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Sample records for c-13 isotopic studies

  1. Yield and enrichment studies of C-13 isotope by multi-photon ...

    Indian Academy of Sciences (India)

    Abstract. Multi-photon dissociation of Freon-22 (CF2HCl) at low temperatures has been carried out to separate the C-13 isotope using a TEA CO2 laser. Yield and enrichment of C-13 isotope in the product C2F4 are studied at 9P(22) laser line as a function of temperature (–50°C to 30°C). It is observed that at a given fluence ...

  2. C-13 isotopic studies of the surface catalysed reactions of methane

    International Nuclear Information System (INIS)

    Long, M.A.; He, S.J.X.; Adebajo, M.

    1997-01-01

    The ability of methane to methylate aromatic compounds, which are considered to be models for coal, is being studied. Related to this reaction, but at higher temperatures, is the direct formation of benzene from methane in the presence of these catalysts. Controversy exists in the literature on the former reaction, and 13 C isotope studies are being used to resolve the question. The interest in this reaction arises because the utilisation of methane, in the form of natural gas, in place of hydrogen for direct coal liquefaction would have major economic advantage. For this reason Isotope studies in this area have contributed significantly to an understanding of the methylation reactions. The paper describes experiments utilising methane 13 C, which show that methylation of aromatics such as naphthalene by the methane 13 C is catalysed by microporous, Cu-exchanged SAPO-5, at elevated pressures (6.8 MPa) and temperatures around 400 degree C. The mass spectrometric analysis and n.m.r. study of the isotopic composition of the products of the methylation reaction demonstrate unequivocally that methane provides the additional carbon atom for the methylated products. Thermodynamic calculations predict that the reaction is favourable at high methane pressures under these experimental conditions. The mechanism as suggested by the isotope study is discussed. The catalysts which show activity for the activation of methane for direct methylation of organic compounds, such as naphthalene, toluene, phenol and pyrene, are substituted aluminophosphate molecular sieves, EIAPO-5 (where El=Pb, Cu, Ni and Si) and a number of metal substituted zeolites. Our earlier tritium studies had shown that these catalysts will activate alkanes, at least as far as isotope hydrogen exchange reactions are concerned

  3. Selective conversion of plasma glucose into CO2 by Saccharomyces cerevisiae for the measurement of C-13 abundance by isotope ratio mass spectrometry : proof of principle

    NARCIS (Netherlands)

    Rembacz, Krzysztof P.; Faber, Klaas Nico; Stellaard, Frans

    2007-01-01

    To study carbohydrate digestion and glucose absorption, time-dependent C-13 enrichment in plasma glucose is measured after oral administration of naturally occurring C-13-enriched carbohydrates. The isotope enrichment of the administered carbohydrate is low (APE <0.1%) and plasma C-13 glucose

  4. The 12C/13C Isotopic Ratio in Planetary Nebulae as Deduced from IUE Data

    Science.gov (United States)

    Miskey, C. L.; Feibelman, W. A.; Bruhweiler, F. C.

    2000-05-01

    The relative abundances of C, N, and O and the isotopic ratio of 12C/13C represent tracers of nucleosynthesis in intermediate stars with main-sequence masses between 0.6 and 8.0 solar masses in our Galaxy. Determining these abundances and the isotopic 12C/13C ratio in planetary nebulae (PNe) represent perhaps the best means to discern exactly how the ISM is enriched by CNO stellar nucleosynthesis. Walsh et al. (1996) and Clegg et al. (1997), using the Hubble Space Telescope, have derived the isotopic 12C/13C abundance ratio in the galactic carbon-rich PN, NGC 3918, and placed marginal constraints on it for the Magellanic PNe, N2 (SMC) and N122 (LMC). This was done using the well-known 12C 3P-1S (J=1-0 and J=2-0) transitions of C+2 at 1906.68 Angstroms and 1908.77 Angstroms and a J=0-0 transition at 1909.6 Angstroms, which is strictly forbidden in 12C. The finite nuclear spin of 13C (I=1/2) permits a corresponding F=1/2-1/2 electric dipole transition not seen in 12C. Since the 1909.6 Angstroms line is well separated from the other two 12C transitions, it provides an important means of determining 12C/13C in planetary nebulae. We have just completed a search of archival International Ultraviolet Explorer (IUE) high-dispersion spectra of approximately three dozen PNe, and derived 12C/13C ratios of 39 and 23 for the galactic PNe, NGC 2440 and NGC 6302, respectively. These are values much lower than the solar value of 89. In the other objects, the limited S/N of the IUE data indicate 12C/13C ratio upper limits much higher than 50. The implications of these results and their pertinence to stellar evolution are discussed.

  5. Isotopically Enriched C-13 Diamond Anvil as a Stress Sensor in High Pressure Experiments

    Science.gov (United States)

    Vohra, Yogesh; Qiu, Wei; Kondratyev, Andreiy; Velisavljevic, Nenad; Baker, Paul

    2004-03-01

    The conventional high pressure diamond anvils were modified by growing an isotopically pure C-13 diamond layer by microwave plasma chemical vapor deposition using methane/hydrogen/oxygen chemistry. The isotopically pure C-13 nature of the culet of the diamond anvil was confirmed by the Raman spectroscopy measurements. This isotopically engineered diamond anvil was used against a natural abundance diamond anvil for high pressure experiments in a diamond anvil cell. Spatial resolved Raman spectroscopy was used to measure the stress induced shift in the C-13 layer as well as the undelying C-12 layer to ultra high pressures. The observed shift and splitiing of the diamond first order Raman spectrum was correlated with the stress distribution in the diamond anvil cell. The experimental results will be compared with the finite element modeling results using NIKE-2D software in order to create a mathematical relationship between sets of the following parameters: vertical (z axis) distance; horizontal (r axis) distance; max shear stress, and pressure. The isotopically enriched diamond anvils offer unique opportunities to measure stress distribution in the diamond anvil cell devices.

  6. The 12C/ 13C isotopic ratio in Titan hydrocarbons from Cassini/CIRS infrared spectra

    Science.gov (United States)

    Nixon, C. A.; Achterberg, R. K.; Vinatier, S.; Bézard, B.; Coustenis, A.; Irwin, P. G. J.; Teanby, N. A.; de Kok, R.; Romani, P. N.; Jennings, D. E.; Bjoraker, G. L.; Flasar, F. M.

    2008-06-01

    We have analyzed infrared spectra of Titan recorded by the Cassini Composite Infrared Spectrometer (CIRS) to measure the isotopic ratio 12C/ 13C in each of three chemical species in Titan's stratosphere: CH 4, C 2H 2 and C 2H 6. This is the first measurement of 12C/ 13C in any C 2 molecule on Titan, and the first measurement of 12CH 4/ 13CH 4 (non-deuterated) on Titan by remote sensing. Our spectra cover five widely-spaced latitudes, 65° S to 71° N and we have searched for both latitude variability of 12C/ 13C within a given species, and also for differences between the 12C/ 13C in the three gases. For CH 4 alone, we find C12/C13=76.6±2.7 (1- σ), essentially in agreement with the 12CH 4/ 13CH 4 measured by the Huygens Gas Chromatograph/Mass Spectrometer instrument (GCMS) [Niemann, H.B., and 17 colleagues, 2005. Nature 438, 779-784]: 82.3±1.0, and also with measured values in H 13CN and 13CH 3D by CIRS at lower precision [Bézard, B., Nixon, C., Kleiner, I., Jennings, D., 2007. Icarus 191, 397-400; Vinatier, S., Bézard, B., Nixon, C., 2007. Icarus 191, 712-721]. For the C 2 species, we find C12/C13=84.8±3.2 in C 2H 2 and 89.8±7.3 in C 2H 6, a possible trend of increasingly value with molecular mass, although these values are both compatible with the Huygens GCMS value to within error bars. There are no convincing trends in latitude. Combining all fifteen measurements, we obtain a value of C12/C13=80.8±2.0, also compatible with GCMS. Therefore, the evidence is mounting that 12C/ 13C is some 8% lower on Titan than on the Earth (88.9, inorganic standard), and lower than typical for the outer planets ( 88±7 [Sada, P.V., McCabe, G.H., Bjoraker, G.L., Jennings, D.E., Reuter, D.C., 1996. Astrophys. J. 472, 903-907]). There is no current model for this enrichment, and we discuss several mechanisms that may be at work.

  7. C-12/C-13 isotope ratio of the interstellar medium in the neighborhood of the sun

    International Nuclear Information System (INIS)

    Hawkins, I.; Jura, M.

    1987-01-01

    Data from observations of Xi Per, P Cyg, 20 Tau, and 23 Tau, obtained at 4232 and 3957 A using a coude spectrograph and a 1872-element reticon on the 3-m Shane telescope at Lick Observatory during 1984-1985, are combined with data on Zeta Oph (Hawkins et al., 1985) and used to estimate the C isotope ratio of the ISM near the sun. The results are presented in extensive tables and graphs and characterized in detail. The (C-12)H(+)/(C-13)H(+) abundance ratios toward the five stars are found to agree to within 12 percent and shown to be representative of the C-12/C-13 ratios in the gas, strongly indicating that the local ISM is homogeneous. The difference between the ISM ratio (43 + or - 4) and the solar-system value (89) is attributed to the chemical evolution of the ISM in the 4.9 Gyr since the formation of the sun. 78 references

  8. CO2 and 12C:13C Isotopic Ratios on Phoebe and Iapetus

    Science.gov (United States)

    Clark, R. N.; Brown, R. H.; Cruikshank, D. P.

    2016-12-01

    Cassini VIMS has obtained spatially resolved 0.35 to 5.1 micron reflectance spectra of Saturn's satellites beginning with the Phoebe fly-by in 2004 and a close fly-by of Iapetus in 2007. Both surfaces contain relatively abundant CO2. The new (2016 RC19) calibration of VIMS has provided a significant increase in the data quality, such that isotopic absorption bands in CO2 are now well defined. CO2 on Saturn's icy satellites is trapped (Cruikshank et al., 2010, Icarus v206 p561; Pinilla-Alonso et al. 2011, Icarus v211, p75i), predominantly in the dark material (Clark et al. 2012, Icarus v218 p831). Clark et al. modeled the CO2 abundance as 2.8% on Iapetus and 3.7% on Phoebe. The main 12CO2 band in VIMS spectra on Iapetus occurs at 4.253 microns and Phoebe at 4.266 microns. The 13CO2 absorption is strong on Phoebe at 4.367 microns and weak on Iapetus at 4.387 microns. Converting the Phoebe, Iapetus, and a lab reflectance spectrum (of trace H2O-CO2 mixture on a diffuse substrate), we derive preliminary values for the ratio of the equivalent widths of the 12C and 13C absorptions as 19±2 on Phoebe, 82±8 on Iapetus, and 98±10 for the laboratory spectrum. These ratios are related to the 12C/13C ratio, but there may be effects due to intra-molecular and inter-molecular coupling that will contribute to systematic errors in the isotopic abundances derived using equivalent-width measurements that we've yet to quantify. We Believe the effects are small, and will be attempting to quantify them in the future. For comparison, the terrestrial value of the 12C/13C ratio is 90.17, and vibrational coupling may explain the slightly high lab mixture result. The local interstellar medium is 69±15 (Boogert et al., 2000, A&A). Because the CO2 bands on Phoebe and Iapetus dark material have different positions, and because the observed 13C absorption strengths are so different, the surface evolutions must be different. The large enrichment in 13C on Phoebe argues for significant

  9. Medical Isotope Program: O-18, C-13, and Xe-129 Final Report CRADA No. TC-2043-02

    Energy Technology Data Exchange (ETDEWEB)

    Scheibner, K. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fought, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-27

    This was a collaborative effort between the University of California, Lawrence Livermore National Laboratory (LLNL) and Spectra Gases, Inc., to develop new and cheaper sources of Oxgyen-18 (O-18), Carbon-13 (C-13), and Xenon-129 (Xe-129), and to develop new applications of these stable medical isotopes in medicine resulting in a substantial increase in stable isotopes that are important to human health sciences.

  10. 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

  11. Determination of the isotopic (C-13/C-12) discrimination by terrestrial biology from a global network of observations

    International Nuclear Information System (INIS)

    Bakwin, P.S.; Tans, P.P.; White, J.W.C.; Andres, R.J.

    1998-01-01

    Data from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory global air sampling network are analysed in order to extract the signatures of isotopic (C-13/C-12) discrimination by the terrestrial iota and of fossil fuel combustion for the regions surrounding the sampling sites. Measurements of carbon monoxide (CO) are used to give an estimate of the contribution of fossil fuel combustion to the short-term variability of carbon dioxide. In general, variations of CO 2 are more strongly dominated by biological exchange, so the isotopic signature of fossil fuel combustion, while consistent with inventory estimates, is not well constrained by the observations. Conversely, results for isotope discrimination by the terrestrial biosphere are not strongly dependent on assumptions about fossil fuel combustion. The analysis appears valid primarily for stations fairly near continental source/sink regions, particularly for midlatitude regions of the northern hemisphere. For these stations a mean discrimination of -16.8 per mil (%) is derived, with site-to-site variability of 0.8% and with little or no consistent latitudinal gradient

  12. An isotope approach based on C-13 pulse-chase labelling vs. the root trenching method to separate heterotrophic and autotrophic respiration in cultivated peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Biasi, C.; Pitkamaki, A. S.; Tavi, N. M.; Koponen, H. T.; Martikainen, P. J. [Univ.of Eastern Finland, Kuopio (Finland). Dept. of Environmental Science], e-mail: christina.biasi@uef.fi

    2012-11-01

    We tested an isotope method based on C-13 pulse-chase labelling for determining the fractional contribution of soil microbial respiration to overall soil respiration in an organic soil (cutaway peatland, eastern Finland), cultivated with the bioenergy crop, reed canary grass. The plants were exposed to CO{sub 2}-13 for five hours and the label was thereafter determined in CO{sub 2} derived from the soil-root system. A two-pool isotope mixing model was used to separate sources of respiration. The isotopic approach showed that a minimum of 50% of the total CO{sub 2} originated from soil-microbial respiration. Even though the method uses undisturbed soil-plant systems, it has limitations concerning the experimental determination of the true isotopic signal of all components contributing to autotrophic respiration. A trenching experiment which was comparatively conducted resulted in a 71% fractional contribution of soil-microbial respiration. This value was likely overestimated. Further studies are needed to evaluate critically the output from these two partitioning approaches. (orig.)

  13. Diode laser absorption spectrometry for (CO2)-C-13/(CO2)-C-12 isotope ratio analysis : Investigation on precision and accuracy levels

    NARCIS (Netherlands)

    Castrillo, A; Casa, G; Kerstel, E; Gianfrani, L

    2005-01-01

    Near-infrared laser spectroscopy is used to measure the C-13/C-12 isotope abundance ratio in gas phase carbon dioxide. The spectrometer, developed expressly for field applications, is based on a 2 mu m distributed feedback diode laser in combination with sensitive wavelength modulation detection. It

  14. Determination of urea kinetics by isotope dilution with [C-13]urea and gas chromatography isotope ratio mass spectrometry (GC-IRMS) analysis

    NARCIS (Netherlands)

    Kloppenburg, Wybe; Wolthers, BG; Stellaard, F; Elzinga, H; Tepper, T; deJong, PE; Huisman, RM

    1. Stable urea isotopes can be used to study urea kinetics in humans, The use of stable urea isotopes far studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material, We devised a urea dilution for measurement of the distribution volume,

  15. Study for the charge symmetric systems, 12C+13N and 12C+13C with the orthogonalized coupled-reaction-channel method

    International Nuclear Information System (INIS)

    Imanishi, B.; Denisov, V.; Motobayashi, T.

    1996-10-01

    The charge-symmetric scattering systems, 12 C+ 13 N and 12 C+ 13 C have been investigated by using the orthogonalized coupled-reaction-channel (OCRC) method with the basis functions of the elastic, inelastic and transfer channels defined by the single-particle states, 1p1/2, 2s1/2, 1d5/2 and 1d3/2 of the valence nucleon in 13 N or 13 C. The data of the elastic scattering of 13 N on 12 C measured by Lienard et al. have been explained consistently with the data of the elastic and inelastic scattering of the 12 C+ 13 C system. The CRC effects both on the above systems are very strong, although those on the 12 C+ 13 N system are fairly weaker than the 12 C+ 13 C system. The role of the highly excited single-particle states 1d3/2 is particularly important in the formation of a specific CRC scheme, i.e., the formation of the covalent molecules due to the hybridization caused by the mixing of the different parity single-particle states. The fusion cross sections of the 12 C+ 13 C system at energies below the Coulomb barrier are strongly enhanced as a result of the strong CRC effects as compared with those of the 12 C+ 12 C system, while in 12 C+ 13 N system the enhancement of the sub-barrier fusion has not been observed. The above absorption mechanism for the 12 C+ 13 C system explains the lack of the molecular-resonance phenomena observed in the 12 C+ 12 C system. We check the effects of the dipole (E1) transition of the valence nucleon in 13 N (and also in 13 C) due to the core-core Coulomb interaction in the scattering at sub-barrier energies. The effects are not appreciable. (author)

  16. Study of C13/C12 and O18/O16 variations on environments of beach rocks formation in Itaparica island - Bahia

    International Nuclear Information System (INIS)

    Campos, H.S.

    1976-01-01

    Calcium carbonate-cemented beach sands or beach rocks have been observed to occur in the inter tidal zone of many tropical beaches. Near Salvador (Brazil) occurrences are found in several locations on the island of Itaparica. A study of the stable isotope composition (C 13 / C 12 and O 18 / O 16 ) of the cement and the local groundwater was carried out to determine the origin of the carbonate cement. (author)

  17. The MOYA aircraft campaign: First measurements of methane, ethane and C-13 isotopes from West African biomass burning and other regional sources using the UK FAAM aircraft

    Science.gov (United States)

    Allen, Grant; Pitt, Joseph; Lee, James; Hopkins, James; Young, Stuart; Bauguitte, Stéphane; Gallagher, Martin; Fisher, Rebecca; Lowry, David; Nisbet, Euan

    2017-04-01

    Global methane concentrations continue to rise due to an imbalance between sources and sinks. There remains little consensus on the relative components of the manifold source types and their geographical origin. The Global Methane Budget and Yearly Assessments (MOYA) project is tasked with better characterising the global methane budget through an augmented global measurement and modelling programme. As part of MOYA, the UK's Facility for Airborne Atmospheric Measurement (FAAM), will fly four campaigns based out of West Africa and Ascension Island in the period 2017-2019, to focus on the important role of tropical sources. The first of these, to be conducted in late February 2017, will focus on the biomass burning season in West Africa. This paper will present the plan for future FAAM MOYA campaigns and report on our first aircraft data gathered in the West African region. The new addition of an interband cascade laser spectrometer to the FAAM aircraft, flown in this campaign for the first time, promises to provide the first real-time, continuous, and simultaneous, airborne measurements of methane, ethane and methane C-13 isotopologues. Together, these measurements, when interpreted in combination with other trace gases and aerosol measured on the aircraft, will serve as case studies to inform modelling of regional and global fluxes through their isotopic fingerprints.

  18. The isotopic abundance ratio 12C/13C in the solar atmosphere determined from CH-lines in the photospheric spectrum

    International Nuclear Information System (INIS)

    Iversen, Oe.

    1976-01-01

    The R-branch of the (0,0) vibrational band of the violet electronic transition A 2 Δ-X 2 PI of CH is analysed. Isotope wavelength shifts were measured on laboratory spectrograms. The method of synthesising the spectrum was used, and the molecular dissociation equilibrium through the photosphere was computed. 13 CH is not definitely identified in the photospheric spectrum and only upper limits of the 13 C abundance are deduced. The upper limits are sensitive to the local continuum level. A photospheric abundance ratio 12 C/ 13 C greater than the terrestrial value of 90 seems highly probable. (Auth.)

  19. Carbon (14C,13C) and hydrogen (D) isotope measurements on atmospheric methane and its sources (sinks)

    International Nuclear Information System (INIS)

    Levin, I.; Doerr, H.

    1991-07-01

    Concentrations and isotope ratios ( 13 C/ 12 C and D/H) of atmospheric methane and methane from other sources were determined by gas chromatography and mass spectroscopy in specially prepared samples. The results were used for assessing the atmospheric methane inventory. (BBR) [de

  20. C-14 dating and C-13/C-12 isotopic ratio in soils covered by natural vegetation of cerrado-floresta ecosystem at Humaita (AM)/Brazil

    International Nuclear Information System (INIS)

    Gouveia, Susy E.M.; Pessenda, Luiz C.R.; Roveratti, Renato; Cruz, Maria V.L.; Pessin, Glaucia; Aravena, Ramon; Boulet, Rene

    1996-01-01

    The most recent evidences show that in the Amazon region significant climatic changes occurred in the Quaternary, with emphasis to the dry periods during the Pleistocene and increased precipitation in the Holocene. In this region are found areas with characteristics of cerrado, surrounded by tropical rain forest. The evaluations of soil, vegetation and climate interactions for the formation of these areas are important. Carbon isotopes ( 12 C, 13 C, 14 C) have been applied in soil organic matter (SOM) of Humaita region, southern Amazon, to evaluate changes in vegetation communities during the Holocene. Isotopic composition of SOM in the deeper part of the soil profiles, shows that probably in the early Holocene the forest has been in the area today occupied by the cerrado vegetation. The results of SOM in the shallow part of soil profiles characterize perfectly the three types of actual vegetation communities. (author)

  1. Studies to enhance the hyperpolarization level in PHIP-SAH-produced C13-pyruvate

    Science.gov (United States)

    Cavallari, Eleonora; Carrera, Carla; Aime, Silvio; Reineri, Francesca

    2018-04-01

    The use of [1-13C]pyruvate, hyperpolarized by dissolution-Dynamic Nuclear Polarization (d-DNP), in in vivo metabolic studies has developed quickly, thanks to the imaging probe's diagnostic relevance. Nevertheless, the cost of a d-DNP polarizer is quite high and the speed of hyperpolarization process is relatively slow, meaning that its use is limited to few research laboratories. ParaHydrogen Induced Polarization Side Arm Hydrogenation (PHIP-SAH) (Reineri et al., 2015) is a cost effective and easy-to-handle method that produces 13C-MR hyperpolarization in [1-13C]pyruvate and other metabolites. This work aims to identify the main determinants of the hyperpolarization levels observed in C13-pyruvate using this method. By dissecting the various steps of the PHIP-SAH procedure, it has been possible to assess the role of several experimental parameters whose optimization must be pursued if this method is to be made suitable for future translational steps. The search for possible solutions has led to improvements in the polarization of sodium [1-13C]pyruvate from 2% to 5%. Moreover, these results suggest that observed polarization levels could be increased considerably by an automatized procedure which would reduce the time required for the work-up passages that are currently carried out manually. The results reported herein mean that the attainment of polarization levels suitable for the metabolic imaging applications of these hyperpolarized substrates show significant promise.

  2. GC-MS DETERMINATION OF RATIOS OF STABLE-ISOTOPE LABELED TO NATURAL UREA USING [(CN2)-C-13-N-15]UREA FOR STUDYING UREA KINETICS IN SERUM AND AS A MEANS TO VALIDATE ROUTINE METHODS FOR THE QUANTITATIVE ASSAY OF UREA IN DIALYSATE

    NARCIS (Netherlands)

    WOLTHERS, BG; TEPPER, T; WITHAG, A; NAGEL, GT; DEHAAN, THY; VANLEEUWEN, JJ; STEGEMAN, CA; HUISMAN, RM

    A GC-MS determination of urea in serum or spent dialysate is described, using (CN2)-C-13-N-15-labelled urea and assaying the area ratio of labelled to natural urea by mass fragmentographic monitoring of fragments m/e 153 and 156, after its eventual conversion into the trimethylsilylether-derivative

  3. Study of α-monosubstituted methyl acetates by C-13 and H-1 Nuclear Magnetic resonance

    International Nuclear Information System (INIS)

    Silva, E.L.

    1987-01-01

    The substituents effects on the methylene and carbonyl carbons chemical shifts of some α-monosubstituted methyl acetates Z-CH 2 -COOMe(Z=H,Cl,Br,I,OME,SMe,NMe 2 and Me) is studied. Some data of Carbon 13 NMr in the light of the substituents empirical and electronic effects are shown. Solvent and concentration effects on the hydrogen-1 chemical shifts of methyl acetate, bromoacetate and Iodoacetate were interpreted in the light of the Cα-C(O)-bond rotational isomerism. (M.J.C.) [pt

  4. Quantitative evaluation of ruminal methane and carbon dioxide formation from formate through C-13 stable isotope analysis in a batch culture system.

    Science.gov (United States)

    He, Z X; Qiao, J Y; Yan, Q X; Tan, Z L; Wang, M

    2018-04-12

    Methane produced from formate is one of the important methanogensis pathways in the rumen. However, quantitative information of CH4 production from formate has been rarely reported. The aim of this study was to characterize the conversion rate (CR) of formic acid into CH4 and CO2 by rumen microorganisms. Ground lucerne hay was incubated with buffered ruminal fluid for 6, 12, 24 and 48 h. Before the incubation, 13C-labeled H13COOH was also supplied into the incubation bottle at a dose of 0, 1.5, 2.2 or 2.9 mg/g of DM substrate. There were no interactions (P>0.05) between dose and incubation time for all variables evaluated. When expressed as an absolute amount (ml in gas sample) or a relative CR (%), both 13CH4 and 13CO2 production quadratically increased (P<0.01) with the addition of H13COOH. The total 13C (13CH4 and 13CO2) CR was also quadratically increased (P<0.01) when H13COOH was added. Moreover, formate addition linearly decreased (P<0.031) the concentrations of NH3-N, total and individual volatile fatty acids (acetate, propionate and butyrate), and quadratically decreased (P<0.014) the populations of protozoa, total methanogens, Methanosphaera stadtmanae, Methanobrevibacter ruminantium M1, Methanobrevibacter smithii and Methanosarcina barkeri. In summary, formate affects ruminal fermentation and methanogenesis, as well as the rumen microbiome, in particular microorganisms which are directly or indirectly involved in ruminal methanogenesis. This study provides quantitative verification for the rapid dissimilation of formate into CH4 and CO2 by rumen microorganisms.

  5. Evaluation of the production capabilities of 18F, 11C, 13N and 15O PET isotopes at the PET-cyclotron-radiochemistry site of Messina University

    OpenAIRE

    Auditore, Lucrezia; Amato, Ernesto; Italiano, Antonio; Pagano, Benedetta; Baldari, Sergio

    2017-01-01

    The production of 18F, 11C, 13N, and 15O positron emitting radionuclides for PET imaging is usually accomplished in Nuclear Medicine Departments through direct nuclear reactions induced by protons accelerated by compact medical cyclotrons on liquid or gaseous targets. Messina University has funded the construction of a PET-cyclotron-radio-chemistry plant at the Messina University Hospital, equipped with a 11 MeV self-shielded cyclotron. We estimated the expected production yields of these nuc...

  6. Radiation Oxidation Mechanisms in Polyolefins Studied by C-13 Isotopic Labeling

    International Nuclear Information System (INIS)

    Clough, R.L.

    2006-01-01

    Control of oxidative degradation is a critical consideration in most applications involving polymers and radiation. In radiation crosslinking or sterilization, or in the use of polymers in radiation environments (such as nuclear plants), the objective is to minimize degradation as much as possible. In other applications, a controlled, partial degradation is desired to alter processing properties, or to enhance adhesion or solubility. To gain more understanding of the complex processes of radiation oxidation, samples of one important commercial polyolefin, polypropylene, were synthesized in which the three different carbon atoms along the chain were selectively labeled with carbon-13. These samples were subjected to radiation under inert and air atmospheres, and to post-irradiation thermal exposure in air at various temperatures. Analysis of macromolecular radiation-oxidation products was carried out using 13 C NMR and FTIR. Time-dependent plots of oxidation products have been obtained from the NMR measurements, including the post-irradiation oxidation of a sample held at room temperature in air that has been monitored for 2 years. Analysis of volatile oxidation products (CO, CO 2 , and small organic molecules) was accomplished with gas chromatography / mass spectroscopy. The position of the 13 C labels in the degradation products, have been traced back to their positions of origin on the macromolecule, providing insights into the chemical reaction mechanisms through which the products were formed. The major solid-phase products include peroxides and alcohols, both formed at tertiary carbon sites along the chain. Other products include methyl ketones, acids, esters, peresters, and hemiketals formed from reaction at the tertiary carbon, together with in-chain ketones and esters from reaction at the secondary chain carbon. No evidence is found of macromolecular products arising from reactions at the methyl side chain. Significant temperature-dependent differences are apparent; for example much higher yields of chain-end methyl ketones, which are the indicator product of chain scission, are generated for both elevated temperature irradiation and for post-irradiation treatment at elevated temperatures. CO and CO 2 originate primarily from the secondary chain position, with lesser amounts coming from the methyl side-chain, and a small amount from the tertiary chain carbon. Organic volatiles are remarkably specific in their position of origin within the macromolecule, and their structures reflect the oxidative chain cleavage steps through which they form

  7. The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by C-13-labeling experiments

    DEFF Research Database (Denmark)

    Jensen, N.B.S.; Christensen, B.; Nielsen, Jette

    2002-01-01

    Uniformly C-13 labeled glucose was fed to a lactic acid bacterium growing on a defined medium supplemented with all proteinogenic amino acids except glutamate. Aspartate stemming from the protein pool and from the extracellular medium was enriched with C-13 disclosing a substantial de novo...... biosynthesis of this amino acid simultaneous to its uptake from the growth medium and a rapid exchange flux of aspartate over the cellular membrane. Phenylalanine, alanine, and threonine were also synthesized de novo in spite of their presence in the growth medium....

  8. Evaluation of the production capabilities of 18F, 11C, 13N and 15O PET isotopes at the PET-cyclotron-radiochemistry site of Messina University

    Directory of Open Access Journals (Sweden)

    Lucrezia Auditore

    2017-02-01

    Full Text Available The production of 18F, 11C, 13N, and 15O positron emitting radionuclides for PET imaging is usually accomplished in Nuclear Medicine Departments through direct nuclear reactions induced by protons accelerated by compact medical cyclotrons on liquid or gaseous targets. Messina University has funded the construction of a PET-cyclotron-radio-chemistry plant at the Messina University Hospital, equipped with a 11 MeV self-shielded cyclotron. We estimated the expected production yields of these nuclides, accounting for target thickness, production of other radioactive nuclides, and time effects on the irradiated target purity. To this aim, both TALYS code (v. 1.8 and an analytical approach based on EXFOR experimental data were used. The general agreement between the two approaches, and with the available literature data, allows to assess the expected yields at the End of Bombardment, and relative target purities, to be used for further radiopharmaceutical preparation steps.

  9. Pressure-temperature phase diagram of a charge-ordered organic conductor studied by C13 NMR

    Science.gov (United States)

    Itou, T.; Miyagawa, K.; Nakamura, J.; Kanoda, K.; Hiraki, K.; Takahashi, T.

    2014-07-01

    We performed C13 NMR measurements on the quasi-one-dimensional (Q1D) charge-ordered system (DI-DCNQI)2Ag under ambient and applied pressure to clarify the pressure-temperature phase diagram. For pressures up to 15 kbar, the NMR spectra exhibit complicated splitting at low temperatures, indicating a "generalized 3D Wigner crystal" state. In this pressure region, we find that increased pressure causes a decrease in the charge disproportionation ratio, along with a decrease in the transition temperature of the generalized 3D Wigner crystal. In the high-pressure region, near 20 kbar, where a 1D confined liquid crosses over to a 3D Fermi liquid at high temperatures, the ground state is replaced by a nonmagnetic insulating state that is qualitatively different from the generalized 3D Wigner crystal.

  10. Latest paleocene benthic extinction event on the southern tethyan shelf (Egypt): Foraminiferal stable isotopic (delta C-13,delta O-18) records

    OpenAIRE

    Schmitz, B; Speijer, Robert; Aubry, MP

    1996-01-01

    The dramatic global extinction of 35%-50% of benthic foraminifera species in the deep sea in the latest Paleocene and associated negative excursions in delta(13)C and delta(18)O may be related to spreading of warm, saline bottom water from subtropical Tethyan shallow regions over the sea floor worldwide, Our study of neritic sections in Egypt shows that in the southern shallow Tethys, a prominent long-term change in bottom-water chemistry, sedimentation, and benthic foraminifera fauna was ini...

  11. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  12. Multinuclear solid-state high-resolution and C-13 -{Al-27} double-resonance magic-angle spinning NMR studies on aluminum alkoxides

    NARCIS (Netherlands)

    Abraham, A.; Prins, R.; Bokhoven, J.A. van; Eck, E.R.H. van; Kentgens, A.P.M.

    2006-01-01

    A combination of Al-27 magic-angle spinning (MAS)/multiple quantum (MQ)-MAS, C-13-H-1 CPMAS, and C-13-{Al-27} transfer of population in double-resonance (TRAPDOR) nuclear magnetic resonance (NMR) were used for the structural elucidation of the aluminum alkoxides aluminum ethoxide, aluminum

  13. D-seco-Vitamin D analogs having reversed configurations at C-13 and C-14: Synthesis, docking studies and biological evaluation.

    Science.gov (United States)

    Szybinski, Marcin; Sokolowska, Katarzyna; Sicinski, Rafal R; Plum, Lori A; DeLuca, Hector F

    2017-10-01

    Prompted by results of molecular modeling performed on the seco-d-ring-vitamins D, we turned our attention to such analogs, having reversed configurations at C-13 and C-14, as the next goals of our studies on the structure-activity relationship for vitamin D compounds. First, we developed an efficient total synthesis of the "upper" C/seco-d-ring fragment with a 7-carbon side chain. Then, we coupled it with A-ring fragments using Sonogashira or Wittig-Horner protocol, providing the targeted D-seco analogs of 1α,25-dihydroxyvitamin D 3 and 1α,25-dihydroxy-19-norvitamin D 3 possessing a vinyl substituent at C-14 and a double bond between C-17 and C-20. The affinities of the synthesized vitamin D analogs to the full-length recombinant rat VDR were examined, as well as their differentiating and transcriptional activities. In these in vitro tests, they were significantly less active compared to 1α,25-(OH) 2 D 3 . Moreover, it was established that the analogs tested in vivo in rats showed no calcemic potency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Correlation between the 12C+12C, 12C+13C, and 13C+13C fusion cross sections

    Science.gov (United States)

    Notani, M.; Esbensen, H.; Fang, X.; Bucher, B.; Davies, P.; Jiang, C. L.; Lamm, L.; Lin, C. J.; Ma, C.; Martin, E.; Rehm, K. E.; Tan, W. P.; Thomas, S.; Tang, X. D.; Brown, E.

    2012-01-01

    The fusion cross section for 12C+13C has been measured down to Ec.m.=2.6 MeV, at which the cross section is of the order of 20 nb. By comparing the cross sections for the three carbon isotope systems, 12C+12C, 12C+13C, and 13C+13C, it is found that the cross sections for 12C+13C and 13C+13C provide an upper limit for the fusion cross section of 12C+12C over a wide energy range. After calibrating the effective nuclear potential for 12C+12C using the 12C+13C and 13C+13C fusion cross sections, it is found that a coupled-channels calculation with the ingoing wave boundary condition (IWBC) is capable of predicting the major peak cross sections in 12C+12C. A qualitative explanation for this upper limit is provided by the Nogami-Imanishi model and by level density differences among the compound nuclei. It is found that the strong resonance found at 2.14 MeV in 12C+12C exceeds this upper limit by a factor of more than 20. The preliminary result from the most recent measurement shows a much smaller cross section at this energy, which agrees with our predicted upper limit.

  15. Stable-isotope studies

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Structures of bacteriochlorophyll b and the Krasnovskii photoreduction products of chlorophyll a are given. All 55 13 C and 4 15 N NMR transitions in chlorophyl a and its magnesium-free derivative pheophytin a were assigned. ESR of triplet states of chlorophylls a, b, c/sub z/, and c 2 and bacteriochlorophyll a are reported. Experiments in the cultivation of 13 C-enriched morning glory plants indicated that the isotope enrichment can produce observable morphological changes. (U.S.)

  16. Isotope studies in brain diseases

    Energy Technology Data Exchange (ETDEWEB)

    Silfverskioeld, B [Department of Neurology, Soedersjukhuset, S-100 64 Stockholm (Sweden)

    1978-09-01

    Serial pictures of cerebral isotope flow and accumulation after intravenous injection provide several kinds of valuable diagnostic information. The reliability can be increased by using computer-processed pictures on a TV screen and by numerical analysis in accordance with paritcular programs constructed for our routine work. An isotope study should be done when computerized transmission tomography scans have failed to provide a conclusive diagnosis. It should then be performed with optimal technique in order to reduce the need of angiograms.

  17. Isotopic study of Karst water

    International Nuclear Information System (INIS)

    Leskovsek-Sefman, H.

    1985-01-01

    Measurement of the isotopic composition of water formed part of an extended investigation of the water drainage system in the Slovenian Karst. These studies were planned to complement geological and speleological investigations which are already being performed in this area, with the knowledge of the mechanism of changes in the isotopic composition of water in the natural environment on some smaller locations, Planina cave near Postojna where the vertical percolation of meteoric water through the karstified carbonate ceiling was studied and the water catchment areas of some small rivers, Ljubljanica, Rizana and Idrijca. Mass spectrometric investigations of the isotopic composition of some elements ( 18 O, D, 13 C and T) in water and in dissolved carbonates, as well as the isotopic composition of 18 O and 13 C in cave carbonates were performed. The results allow to conclude that the waters in karst aquifers in spite of producing the homogenisation to a great extent, qualitative determination of the retention time and of the prevailing sources for some springs and surface and underground water flows is nevertheless possible. The isotopic composition of 18 O in water and of 18 O and 13 C in dissolved carbonates depends on climatic conditions and on denudation processes. The investigation of cave carbonates revealed that they have different isotopic compositions of 18 O and 13 C because of different locations and also different ages

  18. Probing the possibility of a C-12/C-13 galactic abundance gradient

    International Nuclear Information System (INIS)

    Hawkins, I.

    1990-01-01

    High S/N (equal to or greater than 500) observations of interstellar CH+ with the 3.0 m telescope were performed at Lick Observatory and with the 4.0 m telescope at CTIO, of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a C-12/C-13 abundance gradient in our Galaxy. Previous very high quality optical observations of interstellar CH+ toward five stars within 1 kpc of the Sun have yielded a precise weighted mean C-12/C-13 isotope ratio of 43 plus or minus 4 (1 sigma) (Hawkins, Jura, and Meyer 1985; Hawkins and Jura 1987). The isotope ratios derived toward four lines of sight in the local ISM are uniform within 12 percent. The similarity among these carbon isotope ratios determined in diffuse clouds possessing different physical conditions precludes the possibility that the CH+ molecule is suffering from isotope selective effects in these regions. The precise C-12/C-13 derivable from high quality observations of (12)CH+ and (13)CH+ provide the unique opportunity to probe the homogeneity of the ISM in a large scale and the history of nucleosynthesis in our Galaxy. Since CH+ seems to be the most sensitive probe of C-12/C-13 in the diffuse ISM, observations toward more distant stars located up to 2.5 kpc from the Sun are the best way to study the possibility of a Galactic (C-12/C-13) abundance gradient. The researcher obtained 4232 angstrom data toward all three of the stars mentioned above, 3957 angstrom data toward HD 183143 and HD 157038, and 3745 angstrom data toward HD 157038. Because of the poorer quality of the HD 24432 spectrum, and its weaker CH+ absorption lines, the satellite (13)CH+ line was not detected, and thus only a lower limit on the C-12/C-13 ratio toward this star was obtained. The results obtained from careful reduction and analysis of the data toward these stars in the Northern and Southern Hemispheres are presented

  19. Lithium isotopic separation: preliminary studies

    International Nuclear Information System (INIS)

    Macedo, Sandra Helena Goulart de

    1998-01-01

    In order to get the separation of natural isotopes of lithium by electrolytic amalgamation, an electrolytic cell with a confined mercury cathode was used to obtain data for the design of a separation stage. The initial work was followed by the design of a moving mercury cathode electrolytic cell and three experiments with six batches stages were performed for the determination of the elementary separation factor. The value obtained, 1.053, was ill agreement: with the specialized literature. It was verified in all experiments that the lithium - 6 isotope concentrated in the amalgam phase and that the lithium - 7 isotope concentrated in the aqueous phase. A stainless-steel cathode for the decomposition of the lithium amalgam and the selective desamalgamation were also studied. In view of the results obtained, a five stages continuous scheme was proposed. (author)

  20. Radiogenic age and isotopic studies

    International Nuclear Information System (INIS)

    1991-01-01

    This is one of an annual collection of reports presenting data from the Geochronology Section of the Continental Geoscience Division of the Geological Survey of Canada (GSC). The main purpose of this collection is to make geochronological and other radiogenic isotope data produced by the section available promptly to the geological community. Reports make full presentation of the data, relate these to field settings and make comparatively short interpretations. Other geochronological and isotope data produced in the laboratory but published in outside journals or separate GSC publications are summarized at the end of this report. Reports in this issue give U-Pb zircon ages for rocks in Newfoundland, Yukon Territory, Manitoba, Ontario, and the Northwest Territories; present a compilation of K-Ar ages; and discuss Precambrian activity in New Brunswick, the geochronology of rock from the Northwest Territories, and reconnaissance Nd studies of rocks from the Northwest Territories. (figs., tabs., refs.)

  1. Radiogenic age and isotopic studies

    International Nuclear Information System (INIS)

    1992-01-01

    This is one of an annual collection of reports presenting data from the Geochronology Section of the Continental Geoscience Division of the Geological Survey of Canada (GSC). The main purpose of this collection is to make geochronological and other radiogenic isotope data produced by the section available promptly to the geological community. Reports make full presentation of the data, relate these to field settings and make comparatively short interpretations. Other geochronological and isotope data produced in the laboratory but published in outside journals or separate GSC publications are summarized at the end of this report. Report 5 contains 24 papers from most regions of Canada, but particularly from British Columbia. The Geochronology Laboratory has, over the years, provided substantial U-Pb dating for the Cordilleran Division of the Geological Survey of Canada in Vancouver, and the results of a number of these studies are presented this year. A compilation of K-Ar ages is given. (figs., tabs., refs.)

  2. Laboratory spectra of C-13 ethane

    Science.gov (United States)

    Kurtz, Joe; Reuter, Dennis C.; Jennings, Donald E.; Hillman, John J.

    1991-01-01

    The laboratory infrared spectrum of C-13 monosubstituted ethane has been obtained at high resolution (0.0025/cm) using the McMath Fourier transform spectrometer at Kitt Peak National Observatory in May 1990. A preliminary analysis of the nu12 rQ0 branch (substituted species) suggests that its intensity is 1.15 + or - 0.05 times stronger than the equivalent nu9 branch in the normal (C-12)2H6 species. This result leads to a correction of a previously published estimate for the C-12/C-13 ratio in the atmosphere of Jupiter from about 94 to about 106.

  3. Detection of interstellar (C-13)N toward Zeta Ophiuchi

    International Nuclear Information System (INIS)

    Crane, P.; Hegyi, D.J.

    1988-01-01

    Observations of a diffuse interstellar cloud toward Zeta Oph, obtained with resolution 100,000-150,000 near the 3874.608-A R(0) line of (C-12)N using a coude echelle spectrograph on the 1.4-m telescope at ESO during 1984 and 1985, are reported. Data from 54 20-min runs were fitted to Gaussian line shapes using the line center, depth, and width of the R(0) and R(1) lines of (C-12)N and the line center and depth of the R(0) line of (C-13)N as fitting parameters. The (C-13)N R(0) line, with equivalent width 0.190 + or - 0.020 mA, was detected 173.7 + or - 0.8 mA to the red of (C-12)N R(0); the corresponding isotope abundance ratio, (C-12)N/(C-13)N = 47.3 + 5.5 or -4.4, is shown to be in good agreement with previous measurements for CH(+) (Hawkins et al., 1985). 13 references

  4. Isotope shift studies in gadolinium spectra

    International Nuclear Information System (INIS)

    Ahmad, S.A.; Saksena, G.D.; Venugopalan, A.

    1976-01-01

    Isotope shift studies have been carried out in the gadolinium spectrum using a recording Fabry-Perot spectrometer and gadolinium samples enriched in 156 Gd and 160 Gd isotopes. Isotope shifts Δsigma(156-160) have been recorded in 134 lines in the region 3930-4140 A. Some of these lines involve the recently identified even configuration 4f 8 5d6s of Gd I and the newly classified transition 4f 8 6s-4f 8 6p of Gd II. From the isotope shift measurements of lines involving the 4f 8 6s-4f 8 6p transition in Gd II, the isotope shift, ΔT(156-160)=87 mK, has been obtained for the 4f 8 6s configuration. Electronic configurations have been suggested for a number of energy levels and configuration mixing has been pointed out in certain cases. (Auth.)

  5. Radiogenic age and isotopic studies

    International Nuclear Information System (INIS)

    Parrish, R.R.

    1990-01-01

    This is one of an annual collection of reports presenting data from the Geochronology Section of the Continental Geoscience Division of the Geological Survey of Canada (GSC). The main purpose of this collection is to make geochronological and other radiogenic isotope data produced by the section available promptly to the geological community. Reports make full presentation of the data, relate these to field settings and make comparatively short interpretations. Other geochronological and isotope data produced in the laboratory but published in outside journals or separate GSC publications are summarized at the end of this report. Reports in this issue cover methods for Rb-Sr and Sm-Nd isotopic analyses; 40 Ar- 39 Ar ages for the New Quebec Crater and for basaltic rocks; U-Pb ages for a differentiated mafic sill in the Ogilvie Mountains, plutonic rocks in the Contwoyto-Nose Lakes are, zircons from the Anton Complex, the Clinton-Colden gabbro-anorthosite intrusion, the Himag plutonic suite, the Campbell granite, the Central Gneiss Belt, Silurian granites, a metarhyolite, plagiogranite and gabbro, and the Wage shear zone; Rb-Sr ages for granitic rocks; K-Ar and Rb-Sr geochronology of granites; a compilation of K-Ar ages; ages of archean and proterozoic mylonites and pre-Misi granitoid domes; and reconnaissance geochronology of Baffin Island

  6. Metabolic studies in man using stable isotopes

    International Nuclear Information System (INIS)

    Faust, H.; Jung, K.; Krumbiegel, P.

    1993-01-01

    In this project, stable isotope compounds and stable isotope pharmaceuticals were used (with emphasis on the application of 15 N) to study several aspects of nitrogen metabolism in man. Of the many methods available, the 15 N stable isotope tracer technique holds a special position because the methodology for application and nitrogen isotope analysis is proven and reliable. Valid routine methods using 15 N analysis by emission spectrometry have been demonstrated. Several methods for the preparation of biological material were developed during our participation in the Coordinated Research Programme. In these studies, direct procedures (i.e. use of diluted urine as a samples without chemical preparation) or rapid isolation methods were favoured. Within the scope of the Analytical Quality Control Service (AQCS) enriched stable isotope reference materials for medical and biological studies were prepared and are now available through the International Atomic Energy Agency. The materials are of special importance as the increasing application of stable isotopes as tracers in medical, biological and agricultural studies has focused interest on reliable measurements of biological material of different origin. 24 refs

  7. Study of neutron-deficient Sn isotopes

    International Nuclear Information System (INIS)

    Auger, G.

    1982-05-01

    The formation of neutron deficient nuclei by heavy ion reactions is investigated. The experimental technique is presented, and the results obtained concerning Sn et In isotopes reported: first excited states of 106 Sn, high spin states in 107 Sn and 107 In; Yrast levels of 106 Sn, 107 Sn, 108 Sn; study of neutron deficient Sn and In isotopes formed by the desintegration of the compound nucleus 112 Xe. All these results are discussed [fr

  8. Field experimentation in isotope-aided studies

    International Nuclear Information System (INIS)

    Zapata, F.

    1990-01-01

    Isotopic-aided studies involve the application of isotopically labelled fertilizer as tracers for the quantitative and precise determination of the fate of specific nutrient elements in the soil/plant system. The planning of isotopic-aided studies requires a different approach from that followed in the design of normal fertilizer trials because of the cost and supply of isotopically labelled materials, the use of highly specialized equipment and the need for skillful trained staff in the use of isotope techniques both in the field/greenhouse and the laboratory. This report is intended to highlight the main points to be considered while applying those techniques in the field or greenhouse. It has been well established that nuclear techniques are a powerful tool in agricultural research. One should take advantage of the use of such techniques if the following criteria are met: The isotope method is the only way to solve a particular question or to obtain a specific piece of information. There are other methods available for such a purpose but the nuclear method provides a direct and quick means to obtain the needed information resulting in higher economic return

  9. Study of the isotopic contamination with the Grenoble isotope separator

    International Nuclear Information System (INIS)

    Boge, Marc

    1970-01-01

    To know the limits of enrichment of the Grenoble electromagnetic isotope separator, we have studied the scattering of ions on the residual gas, and the chromatism. With Neodymium (Nd + ≅ 500 μA, NdO + ≅ 120 μA, Nd 2+ ≅ 70 μA) the second magnet has been used to analyse the ions which passed through the first stage slit. Therefore, we have measured the scattering with and without charge exchange of Nd + and the dissociation of NdO + . The chromatism has been studied by means of an electrostatic analyser, as a third stage. The limits of enrichment are obtained for Argon, Uranium and Neodymium. (author) [fr

  10. Biological 12C-13C fractionation increases with increasing community-complexity in soil microcosms

    DEFF Research Database (Denmark)

    Yang, Weijun; Magid, Jakob; Christensen, Søren

    2014-01-01

    -rates and determine the trophic level of organisms in biological systems. While it is widely accepted that 15N-accumulates in natural food-chains, it is disputed to which extent this is the case for C-13. We constructed sand-microcosms inoculated with a dilution series of soil organisms and amended with glucose......Isotope fractionation is a ubiquitous phenomenon in natural ecosystems. When chemical elements move through food chains, natural isotope ratios change because biological processes tend to discriminate against heavier isotopes. This effect can be used to trace flows of matter, estimate process...

  11. Laser isotope separation studies in JAERI

    International Nuclear Information System (INIS)

    Arisawa, Takashi; Shiba, Koreyuki

    1986-01-01

    For uranium enrichment, Japan Atomic Energy Research Institute (JAERI) has been studying atomic vapor laser isotope separation since 1976, in addition to such separation methods as gas diffusion, chemical exchange and gas-dynamic techniques. Studies carried out to date in JAERI is briefly summarized in the first part of the report. Then, some major separation techniques which have been studied in JAERI are outlined, and typical results obtained are presented. A large part is devoted to the multiple-photon photoionization technique, which is commonly known as the atomic laser isotope separation method for uranium enrichment. It has such advantages as 1) very high spectral selectivity for the relevant isotope and 2) highly improved photoionizing effect by means of two- and three-step resonance photoionization processes. Here, the atomic laser isotope separation method is discussed in detail with respect to the evaporation process, energy levels, photoionization, selectivity, photoionization schemes, ion recovery, separation in macroscopic amounts, and separation of trace amounts of isotopes. Typical observed and claculated results related to these subjects are shown. In addition, the report briefly describes some other separation processes including laser induced chemical reaction, multiple photo-dissociation, multiple-photo excitation and UV dissociation, laser induced thermal diffusion, and laser centrifugation. (Nogami, K.)

  12. Isotopic studies in soil and plant nutrition

    International Nuclear Information System (INIS)

    Pasricha, N.S.

    2001-01-01

    One of the most important peaceful applications of isotopes is in research for the enhancement of our understanding for increased crop production and better management of resources with higher economic efficiency and environmental safety. Nuclear techniques helped in generating useful information on such aspects as use-efficiency of fertilizer nutrients, quantifying their losses from soil and their biological transformations. Such information was, hitherto, obtained indirectly by conventional methods. Radio and stable isotopes have also been successfully employed for getting information in such diverse fields as soil erosion, turnover of soil organic matter, pesticide retention in soil ground water recharge etc. The property of 137 Cs adhering tightly to certain exchange surface in soil and its chemically inert nature has made it a useful tool for soil erosion studies. In this paper, applications of isotopes in the research and other such studies as degradation, movement and retention of pesticides, movement of nitrate in soil, biological and ammoniacal nitrogen fixation in soil is discussed

  13. Applications of Radium Isotopes to Ocean Studies

    Energy Technology Data Exchange (ETDEWEB)

    Moore, W. S. [Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC (United States)

    2013-07-15

    With half-lives ranging from 3.7 days to 1600 a, naturally occurring radium isotopes have been used to study a variety of processes in the ocean. New techniques, which allow rapid analyses of the short lived isotopes, {sup 224}Ra (half-life = 3.7 days) and {sup 223}Ra (half-life = 11 days), have lead to many novel ways to apply radium to oceanography. This paper will focus on how the use of these isotopes has led to breakthroughs in quantifying: (1) the residence time of water in estuaries, (2) coastal ocean mixing rates and (3) submarine groundwater discharge (SGD). With this new understanding of rates and fluxes in the near shore environment, scientists and coastal managers are now able to evaluate sources of nutrients, carbon, and metals and their impact on the coastal ocean. For example, it is now known that SGD rivals rivers as a nutrient source to many coastal environments. (author)

  14. Isotope effects: definitions and consequences for pharmacologic studies

    International Nuclear Information System (INIS)

    Van Langenhove, A.

    1986-01-01

    The use of stable isotope-labeled compounds for pharmacologic studies requires careful consideration of the nature of the stable isotope label (2H, 13C, 15N, 18O) and its position of incorporation in the molecule. When deuterium is used, improper positioning can lead to significant primary isotope effects. Primary isotope effects occur when the breaking of the bond to the heavy isotope is the rate-limiting step in a reaction (or metabolic transformation). A reaction will proceed slower for the molecule with the heavy isotope label because of the mass difference between the light and the heavy isotope. In addition to these primary isotope effects, smaller but nevertheless important secondary isotope effects, physicochemical isotope effects, active hydrogen/deuterium exchange, or isotope effects associated with either the enzyme-catalyzed biotransformation or the mass spectrometric ionization and fragmentation can be operative. In mechanistic studies, isotope effects are used to their advantage; however, in pharmacokinetic studies, the occurrence of isotope effects can lead to grossly misleading biologic and analytic results: the metabolism of the drug will differ when in vivo isotope effects are operative, and isotope effects occurring during the analysis procedure will obscure the true metabolic profile of the drug

  15. The 12C/13C ratio in stellar atmospheres. VI. Five luminous cool stars

    International Nuclear Information System (INIS)

    Hinkle, K.H.; Lambert, D.L.; Snell, R.L.

    1976-01-01

    The isotopic abundance ratio, 12 C/ 13 C, is derived from the CO vibration rotation lines at 1.6 and 2.3 μ for five cool luminous stars by a simple curve-of-growth technique. A new analysis of CN lines at 8000 A is also described for α Sco and α Ori. Results derived independently from CO and CN are in agreement. Final results are 12 C/ 13 C=7 +- 2(α Ori), 12 +- 3(α Sco), 7 +- 3(β Peg), 25 +- 7(chi Cyg), 17 +- 4(α Her), and 7 +- 1.5(α Boo). The α Boo analysis provides a check on the CO curve-of-growth technique; the 12 C/ 13 C ratio from the 2.3 μ CO lines is in good agreement with the previously determined ratio from CN and CH lines

  16. Radiochemical studies of neutron deficient actinide isotopes

    International Nuclear Information System (INIS)

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, 242 Bk, was produced with a cross-section of approximately 10 μb in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, αxn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,αxn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z 1 + Z 2 = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,αxn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of 228 Pu, 230 Pu, 232 Cm, or 238 Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes

  17. Radiochemical studies of neutron deficient actinide isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K.E.

    1978-04-01

    The production of neutron deficient actinide isotopes in heavy ion reactions was studied using alpha, gamma, x-ray, and spontaneous fission detection systems. A new isotope of berkelium, /sup 242/Bk, was produced with a cross-section of approximately 10 ..mu..b in reactions of boron on uranium and nitrogen on thorium. It decays by electron capture with a half-life of 7.0 +- 1.3 minutes. The alpha-branching ratio for this isotope is less than 1% and the spontaneous fission ratio is less than 0.03%. Studies of (Heavy Ion, pxn) and (Heavy Ion, ..cap alpha..xn) transfer reactions in comparison with (Heavy ion, xn) compound nucleus reactions revealed transfer reaction cross-sections equal to or greater than the compound nucleus yields. The data show that in some cases the yield of an isotope produced via a (H.I.,pxn) or (H.I.,..cap alpha..xn) reaction may be higher than its production via an xn compound nucleus reaction. These results have dire consequences for proponents of the ''Z/sub 1/ + Z/sub 2/ = Z/sub 1+2/'' philosophy. It is no longer acceptable to assume that (H.I.,pxn) and (H.I.,..cap alpha..xn) product yields are of no consequence when studying compound nucleus reactions. No evidence for spontaneous fission decay of /sup 228/Pu, /sup 230/Pu, /sup 232/Cm, or /sup 238/Cf was observed indicating that strictly empirical extrapolations of spontaneous fission half-life data is inadequate for predictions of half-lives for unknown neutron deficient actinide isotopes.

  18. Measuring glucose cerebral metabolism in the healthy mouse using hyperpolarized C-13 magnetic resonance

    DEFF Research Database (Denmark)

    Mishkovsky, Mor; Anderson, Brian; Karlsson, Magnus

    2017-01-01

    The mammalian brain relies primarily on glucose as a fuel to meet its high metabolic demand. Among the various techniques used to study cerebral metabolism, C-13 magnetic resonance spectroscopy (MRS) allows following the fate of C-13-enriched substrates through metabolic pathways. We herein...... glucose is split into 3-carbon intermediates by aldolase. This unique method allows direct detection of glycolysis in vivo in the healthy brain in a noninvasive manner....... demonstrate that it is possible to measure cerebral glucose metabolism in vivo with sub-second time resolution using hyperpolarized C-13 MRS. In particular, the dynamic C-13-labeling of pyruvate and lactate formed from C-13-glucose was observed in real time. An ad-hoc synthesis to produce [2,3,4,6,6-H-2(5), 3...

  19. Isotope studies on soil and fertilizer nitrogen

    International Nuclear Information System (INIS)

    Olson, R.A.

    1979-01-01

    Reductions in isotope cost in the 1960s and equipment innovations, have extended compared to 1940, the research of soil and plant scientists so that 15 N is now an indispensable tool when working with N. Leadership of FAO/IAEA coordinated research programmes and the Nitrogen Laboratory of the Tennessee Valley Authority helped greatly in bringing about this expanded usage. Recognized isotope effects are of insufficient magnitude to invalidate tracer measurements of field crop uptake in the treatment year if enrichment of 0.3 at.% excess 15 N or greater is employed. Thus, use of 15 N depleted tracer with potential of 0.366% 15 N differential from the standard isotope ratio of N in air is feasible. Its manufacture has allowed further economy in the isotope tag and ultimate treatment of field-scale plots. Interest in Δ 15 N measurements for predicting the NO - 3 contaminant source in surface and ground waters has depreciated. Variations in natural isotope ratio of soil N commonly exceed the differences in Δ 15 N values of the presumed source materials. 15 N provides the only correct measure of fertilizer N utilization efficiency. The field study examples of irrigated maize demonstrate that little or no fertilizer N is likely to escape the root zone where the rate applied does not exceed that required for maximum yield; also, that light and frequent irrigations afford higher yields than heavier, less frequent irrigations. Delaying fertilizer N applications until the crop is well established affords not only higher yields, but greater residual fertilizer N for future crops. Measured effective root activity for absorbing NO - 3 has been invaluable in estimating fertilizer requirements of a crop in relation to residual mineral N in soil at planting and projecting the depth at which the NO - 3 becomes an environmental hazard. The tag likewise is indispensable in determining symbiotic N fixation

  20. Application of environmental isotopes in water resources studies in Latin America

    International Nuclear Information System (INIS)

    Aravena, Ramon

    2001-01-01

    The development of urban centers and economical activities, such as agriculture and mining, in Latin America are intimately linked to the availability of water resources. The increasing demand for water and the risks associated to contamination have generated numerous studies related to the evaluation of water resources in this region. In the specific case of groundwater studies, environmental isotopes have played a significant role in these studies ( 18 O, 2 H, 14 C, 13 C). Groundwater provides about 50-60 % of the water resources used in Latin America. Large urban centers such as Lima (Peru), Managua (Nicaragua) and San Jose (Costa Rica) depend mainly on groundwater as a water supply for the population. The agriculture sector is also a major user of groundwater. The Isotope Hydrology Section of the International Atomic Energy Agency based in Vienna has mainly promoted the application of isotope techniques in Latin America. Most of these applications have focussed on the evaluation of the origin and residence time of the groundwater. The groundwater origin is intimately linked to recharge areas whose evaluation is key for the water balance of the aquifer. The evaluation of the groundwater residence time provides information that is relevant for the management of the groundwater system. This presentation will discuss the basic principles of the application of environmental isotopes in hydrology and it will review the current application of isotope techniques in Latin America. Case studies from different Latin American countries will be used to illustrate the main type of application of isotope techniques in groundwater studies in this region (au)

  1. Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

    OpenAIRE

    Hannah B Vander Zanden; David X Soto; Gabriel J Bowen; Keith A Hobson; Keith A Hobson

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicat...

  2. Expanding the Isotopic Toolbox: Applications of Hydrogen and Oxygen Stable Isotope Ratios to Food Web Studies

    OpenAIRE

    Vander Zanden, Hannah B.; Soto, David X.; Bowen, Gabriel J.; Hobson, Keith A.

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicatio...

  3. Isotope shift studies in gadolinium spectra

    International Nuclear Information System (INIS)

    Ahmad, S.A.; Saksena, G.D.; Venugopalan, A.

    1975-01-01

    Isotope shift studies have been carried out in the gadolinium spectrum using a recording Fabry-Perot spectrometer and gadolinium samples enriched in 156 Gd and 160 Gd isotopes. The source used is a liquid-nitrogen-cooled hollow cathode with Ne as the carrier gas and operating at about 30 mA. Isotope shifts Δsigma (156-160) have been recorded in 350 transitions of Gd I and Gd II. In the case of the Gd I spectrum, the transitions studied presently involve almost all the reported configurations assigned to the energy levels of Gd I. The odd configurations are 4f 7 5d6s 2 , 4f 7 5d 2 6s, 4f 7 5d 3 , 4f 8 6s6p, 4f 7 5d6s7s and 4f 7 6s 2 6p, and the even ones are 4f 8 6s 2 , 4f 7 5d6s6p, 4f 7 6s 2 6p, 4f 8 5d6s and 4f 7 5d 2 6p. In the case of the Gd II spectrum isotope shifts in the lines of the newly classified transition 4f 8 6s - 4f 8 6p have been studied and isotope shift ΔT (156-160) 87 mK has been obtained for the 4f 8 6s configuration. The other transitions of Gd II involve the odd configurations 4f 7 5d6s, 4f 7 6s 2 , 4f 7 5d 2 and 4f 8 6p and the even ones 4f 7 6s6p, 4f 8 5d, 4f 7 5d6p and 4f 8 6p. The ΔT (156-160) of a large number of odd and even levels of Gd I and Gd II have been evaluated. Electronic configurations have been suggested for a number of energy levels and configuration mixing has been pointed out in certain cases. A number of hitherto unreported transitions have been found and using a monoisotopic sample of Gd, that is 160 Gd, their separations from the closest listed transitions have been measured. (author)

  4. Dynamic isotope studies in liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Weits, J

    1978-01-01

    Much information in the field of liver research has been gained by dynamic isotope studies. Clinically, these studies can help to settle selection criteria for different types of surgical shunt, which relieve the complications of portal hypertension. By performing splenoportoscintigraphy, splenic and portal vein thrombosis can be easily and safely excluded. So-called hypoxaemia of cirrhosis can most easily be diagnosed. Suprahepatic caval vein obstruction in a patient with cryptogenic liver disease is easily excluded by a radionuclide cavogram after injection of pertechnetate into a foot vein.

