Structure of 14C via elastic and inelastic neutron scattering from 13C: Measurement, R-matrix analysis, and shell model calculations

International Nuclear Information System (INIS)

Resler, D.A.

1987-03-01

The specific purpose of this work is to provide a better understanding of the 14 C level structure; the general purpose is to provide the details for using shell model calculations in R-matrix analyses. Using the TOF facilities of the Ohio University Accelerator Laboratory, the elastic and first 3 inelastic differential scattering cross sections for 13 C + n were measured at 69 energies for 4.5 ≤ E/sub n/ ≤ 11 MeV. A multiple scattering code was developed which provided a simulation of the experimental scattering process allowing accurate corrections to the small inelastic data. The integrated 13 C(n,α) 10 Be cross section is estimated. The sequential 2n-decay of 14 C states populated by 13 C + n was observed. A shell model code was developed. Normal and nonnormal parity calculations were made for the lithium isotopes using a new two-body interaction. The results for 5 Li predict the 2s/sub 1/2/ and 1d/sub 5/2/ single-particle states to be located below the 3/2 + state. Similar calculations were made for 13 C, 13 N, and 14 C. Results for 13 C and 13 N show for E/sub x/ 7 Li and 14 C, 2 h-barω calculations were done. Shell model calculations generated the R-matrix parameters for the elastic and first 3 inelastic channels of 13 C + n. After adjusting some energies, the predicted structure generally agrees with experiment for E/sub n/ 13 C + n data were refit to replace R 0 background terms by more realistic broad states and to get better agreement with model calculations. R-matrix fitting of the full data set produced new 14 C level information. For E/sub n/ > 4 MeV (E/sub x/ > 12 MeV), 5 states are given definite J/sup π/ assignments; 3, tentative assignments. 122 refs., 91 figs., 30 tabs

The Tritiated Water Skin Barrier Integrity Test: Considerations for Acceptance Criteria with and Without 14C-Octanol.

Science.gov (United States)

Lehman, Paul A; Beatch, Kacie; Raney, Sam G; Franz, Thomas J

2017-01-01

A study was designed to assess barrier integrity simultaneously using separate compounds (probes) for polar and non-polar pathways through the skin, 3 H 2 O and 14 C-octanol, respectively; and to determine whether the two probe approach could better define barrier integrity. A 5-min dose of water containing 3 H 2 O and 14 C -octanol was applied to ex vivo human skin mounted in Franz diffusion cells. The receptor solution was sampled at 30 min, analyzed for 3 H and 14 C content, and the correlation between water and octanol absorption was determined by statistical tests suitable for non-normally distributed data. This study was conducted on skin from 37 donors with from 3 to 30 replicate skin sections per donor (a total of 426 sections). The correlation between 3 H 2 O and 14 C-octanol absorption was low (Pearson correlation coefficient = 0.3485). The 3 H 2 O absorption cutoff used in this study to select for a normal skin barrier rejected some sections in which 14 C-octanol absorption was within normal limits and accepted others in which 14 C-octanol absorption was abnormally high. The converse was true for 3 H 2 O absorption when the 14 C-octanol-based cutoff was used. The results of the 3 H 2 O test or of similar tests that primarily assess the permeability of polar pathways through the skin may not necessarily provide information relevant to the absorption of highly lipophilic compounds. Octanol, or another molecule that more closely matches the physicochemical attributes of the test compound, may characterize properties of the skin barrier that are more relevant to compounds of low water solubility.

14C measurements in aquifers with methane

International Nuclear Information System (INIS)

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

1978-01-01

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

An integrated data-analysis and database system for AMS {sup 14}C

Energy Technology Data Exchange (ETDEWEB)

Kjeldsen, Henrik, E-mail: kjeldsen@phys.au.d [AMS 14C Dating Centre, Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark); Olsen, Jesper [Department of Earth Sciences, Aarhus University, Aarhus (Denmark); Heinemeier, Jan [AMS 14C Dating Centre, Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark)

2010-04-15

AMSdata is the name of a combined database and data-analysis system for AMS {sup 14}C and stable-isotope work that has been developed at Aarhus University. The system (1) contains routines for data analysis of AMS and MS data, (2) allows a flexible and accurate description of sample extraction and pretreatment, also when samples are split into several fractions, and (3) keeps track of all measured, calculated and attributed data. The structure of the database is flexible and allows an unlimited number of measurement and pretreatment procedures. The AMS {sup 14}C data analysis routine is fairly advanced and flexible, and it can be easily optimized for different kinds of measuring processes. Technically, the system is based on a Microsoft SQL server and includes stored SQL procedures for the data analysis. Microsoft Office Access is used for the (graphical) user interface, and in addition Excel, Word and Origin are exploited for input and output of data, e.g. for plotting data during data analysis.

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.

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Sophistication of 14C measurement at JAEA-AMS-MUTSU. Attempt on a small quantity of sample

International Nuclear Information System (INIS)

Tanaka, Takayuki; Kabuto, Shoji; Kinoshita, Naoki; Yamamoto, Nobuo

2010-01-01

In the investigations on substance dynamics using the molecular weight and chemical fractionation, the utilization of 14 C measurement by an accelerator mass spectrometry (AMS) have started. As a result of the fractionation, sample contents required for AMS measurement have been downsized. We expect that this trend toward a small quantity of sample will be steadily accelerated in the future. As 14 C measurement by AMS established at Mutsu office require about 2 mg of sample content at present, our AMS lags behind the others in the trend. We try to downsize the needed sample content for 14 C measurement by our AMS. In this study, we modified the shape of the target-piece in which the sample is packed and which is regularly needed to radiocarbon measurement by our AMS. Moreover, we improved on the apparatus needed to pack the sample. As a result of the improvement, we revealed that it is possible to measure the 14 C using our AMS even by the amount of the sample of about 0.5 mg. (author)

AMS measurement of C-14 concentration in a single-year ring of a 2500-yr-old tree

International Nuclear Information System (INIS)

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

2004-01-01

The 14 C concentration in rings of an old tree that date back approximately 2500 yr has been measured at single-year intervals with a highly accurate liquid scintillation counter (LSC) (0.2%) to investigate the 11-yr periodicity of solar activity. To investigate the applicability of AMS to accurate 14 C measurement, 16 graphite samples produced from the cellulose of a single-year tree ring of a 2500-yr-old cedar were measured with the micro analysis laboratory tandem (MALT) accelerator, at The University of Tokyo, and the results were compared with the 14 C age determined using LSC. The average 14 C age of the single-year tree ring calculated from 16 measurements was 2496 ± 23 yr BP, corresponding to the statistical accuracy of 0.26%. This was consistent with the age of 2514 ± 23 yr BP determined using LSC within the acceptable error range, which indicates that accelerator mass spectrometry (AMS) is applicable for accurate 14 C measurement using multi-graphite for the same single-year tree ring

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

Energy Technology Data Exchange (ETDEWEB)

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

1991-02-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1976-01-01

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

Development of a C-14 detector and measurement of delta C-14 in dated tree rings grown in 1043 to 1055

International Nuclear Information System (INIS)

Oona, H.

1979-01-01

A proportional counter was constructed from plastic scintillator for measuring the C-14 contents in dendrochronologically dated tree ringas. The tree rings were individually converted to methane which, at one atmosphere pressure, was used as the counter gas. The wall, being a scintillator, serves as the 4π anti-coincidence shell for rejection of natural radioactivity in the material housing the proportional counter and penetrating cosmic ray muons. The output of the proportional counter, which is in anti-coincidence with the scintillation is recorded with a pulse height analyzer. After background subtraction, it yields the beta-decay spectrum of C-14 in the methane-filled proportional counter. The count rate obtained from the 5.5 liter effective volume counter for each year's sample is then referenced to a standard traceable to the National Bureau of Standards, and after corrections due to isotopic fracionation are applied, the ΔC-14 for each sample is determined. The fluctuations in the ΔC-14 are inspected, and used as an estimate for the energy content in the γ-ray burst of the Crab Nebula in 1054 A.D. Fluctuations due possibly to solar flares, neutron flux, cosmic ray muons, and sample preparation restrict the energy estimate to an upper limit of less than or equal to 10 50 ergs

Simple measurement of 14C in the environment using a gel suspension method

International Nuclear Information System (INIS)

Wakabayashi, G.; Ohura, H.; Okai, T.; Matoba, M.

1999-01-01

A simple analytical method for environmental 14 C with a low background liquid scintillation counter was developed. A new gelling agent, N-lauroyl-L-glutamic-α,γ-dibutylamide was used, for the liquid scintillation counting of 14 C as CaCO 3 (gel suspension method). Our procedure for sample preparation was much simpler than that of conventional methods and required no special equipment. The samples prepared with the standard sample of CaCO 3 were measured to evaluate the self absorption of the sample, the optimum condition of counting and the detection limit. Our results indicated that the newly developed technique could be efficiently applied for the monitoring of environmental 14 C. (author)

13C and 14C measurements on lake sediments of the Grosser Ploener See

International Nuclear Information System (INIS)

Erlenkeuser, H.; Willkomm, H.

1979-01-01

Radiocarbon age and 13 C content of organic and inorganic carbon fractions were measured for two sediment cores from the Grosser Ploener See (N-Germany), comprising the whole post-glacial. As compared to the age of the pollen stages, the 14 C age of the organic fraction is seen to show a hard-water effect of about 1000 years throughout the sediment column, indicating a constant recent activity of the lake bicarbonate of about 92% of the standard recent activity during the history of the lake. From the age of sediment samples corrected for hard water effect and for 14 C variations of the atmosphere the sedimentation rate is found to increase from 0.4 to 0.8 mm/year in the pre-Christian era to as high as 10 mm/year during the last 7 centuries. In the lower layers of the sediment, the 14 C content of the marl fraction corresponds to that of the organic component, indicating the autochthonous origin of these carbonates. During the last 2 1 /2 millenia, however, its 14 C content is too small by 10 to 30%, probably reflecting an allochthonous admixture. Increasing rate of sedimentation along with the growing accumulation of allochthonous minerals probably reflect the agricultural activity of man. It is associated with an increasing supply of nutrients to the lake particularly since a man-made rise of the water level at A.D. 1256, resulting in an enhanced rate of primary production which could be recognized from the stable carbon isotope ratios of both the sedimentary organic carbon and carbonate fraction. According to these results, the contribution of planktogenic organic matter to the sediments as compared to the supply of plant litter from the litoral zones is steadily increasing during the history of the lake and becomes the dominating part since the lake level risc in the Middle Ages. According to the 13 C/ 12 C-ratios, the carbonates of the sediment appear to have been precipitated preferentially in the litoral zones. (orig./MG) [de

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

International Nuclear Information System (INIS)

Zhang Yiqiang; Zhong Chuangguang; Zhao Xiaokui; Chen Shunhua

2002-01-01

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

Measurements of in situ produced 14C in terrestrial rocks

International Nuclear Information System (INIS)

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

2004-01-01

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

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1979-10-01

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

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

International Nuclear Information System (INIS)

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

1981-01-01

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

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

International Nuclear Information System (INIS)

Ye Qingfu; Sun Jinhe; Qi Wenyuan; Wu Jianmin

2003-01-01

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

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

International Nuclear Information System (INIS)

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

2000-02-01

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

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)

Stenstroem, K.; Erlandsson, B.; Hellborg, R.; Haakansson, K.; Wiebert, A.; Skog, G.

1993-04-01

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.)

Progress in AMS measurement of "1"2"9I and "1"4C at CIAE

International Nuclear Information System (INIS)

Yang Xuran; Dong, K.J.; Shan, J.; He Ming; Xie, L.B.

2013-01-01

Twenty-four years have passed since the AMS was built at China Institute of Atomic Energy (CIAE) in 1989. We have measured "2"3"6U, "1"8"2Hf, "5"9Ni and other elements. Recently, the routine method of measuring the "1"2"9I concentration in air particle samples using AMS have been set up due to it has great advantages to measure long-lived radioisotopes. For the applications, "1"2"9I could be used for monitoring nuclear environment. "1"2"9I was collected in air particle samples after the accident of Fukushima nuclear power plant and measured at the China Institute of Atomic Energy (CIAE) by using AMS, the result show that "1"2"9I derived from FNPP accident had been arrived in Beijing early on March 26th and "1"2"9I concentration had been greatly increased relative to March 20th. On the other hand, a new system to measure "1"4C of AMS will be designed for the application in bio-medical science: urea breath test (UBT). UBT has been carried out widely by using carbon isotope of "1"3C and "1"4C, respectively, in the world. They are two tracers with different measurement methods but applied by the same principle. Optimizing UBT methods with using "1"4C is the priori for the diagnosis of helicobacter pylori in the future. (author)

"1"4C ages and calendar years of Japanese swords measured with accelerator mass spectrometry

International Nuclear Information System (INIS)

Nagata, Kazuhiro; Matsubara, Akihiro; Kokubu, Yoko; Nakamura, Toshio

2016-01-01

Steel of Japanese swords has been produced with Tatara process from iron sand and charcoal. Carbon dissolved in steel was absorbed from wooden charcoal fuel during the production of the steel. From the decay of "1"4C activity in the steel, the "1"4C age of Japanese sword can be determined. The "1"4C ages of 4 Japanese swords were measured with accelerator mass spectrometry and calibrated to calendar years. Each "1"4C age provided plural calendar year periods with definite probabilities, and one of the periods agreed with the production year of each sword that was determined from the sword master's name cut in the grip of his sword after taking the age range of charcoal used for steel production and usage for several generations of the same names of sword masters into account. (author)

Complete fusion of the 12C+12O, 14N+12C and 15N+12C systems

International Nuclear Information System (INIS)

Conjeaud, M.; Gary, S.; Harar, S.; Wieleczko, J.P.

1978-01-01

Cross sections for evaporation residues following the complete fusion of the 12 C+ 12 C, 14 N+ 12 C and 15 N+ 12 C systems have been measured with a E-ΔE counter telescope in a wide range of incident energies. They are fairly well reproduced by evaporation calculations based on the statistical theory. The total fusion excitation function of the 12 C+ 12 C system shows strong structure, which is compared to the predictions of the reaction cross sections derived from coupled channel calculations and to the integrated inelastic cross sections. Critical angular momenta have been obtained from the fusion cross-section data and these values are discussed in the framework of compound nucleus and entrance channel effects. A striking difference is observed between the fusion cross sections of the 14 N+ 12 C and 15 N+ 12 C systems and shows the importance of the valence nucleons of colliding ions in the fusion process. A possible interpretation might be the influence of the yrast line of the compound nuclei. (Auth.)

Improved precision radiocarbon measurements and natural 14C variations around 10.000 cal BP

International Nuclear Information System (INIS)

Goslar, T.

1990-01-01

The subject of present work, natural radiocarbon variations in the past, is one of the most significant methodological questions of radiocarbon chronology. In the first three chapters, the author discusses problems connected with calibration of conventional radiocarbon dates, and consequences of monitoring the 14 C variations for the research of the changes of geomagnetic field, solar activity and global carbon cycle. Dendrochronological dating, which, in connection with 14 C measurements enables us to reconstruct the radiocarbon variations in the past, is also widely described. Fourth chapter concerns the technical problems of detection 14 C β-activity, especially accounting for proportional counters technique. In the next chapter the author describes results of his own dendrochonological research. Sixth chapter comprises frame discussion of the system for improved precision radiocarbon dating, together with short presentation of equipment, its calibration and analysis of errors. The last chapter gives the reconstruction of the pattern of atmospheric 14 C variations in 300-year period around 10.000 cal BP. It was found that in the last 10.000 years similar pattern repeats periodically. In the end, the author discusses the meaning of negative correlation between 14 C variations and changes of annual tree-ring widths in the oak trunk from Lublinek, for searching the connection between solar activity and climate. (author)

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

International Nuclear Information System (INIS)

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

1984-01-01

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

14C concentrations in tree stems, 1

International Nuclear Information System (INIS)

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

1993-01-01

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

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

International Nuclear Information System (INIS)

Yamashita, Tadaaki

1981-01-01

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

Excitation functions of the systems 12C+14C and 13C+12C

International Nuclear Information System (INIS)

Haindl, E.

1975-01-01

The excitation functions of the systems 12 C+ 14 C and 13 C+ 12 C are investigated for different exit channels. The excitation functions measured do not show correlated structures as in the system 12 C+ 12 C. (WL/AK) [de

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.

Elimination of the 12 C and 16 O in the elastic scattering of 14 C by polarized protons

International Nuclear Information System (INIS)

Avila A, O.L.; Ramirez T, J.J.; Murillo O, G.; Fernandez B, M.

1991-04-01

The study of the elastic scattering of 14 C for polarized protons it provides information on the nuclear structure of 15 N. In the Tandem accelerator of the Nuclear Center in collaboration with the University of Notre Dame is carrying out this study to energy between 5.0 and 9.0 MeV in steps of 10 keV. The measures of differential section and vectorial analyzer power are subjected to shift analysis of phase being able to determine the parameters of the excited levels of 15 N that are it angular momentum, parity, level width and elastic width. The details of this experiment are presented in the ACEL-9102 technical report while in this work it was discussed the way in that contributions of 12 C and 16 O are eliminated that are present as impurities in our target of 14 C. At small angles the elastic components of these impurities are shoveled with the elastic of 14 C. In the experiment carried out in the Nuclear Center were take measures of differential section for 6 angles; 35, 45, 55, 65, 145 and 165 using surface barrier detectors. It is observed that it exists shovels at 35, 45, 55 and 65 while at 145 and 165 the 12 C, the 14 C and the 16 O are totally separate. With the purpose of being able to subtract of the elastic of 14 C the proportion of 12 C, it was decided to bombard a target of 12 C leaving the same geometry that had been used to bombard 14 C. With this also carried out the reaction 12 C (p,p) 12 C between 5.0 and 9.0 MeV in steps of 50 keV. Starting from these spectra are the integration (yield) of the elastic of 12 C. (Author)

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

International Nuclear Information System (INIS)

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

1990-01-01

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

How accurate is the 14C method

International Nuclear Information System (INIS)

Nydal, R.

1979-01-01

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

Measurement of 14C time scale of the rings of a tree by accelerator mass spectrometry

International Nuclear Information System (INIS)

Oda, Hirotaka; Furukawa, Michiaki; Yonenobu, Hitoshi; Ikeda, Akiko; Nakamura, Toshio.

1996-01-01

14 C time scale is different from a histrical data in order that it is calculated by assuming that the concentration of 14 C in the sample has not been changed by age. The object of this work is to make clear the errors in measurement of 14 C time scale of the ring of a tree known the tree age. The every year ring of a Hinoki in Kiso, 950 years old, was used as a sample. The most external ring is determined as 1923 years old on the basis of the dendrochronology. The rings after 1120 years were used as the samples. α-cellulose, the most stable component in the structural components of cell of tree, was prepared from each ring. About 8 mg of α-cellulose was reduced to graphite to be measured by the tandem thoron analytic meter. The results obtained showed that 14 C time scale was older than that of the histrical data in the twelfth and thirteenth century, but it was more new than that of the histrical data from the late seventeenth to the middle of eighteenth century. The results were agreement with that of Stuiver and Pearson (1933). (S.Y.)

{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

Elastic and inelastic scattering of π+ and π- from 12C and 14C measured at T/sub π/ = 164 MeV

International Nuclear Information System (INIS)

Harvey, C.J.

1984-01-01

Detailed angular distributions of the differential cross sections for π/sup +/-/ scattering from 12 C and 14 C have been measured from theta/sub LAB/ = 20 0 to 91 0 at T/sub π/ = 164 MeV. The elastic and inelastic cross sections were determined in an experiment performed at the Los Alamos Meson Physics Facility (LAMPF). These are the first 14 C pion cross sections to be measured near the Δ 33 resonance. Many new states have been identified in the 14 C excitation energy spectrum and their spin and parities assigned through the pion data. Three of the states discovered from a trio with the same 4 - stretched-state configuration. Optical model predictions have been made for the 14 C elastic cross sections with both a coordinate-space and momentum-space interpretation. Pauli blocking, NN correlations, and binding effects have been included in the parameter-free momentum-space calculation. The coordinate-space model, on the other hand, used parameters taken from a global fit to other nuclei at the same energy. Optical calculations were also performed for the 12 C data obtained. However, significant differences were observed between the LAMPF-determined 12 C cross sections at this energy (of which a data set in agreement with the cross sections reported here already existed) and corresponding measurements made at the Swiss Institute for Nuclear Research; differences that increased nearly linearly with scattering angle. Discrepancies as large as those found (up to 50%) make it impossible to distinguish between various formulations of the π-nucleus interaction with such data

Direct LSC method for determination of bio-origin by C-14 measurement

International Nuclear Information System (INIS)

Kristof, Romana; Kozar Logar, Jasmina

2017-01-01

The aim of the research was to test the generalized direct liquid scintillation spectrometry (LSC) method for bio-origin determination by measurement of C-14. Examples of diversified items with known and unknown bio-origin were measured by liquid scintillation counting and analyzed by procedures, developed for fuel samples. Bio-origin of fuels, lubricants and monomer resins were successfully determined via direct LSC method after simple sample preparation with acceptable accuracy and trueness despite their diversity in color, viscosity, density or chemical composition. (author)

15C-15F Charge Symmetry and the 14C(n,γ)15C Reaction Puzzle

International Nuclear Information System (INIS)

Timofeyuk, N.K.; Thompson, I.J.; Baye, D.; Descouvemont, P.; Kamouni, R.

2006-01-01

The low-energy reaction 14 C(n,γ) 15 C provides a rare opportunity to test indirect methods for the determination of neutron capture cross sections by radioactive isotopes versus direct measurements. It is also important for various astrophysical scenarios. Currently, puzzling disagreements exist between the 14 C(n,γ) 15 C cross sections measured directly, determined indirectly, and calculated theoretically. To solve this puzzle, we offer a strong test based on a novel idea that the amplitudes for the virtual 15 C→ 14 C+n and the real 15 F→ 14 O+p decays are related. Our study of this relation, performed in a microscopic model, shows that existing direct and some indirect measurements strongly contradict charge symmetry in the 15 C and 15 F mirror pair. This brings into question the experimental determinations of the astrophysically important (n,γ) cross sections for short-lived radioactive targets

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

International Nuclear Information System (INIS)

Burgos, A.; Ellames, G.J.

1995-01-01

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

Critical study of absorption tests based on the measurement of breath 14CO2 after administration of 14C-labelled fats

International Nuclear Information System (INIS)

Grenier, J.F.; Dauchel, J.; Eloy, M.R.; Mendel, C.; Privat, J.P.

1976-01-01

Oral administration of 14 C-labelled triolein is a useful technique for studying absorption of fats if faecal excretion of the label is observed. However, the difficulties of complete collection and reliable assay of faeces discourage use of this technique, and suggestions have been made that quantitation of absorption by assay of 14 CO 2 exhalation rate might be simpler and adequately reliable. We have compared in 25 subjects the exhalation of 14 CO 2 with the blood activity levels and with the faecal excretion of unabsorbed fat. Our results indicate that the exhalation rate of 14 CO 2 is so poorly correlated with the other indices of absorption that the amount of 14 CO 2 exhaled is not a useful measure of 14 C-triolein absorption. This fact is presumably explained by the variability in the rate of metabolism of absorbed fat, a process that intervenes between absorption and exhalation. (author)

14C levels in Trombay environment

International Nuclear Information System (INIS)

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

1994-01-01

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

Accelerator mass spectrometry analysis of "1"4C-oxaliplatin concentrations in biological samples and "1"4C contents in biological samples and antineoplastic agents

International Nuclear Information System (INIS)

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

2015-01-01

Accelerator mass spectrometry (AMS) is expected to play an important role in microdose trials. In this study, we measured the "1"4C concentration in "1"4C-oxaliplatin-spiked serum, urine and supernatant of fecal homogenate samples in our Yamagata University (YU) – AMS system. The calibration curves of "1"4C concentration in serum, urine and supernatant of fecal homogenate were linear (the correlation coefficients were ⩾0.9893), and the precision and accuracy was within the acceptance criteria. To examine a "1"4C content of water in three vacuum blood collection tubes and a syringe were measured. "1"4C was not detected from water in these devices. The mean "1"4C content in urine samples of 6 healthy Japanese volunteers was 0.144 dpm/mL, and the intra-day fluctuation of "1"4C content in urine from a volunteer was little. The antineoplastic agents are administered to the patients in combination. Then, "1"4C contents of the antineoplastic agents were quantitated. "1"4C contents were different among 10 antineoplastic agents; "1"4C contents of paclitaxel injection and docetaxel hydrate injection were higher than those of the other injections. These results indicate that our quantitation method using YU-AMS system is suited for microdosing studies and that measurement of baseline and co-administered drugs might be necessary for the studies in low concentrations.

Accelerator mass spectrometry analysis of {sup 14}C-oxaliplatin concentrations in biological samples and {sup 14}C contents in biological samples and antineoplastic agents

Energy Technology Data Exchange (ETDEWEB)

Toyoguchi, Teiko, E-mail: tteiko@med.id.yamagata-u.ac.jp [Department of Pharmacy, Yamagata University Hospital, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585 (Japan); Kobayashi, Takeshi; Konno, Noboru; Shiraishi, Tadashi [Department of Pharmacy, Yamagata University Hospital, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585 (Japan); Kato, Kazuhiro; Tokanai, Fuyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata-shi, Yamagata 990-8560 (Japan)

2015-10-15

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

Present status and prospects of ultralow level radioactivity measurements (5). Measurement of time variations of cosmic rays in the past by the detection of ultralow level 14C and 7Be radioactivity

International Nuclear Information System (INIS)

Sakurai, Hirohisa

2006-01-01

The change of the concentration of 7 Be in air and 14 C in the tree ring, cosmogenic nuclide, was measured by the ultralow level radioactivity measurement method. The concentration of 14 C in the tree ring was changed by the intensity of cosmic ray in the past. Cosmic ray and cosmogenic nuclide, solar activity and change of cosmic ray intensity, the continuous measurement of 7 Be concentration in atmosphere, and measurement of 14 C concentration in the old tree ring are reported. 14 C concentration in tree ring is measured by the ultralow level liquid scintillation measuring system (Quantulus) and 14 C concentration in the tree ring of Japanese cedar at Akita and Murou was changed by nuclear tests in air. 14 C concentration of Chokaijindaisugi, cryptomeria, about 2500 years old, is changed periodically about 10.1 years as almost same as the sunspot activity cycle. (S.Y.)

14C Records from Indonesian Sea

International Nuclear Information System (INIS)

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

2013-01-01

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

Instruments Measuring Integrated Care: A Systematic Review of Measurement Properties.

Science.gov (United States)

Bautista, Mary Ann C; Nurjono, Milawaty; Lim, Yee Wei; Dessers, Ezra; Vrijhoef, Hubertus Jm

2016-12-01

-centered care (49%); fewer studies measured care continuity/comprehensive care (15%) and care coordination/case management (3%). We mapped 84% of the measured constructs to the clinical integration domain of the RMIC, with fewer constructs related to the domains of professional (3.7%), organizational (3.4%), and functional (0.5%) integration. Only 8% of the instruments were mapped to a combination of domains; none were mapped exclusively to the system or normative integration domains. The majority of instruments were administered to either patients (60%) or health care providers (20%). Of the measurement properties, responsiveness (4%), measurement error (7%), and criterion (12%) and cross-cultural validity (14%) were less commonly reported. We found measurement properties. Only a minority of index instruments showed strong evidence of positive findings for internal consistency (15%), content validity (19%), and structural validity (7%); with moderate evidence of positive findings for internal consistency (14%) and construct validity (14%). Our results suggest that the quality of measurement properties of instruments measuring integrated care is in need of improvement with the less-studied constructs and domains to become part of newly developed instruments. © 2016 Milbank Memorial Fund.

Instruments Measuring Integrated Care: A Systematic Review of Measurement Properties

Science.gov (United States)

BAUTISTA, MARY ANN C.; NURJONO, MILAWATY; DESSERS, EZRA; VRIJHOEF, HUBERTUS JM

2016-01-01

integration (33%) and patient‐centered care (49%); fewer studies measured care continuity/comprehensive care (15%) and care coordination/case management (3%). We mapped 84% of the measured constructs to the clinical integration domain of the RMIC, with fewer constructs related to the domains of professional (3.7%), organizational (3.4%), and functional (0.5%) integration. Only 8% of the instruments were mapped to a combination of domains; none were mapped exclusively to the system or normative integration domains. The majority of instruments were administered to either patients (60%) or health care providers (20%). Of the measurement properties, responsiveness (4%), measurement error (7%), and criterion (12%) and cross‐cultural validity (14%) were less commonly reported. We found measurement properties. Only a minority of index instruments showed strong evidence of positive findings for internal consistency (15%), content validity (19%), and structural validity (7%); with moderate evidence of positive findings for internal consistency (14%) and construct validity (14%). Conclusions Our results suggest that the quality of measurement properties of instruments measuring integrated care is in need of improvement with the less‐studied constructs and domains to become part of newly developed instruments. PMID:27995711

Measurement of {sup 14}C time scale of the rings of a tree by accelerator mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Oda, Hirotaka; Furukawa, Michiaki [Nagoya Univ. (Japan). School of Science; Yonenobu, Hitoshi; Ikeda, Akiko; Nakamura, Toshio

1996-12-01

{sup 14}C time scale is different from a histrical data in order that it is calculated by assuming that the concentration of {sup 14}C in the sample has not been changed by age. The object of this work is to make clear the errors in measurement of {sup 14}C time scale of the ring of a tree known the tree age. The every year ring of a Hinoki in Kiso, 950 years old, was used as a sample. The most external ring is determined as 1923 years old on the basis of the dendrochronology. The rings after 1120 years were used as the samples. {alpha}-cellulose, the most stable component in the structural components of cell of tree, was prepared from each ring. About 8 mg of {alpha}-cellulose was reduced to graphite to be measured by the tandem thoron analytic meter. The results obtained showed that {sup 14}C time scale was older than that of the histrical data in the twelfth and thirteenth century, but it was more new than that of the histrical data from the late seventeenth to the middle of eighteenth century. The results were agreement with that of Stuiver and Pearson (1933). (S.Y.)

The DSS-14 C-band exciter

Science.gov (United States)

Rowan, D. R.

1989-01-01

The development and implementation of a C-band exciter for use with the Block IV Receiver-Exciter Subsystem at Deep Space Station 14 (DSS-14) has been completed. The exciter supplements the standard capabilities of the Block IV system by providing a drive signal for the C-band transmitter while generating coherent translation frequencies for C-band (5-GHz) to S-band (2.2- to 2.3-GHz) Doppler extraction, C-band to L-band (1.6-GHz) zero delay measurements, and a level calibrated L-band test signal. Exciter functions are described, and a general explanation and description of the C-band uplink controller is presented.

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

Energy Technology Data Exchange (ETDEWEB)

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

1991-03-01

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

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.

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

International Nuclear Information System (INIS)

Maul, N.; Scherling, D.

1989-01-01

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

The role of the archaeologist in C-14 age measurement. Appendix II

International Nuclear Information System (INIS)

Harkness, D.D.

1975-01-01

A C-14 date may be considered to exist in two forms: (a) the 'conventional age' as reported by C-14 laboratories and/or published in the journal Radiocarbon, and (b) the so-called 'corrected age' derived after recourse to half-life changes and calibration curves or tables. While a great deal of advice has been presented to the archaeologist on how he should best correct and interpret the basic conventional C-14 date the importance of his role in ensuring its validity has been largely neglected. This article would hope to clarify where and why the archaeologist can assist in the practical aspects of dating and in so doing also answer such familiar questions as: which sample material is most suited to the production of a valid C-14 date; how much material is required; how are samples best collected, recorded, stored and transported. (author)

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

International Nuclear Information System (INIS)

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

2005-01-01

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

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

International Nuclear Information System (INIS)

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

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1995-01-01

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

Processing ix spent resin waste for C-14 isotope recovery

International Nuclear Information System (INIS)

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

1991-01-01

A process developed at Ontario Hydro for recovering carbon-14 (C-14) from spent ion exchange resin wastes is described. Carbon-14 is an undesirable by-product of CANDU 1 nuclear reactor operation. It has an extremely long (5730 years) half-life and can cause dosage to inhabitants by contact, inhalation, or through the food cycle via photosynthesis. Release of carbon-14 to the environment must be minimized. Presently, all the C-14 produced in the Moderator and Primary Heat Transport (PHT) systems of the reactor is effectively removed by the respective ion exchange columns, and the spent ion exchange resins are stored in suitably engineered concrete structures. Because of the large volumes of spent resin waste generated each year this method of disposal by long term storage tends to be uneconomical; and may also be unsatisfactory considering the long half-life of the C-14. However, purified C-14 is a valuable commercial product for medical, pharmaceutical, agricultural, and organic chemistry research. Currently, commercial C-14 is made artificially in research reactors by irradiating aluminum nitride targets for 4.5 years. If the C-14 containing resin waste can be used to reduce this unnecessary production of C-14, the total global build-up of this radioactive chemical can be reduced. There is much incentive in removing the C-14 from the resin waste to reduce the volume of C-14 waste, and also in purifying the recovered C-14 to supply the commercial market. The process developed by Ontario Hydro consists of three main steps: C-14 removal from spent resins, enrichment of recovered C-14, and preparation of final product. Components of the process have been successfully tested at Ontario Hydro's Research Division, but the integration of the process is yet to be demonstrated. A pilot scale plant capable of processing 4 m 3 of spent resins annually is being planned for demonstrating the technology. The measured C-14 activity levels on the spent resins ranged from 47

Wine ethanol C-14 as a tracer for fossil fuel CO2 emissions in Europe : Measurements and model comparison

NARCIS (Netherlands)

Palstra, Sanne W. L.; Karstens, Ute; Streurman, Harm-Jan; Meijer, Harro A. J.

2008-01-01

C-14 (radiocarbon) in atmospheric CO2 is the most direct tracer for the presence of fossil-fuel-derived CO2 (CO2-ff). We demonstrate the C-14 measurement of wine ethanol as a way to determine the relative regional atmospheric CO2-ff concentration compared to a background site ("regional CO2-ff

Determination of 14CO2 in breath and 14C in stool after oral administration of cholyl-1-[14C]glycine: clinical application

International Nuclear Information System (INIS)

Roda, A.; Roda, E.; Aldini, R.; Mazzella, G.; Festi, D.; Sama, C.; Barbara, L.

1977-01-01

Twenty patients with intestinal bacterial overgrowth and 20 control subjects were investigated for bile acid deconjugation, by measuring 14 CO 2 in the breath after cholyl-1-[ 14 C]glycine administration. 14 CO 2 output/24 h was 11.0 +- 5.2% (mean +- SD) in controls and 54.2 +- 14.0% (mean +- SD) in bacterial-overgrowth patients (P 14 CO 2 excretion rate in 12 h, when normalized to 100% of the dose at the 12th hour, gave an even finer discrimination between the two groups (no false responses). 14 C in stool, analyzed in 20 malabsorption patients and 20 controls by two different techniques, was 6.6 +- 4% and 31.38 +- 20.7% (mean +- SD), respectively. Results by the two different techniques described here correlated well (r = 0.99). Bile acid malabsorption was in reasonable agreement (r = 0.67) with percentage of ''chenoid'' (chenodeoxycholic acid plus ursodeoxycholic acid) in the stool by gas-liquid chromatography; a poorer correlation was observed when ''choloid'' (cholic acid plus its epimers) were plotted vs. 14 C in stool

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Effects of hepatic ischemia-reperfusion injury on the blood-brain barrier permeability to [14C] and [13C]sucrose.

Science.gov (United States)

Miah, Mohammad K; Bickel, Ulrich; Mehvar, Reza

2017-12-01

Hepatic encephalopathy that is associated with severe liver failure may compromise the blood-brain barrier (BBB) integrity. However, the effects of less severe liver diseases, in the absence of overt encephalopathy, on the BBB are not well understood. The goal of the current study was to investigate the effects of hepatic ischemia-reperfusion (IR) injury on the BBB tight junction permeability to small, hydrophilic molecules using the widely used [ 14 C]sucrose and recently-proposed alternative [ 13 C]sucrose as markers. Rats were subjected to 20 min of hepatic ischemia or sham surgery, followed by 8 h of reperfusion before administration of a single bolus dose of [ 14 C] or [ 13 C]sucrose and collection of serial (0-30 min) blood and plasma and terminal brain samples. The concentrations of [ 14 C] and [ 13 C]sucrose in the samples were determined by measurement of total radioactivity (nonspecific) and LC-MS/MS (specific), respectively. IR injury significantly increased the blood, plasma, and brain concentrations of both [ 14 C] and [ 13 C]sucrose. However, when the brain concentrations were corrected for their respective area under the blood concentration-time curve, only [ 14 C]sucrose showed significantly higher (30%) BBB permeability values in the IR animals. Because [ 13 C]sucrose is a more specific BBB permeability marker, these data indicate that our animal model of hepatic IR injury does not affect the BBB tight junction permeability to small, hydrophilic molecules. Methodological differences among studies of the effects of liver diseases on the BBB permeability may confound the conclusions of such studies.

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

International Nuclear Information System (INIS)

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

1989-01-01

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

Study of reaction mechanism for 12C(14N, 6Li) by angular correlation measurement

International Nuclear Information System (INIS)

Goldberg, V.Z.; Golovkov, M.S.; Rogatchev, G.V.; Barrov, S.P.; Zurmuhle, R.W.; Liu, Z.; Benton, D.R.; Miao, Y.; Lee, C.; Wimer, N.G.; Murgatroyd, J.T.; Li, X.

1999-01-01

An angular correlation for the reaction 12 C ( 14 N, 6 Li) 20 Ne* (α) populating the 8.78 MeV (6 + ) level in 20 Ne is measured at 48 MeV incident 14 N energy. 6 Li is registered for 0-degree geometry in coincidence with α particles from the 20 Ne excited state decay. The results shows that 20% was the upper limit for the contribution of compound nucleus formation. Possible main direct mechanisms of the reaction are discussed [ru

Scenarios for 14C release to the atmosphere by the world nuclear industry and estimated radiological impacts

International Nuclear Information System (INIS)

Till, J.E.; Killough, G.G.

1978-01-01

This paper presents an assessment of the radiation dose to the world population and the associated potential health effects from three scenarios of 14 C releases by the nuclear industry between 1975 and 2020. Measures of health impact are derived from source terms through the use of a multicompartment model of the global carbon cycle, dose-rate factors based on 14 C specific activity in various organs of man, and health-effect incidence factors recently recommended by the International Commission on Radiological Protection. The scenarios for worldwide 14 C releases considered are (1) a pessimistic scenario in which all the 14 C projected to be produced in fuel cycles is released, (2) an optimistic scenario that assumes a decontamination factor of 100 for fuel reprocessing, and (3) an intermediate scenario that simulates a phased improvement in effluent treatment technology at reprocessing plants. The estimates of cumulative potential health effects are based on integrations over infinite time. Comparisons with estimated effects from naturally formed 14 C are shown

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

International Nuclear Information System (INIS)

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

2002-01-01

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

S-factor measurement of the 13C(p,γ)14N reaction in reverse kinematics

International Nuclear Information System (INIS)

Genard, G; Terwagne, G; Descouvemont, P

2010-01-01

We measure the S-factor of the 13 C(p,γ) 14 N reaction in reverse kinematics for energies ranging from 561 down to 225 keV with a low background experimental setup. The results are compared with previous measurements and an R-matrix treatment is applied to the data in order to obtain the properties of the 511 keV resonance that dominates the cross section at low energies.

Do site-specific radiocarbon measurements reflect localized distributions of 14C in biota inhabiting a wetland with point contamination sources?

Science.gov (United States)

Yankovich, T; King-Sharp, K J; Benz, M L; Carr, J; Killey, R W D; Beresford, N A; Wood, M D

2013-12-01

Duke Swamp is a wetland ecosystem that receives (14)C via a groundwater pathway originating from a waste management area on Atomic Energy Canada Limited's Chalk River Laboratories site. This groundwater reaches the surface of the swamp, resulting in relatively high (14)C levels over an area of 146 m(2). The objective of this study was to quantify (14)C concentrations in flora and fauna inhabiting areas of Duke Swamp over the gradient of (14)C activity concentrations in moss to determine whether (14)C specific activities in receptor biota reflect the localized nature of the groundwater source in the swamp. Representative receptor plants and animals, and corresponding air and soil samples were collected at six sites in Duke Swamp with (14)C specific activities in air that ranged from 1140 to 45,900 Bq/kg C. In general, it was found that specific activities of (14)C in biota tissues reflected those measured in environmental media collected from the same sampling site. The findings demonstrate that mosses could be used in monitoring programs to ensure protection of biota in areas with elevated (14)C, negating the need to capture and euthanize higher organisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simplified analytical methods for the measurement of the synthesis rate of plasma proteins in vivo by the (/sup 14/C)carbonate method

Energy Technology Data Exchange (ETDEWEB)

Caine, S [Glasgow Royal Infirmary (UK); Fleck, A [Charing Cross Hospital, London (UK). Medical School

1984-09-01

A method is described for obtaining the specific activity of /sup 14/C in urea, essential in the measurement of the synthesis rate of a plasma protein in vivo, which is simpler than the original procedure. The principle is the measurement of /sup 14/CO/sub 2/ and NH/sub 4//sup +/ separately, after incubation with urease. A simple alteration gives samples of /sup 13/CO/sub 2/ for mass spectrometry. The 'recoveries' of /sup 14/C and /sup 13/C in urea were invariably between 90 and 96% and the CV was 3%.

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

International Nuclear Information System (INIS)

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

1988-01-01

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

The measurement of neutron differential scattering cross sections for 12C, 14N and 16O in the energy range 20-26 Mev

International Nuclear Information System (INIS)

Petler, J.S.; Finlay, R.W.; Meigooni, A.S.; Islam, M.S.; Rapaport, J.

1985-01-01

The Ohio University Beam Swinger provides a high resolution, low back-ground time-of-flight facility for the measurement of elastic and inelastic neutron scattering. It has been used to obtain a comprehensive set of differential scattering cross sections for 12 C, 14 N, 16 O and 40 Ca between 18 and 26 MeV. The elastic cross sections can be used directly to obtain partial kerma factors and, combined with the known total cross sections, provide accurate values for the reaction cross sections. Angular distributions have been measured for inelastic scattering from all the nuclear levels that cannot decay by particle emission thus providing (by subtraction) a limit on the sum of all charged-particle producing reactions. The integrated cross sections for inelastic scattering from some particle-unstable states in 12 C are in excellent agreement with the cross sections for three-body breakup obtained by Antolkovic et al. The differential data have been used, together with higher energy proton scattering data to produce energy-dependent optical model parameters for each of these nuclei in the energy range 20-60 MeV. It has been found that the elastic differential cross sections at theta > 100 0 for 12 C, 14 N and 16 O cannot be well described by a spherical optical model. Explicit consideration of coupled-channel effects, and in the case of 12 C, deformation of the ground state, improves the agreement between calculation and experiment. Heavy ion recoil kerma factors and reaction cross sections have been obtained for each element and compared with previous calculations and measurements

Synthesis of [2-13C, 2-14C] 2-aminoethanol, [1-13C, 1-14C] 2-chloroethylamine, N,N'-bis([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(BCNU) and N-([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(CNU)

International Nuclear Information System (INIS)

Narayan, R.; Chang, C-j.

1982-01-01

[2- 13 C, 2- 14 C]2-Aminoethanol hydrochloride was prepared in good yield from Na*CN in a two step sequence by first converting the Na*CN to OHCH 2 *CN and then reducing the nitrile directly with a solution of borane-tetrahydrofuran complex. The reaction procedure was simple and the pure product could be obtained readily. Using this specifically labelled precursor, the synthesis of [1- 13 C, 1- 14 C]2-chloroethylamine hydrochloride, N-([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(CNU) and N,N'-bis([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(BCNU) in good yield without isotope scrambling was also reported. (author)

Use of radio-active carbon (/sup 14/C) for measuring organic production in the sea

Energy Technology Data Exchange (ETDEWEB)

Nielsen, E S

1952-01-01

A method for measuring the photosynthesis of plankton algae in a water sample by means of assimilated /sup 14/C is described. It is shown that the assimilation of /sup 14/C in organic matter otherwise than by photosynthesis is of quite insignificant importance. An account is given of the isotope effect in photosynthesis. Two different methods for the measurement of production of matter per surface unit are described. In the first method samples of water are taken from the various depths and transferred to bottles with glass stoppers. After addition of /sup 14/C, the bottles are suspended at the depths from which the samples were taken, and left there from noon to sunset, for instance. In the other method the bottles are placed in a water-bath which is illuminated by a definite light intensity. The penetration of light in the sea is determined at the same time. The production of matter per surface unit is calculated by means of a formula involving the determination of the depth at which 1 per cent of the total amount of green and blue light occurs, and measurement of the intensities of assimilation in water-bath. The formula, which applies to the tropics, has been derived by comparing the results from all tropical stations, at which observations by the two methods were made simultaneously. The values found for production of matter on a section across the Indian Ocean are recorded. The net production of matter for all sea regions on the globe is estimated at about 1.5 x 10/sup +10/ tons of carbon per year, which is slightly less than the amount produced on land, and the hitherto accepted figures for the production of matter in the sea have proved to be greatly exaggerated.

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

Energy Technology Data Exchange (ETDEWEB)

Rudolph, J.; Weiss, W.

1976-07-01

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

A critical review of atmospheric 14 C activities

International Nuclear Information System (INIS)

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

2006-01-01

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

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

International Nuclear Information System (INIS)

Gonzalez I, J.

1977-01-01

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Secretin enhances [14C]erythritol clearance in unanesthetized dogs

International Nuclear Information System (INIS)

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

1982-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1975-12-22

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

Effect of endomycorrhizae on the bioavailability of bound 14C residues to onion plants from an organic soil treated with [14C]fonofos

International Nuclear Information System (INIS)

Nelson, S.D.; Khan, S.U.

1990-01-01

Uptake of bound 14 C residues from an organic soil treated with radiolabeled fonofos (O-ethyl S-phenyl ethylphosphonodithioate) by selected Glomus endomycorrhiza and onion roots was studied. The hyphae of endomycorrhizal associations were capable of removing 14 C residues from the soil and transporting them to onion plants. Bioavailability of soil-bound 14 C residues, as measured by 14 C residue content in onion, was increased 32 and 40% over that of nonmycorrhizal plants by hyphae of Glomus intraradices and Glomus vesiculiferium, respectively. The data suggest that under field conditions endomycorrhizal infection may greatly increase the bioavailability of soil-bound pesticide residues to plants

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

NARCIS (Netherlands)

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

1998-01-01

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

Physical Research Laboratory radiocarbon 14C dates : CS-I

International Nuclear Information System (INIS)

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

1978-01-01

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

14C Analysis of protein extracts from Bacillus spores.

Science.gov (United States)

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

2014-07-01

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

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.

On-line measurement of 13C/12C and 15N/14N ratios by E/A-diluter-IRMS

International Nuclear Information System (INIS)

Foerstel, H.; Boner, M.; Prast, H.

2001-01-01

Efficient food control requires rapid procedures for testing source authenticity. Food is produced inside a closed 'isotopic environment' from where it inherits a specific isotopic composition or fingerprint. Isotope ratio mass spectrometry (IRMS) measures isotopic compositions using simple gases like CO 2 or N 2 exclusively. From food samples these gases may be produced by combustion in a commercial CHN analyser (Elemental Analyser, EA). Following GC separation of the combustion gases the elemental content is determined using a thermal conductivity detector (TCD) . The effluent of the EA is coupled to the mass spectrometer via an open split. Because the relative amounts of the bio-elements vary significantly, (often C/N is 25/1 or larger), the amount of analyte gas produced from a single sample must be adjusted e.g. using a diluter. Our diluter configuration can be adjusted to measure repeatedly the 13 C/ 12 C ratio of carbon dioxide in mineral waters, as well as to measure 15 N/ 14 N and 13 C/ 12 C ratios from biological or soil samples simultaneously. In the first application different types of carbon dioxide, produced naturally (well) or technically (process), can be distinguished. The second application offers the possibility to trace the fate of a fertilizer in vineyards by determining the isotopic variation of nitrogen and carbon in soil and vines. (author)

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

International Nuclear Information System (INIS)

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

2002-01-01

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

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

NARCIS (Netherlands)

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

2017-01-01

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

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

International Nuclear Information System (INIS)

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

1983-01-01

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

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

International Nuclear Information System (INIS)

Tarpley, L.; Vietor, D.M.

1991-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1989-04-01

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

Forensic applications of 14C bomb-pulse dating

International Nuclear Information System (INIS)

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

2004-01-01

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

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.

Measuring chlorophyll a and 14C-labeled photosynthate in aquatic angiosperms by the use of a tissue solubilizer

International Nuclear Information System (INIS)

Beer, S.; Stewart, A.J.; Wetzel, R.G.

1982-01-01

A compound that quantitatively correlated with chlorophyll a could be measured fluorometrically in the extracts of leaves of three aquatic angiosperms (Myriophyllum heterophyllum Michx., Potamogeton crispus L., Elodea canadensis Michx.) treated with the tissue solubilizer BTS-450. Fluorescent characteristics of the solubilized plant tissues were stable for several weeks in the dark at temperatures up to 60 0 C but rapidly degraded in sunlight or when acidified. 14 C-Labeled photosynthate, which had been fixed by leaf discs during 1- to 10-hour exposure to H 14 CO 3 , was also readily extracted by the tissue solubilizer. Solubilizer extraction can, therefore, be use to determine both chlorophyll a content and 14 C incorporation rates in the same leaf sample. The method is practical, because no grinding is required, the fluorescent characteristics of the extracts are stable, and analyses can be performed with very little plant material

Review of C-14 inventory for the SFR facility

Energy Technology Data Exchange (ETDEWEB)

Smith, Graham; Merino, Joan; Kerrigan, Emma

2002-08-01

The Swedish Radiation Protection Authority (SSI) is currently reviewing SKB's continuing assessment for disposal of radioactive waste to the SFR facility at Forsmark. Among the wastes disposed are reactor operating wastes. Among the relevant radionuclides is C-14, which is relatively difficult to measure and to control because of its mobility. This report documents a review of the C-14 inventory material submitted by SKB for the SFR-facility, to determine its validity and comment on the appropriate assumptions for C-14 content of wastes due to be disposed of to the SFR. The review is based on information provided by SSI as well as other relevant international experience. Conclusions are drawn upon: the chemical form of the C-14 in the waste from BWRs and PWRs; the production rate of C-14 in BWRs and PWRs and quantification of the source term in the IEX waste; the distribution of the C-14 in the IEX waste from BWR between the resins used for treatment of the primary cooling water and the resins used for treatment of the condensate water; quantification of the uncertainties. A suggestion is made that the C-14 inventory could be better developed based upon a mass balance assessment of all the C-14 produced in reactors, and its ultimate fate in effluent and solid wastes, taking account of the reactor specific operational factors identified in the review as relevant to C-14 inventory assessment.

Review of C-14 inventory for the SFR facility

International Nuclear Information System (INIS)

Smith, Graham; Merino, Joan; Kerrigan, Emma

2002-08-01

The Swedish Radiation Protection Authority (SSI) is currently reviewing SKB's continuing assessment for disposal of radioactive waste to the SFR facility at Forsmark. Among the wastes disposed are reactor operating wastes. Among the relevant radionuclides is C-14, which is relatively difficult to measure and to control because of its mobility. This report documents a review of the C-14 inventory material submitted by SKB for the SFR-facility, to determine its validity and comment on the appropriate assumptions for C-14 content of wastes due to be disposed of to the SFR. The review is based on information provided by SSI as well as other relevant international experience. Conclusions are drawn upon: the chemical form of the C-14 in the waste from BWRs and PWRs; the production rate of C-14 in BWRs and PWRs and quantification of the source term in the IEX waste; the distribution of the C-14 in the IEX waste from BWR between the resins used for treatment of the primary cooling water and the resins used for treatment of the condensate water; quantification of the uncertainties. A suggestion is made that the C-14 inventory could be better developed based upon a mass balance assessment of all the C-14 produced in reactors, and its ultimate fate in effluent and solid wastes, taking account of the reactor specific operational factors identified in the review as relevant to C-14 inventory assessment

Comparison of accelerator mass spectrometric measurement with liquid scintillation counting measurement for the determination of 14C in environmental samples

International Nuclear Information System (INIS)

Yasuike, Kaeko; Yamada, Yoshimune; Amano, Hikaru

2010-01-01

The concentrations of organically-bound 14 C in tree-ring cellulose of a Japanese Black Pine grown in Shika-machi (37.0 deg. N, 136.8 deg. E) and those of a Japanese Cedar grown in Kanazawa (36.5 deg. N, 136.7 deg. E), Japan, were analyzed for the ring-years from 1989 to 1998 by the accelerator mass spectrometric measurement. The results were compared with those of the same samples analyzed by the liquid scintillation counting measurement to determine the reliability of liquid scintillation counting measurement. An important result of this study is that the sensitivity and reproducibility of accelerator mass spectrometric measurement was almost equal to that of liquid scintillation counting measurement.

Historical 14C measurement from the Atlantic, Pacific, and Indian Oceans. Progress report, December 1, 1978-August 31, 1979

International Nuclear Information System (INIS)

Fairhall, A.W.

1979-01-01

Between the years 1964 and 1974, over 1000 sea water samples were collected from various locations and depths to 4000 M. These samples were processed to recover inorganic carbon (as CO 2 ) for laboratory measurement of 14 C. Aliquots of sea water, poisoned with mercuric chloride, were collected at the same time for total CO 2 measurement. During laboratory workup approximately 1/2 of the samples had small aliquots of CO 2 set aside for 13 C/ 12 C isotope ratio measurement. The purpose of the present project is to finalize all of this information along with the hydrographic data for each station

Radiocarbon C-14 dating - MINT experience

International Nuclear Information System (INIS)

Kamisah Alias

2002-01-01

The measurement of a radiocarbon date is a complex process which involved all the stages from advice given prior to submission of samples right through to reporting of results. The aim of our radiocarbon dating is to determine the residual 14 C content of a sample, the value of which is translated into an age that is an estimate of the time elapsed since the given sample was removed from the environment in which it had formed in equilibrium with respect to 14-C radioactive decay and metabolic assimilation. Carbon is obtained from carbon containing samples in the form of carbon dioxide, which is then reacted with lithium forming lithium carbide. The carbide is then hydrolysed to acetylene before it was polymerised to benzene using a high-efficiency vanadium-alumina-silica catalyst to produce benzene with up to 96% yield. Sample, background and modem standard activities are measured with a coincidence scintillation counter using in glass vials of 21 ml capacity. An improved chemical procedure was used to obtain and purify the benzene from the samples for measurement using a liquid scintillation counter. Radiocarbon dating measurements of samples collected reveal some results. The validity of the data have yet to be confirmed by the results of the measurements on two international control samples. (Author)

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

International Nuclear Information System (INIS)

Giaquinta, R.; Beyer, E. Jr.

1977-01-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Dating human DNA with the 14C bomb peak

Energy Technology Data Exchange (ETDEWEB)

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

2013-07-01

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

Scenarios of 14C releases from the World Nuclear Power Industry from 1975 to 2020 and the estimated radiological impact

International Nuclear Information System (INIS)

Killough, G.G.; Till, J.E.

1978-01-01

This article presents an assessment of the radiation dose to the world population and the associated potential health effects from three scenarios of 14 C releases by the nuclear industry between 1975 and 2020. Measures of health impact are derived from source terms through the use of a multicompartment model of the global carbon cycle, dose-rate factors based on 14 C specific activity in various organs of man, and health-effect incidence factors recently recommended by the International Commission on Radiological Protection (ICRP). The three scenarios for worldwide 14 C releases considered are (1) a pessimistic scenario in which all the 14 C projected to be produced in fuel cycles is released (2) an optimistic scenario that assumes a decontamination factor of 100 for fuel reprocessing, and (3) an intermediate scenario that simulates a phased improvement in the effluent treatment technology at reprocessing plants. The estimates of cumulative potential health effects based on integration over infinite time (effectively 46,000 years or about 8 half-lives of 14 C) are as follows: 110,000 cancers and 75,000 genetic effects from the pessimistic scenario; 21,000 cancers and 14,000 genetic effects from the optimistic scenario; 22,000 cancers and 15,000 genetic effects from the intermediate scenario; 100,000 cancers and 68,000 genetic effects from the 14 C formed in nature between 1975 and 2020; and 380,000 cancers and 250,000 genetic effects from the 14 C formed by the detonation of nuclear explosives from 1945 to 1974. Comparable effects from the naturally formed 14 C in steady state in the environment, also integrated over 46,000 years, are approximately 66 million cancers and 43 million genetic effects. These estimates are based on a world population that is assumed to remain stationary at 12.2 billion after 2075

Synthesis of pinacolyl [14C]methylphosphonochloridate

International Nuclear Information System (INIS)

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

1982-01-01

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

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

International Nuclear Information System (INIS)

Kolina, J.; Hromadkova, B.

1989-01-01

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

Temperature effects on Microalgal Photosynthesis-Light responses measured by O2 production, Pulse-Amplitude-Modulated Fluorescence, and 14C assimilation

DEFF Research Database (Denmark)

Hancke, Kasper; Hancke, Torunn; Olsen, Lasse M.

2008-01-01

Short-term temperature effects on photosynthesis were investigated by measuring O2 production, PSII-fluorescence kinetics, and 14C-incorporation rates in monocultures of the marine phytoplankton species Prorocentrum minimum (Pavill.) J. Schiller (Dinophyceae), Prymnesium parvum f. patelliferum ( J....... C. Green, D. J. Hibberd et Pienaar) A. Larsen (Coccolithophyceae), and Phaeodactylum tricornutum Bohlin (Bacillariophyceae), grown at 15 oC and 80 umol photons m-2 s-1. Photosynthesis versus irradiance curves were measured at seven temperatures (0oC to 30oC) by all three approaches. The maximum...

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

International Nuclear Information System (INIS)

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

1978-01-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Monitoring of the 14C activity in the atmosphere

International Nuclear Information System (INIS)

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

2006-01-01

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

Preparation of arginine (guanide 14C)

International Nuclear Information System (INIS)

Pichat, L.; Baret, C.

1960-01-01

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

Analysis of Δ14C variations in atmosphere

International Nuclear Information System (INIS)

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

2005-01-01

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

Use of natural diamonds to monitor 14C AMS instrument backgrounds

International Nuclear Information System (INIS)

Taylor, R.E.; Southon, John

2007-01-01

To examine one component of the instrument-based background in University of California Keck Carbon Cycle AMS spectrometer, we have obtained measurements on a set of natural diamonds pressed into sample holders. Natural diamond samples (N = 14) from different sources within rock formations with geological ages greatly in excess of 100 Ma yielded a range of currents (∼110-250 μA 12 C - where filamentous graphite typically yields ∼150 μA 12 C - ) and apparent 14 C ages (64.9 ± 0.4 ka BP [0.00031 ± 0.00002 fm] to 80.0 ± 1.1 ka BP [0.00005 ± 0.00001 fm]). Six fragments cut from a single diamond exhibited essentially identical 14 C values - 69.3 ± 0.5 ka-70.6 ± 0.5 ka BP. The oldest 14 C age equivalents were measured on natural diamonds which exhibited the highest current yields

A new 14C AMS facility at IUAC, New Delhi

International Nuclear Information System (INIS)

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

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1995-12-31

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

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

International Nuclear Information System (INIS)

Kitagawa, Hiroyuki

2013-01-01

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

Synthesis of cholesterol 26. C{sup 14} (1961); Synthese du cholesterol {sup 14}C-26 (1961)

Energy Technology Data Exchange (ETDEWEB)

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

1961-07-01

Cholesterol 26 {sup 14}C is synthesized from methylmagnesium iodide {sup 14}C with a 48 per cent overall yield. Cholesterol is purified by chromatography on alumina. The various intermediates of the synthesis are characterized by thin-layer chromatography according to Stahl. (authors) [French] Le cholesterol {sup 14}C-26 est synthetise a partir d'iodure de methyl magnesium {sup 14}C, avec un rendement de 48 pour cent par rapport a l'iodure de methyl {sup 14}C mis en jeu. Le cholesterol est purifie par chromatographie sur alumine. Les intermediaires de la synthese sont caracterises par chromatographie en couche mince, selon Stahl. (auteurs)

The bomb 14C transient in the Pacific Ocean

Science.gov (United States)

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

2000-04-01

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

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

International Nuclear Information System (INIS)

Loester, H.; Seim, H.

1996-01-01

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

14C and 13C in the atmosphere and soil air at two localities of Slovakia

International Nuclear Information System (INIS)

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

2006-01-01

In this paper there are presented the long-term measurements of 13 R and 14 R in urban and countryside atmosphere. The different conditions and particularities of both the localities which influence on the mentioned characteristics are pointed out. The existence of δ 13 C and δ 14 C variations and their phase correlation were confirmed as well as their origin were qualitatively explained. By means of the non-linear regression and harmonic analysis the trends of δ 13 C and δ 14 C variations was found. The study of δ 13 C and δ 14 C courses has shown that it can be used as an effective tool to determine the level of the anthropogenic CO 2 pollution of the atmosphere. (authors)

Synthesis of 14C and 32P double labelled triethylphosphine

International Nuclear Information System (INIS)

Kanska, M.; Drabarek, S.

1979-01-01

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

Synthesis of 14C-dehydrocorydaline chloride

International Nuclear Information System (INIS)

Zhang Rui; Wang Ding

1988-01-01

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

Synthesis of [5,6-13C2, 1-14C]olivetolic acid, methyl [1'-13C]olivetolate and [5,6-13C2, 1-14C]cannabigerolic acid

International Nuclear Information System (INIS)

Porwoll, J.P.; Leete, E.

1985-01-01

Potential advanced intermediates in the biosynthesis of delta 9 -tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous 13 C atoms and 14 C. Methyl [5,6- 13 C 2 , 1- 14 C]olivetolate was prepared from lithium [ 13 C 2 ]acetylide and dimethyl [2- 14 C]malonate. Reaction with geranyl bromide afforded methyl [5,6- 13 C 2 , 1- 14 C]cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The 13 C- 13 C couplings observable in the 13 C NMR spectra of these 13 C-enriched compounds and their synthetic precursors are recorded. Methyl [1'- 14 C]olivetolate was prepared from 13 CO 2 to confirm assignments of the 13 C chemical shifts in the pentyl side chain of these compounds. (author)

Biodegradation of [14C]phenol in secondary sewage and landfill leachate measured by double-vial radiorespirometry

International Nuclear Information System (INIS)

Deeley, G.M.; Skierkowski, P.; Robertson, J.M.

1985-01-01

Double-vial radiorespirometry was used to estimate the biodegradation rates of 14 C-labeled phenol in a landfill leachate and a secondary treated domestic wastewater. Rates were found to be comparable for each material at each of the three concentrations tested. Sewage microorganisms immediately began biodegrading the [ 14 C]phenol; landfill leachate microorganisms required a lag period before maximum biodegradation of the [ 14 C]phenol. The apparent rate of [ 14 C]phenol biodegradation was 2.4 times faster in the sewage than in the landfill leachate. Double-vial radiorespirometry was shown to be an effective method for screening biodegradation rates in aquifers

Bepaling van 14C in afvalwater

NARCIS (Netherlands)

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

1998-01-01

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

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

African Journals Online (AJOL)

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

Reduced permeation of 14C-sucrose, 3H-mannitol and 3H-inulin across blood-brain barrier in nephrectomized rats

International Nuclear Information System (INIS)

Preston, E.; Haas, N.; Allen, M.

1984-01-01

Experiments were carried out to determine if changes in the concentration-time profile of a blood-borne radiotracer such as 14 C-sucrose would spuriously alter measurements of its permeation across the blood-brain barrier (permeability-area product, PA) based on a 2-compartment (plasma/brain) simple diffusion model. Anesthetized rats which were bilaterally nephrectomized and given a standard intravenous bolus injection of 14 C-sucrose, 3 H-mannitol or 3 H-inulin exhibited an elevated plasma tracer concentration compared to control animals. However, tracer concentration measured in brain parenchyma after 30 min was not proportionally elevated, and PA calculated from the ratio, parenchymal tracer concentration: plasma concentration-time integral, was significantly reduced below control values. In control rats, distortion and elevation of the plasma 14 C-sucrose profile by continuous intravenous infusion did not result in lowered PA values. This suggested that the lowering of PA by nephrectomy reflected reduced cerebrovascular permeability or area or other cerebral influence rather than a deficiency in the 2-compartment model for PA measurement

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

International Nuclear Information System (INIS)

Barthe, P.; Bulard, C.

1981-01-01

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

Report on interlaboratory comparisons of 14C measurements organized by the environmental research branch, Chalk River Laboratories

International Nuclear Information System (INIS)

Milton, G.M.; Kramer, S.J.; Cooper, E.L.; Rao, R.R.; Milton, J.C.D.

1996-02-01

The need for increased quality assurance for measurements performed by the monitoring laboratories at nuclear stations has spurred the introduction of a number of laboratory intercomparisons. This report provides details of two intercomparisons of 14 C measurements, including the preparation of potential secondary reference materials, the range of analytical techniques in use at the participating laboratories, and a statistical analysis of the results reported. The agreement evident in the two sets of materials - milk and vegetation - was good. (author)

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.

Sources of C-14 generation and associated doses; Fuentes de generacion de C-14 y dosis asociadas

Energy Technology Data Exchange (ETDEWEB)

Amado, Valeria A; Biaggio, Alfredo L; Canoba, Analia C; Curti, Adriana R. [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina)], E-mail: vamado@cae.arn.gov.ar

2009-07-01

C-14 is a radioactive isotope of C with a half-life of 5700 years that decays to N-14 by emission of beta radiation. It is naturally produced in the upper atmosphere by cosmic ray neutrons via the (n;p) reaction over N-14. Anthropogenic C-14 has been generated in the past by atmospheric nuclear weapon tests and it is currently produced during the operation of nuclear reactors. Once released this radionuclide behaves in the biosphere as the standard carbon cycle. Since the beginning of the industrial period the relationship Carbon-14/Stable Carbon has changed continuously, and so the dose incurred by the world population. In this paper the main anthropogenic activities that modified such relationship are presented and analyzed: the Suess effect and the generation of nuclear energy. It is concluded that the current trend of reduction of the total dose due to C-14 will continue during the next decades. Finally it is indicated that in order to prevent an excessive accumulation of this radionuclide in the biosphere, actions should be collectively implemented to be effective. (author) [Spanish] El C-14 es un isotopo radiactivo del C con un periodo de semidesintegracion igual a 5700 anios y que decae a N-14 por emision de radiacion beta. Se produce naturalmente en las altas capas de la atmosfera debido a la reaccion N-14(n,p)C-14 inducida por neutrones lentos de rayos cosmicos. El C-14 antropogenico se genero debido a los ensayos nucleares y actualmente es producido durante la operacion de los reactores nucleares. Una vez liberado se incorpora a la biosfera a traves del ciclo del carbono. A partir de los inicios del periodo industrial la relacion C-14/C-estable, y por ende la dosis debida a C-14 que recibiria la poblacion mundial, ha variado continuamente. El objetivo del presente trabajo es presentar y analizar los distintos factores antropogenicos que modifican la concentracion de C-14, en particular el efecto Suess y la generacion de energia nuclear. Se observa que las

First results of a simultaneous measurement of tritium and 14C in an ultra-low-background proportional counter for environmental sources of methane

Energy Technology Data Exchange (ETDEWEB)

Mace, Emily K.; Aalseth, Craig E.; Day, Anthony R.; Hoppe, Eric W.; Keillor, Martin E.; Moran, James J.; Panisko, Mark E.; Seifert, Allen; Tatishvili, Gocha; Williams, Richard M.

2016-02-01

Abstract Simultaneous measurement of tritium and 14C would provide an added tool for tracing organic compounds through environmental systems and is possible via beta energy spectroscopy of sample-derived methane in internal-source gas proportional counters. Since the mid-1960’s atmospheric tritium and 14C have fallen dramatically as the isotopic injections from above-ground nuclear testing have been diluted into the ocean and biosphere. In this work, the feasibility of simultaneous tritium and 14C measurements via proportional counters is revisited in light of significant changes in both the atmospheric and biosphere isotopics and the development of new ultra-low-background gas proportional counting capabilities for small samples (roughly 50 cc methane). A Geant4 Monte Carlo model of a Pacific Northwest National Laboratory (PNNL) proportional counter response to tritium and 14C is used to analyze small samples of two different methane sources to illustrate the range of applicability of contemporary simultaneous measurements and their limitations. Because the two methane sources examined were not sample size limited, we could compare the small-sample measurements performed at PNNL with analysis of larger samples performed at a commercial laboratory. The dual-isotope simultaneous measurement is well matched for methane samples that are atmospheric or have an elevated source of tritium (i.e. landfill gas). For samples with low/modern tritium isotopics (rainwater), commercial separation and counting is a better fit.

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.

Detection of 14C in natural trace organics recovered from groundwater

International Nuclear Information System (INIS)

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

1985-01-01

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Probable alpha and 14C cluster emission from hyper Ac nuclei

International Nuclear Information System (INIS)

Santhosh, K.P.

2013-01-01

A systematic study on the probability for the emission of 4 He and 14 C cluster from hyper Λ 207-234 Ac and non-strange normal 207-234 Ac nuclei are performed for the first time using our fission model, the Coulomb and proximity potential model (CPPM). The predicted half lives show that hyper Λ 207-234 Ac nuclei are unstable against 4 He emission and 14 C emission from hyper Λ 217-228 Ac are favorable for measurement. Our study also show that hyper Λ 207-234 Ac are stable against hyper Λ 4 He and Λ 14 C emission. The role of neutron shell closure (N = 126) in hyper Λ 214 Fr daughter and role of proton/neutron shell closure (Z ∼ 82, N = 126) in hyper Λ 210 Bi daughter are also revealed. As hyper-nuclei decays to normal nuclei by mesonic/non-mesonic decay and since most of the predicted half lives for 4 He and 14 C emission from normal Ac nuclei are favourable for measurement, we presume that alpha and 14 C cluster emission from hyper Ac nuclei can be detected in laboratory in a cascade (two-step) process. (orig.)

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

International Nuclear Information System (INIS)

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

2004-01-01

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

Distribution of (14 C) photosynthates in 3 periods during the plant-cane cycle

International Nuclear Information System (INIS)

Pimentel, R.M.M.

1989-04-01

Plant-cane stools were labelled with 14 CO 2 in the field, at Goiana-PE, Brazil, when 3,7 and 11 months old. Each stool was enclosed in a chamber with 14 CO 2 for 90 minutes. The 14 C photosynthates were measured in leaves, stalks, roots and soil 1, 7, 15, 30, 60 and 90 days after labelling. Roots were divided into alive and dead and soil into rizosphere and outer soil. The soil was incubated for 10 days to measure C mineralization. At end of the labelling period at 3,7 and 11 months, 2, 19 and 1% of the initial 14 CO 2 were recovered in the plant and the soil. The low recovery of 14 C at 3 months could be attributed to losses by respiration and lack of sampling of the top growing point. The low CO 2 fixation and losses by respiration at first sampling in the 7 months old labelling were attributed to low light intensity during the day of labelling. In the following sampling, total 14 C recoveries varied little and there was little change in the proportion of 14 C in each part, indicating that the 14 C was already incorporated in stable organic fractions. Most of the recovered 14 C C>80%) was founded in the leaves but all plant parts received labelled photosynthates. (author)

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}.

Use of the [14C]Leucine Incorporation Technique To Measure Bacterial Production in River Sediments and the Epiphyton

OpenAIRE

Fischer, Helmut; Pusch, Martin

1999-01-01

Bacterial production is a key parameter for the understanding of carbon cycling in aquatic ecosystems, yet it remains difficult to measure in many aquatic habitats. We therefore tested the applicability of the [14C]leucine incorporation technique for the measurement of bulk bacterial production in various habitats of a lowland river ecosystem. To evaluate the method, we determined (i) extraction efficiencies of bacterial protein from the sediments, (ii) substrate saturation of leucine in sedi...

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

International Nuclear Information System (INIS)

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

1981-01-01

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

Measurement of human blood brain barrier integrity using 11C-inulin and positron emission tomography

International Nuclear Information System (INIS)

Hara, Toshihiko; Iio, Masaaki; Tsukiyama, Takashi

1988-01-01

Positron emission tomography (PET) using 11 C-inulin was demonstrated to be applicable to the clinical measurement of blood brain barrier permeability and cerebral interstitial fluid volume. Kinetic data were analyzed by application of a two compartment model, in which blood plasma and interstitial fluid spaces constitute the compartments. The blood activity contribution was subtracted from the PET count with the aid of the 11 CO inhalation technique. The values we estimated in a human brain were in agreement with the reported values obtained for animal brains by the use of 14 C-inulin. (orig.)

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

Synthesis of C-9-14C-1,8-dihydroxy-3-carboxyanthraquinone

International Nuclear Information System (INIS)

De Witte, P.; Lemli, J.

1988-01-01

The synthesis of C-9- 14 C-rhein is reported using 14 CO 2 as a 14 C-source. After preparing 14 C-1, 8-dimethoxy-3-methylanthraquinone by a condensation reaction, the product is demethylated and the 3-methyl group converted to the corresponding 3-carboxy group. The radio-active yield of the total synthesis, starting with 1 Ci 14 CO 2 is 6,9% (6, 9 mCi); 352 mg 14 rhein is produced with a specific activity of 55,7 mCi/mmol. (author)

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

International Nuclear Information System (INIS)

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

1991-01-01

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

Synthesis of DL-adrenaline (methyl C{sup 14}) (1961); Synthese de la DL-adrenaline (methyle {sup 14}C) (1961)

Energy Technology Data Exchange (ETDEWEB)

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

1961-07-01

The sodium derivative of 5-3-4 dibenzyl oxyphenyl 2-oxazolidinone reacted with methyl iodide {sup 14}C, in stoichiometric quantity, gives rise to the corresponding N-methyl {sup 14}C derivative. The oxazolidinone ring is opened by concentrated hydrochloric acid and the benzyl groups removed by catalytic hydrogenolysis. Adrenaline methyl {sup 14}C is then purified on Dowex 50 X-12 exchange resin. Overall-yield is 45 per cent based upon methyl iodide {sup 14}C. (author) [French] Le derive sode de la (dibenzyloxy-3-4-phenyl)-5 oxazolidinone-2 traite par l'iodure de methyle {sup 14}C, en proportion stoechiometrique, fournit le derive N-methyle {sup 14}C correspondant. Apres ouverture du cycle oxazolidinone par HCL concentre et debenzylation par hydrogenation catalytique, on purifie l'adrenaline (methyle {sup 14}C) par chromatographie sur resine echangeuse Dowex 50 X-12. Le rendement est de 45 pour cent par rapport a l'iodure de methyle {sup 14}C. (auteurs)

Synthesis of DL-adrenaline (methyl C{sup 14}) (1961); Synthese de la DL-adrenaline (methyle {sup 14}C) (1961)

Energy Technology Data Exchange (ETDEWEB)

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

1961-07-01

The sodium derivative of 5-3-4 dibenzyl oxyphenyl 2-oxazolidinone reacted with methyl iodide {sup 14}C, in stoichiometric quantity, gives rise to the corresponding N-methyl {sup 14}C derivative. The oxazolidinone ring is opened by concentrated hydrochloric acid and the benzyl groups removed by catalytic hydrogenolysis. Adrenaline methyl {sup 14}C is then purified on Dowex 50 X-12 exchange resin. Overall-yield is 45 per cent based upon methyl iodide {sup 14}C. (author) [French] Le derive sode de la (dibenzyloxy-3-4-phenyl)-5 oxazolidinone-2 traite par l'iodure de methyle {sup 14}C, en proportion stoechiometrique, fournit le derive N-methyle {sup 14}C correspondant. Apres ouverture du cycle oxazolidinone par HCL concentre et debenzylation par hydrogenation catalytique, on purifie l'adrenaline (methyle {sup 14}C) par chromatographie sur resine echangeuse Dowex 50 X-12. Le rendement est de 45 pour cent par rapport a l'iodure de methyle {sup 14}C. (auteurs)

Liquid scintillation measurements of aqueous 14C or 3H containing samples in a toluene cocktail

International Nuclear Information System (INIS)

Engelmann, A.; Reinhard, G.

1980-01-01

On the basis of investigations of the ternary system toluene/methanol/water that composition of toluene/methanol scintillation cocktails has been determined, which allows liquid scintillation measurements of 14 C or 3 H containing samples in homogeneous distribution. Because of more pronounced quenching the optimum sample quantity was less for blood solutions extracted with a HClO 4 /H 2 O 2 mixture than for water. The effect of beta radiation energy has to be taken into account. (author)

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

International Nuclear Information System (INIS)

Liebl, J. C.

2011-01-01

Radiocarbon (14C, t 1/2 = 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

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

Energy Technology Data Exchange (ETDEWEB)

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

1958-07-01

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

Simultaneous 13C/14C dual isotope breath test measurement of gastric emptying of solid and liquid in normal subjects and patients: comparison with scintigraphy

International Nuclear Information System (INIS)

Chew, C. G.; Bartholomeusz, F.D.L.; Bellon, M.; Chatterton, B. E.

2003-01-01

To develop a simple method for simultaneous solid and liquid gastric emptying assessment using a dual isotope labelled breath test. 13 patients were given 100 g ground beef labelled with 25 MBq 99m Tc sulphur colloid and 74 KBq 14 C octanoic acid, and 150 ml 10% glucose drink labelled with 8 MBq 67 Ga citrate and 150 mg 13 C acetate. 10 normal volunteers were given the same test meals but labelled with 14 C and 13 C only. Breath was collected at baseline and regularly for 4 hours. The 14 CO 2 and 13 CO 2 activity was measured with liquid scintillation counting and mass spectroscopy. The times to maximum 14 CO 2 and 13 CO 2 , were determined. Comparison was made between times to maximum 14 CO 2 with scintigraphic retention of 99m Tc at 100 minutes and times to maximum 13 CO 2 with the scintigraphic half-clearance time of 67 Ga. For the solid meal, the times to maximum 14 CO 2 were: 60-120 minutes in the 8 patients with normal gastric emptying of 99m Tc; 75-145 minutes for the 10 healthy volunteers; 75-180 minutes for the remaining 5 patients with abnormal gastric emptying of 99m Tc. There was a weak but significant correlation (r = 0.56, p 14 CO 2 and gastric retention of 99m Tc at 100 minutes. For the liquid meal, times to maximum 13 CO 2 were: 20-35 minutes for the 4 with normal gastric emptying of 67 Ga; 15-40 minutes for the 10 healthy volunteers; 20-75 minutes for the remaining 9 patients with abnormal gastric emptying of 67 Ga. There was a strong and significant correlation (r = 0.88, p 13 CO 2 and gastric half-clearance time of 67 Ga. Breath tests utilising test meals labelled with *C isotopes are valid alternatives to scintigraphic studies using 99m Tc and 67 Ga for the simultaneous assessment of gastric emptying of solids and liquids. (author)

Fine structures in 14C emission of 223Ra and 224Ra

International Nuclear Information System (INIS)

Hourani, E.; Rosier, L.; Berrier-Ronsin, G.; Elayi, A.; Mueller, A.C.; Rappenecker, G.; Rotbard, G.; Renou, G.; Liebe, A.; Stab, L.

1991-01-01

The measurement of the energy spectrum of 14 C nuclei emitted in the spontaneous radioactivity from 223 Ra and 224 Ra has been carried out, using thin and intense sources (480 MBq for 223 Ra and 3550 MBq for 224 Ra). The sources were obtained by implanting mass-separated beams from ISOLDE (CERN) into Al and vitreous C catchers. The measurement was performed with the supraconducting solenoidal spectrometer SOLENO installed at Orsay. The discovery, of a fine structure in the energy spectrum of 14 C emission from 223 Ra, which is analogous to the one known for α emission, is confirmed. