeled 20 alpha-hydroxypregn-4-en-3-one. Over a 24-h period, utilization of both [ 14 C]cholesterol and [ 3 H]cholesteryl ester was linear, but rates of utilization of the two sterol moieties were not parallel. Lysosomotropic agents had no effect on utilization of either free or esterified cholesterol for steroidogenesis but reduced degradation of 125 I-labeled low density lipoprotein apoprotein. These findings lend further support to the concept of a distinct HDL pathway in steroidogenic cells of the rat

  8. Effects of source and sink manipulation on distribution of 14C-assimilate and endogenous hormone contents of high-yield cotton in Xinjiang

    International Nuclear Information System (INIS)

    Luo Honghai; Zhao Ruihai; Li Junhua; Zhang Yali; Zhang Wangfeng

    2011-01-01

    Effects of leaf-cutting and bud-thinning treatment on partitioning of 14 C-assimilate and endogenous hormone contents of source leaf (respective axial leaf and sympodian leaf) during flowering and boll-setting stage in high-yield cotton were studied by using Gossipium hirsutum L. cv. Xinluzao 132 as plant material. Results showed that bud-thinning reduced the peak value of indole-3-acetic acid (IAA) delayed the accumulation of isopenteny ladenime and its riboside (iP + iPA), and decreased the contents of abscisic acid (ABA) zeatin and its riboside (Z + ZR) of source leaf. Thus, the export and partitioning of percentage of 14 C-assimilate in boll was significantly decreased at full bolling and boll opening stages. As a result, both of boll weight and yield in bud-thinning were significantly lower than control. Leaf-cutting significantly improved the content of cytokinins (CTKs) and the distributive percentage of 14 C-assimilates in boll. Furthermore, when leaves were cut 1/4 at anthesis, no differences were found in number of bolls per plant, boll weight and yield compared with control. These results suggested that regulating source-sink relation with key practices of cultivation would be of great importance to super-high and stable yield of cotton, as it would affect the changes of endogenous hormone levels and regulate the distribution of 14 C-assimilate between source and sink. (authors)

  9. A 3500 14C yr High-Resolution Record of Water-Level Changes in Lake Titicaca, Bolivia/Peru

    Science.gov (United States)

    Abbott, Mark B.; Binford, Michael W.; Brenner, Mark; Kelts, Kerry R.

    1997-03-01

    Sediment cores collected from the southern basin of Lake Titicaca (Bolivia/Peru) on a transect from 4.6 m above overflow level to 15.1 m below overflow level are used to identify a new century-scale chronology of Holocene lake-level variations. The results indicate that lithologic and geochemical analyses on a transect of cores can be used to identify and date century-scale lake-level changes. Detailed sedimentary analyses of subfacies and radiocarbon dating were conducted on four representative cores. A chronology based on 60 accelerator mass spectrometer radiocarbon measurements constrains the timing of water-level fluctuations. Two methods were used to estimate the 14C reservoir age. Both indicate that it has remained nearly constant at ˜250 14C yr during the late Holocene. Core studies based on lithology and geochemistry establish the timing and magnitude of five periods of low lake level, implying negative moisture balance for the northern Andean altiplano over the last 3500 cal yr. Between 3500 and 3350 cal yr B.P., a transition from massive, inorganic-clay facies to laminated organic-matter-rich silts in each of the four cores signals a water-level rise after a prolonged mid-Holocene dry phase. Evidence of other significant low lake levels occurs 2900-2800, 2400-2200, 2000-1700, and 900-500 cal yr B.P. Several of the low lake levels coincided with cultural changes in the region, including the collapse of the Tiwanaku civilization.

  10. Multipolarity analysis for {sup 14}C high-energy resonance populated by ({sup 18}O,{sup 16}O) two-neutron transfer reaction

    Energy Technology Data Exchange (ETDEWEB)

    Carbone, D., E-mail: carboned@lns.infn.it; Cavallaro, M.; Bondì, M.; Agodi, C.; Cunsolo, A. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Cappuzzello, F. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Azaiez, F.; Franchoo, S.; Khan, E. [Institut de Physique Nucleaire, Universitè Paris-Sud, Orsay (France); Bonaccorso, A. [INFN-Sezione di Pisa, Pisa (Italy); Fortunato, L. [Dipartimento di Fisica e Astronomia, Università di Padova, Padova (Italy); INFN-Sezione di Padova, Padova (Italy); Foti, A. [Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); INFN-Sezione di Catania, Catania (Italy); Linares, R.; Lubian, J. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi (Brazil); Scarpaci, J. A. [Centre de Sciences Nucleaires et de Sciences de Matieres, Universitè Paris-Sud, Orsay (France); Vitturi, A. [INFN-Sezione di Padova, Padova (Italy); INFN-Sezione di Catania, Catania (Italy)

    2015-10-15

    The {sup 12}C({sup 18}O,{sup 16}O){sup 14}C reaction at 84 MeV incident energy has been explored up to high excitation energy of the residual nucleus thanks to the use of the MAGNEX spectrometer to detect the ejectiles. In the region above the two-neutron separation energy, a resonance has been observed at 16.9 MeV. A multipolarity analysis of the cross section angular distribution indicates an L = 0 character for such a transition.

  11. 14C Records from Indonesian Sea

    International Nuclear Information System (INIS)

    Baresic, J.; Fallon, S.; Mazerat, J.

    2013-01-01

    To investigate ocean currents and past climate events affecting the Indonesian throughflow (ITF), a radiocarbon record from a Porites coral collected from Alor Island, Indonesia, was constructed. Porites corals are often used in paleoclimate research and water mass circulation studies in the Tropics because of their abundance in the region and growth rate of 8 - 20 mm/y. These characteristics allow reconstructions of past environmental changes on weekly to annual time scales. At this point radiocarbon coral results from Alor cover approximately 30 years. An age model was constructed using the sea surface temperature proxy δ18O. Alor radiocarbon results were compared with previous measurements obtained from Padang and Langkai corals. a14C values obtained from the Alor coral display a strong seasonal cycle, high values during Australian summer and low values during Australian winter. Higher a 14C summer values indicate inflow of waters enriched by 14C through Makassar Strait from the North Pacific Ocean and Java Sea surface water. Summer a14C values are also enhanced by summer stratification. Winter values indicate upwelling of deep Ocean waters within the research area and transport of 14C-depleted waters from the Banda Sea, which has input from the South Pacific Ocean (lower a14C than North Pacific). Therefore, the a14C coral record reflects the movement of enriched water from North Pacific to Indian Ocean through Makassar Strait during summer and upwelling of depleted surface waters from the Banda Sea during the winter. Lower a14C dips could be attributed to strong El Nino events, which would enhance surface water mixing and upwelling of low radiocarbon deep waters. Water transport from North Pacific Ocean decreases during El Nino events also contributing to lowering of a14C signal.(author)

  12. Demonstration of tyrosinase in the vitiligo skin of human beings by a sensitive fluorometric method as well as by 14C(U)-L-tyrosine incorporation into melanin

    International Nuclear Information System (INIS)

    Husain, I.; Vijayan, E.; Ramaiah, A.; Pasricha, J.S.; Madan, N.C.

    1982-01-01

    Tyrosinase activity (Monophenol, dihydroxyphenylalanine: oxygen oxidoreductase EC 1.14.18.1) in vitiligo and normal epidermal homogenates of skin from human beings was measured by estimating beta 3,4-dihydroxyphenylalanine (dopa) by a highly sensitive fluorometric method described in this paper. The tyrosine activity in the vitiligo skin was about 4 to 37% of corresponding normal skin. The activity of tyrosinase in normal human skin from different individuals and from different regions of the body was in the range of 4 to 140 picomoles of beta 3,4-dihydroxyphenylalanine formed per min/mg protein of epidermal homogenate. The enzyme from vitiligo and normal skin was severely inhibited by substance(s) of low molecular weight. The enzyme exhibits a lag of about 4 hr in the absence of added beta 3,4-dihydroxyphenylalanine and 1 hr in presence of 5 microM dopa. Tyrosinase from the normal and vitiligo skin was inhibited by excess concentration of tyrosine. The homogenates from vitiligo skin could synthesize melanin from C14(U)-L-Tyrosine. The rate of tyrosine incorporation into melanin by the epidermal homogenates is increased by 3,4-dihydroxyphenylalanine (dopa) disproportionate to its effect on tyrosinase activity. Based on the data presented in this paper it is concluded that melanocytes are present in the vitiligo skin. A tentative hypothesis is put forward to explain the lack of melanin synthesis by the vitiligo skin under in vivo conditions, although melanocytes are present

  13. Bioconversion of α-[14C]Zearalenol and β-[14C]Zearalenol into [14C]Zearalenone by Fusarium roseum Gibbosum

    International Nuclear Information System (INIS)

    Richardson, K.E.; Hagler, W.M. Jr.; Hamilton, P.B.

    1984-01-01

    Cultures of Fusarium roseum Gibbosum on rice were treated with [ 14 C]zearalenone, α-[ 14 C]zearalenol, or β-[ 14 C]zearalenol to determine whether a precursor-product relationship exists among these closely related fungal metabolites. Culture extracts were purified by silica gel column chromatography and fractionated by high-pressure liquid chromatography, and the level of radioactivity was determined. Within 7 days, the β-[ 14 C]zearalenol was converted to zearalenone, and no residual β-[ 14 C]zearalenol was detectable. Most of the α-[ 14 C]zearalenol added was also converted into zearalenone within 14 days. In cultures treated with [ 14 C]zearalenone, no radioactivity was noted in any other components

  14. Sensitivity to House Dust Mites Allergens with Atopic Asthma and Its Relationship with CD14 C(-159T) Polymorphism in Patients of West Bengal, India.

    Science.gov (United States)

    Ghosh, Amlan; Dutta, Shampa; Podder, Sanjoy; Mondal, Priti; Laha, Arghya; Saha, Nimai Chandra; Moitra, Saibal; Saha, Goutam Kumar

    2018-01-10

    India is the home to around 15-20 million asthmatics, and asthma prevalence is increasing in Indian metropolitan area, including Kolkata, West Bengal. Complex interactions of genetic and environmental factors are involved in asthma. Genome-wide search for susceptible loci regulating IgE response (atopy) have identified a candidate gene CD14 which is most important in the context of allergic responses of respiratory system. This study was aimed to investigate the role of house dust and house dust mites in development of bronchial asthma and to explore the possible association of candidate gene CD14 with disease manifestation among Kolkata patient population. Skin-prick test was done among 950 asthmatic patients against 8 aeroallergens, including house dust and house dust mites and total serum IgE and allergen-specific IgE were measured. Polymerase chain reaction-restriction fragment length polymorphism was done in patients and nonasthmatic control (n = 255 in each) to characterize a functional polymorphism, C(-159)T, of CD14, a positional candidate gene for allergy. We identified house dust as the most common aeroallergen sensitizer among atopic patients in Kolkata followed by Dermatophagoides pteronyssinus and Dermatophagoides farinae Hughes (Acari: Pyroglyphidae) mites. Patient's sera contain significantly higher IgE level than that of control. Allergen-specific IgE antibody test revealed that 76.36% patients had specific IgE antibody against D. pteronyssinus mite. There was a significant difference in the distribution of alleles and genotypes for CD14 polymorphism with an increase in disease severity. So, in Kolkata, house dust mite is a common aeroallergen and D. pteronyssinus is predominant among mites. The present study revealed that bronchial asthma has a genetic background. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Metabolism and distribution of two 14C-benzidine-congener-based dyes in rats as determined by gas chromatography, high-pressure liquid chromatography, and radioassays. Final report Jan-Oct 81

    International Nuclear Information System (INIS)

    Oller, W.L.

    1983-04-01

    Absorption, metabolism, and tissue distribution studies were conducted in the rat with 14 C-biphenyl ring-labeled Direct Blue 15, a 3,3'-dimethoxybenzidine (DiMxBzd) based azo dye; Direct Red 2, based on 3,3'-dimethylbenzidine (DiMeBzd) and the corresponding benzidine congener amines. Single oral doses of the 14 C-labeled dyes (12 mg/kg, 62 micro Ci/kg) and molar equivalent doses of the respective amines were administered and urine and fecal samples collected at intervals up to 192 hours. Urine and fecal samples were analyzed for 14 C content. Most of the 14 C present in the urine could not be extracted with benzene nor chloroform, indicating high polarity. Distribution studies conducted with both dyes showed that liver, kidney, and lung accumulated and retained higher levels of 14 C than other tissues (at 72 hrs). Peak levels of 14 C, which occurred 8-12 hours after dosing, were significantly higher with Direct Red 2 than Direct Blue 15. Tissue distribution data (72 hr) for rats dosed with the free amines compared with the dyes showed a generally lower but similar distribution pattern

  16. 14C Behaviour in PWR coolant

    International Nuclear Information System (INIS)

    Sims, Howard; Dickinson Shirley; Garbett, Keith

    2012-09-01

    Although 14 C is produced in relatively small amounts in PWR coolant, it is important to know its fate, for example whether it is released by gaseous discharge, removed by absorption on ion exchange (IX) resins or deposited on the fuel pin surfaces. 14 C can exist in a range of possible chemical forms: inorganic carbon compounds (probably mainly CO 2 ), elemental carbon, and organic compounds such as hydrocarbons. This paper presents results from a preliminary survey of the possible reactions of 14 C in PWR coolant. The main conclusions of the study are: - A combination of thermal and radiolytic reactions controls the chemistry of 14 C in reactor coolant. A simple chemical kinetic model predicts that CH 3 OH would be the initial product from radiolytic reactions of 14 C following its formation from 17 O. CH 3 OH is predicted to arise as a result of reactions of OH . with CH 4 and CH 3 , and it persists because there is no known radiation chemical reduction mechanism. - Thermodynamic considerations show that CH 3 OH can be thermally reduced to CH 4 in PWR conditions, although formation of CO 2 from small organics is the most thermodynamically favourable outcome. Such reactions could be catalysed on active nickel surfaces in the primary circuit. - Limited plant data would suggest that CH 4 is the dominant form in PWR and CO 2 in BWR. This implies that radiation chemistry may be important in determining the speciation. - Addition of acetate does not affect the amount of 14 C formed, but the addition of large amounts of stable carbon would lead to a large range of additional products, some of which would be expected to deposit on fuel pin surfaces as high molecular weight hydrocarbons. However, the subsequent thermal decomposition reactions of these products are not known. - Acetate addition may represent a small input of 12 C compared with organic material released from CVCS resins, although the importance of this may depend on whether that is predominantly soluble

  17. Reassessment of the C-13/C-12 and C-14/C-12 isotopic fractionation ratio and its impact on high-precision radiocarbon dating

    NARCIS (Netherlands)

    Fahrni, Simon M.; Southon, John R.; Santos, Guaciara M.; Palstra, Sanne W. L.; Meijer, Harro A. J.; Xu, Xiaomei

    2017-01-01

    The vast majority of radiocarbon measurement results (C-14/C-12 isotopic ratios or sample activities) are corrected for isotopic fractionation processes (measured as C-13/C-12 isotopic ratios) that occur in nature, in sample preparation and measurement. In 1954 Harmon Craig suggested a value of 2.0

  18. High-Sensitivity Spectrophotometry.

    Science.gov (United States)

    Harris, T. D.

    1982-01-01

    Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

  19. Highly Sensitive Optical Receivers

    CERN Document Server

    Schneider, Kerstin

    2006-01-01

    Highly Sensitive Optical Receivers primarily treats the circuit design of optical receivers with external photodiodes. Continuous-mode and burst-mode receivers are compared. The monograph first summarizes the basics of III/V photodetectors, transistor and noise models, bit-error rate, sensitivity and analog circuit design, thus enabling readers to understand the circuits described in the main part of the book. In order to cover the topic comprehensively, detailed descriptions of receivers for optical data communication in general and, in particular, optical burst-mode receivers in deep-sub-µm CMOS are presented. Numerous detailed and elaborate illustrations facilitate better understanding.

  20. Synthesis of 14C-dehydrocorydaline chloride

    International Nuclear Information System (INIS)

    Zhang Rui; Wang Ding

    1988-01-01

    A method for synthesis of 14 C-dehydrocorydaline chloride is described. In the presence of sodium hydroxide, acetonylpalmatine is reacted with 14 C-methyl iodide in sealed glass ampoule to give 14 C-13-methylpalmatine iodide which is then converted to chloride. The radiochemical purity of 14 C-dehydrocorydaline determined by TLC is over 98% and the labelling efficiency is 54%

  1. Behaviors of 14C-butachlor, 14C-chlorpyrifos and 14C-DDT in Rana japonica japonica Guenther

    International Nuclear Information System (INIS)

    Zhang Yiqiang; Zhong Chuangguang; Zhao Xiaokui; Chen Shunhua

    2002-01-01

    The research on the behaviors of 14 C-butachlor, 14 C-chlorpyrifos and 14 C-DDT in the frog Rana japonica japonica Guenther was carried out. After administrated per os to the frogs in doses of 380, 347, 363 Bq/g, 14 C-butachlor, 14 C-chlorpyrifos and 14 C-DDT, were distributed respectively to various organs within 24 h with specific accumulating organs as gallbladder, intestine and intestine, relevantly to the pesticides described. Compared to that in gallbladder and intestine, the radioactivity of many organs was extremely low, and this might due to the characters of the pesticides. Analysis of the metabolites of 14 C-DDT in frog at 24 th hr demonstrated that DDT was difficult to be degraded. Most 14 C-butachlor, 14 C-chlorpyrifos 14 C-DDT in liver and fat or ovary of frog was extractable with acetone. However, there were some differences between the pesticides, and the organs as well. And 14 C-butachlor, 14 C-chlorpyrifos or 14 C-DDT were better bound in liver than in fat

  2. Δ14C level of annual plants and fossil fuel derived CO2 distribution across different regions of China

    International Nuclear Information System (INIS)

    Xi, X.T.; Ding, X.F.; Fu, D.P.; Zhou, L.P.; Liu, K.X.

    2013-01-01

    The 14 C level in annual plants is a sensitive tracer for monitoring fossil fuel derived CO 2 in the atmosphere. Corn leave samples were selected from different regions of China, including high mountains in the Tibetan Plateau, grassland in Inner Mongolia, and inland and coastal cities during the summer of 2010. The 14 C/ 12 C ratio of the samples was measured with the NEC compact AMS system at the Institute of Heavy Ion Physics, Peking University. The fossil fuel derived CO 2 was estimated by comparing the measured Δ 14 C values of corn leave samples to background atmospheric Δ 14 C level. The influences of topography, meteorological conditions and carbon cycling processes on the fossil fuel derived CO 2 concentration are considered when interpreting the data. Our results show a clear association of the low Δ 14 C values with regions where human activities are intensive.

  3. 14C uncovers the past

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Radio-carbon dating, a method of dating prehistoric remains that has been developed since the Second World War, is based on the fact that all organic matter contains a radioactive isotope of carbon - 14 C- which, because it decays at a fixed rate, gives a good indication of the age of the substance. The CSIR's National Physical Research Laboratory entered the field of radio-carbon dating in 1967, when the Nature Isotopes Division was established. The division has become a world centre of excellence and much has been done to clear up the chronology of southern African prehistory. It has been found, for instance, that anatomically modern man appeared in southern Africa some 40000 years earlier than in Europe, and that the Zimbabwe ruins were built mainly around the year 1350 AD. The radio-carbon method can also be used to determine the age and flow rate of underground water and the rate at which tracer gases dissolve in the oceans, i.e. the efficiency with which the oceans cleanse the atmosphere from pollutants

  4. Bepaling van 14C in afvalwater

    NARCIS (Netherlands)

    Hiemstra YS; Kwakman PJM; Nissan LN; Aldenkamp FJ; LSO

    1998-01-01

    In opdracht van de Hoofdinspectie Milieuhygiene van het ministerie van VROM heeft LSO een methode ontwikkeld om 14C in afvalwater van nucleaire installaties te bepalen. De methode meet organisch gebonden-14C en anorganisch-14C in de vorm van carbonaat (14CO32-) in afvalwater. Het rapport

  5. 14C Accelerator mass spectrometry in Brazil

    International Nuclear Information System (INIS)

    Macario, K.D.; Gomes, P.R.S.; Anjos, Roberto M.; Linares, R.; Queiroz, E.A.; Oliveira, F.M.; Cardozo, L.; Carvalho, C.R.A.

    2011-01-01

    Radiocarbon Accelerator Mass Spectrometry is an ultra-sensitive technique that enables the direct measurement of carbon isotopes in samples as small as a few milligrams. The possibility of dating or tracing rare or even compound specific carbon samples has application in many fields of science such as Archaeology, Geosciences and Biomedicine. Several kinds of material such as wood, charcoal, carbonate and bone can be chemically treated and converted to graphite to be measured in the accelerator system. The Physics Institute of Universidade Federal Fluminense (UFF), in Brazil will soon be able to perform the complete 14 C-AMS measurement of samples. At the Nuclear Chronology Laboratory (LACRON) samples are prepared and converted to carbon dioxide. A stainless steel vacuum system was constructed for carbon dioxide purification and graphitization is performed in sealed tubes in a muffle oven. Graphite samples will be analyzed in a 250 kV Single Stage Accelerator produced by National Electrostatic Corporation which will be installed in the beginning of 2012. With the sample preparation laboratory at LACRON and the SSAMS system, the Physics Institute of UFF will be the first 14 C-AMS facility in Latin America. (author)

  6. Convenient synthesis of [2-14C]-methylglyoxal bis(guanylhydrazone), [14C]-mitoguazone

    International Nuclear Information System (INIS)

    Burgos, A.; Ellames, G.J.

    1995-01-01

    [2- 14 C]-Methylglyoxal bis(guanylhydrazone) dihydrochloride, [ 14 C]-mitoguazone has been prepared in three steps from potassium[1- 14 C]-acetate in an overall radiochemical yield of 16%. The key steps in this procedure are the formation of the sodium salt of[acetone-2- 14 C]-methylsulfinylacetone, and Pummerer rearrangement to the [ 14 C] labelled hermithioacetal, which is trapped with two equivalents of aminoguanidine to afford the desired [ 14 C]-mitoguazone. (Author)

  7. Synthesis of 14C-labelled butoxyethoxyethanol

    International Nuclear Information System (INIS)

    Thijssen, J.B.A.; Janssen, C.G.M.; Verluyten, W.L.M.; Heykants, J.J.P.

    1986-01-01

    Butoxyethoxyethanol, an organic solvent used as carrier in the levamisole pour-on formulation, was synthesized via a Makosza etherification of 1- 14 C-labelled bromobutane with mono tetrahydropyranyl (T.H.P.) protected diethylene glycol and subsequent removal of the T.H.P. protecting group. The compounds' synthetic yield was 88.8%; it had a specific activity of 32.5 mCi/mmol. The reaction product was radiochemically pure (99.6%) according to high-performance liquid chromatography and thin-layer chromatography in three solvent systems. (author)

  8. 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)

  9. Human folate metabolism using 14C-accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Arjomand, A; Bucholz, B A; Clifford, A J; Duecker, S R; Johnson, H; Schneider, P D; Zulim, R A.

    1999-01-01

    Folate is a water soluble vitamin required for optimal health, growth and development. It occurs naturally in various states of oxidation of the pteridine ring and with varying lengths to its glutamate chain. Folates function as one-carbon donors through methyl transferase catalyzed reactions. Low-folate diets, especially by those with suboptimal methyltransferase activity, are associated with increased risk of neural tube birth defects in children, hyperhomocysteinemic heart disease, and cancer in adults. Rapidly dividing (neoplastic) cells have a high folate need for DNA synthesis. Chemical analogs of folate (antifolates) that interfere with folate metabolism are used as therapeutic agents in cancer treatment. Although much is known about folate chemistry, metabolism of this vitamin in vivo in humans is not well understood. Since folate levels in blood and tissues are very low and methods to measure them are inadequate, the few previous studies that have examined folate metabolism used large doses of radiolabeled folic acid in patients with Hodgkins disease and cancer (Butterworth et al. 1969, Krumdieck et al. 1978). A subsequent protocol using deuterated folic acid was also insufficiently sensitive to trace a physiologic folate dose (Stites et al. 1997). Accelerator mass spectrometry (AMS) is an emerging bioanalytical tool that overcomes the limitations of traditional mass spectrometry and of decay counting of long lived radioisotopes (Vogel et al. 1995). AMS can detect attomolar concentrations of 14 C in milligram-sized samples enabling in vivo radiotracer studies in healthy humans. We used AMS to study the metabolism of a physiologic 80 nmol oral dose of 14 C-folic acid (1/6 US RDA) by measuring the 14 C-folate levels in serial plasma, urine and feces samples taken over a 150-day period after dosing a healthy adult volunteer

  10. The bomb 14C transient in the Pacific Ocean

    Science.gov (United States)

    Rodgers, Keith B.; Schrag, Daniel P.; Cane, Mark A.; Naik, Naomi H.

    2000-04-01

    A modeling study of the bomb 14C transient is presented for the Pacific Ocean. A primitive equation ocean circulation model has been configured for a high-resolution domain that accounts for the Indonesian Throughflow (ITF). Four separate runs were performed: (1) seasonal forcing with 20 Sv of ITF transport, (2) seasonal forcing with 10 Sv of ITF transport, (3) seasonal forcing with no ITF transport, and (4) interannual forcing with 15 Sv of ITF transport. This study has two main objectives. First, it is intended to describe the time evolution of the bomb 14C transient. This serves as a tool with which one can identify the physical processes controlling the evolving bomb 14C distribution in the Pacific thermocline and thus provides an interpretive framework for the database of Δ14C measurements in the Pacific. Second, transient tracers are applied to the physical oceanographic problem of intergyre exchange. This is of importance in furthering our understanding of the potential role of the upper Pacific Ocean in climate variability. We use bomb 14C as a dye tracer of intergyre exchange between the subtropical gyres and the equatorial upwelling regions of the equatorial Pacific. Observations show that while the atmospheric Δ14C signal peaked in the early to mid-1960s, the Δ14C levels in the surface water waters of the subtropical gyres peaked near 1970, and the Δ14C of surface waters in the equatorial Pacific continued to rise through the 1980s. It is shown that the model exhibits skill in representing the large-scale observed features observed for the bomb 14C transient in the Pacific Ocean. The model successfully captures the basin-scale inventories of bomb 14C in the tropics as well as in the extratropics of the North Pacific. For the equatorial Pacific this is attributed to the model's high meridional resolution. The discrepancies in the three-dimensional distribution of bomb 14C between the model and data are discussed within the context of the dynamical

  11. Synthesis of pinacolyl [14C]methylphosphonochloridate

    International Nuclear Information System (INIS)

    Horvat, J.; Keglevic, D.; Klaic, B.; Kveder, S.; Ladesic, B.; Cosic, M.; Zupanc, S.

    1982-01-01

    A three-step synthetic route to pinacolyl [ 14 C]methylphosphonochloridate (3) from [ 14 C]methyl iodide is described. Condensation of sodium di-n-butyl phosphite with [ 14 C]methyl iodide gave di-n-butyl [ 14 C]methylphosphonate (1) which was converted into [ 14 C]methylphosphonic dichloride (2) by prolonged refluxing with thionyl chloride. Reaction of 2 with pinacolyl alcohol in the presence of N,N-di-n--propylaniline as the base afforded the title compound 3. The radiochemical yield of redistilled 3 was 34,2% based on 1, and the overall radiochemical yield was 20,0% from [ 14 C]methyl iodide. (author)

  12. Whole body autoradiography with mice using 14C-thymidine

    International Nuclear Information System (INIS)

    Hruby, R. et al

    1982-06-01

    Whole body autoradiography was performed using common histology equipment. Results were useful with some restrictions. 14C-thymidine and/or itsmetabolites were found in those tissues with high rate of mitosis. (Author)

  13. 14C-urea breath test for the detection of Helicobacter pylori

    International Nuclear Information System (INIS)

    Veldhuyzen van Zanten, S.J.; Tytgat, K.M.; Hollingsworth, J.; Jalali, S.; Rshid, F.A.; Bowen, B.M.; Goldie, J.; Goodacre, R.L.; Riddell, R.H.; Hunt, R.H.

    1990-01-01

    The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14 C-urea breath test which uses 5 microCi 14 C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared the outcome of the breath test to the results of histology and culture of endoscopically obtained gastric biopsies in 84 patients. The breath test discriminated well between the 50 positive patients and the 34 patients negative for Helicobacter pylori: the calculated sensitivity was 100%, specificity 88%, positive predictive value 93%, and negative predictive value 100%. Treatment with bismuth subsalicylate and/or ampicillin resulted in lower counts of exhaled 14 CO 2 which correlated with histological improvement in gastritis. The 14 C-urea breath test is a better gold standard for the detection of Helicobacter pylori than histology and/or culture

  14. Clinical investigation of 14C-urea breath test

    International Nuclear Information System (INIS)

    Yu Yongli; Zhu Ruisen; Ji Hong; Luo Quanyong

    2000-01-01

    To investigate clinical value of 14 C-urea breath test ( 14 C-UBT) for the diagnosis of Helicobacter pylori(Hp), 70 patients were both performed gastroscopy (taking gastric mucosae biopsy for rapid urease test and histology) and 14 C-UBT (some patients by Hp-IgG or DNAHp test also) within two days. The positive cases of both rapid urease test and histology was defined as 'gold standard' of Hp-positive, whereas the negative cases of both rapid urease test and histology as 'gold standard' of Hp-negative. The sensitivity of 14 C-UBT was 93.2%, the specificity 73.1%, and the diagnostic accuracy 85.7%. The difference (comparing with 'gold standard') was not marked (x 2 = 0.9 0.05(1) 2 = 3.84, P>0.05). But the diagnostic accuracy of 14 C-UBT (85.7%) and Hp-IgG (50%) had a marked difference (x 2 13.80>x 0.01(1) 2 = 6.64, P 14 C-UBT was easy to operate, reliable and suitable for clinical application

  15. A highly sensitive and specific assay for vertebrate collagenase

    International Nuclear Information System (INIS)

    Sodek, J.; Hurum, S.; Feng, J.

    1981-01-01

    A highly sensitive and specific assay for vertebrate collagenase has been developed using a [ 14 C]-labeled collagen substrate and a combination of SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and fluorography to identify and quantitate the digestion products. The assay was sufficiently sensitive to permit the detection and quantitation of collagenase activity in 0.1 μl of gingival sulcal fluid, and in samples of cell culture medium without prior concentration. The assay has also been used to detect the presence of inhibitors of collagenolytic enzymes in various cell culture fluids. (author)

  16. Synthesis of (/sup 14/C)Zolpidem

    Energy Technology Data Exchange (ETDEWEB)

    Allen, J.; Tizot, A.

    1986-04-01

    The synthesis of (/sup 14/C)Zolpidem, a new hypnotic agent having a non-benzodiazepine structure, is described. This compound was synthesised in a 64% overall radiochemical yield from potassium (/sup 14/C)cyanide and with a specific radioactivity of 56 mCi/mmol. It was used for pharmacokinetic and drug metabolism studies.

  17. Synthesis of [14C]Zolpidem

    International Nuclear Information System (INIS)

    Allen, J.; Tizot, A.

    1986-01-01

    The synthesis of [ 14 C]Zolpidem, a new hypnotic agent having a non-benzodiazepine structure, is described. This compound was synthesised in a 64% overall radiochemical yield from potassium [ 14 C]cyanide and with a specific radioactivity of 56 mCi/mmol. It was used for pharmacokinetic and drug metabolism studies. (author)

  18. Synthesis of 14C-labelled milrinone

    International Nuclear Information System (INIS)

    Duncan, D.R.; Johnston, D.; Andrews, R.S.

    1985-01-01

    A synthetic procedure for producing 14 C-labelled milrinone, a potent new cardiotonic agent, is described. The synthesis was achieved in two steps from 1-(4-pyridyl)propan-2-one utilising [2- 14 C]cyanoacetamide as the source of the radiolabel. The overall chemical yield was 46% and the radiochemical yield 35%. (author)

  19. Formation of 14C-asparagine from 14C-precursor in mulberry leaves

    International Nuclear Information System (INIS)

    Yamashita, Tadaaki

    1981-01-01

    Since a remarkable accumulation of asparagine in the young leaves of mulberry has been observed, the formation of 14 C-asparagine from 14 C-labeled substrates in young leaves was examined in comparison with that in the mature leaves. 14 C-aspartic acid and 14 C-succinic acid expected as active precursors for asparagine biosynthesis, and 14 C-sucrose as respiratory substrates were fed respectively to the disks of young or mature leaves of mulberry. Although 14 C-succinic acid was actively converted to 14 C-asparagine, no significant amount of 14 C-asparagine was formed from 14 C-aspartic acid in two hours of feeding period. The rate of formation of 14 C-asparagine from 14 C-succinic acid in the mature leaves was slightly higher than that in the young leaves. Amino acids other than asparagine acquired 14 C from 14 C-labeled substrates were mainly aspartic acid, glutamic acid, alanine and ν-amino butyric acid in both of the leaves. Intending to accelerate the formation of asparagine in the leaves, ammonium ion was supplied to culturing solution as only source of nitrogen and plants were grown for two weeks in that solution before 14 C-labeled substrates feeding experiments. Supplying of ammonium ion brought about enhanced accumulation of asparagine in the young leaves, and caused remarkable formation of 14 C-asparagine from 14 C-aspartic acid in both of the leaves. However, the rate of 14 C-asparagine formation from 14 C-aspartic acid in the young leaves did not exceed that in the mature leaves. (author)

  20. Preparation of arginine (guanide 14C)

    International Nuclear Information System (INIS)

    Pichat, L.; Baret, C.

    1960-01-01

    Reaction of anhydrous ammoniac at 800 deg. C on 14 CO 3 Ba gives rise to barium cyanamide 14 C with a yield of about 98 per cent. Addition on H 2 S on cyanamide 14 C leads to thiourea 14 C with a 85 per cent yield, which is quantitatively transformed into S-ethyl-isothiouronium iodide by treatment with methyl iodide. This 14 C-isothiouronium salt is used to introduce 14 C guanide group in α-N-tosyl-ornithine; tosyl group in α-N-tosyl-arginine thus obtained is then removed by hydrolysis with hydrochloric acid. Arginine is separated as flavianic acid salt and is purified on exchange resin Dowex-50. The overall yield based on 14 CO 3 Ba is 25 per cent. (author) [fr

  1. Measurements of in situ produced 14C in terrestrial rocks

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  2. 14C concentrations in tree stems, 1

    International Nuclear Information System (INIS)

    Kikata, Yoji; Yonenobu, Hitoshi; Morishita, Fumio; Hattori, Yoshiaki; Marsoen, S.N.

    1993-01-01

    The 14 C concentrations in trees sampled at various latitudes were measured with a Tandetron Accelerator Mass Spectrometer at Nagoya University. The growing periods of the parts for 14 C measurements were estimated by the relationship between meteorological conditions and the appearance of anatomical features of annual rings such as false rings, latewood formation, and so on. The following results were obtained: 1. The latitude dependence of the 14 C variation is found in tree stems as well as in the atmosphere. 2. The 14 C concentrations in tree stems are almost equal to those in the atmosphere at the latitude where the tree had grown and at the time when the sampled section is formed. Therefore the 14 C concentrations in the atmosphere are estimated by those of the tree stems. 3. The time when the 14 C concentration in the tree showed its maximum value has difference of 1 - 2 years with that of the latitude where the tree had grown. 4. This phenomena seemed to be related closely with the mechanism of global mixing of 14 CO 2 produced by atmospheric nuclear weapon tests. This mechanism causes a time lag of 14 C variation between northern and southern hemisphere. (author)

  3. Biokinetics and radiation dosimetry of 14C-labelled triolein, urea, glycocholic acid and xylose in man. Studies related to nuclear medicine 'breath tests' using accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Gunnarsson, Mikael

    2002-08-01

    14 C-labelled substances have been used in biomedical research and clinical medicine for over 50 years. Physicians and scientists however, often hesitate to use these substances in patients and volunteers because the radiation dosimetry is unclear. In this work detailed long-term biokinetic and dosimetric estimation have been carried out for four clinically used 14 C-breath tests: 14 C-triolein (examination of fat malabsorption), urea (detection of Helicobacter pylori infection in the stomach), glycocholic acid and xylose (examination of bacterial overgrowth in the small intestine) by using the highly sensitive accelerator mass-spectrometry (AMS) technique. The AMS technique has been used to measure low 14 C concentrations in small samples of exhaled air, urine, faeces and tissue samples and has improved the base for the estimation of the absorbed dose to various organs and tissues and the effective dose to man. The high sensitivity of the AMS system has also made it possible to perform 14 C breath tests on patient groups which were earlier subject for restriction (e.g. small children). In summary, our results show that for adult patients - and in the case of 14 C-urea breath test also for children down to 3 years of age - the dose contributions are comparatively low, both described as organ doses and as effective doses. For adults, the latter is: 14 C-glycocholic acid - 0.4 mSv/MBq, 14 C-triolein - 0.3 mSv/MBq, 14 C-xylose - 0.1 mSv/MBq and 14 C-urea - 0.04 mSv/MBq. Thus, from a radiation protection point of view there is no reason for restrictions in using any of the 14 C-labelled radiopharmaceutical included in this work in the activities normally used (0.07-0.2 MBq for a 70 kg patient)

  4. 14C levels in Trombay environment

    International Nuclear Information System (INIS)

    Doshi, G.R.; Sadarangani, S.H.; Krishnamoorthy, T.M.

    1994-01-01

    The passive air sampling method has been used to measure the spatial distribution of the specific activity of 14 C in air samples collected within the Trombay complex. The samples collected within radial distance of about 0.5 km from Cirus showed 3 to 5 times higher specific activity of 14 C over the natural background level of 6.2 pCi/g C. The same decreased with the distance and approached the value of natural level at the site boundary (1.6 km). The specific activity of 14 C in leaf samples collected within the complex showed the similar pattern. (author). 6 refs., 2 tabs

  5. Biodegradation mechanism of linear alkylbenzenesulfonate-14C

    International Nuclear Information System (INIS)

    Kubodera, Tadayoshi; Muto, Toshio; Yamamoto, Tatsuo

    1978-01-01

    The biodegradation of linear alkylbenzenesulfonate- 14 C (LAS- 14 C) tagged with 14 C at the linear side chain was studied on activated sludge by tracer method in addition to the methylene blue method which is widely employed in the biodegradation of LAS. It was found that there were three periods of rapid adsorption period, acclimation period, and degradation process. The radiolysis of dodecylbenzenesulfonate was studied on irradiating by 5000 Ci 60 Co source. The decomposition products were identified by GLC and GC-MS spectrometry after desulfonation. 1-Tetralone, 1-indanone, 4-methyl-1-tetralone, naphthalene et al. were found in them. (author)

  6. Forensic applications of {sup 14}C at CIRCE

    Energy Technology Data Exchange (ETDEWEB)

    Marzaioli, F., E-mail: fabio.marzaioli@unina2.it [CIRCE, Dipartimento di Scienze Ambientali, Seconda Universita degli Studi di Napoli and INNOVA, Via Vivaldi 43, 81100 Caserta (Italy); Fiumano, V., E-mail: vittoriofiumano85@libero.it [CIRCE, Dipartimento di Scienze della Vita, Seconda Universita degli Studi di Napoli and INNOVA, Via Vivaldi 43, 81100 Caserta (Italy); Capano, M., E-mail: manuela.capano@unina2.it [CIRCE, Dipartimento di Studio delle Componenti Culturali del Territorio, Seconda Universita degli Studi di Napoli and INNOVA, Piazza S. Francesco, 81055 Santa Maria Capua Vetere, Caserta (Italy); Passariello, I., E-mail: isabella.passariello@unina2.it [CIRCE, Dipartimento di Scienze Ambientali, Seconda Universita degli Studi di Napoli and INNOVA, Via Vivaldi 43, 81100 Caserta (Italy); Cesare, N.De., E-mail: nicola.decesare@unina2.it [CIRCE, Dipartimento di Scienze della Vita, Seconda Universita degli Studi di Napoli and INNOVA, Via Vivaldi 43, 81100 Caserta (Italy); Terrasi, F., E-mail: filippo.terrasi@unina2.it [CIRCE, Dipartimento di Scienze Ambientali, Seconda Universita degli Studi di Napoli and INNOVA, Via Vivaldi 43, 81100 Caserta (Italy)

    2011-12-15

    The decreasing trend of the radiocarbon pulse produced during the atmospheric tests of nuclear weapons (bomb-carbon) coupled with high sensitivity accelerator mass spectrometry (AMS) measurements, drastically increased the precision of radiocarbon age determinations since the second part of the sixties, allowing the application of radiocarbon AMS to a wide range of studies previously not directly involving conventional radiocarbon dating (i.e. food authenticity, forensic, biochemistry). In the framework of authenticity evaluation of artworks, high precision radiocarbon ({sup 14}C) AMS measurements ({Delta}R/R < 0.3%) reduce the conventional uncertainty of the dating to few decades, allowing precise age estimation of materials containing carbon (C). The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) during its activity on AMS {sup 14}C dating achieved high precision measurements opening the opportunity to these kinds of applications. This paper presents the main results obtained from radiocarbon measurements on a set of bone samples analyzed for the determination of the post-mortem interval in the framework of an unsolved case investigated by the Rome prosecutor office. The chronological characterization of the wooden support of the 'Acerenza portrait' is also presented with the aim to evaluate its age and to further investigate the possibility to attribute this artwork to Leonardo da Vinci. Bomb-{sup 14}C dating on the lipid and collagen fractions of bones allows the evaluation of the year of the death of the individuals by means of ad hoc calibration data sheet with the typical few years precision and difference between collagen apparent age and the year of death appeared in agreement with the age of one individual estimated by dating of tooth collagen. Conventional radiocarbon dating on both wood and wood extracted cellulose leads to an estimation of the portrait wood board age (2{sigma}) of 1459-1524 AD (57% relative

  7. [14C]Virginiamycin residues in eggs

    International Nuclear Information System (INIS)

    Corpet, D.E.; Baradat, M.; Bories, G.F.

    1988-01-01

    Laying hens were fed ab libitum a diet supplemented at 40, 10, and 0 mg/kg with [ 14 C]virginiamycin, to determine whether or not virginamycin or its metabolites were transferred to the eggs. About 0.05% of the ingested 14 C dose was recovered in the eggs. Radiolabeled residues expressed in terms of virginiamycin equivalents were found to be 5.1 ng/g in the albumen and 31.8 ng/g in the yolk from hens fed a 10 mg/kg diet. No antibiotic activity could be detected in the eggs. Tentative identifications showed that in the albumen about 17% of the 14 C behaved chromatographically like virginiamycin and 18% was associated to the ovalbumin. In the yolk 31% of the 14 C was associated to proteins, 58% to fatty acids, and 4% to unsaponifiable matter

  8. 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)

  9. 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).

  10. Uptake and distribution of 14C during and following exposure to [14C]methyl isocyanate

    International Nuclear Information System (INIS)

    Ferguson, J.S.; Kennedy, A.L.; Stock, M.F.; Brown, W.E.; Alarie, Y.

    1988-01-01

    Guinea pigs were exposed to [ 14 C]methyl isocyanate ( 14 CH 3 -NCO, 14 C MIC) for periods of 1 to 6 hr at concentrations of 0.5 to 15 ppm. Arterial blood samples taken during exposure revealed immediate and rapid uptake of 14 C. Clearance of 14 C was then gradual over a period of 3 days. Similarly 14 C was present in urine and bile immediately following exposure, and clearance paralleled that observed in blood. Guinea pigs fitted with a tracheal cannula and exposed while under anesthesia showed a reduced 14 C uptake in blood indicating that most of the 14 C MIC uptake in normal guinea pigs occurred from retention of this agent in the upper respiratory tract passages. In exposed guinea pigs 14 C was distributed to all examined tissues. In pregnant female mice similarly exposed to 14 C MIC, 14 C was observed in all tissues examined following exposure including the uterus, placenta, and fetus. While the form of 14 C distributed in blood and tissues has not yet been identified, these findings may help to explain the toxicity of MIC or MIC reaction products on organs other than the respiratory tract, as noted by several investigators

  11. High order depletion sensitivity analysis

    International Nuclear Information System (INIS)

    Naguib, K.; Adib, M.; Morcos, H.N.

    2002-01-01

    A high order depletion sensitivity method was applied to calculate the sensitivities of build-up of actinides in the irradiated fuel due to cross-section uncertainties. An iteration method based on Taylor series expansion was applied to construct stationary principle, from which all orders of perturbations were calculated. The irradiated EK-10 and MTR-20 fuels at their maximum burn-up of 25% and 65% respectively were considered for sensitivity analysis. The results of calculation show that, in case of EK-10 fuel (low burn-up), the first order sensitivity was found to be enough to perform an accuracy of 1%. While in case of MTR-20 (high burn-up) the fifth order was found to provide 3% accuracy. A computer code SENS was developed to provide the required calculations

  12. An improved synthesis of 14C labelled glycerol using sodium borohydride

    International Nuclear Information System (INIS)

    Chander, H.; Ramamurthy, T.V.; Viswanathan, K.V.

    1987-01-01

    [1- 14 C]Glyceric acid has been reduced to [1(3)- 14 C]glycerol in high yields via the methyl ester of [1- 14 C]glyceric acid by sodium borohydride in the presence of t-butyl alcohol and methanol. The importance of the procedure is highlighted in relation to other procedures involving lithium aluminium hydride reduction. (author)

  13. Radioactive waste with 14C in Argentina

    International Nuclear Information System (INIS)

    Di Lello, D.S.

    2009-01-01

    14 C is a long half-life radioisotope, which is present in radioactive waste generated during the operation and decommissioning of nuclear power plants. 14 C can also be found in waste generated by medical diagnostic laboratories or any one generated by fields that deal with research and development (mainly connected with the biochemists area). According to international precedents the disposal of 14 C based on the final amount found in radioactive waste and its chemical form have conditioned the design and operation of the facilities (either because of the amount of it or the chemical form in which 14 C was present). We have to take into account that the design of facilities for radioactive waste disposal is included among the obligations of the National Radioactive Waste Management Program (PNGRR). It is absolutely necessary to count with enough information about the characteristics of any waste containing 14 C that is generated in Argentina, in order to be able to fulfil the requirements previously mentioned. The main characteristics of interest in the frame of the present project are: a) the principal reactions that take place for the formation of 14 C; b) The specific concentration of activity in materials where this radio nuclei is formed or is accumulated; c) To know which is the current step in the process of managing these wastes (in Argentina and all over the world). Either if it refers to bulk or conditioned storage, inside the generating facility; d) Transportation possibilities of 14 C under these conditions; e) The accumulated volume and the generation rate of this kind of waste in Argentina. This paper presents an initial collection and evaluation of the information related to the characteristics already mentioned, having gathered published material from the literature and information in the PNGRR up to this moment. The description of the characteristics of the radioactive waste containing 14 C from nuclear power plants, hospitals and research and

  14. How accurate is the 14C method

    International Nuclear Information System (INIS)

    Nydal, R.

    1979-01-01

    Radiocarbon daters have in recent years focussed their interest on accuracy and reliability of 14 C dates. The use of dates for resolving fine chronological structures that are not dateable otherwise has stressed this point. The total uncertainty in dating an event is composed of errors relating to dating of the sample, i.e. uncertainty in measured quantities, deviations from assumed content of 14 C in material when alive; and errors related to quality of sample material, i.e. contamination from carbon of different age, diffuse context between sample and event. Statistical variability in counting of 14 C activity gives the most important contribution to measurement uncertainty - increasing with age and shortage of sample material. Corrections for isotopic fractionation and reservoir effects must be performed, and - most important when dates are compared with historical ages - the dendrochronological calibration will correct for past variations in the atmospheric 14 C content. Future improvement of dating precision can however only be obtained by the combined efforts of both daters and submitters of samples, thus minimizing errors related to selection and handling of sample material as well as those related to the 14 C method and measurements. (Auth.)

  15. Human Vitamin B12 Absorption and Metabolism are Measured by Accelerator Mass Spectrometry Using Specifically Labeled 14C-Cobalamin

    International Nuclear Information System (INIS)

    Carkeet, C; Dueker, S R; Lango, J; Buchholz, B A; Miller, J W; Green, R; Hammock, B D; Roth, J R; Anderson, P J

    2006-01-01

    There is need for an improved test of human ability to assimilate dietary vitamin B 12 . Assaying and understanding absorption and uptake of B 12 is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry (AMS) is uniquely suited for assessing absorption and kinetics of 14 C-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of carbon-14 ( 14 C) in microliter volumes of biological samples, with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B 12 in the range of normal dietary intake. The B 12 used was quantitatively labeled with 14 C at one particular atom of the DMB moiety by exploiting idiosyncrasies of Salmonellametabolism. In order to grow aerobically on ethanolamine, S. entericamust be provided with either pre-formed B 12 or two of its precursors: cobinamide and dimethylbenzimidazole (DMB). When provided with 14 C-DMB specifically labeled in the C2 position, cells produced 14 C-B 12 of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 mg, 2.2 KBq/59 nCi) of purified 14 C-B 12 was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B 12 assimilation

  16. Quantitation of 14C-oxaliplatin concentrations in human serum samples by using accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Kobayashi, Takeshi; Toyoguchi, Teiko; Kato, Kazuhiro; Tokanai, Fuyuki; Shiraishi, Tadashi

    2013-01-01

    The understanding of human pharmacokinetics is important for development of new drugs. Microdosing studies have been proposed as means of obtaining human pharmacokinetics information at early stages of drug development. Accelerator mass spectrometry (AMS) has high detection sensitivity and is expected to play an important role in microdose trials. In this study, we used the AMS microdosing facility at Yamagata University to measure the concentration of 14 C in 14 C-oxaliplatin-spiked serum samples. The calibration curve of 14 C concentration in serum was linear, and the correlation coefficient was 0.9994. The precision, accuracy, and stability values obtained (freeze and thaw cycles, and short- and long-term stability) satisfied the criteria. The mean background 14 C concentrations in samples of 6 healthy Japanese volunteers were 1.635dpm/mL in blood and 0.56dpm/mL in plasma. These results suggest the suitability of AMS-based quantitation for analyzing samples from microdosing studies. (author)

  17. Placental transfer of 14C-hexoprenaline

    International Nuclear Information System (INIS)

    Lipshitz, J.; Broyles, K.; Whybrew, W.D.; Ahokas, R.A.; Anderson, G.D.

    1982-01-01

    The placental transfer of a single intravenous injection of 14 C-hexoprenaline was studied in eight pregnant New Zealand white rabbits. Maternal and fetal blood was sampled intermittently for 60 minutes after the injection. An initial rapid decrease in the levels of 14 C-hexoprenaline in maternal blood was followed by a second slower phase, whereas fetal heart rate after the administration of a single maternal intravenous injection of hexoprenaline in the treatment of fetal distress is due to the action on the uterus and/or on maternal cardiovascular function, and not to direct stimulation of the fetus

  18. Organic compounds preparation with 14 C

    International Nuclear Information System (INIS)

    Shirvani, Gholam Hossein.

    1996-09-01

    Active urea is a basic reagent for the synthesis of active uric-8- 14 C acid. In our manner, activated Barium carbonate with specified activity was placed in a special furnace with ability of passing gases. Then, ammonia gas was passed through it at about 850 Degree C to obtain Barium Cyanamide. Reaction of the produced compound with CO 2 , and then acidification of the mixture, gave activated urea. Condensation of the urea with Ethylcyanoacetate, produce 6-Aminouracil which upon nitrosation, reduction and then condensation with urea, the desired Uric-8- 14 C acid was synthesized. (author). 148 refs.,

  19. Synthesis of 14C-labeled stepholidine

    International Nuclear Information System (INIS)

    Yang Liu; Zhang Xin

    1988-01-01

    L-Tetrahydroprotoberberine (THPB) alkaloids are dopamine-receptor antagonists. Stepholidine has been shown to possess the strongest pharmacological effects among the THPB alkaloids studied. In order to study its metabolism and the mode of action of the drug, a radiolabeled stepholidine was required. We report here the synthesis of 14 C-labeled stepholidine by Mannich condensation of 7-benzyloxy-1-(4-benzyloxy-3-hydroxy-benzyl)-6-methoxy-1,2,3,4-tetrahydroisoquinoline with ( 14 C)formaldehyde followed by methylation and debensylation in 32% radiochemical yield. (author)

  20. Analysis of Δ14C variations in atmosphere

    International Nuclear Information System (INIS)

    Simon, J.; Sivo, A.; Richtarikova, M.; Holy, K.; Polaskova, A.; Bulko, M.; Hola, O.

    2005-01-01

    The Δ 14 C in the atmosphere have been measured and studied in two localities of Slovakia. The accomplished analysis proved the existence of the annual variations of the Δ 14 C with the attenuating amplitude and decreasing mean value. It seems to be logical and physically correct to describe the Δ 14 C time-dependence by the equation: y = Ae -at + Be -bt cos(ω 1 t + (φ)). The coefficients A, a, B, b, (φ) are listed in the table for both the localities. The observed variations of the Δ 14 C have a maximum in summer and minimum in winter .Probably it is caused by the higher requirement of the heat supply in winter season which is connected directly with the fossil CO 2 emissions and more intensive Suess effect. Summer maximum could be explained by the combination of the lower CO 2 emission rate and higher turbulent transport of the stratospheric 14 C to the troposphere. Using the Fourier harmonic analysis the amplitude spectra of the average annual variations were plotted. The obtained result shows that the variations have the high degree of symmetry. Furthermore, the obtained basic frequency ω 1 = 2π/12 [month -1 ] proves that the cyclic processes with the period of T = 12 [month] have a major influence on the 14 C amount in the troposphere. The presence of some higher-order harmonics is significant, but a physical interpretation has not yet been clear. In addition to the main frequency there are presented also 2ω 1 and 3ω 1 in Bratislava and 4ω 1 in Zlkovce data-set. The long-time average of the Δ 14 C in Zlkovce during years 1995-2004 is higher of about 6.6 o / oo than in Bratislava. It represents an unique evidence that the local CO 2 pollution affects the 14 C activity . The correlation on the level R 2 = 0,43 was found between Bratislava and Zlkovce atmospheric Δ 14 C data. (authors)

  1. Monitoring of the 14C activity in the atmosphere

    International Nuclear Information System (INIS)

    Svingor, E.; Molnar, M.; Futo, I.; Rinyu, L.

    2006-01-01

    Complete text of publication follows. The distribution of atmospheric radiocarbon has been extensively investigated both in the Northern and Southern Hemisphere as well as in the Tropics for a number of decades. Systematic global observations of 14 CO 2 in the troposphere were made during and after atmospheric nuclear weapon tests in the 1950s and 1960s by several laboratories. Nowadays the monitoring of 14 C in regions adjacent to nuclear power plants (NPP) or sites of land-filled radioactive wastes has growing importance in determining the frequency and activity of anthropogenic 14 C released to the environment. On the other hand, the depletion of 14 C in the atmosphere gives information about the regional fossil fuel CO 2 contributions (Figure 1., Prague-Bulovka). The 14 C activity of the atmosphere has been monitored in the vicinity of Paks NPP by sampling environmental air monthly since 1994. Four differential sampling units collect air samples less than 2 km away from the 100- m-high stacks of Paks NPP (A-type stations), and for reference a sampler is operated at a station (B24) ca. 30 km away from Paks NPP. The highest 14 C values were measured at the site located less than 1km away from Paks NPP. The influence of the 14 C discharge in the environment decreases rapidly with the distance from the source and under normal operating conditions the effect of Paks NPP is negligible at a distance of 2.5km. In Figure 1. we have compared our data for Paks NPP measured during the time span of 2000 - 2005 with data from different European monitoring stations. (The 14 C activities are given in Δ values: Δ 14 C(% (A sample /A standard -1) x 1000.) In 2000-2001 the excess 14 C at Paks NPP compared to the B24 was 5-10 (per mille) but its Δ value didn't exceed the tropospheric background (1). With the growing traffic the inactive CO 2 emission (Suess effect) exceeded the influence of the NPP (2). After a cleaning tank incident at unit 2 of Paks NPP in April 2003 a 5

  2. 14C tebuconazole degradation in Colombian soils.

    Science.gov (United States)

    Mosquera, C S; Martínez, M J; Guerrero, J A

    2010-01-01

    Tebuconazole is a fungicide used on onion crops (Allium Fistulosum L) in Colombia. Persistence of pesticides in soils is characterized by the half-life (DT50), which is influenced by their chemical structure, the physical and chemical properties of the soil and the previous soil history. Based on its structural and chemical properties, tebuconazole should be expected to be relatively persistent in soils. Laboratory incubation studies were conducted to evaluate persistence and bond residues of 14C tebuconazole in three soils, two inceptisol (I) and one histosol (H). Textural classifications were: loam (101), loamy sand (102) and loam (H03), respectively. Data obtained followed a first-order degradation kinetics (R2 > or = 0.899) with DT50 values between 158 and 198 days. The production of 14CO2 from the 14C-ring-labelled test chemicals was very low and increased slightly during 63 days in all cases. The methanol extractable 14C-residues were higher than aqueous ones and both decreased over incubation time for the three soils. The formation of bound 14C-residues increased with time and final values were 11.3; 5.55 and 7.87% for 101, 102 and H03 respectively. Soil 101 showed the lowest mineralization rate and the highest bound residues formation, which might be explained by the clay fraction content. In contrast, an inverse behavior was found for soils 102 and H03, these results might be explained by the higher soil organic carbon content.

  3. Synthesis of /sup 14/C-labeled felbamate from phenylacetic-(methylene-/sup 14/C) acid

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Y.M.; Kucharczyk, N.; Sofia, R.D.

    1986-05-01

    A synthetic procedure for the preparation of 2-phenyl-1,3-propanediol-2-/sup 14/C dicarbamate, starting with phenylacetic-(methylene-/sup 14/C) acid was developed. The procedure from phenylacetic acid to 2-phenyl-1,3-propanediol dicarbamate has four steps via phenylmalonic acid and 2-phenyl-1,3-propanediol. The overall yield of all four steps was 28%.

  4. Study of the reaction 14 C (p,p) 14 C

    International Nuclear Information System (INIS)

    Murillo, G.; Ramirez, J.; Avila, O.; Fernandez, M.; Darden, S.E.; Prior, R.P.; Sen, S.

    1991-04-01

    The study of the elastic scattering of polarized protons in 14 C, it has been very limited. Some angular distributions exists to low energy, as well as measures of excitation functions to several angles for the differential section and the vectorial analyzer power. A detailed study of the elastic scattering of protons by 14 C, it give us experimental information of the excited states in 15 N. The study of these states, is since of considerable interest it is not very easy to obtain a target of 14 C also in a reaction 14 C (p,p) 14 C is possible to obtain information of levels in 15 N to an excitation energy E X >14.95 MeV. (Author)

  5. Distribution of root exudates and mucilage in the rhizosphere: combining 14C imaging with neutron radiography

    Science.gov (United States)

    Holz, Maire; Carminati, Andrea; Kuzyakov, Yakov

    2015-04-01

    exudates. We found that mucilage and 14C concentrations were higher around the young root segments. Mucilage concentration was particularly high in the most apical 3-5 cm of the roots. Drought stress increased 14C exudation relative to C fixation and led to higher mucilage concentrations around roots. However, it remains unclear, whether the lower mucilage concentration around roots grown at higher soil moisture was caused by the faster diffusion of mucilage in wet soils. Therefore, a second experiment was focused on diffusion of mucilage in soil at varying water contents. The diffusion of mucilage in soil was not very sensitive to soil water content. We conclude that mucilage release was higher for plants exposed to drought stress. In summary, the combination of neutron radiography and 14C imaging can successfully be used to visualize and to quantify the distribution of mucilage and root exudates in the rhizosphere of plants grown in soil. References Kroener, E., Zarebanadkouki, M., Kaestner, A., & Carmintati, A. (2014). Nonequilibrium water dynamics in the rhizosphere: How mucilage affects water flow in soils. Water Resources Research, 37. Pausch, J., & Kuzyakov, Y. (2011). Photoassimilate allocation and dynamics of hotspots in roots visualized by 14C phosphor imaging. Journal of Plant Nutrition and Soil Science, 174(1), 12-19.

  6. The clinical value of 14C-urea breath test for diagnosis of helicobacter pylori infection

    International Nuclear Information System (INIS)

    Zhang Shuwen; Zhang Yongxian; Zhang Jinming; Ding Yong; Shao Mingzhe; Liu Zilai; Tian Jiahe

    2003-01-01

    The purpose of this study is to evaluate a rapid microdose 14 C-urea breath test ( 14 C-UBT) with a simplified protocol for detecting the infection of helicobacter pylori (HP). 244 fasting patients with upper gastrointestinal symptoms undergo the 14 C-UBT and 124 cases appear positive. 89 patients of those undergo upper gastrointestinal endoscopy and confirmed as HP infection. The sensitivity and specificity of the 14 C-UBT is 100% when compared with the endoscopy. The test has good diagnostic accuracy with minimal radiation exposure and low cost. Thus, the test is reliable, safe, convenient and cost-effective to clinical use

  7. Placental transfer of 14C-hexoprenaline

    International Nuclear Information System (INIS)

    Lipshitz, J.; Broyles, K.; Whybrew, W.D.; Ahokas, R.A.; Anderson, G.D.

    1982-01-01

    The placental transfer of a single intravenous injection of 14C-hexoprenaline was studied in eight pregnant New Zealand white rabbits. Maternal and fetal blood was sampled intermittently for 60 minutes after the injection. An initial rapid decrease in the levels of 14C-hexoprenaline in maternal blood was followed by a second slower phase, whereas fetal levels remained insignificant. The conclusion, therefore, is that the rapid improvement in fetal heart rate after the administration of a single maternal intravenous injection of hexoprenaline in the treatment of fetal distress is due to the action on the uterus and/or on maternal cardiovascular function, and not to direct stimulation of the fetus

  8. 14C2H4: distribution of 14C-labeled tissue metabolites in pea seedlings

    International Nuclear Information System (INIS)

    Giaquinta, R.; Beyer, E. Jr.