  5. Experimental study on isotope fractionation of evaporating water of different initial isotopic composition

    International Nuclear Information System (INIS)

    Pooja Devi; Jain, A.K.; Rao, M.S.; Kumar, B.

    2014-01-01

    The studies of evaporative isotopic fractionation in controlled conditions are of particular importance for understanding the mechanism of evaporation fractionation in natural conditions. We present the measurements of the average isotopic fractionation factors during the evaporation of water having different initial isotopic compositions at constant temperature. The results show that the isotopic composition of residual water become more enriched over the time and the initial isotopic composition of evaporating water has considerable effect on the average isotopic fractionation factors. The average isotopic fractionation factors in evaporation of Water A and Water B under the present experimental conditions were found to be 0.9817 ± 0.0044 and 0.9887 ± 0.0031 for oxygen and 0.9178 ± 0.0182 and 0.9437 ± 0.0169 for hydrogen, respectively. The findings of this work should lead to a better understanding and use of stable isotope techniques in isotope hydrology by using a simple technique of evaporation pan. (author)

  6. Use of Isotopes for Studying Reaction Mechanisms

    Indian Academy of Sciences (India)

    In the first part of this series, we discussed how isotopes can be used as markers to determine the nature of intermediates in chemical reactions. The second part covered the effect of isotopes on equilibria and reactions, in processes where the bond to the isotopic a tom is broken. We showed with specific examples how.

  7. NMR studies of isotopically labeled RNA

    Energy Technology Data Exchange (ETDEWEB)

    Pardi, A. [Univ. of Colorado, Boulder, CO (United States)

    1994-12-01

    In summary, the ability to generate NMR quantities of {sup 15}N and {sup 13}C-labeled RNAs has led to the development of heteronuclear multi-dimensional NMR techniques for simplifying the resonance assignment and structure determination of RNAs. These methods for synthesizing isotopically labeled RNAs are only several years old, and thus there are still relatively few applications of heteronuclear multi-dimensional NMR techniques to RNA. However, given the critical role that RNAs play in cellular function, one can expect to see an increasing number of NMR structural studies of biologically active RNAs.

  8. C-12/C-13 Ratio in Ethane on Titan and Implications for Methane's Replenishment

    Science.gov (United States)

    Jennings, Donald E.; Romani, Paul N.; Bjoraker, Gordon L.; Sada, Pedro V.; Nixon, Conor A.; Lunsford, Allen W.; Boyle, Robert J.; Hesman, Brigette E.; McCabe, George H.

    2009-01-01

    The C-12/C-13 abundance ratio in ethane in the atmosphere of Titan has been measured at 822 cm(sup -1) from high spectral resolution ground-based observations. The value 89(8), coincides with the telluric standard and also agrees with the ratio seen in the outer planets. It is almost identical to the result for ethane on Titan found by the composite infrared spectrometer (CIRS) on Cassini. The C-12/C-13 ratio for ethane is higher than the ratio measured in atmospheric methane by Cassini/Huygens GCMS, 82.3(l), representing an enrichment of C-12 in the ethane that might be explained by a kinetic isotope effect of approximately 1.1 in the formation of methyl radicals. If methane is being continuously resupplied to balance photochemical destruction, then we expect the isotopic composition in the ethane product to equilibrate at close to the same C-12/C-13 ratio as that in the supply. The telluric value of the ratio in ethane then implies that the methane reservoir is primordial.

  9. Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment

    Science.gov (United States)

    Jennings, Donald E.; Nixon, C. A.; Romani, P. N.; Bjoraker, G. L.; Sada, P. V.; Lunsford, A. W.; Boyle, R. J.; Hesman, B. E.; McCabe, G. H.

    2009-01-01

    As the .main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS(exp 1) and from the ground and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes.

  10. The C-12/C-13 abundance ratio in Comet Halley

    International Nuclear Information System (INIS)

    Wyckoff, S.; Lindholm, E.; Wehinger, P.A.; Peterson, B.A.; Zucconi, J.M.

    1989-01-01

    The individual (C-13)N rotational lines in Comet Halley are resolved using high-resolution spectra of the CN B2Sigma(+)-X2Sigma(+) (0,0) band. The observe C-12/C-13 abundance ratio excludes a site of origin for the comet near Uranus and Neptune and suggests a condensation environment quite distinct from other solar system bodies. Two theories are presented for the origin of Comet Halley. One theory suggest that the comet originated 4.5 Gyr ago in an inner Oort cloud at a heliocentric distance greater than 100 AU where chemical fractionation led to the C-13 enrichment in the CN parent molecule prior to condensation of the comet nucleus. According to the other, more plausible theory, the comet nucleus condensed relatively recently from the interstellar medium which has become enriches in C-13 and was subsequently gravitationally captured by the solar system. 107 refs

  11. Study of groundwater recharge in Rechna Doab using isotope techniques

    International Nuclear Information System (INIS)

    Sajjad, M.I.; Tasneem, M.A.; Ahmed, M.; Hussain, S.D.; Khan, I.H.; Akram, W.

    1992-04-01

    Isotopic studies were performed in the Rechna Doab area to understand the recharge mechanism, investigate the relative contributions from various sources such as rainfall, rivers and canal system and to estimate the turn over times and replenishment rate of groundwater. The isotopic data suggest that the groundwater in the project area can be divided into different zones each having its own characteristic isotopic composition. The enriched isotopic values show rain recharge and depleted isotopic values are associated with river/canal system while the intermediate isotopic values show a mixing of two or more sources of water. The major contribution, however, comes from canal system. The isotopic data suggest that there is no quick movement of groundwater in the area. 18 figs. (author)

  12. Impact of transamination reactions and protein turnover on labeling dynamics in C-13-labeling experiments

    DEFF Research Database (Denmark)

    Grotkjær, Thomas; Åkesson, M.; Christensen, Bjarke

    2004-01-01

    A dynamic model describing carbon atom transitions in the central metabolism of Saccharomyces cerevisiae is used to investigate the influence of transamination reactions and protein turnover on the transient behavior of C-13-labeling chemostat experiments. The simulations performed suggest...... that carbon exchange due to transamination and protein turnover can significantly increase the required time needed for metabolites in the TCA cycle to reach isotopic steady state, which is in agreement with published experimental observations. On the other hand, transamination and protein turnover will speed...... behavior until after three residence times. These observations suggest that greater caution should be used while also pointing to new opportunities in the design and interpretation of C-13-labeling experiments....

  13. Isotopes in soil-plant nutrition studies

    International Nuclear Information System (INIS)

    1962-01-01

    Radioisotopes have greatly facilitated investigating the characteristics of plant nutrients in the soil, in measuring soil moisture, in studying the uptake of nutrients by plants and in devising efficient methods of fertilizer application, and are now being widely used in soil-plant nutrition research. A recent international symposium on the use of radioisotopes in soil-plant nutrition studies showed the varied ways in which isotopes can contribute to agricultural production by helping to investigate soil characteristics and soil-plant relationships. The symposium, jointly sponsored by the International Atomic Energy Agency and the Food and Agriculture Organization of the United Nations, was held in Bombay from 26 February to 2 March 1962, at the invitation of the Government of India

  14. Some isotope hydrological studies in Southern Africa

    International Nuclear Information System (INIS)

    Verhagen, B.Th.

    2001-01-01

    Four case studies involving the use of the environmental isotopes 14 C and 3 H, in the and to semi-arid Kalahari region of Southern Africa are described and general conclusions regarding the qualitative aspects of recharge and discharge characteristics of the systems are based on these measurements. In each of the studies, diffuse, local recharge was found to be the dominant recharge mechanism. Recharge via river beds was found to be limited at the regional scale. The balancing discharge mechanism for groundwater was found to be via evapotranspiration. Groundwater salinity and mineralisation as well as the regional hydrogeology are controlled by geological structure rather than lithologies or residence times and the absence of hypersaline groundwaters indicates that the aquifers are periodically flushed during pluvial periods, thus pointing to long-term hydroclimatic controls over the observed present-day hydrology. (author)

  15. Hydrogeological and isotopic studies for selected springs in Sinai Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Hamza, M S; Awad, M A; El-gamal, S A [Atomic Energy Authority, Cairo Egypt and Middle Eastern Regional Radioisotope Center for The Arab Countries, Dokki, 12311, Cairo (Egypt); Hammad, F A [Desert Research Centre, Materia, Cairo, (Egypt)

    1995-10-01

    This paper deals with the hydrogeology and isotopic composition of water samples collected from selected spring in sinai (e.g. Algudierate, Alqusiema, qidis and Isram) in order to identify their genesis, their interaction with the host rocks and mixing trend. Results of isotopic composition have indicated the similarity in the hydrogeologic situation of Ain qidis and Ain-al-gudierate, while Ain Isram has shown a marked difference in its stable isotope and this could be due to evaporation effect. The isotopic and hydrochemical constituents of the studied springs reflect eater of a meteoric origin with a possible contamination from surficial materials (evaporates) and deeper aquifers. 6 figs., 2 tabs.

  16. Isotope angiocardiography. Method and preliminary own studies

    Energy Technology Data Exchange (ETDEWEB)

    Stepinska, J; Ruzyllo, W; Konieczny, W [Centrum Medyczne Ksztalcenia Podyplomowego, Warsaw (Poland)

    1979-01-01

    Method of technetium isotope 99 m pass through the heart recording with the aid of radioisotope scanner connected with seriograph and computer is being presented. Preliminary tests were carried out in 26 patients with coronary disease without or with previous myocardial infarction, cardiomyopathy, ventricular septal defect and in patients with artificial mitral and aortic valves. The obtained scans were evaluated qualitatively and compared with performed later contrast X-rays of the heart. Size of the right ventricle, volume and rate of left atrial evacuation, size and contractability of left ventricle were evaluated. Similarity of direct and isotope angiocardiographs, non-invasional character and repeatability of isotope angiocardiography advocate its usefulness.

  17. Substitution effect in nuclear magnetic resonance of C-13: α methoxicyclohexanones

    International Nuclear Information System (INIS)

    Lopez Holland, M.A.G.

    1984-01-01

    Eletronic and steric interactions between the carbonyl and methoxyl groups in α-methoxicyclohexanones by H-1 and C-13 nuclear magnetic resonance spectroscopy (n.m.r) is studied. Interpretation of H-1 n.m.r measurements based on the carbonyl group anisotropy is made. The asigment of spectral lines to specific nuclear by Lanthanide Shift Reagent Experiments is confirmed. Interpretation of C-13 n.m.r. spectra with respect to molecular effects and emphirical relationships associated with the substituent was analysed. The C-13 chemical shift asignment by comparison with results of partially (SFORD) and fully decompled spectra and also by relating the measured chemical shift with values cited in the literature for similar compounds are made. A qualitative study using I.R. spectroscopy in attempt to evaluate the predominance of one the conformers of the studied compounds in solutions of n-hexan and chloroform is made. (M.J.C.) [pt

  18. Li Isotope Studies of Olivine in Mantle Xenoliths by SIMS

    Science.gov (United States)

    Bell, D. R.; Hervig, R. L.; Buseck, P. R.

    2005-01-01

    Variations in the ratio of the stable isotopes of Li are a potentially powerful tracer of processes in planetary and nebular environments [1]. Large differences in the 7Li/6Li ratio between the terrestrial upper mantle and various crustal materials make Li isotope composition a potentially powerful tracer of crustal recycling processes on Earth [2]. Recent SIMS studies of terrestrial mantle and Martian meteorite samples report intra-mineral Li isotope zoning [3-5]. Substantial Li isotope heterogeneity also exists within and between the components of chondritic meteorites [6,7]. Experimental studies of Li diffusion suggest the potential for rapid isotope exchange at elevated temperatures [8]. Large variations in 7Li, exceeding the range of unaltered basalts, occur in terrestrial mantle-derived xenoliths from individual localities [9]. The origins of these variations are not fully understood.

  19. Preliminary economic feasibility study of MIP (Medical Isotopes Producer)

    International Nuclear Information System (INIS)

    Mon, G. H.; O, S. Y.

    2004-01-01

    Preliminary economic feasibility study of MIP (Medical Isotopes Producer), which is used liquid nuclear fuel to produce medical isotopes of Mo-99 and Sr-89, was performed. To do this, this study was estimated the IRR(Internal Rate of Return) and PBP(Pay-back Period) about optimistic and pessimistic cases for market penetration of Asia and U.S.A. isotope markets. And sensitivity analysis is also performed about capital cost and price of Mo-99 and Sr-89. According to the results, IRR was between 14.9% and 24.3%, and PBP was between 4.8 years and 7.8 years. These suggest that MIP has economic merits. MIP can produce other medical isotopes such as Sr-90, I-131, Xe-133, Cs-137. So, it is necessary to do cost-benefit analysis considering production of these other isotopes

  20. Hydrochemical and isotope study of Lake Titicaca

    International Nuclear Information System (INIS)

    Gonfiantini, R.; Cioni, R.; Paredes, M.

    2002-01-01

    The chemical and isotopic compositions of Lake Titicaca and its inflow waters (precipitation, tributaries, groundwater) were determined with the aim of establishing the lake chemical and isotope balance. The three main regions of the lake, i.e. the Lago Mayor, the eastern and the western basins of Lago Menor, connected in cascade, show significant chemical and isotopic differences. Chloride and sodium balance indicates that an average of about 92% of the inflow water evaporates, and the remaining 8 % is lost through Rio Desaguadero and infiltration. The balance of each basin is also obtained, including the inter-basin fluxes. The stable isotope balance in not possible because no data are available on the mean atmospheric vapour isotopic composition. However, this was tentatively computed using the fluxes obtained from chemistry. The vapour δ-values are slightly more negative than those of rainfall. Tritium, noble gases and chloro-fluoro-carbons in vertical profiles show that the lake is vertically well mixed and there is no water segregation at depth. (author)

  1. Isotopic approach to the provenance study of artifacts

    International Nuclear Information System (INIS)

    Mabuchi, Hisao

    1994-01-01

    Isotopic abundance ratios, which are proved to be generally constant, are known to vary, for certain elements, from one place to another. Light elements, such as hydrogen, lithium, boron, carbon, nitrogen, oxygen and sulfur, show measurable variations of their isotope ratios due to isotopic fractionation which takes place during geochemical or biochemical processes. Isotope ratios of strontium and lead vary due to the decay of long-lived radioactive nuclides 87 Rb and 238 U- 235 U- 232 Th, respectively. Such isotopic anomalies can be applicable to provenance studies of archaeological objects. Thus, 13 C/ 12 C, 18 O/ 16 O, or 87 Sr/ 86 Sr were used to examine the authenticity of Greek marble statues. Also, lead isotope ratios have been used since mid-1960s extensively for provenance studies of glasses and bronzes of different civilizations. As an example, the author presents a series of his own works on lead isotope ratios applied to ancient Japanese bronzes, which are summarized as follows. 1) It was generally observed that lead isotope ratios reflect difference in culture to which bronzes belong. 2) Mirrors in the Western Han period (206 B.C. - A.D.8) are clearly distinguished by lead isotope ratios from those made after the mid-Eastern Han period (ca.A.D.150 - 300). 3) Korean mirrors and weapons excavated from the Yayoi sites contain lead of easily recognizable Mississippi Valley type. 4) Bronze objects made in Japan (imitative Han style mirrors, Dotaku, imitative weapons, arrowheads etc.) in the Yayoi and Kofun periods are classified by lead isotope ratios in the following order: the Korean mirror type to the Western Han mirror type in the Yayoi period and the mid- to post- Han mirror type in the Kofun period. 5) Indigenous Japanese lead seems to have been used after the mid-7th century. (J.P.N.)

  2. Phenotypic characterization of glucose repression mutants of Saccharomyce cerevisiae usinge experiments with C-13-labelled glucose

    DEFF Research Database (Denmark)

    Vijayendran, Raghevendran; Gombert, A.K.; Christensen, B.

    2004-01-01

    techniques, which do not provide information about the integrated response a specific genetic modification has on the cellular function. In this study we have performed phenotypic characterization of several mutants of the yeast Saccharomyces cerevisiae through the use of experiments with C-13-labelled...

  3. A latitudinal study of oxygen isotopes within horsehair

    Science.gov (United States)

    Thompson, E.; Bronk Ramsey, C.; McConnell, J. R.

    2016-12-01

    This study aims to explore the hypothesis that 'if oxygen isotope ratios deplete with decreasing temperature then a study of oxygen isotope ratios within horsehair from Oxfordshire to Iceland will show a latitudinal depletion gradient'. By looking at oxygen isotope values at different geographical positions, we can track the relationship with latitude and with different regional climate features. This will provide a firmer understanding of how to compare climate records from different locations. Additionally, a comparison of the horse breeds from this study to those analysed within previous studies will create an even better understanding of the intra-species variation within the δ18O values of horsehair. A total of 24 horses were sampled on the 7th March from Thordale Stud in Shetland, the Icelandic Food And Veterinary Authority in Iceland, the Exmoor Pony Centre in Exmoor and the Pigeon House Equestrian Centre in Oxfordshire. By starting the sampling process from the most recent growth at the follicle, the sampling date becomes a chronological marker, temporally fixing the first sample within a sequential set of data points extending for one year or longer, depending on the length of each individual hair. The samples were analysed for oxygen isotope values using an IRMS coupled within a Sercon HTEA. Preliminary results show a latitudinal gradient is evident on comparison between the locations, consistent with the findings of Darling and Talbot's study of fresh water isotopes in the British Isles (2003). These results support the hypothesis, showing that a study of oxygen isotope ratios within horse hair from Oxfordshire to Iceland showing a latitudinal depletion gradient, consistent with a depletion of oxygen isotope ratios due to decreasing temperatures. Darling, W. and Talbot, J. (2003). The O and H stable isotope composition of freshwaters in the British Isles. 1. Rainfall. Hydrol. Earth System Science, 7(2), pp.163-181.

  4. Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

    Directory of Open Access Journals (Sweden)

    Hannah B Vander Zanden

    2016-03-01

    Full Text Available The measurement of stable carbon (δ13C and nitrogen (δ15N isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H and oxygen (δ18O isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applications using δ2H and, to a lesser extent, δ18O values have demonstrated potential for these elements to provide novel insights in modern food web studies. We explore the advantages and challenges associated with three applications of δ2H and δ18O values in food web studies. First, large δ2H differences between aquatic and terrestrial ecosystem end members can permit the quantification of energy inputs and nutrient fluxes between these two sources, with potential applications for determining allochthonous vs. autochthonous nutrient sources in freshwater systems and relative aquatic habitat utilization by terrestrial organisms. Next, some studies have identified a relationship between δ2H values and trophic position, which suggests that this marker may serve as a trophic indicator, in addition to the more commonly used δ15N values. Finally, coupled measurements of δ2H and δ18O values are increasing as a result of reduced analytical challenges to measure both simultaneously and may provide additional ecological information over single element measurements. In some organisms, the isotopic ratios of these two elements are tightly coupled, whereas the isotopic disequilibrium in other organisms may offer insight into the diet and physiology of individuals. Although a coherent framework for interpreting δ2H and δ18O data in the context of food web studies is emerging, many fundamental uncertainties remain. We highlight directions for targeted research that

  5. Isotope study in geothermal fields in Java Island

    International Nuclear Information System (INIS)

    Wandowo, Z.A.

    1995-01-01

    Study in two geothermal fields, Dieng and Kamojang, in Java island by utilizing isotope technique has been carried out. Isotopic data of wells, springs and other geothermal manifestations providing informations on the recharge area of precipitation contributed to geothermal resources, flow paths and origin of geothermal fluids. The data of oxygen shift has also provided information on the characteristic the fields. (author). 8 refs, 5 figs, 3 tabs

  6. Measurement of environmental tritium for isotope hydrology studies

    International Nuclear Information System (INIS)

    1973-01-01

    The Section of Isotope Hydrology of the IAEA Division of Research and Laboratories gains valuable hydrological information from studies of the concentration of environmental tritium in precipitation, surface and groundwater samples from various sites around the world. This photo story shows the steps in the measurement of these very low levels of tritium in water as performed in the Isotope Hydrology Laboratory of the Agency. (author)

  7. The status of applying stable isotope in the studies of environmental science

    International Nuclear Information System (INIS)

    Bai Zhipeng; Zhang Liwen; Zhu Tan; Feng Yinchang

    2007-01-01

    The stable isotope composition is characteristic in the pollution source, and it is relatively fixed in the process of transferring and reaction. At present the precise analysis result of stable isotope ratio can be obtained easily. So the stable isotopes can be applied to the pollution affair arbitration and source study. The concept and analytical method of stable isotopes are introduced. The research status of the stable isotopes in the field of environmental science and the isotope fractionation is reviewed. (authors)

  8. Hyperpolarized C-13 MRS Cardiac Metabolism Studies in Pigs

    DEFF Research Database (Denmark)

    Giovannetti, G.; Hartwig, V.; Frijia, F.

    2012-01-01

    Cardiac metabolism assessment with hyperpolarized 13C magnetic resonance spectroscopy in pig models requires the design of dedicated coils capable of providing large field of view with high signal-to-noise ratio (SNR) data. This work presents a comparison between a commercial 13C quadrature...

  9. Proceedings of the study of environmental change using isotope techniques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-10-01

    Global warming is acknowledged as a major crisis facing society today, principally due to anticipated impacts on the environment, and availability and distribution of water resources. Scientific understanding of recent human-induced climate change, as well as evaluation of potential mitigation strategies, is progressively being developed through studies of atmospheric greenhouse gases and modern water energy carbon cycling processes. These efforts have been advanced through study of past global climate changes to understand mechanisms that play a role in determining natural climate fluctuations observed in ice cores, lake and sea sediments, corals, paleo-groundwater, cave deposits, tree rings, and other archives. Predictive models incorporating natural and human-induced climate change processes contribute to a better appreciation for the sensitivity of climate to specific anthropogenic perturbations. Increasingly, isotopes are being integrated in climate change studies. For example, isotope methodologies offer substantial improvements in the ability to label the origin and fate of greenhouse gases, and for studying the water and carbon cycle response to past climate changes, a high priority area for action identified by the Intergovernmental Panel on Climate Change (IPCC). Isotopes are also widely used as diagnostic variables for validation of models aimed at providing a prognosis of future environmental conditions. The International Atomic Energy Agency (IAEA) has long supported research and development of isotope applications for climate studies. The joint IAEA/WMO Global Network for Isotopes in Precipitation managed by the IAEA has for the last four decades provided the basic isotope data necessary for integrating stable oxygen and hydrogen isotopes in climate models. The IAEA has also sponsored co-ordinated research projects on Isotope Variations of Carbon Dioxide and other Trace Gases in the Atmosphere and Isotope-Aided Studies of Atmospheric Carbon Dioxide

  10. Proceedings of the study of environmental change using isotope techniques

    International Nuclear Information System (INIS)

    2002-01-01

    Global warming is acknowledged as a major crisis facing society today, principally due to anticipated impacts on the environment, and availability and distribution of water resources. Scientific understanding of recent human-induced climate change, as well as evaluation of potential mitigation strategies, is progressively being developed through studies of atmospheric greenhouse gases and modern water energy carbon cycling processes. These efforts have been advanced through study of past global climate changes to understand mechanisms that play a role in determining natural climate fluctuations observed in ice cores, lake and sea sediments, corals, paleo-groundwater, cave deposits, tree rings, and other archives. Predictive models incorporating natural and human-induced climate change processes contribute to a better appreciation for the sensitivity of climate to specific anthropogenic perturbations. Increasingly, isotopes are being integrated in climate change studies. For example, isotope methodologies offer substantial improvements in the ability to label the origin and fate of greenhouse gases, and for studying the water and carbon cycle response to past climate changes, a high priority area for action identified by the Intergovernmental Panel on Climate Change (IPCC). Isotopes are also widely used as diagnostic variables for validation of models aimed at providing a prognosis of future environmental conditions. The International Atomic Energy Agency (IAEA) has long supported research and development of isotope applications for climate studies. The joint IAEA/WMO Global Network for Isotopes in Precipitation managed by the IAEA has for the last four decades provided the basic isotope data necessary for integrating stable oxygen and hydrogen isotopes in climate models. The IAEA has also sponsored co-ordinated research projects on Isotope Variations of Carbon Dioxide and other Trace Gases in the Atmosphere and Isotope-Aided Studies of Atmospheric Carbon Dioxide

  11. Stable isotope studies: Progress report, March 1985--August 1987

    International Nuclear Information System (INIS)

    Ishida, Takanobu.

    1987-01-01

    Studies have been carried out in the following areas: Stable Isotope Fractionation (1) Effects of chemical poisons and surface modifiers on polycrystalline platinum electrode surfaces have been investigated with a goal to develop a new form of heterogeneous catalyst for the hydrogen isotope exchange between dihydrogen and water. (2) A new nitrogen-15 fractionation process has been developed, based on the isotope exchange between liquid N 2 O 3 -N 2 O 4 mixture and their vapor phase at a subambient temperature and a raised pressure. (3) A closed chemical recycle process has been developed for use in connection with the refluxer in the Nitrox-type nitrogen-15 plant. Isotope Effects (1) The vapor pressure isotope effect (VPIE) study of liquid fluoromethanes have been completed. (2) The VPIE study of solid and liquid ammonia has been completed. (3) A theoretical foundation of the additivity for the vibrational zero-point energy (ZPE) has been developed. Studies of Liquid Ammonia. With an aim to study intermolecular interaction (and the inversion phenomenon, in particular) in liquid ammonia, and to further investigate various ammonia solutions, a molecular dynamics (MD) study has been initiated. An MD program has been completed, and force field functions have been developed for an ensemble of non-rigid ammonia molecules. 107 refs., 41 figs., 10 tabs

  12. The essential role of isotopes in studies of water resources

    International Nuclear Information System (INIS)

    1977-01-01

    In studies of surface water, isotope techniques are used to measure water runoff from rain and snow, flow rates of streams and rivers, leakage from lakes, reservoirs and canals and the dynamics of various bodies of water. Studies of groundwater resources (springs, wells) today are virtually unthinkable without isotope techniques. Basically, these techniques are simple and relatively quick. Among the many questions which may be asked of hydrologists about a given groundwater supply, often the most critical one concerns the safe yield so that the source will not run dry, or for a source to be 'mined', the total yield. Isotope techniques can be used to solve such problems as: identification of the origin of groundwater, determination of its age, flow velocity and direction, interrelations between surface waters and ground waters, possible connections between different aquifers, local porosity, transmissivity and dispersivity of an aquifer. The cost of such investigations is often small in comparison to the cost of classical hydrological techniques, and in addition they are able to provide information which sometimes cannot be obtained by other techniques. The IAEA provides assistance to countries in the application of isotope techniques in water resources studies and other hydrology field projects. The examples given of field studies are intended to give some idea of how these techniques are being applied to specific problems in various regions of the world. Most are discussed briefly, but in some cases a more detailed description has been given in order to demonstrate the application of environmental isotope techniques

  13. Nitrogen and Oxygen Isotopic Studies of the Marine Nitrogen Cycle.

    Science.gov (United States)

    Casciotti, Karen L

    2016-01-01

    The marine nitrogen cycle is a complex web of microbially mediated reactions that control the inventory, distribution, and speciation of nitrogen in the marine environment. Because nitrogen is a major nutrient that is required by all life, its availability can control biological productivity and ecosystem structure in both surface and deep-ocean communities. Stable isotopes of nitrogen and oxygen in nitrate and nitrite have provided new insights into the rates and distributions of marine nitrogen cycle processes, especially when analyzed in combination with numerical simulations of ocean circulation and biogeochemistry. This review highlights the insights gained from dual-isotope studies applied at regional to global scales and their incorporation into oceanic biogeochemical models. These studies represent significant new advances in the use of isotopic measurements to understand the modern nitrogen cycle, with implications for the study of past ocean productivity, oxygenation, and nutrient status.

  14. Rapid Stable Isotope Turnover of Larval Fish in a Lake Superior Coastal Wetland: Implications for Diet and Life History Studies

    Science.gov (United States)

    Trophic linkages of larval fish in Lake Superior coastal wetlands, rivers and embayments can be identified using naturally occurring differences in the stable isotope ratios of nitrogen (15N:14N, ?15N) and carbon (13C:12C, ?13C). We sampled pelagic fish larvae weekly during sprin...

  15. Oxygen isotopic signature of CO2 from combustion processes

    NARCIS (Netherlands)

    Schumacher, M.; Werner, R. A.; Meijer, H. A. J.; Brand, W. A.; Geilmann, H.; Neubert, R. E. M.; Kaiser, J.; Jansen, Henk G.

    2011-01-01

    For a comprehensive understanding of the global carbon cycle precise knowledge of all processes is necessary. Stable isotope (C-13 and O-18) abundances provide information for the qualification and the quantification of the diverse source and sink processes. This study focuses on the delta O-18

  16. Progress in isotope hydrological study at Olak Lempit, Selangor

    International Nuclear Information System (INIS)

    Md Shahid Ayub

    2002-01-01

    This case study ia an on going project. Initial results from environmental isotopes and CFCs suggested short circuit to the groundwater flow. Removal of confining layer (if any) by mining activities could be the cause. It is also suggested the existence of saltwater / fresh water interface at the south-western fringe of the study area. This study is not yet conclusive. (Author)

  17. Isotope techniques in the study of environmental change

    International Nuclear Information System (INIS)

    1998-01-01

    The International Atomic Energy Agency, among its efforts to promote the wider use of isotope techniques in hydrology and related environmental disciplines, organized an International Symposium on Applications of Isotope Techniques in Studying Past and Current Environmental Changes in the Hydrosphere and the Atmosphere, held in 1993 in Vienna. The broad scientific interest and abundant participation in the symposium, as well as the rapid progress seen in this field since then, encouraged the IAEA to organize a second symposium of this kind. It was held from 14 to 18 April 1997 in Vienna and brought together 177 scientists representing 46 Member States, UNESCO, FAO, WMO, the World Climate Research Programme (WCRP) and the International Geosphere-Biosphere Programme (IGBP). The symposium was structured in five sessions of oral presentations, a poster session and a round table discussion that focused on trends and future requirements in isotope hydrology and on applications in climate and environmental research. The major themes covered by the presentations included the use of isotopic tracers in studies of atmospheric and hydrospheric changes and of the human impact on water and the environment. Special emphasis was placed on isotopic archives of climatic and environmental change. Some contributions addressed new technical approaches

  18. Isotope and hydrogeochemical studies of southern Jiangxi geothermal systems, China

    International Nuclear Information System (INIS)

    Zhou Wenbin; Li Xueli; Shi Weijun; Sun Zhanxue

    1999-01-01

    Southern Jiangxi is a geothermally active region, especially in Hengjing area. According to the work plan of IAEA Regional Collaboration in the Development of Geothermal Energy Resources and Environment Management through Isotope Techniques in East Asia and the Pacific (RAS-8-075), field investigation was carried out in Hengjing, southern Jiangxi Province, to demonstrate the use of isotope and geochemical techniques in low to medium temperature geothermal system. During the field investigation, 19 samples were taken from cold springs, hot springs and surface water in the area to determine their hydrochemical and gas compositions, hydrogen, oxygen, carbon and helium isotopes. The results of the study have shown that the geothermal waters in the studying region are of the same characteristics with the local meteoric water in oxygen and hydrogen isotope composition, indicating the geothermal waters are mainly derived from the local precipitation, while the gas composition and carbon and helium isotopes reveal that some gases in the geothermal waters have mantle origin. (author)

  19. Isotope analytics for the evaluation of the feeding influence on the isotope ratio in beef samples

    International Nuclear Information System (INIS)

    Herwig, Nadine

    2010-01-01

    Information about the origin of food and associated production systems has a high significance for food control. An extremely promising approach to obtain such information is the determination of isotope ratios of different elements. In this study the correlation of the isotope ratios C-13/C-12, N-15/N-14, Mg-25/Mg-24, and Sr-87/Sr-86 in bovine samples (milk and urine) and the corresponding isotope ratios in feed was investigated. It was shown that in the bovine samples all four isotope ratios correlate with the isotope composition of the feed. The isotope ratios of strontium and magnesium have the advantage that they directly reflect the isotope ratios of the ingested feed since there is no isotope fractionation in the bovine organism which is in contrast to the case of carbon and nitrogen isotope ratios. From the present feeding study it is evident, that a feed change leads to a significant change in the delta C-13 values in milk and urine within 10 days already. For the deltaN-15 values the feed change was only visible in the bovine urine after 49 days. Investigations of cows from two different regions (Berlin/Germany and Goestling/Austria) kept at different feeding regimes revealed no differences in the N-15/N-14 and Mg-26/Mg-24 isotope ratios. The strongest correlation between the isotope ratio of the bovine samples and the kind of ingested feed was observed for the carbon isotope ratio. With this ratio even smallest differences in the feed composition were traceable in the bovine samples. Since different regions usually coincide with different feeding regimes, carbon isotope ratios can be used to distinguish bovine samples from different regions if the delta C-13 values of the ingested feed are different. Furthermore, the determination of strontium isotope ratios revealed significant differences between bovine and feed samples of Berlin and Goestling due to the different geologic realities. Hence the carbon and strontium isotope ratios allow the best

  20. Stable isotopes in plant nutrition, soil fertility and environmental studies

    International Nuclear Information System (INIS)

    1991-01-01

    The individual contributions in these proceedings are indexed separately. Main topics covered include the measurement of biological nitrogen fixation, studies of soil organic matter, investigations of nutrient uptake and use by plants, studies of plant metabolism and new methodologies in the analysis of stable isotopes. Refs, figs and tabs

  1. Rubidium-strontium and uranium-lead isotopic age studies

    International Nuclear Information System (INIS)

    Loveridge, W.D.

    1981-01-01

    The results of five Rb-Sr isotopic age studies predominantly on whole-rock samples, and six U-Pb studies on zircon monazite concentrates are presented. Descriptions of the geological problems and interpretations of the measured ages are included. Laboratory age determination methods and techniques are described or referenced

  2. Fourier spectroscopy of the 12C2, 13C2, and 12C13C (0-0) swan bands

    International Nuclear Information System (INIS)

    Amiot, C.

    1983-01-01

    The (0-0) band of the C 2 Swan electronic system d 3 Pi/sub g/→a 3 Pi/sub u/ has been recorded by Fourier spectroscopy. The three isotopes species 12 C 2 , 13 C 2 , and 12 C 13 C were investigated. The observed wavenumbers were reduced to molecular parameters using a nonlinear least-square fitting procedure. Well-known perturbations at N' = 47 and N' = 51 again observed in the e 12 C 2 d 3 Pi/sub g/ (v = 0) level. Perturbations of the same kind are present in the 13 C 2 spectrum at N' = 34 and N' = 44,48,52. The 12 C 13 C spectrum exhibits in the observed spectral range a unique perturbation for N' = 41

  3. Structure of potassium isotopes studied with collinear laser spectroscopy

    CERN Document Server

    AUTHOR|(CDS)2082445

    By exploring the structure of different nuclei, one can learn about the interaction between the nucleons, their building blocks. In this field of research, there is a strong interplay between experiment and theory. In particular, theory has a crucial role in the interpretation of the experimental results, while new experimental results provide testing ground and directions for theorists. In the light- and mid-mass regions of the nuclear chart, the shell model is very successful and widely used for calculations of the ground- as well as excited- states properties. It is based on associated larger energy gaps between single particle energy levels for isotopes with certain proton (Z) and neutron (N) numbers, which are called "magic numbers". It was believed that these numbers (8, 20, 28, ...) are preserved for all nuclei throughout the nuclear chart. However, during the last decades studies of the isotopes with an unbalanced number of protons and neutrons revealed that in these isotopes the shell gaps could chan...

  4. Bibliographical study on photochemical separation of uranium isotopes

    International Nuclear Information System (INIS)

    Bougon, Roland

    1975-01-01

    The objective of this report is to propose an overview of knowledge and current works on isotopic separation of uranium by means of selective excitation where this excitation is obtained by a light source with a wave length corresponding to a selective or preferential absorption by a molecule or by the atom itself of one of the isotopes. After a brief overview of principles and requirements of isotopic separation by selective excitation, the author reviews compounds which can be used for this process. These compounds are mainly considered in terms of spectroscopy, and the study focuses on the most volatile among them, the uranium hexafluoride, its spectra, and possible processes for extraction. Some much less volatile uranium compounds are also mentioned with, when available, their spectroscopic properties. The uranium vapour excitation process is described, and some orientations for further researches are proposed [fr

  5. Study on the meat isotopic composition for origin identification

    Directory of Open Access Journals (Sweden)

    Irina Chernukha

    2018-03-01

    Full Text Available Russian consumer and governmental authorities are equally concerned to know where food products come from. This requires more accurate and specialized methods for the evaluation of geographical location. The following methods are used: chemometrics, histological and histochemical, genomic and proteomic, microbiological, immunochemical and mass spectrometric. Method of stable isotope analysis is becoming increasingly promising nowadays for the identification of meat and meat products' place of origin. The isotope ratios of the four elements - carbon, nitrogen, oxygen and hydrogen, are mainly determined. The method is successfully used to identify a country of origin of wines, juices and water. The aim of the research was to study the stable isotope ratios for pork and beef samples purchased in Moscow supermarkets (Russian Federation. The country of production of meat samples was determined according to specifications and/or labels. The geography of countries of meat samples origin includes Europe, both America continents and Australia. Databases collected by the All-Russian Scientific Research Institute of the Brewing, Non-Alcoholic and Wine Industrywere used for the analysis and interpretation of the results. Values of 13С/12С, δ13С, 18О/16О, δ18О, 2Н/1Н, δ2Н for 30 pork and beef samples from 13 countries were obtained. Differences in stable isotope ratios were found depending on place of origin. The data correlated with the oxygen isotope characteristics for wine, which were in the range from 2.5 to 4.5 ppm. According to the 13С/12С, δ13С results, the assumption was made about a false indication of the region for the beef sample. Despite the fact that beef was labeled as a product of Lithuania, the region of origin was most probably defined as Germany. The studies carried out showed the possibility to identify the region of raw meat origin by the stable isotope ratio.

  6. The Enriched Background Isotope Study (EBIS)

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Paul J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Trumbore, Susan [Univ. of California, Irvine, CA (United States); Swanston, Chris [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Torn, Margaret [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jastrow, Julie [Argonne National Lab. (ANL), Argonne, IL (United States); Parton, William A [Colorado State Univ., Fort Collins, CO (United States); Century Ecosystems, Inc. (United States); Post, Wilfred M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Froberg, Mats J [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hainsworth, Laura J [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kleber, Markus [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kramer, Christiane [Univ. of California, Irvine, CA (United States); Matamala-Paradeda, Roser [Argonne National Lab. (ANL), Argonne, IL (United States); Garten, Jr, Charles T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2007-02-05

    A unique, large release of radiocarbon occurred near the Oak Ridge Reservation (ORR), Oak Ridge, TN in July/August 1999. Measurements of 14C in tree ring cellulose throughout the ORR area demonstrate that the 1999 release was unprecedented in its uptake by vegetation. We are taking advantage of the whole-ecosystem isotopic label generated by this release to address five outstanding issues in the terrestrial carbon cycle: (1) partitioning of soil respiration between autotrophic and heterotrophic sources, and quantification of that partitioning seasonally and inter-annually, (2) partitioning of heterotrophic respiration sources between above-ground litter decomposition and below-ground root detritus decomposition, (3) identification of pathways leading from leaf and root detritus to long-term stabilization of soil organic matter, including the role of soil fauna, (4) the role of dissolved organic carbon (DOC) transport in distributing carbon within the soil profile, and, (5) the longevity and turnover time of fine roots. The first four issues are being addressed through a reciprocal litter transplant experiment set up at four sites on the ORR encompassing two soil types and two levels of 14C exposure in 1999. The fifth issue, longevity and turnover of fine roots, is being addressed by tracing the radiocarbon label through the fine root pool over time. With a combination of incubation, soil surface chamber and soil CO2 profiles, and continuous measurements of soil temperature and moisture controls, we are tracking changes in soil respiration partitioning over several years. The nature and source of organic matter pools that reside in soils for years to decades are being tracked with differently labeled root and surface litter, and experiments to exclude soil fauna have been initiated to elucidate their role in vertical transport. Periodic sampling of soils and soil solutions and the use of inert tracers, allow us to investigate the chemical nature and form of DOC and

  7. Experimental study of xenon isotopes production by gas centrifuge

    International Nuclear Information System (INIS)

    Zhou Mingsheng; Liang Xiongwen; Zhang Yonggang; Dong Jinping

    2006-01-01

    The gas centrifuge technology is studied for the separation of Xe isotopes. The nature Xe is chosen as processing gas. A four-state cascade is designed to separate 124 Xe to a concentration of being greater than 65% in three separation runs. 124 Xe can be enriched to a concentration 99% in more separation runs using a cascade of more gas centrifuges. (authors)

  8. Applications of DNA-Stable Isotope Probing in Bioremediation Studies

    Science.gov (United States)

    Chen, Yin; Vohra, Jyotsna; Murrell, J. Colin

    DNA-stable isotope probing, a method to identify active microorganisms without the prerequisite of cultivation, has been widely applied in the study of microorganisms involved in the degradation of environmental pollutants. Recent advances and technique considerations in applying DNA-SIP in bioremediation are highlighted. A detailed protocol of a DNA-SIP experiment is provided.

  9. Gas cleaning with hot char beds studied by stable isotopes

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Ahrenfeldt, Jesper; Ambus, Per

    2014-01-01

    The chemistry taking place in a high temperature char bed used for binding aromatic tar compounds has been studied in detail. 13C labelled tar compounds were used to trace the incorporation into the char bed using isotope ratio mass spectrometry (IRMS) and GC-MS. Furthermore, compounds labelled...

  10. Maximization of yield of C-13 isotope by multiphoton dissociation of ...

    Indian Academy of Sciences (India)

    pinhole and computing the far field intensity distributions using FFT (Fast Fourier. Transform) qualitatively .... Another advantage of using lines towards red edge is related to linear absorption coefficient. ..... J. Quantum Electron. 16 1086. 20.

  11. 40 CFR 721.6505 - Polymers of C13C15 oxoalcohol ethoxolates.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymers of C13C15 oxoalcohol... Specific Chemical Substances § 721.6505 Polymers of C13C15 oxoalcohol ethoxolates. (a) Chemical substance... polymers of C13C15 oxoalcohol ethoxolates (PMNs P-96-950/951) are subject to reporting under this section...

  12. 26 CFR 1.381(c)(13)-1 - Involuntary conversions.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Involuntary conversions. 1.381(c)(13)-1 Section 1.381(c)(13)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Insolvency Reorganizations § 1.381(c)(13)-1 Involuntary conversions...

  13. Isotopic hydrological studies carried out on the Karst water system

    International Nuclear Information System (INIS)

    Longinelli, A.

    1988-03-01

    The isotopic composition and temperature of many karst springs in the area of Trieste (Italy) have been measured for about three and a half years. During the same period the isotopic composition of precipitation has also been systematically studied. The isotopic composition of springs generally shows variations which are markedly shifted in time with respect to those of precipitation. In most of the springs the heavy isotope contents of winter samples are the highest of the whole year. On the contrary, summer samples normally show quite negative δ-values, the most negative of which often refer to the last summer months. The data obtained are explained in terms of variable mixing of waters from two main reservoirs. The less negative reservoir (in terms of δ) is recharged by ''local'' meteoric waters falling on the westernmost section of the karst area whose mean elevation is about 400 m a.s.l. The most negative reservoir is probably recharged by meteoric waters falling on the Slovenian section of the karst, whose mean elevation is about 800-900 m a.s.l. At least in the case of some of the northernmost karst springs, it is likely that a third water system, basically fed by the Isonzo river, flowing north of the karst area, could interfere with the previously mentioned reservoirs, partially controlling the outflow of some springs. 6 figs

  14. Stable isotope composition of atmospheric carbon monoxide. A modelling study

    International Nuclear Information System (INIS)

    Gromov, Sergey S.

    2014-01-01

    This study aims at an improved understanding of the stable carbon and oxygen isotope composition of the carbon monoxide (CO) in the global atmosphere by means of numerical simulations. At first, a new kinetic chemistry tagging technique for the most complete parameterisation of isotope effects has been introduced into the Modular Earth Submodel System (MESSy) framework. Incorporated into the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model, an explicit treatment of the isotope effects on the global scale is now possible. The expanded model system has been applied to simulate the chemical system containing up to five isotopologues of all carbon- and oxygen-bearing species, which ultimately determine the δ 13 C, δ 18 O and Δ 17 O isotopic signatures of atmospheric CO. As model input, a new stable isotope-inclusive emission inventory for the relevant trace gases has been compiled. The uncertainties of the emission estimates and of the resulting simulated mixing and isotope ratios have been analysed. The simulated CO mixing and stable isotope ratios have been compared to in-situ measurements from ground-based observatories and from the civil-aircraft-mounted CARIBIC-1 measurement platform. The systematically underestimated 13 CO/ 12 CO ratios of earlier, simplified modelling studies can now be partly explained. The EMAC simulations do not support the inferences of those studies, which suggest for CO a reduced input of the highly depleted in 13 C methane oxidation source. In particular, a high average yield of 0.94 CO per reacted methane (CH 4 ) molecule is simulated in the troposphere, to a large extent due to the competition between the deposition and convective transport processes affecting the CH 4 to CO reaction chain intermediates. None of the other factors, assumed or disregarded in previous studies, however hypothesised to have the potential in enriching tropospheric CO in 13 C, were found significant when explicitly simulated. The

  15. Use of Isotopes for Studying Reaction Mechanisms

    Indian Academy of Sciences (India)

    their positions rapidly. This is especially true of carbocations and ... Several specific examples can be quoted. Ammonia is a ... All experimental studies on this system were ... rearrangement. Hence, the species will have a relatively simple 13C.

  16. C-13 NMR spectroscopy of plasma reduces interference of hypertriglyceridemia in the H-1 NMR detection of malignancy

    International Nuclear Information System (INIS)

    Fossell, E.T.; Hall, F.M.; McDonagh, J.

    1991-01-01

    The authors have previously described the application of water-suppressed proton nuclear magnetic resonance (H-1 NMR) spectroscopy of plasma for detection of malignancy. Subsequently, hypertriglyceridemia has been identified as a source of false positive results. Here is described a confirmatory, adjunctive technique -analysis of the carbon-13 (C-13) NMR spectrum of plasma- which also identifies the presence of malignancy but is not sensitive to the plasma triglyceride level. Blinded plasma samples from 480 normal donors and 208 patients scheduled for breast biopsy were analyzed by water-suppressed H-1 and C-13 NMR spectroscopy. Triglyceride levels were also measured. Among the normal donors, there were 38 individuals with hypertriglyceridemia of whom 18 had results consistent with malignancy by H-1 NMR spectroscopy. However, the C-13 technique reduced the apparent H-1 false positive rate from 7.0 to 0.6 percent. Similarly, in the breast biopsy cohort, C-13 reduced the false positive rate from 2.8 to 0.9 percent. Furthermore, the accuracy of the combined H-1/C-13 test in this blinded study was greater than 96 percent in 208 patients studied. (author). 27 refs.; 5 figs.; 4 tabs

  17. Isotope techniques in lake water studies

    International Nuclear Information System (INIS)

    Gourcy, L.

    1999-01-01

    Freshwater lakes are among the most easily exploitable freshwater resources. Lakes are also recognized as major sedimentological features in which stored material can be used to study recent climate and pollution evolution. To adequately preserve these important landscape features, and to use them as climatic archives, an improved understanding of processes controlling their hydrologic and bio-geochemical environments if necessary. This article briefly describes the IAEA activities related to the study of lakes in such areas as lake budget, lake dynamics, water contamination, and paleolimnological investigations

  18. Three New Offset {delta}{sup 11}B Isotope Reference Materials for Environmental Boron Isotope Studies

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany); IsoAnalysis UG, Berlin (Germany); Vogl, J. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany)

    2013-07-15

    The isotopic composition of boron is a well established tool in various areas of science and industry. Boron isotope compositions are typically reported as {delta}{sup 11}B values which indicate the isotopic difference of a sample relative to the isotope reference material NIST SRM 951. A significant drawback of all of the available boron isotope reference materials is that none of them covers a natural boron isotope composition apart from NIST SRM 951. To fill this gap of required {delta}{sup 11}B reference materials three new solution boric acid reference materials were produced, which cover 60 per mille of the natural boron isotope variation (-20 to 40 per mille {delta}{sup 11}B) of about 100 per mille . The new reference materials are certified for their {delta}{sup 11}B values and are commercially available through European Reference Materials (http://www.erm-crm.org). The newly produced and certified boron isotope reference materials will allow straightforward method validation and quality control of boron isotope data. (author)

  19. Broadband non-selective excitation of plutonium isotopes for isotope ratio measurements in resonance ionization mass spectrometry: a theoretical study.

    Science.gov (United States)

    Sankari, M

    2012-10-15

    Making isotope ratio measurements with minimum isotope bias has always been a challenging task to mass spectrometrists, especially for the specific case of plutonium, owing to the strategic importance of the element. In order to use resonance ionization mass spectrometry (RIMS) as a tool for isotope ratio measurements, optimization of the various laser parameters and other atomic and system parameters is critical to minimize isotopic biases. Broadband simultaneous non-selective excitation of the isotopes of plutonium in the triple resonance excitation scheme with λ(1) = 420.77 nm, λ(2) = 847.28 nm, and λ(3) = 767.53 nm based on density matrix formalism has been theoretically computed for the determination of isotope ratios. The effects of the various laser parameters and other factors such as the atomization temperature and the dimensions of the atomic beam on the estimation of isotope ratios were studied. The effects of Doppler broadening, and time-dependent excitation parameters such as Rabi frequencies, ionization rate and the effect of non-Lorenztian lineshape have all been incorporated. The average laser powers and bandwidths for the three-excitation steps were evaluated for non-selective excitation. The laser intensity required to saturate the three-excitation steps were studied. The two-dimensional lineshape contour and its features were investigated, while the reversal of peak asymmetry of two-step and two-photon excitation peaks under these conditions is discussed. Optimized powers for the non-selective ionization of the three transitions were calculated as 545 mW, 150 mW and 545 mW and the laser bandwidth for all the three steps was ~20 GHz. The isotopic bias between the resonant and off-resonant isotope under the optimized conditions was no more than 9%, which is better than an earlier reported value. These optimized laser power and bandwidth conditions are better than in the earlier experimental work since these comprehensive calculations yield

  20. Isotopically modified nanoparticles for enhanced detection in bioaccumulation studies

    Science.gov (United States)

    Misra, S.K.; Dybowska, A.; Berhanu, D.; Croteau, M.-N.; Luoma, S.N.; Boccaccini, A.R.; Valsami-Jones, E.

    2012-01-01

    This work presents results on synthesis of isotopically enriched (99% 65Cu) copper oxide nanoparticles and its application in ecotoxicological studies. 65CuO nanoparticles were synthesized as spheres (7 nm) and rods (7 ?? 40 nm). Significant differences were observed between the reactivity and dissolution of spherical and rod shaped nanoparticles. The extreme sensitivity of the stable isotope tracing technique developed in this study allowed determining Cu uptake at exposure concentrations equivalent to background Cu concentrations in freshwater systems (0.2-30 ??g/L). Without a tracer, detection of newly accumulated Cu was impossible, even at exposure concentrations surpassing some of the most contaminated water systems (>1 mg/L). ?? 2011 American Chemical Society.

  1. Coulomb excitation of neutron-deficient polonium isotopes studied at ISOLDE

    CERN Document Server

    Neven, Michiel

    The polonium isotopes represent an interesting region of the nuclear chart having only two protons outside the Z = 82 closed shell. These isotopes have already been extensively studied theoretically and experimentally. The heavier isotopes (A > 200) seem to follow a "regular seniority-type regime" while for the lighter isotopes (A < 200) a more collective behavior is observed. Many questions remain regarding the transition between these two regimes and the configuration mixing between quantum states. Experiments in the lighter polonium isotopes point to the presence of shape coexistence, however the phenomenon is not fully understood. A Coulomb excitation study of the polonium isotopes whereby the dynamic properties are investigated can provide helpful insights in understanding the shape coexistence phenomena. In this thesis $^{202}$Po was studied via Coulomb excitation. The $^{202}$Po isotope was part of an experimental campaign in which the $^{196,198,200,206}$Po isotopes were studied as well via Coulomb...

  2. Applications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Lepoint, Gilles [Centre MARE, Laboratoire d' Oceanologie, Institut de Chimie, B6, Universite de Liege, B-4000 Liege (Belgium)]. E-mail: g.lepoint@ulg.ac.be; Dauby, Patrick [Centre MARE, Laboratoire d' Oceanologie, Institut de Chimie, B6, Universite de Liege, B-4000 Liege (Belgium); Institut Royal des Sciences Naturelles de Belgique, rue Vautier, B1000 Brussels (Belgium); Gobert, Sylvie [Centre MARE, Laboratoire d' Oceanologie, Institut de Chimie, B6, Universite de Liege, B-4000 Liege (Belgium)

    2004-12-01

    Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem.

  3. Isotopic studies of the aquiferous of Lima

    International Nuclear Information System (INIS)

    Plata, A.; Rojas M, R.; Sebastian C, C.; Ruiz G, J.

    1993-01-01

    Filtrations from Rimac and Blanco rivers and Graton Tunnel (on the Rimac basin, 80 km from Lima city and 2500 m sea level) were studied using artificial tracers and superficial tracers and superficial water analysis. Graton tunnel has a 3 -5 m 3 /s volume. Domestic and industrial demand of Lima (7 millions inhabitants) is 22 m 3 /s . Preliminary results suggest that Graton tunnel filtrations do not originate on Rimac or Blanco rivers, but in regions at 4600 m sea level. Detected tritium suggests that water filtrated in Graton tunnel is modern. (authors) 10 refs., 2 figs

  4. Nuclear transformations studies in selenium isotopes

    International Nuclear Information System (INIS)

    Lopez M, B.E.

    1976-01-01

    A compilation is made with regard to the chemical effects produced by nuclear transformations, such as the chemical effects of the beta decay and the chemical effects of the reaction (n,γ) in selenium radioisotopes. As a particular case the chemical effect of the isomeric transition of sup(81m)Se(VI) in potassium selenate crystals marked with radioactive selenium is studied experimentally and the method of adsorption in activated carbon is applied for the analytical separation of the traces of the nuclear isomer tetravalent sup(81b)Se(IV) of one fraction which contains the mixture of the selenium radioisotopes. (author)

  5. Recoveries of rat lymph FA after administration of specific structured C-13-TAG

    DEFF Research Database (Denmark)

    Vistisen, Bodil; Mu, Huiling; Høy, Carl-Erik

    2003-01-01

    of intragastrically administered L*L*L*, M*M*M*, ML*M, and ML*L* (where * = C-13-labeled FA) in rats. Lymph lipids were separated into lipid classes and analyzed by GC combustion isotope ratio MS. The recoveries of lymph TAG 18:2n-6 8 h after administration of L*L*L*, ML*M, and ML*L* were 38.6, 48.4, and 49...... rapid recovery of exogenous long-chain FA following administration of specific structured TAG compared with long-chain TAG was probably due to fast hydrolysis. The lymphatic recovery of 8:0 was 2.2% 24 h after administration of M*M*M*. This minor lymphatic recovery of exogenous 8:0 was probably due...... to low stimulation of chylomicron formation. These results demonstrate tendencies toward faster lymphatic recovery of long-chain FA after administration of specific structured TAG compared with long-chain TAG....

  6. Isotope ratio in stellar atmospheres and nucleosynthesis

    International Nuclear Information System (INIS)

    Barbuy, B.L.S.

    1987-01-01

    The determination of isotopic ratios in stellar atmospheres is studied. The isotopic shift of atomic and molecular lines of different species of a certain element is examined. CH and MgH lines are observed in order to obtain the 12 C: 13 C and 24 Mg: 25 Mg: 26 Mg isotpic ratios. The formation of lines in stellar atmospheres is computed and the resulting synthetic spectra are employed to determine the isotopic abundances. The results obtained for the isotopic ratios are compared to predictions of nucleosynthesis theories. Finally, the concept of primary and secondary element is discussed, and these definitions are applied to the observed variations in the abundance of elements as a function of metallicity. (author) [pt

  7. Australis: AMS for ultra sensitive trace element and isotopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Sie, S H; Suter, G F [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1994-12-31

    The accelerator mass spectrometer (AMS) at the CSIRO HIAF laboratory is being upgraded to enable in-situ measurements of ultratraces and isotopic-ratios in mineralogical applications. The upgraded system will include a microbeam Cs ion source which is designed to produce better than 50 micrometre diameter Cs beam to enable analyses of monomineralic grains. The Cs primary beam will be mass analysed in order to minimize contamination of the sample. The detection system will be upgraded to enable analyses of elements up to U, at 2 MV terminal voltage for charge states 4 and 5. The system will be known as AUSTRALIS: A.M.S. for Ultra Sensitive TRAce eLement and Isotopic Studies. An overview of the system and the anticipated applications in minerals exploration and mining research are presented. 4 refs., 1 fig.

  8. Australis: AMS for ultra sensitive trace element and isotopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1993-12-31

    The accelerator mass spectrometer (AMS) at the CSIRO HIAF laboratory is being upgraded to enable in-situ measurements of ultratraces and isotopic-ratios in mineralogical applications. The upgraded system will include a microbeam Cs ion source which is designed to produce better than 50 micrometre diameter Cs beam to enable analyses of monomineralic grains. The Cs primary beam will be mass analysed in order to minimize contamination of the sample. The detection system will be upgraded to enable analyses of elements up to U, at 2 MV terminal voltage for charge states 4 and 5. The system will be known as AUSTRALIS: A.M.S. for Ultra Sensitive TRAce eLement and Isotopic Studies. An overview of the system and the anticipated applications in minerals exploration and mining research are presented. 4 refs., 1 fig.

  9. Australis: AMS for ultra sensitive trace element and isotopic studies

    International Nuclear Information System (INIS)

    Sie, S.H.; Suter, G.F.

    1993-01-01

    The accelerator mass spectrometer (AMS) at the CSIRO HIAF laboratory is being upgraded to enable in-situ measurements of ultratraces and isotopic-ratios in mineralogical applications. The upgraded system will include a microbeam Cs ion source which is designed to produce better than 50 micrometre diameter Cs beam to enable analyses of monomineralic grains. The Cs primary beam will be mass analysed in order to minimize contamination of the sample. The detection system will be upgraded to enable analyses of elements up to U, at 2 MV terminal voltage for charge states 4 and 5. The system will be known as AUSTRALIS: A.M.S. for Ultra Sensitive TRAce eLement and Isotopic Studies. An overview of the system and the anticipated applications in minerals exploration and mining research are presented. 4 refs., 1 fig

  10. Isotopic Analysis of Fingernails as a USGS Open House Demonstration of the Use of Stable Isotopes in Foodweb Studies

    Science.gov (United States)

    Silva, S. R.; Kendall, C.; Young, M. B.; Choy, D.

    2011-12-01

    The USGS Isotope Tracers Project uses stable isotopes and tritium to add a unique dimension of chemical information to a wide range of environmental investigations. The use and application of isotopes is usually an unfamiliar and even esoteric topic to the general public. Therefore during three USGS open house events, as a public outreach effort, we demonstrated the use of stable isotopes by analyzing nitrogen and carbon isotopes from very small fragments of fingernail from willing participants. We titled the exhibit "You Are What You Eat". The results from all participants were plotted on a graph indicating the general influence of different food groups on the composition of body tissues as represented by fingernails. All participants were assigned a number and no personal-identification information was collected. A subset of participants provided us with an estimate of the number of days a week various foods were eaten and if they were vegetarians, vegans or non-vegetarians. Volunteers from our research group were on hand to explain and discuss fundamental concepts such as how foods attain their isotopic composition, the difference between C3 and C4 plants, the effects of assimilation, trophic enrichment, and the various uses of stable isotopes in environmental studies. The results of the fingernail analyses showed the variation of the range of isotopic compositions among about 400 people at each event, the distinct influence of C4 plants (mainly corn and cane sugar) on our carbon isotopic composition, and the isotopic differences between vegetarians and non vegetarians among other details (http://wwwrcamnl.wr.usgs.gov/isoig/projects/fingernails/). A poll of visitors attending the open house event in 2006 indicated that "You Are What You Eat" was among the most popular exhibits. Following the first two open house events we were contacted by a group of researchers from Brazil who had completed a very similar study. Our collaboration resulted in a publication in

  11. Synthetic Swan band profile of (1,0) of 12C12C and (0,0) of 12C12C and 12C13C in comets

    International Nuclear Information System (INIS)

    Swamy, K.S.K.

    1987-01-01

    The statistical equilibrium calculations of the 12 C 13 C molecule based on the resonance fluorescence process give similar results to those of the normal molecule. Therefore the assumption that the observed intensities of bands of the normal and the isotopic molecule differ only by their abundance ratio is reasonable. The synthetic profile of the (1,0) Swan band of 12 C 13 C (0,0) band of 12 C 12 C and 12 C 13 C have been calculated. The relative merits of using the rotational structure of the (1,0) or (0,0) band for the determination of the isotopic ratio 12 C/ 13 C is discussed briefly. (author)

  12. Experimental study of hydrogen isotopes storage on titanium bed

    International Nuclear Information System (INIS)

    Vasut, Felicia; Zamfirache, Marius; Bornea, Anisia; Pearsica, Claudia; Bidica, Nicolae

    2002-01-01

    As known, the Nuclear Power Plant Cernavoda equipped with a Canadian reactor, of CANDU type, is the most powerful tritium source from Europe. On long term, due to a 6·10 16 Bq/year, Cernavoda area will be contaminated due to the increasing tritium quantity. Also, the continuous contamination of heavy water from the reactor, induces a reduction of moderation's capacity. Therefore, one considers that it is improperly to use heavy water if its activity level is higher than 40 Ci/kg in the moderator and 2 Ci/kg in the cooling fluid. For these reasons, we have developed a detritiation technology, based on catalytic isotopic exchange and cryogenic distillation. Tritium will be removed from the tritiated heavy water, so it appears the necessity of storage of tritium in a special vessel that can provide a high level of protection and safety of environment and personal. There several metals were tested as storage beds for hydrogen isotopes. One of the reference materials used for storage of hydrogen isotopes is uranium, a material with a great storage capacity, but unfortunately it is a radioactive metal and also can react with the impurities from the stored gas. Other metals and alloys as ZrCo, Ti, FeTi are also adequate as storage beds at normal temperature. The paper presents studies about the reaction between hydrogen and titanium used as storage bed for the hydrogen isotopes resulted after the detritiation of tritiated heavy water. The experiments that were carried out used protium and mixture of deuterium and protium at different storage parameters as process gas. (authors)

  13. Water isotopes and the Eocene. A tectonic sensitivity study

    Science.gov (United States)

    Legrande, A. N.; Roberts, C. D.; Tripati, A.; Schmidt, G. A.

    2009-04-01

    The early Eocene (54 Million years ago) is one of the warmest periods in the last 65 Million years. Its climate is postulated to have been the result of enhanced greenhouse gas concentration, with CO2 roughly 4 times pre-industrial and methane 7 times pre-industrial concentrations. One interesting feature of this period to emerge recently is the intermittent presence of fossilized Azolla, a type of freshwater fern, in the Arctic Ocean. Synchronous (within dating error) with this appearance were major changes in the restriction of the Arctic Ocean and the other global oceans. We investigate this time period using the Goddard Institute for Space Studies ModelE-R, a fully coupled atmosphere-ocean general circulation model that incorporates water isotopes throughout the hydrologic cycle, making it an ideal model to test hypotheses of past climate change and to compare to paleoclimate proxy data. We assess the impact of tectonic variability by using minimal and maximal levels of restriction for the Arctic Ocean seaways. We find that the modulation of connectivity of these basins dramatically alters global salinity distribution, leading to large changes in ocean circulation. Greater restriction of the Arctic Basin is associated with fresh and relatively warmer conditions. The same mechanisms responsible for this redistribution of salt also change the global distribution of water isotopes, and can alias (water isotope) proxy climate signals of warmth.

  14. Use of stable isotope techniques in soil organic matter studies

    International Nuclear Information System (INIS)

    Gerzabek, M.H.

