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Sample records for ams 14c dating

  1. 14C AMS dating Yongcheon cave

    International Nuclear Information System (INIS)

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

  2. {sup 14}C AMS dating Yongcheon cave

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

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

  3. AMS14C dating and stable isotope plots of Late Pleistocene ice-wedge ice

    International Nuclear Information System (INIS)

    Strategy for AMS14C dating of organic micro inclusions from syngenetic ice-wedge ice is considered. AMS14C dates are interpreted in terms of fictitious aging of ice-wedge and permafrost sediments due to high concentration of allochthonous organic material. The dating of organic material from small sample, gives the reliable 14C age. The 14C dates from syngenetic ice-wedges are compared with the dates of the host sediments surrounding syngenetic ice wedges. AMS14C dating of small samples of ice-wedge ice yields to set δ18O plots from ice-wedges to the time scale and to correlate them with ice core δ18O record

  4. Laser AMS 14C dating of rock surface accretions

    International Nuclear Information System (INIS)

    Full text: Equipment has been purchased using a large Earth Sciences and Engineering ARC grant and installed in the Department of Anthropology and Archaeology, James Cook University. A krypton-ion laser used initially at Laval University, Quebec to demonstrate the potential of focusing light energy to induce oxidation of carbon-bearing substances has been replaced by a carbon dioxide laser. This decision was based on reducing the startup cost at James Cook University, increasing options for a wide range of output power, considerations for future applications and the cost of gas refills. A disadvantage of using the carbon dioxide laser is that non-visible light optics are needed because of the infrared output wavelength from the carbon dioxide. This has required the replacement of the glass window of the vacuum-tight micro-combustion chamber with a sodium chloride window and placing the equipment in a dehumidifier room. Laser light power experiments have so far been conducted on optimising the output from the laser and minimising the focal waist of the beam by adjusting the focusing mirrors and lenses. The aim of developing a focused laser system is to enable the dating of carbon in finely laminated rock surface accretions, but before this can be achieved a series of tests is planned to ensure that the focused laser system totally converts all the carbon-bearing substances under the beam into carbon dioxide. This is essential in order that the isotopic values representative of the carbon in the accretions is converted into carbon dioxide. Known quantities of graphite, charcoal, wood cellulose and calcium oxalate salts are being subjected to focused laser combustion or decomposition and the volumes of gas produced at different light powers are being measured. Isotopic measurements are also being conducted on the resulting gases to ensure that fractionation of carbon isotopes is not a problem. The paper will describe the arrangement of equipment and explain the

  5. High-resolution AMS 14C dating of post-bomb peat archives of atmospheric pollutants

    DEFF Research Database (Denmark)

    Goodsite, Michael E.; Rom, Werner; Heinemeier, Jan; Lange, Todd; Ooi, Suat; Appleby, Peter G.; Shotyk, William; Van Der Knaap, W. O.; Lohse, Christian; Hansen, Torben S.

    Peat deposits in Greenland and Denmark were investigated to show that high-resolution dating of these archives of atmospheric deposition can be provided for the last 50 years by radiocarbon dating using the atmospheric bomb pulse. 14C was determined in macrofossils from sequential one cm slices...... using accelerator mass spectrometry (AMS). Values were calibrated with a general-purpose curve derived from annually averaged atmospheric 14CO2 values in the northernmost northern hemisphere (NNH, 30°-90°N). We present a thorough review of 14C bomb-pulse data from the NNH including our own measurements...... range of the bomb-pulse (from the mid-1950s on). Comparing the 14C AMS results with the customary dating method for recent peat profiles by 210Pb, we show that the use of 137Cs to validate and correct 210Pb dates proves to be more problematic than previously supposed. As a unique example of our...

  6. AMS 14C dating at CIRCE: The Major Temple in Cumae (NA - Italy)

    Science.gov (United States)

    Capano, M.; Rescigno, C.; Sirleto, R.; Passariello, I.; Marzaioli, F.; D'Onofrio, A.; Terrasi, F.

    2015-10-01

    We present here one recent CIRCE (Centre for Isotopic Research on Cultural and Environmental Heritage) - Caserta (Italy) project on cultural heritage field, analysing several mice bones, discovered in the Major Temple on the acropolis of Cumae (Napoli, Southern Italy). The bones were found in a vase linked to the holy context. In order to know their dating and formulate an hypothesis on their presence on the site, if it was an accidental rodent inclusion (believed on the base of archaeological context to have occurred during building abandonment periods (IV-V or XIII centuries AD)) or an intentional and ritual remain, the bones were 14C dated by AMS at CIRCE. The results indicate that the mice bones date to the IV century BC and are contemporaneous with building construction. This dating seems to exclude an accidental rodent presence and it supports the hypothesis of Apollo veneration in the temple, based on the already known link between mice and Apollo worship rituals.

  7. Development of a nanofiltration method for bone collagen 14C AMS dating

    Science.gov (United States)

    Boudin, Mathieu; Boeckx, Pascal; Buekenhoudt, Anita; Vandenabeele, Peter; Van Strydonck, Mark

    2013-01-01

    Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased 14C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) ∼100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used. In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate. Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. 14C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant but incomplete

  8. Development of a nanofiltration method for bone collagen {sup 14}C AMS dating

    Energy Technology Data Exchange (ETDEWEB)

    Boudin, Mathieu, E-mail: mathieu.boudin@ugent.be [Royal Institute for Cultural Heritage, Jubelpark 1, B-1000 Brussels (Belgium); Ghent University, Faculty of Bioscience Engineering, Laboratory of Applied Physical Chemistry, Coupure Links 653, B-9000 Ghent (Belgium); Boeckx, Pascal [Ghent University, Faculty of Bioscience Engineering, Laboratory of Applied Physical Chemistry, Coupure Links 653, B-9000 Ghent (Belgium); Buekenhoudt, Anita [Flemish Institute for Technological Research, Separation and Conversion Technology, Boeretang 200, B-2400 Mol (Belgium); Vandenabeele, Peter [Ghent University, Department of Archaeology, Sint-Pietersnieuwstraat 35, B-9000 Ghent (Belgium); Van Strydonck, Mark [Royal Institute for Cultural Heritage, Jubelpark 1, B-1000 Brussels (Belgium)

    2013-01-15

    Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased {sup 14}C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) {approx}100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used. In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate. Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. {sup 14}C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant

  9. Development of a nanofiltration method for bone collagen 14C AMS dating

    International Nuclear Information System (INIS)

    Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased 14C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) ∼100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used. In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate. Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. 14C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant but incomplete

  10. 14C-AMS at the Leibniz-Labor: radiometric dating and isotope research

    International Nuclear Information System (INIS)

    The Leibniz-Labor was founded to provide radiometric dating services using AMS and measured over 15 000 samples and 26 800 targets up to September 2002. Research and development have primarily been directed at improving the efficiency and reliability of AMS measurements, optimising existing sample preparation procedures for AMS and developing new ones. The standard chemical pre-treatment of organic radiocarbon samples produces often two fractions: one from which contaminants have been removed, and one in which they have been enriched. Dating both fractions reveals the degree of sample contamination. This provides a useful indication of the reliability of the sample age obtained and of the environmental conditions where the sample was taken. Upgrades to reduce maintenance include replacing four cryo- by turbo pumps, installing a deionizer loop, which keeps conductivity between 100 and 150 μS/cm to control corrosion, in the closed cooling water circuit, and developing a new sample wheel, which holds target holders with a groove and spring clip. Long term stability is demonstrated by the results obtained for IAEA reference materials, measured routinely and regularly over the years. Tests made as part of the FIRI project demonstrate that reliable measurements down to <0.1 mg C can be made

  11. 14C AMS dating of fires in the central Amazon rain forest

    International Nuclear Information System (INIS)

    Soil samples were collected in tierra firme upland and lowland areas of the Km 41 reserve near Manaus (20 deg. 30'S and 60 deg. W), in Central Brazilian Amazon, within a 1700 m transect, at eight different depth ranges, from surface to 100 cm. The highest charcoal concentrations were found at the depth range of 20-50 cm. AMS radiocarbon dating of 31 samples were performed at the ANU. The ages of the charcoals were found to vary within the 130 to 2400 years BP range, mostly between 1200 and 1400 years BP, one of the known Holocene dry periods of the Amazon region. The results show that the fires have regional dimensions and are associated with climate regional changes

  12. The contribution of 14C AMS dating to the Greater Angkor archaeological project

    Science.gov (United States)

    Zoppi, U.; Barbetti, M.; Fletcher, R.; Hua, Q.; Chhem, R. K.; Pottier, C.; Watanasak, M.

    2004-08-01

    For well over five centuries, the Khmer kingdom ruled over a vast territory, including most of what is now known as Cambodia, Thailand, Vietnam and Laos. Between the 9th and 14th century AD, the Khmer Kings developed the Angkor area into a remarkable administrative and religious centre for their society. According to new estimates by the Greater Angkor Project, the entire urban complex of the capital city covered about 1000 square km making it probably the largest archaeological site in the world. Great stone temples and some other monumental structures and earthworks are the only visible remains of this fascinating civilisation. Thankfully, there is a substantial on-going multinational effort to preserve and restore what is left and in 1992 UNESCO (United Nations Educational Scientific and Cultural Organisation) declared Angkor a World Heritage Site. This paper presents two particular aspects of the Greater Angkor Project where radiocarbon dating by AMS specifically added to our knowledge of the history of this ancient capital city.

  13. The contribution of 14C AMS dating to the Greater Angkor archaeological project

    International Nuclear Information System (INIS)

    For well over five centuries, the Khmer kingdom ruled over a vast territory, including most of what is now known as Cambodia, Thailand, Vietnam and Laos. Between the 9th and 14th century AD, the Khmer Kings developed the Angkor area into a remarkable administrative and religious centre for their society. According to new estimates by the Greater Angkor Project, the entire urban complex of the capital city covered about 1000 square km making it probably the largest archaeological site in the world. Great stone temples and some other monumental structures and earthworks are the only visible remains of this fascinating civilisation. Thankfully, there is a substantial on-going multinational effort to preserve and restore what is left and in 1992 UNESCO (United Nations Educational Scientific and Cultural Organisation) declared Angkor a World Heritage Site. This paper presents two particular aspects of the Greater Angkor Project where radiocarbon dating by AMS specifically added to our knowledge of the history of this ancient capital city

  14. The AMS 14C dating of Iron Age rice chaff ceramic temper from Ban Non Wat, Thailand: First results and its interpretation

    Science.gov (United States)

    Higham, Charles F. W.; Kuzmin, Yaroslav V.; Burr, G. S.

    2010-04-01

    Pottery tempered with rice chaff from the early Iron Age cemetery of Ban Non Wat site, northeast Thailand, has been subjected to direct AMS 14C dating, using low temperature combustion with oxygen as originally developed by authors. The carbon yield (0.2-0.5%) testifies the suitability of this pottery for dating. However, not all the results are in agreement with expected archaeological ages and other 14C dates from the studied site and neighboring site of Noen U-Loke. This calls for a thorough analysis and interpretation of pottery temper dates from the region.

  15. The AMS 14C dating of Iron Age rice chaff ceramic temper from Ban Non Wat, Thailand: First results and its interpretation

    International Nuclear Information System (INIS)

    Pottery tempered with rice chaff from the early Iron Age cemetery of Ban Non Wat site, northeast Thailand, has been subjected to direct AMS 14C dating, using low temperature combustion with oxygen as originally developed by authors. The carbon yield (0.2-0.5%) testifies the suitability of this pottery for dating. However, not all the results are in agreement with expected archaeological ages and other 14C dates from the studied site and neighboring site of Noen U-Loke. This calls for a thorough analysis and interpretation of pottery temper dates from the region.

  16. Reliable 14-C AMS dates on bird and Pacific rat Rattus exulans bone gelatin, from a CaCO3-rich deposit

    International Nuclear Information System (INIS)

    We tested the reliability of accelerator mass spectrometry (AMS) radiocarbon dates on bone gelatin by dating samples whose maximum or minimum age was constrained by stratigraphic position relative to well-dated volcanic tephra layers. The tephra layers were not reworked, and were thick enough to preclude the possibility of redeposition resulting in specimens being found outside the age bounds set by the tephras. The damp, fossiliferous, carbonate-rich sediment was in a relatively constant, cool environment in a small cave at nearly 900 m altitude. Bones from four species of bird with different diets (a pigeon, a rail, an owlet-nightjar, and a large ratite) and one rodent, the Pacific rate Rattus exulans, were dated. The calibrated (calendar) AMS age of each bone was compared to ages predicted from their stratigraphic position and calculated sedimentation rates, inferred from the age of each tephra layer. Samples of moa (Aves: Dinornithiformes) eggshell were also dated by AMS, providing an independent dating material. None of the bone gelatin or eggshell dates displayed any significant in-built (reservoir) age relative to the marker horizons, nor were any AMS ages significantly younger than expected. Our results agree with previous studies in showing that 14C AMS dates on bone gelatin from deposits that have always had a relatively cool, and stable physical environment are likely to be reliable. For bones protected from weathering before burial, and then incorporated in a stable, carbonate-rich environment, the filtered bone gelatin procedure used in this study is adequate to give reliable AMS ages. Possible reasons for discrepancies in bone gelatin AMS dates relative to marine shell, or charcoal dates from archaeological sites in dune deposits, are also discussed. (author). 70 refs., 7 figs., 2 tabs

  17. IBA analyses and lead concentration measurements of AMS-14C dated bones from two medieval sites in Italy

    International Nuclear Information System (INIS)

    AMS (accelerator mass spectrometry) radiocarbon dated human bone samples recovered in the deserted medieval village of Quattro Macine, Lecce, in Southern Italy, were analyzed by PIXE (particle induced X-ray emission) and PIGE (particle induced gamma ray emission). The optimization of the PIXE-PIGE experimental set-up in term of beam energy and detection geometry resulted in the possibility to obtain information about major, minor and trace elements of the samples. Unexpectedly, all the analyzed samples showed a Pb concentration higher than 50 ppm. Two possible explanations of the measured high Pb concentration are discussed in the paper: the pre-mortem intake associated with the use of Pb-rich glazed pottery and the post-mortem intake from soil as the result of diagenetic processes

  18. The necessity of sample quality assessment in 14C AMS dating: The case of Cova des Pas (Menorca - Spain)

    International Nuclear Information System (INIS)

    The Cova des Pas cave is a karstic cave in the cliffs of the Barranc (canyon) de Trebaluger. It is a small cave only 6.5 m deep, 4.5 m wide and 1.7 m high. Yet more than 70 burials, in foetal position, from the Early Iron Age were found in this small cave. The conservation of the archaeological remains was very unusual. Not only wood, ropes and other plant material was found, but also remains of body tissue, hair and leather. In spite of the remarkable preservation of the bodies and artefacts, the state of conservation of the bone material was very bad. The bones contained little and heavily deteriorated collagen and the organic plant material was very fragile. The special environmental conditions of the cave are the cause of these unusual preservation conditions. Although the cave is situated in a limestone cliff, the soil of the cave is very acid. Unexpectedly bad sample quality seemed to be the major drawback for AMS radiocarbon dating on hair, wood, ropes and bone collagen, as well as on bio-apatite.

  19. ESR and AMS-based 14C Dating of Mousterian Levels at Mujina Pećina, Dalmatia, Croatia

    NARCIS (Netherlands)

    Rink, W.J.; Karavanić, I.; Pettitt, P.B.; Plicht, J. van der; Smith, F.H.; Bartoll, J.; Karavanic, I.

    2002-01-01

    This paper presents the first chronometric dates for sediments that contain a Mousterian industry in Dalmatia (south Croatia). Electron spin resonance (ESR) dating was conducted on two teeth from the Mousterian level E1 at the site of Mujina Pećina. Additionally five bone and one charcoal sample fro

  20. 14C AMS dates on Rattus exulans bones from natural and archaeological contexts on Norfolk Island, south-west Pacific

    International Nuclear Information System (INIS)

    The Pacific rat (Rattus exulans) was transported throughout the western Pacific by migrant peoples in prehistory. Meredith et al (1985) reported a minimum date for the presence of Rattus exulans on Norfolk Island using dates on charcoal from an apparently enclosing layer (the upper part of their Unit C4) in Cemetery Bay. 8 refs., 3 tabs

  1. AMS 14C dating of deglacial events in the Irish Sea Basin and other sectors of the British Irish ice sheet

    Science.gov (United States)

    McCabe, A. M.; Clark, P. U.; Clark, J.

    2005-08-01

    Sedimentary sequences deposited by the decaying marine margin of the British-Irish Ice Sheet (BIIS) record isostatic depression and successive ice sheet retreat towards centres of ice dispersion. Radiocarbon dating by accelerator mass spectrometry (AMS) of in situ marine microfaunas that are commonly associated with these sequences constrain the timing of glacial and sea level fluctuations during the last deglaciation, enabling us to evaluate the dynamics of the BIIS and its response to North Atlantic climate change. Here we use our radiocarbon-dated stratigraphy to define six major glacial and sea level events since the Last Glacial Maximum. (1) Initial deglaciation may have occurred ⩾18.3 kyr 14C BP along the northwestern Irish coast, in agreement with a deglacial age of ˜22 36Cl kyr BP for southwestern Ireland. Ice retreated to inland centres and areas of transverse moraine began to form across the north Irish lowlands. (2) Channels cut into glaciomarine deglacial sediments along the western Irish Sea coast are graded to below present sea level, identifying a fall of relative sea level (RSL) in response to isostatic emergence of the coast. (3) Marine mud that rapidly infilled these channels records an abrupt rise in global sea level of 10-15 m ˜16.7 14C kyr BP that flooded the Irish Sea coast and may have triggered deglaciation of a marine-based margin in Donegal Bay. (4) Intertidal boulder pavements in Dundalk Bay indicate that RSL ˜15.0 14C kyr BP was similar to present. (5) A major readvance of all sectors of the BIIS occurred between 14 and 15 kyr 14C BP which overprinted subglacial transverse moraines and delivered a substantial sediment flux to tidewater ice sheet margins. This event, the Killard Point Stadial, indicates that the BIIS participated in Heinrich event 1. (6) Subsequent deposition of marine muds on drumlins 12.7 14C kyr BP indicates isostatic depression and attendant high RSL resulting from the Killard Point readvance. These events

  2. Holocene sea-level determination relative to the Australian continent: U/Th (TIMS) and 14C (AMS) dating of coral cores from the Abrolhos Islands

    Science.gov (United States)

    Eisenhauer, A.; Wasserburg, G. J.; Chen, J. H.; Bonani, G.; Collins, L. B.; Zhu, Z. R.; Wyrwoll, K. H.

    1993-02-01

    U/Th (TIMS) and 14C (AMS) measurements are presented from two coral cores from the Easter group of the Houtman Abrolhos Islands between 28°S and 29°S on the western continental margin of Australia. The U/Th measurements on the Morley core from Morley Island cover a depth interval from 0.2 m above present sea level to 24.4 m below present sea level and comprise eleven samples. The ages vary between 6320 ± 50 a, at 0.2 m above sea level, and 9809 ± 95 a, at 24.4 m below sea level (all errors are 2σ). The mean growth rate is 7.1 ± 0.9 m/ka. The 14C dates of selected Morley core corals show that the 14C ages are ˜ 1000 a younger than their corresponding U/Th ages, which agrees with previous results. The main purpose of our 14C measurements is to be able to compare them precisely with other coral cores where no U/Th measurements are available. The U/Th measurements of the Suomi core from Suomi Island cover a depth interval from 0.05 m to 14.2 m below present sea level and consist of four samples. The ages vary between 4671 ± 40 a, at 0.05 m below sea level, and 7102 ± 82 a, at 14.2 m below sea level, with a mean growth rate of 5.8 ± 0.2 m/ka. The growth history of both cores is explained by a simple model in which the growth rates of the Morley core can be interpreted as reflecting local rates of sea level rise, whereas the Suomi core is interpreted as reflecting lateral growth during the past ˜ 6000 a. Our results indicate that sea level relative to the western margins of the Australian continent was about 24 m lower than present at about 9800 a B.P. ( 14C gives a date of 8500 a B.P.). Sea level then rose and reached a highstand, slightly higher than the present position at about 6300 a B.P ( 14C date: 5500 a). This highstand declined but was still higher than present at 4600 a B.P. This is in agreement with previous observations along the Australian coastal margins and with observations from the Huon peninsula (Papua New Guinea). Our results are very

  3. AMS 14 C dating controlled records of monsoon and Indonesian throughflow variability from the eastern Indian Ocean of the past 32,000 years

    Science.gov (United States)

    Li, Z. Y.; Chen, M. T.; Shi, X.; Liu, S.; Wang, H.

    2015-12-01

    Zi-Ye Li a, Min-Te Chen b, Hou-Jie Wang a, Sheng-Fa Liu c, Xue-Fa Shi ca College of Marine Geosciences, Ocean University of China, Qingdao 266100, P.R. Chinab Institute of Applied Geosciences, National Taiwan Ocean University, Keelung, Taiwan 20224, ROCc First Institute of Oceanography, SOA, Qingdao 266100, P.R. China Indonesian throughflow (ITF) is one of the most important currents responsible for transporting heat and moisture from the western Pacific to the Indian Oceans. The ITF is also well-known as effectively in modulating the global climate change with the interactions among ENSO and Asian monsoons. Here we present an AMS 14C dating controlled sea surface temperature (SST) record from core SO184-10043 (07°18.57'S, 105°03.53'E), which was retrieved from 2171m water depth at a north-south depression located at the southeastern offshore area of Sumatera in the eastern Indian Ocean. Based on our high-resolution SST using Mg/Ca analyses based on planktonic foraminifera shells of Globigerinoides ruber and alkenone index, U k'37-SST, oxygen isotope stratigraphy, and AMC 14C age-controls, our records show that, during the past 32,000 years, the SSTs were decreased which imply weaker ITF during Marine Isotope Stage (MIS) 2 and 3. The weaker UTF may respond to strengthened northeast monsoon during the boreal winter. During 21 to 15ka, the southeast monsoon had been stronger and the northeast monsoon was relatively weaker. During 15 to 8ka, rapid sea level rising may allow the opening of the gateways in the Makassar Strait and Lombok Strait that may have further strengthened the ITF. During the early Holocene, the northeast and southeast monsoons seem to be both strengthened. We will discuss the implications of the hydrographic variability and their age uncertainties in this paper during the meeting.

  4. Dating human DNA with the 14C bomb peak

    International Nuclear Information System (INIS)

    In 1963 the limited nuclear test ban treaty stopped nuclear weapons testing in the atmosphere. By then the addition from bomb-produced 14C had doubled the 14C content of the atmosphere. Through the CO2 cycle this excess exchanged with the hydrosphere and biosphere leading to a rapidly decreasing 14C level in the atmosphere. Today we are almost back to the pre-nuclear level. As a consequence all people on Earth who lived during the second half of the 20th century were exposed to this rapidly changing 14C signal. A few years ago, a group at the Department of Cell and Molecular Biology of the Karolinska Institute in Stockholm started to use the 14C bomb peak signal in DNA to determine retrospectively the age of cells from various parts of the human body (brain, heart, fat). In a collaboration with this group, we have studied the age of olfactory bulb neurons in the human brain. For this investigation, 14C AMS measurements were developed at VERA for very small carbon samples in the range from 2 to 4 micrograms. In the presentation the general concept of 14C bomb peak dating of human DNA and several applications are discussed.

  5. The use of AMS 14C dating to explore issues of occupation and demise at the medieval city of Angkor, Cambodia

    Science.gov (United States)

    Penny, Dan; Hua, Quan; Pottier, Christophe; Fletcher, Roland; Barbetti, Mike

    2007-06-01

    Angkorian temples are characterised by one or more encircling moats that are excavated into the alluvial substrate. As a key part of the overall design of the temple, the moats are important symbolically and are presumed to be contemporaneous with the associated temple. They also represent important depositional basins for sediment and other materials and can therefore yield vertical profiles of sediment that has accumulated since the moat was originally excavated. Unconformities in these moat profiles can be dated absolutely using small-sample, high-precision AMS radiocarbon techniques. These unconformities are likely to represent periodic re-excavation or maintenance of the moat and therefore indicate the presence of large, presumably centrally organised workforces. In some instances, presumed anthropogenic unconformities occur centuries after Angkor was supposedly abandoned. In this way, radiocarbon dates themselves are being used as a proxy indicator of cultural activity and are being used to challenge the historiography of Angkor's famous demise.

  6. The use of AMS 14C dating to explore issues of occupation and demise at the medieval city of Angkor, Cambodia

    International Nuclear Information System (INIS)

    Angkorian temples are characterised by one or more encircling moats that are excavated into the alluvial substrate. As a key part of the overall design of the temple, the moats are important symbolically and are presumed to be contemporaneous with the associated temple. They also represent important depositional basins for sediment and other materials and can therefore yield vertical profiles of sediment that has accumulated since the moat was originally excavated. Unconformities in these moat profiles can be dated absolutely using small-sample, high-precision AMS radiocarbon techniques. These unconformities are likely to represent periodic re-excavation or maintenance of the moat and therefore indicate the presence of large, presumably centrally organised workforces. In some instances, presumed anthropogenic unconformities occur centuries after Angkor was supposedly abandoned. In this way, radiocarbon dates themselves are being used as a proxy indicator of cultural activity and are being used to challenge the historiography of Angkor's famous demise

  7. Using of the AMS - 14 C technique for dating of soil charcoals, from holocene period, in the amazon forest(Manaus-Brazil region)

    International Nuclear Information System (INIS)

    The Accelerator Mass Spectrometry (AMS) technique was used to determine the radiocarbon age of charcoal fragments of soil samples from the Amazon Region near Manaus. The radiocarbon ages are within the 130 - 2400 years range. The interpretation is that these results are evidences of important fire events that occurred mostly during the superior Holocene dry phase. These res had spread out more intensely at the high land areas than at shoals. In this paper there are descriptions of the processes of sample preparation and the procedures for the AMS analysis. (author)

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

    Institute of Scientific and Technical Information of China (English)

    CAI Yanjun; Warren Beck; PENG Zicheng; ZHANG Zhaofeng

    2005-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

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

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

    International Nuclear Information System (INIS)

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

  11. Application of AMS 14C measurements to criminal investigations

    International Nuclear Information System (INIS)

    14C variations of atmospheric CO2 as well as carbonaceous materials of human body, such as collagen fractions from teeth and bone, tissue, hair, nail, etc., of modern humans dead or alive, are influenced by 14C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of 14C concentration of tree rings and human tissue samples formed in this time ranges, we can establish a relation between their 14C concentrations and calendar year. By applying this relation to a sample whose 14C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the drugs that were used in some criminal cases can be possibly identified by the analysis of their carbon isotope ratios (13C/12C and 14C/12C). This method of age determination was applied to a forensic study; i.e., to two similar cases of murder. One of the two cases is for a dead body of a modern human who was killed in 1978 and buried under the floor of the house owned by the murderer. The body was excavated in 2004 according to the confession by the murderer. 14C abundances of several pieces of hair and one tooth (the third molar) from the body were measured with accelerator mass spectrometry (AMS), and compared with the annual change on concentrations of bomb-produced 14C. The time of death of the body was estimated to be at around 1977, and her age was from 30 to 37 years old at that time. These estimations were consistent with the real values that were revealed after the case was solved by the confession of the real murderer who gave himself up to the police. For the other case, 14C analysis was also consistent with the fact revealed by police investigations as well as by the confession of the real murderer.

  12. {sup 14} C dating by using mass spectrometry with particle accelerator; Datacao por {sup 14} C utilizando espectrometria de massa com acelerador de particulas

    Energy Technology Data Exchange (ETDEWEB)

    Santos, G.M.; Gomes, P.R.S. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Fisica]. E-mail: paulogom@if.uff.br; Yokoyama, Y. [Australian National Univ., Canberra (Australia). Research School of Earth Science; Tada, M.L. di; Cresswell, R.G.; Fifield, L.K. [Australian National Univ., Canberra (Australia). Dept. of Nuclear Physics

    1999-03-01

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

  13. Forensic applications of 14C bomb-pulse dating

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-08-01

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

  15. Forensic applications of 14C bomb-pulse dating

    Science.gov (United States)

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

    2004-08-01

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

  16. Effect of HF leaching on 14C dates of pottery

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2013-01-01

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

  18. Fine resolution AMS 14C chronology for Lunette-Lake sediment sequences, Lake Bolac, Victoria

    International Nuclear Information System (INIS)

    This study aims to provide a fine-resolution chronology for lake sediment records from Lakes Bolac and Turangmoroke, located within the drier part of the Western Plains, Victoria. These lakes are expected to be sensitive to subtle climate and vegetation variability and have long been recognised as archaeologically rich, bearing stone tools, hearth and other cultural materials dated to the late Pleistocene (Horton, 1984; former Victorian Aboriginal Survey, unpublished data). Fine-resolution chronological control has rarely been attempted in this sedimentary and (semi-arid) climatic context owing to the paucity of material available for conventional 14C dating. However, pollen and microscopic charcoal in the lake sediments at Bolac and Turangmoroke are suitable for AMS age determination with the most important sedimentary section well within the range of 14C making them ideal records for such a study. Recent dating results, which have substantially increased chronostratigraphic interpretation of concurrent palaeoecological and sedimentological work in progress, are presented

  19. Fine resolution AMS {sup 14}C chronology for Lunette-Lake sediment sequences, Lake Bolac, Victoria

    Energy Technology Data Exchange (ETDEWEB)

    Cook, E. [Monash University, Clayton, VIC (Australia). Centre for Palynology and Palaeoecology, Department of Geography and Environmental Science

    1998-12-31

    This study aims to provide a fine-resolution chronology for lake sediment records from Lakes Bolac and Turangmoroke, located within the drier part of the Western Plains, Victoria. These lakes are expected to be sensitive to subtle climate and vegetation variability and have long been recognised as archaeologically rich, bearing stone tools, hearth and other cultural materials dated to the late Pleistocene (Horton, 1984; former Victorian Aboriginal Survey, unpublished data). Fine-resolution chronological control has rarely been attempted in this sedimentary and (semi-arid) climatic context owing to the paucity of material available for conventional {sup 14}C dating. However, pollen and microscopic charcoal in the lake sediments at Bolac and Turangmoroke are suitable for AMS age determination with the most important sedimentary section well within the range of {sup 14}C making them ideal records for such a study. Recent dating results, which have substantially increased chronostratigraphic interpretation of concurrent palaeoecological and sedimentological work in progress, are presented

  20. The 14C-AMS Laboratory at IF-UFF

    International Nuclear Information System (INIS)

    Full text: In 2009 a radiocarbon sample preparation laboratory dedicated to Accelerator Mass Spectrometry was installed at the Physics Institute of the Fluminense Federal University. At the Radiocarbon Laboratory samples of several kinds of materials such as charcoal, sediments, wood and shells go through specific chemical treatment and conversion to carbon dioxide. Graphite reduction is performed in sealed Pyrex tubes, using Zinc, Titanium Hydrate, and iron catalyst within an inner tube. Samples have been successfully produced yielding fluffy homogeneous graphite leading to high and stable currents in the ion source. For sample measurement an accelerator system produced by the National Electrostatics Corporation (NEC), was installed in the Physics Institute. The machine, specially developed to carbon analysis, is the State of the Art in 14C - AMS studies and its acquisition represent a very important step for Brazil towards the development of science and technology regarding radiocarbon studies. The system includes an open air deck 250 kV single stage electrostatic accelerator with magnetic and electrostatic analyzers that enable isotope separation and detection. Radiocarbon concentrations are measured to 1 part in 1015 with precision of 0.3 The Nuclear Applied Physics group on Chronological Studies is now performing multidisciplinary research in collaboration with Brazilian and foreign groups from several fields of science such as Archaeology, Geophysics, Oceanography and Biology, in studies on the evolution of marine, terrestrial and Antarctic ecosystems. (author)

  1. Dating of groundwater with tritium and 14C

    International Nuclear Information System (INIS)

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

  2. Application of AMS 14C measurements to criminal investigations

    International Nuclear Information System (INIS)

    14C variations of atmospheric CO2 as well as carbonaceous fraction of living materials, such as collagen from tooth and bone, tissue, skin, hair, nail, etc., of modern humans are influenced by 14C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of 14C concentration of tree rings and human body samples formed in this time intervals, we can establish a relationship of their 14C concentrations with calendar year. By applying this relation to a sample whose 14C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the chemicals that were used in some criminal cases can be possibly identified, by their carbon isotope ratios (13C/12C and 14C/12C). This method of age determination has been applied to a forensic study, i.e., two criminal cases of murder. For each case, by comparing the measured 14C abundances of several pieces of hair and one tooth (the third molar) from the body with the annual change on concentrations of bomb-produced 14C, the time of death of the body and the age of the victim were estimated. The estimated values were consistent with the real ones that were revealed by the confession of the real murderers. (author)

  3. Carbonates in leaching reactions in context of 14C dating

    Science.gov (United States)

    Michalska, Danuta; Czernik, Justyna

    2015-10-01

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

  4. Direct 14C dating of megalithic paints from NW Iberia

    Directory of Open Access Journals (Sweden)

    Carrera Ramírez, Fernando

    2002-06-01

    Full Text Available In this paper we present 5 AMS dates obtained from the paintings found on the uprights of 4 Galician megalithic graves. The results have shown that this art belongs roughly to the first half of the 4th millennium BC and pose the question of the contemporaneity of the building of the chambers and the execution of the paintings and also the occurrence of more than one episode of decoration in them.

    En este trabajo damos a conocer cinco dataciones radiocarbónicas AMS obtenidas a partir de muestras de pintura de cuatro monumentos megalíticos gallegos. Los resultados obtenidos confirman la utilidad de este tipo de análisis a la hora de trazar la cronología de estas manifestaciones artísticas (en torno a la primera mitad del IV milenio AC y plantean además nuevas cuestiones acerca de la simultaneidad entre la pintura y la construcción de las cámaras, así como la existencia de dos o más episodios pictóricos.

  5. Changes in solar activity and Holocene climatic shifts derived from 14C wiggle-match dated peat deposits

    NARCIS (Netherlands)

    Mauquoy, Dmitri; Geel, Bas van; Blaauw, Maarten; Speranza, Alessandra; Plicht, Johannes van der

    2004-01-01

    Closely spaced sequences of accelerator mass spectrometer (AMS) 14C dates of peat deposits display century-scale wiggles which can be fitted to the radiocarbon calibration curve. By wiggle-matching such sequences, high-precision calendar age chronologies can be generated which show that changes in m

  6. AMS 14C age of the earliest pottery from the Russian Far East: 1996-2002 results

    International Nuclear Information System (INIS)

    The new results of AMS 14C dating of the earliest pottery from the Russian Far East, Osipovka, Gromatukha and Novopetrovka cultural complexes (Amur River basin), are presented. Pottery temper (represented by sedge grass) was chosen for dating; pottery-associated charcoal was also dated. The earliest pottery from the Amur River basin nowadays may be dated to ca. 13 000 BP (ca. 16 000 cal BP), and this is one of the oldest potteries in East Asia, and in Old World in general

  7. Biokinetic and dosimetric investigations of 14C-labeled substances in man using AMS

    International Nuclear Information System (INIS)

    Up to now, radiation dose estimates from radiopharmaceuticals, labeled with pure β-emitting radionuclides, e.g., 14C or 3H have been very uncertain. Using accelerator mass spectrometry (AMS) we have derived new and improved data for 14C-triolein and 14C-urea and are currently running a program related to the biokinetics and dosimetry of 14C-glycocholic acid and 14C-xylose. The results of our investigations have made it possible to widen the indications for the clinical use of the 14C-urea test for Helicobacter pylori infection in children. The use of ultra-low activities, which is possible with AMS (down to 1/1000 of that used for liquid scintillation counting), has opened the possibility for metabolic investigations on children as well as on other sensitive patient groups like new-borns, and pregnant or breast-feeding women. Using the full potential of AMS, new 14C-labeled drugs could be tested on humans at a much earlier stage than today, avoiding uncertain extrapolations from animal models

  8. New batch system for 14C accelerator mass spectrometry (AMS): Graphite target preparation at the INGEIS Laboratories, Argentina

    International Nuclear Information System (INIS)

    At present a new batch system for the production of graphite from CO2 is functioning at the INGEIS 14C laboratory. The main goal of the system is to do specific targets by catalytic reduction for a new AMS system which is being installed in the building of the Autoridad Regulatoria Nuclear (Beninson et al., 2000). There are two methods for determining very low concentrations of radio nuclides: measuring the radiation emitted by their radioactive decay or measuring the particular atoms themselves. The atom counting method is more efficient in the case of long-lived radio nuclides, i.e. radionuclides with half-lives much longer than a given measuring time (v.gr.14C, βemitter, T1/2 = 5730 years) and for samples with small radioisotope abundance. In the case of age measurement, the majority of dates have been determined by radioactive decay counting techniques. For 14C low activity samples, specially those older, larger samples, 1 to 10 g of elemental carbon are required to achieve good counting statistic. Due to their low activity, samples older than 50.000 years may not be reliably dated by β counting. An example illustrates differences between the counting method and the AMS: a 2 cm human hair contains about one mg of carbon in the form of a protein compound, keratin. One mg of carbon has 5 x 1019 stable 12C atoms. Like global atmospheric ratio 14C /12C = is ca 1,2 x 1012, contains also 6 x 107 atoms of 14C and only one of these atoms decays in one hour. Conversely, this one mg used up in the ion source of an AMS can collect 6 x 10514C atoms. This examples clearly shows the enormous gain in detection efficiency of atom collection of AMS over decay counting method of measurement (au)

  9. AMS studies of the long-term turnover of 14C-labelled fat in man

    International Nuclear Information System (INIS)

    To estimate the biokinetics of 14C-labelled fatty acids and the associated radiation absorbed dose to man, long-term retention of 14C from oral intake of glycerol tri[1-14C]oleate (triolein) has been studied using accelerator mass spectrometry (AMS). As a complement to earlier reported data for three individuals, we present here results for one person from measurements up to 4.6 yr after administration, now also including 14C-levels in fat, muscle and bone. In this subject, a total of 44% of the administered activity was recovered in the exhaled air. Fasting increased the exhalation of 14C. The 'excess' 14CO2 due to fasting had a half-life of about 400 d. AMS measurements on fat, muscle and bone biopsies taken from the same subject 4.5 yr after ingestion indicated that a small fraction of the administered activity was still present in fat. Also, bone tissue had a higher 14C specific activity than the current environmental level. No significantly increased level was found in the muscle sample

  10. The derivation of 14C dating standards for fresh-water shell-fish

    International Nuclear Information System (INIS)

    14C analyses of hyridella shell-fish from four different localities were used to determine suitable 14C dating standards for these shell-fish. For each locality the dating standard deduced was considerably less than the 0.95 NBS oxalic acid standard, and notably the estimated standard for a group of Lake Taupo shell-fish was estimated to be only 55% to 62% of the NBS oxalic acid standard level. Variability of hyridella 14C standards with locality and time may limit the confidence that can be placed in radiocarbon dates from hyridella

  11. AMS 14C performance test of a new automated bone preparation system

    International Nuclear Information System (INIS)

    Complete text of publication follows. Bone is one of the most complex sample materials for radiocarbon dating. After burial, its physical state and chemical composition can be affected by many environmental processes. In case of our new AMS bone preparation technique, after ultrasonication in distilled water, drying, surface cleaning and grinding, the sample is sieved to get the appropriate sized sample fraction (0.5 - 1 mm) out of which 500 - 1000 mg is measured, depending on the state of the bone. We have developed our own continuous flow bone sample preparation equipment. In this unit OMNIFITTM columns are used as flow cells to construct our own automatic ABA (acid-base-acid) cleaning system. From 3 types of reagent, each one is injected via a 4 way valve and inert plastic tubing to an IsmatechTM IPC 12 channel peristaltic pump to ensure a constant flow rate. Reagents are selectively pumped to the reaction cells containing the powdered bone samples, with a sequence of 0.5 M HCl and 0.1 M NaOH solution, interspersed with flushing with distilled water. During the sixteen-hour-long process, reagents follow a well-defined sequence that is controlled by a computer program and a special electronic driver device. The cleaned sample is inserted into a test tube containing 5 ml, pH 3 aqueous solutions, and it is placed into a heating block at 75 deg C for 24 hours. Dissolved collagen is filtered via a 45 μm glass fibre filter (WhatmanTM AUTOVIAL 5) into a clean vial, and after freezing, it gets freeze-dried, a process which takes at least a day. To investigate the sample-preparation reproducibility and possible extra contamination effect by an optional ultra-filtration process a known-age bone sample, previously dated by an independent method (GPC at HEKAL), was prepared several times using the new AMS preparation line for 14C analyses. The results obtained (Figure 1.) showed very good reproducibility and excellent agreement with the classical GPC measured 14C age in

  12. Mass Balance Model, A study of contamination effects in AMS 14C sample analysis

    NARCIS (Netherlands)

    Prokopiou, Markella

    2010-01-01

    In this training thesis a background correction analysis, also known as mass balance model, was implemented to study the contamination effects in AMS 14C sample processing. A variety of backgrounds and standards with sizes ranging from 50 μg C to 1500 μg

  13. AMS-dating of Late Pleistocene and Holocene syngenetic ice-wedges

    International Nuclear Information System (INIS)

    We discuss the 14C dating (both conventional and AMS) of Siberian permafrost sediments and ice-wedge ice. Direct dating of Late Pleistocene and Holocene syngenetic ice-wedges was done on organic material included in the ice. The time of ice formation (in 14C years) is 21,000-14,000 BP for Seyaha, and 7100 BP for Shchuch'ya. The AMS dates show that the ice-wedges stratification is normal, i.e., the older ice is located below the younger. The 14C dates yield for the first time a timescale (in 14C years) for paleoclimatic indicators (oxygen and hydrogen isotope ratios from the ice)

  14. The remarkable metrological history of 14C dating: from ancient Egyptian artifacts to particles of soot and grains of pollen

    International Nuclear Information System (INIS)

    enhancement by some six orders of magnitude was the result, where 14C atoms are measured directly by accelerator mass spectrometry (AMS), in place of beta particle (decay) counting. (Apart from differences in detection efficiency, the relative sensitivity derives from the first order relationship between the nuclear disintegration rate and the ratio of the 14C atom concentration to the mean life.) The resultant ability to date ca. 100 μg of carbon has fostered major developments in 'molecular dating' (e.g., via GC/AMS) that have had a profound impact on artifact dating accuracy, and provided new insights into the sources, transport, and age of individual carbonaceous species in the environment. The talk concluded with some current applications of the advanced 14C metrology, such as the dating of individual amino acids in prehistoric bones, and efforts to extract the recent history of fossil and biomass burning from soot particles trapped in polar and mid-latitude ice cores. (author)

  15. Future needs and requirements for AMS 14C standards and reference materials

    International Nuclear Information System (INIS)

    14C measurement uses a number of standards and reference materials with different properties. Historically the absolute calibration of 14C measurement was tied to 1890 wood, through the 'primary' standard of NBS-OxI (produced by the National Bureau of Standards, now NIST - National Institute of Standards and technology) subsequently replaced by NBS-OxII. These are both internationally calibrated and certified materials, whose 14C activities are known absolutely. A second tier of materials, often called secondary standards or reference materials, and including internationally recognised materials such as ANU-sucrose (now also IAEA-C6), Chinese - sucrose and the IAEA C1-C6 series, augmented by additional oxalic acid samples are also used routinely. The activity of these materials has been estimated from large numbers of measurements made by many laboratories. Recently, further natural materials from the Third and Fourth International Radiocarbon Inter-comparisons (TIRI and FIRI) have been added to this list. The activities of these standards and reference materials span both the applied 14C age range and the chemical composition range of typical samples, but this is not achieved uniformly and there is a continuing need for reference materials for laboratory quality control and measurement-traceability purposes. In this paper, we review the development of 14C standards and reference materials and consider the future requirements for such materials within the 14C AMS community

  16. 14C AMS measurements of tree leaf samples to monitor air pollution induced by city traffic

    International Nuclear Information System (INIS)

    In the past, many radiocarbon measurement have been made for environmental studies such as source apportionment of air-borne particulates, and studies of the anthropogenic effects of nuclear power plants. In this presentation we report our accelerator mass spectrometry (AMS) measurements of radiocarbon on tree leaf samples to investigate the impact of city traffic on our living-environment. The fossil-burning vehicles emit carbon dioxide (CO2) free of 14C content and, when mixed with the clean air CO2, lower 14C ratio compared to the normal reservoir value. This so-called Suess effect can be incorporated to monitor air quality in our living environments, since metabolic processes maintain the 14C content of living organism in equilibrium with atmospheric 14C. In other words, dead CO2 is admixed to the normal atmospheric CO2 and then photo-synthetically assimilated by the plants. Two kinds of tree leaf samples; pine tree needles and Ginkgo tree leaves were collected during a one-week period in the summer 1996 at five different locations with various traffic conditions in the region, within a 10-km diameter circle, south of the River Han, Seoul. The AMS targets were made by a simple sample-making procedure. The leaves have been pretreated by a standard acid-alkali treatment and then charred in a vacuum evaporator by applying ca. 800 deg C heat. The charred samples were mixed with Ag powder and pressed into the Al target holder for the AMS measurement.The AMS measurements were made using the accelerator mass spectrometry facilities of the Leibniz-Labor at the Christian-Albrecht University, Kiel,Germany. The observed Δ14C values, which ranged from 60TM to 158TM, have a good correlation with the traffic conditions in the places where the sampling took place and show a remarkable capability of 14C AMS measurements to monitor our fossil burning environment. The volume ratios of clean air to air from fossil-burn origin in the environmental CO2 reached to a level of 8

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

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

  18. Applications of 14C-AMS on archaeology, climate, environment, geology, oceanography and biology

    International Nuclear Information System (INIS)

    The first experiment discusses the chronology of prehistoric settlements of the central-south Brazilian coast. In the southern Brazilian coast there is a high density of these shellmounds, dated in general between 6,000 and 2,000 BP. A charcoal sample from a coastal shellmound of Rio de Janeiro State was dated by 14C-AMS to 7,860±80 years BP. This is an unexpected result that pulls back by some two thousand years the antiquity consensually accepted for the settlement of that region. We performed an experiment concerning the isotopic signature of the local waters of an important Brazilian coastal upwelling, located in Arraial do Cabo, R.J., with applications in the fields of Oceanography and Marine Ecology. We assess the contribution of the wind-driven coastal upwelling of Arraial do Cabo to the local biological production. The variation of the carbon isotopic compositions was investigated in a population of a seaweed. Upwelling events were simulated in the laboratory, in order to study three regimes: total upwelling (SACW), partial upwelling (mixed water) and no-upwelling (TW). Water samples were collected at 70 m depth (SACW) and at 10 m (TW). The seaweed was cultivated during seven days, in controlled conditions, into the three mentioned types of water. The results of 14C-AMS measurements in the seaweed tissue show a clear indication of difference in the isotopic signature of the water sources, allowing to infer the differences of the water sources. We believe that the present results contribute to opening new perspectives for the use of 14C as a tracer of the biological production in upwelling areas all over the world. The next reported experiment is on climate at the Amazon region. An increase in the Hg flux is a strong indicator of disturbance in a forest ecosystem related to abrupt changes in the water balance, and its changes reflect changes in the ocean and average regional temperatures. In regions where the geological background of mercury is negligible

  19. 14C dating of bone using (gamma) Carboxyglutamic Acid and Carboxyglycine (Aminomalonate)

    Energy Technology Data Exchange (ETDEWEB)

    Southon, J R; Burky, R T; Kirner, D L; Taylor, R E; Hare, P E

    1999-04-27

    Radiocarbon determinations have been obtained on {gamma}-carboxyglutamic acid [Gla] and {alpha}-carboxyglycine (aminomalonate) [Am] as well as acid- and base-hydrolyzed total amino acids isolated from a series of fossil bones. As far as they are aware, Am has not been reported previously in fossil bone and neither Gla nor Am {sup 14}C values have been measured previously. Interest in Gla, an amino acid found in the non-collagen proteins osteocalcin and matrix Gla-protein (MGP), proceeds from the suggestion that it may be preferentially retained and more resistant to diagenetic contamination affecting {sup 14}C values in bones exhibiting low and trace amounts of collagen. The data do not support these suggestions. The suite of bones examined showed a general tendency for total amino acid and Gla concentrations to decrease in concert. Even for bones retaining significant amounts of collagen, Gla (and Am extracts) can yield {sup 14}C values discordant with their expected age and with {sup 14}C values obtained on total amino-acid fractions isolated from the same bone sample.

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

    International Nuclear Information System (INIS)

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

  1. AMS 14C measurement of small volume oceanic water samples: Experimental procedure and comparison with low-level counting technique

    International Nuclear Information System (INIS)

    The technique for small volume oceanic AMS 14C measurement is described. The procedure includes sampling, CO2 extraction from the water samples, target preparation and measurement at the ETH/SIN AMS facility. AMS 14C data from a station in the southern Weddell Sea with an accuracy of ±5per mille are presented. The data are in good agreement with large volume 14C measurements done by conventional low-level counting techniques with an accuracy of ±2per mille. (orig.)

  2. Methods for high precision 14C AMS measurement of atmospheric CO2 at LLNL

    Energy Technology Data Exchange (ETDEWEB)

    Graven, H D; Guilderson, T P; Keeling, R F

    2006-10-18

    Development of {sup 14}C analysis with precision better than 2{per_thousand} has the potential to expand the utility of {sup 14}CO{sub 2} measurements for carbon cycle investigations as atmospheric gradients currently approach traditional measurement precision of 2-5{per_thousand}. The AMS facility at the Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, produces high and stable beam currents that enable efficient acquisition times for large numbers of {sup 14}C counts. One million {sup 14}C atoms can be detected in approximately 25 minutes, suggesting that near 1{per_thousand} counting precision is economically feasible at LLNL. The overall uncertainty in measured values is ultimately determined by the variation between measured ratios in several sputtering periods of the same sample and by the reproducibility of replicate samples. Experiments on the collection of one million counts on replicate samples of CO{sub 2} extracted from a whole air cylinder show a standard deviation of 1.7{per_thousand} in 36 samples measured over several wheels. This precision may be limited by the reproducibility of Oxalic Acid I standard samples, which is considerably poorer. We outline the procedures for high-precision sample handling and analysis that have enabled reproducibility in the cylinder extraction samples at the <2{per_thousand} level and describe future directions to continue increasing measurement precision at LLNL.

  3. {sup 14}C dating of the Early to Late Bronze Age stratigraphic sequence of Aegina Kolonna, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Wild, E.M., E-mail: Eva.Maria.Wild@univie.ac.a [VERA Laboratory, Faculty of Physics - Isotope Research, University of Vienna, Waehringer Strasse 17, A-1090 Wien (Austria); Gauss, W. [Austrian Archaeological Institute at Athens, Leof. Alexandras 26, Gr10683 Athens (Greece); Forstenpointner, G. [University of Veterinary Medicine Vienna, Dept. of Pathobiology, Institute of Anatomy, Unit on Archaeozoology and Comparative Morphology, Veterinaerplatz 1, A-1210 Vienna (Austria); Lindblom, M. [Dept. of Archaeology and Ancient History Uppsala, University Box 626, SE-751 26 Uppsala (Sweden); Smetana, R. [Altertumswissenschaften, University of Salzburg, Residenzplatz 1/I, A-5020 Salzburg (Austria); Steier, P. [VERA Laboratory, Faculty of Physics - Isotope Research, University of Vienna, Waehringer Strasse 17, A-1090 Wien (Austria); Thanheiser, U. [Vienna Institute for Archaeological Science (VIAS), Althanstrasse 14, A-1090 Vienna (Austria); Weninger, F. [VERA Laboratory, Faculty of Physics - Isotope Research, University of Vienna, Waehringer Strasse 17, A-1090 Wien (Austria)

    2010-04-15

    Aegina Kolonna, located in the center of the Saronic Gulf in the Aegean Mediterranean (Greece), is one of the major archaeological sites of the Aegean Bronze Age with a continuous stratigraphic settlement sequence from the Late Neolithic to the Late Bronze Age. Due to its position next to the maritime cross roads between central mainland Greece, the northeast Peloponnese, the Cyclades and Crete, the island played an important role in the trade between these regions. In the course of new excavations, which focused on the exploration of the Early, Middle and Late Bronze Age at Kolonna, several short lived samples from different settlement phases have been {sup 14}C-dated with the AMS method at the VERA laboratory. Bayesian sequencing of the {sup 14}C data according to the stratigraphic position of the samples in the profile was performed to enable estimates of the transition time between the cultural phases. The Aegina Kolonna {sup 14}C sequence is one of the longest existing so far for the Aegean Bronze Age, and therefore of major importance for the absolute Bronze Age chronology in this region. Preliminary results indicate that the Middle Helladic period seems to have started earlier and lasted longer than traditionally assumed. Further, at the present stage of our investigation we can give also a very tentative time frame for the Santorini volcanic eruption which seems to be in agreement with the science derived VDL date.

  4. From 14C/12C measurements towards radiocarbon dating of ice

    International Nuclear Information System (INIS)

    A dry extraction method of CO2 included in glacier ice adds a contamination equivalent to 1.8 μg modern carbon for a 35 μg C sample. This enables radiocarbon dating by accelerator mass spectrometry of 35 μg C samples to about 25 000 BP. Measured 14C/12C ratios are presented for a part of the Vostok ice core, and for some surface samples; high 14C/12C values ranging between 65 and 105 pm C indicate in-situ 14C production during the ablation. The reproducibility of radiocarbon dating of ice is demonstrated by results for some parts of the Caroline core, yielding an age versus depth profile, in which the age does not simply increases with depth. The results indicate that the accuracy of radiocarbon dating of ice is not limited by the statistical error arising in the accelerator measurements, but by the uncertainty in the contamination background of the samples and by the in-situ production of 14C. 12 refs, 4 figs, 2 tabs

  5. Free flow electrophoresis separation and AMS quantitation of {sup 14}C-naphthalene-protein adducts

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, Bruce A., E-mail: bbuchholz@llnl.go [Center for AMS, LLNL, 7000 East Avenue, Livermore, CA 94551 (United States); Haack, Kurt W.; Sporty, Jennifer L. [Center for AMS, LLNL, 7000 East Avenue, Livermore, CA 94551 (United States); Buckpitt, Alan R.; Morin, Dexter [Department of Molecular Biosciences, School of Veterinary Medicine, UC Davis, Davis, CA 95616 (United States)

    2010-04-15

    Naphthalene is a volatile aromatic hydrocarbon to which humans are exposed from a variety of sources including mobile air sources and cigarette smoke. Naphthalene produces dose-(concentration)dependent injury to airway epithelial cells of murine lung which is observed at concentrations well below the current occupational exposure standard. Toxicity is dependent upon the cytochrome P450 mediated metabolic activation of the parent substrate to unstable metabolites which become bound covalently to tissue proteins. Nearly 70 proteins have been identified as forming adducts with reactive naphthalene metabolites using in vitro systems but very little work has been conducted in vivo because reasonably large amounts (100 muCi) of {sup 14}C labeled parent compound must be administered to generate detectable adduct levels on storage phosphor screens following separation of labeled proteins by 2D gel electrophoresis. The work described here was done to provide proof of concept that protein separation by free flow electrophoresis followed by AMS detection of protein fractions containing protein bound reactive metabolites would provide adducted protein profiles in animals dosed with trace quantities of labeled naphthalene. Mice were administered 200 mg/kg naphthalene intraperitoneally at a calculated specific activity of 2 DPM/nmol (1 pCi/nmol) and respiratory epithelial tissue was obtained by lysis lavage 4 h post injection. Free flow electrophoresis (FFE) separates proteins in the liquid phase over a large pH range (2.5-11.5) using low molecular weight acids and bases to modify the pH. The apparatus separates fractions into standard 96-well plates that can be used in other protein analysis techniques. The buffers of the fractions have very high carbon content, however, and need to be dialyzed to yield buffers compatible with {sup 14}C-AMS. We describe the processing techniques required to couple FFE to AMS for quantitation of protein adducts.

  6. The impact of new 14C dating on the European Neanderthal versus modern human discussion

    International Nuclear Information System (INIS)

    Full text: One of the most interesting time periods in human evolution is the transition period from Neanderthals to modern humans. The fate of the Neanderthals and the mode of the emergence of modern humans in Europe is still unresolved. It was speculated by some investigators that the Neanderthals could have been pushed to the margins of the continent by the early modern humans. Others argue that Neanderthals and modern humans may have co-existed over a considerable long time period in the same regions and even may have mixed with each other. Direct 14C dating of the rare and valuable human remains with accelerator mass spectrometry in combination with anthropological investigations and DNA-analysis offers a tool to shed light on this debate. The VERA laboratory contributed to this question by the successful direct 14C dating of the Mladec fossils - remains of early upper palaeolithic men - found in Moravia (Czech Republic) at the end of the 19th century and stored since then in the Museum of Natural History in Vienna. The determined 14C age of ∼ 31 ka BP (non-calibrated) indicates that the Mladec finds comprise one of the oldest substantial assemblage of human remains in Central Europe and play an important role in the Neanderthal / modern human discussion. It should be noted that the 14C age could correspond to an absolute age of several thousand years older. Unfortunately a reliable calibration of this age range is currently not possible. (author)

  7. OSL versus 14C dating of sandy pedosediments as paleo-ecological archives in cultural landscapes

    Science.gov (United States)

    van Mourik, J. M.

    2009-04-01

    Late glacial aeolian coversand dominates the surface geology of an extensive area in Northwest Europe. During prehistoric and early historic time, forest grazing, wood cutting and shifting cultivation gradually transformed natural forest into heath land. Subsequently the use of the heath for the production of organic manure during the period of plaggen agriculture (from early Middle Ages to the invention of chemical fertilizers around 1900 AD) resulted in the comeback of active sand drifting. Locally the coversand landscape transformed into a driftsand landscape with characteristic new landforms and soils. Important parts of soil archives in these cultural landscapes are fimic covers, records of a long period of agricultural history and polycyclic driftsand deposits, records of alternating instable and stable phases in landscape development. Based on pollen analysis of fimic covers and buried humic soil horizons in polycyclic driftsand sequences, a lot of paleoecological information is available to reconstruct the development of soils and landforms in cultural landscapes, but we need a correct chronological framework to correlate information of various sources and sites. Traditionally 14C dating was applied on humic horizons of buried soils and a 14C based chronological framework was designed to estimate the accumulation rate of fimic covers and to date stable and instable periods in polycyclic driftsand profiles. However, 14C dates of extracted SOM (soil organic matter) are not always reliable. Firstly, in studies of fimic antrosols arose disagreement between paleoecological and historical interpretators of the evolution of these antrosols. The results of soil micromorphology and 14C dating, applied on separated SOM fractions (humine, humic acids and fulvic acids) showed that SOM, present in fimic horizons, consists of a complex mix of compounds of different ages and sources. Secondly, 14C dates of buried humic soil horizons are not always reliable. In thin

  8. From 14C/12C measurements towards radiocarbon dating of ice

    NARCIS (Netherlands)

    Oerlemans, J.; Wal, R.S.W. van de; Roijen, J.J. van; Raynaud, D.; Borg, K. van der; Jong, A.F.M. de; Lipenkov, V.; Huybrechts, P.