    1977-01-01

    The 14 C-metabolite distribution pattern following 14 C 2 H 4 metabolism in intact pea seedlings (Pisum sativum L.) was determined under various conditions. After a 24 hr exposure to 14 C 2 H 4 , the majority of 14 C-metabolites were water-soluble (60-70%) with lesser amounts in the protein (10-15%), lipid (1%), and insoluble (1-2%) fractions. Ion exchange chromatography of the water-soluble components into basic, neutral, and acidic fractions revealed a 50:40:10 distribution, respectively. Chromatography of the neutral fraction revealed two regions of radioactivity (Rf=0.38) and 0.63 which did not cochromatograph with twenty-two known sugars or neutral metabolites. Chromatograms of the basic fraction contained 3 regions of radioactivity. Similar distribution patterns were noted when 14 C 2 H 4 exposure was followed by a 6 hr air chase or when 5% CO 2 , an antagonist of ethylene action, was present during the exposure. Marked differences in the 14 C-metabolite distribution patterns were obtained when 14 CO 2 was substituted for 14 C 2 H 4 . These results indicate that the metabolic pathway involved in ethylene metabolism is different from that involved in intermediately carbon metabolism. (auth.)

  9. 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

  10. Anthropogenic 14C in the natural (aquatic) environment

    International Nuclear Information System (INIS)

    Begg, F.H.

    1992-11-01

    Increasing global awareness of the radiological significance of 14 C releases from the nuclear and radiochemical industries has resulted in a number of studies within the last decade investigating the atmospheric releases and their effect on the terrestrial biosphere. The basis of this study was to determine the behaviour and environmental distribution of anthropogenically produced 14 C released to the aquatic environment from the nuclear fuel reprocessing plant at Sellafield. Most sampling was undertaken in the Irish Sea with smaller scale studies being carried out in the Bristol Channel and the Grand Union Canal. Within the study area, from Earnse Point 40 km south of Sellafield, northwards to the Clyde Sea area, preliminary studies on intertidal biota samples ie. mussels, winkles and seaweed indicated enriched 14 C specific activities in all the samples relative to the current ambient level of 115.4 pM. The highest activities were observed in the immediate vicinity of the discharge location; mussels with a measured activity of 787 pM, winkles of 613 pM and seaweed of 415 pM. The 14 C specific activity observed at most sites appeared to be organism dependent with mussels>winkles>seaweed. This is the result of differences in the uptake mechanisms of the organisms and indicates that the dissolved inorganic carbon and the particulate material within the water column are enriched in 14 C . However, on analysis of the biogeochemical fractions of the water column, enriched 14 C activities were observed only in the DIC fraction which could explain those activities found in the seaweed but not those in the mussels and winkles. Enriched 14 C activities were found in the phytoplankton, indicating that there is a source of enriched organic particulate material within the water column as a result of photosynthetic uptake of enriched DIC, however this will be a seasonal effect. Nevertheless, this enrichment is still not high enough to support the activities observed in the

  11. Metabolic kinetics and biological effects of radiocarbon (14C)

    International Nuclear Information System (INIS)

    Vasilenko, I.Ya.; Osipov, V.A.; Lyaginskaya, A.M.; Bugryshev, P.F.; Istomina, A.G.; Turova, V.I.; Dement'ev, S.I.; Zhorova, E.S.; Mart'yanov, B.M.; Shal'nova, G.A.; Kuz'mina, T.D.; Shebenko, V.A.; Pomerantseva, M.D.; Ramajya, L.K.

    1988-01-01

    Radiocarbon 14 C is one of the most widespread radionuclides. Increased concentration of anthropogenic 14 C in the biosphere is a problem of considerable hygienic and ecological significance. The paper presents the results of comprehensive studies for years on biokinetics of the main 14 C compounds, inorganic (Na H 14 CO 3 , Na 2 14 CO 3 , K 2 14 CO 3 , Ca 14 CO 3 ) as well as organic ( 14 C-glucose, 14 C-succinic acid, 14 C-glucosamine, 14 C-glycine, 14 C-tryptophane, 14 C-valine, 14 C-palmitic acid, 14 C-stearic acid, 14 C-ethyl alcohol, 14 C-methyl alcohol, 14 C-urea), of 14 C as food constituent and of elementary radiocarbon. The 14 C toxicity is investigated for both acute and chronic small doses received by animals. The nuclide's genetic efficiency is assessed. Based on research evidence, the accumulation multiple and equilibrium time are estimated for long-term 14 C intake by humans. The data may be used for setting genetic standards and estimating an anthropogenic increase of 14 C concentration in the environment. The hazard of anthropogenic radiocarbon is assessed with allowance for further development of nuclear power industry. (author)

  12. 14C accelerator mass spectrometry - applications in archaeology, biomedicine and in the atmospheric sciences

    International Nuclear Information System (INIS)

    Rom, W.

    1990-03-01

    Accelerator mass spectrometry (AMS) is superior to all other analytical techniques in its detection sensitivity of radiocarbon ( 14 C). It has therefore influenced or even laid down the foundations for applications in many fields of science. In the current work, various applications of 14 C AMS are presented through published articles for which the measurements were performed at the Vienna Environmental Research Accelerator (VERA). These articles are embedded into an in-depth discussion about characteristic features of the respective fields, emphasizing the broad range of issues which need to be considered in interdisciplinary research. In archaeology new 14 C dates on equipment of the Iceman ('Oetzi'), the world's oldest intact mummy, show reasonable agreement with dates previously obtained on the Iceman himself (3360-3100 BC). However, several botanical remains from the finding place clearly belong to other time periods, indicating that the discovery site of Oetzi has been used as a mountain pass 1500 yr earlier and also 2000 yr later. Dating on spruce logs from the world's oldest salt mines at Hallstatt, Austria provide evidence that salt mining started 1-2 centuries earlier than previously supposed, i.e. in the 14th to the 13th century BC. Recently, Bayesian mathematics is a frequently used tool in calibrating radiocarbon data. So-called vague or non-informative priors employed in this method may cause severe problems as shown by extensive computer simulations. In biomedicine problems in toxicology and in forensic medicine were investigated. Heterocyclic amines (HAs) are probably the epidemiologically most relevant class of mutagenic and carcinogenic substances since they are produced naturally in cooking protein-rich food. A study of 14 C labeled HAs (MeIQx and PhIP) in rodents and humans, one of the first studies using 14 C-labeled mutagens also in healthy human volunteers, severely calls in question the validity of animal models for assessing heterocyclic

  13. Synthesis of 14C analogue of 1,2-diaryl-[2-14C]-pyrroles

    International Nuclear Information System (INIS)

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

    2007-01-01

    Three 1,2-diaryl pyrroles selective COX-2 inhibitors, 2-(4-fluorophenyl)-5-methyl-1-(4-methylsulfonyl-phenyl)-1H pyrrole, 2-(4-fluorophenyl)-1- [4-(methylsulfonyl) phenyl]-1H-pyrrole and 4-[2-(4-fluorophenyl)-1H-pyrrol-1-yl]benzenesulfon-amide, all three labeled with 14 C in the 2-position were prepared from para-fluoro-benzaldehyde-[carbonyl- 14 C]. (author)

  14. The production of (14C) oxalate during the metabolism of (14C) carbohydrates in isolated rat hepatocytes.

    Science.gov (United States)

    Rofe, A M; James, H M; Bais, R; Edwards, J B; Conyers, R A

    1980-04-01

    Oxalate (14C) was produced during the metabolism of (U-14C) carbohydrates in hepatocytes isolated from normal rats. At 10 mM, the order of oxalate production was fructose > glycerol > xylitol > sorbitol greater than or equal to glucose in the ratio 10 : 4 : 3 : 1 : 1. This difference between oxalate production from fructose and glucose was reflected in their rates of utilisation, glucose being poorly metabolised in hepatocytes from fasted rats. Fructose was rapidly metabolised, producing glucose, lactate and pyruvate as the major metabolites. Glycerol, xylitol and sorbitol were metabolised at half the rate of fructose, the major metabolites being glucose, lactate and glycerophosphate. The marked similarity in the pattern of intermediary metabolites produced by these polyols was not, however, reflected in the rates of oxalate production. Hepatic polyol metabolism resulted in high levels of cytosolic NADH, as indicated by elevated lactate : pyruvate and glycerophosphate : dihydroxyacetone phosphate ratios. The artificial electron acceptor, phenazine methosulphate (PMS) stimulated oxalate production from the polyols, particularly xylitol. In the presence of PMS, the order of oxalate production was fructose greater than or equal to xylitol > glycerol > sorbitol in the ratio 10 : 10 : 6 : 2. The production of glucose, lactate and pyruvate from the polyols was also stimulated by PMS, whereas the general metabolism of fructose, including oxalate production, was little affected. Oxalate (14C) was produced from (1-14C), (2-14C) and (6-14C) but not (3,4-14C) glucose in hepatocytes isolated from non-fasted, pyridoxine-deficient rats. Whilst this labelling pattern is consistent with oxalate being produced by a number of pathways, it is suggested that metabolism via hydroxypyruvate is a major route for oxalate production from various carbohydrates, with perhaps the exception of xylitol, which appears to have an alternative mechanism for oxalate production. The observation that

  15. Evaluation of 14C abundance in soil respiration using accelerator mass spectrometry

    International Nuclear Information System (INIS)

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

    2004-01-01

    To clarify the behavior of 14 C in terrestrial ecosystems, 14 C abundance in soil respiration was evaluated in an urban forest with a new method involving a closed chamber technique and 14 C measurement by accelerator mass spectrometry (AMS). Soil respiration had a higher Δ 14 C than the contemporary atmosphere. This indicates that a significant portion of soil respiration is derived from the decomposition of soil organic matter enriched in 14 C by atmospheric nuclear weapons tests, with a notable time lag between atmospheric 14 C addition and re-emission from soil. On the other hand, δ 14 C in soil respiration demonstrated that 14 C abundance ratio itself in soil-respired CO 2 is not always high compared with that in atmospheric CO 2 because of the isotope fractionation during plant photosynthesis and microbial decomposition of soil organic matter. The Δ 14 C in soil respiration was slightly lower in August than in March, suggesting a relatively high contribution of plant root respiration and decomposition of newly accumulated and/or 14 C-depleted soil organic matter to the total soil respiration in August

  16. Studies on 14C-extractable residue, 14C-bound residue and mineralization of 14C-labeled chlorsulfuron in soils

    International Nuclear Information System (INIS)

    Ye Qingfu; Sun Jinhe; Qi Wenyuan; Wu Jianmin

    2003-01-01

    The purpose of the present study was to investigate 14 C-extractable residue ( 14 C-ER), 14 C-bound residue ( 14 C-BR) and mineralization of 14 C-labeled chlorsulfuron in soils by using isotope technique. The main factors affecting 14 C-BR formation and the distribution pattern of 14 C-BR in humus were also discussed in details. The results were as follows: (1) The 14 C-ER content of 14 C-chlorsulfuron in seven kinds of soil was positively related to soil pH and negatively related to clay content and organic matter content significantly. Moreover. the decrease rate of 14 C-chlorsulfuron parent compound derived from 14 C-ER in soils followed the first order rate reaction, the half-life in Soil 1-Soil 7 were 13.0, 13.1, 17.7, 133.3, 21.8, 22.1, 33.2 days, respectively. It was concluded that soil pH was the main factor affecting the degradation of 14 C-chlorsulfuron. (2) The 14 C-BR content of 14 C-chlorsulfuron in soils increased sharply with the incubation time during the initial 20 days, then changed slowly with time. However, 14 C-BR content during the whole incubation depended on soil types. The order of 14 C-BR content followed Soil 1 > Soil 2, Soil 5 and Soil 6 > Soil 3 > Soil 7 > Soil 4. The maximum values of 14 C-BR content of 14 C-chlorsulfuron in Soil 1-Soil 7 were 53.3%, 40.9%, 37.8%, 16.4%, 42.5%, 41.0% and 31.3% of applied amount. In addition, the 14 C-BR content of 14 C-chlorsulfuron in soils was negatively related to soil pH significantly, and positively related to the clay content. The soil pH was found to be the main factor affecting BR formation of 14 C-chlorsulfuron among the basic properties of soil. (3) During the whole periods of the incubation, the 14 C-BR of 14 C-chlorsulfuron in soils was mainly distributed in fulvic acid and humin. The relative percent of 14 C-BR in fulvic acid was higher than in humin. While the relative percentage of the 14 C-BR in humic acid only account for 2%. It was suggested that fulvic acid played an important role

  17. Synthesis of dexamethasone-4-14C

    International Nuclear Information System (INIS)

    Rao, P.N.; Cessac, J.W.; Hill, K.A.

    1982-01-01

    The bismethylenedioxy (BMD) derivative of dexamethasone 2 was silylated with trimethylchlorosilane and imidazole in dimethylformamide to give the 11β-trimethylsilyloxy BMD derivative 3. The Δ 1 -double bond in 3 was hydrogenated over 5% palladium on carbon to give the Δ 4 -3-oxo steroid 4. Oxidation of 4 with potassium permanganate-sodium metaperiodate gave the seco-acid 5 which on subsequent treatment with acetic anhydride; sodium acetate and triethylamine gave the enol-lactone 6. The enol-lactone 6 was reacted with 14 C-methylmagnesium iodide to give an adduct 7a which on heating at reflux with lithium 2,6-di-t-butylphenoxide in dioxane gave the Δ 4 -3-oxo derivative 8. Compound 8 was heated at reflux with m-iodylbenzoic acid and diphenyl diselenide in toluene to give the Δsup(1,4)-3-oxo steroid 9. The protecting BMD and silyl groups were removed in a single step by reaction with aqueous trifluoroacetic acid containing 2N hydrochloric acid at room temperature to give dexamethasone-4- 14 C 10. (author)

  18. Translocation of 14-C in ponderosa pine seedlings

    Science.gov (United States)

    Robert R. Ziemer

    1971-01-01

    The movement of 14-C from the old needles to the roots, and later to the new needles, was measured in 2-year-old ponderosa pine seedlings. The seedlings were in one of three growth stages at the time of the feeding of 14-CO-2: 9 days before spring bud break with no root activity; 7 days before spring bud break with high root activity; and 7 days after spring bud break...

  19. Validation of {sup 14} C-urea breath test for diagnosis of Helicobacter pylori

    Energy Technology Data Exchange (ETDEWEB)

    Mattar, Rejane; Silva, Fernando Marcuz; Alexandrino, Ana Maria; Laudanna, Antonio Atilio [Sao Paulo Univ., SP (Brazil). Hospital das Clinicas. Dept. de Gastroenterologia]. E-mail: shiroineko@uol.com.br

    1999-02-01

    The aim of this study was to validate the {sup 14} C-urea breath test for use in diagnosis of Helicobacter pylori infection. Thirty H. pylori positive patients, based on histologic test and thirty H. pylori negative patients by histology and anti-H pylori IgG entered the study. Fasting patients drank 5 uCi of {sup 14} C-urea in 20 ml of water. Breath samples were collected at O, 5, 10, 15, 20 and 30 min. The difference of cpm values between the two groups was significant at all the time intervals, besides time 0 (p < 0.0001). At 20 min, the test gave 100% sensitivity and specificity with a cut-off value of 562 cpm. Females were higher expirers than males (p=0.005). {sup 14} C-urea breath test is highly accurate for Helicobacter pylori diagnosis. It is fast, simple and should be the non-invasive test used after treating Helicobacter pylori infection. (author)

  20. A procedure for batch separation of 14C-hexose from 14C-sucrose

    International Nuclear Information System (INIS)

    Tarpley, L.; Vietor, D.M.

    1991-01-01

    This presentation describes a method for separating 14 C-hexose from 14 C-sucrose in extracts of plant tissue. Portions of ethanol extracts are treated with activated charcoal in microcentrifuge tubes. Aliquots are removed, ethanol evaporated and replaced with reaction mixture that phosphorylates hexose (HEPPS, K 2 HPO 4 , Mg(C 2 H 3 O 2 ) 2 , ovalbumen, Na 2 ATP, yeast hexokinase). After a time course, the hexokinase reaction is stopped (slowed considerably) to minimize effects of contamination enzyme activities. The stopping agent used is lyxose, a nonphosphorylable analogue of glucose. The strong anionic charge of phosphate introduced through the hexokinase action results in binding (> 95%) of hexose-phosphate to anion-exchange resin. Sucrose remains unbound (> 95%) in solution. This batch ion-exchange is performed in microcentrifuge tubes to allow many samples to be processed simultaneously. Recovery of radiolabel in extracts is complete (99%), and determinations are repeatable (cv = 23%). This method for routinely separating and quantifying 14 C-hexose and 14 C-sucrose in plant tissue extracts can contribute to the economy and feasibility of studies of 14 C-photoassimilate partitioning to soluble sugars within and among plant tissues

  1. Dating of groundwater with tritium and 14C

    International Nuclear Information System (INIS)

    Muennich, K.O.; Roether, W.; Thilo, L.

    1967-01-01

    Shallow groundwater can be dated with some accuracy on the basis of its bomb tritium content if the unsaturated soil cover and the aquifer itself is sufficiently homogeneous. A few examples from the Rhine valley are presented. The decrease in tritium level from the water table to a few metres below is nearly two orders of magnitude. Agreement between the measured or estimated variation of bomb tritium in rain during the past decade and the tritium found in shallow groundwater can be obtained if one takes into account that (a) practically no summer rain reaches the water table, and (b) water is mixed by diffusion. Both effects can also be observed in the soil moisture of the unsaturated soil above the water table. Carbon-14 increase in groundwater due to bombs is delayed compared to tritium, the reasons being delay in the biological system and exchange with the carbonate in the soil. Nevertheless lysimeters show a marked increase of 14 C, which depends on the plant cover, being high in a plant-covered lysimeter and low in a bare one. A simple model is presented, which allows the evaluation of the influence of exchange on the 14 C age obtained. It turns out that the deviation from the true age depends on the ratio of the carbonate content in the aquifer material to the carbonate content of the water, on the specific contact surface or the grain size but not on the groundwater velocity. On the basis of this model the experimental finding that 14 C ages are usually in agreement with other age estimates despite the loss by exchange is plausible owing to the fact that only material of sufficiently coarse grain size can make up a reasonable aquifer. Assuming only exchange with a monomolecular surface layer of the carbonate grains one finds that the 14 C age is likely to differ by not more than a factor of two in the most unfavourable case. Under natural conditions (steady state of cosmic-ray-produced 14 C) the 14 C content of shallow groundwater is hardly influenced at

  2. Biokinetics and radiation dosimetry of {sup 14}C-labelled triolein, urea, glycocholic acid and xylose in man. Studies related to nuclear medicine 'breath tests' using accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsson, Mikael

    2002-08-01

    {sup 14}C-labelled substances have been used in biomedical research and clinical medicine for over 50 years. Physicians and scientists however, often hesitate to use these substances in patients and volunteers because the radiation dosimetry is unclear. In this work detailed long-term biokinetic and dosimetric estimation have been carried out for four clinically used {sup 14}C-breath tests: {sup 14}C-triolein (examination of fat malabsorption), urea (detection of Helicobacter pylori infection in the stomach), glycocholic acid and xylose (examination of bacterial overgrowth in the small intestine) by using the highly sensitive accelerator mass-spectrometry (AMS) technique. The AMS technique has been used to measure low {sup 14}C concentrations in small samples of exhaled air, urine, faeces and tissue samples and has improved the base for the estimation of the absorbed dose to various organs and tissues and the effective dose to man. The high sensitivity of the AMS system has also made it possible to perform {sup 14}C breath tests on patient groups which were earlier subject for restriction (e.g. small children). In summary, our results show that for adult patients - and in the case of {sup 14}C-urea breath test also for children down to 3 years of age - the dose contributions are comparatively low, both described as organ doses and as effective doses. For adults, the latter is: {sup 14}C-glycocholic acid - 0.4 mSv/MBq, {sup 14}C-triolein - 0.3 mSv/MBq, {sup 14}C-xylose - 0.1 mSv/MBq and {sup 14}C-urea - 0.04 mSv/MBq. Thus, from a radiation protection point of view there is no reason for restrictions in using any of the {sup 14}C-labelled radiopharmaceutical included in this work in the activities normally used (0.07-0.2 MBq for a 70 kg patient)

  3. Atmospheric 14C variations derived from tree rings during the early Younger Dryas

    Science.gov (United States)

    Hua, Quan; Barbetti, Mike; Fink, David; Kaiser, Klaus Felix; Friedrich, Michael; Kromer, Bernd; Levchenko, Vladimir A.; Zoppi, Ugo; Smith, Andrew M.; Bertuch, Fiona

    2009-12-01

    Atmospheric radiocarbon variations over the Younger Dryas interval, from ˜13,000 to 11,600 cal yr BP, are of immense scientific interest because they reveal crucial information about the linkages between climate, ocean circulation and the carbon cycle. However, no direct and reliable atmospheric 14C records based on tree rings for the entire Younger Dryas have been available. In this paper, we present (1) high-precision 14C measurements on the extension of absolute tree-ring chronology from 12,400 to 12,560 cal yr BP and (2) high-precision, high-resolution atmospheric 14C record derived from a 617-yr-long tree-ring chronology of Huon pine from Tasmania, Australia, spanning the early Younger Dryas. The new tree-ring 14C records bridge the current gap in European tree-ring radiocarbon chronologies during the early Younger Dryas, linking the floating Lateglacial Pine record to the absolute tree-ring timescale. A continuous and reliable atmospheric 14C record for the past 14,000 cal yr BP including the Younger Dryas is now available. The new records indicate that the abrupt rise in atmospheric Δ 14C associated with the Younger Dryas onset occurs at ˜12,760 cal yr BP, ˜240 yrs later than that recorded in Cariaco varves, with a smaller magnitude of ˜40‰ followed by several centennial Δ 14C variations of 20-25‰. Comparing the tree-ring Δ 14C to marine-derived Δ 14C and modelled Δ 14C based on ice-core 10Be fluxes, we conclude that changes in ocean circulation were mainly responsible for the Younger Dryas onset, while a combination of changes in ocean circulation and 14C production rate were responsible for atmospheric Δ 14C variations for the remainder of the Younger Dryas.

  4. Feasibility studies of RFQ based 14C accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Guo Zhiyu; Liu Kexin; Yan Xueqing; Xie Yi; Fang Jiaxun; Chen Jiaer

    2007-01-01

    Electrostatic accelerators with terminal voltage less than 1 MeV have been successfully used for 14 C AMS. This contribution shows that a small RFQ accelerator may also be suitable for AMS 14 C measurements. A well-designed RFQ accelerator can realize a low energy spread and high isotopic selection with a length of less than 1 m and reasonable power consumption. Compared with small tandem accelerators, a RFQ does not need isolation gas and can accept much higher beam currents. Its stripper would be at ground potential and there would be no further acceleration after stripping, so the background from charge exchange processes should be lower. The RFQ design and system are described

  5. Effect of level of dietary protein on the distribution of 14C-activity from exogenous 14C-inosine in chicks

    International Nuclear Information System (INIS)

    Masushige, Shoichi; Tadokoro, Tadahiro; Suzuki, Takao; Nakajima, Hisao.

    1983-01-01

    The effect of dietary protein level on the metabolic fate of intraperitoneally administered (exogeneous) 8- 14 C-inosine in chicks was studied. Three different protein level diets (low, standard and high) were prepared. Chicks were fed on these diets for 10 days, respectively and the following results were found: (1) RNA content of liver, small intestine and muscle in chicks fed on a low protein diet was decreased as compared to other diet groups, but no difference was observed in kidney or pancreas. (2) 14 C uptake by organs from exogeneous 8- 14 C-inosine was determined. The uptake of 14 C in kidney, pancreas and small intestine was higher than that in liver and muscle. Moreover, the uptake by tissues in the low protein groups was significantly higher than that in either the standard or high protein groups, but no difference was observed between these latter two groups. (3) The rate of incorporation of 14 C labelled purine by acid soluble materials and RNA was higher in kidney, pancreas and small intestine than in liver and muscle, and also higher in chicks fed on a low protein diet than in either the standard or high protein groups. (4) It was revealed that the 14 C-labelled purine rings from 8- 14 C-inosine were incorporated into AMP and GMP as constituents of RNA. (author)

  6. Simultaneous measurement of cholesterol 7 alpha-hydroxylase activity by reverse-phase high-performance liquid chromatography using both endogenous and exogenous [4-14C]cholesterol as substrate

    International Nuclear Information System (INIS)

    Hylemon, P.B.; Studer, E.J.; Pandak, W.M.; Heuman, D.M.; Vlahcevic, Z.R.; Chiang, J.Y.

    1989-01-01

    The HPLC-spectrophotometric method for measuring cholesterol 7 alpha-hydroxylase activity was modified by using a C-18 reverse-phase column to separate 7 alpha-hydroxy-4-cholesten-3-one and 4-cholesten-3-one and by adding 7 beta-hydroxycholesterol to each reaction mixture as an internal recovery standard. With this method, we were able to simultaneously measure cholesterol 7 alpha-hydroxylase activity using endogenous cholesterol and exogenous [4- 14 C]cholesterol as substrate. Rat liver cytosol differentially stimulated (286%) the 7 alpha-hydroxylation of exogenous [4- 14 C]-cholesterol. In contrast, total cholesterol 7 alpha-hydroxylase activity was stimulated only 35% by cytosol. This method should prove useful for studying mechanisms of cholesterol delivery to cholesterol 7 alpha-hydroxylase

  7. Residues of 14C-paclobutrazol in mangoes

    International Nuclear Information System (INIS)

    Costa, Maria A.; Tornisielo, Valdemar L.; Castanho, Giuliane M.

    2009-01-01

    Paclobutrazol (PBZ) is a growth regulator used in agricultural systems whose purpose is the control of vegetative growth, stimulating the reproductive capacity of plants. This growth regulator remains active in soil for a long time and its half-life varies with the type of soil and climatic conditions, can severely affect the development of crops. This work aimed to study the residues / metabolites of 14 C-PBZ in mango pulp Tommy Atkins. The tests were performed with mangoes grown in pots stainless steel and application of 14 C-PBZ was performed by the soil projection of the crown, and the mangoes tested in two periods, one year and two years after application. To evaluate the levels of residues of 14 C-PBZ was realize the burning of 200 mg of pulp on biological oxidized and detached 14 CO 2 was detected by liquid scintillation spectrophotometer. The results were 1.65 % of residue of PBZ on fruit collected after two years of application and 4.30 % of residue of PBZ collected on fruit after a year of application and also can see that the product remained in the soil for more than one year, is translocated to the plant and reach the edible part, the pulp fruit. The identification of residual 14 C- PBZ/metabolites by thin-layer chromatography did not reveal any pattern of PBZ / metabolites due to the low activity detected in the samples. Therefore, another procedure was performed for extraction and then analyzed by high performance liquid chromatography (HPLC) for detection of metabolites in the PBZ of mango pulp. (author)

  8. May {sup 14}C be used to date contemporary art?

    Energy Technology Data Exchange (ETDEWEB)

    Fedi, M.E., E-mail: fedi@fi.infn.it [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Caforio, L. [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Fisica, Universita di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Mando, P.A. [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Fisica e Astronomia, Universita di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy); Petrucci, F. [Dipartimento di Fisica, Universita di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); INFN Sezione di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Taccetti, F. [INFN Sezione di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Italy)

    2013-01-15

    The use of radiocarbon in forensics is by now widespread, thanks to the so-called bomb peak, which makes it possible to perform high-precision dating. Since 1955, {sup 14}C concentration in the atmosphere had strongly increased due to nuclear explosions, reaching its maximum value in 1963-1965. After the Nuclear Test Ban Treaty, {sup 14}C started to decrease as a consequence of the exchanges between atmosphere and the other natural carbon reservoirs. Nowadays, it is still slightly above the pre-bomb value. The work presented in this paper is based on the idea of exploiting the bomb peak to 'precisely' date works of contemporary art, with the aim at identifying possible fakes. We analysed two kinds of materials from the 20th century: newspapers and painting canvases. Newspaper samples were taken because they might in principle be considered to represent dated samples (considering the date on the issues). Our data (28 samples) show a trend similar to atmospheric data in the literature, although with some differences; the paper peak is flatter and shifted towards more recent years (about five years) with respect to the atmospheric data. This can be explained by taking paper manufacturing processes into account. As to the canvas samples, the measured {sup 14}C concentrations were generally reasonably consistent with the expected concentrations (based on the year on the paintings). However, this does not indicate that the interpretation of the results is simpler and more straightforward. Obviously, we only measure the {sup 14}C concentration of the fibre used for the canvas, which does not necessarily measure the date the painting was manufactured. In this paper, sample preparation and experimental results will be discussed, in order to show the potential as well as the limitations of radiocarbon to date contemporary art.

  9. May 14C be used to date contemporary art?

    International Nuclear Information System (INIS)

    Fedi, M.E.; Caforio, L.; Mandò, P.A.; Petrucci, F.; Taccetti, F.

    2013-01-01

    The use of radiocarbon in forensics is by now widespread, thanks to the so-called bomb peak, which makes it possible to perform high-precision dating. Since 1955, 14 C concentration in the atmosphere had strongly increased due to nuclear explosions, reaching its maximum value in 1963–1965. After the Nuclear Test Ban Treaty, 14 C started to decrease as a consequence of the exchanges between atmosphere and the other natural carbon reservoirs. Nowadays, it is still slightly above the pre-bomb value. The work presented in this paper is based on the idea of exploiting the bomb peak to “precisely” date works of contemporary art, with the aim at identifying possible fakes. We analysed two kinds of materials from the 20th century: newspapers and painting canvases. Newspaper samples were taken because they might in principle be considered to represent dated samples (considering the date on the issues). Our data (28 samples) show a trend similar to atmospheric data in the literature, although with some differences; the paper peak is flatter and shifted towards more recent years (about five years) with respect to the atmospheric data. This can be explained by taking paper manufacturing processes into account. As to the canvas samples, the measured 14 C concentrations were generally reasonably consistent with the expected concentrations (based on the year on the paintings). However, this does not indicate that the interpretation of the results is simpler and more straightforward. Obviously, we only measure the 14 C concentration of the fibre used for the canvas, which does not necessarily measure the date the painting was manufactured. In this paper, sample preparation and experimental results will be discussed, in order to show the potential as well as the limitations of radiocarbon to date contemporary art.

  10. Residues of {sup 14}C-paclobutrazol in mangoes

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Maria A.; Tornisielo, Valdemar L.; Castanho, Giuliane M., E-mail: macosta@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Ecotoxicologia

    2009-07-01

    Paclobutrazol (PBZ) is a growth regulator used in agricultural systems whose purpose is the control of vegetative growth, stimulating the reproductive capacity of plants. This growth regulator remains active in soil for a long time and its half-life varies with the type of soil and climatic conditions, can severely affect the development of crops. This work aimed to study the residues / metabolites of {sup 14}C-PBZ in mango pulp Tommy Atkins. The tests were performed with mangoes grown in pots stainless steel and application of {sup 14}C-PBZ was performed by the soil projection of the crown, and the mangoes tested in two periods, one year and two years after application. To evaluate the levels of residues of {sup 14}C-PBZ was realize the burning of 200 mg of pulp on biological oxidized and detached {sup 14}CO{sub 2} was detected by liquid scintillation spectrophotometer. The results were 1.65 % of residue of PBZ on fruit collected after two years of application and 4.30 % of residue of PBZ collected on fruit after a year of application and also can see that the product remained in the soil for more than one year, is translocated to the plant and reach the edible part, the pulp fruit. The identification of residual {sup 14}C- PBZ/metabolites by thin-layer chromatography did not reveal any pattern of PBZ / metabolites due to the low activity detected in the samples. Therefore, another procedure was performed for extraction and then analyzed by high performance liquid chromatography (HPLC) for detection of metabolites in the PBZ of mango pulp. (author)

  11. {sup 14}C content in aerosols in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, V.; Solís, C.; Chávez, E.; Andrade, E.; Ortiz, M.E.; Huerta, A.; Aragón, J.; Rodríguez-Ceja, M. [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, México, D.F. 01000 (Mexico); Martínez, M.A. [Facultad de Ciencias, Universidad Nacional Autónoma de México (Mexico); Ortiz, E. [Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo 180, C. P. 02200 México, D.F. (Mexico)

    2016-03-15

    {sup 14}C-AMS of total carbon was determined in aerosols (PM{sub 10} fraction), collected in Mexico City during two weeks from 21 November to 3 December 2012. Other tracers such as total carbon (TC), organic carbon (OC), elemental carbon (EC) and trace element contents were also determined. F{sup 14}C values varied from 0.39 to 0.48 with an average of 0.43. These values are slightly lower than those previously obtained for PM{sub 2.5} in 2003 and 2006 and reflect a high contribution of fossil CO{sub 2} to the carbonaceous matter in aerosols from Mexico City. In contrast, from 2006 to 2012 PM{sub 10} increased; EC, Ca, Ti and Fe concentrations remained constant, while OC, TC and K concentrations decreased. The use of potassium as an indicator of biomass burning showed that this source was negligible during this campaign. Combined analytical approaches allowed us to distinguish temporal variations of anthropogenic and natural inputs to the F{sup 14}C.

  12. Behaviour of 14C-DDT in Sudan Gezira soil

    International Nuclear Information System (INIS)

    Abdalla, A.M.; El-Zorgani, G.A.

    1988-01-01

    Field cylinders as described in the model experiment for determination of 14 C-DDT in Sudan Gezira soil were prepared and samples were collected for determination of 14 C-activity at various intervals. About 83-87% of the applied radioactivity was recovered in the extracts from the top 10 cm layer of soil. The loss rate of the chemical from soil increased with time apparently by volatilization and thermal degradation due to high soil temperature, intensive solar radiation and low soil organic matter. This resulted in a half-life of approx. 5 weeks. The major part of the chemical and possible metabolites were detected in the top 10 cm layer. Approximately 8-10% of the applied 14 C was detected in samples collected after 16-20 weeks. TLC and autoradiography indicated the presence of p,p'-DDT and p,p'-DDE as the major metabolite. Also traces of TDE were detected in some samples. These results showed that under Sudanese tropical conditions, DDT dissipates very rapidly in soils compared to dissipation in temperate regions. (author). 6 refs, 2 tabs

  13. METABOLISM OF [14C]GA19 AND [14C]GA53 BY ECOTYPES OF ...

    African Journals Online (AJOL)

    ADMIN

    hand, metabolism of [14C]GA53 was very limited in all day-length treatments and during both, day and night periods. ... compounds which are formed by covalent coupling of GAs to .... For each ecotype day-time and night-time metabolism of ...

  14. Synthesis of [methyl-14C]crotonobetaine from DL-[methyl-14C]carnitine

    International Nuclear Information System (INIS)

    Loester, H.; Seim, H.

    1996-01-01

    The causes of carnitine deficiency syndromes are not completely understood, but decomposition of L-carnitine in vivo is likely to be involved. Carnitine is metabolized to γ-butyrobetaine, and crotonobetaine is probably an intermediate in this pathway. To validate experimentally the precursor-product relationship between the three physiologically occuring γ-betaines - L-carnitine, crotonobetaine, γ-butyrobetaine - labelling with stable or radioactive isotopes became necessary. Methyl-labelled carnitine isomers (L(-)-, D(+)- or DL-) or γ-butyrobetaine can be easily synthesized by methylation of 4-amino-3-hydroxybutyric acid isomers or 4-aminobutyric acid, respectively. Because of problems with the 4-aminocrotonic acid, we synthesized labelled crotonbetaine from labelled carnitine. Thus, DL-[methyl- 14 C]carnitine was dehydrated by reaction with concentrated sulfuric acid. After removal of the latter the products were separated and purified by ion exchange chromatography on DOWEX 50 WX8 (200 - 400 mesh) and gradient elution with hydrochloric acid. In addition to the labelled main product [methyl- 14 C]crotonobetaine (yield about 50 %), [methyl- 14 C]glycine betaine and [methyl- 14 C]acetonyl-trimethylammonium (ATMA) were formed. The end products were identified by combined thin layer chromatography/autoradiography and quantified by liquid scintillation counting. (Author)

  15. Synthesis of ethanol {sup 14}C-1; Synthese d'ethanol {sup 14}C-1

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, R E; Pichat, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The direct reduction by LiAlH{sub 4}, of a suspension of anhydrous sodium acetate in tetra-hydro-furfuryl-oxy-tetra-hydro-pyran is described. This study has shown that the ethanol thus obtained is impure and that the yields are erratic. On the contrary the reduction of acetyl chloride 1-{sup 14}C by LiAlH{sub 4}, in 'diethyl carbitol' leads to ethanol 1-{sup 14}C of satisfactory purity with a yield of about 71 percent. (author) [French] Une etude de la reduction directe par LiAlH{sub 4}, de l'acetate de soude anhydre en suspension dans le tetrahydrofurfuryloxytetrahydropyrane est decrite. Cette etude a montre que l'on obtient de l'ethanol souille d'impuretes, avec un rendement variable. Par contre, la reduction du chlorure d'acetyle {sup 14}C-1 par LiAlH{sub 4}, dans le 'diethyl carbitol' conduit a l'ethanol {sup 14}C-1 de purete convenable avec un rendement de l'ordre de 71 pour cent. (auteur)

  16. A critical review of atmospheric 14 C activities

    International Nuclear Information System (INIS)

    Krajcar Bronic, I.; Horvatincic, N.; Baresic, J.; Obelic, B.; Vreca, P.

    2006-01-01

    14 C activity of atmospheric CO 2 has been measured at the Rudjer Boskovi Institute as a part of environmental monitoring in order to determine possible differences between clean-air sites, industrialized city and sites in the vicinity of nuclear power plant. Samples of CO 2 from the atmosphere have been collected by absorption of CO 2 on the saturated carbonate-free NaOH solution for a period of 1 month under stationary conditions. The obtained Na 2 CO 3 has been dissolved in HCl and the produced CO 2 used for CH 4 preparation by catalytic reaction with H 2 at 450 degrees Celsius. A gas proportional counter filled with CH 4 has been used for 14 C activity measurement. The method of collection of CO 2 does not require any power source and can be therefore used for sampling at the remote sites, such as mountains or forests. However,due to the lack of mixing of the Na OH solution, the absorption process is limited on the surface of the solution, and there exists the possibility of fractionation of carbon isotopes due to different reaction rate constants of 12 C and 13 C. A continuous record of atmospheric 14 CO 2 activity exists for the city of Zagreb (1986 to 2005), while shorter records (1-2 years) exist for several other sites of various characteristics: two clean-air sites (Mt. Medvednica, altitude about 1000 m a.s.l., for period 1995 to 1996, and the Plitvice National Park for period 2003 to 2005), and a site close to the Nuclear Power Plant Krsko (1984 to 1986).Within the bilateral Croatian-Slovene project we have recently measured also the stable isotope composition (δ13 C) of Na 2 CO 3 collected at two different sampling sites in order to determine seasonal fluctuations in both 14 C and 13 C isotope composition. Unexpectedly low δ13 C values have been obtained about (-25±2)0/00 instead of expected (-7±1)0/00. Such low values have been attributed to the carbon isotope fractionation during the CO 2 absorption on the highly alkaline medium because of

  17. 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)

  18. 14C-urea breath test for the detection of Helicobacter pylori

    NARCIS (Netherlands)

    Veldhuyzen van Zanten, S. J.; Tytgat, K. M.; Hollingsworth, J.; Jalali, S.; Rshid, F. A.; Bowen, B. M.; Goldie, J.; Goodacre, R. L.; Riddell, R. H.; Hunt, R. H.

    1990-01-01

    The high urease activity of Helicobacter pylori can be used to detect this bacterium by noninvasive breath tests. We have developed a 14C-urea breath test which uses 5 microCi 14C with 50 mg nonradioactive urea. Breath samples are collected at baseline and every 30 min for 2 h. Our study compared

  19. /sup 14/C uncovers the past

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Radiocarbon dating, a method of dating prehistoric remains that has been developed since the Second World War, is based on the fact that all organic matter contains a radioactive isotope of carbon -/sup 14/C- which, because it decays at a fixed rate, gives a good indication of the age of the substance. The CSIR's National Physical Research Laboratory entered the field of radio-carbon dating in 1967, when the Nature Isotopes Division was established. The division has become a world center of excellence and much has been done to clear up the chronology of southern African prehistory. It has been found, for instance, that anatomically modern man appeared in southern Africa some 40000 years earlier than in Europe, and that the Zimbabwe ruins were built mainly around the year 1350 AD. The radio-carbon method can also be used to determine the age and flow rate of underground water and the rate at which tracer gases dissolve in the oceans, i.e. the efficiency with which the oceans cleanse the atmosphere from pollutants.

  20. Convenient synthesis of [2-{sup 14}C]-methylglyoxal bis(guanylhydrazone), [{sup 14}C]-mitoguazone

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, A.; Ellames, G.J. [Sterling Winthrop Research Centre, Alnwick (United Kingdom). Pharmaceuticals Research Div.

    1995-01-01

    [2-{sup 14}C]-Methylglyoxal bis(guanylhydrazone) dihydrochloride, [{sup 14}C]-mitoguazone has been prepared in three steps from potassium[1-{sup 14}C]-acetate in an overall radiochemical yield of 16%. The key steps in this procedure are the formation of the sodium salt of[acetone-2-{sup 14}C]-methylsulfinylacetone, and Pummerer rearrangement to the [{sup 14}C] labelled hermithioacetal, which is trapped with two equivalents of aminoguanidine to afford the desired [{sup 14}C]-mitoguazone. (Author).

  1. Rarotonga Radiocarbon (delta 14C) for 1950 to 1997

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Rarotonga coral radiocarbon (14C) timeseries. Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4 per mil as documented by an...

  2. 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

  3. Translocation and distribution of 14C-assimilation products in soybeans with different growth property

    International Nuclear Information System (INIS)

    Yoshida, Koichi; Gotoh, Kanji

    1975-01-01

    To 3 different kinds of soybeans, Tokachinagaha (Determinate), Koganejiro (Intermediate), and Harosoy (Indeterminate), 14 C was given at 3 stages of growth, namely, initial flowering, young pod development, and seed fattening periods. The 14 C assimilation efficiency, namely, the value of total 14 C assimilated divided by the area of the leaves which assimilated 14 C, was large when the leaf area was small. The value decreased with the increase of the leaf area. The rate of translocation of 14 C assimilation products was 20-50% in the period of initial flowering. The rate was highest in Tokachinagaha, followed by Koganejiro and Harosoy in this order. The difference was small in the period of young pod development. In the period of initial flowering, the distribution of 14 C to lower leaves and branches was high in Harosoy. In the period of young pod development, 30-40% of the assimilated 14 C was found in stems. This distribution is possibly due to temporary storage. In the period of seed fattening, 80-90% of the assimilated 14 C was present in pods and seeds. It was then concluded that the movement of assimilated products is high in the determinate type in the initial growth period. In the seed fattening period, the rate is high in the indeterminate type soy beans. (Fukutomi, T.)

  4. Disposition of 14C-β-carotene following delivery with autologous triacylglyceride-rich lipoproteins

    International Nuclear Information System (INIS)

    Dueker, Stephen R.; Le Thuy Vuong; Faulkner, Brian; Buchholz, Bruce A.; Vogel, John S.

    2007-01-01

    Following ingestion, a fraction of β-carotene is cleaved into vitamin A in the intestine, while another is absorbed intact and distributed among tissues and organs. The extent to which this absorbed β-carotene serves as a source of vitamin A is unknown in vivo. In the present study we use the attomole sensitivity of accelerator mass spectrometry (AMS) for 14 C to quantify the disposition of 14 C-β-carotene (930 ng; 60.4 nCi of activity) after intravenous injection with an autologous triacylglyceride-rich lipoprotein fraction in a single volunteer. Total 14 C was quantified in serial plasma samples and also in triglyceride-rich, and low density lipoprotein, subfractions. The appearance of 14 C-retinol, the circulating form of vitamin A in plasma, was determined by chromatographic separation of plasma retinol extracts prior to AMS analysis. The data showed that 14 C concentrations rapidly decayed within the triglyceride-rich lipoprotein fractions after injection, whereas low density lipoprotein 14 C began a significant rise in 14 C 5 h post dose. Plasma 14 C-retinol also appeared at 5 h post dose and its concentrations were maintained above baseline for >88 days. Based upon comparisons of 14 C-retinol concentrations following an earlier study with orally dosed 14 C-β-carotene, a molar vitamin A value of the absorbed β-carotene of 0.19 was derived, meaning that 1 mole of absorbed β-carotene provides 0.19 moles of vitamin A. This is the first study to show that infused β-carotene contributes to the vitamin A economy in humans in vivo

  5. S-adenosyl-L-(l-14C)-homocysteine

    International Nuclear Information System (INIS)

    Thomas, H.J.; Montgomery, J.A.

    1987-01-01

    S-Adenosyl-L-(1- 14 C)-homocysteine was prepared from commercially available L-(1- 14 C)-methionine by conversion first to S-benzyl-L-(1- 14 C)-homocysteine which upon treatment with sodium in liquid ammonia gave the disodium salt of L-(1- 14 C)-homocysteine. Reaction of this sodium salt with 5'-O-tosyladenosine gave the title compound. (author)

  6. 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

  7. {sup 14}C AMS dating Yongcheon cave

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.H., E-mail: jefflee@snu.ac.kr [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Choe, K. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, J.C. [Dept. of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Choi, S.H.; Kang, J.; Song, S.; Song, Y.M. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Jang, J.G. [Jeju National Museum, Jeju 690-782 (Korea, Republic of)

    2013-01-15

    The biggest island in South Korea is Jeju Island, which lies 80 km south of the mainland and has one shield volcano, Mt. Halla. The volcanic island and its lava tubes were added to the world heritage list by UNESCO in 2007. Among the many lava tubes on the island, a unique cave had been accidentally found in 2005 while some workers were replacing a telephone pole. Until the discovery, it had been completely isolated from the outside by naturally-built sand blocks. Yongcheon cave is a lime-decorated lava tube showing both the properties of a volcanic lava tube and a limestone cave. This cave, about 3 km in length, is acknowledged to be the best of this type in the world and includes a large clean-water lake, lava falls, and richly developed speleothems inside it. Even though there is archaeological evidence from well preserved pottery that ancient people entered this place, the preservation of artifacts was ensured by a geological change that made later entrance difficult. We have collected charcoal samples scattered around the cave and dated them using AMS. Ages were in the range of ca. 1570-1260 BP (A.D. 340-880) and this corresponds to the Ancient Three Kingdoms and the Unified Silla era in Korean history. The {sup 14}C AMS measurement results presented in this paper on wood charcoal provide precise dates which will be very useful not only to clarify the nature of human activities in this cave but also to provide reference dates when comparing other dating methods.

  8. 14C AMS dating Yongcheon cave

    International Nuclear Information System (INIS)

    Lee, J.H.; Choe, K.; Kim, J.C.; Choi, S.H.; Kang, J.; Song, S.; Song, Y.M.; Jang, J.G.

    2013-01-01

    The biggest island in South Korea is Jeju Island, which lies 80 km south of the mainland and has one shield volcano, Mt. Halla. The volcanic island and its lava tubes were added to the world heritage list by UNESCO in 2007. Among the many lava tubes on the island, a unique cave had been accidentally found in 2005 while some workers were replacing a telephone pole. Until the discovery, it had been completely isolated from the outside by naturally-built sand blocks. Yongcheon cave is a lime-decorated lava tube showing both the properties of a volcanic lava tube and a limestone cave. This cave, about 3 km in length, is acknowledged to be the best of this type in the world and includes a large clean-water lake, lava falls, and richly developed speleothems inside it. Even though there is archaeological evidence from well preserved pottery that ancient people entered this place, the preservation of artifacts was ensured by a geological change that made later entrance difficult. We have collected charcoal samples scattered around the cave and dated them using AMS. Ages were in the range of ca. 1570-1260 BP (A.D. 340–880) and this corresponds to the Ancient Three Kingdoms and the Unified Silla era in Korean history. The 14 C AMS measurement results presented in this paper on wood charcoal provide precise dates which will be very useful not only to clarify the nature of human activities in this cave but also to provide reference dates when comparing other dating methods.

  9. How reliable are the sup 14 C-urea breath test and specific serology for the detection of gastric campylobacter

    Energy Technology Data Exchange (ETDEWEB)

    Husebye, E; O' Leary, D; Skar, V; Melby, K [Ullevaal Sykehus, Oslo (Norway)

    1990-01-01

    Detection of gastric campylobacter by the {sup 14}C-urea breath test and serology were correlated to biopsy culture in 25 unselected outpatients referred for gastroscopy. All the 17 culture-positive patients had positive {sup 14}C-urea breath test, and 16 had positive serology. Of eight culture-negative patients, six patients had negative breath test and seven negative serology. A high degree of reproducibility was found when two subsequent breath tests were performed in 11 healthy volunteers. The breath test values obtained at 10 min showed a strong correlation to the accumulated values within 30 min. Breath sampling once, 10 min after intake of 2.5 {mu}Ci {sup 14}C-urea, seems sufficient for the detection of gastric campylobacter. The {sup 14}C-urea breath test correlates well with biopsy culture and provides a sensitive tool for the detection of gastric campylobacter. Serology also corresponds well with biopsy culture and should provide a useful tool for epidemiologic studies. 22 refs., 4 figs., 1 tab.

  10. Novel double-isotope technique for enzymatic assay of catecholamines, permitting high precision, sensitivity and plasma sample capacity

    International Nuclear Information System (INIS)

    Brown, M.J.; Jenner, D.A.

    1981-01-01

    A novel use of a double-isotope method is described which allows radioenzymatic assays to combine precision and sensitivity. In the catechol O-methyltransferase assay separate portions of each plasma sample are incubated with either S-[ 3 H]- or S-[ 14 C]-adenosyl-L-methionine. Standards of noradrenaline and adrenaline are added to the latter portions and are thus converted into standards of [ 14 C]metadrenalines. These are added to the 3 H-labelled portions after the incubation, where they function as tracers. The final recovery of 14 C radioactivity corrects for (a) the efficiency of methylation in the plasma sample concerned and (b) the recovery of metadrenalines during the extraction procedures. The 3 H/ 14 C ratio is constant in each assay for a given catecholamine concentration and is determined for samples to which standards of noradrenaline and adrenaline are added to the 3 H- (as well as the 14 C-) labelled portions before the initial incubation. The sensitivity of the assay is increased by using high specific radioactivity S-[ 3 H]adenosyl-L-methionine, and low backgrounds are maintained by catecholamine depletion in vivo in the rats used for enzyme preparation. Both catecholamines (1.5 pg/ml; 10 pmol/l) may be detected; the coefficients of variation are 3.0 and 3.2% for noradrenaline and adrenaline respectively (intra-assay) and 4.6 and 5.0% (inter-assay). (author)

  11. Autoradiographic disposition of [1-methyl-14C]- and [2-14C]caffeine in mice

    International Nuclear Information System (INIS)

    Lachance, M.P.; Marlowe, C.; Waddell, W.J.

    1983-01-01

    Male, C57B1/6J mice received either [1-methyl-14C]caffeine or [2-14C]caffeine via the tail vein at a dose of 0.7 or 11 mg/kg, respectively. At 0.1, 0.33, 1, 3, 9, and 24 hr after treatment, the mice were anesthetized with ether and frozen by immersion in dry ice/hexane. The mice were processed for whole-body autoradiography by the Ullberg technique; this procedure does not allow thawing or contact with solvents. All autoradiographs revealed some retention of radioactivity at early time intervals in the lacrimal glands, seminal vesicle fluid, nasal and olfactory epithelium, and retinal melanocytes. The remaining portion of the animal was densitometrically uniform except for the lower levels noted in the CNS and adipose tissues. Excretion of radioactivity by the liver and kidneys seems to be the major routes of elimination. Localization in the liver at late time intervals was confined principally to the centrilobular region. Late sites of retention, observed only after [1-methyl-14C]caffeine administration, included the pancreas, minor and major salivary glands, splenic red pulp, thymal cortex, bone marrow, and gastrointestinal epithelium. Sites of localization present in both studies included the olfactory epithelium, lacrimal glands, hair follicles, and retinal melanocytes. Further studies are needed to determine whether the localization at these various sites is due to metabolic degradation, active transport, or possibly a specific receptor interaction

  12. Synthesis of /sup 14/C-labelled butoxyethoxyethanol

    Energy Technology Data Exchange (ETDEWEB)

    Thijssen, J.B.A.; Janssen, C.G.M.; Verluyten, W.L.M.; Heykants, J.J.P.

    1986-02-01

    Butoxyethoxyethanol, an organic solvent used as carrier in the levamisole pour-on formulation, was synthesized via a Makosza etherification of 1-/sup 14/C-labelled bromobutane with mono tetrahydropyranyl (T.H.P.) protected diethylene glycol and subsequent removal of the T.H.P. protecting group. The compounds' synthetic yield was 88.8%; it had a specific activity of 32.5 mCi/mmol. The reaction product was radiochemically pure (99.6%) according to high-performance liquid chromatography and thin-layer chromatography in three solvent systems.

  13. {8-14C}-Adenine and {1-14C}-isopentenyl pyrophosphate - precursors for root-produced cytokinins in the tomato (Lycopersicon esculentum mill.)

    International Nuclear Information System (INIS)

    Dickinson, J.R.

    1985-01-01

    Following the detection of reasonable levels of biologically active cytokinin-like compounds in one-month-old tomato plants, the possible involvement of {8- 14 C}-adenine and {1- 14 C}-isopentenyl pyrophosphate in the biosynthetic pathway leading to an accumulation of free zeatin derivatives, was studied. Intact tomato plants were used for a time-course study involving the uptake of {8- 14 C}-adenine and the tentative identification of compounds into which the 14 C became incorporated. Using high performance liquid chromatography, radioactive trans-zeatin was identified as being present in the Dowex 50 root extract. The 12-hour time interval was used and the roots of the tomato plants were immersed in a more heavily radiolabelled medium. Modified separation techniques were used to achieve enhanced radioactivity recovery rates. This experiment demonstrated the presence of relatively high levels of tentatively identified radioactive zeatin in the Dowex 50 root and stem extracts. Radioactivity in the aqueous extracts was found not to be contributed by cytokinin nucleotides. A final experiment was carried out using decapitated root systems to determine if the root tissue alone could be implicated in the synthesis of cytokinins. Decapitated tomato root systems were supplied with either {8- 14 C}-adenine or {1- 14 C}-isopentenyl pyrophosphate. The ratio of incorporation of {1- 14 C}-isopentenyl pyrophosphate into identified cytokinins was higher than for {8- 14 C}-adenine. It was concluded that both adenine and isopentenyl pyrophosphate are involved in the biosynthetic pathway leading to an accumulation of free zeatin derivatives in tomato roots

  14. Synthesis of [methyl-[sup 14]C]-N-methylputrescine

    Energy Technology Data Exchange (ETDEWEB)

    Secor, H.V.; Izac, R.R.; Hassam, S.B.; Frisch, A.F. (Philip Morris Research Center, Richmond, VA (United States))

    1994-05-01

    [Methyl-[sup 14]C]-N-methylputrescine was prepared from [[sup 14]C]methylamine hydrochloride in five steps. Reaction of benzaldehyde and [[sup 14]C]methylamine (10 mCi) followed by catalytic hydrogenation yielded [methyl-[sup 14]C]-N-methylbenzylamine. The key step in this process is the alkylation of [methyl-[sup 14]C]-N-methylbenzylamine in aqueous medium with 4-bromobutyronitrile. The radiochemical purity of the final product after two successive catalytic hydrogenations was in excess of 97%. The radiochemical yields in two successive runs were 26 and 38%, based on starting [[sup 14]C]methylamine, with specific activities of 22 and 23 mCi/mmol, respectively. This sequence provides a convenient and efficient regioselective radiosynthesis of [methyl-[sup 14]C]-N-methylputrescine. (author).

  15. 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

  16. Distribution of photosynthetically fixed 14C in perennial plant species of the northern Mojave Desert

    International Nuclear Information System (INIS)

    Wallace, A.; Cha, J.W.; Romney, E.M.

    1980-01-01

    The distribution of photosynthate among plant parts subsequent to its production is needed to fully understand behavior of vegetation in any ecosystem. The present study, undertaken primarily to obtain information on transport of assimilates into roots of desert vegetation, was conducted in the northern Mojave Desert, where the mean annual rainfall is about 10 cm. Shoots of Ambrosia dumosa (A. Gray) Payne plants were exposed to 14 CO 2 in 1971, and the distribution of 14 C in roots, stems, and leaves was subsequently measured at 1 week, 2 months, and 5 months. Only about 12 percent of the 14 C photosynthate was stored in the root. Much of that stored in stems was available for new leaf growth. Photosynthate was labeled with 14 C for 24 plants representing eight species in 1972. Results showed that after 127 days the mean percentage of 14 C in roots as compared with the estimate of that originally fixed was 11.8; the percentage in stems was 43.8. To check the validity of the 14 C data, root growth of eight perennial desert plants grown in the glasshouse was followed as plants increased in size. The mean percent of the whole plant that was root for eight species was 17.7 percent. The mean proportion of the increase in plant weights that went below ground for the eight species was 19.5 percent. This value is higher than the fraction of 14 C found below ground, and therefore the 14 C technique underestimates the movement of C to roots. Results of an experiment designed to test the value of the 14 C-pulse technique for determining current root growth for some perennial species from the desert indicated that the transition part of roots where root growth continued after exposure to 14 C was highly labeled. Old growth contained less 14 C than new growth

  17. Fate of 14C-labelled compounds in marine environment

    International Nuclear Information System (INIS)

    Kale, S.P.; Raghu, K.; Sherkhane, P.D.; Murthy, N.B.K.

    1999-01-01

    Model ecosystems have played an important role in predicting environmental behavior of agrochemicals. The microcosms used in these studies generally include soil units containing usual biotic components common for that ecosystem. In present studies, scope of two such ecosystems has been extended to study the fate of 14 C-labelled pesticides in marine environment. 14 C-labelled pesticides used in these studies were chlorpyrifos, DDT and HCH. Two systems were developed in laboratory simulating marine environment to study the fate of these pesticides. The first system was developed in an all glass aquarium tank with marine sediments, seawater, clams and algae and is referred to as marine ecosystem. The second system was developed to permit the total 14 C-mass balance studies. It contained marine sediments under moist (60% water holding capacity) or flooded conditions and it is referred to as continuous flow system. Fate of 14 C-DDT was studied in marine ecosystem while degradation of 14 C-chlorpyrifos and 14 C-HCH was studied in continuous flow system. 14 C-DDT did not bioaccumulate in clams while at the end of 60 days 50% of the applied 14 C-activity was present in sediment fraction of marine ecosystem. 14 C-HCH degradation showed about 22-26% mineralization while 45-55% of the applied activity was recovered as organic volatiles. No significant bound residues were formed. 14 C-chorpyrifos underwent considerable degradation in marine environment. TCP was the major degradation product. (author)

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

    Science.gov (United States)

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

    2017-12-01

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

  19. MIN 14C UBT: A combination of gastric basal transit and 14C-urea breath test for the detection of helicobacter pylori infection in human beings

    International Nuclear Information System (INIS)

    Zubillaga, M.; Oliveri, P.; Calcagno, M.L.; Goldman, C.; Caro, R.; Mitta, A.; Degrossi, O.; Boccio, J.

    1997-01-01

    The purpose of this work is to demonstrate that the 14 C-urea breath test (UBT) performed at different times combined with the study of the gastric basal transit, which evaluates the intragastric displacement of a labeled solution under fasting conditions, has the advantage of being representative of the whole stomach surface and constitutes a non-aggressive test for the detection of H. pylori. This test, which has been called MIN 14 C UBT, is a modification of the conventional 14 C UBT in which low volumes of a solution of 14 C-urea together with 99m Tc-sulfur colloid are administered. The 99m Tc-sulfur colloid is not absorbed in the gastrointestinal tract and has the great advantage of allowing the 'visualization' of the transit of the 14 C-urea within the gastrointestinal tract. This modification allows the simultaneous determination of the production of the 14 CO 2 and the place where this process occurs. The results show that there is a good correlation between the images obtained and the breath samples collected. We found that this test has a sensitivity of 98% and a specificity of 96% for H. pylori detection

  20. Behaviour of 14C-sulfadiazine and 14C-difloxacin during manure storage

    International Nuclear Information System (INIS)

    Lamshoeft, Marc; Sukul, Premasis; Zuehlke, Sebastian; Spiteller, Michael

    2010-01-01

    The persistence of sulfadiazine, difloxacin, and their metabolites has been investigated in stored manure. The manure collected from sulfadiazine ( 14 C-SDZ) and difloxacin ( 14 C-DIF) treated pigs contained N-acetylsulfadiazine (Ac-SDZ), 4-hydroxy-SDZ (4-OH-SDZ), and sarafloxacin (SARA) as the main metabolites, respectively along with their parent compounds. Manures were stored separately at 10 o C and 20 o C at various moisture levels. About 96-99% of the radioactivity remained in extractable parent compounds and their metabolites after 150 d of storage. The formation of non-extractable residue and the rate of mineralization were both negligible in manure containing SDZ and DIF. During storage SDZ concentration increased as a result of the deacetylation of Ac-SDZ, whose concentration decreased proportionally. Hence the environmental effects may be underestimated if the parent compound alone is considered for environmental risk assessment. About 11% and 14% of 4-OH-SDZ were lost after 20 and 40 d of storage; thereafter its concentration increased relatively, highlighting hydroxylation of SDZ. DIF degraded very slowly (7% loss after 150 d) during the storage of manure; in contrast the concentration of SARA decreased rapidly (72-90% loss after 150 d). Dilution of manure and storage at higher temperatures for a reasonable period of time enhanced the rate of reactions of SDZ, DIF and their related metabolites.

  1. Disposition and metabolism of 14C citrinin in pregnant rats

    International Nuclear Information System (INIS)

    Reddy, R.V.; Hayes, A.W.; Berndt, W.O.

    1982-01-01

    Citrinin is a product of fungal metabolism capable of producing nephrotoxicity. Distribution, excretion and metabolism of ( 14 C) citrinin was studied in pregnant female rats after subcutaneous administration of 35 mg/kg on the 12th day of gestation. Elimination of ( 14 C) citrinin-derived radioactivity from plasma was biphasic. The half-lives of the rapid (α) and slower (β) plases of elimination were 1.95 h and 39.7 h, respectively. Approximately 74% of the radioactivity appeared in the urine in the first 24 h, with only 1.7% and 1.4% in the urine at 48 h 72 h, respectively. Fecal elimination accounted for 9.5%, 4.1% and 7.3% of the total radioactivity at each of these times. At least one metabolite of citrinin was demonstrable with high performance liquid chromatography (HPLC) of plasma extracts. Retention times for the parent compound and metabolite were 270 s and 175 s, respectively. The metabolite was more polar than the parent compound. At least 3 metabolites of citrinin were found in urine of the same rats. Retention times for two metabolites were 140 s and 180 s, with both metabolites more polar than the parent compound. Chromatograms of bile samples suggested at least one metabolite was present with a retention time of 140 s. Chromatograms of uterus extracts indicated the presence of one metabolite with a retention time of 180 s. Chromatograms of fetus extracts indicated that no metabolites of citrinin were present. (author)

  2. 14C Carbofuran residue in rice-fish ecosystem model

    International Nuclear Information System (INIS)

    Sumatra, M.; Soekarna, D.; Suhanda; Kuswadi, A.N.

    1988-01-01

    14-C-carbofuran in the form of 14-C-Furada 3G was applied with doses of 0, 2, and 4 g/m2 to a rice-fish ecosystem model consisting of water, soil, rice, plant, and fish (Cyprinus carpio) in tanks of the size 1 m length, 1 m width, and 0.5 m depth. 14-C-carbofuran was released from 14-C-Furadan 3G, entered into the water, absorbed by plant root, and then distributed into the whole plant. A part of the 14-C-carbofuran was absorbed and retained by soil. In both doses of 4 and 2 g/m2, the 14-C-Furadan 3G was toxic to Cyprinus carpio under this experiment condition. (author). 5 refs, 5 figs, 6 tabs

  3. Transfer of 14C to prenatal and neonatal rats from their mothers exposed to 14C compounds by ingestion

    International Nuclear Information System (INIS)

    Takeda, H.; Fuma, S.; Miyamoto, K.; Kuroda, N.; Inaba, J.

    2003-01-01

    The transfer of 14 C through placenta or milk was investigated and the radiation dose to fetal and newborn rats was estimated. Female rats at gestational stages or after delivery were exposed to 14 C in the form of sodium bicarbonate, thymidine and lysine by a single ingestion. Radioactivity in maternal tissues and conceptuses (placenta, fetal membrane and fetus) and in the newborn was determined at various times after ingestion. After exposure to these 14 C compounds, there was no significant difference between the 14 C concentration in the fetus and that in the maternal tissues, suggesting that the placenta has no effect in preventing or accelerating the placental transfer of 14 C. The concentration and content of 14 C in the fetus and newborn were, however, dependent on the chemical form of 14 C and on the prenatal or neonatal stage at the time of ingestion. The result of the dose estimation showed that 14 C-lysine gave significantly higher prenatal and neonatal doses than 14 C-sodium bicarbonate or 14 C-thymidine. (author)

  4. Confirmation of eradication of Helicobacter pylori infection by 14C-urea breath test

    International Nuclear Information System (INIS)

    Pathak, C.M.; Bhasin, D.K.; Sharma, B.C.; Roy, P.; Vaiphei, K.

    1998-01-01

    Helicobacter pylori (H. pylori) is a potent urease producer, a characteristic that has been exploited in the development of the 14 C-urea breath test (UBT). 14 C-UBT is being used as a highly reliable test for the diagnosis of H. pylori infection. There is paucity of reports on the utility of this test to confirm the H. pylori eradication after its treatment. The study was conducted to determine the utility of 14 C-UBT in confirming the eradication of H. pylori

  5. Turnover of 14C-glucose in soils and its relationship with soil characters

    International Nuclear Information System (INIS)

    Ni Jinzhi; Xu Jianmin; Xie Zhengmiao; Ye Qingfu

    2001-01-01

    The turnover of 14 C-glucose added in 13 soils was studied. The turnover rate of 14 C-glucose can be divided into three phases: 0 - 3d, 3 - 28d and 28 - 294d. The range of the turnover rate and half -life of 14 C-glucose were 1.3 x 10 -1 - 2.5 x 10 -1 d -1 and 3 - 5d, 0.7x 10 -2 - 1.2 x 10 -2 d -1 and 58 - 97d, 0.5 x 10 -3 - 1.4 x 10 -3 d -1 and 491 - 1504d, respectively. Correlation analysis showed that from 0 to 3 days the turnover rate of 14 C-glucose had significant positive correlation with soil qCO 2 , from 3 to 28 days, the turnover rate of 14 C-glucose had no significant correlation with soil physico-chemical and biological properties. The turnover rate of 14 C-glucose had significant or highly significant negative correlation with soil total organic carbon, total nitrogen, CEC and significant positive correlation with soil sand content during the period from 28 to 294 days. Turnover of 14 C-glucose during the third period has close correlation with soil properties

  6. A study on alfalfa-dodder relationships by 14C-sucrose incorporation in their tissues

    International Nuclear Information System (INIS)

    Tsenova, M.

    1975-01-01

    Plant-parasite relationships between lesser-dodder (Cuscuta epithymum) and alfalfa (Medicago sativa) are investigated. 14 C-sucrose was incorporated via the cut stems of host and parasite into their tissues and the content of the free sugars, keto acids and free amino acids are determined. 14 C-sucrose was introduced also in lesser-dodder previously taken from the host-plant and immersed directly into radioactive sucrose. It is shown that the parasite intensively absorbs sucrose from the host-plant tissues using it as a source of energy and as a substrat for different synthetic processes. In the case when the parasite was previously taken away from the host-plant 14 C-sucrose taken up directly from the solution was used for the synthesis of various compounds (carbohydrates, amino- and keto acids). The suggestion was made that the respective enzyme systems are present in dodder tissues. The 14 C-glucose and 14 C-fructose content is an evidence for high invertase hydrolytic activity. The presence of 14 C-keto acids shows that the 14 C-sucrose incorporated in lesser-dodder tissues without the mediation of the host-plant was used as a respiratory substrate by the degradation following Krebs cycle. (author)

  7. Percutaneous absorption of [14C]DDT and [14C]benzo[a]pyrene from soil

    International Nuclear Information System (INIS)

    Wester, R.C.; Maibach, H.I.; Bucks, D.A.; Sedik, L.; Melendres, J.; Liao, C.; DiZio, S.

    1990-01-01

    The objective was to determine percutaneous absorption of DDT and benzo[a]pyrene in vitro and in vivo from soil into and through skin. Soil (Yolo County 65-California-57-8; 26% sand, 26% clay, 48% silt) was passed through 10-, 20-, and 48-mesh sieves. Soil then retained by 80-mesh was mixed with [14C]-labeled chemical at 10 ppm. Acetone solutions at 10 ppm were prepared for comparative analysis. Human cadaver skin was dermatomed to 500 microns and used in glass diffusion cells with human plasma as the receptor fluid (3 ml/hr flow rate) for a 24-hr skin application time. With acetone vehicle, DDT (18.1 +/- 13.4%) readily penetrated into human skin. Significantly less DDT (1.0 +/- 0.7%) penetrated into human skin from soil. DDT would not partition from human skin into human plasma in the receptor phase (less than 0.1%). With acetone vehicle, benzo[a]pyrene (23.7 +/- 9.7%) readily penetrated into human skin. Significantly less benzo[a]pyrene (1.4 +/- 0.9%) penetrated into human skin from soil. Benzo[a]pyrene would not partition from human skin into human plasma in the receptor phase (less than 0.1%). Substantivity (skin retention) was investigated by applying 14C-labeled chemical to human skin in vitro for only 25 min. After soap and water wash, 16.7 +/- 13.2% of DDT applied in acetone remained absorbed to skin. With soil only 0.25 +/- 0.11% of DDT remained absorbed to skin. After soap and water wash 5.1 +/- 2.1% of benzo[a]pyrene applied in acetone remained absorbed to skin. With soil only 0.14 +/- 0.13% of benzo[a]pyrene remained absorbed to skin

  8. Environmental background 14C levels in Japan in 1990s

    International Nuclear Information System (INIS)

    Fuma, Shoichi; Inoue, Yoshikazu; Miyamoto, Kiriko; Takeda, Hiroshi; Iwakura, Tetsuo; Arai, Kiyohiko; Kashida, Yoshihiko; Ichimasa, Yusuke

    2002-01-01

    For assessment of radiation doses due to 14 C released from nuclear facilities, it is necessary to know the background level of environmental 14 C originated from the natural cosmic-ray production and the past atmospheric nuclear weapons tests. The authors selected grapes as an indicator of 14 C levels in the environment including atmosphere, and determined the specific activities of 14 C in ethanol extracted from wine made from grapes cultivated in several prefectures or unknown places in Japan in each year from 1990 to 2000. The specific activities of 14 C were almost uniform all over Japan in each year, though they showed the weak tendency to slightly decrease with increasing population densities in the prefecture where the wine grapes were cultivated. It is considered that this small regional variation in the specific activities of 14 C arose from Suess effect, because population densities can be regarded as an index of the amount of CO 2 emission from fossil-fuel combustion. The specific activities of 14 C gradually decreased in the 1990s. That is, they were 260 mBq/gC in 1990, and became 244 mBq/gC in 2000. This 14 C level in 2000 was still about 7% higher than the pre-bomb level. The decrease in 14 C originated from the past atmospheric nuclear weapons tests could be described by a single exponential function with a half-time of 10.3 years in 1990s. This half-time was shorter than that in the Europe, Canada and the South Pacific. This difference in the decreasing rate between Japan and other countries may be explained by a fact that the amount of CO 2 emission from fossil-fuel combustion continued to increase in Japan in this period. The specific activities of 14 C in wine ethanol determined in this study showed good agreement with those in atmospheric CO 2 predicted by a mathematical model. They were also in the same levels as the 14 C specific activities in atmospheric CO 2 , tree leaves, grass and plant food in Japan and other countries, which were

  9. Root-uptake of {sup 14}C derived from acetic acid and {sup 14}C transfer to rice edible parts

    Energy Technology Data Exchange (ETDEWEB)

    Ogiyama, Shinichi [Office of Biospheric Assessment for Waste Disposal, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi 263-8555 (Japan)], E-mail: ogiyama@nirs.go.jp; Suzuki, Hiroyuki [Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba-shi 263-5522 (Japan); Inubushi, Kazuyuki [Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo-shi 271-8510 (Japan); Takeda, Hiroshi; Uchida, Shigeo [Office of Biospheric Assessment for Waste Disposal, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi 263-8555 (Japan)

    2010-02-15

    Three types of culture experiments using paddy rice (Oryza sativa L.) were performed to examine root-uptake of {sup 14}C in the form of acetic acid: double pot experiment (hydroponics), wet culture experiment (submerged sand medium), and chamber experiment (hydroponics and submerged sand medium). The {sup 14}C radioactivity in the plant, mediums, and atmospheric carbon dioxide ({sup 14}CO{sub 2}) in the chamber were determined, and the distribution of {sup 14}C in the plant was visualized using autoradiography. In the double pot experiment, the shoot of the plant and the lower root which was soaked in the culture solution had {sup 14}C radioactivity, but the upper root which did not have contact with the solution had none. There were also {sup 14}C radioactivity in the grains and roots in the wet culture experiment. Results of the chamber experiment showed that {sup 14}CO{sub 2} gas was released from the culture solution in both types of cultures. Results indicated that the {sup 14}C-acetic acid absorbed by rice plant through its root would be very small. Most of the {sup 14}C-acetic acid was transformed into gaseous forms either in the culture solution or rhizosphere. A relatively longer time would be needed to assimilate {sup 14}C derived from acetic acid to grain parts after it was once absorbed by the shoot through the root. Availability of {sup 14}C for the plant in sand culture was considered to be decreased compared with that for the plant in the hydroponics experiment. It was suggested that rice plant absorbed and assimilated {sup 14}C through the plant roots not because of uptake of {sup 14}C-acetic acid but because of uptake of {sup 14}C in gaseous forms such as {sup 14}CO{sub 2}.

  10. Metabolism of [ 14 C]GA 19 and [ 14 C]GA 53 by ecotypes of Betula ...

    African Journals Online (AJOL)

    Continuing with this line of research, we studied the metabolism of 14C-labelled GA19 and GA53. [14C]GA19 and [14C] A53 were applied to the apices of the northern ecotype (67º N) and to the leaves of the southern ecotype (64º N) of Betula pendula Roth. under different photoperiods and at different times in order to ...

  11. Root-uptake of 14C derived from acetic acid and 14C transfer to rice edible parts

    International Nuclear Information System (INIS)

    Ogiyama, Shinichi; Suzuki, Hiroyuki; Inubushi, Kazuyuki; Takeda, Hiroshi; Uchida, Shigeo

    2010-01-01

    Three types of culture experiments using paddy rice (Oryza sativa L.) were performed to examine root-uptake of 14 C in the form of acetic acid: double pot experiment (hydroponics), wet culture experiment (submerged sand medium), and chamber experiment (hydroponics and submerged sand medium). The 14 C radioactivity in the plant, mediums, and atmospheric carbon dioxide ( 14 CO 2 ) in the chamber were determined, and the distribution of 14 C in the plant was visualized using autoradiography. In the double pot experiment, the shoot of the plant and the lower root which was soaked in the culture solution had 14 C radioactivity, but the upper root which did not have contact with the solution had none. There were also 14 C radioactivity in the grains and roots in the wet culture experiment. Results of the chamber experiment showed that 14 CO 2 gas was released from the culture solution in both types of cultures. Results indicated that the 14 C-acetic acid absorbed by rice plant through its root would be very small. Most of the 14 C-acetic acid was transformed into gaseous forms either in the culture solution or rhizosphere. A relatively longer time would be needed to assimilate 14 C derived from acetic acid to grain parts after it was once absorbed by the shoot through the root. Availability of 14 C for the plant in sand culture was considered to be decreased compared with that for the plant in the hydroponics experiment. It was suggested that rice plant absorbed and assimilated 14 C through the plant roots not because of uptake of 14 C-acetic acid but because of uptake of 14 C in gaseous forms such as 14 CO 2 .

  12. Method of preparing D-mannose(U-14C) from glucons(U-14C) separated from natural material

    International Nuclear Information System (INIS)

    Kucar, S.; Zemek, J.; Bilik, V.; Kolina, J.

    1981-01-01

    Glucans(U- 14 C) separated from green or blue-green algae are hydrolysed using diluted mineral acids in the presence of small amounts of molybdate ions to D-glucose(U- 14 C) which, at a temperature of 60 to 100 degC epimerizes to D-mannose(U- 14 C). The epimeric aldoses are separated from the reaction mixture by paper chromatography. (H.S.)

  13. Influence of pesticide applications on degradation of the herbicide 14C - 2,4-D in different soils

    International Nuclear Information System (INIS)

    Marcondes, Marcilio Amaral

    2001-01-01

    Despite the importance of pesticide usage for the food production, its indiscriminate use may cause changes in the soil fertility, because pesticides influence soil microorganisms which are important for the biogeochemical cycles. The influence of applications of several pesticides, as recommended for cotton culture, was studied on the bioactivity of different soils (from Sao Paulo and Tatui, SP) by using radiometric techniques and a closed system for detection of bio mineralization of ''1 4 C-2,4-D ( 14 C-2,4-dichlorophenoxyacetic acid) and production of 14 C-volatile compounds. The 14 C-2,4-D dissipation under influence of other pesticide applications was also studied by determination of 14 C-extractable residues, 14 C-bound residues and qualitative and quantitative analysis of the 14 C-extractable residues by high pressure liquid chromatography (HPLC) and thin layer chromatography (TLC). 14 C-volatile compounds were never detected but increases and decreases of bio mineralization were detected in both soils after different treatments. The mixture of deltamethrin + methyl parathion increased significantly the bioactivity in both soils; nevertheless, monocrotophos did not have any influence. The applications of different pesticides have also influenced the 14 C-2,4-D dissipation, because the radiocarbon recovered as 14 C-extractable residues differed between the treated and untreated samples of both soils. On the other hand, the pesticide applications did not influence the production of 14 C-bound residues. This 14 C-residue was produced in larger amounts by the richest in organic matter soil (Sao Paulo). Although radiocarbon had been detected not only as 14 'C-2,4-D but also as a 14 C-metabolite, in both soils and treatments, results indicate that the ' 14 C-2,4-D dissipation varied in the two studied soils and was influenced by treatments with others pesticides. (author)

  14. {Delta}{sup 14}C level of annual plants and fossil fuel derived CO{sub 2} distribution across different regions of China

    Energy Technology Data Exchange (ETDEWEB)

    Xi, X.T.; Ding, X.F.; Fu, D.P. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Zhou, L.P. [Laboratory for Earth Surface Processes, Department of Geography, Peking University, Beijing 100871 (China); Liu, K.X., E-mail: kxliu@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2013-01-15

    The {sup 14}C level in annual plants is a sensitive tracer for monitoring fossil fuel derived CO{sub 2} in the atmosphere. Corn leave samples were selected from different regions of China, including high mountains in the Tibetan Plateau, grassland in Inner Mongolia, and inland and coastal cities during the summer of 2010. The {sup 14}C/{sup 12}C ratio of the samples was measured with the NEC compact AMS system at the Institute of Heavy Ion Physics, Peking University. The fossil fuel derived CO{sub 2} was estimated by comparing the measured {Delta}{sup 14}C values of corn leave samples to background atmospheric {Delta}{sup 14}C level. The influences of topography, meteorological conditions and carbon cycling processes on the fossil fuel derived CO{sub 2} concentration are considered when interpreting the data. Our results show a clear association of the low {Delta}{sup 14}C values with regions where human activities are intensive.

  15. Synthesis of [14C]-62514, a radiolabelled derivative of erythromycin A, via [2-14C]N,N-dimethylethylenediamine

    International Nuclear Information System (INIS)

    Surber, B.W.; Baker, W.R.; Seif, L.

    1991-01-01

    The synthesis of [ 14 C]A-62514, 11-deoxy-11[carboxy(2-dimethylamino-[1- 14 C]ethyl)amino]-6-0-methyl-e rythromycin A 11,12-(cyclic ester), was performed in five steps. The key intermediate, [2- 14 C]N,N-dimethylethyl-enediamine, was obtained in 80% yield by reacting Eschenmoser's salt with K 14 CN and reducing the resulting [1- 14 C]N,N-dimethylglycinonitrile with H 2 and Raney Ni in methanol and ammonium hydroxide. The final product was obtained 97% radiochemically pure in an overall radiochemical yield of 14%, with a specific activity of 39 mCi/mmol. (author)

  16. Synthesis and characterization of 14C polyvinylphosphonic acid

    International Nuclear Information System (INIS)

    Stringer, O.D.; Charig, A.

    1989-01-01

    Ten mCi of 14 C ethylene was converted to 1.16 mCi of 14 C PVPA by oxidative phosphonation with phosphorus trichloride and molecular oxygen, dehydrohalogenation with triethylamine in ether, polymerization, and hydrolysis. The polymer had a specific activity of 12 uCi/mg and a radiochemical purity over 99%. (Author)

  17. Synthesis of /sup 14/C-labelled milrinone

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, D.R.; Johnston, D.; Andrews, R.S. (Stirling-Winthrop, Alnwick (UK). Research and Development Div.)

    1985-02-01

    A synthetic procedure for producing /sup 14/C-labelled milrinone, a potent new cardiotonic agent, is described. The synthesis was achieved in two steps from 1-(4-pyridyl)propan-2-one utilising (2-/sup 14/C)cyanoacetamide as the source of the radiolabel. The overall chemical yield was 46% and the radiochemical yield 35%.

  18. Synthesis of specific labelled [methyl-14C]sarin

    International Nuclear Information System (INIS)

    Sin-Ren, A.C.; Riggio, G.; Hopff, W.H.; Waser, P.G.

    1988-01-01

    The synthesis of [methyl- 14 C]sarin ([ 14 C]methylphosphono-fluoridic acid 1-methylethyl ester) was accomplished by another approach as for nonlabelled sarin in a tele-conducted reaction vessel. The purity was estimated by IR, GC, and GC-MS and the stability in different media was examined. (author)

  19. Application of AMS 14C measurements to criminal investigations

    International Nuclear Information System (INIS)

    Nakamura, T.; Ohta, T.; Nishida, M.; Rakowski, A.; Ikeda, A.; Oda, H.; Kojima, S.

    2007-01-01

    14 C variations of atmospheric CO 2 as well as carbonaceous fraction of living materials, such as collagen from tooth and bone, tissue, skin, hair, nail, etc., of modern humans are influenced by 14 C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of 14 C concentration of tree rings and human body samples formed in this time intervals, we can establish a relationship of their 14 C concentrations with calendar year. By applying this relation to a sample whose 14 C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the chemicals that were used in some criminal cases can be possibly identified, by their carbon isotope ratios ( 13 C/ 12 C and 14 C/ 12 C). This method of age determination has been applied to a forensic study, i.e., two criminal cases of murder. For each case, by comparing the measured 14 C abundances of several pieces of hair and one tooth (the third molar) from the body with the annual change on concentrations of bomb-produced 14 C, the time of death of the body and the age of the victim were estimated. The estimated values were consistent with the real ones that were revealed by the confession of the real murderers. (author)

  20. 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)

  1. 14 C dating by using mass spectrometry with particle accelerator

    International Nuclear Information System (INIS)

    Santos, G.M.; Gomes, P.R.S.; Yokoyama, Y.; Tada, M.L. di; Cresswell, R.G.; Fifield, L.K.

    1999-01-01

    The different aspects concerning the 14 C dating are described, including the cosmogenic origin of 14 C, its production and absorption by matter, the procedures to be followed for the age determination and the associated errors, particularly by the Accelerator Mass Spectrometry (AMS) technique, and the different steps of the sample preparation process. (author)

  2. Fate of [14C]-zineb on lettuce plants

    International Nuclear Information System (INIS)

    Vonk, J.W.

    1976-01-01

    [1,2- 14 C]-zinc ethylenebisdithiocarbamate (zineb) was prepared and applied in droplets to leaves of lettuce plants. In aqueous suspension zineb decomposes mainly into ethylenethiourea (ETU) and 5,6-dihydro-3H-imidazo[2,1-C]-1,2,4-dithiazole-3-thione (DIDT). Lettuce plants were harvested 0,1,3,7,14 and 21 days after treatment and analysed. A high proportion of radioactivity remained on the surface of the plant and could be washed off. The following identified products were present: unchanged zineb, ETU, DIDT, 2-imidazoline and ethyleneurea. The ETU residue disappeared within 7 days, while 2-imidazoline and ethyleneurea were formed gradually. Radioactivity inside the plant consisted mostly of ethyleneurea: no ETU was present. (author)

  3. Oxidation of propionic acid-3-14C with alkaline permanganate

    International Nuclear Information System (INIS)

    Zielinski, M.

    1981-01-01

    The mechanism of oxidation of propionic acid with permanganate in alkaline medium was reinvestigated using methyl- 14 C labelled propionate. The preferential rupture of the αC-βC bond in propionate in highly concentrated alkaline solutions of NaOH (and KOH) was confirmed and the appearance of 14 C-labelled oxalate explained by the formation of the symmetrical intermediate which decomposes in two different modes. (author)

  4. Removal of 14C from nitrogen annulus gas

    International Nuclear Information System (INIS)

    Cheh, C.H.

    1985-01-01

    A dry, ambient temperature process using Ca(OH) 2 as the sorbent to remove 14 CO 2 from moderator cover gas was further developed to remove 14 C from the extremely dry nitrogen annulus gas. Thermal gravimetric analysis was carried out to study the thermal stability of Ca(OH) 2 and the CO 2 -Ca(OH) 2 reaction at elevated temperatures under extremely low humidity conditions. Results shows that to achieve high utilization and avoid decomposition of Ca(OH) 2 , humidification of the annulus gas was necessary at high or low temperatures. Results of the bench scale (1-10 L/min) oxidizer study showed that, with 0.5% Pd or alumina as the catalyst, it was possible to achieve complete oxidation of CO and over 80% oxidation of CH 4 with 1% hydrogen in the nitrogen. The gas superficial velocity should be less than or equal to30 cm/s and the residence time greater than or equal to0.5 s. A pilot scale (up to 160 L/min) system including a catalytic oxidizer, a humidifier/demister, a Ca(OH) 2 reactor, a condenser/demister and regenerable molecular sieve dryers, was assembled and tested with simulated nitrogen annulus gas. Results showed that complete oxidation of the CO and 60-100% oxidation of the CH 4 with 0.5% H 2 in the simulated gas were achieved in the pilot plant. The CO 2 concentration was reduced from 30-60 μL/L at the inlet of the Ca(OH) 2 reactor to 1 μL/L or less at the outlet. After modifications of the dryer to overcome the problems encountered, the simulated annulus gas was dried to 0 C dew point before recirculation. Equipment specifications and operating conditions of a 14 C removal system for nitrogen annulus gas are summarized

  5. Behavior of 14C-BHC residues in rice grain

    International Nuclear Information System (INIS)

    Lee, S.R.; Kim, Y.H.

    1981-01-01

    γ-(U- 14 C)-BHC was applied to rice plants grown in a pot and its fate in the growth, polishing and oil-extraction processes of the grain was investigated. The 14 C-activity was absorbed and translocated widely in the plant and the recovery of applied 14 C-activity in the straw and grain was about 2.8%, of which 9.4% was found in the brown rice. The % partitioning of 14 C-residues in bran and polished rice was 12:88 and that in oil and oilcake was 37:63. Characterization of 14 C-residues the presence of γ-BHC, pentachlorocyclohexene, trichlorobenzene and hydrophilic metabolites, whose proportions were different in the straw and grain. (Author)

  6. Rectal absorption of homatropine [14C] methylbromide in the rat

    International Nuclear Information System (INIS)

    Cramer, M.B.; Cates, L.A.; Clarke, D.E.

    1978-01-01

    Homatropine [ 14 C]methylbromide (HMB- 14 C) was administered to rats by intramuscular injection, oral gavage and rectal suppository. Plasma concentrations of 14 C were measured over the subsequent 12 h. Peak plasma concentrations were higher and achieved more rapidly after rectal administration than by other routes whether HMB- 14 C was administered in a water-soluble suppository base or in aqueous solution. Twelve h after the suppositories were inserted and retained 28% of the 14 C had been excreted in the urine while 56% remained in the large intestine. Unlabelled HMB, given in rectal suppositories to anaesthetized rats, caused prompt blockade of the effects of vagal stimulation on pulse rate and of intravenous acetylcholine on blood pressure. These results confirm the rapid rectal absorption of the drug. (author)

  7. Radiocarbon 14C differentiation of sparkling and carbonated wines

    International Nuclear Information System (INIS)

    Martin, G.E.; Krueger, H.W.; Burggraff, J.M.

    1985-01-01

    Specific 14 C-activities, percent of modern 14 C-activity, and calculated percent of fermentation CO 2 are presented for CO 2 contained in commercial sparkling wines, labeled as champagne or produced by the bulk (charmat) process. These data are given for the production years 1976-1982. The survey encompassed effervescent wines produced in Spain, Italy, West Germany, California, and New York. Addition of synthetic CO 2 to approximately 40 samples represented as sparkling wines was indicated by low 14 C-activities of CO 2 in these wines. Data for 14 C-activity were also presented for the ethanol distilled from sparkling wines for the years 1977-1980. In all cases, the 14 C-activity of ethanol was appropriate to the year of vintage

  8. Synthesis of phenobarbital {sup 14}C - 5 (1964); Synthese du phenobarbital {sup 14}C - 5 (1964)

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    Phenobarbital (Luminal), well known as a hypnotic agent, plays also an important role in the medical treatment of epilepsy. With the object of studying the metabolism of this medicament in the living system, the synthesis of phenobarbital marked in position 2 of the pyrimidinic ring has been effected. It has been necessary, in order to carry out to research into the metabolism of this product, to have a phenobarbital marked in position 5 of the pyrimidinic ring. This synthesis, making it possible to introduce C-14 into position 5 of the pyrimidinic ring, consists of seven stages starting from C-14 carboxyl benzoic acid having a specific activity of 25 mc/mM. The melting point of the final product is 172 - 173 deg. C and its specific activity is 11.15 mc/mM. The overall radioactive yield of the pure product, with respect to the original benzoic acid (10 mM) is of the order of 3 per cent. The purity of the product has been controlled by paper chromatography; it is of the order of 99 per cent. (author) [French] Le phenobarbital (Luminal) bien connu comme agent hypnotique, joue egalement un role important dans la medication anti-epileptique. Pour l'etude du metabolisme de ce medicament dans l'organisme vivant, nous avons synthetise le phenobarbital marque en position 2 du cycle pyrimidinique. Afin de poursuivre la recherche du metabolisme de ce produit, il a ete necessaire de disposer du phenobarbital marque en position 5 du cycle. pyrimidinique. Cette synthese, permettant l'introduction du {sup 14}C en position 5 du cycle pyrimidinique, comporte sept etapes, au depart de l'acide benzoique carboxyle {sup 14}C, d'une activite specifique de 25 mc/mM. Point de fusion du produit final: 172 - 173 deg. C Activite specifique: 11,15 mC/mM. Rendement total radioactif du produit pur, par rapport a l'acide benzoique de depart sur 10 mM, de l'ordre de 3 pour cent. La purete du produit a ete controlee par chromatographie sur papier; elle est de l'ordre de 99 pour cent. (auteur)

  9. Myo-inositol-14C, phytic acid-14C and ferric phytate-14C metabolism through microbian action in an andosol soil

    International Nuclear Information System (INIS)

    Gonzalez I, J.

    1977-01-01

    The myo-inositol- 14 C, phytic acid- 14 C and ferric phytate- 14 C compounds were incubated in an andosol soil at 70% of the field capacity and at 36.5 deg C during twelve days. These compounds suffered a microbian oxidation at 14 CO 2 of 61.0, 1.9 and 0% respectively. The fixation of the phytic acid- 14 C was observed through the fast decrease in the metabolism, due to the formation of complexes with the Fe and Al (phytates). The myo-inositol- 14 C metabolism was reduced by a factor of nine at the second incubation day. The following mechanisms were observed in the myo-inositol metabolism: (i) adsorption of the inositol by the soil minerals, (ii) adsorption by humic acids, (iii) myo-inositol phosphorylation and (iv) epimerization of myo-inositol to chiro-inositol. It was found that the (i) and (ii) formation depends on the soil microbian activity. The (i), (ii) and (iii) interactions were considered as possible mechanisms for the inhibition of the myo-inositol microbian oxidation. The inhibition of the myo-inositol oxidation through adsorption or phosphorylation is considered as a chemical blockade for the hydroaxial group, avoiding this way a microbian oxidation stereospecific of this hydroxil group. (author)

  10. Absorption and translocation of 59Fe and 14C-rhodotorulate in iron-stressed tomato

    International Nuclear Information System (INIS)

    Miller, G.W.; Shigematsu, A.; Motoji, N.; Shibabe, S.

    1990-01-01

    Tomato plants, cultivars FER and Earlygirl (both iron efficient and able to use rhodotorulate- 59 Fe), were grown under low Fe conditions for 9 days. Rhodotorulate- 14 C, isolated from Rhodotorula pilimanae cultured with 14 C-sucrose, and rhodotorulate- 59 Fe were added to the Fe-stressed plants for 6-, 24- or 48-h periods. It was evident from autoradiograms and tissue sampling that 59 Fe and 14 C were abundant in roots, stems and leaves. The 14 C autoradiograms showed especially high density in the small, younger leaves, as was found also with 59 Fe. Unlike synthetic chelates, rhodotorulate (or metabolised derivatives) was readily absorbed by the roots and translocated to the leaves. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

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

  12. A convenient photosynthesis of uniformly [14C]-labelled D-glucose, D-fructose and sucrose, and chemical synthesis of methyl-α-D-glucopyranoside ([U-14C]-glucose)

    International Nuclear Information System (INIS)

    Srinivas, G.; Unny, V.K.P.; Mukkanti, K.; Choudary, B.M.

    2013-01-01

    This paper describes a convenient procedure for the radiochemical preparation of D-[U- 14 C]-glucose, D-[U- 14 C]-fructose and [U- 14 C]-sucrose with high specific activity by photosynthesis using ‘canna indica’ leaf, [ 14 C]-carbon dioxide and water in presence of light in a closed system. The [ 14 C]-sugars formed were extracted, separated and then purified by paper chromatography. Further, the pure D-[U- 14 C]-glucose obtained was converted to methyl-α-D-glucopyranoside ([U- 14 C]-glucose) by glycosidation with methanol using (i) HCl, the conventional Fischer method (ii) heterogeneous organic cation exchange resin (Amberlite IR-120 (H + )) and (iii) heterogeneous inorganic cation exchanged montmorillonites called metal M +n -monts. The results indicated that the latter in the form of Fe +3 -montmorillonite gave a better yield ( 65%) as compared to others (40–56%). The radiochemical purity of the no-carrier added product was more than 98%. The product retained its specific activity as that of the starting material which is in the range of 250–300 mCi/mmole (9.25–11.1 GBq/mmole), suitable for use as a radiotracer in biochemical investigations. - Graphical abstract: A convenient photosynthesis of uniformly [ 14 C]-labelled D-glucose, D-fructose and sucrose, and chemical synthesis of methyl-α-D-glucopyranoside ([U- 14 C]-glucose)/[ 14 C]–AMG, in short. The photosynthesis of D-[U- 14 C]-glucose, and two other [ 14 C]-sugars (fructose and sucrose) with high specific activity using ‘Canna indica’ leaf, 14 CO 2 and water in presence of light is presented in this paper. Further, the D-[U- 14 C]-glucose obtained was converted to methyl-α-D-glucopyranoside ([U- 14 C]-glucose)/[ 14 C]–AMG having 98% radiochemical purity and specific activity in the range of 250–300 mCi/mmole, using montmorillonites (M +n -monts). Highlights: ► Synthesis of methyl α D-glucopyranoside ([U- 14 C] glucose) has not been reported using M +n -monts. ► M +n -monts are

  13. Adsorption characteristics of 14C-labeled alanine, aspartic acid and adenosine triphosphate by metal-chelating resins

    International Nuclear Information System (INIS)

    Ishiyama, Toshio; Matsunami, Tadao; Shibata, Setsuko; Honda, Yoshihide.

    1987-01-01

    (1) Adsorption properties of 14 C-alanine, 14 C-ATP (adenosine triphosphate) and 14 C-aspartic acid on the metal-chelating resins were determined and found that the Cu(II)-Chelex 100 and Fe(III)-Unicellex UR10, Fe(III)-Chelex 100 chelating resins were highly effective for the adsorption of 14 C-alanine and 14 C-ATP, respectively. (2) Desorption rate of 14 C-ATP from the Fe(III)-Unicellex UR10 and Fe(III)-Chelex 100 resins was somewhat higher than the case of 14 C-alanine, probably because the coordination bonds of Cu-alanine might be stronger than those of Fe-ATP. Thus, 14 C-labeled organic compounds such as 14 C-alanine and 14 C-ATP of a low activity concentration (3.7 mBq/ml) (1 x 10 -7 μCi/ml) in aqueous solution may be measured with liquid scintillation counter after pre-concentration by use of the Fe(III)- and Cu(II)-chelating resin columns. (author)

  14. Phase sensitive diffraction sensor for high sensitivity refractive index measurement

    Science.gov (United States)

    Kumawat, Nityanand; Varma, Manoj; Kumar, Sunil

    2018-02-01

    In this study a diffraction based sensor has been developed for bio molecular sensing applications and performing assays in real time. A diffraction grating fabricated on a glass substrate produced diffraction patterns both in transmission and reflection when illuminated by a laser diode. We used zeroth order I(0,0) as reference and first order I(0,1) as signal channel and conducted ratiometric measurements that reduced noise by more than 50 times. The ratiometric approach resulted in a very simple instrumentation with very high sensitivity. In the past, we have shown refractive index measurements both for bulk and surface adsorption using the diffractive self-referencing approach. In the current work we extend the same concept to higher diffraction orders. We have considered order I(0,1) and I(1,1) and performed ratiometric measurements I(0,1)/I(1,1) to eliminate the common mode fluctuations. Since orders I(0,1) and I(1,1) behaved opposite to each other, the resulting ratio signal amplitude increased more than twice compared to our previous results. As a proof of concept we used different salt concentrations in DI water. Increased signal amplitude and improved fluid injection system resulted in more than 4 times improvement in detection limit, giving limit of detection 1.3×10-7 refractive index unit (RIU) compared to our previous results. The improved refractive index sensitivity will help significantly for high sensitivity label free bio sensing application in a very cost-effective and simple experimental set-up.

  15. Effects of Pseudomonas species on the release of bound 14C residues from soil treated with [14C]atrazine

    International Nuclear Information System (INIS)

    Khan, S.U.; Behki, R.M.

    1990-01-01

    The release of bound (nonextractable) 14 C residues from soil previously treated with [ 14 C]atrazine was investigated by incubation of the solvent-extracted soil with two species of Pseudomonas capable of metabolizing atrazine. The two species, 192 and 194, released bound 14 C residues from the soil. Addition of glucose, known to increase microbiological activities, to the incubated soil appeared to enhance the release of soil-bound 14 C residues, in particular in the presence of Pseudomonas species 192. The 14 C bound residues in soil, mainly present as the parent compound and its hydroxy and monodealkylated analogues, were released into the incubation mixture and were subsequently metabolized by the two species involving dechlorination and dealkylation

  16. Dating human DNA with the 14C bomb peak

    Energy Technology Data Exchange (ETDEWEB)

    Kutschera, Walter; Liebl, Jakob; Steier, Peter [VERA Laboratory, University of Vienna, Vienna (Austria)

    2013-07-01

    In 1963 the limited nuclear test ban treaty stopped nuclear weapons testing in the atmosphere. By then the addition from bomb-produced {sup 14}C had doubled the {sup 14}C content of the atmosphere. Through the CO{sub 2} cycle this excess exchanged with the hydrosphere and biosphere leading to a rapidly decreasing {sup 14}C level in the atmosphere. Today we are almost back to the pre-nuclear level. As a consequence all people on Earth who lived during the second half of the 20th century were exposed to this rapidly changing {sup 14}C signal. A few years ago, a group at the Department of Cell and Molecular Biology of the Karolinska Institute in Stockholm started to use the {sup 14}C bomb peak signal in DNA to determine retrospectively the age of cells from various parts of the human body (brain, heart, fat). In a collaboration with this group, we have studied the age of olfactory bulb neurons in the human brain. For this investigation, {sup 14}C AMS measurements were developed at VERA for very small carbon samples in the range from 2 to 4 micrograms. In the presentation the general concept of {sup 14}C bomb peak dating of human DNA and several applications are discussed.

  17. Secretin enhances [14C]erythritol clearance in unanesthetized dogs

    International Nuclear Information System (INIS)

    Lewis, M.H.; Baker, A.L.; Dhorajiwala, J.; Moossa, A.R.

    1982-01-01

    To determine the effect of secretin infusion on clearance of inert markers into bile, unanesthetized dogs fitted with Thomas cannulas received continuous infusions of [ 14 C]erythritol and [ 3 H]inulin throughout study. Taurocholic acid administered sequentially at 9.0, 20.0, and 40.0 mumol/min enhanced [ 14 C]erythritol clearance, and GIH secretin (3 units/min) administered along with TCA (40.0 mumol/min) increased [ 14 C]erythritol clearance from 4.9 +/- 1.2 ml/10 min to 6.8 +/- 1.3 ml/10 min (P less than 0.001), but simultaneously measured [ 3 H]inulin clearance was unaltered. Secretin alone also increased [ 14 C]erythritol clearance but did not alter [ 3 H]inulin clearance. The increase in [ 14 C]erythritol clearance per unit increase in bile flow was less during secretin infusion than TCA. Thus, secretin increases [ 14 C]erythritol transport through restricted channels, probably distal to the canaliculi. [ 14 C]Erythritol may not be an accurate marker for canalicular bile flow in dogs during secretin infusion

  18. TMEM14C is required for erythroid mitochondrial heme metabolism.

    Science.gov (United States)

    Yien, Yvette Y; Robledo, Raymond F; Schultz, Iman J; Takahashi-Makise, Naoko; Gwynn, Babette; Bauer, Daniel E; Dass, Abhishek; Yi, Gloria; Li, Liangtao; Hildick-Smith, Gordon J; Cooney, Jeffrey D; Pierce, Eric L; Mohler, Kyla; Dailey, Tamara A; Miyata, Non; Kingsley, Paul D; Garone, Caterina; Hattangadi, Shilpa M; Huang, Hui; Chen, Wen; Keenan, Ellen M; Shah, Dhvanit I; Schlaeger, Thorsten M; DiMauro, Salvatore; Orkin, Stuart H; Cantor, Alan B; Palis, James; Koehler, Carla M; Lodish, Harvey F; Kaplan, Jerry; Ward, Diane M; Dailey, Harry A; Phillips, John D; Peters, Luanne L; Paw, Barry H

    2014-10-01

    The transport and intracellular trafficking of heme biosynthesis intermediates are crucial for hemoglobin production, which is a critical process in developing red cells. Here, we profiled gene expression in terminally differentiating murine fetal liver-derived erythroid cells to identify regulators of heme metabolism. We determined that TMEM14C, an inner mitochondrial membrane protein that is enriched in vertebrate hematopoietic tissues, is essential for erythropoiesis and heme synthesis in vivo and in cultured erythroid cells. In mice, TMEM14C deficiency resulted in porphyrin accumulation in the fetal liver, erythroid maturation arrest, and embryonic lethality due to profound anemia. Protoporphyrin IX synthesis in TMEM14C-deficient erythroid cells was blocked, leading to an accumulation of porphyrin precursors. The heme synthesis defect in TMEM14C-deficient cells was ameliorated with a protoporphyrin IX analog, indicating that TMEM14C primarily functions in the terminal steps of the heme synthesis pathway. Together, our data demonstrate that TMEM14C facilitates the import of protoporphyrinogen IX into the mitochondrial matrix for heme synthesis and subsequent hemoglobin production. Furthermore, the identification of TMEM14C as a protoporphyrinogen IX importer provides a genetic tool for further exploring erythropoiesis and congenital anemias.

  19. Appraisal of the 14C-glycocholate acid test with special reference to the measurement of faecal 14C excretion

    International Nuclear Information System (INIS)

    Scarpello, J.H.B.; Sladen, G.E.

    1977-01-01

    The 14 C-glycocholate test, including the measurement of marker corrected faecal 14 C, has been assessed in the following groups of subjects: normal controls (18), patients with diarrhoea not attributable to altered bile acid metabolism (21), patients with diverticula of the small intestine (12), patients with previous resection of ileum and often proximal colon (34), and established ileostomists (10). Patients with diverticular disease had increased breath 14 CO 2 excretion, but normal faecal excretion of 14 C, and this test was more frequently abnormal than the Schilling test. Ileostomists excreted increased amounts of faecal 14 C, even when the ileum was intact and apparently normal. The pattern after resection was complex. Breath 14 C output was normal if the ileal resection was less than 25 cm in length, although some of these patients had increased faecal 14 C excretion if, in addition, at least 15 cm of proximal colon had been resected or by-passed. Longer ileal resections were associated with increased breath and/or faecal 14 C excretion, depending in part on the length of colon resected or by-passed and the 24 hour faecal volume. Fewer than half these patients had both increased breath and faecal excretion of isotope and faecal 14 C alone was occasionally normal with an ileal resection of 50 cm or more. The 14 C-glycocholate test was more frequently abnormal than the Schilling test in this group. The use of faecal marker correction had only a minor impact on the results. These data suggest that, in patients with ileal resection, faecal 14 C, like faecal weight, is determined by the extent of colonic resection as well as by the amount of ileum resected. (author)

  20. Application of AMS 14C measurements to criminal investigations

    International Nuclear Information System (INIS)

    Nakamura, T.; Ohta, T.; Nishida, M.; Ikeda, A.; Oda, H.; Kojima, S.; Niu, E.

    2005-01-01

    14 C variations of atmospheric CO 2 as well as carbonaceous materials of human body, such as collagen fractions from teeth and bone, tissue, hair, nail, etc., of modern humans dead or alive, are influenced by 14 C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of 14 C concentration of tree rings and human tissue samples formed in this time ranges, we can establish a relation between their 14 C concentrations and calendar year. By applying this relation to a sample whose 14 C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the drugs that were used in some criminal cases can be possibly identified by the analysis of their carbon isotope ratios ( 13 C/ 12 C and 14 C/ 12 C). This method of age determination was applied to a forensic study; i.e., to two similar cases of murder. One of the two cases is for a dead body of a modern human who was killed in 1978 and buried under the floor of the house owned by the murderer. The body was excavated in 2004 according to the confession by the murderer. 14 C abundances of several pieces of hair and one tooth (the third molar) from the body were measured with accelerator mass spectrometry (AMS), and compared with the annual change on concentrations of bomb-produced 14 C. The time of death of the body was estimated to be at around 1977, and her age was from 30 to 37 years old at that time. These estimations were consistent with the real values that were revealed after the case was solved by the confession of the real murderer who gave himself up to the police. For the other case, 14 C analysis was also consistent with the fact revealed by police investigations as well as by the confession of the real murderer.

  1. A rapid phospholipase A2 bioassay using 14C-oleate-labelled E. coli bacterias.

    Science.gov (United States)

    Meyer, T; von Wichert, P; Weins, D

    1989-02-01

    Two methods of phospholipase A2 determination using 14C-labelled E. coli bacterias as substrate were compared. One method works with a filter membrane for separation of cleaved 14C-oleate from remaining phospholipids, the other uses the well-known thin-layer chromatography for lipid analysis. Some features of human serum phospholipase A2 regarding pH and Ca2+ dependency were investigated. Possible sources of errors were discussed. It was shown that either method can differentiate between normal and pathologically elevated phospholipase A2 levels, but that the filter method is superior in terms of sensitivity and workload.

  2. Synthesis of 14C and 32P double labelled triethylphosphine

    International Nuclear Information System (INIS)

    Kanska, M.; Drabarek, S.

    1979-01-01

    The synthesis of 14 C and 32 P double labelled triethylphosphine has been carried out using red phosphorus [ 32 P] and barium carbonate [ 14 C] as starting materials. The product of the reaction has been separated by gas chromatography. The 32 P radioactivity assay of the obtained product was performed by the liquid scintillation technique. The 14 C radioactivity was determined by the liquid scintillation technique and internal gas counting method. The radioactivity measurements have served to determine the total yield of double labelled triethylphosphine. (author)

  3. Method of preparing pyrimidine derivatives universally labelled with 14C

    International Nuclear Information System (INIS)

    Pritasil, L.; Filip, J.

    1976-01-01

    Sodium salts of beta-keto acid ethyl esters having mole activity higher than 40 mCi/milliatom 14 C are condensed with 14 C-thiourea having mole activity higher than 40 mCi/milliatom 14 C. Condensation proceeds in an anhydrous ethanol medium at a 1:1 molar ratio, with a 40 to 50% yield. Under the above reaction conditions, the radiochemical yield is higher than 20% while in biosynthesis it is 1% and in the chemical synthesis it is 10%. (J.P.)

  4. Absorption, distribution, and metabolism of [14C]chlorpyrifos applied dermally to goats

    International Nuclear Information System (INIS)

    Cheng, T.; Bodden, R.M.; Puhl, R.J.; Bauriedel, W.R.

    1989-01-01

    Radiolabeled chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate] was applied dermally to two male weanling goats, at a dose of 22 mg/kg of body weight. A blood sample was drawn before dosing and every 4 h thereafter. The animals were sacrificed approximately 18 h after dosing, when blood radioactivity levels at 16 h had declined from maximum values (12 h) in both animals. Radioanalysis of blood and selected tissues (liver, kidney, heart, fat, muscle) indicated that radioactivity levels were, in general, very low, ranging from 0.04 ppm (chlorpyrifos equivalents) in muscle to 0.90 ppm in omental fat. Tissue extracts contained 80-96% of the 14 C residue, most of which was organosoluble. High-performance liquid chromatography analysis of tissue extracts showed that the predominant 14 C residue in liver and kidney was [ 14 C]-3,5,6-trichloro-2-pyridinol (chlorpyridinol) whereas [ 14 C]chlorpyrifos was predominant in fat and heart extracts. In muscle, in addition to approximately equal amounts of [ 14 C]chlorpyridinol and [ 14 C]chlorpyrifos, 18.6% of the radioactivity was unidentified; alkaline hydrolysis quantitatively converted the latter radioactivity to pyridinol

  5. Historical 14C measurements from the Atlantic, Pacific and Indian Oceans. Final report

    International Nuclear Information System (INIS)

    Fairhall, A.W.; Young, A.W.

    Atmospheric nuclear testing produced a dramatic increase in the level of 14 C in atmospheric CO 2 . Since the tropospheric residence time of 14 C is on the order of a few years before being transferred to the sea, it appeared that a study of the distribution of the excess 14 C in the sea and its change with time would give valuable insight into such problems as the rate of CO 2 exchange between the atmosphere and the sea and its dependence on wind speed over the sea surface; the rate of transfer by oceanic mixing processes of contaminants, including fallout radionuclides introduced initially into the mixed surface layer of the sea, into the deep sea; the rate of bottom water formation at high latitudes and subsequent advective transport from these source regions into the deep sea. Therefore a 14 C sampling program was initiated. A method was developed for stripping CO 2 from sea water on board ship. The assay for 14 C was performed by a radiocarbon gas proportional counter. Information on temperature and salinity at the various sampling depths as well as total CO 2 and absolute concentration of 14 C is tabulated

  6. Direct dating of archaeological pottery by compound-specific 14C analysis of preserved lipids.

    Science.gov (United States)

    Stott, Andrew W; Berstan, Robert; Evershed, Richard P; Bronk-Ramsey, Christopher; Hedges, Robert E M; Humm, Martin J

    2003-10-01

    A methodology is described demonstrating the utility of the compound-specific 14C technique as a direct means of dating archaeological pottery. The method uses automated preparative capillary gas chromatography employing wide-bore capillary columns to isolate individual compounds from lipid extracts of archaeological potsherds in high purity (>95%) and amounts (>200 microg) sufficient for radiocarbon dating using accelerator mass spectrometry (AMS). A protocol was developed and tested on n-alkanes and n-carboxylic acids possessing a broad range of 14C ages. Analytical blanks and controls allowed background 14C measurements to be assessed and potential sources of errors to be detected, i.e., contamination with modern or dead 14C, isotopic fraction effects, etc. A "Russian doll" method was developed to transfer isolated target compounds onto tin powder/capsules prior to combustion and AMS analyses. The major advantage of the compound-specific technique is that 14C dates obtained for individual compounds can be directly linked to the commodities processed in the vessels during their use, e.g., animal fats. The compound-specific 14C dating protocol was validated on a suite of ancient pottery whose predicted ages spanned a 5000-year date range. Initial results indicate that meaningful correlations can be obtained between the predicted date of pottery and that of the preserved lipids. These findings constitute an important step forward to the direct dating of archaeological pottery.

  7. Mineralization of 14C-Pirimiphos-Methyl in Soil Under Aerobic and Anaerobic Conditions

    International Nuclear Information System (INIS)

    Zayed, S.M.A.D.; Farghly, M.; El-Maghrby, S.

    2006-01-01

    The mineralization of 14 C-ring labelled pirimiphos-methyl in clay loam soil was determined in a three months laboratory incubation period under anaerobic and aerobic conditions. Evolution of 14 CO2 increased with time and reached 9.2% and 12 %, of the initial 14 C-concentration , within 90 days in case of anaerobic and aerobic conditions, respectively, at that time, soil contained about 61.5% of the applied dose as extractable residues under anaerobic conditions and 59% under aerobic conditions. the unextractable pesticide residues gradually increased with time and the highest binding capacity of about 11%-13% was observed after 90 days of incubation. the total 14 C-activity recovered from soil was generally between 82% and 92% of the applied radiocarbon. the nature of methanolic 14 C-residues was determined by chromatographic analysis and the results revealed the presence of pirimiphos- methyl as a main product together with its phenol. the principle of radio-respirometry has been used for evaluating the effect of different application rates of pirimiphos-methyl on soil microbial activity using U- 14 C-glucose as a substrate. At two concentrations used, pirimiphos-methyl showed an inhibition in the rate of 14 Co2 evolution over 14 days of incubation as a result of oxidation of 14 C-glucose by microorganisms especially in case of high concentration

  8. High sensitivity optical molecular imaging system

    Science.gov (United States)

    An, Yu; Yuan, Gao; Huang, Chao; Jiang, Shixin; Zhang, Peng; Wang, Kun; Tian, Jie

    2018-02-01

    Optical Molecular Imaging (OMI) has the advantages of high sensitivity, low cost and ease of use. By labeling the regions of interest with fluorescent or bioluminescence probes, OMI can noninvasively obtain the distribution of the probes in vivo, which play the key role in cancer research, pharmacokinetics and other biological studies. In preclinical and clinical application, the image depth, resolution and sensitivity are the key factors for researchers to use OMI. In this paper, we report a high sensitivity optical molecular imaging system developed by our group, which can improve the imaging depth in phantom to nearly 5cm, high resolution at 2cm depth, and high image sensitivity. To validate the performance of the system, special designed phantom experiments and weak light detection experiment were implemented. The results shows that cooperated with high performance electron-multiplying charge coupled device (EMCCD) camera, precision design of light path system and high efficient image techniques, our OMI system can simultaneously collect the light-emitted signals generated by fluorescence molecular imaging, bioluminescence imaging, Cherenkov luminance and other optical imaging modality, and observe the internal distribution of light-emitting agents fast and accurately.

  9. Reconstructing the history of 14C discharges from Sellafield. Part 2. Aquatic discharges

    International Nuclear Information System (INIS)

    Cook, G.T.; MacKenzie, A.B.; Naysmith, F.H.; Anderson, R.; Naysmith, P.; Kershaw, P.J.

    2004-01-01

    Prior to 1984, the reported marine 14 C discharges from Sellafield were estimates: 0.2 TBq per annum from 1952 to 1969 and 1 TBq per annum until 1984 when measurements commenced. The relationship between the net excess 14 C activity in annually collected Nori (Porphyra umbilicalis) seaweed samples and the annual discharges (estimated and measured) implies that the discharges were not as constant as the estimates. Based on the relationship between post-1984 measured discharges and the excess 14 C in the seaweed, two simple empirical models were used to re-calculate the discharges between 1967 and 1984. Gamma-spectrometry measurements on the seaweed also indicate that Porphyra is a sensitive indicator of changes in discharge of other radionuclides, brought about by the introduction of new waste clean-up technologies within Sellafield. (author)

  10. Science that connects the past and the future. Fifty years of 14C dating

    International Nuclear Information System (INIS)

    Imamura, M.

    2006-01-01

    Major contribution of radiochemistry in archaeological sciences is the dating which provides the most essential information in studies of prehistory. In particular the method of 14 C dating revolutionized the theory of civilization in the world. In this talk I will review 50 years of 14 C dating, techniques and applications, and then the possibilities in contemporary world. The technical developments are featured by ultra-sensitive method of accelerator mass spectrometry in 1977 and its developments, and an introduction of international calibration datasets for 14 C dates started in 1986. Both contributed greatly to improvements in versatility and precision for dating. As for the applications, several interesting topics are reviewed such as the origin of agriculture and its propagation in the western world, the oldest pottery production in Japanese archipelago and its relation to world climate, paddy-rice agriculture and its propagation in Japanese archipelago. Since 14 C studies in nature is also well known as key information on carbon dynamics in earth's surface, it may be said that 14 C play an extraordinary role in understanding our past, present and the future. (author)

  11. Preparation of D-[U-14C]galactose and α-D-[U-14C]galactose-1-phosphate

    International Nuclear Information System (INIS)

    Kolina, J.; Hromadkova, B.

    1989-01-01

    Optically pure D-[U- 14 C]galactose was prepared on a preparatory scale using the galactokinase enzyme. The suggested procedure allows to also prepare a α-D-[U- 14 C]galactose-1-phosphate and L-[U- 14 ]galactose giving good yield. The experiments proved that the raw fraction isolated from yeast of the Kluyveromyces fragilis strain or the Kluyveromyces lactis strain shows sufficient activity. Phosphorylation of D-[U- 14 C]galactose practically terminates after 30 mins of incubation. DL-[U- 14 C]galactose isolated using preparatory paper chromatography from the acid hydrolyzate of [U- 14 C] polysaccharide is a satisfactory radioactive precursor. The developed preparation procedure theoretically contributed towards the further elucidation of the problem of the proportional representation of galactose stereo-isomers in extracellular polysaccharide isolated from red algae. In this respect data in the literature differ and some sources state a significantly higher propertion of L-galactose. The experiments showed that [U- 14 C] polysaccharide isolated from the red algae Porphyridium cruentum prevalently contains D-[U- 14 C]galactose, which confirms the process of enzyme reaction. (author). 1 tab., 4 refs

  12. Local variance of atmospheric 14C concentrations around Fukushima Dai-ichi Nuclear Power Plant from 2010 to 2012

    DEFF Research Database (Denmark)

    Chen, Biying; Xu, Sheng; Cook, Gordon T.

    2017-01-01

    Radiocarbon (14C) has been measured in single tree ring samples collected from the southwest of the Fukushima Dai-ichi Nuclear Power Plant. Our data indicate south-westwards dispersion of radiocarbon and the highest 14C activity observed so far in the local environment during the 2011 accident....... The abnormally high 14C activity in the late wood of 2011 ring may imply an unknown source of radiocarbon nearby after the accident. The influence of 14C shrank from 30 km during normal reactor operation to 14 km for the accident in the northwest of FDNPP, but remains unclear in the southwest....

  13. Studies on residues of 14C malathion in soils

    International Nuclear Information System (INIS)

    Ghezal, F.; Bennaceur, M.

    1991-04-01

    The extractability, the mobility and formation of bound 14C labelled residues in two soils under normal conditions were investigated with malathion. Comparison is made between irradiated and autoclaved soils. The highest concentration of the product is found in the first section (0-4cm) after experiment. Three compounds were found in the soils. 14C malathion is decomposed to 14C02. The degradation is more important in organic matter rich soil. In rich soil, 50% of 14C product is degradated after 17 days. This percentage is only 10%, for poor soil. The 14CO 2 produced in non-sterile soil is 33,05%. This percentage is respectively 10,92% and 3,57% only for irradiated and autoclaved soils

  14. Determination of phagocytosis in periodontitis postjuvenilis using 14C

    International Nuclear Information System (INIS)

    Zietek, M.

    1990-01-01

    In 20 patients with periodontitis and 10 healthy controls phagocytosis was determined using 14 C-labelled Staphylococcus aureus. The decrease of phagocytosis found in the diseased patients was significant

  15. Forensic applications of {sup 14}C bomb-pulse dating

    Energy Technology Data Exchange (ETDEWEB)

    Zoppi, U. E-mail: ugo@ansto.gov.au; Skopec, Z.; Skopec, J.; Jones, G.; Fink, D.; Hua, Q.; Jacobsen, G.; Tuniz, C.; Williams, A

    2004-08-01

    After a brief review of the basics of {sup 14}C bomb-pulse dating, this paper presents two unique forensic applications. Particular attention is dedicated to the use of the {sup 14}C bomb-pulse to establish the time of harvest of illicit drugs such as heroin and opium. Preliminary measurements of {sup 14}C concentrations in milligram samples taken from seized drugs are presented. {sup 14}C bomb-pulse dating can determine whether drug distribution originates from stockpiles or recent manufacture, and support the action of law enforcement authorities against criminal organisations involved in drug trafficking. In addition, we describe the dating of wine vintages for a number of authenticated single label vintage red wines from the Barossa Valley - South Australia. Our results show that radiocarbon dating can be used to accurately determine wine vintages and therefore reveal the addition of unrelated materials of natural and synthetic origin.

  16. Forensic applications of 14C bomb-pulse dating

    International Nuclear Information System (INIS)

    Zoppi, U.; Skopec, Z.; Skopec, J.; Jones, G.; Fink, D.; Hua, Q.; Jacobsen, G.; Tuniz, C.; Williams, A.

    2004-01-01

    After a brief review of the basics of 14 C bomb-pulse dating, this paper presents two unique forensic applications. Particular attention is dedicated to the use of the 14 C bomb-pulse to establish the time of harvest of illicit drugs such as heroin and opium. Preliminary measurements of 14 C concentrations in milligram samples taken from seized drugs are presented. 14 C bomb-pulse dating can determine whether drug distribution originates from stockpiles or recent manufacture, and support the action of law enforcement authorities against criminal organisations involved in drug trafficking. In addition, we describe the dating of wine vintages for a number of authenticated single label vintage red wines from the Barossa Valley - South Australia. Our results show that radiocarbon dating can be used to accurately determine wine vintages and therefore reveal the addition of unrelated materials of natural and synthetic origin

  17. Synthesis of [14C]-labelled AY-30,068

    International Nuclear Information System (INIS)

    Hicks, D.R.; Hangeland, J.J.; Mobilio, D.; DeLange, B.