    1998-01-01

    Plants differ distinctly in their C-isotopic composition. The largest differences occur between plant species with different photosynthetic pathways. C 3 - and C 4 -plants are differentiated by approximately 1.4% on the δ-scale (approx. -2.7% 13 C versus -1.3% 13 C). Modern elemental analyser - mass spectrometer combinations reach accuracies of at least 0.01% δ 13 C. Therefore, the difference between C 3 and C 4 plants is sufficient to be used for tracer studies. Several investigations of soil organic mater (SOM) turnover under field conditions were undertaken using the fact that the vegetation cover changed between C 3 and C 4 plants. The discrimination between SOM originating from indigenous vegetation (forest, C 3 ) and sugar cane (C 4 ) after 50 years of cropping introducing two SOM compartments of different stability was described. Another example is the change from prairie vegetation (C 4 ) to different C 3 -crops and the evaluation of the carbon origin at or near equilibrium. More recent studies use 15 N-labelled C 4 -plant residues or 13 C-labelled C 3 -plants to elucidate the fate of carbon and nitrogen in soils developed under C 3 -vegetation. Both in situ experiments and laboratory incubations were used to evaluate carbon and nitrogen fluxes from crop residues. Physical fractionation of bulk soil into particle sizes proved to be of advantage to follow short and long-term dynamics of crop residues within SOM. Changes in the natural abundance of 13 C and 15 N within soil profiles can elucidate leaching or mineralization of humic substances. Changes in the natural abundance of stable isotopes are also possible due to the application of organic manures, quantification, however is not easy because of the small isotopic differences between soil and manure carbon and nitrogen. 15 N labelling of soil nitrogen has been widely used in the last two decades to quantify biological nitrogen fixation. Considerable progress has been made due to the isotope dilution

  15. Transport of C-13-labelled linoleic and C-13-labelled caprylic acid in rat plasma after administration of specific structured triacylglycerols

    DEFF Research Database (Denmark)

    Vistisen, Bodil; Høy, Carl-Erik

    2004-01-01

    the transport of dietary C-13-labelled fatty acids in rat plasma to compare the chylomicron fatty acid metabolism after administration of specific structured, long chain and medium chain triacylglycerols. Rats were fed ML*M, M*LM*, L*L*L* or M*M*M* (L=linoleic acid, 18:2n-6, M=caprylic acid, 8:0, * = C-13......-labelled fatty acid) by gavage. A maximum transport of 0.5% of the administered C-13-labelled 18:2n-6 was observed in 1mL rat plasma both after administration of L*L*L* and ML*M, while approximately 0.04% of the administered C-13-labelled 8:0 was detected in 1mL plasma following administration of M......*M*M* or M*LM*. After L*L*L* administration C-13-labelled 20:4n-6 was observed in plasma, probably formed by elongation and desaturation of 18:2n-6 in the enterocyte or liver cells. Furthermore, C-13-labelled 16:0, 48:0, 18: 1n-9 and 20:4n-6 were observed in plasma of rats fed M*M*M* and M*LM* due...

  16. Isotope study of groundwater in Beishan area, Gansu province

    International Nuclear Information System (INIS)

    Guo Yonghai; Liu Shufen; Yang Tianxiao

    2004-01-01

    Using the isotope techniques, the groundwater origin, evolution and circulation in the potential site of China's high-level waste repository are studied. The results indicate that both shallow groundwaters are and deep groundwaters in the site area are of meteoric origin. The shallow groundwaters are mainly recharged by modern and local precipitation, and the deep groundwaters are originated from regional history period with lower temperature. Through the study we can also understand that the deep underground is a very low-permeability system where the groundwater flow-rates are very low. (author)

  17. Contribution of isotopic data in cerebrospinal fluid (CSF) studies

    International Nuclear Information System (INIS)

    Askienazy, S.; Ducassou, D.

    The growing interest in isotopic CSF studies is explained by the fact that the mechanism and classification of hydrocephalus cases are based not only on anatomoclinical data but also on physiological information inaccessible by static image methods. This article shows the full importance of dynamic CSF research (ideal tracer: 111 In-DTPA); the possibilities of myeloscintigraphy to study the permeability of the medullary sub-arachnoid spaces (tracers used: sup(99m)Tc-DTPA in the liquid phase or xenon bubble technique in the gas phase); ventricular morphology; existence of meningeal gaps [fr

  18. Fundamental studies in isotope chemistry. Progress report, 1 July 1976--30 Jun 1977

    International Nuclear Information System (INIS)

    Bigeleisen, J.; Harris, T.H.

    1977-01-01

    The current thrust of the program is the use of isotope effects to study the fundamental properties of matter, measurement and calculation of isotope fractionation factors of systems of potential technological importance and the correlation of isotope effects with molecular structure. The first measurements of the isotopic fractionation factors for two components in a solution were completed by the study of argon-krypton mixtures. The measurements cover the range from pure argon to pure krypton and extrapolate very well to previous measurements on the pure components. The vapor pressure isotope effects between solid-vapor and liquid-vapor for the rare gases neon, argon, and krypton is given

  19. Use of Isotopes for Studying Reaction Mechanisms -RE ...

    Indian Academy of Sciences (India)

    can give even greater details of chemical processes. Isotopic substitution ... isotope effect (KIE) would depend on the location of the isotope with respect to ... magnitude of KIE is given by kH/ko. ... How can one explain these variations? Theory.

  20. Study of groundwater salinization in Chaj Doab using environmental isotopes

    International Nuclear Information System (INIS)

    Hussain, S.D.; Sajjid, M.I.; Akram, W.; Ahmad, M.; Rafiq, M.

    1991-09-01

    Environmental isotopes and chemical composition of water have been used to study the origin of groundwater salinity in Chaj Doab. Three important possible processes of salinization i.e. enrichment of salt content of water by evaopration, mixing with connate marine water and dissolution of salts from soil sediments have been investigated. No evidence for mixing with connate maine water could be found. The process of evaporation too does not seem to apply any significant role in salinization of groundwater. The dissolution of salts from soil sediments appears as dominant mechanism for increasing the salt content of water in this area. (author)

  1. Microscopic study of neutron-rich dysprosium isotopes

    International Nuclear Information System (INIS)

    Vargas, Carlos E.; Velazquez, Victor; Lerma, Sergio

    2013-01-01

    Microscopic studies in heavy nuclei are very scarce due to large valence spaces involved. This computational problem can be avoided by means of the use of symmetry-based models. Ground-state, γ and β bands, and their B(E2) transition strengths in 160-168 Dy isotopes, are studied in the framework of the pseudo-SU(3) model which includes the preserving symmetry Q . Q term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized. Additionally, three rotor-like terms are considered, whose free parameters, fixed for all members of the chain, are used to fine tune the moment of inertia of rotational bands and the band head of γ and β bands. The model succesfully describes in a systematic way rotational features in these nuclei and allows to extrapolate toward the midshell nucleus 170 Dy. The results presented show that it is possible to study a full chain of isotopes or isotones in the region with the present model. (orig.)

  2. Microscopic study of neutron-rich dysprosium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Carlos E. [Universidad Veracruzana, Facultad de Fisica e Inteligencia Artificial, Xalapa (Mexico); Universidad Nacional Autonoma de Mexico, Facultad de Ciencias, Apartado Postal 70-542, Mexico D.F. (Mexico); Velazquez, Victor [Universidad Nacional Autonoma de Mexico, Facultad de Ciencias, Apartado Postal 70-542, Mexico D.F. (Mexico); Lerma, Sergio [Universidad Veracruzana, Facultad de Fisica e Inteligencia Artificial, Xalapa (Mexico)

    2013-01-15

    Microscopic studies in heavy nuclei are very scarce due to large valence spaces involved. This computational problem can be avoided by means of the use of symmetry-based models. Ground-state, {gamma} and {beta} bands, and their B(E2) transition strengths in {sup 160-168}Dy isotopes, are studied in the framework of the pseudo-SU(3) model which includes the preserving symmetry Q . Q term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized. Additionally, three rotor-like terms are considered, whose free parameters, fixed for all members of the chain, are used to fine tune the moment of inertia of rotational bands and the band head of {gamma} and {beta} bands. The model succesfully describes in a systematic way rotational features in these nuclei and allows to extrapolate toward the midshell nucleus {sup 170}Dy. The results presented show that it is possible to study a full chain of isotopes or isotones in the region with the present model. (orig.)

  3. Utilizing Stable Isotopes and Isotopic Anomalies to Study Early Solar System Formation Processes

    Science.gov (United States)

    Simon, Justin

    2017-01-01

    Chondritic meteorites contain a diversity of particle components, i.e., chondrules and calcium-, aluminum-rich refractory inclusions (CAIs), that have survived since the formation of the Solar System. The chemical and isotopic compositions of these materials provide a record of the conditions present in the protoplanetary disk where they formed and can aid our understanding of the processes and reservoirs in which solids formed in the solar nebula, an important step leading to the accretion of planetesimals. Isotopic anomalies associated with nucleosynthetic processes are observed in these discrete materials, and can be compared to astronomical observations and astrophysical formation models of stars and more recently proplyds. The existence and size of these isotopic anomalies are typically thought to reflect a significant state of isotopic heterogeneity in the earliest Solar System, likely left over from molecular cloud heterogeneities on the grain scale, but some could also be due to late stellar injection. The homogenization of these isotopic anomalies towards planetary values can be used to track the efficiency and timescales of disk wide mixing,

  4. A lower limit on the surface C-12/C-13 ratio in Alpha Orionis

    Science.gov (United States)

    Gautier, T. N., III; Fink, U.; Larson, H. P.; Thompson, R. I.

    1976-01-01

    The second overtone CO bands near 1.6 microns were analyzed in Alpha Ori using synthetic spectra. No firm identification of (C-13)O was made, which allowed a lower limit of 20 to be set on the C-12/C-13 ratio. A rather low microturbulent velocity of 2 km/s was found to match the spectrum of Alpha Ori best.

  5. Sensitivity-enhanced C-13 MR spectroscopy of the human brain at 3 Tesla

    NARCIS (Netherlands)

    Klomp, D.W.J.; Renema, W.K.J.; Graaf, M. van der; Galan, B.E. de; Kentgens, A.P.M.; Heerschap, A.

    2006-01-01

    A new coil design for sensitivity-enhanced C-13 MR spectroscopy (MRS) of the human brain is presented. The design includes a quadrature transmit/receive head coil optimized for C-13 MR sensitivity. Loss-less blocking circuits inside the coil conductors allow this coil to be used inside a homogeneous

  6. 3D Hyperpolarized C-13 EPI with Calibrationless Parallel Imaging

    DEFF Research Database (Denmark)

    Gordon, Jeremy W.; Hansen, Rie Beck; Shin, Peter J.

    2018-01-01

    With the translation of metabolic MRI with hyperpolarized 13C agents into the clinic, imaging approaches will require large volumetric FOVs to support clinical applications. Parallel imaging techniques will be crucial to increasing volumetric scan coverage while minimizing RF requirements and tem...... strategies to accelerate and undersample hyperpolarized 13C data using 3D blipped EPI acquisitions and multichannel receive coils, and demonstrated its application in a human study of [1-13C]pyruvate metabolism....

  7. Isotope Effect on the Thermal Conductivity of Graphene

    Directory of Open Access Journals (Sweden)

    Hengji Zhang

    2010-01-01

    Full Text Available The thermal conductivity (TC of isolated graphene with different concentrations of isotope (C13 is studied with equilibrium molecular dynamics method at 300 K. In the limit of pure C12 or C13 graphene, TC of graphene in zigzag and armchair directions are ~630 W/mK and ~1000W/mK, respectively. We find that the TC of graphene can be maximally reduced by ~80%, in both armchair and zigzag directions, when a random distribution of C12 and C13 is assumed at different doping concentrations. Therefore, our simulation results suggest an effective way to tune the TC of graphene without changing its atomic and electronic structure, thus yielding a promising application for nanoelectronics and thermoelectricity of graphene-based nano device.

  8. Delayed Particle Study of Neutron Rich Lithium Isotopes

    CERN Multimedia

    Marechal, F; Perrot, F

    2002-01-01

    We propose to make a systematic complete coincidence study of $\\beta$-delayed particles from the decay of neutron-rich lithium isotopes. The lithium isotopes with A=9,10,11 have proven to contain a vast information on nuclear structure and especially on the formation of halo nuclei. A mapping of the $\\beta$-strength at high energies in the daughter nucleus will make possible a detailed test of our understanding of their structure. An essential step is the comparison of $\\beta$-strength patterns in $^{11}$Li and the core nucleus $^{9}$Li, another is the full characterization of the break-up processes following the $\\beta$-decay. To enable such a measurement of the full decay process we will use a highly segmented detection system where energy and emission angles of both charged and neutral particles are detected in coincidence and with high efficiency and accuracy. We ask for a total of 30 shifts (21 shifts for $^{11}$Li, 9 shifts $^{9}$Li adding 5 shifts for setting up with stable beam) using a Ta-foil target...

  9. Application of environmental isotopes to characterize landfill gases and leachate

    International Nuclear Information System (INIS)

    Liu, C.L.; Hackley, K.C.; Baker, J.

    1992-01-01

    Environmental isotopes have been used to help characterize landfill gases and leachate for the purpose of identifying leachate and/or gas contamination in surrounding monitoring wells. Carbon isotopes (C-13/C-12 and C-14), hydrogen isotopes (H-3 and H-2/H-1) and oxygen isotopes (O-18/O-16) were used to characterize methane, carbon dioxide and leachate produced from two municipal landfills in northeastern Illinois. The isotopic results from the landfill-derived gases and leachate are compared to isotopic compositions of groundwater and gases from nearby monitoring wells. C-14 activity of landfill CH 4 is high compared to CH 4 normally found in subsurface sediments. For this study C-14 activities of the landfill methane range from 129--140 PMC. The C-14 of the dissolved inorganic carbon (DIC) of the leachate samples also have relatively high activities, ranging from 126--141 PMC. The δC-13 and δD values for CH 4 from the landfills fall within a range of values representative of microbial methane produced by acetate-fermentation. The δC-13 of the CO 2 and the DIC are very positive, ranging from 8--14 per-thousand for CO 2 and 13--22 per-thousand for DIC. The δO-18 values of the leachates are similar to current meteoric water values, however, two of the leachate samples are significantly enriched in deuterium by approximately 65 per-thousand. Tritium values of the leachate water are generally higher than expected. For one landfill the tritium activity ranges from 227--338 TU, for the second landfill the tritium activity is approximately 1,300 TU. Compared to tritium levels in normal groundwater, these higher tritium values in the leachates indicate that this isotope has the potential to be an effective tracer for detecting leachate migration

  10. Raman spectroscopic studies of isotopic diatomic molecules and a technique for measuring stable isotope ratios using Raman scattering

    International Nuclear Information System (INIS)

    Harney, R.C.

    1976-01-01

    A method for measuring stable isotope ratios using Raman scattering has been developed. This method consists of simultaneously counting photons scattered out of a high-intensity laser beam by different isotopically-substituted molecules. A number of studies of isotopic diatomic molecules have been made. The Q-branches of the Raman spectra of the isotopic molecules 14 N 15 N and 16 O 18 O were observed at natural abundance in nitrogen and oxygen samples. Comparison of the ratios of the intensities of the Q-branches of the major nitrogen and oxygen isotopic molecules with mass spectrometric determinations of the isotopic compositions yielded scattering cross sections of 14 N 15 N relative to 14 N 14 N and 16 O 18 O relative to 16 O 16 O. These cross section ratios differ from unity, a difference which can be explained by considering nuclear mass effects on the Franck-Condon factors of the molecular transitions. The measured intensities of the 14 N 15 N and 16 O 18 O Q-branches provided the baseline data needed to make the previously-mentioned extrapolation. High-resolution (approximately 0.15 cm -1 ) spectra of the Q-branches of 14 N 14 N and 16 O 16 O yielded a direct determination of α/sub e/ (the difference between the rotational constant in the ground and first excited vibrational states) for these molecules. The measured values are in excellent agreement with those obtained by other means. Complete Raman spectra (pure rotation, rotation-vibration, and high-resolution Q-branch) were obtained on a sample of pure 18 O 18 O. Analysis of this data yielded the molecular parameters: the equilibrium internuclear separation r/sub e/, the moment of inertia I/sub e/, and the energy parameters α/sub e/, B/sub e/, and ΔG/sub 1 / 2 /. These are in good agreement with data obtained by microwave spectroscopy

  11. Isotope labeling for NMR studies of macromolecular structure and interactions

    International Nuclear Information System (INIS)

    Wright, P.E.

    1994-01-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform 13 C, 15 N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific 13 C and 15 N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions

  12. Use of isotopes in root activities and distribution studies

    International Nuclear Information System (INIS)

    Nario M, Adriana; Pino N, Ines; Albornoz G, Maria Paz; Baherle V, Pedro

    2003-01-01

    Several studies shown the relevance of the plant's root activity pattern knowledge, across the profile, to determine the suitable zone to apply the nutrients and irrigation to the plant. In Chile, the studies with the isotopes 15 N and 32 P had been used to carry out applications in solution across the soil profile and in lateral distances from the plant in fruit trees and prairies to determine root activity pattern. In peaches, under furrow irrigation, the major root concentration was found at 20 cm depth and 1 m lateral distance from the trunk. Table grapes, under drip irrigation, presented more root activity at 40 cm depth and under the dripper line in lateral distance. In prairies, the root activity was found between 10 to 40 cm depth, depending on the root capacity to explore the profile (author)

  13. Stable isotope studies. Progress report, March 1, 1985-October 1985

    International Nuclear Information System (INIS)

    Ishida, T.

    1985-01-01

    The studies of last year have been continued in three experimental and two theoretical areas. A closed recycle process for SO 2 /H 2 SO 4 has been developed. The phase ratios of the isotopic reduced partition function ratios for solid and liquid 14 NH 3 / 14 ND 3 and 14 NH 3 / 15 NH 3 and for 12 CH 2 F 2 / 12 CD 2 F 2 and 12 CH 2 F 2 / 13 CH 2 F 2 have been obtained from differential vapor pressure data, and F matrices for each phase of each chemical species have been calculated. A concept of combining chemically modified electrodes and supported catalysts has been investigated. Results of ab initio MO calculations on various clusters of methylene fluoride are compared to those on the clusters of methyl fluoride and fluoroform. An MO study on clusters of ammonia molecules has been started. 29 refs., 3 figs., 10 tabs

  14. Isotope labeling for NMR studies of macromolecular structure and interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.E. [Scripps Research Institute, La Jolla, CA (United States)

    1994-12-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform {sup 13}C, {sup 15}N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific {sup 13}C and {sup 15}N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions.

  15. The isotope altitude effect reflected in groundwater: a case study from Slovenia.

    Science.gov (United States)

    Mezga, Kim; Urbanc, Janko; Cerar, Sonja

    2014-01-01

    This paper presents the stable isotope data of oxygen (δ(18)O) and hydrogen (δ(2)H) in groundwater from 83 sampling locations in Slovenia and their interpretation. The isotopic composition of water was monitored over 3 years (2009-2011), and each location was sampled twice. New findings on the isotopic composition of sampled groundwater are presented, and the data are also compared to past studies regarding the isotopic composition of precipitation, surface water, and groundwater in Slovenia. This study comprises: (1) the general characteristics of the isotopic composition of oxygen and hydrogen in groundwater in Slovenia, (2) the spatial distribution of oxygen isotope composition (δ(18)O) and d-excess in groundwater, (3) the groundwater isotope altitude effect, (4) the correlation between groundwater d-excess and the recharge area altitude of the sampling location, (5) the relation between hydrogen and oxygen isotopes in groundwater in comparison to the global precipitation isotope data, (6) the groundwater isotope effect of distance from the sea, and (7) the estimated relation between the mean temperature of recharge area and δ(18)O in groundwater.

  16. Isotope Fractionation Studies in Prestellar Cores: The Case of Nitrogen

    Science.gov (United States)

    Milam, Stefanie N.; Charnley, Steven B.

    2011-01-01

    Isotopically fractionated material is found in many solar system objects, including meteorites and comets. It is considered, in some cases, to trace interstellar material that was incorporated into the solar system without undergoing significant processing, thus preserving the fractionation. In interstellar molecular clouds, ion-molecule chemistry continually cycles nitrogen between the two main reservoirs - N and N2 - leading to only minor N-15 enrichments. Charnley and Rodgers showed that depletion of CO removes oxygen from the gas and weakens this cycle such that significant N-15 fractionation can occur for N2 and other N-bearing species in such cores. Observations are being conducted at millimeter and submillimeter wavelengths employing various facilities in order to both spatially and spectrally, resolve emission from these cores. A preliminary study to obtain the N-14/N-15 ratio in nitriles (HCN and HNC) was conducted at the Arizona Radio Observatory's 12m telescope on Kitt Peak, AZ. Spectra were obtained at high resolution (0.08 km/s) in order to resolve dynamic properties of each source as well as to resolve hyperfine structure present in certain isotopologues. This study included four dark cloud cores, observed to have varying levels of molecular depletion: L1521E, L1498, L1544, and L1521F. Previous studies of the N-14/N-15 ratio towards LI544 were obtained with N2H+ and NIH3, yielding ratios of 446 and >700, respectively. The discrepancy observed in these two measurements suggests a strong chemical dependence on the fractionation of nitrogen. Ratios (C,N, and D) obtained from isotopologues for a particular molecule are likely tracing the same chemical heritage and are directly comparable within a given source. Results and comparisons between the protostellar evolutionary state and isomer isotope fractionation as well as between other N-bearing species will be presented.

  17. Decay studies of neutron-deficient lawrencium isotopes

    International Nuclear Information System (INIS)

    Antalic, S.; Saro, S.; Streicher, B.; Venhart, M.; Hessberger, F.P.; Ackermann, D.; Heinz, S.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R.; Hofmann, S.; Kuusiniemi, P.; Leino, M.; Nishio, K.; Sulignano, B.

    2008-01-01

    The radioactive decay of the isotopes 254-256 Lr and their daughter products was investigated by means of α, prompt α-γ and delayed conversion electron-γ coincidence spectroscopy. The isotopes were produced using the reaction 48 Ca+ 209 Bi. (orig.)

  18. Isotopic study of water origin in salt mines in Poland

    International Nuclear Information System (INIS)

    Dulinski, M.; Grabczak, J.; Garlicki, A.; Zuber, A.

    1998-01-01

    The most important results of isotopic analyses carried out so far in salt mines in Wieliczka, Bochnia, Klodawa, Wapno and Inowroclaw are presented. Discussion of these results for individual leakages proofs that isotopic methods are fully useful in determining of the origin of water appearing in salt mines. (author)

  19. Isotope study in the Alpine karst region of Rawil (Switzerland)

    International Nuclear Information System (INIS)

    Schotterer, U.; Siegenthaler, U.; Oeschger, H.; Wildberger, A.; Nabholz, W.

    1978-01-01

    An isotope study in the karst of the high Alps in Switzerland is described. From 1973 to 1978 discharge, 3 H, delta 18 O, conductivity and temperature were measured in representative springs. The springs are influenced by snowmelt in late spring and summer, by rain in late summer and autumn, and in the winter period, when infiltration stops, by reservoir water. Since tritium in precipitation in the last years scattered irregularly in time and space, the residence time of winter baseflow (2-4 years) could not be determined very precisely. The pronounced difference in delta 18 O between several springs allowed us to estimate the difference in mean altitude of their recharge areas. (orig.) [de

  20. Isotopes to Study the coastal aquifer plain, Cap Bon, Tunisia

    International Nuclear Information System (INIS)

    Ben Hamouda, M. F.; Zouari, Kamel; Tarhouni, J.; Gaye, C.B.; Oueslati, M.N.

    2005-01-01

    The study area is located in the northeastern part of Tunisia about 60 km south of the Tunis city. It is bounded by the Gulf of Haematite in the East, Djebel Sidi Aberahmane in the West, The town of Nabeul in the south and the area of the town Kelibia in the north. The landscape is a coastal plain slightly sloping (3%) towards the sea. The groundwater of the Oriental coast aquifer system occurs mainly at two levels, a shallow aquifer up to depths of about 50 m whose reservoir is consisted by sediments of the Plio quaternary and a deep aquifer between about 150 and 400 m located in the sand stone formations of Miocene of the anticline of Djebel Sidi Abderrahmene. The climate of the region is semi-arid to sub-humid and of Mediterranean type. There are no perennial rivers in this region; but intense storms occasionally cause surface runoff, which is discharged by the oueds. The study is related to a technical cooperation project with the International Atomic Energy Agency, Vienna, Austria, aimed at the use of isotope techniques to study the seawater intrusion into the coastal aquifers of Cap Bon in Tunisia. In this regard, a better understanding of the recharge and flow regime as well as the origin or salinity of the groundwater was required. To reach this goal, isotope and geochemical investigations were carried out. Water samples were taken from wells, boreholes from deep and shallow aquifer of the Oriental coastal aquifer located between Beni Khiar in the south and Kelibia in the north. The samples were analysed for their chemical and isotopic compositions (18O, 2H, 3H, 13C, 14C, 34S). In the following, the results of these analyses are presented and discussed in terms of the recharge and flow regime of the groundwater and the origin and evolution of its salinity. The results of geochemical and isotopic studies have shown that the groundwater is very eterogeneous and suggest the aquifer is replenished by recent water coming from direct infiltration from rain. At

  1. Coastal niches for terrestrial predators: a stable isotope study

    Energy Technology Data Exchange (ETDEWEB)

    Mellbrand, K.; Hamback, P.A., E-mail: peter.hamback@botan.su.se [Stockholm Univ., Dept. of Botany, Stockholm (Sweden)

    2010-12-15

    The purpose of this study was to identify the use of marine versus terrestrial food items by terrestrial arthropod predators on Baltic Sea shores. The inflow of marine nutrients in the area consists mainly of marine algal detritus and emerging aquatic insects (e.g., chironomids). Diets of coastal arthropods were examined using carbon and nitrogen stable isotope analysis in a two source mixing model. The results suggest that spiders are the terrestrial predators mainly utilizing nutrients and energy of marine origin on Baltic Sea shores, whereas insect predators such as beetles and heteropterans mainly utilize nutrients and energy derived from terrestrial sources, possibly owing to differences in hunting behaviour. That spiders are the predators which benefit the most from the marine inflow suggest that eventual effects of marine subsidies for the coastal ecosystem as a whole are likely mediated by spiders. (author)

  2. Groundwater salinity study in the Mekong Delta using isotope techniques

    International Nuclear Information System (INIS)

    Le Van Khoi, Nguyen Kien Chinh; Do Tien Hung

    2002-01-01

    Environmental isotopes D, 18 O and chemical composition were used for study of recharge and salinization of groundwater in the are located between Bassac and Mekong Rivers. The results showed that: (a) Pleistocene aquifers are recharged through flood plains and outcrops located at the same altitude. The sanility of groundwater in these aquifers is mostly due to dissolution of the aquifer material, (b) Pliocene and Miocene aquifers receive recharge through outcrops located at the higher altitude on the northeast extension of the Delta and Cambodia. The salinity of groundwater in the coastal region of the aquifer is attributable to sea water intrusion. There appears to be significant retention of sea water in the coastal sediment during intrusion. (Author)

  3. A study of Cirus heavy water system isotopic purity

    International Nuclear Information System (INIS)

    Thomas, Shibu; Sahu, A.K.; Unni, V.K.P.; Pant, R.C.

    2000-01-01

    Cirus uses heavy water as moderator and helium as cover gas. Approximately one tonne of heavy water was added to the system every year for routine make up. Isotopic purity (IP) of this water used for addition was always higher than that of the system. Though this should increase IP of heavy water in the system, it has remained almost at the same level, over the years. A study was carried out to estimate the extent of improvement in IP of heavy water in the system that should have occurred because of this and other factors in last 30 years. Reasons for non-occurrence of such an improvement were explored. Ion exchange resins used for purification of heavy water and air ingress into helium cover gas system appear to be the principal sources of entry of light water into heavy water system. (author)

  4. Coastal niches for terrestrial predators: a stable isotope study

    International Nuclear Information System (INIS)

    Mellbrand, K.; Hamback, P.A.

    2010-01-01

    The purpose of this study was to identify the use of marine versus terrestrial food items by terrestrial arthropod predators on Baltic Sea shores. The inflow of marine nutrients in the area consists mainly of marine algal detritus and emerging aquatic insects (e.g., chironomids). Diets of coastal arthropods were examined using carbon and nitrogen stable isotope analysis in a two source mixing model. The results suggest that spiders are the terrestrial predators mainly utilizing nutrients and energy of marine origin on Baltic Sea shores, whereas insect predators such as beetles and heteropterans mainly utilize nutrients and energy derived from terrestrial sources, possibly owing to differences in hunting behaviour. That spiders are the predators which benefit the most from the marine inflow suggest that eventual effects of marine subsidies for the coastal ecosystem as a whole are likely mediated by spiders. (author)

  5. Study of isotopic exchange reactions of azidothymidine with tritium

    International Nuclear Information System (INIS)

    Sidorov, G.V.; Zverkov, Yu.B.; Myasoedov, N.F.

    2003-01-01

    Different reactions of isotopic exchange of azidothymidine (3 - azido-3 - desoxythymidine) with tritium, such as solid- and liquid-phase catalytic isotopic exchange with gaseous tritium and isotopic exchange in solution with tritium water, are investigated. It is determined that catalytic reactions of azidothymidine with gaseous tritium in solution lead to practically full reduction of azido group up to amino group. In reactions of solid-phase catalytic hydrogenation this process takes place too and 3 - azido-3 - desoxythymidine yield is from 20 to 70 %. Molar radioactivity of labelled with tritium azidothymidine prepared in reactions of solid-phase catalytic isotopic exchange with gaseous tritium and so by isotopic exchange in solution with tritium water does not exceed 0.5 Cu/mmol [ru

  6. Carbon and oxygen isotopic composition of coal and carbon dioxide derived from laboratory coal combustion: A preliminary study

    Science.gov (United States)

    Warwick, Peter D.; Ruppert, Leslie F.

    2016-01-01

    The concentration of carbon dioxide (CO2) in the atmosphere has dramatically increased from the start of the industrial revolution in the mid-1700s to present levels exceeding 400 ppm. Carbon dioxide derived from fossil fuel combustion is a greenhouse gas and a major contributor to on-going climate change. Carbon and oxygen stable isotope geochemistry is a useful tool to help model and predict the contributions of anthropogenic sources of CO2 in the global carbon cycle. Surprisingly few studies have addressed the carbon and oxygen isotopic composition of CO2 derived from coal combustion. The goal of this study is to document the relationships between the carbon and oxygen isotope signatures of coal and signatures of the CO2 produced from laboratory coal combustion in atmospheric conditions.Six coal samples were selected that represent various geologic ages (Carboniferous to Tertiary) and coal ranks (lignite to bituminous). Duplicate splits of the six coal samples were ignited and partially combusted in the laboratory at atmospheric conditions. The resulting coal-combustion gases were collected and the molecular composition of the collected gases and isotopic analyses of δ13C of CO2, δ13C of CH4, and δ18O of CO2 were analysed by a commercial laboratory. Splits (~ 1 g) of the un-combusted dried ground coal samples were analyzed for δ13C and δ18O by the U.S. Geological Survey Reston Stable Isotope Laboratory.The major findings of this preliminary work indicate that the isotopic signatures of δ13C (relative to the Vienna Pee Dee Belemnite scale, VPDB) of CO2 resulting from coal combustion are similar to the δ13CVPDB signature of the bulk coal (− 28.46 to − 23.86 ‰) and are not similar to atmospheric δ13CVPDB of CO2 (~ − 8 ‰, see http://www.esrl.noaa.gov/gmd/outreach/isotopes/c13tellsus.html). The δ18O values of bulk coal are strongly correlated to the coal dry ash yields and appear to have little or no influence on the δ18O values of CO2

  7. Study on atmospheric hydrogen enrichment by cryopump method and isotope separation by gas chromatography

    International Nuclear Information System (INIS)

    Taniyama, Yuki; Momoshima, Noriyuki

    2001-01-01

    To obtain the information of source of atmospheric hydrogen tritium an analysis of tritium isotopes is thought to be effective. So an atmospheric hydrogen enrichment apparatus and a cryogenic gas chromatographic column were made. Experiments were carried out to study the performance of cryopump to enrich atmospheric hydrogen and the column to separate hydrogen isotopes that obtained by cryopump method. The cryopump was able to process about 1000 1 atmosphere and the column was able to separate hydrogen isotopes with good resolution. (author)

  8. Isotope analytics for the evaluation of the feeding influence on the isotope ratio in beef samples; Isotopenanalytik zur Bestimmung des Einflusses der Ernaehrung auf die Isotopenzusammensetzung in Rinderproben

    Energy Technology Data Exchange (ETDEWEB)

    Herwig, Nadine

    2010-11-17

    Information about the origin of food and associated production systems has a high significance for food control. An extremely promising approach to obtain such information is the determination of isotope ratios of different elements. In this study the correlation of the isotope ratios C-13/C-12, N-15/N-14, Mg-25/Mg-24, and Sr-87/Sr-86 in bovine samples (milk and urine) and the corresponding isotope ratios in feed was investigated. It was shown that in the bovine samples all four isotope ratios correlate with the isotope composition of the feed. The isotope ratios of strontium and magnesium have the advantage that they directly reflect the isotope ratios of the ingested feed since there is no isotope fractionation in the bovine organism which is in contrast to the case of carbon and nitrogen isotope ratios. From the present feeding study it is evident, that a feed change leads to a significant change in the delta C-13 values in milk and urine within 10 days already. For the deltaN-15 values the feed change was only visible in the bovine urine after 49 days. Investigations of cows from two different regions (Berlin/Germany and Goestling/Austria) kept at different feeding regimes revealed no differences in the N-15/N-14 and Mg-26/Mg-24 isotope ratios. The strongest correlation between the isotope ratio of the bovine samples and the kind of ingested feed was observed for the carbon isotope ratio. With this ratio even smallest differences in the feed composition were traceable in the bovine samples. Since different regions usually coincide with different feeding regimes, carbon isotope ratios can be used to distinguish bovine samples from different regions if the delta C-13 values of the ingested feed are different. Furthermore, the determination of strontium isotope ratios revealed significant differences between bovine and feed samples of Berlin and Goestling due to the different geologic realities. Hence the carbon and strontium isotope ratios allow the best

  9. Water stable isotopes: application to the water cycle and climate variations study

    International Nuclear Information System (INIS)

    Risi, C.

    2009-12-01

    The stable isotopic composition of water (H 2 16 , HDO, H 2 18 , H 2 17 ) is a promising tracer of the present day water cycle and past climates. While the isotopic composition recorded in polar ice core have long been used to reconstruct past temperatures, however, what controls the isotopic composition of the tropical precipitation is more complex. The goal of this thesis is thus to better understand the processes that affect the isotopic composition of tropical precipitation and atmospheric water, more particularly in the tropics. Since most of the tropical precipitation arises from atmospheric convection, and most isotopic archives are on land, we focus more particularly on the impact of convective and land surface processes. In turn, what can be learned about convection and land surface processes using isotopic measurements? Can they help constrain their representation in models? At the inter-annual to climate change scale, what information about the tropical climate variability is recorded in isotopic signals observed in archives? First, we investigate the influence of convection on water stable isotopes. We use both (1) numerical modeling, with a hierarchy of models (single column model, two-dimensional model of squall lines, general circulation model) and (2) data analysis, using isotopic data from rain collected in the Sahel during the African Monsoon Multidisciplinary Analysis campaign, at the event and intra-event scales. These studies highlight the strong impact of convection on the precipitation composition, and stress the importance of rain evaporation and convective or meso-scale subsidence in controlling the rain isotopic composition. Convection also plays an important role on isotopic profiles in the upper troposphere-lower stratosphere. Second, we study what information about climatic variability is recorded by water stable isotopes in precipitation. We analyze simulations of present day and past climates with LMDZ, and evaluate to what extent

  10. APPLICATION OF A C-13 NMR TOPOLOGICAL MODEL TO THE STRUCTURE ELUCIDATION OF ORGANIC COMPOUNDS

    Institute of Scientific and Technical Information of China (English)

    袁身刚; 彭琛; 郑崇直

    1992-01-01

    This paper presents an approach which can elucidate automatically the structures of simple organic compounds from their C-13 NMR spectral data by using a computer. Based on a substructure/C-13 NMR chemical shift topological correlation model, the approach deduces the candidate substructures and the constraints for the substructure assembling from the molecular formula and C-13 NMR spectral data. Then, candidate structures are generated under these constraints by assembling the candidate substructures in a partial superposition manner. Candidate substructures or structures are evaluated once they are generated in order to eliminate those conflicting with the original data as early as possible. The evaluation of a (sub)structure is mainly carried out by simulating its C-13 NMR (sub) spectrum, which is again based on the model, and comparing the simulated spectrum with the original data.

  11. Nuclear structure studies of rare francium isotopes using Collinear Resonance Ionization Spectroscopy (CRIS)

    CERN Document Server

    AUTHOR|(CDS)2084441

    It was known for many years that nuclei possessing certain numbers of protons (Z) and neutrons (N), called the magic numbers (8,20,28,50,82,126...), exhibit characteristic behavior and are in general more stable than their neighboring isotopes. As the capabilities of producing isotopes with more extreme values of Z and N increased, it was realized that those spherical nuclei only represent a small fraction of the total number of isotopes and that most isotopes are deformed. In order to study exotic isotopes and their deformation, it was necessary to develop new experimental techniques that would be powerful enough to be able to cope with very small production yields, but precise enough to measure the nuclear properties (such as radii and moments) with relatively small uncertainties. One technique that can measure nuclear properties of scarcely produced isotopes is in-source resonant ionization, but this technique does not allow for sufficient precision to deduce nuclear quadrupole moments. Furthermore, this t...

  12. Isotope tracers in global water and climate studies of the past and present

    International Nuclear Information System (INIS)

    Edwards, T.W.D.; Birks, S.J.; Gibson, J.J.

    2002-01-01

    To date the global distribution of isotopes in modern precipitation has been characterized almost exclusively from the IAEA/WMO GNIP database, although patchiness of GNIP station records in both time and space has limited the potential of isotope hydrology and climate applications in some areas. Herein, we discuss the prospect of utilizing GCMs for simulating global isotope distributions as a supplementary tool for modern and paleoclimate isotope studies to bridge this gap. Such models currently generate reliable zonal isotope fields, and it is anticipated that future enhancements in finescale resolution of GCMs, and incorporation of land-surface feedbacks and topography will allow for future development of a global reanalysis data set ground-truthed by GNIP. Compilation of time-slice maps of past isotope distribution in precipitation from archival records of meteoric waters also offers significant potential to ground-truth paleoclimate simulations extending back tens to hundreds of thousands of years. (author)

  13. Stable carbon isotope signals in particulate organic and inorganic carbon of coccolithophores - A numerical model study for Emiliania huxleyi.

    Science.gov (United States)

    Holtz, Lena-Maria; Wolf-Gladrow, Dieter; Thoms, Silke

    2017-05-07

    A recent numerical cell model, which explains observed light and carbonate system effects on particulate organic and inorganic carbon (POC and PIC) production rates under the assumption of internal pH homeostasis, is extended for stable carbon isotopes ( 12 C, 13 C). Aim of the present study is to mechanistically understand the stable carbon isotopic fractionation signal (ε) in POC and PIC and furthermore the vital effect(s) included in measured ε PIC values. The virtual cell is divided into four compartments, for each of which the 12 C as well as the 13 C carbonate system kinetics are implemented. The compartments are connected to each other via trans-membrane fluxes. In contrast to existing carbon fractionation models, the presented model calculates the disequilibrium state for both carbonate systems and for each compartment. It furthermore calculates POC and PIC production rates as well as ε POC and ε PIC as a function of given light conditions and the compositions of the external carbonate system. Measured POC and PIC production rates as well as ε PIC values are reproduced well by the model (comparison with literature data). The observed light effect on ε POC (increase of ε POC with increasing light intensities), however, is not reproduced by the basic model set-up, which is solely based on RubisCO fractionation. When extending the latter set-up by assuming that biological fractionation includes further carbon fractionation steps besides the one of RubisCO, the observed light effect on ε POC is also reproduced. By means of the extended model version, four different vital effects that superimpose each other in a real cell can be detected. Finally, we discuss potential limitations of the ε PIC proxy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Isotopic studies of Yucca Mountain soil fluids and carbonate pedogenesis

    International Nuclear Information System (INIS)

    McConnaughey, T.A.; Whelan, J.F.; Wickland, K.P.; Moscati, R.J.

    1994-01-01

    Secondary carbonates occurring within the soils, faults, and subsurface fractures of Yucca Mountain contain some of the best available records of paleoclimate and palehydrology for the potential radioactive waste repository site. This article discusses conceptual and analytical advances being made with regard to the interpretation of stable isotope data from pedogenic carbonates, specifically related to the 13 C content of soil CO 2 , CaCO 3 , precipitation mechanisms, and isotopic fractionations between parent fluids and precipitating carbonates. The 13 C content of soil carbon dioxide from Yucca Mountain and vicinity shows most of the usual patterns expected in such contexts: Decreasing 13 C content with depth decreasing 13 C with altitude and reduced 13 C during spring. These patterns exist within the domain of a noisy data set; soil and vegetational heterogeneities, weather, and other factors apparently contribute to isotopic variability in the system. Several soil calcification mechanisms appear to be important, involving characteristic physical and chemical environments and isotopic fractionations. When CO 2 loss from thin soil solutions is an important driving factor, carbonates may contain excess heavy isotopes, compared to equilibrium precipitation with soil fluids. When root calcification serves as a proton generator for plant absorption of soil nutrients, heavy isotope deficiencies are likely. Successive cycles of dissolution and reprecipitation mix and redistribute pedogenic carbonates, and tend to isotopically homogenize and equilibrate pedogenic carbonates with soil fluids

  15. Lead Diversification through a Prins-Driven Macrocyclization Strategy: Application to C13-Diversified Bryostatin Analogues.

    Science.gov (United States)

    Wender, Paul A; Billingsley, Kelvin L

    2013-01-01

    The design, synthesis, and biological evaluation of a novel class of C13-diversified bryostatin analogues are described. An innovative and general strategy based on a Prins macrocyclization-nucleophilic trapping cascade was used to achieve late-stage diversification. In vitro analysis of selected library members revealed that modification at the C13 position of the bryostatin scaffold can be used as a diversification handle to regulate biological activity.

  16. CARBON ISOTOPE FRACTIONATION IN PROTOPLANETARY DISKS

    International Nuclear Information System (INIS)

    Woods, Paul M.; Willacy, Karen

    2009-01-01

    We investigate the gas-phase and grain-surface chemistry in the inner 30 AU of a typical protoplanetary disk (PPD) using a new model which calculates the gas temperature by solving the gas heating and cooling balance and which has an improved treatment of the UV radiation field. We discuss inner-disk chemistry in general, obtaining excellent agreement with recent observations which have probed the material in the inner regions of PPDs. We also apply our model to study the isotopic fractionation of carbon. Results show that the fractionation ratio, 12 C/ 13 C, of the system varies with radius and height in the disk. Different behavior is seen in the fractionation of different species. We compare our results with 12 C/ 13 C ratios in the solar system comets, and find a stark contrast, indicative of reprocessing.

  17. Structure of Li, Be And B isotopes studied with quantum molecular dynamic model

    International Nuclear Information System (INIS)

    Abdel-Hafiez, A.; Saleh, Z.A.

    2000-01-01

    Quantum molecular dynamics (QMD) is applied to study the ground state properties of Li, Be and B isotopes. The model Hamiltonian includes both two-and three-body density dependent interactions, a Coulomb term, and a momentum dependent Pauli potential. With parameters which guarantee the infinite nuclear matter properties, the QMD model can only reproduce the binding energies for Be and B isotopes. The experimental root mean square radii of the Li, Be and B isotopes are not sufficiently reproduced by these parameters. It is shown, however, that the binding energies and root mean square radii of these isotopes can simultaneously be reproduced in the lower density limit of the potential parameters

  18. Study ω and φ photoproduction in the nucleon isotopic channels

    International Nuclear Information System (INIS)

    Zhao, Q.

    2002-01-01

    We present results for the photoproduction of ω and φ meson in the nucleon isotopic channels. A recently developed quark model with an effective Lagrangian is employed to account for the non-diffractive s- and u-channel processes; the diffractive feature arising from the natural parity exchange is accounted for by the t-channel pomeron exchange, while the unnatural parity exchange is accounted for by the t-channel pion exchange. In the ω production, the isotopic effects could provide more information concerning the search of 'missing resonances', while in the φ production, the isotopic effects could highlight non-diffractive resonance excitation mechanisms at large angles. (author)

  19. Uranium isotopic effect studies on cation and anion exchange resins

    International Nuclear Information System (INIS)

    Sarpal, S.K.; Gupta, A.R.

    1975-01-01

    Uranium isotope effects in exchange reactions involving hexavalent and tetravalent uranium, on ion exchange resins, have been re-examined. The earlier work on uranium isotope effects in electron exchange reactions involving hexavalent and tetravalent uranium, has been critically reviewed. New experimental data on these systems in hydrochloric acid medium, has been obtained, using break-through technique on anion-exchange columns. The isotope effects in these break-through experiments have been reinterpreted in a way which is consistent with the anion exchange behaviour of the various uranium species in these systems. (author)

  20. A first isotopic dietary study of the Greenlandic Thule Culture

    DEFF Research Database (Denmark)

    Nelson, D.E.; Lynnerup, Niels; Arneborg, J.

    2012-01-01

    The isotopic dietary method has been applied to samples of some 65 Thule Culture individuals from existing archaeological collections of Greenlandic human skeletal material. The aim was to use the Greenlandic Thule Culture as a test of the isotopic method, in that we know they were heavily...... was used as the basis for analysis. As expected, the results indicate that these people were almost entirely dependent on the marine biosphere for their protein. An exception is those from Northeast Greenland, whose isotopic signatures show evidence for consumption of terrestrial protein as well....... Not expected were the observed differences at the regional and local levels....

  1. Stable carbon and oxygen isotope study on benthic foraminifera ...

    Indian Academy of Sciences (India)

    Ajoy K Bhaumik

    2017-07-24

    Jul 24, 2017 ... of a species for isotopic analysis has forced us to select multiple species from down-core samples. Thus ... microhabitat, climatic variability, bottom and pore ...... Trends, rhythms, and aberrations in global climate 65 Ma.

  2. Triple Isotope Water Analyzer for Extraplanetary Studies, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research (LGR) proposes to employ Off-Axis ICOS to develop triple-isotope water analyzers for lunar and other extraplanetary exploration. This instrument...

  3. Isotopic study of some fossil and actual hydrothermal systems

    International Nuclear Information System (INIS)

    Demont, J.M.

    1981-07-01

    Oxygen and hydrogen isotopic compositions of rocks from the INAG no 1 drillhole provide evidence of a fossil hydrothermal system in the Ceyssat region of the Massif Central. Oxygen isotope temperatures for the mineral paragenesis are about 275 0 C and the water is of marine origin. Measurements have also been made of delta 13 C values of dissolved carbon and gaseous CO 2 from several hot springs in the Pyrenees and Massif Central. The carbon isotopic composition of the total systems have been calculated from the gas-liquid ratios at the emergence sites and these results are discussed in terms of the origin of the carbon. Most of the hydrothermal carbon is of deep origin. The observed variations in isotopic compositions may be explained by the behavior of the fluids during their ascent to the surface [fr

  4. Coordinated Isotopic and TEM Studies of Presolar Graphites from Murchison

    Science.gov (United States)

    Croat, T. K.; Stadermann, F. J.; Zinner, E.; Bernatowicz, T. J.

    2004-03-01

    TEM and NanoSIMS investigations of the same presolar Murchison KFC graphites revealed high Zr, Mo, and Ru content in refractory carbides within the graphites. Along with isotopically light carbon, these suggest a low-metallicity AGB source.

  5. Surface Nb-ALLOYING on 0.4C-13Cr Stainless Steel: Microstructure and Tribological Behavior

    Science.gov (United States)

    Yu, Shengwang; You, Kai; Liu, Xiaozhen; Zhang, Yihui; Wang, Zhenxia; Liu, Xiaoping

    2016-02-01

    0.4C-13Cr stainless steel was alloyed with niobium using double glow plasma surface alloying and tribological properties of Nb-alloyed steel such as hardness, friction and wear were measured. Effects of the alloying temperature on microstructure and the tribological behavior of the alloyed steel were investigated compared with untreated steel. Formation mechanisms of Nb-alloyed layers and increased wear resistance were also studied. The result shows that after surface Nb-alloying treatment, the 0.4C-13Cr steel exhibits a diffusion adhesion at the alloyed layer/substrate interface and improved tribological property. The friction coefficient of Nb-alloyed steel is decreased by about 0.3-0.45 and the wear rate after Nb-alloying is only 2-5% of untreated steel.

  6. Isotopic studies of nitrogen balance in a cracking clay

    International Nuclear Information System (INIS)

    Craswell, E.T.; Martin, A.E.

    1975-01-01

    The stable isotope 15 N was used to study the fate of nitrogen fertilizers applied to a black earth growing wheat. In a glasshouse experiment using soil packed at 56 per cent moisture (pF 2) into pots, added nitrate was almost completely recovered (mean, 98.8 +- 2.3 per cent) by soil and plant analysis. This experiment was repeated using 15 N-labelled ammonium as well as nitrate; mean recoveries at 15 weeks were 96.8 and 97 per cent respectively (+- 2.2 per cent at P 15 N measured, 97 and 96.8 per cent at 56 and 63 per cent moisture respectively. Fallow and planted systems were then studied in a gas lysimeter. During experiments lasting up to 14 weeks, gaseous losses as 15 N-labelled denitrification products were less than the equivalent of 0.2 μg nitrogen/g soil (the lower limit of detection with a mass spectrometer). Although analysis of plant and soil from the lysimeter in two experiments showed virtually quantitative recovery (99.7 and 97.05 per cent), small (0.16 per cent) losses of labelled ammonia into the lysimeter atmosphere were detected. The significance of these results is discussed in relation to the common finding of large deficits in nitrogen balance studies. (author)

  7. On depth profiling of hydrogen and helium isotopes and its application to ion-implantation studies

    International Nuclear Information System (INIS)

    Boettiger, J.

    1979-01-01

    The thesis is divided into two parts, the first being a general review of the experimental methods for depth profiling of light isotopes, where ion beams are used. In the second part, studies of ion implantation of hydrogen and helium isotopes, applying the techniques discussed in the first part, are described. The paper summarizes recent experimental results and discusses recent developments. (Auth.)

  8. Advisory group meeting on stable isotope labelled compounds in biomedical studies

    International Nuclear Information System (INIS)

    Vera Ruiz, H.; Parr, R.M.

    1985-11-01

    The programme of the meeting was restricted to topics involving applications of stable isotopes of the lighter elements (H, C, N, O). The current status of stable isotope techniques and applications in nutritional and biomedical studies, the applicability of these techniques in developing countries and the IAEA's future programmes on this topic were discussed

  9. Contribution of stable isotopes to the study of pharmacokinetics of magnesium salts

    International Nuclear Information System (INIS)

    Benech, H.

    1999-01-01

    The use of stable isotopes as labels is becoming an attractive tool for the study of magnesium behavior in humans. It has been used two stable isotopes of magnesium, 25 Mg and 26 Mg, to measure the absolute bioavailability of a pharmaceutical form of magnesium. (N.C.)

  10. Multi-column chromatography and the use of isotopes in the study of steroid metabolism

    International Nuclear Information System (INIS)

    Sayegh, J.F.; Vestergaard, P.

    1978-01-01

    Multi-column liquid chromatography is demonstrated to be a technique well suited for isotope experiments involving administration of labelled cortisol. It has potential for secretion rate determinations, for dynamic studies of cortisol metabolism and for work with stable isotopes. (author)

  11. Stable isotope studies. Progress report, August 1, 1974--July 31, 1975

    International Nuclear Information System (INIS)

    Flynn, G.W.; Hsu, D.S.Y.; Preses, J.M.; Spindel, W.; Weston, R.E.

    1975-01-01

    Progress is reported in the following studies: selective two-step laser-induced photodissociation, unimolecular processes induced by multiple-photon absorption, and vibrational energy transfer processes involving isotopic species of sulfur dioxide. These laser-induced chemical reactions can possibly be applied to isotope separation

  12. Applications of isotopes

    International Nuclear Information System (INIS)

    Kirby-Smith, J.S.

    1976-01-01

    Current and potential applications of stable isotopes as tracers in a number of biomedical and environmental areas are discussed. It is pointed out that a wide variety of problems exist in these fields whose solutions in principle are amenable to the isotopic approach. The number and diversity of these problems as well as the unique role stable isotopes can play in their solution illustrate the importance of achieving and maintaining a broad inventory of isotopic species. Experience has demonstrated unequivocally an additional overriding requirement for widespread exploration of stable isotopes by the scientific and technical community, i.e., the need for low cost availability of the materials in quantity. Some representative applications of 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, and 18 O are discussed

  13. Application of carbon and oxygen stable isotopes to the study of Brazilian precambrian

    International Nuclear Information System (INIS)

    Torquato, J.R.F.

    1980-01-01

    Samples of carbonated rocks of precambrian age are studied. The stable carbon and oxygen isotopes are applied to the study of terrestrial materials considering the variations of some element isotopic composition in function of the environment of sedimentation. The isotopic analysis was done using mass spectrometers. The analytical results and the description of region geology of the site of each sample are presented. The isotopic data are interpreted aiming to the environment of sedimentation. New techniques for better improvement of carbon and oxygen ratios, are proposed, such as: to use the analysis of surface trend and the isotopic logging in mapping of surface and subsurface. A new method for approximated determination of the ages of precambrian carbonated rocks, considering the limitations of their new technique, is also presented. (M.C.K.) [pt

  14. Isotope pattern deconvolution as a tool to study iron metabolism in plants.

    Science.gov (United States)

    Rodríguez-Castrillón, José Angel; Moldovan, Mariella; García Alonso, J Ignacio; Lucena, Juan José; García-Tomé, Maria Luisa; Hernández-Apaolaza, Lourdes

    2008-01-01

    Isotope pattern deconvolution is a mathematical technique for isolating distinct isotope signatures from mixtures of natural abundance and enriched tracers. In iron metabolism studies measurement of all four isotopes of the element by high-resolution multicollector or collision cell ICP-MS allows the determination of the tracer/tracee ratio with simultaneous internal mass bias correction and lower uncertainties. This technique was applied here for the first time to study iron uptake by cucumber plants using 57Fe-enriched iron chelates of the o,o and o,p isomers of ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA) and ethylenediamine tetraacetic acid (EDTA). Samples of root, stem, leaves, and xylem sap, after exposure of the cucumber plants to the mentioned 57Fe chelates, were collected, dried, and digested using nitric acid. The isotopic composition of iron in the samples was measured by ICP-MS using a high-resolution multicollector instrument. Mass bias correction was computed using both a natural abundance iron standard and by internal correction using isotope pattern deconvolution. It was observed that, for plants with low 57Fe enrichment, isotope pattern deconvolution provided lower tracer/tracee ratio uncertainties than the traditional method applying external mass bias correction. The total amount of the element in the plants was determined by isotope dilution analysis, using a collision cell quadrupole ICP-MS instrument, after addition of 57Fe or natural abundance Fe in a known amount which depended on the isotopic composition of the sample.

  15. Isotope pattern deconvolution as a tool to study iron metabolism in plants

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Castrillon, Jose A.; Moldovan, Mariella; Garcia Alonso, J.I. [University of Oviedo, Department of Physical and Analytical Chemistry, Oviedo (Spain); Lucena, Juan J.; Garcia-Tome, Maria L.; Hernandez-Apaolaza, Lourdes [Autonoma University of Madrid, Department of Agricultural Chemistry, Madrid (Spain)

    2008-01-15

    Isotope pattern deconvolution is a mathematical technique for isolating distinct isotope signatures from mixtures of natural abundance and enriched tracers. In iron metabolism studies measurement of all four isotopes of the element by high-resolution multicollector or collision cell ICP-MS allows the determination of the tracer/tracee ratio with simultaneous internal mass bias correction and lower uncertainties. This technique was applied here for the first time to study iron uptake by cucumber plants using {sup 57}Fe-enriched iron chelates of the o,o and o,p isomers of ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA) and ethylenediamine tetraacetic acid (EDTA). Samples of root, stem, leaves, and xylem sap, after exposure of the cucumber plants to the mentioned {sup 57}Fe chelates, were collected, dried, and digested using nitric acid. The isotopic composition of iron in the samples was measured by ICP-MS using a high-resolution multicollector instrument. Mass bias correction was computed using both a natural abundance iron standard and by internal correction using isotope pattern deconvolution. It was observed that, for plants with low {sup 57}Fe enrichment, isotope pattern deconvolution provided lower tracer/tracee ratio uncertainties than the traditional method applying external mass bias correction. The total amount of the element in the plants was determined by isotope dilution analysis, using a collision cell quadrupole ICP-MS instrument, after addition of {sup 57}Fe or natural abundance Fe in a known amount which depended on the isotopic composition of the sample. (orig.)

  16. Feasibility study of medical isotope production at Sandia National Laboratories

    International Nuclear Information System (INIS)

    Massey, C.D.; Miller, D.L.; Carson, S.D.

    1995-12-01

    In late 1994, Sandia National Laboratories in Albuquerque, New Mexico, (SNL/NM), was instructed by the Department of Energy (DOE) Isotope Production and Distribution Program (IPDP) to examine the feasibility of producing medically useful radioisotopes using the Annular Core Research Reactor (ACRR) and the Hot Cell Facility (HCF). Los Alamos National Laboratory (LANL) would be expected to supply the targets to be irradiated in the ACRR. The intent of DOE would be to provide a capability to satisfy the North American health care system demand for 99 Mo, the parent of 99m Tc, in the event of an interruption in the current Canadian supply. 99m Tc is used in 70 to 80% of all nuclear medicine procedures in the US. The goal of the SNL/NM study effort is to determine the physical plant capability, infrastructure, and staffing necessary to meet the North American need for 99 Mo and to identify and examine all issues with potential for environmental impact

  17. Isotope hydrology study of Kato Nevrokopi of Dramas

    International Nuclear Information System (INIS)

    Leontiadis, I.L.; Payne, B.R.; Letsios, A.; Papagianni, N.; Kakarelis, D.; Chadjiagorakis, D.

    1984-01-01

    The isotopic composition of the water was used in order to define the mechanism of recharge of the high plateau of Kato Nevrokopi of Dramas. The results of this study indicate that there are two main sources of recharge to groundwater. One is infiltration of water from the network of irrigation canals which carry water from the Vathitopos stream. The other source of recharge originates in the mountains to the east of the plain. Infiltration from the Nevrokopi stream does occur, but is believed to be minor in this part of the plain. Recharge by infiltration of local precipitation is considered to be minor in comparison with the two main sources of recharge. An underground barrier prevents draining of the groundwater through the sinkhole, resulting in a very big reservoir under the whole central and southern parts of the high plateau. The exploitation of the groundwater of this reservoir very probably offers a low-cost solution to satisfy all needs of the area for irrigation water. (author)

  18. Isotope hydrology study of Molai area in Laconia

    International Nuclear Information System (INIS)

    Leontiadis, J.L.

    1981-04-01

    The isotopic composition of the groundwater was used in order to investigate the mechanism of recharge of the Molai plain (Laconia) and of the coastal brackish springs of the area. The results of this study have shown that the Tripolitza carbonates, northeast of the plain, do not form a unique aquifer nor contribute to the recharge of the plain which is mainly fed by the local rainwater. The brackish springs at Glyfada are fed by the Tripolitza carbonates, northeast of the Mavrovouni-Koupia fault, through an isolated from the neogene aquifer of the plain conduit. The water content of the corresponding reservoir is estimated in the range of 2318 to 3091 hm 3 . The brackish springs at Plytra are fed by the marbles of Chavallas and Skardolakka mountains through the bedrock of Assopos river and the neogene aquifer of that part of the plain. The water content of the corresponding reservoir is estimated to be more than 284 hm 3 . The brackish coastal springs between Palea Monemvasia and Hierax are fed by the Tripolitza limestones southeast of the Mavrovouni-Koupia fault. (T.A.)

  19. Sr isotopic tracer study of the Samail ophiolite, Oman

    International Nuclear Information System (INIS)

    Lanphere, M.A.; Coleman, R.G.; Hopson, C.A.

    1981-01-01

    We have measured Rb and Sr concentrations and Sr isotopic compositions in 41 whole-rock samples and 12 mineral separates from units of the Samail ophiolite, including peridotite, gabbro, plagiogranite diabase dikes, and gabbro and websterite dikes within the metamorphic peridotite. Ten samples of cummulate gabbro from the Wadir Kadir section and nine samples from the Wadi Khafifah section have mean 87 Sr/ 86 Sr ratios and standard deviations of 0.70314 +- 0.00030 and 0.70306 +- 0.00034, respectively. The dispersion in Sr isotopic composition may reflect real heterogeneities in the magma source region. The average Sr isotopic composition of cumulate gabbro falls in the range of isotopic compositions of modern midocean ridge basalt. The 87 Sr/ 86 Sr ratios of noncumulate gabbro, plagiogranite, and diabase dikes range from 0.7034 to 0.7047, 0.7038 to 0.7046, and 0.7037 to 0.7061, respectively. These higher 87 Sr/ 86 Sr ratios are due to alteration of initial magmatic compositions by hydrothermal exchange with seawater. Mineral separates from dikes that cut harzburgite tectonite have Sr isotopic compositions which agree with that of cumulate gabbro. These data indicate that the cumulate gabbro and the different dikes were derived from partial melting of source regions that had similar long-term histories and chemical compositions

  20. Contribution of stable isotopes to the study of pharmacokinetics of magnesium salts; Apport des isotopes stables a l'etude de la pharmacocinetique de sels de magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Benech, H

    1999-05-28

    The use of stable isotopes as labels is becoming an attractive tool for the study of magnesium behavior in humans. It has been used two stable isotopes of magnesium, {sup 25}Mg and {sup 26}Mg, to measure the absolute bioavailability of a pharmaceutical form of magnesium. (N.C.)

  1. Contribution of stable isotopes to the study of pharmacokinetics of magnesium salts; Apport des isotopes stables a l'etude de la pharmacocinetique de sels de magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Benech, H

    1999-05-28

    The use of stable isotopes as labels is becoming an attractive tool for the study of magnesium behavior in humans. It has been used two stable isotopes of magnesium, {sup 25}Mg and {sup 26}Mg, to measure the absolute bioavailability of a pharmaceutical form of magnesium. (N.C.)

  2. Combining Solvent Isotope Effects with Substrate Isotope Effects in Mechanistic Studies of Alcohol and Amine Oxidation by Enzymes*

    Science.gov (United States)

    Fitzpatrick, Paul F.

    2014-01-01

    Oxidation of alcohols and amines is catalyzed by multiple families of flavin-and pyridine nucleotide-dependent enzymes. Measurement of solvent isotope effects provides a unique mechanistic probe of the timing of the cleavage of the OH and NH bonds, necessary information for a complete description of the catalytic mechanism. The inherent ambiguities in interpretation of solvent isotope effects can be significantly decreased if isotope effects arising from isotopically labeled substrates are measured in combination with solvent isotope effects. The application of combined solvent and substrate (mainly deuterium) isotope effects to multiple enzymes is described here to illustrate the range of mechanistic insights that such an approach can provide. PMID:25448013

  3. NMR studies of two spliced leader RNAs using isotope labeling

    Energy Technology Data Exchange (ETDEWEB)

    Lapham, J.; Crothers, D.M. [Yale Univ., New Haven, CT (United States)

    1994-12-01

    Spliced leader RNAs are a class of RNA molecules (<200 nts) involved in the trans splicing of messenger RNA found in trypanosomes, nematodes, and other lower eukaryotes. The spliced leader RNA from the trypanosome Leptomonas Collosoma exists in two alternate structural forms with similar thermal stabilities. The 54 nucleotides on the 5{prime} end of the SL molecule is structurally independent from the 3{prime} half of the RNA, and displays the two structural forms. Furthermore, the favored of the two structures was shown to contain anomalous nuclease sensitivity and thermal stability features, which suggests that there may be tertiary interactions between the splice site and other nucleotides in the 5{prime} end. Multidimensional NMR studies are underway to elucidate the structural elements present in the SL RNAs that give rise to their physical properties. Two spliced leader sequences have been studied. The first, the 54 nucleotides on the 5{prime} end of the L. Collosoma sequence, was selected because of earlier studies in our laboratory. The second sequence is the 5{prime} end of the trypanosome Crithidia Fasciculata, which was chosen because of its greater sequence homology to other SL sequences. Given the complexity of the NMR spectra for RNA molecules of this size, we have incorporated {sup 15}N/{sup 13}C-labeled nucleotides into the RNA. One of the techniques we have developed to simplify the spectra of these RNA molecules is isotope labeling of specific regions of the RNA. This has been especially helpful in assigning the secondary structure of molecules that may be able to adopt multiple conformations. Using this technique one can examine a part of the molecule without spectral interference from the unlabeled portion. We hope this approach will promote an avenue for studying the structure of larger RNAs in their native surroundings.

  4. Existence of halo-structure for the first excited levels of both the 13C-13N and the 17O-17F nuclei

    International Nuclear Information System (INIS)

    Gridnev, K.A.; Novatskij, B.G.

    2003-01-01

    From calculated the Coulomb shifts difference for the carbon and oxygen isotopes analog levels the valent nucleons the orbit radius values R C and the density parameter r 0 are presented. It is shown that the density parameter values are slightly varying for the all analog nuclear pairs. The exception constitutes the first excited states of the 13 C- 13 N and the 17 O- 17 F nuclei, whose valent nucleons populate the 2s-shell (L=0). These states one can to consider as structures with brightly distinguished of the ( 13 C * , 17 O * ) neutron halo and the( 13 N * , 17 F * ) proton halo

  5. Design study of fuel circulating system using Pd-alloy membrane isotope separation method

    International Nuclear Information System (INIS)

    Naito, T.; Yamada, T.; Yamanaka, T.; Aizawa, T.; Kasahara, T.; Nishikawa, M.; Asami, N.

    1980-01-01

    Design study on the fuel circulating system (FCS) for a tokamak experimental fusion reactor (JXFR) has been carried out to establish the system concept, to plan the development program, and to evaluate the feasibility of diffusion system. The FCS consists of main vacuum system, fuel gas refiners, isotope separators, fuel feeders, and auxiliary systems. In the system design, Pd-alloy membrane permeation method is adopted for fuel refining and isotope separating. All impurities are effectively removed and hydrogen isotopes are sufficiently separated by Pd-alloy membrane. The isotope separation system consists of 1st (47 separators) and 2nd (46 separators) cascades for removing protium and separating deuterium, respectively. In the FCS, while cryogenic distillation method appears to be practicable, Pd-alloy membrane diffusion method is attractive for isotope separation and refining of fuel gas. The choice will have to be based on reliability, economic, and safety analyses

  6. Lead isotopic studies of the Samail ophiolite, Oman

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.H.; Pallister, J.S.

    1981-04-10

    The isotopic composition of Pb and the concentrations of U, Th, and Pb have been determined for samples from various lithologic units and massive sulfides of the Samail ophiolite. The observed /sup 206/Pb//sup 204/Pb ratios range from 17.90 to 19.06, /sup 207/Pb//sup 204/Pb ratios from 15.43 to 15.63, and /sup 208/Pb//sup 204/Pb from 37.66 to 38.78. In Pb isotopic evolution diagrams, the initial Pb isotopic compositions of most of the samples from the Samail ophiolite plot within the field of oceanic basalt, clearly distinct from island arc data, and define some of the least radiogenic Pb observed from oceanic rocks. Lead data from the Samail are compatible with a model involving magma generation from an oceanic mantle source and formation of the ophiolite at an oceanic spreading center. U--Th--Pb isotopic systematics demonstrate that vertical heterogeneity in the oceanic crust can be created through differential concentration of U, Th, and Pb during crystal fractionation and alteration at, or near, the spreading ridge. Calcite form amygdules in the ophiolite basalt has similar Pb isotopic composition to the igneous rocks, suggesting precipitation of the calcite from seawater which contained Pb derived mostly from the oceanic crust. Lead isotopic data on Fe--Cu sulfides are also similar to the results from the igneous suite suggesting that the source of the sulfides is predominently from the oceanic crust. Lead data from serpentinized peridotite and a galena sample from below the ophiolite suggest that part of the serpentinization process and the formation of galena could involve addition of radiogenic Pb from either a continental source or from oceanic sediments.

  7. A theoretical study of cluster radioactivity in platinum isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Deepthy Maria; Ashok, Nithu; Joseph, Antony [University of Calicut, Department of Physics, Malappuram, Kerala (India)

    2018-01-15

    The probable cluster decay modes in platinum isotopes are predicted with the help of effective liquid drop model. The calculated half-lives are compared with those of universal decay law model and with the experimental data. The investigation affirms the decisive role of neutron magicity in the phenomenon of cluster radioactivity. It is found that the probability of cluster emission decreases with the increase in the neutron number of parent nucleus. Geiger-Nuttall plots of the probable decay modes show linear behaviour, which in turn leads to the equation for logarithmic half-life for the clusters emitted from Pt isotopes. (orig.)

  8. Inhibition of β-Secretase Activity by Monoterpenes, Sesquiterpenes, and C13 Norisoprenoids.

    Science.gov (United States)

    Marumoto, Shinsuke; Okuno, Yoshiharu; Miyazawa, Mitsuo

    2017-08-01

    Inhibition of β-secretase (BACE1) is currently regarded as the leading treatment strategy for Alzheimer's disease. In the present study, we aimed to screen the in vitro inhibitory activity of 80 types of aroma compounds (monoterpenes, sesquiterpenes, and C 13 norisoprenoids), including plant-based types, at a 200-μM concentration against a recombinant human BACE1. The results showed that the most potent inhibitor of BACE1 was geranyl acetone followed by (+)-camphor, (-)-fenchone, (+)-fenchone, and (-)-camphor with the half-maximal inhibitory concentration (IC 50 ) values of 51.9 ± 3.9, 95.9 ± 11.0, 106.3 ± 14.9, 117.0 ± 18.6, and 134.1 ± 16.4 μM, respectively. Furthermore, the mechanism of inhibition of BACE1 by geranyl acetone was analyzed using Dixon kinetics plus Cornish-Bowden plots, which revealed mixed-type mode. Therefore aroma compounds may be used as potential lead molecules for designing anti-BACE1 agents.

  9. Study of hyperfine anomaly in 9,11Be isotopes

    International Nuclear Information System (INIS)

    Parfenova, Y.; Leclercq-Willain

    2005-01-01

    The study of the hyperfine anomaly of neutron rich nuclei, in particular, neutron halo nuclei, can give a very specific and unique way to measure their neutron distribution and confirm a halo structure. The hyperfine structure anomaly in Be + ions is calculated with a realistic electronic wave function, obtained as a solution of the Dirac equation. In the calculations, the Coulomb potential modified by the charge distribution of the clustered nucleus and three electrons in the configuration 1s 2 2s is used. The nuclear wave function for the 11 Be nucleus is obtained in the core + nucleon model, and that for the 9 Be nucleus is calculated in the three-cluster (α+α + n) model. The aim of this study is to test whether the hyperfine structure anomaly reflects an extended spatial structure of '1 1 Be. The results of the calculations are listed. ε BW is the hyperfine anomaly in the Bohr-Weisskopf effect and δ is the charge structure correction, μ is the calculated magnetic moment, and μ exp is the experimental value of the magnetic moment, Q and Q exp are the calculated and measured values of the quadrupole moment. The results for 9 Be are obtained with two different three-body wave functions (WF1 and WF2) showing the sensitivity of the calculations to the input parameters. The value of ε BW is sensitive to the weights of the states in the nuclear ground state wave function. The total hyperfine anomaly value εε BW +δ in 11 Be differs from that in 9 Be by 25%. This gives a measure of the accuracy of the hyperfine anomaly measurements needed to study the neutron distribution in the Be isotopes. (authors)

  10. Stable-isotope studies. Progress report, March 1, 1980-August 25, 1982

    International Nuclear Information System (INIS)

    Ishida, T.

    1982-01-01

    Investigations during the past two-and-a half year priod have been directed toward the following three areas: (1) studies of vapor pressure isotope effects (fluoroform, methyl fluoride, methylene difluorides, ammonia); (2) studies on the fractionation of nitrogen isotope systems; and (3) theory of isotope effect. Studies on the fractionation of nitrogen isotope fractionaton systems involved two fronts. One is a study of 15 N-production by means of a countercurrent isotope exchange in a packed column between a gas phase, which is a mixture of various NO/sub x/, and a liquid phase, which is mainly N 2 O 3 and N 2 O 4 . The second deals with a concept of closed reflux cycle for the Nitrox and/or the NO/N 2 O 3 -process. In the theoretical field, studies of isotopic reduced partition function ratio has led to revelations of interesting correlations between molecular structures, molecular forces, and the isotope effects. The investigations for this period are summarized and a more thorough discussion is presented for each ongoing research

  11. C-13-carbohydrate breath tests : Impact of physical activity on the rate-limiting step in lactose utilization

    NARCIS (Netherlands)

    Stellaard, F; Koetse, HA; Elzinga, H; Boverhof, R; Tjoonk, R; Klimp, A; Vegter, D; Liesker, J; Vonk, RJ

    Background: (CO2)-C-13 breath tests can be used to monitor carbohydrate digestion in the small intestine. However, after ingestion of C-13-substrates, (CO2)-C-13 excretion in breath originates from two sources: a digestive/oxidative fraction, derived from the small intestine, and a fermentation

  12. Histidine side-chain dynamics and protonation monitored by C-13 CPMG NMR relaxation dispersion

    DEFF Research Database (Denmark)

    Hass, M. A. S.; Yilmaz, A.; Christensen, Hans Erik Mølager

    2009-01-01

    the chemical shift titration experiments, and the CPMG derived exchange rates agree with those obtained previously from N-15 backbone relaxation measurements. Compared to measurements of backbone nuclei, C-13(epsilon 1) dispersion provides a more direct method to monitor interchanging protonation states...... or other kinds of conformational changes of histidine side chains or their environment. Advantages and shortcomings of using the C-13(epsilon 1) dispersion experiments in combination with chemical shift titration experiments to obtain information on exchange dynamics of the histidine side chains...

  13. Isotope studies of UK tufa deposits and associated source waters

    International Nuclear Information System (INIS)

    Thorpe, P.M.

    1981-12-01

    Tufa is a secondary deposit of calcium carbonate precipitated from springs and streams. Previous attempts to date tufa deposits directly with 14 C have had limited success. The major problem is to quantify the amount of carbon incorporated in tufa, derived from the dissolution of carbonate bedrock, essentially free of 14 C. The isotopic composition of tufa-depositing streamwaters is similar to that of water recharging aquifers. The 14 C levels of recent tufa layers, at three sites, were similar to those of the source waters. 14 C dates from tufa at these sites suggested a Postglacial origin when corrected for bedrock carbon dilution of 16 to 24%. This dilution was overestimated by consideration of carbon mass balance using characteristic stable carbon isotope compositions (delta 13 C) for the biogenic and bedrock components. This method of correction is often applied to 14 C dates from groundwaters. The carbon isotope composition of spring waters supplying the tufa-depositing streams was realistically explained by a two stage process of carbonate dissolution under open and then closed conditions with respect to gaseous carbon dioxide. Seasonal variations in the 14 C and delta 13 C composition of stream and spring waters, downstream increases in 14 C and delta 13 C and seasonal variations in the oxygen and hydrogen isotopic composition of rainfall are explained. (author)

  14. Groundwater regimes and isotopic studies, Ranger mine area, Northern Territory

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M; Green, D C

    1986-12-01

    Three types of groundwater occur in the area of the Ranger mine. Type A groundwater occurs in the loose sands and gravels occupying the present day stream channels, Type B in the weathering profile and Type C occurs in relatively fresh fractured bedrock occupying open fractures and other cavities. The three types of groundwater can be distinguished both chemically and isotopically. Light stable isotope data suggest that most early rains are lost by evapotranspiration and have no imprint on the groundwater. Later in the wet season, the ground is saturated and groundwater recharge occurs on a regional scale. This younger groundwater sits on the older waters. Mixing is probably minimal as before any large scale mixing could occur, most younger waters are lost by evapotranspiration. Stable isotope data suggest that Type B groundwater in certain areas has some connection with evaporated surface water bodies. Stable isotope measurements for the pollution monitoring bores around the tailings dam do not indicate any connection with the polluted pond waters at the time of sample collection.

  15. Heating Isotopically Labeled Bernal Stacked Graphene: A Raman Spectroscopy Study

    Czech Academy of Sciences Publication Activity Database

    Ek Weis, Johan; da Costa, Sara; Frank, Otakar; Kalbáč, Martin

    2014-01-01

    Roč. 5, č. 3 (2014), s. 549-554 ISSN 1948-7185 R&D Projects: GA MŠk LL1301 Institutional support: RVO:61388955 Keywords : Bernal * graphene * isotopic labeling Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 7.458, year: 2014

  16. Hydrologic and isotopic study of the Quito aquifer

    International Nuclear Information System (INIS)

    Villalba, Fabio; Benalcazar, Julio; Garcia, Marco; Altamirano, Cesar; Altamirano, Homero; Sarasti, Santiago; Mancero, Maria; Leiva, Eduardo; Pino, Jose; Alulema, Rafael; Cedeno, Alberto; Burbano, Napoleon; Paquel, Efren; Becerra, Simon; Andrade, Graciela

    2000-10-01

    The dynamics of the Quito basin and surrounding area aquifers were determined through the use of stable and radioactive isotopes, and the monitoring of the freatic levels and of the bacteriological and physico-chemical quality of the water. A conceptual hydrodynamic model of the Quito aquifer was also proposed in order to establish in the future a sustainable management system

  17. Utility of stable isotope analysis in studying foraging ecology of herbivores: Examples from moose and caribou

    Science.gov (United States)

    Ben-David, Merav; Shochat, Einav; Adams, Layne G.

    2001-01-01

    Recently, researchers emphasized that patterns of stable isotope ratios observed at the individual level are a result of an interaction between ecological, physiological, and biochemical processes. Isotopic models for herbivores provide additional complications because those mammals consume foods that have high variability in nitrogen concentrations. In addition, distribution of amino acids in plants may differ greatly from that required by a herbivore. At northern latitudes, where the growing season of vegetation is short, isotope ratios in herbivore tissues are expected to differ between seasons. Summer ratios likely reflect diet composition, whereas winter ratios would reflect diet and nutrient recycling by the animals. We tested this hypothesis using data collected from blood samples of caribou (Rangifer tarandus) and moose (Alces alces) in Denali National Park and Preserve, Alaska, USA. Stable isotope ratios of moose and caribou were significantly different from each other in late summer-autumn and winter. Also, late summer-autumn and winter ratios differed significantly between seasons in both species. Nonetheless, we were unable to evaluate whether differences in seasonal isotopic ratios were a result of diet selection or a response to nutrient recycling. We believe that additional studies on plant isotopic ratios as related to ecological factors in conjunction with investigations of diet selection by the herbivores will enhance our understanding of those interactions. Also, controlled studies investigating the relation between diet and physiological responses in herbivores will increase the utility of isotopic analysis in studying foraging ecology of herbivores.

  18. International conference on isotopes in environmental studies - Aquatic Forum 2004. Book of extended synopses

    International Nuclear Information System (INIS)

    2004-01-01

    The International Conference on Isotopes in Environmental Studies: AQUATIC FORUM 2004, organized by the International Atomic Energy Agency (IAEA) was held in Monte-Carlo, Monaco, 25-29 October 2004. The principal objective of the Conference was to review recent achievements in the use of isotopic techniques to study marine and terrestrial environmental processes, transport of contaminants in the aquatic environment, climate change, computer modelling of environmental processes, present state of the art of isotopic techniques, data validation and syntheses, and the development of geographical information systems. This publication contains the extended synopses of presentations at the Conference

  19. International conference on isotopes in environmental studies - Aquatic Forum 2004. Book of extended synopses

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The International Conference on Isotopes in Environmental Studies: AQUATIC FORUM 2004, organized by the International Atomic Energy Agency (IAEA) was held in Monte-Carlo, Monaco, 25-29 October 2004. The principal objective of the Conference was to review recent achievements in the use of isotopic techniques to study marine and terrestrial environmental processes, transport of contaminants in the aquatic environment, climate change, computer modelling of environmental processes, present state of the art of isotopic techniques, data validation and syntheses, and the development of geographical information systems. This publication contains the extended synopses of presentations at the Conference.

  20. Study of the stability of the gallium isotopes beyond the N = 50 neutron shell closure

    CERN Multimedia

    We propose to study the stability of the nuclear structure beyond N = 50 and Z = 28 with beams of neutron-rich gallium isotopes at the CRIS experiment at ISOLDE. The study of their hyperne structure and isotope shift will provide spins, magnetic dipole moments, electric quadrupole moments and changes in the mean-square charge radii. The $\\beta$-decay of $^{80}$Ga will be unambiguously measured using the technique of Laser Assisted Nuclear Decay Spectroscopy (LANDS). The half-lives of the very neutron-rich isotopes with N > 54 will be measured for their impact on the astrophysical ${r}$-process.

  1. Environmental isotope study of a groundwater supply project in the Kalahari of Gordonia

    International Nuclear Information System (INIS)

    Verhagen, B.T.

    1984-01-01

    A feasibility study for a central fresh groundwater supply scheme in the Kalahari of the Gordonia district, South Africa, provided the opportunity to study fresh and saline water occurrences in detail with environmental isotopes. The isotopic and chemical signals show a clear contrast among groundwaters below a river bed, an extended fresh groundwater body and saline groundwaters in close proximity to the river. Carbon-14, tritium and stable-isotope data lead to a vertical rain recharge model rather than a regional flow mechanism for an understanding of the various water occurrences, their interrelationships and varied hydrochemistry. (author)

  2. High flux isotope reactor cold source preconceptual design study report

    International Nuclear Information System (INIS)

    Selby, D.L.; Bucholz, J.A.; Burnette, S.E.

    1995-12-01

    In February 1995, the deputy director of Oak Ridge National Laboratory (ORNL) formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced Neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. The anticipated cold source will consist of a cryogenic LH 2 moderator plug, a cryogenic pump system, a refrigerator that uses helium gas as a refrigerant, a heat exchanger to interface the refrigerant with the hydrogen loop, liquid hydrogen transfer lines, a gas handling system that includes vacuum lines, and an instrumentation and control system to provide constant system status monitoring and to maintain system stability. The scope of this project includes the development, design, safety analysis, procurement/fabrication, testing, and installation of all of the components necessary to produce a working cold source within an existing HFIR beam tube. This project will also include those activities necessary to transport the cold neutron beam to the front face of the present HFIR beam room. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and research and development (R and D), (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the preconceptual phase and establishes the concept feasibility. The information presented includes the project scope, the preliminary design requirements, the preliminary cost and schedule, the preliminary performance data, and an outline of the various plans for completing the project

  3. Critical overview on water - hydrogen isotopic exchange; a case study

    International Nuclear Information System (INIS)

    Peculea, Marius

    2002-01-01

    Water - hydrogen isotopic exchange process is attractive due to its high separation factor; it is neither corrosive or pollutant and, when used as a technological process of heavy water production, it requires water as raw material. Its efficiency depends strongly on the catalyst performance and geometry of the isotopic water - hydrogen exchange zone in which the isotopic transfer proceeds in two steps: liquid vapor distillation in the presence of an inert gas and a catalytic reaction in vapor - gas gaseous phase. An overview of the water hydrogen isotopic exchange is presented and technological details of the Trail - Canada facility as well as characteristics of the two pilots operated in Romania with Ni, Cr and hydrophobic catalysts are described. The mathematical approach of the successive water-water vapor-hydrogen isotopic exchange process given is based on a mathematical model worked out earlier by Palibroda. Discrepancies between computation and experimental results, lower than 11% for extreme cases and around 6% for the average range are explained as due to the ratio of the exchange potentials. Assumption is made in the theoretical approach that this ratio is positive and constant all long the column while the measurements showed that it varies within 0.7 and 1.1 at the upper end and within - 2.5 and - 4.4 at the lower end, what indicates a strong end effect. In conclusion it is stressed that a competing technological solution is emerging based on a monothermal electrolytic process or a bithermal - bibaric process both for heavy water and tritium separation process

  4. Adulteration of honey : relation between microscopic analysis and delta C-13 measurements

    NARCIS (Netherlands)

    Kerkvliet, JD; Meijer, HAJ

    2000-01-01

    Upon routine microscopic analysis of some honey samples, parenchyma cells, single rings of ring vessels and epidermal cells are found. These cells originate from the sugar cane stem. We investigated whether there was a relation between these plant fragments and the delta C-13 value of honey. 17

  5. Probing the possibility of a 12C13C abundance gradient from observations of interstellar CH+

    International Nuclear Information System (INIS)

    Hawkins, I.

    1987-01-01

    I have performed high signal-to-noise (SN /equals/ 300 to 500) observations of interstellar CH/sup /plus// at Lick Observatory and at CTIO of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a 12 C 13 C abundance gradient in our Galaxy

  6. OEDGE modeling of the DIII-D double null (CH4)-C-13 puffing experiment

    International Nuclear Information System (INIS)

    Elder, J.D.; Wampler, W.R.; McLean, A.G.; Stangeby, P.C.; Allen, S.L.; Bray, B.D.; Brooks, N.H.; Leonard, A.W.; Unterberg, Ezekial A.; Watkins, J.G.

    2011-01-01

    Unbalanced double null ELMy H-mode configurations in DIII-D are used to simulate the situation in ITER high triangularity, burning plasma magnetic equilibria, where the second X-point lies close to the top of the vacuum vessel, creating a secondary divertor region at the upper blanket modules. The measured plasma conditions in the outer secondary divertor closely duplicated those projected for ITER. (CH4)-C-13 was injected into the secondary outer divertor to simulate sputtering there. The majority of the C-13 found was in the secondary outer divertor. This material migration pattern is radically different than that observed for main wall (CH4)-C-13 injections into single null configurations where the deposition is primarily at the inner divertor. The implications for tritium codeposition resulting from sputtering at the secondary divertor in ITER are significant since release of tritium from Be co-deposits at the main wall bake temperature for ITER, 240 degrees C, is incomplete. The principal features of the measured C-13 deposition pattern have been replicated by the OEDGE interpretive code.

  7. IMPROVED LINE DATA FOR THE SWAN SYSTEM 12C13C ISOTOPOLOGUE

    International Nuclear Information System (INIS)

    Ram, Ram S.; Brooke, James S. A.; Bernath, Peter F.; Sneden, Christopher; Lucatello, Sara

    2014-01-01

    We present new, accurate predictions for rotational line positions, excitation energies, and transition probabilities of the 12 C 13 C isotopologue Swan d 3 Π-a 3 Π system 0-0, 0–1, 0–2, 1–0, 1–1, 1–2, 2–0, 2–1, and 2–2 vibrational bands. The line positions and energy levels were predicted through new analyses of published laboratory data for the 12 C 13 C lines. Transition probabilities were derived from recent computations of transition dipole moments and related quantities. The 12 C 13 C line data were combined with similar data for 12 C 2, reported in a companion paper, and applied to produce synthetic spectra of carbon-rich metal-poor stars that have strong C 2 Swan bands. The matches between synthesized and observed spectra were used to estimate band head positions for a few of the 12 C 13 C vibrational bands and to verify that the new computed line data match observed spectra. The much weaker C 2 lines of the bright red giant Arcturus were also synthesized in the band head regions

  8. Geological, Geochemical 1 and Rb-Sr isotopic studies on tungsten 2 ...

    Indian Academy of Sciences (India)

    37

    Geological, Geochemical and Rb-Sr isotopic studies on tungsten. 1 mineralised ..... From the field relations it is demonstrated that SG (biotite-bearing granitic gneiss) and. 120 ..... cases Ba) and vice-versa for the low concentration. 291.

  9. Parameter study on Japanese proposal of ITER hydrogen isotope separation system

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi; Enoeda, Mikio; Tanaka, Shigeru; Ohokawa, Yoshinao; Ohara, Atsushi; Nagakura, Masaaki; Naito, Taisei; Nagashima, Kazuhiro.

    1991-01-01

    As part of Japanese design contribution in the ITER activity, conceptual design of an entire ITER tritium system and their safety analysis have been carried out through the three-year period since 1988. The tritium system includes the following subsystems; - Fuelling (gas puffing and pellet injection) subsystem, - Torus vacuum pumping subsystem, - Plasma exhaust gas purification subsystem, - Hydrogen isotope separation subsystem, - NBI gas processing subsystem, - Blanket tritium recovery subsystem, - Tritiated water processing subsystem, - Tritium safety subsystem. Hydrogen isotope separation system is a key subsystem in the ITER tritium system because it is connected to all above subsystems. This report describes an analytical study on the Japanese concept of hydrogen isotope separation system. (author)

  10. Studies of isotopic effects in the excited electronic states of molecular systems

    International Nuclear Information System (INIS)

    1982-01-01

    Rare gas halogen (RGH) lasers serve as convenient tools for a range of photophysical processes which exhibit isotope effects. This document summarizes progress in the production of molecular systems in their electronic excited states with the aid of RGH lasers, and the various isotopic effects one can study under these conditions. We conclude that the basic physical mechanisms involved in the isotopically sensitive characteristics of excited molecular electronic states are sufficiently selective to be useful in both the detection and separation of many atomic materials

  11. Isotopic studies of rare gases in terrestrial samples and in natural nucleosynthesis

    International Nuclear Information System (INIS)

    Reynolds, J.H.

    1988-08-01

    This project is concerned with research in rare gas mass spectrometry. The broad objective is to read the natural record that isotopes of the rare gases comprise as trace constituents of natural gases, rocks, and meteorites. In past years, these interests have led to the study of such diverse problems as the dating of rocks, the early chronology and isotopic structure of the solar system as revealed by extinct radioactivities, and the elemental and isotopic composition of trapped primordial rare gases in meteorites. In recent years, the project has focused progressively more on terrestrial problems

  12. Isotopic studies of rare gases in terrestrial samples and in natural nucleosynthesis

    International Nuclear Information System (INIS)

    1987-07-01

    This project is concerned with research in rare gas mass spectrometry. The broad objective is to read the natural record that isotopes of the rare gases comprise as trace constituents of natural gases, rocks, and meteorites. In past years, these interests have led to the study of such diverse problems as the dating of rocks, the early chronology and isotopic structure of the solar system as revealed by extinct radioactivities, and the elemental and isotopic composition of trapped primordial rare gases in meteorites. In recent years, the project has focused progressively more on terrestrial problems

  13. Mechanistic studies on the bovine liver mitochondrial dihydroorotate dehydrogenase using kinetic deuterium isotope effects

    International Nuclear Information System (INIS)

    Hines, V.; Johnston, M.

    1989-01-01

    Dihydroorotates deuteriated at both C 5 and C 6 have been prepared and used to probe the mechanism of the bovine liver mitochondrial dihydroorotate dehydrogenase. Primary deuterium isotope effects on k cat are observed with both (6RS)-[5(S)- 2 H]- and (6RS)-[6- 2 H]dihydroorotates (3 and 6, respectively); these effects are maximal at low pH. At pH 6.6, D V = 3.4 for the C 5 -deuteriated dihydroorotate (3), and D V = 2.3 for the C 6 -deuteriated compound (6). The isotope effects approach unity at pH 8.8. Analysis of the pH dependence of the isotope effects on k cat reveals a shift in the rate-determining step of the enzyme mechanism as a function of pH. Dihydroorotate oxidation appears to require general base catalysis; this step is completely rate-determining at low pH and isotopically sensitive. Reduction of the cosubstrate, coenzyme Q 6 , is rate-limiting at high pH and is isotopically insensitive; this step appears to require general acid catalysis. The results of double isotope substitution studies and analysis for substrate isotope exchange with solvent point toward a concerted mechanism for oxidation of dihydroorotate. This finding serves to distinguish further the mammalian dehydrogenase from its parasitic cognate, which catalyzes a stepwise oxidation reaction

  14. Stable isotope variations in benthic primary producers along the Bosphorus (Turkey): A preliminary study

    International Nuclear Information System (INIS)

    Calizza, Edoardo; Aktan, Yelda; Costantini, Maria Letizia; Rossi, Loreto

    2015-01-01

    Highlights: • Nitrogen pollution along the Bosphorus Strait was investigated. • C and N isotopic and elemental analyses on benthic primary producers were performed. • δ 15 N decreased, while δ 13 C and N% increased from north to south along the Strait. • Ulva lactuca was more useful than epiphytes as indicator of nitrogen pollution. • Preliminary isotopic analyses on resident organisms are useful monitoring tools. - Abstract: The Bosphorus Strait is a dynamic and complex system. Recent evidences showed nitrogen and heavy metal concentrations to follow opposite patterns across the Strait, suggesting a complex spatial organisation of the anthropogenic disturbance in this system. Here, we provide isotopic information on the origin and transportation of dissolved nitrogen along the Bosphorus. C and N isotopic and elemental analyses were performed on specimens of Ulva lactuca and associated epiphytes sampled in five locations across the Strait. Variations in C and N isotopic signatures were observed in U. lactuca, pointing to a decrease in the availability of anthropogenic organic dissolved nitrogen along a north-south direction. Conversely, epiphytes did not show isotopic or elemental patterns across the Strait. These results suggest that preliminary stable isotope surveys in extended costal systems basing on U. lactuca can represent a valuable tool to focus meaningful targets and hypotheses for pollution studies in the Mediterranean region

  15. Contribution to optimisation of Environmental Isotopes tracing in Hydrogeology. Case study of Madagascar

    International Nuclear Information System (INIS)

    RAJAOBELISON, J.

    2003-01-01

    The aim of this work is to suggest some improvements on the theory of interpretation and on the methodological approach for the optimum use of environmental isotopes tracing applied to hydrogeological investigation. A review of the theory of environmental isotopes used in hydrogeology has been made. The main constraints have been highlighted and led to some comments and proposals of improvement, in particular with regard to the continental effect on stable isotopes, to the seasonal variation of groundwater 1 4C content, and to the appropriate model for fractured crystalline aquifers. A literature survey on ten specific scientific papers, dealing with isotopic hydrology in miscellaneous types of aquifers and catchments, allowed to draw a synthesis of the hydrogeological, geochemical and isotopic constraints. A proposal of optimum methodological approach, taking into account the above mentioned constraints, have been inferred. The results of an on-going hydrogeological investigation carried out in the Southern crystalline basement and coastal sedimentary aquifers of Madagascar highlights an unusual methodological approach based on the lack of initial basic hydrogeological data. Besides, it shows to what extent the experience of the above mentioned research works can apply in the specific case of the complex aquifers of Madagascar. The lessons gained from this study contribute to enrich the synthesis of environmental isotopes constraints in hydrogeology and lead to a more realistic methodological approach proposal wich is likely to better make profitable the isotope hydrology technology

  16. Lead isotope ratios as a tracer for lead contamination sources: A lake Andong case study

    Directory of Open Access Journals (Sweden)

    Kim Y. H

    2013-04-01

    Full Text Available The objective of this study was to evaluate stable Pb isotope signatures as a tracer for Pb contamination in Lake Andong. For Pb isotope analysis, we collected water and sediment from Lake Andong, particles in the air, soils, and stream water, mine tailings, sludge and wastewater from zinc smelting around lake Andong watershed. The results showed that Pb isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb for zinc concentrate were 18.809 ± 0.322, 15.650 ± 0.062, and 38.728 ± 0.421, respectively. In wastewater, isotopic ratio values (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb were 17.363 ± 0.133, 15.550 ± 0.025, and 37.217 ± 0.092, respectively. Additionally, isotopic ratio values (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb for sludge were 17.515 ± 0.155, 15.537 ± 0.018, and 37.357 ± 0.173, respectively. These values were similar to those in zinc and lead concentrate originated from Canada and South America. In contrast, Pb isotope ratios of soil, tailings and sediment from Lake Andong were similar to those of Korean ore. Atmospheric particles showed different patterns of Pb isotope ratios from sediments, soils, and zinc smelting and this needs further investigation in order to identify atmospheric Pb sources.

  17. Neutron-rich polonium isotopes studied with in-source laser spectroscopy

    CERN Document Server

    Dexters, Wim; Cocolios, T E

    This work studies the unknown region of neutron rich polonium isotopes. The polonium isotopes, with Z=84, lie above the magic lead nuclei (Z=82). The motivation for this research can mainly be found in these lead nuclei. When looking at the changes in the mean square charge radii beyond the N=126 shell gap, a kink is observed. This kink is also found in the radon (Z=86) and radium (Z=88) isotopes. The observed effect cannot be reproduced with our current models. The polonium isotopes yield more information on the kink and they are also able to link the known charge radii in lead isotopes to those in radon and radium. Additionally, the nuclear moments of the odd-neutron isotope $^{211}$Po are investigated. This nucleus has two protons and one neutron more than the doubly magic nucleus $^{208}$Pb. Nuclear moments of isotopes close to this doubly magic nucleus are good tests for the theoretic models. Besides pushing the models to their limits, the nuclear moments of $^{211}$Po also yield new information on the f...

  18. Study of polonium isotopes ground state properties by simultaneous atomic- and nuclear-spectroscopy

    CERN Multimedia

    Koester, U H; Kalaninova, Z; Imai, N

    2007-01-01

    We propose to systematically study the ground state properties of neutron deficient $^{192-200}$Po isotopes by means of in-source laser spectroscopy using the ISOLDE laser ion source coupled with nuclear spectroscopy at the detection setup as successfully done before by this collaboration with neutron deficient lead isotopes. The study of the change in mean square charge radii along the polonium isotope chain will give an insight into shape coexistence above the mid-shell N = 104 and above the closed shell Z = 82. The hyperfine structure of the odd isotopes will also allow determination of the nuclear spin and the magnetic moment of the ground state and of any identifiable isomer state. For this study, a standard UC$_{x}$ target with the ISOLDE RILIS is required for 38 shifts.

  19. Isotope labeling strategies for NMR studies of RNA

    International Nuclear Information System (INIS)

    Lu, Kun; Miyazaki, Yasuyuki; Summers, Michael F.

    2010-01-01

    The known biological functions of RNA have expanded in recent years and now include gene regulation, maintenance of sub-cellular structure, and catalysis, in addition to propagation of genetic information. As for proteins, RNA function is tightly correlated with structure. Unlike proteins, structural information for larger, biologically functional RNAs is relatively limited. NMR signal degeneracy, relaxation problems, and a paucity of long-range 1 H- 1 H dipolar contacts have limited the utility of traditional NMR approaches. Selective isotope labeling, including nucleotide-specific and segmental labeling strategies, may provide the best opportunities for obtaining structural information by NMR. Here we review methods that have been developed for preparing and purifying isotopically labeled RNAs, as well as NMR strategies that have been employed for signal assignment and structure determination.

  20. Studies of neutron-deficient mendelevium isotopes at SHIP

    Energy Technology Data Exchange (ETDEWEB)

    Antalic, S.; Saro, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Hessberger, F.P.; Ackermann, D.; Heinz, S.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Goethe-Universitaet, Institut fuer Kernphysik, Frankfurt am Main (Germany); Kuusiniemi, P. [University of Oulu, Centre for Underground Physics in Pyhaesalmi (CUPP), Oulu (Finland); Leino, M. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)

    2010-01-15

    The radioactive decay of the isotopes {sup 247}Md, {sup 246}Md and their daughter products was investigated by means of {alpha}-{alpha} and {alpha}-{gamma} coincidence spectroscopy. The isotopes were produced using the fusion reaction {sup 40}Ar + {sup 209}Bi. Decay schemes are suggested for {sup 247}Md and {sup 243}Es. A new isomeric state in {sup 246}Md with a half-life of (4.4{+-}0.8) s was observed. Previous data of electron-capture delayed fission of {sup 246}Md and {sup 242}Es were confirmed. The probability for this decay branch in {sup 246}Md was measured to be P{sub ECDF}>0.10. The probability for electron-capture delayed fission in the case of {sup 242}Es was determined to be P{sub ECDF}=0.013{sup +0.012} {sub -0.007}. (orig.)

  1. Measurement of boron isotope ratios in groundwater studies

    International Nuclear Information System (INIS)

    Porteous, N.C.; Walsh, J.N.; Jarvis, K.E.

    1995-01-01

    Boron is present at low levels in groundwater and rainfall in the UK, ranging between 2 and 200 ng ml -1 . A sensitive technique has been developed using inductively coupled plasma mass spectrometry (ICP-MS) to measure boron isotope ratios at low concentrations with a precision (s r ) of between 0.1 and 0.2%. Samples were evaporated to increase elemental boron concentrations to 200 ng ml -1 and interfering matrix elements were removed by an adapted cation-exchange separation procedure. The validity of measuring boron isotopic ratios by ICP-MS at this concentration level is discussed in relation to the theoretical instrument precision attainable based on counting statistics. (author)

  2. Determinations of the 12C/13C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi

    Science.gov (United States)

    Harrison, Thomas E.; Marra, Rachel E.

    2017-07-01

    We present new moderate-resolution near-infrared spectroscopy of three CVs obtained using GNIRS on Gemini-North. These spectra covered three 13CO bandheads found in the K-band, allowing us to derive the isotopic abundance ratios for carbon. We find small 12C/13C ratios for all three donor stars. In addition, these three objects show carbon deficits, with AE Aqr being the most extreme ([C/Fe] = -1.4). This result confirms the conjecture that the donor stars in some long-period CVs have undergone considerable nuclear evolution prior to becoming semi-contact binaries. In addition to the results for carbon, we find that the abundance of sodium is enhanced in these three objects, and the secondary stars in both RU Peg and SS Cyg suffer magnesium deficits. Explaining such anomalies appears to require higher mass progenitors than commonly assumed for the donor stars of CVs. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil).

  3. The use of stable isotopes for studies on the physiology of plants

    International Nuclear Information System (INIS)

    Moyse, Alexis.

    1982-01-01

    The use of the stable isotopes 15 N, 18 O, 13 C for studies on the physiology of plants especially of plants grown under natural environment conditions is reviewed. Analysis of isotopic discrimination give estimates of the various patterns of carbon and nitrogen nutrition and of the rate of water circulation. The method can also be used for paleoclimatology and for the detection of frauds in food products [fr

  4. Studies of geothermal background and isotopic geochemistry of thermal waters in Jiangxi Province

    International Nuclear Information System (INIS)

    Zhou Wenbin; Sun Zhanxue; Li Xueli; Shi Weijun

    1996-10-01

    The terrestrial heat flow measurement, isotope and geochemical techniques have been systematically applied to the geothermal systems in Jiangxi Province. Results show that the thermal waters in the study area all belong to the low-medium temperature convective geothermal system, which essentially differs from high temperature geothermal systems with deep magmatic heat sources. It has been proven that the isotope and geochemical techniques are very useful and effective in geothermal exploration. (13 refs., 14 tabs., 8 figs.)

  5. ICP-MS as the method of the determination of gallium, indium and thallium isotope ratios in the studies of isotope effects in the chromatography systems

    International Nuclear Information System (INIS)

    Herdzik, I.

    2006-01-01

    The procedure of the determination of gallium, indium and thallium isotope ratios and its application to the studies of the isotope effects in chromatography systems by the ICP-MS method (inductively coupled plasma-mass spectrometry) are presented. It was shown that it is possible to determine the isotope ratios of gallium ( 69/71 Ga), indium ( 113/115 In) and thallium ( 203/205 Tl) with the relative standard deviation 0.03-0.07%. Such precision appeared to be sufficient to calculate the unit separation factors in the column chromatographic processes. (author) [pl

  6. Molecular modeling study of lithium isotopic separation by crown-ethers in ethanol

    International Nuclear Information System (INIS)

    Dehez, F.

    2002-01-01

    The isotopic separation of lithium ion isotopes is studied at the CEA in Pierrelatte using a liquid chromatography technique. Exchange systems are composed by crown-ethers grafted on silica (12C4, 15C5, B15C5, DB15C5, 18C6, B18C6). Lithium is introduced as a salt melted in ethanol. This work concerns the theoretical study of lithium isotopic exchange reactions with those systems. After a brief presentation of isotope separation techniques and isotopic effects (Chap.I), we describe the methods of theoretical chemistry used in this work (Chap. II). In chapter III, we test AM1 and PM3 semi-empirical methods for the treatment of Li + /crown-ether species. Then, we calculate isotopic separation factors via ab initio and semi-empirical calculations for the exchange reactions in vacuum. The different crown-ethers are considered with and without graftings arms. Studies of exchange reactions in ethanol are presented in chapter IV. First, each species of the reaction are solvated by a few ethanol molecules. Isotopic separation factors calculated show a large effect of the solvent on the exchange reaction. The effect of the grafting arm has been investigated using hybrid quantum mechanics/molecular mechanics (QM/MM) molecular dynamics for species with the 12C4. Trajectories have been generated successively with 7 Li and 6 Li. Atomic velocity autocorrelation functions have allowed the access to vibrational frequencies necessary to calculate isotopic separation factors. The last chapter is devoted to methodological developments made during this Ph.D. We propose an approach to treat long range electrostatic interactions in hybrid QM/MM method, relying on a lattice summation technique. (author) [fr

  7. Study of reactions of isotopic exchange of trans-zeatin with tritium

    International Nuclear Information System (INIS)

    Sidorov, G.V.; Myasoedov, N.F.

    2006-01-01

    Reactions of isotopic exchange of trans-zeatin with high-radioactive tritium water, with gaseous tritium in solution and solid-phase catalytic hydrogenation are studied to prepare trans-zeatin and dihydrozeatin labelled with tritium. It is shown that reaction of isotopic exchange of trans-zeatin with gaseous tritium both in solutions and without solvents at 160 Deg C and above leads to practically total hydrogenation of initial compound with formation of dihydrozeatin labelled with tritium. Isotopic exchange with tritium water permits to prepare zeatin labelled with tritium with 67 % yield and specific radioactivity 0.68 PBq/mol. It is determined that in the case of solid-phase isotopic exchange within 150-155 Deg C temperature interval both dihydrozeatin and trans-zeatin labelled with tritium are formed [ru

  8. Study of yrast bands and electromagnetic properties in neutron-rich 114-128Cd isotopes

    Science.gov (United States)

    Chaudhary, Ritu; Pandit, Rakesh K.; Devi, Rani; Khosa, S. K.

    2018-02-01

    The projected shell model framework has been employed to carry out a systematic study on the deformation systematics of E (21+) and E (41+) / E (21+) values, BCS subshell occupation numbers, yrast spectra, backbending phenomena and electromagnetic quantities in 114-128Cd isotopes. Present calculations reproduce the observed systematics of the E (21+), R42 and B (E 2 ;2+ →0+) values for 114-128Cd isotopic mass chain and give the evidence that deformation increases as one moves from 114Cd to 118Cd, thereafter it decreases up to 126Cd. This in turn confirms 118Cd to be the most deformed nucleus in this set of isotopic mass chain. The emergence of backbending, decrease in B (E 2) values and change in g-factors in all these isotopes are intimately related to the crossing of g-band by 2-qp bands.

  9. Chemical and environmental isotopes study of precipitation in Syria

    International Nuclear Information System (INIS)

    Al-Charideh, A.; Abou Zakhem, B.

    2009-02-01

    Chemical and isotopic compositions of monthly precipitation were monitored at 12 stations distributed over the entire region in Syria for a period of 4 years from December 1999 to April 2003. Amount of precipitation and mean air temperature of rain monthly were also recorded. The conductivity of rain waters varies between 35 μ/cm in the mountainous stations and 336 μ/cm at Deir Az-Zor station. Excepted Tartous station, the mean value of Cl in the rainfall in all station is 3.8 mg/l. The seasonal variations in δ 18 O are smaller at west stations than to the east stations due to low seasonal temperature variations. All stations are characterized by water lines with slopes significantly lower than GMWL, except Bloudan, suggesting the influence of local factors on the isotopic composition of the precipitation. d-excess values decrease from 19% in the western part to 13% in the eastern part of Syria, indicating the influence of the precipitation generated by the air masses coming from the Mediterranean Sea over Syria. A reliable altitude effect represent by depletion of heavy stable isotopes of about -0.21, and -1.47, per 100 m elevation of 18 O and δ 2 H, respectively. Monthly tritium activity and seasonal variations pattern are low in the west stations than at the east stations. The weighted mean tritium values are between 3 to 9 TU during 2000-2003, and it is increasing with distance from the Syrian coast by 1 TU /100 Km. (author)

  10. Zinc absorption study using an enriched stable isotope (70Zn)

    International Nuclear Information System (INIS)

    Li Gongpan.

    1990-04-01

    A weaning food from fermented soybean was prepared for increasing the bioavailability of zinc. The zinc absorption was compared with that of a weaning food from non-fermented soybean and normal staple food. A stable isotope tracer technique ( 70 Zn) and neutron activation were used for determining the absorption of zinc. Nine children aged 7 to 18 months were tested. Zinc bioavailability of weaning food from fermented soybean is higher than that of normal weaning food. The weight increment and zinc nutrition of children having weaning food from fermented soybean are improved by this diet. 5 tabs

  11. Isotopic studies on oxidative methane coupling over samarium oxide

    International Nuclear Information System (INIS)

    Otsuka, Kiyoshi; Inaida, Masakatsu; Wada, Yuji; Komatsu, Takayuki; Morikawa, Akira

    1989-01-01

    The evident kinetic isotope effect was observed for the formations of ethylene and ethane through the oxidative coupling of methane on Sm 2 O 3 , when CH 4 and CD 4 were used as the reactants. Ethanes formed in the reaction of a mixture of CH 4 , CD 4 , and O 2 were C 2 H 6 , C 2 H 3 D 3 , and C 2 D 6 as major products. These results indicate that the rate-determining step of the reaction is abstraction of hydrogen from methane and that ethane is formed through the coupling of methyl intermediate. (author)

  12. Isotope studies on the comparative efficiency of nitrogenous sources

    Energy Technology Data Exchange (ETDEWEB)

    Dev, G; Rennie, D A [Saskatchewan Univ., Saskatoon (Canada). Dept. of Soil Science

    1979-03-01

    In a growth chamber experiment with /sup 15/N-labelled potassium nitrate, ammonium sulphate and urea at 75 and 150kg nitrogen/ha and ammonium nitrate at 150kg nitrogen/ha, nitrogen application produced significant responses of dry matter yield and total nitrogen uptake by shoot and root of barley in chernozemic dark brown Elstow silt loam and deep black Hoey clay soil. Total nitrogen removal per pot and isotope-derived criteria, viz. percentage nitrogen derived from fertilizer, 'A' value and percentage fertilizer nitrogen utilization, indicated that potassium nitrate was the most efficient and urea the least.

  13. Preliminary isotopic study of Lake Asal system (Republic of Djibouti)

    International Nuclear Information System (INIS)

    Fontes, J.C.; Zuppi, G.M.; Florkowski, T.; Pouchan, P.

    1979-01-01

    The saline Lake Asal at 155 m below sea level in the Afar Rift (Republic of Djibouti) is fed mainly by sea water. In spite of the intense evaporation (about 3 m annually), the 18 O and deuterium enrichments of the lake water are relatively low, because of the reduced activity of water as a consequence of the high salt content. Isotopic balance of the lake, as well as lithium and sulphate balances, support the hypothesis of leakages from the lake of about 15 to 20% of the inflow. (author)

  14. Application of Stable Isotope-Assisted Metabolomics for Cell Metabolism Studies

    Science.gov (United States)

    You, Le; Zhang, Baichen; Tang, Yinjie J.

    2014-01-01

    The applications of stable isotopes in metabolomics have facilitated the study of cell metabolisms. Stable isotope-assisted metabolomics requires: (1) properly designed tracer experiments; (2) stringent sampling and quenching protocols to minimize isotopic alternations; (3) efficient metabolite separations; (4) high resolution mass spectrometry to resolve overlapping peaks and background noises; and (5) data analysis methods and databases to decipher isotopic clusters over a broad m/z range (mass-to-charge ratio). This paper overviews mass spectrometry based techniques for precise determination of metabolites and their isotopologues. It also discusses applications of isotopic approaches to track substrate utilization, identify unknown metabolites and their chemical formulas, measure metabolite concentrations, determine putative metabolic pathways, and investigate microbial community populations and their carbon assimilation patterns. In addition, 13C-metabolite fingerprinting and metabolic models can be integrated to quantify carbon fluxes (enzyme reaction rates). The fluxome, in combination with other “omics” analyses, may give systems-level insights into regulatory mechanisms underlying gene functions. More importantly, 13C-tracer experiments significantly improve the potential of low-resolution gas chromatography-mass spectrometry (GC-MS) for broad-scope metabolism studies. We foresee the isotope-assisted metabolomics to be an indispensable tool in industrial biotechnology, environmental microbiology, and medical research. PMID:24957020

  15. A multielement isotopic study of refractory FUN and F CAIs: Mass-dependent and mass-independent isotope effects

    Science.gov (United States)

    Kööp, Levke; Nakashima, Daisuke; Heck, Philipp R.; Kita, Noriko T.; Tenner, Travis J.; Krot, Alexander N.; Nagashima, Kazuhide; Park, Changkun; Davis, Andrew M.

    2018-01-01

    Calcium-aluminum-rich inclusions (CAIs) are the oldest dated objects that formed inside the Solar System. Among these are rare, enigmatic objects with large mass-dependent fractionation effects (F CAIs), which sometimes also have large nucleosynthetic anomalies and a low initial abundance of the short-lived radionuclide 26Al (FUN CAIs). We have studied seven refractory hibonite-rich CAIs and one grossite-rich CAI from the Murchison (CM2) meteorite for their oxygen, calcium, and titanium isotopic compositions. The 26Al-26Mg system was also studied in seven of these CAIs. We found mass-dependent heavy isotope enrichment in all measured elements, but never simultaneously in the same CAI. The data are hard to reconcile with a single-stage melt evaporation origin and may require reintroduction or reequilibration for magnesium, oxygen and titanium after evaporation for some of the studied CAIs. The initial 26Al/27Al ratios inferred from model isochrons span a range from <1 × 10-6 to canonical (∼5 × 10-5). The CAIs show a mutual exclusivity relationship between inferred incorporation of live 26Al and the presence of resolvable anomalies in 48Ca and 50Ti. Furthermore, a relationship exists between 26Al incorporation and Δ17O in the hibonite-rich CAIs (i.e., 26Al-free CAIs have resolved variations in Δ17O, while CAIs with resolved 26Mg excesses have Δ17O values close to -23‰). Only the grossite-rich CAI has a relatively enhanced Δ17O value (∼-17‰) in spite of a near-canonical 26Al/27Al. We interpret these data as indicating that fractionated hibonite-rich CAIs formed over an extended time period and sampled multiple stages in the isotopic evolution of the solar nebula, including: (1) an 26Al-poor nebula with large positive and negative anomalies in 48Ca and 50Ti and variable Δ17O; (2) a stage of 26Al-admixture, during which anomalies in 48Ca and 50Ti had been largely diluted and a Δ17O value of ∼-23‰ had been achieved in the CAI formation region; and (3

  16. Studying of isotope structure of uranium by alpha-spectrometric method

    International Nuclear Information System (INIS)

    Sattarov, G.S.; Muzafarov, A.M.; Petukhov, O.F.; Petrenko, V.Z.

    2004-01-01

    Full text: The knowledge of isotope structure of uranium in waters, in minerals and in finished goods gives the helpful information on the radiation and nuclear-physical processes occurring in natural environments. Besides, customers put a question before uranium producing enterprises on the control of limiting concentration of an isotope 234 U in finished goods (uranium protoxide-oxide). For these reasons studying and development of techniques of definition of isotope structure of uranium is an actual task. In this connection for researches alpha - spectrometers 'PROGRESS-ALPHA' produced by R and D 'DOZE' Russia and firms 'Canberra' the USA were used. The isotope structure of uranium ( 234 U, 235 U, 238 U) was determined on a known ratio 234 U/ 238 U, which is equal to 53,41micrograms/gram. Identification of isotopes carried out by 4198 keV ( 235 U), 4395 keV ( 234 U) and 4773 keV ( 238 U). The technique of radiochemical preparation of samples to the analysis included: clearing of organic chemistry and preventing natural isotopes; drawing by a method electrolytic sedimentation on a metal substrate (d=24mm) an active stain, the area 4,5 cm 2 , with isotropy distribution of ions 234 U, 235 U, 238 U. As standards, the international and All-Russian standards with known contents 234 U were used. The isotope structure of uranium in uranium protoxide-oxide, chemical concentrates, technological solutions is determined. Infringements of isotope balance 234 U/ 238 U on separate sites of fulfilled uranium deposits and in technological products are found out

  17. Chemical and environmental isotope study of precipitation in Syria

    International Nuclear Information System (INIS)

    Kattan, Z.

    1999-01-01

    Waters from a network of rainfall collection covering mine meteorological stations distributed mainly in the western part of Syria have been assayed using chemical and environmental isotope techniques for a period of 5 months from Dec. 1989 to Apr. 1990. The chemistry of rain waters falling over the mountainous stations shows a low solute concentration (20-105 mg 1 -1 ) compared with those falling over the coastal and anterior stations (50-210 mg 1 -1 ). The rain waters was generally characterized by a high deuterium excess (d=19%) compared with that of typical global meteoric waters (d=10%). The estimated deuterium excess is lower than that for the eastern Mediterranean meteoric waters (d=22%). The altitude effect is shown up by a depletion of heavy stable isotopes of about - 0.23% and -1.65% per 100 m elevation of δ 1 8 O and δD, respectively. The spatial distribution pattern of tritium contents shows a gradual build up with increasing distance from the Syrian coast. The weighted mean tritium content in rain waters falling over the country is estimated to amount to 9.5 tritium units (TU) during the period of observation. (author)

  18. Calculation of turnover rates in stable-isotope studies

    International Nuclear Information System (INIS)

    Wootton, R.; Ford, G.C.; Cheng, K.N.; Halliday, D.

    1985-01-01

    In a comparison of glucose turnover measured with 2 H-glucose and with 13 C-glucose Tserng and Kalhan used five apparently different equations and obtained conflicting answers. There is, however, no difference in principle between the use of a stable isotope as a tracer and the use of a radioactive isotope, and the rate of appearance of tracee in a steady-state system (the turnover) can therefore be shown to be proportional to the equilibrium dilution of the infused tracer. Because the sensitivity of measurement of this dilution made using a gas chromatograph-mass spectrometer is lower than that made by radioactivity measurement, the contribution to the measured turnover rate due to the infusate cannot be neglected, as it usually is in radioisotope work. A convenient calibration curve to establish this dilution is the mole ratio of the pure infusate against the area ratio for the relevant ions. Tserng and Kalhan's apparently conflicting results for glucose-turnover using 13 C-glucose as the tracer can all be shown to amount to approximately 11.6 μmol min -1 kg -1 . This value is only slightly lower (0.05 2 H-glucose as the tracer and supports the use of 13 C-glucose as an alternative. (author)

  19. Positional isotope exchange studies on enzyme using NMR spectroscopy

    International Nuclear Information System (INIS)

    Matsunaga, T.O.

    1987-01-01

    The isotopically enriched compounds, 18 O-β,γ-ATP and 18 O bridge-labeled pyrophosphate, synthesized previously in this laboratory, were used to investigate and measure the exchange vs. turnover of substrates and products from their central complexes in four selected enzyme systems. Using hi-field 31 P NMR, we were able to differentiate between 18 O labeled in the bridge vs. the non-bridge positions by virtue of the isotope shift upon the phosphorus nuclei. The bridge to non-bridge scrambling of the label was quantitated and the exchange vs. turnover ratios under a variety of conditions was determined. Using the substrate inhibitor carboxycreatinine, PIX experiments with 18 O-β,γ-ATP and creatine kinase were conducted. It was shown that carboxycreatinine and creatine kinase promoted exchange of the 18 O label as determined by NMR. We have concluded that carboxycreatinine is either a substrate that catalyzes very slow turnover or it catalyzes exchange by a dissociative (SN 1 /sub P/) type of mechanism

  20. Biogeochemical studies of lead isotopes near a smelter

    International Nuclear Information System (INIS)

    Landrigan, P.J.; Baker, E.L. Jr.; Earl, J.L.; Chow, T.J.

    1975-01-01

    Ninety-nine percent of 1 to 9 year-old children living within 1 mile of a primary lead smelter in Idaho were found to have whole blood lead levels equal to or greater than 40μg/100 ml, a level indicative of excess lead absorption. To define the sources of this lead, isotope ratios were determined in lead from human and environmental samples obtained near the smelter; determinations were performed using a 30-cm radius, solid-source mass spectrometer with an electron multiplier. The Idaho ore is a pre-Cambrian lead deposit with 206 Pb/ 204 Pb = 16.43, 206 Pb = 1.0543 and 206 Pb/ 208 Pb = 0.4518. An ingot smelted in 1974 showed isotope ratios of 206 Pb/ 204 Pb = 17.66, 206 Pb/ 207 Pb = 1.1312 and 206 Pb/ 208 Pb = 0.4694, indicating a mixture of ore sources. Three surface soil samples from within 2 miles of the smelter had lead ratios similar to those in the ingot. A fourth soil sample from beside an interstate highway 32 miles east of the smelter showed different ratios: 206 Pb/ 204 Pb = 18.47, 206 Pb/ 207 Pb = 1.1826 and 206 Pb/ 208 Pb = 0.4823. Aerosol samples collected from October 4, 1974, to February 1, 1975, near the smelter showed considerable variation in ratios; these variations resulted from smelting of ores from differing sources

  1. Studies of isotopic hydrology in Latin America 2006

    International Nuclear Information System (INIS)

    2009-04-01

    Policies for the exploitation of groundwater as a complement to surface water resources are frequently based on short term planning and may not be sustainable over time. The objective of sustainable groundwater management is to use groundwater in conjunction with surface waters in such a way that a state of equilibrium is reached in terms of both quantity and quality of water. This type of management allows these underground resources to be preserved for future generations. Conventional and isotope techniques allow information to be obtained on the most important hydrogeological parameters such as identification and evaluation of recharge and discharge area and rates, the available volume of groundwater to be estimated, hydrological interconnections between aquifers and surface waters, direction and velocity of groundwater flows, etc., which allow mathematical flow models to be established and validated. Mathematical models are indispensable tools for sustainable water resource management. The objective of the IAEA technical cooperation project RLA/8/031 was to contribute to improve the hydrogeological understanding of the aquifers through the use of isotopic and conventional techniques, with the final aim of improving groundwater resource management in several countries in Latin America. The present paper briefly summarizes the technical results obtained during the four years of the regional project [es

  2. Study of Neutron-Deficient $^{202-205}$Fr Isotopes with Collinear Resonance Ionization Spectroscopy

    CERN Document Server

    De Schepper, Stijn; Cocolios, Thomas; Budincevic, Ivan

    The scope of this master’s thesis is the study of neutron-deficient $^{202−205}$Fr isotopes. These isotopes are inside the neutron-deficient lead region, a region that has shown evidence of shape coexistence. For this thesis, this discussion is limited to the phenomenon where a low lying excited state has a different shape than the ground state. Shape coexistence is caused by intruder states. These are single-particle Shell Model states that are perturbed in energy due to the interaction with a deformed core. In the neutron-deficient lead region the main proton intruder orbit is the 3s$_{1/2}$orbit. When going towards more neutron-deficient isotopes, deformation increases. The $\\pi3s_{1/2}$orbit will rise in energy and will eventually become the ground state in odd- A bismuth (Z=83) isotopes. It is also observed in odd-A astatine (Z=85) isotopes, already in less neutron-deficient nuclei. The same phenomenon is expected to be present francium (Z=87) isotopes already at $^{199}$Fr. Although it is currently ...

  3. The study of the deuterium isotopic fractionation through the cell membrane of the plant

    International Nuclear Information System (INIS)

    Berdea, P.; Cuna, Stela; Deliu, C.

    2002-01-01

    The purpose of this study is to prove that there is a water deuterium isotope fractionation when the water passes through the cell membrane. The carrots (Daucus carota) were grown in vitro in a Murashige and Skoog mineral-salt medium and have been exposed to a water solution with a uniform isotopic content. After seven days the cell culture was filtered and the cell water was vacuum extracted. The water from aqueous solution and the cell water were analyzed for hydrogen by isotope ratio mass spectrometry. The procedure was repeated for 14 and 21 day old cell cultures. The measurements have revealed a water deuterium isotopic fractionation between extra-cellular water and cellular water. The deuterium content was found to be higher within the cells by 10 o / oo for non-embryonic cells and 13 o / oo for the embryonic cells. This fractionation is a non-evaporative fractionation between intracellular and extra-cellular water and it represents a new step in the overall fractionation of deuterium water in the plants. The existence of such isotopic fractionation through the cell membrane implies that the relationship between the deuterium content of cellulose nitrate in plant and meteoric water should be revised. Also, this finding is of interest for understanding the balance and dynamics of the hydrogen isotopes in the environment. (authors)

  4. Study of variations of stable isotopes in precipitation: case of Antananarivo

    International Nuclear Information System (INIS)

    Randrianarivola, M.

    2014-01-01

    The isotopic signature of precipitation is the input signal in any study of hydrological cycle. The scientific objective of this work is to better understand the isotopic variations in precipitation and identify their processes. We used the network of measurement GNIP (Global Network of Isotopes in Precipitation) in which data is acquired by the International Atomic Energy Agency through isotope hydrology laboratory at INSTN-Madagascar. Analyzes stable isotopes ( 18O and 2 H), were performed at a monthly time step. We were able to confirm the relative importance of different mechanisms governing the isotopic composition of precipitation. The spatial distribution of abundance ratios of Antananarivo rain is in fact dictated by the temperature which follow indirectly from the effects of altitude and seasonal variations. At the monthly scale, local meteoric water line δ 2 H versus δ 18 O shows the specificity of Antananarivo (deuterium excess of 17.5‰ ). Additionally, seasonal variations in precipitation is related to the temperature such that in summer (d=15‰) and winter (d=18‰) [fr

  5. Laser Spectroscopy Study on the Neutron-Rich and Neutron-Deficient Te Isotopes

    CERN Multimedia

    2002-01-01

    We propose to perform laser spectroscopy measurements on the Te isotopes. This will give access to fundamental properties of the ground and rather long-lived isomeric states such as the change in the mean square charge radius ($\\delta\\langle$r$^2_c\\rangle$) and the nuclear moments. For these medium-mass isotopes, at this moment the optical resolution obtained with RILIS is not high enough to perform isotope shift measurements. Thus we will use the COMPLIS experimental setup which allows Resonant Ionization Spectroscopy (RIS) on laser desorbed atoms. The 5p$^{4}$ $^{3}$P$_{2} \\rightarrow$ 5p$^{3}$ 6s $^{3}$S$_{1}$ and 5p$^{4}$ $^{3}$P$_{2} \\rightarrow$ 5p$^{3}$ 6s $^{5}$S$_{2}$ optical transitions have been used to perform, on the stable Te isotopes, the tests required by the INTC committee. For this purpose stable-ion sources have been built and Te isotopes have been delivered as stable beams by the injector coupled to the COMPLIS setup. ISOLDE offers the opportunity for studying the Te isotope series over a ...

  6. Determination of groundwater characteristics and water budget in the Edremit Plain by means of isotopes

    International Nuclear Information System (INIS)

    Onhon, E.

    1983-08-01

    Detailed field investigations with environmental isotopes (O-18, D, T, C-14 and C-13) have been conducted to study the replenishment process and flow dynamics of groundwater system in Edremit plain, which is an area of 200 m 2 size located in the eastern part of Turkey. Along with conventional hydrogeological and hydrochemical data collected from the study area, results of environmental isotopic analyses performed on water samples systematically collected from the area, enabled to delineate the source and origin of recharge to the shallow groundwater aquifers and as well provided information on various dynamic parameters of groundwater flow. In addition to basic flow dynamic characteristics of the shallow aquifer in the study area, environmental isotopes were used to investigate the hydraulic interconnections between deeper thermal groundwater system and the upper shallow aquifers. Results of all the environmental isotopic analyses and their interpretation are given

  7. Stable isotopes - separation and application

    International Nuclear Information System (INIS)

    Lockhart, I.M.