    1994-01-01

    A dry extraction method of CO2 included in glacier ice adds a contamination equivalent to 1.8 μg modern carbon for a 35 μg C sample. This enables radiocarbon dating by accelerator mass spectrometry of 35 μg C samples to about 25 000 BP. Measured 14C/12C ratios are presented for a part of the Vostok

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Santos, G. M.; Mazon, M.; Southon, J. R.; Rifai, S.; Moore, R.

    2007-06-01

    We present an evaluation of different brands of cobalt and iron powders used to catalyze CO2 reduction for 14C-AMS graphite targets at the KCCAMS/University of California, Irvine. The optimal catalyst is characterized by rapid graphitization, homogeneity and lack of sintering of the catalyst/carbon mixture, and contains minimal amounts of both "modern" and "dead" carbon. Fifteen catalyst powders were evaluated using these criteria. The results of this study indicate three good "catalyst-candidates" with backgrounds on processed coal (Argonne Premium coal POC#3) samples around 60 ka BP and modern and dead carbon contamination of ⩽0.2 μgC for 4-5 mg of catalyst.

  11. Online coupling of pure O2 thermo-optical methods - 14C AMS for source apportionment of carbonaceous aerosols

    Science.gov (United States)

    Agrios, Konstantinos; Salazar, Gary; Zhang, Yan-Lin; Uglietti, Chiara; Battaglia, Michael; Luginbühl, Marc; Ciobanu, Viorela Gabriela; Vonwiller, Matthias; Szidat, Sönke

    2015-10-01

    This paper reports on novel separation methods developed for the direct determination of 14C in organic carbon (OC) and elemental carbon (EC), two sub-fractions of total carbon (TC) of atmospheric air particulate matter. Until recently, separation of OC and EC has been performed off-line by manual and time-consuming techniques that relied on the collection of massive CO2 fractions. We present here two on-line hyphenated techniques between a Sunset OC/EC analyzer and a MICADAS (MIni radioCArbon DAting System) accelerator mass spectrometer (AMS) equipped with a gas ion source. The first implementation facilitates the direct measurement in the low sample size range (<10 μg C) with high throughput on a routine basis, while the second explores the potential for a continuous-flow real-time CO2 gas feed into the ion source. The performance achieved with reference materials and real atmospheric samples will be discussed to draw conclusions on the improvement offered in the field of 14C aerosol source apportionment.

  12. AMS dating of early shellmounds of the Southeastern Brazilian coast

    Energy Technology Data Exchange (ETDEWEB)

    Lima, T. A. [Universidade Federal, Rio de Janeiro (UFRJ), RJ (Brazil). Museu Nacional. Dept. de Antropologia; Macario, K.D.; Anjos, R.M.; Gomes, P.R.S. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica; Coimbra, M.M. [Universidade Estadual de Londrina, PR (Brazil). Dept. de Fisica; Elmore, D. [Purdue Univ., IN (United States). Purdue Rare Isotopes Measurement Lab.

    2003-06-01

    This paper discusses the chronology of prehistoric settlements of the central-south Brazilian coast. A charcoal sample from a coastal shell mound of Rio de Janeiro State was dated by {sup 14} C-AMS to 7, 860+- 80 years B P as part of an interdisciplinary project between physicists and archaeologists. This is an unexpected result that reinforces two similar previous early dates for the same region, which were questioned by Brazilian archaeologists because they implied in pulling back by some two thousand years the antiquity consensually accepted for the settlement of that region. (author)

  13. AMS dating of early shellmounds of the Southeastern Brazilian coast

    International Nuclear Information System (INIS)

    This paper discusses the chronology of prehistoric settlements of the central-south Brazilian coast. A charcoal sample from a coastal shell mound of Rio de Janeiro State was dated by 14 C-AMS to 7, 860+- 80 years B P as part of an interdisciplinary project between physicists and archaeologists. This is an unexpected result that reinforces two similar previous early dates for the same region, which were questioned by Brazilian archaeologists because they implied in pulling back by some two thousand years the antiquity consensually accepted for the settlement of that region. (author)

  14. The timing of ostrich existence in Central Asia: AMS {sup 14}C age of eggshells from Mongolia and southern Siberia (a pilot study)

    Energy Technology Data Exchange (ETDEWEB)

    Kurochkin, Evgeny N. [Paleontological Institute, Russian Academy of Sciences, Profsouyznaya St. 123, Moscow 117647 (Russian Federation); Kuzmin, Yaroslav V., E-mail: kuzmin@fulbrightmail.or [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Koptuyg Avenue 3, Novosibirsk 630090 (Russian Federation); Antoshchenko-Olenev, Igor V. [S. Razin St. 5, Apt. 97, Kaluga 248012 (Russian Federation); Zabelin, Vladimir I. [Tuva Institute of Complex Studies of the Natural Resources, Siberian Branch of the Russian Academy of Sciences, Internatsionalnaya St. 17, Kyzyl 667007 (Russian Federation); Krivonogov, Sergey K. [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Koptuyg Avenue 3, Novosibirsk 630090 (Russian Federation); Nohrina, Tatiana I. [Institute of Archaeology and Ethnography, Siberian Branch of the Russian Academy of Sciences, Lavrentiev Avenue 17, Novosibirsk 630090 (Russian Federation); Lbova, Ludmila V. [Institute of Archaeology and Ethnography, Siberian Branch of the Russian Academy of Sciences, Lavrentiev Avenue 17, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogov St. 2, Novosibirsk 630090 (Russian Federation); Burr, G.S.; Cruz, Richard J. [Arizona AMS Laboratory, University of Arizona, Tucson, AZ 85721-0081 (United States)

    2010-04-15

    The presence of Asiatic ostrich in Central Asia in the later Cenozoic time is well-documented; nevertheless, a few direct age determinations existed until recently. We performed AMS {sup 14}C dating of ostrich eggshells found in Mongolia, Transbaikal, and Tuva. It shows that ostriches existed throughout the second part of Late Pleistocene, until the Late Glacial time (ca. 13,000-10,100 BP). It seems that Asiatic ostrich went extinct in Central Asia just before or even in the Holocene.

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

    Science.gov (United States)

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

    2016-03-01

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

  16. Development of the correction method of 14C groundwater dating. Evaluating the groundwater evolution and dating at the Rokkasho site

    International Nuclear Information System (INIS)

    To estimate the 14C groundwater age, groundwater evolution of dissolved inorganic carbon (DIC) needs to be investigated at a site. Groundwater evolution depends on the geochemical setting at a site. This paper proposed a correction method of 14C groundwater dating by evaluating the DIC groundwater evolution at the site of low level radioactive waste disposal in Rokkasho, Aomori prefecture, Japan. The δ13C of DICs in the shallow part of the Rokkasho site (shallower than ∼-100m elevation) showed inhomogeneous values. From the rock core chemical analysis, no inorganic carbon exited and concentrations of DIC were unchanged with depths in the shallow part. It indicates that carbonate mineral has no effect on δ13C values in the shallow part but recharging system affected on the δ13C of DIC. It is expected that both of open system and closed system or partially open and closed system recharging were taken place in shallower depth of the site. On the other hand, in the deep of the site (deeper than approx. = -100m elevation), there are shell fossils in aquifer consisting rocks. The shell fossils are dissolved based on the Na-(Ca, Mg) ion exchange reaction. It causes higher δ13C and lower 14C in the groundwater DIC at the deep part. The result of mass balance calculation of DIC concentrations and δ13C of DIC showed that DIC concentrations and δ13C was affected by some sort of reaction other than shell fossil dissolution in the deep part in the site. Correction of 14C was conducted by the IAEA equation. The corrected 14C groundwater age in this study shows good correlation with the result of other dating study derived by hydrological flow analysis compare to uncorrected age. (author)

  17. 14C dating with the bomb peak: An application to forensic medicine

    International Nuclear Information System (INIS)

    Samples originating from the time period after 1950 can be radiocarbon dated utilising the 14C bomb peak as a calibration curve. The applicability of 'radiocarbon dating' of recent organic human material for the determination of the time of death of humans was tested. The radiocarbon results from hair and lipid samples from individuals with known date of death were compared with the results from two individuals with unknown time of death. An estimate of the year of death for the unknowns could be derived by this way. Due to the long turnover time of collagen in human bones it is not possible to use the radiocarbon content of bone collagen for a reliable estimate. In order to study the time dependence of the collagen turnover we tested 'soft' chemical methods for the isolation of collagen from the bone matrix. First radiocarbon results of this investigation are presented

  18. The comparison of benzene and CO2 absorption methods for radioisotope 14C dating

    International Nuclear Information System (INIS)

    It had been conducted to research of age determination of carbon samples using CO2 absorption method. This method as alternative to benzene synthesis method for radioisotope 14C dating.The aim of the method is to support some hydrology research's especially groundwater dating using environmental radioisotope 14C.The results which obtain by CO2 absorption method then compared with the results of benzene synthesis method consists of background counter, standard counter, activity and age limit, age, and material cost or component. The research show that compared with benzene synthesis method, sample preparation using CO2 absorption method is more simple and relatively low cost. The use of CO2 absorption method can save the cost about 75 %. The different of both methods is age limit detection. The results of age limit detection when using CO2 absorption and synthesis benzene methods are 33,310 years and 47,533 years respectively. Whereas, based on t test, the age results of both methods for the same sample are obtained relatively equal. (author)

  19. Chemical techniques to extract organic fractions from fossil bones for accurate 14C dating

    International Nuclear Information System (INIS)

    We examined different concentrations of HCl, such as 0.4, 0.6, 0.8, 1.0 and 1.2 M, for decalcification of fossil bones and different times of 0.1 M NaOH treatment on collagens to determine the best conditions for purifying collagen through extraction of humic contaminants, and compared the alkali treatment method with the XAD-2 treatment method for several types of fossils. The yield of acid-insoluble bone fractions did not change over the range from 0.4 to 1.0 M HCl and decreased suddenly with 1.2 M HCl on decalcification, and the 14C ages of the extracted gelatins from the five decalcified fractions were unchanged, suggesting that 14C ages as those of the XAD-purified hydrolysates. The NaOH-treatment time should be less than several hours to avoid a loss of collagen. The fossil bones used are relatively well-preserved, but the alkali treatment could bring about a lot of loss of organic bone proteins for poorly-preserved bones. The XAD-2 treatment method is effective for accurate radiocarbon dating of fossil bones, if the XAD-2 resin is completely pre-cleaned

  20. From scrolls to Picasso: AMS radiocarbon dating applied to textiles, art works and artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Jull, A.J.T.; Donahue, D.J.; Beck, J.W.; Burr, G.S.; O`Malley, J.; Hewitt, L.; Biddulph, D.; Hatheway, A.L.; Lange, T.E.; Toolin, J. [Arizona Univ., Tucson, AZ (United States). NSF Arizona Accelerator Mass Spectrometry Facility

    1997-12-31

    Full text: The use of accelerator mass spectrometry (AMS) for radiocarbon dating allows us to use very small samples of carbon, <1 mg. This has opened a vast array of applications of radiocarbon dating which were difficult to do before AMS, due to sample size limitations of decay counting. We have successfully applied AMS {sup 14}C to dating of many types of textiles, including silks and linens, art works, documents and artifacts fabricated from wood, parchment, ivory and bone. For many of these types of samples, the results are often important in questions of the authenticity of these works of art and artifacts. This has encompassed a wide range of art works ranging from the Dead Sea Scrolls, the Shroud of Turin and the Chinese silk trade to the works of Raphael, Rembrandt and Picasso. Most recently, we have also dated the Vinland Map, a controversial document which shows the eastern coast of North America apparently using information from Viking voyages. An important issue in such studies is also the radiocarbon calibration curve. For some periods, most notably 1700-1950 AD we know that several changes in the {sup 14}C composition of the atmosphere make it almost impossible to date a sample during this period more precisely than the entire range. However, before this period, we have successfully dated materials to high precision. We have also studied the use of the period l900-1950 AD for {sup 14}C measurements and will present some examples where the rapid decline in {Delta} {sup 14}C can be used to date art works. The period after 1950AD also allows us to identify works fabricated from recent materials using the `spike` in {sup 14}C due to atmospheric nuclear testing. This bomb {sup 14}C has also been successfully used to identify originals from copies of works purporting to be the originals. We will discuss some artifacts, art works and forgeries, where {sup 14}C can resolve problems of authenticity (authors).

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

    International Nuclear Information System (INIS)

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

  2. Dietary reconstruction and reservoir correction of 14C dates on bones from pagan and early Christian graves in Iceland

    DEFF Research Database (Denmark)

    Sveinbjörnsdóttir, Árný E; Heinemeier, Jan; Arneborg, Jette;

    2010-01-01

    between the excavation site and the seashore. We have radiocarbon dated 47 of these skeletons and used the carbon isotopic composition (?13C) to estimate and correct for the marine reservoir effect (the 14C difference between terrestrial and mixed marine organisms). The reservoir-corrected ages lie in the...... range of AD 780?1270 (68.2% probability). Reservoir age corrections were checked by comparing 14C dates of a horse (terrestrial diet), a dog (highly marine diet), and a human (mixed diet) from the same burial. The range in measured marine protein percentage in individual diet is from about 10% up to 55...... AD 1211. Using our dietary reconstruction, his bones were about 17% marine, which is within the range of human skeletons from the same area, and the reservoir-corrected calibrated 14C age of the skeleton is in accord with the historical date....

  3. A batch preparation method for graphite targets with low background for AMS 14C measurements

    International Nuclear Information System (INIS)

    The authors have developed a method of graphitization from CO2 samples for accurate 14C measurements by accelerator mass spectrometry. Their batch method, using a sealed Vycor tube, reduces the risk of contamination during graphitization and makes it possible to prepare many samples in a short time (typically 20 samples per day). They also describe details of the target-preparation method involving carbon isotopic fractionation during graphitization, yield of graphite from CO2, ion-beam intensity of the target, and background (or blank) level estimated using bituminous coal

  4. 14C-AMS as a tool for the investigation of mercury deposition at a remote Amazon location

    International Nuclear Information System (INIS)

    We present results of the atmospheric mercury deposition rate in the Amazon region during the last 43 000 years. Lake sediment samples were collected from the Lagoa da Pata, a small and remote lake in northern Brazilian Amazon. The samples were divided in sub-samples, for C, Hg, N and 14C-AMS analyses. Three main paleoclimatic events could be identified. The mercury accumulation rates were found to be larger during the periods of the Holocene and Pleistocene associated with high temperatures and frequency of forest fires

  5. Isotopic fractionation in recombinator based 14C AMS measurements: how can we live with it?

    International Nuclear Information System (INIS)

    Isotope ratio mass spectrometry (with or without accelerator) relies on the principle that unknown samples and standards behave in the same manner in the instrument under the same conditions, allowing the isotope ratio of the unknown samples to be determined by comparison with the isotope ratios of the standards. The range of conditions within which this essential condition applies can be limited by many factors. We report here observations and tests (carried out at the Leibniz-Labor, Kiel, Germany) performed to determine the range of sample sizes/current outputs which can be safely analyzed in a given set. Since the fractionation effects are small under routine conditions, extreme situations (such as ten-fold ion current variations) had to be created where the effects would be seen more clearly. Experiments have shown that the 13C/12C variation as a function of current intensity is mainly due to a small difference in the position and direction of the 13C beam compared to that of the 12C and 14C beams at the exit of the recombinator. The cause of the 14C/12C fractionation versus current intensity is caused by side effects of the accelerator voltage stabilization which is using the 13C3+ beam

  6. The remarkable metrological history of 14C dating: from ancient Egyptian artifacts to particles of soot and grains of pollen

    International Nuclear Information System (INIS)

    Radiocarbon dating would not have been possible if 14C had not had the 'wrong' half-life - a fact that delayed its discovery. Following the discovery of this 5730 year radionuclide in laboratory experiments by Ruben and Kamen, it became clear to W. F. Libby that 14C should exist in nature, and that it could serve as a quantitative means for dating artifacts and events marking the history of civilization. The search for natural radiocarbon was a metrological challenge; the level in the living biosphere (ca. 230 Bq/kg) lay far beyond the then current state of the measurement art. This article traces the metrological history of radiocarbon, from the initial breakthrough devised by Libby, to minor (evolutionary) and major (revolutionary) advances that have brought 14C measurement from a crude, bulk (8 g carbon) dating tool, to a refined probe for dating tiny amounts of precious artifacts, and for 'molecular dating' at the 10 μg to 100 mg level. The metrological advances led to opportunities and surprises, such as the non-monotonic dendrochronological calibration curve and the 'bomb effect', that spawned new multidisciplinary areas of application, ranging from cosmic ray physics to oceanography to the reconstruction of environmental history. (author)

  7. Accelerator mass spectrometry 14C dating of lime mortars: Methodological aspects and field study applications at CIRCE (Italy)

    International Nuclear Information System (INIS)

    Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) has, recently, obtained some promising results in testing the feasibility of mortar radiocarbon dating by means of an ad hoc developed purification procedure (CryoSoniC: Cryobraking, Sonication, Centrifugation) applied to a series of laboratory mortars. Observed results encouraged CryoSoniC accuracy evaluation on genuine mortars sampled from archeological sites of known or independently constrained age (i.e., other 14C dates on different materials). In this study, some 14C measurements performed on genuine mortars will be discussed and compared with independently estimated (i.e., radiocarbon/archaeometrical dating) absolute chronologies of two Spanish sites. Observed results confirm the agreement of the CryoSoniC mortar dates with the archaeological expectations for both examined cases. Several authors reported the possibility of obtaining accurate radiocarbon dates of mortar matrices by analyzing lime lumps: binder-related particles of different sizes exclusively composed of calcium carbonate. In this paper, preliminary data for the absolute chronology reconstruction of the Basilica of the cemetery complex of Ponte della Lama (Canosa di Puglia, Italy) based on lime lumps will also be discussed. Dating accuracy will be quantified by comparing 14C data on mortar lime lumps from a funerary inscription of known age found near the Basilica, in the same study site. For this site, a comparison between absolute chronologies performed by bulk and CryoSoniC purified lime lumps, and charcoal incased in mortars (when found) will also be discussed. Observed results for this site provide evidence of how bulk lime lump dating may introduce systematic overestimations of the analyzed sample while CryoSoniC purification allows accurate dating.

  8. Accelerator mass spectrometry {sup 14}C dating of lime mortars: Methodological aspects and field study applications at CIRCE (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Marzaioli, Fabio, E-mail: fabio.marzaioli@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); Nonni, Sara, E-mail: sara.nonni@uniroma1.it [Dipartimento di Scienze della Terra, ' Sapienza' Universita di Roma (Italy); Passariello, Isabella, E-mail: isabella.passariello@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); Capano, Manuela, E-mail: manuela.capano@unina2.it [CIRCE, INNOVA and Dipartimento di Studio delle Componenti Culturali del Territorio, Seconda Universita degli Studi di Napoli, Santa Maria Capua Vetere, Caserta (Italy); Ricci, Paola, E-mail: paola.ricci@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); Lubritto, Carmine, E-mail: carmine.lubritto@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali, Caserta (Italy); De Cesare, Nicola, E-mail: nicola.decesare@unina2.it [CIRCE, INNOVA and Seconda Universita degli Studi di Napoli, Dipartimento di Scienze della Vita, Caserta (Italy); Eramo, Giacomo, E-mail: giacomo.eramo@uniba.it [Dipartimento di Scienze della Terra e Geoambientali, Universita degli Studi di Bari ' Aldo Moro' , Bari (Italy); Quiros Castillo, Juan Antonio, E-mail: quiros.castillo@ehu.es [Universidad del Pais Vasco-Euskal Herriko Unibertsitatea, Dipartimento di Geografia, Prehistoria y Arqueologia, Vitoria-Gasteiz (Spain); and others

    2013-01-15

    Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) has, recently, obtained some promising results in testing the feasibility of mortar radiocarbon dating by means of an ad hoc developed purification procedure (CryoSoniC: Cryobraking, Sonication, Centrifugation) applied to a series of laboratory mortars. Observed results encouraged CryoSoniC accuracy evaluation on genuine mortars sampled from archeological sites of known or independently constrained age (i.e., other {sup 14}C dates on different materials). In this study, some {sup 14}C measurements performed on genuine mortars will be discussed and compared with independently estimated (i.e., radiocarbon/archaeometrical dating) absolute chronologies of two Spanish sites. Observed results confirm the agreement of the CryoSoniC mortar dates with the archaeological expectations for both examined cases. Several authors reported the possibility of obtaining accurate radiocarbon dates of mortar matrices by analyzing lime lumps: binder-related particles of different sizes exclusively composed of calcium carbonate. In this paper, preliminary data for the absolute chronology reconstruction of the Basilica of the cemetery complex of Ponte della Lama (Canosa di Puglia, Italy) based on lime lumps will also be discussed. Dating accuracy will be quantified by comparing {sup 14}C data on mortar lime lumps from a funerary inscription of known age found near the Basilica, in the same study site. For this site, a comparison between absolute chronologies performed by bulk and CryoSoniC purified lime lumps, and charcoal incased in mortars (when found) will also be discussed. Observed results for this site provide evidence of how bulk lime lump dating may introduce systematic overestimations of the analyzed sample while CryoSoniC purification allows accurate dating.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-15

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

  10. 14C chronology of the oldest Scandinavian church in use. An AMS/PIXE study of lime lump carbonate in the mortar

    Science.gov (United States)

    Lindroos, Alf; Ranta, Heikki; Heinemeier, Jan; Lill, Jan-Olof

    2014-07-01

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

  11. Dating raised bogs : New aspects of AMS C-14 wiggle matching, a reservoir effect and climatic change

    NARCIS (Netherlands)

    Kilian, MR; VanDerPlicht, J; VanGeel, B; Geel, B. van

    1995-01-01

    High resolution AMS dating of Holocene raised bog deposits (Engbertsdijksvenen, The Netherlands) shows natural C-14 variations (wiggles) which can be matched with the dendrochronological calibration curve. Comparison of our results with other, conventionally dated peat cores and the Delta(14)C recor

  12. Routine performance of a new multi-counter system for high-precision 14C dating

    International Nuclear Information System (INIS)

    A new 14C detector system containing nine independently working CO2 proportional counters is described. The counter system provides sufficient measuring capacity at a precision level of sigma=+-1.5 permille (equivalent to +-12 years in age) requiring a counting time of about one week per sample. All counters are run with a common high voltage and stability is checked with a 226Ra γ-source. The amount of CO2 is 384 mmol (2 atmospheres pressure), chromatographically purified over charcoal. During this process radon is completely removed, the sample loss is negligible, and no detectable isotope fractionation occurs in the sample. The CO2 sample size control is checked by an analytical balance to a precision better than +-0.1 permille. The modern carbon count-rate (54 counts/min) is sensitively checked by running samples of the Heidelberg sodium carbonate standard (giving a count-rate of about 10 times modern), by which the entire chemical sample procedure is checked. The background lies between 3 and 3.6 counts/min depending on the position of the counters within the anticoincidence shield. The systematic background variation primarily due to barometric-pressure-induced fluctuations of cosmic-ray intensity, is eliminated by a regression with the coincidence counting rate of the 14C counters with the anticoincidence shield. Thus, the background does not significantly contribute to overall precision and reproducibility at the 14C activity levels met in oceanography and in tree-ring calibration for whose applications the detection system was designed. A micro-computer (DEC PDP 11/63) is used for data aquisition. Data transfer to the computer memory goes via a DMA-Interface (Software: 4K stand-alone system; functions: timer, counters, protocol and system check)

  13. AMS radiocarbon dating of mortar: The case study of the medieval UNESCO site of Modena

    Science.gov (United States)

    Carmine, Lubritto; Caroselli, Marta; Lugli, Stefano; Marzaioli, Fabio; Nonni, Sara; Marchetti Dori, S.; Terrasi, Filippo

    2015-10-01

    The carbon dioxide contributing to binder formation during the set of a lime mortar reflects the atmospheric 14C content at the time of construction of a building. For this reason, the 14C dating of mortars is used with increasing frequencies in archaeological and architectural research. Mortars, however, may also contain carbonaceous contaminants potentially affecting radiocarbon dating. The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) of the Second University of Naples (SUN) has recently obtained some promising results in mortar radiocarbon dating thanks to the development of a procedure (i.e. CryoSoniC/Cryo2SoniC) aiming to eliminate exogenous C contamination that may occur in a mortar. The construction history of the UNESCO World Heritage Site of Modena (Italy) is still controversial and represents a challenging case study for the application of absolute dating methodologies for different reasons. From the point of view of 14C dating, for example, given the high percentage of carbonate aggregates composing these samples, Modena mortars represent an experimental test particularly indicative of exogenous carbon sources suppression ensuring methodology accuracy. In this paper several AMS Radiocarbon dates were carried out on lime lumps with the aim to: (i) verify procedure accuracy by a comparison of the results obtainable from lime lumps dated after different treatments (i.e. bulk lime lumps vs. CryoSoniC purified lime lumps); (ii) compare different building phases absolute chronology for the medieval UNESCO site of Modena, with that assumed by historical sources in order to assess preliminary the 14C dating feasibility for of the site. Historical temporal constraints and mortar clustering, based on petrography, have been applied to define a temporal framework of the analyzed structure. Moreover, a detailed petrographic characterization of mortars was used both as a preliminary tool for the choice of samples and to infer about the

  14. Isolation, characterization and measurement of 14C content of dissolved humic matter: application to the dating of underground waters

    International Nuclear Information System (INIS)

    The aim of this thesis is to examine the feasibility of underground water dating using the measurement of the 14C content of the dissolved organic compounds (fulvic and humic acids). Four sites were selected: the Albian sandy aquifer near Soulaines (Aube, France), the deep Rupelian sandstone aquifer near Mol (Belgium), the granitic fractured massif of Peny (Limousin, France) and the chalk aquifer in the Eastern part of the Paris basin at Chalon (France). Chapter 1 gives a bibliographic synthesis of water dating knowledge using total dissolved inorganic carbon and dissolved organic compounds. The different correction models for the different carbon sources are examined in this part. Chapter 2 concerns the analytic techniques: extraction of the organic matter from water, characterization and isotopic methods, comparison of two resin extraction methods (DEAE and XAD-8 resins). Results are analyzed in chapter 3 for the characterization of the origin and evolution of organic compounds and for the selection of the most suitable organic fraction for isotope dating. The Soulaines' aquifer allows to evaluate the 14C entry signal on the organic fraction, while the 3 other aquifers with complex rock-water interactions serve as experimental fields for this new tracer. (J.S.)

  15. 14C AMS measurements in tree rings to estimate local fossil CO 2 in Bosco Fontana forest (Mantova, Italy)

    Science.gov (United States)

    Capano, Manuela; Marzaioli, Fabio; Sirignano, Carmina; Altieri, Simona; Lubritto, Carmine; D'Onofrio, Antonio; Terrasi, Filippo

    2010-04-01

    Radiocarbon concentration in atmosphere changes overtime due to anthropogenic and natural factors. Species growth preserves the local atmospheric radiocarbon signature over their life span in the annual tree rings and make it possible to use tree rings for the monitoring of changes in fossil-fuel emissions due to an increase of traffic exhaust, during the last decades. In this paper, the CIRCE AMS system has been used to measure the 14C concentration in tree rings of plants grown near an industrial area and a very busy State Road, in a forest in north Italy. Preliminary results related to tree rings of several years of plants respectively near and far the emitting sources are displayed, in order to estimate the local pollution effect. It is possible to find a dilution in years 2000 and 2006 in both the trees analysed, but not enough data have been analysed yet in order to distinguish the fossil dilution derived from the street vehicular traffic or that from the industries.

  16. Angel's share combats wine fraud: (14)C dating of wine without opening the bottle.

    Science.gov (United States)

    Fahrni, Simon M; Fuller, Benjamin T; Southon, John R

    2015-09-01

    The problem of fraud continues to plague the wine industry, and detecting cases where the original bottle has been refilled with an inferior vintage is especially difficult. A novel noninvasive procedure presented here relies on radiocarbon dating the so-called angel's share: the trace amounts of ethanol and other gases that diffuse into and through the cork as bottled wine ages and matures. These are collected by applying a vacuum to the top of the bottle and cryo-trapping the extracted gas, leaving the liquid contents untouched. Vintage verification is therefore possible without exposing the liquid contents to the atmosphere, which may render a bottle costing tens of thousands of dollars worthless for later resale and consumption. The method also has a potential for stable isotope ratio as well as chemical analysis to find indications for fraud or spoilage of fine and rare wines as well as other liquids with cork stoppers. PMID:26258285

  17. Holocene megathermal abrupt environmental changes derived from 14C dating of a coral reef at Leizhou Peninsula, South China Sea

    International Nuclear Information System (INIS)

    A depth profile of a Goniopora coral reef at Leizhou Peninsula, South China Sea, was radiocarbon dated using liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS). The time of formation, during 6600-7400 cal BP, can be divided into nine stages, each terminated by abrupt growth cessation of Goniopora and appearance of Ostrea shells. The results show that, during the Holocene megathermal (8.2-3.3 ka BP), large climatic changes have occurred in the South China Sea area

  18. New insights into the radiocarbon calibration based on 14C and U-Th dating of corals drilled offshore Tahiti (IODP Expedition #310)

    Science.gov (United States)

    Durand, Nicolas; Deschamps, Pierre; Bard, Edouard; Hamelin, Bruno; Camoin, Gilbert; Thomas, Alexander L.; Henderson, Gideon M.; Yokoyama, Yusuke

    2010-05-01

    Beyond the high-precision tree-ring calibration, the fossil corals are the most reliable archive that can be used to calibrate the radiocarbon time scale. In this contribution, we present a new radiocarbon dataset based on paired 14C and U-Th dating of fossil shallow-water tropical corals drilled offshore Tahiti during the IODP Expedition 310 'Tahiti Sea-Level'. Before 14C and U-Th analyses, rigorous screening criteria have been applied in order to select pristine aragonitic coral skeletons and avoid those displaying any post-mortem diagenesis that alters original ages. In particular, we made a significant effort to improve detection and quantification of very small amount of secondary calcite in the aragonitic coral lattice using X-ray diffraction measurements [1]. In addition, we apply a strict screening criterion based on δ234U. However, the new Tahiti dataset allow to refine the previous tolerance ranges previously adopted. More than 60 radiocarbon dates were processed at the Laboratoire de Mesure du Carbone 14 (Saclay, France) with the ARTEMIS AMS facility. This new Tahiti record provides new data to the radiocarbon calibration for two distinct time windows: for the interval between 29,200 and 36,200 years BP and for the last deglaciation period, with especially, a higher resolution (40 data) for the 14,000 - 16,000 years BP time interval. These new data extend the previous Tahiti record beyond 13,900 years BP which was the oldest U-Th age obtained on cores drilled onshore in the modern Tahiti barrier reef [2, 3]. These new results are compared with 14C chronologies from other corals, those of Barbados [4, 5] and those from other Pacific islands (Mururoa, Vanuatu, Marquesas, Christmas), and from the Cariaco Basin sediment [6, 7], the Iberian Margin sediment [8, 9] and the Bahamian speleothem [10] records. The new 14C dataset from the corals drilled offshore Tahiti allows to validate the precision and accuracy of other records either directly dated by U-Th or

  19. C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

    Directory of Open Access Journals (Sweden)

    Guadalupe de la Lanza Espino

    Full Text Available The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC, nitrogen (TN, phosphorus (TP, elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1. Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1 than those closer to the channel axis (averaging 341-516 µmol g(-1; p <0.05. The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1, whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1; p<0.05. The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4 indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16% than those near the channel axis (50.0 to 66 µmol g(-1; 0.15 to 0.21%. C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP. We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

  20. 14 C dating and isotopic composition of lacustrine sediment in the Vale do Ribeira, south-western Sao Paulo State

    International Nuclear Information System (INIS)

    This work is part of a multi and interdisciplinary study involving paleoenvironmental records based on systematic and joint actions of pollen, isotopic composition (12C, 13C and 14N, 15N) and 14C dating of lacustrine sediment. Samplings have been made in the Lagoa Grande located at Parque Estadual de Turismo do Alto Ribeira - PETAR, in the Vale do Ribeira, south-western Sao Paulo state. This integration must improve significantly the studies of vegetation and climate changes that occurred during the Late Pleistocene in the southeastern region of Brazil. The δ13C results of lacustrine sediment presented values from -23 to -30 per mille with isotopic tendencies of enrichment-depletion in the whole profile. The highest values of total organic carbon (TOC) and C/N associated with depleted δ13C values, were linked to organic matter from C3 land plant and interpreted as the presence of denser arboreal vegetation around the lake. The smallest values of TOC and C/N associated with enriched δ13C values were linked to phytoplanktonic influence and/or the presence of less dense arboreal vegetation around the lake. These fluctuations reflect changes in quality and quantity of sedimentary organic matter linked to vegetation changes and the production of organic matter within the sedimentation basin connected with lake level variations. The combination of C/N and δ13C data on a cross-plot diagram shows a general distribution of points lying close to the planktonic (algal) organic matter. However, the scattering of certain points indicates a slight contribution from C3 land plants. The variations in arboreal pollen (%AP) along the core are characterized by AP values between 40 and 80%. The 14C dating indicated Modern age at the shallow horizons to 1,030 years BP for the deeper horizon. (author)

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

    OpenAIRE

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

    2013-01-01

    The reasons for the development and collapse of Maya civilization remain controversial and historical events carved on stone monuments throughout this region provide a remarkable source of data about the rise and fall of these complex polities. Use of these records depends on correlating the Maya and European calendars so that they can be compared with climate and environmental datasets. Correlation constants can vary up to 1000 years and remain controversial. We report a series of high-resol...

  2. Design of a hybrid gas proportional counter with CdTe guard counters for 14C dating system

    International Nuclear Information System (INIS)

    Nowadays uniform, low-cost and large-size compound semiconductor detectors are available up to several square centimeters. We are trying to combine this technology with conventional gas detectors to upgrade an anticoincidence type proportional counter, Oeschger-type thin wall counter of 2.2 l, used for a 14C dating facility at the University of Tokyo. In order to increase the ratio of the signal to the background for smaller quantity of samples less than 1 g, an effective approach is to minimize the detector volume at higher gas pressure. However, the anticoincidence function suffers from such a small volume. Therefore we designed a new active wall gas counter of 0.13 l counting volume using CdTe compound semiconductor detectors as the wall of the gas proportional counter to perform anticoincidence. Simulation study showed that at noise thresholds less than 70 keV, the wall counters can reject above 99.8% of events arising from outer gamma rays. Measured noise levels of CdTe detectors were smaller than 24 keV which is low enough for 99.8% anticoincidence efficiency. The experiment showed an anticoincidence efficiency for outer gamma rays from 70% to 80%, similar to that of the old 14C counter. The lost anticoincidence efficiency results from the area of 21.74% which was not covered with CdTe due to two holes for the path of the center anode wire and slots between every two sides of CdTe detectors

  3. Design of a hybrid gas proportional counter with CdTe guard counters for {sup 14}C dating system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L. E-mail: lan@sophie.q.t.u-tokyo.ac.jp; Takahashi, H.; Hinamoto, N.; Nakazawa, M.; Yoshida, K

    2002-02-01

    Nowadays uniform, low-cost and large-size compound semiconductor detectors are available up to several square centimeters. We are trying to combine this technology with conventional gas detectors to upgrade an anticoincidence type proportional counter, Oeschger-type thin wall counter of 2.2 l, used for a {sup 14}C dating facility at the University of Tokyo. In order to increase the ratio of the signal to the background for smaller quantity of samples less than 1 g, an effective approach is to minimize the detector volume at higher gas pressure. However, the anticoincidence function suffers from such a small volume. Therefore we designed a new active wall gas counter of 0.13 l counting volume using CdTe compound semiconductor detectors as the wall of the gas proportional counter to perform anticoincidence. Simulation study showed that at noise thresholds less than 70 keV, the wall counters can reject above 99.8% of events arising from outer gamma rays. Measured noise levels of CdTe detectors were smaller than 24 keV which is low enough for 99.8% anticoincidence efficiency. The experiment showed an anticoincidence efficiency for outer gamma rays from 70% to 80%, similar to that of the old {sup 14}C counter. The lost anticoincidence efficiency results from the area of 21.74% which was not covered with CdTe due to two holes for the path of the center anode wire and slots between every two sides of CdTe detectors.

  4. Dating of the humin fraction of soil organic matter and its comparison with 14 C ages of fossil charcoal

    International Nuclear Information System (INIS)

    The radiocarbon dating of the organic matter (SOM) is a polemic subject, due mainly to the complexity of the formation of the soils and to the variable contamination from several sources. Soil samples from 4 different Brazilian localities were submitted to physical and chemical pre-treatment for the extraction of humin fraction, which is the most stable organic compound and theoretically the oldest and representative of the age of the SOM. The radiocarbon dating obtained from the total SOM and their humin fractions are compared to the 14 C ages from buried charcoals at similar depths. The radiocarbon ages obtained from such charcoals are, in most of the cases, concordant within the experimental errors of those obtained on humin fractions, or are in average 10% higher, with one exception. Thus, the ages on humin fractions could be assumed as the minimum ages for the associated soils, while the results obtained on total SOM, even at depths until 200 cm, exhibit pronounced contamination effect by modern carbon, rejuvenating their ages. (author)

  5. Paleogeography of the Austro-Hungarian Lake Neusiedl - Hansag region in historic times, based on 14C-dating

    International Nuclear Information System (INIS)

    Full text: Based on calibrated 14C-dating of several peat sections intercalating with fine-grained beds in the Hansag southeast of Lake Neusiedl we present a first approach of the paleogeography of the Austro-Hungarian border region during a time span when first settlements already existed and before the first detailed topographic maps of this region were drawn. About one hundred pits down to one metre were digged out in the Hansag region near Osli in 2003 for studying the recultivation of this regularly flooded area in an environmental geo-information system (GIS). Several sections clearly show an alternation of peat layers intersected by fine-grained fluvio-lacustrine sediments. 15 age determinations of samples from several sections underlying and overlying silty to clayey sediments allow for reconstructing the succession of longer stillwater deposits alternating with peat successions. Comparing the Hansag succession with historic records of the vicinity of Lake Neusiedl allows for a new insight in this unique development of the Lake Neusiedl - Hansag region, at present situated within the Austro-Hungarian national park. It should be recalled, that Lake Neusiedl is Central Europe's largest step lake and Austria's youngest UNESCO World Cultural Heritage site. The paleo-environment of the Lake Neusiedl - Hansag region basically can be designed in four steps by comparing the archaeological findings around Lake Neusiedl with our 14C-dating of peat layers in the Hansag region: 1: the oldest settlements in the Lake Neusiedl region date about 3600 BC, and 1700 BC respectively. During this periods the lake probably was quite smaller than today. Our 14C-dating of peat sections in the Hansag region corresponds with these findings, indicating that during a time span of approximately 2000 years until 30 Anno Domini (AD) no bigger lake existed in the Neusiedl- Hansag region. Small pieces of charcoal dating around 2300 BC can have been caused by bush fire and therefore be

  6. Terrigenous supply of 10Be and dating with 14C and 10Be in sediments of the Angola basin (SE Atlantic)

    International Nuclear Information System (INIS)

    10Be concentrations were measured in 20 (hemi)pelagic core top samples with an age control partly based on AMS 14C datings. The 10Be concentrations do not show any dependence on the bulk mass accumulation rates (MAR), but there is a significant linear correlation between 10Be accumulation rates and MAR. This correlation is best explained by terrigenous 10Be supply modified by biologic scavening and, of secondary importance, adsorption on particulate matter in the ocean surface water in the Zaire plume. The variable term of the linear regression function indicates a maximum 10Be concentration for the terrigenous component of 5x109 at.g-1, the constant suggests an oceanic 10Be precipitation of (100-530)x106 at.cm-2 ka-1. A 500 ka long record of 10Be concentrations is in agreement with the predicted values, but short-term variations in MAR obscure the expression of a long-term break in MAR about 350 ka ago. (orig.)

  7. Porous iron pellets for AMS 14C analysis of small samples down to ultra-microscale size (10-25 μgC)

    International Nuclear Information System (INIS)

    We developed the use of a porous iron pellet as a catalyst for AMS 14C analysis of small samples down to ultra-microscale size (10-25 μgC). It resulted in increased and more stable beam currents through our HVEE 4130 14C AMS system, which depend smoothly on the sample size. We find that both the expected decrease of oxalic acid standards and increase of backgrounds with decreasing sample size, due to increasing influence of contamination, are reproducible. Using a mass-dependent background correction for dead (1.0 ± 0.4 μgC) and modern (0.25 ± 0.10 μgC) contamination, we obtain reliable results for small samples down to 10 μgC and possibly smaller. Due to our low graphitization yield for ultra-small samples (increases from 40% to 80% on average with sample size), we measured graphite standards as small as 3 μgC. The standard deviation of the corrected activity is about 5% for a 10-μgC HOxII standard. Here we report the iron pellet technique, which is new to the best of our knowledge. It is generally applicable for AMS 14C laboratories that want to measure small samples down to ultra-microscale size. As an illustrative test-case, we analyze 14C data for IAEA-C5, C7 and C8 samples with masses ranging from 15 to 300 μgC.

  8. δ13C and 14C dating of sediments in Santa Cruz do Arari, Marajo Island (Brazil)

    International Nuclear Information System (INIS)

    The eastern domain of Marajo Island, in the surroundings of Santa Cruz do Arari (Para State), is occupied by holocenic sedimentary deposits, at present covered predominantly by natural grasslands. The analysis of stable carbon isotopes in organic matter of these sediments has been applied with the objective of to evaluate the paleovegetation dynamics, the retreat or the expansion of the Amazonian Forest (located in the westerner domain) over the different types of natural grasslands in Marajo Island, during Late Quaternary. From 3.60 m to 1.80 m the δ13C results are around -25 (reaching value up to -29 per mille) and indicate that the organic matter of these sediments are originated from C3 plants. In the interval of 1.80 m until 0.90 m all the samples present a gradual enrichment of 13C, indicating a higher influence of C4 plants in the vegetation cover. The intermediate δ13C values found in those depths (from -22 per mille to -18 per mille) indicate a mixture of C3 and C4 plants with gradual increase of areas with C4 plants. From 0.90 m to the shallow layer the δ13C values show a tendency to more depleted values, indicating higher influence of C3 plants in the recent and present period. The results demonstrate that the vegetation dynamics was significant in the Marajo Island from the past to the present. The chronology of these events is being determined by the 14C dating technique and possible causes (climatic, anthropogenic and/or neotectonic) for such changes investigate. (author)

  9. AMS radiocarbon dating of cemetery of Jin Marquises in China

    CERN Document Server

    Wu, X; Wang, J; Guo, Z; Liu, K; Lü, X; Ma, H; Li, K; Yuan, J; Cai, L

    2000-01-01

    Bones are very important samples to determine the hosts of the cemetery of Jin Marquises which were excavated at Tianma-Qucun site in Shanxi Province in China. In order to obtain accurate AMS radiocarbon dates, bones were pretreated by two kinds of methods, the gelatin-extraction method and the amino-acid method. Charcoals collected from the same sites were also used. The measured dates agree with historical record.

  10. Natural 14C variations

    International Nuclear Information System (INIS)

    This thesis deals with the natural variations in the atmospheric 14C activity, their geophysical origin and their impact on radiocarbon dating. Studies confirm the idea that one is dealing with a mechanism of a certain regularity. The correlation between a 14C variation during the Little Ice Age and the absence of sunspots on the solar surface suggest the sun to be responsible for some kind of modulation of the galactic cosmic ray spectrum. The background of a changing natural 14C level is relevant when studying the antropogenic perturbation of the atmospheric 14C concentration by the addition of CO2 from fossil fuel combustion. The results presented point to a Suess effect over the past 150 years of about 20 per thousand, but also show a local dilution effect. If this local effect is present over large continental parts of the Northern Hemisphere this will put limits to the use of tree ring 14C measurements for testing carbon reservoir models. Finally the influence of 14C variations upon the interpretations of 14C dates for archaeological and geological purposes has been investigated. It is shown that care must be taken especially in the interpretation of highly accurate 14C data of material only covering a few years of growth. One geological example illustrates that 14C variations can easily be interpretated as alternating fast and slow rises of the sea level. (Auth.)

  11. Measuring transfer of 14C-PCB from maternal diet to milk in a goat model using an accelerator mass spectrometer (AMS)

    International Nuclear Information System (INIS)

    Environmental pollutants pose a substantial risk to nursing infants. Many of these toxicants (i.e. PCBs, PBDEs, mercury) are passed from the maternal diet to the nursing infant in breast milk. Determining the toxicokinetics has been difficult to measure due to ethical limitations. Since extremely small amounts of 14C can be measured using Accelerator Mass Spectrometry (AMS), a goat model was used to establish a minimum oral dose of 14C-labeled PCB (2,2',4,4',5,5'-hexachlorobiphenyl-UL-14C) that could be given to a lactating animal and traced into the milk. An oral dose of 66 nCi/kg body weight (1.84 μg PCB/kg bw) was administered. Plasma and milk samples were collected for 2 months after dosing. The concentration of 14C label reached a peak value of 1.71 ng/ml PCB equivalents in the milk on day 2 and then declined to about 135 pg/ml PCB equivalents in the milk at 3 weeks. A second goat was administered a smaller dose (22 nCi/kg bw; 616 ng PCB/kg bw). A peak concentration of 485 pg PCB equivalents/ml milk occurred at 3 days and declined to 77.6 pg PCB equivalents/ml milk by 3 weeks. Our results indicated that an even lower dosage of labeled-PCB could be used due to the extreme sensitivity of AMS measurement. Extrapolating from current data it is estimated that the dose could be reduced by a factor of 20 (31 ng PCB/kg bw; 1.1 nCi/kg bw) and still be detectable after 2 months. Thus, the potential exists for developing protocols for studying toxicokinetics in humans using radiologically- and toxicologically-benign doses of labeled environmental toxicants

  12. The rates of carbon cycling in several soils from AMS14C measurements of fractionated soil organic matter

    International Nuclear Information System (INIS)

    14C mean residence times (MRT) of fractionated organic matter are reported for three pre-bomb soil profiles. Comparisons of organic matter extracted with acid and base showed that the longest MRTs were associated with the non-acid-hydrolysable fraction. The MRT of organic matter in a soil layer represents a combination of the rates of several processes, including decay to CO2 and transport out of the layer. In some instances (notably in the A horizon of the Podzol soil studied in this paper), the MRT is dominated by the rate of transport, rather than the rate of decay. Thus it is important to use the distribution and balance of carbon in the soil profile to assess the meaning of the MRT with respect to influencing atmospheric CO2

  13. Are the ‘new’ AMS Varna dates older?

    Directory of Open Access Journals (Sweden)

    Tanya Dzhanfezova

    2013-06-01

    Full Text Available The paper elaborates on the AMS dating results obtained for the Chalcolithic cemetery near Varna, located on the western Black Sea coast in northeastern Bulgaria. The focus here is not on the comparison between absolute dates acquired for various sites from the middle and late Chalcolithic period in the region. It is rather on the examination of the main approaches towards suggested chronological frameworks. Divided into three parts, the text reviews regional methods for proceeding conventional radiocarbon dates (II A and such, related to the later AMS measurement of bone collagen (II B. Both approaches are considered as deserving more attention with regard to the problematic aspects that may affect the acquisition of reliable results. The 19 new AMS Varna dates are found important for chronological revisions. However, at this stage they alone are not considered sufficient for inarguable modifications of the schemes (III. Along with identification of major factors that should be taken into account when dealing with the chronological debates in the specified region, strategies for solving some of the issues are also suggested.

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

    International Nuclear Information System (INIS)

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

  15. The interpretation of archaeological dates from an AMS perspective

    International Nuclear Information System (INIS)

    The XVII century saw the establishment of the scientific method and scholars such as Galileo were giving excellent contributions to a variety of fields ranging from the natural sciences to the humanities. At the dawn of the new millenium, after a period of excessive specialization, the scientific climate is once again encouraging broad collaborations across different disciplines. For projects involving AMS measurements in general and radiocarbon dating in particular, the benefits of this new trend are numerous. For example, the full potential of the radiocarbon dating method can be exploited only through the mutual understanding of the problems related to sample selection, chemical preparation, AMS measurement, data analysis and interpretation. This paper is intended to enhance the exchange of information by reporting to our current and potential collaborators about the latest technical developments undertaken at the ANTARES AMS facility at ANSTO. Furthermore, we will present two splendid examples of collaborative research: the radiocarbon dating of a replica of a famous chesspiece and the archaeological investigations at the ancient settlement of Sos Hoyuk (north-eastern Anatolia, Turkey) where the multidisciplinary approach was the key to a better understanding of the social structure, settlement patterns, land use and cultural contact, especially with the lands of Trans-Caucasus. (author). 12 refs., 4 figs

  16. 14C dating and isotopic composition of mangrove soil in the Parque Estadual da Ilha do Cardoso, Southern Sao Paulo State

    International Nuclear Information System (INIS)

    This work is part of a study involving paleoenvironmental records based on pollen analysis, isotopic composition (12C, 13C and 14N, 15N) and 14C dating of mangrove soil. Samplings have been made in the Jacariu mangrove located at Parque Estadual da Ilha do Cardoso, Cananeia, southern Sao Paulo state. This study must improve significantly the studies of vegetation and climate changes that occurred during the late Holocene (approximately the last 2000 years) in the southeastern region of Brazil. The δ13C results of mangrove soil presented values from -24 to -26 per mille The values of TOC and C/N associated with δ13C values indicated the predominance of organic matter from C3 land plant and phytoplankton (algal) in the whole profile. The 14C dating indicated Modern age at the shallow horizons to 1810 years B.P. for the deeper horizon. (author)

  17. Geological-geomorphological analysis and 14C dating of submoraine organogenic deposits within the Renardbreen outer margin, Wedel Jarlsberg Land, Spitsbergen

    International Nuclear Information System (INIS)

    Amazing organogenic deposits were encountered within the terminal moraine zone of Renardbreen, north-western part of Wedel Jarlsberg Land, Spitsbergen. Pollen analyses and 14C dating located the deposits at the Middle Late Subatlantic transition. The position of these deposits indicate possible glacial advances 3500 - 2000 years BP and during the Little Ice Age, respectively. Remnants of human activity at least as old as the 9th century were also found within organogenic deposits. 36 refs., 5 figs

  18. Analysis of 14C and 13C in teeth provides precise birth dating and clues to geographical origin

    OpenAIRE

    K, Alkass; BA, Buchholz; H, Druid; Spalding KL

    2011-01-01

    The identification of human bodies in situations when there are no clues as to the person’s identity from circumstantial data, poses a difficult problem to investigators. The determination of age and sex of the body can be crucial in order to limit the search to individuals that are a possible match. We analyzed the proportion of bomb pulse derived carbon-14 (14C) incorporated in the enamel of teeth from individuals from different geographical locations. The ‘bomb pulse’ refers to a significa...

  19. Dating of the humin fraction of soil organic matter and its comparison with {sup 14} C ages of fossil charcoal; Datacao da fracao humina da materia organica do solo e sua comparacao com idades {sup 14} C de carvoes fosseis

    Energy Technology Data Exchange (ETDEWEB)

    Gouveia, Susy Eli Marques; Pessenda, Luiz Carlos Ruiz [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil); Aravena, Ramon [Waterloo Univ., ON (Canada)

    1999-12-01

    The radiocarbon dating of the organic matter (SOM) is a polemic subject, due mainly to the complexity of the formation of the soils and to the variable contamination from several sources. Soil samples from 4 different Brazilian localities were submitted to physical and chemical pre-treatment for the extraction of humin fraction, which is the most stable organic compound and theoretically the oldest and representative of the age of the SOM. The radiocarbon dating obtained from the total SOM and their humin fractions are compared to the {sup 14} C ages from buried charcoals at similar depths. The radiocarbon ages obtained from such charcoals are, in most of the cases, concordant within the experimental errors of those obtained on humin fractions, or are in average 10% higher, with one exception. Thus, the ages on humin fractions could be assumed as the minimum ages for the associated soils, while the results obtained on total SOM, even at depths until 200 cm, exhibit pronounced contamination effect by modern carbon, rejuvenating their ages. (author)

  20. Validation of OSL and 14C dating of initial soils in Late-Holocene polycyclic drift-sand deposits (Weerterbergen, S.E. Netherlands)

    Science.gov (United States)

    van Mourik, J. M.; Schilder, M. L. M.; Wallinga, J.

    2009-04-01

    Late glacial aeolian coversand dominates the surface geology of the eastern part of the province Noord-Brabant (Netherlands). During prehistoric and early historic time, forest grazing, wood cutting and shifting cultivation gradually transformed natural forest into heath land. Subsequently the use of the heath for the production of organic manure during the period of plaggen agriculture (from early Middle Ages to the invention of chemical fertilizers around 1900 AD) resulted in the comeback of sand drifting and locally the coversand landscape transformed into a driftsand landscape with characteristic new landforms and soils. Polycyclic driftsand deposits are paleoecological records of alternating instable (sand drifting) and stable (soil formation) phases in landscape development. Interpretation of paleoecological information, derived from these records, requires accurate knowledge of the geochronology. Traditionally radiocarbon dating was applied on SOM (soil organic matter), extracted from humic AE horizons of buried initial soils (micropodzols), developed in driftsand beds. In polycyclic driftsand sequences, micropozols indicate a stable period in landscape development. One of the research questions in driftsand landscapes was related to the distribution and age of micropodzols: Are they the result of just local or more regional events in landscape evolution? The calibrated 14C ages of seven selected of extracted humic acids of micropozols range from 340 - 1950 AD. Based on these results, the alternation of instable and stable periods in landscape development seems to be controlled by local events. But to understand the development of polycyclic sequences, we need more information than just the 14C ages of micropodzols. Every cycle of a polycyclic sequence reflects a period of landscape instability (deposition) and landscape stability (soil development). A 14C based chronological framework does not allow the indicate the available time for deposition and for

  1. 14C-Dated oxygen-isotope plot of ice-wedge ice of Chara River, Transbaikal'e

    International Nuclear Information System (INIS)

    For refining the time of formation of ice-wedge in southern Siberia the radiocarbon dating of organic phyto materials (wood, peat) from the ice vein enclosing deposits in the primary terrace of the Chara River was made. All the 19 datings fall in the range from 10 to 7.5 thousand years and the period coincides with the first half of the Holocene optimum for the Siberian areas. Isotope composition (18O) of the ices suggests that normally they formed due to water from melted snow

  2. Using an independent geochronology based on palaeomagnetic secular variation (PSV) and atmospheric Pb deposition to date Baltic Sea sediments and infer 14C reservoir age

    Science.gov (United States)

    Lougheed, Bryan C.; Snowball, Ian; Moros, Matthias; Kabel, Karoline; Muscheler, Raimund; Virtasalo, Joonas J.; Wacker, Lukas

    2012-05-01

    Dating of sediment cores from the Baltic Sea has proven to be difficult due to uncertainties surrounding the 14C reservoir age and a scarcity of macrofossils suitable for dating. Here we present the results of multiple dating methods carried out on cores in the Gotland Deep area of the Baltic Sea. Particular emphasis is placed on the Littorina stage (8 ka ago to the present) of the Baltic Sea and possible changes in the 14C reservoir age of our dated samples. Three geochronological methods are used. Firstly, palaeomagnetic secular variations (PSV) are reconstructed, whereby ages are transferred to PSV features through comparison with varved lake sediment based PSV records. Secondly, lead (Pb) content and stable isotope analysis are used to identify past peaks in anthropogenic atmospheric Pb pollution. Lastly, 14C determinations were carried out on benthic foraminifera (Elphidium spec.) samples from the brackish Littorina stage of the Baltic Sea. Determinations carried out on smaller samples (as low as 4 μg C) employed an experimental, state-of-the-art method involving the direct measurement of CO2 from samples by a gas ion source without the need for a graphitisation step - the first time this method has been performed on foraminifera in an applied study. The PSV chronology, based on the uppermost Littorina stage sediments, produced ten age constraints between 6.29 and 1.29 cal ka BP, and the Pb depositional analysis produced two age constraints associated with the Medieval pollution peak. Analysis of PSV data shows that adequate directional data can be derived from both the present Littorina saline phase muds and Baltic Ice Lake stage varved glacial sediments. Ferrimagnetic iron sulphides, most likely authigenic greigite (Fe3S4), present in the intermediate Ancylus Lake freshwater stage sediments acquire a gyroremanent magnetisation during static alternating field (AF) demagnetisation, preventing the identification of a primary natural remanent magnetisation for

  3. High-resolution 14C dating of a 25,000-year lake-sediment record from equatorial East Africa

    NARCIS (Netherlands)

    M. Blaauw; B. van Geel; I. Kristen; B. Plessen; A. Lyaruu; D.R. Engstrom; J. van der Plicht; D. Verschuren

    2011-01-01

    We dated a continuous, ∼22-m long sediment sequence from Lake Challa (Mt. Kilimanjaro area, Kenya/Tanzania) to produce a solid chronological framework for multi-proxy reconstructions of climate and environmental change in equatorial East Africa over the past 25,000 years. The age model is based on a

  4. Summed Probability Distribution of 14C Dates Suggests Regional Divergences in the Population Dynamics of the Jomon Period in Eastern Japan.

    Science.gov (United States)

    Crema, Enrico R; Habu, Junko; Kobayashi, Kenichi; Madella, Marco

    2016-01-01

    Recent advances in the use of summed probability distribution (SPD) of calibrated 14C dates have opened new possibilities for studying prehistoric demography. The degree of correlation between climate change and population dynamics can now be accurately quantified, and divergences in the demographic history of distinct geographic areas can be statistically assessed. Here we contribute to this research agenda by reconstructing the prehistoric population change of Jomon hunter-gatherers between 7,000 and 3,000 cal BP. We collected 1,433 14C dates from three different regions in Eastern Japan (Kanto, Aomori and Hokkaido) and established that the observed fluctuations in the SPDs were statistically significant. We also introduced a new non-parametric permutation test for comparing multiple sets of SPDs that highlights point of divergences in the population history of different geographic regions. Our analyses indicate a general rise-and-fall pattern shared by the three regions but also some key regional differences during the 6th millennium cal BP. The results confirm some of the patterns suggested by previous archaeological studies based on house and site counts but offer statistical significance and an absolute chronological framework that will enable future studies aiming to establish potential correlation with climatic changes. PMID:27128032

  5. Summed Probability Distribution of 14C Dates Suggests Regional Divergences in the Population Dynamics of the Jomon Period in Eastern Japan.