    1988-01-01

    [ 14 C]AY-30,068 (cis-1,8-diethyl-2,3,4,9-tetrahydro-4-(2-propenyl)-1H-carbazole-1-acetic acid), a potent analgesic agent, was prepared by incorporating [ 14 C]methyl iodide via a Wittig reaction. The intermediate aldehyde was synthesized in six steps from cis-1-ethyl-2-oxo-4-(2-propenyl)cyclohexaneacetic acid methyl ester. Three batches of the [ 14 C]labelled AY-30,068 were produced, giving a combined overall yield of 9% from [ 14 C]methyl iodide sp. act. 51.2, 17.7 and 4.4 μCi/mg; 97.5, 98.3, and 98.6% radiochemical purity, respectively. (author)

  18. Incorporation of 14C-succinate in Synechococcus

    International Nuclear Information System (INIS)

    Doehler, G.

    1983-01-01

    The cyanobacterium Synechococcus (= Anacystis nidulans) was grown under normal air conditions (0.03 vol.% CO 2 ) and in low white light (0.5 x 10 3 μW/cm 2 ) at 37 0 C. Kinetics of 14 C incorporation into several soluble products and pigments were studied after adding 14 C-succinate during photosynthesis and in the dark using the autoradiographic method. Radioactivity was found mainly in glutamate and aspartate during the photosynthetic period independent on 3-(3',4'-dichlorphenyl)-1,1-dimethylurea preincubation. In the dark period 14 C label could also be detected in malate. Short-term kinetics experiments showed a decrease in 14 C label of glutamate and a parallel increase of aspartate. Results were discussed in respect to the interrupted tricarboxylic acid cycle. (author)

  19. Forensic applications of 14C bomb-pulse dating

    Science.gov (United States)

    Zoppi, U.; Skopec, Z.; Skopec, J.; Jones, G.; Fink, D.; Hua, Q.; Jacobsen, G.; Tuniz, C.; Williams, A.

    2004-08-01

    After a brief review of the basics of 14C bomb-pulse dating, this paper presents two unique forensic applications. Particular attention is dedicated to the use of the 14C bomb-pulse to establish the time of harvest of illicit drugs such as heroin and opium. Preliminary measurements of 14C concentrations in milligram samples taken from seized drugs are presented. 14C bomb-pulse dating can determine whether drug distribution originates from stockpiles or recent manufacture, and support the action of law enforcement authorities against criminal organisations involved in drug trafficking. In addition, we describe the dating of wine vintages for a number of authenticated single label vintage red wines from the Barossa Valley - South Australia. Our results show that radiocarbon dating can be used to accurately determine wine vintages and therefore reveal the addition of unrelated materials of natural and synthetic origin.

  20. Genetic consequences of the 14C-decay

    International Nuclear Information System (INIS)

    Gracheva, L.M.; Korolev, V.G.

    1978-03-01

    There are only few investigations on the biological and genetic consequences of 14 C decay especially due to the long half-life of 14 C. Naturally, the consequences of the decay of 14 C incorperated in DNA is of particular interest. Due to the thus occuring conversion into nitrogen, either opening of the ribose residue ring and base occurs or conversion into base analogue. The present work gives a survey on the investigational results on this topic which were obtained by various authors on phages, bacteria, algae and animal cells, as well as on molecular level. It was shown that the transmutation for the occurence of a lethal effect is many times more effective than β-radiation. Investigations of the mutagenic effects and other genetic effects of the 14 C decay were carried out on micro-organisms, however also on higher forms of life, plants, insects and mice. An analysis of the mutations showed that transitions as well as transversions occur. As example for genetic effects of 14 C decay, the two following are named. In the case of mice which were exposed to 14 CO 2 atmosphere, it was seen that the number of polyptoidal chromosome sets in the first spermotacytes increased considerably, an increase of the chromosome conversion rate was however not observed. When treating gryllus larvae with 14 C, it was interesting to note that the crossing of 14 C-contained females with normal males produced viable eggs, whereas normal females after crossing with 14 C contained males, laid no more eggs. (MG) 891 MG [de

  1. Synthesis and analysis of 14C-labelled butyltin compounds

    International Nuclear Information System (INIS)

    Kloetzer, D.

    1976-01-01

    This paper deals with methods for the synthesis of 14 C-labelled analoga of the important biocides tributyltin oxide, tributyltin benzoate, tributyltin salicylate and tributyltin fluoride as well as dibutyltin oxide. The radioactive starting substance butylbromide-1- 14 C is treated with sodium and monobutyltin chloride or tin tetrachloride to form a mixture of radioactive butyltin compounds from which the substance desired is separated. A system satisfactorily meeting the conditions for thin-layer radiochromatography is presented. (author)

  2. Radioactive decay of 223Ra by 14C emission

    International Nuclear Information System (INIS)

    Yashita, S.; Gregorich, K.; Ghiorso, A.

    1985-01-01

    Recently H.J. Rose and G.A. Jones at the University of Oxford reported the very difficult observation of an exotic radioactive decay mode in 233 Ra, its spontaneous disintegration by the emission of 14 C particles. The authors have confirmed their somewhat surprising discovery by an independent method. Within the present experimental accuracy the magnetic rigidity, energy and branching ratio support the assignment of 14 C emission from 223 Ra as proposed by the Oxford experiment

  3. 14C-Metampicillin stability in several physiological sera

    International Nuclear Information System (INIS)

    Jimeno de Osso, F.; Casas Medica, F.; Carriazo Tovar, D.

    1981-01-01

    Degradation of 14 C -metampicillin incorporated to several physiological sera for medical uses has been studied. Influence of environmental conditions as well as possible interaction with the solvent have been specially analyzed. Degradation level of the labelled multiplication has been determined and its degradation products have been separated by using chromatographic and radiochemical methods. Likewise, the 14 C -metam picill synthesis has been described. Finally, the results obtained have been discussed and evaluated. (Author) 9 refs

  4. Heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Olsen, Jakob Lind

    This thesis present a highly sensitive silicon microreactor and examples of its use in studying catalysis. The experimental setup built for gas handling and temperature control for the microreactor is described. The implementation of LabVIEW interfacing for all the experimental parts makes...

  5. Aluminum nanocantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nanocantilevers using a simple, one mask contact UV lithography technique with lateral and vertical dimensions under 500 and 100 nm, respectively. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Furthermore, it is shown ...

  6. 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

  7. Metabolic patterns of 14C incorporation by selected vascular plants following field incubations with acetate-2-14C in two plant successional stages in Glacier Bay, Alaska

    International Nuclear Information System (INIS)

    Wu, Pei-Hsing Lin

    1975-01-01

    Metabolic patterns of some vascular plants (Dryas sp., Vaccinium sp., Salix sp., Alnus sp., Epilobium sp.), occurring in successional habitats, following acetate-2- 14 C incubations in the field were demonstrated for the first time. Relative radioactivity within the alcoholic soluble fraction of each species reflects its distribution in successional communities. A high level of 14 C-sugars was present in the plants of the pioneer community; on the other hand a high level of 14 C-organic acids was present in the plants of the forest community. Three patterns, based on the relative activities of the sugar- and organic acid-pools were noted which correspond to the range and the frequency of occurrence of each species in the successional stages. Only two types of 14 C-amino acid levels were noted corresponding to the range of distribution. Plants having less than 10% relative radioactivity in amino acid-pools had a limited range of distribution and reside in only one habitat; plants having more than 10% radioactivity showed wider ranges of distribution occurring in at least two habitats. (auth.)

  8. Distribution of 14C after oral administration of [1-14C]linoleic acid in rats fed different levels of essential fatty acids

    International Nuclear Information System (INIS)

    Becker, W.

    1984-01-01

    Rats from an inbred Sprague-Dawley strain were fed semisynthetic diets with a low [0.3 energy percent (en %)], normal (3 en %) or high (10 en %) content of essential fatty acids (EFA) for at least three generations. Twenty-nine- to 33-day-old male rats were given a single intragastric dose of [1-14C]linoleic acid in olive oil, and the respiratory CO2, urine and feces were collected for 46 hours (expt 1) or 20 hours (expt 2). The 14C activity in respiratory CO2, feces, urine and the carcass was determined in both experiments. In experiment 2 it was also measured in samples of the brown fat, liver, adrenals, white fat, skeletal muscles and brain. In both experiments the rats fed the low EFA diet retained significantly more 14C activity than the rats fed the normal or high EFA diets. In all groups the concentration of label was highest in the brown fat and the adrenals, but the above differences among the groups with respect to 14C retention were mainly observed in the liver, skeletal muscles and brain

  9. Tracer experiment administering L-phenylalanine-U-14C and L-tyrosine-U-14C to the tissue slices of bamboo shoots

    International Nuclear Information System (INIS)

    Kozukue, E.; Mizuno, S.

    1987-01-01

    Uniformly 14 C-labeled L-phenylalanine and L-tyrosine were administered to tissue slices of both top and base sections of bamboo shoots. Alcohol soluble substances were extracted and then separated into organic acid, sugar and amino acid fractions by ion exchange chromatography. The homogentisic acid fraction among the organic acids was collected by high-performance liquid chromatography (HPLC) and its radioactivity was measured, while the alcohol insoluble residue was used for the analysis of lignin aldehyde by the method of alkaline nitrobenzene oxidation. 1. The two labeled amino acids were steadily incorporated into the tissues during incubation and rapidly converted to organic acid, sugar and alcohol insoluble residue, especially the latter. 2. On determining the amount of phenylalanine converted to tyrosine, it was found that this was extremely small. 3. The incorporation of phenylalanine-U- 14 C into alcohol insoluble residue was higher than that of tyrosine in both sections. 4. Although the conversion into lignin aldehyde from phenylalanine-U- 14 C was higher than that from tyrosine-U- 14 C, it was found that tyrosine incorporated into the shoots was converted to a remarkable extent for formation of lignin aldehyde. 5. The incorporation of phenylalanine and tyrosine into homogentisic acid was very low. From these results, we assume that the conversion of phenylalanine to tyrosine or of tyrosine to homogentisic acid is very small, and that a part of the high amount of tyrosine in the shoots may be used for formation of lignin

  10. Analysis of 14C-bearing compounds released by the corrosion of irradiated steel using accelerator mass spectrometry.

    Science.gov (United States)

    Cvetković, B Z; Salazar, G; Kunz, D; Szidat, S; Wieland, E

    2018-06-25

    The combination of ion chromatography (IC) with accelerator mass spectrometry (AMS) was developed to determine the speciation of 14C-(radiocarbon) bearing organic compounds in the femto to pico molar concentration range. The development of this compound-specific radiocarbon analysis (CSRA) of carboxylic acids is reported and the application of the method on a leaching solution from neutron-irradiated steel is demonstrated. The background and the dynamic range of the AMS-based method were quantified. On using 14C-labelled standards, the measurements demonstrate the repeatability of the analytical method and the reproducible recovery of the main target carboxylic acids (i.e., acetate, formate, malonate, and oxalate). The detection limit was determined to be in the mid fmol 14C per L level while the dynamic range of the analytical method covers three orders of magnitude from the low fmol to the mid pmol 14C per L level. Cross contamination was found to be negligible during IC fractionation and was accounted for during eluate processing and 14C detection by AMS. The 14C-bearing carboxylates released from an irradiated steel nut into an alkaline leaching solution were analysed using the CSRA-based analytical method with the aim to check the applicability of the approach and develop appropriate sample preparation. The concentrations of 14C-bearing formate and acetate, the main organic corrosion products, were at a low pmol 14C per L level for convenient dimensions of the alkaline leaching experiment which demonstrates that compound-specific 14C AMS is an extremely sensitive analytical method for analysing 14C-bearing compounds. The content of total organic 14C in solution (TO14C) determined by the direct measurement of an aliquot of the leaching solution agrees well with the sum of the 14C concentrations of the individual carboxylates within the uncertainty of the data. Furthermore, the TO14C content is in good agreement with the calculated value using the corrosion rate

  11. Single photon detector with high polarization sensitivity.

    Science.gov (United States)

    Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

    2015-04-15

    Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared.

  12. Current /sup 14/C methods for measuring primary production: gross underestimates in oceanic waters

    Energy Technology Data Exchange (ETDEWEB)

    Gieskes, W W.C.; Kraay, G W; Baars, M A [Netherlands Institute for Sea Research, Texel, Netherlands

    1979-10-01

    The amount of organic matter produced through autotrophic processes in the euphotic zone of the tropical open ocean and available for respiration of autotrophs and heterotrophs was at least 5 to 15 times higher than values derived from the common /sup 14/C method suggested. The new estimates are based on measurements of /sup 14/C incorporation in organic matter of ocean samples incubated in bottles of up to 4 litres. Oceanic phytoplankton appeared to have a high growth rate, with generation times of hours, not days. High heterotrophic activity, finding its expression in high dark fixation rates of /sup 14/C, took place in conjunction with this high primary production of organic matter.

  13. 14C emission from Swedish nuclear power plants and its effect on the 14C levels in the environment

    International Nuclear Information System (INIS)

    Stenstroem, K.; Erlandsson, Bengt; Hellborg, R.; Kiisk, M.; Persson, Per; Mattsson, Soeren; Thornberg, C.; Skog, G.

    2000-02-01

    The radionuclide 14 C is produced in all types of nuclear reactors mainly by neutron induced reactions in oxygen ( 17 O), nitrogen ( 14 N) and carbon ( 13 C). Part of the 14 C created is continuously released during normal operation as airborne effluents in various chemical forms (such as CO 2 , CO and hydrocarbons) to the surroundings. Because of the biological importance of carbon and the long physical half-life of 14 C, it is of interest to measure the releases and their incorporation into living material. The 14 C activity concentrations in annual tree rings and air around two Swedish nuclear power plants (Barsebaeck and Forsmark) as well as the background 14 C activity levels from two reference sites in southern Sweden during 1973-1996 are presented in this report. In order to verify the reliability of the method some investigations have been conducted at two foreign nuclear sites, Sellafield fuel reprocessing plant in England, and Pickering nuclear generating station in Canada, where the releases of 14 C are known to be substantial. Furthermore, results from some measurements in the vicinity of Paldiski submarine training centre in Estonia are presented. The results of the 14 C measurements of air, vegetation and annual tree rings around the two Swedish nuclear power plants show very low enhancements of 14 C, if at all above the uncertainty of the measurements. Even if the accuracy of the measurements of the annual tree rings is rather good (1-2%) the contribution of 14 C from the reactors to the environment is so small that it is difficult to separate it from the prevailing background levels of 14 C . This is the case for all sampling procedures: in air and vegetation as well as in annual tree rings. Only on a few occasions an actual increase is observed. However, although the calculations suffer from rather large uncertainties, the calculated release rate from Barsebaeck is in fair agreement with reported release data. The results of this investigation show

  14. Highly sensitive microcalorimeters for radiation research

    International Nuclear Information System (INIS)

    Avaev, V.N.; Demchuk, B.N.; Ioffe, L.A.; Efimov, E.P.

    1984-01-01

    Calorimetry is used in research at various types of nuclear-physics installations to obtain information on the quantitative and qualitative composition of ionizing radiation in a reactor core and in the surrounding layers of the biological shield. In this paper, the authors examine the characteristics of highly sensitive microcalorimeters with modular semiconductor heat pickups designed for operation in reactor channels. The microcalorimeters have a thin-walled aluminum housing on whose inner surface modular heat pickups are placed radially as shown here. The results of measurements of the temperature dependence of the sensitivity of the microcalorimeters are shown. The results of measuring the sensitivity of a PMK-2 microcalorimeter assembly as a function of integrated neutron flux for three energy intervals and the adsorbed gamma energy are shown. In order to study specimens with different shapes and sizes, microcalorimeters with chambers in the form of cylinders and a parallelepiped were built and tested

  15. Synthesis of [21-14C]-fusarin C by enzymic demethylation and remethylation with [14C]-diazomethane

    International Nuclear Information System (INIS)

    Lu, S.-J.; Li, M.H.

    1989-01-01

    Fusarin C, a potent mutagen isolated from Fusarium moniliforme culture extracts, has been prepared radiolabeled in two steps by enzymic hydrolysis of the 21-methyl ester group, using phenobarbital induced microsomal preparations, followed by remethylation using [ 14 F]-diazomethane. Yields, based upon fusarin C, were essentially quantitative and approximately 10% of the [ 14 C]-methyl-nitrosourea, converted to diazomethane, reacted to yield [ 14 C]-fusarin C. (author)

  16. High blood pressure and visual sensitivity

    Science.gov (United States)

    Eisner, Alvin; Samples, John R.

    2003-09-01

    The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

  17. Prevalence of Helicobacter Pylori in gastric cancer in a south-east Asian population by 14C-urea breath test

    International Nuclear Information System (INIS)

    Chung, A.Y-F; Chow, P.K.H.; Yu, W-K.; Ho, J.M.S.; Chan, H-S.; Wong, W-K.; Soo, K-C.

    2001-01-01

    Helicobacter pylori is believed to play an important role in the aetiology of gastric cancer. There is a great variability in seropositivity and histological frequency of H. pylori in gastric cancer. The present prospective study investigates the prevalence of H. pylori infection in gastric cancer patients using 14C-urea breath testing. Patients with endoscopic biopsy-proven gastric cancer were fasted for 6 h prior to ingesting 18.5 x 104 Bq of 14C-urea cocktail orally. Breath samples were collected after 20 min by AS/King them to blow into a hyamine solution and measurements were read in a scintillation counter. Fifty out of 51 patients (98%) with gastric cancer were positive on the 14C-urea breath test compared to 29 patients (61%) who were positive on histology. There was no association between sex, age or tumour site, stage, differentiation, Lauren type and H. pylori status. The test was negative in one patient with cardiac tumour in which histology of the resected specimen was also negative for the bacteria. Active H. pylori infection is highly prevalent in gastric cancer in a South-East Asian population. The 14C-urea breath test is a highly sensitive method for detecting the presence of H. pylori even in gastric adenocarcinoma irrespective of the stage

  18. 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.

  19. Characterization of 14C in Swedish light water reactors.

    Science.gov (United States)

    Magnusson, Asa; Aronsson, Per-Olof; Lundgren, Klas; Stenström, Kristina

    2008-08-01

    This paper presents the results of a 4-y investigation of 14C in different waste streams of both boiling water reactors (BWRs) and pressurized water reactors (PWRs). Due to the potential impact of 14C on human health, minimizing waste and releases from the nuclear power industry is of considerable interest. The experimental data and conclusions may be implemented to select appropriate waste management strategies and practices at reactor units and disposal facilities. Organic and inorganic 14C in spent ion exchange resins, process water systems, ejector off-gas and replaced steam generator tubes were analyzed using a recently developed extraction method. Separate analysis of the chemical species is of importance in order to model and predict the fate of 14C within process systems as well as in dose calculations for disposal facilities. By combining the results of this investigation with newly calculated production rates, mass balance assessments were made of the 14C originating from production in the coolant. Of the 14C formed in the coolant of BWRs, 0.6-0.8% was found to be accumulated in the ion exchange resins (core-specific production rate in the coolant of a 2,500 MWth BWR calculated to be 580 GBq GW(e)(-1) y(-1)). The corresponding value for PWRs was 6-10% (production rate in a 2,775 MWth PWR calculated to be 350 GBq GW(e)(-1) y(-1)). The 14C released with liquid discharges was found to be insignificant, constituting less than 0.5% of the production in the coolant. The stack releases, routinely measured at the power plants, were found to correspond to 60-155% of the calculated coolant production, with large variations between the BWR units.

  20. Charged particle reaction studies on /sup 14/C. [Spectroscopic factors

    Energy Technology Data Exchange (ETDEWEB)

    Cecil, F E; Shepard, J R; Anderson, R E; Peterson, R J; Kaczkowski, P [Colorado Univ., Boulder (USA). Nuclear Physics Lab.

    1975-12-22

    The reactions /sup 14/C(p,d), (d,d') and (d,p) have been measured for E/sub p/ = 27 MeV and E/sub d/ = 17 MeV. The (d,d') and (d,p) reactions were studied between theta/sub lab/ = 15/sup 0/ and 85/sup 0/; the (p,d) reactions, between theta/sub lab/ = 5/sup 0/ and 40/sup 0/. The /sup 14/C deformation parameters were deduced from the deuteron inelastic scattering and found to agree with deformations measured in nearby doubly even nuclei. The spectroscopic factors deduced from the (p,d) reaction allowed a /sup 14/C ground-state wave function to be deduced which compares favorably with a theoretically deduced wave function. The (p,d) and (d,p) spectroscopic factors are consistent. The implications of our /sup 14/C ground-state wave function regarding the problem of the /sup 14/C hindered beta decay are discussed.

  1. Low Cost, Low Power, High Sensitivity Magnetometer

    Science.gov (United States)

    2008-12-01

    which are used to measure the small magnetic signals from brain. Other types of vector magnetometers are fluxgate , coil based, and magnetoresistance...concentrator with the magnetometer currently used in Army multimodal sensor systems, the Brown fluxgate . One sees the MEMS fluxgate magnetometer is...Guedes, A.; et al., 2008: Hybrid - LOW COST, LOW POWER, HIGH SENSITIVITY MAGNETOMETER A.S. Edelstein*, James E. Burnette, Greg A. Fischer, M.G

  2. Metabolism and disposition of [14C]-methylcyclosiloxanes in rats.

    Science.gov (United States)

    Domoradzki, Jeanne Y; Sushynski, Christopher M; Sushynski, Jacob M; McNett, Debra A; Van Landingham, Cynthia; Plotzke, Kathleen P

    2017-10-20

    Octamethylcyclotetrasiloxane (D 4 ) and decamethylcyclopentasiloxane (D 5 ) are low molecular weight cyclic volatile methyl siloxanes (cVMSs) primarily used as intermediates or monomers in the production of high molecular weight silicone polymers. The use of D 4 as a direct ingredient in personal care products has declined significantly over the past 20 years, although it may be present as a residual impurity in a variety of consumer products. D 5 is still used as an intentional ingredient in cosmetics, consumer products and in dry cleaning. Persons who may be exposed include occupational exposure for workers, and potential inhalation or dermal exposure for consumers and the general public. Because of the diverse use, especially of D 5 , and the potential for human exposure, a comprehensive program was undertaken to understand the kinetics, metabolism, enzyme induction and toxicity of D 4 and D 5 in rats following relevant routes of exposure. Physiologically based pharmacokinetic (PBPK) models utilizing these studies have been reported for D 4 and D 5 in the rat and human following dermal and inhalation exposures, with the oral uptake component of the model being limited in its description. Data from high dose oral studies in corn oil and simethicone vehicles and neat were used in the D 4 /D 5 harmonized PBPK model development. It was uncertain if the inability to adequately describe the oral uptake was due to unrealistic high doses or unique aspects of the chemistry of D 4 /D 5. Low dose studies were used to provide data to refine the description of oral uptake in the model by exploring the dose dependency and the impact of a more realistic food-like vehicle. Absorption, distribution, metabolism and elimination (ADME) of D 4 and D 5 was determined following a single low oral gavage dose of 14 C-D 4 and 14 C-D 5 at 30 and 100mg/kg body weight (bw), respectively, in a rodent liquid diet. Comparison of the low vs. high dose oral gavage administration of D 4 and D 5

  3. Persistence of 14C maneb in lettuce plants an soil

    International Nuclear Information System (INIS)

    Bennaceur, M.; Sennaoui, Z.; Meguenni, H.

    1992-10-01

    Maneb residue is studied on lettuce plant and soil after spraying on greenhouse with 14C maneb. The residues declined with time. After 37 days from the application, 14C maneb residues in water extracts declined to 1,5. 10-2ug/g from 5,8. 10-1ug/g of the zero day sample in lettuce plants and 4,6. 10-3ug/g from 1,73. 10-1ug/g in soil. The 14C internals residues in lettuce and soil increase respectively till 16 days and 24 days, then decrease to 88% and 4,05% after 37 days. ETU was present in lettuce plant after 8 days then decreases with time. Two metabolites were identified by TLC (EU,ETU)

  4. Temporal distribution of bomb 14C in a forest soil

    International Nuclear Information System (INIS)

    Harkness, D.D.; Harrison, A.F.; Bacon, P.J.

    1986-01-01

    Patterns of 14 C enrichment in the superficial plant debris and mineral soil horizons of an established woodland have been monitored at regular intervals during the past 15 years. These data are compared with a model evaluation of carbon turnover based on the recorded changes in atmospheric 14 C concentration since AD 1900. Leaf litter and decomposing plant debris are characterized by steady-state turnover values of ca 2 and ca 8 years, respectively. A two-component system of fast (≤20 yr) and slow (ca 350 yr) cycling carbon is indicated for the surface (0-5cm) soil humus; below 10cm, the fast component is rare ( 14 C to the soil carbon pool

  5. Atmospheric 14C changes resulting from fossil fuel CO2 release and cosmic ray flux variability

    International Nuclear Information System (INIS)

    Stuiver, M.; Quay, P.D.

    1981-01-01

    A high-precision tree-ring record of the atmospheric 14 C levels between 1820 and 1954 is presented. Good agreement is obtained between measured and model calculated 19th and 20th century atmospheric δ 14 C levels when both fossil fuel CO 2 release and predicted natural variations in 14 C production are taken into account. The best fit is obtained by using a box-diffusion model with an oceanic eddy diffusion coefficient of 3 cm 2 /s, a CO 2 atmosphere-ocean gas exchange rate of 21 moles msup(-2) yrsup(-1) and biospheric residence time of 60 years. For trees in the state of Washington the measured 1949-1951 atmospheric δ 14 C level was 20.0 +- 1.2per mille below the 1855-1864 level. Model calculations indicate that in 1950 industrial CO 2 emissions are responsible for at least 85% of the δ 14 C decline, whereas natural variability accounts for the remaining 15%. (orig.)

  6. AMS of {sup 14}C at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Suter, M.; Huber, R.; Jacob, S. [ETHZ, Zurich (Switzerland); Synal, H.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    At the ETH/PSI AMS facility {sup 14}C test measurements have been performed at low terminal voltages of 0.5 and 1 MV in order to study the feasibility of AMS with very small accelerators. These experiments have demonstrated that interfering molecules ({sup 13}CH and {sup 12}CH{sub 2}) in charge states 1{sup +} and 2{sup +} can be destroyed in an adequate Ar gas stripper. These new results imply the feasibility of a new generation of very small accelerator systems for {sup 14}C. (author) 1 fig., 3 refs.

  7. A new 14C AMS facility at IUAC, New Delhi

    International Nuclear Information System (INIS)

    Kumar, Pankaj; Ojha, S.; Sharma, R.; Gargari, S.; Joshi, R.; Chopra, S.; Kanjilal, D.

    2015-01-01

    A new state of art Accelerator Mass Spectrometry (AMS) facility for 14 C has been developed at IUAC. This facility is based on the 0.5 MV Pelletron accelerator and an Automated Graphitization Equipment (AGE). In addition to the 14 C measurements, this system has the capability to perform 10 Be and 26 AI measurements also. The system is called XCAMS i.e., Compact, Accelerator Mass Spectrometer eXtended for 10 Be and 26 AI. A detailed description of the newly developed AMS facility and the recent measurements will be discussed

  8. The 14C-urea breath-test for the detection of gastric Campylobacter pylori infection

    International Nuclear Information System (INIS)

    Surveyor, I.; Goodwin, C.S.; Mullan, B.P.; Geelhoed, E.; Warren, J.R.; Murray, R.N.; Waters, T.E.; Sanderson, C.R.

    1989-01-01

    Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of 14 C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of 14 C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of 14 C-urea in 24 patients with negative microbiological results was 6.9±4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and 14 C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the 14 C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab

  9. Effect of tolbutamide on 14C-sodium bicarbonate and 14C-alanine metabolism in isolated rat hepatocytes

    International Nuclear Information System (INIS)

    Kunjathoor, V.V.; Ye, Y.; Pillai, U.A.; Ferguson, P.W.; Medon, P.J.

    1990-01-01

    Tolbutamide (TOLB) is a sulfonylurea commonly used in the treatment of noninsulin-dependent diabetes mellitus. Studies have shown that TOLB affects gluconeogenesis and glycolysis from various substrates in the liver. Specifically, TOLB inhibits gluconeogenesis from lactate in a dose-dependent manner. In order to further clarify tolbutamide's mechanism of action, its effect on the incorporation of 14 C from NaH 14 CO 3 and 14 C-alanine into glucose, lactate or pyruvate in the presence of lactate was measured. Rat hepatocytes were incubated with lactate (2.0 mM) with or without TOLB (1.0 mM) in the presence of NaH 14 CO 3 or 14 C-alanine. TOLB inhibited the incorporation of C 14 from NaHCO 3 and alanine into glucose by 55 and 56%, respectively. TOLB did not alter the incorporation of C 14 from NaHCO 3 into lactate or pyruvate. TOLB did not affect the incorporation of 14 C from alanine into lactate but produced a pooling of 14 C as pyruvate. The authors data support studies demonstrating the TOLB produces its actions, in part, by increasing the concentration of fructose-2,6-bisphosphate and inhibiting pyruvate carboxylase

  10. Effect of commercial processing procedures on 14C-LINDANE residues in corn oil

    International Nuclear Information System (INIS)

    Soliman, S.M.

    2006-01-01

    At blooming, maize plants were sprayed twice, 23 days apart, at a dose of 22 mg equivalent to 5 μCi/ plant. At post harvest, maize seeds had a radioactivity corresponding to 0.36% of the applied dose. The insecticide residues in crude oil, cake and methanolic extract were amounted to 8 % and 60 % 5 % , respectively, of original residues inside the seeds.The 14 C-activity in the crude oil could be reduced by commercial processes locally used for refining. The refined oil had a residue level of about 0.7 ppm mainly in the form of unchanged lindane in addition to a number of chloro phenols as main metabolites. Refining of corn oil fortified with 14 C-lindane led to a high reduction of 14 C-lindane (88%). The refined oil contained a residue consisting lindane and its chloro phenols

  11. Production and uses of 14C-labelled rice straw in organic matter decomposition studies

    International Nuclear Information System (INIS)

    Capistrano, R.F.; Neue, H.N.U.

    1987-01-01

    A new systematic procedure in labeling rice homogenously with 14 CO 2 to maturity is described. It uses a modified plant growth chamber equipped with provisions for the growth requirements of rice as well as, the decontamination and safety aspects of labeling process. Uses of 14 C-labeled rice straw are described. Sample preparation using a new wet combustion set-up a high vacuum preparation line, concomitant with instruments as liquid scintillation counter, vibrating reed electrometer and radiogaschromatograph is also discussed. The turnover and behavior of 14 C-labeled rice straw in organic matter decomposition experiments on wetland soils, upland soils, greenhouse set-up and controlled laboratory conditions are concurrent researches that make use of the produced 14 C-labeled straw. Initial results are discussed. (Auth.) 16 refs.; 14 figs.; 2 tabs

  12. Validation of 14 C-urea breath test for diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Mattar, Rejane; Silva, Fernando Marcuz; Alexandrino, Ana Maria; Laudanna, Antonio Atilio

    1999-01-01

    The aim of this study was to validate the 14 C-urea breath test for use in diagnosis of Helicobacter pylori infection. Thirty H. pylori positive patients, based on histologic test and thirty H. pylori negative patients by histology and anti-H pylori IgG entered the study. Fasting patients drank 5 uCi of 14 C-urea in 20 ml of water. Breath samples were collected at O, 5, 10, 15, 20 and 30 min. The difference of cpm values between the two groups was significant at all the time intervals, besides time 0 (p 14 C-urea breath test is highly accurate for Helicobacter pylori diagnosis. It is fast, simple and should be the non-invasive test used after treating Helicobacter pylori infection. (author)

  13. Plant for retention of 14C in reprocessing plants for LWR fuel elements

    International Nuclear Information System (INIS)

    Braun, H.; Gutowski, H.; Bonka, H.; Gruendler, D.

    1983-01-01

    The 14 C produced from nuclear power plants is actually totally emitted from nuclear power plants and reprocessing plants. Using the radiation protection principles proposed in ICRP 26, 14 C should be retained at heavy water moderated reactors and reprocessing plants due to a cost-benefit analysis. In the frame of a research work to cost-benefit analysis, which was sponsored by the Federal Minister of the Interior, an industrial plant for 14 C retention at reprocessing plants for LWR fuel elements has been planned according to the double alkali process. The double alkali process has been chosen because of the sufficient operation experience in the conventional chemical technique. In order to verify some operational parameters and to gain experiences, a cold test plant was constructed. The experiment results showed that the double alkali process is a technically suitable method with high operation security. Solidifying CaCO 3 with cement gives a product fit for final disposal

  14. Fate of 14 C Labelled fungicides maneb and mancozeb during processing of contaminated soybean oil

    International Nuclear Information System (INIS)

    Zayed, S.M.A.D.; Hegazi, B.

    1991-01-01

    Soybeans from plants previously treated with 14 C-maneb and 14 C-mancozeb contain 0.62% and 3.15% of the applied dose, respectively. Crude soybean soil extracted from seeds was subjected to different refining processes. The effect of commercial refining processes, namely: alkali treatment, bleacking, winterization and deoderization on the nature and magnitude of the original residues was investigated. A high percentage of the residues was eliminated by alkali refining and deoderization processes. Analysis of residues after each step showed the ETU, ETM and ETD, in addition to two unknowns where the main 14 C-residues present in the oil. The refined oil contains around 1% of the residues originally present in the crude soybean oil.4 tab

  15. Characterization of {sup 14}C in neutron irradiated NBG-25 nuclear graphite

    Energy Technology Data Exchange (ETDEWEB)

    LaBrier, Daniel, E-mail: labrdani@isu.edu; Dunzik-Gougar, Mary Lou

    2014-05-01

    Recent studies suggest that the highest concentration of {sup 14}C contamination present in reactor-irradiated graphite exists on the surfaces and within near-surface layers. Surface-sensitive analysis techniques (XPS, ToF-SIMS, SEM/EDS and Raman) were employed to determine the chemical nature of {sup 14}C on irradiated NBG-25 (nuclear grade) graphite surfaces. Several {sup 14}C precursor species are identified on the surfaces of irradiated NBG-25; the quantities of these species decrease at sub-surface depths, which further suggests that {sup 14}C formation is predominantly a surface-concentrated phenomenon. The elevated presence of several surface oxide complexes on irradiated NBG-25 surfaces are attributed directly to neutron irradiation. Larger numbers of oxide bonds were found on irradiated NBG-25 surfaces (when compared to unirradiated samples) in the form of interlattice (e.g. ether) and dangling (e.g. carboxylate and ketone) bonds; the quantities of these bond types also decrease with increasing sub-surface depths.

  16. Microdose 14C urea breath test for the diagnosis of Helicobacter pylori: a survey in Iranian population

    Directory of Open Access Journals (Sweden)

    Reza Dowlatabadi Bazaz

    2005-01-01

    Full Text Available The carbon -14 urea breath test (UBTis a non-invasive and simple method for the diagnosis of Helicobacter pylori infection. Attempts have been made to use lower doses of 14C-urea in the UBT in order to reduce the radiation risk of the test. The aim of this study was to assess the accuracy of a microdose (1 µCi [37 KBq] 14C-UBT in Iranian population for validation of its diagnostic accuracy against gold standard methods. Eighty and two patients were subjected to upper gastrointestinal endoscopy as well as 14C-UBT in one week. Rapid urease test and histological examinations were used as gold standard. Breath samples were collected 10, 20 and 30 minute after ingestion of 1 µCi of 14C- urea solution and their activities were measured using a scintillation counter and expressed as counts per minute (cpm and disintegration per minute (dpm. Good agreement was observed between the 14C-UBT and gold standard for samples which were collected 20 minutes after 14C-urea administration. The 14CUBT showed 100% sensitivity, 95% specificity, 95.45% positive predictive value, 100% negative predictive value and 97.50% accuracy. The results of this study showed good concordance between the 14C-UBT and invasive methods.

  17. Synthesis of 14C labelled lidocaine (α-diethylamino acet-2,6-dimethylanilide)

    International Nuclear Information System (INIS)

    Zhou Zhentang; Qian Guojun; Lin Fenzhi; Zhuang Daoling; Zhang Yulong; He Zhanjun

    2002-01-01

    14 C-lidocaine was composed by 14 C-diethylamine reaction with ω-chloroacetic-2,6-dimethylaniline. 14 C-diethylamine was prepared from Ba 14 CO 3 via K 14 CN and 14 C-acetonitrile which was hydrogenated. Radiochemical purity of 14 C-diethylamine and 14 C-lidocaine is >99% by HPLC and TLC respectively. 14 C-lidocaine is needed for breath assay of mouse for measuring liver function

  18. Direct preparation of 14C-labelled 5-allyl- and 5-propyl-2'-deoxyuridine from [2-14C]2'-deoxyuridine

    International Nuclear Information System (INIS)

    Ruth, J.L.; White, S.K.; Bergstrom, D.E.

    1982-01-01

    [2- 14 C]5-Allyl-2'-deoxyuridine was synthesized directly from [2- 14 C]2'-deoxyuridine using mercury, palladium, and 3-chloropropene. [2- 14 C]5-Propyl-2'-deoxyuridine was obtained by hydrogenation of the [ 14 C]5-allyl-2'-deoxyuridine. Advantages of the synthetic method and its application to the preparation of other radiolabeled 5-alkyl/alkenyl-2'-deoxyuridines are discussed. (author)

  19. Measuring techniques for environmental sup 3 H, sup 14 C and sup 222 Rn by liquid scintillation counter

    Energy Technology Data Exchange (ETDEWEB)

    Takata, Shigeru; Saito, Masaaki (Tokyo Metropolitan Isotope Research Center (Japan))

    1991-02-01

    Measuring techniques for environmental {sup 3}H, {sup 14}C and {sup 222}Rn with a liquid scintillation counter have been studied. {sup 3}H in environmental water was enriched by electrolysis and measured with a low background liquid scintillation counter. By this technique, {sup 3}H concentration of ground water, river water, sea water and rain water at Tokyo was founded to be 0.1 {approx} 2.5 Bq/1. {sup 14}C in taurine and ethyl-alcohol was measured directly liquid scintillation counter. By this {sup 14}C measuring, natural products, contain low level {sup 14}C, were distinguished from synthesised products contain no {sup 14}C. {sup 222}Rn in toluene extracted from environmental water or air was measured by scintillation pulse interval analysis method. By this technique, {sup 222}Rn was able to be measured under very low background counting rate, 0.03cpm, and high efficiency. (author).

  20. Apportioning bacterial carbon source utilization in soil using 14 C isotope analysis of FISH-targeted bacterial populations sorted by fluorescence activated cell sorting (FACS): 14 C-FISH-FACS.

    Science.gov (United States)

    Gougoulias, Christos; Meade, Andrew; Shaw, Liz J

    2018-02-19

    An unresolved need in microbial ecology is methodology to enable quantitative analysis of in situ microbial substrate carbon use at the population level. Here, we evaluated if a novel combination of radiocarbon-labelled substrate tracing, fluorescence in situ hybridisation (FISH) and fluorescence-activated cell sorting (FACS) to sort the FISH-targeted population for quantification of incorporated radioactivity ( 14 C-FISH-FACS) can address this need. Our test scenario used FISH probe PSE1284 targeting Pseudomonas spp. (and some Burkholderia spp.) and salicylic acid added to rhizosphere soil. We examined salicylic acid- 14 C fate (mineralized, cell-incorporated, extractable and non-extractable) and mass balance (0-24 h) and show that the PSE1284 population captured ∼ 50% of the Nycodenz extracted biomass 14 C. Analysis of the taxonomic distribution of the salicylic acid biodegradation trait suggested that PSE1284 population success was not due to conservation of this trait but due to competitiveness for the added carbon. Adding 50KBq of 14 C sample -1 enabled detection of 14 C in the sorted population at ∼ 60-600 times background; a sensitivity which demonstrates potential extension to analysis of rarer/less active populations. Given its sensitivity and compatibility with obtaining a C mass balance, 14 C-FISH-FACS allows quantitative dissection of C flow within the microbial biomass that has hitherto not been achieved. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. Mineralization of 14C-labeled agrochemicals in soil

    International Nuclear Information System (INIS)

    Xu Bujin; Huang Xiaohua; Hu Xiuqing; Zhang Yongxi

    2001-01-01

    14 C-labeled compounds were used to study the mineralization of methamidophos, 2,4-D and metsulfuron in soil. Mineralization rate was influenced by the type of soil, concentration of chemical in the soil, the initial soil microbial population and the nature of the chemical. (author)

  2. Method of preparing (U-14C)-D-galactose

    International Nuclear Information System (INIS)

    Zemek, J.; Kucar, S.; Kolina, J.

    1982-01-01

    Whole Chlorella algae cells cultivated in a 14 CO 2 medium were subjected to a β-galactosidase solution buffered to pH=4.5 to 6.0. The produced (U- 14 C)-D-galactose is separated by paper chromatography. (E.S.)

  3. Process for the production of 14C-labelled compounds

    International Nuclear Information System (INIS)

    Oldham, K.G.; Carr, N.G.

    1978-01-01

    The patent describes the production of 14 C-labelled compounds from solution with the aid of algae. A microorganism of the Anacystic species is used, preferably Anacystis nidulans which is also known as 'Indiana 625'. The experiments and their results are described in detail. (UWI) [de

  4. 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

  5. Plasma kinetics of 14C-uric acid in bulls

    International Nuclear Information System (INIS)

    Cetinkaya, N.

    1999-01-01

    Plasma kinetics of uric acid were followed by 14C labelled uric acid to measure the effects of feed intake upon kinetic parameters. Two bulls (average L W 346±79 kg) were given an intravenous administration of a tracer (8-14C-uric acid, 250μCi/50 ml) by single injection via a jugular catheter. Animals were fed a mixed diet containing 30% wheat straw and 70% compounded feed as 95 and 60 % of the voluntary intake. Voluntary intakes were 8 kg/d as fed for two bulls. Blood samples, were collected at 0, 0.5,1, 2, 3, 4, 6, 8, 12, 16, 24 and 28 h after tracer administration. Fractional rates of clearance from the blood and pool size of compartments in the blood were estimated using plasma 8-14C-counts, following the method proposed by Chen and Franklin. The mean values of fractional rates (K 2,1 , K 1,2 ) and compartments pool size (V 1 , V 2 ) and the total pool size of compartments I and 2 at 60% and 95% feeding level were 1.97 and 1.44, 1.06 and 0.78; 76.9 L and 94.5 L, 137.01 L and 163.51 L; 214.0 L and 250.3 L respectively. Plasma kinetic parameters of 14C-uric acid were not affected at different feed intakes

  6. Photosynthetic incorporation of 14C by Stevia rebaudiana

    International Nuclear Information System (INIS)

    Ferraresi, M. de L.; Ferraresi Filho, O.; Bracht, A.

    1985-01-01

    The photosynthetic incorporation of 14 by Stevia rebaudiana specimens was investigated. The 14 C incorporation, when the isotope was furnished to the plant in form of 14 CO 2 , was rapid. After 24 hours, the radioactivity has been incorporated into a great number of compounds including pigments, terpenes, glucose, cellulose and also stevioside and its derivatives. (M.A.C.) [pt

  7. Modified synthesis of 11-[{sup 14}C]-clozapine

    Energy Technology Data Exchange (ETDEWEB)

    Matloubi, Hojatollah E-mail: hmatloubi@seai.neda.net.ir; Ghandi, Mehdi; Zarrindast, M.-R.; Saemian, Nader

    2001-11-01

    The reported synthetic pathway of 8-chloro-11-(4-methyl-1-piperazinyl)-11-[{sup 14}C]-5H-dibenzo[b,e][1,4]diazapine (clozapine) was modified in several steps. The synthetic pathway was shortened by 60% and the total yield was increased from 6% to 23%.

  8. Modified synthesis of 11-[14C]-clozapine

    International Nuclear Information System (INIS)

    Matloubi, Hojatollah; Ghandi, Mehdi; Zarrindast, M.-R.; Saemian, Nader

    2001-01-01

    The reported synthetic pathway of 8-chloro-11-(4-methyl-1-piperazinyl)-11-[ 14 C]-5H-dibenzo[b,e][1,4]diazapine (clozapine) was modified in several steps. The synthetic pathway was shortened by 60% and the total yield was increased from 6% to 23%

  9. Physical Research Laboratory radiocarbon 14C dates : CS-I

    International Nuclear Information System (INIS)

    Agrawal, D.P.; Krishnamurthy, R.V.; Kusumgar, Sheela; Pant, R.K.

    1978-01-01

    The 14 C dates of archaeological samples measured at the Radiocarbon Laboratory of the Physical Research Laboratory, Ahmedabad are presented. Samples were converted into methane and measured in gas proportional counters. Ninety-five percent activity of NBS oxalic acid was used as modern standard. The dates in years B.P. are given for each sample based on the half-life values of 5568 +- 30 years and 5730 +- 40 years, the latter within parenthesis. The dates are not calibrated for 14 C/ 12 C variations. To convert the dates into AD/BC scale, 1950 AD should be used as reference year. A number of 14 C dates (PRL-81, -83, -67, -68) now confirm that the Painted Grey Ware culture extended upto the 3rd century BC. Some of the dates from Barkhera (PRL-113), Bateshwar (PRL-200), Bhimbetka (PRL-17) and Koldihawa (PRL-100, 101) are older than normally expected, probably indicative of some hitherto unknown basal cultures in these regions. 14 C dates on in situ Megalithic materials do not seem to go beyond 200 BC. (author)

  10. Biokinetic studies on 14C-chitosan in rats

    International Nuclear Information System (INIS)

    Jia Minghong; Nishimura, Y.; Watanabe, Y.; Yukawa, M.

    1998-05-01

    The absorption and the basic metabolism of chitosan in rats are investigated. The results indicated that 14 C-chitosan from gastrointestinal tract was absorbed, metabolized and excreted quickly without re-bioavailability. The radioactive compounds perhaps with specifically chemical forms in serum, liver and the contents of small intestines were separated on GPC column and measured by radioactivity counting. A big pile of peaks with the retention volume almost same as that of standard 14 C-chitosan and another sharp one with the retention volume in the range of higher molecular weight same as that of BSA were discovered in analysis respectively for contents of intestine and serum or liver. The sharp peak would disappear if the proteins contained in the serum or liver were removed. In addition, and interesting tail peak, followed with the pile ones and eluted with the retention volume of lower molecular weight range same as that of chitooligosaccharides was also found in each of the 3 samples, ignoring the protein removal or not. These results suggested that most of 14 C-chitosan was not to be digested in intestine. On the other hand, a small amount of 14 C-chitosan was likely to be absorbed directly or after degraded to small molecular compounds into blood, liver and other tissues, and then connected with the proteins. Perhaps it is these trace materials that were playing important roles in reduction of the bioavailability of radiostrontium in rats

  11. The synthesis of [14C] C I pigment violet 19

    International Nuclear Information System (INIS)

    Filer, C.N.; Kelly, T.P.

    1990-01-01

    For the custom synthesis of radiolabeled compounds in the authors laboratory, aside from spectroscopic examination, their identity and radiochemical purity is routinely corroborated by demonstration of cochromatography with an authentic cold standard. In the synthesis of [ 14 C] red pigment 1 for the Cosmetic Toiletry and Fragrance Association, its insolubility precluded this. The preparation as well as characterization of 1 is described

  12. Synthesis of glycerides and glycerophospholipides labelled with 14C

    International Nuclear Information System (INIS)

    Danan, J.-L.

    1977-01-01

    Glycerides and glycerophospholipides labelled with 14 C were chemically synthetized using isopropylidene-D-glycerol prepared from D mannitol. The acylation method by labelled fatty acid chlorides was utilized. An original synthesis method was developed for the phospholipides using cyclic enediol pyrophosphate [fr

  13. Residues of 14C-cyolane in cottonseed products

    International Nuclear Information System (INIS)

    Zayed, S.M.A.D.; Osman, A.Z.; Fakhr, I.M.I.; Bahig, M.E.

    1981-01-01

    The systemic insecticide cyolane [2-(0,0-diethylphosphoryl)-imino-1,3-dithiolane] was prepared from 14 C-ethanol, phosphorus oxychloride and 2-amino-1,3-dithiolane. Cotton plants were treated with two applications of the insecticide under conditions of local agricultural practice. 14 C-residues in the crude oil and cake of the harvested cotton seeds amounted to 1.63 and 0.014 mg/kg respectively. About 50% of the 14 C-activity present in the crude oil was found to be eliminated by simulated commercial processes used for refining of the oil. Alkali treatment and bleaching removed 16% and 25% of the radioactive residues respectively. Winterization of the bleached oil at 5-7 0 C for 3 days effected a further elimination of 13%. 14 C-residues in the cotton seed products and in the samples of the refined oil were characterized and the main constituents identified using chromatographic techniques. (author)

  14. Review of high-sensitivity Radon studies

    Science.gov (United States)

    Wojcik, M.; Zuzel, G.; Simgen, H.

    2017-10-01

    A challenge in many present cutting-edge particle physics experiments is the stringent requirements in terms of radioactive background. In peculiar, the prevention of Radon, a radioactive noble gas, which occurs from ambient air and it is also released by emanation from the omnipresent progenitor Radium. In this paper we review various high-sensitivity Radon detection techniques and approaches, applied in the experiments looking for rare nuclear processes happening at low energies. They allow to identify, quantitatively measure and finally suppress the numerous sources of Radon in the detectors’ components and plants.

  15. Modeling of irradiated graphite {sup 14}C transfer through engineered barriers of a generic geological repository in crystalline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Poskas, Povilas; Grigaliuniene, Dalia, E-mail: Dalia.Grigaliuniene@lei.lt; Narkuniene, Asta; Kilda, Raimondas; Justinavicius, Darius

    2016-11-01

    There are two RBMK-1500 type graphite moderated reactors at the Ignalina nuclear power plant in Lithuania, and they are under decommissioning now. The graphite cannot be disposed of in a near surface repository, because of large amounts of {sup 14}C. Therefore, disposal of the graphite in a geological repository is a reasonable solution. This study presents evaluation of the {sup 14}C transfer by the groundwater pathway into the geosphere from the irradiated graphite in a generic geological repository in crystalline rocks and demonstration of the role of the different components of the engineered barrier system by performing local sensitivity analysis. The speciation of the released {sup 14}C into organic and inorganic compounds as well as the most recent information on {sup 14}C source term was taken into account. Two alternatives were considered in the analysis: disposal of graphite in containers with encapsulant and without it. It was evaluated that the maximal fractional flux of inorganic {sup 14}C into the geosphere can vary from 10{sup −} {sup 11} y{sup −} {sup 1} (for non-encapsulated graphite) to 10{sup −} {sup 12} y{sup −} {sup 1} (for encapsulated graphite) while of organic {sup 14}C it was about 10{sup −} {sup 3} y{sup −} {sup 1} of its inventory. Such difference demonstrates that investigations on the {sup 14}C inventory and chemical form in which it is released are especially important. The parameter with the highest influence on the maximal flux into the geosphere for inorganic {sup 14}C transfer was the sorption coefficient in the backfill and for organic {sup 14}C transfer – the backfill hydraulic conductivity. - Highlights: • Graphite moderated nuclear reactors are being decommissioned. • We studied interaction of disposed material with surrounding environment. • Specifically {sup 14}C transfer through engineered barriers of a geological repository. • Organic {sup 14}C flux to geosphere is considerably higher than inorganic

  16. Extraction of in situ cosmogenic 14C from olivine

    Science.gov (United States)

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

    2010-01-01

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

  17. A comparison of U/Th and rapid-screen 14C dates from Line Island fossil corals

    Science.gov (United States)

    Grothe, Pamela R.; Cobb, Kim M.; Bush, Shari L.; Cheng, Hai; Santos, Guaciara M.; Southon, John R.; Lawrence Edwards, R.; Deocampo, Daniel M.; Sayani, Hussein R.

    2016-03-01

    Time-consuming and expensive radiometric dating techniques limit the number of dates available to construct absolute chronologies for high-resolution paleoclimate reconstructions. A recently developed rapid-screen 14C dating technique reduces sample preparation time and per sample costs by 90%, but its accuracy has not yet been tested on shallow-water corals. In this study, we test the rapid-screen 14C dating technique on shallow-water corals by comparing 44 rapid-screen 14C dates to both high-precision 14C dates and U/Th dates from mid- to late-Holocene fossil corals collected from the central tropical Pacific (2-4°N, 157-160°W). Our results show that 42 rapid-screen 14C and U/Th dates agree within uncertainties, confirming closed-system behavior and ensuring chronological accuracy. However, two samples that grew ˜6500 years ago have calibrated 14C ages ˜1000 years younger than the corresponding U/Th ages, consistent with diagenetic alteration as indicated by the presence of 15-23% calcite. Mass balance calculations confirm that the observed dating discrepancies are consistent with 14C addition and U removal, both of which occur during diagenetic calcite recrystallization. Under the assumption that aragonite-to-calcite replacement is linear through time, we estimate the samples' true ages using the measured 14C and U/Th dates and percent calcite values. Results illustrate that the rapid-screen 14C dates of Holocene-aged fossil corals are accurate for samples with less than 2% calcite. Application of this rapid-screen 14C method to the fossil coral rubble fields from Kiritimati Island reveal significant chronological clustering of fossil coral across the landscape, with older ages farther from the water's edge.

  18. Nuclear Structure Effects in the Exotic Decay of $^{225}$Ac via $^{14}$C Emission

    CERN Multimedia

    2002-01-01

    % IS323 \\\\ \\\\ We propose to build at Isolde a high intensity $^{225}$Ac source by $\\beta$-decay of $^{225}$(Ra+Fr) beam, to be used at the superconducting spectrometer SOLENO of IPN-Orsay in order to study a possible fine structure in the spectrum of $^{14}$C ions spontaneously emitted by $^{225}$Ac.

  19. High sensitivity troponin and valvular heart disease.

    Science.gov (United States)

    McCarthy, Cian P; Donnellan, Eoin; Phelan, Dermot; Griffin, Brian P; Enriquez-Sarano, Maurice; McEvoy, John W

    2017-07-01

    Blood-based biomarkers have been extensively studied in a range of cardiovascular diseases and have established utility in routine clinical care, most notably in the diagnosis of acute coronary syndrome (e.g., troponin) and the management of heart failure (e.g., brain-natriuretic peptide). The role of biomarkers is less well established in the management of valvular heart disease (VHD), in which the optimal timing of surgical intervention is often challenging. One promising biomarker that has been the subject of a number of recent VHD research studies is high sensitivity troponin (hs-cTn). Novel high-sensitivity assays can detect subclinical myocardial damage in asymptomatic individuals. Thus, hs-cTn may have utility in the assessment of asymptomatic patients with severe VHD who do not have a clear traditional indication for surgical intervention. In this state-of-the-art review, we examine the current evidence for hs-cTn as a potential biomarker in the most commonly encountered VHD conditions, aortic stenosis and mitral regurgitation. This review provides a synopsis of early evidence indicating that hs-cTn has promise as a biomarker in VHD. However, the impact of its measurement on clinical practice and VHD outcomes needs to be further assessed in prospective studies before routine clinical use becomes a reality. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Highly sensitive high resolution Raman spectroscopy using resonant ionization methods

    International Nuclear Information System (INIS)

    Owyoung, A.; Esherick, P.

    1984-05-01

    In recent years, the introduction of stimulated Raman methods has offered orders of magnitude improvement in spectral resolving power for gas phase Raman studies. Nevertheless, the inherent weakness of the Raman process suggests the need for significantly more sensitive techniques in Raman spectroscopy. In this we describe a new approach to this problem. Our new technique, which we call ionization-detected stimulated Raman spectroscopy (IDSRS), combines high-resolution SRS with highly-sensitive resonant laser ionization to achieve an increase in sensitivity of over three orders of magnitude. The excitation/detection process involves three sequential steps: (1) population of a vibrationally excited state via stimulated Raman pumping; (2) selective ionization of the vibrationally excited molecule with a tunable uv source; and (3) collection of the ionized species at biased electrodes where they are detected as current in an external circuit

  1. A shell-derived time history of bomb 14C on Georges Bank and its Labrador Sea implications

    International Nuclear Information System (INIS)

    Weidman, C.R.; Jones, G.A.

    1993-01-01

    Bomb-produced radiocarbon has been used in the past as an important tracer of ocean circulation and as a valuable tool for calculating CO 2 air-sea exchange. However, previous studies of the ocean's time-varying bomb 14 C record have been confined exclusively to analyzing banded corals, and thus their application has been limited to the lower latitudes. The first time history of bomb 14 C from the high-latitude North Atlantic Ocean is obtained from a 54-year-old mollusc specimen, (Bivalvia) Arctica islandica, which was collected live from Georges Bank (41 degrees N) in 1990. The annual growth bands of its shell were analyzed for Δ 14 C using accelerator mass spectrometry, producing a Δ 14 C time history from 1939 to 1990. The depleted condition of the Georges Bank bomb 14 C signal relative to two coral-derived North Atlantic Δ 14 C time histories suggests a significant deepwater source for the waters on Georges Bank. Supported by previous work linking the origin of waters on Georges Bank to the Labrador Sea, the Δ 14 C budget on Georges Bank is modeled as Labrador Sea water, which largely becomes confined to the shelf and partially equilibrates with the atmosphere during a 1-year transit time from the Labrador Sea to Georges Bank. This model is also used to estimate a time history of bomb 14 C for the Labrador Sea. Prebomb Δ 14 C values calculated for the surface Labrador Sea suggest that a greater inventory of bomb 14 C has accumulated here than has previously been reported. Deduced variations in the ventilation and/or 14 CO 2 uptake rates in the Labrador Sea correspond with observed changes in surface salinity of the Labrador Sea, suggesting a reduction in deepwater formation during the late 1960s and 1970s. 59 refs., 11 figs., 2 tabs

  2. Synthesis of [methyl-{sup 14}C]crotonobetaine from DL-[methyl-{sup 14}C]carnitine

    Energy Technology Data Exchange (ETDEWEB)

    Loester, H.; Seim, H. [Leipzig Univ. (Germany). Inst. of Clinical Chemistry and Pathobiochemistry

    1996-02-01

    The causes of carnitine deficiency syndromes are not completely understood, but decomposition of L-carnitine in vivo is likely to be involved. Carnitine is metabolized to {gamma}-butyrobetaine, and crotonobetaine is probably an intermediate in this pathway. To validate experimentally the precursor-product relationship between the three physiologically occuring {gamma}-betaines - L-carnitine, crotonobetaine, {gamma}-butyrobetaine - labelling with stable or radioactive isotopes became necessary. Methyl-labelled carnitine isomers (L(-)-, D(+)- or DL-) or {gamma}-butyrobetaine can be easily synthesized by methylation of 4-amino-3-hydroxybutyric acid isomers or 4-aminobutyric acid, respectively. Because of problems with the 4-aminocrotonic acid, we synthesized labelled crotonbetaine from labelled carnitine. Thus, DL-[methyl-{sup 14}C]carnitine was dehydrated by reaction with concentrated sulfuric acid. After removal of the latter the products were separated and purified by ion exchange chromatography on DOWEX 50 WX8 (200 - 400 mesh) and gradient elution with hydrochloric acid. In addition to the labelled main product [methyl-{sup 14}C]crotonobetaine (yield about 50 %), [methyl-{sup 14}C]glycine betaine and [methyl-{sup 14}C]acetonyl-trimethylammonium (ATMA) were formed. The end products were identified by combined thin layer chromatography/autoradiography and quantified by liquid scintillation counting. (Author).

  3. Tracer experiment administering L-phenylalanine-U-{sup 14}C and L-tyrosine-U-{sup 14}C to the tissue slices of bamboo shoots

    Energy Technology Data Exchange (ETDEWEB)

    Kozukue, E. [Kenmei Women' s Junior Coll., Himeji, Hyogo (Japan); Mizuno, S.

    1987-09-15

    Uniformly {sup 14}C-labeled L-phenylalanine and L-tyrosine were administered to tissue slices of both top and base sections of bamboo shoots. Alcohol soluble substances were extracted and then separated into organic acid, sugar and amino acid fractions by ion exchange chromatography. The homogentisic acid fraction among the organic acids was collected by high-performance liquid chromatography (HPLC) and its radioactivity was measured, while the alcohol insoluble residue was used for the analysis of lignin aldehyde by the method of alkaline nitrobenzene oxidation. 1. The two labeled amino acids were steadily incorporated into the tissues during incubation and rapidly converted to organic acid, sugar and alcohol insoluble residue, especially the latter. 2. On determining the amount of phenylalanine converted to tyrosine, it was found that this was extremely small. 3. The incorporation of phenylalanine-U-{sup 14}C into alcohol insoluble residue was higher than that of tyrosine in both sections. 4. Although the conversion into lignin aldehyde from phenylalanine-U-{sup 14}C was higher than that from tyrosine-U-{sup 14}C, it was found that tyrosine incorporated into the shoots was converted to a remarkable extent for formation of lignin aldehyde. 5. The incorporation of phenylalanine and tyrosine into homogentisic acid was very low. From these results, we assume that the conversion of phenylalanine to tyrosine or of tyrosine to homogentisic acid is very small, and that a part of the high amount of tyrosine in the shoots may be used for formation of lignin.