    1980-01-01

    In this review, methods used for the separation of stable isotopes ( 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, 18 O, 34 S) will be described. The synthesis of labelled compounds, techniques for detection and assay, and areas of application will also be discussed. Particular attention will be paid to the isotopes of carbon, nitrogen, and oxygen; to date, sulphur isotopes have only assumed a minor role. The field of deuterium chemistry is too extensive for adequate treatment; it will therefore be essentially excluded. (author)

  8. Origin of nanodiamonds from Allende constrained by statistical analysis of C isotopes from small clusters of acid residue by NanoSIMS

    Science.gov (United States)

    Lewis, Josiah B.; Floss, Christine; Gyngard, Frank

    2018-01-01

    Meteoritic nanodiamonds carry noble gases with anomalies in their stable isotopes that have drawn attention to their potentially presolar origin. Measurements of 12C/13C isotope ratios of presolar nanodiamonds are essential to understanding their origins, but bulk studies do not show notable deviations from the solar system 12C/13C ratio. We implemented a technique using secondary ion mass spectrometry with maximized spatial resolution to measure carbon isotopes in the smallest clusters of nanodiamonds possible. We measured C and Si from clusters containing as few as 1000 nanodiamonds, the smallest clusters of nanodiamonds measured to date by traditional mass spectrometry. This allowed us to investigate many possible complex compositions of the nanodiamonds, both through direct methods and statistical analysis of the distributions of observed isotopic ratios. Analysis of the breadth of distributions of carbon isotopic ratios for a number of ∼1000-nanodiamond aggregates indicates that the 12C/13C ratio may be drawn from multiple Gaussian distributions about different isotopic ratios, which implies the presence of presolar material. The mean isotopic ratio is consistent with the solar system value, so presolar components are required to be either low in concentration, or to have a mean ratio close to that of the solar system. Supernovae are likely candidates for the source of such a presolar component, although asymptotic giant branch stars are not excluded. A few aggregates show deviations from the mean 12C/13C ratio large enough to be borderline detections of enrichments in 13C. These could be caused by the presence of a small population of nanodiamonds formed from sources that produce extremely 13C-rich material, such as J-stars, novae, born-again asymptotic giant branch stars, or supernovae. Of these possible sources, only supernovae would account for the anomalous noble gases carried in the nanodiamonds.

  9. Isotope study of the groundwater of the Apodi Plateau

    International Nuclear Information System (INIS)

    Santiago, M.M.F.; Silva, C.M.S.V.; Frischkorn, H.; Manoel Filho, J.; Mendes Filho, J.

    2011-01-01

    Full text: The environmental isotopes oxygen-18 and deuterium, excellent natural tracers in hydrology, are used to characterize the groundwater stored in the Sedimentary Apodi Basin. They are originating from the Acu Sandstone Formation and from the limestone of the Jandaira Formation. These waters assist the needs from agricultural industry implanted on the top of the Apodi Plateau, responsible for the export of tropical horticulture products. This turns these waters a strategic reserve for the economic and social development of the area, and detailed knowledge of their storage and recharge conditions is necessary in order to maintain a sustainable exploration and an appropriate rational administration. With the objective of understanding the recharge mechanism and the interaction between the two aquifers, hydro chemical parameters, pH, and electric conductivity and isotopes oxygen-18 and deuterium were measured. Samples were collected in two periods, being one during the dry (set/09) and the other one at the beginning of the rainy period (jan/10). Values of δ 18 (in per mil) range from -3.5 to -2.0 in the Jandaira limestone waters, whereas they have an average of only -4.5 in Acu sandstone. Thus Jandaira values indicate the presence of recent waters and the values below - 4.0 in Acu waters indicate the presence of paleowaters, waters that should be considered as strategic reserve. The relationships between the two isotopes measured in the dry and rainy periods are described respectively by the equations δD = 4.0δO 18 - 10.5 and δD = 5.3δO 18 - 1.3. Comparing them to the classical World Meteoric Water Line (δD = 8δO 18 + 10, we identify that especially in the dry period evaporation and/or limestone dissolution play an important role. Electric conductivities of Jandaira waters range from 1000 to 3000μS/cm; waters from Acu sandstone are of lower salinity with a mean value of 500μS/cm. The relationship between the parameters oxygen-18, deuterium and electric

  10. The study of multicomponent separation of Xe isotope by centrifugal method

    International Nuclear Information System (INIS)

    Jinyan Wu; Fu Zhuge

    1996-01-01

    The element Xe has nine isotopes in nature, the separation performance of each component mutually affects the others, so the binary separation theory can't be employed to study the multicomponent separation. Especially, when the molecular wight of a certain component is in the middle of its isotope components, the effect of the others on this component must be considered. In this paper, first, the multicomponent separation of Xe isotopes in a gas centrifuge is studied, with the consideration of the effect of the concentration on the diffusion coefficient and average molecular weight. The multicomponent diffusion equations are solved by the finite difference method. Second, the enrichment of Xe isotopes in a cascade is studied. On the basis of the study of a gas centrifuge, the simplified separation equations of a gas centrifuge for cascade calculation are obtained. Furthermore, the complete equations of the cascade separation are established according to the conservation of mass of each component and solved by a numerical method. The study of this paper can be extended for other isotope separation calculations. (author)

  11. Study on the flow state of groundwater by isotope tracer

    International Nuclear Information System (INIS)

    Lin Tong; Chen Jiansheng; Chen Liang

    2008-01-01

    Radioisotope logging technique is an effective method to evaluate groundwater movement. Moving with the water, the isotope tracer distributes differently in different flow states. According to the depth and time distribution of radioactivity, flow state of the groundwater can be determined. In this paper, different flow states, i.e. laminar flow, turbulent flow and mixing flow, are analyzed, and calculation of the flow velocity is discussed. Also, we discuss how to distinguish the laminar flow part and turbulent part in a mixing flow. If one judges the flow state incorrectly, the error of flow velocity will be huge, hence the importance of flow state analysis. Finally, some problems in the practical projects and measuring methods are concluded. (authors)

  12. Isotopic techniques to study phosphorus cycling in soils

    International Nuclear Information System (INIS)

    Manjaiah, K.M.; Sreenivasa Chari, M.; Sachdev, P.; Sachdev, M.S.

    2008-01-01

    A sound understanding of phosphorus cycling in soil system is essential in order to manage this system in a sustainable manner. Phosphorus transformations are characterized by physico-chemical (sorption-desorption) and biological processes . The transformation rates need to be taken into account while developing nutrient management strategies for economical and sustainable production. One of the important tools and the method gaining popularity for determining the gross transformation rates of nutrients in the soil is the isotopic dilution technique. The major processes in the soil-plant system which determine the distribution and bioavailability of phosphorus in various inorganic and organic soil components consist of: (1) the dissolution of soil mineral phosphates, (2) retention of phosphorus by inorganic soil constituents, (3) decomposition of organic phosphorus contained in plant, animal and microbial detritus and (4) Immobilization of phosphorus via the soil microbial biomass and plan uptake

  13. Hydrogen-isotope motion in scandium studied by ultrasonic measurements

    International Nuclear Information System (INIS)

    Leisure, R.G.; Schwarz, R.B.; Migliori, A.; Torgeson, D.R.; Svare, I.

    1993-01-01

    Resonant ultrasound spectroscopy has been used to investigate ultrasonic attenuation in single crystals of Sc, ScH 0.25 , and ScD 0.18 over the temperature range of 10--300 K for frequencies near 1 MHz. Ultrasonic-attenuation peaks were observed in the samples containing H or D with the maximum attenuation occurring near 25 K for ScH 0.25 and near 50 K for ScD 0.18 . The general features of the data suggest that the motion reflected in the ultrasonic attenuation is closely related to the low-temperature motion seen in nulcear-magnetic-resonance spin-lattice-relaxation measurements. The ultrasonic results were fit with a two-level-system (TLS) model involving tunneling between highly asymmetric sites. The relaxation of the TLS was found to consist of two parts: a weakly temperature-dependent part, probably due to coupling to electrons; and a much more strongly temperature-dependent part, attributed to multiple-phonon processes. The strongly temperature-dependent part was almost two orders of magnitude faster in ScH 0.25 than in ScD 0.18 , in accordance with the idea that tunneling is involved in the motion. Surprisingly, the weakly temperature-dependent part was found to be about the same for the two isotopes. The asymmetries primarily responsible for coupling the TLS to the ultrasound are attributed to interactions between hydrogen ions that lie on adjacent c axes. The results are consistent with an isotope-independent strength for the coupling of the TLS to the ultrasound

  14. Study on influencing factors for hydrogen isotopic exchange

    International Nuclear Information System (INIS)

    Gu Mei; Liu Jun; Luo Yangming

    2013-01-01

    Background: Hydrogen-water catalytic exchange reaction offers an approach to hydrogen isotope separation, which can be applied in heavy water detritiation. Purpose: To optimize the operating condition for hydrogen-water catalytic exchange reaction, we analysed the influence of different factors on the transfer coefficient. Methods: In detail, the isotope exchange experiments of H-D system were carried out in a self-designed catalytic bed loaded with hydrophobic catalyst and hydrophilic packing with certain volume ratio. The experiments showed the changes of both the transfer coefficient and the pressure drop of column with the changing of the operational temperatures (29℃, 45℃, 60℃ and 75℃), the ratios of gas to liquid (0.58, 1.17, 2.65, 3.54) and the deuterium concentrations (5.05×10 -3 , 1.0144×10 -2 , 2.01×10 -2 ). Results: Results showed that 45℃ is the optimal temperature for operating. The transfer coefficient increases with the increasing of the ratio of gas to liquid in the ranges of 0.58 to 1.17 and 2.65 to 3.56, while decreases with the deuterium concentration increases from 5.05×10 -3 to 2.01×10 -2 . The pressure drop of column increases with increasing of gas flow rate. Conclusions: The experiment proves that the ratio of gas to liquid, the reaction temperature and the deuterium concentration are all important factors, which influence the transfer coefficient of deuterium obviously. The optimal operating condition for hydrogen-water catalytic exchange reaction are as follows: the temperature is 45℃, the ratio of gas to liquid is 3.56, and the deuterium concentration is 2.01×10 -2 . (authors)

  15. A STUDY ON CARBON ISOTOPE OF CO2 AND CH4 IN WESTERN DIENG PLATEU BY GAS CHROMATOGRAPHY- ISOTOPE RATIO MASS SPECTROMETER (GC-IRMS

    Directory of Open Access Journals (Sweden)

    Hanik Humaida

    2010-06-01

    Full Text Available The carbon isotope can be used to evaluate volcanism phenomenon of volcano. The study of carbon isotope of CO2 and CH4 was carried out in western Dieng Plateau by mass-spectrometer. Before analysis, sampel was separated by gas chromatography using a Porapak-Q column and a FID (Flame Ionization Detector detector. The gas was oxidized by copper oxide at 850oC before being ionized in mass-spectrometer for isotope analysis. The CO2 content in Candradimuka crater (-4.10 O/OO, indicated that the gas may be as volcanic gas. The other CO2 from Sumber and western Gua Jimat, had isotope value  of -10.05 and -12.07 O/OO, respectively, indicating contamination from crustal and subduction material. The carbon isotope of CH4 gas from Pancasan village was -63.42 O/OO, that may be categorized as biogenic gas.   Keywords: isotope, CO2, CH4, Dieng.

  16. Double and triple isotope gamma camera studies with energy selection after data collection

    International Nuclear Information System (INIS)

    Soussaline, F.; Raynaud, C.; Kacperek, A.; Kellershohn, C.; Sauce, M.; Zadje, C.

    1974-01-01

    A system comprising a Toshiba camera and a Informatek data processing system has been used to perform multiple isotope studies. A large window (30-550KeV) is used and the data can be manipulated after data collection, to form sets of dynamic frames for various energies. Linear combinations of matrices have been used to correct for scattering. Double isotope studies using 197Hg/198Au have been used to determine Hg renal uptake in man, and are compared to a previous technique requiring two separate data acquisitions. Animal (pig) renal experiments have been performed using 169 Yb/sup(99m)Tc/ 197 Hg. This pilot study gave good results and indicates the utility of the system for multiple isotope function studies in man [fr

  17. Stable isotope studies. Annual progress report, March 1, 1981-February 28, 1982

    International Nuclear Information System (INIS)

    Ishida, T.

    1981-01-01

    Our studies during the year consisted of cryogenic measurements of vapor pressure isotope effects (VPIE) in CHF 3 , CH 2 F 2 , CH 3 F, and ammonia, interpretations of the results of the VPIE studies of CHF 3 and CH 3 F by means of ab initio molecular orbital calculations and vibrational analyses, studies of nitrogen isotope fractionation by an exchange between nitric oxide and the liquid phase consisting of N 2 O 3 and N 2 O 4 under elevated pressures, an exploration of the concept of closed refluxer system for the Nitrox process for separating 15 N using a Fe(II)/Fe(III) system as reducing agent for nitric acid and the electrolysis for regeneration of Fe(II), and a theoretical study of approximation of the zero-point energy and its isotopic differences developed on the basis of Lanczos' tau-method

  18. Coordinated Oxygen Isotopic and Petrologic Studies of CAIS Record Varying Composition of Protosolar

    Science.gov (United States)

    Simon, Justin I.; Matzel, J. E. P.; Simon, S. B.; Weber, P. K.; Grossman, L.; Ross, D. K.; Hutcheon, I. D.

    2012-01-01

    Ca-, Al-rich inclusions (CAIs) record the O-isotope composition of Solar nebular gas from which they grew [1]. High spatial resolution O-isotope measurements afforded by ion microprobe analysis across the rims and margin of CAIs reveal systematic variations in (Delta)O-17 and suggest formation from a diversity of nebular environments [2-4]. This heterogeneity has been explained by isotopic mixing between the O-16-rich Solar reservoir [6] and a second O-16-poor reservoir (probably nebular gas) with a "planetary-like" isotopic composition [e.g., 1, 6-7], but the mechanism and location(s) where these events occur within the protoplanetary disk remain uncertain. The orientation of large and systematic variations in (Delta)O-17 reported by [3] for a compact Type A CAI from the Efremovka reduced CV3 chondrite differs dramatically from reports by [4] of a similar CAI, A37 from the Allende oxidized CV3 chondrite. Both studies conclude that CAIs were exposed to distinct, nebular O-isotope reservoirs, implying the transfer of CAIs among different settings within the protoplanetary disk [4]. To test this hypothesis further and the extent of intra-CAI O-isotopic variation, a pristine compact Type A CAI, Ef-1 from Efremovka, and a Type B2 CAI, TS4 from Allende were studied. Our new results are equally intriguing because, collectively, O-isotopic zoning patterns in the CAIs indicate a progressive and cyclic record. The results imply that CAIs were commonly exposed to multiple environments of distinct gas during their formation. Numerical models help constrain conditions and duration of these events.

  19. Studies of carbon--isotope fractionation. Annual progress report, December 1, 1974--November 30, 1975

    International Nuclear Information System (INIS)

    Ishida, T.

    1975-01-01

    The vapor pressure isotope effect of 13 C/ 12 C-substitution in CClF 3 was measured at temperatures between 169 0 and 206 0 K by means of cryogenic distillation. The 13 C/ 12 C-vapor pressure isotope effect in CHF 3 was also studied at temperatures between 161 0 and 205 0 K by a similar method. The construction of a cryostat has progressed as scheduled. The investigation of carbon isotope exchange equilibria between carbon dioxide and various carbamates dissolved in various organic solvents has continued. The five-stage system of Taylor-Ghate design was improved to shorten the transient time. A single stage apparatus was designed, built, and tested. These systems are used to measure the equilibrium constants and various phase equilibria involved in the carbon dioxide--carbamate system. The investigation of the explicit method of total isotope effect has made progress. A satisfactory approximation was found for the classical partition function of a Morse oscillator. The method gives a reasonable result at rho identical with 1 / 2 √(u/sub e//x/sub e/) greater than 1.5. The medium cluster approach was applied to isotopic methanes to investigate the effects of intermolecular distance and mutual orientations of molecules in the liquid upon vapor pressure isotope effect. It was found that all geometrical effects studied tend to vanish as the size of clusters is increased. Isotope effect in the zero-point energy shifts on condensation was calculated on the basis of London dispersion forces in liquid and a semi-empirical molecular orbital theory, and was favorably compared with experimental results

  20. Carbon, hydrogen oxygen isotope studies on imbedded old tree ring and paleoclimate reconstruction

    International Nuclear Information System (INIS)

    Sun Yanrong; Mu Zhiguo; Cui Haiting

    2002-01-01

    Tree ring is a kind of natural archives, on which the isotopic analysis is important to study global climate and environmental change. The authors mainly provide a comprehensive introduction to the fractionation models of carbon, hydrogen and oxygen isotope in plants, their research technique and the extract methods from cellulose. That results show isotopic tracer can record the message of climatic variation and has become a powerful tool for paleoclimate reconstruction and for the modern environment changing research. Especially studying on PAGES. the cellulose isotopic analyses of imbedded old tree ring have become the mainly quantitative means of environmental evolvement. In addition, China is a typical monsoon country, research in tree ring stable isotope seasonal variation can give a lot of important information on that. Up to now, the research techniques and works on tree ring in China are still in its earlier stage, and remain many limitations. It needs further accumulate basic research materials, intensity regional contrast and intercross studies on relative subjects

  1. Design study of fuel circulating system using Pd alloy membrane isotope separation method

    International Nuclear Information System (INIS)

    Naito, T.; Yamada, T.; Aizawa, T.; Kasahara, T.; Yamanaka, T.

    1981-01-01

    It is expected that the method of permeating through Pd-alloy membrances is effective for isotope separation and the refining of fuel gas. In this paper, the design study of the Fuel Circulating System (FCS) using Pb-alloy membranes is described. The study is mainly focused on the main vacuum, fuel gas refining, isotope separating, and tritium containment systems. In the fuel gas refining system, impurities are effectively removed by using Pd-alloy membranes. For the isotope separation system, the diffusion method through Pd-alloy membranes was adopted. From the standpoint of the safety and economy, a three-stage tritium containment system was adopted to control tritium release to the environment as low as possible. The principal conclusion drawn from the design study was as follows. In the FCS, while cryogenic distillation method appears to be practicable, Pd-alloy membrane method is attractive for isotope separation and the refining of fuel gas. For a large amount of tritium inventory, handling and control technologies should be completed by the experimental evaluation and development of the components and materials used for the FCS. A three-stage containment system was adopted to control tritium release to environment as low as possible. Consideration to prevent tritium escape will be necessary for fuel gas refiners and isotope separators. (Kato, T.)

  2. Studies of rotational structures in the neutron-rich niobium isotopes 101-103

    International Nuclear Information System (INIS)

    Paffrath, U.

    1989-08-01

    The aim of this thesis was to study rotational structures in the low-lying levels of the niobium isotopes 101, 102, and 103. This was performed at the recoil separator JOSEF of the Nuclear Research Facility Juelich by studies of the β-decays of the zirconium isotopes 101-103 into their niobium daughters. By γ-γ respectively X-γ coincidence measurements the already existing term schemes of the niobium isotopes should be verified respectively extended and by γ-γ angular-correlation measurements the rotational structures should be studied. The term schemes of the niobium isotopes 101 and 102 could be confirmed in the framework of the performed experiments while the level scheme of the 103 Nb could be essentially extended. From the X-γ coincidence measurement for a plurality of γ transitions the conversion coefficients and by this the dominant multipolarities could be determined. With these conversion coefficients then also the mixing parameters were calculated. These data together with the results from the γ-γ angular-correlation experiments led to a fixing concerning the spins and parities at a series of levels in all three niobium isotopes. (orig./HSI) [de

  3. Isotopes in environmental studies - Aquatic Forum 2004. Proceedings of an international conference. Unedited papers

    International Nuclear Information System (INIS)

    2006-01-01

    A better understanding of key processes in the aquatic environment, responsible for its future development and its protection, were at the forefront of the IAEA's International Conference on Isotopes in Environmental Studies - AQUATIC FORUM 2004 convened in Monaco from 25 to 29 October 2004, which was the most important gathering of the year of isotope environmental scientists. Over 320 experts from 60 IAEA Member States and 6 international organizations delivered 185 oral presentations in 6 plenary and 31 parallel sessions and made 130 poster presentations. The conference reviewed the present state of the art isotopic methods for investigation of the aquatic environment. The main conference subjects considered were: (i) behaviour, transport and distribution of isotopes in the aquatic environment; (ii) climate change studies using isotopic records in the marine environment; (iii) groundwater dynamics, modelling and management of freshwater sources; (iv) important global projects, such as WOCE, WOMARS, SHOTS, GEOTRACES; (v) joint IAEA-UNESCO submarine groundwater investigations in the Mediterranean Sea, the Southwest Atlantic and Pacific Oceans; (vi) new trends in radioecological investigations, concentrating on the protection of marine biota against radioactive contamination; (vii) transfers in analytical technologies from bulk analyses to particle and compound specific analyses of environmental samples; (viii) development of new isotopic techniques, such as AMS and ICPMS, and their successful applications in environmental studies; and many other exciting topics which were presented and discussed during the Conference. Four workshops were held simultaneously: - ATOMS-Med Workshop - development of a project proposal for oceanographic investigations in the Eastern Mediterranean. - El Nino - Research Co-ordination Meeting of the new IAEA Coordinated Research Project investigating climate change using isotopic records in the marine environment. - CELLAR Workshop

  4. Interference of scalp and skull with dynamic isotope studies of brain

    International Nuclear Information System (INIS)

    Oldendorf, W.H.

    1972-01-01

    The overlying scalp and skull create artifacts in external brain counting measurements in which isotope appears in these tissues. It is much less of a problem in dynamic studies since high levels of superficial isotope are not found in the first few seconds after introduction into the blood by any anatomic route. Diffusible tracers concentrate somewhat less in the scalp and skull than in the brain immediately after injection by any route. Nondiffusible tracers of low molecular weight attain a much higher concentration in the scalp than the brain only after about the first minute because of passage from plasma to scalp extracellular fluid. This equilibration does not occur in brain because of the blood-brain barrier. Scalp and skull thus create much less of a problem with brief dynamic studies than with chronic long-term studies. Some physical considerations of external collimation are discussed, and means are suggested to minimize superficial isotope contributions to brain counts. (U.S.)

  5. Strontium isotope study of coal utilization by-products interacting with environmental waters.

    Science.gov (United States)

    Spivak-Birndorf, Lev J; Stewart, Brian W; Capo, Rosemary C; Chapman, Elizabeth C; Schroeder, Karl T; Brubaker, Tonya M

    2012-01-01

    Sequential leaching experiments on coal utilization by-products (CUB) were coupled with chemical and strontium (Sr) isotopic analyses to better understand the influence of coal type and combustion processes on CUB properties and the release of elements during interaction with environmental waters during disposal. Class C fly ash tended to release the highest quantity of minor and trace elements-including alkaline earth elements, sodium, chromium, copper, manganese, lead, titanium, and zinc-during sequential extraction, with bottom ash yielding the lowest. Strontium isotope ratios ((87)Sr/(86)Sr) in bulk-CUB samples (total dissolution of CUB) are generally higher in class F ash than in class C ash. Bulk-CUB ratios appear to be controlled by the geologic source of the mineral matter in the feed coal, and by Sr added during desulfurization treatments. Leachates of the CUB generally have Sr isotope ratios that are different than the bulk value, demonstrating that Sr was not isotopically homogenized during combustion. Variations in the Sr isotopic composition of CUB leachates were correlated with mobility of several major and trace elements; the data suggest that arsenic and lead are held in phases that contain the more radiogenic (high-(87)Sr/(86)Sr) component. A changing Sr isotope ratio of CUB-interacting waters in a disposal environment could forecast the release of certain strongly bound elements of environmental concern. This study lays the groundwork for the application of Sr isotopes as an environmental tracer for CUB-water interaction. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Progresses in the stable isotope studies of microbial processes associated with wetland methane production

    International Nuclear Information System (INIS)

    Li Qing; Lin Guanghui

    2013-01-01

    Methane emissions from wetlands play a key role in regulating global atmospheric methane concentration, so better understanding of microbial processes for the methane emission in wetlands is critical for developing process models and reducing uncertainty in global methane emission inventory. In this review, we describe basic microbial processes for wetland methane production and then demonstrate how stable isotope fractionation and stable isotope probing can be used to investigate the mechanisms underlying different methanogenic pathways and to quantify microbial species involved in wetland methane production. When applying stable isotope technique to calculate contributions of different pathways to the total methane production in various wetlands, the technical challenge is how to determine isotopic fractionation factors for the acetate derived methane production and carbon dioxide derived methane production. Although the application of stable isotope probing techniques to study the actual functions of different microbial organisms to methane production process is significantly superior to the traditional molecular biology method, the combination of these two technologies will be crucial for direct linking of the microbial community and functional structure with the corresponding metabolic functions, and provide new ideas for future studies. (authors)

  7. The Use of Isotope Techniques to Separate of Hydrography Components. Case Study: Ankara-Guvenc Basin

    International Nuclear Information System (INIS)

    Tekeli, Y.I.; Sorman, A.U.; Sayin, M.

    2002-01-01

    In this research, a stable environmental isotope study was carried out from analysis of water samples collected from rainfall, runoff (total discharge), springs (subsurface flows), and wells (ground waters)in Ankara-Guevenc basin having a drainage area of about 16.125 km 2 between 1996-2000. The aim of the study was to investigate the rainfall-runoff relationship for the basin. Recorded total ten discharge hydrographs are separated to their components using stable isotopes (Oxygen-18, Deuterium) contents. Among these samples, unit hydrographs from two one-peak storm hydrographs were derived using both isotope and graphical methods, and the derived unit hydrographs values including peaks were compared. Peak values of 10 and 20 minutes unit hydrographs of the basin derived by using isotope method (Q p = 1322 1/s and Q p = 1327 l/s) are compared with those of graphical method (Q p = 1656 1/s, and Q p = 1250 1/s) using Barnes semi-log approach. It was found out that, the contribution of subsurface flow which is component of total discharge hydrograph and originating from various sub layers are important in the total flow of basin using isotope method of approach

  8. Revisiting climate changes. Isotope studies open scientific windows to the past

    International Nuclear Information System (INIS)

    Gibson, John; Aggarwal, Pradeep

    2001-01-01

    Earlier this year, scientists warned that 'an increasing body of observations gives a collective picture of a warming world and other changes in the climate system'. The conclusion came from the third assessment report of the Intergovernmental Panel on Climate Change (IPCC). Today, it is widely accepted that recent warning is largely a product of enhanced greenhouse gas concentrations in the atmosphere derived from post-industrial combustion of fossil fuels and biomass energy sources. However, great uncertainty remains regarding the causal relationships between specific parameters and climate phenomena, and regarding the impacts of climate change on the earth's water cycle. The science of climate change is dynamic. The IAEA contributes to studies via coordination of climate research, participation and support for international scientific programmes, and dissemination of isotope technology and applications. The third quadrennial scientific gathering on the use of isotopes for studying environmental change was held at the IAEA in Vienna 23-27 April 2001. The Conference - attended by 150 experts from 38 countries and seven international organizations - served as an important forum for presentation of results, discussion of ideas and concepts, establishment of international collaboration, and identification of avenues for future research. Selected highlights of issues discussed include: Isotopes are being used as validation tools for predicting impacts of deforestation of the Amazon Basin and for examining the past isotope signals of El Nino events; Isotope signatures in ice cores from low-latitude environments are showing similar temperature signals to polar ice cores,suggesting widespread (global) changes in the past; Isotopes are being used in the World Ocean Circulation Experiment to trace the movement, mixing and residence time of oceanic circulation patterns. Changes in ocean circulation are one of the most important factors controlling the variability of the

  9. Diminished excretion of polyamines from BHK-21/C13 cells exposed to methylglyoxal bis(guanylhydrazone).

    Science.gov (United States)

    Melvin, M A; Keir, H M

    1978-01-01

    Methylglyoxal bis(guanylhydrazone) (1,1'-[methylethanediylidine)dinitrilo]diguanidine) inhibited the growth of BHK-21/C13 cells in monolayer cultures. Accumulation of spermidine and spermine was inhibited, whereas the accumulation of putrescine was increased. The intracellular spermidine/spermine molar ratio decreased conly slightly after exposure of the cells to 20 micrometer-methylglyoxal bis(guanylhydrazone) for 1 day. Cells incubated in the presence of the drug released less polyamine into the culture medium that did control cells, the polyamine released consisting almost exclusively of spermidine, both free and as a conjugated form. PMID:697761

  10. Isotope effect study of κ-(BEDT-TTF)2Cu(NCS)2: Labeling in the anion

    International Nuclear Information System (INIS)

    Kini, A.M.; Wang, H.H.; Schlueter, J.A.

    1995-01-01

    Since the initial discovery of organic superconductivity in 1979, a large number of organic superconductors have now been synthesized. However, the mechanism of electron-pairing in these novel superconductors has remained largely unresolved. Isotope effect studies constitute an important experimental tool for the investigation of whether or not the electron-pairing mechanism in organic superconductors is phonon-mediated, as in conventional superconductors. Recent isotope effect studies in the authors' laboratory, involving seven different isotopically labeled BEDT-TTF (or ET) derivatives, have demonstrated the following: (1) intramolecular phonon modes involving C double-bond C and Csingle bondS stretching vibrations in the ET donor molecule are not the dominant mediators of electron-pairing, and (2) in κ-(ET) 2 Cu(NCS) 2 , there exist two competing isotope effects--a normal mass effect, i.e., lowering of T c upon isotopic labeling, when the ET molecular mass is increased by concurrent 13 C and 34 S labeling, in addition to an inverse isotope effect upon deuterium labeling in ET. It is of great interest to investigate if there is an isotope effect when the charge-compensating anions, which are also located within the non-conducting layer in the superconducting cation-radical salts, are isotopically labeled. The existence of an isotope effect when the anions are labeled would be indicative of electron-pairing with the mediation of vibrational frequencies associated with the anions. In this paper, the authors present the results of the first isotope effect study in which isotopic labeling in the anion portion of κ-(ET) 2 Cu(NCS) 2 is carried out. The authors find no isotope effect when the carbon and nitrogen atoms of the thiocyanate groups in the anion are replaced with 13 C and 15 N isotopes

  11. Isotope techniques in hydrological studies: application to Chacabuco-Polpaico basin

    International Nuclear Information System (INIS)

    Orphanopoulus Stehr, D.

    1982-01-01

    A hydrogeological study was carried out in a small alluvial valley, 45 kms. north of Santiago, Chile. Although the main economical activity is the agriculture, the valley only has small seasonal rivers. The irrigation water comes from a near basin through a channel of about 100 kms. and from the ground water. The study include aspects like: pumping tests evaluations, well stratigraphy, potentiometric surface fluctuation, water chemistry, stable isotopes and water balances. Isotopes, oxygen-18 and deuterium were used to identify the origin of the ground water in different sections of the valley and the importance of the infiltration. Also experiences were made to evaluate the evaporation of a small damm, using isotopes and the classical water balance methods. (O.S.)

  12. Groundwater problems studies in the Thar desert, India, using isotope techniques

    International Nuclear Information System (INIS)

    Navada, S.V.

    1999-01-01

    In groundwater management, particularly in arid regions like western Rajasthan, it is important to know the presence of modern recharge and to estimate the recharge rate to avoid over-exploitation of the groundwater resource. Isotopes can help to identify modern recharge and to estimate recharge rate to the aquifer. If modern recharge is absent, groundwater dating using radiocarbon could help to identify old groundwater or paleowaters. A number of isotope studies carried out in arid zones (particularly in the Sahara) have shown that the deep groundwater is generally very old. From these studies it was concluded that episodic large scale recharge corresponding to humid phases or pluvials occurred in these arid areas. The paper reviews our experiences on the application of isotope techniques in understanding groundwater recharge process in and western Rajasthan

  13. A study of Sr and Nd isotopic geology during anatexis in the area No.8411

    International Nuclear Information System (INIS)

    Ying Junlong

    1993-01-01

    An isotopic geology study in the area No.8411 indicates that the J 1-2 sandstone is lacustrine facies sediments mainly originated from Proterozoic old continental crust. Therefore, the magmatic rocks are derived from partial melting or remelting-contamination of Proterozoic old continents in the lower crust. The initial concentration of uranium is related with the magma contamination caused by anatexis in the old sialic crust. The isotopic compositions of both uranium minerals and magmatic rocks are relatively concordant. According to the results of this study, combined with petrology, mineralogy, isotopic evolution and REE contents, it is considered that uranium is derived from the deep source and uranium source rocks are Proterozoic old continents

  14. Field ionization mass spectrometry (FIMS) applied to tracer studies and isotope dilution analysis

    International Nuclear Information System (INIS)

    Anbar, M.; Heck, H.d'A.; McReynolds, J.H.; St John, G.A.

    1975-01-01

    The nonfragmenting nature of field ionization mass spectrometry makes it a preferred technique for the isotopic analysis of multilabeled organic compounds. The possibility of field ionization of nonvolatile thermolabile materials significantly extends the potential uses of this technique beyond those of conventional ionization methods. Multilabeled tracers may be studied in biological systems with a sensitivity comparable to that of radioactive tracers. Isotope dilution analysis may be performed reliably by this technique down to picogram levels. These techniques will be illustrated by a number of current studies using multilabeled metabolites and drugs. The scope and limitations of the methodology are discussed

  15. isotopic and hydrochemical studies on the groundwater of the eastern part of nile delta

    International Nuclear Information System (INIS)

    Nada, A.A.I.

    1984-01-01

    the present work deals with the study of trace elements, chemical composition and isotopic composition of oxygen and hydrogen in groundwater in the eastern part of the nile delta, surface water from the nile and ismaillia canal and sea water from the mediterranean sea and suez canal. this study involves chemical analysis for water samples and distribution of trace elements and major elements, some water-rock interactions, groundwater recharge relationships between surface and groundwater and some flow mechanism. the combination between isotopic composition and chemical composition of surface and groundwater

  16. Application of backflush and micro-flow techniques to the analysis of C5-C13 hydrocarbons in crude oils and its geochemical significance

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An Agilent 6890N GC equipped with both FID and Agilent 5975 MSD analyzer has been employed to analyze C5-C13 hydrocarbon fractions of crude oils. A technical combination of program temperature volatilizer injection, backflush and micro-flow controller afforded a fine separation of C5-C13 compounds on a PONA column with the heavy part of crude oils being cut off before entering the analytical column. Both GC-FID chromatogram and GC-MS mass chromatograrns (MID and full scan) could be obtained at the same time. The retension time differences of nC6-nC13 alkanes between GC and TIC were in the range of 0.02-0. 58 minutes. Totally 286 peaks have been assigned group compositions. Results on 8 typical oil samples from CNPC Key Laboratory Crude Oil Library showed that the characteristics of C6-C13 hydrocarbon group composition could be used in oil-oil correlation studies.

  17. The use of environmental isotopes on groundwater hydrology in the selected areas in Thailand

    International Nuclear Information System (INIS)

    Buapeng, S.

    1990-11-01

    A detailed environmental isotope investigation (using 0-18, H-2, H-3, C-14 and C-13 isotopes) has been carried out in a multi-layer aquifer system of the Chao-Phraya basin in Thailand. The main emphasis of the applied field research has been placed on the delineation of genesis of water and on studying the regional replenishment and flow characteristics of the groundwater in the lower Chao-Phraya basin (Bangkok Metropolitan Area). The results of isotope data gathered have been evaluated along with hydrochemical and basic hydrogeological data, to provide quantitative information on the replenishment characteristics of the groundwater and on the cause and processes involved in the increase of salinity being observed in the groundwater system of the Bangkok area. The report provides all the isotopic results and other relevant data together with interpretation and evaluation of the results. Refs, figs and tabs

  18. Stable isotope studies of nicotine kinetics and bioavailability

    International Nuclear Information System (INIS)

    Benowitz, N.L.; Jacob, P. III; Denaro, C.; Jenkins, R.

    1991-01-01

    The stable isotope-labeled compound 3',3'-dideuteronicotine was used to investigate the disposition kinetics of nicotine in smokers, the systemic absorption of nicotine from cigarette smoke, and the bioavailability of nicotine ingested as oral capsules. Blood levels of labeled nicotine could be measured for 9 hours after a 30-minute intravenous infusion. Analysis of disposition kinetics in 10 healthy men revealed a multiexponential decline after the end of an infusion, with an elimination half-life averaging 203 minutes. This half-life was longer than that previously reported, indicating the presence of a shallow elimination phase. Plasma clearance averaged 14.6 ml/min/kg. The average intake of nicotine per cigarette was 2.29 mg. A cigarette smoke-monitoring system that directly measured particulate matter in smoke was evaluated in these subjects. Total particulate matter, number of puffs on the cigarette, total puff volume, and time of puffing correlated with the intake of nicotine from smoking. The oral bioavailability of nicotine averaged 44%. This bioavailability is higher than expected based on the systemic clearance of nicotine and suggests that there may be significant extrahepatic metabolism of nicotine

  19. Stable-isotope studies of groundwaters in southeastern New Mexico

    International Nuclear Information System (INIS)

    Lambert, S.J.

    1987-01-01

    Oxygen-18/16 and deuterium/hydrogen ratio measurements have been made on groundwaters sampled according to specific field criteria applied during pump tests of the Rustler Formation in Nash Draw, a solution-subsidence valley west of the WIPP site in the northern Delaware Basin of southeastern New Mexico. Comparison of these data with similar measurements on other groundwaters from the northern Delaware Basin indicates two nonoverlapping populations of meteoric groundwaters. Most of the Rustler waters in Nash Draw and at the WIPP site and older waters from the eastern two-thirds of the Capitan Limestone constitute one population, while unconfined groundwaters originating as observable modern surface recharge to alluvium, the near-surface Rustler in southwestern Nash Draw, and the Capitan in the Guadalupe Mountains (Carlsbad Caverns) constitute the other. The isotopic distinction suggests that Rustler groundwater in most of Nash Draw and at the WIPP site is not receiving significant modern meteoric recharge. A likely explanation for this distinction is that meteoric recharge to most of the Rustler and Capitan took place in the geologic past under climatic conditions significantly different from the present. 25 refs., 4 figs., 2 tabs

  20. Stable isotope study of thermal and other waters in Fiji

    International Nuclear Information System (INIS)

    Cox, M.E.; Hulston, J.R.

    1980-01-01

    The O-18/O-16, D/H ratios and chloride concentrations of 79 thermal spring, subsurface, and surface waters from the two main islands of Fiji have been measured to determine the origin of the thermal waters and the characteristics of the geothermal activity. The meteoric waters generally fall along the Meteoric Water Line with a slope of 8, and best fit a line of this slope with a delta D intercept of +13 per mill. The delta O-18/delta D ratios of the thermal waters indicate low magnitude subsurface temperatures and a negligible enrichment in O-18. In one coastal locality in which higher temperature conditions exist, up to 50% seawater is shown to be mixing within the system, probably at shallow depths. The isotopic characteristics of the thermal waters reflect those of the local meteoric water, indicating localised recharge and an essentially meteoric origin. The effects of prevailing wind conditions and topography of these islands cause a depletion of deuterium in both precipitation and surface meteoric water from windward to leeward coasts (auth)

  1. Comparative study using different resins to determine thorium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Mychelle M.L.; Silva, Paulo S.C.; Maihara, Vera A., E-mail: my_linhares@yahoo.com.br, E-mail: pscsilva@ipen.br, E-mail: vmaihara@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Taddei, Maria Helena T., E-mail: mhtaddei@cnen.gov.br [Comissão Nacional de Energia Nuclear (LAPOC/CNEN), Poços de Caldas, MG (Brazil). Laboratório de Pocos de Caldas; Cheberle, Luan T.V., E-mail: luancheberle@gmail.com [Ambientis Radioproteção, Barueri, SP (Brazil)

    2017-07-01

    Thorium is a naturally occurring radioactive element that is widely distributed in the crust of the Earth. This element is very common in mineral formations in regions with high levels of natural radioactivity, therefore, its determination in environmental samples is important. Thorium isotopes ({sup 228}Th, {sup 230}Th, and {sup 232}Th) were determined in a reference material, the IAEA Soil 327 sample, to validate the two methods employed using different resins. The initial preparation with acid dissolution is the same to both, in the first is used anion exchange resin (DOWEX 1 x 2) and electrodeposition in silver planchets. And in the second method is used a specific chromatographic resin (TEVA) and cerium fluoride microprecipitation. At the end both analysis are quantified by alpha spectrometry. The two methods the results obtained were satisfactory for the reference material used, with relative error of less than 4% for {sup 228}Th, {sup 230}Th, and {sup 232}Th. The main differences found between them were spectrums resolutions, time and cost of analysis. (author)

  2. Oxygen isotope studies of the Salton Sea geothermal field

    International Nuclear Information System (INIS)

    Olson, E.R.

    1978-01-01

    Interbedded shales and sandstones were drilled to a depth of 1588 metres in Sinclair Number Four Well, Salton Sea Geothermal Field. Bottom hole temperatures are approximately 290 0 C. The oxygen dels of hydrothermal and detrital calcite have a systematic relationship at any depth in the geothermal reservoir. Typical values are: vein calcite, +6 0 / 00 ; calcite in white sandstone, +10 0 / 00 ; calcite in dark gray shale, +11 0 / 00 ; calcite in light gray shale, +17 0 / 00 ; calcite in red-brown shale, +20 0 / 00 . This succession represents decreasing water-rock interaction that is also indicated by the clay mineralogy of the shales. Permeability has a marked effect on the equilibration of water and rocks at any given temperature. Original differences in permeability have resulted in partial preservation of original detrital sedimentary compositions. The fluids in the Salton Sea Geothermal Field are probabaly partially evaporated Colorado River water, and their oxygen del values vary as much as 4 0 / 00 throughout the field. Truesdell's (1974) data suggest that dissolved salts may make the water oxygen activity del as much as 6 0 / 00 greater than the concentration del in the geothermal reservoir. Such an uncertainty is a serious impediment to precise isotope geothermometry in this system.(auth.)

  3. Experimental studies of the transfer phenomena of tritium in an isotope exchange column for tritium recovery

    International Nuclear Information System (INIS)

    Bornea, Anisia; Cristescu, Ion; Zamfirache, Marius; Varlam, Carmen

    2003-01-01

    To extract the tritium generated in the heavy water moderated power reactor, we have chosen the catalytic isotope exchange process in liquid phase combined with cryogenic distillation LPCE-CD. This paper presents the experimental studies of the catalytic isotope transfer of tritium. The catalytic isotope exchange process is performed in a column filled with successive layers of catalyst PT/C/PTFE and B7 type ordered package of phosphorous bronze. The catalyst and the package are manufactured in our institute and corresponding patents were issues. The catalyst consists of 95.5 wt.% PTFE, 4.1 wt. % carbon and 0.40 wt. % platinum and was made with 10'10'2 mm Raschig rings. The ordered package was consists of wire mesh phosphor bronze of 4'1 wire with a mesh size of 0.18 x 0.48 mm. The paper also presents the mathematical model which is used to evaluate the performance of the process. The mathematical model and the experimental data allowed determining two speed constants for isotope exchange process and for distillation process, respectively. By considering the values of these speed constants it is possible to improve the hydrophobic Pt catalyst and to design the H 2 /H 2 O isotopic exchange column package with this catalyst. (authors)

  4. Isotopic study of water exchange between atmosphere and biosphere at Changa Manga site in Pakistan

    International Nuclear Information System (INIS)

    Fazil, M.; Ali, M.; Latif, Z.; Butt, S.

    2012-01-01

    Study of water exchange between atmosphere and biosphere was initiated to understand the ties between these two spheres. Samples of leaves and stems of 23 woody plants along with soil from the surface and from the depth of 7 cm were collected from Changa Manga forest. Moisture content from these samples was extracted using the vacuum distillation method and analyzed for stable isotopes (/sup 18/O and /sup 2/H). Air moisture was also collected in the field. Isotopic data plotted long with the Local Meteoric Water Line (LMWL) indicates that /sup 18/O and /sup 2/H contents of moisture in the leaves of woody plants are higher than their respective stems. This behavior is due to the evaporative enrichment trend originating from the soil moisture in active root zone and also from the leaf surface. The stem samples did not show any significant variation in gamma /sup 18/O suggesting no significant evaporation from stems of big trees. Degree of enrichment of leave samples of woody plants indicated the species-specific effects in isotopes during transpiration. Pine and Eucalyptus leaves showed more variation in the isotopic contents as compared to other species. Temporal variations of /sup 18/O and /sup 2/H in the leaves indicated enriched isotopic values during hot and dry periods as compared to those during wet period (monsoon and winter rains) mainly due to higher transpiration rates at high temperature and low humidity. (orig./A.B.)

  5. Using stable isotopes of nitrogen and carbon to study seabird ecology: applications in the Mediterranean seabird community

    Directory of Open Access Journals (Sweden)

    Manuela G. Forero

    2003-07-01

    Full Text Available The application of the stable isotope technique to ecological studies is becoming increasingly widespread. In the case of seabirds, stable isotopes of nitrogen and carbon have been mainly used as dietary tracers. This approach relieson the fact that food web isotopic signatures are reflected in the tissues of the consumer. In addition to the study of trophic ecology, stable isotopes have been used to track the movement of seabirds across isotopic gradients, as individuals moving between isotopically distinct foodwebs can carry with them information on the location of previous feeding areas. Studies applying the stable isotope methodology to the study of seabird ecology show a clear evolution from broad and descriptive approaches to detailed and individual-based analyses. The purpose of this article is to show the different fields of application of stable isotopes to the study of the seabird ecology. Finally, we illustrate the utility of this technique by considering the particularities of the Mediterranean seabird community, suggesting different ecological questions and conservation problems that could be addressed by using the stable isotope approach in this community.

  6. Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence

    Energy Technology Data Exchange (ETDEWEB)

    Berhanu, Tesfaye A.; Erbland, Joseph; Savarino, Joël [Laboratoire de Glaciologie et Géophysique de l’Environnement, CNRS, F-38041 Grenoble (France); Univ. Grenoble Alpes, LGGE, F-38041 Grenoble (France); Meusinger, Carl; Johnson, Matthew S. [Copenhagen Center for Atmospheric Research (CCAR), Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Jost, Rémy [Laboratoire de Interdisciplinaire de Physique (LIPHY) Univ. de Grenoble, Grenoble (France); Bhattacharya, S. K. [Research Center for Environmental Changes, Academia Sinica, Nangang, Taipei 115, Taiwan (China)

    2014-06-28

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [“Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry,” J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate ({sup 15}N, {sup 17}O, and {sup 18}O) provide additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (δ{sup 15}N, δ{sup 18}O, and Δ{sup 17}O). From these measurements an average photolytic isotopic fractionation of {sup 15}ε = (−15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wavelengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of {sup 15}ε = (−47.9 ± 6.8)‰, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from −40 to −74.3‰. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of {sup 14}NO{sub 3}{sup −} and {sup 15}NO{sub 3}{sup −} in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying

  7. Enhancement of Palmarumycins C(12) and C(13) production in liquid culture of endophytic fungus Berkleasmium sp. Dzf12 after treatments with metal ions.

    Science.gov (United States)

    Mou, Yan; Luo, Haiyu; Mao, Ziling; Shan, Tijiang; Sun, Weibo; Zhou, Kaiyi; Zhou, Ligang

    2013-01-07

    The influences of eight metal ions (i.e., Na+, Ca2+, Ag+, Co2+, Cu2+, Al3+, Zn2+, and Mn4+) on mycelia growth and palmarumycins C(12) and C(13) production in liquid culture of the endophytic fungus Berkleasmium sp. Dzf12 were investigated. Three metal ions, Ca2+, Cu2+ and Al3+ were exhibited as the most effective to enhance mycelia growth and palmarumycin production. When calcium ion (Ca2+) was applied to the medium at 10.0 mmol/L on day 3, copper ion (Cu2+) to the medium at 1.0 mmol/L on day 3, aluminum ion (Al3+) to the medium at 2.0 mmol/L on day 6, the maximal yields of palmarumycins C(12) plus C(13) were obtained as 137.57 mg/L, 146.28 mg/L and 156.77 mg/L, which were 3.94-fold, 4.19-fold and 4.49-fold in comparison with that (34.91 mg/L) of the control, respectively. Al3+ favored palmarumycin C(12) production when its concentration was higher than 4 mmol/L. Ca2+ had an improving effect on mycelia growth of Berkleasmium sp. Dzf12. The combination effects of Ca2+, Cu2+ and Al3+ on palmarumycin C(13) production were further studied by employing a statistical method based on the central composite design (CCD) and response surface methodology (RSM). By solving the quadratic regression equation between palmarumycin C(13) and three metal ions, the optimal concentrations of Ca2+, Cu2+ and Al3+ in medium for palmarumycin C(13) production were determined as 7.58, 1.36 and 2.05 mmol/L, respectively. Under the optimum conditions, the predicted maximum palmarumycin C(13) yield reached 208.49 mg/L. By optimizing the combination of Ca2+, Cu2+ and Al3+ in medium, palmarumycin C(13) yield was increased to 203.85 mg/L, which was 6.00-fold in comparison with that (33.98 mg/L) in the original basal medium. The results indicate that appropriate metal ions (i.e., Ca2+, Cu2+ and Al3+) could enhance palmarumycin production. Application of the metal ions should be an effective strategy for palmarumycin production in liquid culture of the endophytic fungus Berkleasmium sp. Dzf12.

  8. β decay studies of n-rich Cs isotopes with the ISOLDE Decay Station

    Science.gov (United States)

    Lică, R.; Benzoni, G.; Morales, A. I.; Borge, M. J. G.; Fraile, L. M.; Mach, H.; Madurga, M.; Sotty, C.; Vedia, V.; De Witte, H.; Benito, J.; Berry, T.; Blasi, N.; Bracco, A.; Camera, F.; Ceruti, S.; Charviakova, V.; Cieplicka-Oryńczak, N.; Costache, C.; Crespi, F. C. L.; Creswell, J.; Fernández-Martínez, G.; Fynbo, H.; Greenlees, P.; Homm, I.; Huyse, M.; Jolie, J.; Karayonchev, V.; Köster, U.; Konki, J.; Kröll, T.; Kurcewicz, J.; Kurtukian-Nieto, T.; Lazarus, I.; Leoni, S.; Lund, M.; Marginean, N.; Marginean, R.; Mihai, C.; Mihai, R.; Negret, A.; Orduz, A.; Patyk, Z.; Pascu, S.; Pucknell, V.; Rahkila, P.; Regis, J. M.; Rotaru, F.; Saed-Sami, N.; Sánchez-Tembleque, V.; Stanoiu, M.; Tengblad, O.; Thuerauf, M.; Turturica, A.; Van Duppen, P.; Warr, N.

    2017-05-01

    Neutron-rich Ba isotopes are expected to exhibit octupolar correlations, reaching their maximum in isotopes around mass A = 146. The odd-A neutron-rich members of this isotopic chain show typical patterns related to non-axially symmetric shapes, which are however less marked compared to even-A ones, pointing to a major contribution from vibrations. In the present paper we present results from a recent study focused on 148-150Cs β-decay performed at the ISOLDE Decay Station equipped with fast-timing detectors. A detailed analysis of the measured decay half-lives and decay scheme of 149Ba is presented, giving a first insight in the structure of this neutron-rich nucleus.

  9. Feasibility study of plutonium isotopic analysis of resin beads by nondestructive gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Li, T.K.

    1985-01-01

    We have initiated a feasibility study on the use of nondestructive low-energy gamma-ray spectroscopy for plutonium isotopic analysis on resin beads. Seven resin bead samples were measured, with each sample containing an average of 9 μg of plutonium; the isotopic compositions of the samples varied over a wide range. The gamma-ray spectroscopy results, obtained from 4-h counting-time measurements, were compared with mass spectrometry results. The average ratios of gamma-ray spectroscopy to mass spectrometry were 1.014 +- 0.025 for 238 Pu/ 239 Pu, 0.996 +- 0.018 for 240 Pu/ 239 Pu, and 0.980 +- 0.038 for 241 Pu/ 239 Pu. The rapid, automated, and accurate nondestructive isotopic analysis of resin beads may be very useful to process technicians and International Atomic Energy Agency inspectors. 3 refs., 1 fig., 3 tabs

  10. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    2001-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surface has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen Isotopic defined beams from Pd (111) surface in the 40-400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one to the 5% D/(D+H) ratio - and for different incident energies. The beam was directed onto a single-crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to it. (authors)

  11. Studies of isotopic defined hydrogen beams scattering from Pd single-crystal surfaces

    International Nuclear Information System (INIS)

    Varlam, Mihai; Steflea, Dumitru

    1999-01-01

    An experimental investigation of hydrogen isotopes interaction with Pd single-crystal surfaces has been carried out using molecular beam technique. The energy dependence of the sticking probability and its relation with the trapping probability into the precursor state is studied by integrating the scattered angular distribution of hydrogen isotopic defined beams from Pd (111) surfaces in the 40 - 400 K surface temperature range. The dependence has been evaluated by defining hydrogen molecular beams with different isotopic concentration - from the natural one until 5% D/(D + H) and different incident energies and directed onto a single - crystal Pd (111) surface. In the paper, we report the experimental results and some considerations related to them. (authors)

  12. Lithium isotopic separation: preliminary studies; Separacao isotopica de litio: estudos preliminares

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Sandra Helena Goulart de

    1998-07-01

    In order to get the separation of natural isotopes of lithium by electrolytic amalgamation, an electrolytic cell with a confined mercury cathode was used to obtain data for the design of a separation stage. The initial work was followed by the design of a moving mercury cathode electrolytic cell and three experiments with six batches stages were performed for the determination of the elementary separation factor. The value obtained, 1.053, was ill agreement: with the specialized literature. It was verified in all experiments that the lithium - 6 isotope concentrated in the amalgam phase and that the lithium - 7 isotope concentrated in the aqueous phase. A stainless-steel cathode for the decomposition of the lithium amalgam and the selective desamalgamation were also studied. In view of the results obtained, a five stages continuous scheme was proposed. (author)

  13. Potential of Sr isotopic analysis in ceramic provenance studies: Characterisation of Chinese stonewares

    International Nuclear Information System (INIS)

    Li Baoping; Zhao Jianxin; Greig, Alan; Collerson, Kenneth D.; Zhuo Zhenxi; Feng Yuexin

    2005-01-01

    We compare the trace element and Sr isotopic compositions of stoneware bodies made in Yaozhou and Jizhou to characterise these Chinese archaeological ceramics and examine the potential of Sr isotopes in provenance studies. Element concentrations determined by ICP-MS achieve distinct characterisation for Jizhou samples due to their restricted variation, yet had limited success with Yaozhou wares because of their large variability. In contrast, 87 Sr/ 86 Sr ratios in Yaozhou samples have a very small variation and are all significantly lower than those of Jizhou samples, which show a large variation and cannot be well characterised with Sr isotopes. Geochemical interpretation reveals that 87 Sr/ 86 Sr ratios will have greater potential to characterise ceramics made of low Rb/Sr materials such as kaolin clay, yet will show larger variations in ceramics made of high Rb/Sr materials such as porcelain stone

  14. Isotopic Studies of O-O Bond Formation During Water Oxidation (SISGR)

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Justine P. [Johns Hopkins Univ., Baltimore, MD (United States)

    2015-03-03

    Isotopic Studies of O-O Bond Formation During Water Oxidation (SISGR) Research during the project period focused primarily on mechanisms of water oxidation by structurally defined transition metal complexes. Competitive oxygen isotope fractionation of water, mediated by oxidized precursors or reduced catalysts together with ceric, Ce(IV), ammonium nitrate in aqueous media, afforded oxygen-18 kinetic isotope effects (O-18 KIEs). Measurement, calculation, and interpretation of O-18 KIEs, described in the accompanying report has important ramifications for the production of electricity and solar hydrogen (as fuel). The catalysis division of BES has acknowledged that understanding mechanisms of transition metal catalyzed water oxidation has major ramifications, potentially leading to transformation of the global economy and natural environment in years to come. Yet, because of program restructuring and decreased availability of funds, it was recommended that the Solar Photochemistry sub-division of BES would be a more appropriate parent program for support of continued research.

  15. An isotope-aided study on the interaction of surface water and groundwater

    International Nuclear Information System (INIS)

    Ahn, Jong Sung; Kim, Jong Hoon; Yun, Si Tae; Jeong, Chan Ho; Kim, Kae Nam

    1987-12-01

    The interaction between surface water and groundwater was studied by isotope-aided techniques in the vicinity of the KAERI area. The understanding of surface water and groundwater flow systems and the analysis of geomaterials which provide the pathway of groundwater is important for the hydrogeological safety assessment of the radioactive waste disposal. The results of the analyses of environmental isotopes have shown that the shallow groundwater in this area was originated from the meteoric water which is infiltrated rapidly into the subsurface materials. The higher content of the environmental isotopes in some groundwater samples indicate that this anomalous values is attributed to impermeable, fine-grained materials. Also, the results of hydrochemical analyses of water samples indicate that shallow groundwater and precipitation are well mixed. (Author)

  16. Potential of Sr isotopic analysis in ceramic provenance studies: Characterisation of Chinese stonewares

    Energy Technology Data Exchange (ETDEWEB)

    Li Baoping [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia)]. E-mail: b.li@uq.edu.au; Zhao Jianxin [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia); Greig, Alan [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia); Collerson, Kenneth D. [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia); Zhuo Zhenxi [Shaanxi Provincial Institute of Archaeology, Xi' an 710054 (China); Feng Yuexin [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia)

    2005-11-15

    We compare the trace element and Sr isotopic compositions of stoneware bodies made in Yaozhou and Jizhou to characterise these Chinese archaeological ceramics and examine the potential of Sr isotopes in provenance studies. Element concentrations determined by ICP-MS achieve distinct characterisation for Jizhou samples due to their restricted variation, yet had limited success with Yaozhou wares because of their large variability. In contrast, {sup 87}Sr/{sup 86}Sr ratios in Yaozhou samples have a very small variation and are all significantly lower than those of Jizhou samples, which show a large variation and cannot be well characterised with Sr isotopes. Geochemical interpretation reveals that {sup 87}Sr/{sup 86}Sr ratios will have greater potential to characterise ceramics made of low Rb/Sr materials such as kaolin clay, yet will show larger variations in ceramics made of high Rb/Sr materials such as porcelain stone.

  17. Potential of Sr isotopic analysis in ceramic provenance studies: Characterisation of Chinese stonewares

    Science.gov (United States)

    Li, Bao-Ping; Zhao, Jian-Xin; Greig, Alan; Collerson, Kenneth D.; Zhuo, Zhen-Xi; Feng, Yue-Xin

    2005-11-01

    We compare the trace element and Sr isotopic compositions of stoneware bodies made in Yaozhou and Jizhou to characterise these Chinese archaeological ceramics and examine the potential of Sr isotopes in provenance studies. Element concentrations determined by ICP-MS achieve distinct characterisation for Jizhou samples due to their restricted variation, yet had limited success with Yaozhou wares because of their large variability. In contrast, 87Sr/86Sr ratios in Yaozhou samples have a very small variation and are all significantly lower than those of Jizhou samples, which show a large variation and cannot be well characterised with Sr isotopes. Geochemical interpretation reveals that 87Sr/86Sr ratios will have greater potential to characterise ceramics made of low Rb/Sr materials such as kaolin clay, yet will show larger variations in ceramics made of high Rb/Sr materials such as porcelain stone.

  18. Trace contaminants of agriculture, fisheries and food with particular reference to isotope studies

    International Nuclear Information System (INIS)

    Winteringham, F.P.W.

    1977-01-01

    Growing world population, industrilization and intensification of agricultural and fisheries practices have greatly increased the need during recent decades to protect the resources concerned, and the quality of food and agricultural environment. These trends have also resulted in a growing range of trace contaminants and excessive nutrient problems of agriculture and fisheries. Isotopic tracer and nuclear analytical techniques are powerful and often unique tools for the study and control of the problems, especially in relation to trace elements, nutrients and contaminants. In addition to the conventional use of radioactive and stable isotopes as tracers there appears to be considerable scope for the use of environmental or natural isotope ratio techniques and the use of labelled reagents and substrates as monitoring tools. Representative applications are described. (author)

  19. Isotope exchange study of the dissociation of metal-humic substance complexes

    International Nuclear Information System (INIS)

    Mizera, J.; Jansova, A.; Hvozdova, I.; Benes, P.; Novak, F.

    2003-01-01

    Isotope exchange was employed to study dissociation of metal cations from their complexes with humic substances (HS). Dissociation of cation from HS controls the rate of isotope exchange between two identical metal-HS solutions (but for the presence of a radiotracer) divided by a dialysis membrane. The rate of isotope exchange of Eu/ 152 Eu and Co/ 60 Co in the systems with various HS was monitored as a function of pH, ionic strength, and the degree of HS loading with metal. The apparent rate of Eu-HS dissociation was found to be enhanced by decreasing pH, increasing ionic strength, and increasing metal loading. Co-HS dissociation was too fast to be followed by the method. For interpretation of the experimental kinetic data, the multiple first order law has been applied. Based on the results, a concept of HS as a mixture of two types of binding sites is discussed. (author)

  20. Oxygen and hydrogen isotope studies of plutonic granitic rocks

    International Nuclear Information System (INIS)

    Taylor, H.P. Jr.

    1978-01-01

    The primary deltaD values of the biotites and hornblendes in granitic batholiths are remarkably constant at about -50 to -85, identical to the values in regional metamorphic rocks, marine sediments and greenstones, and most weathering products in temperate climates. Therefore the primary water in these igneous rocks is probably not 'juvenile', but is ultimately derived by dehydration and/or partial melting of the lower crust or subducted lithosphere. Most granitic rocks have delta 18 O = +7.0 to +10.0, probably indicating significant involvment of high- 18 O metasedimentary or altered volcanic rocks in the melting process; such an origin is demanded for many other granodiorites and tonalites that have delta 18 O = +10 to +13. Gigantic meteoric-hydrothermal convective circulation systems were established in the epizonal portions of all batholiths, locally producing very low delta 18 O values (particularly in feldspars) during subsolidus exchange. Some granitic plutons in such environments also were emplaced as low- 18 O magmas probably formed by melting or assimilation of hydrothermally altered roof rocks. However, the water/rock ratios were typically low enough that over wide areas the only evidence for meteoric water exchange in the batholiths is given by low D/H ratios (deltaK as low as -180); for example, because of latitudinal isotopic variations in meteoric waters, as one moves north through the Cordilleran batholiths of western North America an increasingly higher proportion of the granitic rocks have deltaD values lower than -120. The lowering of deltaD values commonly corelates with re-setting of K-Ar ages. (Auth.)

  1. Oxygen isotopic composition of mammal bones as a new tool for studying ratios of paleoenvironmental water and paleoclimates

    International Nuclear Information System (INIS)

    Longinelli, A.

    1984-04-01

    The purpose of this study is to try to establish quantitative relationships between the average oxygen isotopic composition of local meteoric water, the oxygen isotopic composition of mammal body water and the oxygen isotopic composition of phosphate in mammal bones. These relationships, after calibration of the method on living specimens, would allow quantitative paleoclimatological research based on the measurement of delta 18 O(PO 4 3- ) of fossil mammal bones

  2. Study of asymmetric fission yield behavior from neutron-deficient Hg isotope

    International Nuclear Information System (INIS)

    Perkasa, Y. S.; Waris, A.; Kurniadi, R.; Su'ud, Z.

    2014-01-01

    A study of asymmetric fission yield behavior from a neutron-deficient Hg isotope has been conducted. The fission yield calculation of the neutron-deficient Hg isotope using Brownian Metropolis shape had showed unusual result at decreasing energy. In this paper, this interesting feature will be validated by using nine degree of scission shapes parameterization from Brosa model that had been implemented in TALYS nuclear reaction code. This validation is intended to show agreement between both model and the experiment result. The expected result from these models considered to be different due to dynamical properties that implemented in both models

  3. An experimental study of odd mass promethium isotopes using proton stripping and pickup reactions

    International Nuclear Information System (INIS)

    Straume, O.

    1979-11-01

    Odd Pm isotopes have been studied by one proton pick-up and stripping reactions. Spin assignment and spectroscopic factors have been obtained for a number of energy levels. In the stripping reactions, the relative cross-sections have been measured with an unusually high precision by the use of a target of natural neodymium. The spectroscopic strengths have been extracted using standard distorted wave methods. The nuclear structures of these promethium isotopes fall into three categories. The spherical approach seems valid for 143 Pm and 145 Pm and the deformed regime covers 151 Pm and 153 Pm, while 147 Pm and 149 Pm remain as transitional nuclei. (Auth.)

  4. Environmental isotopic study of the Korama aquifers, south of Zinder (Niger)

    International Nuclear Information System (INIS)

    Zakara, Z.; Karbo, A.; Aranyossy, J.F.

    1993-01-01

    A first environmental isotope study has been carried out on the ''Korama'' aquifers located in the southern part of the city of Zinder (Niger). Preliminary interpretation confirms that most of the aquifers are presently recharged by direct infiltration of rainwater. Structural fractures seem to play an important role in the water circulation allowing vertical drainage of oldest water coming from deeper aquifers and facilitating the recharge by surface water in the prheatic zone. It does not appear any difference between the so-called ''superficial Korama'' and the ''Deep Korama'' aquifers on the basis of the isotopic compositions. (author). 11 refs, 7 figs, 2 tabs

  5. Isotopes in Hydrology, Marine Ecosystems and Climate Change Studies. Vol. I. Proceedings of an International Symposium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-07-15

    Humanity is facing many water related challenges, including access to safe water, pollution of continental and coastal waters and ocean acidification, as well as the growing impact of climate change on the hydrological cycle. Many countries are confronted by increasingly stressed water resources due to rapidly growing populations, increasing agricultural and energy production demands, industrial development, and pollution. The greatest issues of the 21st century, including competition for resources and possible related conflicts, may well focus on the role of water in food and energy security. For more than 50 years, the IAEA has played a key role in advancing and promoting the development and use of isotope techniques to address global environmental issues, such as water resources assessment and management, the study of marine ecosystems, and more recently the impact of climate change. This symposium was jointly organized by theWater Resources Programme and IAEA Environment Laboratories to commemorate the 50th anniversary of the establishment of the IAEA laboratory in the P rincipality of Monaco, and represented the 13th edition of the quadrennial symposium on isotope hydrology and water resources management, which has been regularly organized by the IAEA since 1963. The main objectives of the symposium were to review the state of the art in isotope hydrology, the use of isotopes in the study of climatic systems and in marine ecosystems and to outline recent developments in the application of isotope techniques, as well as to identify future trends and developments for research and applications. The contributions submitted by the authors are included in two volumes of proceedings with editorial corrections. These proceedings are intended to serve as an aid for those using isotopes for applied problems in hydrology as well as for the research community.

  6. Isotopes in Hydrology, Marine Ecosystems and Climate Change Studies, Vol. 2. Proceedings of the International Symposium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-07-15

    Humanity is facing many water related challenges, including access to safe water, pollution of continental and coastal waters and ocean acidification, as well as the growing impact of climate change on the hydrological cycle. Many countries are confronted by increasingly stressed water resources due to rapidly growing populations, increasing agricultural and energy production demands, industrial development, and pollution. The greatest issues of the 21st century, including competition for resources and possible related conflicts, may well focus on the role of water in food and energy security. For more than 50 years, the IAEA has played a key role in advancing and promoting the development and use of isotope techniques to address global environmental issues, such as water resources assessment and management, the study of marine ecosystems, and more recently the impact of climate change. This symposium was jointly organized by the Water Resources Programme and IAEA Environment Laboratories to commemorate the 50th anniversary of the establishment of the IAEA laboratory in the Principality of Monaco, and represented the 13th edition of the quadrennial symposium on isotope hydrology and water resources management, which has been regularly organized by the IAEA since 1963. The main objectives of the symposium were to review the state of the art in isotope hydrology, the use of isotopes in the study of climatic systems and in marine ecosystems and to outline recent developments in the application of isotope techniques, as well as to identify future trends and developments for research and applications. The contributions submitted by the authors are included in two volumes of proceedings with editorial corrections. These proceedings are intended to serve as an aid for those using isotopes for applied problems in hydrology as well as for the research community.

  7. International Symposium on Isotopes in Hydrology, Marine Ecosystems, and Climate Change Studies. Presentations

    International Nuclear Information System (INIS)

    2011-01-01

    Human activities have had a far-reaching impact on the aquatic environments - both marine and freshwater systems. The protection of these systems against further deterioration and the promotion of sustainable use are vital. In order to deepen understanding about the main processes affecting the present situation, as well as possible developments in the future, further investigation is required. The oceans play a major role in climate change, for example, and ocean acidification by increased CO2 release is one major threat to the world's oceans. Isotope methods can play a critical role in identifying and quantifying key processes within aquatic environments. Addressing the problems of global water resources has become a matter of urgency. Water resources are subject to multiple pressures for various reasons, including increasing populations, climate change, rising food and energy costs, the global economic crisis and pollutant loading. Isotope hydrology provides the unique and critical tools required to address complex water problems and helps managers and policy makers understand the closely intertwined relationship between water resources and the various pressures affecting them, as well as the issue of sustainability. The symposium will be an important forum for the exchange of knowledge on the present state of marine and freshwater environments, use of isotopes in water resources investigations and management, and climate change studies. The meeting will involve leading scientists in the field of climate change and hydrology, as well as representatives from other United Nations bodies and international organizations that focus on climate change and other important environmental issues. TOPICS: The role of isotopes in understanding and modelling climate change, marine ecosystems and the water cycle; Carbon dioxide sequestration and related aspects of the carbon cycle, such as ocean acidification; Isotopes in groundwater flow modelling for large aquifers

  8. Isotope aided studies of atmospheric carbon dioxide and other greenhouse gases. Phase II

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-01-01

    The substantial increase in atmospheric greenhouse gas concentrations and their role in global warming have become major concerns of world governments. Application of isotope techniques to label sources and sinks of CO{sub 2} and other greenhouse gases has emerged as a potentially powerful method for reducing uncertainties in the global CO{sub 2} budgets and for tracing pathways and interaction of terrestrial, oceanic, and atmospheric pools of carbon. As with CO{sub 2} concentration measurements, meaningful integration of isotopes in global models requires careful attention to quality assurance, quality control and inter-comparability of measurements made by a number of networks and laboratories. To support improvements in isotope measurement capabilities, the IAEA began implementing Co-ordinated Research Projects (CRPs) in 1992. The first project, entitled Isotope Variations of Carbon Dioxide and other Trace Gases in the Atmosphere, was implemented from 1992 to 1994. A significant contribution was made towards a better understanding of the global carbon cycle and especially of the sources and sinks of carbon with data on the {sup 14}C and {sup 13}C content of atmospheric CO{sub 2}, pointing to a better understanding of the problem of the 'missing sink' in the global carbon cycle. Important methodological developments in the field of high precision stable isotope mass spectrometry and improved data acquisition procedures emerged from work carried out within the framework of this programme. The development of pressurized gas standards and planning for an associated interlaboratory calibration were initiated. Due to the good progress and long standing nature of the required work a second CRP was initiated and implemented from 1996 to 1999. It was entitled Isotope aided Studies of Atmospheric Carbon Dioxide and Other Trace Gases - Phase II, to document the close relationship of both programmes. This publication provides an overview of the scientific outcomes of the

  9. Isotope aided studies of atmospheric carbon dioxide and other greenhouse gases. Phase II

    International Nuclear Information System (INIS)

    2002-01-01

    The substantial increase in atmospheric greenhouse gas concentrations and their role in global warming have become major concerns of world governments. Application of isotope techniques to label sources and sinks of CO 2 and other greenhouse gases has emerged as a potentially powerful method for reducing uncertainties in the global CO 2 budgets and for tracing pathways and interaction of terrestrial, oceanic, and atmospheric pools of carbon. As with CO 2 concentration measurements, meaningful integration of isotopes in global models requires careful attention to quality assurance, quality control and inter-comparability of measurements made by a number of networks and laboratories. To support improvements in isotope measurement capabilities, the IAEA began implementing Co-ordinated Research Projects (CRPs) in 1992. The first project, entitled Isotope Variations of Carbon Dioxide and other Trace Gases in the Atmosphere, was implemented from 1992 to 1994. A significant contribution was made towards a better understanding of the global carbon cycle and especially of the sources and sinks of carbon with data on the 14 C and 13 C content of atmospheric CO 2 , pointing to a better understanding of the problem of the 'missing sink' in the global carbon cycle. Important methodological developments in the field of high precision stable isotope mass spectrometry and improved data acquisition procedures emerged from work carried out within the framework of this programme. The development of pressurized gas standards and planning for an associated interlaboratory calibration were initiated. Due to the good progress and long standing nature of the required work a second CRP was initiated and implemented from 1996 to 1999. It was entitled Isotope aided Studies of Atmospheric Carbon Dioxide and Other Trace Gases - Phase II, to document the close relationship of both programmes. This publication provides an overview of the scientific outcomes of the studies conducted within Phase

  10. ISOTOPES, PLANTS, AND RESERVOIR EFFECTS : CASE STUDY FROM THE CASPIAN STEPPE BRONZE AGE

    NARCIS (Netherlands)

    Shishlina, N.; Zazovskaya, E.; van der Plicht, J.; Sevastyanov, V.; Boaretto, E.; Rebollo Franco, N.R.

    2012-01-01

    Bronze Age human and animal bone collagen from several steppe Bronze Age cultures (i.e. Early Catacomb, East and West Manych Catacomb, and Lola cultures) shows large variations in delta C-13 and delta N-15 values. In general, we observed that the older the sample, the lower the delta C-13 and delta

  11. Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web

    International Nuclear Information System (INIS)

    Kwon, Sae Yun; Blum, Joel D.; Nadelhoffer, Knute J.; Timothy Dvonch, J.; Tsui, Martin Tsz-Ki

    2015-01-01

    Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ 202 Hg and Δ 199 Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ 202 Hg and Δ 199 Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ 202 Hg and Δ 199 Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ 199 Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~ 20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ 202 Hg and Δ 199 Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ 199 Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ 199 Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative importance of MMHg sources and complex Hg transfer

  12. Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Sae Yun, E-mail: saeyunk@umich.edu [Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave, Ann Arbor, MI 48109 (United States); Blum, Joel D. [Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave, Ann Arbor, MI 48109 (United States); Department of Ecology and Evolutionary Biology, University of Michigan, 830 N. University Ave, Ann Arbor, MI 48109 (United States); Nadelhoffer, Knute J. [Department of Ecology and Evolutionary Biology, University of Michigan, 830 N. University Ave, Ann Arbor, MI 48109 (United States); Timothy Dvonch, J. [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Tsui, Martin Tsz-Ki [Department of Biology, University of North Carolina at Greensboro, 321 McIver Street, Greensboro, NC 27402 (United States)

    2015-11-01

    Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ{sup 202}Hg and Δ{sup 199}Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ{sup 202}Hg and Δ{sup 199}Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ{sup 202}Hg and Δ{sup 199}Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ{sup 199}Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~ 20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ{sup 202}Hg and Δ{sup 199}Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ{sup 199}Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ{sup 199}Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative

  13. Comparative study on bromide and iodide ion-isotopic exchange reactions using strongly basic anion exchange resin Duolite A-113

    International Nuclear Information System (INIS)

    Lokhande, R.S.; Dole, M.H.; Singare, P.U.

    2006-01-01

    Kinetics of ion-isotopic exchange reaction was studied using industrial grade ion exchange resin Duolite A-113. The radioactive isotopes 131 I and 82 Br were used to trace the ion-isotopic exchange reaction. The experiments were performed in the temperature range of 26.0degC to 43.0degC and the concentration of external ionic solution varying from 0.005 M to 0.100 M. For bromide ion-isotopic exchange reaction, the calculated values of specific reaction rate, initial rate of bromide ion exchange, and amount of bromide ions exchanged were obtained higher than that for iodide ion-isotopic exchange reaction under identical experimental conditions. The observed variation in the results for two ion-isotopic exchange reactions was due to the difference in the ionic size of bromide and iodide ions. (author)

  14. An isotopic study of nitrate pollution of groundwater in Victoria, Australia

    International Nuclear Information System (INIS)

    Changkakoti, A.; Lawrence, C.R.; Cherstnova, L.; Chalk, P.; Krouse, H.R.

    1997-01-01

    Nitrate in groundwater can be a hard to human and animal health and contribute to the development of algal blooms and subsequent eutrophication of wetlands. Its presence is widespread throughout Australia and its levels overall appear to be increasing. A variety of sources of nitrate contamination of groundwater are known. These include nitrogen fixing plants, termites, animal wastes, industrial wastes, domestic wastes, sewage and fertilizers. In Victoria, nitrate-rich groundwaters have been reported from a number of localities, some of which include Colac, Nepean Peninsula, Shepparton, Deer Park, Benalla and Winchelsea. A multi-isotope method was developed to determine the probable source of pollution in these localities. Changes in the natural abundance ratio of the stable isotopes of nitrogen, 14 N and 15 N, and the differences in the isotopic ratios ( 15 N/ 14 N) of nitrate from various sources, form the basis of the N-isotope technique for source identification. Differences in the isotopic ratios of oxygen ( 18 O/ 16 O) and hydrogen (D/H) of polluted and unpolluted waters form the basis for the oxygen and hydrogen isotope technique to investigate pollution problems of groundwater. Sites which included clover, industrial wastes, animal and human wastes and fertilized sources, were selected after reviewing existing databases on nitrate concentration, earlier reports and access to a suitable network of bores for collecting reliable samples. The nitrate concentration ranged from less than 1 mg/L to in excess of 22.0 mg/L, whilst ammonium levels in most samples were less than 1 mg/L. The δ 15 N values of the various source types ranged from 8.8 to 19.0 per mill (pastures). The δ 18 O and δD data indicate seawater incursion in the coastal areas of the Nepean Peninsular. The results agree with published data on similar sources from elsewhere in the world, and indicate the potential use of this methodology in groundwater pollution studies in Australia

  15. Study of isotopic desequilibrium of natural radioactive series in granitic environment: Pluton of El Berrocal (Toledo)

    International Nuclear Information System (INIS)

    Hernandez Benitez, A.

    1994-01-01

    This report summarizes the work funded by European Communities with contract '' The Berrocal project: characterization and validation of natural radionuclide migration processes under real conditions in a fissured granitic environment''. The author takes into account the following aspects in his study: isotope of natural radionuclides, sampling methods, analytic methodology and geological characteristics of the area

  16. Isotope Fractionation in Methane Reactions Studied by Gas Chromatography and Liquid Scintillation

    DEFF Research Database (Denmark)

    Andersen, Bertel Lohmann; Bidoglio, G.; Leip, A.

    1997-01-01

    Determination of C-14-marked methane by gas chromatography and liquid scintillation counting is shown to be useful in studies of isotope effects. Data on the specific activity is used to separate the contributions of (CH4)-C-14, and (CH4)-C-12 to the gas-chromatographic peak area. As an application...

  17. A study of oxygen isotopic fractionation during bio-induced calcite precipitation in eutrophic Baldeggersee, Switzerland

    NARCIS (Netherlands)

    Teranes, J.L.; McKenzie, J.A.; Bernasconi, S.M.; Lotter, A.F.; Sturm, M.

    1999-01-01

    Abstract—In order to better understand environmental factors controlling oxygen isotope shifts in autochthonous lacustrine carbonate sequences, we undertook an extensive one-year study (March, 1995 to February, 1996) of water-column chemistry and daily sediment trap material from a small lake in

  18. Isotopic studies of beach rock carbonates from Konkan, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, B.; Rajamanickam, G.V.; Gujar, A.R.

    .7% (PDB) and delta sup(18)O signatures lie in a narrow range of +27.5 to +28.6% (SMOW), respectively. Isotopic data obtained in this study show that cementation of beach rock carbonates might have taken place in a shallow vadose zone. The large variations...

  19. Studies on the magnetic after-effect of hydrogen isotopes in hexagonal crystals

    International Nuclear Information System (INIS)

    Herbst, G.

    1979-01-01

    The behaviour of hydrogen isotopes in hexagonal gadolinium, in intermetallic compounds of the RECo 5 type (RE = rare earth metal), and in cobalt alloys with small concentrations of alloyed impurity atoms was studied using the magnetic after-effect method in the temperature range between 4.2 K and 300 K. (orig./WBU) [de

  20. Silicon isotope study of thermal springs in Jiaodong Region,Shandong Province

    Institute of Scientific and Technical Information of China (English)

    徐跃通; 李红梅; 冯海霞; 周晨; 吴元芳; 张邦花

    2001-01-01

    Based on δ30Si and δ32Si isotope geochemistry, the origin and evolutionary mechanism of thermal springs in Jiaodong region are studied. The mean value of δ30Si of dissolved silica of thermal spring water in Jiaodong is 0.1‰. Thermal spring water ages using δ32Si dating method range from 387a to 965a.

  1. Microscopic insight in the study of yrast bands in selenium isotopes

    Indian Academy of Sciences (India)

    the rotational-like energy spacings of the yrast states with I≥6. ... even–even selenium isotopes, the study of structure of high spin states through mea- ... calculations with this model can achieve a comparable quality to the large-scale ... model in that the PSM uses the angular momentum projected states as the basis.

  2. Microscopic study of positive-parity yrast bands of Th isotopes

    Indian Academy of Sciences (India)

    tor arrays. Thorium is one of the isotopic mass chains that has been studied. The level ... the valence space and np-interaction in SOP orbits plays a crucial role in determining the ..... parameters suggested by Rozmej [37] in the actinide region.

  3. A new cascade method for studying isotope effect in chemical exchange system without valance change

    International Nuclear Information System (INIS)

    Wen Xiaoning; Luo Wenzong

    1987-01-01

    A new cascade method for studying isotope effect in chemical exchange system without valance change is developed and described. This method is simple to use and consumes less extractant as compared with the commonly used Woodward method. It is also convenient for unstable systems

  4. The stable isotopes in the hydrology studies at Raureni-Valcea area

    International Nuclear Information System (INIS)

    Costinel, D.; Vremera, R.; Faurescu, I.; Grecu, V. V.; Cuna, S.

    2009-01-01

    At present the hydrology and the climate studies are will continue to be joined to human activities. Observing differences of the stable isotopic concentration ratios informs us about certain geochemical or hydrological processes that took place. The isotopic composition of oxygen and hydrogen in rainwater varies with latitude, altitude, climate and time of the year. This methodology is an important tool in studying groundwater movement or freshwater origin. This study demonstrated the utility of the Continuous Flow - Isotope Ratio Mass Spectrometry method for measuring natural variation of the occurring isotopes of hydrogen ( 2 H) and oxygen ( 18 O) in meteoric waters. We continue until now (September 2009) the last work in which we measured the variation of δ 18 O and δ 2 D values from precipitation fallen in Raureni-Valcea area between May-December 2007 and September 2008-March, together with the δ 18 O and δ 2 D values from the Bistrita river. For this area the local Meteoric Water Line was reported and the variation of δ 18 O and δ 2 D values was correlated with the temperature and humidity in the same period. (authors)

  5. Shape coexistence in the lightest Tl isotopes studied by laser spectroscopy

    CERN Multimedia

    Herfurth, F; Antalic, S; Darby, I G; Venhart, M; Flanagan, K; Veselsky, M; Blaum, K; Radulov, D P; Beck, D; Kowalska, M; Schwarz, S; Chapman, R; Diriken, J V J; Lane, J; Rosenbusch, M

    This proposal aims at atomic spectroscopy studies of the very neutron-deficient isotopes $^{178-187}$Tl, at and far beyond the region of the neutron mid-shell at N=104, in which shape coexistence phenomena were investigated so far by particle and $\\gamma$-ray spectroscopy methods only. Our motivation for this proposal is as follows : \\\\\\\\ -These studies will provide direct data on magnetic dipole moment, spin, charge radii and deformations of these isotopes. The results will form a stringent test for our current understanding of the shape coexistence phenomena in the vicinity of the neutron mid-shell at N=104, where the relevant effects are expected to be the strongest (cf.shape staggering in the isotopes $^{181,183,185}$Hg). \\\\-The knowledge of the structure (configuration, spin, deformation) and whether one or two $\\beta$-decaying isomers are present in the parent isotopes $^{178,180,182}$Tl are crucial for understanding of the results of our recent studies of $\\beta$-delayed fission in the lightest thalli...

  6. Aragonite-Calcite Inversion During Biogenic Carbonate Sampling: Considerations for Interpreting Isotopic Measurements in Paleoclimate Studies

    Science.gov (United States)

    Waite, A. J.; Swart, P. K.

    2011-12-01

    As aragonite is the metastable polymorph of calcium carbonate, it lends itself to monotropic inversion to the more stable polymorph, calcite. This inversion is possible through an increase in the temperature and pressure conditions to which the sample is exposed and, although first noted nearly a century ago, has been primarily discussed in the context of sample roasting prior to analyses in paleoclimatological studies. Over the last several decades, however, researchers have found evidence to suggest that the friction associated with the sampling of biogenic carbonates via milling/drilling also induces inversion. Furthermore, this inversion may be associated with a shift in measured oxygen isotopic values and ultimately have significant implications for the interpretation of paleoclimatic reconstructions. Despite this, the isotopic heterogeneity of biogenic aragonite skeletons makes the effects of inversion challenging to test and the subject remains underrepresented in the literature. Here we present a first order study into the effects of milling on both the mineralogy and isotopic compositions measured in sclerosponges, corals, and molluscs. X-Ray diffraction analysis of samples hand ground with a mortar and pestle reveal 100% aragonitic skeletons. Conversely, samples milled with a computerized micromill show measurable inversion to calcite. On average, percent inversion of aragonite to calcite for individual specimens was 15% for sclerosponges, 16% for corals, and 9% for molluscs. Isotopic data from these specimens show that the higher the percentage of aragonite inverted to calcite, the more depleted the measured oxygen isotopic values. In the largest of the datasets (sclerosponges), it is evident that the range of oxygen isotope values from milled samples (-0.02 to +0.84%) exceeds the range in values for those samples which were hand ground and showed no inversion (+0.53 to +0.90%). This, coupled with the strong correlation between the two variables

  7. Polyamine replacement by magnesium ions in BHK-21/C13 cells

    Science.gov (United States)

    Melvin, Maureen A. L.; Keir, Hamish M.

    1979-01-01

    Cultures of BHK-21/C13 cells, whose growth was inhibited by deprivation of serum, were stimulated to grow by addition of serum to the culture medium. Addition of MgCl2 to the medium, to increase the concentration of Mg2+ ions by 15mm, 30min before addition of serum, had no effect on the stimulation of cell growth, but inhibited the accumulation of cellular spermidine, so that the spermidine/spermine molar ratio was lower in these cultures than in cultures that had received no additional cations. The increase in the activity of ornithine decarboxylase that occurs 4–5h after serum `step-up' was substantially diminished by increasing the concentration of Mg2+ ions, but not of Na+ or K+ ions, in the medium by 30mm, 30min before addition of serum, and this inhibition was maintained for at least 24h. Methylglyoxal bis(guanylhydrazone), added to serum-deprived cultures to a concentration of 20μm, 30min before addition of serum, severely inhibited the increase in cell growth. The inhibitory effects of the drug were prevented by simultaneous addition of spermidine to the medium (to 100μm), and were partly prevented by the simultaneous addition of Mg2+ ions (to 30mm). Mg2+ ions were particularly effective in overcoming the inhibitory effect of methylglyoxal bis(guanylhydrazone) on the synthesis of DNA. Thus although a certain lack of specificity for cations exists in BHK-21/C13 cells, in that Mg2+ ions can be substituted for polyamines, particularly spermidine, to some extent, there are cellular processes for which the requirement for polyamines as cations is specific. PMID:444220

  8. Pan-European C13 values of air and organic matter from forest ecosystems

    Czech Academy of Sciences Publication Activity Database

    Hemming, D.; Yakir, D.; Ambus, P.; Aurela, M.; Besson, C.; Black, K.; Buchmann, N.; Burlett, R.; Cescatti, A.; Clement, R.; Gross, P.; Granier, A.; Grunwald, T.; Havránková, Kateřina; Janouš, Dalibor; Janssens, I.; Knohl, A.; Kostner, B.; Kowalski, A.; Laurila, T.; Mata, C.; Marcolla, B.; Matteucci, G.; Moncrieff, J.; Moors, E.; Osbome, B.; Pereira, J.S.; Pihlatie, M.; Pilegaard, K.; Ponti, F.; Rosová, Zuzana; Rossi, F.; Scartazza, A.; Vesela, T.

    2005-01-01

    Roč. 11, č. 7 (2005), s. 1065-1093 ISSN 1354-1013 Institutional research plan: CEZ:AV0Z60870520 Keywords : CO2 fluxes * ecosystem carbon budget * stable isotopes Subject RIV: GK - Forestry Impact factor: 4.075, year: 2005

  9. Verification of strontium isotopes and its possible source in Indian basmati rice for geographical authentication study

    International Nuclear Information System (INIS)

    Lagad, Rupali A.; Rai, Vinai K.; Singh, Sunil K.

    2015-01-01

    Due to globalization of food and agriculture product's market, there is increasing awareness of safety and authenticity of the food products. Consumers continuously demand the reassurance of origin and content of their foods. Hence safety and authenticity of food has been a growing analytical challenge. Basmati rice, the unique aromatic quality rice and a nature's gift to Indian sub-continent is produced and consumed on a large scale. Due to its profitable market as well as great demand overseas true Basmati rice market is facing unfair competition by unscrupulous producers for profit. Very few researches for geographical authentication are available for Indian basmati rice. Sr isotope composition of rice could be used as a geographical source indicator; however, little information is available on the possible source (lithogenic, biogenic, silicate, carbonate) of Sr in Rice or any other food stuff for tracing the geographical origin using Strontium isotopes as tracer. Hence in order to determine suitability of strontium isotopes as tracer and its possible source in rice for geographical authentication study, strontium isotope signature study of authentic Indian Basmati rice along with in situ soil and water of that region have been carried out

  10. Use of environmental isotopes in hydrogeological studies in Kedah and Perlis, Malaysia

    International Nuclear Information System (INIS)

    Daud bin Mohamad.

    1981-01-01

    A preliminary study of the isotope hydrology of the Kedah and Perlis area was undertaken under the RCA programme. This project is an attempt at elucidating the mechanism of recharge, origin, area of recharge and dating of groundwater system in the area. The results show that all groundwater samples in the area vary within a narrow range for 18 0 (-7.58 to -5.06%) while 2 H ranges from -50.3 to -35.1%. The mean isotopic composition of precipitation collected at Alor Star meteorological station fall within the range of variation of the Kedah/Perlis groundwaters. In the southern part of the study site, the isotopic results indicate the occurence of two types of water; firstly the recharge is from the highlands where more negative 18 0 values and low tritium were observed and the second type is of local recharge where high tritium and less negative 18 0 values were observed. On the other hand, in the northern part of the basin the interpretation of stable isotopic results is quite difficult to be made at this stage. There was no correlation at all between tritium and 18 0 whatsoever. Results of the tritium assay show that some of the groundwater samples are pre-nuclear in age as indicated by low tritium content. Consequently, a Carbon-14 investigation was carried out from a few selected sites and their ages were found to be in the range of about 3000 to 5000 years. (author)

  11. Using Beads and Divided Containers to Study Kinetic and Equilibrium Isotope Effects in the Laboratory and in the Classroom

    Science.gov (United States)

    Campbell, Dean J.; Brewer, Emily R.; Martinez, Keri A.; Fitzjarrald, Tamara J.

    2017-01-01

    The purpose of this laboratory experiment is to study fundamental concepts of kinetics and equilibria and the isotope effects associated with both of these concepts. The concepts of isotopes in introductory and general chemistry courses are typically used within the contexts of atomic weights and radioactivity. Kinetic and equilibrium isotope…

  12. An environmental isotope study of a major dewatering operation at Sishen mine, northern Cape Province

    International Nuclear Information System (INIS)

    Verhagen, B.Th.; Smith, P.E.; Oosthuizen, J.H.

    1979-01-01

    Geohydrological studies using environmental isotopes of the Sishen iron ore mine were started after major rainfalls in 1973/74 produced flooding of the open cast workings. The mine is underlain by dolomite which has been extensively karstified and geohydrologically compartmentalized by several dykes. Major dewatering takes place in a pit called Hill 2 by pumping an array of large-diameter boreholes at a combined rate of 2000m 3 h -1 . The probable recharge areas (dolomites, superficial Kalahari Beds) were isotopically surveyed to assess their relative importance to the dewatering problem. Several major pumping outlets at the mine were regularly sampled for isotopic and chemical analysis and from the data a preliminary mixing model is proposed. The data also show that, with the total pumped volume up to March 1978, no very recent (i.e. post-bomb) water has reached the dewatering points. On this basis a minimum storage of 0.75x10 8 m 3 is derived compared with a classical calculation of 10 8 m 3 for the compartment. Isotopic composition and response differ for waters on either side of a dyke crossing the mining area, corroborating classical evidence suggesting that the dyke acts as an aquiclude. (author)

  13. Applications of compound-specific carbon isotope ratios in organic contaminant studies

    International Nuclear Information System (INIS)

    Aravena, R.; Hunkeler, D.; Bloom, Y.; Frape, S.K.; Butler, B.; Edwards, E.; Cox, E.

    1999-01-01

    In this paper results are presented on the application of compound-specific isotope ratios measurements to assess biodegradation of chlorinated solvents, in particularly on microbial dechlorination of tetrachloroethene (PCE) and trichloroethene (TCE). Analytical aspects and isotope data from laboratory and field studies are discussed. The analytical tests showed that both headspace and SPME techniques provide accurate δ 13 C values with a similar precision for a wide range of chlorinated solvents. However, the SPME method is generally more sensitive. The microcosm experiments show that a significant isotopic fractionation occurs during dechlorination of PCE and TCE to ethene. The largest fractionation factors are observed in the steps DCE-VC and VC-Ethene. In general, the δ 13 C of each dechlorination product was always more negative than the δ 13 C of the corresponding precursor. In addition, the δ 13 C values of each compound increased with time. A similar pattern was observed for dechlorination of PCE at a field site. These results show that compound-specific carbon isotope ratios technology is a very sensitive tool for evaluation of natural attenuation of chlorinated solvents in groundwater. (author)

  14. The use Pb- and Sr- isotopes for the study of Pacific Islander population

    International Nuclear Information System (INIS)

    Budd, P.; Gulson, B.L.; Montgomery, J.; Rainbird, P.; Thomas, R.G.; Young, S.

    1997-01-01

    Lead isotope measurements of dental enamel are regularly used as a means of determining information as to the source of the lead burden in modern human populations (Gulson and Wilson 1994). Lead ions have a considerable propensity to replace calcium ions in skeletal hard tissue; principally composed of hydroxy-apatite. The lead isotopic composition of teeth in adult humans has been shown to relate directly to the subject's exposure to the element at the time of eruption of their adult teeth and is unaffected by changes in the lead burden of an individual in latter life. In children, the analogous lead burden relates to the lead exposure of the mother during pregnancy and in the neo-natal period. Moreover due to its high crystallinity and density dental enamel does not undergo post-mortem recrystallization. This fact raised the exciting possibility that isotopic measurements of hard tissue could be used as a means of determining whether and individual is a migrant to a particular region. Despite a number of complications, briefly described, this paper presents the results of the ongoing study which uses measurements of Sr and Pb isotopes within dental enamel to determine the origin of Pacific Islander populations

  15. Interim report on modeling studies of two-photon isotope separation

    International Nuclear Information System (INIS)

    Hwang, W.C.; Badcock, C.C.; Kamada, R.F.

    1975-01-01

    The two-photon or two-step dissociation method of laser induced isotope enrichment is being modeled for the HBrNO photochemical system. In the model, H 79 Br is selectively excited by resonance IR laser radiation and then dissociated by uv radiation. Selectively dissociated Br atoms are scavenged to form isotopically enriched BrNO and Br 2 . This model includes all kinetic and absorption processes found to be significant and the time-varying concentrations of any species involved in a significant process. Among these processes are vibrational energy transfer reactions (including isotopic exchange) involving HBr v = 0 - 3, rotational and translational (velocity) relaxation processes, dissociation of HBr in the v = 0 - 3 levels, and secondary chemical reactions of the dissociation products. The absorption and kinetic processes that are most important to 79 Br enrichment have been identified and the study of the effects on enrichment upon variation of external parameters (such as reactant pressure, ir or uv source intensity, and temperature) is in progress. Some preliminary results are: (1) intensity of the ir source is usually more important than the uv intensity; (2) chemical reactions are the dominant kinetic processes at lower pressures while energy transfer reactions dominate at higher pressures; (3) kinetic processes usually have greater effect on the absolute amount of enriched products; (4) isotopic abundance of 79 Br in the products can range from 0.55 to 0.80 for the conditions used in the model

  16. An environmental isotope study of a major dewatering operation at Sishen mine, northern Cape Province

    International Nuclear Information System (INIS)

    Verhagen, B.T.; Smith, P.E.; Dziembowski, Z.; Oosthuizen, J.H.

    1978-01-01

    Geohydrological studies using environmental isotopes of the Sishen iron ore mine were started after major rainfalls in 1973/74 produced flooding of the open cast workings. The mine is underlain by dolomite which has been extensively karstified and geohydrologically compartmentalized by several dykes. Major dewatering takes place in a pit called Hill 2 by pumping an array of large diameter boreholes at a combined rate of 2000 m 3 h -1 . The probable recharge areas (dolomites, superficial Kalahari Beds) were isotopically surveyed to assess their relative importance to the dewatering problem. Several major pumping outlets at the mine were regularly sampled for isotopic and chemical analysis and from the data a preliminary mixing model is proposed. The data also show that with the total pumped volume up to March 1978, no very recent (i.e. post bomb) water has reached the dewatering points. On this basis a minimum storage of 0.75 x 10 8 m 3 is derived compared to a classical calculation of 10 8 m 3 for the compartment. Isotopic composition and response differ for waters on either side of a dyke crossing the mining area, corroborating classical evidence suggesting that the dyke acts as an aquiclude. (orig.) [de

  17. Hydrogeochemical and Isotopic Characteristics of Tufa Precipitating Wates: A Case Study of the River Krka (Slovenia)

    Energy Technology Data Exchange (ETDEWEB)

    Zavadlav, S.; Lojen, S. [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia)

    2013-07-15

    The geochemical and stable isotope composition of tufa precipitating water in the River Krka in the Slovenian karst area were studied. Surface water chemistry in the River Krka is controlled by groundwater interactions with carbonate rocks, soil CO{sub 2} and meteoric water in the aquifer. Major element chemistry of water is controlled by dissolution of dolomite and calcite. The aquifer is the main source of cations, since concentrations of Mg{sup 2+}, Sr{sup 2+} and Ba{sup 2+} in water are highest at the spring. Ca{sup 2+} concentrations are slightly increasing due to the additional mixing of surface and groundwater downstream. Oxygen isotope composition of water indicates homogenization of meteoric water in the aquifer, while {delta}{sup 13}C values of dissolved inorganic carbon in water are affected by biological activity in the soil. {delta}{sup 18}O and {delta}{sup 13}C of bulk tufa show that deposition of tufa precipitates in the River Krka is kinetically controlled resulting in enrichment with heavier isotopes. Calculated equilibrium temperature of tufa precipitation based on the oxygen isotope composition of water and tufa fit with measured water temperature when average {delta}{sup 18}O values of water and tufa are considered. (author)

  18. Isotopic variation in spring water and rain water of Sikkim: a case study

    International Nuclear Information System (INIS)

    Diksha; Sinha, U.K.; Ansari, Md. Arzoo; Mendhekar, G.N.; Dash, Ashutosh; Dhakal, Deepak

    2015-01-01

    Environmental stable isotopic signatures of surface water, rainwater and groundwater provide valuable information about interconnection between them. Stable isotopes of H (δ 2 H) and O (δ 18 O) have been widely employed by many researchers to understand rainwater, surface water and groundwater inter-connections. The Global Meteoric Water Line (GMWL, δD= 8 x δ 18 O+10) the locus of precipitation water over whole of the globe, established by Craig, used to tell about the environment of water. For the objective spring water (namely Dhalay Khola, Lower Changey and Bhulkey) were collected from the study area (Sikkim) during May 2013, March 2013 and August 2014. Rainwater sample were also collected with increasing altitude. These samples were analyzed for environmental isotopes (δ 2 H, δ 18 O) by a isotope ratio mass spectrometer (IsoPrime-100) using pyrolysis mode of elemental analyzer for deuterium and gas equilibration method for 18 O. The precision (2 sigma) of (δ 2 H and δ 18 O are ±0.15 and ± 0.1‰ respectively

  19. Isotope-aided studies of the bioavailability of iron from Myanmar diets

    International Nuclear Information System (INIS)

    Khin Maung Naing; Myo Khin

    1992-01-01

    Iron deficiency is an important nutritional problem in Myanmar. The preliminary studies in this paper are to be used as a feasibility study for an iron fortification programme in Myanmar. This programme is now in the planning stages. This paper contains summaries of information gathered from a dietary survey, isotope-aided studies of the bioavailability of iron from the daily diet, and a work plan for fortifying table salt with iron. 6 refs, 6 tabs

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

    International Nuclear Information System (INIS)

    Zielinski, M.; Czarnota, G.; Papiernik-Zielinska, H.

    1992-01-01

    The 13 C kinetic isotope fractionation in the decarbonylation of lactic acid of natural isotopic composition by sulfuric acid has been studied in the temperature range of 20-80 deg C. The 13 C (1) isotope separation in the decarbonylation of lactic acid by concentrated sulfuric acid depends strongly on the temperature above 40 deg C. Below this temperature the 13 C isotope effect in the decarbonylation of lactic acid by concentrated sulfuric acid is normal similarly as has been found in the decarbonylation of lactic [1- 14 C] acid. The experimental values of k (12C) /k (13C) ratios of isotopic rate constants for 12 C and 13 C are close to, but slightly higher than theoretical 13 C-kinetic isotope effects calculated (neglecting tunneling) under the asumption that the C (1) -OH bond is broken in the rate-controlling step of the dehydration reaction. Dilution of concentrated sulfuric acid with water up to 1.4 molar (H 2 O)/(H 2 SO 4 ) ratio caused the increase of the 13 C isotope fractionation from 1.0273 found in concentrated sulfuric acid at 80.5 deg C to 1.0536±0.0008 (at 80.6 deg C). A discussion of the abnormally high temperature dependence of 14 C and 13 C isotope fractionation in this reaction and the discussion of the problem of relative 14 C/ 13 C kinetic isotope effects is given. (author) 18 refs.; 2 tabs

  1. Isotopic study of water exchange between atmosphere and biosphere at different sites in Pakistan

    International Nuclear Information System (INIS)

    Fazil, M.; Ali, M.; Ahmad, M.; Latif, Z.; Butt, S.; Choudhry, M.A.; Qureshiu, R.M.

    2009-11-01

    Study of Isotopic behavior of water exchange between atmosphere and biosphere was initiated to understand the ties between these two spheres. This report presents the isotopic data of delta/sup 18/O and delta /sup 2/H in the water contents of leaves and stems in different plant species along with soil moisture. Non woody plants of wheat and grass along with soil from the surface and from the depth of 7 cm were collected during January 2005 to April 2005. Woody plants of many species were sampled from two sites near Islamabad and Lahore. Air moisture was also collected in the field. Moisture contents from these samples were extracted using the vacuum distillation method and analyzed for /sup 18/O and /sup 2/H Data depicts that the /sup 18/O and /sup 2/H of moisture in the leaves of non- woody and woody plants are much more enriched than their respective stems. This behavior is due to the evaporative enrichment trend originating from the soil moisture in the active root zone and also from the surface of the leaf. Degree of enrichment depends on the size of leaves, temperature, wind speed, stomatal resistance, soil chemistry and humidity. Significant evaporation effects in the moisture of grass stems are due to photosynthesis. Reflection of typical isotopic values of individual rain events is also observed in soil, plant water and atmospheric moisture, which can be used for studying water-use efficiency. Leaves of woody plants have relatively depleted/sup 18/O values during wet (monsoon) period mainly due to retardation of fractionation resulting from higher humidity. The stem samples do not show any significant variation in delta/sup 18/O indicating no evaporation from stems of big trees. Degree of enrichment of leave samples of woody plants also indicates the species- specific effects in oxygen and hydrogen isotopes during transpiration. Pine and Eucalyptus leaves show more variation in the isotopic contents as compared to other species. (author)

  2. Geochemical and isotopic study of soils and waters from an Italian contaminated site: Agro Aversano (Campania)

    Science.gov (United States)

    Bove, M.A.; Ayuso, R.A.; de Vivo, B.; Lima, A.; Albanese, S.

    2011-01-01

    Lead isotope applications have been widely used in recent years in environmental studies conducted on different kinds of sampled media. In the present paper, Pb isotope ratios have been used to determine the sources of metal pollution in soils and waters in the Agro Aversano area. During three different sampling phases, a total of 113 surface soils (5-20. cm), 20 samples from 2 soil profiles (0-1. m), 11 stream waters and 4 groundwaters were collected. Major element concentrations in sampled media have been analyzed by the ICP-MS technique. Surface soils (20 samples), all soil profiles and all waters have been also analyzed for Pb isotope compositions by thermal ionization (TIMS). The geochemical data were assessed using statistic methods and cartographically elaborated in order to have a clear picture of the level of disturbance of the area. Pb isotopic data were studied to discriminate between anthropogenic and geologic sources. Our results show that As (5.6-25.6. mg/kg), Cu (9-677. mg/kg), Pb (22-193. mg/kg), Tl (0.53-3.62. mg/kg), V (26-142. mg/kg) and Zn (34-215. mg//kg) contents in analyzed soils, exceed the intervention limits fixed by the Italian Environmental Law for residential areas in some of the sampled sites, while intervention limit for industrial areas is exceeded only for Cu concentrations. Lead isotopic data, show that there is a high similarity between the ratios measured in the leached soil samples and those deriving from anthropic activities. This similarity with anthropogenic Pb is also evident in the ratios measured in both groundwater and stream water samples. ?? 2010 Elsevier B.V.

  3. Water uptake in woody riparian phreatophytes of the southwestern United States: a stable isotope study

    International Nuclear Information System (INIS)

    Busch, D.E.; Ingraham, N.L.; Smith, S.D.

    1992-01-01

    Alluvial forest associations are often dominated by woody phreatophytes, plants that are tightly linked to aquifers for water uptake. Anthropogenic hydrological alterations (e.g., water impoundment or diversion) are of clear importance to riparian ecosystem function. Because decreased frequency of flooding and depression of water tables may, in effect, sever riparian plants from their natural water sources, research was undertaken to determine water uptake patterns for the dominant native and introduced woody taxa of riparian plant communities of the southwestern United States. At floodplain study sites along the Bill Williams and lower Colorado Rivers (Arizona, USA), naturally occurring D and 18 O were used to distinguish among potential water sources. Isotopic ratios from potential uptake locations were compared to water extracted from the dominant woody taxa of the study area (Populus fremontii, Salix gooddingii, and Tamarix ramosissima) to elucidate patterns of water absorption. Isotopic composition of water obtained from sapwood cores did not differ significantly from heartwood or branch water, suggesting that heartwood water exchange, stem capacitance, and phloem sap mixing may be inconsequential in actively transpiring Salix and Populus. There was evidence for close hydrologic linkage of river, ground, and soil water during the early part of the growing season. Surface soils exhibited D enrichment due to cumulative exposure to evaporation as the growing season progressed. Isotopic ratios of water extracted from Populus and Salix did not exhibit isotopic enrichment and were not significantly different from groundwater or saturated soil water sources, indicating a phreatophytic uptake pattern. Associations of isotopic ratios with water relations parameters indicated high levels of canopy evaporation and possible use of moisture from unsaturated alluvial soils in addition to groundwater in Tamarix. (author)

  4. Application of isotopic techniques for study of ground water from karstic areas. 1. Origin of waters

    International Nuclear Information System (INIS)

    Feurdean, Victor; Feurdean, Lucia

    2000-01-01

    Environmental stable isotope method was used for study of ground water from karst of NE Dobrogea. Study area is in the vicinity of Danube Delta (declared in 1990 by UNESCO the Reserve of Biosphere) and presents scientific and ecological interest. Measurements of deuterium content of ground water show that waters are meteoric in origin, but at the same time the results showed that the water from two sampling points could not originate from local ground water and have their recharge area at high altitude and a considerable distance. According to the δD values the following categories of waters were established: - waters depleted in deuterium (δD 0 / 00 ) relative to δD values of surface and ground water in the geographic area from which they were collected. They represent most probably the intrusion of isotopically light water from high altitude sites (higher than 1000 m) through network of highly permeable karst channels. The discharge of this component of aquifer occurs both by conduct flow and by diffuse flow; - Waters tributaries to the Danube River (δD > -75 0 / 00 ) that have a small time variability of δD values; - Local infiltration waters, situated in the West side of the investigated area towards the continental platform of the Dobrogea (δD > -70 0 / 00 ). They present high time variability of δD values, due to distinct seasonal effects; - Waters originated in mixing processes between the waters with different isotopic content. The endmember one is heavier isotopic water that belongs to local recharged waters (local infiltration waters and waters tributary to Danube river) while the other endmember is the isotopically light water. (authors)

  5. Groundwater Resources Isotope Study of Eastern and Southeastern Areas of Jordan

    International Nuclear Information System (INIS)

    Al-Momani, M. R.

    2004-01-01

    Since Jordan depends on the groundwater resources especially for municipal use so, water resources studies and development takes priority on the national level. For this reason the environmental isotope technique and application contributed and supported the hydrological studies as a research tool confirmed some scientific facts including natural and environmental changes of water resources. The isotope analyses has been implemented for upper and deep aquifer systems in the eastern and southeastern areas of Jordan for Hamad, Sirhan, Azraq and Jafr basins. The analyses included the stable isotopes for 18 O, Deuterium ( 2 H) and 13 C also the radioactive isotopes for Tritium ( 3 H ) and 14 C in nineties of the last century until 2002 and this indicates the following: * The origin and mechanism of the nonrenewable groundwater recharge in the deep aquifer systems of (B2/A7) Campanian and Turonian age for Hamad and Azraq basins has been defined. This refers that the groundwater recharge existed within humid, cold and wet climatologic conditions which is completely different from the present climate where the groundwater age exceeds thirty thousand years. * Also this indicates that the stable isotopic composition of the upper aquifers in Hamad and Sirhan basins in Shallala and Rijam aquifers (B5/B4) of Eocene and Paleocene age lie on the Global Meteoric Water Line (GMWL) where the deuterium excess (d) is 10 %. Actually this water is not tritiated and the 14 C content in the groundwater is close to zero which is a strong indication of humid and wet climate where the age of the groundwater range between 20000 and exceeds 300000 years. In comparison this situation with the same aquifer in Jafr basin located in the southeastern part of Jordan, there are differences in the deuterium excess (d), Tritium and 14 C content which depends on the climatologic conditions existed during the recharge period. Also the isotopic signaure for the middle groundwater system (B2/A7) and the

  6. Spectral density mapping at multiple magnetic fields suitable for C-13 NMR relaxation studies

    Czech Academy of Sciences Publication Activity Database

    Kaderavek, Pavel; Zapletal, V.; Fiala, R.; Srb, P.; Padrta, P.; Přecechtělová, J.; Šoltésová, M.; Kowalewski, J.; Widmalm, G.; Chmelík, Josef; Sklenář, V.; Žídek, L.

    2016-01-01

    Roč. 266, MAY2016 (2016), s. 23-40 ISSN 1064-1858 Institutional support: RVO:68081707 ; RVO:61388971 Keywords : molecular-orbital methods * protein backbone dynamics Subject RIV: BO - Biophysics; EE - Microbiology, Virology (MBU-M)

  7. DFT study of zigzag (n, 0) single-walled carbon nanotubes: C-13 NMR chemical shifts

    Czech Academy of Sciences Publication Activity Database

    Kupka, T.; Stachów, M.; Stobinski, L.; Kaminský, Jakub

    2016-01-01

    Roč. 67, Jun (2016), s. 14-19 ISSN 1093-3263 R&D Projects: GA ČR(CZ) GA14-03564S Institutional support: RVO:61388963 Keywords : zigzag SWCNT * cyclacenes * theoretical modeling * DFT * NMR Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.754, year: 2016

  8. Hydrodynamic influence on reservoir sustainability in semi-arid climate: A physicochemical and environmental isotopic study.

    Science.gov (United States)

    Ammar, Rawaa; Kazpard, Véronique; El Samrani, Antoine G; Amacha, Nabil; Saad, Zeinab; Chou, Lei

    2017-07-15

    Water scarcity and increasing water demand require the development of water management plans such as establishing artificial lakes and dams. Plans to meet water needs are faced by uprising challenges to improve water quality and to ensure the sustainability of hydro-projects. Environmental isotopes coupled to water physicochemical characteristics were investigated over a biennial cycle to assess both geomorphological and environmental impacts on the water quality of a reservoir situated in an intensively used agricultural watershed under a Mediterranean semi-arid climate. The particularity of the semi-arid climate and the diverse topography generate a continental and orographic rain effect on the isotopic composition of precipitation and the water recharged sources. The studied reservoir responds quickly to land-use activities and climatic changes as reflected by temporal and spatial variations of water chemistry and isotopic composition. Increasing changes in precipitation rate and dry periods significantly modified the water isotopic composition in the reservoir. During the first year, hydrogen (δD) and oxygen (δ 18 O) isotopes are depleted by 6 and 2‰ between dry and wet season, respectively. While a shift of -2‰ for δD and -1‰ for δ 18 O was detected during the second annual cycle. Environmental isotopic compositions demonstrate for the first time the occurrence of groundwater inflow to the central (Cz) and dam (Dz) zones of the Qaraaoun reservoir. The Cz and Dz can be considered as open water bodies subjected to dilution by groundwater inflow, which induces vertical mixing and reverse isotopic stratification of the water column. In the contrary, the river mouth zone acts as a closed system without groundwater intrusion, where heavy water accumulates and may act as a sink for contaminants during dry season. Groundwater influx acts as a dilution factor that renews the hypolimnion, and minimizes the perturbations induced by both internal

  9. Isotopic discrimination of stable isotopes of nitrogen (delta N-15) and carbon (delta C-13) in a host-specific holocephalan tapeworm

    Czech Academy of Sciences Publication Activity Database

    Navarro, J.; Albo-Puigserver, M.; Coll, M.; Saez, R.; Forero, M. G.; Kuchta, Roman

    2014-01-01

    Roč. 88, č. 3 (2014), s. 371-375 ISSN 0022-149X Institutional support: RVO:60077344 Keywords : food webs * fractionation * Gyrocotylidea * parasites * ecology * cercomeromorpha * Platyhelminthes * cercomeria * community * patterns Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.421, year: 2014

  10. Input of environmental isotopes in the study of the recharge and the flow dynamic of aquifers

    International Nuclear Information System (INIS)

    Aranyossy, J.F.; Njitchoua, R.; Zuppi, G.M.

    1998-01-01

    Several examples of hydrogeological studies have been selected in order to illustrate the input of environmental isotopic techniques in the general knowledge of aquifer systems: evaluation of the present aquifer recharge (Mali, Senegal, Italy, North-Cameroon, North-Sahara, Niger); evidence of the recharge variation with time (Niger, Italy, Vietnam); evaluation of the aquifer characteristics and hydraulic conditions (Chad, Niger). Most of these studies were carried out in collaboration with Professor Jean-Charles Fontes. (author)

  11. Use of stable isotopes in developing countries: safe markers for nutrition regime study

    International Nuclear Information System (INIS)

    Klein, P.D.; Klein, E.R.

    1987-01-01

    Possible use of stable radioisotopes in studies on nutrition and medicine problems that may be used in investigations of babies, children, pregnant women is shown. Attention is paid to behaviour of limited number of elements: hydrogen, carbon, nitrogen, oxygen. The IAEA plans implementation of a new coordinated research program on use of stable isotopes for studying nutrition problems and related diseases. The program emphasis will be placed on protein metabolism measurements and estimation of energy consumption in control population groups in developing countries

  12. Studies of unbound states in isotopes at the N = 8 shell closure

    CERN Multimedia

    We propose to study low-lying resonances in the two unbound isotopes $^{13}$Be and $^{10}$Li as well as low-lying resonances in $^{12}$Be. This will be done using an $^{11}$Be beam impinging on a tritium target leading to one- or two-particle transfer reactions. The decay scheme of the resonances will be studied using the MINIBALL and differential cross sections will be determined using T-REX.

  13. Theoretical study of band structure of odd-mass {sup 115,117}I isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dhanvir, E-mail: singh1472phy@gmail.com; Kumar, Amit, E-mail: akbcw2@gmail.com; Sharma, Chetan, E-mail: chetan24101985@gmail.com [Research Scholar, Department of Physics and Electronics, University of Jammu, Jammu-180006 (India); Singh, Suram, E-mail: suramsingh@gmail.com [Assistant Professor, Department of Physics, Govt. Degree College, Kathua-184101 (India); Bharti, Arun, E-mail: arunbharti-2003@yahoo.co.in [Professor, Department of Physics and Electronics, University of Jammu, Jammu-180006 (India)

    2016-05-06

    By using the microscopic approach of Projected Shell Model (PSM), negative-parity band structures of odd mass neutron-rich {sup 115,117}I nuclei have been studied with the deformed single-particle states generated by the standard Nilsson potential. For these isotopes, the band structures have been analyzed in terms of quasi-particles configurations. The phenomenon of back bending in moment of inertia is also studied in the present work.

  14. Effect of microtopography on isotopic composition of methane in porewater and efflux at a boreal peatland

    Energy Technology Data Exchange (ETDEWEB)

    Dorodnikov, M.; Wilmking, M. [Greifswald Univ. (Georgia). Inst. of Botany and Landscape Ecology; Marushchak, M.; Biasi, C. [Univ. of Eastern Finland, Kuopio (Finland). Dept. of Environmental Science, Bioteknia 2], E-mail: maxim.dorodnikov@uef.fi

    2013-09-01

    The application of stable isotopes is an approach to identify pathways of methanogenesis, methane (CH{sub 4}) oxidation and transport in peatlands. We measured the stable C isotopic characteristics ({delta}C-13) of CH{sub 4} in peat profiles below hummocks, lawns and hollows of a Finnish mire to study the patterns of CH{sub 4} turnover. Porewater CH{sub 4} concentrations ([CH{sub 4}]; at 0.5-2 m) increased with depth below all microforms. Emissions of CH{sub 4} from hummocks were the lowest, and increased with the increasing water-saturated zone, being {approx}10 times higher from hollows. Thus, the microtopography of the peatland did not affect the porewater [CH{sub 4}] in the water-saturated part of the peat profile, but the CH{sub 4} emissions were affected due to differences in the oxidative potential of the microforms. There was a decrease in {delta}C-13-CH{sub 4} with depth below all microforms indicating dominance of CO{sub 2}-reduction over acetate cleavage pathway of methanogenesis at deep peat layers. However, estimated potential portions of transported CH{sub 4} comprised 50%-70% of the {delta}C-13-CH{sub 4} enrichment on microforms at the 0.5-m depth, hereby masking the acetate cleavage pathway of methanogenesis. Stable C composition ({delta}C-13) of CH{sub 4} proved to be a suitable (but not sufficient) tool to differentiate between types of methanogenesis in continuously water-saturated layers below microforms of a peatland. Combined flux-based and multi-isotopic approaches are needed to better understand the CH{sub 4} turnover process. (orig.)

  15. Radiation and isotopic techniques in the study and control of piroplasms of cattle: a review

    International Nuclear Information System (INIS)

    Irvin, A.D.; Brocklesby, D.W.; Purnell, R.E.

    1979-01-01

    Radiation and isotopic techniques have been used in a number of ways to study Babesia and Theileria parasites (piroplasms), and in attempts to vaccinate animals against diseases induced by these agents. Work involving the piroplasm infections of cattle is reviewed in this paper. Some success has been achieved by using radiation to modify tick or bovine stages of parasites, for use as potential vaccines. Radiation has also been used to induce immuno-suppression in laboratory animals, in an effort to render them susceptible to bovine piroplasms, particularly Theileria. Isotope tracer techniques have been used for labelling parasites, and for studying metabolic pathways. Encouraging results, particularly with regard to vaccine development, indicate the importance of radiation techniques in the study and control of piroplasms of cattle. (Auth.)

  16. Study of band structure of some odd proton Eu isotopes

    International Nuclear Information System (INIS)

    Pandit, Rakesh K.; Rani Devi; Khosa, S.K.

    2016-01-01

    Much work has been done on the odd-Z, odd-A nuclei in the rare earth region because of occurrence of fascinating variety of structures of nuclei in this mass region. The Eu nuclei are in the transitional deformation region and it provides an opportunity to investigate theoretically the deformation changes with mass number and excitation energy besides to study the structure of their excited states. The 153 Eu nucleus has been well studied over the last two decades. The aim of the present work is to study in detail the band structure of some odd-Z nuclei

  17. Productions and interests of the radiopharmaceuticals labelled by 11C, 13N, 15O, and 18F

    International Nuclear Information System (INIS)

    Blanc-Borras, Louisette

    1985-01-01

    As medical diagnosis methods based on the use of short-life radioelements such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18 have been developed, these four radio-isotopes are notably adapted to external detection by tomography. Besides, due to their short period, their radioactive concentration per mass unity is very high. In the first part of this research thesis, the author presents the characteristics of these four radio-isotopes, describes the operation of cyclotrons and the principles, benefits, drawbacks, and types of positron emission tomography. The second part addresses the production of the radionuclides and precursors, the production of radiopharmaceutical products (haemoglobin, sugars, amino acids, fatty acids, steroid marking, and drug marking). The third part reports some studies illustrating the pharmaceutical interest of these radioelements [fr

  18. Studies of osteoporosis in Croatia using isotope related techniques

    International Nuclear Information System (INIS)

    Dekanic, D.; Blanusa, M.; Cvijetic, S.; Prester, L.; Uzelac, V.

    1996-01-01

    A short overview is presented of research activities concerning osteoporosis and trace element exposure monitoring carried out by the Institute for Medical Research and Occupational Health in Zagreb during the last forty years. The overview includes: cross-sectional and Prospective epidemiological studies in districts with habitually low and high calcium intake; clinical studies concerning peak bone mass and bone mineral density in Postmenopausal women; studies on trace element exposure monitoring. The collaborating institutions, agencies and relevant recent publications are quoted. A survey is given of relevant methods which were used in earlier studies as well as the techniques which will be used in the current IAEA project. A brief description of the work which will be undertaken (particularly during the first year) within the framework of the IAEA CRP is given. (author)

  19. Use of carbon isotopes in studies of environmental contamination

    International Nuclear Information System (INIS)

    Aravena, R.; Olave, S.; Ortiz, J.

    1986-01-01

    This report informs the preliminary results of a study on tree leaves undertaken in various areas of Santiago, aired at evaluating the pollution levels reached by combustion of fossil fuels, using carbon - 14 and carbon - 13 as natural tracers. (Author)

  20. Trophic relationships in a tropical stream food web assessed by stable isotope analysis

    OpenAIRE

    Coat, Sophie; Monti, Dominique; Bouchon, Claude; Lepoint, Gilles

    2009-01-01

    1. Stable isotope analysis, coupled with dietary data from the literature, was used to investigate trophic patterns of freshwater fauna in a tropical stream food web (Guadeloupe, French West Indies). 2. Primary producers (biofilm, algae and plant detritus of terrestrial origin) showed distinct delta C-13 signatures, which allowed for a powerful discrimination of carbon sources. Both autochthonous (C-13-enriched signatures) and allochthonous (C-13-depleted signatures) resources enter the food ...

  1. Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

    Science.gov (United States)

    Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

    2013-04-01

    The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity

  2. An integrated approach to isotopic study of crystalline rock for a high-level waste repository: Area phase

    International Nuclear Information System (INIS)

    Gilbert, L.A.

    1986-01-01

    An integrated approach to assessing isotopic systems in crystalline rock is planned for area phase studies. This approach combines radiogenic isotope systems with petrography in order to characterize potential crystalline repository media. The coeval use of selected isotope systems will minimize the limitations of each method and provide intensive parameters yielding data on alteration timing, secondary mineral formation, temperature history, and radionuclide species migration. Isotope systems will be selected in order to measure differences in sensitivity to thermal disturbances and mobility due to fluid interaction. Comparative evaluation of isotope pair behavior may be used in combination with mineral versus whole-rock dates to provide data on heating and mobilization of alkali elements, lanthanides, and gases, caused by future introduction of waste

  3. Studies of osteoporosis in Russia using isotope-related techniques

    International Nuclear Information System (INIS)

    Zaichick, V.

    1998-01-01

    The main aim of the present study was to estimate the age dependence of mineral density for the different body regions in healthy population of the Russian European area (Moscow and surroundings). Besides, bone mineral density (BMD) was to be analyzed by two ways: both in vivo and in vitro. In vivo studies were carried out using the method of DEXA (LUNAR DPX-L Densitometer) at the Central Institute of Traumatology and Orthopedics (Moscow) on volunteers randomly chosen. Autopsy material received from Forensic Department of Municipal Hospital (Obninsk) was used for in vitro NAA analysis. For August 31, 1996 bone mineral density was studied by DEXA on 94 healthy citizens of Moscow aged 15-55 (62 women and 32 men). Bone mineral density of femoral neck (right and left), spine (front view, L 2 -L 4 ) and total body was measured in each studied person. All the examined people were also put questions by a doctor to fill in the appropriate questionnaire (an adapted version of WHO osteoporosis project questionnaire, case control study, July 15, 1993)

  4. hydrological study of the basin of Tunja using isotopics technical

    International Nuclear Information System (INIS)

    Camacho R, Gloria; Hernandez Luis

    1992-01-01

    In the carried out study, it is analyzed the generalities in the first place on the city of Tunja, keeping in mind the aspects of Topography, Climate Population and the projection of this last one until the year 2020, and of equal it forms the demand of drinkable water for these same projections. Then it is the Superficial Hydrology of the area in study, keeping in mind the physiographic parameters of the basin, behavior pluviometrical graphic, flows and evapotranspiration, towards them to calculate this way the infiltration and power to end up determining the hydraulic balance of the area. In the concerning to Geology, this it was carried out on the base of the rising of stratigraphic columns made in having traveled by different roads and roads bordering to the study area; based on this columns it was carried out a geologic map with all the characteristics of the formations in the area

  5. Studies on cryogenic distillation columns for hydrogen isotope separation

    International Nuclear Information System (INIS)

    Kinoshita, Masahiro

    1984-08-01

    Cryogenic distillation is applicable to a number of situations. The feed condition, column cascade configuration, input and output specifications vary greatly from situation to situation. In the mainstream fuel circulation system for a fusion reactor, the feed composition may fluctuate greatly during the operation. The radiological standards for tritium lost to the environment are increasingly becoming stricter. Systematic studies are needed to achieve the goal of long-term operation meeting the strict requirements for products even under great fluctuation of the feed condition in all the situations. The present report gives a critical, brief review of the studies which have been made by the author. The subjects treated are development of computer simulation procedures, analysis on an H-T separation column with a feedback stream, dynamics and control, proposal of a new cascade, analysis on helium effects on column behavior, start-up analysis for a cascade, and preliminary experimental study on dependence of HETP on operational conditions. (author)

  6. Studies of osteoporosis in Russia using isotope-related techniques

    International Nuclear Information System (INIS)

    Zaichick, V.

    1996-01-01

    Here presented is the programme to study bone characteristics of healthy men and women aged 20-54 comprising the urban population of Moscow and nearby cities to define those of normal population. The study will also include patients with characteristics for early osteoporosis symptoms. The latter includes subjects who took part in the Chernobyl clean-up operation. DEXA (spine, femoral neck, whole body) and ultrasound (heel) will be used to examine those of the normal population group. To study osteoporosis patients the iliac crest biopsy samples will be taken for subsequent neutron activation analysis. Contents of major and trace elements in bone specimens (rib, iliac crest) and teeth (molar, premolar) will be estimated by neutron activation and X-ray fluorescent analysis in autopsy material of healthy accident victims depending on the age and sex. (author)

  7. Studies of colossal magnetoresistive oxides with radioactive isotopes

    CERN Document Server

    CERN. Geneva. ISOLDE and Neutron Time-of-Flight Experiments Committee; Amaral, V S; Araújo, J P; Butz, T; Correia, J G; Dubourdieu, C; Habermeier, H U; Lourenço, A A; Marques, J G; Da Silva, M F A; Senateur, J P; Soares, J C; Sousa, J B; Suryan, R; Tokura, Y; Tavares, P B; Tomioka, Y; Tröger, W; Vantomme, A; Vieira, J M; Wahl, U; Weiss, F P; INTC

    2000-01-01

    We propose to study Colossal Magnetoresistive (CMR) oxides with several nuclear techniques, which use radioactive elements at ISOLDE. Our aim is to provide local and element selective information on some of the doping mechanisms that rule electronic interactions and magnetoresistance, in a complementary way to the use of conventional characterisation techniques. Three main topics are proposed: \\\\ \\\\ a) Studies of local [charge and] structural modifications in antiferromagnetic LaMnO$_{3+ \\delta}$ and La$_{1-x}$R$_{x}$MnO$_{3}$ with R=Ca and Cd, doped ferromagnetic systems with competing interactions: - research on the lattice site and electronic characterisation of the doping element. \\\\ \\\\ b) Studies of self doped La$_{x}$R$_{1-x}$MnO$_{3+\\delta}$ systems, with oxygen and cation non-stoichiometry: -learning the role of defects in the optimisation of magnetoresistive properties. \\\\ \\\\ c) Probing the disorder and quenched random field effects in the vicinity of the charge or orbital Ordered/Ferromagnetic phase...

  8. Studies of Colossal Magnetoresistive Oxides with Radioactive Isotopes

    CERN Multimedia

    2002-01-01

    We propose to study Colossal Magnetoresistive (CMR) oxides with several nuclear techniques, which use radioactive elements at ISOLDE. Our aim is to provide local and element selective information on some of the doping mechanisms that rule electronic interactions and magneto- resistance, in a complementary way to the use of conventional characterisation techniques. Three main topics are proposed: \\\\ \\\\ a) Studies of local [charge and] structural modifications in antiferromagnetic LaMnO$_{3+\\delta}$ and La$_{1-x}$R$_{x}$MnO$_{3}$ with R=Ca and Cd, doped ferromagnetic systems with competing interactions: - research on the lattice site and electronic characterisation of the doping element. \\\\ \\\\ b) Studies of self doped La$_{x}$R$_{1-x}$MnO$_{3+\\delta}$ systems, with oxygen and cation non- stoichiometry: - learning the role of defects in the optimisation of magnetoresestive properties. \\\\ \\\\ c) Probing the disorder and quenched random field effects in the vicinity of the charge or orbital Ordered/Ferromagnetic p...

  9. Studies of osteoporosis in Singapore using isotopic related technique

    International Nuclear Information System (INIS)

    Bose, Kamal

    2002-01-01

    Osteoporosis is becoming increasingly common in Asia as the population ages. It has been projected that 50% of all hip fractures in the world will occur in Asia by the next century. Singapore is not exempted from this problem of global aging as figures show that there is a rising incidence of hip fractures in the country. So far, studies on bone density in Singapore have been reported only for the Chinese population. Apart from the bone density, it has been reported that femoral neck geometry, like the hip axis length, contributed independently to the risk of hip fracture. The hip axis length is defined as the length from the lateral bone edge below the greater trochanter through the femoral neck to the medial bone edge of the inner pelvic brim. A longer hip axis length was associated with an increased risk of hip fractures. Several studies have also shown some racial differences in hip axis length. The Study of Osteoporotic Fractures Research Group found that the mean hip axis length of Asian and black women were significantly shorter than that of white women. In a recent study, women of African origin were found to have smaller bone widths and a shorter hip axis length than Caucasians. The authors estimated that this racial difference could contribute to almost 25% decrease risk of hip fracture among blacks. Likewise, a shorter hip axis length in Japanese women compared to American women may explain the lower incidence of hip fractures among the Japanese population despite lower BMD values. The main objectives of this study were: a) To determine the age of peak bone density in each study group b) To quantify differences in bone density as functions of age and sex c) To determine any differences in bone density and hip axis length among Chinese, Malay and Indian population. This report presents the results of BMD measurement and the data analysis performed

  10. Comparative international studies of osteoporosis using isotope techniques

    International Nuclear Information System (INIS)

    Krishnan, S.

    2002-01-01

    Over three hundred volunteers were recruited through newspaper advertisements and other means to measure the BMD of the lumbar spine and femoral neck of normal healthy Canadians from the Toronto area. Trained scientists or medical personnel with respect to their medical history, lifestyle and habits carefully interviewed all these people. Persons with histories that will affect bone mineral status were excluded from the study. The resulting study population consisted of 200 persons. The data was used to determine the age or the range of ages at which peak BMD is attained in this normal population. The measurements were made using a DEX4 instrument made by Hologic Inc., Model 1000W. (author)

  11. Skeletal metastases in pancreatic carcinoma: study by isotopic bone scanning

    Energy Technology Data Exchange (ETDEWEB)

    Hatfield, D R; Deland, F H; Maruyama, Y

    1976-01-01

    A review of the literature of 2,155 reported patients with primary carcinoma of the pancreas, revealed 110 cases or 5 percent to have skeletal metastasis by radiographic or autopsy study. A study conducted over a 2 year period disclosed that 1 case of skeletal metastasis was detected by bone scanning in 16 patients with pancreatic carcinoma. This indicates a minimum skeletal metastasis rate of 6 percent. We feel these percentages are low and can be further defined by the more routine employment of the bone scan to evaluate patients with carcinoma of the pancreas. The true figure may be much higher, perhaps as high as 20 percent.

  12. Isotopic study of liver function after narcosis in small animals

    International Nuclear Information System (INIS)

    Le Qui Cuong; Kiss, Bela; Jakab, Tivadar; Szilvasi, Istvan; Spett, Borbala

    1984-01-01

    Dinamic functional study of the liver was performed by sup(99m)Tc-TECHIDA in narcotized (Halothane) mice and rabbits. Hepatic uptake of the radiopharmaceutical decreased in narcotized group significantly. Excretion also decreased but statistically insignificantly. These alterations in the liver function could be attributed to the hypotensive effect of Halothane. (author)

  13. Studies on osteoporosis in Chile using isotope-related techniques

    International Nuclear Information System (INIS)

    Lobo, G.

    1998-01-01

    The relationship found between BMD of the lumbar spine with the anthropomorphic parameters (age, sex, body size and bone area) in the normal Chilean population studied, was different from the relationship found between BMD of both hips with the same parameters. To determine peak bone mass it is necessary to increase the number of individuals studied. This is specially true for BMD of the lumbar spine. It seems important for the correct interpretation of BMD studies to determine local values for normals, specially for the analysis of BMD in the lumbar spine, which is related to body and bone size. It is necessary to normalize the data base for anthropomorphic parameters specially in epidemiological studies. Knowledge of these parameters for the normal data base used in the different densitometers is highly desirable. There are some differences between this data base and that provided by Hologic, specially for spine in both sexes. This difference could be explained by size related factors. There is a correlation between osteocalcin levels and BMD in lumbar spine and both femoral necks only in women

  14. Studies of osteoporosis in Singapore using isotope related technique

    International Nuclear Information System (INIS)

    Bose, K.; Goh, J.; Lee Soon Tai; Shamal Das De

    1996-01-01

    The main objectives of this study will be to determine the bone density in selected populations for the purposes of i)determining the age of peak bone mass in each study group and ii)quantifying the differences in bone density as functions of the age and sex of persons in the study group as well as quantifying the differences between study groups in different countries. Normal healthy subjects of both sexes across the age range of 15-50 will be recruited for this programme. There will be at least 15 subjects in each 5 year age range (i.e. a total of 105 subjects of each sex). The subjects will be of urban residency. The project will take a maximum of five years. Volunteers will be recruited from the hospital personnel and their friends and relatives. The subjects will be healthy individuals with no history of fractures and they should not be on any medication which may affect the bone density. A questionnaire regarding their lifestyle factors such as exercise, coffee/tea/alcohol intake and medication be filled. The subjects will also have X-rays of the dorsolumbar spine taken to ascertain the absence of scoliosis or crush fractures. Bone mineral density will be measured by dual energy X-ray absorptiometry using a Norland XR-26 bone densitometer. The BMD in the L2-L4 region of the lumbar spine and right hip which includes the femoral neck, trochanter and Ward's triangle will be scanned. Body composition will also be determined by doing a whole body scan on the subjects. Autopsy samples of rib bones from healthy accident victims in the age range 20-50 years will be obtained and the biomechanical strength of these bones will be tested. Biopsy specimens of the iliac crest will also be obtained to study the differences in trace element composition between osteoporotic patients and controls. (author)

  15. Contribution to the structure study of mercury isotopes with the (p,d) reaction

    International Nuclear Information System (INIS)

    Grafeuille, S.

    1985-10-01

    The mercury isotopes were studied by means of the two pick-up reactions (p,d) and (p,t). Enriched targets of 204 Hg, 202 Hg, 201 Hg, 200 Hg, 199 Hg, 198 Hg and 196 Hg were bombarded by a 25 MeV proton beam from the Orsay MP tandem accelerator. Emitted particles were analyzed by a split-pole magnetic spectrometer. We present all the results (nearly 150 states) of the analysis of the (p,d) reactions. Our (p,d) and (p,t) study show new discontinuities around 200 Hg in systematics of mercury isotopes. Part of the results are compared to the U(5) limits of Interacting Bosons (and Fermions) Models. The light nuclei can be considered reasonably described but this could be somewhat fortuitous. (71 refs) [fr

  16. Computer study of isotope production for medical and industrial applications in high power accelerators

    Science.gov (United States)

    Mashnik, S. G.; Wilson, W. B.; Van Riper, K. A.

    2001-07-01

    Methods for radionuclide production calculation in a high power proton accelerator have been developed and applied to study production of 22 isotopes. These methods are readily applicable both to accelerator and reactor environments and to the production of other radioactive and stable isotopes. We have also developed methods for evaluating cross sections from a wide variety of sources into a single cross section set and have produced an evaluated library covering about a third of all natural elements that may be expanded to other reactions. A 684 page detailed report on this study, with 37 tables and 264 color figures, is available on the Web at http://t2.lanl.gov/publications/.

  17. Comparative international studies of osteoporosis using isotope techniques

    International Nuclear Information System (INIS)

    Krishnan, S.

    1998-01-01

    Over 200 volunteers were recruited through Newspaper advertisements and other means to measure the BMD of the Lumbar Spine, Femoral Neck and Whole Body of normal healthy Canadians from the Toronto Area. All these people were carefully interviewed by trained scientists or medical personnel with respect to their medical history, life style and habits. Persons with histories that will affect bone mineral status were excluded from the study. The resulting study population consisted of 137 persons. The data was used to examine, using statistical methods, the parameters which determine bone mineral status of normal persons. The DEXA and In-vivo Neutron Activation Analysis (IVNAA) data on the same persons were compared. Further, the data was used to determine the age at which peak BMD is attained in this normal population. The Measurements were made using a DEXA instrument made by Hologic Inc., Model 1000 W. (author)

  18. Studies on osteoporosis in Chile using isotope-related techniques

    International Nuclear Information System (INIS)

    Lobo, G.; Palma, T.; Cortes-Toro, E.

    1996-01-01

    Several studies on bone densitometry measurements in healthy individuals have been performed in Chile. However due to the fact that different techniques and no uniform protocols have been used to select patients, the results obtained are not suitable as reference values for a normal chilean population. Therefore, foreign reference values are used. This study will select healthy normal individuals, typical urban chilean residents, and measure bone density using the DEXA technique. The selection will be made according to a well defined protocol. Serum osteocalcin, a marker of bone remodeling, will be measured in all subjects as a means-a assessing bone metabolism. Bone trace element composition will be measured in selected subjects. Samples will be obtained by biopsy or through normal surgical procedures and will be analyzed by neutron activation analysis. (author)

  19. Studies on osteoporosis in Chile using isotope-related techniques

    International Nuclear Information System (INIS)

    Lobo, G.; Palma, T.; Cortes, E.

    2002-01-01

    According to the objectives stated in the last coordination meeting, bone mass density (BMD) measurement in men and women belonging to healthy Chilean population were continued. The selection of individuals was made in the manner described in previous reports using the same exclusion criteria and the modified WHO questionnaire. This report presents the results of BMD measurement performed from the beginning of this study until December 1999

  20. Studies on osteoporosis in Chile using isotope-related techniques

    International Nuclear Information System (INIS)

    Lobo, G.; Palma, T.; Cortes, E.

    2000-01-01

    According to the objectives stated in the last coordination meeting, Bone mass density (BMD) measurements in men and women belonging to a healthy Chilean population, were continued. The selection of individuals was made in the manner described in previous reports, using the same exclusion criteria and using the modified WHO questionnaire. We present in this report the results of BMD measurements performed from the beginning of this study until May 1998. A statistical analysis of the data is presented

  1. Studies of osteoporosis in Shanghai, China, using isotope related techniques

    International Nuclear Information System (INIS)

    Zhang Yuanxun; Zhang Yongpeng; Qin Junfa; Li Deyi; Ma Jixiao; Hua Qian

    1996-01-01

    Using Hologic QDR-2000 DEXA, the BMD determinations of subjects suffering from osteoporosis and normal persons are in progress in Shanghai, China. A primary correlation between the kidney disease and the osteoporosis has been obtained. The studies of multi elemental distribution in cancellous bone of femoral head are also performed by PIXE. According to IAEA Co-ordinated Research Programme (CRP), a further working arrangement has been planned. (author)

  2. Comparative international studies of osteoporosis using isotope techniques

    International Nuclear Information System (INIS)

    McCloskey, E.V.; Dey, A.; Bostock, J.

    2002-01-01

    In Europe, there are great geographic variations in rates of osteoporotic fracture. The MEDOS study, a case-control study of hip fracture in southern Europe, demonstrated rates that in some age groups varied geographically by more than an order of magnitude. Additionally the prevalences of vertebral deforinities vary over a 3-fold range in both sexes. The incidence of hip fracture has also been shown to vary between another populations with apparently lower rates in Hong Kong and South Africa in Europe and North America. The greatest projected increases in hip fracture incidence will occur in China and South East Asia. It seems likely that the spread of fracture risk can at least be accounted for partly by differences in bone density. Bone density in later life is dependent on the maximum bone mass ('peak' bone mass) attained in early adulthood and the subsequent rate of loss. The purpose of this study was to determine whether early adult BMD varied between populations and to explore environmental and nutritional contributions to any detennined differences. The data analysed to-date demonstrate a highly significant difference in young adult bone mass across the centers. These differences are only partly attributable to differences in height and weight. By and large, low femoral neck BMD is accompanied by low spinal BMD. Femoral neck BMD appears constant between the age of 25-45 years, but this will require confirmation by further statistical analysis. The impact of family history, environmental factors and nutrition will be explored in subsequent analyses

  3. Strontium isotopic study of sediment from the Ross Sea

    International Nuclear Information System (INIS)

    Kovach, J.; Faure, G.

    1977-01-01

    A preliminary report summarizing the results of a study of the strontium-87/strontium-86 ratios and of the rubidium and strontium concentrations of the fine-grained (less than 150 microns) noncarbonate fractions of sediment samples from core E32-25 raised from a depth of 327 fathoms in the Ross Sea at 78 0 31.0'S 164 0 24.7'W was presented. The strontium-87/strontium-86 ratios of the samples analyzed range from 0.7119 to 0.7220. Rubidium and strontium concentrations range, respectively, from 126 to 164 parts per million and from 113 to 174 parts per million. The observed strontium-87/strontium-86 ratios and strontium concentrations in sediment samples from core E32-25 fit a hyperbolic curve. These ratios can be used to estimate the concentrations of volcanogenic detritus in the sediment samples. The results of this study provide additional baseline data for anticipated future studies of sediment cores to be recovered from beneath the Ross Ice Shelf by the Ross Ice Shelf Project. 1 figure

  4. Decay studies and mass measurements on isobarically pure neutron-rich Hg and Tl isotopes

    CERN Multimedia

    Schweikhard, L C; Savreux, R P; Hager, U D K; Beck, D; Blaum, K

    2007-01-01

    We propose to perform mass measurements followed by $\\beta$- and $\\gamma$-decay studies on isobarically pure beams of neutron-rich Hg and Tl isotopes, which are very poorly known due to a large contamination at ISOL-facilities with surface-ionised francium. The aim is to study the binding energies of mother Hg and Tl nuclides, as well as the energies, spins and parities of the excited and ground states in the daughter Tl and Pb isotopes. The proposed studies will address a new subsection of the nuclear chart, with Z 126, where only 9 nuclides have been observed so far. Our studies will provide valuable input for mass models and shell-model calculations: they will probe the proton hole-neutron interaction and will allow to refine the matrix elements for the two-body residual interaction. Furthermore, they also give prospects for discovering new isomeric states or even new isotopes, for which the half-lives are predicted in the minute- and second-range.\\\\ To reach the isobaric purity, the experiments will be p...

  5. Studies of osteoporosis in Croatia using isotope related techniques

    International Nuclear Information System (INIS)

    Dekanic, D.; Cvijetic, S.; Bolanca, S.; Blanusa, M.; Prester, L.; Korsic, M.

    1998-01-01

    Research activities concerning the IAEA Osteoporosis Study in Croatia, during the period November 1995 - September 1996, are presented, as well as a brief summary of the study, revealing the effect of combined therapy with antiresorptive and bone stimulating agents on bone mineral density in postmenopausal women with osteopenia and osteoporosis. Bone mineral density was measured by the method of dual energy X-ray absorptiometry (Lunar DPX) in the lumbar spine (L 2 -L 4 ) and at the left proximal femur (neck, Ward, trochanter) in a representative sample of 112 subjects of both sexes in the age range 15-50 years, from the city of Zagreb. Analysis of the scans and statistical evaluation of data are in progress. In a pilot study conducted in a sample of 67 college girls, ages 16-18, calcium intake, type and frequency of physical activity, alcohol consumption and smoking habit were roughly evaluated by use of a questionnaire. Height (cm), weight (kg) and calcium intake (mg/day) were (mean - + SD) 169.4- + 5.7, 57.8- + 6.1, 937- + 327, respectively. About 20 percent of girls drank less than 10 dL of wine or beer and less than 2 dL of spirits weekly, while 8% of them consumed 15-20 dL of wine or beer and 3-6 dL of spirits weekly. Fifteen percent smoked up to 20 cigarettes weekly and 5 percent 30-60 cigarettes weekly. Approximately 50 percent were regularly involved, in some kind of sporting activity, 2-3 times a week. Steps have been undertaken to organize evaluation of the present - day dietary habits of children from Istria, a part of Croatia, which was previously known as a low calcium region. All procedures necessary to start the work on a supplementary programme have been carried out. The plan for future work within the framework of the IAEA-CRP Osteoporosis Study is presented. The effect on bone mineral density of intermittent cyclical treatment with etidronate (group A) alone (400 mg orally for two weeks, followed by 500 mg of calcium daily for the next 10 weeks

  6. Isotopic tracer aided studies of fenvalerate residues in stored rice

    International Nuclear Information System (INIS)

    Varca, L.M.; Sanchez, T.E.; Magallona, E.D.

    1990-01-01

    Following application of 14 C-fenvalerate to milled rice and paddy rice at a concentration of 0.33 mg/kg, only insignificant losses were measured after 9 months. Distribution patterns in surface, methanol extractable and bound residues were studied. Paddy rice contained less extractable residues than milled rice, with the major part being found in the husk. Bound residues in both milled and paddy rice decreased also with length of storage; as much as 30% was found as bound residues after nine months. Cooking reduced the insecticide residues in milled rice by 33-40% and residues in paddy rice by 58%. (author). 8 refs, 1 fig., 4 tabs

  7. Studies of osteoporosis in Shanghai, China, using isotope related techniques

    International Nuclear Information System (INIS)

    Zhang Yongpeng

    2000-01-01

    This paper deals with the osteoporosis model of New Zealand rabbits in order to study the functions of inorganic elements for women patients with osteoporosis. The thirty cases of iliac crest are collected and determined using Neutron Activation Analysis (NAA) technique. The results show that the Fluorine concentrations in experimental group are higher than those in control group and the Magnesium concentrations are lower significantly (P<0.001), but the concentrations of K, Na, Ca, Ba, Mn, Sr are not remarkable difference. Combined with the serum biochemical markers of bone formation and resorption, the physiological functions of some metal elements in bone are also discussed. (author)

  8. Studies of osteoporosis in Croatia using isotope related techniques

    International Nuclear Information System (INIS)

    Cvijetic, Selma

    2002-01-01

    The study about bone stiffness in children and adolescents is finished. The relationship between habitual calcium intake, anthropometric measurements and bone stiffness was determined. In order to establish a national reference database, bone mineral density (BMD, g/cm2) of the lumbar spine (L2-L4) and of the left femoral neck of randomly chosen subjects, aged 20-49 years, was measured by dual x-ray absorptiometry (Lunar DPX). This report presents the results of BMD measurement and the data analysis performed

  9. Isotope techniques in catchment behaviour studies with particular emphasis on snowmelt runoff investigations

    International Nuclear Information System (INIS)

    Yurtsever, Y.

    1984-05-01

    The dynamics of runoff occurring mainly by snowmelt have been investigated by the aid of environmental isotopes. Regular samples collected from river water and snow cover throughout 1978 to 1981 at two selected catchment basins in eastern Turkey were analysed for their oxygen-18, deuterium and tritium contents. The tritium results together with detailed hydrological and hydro-meteorological data have enabled to study the time distribution of various component flow systems involved in the total runoff resulting from snowmelt

  10. Isotope hydrology study of Kalamos region (Attiki) and of the Assopos river basin

    International Nuclear Information System (INIS)

    Leontiadis, J.L.

    1980-10-01

    The isotopic composition of the water was used to determine the mechanism of recharge of the Assopos river basin and that of the Kalamos springs issuing brackish water near the coast. The results of the study permitted the catchment of the water before its salinization. A quantity of 73000 m 3 per day is now pumped and used as additional drinkable water for the major area of Athens covering about the 1/6 of the corresponding mean daily consumption. (T.A.)

  11. Memory Effects Study of Measuring Radioactive Xenon Isotopes With β-γ Coincidence Method

    International Nuclear Information System (INIS)

    Jia Huaimao; Wang Shilian; Wang Jun; Li Qi; Zhao Yungang; Fan Yuanqing; Zhang Xinjun

    2010-01-01

    The β-γ coincidence technique is a kind of the key important method to detect radioactive xenon isotopes for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). This paper describes noble gases memory effects of β-γ coincidence detector. Xenon memory effects were measured and its influence on detector's minimum detectable activity (MDA) was evaluated. The methods of reducing xenon memory effects were studied. In conclusion, aluminium coated plastic scintillator and YAP scintillator can remarkably decrease xenon memory effects. (authors)

  12. Application of isotopic and chemical methods to the study of hydrological problems in Brazilian northeastern areas

    International Nuclear Information System (INIS)

    Ponte, J.H.

    1979-01-01

    Hydrological studies are reported with samples of ground water from several region of northern - and northeastern Brazil: Marajo Island (State of Para), State of Piaui, Ceara and Rio Grande do Norte. A description is given of the utilization of chemical and isotopic methods, in particular measurements of tritium concentration and 14 C- counting techniques for the determination of the origin and residence time of water. (I.C.R.) [pt

  13. The MOON-1 detector construction and the study of backgrounds from radioactive isotopes

    International Nuclear Information System (INIS)

    Ogama, T; Nakamura, H; Ejiri, H; Fushimi, K; Ichihara, K; Matsuoka, K; Nomachi, M; Hazama, R; Umehara, S; Yoshida, S; Sakiuchi, T; Hai, V H; Sugaya, Y

    2006-01-01

    MOON is a multilayer system of plastic scintillators and 100 Mo films for 100 Mo 0νββ decays. A prototype detector MOON-1 was built with 6 layers of plastic scintillators and 142g of 100Mo films for background (BG), energy and position resolution studies of the MOON detector. No serious BG from natural radioactive isotopes (RI) for 0νββ detection was found

  14. Isotopic labelling studies for a gold-catalysed skeletal rearrangement of alkynyl aziridines

    Directory of Open Access Journals (Sweden)

    Neil Spencer

    2011-06-01

    Full Text Available Isotopic labelling studies were performed to probe a proposed 1,2-aryl shift in the gold-catalysed cycloisomerisation of alkynyl aziridines into 2,4-disubstituted pyrroles. Two isotopomers of the expected skeletal rearrangement product were identified using 13C-labelling and led to a revised mechanism featuring two distinct skeletal rearrangements. The mechanistic proposal has been rationalised against the reaction of a range of 13C- and deuterium-labelled substrates.

  15. Studies of osteoporosis in Singapore using isotope-related techniques

    International Nuclear Information System (INIS)

    Bose, K.

    1998-01-01

    The main objectives of this study was to determine the bone density for the purposes of i) determining the age of peak bone mass in each study group and ii) quantifying the differences in bone density as functions of age and sex. The results of estimating the age dependence of mineral density for the femoral neck, spine and total body of healthy women and men using DEXA are given. The age changes in concentrations of major minerals and electrolytes found for compact and trabecular bones of healthy male femoral neck with regard for the wet and dry tissue calculations are represented. Information about femoral neck water content depending on the age of healthy men is tabulated. The number of performed observations and analyses is evidently insufficient to make any final decision, however some preliminary conclusions can be drawn. In accordance with DEXA results, BMD maximum for the femoral neck, spine and total body of healthy women is found for 31-35 age period while that of healthy men is reached by 21-25 age period, i.e. 10 year earlier. Follow INAA results, the full-value mineralization for both compact and trabecular tissue of healthy male femoral neck takes place by 15-20 age period

  16. Isotopic reconstruction of ancient human migrations: A comprehensive Sr isotope reference database for France and the first case study at Tumulus de Sables, south-western France

    Science.gov (United States)

    Willmes, M.; Boel, C.; Grün, R.; Armstrong, R.; Chancerel, A.; Maureille, B.; Courtaud, P.

    2012-04-01

    Strontium isotope ratios (87Sr/86Sr) can be used for the reconstruction of human and animal migrations across geologically different terrains. Sr isotope ratios in rocks are a product of age and composition and thus vary between geologic units. From the eroding environment Sr is transported into the soils, plants and rivers of a region. Humans and animals incorporate Sr from their diet into their bones and teeth, where it substitutes for calcium. Tooth enamel contains Sr isotope signatures acquired during childhood and is most resistant to weathering and overprinting, while the dentine is often diagenetically altered towards the local Sr signature. For the reconstruction of human and animal migrations the tooth enamel 87Sr/86Sr ratio is compared to the Sr isotope signature in the vicinity of the burial site and the surrounding area. This study focuses on the establishment of a comprehensive reference map of bioavailable 87Sr/86Sr ratios for France. In a next step we will compare human and animal teeth from key archaeological sites to this reference map to investigate mobility. So far, we have analysed plant and soil samples from ~200 locations across France including the Aquitaine basin, the western and northern parts of the Paris basin, as well as three transects through the Pyrenees Mountains. The isotope data, geologic background information (BRGM 1:1M), field images, and detailed method descriptions are available through our online database iRhum (http://rses.anu.edu.au/research/ee). This database can also be used in forensic studies and food sciences. As an archaeological case study teeth from 16 adult and 8 juvenile individuals were investigated from an early Bell Beaker (2500-2000 BC) site at Le Tumulus des Sables, south-west France (Gironde). The teeth were analysed for Sr isotope ratios using laser ablation ICP-MS. Four teeth were also analysed using solution ICP-MS, which showed a significant offset to the laser ablation results. This requires further

  17. Decay studies of the highly neutron-deficient indium isotopes

    International Nuclear Information System (INIS)

    Wouters, J.M.

    1982-02-01

    An extension of the experimentally known nuclidic mass surface to nuclei far from the region of beta-stability is of fundamental interest in providing a better determination of the input parameters for the various nuclear mass formulae, allowing a more accurate prediction of the ultimate limits of nuclear stability. In addition, a study of the shape of the mass surface in the vicinity of the doubly-closed nuclide 100 Sn provides initial information on the behavior of the shell closure to be expected when Z = N = 50. Experiments measuring the decay energies of 103 105 In by β-endpoint measurements are described with special attention focused on the development of a plastic scintillator β-telescope coupled to the on-line mass separator RAMA (Recoil Atom Mass Analyzer). An attempt to measure the β-endpoint energy of 102 In is also briefly described. The experimentally determined decay energies and derived masses for 103 105 In are compared with the predictions of different mass models to identify which models are more successful in this region. Furthermore, the inclusion in these comparisons of the available data on the neutron-rich indium nuclei permits a systematic study of their ground state mass behavior as a function of the neutron number between the shell closures at N = 50 and N = 82. These analyses indicate that the binding energy of 103 In is 1 MeV larger than predicted by the majority of the mass models. An examination of the Q/sub EC/ surface and the single- and two-neutron separation energies in the vicinity of 103 105 In is also performed to investigate further the deviation and other possible systematic variations in the mass surface in a model-independent way

  18. Effects of Heat Treatment on Raman Spectra of Two-Layer 12C/13C Graphene

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Frank, Otakar; Kavan, Ladislav

    2012-01-01

    Roč. 18, č. 43 (2012), s. 13877-13884 ISSN 0947-6539 R&D Projects: GA AV ČR IAA400400911; GA AV ČR IAA400400804; GA AV ČR KAN200100801; GA MŠk ME09060; GA ČR GAP204/10/1677; GA ČR(CZ) GAP208/12/1062 Institutional support: RVO:61388955 Keywords : graphene * isotopic labeling * layered compounds Subject RIV: CG - Electrochemistry Impact factor: 5.831, year: 2012

  19. Photon strength functions in Gd isotopes studied from radiative capture of resonance neutrons

    Directory of Open Access Journals (Sweden)

    Kroll J.

    2014-04-01

    Full Text Available The experimental spectra of γ rays following radiative neutron capture on isolated resonances of stable 152,154–158Gd targets were measured by the DANCE calorimeter installed at the Los Alamos Neutron Scattering Center in New Mexico, USA. These spectra were analyzed within the extreme statistical model to get new information on the photon strength functions. Special emphasis was put on study of the scissors vibrational mode present in these isotopes. Our data show that the scissors-mode resonances are built not only on the ground states but also on the excited levels of all studied Gd isotopes. The scissors mode strength observed in 157,159Gd products is significantly higher than in neighboring even-even nuclei 156,158Gd. Such a difference indicates the existence of an odd-even effect in the scissors mode strength. Moreover, there exists no universal parameter-free model of the electric dipole photon strength function describing the experimental data in all of the Gd isotopes studied. The results for the scissors mode are compared with the (γ, γ′ data for the ground-state transitions and with the results from 3He-induced reactions.

  20. Ion beam production and study of radioactive isotopes with the laser ion source at ISOLDE

    Science.gov (United States)

    Fedosseev, Valentin; Chrysalidis, Katerina; Day Goodacre, Thomas; Marsh, Bruce; Rothe, Sebastian; Seiffert, Christoph; Wendt, Klaus

    2017-08-01

    At ISOLDE the majority of radioactive ion beams are produced using the resonance ionization laser ion source (RILIS). This ion source is based on resonant excitation of atomic transitions by wavelength tunable laser radiation. Since its installation at the ISOLDE facility in 1994, the RILIS laser setup has been developed into a versatile remotely operated laser system comprising state-of-the-art solid state and dye lasers capable of generating multiple high quality laser beams at any wavelength in the range of 210-950 nm. A continuous programme of atomic ionization scheme development at CERN and at other laboratories has gradually increased the number of RILIS-ionized elements. At present, isotopes of 40 different elements have been selectively laser-ionized by the ISOLDE RILIS. Studies related to the optimization of the laser-atom interaction environment have yielded new laser ion source types: the laser ion source and trap and the versatile arc discharge and laser ion source. Depending on the specific experimental requirements for beam purity or versatility to switch between different ionization mechanisms, these may offer a favourable alternative to the standard hot metal cavity configuration. In addition to its main purpose of ion beam production, the RILIS is used for laser spectroscopy of radioisotopes. In an ongoing experimental campaign the isotope shifts and hyperfine structure of long isotopic chains have been measured by the extremely sensitive in-source laser spectroscopy method. The studies performed in the lead region were focused on nuclear deformation and shape coexistence effects around the closed proton shell Z = 82. The paper describes the functional principles of the RILIS, the current status of the laser system and demonstrated capabilities for the production of different ion beams including the high-resolution studies of short-lived isotopes and other applications of RILIS lasers for ISOLDE experiments. This article belongs to the Focus on

  1. Studies of osteoporosis in Croatia using isotope related techniques

    International Nuclear Information System (INIS)

    Ozegovic, D.D.

    2000-01-01

    Pilot study was held to evaluate bone stiffness in children and adolescents in two districts of Croatia which, according to previous knowledge, differ in calcium intake. The relationship between habitual calcium intake and bone stiffness was determined. It was difficult and expensive to organise a transport of Istrian children to Zagreb in order to perform x-rays absorptiometry. Therefore, bone stiffness was determined with a portable ultrasound system. Bone mineral density (BMD) measurements were continued in subjects of both sex, across the age range 20-50 years from the central district of the city of Zagreb. Subjects were randomly selected from the demographic list. There is a tendency of BMD fall after the age of menopause in women. It appears that peak bone mass in women is obtained in the mid- 20s and In men at 30 years of age. The general conclusion about the trends observed In the population will be given after collection of all data. Calcium intake has an influence on peak bone mass, which becomes evident at the adolescent age. Children who had higher calcium intake had a higher bone mass, although that difference was not statistically significant That finding was more apparent in males. The calcium intake in Zagreb children was higher, so was the energy intake, but the mean body mass Index was identical, which indicates higher physical activity in children from Zagreb. Besides the calcium intake, the role of energy value of the food and habitual physical activities seem to be important in bone maturation

  2. A radiogenic isotope tracer study of transatlantic dust transport from Africa to the Caribbean

    Science.gov (United States)

    Kumar, A.; Abouchami, W.; Galer, S.J.G.; Garrison, V.H.; Williams, E.; Andreae, M.O.

    2014-01-01

    Many studies have suggested that long-range transport of African desert dusts across the Atlantic Ocean occurs, delivering key nutrients and contributing to fertilization of the Amazon rainforest. Here we utilize radiogenic isotope tracers – Sr, Nd and Pb – to derive the provenance, local or remote, and pathways of dust transport from Africa to the Caribbean. Atmospheric total suspended particulate (TSP) matter was collected in 2008 on quartz fibre filters, from both sides of the Atlantic Ocean at three different locations: in Mali (12.6°N, 8.0°W; 555 m a.s.l.), Tobago (11.3°N, 60.5°W; 329 m a.s.l.) and the U.S. Virgin Islands (17.7°N, 64.6°W; 27 m a.s.l.). Both the labile phase, representative of the anthropogenic signal, and the refractory detrital silicate fraction were analysed. Dust deposits and soils from around the sampling sites were measured as well to assess the potential contribution from local sources to the mineral dust collected. The contribution from anthropogenic sources of Pb was predominant in the labile, leachate phase. The overall similarity in Pb isotope signatures found in the leachates is attributed to a common African source of anthropogenic Pb, with minor inputs from other sources, such as from Central and South America. The Pb, Sr and Nd isotopic compositions in the silicate fraction were found to be systematically more radiogenic than those in the corresponding labile phases. In contrast, Nd and Sr isotopic compositions from Mali, Tobago, and the Virgin Islands are virtually identical in both leachates and residues. Comparison with existing literature data on Saharan and Sahelian sources constrains the origin of summer dust transported to the Caribbean to mainly originate from the Sahel region, with some contribution from northern Saharan sources. The source regions derived from the isotope data are consistent with 7-day back-trajectory analyses, demonstrating the usefulness of radiogenic isotopes in tracing dust provenance and

  3. Study on Sr-Nd isotopes of mesozoic-cenozoic granites in Qinghai-Tibetan plateau

    International Nuclear Information System (INIS)

    Qiu Ruizhao; Deng Jinfu; Zhou Su; Xiao Qinghui; Cai Zhiyong

    2003-01-01

    Mesozoic-Cenozoic magmatic activities were intensive in Qinghai-Tibetan plateau. Nd-Sr isotopic compositions of representative granitic plutons in western Qinghai-Tibetan plateau are reported in this paper. Combining with past isotopic data, which has reported in eastern Qinghai-Tibetan plateau, Sr-Nd isotopic compositions and material source and genesis of Mesozoic and Cenozoic granites in Qinghai-Tibetan plateau have been studied. The research result indicates there are three types of granite existing in Qinghai-Tibetan plateau, the granites of Late stage of Yanshan Period which distributing on north and south boundary of Gandes block (namely in north and south granitic belts of Dangdes) and cause of oceanic crust subduction, have ( 87 Sr/ 86 Sr)i of 0.7041-0.7064, ε (Nd) t of +2.5 - +5.7 and TDM age of 312-562 Ma, positive ε Nd, low ( 87 Sr/ 86 Sr)i ratio and young Nd model ages suggest relatively high contents of mantle-derived components in their sources, and this type granite might melt from subduction oceanic crust. The granites occurred intra-Gangdes block which were caused by collision of continent and post-collision, have ( 87 Sr/ 86 Sr)i of 0.706-0.719, ε (Nd) t of -5.3 - -8.3 and TDM age of 1323-1496 Ma, negative ε Nd, relative high ( 87 Sr/ 86 Sr)i ratio with an mid-Proterozoic Nd model ages, suggest granite has the mixing genesis of mantle-derived components and old crustal components in their sources. With relatively small variation range in ε (Nd) t and TDM age, it might imply granitic isotopic source in Gandes block to keep relative homogenization in long period. The granites in Himalayan block which there is not oceanic material to join in melting and to cause of intra-continental subduction, has most ( 87 Sr/ 86 Sr)i ratio more than 0.720, ε (Nd) t of -10.3 - -16.3 and TDM age of 1792-2206 Ma, high ( 87 Sr/ 86 Sr)i ratio, low negative ε (Nd)t with old Nd isotopic model ages and consistent with the Sr, Nd isotopic compositions of basement

  4. A radiogenic isotope tracer study of transatlantic dust transport from Africa to the Caribbean

    Science.gov (United States)

    Kumar, A.; Abouchami, W.; Galer, S. J. G.; Garrison, V. H.; Williams, E.; Andreae, M. O.

    2014-01-01

    Many studies have suggested that long-range transport of African desert dusts across the Atlantic Ocean occurs, delivering key nutrients and contributing to fertilization of the Amazon rainforest. Here we utilize radiogenic isotope tracers - Sr, Nd and Pb - to derive the provenance, local or remote, and pathways of dust transport from Africa to the Caribbean. Atmospheric total suspended particulate (TSP) matter was collected in 2008 on quartz fibre filters, from both sides of the Atlantic Ocean at three different locations: in Mali (12.6°N, 8.0°W; 555 m a.s.l.), Tobago (11.3°N, 60.5°W; 329 m a.s.l.) and the U.S. Virgin Islands (17.7°N, 64.6°W; 27 m a.s.l.). Both the labile phase, representative of the anthropogenic signal, and the refractory detrital silicate fraction were analysed. Dust deposits and soils from around the sampling sites were measured as well to assess the potential contribution from local sources to the mineral dust collected. The contribution from anthropogenic sources of Pb was predominant in the labile, leachate phase. The overall similarity in Pb isotope signatures found in the leachates is attributed to a common African source of anthropogenic Pb, with minor inputs from other sources, such as from Central and South America. The Pb, Sr and Nd isotopic compositions in the silicate fraction were found to be systematically more radiogenic than those in the corresponding labile phases. In contrast, Nd and Sr isotopic compositions from Mali, Tobago, and the Virgin Islands are virtually identical in both leachates and residues. Comparison with existing literature data on Saharan and Sahelian sources constrains the origin of summer dust transported to the Caribbean to mainly originate from the Sahel region, with some contribution from northern Saharan sources. The source regions derived from the isotope data are consistent with 7-day back-trajectory analyses, demonstrating the usefulness of radiogenic isotopes in tracing dust provenance and

  5. Comparative international studies of osteoporosis using isotope techniques

    International Nuclear Information System (INIS)

    Krishnan, S.; Sturtridge, W.C.

    1996-01-01

    In-Vivo Neutron Activation Analysis (IVNAA) and Dual Energy X-ray Absorptiometry (DEXA) are routinely used in our laboratory for clinical and research investigation of Bone Mineral Content (BMC) and Bone Mineral Density (BMD in g/sq.cm). These two techniques differ in many respects. IVNAA is an established technique where 49 Ca radioisotope induced by the 48 Ca(n,gamma) 49 Ca reaction is measured to determine BMC. In DEXA, two X-rays of different energies are used and based on the known attenuation characteristics of bone and soft tissue and the measured attenuated signals, the BMC is calculated. Very little radiation dose (<0.1 mSv) is given in DEXA compared to IVNAA (3 to 5 mSv). Site specific information can be obtained in the former. Although DEXA is easier to use both the techniques are in use in the investigation of Osteopenia. The BMD, a clinical useful parameter, is a function of age and not height. The body calcium content determined by IVNAA is a function of height and not age. These differences are not yet clearly understood. Work is underway to determine the influence of several factors e.g. age, weight on BMD. We are also conducting experiments to determine the peak BMC and BMD of Canadians. The role of various life styles e.g. exercise, diet, ethnicity are being investigated as a determinant of BMD and BMC. Also the effects and safety of many drugs in the treatment of osteopenia and osteoporosis are also being studied. (author)

  6. Charge radii of magnesium isotopes by laser spectroscopy a structural study over the $sd$ shell

    CERN Multimedia

    Schug, M; Krieger, A R

    We propose to study the evolution of nuclear sizes and shapes over the magnesium chain by measuring the root-mean-square charge radii of $^{21 - 32}$Mg, essentially covering the entire $\\textit{sd}$ shell. Our goal is to detect the structural changes, which in the neutron-deficient isotopes may originate from clustering, in a way similar to neon, and on the neutron-rich side would characterize the transition to the "island of inversion". We will combine, for the first time, the sensitive $\\beta$-detection technique with traditional fluorescence spectroscopy for isotope-shift measurements and in such a way gain access to the exotic species near the ${N}$ = 8 and ${N}$ = 20 shell closures.

  7. Chemical and Isotopic Study of the Groundwater of Jeffara Plain of Medenine and Tataouine (Southern Tunisia)

    International Nuclear Information System (INIS)

    Trabelsi, R.; Kalled, M; Zouari, K.; Abidi, B.; Yahyaoui, H.

    2007-01-01

    The study area constitutes the major part of the plain of Jeffara, located at the south-east of Tunisia. This plain is characterized by an arid climate with rare and irregular pluviometry. The hydrochemical approach is used to define the chemical characteristics of the water in these aquifer systems. Indeed, the water salinity varies between 0.6g/? and 9g/?, and increases from the Daher mountains in the west to the Mediterranean Sea. The groundwaters are homogeneous and characterized by a Cl-(SO 4 ) and Na-(Ca-Mg) water type. The isotopic approach shows that the carbone-14 activities, measured in groundwater, evolve in the same direction of groundwater flow. These activities suggest a recent recharge area in eastern piedmont of the Dahar mountains, as well as the zone of the Sahel Abebsa and Zeuss-Koutine. The isotopic values confirm, also, the communication between the various major levels through the existing faults and discontinuities in this area

  8. Isotopic and hydrochemical study of aquifers from Rio Claro District (Sao Paulo State, Brazil)

    International Nuclear Information System (INIS)

    Bonotto, D.N.

    1992-01-01

    An isotopic and hydrochemical study was performed in three aquifers in Rio Claro city area, Sao Paulo State, to establish the chemical facies of the groundwaters and to evaluate the mechanisms of dissolution of the unstable isotope 234 U and 238 U. Mapped groundwater facies were: calcium-bicarbonate for Rio Claro Formation, sodium-nitrate-chloride for fractures in database and sodium-bicarbonate for Tubarao Group. The highest dissolved U contents were measured in groundwaters from the fractured diabase, however, the groundwaters from Tubarao Group showed the highest base-exchange index. Most of the results showed enhancement of 234 U in solution and the highest 234 U/ 238 U activity ratios were measured for groundwaters from Tubarao Group. (author). 33 refs., 5 figs., 1 tab

  9. Experimental study of the higher isotopes of plutonium in the coupled fast-thermal assembly Ermine

    International Nuclear Information System (INIS)

    Bioux, Philippe.

    1973-01-01

    The most important results so far of the plutonium isotopes programme carried out in Ermine are reviewed. The results were obtained on four networks: one with uranium fuel and three with plutonium. The choice of these four networks was essentially based on the energy range of their nuclear reactions, wide enough to include the large reactor energy range, and yet realistic, with a neutron energy distribution in the 4 networks which is never very far from that encountered in a power reactor. The information relative to the high isotopes of plutonium which were obtained in these networks mostly came from: the fission indices measured in the 4 networks, the study of the balance in the two media at k(infinite)=1, reactivity measurements on cell replacements and on various plutonium samples, carried out on the three plutonium fuel networks [fr

  10. Phenomenological study of nuclear structure of neutron-rich 88Rb isotope

    Science.gov (United States)

    Gupta, Surbhi; Gupta, Anuradha; Bharti, Arun

    2018-05-01

    A theoretical study of the nuclear structure of odd-odd 88Rb nucleus in the A ˜100 mass region is carried out by using the angular-momentum-projection technique implemented in the Projected Shell Model (PSM). The influence of the high-j orbitals, h11/2 for neutrons and g9/2 for protons on the structure of 88Rb isotope is investigated in the present case by assuming an axial symmetry in the deformed basis. For this isotope, PSM calculations are performed to obtain the yrast line and also the description of the formation of the yrast level structure from multi-quasi-particle configurations. The back-bending in moment of inertia and transition energies have also been calculated and compared with the experimental data.

  11. Environmental isotopic and hydrochemical study of the coastal submarine springs in Lebanon and Syria

    International Nuclear Information System (INIS)

    Al-Charideh, A. R.

    2007-08-01

    The groundwater of major karst system and the submarine springs in the Syrian coastal limestone aquifer have been studied using chemical and isotopic techniques. Stable isotopes show that the groundwater and submarine springs originates from the direct infiltration of atmospheric water. The elevation of recharge zones feeding the Banyas area (400-600 m a.s.l). The δ 18 O e xtracted for the major submarine spring at Bassieh suggests a mean recharge area elevation of 600-700 m a.s.l. Based on the measured velocity and percentage of fresh water at the submarine springs outlet (Bassieh and Tartous), the estimated discharge rate is 350 million m 3 /y. Adopting a model with exponential time distribution, the mean turnover time of groundwater in the Al-sen spring was evaluated to be 60 years. A value of about 3.7 billion m 3 was obtained for the maximum groundwater reservoir size.(Author)

  12. Isotope-edited proton NMR study on the structure of a pepsin/inhibitor complex

    International Nuclear Information System (INIS)

    Fesik, S.W.; Luly, J.R.; Erickson, J.W.; Abad-Zapatero, C.

    1988-01-01

    A general approach is illustrated for providing detailed structural information on large enzyme/inhibitor complexes using NMR spectroscopy. The method involves the use of isotopically labeled ligands to simplify two-dimensional NOE spectra of large molecular complexes by isotope-editing techniques. With this approach, the backbone and side-chain conformations (at the P 2 and P 3 sites) of a tightly bound inhibitor of porcine pepsin have bene determined. In addition, structural information on the active site of pepsin has been obtained. Due to the sequence homology between porcine pepsin and human renin, this structural information may prove useful for modeling renin/inhibitor complexes with the ultimate goal of designing more effective renin inhibitors. Moreover, this general approach can be applied to study other biological systems of interest such as other enzyme/inhibitor complexes, ligands bound to soluble receptors, and enzyme/substrate interactions

  13. Isotopic and chemical studies of geothermal waters of Northern Areas in Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Dildar Hussain, S; Ahmad, M; Akram, W; Sajjad, M I [Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan); Gonfiantini, R [International Atomic Energy Agency, Vienna (Austria). Isotope Hydrology Section; Tasneem, M A

    1995-02-01

    Northern Areas is one of the major thermal fields of Pakistan with more than two dozen known hot springs having discharge temperature ranging from 35 deg. C to 94 deg. C. Isotopic and chemical techniques applied to study the geothermal fields show that thermal waters are of meteoric origin and can be classified as Na-HCO{sub 3}, Na-SO{sub 4} and mixed type on the basis of their chemical contents. At some places cooling of thermal waters seems to be due to steam separation whereas mixing with fresh cold water is prominent at the remaining sites. The temperatures estimated by isotopic and chemical geothermometers for the two major fields i.e. Tatta Pani and Murtazabad are 83-257 deg. C and 65-296 deg. C respectively. (author). 24 refs, 11 figs, 3 tabs.

  14. Carboniferous Granitoid Magmatism of Northern Taimyr: Results of Isotopic-Geochemical Study and Geodynamic Interpretation

    Science.gov (United States)

    Kurapov, M. Yu.; Ershova, V. B.; Makariev, A. A.; Makarieva, E. V.; Khudoley, A. K.; Luchitskaya, M. V.; Prokopiev, A. V.

    2018-03-01

    Data on the petrography, geochemistry, and isotopic geochronology of granites from the northern part of the Taimyr Peninsula are considered. The Early-Middle Carboniferous age of these rocks has been established (U-Pb, SIMS). Judging by the results of 40Ar/39Ar dating, the rocks underwent metamorphism in the Middle Permian. In geochemical and isotopic composition, the granitic rocks have much in common with evolved I-type granites. This makes it possible to specify a suprasubduction marginal continental formation setting. The existence of an active Carboniferous margin along the southern edge of the Kara Block (in presentday coordinates) corroborates the close relationship of the studied region with the continent of Baltia.

  15. Nuclear structure studies of the neutron-rich Rubidium isotopes using Coulomb excitation

    CERN Multimedia

    Reiter, P; Blazhev, A A; Voulot, D; Meot, V H; Simpson, G S; Georgiev, G P; Gaudefroy, L; Roig, O

    We propose to study the properties of odd-mass neutron-rich rubidium isotopes by the Coulomb-excitation technique, using the Miniball array coupled to the REX-ISOLDE facility. The results from similar measurements from the recent years (e.g. for the odd-mass and the odd-odd Cu isotopes, IS435) have shown the strong potential in such measurements for gaining information both for single-particle-like and collective states in exotic nuclei. Since there is practically no experimental information for excited states in the odd-mass Rb isotopes beyond $^{93}$Rb, the present study should be able to provide new data in a region of spherical ($^{93}$Rb and $^{95}$Rb) as well as well-deformed nuclei ($^{97}$Rb and $^{99}$Rb). Of particular interest is the rapid shape change that occurs when going from $^{95}$Rb (${\\varepsilon}_{2}$=0.06) to $^{97}$Rb (${\\varepsilon}_{2}$=0.3). These results should be of significant astrophysical interest as well, due to the close proximity of the r-process path.

  16. Diet and mobility in Early Medieval Bavaria: a study of carbon and nitrogen stable isotopes.

    Science.gov (United States)

    Hakenbeck, Susanne; McManus, Ellen; Geisler, Hans; Grupe, Gisela; O'Connell, Tamsin

    2010-10-01

    This study investigates patterns of mobility in Early Medieval Bavaria through a combined study of diet and associated burial practice. Carbon and nitrogen isotope ratios were analyzed in human bone samples from the Late Roman cemetery of Klettham and from the Early Medieval cemeteries of Altenerding and Straubing-Bajuwarenstrasse. For dietary comparison, samples of faunal bone from one Late Roman and three Early Medieval settlement sites were also analyzed. The results indicate that the average diet was in keeping with a landlocked environment and fairly limited availability of freshwater or marine resources. The diet appears not to have changed significantly from the Late Roman to the Early Medieval period. However, in the population of Altenerding, there were significant differences in the diet of men and women, supporting a hypothesis of greater mobility among women. Furthermore, the isotopic evidence from dietary outliers is supported by "foreign" grave goods and practices, such as artificial skull modification. These results reveal the potential of carbon and nitrogen isotope analysis for questions regarding migration and mobility. © 2010 Wiley-Liss, Inc.

  17. Study of groundwater chemistry and salinization in Rechna Doab using hydrochemical and isotopic tools

    International Nuclear Information System (INIS)

    Sajjad, M.I.; Tasneem, M.A.; Akram, W.; Ahmad, M.; Hussain, S.D.; Khan, I.H.

    1991-09-01

    Isotopic and chemical characterization of groundwater in Rechna Doab were studied. Samples of water from existing shallow and deep wells, etc. were collected and analyzed for their major ionic and stable isotopic (/sup 2/H, /sup 18/O) contents. The chemical data was used to have a knowledge of various aspects of water chemistry. Different compositional types of water existing in the area were identified. It was observed that groundwater at most of the locations belongs to sodium bicarbonate type. The geochemical evaluation of groundwater was also studied. It is suggested that infiltering water picks up carbon dioxide during percolation through the soil zone. This CO/sub 2/rich water upon interaction with the sediments dissolves more soluble ions. With the increase in salinity soluble remains in solution. Chemical quality of water was evaluated for various uses and found satisfactory in most of the cases. Stable isotopic values in combination with conservative ion (Cl) concentration were used to identify the process of groundwater salinization. Three possible processes, mixing with connate marine water, concentration of salts by evaporation and dissolution of salts from sediments was found to be the operating mechanism under the prevailing conditions. (author)

  18. Quantum Dynamics Study of the Isotopic Effect on Capture Reactions: HD, D2 + CH3

    Science.gov (United States)

    Wang, Dunyou; Kwak, Dochan (Technical Monitor)

    2002-01-01

    Time-dependent wave-packet-propagation calculations are reported for the isotopic reactions, HD + CH3 and D2 + CH3, in six degrees of freedom and for zero total angular momentum. Initial state selected reaction probabilities for different initial rotational-vibrational states are presented in this study. This study shows that excitations of the HD(D2) enhances the reactivities; whereas the excitations of the CH3 umbrella mode have the opposite effects. This is consistent with the reaction of H2 + CH3. The comparison of these three isotopic reactions also shows the isotopic effects in the initial-state-selected reaction probabilities. The cumulative reaction probabilities (CRP) are obtained by summing over initial-state-selected reaction probabilities. The energy-shift approximation to account for the contribution of degrees of freedom missing in the six dimensionality calculation is employed to obtain approximate full-dimensional CRPs. The rate constant comparison shows H2 + CH3 reaction has the biggest reactivity, then HD + CH3, and D2 + CH3 has the smallest.

  19. Final Progress Report: Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes Feasibility Study

    International Nuclear Information System (INIS)

    Rawool-Sullivan, Mohini; Bounds, John Alan; Brumby, Steven P.; Prasad, Lakshman; Sullivan, John P.

    2012-01-01

    This is the final report of the project titled, 'Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes,' PMIS project number LA10-HUMANID-PD03. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). It summarizes work performed over the FY10 time period. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). Human analysts begin analyzing a spectrum based on features in the spectrum - lines and shapes that are present in a given spectrum. The proposed work was to carry out a feasibility study that will pick out all gamma ray peaks and other features such as Compton edges, bremsstrahlung, presence/absence of shielding and presence of neutrons and escape peaks. Ultimately success of this feasibility study will allow us to collectively explain identified features and form a realistic scenario that produced a given spectrum in the future. We wanted to develop and demonstrate machine learning algorithms that will qualitatively enhance the automated identification capabilities of portable radiological sensors that are currently being used in the field.

  20. Bioaccumulation of newly deposited mercury by fish and invertebrates : an enclosure study using stable mercury isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Paterson, M.J.; Blanchfield, P.J.; Podemski, C.; Rudd, J.W.M.; Sandilands, K.A. [Fisheries and Oceans Canada, Winnipeg, MB (Canada). Freshwater Inst.; Hintelmann, H.H.; Ogrinc, N. [Trent Univ., Peterborough, ON (Canada). Dept. of Chemistry; Gilmour, C.C. [Smithsonian Environmental Research Center, Edgewater, MD (United States); Harris, R. [Tetra Tech Inc., Oakville, ON (Canada)

    2006-10-15

    Concentrations of methyl mercury (MeHg) are elevated in fish from North American lakes, which has resulted in the closure of fisheries and the issuance of consumption advisories in many areas. This study investigated the utility of using stable isotopes of enriched stable mercury (Hg) to examine Hg accumulation in aquatic communities. Enriched stable HG isotopes were added to 4 10 m diameter enclosures in an experimental lake to increase inorganic Hg loading. The objective of the study was to trace low-level additions of isotope-enriched Hg through the biogeochemical cycle and into the food web; and to determine the relative contribution of the newly deposited Hg to MeHg accumulation by fish and other biota. The experiment was conducted over 2 summers with a variety of enriched Hg isotopes being added each year. Data suggested that changes in deposition of inorganic Hg will result in changes in MeHg accumulation by fish and other biota. Results showed that within 1 month, spikes of Hg were detected in water, zooplankton, and benthic invertebrates as MeHg, and in fish as total Hg. In 2001, concentrations in water of inorganic spike Hg added in 2000 were near detection limits. Concentrations of 2000 spike MeHg in water and biota remained unchanged or greater. The accumulation of ambient, non-spike MeHg predominated in all organisms despite comparatively large increases in inorganic Hg loading. It was concluded that although long-term changes in Hg deposition may result in changes in MeHg accumulation by biota, it may take upwards of a decade for steady-state conditions to be achieved. Further research is needed to determine to what extent data from the enclosures can be applied to natural lakes. 29 refs., 5 tabs., 5 figs.

  1. Laser-spectroscopic nuclear-structure studies on radioactive silver and indium isotopes

    International Nuclear Information System (INIS)

    Dinger, U.

    1988-05-01

    Neutron-deficient silver and neutron-rich indium isotopes were studied by collinear laser spectroscopy. The neutron-deficient nuclei 101 , 103 , 104 , 105 , 105m , 106m Ag were produced as evaporation-residual nuclei in heavy-ion fusion reactions at the mass separator of the GSI in Darmstadt. The fourteen studied indium isotopes and isomers with even mass number in the range 112-126 In were produced by 600-MeV-proton induced fission of a uranium carbide target at the ISOLDE separator in Geneva. The mass-separated ion beam was subsequently deviated electrostatically, neutralized in a sodium vapor and superposed with a c w dye laser. A photon counting system detected the resonance fluorescence of the induced transitions. The hyperfine structure and the isotope shift of the 4d 9 5s 2 2 D 5/2 → 4d 10 6p 2 P 3/2 transition (λ=547.7 nm) in silver and the 5p 2 P 1/2,3/2 → 6s 2 s 1/2 transition (λ=410 respectively 451 nm) in indium were measured. While in indium for the analysis of the data earlier work could be referred to, in silver a detailed analysis of the isotope shift and hyperfine structure was performed by means of ab initio calculations and semi-empirical procedures. Thereby the configuration interactions were especially considered. The nuclear moments were discussed in the framework of existing nuclear models regarding nuclear-spectroscopic informations. (orig./HSI) [de

  2. The size-isotopic evolution connection among layered mafic instrusions: Clues from a Sr-Nd isotopic study of a small complex

    Science.gov (United States)

    Poitrasson, Franck; Pin, Christian; Duthou, Jean-Louis; Platevoet, Bernard

    1994-05-01

    Several theoretical and experimental works have focused on the processes occuring in continental mafic magma chambers. In contrast, systematic isotopic studies of natural remnants of these latter remain scarce, although they can give fundamental constraints for theoretical studies. This is especially true if different layered complex with contrasting characteristics (e.g., different size) are compared. For this reason, we present the results of a Sr-Nd isotopic profile across a small layered mafic intrusion of Permian age exposed near Fozzano (SW Corsica). In the main zone of the layered section, decreasing Sr-87/Sr(sub i)-86 and increasing Nd-143/Nd(sub i)-144 are observed from less evolved (bottom) to more evolved (top) rocks. This peculiar pattern precludes assimilation and fractional crystallization (AFC) as a dominant mechanism in the petrogenesis of this body. Instead, we interpret this trend as reflecting the dilution of an early stage contaminated magma by several reinjections of fresh basalt in the chamber. In agreement with mineralogical and structural data, every cyclic unit is interpreted as a new magmatic input. On the basis of rough refill and fractional crystallization (RFC) calculations, the average volume for each reinjection is estimated to have been about 0.04 cu km. The cumulative volume of these injections would amount to about 75% of the total volume of the layered complex. This implies that reinjections were accompanied by an important increase of the volume of the chamber or by magma withdrawal by surface eruptions. The RFC mechanism documented within this small layered body constrasts with the isotopic pattern observed between several intrusions at the regional scale in SW Corsica, and within large continental mafic magma chambers elsewhere. In these cases the isotopic evolution is dominated by AFC processes, and there is no clear isotopic evidence for reinjections, unless major influx of fresh magma occurred. It is suggested that there is

  3. Some carbonates from Lagoa Real uranium province, State of Bahia: studies on fluid inclusion and stable isotope

    International Nuclear Information System (INIS)

    Fuzikawa, K.

    1982-01-01

    The geochemical conditions of the uraniferous carbonates of Lagoa Real province were studied using the fluid inclusions method and the isotopic determinations of the carbon and oxygen of these carbonates. (A.B.) [pt

  4. Carnivore specific bone bioapatite and collagen carbon isotope fractionations: Case studies of modern and fossil grey wolf populations

    Science.gov (United States)

    Fox-Dobbs, K.; Wheatley, P. V.; Koch, P. L.

    2006-12-01

    -tissue differences we measured for wolves are applicable to future isotopic studies of consumers with purely carnivorous diets. For example, we collected bone bioapatite and collagen carbon isotope data from late Pleistocene grey wolf fossils from eastern Beringia (Fairbanks, Alaska), and used the modern inter-tissue difference presented here to verify bioapatite preservation. We then compared the wolves to herbivores (horse and caribou) from the same locality, and found the difference in their bone bioapatite carbon isotope values corresponded to the modern carnivore-herbivore trophic spacing given above. We therefore were able to conclude that horse and caribou were part of Beringian wolf diet.

  5. Acetylation of spermidine and methylglyoxal bis(guanylhydrazone) in baby-hamster kidney cells (BHK-21/C13).

    Science.gov (United States)

    Wallace, H M; Nuttall, M E; Robinson, F C

    1988-01-01

    Treatment of BHK-21/C13 cells with methylglyoxal bis(guanylhydrazone) (MGBG) induced the cytosolic form of spermidine N1-acetyltransferase. It stabilized the enzyme against proteolytic degradation, but the drug did not affect the enzyme activity in vitro. MGBG was itself acetylated by BHK-21/C13 cells, but at only one-tenth the rate at which spermidine was acetylated. Acetylation occurred almost exclusively in the nuclear fraction. The product was identified as N-acetyl-MGBG by h.p.l.c., by using [3H]acetyl-CoA and [14C]MGBG as co-substrates. The results suggest that the acetylation of MGBG by BHK-21/C13 cells occurs by a different acetyltransferase enzyme from that which acetylates spermidine. PMID:3421945

  6. Peculiar morphology of the high-redshift radio galaxies 3C 13 and 3C 256 in subarcsecond seeing

    International Nuclear Information System (INIS)

    Le Fevre, O.; Hammer, F.; Nottale, L.; Mazure, A.; Christian, C.

    1988-01-01

    High-spatial-resolution imaging is presented for two radio galaxies from the 3C catalog, 3C 13 and 3C 256 with redshifts of 1.351 and 1.819, respectively. The excellent image quality obtained at CFHT, 0.6-arcsec FWHM for 3C 13 and 0.7-arcsec FWHM for 3C 256 in the R band, over long integration times, made it possible to resolve these distant galaxies into complex structures. As suggested by Le Fevre et al. (1987) for another source (the gravitational lens candidate 3C 324) an interpretation in terms of gravitational amplification by foreground galaxies or clusters of galaxies is proposed. 3C 13 appears to be the most serious candidate, since a foreground galaxy, with an absolute luminosity M(R) = 23.3 and a redshift z = 0.477, is only 3.9 in from the extended radio galaxy. 18 references

  7. Isotopic Evidence for Microbial Activity in Crystalline Bedrock Fractures - a Case Study from Olkiluoto, SW Finland

    Science.gov (United States)

    Sahlstedt, E. K.; Karhu, J.; Pitkänen, P.

    2015-12-01

    Changes in the geochemical environment in crystalline bedrock fractures were investigated using the stable isotopes of C, O and S in fracture filling minerals as tracers. Of special interest were the possible changes which may occur in the subsurface at low temperatures. Especially, the influence of microbial activity was recognized as a catalyst for inducing changes in the geochemical environment. The study site is the Olkiluoto island located on the western coast of Finland, planned to host a geological repository for nuclear waste. Fracture surfaces were investigated to recognize the latest mineralizations at the site. These fillings were comprised of thin plates or small euhedral crystals of calcite and pyrite. The carbon and sulfur isotope compositions of calcite and pyrite were measured from bulk material by conventional IRMS, and in situ by secondary ion mass spectrometry. A notable feature of the late-stage fillings was high variabilities in the δ13C values of calcite and the δ34S values of pyrite, which ranged from -53.8 ‰ to +31.6 ‰ and from -50.4 ‰ to +77.7 ‰, respectively. Based on the isotopic compositions of the fillings, several features in the past hydrogeochemical environment could be recognized. The isotopic composition of the fracture fillings indicate an environment which was stratified with respect to depth. Characteristic features include bacterial sulfate reduction (BSR) occurring at depths 50 m. It appears that methanic conditions were replaced by sulfate reduction at depths >50 m likely due to infiltration of SO42--rich brackish waters. Sulfate reducing bacteria used mainly surface derived organic carbon as electron donors. Some indication of minor methanotrophic activity was recognized in anomalously low δ13C values of calcite, down to -53.8 ‰, at the depth range of 34-54 m. This methanotrophic activity may have been related to bacteria using CH4 as an electron donor in BSR.

  8. Study of peculiarities of hydrogen isotopes mixture permeation through low activated steel F82H

    International Nuclear Information System (INIS)

    Kenzhin, Ye.A.; Tazhibayeva, I.L; Kulsartov, T.V.; Shestakov, V.P.; Chikhray, Ye.V.; Afanasev, S.E.; Zheldak, Yu.L.

    2003-01-01

    Full text: The problem of diffusion tritium leakage through blanket materials of future fusion device makes some constructive difficulties concerned with protection of personnel and environment and also with losses of tritium, which is planned to be used in the same device. One of the little-studied problems in the tritium leakage process in Fusion Power Plant is that in fact tritium will penetrate through materials while other hydrogen isotopes are present. These are deuterium and hydrogen which always are present in metals. Therefore, for evaluation of tritium leakage in future Fusion Power Plant under such conditions it is necessary to have experimental data about permeation of these hydrogen isotopes through the structure materials.One of proposed structure materials of fusion reactor blanket is low activated steel F82H. The experiment results on evaluation of .hydrogen, deuterium and its mixture interaction parameters with steel F82H are shown in this work. The tests were carried out within temperature range 273-973 K under inlet hydrogen pressure of 100-2000 Pa. Diffusivity, deuterium and hydrogen permeation constants for low activated steel F82H was determined from experiment results. Those experimental results were used for created phenomenology model which describes hydrogen isotope penetration through tube sample from hydrogen isotopes mixture. That model was used so determining the ratios of desorption rates (D-D, D-H, H-H) on outlet side of sample. Using of so obtained results, we can correctly evaluate, the titanium leakage from blanket of fusion machine which will be constructed using low activated steel F82H

  9. Isotope techniques in the study of the hydrology of fractured and fissured rocks

    International Nuclear Information System (INIS)

    1989-01-01

    It is generally agreed that the hydrology of fractured rocks refers to the occurrence and movement of groundwater in rocks whose porosity is due to cracks, fissures and fractures in compact rocks. Until recently, crystalline rocks were considered to be impervious (the role of karst reservoirs for groundwater storage is already known). Thus, although fractured rocks cover approximately one-third of the Earth's surface, knowledge of groundwater flow dynamics still needs to be substantively improved. The Proceedings include the papers presented at the Advisory Group Meeting on the Application of Isotope Techniques in the Study of the Hydrology of Fractured and Fissured Rocks, which took place in Vienna from 17 to 21 November 1986. The meeting was attended by 21 scientists from 10 Member States. The Group agreed that the following topics should be given the highest priority: (1) Protection of groundwater resources should be incorporated into all future activities. This implies that recharge areas have to be delineated, not only using nuclear techniques but also other hydrogeological and geochemical methods. Research efforts in this direction should be intensified. (2) The Group was aware that new isotope techniques are being developed in hydrogeology and agreed that their application in fractured and fissured rocks showed promise. It was therefore suggested that information on new isotopes such as 36 Cl and 129 I should be gathered, either in the form of the various techniques currently being used by different laboratories or through the various activities that are being undertaken. Ways of co-ordinating the work being done and exchanging information at the international level should be encouraged. The Proceedings should be of interest to scientists responsible for the evaluation of water resources in crystalline rocks. It is hoped that hydrologists and hydrogeologists working in such terrains who are not familiar with the use of isotope techniques will find ideas and

  10. Preparation of electrodeless discharge lamps for emission studies of uranium isotopes at trace level

    International Nuclear Information System (INIS)

    Bhowmick, G.K.; Verma, R.; Verma, M.K.; Raman, V.A.; Joshi, A.R.; Deo, M.N.; Gantayet, L.M.; Tiwari, A.K.; Ramakumar, K.L.; Kumar, Navin

    2010-01-01

    A simplified method for preparation of electrodeless discharge lamp for uranium isotopes with specific concerns for 232 U is described. Micro-gram quantities of solid uranium oxides and aqueous solution of uranium nitrate have been used as a starting material for in situ synthesis of uranium tetraiodide. High temperature iodination reaction is carried out in the presence of inert gas neon. By careful design, the preparation time and surface area of quartz reaction tubes have been reduced considerably. The latter decreases the level of contamination which has a direct bearing on the operational lifetime of the lamps. Incorporation of steps to purify the product from an unwanted material improved the stability of the lamps. The procedure provides a safe and convenient way of handling 232 U in particular but can be extended in general to any actinides having radioactivity similar to that of freshly separated 232 U. Characteristic emission of uranium isotopes have been recorded by Fourier Transform Spectrometer to show the satisfactory operation of the lamps as well as their usage for studying emission spectra of the specific isotope.

  11. Isotope fractionation of sandy-soil water during evaporation - an experimental study.

    Science.gov (United States)

    Rao, Wen-Bo; Han, Liang-Feng; Tan, Hong-Bing; Wang, Shuai

    2017-06-01

    Soil samples containing water with known stable isotopic compositions were prepared. The soil water was recovered by using vacuum/heat distillation. The experiments were held under different conditions to control rates of water evaporation and water recovery. Recoveries, δ 18 O and δ 2 H values of the soil water were determined. Analyses of the data using a Rayleigh distillation model indicate that under the experimental conditions only loosely bound water is extractable in cases where the recovery is smaller than 100 %. Due to isotopic exchange between vapour and remaining water in the micro channels or capillaries of the soil matrix, isotopic fractionation may take place under near-equilibrium conditions. This causes the observed relationship between δ 2 H and δ 18 O of the extracted water samples to have a slope close to 8. The results of this study may indicate that, in arid zones when soil that initially contains water dries out, the slope of the relationship between δ 2 H and δ 18 O values should be close to 8. Thus, a smaller slope, as observed by some groundwater and soil water samples in arid zones, may be caused by evaporation of water before the water has entered the unsaturated zone.

  12. Isotopic studies of mariposite-bearing rocks from the south- central Mother Lode, California.

    Science.gov (United States)

    Kistler, R.W.; Dodge, F.C.W.; Silberman, M.L.

    1983-01-01

    Gold-bearing vein formation in the Mother Lode belt of the study area apparently occurred during the Early Cretaceous between 127 and 108 m.y. B.P. The hydrothermal fluids that carried the gold precipitated quartz and mariposite at approx 320oC, similar to the T of precipitation of gold-bearing quartz veins in the Allegheny district. The O- and H-isotopic composition calculated for the fluid indicate that it was similar to formation water or was metamorphic in origin. If the carbonate in the veins was in isotopic equilibrium with this same fluid, it apparently precipitated at a higher T of approx 400oC. The Sr in the carbonate is much less radiogenic than that in any known marine carbonate, but is similar in isotopic composition to that in metamorphosed mafic volcanic rocks of the general region. These mafic rocks could have been the source for the Sr in the hydrothermal veins. This observation supports the contention that the gold-mariposite-quartz-carbonate rocks were formed as an alteration product of serpentinite and other mafic igneous rocks.-A.P.

  13. Isotopic studies of marbles in the Sanbagawa metamorphic terrain, central Shikoku, Japan

    International Nuclear Information System (INIS)

    Wada, Hideki; Enami, Masaki; Yanagi, Takeru.

    1984-01-01

    Carbon, oxygen and strontium isotopic studies were carried out on marbles occurring in crystalline schists and epidote amphibolites of the Sanbagawa metamorphic terrain, central Shikoku, Japan, in order to estimate metamorphic temperatures and to elucidate their origin. Carbon isotopic fractionation between calcite and graphite shows the metamorphic temperature of 460 deg C at the transitional part between the garnet and albite-biotite zones. Marbles are isotopically classified into two groups. (1) some marbles in epidote amphibolite masses show characteristically negative delta 13 C values and low 87 Sr/ 86 Sr ratios. These marbles are interpreted as have been derived from magmatic or deep-seated carbonates. (2) marbles collected from the crystalline schists and from the marginal part of epidote amphibolite masses, have high 87 Sr/ 86 Sr ratios and delta 13 C values similar to those of typical sedimentary carbonates. They were probably derived from sedimentary carbonates and/or carbonates re-equilibrated with metamorphic fluid segregated from crystalline schists during the Sanbagawa metamorphism. (author)

  14. Guidelines for the use of isotopes of sulfur in soil-plant studies

    International Nuclear Information System (INIS)

    2003-01-01

    Sulfur (S) is an essential element in plant, human and animal nutrition. This publication provides an overview of the sulfur cycle and how isotopic tracers can be used to obtain unique and precise information on the fluxes and movement of S between and within different compartments of the soil-plant system. It provides information on the theory and measurement of 35S and 34S, safety procedures using 35S, preparation of labelled S fertilizers and plant residues, estimation of the quantity of isotope required for different temporal and spatial scales, preparation digestion /extraction) and analysis of soil and plant samples and guidelines on comparative advantages with non-nuclear techniques and applications, including case studies and references. It is a timely publication in that greater attention is now being focused on S deficiencies in agriculture, which are becoming more common due to reduced atmospheric accretions from industrial sources and to the reduced use of fertilizer materials that contain sulfur as a secondary nutrient. The sub-programme in Soil and Water Management and Crop Nutrition is committed to the dissemination of information to Member States on the practical applications of nuclear techniques through the IAEA Training Course Series. The present publication is preceded by IAEA-TCS-14 (2001), Use of Isotope and Radiation Methods in Soil and Water Management and Crop Nutrition, and IAEA-TCS-16 (2002), Neutron and Gamma Probes: Their Use in Agronomy

  15. Guidelines for the use of isotopes of sulfur in soil-plant studies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-08-01

    Sulfur (S) is an essential element in plant, human and animal nutrition. This publication provides an overview of the sulfur cycle and how isotopic tracers can be used to obtain unique and precise information on the fluxes and movement of S between and within different compartments of the soil-plant system. It provides information on the theory and measurement of 35S and 34S, safety procedures using 35S, preparation of labelled S fertilizers and plant residues, estimation of the quantity of isotope required for different temporal and spatial scales, preparation digestion /extraction and analysis of soil and plant samples and guidelines on comparative advantages with non-nuclear techniques and applications, including case studies and references. It is a timely publication in that greater attention is now being focused on S deficiencies in agriculture, which are becoming more common due to reduced atmospheric accretions from industrial sources and to the reduced use of fertilizer materials that contain sulfur as a secondary nutrient. The sub-programme in Soil and Water Management and Crop Nutrition is committed to the dissemination of information to Member States on the practical applications of nuclear techniques through the IAEA Training Course Series. The present publication is preceded by IAEA-TCS-14 (2001), Use of Isotope and Radiation Methods in Soil and Water Management and Crop Nutrition, and IAEA-TCS-16 (2002), Neutron and Gamma Probes: Their Use in Agronomy.

  16. Study of the subterranean estuary of Venice lagoon using radium and radon isotopes

    International Nuclear Information System (INIS)

    Gattacceca, J.

    2009-02-01

    This study focuses on hydrological processes in the southern part of Venice lagoon (Italy), and more specifically on the interactions between surface waters and groundwater of superficial coastal aquifers. These aquifers present a hydraulic head and a ground level below sea level. Major elements and stable isotopes were used to characterize mixing processes into the superficial aquifer. Our results, in agreement with hydrodynamic modelling, evidenced the restriction of saline intrusion to a narrow coastal fringe (≤ 1 km). Submarine groundwater discharge fluxes into the lagoon were quantified using radium and radon natural isotopes. Their activities in the lagoon are in excess compared to the sea. Our results and preliminary modelling work evidence that the system requires an input from groundwater enriched in these isotopes to explain measured activities. A mass balance at steady state is used to quantify the flux. Results vary between 8.1*10 5 and 1.5*10 7 m 3 .d -1 . This flux is mainly due to recirculation of lagoon water into the sediments, and is 2 to 10 times higher than surface runoff, and may have significant environmental consequences by releasing contaminants. (author)

  17. Utilization of stable isotopes for the study of in vivo compartmental metabolism of poly-insaturate fatty acids

    International Nuclear Information System (INIS)

    Brossard, N.; Croset, M.; Lecerf, J.; Lagarde, M.; Pachiaudi, C.; Normand, S.; Riou, J.P.; Chirouze, V.; Tayot, J.L.

    1994-01-01

    In order to study the compartmental metabolism of the 22:6n-3 fatty acid, and particularly the role of the transport plasmatic forms for the tissue uptake (especially brain), a technique is developed using carbon 13 stable isotope and an isotopic mass spectrometry coupled to gaseous chromatography technique. This method has been validated in rat with docosahexaenoic acid enriched in 13 C and esterified in triglycerides. The compartmental metabolism is monitored by measuring the variation of 22:6n-3 isotopic enrichment in the various lipoprotein lipidic fractions, in blood globules and in the brain. 1 fig., 1 tab., 12 refs

  18. An isotopic and fluid inclusion study of fracture calcite from borehole OL-KR1 at the Olkiluoto site, Finland

    International Nuclear Information System (INIS)

    Blyth, A.; Frape, S.; Blomqvist, R.; Nissinen, P.; McNutt, R.

    1998-04-01

    A study of the geochemistry of fracture filling calcite in borehole OL-KR1 at the radioactive waste disposal investigation site Olkiluoto (in Finland) was undertaken in 1998. The purpose of the present study is to characterize the fracture calcite using mineralogy, oxygen, carbon and strontium isotopes, and fluid inclusions in order to determine past and present chemical and isotopic condition at the site

  19. An isotopic and fluid inclusion study of fracture calcite from borehole OL-KR1 at the Olkiluoto site, Finland

    Energy Technology Data Exchange (ETDEWEB)

    Blyth, A.; Frape, S. [Univ. of Waterloo, ON (Canada); Blomqvist, R.; Nissinen, P. [Geological Survey of Finland, Espoo (Finland); McNutt, R. [McMaster Univ. of Hamilton, ON (Canada)

    1998-04-01

    A study of the geochemistry of fracture filling calcite in borehole OL-KR1 at the radioactive waste disposal investigation site Olkiluoto (in Finland) was undertaken in 1998. The purpose of the present study is to characterize the fracture calcite using mineralogy, oxygen, carbon and strontium isotopes, and fluid inclusions in order to determine past and present chemical and isotopic condition at the site 39 refs.

  20. Application of 18O and 2H natural isotopes for groundwater study in Semarang Basin, Central Java

    International Nuclear Information System (INIS)

    Rasi Prasetio; Satrio

    2015-01-01

    As a big city that support industrialism, Semarang has increasing needs of fresh water supply which is mostly provided by ground water. The utilization of groundwater must consider sustainability and environmental preservation aspects, as water is basic needs for human being. Therefore, the knowledge about groundwater dynamics is important to manage groundwater utilization. Isotope hydrology technique using 18 O and 2 H isotopes has been applied to investigate groundwater dynamics and can be taken as consideration for groundwater management. For this purpose, water samples have been collected from various water sources such as springs, deep monitoring wells, dug wells, streams and rain water for 18 O and 2 H isotopes analysis. The results show that isotopes composition of groundwater varied between -8.77‰ to -4.76‰ for δ 18 O and -56.6‰ to -29.4‰ for δ 2 H. Isotopes composition for unconfined groundwater in most of study area are relatively uniform, i.e. between -5.9‰ to -6.6‰ for δ 18 O and -35.1‰ to -40.4‰ for δ 2 H, except in some minor places that have more depleted and more enriched composition. This distribution indicates that the unconfined aquifer is depend on local recharge. While most of isotopes composition of deep confined aquifer plotted around isotopes composition of Ungaran's rain water, indicates that the recharge area of these confined groundwater were originated from this elevation or higher. (author)

  1. The mechanism of oxygen isotopic fractionation during fungal denitrification - A pure culture study

    Science.gov (United States)

    Wrage-Moennig, Nicole; Rohe, Lena; Anderson, Traute-Heidi; Braker, Gesche; Flessa, Heinz; Giesemann, Annette; Lewicka-Szczebak, Dominika; Well, Reinhard

    2014-05-01

    Nitrous oxide (N2O) from soil denitrification originates from bacteria and - to an unknown extent - also from fungi. During fungal denitrification, oxygen (O) exchange takes place between H2O and intermediates of the denitrification process as in bacterial exchange[1,2]. However, information about enzymes involved in fungal O exchanges and the associated fractionation effects is lacking. The objectives of this study were to estimate the O fractionation and O exchange during the fungal denitrifying steps using a conceptual model[2] adapted from concepts for bacterial denitrification[3], implementing controls of O exchange proposed by Aerssens, et al.[4] and using fractionation models by Snider et al.[5] Six different pure fungal cultures (five Hypocreales, one Sordariales) known to be capable of denitrification were incubated under anaerobic conditions, either with nitrite or nitrate. Gas samples were analyzed for N2O concentration and its isotopic signatures (SP, average δ15N, δ18O). To investigate O exchange, both treatments were also established with 18O-labelled water as a tracer in the medium. The Hypocreales strains showed O exchange mainly at NO2- reductase (Nir) with NO2- as electron acceptor and no additional O exchange at NO3- reductase (Nar) with NO3- as electron acceptor. The only Hypocreales species having higher O exchange with NO3- than with NO2- also showed O exchange at Nar. The Sordariales species tested seems capable of O exchange at NO reductase (Nor) additionally to O exchange at Nir with NO2-. The data will help to better interpret stable isotope values of N2O from soils. .[1] D. M. Kool, N. Wrage, O. Oenema, J. Dolfing, J. W. Van Groenigen. Oxygen exchange between (de)nitrification intermediates and H2O and its implications for source determination of NO?3- and N2O: a review. Rapid Commun. Mass Spec. 2007, 21, 3569. [2] L. Rohe, T.-H. Anderson, B. Braker, H. Flessa, A. Giesemann, N. Wrage-Mönnig, R. Well. Fungal Oxygen Exchange between

  2. A Combined Radio- and Stable-Isotopic Study of a California Coastal Aquifer System

    Directory of Open Access Journals (Sweden)

    Michael Land

    2013-04-01

    Full Text Available Stable and radioactive tracers were utilized in concert to characterize geochemical processes in a complex coastal groundwater system and to provide constraints on the kinetics of rock/water interactions. Groundwater samples from wells within the Dominguez Gap region of Los Angeles County, California were analyzed for a suite of major cations (Na+, K+, Mg2+, Ca2+ and anions (Cl−, SO42−, silica, alkalinity, select trace elements (Ba, B, Sr, dissolved oxygen, stable isotopes of hydrogen (δD, oxygen (δ18O, dissolved inorganic carbon (δ13CDIC, and radioactive isotopes (3H, 222Rn and 223,224,226,228Ra. In the study area, groundwater may consist of a complex mixture of native groundwater, intruded seawater, non-native injected water, and oil-field brine water. In some wells, Cl− concentrations attained seawater-like values and in conjunction with isotopically heavier δ18O values, these tracers provide information on the extent of seawater intrusion and/or mixing with oil-field brines. Groundwater 3H above 1 tritium unit (TU was observed only in a few select wells close to the Dominguez Gap area and most other well groundwater was aged pre-1952. Based on an initial 14C value for the study site of 90 percent modern carbon (pmc, groundwater age estimates likely extend beyond 20 kyr before present and confirm deep circulation of some native groundwater through multiple aquifers. Enriched values of groundwater δ13CDIC in the absence of SO42− imply enhanced anaerobic microbial methanogenesis. While secular equilibrium was observed for 234U/238U (activity ratios ~1 in host matrices, strong isotopic fractionation in these groundwater samples can be used to obtain information of adsorption/desorption kinetics. Calculated Ra residence times are short, and the associated desorption rate constant is about three orders of magnitude slower than that of the adsorption rate constant. Combined stable- and radio-isotopic results provide unique insights

  3. Stable isotope distribution in precipitation in Romania and its relevance for palaeoclimatic studies

    Science.gov (United States)

    Perşoiu, Aurel; Nagavciuc, Viorica; Bădăluţă, Carmen

    2014-05-01

    A surge of recent studies in Romania have targeted various aspects of palaeoclimate (based on stable isotopes in ice, speleothems, tree rings), mineral water origin, wine and other juices provenance. However, while much needed, these studies lack a stable isotope in precipitation background, with only two LMWL's being published so far. In this paper we discuss the links between the stable isotopic composition of precipitation (δ18O and δ2H), climate (air temperature, precipitation amount and large scale circulation) and their relevance for the palaeocllimatic interpretation of stable isotope values in cave ice, cryogenic calcite and tree rings from different sites in Romania. Most of the precipitation in Romania is delivered by the Westerlies, bringing moisture from the North Atlantic; however, their influence is greatly reduced in the eastern half of the country where local evaporative sources play an important role in the precipitation balance. The SW is dominated by water masses from the Mediterranean Sea, while the SE corner clearly draws most of the moisture from the Black Sea and strongly depleted North Atlantic vapor masses. In 2012, Romania experienced the worst draught in 60 years, possibly due to a northward shift of the jest stream associated to blocking conditions in summer, which led to a more northern penetration of the Mediterranean-derived air masses, as well increased precipitation of re-evaporated waters. We have further analyzed cave drip water (δ18O and δ2H), cryogenic cave calcite (δ18O and δ13C) and tree rings (δ18O and δ13C) from selected sites across NW Romania, where the water isotopes in precipitation showed the best (and easiest to understand, given the climatic conditions in 2012) correlation with climatic parameters. Our results that 1) δ18O and δ2H in cave ice are a good proxy for late summer through early winter air temperature; 2) δ13C in cryogenic cave calcite are possible indicators of soil humidity and 3) δ18O in pine

  4. Surface studies of water isotopes in Antarctica for quantitative interpretation of deep ice core data

    Science.gov (United States)

    Landais, Amaelle; Casado, Mathieu; Prié, Frédéric; Magand, Olivier; Arnaud, Laurent; Ekaykin, Alexey; Petit, Jean-Robert; Picard, Ghislain; Fily, Michel; Minster, Bénédicte; Touzeau, Alexandra; Goursaud, Sentia; Masson-Delmotte, Valérie; Jouzel, Jean; Orsi, Anaïs

    2017-07-01

    Polar ice cores are unique climate archives. Indeed, most of them have a continuous stratigraphy and present high temporal resolution of many climate variables in a single archive. While water isotopic records (δD or δ18O) in ice cores are often taken as references for past atmospheric temperature variations, their relationship to temperature is associated with a large uncertainty. Several reasons are invoked to explain the limitation of such an approach; in particular, post-deposition effects are important in East Antarctica because of the low accumulation rates. The strong influence of post-deposition processes highlights the need for surface polar research programs in addition to deep drilling programs. We present here new results on water isotopes from several recent surface programs, mostly over East Antarctica. Together with previously published data, the new data presented in this study have several implications for the climatic reconstructions based on ice core isotopic data: (1) The spatial relationship between surface mean temperature and mean snow isotopic composition over the first meters in depth can be explained quite straightforwardly using simple isotopic models tuned to d-excess vs. δ18O evolution in transects on the East Antarctic sector. The observed spatial slopes are significantly higher (∼ 0.7-0.8‰·°C-1 for δ18O vs. temperature) than seasonal slopes inferred from precipitation data at Vostok and Dome C (0.35 to 0.46‰·°C-1). We explain these differences by changes in condensation versus surface temperature between summer and winter in the central East Antarctic plateau, where the inversion layer vanishes in summer. (2) Post-deposition effects linked to exchanges between the snow surface and the atmospheric water vapor lead to an evolution of δ18O in the surface snow, even in the absence of any precipitation event. This evolution preserves the positive correlation between the δ18O of snow and surface temperature, but is

  5. Isotope exchange study of the dissociation of metal-humic complexes

    International Nuclear Information System (INIS)

    Mizera, J.; Jansova, A.; Hvozdova, I.; Benes, P.

    2002-01-01

    Prediction of the migration of toxic metals and radionuclides in the environment requires knowledge of equilibrium and kinetic parameters characterising their interaction with humic substance (HS). In this work, isotope exchange of Eu and Co in the systems containing HS has been used to study dissociation of the cations from their complexes with HS under quasi-stationary conditions. In the experimental arrangement of the so-called diaphragm method, a dialysis membrane divides two compartments containing solutions of metal and HS, identical in both half-cells but for radiolabeling ( 152 Eu and 60 Co) applied only in one cell. The membrane is permeable for free metal cation but not for the metal-HS complex. The slow dissociation of metal cation from HS is reflected by retardation (compared to a reference system in the absence of HS) of the rate of the isotope exchange between the two compartments. However, only an apparent dissociation rate can be observed, as detection of fast dissociation is limited by the rate of diffusion of dissociated cations through membrane and by their recombination with available binding sites of HS. The rate of isotope exchange of Eu and Co in the systems with HS (Aldrich sodium humate, soil humic and fulvic acid) was monitored as function of pH (4 and 6), ionic strength (0.01 and 0.1 M), and the degree of HS loading with metal ([M] 0 = 10 -7 - 2x10 -5 M at 10 mg/L HS). For Co, the rate of 60 Co 2+ diffusion through the membrane showed up to control the rate of the isotope exchange indicating that the Co-HS dissociation is too fast to be followed by the diaphragm method, and that the abundance of non-complexed Co is not negligible. The apparent rate of Eu-HS dissociation was found to be enhanced by decreasing pH value, increasing ionic strength, and increasing metal loading (i.e., metal/HS ratio). For interpretation of the experimental kinetic data, a discrete 2-component model (bi-exponential decay function) was applied. Based on

  6. Isotopes in heterogeneous catalysis

    CERN Document Server

    Hargreaves, Justin SJ

    2006-01-01

    The purpose of this book is to review the current, state-of-the-art application of isotopic methods to the field of heterogeneous catalysis. Isotopic studies are arguably the ultimate technique in in situ methods for heterogeneous catalysis. In this review volume, chapters have been contributed by experts in the field and the coverage includes both the application of specific isotopes - Deuterium, Tritium, Carbon-14, Sulfur-35 and Oxygen-18 - as well as isotopic techniques - determination of surface mobility, steady state transient isotope kinetic analysis, and positron emission profiling.

  7. Geochemistry of silicon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

    2018-04-01

    Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

  8. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  9. Oxygen isotope study of the Long Valley magma system, California: isotope thermometry and convection in large silicic magma bodies

    Science.gov (United States)

    Bindeman, Ilya; Valley, John

    2002-07-01

    Products of voluminous pyroclastic eruptions with eruptive draw-down of several kilometers provide a snap-shot view of batholith-scale magma chambers, and quench pre-eruptive isotopic fractionations (i.e., temperatures) between minerals. We report analyses of oxygen isotope ratio in individual quartz phenocrysts and concentrates of magnetite, pyroxene, and zircon from individual pumice clasts of ignimbrite and fall units of caldera-forming 0.76 Ma Bishop Tuff (BT), pre-caldera Glass Mountain (2.1-0.78 Ma), and post-caldera rhyolites (0.65-0.04 Ma) to characterize the long-lived, batholith-scale magma chamber beneath Long Valley Caldera in California. Values of δ18O show a subtle 1‰ decrease from the oldest Glass Mountain lavas to the youngest post-caldera rhyolites. Older Glass Mountain lavas exhibit larger ( 1‰) variability of δ18O(quartz). The youngest domes of Glass Mountain are similar to BT in δ18O(quartz) values and reflect convective homogenization during formation of BT magma chamber surrounded by extremely heterogeneous country rocks (ranging from 2 to +29‰). Oxygen isotope thermometry of BT confirms a temperature gradient between "Late" (815 °C) and "Early" (715 °C) BT. The δ18O(quartz) values of "Early" and "Late" BT are +8.33 and 8.21‰, consistent with a constant δ18O(melt)=7.8+/-0.1‰ and 100 °C temperature difference. Zircon-melt saturation equilibria gives a similar temperature range. Values of δ18O(quartz) for different stratigraphic units of BT, and in pumice clasts ranging in pre-eruptive depths from 6 to 11 km (based on melt inclusions), and document vertical and lateral homogeneity of δ18O(melt). Worldwide, five other large-volume rhyolites, Lava Creek, Lower Bandelier, Fish Canyon, Cerro Galan, and Toba, exhibit equal δ18O(melt) values of earlier and later erupted portions in each of the these climactic caldera-forming eruptions. We interpret the large-scale δ18O homogeneity of BT and other large magma chambers as evidence

  10. Isotope exchange study of nickel xanthate in presence of aniline and isomeric toluidines

    International Nuclear Information System (INIS)

    Naidu, G.R.K.; Naidu, P.R.

    1982-01-01

    Isotopic exchange behaviour of nickel xanthate is studied in the presence of aniline and three isomeric toluidines at 18degC. The effect of base concentration is also studied on the exchange rate. The results show that the complex is labile in the kinetic sense in the presence of aniline meta and para toluidines. The rate of exchange increases with and para toluidines. The rate of exchange increases with increase in concentration of the base. The complex displays inert behaviour in the presence of o-toluidine and it is ascribed to dominant steric effect. (author)

  11. Study of neutron-rich $^{51−53}$ Ca isotopes via $\\beta$-decay

    CERN Multimedia

    The high Q$_\\beta$ values in certain neutron-rich regions of the chart of nuclides opens up the possibility to study states in the daughter nuclei which lie at high excitation energy, above the neutron separation threshold. We propose to perform spectroscopy of the $\\beta$-delayed neutron emission of the $^{51-53}$K isotopes to study the population of single-particle or particle-hole states both below and above the neutron separation threshold. The VANDLE neutron detector will be used in combination with the IDS tape station setup and Ge detectors.

  12. Hydrochemical and isotopic studies in two neighboring river basins in semiarid regions of Minas Gerais

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Vinícius G.; Moreira, Rubens M.; Carvalho, Carlos A., E-mail: vinicius.ferreira@cdtn.br, E-mail: rubens@cdtn.br, E-mail: cacf@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Serviço de Meio Ambiente

    2017-07-01

    Groundwater is the largest reservoir of fresh water on Earth and the depletion of aquifer systems is a reality, both in semi-arid and humid regions. The hydrology of watersheds is a field of study that is concerned with the movement of waters from the rains and its physical-chemical changes. Groundwater resources in these regions are a sensitive issue, requiring careful management to avoid quality degradation. The present study focuses the groundwater system at the interface of the Pandeiros and Peruaçu river basins in the northwest region of Minas Gerais State. The methods used were the evaluations of the hydrochemistry, as well as isotopic, and physicochemical parameters, allied to geological studies to investigate surface and groundwater, their possible interactions and spatial distribution. The hydrochemical results correlated with the physicochemical measurements show water contrasts in the study area, which is geologically composed from bottom to top by gneisses and granites (Januaria Complex), limestone and siltstones (Bambuí Group), sandstones and eluvial sediments (Urucuia Group), eluvio-coluvial cover and alluvial deposits. It has been observed that waters in the context of sandstones and siliceous sediments are sodium bicarbonate waters, slightly acidic pH and low in TDS, whereas waters in pedological / geologic context of limestones are calcium bicarbonate waters exhibiting basic pH and high TDS. The deuterium (D) and oxygen-18 signatures of the groundwater are compared to the global meteoric water line (GMWL). The average values of the isotopes in the study area are slightly variable, indicating that the isotopic signatures are related to rainfall precipitation. It has been possible to suggest an evaporation line pattern starting from the position of springs, passing though streams and finally ending in the lagoon. The local evaporation line can be represented by the equation δD = 5,8 δ{sup 18}O - 2,4. (author)

  13. Neutronic and thermal-hydraulic studies of aqueous homogeneous reactor for medical isotopes production

    International Nuclear Information System (INIS)

    Perez, Daniel Milian; Lorenzo, Daniel E. Milian; Lira, Carlos A. Brayner de Oliveira; Garcia, Lorena P. Rodríguez; Universidade Federal de Pernambuco

    2017-01-01

    The use of Aqueous Homogenous Reactors (AHR) is one of the most promissory alternatives to produce medical isotopes, mainly "9"9Mo. Compare to multipurpose research reactors, an AHR dedicated for "9"9Mo production has advantages because of their low cost, small critical mass, inherent passive safety, and simplified fuel handling, processing, and purification characteristics. This article presents the current state of research in our working group on this topic. Are presented and discussed the group validation efforts with benchmarking exercises that include neutronic and thermal-hydraulic results of two solution reactors, the SUPO and ARGUS reactors. Neutronic and thermal-hydraulic results of 75 kWth AHR based on the ARGUS reactor LEU configuration are presented. The neutronic studies included the determination of parameters such as reflector thickness, critical height, medical isotopes production and others. Thermal-hydraulics studies were focused on demonstrating that sufficient cooling capacity exists to prevent fuel overheating. In addition, the effects of some calculation parameters on the computational modeling of temperature, velocity and gas volume fraction during steady-state operation of an AHR are discussed. The neutronic and thermal-hydraulics studies have been performed with the MCNPX version 2.6e computational code and the version 14 of ANSYS CFX respectively. Our group studies and the results obtained contribute to demonstrate the feasibility of using AHR for the production of medical isotopes, however additional studies are still necessary to confirm these results and contribute to development and demonstration of their technical, safety, and economic viability. (author)

  14. Neutronic and thermal-hydraulic studies of aqueous homogeneous reactor for medical isotopes production

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Daniel Milian; Lorenzo, Daniel E. Milian; Lira, Carlos A. Brayner de Oliveira; Garcia, Lorena P. Rodríguez, E-mail: milianperez89@gmail.com, E-mail: dmilian@instec.cu, E-mail: lorenapilar1109@gmail.com, E-mail: cabol@ufpe.br [Higher Institute of Technologies and Applied Sciences (InSTEC), Havana (Cuba); Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

    2017-11-01

    The use of Aqueous Homogenous Reactors (AHR) is one of the most promissory alternatives to produce medical isotopes, mainly {sup 99}Mo. Compare to multipurpose research reactors, an AHR dedicated for {sup 99}Mo production has advantages because of their low cost, small critical mass, inherent passive safety, and simplified fuel handling, processing, and purification characteristics. This article presents the current state of research in our working group on this topic. Are presented and discussed the group validation efforts with benchmarking exercises that include neutronic and thermal-hydraulic results of two solution reactors, the SUPO and ARGUS reactors. Neutronic and thermal-hydraulic results of 75 kWth AHR based on the ARGUS reactor LEU configuration are presented. The neutronic studies included the determination of parameters such as reflector thickness, critical height, medical isotopes production and others. Thermal-hydraulics studies were focused on demonstrating that sufficient cooling capacity exists to prevent fuel overheating. In addition, the effects of some calculation parameters on the computational modeling of temperature, velocity and gas volume fraction during steady-state operation of an AHR are discussed. The neutronic and thermal-hydraulics studies have been performed with the MCNPX version 2.6e computational code and the version 14 of ANSYS CFX respectively. Our group studies and the results obtained contribute to demonstrate the feasibility of using AHR for the production of medical isotopes, however additional studies are still necessary to confirm these results and contribute to development and demonstration of their technical, safety, and economic viability. (author)

  15. Stable isotope and hydrogeochemical studies of Beaver Lake and Lake Radok, MacRobertson Land, East Antarctica

    International Nuclear Information System (INIS)

    Wand, U.; Hermichen, W.D.; Hoefling, R.; Muehle, K.

    1987-01-01

    Beaver Lake and Lake Radok, the largest known epishelf and the deepest freshwater lake on the Antarctic continent, respectively, were isotopically (δ 2 H, δ 18 O) and hydrogeochemically studied. Lake Radok is an isothermal and non-stratified, i.e. homogeneous water body, while Beaver Lake is stratified with respect to temperature, salinity and isotopic composition. The results for the latter attest to freshwater (derived from snow and glacier melt) overlying seawater. (author)

  16. Stable isotope and hydrogeochemical studies of Beaver Lake and Radok Lake, MacRobertson Land, East Antarctica

    International Nuclear Information System (INIS)

    Wand, U.; Hermichen, W.D.

    1988-01-01

    Beaver Lake and Radok Lake, the largest known epishelf lake and the deepest freshwater lake on the Antarctic continent, respectively, were isotopically (δ 2 H, δ 18 O) and hydrogeochemically studied. Radok Lake is an isothermal and nonstratified, i.e. homogeneous water body, while Beaver Lake is stratified with respect to temperature, salinity and isotopic composition. The results for the latter attest to freshwater (derived from snow and glacier melt) overlying seawater. (author)

  17. Fundamental studies in isotope chemistry. Progress report, 1 August 1981-1 August 1982

    International Nuclear Information System (INIS)

    Bigeleisen, J.

    1982-01-01

    This research program is concerned with isotope chemistry and its applications. A summary of isotope separation activities during the past 5 years is included. Isotope effects are used as probes for chemical reactions, geochemistry, meteorology, and molecular biology, and this report also summarizes progress made in this area

  18. High-precision mass spectrometric analysis using stable isotopes in studies of children

    NARCIS (Netherlands)

    Schierbeek, Henk; van den Akker, Chris H. P.; Fay, Laurent B.; van Goudoever, Johannes B.

    2012-01-01

    The use of stable isotopes combined with mass spectrometry (MS) provides insight into metabolic processes within the body. Herein, an overview on the relevance of stable isotope methodology in pediatric research is presented. Applications for the use of stable isotopes with MS cover carbohydrate,

  19. International conference on the study of environmental change using isotope techniques. Book of extended synopses

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-04-01

    This publication contains extended synopses of the oral and poster presentations delivered at the meeting. The main topics of the meeting included: Isotopes in the atmosphere and the hydrosphere; Interaction between the atmosphere and the hydrosphere; Isotope indicators of past climatic and environmental changes; and Advances in isotope and other analytical techniques. The individual papers have been indexed separately.

  20. International conference on the study of environmental change using isotope techniques. Book of extended synopses

    International Nuclear Information System (INIS)

    2001-04-01

    This publication contains extended synopses of the oral and poster presentations delivered at the meeting. The main topics of the meeting included: Isotopes in the atmosphere and the hydrosphere; Interaction between the atmosphere and the hydrosphere; Isotope indicators of past climatic and environmental changes; and Advances in isotope and other analytical techniques. The individual papers have been indexed separately

  1. Insights into iron sources and pathways in the Amazon River provided by isotopic and spectroscopic studies

    Science.gov (United States)

    Mulholland, Daniel Santos; Poitrasson, Franck; Boaventura, Geraldo Resende; Allard, Thierry; Vieira, Lucieth Cruz; Santos, Roberto Ventura; Mancini, Luiz; Seyler, Patrick

    2015-02-01

    The present study investigated the weathering and transport mechanisms of Fe in the Amazon River. A particular emphasis was placed on Fe partitioning, speciation, and isotopic fractionation in the contrasting waters of the Solimões and Negro rivers and their mixing zone at the beginning of the Amazon River. Samples collected in the end-member rivers and thirteen sites distributed throughout the mixing zone were processed through frontal vacuum filtration and tangential-flow ultrafiltration to separate the different suspended solid fractions, i.e., particulate (P > 0.45 μm and P > 0.22 μm), colloidal (0.22 μm > C > 5 kDa) and truly dissolved elements (TD particulate fractions yielded light isotopic compositions of -0.344‰ for P > 0.22 μm and -0.104‰ for P > 0.45 μm fractions). The mineral particulate-rich waters of the Solimões River had dissolved and colloidal fractions with light isotopic composition (-0.532‰ and -0.176‰, respectively), whereas the particulate fractions yielded δ57Fe values close to those of the continental crust (i.e., -0.029‰ for P > 0.22 μm and 0.028‰ for P > 0.45 μm). Ten kilometers downstream from the Negro and Solimões junction, the concentrations of colloidal and dissolved Fe species deviate markedly from conservative mixing. A maximum Fe loss of 43 μg/L (i.e., 50% of the dissolved and colloidal Fe) is observed 110 km downstream from the rivers junction. The contrasting Negro and Solimões Rivers isotopic compositions along the pore-sized water fractions is attributable to the biogeochemical processes involving different types of upland soils and parental materials. For instance, the isotopic composition of colloidal and dissolved Fe from the Negro River are consistent with Fe oxidation and complexation mechanisms at the interface between waterlogged podzols and river networks, as supported by strong organo-Fe complexes signals observed by EPR. Conversely, the particulate and colloidal fractions from the Solim

  2. Carbon Isotope Chemistry in Molecular Clouds

    Science.gov (United States)

    Robertson, Amy N.; Willacy, Karen

    2012-01-01

    Few details of carbon isotope chemistry are known, especially the chemical processes that occur in astronomical environments like molecular clouds. Observational evidence shows that the C-12/C-13 abundance ratios vary due to the location of the C-13 atom within the molecular structure. The different abundances are a result of the diverse formation pathways that can occur. Modeling can be used to explore the production pathways of carbon molecules in an effort to understand and explain the chemical evolution of molecular clouds.

  3. AKR1B10 induces cell resistance to daunorubicin and idarubicin by reducing C13 ketonic group

    International Nuclear Information System (INIS)

    Zhong Linlin; Shen Honglin; Huang Chenfei; Jing, Hongwu; Cao Deliang

    2011-01-01

    Daunorubicin, idarubicin, doxorubicin and epirubicin are anthracyclines widely used for the treatment of lymphoma, leukemia, and breast, lung, and liver cancers, but tumor resistance limits their clinical success. Aldo-keto reductase family 1 B10 (AKR1B10) is an NADPH-dependent enzyme overexpressed in liver and lung carcinomas. This study was aimed to determine the role of AKR1B10 in tumor resistance to anthracyclines. AKR1B10 activity toward anthracyclines was measured using recombinant protein. Cell resistance to anthracycline was determined by ectopic expression of AKR1B10 or inhibition by epalrestat. Results showed that AKR1B10 reduces C13-ketonic group on side chain of daunorubicin and idarubicin to hydroxyl forms. In vitro, AKR1B10 converted daunorubicin to daunorubicinol at V max of 837.42 ± 81.39 nmol/mg/min, K m of 9.317 ± 2.25 mM and k cat /K m of 3.24. AKR1B10 showed better catalytic efficiency toward idarubicin with V max at 460.23 ± 28.12 nmol/mg/min, K m at 0.461 ± 0.09 mM and k cat /K m at 35.94. AKR1B10 was less active toward doxorubicin and epirubicin with a C14-hydroxyl group. In living cells, AKR1B10 efficiently catalyzed reduction of daunorubicin (50 nM) and idarubicin (30 nM) to corresponding alcohols. Within 24 h, approximately 20 ± 2.7% of daunorubicin (1 μM) or 23 ± 2.3% of idarubicin (1 μM) was converted to daunorubicinol or idarubicinol in AKR1B10 expression cells compared to 7 ± 0.9% and 5 ± 1.5% in vector control. AKR1B10 expression led to cell resistance to daunorubicin and idarubicin, but inhibitor epalrestat showed a synergistic role with these agents. Together our data suggest that AKR1B10 participates in cellular metabolism of daunorubicin and idarubicin, resulting in drug resistance. These data are informative for the clinical use of idarubicin and daunorubicin. - Highlights: → This study defines enzyme activity of AKR1B10 protein towards daunorubicin, idarubicin, doxorubicin, and epirubicin. → This study pinpoints

  4. Nuclear structure studies on indium and tin isotope chains by means of laser spectroscopy

    International Nuclear Information System (INIS)

    Eberz, J.

    1986-11-01

    In a collaboration with GSI in Darmstadt and ISOLDE in Geneva the hyperfine structure (HFS) and the isotope shift (IS) of the indium isotopes from 104 In - 127 In in their ground and isomeric states could be studied. Additionally the tin isotopes 109 Sn and 111 Sn could be measured. In tin the transition 5p 2 1 S 0 → 5p6s 3 P 1 with λ = 563 nm was studied. In indium the transition 5p 2 P 1/2 → 6s 2 S 1/2 with λ = 410 nm and 5p 2 P 3/2 → 6s 2 S 1/2 with λ = 451 nm could be measured. The magnetic dipole moments and electric quadrupole moments determined from the measurements of the HFS can be sufficiently explained in the framework of the single-particle model. From the moments the configurations and spins of the studied nuclear states can be stated. In 109 Sn the nuclear spin was determined to I = 5/2. The measurement of the IS in two lines in 108 In allowed regarding the coupling rules for nuclear moments the determination of the nuclear spin. The spin of the 40 m isomers of the 108m In can be stated to I = 2. The mean square nuclear charge radius exhibits a parabolic slope the quadratic part of which with a maximum in the shell center at N = 66 between the neutron numbers N = 50 and N = 82 can be understood as sum of contributions of a surface correlation, i.e. a quadrupole deformation as well as eventually present higher order terms or a change of the surface skin density. The deformation determinable by this description is both for tin and for indium essentially larger than the deformation from the B(E2) values of tin or from the intrinsic quadrupole moments in indium derived from the HFS. (orig./HSI) [de

  5. ForCent model development and testing using the Enriched Background Isotope Study experiment

    Energy Technology Data Exchange (ETDEWEB)

    Parton, W.J.; Hanson, P. J.; Swanston, C.; Torn, M.; Trumbore, S. E.; Riley, W.; Kelly, R.

    2010-10-01

    The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could accurately simulate ecosystem carbon dynamics for the Oak Ridge National Laboratory deciduous forest. A comparison of ForCent versus observed soil pool {sup 14}C signature ({Delta} {sup 14}C) data from the Enriched Background Isotope Study {sup 14}C experiment (1999-2006) shows that the model correctly simulates the temporal dynamics of the {sup 14}C label as it moved from the surface litter and roots into the mineral soil organic matter pools. ForCent model validation was performed by comparing the observed Enriched Background Isotope Study experimental data with simulated live and dead root biomass {Delta} {sup 14}C data, and with soil respiration {Delta} {sup 14}C (mineral soil, humus layer, leaf litter layer, and total soil respiration) data. Results show that the model correctly simulates the impact of the Enriched Background Isotope Study {sup 14}C experimental treatments on soil respiration {Delta} {sup 14}C values for the different soil organic matter pools. Model results suggest that a two-pool root growth model correctly represents root carbon dynamics and inputs to the soil. The model fitting process and sensitivity analysis exposed uncertainty in our estimates of the fraction of mineral soil in the slow and passive pools, dissolved organic carbon flux out of the litter layer into the mineral soil, and mixing of the humus layer into the mineral soil layer.

  6. Alpha decay studies on Po isotopes using different versions of nuclear potentials

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, K.P.; Sukumaran, Indu [Kannur University, School of Pure and Applied Physics, Payyanur, Kerala (India)

    2017-12-15

    The alpha decays from {sup 186-224}Po isotopes have been studied using 25 different versions of nuclear potentials so as to select a suitable nuclear potential for alpha decay studies. The computed standard deviation of the calculated half-lives in comparison with the experimental data suggested that proximity 2003-I is the apt form of nuclear potential for alpha decay studies as it possesses the least standard deviation, σ = 0.620. Among the different proximity potentials, proximity 1966 (σ = 0.630) and proximity 1977 (σ = 0.636), are also found to work well in alpha decay studies with low deviation. Among other versions of nuclear potentials (other than proximity potentials), Bass 1980 is suggested to be a significant form of nuclear potential because of its good predictive power. However, while the other forms of potentials are able to reproduce the experimental data to some extent, these potentials cannot be considered as apposite potentials for alpha decay studies in their present form. Since the experimental correlation of the models is noticed to be satisfying, the alpha decay half-lives of certain Po isotopes that are not detected experimentally yet have been predicted. (orig.)

  7. Isotope techniques in studies of selenium deficiency and toxicity syndromes in farm animals

    International Nuclear Information System (INIS)

    Giese, W.W.

    1984-01-01

    In a brief review of the Se deficiency syndrome in ruminants, studies using non-isotopic methods are applied to an introductory description of the disease. They include methods currently applied for determining Se deficiency status in feed and in ruminant animals. Detection of potential white muscle disease in lambs and calves is discussed. The application of 75 Se in studies on absorption, tissue distribution and excretion under feeding regimes with different Se levels and partly with addition of SO 4 ions or vitamin E is reviewed. In vitro studies with 75 Se include a description of the 75 Se uptake test with red blood cells, the metabolism of selenite, selenate and selenomethionine in rumen microorganisms, and the distribution of 75 Se in cow's and goat's milk. Methods of Se supplementation in Se-deficient areas are summarized and tests with 75 Se-labelled ruminal pellets in sheep and cattle are described. The Se toxicity syndrome is surveyed with respect to causative agents, symptomatology and gross pathology. Special reference is made to the blind staggers and the alkali disease types of selenosis. Isotope techniques are found to be less frequently applied in studies on Se toxicity than in Se deficiency studies. (author)

  8. Modeling study of vibrational photochemical isotope enrichment. [HBr + Cl/sub 2/; HCl + Br/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Badcock, C.C.; Hwang, W.C.; Kalsch, J.F.

    1978-09-29

    Chemical kinetic modeling studies of vibrational-photochemical isotope enrichment have been performed on two systems: Model (I), H/sup 79/Br(H/sup 81/Br) + Cl/sub 2/ and, Model (II), H/sup 37/Cl(H/sup 35/Cl) + Br. Pulsed laser excitation was modeled to the first excited vibrational level of H/sup 79/Br in Model I and the first and second excited vibrational levels of both HCl isotopes in Model II. These are prototype systems of exoergic (Model I) and endoergic (Model II) reactions. The effects on enrichment of varying the external parameters (pressure, laser intensity) and the internal parameters (rate constants for V-V exchange and excited-state reactions) were examined. Studies of these prototype systems indicate that a favorable reaction for enrichment, with isotopically-specific excitation and a significantly accelerated vibrationally-excited-state reaction should have the following properties: the reaction from v = 0 should be only moderately exoergic, and the most favorable coreactant should be a polyatomic species, such as alkyl radical. Direct excitation of the reacting vibrational level is at least an order of magnitude more favorable for enrichment than is population by energy transfer. Enrichment of the minor isotope by these processes is more effective than is major isotope enrichment. Within limits, increased laser intensity is beneficial. However, for sequential excitation of a second vibrational level, major isotope enrichment can be diminished by high populations of the first vibrational level.

  9. Study of intramolecular isotope heterogeneity of organic oxy acids in order to detect sophisticated wines and juice drinks

    Directory of Open Access Journals (Sweden)

    Kuzmina Helen

    2014-01-01

    Full Text Available According to International Code of Oenological Practices it is allowed to use acide L(+tartrique for wine acidification, while use of synthetic dihydroxysuccinic acid is forbidden. Today it is impossible to differentiate natural dihydroxysuccinic acid from synthetic one by standard techniques. Even by using very sensitive method of isotope mass spectrometry certain difficulties emerge because total isotope characteristics of carbon of dihydroxysuccinic acid of different nature have the same values. However, isotope characteristics of carbon of intramolecular structural groups of dihydroxysuccinic acid made of different raw materials differ significantly. This allows specifying the nature of dihydroxysuccinic acid that is used for making of wines and juice drinks. In Russia, scientific and research institute of beer brewing and wine-making industry carried out a work for studying isotope characteristics of intramolecular isotope heterogeneity of dihydroxysuccinic acid from different origins in order to identify wines and juice drinks. Isotope characteristics of organic oxy acids from different origins were studied including them obtained by synthetic way and numeric range of value δ13 C,‰ were specified. The obtained results allow performing identification tests of wines and juice drinks to find out the products that contain not specified additives as that allowed for its use in production process.

  10. The study of stability of Pt-SDB in isotopic exchange between tritium oxide and hydrogen

    International Nuclear Information System (INIS)

    Dan Guiping

    2008-06-01

    The stability of Pt-SDB on its catalytic activity and the Pt contained in Pt-SDB have been studied during three years in isotopic exchange between tritium oxide and hydrogen. The convert efficiency of the catalyst declined 10% in first two years and then it is 2% after another two years, when it is used interruptedly. The losing of Pt on Pt-SDB is separately 9.09% and 2.31% after it is washed 2000 hours by water and immersed in water 525 days. (authors)

  11. Food authenticity studies via multi-elemental and isotopic pattern using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Katona, R.; Brunner, M.; Abranko, L.; Prohaska, T.; Stefanka, Z.

    2009-01-01

    Full text: The aim of our study has been the development of an analytical method based on Sr isotope and elemental fingerprint analysis for discriminating food samples from different geographical origin. Several types of foods were involved in the investigation representing different stages of food processing such as pulverized spicy paprika (sparsely processed food product) and wine samples (processed product). Independent inorganic mass spectrometric techniques like ICP-SFMS, ICP-CCMS, and MC-ICPMS were used for method validation and investigation of the geographical origin. The advantage and limitations of the developed methods are discussed critically. (author)

  12. 2H Stable Isotope Analysis of Tooth Enamel: A Pilot Study

    Science.gov (United States)

    Holobinko, Anastasia; Kemp, Helen; Meier-Augenstein, Wolfram; Prowse, Tracy; Ford, Susan

    2010-05-01

    Stable isotope analysis of biogenic tissues such as tooth enamel and bone mineral has become a well recognized and increasingly important method for determining provenance of human remains, and has been used successfully in bioarchaeological studies as well as forensic investigations (Lee-Thorp, 2008; Meier-Augenstein and Fraser, 2008). Particularly, 18O and 2H stable isotopes are well established proxies as environmental indicators of climate (temperature) and source water and are therefore considered as indicators of geographic life trajectories of animals and humans (Hobson et al., 2004; Schwarcz and Walker, 2006). While methodology for 2H analysis of human hair, fingernails, and bone collagen is currently used to determine geographic origin and identify possible migration patterns, studies involving the analysis of 2H in tooth enamel appear to be nonexistent in the scientific literature. The apparent lack of research in this area is believed to have two main reasons. (1) Compared to the mineral calcium hydroxylapatite Ca10(PO4)6(OH)2, in tooth enamel forming bio-apatite carbonate ions replace some of the hydroxyl ions at a rate of one CO32 replacing two OH, yet published figures for the degree of substitution vary (Wopenka and Pasteris, 2005). (2) Most probably due to the aforementioned no published protocols exist for sample preparation and analytical method to obtain δ2H-values from the hydroxyl fraction of tooth enamel. This dilemma has been addressed through a pilot study to establish feasibility of 2H stable isotope analysis of ground tooth enamel by continuous-flow isotope ratio mass spectrometry (IRMS) coupled on-line to a high-temperature conversion elemental analyzer (TC/EA). An array of archaeological and modern teeth has been analyzed under different experimental conditions, and results from this pilot study are being presented. References: Lee-Thorp, J.A. (2008) Archaeometry, 50, 925-950 Meier-Augenstein, W. and Fraser, I. (2008) Science & Justice

  13. Further studies of neutron-deficient Sn-isotopes using REX-ISOLDE

    CERN Multimedia

    Larsen, A; Syed naeemul, H; Siem, S

    2007-01-01

    Encouraged by the committee to submit the latter part of our latest addendum to experiment IS418 under a new heading this proposal focuses on the second physics case mentioned there. We propose to use Coulomb excitation of odd mass neutron-deficient Sn isotopes to study some dominantly "one quasi-particle" states in these nuclei. Due to spin selection rules these states are difficult to populate following either $\\beta$-decay or in a cascade after a fusion-evaporation reactions, whereas the excitation from the ground-state is of E2 character for some of the most interesting cases.

  14. Radiogenic age and isotopic studies: report 9. Current research 1995-F

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    `Radiogenic Age and Isotopic Studies` is an annual collection of research presentations containing U-Pb, Sm-Nd, Rb-Sr, and {sup 40}Ar-{sup 39}Ar data generated by the Geochronology Laboratory under the auspices of the Continental Geoscience Division, Geological Survey of Canada. Report 9 contains 5 papers from regions across Canada, followed by a compilation of {sup 40}Ar-{sup 39}Ar and K-Ar ages. Authors herein present data, relate results to field settings, and make brief interpretations. Readers are thus reminded that much of the research encompassed represents `work-in-progress` and that more extensive publications may follow at a later date.

  15. Study of the coefficient of separation for some processes which are applied to lithium isotopes

    International Nuclear Information System (INIS)

    Perret, L.; Rozand, L.; Saito, E.

    1958-01-01

    The fundamental separation factors of some processes are investigated: the distillation of metallic lithium, counter current electromigration in fused salts (particularly in lithium nitrate) electrolysis in aqueous solution and ion exchange. The chemical transfer between a lithium amalgam and lithium salts in a dimethylformamide solution (a solvent which is not attacked by the amalgam) is also studied. Finally a description is given of isotopic analyses carried out either by scintillation counting or by mass spectrography using apparatus specially designed for this particular task. (author) [fr

  16. Radiogenic age and isotopic studies: report 9. Current research 1995-F

    International Nuclear Information System (INIS)

    1996-01-01

    'Radiogenic Age and Isotopic Studies' is an annual collection of research presentations containing U-Pb, Sm-Nd, Rb-Sr, and 40 Ar- 39 Ar data generated by the Geochronology Laboratory under the auspices of the Continental Geoscience Division, Geological Survey of Canada. Report 9 contains 5 papers from regions across Canada, followed by a compilation of 40 Ar- 39 Ar and K-Ar ages. Authors herein present data, relate results to field settings, and make brief interpretations. Readers are thus reminded that much of the research encompassed represents 'work-in-progress' and that more extensive publications may follow at a later date

  17. [Applications of stable isotope analysis in the trophic ecology studies of cephalopods].

    Science.gov (United States)

    Li, Yun-Kai; Gong, Yi; Chen, Xin-Jun

    2014-05-01

    Cephalopods play an important role in marine food webs, however, knowledge about their complex life history, especially their feeding ecology, remains limited. With the rapidly increasing use of stable isotope analysis (SIA) in ecology, it becomes a powerful tool and complement of traditional methods for investigating the trophic ecology and migration patterns of invertebrates. Here, after summarizing the current methods for trophic ecology investigation of cephalopods, applications of SIA in studying the trophic ecology of cephalopods were reviewed, including the key issues such as standardization of available tissues for SIA analyzing, diet shift and migration patterns of cephalopods, with the aim of advancing its application in the biology of cephalopods in the future.

  18. Towards 100Sn: Studies on neutron-deficient even isotopes of tin

    International Nuclear Information System (INIS)

    Rathke, G.E.

    1987-02-01

    Neutron-deficient 108,106,104 Sn isotopes were produced by heavy ion induced fusion reactions using high-intensity 59 Ni beams from the UNILAC of the GSI. Their decay properties were studied by techniques of gamma and conversion electron spectroscopy employing the mass separator on-line to the UNILAC. Earlier information on the 108 Sn → 108 In and 106 Sn → 106 In decays was complemented and improved in the course of this work. The new nucleus 104 Sn and its decay to excited states in 104 In was identified and studied for the first time. These investigations yield the following results: the mass of 104 Sn and of nuclei linked to it by alpha decay or proton radioactivity, 108 Te, 112 Xe and 109 I, 113 Cs, respectively were determined from the measured Q EC value of 104 Sn and the known mass value of 104 In. These are nuclei very close or beyond the proton drip line. In addition, information on the quenching of the fast Gamow-Teller beta decay of the even neutron-deficient tin isotopes was obtained. This complements investigations on the N = 50 isotones 94 Ru and 96 Pd, and allows a systematic comparison of these transition strengths for nuclei near the doubly magic 100 Sn. The spreading of the vertical strokeπg 9/2 -1 vg 7/2 , 1 + > configuration over several states, due to residual interactions, and the centroid energies of these magnetic dipole states were determined for the corresponding odd-odd indium isotopes. (orig./HSI)

  19. Isotopic study of the effect of Tarbela reservoir on the groundwater system in the downstream areas

    International Nuclear Information System (INIS)

    Sajjad, M.I.; Tasneem, M.A.; Hussain, S.D.; Khan, I.H.; Ali, M.; Latif, Z.

    1994-04-01

    Isotopic studies were carried out on the right side of river Indus, downstream of Tarbela dam to study the effect of Tarbela Reservoir on the groundwater system. The main objectives of the study were to determine the hydraulic connection, if any, between the Tarbela Lake and the groundwater appearing in the ponds near Gadon Amazai, see the effect of Tarbela dam on the groundwater system in the downstream areas, compute the relative contribution of different recharge sources towards groundwater system and to estimate residence time of groundwater in the area. Isotopic data reveals that the ponds near Gadoon Amazai area are being recharged by local rains and there is no contribution of Tarbela lake. The area around Gadoon Amazai, Topi and Kalabat is solely recharged by local rains while the area around Swabi, Zaida and Lahor has mixed recharge with major contribution from local canal system. Tritium data suggests that the residence time of groundwater in the study area varies from a few years to 30 years. Te groundwater in the area has low dissolved salt contents and is, generally, of good quality. (author) 19 figs

  20. Study of the matrix specific mass discrimination effects during inductively coupled plasma mass spectrometry isotope ratio measurements

    International Nuclear Information System (INIS)

    Vassileva, E.; Quetel, Ch.R.

    2004-01-01

    Sample matrix related effects on mass discrimination during inductively coupled plasma mass spectrometry (ICP-MS) isotope ratio measurements have only been rarely reported. However, they can lead to errors larger than the uncertainty claimed on the ratio results when not properly taken into account or corrected for. These matrix specific affects were experienced during an Isotope Dilution Mass Spectrometry (IDMS) campaign we carried out for the certification of the Cd amount content in some food digest samples (7% acidity and salts content around 450μg g -1 ). Dilution was not possible for Cd only present at the low ng g -1 level. Up to 1% difference was observed on Cd isotope ratio results between measurements performed directly or after matrix separation. This was a significant difference considering that less than 1.5% relative combined uncertainty was eventually estimated for these IDMS measurements. Similar results could be obtained either way after the implementation of necessary corrections. The direct measurement approach associated to a correction for mass discrimination effects using the food digest sample itself (and the IUPAC table values as reference for the natural Cd isotopic composition) was preferred as it was the easiest. Consequently, the impact of matrix effects on mass discrimination during isotope ratio measurements with two types of ICP- MS (quadrupole and magnetic sector instruments) was studied for 4 elements (Li, Cu, Cd and Tl). Samples of varying salinity (up to 0.25%) and acidity (up to 7%) characteristics were prepared using isotopic certified reference materials of these elements. The long term and short-term stability, respectively reproducibility and repeatability, of the results, as well as the evolution of the difference to certified ratio values were monitored. As expected the 13 investigated isotopic ratios were all sensitive to variations in salt and acid concentrations. Our experiments also showed that simultaneous variation