    Directory of Open Access Journals (Sweden)

    Enrico R Crema

    Full Text Available Recent advances in the use of summed probability distribution (SPD of calibrated 14C dates have opened new possibilities for studying prehistoric demography. The degree of correlation between climate change and population dynamics can now be accurately quantified, and divergences in the demographic history of distinct geographic areas can be statistically assessed. Here we contribute to this research agenda by reconstructing the prehistoric population change of Jomon hunter-gatherers between 7,000 and 3,000 cal BP. We collected 1,433 14C dates from three different regions in Eastern Japan (Kanto, Aomori and Hokkaido and established that the observed fluctuations in the SPDs were statistically significant. We also introduced a new non-parametric permutation test for comparing multiple sets of SPDs that highlights point of divergences in the population history of different geographic regions. Our analyses indicate a general rise-and-fall pattern shared by the three regions but also some key regional differences during the 6th millennium cal BP. The results confirm some of the patterns suggested by previous archaeological studies based on house and site counts but offer statistical significance and an absolute chronological framework that will enable future studies aiming to establish potential correlation with climatic changes.

  6. Summed Probability Distribution of 14C Dates Suggests Regional Divergences in the Population Dynamics of the Jomon Period in Eastern Japan

    Science.gov (United States)

    Habu, Junko; Kobayashi, Kenichi; Madella, Marco

    2016-01-01

    Recent advances in the use of summed probability distribution (SPD) of calibrated 14C dates have opened new possibilities for studying prehistoric demography. The degree of correlation between climate change and population dynamics can now be accurately quantified, and divergences in the demographic history of distinct geographic areas can be statistically assessed. Here we contribute to this research agenda by reconstructing the prehistoric population change of Jomon hunter-gatherers between 7,000 and 3,000 cal BP. We collected 1,433 14C dates from three different regions in Eastern Japan (Kanto, Aomori and Hokkaido) and established that the observed fluctuations in the SPDs were statistically significant. We also introduced a new non-parametric permutation test for comparing multiple sets of SPDs that highlights point of divergences in the population history of different geographic regions. Our analyses indicate a general rise-and-fall pattern shared by the three regions but also some key regional differences during the 6th millennium cal BP. The results confirm some of the patterns suggested by previous archaeological studies based on house and site counts but offer statistical significance and an absolute chronological framework that will enable future studies aiming to establish potential correlation with climatic changes. PMID:27128032

  7. {sup 14}C dating and isotopic composition of mangrove soil in the Parque Estadual da Ilha do Cardoso, Southern Sao Paulo State

    Energy Technology Data Exchange (ETDEWEB)

    Vidotto, Elaine; Pessenda, Luiz Carlos Ruiz; Gouveia, Susy Eli M.; Bendassolli, Jose Albertino [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)]. E-mails: evidotto@cena.usp.br; pessenda@cena.usp.br; susyeli@cena.usp.br; jab@cena.usp.br; Ricardi-Branco, Fresia [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)]. E-mail: fresia@ige.unicamp.br; Aravena, Ramon [University of Waterloo, Ontario (Canada)]. E-mail: roaraven@sciborg.uwaterloo.ca

    2007-07-01

    This work is part of a study involving paleoenvironmental records based on pollen analysis, isotopic composition ({sup 12}C, {sup 13}C and {sup 14}N, {sup 15}N) and {sup 14}C dating of mangrove soil. Samplings have been made in the Jacariu mangrove located at Parque Estadual da Ilha do Cardoso, Cananeia, southern Sao Paulo state. This study must improve significantly the studies of vegetation and climate changes that occurred during the late Holocene (approximately the last 2000 years) in the southeastern region of Brazil. The {delta}{sup 13}C results of mangrove soil presented values from -24 to -26 per mille The values of TOC and C/N associated with {delta}{sup 13}C values indicated the predominance of organic matter from C{sub 3} land plant and phytoplankton (algal) in the whole profile. The {sup 14}C dating indicated Modern age at the shallow horizons to 1810 years B.P. for the deeper horizon. (author)

  8. Redundant 230Th/ 234U/ 238U, 231Pa/ 235U and 14C dating of fossil corals for accurate radiocarbon age calibration

    Science.gov (United States)

    Chiu, Tzu-Chien; Fairbanks, Richard G.; Mortlock, Richard A.; Cao, Li; Fairbanks, Todd W.; Bloom, Arthur L.

    2006-09-01

    230Th/ 234U/ 238U dating of fossil corals by mass spectrometry is remarkably precise, but some samples exposed to freshwater over thousands of years may gain and/or lose uranium and/or thorium and consequently yield inaccurate ages. Although a δ 234U initial value equivalent to modern seawater and modern corals has been an effective quality control criterion, for samples exposed to freshwater but having δ 234U initial values indistinguishable from modern seawater and modern corals, there remains a need for additional age validation in the most demanding applications such as the 14C calibration (Fairbanks et al., 2005. Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paired 230Th/ 234U/ 238U and 14C dates on pristine corals. Quaternary Science Reviews 24(16-17), 1781-1796). In this paper we enhance screening criteria for fossil corals older than 30,000 years BP in the Fairbanks0805 radiocarbon calibration data set (Fairbanks et al., 2005) by measuring redundant 230Th/ 234U/ 238U and 231Pa/ 235U dates via multi-collector magnetic sector inductively coupled plasma mass spectrometry (MC-MS-ICPMS) using techniques described in Mortlock et al. (2005. 230Th/ 234U/ 238U and 231Pa/ 235U ages from a single fossil coral fragment by multi-collector magnetic-sector inductively coupled plasma mass spectrometry. Geochimica et Cosmochimica Acta 69(3), 649-657.). In our present study, we regard paired 231Pa/ 235U and 230Th/ 234U/ 238U ages concordant when the 231Pa/ 235U age (±2 σ) overlaps with the associated 230Th/ 234U/ 238U age (±2 σ). Out of a representative set of 11 Fairbanks0805 (Fairbanks et al., 2005) radiocarbon calibration coral samples re-measured in this study, nine passed this rigorous check on the accuracy of their 230Th/ 234U/ 238U ages. The concordancy observed between 230Th/ 234U/ 238U and 231Pa/ 235U dates provides convincing evidence to support closed system behavior of these fossil corals and validation of their 230Th/ 234U/ 238U

  9. Forensic applications of 14C at CIRCE

    Science.gov (United States)

    Marzaioli, F.; Fiumano, V.; Capano, M.; Passariello, I.; Cesare, N. De.; Terrasi, F.

    2011-12-01

    The decreasing trend of the radiocarbon pulse produced during the atmospheric tests of nuclear weapons (bomb-carbon) coupled with high sensitivity accelerator mass spectrometry (AMS) measurements, drastically increased the precision of radiocarbon age determinations since the second part of the sixties, allowing the application of radiocarbon AMS to a wide range of studies previously not directly involving conventional radiocarbon dating (i.e. food authenticity, forensic, biochemistry). In the framework of authenticity evaluation of artworks, high precision radiocarbon ( 14C) AMS measurements (Δ R/ R Leonardo da Vinci. Bomb- 14C dating on the lipid and collagen fractions of bones allows the evaluation of the year of the death of the individuals by means of ad hoc calibration data sheet with the typical few years precision and difference between collagen apparent age and the year of death appeared in agreement with the age of one individual estimated by dating of tooth collagen. Conventional radiocarbon dating on both wood and wood extracted cellulose leads to an estimation of the portrait wood board age (2σ) of 1459-1524 AD (57% relative probability), 1571-1631 AD interval (42% relative probability).and 1559-1563 AD (1% relative probability). These results attribute with the highest relative probability an age comprised within the life span of Leonardo (1452-1519) to the support.

  10. 14C dating of freshwater carbonate sediments with special reference to calcareous tufas and laminated lake sediments

    International Nuclear Information System (INIS)

    The sequence of laminated sediment of the lake Gosciaz, Poland, covers more than 13,000 years and is actually the longest sequence known so far. Besides of reconstructing past environmental changes, this sequence offers an excellent possibility for studying natural C-14 variations and calibrating the C-14 time scale in a range beyond 6,000 years B.P. The floating varve chronology based on previously taken sediment cores which cover a period of 9,682 years, has been improved by this study. Relative water level changes of the lake during the past 11,500 years have been reconstructed by means of C-14 and C-13 measurements carried out on carbonate fractions of the lake sediments. Periodical variations in the width of annual layers were found. The periods identified are 11 years and 22 years (solar cycle), 35 years (Bruckner cycle), and 200 years. The ratio of summer layer width and the total width of the annual layer shows secular changes which correlate with paleotemperature records. The duration of the Younger Dryas period was determined by combining the floating varve chronology with isotope and pollen analyses of the sediment material. A value of 1,500 years was found. The study also included radiocarbon dating of calcareous tufa taken from different study areas. 26 refs, 26 figs, 6 tabs

  11. Forensic applications of 14C at CIRCE

    International Nuclear Information System (INIS)

    The decreasing trend of the radiocarbon pulse produced during the atmospheric tests of nuclear weapons (bomb-carbon) coupled with high sensitivity accelerator mass spectrometry (AMS) measurements, drastically increased the precision of radiocarbon age determinations since the second part of the sixties, allowing the application of radiocarbon AMS to a wide range of studies previously not directly involving conventional radiocarbon dating (i.e. food authenticity, forensic, biochemistry). In the framework of authenticity evaluation of artworks, high precision radiocarbon (14C) AMS measurements (ΔR/R 14C dating achieved high precision measurements opening the opportunity to these kinds of applications. This paper presents the main results obtained from radiocarbon measurements on a set of bone samples analyzed for the determination of the post-mortem interval in the framework of an unsolved case investigated by the Rome prosecutor office. The chronological characterization of the wooden support of the “Acerenza portrait” is also presented with the aim to evaluate its age and to further investigate the possibility to attribute this artwork to Leonardo da Vinci. Bomb-14C dating on the lipid and collagen fractions of bones allows the evaluation of the year of the death of the individuals by means of ad hoc calibration data sheet with the typical few years precision and difference between collagen apparent age and the year of death appeared in agreement with the age of one individual estimated by dating of tooth collagen. Conventional radiocarbon dating on both wood and wood extracted cellulose leads to an estimation of the portrait wood board age (2σ) of 1459–1524 AD (57% relative probability), 1571–1631 AD interval (42% relative probability).and 1559–1563 AD (1% relative probability). These results attribute with the highest relative probability an age comprised within the life span of Leonardo (1452–1519) to the support.

  12. The significance of 14 C dating on the reconstruction of paleo-sea level and in the quaternary barrier evolution in the State of Parana, Brazil

    International Nuclear Information System (INIS)

    The C-14 datations are one of the main tools to reconstruct paleo-seal level and to understand the Quaternary barriers evolution. Thi paper discuss the significant of 33 14 C date dated samples on paleo-sea level reconstruction and in the interpretation of Upper Pleistocene and Holocene barrier evolution in the State of Parana. We have concluded that: it is unlikely that humic and fulvic acids are influencing the dating of wood samples from sediments impregnated with organic matter; in situ reef remains, composed mainly of vermetid tubes of Petaloconchus (Macrophragma) varians, are the most precise and reliable paleo-sea level indicators found in the coast of Parana, showing a margin of error around ± 1,0 m; the height of the shell banks, composed mainly of Anamalocardia brasiliana and containing abundant shells in live position, indicates a paleo-sea level equal or higher than the mean sea level during the organisms lifetime; interpretation of paleo-sea level through composed indicators provide only maximum ages because the dated-sample could be older than the sedimentary structure used determine paleo-sea level; the marine paleo-sea level indicators suggest that, during the late Pleistocene, the sea reached > 4.0 m above present sea level; dating of vermetid tubes indicates that the maximum Holocene sea level on the Parana coast occurred between 5370 and 4630 years B.P.; the Holocene high maximum was about 3.5-3.6 ± 1.0 m; after the maximum, the sea level gradually dropped, but the possibility of the occurrence of decimeter oscillations is not rejected; the paleo-seal level inferred from mollusk banks, mainly composed of Anomalocardia brasiliana, and composed indicators, such as sedimentary structures associated with transported shells and wood fragment, agree with paleo-sea levels inferred from vermetid tubes on the Parana coast. (author)

  13. Retrospective study of 14C concentration in the vicinity of NPP Jaslovské Bohunice using tree rings and the AMS technique

    Science.gov (United States)

    Ješkovský, Miroslav; Povinec, Pavel P.; Steier, Peter; Šivo, Alexander; Richtáriková, Marta; Golser, Robin

    2015-10-01

    Atmospheric radiocarbon has been monitored around the Nuclear Power Plant (NPP) Jaslovské Bohunice (Slovakia) using CO2 absorption in NaOH solution since 1969. In 2012, tree ring samples were collected from Tilia cordata using an increment borer at Žlkovce monitoring station situated close to the Bohunice NPP. Each tree ring was identified and graphite targets were produced for 14C analysis by accelerator mass spectrometry. The 14C concentrations obtained from the tree-ring samples have been in a reasonable agreement with the averaged annual 14C concentrations in atmospheric CO2.

  14. 14C analysis via intracavity optogalvanic spectroscopy

    International Nuclear Information System (INIS)

    A new ultra sensitive laser-based analytical technique, intracavity optogalvanic spectroscopy (ICOGS), allowing extremely high sensitivity for detection of 14C-labeled carbon dioxide has recently been demonstrated. Capable of replacing accelerator mass spectrometers (AMS) for many applications, the technique quantifies zeptomoles of 14C in sub micromole CO2 samples. Based on the specificity of narrow laser resonances coupled with the sensitivity provided by standing waves in an optical cavity, and detection via impedance variations, limits of detection near 10-1514C/12C ratios have been obtained with theoretical limits much lower. Using a 15 W 14CO2 laser, a linear calibration with samples from 5 x 10-15 to >1.5 x 10-12 in 14C/12C ratios, as determined by AMS, was demonstrated. Calibration becomes non-linear over larger concentration ranges due to interactions between CO2 and buffer gas, laser saturation effects and changes in equilibration time constants. The instrument is small (table top), low maintenance and can be coupled to GC or LC input. The method can also be applied to detection of other trace entities. Possible applications include microdosing studies in drug development, individualized sub-therapeutic tests of drug metabolism, carbon dating and real time monitoring of atmospheric radiocarbon.

  15. Forensic applications of 14C at CIRCE

    Science.gov (United States)

    Marzaioli, F.; Fiumano, V.; Capano, M.; Passariello, I.; Cesare, N. De.; Terrasi, F.

    2011-12-01

    The decreasing trend of the radiocarbon pulse produced during the atmospheric tests of nuclear weapons (bomb-carbon) coupled with high sensitivity accelerator mass spectrometry (AMS) measurements, drastically increased the precision of radiocarbon age determinations since the second part of the sixties, allowing the application of radiocarbon AMS to a wide range of studies previously not directly involving conventional radiocarbon dating (i.e. food authenticity, forensic, biochemistry). In the framework of authenticity evaluation of artworks, high precision radiocarbon ( 14C) AMS measurements (Δ R/ R < 0.3%) reduce the conventional uncertainty of the dating to few decades, allowing precise age estimation of materials containing carbon (C). The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) during its activity on AMS 14C dating achieved high precision measurements opening the opportunity to these kinds of applications. This paper presents the main results obtained from radiocarbon measurements on a set of bone samples analyzed for the determination of the post-mortem interval in the framework of an unsolved case investigated by the Rome prosecutor office. The chronological characterization of the wooden support of the "Acerenza portrait" is also presented with the aim to evaluate its age and to further investigate the possibility to attribute this artwork to Leonardo da Vinci. Bomb- 14C dating on the lipid and collagen fractions of bones allows the evaluation of the year of the death of the individuals by means of ad hoc calibration data sheet with the typical few years precision and difference between collagen apparent age and the year of death appeared in agreement with the age of one individual estimated by dating of tooth collagen. Conventional radiocarbon dating on both wood and wood extracted cellulose leads to an estimation of the portrait wood board age (2σ) of 1459-1524 AD (57% relative probability), 1571-1631 AD interval (42

  16. AMS-dated mollusks in beach ridges and berms document Holocene sea-level and coastal changes in northeastern Kuwait Bay

    Science.gov (United States)

    Reinink-Smith, Linda M.

    2015-09-01

    In northeastern Kuwait, ancient beach ridges and associated berms are separated from the present shoreline by a 4-6 km-wide sabkha. A diverse mollusk fauna in the beach ridges attests to a former open marine environment. A total of 21 AMS dates were obtained in this study. Thirteen mollusk samples from beach ridges yielded AMS dates ranging from ~ 6990 cal yr BP in the southeast to ~ 3370 cal yr BP in the northwest, suggesting a southeast to northwest age progression during the Holocene transgression. In contrast, four samples from berms throughout the study area yielded AMS dates of 5195-3350 cal yr BP showing no age progression; these berms consist largely of Conomurex persicus gastropods that aggregated by storms during a highstand at ~ 5000-3500 cal yr BP. The berms are presently at ~ + 6 m above sea level, 2-3 m above the beach ridges. Human settlements were common on the ridge crests before and after the highstand. Regression to present-day sea level commenced after the highstand, which is when the sabkha began forming. A landward, marine-built terrace, which yielded AMS dates > 43,500 14C yr BP, probably formed during Marine Oxygen Isotope Stage 5e and hence is not genetically related to the beach ridges.

  17. Development of a method to measure the concentration of 14C in the stack air of nuclear power plants by accelerator mass spectrometry (AMS)

    International Nuclear Information System (INIS)

    C-14, a pure low-energetic beta-emitter, is produced through various nuclear reactions in nuclear power plants. Some of this C-14 is air-borne and is transported via the ventilation system through the stack of the power station and is integrated in living matter in the surroundings of the plant. The long half-life of the isotope (T1/2=5730 years) and the biological importance of carbon may lead to a not negligible contribution of the radiation dose for those living in the neighbourhood of nuclear power plants. C-14 has earlier been measured radiometrically with mainly two different methods, using proportional counters or liquid scintillators. In this report a new method is described, using an accelerator based technique. accelerator mass spectrometry (AMS). This technique has at least three advantages over the radiometrical methods. It requires only a few litres of gas per sample, which is 100-1000 times less compared to the radiometrical methods. It is insensitive to the beta and gamma rays from other radioactive isotopes in the stack air. The measuring time with AMS, about 20 minutes per sample, is considerably shorter compared to the radiometrical methods, which demand several hours per sample. The integrity of the AMS method is high and it might be convenient for regulatory supervision. (22 refs.)

  18. A multi-isotope (B, Sr, O, H) and age dating (3H-3He, 14C) study of groundwater from Salinas Valley, California

    International Nuclear Information System (INIS)

    This study investigates the chemical and isotopic compositions of groundwater from Salinas Valley, California in order to constrain the origin and rates of groundwater contamination. We use an array of geochemical, environmental isotopes of water (18O/16O, D/H, 3H-3He) and dissolved salts (11B/10B, 87Sr/86Sr, 14C) to establish a reliable conceptual model for the basin. The basin consists of a deep, confined '400-foot aquifer' overlying the '180-foot aquifer' and a perched aquifer, all made up of sand, gravels, clays, and alluvial deposits. Our 3H-3He, 14C, and δ18O results show different replenishment zones and rates in the basin: (1) rapid replenishment (14C concentrations of 72 to 98 pmc) in the perched and 180-foot aquifers in the northern area; (2) fast arrival (15 years) of 18O- and NO3-enriched agriculture-return flows in the unconfined 180-foot aquifer in the central valley; (3) young water recharge (6 to 20 years) fi-om the Salinas River, which is enriched in 18O and D relative to GMWL, occurs in the southern basin; and (4) travel time of >10,000 years (14C = 21.3 PMC) in the deep 400-foot aquifer in the northern area of the valley, indicating pristine slow recharge. We identified several different end-member saline components with distinguishable chemical and isotopic fingerprints: (1) agriculture return flow in the perched aquifer (e.g., high NO3 and SO4, low 87Sr/86Sr 0.7082, δ11B = 19 per mille); (2) salt-water intrusion in the northern basin (e.g., low Na/Cl, marine Br/Cl, high Ca/Mg, δ11B = 17 to 38 per mille, 87Sr/86Sr = 0.7088 to 0.7096; (3) non-marine saline water in the southern part of the valley (e.g., high SO4, high Na/Cl, δ11B = 24 to 30 per mille, 87Sr/86Sr = 0.70852). The geochemical and isotopic fingerprints of the different water sources enables us to delineate the impact of these sources in different areas of the valley as well as to evaluate the origin of the saline, Sod-enriched plume, that is located north of Salinas City Our data

  19. Dry extraction of 14C02 and 14C0 from Antarctic ice

    NARCIS (Netherlands)

    Roijen, J.J. van; Bintanja, R.; Borg, R. van den; Broeke, M.R. van den; Jong, A.F.M. de; Oerlemans, J.

    1994-01-01

    A dry extraction method was used to obtain trapped CO, of 2-5 kg ice samples from a blue ice zone in East Antarctica. In situ produced 14C was also extracted in 14C0, and 14C0 concentrations at a ratio of 3.4 f 0.9. Correction of trapped 14C0, from in situ resulted in ice dates in the range 5-15 ka.

  20. Direct measurements of small 14C samples after oxidation in quartz tubes

    International Nuclear Information System (INIS)

    Small 14C samples gain importance in environmental research and for dating purposes. However, throughput of such samples is limited by the preparation of graphite targets for accelerator mass spectrometry (AMS) measurements. In our approach, oxidation of samples with copper oxide in quartz tubes was applied to form CO2 which was measured directly with the gas ion source of the small AMS facility MICADAS. The presented method was designed to meet the requirements for fast and easy handling of small samples (- currents.

  1. Dating burial practices and architecture at Lepenski Vir

    OpenAIRE

    Bonsall, Clive; Radovanović, Ivana; Roksandic, Mirjana; Cook, Gordon T.; Higham, Thomas; Pickard, Catriona

    2008-01-01

    Previous attempts to establish a chronology for Lepenski Vir using three different methods (stratigraphy, radiometric 14C dating of bulk charcoal samples, and AMS 14C dating of human bone collagen) produced inconsistent results. Discrepancies between the human bone and charcoal ages were found to result from a reservoir effect in the bones of people who ate significant quantities of Danube fish. When a reservoir ‘correction’ is applied, the human bone 14C dates are consistent with the charcoa...

  2. Reconnaissance 14C Dating and the Evaluation of Mg/Li as a Temperature Proxy in Bamboo Corals from the California Margin

    Science.gov (United States)

    Freiberger, M. M.; LaVigne, M.; Miller, H.; Hill, T. M.; McNichol, A. P.; Lardie Gaylord, M.

    2015-12-01

    In the face of anthropogenically induced climate changes, it is becoming increasingly important to develop high-resolution paleoceanographic records that may elucidate how ocean conditions may shift in coming decades. Recently, bamboo corals (gorgonian octocorals) have been proposed as archives of intermediate ocean conditions. This study used 'reconnaissance' radiocarbon analysis to identify the nuclear bomb 14C spike in the proteinaceous nodes of bamboo corals and to quantify radial growth rates and ages of corals spanning the eastern Pacific oxygen minimum zone (OMZ) (790-2055 m). Preliminary data suggest that these corals exhibit a wide range of growth rates (9.4-350 μm/yr) that are non-linear over time and decrease with coral age and depth. Records of Mg/Li were investigated in these corals, given that previous studies have demonstrated positive correlations between Mg/Li and temperature in benthic foraminifera and surface and deep-sea aragonitic corals, with a reduced influence of vital effects over Mg/Ca. Intracoral reproducibility observed for replicate Mg/Li timeseries within each sample (p=0.6±0.2, n=6) and strong correlations between Mg/Ca and Li/Ca (0.9±0.1, n=6) indicate similar environmental or biological drivers of Mg and Li incorporation in bamboo corals. Given the strong positive correlations between Mg/Li and water temperature across a depth transect (r2=0.87, n=6), increasing Mg/Li observed over the growth history of each of the corals more likely reflects declining growth rates resulting in decreased Li incorporation over time rather than cooling of California Margin intermediate waters. Reductions in growth rate over the lifespan of each coral (~100+ years) may be a function of natural coral growth patterns or changes in carbonate chemistry, oxygen, or food supply in a sensitive OMZ coral ecosystem.

  3. Refining 14C dating of bone >30,000 BP : establishing an accurate chronology for the Middle to Upper Palaeolithic transition in France.

    NARCIS (Netherlands)

    Talamo, Sahra

    2012-01-01

    This thesis aims to improve the chronology of the transition from the Middle to Upper Palaeolithic in France through the radiocarbon dating of bone collagen samples. This requires accurate calibration of the radiocarbon time scale for this time interval, reliable extraction of collagen from prehisto

  4. Applications of 10Be, 14C, and 32Si to geological questions

    International Nuclear Information System (INIS)

    Radiometric dating is regarded as fundamental to any modern timescale calibration. In terms of available isotopic dating and tracing tools in environmental sciences, the cosmogenic isotopes stand out because of their application in the range from the very recent up to the middle Miocene. At IGNS, three long-lived cosmogenic isotopes can be measured. 14C (half life=5730 years) and 10Be (half-life = 1.5 Ma) are measured by Accelerator Mass Spectrometry (AMS) of 10Be/9Be and 14C/13C ratios, while 32Si (half-life > 140 years) is measured by radioactive decay counting of its daughter-product 32P. The main advantage of AMS over decay counting is the relatively small amount of sample material needed. AMS has made it feasible to measure ultra-low concentrations of long-lived isotopes such as 10Be. (author)

  5. Reviewing the Mid-First Millennium BC {sup 14}C 'warp' using {sup 14}C/bristlecone pine data

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.E., E-mail: retaylor@ucr.edu [Department of Anthropology, University of California, Riverside, Riverside, CA (United States); Cotsen Institute of Archaeology, University of California, Los Angeles, CA (United States); Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory, University of California, Irvine, CA (United States); Southon, John [Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory, University of California, Irvine, CA (United States)

    2013-01-15

    AMS-based {sup 14}C measurements have been obtained on 53 dendrochronologically-dated Bristlecone pine (Pinus longaeva) wood samples in decadal increments spanning 2300-2750 cal BP with particular interest focused on the decades centered on 2405 cal BP and 2625 cal BP. In general, there is overall agreement with the current IntCal04/09 consensus calibration curve for this period. For the 2400-2410 cal BP interval, our Bristlecone-based {sup 14}C value is consistent with the {sup 14}C value obtained by Belfast on Irish oak for that decade but not on German oak values obtained by Seattle. Our {sup 14}C value for the 2620-2630 cal BP interval is consistent with the German oak (Heidelberg)-based {sup 14}C decadal value. The {sup 10}Be-based reconstruction of {sup 14}C variations over the 2620-2630 cal BP interval also supports the Heidelberg data although clearly additional clarifications are required before the current tree ring-based {sup 14}C and ice core-based {sup 10}Be data for this interval can be accurately interpreted and valid inferences obtained.

  6. Desert Habitation History by 14C Dating of Soil Layers in Rural Building Structures (Negev, Israel): Preliminary Results from Horvat Haluqim

    OpenAIRE

    Bruins, Hendrik J.; van der Plicht, Johannes; Haiman, Mordechai

    2012-01-01

    Traditional archaeological approaches in the central Negev Desert used to employ excavation techniques in post-prehistoric periods in which stratigraphy is based on architecture, while material culture forms the basis for dating assessment and chronology. Such an approach was understandable, as it focused on the most visible remains of past human habitation. However, the detailed habitation record is in the soil rather than in the walls. Moreover, ceramics and stone tools in desert cultures o...

  7. Ice-wedge ice near Vorkuta town: the first for north of Europe 14C-dated oxygen isotope and deuterium plots

    International Nuclear Information System (INIS)

    The age of polygonal peat occurring near Vorkuta was identified by the method of radioactive carbon dating. It was ascertained that accretion of the peat enclosing ice-wedge took place in the period of the holocene optimum, i.e. from 9.2 to 5.5 thous. years ago. Relying on data on isotope-oxygen and deuterium composition of the ice wedges, the conclusion was made about similarity of the winter temperature values in contemporary period and in the first half of the holocene optimum

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

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

  9. Datação da fração humina da matéria orgânica do solo e sua comparação com idades 14C de carvões fósseis Dating of the humin fraction of soil organic matter and its comparison with 14C ages of fossil charcoal

    Directory of Open Access Journals (Sweden)

    Susy Eli Marques Gouveia

    1999-12-01

    Full Text Available The radiocarbon dating of the soil organic matter (SOM is a polemic subject, due mainly to the complexity of the formation of the soils and to the variable contamination from several sources. Soil samples from 4 different Brazilian localities were submitted to physical and chemical pre-treatment for the extraction of humin fraction, which is the most stable organic compound and theoretically the oldest and representative of the age of the SOM. The radiocarbon dating obtained from the total SOM and their humin fractions are compared to the 14C ages from buried charcoals at similar depths. The radiocarbon ages obtained from such charcoals are, in most of the cases, concordant within the experimental errors of those obtained on humin fractions, or are in average 10% higher, with one exception. Thus, the ages on humin fractions could be assumed as the minimum ages for the associated soils, while the results obtained on total SOM, even at depths until 200 cm, exhibit pronounced contamination effect by modern carbon, rejuvenating their ages.

  10. Comparison of Varve and 14C Chronologies from Steel Lake, Minnesota, USA

    Energy Technology Data Exchange (ETDEWEB)

    Tian, J; Brown, T A; Hu, F S

    2004-12-29

    Annually laminated sediments (varves) offer an effective means of acquiring high-quality paleoenvironmental records. However, the strength of a varve chronology can be compromised by a number of factors, such as missing varves, ambiguous laminations, and human counting error. We assess the quality of a varve chronology for the last three millennia from Steel Lake, Minnesota, through comparisons with nine AMS {sup 14}C dates on terrestrial plant macrofossils from the same core. These comparisons revealed an overall 8.4% discrepancy, primarily because of missing/uncountable varves within two stratigraphic intervals characterized by low carbonate concentrations and obscure laminations. Application of appropriate correction factors to these two intervals results in excellent agreement between the varve and {sup 14}C chronologies. These results, together with other varve studies, demonstrate that an independent age-determination method, such as {sup 14}C dating, is usually necessary to verify, and potentially correct, varve chronologies.

  11. Instrumental developments at the IBA-AMS dating facility at the University of Lecce

    International Nuclear Information System (INIS)

    The accelerator mass spectrometry (AMS) radiocarbon dating facility at the University of Lecce, Italy is now fully operational and in the first year of operation more than 500 samples both organic and inorganic have been measured for applications in archaeology, history of art, geology and environmental sciences. The experimental capabilities of the facility have been recently significantly improved by the installation of an in vacuum and in air ion beam analysis (IBA) beam line. Investigations are routinely carried out in material science and cultural heritage diagnostics

  12. Progress in AMS measurement of natural {sup 32}Si for glacier ice dating

    Energy Technology Data Exchange (ETDEWEB)

    Morgenstern, Uwe, E-mail: u.morgenstern@gns.cri.n [GNS Science, National Isotope Centre, P.O. Box 30368, Avalon, Lower Hutt (New Zealand); Keith Fifield, L.; Tims, Stephen G. [Department of Nuclear Physics, RSPhysSE, The Australian National University, ACT 0200 (Australia); Ditchburn, Robert G. [GNS Science, National Isotope Centre, P.O. Box 30368, Avalon, Lower Hutt (New Zealand)

    2010-04-15

    AMS measurement of {sup 32}Si can allow for ice core dating over the last thousand years. Technique developments are reported. Necessary negative-ion yields of 20-30% can now be consistently achieved, and permit an overall efficiency from ice sample to detector of approx1%. A {sup 30}Si-spike technique has overcome the problem of extremely low intrinsic silicon concentration, with the added benefit of allowing determination of ppb-level silicon via isotope dilution. Improvements have also been made to the ionization detector in the gas-filled magnet that separates the accelerated {sup 32}Si ions from the intense flux of {sup 32}S ions. Preliminary {sup 32}Si AMS results of snow and ice samples from Mt. Cook National Park, New Zealand, are reproducible, and with {sup 32}Si concentrations 1.2-7.2 mBq/m{sup 3} comparable to results from mid-latitude snow samples measured previously via the radiometric technique, demonstrating the feasibility of the method. With these developments, the potential of {sup 32}Si as ice core dating tool is close to being realized, and attempts to determine chronologies for both alpine and Antarctic glaciers are underway.

  13. Tritium AMS for biomedical applications

    International Nuclear Information System (INIS)

    The authors are developing 3H accelerator mass spectrometry (AMS) at LLNL for work in the biological sciences. Their group has applied 14C AMS to a variety of problems (such as low-level dosimetry of genotoxic materials) and the development and demonstration of 3H AMS would greatly complement these studies. In conjunction with their present AMS capacity, the ability to perform 3H AMS measurements at equivalent sensitivities will allow them to perform unique double labeling experiments in which they learn the fate, distribution, and metabolism of separate fractions of xenobiotics and biologicals. Also, the large number of commercially available 3H-tagged compounds will allow them to perform experiments using compounds that are simply unavailable in 14C-tagged form. The authors anticipate being able to measure 3H/1H concentrations as low as 1 part in 1014 from sample masses as low as 2 μgs. Progress to date and future plans are discussed

  14. Some interesting and exotic applications of carbon-14 dating by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    There are many applications of 14C dating and other measurements using accelerator mass spectrometry (AMS). In particular, applications to dating of archaeological samples and interesting artifacts are discussed. Other applications, such as to extraterrestrial materials such as lunar samples and meteorites show the broad range of topics that can be addressed with 14C studies.

  15. Prospects for ''iodine-129 dating'' of marine organic matter using AMS

    International Nuclear Information System (INIS)

    Natural levels of iodine 129 have been overwhelmed by a build-up of ''new'' iodine-129, a product of our nuclear age. Much of this new iodine-129 has entered the ocean and is now found in its upper layers. During primary production, marine organic matter incorporates iodine, which then moves through the food chain. The 129I/127I ratio in marine organics therefore represents the value found in the ocean's photic zone when the organic matter formed. Because the 129I/127I ratio in any well-mixed marine basin has increased rapidly since the advent of the nuclear age, establishing the build up pattern of 129I in that basin's surface waters would allow us to ''date'' the time of formation of any organics formed there, provided that we can obtain an adequate amount of iodine from samples. Measurement of this ratio requires the use of AMS. (orig.)

  16. Peat record reflecting Holocene climatic change in the Zoige Plateau and AMS radiocarbon dating

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Through the use of reliable AMS dating of high resolution (15-30 years) peat and the establishment of monsoon climate proxies sequence, we have been able to recognize several cold, dry events in the Tibetan Plateau during the Holocene. The more obvious ones occurred around 12800, 11300, 10200, 9580, 8900, 6400, 4400, 3700, 2800 and 1500 cal. aBP. These events correlate well with both ice rafting events recorded in high latitude North Atlantic Ocean sediment cores and cooling events in the low latitude SST. Spectral analysis indicates high frequency climate variation on centennial-millennial time scale during the Holocene. This further reflects Holocene climate instability and the existence of centennial-millenium scale rhythm in mid latitude areas as well.

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

    Science.gov (United States)

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

    2014-12-01

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

  18. The Sharp Rise of Δ14C ca. 800 cal BC : Possible causes, related climatic teleconnections and the impact on human environments

    NARCIS (Netherlands)

    Geel, Bas van; Plicht, Johannes van der; Kilian, M.R.; Klaver, E.R.; Kouwenberg, J.H.M.; Renssen, H.; Reynaud-Farrera, I.; Waterbolk, H.T.

    1998-01-01

    In this study we report on accelerator mass spectrometry (AMS) wiggle-match dating of selected macrofossils from organic deposits ca. 800 cal BC (ca. 2650 BP). Based on paleological, archaeological and geological evidence, we found that the sharp rise of atmospheric 14C between 850 and 760 cal BC co

  19. Uptake of [14C]triadimenol via grain and root after seed treatment of winter barley with a flowable seed dressing: Influence of soil moisture and sowing date on the distribution of radioactivity and active ingredient content in plant and soil

    International Nuclear Information System (INIS)

    Winter barley seed of the 'Vogelsander Gold' variety was shown in a total of 7 lysimeters after seed treatment with [benzene ring-U-14C]triadimenol in the formulation as [14C]Baytan 075 FS and [14C]Baytan 25 DS at an early (September) and a late date (October). After both dates of sowing, the FS-treated winter barley developed under 3 different soil moisture conditions. The radioactivity and active ingredient contents in plants and soil were recorded until tillering as a function of low, high and natural precipitation after sowing. Details on the uptake of radioactivity via grain and roots were quantitatively and qualitatively studied in two further lysimeters, a pot experiment as well as experiments in the growth chamber. The results are presented and discussed in detail. (orig./MG)

  20. Radiocarbon dating of a Japanese ancient document 'Minamoto no Yoritomo Sodehan Migyosho' by AMS

    International Nuclear Information System (INIS)

    In this study, radiocarbon age of a Japanese ancient document 'Minamoto no Yoritomo Sodehan Migyosho' was measured by AMS. The purpose of this study is to judge whether the document is genuine or not. The document descended to the Matsugi family which had controlled the craftsmen of metal casting. The document has a description of the written age, AD1189. The content of the document is about the formal recognition of their authority over the craftsmen by Minamoto no Yoritomo who established the first military government in AD1192. This document is written on a slightly-blackish-paper sheet called Shukushi. Shukushi paper sheets had been commonly used for the official documents of the Emperor. Therefore, if the document was really issued by Minamoto no Yoritomo, it can be a sole example as the document of warrior class among the extant Shukushi paper. The paleographical views, however, suggested that the document may be a counterfeit written in several centuries later. Japanese paper fragment is a suitable sample for radiocarbon dating because there is little discrepancy between the calibrated radiocarbon age and the written age. The calibrated radiocarbon age of 'Minamoto no Yoritomo Sodehan Migyosho' indicated the 16th century or the first half of the 17th century. This age corresponds to the period when the ancestor of Matsugi family appeared in Japanese history. This result shows that the document was forged in the Warring State Period for the legitimacy of their control over the craftsmen. The Shukusi used for the counterfeit document of warrior class is the outcome of the forger's misunderstanding that Shukushi paper should be used for the important documents.

  1. 14C accelerator mass spectrometry - applications in archaeology, biomedicine and in the atmospheric sciences

    International Nuclear Information System (INIS)

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

  2. RICH - A new AMS facility at the Royal Institute for Cultural Heritage, Brussels, Belgium

    Science.gov (United States)

    Boudin, Mathieu; Van Strydonck, Mark; van den Brande, Tess; Synal, Hans-Arno; Wacker, Luckas

    2015-10-01

    Since 1989 the radiocarbon dating lab has their own graphitization system for 14C AMS dating but RICH (Royal Institute for Cultural Heritage) did not possess their own AMS and measurements were carried out in collaboration with other AMS facilities. In April 2013 the Micadas (Mini Carbon Dating System) AMS was installed at RICH in Brussels and after 1.5 year operation the high stability and performance of the Micadas can be demonstrated by repeated analyses of primary standard OXA II and secondary standards. Results of unknown samples measured on the RICH-Micadas and on other AMS systems are in good agreement.

  3. {sup 14}C in human diet in three Spanish locations; {sup 14}C en dieta humana en tres localizaciones espanolas

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Martinez, I.; Santos Arevalo, F. J.; Manjon, G.; Garcia-Tenorio, R.

    2011-07-01

    {sup 14}C reach humans via the diet. In this study we present the results of diet samples from three locations type Spanish, Seville, Caceres and Tenerife. These diets are collected quarterly and historical dates back to early 2008.

  4. Synthesis of barbituric acid-2 14C and alloxan-2 14C from urea 14C

    International Nuclear Information System (INIS)

    Urea 14C and ethyl malonate have given rise to barbituric acid with a 93 per cent yield. The latter has been converted into its benzylidene derivative with a 81 per cent yield. Oxidation of the latter, by chromic oxide in anhydrous acetic acid provided alloxan-2 14C with 60 per cent yield. Purity of the compounds has been checked by paper chromatography. (author)

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2011-01-01

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

  7. Accelerator mass spectrometry analysis of 14C-oxaliplatin concentrations in biological samples and 14C contents in biological samples and antineoplastic agents

    Science.gov (United States)

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

    2015-10-01

    Accelerator mass spectrometry (AMS) is expected to play an important role in microdose trials. In this study, we measured the 14C concentration in 14C-oxaliplatin-spiked serum, urine and supernatant of fecal homogenate samples in our Yamagata University (YU) - AMS system. The calibration curves of 14C concentration in serum, urine and supernatant of fecal homogenate were linear (the correlation coefficients were ⩾0.9893), and the precision and accuracy was within the acceptance criteria. To examine a 14C content of water in three vacuum blood collection tubes and a syringe were measured. 14C was not detected from water in these devices. The mean 14C content in urine samples of 6 healthy Japanese volunteers was 0.144 dpm/mL, and the intra-day fluctuation of 14C content in urine from a volunteer was little. The antineoplastic agents are administered to the patients in combination. Then, 14C contents of the antineoplastic agents were quantitated. 14C contents were different among 10 antineoplastic agents; 14C contents of paclitaxel injection and docetaxel hydrate injection were higher than those of the other injections. These results indicate that our quantitation method using YU-AMS system is suited for microdosing studies and that measurement of baseline and co-administered drugs might be necessary for the studies in low concentrations.

  8. AMS radiocarbon dating of medieval textile relics: The frocks and the pillow of St. Francis of Assisi

    International Nuclear Information System (INIS)

    Since natural textiles usually originate from short-lived organisms, they can represent a useful material to date samples from historical periods with a good accuracy. In this work, we present a set of radiocarbon measurements on medieval textile relics: two woollen habits and a pillow traditionally associated with St. Francis of Assisi, the saint patron of Italy. The strategy in choosing samples for radiocarbon dating is first discussed and the procedures for measurements - performed at the 3 MV Tandetron accelerator of Laboratorio di Tecniche Nucleari per i Beni Culturali (LABEC), Florence - are described; AMS results for the two frocks showed that only one of them, presently kept in the church of St. Francis in Cortona, is compatible with the Saint's period of life, as is the pillow also kept in Cortona. Another frock attributed to St. Francis appears to date from at least 80 years after his death. However, the goal of these measurements was not a bare authentication/disconfirmation of the relics; they just represent an example of how scientific analysis can integrate with humanistic studies. Indeed, AMS results, combined with a thorough analysis of the textiles typologies, confirmed the historical hypotheses based on documentary studies and on tradition. The overall conclusions contributed to the decisions taken for conservation, and have as a whole enhanced the religious importance of the relics

  9. A Multi-Isotope (B, Sr, O, H, C) and Age Dating (3H-3He, 14C) Study of Ground Water From Salinas Valley, California: Hydrochemistry, Dynamics, and Contamination Processes

    Energy Technology Data Exchange (ETDEWEB)

    Vengosh, A; Gill, J; Davisson, M L; Hudson, B G

    2001-08-01

    The chemical and isotopic ({sup 11}B/{sup 10}B, {sup 87}Sr/{sup 86}Sr, {sup 18}O/{sup 16}O, {sup 2}H/H, {sup 13}C/{sup 12}C, {sup 14}C, {sup 3}He/{sup 3}H) compositions of groundwater from the upper aquifer system of the Salinas Valley in coastal central California were investigated in order to delineate the origin and processes of groundwater contamination in this complex system. The Salinas Valley has a relatively deep, confined ''400-foot'' aquifer, overlain by a ''180-foot'' aquifer, and a shallower perched aquifer, all made up of alluvial sand, gravel, and clay deposits. Groundwater from the aquifers have different {sup 14}C ages; fossil ({sup 14}C = 21.3 pmc) for the 400-foot, and modern ({sup 14}C = 72.2 to 98.2 pmc) for the 180-foot. Fresh groundwater in all aquifers is recharged naturally and artificially and through the Salinas River. The two modes of recharge can be distinguished chemically. We identified several different saline components with distinguishable chemical and isotopic fingerprints. (1) Salt-water intrusion in the northern basin has Cl concentrations up to 1700 mg/l, a Na/Cl ratio seawater, {delta}{sup 11}B between +17 and +38 per mil, and {sup 87}Sr/{sup 86}Sr between 0.7088 and 0.7096. Excess dissolved Ca, relative to the expected concentration for simple dilution of seawater, correlates with {sup 87}Sr/{sup 86}Sr ratios, suggesting base exchange reaction with clay minerals. (2) Agriculture return flow is high in NO{sub 3} and SO{sub 4}, with a {sup 87}Sr/{sup 86}Sr = 0.7082, {delta}{sup 11}B = 19 per mil; and {delta}{sup 13}C between -23 and -17 per mil. The {sup 3}H-{sup 3}He ages (5-17 years) and {sup 14}C data suggest vertical infiltration rates of irrigation water of 3 to 10 m/yr. (3) Non-marine saline water in the southern part of the valley has high TDS up to 3800 mg/l, high SO{sub 4}, Na/Cl ratio >1, {delta}{sup 11}B between +24 and +30 per

  10. A high resolution method for 14C analysis of a coral from South China Sea: Implication for "AD 775" 14C event

    Science.gov (United States)

    Ding, Ping; Shen, Chengde; Yi, Weixi; Wang, Ning; Ding, Xingfang; Liu, Kexin; Fu, Dongpo; Liu, Weiguo; Liu, Yi

    2015-10-01

    A pre-heating method that improves the background and precision of 14C dating significantly was applied for fossil coral dating with high resolution in our lab in Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (GIGCAS). The reaction tube is heated under 300 °C in a vacuum line before it is used for graphitization. The method can reduce the contamination absorbed in TiH2, Zn and Fe power placed in the graphitization tube. With the pre-heating and average drilling method, bi-weekly resolution 14C dating in a fossil coral is carried out to investigate the "AD 775 14C spike event". Different from the tree ring 14C archives with the 14C spike of ∼15‰ (Δ14C), the 14C spike in the coral shows an abrupt peak of 45‰ and two smaller spikes of Δ14C > 20‰ in half a year in AD 776. And then, the 14C content in coral decreases gradually in AD 777. The peak time of the 14C spike event likely occurs in the summer of AD 776 according to the δ18O variation in coral. High-resolution dating of 14C in coral provides not only a more detail process of the event than that from tree rings, but also the first report of the event from sea ecosystem. Both of them suggest an extraterrestrial origin of the event cause.

  11. AMS exposure dating: evolution of river valley profiles across Himalayas during late Quaternary-Holocene

    International Nuclear Information System (INIS)

    River valley profile is one geomorphic feature, which contain relict landforms inherited from past periods with changing intensities of tectonic and climatic parameters. This aspect has been a subject of current research interest, using exposure dating technique. The results of some recent studies from major river valleys across Himalayas are being discussed

  12. In situ determination of 241Am on Enewetak Atoll. Date of survey: July 1977-December 1979

    International Nuclear Information System (INIS)

    An in situ gamma ray spectrometer system was operated at Enewetak Atoll from July 1977 to December 1979 in support of the Enewetak Cleanup Project. The system employed a high purity germanium planar detector suspended at a height of 7.4 m above ground. Conversion factors were established to relate measured photopeak count rate data to source concentration in the soil. Data obtained for 241Am, together with plutonium-to-americium ratios obtained from soil sample analyses, were used to establish area-averaged surface (0 to 3 cm) transuranic concentration values. In areas which exceeded cleanup criteria, measurements were made in an iterative fashion to guide soil removal until levels were reduced below the cleanup criteria. Final measurements made after soil removal had been completed were used to document remaining surface transuranic concentration values and to establish external exposure rate levels due to 137Cs and 60Co

  13. First direct dating of Late Pleistocene ice-wedges by AMS

    OpenAIRE

    Vasil'chuk, YK; Van Der Plicht, J.; Jungner, H.; Sonninen, E; Vasil'chuk, AC; Vasil'chuk, Yurij K.; Vasil'chuk, Alla C.

    2000-01-01

    We present the first direct dating by C-14-accelerator mass spectrometry of three Late Pleistocene syngenetic ice-wedges from the Seyaha cross-section. They are representative of permafrost with multistage ice-wedges from the North of Western Siberia. The most important result is the clear vertical age stratification of the ice, i.e. the old ice is located beneath the young. This shows that a timescale can be assigned to these ice-wedges penetrating down into the permafrost. The age of the ic...

  14. The Sharp Rise of Δ14C ca. 800 cal BC: Possible causes, related climatic teleconnections and the impact on human environments

    OpenAIRE

    Van Geel, Bas; van der Plicht, Johannes; Kilian, M.R.; Klaver, E.R.; Kouwenberg, J.H.M.; H. Renssen; Reynaud-Farrera, I.; Waterbolk, H.T.

    1998-01-01

    In this study we report on accelerator mass spectrometry (AMS) wiggle-match dating of selected macrofossils from organic deposits ca. 800 cal BC (ca. 2650 BP). Based on paleological, archaeological and geological evidence, we found that the sharp rise of atmospheric 14C between 850 and 760 cal BC corresponds to the following related phenomena: 1. In European raised bog deposits, the changing spectrum of peat forming mosses and a sharp decline in decomposition of the peat indicate a sudden cha...

  15. 14C ages for the ejecta from Kutcharo and Mashu calderas, eastern Hokkaido, Japan

    International Nuclear Information System (INIS)

    Eruption ages of the ejecta from Kutcharo and Mashu calderas were systematically determined by 14C dating. 16 charred samples were newly obtained from the Mashu and Nakashumbetsu Tephra Formations around the calderas and dated by AMS and β-counting methods. Examined units are Ma-d, Ma-e, Ma-f, Ma-j, Ma-k, Ma-l and Ml-a in the Mashu ejecta and 6 Nakashumbetsu tephra layers including Kutcharo Pumice Flow Deposit I (KpI), which is the youngest caldera-forming product from Kutcharo caldera. Results of the 14C dating range from 3,660 ±40 yBP to 36,080±1,300 yBP, and are consistent with the tephrostratigraphy. Calendar age for KpI was newly calculated at almost 40 ka and this age shows there was about 70,000 years recurrence interval between KpI and KpIV caldera-forming eruptions. Mashu caldera has appeared on the eastern part of Kutcharo caldera immediately after the KpI eruption, and calendar age for its main caldera-forming eruption were determined at ca. BC 5,600. (author)

  16. Thermophilic Anaerobic Biodegradation of [14C]Lignin, [14C]Cellulose, and [14C]Lignocellulose Preparations

    OpenAIRE

    Benner, Ronald; Hodson, Robert E.

    1985-01-01

    Thermophilic (55°C) anaerobic enrichment cultures were incubated with [14C-lignin]lignocellulose, [14C-polysaccharide]lignocellulose, and kraft [14C]lignin prepared from slash pine, Pinus elliottii, and 14C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were ...

  17. Radiocarbon dating of late pleistocene marine shells from the southern North Sea

    NARCIS (Netherlands)

    Busschers, F.S.; Wesselingh, F.P.; Kars, R.H.; Versluijs-Helder, M.; Wallinga, J.; Bosch, J.H.A.; Timmner, J.; Nierop, K.G.J.; Meijer, T.; Bunnik, F.P.M.; Wolf, H. de

    2014-01-01

    This article presents a set of Late Pleistocene marine mollusk radiocarbon (AMS) age estimates of 30-50 14C kyr BP, whereas a MIS5 age (>75 ka) is indicated by quartz and feldspar OSL dating, biostratigraphy, U-Th dating, and age-depth relationships with sea level. These results indicate that the 14

  18. Benzene Synthesis for 14C Measurements and Evaluation of Uncertainty in Mollusk Shells

    International Nuclear Information System (INIS)

    This work describes the method and Instrumentation used by Environmental Isotopes laboratory of the CIEMAT Analytical Chemistry Laboratory (DIAE) for the synthesis of benzene from carbonates of mollusk shells and the liquid scintillation counting of 14C for radiocarbon dating in these samples. The usefulness of mollusk shells for 14C dating are considered. (Author) 15 refs

  19. Effects of sample mass and macrofossil type on radiocarbon dating of arctic and boreal lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Oswald, W W; Anderson, P M; Brown, T A; Brubaker, L B; Hu, F S; Lozhkin, A V; Tinner, W; Kaltenrieder, P

    2006-05-29

    Dating lake sediments by accelerator mass spectrometry (AMS) {sup 14}C analysis of plant macrofossils overcomes one of the main problems associated with dating bulk sediment samples, the presence of old organic matter. Even so, many AMS dates from arctic and boreal sites appear to misrepresent the age of the sediment. To understand the nature of these apparent dating anomalies better, we conducted a series of {sup 14}C dating experiments using samples from Alaskan and Siberian lake-sediment cores. First, to test whether our analytical procedures introduced a sample-mass bias, we obtained {sup 14}C dates for different-sized pieces of single woody macrofossils. In these sample-mass experiments, sized statistically equivalent ages were found for samples as small as 0.05 mg C. Second, to assess whether macrofossil type influenced dating results, we conducted sample-type experiments in which {sup 14}C dates were obtained for different macrofossil types sieved from the same depth in the sediment. We dated materials from multiple levels in sediment cores from Upper Capsule Lake (North Slope, northern Alaska) and Grizzly Lake (Copper River Basin, southern Alaska), and from single depths in other records from northern Alaska. In several of the experiments there were significant discrepancies between dates for different plant tissues, and in most cases wood and charcoal were older than other macrofossil types, usually by several hundred years. This pattern suggests that {sup 14}C dates for woody macrofossils may misrepresent the age of the sediment by centuries, perhaps due to their longer terrestrial residence time and the potential in-built age of long-lived plants. This study identifies why some {sup 14}C dates appear to be inconsistent with the overall age-depth trend of a lake-sediment record, and it may guide the selection of {sup 14}C samples in future studies.

  20. 41 CFR 301-11.10 - Am I required to record departure/arrival dates and times on my travel claim?

    Science.gov (United States)

    2010-07-01

    ... departure/arrival dates and times on my travel claim? 301-11.10 Section 301-11.10 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES ALLOWABLE TRAVEL EXPENSES 11-PER DIEM EXPENSES General Rules § 301-11.10 Am I required to record...

  1. An update on in situ cosmogenic 14C analysis at ETH Zürich

    International Nuclear Information System (INIS)

    We present the improved performance of the modified in situ cosmogenic 14C extraction system at ETH Zürich. Samples are now processed faster (2 days in total) and are measured with a high analytical precision of usually 414C atoms. Analyses of samples from a ∼300 year old rock avalanche prove that we can successfully apply in situ14C exposure dating to very young surfaces. Additionally, we present a modified calculation scheme for in situ14C concentrations which differs from that used for conventional radiocarbon dating. This new approach explicitly accounts for the characteristics of in situ14C production.

  2. Synthesis of carbonyl-14C labelled 'acetochlor'

    International Nuclear Information System (INIS)

    Carbonyl-14C labelled 'acetochlor' (2-chloro-N-ethoxymethyl-N-(2-ethyl-6-methylphenyl)acetamide) was prepared by chlorination of acetic-1-14C acid obtained from barium radiocarbonate to monochloroacetic-1-14C acid which was further chlorinated to monochloroacetyl-1-14C chloride. The addition reaction of this latter with 2-ethyl-6-methylene aniline gave a chloromethyl derivative the ethanolysis of which resulted in 'acetochlor' labelled in its carbonyl carbon. The overall radiochemical yield is 51%. (author)

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

    International Nuclear Information System (INIS)

    To clarify the behavior of 14C in terrestrial ecosystems, 14C abundance in soil respiration was evaluated in an urban forest with a new method involving a closed chamber technique and 14C measurement by accelerator mass spectrometry (AMS). Soil respiration had a higher Δ14C than the contemporary atmosphere. This indicates that a significant portion of soil respiration is derived from the decomposition of soil organic matter enriched in 14C by atmospheric nuclear weapons tests, with a notable time lag between atmospheric 14C addition and re-emission from soil. On the other hand, δ14C in soil respiration demonstrated that 14C abundance ratio itself in soil-respired CO2 is not always high compared with that in atmospheric CO2 because of the isotope fractionation during plant photosynthesis and microbial decomposition of soil organic matter. The Δ14C in soil respiration was slightly lower in August than in March, suggesting a relatively high contribution of plant root respiration and decomposition of newly accumulated and/or 14C-depleted soil organic matter to the total soil respiration in August

  4. Bomb pulse radiocarbon dating

    International Nuclear Information System (INIS)

    Modern forensic science has to deal not only with homicides and other traditional crimes but also with more global threats such as the smuggling of nuclear materials, clandestine production of weapons of mass destruction, stockpiling of illicit drugs by state controlled groups and war crimes. Forensic applications have always benefited from the use of advanced analytical tools that can characterize materials found at crime scenes. In this paper we will discuss the use of accelerator mass spectrometry (AMS) as an ultrasensitive tool for the crime laboratories of the third millennium. An important objective in forensic science is to order past events chronologically by analysing materials associated with criminal actions. Radiocarbon dating is known to the general public for its application to historical and prehistorical investigations. Examples of forensic significance include the assassination of the Inca Atahualpa by Francisco Pizarro in the early 1530s, the possible murder of the Tyrolean Ice Man (Oetzi) 5300 years ago and the analysis of the burial cloths allegedly associated with the crucifixion of Jesus Christ . Recent murders, including those associated with war crimes in the Balkans during the 1990s, can be studied using 14C bomb pulse dating. This method has other forensic applications, including investigation of frauds related to food and wine counterfeiting, dating of opium crops and dating of substances used in biological warfare. AMS extends the applicability of the radiocarbon method, allowing the analysis of 14C in submilligram organic samples. Specific molecular compounds extracted from bones, hair, skin and other carbon bearing substances of forensic significance can now be dated, enhancing the sensitivity and reliability of chronological determinations. AMS can also be used to analyse rare actinide isotopes released into the environment during the clandestine production of nuclear weapons or associated with the smuggling of nuclear materials. In

  5. Measurement of fecal 14C excretion

    International Nuclear Information System (INIS)

    Simultaneous measurements of fecal 14C and expired 14CO2 in the breath are necessary to evaluate patients with various ileal abnormalities and bile salt malabsorption. Following the oral ingestion of the labeled bile acid, glycine-[I-14C]cholic acid, detection of increased fecal 14C without abnormal expiration of 14CO2 identifies patients with ileal resection. This contrasts with the normal fecal 14C content and abnormal expired 14CO2 found in patients with bacterial overgrowth. Fecal 14C content was determined by utilizing Van Slyke combustion of the specimen and trapping the liberated 14CO2 with Scintisorb C. The method is simple, rapid, and accurate, and expands the diagnostic usefulness of the bile salt absorption test

  6. Synthesis of 14C labelled acrylic derivatives: diethyl [3-14C] methylidenemalonate and isobutyl [3-14C] cyanoacrylate

    International Nuclear Information System (INIS)

    Isobutyl [3-14C] cyanoacrylate and diethyl [3-14C] methylidenemalonate were synthesized by the intermediate of their protective Diels-Alder adduct with anthracene. These adducts were obtained in a one-pot procedure by Knoevenagel condensation of [14C] paraformaldehyde with isobutyl cyanoacetate and diethyl malonate respectively in the presence of a basic catalyst and anthracene. The adducts are stable crystalline compounds easily purified by recrystallization. The olefinic target compounds were obtained in high chemical and radiochemical purity (>99%) by thermolysis at 2200C in mineral oil in the presence of maleic anhydride. (author)

  7. Incorporation of 14C from [14C]phenylalanine into condensed tannin of sorghum grain

    International Nuclear Information System (INIS)

    A procedure is described for obtaining condensed tannin from sorghum [Sorghum bicolor (L.) Moench] seeds metabolically labeled from [14C]phenylalanine. The [14C]tannin should be useful in determining the metabolic fate of dietary condensed tannin

  8. Modelling 14C transfer in terrestrial environments in response to chronic and accidental 14C releases.

    OpenAIRE

    Le Dizès, S.