  4. Model experiments for {sup 14}C water-age determinations

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, I; Stahl, W; Geyh, M; Fauth, F [Bundesanstalt fuer Bodenforschung, Hannover (Germany)

    1967-05-15

    The {sup 14}C age of water samples is calculated by assuming that fossil carbonate is dissolved by biogenic CO{sub 2} according to the equation x{sub 1} {center_dot} CaCO{sub 3} + (x{sub 1}+y{sub 1}) {center_dot} CO{sub 2} + H{sub 2}O = 2x{sub 1} {center_dot} HCO{sub 3} + y{sub 1} {center_dot} CO{sub 2} where x and y are the number of moles of the two carbon components before and after the dissolution process. In a closed system the relation y{sub 1} = K(T) (x{sub 1}){sup 3} must be satisfied additionally. The equilibrium constant K(T), which depends on the temperature, controls the concentrations of free CO{sub 2} and HCO{sub 3}. To investigate the mechanism of the dissolution, laboratory experiments under controlled conditions were carried out. Non-radioactive CaCO{sub 3}, which had a {delta}{sup 13}C-value of +30 per mille, and radioactive CO{sub 2} with {delta}{sup 13}C = -22 per mille were used. The purpose of these investigations was to check the validity of theoretical assumptions regarding the average {sup 14}C-activity and the {delta}{sup 13}C-value of the total carbon which is dissolved as CO{sub 2} and HCO{sub 3}. Furthermore, it was investigated whether, within the duration of the experiment, a possible exchange takes place between the undissolved carbon present in the CaCO{sub 3} and that present in the HCO{sub 3}. The importance of this lies in the fact that the method of {sup 14}C age determination is based on the assumption that such an exchange does not take place. The experiments which have been performed up to now show that in case of the simple CaCO{sub 3} - CO{sub 2} system, which has been considered first, this assumption is not justified even for a constant water temperature. If variations in the water temperature occur during the history of the water sample, precipitation and redissolution processes influence the {sup 14}C- and {delta}{sup 13}C -values differently. This is due to isotopic fractionation processes between the HCO{sub 3} and CO

  5. Standardization of 3H, 14C and 63Ni radiation sources by calorimetric method

    International Nuclear Information System (INIS)

    Khol'nova, E.A.; Kul'kova, L.P.

    1979-01-01

    The calorimetric method of determination of activity of radionuclides 3 H, 14 C and 63 Ni with low mean energies of β-particles has, as compare to other methods which had been used for determination of activity of these nuclides, a number of advantages, because a nuclide to be measured can be introduced into the calorimeter in any physical and chemical state. It is not necessary to distroy integrity ane leek-proofness of a source wnich can be of arbitrary type. There is no correction for absorption and self-absorption of β-particles and measuring instruments are relatively simple. As a limitation of this method is it's low sensitivity which can be owercomed by means of application of modern high sensitivity calorimeters. Such calorimeters have been developed in the Mendeleev All-Union research Institute. The calorimetric installation consists of 3 independent β-calorimeters of differential-double type, working in the regime of heat equilibrium and beeng intended for different by sise and shape sources. Then, there are thermostatting device of special desighn and electric measuring device. Number of thermocouples in each calorimeter is from 75 to 120 and sensitivity of calorimeters is from 2.45x10 -7 to 4.5x10 -7 Bt/mm depending on the type of calorimeter. Calorimeters are intended for measuring activities from 10 9 to 10 12 Bk. Error of measurement of activities equals 0.8-1.5% (with confidence level of 0.99%). The main portion of error consists of error in the medium energy β-spectra. The calorimeter error itself is much more lower. Soueces, which have been measured in the calorimeter than can be used for preparation of solutions and sources of lower activity [ru

  6. Reactions of saccharides catalyzed by molybdate ions. XXXIII. Use of. cap alpha. (U-/sup 14/C)glucan for preparation of /sup 14/C-labelled saccharides

    Energy Technology Data Exchange (ETDEWEB)

    Bilik, V; Biely, P [Institute of Chemistry, Centre for Chemical Research, Slovak Academy of Sciences, Bratislava (Czechoslovakia); Kolina, J [Ustav pro Vyzkum, Vyrobu a Vyuziti Radioisotopu, Prague (Czechoslovakia)

    1984-01-01

    D-(U-/sup 14/C)glucose obtained in acid hydrolysis of ..cap alpha..-(U-/sup 14/C)glucan (2 M-HCl) was epimerized under a catalytic action of molybdate ions to D-(U-/sup 14/C)mannose isolated with a 20% yield. Oxidative degradation of 4-nitrophenylhydrazones of D-(U-/sup 14/C)arabinose and D-(U-/sup 14/C)xylose resulted in D-(U-/sup 14/C)erythrose and D-(U-/sup 14/C)threose, respectively, with a 15% yield relative to the starting aldopentoses. Nitromethane synthesis with D-(U-/sup 14/C)lyxose followed by oxidative decomposition of the corresponding nitrohexitols yielded /sup 14/C-labelled D-galactose. Described is also the preparation of D-(U-/sup 14/C)arabinose from D-(U-/sup 14/C)glucose and the conversion of D-(U-/sup 14/C)arabinose to D-(U-/sup 14/C)xylose and D-(U-/sup 14/C)lyxose.

  7. Seasonal changes in within-canopy allocation of 14C-photosynthate by white oak

    International Nuclear Information System (INIS)

    McLaughlin, S.B.; McConathy, R.K.; Beste, B.

    1979-01-01

    Seasonal changes in photosynthate translocation and allocation of two mature, codominant white oak trees were studied by following rates of movement of 14 C-photosynthate from foliage labeled with 14 CO 2 . Loss rates were determined by sampling foliage at 5 min and 1, 4, and 7 days after labeling on each of five dates (April 22 to October 4). Incorporation of 14 C-photosynthate into 1-, 3-, and 5-year-old branches was determined 7 days after tagging. Losses of 14 C from leaves were rapid by day 1 (less than or equal to 80 percent), greatly reduced by day 4, and ranged fom 63 to 91 percent by day 7. Maximum retention of initial activity levels occurred in April for leaves (44 percent) and in October for branches (15 percent). Approximately equal apportionment of activity between leaves and branches did not occur until August. Highest total retention of photosynthate in the canopy occurred in April (due to high incorporation in leaves) and June (due to high retention in both leaves and branches). Based on measured retention and estimated respiration losses, translocation of the original 14 C-photosynthate from the canopy was calculated to be approximately 0 percent in April, 30 percent in June, and 60 percent in October. These results indicate that canopy growth and maintenance impose a significant drain on availability of photosynthate throughout the growing season

  8. Ground water dating on the basis of the 14C content of dissolved humic and fulvic acids. Final report

    International Nuclear Information System (INIS)

    Kim, J.I.; Artinger, R.; Buckau, G.; Kardinal, C.; Geyer, S.; Wolf, M.; Halder, H.; Fritz, P.

    1995-05-01

    The groundwater dating on the basis of the 14 C content of dissolved organic carbon (DOC) is studied. Fulvic acids (FA) and humic acids (HA) are used as DOC fractions. In addition, the groundwaters are dated with the 14 C content of the dissolved inorganic carbon (DIC). The isotopic contents of 2 H, 3 H, 13 C, 15 N, 18 O, and 34 S of groundwater and humic substances are alse determined. The isolated humic substances are characterized with regard to their chemical composition as well as their molecular size and spectroscopic properties. For aquifer systems which have a neglectable content of sedimentary organic carbon (SOC), the 14 C dating of FA show plausible groundwater ages. In aquifer systems with a high SOC content, the mixing of 14 C free FA from sediment partly falsifies the 14 C groundwater age as determined by dissolved FA. Due to the high transfer of HA from sediment to groundwater, HA are less suitable for groundwater dating. The FA characterization allows the distinction between FA of sedimentary origin and FA which infiltrate with seepage water. Several starting points for a correction of the calculated 14 C ages of FA exist. The results indicate, 14 C groundwater dating with fulvic acids is a valuable expansion of groundwater dating methods. (orig.) [de

  9. CALDER: High-sensitivity cryogenic light detectors

    International Nuclear Information System (INIS)

    Casali, N.; Bellini, F.; Cardani, L.

    2017-01-01

    The current bolometric experiments searching for rare processes such as neutrinoless double-beta decay or dark matter interaction demand for cryogenic light detectors with high sensitivity, large active area and excellent scalability and radio-purity in order to reduce their background budget. The CALDER project aims to develop such kind of light detectors implementing phonon-mediated Kinetic Inductance Detectors (KIDs). The goal for this project is the realization of a 5 × 5 cm"2 light detector working between 10 and 100mK with a baseline resolution RMS below 20 eV. In this work the characteristics and the performances of the prototype detectors developed in the first project phase will be shown.

  10. The synthesis of nucleoside bases with 14 C

    International Nuclear Information System (INIS)

    Matloubi, H.; Mehrdad, M.

    1997-01-01

    Labelled organic compounds have been widely and diligently applied to research problems in life science and chemistry. In many laboratories they have lost their novelty and have been become conventional research tools since long time ago. these applications frequently require organic compounds substituted (or labelled) with isotopes, but the isotopes are (with certain exception) extracted in first place in simple inorganic forms. The conversion of these simple form into the more or less complex labelled compounds called for by research workers has become in effect a new branch of practical organic chemistry. The preparation of labelled compounds, carbon-14 is probably more extensively and variously used than any other isotope. It emits only beta-particles. In this project, two kinds of nucleoside bases under the name uracil-2- 14 C and thymine (methyl- 14 C) were prepared.(author). 14 refs., 3 figs., 2 tabs

  11. 10Be and 14C in the Earth system

    International Nuclear Information System (INIS)

    Oeschger, H.; Beer, J.; Andree, M.

    1987-01-01

    In a very short period of time, 10 Be data have significantly improved our knowledge in various fields of Earth and planetary sciences. Examples are solar modulation of isotope production, revealed in 10 Be ice-core profiles; geomagnetic modulation of isotope production, revealed in 10 Be ice-core (from the past 10 ka) and ocean-sediment profiles (geomagnetic reversals); climatic effects reflected in 10 Be profiles in loess and polar ice cores ( 10 Be behaviour in atmosphere); comparison of 10 Be and 14 C variations (tree rings) from carbon-cycle models and information on ocean circulation history from 14 C measurements on benthic and planktonic Foraminifera in ocean sediments. An overview on work in collaboration with the Zurich AMS (accelerator mass spectroscopy) facility is given. (author)

  12. New proportional counter assembly in Gliwice 14C laboratory

    International Nuclear Information System (INIS)

    Moscicki, W.; Zastawny, A.

    1977-01-01

    The design and parameters are described of a proportional counter for low level counting. The cathode tube 80 mm in diameter and 30 cm in length is made of pure copper. The anode is a tungsten wire 0.05 mm in diameter. The cathode tube is surrounded by a cylindrical ring container with mercury. The total volume of the counter is 1.5 l and it is filled with carbon dioxide. At a pressure of 1 at of CO 2 the counter background is 4.20+-0.05 cpm and contemporary 14 C net effect 10.22+-0.10 cpm; at a pressure of 2 at of CO 2 the background is 4.40+-0.05 cpm and the contemporary 14 C net effect 20.53+-10 cpm. The efficiency of the proportional counter is 88% in both cases. (J.B.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  14. High sensitive radiation detector for radiology dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  15. High sensitivity amplifier/discriminator for PWC's

    International Nuclear Information System (INIS)

    Hansen, S.

    1983-01-01

    The facility support group at Fermilab is designing and building a general purpose beam chamber for use in several locations at the laboratory. This pwc has 128 wires per plane spaced 1 mm apart. An initial production of 25 signal planes is anticipated. In proportional chambers, the size of the signal depends exponentially on the charge stored per unit of length along the anode wire. As the wire spacing decreases, the capacitance per unit length decreases, thereby requiring increased applied voltage to restore the necessary charge per unit length. In practical terms, this phenomenon is responsible for difficulties in constructing chambers with less than 2 mm wire spacing. 1 mm chambers, therefore, are frequently operated very near to their breakdown point and/or a high gain gas containing organic compounds such as magic gas is used. This argon/iso-butane mixture has three drawbacks: it is explosive when exposed to the air, it leaves a residue on the wires after extended use and is costly. An amplifier with higher sensitivity would reduce the problems associated with operating chambers with small wire spacings and allow them to be run a safe margin below their breakdown voltage even with an inorganic gas mixture such as argon/CO2, this eliminating the need to use magic gas. Described here is a low cost amplifier with a usable threshold of less than 0.5 μA. Data on the performance of this amplifier/discriminator in operation on a prototype beam chamber are given. This data shows the advantages of the high sensitivity of this design

  16. High sensitive radiation detector for radiology dosimetry

    International Nuclear Information System (INIS)

    Valente, M.; Malano, F.; Molina, W.; Vedelago, J.

    2014-08-01

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  17. 14C as a tracer of labile organic matter in Antarctic benthic food webs

    Science.gov (United States)

    Purinton, Brett L.; DeMaster, David J.; Thomas, Carrie J.; Smith, Craig R.

    2008-11-01

    . lorioli and M. musculus; mean=-136.2±8.5 per mil) was distinct ( p=0.0008) from the mean 14C abundance in the body tissues of the four surface deposit feeders (echiuran worm, P. vignoni, P. murrayi, and B. fusciviculum; -122.6±12.3 per mil). The mean 14C abundance of the gut contents from the sub-surface deposit feeders (-178.0±18.6 per mil) also was significantly depleted ( p=0.0009) relative to that of the surface deposit feeders (-149.5±26.6 per mil). The 14C measurements proved to be a much more sensitive tracer for tracking labile organic carbon during ingestive and assimilatory processes than the stable isotopes of carbon or nitrogen.

  18. Accuracy of the 14 C-urea breath test for the diagnosis of Helicobacter pylori

    International Nuclear Information System (INIS)

    Gomes, Ana Thereza Britto; Secaf, Marie; Modena, Jose Luiz Pimenta; Troncon, Luiz Ernesto de Almeida; Oliveira, Ricardo Brandt de

    2002-01-01

    The development of simple, accurate and low-expense techniques for detection of Helicobacter pylori infection has great relevance. The objective was to determine the accuracy of a rapid 14 C-urea breath test (UBT) employing a very simple device for breathed air collection. One hundred and thirty-seven adult patients who underwent upper gastrointestinal endoscopy in the Clinical Hospital. The main measurements were histology for Helicobacter pylori (HP); urease test; urea breath test (UBT). One hundred and fifteen patients were infected by HP (HP +) according to both histology and the urease test, and 22 patients were HP-negative (HP-), according to the same two tests. UBT was capable of discriminating between HP + and HP- in a way that was similar to the combination of urease test and histology. When this combination of results is taken as the 'gold standard' for HP infection, the sensitivity and specificity of UBT are both greater than 90% for a range of cut-off points and breathed air collection times. It was concluded that the rapid UBT employing a simple device for air collection has a high accuracy in determining HP infection. (author)

  19. Spectrophotometric determination of sugars labelled with 14C

    International Nuclear Information System (INIS)

    Vatsikova, A.; Kralikova, M.; Vyskochilova, Z.

    1982-01-01

    Comparative analysis of methods for determination of microgram amounts of 14 C-labelled sugars has been carried out. The ferricyanide and Shomodyi-Nelson methods were approbated in experimental study. The relative error of the ferricyanide method was found to be smaller than that of the Shomodyi-Nelson method. Thus the ferricyanide method was used for obtaining calibration curves for 15 sugars. The accuracy for sugar amounts higher than 3 μg/10 ml was better than +, - 5% [ru

  20. Degradation of 14C-glyphosate in compost amended soils.

    Science.gov (United States)

    Alexa, E; Bragea, M; Sumalan, R; Negrea, M; Lazureanu, A

    2009-01-01

    Glyphosate (N-phosphonomethyl-glycine), the active ingredient in several herbicide formulations, is a non-selective, post-emergent herbicide used in a variety of crop and non-crop situations. Glyphosate is a non-volatile herbicide that is relatively immobile in soil. Its degradation is due to microbiological processes and most laboratory studies have been conducted with 14C-glyphosate with the rate of 14CO2 evolution being used as an indication of herbicide breakdown. In this paper we have studied the glyphosate degradation in compost amendment soils using Scientilator Liquid TRIATHLER and Glyphosate-phosphonomethyl-14C-labeled with specific activity 2,2mCi/mmol. Four types of soils have been taken under study: Black Chernozem, Vertisol, Gleysol and Phaeozem with different characteristics. For the each type of soil have been realized four experimental variants (glyphosate blind sample with 1,5 ppm, concentration, autoclaved soil, soil with glyphosate and addition of compost in field concentration of 40 t/ha, respectively 60 t/ha. The mineralization curves of 14CO2 accumulated were compared during of 40 days. All the mineralization curves for the soils exhibited same patterns, with only two phases, the initial rapid phase of degradation, for about 20 days, attributed to microbial action on the free glyphosate and the second slow phase, when the curves attained plateaus. Compost applied with different concentrations to Vertisol and Black Chernozem did not appear to stimulate the microbial degradation of glyphosate. In Gleysol and Phaeozem with lower humus content, the mineralization curve of 14C indicate the increase degradation capacity, expressed as accumulated 14CO2 as % total 14C, with the increase of compost concentration.

  1. The study of variations and environmental applications 14C

    International Nuclear Information System (INIS)

    Simon, J.

    2010-01-01

    The primary aim of the presented thesis is to explain experimentally observed 14 C variations in the outer atmosphere. Physical models have been developed to quantify directly immeasurable phenomena relevant in the field of radiocarbon dynamics. Namely atmospheric stability, 14 C transport from the stratosphere to the lower troposphere and fossil carbon dioxide emissions to the atmosphere. Finally these models have been used as the pillars of the united theory of Δ 14 C dynamics. Besides the presented main theoretical outputs, this thesis also provides couple of potentially implementable by-products. First of them is a method to evaluate so called 'equivalent mixing height' and turbulent diffusion coefficient using temporal changes of 222 Rn concentration in the boundary layer of the atmosphere. The elaborated mathematical apparatus for the evaluation of aerosol scavenging by raindrops can be utilized in the models of pollutant dispersion. Information on turbulent diffusion coefficient at higher atmospheric levels is important for the models of stratospheric and ozonospheric dynamics. Nowadays, when one can measure and even feel the greenhouse effect consequences, the importance of an independent method for carbon dioxide fossil emissions assessment is obvious. Besides theoretical outcome, the thesis also presents experimental results. A network of CO 2 sampling sites has been established in Bratislava and the outskirts in the vicinity of the town. Together with mountain site Chopok the network brought a unique information on 14 C distribution. Atmospheric measurements of 7 Be and 222 Rn activity are also presented here. Finally the PC codes have been developed to bridge a gap between experimental and theoretical results. (author)

  2. Pediatric microdose and microtracer studies using 14C in Europe.

    Science.gov (United States)

    Turner, M A; Mooij, M G; Vaes, W H J; Windhorst, A D; Hendrikse, N H; Knibbe, C A J; Kõrgvee, L T; Maruszak, W; Grynkiewicz, G; Garner, R C; Tibboel, D; Park, B K; de Wildt, S N

    2015-09-01

    Important information gaps remain on the efficacy and safety of drugs in children. Pediatric drug development encounters several ethical, practical, and scientific challenges. One barrier to the evaluation of medicines for children is a lack of innovative methodologies that have been adapted to the needs of children. This article presents our successful experience of pediatric microdose and microtracer studies using (14) C-labeled probes in Europe to illustrate the strengths and limitations of these approaches. © 2015 ASCPT.

  3. Biodegradation of 14 C-atrazine under outdoor conditions

    International Nuclear Information System (INIS)

    Queiroz, Brigida Pimentel Villar de

    1997-10-01

    Uniformly 14 C-ring labeled atrazine (5 L/ha) was applied to a Typical Hapludox Brazilian Soil sample which was incubated under outdoor conditions. Sample of 200 g (dry weight base) of fresh soil were distributed in Erlenmeyer flasks and the moisture was adjusted for 2/3 rds of the soil field capacity. The flasks were then buried in the Lysimeter Station when they were incubated. The experiment started jointly with a corn planting. The 14 C O 2 was analyzed every 15 day, during a period of 150 days. The desorbed, extracted and bound residues were analyzed. The extracted soil was fractionated and the residues in the humin, fulvic and humic acids were determined. At the end of the incubation period (150 days), the 14 CO 2 evolved reached up to 36% of the total applied activity, the bound residues were detected in about the same (34%) during the inoculation period, and were distributed in the fractions of fulvic acids (29,91%), humic acids (6,83%) and humin (63,26%). The metabolites formed in the desorbed residues and in the extracted residues were determined using thin layer chromatography with 14 C-detector. After 150 days incubation, desorbed soil residues were identified as atrazine (52,72%), hydroxiatrazine (44%) and desisopropilatrazine (3,28%). The extractable residues contained atrazine (79,29%), hydroxiatrazine (16,22%), desisopropilatrazine (2,25%) and desetylatrazine (2,24%). (author)

  4. Synthesis of 14C-labelled α-methyl tyrosine

    International Nuclear Information System (INIS)

    Rajagopal, S.; Venkatachalam, T.K.; Conway, T.; Diksic, M.

    1992-01-01

    A new route for the preparation of radioactively labelled α-methyl L-tyrosine is described. The labelling at the α position has been successfully achieved with 14 C-, 11 C- (very preliminary, unpublished), and 3 H-labelled methyl iodide. A detailed report on 14 C-labelling at the α position and the hydrolysis of 4-methoxy α-methyl phenylalanine is presented. The alkylation proceeds via the methylation of the carbanion of N-benzylidene 4-methoxy phenylalanine methyl ester 2. Hydrolysis of 4-O methyl tyrosine to tyrosine by HBr and HI were analysed and used in the optimization of the hydrolysis conditions of 4. Enantiomeric purity of the isolated L-isomer has been found to be 99% as judged by HPLC. Pseudo first-order rate constant for the hydrolysis of 14 C-labelled α-methyl 4-methoxy phenyl alanine methyl ester was determined. Preliminary findings of the 3 H- and 11 C-radiolabelled α-methyl tyrosine (methyl labelled) are also mentioned. For the first time it was shown that α-methyl D,L-tyrosine can be separated into enantiomerically pure α-methyl D- and L-tyrosine using a CHIRALPAK WH column. (author)

  5. Synthesis of disodium [benzene-U-{sup 14}C]-(4-chlorophenylthio)methylenediphosphonate, [benzene-U-{sup 14}C]-tiludronate

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, Alain; Ellames, G.J. [Alnwick Research Centre (United Kingdom). Dept. of Metabolism and Pharmacokinetics

    1995-12-31

    Disodium [benzene-U-{sup 14}C]-(4-chlorophenylithio)methylenediphosphonate, [benzene-{sup 14}C]-Tiludronate, 2, has been prepared in six steps from [benzene-U-{sup 14}C]-acetanilide in an overall radiochemical yield of 41%. A key step in this transformation was the efficient conversion of [U-{sup 14}C]-4-chloroaniline to [benzene-U-{sup 14}C]-4-chlorophenylthiocyanate, 5, in 83% yield by treatment of the corresponding diazonium salt, 9 with iron(111) thiocyanate. It should be noted that formation of the isomeric [benzene-U-{sup 14}C]-4-chlorophenylisothiocyanate, 11, as a byproduct, was observed in only {approx} 1% yield. (author).

  6. Phosphorus effect on the uptake, translocation and accumulation of the 14C-urea in orchard grass (Dactylis glomerata L.)

    International Nuclear Information System (INIS)

    Panak, H.; Nowak, G.; Nowak, J.; Akademia Rolniczo-Technicza, Olsztyn

    1981-01-01

    The effect of different phosphorus supplies on the uptake, translocation and accumulation of 14 C-urea by orchard grass was investigated. Phosphorus starvation inhibits the uptake, translocation and accumulation of the carbon of urea similarly to the nitrogen of urea. As compared with the uptake process the reduction of the accumulation is much more effected by the inhibition of the carbon translocation from roots to the aboveground parts. Lack of phosphorus also decreases the incorporation of the 14 C of urea into high-molecular compounds. The effect of phosphorus deficit on the accumulation of 14 C-urea increases with time of starvation. (orig.)

  7. In vitro transfer rate of 14C from acetate-1-14C into ovarian steroids in the rat ovary during the estrous cycle and effects of LH and FSH

    International Nuclear Information System (INIS)

    Kimura, F.; Ishida, S.; Seto, K.; Kawakami, M.

    1976-01-01

    Fluctuations of ovarian biosynthetic activity and effects of exogenous LH and FSH on it during the estrous cycle were investigated by measuring in vitro transfer rates of 14 C from 14 C-1-acetate into progesterone (P), 20α-hydroxy-pregn-4-en-3-one (20α-OH-P) and estrogen (estradiol and estrone, E) in the ovarian homogenates from rats autopsied at 2 hour intervals. The transfer rate of 14 C from 14 C-1-acetate into P was lowest in the afternoon of estrus and increased from the morning of diestrus 1, making its peaks during the afternoon of diestrus 2 and in the midnight of proestrus. The transfer of 14 C into 20α-OH-P was high on the days of diestrus 2 and proestrus with its peak in the afternoon of the latter day. The maximum transfer of 14 C into E in the afternoon of proestrus and a high rate in the morning of estrus with relatively low one in the midnight were observed. Exogenously injected LH (150 μg) or FSH (150 μg) was eigther stimulatory or inhibitory to the transfer rates of 14 C from 14 C-1-acetate into ovarian steroids. During day time of diestrus 2 and midnight between proestrus and estrus, the transfer of 14 C into P and 20α-OH-P increased by LH, and during day time of proestrus and from the afternoon of estrus to the morning of diestrus 1 decreased. The transfr of 14 C into E increased by LH from the afternoon of diestrus 2 to the morning of proestrus, and decreased during the ofternoon of proestrus and from the afternoon of estrus to the morning of diestrus 2. Administration of FSH was also stimulatory or inhibitory. The 14 C transfer into P and 20α-OH-P increased by FSH from the afternoon of estrus to the morning of proestrus, but in the afternoon of proestrus they decreased. Transfer of 14 C into E increased by FSH significantly on the days of diestrus 2 and proestrus, and slightly on the day of estrus, while it decreased in the afternoon of diestrus 1. (author)

  8. A STUDY ON ADSORPTION AND DESORPTION BEHAVIORS OF 14C FROM A MIXED BED RESIN

    Directory of Open Access Journals (Sweden)

    SEUNG-CHUL PARK

    2014-12-01

    Full Text Available Spent resin waste containing a high concentration of 14C radionuclide cannot be disposed of directly. A fundamental study on selective 14C stripping, especially from the IRN-150 mixed bed resin, was carried out. In single ion-exchange equilibrium isotherm experiments, the ion adsorption capacity of the fresh resin for non-radioactive HCO3− ion, as the chemical form of 14C, was evaluated as 11mg-C/g-resin. Adsorption affinity of anions to the resin was derived in order of NO3− > HCO3− ≥ H2PO4−. Thus the competitive adsorption affinity of NO3− ion in binary systems appeared far higher than that of HCO3− or H2PO4−, and the selective desorption of HCO3− from the resin was very effective. On one hand, the affinity of Co2+ and Cs+ for the resin remained relatively higher than that of other cations in the same stripping solution. Desorption of Cs+ was minimized when the summation of the metal ions in the spent resin and the other cations in solution was near saturation and the pH value was maintained above 4.5. Among the various solutions tested, from the view-point of the simple second waste process, NH4H2PO4 solution was preferable for the stripping of 14C from the spent resin.

  9. AMS-14C analysis of modern teeth: A comparison between two sample preparation techniques

    Science.gov (United States)

    Solis, C.; Solis-Meza, E.; Morales, M. E.; Rodriguez-Ceja, M.; Martínez-Carrillo, M. A.; Garcia-Calderon, D.; Huerta, A.; Chávez, E.

    2017-09-01

    AMS-14C analysis of modern teeth has become important for forensic studies. 14C content in human teeth reflects the 14C atmospheric concentration during its formation and allows the calculation of the actual year of birth. Through AMS, it is possible to measure the 14C concentrations in a tissue with high precision. However, there is a debate about which should be the best fraction for teeth carbon dating: collagen or enamel. This work focuses on the results obtained from enamel and collagen extracted from Mexican people in order to compare them. Collagen from dental pieces donated from people older than 60-years-old have been included to understand the turnover process and usefulness of collagen to determine the date of birth. Our results indicate that when a single dental piece is available, enamel method allows the determination of the tooth formation date. Dating collagen of the same tooth helps to discriminate if the formation date belongs to the left or the right side of the peak bomb, but also corroborates, the ages obtained through enamel analysis.

  10. Dynamics of 14C-labeled glucose and ammonium in saline arable soils

    International Nuclear Information System (INIS)

    Vuelvas-Solorzano, Alma; Hernandez-Matehuala, Rosalina; Conde-Barajas, Eloy; Cardenas-Manriquez, Marcela; Luna-Guido, Marco L.; Dendooven, Luc

    2009-01-01

    Organic matter dynamics and nutrient availability in saline agricultural soils of the State of Guanajuato might provide information for remediation strategies. 14 C labeled glucose with or without 200 mg kg - 1 of NH 4 + -N soil was added to two clayey agricultural soils with different electrolytic conductivity (EC), i.e. 0.94 dS m - 1 (low EC; LEC) and 6.72 dS m - 1 (high EC; HEC), to investigate the effect of N availability and salt content on organic material decomposition. Inorganic N dynamics and production of CO 2 and 14 CO 2 were monitored. Approximately 60 % of the glucose- 14 C added to LEC soil evolved as 14 CO 2 , but only 20 % in HEC soil after the incubation period of 21 days. After one day, 14 C was extractable from LEC soil, but > 500 mg 14 C from HEC soil. No N mineralization occurred in the LEC and HEC soils and glucose addition reduced the concentrations of inorganic N in unamended soil and soil amended with NH 4 + -N. The NO 2 - and NO 3 - concentrations were on average higher in LEC than in HEC soil, with exception of NO 2 - in HEC amended with NH 4 + -N. It was concluded that increases in soil EC reduced mineralization of the easily decomposable C substrate and resulted in N-depleted soil. (author)

  11. Distribution of the bispyridinium oxime [14C] HI-6 in male and female rats

    International Nuclear Information System (INIS)

    Lundy, P.M.; Hand, B.T.; Hamilton, M.G.; Broxup, B.R.; Yipchuck, G.

    1990-01-01

    The present study was designed first to determine the distribution pattern and concentration of [ 14 C] HI-6 in rats, and secondly, to determine the possibility that HI-6 might be located in high concentrations in critical tissues in the female as opposed to the male. To these ends, [ 14 C] HI-6 was administered to groups of male and female rats and its radiolabelled distribution determined by whole body autoradiography and/or by measurement of its actual concentration, by scintillation spectrometry. The experiments were repeated in the presence of 2xLD 50 soman and supporting therapy with atropine. In both sexes, HI-6 levels were highest in the kidney, followed in order by cartilage > plasma > liver > heart ≥ lung>> diaphragm > brain and spinal cord. The relative distribution in the two sexes was confirmed by both methods and was not significantly altered in the presence of soman and atropine. The lack of a measurable difference in tissue distribution of [ 14 C] HI-6 derived radioactivity between males and females suggested that the hormone-dependent difference in the protective effects previously observed was not due to selective accumulation of [ 14 C] HI-6 in organs believed to be important in its therapeutic activity, such as brain or diaphragm. (orig.)

  12. High sensitivity thermal sensors on insulating diamond

    Energy Technology Data Exchange (ETDEWEB)

    Job, R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Denisenko, A.V. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Zaitsev, A.M. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Melnikov, A.A. [Belarussian State Univ., Minsk (Belarus). HEII and FD; Werner, M. [VDI/VDE-IT, Teltow (Germany); Fahrner, W.R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices

    1996-12-15

    Diamond is a promising material to develop sensors for applications in harsh environments. To increase the sensitivity of diamond temperature sensors the effect of thermionic hole emission (TE) over an energetic barrier formed in the interface between highly boron-doped p-type and intrinsic insulating diamond areas has been suggested. To study the TE of holes a p-i-p diode has been fabricated and analyzed by electrical measurements in the temperature range between 300 K and 700 K. The experimental results have been compared with numerical simulations of its electrical characteristics. Based on a model of the thermionic emission of carriers into an insulator it has been suggested that the temperature sensitivity of the p-i-p diode on diamond is strongly affected by the re-emission of holes from a group of donor-like traps located at a level of 0.7-1.0 eV above the valence band. The mechanism of thermal activation of the current includes a spatial redistribution of the potential, which results in the TE regime from a decrease of the immobilized charge of the ionized traps within the i-zone of the diode and the correspondent lowering of the forward biased barrier. The characteristics of the p-i-p diode were studied with regard to temperature sensor applications. The temperature coefficient of resistance (TCR=-0.05 K{sup -1}) for temperatures above 600 K is about four times larger than the maximal attainable TCR for conventional boron-doped diamond resistors. (orig.)

  13. Transportable high sensitivity small sample radiometric calorimeter

    International Nuclear Information System (INIS)

    Wetzel, J.R.; Biddle, R.S.; Cordova, B.S.; Sampson, T.E.; Dye, H.R.; McDow, J.G.

    1998-01-01

    A new small-sample, high-sensitivity transportable radiometric calorimeter, which can be operated in different modes, contains an electrical calibration method, and can be used to develop secondary standards, will be described in this presentation. The data taken from preliminary tests will be presented to indicate the precision and accuracy of the instrument. The calorimeter and temperature-controlled bath, at present, require only a 30-in. by 20-in. tabletop area. The calorimeter is operated from a laptop computer system using unique measurement module capable of monitoring all necessary calorimeter signals. The calorimeter can be operated in the normal calorimeter equilibration mode, as a comparison instrument, using twin chambers and an external electrical calibration method. The sample chamber is 0.75 in (1.9 cm) in diameter by 2.5 in. (6.35 cm) long. This size will accommodate most 238 Pu heat standards manufactured in the past. The power range runs from 0.001 W to <20 W. The high end is only limited by sample size

  14. Studies on distribution and excretion of 14C-glycerol in rats, rabbits and mice

    International Nuclear Information System (INIS)

    Takanashi, Shigeru; Kamiyama, Hiroshi; Suzuki, Hidetaka; Tohira, Yasuo; Ogawa, Machiko

    1978-01-01

    Tissue distribution and excretion of uniformly labeled 14 C-glycerol were investigated using rats, rabbits and mice. Blood disappearance half life of 14 W/V% 14 C-glycerol in mice (1 ml/head), rats (1 ml/head) and rabbits (2 ml/head) given intravenously was 0.4, 1.8 and 2.4 hours, respectively. When 14 W/V% 14 C-glycerol was injected in rats (1 ml/head) and rabbits (2 ml/head), 65% of administered radioactivity was excreted in to expired air within 48 hrs. This suggests that glycerol is mostly metabolised via the Embden-Meyehof pathway and the TCA cycle, and finally converted to CO 2 and H 2 O. At a low dose, the conversion ratio to CO 2 was greater than the case of a high dose, and a inverse relationship was observed between the CO 2 -conversion ratio and the dose. At levels above 1 ml of 56 W/V% glycerol, an approximately constant portion of the administered dose appeared to be oxidized. The results of the whole body autoradiogram showed the distribution of the radioactivity throughout the body. Disappearance of radioactivity from liver and blood was rapid, but transport to brain, excretion to the salivary gland, and secretion to Harder's gland were slow. The distribution in tissues showed that the highest distribution of 14 C-glycerol was found in the carcass; liver showed the next highest distribution; high distribution was also found initially in the kidneys; brain, heart, lung and spleen showed low distribution, but they decreased with time elapsed. Disappearance of radioactivity from the brain was relatively slower than the liver. Besides, another result indicated that in pregnant mice 14 C-glycerol did not cross the placenta very quickly. The fact that the apparent disappearance rate from the foetuses does not seem to parallel that of the placenta is suggestive of selective accumulation in foetal tissues. (auth.)

  15. Uptake of [2-14C]abscisic acid and distribution of 14C in apple embryos

    International Nuclear Information System (INIS)

    Barthe, P.; Bulard, C.

    1981-01-01

    Pyrus malus L. var. Golden delicious embryos were incubated with (+-)-[2- 14 C] abscisic acid (ABA). After incubations of various durations, the radioactivity was measured in whole embryos, cotyledons, and embryonic axes. With either 48-h or 16-d incubation periods, the uptake of [ 14 C] ABA depended upon the mode of culture used. The lowest values corresponded to the absorption by the embryonic axis, the highest to the absorption by the distal parts of the two cotyledons. The cotyledons accumulated the main part of the radioactivity under all conditions. Dormant and almost completely after-ripened embryos cultivated for 4 d showed no significant differences in the radioactivity uptake for identical modes of culture. There was a linear relationship between exogenous ABA concentrations (0.5 to 3.10 -5 M) and ABA uptake for embryos cultivated for 4 d with the distal parts of the cotyledons immersed in the medium. (orig.) [de

  16. Uptake of (2-/sup 14/C)abscisic acid and distribution of /sup 14/C in apple embryos

    Energy Technology Data Exchange (ETDEWEB)

    Barthe, P.; Bulard, C.

    1981-01-01

    Pyrus malus L. var. Golden delicious embryos were incubated with (+-)-(2-/sup 14/C) abscisic acid (ABA). After incubations of various durations, the radioactivity was measured in whole embryos, cotyledons, and embryonic axes. With either 48-h or 16-d incubation periods, the uptake of (/sup 14/C) ABA depended upon the mode of culture used. The lowest values corresponded to the absorption by the embryonic axis, the highest to the absorption by the distal parts of the two cotyledons. The cotyledons accumulated the main part of the radioactivity under all conditions. Dormant and almost completely after-ripened embryos cultivated for 4 d showed no significant differences in the radioactivity uptake for identical modes of culture. There was a linear relationship between exogenous ABA concentrations (0.5 to 3.10/sup -5/ M) and ABA uptake for embryos cultivated for 4 d with the distal parts of the cotyledons immersed in the medium.

  17. Metabolism of U14C palmitic and 1-14C caproic acids by lettuce seeds during early germination

    International Nuclear Information System (INIS)

    Salon, C.; Raymond, P.; Pradet, A.

    1986-01-01

    Germinating lettuce embryos (before radicule emergence) were fed with either U 14 C palmitic acid or 1 14 C caproic acid until a metabolic steady state was reached. The bulk of labelled caproate was evolved as respiratory CO 2 (52%) and incorporated into organic and amino acids (38%) and only a small part incorporated into lipids whereas most of labelled palmitic acid was found into lipids (92%) and only 8% evolved as CO 2 and incorporated into organic and amino acids. The label distribution at steady state in intermediates linked to the T.C.A. cycle was interpreted using a metabolic model. They found that the two fatty acids were degraded by β-oxidation and incorporated into the T.C.A. cycle as acetylCoA suggesting that β-oxidation is located in the mitochondria. The results also indicate that lipids contribute for at least 90% to the carbon supply to respiration

  18. Autoradiography of [14C]paraquat or [14C]diquat in frogs and mice: accumulation in neuromelanin

    International Nuclear Information System (INIS)

    Lindquist, N.G.; Larsson, B.S.; Lyden-Sokolowski, A.

    1988-01-01

    The herbicide paraquat has been suggested as a causative agent for Parkinson's disease because of its structural similarity to a metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which may induce a parkinsonism-like condition. MPTP as well as its metabolite 1-methyl-4-phenylpyridine have melanin affinity, and the parkinsonism-inducing potency of MPTP is much stronger in species with melanin in the nerve cells. Autoradiography of [ 3 H]MPTP in experimental animals has shown accumulation in melanin-containing tissues, including pigmented neurons. In the present whole body autoradiographic study accumulation and retention was seen in neuromelanin in frogs after i.p. injection of [ 14 C]paraquat or[ 14 C]diquat. By means of whole body autoradiography of [ 14 C]diquat in mice (a species with no or very limited amounts of neuromelanin) a low, relatively uniformly distributed level of radioactivity was observed in brain tissue. Accumulation of toxic chemical compounds, such as paraquat, in neuromelanin may ultimately cause lesions in the pigmented nerve cells, leading to Parkinson's disease

  19. Autoradiography of ( sup 14 C)paraquat or ( sup 14 C)diquat in frogs and mice: accumulation in neuromelanin

    Energy Technology Data Exchange (ETDEWEB)

    Lindquist, N G; Larsson, B S; Lyden-Sokolowski, A [Uppsala Univ., Biomedical Center, (Sweden). Dept. of Toxicology

    1988-10-31

    The herbicide paraquat has been suggested as a causative agent for Parkinson's disease because of its structural similarity to a metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which may induce a parkinsonism-like condition. MPTP as well as its metabolite 1-methyl-4-phenylpyridine have melanin affinity, and the parkinsonism-inducing potency of MPTP is much stronger in species with melanin in the nerve cells. Autoradiography of ({sup 3}H)MPTP in experimental animals has shown accumulation in melanin-containing tissues, including pigmented neurons. In the present whole body autoradiographic study accumulation and retention was seen in neuromelanin in frogs after i.p. injection of ({sup 14}C)paraquat or({sup 14}C)diquat. By means of whole body autoradiography of ({sup 14}C)diquat in mice (a species with no or very limited amounts of neuromelanin) a low, relatively uniformly distributed level of radioactivity was observed in brain tissue. Accumulation of toxic chemical compounds, such as paraquat, in neuromelanin may ultimately cause lesions in the pigmented nerve cells, leading to Parkinson's disease.

  20. Plasma, cerebrospinal fluid, and brain distribution of 14C-melatonin in rat: a biochemical and autoradiographic study

    International Nuclear Information System (INIS)

    Vitte, P.A.; Harthe, C.; Lestage, P.; Claustrat, B.; Bobillier, P.

    1988-01-01

    The distribution of 14C-Melatonin (14C-MT) after systemic injection was studied in the plasma, cerebrospinal fluid (CSF), and brain of rats. Chromatographic analysis (thin-layer chromatography and high-performance liquid chromatography) indicated that the radioactivity from biological samples taken at various times following the injection of label was mainly associated with 14C-MT. Computer analysis of plasma 14C-MT kinetics showed a three-compartment system with half-lives of 0.21 +/- 0.05, 5.97 +/- 1.11, and 47.52 +/- 8.86 min. The volume of distribution and the clearance were 1,736 +/- 349 ml.kg-1 and 25.1 +/- 1.7 ml.min-1.kg-1 respectively. The entry of 14C-MT into the CSF was rapid and reached a maximum at 5 min. The decay followed a two-compartment system with half-lives of 16.5 +/- 2.9 and 47.3 +/- 8.6 min. The CSF/plasma concentration ratio was 0.38 at the steady state (30 min). At 2 min the level of 14C-MT in the brain was 3.8 higher than in the CSF. Representative autoradiograms revealed an heterogeneous localization of 14C-MT in the grey matter. The highest regional values, as evaluated by the permeability area product technique, were found in cortex, thalamic nuclei, medial geniculate nucleus, anterior pretectal area, paraventricular nucleus of the hypothalamus, choroid plexuses, and bulb-pons. Thirty minutes later 14C-MT was still detected in most of the brain regions analyzed. These results point to a low but rapid penetration of circulating MT into the brain and the CSF. The heterogeneous distribution and the partial retention of 14C-MT in the brain are compatible with the hypothesis of a central action of this hormone mediated via binding sites

  1. Metabolism of [14C]indole-3-acetic acid by the cortical and stelar tissues of Zea mays L. roots

    International Nuclear Information System (INIS)

    Nonhebel, H.M.; Hillman, J.R.; Crozier, A.; Wilkins, M.B.

    1985-01-01

    Reverse-phase high-performance liquid chromatography was used to analyse 14 C-labelled metabolites of idole-3-acetic acid (IAA) formed in the cortical and stelar tissues of Zea mays roots. After a 2-h incubation in [ 14 C]IAA, stelar segments had metabolised between 1-6% of the methanol-extractable radioactivity compared with 91-92% by the cortical segments. The pattern of metabolites produced by cortical segments was similar to that produced by intact segments bathed in aqueous solutions of [ 14 C]IAA. In contrast, when IAA was supplied in agar blocks to stelar tissue protruding from the basal ends of segments, negligible metabolism was evident. On the basis of its retention characteristics both before and after methylation, the major metabolite of [ 14 C]IAA in Zea mays root segments was tentatively identified by high-performance liquid chromatography as oxindole-3-acetic acid. (orig.)

  2. Practical synthesis of 14C S-ribosyl-L-homocysteine uniformly labelled on the sugar moiety. An enzymatic route from (U-14C) adenosine

    International Nuclear Information System (INIS)

    Guillerm, G.; Allart, B.

    1992-01-01

    [(U- 14 C) S-Ribosyl]-L-homocysteine has been prepared enzymatically from (U- 14 C) adenosine in two steps using S-adenosyl homocysteine hydrolase and bacterial S-adenosyl homocysteine nucleosidase as catalysts. (Author)

  3. A study of the reactions 14C( vector d, dprime)14C and 14C ( vector d, p)15C at 16.0 MeV

    International Nuclear Information System (INIS)

    Murillo, G.; Sen, S.; Darden, S.E.

    1994-01-01

    Cross-section and vector-analyzing-power measurements for 14 C(d, d prime) and 14 C(d, p) reactions have been carried out for E d =16 MeV. The inelastic-scattering data have been analyzed using the DWBA with a collective and a microscopic model form-factor and also by using the coupled-channels formalism with a vibrational model form-factor. It is observed that while the cross-section angular-distribution data for the two 2 + states at E x =7.012 and 8.318 MeV are very similar, the corresponding vector analyzing powers are quite different. The results of the analyses indicate that the distinctive characteristics probably arise from the difference in the relative importance of the proton and neutron components in the transition amplitude. The 3 - state at E x =6.728 MeV is identified as predominantly a 1p-3h state. Although the deformation parameters are relatively large, the single-particle structure aspects play a more dominant role than channel-coupling effects in populating the inelastic states. The transfer reaction data have been analyzed using the DWBA for bound and unbound states. The importance of two-step processes has been investigated via coupled-reaction-channels calculations. The g.s. and the states with excitation energies 0.770, 3.103 and 4.78 MeV in 15 C are populated primarily by a one-step process with a small two-step contribution in the case of the 3.103 MeV state. The 4.22 MeV state is populated predominantly by two-step processes. The 4.78 and the 5.83 MeV states have been identified as 1p-2h and 3p-4h, [3]/[2] + state, respectively, in an earlier report. There is close similarity in the level structures and reaction mechanisms between the states of 15 C and 17 O populated via the (d, p) reaction. ((orig.))

  4. Highly sensitive detection of a current ripple

    International Nuclear Information System (INIS)

    Aoki, Takashi; Gushiken, Tutomu; Nishikigouri, Kazutaka; Kumada, Masayuki.

    1996-01-01

    In the HIMAC, there are six thyristor-controlled power sources for driving two synchrotrons. These power sources are the three-output terminal power sources which are equipped with positive output, negative output and neutral point for the common mode countermeasures. As electromagnet circuits are connected to the three-output terminal power sources, those are three-line type. In the inside of the power source circuits controlled by thyristors, there is the oscillation peculiar to the power sources, and the variation of voltage induces current spikes. This time, in order to assess the results of the common mode countermeasures in the power source and electromagnet circuits, as one method of cross-check, it is considered that since electromagnet current flows being divided to the bridging resistance and the coil, if attention is paid to the current on bridging resistance side, the ripple components of common mode and normal mode can be detected with high sensitivity, and this was verified. The present state of heightening the performance of synchrotron power sources is explained. The cross-check of the method of assessing the performance of electromagnet power sources is reported. The method of measuring ripple current and the results of the measurement are reported. (K.I.)

  5. Development of high sensitivity radon detectors

    CERN Document Server

    Takeuchi, Y; Kajita, T; Tasaka, S; Hori, H; Nemoto, M; Okazawa, H

    1999-01-01

    High sensitivity detectors for radon in air and in water have been developed. We use electrostatic collection and a PIN photodiode for these detectors. Calibration systems have been also constructed to obtain collection factors. As a result of the calibration study, the absolute humidity dependence of the radon detector for air is clearly observed in the region less than about 1.6 g/m sup 3. The calibration factors of the radon detector for air are 2.2+-0.2 (counts/day)/(mBq/m sup 3) at 0.08 g/m sup 3 and 0.86+-0.06 (counts/day)/(mBq/m sup 3) at 11 g/m sup 3. The calibration factor of the radon detector for water is 3.6+-0.5 (counts/day)/(mBq/m sup 3). The background level of the radon detector for air is 2.4+-1.3 counts/day. As a result, one standard deviation excess of the signal above the background of the radon detector for air should be possible for 1.4 mBq/m sup 3 in a one-day measurement at 0.08 g/m sup 3.

  6. 14C-Methylenebisphenylisocyanate (14C-MDI). Study of absorption after single dermal and intradermal administration in rats

    International Nuclear Information System (INIS)

    Leibold, E.; Hoffmann, H.D.; Hildebrand, B.

    1999-01-01

    The absorption, distribution and excretion of radioactivity was studied in groups of four male Wistar rats following a single dermal and intradermal administration of 14 C- Methylenebisphenylisocyanate ( 14 C-MDI) at nominal dose levels of 4.0 and 0.4 mg/cm 2 for dermal administration and 0.4 mg/animal for intradermal administration. These dose levels nominally corresponded to 40 and 4.0 mg/animal for dermal administration. Considering the animal weights, dose levels corresponded to about 140 and 14 mg/kg body weight (dermal administration) and 1.4 mg/kg body weight (intradermal administration). In the experiments with dermal administration, animals were exposed for 8 hours and sacrificed 8, 24 or 120 h after beginning of exposure. In the experiment with intradermal administration, animals were sacrificed 120 h after treatment. After dermal administration of 14 C-MDI, mean recoveries of radioactivity from all dose groups were in the range from 97.86 to 108.07% of the total radioactivity administered. Generally, the largest proportion of radioactivity was found at the application site and dressing. The total amount of radioactivity absorbed (including excreta, cage wash, tissues/organs and carcass) increased with increasing sacrifice time. Dermal absorption was very low and quantitatively similar at both dose levels; maximally ca. 0.9 % of the applied radioactivity was absorbed. After intradermal administration of 14 C-MDI, the mean recovery of radioactivity was 100.90 % of the radioactivity administered. The largest proportion of radioactivity was found at the application site. The total amount of radioactivity absorbed (including excreta, cage wash, tissues/organs and carcass) amounted to about 26 % of the radioactivity applied. Irrespective of the mode of administration of 1 4C -MDI, concentrations of radioactivity in tissues and organs generally were below 1 μg Eq/g at 120 h after administration. In summary, the results of this study comparing systemic

  7. Effect of inflammatory serum of 14C-glucosamine incorporation into bone marrow granulocytes in vitro

    International Nuclear Information System (INIS)

    Evans, W.H.; Wilson, S.M.; Torres, A.R.; Peterson, E.A.; Mage, M.G.

    1979-01-01

    As a preliminary approach to developing a biochemical assay for detecting humoral regulators of granulocyte maturation in the normal and inglammatory states, studies were carried out on the effects of normal inflammatory sera on the incorporation of 14 C-glucosamine into the glycoproteins of bone marrow granulocytes in vitro. We observed that, relative to normal serum, inflammatory serum had a marked stimulatory effect on 14 C-glucosamine incorporation into these glycoproteins. This property of inflammatory serum reached a maximum at about 8 h after the initiation of inflammation in vivo and preceded the maximum increase in the mitotic activity of granulocyte precursors in the marrow by 18 h. It was also found that normal serum contains both dialyzable and heat-sensitive nondialyzable factors that inhibit 14 C-glucosamine incorporation into bone marrow granulocytes in vitro. Data are presented which indicate that the stimulatory effect of inflammatory serum is most likely due to a nondialyzable factor which is capable of blocking the effect of the inhibitors present in normal serum. (author)

  8. Synthesis of 1-benzyl-4-[(5,6-dimethoxy[2-14C]-1-indanon)-2-YL]-methylpiperidine hydrochloride (E2020-14C)

    International Nuclear Information System (INIS)

    Iimura, Youichi; Mishima, Mannen; Sugimoto, Hachiro

    1989-01-01

    1-Benzyl-4-[(5,6-dimethoxy[2- 14 C]-1-indanon)-2-yl]-methylpiperidine hydrochloride (E2020- 14 C), and acetylcholinesterase inhibitor for studying the pharmacokinetic profiles of E2020, was synthesized from 5,6-dimethoxy[2- 14 C]-1-indanone as the labelled starting material. (author)

  9. Synthesis of 1-benzyl-4-((5,6-dimethoxy(2- sup 14 C)-1-indanon)-2-YL)-methylpiperidine hydrochloride (E2020- sup 14 C)

    Energy Technology Data Exchange (ETDEWEB)

    Iimura, Youichi; Mishima, Mannen; Sugimoto, Hachiro (Eisai Co., Ltd., Ibaraki (Japan). Tsukuba Research Labs.)

    1989-07-01

    1-Benzyl-4-((5,6-dimethoxy(2-{sup 14}C)-1-indanon)-2-yl)-methylpiperidine hydrochloride (E2020-{sup 14}C), and acetylcholinesterase inhibitor for studying the pharmacokinetic profiles of E2020, was synthesized from 5,6-dimethoxy(2-{sup 14}C)-1-indanone as the labelled starting material. (author).

  10. Combustion synthesis of ceramic matrices for immobilization of 14C

    International Nuclear Information System (INIS)

    Bosc-Rouessac, F.; Marin-Ayral, R.M.; Haidoux, A.; Massoni, N.; Bart, F.

    2008-01-01

    In this study, the use of combustion synthesis for immobilization of 14 C was considered. Ceramic matrices have been prepared by this method using two different devices: one non-conventional with preheating of the samples and the other conventional device where ignition was produced thanks to tungsten filament. These two devices gave rise to different mechanisms of reactions involving different amounts of unreacted carbon graphite inside the matrix. The SHS samples were characterized by using scanning electron microscopy (SEM) and X-ray diffraction (XRD)

  11. Studies on 14C labelled chlorpyrifos in model marine ecosystem

    International Nuclear Information System (INIS)

    Pandit, G.G.; Mohan Rao, A.M.; Kale, S.P.; Murthy, N.B.K.; Raghu, K.

    1997-01-01

    Chlorpyrifos is one of the widely used organophosphorus insecticides in tropical countries. Experiments were conducted with 14 C labelled chlorpyrifos to study the distribution of this compound in model marine ecosystem. Less than 50 per cent of the applied activity remained in water in 24 h. Major portion of the applied chlorpyrifos (about 4.2 % residue per g) accumulated into the clams with sediment containing a maximum of 5 to 6 per cent of applied compound. No degradation of chlorpyrifos was observed in water or sediment samples. However, metabolic products were formed in clams. (author). 4 refs., 3 tabs

  12. The synthesis of 2-14C-N-nitrosothiazolidine

    International Nuclear Information System (INIS)

    Cragin, D.W.; Shibamoto, Takayuki

    1989-01-01

    2- 14 C-N-Nitrosothiazolidine was synthesized with a chemical purity of 99.6%, a radio chemical purity of 99.4%, and an overall yield of 30.7%. Unlabelled N-nitrosothiazolidine, synthesized using the same method, resulted in a purity of 99.85% by capillary GC and 99.7% by HPLC. Analysis of N-nitrosothiazolidine by GC was found to require a low injection port temperature of 160 0 C to prevent denitrosation in the injection port. During the nitrosation of thiazolidine, if the pH was reduced below 4 with hydrochloric acid, ring hydrolysis occurred, and chlorinated disulfide compounds formed. (author)

  13. Chemical radiolabeling of carboxyatractyloside by [14C]acetic anhydride

    International Nuclear Information System (INIS)

    Block, M.R.; Pougeois, R.; Vignais, P.V.

    1980-01-01

    The authors report the synthesis and biological properties of a radiolabeled derivative of CAT obtained with acetylation of the primary alcohol of CAT with radiolabeled acetic anhydride. They also investigate the question of mutual exclusion of CAT and BA for binding to the mitochondrial ADP/ATP carrier in double labeling experiments based on the use of [ 3 H]BA and [ 14 C]Ac-CAT. The results are consistent with the view that the ADP/ATP carrier possesses two separate interacting binding sites for AT (or CAT) and for BA. (Auth.)

  14. Application of 14C to physiological studies of insects

    International Nuclear Information System (INIS)

    Yamashita, Okitsugu

    1977-01-01

    The specificity of insects which has been resolved as a result of using tracers such as 14 C etc. and the metabolic ground of vital condition which is not observed in other biotic groups were discussed. As for carbohydrate metabolism, trehalose metabolism, the relation between formation of polyhydric alcohol and quiescence, and energy production system were mentioned. As for lipid metabolism, mobilization of diglyceride among tissues, purification and properties of diglyceride-carrying lipoprotein, and the physiological action of lipoprotein were cited. The specific metabolisms of insects were summarized from the viewpoints of energy production and its distribution mechanism in vivo. (Ichikawa, K.)

  15. The microdose rapid 14C urea breath test compares well with the original rapid 14 breath test

    International Nuclear Information System (INIS)

    Bellon, M.S.; Bartholomeusz, F.D.L.; Chatterton, B.E.

    2000-01-01

    Full text: The 14 C urea breath test (CUBT) is a sensitive test used in the detection of H. pylori infection. The rapid 14 CUBT using 185 KBq of 14 C urea showed a sensitivity of 100% when tested in 36 patients. The aim of this study was to compare the results of the 14 CUBT performed following the ingestion of 37KBq microdose 14 C urea capsule (Bicapsule, Trimed) with the earlier method which uses 185 KBq 14 C urea. 19 patients (nine female age 21-52 yrs) were studied. All subjects first underwent a 14 CUBT with the microdose capsule and a single 15 minute post ingestion sample. An hour later the test was repeated but with a dose of 185 KBq 14 C urea in liquid form. A normal result was taken as 2 = 0.92). This is shown above. The Rapid 14 CUBT performed following the microdose capsule whilst reducing patient radiation exposure is an accurate test for the detection of H. pylori. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  16. Dissipation of 14C chlorpyrifos in the rhizosphere of rice

    International Nuclear Information System (INIS)

    Sharungbam, Geeta Devi; Kapadnis, B.P.; Deopurkar, R.L.; Kale, S.P.

    2004-01-01

    The root exudates from the plants contribute to the biodegradation of insecticides. Although, different mechanisms have been proposed, there is no clear elucidation of any mechanism. This study investigates the dissipation of an organophosphorus insecticide, chlorpyrifos in the rhizospheric soil planted with rice plant. Two sets of experimental tanks were maintained with or without plants using soil spiked with 1 mg kg -1 and 10 mg kg -1 of chlorpyrifos. Experiment was conducted for 180 days till the rice plant starts bearing seeds. The 14 C activity decreased rapidly in the rhizospheric soil as compare to the non-rhizospheric soil. The total culturable microflora were higher in the rhizospheric than the non-rhizospheric soil. The plant extract had given few counts indicating some negligible amount of chlorpyrifos uptake. The 14 C activity in the water was disappeared after 30 days. It was observed that very low amount of residue persisted in soil. This studies revealed that the plants play an important role in the dissipation of the chlorpyrifos from the rice flooded rhizospheric soil. (author)

  17. Strategy of valid 14C dates choice in syngenetic permafrost

    Science.gov (United States)

    Vasil'chuk, Y. K.; Vasil'chuk, A. C.

    2014-11-01

    The main problem of radiocarbon dating within permafrost is the uncertain reliability of the 14C dates. Syngenetic sediments contain allochthonous organic deposit that originated at a distance from its present position. Due to the very good preservation of organic materials in permafrost conditions and numerous re-burials of the fossils from ancient deposits into younger ones the dates could be both younger and older than the true age of dated material. The strategy for the most authentic radiocarbon date selection for dating of syncryogenic sediments is considered taking into account the fluvial origin of the syngenetic sediments. The re-deposition of organic material is discussed in terms of cyclic syncryogenic sedimentation and also the possible re-deposition of organic material in subaerial-subaqueous conditions. The advantages and the complications of dating organic micro-inclusions from ice wedges by the accelerator mass spectrometry (AMS) method are discussed applying to true age of dated material search. Radiocarbon dates of different organic materials from the same samples are compared. The younger age of the yedoma from cross-sections of Duvanny Yar in Kolyma River and Mamontova Khayata in the mouth of Lena River is substantiated due to the principle of the choice of the youngest 14C date from the set.

  18. AMS 14C measurements for tree-ring samples from Japanese woods from 4c AD to 8c AD

    International Nuclear Information System (INIS)

    Ozaki, Hiromasa; Sakamoto, Minoru; Imamura, Mineo; Mitsutani, Takumi

    2010-01-01

    Regional offsets of atmospheric 14 C concentration, as represented by differences from IntCal calibration datasets, are discussed at times in relation to universal use of international radiocarbon calibration curve. In the construction of IntCal, 14 C contents of contemporaneous tree-ring samples from different regions in the northern hemisphere have been used, because the regional differences were indistinguishable from errors of measurements. Nowadays, high-precision 14 C results can be obtained much more easily than before, so more attention should be paid to the possible regional offsets. Most parts of IntCal has been constructed by using 14 C contents of tree-ring samples from woods in high latitude of Europe and North America, which are farthest from Japan in the northern hemisphere. So far, we have measured 14 C contents of tree-ring samples from Japanese wood samples dendrochronologically dated from 11th century BC to 4th century AD in order to investigate regional offset in Japan. Although the obtained results agreed well with IntCal in general, there were some periods when the 14 C contents differ significantly from IntCal. In this paper, we report the new results of AMS 14 C measurement for Japanese tree-ring samples ranging from 4th century AD to 8th century AD. The results show a significant disagreement with IntCal at around 630 AD. Similar difference was indicated by 14 C contents of tree-ring samples from other Japanese woods (Imamura et al., 2007). So it is certain that the regional offset in Japan exists at around 630 AD. (author)

  19. The radioactivity estimation of 14C and 3H in graphite waste samples of the KRR-2.

    Science.gov (United States)

    Reyoung Kim, Hee

    2013-09-01

    The radioactivity of (14)C and (3)H in graphite samples from the dismantled Korea Research Reactor-2 (the KRR-2) site was analyzed by high-temperature oxidation and liquid scintillation counting, and the graphite waste was suggested to be disposed of as a low-level radioactive waste. The graphite samples were oxidized at a high temperature of 800 °C, and their counting rates were measured by using a liquid scintillation counter (LSC). The combustion ratio of the graphite was about 99% on the sample with a maximum weight of 1g. The recoveries from the combustion furnace were around 100% and 90% in (14)C and (3)H, respectively. The minimum detectable activity was 0.04-0.05 Bq/g for the (14)C and 0.13-0.15 Bq/g for the (3)H at the same background counting time. The activity of (14)C was higher than that of (3)H over all samples with the activity ratios of the (14)C to (3)H, (14)C/(3)H, being between 2.8 and 25. The dose calculation was carried out from its radioactivity analysis results. The dose estimation gave a higher annual dose than the domestic legal limit for a clearance. It was thought that the sampled graphite waste from the dismantled research reactor was not available for reuse or recycling and should be monitored as low-level radioactive waste. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. A novel stereospecific synthesis of 14C labeled 1-glutamic acid

    International Nuclear Information System (INIS)

    Wurz, R.E.; Kepner, R.E.; Webb, A.D.

    1989-01-01

    A stereospecific synthesis of 4- 14 C-1-glutamic acid was completed in five steps from sodium 2- 14 C-acetate. The morpholine derived enamine of ethyl pyruvate was reacted with ethyl 2- 14 C-bromoacetate to give after hydrolysis diethyl 4- 14 C-2-oxoglutarate. The 2-oxoglutarate was reacted with hydroxylamine hydrochloride to give diethyl 4-14C-2-hydroxyiminoglutarate which was then reduced with a LiAlH4, (-)-N-methylephedrine and 3,5-dimethylphenol mixture to give 4- 14 C-1-glutamic acid. The 4- 14 C-1-glutamic acid was used in investigations into the biosynthesis of gamma-lactones in sherries

  1. Optimal estimation of atmospheric {sup 14}C production over the Holocene: paleoclimate implications

    Energy Technology Data Exchange (ETDEWEB)

    Marchal, Olivier [Woods Hole Oceanographic Institution, Department of Geology and Geophysics, Woods Hole, MA (United States)

    2005-01-01

    A tree-ring {delta}{sup 14}C record and a simple box model of the global {sup 14}C cycle are combined using a method of optimal estimation theory (Rauch-Tung-Striebel smoother). The combination is used to infer information about the time evolution of {sup 14}C production in the atmosphere (P) for the period 9400 year BCto AD1900 year. Unlike previous attempts to infer P changes from the tree-ring record, the errors in both the {delta}{sup 14}C data and the model, which are assumed to be purely random (not systematic), are formally considered. The optimal time evolution of P is compared to independent evidence of changes in cosmogenic nuclide production over the Holocene from a variety of records on their original chronology, e.g., a record of the virtual axial dipole moment (VADM) based on a compilation of archeomagnetic data, the record of {sup 10}Be concentration from the GISP2 ice core (Central Greenland), and the record of {sup 10}Be concentration from the PS1 ice core (South Pole). The rank correlations between P - VADM,P - {sup 10}Be(GISP2), and P - {sup 10}Be(PS1) are highly significant (p< 0.01), indicating that geomagnetic field intensity and {sup 10}Be concentration in GISP2 and PS1 changed monotonically with {sup 14}C production. The linear correlation coefficients between P - VADM,P - {sup 10}Be(GISP2), and P - {sup 10}Be(PS1) are also highly significant (p<0.01) but relatively small (-0.76, 0.48, and 0.60, respectively). Thus, an important fraction (42-77%) of the variance in the geomagnetic and {sup 10}Be data is not accounted for by linear regression on the {sup 14}C productions implied by the tree-ring record. The P variance near the 1500 yr period, which previous authors interpreted as solar variability, represents a small fraction of the total variance in the P time series (<15% for the band 1200-1800 yr) and does not correspond to a spectral peak. Hence, the hypothesis of a direct solar forcing mechanism for the postulated millennial climate

  2. High sensitivity MOSFET-based neutron dosimetry

    International Nuclear Information System (INIS)

    Fragopoulou, M.; Konstantakos, V.; Zamani, M.; Siskos, S.; Laopoulos, T.; Sarrabayrouse, G.

    2010-01-01

    A new dosemeter based on a metal-oxide-semiconductor field effect transistor sensitive to both neutrons and gamma radiation was manufactured at LAAS-CNRS Laboratory, Toulouse, France. In order to be used for neutron dosimetry, a thin film of lithium fluoride was deposited on the surface of the gate of the device. The characteristics of the dosemeter, such as the dependence of its response to neutron dose and dose rate, were investigated. The studied dosemeter was very sensitive to gamma rays compared to other dosemeters proposed in the literature. Its response in thermal neutrons was found to be much higher than in fast neutrons and gamma rays.

  3. Synthesis of organic substances labelled with 14C and 35S

    International Nuclear Information System (INIS)

    Pichat, L.

    1958-01-01

    After a brief history of the development of the Section des Molecules marquees of the French Atomic Energy Commission, the author gives an outline of the synthesis of the following labelled compounds: benzene 14 C-6; phenyl-p-fluorophenyl, thienyl-2 β alanines β 14 C; noradrenaline β 14 C (arterenol β 14 C), dotriacontane 14 C-16-17, aminoethane sulfinic acid (hypotaurine 35 S). (author) [fr

  4. Measurements of natural levels of 14C in human's and rat's tissues by accelerator mass spectrometry in Korea

    International Nuclear Information System (INIS)

    Cho, S.Y.; Khu, H.J.; Kang, J.H.; Yoon, M.Y.; Kim, J.C.

    2005-01-01

    Accelerator mass spectrometry (AMS) is the most sensitive, safe and precise analytical method for quantifying long-lived isotope in biomedical research with animals as well as human beings. In Korea, AMS Laboratory has been operating successfully for years measuring especially archaeological samples for 14 C dating. In this year, a biological sample pretreatment facility was setup to work on biomedical applications. As a preliminary study, we have measured the natural background levels of 14 C in tissues and blood of humans and rats have been measured. The results were agreed with the other reported levels and gave stable and reproducible results within 1-2%. (author)

  5. Environmental Sensitivity in Children: Development of the Highly Sensitive Child Scale and Identification of Sensitivity Groups

    Science.gov (United States)

    Pluess, Michael; Assary, Elham; Lionetti, Francesca; Lester, Kathryn J.; Krapohl, Eva; Aron, Elaine N.; Aron, Arthur

    2018-01-01

    A large number of studies document that children differ in the degree they are shaped by their developmental context with some being more sensitive to environmental influences than others. Multiple theories suggest that "Environmental Sensitivity" is a common trait predicting the response to negative as well as positive exposures.…

  6. High sensitivity optical measurement of skin gloss

    NARCIS (Netherlands)

    Ezerskaia, A.; Ras, Arno; Bloemen, Pascal; Pereira, S.F.; Urbach, Paul; Varghese, Babu

    2017-01-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between

  7. Comparison of [{sup 18}F]FHBG and [{sup 14}C]FIAU for imaging of HSV1-tk reporter gene expression: adenoviral infection vs stable transfection

    Energy Technology Data Exchange (ETDEWEB)

    Min, Jung-Jun; Iyer, Meera [The Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, UCLA School of Medicine, B3-399A BRI 700 Westwood Plaza, CA 90095-1770, Los Angeles (United States); Gambhir, Sanjiv S. [The Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, UCLA School of Medicine, B3-399A BRI 700 Westwood Plaza, CA 90095-1770, Los Angeles (United States); Department of Radiology, Bio-X Program, Stanford University, Stanford, California (United States)

    2003-11-01

    Earlier studies involving comparison of different reporter probes have shown conflicting results between pyrimidine nucleosides [e.g., 2'-fluoro-2'-deoxy-1-{beta}-d-arabinofuranosyl-5-iodouracil (FIAU)] and acycloguanosine derivatives [e.g., penciclovir (PCV), 9-(4-fluoro-3-hydroxymethylbutyl)guanine (FHBG)]. We hypothesized that this reported discrepancy may be related to how the reporter gene is delivered to the cells - stably transfected vs adenoviral infection. We directly compared the uptake characteristics of [{sup 18}F]FHBG, [{sup 3}H]PCV, and [{sup 14}C]FIAU in cell culture and in vivo using an adenoviral mediated gene transfer model and stably transfected cells. We further compared the uptake of three reporter probes using both HSV1-tk and a mutant HSV1-sr39tk expressing cells to assess the optimal reporter probe/reporter gene combination. [{sup 14}C]FIAU accumulation was greater than that of [{sup 3}H]PCV and [{sup 18}F]FHBG in control cells and in HSV1-tk stably transfected cells (P<0.001). After infection of C6 cells with AdCMV-HSV1-tk (1.5 x 10{sup 8} pfu), [{sup 18}F]FHBG and [{sup 3}H]PCV accumulation was significantly greater than that of [{sup 14}C]FIAU (P<0.01). [{sup 18}F]FHBG and [{sup 3}H]PCV accumulated to a significantly greater extent than [{sup 14}C]FIAU in C6-stb-sr39tk+ and AdCMV-HSV1-sr39tk infected C6 cells (P<0.001). Results from the nude mice supported the results in cell culture. [{sup 14}C]FIAU led to significantly higher %ID/g in C6-stb-tk+ xenografts than [{sup 18}F]FHBG (P<0.05); however, compared with [{sup 14}C]FIAU, [{sup 18}F]FHBG led to as high %ID/g in HSV1-tk expressing hepatocytes and to significantly greater %ID/g in C6-stb-sr39tk+ xenografts and HSV1-sr39tk expressing hepatocytes. Dynamic sequential images showed that [{sup 18}F]FHBG was well retained in HSV1-sr39tk expressing cells (C6-stb-sr39tk+) for at least 4 h after injection, while it was rapidly cleared from HSV1-tk expressing cells (MH3924A

  8. Preparation and HPLC isolation of L-[U-14C]tryptophan from enzyme hydrolysate labelled with 14C

    International Nuclear Information System (INIS)

    Novak, J.; Tintera, S.; Hromadkova, B.

    1990-01-01

    Tryptophan was obtained from biomass of the blue-green alga Synechococcus elongatus cultivated under 14 CO 2 . After partial purification, the protein fraction was subjected to enzymatic hydrolysis using pronase. Semipreparative isolation of L-[U- 14 C]tryptophan was accomplished on a HPLC column of Separon S Hema 1000 CM, 2% ethanol were added to the eluent, and a precolumn packed with the basic anion exchanger Spheron 1000 DEAE was used. Always after the passage of L-[U- 14 C]tryptophan, the precolumn was decoupled. The substance was collected in 96% ethanol. After removing the solvent by vacuum evaporation, the sample was analyzed on a column packed with Separon SIX C 18 in the eluent of 0.1M-NaH 2 PO 4 , 2% methanol. When the desired radiochemical purity was not attained, the sample was purified on Separon SIX C 18 using 2% methanol. The final radiochemical purity achieved by using this method is 98%. (P.A.). 5 figs., 2 tabs., 4 refs

  9. Distribution of 14C in soil and rice plants following application of 14C - parathion to soil

    International Nuclear Information System (INIS)

    Andrea, M.M. de; Ruegg, E.F.

    1983-01-01

    Amount of residues of 14 C-parathion in soil rice plants after application of the insecticide to soil were determined in four systems studied during five weeks: pots of soil with and without plants and open or enclosed by a transparent cover. Measurements of amounts volatilized and 14 CO 2 evolution from the pesticide were made in closed system without plants. The bound residues in soil and plants were also determined. Results indicated that parathion half life in a Gley Humic soil was about two weeks. Very little radiocarbon was taken up by rice plants; of this, more was found in shoots of plants enclosed, probably by collection of the volatilized material by plants. About 6% and 4% of the 14 C-parathion were found as volatilized material and 14 CO 2 , respectively after five weeks. Bound residues varied very little and reached a maximum of 22% in soil and in plants amounted to less than 2% at the final of the experiment. (Author) [pt

  10. Tissue uptake, distribution and elimination of {sup 14}C-PFOA in zebrafish (Danio rerio)

    Energy Technology Data Exchange (ETDEWEB)

    Ulhaq, Mazhar [Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala (Sweden); Sundström, Maria [Environmental Chemistry Unit, Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden); Larsson, Pia; Gabrielsson, Johan [Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala (Sweden); Bergman, Åke [Environmental Chemistry Unit, Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm (Sweden); Norrgren, Leif [Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala (Sweden); Örn, Stefan, E-mail: Stefan.Orn@slu.se [Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala (Sweden)

    2015-06-15

    Highlights: • Bioconcentration of PFOA at steady-state was approximately 20–30 times. • High concentrations were observed in bile and intestines implying enterohepatic circulation. • PFOA accumulated in oocytes indicating maternal transfer. - Abstract: Perfluorooctanoic acid (PFOA) is a long-chain perfluorinated chemical that has been shown to be non-degradable and persistent in the environment. Laboratory studies on bioconcentration and compound-specific tissue distribution in fish can be valuable for prediction of the persistence and environmental effects of the chemicals. In the present study male and female zebrafish (Danio rerio) were continuously exposed to 10 μg/L of radiolabeled perfluorooctanoic acid ({sup 14}C-PFOA) for 40 days, after which the exposed fish were transferred to fresh clean water for another 80 days wash-out period. At defined periodic intervals during the uptake and wash-out, fish were sampled for liquid scintillation counting and whole body autoradiography to profile the bioconcentration and tissue distribution of PFOA. The steady-state concentration of {sup 14}C-PFOA in the zebrafish was reached within 20–30 days of exposure. The concentration-time course of {sup 14}C-PFOA displayed a bi-exponential decline during washout, with a terminal half-life of approximately 13–14 days. At steady-state the bioconcentration of {sup 14}C-PFOA into whole-body fish was approximately 20–30 times greater than that of the exposure concentration, with no differences between females and males. The bioconcentration factors for liver and intestine were approximately 100-fold of the exposure medium, while in brain, ovary and gall bladder the accumulation factors were in the range 15–20. Whole-body autoradiograms confirmed the highest labeling of PFOA in bile and intestines, which implies enterohepatic circulation of PFOA. The {sup 14}C-PFOA was also observed in maturing vitellogenic oocytes, suggesting chemical accumulation via yolk proteins

  11. Long Term Behaviour of 14C and Stability Assessments of Graphite Under Repository Conditions

    International Nuclear Information System (INIS)

    Jones, Abbie N.; McDermott, Lorraine; Worth, Robert; Hagos, Bereket; Black, Greg; Marsden, Barry J

    2016-01-01

    The key objectives of the University of Manchester’s nuclear graphite research within the CRP are to provide analysis on the long term behaviour and stability assessments of irradiated graphite waste. The research will concentrate on isotopic 14 C mobility under repository environments. This also requires an understanding the long-term behaviour of the final waste form under repository conditions. Procedures to evaluate the long term leaching properties of radionuclides from irradiated graphite waste has been developed by combining ANSI 16.1 (USA) and NEN 7345 (Netherlands) standardised diffusion leaching techniques. The ANSI 16.1 standard has been followed to acquire the leachates and to determine the leach rate and diffusion coefficient. The NEN 7345 standard technique has been used to determine the diffusion mechanism of radionuclides. The investigation employs simulated Drigg groundwater as a leachant using semi-dynamic technique for the production of leachate specimens. Analysis of 3 H and 14 C activity release from Magnox graphite was measured using liquid scintillating counting. Preliminary results show that there is an initial high release of activity and decreases when the leaching period increases. This may be due to the depletion of contaminants that were initially bound by the internal pore networks and the free surface. During the leaching test approximately 275.33 ± 18.20 Bq of 3 H and 106.26 ± 7.01 Bq of 14 C was released into the leachant within 91 days. The work reported herein contributed several key findings to the international work on graphite leaching to offer guidance leading toward obtaining leaching data in the future: (a) the effective diffusion coefficient for 14 C from graphite waste has been determined. The diffusion process for 14 C has two stages resulting two different values of diffusion coefficient, i.e., for the fast and slow components; (b) the controlling leaching mechanism for 3 H radionuclide from graphite is shown to be

  12. A two emulsion autoradiographic technique and the discriminating of the three different types of labelling after double labelling with 3H- and 14C-thymidine

    International Nuclear Information System (INIS)

    Schultze, B.; Maurer, W.; Hagenbusch, H.

    1976-01-01

    The first part of the paper deals with a two emulsion autoradiographic technique for double labelling experiments with 3 H- and 14 C-thymidine which permits a clear discrimination of the different types of labelling. In the second part the application of this technique to cell kinetics studies is discussed. Accurate discrimination between the different types of labelling, namely purely 3 H-, purely 14 C- and double ( 3 H + 14 C) labelling, is only possible if the activity ratio of 3 H- to 14 C-thymidine is sufficiently high. This condition is necessary for a reliable distinction between those grains in the first emulsion which are due to true 3 H-labelling and spurious grains which are simultaneously produced in the same emulsion by 14 C-β- particles. Experiments are described to determine the required activity ratio of 3 H- to 14 C-thymidine. (author)

  13. Persistence and mobility of the 14C-DDT organic chlorine insecticide in soil

    International Nuclear Information System (INIS)

    Andrea, M.M. de; Ruegg, E.F.; Tomita, R.Y.

    1988-01-01

    Data from temperate regions considered DDT as highly persistent. This experiment was set to study what is occurring with DDT residues under the Brazilian tropical environment. Tests with 14 C-DDT are being conducted in soil columns in the field, and in the laboratory at ambient temperature and at 34 0 C. It will cover a two years period. Quantification of 14 C is done by liquid scintillation counting of the organic extracts and 14 CO 2 from wet-combustion. Results up to 9 months show that disappearance of the compound is enhanced in the field, and even after 6 months very little amounts of the insecticide leached to the deeper sections of the soils columns. (author) [pt

  14. Uptake, transport and persistence of 14C yeast mannans in plants

    International Nuclear Information System (INIS)

    Kovalenko, A.G.; Kluge, S.

    1988-01-01

    Low-molecular branched-chain 14 C-mannan from Candida tropicalis and high-molecular linear 14 C-mannan from Rhodotorula rubra are not taken up by intact plants. Mechanical injury of plants is a prerequisite for the uptake and transport of polysaccharides in plant tissues. Mannans injected through the epidermis into the parenchyma of tobacco leaves remain mostly confined to the place of injection or to the respective intercostal field. The presence of dimethyl sulfoxide in the solution stimulates the uptake of mannans through intact roots of tobacco, thorn apple and potato plants. Mannans injected in the intercellular space of the parenchyma tissue of tobacco leaves maintain their polymeric structure for at least five days, which almost corresponds with the duration of their antiviral activity in the plants. These results suggest the antiphytoviral activity in fact to be due to the mannans or to principles stimulated by them rather than to their catabolites. (author)

  15. Preparative isolation of [U-14C]solanesol from 14CO2-chamber grown tobacco

    International Nuclear Information System (INIS)

    Hassam, S.B.

    1985-01-01

    A method for the preparative isolation of [U- 14 C]solanesol from 14 CO 2 -chamber grown tobacco is described. Freeze-dried tobacco leaves were Soxhlet extracted with methylene chloride. Fractionation of the extract by silica gel chromatography yielded crude solanesol. Subsequent purification by normal phase high pressure liquid chromatography yielded [U- 14 C]solanesol with a total activity of 474 μCi, a specific activity of 0.5 mCi/mmol, and a radiochemical purity of 95% as determined by RP-HPLC. The chemical purity was 97% and the chemical identity of the isolated compound was confirmed by co-chromatography with reference material and by mass spectroscopy. (author)

  16. [14C]-Sucrose uptake by guard cell protoplasts of pisum sativum, argenteum mutant

    International Nuclear Information System (INIS)

    Rohrig, K.; Raschke, K.

    1991-01-01

    Guard cells rely on import for their supply with reduced carbon. The authors tested by silicone oil centrifugation the ability of guard cell protoplasts to accumulated [ 14 C]-sucrose. Uptake rates were corrected after measurement of 14 C-sorbitol and 3 H 2 O spaces. Sucrose uptake followed biphasic kinetics, with a high-affinity component below 1 mM external sucrose (apparent K m 0.8 mM at 25C) and a low-affinity nonsaturable component above. Uptake depended on pH (optimum at pH 5.0). Variations in the concentrations of external KCl, CCCP, and valinomycin indicated that about one-half of the sucrose uptake rate could be related to an electrochemical gradient across the plasmalemma. Total uptake rates measured at 5 mM external sucrose seem to be sufficient to replenish emptied plastids with starch within a few hours

  17. Studies of 14C-methamidophos residues and their binding to Costa Rican vegetables and soils

    International Nuclear Information System (INIS)

    Carazo, E.; Constenla, M.A.; Fuentes, G.; Moza, P.N.

    1984-01-01

    Studies of 14 C-methamidophos residues in tomato, lettuce and two soils were made under greenhouse conditions. Residues in tomato fruits were 4.5 ppm 35 days after the last application. Total residues in lettuce were also high and present mainly in the edible leaves (9.7 and 12.8 ppm after 3 and 5 applications of the insecticide, respectively). The non-extractable residues constituted a significant part of the total residues in plant tissues. Recovery of the extractable residues decreased with time more rapidly in a loamy clay than in a clay soil. Bound residue levels were about 8% of the applied 14 C in loamy clay after 10 days. Residues in the clay soil were higher and continued to decline throughout a 65-day period. (author)

  18. Mobility and degradation of 14C-trifluralin in soil

    International Nuclear Information System (INIS)

    Zheng Lin; Wang Fujun

    1993-01-01

    Under laboratory condition, the adsorption, mobility and degradation of 14 C-trifluralin in soil were studied by using radioactive isotopic tracer. The results show that the adsorption of trifluralin in soil is quite strong. The rates of adsorption in soil are 73.89 ∼ 90.66%. The adsorption is significantly affected by the organic matter content of soil. It leaches rather low in Grassy-marsh land black soil containing plentiful organic matter and higher clay content, but quite higher in sand, and is more easily to move down. Under anaerobic condition, degradation of trifluralin in soil is faster. It is derogated by 60.2 ∼ 60.4% in soil extractive state within 30 days, and by 90.0 ∼ 94.7% within 60 days. Its main metabolites are the compounds with R f 0.06, 0.15 and 0.42 respectively

  19. Decomposition of 14C - malathion in three Brazilian soil samples

    International Nuclear Information System (INIS)

    Helene, C.G.; Ruegg, E.F.

    1982-01-01

    The degradation of 14 C-malathion in soil was examined using gas chromatography and radiotracer techniques. About half of the malathion added was degraded within a day in soil from three regions of Brazil. Almost all the radiolabelled material extracted from the Red Latosol (Londrina, PR) was malathion, but metabolites were extracted from the 'Sandy' cerrado soil (Planaltina, DF) and Dark-Red Latosol (Passo Fundo, RS). The proportion of metabolites in the extracts increased until most of the malathion was degraded, after four days. Radiocarbon dioxide was liberated from all three soils at similar rates. When about half of the label had been recovered as carbon dioxide after eight weeks, the rate of evolution diminished. (Author) [pt

  20. Synthesis of CH3CH2Br - 14C-1

    International Nuclear Information System (INIS)

    Wolff, R.E.; Pichat, L.

    1958-01-01

    The synthesis of ethyl bromide labelled with 14 C, starting from ethanol, has already been studied: 1- by TOLBERT, CHRISTENSON, NAI-HSUAN and SAH; 2- by SIXMA and HENDRIKS. After various blank tests of these two methods, we have finally obtained the best yields by treating the ethanol with a mixture of 40 per cent hydrobromic acid and concentrated sulphuric acid, in the apparatus normally used in the laboratory for the synthesis of CH 3 I slightly modified, so that the current of nitrogen carrying ethyl bromide and hydrobromic acid passes through a sintered glass disc before being bubbled through a solution of NaOH. We describe here the practical process used for the blank test which gave the best yield (91 per cent) and the active synthesis. (author) [fr

  1. 14C-Profenofos Residues in Milk and Milk Products

    International Nuclear Information System (INIS)

    Fakhr, I.M.I.; Afifi, L.M.; Fouzy, A.S.M.; Hegazi, B.

    1999-01-01

    Treatment of lactating goats with only one dose of 14 C-ethoxy profenofos (17.9 mg/Kg) in gelatin capsules and then feeding normally, resulted in the presence of 0.5% of the radioactive insecticide residues in the milk collected through the fourteen successive days. The highest activity level was depicted at the first day and almost disappeared after two weeks. After processing, the analysis of milk products revealed difference in radioactive residue level according to the nature of the product and increased in the order: whey< skim < yoghurt < pasteurized milk < cheese< cream. TLC analysis of milk and milk products revealed the absence of the parent compound and the presence of 4 major metabolites, which were identified by co-chromatography with authentic compounds

  2. Metabolism of 14C-lindane in flooded alluvial soil

    International Nuclear Information System (INIS)

    Siddaramappa, R.; Sethunathan, N.

    1975-01-01

    The effect of rice straw on the persistence of uniformly ring labelled 14 C-lindane in an alluvial soil was investigated under flooded conditions. The residues in the soil were extracted with chloroform-diethyl ether and the radioactivity was measured by liquid scintillation. The radioactivity in the solvent phase decreased more rapidly in amended soil than in unamended soil. Radioautograph of thin layer chromatograms of solvent phase indicated that lindane was readily converted to a breakdown product in both amended and unamended soils. This breakdown product was also formed in both autoclaved and nonautoclaved soils. Rice straw amendment enhanced further decomposition of lindane and its breakdown product. Heat treatment retarded further decomposition of lindane and its breakdown product whereas they were rapidly decomposed in nonautoclaved soil. These studies indicated that in flooded alluvial soil tested, lindane was initially decomposed by a chemical reaction and soil microorganisms appeared to attack the products of the chemical reaction. (author)

  3. The degradation of [14C] parathion in two Brazilian soils

    International Nuclear Information System (INIS)

    Andrea, M.M. de; Lord, K.A.; Bromilow, R.H.; Ruegg, E.F.

    1980-01-01

    Loss of [ 14 C] parathion from two Brazilian soils was studied by measuring the parathion which could be extracted by a mixture of hexane and propanol and the 14 CO 2 evolved. Recovery of unchanged parathion decreased faster in the soil richer in organic matter (soil 1) from which more radiocarbon was evolved as CO 2 than from the soil poorerin organic matter (soil 2). Evolution of CO 2 from soil 1 decreased rapidly when the soil dried out but little effect of moisture content was observed in soil 2. Radiocarbon remaining in the soils was assayed by combustion after 234 days and the total recovered in soil 1 was 95.6% and, in soil 2,78.7%, sufficient to give almost complete recovery from both soils. (Author) [pt

  4. Synthesis of 14C- and 3H-labeled fluoxetine, a selective serotonin uptake inhibitor

    International Nuclear Information System (INIS)

    Robertson, D.W.; Krushinski, J.H.; Wong, D.T.; Kau, D.

    1987-01-01

    Fluoxetine (N-methyl-γ-(4-(trifluoromethyl)phenoxy) benzenepropanamine) is a potent, highly selective serotonin uptake inhibitor that is useful in treating a variety of major psychiatric derangements. We have synthesized this compound in 14 C- and 3 H-labeled forms. The tritium label was introduced in the final step by catalytic dehalogenation of the brominated fluoxetine precursor. Reaction conditions could be controlled such that catalytic hydrogenolysis of the labile C-O benzylic bond was minimized. Following HPLC purification, [ 3 H]-fluoxetine was obtained in a state of high radiochemical purity (98%) and specific activity (20.4 Ci/mmol). The 14 C-label was introduced in the final step via a nucleophilic aromatic substitution reaction between the sodium salt of α-(2-(methylamino)ethyl)benzenemethanol and uniformly ring-labeled p-chlorobenzotrifluoride. Following purification by flash chromatography, [ 14 C]-fluoxetine was obtained in 98.3% radiochemical purity with a specific activity of 5.52 mCi/mmol. (author)

  5. Asymmetric [14C]albumin transport across bullfrog alveolar epithelium

    International Nuclear Information System (INIS)

    Kim, K.J.; LeBon, T.R.; Shinbane, J.S.; Crandall, E.D.

    1985-01-01

    Bullfrog lungs were prepared as planar sheets and bathed with Ringer solution in Ussing chambers. In the presence of a constant electrical gradient (20, 0, or -20 mV) across the tissue, 14 C-labeled bovine serum albumin or inulin was instilled into the upstream reservoir and the rate of appearance of the tracer in the downstream reservoir was monitored. Two lungs from the same animal were used to determine any directional difference in tracer fluxes. An apparent permeability coefficient was estimated from a relationship between normalized downstream radioactivities and time. Results showed that the apparent permeability of albumin in the alveolar to pleural direction across the alveolar epithelial barrier is 2.3 X 10(-7) cm/s, significantly greater (P less than 0.0005) than that in the pleural to alveolar direction (5.3 X 10(-8) cm/s) when the tissue was short circuited. Permeability of inulin, on the other hand, did not show any directional dependence and averaged 3.1 X 10(-8) cm/s in both directions. There was no effect on radiotracer fluxes permeabilities of different electrical gradients across the tissue. Gel electrophoretograms and corresponding radiochromatograms suggest that the large and asymmetric isotope fluxes are not primarily due to digestion or degradation of labeled molecules. Inulin appears to traverse the alveolar epithelial barrier by simple diffusion through hydrated paracellular pathways. On the other hand, [ 14 C]albumin crosses the alveolar epithelium more rapidly than would be expected by simple diffusion. These asymmetric and large tracer fluxes suggest that a specialized mechanism is present in alveolar epithelium that may be capable of helping to remove albumin from the alveolar space

  6. Using 14C and 3H to understand groundwater flow and recharge in an aquifer window

    Science.gov (United States)

    Atkinson, A. P.; Cartwright, I.; Gilfedder, B. S.; Cendón, D. I.; Unland, N. P.; Hofmann, H.

    2014-12-01

    Knowledge of groundwater residence times and recharge locations is vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge from rainfall and recharge from the Gellibrand River. To determine recharge patterns and groundwater flow paths, environmental isotopes (3H, 14C, δ13C, δ18O, δ2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. The water table fluctuates by 0.9 to 3.7 m annually, implying recharge rates of 90 and 372 mm yr-1. However, residence times of shallow (11 to 29 m) groundwater determined by 14C are between 100 and 10 000 years, 3H activities are negligible in most of the groundwater, and groundwater electrical conductivity remains constant over the period of study. Deeper groundwater with older 14C ages has lower δ18O values than younger, shallower groundwater, which is consistent with it being derived from greater altitudes. The combined geochemistry data indicate that local recharge from precipitation within the valley occurs through the aquifer window, however much of the groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High. The Gellibrand Valley is a regional discharge zone with upward head gradients that limits local recharge to the upper 10 m of the aquifer. Additionally, the groundwater head gradients adjacent to the Gellibrand River are generally upwards, implying that it does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10

  7. Kernel abortion in maize. II. Distribution of 14C among kernel carboydrates

    International Nuclear Information System (INIS)

    Hanft, J.M.; Jones, R.J.

    1986-01-01

    This study was designed to compare the uptake and distribution of 14 C among fructose, glucose, sucrose, and starch in the cob, pedicel, and endosperm tissues of maize (Zea mays L.) kernels induced to abort by high temperature with those that develop normally. Kernels cultured in vitro at 309 and 35 0 C were transferred to [ 14 C]sucrose media 10 days after pollination. Kernels cultured at 35 0 C aborted prior to the onset of linear dry matter accumulation. Significant uptake into the cob, pedicel, and endosperm of radioactivity associated with the soluble and starch fractions of the tissues was detected after 24 hours in culture on atlageled media. After 8 days in culture on [ 14 C]sucrose media, 48 and 40% of the radioactivity associated with the cob carbohydrates was found in the reducing sugars at 30 and 35 0 C, respectively. Of the total carbohydrates, a higher percentage of label was associated with sucrose and lower percentage with fructose and glucose in pedicel tissue of kernels cultured at 35 0 C compared to kernels cultured at 30 0 C. These results indicate that sucrose was not cleaved to fructose and glucose as rapidly during the unloading process in the pedicel of kernels induced to abort by high temperature. Kernels cultured at 35 0 C had a much lower proportion of label associated with endosperm starch (29%) than did kernels cultured at 30 0 C (89%). Kernels cultured at 35 0 C had a correspondingly higher proportion of 14 C in endosperm fructose, glucose, and sucrose

  8. Breath 14CO2 after intravenous administration of [14C]aminopyrine in liver diseases

    International Nuclear Information System (INIS)

    Pauwels, S.; Geubel, A.P.; Dive, C.; Beckers, C.

    1982-01-01

    The determination of of 14 CO2 in breath after oral administration of [ 14 C]aminopyrine has been proposed as a quantitative liver function test. In order to shorten the procedure and avoid misinterpretations related to variable rates of intestinal absorption, the [ 14 C]aminopyrine breath test (ABT) was performed after intravenous administration of [ 14 C]aminopyrine in 21 controls and 89 patients with biopsy-proven liver disease. The specific activity of the first hour sample corrected for body weight (SA1) was the most discriminant expression of breath data. The SA1 value, expressed as the percentage of the administered dose, was 0.86 +/- 0.1% (mean +/- SD) in controls and significantly less in patients (0.46 +/- 0.31%). Low values were observed in patients with untreated chronic active hepatitis (0.16 +/- 0.13%), alcoholic cirrhosis (0.2 +/ 0.15%0, and untreated postnecrotic cirrhosis (0.47 +/- 0.17%). In contrast, normal values were obtained in chronic persistent hepatitis (0.86 +/- 0.13%) and 58% of noncirrhotic alcoholic liver diseases (0.83 +/- 0.27%). The results of duplicate studies were reproducible and SA1 correlated with other conventional liver function tests, including 45-min BSP retention. Among these, ABT was the most sensitive screening test for the presence of cirrhosis, especially in alcoholic patients, where it allowed a sharp distinction between cirrhotic and noncirrhotic cases. The results obtained in chronic hepatitis suggested that ABT may provide a reliable index of the activity of the disease. In our hands, intravenous ABT, performed over a 1-hr period, was a fast, sensitive, and discriminant liver function test

  9. XCAMS: The compact 14C accelerator mass spectrometer extended for 10Be and 26Al at GNS Science, New Zealand

    Science.gov (United States)

    Zondervan, A.; Hauser, T. M.; Kaiser, J.; Kitchen, R. L.; Turnbull, J. C.; West, J. G.

    2015-10-01

    A detailed description is given of the 0.5 MV tandem accelerator mass spectrometry (AMS) system for 10Be, 14C, 26Al, installed in early 2010 at GNS Science, New Zealand. Its design follows that of previously commissioned Compact 14C-only AMS (CAMS) systems based on the Pelletron tandem accelerator. The only basic departure from that design is an extension of the rare-isotope achromat with a 45° magnet and a two-anode gas-ionisation detector, to provide additional filtering for 10Be. Realised performance of the three AMS modes is discussed in terms of acceptance-test scores, 14C Poisson and non-Poisson errors, and 10Be detection limit and sensitivity. Operational details and hardware improvements, such as 10Be beam transport and particle detector setup, are highlighted. Statistics of repeat measurements of all graphitised 14C calibration cathodes since start-up show that 91% of their total uncertainty values are less than 0.3%, indicating that the rare-isotope beamline extension has not affected precision of 14C measurement. For 10Be, the limit of detection in terms of the isotopic abundance ratio 10Be/9Be is 6 × 10-15 at at-1 and the total efficiency of counting atoms in the sample cathode is 1/8500 (0.012%).

  10. High sensitivity optical measurement of skin gloss

    OpenAIRE

    Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F.; Urbach, H. Paul; Varghese, Babu

    2017-01-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the...

  11. Accelerator mass spectrometry analysis of 14C-oxaliplatin concentrations in biological samples and 14C contents in biological samples and antineoplastic agents

    Science.gov (United States)

    Toyoguchi, Teiko; Kobayashi, Takeshi; Konno, Noboru; Shiraishi, Tadashi; Kato, Kazuhiro; Tokanai, Fuyuki

    2015-10-01

    Accelerator mass spectrometry (AMS) is expected to play an important role in microdose trials. In this study, we measured the 14C concentration in 14C-oxaliplatin-spiked serum, urine and supernatant of fecal homogenate samples in our Yamagata University (YU) - AMS system. The calibration curves of 14C concentration in serum, urine and supernatant of fecal homogenate were linear (the correlation coefficients were ⩾0.9893), and the precision and accuracy was within the acceptance criteria. To examine a 14C content of water in three vacuum blood collection tubes and a syringe were measured. 14C was not detected from water in these devices. The mean 14C content in urine samples of 6 healthy Japanese volunteers was 0.144 dpm/mL, and the intra-day fluctuation of 14C content in urine from a volunteer was little. The antineoplastic agents are administered to the patients in combination. Then, 14C contents of the antineoplastic agents were quantitated. 14C contents were different among 10 antineoplastic agents; 14C contents of paclitaxel injection and docetaxel hydrate injection were higher than those of the other injections. These results indicate that our quantitation method using YU-AMS system is suited for microdosing studies and that measurement of baseline and co-administered drugs might be necessary for the studies in low concentrations.

  12. Accelerator mass spectrometry analysis of "1"4C-oxaliplatin concentrations in biological samples and "1"4C contents in biological samples and antineoplastic agents

    International Nuclear Information System (INIS)

    Toyoguchi, Teiko; Kobayashi, Takeshi; Konno, Noboru; Shiraishi, Tadashi; Kato, Kazuhiro; Tokanai, Fuyuki

    2015-01-01

    Accelerator mass spectrometry (AMS) is expected to play an important role in microdose trials. In this study, we measured the "1"4C concentration in "1"4C-oxaliplatin-spiked serum, urine and supernatant of fecal homogenate samples in our Yamagata University (YU) – AMS system. The calibration curves of "1"4C concentration in serum, urine and supernatant of fecal homogenate were linear (the correlation coefficients were ⩾0.9893), and the precision and accuracy was within the acceptance criteria. To examine a "1"4C content of water in three vacuum blood collection tubes and a syringe were measured. "1"4C was not detected from water in these devices. The mean "1"4C content in urine samples of 6 healthy Japanese volunteers was 0.144 dpm/mL, and the intra-day fluctuation of "1"4C content in urine from a volunteer was little. The antineoplastic agents are administered to the patients in combination. Then, "1"4C contents of the antineoplastic agents were quantitated. "1"4C contents were different among 10 antineoplastic agents; "1"4C contents of paclitaxel injection and docetaxel hydrate injection were higher than those of the other injections. These results indicate that our quantitation method using YU-AMS system is suited for microdosing studies and that measurement of baseline and co-administered drugs might be necessary for the studies in low concentrations.

  13. Accelerator mass spectrometry analysis of {sup 14}C-oxaliplatin concentrations in biological samples and {sup 14}C contents in biological samples and antineoplastic agents

    Energy Technology Data Exchange (ETDEWEB)

    Toyoguchi, Teiko, E-mail: tteiko@med.id.yamagata-u.ac.jp [Department of Pharmacy, Yamagata University Hospital, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585 (Japan); Kobayashi, Takeshi; Konno, Noboru; Shiraishi, Tadashi [Department of Pharmacy, Yamagata University Hospital, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585 (Japan); Kato, Kazuhiro; Tokanai, Fuyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata-shi, Yamagata 990-8560 (Japan)

    2015-10-15

    Accelerator mass spectrometry (AMS) is expected to play an important role in microdose trials. In this study, we measured the {sup 14}C concentration in {sup 14}C-oxaliplatin-spiked serum, urine and supernatant of fecal homogenate samples in our Yamagata University (YU) – AMS system. The calibration curves of {sup 14}C concentration in serum, urine and supernatant of fecal homogenate were linear (the correlation coefficients were ⩾0.9893), and the precision and accuracy was within the acceptance criteria. To examine a {sup 14}C content of water in three vacuum blood collection tubes and a syringe were measured. {sup 14}C was not detected from water in these devices. The mean {sup 14}C content in urine samples of 6 healthy Japanese volunteers was 0.144 dpm/mL, and the intra-day fluctuation of {sup 14}C content in urine from a volunteer was little. The antineoplastic agents are administered to the patients in combination. Then, {sup 14}C contents of the antineoplastic agents were quantitated. {sup 14}C contents were different among 10 antineoplastic agents; {sup 14}C contents of paclitaxel injection and docetaxel hydrate injection were higher than those of the other injections. These results indicate that our quantitation method using YU-AMS system is suited for microdosing studies and that measurement of baseline and co-administered drugs might be necessary for the studies in low concentrations.

  14. Transfer of {sup 14}C to prenatal and neonatal rats from their mothers exposed to {sup 14}C compounds by ingestion

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, H.; Fuma, S.; Miyamoto, K.; Kuroda, N.; Inaba, J

    2003-07-01

    The transfer of {sup 14}C through placenta or milk was investigated and the radiation dose to fetal and newborn rats was estimated. Female rats at gestational stages or after delivery were exposed to {sup 14}C in the form of sodium bicarbonate, thymidine and lysine by a single ingestion. Radioactivity in maternal tissues and conceptuses (placenta, fetal membrane and fetus) and in the newborn was determined at various times after ingestion. After exposure to these {sup 14}C compounds, there was no significant difference between the {sup 14}C concentration in the fetus and that in the maternal tissues, suggesting that the placenta has no effect in preventing or accelerating the placental transfer of {sup 14}C. The concentration and content of {sup 14}C in the fetus and newborn were, however, dependent on the chemical form of {sup 14}C and on the prenatal or neonatal stage at the time of ingestion. The result of the dose estimation showed that {sup 14}C-lysine gave significantly higher prenatal and neonatal doses than {sup 14}C-sodium bicarbonate or {sup 14}C-thymidine. (author)

  15. Long-term persistence of various 14C-labeled pesticides in soils

    International Nuclear Information System (INIS)

    Jablonowski, Nicolai D.; Linden, Andreas; Köppchen, Stephan; Thiele, Björn; Hofmann, Diana; Mittelstaedt, Werner; Pütz, Thomas; Burauel, Peter

    2012-01-01

    The fate of the 14 C-labeled herbicides ethidimuron (ETD), methabenzthiazuron (MBT), and the fungicide anilazine (ANI) in soils was evaluated after long-term aging (9–17 years) in field based lysimeters subject to crop rotation. Analysis of residual 14 C activity in the soils revealed 19% (ETD soil; 0–10 cm depth), 35% (MBT soil; 0–30), and 43% (ANI soil; 0–30) of the total initially applied. Accelerated solvent extraction yielded 90% (ETD soil), 26% (MBT soil), and 41% (ANI soil) of residual pesticide 14 C activity in the samples. LC-MS/MS analysis revealed the parent compounds ETD and MBT, accounting for 3% and 2% of applied active ingredient in the soil layer, as well as dihydroxy-anilazine as the primary ANI metabolite. The results for ETD and MBT were matching with values obtained from samples of a 12 year old field plot experiment. The data demonstrate the long-term persistence of these pesticides in soils based on outdoor trials. - Highlights: ► The environmental persistence of three 14 C-labeled pesticides in soils is presented. ► Extract analysis revealed the pesticides and metabolites after 9–17 years of aging. ► Pesticide residues may represent a long-term soil burden. ► The bioaccessibility and/or bioavailability of long-term aged pesticide residues remain unknown. - Residual fractions of the pesticides ethidimuron, methabenzthiazuron, and metabolites of anilazine are highly persistent in soils and remain extractable after long-term environmental aging.

  16. Dynamics of {sup 14}C-labeled glucose and ammonium in saline arable soils

    Energy Technology Data Exchange (ETDEWEB)

    Vuelvas-Solorzano, Alma; Hernandez-Matehuala, Rosalina [Instituto Tecnologico de Celaya, Celaya Gto. (Mexico). Dept. de Ing. Bioquimica. Lab. de Bioingenieria; Conde-Barajas, Eloy; Cardenas-Manriquez, Marcela [Instituto Tecnologico de Celaya, Celaya Gto. (Mexico). Dept. de Ing. Ambiental. Lab. de Bioingenieria], e-mail: marcela@itc.mx; Luna-Guido, Marco L.; Dendooven, Luc [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional (Cinvestav), D.F. (Mexico). Dept. de Biotecnologia y Bioingenieria. Lab. de Ecologia de Suelos], e-mail: dendoove@cinvestav.mx

    2009-07-15

    Organic matter dynamics and nutrient availability in saline agricultural soils of the State of Guanajuato might provide information for remediation strategies. {sup 14}C labeled glucose with or without 200 mg kg{sup -}1 of NH{sub 4} {sup +}-N soil was added to two clayey agricultural soils with different electrolytic conductivity (EC), i.e. 0.94 dS m{sup -}1 (low EC; LEC) and 6.72 dS m{sup -}1 (high EC; HEC), to investigate the effect of N availability and salt content on organic material decomposition. Inorganic N dynamics and production of CO{sub 2} and {sup 14}CO{sub 2} were monitored. Approximately 60 % of the glucose-{sup 14}C added to LEC soil evolved as {sup 14}CO{sub 2}, but only 20 % in HEC soil after the incubation period of 21 days. After one day, < 200 mg {sup 14}C was extractable from LEC soil, but > 500 mg {sup 14}C from HEC soil. No N mineralization occurred in the LEC and HEC soils and glucose addition reduced the concentrations of inorganic N in unamended soil and soil amended with NH{sub 4}{sup +}-N. The NO{sub 2}{sup -} and NO{sub 3}{sup -} concentrations were on average higher in LEC than in HEC soil, with exception of NO{sub 2}{sup -} in HEC amended with NH{sub 4}{sup +}-N. It was concluded that increases in soil EC reduced mineralization of the easily decomposable C substrate and resulted in N-depleted soil. (author)

  17. Environment ecological effect of 14C-chlorsulfuron and its safety evaluation

    International Nuclear Information System (INIS)

    Chen Zuyi; Cheng Wei

    1995-12-01

    The adsorption, migration, degradation, residues of 14 C-chlorsulfuron and ecological effects of its degradation products were reviewed by isotope trace technique. The results show that: (1) The adsorption of 14 C-chlorsulfuron in soil are rather weak and its migration are rather strong. (2) The degradation of chlorsulfuron in soils are slow. The bound residues of chlorsulfuron in dry land soil are very considerable and increasing with the incubation time, extractive residues decrease gradually. By means of TLC and radioactive assay the radioactive degradation products of 14 C-chlorsulfuron in soil belong to trinitrogen-aniline. (3) One wheat and rice-wheat seasons after its application, the soil and after-crop (rice) all have considerable residues. The residue of chlorsulfuron and its transfer coefficient are far more than that in its shoots, the latter are more than that in soil. It is not distributed evenly in the plants. The residue in roots is far more than that in plant, which explains clearly that the bad effect of chlorsulfuron on the growth of root is related with its high accumulation on root. (4) The residue products including bound residues of 14 C-chlorsulfuron in soils were available on after-crop (maize, bean, pea, rice and garden sass). The damage symptoms showed that the root system development were clearly suppressed and the seedling were effected on growth. The minimum suffer dose of bound residues is 10 μg/kg in the stage of seedling growth. (19 refs., 8 figs., 8 tabs.)

  18. Translocation kinetics of 14C-photosynthate in hybrid rice grown at different potassium levels

    International Nuclear Information System (INIS)

    Jiang Dean; Shen Yuwei; Xie Xuemin; Rao Lihua; Lu Qing

    1993-01-01

    The kinetics of translocation of 14 C-assimilate in hybrid rice plant was studied with 14 CO 2 fed to functional leaf at the tillering and filling stages. The result indicated that the relationship between percentage (V) of photosynthate exporting out of the source leaf or that of assimilate into sink, expanding young leaf or filling panicle, respectively,and time(t)after introducing 14 CO 2 into the leaf was extremely coincided with the regression equation : v = V (t + k)/K m + (t + k). At the tillering stage, fully extended top leaf could export 66% ∼ 79% of its photosynthate assimilated at different potassium levels, and both export potential and rate of 14 C-photosynthate in the fed leaf decreased under the low potassium (1 ppm K supplied), but the rate obviously increased in the superfluous potassium (80 ppm K supplied) in spite of slightly low exporting capacity. Main sink, the expanding young leaf on the top of stem could obtain 28% ∼ 59% of 14 C-assimilate at various potassium levels. Both the importation potential and rate were lowered with low potassium application while hastened by super-supplied potassium at the same development stage. At the filling stage, source, flag leaf, was able to export 83% ∼ 97% of its photosynthate and low potassium (5 ppm) application not only delayed the time of 14 C-photosynthate exportation but also diminished the export rate, whereas the rate was accelerated by superfluous potassium. Low potassium resulted in decrease both in the capacity and in the rate of assimilate importing into grain, nevertheless, high potassium caused decrease of percentage assimilate importing into grain and the increase of improving rate. Therefore, it was strategically considered that neither deficient nor superfluous potassium application was beneficial for assimilate transportation

  19. Searches for massive neutrino emission in 14C beta and 55Fe electron-capture decays

    International Nuclear Information System (INIS)

    Wietfeldt, F.E.

    1994-05-01

    In 1985 Simpson reported evidence for the emission of a 17 keV mass neutrino in a small fraction of tritium beta decays. An experimental controversy ensued in which a number of both positive and negative results were reported. The beta spectrum of 14 C was collected in a unique 14 C-doped planar germanium detector and a distortion was observed that initially confirmed Simpson's result. Further tests linked this distortion to a splitting of the collected charge between the central detector and the surrounding guard ring in a fraction of the events. A second 14 C measurement showed no evidence for emission of a 17 keV mass neutrino. In a related experiment, a high statistics electron-capture internal-bremsstrahlung photon spectrum of 55 Fe was collected with a coaxial germanium detector. A local search for departures from a smooth shape near the endpoint was performed, using a second-derivative technique. An upper limit of 0.65% (95% C.L.) for the mixing Of a neutrino in the mass range 5--25 keV was established. The upper limit on the mixing of a 17 keV mass neutrino was 0.14% (95% C.L.)

  20. Human urinary excretion profile after smoking and oral administration of [14C]delta 1-tetrahydrocannabinol

    International Nuclear Information System (INIS)

    Johansson, E.; Gillespie, H.K.; Halldin, M.M.

    1990-01-01

    The urinary excretion profiles of delta 1-tetrahydrocannabinol (delta 1-THC) metabolites have been evaluated in two chronic and two naive marijuana users after smoking and oral administration of [ 14 C]delta 1-THC. Urine was collected for five days after each administration route and analyzed for total delta 1-THC metabolites by radioactivity determination, for delta 1-THC-7-oic acid by high-performance liquid chromatography, and for cross-reacting cannabinoids by the EMIT d.a.u. cannabinoid assay. The average urinary excretion half-life of 14 C-labeled delta 1-THC metabolites was calculated to be 18.2 +/- 4.9 h (+/- SD). The excretion profiles of delta 1-THC-7-oic acid and EMIT readings were similar to the excretion profile of 14 C-labeled metabolites in the naive users. However, in the chronic users the excretion profiles of delta 1-THC-7-oic acid and EMIT readings did not resemble the radioactive excretion due to the heavy influence from previous Cannabis use. Between 8-14% of the radioactive dose was recovered in the urine in both user groups after oral administration. Lower urinary recovery was obtained both in the chronic and naive users after smoking--5 and 2%, respectively

  1. Adsorption and desorption of plant growth regulator 14C-PP333 in various soils

    International Nuclear Information System (INIS)

    Yu Fengyi; Zhang Ping; Yang Xiu

    1995-01-01

    Adsorption, desorption and residue of 14 C-PP333 with 4 concentrations in various soils were studied by radioactive isotopic tracer. The results showed that the adsorption rates in 6 soils were different. The lowest adsorption rate of fluvo-aquatic soil from Shanxi was 15.22%, the highest adsorption rate of black soil from Heilongjiang was 22.53%. The relation between the C.E.C., O.M. and adsorption rate in soil was correlative. Adsorption rate in soil increased with an increase in C.E.C.. 14 C-PP3333 adsorbed in 6 soils could be desorbed by water. The desorption rate in soils was high. There is residue of 14 C-PP333 in soil desorbed by water. There was a negative relationship between the residue amount and the adsorption rate in soil. Easy desorption of PP333 adsorbed in soil showed that PP333 was movable and diffusible in soil and had influence on agro-ecosystem

  2. Distribution of 14C-activity among the organic acids in the Satsuma mandarin fruits fed with 14C-compounds

    International Nuclear Information System (INIS)

    Kubota, Shuji; Akao, Shoichiro; Hayashida, Michito.

    1978-01-01

    1. Twenty four hours after 14 CO 2 feeding to the leaves, malic acid had the highest level of total and specific radioactivity among the organic acids extracted from the juice vesicles, and citric acid had the second highest total activity. An unidentified acid compound had a relatively high activity. 2. Pyruvic acid-2- 14 C was fed as a substrate for acid formation to the one young fruit on a shoot, and NaH 14 CO 3 was fed as a source of carbon-dioxide to the other young fruit through the pedicel. After three hours of pyruvic acid feeding, malic acid, citric acid and aspartic acid were the major labelled compounds in the vesicles. Then, a marked increase and redistribution of activity in acids took place with time, and the levels of total and specific activity in citric acid increased steadily. The sorts of labelled compounds into which activity was incorporated from NaH 14 CO 3 were essentially similar to those in pyruvic acid-2- 14 C feeding. 3. These results seem to support the theory that the dark fixation of carbon-dioxide plays an important role in the synthesis of the organic acids in citrus fruit vesicles. (auth.)

  3. High sensitivity optical measurement of skin gloss.

    Science.gov (United States)

    Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F; Urbach, H Paul; Varghese, Babu

    2017-09-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the improved sensitivity of the two proposed methods using Monte Carlo simulations and experiments performed on ISO gloss calibration standards with an optical prototype. The performance and linearity of the method was compared with different professional gloss measurement devices based on the ratio of specular to diffuse intensity. We demonstrate the feasibility for in-vivo skin gloss measurements by quantifying the temporal evolution of skin gloss after application of standard paraffin cream bases on skin. The presented method opens new possibilities in the fields of cosmetology and dermatopharmacology for measuring the skin gloss and resorption kinetics and the pharmacodynamics of various external agents.

  4. A rapid microwave induced synthesis of [carboxyl-14C]-nicotinic acid (vitamin B3) and [carbonyl-14C]-nicotinamide using K14CN

    International Nuclear Information System (INIS)

    Ravi, S.; Mathew, K.M.; Sivaprasad, N.

    2008-01-01

    Microwave assisted direct aromatic substitution of 3-bromopyridine with K 14 CN as the cyanide source and catalytic amount of tetrabutylammonium bromide afforded [3- 14 C]-cyanopyridine 3 in 90% yield. Microwave assisted hydrolysis of 3 with a mixture of concentrated hydrochloric acid and propionic acid afforded [carboxyl- 14 C]-nicotinic acid in 95% yield whereas microwave assisted hydrolysis of 3 with a mixture of concentrated sulfuric acid and propionic acid afforded [carbonyl- 14 C]-nicotinamide in 85% yield. (author)

  5. The Tritiated Water Skin Barrier Integrity Test: Considerations for Acceptance Criteria with and Without 14C-Octanol.

    Science.gov (United States)

    Lehman, Paul A; Beatch, Kacie; Raney, Sam G; Franz, Thomas J

    2017-01-01

    A study was designed to assess barrier integrity simultaneously using separate compounds (probes) for polar and non-polar pathways through the skin, 3 H 2 O and 14 C-octanol, respectively; and to determine whether the two probe approach could better define barrier integrity. A 5-min dose of water containing 3 H 2 O and 14 C -octanol was applied to ex vivo human skin mounted in Franz diffusion cells. The receptor solution was sampled at 30 min, analyzed for 3 H and 14 C content, and the correlation between water and octanol absorption was determined by statistical tests suitable for non-normally distributed data. This study was conducted on skin from 37 donors with from 3 to 30 replicate skin sections per donor (a total of 426 sections). The correlation between 3 H 2 O and 14 C-octanol absorption was low (Pearson correlation coefficient = 0.3485). The 3 H 2 O absorption cutoff used in this study to select for a normal skin barrier rejected some sections in which 14 C-octanol absorption was within normal limits and accepted others in which 14 C-octanol absorption was abnormally high. The converse was true for 3 H 2 O absorption when the 14 C-octanol-based cutoff was used. The results of the 3 H 2 O test or of similar tests that primarily assess the permeability of polar pathways through the skin may not necessarily provide information relevant to the absorption of highly lipophilic compounds. Octanol, or another molecule that more closely matches the physicochemical attributes of the test compound, may characterize properties of the skin barrier that are more relevant to compounds of low water solubility.

  6. The selectively bred high alcohol sensitivity (HAS) and low alcohol sensitivity (LAS) rats differ in sensitivity to nicotine.

    Science.gov (United States)

    de Fiebre, NancyEllen C; Dawson, Ralph; de Fiebre, Christopher M

    2002-06-01

    Studies in rodents selectively bred to differ in alcohol sensitivity have suggested that nicotine and ethanol sensitivities may cosegregate during selective breeding. This suggests that ethanol and nicotine sensitivities may in part be genetically correlated. Male and female high alcohol sensitivity (HAS), control alcohol sensitivity, and low alcohol sensitivity (LAS) rats were tested for nicotine-induced alterations in locomotor activity, body temperature, and seizure activity. Plasma and brain levels of nicotine and its primary metabolite, cotinine, were measured in these animals, as was the binding of [3H]cytisine, [3H]epibatidine, and [125I]alpha-bungarotoxin in eight brain regions. Both replicate HAS lines were more sensitive to nicotine-induced locomotor activity depression than the replicate LAS lines. No consistent HAS/LAS differences were seen on other measures of nicotine sensitivity; however, females were more susceptible to nicotine-induced seizures than males. No HAS/LAS differences in nicotine or cotinine levels were seen, nor were differences seen in the binding of nicotinic ligands. Females had higher levels of plasma cotinine and brain nicotine than males but had lower brain cotinine levels than males. Sensitivity to a specific action of nicotine cosegregates during selective breeding for differential sensitivity to a specific action of ethanol. The differential sensitivity of the HAS/LAS rats is due to differences in central nervous system sensitivity and not to pharmacokinetic differences. The differential central nervous system sensitivity cannot be explained by differences in the numbers of nicotinic receptors labeled in ligand-binding experiments. The apparent genetic correlation between ethanol and nicotine sensitivities suggests that common genes modulate, in part, the actions of both ethanol and nicotine and may explain the frequent coabuse of these agents.

  7. Changes in the level of [14C]indole-3-acetic acid and [14C]indoleacetylaspartic acid during root formation in mung bean cuttings

    International Nuclear Information System (INIS)

    Norcini, J.G.; Heuser, C.W.

    1988-01-01

    Changes in the levels of [ 14 C]indole-3-acetic acid (IAA) and [ 14 C]indoleacetylaspartic acid (IAAsp) were examined during adventitious root formation in mung bean (Vigna radiata [L.] R. Wilcz. Berken) stem cuttings. IAAsp was identified by GC-MS as the primary conjugate in IAA-treated cuttings. During root formation in IAA-treated cuttings, the level of [ 14 C]IAAsp increased rapidly the first day and then declined; [ 14 C]IAA was rapidly metabolized and not detected after 12 hours

  8. Effect of endomycorrhizae on the bioavailability of bound 14C residues to onion plants from an organic soil treated with [14C]fonofos

    International Nuclear Information System (INIS)

    Nelson, S.D.; Khan, S.U.

    1990-01-01

    Uptake of bound 14 C residues from an organic soil treated with radiolabeled fonofos (O-ethyl S-phenyl ethylphosphonodithioate) by selected Glomus endomycorrhiza and onion roots was studied. The hyphae of endomycorrhizal associations were capable of removing 14 C residues from the soil and transporting them to onion plants. Bioavailability of soil-bound 14 C residues, as measured by 14 C residue content in onion, was increased 32 and 40% over that of nonmycorrhizal plants by hyphae of Glomus intraradices and Glomus vesiculiferium, respectively. The data suggest that under field conditions endomycorrhizal infection may greatly increase the bioavailability of soil-bound pesticide residues to plants

  9. Comparative in vitro metabolism of 1-14C-oleic acid and 1-14C-erucic acid in liver, heart and skeletal muscles of rats

    International Nuclear Information System (INIS)

    Bhatia, I.S.; Sharma, A.K.; Ahuja, S.P.

    1978-01-01

    In vitro oxidation of 14 C-oleic and 1- 14 C-erucic acid and their incorporation into lipids by liver, heart and skeletal muscles from female albino rats were studied. These tissues were obtained from rats maintained for 120 days on low fat diet or diets containing 15% mustard oil or 15% groundnut oil. In all these tissues from rats on different types of diets, the oxidation of 1- 14 C-erucic acid was lower than that 1- 14 C-oleic acid. There was little accumulation of lipids in heart after 120 days of feeding mustard oil. Oxidation of 1- 14 C-erucic acid was enhanced in liver, heart and skeletal muscles of rats conditioned to the mustard oil diet supplying erucic acid. Oxidation of erucic acid was maximum in liver and least in heart, whereas there were no differences in the oxidation of 1- 14 C-oleic acid in these tissues. Incorporation of 1- 14 C-oleic acid into triglycerides and phospholipids was not affected by the type of diet or tissues Incorporation of 1- 14 C-erucic acid was mainly into triglycerides of heart and skeletal muscles of rats not accustomed to mustard oil diet whereas these tissues from rats accustomed to mustard oil diets incorporated 1- 14 C-erucic acid both into the triglycerides and phospholipids. (author)

  10. The fate of ingested [sup 14]C-urea in the urea breath test for Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Munster, D J; Chapman, B A; Burt, M J; Dobbs, B R; Allardyce, R A; Bagshaw, P F; Troughton, W D; Cook, H B [Christchurch Hospital (New Zealand)

    1993-08-01

    The metabolic fate of the radioactive carbon in the [sup 14]C-urea breath test for Helicobacter pylori was investigated in 18 subjects. After ingestion of labelled urea, breath was sampled for 24 h, and urine was collected for 3 days. Subjects were designated high or low expirers on the basis of their breath counts, and this agreed well with H. pylori serologic analyses. When given 185 or 37 kBq of [sup 14]C-urea, 51% of the label was recovered from the breath of high expirers, and 7% from the breath of low expirers. The mean combined urinary and breath recovery for high expirers was 86%, and for low expirers it was 97%. It is concluded that the long-term retention of [sup 14]C from ingested [sup 14]C-urea is low. The results enable a more accurate estimation to be made of radiation exposure resulting from the [sup 14]C-urea breath test. 16 refs., 3 figs., 2 tabs.

  11. The effect of light and ancymidol on the metabolism of 14C-ent-Kaurene in photoblastic lettuce (Lactuca sativa L. var. Grand Rapids) seeds

    International Nuclear Information System (INIS)

    Hazebroek, J.P.; Coolbaugh, R.C.

    1990-01-01

    The effect of light ancymidol on the metabolism of 14 C-kaurene in light-requiring lettuce seeds was investigated. Seeds were soaked in a solution of 14 C-kaurene in CH 2 Cl 2 with 0.1% Tween-20 for 24 h. The treatment did not reduce viability nor alter the light requirement. The solvent was removed and the seeds were incubated at 25 degree C in continuous light or dark in 20% (w/v) PEG or 10 mM anycymidol. Labeled metabolites were extracted and analyzed by reverse phase HPLC. 14 C-Kaurenol and 14 C-kaurenal were identified in seed incubated in 20% PeG in the light, while no acid EtOAc-soluble metabolites were found in seeds incubated in the dark. In the presence of ancymidol, 14 C-karuenol, 14 C-kaurenal, and a polar metabolite were found in seeds exposed to light, while only a trace of 14 C-kaurenol was detected in seeds incubated in the dark. These results indicate that the oxidation of kaurene is a light sensitive step in the biosynthesis of gibberellins in photoblastic lettuce seeds. Under these conditions ancymidol inhibits germination at a site different than the light sensitive kaurene oxidation step

  12. Stability of the 14 C-Radiolabelled insecticide guthion

    International Nuclear Information System (INIS)

    Fakhr, I.M.I.; Shaheen, F.A.; Hazzaa, N.I.; Hamdy, N.A.

    1993-01-01

    Under variable conditions simulating those of the agricultural practice, the effects of temperature and PH variations on the stability of 14 C-guthion have been studied. It was found that the insecticide is fairly stable in the acid medium and the half-life of the compound reached 230 days at 25 degree C and declined to about 7 days at 54 degree C, but in the alkaline medium, the degradation rate clearly increased as the PH increased and the half-life reached 24 hours in PH 11 at 25 degree C. In the neutral medium, the half-life was about eight days at 25 degree C while at 54 degree C, it was three days. The insecticide decomposed rapidly as the temperature was raised and the rate was much increased by the combined increase in heat and alkalinity. Some of the degradation products were identified as: O,O-dimethylthio- and di thiophosphoric acid, 4-O x O-3,4-dihydro, 1,2,3-benzo triazine and its hydroxymethyl derivative. 2 figs., 1 tab

  13. Adsorption and desorption of 14C-chlorsulfuron in soils

    International Nuclear Information System (INIS)

    Chen Zuyi; Cheng Wei; Mi Chunyun

    1995-01-01

    The adsorption and desorption of the 4 concentrations of 14 C-chlorsulfuron in 10 soils were studied. As a result the soils had weak adsorptions of chlorsulfuron and the adsorptions varied with different type of soils tested. Adsorption rate of paddy soil (infant red earth) from Hunan and latosol red earth from Hainan was 3%∼4%; Yellow-brown earth from Nanjing and red earth from Jiangxi was 6%∼9%; black soil from Jilin, paddy soil (infant red earth) from Jiangxi and red earth from Anhui was 10%∼14%; Albic bleached soil from Jilin and yellow fluvo-aquatic soil from Jiangsu was 19%∼23%. pH value had an influence on the adsorption and organic matter had not obvious influence on the adsorption. Chlorsulfuron absorbed in soil could be desorbed through water. The relation between the adsorption and desorption was negative. The weak adsorption in soil shows that chlorsulfuron is active movable and diffusible and likely to pollute the ecological environment

  14. Biodegradation of14 C-lindane by some soil fungi

    International Nuclear Information System (INIS)

    Attaby, H.S.H.; Adam, Y.M.

    1991-01-01

    In a culture medium incorporated with 14 C-labelled lindane, the 3 soil fungi helminthosporium sp., alternaria brassicola, and verticillium agaricinum were incubated for 10 days. Most of the recovered radioactivity was found to be maintained mainly in the medium of helminthosporium and alternaria but in case of verticillium the majority was associated with the mat. The 3 fungal species showed degradation capacity of 6.1, 5.1 and 3.2% of the total recovered radioactivity radioactivity as hydrolytic products. TLC chromatographic analysis of chloroform fractions revealed the presence of only unchanged lindane either in medium of mat. The aqueous fractions of the 3 fungal species, demonstrated three degraded products (unknown ι,π and tri) having Rf values of 0.40 - 0.47, 0.66 - 0.73, and 0.87 in addition to a polar compound (Rf = 0.07) with the major radioactivity. A certain percentage of radiocarbon 6.7, 5.7 and 30.3% of the mats of helminthosporium, alternria and verticillium, respectively.2 tab

  15. {sup 14}C determination in different bio-based products

    Energy Technology Data Exchange (ETDEWEB)

    Santos Arévalo, Francisco-Javier, E-mail: fj.santos@csic.es [Centro Nacional de Aceleradores (Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía), Thomas Alva Edison 7, 41092 Seville (Spain); Gómez Martínez, Isabel; Agulló García, Lidia; Reina Maldonado, María-Teresa [Centro Nacional de Aceleradores (Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía), Thomas Alva Edison 7, 41092 Seville (Spain); García León, Manuel [Centro Nacional de Aceleradores (Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía), Thomas Alva Edison 7, 41092 Seville (Spain); Dpto. de Física Atómica Molecular y Nuclear, Universidad de Sevilla, Reina Mercedes s/n, 41012 Seville (Spain)

    2015-10-15

    Radiocarbon determination can be used as a tool to investigate the presence of biological elements in different bio-based products, such as biodiesel blends. These products may also be produced from fossil materials obtaining the same final molecules, so that composition is chemically indistinguishable. The amount of radiocarbon in these products can reveal how much of these biological elements have been used, usually mixed with petrol derived components, free of {sup 14}C. Some of these products are liquid and thus the handling at the laboratory is not as straightforward as with solid samples. At Centro Nacional de Aceleradores (CNA) we have tested the viability of these samples using a graphitization system coupled to an elemental analyzer used for combustion of the samples, thus avoiding any vacuum process. Samples do not follow any chemical pre-treatment procedure and are directly graphitized. Specific equipment for liquid samples related to the elemental analyzer was tested. Measurement of samples was performed by low-energy AMS at the 1 MV HVEE facility at CNA, paying special attention to background limits and reproducibility during sample preparation.

  16. Depletion of [14C]clorsulon in cows' milk

    International Nuclear Information System (INIS)

    Chiu, S.H.L.; Baylis, F.P.; Taub, R.; Green, M.; Halley, B.A.; Bodden, R.M.

    1989-01-01

    Radioactive residue levels were determined in milk and plasma of Holstein cows dosed once with an oral suspension of 14 C-labeled clorsulon at 7 mg/kg of body weight. Average milk residue levels decreased from 0.54 ppm at 0.9 day postdose to 0.004 ppm at 6.9 days postdose with a half-life of 0.81 day. The drug residue was isolated by a batch adsorption method on an affinity agarose gel of carbonic anhydrase-Sepharose 4B and analyzed by HPCL-reverse isotope dilution assay (RIDA). This novel method greatly simplified the extraction of drug residue from milk and provided pure drug residue isolates. RIDA results of the isolates indicated that the unchanged drug was the major residue component in milk at 0-4 days postdose accounting for 56-99% of the total radioactive residue. Depletion half-life of the parent drug was 0.82 day, in close agreement with that of the total residue in milk. About 0.7% of the dose was recovered in the milk during the 6.9-day period

  17. Metabolism of 14C-diazinon by gypsy moth larvae

    International Nuclear Information System (INIS)

    Ahmad, S.; Forgashi, A.J.

    1975-01-01

    The metabolic fate of diazinon in larvae of Porthetria dispar (L.) was determined using 14 C-ring-labeled material. Following a 4-h ingestion period, 28.7 percent of the total recovered activity was present as diazinon in the larvae and 0.2 percent in the feces at 1 hr; by 12 h these amounts had changed to 1.4 and 15.4 percent, respectively. The major transformation products were 2,isopropyl-4-methyl-6-pyrimidinol greater than diazoxon greater than hydroxydiazinon greater than 2-(2'-hydroxy-2'-propyl)-4-methyl-6-pyrimidinol. Small amounts of 5 additional products were detected but were not identified. Metabolism of topically applied diazinon was the same qualitatively as that of ingested diazinon, based on a comparison of chloroform-extractable metabolites, although quantitative differences were evident. The synergists 2,6-dichlorobenzyl-2-propynyl ether (GA4-282) and piperonyl butoxide (PB) altered the metabolism of diazinon (both ingested and topical doses) by apparently similar actions, resulting in a reduction in the formation of 2-isopropyl-4-methyl-6-pyrimidinol, hydroxydiazinon, and 2-(2'-hydroxy-2'-propyl)-4-methyl-6-pyrimidinol

  18. Biosynthesis of gallic and ellagic acids with 14C-labeled compounds in Acer and Rhus leaves

    International Nuclear Information System (INIS)

    Ishikura, Nariyuki; Hayashida, Shunzo; Tazaki, Kiyoshi

    1984-01-01

    The biosynthetic pathway for gallic and ellagic acids in young, mature and autumn leaves of Acer buergerianum and Rhus succedanea was examined by tracer experiments, and also by isotope competition, with D-shikimic acid- 14 C, L-phenylalanine-U- 14 C, L-phenyllactic acid-U- 14 C, gallic acid-G- 14 C and their unlabeled compounds. In young leaves of both plants, the incorporation rate of labeled shikimic acid into gallic acid was significantly higher than that of labeled phenylalanine, whereas in the mature and autumn leaves the latter was a good precursor rather than the former for the gallic acid biosynthesis. Therefore, two pathways for gallic acid formation, through β-oxidation of phenylpropanoid and through dehydrogenation of shikimic acid, could be operating in Acer and Rhus leaves, and the preferential pathway is altered by leaf age. In both plants, the incorporation rate of labeled phenyllactic acid during a 24 hr metabolic period was almost the same as that of labeled phenylalanine. The incorporation of D-shikimic acid-G- 14 C, L-phenylalanine-U- 14 C and L-phenyllactic acid-U- 14 C into ellagic acid was very similar to the case of the radioactive gallic acid formation. Furthermore, regardless of the presence of unlabeled shikimic acid and/or phenylalanine, incorporation of the radioactivity of labeled gallic acid into ellagic acid occurred at a very high rate, suggesting the reciprocal radical reaction of gallic acid for the ellagic acid formation. The incorporation of labeled compounds into ellagitannins was also examined and their biosynthesis discussed further. (author)

  19. Accumulation of Sellafield-derived radiocarbon ((14)C) in Irish Sea and West of Scotland intertidal shells and sediments.

    Science.gov (United States)

    Tierney, Kieran M; Muir, Graham K P; Cook, Gordon T; MacKinnon, Gillian; Howe, John A; Heymans, Johanna J; Xu, Sheng

    2016-01-01

    The nuclear energy industry produces radioactive waste at various stages of the fuel cycle. In the United Kingdom, spent fuel is reprocessed at the Sellafield facility in Cumbria on the North West coast of England. Waste generated at the site comprises a wide range of radionuclides including radiocarbon ((14)C) which is disposed of in various forms including highly soluble inorganic carbon within the low level liquid radioactive effluent, via pipelines into the Irish Sea. This (14)C is rapidly incorporated into the dissolved inorganic carbon (DIC) reservoir and marine calcifying organisms, e.g. molluscs, readily utilise DIC for shell formation. This study investigated a number of sites located in Irish Sea and West of Scotland intertidal zones. Results indicate (14)C enrichment above ambient background levels in shell material at least as far as Port Appin, 265 km north of Sellafield. Of the commonly found species (blue mussel (Mytilus edulis), common cockle (Cerastoderma edule) and common periwinkle (Littorina littorea)), mussels were found to be the most highly enriched in (14)C due to the surface environment they inhabit and their feeding behaviour. Whole mussel shell activities appear to have been decreasing in response to reduced discharge activities since the early 2000s but in contrast, there is evidence of continuing enrichment of the carbonate sediment component due to in-situ shell erosion, as well as indications of particle transport of fine (14)C-enriched material close to Sellafield. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. High-Sensitivity GaN Microchemical Sensors

    Science.gov (United States)

    Son, Kyung-ah; Yang, Baohua; Liao, Anna; Moon, Jeongsun; Prokopuk, Nicholas

    2009-01-01

    Systematic studies have been performed on the sensitivity of GaN HEMT (high electron mobility transistor) sensors using various gate electrode designs and operational parameters. The results here show that a higher sensitivity can be achieved with a larger W/L ratio (W = gate width, L = gate length) at a given D (D = source-drain distance), and multi-finger gate electrodes offer a higher sensitivity than a one-finger gate electrode. In terms of operating conditions, sensor sensitivity is strongly dependent on transconductance of the sensor. The highest sensitivity can be achieved at the gate voltage where the slope of the transconductance curve is the largest. This work provides critical information about how the gate electrode of a GaN HEMT, which has been identified as the most sensitive among GaN microsensors, needs to be designed, and what operation parameters should be used for high sensitivity detection.

  1. Defective [U-14 C] palmitic acid oxidation in Duchenne muscular dystrophy

    International Nuclear Information System (INIS)

    Carroll, J.E.; Norris, B.J.; Brooke, M.H.

    1985-01-01

    Compared with normal skeletal muscle, muscle from patients with Duchenne dystrophy had decreased [U-14 C] palmitic acid oxidation. [1-14 C] palmitic acid oxidation was normal. These results may indicate a defect in intramitochondrial fatty acid oxidation

  2. Defective (U-14 C) palmitic acid oxidation in Duchenne muscular dystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, J.E.; Norris, B.J.; Brooke, M.H.

    1985-01-01

    Compared with normal skeletal muscle, muscle from patients with Duchenne dystrophy had decreased (U-14 C) palmitic acid oxidation. (1-14 C) palmitic acid oxidation was normal. These results may indicate a defect in intramitochondrial fatty acid oxidation.

  3. Urvina Bay, Galapagos Coral Radiocarbon (delta 14C) Data for 1956 to 1982

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Urvina Bay coral radiocarbon (14C) timeseries. (90 deg W, 0.5 deg S) Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4 per...

  4. Synthesis of uniformly labelled organic compounds by polymerization of 14C ethylene

    International Nuclear Information System (INIS)

    Dauphin, J.-F.

    1972-01-01

    The synthesis of 14 C uniformly labelled compounds is described. By polymerization of 14 C ethylene, linear olefins with a double bond at α position were obtained. From these olefins, uniformly labelled alkanes, alcohols and acids were prepared [fr

  5. Development of a highly sensitive lithium fluoride thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Moraes da Silva, Teresinha de; Campos, Leticia Lucente

    1995-01-01

    In recent times, LiF: Mg, Cu, P thermoluminescent phosphor has been increasingly in use for radiation monitoring due its high sensitivity and ease of preparation. The Dosimetric Materials Production Laboratory of IPEN, (Nuclear Energy Institute) has developed a simple method to obtain high sensitivity LiF. The preparation method is described. (author). 4 refs., 1 fig., 1 tab

  6. 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)...

  7. Triggers for a high sensitivity charm experiment

    International Nuclear Information System (INIS)

    Christian, D.C.

    1994-07-01

    Any future charm experiment clearly should implement an E T trigger and a μ trigger. In order to reach the 10 8 reconstructed charm level for hadronic final states, a high quality vertex trigger will almost certainly also be necessary. The best hope for the development of an offline quality vertex trigger lies in further development of the ideas of data-driven processing pioneered by the Nevis/U. Mass. group

  8. Disposition of [14C]γ-cyclodextrin in germ-free and conventional rats

    NARCIS (Netherlands)

    Bie, A.T.H.J. de; Ommen, B. van; Bär, A.

    1998-01-01

    The absorption, disposition, metabolism, and excretion of 14C-labeled γ-cyclodextrin ([14C]γ-CD) was examined in four separate experiments with Wistar rats. In experiment 1, [14C]γ-CD (25 μCi, 600 mg/kg body wt) was administered intravenously to four male and four female conventional rats. In

  9. Radioactive intermediate products in the photolysis of the system [1-14C] tributyltin oxide cellulose

    International Nuclear Information System (INIS)

    Kloetzer, D.

    1982-01-01

    Interactions between matrix and applied biocide in the photochemical degradation of the system [1- 14 C] tributyltin oxide/cellulose have been investigated. The intermediate formation of [1- 14 C] tributylstannyl cellulose ethers was found to be the most important step. The photochemical preparation of bis [8- 14 C] tributylstannyl glucose ether is described. (author)

  10. Disposition of 14C-α-cyclodextrin in germ-free and conventional rats

    NARCIS (Netherlands)

    Ommen, B. van; Bie, A.T.H.J. de; Bär, A.

    2004-01-01

    The absorption, disposition, metabolism, and excretion of uniformly 14C-labeled α-cyclodextrin (14C-α-CD) was examined in four separate experiments with Wistar rats. In Experiment 1, 14C-α-CD (25μCi, 50mg/kg bw) was administered intravenously to four male and four female conventional rats. In

  11. An enzymic method for the determination of [1-14C] lactose

    International Nuclear Information System (INIS)

    Davies, E.; Bourke, E.; Costello, J.

    1975-01-01

    A simple, rapid and specific method for the determination of [1- 14 C] lactose in biological fluids is described. It is based on the enzymic removal of the 1- 14 C atom of lactose as [ 14 C] carbon dioxide, using commercially available enzymes. The assay involves only one critical addition and the entire reaction can be carried out in a scintillation vial. (author)

  12. Synthesis of two 14C-labeled catechol-o-methyltransferase inhibitors

    International Nuclear Information System (INIS)

    Karlsson, Carita; Honkanen, Erkki

    1991-01-01

    14 C-labelled 3-(3,4-dihydroxy-5-nitrophenylmethylidene)-2,4-pentanedione and 14 C-labelled E-N,N-diethyl-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide have been synthesized from [carbonyl- 14 C]vanillin. (author)

  13. Radiochemically pure [1-14C]valproic acid--a mixture of labeled structural isomers

    International Nuclear Information System (INIS)

    Dickinson, R.G.; Wood, B.T.; Kluck, R.M.; Hooper, W.D.

    1986-01-01

    Ongoing studies of the disposition of valproic acid (VPA) and its glucuronide conjugate required the radiolabeled drug for greater sensitivity and tracing of oxidation metabolites. [1- 14 C]VPA hereinafter called LABEL (radiochemical purity greater than 98% as determined by paper and thin layer chromatography) was purchased from Amersham International, U.K. Quantitative analysis of VPA and VPA-glucuronide in bile and urine samples from rats given VPA and tracer LABEL by our standard gas chromatographic assay showed gross discrepancies with the results obtained by liquid scintillation counting of the same extracts. Examination of the purity of LABEL was therefore undertaken. Equilibration of LABEL between various organic-aqueous solvent pairs was identical to that of authentic VPA. However, gas chromatographic-mass spectrometric analysis of the trimethylsilyl derivative of LABEL revealed it to be a mixture of labeled 2-methylheptanoic acid (approximately 60%), 2-ethylhexanoic acid (approximately 30%), and 2-propylpentanoic acid (i.e., VPA, 5-10%). The origin of the isomers of VPA in LABEL was logically traced to the synthetic procedure--coupling of the Grignard reagent of (an isomeric mixture of 2-, 3-, and 4-) chloroheptane(s) with [ 14 C]carbon dioxide. This result highlights the inadequacy of the quality control procedures used and reinforces the necessity for caution in accepting the quoted purity of radiolabeled drugs

  14. 14C ages of Omuroyama volcano, Izu Peninsula

    International Nuclear Information System (INIS)

    Saito, Toshihito; Takahashi, Shuichi; Wada, Hideki

    2003-01-01

    A partly carbonized wood trunk was discovered below the Omuroyama tephra covered by a lava, and it was dated to be 3,700±100 y. B.P., by the benzene liquid scintillation method for radiocarbon age determination. We have investigated the circumstance of the discovery of the wood sample based on an interview of the person who collected the sample during his operation of building construction. According to him, the wood specimen was found at 1.5-2 m depth beneath the ground level when the operator removed the massive blackish lava block. This specimen was laid down covered by black sandy pebbles. The size of the wood trunk was 105 cm long and 45 cm and 35 cm along wide and short diameter, respectively. We also revealed the burial environment of the wood to be related with the Omuroyama tephras and lava flow, based on our volcanostratigraphic observation of the surrounding area. The tephras covering the trunk were identified as the Omuroyama tephra B, C, and D, which were defined by Koyano et al. (1996) around this area, and these tephras were covered by the Omuroyama lava flow II (Koyano et al., 1996). The wood trunk was mostly fresh and only its branch was burned. It can be estimated that the trunk has been preserved surrounded by ground water, since several tons of ground water gushed out when the aquifer was opened for construction. On this context, this trunk was buried at the early stage of the volcanism of Omuroyama volcano covered by the tephras, and later also covered by the Omuroyama lava II. We can not conclude that the burned branch is ascribed to direct burning by the Omuroyama lava flow II but this 14 C dating resultant is also concordant all archaeological evidences reported. (author)

  15. Studies on 129I and 14C in environmental samples by AMS

    International Nuclear Information System (INIS)

    Muramatsu, Yasuyuki

    2010-01-01

    We have carried out studies on 129 I and 14 C in environmental samples by AMS (accelerator mass spectrometry). In this paper summary of our results are described. Iodine is an essential element for humans and it pays an important role in thyroid gland. There are more than 30 isotopes of iodine. Among radioiodines 129 I has the longest half-life (1.57x10 7 y). This nuclide is released into the environment from nuclear weapons test, accidents of nuclear facilities (e.g. Chernobyl accident) and operation of spent fuel reprocessing plants. Since soil accumulates iodine, we have focused on the levels of both 129 I and 127 I in surface soils. In our previous studies, we used NAA (neutron activation analysis) for the determination. However, due to the limitation of its analytical sensitivity we could not detect 129 I in samples from background areas. In this study we have analyzed 129 I/ 127 I ratios by AMS and 127 I concentrations by ICP-MS (inductively coupled plasma spectrometry) after separation of iodine from soil by pyrohydrolysis and solvent extraction techniques. Using these methods, we have analyzed samples collected from different areas in Japan. Analytical results for surface soils collected from background areas were in the ranges 1.4 x 10 -5 - 4.6 x 10 -3 Bq/Kg as 129 I concentrations and 3.9 x 10 -11 - 3.0 x 10 -8 as 129 I/ 127 I ratios. The 129 I levels in Tokaimura, where a spent fuel reprocessing plant is located, were one to three orders of magnitude higher than those in background samples. The levels were higher in forest soils than those in field and rice paddy soils due to the interception effect of atmospheric 129 I by tree canopies. A wide range of stable iodine concentrations (0.4-143ppm) was observed. Rice paddy soils contained significantly lower iodine than forest and upland field soils. This should be explained by the desorption of iodine from the rice paddies due to microbial activities during the cultivation. Vertical distributions of 129 I

  16. Degradation and residues of trifluralin and metalaxyl in soils treated with 14C-trifluralin and 14C-metalaxyl, under laboratory conditions

    International Nuclear Information System (INIS)

    Musumeci, M.R.; Ruegg, E.F.

    1986-01-01

    The behavior of the herbicide 14 C-trifluralin and the fungicide 14 C-metalaxyl was studied under laboratory conditions in Red Latosol and Yellow Red Podzol soils in samples Kept flooded, sterilized and with humidity equivalent to 60% of the water field capacity. The degradation of both pesticides is discussed. (M.A.C.) [pt

  17. Metabolism of 4-/sup 14/C-dehydroepiandrosterone and 4-/sup 14/C-4-Androstene-3, 17-dione by isolated cells of early human placenta

    Energy Technology Data Exchange (ETDEWEB)

    Dziadkowiec, I; Czarnik, Z; Rembiesa, R [Department of Endocrinology, Institute of Pharmacology, Polish Academy of Sciences, Krakow

    1977-03-01

    The preparation of isolated cells was used for the study of the metabolism of 4-/sup 14/C-dehydroepiandrosterone and 4-/sup 14/C-4-androstene-3,17-dione in early human placenta. Free cell suspension converted dehydroepiandrosterone and 4-androstene-3,17-dione into estrone, estradiol-17..beta.., 4-androstene-3,17-dione and testosterone.

  18. {sup 14} C dating by using mass spectrometry with particle accelerator; Datacao por {sup 14} C utilizando espectrometria de massa com acelerador de particulas

    Energy Technology Data Exchange (ETDEWEB)

    Santos, G.M.; Gomes, P.R.S. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Fisica]. E-mail: paulogom@if.uff.br; Yokoyama, Y. [Australian National Univ., Canberra (Australia). Research School of Earth Science; Tada, M.L. di; Cresswell, R.G.; Fifield, L.K. [Australian National Univ., Canberra (Australia). Dept. of Nuclear Physics

    1999-03-01

    The different aspects concerning the {sup 14} C dating are described, including the cosmogenic origin of {sup 14} C, its production and absorption by matter, the procedures to be followed for the age determination and the associated errors, particularly by the Accelerator Mass Spectrometry (AMS) technique, and the different steps of the sample preparation process. (author)

  19. Bioconcentration of 14 C-Carbofuran and 14 C- Lindane in fresh water Tilapia Nilitica and the bioavailability of their residues to rats

    International Nuclear Information System (INIS)

    Aly, M.A.S.; Afifi, L.M.

    1997-01-01

    Tilapia Nilotica were exposed to 14 C- carbofuran (125 MUg/1) and 14 C - lindane (80 MUg/1) for 96 h. Uptake period followed by 8 days depuration period. The bioconcentration factor (BCF) for carbofuran reached 32.4 at 12 h and 82 for lindane at 48 h. The amount of 14 C-activity found in fish treated with 14 C - carbofuran after the uptake period showed the following descending order: viscera > remaining parts > gills > muscles. In case of 14 C - lindane treated fish the recovered amount followed the order; remaining parts> viscera > gills muscles. During the depuration period, carbofuran residues taken up by fish were eliminated in 2 phases, an initial rapid phase followed by a slower gradual one. However, the rate of elimination in case of lindane was much slower especially during the first 2 days. At the end of the depuration period (8 days), the muscles (edible portion) contained 10% and 58% of 14 C -activity in case of carbofuran and lindane treated groups, respectively. Both insecticides proved to be bioavailable when rats were fed treated fish. Of the administered dose, 44.1% and 53.0% were excreted in urine and feces case of 14 C-carbofuran while in case of 14 C - lindane it was 30.9% and 41.7% for urine and feces, respectively. 2 figs., 2 tabs

  20. Early incorporation and distribution of 14C-photosynthates after 14C-feeding for a brief period in tea plant

    International Nuclear Information System (INIS)

    Hakamata, Katsuhiro

    1981-01-01

    In order to clarify the early incorporation and distribution of 14 C-photosynthetic products in tea plants after 14 C-feeding for a brief period, 14 C-tracer experiments were performed, using the winter leaves, first crop shoots and young tea plants of a cultivar, Yabukita. As the results of the experiment on leaf disks by 14 C-Feeding for one minute, the 14 C-activity in the ethanol soluble fraction distributed in the anionic, cationic and neutral fractions in this order. When the time of feeding was extended to 10 min, the distribution in the cationic fraction decreased, and that in the neutral fraction increased. In the experiment on shoots, after the end of 10 min assimulation, the 14 C-activity in the ethanol soluble fraction distributed in the neutral, cationic and anionic fractions in this order. In course of time, the distribution in the cationic and anionic fractions decreased, and that in the neutral fraction increased. As the results of 14 C-feeding to young tea plants for 2.5 hours, 70 - 95% of the 14 C-activity in the ethanol soluble fraction distributed in the neutral fraction. Sucrose seemed to be the primary and early product of photosynthesis, and might be the principal carbohydrate form of translocation and reserve in tea plants. Raffinose and stachyose played almost the same role as sucrose. (Kako, I.)

  1. Effects of muffin processing on fumonisins from 14C-labeled toxins produced in cultured corn kernels.

    Science.gov (United States)

    Avantaggiato, Giuseppina; De La Campa, Regina; Miller, J David; Visconti, Angelo

    2003-10-01

    The persistence of fumonisins during cooking is known to be affected by several factors, including thermal degradation and the presence of various ingredients in corn-based food recipes that can react with the toxin. A method for the production of corn kernels containing 14C-fumonisins was developed. The corn kernels were colonized by Fusarium verticillioides MRC 826 and supplemented with 1,2-14C-sodium acetate. The specific activity of 14C-FB1 produced made the study of its fate in cornmeal muffins possible. The double-extraction acetonitrile-water-methanol/immunoaffinity column/o-phthaldialdehyde high-performance liquid chromatography (HPLC) method was used to determine FB1 levels in cornmeal muffins. Reductions in FB1 levels in muffins spiked with 14C-labeled and unlabeled FB1 (43 and 48%, respectively) were similar, indicating that the extraction method was efficient and consistent with previous reports. However, with the labeled corn kernel material, recovery levels based on the 14C counts for the eluate from an immunoaffinity column were much higher (90%). This finding indicates that some fumonisin-related compounds other than FB1 that were present in the cornmeal were recognized by the antibodies but not by the HPLC method.

  2. Influence of a few composts on the mineralization of 14C phenmedipham in a fresh meadow soil and the immobilization of the 14C residues

    International Nuclear Information System (INIS)

    Bellinck, C.; Mayaudon, J.

    1983-01-01

    The influence of four composts on the mineralization of 14 C phenmedipham in a fresh soil and the distribution of 14 C phenmedipham and its 14 C residues after one year incubation were studied. Straw compost had an important positive effect on the degradation of the herbicide. After a negative influence during the 15 first days of incubation, composts of mushroombeds, grapes and oak-bark - hen-dung had little influence. The soils treated with these three last composts showed a more important complexation of 14 C than the control-soil or the soil treated with straw-compost. Calculation of the quantity of free 14 C substances in the soil after one year incubation gave for the four composts values comprised between 39 and 84% of that of the control [fr

  3. Effect of a few amendments on the mineralization of 14C phenmedipham in a fresh meadow soil and the immobilization of the 14C residues

    International Nuclear Information System (INIS)

    Bellinck, C.

    1983-01-01

    The influence of a few amendments on the mineralization of 14 C phenmedipham in a fresh soil and the distribution of 14 C phenmedipham and its 14 C residues after one year incubation were studied. The N and NPK fertilizers, glucose, cellulose and amorphous calcic humates had a positive effect on the mineralization of the herbicide. Straw, NAFS extract and amorphous lignin had little influence while colloidal lignin and colloidal calcic humates had a negative effect on the mineralization. All the amendments tested increased the quantity of 14 C substances fixed on the soil constituents and so decreased pollution. Calculation of the quantity of free 14 C in the soil after one year incubation showed for the various amendments values comprised between 56 and 93% of that of the control [fr

  4. The sup 14 C-urea breath-test for the detection of gastric Campylobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Surveyor, I; Goodwin, C S; Mullan, B P; Geelhoed, E; Warren, J R; Murray, R N; Waters, T E; Sanderson, C R [Royal Perth Hospital (Australia)

    1989-10-16

    Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of {sup 14}C -urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of {sup 14}C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with Campylobacter (C.) pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of {sup 14}C-urea in 24 patients with negative microbiological results was 6.9{plus minus}4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastricbiopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P=0.0001) with the serological antibody test-result. The role of non-invasive tests - enzyme-linked immunosorbent assays and {sup 14}C-urea breath-testing - in the management of gastritis and peptic ulcer disease is discussed. We consider that the {sup 14}C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment. 38 refs., 2 figs., 1 tab.

  5. The Relationship Between 14C Urea Breath Test Results and Neutrophil/Lymphocyte and Platelet/Lymphocyte Ratios

    Directory of Open Access Journals (Sweden)

    Ertan Şahin

    2018-04-01

    Full Text Available Aim: Neutrophil/lymphocyte ratio (NLR and platelet/lymphocyte ratio (PLR are used as inflammatory markers in several diseases. However, there are little data regarding the diagnostic ability of NLR and PLR in Helicobacter pylori. We aimed to assess the association between the 14C urea breath test (14C-UBT results and NLR and PLR in H. pylori diagnosis. Methods: Results of 89 patients were retrospectively analysed in this study. According to the 14C-UBT results, patients were divided into two groups: H. pylori (+ and H. pylori (- (control group. Haematological parameters, including hemoglobine, white blood cell (WBC count, neutrophil count, lymphocyte count, NLR, platelet count, and PLR were compared between the two groups. Results: The mean total WBC count, neutrophil count, NLR and PLR in H. pylori (+ patients were significantly higher than in the control group (p<0.001 for all these parameters. In the receiver operating characteristic curve analysis, the cut-off value for NLR and PLR for the presence of H. pylori was calculated as ≥2.39 [sensitivity: 67.3%, specificity: 79.4%, area under the curve (AUC: 0.747 (0.637-0.856, p<0.0001] and ≥133.3 [sensitivity: 61.8%, specificity: 55.9%, AUC: 0.572 (0.447-0.697, p<0.05], respectively. Conclusion: The present study shows that NLR and PLR are associated with H. pylori positivity based on 14C-UBT, and they can be used as an additional biomarker for supporting the 14C-UBT results.

  6. Estimation of radiation dosage and transmutation effect of 14C involved in measuring rate of albumin synthesis with 14C-carbonate

    International Nuclear Information System (INIS)

    Yap, A.H.; Hafkenscheid, J.C.M.; Goossens, C.M.I.C.; Buys, W.C.A.M.; Binkhorst, R.A.; Van Tongeren, J.H.M.

    1975-01-01

    For direct measurement of the rate of albumin synthesis, Na 2 14 CO 3 was used intravenously. The assessment of the radiation hazard involved in the study was based on the knowledge of the minimum dose of Na 2 14 CO 3 necessary for a sufficient incorporation of 14 C in the guanidine-C of arginine in albumin to obtain measurable radioactivity. By measurement of expired 14 CO 2 and excreted 14 C-urea in the urine during a 5-hr period following intravenous administration of Na 2 14 CO 3 in five subjects, some quantitative data on 14 C retention and radiation dosage were obtained. In comparison with animal studies, the rate of expiration of 14 CO 2 in man is slower. About 50 percent of the total radioactivity injected was lost through the respiratory route in the first hour. The total amount of expired 14 C during the 5 hr of investigation was about 75 percent of the injected dose for the five subjects. The amount of 14 C excreted as urinary 14 C-urea during the 5 hr of investigation is very small in comparison with the expired 14 C; it was only about 0.5 percent of the dose injected. The total absorbed radiation dose after complete elimination of 14 C from the body was calculated with various assumptions. The extra risk of genetic damage due to disintegration of retained 14 C in comparison with that of natural 14 C in the body during 30 living years is about 50 percent. (U.S.)

  7. Appraisal of the /sup 14/C-glycocholate acid test with special reference to the measurement of faecal /sup 14/C excretion

    Energy Technology Data Exchange (ETDEWEB)

    Scarpello, J H.B.; Sladen, G E [Royal Hospital, Sheffield (UK). Academic Div. of Medicine

    1977-09-01

    The /sup 14/C-glycocholate test, including the measurement of marker corrected faecal /sup 14/C, has been assessed in the following groups of subjects: normal controls (18), patients with diarrhoea not attributable to altered bile acid metabolism (21), patients with diverticula of the small intestine (12), patients with previous resection of ileum and often proximal colon (34), and established ileostomists (10). Patients with diverticular disease had increased breath /sup 14/CO/sub 2/ excretion, but normal faecal excretion of /sup 14/C, and this test was more frequently abnormal than the Schilling test. Ileostomists excreted increased amounts of faecal /sup 14/C, even when the ileum was intact and apparently normal. The pattern after resection was complex. Breath /sup 14/C output was normal if the ileal resection was less than 25 cm in length, although some of these patients had increased faecal /sup 14/C excretion if, in addition, at least 15 cm of proximal colon had been resected or by-passed. Longer ileal resections were associated with increased breath and/or faecal /sup 14/C excretion, depending in part on the length of colon resected or by-passed and the 24 hour faecal volume. Fewer than half these patients had both increased breath and faecal excretion of isotope and faecal /sup 14/C alone was occasionally normal with an ileal resection of 50 cm or more. The /sup 14/C-glycocholate test was more frequently abnormal than the Schilling test in this group. The use of faecal marker correction had only a minor impact on the results. These data suggest that, in patients with ileal resection, faecal /sup 14/C, like faecal weight, is determined by the extent of colonic resection as well as by the amount of ileum resected.

  8. Effect of oil refining processes on 14 C-tetrachlorvinphos residues in soya bean oil

    International Nuclear Information System (INIS)

    Farghaly, M.; Zayed, S.M.A.D.

    1986-01-01

    Crude soya bean oil extracted from grains treated with 14 C-tetrachlorvinphos and stored for 30 weeks was subjected to different refining processes. The effect of commercial refining processes, namely: alkali treatment, bleaching, winterization and deodorization on the nature and magnitude of the originally present residues was investigated. A high percentage (52%) of the residues was eliminated during alkali neutralization. No potentially toxic materials were detected among the identified degradation products. The obtained data showed that the ultimate degradation products were dimethyl phosphate and mono methyl phosphate.2 tab.,2 scheme

  9. Dietary reconstruction and reservoir correction of 14C dates on bones from pagan and early Christian graves in Iceland

    DEFF Research Database (Denmark)

    Sveinbjörnsdóttir, Árný E; Heinemeier, Jan; Arneborg, Jette

    2010-01-01

    between the excavation site and the seashore. We have radiocarbon dated 47 of these skeletons and used the carbon isotopic composition (?13C) to estimate and correct for the marine reservoir effect (the 14C difference between terrestrial and mixed marine organisms). The reservoir-corrected ages lie...... in the range of AD 780?1270 (68.2% probability). Reservoir age corrections were checked by comparing 14C dates of a horse (terrestrial diet), a dog (highly marine diet), and a human (mixed diet) from the same burial. The range in measured marine protein percentage in individual diet is from about 10% up to 55...... in AD 1211. Using our dietary reconstruction, his bones were about 17% marine, which is within the range of human skeletons from the same area, and the reservoir-corrected calibrated 14C age of the skeleton is in accord with the historical date....

  10. Low Power and High Sensitivity MOSFET-Based Pressure Sensor

    International Nuclear Information System (INIS)

    Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

    2012-01-01

    Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

  11. 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)

  12. Adsorption and leaching of novel fungicide pyraoxystrobin on soils by 14C tracing method.

    Science.gov (United States)

    Liu, Xunyue; Wu, Huiming; Hu, Tingting; Chen, Xia; Ding, Xingcheng

    2018-01-19

    Pyraoxystrobin, (E)-2-(2-((3-(4-chlorophenyl)-1-methyl-1H-pyrazole-5-yloxy)methyl)phenyl)-3-methoxyacrylate, is a newly developed strobilurin fungicide with high antifungal efficiency. It has high potential to enter soil environments that might subsequently impact surface and groundwater. Therefore, 14 C-labeled pyraoxystrobin was used as a tracer to study the adsorption/desorption and migration behavior of this compound under laboratory conditions in three typical agricultural soils. The adsorption isotherms conformed with the Freundlich equation. Single factor analysis showed that organic matter content was the most important factor influencing the adsorption. The highest adsorption level was measured in soil with low pH and high organic carbon content. Once adsorbed, only 2.54 to 6.41% of the adsorbed compound could be desorbed. In addition, the mobility results from thin-layer chromatography and column leaching studies showed that it might be safe to use pyraoxystrobin as a fungicide without causing groundwater pollution from both runoff and leaching, which might be attributed to its strong hydrophobicity. High organic matter content enhanced pyraoxystrobin adsorption and desorption because of the rule of similarity (lipid solubility). In the column leaching study, 95.02% (minimum value) of the applied 14 C remained within the upper 4.0-cm layer after 60 days.

  13. Do site-specific radiocarbon measurements reflect localized distributions of 14C in biota inhabiting a wetland with point contamination sources?

    Science.gov (United States)

    Yankovich, T; King-Sharp, K J; Benz, M L; Carr, J; Killey, R W D; Beresford, N A; Wood, M D

    2013-12-01

    Duke Swamp is a wetland ecosystem that receives (14)C via a groundwater pathway originating from a waste management area on Atomic Energy Canada Limited's Chalk River Laboratories site. This groundwater reaches the surface of the swamp, resulting in relatively high (14)C levels over an area of 146 m(2). The objective of this study was to quantify (14)C concentrations in flora and fauna inhabiting areas of Duke Swamp over the gradient of (14)C activity concentrations in moss to determine whether (14)C specific activities in receptor biota reflect the localized nature of the groundwater source in the swamp. Representative receptor plants and animals, and corresponding air and soil samples were collected at six sites in Duke Swamp with (14)C specific activities in air that ranged from 1140 to 45,900 Bq/kg C. In general, it was found that specific activities of (14)C in biota tissues reflected those measured in environmental media collected from the same sampling site. The findings demonstrate that mosses could be used in monitoring programs to ensure protection of biota in areas with elevated (14)C, negating the need to capture and euthanize higher organisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Atmospheric nuclear weapon test history as characterized by the deposition of 14C in human teeth

    International Nuclear Information System (INIS)

    Nishizawa, K.; Togari, A.; Matsumoto, S.; Nagatsu, T.

    1990-01-01

    The 14 C concentration in the collagen of human teeth was retrospectively investigated to determine whether its incorporation was related to atmospheric testing of nuclear weapons. Teeth were extracted for dental therapy from July 1987 to February 1988 from patients who were residents in Japan. Tooth collagen was extracted with HCl and converted to amorphous C by heating in a vacuum line. Specimens for 14 C analysis were prepared by mixing the amorphous C with silver powder. The 14 C concentration was measured by mass spectrometer. The 14 C concentration in tooth collagen rapidly increased in 1961 after the bomb tests, peaked around 1967-1968, and then gradually decreased. The collagen of human teeth maintains the 14 C concentration at the age of root completion for life. The results of this study indicate that the history of environmental contamination from atmospheric nuclear weapon's tests has been characterized by deposition of 14 C in the tooth collagen 14 C of human beings

  15. Studies on the distribution of 14C-labelled PCB in the body, 4

    International Nuclear Information System (INIS)

    Nagao, Soshichi; Hosoya, Hideo

    1976-01-01

    This paper is a report of 14 C-PCB distribution series in animals. We reported the results of the distribution of 14 C-PCB from birds, fish and shell in the previous experiments, and we have obtained some results from present experiment. This time interperito neal injection of 14 C-PCB solution was carried to mice, and the results were as follows; Excretion of 14 C-PCB as radioactivity was at its maximum about 6 hr. after medication. Excretive ratio was 87.20% for 24 hr, but 72.43% of radioactivity was excreted within 12hr. The result of radiopaperchromatography showed that 14 C-PCB was not changeable in the fecus after medication, being Rf = 0.92 in comparison with standard 14 C-PCB. 14 C-PCB distributed throughout the body of mice in 24 hr. and at least remained over till 480 hr. in adipose tissues of mice after single medication. (auth.)

  16. Determination of one-dimensional distribution of 14C-labelled compounds

    International Nuclear Information System (INIS)

    Rexa, R.; Kron, I.; Kralik, P.; Tykva, R.

    1988-01-01

    Three methods used for the determination of one-dimensional distribution of 14 C-labelled compounds are compared: measurement with position-sensitive detector (LB 282/511), liquid scintillation counting (LSC), and autoradiography with densitometric quantification. For a mutual comparison of these methods samples of blood serum were used, in which the fractional esterification rate (FER) was determined by means of LCAT Test. The agreement of the methods of FER determination on the basis of the measurement with LB 282/511 or LSC was checked. In the case of autoradiography a correction for non-linearity between the blackening and the number of β-particles striking the area unit was necessary. (author) 5 refs.; 5 figs

  17. Quantitative film detection of 3H and 14C in polyacrylamide gels by fluorography

    International Nuclear Information System (INIS)

    Laskey, R.A.; Mills, A.D.

    1975-01-01

    Methods which use the scintillator PPO to record film images of 3 H in chromatograms and polyacrylamide gels (fluorography) have been described elsewhere. This paper demonstrates that pre-exposure of the film to a brief flash of light greatly increases the sensitivity of fluorography. Pre-exposure also permits quantitative interpretation of the film image, because it corrects the non-linear relationship between redioactivity of the sample and absorbance of the film image. Therefore the distribution of radioactivity in the sample is accurately represented by micro-densitometry of the image obtained on pre-exposed film. Using pre-exposed film 300 dis. 3 H/min or 30 dis. 14 C/min can be detected in a band in a gel in a 24-h exposure. The appendix describes revisions and extensions of existing fluorographic procedures, including application to agarose gels and a rapid procedure for recovering PPO for re-use. (orig.) [de

  18. Radioimmunoassay for antigliadin-antibodies using 14C-labelled gliadin

    International Nuclear Information System (INIS)

    Menzel, J.

    1977-01-01

    A sensitive radioimmunoassay for antibodies to gliadin has been developed. Gliadin from wheat gluten was labelled with [1- 14 C]acetic anhydride to a specific activity of 2.6 x 10 6 dpm/mg. Immunological evidence is presented that the antigen was not essentially altered by the labelling procedure. Experimentally-induced antigliadin antibodies or sera of patients with coeliac disease (CD) were reacted with labelled gliadin and the immune complexes formed precipitated by antiglobulin. Precipitating antibodies were determined by incubating CD sera with labelled gliadin and measuring the radioacticity in precipitates formed without the addition of second antibody. Comparison with other methods for the detection of antigliadin antibodies, including immunoelectrophoresis, immunodiffusion and passive hemagglutination indicated that total and precipitating antibodies were determined only by RIA. The assay also provides information on the immunoglobulin class of antigliadin-antibodies present in sera of patients with coeliac disease

  19. Metabolism of 14C-L-arginine and 14C-L-proline in excised burst buds and stem sections of citrus trees (Citrus unshiu Marc.)

    International Nuclear Information System (INIS)

    Kato, Tadashi; Yamagata, Makoto; Tsukahara, Sadao

    1985-01-01

    Arginine and proline, which are the major forms of soluble reserve N, were fed singly in uniformly labelled 14 C-form to excised 2-year-old stem sections with a new shoot, to wood sections, and to burst buds from a 21-year-old satsuma mandarin tree. Metabolism was studied by radioassay and autoradiography. In stem sections with a new shoot, both 14 C-compounds were metabolized to acidic and neutral components, insoluble components, and 14 CO 2 . This conversion occurred to a greater extent in sections fed with arginine than with proline. When 14 C-arginine was fed, the highest 14 C-activity in the cationic fraction of stem sections, bark, wood and new shoots was found in γ-guanidinobutyric acid, followed by γ-aminobutyric acid and proline; low levels of 14 C was also found in ornithine and trace amounts in citrulline. These findings demonstrate that arginine is metabolized by at least two routes: via ornithine and via γ-guanidinobutyric acid. In every organ, the major metabolic products of 14 C-proline were pyrrolidone-5-carboxlic acid, glutamic acid, aspartic acid, asparagine, an unidentified compound (U 5 in Fig. 4), γ-aminobutyric acid and arginine. The basic metabolic pathways in the conversion of Both 14 C-compounds were the same in burst buds, new shoot, bark and wood, although there was a slight difference autoradiographically. (author)

  20. Reviewing the Mid-First Millennium BC {sup 14}C 'warp' using {sup 14}C/bristlecone pine data

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.E., E-mail: retaylor@ucr.edu [Department of Anthropology, University of California, Riverside, Riverside, CA (United States); Cotsen Institute of Archaeology, University of California, Los Angeles, CA (United States); Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory, University of California, Irvine, CA (United States); Southon, John [Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory, University of California, Irvine, CA (United States)

    2013-01-15

    AMS-based {sup 14}C measurements have been obtained on 53 dendrochronologically-dated Bristlecone pine (Pinus longaeva) wood samples in decadal increments spanning 2300-2750 cal BP with particular interest focused on the decades centered on 2405 cal BP and 2625 cal BP. In general, there is overall agreement with the current IntCal04/09 consensus calibration curve for this period. For the 2400-2410 cal BP interval, our Bristlecone-based {sup 14}C value is consistent with the {sup 14}C value obtained by Belfast on Irish oak for that decade but not on German oak values obtained by Seattle. Our {sup 14}C value for the 2620-2630 cal BP interval is consistent with the German oak (Heidelberg)-based {sup 14}C decadal value. The {sup 10}Be-based reconstruction of {sup 14}C variations over the 2620-2630 cal BP interval also supports the Heidelberg data although clearly additional clarifications are required before the current tree ring-based {sup 14}C and ice core-based {sup 10}Be data for this interval can be accurately interpreted and valid inferences obtained.

  1. The ocular distribution of 14C-labeled bromfenac ophthalmic solution 0.07% in a rabbit model

    Directory of Open Access Journals (Sweden)

    Baklayan GA

    2014-09-01

    Full Text Available George A Baklayan, Mauricio Muñoz Bausch + Lomb, Irvine, CA, USA Purpose: To evaluate the ocular distribution of an advanced formulation of bromfenac ophthalmic solution. Two studies were conducted in rabbits: 1 a 12-hour parallel-group study comparing the ocular distribution of 14C-bromfenac ophthalmic solution 0.07%, pH 7.8 with that of 14C-bromfenac ophthalmic solution 0.09%, pH 8.3, and 2 a 24-hour study evaluating the ocular distribution of 14C-bromfenac ophthalmic solution 0.07%, pH 7.8.Methods: In the 12-hour study, rabbits were randomized to receive 50 µL of 14C-bromfenac 0.07%, pH 7.8 or 50 µL 14C-bromfenac 0.09%, pH 8.3 in one eye, whereas, in the 24-hour, study both eyes received 50 µL of 14C-bromfenac 0.07%, pH 7.8. Ocular tissues were collected at 1, 2, 4, 8, 12 (both studies and 24 hours (second study only following drug instillation, and tissue radioactivity was determined using liquid scintillation chromatography. Results: Measureable levels of bromfenac were observed in all ocular tissues, with the exception of vitreous humor, regardless of formulation. In the 12-hour study, high concentrations of 14C-bromfenac were found in the sclera, followed by the iris/ciliary body, aqueous humor, choroid, retina, and lens. There was no significant difference between the bromfenac 0.07%, pH 7.8 and bromfenac 0.09%, pH 8.3 formulations in any 14C-bromfenac tissue levels at any time point, with the exception of in sclera at 2 hours post-instillation (0.451 µg eq/g versus 0.302 µg eq/g, respectively, P<0.001. There was also no significant difference in the total amount of 14C-bromfenac in the tissues evaluated following instillation of the two formulations. In the 24-hour study evaluating bromfenac 0.07%, pH 7.8 only, high concentrations of 14C-bromfenac were found 1 hour post-instillation in the cornea (2.402 µg eq/g and conjunctiva (1.049 µg eq/g, two tissues not evaluated in the 12-hour study. The rank order of 14C

  2. Assessments of long-term effects of CO2 and 14C: Various energy scenarios

    International Nuclear Information System (INIS)

    Matthies, M.; Paretzke, H.G.

    1982-01-01

    A non-linear model for the global carbon cycle has been developed and applied for prognostic assessment of concentrations of CO 2 from the combustion of fossil fuel and of radiocarbon released from facilities of the nuclear fuel cycle. The model is built up from two boxes for the atmosphere (stratosphere, troposphere), three boxes for the ocean (mixed surface layer, deep sea and sediments), and two boxes for the biosphere (short-and long-lived biota) with non-linear troposphere-biota and troposphere-ocean surface layer exchange rates and linear fluxes between the other reservoirs. Two different models are used for the man-made reduction of the biomass: (a) no deforestation function, and (b) slightly growing deforestation function. The three scenarios considered are: (I) annual energy growth rates of 2% and 4%, no nuclear power; (II) an upper, lower and medium estimate of replacement of fossil fuels by nuclear power. In addition, two assumptions concerning the decontamination of 14 C in the nuclear power plant effluents were made: one in which 14 C is released completely, and one with a decontamination factor of 4. Assuming logistic source functions for the increase of fossil-fuel combustion and an exponential growth of nuclear power until the year 2020, by around 2100 the CO 2 concentration of the troposphere will reach concentrations twice to five times as high as the pre-industrial level. Various environmental effects of this increasing CO 2 level are briefly discussed. The specific 14 C activity of the atmosphere is decreased. Up to the year 2200, the specific activity will be lower than the pre-industrial level. The individual lifetime dose commitments (70 years) are found between 0.85 and 0.45 mSv (pre-industrial value: 0.73 mSv)

  3. Longevity and growth of Acacia tortilis; insights from 14C content and anatomy of wood.

    Science.gov (United States)

    Andersen, Gidske L; Krzywinski, Knut

    2007-06-15

    Acacia tortilis is a keystone species across arid ecosystems in Africa and the Middle East. Yet, its life-history, longevity and growth are poorly known, and consequently ongoing changes in tree populations cannot be managed in an appropriate manner. In other arid areas parenchymatic bands marking growth zones in the wood have made dendrochronological studies possible. The possibilities for using pre- and post-bomb 14C content in wood samples along with the presence of narrow marginal parenchymatic bands in the wood is therefore tested to gain further insight into the age, growth and growth conditions of A. tortilis in the hyper-arid Eastern Desert of Egypt. Based on age scenarios and the Gompertz growth equation, the age of trees studied seems to be from 200 up to 650 years. Annual radial growth estimated from calibrated dates based on the post-bomb 14C content of samples is up to 2.4 mm, but varies both spatially and temporally. Parenchymatic bands are not formed regularly. The correlation in band pattern among trees is poor, both among and within sites. The post-bomb 14C content of A. tortilis wood gives valuable information on tree growth and is required to assess the age scenario approach applied here. This approach indicates high longevities and slow growth of trees. Special management measures should therefore be taken at sites where the trend in tree population size is negative. The possibilities for dendrochronological studies based on A. tortilis from the Eastern Desert are poor. However, marginal parenchymatic bands can give insight into fine scale variation in growth conditions and the past management of trees.

  4. Longevity and growth of Acacia tortilis; insights from 14C content and anatomy of wood

    Directory of Open Access Journals (Sweden)

    Krzywinski Knut

    2007-06-01

    Full Text Available Abstract Background Acacia tortilis is a keystone species across arid ecosystems in Africa and the Middle East. Yet, its life-history, longevity and growth are poorly known, and consequently ongoing changes in tree populations cannot be managed in an appropriate manner. In other arid areas parenchymatic bands marking growth zones in the wood have made dendrochronological studies possible. The possibilities for using pre- and post-bomb 14C content in wood samples along with the presence of narrow marginal parenchymatic bands in the wood is therefore tested to gain further insight into the age, growth and growth conditions of A. tortilis in the hyper-arid Eastern Desert of Egypt. Results Based on age scenarios and the Gompertz growth equation, the age of trees studied seems to be from 200 up to 650 years. Annual radial growth estimated from calibrated dates based on the post-bomb 14C content of samples is up to 2.4 mm, but varies both spatially and temporally. Parenchymatic bands are not formed regularly. The correlation in band pattern among trees is poor, both among and within sites. Conclusion The post-bomb 14C content of A. tortilis wood gives valuable information on tree growth and is required to assess the age scenario approach applied here. This approach indicates high longevities and slow growth of trees. Special management measures should therefore be taken at sites where the trend in tree population size is negative. The possibilities for dendrochronological studies based on A. tortilis from the Eastern Desert are poor. However, marginal parenchymatic bands can give insight into fine scale variation in growth conditions and the past management of trees.

  5. Formation and bio release of bound residues of [14 C]-lindane and [14 C]-parathion in two Brazilian soils

    International Nuclear Information System (INIS)

    Andrea, M.M. de.

    1992-01-01

    This work studied the extractable and bound residues formation of 14 C-lindane and 14 C-parathion immediately after application and after 3 months of interaction of the pesticides with the soils. Metabolism, bio release, and the possible bioavailability of bound residues were studied by employing bio meter flasks which allowed a relative comparison of the behaviour of the two different 14 C-pesticides, by a balance of the applied or present radiocarbon in the soils after the bio tests. (author)

  6. Delta sup(14)C, sigma CO sub(2) salinity of the western Indian Ocean deep waters: Spatial and temporal variations

    Digital Repository Service at National Institute of Oceanography (India)

    Somayajulu, B.L.K.; Bhushan, R.; Narvekar, P.V.

    ppt, as revealed by the GEOSECS data (1977-78). The delta sup(14)C-sigma CO sub(2)-salinity relationships show better correlation in the western sector. High biological productivity induced changes and corrosive deepwaters could account for sigma CO...

  7. Changes in solar activity and Holocene climatic shifts derived from 14C wiggle-match dated peat deposits

    NARCIS (Netherlands)

    Mauquoy, Dmitri; Geel, Bas van; Blaauw, Maarten; Speranza, Alessandra; Plicht, Johannes van der

    2004-01-01

    Closely spaced sequences of accelerator mass spectrometer (AMS) 14C dates of peat deposits display century-scale wiggles which can be fitted to the radiocarbon calibration curve. By wiggle-matching such sequences, high-precision calendar age chronologies can be generated which show that changes in

  8. The remarkable metrological history of 14C dating: from ancient Egyptian artifacts to particles of soot and grains of pollen

    International Nuclear Information System (INIS)

    Currie, L.A.

    2002-01-01

    . Sensitivity enhancement by some six orders of magnitude was the result, where 14 C atoms are measured directly by accelerator mass spectrometry (AMS), in place of beta particle (decay) counting. (Apart from differences in detection efficiency, the relative sensitivity derives from the first order relationship between the nuclear disintegration rate and the ratio of the 14 C atom concentration to the mean life.) The resultant ability to date ca. 100 μg of carbon has fostered major developments in 'molecular dating' (e.g., via GC/AMS) that have had a profound impact on artifact dating accuracy, and provided new insights into the sources, transport, and age of individual carbonaceous species in the environment. The talk concluded with some current applications of the advanced 14 C metrology, such as the dating of individual amino acids in prehistoric bones, and efforts to extract the recent history of fossil and biomass burning from soot particles trapped in polar and mid-latitude ice cores. (author)

  9. Novel charge sensitive preamplifier without high-value feedback resistor

    International Nuclear Information System (INIS)

    Xi Deming

    1992-01-01

    A novel charge sensitive preamplifier is introduced. The method of removing the high value feedback resistor, the circuit design and analysis are described. A practical circuit and its measured performances are provided

  10. 13C and 14C measurements on lake sediments of the Grosser Ploener See

    International Nuclear Information System (INIS)

    Erlenkeuser, H.; Willkomm, H.

    1979-01-01

    Radiocarbon age and 13 C content of organic and inorganic carbon fractions were measured for two sediment cores from the Grosser Ploener See (N-Germany), comprising the whole post-glacial. As compared to the age of the pollen stages, the 14 C age of the organic fraction is seen to show a hard-water effect of about 1000 years throughout the sediment column, indicating a constant recent activity of the lake bicarbonate of about 92% of the standard recent activity during the history of the lake. From the age of sediment samples corrected for hard water effect and for 14 C variations of the atmosphere the sedimentation rate is found to increase from 0.4 to 0.8 mm/year in the pre-Christian era to as high as 10 mm/year during the last 7 centuries. In the lower layers of the sediment, the 14 C content of the marl fraction corresponds to that of the organic component, indicating the autochthonous origin of these carbonates. During the last 2 1 /2 millenia, however, its 14 C content is too small by 10 to 30%, probably reflecting an allochthonous admixture. Increasing rate of sedimentation along with the growing accumulation of allochthonous minerals probably reflect the agricultural activity of man. It is associated with an increasing supply of nutrients to the lake particularly since a man-made rise of the water level at A.D. 1256, resulting in an enhanced rate of primary production which could be recognized from the stable carbon isotope ratios of both the sedimentary organic carbon and carbonate fraction. According to these results, the contribution of planktogenic organic matter to the sediments as compared to the supply of plant litter from the litoral zones is steadily increasing during the history of the lake and becomes the dominating part since the lake level risc in the Middle Ages. According to the 13 C/ 12 C-ratios, the carbonates of the sediment appear to have been precipitated preferentially in the litoral zones. (orig./MG) [de

  11. Double labeling autoradiography. Cell kinetic studies with 3H- and 14C-thymidine

    International Nuclear Information System (INIS)

    Schultze, B.

    1981-01-01

    Examples of the multiple applicability of the double labeling method with 3 H- and 14 C-TdR are demonstrated. Double labeling with 3 H- and 14 C-TdR makes it possible to determine the cycle and its phases with high precision by modifying the usual percent labeled mitoses method with a single injection of 3 H-TdR. In addition, data is provided on the variances of the transit times through the cycle phases. For example, in the case of the jejunal crypt cells of the mouse, the transit times through successive cycle phases are uncorrelated. In the case of glial cells the double labeling method provides cell kinetic parameters despite the paucity of proliferating glial cells. In the adult untreated animal, glial cell mitoses are so rare that the percent labeled mitoses method can not be utilized. However, the S-phase duration can be measured by double labeling and the cycle time can be determined by the so-called method of labeled S phases. With the latter method the passage through the S phase of the 3 H-TdR-labeled S phase cells can be registered by injecting 14 C-TdR at different time intervals following 3 H-TdR application. In this way an S-phase duration of about 10 hr and a cycle time of about 20 hr was found for glial cells in the adult untreated mouse. An exchange of glial cells between the growth fraction and the nongrowth fraction has also been shown by double labeling. A quite different application of the double labeling method with 3H- and 14 C-TdR is the in vivo study of the cell cycle phase-specific effect of drugs used in chemotherapy of tumors. The effect of vincristine on these cells has been studied. Vincristine affects cells in S and G2 in such a manner that they are arrested during the next metaphase and subsequently become necrotic. It has no effect on G1 cells

  12. The compact 14C AMS facility of Paleo Labo Co., Ltd., Japan

    International Nuclear Information System (INIS)

    Kobayashi, Koichi; Niu, Etsuko; Itoh, Shigeru; Yamagata, Hideki; Lomtatidze, Zaur; Jorjoliani, Ineza; Nakamura, Kentaro; Fujine, Hisashi

    2007-01-01

    A compact AMS system was installed by a private company in Japan for a 14 C dating business. Since this system was designed to be very compact with a low voltage accelerator, it has unique features compared to larger AMS systems. For example, the stripper gas pressure has to be maintained at a high level to dissociate molecular ions. However, it cannot be too high because ion transmission decreases at higher stripper gas pressures due to increased angular straggling of the ions scattered by the high density stripper gas. The optimum pressure of the stripper gas for the lowest background and the highest transmission was investigated. With all the features of the compact system, the produced measurements can be of quite high precision. In the ten months after the installation of the equipment in November 2004, we have measured more than 1400 dating samples

  13. Analysis of 14C and 13C in teeth provides precise birth dating and clues to geographical origin.

    Science.gov (United States)

    Alkass, K; Buchholz, B A; Druid, H; Spalding, K L

    2011-06-15

    The identification of human bodies in situations when there are no clues as to the person's identity from circumstantial data, poses a difficult problem to the investigators. The determination of age and sex of the body can be crucial in order to limit the search to individuals that are a possible match. We analyzed the proportion of bomb pulse derived carbon-14 ((14)C) incorporated in the enamel of teeth from individuals from different geographical locations. The 'bomb pulse' refers to a significant increase in (14)C levels in the atmosphere caused by above ground test detonations of nuclear weapons during the cold war (1955-1963). By comparing (14)C levels in enamel with (14)C atmospheric levels systematically recorded over time, high precision birth dating of modern biological material is possible. Above ground nuclear bomb testing was largely restricted to a couple of locations in the northern hemisphere, producing differences in atmospheric (14)C levels at various geographical regions, particularly in the early phase. Therefore, we examined the precision of (14)C birth dating of enamel as a function of time of formation and geographical location. We also investigated the use of the stable isotope (13)C as an indicator of geographical origin of an individual. Dental enamel was isolated from 95 teeth extracted from 84 individuals to study the precision of the (14)C method along the bomb spike. For teeth formed before 1955 (N=17), all but one tooth showed negative Δ(14)C values. Analysis of enamel from teeth formed during the rising part of the bomb-spike (1955-1963, N=12) and after the peak (>1963, N=66) resulted in an average absolute date of birth estimation error of 1.9±1.4 and 1.3±1.0 years, respectively. Geographical location of an individual had no adverse effect on the precision of year of birth estimation using radiocarbon dating. In 46 teeth, measurement of (13)C was also performed. Scandinavian teeth showed a substantially greater depression in

  14. {sup 14}C emission from Swedish nuclear power plants and its effect on the {sup 14}C levels in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Stenstroem, K.; Erlandsson, Bengt; Hellborg, R.; Kiisk, M.; Persson, Per [Lund Univ. (Sweden). Dept. of Nuclear Physics; Mattsson, Soeren; Thornberg, C. [Lund Univ., Malmoe (Sweden). Dept. of Radiation Physics; Skog, G. [Lund Univ. (Sweden). Dept. of Quaternary Geology

    2000-02-15

    The radionuclide {sup 14}C is produced in all types of nuclear reactors mainly by neutron induced reactions in oxygen ({sup 17}O), nitrogen ({sup 14}N) and carbon ({sup 13}C). Part of the {sup 14}C created is continuously released during normal operation as airborne effluents in various chemical forms (such as CO{sub 2}, CO and hydrocarbons) to the surroundings. Because of the biological importance of carbon and the long physical half-life of {sup 14}C, it is of interest to measure the releases and their incorporation into living material. The {sup 14}C activity concentrations in annual tree rings and air around two Swedish nuclear power plants (Barsebaeck and Forsmark) as well as the background {sup 14}C activity levels from two reference sites in southern Sweden during 1973-1996 are presented in this report. In order to verify the reliability of the method some investigations have been conducted at two foreign nuclear sites, Sellafield fuel reprocessing plant in England, and Pickering nuclear generating station in Canada, where the releases of {sup 14}C are known to be substantial. Furthermore, results from some measurements in the vicinity of Paldiski submarine training centre in Estonia are presented. The results of the {sup 14}C measurements of air, vegetation and annual tree rings around the two Swedish nuclear power plants show very low enhancements of {sup 14}C, if at all above the uncertainty of the measurements. Even if the accuracy of the measurements of the annual tree rings is rather good (1-2%) the contribution of {sup 14}C from the reactors to the environment is so small that it is difficult to separate it from the prevailing background levels of {sup 14}C . This is the case for all sampling procedures: in air and vegetation as well as in annual tree rings. Only on a few occasions an actual increase is observed. However, although the calculations suffer from rather large uncertainties, the calculated release rate from Barsebaeck is in fair agreement

  15. 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

  16. UDP-[14C]glucose-labelable polypeptides from pea: Possible components of glucan synthase I activity

    International Nuclear Information System (INIS)

    Ray, P.M.; Dhugga, K.S.; Gallaghar, S.R.

    1989-01-01

    A membrane-bound polypeptide doublet of about 40 kD can be rapidly labeled with UDP-[ 14 C]glucose under the assay conditions for glucan synthase I (GS-I). Label seems covalently bound, and chases when unlabeled UDPG is added; it might represent a covalent intermediate in polysaccharide synthesis. Labeling and GS-I activity show several common features: they co-sediment with Golgi membranes in sucrose gradients; they depend similarly on Mg 2+ or Mn 2+ (not Ca 2+ ); they decrease dramatically from stem apex to base, and are higher in epidermis than internal tissue; they show similar sensitivities to several inhibitors. But the doublet still labels after polysaccharide-synthesizing activity has been destroyed by Triton X-100. The doublet polypeptides might be glucosyl tranferases whose ability to transfer glucose units to a glucan chain is detergent-sensitive, but to accept glucose from UDPG is not; or they might be detergent-insensitive primary glucose acceptors, from which a distinct, detergent-sensitive transferase(s) move(s) these units to glucan chains

  17. The distribution of [14C]acrylamide in rainbow trout studied by whole-body autoradiography

    International Nuclear Information System (INIS)

    Waddell, W.J.; Lech, J.J.; Marlowe, C.; Kleinow, K.M.; Friedman, M.A.

    1990-01-01

    The distribution of [2,3- 14 C]acrylamide was studied in fingerling rainbow trout by whole-body autoradiography. Fish weighing approximately 7 g were injected ip with 3.2 mg/kg [ 14 C]acrylamide (0.1 microCi/g). One group of fish was kept in a fresh flowing water tank and frozen in dry ice/hexane 22 hr after injection; another group was placed in a separate tank of fresh flowing water and frozen 120 hr after treatment. A third group of fish served as nontreated controls. The autoradiographs of the fish at 22 hr show the highest concentration of radioactivity in the kidney, urinary bladder, blood, gallbladder, intestinal contents, and lens of eye. Lesser amounts of radioactivity are seen in the CNS, liver, and gills. Very low concentrations are seen in muscle. By 120 hr the only high concentrations are seen in gallbladder and lens of the eye. Lesser amounts are seen in the sclera, vertebrae, CNS, kidney, wall of intestine, and discrete spots in subcutaneous tissue presumed to be chromatophores. Low amounts are seen in muscle, the tissue usually consumed by man

  18. Metabolic fate of [U-14C]pentachlorophenol in a lactating dairy cow

    International Nuclear Information System (INIS)

    Kinzell, J.H.; McKenzie, R.M.; Olson, B.A.; Kirsch, D.G.; Shull, L.R.

    1985-01-01

    A lactating Holstein-Friesen dairy cow was administered a single oral dose of [U- 14 C]pentachlorophenol (PCP). To better simulate chronic exposure conditions on a typical dairy farm, the cow was fed 0.2 mg/kg body wt/day technical PCP for 95 days prior to [U- 14 C]PCP administration and for the 4 days postadministration. Both absorption and elimination of PCP obeyed first-order kinetics and had half-lives of 4.3 and 43 h, respectively. Over the 76-h postadministration, 75% of the radiolabel was eliminated in urine, 5% in milk, and 5% in feces. The radiolabel was distributed widely into various tissues, but the highest levels were in liver, kidneys, and lungs. Skeletal muscle and adipose tissue contained among the lowest levels. In milk, the fat fraction contained the greatest amount of the radiolabel but the whey fraction represented the largest pool (62.2%). In whey and casein, both conjugated and unconjugated forms were quantified. There was no evidence of phase 1 metabolism of PCP, whereas phase 2 metabolism (conjugation) was highly evident. In urine, two-thirds of the PCP was present in a conjugated form, whereas in serum about 80% was present as unconjugated PCP. These data suggest that efficient conjugation and elimination of PCP prevent its accumulation in cattle tissues

  19. 14C age of the Satsunai pumice bed, Noboribetsu City, SW Hokkaido, Japan

    International Nuclear Information System (INIS)

    Kawachi, Shinpei; Matsui, Masaru; Miyasaka, Shogo; Akamatsu, Morio; Kasugai, Akira.

    1980-01-01

    A sample of carbonized fallen tree piece (Picea or Pinus; diameter 5 cm and length 15 cm) was discovered in a crop in the Noboribetsu pumice flow deposit, where fossil-rootless fumaroles had been found recently. It existed in the loam layer immediately above the Satsunai pumice bed covering the Noboribetsu formation and the fumaroles below it. Its 14 C age was determined to be 11,330 +- 320 Y.B.P. Though the distribution and eruption source of Satsunai pumice bed are still unknown, the 14 C age has significance as follows in the Quaternary chronology. (1) The Satsunai pumice bed is important as a pumice bed indicating the boundary between the pleistocene and the Recent epoch. (2) By means of the Satsunai pumice bed, the age of upper Noboribetsu formation is given. (3) As there is no high bench deposit on the Noboribetsu pumice flow deposit, the time gap may be small between the Satsunai pumice bed and the Noboribetsu formation below it. (J.P.N.)

  20. A high-sensitivity neutron counter and waste-drum counting with the high-sensitivity neutron instrument

    International Nuclear Information System (INIS)

    Hankins, D.E.; Thorngate, J.H.

    1993-04-01

    At Lawrence Livermore National Laboratory (LLNL), a highly sensitive neutron counter was developed that can detect and accurately measure the neutrons from small quantities of plutonium or from other low-level neutron sources. This neutron counter was originally designed to survey waste containers leaving the Plutonium Facility. However, it has proven to be useful in other research applications requiring a high-sensitivity neutron instrument

  1. Quality of Graphite Target for Biological/Biomedical/Environmental Applications of 14C-Accelerator Mass Spectrometry

    Science.gov (United States)

    2010-01-01

    Catalytic graphitization for 14C-accelerator mass spectrometry (14C-AMS) produced various forms of elemental carbon. Our high-throughput Zn reduction method (C/Fe = 1:5, 500 °C, 3 h) produced the AMS target of graphite-coated iron powder (GCIP), a mix of nongraphitic carbon and Fe3C. Crystallinity of the AMS targets of GCIP (nongraphitic carbon) was increased to turbostratic carbon by raising the C/Fe ratio from 1:5 to 1:1 and the graphitization temperature from 500 to 585 °C. The AMS target of GCIP containing turbostratic carbon had a large isotopic fractionation and a low AMS ion current. The AMS target of GCIP containing turbostratic carbon also yielded less accurate/precise 14C-AMS measurements because of the lower graphitization yield and lower thermal conductivity that were caused by the higher C/Fe ratio of 1:1. On the other hand, the AMS target of GCIP containing nongraphitic carbon had higher graphitization yield and better thermal conductivity over the AMS target of GCIP containing turbostratic carbon due to optimal surface area provided by the iron powder. Finally, graphitization yield and thermal conductivity were stronger determinants (over graphite crystallinity) for accurate/precise/high-throughput biological, biomedical, and environmental14C-AMS applications such as absorption, distribution, metabolism, elimination (ADME), and physiologically based pharmacokinetics (PBPK) of nutrients, drugs, phytochemicals, and environmental chemicals. PMID:20163100

  2. 14C-labeled diesel exhaust particles: chemical characteristics and bioavailability studies

    International Nuclear Information System (INIS)

    Sun, J.D.; Wolff, R.K.; Dutcher, J.S.; Brooks, A.L.

    1981-01-01

    Little is known about the deposition, retention and biological fate of the organic compounds associated with diesel exhaust particles. In the studies reported here, a one-cylinder diesel engine was operated on diesel fuel spiked with 14 C-benzene, 14 C-hexadecane or 14 C-dotriacontane to generate 14 C-labeled diesel exhaust. Approximately 1% of the exhaust radioactivity was associated with the particulate phase of diesel exhaust. Chemical fractionation of the particle extract showed the 14 C to be present in each of the various chemical class fractions collected. Serum removed approx. 60% of the dichloromethane extractable radioactivity from these diesel particles while saline removed only approx. 6%. This suggested that the organic compounds may be removed from diesel particles in vivo. Future inhalation exposures of rodents to 14 C-labeled diesel exhausts are planned to gain additional information on the health risk of human exposure to diesel exhaust

  3. Study on "1"4C content in post-irradiation graphite spheres of HTR-10

    International Nuclear Information System (INIS)

    Wang Shouang; Pi Yue; Xie Feng; Li Hong; Cao Jianzhu

    2014-01-01

    Since the production mechanism of the "1"4C in spherical fuel elements was similar to that of fuel-free graphite spheres, in order to obtain the amount of "1"4C in fuel elements and graphite spheres of HTR-10, the production mechanism of the "1"4C in graphite spheres was studied. The production sources of the "1"4C in graphite spheres and fuel elements were summarized, the amount of "1"4C in the post-irradiation graphite spheres was calculated, the decomposition techniques of graphite spheres were compared, and experimental methods for decomposing the graphite spheres and preparing the "1"4C sample were proposed. The results can lay the foundation for further experimental research and provide theoretical calculations for comparison. (authors)

  4. Translocation of 14C-photosynthates under normal and moisture stress conditions in finger millet (Eleusine coracana) gaertin

    International Nuclear Information System (INIS)

    Udayakumar, M.; Rama Rao, S.; Krishna Sastry, K.S.

    1981-01-01

    Translocation of photosynthates into different sinks was studied following feeding a single leaf with 14 CO 2 in 40 day old stressed and non-stressed plants of Eleusine coracana. The rate of efflux of 14 C-photosynthates was twice as much in non-stressed plants compared to stressed plants. Young developing leaves, stem apex and stem which are the potential sinks under non-stressed conditions received very little activity under stress conditions. Percent activity in the roots was enhanced under stress suggesting the pattern of translocation was altered under stress conditions. In the plants subjected to moisture stress, after feeding with 14 CO 2 the rate of efflux of 14 C-photosynthates from the fed leaf decreased and the pattern of translocation was altered. Though the effect of stress seems to be directly on the translocation system, the photosynthetic rate appears to be more sensitive to stress than translocation. (author)

  5. Synthesis of 20-14C 3β-hydroxy-5β-pregnan-20-one

    International Nuclear Information System (INIS)

    Garraffo, H.M.; Gros, E.G.

    1982-01-01

    20 - 14 C 3β-hydroxy-5β-pregnan-20-one was synthesised by condensing 3β-acetoxy-5β-androstan-17-one with potassium 14 C cyanide to produce cyanohydrin. This was dehydrated and the resulting unsaturated nitrile treated with methylmagnesiumiodide to produce hydroxypregnenone. Hydrogenation of this gave 14 C 3β-hydroxy-5β-pregnan-20-one. (U.K.)

  6. Dissipation and leaching of 14C-monocrotophos in soil columns

    International Nuclear Information System (INIS)

    Vig, K.; Singh, D.K.; Agarwal, H.C.

    2001-01-01

    Dissipation and leaching of 14 C-monocrotophos was studied in the field. Two sets of PVC cylinders were used - one set received only 14 C monocrotophos and the other received 14 C-monocrotophos along with dimethoate, deltamethrin, endosulfan, cypermethrin and 1.06 mg unlabelled monocrotophos. Both setups showed a similar pattern of dissipation with a half-life of 277.2 days. Leaching of monocrotophos was observed into the 30cm soil layer. (author)

  7. 14C-labeling of isomeric perfluoroalkyl carboxanilide mixtures via electrofluorination

    International Nuclear Information System (INIS)

    Gajewski, R.P.; Terando, N.H.; Berard, D.F.

    1988-01-01

    Electrofluorination of benzoyl chloride-ring-UL- 14 C produced an isomer mixture of cyclic C 6 F 11 carbonyl fluorides, principally 1,2,2,3,3,4,4,5,5,6,6-undecafluorocyclohexane-ring-UL- 14 C carbonyl fluoride, which was derivatized with 2-bromo-4-nitroaniline and triethyl amine. The resultant carboxanilide mixture is designated as EL-499 labeled with 14 C in the perfluoro alkyl ring for use in metabolic studies. (author)

  8. Nd2Fe14C-based magnet with better permanent magnetic properties prepared by a simple mechanochemical method

    Science.gov (United States)

    Geng, Hongmin; Ji, Yuan; Zhang, Jingjing; Gao, Yuchao; Yan, Yu; Wang, Wenquan; Su, Feng; Du, Xiaobo

    2017-11-01

    Nd2Fe14C-based magnet is prepared by a mechanochemical method, namely high-energy ball-milling Nd2Fe11Bx (x = 0-0.15) alloy in heptane (C7H16), followed by annealing to 850 °C in vacuum. Under the action of high-energy ball-milling, Nd2Fe11Bx react with heptane to form NdH2+δ, Fe-(CB), C, etc. H2 is released and Nd2Fe17, Nd2Fe17Cx (x = 0-3), Nd2Fe14C, Nd carbides and α-Fe are formed in the subsequent annealing. C amount depends on ball-milling time t. Long time ball milling or high C content suppresses the formation of 2:17 phase and favors the formation of 2:14:1 phase in the final products. Excessive ball-milling results in the quick increase of α-Fe. The maximum of magnetically hard Nd2Fe14C is obtained at t = 4 h. For Nd2Fe11 samples, there exists considerable quantity of Nd carbides and α-Fe phase appears earlier and increases rapidly with extending the ball-milling time t. The addition of B element shortens the ball-milling time of the formation of maximum Nd2Fe14C and prominently suppresses the formation of Nd carbide and α-Fe. The optimum magnetic properties, coercivity iHc of 1193.7 kA/m, remanence Mr of 580.9 kA/m, maximum magnetic energy product (BH)max of 91.7 kJ/m3 is approaching to its theoretic value of 99.2 kJ/m3 for isotropic Nd2Fe14C magnet, are obtained in Nd2Fe11B0.06 alloy ball milled for 3.5 h.

  9. Techniques of tandem accelerator mass spectrometry and their applications to 14C measurements

    International Nuclear Information System (INIS)

    Nakamura, Toshio; Nakai, Nobuyuki; Furukawa, Michiaki

    1990-01-01

    A tandem accelerator mass spectrometer, named Tandetron was installed at Nagoya University in 1982 for 14 C measurement. The Tandetron spectrometer consists of a Cs sputter ion source to produce negative carbon ions, a Schenkel-type 2.2 MV tandem accelerator, an ion-beam analyzing apparatus with a charge-energy selector and mass spectrometer, and a heavy ion detector to identify and count 14 C 3+ ions from various background ions. The 14 C concentrations in pine needles, sampled at the Higashiyama Campus of Nagoya University, have been measured since 1984. The present article describes some of the measurements of 14 C in pine needles, focusing on the annual changes in the Δ 14 C value of atmospheric CO 2 , and on the effect upon 14 C concentrations for pine needles of a local 14 CO 2 emission from incineration of radioactive organic solvent wastes containing 14 C, at the Radioisotope Center in the Higashiyama Campus. The pine needles at some locations seemed to be influenced by local artificial CO 2 emission. The Δ 14 C values increased noticeably from 1956 to 1964 as a result of artificial 14 C produced in nuclear weapon tests. (N.K.)

  10. Fate of [14C]arsanilic acid in pigs and chickens

    International Nuclear Information System (INIS)

    Aschbacher, P.W.; Feil, V.J.

    1991-01-01

    Arsanilic acid uniformly labeled with 14 C in the benzene ring was used to determine the metabolic fate of oral arsanilic acid in pigs and chickens. Arsanilic acid was well absorbed in both species, and urine was the predominant route of excretion. The bile was a minor ( 14 C, respectively). Only 25% of the 14 C in pig feces was extractable, and no metabolites could be isolated. Arsanilic acid was the only radioactive compound isolated from urine of colostomized roosters, and there was no suggestion of other metabolites from the isolation scheme employed. No attempt was made to isolate 14 C compounds in feces from colostomized roosters or in excreta from normal roosters

  11. Synthesis of the muscle relaxant [14C]L-637,510

    International Nuclear Information System (INIS)

    O'Connor, S.P.; Ellsworth, R.L.; Gatto, G.

    1991-01-01

    The synthesis of (E)-3-(9-chloro-5,6-dihydro-11H-pyrolo(2,1-b)(3)-benzazepin-11-ylidene)-N,N-dimethyl-1- [3- 14 C]-propanamine (Z)-2-butenedioate(1:1) ([ 14 C]L-637,510), a potential muscle relaxant product for which 14 C-labeling was required for metabolism studies, is described. Introduction of the label in the 3-position of the propanamine side chain was accomplished in eight steps from sodium [ 14 C]cyanide with an overall radiochemical yield of 4.8%. (author)

  12. The synthesis of [U-14C phenyl] LS 840606, an agricultural fungicide

    International Nuclear Information System (INIS)

    Madegard, G.; Mestre, P.; Raimond, P.; Noel, J.-P.

    1995-01-01

    2,2',4'-Trichloro-[ring U- 14 C]acetophenone was the key intermediate of this synthesis patterned after the industrial route. An unexpected poor yield was observed during the preparation by the Friedel-Crafts reaction of chloroacetyl chloride with 1,3-dichloro-[U- 14 C]benzene, possibly the result of an isotope effect although this poor yield might be explained by other factors. Two routes were checked for the preparation of 1,3-dichloro-[U- 14 C]benzene. The action of CCl 4 with 1,3-dinitro-[U- 14 C]benzene at 280 o C was entailed with explosions. A safer route started from [U- 14 C]aniline via 2,4-dichloro-[ring U- 14 C]acetanilide. Friedel-Crafts reaction with acetyl chloride gave rise in 52% yield to 2',4'-dichloro-[ring U- 14 C]acetophenone which was brominated to 2-bromo-2',4'-dichloro-[ring U- 14 C]acetophenone; was condensed with 2,2-ethylenedioxy)etylmagnesium bromide to compound, was condensed with 1,2,4-triazole then successively treated with HCl:water:dioxane and 2,2,2-trifluoroethanol/HCl. Separation of the two diastereomers by medium pressure liquid chromatography. 7% overall radioactivity yield from [U- 14 C]aniline. Radiochemical purity 99%. (author)

  13. Effect of Cooking on 14C-Chloropyrifos Residues in Stored Faba Beans

    International Nuclear Information System (INIS)

    Mahdy, F.

    2006-01-01

    The effect of cooking on the amount and nature of 14 C-chloropyrifos residues in stored vicia faba beans was studied. faba beans treated with (ethyl-1- 14 C) chloropyrifos insecticide at a dose 15 and 45 mg insecticide/kg seeds and stored for 30 weeks had 50-54% of the actual applied doses inside the grains in the form of extractable and bound 14 C- chloropyrifos residues. Extractable residues in cooked beans included, in addition to the parent insecticide O-analogue, desethyl chloropyrifos and 3,5,6-trichloro pyridinol, as main degradation products of 14 C-chloropyrifos

  14. The synthesis of [U-{sup 14}C phenyl] LS 840606, an agricultural fungicide

    Energy Technology Data Exchange (ETDEWEB)

    Madegard, G.; Mestre, P.; Raimond, P.; Noel, J.-P. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1995-12-01

    2,2`,4`-Trichloro-[ring U-{sup 14}C]acetophenone was the key intermediate of this synthesis patterned after the industrial route. An unexpected poor yield was observed during the preparation by the Friedel-Crafts reaction of chloroacetyl chloride with 1,3-dichloro-[U-{sup 14}C]benzene, possibly the result of an isotope effect although this poor yield might be explained by other factors. Two routes were checked for the preparation of 1,3-dichloro-[U-{sup 14} C]benzene. The action of CCl{sub 4} with 1,3-dinitro-[U-{sup 14} C]benzene at 280{sup o}C was entailed with explosions. A safer route started from [U-{sup 14}C]aniline via 2,4-dichloro-[ring U-{sup 14}C]acetanilide. Friedel-Crafts reaction with acetyl chloride gave rise in 52% yield to 2`,4`-dichloro-[ring U-{sup 14}C]acetophenone which was brominated to 2-bromo-2`,4`-dichloro-[ring U-{sup 14}C]acetophenone; was condensed with 2,2-(ethylenedioxy)etylmagnesium bromide to compound, was condensed with 1,2,4-triazole then successively treated with HCl:water:dioxane and 2,2,2-trifluoroethanol/HCl. Separation of the two diastereomers by medium pressure liquid chromatography. 7% overall radioactivity yield from [U-{sup 14}C]aniline. Radiochemical purity 99%. (author).

  15. 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)

  16. Study on transference of assimilate in filling summer maize using isotope 14C

    International Nuclear Information System (INIS)

    Fan Zhongxue; Wang Pu; Liang Zhenxing

    2001-01-01

    The dynamic of assimilate transference from the ear leaf to grain during effective grain filling stage was studied by 14 C tracer. The results showed that the rates of assimilate transportation out of the ear leaf and transference to grain changed very fast. The rate was very big in 4 - 6 hour just after 14 C feeding and decreased with time. The grain which accumulated 14 C-assimilate in a higher rate and got much more 14 C-assimilate in fixed time could develop into larger size

  17. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  18. Mass balance of pent achloroni trobenzene-14c and metabolites in a closed aerated soil plant or soil-system

    International Nuclear Information System (INIS)

    Kamal, M.

    1984-01-01

    Two experiments were carried out with pentachloronitrobenzene- 14 C and soils with and without plants in a closed aerated laboratory system. In both experiments, degradation to 14 CO 2 within 16 or 53 days, respectively, was very low (=0,01% of initially applied 14 C). Volatilization loses were about 15% in the system with plants (16 days) and were negligible in the soil without plants (53 days). The uptake into plants within 16 days was 5.26% of initially applied 14 C(0.86% unchanged parent compound, 3.35% soluble metabolites, and 1.05% unextractable residues); the major portion of soluble metabolites was highly polar conjugates which were not characterized further. The radioactivity left in both soils after 16 or 53 days, respectively, considered of 57 or 37% unchanged parent compound, 10 or 42% soluble metabolites, and 13 or 25% soil-bound residues. In the soil without plants, the following conversion products were identified after 53 days: pentachloroaniline (18.7% of initially applied 14 C), pentachlorthioanisole (17.3%), pentachlorobenzene, and pentachlorophenylmethylsulphoxide (2.6% each). (author)

  19. Dermal absorption and disposition of methoxy (ME), ethoxy- (EE), and butoxy[U-14C]ethanol (BE)

    International Nuclear Information System (INIS)

    Sabourin, P.J.; Medinsky, M.A.; Thurmond, F.; Henderson, R.F.; Birnbaum, L.S.

    1990-01-01

    The glycol ethers (GEs) demonstrate testicular and hemopoietic toxicity. The object of this study was to determine the effect of dose (500-3,000 μmoles/kg) on the disposition of dermally applied 14 C-labeled GEs by male F344 rats. Following application of [ 14 C]GEs in acetone (90 μL), the rats were immediately placed in metabolism cages for collection of excreta and exhaled air. No significant dose related trends in absorption (16-38% of applied dose) or disposition of 14 C were noted for any of the GEs. As the chain length of the GE increased, more of the dose was excreted in the urine as the alkoxy acetic acid (AA) and less of the dose entered the one carbon pool following dealkylation, as reflected by 14 C 2 exhaled. AA was the major metabolite of all 3 GEs except for ME at high doses where an unidentified metabolite represented 53% of the urinary metabolites. Ethylene glycol (EG) represented about 10-15% of the urinary metabolites for all 3 GEs at all doses. GEs administered in drinking water were metabolized more to EG and CO 2 , and less to AA in comparison to dermal studies, most likely due to the slower dose rate in drinking water studies

  20. 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.

  1. Rapid increase in cosmogenic 14C in AD 775 measured in New Zealand kauri trees indicates short-lived increase in 14C production spanning both hemispheres

    Science.gov (United States)

    Güttler, D.; Adolphi, F.; Beer, J.; Bleicher, N.; Boswijk, G.; Christl, M.; Hogg, A.; Palmer, J.; Vockenhuber, C.; Wacker, L.; Wunder, J.

    2015-02-01

    In 2012, Miyake et al. reported a sudden and strong increase of the atmospheric radiocarbon (14C) content in Japanese cedar trees of 1.2% between AD 774 and 775. While their findings were quickly confirmed by a German oak chronology for the Northern Hemisphere (NH), the question remained if the effect was seen in both hemispheres. Here we present the first annually resolved Southern Hemisphere (SH) 14C record spanning the interval AD 760-787, using New Zealand kauri (Agathis australis) chronology wood. An almost identical distinct increase compared to Northern Hemisphere data was observed, suggesting a cosmic event with globally uniform impact as a potential cause for the increase. Deploying a carbon cycle box model a worldwide averaged net 14C production of 2.2 ×108 14C atoms cm-2 was estimated, which is 3.7 times higher than the average annual 14C production. The immediate appearance of the event in tree rings on both hemispheres suggests a short duration event of significantly less than 1 yr.

  2. Studies on dissipation and degradation of 14 C-DDT and 14 C-parathion in egyptian soil under field conditions

    International Nuclear Information System (INIS)

    Ezz El-Arab, A.; Mostafa, I.Y.

    1991-01-01

    The rates of dissipation and degradation of the insecticides DDT and parathion were studied under field conditionsm using 14 C-labelled chemicals. Over a period of 12 weeks, extractable, soil-bound and total 14 C-activity were recorded. In case of DDT, dissipation of 14 C-activity from soil showed a continuous and gradual increase reaching about 30% after 8 weeks and remained constant up to 12 weeks. The formation of DDE as a principal metabolite seems to be increasing with time ans accounted for approximately 25% of the extractable residues after 12 weeks. There was also a gradual significant increase in the formation of soil 14 C-bound residues which reached 12% of the total residues after the same period. On the other hand, parathion dissipation from the soil under the same conditions did not exceed 10% up to 12 weeks. The amount of 14 C-bound residues was found to contribute 33% of the applied dose. Analysis of the extractable fraction revealed that parathion was partly degraded by soil microorganisms into p-amino phenol, p-nitrophenol, paraoxon, amino parathion and aminoparaoxon in different percentages depending on the depth of soil. 2 fig.,1 tab

  3. Retinal sensitivity and choroidal thickness in high myopia.

    Science.gov (United States)

    Zaben, Ahmad; Zapata, Miguel Á; Garcia-Arumi, Jose

    2015-03-01

    To estimate the association between choroidal thickness in the macular area and retinal sensitivity in eyes with high myopia. This investigation was a transversal study of patients with high myopia, all of whom had their retinal sensitivity measured with macular integrity assessment microperimetry. The choroidal thicknesses in the macular area were then measured by optical coherence tomography, and statistical correlations between their functionality and the anatomical structuralism, as assessed by both types of measurements, were analyzed. Ninety-six eyes from 77 patients with high myopia were studied. The patients had a mean age ± standard deviation of 38.9 ± 13.2 years, with spherical equivalent values ranging from -6.00 diopter to -20.00 diopter (8.74 ± 2.73 diopter). The mean central choroidal thickness was 159.00 ± 50.57. The mean choroidal thickness was directly correlated with sensitivity (r = 0.306; P = 0.004) and visual acuity but indirectly correlated with the spherical equivalent values and patient age. The mean sensitivity was not significantly correlated with the macular foveal thickness (r = -0.174; P = 0.101) or with the overall macular thickness (r = 0.103; P = 0.334); furthermore, the mean sensitivity was significantly correlated with visual acuity (r = 0.431; P < 0.001) and the spherical equivalent values (r = -0.306; P = 0.003). Retinal sensitivity in highly myopic eyes is directly correlated with choroidal thickness and does not seem to be associated with retinal thickness. Thus, in patients with high myopia, accurate measurements of choroidal thickness may provide more accurate information about this pathologic condition because choroidal thickness correlates to a greater degree with the functional parameters, patient age, and spherical equivalent values.

  4. Rapid analysis method for the determination of 14C specific activity in irradiated graphite.

    Directory of Open Access Journals (Sweden)

    Vidmantas Remeikis

    Full Text Available 14C is one of the limiting radionuclides used in the categorization of radioactive graphite waste; this categorization is crucial in selecting the appropriate graphite treatment/disposal method. We propose a rapid analysis method for 14C specific activity determination in small graphite samples in the 1-100 μg range. The method applies an oxidation procedure to the sample, which extracts 14C from the different carbonaceous matrices in a controlled manner. Because this method enables fast online measurement and 14C specific activity evaluation, it can be especially useful for characterizing 14C in irradiated graphite when dismantling graphite moderator and reflector parts, or when sorting radioactive graphite waste from decommissioned nuclear power plants. The proposed rapid method is based on graphite combustion and the subsequent measurement of both CO2 and 14C, using a commercial elemental analyser and the semiconductor detector, respectively. The method was verified using the liquid scintillation counting (LSC technique. The uncertainty of this rapid method is within the acceptable range for radioactive waste characterization purposes. The 14C specific activity determination procedure proposed in this study takes approximately ten minutes, comparing favorably to the more complicated and time consuming LSC method. This method can be potentially used to radiologically characterize radioactive waste or used in biomedical applications when dealing with the specific activity determination of 14C in the sample.

  5. Rapid analysis method for the determination of 14C specific activity in irradiated graphite.

    Science.gov (United States)

    Remeikis, Vidmantas; Lagzdina, Elena; Garbaras, Andrius; Gudelis, Arūnas; Garankin, Jevgenij; Plukienė, Rita; Juodis, Laurynas; Duškesas, Grigorijus; Lingis, Danielius; Abdulajev, Vladimir; Plukis, Artūras

    2018-01-01

    14C is one of the limiting radionuclides used in the categorization of radioactive graphite waste; this categorization is crucial in selecting the appropriate graphite treatment/disposal method. We propose a rapid analysis method for 14C specific activity determination in small graphite samples in the 1-100 μg range. The method applies an oxidation procedure to the sample, which extracts 14C from the different carbonaceous matrices in a controlled manner. Because this method enables fast online measurement and 14C specific activity evaluation, it can be especially useful for characterizing 14C in irradiated graphite when dismantling graphite moderator and reflector parts, or when sorting radioactive graphite waste from decommissioned nuclear power plants. The proposed rapid method is based on graphite combustion and the subsequent measurement of both CO2 and 14C, using a commercial elemental analyser and the semiconductor detector, respectively. The method was verified using the liquid scintillation counting (LSC) technique. The uncertainty of this rapid method is within the acceptable range for radioactive waste characterization purposes. The 14C specific activity determination procedure proposed in this study takes approximately ten minutes, comparing favorably to the more complicated and time consuming LSC method. This method can be potentially used to radiologically characterize radioactive waste or used in biomedical applications when dealing with the specific activity determination of 14C in the sample.

  6. Pesticides labelled with 14C. Pt. 4: Synthesis of Diuron and Linuron in various positions

    International Nuclear Information System (INIS)

    Volford, J.; Koltai, E.; Kling, F.; Volford, A.

    1996-01-01

    Diuron and Linuron, two herbicides, with very similar structures were labelled in their aromatic ring with 14 C. The yields of the synthesis (starting from Ba 14 CO 3 ) was 8.5% and 4.8%, respectively. Linuron was also labelled with 14 C in its urea group with 33% yield. (author)

  7. The effect of acetylcholine on 14C-assimilates translocation of Isatis tinctoria L

    International Nuclear Information System (INIS)

    Yang Chongjun; Tang Feiyu; Zhang Ping; Guo Yuhai

    2004-01-01

    The effects of acetylcholine on 14 C-assimilates translocation are studied with source-channel-sink of Isatis tinctoria L. The experiments show that 0.01 mmol/L treatments of acetylcholine on the phloem, can improve the output of 14 C-assimilates in leaves indicating that acetylcholine enhances the activity of phloem transport. (authors)

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  9. Benzene Synthesis for 14C Measurements and Evaluation of Uncertainty in Mollusk Shells

    International Nuclear Information System (INIS)

    Romero del Hombrebueno, B.; Simon, M. A.; Larena, P.

    2002-01-01

    This work describes the method and Instrumentation used by Environmental Isotopes laboratory of the CIEMAT Analytical Chemistry Laboratory (DIAE) for the synthesis of benzene from carbonates of mollusk shells and the liquid scintillation counting of 14 C for radiocarbon dating in these samples. The usefulness of mollusk shells for 14 C dating are considered. (Author) 15 refs

  10. Systemic translocation and metabolism of 14C-metalaxyl in citrus

    International Nuclear Information System (INIS)

    Musumeci, M.R.; Ruegg, E.F.

    1984-01-01

    Systemic uptake and translocation of 14 C-metalaxyl to citrus seedlings from soils (Humic Gley and Yellow Red Latosol) with different physical - chemical properties are studied. Seedlings of Citrus limonia are treated with 14 C-metalaxyl. (M.A.C.) [pt

  11. Study on the degradation of 14C maneb during the fabrication of concentrated tomato

    International Nuclear Information System (INIS)

    Sennaoui, Z.; Meguenni, H.; Bennaceur, M.

    1992-11-01

    Tomatoes were contaminated with 14C maneb to know the degradation of this fungicide during the technological process of tomato under laboratory conditions. 57,2% of the initial amount of 14C maneb applied was found in the many metabolites ETM, ETU and EU, were found during the technological transformation of tomato

  12. Extraction and analysis of 14C-carbofuran radioactivity in soil sample

    International Nuclear Information System (INIS)

    Maizatul Akmam Mhd Nasir; Nashriyah Mat

    2005-01-01

    Carbofuran insecticide or nematicide sprayed onto soil in the agroecosystem will be taken up by plant. Carbofuran residue will pollute the environment and organisms in the food chain. Extraction and analysis of 14 C-carbofuran in soil from lysimeter were carried out. The Liquid Scintillation Counter (LSC) was used to measure radioactivity of 14 C-carbofuran in soil sample. (Author)

  13. Concentration and distribution of 14C in aquatic environment around Qinshan nuclear power plant

    International Nuclear Information System (INIS)

    Wang Zhongtang; Guo Qiuju; Hu Dan; Xu Hong

    2015-01-01

    In order to study the concentration and distribution of 14 C in aquatic environment in the vicinity of Qinshan Nuclear Power Plant (NPP) after twenty years' operation, an apparatus extracting dissolved inorganic carbon from water was set up and applied to pretreat the water samples collected around Qinshan NPP. The 14 C concentration was measured by accelerator mass spectrometer (AMS). The results show that the 14 C specific activities in surface seawater samples range from 196.8 to 206.5 Bq/kg 203.4 ± 5.6) Bq/kg in average), which are close to the background. The 14 C concentrations in cooling water discharged from Qinshan NPP are close to the 14 C values in near shore seawater samples out of liquid radioactive effluent discharge period. It can be further concluded that the 14 C discharged previously is diluted and diffused well, and no 14 C enrichment in seawater is found. Also, no obvious increment in the 14 C specific activities of surface water and underground water samples are found between Qinshan NPP region and the reference region. (authors)

  14. BH3105 type neutron dose equivalent meter of high sensitivity

    International Nuclear Information System (INIS)

    Ji Changsong; Zhang Enshan; Yang Jianfeng; Zhang Hong; Huang Jiling

    1995-10-01

    It is noted that to design a neutron dose meter of high sensitivity is almost impossible in the frame of traditional designing principle--'absorption net principle'. Based on a newly proposed principle of obtaining neutron dose equi-biological effect adjustment--' absorption stick principle', a brand-new neutron dose-equivalent meter with high neutron sensitivity BH3105 has been developed. Its sensitivity reaches 10 cps/(μSv·h -1 ), which is 18∼40 times higher than one of foreign products of the same kind and is 10 4 times higher than that of domestic FJ342 neutron rem-meter. BH3105 has a measurement range from 0.1μSv/h to 1 Sv/h which is 1 or 2 orders wider than that of the other's. It has the advanced properties of gamma-resistance, energy response, orientation, etc. (6 tabs., 5 figs.)

  15. A high sensitivity nanomaterial based SAW humidity sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, T-T; Chou, T-H [Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Y-Y [Department of Mechanical Engineering, Tatung University, Taipei 104, Taiwan (China)], E-mail: wutt@ndt.iam.ntu.edu.tw

    2008-04-21

    In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128{sup 0}YX-LiNbO{sub 3} based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.

  16. Performance of terahertz metamaterials as high-sensitivity sensor

    Science.gov (United States)

    He, Yanan; Zhang, Bo; Shen, Jingling

    2017-09-01

    A high-sensitivity sensor based on the resonant transmission characteristics of terahertz (THz) metamaterials was investigated, with the proposal and fabrication of rectangular bar arrays of THz metamaterials exhibiting a period of 180 μm on a 25 μm thick flexible polyimide. Varying the size of the metamaterial structure revealed that the length of the rectangular unit modulated the resonant frequency, which was verified by both experiment and simulation. The sensing characteristics upon varying the surrounding media in the sample were tested by simulation and experiment. Changing the surrounding medium from that of air to that of alcohol or oil produced resonant frequency redshifts of 80 GHz or 150 GHz, respectively, which indicates that the sensor possessed a high sensitivity of 667 GHz per unit of refractive index. Finally, the influence of the sample substrate thickness on the sensor sensitivity was investigated by simulation. It may be a reference for future sensor design.

  17. Limitations in the use of 14C-glycocholate breath and stool bile acid determinations in patients with chronic diarrhea

    International Nuclear Information System (INIS)

    Ferguson, J.; Walker, K.; Thomson, A.B.

    1986-01-01

    Analysis of a modified 14 C-glycocholate breath test on 165 consecutive in-patients being investigated for chronic diarrhea showed that the measurement of 14 CO 2 between 3 and 6 h after oral dosing of 5 microCi of 14 C-glycocholic acid was of only limited use to distinguish between patients with Crohn's disease (CD), idiopathic bile salt wastage (IBW), or ileal resection (IR) from those with the irritable bowel syndrome (IBS). Continuing 14 CO 2 collections for up to 24 h was of little more help in establishing the presence of bacterial overgrowth syndrome (BOS) and in distinguishing between BOS and CD. Stool bile acid measurements were of use in differentiating between IBW and IBS, but did not distinguish between CD and BOS or between CD and IR. Since the range of normal values was defined by measurements in the IBS group, a positive test was specific for an organic cause of chronic diarrhea. Even so, the sensitivity of the test was relatively low: CD, 53%; IR, 23%; IBW, 14 %; and BOS, 10%. We believe that the 24-h 14 C-glycocholic breath test combined with the measurement of stool bile acids represents a screening test of only limited use for the identification of organic causes of chronic diarrhea

  18. Development of a nanofiltration method for bone collagen {sup 14}C AMS dating

    Energy Technology Data Exchange (ETDEWEB)

    Boudin, Mathieu, E-mail: mathieu.boudin@ugent.be [Royal Institute for Cultural Heritage, Jubelpark 1, B-1000 Brussels (Belgium); Ghent University, Faculty of Bioscience Engineering, Laboratory of Applied Physical Chemistry, Coupure Links 653, B-9000 Ghent (Belgium); Boeckx, Pascal [Ghent University, Faculty of Bioscience Engineering, Laboratory of Applied Physical Chemistry, Coupure Links 653, B-9000 Ghent (Belgium); Buekenhoudt, Anita [Flemish Institute for Technological Research, Separation and Conversion Technology, Boeretang 200, B-2400 Mol (Belgium); Vandenabeele, Peter [Ghent University, Department of Archaeology, Sint-Pietersnieuwstraat 35, B-9000 Ghent (Belgium); Van Strydonck, Mark [Royal Institute for Cultural Heritage, Jubelpark 1, B-1000 Brussels (Belgium)

    2013-01-15

    Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased {sup 14}C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) {approx}100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used. In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate. Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. {sup 14}C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant

  19. Diurnal productivity and apparent 14C-calcification in the staghorn coral, Acropora acuminata

    International Nuclear Information System (INIS)

    Barnes, D.J.; Crossland, C.J.

    1978-01-01

    The rate of 14 C-fixation by Acropora acuminata tissues showed a marked increase after dawn. However, maximum 14 C-fixation was not achieved until early afternoon. The apparent 14 C-incorporation rate into the skeleton of whole branches reached a peak around noon. However, the major period of 14 C-deposition occurred from noon to mid-afternoon. The broad peak of 14 C-incorporation into skeleton of whole branches reflects two rate maxima; a late-morning maximum of zooxanthellae-free terminal calices, probably related to translocation of fixed carbon from basal tissues; and an early afternoon maximum for the zooxanthellae-containing basal areas of branches. (author)

  20. Correlation of [14C]muscimol concentration in rat brain with anticonvulsant activity

    International Nuclear Information System (INIS)

    Matthews, W.D.; Intoccia, A.P.; Osborne, V.L.; McCafferty, G.P.

    1981-01-01

    Muscimol, an in vivo and in vitro GABA agonist, has anticonvulsant activity against bicuculline-induced seizures when given systemically to rats. To determine whether parent compound or a metabolite possessed the anticonvulsant activity, experiments were performed with [ 14 C]muscimol. Anticonvulsant activity was determined by the percent of animals protected against tonic forelimb extension induced by bicuculline. Brain and urine were analyzed for unchanged [ 14 C]muscimol by thin-layer chromatography. The time course of anticonvulsant activity and [ 14 C]muscimol concentration in brain after intravenous injection were similar. Peak brain concentration of [ 14 C]muscimol and maximal protection against bicuculline-induced seizures occurred simultaneously. These data suggest that intravenously administered [ 14 C]muscimol rapidly penetrates brain tissue and parent compound is responsible for antagonism of bicuculline-induced convulsions. (Auth.)

  1. Bound residues in corn plants treated with 14C-atrazine and bioavailability to rats

    International Nuclear Information System (INIS)

    Khan, S.U.

    1986-01-01

    Corn plants, about 3.5 months old and treated with 14 C-atrazine, were used in an experiment in which the aerial portion of the plants was exhaustively extracted with solvents. The extracted dried material containing bound 14 C-residues was fed to rats. The extracted aerial portion of control corn plants fortified with 14 C-atrazine was also fed to rats. After four days, 88% and 32% of the radioactivity was excreted in the faeces, and 10% and 60% radioactivity was voided in the urine from rats fed plant material containing bound and fortified 14 C-residues, respectively. The data suggest that the bioavailability to rats of bound 14 C-residues in corn material is low. (author)

  2. Working out microsyntheses for different chlorinated biphenyls and preparation of 2,2'-dichlorobiphenyl-14C and 2,4'-dichlorobiphenyl-14C

    International Nuclear Information System (INIS)

    Geuenich, H.H.

    1972-01-01

    The microsyntheses for the preparation of chlorated biphenyls starting with benzene were worked out. 2,2'-dichlorobiphenyl- 14 C and 2,4'-dichlorobiphenyl- 14 C were prepared. 42 mCi benzene- 14 C were converted into nitrobenzene with nitrating acid, which was reduced to aniline by tin(II) chloride/hydrochloric acid. Following the acetylation of aniline with acetic anhydride, it was monochlorated in glacial acetic acid with chloride of lime, and the chlorination mixture was chromatographically separated in columns. 5.8 mCi o'-chloroanaline were diazotized and converted in ammoniacal copper(I) salt solution. 2 μCi 2,2'-dichlorobiphenyl were obtained. (orig./LH) [de

  3. Incorporation of U-/sup 14/C-glucose into the lipids U-/sup 14/C and sugars of Culex pipiens fatigans

    Energy Technology Data Exchange (ETDEWEB)

    Duggal, Rita Nanda; Subrahmanyam, D

    1983-11-01

    The role of U-/sup 14/C-glucose as a lipogenic precursor was examined in larvae and adults of C. pipiens fatigans. The pattern of incorporation of the radiocarbon was also examined in the sugars of these insects. It was found that on feeding of larvae and adults with /sup 14/C-glucose, the phospholipid fraction of the insects was associated with more than 70 per cent of the total lipid radiolabel. However, the percentage distribution of the phospholipid label in the different phospholipid fractions of the larvae and adults was different. Among the neutral lipids, a low but significant label in cholesterol was of considerable interest. The /sup 14/C-glucose was also converted to trehalose in both larvae and adults. However, the two stages differed in the utilization of glucose and trehalose. 5 figures, 16 refs.

  4. Vegetation stability in the Southeastern Brazilian coastal area from 5500 to 1400 14C yr BP deduced from charcoal analysis.

    Science.gov (United States)

    Scheel-Ybert

    2000-06-01

    Charcoal analysis of six shell mounds showed that no major changes of the mainland vegetation ecosystem have taken place along the southeastern Brazilian coast (22 degrees 53'-22 degrees 57'S, 42 degrees 03'-42 degrees 33'W) from 5500 to 1400 14C yr BP. These shell mounds have been occupied by sedentary fisher-gatherer-hunters. Charcoal fragments retrieved from vertical profiles in the archaeological sites were examined; taxonomic determinations were based on a reference collection of charred woods and a program for computer-aided identification. Charcoal assemblages of all the studied sites present taxa from various restinga vegetation types, mangroves, xeromorphic coastal forest, and inland Atlantic Forest. The restinga ecosystem, characteristic of the Brazilian coast, is associated with sandy beach ridges; the restinga forest was much more abundant during the studied period than nowadays. The charcoal assemblages represent mainly the local vegetation; a regional reconstruction depends on the study of numerous sites. In the Cabo Frio region, open restinga taxa are more abundant in the Sambaqui do Forte, while forest elements are more important in the Sambaquis Salinas Peroano and Boca da Barra. The sites studied in the Arraial do Cabo (Sambaqui da Ponta da Cabeça) and in the Saquarema regions (Sambaquis da Pontinha and da Beirada) show that open restinga formations were locally predominant. A comparison of multivariate analysis applied to both charcoal assemblages and to phytosociological data of the extant vegetation showed a good correspondence between the charcoal spectra and the present vegetation. The high taxonomic diversity of archaeological charcoal samples and numerous fragments showing traces of decay before charring suggests that aleatory gathering of dead wood constituted the main source of firewood for fisher-gatherer-hunters populations. Condalia sp. was probably selected for cultural reasons.The only significant fluctuations on the charcoal

  5. Appearance of circulating and tissue 14C-lipids after oral 14C-tripalmitate administration in the late pregnant rat

    International Nuclear Information System (INIS)

    Argiles, J.; Herrera, E.

    1989-01-01

    Studies were performed to determine whether and/or how dietary lipids participate in maternal hypertriglyceridemia during late gestation in the rat. After oral administration of glycerol-tri(1-14C)-palmitate, total radioactivity in plasma increased more rapidly in 20-day pregnant rats than in either 19-day pregnant rats or virgin controls. At the peak of plasma radioactivity, four hours after the tracer was administered, most of the plasma label corresponded to 14C-lipids in triglyceride-rich lipoproteins (d less than 1.006), and when expressed per micromol of triglyceride, values were higher in pregnant than in virgin rats. The difference was less after 24 hours, although at this time the level of 14C-lipids in d less than 1.006 lipoproteins was still higher in 20-day pregnant rats than in virgins. Tissue 14C-lipids, as expressed per gram of fresh weight, were similar in pregnant and virgin rats, but the values in mammary glands were much higher in the former group. Estimated recovery of administered radioactivity four hours after tracer in total white adipose tissue, mammary glands, and plasma lipids was higher in pregnant than in virgin rats. No difference was found between 20-day pregnant and virgin rats either in the label retained in the gastrointestinal tract or in that exhaled as 14C-CO2 during the first four hours following oral administration of 14C-tripalmitate. These findings plus the known maternal hyperphagia, indicate that in the rat at late pregnancy triglyceride intestinal absorption is unchanged or even enhanced and that dietary lipids actively contribute to both maternal hypertriglyceridemia and lipid uptake by the mammary gland

  6. Sensitive high performance liquid chromatographic method for the ...

    African Journals Online (AJOL)

    A new simple, sensitive, cost-effective and reproducible high performance liquid chromatographic (HPLC) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 4-chlorophenylbiguanide (4-CPB) in urine and plasma is described. The extraction procedure is a simple three-step process ...

  7. Methylation-Sensitive High Resolution Melting (MS-HRM).

    Science.gov (United States)

    Hussmann, Dianna; Hansen, Lise Lotte

    2018-01-01

    Methylation-Sensitive High Resolution Melting (MS-HRM) is an in-tube, PCR-based method to detect methylation levels at specific loci of interest. A unique primer design facilitates a high sensitivity of the assays enabling detection of down to 0.1-1% methylated alleles in an unmethylated background.Primers for MS-HRM assays are designed to be complementary to the methylated allele, and a specific annealing temperature enables these primers to anneal both to the methylated and the unmethylated alleles thereby increasing the sensitivity of the assays. Bisulfite treatment of the DNA prior to performing MS-HRM ensures a different base composition between methylated and unmethylated DNA, which is used to separate the resulting amplicons by high resolution melting.The high sensitivity of MS-HRM has proven useful for detecting cancer biomarkers in a noninvasive manner in urine from bladder cancer patients, in stool from colorectal cancer patients, and in buccal mucosa from breast cancer patients. MS-HRM is a fast method to diagnose imprinted diseases and to clinically validate results from whole-epigenome studies. The ability to detect few copies of methylated DNA makes MS-HRM a key player in the quest for establishing links between environmental exposure, epigenetic changes, and disease.

  8. Aluminum nano-cantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

  9. High sensitivity probe absorption technique for time-of-flight ...

    Indian Academy of Sciences (India)

    Abstract. We report on a phase-sensitive probe absorption technique with high sen- sitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms.

  10. Intra cellular distribution of 8-14C-puromycin aminonucleoside in ultraviolet irradiated Escherichia coli

    International Nuclear Information System (INIS)

    Sideropoulos, A.S.

    1976-01-01

    The uptake of 8- 14 C-puromycin aminonucleoside (8- 14 C-PAN) was studied in ultraviolet (UV) irradiated strains of E. coli B/r hcr + and hcr - . The cells took up only 0.1-0.3% of the 8- 14 C-PAN present in the medium when grown in minimal (M9) containing 8- 14 C-PAN. When ethylenedinitrilotetra-acetic acid (EDTA) treated E. coli cells are placed in a medium containing 8- 14 C-PAN, the total concentration of 8- 14 C-PAN in the cell reaches 43-54% of the medium within 30 min of incubation. Almost all 8- 14 C-PAN can be dialyzed from cells exposed in the absence of an energy source, but cells metabolizing in M9 medium during exposure can retain up to 30% of their internal concentration. Bacteria grown in the presence of 8- 14 C-PAN, accumulated the radioactive material intracellulary in three forms, namely, unbound, reversibly bound (dialyzable) and irreversibly bound to the protein (nondialyzable). Approx. 70-77% of the irreversibly bound radioactive material linked with the protein fraction was released by treatment with a protease. Addition of PAN into the post-irradiation medium of EDTA-treated hcr + cells, increased UC induced mutation rates. Antimutagenic purine ribosides decreased the final level of 8- 14 C-PAN accumulated by the cells. Decreases in 8- 14 C-PAN uptake in the presence of antimutagens correspond to reductions in the rate of mutation to streptomycin resistance induced by UV light. Therefore, protein bound PAN appears to be the relevant component in the enhancement of UV induced mutation by this drug

  11. On the identification of carbonaceous aerosols via 14C accelerator mass spectrometry, and laser microprobe mass spectrometry

    International Nuclear Information System (INIS)

    Currie, L.A.; Fletcher, R.A.; Klouda, G.A.

    1987-01-01

    Carbon isotopic measurements ( 12 C, 14 C), derived from chemical measurements of total carbon plus AMS measurements of 14 C/ 12 C have become an accepted means for estimating fossil and contemporary carbon source contributions to atmospheric carbon. Because of the limited sensitivity of these techniques, however, such measurements are restricted to 'bulk' samples comprising at least 10-100 μg of carbon. Laser microprobe mass spectrometry (LMMS) offers an important complementary opportunity to investigate the chemical nature of individual particles as small as 0.1 μm in diameter. Although there is little hope to measure 14 C/ 12 C in such small samples, the compositional and structural information available with the laser microprobe is of interest for possible source discrimination. Also, the analysis of individual particles, which may reflect individual sources, yields significant potential increases in spatial, temporal and source resolution, in comparison to bulk sample analysis. Results of our exploratory investigation of known sources of carbonaceous particles, using LMMS, are presented. By applying multivariate techniques to laser mass spectra of soot from the combustion of heptane and wood, we found striking differences in the alkali metals (notably potassium) in the positive ion mass spectra. For ambient particles, 14 C has proved to be a crucial adjunct for the development and validation of the LMMS approach to single particle source assignment via carbon cluster pattern recognition. The combined techniques offer great promise for objective modeling (number and types of carbon sources) and for extension of the dichotomous carbon apportionment (fossil, contemporary) to subclasses such as soot from wood and agricultural burning, and that from coal and petroleum combustion. (orig.)

  12. Determination of the hydrothermal degradation products of D-(U-14C) glucose and D-(U-14C) fructose by TLC

    International Nuclear Information System (INIS)

    Bonn, G.; Bobleter, O.

    1983-01-01

    Hydrothermal degradation was examined using D-(U- 14 C) glucose and D-(U- 14 C) fructose. By thin layer chromatography with methylene chloride, tetrahydrofuran (THF), acetic acid - 60:20:20 as a mobile phase; it was possible to separate and identify the carbohydrates and their reaction products, glyceraldehyde, dihydroxyacetone, methylglyoxal, glycolaldehyde, 5-hydroxymethylfurfural and furfural. Up to 99% of the initial activity was determined by scintillation counting of the TL-chromatograms. A reaction scheme for the hydrothermal degradation of glucose and fructose was obtained from these results. (author)

  13. Effects of fertilizers, fungicides and herbicides on the fate of 14C-parathion and 14C-fonofos in soils and crops

    International Nuclear Information System (INIS)

    Lichtenstein, E.P.; Ferris, I.; Liang, T.T.; Koeppe, M.

    1983-01-01

    The fate of 14 C-parathion and 14 C-fonofos in soil is significantly affected by the presence of organic and inorganic fertilizers, fungicides and herbicides, possibly via the effect of soil microflora. Soil microorganisms are responsible for the oxidative as well as the reductive degradation of the insecticide. Using 14 carbon, the authors studied the effects of selected fungicides (benlate, captafol and manzate) herbicides (2,4-D parathion) and fertilizers ((NH 4 ) 6 SO 4 , KNO 3 , urea) on pesticides in Cromberry soils. Results of the study stress the importance of investigating the environmental fate of a particular pesticide in relation to the presence of the agricultural chemicals

  14. Preparation of 2-(. alpha. -(2-ethoxyphenoxy)benzyl)-(5- sup 14 C)morpholine methanesulfonate (( sup 14 C)reboxetine):a new antidepressant agent

    Energy Technology Data Exchange (ETDEWEB)

    Angiuli, P.; Fontana, E.; Vicario, G.P. (Farmitalia Carlo Erba s.r.l., Milan (Italy))

    1991-05-01

    The labelling with radiocarbon of the new antidepressant agent Reboxetine is described. The preparation has been carried out in a two step procedure using 2-chloro-N-(3-(2-ethoxyphenoxy)-2-hydroxy-3-phenyl)propyl-(1-{sup 14}C)acetamide as starting material. The expected compound was prepared by cyclization of the above halogenoacylamido alcohol to the corresponding morpholone ring followed by reduction to the final (5-{sup 14}C)morpholine derivative 4, 98% radiochemically pure and with specific radioactivity of 988 MBq/mmol. An overall radiochemical yield of 57.5% was achieved. (author).

  15. 14CO2 fixation and allocation of 14C into major biochemical fractions in different parts of Indian mustard (Brassica juncea)

    International Nuclear Information System (INIS)

    Subrahmanyam, D.; Rathore, V.S.

    1993-01-01

    14CO2 fixation and transport of 14C-photosynthates amongst different parts of Indian mustard (Brassica juncea) and the incorporation of 14C into major chemical fractions in different plant parts was studied at ripening stage. Stem and pod together contributed 70 % of the total 14C fixed by the plant. In all plant parts neutral saccharide fraction contained maximum radioactivity immediately after exposing plants to 14CO2. After 24 h, the radioactivity in this fraction declined considerably due to translocation or conversion into other fractions. Concomitantly radioactivity in lipids and pigments, residue and starch fractions increased after 24 h. The 14C allocation patterns in stem and leaves were similar. However, in pods very high radioactivity was recovered from amino and organic acid fractions indicating the presence of active phosphoenolpyruvate carboxylase in pod walls

  16. Semi-synthetic preparation of 1-O-[1'-14C]hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (platelet activating factor) using plant cell cultures

    International Nuclear Information System (INIS)

    Weber, N.; Mangold, H.K.

    1985-01-01

    Incubation of photomixotrophic cell suspension cultures of rape (Brassica napus) and heterotrop