    2011-01-01

    Concern about the quantity of carbon-14 (14C) released for several decades from nuclear facilities has prompted several modelling approaches of 14C behaviour in the environment. The TOCATTA model aims at estimating 14C (and 3H) transfers in terrestrial ecosystems exposed to atmospheric 14C (and 3H) releases from nuclear facilities under normal operating or accidental conditions. The model belongs to the larger framework of the SYMBIOSE modelling and simulation platform that aims at assessing ...

  9. 14C-carbaryl residues in hazelnut.

    Science.gov (United States)

    Yücel, Ulkü; Ilim, Murat; Aslan, Nazife

    2006-01-01

    A hazelnut ocak (shrub growing form) in the field in Black Sea region of Turkey was treated with commercial carbaryl insecticide spiked with 14C-carbaryl. Three months later, the harvested hazelnuts were separated into husk, shell, and kernel components, then homogenized and analyzed. The total and unextractable (bound) 14C-residues were determined by combustion and the extractable 14C-residues were obtained by extracting the samples with methanol. Concentrated extracts were first analyzed by thin layer chromatography (TLC). The extracts were also subjected to a series of liquid-liquid extraction procedures for clean-up and the final extracts were analyzed by high performance liquid chromatography (HPLC). Crude hazelnut oil was also extracted with hexane and analyzed for total 14C-residue. A total of 1.3% of applied radioactivity was recovered from the total nut harvested, with 0.04%, 0.06%, and 1.2% present in shell, kernel, and husk, respectively. The results show that the inedible husk and shell contained 95.7% 14C, whereas the edible kernel contained 4.3% of the total 14C recovered. The terminal 14C-residue in hazelnut kernel and oil did not contain carbaryl and/or its metabolite naphthol. PMID:16785168

  10. Recent tree ring analyses at the ANTARES AMS centre

    International Nuclear Information System (INIS)

    A total of 48 annual tree rings (24 pairs) from 1952 to 1975 AD have been carefully split, milled and pretreated to alpha-cellulose, the most reliable component of wood for dating. Due to the small amount of material available in each ring, accelerator mass spectrometry (AMS) rather than the conventional method (radiometry) has been used for the determination of the 14C content in tree rings. Pretreated material was combusted to CO2 and then converted to graphite for the 14C measurement in ANTARES, the tandem accelerator at ANSTO. Excellent matching between our measured 14C tree-ring data and atmospheric 14C records at the same latitude has been found. Our data can therefore be used for: extension of atmospheric 14C bomb-pulse curves in tropical regions and the Southern Hemisphere back to the early stage of the nuclear age in the 1950's, for which few direct atmospheric records are available. This is needed to gain a better understanding of global carbon cycle and air-sea interactions; determination of the growth rate of trees in tropical regions (Murphy et al., 1997); and dating of modern organic material in tropical regions and the Southern Hemisphere (in combination with 14C atmospheric data)

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

    Energy Technology Data Exchange (ETDEWEB)

    Clifford, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Arjomand, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Duecker, S. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johnson, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schneider, P. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zulim, R. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bucholz, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vogel, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1999-03-25

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

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

    International Nuclear Information System (INIS)

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

  13. Using accelerator mass spectrometry for radiocarbon dating of textiles

    Energy Technology Data Exchange (ETDEWEB)

    Jull, A.J.T.

    1997-12-01

    Since 1981 we have operated an NSF Accelerator Mass Spectrometry (AMS) Facility at the University of Arizona. The AMS method allows us to use very small samples of carbon, <1 mg for radiocarbon dating in contrast to earlier counting techniques. This has opened a vast array of applications of radiocarbon dating that was difficult to do before AMS because of sample size limitations of decay counting. Some of the many applications of AMS include paleoclimatic studies, archaeological research and the age of first settlement of North America by man, dating of art works and artifacts, fall times and terrestrial residence ages of meteorites, production of {sup 14}C in lunar samples by galactic and solar cosmic rays, studies of in situ {sup 14}C produced by cosmic ray spallation in rocks and ice, and studies of {sup 14}C in groundwater dissolved inorganic carbon and dissolved organic carbon. At our laboratory, we have also successfully applied AMS {sup 14}C to dating of many types of textiles, including silks and linens, art works, documents and artifacts fabricated from wood, parchment, ivory, and bone. The results for many of these samples are often important in questions of the authenticity of these works of art and artifacts. Our studies have encompassed a wide range of art works ranging from the Dead Sea Scrolls, the Shroud of Turin, and the Chinese silk trade to the works of Raphael, Rembrandt, and Picasso. Recently, we also dated the Vinland Map, a controversial document that shows the eastern coast of North America apparently using information from Viking voyages.

  14. High sensitivity 14C-label studies in biology using accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Examples are provided of the use of a method to detect 14C-labelled biomolecules at ultratrace levels. The method is capable of 1% precision on samples of a few micrograms to milligrams that contain only the natural 14C content of the material examined. This precision corresponds to about 10-16 moles of 14C per mg of total carbon. The method is, therefore, several orders of magnitude more sensitive than traditional methods that depend on radioactive decay counting. This great sensitivity is based on using accelerator mass spectrometry (AMS) to count and detect the 14C. A new laboratory has been set up to prepare biological samples for AMS measurement. Examples of initial results obtained include measurement of a neurotoxin in brain tissue, a plant hormone in a kiwifruit vine, a carcinogen in liver and a dietary mutagen in blood. The potential applications of the method are outlined. (author). 4 refs., 5 tabs., 1 fig., 2 appendices

  15. AMS analyses at ANSTO

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, E.M. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Physics Division

    1998-03-01

    The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with {sup 14}C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for {sup 14}C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent`s indigenous Aboriginal peoples. (author)

  16. AMS analyses at ANSTO

    International Nuclear Information System (INIS)

    The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with 14C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for 14C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent's indigenous Aboriginal peoples. (author)

  17. Synthesis of [5-14C]-dodecane and [8-14C]-hexadecane

    International Nuclear Information System (INIS)

    [5-14C]-Dodecane and [8-14C]-hexadecane were synthesized starting with [1-14C]-octanoic acid. The carboxylic acid was reduced to 1-octanol, which was esterified to n-octyl p-toluenesulfonate. Following a Corey-House procedure, the sulfonate was either reacted with Li[Cu(butyl)2] to [5-14C]-dodecane (40% overall yield), or with Li[Cu(octyl)2] to [8-14C]-hexadecane (24% overall yield). The lithium di-alkyl cuprates were prepared from butyl lithium and n-octyl bromide, respectively. Preliminary experiments with non-labeled compounds using a Wittig reaction as chain extension step, turned out to be less favourable. The Corey-House route provides a simple method for the synthesis of specifically 14C-labeled alkanes from commercially available [1-14C]-carboxylic acids. (author)

  18. Synthesis of ethanol 14C-1

    International Nuclear Information System (INIS)

    The direct reduction by LiAlH4, of a suspension of anhydrous sodium acetate in tetra-hydro-furfuryl-oxy-tetra-hydro-pyran is described. This study has shown that the ethanol thus obtained is impure and that the yields are erratic. On the contrary the reduction of acetyl chloride 1-14C by LiAlH4, in 'diethyl carbitol' leads to ethanol 1-14C of satisfactory purity with a yield of about 71 percent. (author)

  19. 14C content in aerosols in Mexico City

    Science.gov (United States)

    Gómez, V.; Solís, C.; Chávez, E.; Andrade, E.; Ortiz, M. E.; Huerta, A.; Aragón, J.; Rodríguez-Ceja, M.; Martínez, M. A.; Ortiz, E.

    2016-03-01

    14C-AMS of total carbon was determined in aerosols (PM10 fraction), collected in Mexico City during two weeks from 21 November to 3 December 2012. Other tracers such as total carbon (TC), organic carbon (OC), elemental carbon (EC) and trace element contents were also determined. F14C values varied from 0.39 to 0.48 with an average of 0.43. These values are slightly lower than those previously obtained for PM2.5 in 2003 and 2006 and reflect a high contribution of fossil CO2 to the carbonaceous matter in aerosols from Mexico City. In contrast, from 2006 to 2012 PM10 increased; EC, Ca, Ti and Fe concentrations remained constant, while OC, TC and K concentrations decreased. The use of potassium as an indicator of biomass burning showed that this source was negligible during this campaign. Combined analytical approaches allowed us to distinguish temporal variations of anthropogenic and natural inputs to the F14C.

  20. The impact on archaeology of radiocarbon dating by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Radiocarbon dating by accelerator mass spectrometry (AMS) is based on direct determination of the ratio of 14C: 12C atoms rather than on counting the radioactivity of 14C. It is therefore possible to measure much lower levels of 14C in a sample much more rapidly than the conventional technique allows. Consequently, minimum sample size is reduced approximately 1000-fold and the datable time span of the method can, theoretically, be doubled. Greater selectivity, in the field and the laboratory, is the most important archaeological attribute of AMS 14C dating. It allows on-site chronological consistency to be tested by multiple sampling; archaeological materials to be dated that contain too little C, or are too rare or valuable, to be dated by the conventional method; and the validity of a date to be tested by isolating and independently dating particular fractions in chemically complex samples. In this paper, recent archaeological applications of the new technique are reviewed under these two headings: verification dating applied to the origin and spread of anatomically modern humans in Europe and the Americas, to putative evidence for early (pre-Neolithic) agriculture in Israel and Egypt, and to the dating of rare Palaeolithic and later artefacts; and the building of new and more-detailed chronologies illustrated by reference to Upper Palaeolithic sequences in Europe, Mesolithic-Neolithic sequences in Southwest Asia, and Neolithic-Bronze Age chronologies in Britain. (author)

  1. Radiocarbon analysis of the EPICA Dome C ice core: no in situ 14C from the firn observed

    International Nuclear Information System (INIS)

    CO2 and CO obtained by dry-extraction from ice samples of the EPICA Dome C core were 14C analysed by AMS. For some of the ice samples there is no evidence for in situ 14C, indicating the firn did not retain 14C. The 14C ages of these samples are too old in comparison with a calibrated ice-flow model, and the concentrations of 14CO are near zero. For other ice samples, however, in situ 14C is clearly present, and is likely from post-coring exposure at the Dome C surface. These samples show too young 14C ages, and distinct concentrations of 14CO. The accuracy of ages obtained from 14C analysis of ice samples is discussed

  2. Radioactive waste with 14C in Argentina

    International Nuclear Information System (INIS)

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

  3. Allocation and residence time of photosynthetic products in a boreal forest using a low-level 14C pulse-chase labeling technique

    OpenAIRE

    Carbone, MS; Czimczik, CI; McDuffee, KE; Trumbore, SE

    2007-01-01

    Much of our understanding about how carbon (C) is allocated in plants comes from radiocarbon (14C) pulse-chase labeling experiments. However, the large amounts of 14C required for decay-counting mean that these studies have been restricted for the most part to mesocosm or controlled laboratory experiments. Using the enhanced sensitivity for 14C detection available with accelerator mass spectrometry (AMS), we tested the utility of a low-level 14C pulse-chase labeling technique for quantifying ...

  4. 14C Behaviour in PWR coolant

    International Nuclear Information System (INIS)

    Although 14C is produced in relatively small amounts in PWR coolant, it is important to know its fate, for example whether it is released by gaseous discharge, removed by absorption on ion exchange (IX) resins or deposited on the fuel pin surfaces. 14C can exist in a range of possible chemical forms: inorganic carbon compounds (probably mainly CO2), elemental carbon, and organic compounds such as hydrocarbons. This paper presents results from a preliminary survey of the possible reactions of 14C in PWR coolant. The main conclusions of the study are: - A combination of thermal and radiolytic reactions controls the chemistry of 14C in reactor coolant. A simple chemical kinetic model predicts that CH3OH would be the initial product from radiolytic reactions of 14C following its formation from 17O. CH3OH is predicted to arise as a result of reactions of OH. with CH4 and CH3, and it persists because there is no known radiation chemical reduction mechanism. - Thermodynamic considerations show that CH3OH can be thermally reduced to CH4 in PWR conditions, although formation of CO2 from small organics is the most thermodynamically favourable outcome. Such reactions could be catalysed on active nickel surfaces in the primary circuit. - Limited plant data would suggest that CH4 is the dominant form in PWR and CO2 in BWR. This implies that radiation chemistry may be important in determining the speciation. - Addition of acetate does not affect the amount of 14C formed, but the addition of large amounts of stable carbon would lead to a large range of additional products, some of which would be expected to deposit on fuel pin surfaces as high molecular weight hydrocarbons. However, the subsequent thermal decomposition reactions of these products are not known. - Acetate addition may represent a small input of 12C compared with organic material released from CVCS resins, although the importance of this may depend on whether that is predominantly soluble material or suspended

  5. The contribution of AMS to geosciences

    International Nuclear Information System (INIS)

    Full text: This presentation outlines some of the advances in AMS methods with emphasis on Australian examples and measurements using the accelerators at ANSTO and the Australian National University. Perhaps the best known of these techniques is the application of AMS 14C dating which has the advantage of needing much smaller amounts of sample (typically 14C determinations by β counting. AMS 14C has been applied to dating an enormous array of materials including archaeological samples and sites, tree rings, ice cores, banding in coals and circulation and ventilation changes in the world's oceans. An exciting application of the measurement of the rare long-lived isotopes 10Be, 26Al and 36Cl is in the relatively new field of cosmogenic exposure dating. Accumulation of these cosmogenically produced nuclides formed in-situ in exposed rock surfaces is used to estimate both the time of exposure of the rock surface and mean erosion rates. A large variety of landscape-related processes have been successfully addressed including weathering and sediment-transport rates and the ages of glacial retreat, tectonic uplift and lava eruptions. In the field of hydrology, 36Cl studies of dissolved chloride have been used to successfully estimate the ages of ground waters and trace their origins. The tracing of atmospheric air masses that deliver rain and the origin of Australian salt lakes and continental salinisation using 36Cl lead to important conclusions on the origin and residence time of chloride in the Australian landscape. The ultimate origin of the bulk of the surficial chloride in Australia is shown to be meteoric, and for the western part of the continent, a mean residence time of about 0.75 Ma pertains. The realisation of the long-term and continuing delivery of salts to the landscape needs recognition in planning strategies to combat salinisations of agricultural areas

  6. A decade of AMS at University of Georgia

    Energy Technology Data Exchange (ETDEWEB)

    Culp, Randy, E-mail: rculp@uga.edu [Center for Applied Isotope Studies, University of Georgia, Athens, GA (United States); Noakes, John; Cherkinsky, Alex; Ravi Prasad, G.V.; Dvoracek, Doug [Center for Applied Isotope Studies, University of Georgia, Athens, GA (United States)

    2013-01-15

    In a span of 10 years, University of Georgia's Center for Applied Isotope Studies (CAIS) has transformed itself from principally a liquid scintillation counting (LSC) laboratory to one conducting thousands of accelerator mass spectrometry (AMS) and stable isotope ratio analysis (SIRA) annually. After receiving the first of the NEC compact AMS units in the United States, the CAIS began to meet the demand for {sup 14}C analysis outside the normal realm of most radiocarbon dating laboratories. With industry's support, isotope research continued on an already developing natural products program to authenticate materials origin and process of formation. The CAIS's AMS allowed for the detection of synthetic materials in milligram quantities rather than gram quantities required by LSC and allowed new compound specific SIRA techniques to be directed toward compound specific {sup 14}C measurement. By 2005 the CAIS was one of only a few laboratories accredited to determine bio-base content in industrial fuels and products by both AMS and LSC following ASTM D6866-10 [1]. Since 2001, when our first sample was analyzed by AMS method, both radiocarbon and natural products sample numbers have increased steadily. The advantages of AMS analysis in overall efficiency, cost savings, accuracy, and precision, are detailed here in a review of analytical precision for radiocarbon and natural products analyzed over 10 years of AMS operation. Comparisons are made between natural products and bio-based materials analyzed by both AMS and LSC. Although high precision is not required to authenticate natural products, for the purpose of product comparison with regard to degree of naturalness accurate and precise {sup 14}C measurement is shown to be achievable by both methods.

  7. Translocation of 14C-assimilates and 14C-herbicides in cow parsnip (Heracleum sphondylium)

    International Nuclear Information System (INIS)

    In cow parsnip translocation fo 14CO2, 14C-2,4-D and 14C-2,4,5-T was investigated during four growth phases. It was intended to find out the quantitative correlation between the translocation of phenoxy herbicides and assimilates. The gas exchange used for 14CO2 application is described. Before shoot extension, the root of the plants is the prefered target for assimilates and 2,4-D. Close quantitative correlation was found between the respective 14C activities as regards direction of translocation and radioactivity per dry weight. Similar results were found with 2,4,5-T. At flowering 14C activity moves clearly into the shoot and the inflorescence. At seed maturity, rhizomes and roots take in the 14C activity preferably. Consequently, two growing phases are recommended for optimal weed control by phenoxy compounds, especially 2,4-D: before shooting or after flowering, if sufficient assimilating leaves are left. (orig.)

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

    International Nuclear Information System (INIS)

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

  9. Characterization of recent Lake Tahoe fault activity: Combining Sub-Meter Resolution Seismic Imagery with AMS C-14 Dated Submerged Paleo-Surfaces.

    Science.gov (United States)

    Dingler, J. A.; Kent, G. M.; Babcock, J. A.; Driscoll, N. W.; Harding, A. J.; Gayes, P. T.; Karlin, B.; Morgan, C. W.; Heyvaert, A.; Richards, B. C.

    2002-12-01

    Deformational strain within the Lake Tahoe Basin was mapped during previous campaigns using a combination of high resolution seismic CHIRP, multi-beam swath bathymetry, and airborne laser altimetry. These previous campaigns identified submerged paleo-shorelines of Pleistocene to early Holocene age, which act as a tectonic strain marker due to fault related disruptions of this once flat surface, as well as significantly offset fault scarps. Building upon this previous work, specific sites were selected for additional investigation with seismic CHIRP and AMS C-14 dated vibra and piston cores. The combination of these three techniques is ideally suited for quantifying recent fault activity through the correlation of paleo-surfaces and accurate age determinations. Initial analysis of seismic CHIRP and piston coring conducted in Emerald Bay shows a complex normal fault system with a sedimentation rate much higher than other parts of the lake. Seismic CHIRP conducted near Zephyr Cove was able to image multiple paleo-shorelines. Vibra coring of these same surfaces recovered sands of the same consistency as beach sand. Additional piston cores were collected at various lake locations below 400 m depth, including two cores taken across the Stateline Fault. Core analysis and AMS C-14 dating combined with site-specific seismic CHIRP, and previous mapping, will improve chronological control on the fault activity within the Lake Tahoe Basin.

  10. Chemical characterization and AMS radiocarbon dating of the binder of a prehistoric rock pictograph at Tadrart Acacus, southern west Libya

    Czech Academy of Sciences Publication Activity Database

    Mori, F.; Ponti, R.; Messina, A.; Flieger, Miroslav; Havlíček, Vladimír; Sinibaldi, M.

    2006-01-01

    Roč. 7, - (2006), s. 344-349. ISSN 1296-2074 Institutional research plan: CEZ:AV0Z50200510 Keywords : rock pictograph * libya n sahara * radiocarbon dating Subject RIV: EE - Microbiology, Virology Impact factor: 0.738, year: 2006

  11. Carbon 14 dating method

    International Nuclear Information System (INIS)

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

  12. In situ determination of /sup 241/Am on Enewetak Atoll. Date of survey: July 1977-December 1979

    Energy Technology Data Exchange (ETDEWEB)

    Tipton, W.J.; Fritzsche, A.E.; Jaffe, R.J.; Villaire, A.E.

    1981-11-01

    An in situ gamma ray spectrometer system was operated at Enewetak Atoll from July 1977 to December 1979 in support of the Enewetak Cleanup Project. The system employed a high purity germanium planar detector suspended at a height of 7.4 m above ground. Conversion factors were established to relate measured photopeak count rate data to source concentration in the soil. Data obtained for /sup 241/Am, together with plutonium-to-americium ratios obtained from soil sample analyses, were used to establish area-averaged surface (0 to 3 cm) transuranic concentration values. In areas which exceeded cleanup criteria, measurements were made in an iterative fashion to guide soil removal until levels were reduced below the cleanup criteria. Final measurements made after soil removal had been completed were used to document remaining surface transuranic concentration values and to establish external exposure rate levels due to /sup 137/Cs and /sup 60/Co.

  13. AMS dating of a recently rediscovered juvenile human mandible from Solutré (Saône-et-Loire, France)

    OpenAIRE

    Pestle, William; Colvard, Michael; Pettitt, Paul

    2009-01-01

    Nearly 150 years of excavation at the Upper Paleolithic type-site of Solutré has yielded substantial evidence for Late Pleistocene human occupation, food procurement, and tool manufacture in the Mâconnais. To date, however, no human skeletal material from the Solutrean phase of this eponymous site has been discovered. Among the finds curated by the Field Museum of Natural History resulting from a relatively obscure and poorly documented excavation conducted at the heart of the site in 1896 is...

  14. Photoproton cross section for 14C

    International Nuclear Information System (INIS)

    Using bremsstrahlung, the 14C(γ,p) reaction cross section has been measured from threshold to 29 MeV. The integrated cross section up to 30 MeV is 18±3 MeV mb. Above 23.5 MeV, the reported cross section includes a contribution, estimated at 3.5 MeV mb, due to the 14C(γ,d) and 14Cγ,pn) reactions. Essentially the entire 14C(γ,p) cross section results from decay of T> dipole states. From knowledge of other decay channels estimates of the cross section, integrated to 30 MeV for the T and T> components of the giant resonance (GDR) of 81 MeV mb and 43 MeV mb are obtained. The splitting of the mean energies of the GDR isospin components is 8.5 MeV. Comparisons with several shell-model calculations are made with the data, and general agreement is found. A comparison of photonuclear absorption cross sections for 12,1314C and 16,17,18 O shows dramatic redistribution of dipole strength as neutrons are added to the core nuclei. 41 refs., 1 tab., 7 figs

  15. 14C measurements in aquifers with methane

    International Nuclear Information System (INIS)

    A survey of various groundwater systems indicates that methane is a common trace constituent and occasionally a major carbon species in groundwaters. Thermocatalytic methane had delta13CCH4 > -45%0 and microbially-produced or biogenic methane had delta13CCH4 0. Groundwaters containing significant biogenic methane had abnormally heavy delta13C values for the inorganic carbon. Thermocatalytic methane had no apparent effect on the inorganic carbon. Because methanogenesis seriously affects the carbon isotope geochemistry of groundwaters, the correction of raw 14C ages of affected groundwaters must consider these effects. Conceptual models are developed which adjust the 14C activity of the groundwater for the effects of methanogenesis and for the dilution of carbon present during infiltration by simple dissolution of rock carbonate. These preliminary models are applied to groundwaters from the Alliston sand aquifer where methanogenesis has affected most samples. In this system, methanogenic bacteria using organic matter present in the aquifer matrix as substrate, have added inorganic carbon to the groundwater which has initiated further carbonate rock dissolution. These processes have diluted the inorganic carbon 14C activity. (orig.)

  16. Methodological study on exposure date of Tiankeng by AMS measurement of in situ produced cosmogenic {sup 36}Cl

    Energy Technology Data Exchange (ETDEWEB)

    Dong Kejun [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); Li Shizhuo [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); CNNC China North Nuclear Fuel Company Ltd., Baotou 014035 (China); He Ming [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); Sasa, Kimikazu [Tandem Accelerator Complex, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Matsushi, Yuki [Disaster Prevention Research Institute, Kyoto University (Japan); Huang Baojian [Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004 (China); Ruan Xiangdong; Guan Yongjing [College of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Takahashi, Tsutomu [Tandem Accelerator Complex, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Sueki, Keisuke [Graduate School of Pure and Applied Sciences, University of Tsukuba (Japan); Li Chaoli; Wu Shaoyong [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); Wang Xianggao [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004 (China); Shen Hongtao [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); College of Physics and Technology, Guangxi Normal University, Guilin 541004 (China); Nagashima, Yasuo [Tandem Accelerator Complex, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Jiang Shan, E-mail: jiangs@ciae.ac.cn [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China)

    2013-01-15

    Tiankeng is a typical Karst relief of the late Quaternary Period. Studies on the exposure ages of Tiankeng are very important in geographical research to elucidate the formation condition, the developing process, and the features of biological species. {sup 36}Cl on the surface layer of the rupture cross-section of Tiankeng is largely produced by cosmogenic high-energy neutron induced reactions {sup 40}Ca(n, {alpha}p) and {sup 39}K(n, {alpha}), and has accumulated since the formation of the Tiankeng. Low-energy neutron reaction {sup 35}Cl(n, {gamma}) contributes a small portion of {sup 36}Cl. In this work, the concentration of the cosmogenic {sup 36}Cl in rock samples taken from Dashiwei Tiankeng, Leye County, Guangxi Zhuang Autonomous Region, China, was measured jointly by Accelerator Mass Spectrometry (AMS) laboratories of CIAE and University of Tsukuba in an effort to estimate the formation time (or exposure age) of the Tiankeng. The results show that the exposure time of Da Shiwei Tiankeng is about 26 {+-} 9.6 ka (without erosion correction). The sampling strategy and procedures, experimental set-up, and preliminary results will be presented in detail.

  17. Elements in biological AMS

    International Nuclear Information System (INIS)

    AMS (Accelerator Mass Spectrometry) provides high detection sensitivity for isotopes whose half-lives are between 10 years and 100 million years. 14C is the most developed of such isotopes and is used in tracing natural and anthropogenic organic compounds in the Earth's biosphere. Thirty-three elements in the main periodic table and 17 lanthanides or actinides have long lived isotopes, providing potential tracers for research in elemental biochemistry. Overlap of biologically interesting heavy elements and possible AMS tracers is discussed

  18. New AMS system at the JAERI-Mutsu

    Energy Technology Data Exchange (ETDEWEB)

    Aramaki, Takafumi; Togawa, Orihiko; Kitamura, Toshikatsu [Marine Research Laboratory, Japan Atomic Energy Research Institute, Mutsu, Aomori (Japan)

    2000-07-01

    A new AMS facility has been set up at the Japan Atomic Energy Research Institute (JAERI) in 1997 and {sup 14}C as well as {sup 129}I will be used for marine environmental studies. The 3 MV AMS system is capable to perform high precision {sup 14}C as well as heavy element AMS. The {sup 14}C-AMS section of the system has been accepted and its precision is comparable to other high precision {sup 14}C-AMS systems. A sample preparation system for the extraction of dissolved inorganic carbon from seawater has been built up. Accuracy checks of the sample preparation system and the {sup 14}C-AMS system have been carried out with international accepted {sup 14}C standard material. The heavy element section for {sup 129}I measurement has been accepted and its precision was verified by using international standard. (author)

  19. Future directions of the AMS program at Lucas Heights

    Energy Technology Data Exchange (ETDEWEB)

    Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1998-12-31

    The research program based on the ANTARES AMS spectrometer involves applications of the long-lived radionuclides {sup 14}C, {sup 10}Be, {sup 26}Al, {sup 36}Cl and {sup 129}I in earth sciences and archaeology. Examples of environmental applications of AMS at Lucas Heights include: use of the {sup 14}C bomb pulse to determine the age and age-spread of air trapped in Antarctic ice bubbles, key parameters to study the variability of CO{sub 2} and other greenhouse gases in the past; analyses of {sup 14}C bomb-pulse curves in tree rings from tropical regions and the southern hemisphere to improve our understanding of the carbon cycle and air-sea interactions, important processes for the global climate; analyses of {sup 10}Be and {sup 36}Cl produced in-situ in polished glacial bedrock and moraine boulders from Tasmania, New Zealand and Antarctica, as part of a major national project to unravel the timing of glacial cycles in the southern hemisphere. A recent archaeological application has been the radiocarbon dating of charcoal fragments from the rock shelter at Jinmium in the Northern Territory demonstrating that this site was occupied by Aboriginal people only during the late Holocene. In environmental monitoring, the analysis of {sup 129}I, {sup 14}C and {sup 36}Cl in water specimens from Mururoa and Fangatauga contributed to an IAEA study regarding residual radioactivity in the Pacific after the French nuclear program Extended abstract. 5 refs.

  20. Future directions of the AMS program at Lucas Heights

    International Nuclear Information System (INIS)

    The research program based on the ANTARES AMS spectrometer involves applications of the long-lived radionuclides 14C, 10Be, 26Al, 36Cl and 129I in earth sciences and archaeology. Examples of environmental applications of AMS at Lucas Heights include: use of the 14C bomb pulse to determine the age and age-spread of air trapped in Antarctic ice bubbles, key parameters to study the variability of CO2 and other greenhouse gases in the past; analyses of 14C bomb-pulse curves in tree rings from tropical regions and the southern hemisphere to improve our understanding of the carbon cycle and air-sea interactions, important processes for the global climate; analyses of 10Be and 36Cl produced in-situ in polished glacial bedrock and moraine boulders from Tasmania, New Zealand and Antarctica, as part of a major national project to unravel the timing of glacial cycles in the southern hemisphere. A recent archaeological application has been the radiocarbon dating of charcoal fragments from the rock shelter at Jinmium in the Northern Territory demonstrating that this site was occupied by Aboriginal people only during the late Holocene. In environmental monitoring, the analysis of 129I, 14C and 36Cl in water specimens from Mururoa and Fangatauga contributed to an IAEA study regarding residual radioactivity in the Pacific after the French nuclear program

  1. Assessing open-system behavior of 14C in terrestrial gastropod shells

    Science.gov (United States)

    Rech, J.A.; Pigati, J.S.; Lehmann, S.B.; McGimpsey, C.N.; Grimley, D.A.; Nekola, J.C.

    2011-01-01

    In order to assess open-system behavior of radiocarbon in fossil gastropod shells, we measured the 14C activity on 10 aliquots of shell material recovered from Illinoian (~190-130 ka) and pre-Illinoian (~800 ka) loess and lacustrine deposits in the Midwestern USA. Eight of the 10 aliquots yielded measurable 14C activities that ranged from 0.25 to 0.53 percent modern carbon (pMC), corresponding to apparent 14C ages between 48.2 and 42.1 ka. This small level of open-system behavior is common in many materials that are used for 14C dating (e.g. charcoal), and typically sets the upper practical limit of the technique. Two aliquots of gastropod shells from the Illinoian-aged Petersburg Silt (Petersburg Section) in central Illinois, USA, however, yielded elevated 14C activities of 1.26 and 1.71 pMC, which correspond to apparent 14C ages of 35.1 and 32.7 ka. Together, these results suggest that while many fossil gastropods shells may not suffer from major (>1%) open-system problems, this is not always the case. We then examined the mineralogy, trace element chemistry, and physical characteristics of a suite of fossil and modern gastropod shells to identify the source of contamination in the Petersburg shells and assess the effectiveness of these screening techniques at identifying samples suitable for 14C dating. Mineralogical (XRD) and trace element analyses were inconclusive, which suggests that these techniques are not suitable for assessing open-system behavior in terrestrial gastropod shells. Analysis with scanning electron microscopy (SEM), however, identified secondary mineralization (calcium carbonate) primarily within the inner whorls of the Petersburg shells. This indicates that SEM examination, or possibly standard microscope examination, of the interior of gastropod shells should be used when selecting fossil gastropod shells for 14C dating. ?? 2011 by the Arizona Board of Regents on behalf of the University of Arizona.

  2. Radiometric dating

    International Nuclear Information System (INIS)

    The paper on radiometric dating is a chapter in a handbook of Holocene Palaeoecology and Palaeohydrology. This chapter is part of a section on dating methods. Radiocarbon dating is discussed with respect to the apparent ages of lake sediments, seawater, sea creatures and plants. Isotope dating methods for the late Holocene deposits involving 210Pb, 137Cs, sup(239, 240)Pu, 241Am, 32Si and 39Ar are also described. (U.K.)

  3. Synthesis of dexamethasone-4-14C

    International Nuclear Information System (INIS)

    The bismethylenedioxy (BMD) derivative of dexamethasone 2 was silylated with trimethylchlorosilane and imidazole in dimethylformamide to give the 11β-trimethylsilyloxy BMD derivative 3. The Δ1-double bond in 3 was hydrogenated over 5% palladium on carbon to give the Δ4-3-oxo steroid 4. Oxidation of 4 with potassium permanganate-sodium metaperiodate gave the seco-acid 5 which on subsequent treatment with acetic anhydride; sodium acetate and triethylamine gave the enol-lactone 6. The enol-lactone 6 was reacted with 14C-methylmagnesium iodide to give an adduct 7a which on heating at reflux with lithium 2,6-di-t-butylphenoxide in dioxane gave the Δ4-3-oxo derivative 8. Compound 8 was heated at reflux with m-iodylbenzoic acid and diphenyl diselenide in toluene to give the Δsup(1,4)-3-oxo steroid 9. The protecting BMD and silyl groups were removed in a single step by reaction with aqueous trifluoroacetic acid containing 2N hydrochloric acid at room temperature to give dexamethasone-4-14C 10. (author)

  4. C-14 bomb peak dating of human DNA samples at the microgram level

    International Nuclear Information System (INIS)

    The preparation of carbon samples below 10 μg for 14C AMS measurements is still a challenging task. In a collaboration between the Karolinska Institute in Stockholm and the VERA Laboratory in Vienna, we developed graphite sample preparation methods in the μg range for measuring 14C in genomic DNA extracted from neuronal cells of the human brain. Emphasis was put on the reduction of carbon background throughout the whole sample preparation process. 14C measurements of μg-size DNA samples allows one to perform retrospective 14C bomb peak dating of neurons from the human olfactory bulb, thereby studying possible neurogenesis in this small region of the human brain. First 14C AMS measurements from this material were performed with graphitized samples between 2.3 and 3.7 μg C. A precision of 1.8 to 3.5 % for 14C/12C ratio measurements could be achieved. Sample preparation and carbon background investigations currently applied at VERA for μg-size carbon samples will be presented. Furthermore, the potential of applying the method to study the human olfactory bulb will be discussed. (author)

  5. Pharmacokinetics and tissue distribution of 14C-5-aminosalicylic acid (14C-5-ASA) in rats

    International Nuclear Information System (INIS)

    5-Aminosalicylic acid (5-ASA) is effective in the treatment of ulcerative colitis and Crohn's disease. As part of a preclinical metabolism profile with 5-ASA, we evaluated the tissue level and distribution of 14C-5-ASA in rats. Biodistribution of 14C-radioactivity was determined in the major organs of rats after a single oral dose (34 mg/kg; 15 uci/rat). Data from tissue area under the curve (AUC 0-72) indicated that the highest amounts of radioactivity were retained in cecum (481.1 hr.ug.equ/gm), colon-rectum (178.5 hr.ug.equ/gm), ileum (166.7 hr.ug.equ/gm), jejunum (65.5 hr.ug.equ/gm), followed by kidneys (58.0 hr.ug.equ/gm) and liver (14.8 hr.ug.equ/gm). The radioactivity retained in tissues at 72 hours postdose was wither nondetectable or less than 0.1 ppm. The radioactivity concentration in blood was highest at 0.5 hr (tmax) postdose and the terminal half-life (t1/2) of 14C-radioactivity (5-ASA + metabolite) was 2.7 hours. 14C-5-ASA is absorbed and distributed in the body. The greatest amount of 14C-radioactivity was found in the stomach and GI tract. 14C-5-ASA was eliminated completely (44.9% in the urine, 51.7% in the feces) 72 hours after administration without significant tissue retention

  6. Cazadores recolectores del Holoceno Medio y Superior de la cueva Haichol, región cordillerana central del Neuquén, República Argentina : Cronología 14C-AMS sobre colágeno óseo y su conversión a tiempo calendario. Signaturas isotópicas del carbono y del nitrógeno en el colágeno óseo, en función de trazadores paleodietéticos

    OpenAIRE

    Fernández C., Jorge; Panarello, Héctor

    2001-01-01

    Se presentan ocho fechados 14C-AMS sobre colágeno de huesos craneanos sin alteración diagenética, provenientes de la cueva de Haichol, Neuquén, que serán discutidos con el propósito de adquirir conocimientos más precisos relativos a cronología, paleodieta, entorno paleoambiental del sitio y de sus ocupantes prehistóricos. Un primer grupo de fechados remonta al temprano Holoceno m.edio, abarca el rango de edades 6570 - 5850 años cal. AP (2 s) e incluye morfotipos humanos de notable interés pal...

  7. Comparison of different soil organic matter fractionation methodologies: Evidences from ultrasensitive 14C measurements

    International Nuclear Information System (INIS)

    Soils are studied with the aim to predict future climatic scenarios and find the best guidelines to manage terrestrial ecosystems for the mitigation of the atmospheric CO2 rising. Carbon constituting soil organic matter (SOM) behaves as a cohort of different pools, characterized by a specific C turnover time. Both natural and anthropogenic occurring 14C reach the soil through plant littering, becoming a valid tool to trace SOM dynamics. In this study we present a series of Accelerator Mass Spectrometry (AMS) 14C measurements on SOM samples obtained by means of different laboratory protocols used for the isolation of soil pools from bulk soil (fractionation protocols). Radiocarbon signature of SOM fractions is used as a keyhole to look at the more effective fractionation procedure and comparison among measured 14C on SOM fractions revealed important indications for the proposal of a novel fractionation protocol. Our data put in evidence how particle size controls the recalcitrance of ancient SOM carbon pools.

  8. Mass accumulation rates and fallout radionuclides 210Pb, 137Cs and 241Am inventories determined in radiometrically dated abyssal sediments of the Black Sea

    International Nuclear Information System (INIS)

    Five abyssal (deep-sea) sediment cores collected during the two international cruises on R/V 'Professor Vodyanitskiy' (RADEUX-1998 and RADEUX-2000) in the framework of the Regional Technical Co-operation Project RER/2/003 'Marine Environmental Assessment in the Black Sea Region' were subjected to detailed radiometric analysis. The sediments were dated using the radionuclides 210Pb, 137Cs and 241Am and the results used to calculate a number of key parameters, e.g. radionuclide inventories, fluxes and sediment accumulation rates. The sediment cores were collected using a MARK II-400 multi-corer (Bowers and Connelly) in both Western and Eastern sub-basins of the Black Sea. The cores were sliced on board with a resolution of 0.2-0.4 cm for the top 5 cm and 1-5 cm downward using an extruder that was specially designed to prevent loss of the uppermost fluff-layer, possible down-smearing and interlayer cross-contamination of the sediment. Dry bulk density (DBD) and cumulative dry mass (CDM) were calculated on a salt-free basis using direct determination of the salt contribution to the dry mass of the sediment. Calculations showed that in the near surface sediments, and particularly in the top fluff-layer, the salt dissolved in pore-water contributed up to 30-60% of the mass of dried sediments. Neglecting this correction could cause an erroneous interpretation of the 210Pb activity profile, resulting in overestimation of both the average sedimentation rate and its recent temporal changes. Sediment samples were analysed for 210Pb, 226Ra, 137Cs and 241Am by direct gamma assay in UHMI after 3 weeks equilibration in hermetically sealed plastic holders, using an EG and G Ortec (Ametek) HPGe GWL series well-type coaxial low background intrinsic germanium detector. Correction was made for the effect of self-absorption of low energy γ-rays within the sample using attenuation parameters determined in. Chronostratigraphical analysis of the data and sediment age calculation have

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

    International Nuclear Information System (INIS)

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

  10. A novel synthesis of ethanolamine-2-14C

    International Nuclear Information System (INIS)

    Ethanolamine-2-14C was prepared by the reduction of benzyloxycarbonyl-glycine-1-14C methyl ester. The reduction was carried out with calcium borohydride and the protecting group was removed by hydrogenolysis. (author)

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

    Data.gov (United States)

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

  12. Dating megafaunal extinction on the Pleistocene Darling Downs, eastern Australia: the promise and pitfalls of dating as a test of extinction hypotheses

    Science.gov (United States)

    Price, Gilbert J.; Webb, Gregory E.; Zhao, Jian-xin; Feng, Yue-xing; Murray, Andrew S.; Cooke, Bernard N.; Hocknull, Scott A.; Sobbe, Ian H.

    2011-04-01

    A key to understanding Late Pleistocene megafaunal extinction dynamics is knowledge of megafaunal ecological response(s) to long-term environmental perturbations. Strategically, that requires targeting fossil deposits that accumulated during glacial and interglacial intervals both before and after human arrival, with subsequent palaeoecological models underpinned by robust and reliable chronologies. Late Pleistocene vertebrate fossil localities from the Darling Downs, eastern Australia, provide stratigraphically-intact, abundant megafaunal sequences, which allows for testing of anthropogenic versus climate change megafauna extinction hypotheses. Each stratigraphic unit at site QML796, Kings Creek Catchment, was previously shown to have had similar sampling potential, and the basal units contain both small-sized taxa (e.g., land snails, frogs, bandicoots, rodents) and megafauna. Importantly, sequential faunal horizons show stepwise decrease in taxonomic diversity with the loss of some, but not all, megafauna in the geographically-small palaeocatchment. The purpose of this paper is to present the results of our intensive, multidisciplinary dating study of the deposits (>40 dates). Dating by means of accelerator mass spectrometry (AMS) 14C (targeting bone, freshwater molluscs, and charcoal) and thermal ionisation mass spectrometry U/Th (targeting teeth and freshwater molluscs) do not agree with each other and, in the case of AMS 14C dating, lack internal consistency. Scanning electron microscopy and rare earth element analyses demonstrate that the dated molluscs are diagenetically altered and contain aragonite cements that incorporated secondary young C, suggesting that such dates should be regarded as minimum ages. AMS 14C dated charcoals provide ages that occur out of stratigraphic order, and cluster in the upper chronological limits of the technique (˜40-48 ka). Again, we suggest that such results should be regarded as suspicious and only minimum ages. Subsequent

  13. Accelerator mass spectrometry measurements of the 13C (n ,γ )14C and 14N(n ,p )14C cross sections

    Science.gov (United States)

    Wallner, A.; Bichler, M.; Buczak, K.; Dillmann, I.; Käppeler, F.; Karakas, A.; Lederer, C.; Lugaro, M.; Mair, K.; Mengoni, A.; Schätzel, G.; Steier, P.; Trautvetter, H. P.

    2016-04-01

    The technique of accelerator mass spectrometry (AMS), offering a complementary tool for sensitive studies of key reactions in nuclear astrophysics, was applied for measurements of the 13C (n ,γ )14C and the 14N(n ,p )14C cross sections, which act as a neutron poison in s -process nucleosynthesis. Solid samples were irradiated at Karlsruhe Institute of Technology with neutrons closely resembling a Maxwell-Boltzmann distribution for k T =25 keV, and also at higher energies between En=123 and 182 keV. After neutron irradiation the produced amount of 14C in the samples was measured by AMS at the Vienna Environmental Research Accelerator (VERA) facility. For both reactions the present results provide important improvements compared to previous experimental data, which were strongly discordant in the astrophysically relevant energy range and missing for the comparably strong resonances above 100 keV. For 13C (n ,γ ) we find a four times smaller cross section around k T =25 keV than a previous measurement. For 14N(n ,p ), the present data suggest two times lower cross sections between 100 and 200 keV than had been obtained in previous experiments and data evaluations. The effect of the new stellar cross sections on the s process in low-mass asymptotic giant branch stars was studied for stellar models of 2 M⊙ initial mass, and solar and 1 /10th solar metallicity.

  14. Measurement and evaluation of the 14C concentration in the collagen of the teeth among the Chinese

    International Nuclear Information System (INIS)

    Objective: The concentration of 14C in the collagen of the teeth among people with different ages was measured to understand concentration of 14C in the environment and human body of China influenced by 14C produced by nuclear weapon tests in the world in the past decades. Methods: Forth-eight eighth permanent teeth of some Shanghai residents born from 1920 to 1977 were collected. The teeth were cleaned and decalcified for the extraction of collagen and then were oxidized by high temperature and reduced into carbide graphite. The 14C was measured using an accelerator mass spectrometer (AMS), and the concentration of 14C was obtained by correction of 13C. Results: The concentration of 14C in the collagen of the teeth showed apparent variation in people born in different years: those born before 1940 around the level of background and those born from 1941 gradually increase, those born 1951 reached the peak value-58%, those born after 1951 presented a tendency of decrease. Conclusion: The results of this study indicated there is the same tendency of change in concentration of 14C in teeth and previously reported human tissue and plant. Also there is same variation in concentration of 14C in both Chinese and Japanese teeth; it also correlates with the numbers of atmospheric testing of nuclear weapons in the world

  15. Progress report on a novel in situ14C extraction scheme at the University of Cologne

    Science.gov (United States)

    Fülöp, R.-H.; Wacker, L.; Dunai, T. J.

    2015-10-01

    We present initial results of in situ14C system blank and calibration sample measurements obtained using the in situ14C extraction scheme developed at the University of Cologne. The 14C extraction scheme specifically exploits the phase transformation of quartz to cristobalite in order to quantitatively extract the carbon as CO2 and follows a scheme that is different to that of existing extraction systems. Features are offline furnace extraction, single pass catalytic oxidation using mixed copper (I,II) oxide as catalyst, the use of UHV-compatible components and of vacuum annealed copper tubing. The design allows a relatively rapid sample throughput - two samples per day as opposed to the current 2 days per sample that can be done on other lines - and can accommodate samples ranging between 0.5 and 4 g of clean quartz. Following extraction and cleaning, the CO2 gas is measured using the gas ion source of the MICADAS AMS facility at ETH Zurich. The extraction system yields low systems blanks (10 +16/-10 × 103 atoms 14C, ±1 σ) and the initial results indicate that further improvements are achievable. Measurements of the CRONUS-A standard sample show a good reproducibility and results are consistent with published values. We also present the first in situ14C results for the CRONUS-R standard material.

  16. Radiocarbon dating of artworks

    OpenAIRE

    Krajcar Bronić, Ines; Horvatinčić, Nada; Barešić, Jadranka; Sironić, Andreja

    2015-01-01

    Absolute dating of artworks and cultural heritage objects is one of the most important issues in art history studies and essential for evaluating original art objects, differentiating between originals and later imitations and/or frauds and recognizing subsequent repairs and restauration works. The radiocarbon dating (14C dating) method is one of the most well-known radiometric methods of absolute dating, which can be applied for dating materials of biogenic origin, such as wood, charcoal, bo...

  17. Endosulfan - 14C: degradation in soil

    International Nuclear Information System (INIS)

    The degradation of (14C) endosulfan was studied after incubation in sterilized and non-sterilized samples of three oxisols, most frequently cultivated with cotton, in Brazil. In sterilized soils the extracted residues were about 80% the bound residues varied from 6 to 14% and the total residues, from 90 to 102%, presenting small variation during a period of 160 days of incubation. The non-sterilized soils, after 160 days of incubation, showed 38, 45 and 43% of extracted residue; 34, 23 and 30% of bound residue; and 72, 68 and 73% of total residue. The evolution of CO2 was very low in the three soil types, being 0.3% and 0.4% in sterilized and non-sterilized soils, respectively, during a period of 48 days of incubation. These low values showed that no great mineralization of endosulfan occurred in this period. TLC analyses of extracted residue showed differences for sterilized and non-sterilized soils. In sterilized soil appeared alpha endosulfan, beta endosulfan, endosulfan sulfate, while in non-sterilized soils appeared alpha and beta endosulfan, endosulfan sulfate and endosulfan diol. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  19. Using 3H and 14C to constrain the degree of closed-system dissolution of calcite in groundwater

    International Nuclear Information System (INIS)

    Highlights: ► δ13C and 87Sr/86Sr in Ovens groundwater imply substantial carbonate dissolution. ► 3H vs. 14C imply negligible closed-system calcite dissolution. ► Calcite dissolution largely open-system process. ► Recognising open-system calcite dissolution important for dating deeper groundwater. - Abstract: This study uses 3H concentrations, 14C activities (a14C), 87Sr/86Sr ratios, and δ13C values to constrain calcite dissolution in groundwater from the Ovens catchment SE Australia. Taken in isolation, the δ13C values of dissolved organic C (DIC) and 87Sr/86Sr ratios in the Ovens groundwater imply that there has been significant calcite dissolution. However, the covariance of 3H and 14C and the calculated initial 14C activities (a014C) imply that most groundwater cannot have dissolved more than 20% of 14C-free calcite under closed-system conditions. Rather, calcite dissolution must have been partially an open-system process allowing 13C and 14C to re-equilibrate with CO2 in the unsaturated zone. Recognising that open-system calcite dissolution has occurred is important for dating deeper groundwater that is removed from its recharge area in this and other basins. The study is one of the first to use 14C and 3H to constrain the degree of calcite dissolution and illustrates that it is a valuable tool for assessing geochemical processes in recharge areas

  20. Synthesis of 1-[14C]methyl-1H-tetrazole-5-thiol([14C]NMTT) and [NMTT-[14C

    International Nuclear Information System (INIS)

    The title compounds were prepared for metabolic studies, with the 14C labelling being made at methyl of the 1-methyl-1H-tetrazol-5-ylthio (NMTT) group in overall radiochemical yields of 26% and 22% based on barium [14C]carbonate, respectively. (author)

  1. 14C determination in different bio-based products

    Science.gov (United States)

    Santos Arévalo, Francisco-Javier; Gómez Martínez, Isabel; Agulló García, Lidia; Reina Maldonado, María-Teresa; García León, Manuel

    2015-10-01

    Radiocarbon determination can be used as a tool to investigate the presence of biological elements in different bio-based products, such as biodiesel blends. These products may also be produced from fossil materials obtaining the same final molecules, so that composition is chemically indistinguishable. The amount of radiocarbon in these products can reveal how much of these biological elements have been used, usually mixed with petrol derived components, free of 14C. Some of these products are liquid and thus the handling at the laboratory is not as straightforward as with solid samples. At Centro Nacional de Aceleradores (CNA) we have tested the viability of these samples using a graphitization system coupled to an elemental analyzer used for combustion of the samples, thus avoiding any vacuum process. Samples do not follow any chemical pre-treatment procedure and are directly graphitized. Specific equipment for liquid samples related to the elemental analyzer was tested. Measurement of samples was performed by low-energy AMS at the 1 MV HVEE facility at CNA, paying special attention to background limits and reproducibility during sample preparation.

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

    International Nuclear Information System (INIS)

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

  3. Seasonal variations of 14C and δ13C for cave drip waters in Ryugashi Cave, Shizuoka Prefecture, central Japan

    Science.gov (United States)

    Minami, Masayo; Kato, Tomomi; Horikawa, Keiji; Nakamura, Toshio

    2015-11-01

    Speleothem 14C has recently emerged as a potentially powerful proxy for hydrology changes in comparison with atmospheric 14C calibration curve, rather than as a direct dating tool, apart from a time marker using bomb peak of 14C. Some possible causes for the relationship between speleothem 14C content (or dead carbon fraction: DCF) and karst hydrology have been proposed, such as changes in temperature, precipitation, drip water flow dynamics, cave air ventilation, soil air pCO2. In this study, we investigated seasonal variation in 14C and δ13C of drip water in Ryugashi Cave, Shizuoka Prefecture, central Japan, to examine the causes of the 14C and δ13C variations in a speleothem. The results show that different 14C concentrations and δ13C values of drip water from the Ryugashi Cave, were exhibited at different sites of the Caves No. 1, No. 3, and No. 4, which have different temperature, air pCO2, and flow paths. Further, the 14C and δ13C of drip waters showed seasonal variations at all sites, which were lower in fall and winter, and higher in spring and summer, though the extent of the variations was different among the sites. The 14C in drip waters tended to be correlated with the drip rates: 14C tended to be higher in drip waters with higher drip rates, and also correlated with rainfall amount around the Ryugashi Cave, especially for the drip waters in Cave No. 3, which are considered to have simpler flow paths. The increase in rainfall amount could bring the increase in drip rate of drip water, and then the decrease in interaction between solution and karst, resulting in 14C increase (DCF decrease) in drip water. Accordingly, the reconstruction of precipitation could be performed using 14C variation in a speleothem formed by drip water with simple flow dynamics.

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

    International Nuclear Information System (INIS)

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

  5. Method of preparing orotic acid labelled with radioisotope 14C

    International Nuclear Information System (INIS)

    The method is presented of universally labelled (U-14C)-orotic acid of a mole activity higher than 250 mCi/mMole. The Claisen condensation with (1,2-14C)-oxalic acid ethylester and (1,2-14C)-acetic acid ethylester having mole activities higher than 50 mCi/milliatom 14C results in the sodium salt of (U-14C)-oxalacetic acid ethylester. When reacted with S-methyl-(14C)-isothiouronium iodide (having an activity higher than 50 mCi/mMole), the substance yields S-methyl-(U-14C)-2-thioorotic acid ethylester whose hydrolysis in an acid medium results in (U-14C)-orotic acid. The (U-14C)-orotic acid can easily be separated from the reaction mixture in the form of precipitate which chemically and radiochemically is almost pure. When an inactive oxalic acid ethylester is used for synthesis, (2,4,5-14C)-orotic acid of a mole activity higher than 150 mCi/mMole can be prepared using the procedure described. (B.S.)

  6. L’apport des analyses 14C à l’étude de la nécropole de l’âge du Bronze de“ La Croix de la Mission ” à Marolles-sur-Seine The contribution of radiocarbon dating in the study of the Bronze Age cemetery of Marolles-sur-Seine “ La Croix de la Mission ”

    Directory of Open Access Journals (Sweden)

    Rebecca Peake

    2006-12-01

    Full Text Available Quatorze des 41 sépultures de la nécropole de “ la Croix de la Mission ” à Marolles-sur-Seine ont récemment fait l’objet d’une datation par le radiocarbone aux laboratoires de Groningen (Pays-Bas et de Lyon (France. Les résultats obtenus mettent en évidence l'utilisation en continu de la nécropole pendant plus d’un millénaire entre 2000 et 800 av. n. è. La corrélation entre ces nouvelles dates et les données archéologiques permet de cerner, avec plus de précision, l’éventail des différentes étapes chrono-culturelles représentées à travers les sépultures de la nécropole. [Les analyses 14C ont été effectuées par les laboratoires de Groningen (Centrum voor Isotopen Onderzoek Rijksuniversiteit Groningen Nijenborgh 4 NL-9747 AG Groningen et Lyon (Centre de Datation par le Radiocarbone Université Claude Bernard Lyon 1, 43, bd du 11 Novembre 1918 F-69622 Villeurbanne Cedex.]Fourteen of the 41 burials of the “ la Croix de la Mission ” Bronze Age cemetery at Marolles-sur-Seine have recently been carbon dated by the Lyon (France and Groningen (Netherlands laboratories. These new dates confirm the site’s occupation for more than 1000 years from 2000 BC to 800 BC and determine more precisely the different cultural and chronological phases of the cemetery illustrated by the great range of its burials.

  7. 14C Carbofuran residue in rice-fish ecosystem model

    International Nuclear Information System (INIS)

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

  8. 14C Activity and Global Carbon Cycle Changes over the Past 50,000 Years

    Science.gov (United States)

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

    2004-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  11. Stability of 125I and 14C labelled boom clay organic matter

    International Nuclear Information System (INIS)

    The candidate host formation for the disposal of radioactive waste in Belgium is boom clay which may contain up to 4% organic matter (OM). A limited fraction (less than 0.05%) of this OM is mobile. OM can complex radionuclides and so influence their migration. The migration behaviour of the OM itself has been extensively studied but to date such studies have used absorbancy measurements to quantify the OM. Unfortunately various problems accompany the use of absorbancy measurements. The particular problems may be overcome by using radiolabelled OM. Accordingly as a precursor to planned in situ migration experiments in boom clay (BC) using radiolabelled OM, stability studies on 125I and 14C labelled materials have been conducted. The 125I containing solutions were analysed using gel permeation chromatography (GPC) and the 14C solutions using high performance size exclusion chromatography (HPSEC). Dissappointingly at the relevant pH of 8.5, even in the absence of the clay, the 125I label was found to be unstable. However the 14C labelled OM (14C-BC-OM) was stable under the mild conditions employed in the test, so its stability was investigated in the presence of boom clay. The results were compared with that of 14C labelled humic acids (14C-HA), treated similarly. Unexpectedly the 14C labelled material was found to be partially unstable in the presence of boom clay. However the instability has not hampered the laboratory column experiments and should not hamper the proposed in situ experiments with this material. (orig.)

  12. Incorporation of 14C in chemical constituents of algal cells

    International Nuclear Information System (INIS)

    Two marine algal species Dunaliella premodecta, Chlamydemonas sp. and one fresh water species Scenedesmus obliquus were studied for 14C incorporation under laboratory conditions. The uptake of 14C in dry marine algal species was found to be more compared to that in fresh water species for the same initial concentration in the respective media. A sequential extraction technique was employed to study the distribution of 14C in different organic constituents. 14C fixation was found to be more in fatty acid fractions followed by protein and nucleoprotein fraction. (author). 13 refs., 2 tabs

  13. Synthesis of psilocin labelled with 14C and 3H

    International Nuclear Information System (INIS)

    14C- and 3H-labelled psilocin (4-hydroxy-N,N-dimethyl-tryptamine), the principal, active agent of hallucinogenic mushrooms, was synthesized from 2-methyl-3-nitrophenol via 4-benzyloxyindole. 14C-Labelled potassium cyanide was reacted with 4-benzyloxygramine (obtained from 4-benzyloxyindole) to give 14C-4-benzyloxy-3-indole acetic acid, an intermediate for 14C-psilocin synthesis. 3H-Labelled lithium aluminium hydride was used to react with 4-benzyloxy-3-indole-N,N-dimethyl-glyoxylamide (obtained from 4-benzyloxyindole) to give 3H-4-benzyloxy-psilocin which was debenzylated to form 3H-psilocin. (author)

  14. Bound residues of 14C-carbofuran in soil

    International Nuclear Information System (INIS)

    Mineralization of 14C-carbofuran (2,3 dihydro-2,2-dimethyl-7-benzofuranyl-methylcarbamate) to 14CO2 as well as the formation of extractable and bound 14C-residues in clay loam soil were investigated under laboratory conditions. The 14C-carbofuran rapidly mineralized to 14CO2 and, after 20 days of incubation, 35.6% of the applied 14C was lost as 14CO2. The steady decrease of extractable 14C-residues was accomplished by a corresponding increase of bound 14C-residues over a 20-day incubation period. At the end of the experiment, the extractable and bound 14C-residues amounted to 7% and 59%, respectively, of applied radiocarbon. The soil containing bound 14C-residues was fractionated into humic substances. The humic acid, fulvic acid and humin fractions contained 22.39%, 26.04% and 17.56%, respectively, of the applied radiocarbon. The amount of 14C in microbial biomass was 15%. (author)

  15. Metabolism of progesterone-4-14C in organ cultures of fetal adrenal glands in the human being

    International Nuclear Information System (INIS)

    1. In 72 hours of incubation in two subsequent cultures, progesterone-4-14C was converted into different corticosteroids and androgenes by using explants of the adrenal glands in organ cultures, which were taken from a male fetus with a crown-to-rump length of 8.5 cm. In the most cases the water-dilutable metabolites are steroidsulfates. 2. The following individual progesterone metabolites were found: 17α-hydroxyprogesterone-4-14C, 16α-hydroxyprogesterone-4-14C, corticosterone-4-14C, cortisole-4-14C, cortisone-4-14C, androstendione-4-14C, and 11β-hydroxyandrostendione-4-14C. 3. These steroides let appear possible the presence and efficacy of the following enzyme systems: 17α-hydroxylase, 16α-hydroxylase, 21-hydroxylase, 11β-hydroxylase, 11β-hydroxysteroide-dehydrogenase, and Csub(17-20) desmolase. 4. Calculations of our dates by the analogue computer, which are present by now, apparently seem to render possible the kinetic of the corticosteroide biosynthesis in the tissue of fetal adrenal glands by organ cultures, because under the present conditions incubations can be carried out for considerably longer periods than by cell fractions, cell homogenates, and organ sections. (orig.)

  16. Structure of T=2 24Ne from 14C on 14C

    International Nuclear Information System (INIS)

    The 14C(14C,α) reaction at 22 MeV was used to study T=2 24Ne. Charged particles were detected with a Si detector telescope at 0 deg., and γ transitions in coincidence were detected with an array of three Compton-suppressed 'clover' detectors and seven Compton-suppressed single Ge crystals. The α-γ and α-γ-γ coincidence data were analyzed to study the structure of 24Ne. Twenty-two new γ lines were assigned to 14 new levels. Angular distribution measurements provided spin assignments and restrictions to a number of levels. Likely candidates were found for the lowest 5+ and 6+ levels. All but one of the 12 states predicted to lie below 6 MeV by shell model calculations using the universal s-d interaction were observed. The rms deviation in excitation energies among these is 190 keV, and there is a tendency for the observed levels to lie somewhat higher than the predicted ones. A comparison of the structure of 24Ne with its neighbors suggests a significant shell gap above the νd5/2 orbital in agreement with the large d5/2-s1/2 gap implied by the effective single-particle energies in the universal s-d shell model interaction

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

    International Nuclear Information System (INIS)

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

  18. Behaviour of (14)C-sulfadiazine and (14)C-difloxacin during manure storage.

    Science.gov (United States)

    Lamshöft, Marc; Sukul, Premasis; Zühlke, Sebastian; Spiteller, Michael

    2010-03-01

    The persistence of sulfadiazine, difloxacin, and their metabolites has been investigated in stored manure. The manure collected from sulfadiazine ((14)C-SDZ) and difloxacin ((14)C-DIF) treated pigs contained N-acetylsulfadiazine (Ac-SDZ), 4-hydroxy-SDZ (4-OH-SDZ), and sarafloxacin (SARA) as the main metabolites, respectively along with their parent compounds. Manures were stored separately at 10 degrees C and 20 degrees C at various moisture levels. About 96-99% of the radioactivity remained in extractable parent compounds and their metabolites after 150d of storage. The formation of non-extractable residue and the rate of mineralization were both negligible in manure containing SDZ and DIF. During storage SDZ concentration increased as a result of the deacetylation of Ac-SDZ, whose concentration decreased proportionally. Hence the environmental effects may be underestimated if the parent compound alone is considered for environmental risk assessment. About 11% and 14% of 4-OH-SDZ were lost after 20 and 40d of storage; thereafter its concentration increased relatively, highlighting hydroxylation of SDZ. DIF degraded very slowly (7% loss after 150d) during the storage of manure; in contrast the concentration of SARA decreased rapidly (72-90% loss after 150d). Dilution of manure and storage at higher temperatures for a reasonable period of time enhanced the rate of reactions of SDZ, DIF and their related metabolites. PMID:20022355

  19. Behaviour of {sup 14}C-sulfadiazine and {sup 14}C-difloxacin during manure storage

    Energy Technology Data Exchange (ETDEWEB)

    Lamshoeft, Marc; Sukul, Premasis; Zuehlke, Sebastian [Institute of Environmental Research (INFU), TU Dortmund, Otto-Hahn-Strasse 6, D-44227 Dortmund (Germany); Spiteller, Michael, E-mail: M.Spiteller@infu.uni-dortmund.de [Institute of Environmental Research (INFU), TU Dortmund, Otto-Hahn-Strasse 6, D-44227 Dortmund (Germany)

    2010-03-01

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

  20. Low-level 14C methane oxidation rate measurements modified for remote field settings

    Science.gov (United States)

    Pack, M. A.; Pohlman, J.; Ruppel, C. D.; Xu, X.

    2012-12-01

    Aerobic methane oxidation limits atmospheric methane emissions from degraded subsea permafrost and dissociated methane hydrates in high latitude oceans. Methane oxidation rate measurements are a crucial tool for investigating the efficacy of this process, but are logistically challenging when working on small research vessels in remote settings. We modified a low-level 14C-CH4 oxidation rate measurement for use in the Beaufort Sea above hydrate bearing sediments during August 2012. Application of the more common 3H-CH4 rate measurement that uses 106 times more radioactivity was not practical because the R/V Ukpik cannot accommodate a radiation van. The low-level 14C measurement does not require a radiation van, but careful isolation of the 14C-label is essential to avoid contaminating natural abundance 14C measurements. We used 14C-CH4 with a total activity of 1.1 μCi, which is far below the 100 μCi permitting level. In addition, we modified field procedures to simplify and shorten sample processing. The original low-level 14C-CH4 method requires 6 steps in the field: (1) collect water samples in glass serum bottles, (2) inject 14C-CH4 into bottles, (3) incubate for 24 hours, (4) filter to separate the methanotrophic bacterial cells from the aqueous sample, (5) kill the filtrate with sodium hydroxide (NaOH), and (6) purge with nitrogen to remove unused 14C-CH4. Onshore, the 14C-CH4 respired to carbon dioxide or incorporated into cell material by methanotrophic bacteria during incubation is quantified by accelerator mass spectrometry (AMS). We conducted an experiment to test the possibility of storing samples for purging and filtering back onshore (steps 4 and 6). We subjected a series of water samples to steps 1-3 & 5, and preserved with mercuric chloride (HgCl2) instead of NaOH because HgCl2 is less likely to break down cell material during storage. The 14C-content of the carbon dioxide in samples preserved with HgCl2 and stored for up to 2 weeks was stable

  1. Synthesis of [3-14C]-L-tryptophan and 5'-hydroxy-[3-14C]-L-tryptophan

    International Nuclear Information System (INIS)

    The synthesis of selectively labeled [3-14C]-L-tryptophan and its derivative 5'-hydroxy-[3-14C]-L-tryptophan using chemical and multienzymatic methods is reported. The key intermediate for this synthesis, 3-14C]-DL-alanine was obtained from 14CH3I as a result of its condensation with N- (diphenylmethylene)glycine tert-butyl ester. Next, the mixture containing [3-14C]-DL-alanine, indole or 5-hydroxyindole has been converted to [3-14C]-L-tryptophan or 5'-hydroxy-[3-14C]-L-tryptophan, respectively, in a one-pot multienzymatic reaction using four enzymes: -amino acid oxidase, catalase, glutamic-pyruvic transaminase and tryptophanase. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-02-15

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

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

    International Nuclear Information System (INIS)

    Three types of culture experiments using paddy rice (Oryza sativa L.) were performed to examine root-uptake of 14C in the form of acetic acid: double pot experiment (hydroponics), wet culture experiment (submerged sand medium), and chamber experiment (hydroponics and submerged sand medium). The 14C radioactivity in the plant, mediums, and atmospheric carbon dioxide (14CO2) in the chamber were determined, and the distribution of 14C in the plant was visualized using autoradiography. In the double pot experiment, the shoot of the plant and the lower root which was soaked in the culture solution had 14C radioactivity, but the upper root which did not have contact with the solution had none. There were also 14C radioactivity in the grains and roots in the wet culture experiment. Results of the chamber experiment showed that 14CO2 gas was released from the culture solution in both types of cultures. Results indicated that the 14C-acetic acid absorbed by rice plant through its root would be very small. Most of the 14C-acetic acid was transformed into gaseous forms either in the culture solution or rhizosphere. A relatively longer time would be needed to assimilate 14C derived from acetic acid to grain parts after it was once absorbed by the shoot through the root. Availability of 14C for the plant in sand culture was considered to be decreased compared with that for the plant in the hydroponics experiment. It was suggested that rice plant absorbed and assimilated 14C through the plant roots not because of uptake of 14C-acetic acid but because of uptake of 14C in gaseous forms such as 14CO2.

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

    Science.gov (United States)

    Prastowo, Erwin; Grootes, Pieter; Nadeau, Marie

    2016-04-01

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

  5. The use of 14C ethanolamine as a precursor

    International Nuclear Information System (INIS)

    Two new 2 chloroethyl nitrosoureas were labelled on two positions by 14C starting from Na14CN and using 14C ethanolamine as intermediate, i.e. on the carbon 2 of the 2 chloro ethyl group and on the carbon 2 of the cysteamine part. (author)

  6. 14C ages of Omuroyama volcano, Izu Peninsula

    International Nuclear Information System (INIS)

    A partly carbonized wood trunk was discovered below the Omuroyama tephra covered by a lava, and it was dated to be 3,700±100 y. B.P., by the benzene liquid scintillation method for radiocarbon age determination. We have investigated the circumstance of the discovery of the wood sample based on an interview of the person who collected the sample during his operation of building construction. According to him, the wood specimen was found at 1.5-2 m depth beneath the ground level when the operator removed the massive blackish lava block. This specimen was laid down covered by black sandy pebbles. The size of the wood trunk was 105 cm long and 45 cm and 35 cm along wide and short diameter, respectively. We also revealed the burial environment of the wood to be related with the Omuroyama tephras and lava flow, based on our volcanostratigraphic observation of the surrounding area. The tephras covering the trunk were identified as the Omuroyama tephra B, C, and D, which were defined by Koyano et al. (1996) around this area, and these tephras were covered by the Omuroyama lava flow II (Koyano et al., 1996). The wood trunk was mostly fresh and only its branch was burned. It can be estimated that the trunk has been preserved surrounded by ground water, since several tons of ground water gushed out when the aquifer was opened for construction. On this context, this trunk was buried at the early stage of the volcanism of Omuroyama volcano covered by the tephras, and later also covered by the Omuroyama lava II. We can not conclude that the burned branch is ascribed to direct burning by the Omuroyama lava flow II but this 14C dating resultant is also concordant all archaeological evidences reported. (author)

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

    International Nuclear Information System (INIS)

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

  8. Radiocarbon 14C differentiation of sparkling and carbonated wines

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  10. Origin and extent of atmospheric 14C variations during the past 10,000 years

    International Nuclear Information System (INIS)

    Lake sedimentation rates are, in general, variable, and changes in rate are normally local and not correlative timewise over large areas, especially as between different lakes. A possible exception is a synchronous change in sedimentation rate due to a world-wide climatic change. In addition, changes in the 14C time scale due to long-term variations in atmospheric 14C content may add 'fictitious' changes in sedimentation rate calculated from 14C dates. All sedimentary processes in suitable basins should register synchronously these fictitious changes (signal) but should not record synchronously other rate changes of local nature (noise). It is therefore possible, in principle, to separate changes due to variations in 14C time scale or a world-wide climatic change from changes due to other variations by analysing a sufficiently large number of sedimentary events and removing the synchronous variations in sedimentation rate. This study reports the detailed 14C analysis of sediments flooring three lakes: Rogers Lake, Conn., in the United States of America, Lake Victoria in Africa, and Lake Yueh Tan in Formosa. The lakes were chosen from widely different latitudes to avoid synchronous variations induced by local climatic changes. Two of the lakes, Rogers Lake and Lake Victoria, show a surprisingly steady sedimentation rate. When corrected for changes in time scale, known from tree-ring studies, the absolute sedimentation rates for both lakes appears to have been constant for the past 6000 calendar years. The sedimentation rate study affirms the change in time scale observed in 14C ages of tree rings and Egyptian samples of known ages around 2500 B. P. In addition, important synchronous changes are lacking in the sedimentation rates of all three lakes between 2500 and 10,000 years B. P. This implies that there have been neither important variations in sedimentation rates due to world-wide climatic changes nor drastic changes in the 14C time scale during this time span

  11. Impact of atmospheric 14C to the karst environment

    International Nuclear Information System (INIS)

    Naturally cosmic-ray produced radiocarbon 14C is a part of the CO2 cycle and through the atmosphere-biosphere-hydrosphere exchange process it has been introduced to the environment. Anthropogenic disturbance of the natural 14C activity caused by nuclear tests, nuclear power plants and also by fossil fuel combustion has been recorded in the atmospheric CO2. The karst environment including water, carbonate sediment and soil, where exchange processes within the CO2-HCO3 -CaCO3 system play an important role, is very sensitive to any change in the atmosphere and response to the contamination is very fast. 14C activity of atmospheric CO2 has been continuously measured in monthly samples in Zagreb area since 1983. Seasonal variations have been observed, as well as steady decrease of yearly mean values. Influence of fossil fuel combustion in the city area during winter months was also observed. Few examples of isotopic study in karst environment in Croatia and Slovenia will be presented: 1) The influence of atmospheric 14C activity to the recent carbonate precipitated in the surface water in form of tufa in the Plitvice Lakes, Korana, Krka and Zrmanja rivers in Croatia, and Krka river in Slovenia; 2) 14C activity in recent speleothems from several caves in Croatia and Postojna Cave in Slovenia; 3) Distribution of 14C activity in the surface soil in Plitvice Lakes and Postojna areas; 4) 14C activity of atmospheric CO2 inside and outside the Postojna Cave, 5) 14C activity in recent plants (aquatic and terrestrial) and shells. The stable isotopes δ 13C and δ 18O for some of the samples above will be presented too. Distribution of 14C in the karst environment will be discussed and compared with 14C activity of atmospheric CO2

  12. Distribution of 14C, 90Sr and 228Th in an elephant tusk

    International Nuclear Information System (INIS)

    The period of date of death of an elephant can be assessed by analyzing four different radionuclides, 14C, 90Sr, 228Th and 232Th in its ivory. These nuclides are supposed to have variing concentrations at different parts of a tusk. The reason is the procedure of growth which takes place at the butt-site of a tusk. Therefore the site of sampling could have a big influence on the assessed date of death. However, to find out if the position of sampling is important a complete tusk was analyzed regarding the distribution of these nuclides. Results show that the concentration activity of 14C and 228Th varies in different parts of a tusk. The activity concentration of 90Sr is very similar in all analyzed parts. The conclusion is that sampling at the butt of a tusk is recommended for age assessment. (author)

  13. Helicobacter pylori infection studies using 14C UBT method

    International Nuclear Information System (INIS)

    Carbon 14 (14C) is a naturally occurring radioactive isotope of carbon. The half-life of 14C is about 5,730 years, and it decays by emitting a low energy beta (â) particle of mean energy 49 KeV. The biological half life of 14C is 10 to 12 days. 14C is present in the environment and in all organic materials and behaves in the environment in the same manner as other carbon isotopes. In medicine, 14C can be injected to study abnormalities of metabolism that underlie diabetes, gout, anaemia and acromegaly (adult 'gigantism'), and for diagnosis of Helicobacterpylori (H pylori), The discovery H Pylori by Warren and Marshall in 1982 changed the approach to treat peptic ulcer disease (PUD), Since then H pylori has been the focus of clinical research and debate. The causal relationship between H pylori infection and chronic gastritis is well established, H pylori infection is one of the most common human infections worldwide. This organism has been shown to infect over half of the world's population. By the application of radiation much progress has been made worldwide in the field of medicine. This article presents the application of 14C Urea Breath Test (14C UBT) for the diagnosis of the H pylori bacteria which present in the stomach and duodenum, 14C UBT relies on the urease activity of H pylori to detect the presence of active infection. Board of Radiation and Isotope Technology (BRIT), Mumbai has developed 14C UBT method and already in regular practice in many hospitals across the country. Orally administered 14C urea will be hydrolyzed into ammonia (NH4) and 14C labelled carbon dioxide (14CO2). The presence of a significant amount of (14CO2) in the exhaled breath indicates active H pylori infection. 14C UBT is relatively inexpensive, is easy to perform, and does not require endoscopy. 14C UBT has proved to be one of the most accurate methods for assessing H pylori status. The ionizing radiation dose involved in this test is extremely low, much lower than the

  14. 14C-age tracers in global ocean circulation models

    Science.gov (United States)

    Koeve, W.; Wagner, H.; Kähler, P.; Oschlies, A.

    2015-07-01

    The natural abundance of 14C in total CO2 dissolved in seawater (DIC) is a property applied to evaluate the water age structure and circulation in the ocean and in ocean models. In this study we use three different representations of the global ocean circulation augmented with a suite of idealised tracers to study the potential and limitations of using natural 14C to determine water age, which is the time elapsed since a body of water has been in contact with the atmosphere. We find that, globally, bulk 14C-age is dominated by two equally important components, one associated with ageing, i.e. the time component of circulation, and one associated with a "preformed 14C-age". The latter quantity exists because of the slow and incomplete atmosphere-ocean equilibration of 14C particularly in high latitudes where many water masses form. In the ocean's interior, preformed 14C-age behaves like a passive tracer. The relative contribution of the preformed component to bulk 14C-age varies regionally within a given model, but also between models. Regional variability in the Atlantic Ocean is associated with the mixing of waters with very different end members of preformed 14C-age. Here, variations in the preformed component over space and time mask the circulation component to an extent that its patterns are not detectable from bulk 14C-age. Between models, the variability of preformed 14C-age can also be considerable (factor of 2), related to the combination of physical model parameters, which influence circulation dynamics or gas exchange. The preformed component was found to be very sensitive to gas exchange and moderately sensitive to ice cover. In our model evaluation, the choice of the gas-exchange constant from within the currently accepted range of uncertainty had such a strong influence on preformed and bulk 14C-age that if model evaluation would be based on bulk 14C-age, it could easily impair the evaluation and tuning of a model's circulation on global and regional

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

    International Nuclear Information System (INIS)

    The myo-inositol-14C, phytic acid-14C and ferric phytate-14C compounds were incubated in an andosol soil at 70% of the field capacity and at 36.5 deg C during twelve days. These compounds suffered a microbian oxidation at 14CO2 of 61.0, 1.9 and 0% respectively. The fixation of the phytic acid-14C was observed through the fast decrease in the metabolism, due to the formation of complexes with the Fe and Al (phytates). The myo-inositol-14C metabolism was reduced by a factor of nine at the second incubation day. The following mechanisms were observed in the myo-inositol metabolism: (i) adsorption of the inositol by the soil minerals, (ii) adsorption by humic acids, (iii) myo-inositol phosphorylation and (iv) epimerization of myo-inositol to chiro-inositol. It was found that the (i) and (ii) formation depends on the soil microbian activity. The (i), (ii) and (iii) interactions were considered as possible mechanisms for the inhibition of the myo-inositol microbian oxidation. The inhibition of the myo-inositol oxidation through adsorption or phosphorylation is considered as a chemical blockade for the hydroaxial group, avoiding this way a microbian oxidation stereospecific of this hydroxil group. (author)

  16. Determining the biomass fraction of mixed waste fuels: A comparison of existing industry and {sup 14}C-based methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Muir, G.K.P., E-mail: Graham.Muir@glasgow.ac.uk [SUERC Radiocarbon Laboratory, Scottish Universities Environmental Research Centre (SUERC), Rankine Avenue, East Kilbride G75 0QF, Scotland (United Kingdom); Hayward, S. [Stopford Energy and Environment, The Gordon Manley Building, Lancaster University, Lancaster LA1 4YQ, England (United Kingdom); Tripney, B.G.; Cook, G.T.; Naysmith, P. [SUERC Radiocarbon Laboratory, Scottish Universities Environmental Research Centre (SUERC), Rankine Avenue, East Kilbride G75 0QF, Scotland (United Kingdom); Herbert, B.M.J. [Stopford Energy and Environment, The Gordon Manley Building, Lancaster University, Lancaster LA1 4YQ, England (United Kingdom); Garnett, M.H [NERC Radiocarbon Facility, Scottish Enterprise Technology Park, Rankine Avenue, East Kilbride G75 0QF, Scotland (United Kingdom); Wilkinson, M. [Stopford Energy and Environment, The Gordon Manley Building, Lancaster University, Lancaster LA1 4YQ, England (United Kingdom)

    2015-01-15

    Highlights: • Compares industry standard and {sup 14}C methods for determining bioenergy content of MSW. • Differences quantified through study at an operational energy from waste plant. • Manual sort and selective dissolution are unreliable measures of feedstock bioenergy. • {sup 14}C methods (esp. AMS) improve precision and reliability of bioenergy determination. • Implications for electricity generators and regulators for award of bio-incentives. - Abstract: {sup 14}C analysis of flue gas by accelerator mass spectrometry (AMS) and liquid scintillation counting (LSC) were used to determine the biomass fraction of mixed waste at an operational energy-from-waste (EfW) plant. Results were converted to bioenergy (% total) using mathematical algorithms and assessed against existing industry methodologies which involve manual sorting and selective dissolution (SD) of feedstock. Simultaneous determinations using flue gas showed excellent agreement: 44.8 ± 2.7% for AMS and 44.6 ± 12.3% for LSC. Comparable bioenergy results were obtained using a feedstock manual sort procedure (41.4%), whilst a procedure based on selective dissolution of representative waste material is reported as 75.5% (no errors quoted). {sup 14}C techniques present significant advantages in data acquisition, precision and reliability for both electricity generator and industry regulator.

  17. Determining the biomass fraction of mixed waste fuels: A comparison of existing industry and 14C-based methodologies

    International Nuclear Information System (INIS)

    Highlights: • Compares industry standard and 14C methods for determining bioenergy content of MSW. • Differences quantified through study at an operational energy from waste plant. • Manual sort and selective dissolution are unreliable measures of feedstock bioenergy. • 14C methods (esp. AMS) improve precision and reliability of bioenergy determination. • Implications for electricity generators and regulators for award of bio-incentives. - Abstract: 14C analysis of flue gas by accelerator mass spectrometry (AMS) and liquid scintillation counting (LSC) were used to determine the biomass fraction of mixed waste at an operational energy-from-waste (EfW) plant. Results were converted to bioenergy (% total) using mathematical algorithms and assessed against existing industry methodologies which involve manual sorting and selective dissolution (SD) of feedstock. Simultaneous determinations using flue gas showed excellent agreement: 44.8 ± 2.7% for AMS and 44.6 ± 12.3% for LSC. Comparable bioenergy results were obtained using a feedstock manual sort procedure (41.4%), whilst a procedure based on selective dissolution of representative waste material is reported as 75.5% (no errors quoted). 14C techniques present significant advantages in data acquisition, precision and reliability for both electricity generator and industry regulator

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  20. 14C in the deep water of the east Atlantic

    International Nuclear Information System (INIS)

    The renewal of east Atlantic deep water and its large-scale circulation and mixing have been studied in observed distributions of temperature, silicate, ΣCO2, and 14C. 14C variations in northeast Atlantic deep water below 3500m depth are small. Δ14C values range from - 100 per thousand to - 125 per thousand. 14C bottom water concentrations decrease from Δ14C = -117 per thousand in the Sierra Leone Basin to Δ14C = -123 per thousand in the Iberian Basin and are consistent with a mean northward bottom water flow. The characteristic of the water that flows from the west Atlantic through the Romanche Trench into the east Atlantic was determined by inspection of theta/Δ14C and theta/SiO2 diagrams. A mean potential temperature of theta = 1.50 +/- .050C was found for the inflowing water. A multi-box model including circulation, mixing, and chemical source terms in the deep water has been formulated. Linear programming and least-squares techniques have been used to obtain the transport and source parameters of the model from the observed tracer fields. Model calculations reveal an inflow through the Romanche Trench from the west Atlantic, which predominates over any other inflow (5 +/- 2) Sv (potential temperature 1.500C), a convective turnover of (150 +/- 50) years and a vertical apparent diffusivity of (4 +/- 1) cm2/s. Chemical source terms are in the expected ranges

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

    International Nuclear Information System (INIS)

    There is need for an improved test of human ability to assimilate dietary vitamin B12. Assaying and understanding absorption and uptake of B12 is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry (AMS) is uniquely suited for assessing absorption and kinetics of 14C-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of carbon-14 (14C) in microliter volumes of biological samples, with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B12 in the range of normal dietary intake. The B12 used was quantitatively labeled with 14C at one particular atom of the DMB moiety by exploiting idiosyncrasies of Salmonellametabolism. In order to grow aerobically on ethanolamine, S. entericamust be provided with either pre-formed B12 or two of its precursors: cobinamide and dimethylbenzimidazole (DMB). When provided with 14C-DMB specifically labeled in the C2 position, cells produced 14C-B12 of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 mg, 2.2 KBq/59 nCi) of purified 14C-B12 was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B12 assimilation

  2. Aspects of the metabolism of U-14C arginine, U-14C histidine and U-14C lysine by adult female Glossina morsitans during pregnancy

    International Nuclear Information System (INIS)

    U-14C arginine, U-14C histidine or U-14C lysine was injected into haemolymph of pregnant female Glossina morsitans. Radioactivity was detected in the post-parturient female and its larval offspring mostly in arginine or histidine, but in the case of lysine injection radioactivity was detected in the two life stages in lysine lipids and a range of nonessential amino acids. The pattern of radioactivity in the developing oocyte and larva was related to growth characteristics of these young stages. Whereas arginine and histidine were mostly excreted unchanged, lysine derived radioactivity was detected in the excreted uric acid and expired carbon dioxide; radioactivity in such products was greater in early than late pregnancy. (author)

  3. Thermoluminescence dating of late-glacial sand sediments

    International Nuclear Information System (INIS)

    Ten Late-Glacial sediments were dated by the regeneration method combined with the plateau criteria. The thermoluminescence (TL) dates were compared with independent dates assessed indirectly by radiocarbon dating or varve chronology. For comparison, the 14C dates were calibrated by adding 1000 yr to the conventional results. Eight TL dates agreed with the 14C dates within the uncertainty of the TL dates (± 1 ka), one was overestimated and one underestimated. (author)

  4. Synthesis of 3H and 14C labelled changrolin

    International Nuclear Information System (INIS)

    3 kinds of [14C] and [3H] changrolin labelled at different positions (I, II, III) were prepared. The synthesis of I is as follows: (Scheme 1): Heating 5-bromoanthranilic acid with formamide yielded IV, which on heating with POCl3 gave V. Condensation of V with 4-aminophenol and Mannich reaction produced 6-bromochangrolin (VI). Catalytic dehalogenation of VI with tritium gas gave I. The synthesis of II was started from (14C) formamide and anthranilic acid. Labelled 4-chloroquine obtained was condensed with Mannich base (VII) directly (Scheme 2). III was prepared by 1 step with (14C) formaldehyde (Scheme 1)

  5. 14C-carbaryl residues in cotton seed products

    International Nuclear Information System (INIS)

    14C-Methyl and 14C-ring-labelled carbaryl were used to study the magnitude and fate of the insecticide residues in cotton seed products and in the plant. 14C-Residues were found to be 0.08-0.09, 0.23-0.30 and 0.05 ppm in the seed, oil and cake respectively. In the oil, the residue was resolved into four compounds two of which were identified as carbaryl and 1-naphthol. Residues taken up from the soil did not exceed 0.3 ppm after the first week and declined to 0.1 ppm after five weeks. (author)

  6. C-14 bomb peak dating of human DNA samples at the microgram level

    International Nuclear Information System (INIS)

    Radiocarbon (14C, t1/2 = 5700 ± 30 years) is probably the radionuclide with the most versatile applications, spanning from archaeology to geoscience and medicine. Many of these applications are finally limited by the minimum amount of carbon in which the isotopic ratio 14C/12C can be measured. The required carbon sample size has dramatically decreased with the development of Accelerator Mass Spectrometry (AMS), typically from gram amounts for the classical beta counting method to about 1 milligram for AMS. The current work presents a further reduction into the few-μg carbon range. This means a decrease by a factor of one million compared to classical beta counting and is essential for the field of retrospective birth dating of human cells by means of radiocarbon from above-ground nuclear weapons testing between 1955 and 1963. The determination of 14C levels in genomic DNA can be used to retrospectively establish the birth date of cells in the human body. The main motive of the current work was to reduce the amount of carbon required for reliable 14C measurements to such an extent that investigations of neurons of particularly interesting small sections of the human brain (e.g. the olfactory bulb, bulbus olfactorius) were possible. In-depth investigations and development of 14C AMS sample preparation and measurement methods for μg-size DNA samples were carried out in close collaboration with the Department of Cell and Molecular Biology of the Karolinska Institute in Stockholm. As the most significant result, 14C measurements of 4.6 μg carbon DNA samples were performed with an overall precision of 2.3%. This allowed to study neurogenesis in the human olfactory bulb, which turned out to take place primarily at birth. Assuming throughout life a constant annual renewal rate of neurons in the human olfactory bulb, an upper limit of 0.34% for the renewal rate (95% confidence) was determined. At the Vienna Environmental Research Accelerator (VERA) the μg carbon

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

    International Nuclear Information System (INIS)

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

  8. 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)

    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)

  9. Determination of 14C content in fermentation alcohols

    International Nuclear Information System (INIS)

    The measuring of activity in 14C of ethylic alcohol permits to distinguish fermentation alcohol from synthetic alcohol. This activity is used to determine the corresponding percentages of these alcohols in cases of mixture

  10. Determination of phagocytosis in periodontitis postjuvenilis using 14C

    International Nuclear Information System (INIS)

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

  11. Patient risk of 14C-urea breath test

    International Nuclear Information System (INIS)

    Helicobacter Pylori bacteria infection is determined by activity measurement of the exhaled 14C-carbon dioxide formed from 14C-urea in stomach. About 37 kBq of capsulated 14C -urea is administered to the patient. Because 14C is a weak beta emitter, patients receive certain radiation dose. This could be the only drawback of this method. Because of that in this paper the effective dose has been determined. On that basis the patient risk has been estimated. The results show that the patient effective dose is at the level of the daily background radiation. So, from the radiation protection point of view this method is very safe. Including other excellent performances of the method like sensitivity, selectivity, noninvasivity, fastness and low costs, it could be recommended in diagnosis and eradication of Helicobacter Pylori infections. (author)

  12. Residues of 14C-cyolane in cottonseed products

    International Nuclear Information System (INIS)

    The systemic insecticide cyolane [2-(0,0-diethylphosphoryl)-imino-1,3-dithiolane] was prepared from 14C-ethanol, phosphorus oxychloride and 2-amino-1,3-dithiolane. Cotton plants were treated with two applications of the insecticide under conditions of local agricultural practice. 14C-residues in the crude oil and cake of the harvested cotton seeds amounted to 1.63 and 0.014 mg/kg respectively. About 50% of the 14C-activity present in the crude oil was found to be eliminated by simulated commercial processes used for refining of the oil. Alkali treatment and bleaching removed 16% and 25% of the radioactive residues respectively. Winterization of the bleached oil at 5-70C for 3 days effected a further elimination of 13%. 14C-residues in the cotton seed products and in the samples of the refined oil were characterized and the main constituents identified using chromatographic techniques. (author)

  13. 14C-age tracers in global ocean circulation models

    Directory of Open Access Journals (Sweden)

    W. Koeve

    2014-10-01

    Full Text Available The natural abundance of 14C in total CO2 dissolved in seawater is a property applied to evaluate the water age structure and circulation in the ocean and in ocean models. In this study we use three different representations of the global ocean circulation augmented with a suite of idealised tracers to study the potential and limitations of using natural 14C to determine water age, the time elapsed since a body of water had contact with the atmosphere. We find that, globally, bulk 14C-age is dominated by two equally important components, one associated with aging, i.e. the time component of circulation and one associated with a "preformed 14C-age". This latter quantity exists because of the slow and incomplete atmosphere/ocean equilibration of 14C in particular in high latitudes where many water masses form. The relative contribution of the preformed component to bulk 14C-age varies regionally within a given model, but also between models. Regional variability, e.g. in the Atlantic Ocean is associated with the mixing of waters with very different end members of preformed 14C-age. In the Atlantic, variations in the preformed component over space and time mask the circulation component to an extent that its patterns are not detectable from bulk 14C-age alone. Between models the variability of age can also be considerable (factor of 2, related to the combinations of physical model parameters, which influence circulation dynamics, and gas exchange in the models. The preformed component was found to be very sensitive to gas exchange and moderately sensitive to ice cover. In our model evaluation exercise, the choice of the gas exchange constant from within the current range of uncertainty had such a strong influence on preformed and bulk 14C-age that if model evaluation would be based on bulk 14C-age it could easily impair the evaluation and tuning of a models circulation on global and regional scales. Based on the results of this study, we propose

  14. Use of 14 c in the assessment of source-sink relationship in plants Of wheat during grain filling

    International Nuclear Information System (INIS)

    How source-sink relationships in wheat differ in tropic and temperate zones are important environmental parameters in understanding physiological factors limiting grain filling under field conditions. The aim of this investigation was to assess the time-course of source-sink interactions in wheat after anthesis under Cuban field conditions. For this purpose, plants of wheat, cultivar Cuba C-204, were sown at six dates in the field. The patterns of partitioning of 14 C-photoassimilates between organs and between ethanol and perchloric acid soluble fractions in the kernels, 24 h after feeding the flag leaf blade with 14 CO2, were investigated on different occasions after anthesis to evaluate the source-sink balance. There was a high increase in the proportion of 14 C converted into starch in the kernels during the first 15 days of grain filling. Throughout the grain filling phase the proportion of total 14 C fixed partitioned to the grains increased, whereas the per cent allocated to the internodes decreased. The patterns of partitioning of 14 C-photoassimilates differed between sowing dates. The differences in the accumulation and conversion of 14 C-photoassimilates in the kernels were mainly at the initial phase of grain filling. During this phase the proportion of 14 C incorporated into starch in the kernels positively correlated (P<0.01) with the proportion of the label partitioned to the grains and negatively (P<0.01) with 14 C accumulation in the peduncle and penultimate internodes, supporting that accumulation of 14 C in the stem was in close relationship with the uptake capacity of the grains. The lack of significance at two later measurements indicates that, generally, there was a change from sink- to source-limited situation. We concluded, that in most sowings, the supply limited grain filling mainly during the second half of this phase, whereas during the first days after anthesis the grain filling was sink limited

  15. Radiochemical synthesis of 14C-labelled pesticides

    International Nuclear Information System (INIS)

    Radioisotopic derivatives of pesticides labelled with either 14C or tritium are indispensable experimental tools for toxicology or metabolism studies required for registration of new compounds. The radiochemical synthetic pathways leading to the preparation of 14C-labelled pesticides of high specific activity, good chemical/radiochemical yield, and high radiochemical purity are presented for three groups of pesticides; triazines, aryl-haloids, and organometallic compounds. (N.T.). 10 refs., 1 tab

  16. Preparation of 14C-catechins by tea cell culture

    International Nuclear Information System (INIS)

    The preparation of 14C labelled catechins was studied by feeding 14C labelled precursor to tea cultured cells. Two labelled precursors were tested and their effects were compared. The dynamics of absorption and transformation of fed precursors were analyzed and the effects of pre-culture as well as UV light pretreatment on product labelling rate were evaluated. Product analysis was also made by HSCCC and HPLC techniques

  17. 14C-Metampicillin stability in several physiological sera

    International Nuclear Information System (INIS)

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

  18. Synthesis of [14C]-labelled dihydropyridine calcium channel entry blockers: nicardipine-[4[14C] and RS-93522-[4-14C

    International Nuclear Information System (INIS)

    The Hantzsch synthesis has been applied to the general preparation of 4-aryl-dihydropyridines labelled in the metabolically stable 4-position of the dihydropyridine ring. The synthesis is based on the preparation of a key common intermediate, m-nitrobenzaldehyde-[formyl-14C], in high yield from Ba14CO3. (author)

  19. 41Ca, 14C and 10Be concentrations in coral sand from the Bikini atoll

    International Nuclear Information System (INIS)

    Activation measurements of materials exposed to nuclear bomb explosions are widely used to reconstruct the neutron flux for retrospective dosimetry. In this study the applicability of coral CaCO3 as a biogenic neutron fluence dosimeter is tested. The long-lived radioisotopes 41Ca, 14C and 10Be, which had been produced in nuclear bomb explosions, are measured in several coral sand samples from the Bikini atoll at the 600 kV and 200 kV AMS facilities of ETH Zurich. Elevated concentrations of all studied isotopes are found in a sample from the crater that was initially formed by the high-yield nuclear explosion Castle Bravo in 1954 and that had been used as site for several tests afterward. The observed 14C concentration is considered too large to originate from neutron irradiation of CaCO3 alone. The relatively low concentration of 10Be found in the crater sample indicates that production of 10Be during nuclear bomb testing is generally minor. A simple neutron fluence reconstruction is performed on basis of the 41Ca/40Ca ratio. - Highlights: • Concentrations of 41Ca, 14C and 10Be were determined at the Bikini atoll. • The radionuclides were measured via low-energy Accelerator Mass Spectrometry. • Neutron fluences in the coral CaCO3 target were estimated at the test site. • A global signal of anthropogenic 10Be in natural archives cannot be expected

  20. Lymphokine-induced uptake of [14C]glucosamine, [14C]glucose, and [3H]leucine by macrophages

    International Nuclear Information System (INIS)

    Lymphokine-activated (LK+) and control (LK-) macrophages were cultured for 66 h and then pulsed with [14C]glucosamine. Uptake of [14C]glucosamine was greater in LK+ than in LK- cultures. If, after 66 h, the medium was replaced with fresh medium and then pulsed with either [14C]glucose or [14C]glucosamine, the uptake of isotope was greatly reduced compared to cultures with no change of medium. However, uptake of both radiolabeled substances was still found to be greater in LK+ cultures than in LK- cultures. Although uptake of both substances was enhanced by lymphokines, the uptake kinetics of each isotope was different. Under similar conditions the uptake of [3H]leucine was not enhanced by lymphokine activation. These data are interpreted to mean that LK+ macrophages are metabolically stimulated and utilize more glucose and glucosamine. The difference in kinetics implies a different utilization by macrophages for each substance

  1. Metabolic Fate of [(14)C]Diuron and [(14)C]Linuron in Wheat (Triticum aestivum) and Radish (Raphanus sativus).

    OpenAIRE

    Pascal-Lorber, Sophie; Alsayeda, Haifaa; Jouanin, Isabelle; Debrauwer, Laurent; Canlet, Cécile; Laurent, François

    2010-01-01

    Metabolism of xenobiotics in plants usually occurs in three phases, phase I (primary metabolism), phase II (conjugation processes), and phase III (storage). The uptake and metabolism of [(14)C]diuron and [(14)C]linuron were investigated in wheat and radish. Seeds were sown in quartz sand and irrigated with a nutrient solution of either radioactive herbicide. Plants were harvested after two weeks, and metabolites were extracted and then analyzed by radio-reverse-high-performance liquid chromat...

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

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

    2008-08-01

    This paper presents the results of a 4-y investigation of 14C in different waste streams of both boiling water reactors (BWRs) and pressurized water reactors (PWRs). Due to the potential impact of 14C on human health, minimizing waste and releases from the nuclear power industry is of considerable interest. The experimental data and conclusions may be implemented to select appropriate waste management strategies and practices at reactor units and disposal facilities. Organic and inorganic 14C in spent ion exchange resins, process water systems, ejector off-gas and replaced steam generator tubes were analyzed using a recently developed extraction method. Separate analysis of the chemical species is of importance in order to model and predict the fate of 14C within process systems as well as in dose calculations for disposal facilities. By combining the results of this investigation with newly calculated production rates, mass balance assessments were made of the 14C originating from production in the coolant. Of the 14C formed in the coolant of BWRs, 0.6-0.8% was found to be accumulated in the ion exchange resins (core-specific production rate in the coolant of a 2,500 MWth BWR calculated to be 580 GBq GW(e)(-1) y(-1)). The corresponding value for PWRs was 6-10% (production rate in a 2,775 MWth PWR calculated to be 350 GBq GW(e)(-1) y(-1)). The 14C released with liquid discharges was found to be insignificant, constituting less than 0.5% of the production in the coolant. The stack releases, routinely measured at the power plants, were found to correspond to 60-155% of the calculated coolant production, with large variations between the BWR units. PMID:18617793

  4. Radiocarbon dating of charred human bone remains preserved in urns excavated from medieval Buddhist cemetery in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshio, E-mail: nakamura@nendai.nagoya-u.ac.j [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Sagawa, Shinichi; Yamada, Tetsuya [Gangoji Institute for Research of Cultural Properties, Nakain, Nara 630-8392 (Japan); Kanehara, Masaaki [School of Science Education, Nara University of Education, Takabatake, Nara 630-8528 (Japan); Tsuchimoto, Norio [Ichinomiya City Museum, Yamato, Ichinomiya 491-0922 (Japan); Minami, Masayo [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Omori, Takayuki [Graduate School of Environmental Studies, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Okuno, Mitsuru [Faculty of Science, Fukuoka University, Jonan, Fukuoka 814-0180 (Japan); Ohta, Tomoko [Center for Chronological Research, Nagoya University, Chikusa, Nagoya 464-8602 (Japan)

    2010-04-15

    For a preliminary test of {sup 14}C dating of cremated human remains, we have collected charred bone and wood-charcoal fragments from cremated remains contained in cinerary urns that had been excavated from medieval Buddhist cemetery at the Hoenji temple in Aichi prefecture, central Japan. More than 230 urn vessels were discovered from the excavated area of ca. 14 m wide and 14 m long. The identification of charred bone or charcoal fragments among the remains was performed by observation of surface appearance, inspection of fine structures by a microscope, bubble formation during the HCl treatments in preparing target material for AMS {sup 14}C dating, carbon and nitrogen contents, delta{sup 13}C and delta{sup 15}N values of the fragments. All {sup 14}C ages obtained for the samples that were identified as charred bone remains were almost consistent with the archeological age estimated based on typological analysis of respective urns. On the other hand, some {sup 14}C ages for the remains identified as wood charcoal, which had been produced from firewood or a wooden coffin during the cremation, were not consistent with archeological estimation, shifting toward older {sup 14}C ages, most probably as the result of old wood effect.

  5. Radiocarbon dating of charred human bone remains preserved in urns excavated from medieval Buddhist cemetery in Japan

    International Nuclear Information System (INIS)

    For a preliminary test of 14C dating of cremated human remains, we have collected charred bone and wood-charcoal fragments from cremated remains contained in cinerary urns that had been excavated from medieval Buddhist cemetery at the Hoenji temple in Aichi prefecture, central Japan. More than 230 urn vessels were discovered from the excavated area of ca. 14 m wide and 14 m long. The identification of charred bone or charcoal fragments among the remains was performed by observation of surface appearance, inspection of fine structures by a microscope, bubble formation during the HCl treatments in preparing target material for AMS 14C dating, carbon and nitrogen contents, δ13C and δ15N values of the fragments. All 14C ages obtained for the samples that were identified as charred bone remains were almost consistent with the archeological age estimated based on typological analysis of respective urns. On the other hand, some 14C ages for the remains identified as wood charcoal, which had been produced from firewood or a wooden coffin during the cremation, were not consistent with archeological estimation, shifting toward older 14C ages, most probably as the result of old wood effect.

  6. Measurement of 14C/12C ratios in plant samples that were affected by the Fukushima nuclear accident

    International Nuclear Information System (INIS)

    In nature, 14C is produced by cosmic ray reactions in the upper atmosphere, and its production is influenced by the flux of cosmic rays. This nuclide is also released into the atmosphere by anthropogenic sources such as nuclear weapons testing and a nuclear accident. The produced 14C immediately becomes 14CO2 and it is absorbed by plants through photosynthesis. Therefore, plants are reflected by atmospheric 14C levels at that time. Although there are many papers reporting the release of several nuclides by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident occurred in March, 2011, it is not clear whether appreciable amounts of 14C were released into the environment due to the accident. In this study, we focus on 14C levels in plant samples collected from several locations in Fukushima Prefecture (Okuma, Namie, Iitate, and Fukushima-city) and examine the possible influence on the 14C revels in plants. Since cedars and pines are evergreen, the leaves should have been contaminated at the time of the accident. We analyzed old leaves, which were grown before the accident, and new leaves, which were grown after the accident. Both old and new leaves were collected in the same branch. In order to compare delta 14C values in leaves collected from Fukushima Prefecture with background values, we have used plant samples collected from remote areas such as Chiba and Niigata Prefectures. The samples were dried, pulverized in a blender and homogenized. Then samples were placed between copper oxide wires in a quarts tube, burned and oxidized. The produced CO2 mixed gases were purified in a vacuum line. To prepare a graphite target for AMS, the purified CO2 was reduced. 14C/12C ratio in the graphite was measured by AMS at the University of Tokyo or Japan Atomic Energy Agency. Analytical results showed that delta 14C values in plant samples collected from the highly contaminated areas such as Okuma and Namie were considerably higher than the background values measured in

  7. Algal photosynthetic activity measurement by 14C uptake, (1)

    International Nuclear Information System (INIS)

    There are many sample preparation techniques for 14C-labeled phytoplankton for radioactivity measurement by liquid scintillation counting. A number of sample preparation procedures were tested to identify the ones most suitable for the intended experiments. The following results were obtained: 1. The calculated radioactivity of solubilized samples were about 10% lower than that of combusted samples. This was caused by settling out of algal cells. 2. The agreement between calculated radioactivity of solubilized samples and combusted samples was improved by the addition of Cab-O-Sil. 3. Virtually all of the residual inorganic 14C radioactivity was removed during drying. 4. The loss of 14C radioactivity caused by formaldehyde fixation differed from species to species. Based on these results, the following procedure was selected for use in our experiments: 1. After incubation with 14C, the 14C-labeled phytoplankton samples were immediately filtered and rinsed with filtered seawater under low illumination. 2. The filters were then dried in a vacuum desiccator with sodalime and silica gel. 3. The dried filters were solubilized with ethylene glycol monomethyl ether-toluene fluor which contains PPO, POPOP, and Cab-O-Sil. 4. The activity of solubilized samples was measured using liquid scintillation counting. (author)

  8. Whole-body autoradiographic study on the distribution of pivampicillin-14C labeled at the ampicillin and ester moieties in mice, as compared with those of ampicillin-14C, formaldehyde-14C and pivalic acid-14C

    International Nuclear Information System (INIS)

    The distribution of pivampicillin-14C labeled at the phenylglycyl and the oxymethylene moieties and ampicillin-14C were investigated by whole-body autoradiography after oral administration to mice. The distribution of formaldehyde-14C and pivalic acid-14C was also investigated for comparison. The results revealed that, i) pivampicillin is absorbed from intestine much more rapidly and to a larger extent than ampicillin, ii) the distribution pattern was, however, the same for the two drugs, being mainly restricted to the excretory organs such as the liver, kidney, gall and urinary bladders and intestinal tract, and iii) the oxymethylene moiety, the ester group, showed a completely different distribution pattern, being distributed in the bone marrow, pancreas, intestinal mucosa, spleen and thymus; the pattern being the same as that after administration of formaldehyde-14C. It was therefore suggested that pivampicillin is hydrolyzed in vivo to form ampicillin and formaldehyde before entering into the general circulation and that formaldehyde formed is partly incorporated into the general metabolic pathways in the tissues of a rapid cell division or protein synthesis. Pivalic acid, which is to be liverated simultaneously, was shown to be well absorbed, distributed in the bone, kidney, olfactory bulb, salivary gland and some adipose tissues and finally excreted into the urine mostly as its conjugated forms. (author)

  9. Measuring the 14C content in liquid scintillators

    Science.gov (United States)

    Enqvist, T.; Barabanov, I. R.; Bezrukov, L. B.; Gangapshev, A. M.; Gavrilyuk, Y. M.; Grishina, V. Yu; Gurentsov, V. I.; Hissa, J.; Joutsenvaara, J.; Kazalov, V. V.; Krokhaleva, S.; Kutuniva, J.; Kuusiniemi, P.; Kuzminov, V. V.; Kurlovich, A. S.; Loo, K.; Lubsandorzhiev, B. K.; Lubsandorzhiev, S.; Morgalyuk, V. P.; Novikova, G. Y.; Pshukov, A. M.; Sinev, V. V.; Słupecki, M.; Trzaska, W. H.; Umerov, Sh I.; Veresnikova, A. V.; Virkajärvi, A.; Yanovich, Y. A.; Zavarzina, V. P.

    2016-05-01

    We are going to perform a series of measurements where the 14C/12 C ratio will be measured from several liquid scintillator samples with a dedicated setup. The setup is designed with the aim of measuring ratios smaller than 10-18. Measurements take place in two underground laboratories: in the Baksan Neutrino Observatory, Russia and in the Pyhäsalmi mine, Finland. In Baksan the measurements started in 2015 and in Pyhäsalmi they start in the beginning of 2015. In order to fully understand the operation of the setup and its background contributions a development of simulation packages has also been started. Low-energy neutrino detection with a liquid scintillator requires that the intrinsic 14C content in the liquid is extremely low. In the Borexino CTF detector at Gran Sasso, Italy the 14C/12C ratio of 2 × 10-18 has been achieved being the lowest 14C concentration ever measured. In principle, the older the oil or gas source that the liquid scintillator is derived of and the deeper it situates, the smaller the 14C/12C ratio is supposed to be. This, however, is not generally the case, and the ratio is probably determined by the U and Th content of the local environment.

  10. In vitro synthesis and purification of UDP-[14C] galacturonate

    International Nuclear Information System (INIS)

    Pectins comprise a major component of the cell wall and much research has focused on degradation of pectins during ripening and senescence. However, little research has been conducted on pectin synthesis, partly due to a lack of commercial availability of UDP-[14C]galacturonic acid for use as a substrate in assaying galacturonan synthase. We report on the modification and integration of several procedures to synthesize UDP-[14C] galacturonic acid from commercially available UDP-[14C]glucuronic acid. A microsomal pellet containing UDP-D-glucuronate-4-epimerase was extracted from 5-day-old mung bean hypocotyls (Phaseolus aureus) and radish roots (Raphanus sativus L.) by ultracentrifugation at 30,000 rpm for 50 min. The UDP-[14C]galacturonic acid produced was separated from remaining UDP-[14C]glucuronic acid and other products by electrophoresis in pyridine:acetate:H2O on silica gel. Spots were detected by autoradiography, eluted with 80% ethanol, and purified using anion exchange chromatography

  11. Extension of the HVE 1 MV multi-element AMS system for low background

    International Nuclear Information System (INIS)

    HVE has extended its 1 MV multi-element AMS system to enhance its performance on elements like 10Be and 14C as well as actinides like Pu. The original system is very compact, but had some inherent limitations on e.g. background and the mass resolution of the injector magnet. With the extension, system performance has improved in several aspects: For actinide measurements, the low-energy spectrometer is equipped with a 120 ° magnet featuring a high mass resolution (M/ΔM > 1000) and a high bending power (340 amu at 35 keV), supporting e.g. injection of 244Pu19F5. For 3H AMS, all magnets are equipped with Hall-probe control. The accelerator is equipped with a dual gas stripper system. The high energy spectrometer was extended by a 30 degree magnet removing ions scattering in the high-energy ESA. This has improved the background for 10Be AMS by two orders of magnitude down to the low 10−16. For 14C AMS the magnet allows using charge state 1+ by suppressing scattered 13C to a level also in the low 10−16. The new system has a footprint of 10.4 m × 4.9 m, including a second ion source in the injector and provisions for future implementation of an isobar separator for anions (ISA) for e.g. 36Cl measurements. The first extended system will be delivered to the Aarhus AMS 14C Dating Centre

  12. Extension of the HVE 1 MV multi-element AMS system for low background

    Energy Technology Data Exchange (ETDEWEB)

    Klein, M., E-mail: info@highvolteng.com [High Voltage Engineering Europa B.V., Amersfoort (Netherlands); Heinemeier, J. [AMS " 1" 4C Dating Centre, Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark); Gottdang, A.; Mous, D.J.W. [High Voltage Engineering Europa B.V., Amersfoort (Netherlands); Olsen, J. [AMS " 1" 4C Dating Centre, Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark)

    2014-07-15

    HVE has extended its 1 MV multi-element AMS system to enhance its performance on elements like {sup 10}Be and {sup 14}C as well as actinides like Pu. The original system is very compact, but had some inherent limitations on e.g. background and the mass resolution of the injector magnet. With the extension, system performance has improved in several aspects: For actinide measurements, the low-energy spectrometer is equipped with a 120 ° magnet featuring a high mass resolution (M/ΔM > 1000) and a high bending power (340 amu at 35 keV), supporting e.g. injection of {sup 244}Pu{sup 19}F{sub 5}. For {sup 3}H AMS, all magnets are equipped with Hall-probe control. The accelerator is equipped with a dual gas stripper system. The high energy spectrometer was extended by a 30 degree magnet removing ions scattering in the high-energy ESA. This has improved the background for {sup 10}Be AMS by two orders of magnitude down to the low 10{sup −16}. For {sup 14}C AMS the magnet allows using charge state 1+ by suppressing scattered {sup 13}C to a level also in the low 10{sup −16}. The new system has a footprint of 10.4 m × 4.9 m, including a second ion source in the injector and provisions for future implementation of an isobar separator for anions (ISA) for e.g. {sup 36}Cl measurements. The first extended system will be delivered to the Aarhus AMS {sup 14}C Dating Centre.

  13. Benzene Synthesis for ''14C Measurements and Evaluation of Uncertainty in Mollusk Shells; Sintesis de Benceno para la Determinacion de C''14 y Evaluacion de su Incertidumbre en Conchas de Moluscos

    Energy Technology Data Exchange (ETDEWEB)

    Romero del Hombrebueno, B.; Simon, M. A.; Larena, P.

    2002-07-01

    This work describes the method and instrumentation used by Environmental Isotopes laboratory of the CIEMAT Analytical Chemistry Laboratory (DIAE) for the synthesis of benzene from carbonates of mollusk shells and the liquid scintillation counting of ''14C for radiocarbon dating in these samples. The usefulness of mollusk shells for ''14 C dating are considered. (Author)

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  16. Synthesis of paclitaxel-C3`-{sup 14}C

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.G.; Standridge, R.T.; Swigor, J.E. [Bristol-Myers-Squibb Co., Syracuse, NY (United States). Pharmaceutical Research Inst.

    1995-12-31

    Reductive cleavage of the C13 side chain of paclitaxel (3) followed by regioselective silylation gave 7-triethylsilybaccatin lll (6). Successive reaction of L-threonine methyl ester hydrochloride (7) with tertbutoxydiphenylchlorosilane, benzaldehyde-C7-{sup 14}C and acetoxyacetyl chloride/triethylamine gave a 92:8 ratio (NMR) of azetidinones in 57% yield from 7. Removal of the chiral auxiliary, and 3-O-triethylsilylation and N-benzoylation provided (3R,4S)-cis-1-benzoyl-3-O-(triethylsilyl)-4-phenylazetidin-2-one-C 4-{sup 14}C (18). Coupling of 18 and 6 followed by deprotection gave 1.12 g of paclitaxel-C3`-{sup 14}C having a specific activity of 16.4 mCi/mmol and a radiochemical purity of 96%. (Author).

  17. Transformation of Straw 14C in Ultisol and Vertisol

    Institute of Scientific and Technical Information of China (English)

    WANGZHIMING; HUANGDONGMAI; 等

    1998-01-01

    Laboratory incubation was conducted to investigate transformation of straw 14C in Ultisol and Vertisol under aerobic conditiol for 112 d at 30℃,Dried and ground 14C-labeled rice and majze straws sere mixed with the soils at the rate of 2.5g kg-1 ,Decomposition of the straw C and native soil C both revealed two stages,being faster during the intial day,and slower thereafter,About 37.33%-48.80% of the straw C and 4.22%-6.83% of the native soil C decomposed by the end of the incubation.The kinds of the straws only slightly influenced the rates of their decomposition in soils,however,some retardation was found in Ultisol at the intial decomposition stage due to its lowr pH.Positvie priming effects were observed in the soils spplied with straw ,and the rate of priming effect ranged from 7.23% to 13.80%.Net losses of native soil C were found under such incubation conditions ,except Ultisol with rice straw.Soil biomass of and 14C decreased gradually with incubation time,and seemed to be consistent with the decomposition patterns of straw C and native soil C.The ratio of biomass 12C to biomass 14C ranged from 1.35 to 3.37 .soil biomass C occupied 1.17%-2.32% of the total soil organic C,and the proportion of biomass 14C to the residual 14C varied from 7.3% to 14.3%.

  18. AMS radiocarbon dating at Oxford and its contribution to issues of the extinction of Neanderthals and the spread of Homo sapiens sapiens across Eurasia

    International Nuclear Information System (INIS)

    The Oxford Radiocarbon Accelerator Unit has participated in a number of projects central to the question of the evolutionary fate of the Neanderthals and the spread of our own species across Eurasia. This paper outlines some of the key issues in this field and reports on some dating projects which have refined our knowledge of these momentous events in human history

  19. AMS radiocarbon dating at Oxford and its contribution to issues of the extinction of Neanderthals and the spread of Homo sapiens sapiens across Eurasia

    CERN Document Server

    Pettitt, P B; Hedges, R E M; Hodgins, G W L

    2000-01-01

    The Oxford Radiocarbon Accelerator Unit has participated in a number of projects central to the question of the evolutionary fate of the Neanderthals and the spread of our own species across Eurasia. This paper outlines some of the key issues in this field and reports on some dating projects which have refined our knowledge of these momentous events in human history.

  20. Verification of the dispersion model by airborne carbon 14C

    International Nuclear Information System (INIS)

    This paper provides insight in the verification of the Lagrangean dispersion model for dose calculation in the environment. The verification method was based on the measurement of the airborne carbon 14C concentration which can be slightly increased close to the nuclear power plant. The results proved that this method is sensitive enough and that the sensitivity analysis can be used for model verification or for identification of possible improvements of the used meteorological data. The Lagrangean model is used at Krsko nuclear power plant (NPP) for calculation of dispersion coefficients and dose in the environment. To show compliance with the authorized dose limits it is required to present a realistic calculation of the dose to the public. This is a numerical model designed to calculate air pollution dispersion in the area of 25km x 25km. The model uses on-line local meteorological measurements. The same model was already verified for another location around a coal- fired power plant based on emission and environmental measurements of SO2. Krsko NPP is placed near the Sava River in a semiopened basin surrounded by several hills. The region is characterized by low winds and frequent thermal inversions. This paper presents a verification of the short range dispersion model based on the fact that the airborne carbon 14C concentration can be slightly increased close to the nuclear power plant. Other radioactive effluents are not detectable in the environment and carbon 14C measurements are accurate enough to detect small deviations from natural 14C levels and to compare them with the calculated concentration based on 14C effluents. The most of airborne 14C is released during the refuelling outage. Within the pre-selected period of ten days, increased effluents of 14C in the form of CO2 were sampled from the plant ventilation. The average atmospheric dispersion parameters were calculated for two locations in the environment where CO2 sampling plates were installed

  1. Biliary excretion of intravenous [14C] omeprazole in humans

    International Nuclear Information System (INIS)

    We have studied the biliary excretion of [14C] omeprazole in humans. The study was performed in eight healthy subjects and the technique used was based on multiple marker dilution principles with double-lumen tubes placed in both the stomach and intestine. The results obtained show a 16% biliary excretion of [14C] omeprazole. These data suggest a minimal spillover of omeprazole from the gastric mucosa into the gastric lumen in humans. The results also agree with previous data of the fecal recovery of radiolabeled omeprazole that suggest that the fecal excretion of intravenous omeprazole in humans is entirely accounted for by biliary excretion

  2. Comment on "Radiocarbon Calibration Curve Spanning 0 to 50,000 Years B.P. Based on Paired 230Th/234U/238U and 14C Dates on Pristine Corals" by R.G. Fairbanks, R. A. Mortlock, T.-C. Chiu, L. Cao, A. Kaplan, T. P. Guilderson, T. W. Fairbanks, A. L. Bloom, P

    Energy Technology Data Exchange (ETDEWEB)

    Reimer, P J; Baillie, M L; Bard, E; Beck, J W; Blackwell, P G; Buck, C E; Burr, G S; Edwards, R L; Friedrich, M; Guilderson, T P; Hogg, A G; Hughen, K A; Kromer, B; McCormac, G; Manning, S; Reimer, R W; Southon, J R; Stuiver, M; der Plicht, J v; Weyhenmeyer, C E

    2005-10-02

    Radiocarbon calibration curves are essential for converting radiocarbon dated chronologies to the calendar timescale. Prior to the 1980's numerous differently derived calibration curves based on radiocarbon ages of known age material were in use, resulting in ''apples and oranges'' comparisons between various records (Klein et al., 1982), further complicated by until then unappreciated inter-laboratory variations (International Study Group, 1982). The solution was to produce an internationally-agreed calibration curve based on carefully screened data with updates at 4-6 year intervals (Klein et al., 1982; Stuiver and Reimer, 1986; Stuiver and Reimer, 1993; Stuiver et al., 1998). The IntCal working group has continued this tradition with the active participation of researchers who produced the records that were considered for incorporation into the current, internationally-ratified calibration curves, IntCal04, SHCal04, and Marine04, for Northern Hemisphere terrestrial, Southern Hemisphere terrestrial, and marine samples, respectively (Reimer et al., 2004; Hughen et al., 2004; McCormac et al., 2004). Fairbanks et al. (2005), accompanied by a more technical paper, Chiu et al. (2005), and an introductory comment, Adkins (2005), recently published a ''calibration curve spanning 0-50,000 years''. Fairbanks et al. (2005) and Chiu et al. (2005) have made a significant contribution to the database on which the IntCal04 and Marine04 calibration curves are based. These authors have now taken the further step to derive their own radiocarbon calibration extending to 50,000 cal BP, which they claim is superior to that generated by the IntCal working group. In their papers, these authors are strongly critical of the IntCal calibration efforts for what they claim to be inadequate screening and sample pretreatment methods. While these criticisms may ultimately be helpful in identifying a better set of protocols, we feel that there are

  3. Use of JAEA Mutsu AMS facility at Japan Marine Science Foundation. A history and current simulation

    International Nuclear Information System (INIS)

    AMS measurements on samples for marine environmental studies as well as small number of geological and archaeological samples were made at Japan Marine Science Foundation by using the Tandetron AMS facility of Japan Atomic Energy Agency at Mutsu, Aomori Prefecture for 14C since 2001, and 129I since 2006. In this report, an early historical relationship of this institute to JAEA Mutsu AMS, past applications until 2006 and a few examples of obtained results are described. Approximately seven hundred 14C measurements were carried out for seawater, marine sediment and tree-ring samples as well as geological and archaeological materials. About one hundred 129I measurements were made for seawater samples in 2006. Three glass-made vacuum lines are in operation for seawater DIC, preparation and purification for the general purpose, and graphitization. Dating calculations are made on the total 14C count and individual 13C current measurements following Stuiver and Polach. Two wooden pillars excavated at Sannai Maruyama Jomon site were dated using small parts from them and by wiggle matching methods first based on Pearson's and later being based on a Bayesian method, respectively and more recently by OxCal 4. As an alternative means for a long-term measurement of atmospheric 14C concentrations and as part of marine environmental studies, tree-rings were analyzed using core samples from standing, live, Japanese pine trees. In parallel, 14C concentrations were measured for rings from a partial disk of an old Japanese cedar tree near Aomori City. Both results were in agreement during the period 1990-2000. The latter data during 1945-2000 showed influences of the large-scale atmospheric nuclear weapons tests; small differences being found between the present and literature data in 1970s suggesting need for further study on possible local effects. Iodine-129 with added carrier in sweater was extracted as molecular iodine with hexane after reducing iodate to iodide. Iodine was

  4. Biomonitoring of 14C in the vicinity of NPPs

    Czech Academy of Sciences Publication Activity Database

    Světlík, Ivo; Molnár, M.; Svingor, E.; Rinyu, L.; Futó, I.; Michálek, V.

    Brasov : IRPA, 2007, s. 1-10. [IRPA Regional Congress for Central and Eastern Europe. Brasov (RO), 24.09.2007-28.09.2007] Institutional research plan: CEZ:AV0Z10480505 Keywords : 14C excess * Suess effect * biota monitoring * nuclear power plants Subject RIV: DG - Athmosphere Sciences, Meteorology

  5. Biokinetic studies on 14C-chitosan in rats

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  7. Synthesis of [sup 14]C-radiolabeled ractopamine hydrochloride

    Energy Technology Data Exchange (ETDEWEB)

    Terando, N.H. (DowElanco, Greenfield Labs., Greenfield, IN (United States))

    1992-09-01

    Ractopamine HC1 was uniformly labeled with carbon-14 in one of two phenyl rings as a requirement for animal metabolism studies. The six-step synthesis was completed in a 14% yield. Product instability on silica gel complicated purification, but development of a chromatographic method afforded ractopamine HCl-[sup 14]C with a radiochemical purity of 98.2%. (author).

  8. Synthesis of 14C-radiolabeled ractopamine hydrochloride

    International Nuclear Information System (INIS)

    Ractopamine HC1 was uniformly labeled with carbon-14 in one of two phenyl rings as a requirement for animal metabolism studies. The six-step synthesis was completed in a 14% yield. Product instability on silica gel complicated purification, but development of a chromatographic method afforded ractopamine HCl-14C with a radiochemical purity of 98.2%. (author)

  9. Photosynthetic incorporation of 14C by Stevia rebaudiana

    International Nuclear Information System (INIS)

    The photosynthetic incorporation of 14 by Stevia rebaudiana specimens was investigated. The 14C incorporation, when the isotope was furnished to the plant in form of 14CO2, was rapid. After 24 hours, the radioactivity has been incorporated into a great number of compounds including pigments, terpenes, glucose, cellulose and also stevioside and its derivatives. (M.A.C.)

  10. Fungal bio-degradation of 14C-parathion

    International Nuclear Information System (INIS)

    14'C-parathion (670 Bq) was applied to mineral salt medium (MSM) to examine and evaluate its biodegradation by some fungi. The studied isolates were Alternaria alternate, Fusarium oxysporim and trichoderma viride. The inoculated media were incubated at 30 oC for periods of 2, 4, 6 and 8 days. Ta each interval, mycelia were separated from nutrient solution and extracted for its radioactivity. However, non extractable compounds were liberated by combustion. Quantitative and qualitative analysis were carried out for the radioactive compound in mycelia l extracts and residues as well as the fungal culture filtrate. Balance sheet for total recovered radioactive compounds was concluded 14'C-parathion metabolism was expressed as original compound, polar metabolite, non polar metabolites and non extractable residues and then degradation rate was calculated. araesults indicated that there was continuous penetration for the radioactivity into mycelia tissues and the maximum, accumulation was recorded by Fusarium Oxysporium. The fungi under investigation showed considerable variations regarding their capacity to degrade the radioactive pesticide. Trichoderma viride exhibited the maximum capability to catabolism the the 14C-parathion as it exerted the maximum degradation rate. Fusarium and Alternate alter nata showed less degradation rates for the 14C- pesticide under investigation. (Author)

  11. Extraction of in situ cosmogenic 14C from olivine

    Science.gov (United States)

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

    2010-01-01

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

  12. Reconstructing Ocean Circulation using Coral (triangle)14C Time Series

    Energy Technology Data Exchange (ETDEWEB)

    Kashgarian, M; Guilderson, T P

    2001-02-23

    We utilize monthly {sup 14}C data derived from coral archives in conjunction with ocean circulation models to address two questions: (1) how does the shallow circulation of the tropical Pacific vary on seasonal to decadal time scales and (2) which dynamic processes determine the mean vertical structure of the equatorial Pacific thermocline. Our results directly impact the understanding of global climate events such as the El Nino-Southern Oscillation (ENSO). To study changes in ocean circulation and water mass distribution involved in the genesis and evolution of ENSO and decadal climate variability, it is necessary to have records of climate variables several decades in length. Continuous instrumental records are limited because technology for continuous monitoring of ocean currents (e.g. satellites and moored arrays) has only recently been available, and ships of opportunity archives such as COADS contain large spatial and temporal biases. In addition, temperature and salinity in surface waters are not conservative and thus can not be independently relied upon to trace water masses, reducing the utility of historical observations. Radiocarbon in sea water is a quasi-conservative water mass tracer and is incorporated into coral skeletal material, thus coral {sup 14}C records can be used to reconstruct changes in shallow circulation that would be difficult to characterize using instrumental data. High resolution {Delta}{sup 14}C timeseries such as ours, provide a powerful constraint on the rate of surface ocean mixing and hold great promise to augment one time oceanographic surveys. {Delta}{sup 14}C timeseries such as these, not only provide fundamental information about the shallow circulation of the Pacific, but can also be directly used as a benchmark for the next generation of high resolution ocean models used in prognosticating climate. The measurement of {Delta}{sup 14}C in biological archives such as tree rings and coral growth bands is a direct record of

  13. High-precision accelerator-mass-spectrometer radiocarbon dating of buried tidal-marsh soils - An approach to estimating the frequency and coastal extent of subduction zone earthquakes in Oregon and Washington

    International Nuclear Information System (INIS)

    Accurate and precise radiocarbon dating of buried tidal-marsh soils in estuarine stratigraphic sequences in the Pacific Northwest can help distinguish soils submerged during regional plate-boundary earthquakes from soils submerged during local upper-plate earthquakes or by non-tectonic processes. More precise ages than those resulting from conventional methods of radiocarbon analysis can be obtained by averaging multiple accelerator-mass-spectrometer (AMS) 14C ages of rigorously selected and pretreated plant macrofossils at the abrupt upper contacts of tidal-marsh soils. An initial test of this method in Coos Bay, Oregon, shows that standard deviations on AMS ages can be reduced to ± 25-40 radiocarbon years. But consideration of the total analytical errors in AMS analysis and age differences due to variations in the rate of 14C production in the atmosphere over time indicate that 95% confidence limits on calendar-corrected ages for submergence events range from 50 to 450 years

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-26

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsson, Mikael

    2002-08-01

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

  17. Decay of 226Ra by 14C emission

    International Nuclear Information System (INIS)

    Since the pioneering experiment by Rose and Jones in 1984 demonstrating 14C decay of 223Ra, spontaneous emission of clusters heavier than α particles but lighter than fission products could be found in several cases to be a rare decay mode of heavy nuclei. This new kind of radioactivity has branching ratios relative to α decay well below 10-9. For energetical reasons the emitted fragments are even-even and the daughter nucleus lies close to the doubly magic 208Pb. Polycarbonate track-recording foils which are sensitive to energetic carbon nuclei but not to α particles are very well suited detectors for the study of 14C emission radioactivity. The tracks are made visible under a microscope by etching techniques. Observation of spontaneous emission of 14C from 226Ra claimed by Hourani et al. and Barwick et al. has been confirmed. Since thick sources of 226Ra were used in these experiments the experimental definitions of decay energy and mass were not very accurate. The experiment described in the thesis measured for the first time charge and energy of the emitted fragments by using thin 226Ra sources and polycarbonate track-recording films. The decay mode could thus be identified unambiguously. The track detector was calibrated with tandem-accelerated 14C and 16O ions and tested by observing the now well established 14C emission from 223Ra; for this decay mode a branching ratio of (5,0 ± 1,0).10-10 relative to α decay was found in agreement with values from the literature. In the case of 226Ra the result for 14C/α ratio is (2,3 ± 1,2).10-11. The order of magnitude of the branching ratios can be reproduced by theoretical models. Estimates of partial half-lifes of Ra and other heavy isotopes for rare decay modes are discussed in the theoretical section of the thesis. 100 refs., 3 tabs., 30 figs. (Author)

  18. A Column Experiment To Determine Black Shale Degradation And Colonization By Means of δ13C and 14C Analysis Of Phospholipid Fatty Acids And DNA Extraction

    Science.gov (United States)

    Seifert, A.; Gleixner, G.

    2008-12-01

    We investigated the degradation of black shale organic matter by microbial communities. We inoculated two columns respectively, with the fungi Schizophyllum commune, the gram-positive bacterium Pseudomonas putida and the gram-negative bacteria Streptomyces griseus and Streptomyces chartreusis. These microorganisms are known to degrade a wide variety of organic macromolecules. Additionally, we had two sets of control columns. To one set the same nutrient solution was added as to the inoculated columns and to the other set only sterile deionised water was supplied. All columns contained 1.5 kg of freshly crushed not autoclaved black shale material with a particle size of 0.63-2 mm. The columns were incubated at 28° C and 60% humidity in the dark. The aim was to investigate, which microorganisms live on black shales and if these microorganisms are able to degrade ancient organic matter. We used compound specific stable isotope measurement techniques and compound specific 14C-dating methods. After 183 days PLFAs were extracted from the columns to investigate the microbial community, furthermore we extracted on one hand total-DNA of column material and on the other hand DNA from pure cultures isolates which grew on Kinks-agar B, Starch-casein-nitrate-agar (SCN) and on complete-yeast-medium-agar (CYM). According to the PLFA analysis bacteria dominated in the columns, whereas in pure cultures more fungi were isolated. A principal component analysis revealed differences between the columns in accordance with the inoculation, but it seems that the inoculated microorganisms were replaced by the natural population. For AMS measurements palmitic acid (C 16:0) was re-isolated from total-PLFA-extract with a preparative fraction collector (PFC). Preliminary results of the study revealed that microorganisms are able to degrade black shale material and that PLFA analysis are useful methods to be combined with analysis of stable isotope and 14C measurements to study microbial

  19. New radiocarbon dates for Milu (Elaphurus davidianus) sub-fossils from southeast China

    Energy Technology Data Exchange (ETDEWEB)

    Ding, X.F. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Shen, C.D., E-mail: cdshen@gig.ac.cn [State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou (China); Ding, P.; Yi, W.X. [State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou (China); Fu, D.P.; Liu, K.X. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2013-01-15

    Milu (Elaphurus davidianus, Pere David's deer) is one of the few species of large mammals that became extinct in the wild, but survived domestically. A good understanding of expansion and habitat is required if the reintroduction of Milu into the wild is to be implemented. Among the widely reported findings of Milu sub-fossils, only a small fraction have been dated. Here we report new AMS radiocarbon dates on Milu sub-fossil samples unearthed from two sites at Qingdun, Jiangsu and Fujiashan, Zhejiang in southeast China. These AMS {sup 14}C ages of Milu sub-fossils provide new evidence for the presence of Milu expansion in the lower reaches of the Yangtze River during the Holocene Optimum interval from 5000 yr BC to 3000 yr BC. These new ages also have important implications for the reconstruction of the paleoclimate and paleogeography during the Neolithic Period in southeast China.

  20. [14C] acetylation of a glycosaminoglycan sulphate: Sulodexide

    International Nuclear Information System (INIS)

    The synthesis of [14C] labelled Sulodexide is reported. Sulodexide is a sulphated polysaccharide of the class of glycosaminoglycan, containing a heparin-like fraction (70%), dermatan sulphate (20%) and other minor fractions. The heparin-like fraction, suitably isolated from other components, was partially and selectively N-desulphated, thus making few percent unit -NH2 groups available for the labelling with [14C]-acetic anhydride (specific activity 0.15 μCi/mg). Due to the small extent of modification, the sulphate to carboxylate group ratio remained practically unchanged on the heparin-like fraction. Sulodexide was reconstituted adding to the labelled fraction the suitable amount of the other components; the chemical and biological properties of the final labelled Sulodexide were indistinguishable from those of the starting material. (author)

  1. Fate of 14C-monocrotophos in lactating goats

    International Nuclear Information System (INIS)

    14C-monocrotophos was fed daily to two groups of lactating goats for five days at 5 and 10 mg per goat per day. The radioactivity in urine and faeces accounted for 50% and 7%, respectively, 24 hours after the first dose. About 25% of the radiocarbon was found in various organs. About 1-2% of the administered radiocarbon was secreted in milk. It was concluded that monocrotophos was rapidly eliminated through urine and faeces of teddy goats. 14C-residues in milk and urine were tentatively identified as monocrotophos, dimethylphosphate and N-desmethyl monocrotophos. The erythrocyte cholinesterase activity was reduced to 50% 24 hours after treatment, but no toxic symptoms were observed. (author)

  2. Plasmid DNA labelled with 14C or 3H

    International Nuclear Information System (INIS)

    Plasmid DNA labelled with 14C or 3H in thymine was isolated from the thymine-dependent strain of Escherichia coli 15 SPT bacteria. The specific activity of the plasmid DNA preparations lay in the range from 0.5 to 20 MBq/mg, their relative molecular weight was 1.7 x 106 dalton. Molecular weight, preparation purity, and the degree of damage of the plasmid DNA molecules were examined by UV absorption spectroscopy, by gel electrophoresis, and by electron micrography. The quality of the [thymine-2-14C] plasmid DNA was verified in a diagnostic test for the determination of the anti-dsDNA bonding activity in human serum. (author). 1 tab., 5 figs., 30 refs

  3. 41Ca, 14C and 10Be concentrations in coral sand from the Bikini atoll.

    Science.gov (United States)

    Lachner, Johannes; Christl, Marcus; Alfimov, Vasily; Hajdas, Irka; Kubik, Peter W; Schulze-König, Tim; Wacker, Lukas; Synal, Hans-Arno

    2014-03-01

    Activation measurements of materials exposed to nuclear bomb explosions are widely used to reconstruct the neutron flux for retrospective dosimetry. In this study the applicability of coral CaCO3 as a biogenic neutron fluence dosimeter is tested. The long-lived radioisotopes (41)Ca, (14)C and (10)Be, which had been produced in nuclear bomb explosions, are measured in several coral sand samples from the Bikini atoll at the 600 kV and 200 kV AMS facilities of ETH Zurich. Elevated concentrations of all studied isotopes are found in a sample from the crater that was initially formed by the high-yield nuclear explosion Castle Bravo in 1954 and that had been used as site for several tests afterward. The observed (14)C concentration is considered too large to originate from neutron irradiation of CaCO3 alone. The relatively low concentration of (10)Be found in the crater sample indicates that production of (10)Be during nuclear bomb testing is generally minor. A simple neutron fluence reconstruction is performed on basis of the (41)Ca/(40)Ca ratio. PMID:24378732

  4. TMEM14C is required for erythroid mitochondrial heme metabolism

    OpenAIRE

    Yien, Yvette Yee; Robledo, Raymond F.; Schultz, Iman J.; Takahashi-Makise, Naoko; Gwynn, Babette; Bauer, Daniel Evan; Dass, Abhishek; Yi, Gloria; Li, Liangtao; Hildick-Smith, Gordon J.; Cooney, Jeffrey D.; Pierce, Eric Adam; Mohler, Kyla; Dailey, Tamara A.; Miyata, Non

    2014-01-01

    The transport and intracellular trafficking of heme biosynthesis intermediates are crucial for hemoglobin production, which is a critical process in developing red cells. Here, we profiled gene expression in terminally differentiating murine fetal liver-derived erythroid cells to identify regulators of heme metabolism. We determined that TMEM14C, an inner mitochondrial membrane protein that is enriched in vertebrate hematopoietic tissues, is essential for erythropoiesis and heme synthesis in ...

  5. Residues of 14C-paclobutrazol in mangoes

    International Nuclear Information System (INIS)

    Paclobutrazol (PBZ) is a growth regulator used in agricultural systems whose purpose is the control of vegetative growth, stimulating the reproductive capacity of plants. This growth regulator remains active in soil for a long time and its half-life varies with the type of soil and climatic conditions, can severely affect the development of crops. This work aimed to study the residues / metabolites of 14C-PBZ in mango pulp Tommy Atkins. The tests were performed with mangoes grown in pots stainless steel and application of 14C-PBZ was performed by the soil projection of the crown, and the mangoes tested in two periods, one year and two years after application. To evaluate the levels of residues of 14C-PBZ was realize the burning of 200 mg of pulp on biological oxidized and detached 14CO2 was detected by liquid scintillation spectrophotometer. The results were 1.65 % of residue of PBZ on fruit collected after two years of application and 4.30 % of residue of PBZ collected on fruit after a year of application and also can see that the product remained in the soil for more than one year, is translocated to the plant and reach the edible part, the pulp fruit. The identification of residual 14C- PBZ/metabolites by thin-layer chromatography did not reveal any pattern of PBZ / metabolites due to the low activity detected in the samples. Therefore, another procedure was performed for extraction and then analyzed by high performance liquid chromatography (HPLC) for detection of metabolites in the PBZ of mango pulp. (author)

  6. Spectrophotometric determination of sugars labelled with 14C

    International Nuclear Information System (INIS)

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

  7. A simplified In Situ cosmogenic 14C extraction system

    Science.gov (United States)

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

    2010-01-01

    We describe the design, construction, and testing of a new, simplified in situ radiocarbon extraction system at the University of Arizona. Blank levels for the new system are low ((234 ?? 11) ?? 103 atoms (1 ??; n = 7)) and stable. The precision of a given measurement depends on the concentration of 14C, but is typically extraction system at Arizona, and lends itself to future automation. ?? 2010 by the Arizona Board of Regents on behalf of the University of Arizona.

  8. Biodegradation of 14 C-atrazine under outdoor conditions

    International Nuclear Information System (INIS)

    Uniformly 14 C-ring labeled atrazine (5 L/ha) was applied to a Typical Hapludox Brazilian Soil sample which was incubated under outdoor conditions. Sample of 200 g (dry weight base) of fresh soil were distributed in Erlenmeyer flasks and the moisture was adjusted for 2/3 rds of the soil field capacity. The flasks were then buried in the Lysimeter Station when they were incubated. The experiment started jointly with a corn planting. The 14 C O2 was analyzed every 15 day, during a period of 150 days. The desorbed, extracted and bound residues were analyzed. The extracted soil was fractionated and the residues in the humin, fulvic and humic acids were determined. At the end of the incubation period (150 days), the 14 CO2 evolved reached up to 36% of the total applied activity, the bound residues were detected in about the same (34%) during the inoculation period, and were distributed in the fractions of fulvic acids (29,91%), humic acids (6,83%) and humin (63,26%). The metabolites formed in the desorbed residues and in the extracted residues were determined using thin layer chromatography with 14 C-detector. After 150 days incubation, desorbed soil residues were identified as atrazine (52,72%), hydroxiatrazine (44%) and desisopropilatrazine (3,28%). The extractable residues contained atrazine (79,29%), hydroxiatrazine (16,22%), desisopropilatrazine (2,25%) and desetylatrazine (2,24%). (author)

  9. Amount and identity of (/sup 14/C) residues in bluegills (Lepomis macrochirus) exposed to (/sup 14/C)triclopyr

    Energy Technology Data Exchange (ETDEWEB)

    Lickly, T.D.; Murphy, P.G.

    1987-01-01

    The level and identity of (/sup 14/C) residues in bluegills (Lepomis macrochirus) exposed to 2.5 mg/L (/sup 14/C) triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) have been determined. The highest level of radioactivity observed in the flesh of a fish at any time point (0.13 mg/kg, calculated as equivalent mg triclopyr/kg fish) was less than 5% of the fish exposure level of 2.5 mg/L, while the maximum level in the remainder (head, skin, and viscera) was about 95% (2.33 mg/kg) of the fish exposure level, indicating no concentrating effect. The principal components observed in the fish tissues were triclopyr, 3,5,6-trichloro-2-pyridinol, 2-methoxy-3,5,6-trichloropyridine and a conjugate. These components accounted for greater than 75% of all the residues observed.

  10. Amount and identity of [14C] residues in bluegills (Lepomis macrochirus) exposed to [14C]triclopyr

    International Nuclear Information System (INIS)

    The level and identity of [14C] residues in bluegills (Lepomis macrochirus) exposed to 2.5 mg/L [14C] triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) have been determined. The highest level of radioactivity observed in the flesh of a fish at any time point (0.13 mg/kg, calculated as equivalent mg triclopyr/kg fish) was less than 5% of the fish exposure level of 2.5 mg/L, while the maximum level in the remainder (head, skin, and viscera) was about 95% (2.33 mg/kg) of the fish exposure level, indicating no concentrating effect. The principal components observed in the fish tissues were triclopyr, 3,5,6-trichloro-2-pyridinol, 2-methoxy-3,5,6-trichloropyridine and a conjugate. These components accounted for greater than 75% of all the residues observed

  11. Methods for treating and conditioning of 14C containing health care waste

    International Nuclear Information System (INIS)

    Health care radioactive waste was previously accepted at Necsa and disposed of on this site in near-surface trenches. This practice was terminated by the regulator during 1997 and since then waste drums have been stored and have now become a Necsa liability. These waste drums containing unknown quantities of 14C. About 2500 drums have been accumulated over the years at the Necsa site. The 14C and 3H contents could not be determined with non-destructive assay methods. A study to minimize the further accumulation of 14C containing health care waste was undertaken and some new regulations implemented to prevent further increase of the liability.The bio-hazardous nature of the waste proved to be the main complication in the development of appropriate characterization and conditioning methods. Possible methods to sterilize the waste as a first step were consequently investigated, and this regards two interesting options received attention. The first was the so-called Stericycle ETD process, during which the waste is shredded in an enclosed environment and then sterilized by means of a technique known as Electro Thermal De-activation, and the second was sterilization with Gamma rays. The latter method had the advantage that shredding and repacking were not required.Once the waste was sterilized the waste could be characterized. The most practical method to do this was to compact the drum in a supercompactor and to analyze the liquid released from the drum during compaction in a laboratory.Reasonably accurate estimates of the 14C contents of the waste packages were obtained in this way and at the same time the waste volume to be disposed of was reduced by at least a factor of four. The option to dispose of the waste without doing any quantification of the 14C was also investigated. This option does not require the waste drums to be opened and therefore no sterilization is required. Characterization is in this case limited to assaying the drums for nuclides that can be

  12. AMS in combustion and tribology research

    International Nuclear Information System (INIS)

    An obvious, but previously untested, application of accelerator mass spectrometry is in the use of 14C as a tag to trace the erosion of combustion of carbon containing materials. The attractiveness of 14C as a site-specific, non-labile tag has been pointed out previously as part of the development of AMS for biomedical applications. Developments in sample handling protocols and in ion source performances have made it possible to work easily over five to seven orders of magnitude in concentration of isotopic labile (105 Modern to 10-2 Modern). The authors show that organics labeled with 14C can be added to fossil materials (naturally depleted in 14C) at no regulatory penalty or radiation hazard and usefully used to measure combustion of specific fractions of fuel or to trace the erosion of graphitic materials into lubricant sumps

  13. First operation of the Bern AMS MICADAS

    International Nuclear Information System (INIS)

    The University of Bern has a long history of experience in precise 14C measurements based on the conventional counting laboratory founded more than 50 years ago. Due to the demanding preparation and measurement procedures, the throughput and required carbon mass of this technique both are the limiting factors. Therefore, the University of Bern decided to update the facility aiming at a new 14C laboratory equipped with an accelerator mass spectrometer (AMS) MICADAS. The focus of this laboratory is twofold. On the one hand, the access to routine 14C analysis for climate research and other disciplines will be improved on site. On the other hand, new hyphenated analytical systems shall be developed for online separation and 14C detection of specific fractions or individual compounds. The MICADAS became operational in November 2012. In this work, instruments, laboratory equipment, measures of quality assurance and first results are presented.

  14. ESR dating at Mezmaiskaya Cave, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, A.R. [Department of Chemistry, Williams College, Williamstown, MA, 01267 (United States)]. E-mail: anne.r.skinner@williams.edu; Blackwell, B.A.B. [Department of Chemistry, Williams College, Williamstown, MA, 01267 (United States); Martin, Sara [Department of Chemistry, Williams College, Williamstown, MA, 01267 (United States); Ortega, A. [RFK Science Research Institute, Flushing, NY, 11366 (United States); Blickstein, J.I.B. [RFK Science Research Institute, Flushing, NY, 11366 (United States); Golovanova, L.V. [Laboratory of Prehistory, St. Petersburg (Russian Federation); Doronichev, V.B. [Laboratory of Prehistory, St. Petersburg (Russian Federation)

    2005-02-01

    Mezmaiskaya Cave has yielded more than 10,000 artifacts, thousands of very well preserved faunal remains, and hominin remains, found in seven Middle Paleolithic (Mousterian) and three Upper Paleolithic levels. A complete Neanderthal infant skeleton was preserved in anatomical juxtaposition lying on a large limestone block, overlain by the earliest Mousterian layer, Layer 3. Twenty-four skull fragments from a 1-2 year-old Neanderthal infant, showing post-mortem deformation, occurred in a pit originating in the Mousterian Layer 2 and penetrating into underlying layers 2A and 2B(1). Bone from Layer 2A was dated by AMS {sup 14}C at 35.8-36.3{+-}0.5 kyr BP. Direct dating of Neanderthal bone from Layer 3 gave an age of 29 kyr, but that is now considered to be due to contamination by modern carbon. Fourteen large mammal teeth from Layers 2 through 3 have been dated by standard electron spin resonance (ESR). Low U concentrations in both the enamel and dentine ensure that ESR ages do not depend significantly on the U uptake model, but do depend strongly on the sedimentary dose rates. Assuming a sedimentary water concentration equal to 20 wt%, ESR ages for the Mousterian layers range from 36.2 to 73.0{+-}5.0 ka.

  15. Radiocarbon dating of silica sinter deposits in shallow drill cores from the Upper Geyser Basin, Yellowstone National Park

    Science.gov (United States)

    Lowenstern, Jacob B.; Hurwitz, Shaul; McGeehin, John P.

    2016-01-01

    To explore the timing of hydrothermal activity at the Upper Geyser Basin (UGB) in Yellowstone National Park, we obtained seven new accelerator mass spectrometry (AMS) radiocarbon 14C ages of carbonaceous material trapped within siliceous sinter. Five samples came from depths of 15-152 cm within the Y-1 well, and two samples were from well Y-7 (depths of 24 cm and 122 cm). These two wells, at Black Sand and Biscuit Basins, respectively, were drilled in 1967 as part of a scientific drilling program by the U.S. Geological Survey (White et al., 1975). Even with samples as small as 15 g, we obtained sufficient carbonaceous material (a mixture of thermophilic mats, pollen, and charcoal) for the 14C analyses. Apparent time of deposition ranged from 3775 ± 25 and 2910 ± 30 14C years BP at the top of the cores to about 8000 years BP at the bottom. The dates are consistent with variable rates of sinter formation at individual sites within the UGB over the Holocene. On a basin-wide scale, though, these and other existing 14C dates hint that hydrothermal activity at the UGB may have been continuous throughout the Holocene.

  16. 'Isotope language' of the Alpine Iceman investigated with AMS and MS

    International Nuclear Information System (INIS)

    This paper reviews the use of stable and radioactive isotopes to elucidate an extraordinary archaeological find, the Alpine Iceman 'Oetzi'. In 1991 the body of this man was accidentally discovered in an ice-filled depression at a high-altitude mountain pass (Tisenjoch, 3210 m) of the Oetztal Alps. This location at the Austrian-Italian border apparently formed an ancient transition across the Alps from South to North. 14C dating of the body with accelerator mass spectrometry (AMS) revealed that the Iceman had lived some 5200 years ago, within the time period from 3370 to 3100 years BC (Before Christ). A variety of other materials from the discovery site were also dated with 14C AMS suggesting a use of the mountain pass at other time periods, and varying climatic conditions. Ongoing investigations with thermal ionization (TIMS), inductively-coupled plasma (ICP-MS) and gas mass spectrometry include isotope ratios of 18O/16O (δ18O), 87Sr/86Sr and 206Pb/204Pb, in order to reveal the Iceman's origin and migrational behavior. Analyzed samples include tooth enamel, bones and contents of his intestine, which all represent different ontogenetic (developmental) stages. The isotopic composition of the Iceman is compared to both soils from archaeological sites and local waters. Taken together, the results point towards an origin of the Iceman in the Southeast of the finding site, consistent with archaeological and paleobotanical data

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

    International Nuclear Information System (INIS)

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

  18. Synthesis of 2-dichloromethyl-2-methyl[2-14C]-1,3-dioxolane

    International Nuclear Information System (INIS)

    The labelled compound was prepared by chlorination of [2-14C]acetone obtained from the barium salt of [1-14C]acetic acid by pyrolysis. The reaction product 1,1-dichloro[2-14C]acetone was converted to 2-dichloromethyl-2-methyl[2-14C]-1,3-dioxolane by condensation with ethylene glycol in the presence of thionyl chloride. Radiochemical yield: 62% based on [1-14C]acetic acid. (author) 7 refs

  19. Method for evaluating the potential of 14C labeled plant polyphenols to cross the blood-brain barrier using accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Bioactive compounds in botanicals may be beneficial in preventing age-related neurodegenerative diseases, but for many compounds conventional methods may be inadequate to detect if these compounds cross the blood-brain barrier or to track the pharmacokinetics in the brain. By combining a number of unique technologies it has been possible to utilize the power of AMS to study the pharmacokinetics of bioactive compounds in the brain at very low concentrations. 14C labeled compounds can be biosynthesized by plant cell suspension cultures co-incubated with radioisotopically-labeled sucrose and isolated and separated into a series of bioactive fractions. To study the pharmacokinetics and tissue distribution of 14C labeled plant polyphenols, rats were implanted with jugular catheters, subcutaneous ultrafiltration probes and brain microdialysis probes. Labeled fractions were dosed orally. Interstitial fluid (ISF) and brain microdialysate samples were taken in tandem with blood samples. It was often possible to determine 14C in blood and ISF with a β-counter. However, brain microdialysate samples 14C levels on the order of 107 atoms/sample required AMS technology. The Brain MicrodialysateAUC/SerumAUC ranged from .021- to .029, with the higher values for the glycoside fractions. By using AMS in combination with traditional methods, it is possible to study uptake by blood, distribution to ISF and determine the amount of a dose which can reach the brain and follow the pharmacokinetics in the brain.

  20. Method for evaluating the potential of {sup 14}C labeled plant polyphenols to cross the blood-brain barrier using accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Janle, Elsa M., E-mail: janle@purdue.ed [Purdue University, Department of Foods and Nutrition, 700 West State Street, West Lafayette, IN 47907-0259 (United States); Lila, Mary Ann [University of Illinois, Department of Natural Resources and Environmental Sciences Urbana IL (United States); Grannan, Michael; Wood, Lauren; Higgins, Aine [Purdue University, Department of Foods and Nutrition, 700 West State Street, West Lafayette, IN 47907-0259 (United States); Yousef, Gad G.; Rogers, Randy B. [University of Illinois, Department of Natural Resources and Environmental Sciences Urbana IL (United States); Kim, Helen [University of Alabama at Birmingham, Department of Pharmacology, Birmingham AB (United States); Jackson, George S. [Purdue University, Department of Physics, West Lafayette, IN (United States); Weaver, Connie M. [Purdue University, Department of Foods and Nutrition, 700 West State Street, West Lafayette, IN 47907-0259 (United States)

    2010-04-15

    Bioactive compounds in botanicals may be beneficial in preventing age-related neurodegenerative diseases, but for many compounds conventional methods may be inadequate to detect if these compounds cross the blood-brain barrier or to track the pharmacokinetics in the brain. By combining a number of unique technologies it has been possible to utilize the power of AMS to study the pharmacokinetics of bioactive compounds in the brain at very low concentrations. {sup 14}C labeled compounds can be biosynthesized by plant cell suspension cultures co-incubated with radioisotopically-labeled sucrose and isolated and separated into a series of bioactive fractions. To study the pharmacokinetics and tissue distribution of {sup 14}C labeled plant polyphenols, rats were implanted with jugular catheters, subcutaneous ultrafiltration probes and brain microdialysis probes. Labeled fractions were dosed orally. Interstitial fluid (ISF) and brain microdialysate samples were taken in tandem with blood samples. It was often possible to determine {sup 14}C in blood and ISF with a beta-counter. However, brain microdialysate samples {sup 14}C levels on the order of 10{sup 7} atoms/sample required AMS technology. The Brain Microdialysate{sub AUC}/Serum{sub AUC} ranged from .021- to .029, with the higher values for the glycoside fractions. By using AMS in combination with traditional methods, it is possible to study uptake by blood, distribution to ISF and determine the amount of a dose which can reach the brain and follow the pharmacokinetics in the brain.

  1. 14C-lindane residues in palm processing

    International Nuclear Information System (INIS)

    A study was undertaken to identify the residue level in palm fruits and its products by spiking the fruits at 5 ppm with 14C-[UL]-lindane and following up on the residue during simulated commercial processes. The study concluded that steam distillation (deodorization) is an effective process in removing lindane residues. Under experimental conditions, commercial processes removed some 74% of insecticide residues from crude palm oil. Based on the oil content (up to 50%) of the pulp the residue concentration in the refined oil may exceed 2.5% mg/kg. The result suggest that the refined oil may retain one quarter of lindane received by the fruit. 1 tab

  2. 14C-coumaphos residues in Egyptian lactating goats

    International Nuclear Information System (INIS)

    14C-coumaphos was applied dermally to two lactating goats, with 2 weeks interval. One goat was sacrificed 24 hours after the second application, and the second animal after a withdrawal period of two weeks. The results showed that coumaphos has a slow penetration rate when dermally applied to lactating goats. Milk residues were 0.20-0.25 ppm following appication, declining gradually to 0.03-0.06 ppm after 2 weeks. The liver and kidney were found to contain considerable amounts of coumaphos residues in comparison with other organs and milk after the withdrawal period. (author)

  3. Comparison of 14C and U-Th ages of two Holocene phreatic overgrowths on speleothems from Mallorca (Western Mediterranean: Environmental implications

    Directory of Open Access Journals (Sweden)

    Tuccimei Paola

    2011-01-01

    Full Text Available This investigation reports on the comparison between ICP-MS U-Th and AMS 14C ages of Phreatic Overgrowths on Speleothems (POS from two different caves on the island of Mallorca (Spain. These speleothem encrustations form at the water table of coastal caves in a low-amplitude tide-controlled microenvironment and are used to reconstruct past sea level changes. The aim of this study is to evaluate if this particular type of speleothem is datable using 14C method and to investigate possible problems connected with the incorporation of dead carbon inherited from the dissolution of 14C-free limestone. The results show that 14C ages are strongly site dependent and appear related to local residence time of water infiltration through the soil and epikarst. When short transit time and limited interaction with soil and bedrock, as in Cova de Cala Varques A, the so-called “reservoir” effect is negligible and 14C and U-Th ages corresponds within the error range. When the residence time is longer, as in Cova des Pas de Vallgornera, 14C ages are steadily 2,300-2,400 years older than the U-Th data, as shown by the mean value (25% of estimated percent dead carbon proportions and by higher and better correlated contents of major and trace elements in the vadose support of this speleothem encrustation. The potential use of this multi-method approach to paleoenvironmental studies is also suggested.

  4. Longevity and growth of Acacia tortilis; insights from 14C content and anatomy of wood

    Directory of Open Access Journals (Sweden)

    Krzywinski Knut

    2007-06-01

    Full Text Available Abstract Background Acacia tortilis is a keystone species across arid ecosystems in Africa and the Middle East. Yet, its life-history, longevity and growth are poorly known, and consequently ongoing changes in tree populations cannot be managed in an appropriate manner. In other arid areas parenchymatic bands marking growth zones in the wood have made dendrochronological studies possible. The possibilities for using pre- and post-bomb 14C content in wood samples along with the presence of narrow marginal parenchymatic bands in the wood is therefore tested to gain further insight into the age, growth and growth conditions of A. tortilis in the hyper-arid Eastern Desert of Egypt. Results Based on age scenarios and the Gompertz growth equation, the age of trees studied seems to be from 200 up to 650 years. Annual radial growth estimated from calibrated dates based on the post-bomb 14C content of samples is up to 2.4 mm, but varies both spatially and temporally. Parenchymatic bands are not formed regularly. The correlation in band pattern among trees is poor, both among and within sites. Conclusion The post-bomb 14C content of A. tortilis wood gives valuable information on tree growth and is required to assess the age scenario approach applied here. This approach indicates high longevities and slow growth of trees. Special management measures should therefore be taken at sites where the trend in tree population size is negative. The possibilities for dendrochronological studies based on A. tortilis from the Eastern Desert are poor. However, marginal parenchymatic bands can give insight into fine scale variation in growth conditions and the past management of trees.

  5. Fate of 14C-deltamethrin in lactating dairy cows

    International Nuclear Information System (INIS)

    Fate and residues of radiocarbon (14C) labelled (gem-dimethyl or benzyl) deltamethrin were determined in lactating cows after oral administration for three consecutive days and slaughtering the animals 24 hr after the last dose. Orally administered deltamethrin (10 mg/kg of body weight) appeared to be poorly absorbed, but the insecticide which was absorbed was extensively metabolized and excreted in the bile and urine with very little accumulation in major edible tissues. Approximately 36-43% of the total administered radiocarbon was eliminated in feces mostly as deltamethrin within 24 hr after the last dose. Only 4-6% of the administered 14C was eliminated in urine; and 0.42-1.62% was secreted in the milk. Radiocarbon secreted into milk was higher for the gem-dimethyl portion (0.69 μg/g) than from the benzyl moiety (0.36 μg/g); deltamethrin was the major product in milk (0.1-0.14 μg/g). Radiocarbon residues in tissues were low (<0.1 μg/g), except liver and kidney (1.28-3.19 μg/g), abdominal and subcutaneous fats (0.28-0.62 μg/g). (author)

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

    International Nuclear Information System (INIS)

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

  7. Airy structure in $^{16}$O+$^{14}$C nuclear rainbow scattering

    CERN Document Server

    Ohkubo, S

    2015-01-01

    The Airy structure in $^{16}$O+$^{14}$C rainbow scattering is studied with an extended double folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic realistic wave functions for $^{16}$O using a density-dependent nucleon-nucleon force. The experimental angular distributions at $E_L$=132, 281 and 382.2 MeV are well reproduced by the calculations. By studying the energy evolution of the Airy structure, the Airy minimum at around $\\theta$=76$^\\circ$ in the angular distribution at $E_L$=132 MeV is assigned as the second order Airy minimum $A2$ in contrast to the recent literature which assigns it as the third order $A3$. The Airy minima in the 90$^\\circ$ excitation function is investigated in comparison with well-known $^{16}$O+$^{16}$O and $^{12}$C+$^{12}$C systems. Evolution of the Airy structure into the molecular resonances with the $^{16}$O+$^{14}$C cluster structure in the low energy region around $E_{c.m.}$=30 MeV is discussed. It is predicted ...

  8. 14C-glycocholate breath test and pathological digestive transit

    International Nuclear Information System (INIS)

    14C-glycine glycocholate breath test is elegant, atraumatic and detects bacterial overgrowth in the proximal portion of small intestine. In such cases an early increase of specific radioactivity of CO2 occurs in expired air. Ileal bile salts malabsorption can also induce such an increase in principle later. However, a modification of transit (acceleration or paresis) can shift the time of appearance of the physiological 14CO2 peak due to colonic deconjugation of the labelled tracer, leading to a diagnostic error. Microbial overgrowth, gastroparesis, accelerated intestinal transit or malabsorption can complicate diabetes mellitus, especially in the case of diabetic neuropathy. Several of these disorder can coexist. It is possible to detect and quantify all these abnormalities in a single examination by the simultaneous use of labelled glycocholate and sup(99m)Tc DTPA. Oral administration of this mixture allows the measurement of gastric emptying half-time and the scintigraphic visualisation of labelled meal progression. Thus, the association of 14C-glycocholate breath-test and sup(99m)Tc DTPA digestive transit insures a correct interpretation in case of associated abnormalities

  9. Cholestyramine-enhanced fecal elimination of carbon-14 in rats after administration of ammonium (/sup 14/C)perfluorooctanoate or potassium (/sup 14/C)perfluorooctanesulfonate

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.D.; Gibson, S.J.; Ober, R.E.

    1984-12-01

    After a single intravenous dose of ammonium (/sup 14/C)perfluorooctanoate (( /sup 14/C)PFO, 13.3 mg/kg) or of potassium (/sup 14/C)perfluorooctanesulfonate (( /sup 14/C)PFOS, 3.4 mg/kg) to rats, cholestyramine fed daily as a 4% mixture in feed was shown to increase the total carbon-14 eliminated via feces and to decrease liver concentration of carbon-14. Rats were fed cholestyramine in feed for 14 days after administration of (/sup 14/C)PFO and for 21 days after administration of (/sup 14/C)PFOS. Control rats were administered radiolabeled fluorochemical but were not treated with cholestyramine. Cholestyramine treatment increased mean cumulative carbon-14 elimination in feces by 9.8-fold for rats administered (/sup 14/C)PFO and by 9.5-fold for rats administered (/sup 14/C)PFOS. After (/sup 14/C)PFO, a mean of 4% of the dose of carbon-14 was in liver of cholestyramine-treated rats at 14 days versus 7.6% in control rats; after (/sup 14/C)PFOS, 11.3% of the dose was in liver at 21 days versus 40.3% in control rats. After administration of either radiolabeled compound, plasma and red blood cell carbon-14 concentrations, which were relatively lower than liver concentrations, were also significantly reduced by cholestyramine treatment.

  10. Cholestyramine-enhanced fecal elimination of carbon-14 in rats after administration of ammonium [14C]perfluorooctanoate or potassium [14C]perfluorooctanesulfonate

    International Nuclear Information System (INIS)

    After a single intravenous dose of ammonium [14C]perfluorooctanoate [( 14C]PFO, 13.3 mg/kg) or of potassium [14C]perfluorooctanesulfonate [( 14C]PFOS, 3.4 mg/kg) to rats, cholestyramine fed daily as a 4% mixture in feed was shown to increase the total carbon-14 eliminated via feces and to decrease liver concentration of carbon-14. Rats were fed cholestyramine in feed for 14 days after administration of [14C]PFO and for 21 days after administration of [14C]PFOS. Control rats were administered radiolabeled fluorochemical but were not treated with cholestyramine. Cholestyramine treatment increased mean cumulative carbon-14 elimination in feces by 9.8-fold for rats administered [14C]PFO and by 9.5-fold for rats administered [14C]PFOS. After [14C]PFO, a mean of 4% of the dose of carbon-14 was in liver of cholestyramine-treated rats at 14 days versus 7.6% in control rats; after [14C]PFOS, 11.3% of the dose was in liver at 21 days versus 40.3% in control rats. After administration of either radiolabeled compound, plasma and red blood cell carbon-14 concentrations, which were relatively lower than liver concentrations, were also significantly reduced by cholestyramine treatment

  11. Determination of 90Sr, 14C, 134Cs and 137Cs activities in total diet

    International Nuclear Information System (INIS)

    Full text: According to the EU Recommendation dated 8 June 2000 On the Application of Article 36 of the EURATOM Treaty Concerning the Monitoring of the Levels of Radioactivity in the Environment for the Purpose of Assessing the Exposure of the Population as a Whole, 2000/473/EURATOM) the level of radioactivity in human diet is necessary to be measured for the assessment of radiological affects. Since there has not been any comprehensive work done on this subject in Turkey until now, we proposed a project for a detailed study, comprising the sampling and measurement of 90Sr, 14C, 134Cs and 137Cs in the human diet. Sr-90 and C-14 will be measured with Liquid Scintillation Spectrometry (LSS) and Cs-134 and Cs-137 with Gamma Ray Spectrometry. The sample preparation for Sr-90 and C-14 is a tedious process and should be investigated thoroughly. Sampling will also be a major concern due to the difficulty of finding suitable test subjects. The diets were collected by using double portion method over a three days period from the volunteer laboratory staff and methods for the radiochemical analysis of the diets for 90-Sr and 14-C were tested. The Sr-90 and C-14 activities founded are good agreement with the spiked activity. Real samples will be analyzed by validated methods for Sr-90, C-14, Cs-134 and Cs-137. Studies are still in progress. (author)

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

    International Nuclear Information System (INIS)

    Amount of residues of 14C-parathion in soil rice plants after application of the insecticide to soil were determined in four systems studied during five weeks: pots of soil with and without plants and open or enclosed by a transparent cover. Measurements of amounts volatilized and 14CO2 evolution from the pesticide were made in closed system without plants. The bound residues in soil and plants were also determined. Results indicated that parathion half life in a Gley Humic soil was about two weeks. Very little radiocarbon was taken up by rice plants; of this, more was found in shoots of plants enclosed, probably by collection of the volatilized material by plants. About 6% and 4% of the 14C-parathion were found as volatilized material and 14CO2, respectively after five weeks. Bound residues varied very little and reached a maximum of 22% in soil and in plants amounted to less than 2% at the final of the experiment. (Author)

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

    International Nuclear Information System (INIS)

    Tryptophan was obtained from biomass of the blue-green alga Synechococcus elongatus cultivated under 14CO2. After partial purification, the protein fraction was subjected to enzymatic hydrolysis using pronase. Semipreparative isolation of L-[U-14C]tryptophan was accomplished on a HPLC column of Separon S Hema 1000 CM, 2% ethanol were added to the eluent, and a precolumn packed with the basic anion exchanger Spheron 1000 DEAE was used. Always after the passage of L-[U-14C]tryptophan, the precolumn was decoupled. The substance was collected in 96% ethanol. After removing the solvent by vacuum evaporation, the sample was analyzed on a column packed with Separon SIX C18 in the eluent of 0.1M-NaH2PO4, 2% methanol. When the desired radiochemical purity was not attained, the sample was purified on Separon SIX C18 using 2% methanol. The final radiochemical purity achieved by using this method is 98%. (P.A.). 5 figs., 2 tabs., 4 refs

  14. Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates

    Science.gov (United States)

    Petrenko, Vasilii V.; Severinghaus, Jeffrey P.; Schaefer, Hinrich; Smith, Andrew M.; Kuhl, Tanner; Baggenstos, Daniel; Hua, Quan; Brook, Edward J.; Rose, Paul; Kulin, Robb; Bauska, Thomas; Harth, Christina; Buizert, Christo; Orsi, Anais; Emanuele, Guy; Lee, James E.; Brailsford, Gordon; Keeling, Ralph; Weiss, Ray F.

    2016-03-01

    Carbon-14 (14C) is incorporated into glacial ice by trapping of atmospheric gases as well as direct near-surface in situ cosmogenic production. 14C of trapped methane (14CH4) is a powerful tracer for past CH4 emissions from "old" carbon sources such as permafrost and marine CH4 clathrates. 14C in trapped carbon dioxide (14CO2) can be used for absolute dating of ice cores. In situ produced cosmogenic 14C in carbon monoxide (14CO) can potentially be used to reconstruct the past cosmic ray flux and past solar activity. Unfortunately, the trapped atmospheric and in situ cosmogenic components of 14C in glacial ice are difficult to disentangle and a thorough understanding of the in situ cosmogenic component is needed in order to extract useful information from ice core 14C. We analyzed very large (≈1000 kg) ice samples in the 2.26-19.53 m depth range from the ablation zone of Taylor Glacier, Antarctica, to study in situ cosmogenic production of 14CH4 and 14CO. All sampled ice is >50 ka in age, allowing for the assumption that most of the measured 14C originates from recent in situ cosmogenic production as ancient ice is brought to the surface via ablation. Our results place the first constraints on cosmogenic 14CH4 production rates and improve on prior estimates of 14CO production rates in ice. We find a constant 14CH4/14CO production ratio (0.0076 ± 0.0003) for samples deeper than 3 m, which allows the use of 14CO for correcting the 14CH4 signals for the in situ cosmogenic component. Our results also provide the first unambiguous confirmation of 14C production by fast muons in a natural setting (ice or rock) and suggest that the 14C production rates in ice commonly used in the literature may be too high.

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

    International Nuclear Information System (INIS)

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

  16. Metabolic breakdown of14 c-methomyl by soil fungi

    International Nuclear Information System (INIS)

    Three fungal species: Alternaria brassicola, helminthosporium sp. and verticillium agaricinum were incubated with radiolabelled methomyl (S14C-methyl-N-[(methylcarbamoyl)oxy] thioacetimidate ). After filtration, the amounts of radioactivity in tissues and filtrates were analyzed for metabolic products. Of the applied radioactivity, the 3 fungal species were capable of degrading 38.9%, 35.3% and 29.3% into hydrolytic metabolites, respectively. Thin layer chromatographic analysis of hydrolytic fractions showed that two metabolic products ( unknowns 1 and 11 ) having Rf values of 0.30 and 0.47 could be detected in addition to a polar compound which contained the major radioactivity. The chloroform fraction contained mainly the parent material.2 tab

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

    International Nuclear Information System (INIS)

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

  18. The degradation of [14C] parathion in two Brazilian soils

    International Nuclear Information System (INIS)

    Loss of [14C] parathion from two Brazilian soils was studied by measuring the parathion which could be extracted by a mixture of hexane and propanol and the 14CO2 evolved. Recovery of unchanged parathion decreased faster in the soil richer in organic matter (soil 1) from which more radiocarbon was evolved as CO2 than from the soil poorerin organic matter (soil 2). Evolution of CO2 from soil 1 decreased rapidly when the soil dried out but little effect of moisture content was observed in soil 2. Radiocarbon remaining in the soils was assayed by combustion after 234 days and the total recovered in soil 1 was 95.6% and, in soil 2,78.7%, sufficient to give almost complete recovery from both soils. (Author)

  19. 14C-Profenofos Residues in Milk and Milk Products

    International Nuclear Information System (INIS)

    Treatment of lactating goats with only one dose of 14C-ethoxy profenofos (17.9 mg/Kg) in gelatin capsules and then feeding normally, resulted in the presence of 0.5% of the radioactive insecticide residues in the milk collected through the fourteen successive days. The highest activity level was depicted at the first day and almost disappeared after two weeks. After processing, the analysis of milk products revealed difference in radioactive residue level according to the nature of the product and increased in the order: whey< skim < yoghurt < pasteurized milk < cheese< cream. TLC analysis of milk and milk products revealed the absence of the parent compound and the presence of 4 major metabolites, which were identified by co-chromatography with authentic compounds

  20. Asymmetric [14C]albumin transport across bullfrog alveolar epithelium

    International Nuclear Information System (INIS)

    Bullfrog lungs were prepared as planar sheets and bathed with Ringer solution in Ussing chambers. In the presence of a constant electrical gradient (20, 0, or -20 mV) across the tissue, 14C-labeled bovine serum albumin or inulin was instilled into the upstream reservoir and the rate of appearance of the tracer in the downstream reservoir was monitored. Two lungs from the same animal were used to determine any directional difference in tracer fluxes. An apparent permeability coefficient was estimated from a relationship between normalized downstream radioactivities and time. Results showed that the apparent permeability of albumin in the alveolar to pleural direction across the alveolar epithelial barrier is 2.3 X 10(-7) cm/s, significantly greater (P less than 0.0005) than that in the pleural to alveolar direction (5.3 X 10(-8) cm/s) when the tissue was short circuited. Permeability of inulin, on the other hand, did not show any directional dependence and averaged 3.1 X 10(-8) cm/s in both directions. There was no effect on radiotracer fluxes permeabilities of different electrical gradients across the tissue. Gel electrophoretograms and corresponding radiochromatograms suggest that the large and asymmetric isotope fluxes are not primarily due to digestion or degradation of labeled molecules. Inulin appears to traverse the alveolar epithelial barrier by simple diffusion through hydrated paracellular pathways. On the other hand, [14C]albumin crosses the alveolar epithelium more rapidly than would be expected by simple diffusion. These asymmetric and large tracer fluxes suggest that a specialized mechanism is present in alveolar epithelium that may be capable of helping to remove albumin from the alveolar space

  1. Redistribution of paclobutrazol-14C in soil and plant

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Maria Aparecida; Tornisielo, Valdemar Luiz; Regitano, Jussara Borges [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Ecotoxicologia]. E-mail: macosta@cena.usp.br; vltorrnis@cena.usp.br; regitano@cena.usp.br

    2007-07-01

    Paclobutrazol (PBZ) is important to the mango culture since it works as a growth regulator that inhibits gibberellins synthesis controlling the growth of the trees and thus reducing pruning and manipulation during cultivation. Although PBZ has been used for years in mango in Brazil, there are no studies evaluating its environmental fate under Brazilian conditions. Therefore, the objective of the present work is to evaluate the redistribution of PBZ and its metabolites in soil and plant. For this experiment, radiolabeled ({sup 14}C-PBZ) was used once this technique allows detention of minimum amounts of residues in both soil and plant. In addition, plants were cultivated in vessels (100 L and 1 plant /vessel) and the PBZ were applied to the soils at the recommended rate of 1,0 kg ha{sup -1}, having radioactive concentration of 2,0 MBq/vessel. In order to evaluate PBZ redistribution, the volumes of water percolated with rainfall and senescent leaves were collected to monitor their {sup 14}C-residue concentration by liquid scintillation spectrometry (LSS). In parallel, the sorption and leaching potential of PBZ was determined in order to support the previous study. The results showed that PBZ presented relatively low mobility (0.12 % of the applied amount) and high sorption (91.9 % of the applied amount) in the studied soil, being minimal its leached amount; and that majority of the soil applied radioactivity were redistributed in the plant leaves (1.08% of the applied amount). Needing more inquiries in relation to the contamination of the soil and rain water percolated in period of September, 2nd, 2006 to January, 8th, 2007 was of the 0.06% in relation applied radioactivity being very next the radioactivity to deep, indicating that the product still is not being leached during rains. (author)

  2. Mass spectrometric detection of radiocarbon for dating applications

    Energy Technology Data Exchange (ETDEWEB)

    Synal, H.-A., E-mail: synal@phys.ethz.ch [ETH Zurich, Laboratory of Ion Beam Physics, Building HPK, 8093 Zurich (Switzerland); Schulze-Koenig, T.; Seiler, M.; Suter, M.; Wacker, L. [ETH Zurich, Laboratory of Ion Beam Physics, Building HPK, 8093 Zurich (Switzerland)

    2013-01-15

    Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far, standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which, however, can be completely eliminated in charge changing processes at high ion beam energies (MeV) [1,2]. Here, we present a novel type mass spectrometry system for radiocarbon analyses. Radiocarbon dating was performed using 45 keV {sup 14}C ions from the ion source and a molecule dissociation unit kept at ground potential. This proof-of-principle experiment demonstrates for the first time the feasibility of mass spectrometric radiocarbon dating without an accelerator. The results obtained will be the basis of an optimized design for a radiocarbon dating instrument comparable in size, complexity and cost to standard mass spectrometers.

  3. The use of natural 14C as a tracer to identify the incorporation of younger material into the organic component of sediments from the Carpentaria Basin, Australia

    International Nuclear Information System (INIS)

    A 'chemically inert' organic fraction was isolated from samples taken from a sediment core that was collected from the Gulf of Carpentaria, lying between Australia and Papua New Guinea. Accelerator mass spectrometry (AMS) 14C ages obtained from this fraction become younger with depth, the maximum 14C concentration being 107% M, then become older again. The shape of the plot of apparent 14C age with depth can be compared to a typical concentration plot of a compound being passed through a chromatographic column. The shape of the so-called natural chromatogram has a relatively sharp leading edge, then gradually tails off. Stable carbon isotope values indicate that the material is most probably a non polar compound (or mixture) of yet unknown origin. (author)

  4. The incorporation of [14C] glucosamine into dolichol diphosphate N-acetyl [14C] glucosamine by unbroken liver cells in culture

    International Nuclear Information System (INIS)

    Incubation of whole Chang liver cells with D-[1-14C]glucosamine results in incorporation of radioactivity into both proteins and lipids. A minor (approximately 3%) amount of the labelled lipid has the chromatographic, solubility and chemical properties of dolichol diphosphate N-acetylglucosamine. A similar compound is formed when membrane preparations of the cells are incubated with UDP-N-acetyl [14C]glucosamine. The same membrane fractions catalyse the transfer of [14C]-mannose from GDP-[14C]mannose to dolichol phosphate. (orig.)

  5. Simulation of 14C in IAP/LASG L30T63 Ocean Model

    Institute of Scientific and Technical Information of China (English)

    LI Qingquan; SHI Guangyu

    2005-01-01

    14C plays an important role in the study of ocean circulation and anthropogenic CO2. Radioactive 14C is usually used in ocean carbon circulation model to test the physical performance of model. In the present paper, a 14C model is established and coupled with the IAP/LASG L30T63 global ocean circulation model to simulate the distribution of natural 14C in oceans and the penetration and uptake of 14C in oceans after industrial revolution and nuclear bomb test. The simulation of natural 14C reveals the basic characteristics of oceanic ventilation. However, simulation value is "younger" than observation in the Pacific and Indian Oceans, and "older" than observation in the Atlantic deep ocean. The simulation of bomb 14C agrees well with GEOSECS observation, but the volume inventory and averaged penetration depth of bomb 14C in oceans are smaller than observation. The probable reasons for these discrepancies are analyzed.

  6. Defective [U-14 C] palmitic acid oxidation in Duchenne muscular dystrophy

    International Nuclear Information System (INIS)

    Compared with normal skeletal muscle, muscle from patients with Duchenne dystrophy had decreased [U-14 C] palmitic acid oxidation. [1-14 C] palmitic acid oxidation was normal. These results may indicate a defect in intramitochondrial fatty acid oxidation

  7. Urvina Bay, Galapagos Coral Radiocarbon (delta 14C) Data for 1956 to 1982

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Urvina Bay coral radiocarbon (14C) timeseries. (90 deg W, 0.5 deg S) Coral radiocarbon (Delta-14C) on untreated, low-speed drilled samples. Precision is +/- 4 per...

  8. Radiometric dating methods

    International Nuclear Information System (INIS)

    The general principle of isotope dating methods is based on the presence of radioactive isotopes in the geologic or archaeological object to be dated. The decay with time of these isotopes is used to determine the 'zero' time corresponding to the event to be dated. This paper recalls the general principle of isotope dating methods (bases, analytical methods, validation of results and uncertainties) and presents the methods based on natural radioactivity (Rb-Sr, Sm-Nd, U-Pb, Re-Os, K-Ar (Ar-Ar), U-Th-Ra-210Pb, U-Pa, 14C, 36Cl, 10Be) and the methods based on artificial radioactivity with their applications. Finally, the methods based on irradiation damages (thermoluminescence, fission tracks, electron spin resonance) are briefly evoked. (J.S.)

  9. Production and characterization of [14C]protein A, a long-lived immunological reagent

    International Nuclear Information System (INIS)

    A procedure for the production of [14C]protein A is described which involves reductive methylation of lysine residues with [14C]formaldehyde and NaCNBH3. The binding of [14C]protein A to IgG is apparently unaltered, as determined by competitive binding studies. The use of [14C]protein A may be preferred to that of 125I-protein A when a radioactive label with a long half-life is desirable. (Auth.)

  10. Radiocarbon dating and compositional analysis of pre-Columbian human bones

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E., E-mail: andrade@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Solís, C.; Canto, C.E.; Lucio, O.G. de [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Chavez, E. [ESIME-Z, Instituto Politécnico Nacional, ALM Zacatenco, 07738 México D.F. (Mexico); Rocha, M.F.; Villanueva, O.; Torreblanca, C.A. [Centro INAH Zacatecas, Miguel Auza No. 205, Col. Centro, Zacatecas/Zacatecas CP 98000 (Mexico)

    2014-08-01

    Analysis of ancient human bones found in “El Cóporo”, an archaeological site in Guanajuato, Mexico; were performed using a multi techniques scheme: {sup 14}C radiocarbon dating, IBA (Ion Beam Analysis), SEM-EDS (Scanning Electron Microscope Energy Dispersive X-ray Spectroscopy). We measured the elemental composition of the bones, especially some with a superficial black pigmentation. Soil samples collected from the burial place were also analyzed. The {sup 14}C dating was performed with a new High Voltage Europe 1 MV Tandentron Accelerator Mass Spectrometer (AMS) recently installed in the IFUNAM (Instituto de Física, Universidad Nacional Autónoma de México). The radiocarbon dating allowed us to determine the date of death of the individual in a period between the year 890 and 975 AD, which is consistent with the late period of the Cóporo civilization. The element sample analysis of bones with the surface black pigmentation show higher levels of Fe, Mn and Ba compared when bone’s black surface was mechanically removed. These three elements were found in soil samples from the skeleton burial place. These results indicate more likely that the bone black coloration is due to a postmortem alteration occurring in the burial environment.

  11. Radiocarbon dating and compositional analysis of pre-Columbian human bones

    International Nuclear Information System (INIS)

    Analysis of ancient human bones found in “El Cóporo”, an archaeological site in Guanajuato, Mexico; were performed using a multi techniques scheme: 14C radiocarbon dating, IBA (Ion Beam Analysis), SEM-EDS (Scanning Electron Microscope Energy Dispersive X-ray Spectroscopy). We measured the elemental composition of the bones, especially some with a superficial black pigmentation. Soil samples collected from the burial place were also analyzed. The 14C dating was performed with a new High Voltage Europe 1 MV Tandentron Accelerator Mass Spectrometer (AMS) recently installed in the IFUNAM (Instituto de Física, Universidad Nacional Autónoma de México). The radiocarbon dating allowed us to determine the date of death of the individual in a period between the year 890 and 975 AD, which is consistent with the late period of the Cóporo civilization. The element sample analysis of bones with the surface black pigmentation show higher levels of Fe, Mn and Ba compared when bone’s black surface was mechanically removed. These three elements were found in soil samples from the skeleton burial place. These results indicate more likely that the bone black coloration is due to a postmortem alteration occurring in the burial environment

  12. Synthesis of two 14C-labeled catechol-o-methyltransferase inhibitors

    International Nuclear Information System (INIS)

    14C-labelled 3-(3,4-dihydroxy-5-nitrophenylmethylidene)-2,4-pentanedione and 14C-labelled E-N,N-diethyl-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide have been synthesized from [carbonyl-14C]vanillin. (author)

  13. Disposition of [14C]γ-cyclodextrin in germ-free and conventional rats

    NARCIS (Netherlands)

    Bie, A.T.H.J. de; Ommen, B. van; Bär, A.

    1998-01-01

    The absorption, disposition, metabolism, and excretion of 14C-labeled γ-cyclodextrin ([14C]γ-CD) was examined in four separate experiments with Wistar rats. In experiment 1, [14C]γ-CD (25 μCi, 600 mg/kg body wt) was administered intravenously to four male and four female conventional rats. In experi

  14. Progress in the development of methods for the determination of 14C

    International Nuclear Information System (INIS)

    Two methods are described in detail: liquid scintillation counting of 14C in the form of benzene, and liquid scintillation counting of 14C in carbonate solution. The former method is used, for example, to monitor atmospheric 14C in CO2, the latter, to monitor gaseous discharges from nuclear power plants. (P.A.)

  15. Measurement of {sup 14}C/{sup 12}C ratios in plant samples that were affected by the Fukushima nuclear accident

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Risa; Inoue, Aki; Muramatsu, Yasuyuki [Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo, 171-8588 (Japan); Matsuzaki, Hiroyuki [The University of Tokyo, Micro Analysis Laboratory, Tandem Accelerator, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032 (Japan)

    2014-07-01

    In nature, {sup 14}C is produced by cosmic ray reactions in the upper atmosphere, and its production is influenced by the flux of cosmic rays. This nuclide is also released into the atmosphere by anthropogenic sources such as nuclear weapons testing and a nuclear accident. The produced {sup 14}C immediately becomes {sup 14}CO{sub 2} and it is absorbed by plants through photosynthesis. Therefore, plants are reflected by atmospheric {sup 14}C levels at that time. Although there are many papers reporting the release of several nuclides by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident occurred in March, 2011, it is not clear whether appreciable amounts of {sup 14}C were released into the environment due to the accident. In this study, we focus on {sup 14}C levels in plant samples collected from several locations in Fukushima Prefecture (Okuma, Namie, Iitate, and Fukushima-city) and examine the possible influence on the {sup 14}C revels in plants. Since cedars and pines are evergreen, the leaves should have been contaminated at the time of the accident. We analyzed old leaves, which were grown before the accident, and new leaves, which were grown after the accident. Both old and new leaves were collected in the same branch. In order to compare delta {sup 14}C values in leaves collected from Fukushima Prefecture with background values, we have used plant samples collected from remote areas such as Chiba and Niigata Prefectures. The samples were dried, pulverized in a blender and homogenized. Then samples were placed between copper oxide wires in a quarts tube, burned and oxidized. The produced CO{sub 2} mixed gases were purified in a vacuum line. To prepare a graphite target for AMS, the purified CO{sub 2} was reduced. {sup 14}C/{sup 12}C ratio in the graphite was measured by AMS at the University of Tokyo or Japan Atomic Energy Agency. Analytical results showed that delta {sup 14}C values in plant samples collected from the highly contaminated areas such as

  16. Degradation and residues of trifluralin and metalaxyl in soils treated with 14C-trifluralin and 14C-metalaxyl, under laboratory conditions

    International Nuclear Information System (INIS)

    The behavior of the herbicide 14C-trifluralin and the fungicide 14C-metalaxyl was studied under laboratory conditions in Red Latosol and Yellow Red Podzol soils in samples Kept flooded, sterilized and with humidity equivalent to 60% of the water field capacity. The degradation of both pesticides is discussed. (M.A.C.)

  17. 14C as a tool for evaluating riverine POC sources and erosion of the Zhujiang (Pearl River) drainage basin, South China

    International Nuclear Information System (INIS)

    Radiocarbon can serve as a powerful tool for identifying sources of organic carbon and evaluating the erosion intensity in river drainage basins. In this paper we present 14C-AMS measurements of particulate organic carbon (POC) collected from the three major tributaries of the Zhujiang (Pearl River) system: the Xijiang (Western River), Beijiang (Northern River) and Dongjiang (Eastern River) rivers. Furthermore, we discuss the distribution of POC 14C apparent ages and the related watersheds erosion of these rivers. Results yield Δ14C values of -425 per mille to -65 per mille which indicate that the 14C apparent ages of suspended POC in the entire area are in the range of 540-4445 years. The POC apparent ages from Xijiang are mostly between 2000 and 4000 years, while in Dongjiang they mostly range from 540 to 1010 years. These 14C apparent ages indicate that the watershed erosion of the Xijiang is more severe than that of the Dongjiang. This is in agreement with other data showing deeper erosion in Xijiang due to human activities.

  18. Characterization of hemoglobin adduct formation in mice and rats after administration of [14C]butadiene or [14C]isoprene

    International Nuclear Information System (INIS)

    Occupational exposures to 1,3-butadiene or isoprene occur through their use in the manufacture of rubber and other related polymer products. The purpose of this study was to determine if butadiene or isoprene administration would result in the formation of adducts with blood hemoglobin (Hb), and if such adducts can be used as a measure of previous exposure(s). Male B6C3F1 mice and male Sprague-Dawley rats were injected intraperitoneally with 1, 10, 100, or 1000 mumol [14C]butadiene or 0.3, 3.0, 300, 1000, or 3000 mumol [14C]isoprene per kilogram body weight. Animals were killed 24 hr later. Globin was isolated from blood samples and was analyzed for 14C by liquid scintillation spectroscopy. Hb adduct formation was linearly related to administered doses up to 100 mumol [14C]butadiene or 500 mumol [14C]isoprene per kilogram body weight for mice and rats, respectively. For [14C]butadiene, the efficiency of Hb adduct formation in mice and rats within the linear response range was 0.177 +/- 0.003 and 0.407 +/- 0.019 (pmol of 14C-adducts/mg globin)/(mumol of retained [14C]butadiene/kg body wt), respectively (mean +/- SE; n = 18). For [14C]isoprene, these values for mice and rats were 0.158 +/- 0.035 and 0.079 +/- 0.016 (pmol of 14C-adducts/mg globin)/(mumol of retained [14C]isoprene/kg body wt), respectively (mean +/- SE; n = 12). Hb adducts also accumulated linearly after repeated daily administration of 100 mumol [14C]butadiene or 500 mumol [14C]isoprene per kilogram body wt to mice and rats, respectively, for 3 days. [14C]Butadiene-derived Hb adducts in blood showed lifetimes of approximately 24 and approximately 65 days for mice and rats, respectively, which correlate with the reported lifetimes for red blood cells in these rodent species. Thus, levels of butadiene- or isoprene-derived adducts on Hb in circulating blood may be a useful measure of prior repeated exposures to these compounds

  19. Depletion of [14C]clorsulon in cows' milk

    International Nuclear Information System (INIS)

    Radioactive residue levels were determined in milk and plasma of Holstein cows dosed once with an oral suspension of 14C-labeled clorsulon at 7 mg/kg of body weight. Average milk residue levels decreased from 0.54 ppm at 0.9 day postdose to 0.004 ppm at 6.9 days postdose with a half-life of 0.81 day. The drug residue was isolated by a batch adsorption method on an affinity agarose gel of carbonic anhydrase-Sepharose 4B and analyzed by HPCL-reverse isotope dilution assay (RIDA). This novel method greatly simplified the extraction of drug residue from milk and provided pure drug residue isolates. RIDA results of the isolates indicated that the unchanged drug was the major residue component in milk at 0-4 days postdose accounting for 56-99% of the total radioactive residue. Depletion half-life of the parent drug was 0.82 day, in close agreement with that of the total residue in milk. About 0.7% of the dose was recovered in the milk during the 6.9-day period

  20. Biodegradation of14 C-lindane by some soil fungi

    International Nuclear Information System (INIS)

    In a culture medium incorporated with 14 C-labelled lindane, the 3 soil fungi helminthosporium sp., alternaria brassicola, and verticillium agaricinum were incubated for 10 days. Most of the recovered radioactivity was found to be maintained mainly in the medium of helminthosporium and alternaria but in case of verticillium the majority was associated with the mat. The 3 fungal species showed degradation capacity of 6.1, 5.1 and 3.2% of the total recovered radioactivity radioactivity as hydrolytic products. TLC chromatographic analysis of chloroform fractions revealed the presence of only unchanged lindane either in medium of mat. The aqueous fractions of the 3 fungal species, demonstrated three degraded products (unknown ι,π and tri) having Rf values of 0.40 - 0.47, 0.66 - 0.73, and 0.87 in addition to a polar compound (Rf = 0.07) with the major radioactivity. A certain percentage of radiocarbon 6.7, 5.7 and 30.3% of the mats of helminthosporium, alternria and verticillium, respectively.2 tab

  1. Fate of 14C-carbofuran in lactating goats

    International Nuclear Information System (INIS)

    Radiocarbon labeled carbofuran was administered orally to lactating goats at 0.03 mg/kg (single dose), 0.5 and 1.0 mg/kg/day for 7 days, and at 5.0 ppm in the diet (2 kg feed intake/day basis) for 15 days. Radioactive residues were rapidly excreted in the urine after treatment. The major residue identified in urine of the treated goats was carbofuran phenol, a non-toxic metabolite. Only about 1% of the doses was eliminated in the feces of the treated goats. Residues of (14C)carbofuran were secreted into milk, but these residues were in all cases very low. Radioactive residue occurred in tissues at low levels, with patterns as follows: omental fat>liver>subcutaneous fat>kidney>brain>heart>biceps femoris>longissimus dorsi. The residue stored in fat was identified as carbofuran. The liver contained hydroxy carbofuran and one unidentified metabolite but no carbofuran. The other tissues contained only phenolic metabolites. These studies strongly indicate that proper carbofuran use in rice in the Philippines will present no risks to goats that consume treated crop residues, or to humans who consume meat or milk from exposed animals. (author)

  2. Fate of 14C-Labelled Triazine Herbicides in Plants

    International Nuclear Information System (INIS)

    The resistance of certain plant species to triazines is referred to their ability to metabolize the herbicide. In the case of the chloro-triazines the conversion to the 2-hydroxy analogue, a non-phytotoxic product, has been described in the literature already. Studies which have been devoted to the metabolic breakdown of methylmercaptotriazines revealed a conversion to the 2-hydroxy compound to a smaller extent and in a way different from that established with the chloro-triazines. The in vitro oxidation of prometryne (2-methylmercapto-4, 6-bisisopropylamino-striazine) yields the sulphoxy and sulphono analogues which easily hydrolyse to 2-hydroxypropazine. The occurrence of these compounds in peas injected with 14C-prometryne could be established. Some recent findings concerning the occurrence of further metabolites with an intact triazine ring suggest that dealkylation or deamination of the side chains in the 4- and 6-position have to be considered too. Methods used in studying the metabolism of triazines and for the determination of 14CO2 released from treated plants are discussed. (author)

  3. Photolysis of 14C-sulfadiazine in water and manure.

    Science.gov (United States)

    Sukul, Premasis; Lamshöft, Marc; Zühlke, Sebastian; Spiteller, Michael

    2008-03-01

    Photolysis of 14C-sulfadiazine in aqueous solution under simulated sunlight followed first-order kinetics. The impact of H2O2, humic acid, fulvic acid and acetone to enhance the photodegradation of sulfadiazine (SDZ) was studied. Six photoproducts, 4-OH-SDZ, 5-OH-SDZ, N-formyl-SDZ, 4-[2-iminopyrimidine-1(2H)-yl] aniline, 2-aminopyrimidine, and aniline were identified. Extrusion of SO2 was found to be the main degradation process during irradiation. These photoproducts can occur in water and soil upon sunlight exposure, when soil is treated with SDZ contained in manure. Due to photodegradation the experimental half-life of the SDZ in water was 32h and in the presence of photosensitizers the half-life values were 19.3-31.4h, 17.2-31.4h, 12.6-29.8h, and 3.8-30.7h for H2O2, humic acid, fulvic acid, and acetone, respectively depending on the concentration of the photosensitizers. The presence of photosensitizers markedly reduced SDZ persistence, indicating that indirect photolytic processes are important factors governing the photodegradation of SDZ in aqueous environments. Investigation revealed further persistence behavior of SDZ in manure. The half-life value of SDZ in manure was 158h. PMID:18076971

  4. Synthesis of [14C]imidazole ring labeled metiamide, cimetidine and impromidine

    International Nuclear Information System (INIS)

    The radiosynthesis of imidazole ring labeled [14C]metiamide, [14C]cimetidine and [14C]impromidine are described involving the reaction of the key common intermediate 2-[[(4-methyl-1H-[2-14C]imidazol-5-yl)methyl]thio]ethanamine with methyl isothiocyanate, dimethyldithiocyanoiminocarbonate/methylamine and the novel dihydroimidazodiazepine, respectively. The ring labeled precursor was prepared in five steps from potassium [14C]cyanide in an overall radiochemical yield of 63%, and having a specific activity of 9.3 mCi/mmol. (author)

  5. A 22,000 14C year BP sediment and pollen record of climate change from Laguna Miscanti (23°S), northern Chile

    Science.gov (United States)

    Grosjean, M.; van Leeuwen, J. F. N.; van der Knaap, W. O.; Geyh, M. A.; Ammann, B.; Tanner, W.; Messerli, B.; Núñez, L. A.; Valero-Garcés, B. L.; Veit, H.

    2001-02-01

    Lake sediments and pollen, spores and algae from the high-elevation endorheic Laguna Miscanti (22°45'S, 67°45'W, 4140 m a.s.l., 13.5 km 2 water surface, 10 m deep) in the Atacama Desert of northern Chile provide information about abrupt and high amplitude changes in effective moisture. Although the lack of terrestrial organic macrofossils and the presence of a significant 14C reservoir effect make radiocarbon dating of lake sediments very difficult, we propose the following palaeoenvironmental history. An initial shallow freshwater lake (ca. 22,000 14C years BP) disappeared during the extremely dry conditions of the Last Glacial Maximum (LGM; 18,000 14C years BP). That section is devoid of pollen. The late-glacial lake transgression started around 12,000 14C years BP, peaked in two phases between ca. 11,000 and <9000 14C years BP, and terminated around 8000 14C years BP. Effective moisture increased more than three times compared to modern conditions (˜200 mm precipitation), and a relatively dense terrestrial vegetation was established. Very shallow hypersaline lacustrine conditions prevailed during the mid-Holocene until ca. 3600 14C years BP. However, numerous drying and wetting cycles suggest frequent changes in moisture, maybe even individual storms during the mid-Holocene. After several humid spells, modern conditions were reached at ca. 3000 14C years BP. Comparison between limnogeological data and pollen of terrestrial plants suggest century-scale response lags. Relatively constant concentrations of long-distance transported pollen from lowlands east of the Andes suggest similar atmospheric circulation patterns (mainly tropical summer rainfall) throughout the entire period of time. These findings compare favorably with other regional paleoenvironmental data.

  6. Nine-step synthesis of (/sup 14/C)flupirtine maleate labeled in the pyridine ring

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-01-01

    A nine-step procedure for microscale synthesis of ethyl 2-amino-6-brace((4-fluorophenyl)methyl)aminobrace-3-pyridinyl-2,6-/sup 14/C carbamate maleate, (/sup 14/C)flupirtine maleate, was developed. The synthesis started with potassium cyanide-/sup 14/C and 1,3-dibromopropane making the following intermediates: glutarontrile-/sup 14/C, glutarimide-/sup 14/C, 2,6-dichloropyridine-2,6-/sup 14/C, 2,6-dichloro-3-nitro-pyridine-2,6-/sup 14/C, 2-amino-3-nitro-6-chloropyridine-2,6-/sup 14/C, 2-amino-3-nitro-6-(p-fluorobenzylamino)pyridine-2,6-/sup 14/C, 2,3-diamino-6-(p-fluorobenzylamino)pyridine-2,6-/sup 14/C, and ethyl 2-amino-6-brace((4-fluorophenyl)-methyl)aminobrace-3-pyridinyl-2,6-/sup 14/C carbamic acid ester hydrochloride. The overall yield was 6.3% (5.4 mCi), and the radioactivity was 99.8% as determined by high performance liquid chromatography and liquid scintillation counting.

  7. A nine-step synthesis of [14C]flupirtine maleate labeled in the pyridine ring

    International Nuclear Information System (INIS)

    A nine-step procedure for microscale synthesis of ethyl 2-amino-6-brace[(4-fluorophenyl)methyl]aminobrace-3-pyridinyl-2,6-14C carbamate maleate, [14C]flupirtine maleate, was developed. The synthesis started with potassium cyanide-14C and 1,3-dibromopropane making the following intermediates: glutarontrile-14C, glutarimide-14C, 2,6-dichloropyridine-2,6-14C, 2,6-dichloro-3-nitro-pyridine-2,6-14C, 2-amino-3-nitro-6-chloropyridine-2,6-14C, 2-amino-3-nitro-6-(p-fluorobenzylamino)pyridine-2,6-14C, 2,3-diamino-6-(p-fluorobenzylamino)pyridine-2,6-14C, and ethyl 2-amino-6-brace[(4-fluorophenyl)-methyl)aminobrace-3-pyridinyl-2,6-14C carbamic acid ester hydrochloride. The overall yield was 6.3% (5.4 mCi), and the radioactivity was 99.8% as determined by high performance liquid chromatography and liquid scintillation counting. (author)

  8. Studies on the distribution of 14C-labelled PCB in the body, 4

    International Nuclear Information System (INIS)

    This paper is a report of 14C-PCB distribution series in animals. We reported the results of the distribution of 14C-PCB from birds, fish and shell in the previous experiments, and we have obtained some results from present experiment. This time interperito neal injection of 14C-PCB solution was carried to mice, and the results were as follows; Excretion of 14C-PCB as radioactivity was at its maximum about 6 hr. after medication. Excretive ratio was 87.20% for 24 hr, but 72.43% of radioactivity was excreted within 12hr. The result of radiopaperchromatography showed that 14C-PCB was not changeable in the fecus after medication, being Rf = 0.92 in comparison with standard 14C-PCB. 14C-PCB distributed throughout the body of mice in 24 hr. and at least remained over till 480 hr. in adipose tissues of mice after single medication. (auth.)

  9. Kinetics of Beta-14[14C] Carotene in a Human Subject Using Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dueker, S.R.; Lin, Y.; Follett, J.R.; Clifford, A.J.; Buchholz, B.A.

    2000-01-31

    {beta}-Carotene is a tetraterpenoid distributed widely throughout the plant kingdom. It is a member of a group of pigments referred to as carotenoids that have the distinction of serving as metabolic precursors to vitamin A in humans and many animals [1,2]. We used Accelerator Mass Spectrometry (AMS) [3] to determine the metabolic behavior of a physiologic oral dose of {beta}-[{sup 14}C]carotene (200 nanoCuries; 0.57 {micro}mol) in a healthy human subject. Serial blood specimens were collected for 210-d and complete urine and feces were collected for 17 and 10-d, respectively. Balance data indicated that the dose was 42% bioavailable. The absorbed {beta}-carotene was lost slowly via urine in accord with the slow body turnover of {beta}-carotene and vitamin A [4]. HPLC fractionation of plasma taken at early time points (0-24-h) showed the label was distributed between {beta}-carotene and retinyl esters (vitamin A) derived from intestinal metabolism.

  10. Determination of the Tissue Distribution and Excretion by Accelerator Mass Spectrometry of the Nonadecapeptide 14C-Moli1901 in Beagle dogs after Intratracheal Instillation

    Energy Technology Data Exchange (ETDEWEB)

    Rickert, D E; Dingley, K H; Ubick, E; Dix, K J; Molina, L

    2004-07-02

    Administration of {sup 14}C-Moli1901 (duramycin, 2622U90), a 19 amino acid polycyclic peptide by intratracheal instillation (approximately 100 {micro}g) into the left cranial lobe of the lung of beagle dogs resulted in retention of 64% of the dose in the left cranial lobe for up to 28 days. In this study, we used accelerator mass spectrometry (AMS) to quantify Moli901 following administration of only 0.045 {micro}Ci of {sup 14}C-Moli901 per dog. Limits of quantitation of AMS were 0.03 (urine) to 0.3 (feces) ng equiv. Moli1901/g. Whole blood and plasma concentrations of {sup 14}C were <5ng/ml at all times after the dose. Concentrations of {sup 14}C in whole blood and plasma declined over the first day after the dose and rose thereafter, with the rise in plasma concentrations lagging behind those in whole blood. During the first 3 days after the dose, plasma accounted for the majority of {sup 14}C in whole blood, but after that time, plasma accounted for only 25-30% of the {sup 14}C in whole blood. Tissue (left and right caudal lung lobe, liver, kidney, spleen, brain) and bile concentrations were low, always less than 0.25% the concentrations found in the left cranial lung lobe. Approximately 13% of the dose was eliminated in urine and feces in 28 days, with fecal elimination accounting for about 10% of the dose. The data presented here are consistent with that obtained in other species. Moli1901 is slowly absorbed and excreted from the lung, and it does not accumulate in other tissues. Moli1901 is currently in the clinic and has proven to be safe in single dose studies in human volunteers and cystic fibrosis patients by the inhalation route. No information on the disposition of the compound in humans is available. This study in dogs demonstrates the feasibility of obtaining that information using {sup 14}C-Moli1901 and AMS.

  11. Insights from 14C into C loss pathways in degraded peatlands

    Science.gov (United States)

    Evans, Martin; Evans, Chris; Allott, Tim; Stimson, Andrew; Goulsbra, Claire

    2016-04-01

    Peatlands are important global stores of terrestrial carbon. Lowered water tables due to changing climate and direct or indirect human intervention produce a deeper aerobic zone and have the potential to enhance loss of stored carbon from the peat profile. The quasi continuous accumulation of organic matter in active peatlands means that the age of fluvial dissolved organic carbon exported from peatland systems is related to the source depth in the peat profile. Consequently 14C analysis of DOC in waters draining peatlands has the potential not only to tell us about the source of fluvial carbon and the stability of the peatland but also about the dominant hydrological pathways in the peatland system. This paper will present new radiocarbon determinations from peatland streams draining the heavily eroded peatlands of the southern Pennine uplands in the UK. These blanket peatland systems are highly degraded, with extensive bare peat and gully erosion resulting from air pollution during the industrial revolution, overgrazing, wildfire and climatic changes. Deep and extensive gullying has significantly modified the hydrology of these systems leading to local and more widespread drawdown of water table. 14C data from DOC in drainage waters are presented from two catchments; one with extensive gully erosion and the other with a combination of gully erosion and sheet erosion of the peat. At the gully eroded site DOC in drainage waters is as old as 160 BP but at the site with extensive sheet erosion dates of up to 1069 BP are amongst the oldest recorded from blanket peatland globally These data indicate significant degradation of stored carbon from the eroding peatlands. Initial comparisons of the 14C data with modelled water table for the catchments and depth-age curves for catchment peats suggests that erosion of the peat surface, allowing decomposition of exposed older organic material is a potential mechanism producing aged carbon from the eroded catchment. This

  12. Lethal Effect on Bacterium of Decay of Incorporated Radioactive Atoms (3H, 14C, 32P)

    International Nuclear Information System (INIS)

    The biological effect of decay of 3H, 14C and 32P incorporated into a bacterium depends on the nature of the organic molecule labelled, on the position of the isotope within it and on the isotope itself. In sum, results obtained to date show that: The decay of 3H atoms incorporated into certain macromolecules of a bacterium causes sterilization through ionization by the ß- particle emitted; transmutation is of negligible importance. This self-irradiation is comparable in effect with X-rays and is affected in a similar manner by the same factors: temperature, presence of a radioprotector, radiosensitivity of the strain. Decay of 14C or 32P atoms incorporated into bacterial DNA is lethal because of the transmutation effect; ionizations produced by emitted ß- particles may be disregarded. Survival curves for 32P transmutations depend on the experimental conditions. Some of the results obtained with 32P are similar to those obtained with X-rays, e.g. effects of temperature, radical capture and oxygen, while others are similar to those of u.v. light, e.g., effect of growth conditions. Comparative tests made with 32P indicate that the recoil energy of transmutation is not the phenomenon responsible for the lethal effect observed. Comparison of the results obtained after X-irradiation or decay of 3H or 32P incorporated into the DNA of bacteria of the same strain of E. coli shows that the efficiency of a 32P transmutation is about four times greater than that of an ionization produced at random within the same DNA. (author)

  13. A rapid microwave induced synthesis of [carboxyl-14C]-nicotinic acid (vitamin B3) and [carbonyl-14C]-nicotinamide using K14CN

    International Nuclear Information System (INIS)

    Microwave assisted direct aromatic substitution of 3-bromopyridine with K14CN as the cyanide source and catalytic amount of tetrabutylammonium bromide afforded [3-14C]-cyanopyridine 3 in 90% yield. Microwave assisted hydrolysis of 3 with a mixture of concentrated hydrochloric acid and propionic acid afforded [carboxyl-14C]-nicotinic acid in 95% yield whereas microwave assisted hydrolysis of 3 with a mixture of concentrated sulfuric acid and propionic acid afforded [carbonyl-14C]-nicotinamide in 85% yield. (author)

  14. Preparation of /sup 14/C-labelled AMP, ADP and ATP from adenine-8-/sup 14/C by using Brevibacterium ammoniagenes

    Energy Technology Data Exchange (ETDEWEB)

    Pande, V.N. (Bhabha Atomic Research Centre, Bombay (India). Biochemistry and Food Technology Div.)

    1985-04-01

    High radiochemical yields of /sup 14/C-labelled adenine nucleotides (AMP, 4.6%, ADP, 15.5% and ATP 59.5%) could be obtained by growing the cells of Brevibacterium ammoniagenes in the presence of /sup 14/C-adenine. The specific radioactivity of the adenine nucleotides almost reached that of /sup 14/C-adenine indicating negligible dilution of the label. The procedure is convenient and especially suited for commercial preparation of the radiolabelled nucleotides directly from labelled adenine. Preliminary results indicate that the organism could also be used for the preparation of radiolabelled guanine nucleotides.

  15. Formation and bio release of bound residues of [14 C]-lindane and [14 C]-parathion in two Brazilian soils

    International Nuclear Information System (INIS)

    This work studied the extractable and bound residues formation of 14 C-lindane and 14 C-parathion immediately after application and after 3 months of interaction of the pesticides with the soils. Metabolism, bio release, and the possible bioavailability of bound residues were studied by employing bio meter flasks which allowed a relative comparison of the behaviour of the two different 14 C-pesticides, by a balance of the applied or present radiocarbon in the soils after the bio tests. (author)

  16. Radiometric Dating of tephras from Pre-caldera and Caldera-forming stages, Towada volcano, Northeast Japan

    International Nuclear Information System (INIS)

    Towada volcano is an active volcano located in the northern part of the Northeast Japan arc. We carried out fission-track (FT) and AMS radiocarbon (14C) dating of tephras from Towada and Hakkoda volcanoes to establish a detailed eruptive history during the Pre-caldera and Caldera-forming stages of Towada volcano. The obtained FT ages were 0.23 ± 0.05 Ma for Shirobeta tephra (WP), 0.19 ± 0.05 Ma for T-6 tephra, 0.08 ± 0.03 Ma for Zarame 1 tephra (ZP1), and 0.09 ± 0.03 Ma for Okuse Pyroclastic Flow Deposits. Although these FT ages are consistent with stratigraphy, they have large error ranges of several tens of thousands of years. Therefore, further examinations including application of other chronological dating methods are necessary to obtain more precise estimates of the eruptive age of these tephras. The obtained 14C age was 17,730 ± 70 BP for Biscuit 2 tephra (BP2). Based on stratigraphical consistency, this 14C age is appropriate for the eruptive age of BP2. (author)

  17. Correction and validation of 14C chronologies in lake basins, with reference to modern hydrogeological and geochemical systems - examples

    International Nuclear Information System (INIS)

    The primary question before establishing any accurate, confident timescale for palaeo-environmental reconstructions based on lacustrine sediments consists in the definition of the original signature of the TDIC (Total Dissolved Inorganic Carbon) of the lake water from which authigenic compounds are fog ned. This 'carbon' fingerprint of the TDIC may originate from: - The direct exchange with atmospheric CO2; - The admixture of dead dissolved carbon (for example through the leaching of ancient carbonated rocks on the watershed brought to the lake via tributaries) implying the non-equilibrium, and then the ageing, of lake surface waters; - Hydrogeological features of the lake system, such as (i) the connection of the lake waters with extended, shallow aquifers in which the radioactive 14C decay already occurs, or (ii) high hydraulic gradient (mountain landscape) precluding water-rock interaction at the basin scale; - Deep 14C-free CO2 rising along faults in volcanic/tectonic areas, labelled with specific, although wide, ranges of δ 13C values from 0 to -9%o PDB. Previous and on-going works on lakes in key regions have highlighted that, although each lake constitute a specific case study, they can be gathered in groups representing typical cases of distortion of the 14C cycle in lacustrine systems: - eg Lake Bangong (Western Tibet): deep CO2 at the lake bottom, and corrections of the chronology based on the 13C/14C couple and on a regression equation defined on datings... - eg Lake Abiyata (East African Rift): ageing of the authigenic carbonates due to the mixing, at the water/sediment interface, of the lake water and the 14C-depleted regional groundwater; - eg Lake Langano (East African Rift): deep CO2 at the lake bottom and correction of the ageing of the lake surface water by a black-boxes model which provide a step-by-step calculation including the 14C input of atmospheric nuclear weapon tests in the 1960's and the lake turn-over; - eg Lake Aibi (Northern Xinjiang

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

    Science.gov (United States)

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

    2015-10-01

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

  19. Distribution and biodegradability of 14C-residues bound in various soil fractions after treatment of the soil with model 14C-chemicals

    International Nuclear Information System (INIS)

    The long-term fate of 14C-labelled 4-chloroaniline, 2,4,6-trichloroaniline, 2,4,6-trichlorophenol and trichloroethylene in soil was studied under field conditions. As a natural reference compound, 14C-glucose was also studied. Most of the trichloroethylene applied was lost by volatilization and/or degradation during a 25-week period. The soils were exhaustively extracted with methanol and then re-extracted with acetate buffer solutions. The extracted soils were fractionated into humic acid, fulvic acid, humin and inorganic fractions. With the exception of 2,4,6-trichloroaniline the bound residues were more than 31% of the amount of radiocarbon initially applied. Insoluble residues of the natural compound glucose were bound preferentially in the inorganic fraction, whereas 14C of the four xenobiotics was concentrated more in the humic acid fraction, with the portion increasing in the order: glucose 14C in soil is present in a metabolized form. (author)

  20. Reassessment of 14CO2 compartmentation and of [14C]formate oxidation in rat liver

    International Nuclear Information System (INIS)

    Our previous report had concluded that a fraction of [14C]formate oxidation in liver occurs in the mitochondrion. This conclusion was based on the labeling patterns of urea and acetoacetate labeled via 14CO2 generated from [14C]formate and other [14C]substrates. We reassessed our interpretation in experiments conducted in (i) perifused mitochondria and (ii) isolated livers perfused with buffer containing [14C]formate, [14C]gluconolactone, 14CO2, or NaH13CO3, in the absence and presence of acetazolamide, an inhibitor of carbonic anhydrase. Our data show that the cytosolic pools of bicarbonate and CO2 are not in isotopic equilibrium when 14CO2 is generated in the cytosol or is supplied as NaH14CO3. We retract our earlier suggestion of a mitochondrial site of [14C]formate oxidation

  1. Alternatives to reduce 14C emissions in the reprocessing of HTR fuel elements

    International Nuclear Information System (INIS)

    The interest of the public and of experts has increasingly focused on the formation of 14C in nuclear reactors and its release from reactors and reprocessing plants. The paper attempts an experimental check of the validity of theoretical estimations concerning 14C production rates. In particular, the applicability of the 14C analysis in irradiated LWR pellets is checked and transferred to HTR fuel concepts. Statements on the 14C content in matrix graphite, coating, and fuel make it possible to determine those process steps in which 14C release is highest. Possibilities to reduce 14C emissions by improved fuel element production technologies and by mechanical separation of graphite before combustion are theoretically estimated. (orig./GL)

  2. {sup 14}C emission from Swedish nuclear power plants and its effect on the {sup 14}C levels in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Stenstroem, K.; Erlandsson, Bengt; Hellborg, R.; Kiisk, M.; Persson, Per [Lund Univ. (Sweden). Dept. of Nuclear Physics; Mattsson, Soeren; Thornberg, C. [Lund Univ., Malmoe (Sweden). Dept. of Radiation Physics; Skog, G. [Lund Univ. (Sweden). Dept. of Quaternary Geology

    2000-02-15

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

  3. {8-14C}-Adenine and {1-14C}-isopentenyl pyrophosphate - precursors for root-produced cytokinins in the tomato (Lycopersicon esculentum mill.)

    International Nuclear Information System (INIS)

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

  4. Why date old bones?

    International Nuclear Information System (INIS)

    The methods for pretreatment and purification of bone have not been accorded the same standard protocols that are applied to other sample materials. Many users lack confidence in bone dates, with some justification, and it is not clear how to proceed. With the advent of AMS dating, it is becoming easy to date very small amounts of highly purified samples such as single amino acids from bone collagen. This note serves a warning that there are dangers in the uncritical application of powerful separation and measurement techniques to uncharacterized material. (orig.)

  5. Dissipation and leaching of 14C-monocrotophos in soil columns

    International Nuclear Information System (INIS)

    Dissipation and leaching of 14C-monocrotophos was studied in the field. Two sets of PVC cylinders were used - one set received only 14C monocrotophos and the other received 14C-monocrotophos along with dimethoate, deltamethrin, endosulfan, cypermethrin and 1.06 mg unlabelled monocrotophos. Both setups showed a similar pattern of dissipation with a half-life of 277.2 days. Leaching of monocrotophos was observed into the 30cm soil layer. (author)

  6. An enzymic method for the determination of [1-14C] lactose

    International Nuclear Information System (INIS)

    A simple, rapid and specific method for the determination of [1-14C] lactose in biological fluids is described. It is based on the enzymic removal of the 1-14C atom of lactose as [14C] carbon dioxide, using commercially available enzymes. The assay involves only one critical addition and the entire reaction can be carried out in a scintillation vial. (author)

  7. Effect of high temperature stress on photosynthesis and partitioning of 14C in Indian mustard

    International Nuclear Information System (INIS)

    The influence of high temperature stress on 14Co2 assimilation and partitioning of 14C by photosynthetically active parts of Indian mustard is investigated. It is observed that heat stressed plants have low rates of 14Co2 assimilation which leads to low rates of 14C export from source organs. Heat stress is also found to inhibit translocation of 14C-assimilates into sink organs. (M.G.B.). 21 refs., 4 figs

  8. Bound residues of 14C-chlorfenvinphos in winter rape and soil

    International Nuclear Information System (INIS)

    The binding properties of chlorfenvinphos were studied by application of 14C-chlorfenvinphos to the leaves and stems of winter rape and two loamy sand soils of different organic matter content. After application of vinyl-14C-chlorfenvinphos to the plants at a dosage of 0.3 mg/plant, no bound radioactivity was detected either in the flowers and siliques or in the roots. In the leaves and/or stems, the bound 14C-residues, expressed as chlorfenvinphos, ranged from 0.02 μg/g one hour after the treatment to 0.18 μg/g at harvest. Repeated treatment applied to the plants 9 days after the first application caused no increase of the bound residue concentration. Various treatments of stem-bound 14C with alkali and acid led to release of some radioactivity. When vinyl-14C-chlorfenvinphos was applied to the soils, the bound 14C-residues increased and the extractable 14C-residues decreased with time, particularly in the soil of higher organic matter content. After 114 days, the bound 14C-residues, expressed as percentage of the applied 14C, amounted to 13.7% in the soil of higher and 11.2% in the soil of lower organic matter content. When soil was treated with ring-14C-chlorfenvinphos, the bound and extractable 14C-residues were somewhat higher than those determined for vinyl label. Experiments suggested that binding was related to the activity of soil microorganisms since soil sterilization resulted in a reduction of bound 14C-residues by 80% (vinyl label) and 79% (ring label). (author)

  9. Chemical and biological evolution of (U-14C)phenol sorbed on activated carbon

    International Nuclear Information System (INIS)

    Methods describing the chemical and biological evolution of (U-14C)phenol adsorbed on activated carbon are given with or without the use of bacteria. Without bacteria, the (U-14C)phenol initially adsorbed is not removed from the carbon after adding a solution of unlabelled phenol through the column for eight days. With bacteria, the (U-14C)phenol initially present, is removed (60-70%) from activated carbon with a solution containing unlabelled phenol, nitrogen and phosphorus. (author)

  10. Fate of 14C-labeled microbial products derived from nitrifying bacteria in autotrophic nitrifying biofilms

    OpenAIRE

    Okabe, Satoshi; Kindaichi, Tomonori; Ito, Tsukasa

    2005-01-01

    The cross-feeding of microbial products derived from 14C-labeled nitrifying bacteria to heterotrophic bacteria coexisting in an autotrophic nitrifying biofilm was quantitatively analyzed by using microautoradiography combined with fluorescence in situ hybridization (MAR-FISH). After only nitrifying bacteria were labeled with [14C] bicarbonate, biofilm samples were incubated with and without NH4+ as a sole energy source for 10 days. The transfer of 14C originally incorporated into nitrifying b...

  11. Facile preparation of a 4-substituted [2,6-14C]pyridine: synthesis of [14C]SK and F 105809

    International Nuclear Information System (INIS)

    [14C]Formaldehyde was used in a nucleophile-assisted iminium ion cyclization with N-benzyl-3-butynylamine to provide N-benzyl-4-iodo-1,2,5,6-tetrahydro [2,6-14C2]pyridine. Palladium-catalyzed coupling of this vinyl iodide with the organozinc derivative 2 gave the corresponding 4-arylated tetrahydropyridine. Treatment of this compound at elevated temperatures with Pd/Al2O3 in nitrobenzene solution caused hydrogenolysis of the benzyl group and aromization, generating the 4-substituted [2,6-14C2]pyridine 4 in good overall radiochemical yield from [14C]formaldehyde. In high yields, compound 4 was converted via the methylsulfide [14C]SK and F 105561 (1b) to the methylsulfinyl compound [14C]SK and F 105809 (1a). It is proposed that, during the iminium ion cyclization, randomization of label between the 2- and 6-positions of the tetrahydropyridine ring occurs as the result of rapid equilibration between alkynyl and allenyl iminium ions, prior to cyclization. (author)

  12. Synthesis of labeled 5-hydroxy-6-methyl(4,6-14C)uracil

    International Nuclear Information System (INIS)

    β-Uramino(1,3-14C)crotonic ester is prepared for the first time by condensation of urea with labeled (2,4-14C)acetoacetic ester in the presence of ethanol and concentrated HCl. Treatment of β-uramino(1,3-14C)crotonic ester with base gives the Na salt of β-uramino(1,3-14C)crotonic acid. Hydrolysis of the above acid by HCl at 65 degrees gives 6-methyl(4,6-14C)uracil. The oxidation of 6-methyl(4,6-14C)uracil by solid ammonium persulfate in basic solution at 40-70 degrees C gives the intermediate 6-methyl(4,6-14C)uracil-5-ammonium sulfate in 35% yield with 99-100% purity. Hydrolysis of pure 6-methyl(4,6-14C)uracil-5-ammonium sulfate by H2SO4 at 85-95 degrees C gives 5-hydroxy-6-methyl(4,6-14C)uracil in 95-100% yield with 99-100% purity. The product purity is proved by TLC, melting point, elemental analysis, and IR, UV, and PMR spectra

  13. Stimulus-dependent labeling of cultured ganglionic cell with [14C]2-deoxyglucose

    International Nuclear Information System (INIS)

    The authors prepared cultures of dissociated cells from the ciliary (CG) and dorsal root ganglion (DRG) of 10-12-day-old chick embryos, and applied [14C]2-deoxyglucose ([14C]2-DG) to the cultured cells to examine the effects of stimulation on the labeling with [14C]2-DG at the single cell level. Electrical current stimulation increased [14C]2-DG uptake in CG and DRG neurons. The increase depended on frequency of the stimulation. These effects were potentiated by the application of tetraethylammonium, but suppressed by tetrodotoxin. Externally applied potassium ions increased the [14C]2-DG uptake in the CG cell, depending logarithmically on the concentration of applied KCl. The concentration-dependent increase agreed with potassium effect on the equilibrium potential. For CG cells, acetylcholine (ACh), glutamate, γ-aminobutyric acid (GABA) and glycine induced remarkable increases of the [14C]2-DG uptake, while dopamine did not induce any change. For DRG cells, GABA and glycine facilitated the [14C]2-DG uptake, while ACh, glutamate and dopamine did not have any significant effects on it. These facilitatory actions of neurotransmitters on the [14C]2-DG uptake are mostly consistent with the excitatory effects of the substrates on both CG and DRG cells in culture. The results suggest that the [14C]2-DG uptake in single cells is intimately correlated with action potential generation and change in the resting potential. (Auth.)

  14. Synthesis of carbonyl-/sup 14/C labelled 'acetochlor'

    Energy Technology Data Exchange (ETDEWEB)

    Jablonkai, I.; Marton, A.F.; Dutka, F. (Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics)

    1982-09-20

    Carbonyl-/sup 14/C labelled 'acetochlor' (2-chloro-N-ethoxymethyl-N-(2-ethyl-6-methylphenyl)acetamide) was prepared by chlorination of acetic-1-/sup 14/C acid obtained from barium radiocarbonate to monochloroacetic-1-/sup 14/C acid which was further chlorinated to monochloroacetyl-1-/sup 14/C chloride. The addition reaction of this latter with 2-ethyl-6-methylene aniline gave a chloromethyl derivative the ethanolysis of which resulted in 'acetochlor' labelled in its carbonyl carbon. The overall radiochemical yield is 51%.

  15. Photorespiratory CO2 release from l-[U-14C]serine in tomato leaves

    International Nuclear Information System (INIS)

    14CO2 release from L-[U-14C]serine in the illuminated tomato leaf was investigated. Exogenously added [1-14C] and [2-14C]glycine were metabolized in the glycolate pathway and 14CO2 was evolved at a low CO2 concentration from [2-14C]glycine in a similar manner to that from L-[U-14C]serine (Yamauchi and Yamada, Soil Sci. Plant Nutr., 26, 191-204 (1980)). α-Hydroxy-2-pyridinemethanesulfonic acid and isonicotinic acid hydrazide increased the [14C]glycolate and [14C]glycine accumulations, respectively, in leaves fed L-[U-14C]serine at a low CO2 concentration with a corresponding decrease in 14CO2 evolution. This may indicate that the carbon of serine was recycled back into the Calvin cycle and then incorporated into the glycolate pathway. The 14CO2 release from L-[U-14C] serine increased at high light intensity and high temperature. The contribution of CO2 release from serine to photorespiration is discussed. (author)

  16. Straw 14C Decomposition and Distribution in Humus Fractions as Influenced by Soil Moisture Regimes

    Institute of Scientific and Technical Information of China (English)

    WANGZHIMING; ZHUPEILI; 等

    1999-01-01

    14C-tracer technique and closed incubation method were used to study straw 14C decomposition and distribution in different fractions of newly fromed humus under different moisture regimes.Decomposition of straw 14C was faster during the initial days,and slower thereafter,Decay rate constants of straw 14C varied from 3.29×10-3d-1 to 7.06×10-3 d-1,After 112d incubation,the amount of straw 14C mineralized was 1.17-1.46 times greater in submerged soils than in upland soils.Of the soil residual 14C,9.08%-15.75% was present in humic acid(HA) and 31.01%-37.62% in fulvic acid(FA).Submerged condition favored the formation of HA,and HA/FA ratio of newly formed humus(labelled)was greater in submerged soils than in upland soils.Clay minerals affected the distribution of straw 14C in different humus fractions.Proportion of 14C present in HA to 14C remaining in soil was greater in Vertisol than in Ultisol.

  17. In situ produced 14C by cosmic ray muons in ablating Antarctic ice

    OpenAIRE

    Kemp, W.J.M. van der; Alderliesten, C.; Borg, K; Jong, A.F.M. de; Lamers, R. A. N.; Oerlemans, J.; Thomassen, M; van de Wal, R. S. W.

    2002-01-01

    Samples of a core (52 m) of ablating Antarctic ice were analysed for 14CO and 14CO2 by accelerator mass spectrometry. The data were compared with a 14C in situ production model that includes muon capture in addition to oxygen spallation by neutrons. The analysis reveals significant in situ14C at depths below 10 m, which we attribute to 14C production by cosmic ray muons. The age of the ice was determined as 9.3±0.4 14C ka BP.DOI: 10.1034/j.1600-0889.2002.00274.x

  18. In situ produced 14C by cosmic ray muons in ablating Antarctic ice

    International Nuclear Information System (INIS)

    Samples of a core (52 m) of ablating Antarctic ice were analyzed for 14CO and 14CO2 by accelerator mass spectrometry. The data were compared with a 14C in situ production model that includes muon capture in addition to oxygen spallation by neutrons. The analysis reveals significant in situ 14C at depths below 10 m, which we attribute to 14C production by cosmic ray muons. The age of the ice was determined as 9.3 ± 0.4 14C ka BP

  19. Proceedings of the second JAEA tandetron AMS utilization workshop

    International Nuclear Information System (INIS)

    Accelerator Mass Spectrometer (AMS) can determine ultra low level long-lived radioactive isotopes in high sensitivity and precision. Tandetron AMS, originally introduced at Mutsu Establishment, the former Japan Atomic Energy Research Institute (JAERI), had been adjusted for the measurement of 14C and 129I. The AMS has mainly been used for marine research around the Japan Sea. This AMS has adopted the open door policy for the general users from the spring of 2006. Recently varieties of research activities using this AMS have been in progress by many users. This workshop aimed to not only exchange information on the AMS and its utilization but also continue stable operation of the AMS. Second JAEA Tandetron AMS Utilization Workshop was held at Mutsu office, JAEA in November 12-13, 2009. In the workshop 70 participants attended. The topic of the conference was about the recent 14C measurement and its application, 129I measurement and its application, and the current state of the use of AMS. This report contains 28 papers presented at the workshop. The 28 of the presented papers are indexed individually. (J.P.N.)

  20. Comparison of δ13C and 14C activities of CO2 samples combusted in closed-tube and elemental-analyzer systems

    International Nuclear Information System (INIS)

    For combustion of organic samples, a closed tube-combustion (CTC) method is generally used, but this method requires much time and labor. The AMS facility at the Center for Chronological Research, Nagoya University, has established a CO2 production and purification system using an elemental analyzer (EA) connected to cryogenic traps. This system enables faster combustion and CO2 purification of samples than does the conventional CTC method. We compared measured carbon yields, δ13C values and 14C activities between EA and CTC samples of carbon standards of various sample quantities. This newly developed EA system had low background 14C activity due to sample preparation; the background activity was similar to that observed for the CTC method. The EA system also showed high precision and accuracy for δ13C and 14C measurements. The EA sample data obtained from conventional quantities (>1 mg carbon) of standards showed good agreement with the results obtained by the CTC method and with the consensus values, though background contamination was detected for samples containing 13C and 14C activity, suggesting that the CO2 produced by combustion might have been prone to adsorption to an inner wall of the combustion tube, to CuO or to both, and that the CO2 produced in the CTC method might have decomposed.

  1. Localized defoliation stress and the movement of 14C-photoassimilates between tillers of Carex bigelowii

    International Nuclear Information System (INIS)

    14C was used to study how localized defoliation affects the pattern and the degree of photoassimilate translocation between interconnected, and physiologically integrated tiller generations of the rhizomatous sedge Carex bigelowii, and important forage species in Icelandic rangelands. The duration of increased 14C subsidy to repetedly defoliated tillers was also studied. 14C-translocation from a labelled tiller to a daughter tiller in control plants was fastest during the first day after labelling, when most of the 14C was translocated. When daughter tillers were defoliated, the amount of 14C translocated into them from labelled parent tillers was increased six-fold and the rate of translocation was still high 4 d after labelling. The greatest amounts of 14C were recovered in green leaves and rhizomes of daughter tillers, but the highest concentration was found in roots. In control plants, the amount of 14C-subsidy to young tillers was inversely related to their size, larger tillers tending to be more photosynthetically independent. However, when the young tillers were defoliated, the 14C-subsidy increased to all size classes. About 20% of the total 14C recovered 10 d after labelling had been exported from the labelled control tillers and translocated both distally into younger tiller generations and proximally into much older tiller generations with only below-ground organs remaining alive. Undefoliated tillers increased their 14C-support to defoliated neighbours (daughter or parent tiller) by increasing the proportion of 14C exported and without changing this basic pattern of direction of 14C-translocation. A defoliated tiller could not increase its subsidy of 14C to its defoliated daughter tiller. When young tillers were defoliated repeatedly, at 10-12 d intervals, their parent tillers subsidized them with increased amounts of 14C after a first and second defoliation, but not after a third defoliation. When the parent tillers were repeatedly defoliated

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

    Directory of Open Access Journals (Sweden)

    L. A. Currie

    2005-01-01

    Full Text Available The primary objective of the research reported here has been the development of a hybrid reference material (RM to serve as a test of accuracy for elemental carbon (EC isotopic (14C speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of 'soot' (EC, the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust, showed a range of results, but since the 'truth' was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC of measurement validity (Currie et al., 2002. Components of the new Hybrid RM (DiesApple, however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically. NIST SRM 2975 (Forklift Diesel Soot has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK and thermal optical transmission (TOT methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS. As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1 both methods exhibited biomass-C 'leakage'; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC isolated contained about 3% of the original biomass-C.; (2 the initial isothermal oxidation stage

  3. Modelling transport of 14C-labelled Natural Organic Matter (NOM) in Boom Clay

    International Nuclear Information System (INIS)

    In Belgium, the Boom Clay formation is considered to be the reference formation for HLW disposal R and D. Assessments to date have shown that the host clay layer is a very efficient barrier for the containment of the disposed radionuclides. Due to absence of significant water movement), diffusion - the dominant transport mechanism, combined with generally high retardation of radionuclides, leads to extremely slow radionuclide migration. However, trivalent lanthanides and actinides form easily complexes with the fulvic and humic acids which occur in Boom Clay and in its interstitial water. Colloidal transport may possibly result in enhanced radionuclide mobility, therefore the mechanisms of colloidal transport must be better understood. Numerical modeling of colloidal facilitated radionuclide transport is regarded an important means for evaluating its importance for long-term safety. The paper presents results from modeling experimental data obtained in the framework of the EC TRANCOM-II project, and addresses the migration behavior of relevant radionuclides in a reducing clay environment, with special emphasis on the role of the Natural Organic Matter (NOM)[1]. Percolation type experiments, using stable 14C-labelled NOM, have been interpreted by means of the numerical code HYDRUS-1D[2]. Tracer solution collected at regular intervals was used for inverse modeling with the HYDRUS-1D numerical code to identify the most likely migration processes and the associated parameters. Typical colloid transport submodels tested included kinetically controlled attachment/detachment and kinetically controlled straining and liberation. (authors)

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

    International Nuclear Information System (INIS)

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

  5. Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

    International Nuclear Information System (INIS)

    Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 (14C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). 14C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA 14C content relative to a well-established 14C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with the BrdU/IdU turnover data, beta-cell DNA 14C content indicated the cells 'birth date' occurred within the subject's first 30 years of life. Under typical circumstances, adult human beta-cells and their cellular precursors are established by young adulthood.

  6. Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

    Energy Technology Data Exchange (ETDEWEB)

    Perl, S; Kushner, J A; Buchholz, B A; Meeker, A K; Stein, G M; Hsieh, M; Kirby, M; Pechhold, S; Liu, E H; Harlan, D M; Tisdale, J F

    2010-03-15

    Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 ({sup 14}C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). {sup 14}C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA {sup 14}C content relative to a well-established {sup 14}C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with the BrdU/IdU turnover data, beta-cell DNA {sup 14}C content indicated the cells 'birth date' occurred within the subject's first 30 years of life. Under typical circumstances, adult human beta-cells and their cellular precursors are established by young adulthood.

  7. Systemic translocation and metabolism of 14C-metalaxyl in citrus

    International Nuclear Information System (INIS)

    Systemic uptake and translocation of 14C-metalaxyl to citrus seedlings from soils (Humic Gley and Yellow Red Latosol) with different physical - chemical properties are studied. Seedlings of Citrus limonia are treated with 14C-metalaxyl. (M.A.C.)

  8. Analysis of 14C contribution to the dose commitment from nuclear power plants

    International Nuclear Information System (INIS)

    Dose commitment 14C released from an operating PWR plant to the environment was re-evaluated. The GASDOS code, a Korean version of GASPAR II code developed by the USNRC, was used for the assessment with the revised dose factors given in the recent ICRP 72. With an arbitrary selection of the Kori site, the nominal release rate, 370 GBq a year for 14C, was assumed. The results shows that contributions of 14C to the total doses at the mid-point of plant life are as much as 87% within the near-field of 80 km radius and 94% over the far-field beyond. The average dose commitment due to one year of operation evaluated for infinite time interval by integration of the annual doses reaches 2.2 man-Sv even when the isotopic dilution of 14C in the biosphere due to fossil fuel burning is considered. In spite of the significant dose commitment incurred by 14C, it is difficult to find a reasonable solution to mitigate the radiological consequences. Reduction of production rate of 14C is hardly expected because the assumed source term originates from the interaction of the reactor coolant water. Removal of 14C from the reactor coolant gives rise to a waste disposal problem, which calls difficulties due to the extraordinarily long half-life of 14C. And a deep-sea disposal scheme is proposed uniquely for this particularly long-lived radioisotope

  9. The synthesis of [methylenedioxy-[sup 14]C]paroxetine BRL 29060A

    Energy Technology Data Exchange (ETDEWEB)

    Lawrie, K.W.M.; Rustidge, D.C. (SmithKline Beecham Pharmaceuticals Research and Development, Harlow (United Kingdom))

    1993-01-01

    Paroxetine (1), BRL 29060A, a potent antidepressant, has been prepared radiolabelled with carbon-14 in the methylenedioxy group in 5 steps and 20.9% overall yield from [[sup 14]C]dibromomethane. Two alternative preparations of 3,4-[methylenedioxy-[sup 14]C]phenol are also described. (Author).

  10. Study on the degradation of 14C maneb during the fabrication of concentrated tomato

    International Nuclear Information System (INIS)

    Tomatoes were contaminated with 14C maneb to know the degradation of this fungicide during the technological process of tomato under laboratory conditions. 57,2% of the initial amount of 14C maneb applied was found in the many metabolites ETM, ETU and EU, were found during the technological transformation of tomato

  11. 14C assimilate distribution and accumulation of hybrid spring wheat during fore-anthesis

    International Nuclear Information System (INIS)

    14C assimilate distribution and accumulation at fore-anthesis in various organs of hybrid spring wheat 901 and its parent Sh an 229 were studied by using 14C tracer techniques. The results showed that from fore-anthesis stage to filling stage, 14C assimilate distribution rate in leaves and sheath decreased by 23.1% and 7.8% respectively for 901, and decreased by 32.1% and 7.7% respectively for Sh an 229. 14C assimilate distribution rate in stems increased by 7.3% and 22.0% for 901 and Sh an 229 respectively. There was a certain accumulation of 14C assimilate at ear shell in both cultivars. From fore-anthesis stage to maturing stage the distribution rate in ear shell raised 12.2% for 901, and 8.7% for Shan 229. 14C assimilate distribution rate in flag leaf in both cultivars gradually reduced within 21 days after anthesis. There was a peak in radioactivity in flag leaf for 901 after 35 days of anthesis. The filling of Shan 229 was faster than that of 901. The radioactivity of 14C assimilate in grain for Shan 229 was higher than that of 901.4.5% of 14C assimilates labelled at fore -anthesis transported to seeds for 901, and 11.1% for Shan 229

  12. Transport and utilization of 14C photosynthate in pigeon pea (Cajanus cajan L.)

    International Nuclear Information System (INIS)

    An investigation was carried out to study the translocation, distribution and utilization of photosynthate from different leaf and branch positions in pigeon pea (Cajanus cajan L.). Among the branches, middle had the higher assimilation of 14C followed by the top and bottom branches in Pant A 3, whereas in Pant A 2, all branches had equal amount of 14C assimilation. Floral leaf (L 8) had higher 14C assimilation than basal leaf (L 2) and main stem leaf of both the varieties. Export of 14C assimilate was highest from top branch followed by middle and bottom branches in Pant A 3. In Pant A 2, bottom branch had higher 14C export than middle and top branch. Most of the 14C assimilate exported from branches as well as leaves was localized in stem during early reproductive phase. Pods and flowers gained relatively low amount of assimilates. During vegetative phase, 68 percent export of assimilate occurred within 24 hr after assimilation. The data of this investigation show that stem of pigeon pea is a great potential sink of 14C assimilate during the early reproductive phase and competes vigorously with developing pods for 14C assimilate during the pod filling stage. The development of varieties which may cease stem growth at the onset of flowering would be useful in increasing the productivity of pigeon pea. (author)

  13. From Pleniglacial to Holocene: a 14C chronostratigraphy of environmental changes in the Konya Plain, Turkey

    Science.gov (United States)

    Fontugne, M.; Kuzucuoǧlu, C.; Karabiyikoǧlu, M.; Hatté, C.; Pastre, J.-F.

    1999-04-01

    In the endoreic, semi-arid Konya basin on the central Anatolian plateaux, long-term hydrological evolution has left various landforms and lacustrine deposits reflecting the regional climatic evolution, as well as human influence on the local environments. This paper presents results from a cooperative programme grouping several institutes from Turkey and France, on lacustrine, marshy and aeolian sediment sequences of Upper Pleistocene and Holocene age. The detailed study of environmental evolution is based on the reconstruction as well as on the characterization of the extension and contraction phases of wetlands occupying the lowest parts of the Konya plain. A soil and a marsh layer are 14C dated ca. 28,000-25,000 yr BP. Three phases of Pleniglacial (from ca. 22,000 to 17,000 yr BP) high lake levels are distinguished. Complementary OSL dates on aeolian dunes confirm the occurrence of two drought periods: the first occurs around the start of the Late Glacial, the second after the Mid-Holocene climatic optimum, the latter being 'in phase' with a similar drought in other Eastern Mediterranean regions. After 17,000 yr BP, no lacustrine phase reached as high a level as the Pleniglacial lake. During the Late Glacial, a shallow freshwater lacustrine phase is identified from >12,500 to 11,000 yr BP. The Late Glacial to Holocene transition corresponds to a general absence of deposits and dateable material, thus suggesting a period of drought, to which no aeolian features have so far been related. The Holocene environmental evolution shows a period of marsh and shallow lake extansion from 6000 to 5500 yr BP; this wetter period is interrupted by the second drought (ca. 5500 yrs BP) as indicated by aeolian dune activity. During the Late Holocene, a renewal of marshes, as well as soil development on slopes, can be interpreted either as climatic changes or as impacts of human use of water and soil resources during prehistoric and historic times.

  14. Degradation and transport of maneb and ethylenethiourea (ETU) in soil. Laboratory and lysimeter experiments with 14C-maneb and 14C-ETU

    International Nuclear Information System (INIS)

    The degradation of 14C-ETU (0.07 mg kg-1) was determined in two coarse sandy soils sampled at Fladerne Baek at 15, 45 and 75 cm's depth. After 50 days of incubation 33%, 20% and 14% of added 14C were evolved as 14CO2 from the soil profile at field 1 and 31%, 6% and 3% from the 3 soil depths form field 3. Differences in degradation in the subsurface may be due to difference in pH, organic carbon content or crop rotation. After 300 days of incubation no residues of ETU could be determined in the soil profile of field 1 whereas field 3 at 45 and 75 cm's depth still contained about 0.73% of added 14C as ETU. Lysimeters with coarse sandy soil (0.5 m2 surface areas and soil depth 110 cm) were grown with potatoes and treated 6 times with 14C-maneb (2 kg a.i./ha) in the summer 1993. During the following 2 years about 0.8% of added 14C was leached out of the lysimeters with about 550 mm of drain water per year. The drain water was analyzed for ethylenethiourea (ETU) and maneb. No maneb was detected and the concentrations of ETU were in all analyzed samples of drain water below 0.1 μg l-1 (limit of quantification). (au)

  15. Studies on dissipation and degradation of 14 C-DDT and 14 C-parathion in egyptian soil under field conditions

    International Nuclear Information System (INIS)

    The rates of dissipation and degradation of the insecticides DDT and parathion were studied under field conditionsm using 14 C-labelled chemicals. Over a period of 12 weeks, extractable, soil-bound and total 14 C-activity were recorded. In case of DDT, dissipation of 14 C-activity from soil showed a continuous and gradual increase reaching about 30% after 8 weeks and remained constant up to 12 weeks. The formation of DDE as a principal metabolite seems to be increasing with time ans accounted for approximately 25% of the extractable residues after 12 weeks. There was also a gradual significant increase in the formation of soil 14 C-bound residues which reached 12% of the total residues after the same period. On the other hand, parathion dissipation from the soil under the same conditions did not exceed 10% up to 12 weeks. The amount of 14 C-bound residues was found to contribute 33% of the applied dose. Analysis of the extractable fraction revealed that parathion was partly degraded by soil microorganisms into p-amino phenol, p-nitrophenol, paraoxon, amino parathion and aminoparaoxon in different percentages depending on the depth of soil. 2 fig.,1 tab

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

    International Nuclear Information System (INIS)

    The purpose of this work is to demonstrate that the 14C-urea breath test (UBT) performed at different times combined with the study of the gastric basal transit, which evaluates the intragastric displacement of a labeled solution under fasting conditions, has the advantage of being representative of the whole stomach surface and constitutes a non-aggressive test for the detection of H. pylori. This test, which has been called MIN 14C UBT, is a modification of the conventional 14C UBT in which low volumes of a solution of 14C-urea together with 99mTc-sulfur colloid are administered. The 99mTc-sulfur colloid is not absorbed in the gastrointestinal tract and has the great advantage of allowing the 'visualization' of the transit of the 14C-urea within the gastrointestinal tract. This modification allows the simultaneous determination of the production of the 14CO2 and the place where this process occurs. The results show that there is a good correlation between the images obtained and the breath samples collected. We found that this test has a sensitivity of 98% and a specificity of 96% for H. pylori detection

  17. Preparation of specifically labeled 14C-(lignin)- and 14C-(cellulose)-lignocelluloses and their decomposition by the microflora of soil

    International Nuclear Information System (INIS)

    Microbial decomposition of lignocellulose in soil was studied using radioisotope techniques. Natural lignocelluloses containing 14C in either their lignin or cellulose (glucan) components were prepared by feeding plants L-[U-14C]phenylalanine or D-[U-14C]glucose, respectively, through their cut stems. Detailed chemical and chromatographic characterization of labeled lignocelluloses from three hardwood and three softwood species showed that those labeled by the [14C]glucose incorporation method contained specifically labeled cellulosic components, whereas those labeled by the [14C]phenylalanine incorporation method contained specifically labeled lignin components. Microbial degradation of these differentially labeled lignocelluloses was followed by monitoring 14CO2 evolution from selected soil samples incubated with known amounts of radiolabeled lignocelluloses. The lignin components of the six woods were shown to be decomposed in soil 4 to 10 times more slowly than their cellulosic components. These rates of mineralization were comparable to the generalized patterns previously reported in the literature. The present technique, however, was thought to be simpler, more sensitive, and less prone to interference than methods previously available

  18. Rapid increase in cosmogenic 14C in AD 775 measured in New Zealand kauri trees indicates short-lived increase in 14C production spanning both hemispheres

    Science.gov (United States)

    Güttler, D.; Adolphi, F.; Beer, J.; Bleicher, N.; Boswijk, G.; Christl, M.; Hogg, A.; Palmer, J.; Vockenhuber, C.; Wacker, L.; Wunder, J.

    2015-02-01

    In 2012, Miyake et al. reported a sudden and strong increase of the atmospheric radiocarbon (14C) content in Japanese cedar trees of 1.2% between AD 774 and 775. While their findings were quickly confirmed by a German oak chronology for the Northern Hemisphere (NH), the question remained if the effect was seen in both hemispheres. Here we present the first annually resolved Southern Hemisphere (SH) 14C record spanning the interval AD 760-787, using New Zealand kauri (Agathis australis) chronology wood. An almost identical distinct increase compared to Northern Hemisphere data was observed, suggesting a cosmic event with globally uniform impact as a potential cause for the increase. Deploying a carbon cycle box model a worldwide averaged net 14C production of 2.2 ×108 14C atoms cm-2 was estimated, which is 3.7 times higher than the average annual 14C production. The immediate appearance of the event in tree rings on both hemispheres suggests a short duration event of significantly less than 1 yr.

  19. A new AMS facility in Mexico

    Science.gov (United States)

    Solís, C.; Chávez-Lomelí, E.; Ortiz, M. E.; Huerta, A.; Andrade, E.; Barrios, E.

    2014-07-01

    A new Accelerator Mass Spectrometry system has been installed at the Institute of Physics of the National Autonomous University of Mexico (UNAM). A sample preparation chemistry laboratory equipped with computer controlled graphitization equipment (AGEIII) has also been established. Together both facilities constitute the LEMA (Laboratorio de Espectrometría de Masas con Aceleradores) first of its kind in Mexico. High sensitivity characterization of the concentration in a sample of 14C as well as 10Be, 26Al, 129I and Pu are now possible. Since the demand for 14C dating is far more abundant, a data analysis program was developed in the cross-platform programming language Python in order to calculate radiocarbon age. Results from installation, acceptance tests and the first results of 14C analyses of reference materials prepared in our own facility are presented.

  20. A new AMS facility in Mexico

    International Nuclear Information System (INIS)

    A new Accelerator Mass Spectrometry system has been installed at the Institute of Physics of the National Autonomous University of Mexico (UNAM). A sample preparation chemistry laboratory equipped with computer controlled graphitization equipment (AGEIII) has also been established. Together both facilities constitute the LEMA (Laboratorio de Espectrometría de Masas con Aceleradores) first of its kind in Mexico. High sensitivity characterization of the concentration in a sample of 14C as well as 10Be, 26Al, 129I and Pu are now possible. Since the demand for 14C dating is far more abundant, a data analysis program was developed in the cross-platform programming language Python in order to calculate radiocarbon age. Results from installation, acceptance tests and the first results of 14C analyses of reference materials prepared in our own facility are presented

  1. A new AMS facility in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Solís, C., E-mail: corina@fisica.unam.mx; Chávez-Lomelí, E.; Ortiz, M.E.; Huerta, A.; Andrade, E.; Barrios, E.

    2014-07-15

    A new Accelerator Mass Spectrometry system has been installed at the Institute of Physics of the National Autonomous University of Mexico (UNAM). A sample preparation chemistry laboratory equipped with computer controlled graphitization equipment (AGEIII) has also been established. Together both facilities constitute the LEMA (Laboratorio de Espectrometría de Masas con Aceleradores) first of its kind in Mexico. High sensitivity characterization of the concentration in a sample of {sup 14}C as well as {sup 10}Be, {sup 26}Al, {sup 129}I and Pu are now possible. Since the demand for {sup 14}C dating is far more abundant, a data analysis program was developed in the cross-platform programming language Python in order to calculate radiocarbon age. Results from installation, acceptance tests and the first results of {sup 14}C analyses of reference materials prepared in our own facility are presented.

  2. Date Rape

    Science.gov (United States)

    ... Can I Help a Friend Who Cuts? Date Rape KidsHealth > For Teens > Date Rape Print A A ... en español Violaciones durante citas What Is Date Rape? When people think of rape , they might picture ...

  3. Bound residues in corn plants treated with 14C-atrazine and bioavailability to rats

    International Nuclear Information System (INIS)

    Corn plants, about 3.5 months old and treated with 14C-atrazine, were used in an experiment in which the aerial portion of the plants was exhaustively extracted with solvents. The extracted dried material containing bound 14C-residues was fed to rats. The extracted aerial portion of control corn plants fortified with 14C-atrazine was also fed to rats. After four days, 88% and 32% of the radioactivity was excreted in the faeces, and 10% and 60% radioactivity was voided in the urine from rats fed plant material containing bound and fortified 14C-residues, respectively. The data suggest that the bioavailability to rats of bound 14C-residues in corn material is low. (author)

  4. Effects of commercial processing procedures on 14C-pirimiphos-methyl residues in soybean oil

    International Nuclear Information System (INIS)

    Soybean plants were treated with two applications of 14C-pirimiphos-methyl under conditions of local agricultural practice. 14C-residues in the harvested seeds averaged 2.25 mg/kg; corresponding to 0.37% of the applied dose. The insecticide residue in crude oil and cake amounted to 1.6 and 1.5 mg/kg, respectively. About 75% of the 14C-activity in the crude oil could be eliminated by simulated commercial processes locally used for oil refining. The refined oil had a residue level of about 0.4 ppm, mainly in the form of pirimiphos-methyl and 2-diethylamino-4-hydroxy-6-methyl pyrimidine. Refining of soybean oil fortified with 14C-pirimiphos-methyl led also to a high loss of 14C-residues (79%). The refined oil contained a residue consisting of pirimiphos-methyl and its phenol. (author). 7 refs, 1 fig., 3 tabs

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

    International Nuclear Information System (INIS)

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

  6. Carbon-14 kinetic isotope effect in the decarbonylation of lactic acid [1-14C

    International Nuclear Information System (INIS)

    The carbon-14 kinetic isotope effect for the decarbonation of lactic acid[1-14C] in sulfuric acid has been measured in the temperature interval of 20-90 deg C. The experimental values of (k12C/k14C) are compared with the theoretical 14C kinetic isotope effect calculated assuming that one carbon-oxygen stretching vibration is lost in the rate-determining step. The discrepancy between experimentally observed temperature dependence of the 14C kinetic isotope effect and the theoretical one is explained by the possible side reactions wich change the apparent degrees of decarbonylation and isotopic composition of CH3CHOHCOOH[1-14C] used in experiments aiming at the determination of carbon-14 kinetic isotope effect in the decarbonylation process itself. (author) 6 refs.; 1 tab

  7. The release of 14C-chlorsulfuron bound residue by autoclavingmethod and its identification

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    When individual microorganisms were used torelease bound pesticide residues, it was ussually not take into fullaccountwhether the autoclaving method could lead to the releaseof bound residues. The soil containing bound14C-chlorsulfuron residues was treated with an autoclavein this study. The results reveal that the bound14C-chlorsulfuron residue can be released from the soilwhen treated with the autoclave and the release rate canbe remarkably enhanced by adding water into the soil whensubjected to such treatment. A TLC analysis showed that thereleased 14C-residue was one of the degraded products of14C-chlorsulfuron. After derivatization and analysis using theGC-MS, the released 14C-residue was tentatively identifiedas 2-amino-4-hydroxyl-6-methyl-1,3,5-triazine.

  8. Polar ice ablation rates measured using in situ cosmogenic 14C

    International Nuclear Information System (INIS)

    Appreciable 14C can be produced in situ in polar ice when 14C was studied in CO2 extracted from both accumulation and ablation samples. In some ablation samples 14C activities were observed to be between four and six times higher than those expected due to trapped atmospheric CO2. Here we report the detection of an unambiguous signal of in situ cosmogenic 14C in ice samples from two ablation sites in the Antarctic. The 14C is produced mainly by nuclear spallations of oxygen in ice. The observed concentration of 14C in ablation ice samples is 1-3 x 103 atom per g ice - three orders of magnitude higher than expected from the amount of trapped atmospheric CO2 in this ice. The in situ 14C has a unique signature: about 60% exists as 14CO and the remainder as 14CO2. This result is consistent with that expected from studies of artificially produced 11C in solid targets. The 14C concentration is found to decrease with depth as expected for in situ production. The calculated model ablation rates are found to be 5.8 ± 0.7 and 7.6 ± 0.8 cm yr-1 at two sites from the Allan Hills main ice field, in agreement with rates determined by the stake method. Our work indicates that the 14C age of accumulation ice based on trapped (atmospheric) CO2 would be an underestimate of the true age, if a correction is not made for in situ produced 14CO2. This can be done easily because the 14C activities of both the CO and CO2 phases, as well as the trapped CO2 concentration, can be measured. (author)

  9. Microscale radiocarbon dating of paintings

    Energy Technology Data Exchange (ETDEWEB)

    Hendriks, Laura; Hajdas, Irka; McIntyre, Cameron [ETH Zurich, Ion Beam Physics, Zurich (Switzerland); Kueffner, Markus; Ferreira, Ester S.B. [SIK-ISEA, Zurich, Zurich (Switzerland); Scherrer, Nadim C. [Bern University of Applied Sciences, HKB, Bern (Switzerland)

    2016-03-15

    In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. {sup 14}C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, provided the opportunity to evaluate the dating accuracy on paintings realized before and after 1950 AD when the {sup 14}C bomb peak was created, as a result of the nuclear tests conducted in the 1950/1960s. The work focused on the one hand on minimizing the size of the canvas sample required for accelerator mass spectrometer radiocarbon measurement on the gas ion source of the MICADAS and, on the other hand, on testing the possibility of dating the organic binder of the paint. Following careful characterization of the paint composition by X-ray fluorescence spectroscopy, Fourier transformed infrared spectroscopy, and Raman spectroscopy, paints containing no other carbon source than the natural organic binder were identified and dated. (orig.)

  10. Importance of the in situ production of 36Cl, 36Ar and 14C in hydrology and hydrogeochemistry

    International Nuclear Information System (INIS)

    The paper critically discusses the conditions for the in situ production of 36Cl, 36Ar and 14C. For several confined aquifers in Australia, Canada and North Africa, the 36Cl content (in atoms/L) close to recharge is about one hundred times greater than can be accounted for by reasonable evapotranspiration values. Possible additional sources of 36Cl include cosmic ray irradiation in the shallow unsaturated zone and solutions of rock chloride in environments where the in situ production of 36Cl is large. Dating of old groundwaters with 36Cl should be limited to cases where chlorinity is constant. The age of Cl-, and hence of groundwater, may then be deduced from the decay of the cosmic 36Cl input, or where the groundwater migrates into a U/Th rich environment, from the subsequent ingrowth of 36Cl because of irradiation by the high in situ neutron flux. In the case of 36Ar, after about 1.5 Ma, the accumulation rate of 36Cl is equal to the 36Cl production rate. In the uppermost few metres of continental crust and of the ocean, cosmic ray interactions enhance production by up to several orders of magnitude. Oceanic production amounts to about one-half of the total production. For Cl- rich fluid inclusions in minerals which remained exposed for a long time close to the surface, values of the 36Ar/40Ar ratio may become much higher than the atmospheric value (3.385x10-3). For 14C, in situ production reactions in both the fluid and the rock matrix and the extent to which they may interfere with the use of 14C for groundwater dating have been assessed. The reactions considered include neutron interactions, the exotic decay of radium and α particle reactions. Groundwater of very low alkalinity in high neutron flux environments (e.g. Stripa granite in central Sweden) may gain in situ produced 14C which is equivalent to a few per cent modern carbon. (author). 57 refs, 4 figs, 3 tabs

  11. Equilibrium partitioning of 14C-benzo(a)pyrene and 14C-benazolin between fractionated phases from an arable topsoil

    International Nuclear Information System (INIS)

    Equilibrium partitioning of hydrophobic 14C-benzo(a)pyrene and hydrophilic 14C-benazolin between fractionated phases from an arable topsoil of Merzenhausen (Germany) was investigated. Topsoil samples were collected from lysimeters which were incubated with different residual crops. A physical soil fractionation based on sedimentation and centrifugation steps was performed after water extraction. Four soil phases were obtained designated sediment (SED) phase (>20 μm), microaggregate (MA) phase (2 μm-20 μm), colloid (COL) phase (14C-benzo(a)pyrene, 14C-benazolin and organic carbon between the soil phases was established. Enrichment factors for the two chemicals and organic carbon are higher in the COL and MA phases than in the SED phase. The distribution constant Kd of chemicals for Merzenhausen topsoil was calculated according to two-phase or three-phase partitioning models. The three-phase partitioning model presumes the contribution of the organic carbon for the binding of chemicals. A log Koc of 5.55 can be calculated in the case of 14C-benzo(a)pyrene, which is typical of the hydrophobic association with the soil organic carbon. In the case of 14C-benazolin, much higher Kd and Koc values were calculated than found with parent molecules after short-time experiments. Long-term aging processes must be considered. Specific effects on the chemical distribution due to the different crop residues were not detected. - The partition coefficient (Kd) of chemicals was calculated according to two-phase or three-phase partitioning models

  12. Appearance of circulating and tissue /sup 14/C-lipids after oral /sup 14/C-tripalmitate administration in the late pregnant rat

    Energy Technology Data Exchange (ETDEWEB)

    Argiles, J.; Herrera, E.

    1989-02-01

    Studies were performed to determine whether and/or how dietary lipids participate in maternal hypertriglyceridemia during late gestation in the rat. After oral administration of glycerol-tri(1-14C)-palmitate, total radioactivity in plasma increased more rapidly in 20-day pregnant rats than in either 19-day pregnant rats or virgin controls. At the peak of plasma radioactivity, four hours after the tracer was administered, most of the plasma label corresponded to 14C-lipids in triglyceride-rich lipoproteins (d less than 1.006), and when expressed per micromol of triglyceride, values were higher in pregnant than in virgin rats. The difference was less after 24 hours, although at this time the level of 14C-lipids in d less than 1.006 lipoproteins was still higher in 20-day pregnant rats than in virgins. Tissue 14C-lipids, as expressed per gram of fresh weight, were similar in pregnant and virgin rats, but the values in mammary glands were much higher in the former group. Estimated recovery of administered radioactivity four hours after tracer in total white adipose tissue, mammary glands, and plasma lipids was higher in pregnant than in virgin rats. No difference was found between 20-day pregnant and virgin rats either in the label retained in the gastrointestinal tract or in that exhaled as 14C-CO2 during the first four hours following oral administration of 14C-tripalmitate. These findings plus the known maternal hyperphagia, indicate that in the rat at late pregnancy triglyceride intestinal absorption is unchanged or even enhanced and that dietary lipids actively contribute to both maternal hypertriglyceridemia and lipid uptake by the mammary gland.

  13. TOCATTA: a dynamic transfer model of 14C from the atmosphere to soil-plant systems

    International Nuclear Information System (INIS)

    Many nuclear facilities release 14C into the environment, mostly as 14CO2, which mixes readily with stable CO2. This complete isotopic mixing (equilibrium) is often used as the basis for dose assessment models. In this paper, a dynamic compartment model (TOCATTA) has been investigated to describe 14C transfer in agricultural systems exposed to atmospheric 14C releases from nuclear facilities under normal operating or accidental conditions. The TOCATTA model belongs to the larger framework of the SYMBIOSE modelling and simulation platform that aims to assess the fate and transport of a wide range of radionuclides in various environmental systems. In this context, the conceptual and mathematical models of TOCATTA have been designed to be relatively simple, minimizing the number of compartments and input parameters required, appropriate to its use in an operational mode. This paper describes in detail 14C transfer in agricultural plants exposed to time-varying concentrations of atmospheric 14C, with a consideration also of the transfer pathways of 14C in soil. The model was tested against in situ data for 14C activity concentration measured over two years on a grass field plot located 2 km downwind of the AREVA NC La Hague nuclear reprocessing plant. The first results showed that the model roughly reproduced the observed month-to-month variability in grass 14C activity, but under-estimated (by about 33%) most of the observed peaks in the 14C activity concentration of grass. This tends to prove that it is not suitable to simulate intra-monthly variability, and a fortiori, the response of vegetation to accidental releases that may occur during the day. The need to increase the temporal resolution of the model has been identified in order to simulate the impact of intermittent 14C releases occurring either the day or night, such as those recorded by the AREVA NC plant. - Highlights: ► We model 14C transfer from the atmosphere to soil-plant systems. ► Model

  14. Effects of fertilizers, fungicides and herbicides on the fate of 14C-parathion and 14C-fonofos in soils and crops

    International Nuclear Information System (INIS)

    The fate of 14C-parathion and 14C-fonofos in soil is significantly affected by the presence of organic and inorganic fertilizers, fungicides and herbicides, possibly via the effect of soil microflora. Soil microorganisms are responsible for the oxidative as well as the reductive degradation of the insecticide. Using 14carbon, the authors studied the effects of selected fungicides (benlate, captafol and manzate) herbicides (2,4-D parathion) and fertilizers ((NH4)6SO4, KNO3, urea) on pesticides in Cromberry soils. Results of the study stress the importance of investigating the environmental fate of a particular pesticide in relation to the presence of the agricultural chemicals

  15. Single-step-synthesis of [1,2-14C]trichloroacetic acid starting from [1,2-14C]potassium acetate

    International Nuclear Information System (INIS)

    Modern trends in investigating tree damages have initiated an actual interest in [14C]trichloroacetic acid with specific activities >3,7 GBq/mmol. Oxidation of representative volatile air pollutants, as the chlorocarbons 1,1,1-trichloroethane and tetrachloroethene, by UV-light leads to trichloroacetic acid. Their biotransformation can be examined only by tracer technique. However, [1,2-14C]trichloroacetic acid (I) of high specific activity is not commercially produced and the described methods for the synthesis of (I) are not feasible in a small scale synthesis (<1 mmol) with a maximum of radioactivity. (orig.)

  16. Preparation of 2-[α-(2-ethoxyphenoxy)benzyl]-[5-14C]morpholine methanesulfonate ([14C]reboxetine):a new antidepressant agent

    International Nuclear Information System (INIS)

    The labelling with radiocarbon of the new antidepressant agent Reboxetine is described. The preparation has been carried out in a two step procedure using 2-chloro-N-(3-(2-ethoxyphenoxy)-2-hydroxy-3-phenyl)propyl-[1-14C]acetamide as starting material. The expected compound was prepared by cyclization of the above halogenoacylamido alcohol to the corresponding morpholone ring followed by reduction to the final [5-14C]morpholine derivative 4, 98% radiochemically pure and with specific radioactivity of 988 MBq/mmol. An overall radiochemical yield of 57.5% was achieved. (author)

  17. Determination of the hydrothermal degradation products of D-(U-14C) glucose and D-(U-14C) fructose by TLC

    International Nuclear Information System (INIS)

    Hydrothermal degradation was examined using D-(U-14C) glucose and D-(U-14C) fructose. By thin layer chromatography with methylene chloride, tetrahydrofuran (THF), acetic acid - 60:20:20 as a mobile phase; it was possible to separate and identify the carbohydrates and their reaction products, glyceraldehyde, dihydroxyacetone, methylglyoxal, glycolaldehyde, 5-hydroxymethylfurfural and furfural. Up to 99% of the initial activity was determined by scintillation counting of the TL-chromatograms. A reaction scheme for the hydrothermal degradation of glucose and fructose was obtained from these results. (author)

  18. Multi-nuclide AMS system at the University of Tsukuba

    International Nuclear Information System (INIS)

    A multi-nuclide AMS system on the 12UD Pelletron tandem accelerator at the University of Tsukuba (Tsukuba AMS system) can measure environmental levels of long-lived radioisotopes of 14C, 26Al, 36Cl and 129I by employing a molecular pilot beam. AMS is an ultrasensitive technique for the study of long-lived radioisotopes, and stable isotopes at very low abundances. The high terminal voltage has an advantage in the detection of heavy radioisotopes. Much progress has been made in the development of new AMS techniques. For example, a standard deviation of the fluctuation for the 36Cl/Cl ratio is ± 2%, and the effective detection limit is better than 1x10-15. In recent years, the main research field of the 12UD Pelletron tandem accelerator has shifted to accelerator mass spectrometry (AMS) research from nuclear physics. This report presents an overview of the Tsukuba AMS system.

  19. 14C SIRI samples at CNA: Measurements at 200 kV and 1000 kV

    Science.gov (United States)

    Santos Arévalo, Francisco-Javier; Gómez Martínez, Isabel; Agulló García, Lidia

    2015-10-01

    The Sixth International Radiocarbon Intercomparison (SIRI) exercise has taken place during late 2013 and 2014. 13 samples were distributed for AMS (Accelerator Mass Spectrometry) and 5 for radiometric laboratories, including one sample exclusively for radiometric laboratories. Being the first opportunity for our laboratory to participate actively in an intercomparison exercise, we have prepared and measured the samples in the two existing AMS dedicated facilities at the Centro Nacional de Aceleradores (CNA): SARA (Spanish Accelerator for Radionuclide Analysis), a 1 MV multielemental AMS system from HVEE, and Micadas, a 200 kV radiocarbon dating system designed by ETH. Results are presented for the two systems, together with a description of both the sample preparation and measurement procedures.

  20. Chemical pretreatments for improving the radiocarbon dates of peats and organic silts in a gley podzol environment : Grahams Terrace, north Westland

    International Nuclear Information System (INIS)

    Radiocarbon dates obtained for peats and organic silts from the high rainfall/leaching environment of North Westland have been shown to conflict with known stratigraphic evidence by yielding anomalously young dates. This study examines the effectiveness of 14 chemical pretreatment methods, including classical humus fractionation of soil organic matter, hydrolysis with mineral acids (6 M HCl and 70% HNO3), and extraction of lipids and cellulose, in removing young carbon contaminants from peat and organic silt samples prior to radiocarbon assay. The criterion chosen for judging the effectiveness of a treatment in removing young contaminants is an increase in 14C age, with the assumption that contamination is largely due to young carbon. Chemical pretreatments were undertaken on peat and organic silt samples taken immediately above (5-0 cm) and below (0-5 cm) a layer of Kawakawa Tephra found at Grahams Terrace in North Westland. Radiocarbon dates, obtained by accelerator mass spectrometer (AMS), showed that most of the pretreatments and their extracts improved the 14C ages compared with untreated samples. The hydrolysis of peat and organic silt samples with 70% HNO3 and dating the resultant residue produced significantly increased 14C dates (c. 6000 years) with respect to untreated samples. The major conclusion from this study is that existing radiocarbon dates of 12,000 yr B.P. and older, on peats and organic silts from gley podzol environments, are contaminated by younger, less stable, more mobile carbon, such as fulvic and humic acid fractions. (author). 20 refs., 1 fig., 1 tab

  1. Proceedings of the international symposium on application of a closed experimental system to modeling of 14C transfer in the environment

    International Nuclear Information System (INIS)

    The Institute for Environmental Sciences (IES) has developed the Closed Ecology Experiment Facilities (CEEF) to achieve advanced technologies for a closed and strictly controlled experiment system, which will bring the life support system in an extremely limited environment into reality. The development of the CEEF has also had another objective to be used for researches on the transfer of gaseous radioactive nuclides released from nuclear facilities. IES, using the CEEF, started researching the site-specific transfer problem of 14C, which is the most effective radionuclide for assessing the exposure dose around a nuclear fuel reprocessing plant. The simplified model and parameters with ample margins, so far, have been used for the assessment of the dose derived from 14C. Realistic dose estimate of 14C with more realistic and site-specific parameters and models is necessary for the safety of the people in the surrounding area and for the public acceptance of nuclear facilities. The CEEF just concluded the initially planned stage of development with the completion of closed circulation experiments for air, water and wastes at the end of 2007. In addition, the beginning of commercial operation of the nuclear fuel reprocessing plant is planned for 2008 and there is increasing public concern on operation safety. Thus, it was a good time to hold a symposium in Rokkasho to discuss recent progress in 14C transfer modeling in the environment and in animal and human bodies, together with relevant experimental technologies. The purpose of the symposium was to exchange up-to-date information on modeling of 14C environmental transfer and relevant technology to realize 14C experiments in a closed system. Through 25 oral presentations, including 2 special lectures, and 7 poster paper presentations in the symposium, exciting information exchanges and intense discussions on present researches were realized, leading to recognition of potential issues for further studies. The 12 of

  2. Evaluation of [methyl- 14C]4'-thio-thymidine for DNA synthesis imaging in vivo

    International Nuclear Information System (INIS)

    Objective: In order to obtain a thymidine analog that might prove simpler to use for imaging DNA synthesis and follow the same biochemistry of thymidine in vivo, we evaluated [methyl- 11C]4'-thio-thymidine ([methyl- 11C]S-dThd) by using the [14C]-labeled counterpart ([methyl- 14C]S-dThd). Methods: [methyl-14C]S-dThd was synthesized by rapid methylation of 5-trimethyl-stannyl-4' -thio-2' -deoxyuridine via a palladium mediated Stille-coupling reaction with [14C]methyl iodide. Degradation of [methyl- 14C]S-dThd when incubated in human blood was analyzed by HPLC. The in vivo potential of [methyl- 14C]S-dThd was evaluated by distribution study of EMT-6 mammary carcinoma-bearing mice. Gemcitabine, a potent inhibitor of DNA synthesis, was used to modulate cell proliferation. Tissue extraction was also performed to investigate the incorporation of [methyl-14C]S-dThd into DNA. Results: [methyl- 14C]S-dThd was obtained in 31-41% radiochemical yield (calculated from [14C]methyl iodide) at 130, 5 min reaction in N,N-dimethylforamide. After semi-preparative HPLC purification, radiochemical purity of [methyl- 14C]S-dThd was >99% and the specific activity was 2.04 GBq/mmol (according to the specific activity of [14C]methyl iodide). Incubation with human blood demonstrated rapid degradation of [2- 14C]thymidine. In contrast, [methyl- 14C]S-dThd was stable with less than 3% degradation at 60 min. In vivo distribution study showed progressive accumulation of radioactivity in proliferating tissues (spleen, thymus, duodenum and tumor). On the other hand, the washout of radioactivity by the non-proliferating tissues (lung, liver, kidney and muscle) appeared nearly exponential. The tumor uptake of [methyl- 14C]S-dThd was high (8.8%ID/g at 60 min) and selective (Tumor to blood ratio: 12.2 at 60 min). Gemicitabine pretreatment significantly reduced the tumor uptake of [methyl- 14C]S-dThd. Relative blood flow as measured by the uptake 4-[N-Methyl- 14C]iodoantipyrine was similar in the

  3. The distribution of Δ14C in Korea from 2010 to 2013

    Science.gov (United States)

    Park, J. H.; Hong, W.; Xu, X.; Park, G.; Sung, K. S.; Sung, Kilho; Lee, Jong-geol; Nakanishi, T.; Park, Hyo-Seok

    2015-10-01

    Δ14C values of leaves of a deciduous tree record to those of atmospheric CO2 within error and were used to map out Δ14C distribution in Korea. We collected ginkgo (Ginkgo biloba Linnaeus, a deciduous tree) leaf samples in mid-June to early July from 2009 to 2013 in Korea to obtain the regional distribution of Δ14C. Commonly CO2 emitted from fossil fuel consumption dilutes atmospheric 14C, while operations and accidents at nuclear power plants can increase it. The distribution maps of Δ14C from 2010 to 2013 in Korea shows that Δ14C values in the northwestern and southeastern parts of Korea are lower than those of the other parts of Korea, which is consistent with the population and industry patterns. Decrease rates of annually averaged Δ14C values in Korea over the study period are larger than those of Pt. Barrow, Alaska, USA (71.3°N, 156.5°W), so the difference between them and those of Pt. Barrow, Alaska, USA became larger annually. This may be due to the increase in fossil fuel consumption in Korea and China. The decrease rate between 2010 and 2011 was smaller than in other years. This could be the effect of the Fukushima power plant accident which occurred in March 11, 2011, but further study is needed to clarify it.

  4. Production of 14C-labeled rhamnolipid of n-alkane mixture

    International Nuclear Information System (INIS)

    This research was carried out to explore the possibility of the use of 14C-glucose by pseudomonas aeruginosa to produce 14C-rhamnolipid and its role in the bioremediation of n-alkanes mixture (n-C10, n-C14). In addition to show whether the bacterial cells can utilize the bio surfactant as a carbon source. The specific activity of 14C-rhamnolipid produced was 0.082 μCi/mmol indicating 1.12% yield of 14C-rhamnolipid from 14C-glucose on the basis of the recovery of radioactivity. Bacterial growth was increased in the growth medium containing 5.6 mmol rhamnolipid of a final specific activity 0,013 μCi/mmol (a mixture of 4.7 mmol non labeled + 0.9 mmol 14C-labeled rhamnolipid), such increase was due to the degradation of n-alkane (nC10, nC12 and n-C14). There was no detection for 14C-rhamnolipid inside the bacterial cells

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    The turnover of 14C-glucose added in 13 soils was studied. The turnover rate of 14C-glucose can be divided into three phases: 0 - 3d, 3 - 28d and 28 - 294d. The range of the turnover rate and half -life of 14C-glucose were 1.3 x 10-1 - 2.5 x 10-1d-1 and 3 - 5d, 0.7x 10-2 - 1.2 x 10-2d-1 and 58 - 97d, 0.5 x 10-3 - 1.4 x 10-3d-1 and 491 - 1504d, respectively. Correlation analysis showed that from 0 to 3 days the turnover rate of 14C-glucose had significant positive correlation with soil qCO2, from 3 to 28 days, the turnover rate of 14C-glucose had no significant correlation with soil physico-chemical and biological properties. The turnover rate of 14C-glucose had significant or highly significant negative correlation with soil total organic carbon, total nitrogen, CEC and significant positive correlation with soil sand content during the period from 28 to 294 days. Turnover of 14C-glucose during the third period has close correlation with soil properties

  7. 14C-photo assimilation, IAA and GA3 contents in Maize treated with aluminum

    International Nuclear Information System (INIS)

    This study was carried out to show the effect of different concentrations of aluminum (0.0, 0.1, 1.0 and 10 m M Al) on the ''14C-photo assimilation and contents of IAA (indole acetic acid) and GA3 (gibberellic acid) in maize plants grown in nutrient solution. Results of 14C-photo assimilation showed that, the highest loss of 14C was in plants treated with 10 m M Al while the lowest loss was in plants treated with 0.1 m M Al throughout the experimental period. 14C in ethanolic extract of plants treated with 1.0 and 10 m M Al was higher than that of control (0.0 Al) while 0.1 m M Al reduced 14C in ethanol extract than the control plants. In contrast to 14C in the ethanol extract, 0.1 m M Al increased 14C-bound in tissue while 1.0 and 10 m M Al decreased it as compared with the control. Al affected both IAA and GA3 contents in the same manner where slight increases were observed due to 0.1 m M and the maximum increase was observed in plants treated with 1.0 m M Al

  8. Fate of [14C]monolinuron in potatoes and soil under outdoor conditions

    International Nuclear Information System (INIS)

    [phenyl-14C]Monolinuron was applied (2.5 and 1.9 kg/ha) to the soil surface of an outdoor lysimeter in two successive years: then, potatoes were grown. Total recovery of 14C in soil, plants, and leached water was about 55% (of 14C applied) after the first growing period and about 43% after the second growing period. Radioactivity in soil contained 77.1% (based on total 14C recovered in soil) bound residues, 15% monolinuron, and the following conversion products: N-(4-hydroxyphenyl)-N'-methoxy-N'-methylurea, N-(4-chlorophenyl)-N'-methylurea. N-(4-chlorophenyl)methylcarbamate, N-(4-chlorophenyl)-N-methyl-methylcarbamate, and 4-chloroformanilide. The leachate contained 0.8% (based on total 14C recovered in leachate) N-(4-hydroxyphenyl)-N'-methoxy-N'-methylurea. Potato plants contained 0.106 mg/kg radioactive residues in peeled tubers after one growing period and 15.94 mg/kg in the tops; after two growing periods, peeled tubers contained 0.091 mg/kg and tops contained 18.87 mg/kg radioactive residues. These residues consisted of bound 14C (57.9% of total 14C recovered in plants), N-(4-hydroxyphenyl)-N'-methoxy-N'-methylurea, N-(4-chlorophenyl)-N'-methylurea, N-(4-chlorophenyl)methylcarbamate, N-(4-chlorophenyl)-N-methyl-methylcarbamate, and 4,4'-dichlorozobenzene

  9. Discussion: Reporting and calibration of post-bomb 14C data

    Energy Technology Data Exchange (ETDEWEB)

    Reimer, P J; Brown, T A; Reimer, R W

    2004-10-11

    The definitive paper by Stuiver and Polach (1977) established the conventions for reporting of {sup 14}C data for chronological and geophysical studies based on the radioactive decay of {sup 14}C in the sample since the year of sample death or formation. Several ways of reporting {sup 14}C activity levels relative to a standard were also established, but no specific instructions were given for reporting nuclear weapons testing (post-bomb) {sup 14}C levels in samples. Because the use of post-bomb {sup 14}C is becoming more prevalent in forensics, biology, and geosciences, a convention needs to be adopted. We advocate the use of fraction modern with a new symbol F{sup 14}C to prevent confusion with the previously used Fm, which may or may not have been fractionation corrected. We also discuss the calibration of post-bomb {sup 14}C samples and the available datasets and compilations, but do not give a recommendation for a particular dataset.

  10. New 14C ages of the Younger Oshima Group, Izu-Oshima volcano, Izu-Ogasawara arc, Japan

    International Nuclear Information System (INIS)

    New accelerator mass spectrometry (AMS) 14C ages from some tephra units of the Younger Oshima Group of Izu-Oshima Volcano were obtained. Age of the caldera forming S2 period are 1780±50 yBP and consistent with recent AMS data obtained by other research. The age of S2 period should be revised to be in around 3rd century, about 200 to 300 years older than the previously accepted age from early 1980's. N4 period also shows about 200 to 100 years older than the previous estimated age. The ages of the other periods, N1, Y6, Y5, Y4 and Y2, are consistent with the previously estimated ages by historical records. Since the age of S2 and N4 periods became older, magma discharge rate during S to N period obtained from the tephra volume was smaller than the old estimate, but still two times higher than the magma discharge rate of Y period. (author)

  11. Evaluation of 14C Behavior Characteristic in Reactor Coolant from Korean PWR NPP's

    International Nuclear Information System (INIS)

    This study has been focused on determining the chemical composition of 14C - in terms of both organic and inorganic 14C contents - in reactor coolant from 3 different PWR's reactor type. The purpose was to evaluate the characteristic of 14C that can serve as a basis for reliable estimation of the environmental release at domestic PWR sites. 14C is the most important nuclide in the inventory, since it contributes one of the main dose contributors in future release scenarios. The reason for this is its high mobility in the environment, biological availability and long half-life (5730 yr). More recent studies - where a more detailed investigation of organic 14C species believed to be formed in the coolant under reducing conditions have been made - show that the organic compounds not only are limited to hydrocarbons and CO. Possible organic compounds formed including formaldehyde, formic acid and acetic acid, etc. Under oxidizing conditions shows the oxidized carbon forms, possibly mainly carbon dioxide and bicarbonate forms. Measurements of organic and inorganic 14C in various water systems were also performed. The 14C inventory in the reactor water was found to be 3.1 GBq/kg in PWR of which less than 10% was in inorganic form. Generally, the activity in the water was divided equally between the gas- and water- phase. Even though organic compound shows that dominant species during the reactor operation, But during the releasing of 14C from the plant stack, chemical forms of 14C shows the different composition due to the operation conditions such as temperature, pH, volume control tank venting and shut down chemistry.

  12. Partitioning of 14C-photosynthate and biomass in relation to senescence characteristics of sorghum

    International Nuclear Information System (INIS)

    The stems remaining after harvest of sorghum (Sorghum bicolor (L.) Moench) grain are a low-cost source of biomass. Semidwarf hybrids exhibiting nonsenescent characteristics may yield more stem biomass than senescent hybrids. This study compared a nonsenescent to a senescent hybrid of semidwarf sorghum using dry wt. and partitioning of 14C-photosynthate and 14C-starch at three stages. A leaf was exposed to 14CO2 or 14C-starch was injected into the middle internode of each hybrid during grain filling and at or after (post) black layer of the grain. Although dry wt. of stem internodes were significantly greater for the nonsenescent compared to the senescent hybrid, 14C-photosynthate partitioning among parts did not differ between hybrids after chase periods of 5 or 7 d. Patterns of 14C-photosynthate partitioning indicated grain, stem internodes, and lateral branches were dominant sinks at grain filling, black layer, and post black layer, respectively. Lateral branch growth comprised all of the biomass increase from black layer to post black layer. At post black layer, 47% of assimilated 14CO2 was partitioned to lateral branches. Both 14C-photosynthate and 14C-starch were remobilized from stem internodes to lateral branches of both hybrids after black layer. Although unmeasured in previous comparisons between nonsenescent and senescent sorghum hybrids, lateral branch growth limited storage of 14C-photosynthate in stem internodes and resulted in similar patterns of 14C-photosynthate partitioning for the two hybrids after black layer in this study

  13. Degradation and leaching behaviour of 14C-glufosinate in a silty sand soil. Experiments in outdoor lysimeters with undisturbed soil cores

    International Nuclear Information System (INIS)

    Degradation and leaching behaviour of 14C-labelled glufosinate in a silty sand soil was investigated in two outdoor lysimeters after repeated application of 12.5 litres/hectare (1/ha) Basta (divided in 7.5 and 5 l/ha respectively). The 14C-loss during application was 4.8-8.2%. The 14C-content in the plants (vines and weeds) was 0.3% of that applied at the most. After 130 days, 25.9 and 25.5% of the applied material was found in the soil up to a depth of 40 cm. One year after the first application, this amount was still 18.5 and 18.6%. As a consequence of the renewed spraying, the detected amounts of 14C were 44.3 and 43.1% some 107 days after the first application in the second experimental year. The additional investigation in lysimeter 2 after 373 days showed a decrease to 33.9%. Most of the detected radioactivity remained in the 0-10 cm soil layer. At the end of the experiment, the amount of 14C in the 30-40 cm layer was 0.5%. The total residues in the 0-10 cm soil layer were less than 1 mg/kg at all dates of sampling, and only a small amount still represented the free acid of the active ingredient. The average values were 0.05 mg/kg after 130 days, 0.01 mg/kg after 363 days and 0.09 mg/kg at the following date of sampling. In the spring of the following year, no residues of the free acid were detectable. The radioactivity in the percolate amounted to a maximum of 0.11% of that applied and in no case represented the free acid of the ammonium salt. (author)

  14. Preparation of 14C-labelled urea for diagnosis of helicobacter pylori infection

    International Nuclear Information System (INIS)

    The preparation of 14C-urea from [14C]-barium carbonate is reported. The results show that chemical yield can reach 80% (average of 6 runs); melt point is 132 - 136 degree C; purity is 99.65% - 99.85%. After being analyzed by IR, UV, NMR, MS, and elemental analysis, the 14C-urea has the same molecular structure as that of standard urea. Animal trial indicates that clinical use is safe. Good stability is shown by stability testing under different luminous flux, temperature and relative humidity

  15. Distribution and effect of 14C-endosulfan in a rice paddy-fish microecosystem

    International Nuclear Information System (INIS)

    The experiment was conducted to evaluate the behaviour of endosulfan in a simulated rice-paddy-fish simulating ecosystem. 14C-endosulfan sprayed directly on rice plant was absorbed more by the shoot than the root and endosulfan sulfate was the major metabolite found at all growth stages. 14C-endosulfan was highly toxic to fish causing 100% mortality from day 1 after spraying to 14 days. The α and β isomers of 14C-endosulfan degraded rapidly into endosulfan sulfate. α-Endosulfan degraded faster than the β -isomer in water and rice plants whereas β -isomer was faster in soil. (author). 5 refs, 2 figs, 7 tabs

  16. Timing is Everything:The Boon and Bane of 14C Geochronology

    Energy Technology Data Exchange (ETDEWEB)

    Guilderson, T; Guilderson, T; Reimer, P J; Brown, T

    2004-10-29

    There are underappreciated limitations of the conversion of {sup 14}C-ages to the fixed, calendrical time-scale that bear directly upon our understanding of the dynamic climate system, or the relationship between the collapse of one civilization and it's neighbor's. In this paper we present a quantitative assessment of the limits of {sup 14}C-geochronology and calibration onto the absolute calendrical time-scale over the Holocene. We take into account not only the inherent limitations of the {sup 14}C-calendar calibration curve, but also analytical uncertainties.

  17. Comparison of (14)C liquid scintillation counting at NIST and NRC Canada.

    Science.gov (United States)

    Bergeron, Denis E; Galea, Raphael; Laureano-Pérez, Lizbeth; Zimmerman, Brian E

    2016-03-01

    An informal bilateral comparison of (14)C liquid scintillation (LS) counting at the National Research Council of Canada (NRC) and the National Institute of Standards and Technology (NIST) has been completed. Two solutions, one containing (14)C-labeled sodium benzoate and one containing (14)C-labeled n-hexadecane, were measured at both laboratories. Despite observed LS cocktail instabilities, the two laboratories achieved accord in their standardizations of both solutions. At the conclusion of the comparison, the beta spectrum used for efficiency calculations was identified as inadequate and the data were reanalyzed with different inputs, improving accord. PMID:26585641

  18. Radio photosynthesis of some 14 C-labelled sugars using the unicellular green alga scenedesmus ACUTUS

    International Nuclear Information System (INIS)

    Radiosynthesis has been carried out using the unicellular green alga scenedesmus acutus together with Na H 14 CO3 solution as a carbon-14 source, in an ordinary photosynthesis chamber. The process is more easier and less laborious than the techniques involving the use of gaseous 14 CO2 in a tight photosynthesis chamber. Uniformly labelled 14 C-glucose, 14 C-fructose and 14 C-sucrose have been prepared with specific activities of several micro curies per milli mole. The specific activity of the products was found to increase on increasing the photosynthesis time or the initial activity of the Na H 14 CO3 solution used. 3 tabs

  19. Studies on bound residues of 14C-malathion in soil

    International Nuclear Information System (INIS)

    The extractability and formation of bound 14C-labelled residues in clay loam soil under laboratory conditions were investigated with malathion. 14C-malathion rapidly decomposed to 14CO2. Twelve days after treatment 56% of the applied dose was lost as 14CO2. Methanol gave the highest extraction efficiency; 6% of the applied radiocarbon was extractable while bound residues amounted to 38%. The soil containing 14C-labelled residues was fractionated into humic acid, fulvic acid and humin fractions. These fractions contained 7.83%, 16.81% and 19.36%, respectively of applied radiocarbon. (author)

  20. Synthesis of the rice herbicide HW-52 [dichlorophenyl ring-14C(U)

    International Nuclear Information System (INIS)

    14C-labeled 2', 3'-dichloro-4-(ethoxymethoxy)benzanilide (HW-52) was synthesized in a total of 9 steps from 1,3-dinitrobenzene [14C(U)]. The key intermediate 2,3-dichloroaniline [14C(U)] was prepared from the starting material by a series of aromatic substitutions and functional group manipulations. Conversion to the final product was achieved in high yield by coupling and further functional group manipulations. The overall radiochemical yield was 1.88% and radiochemical purity of the product was greater than 98.8%. (author)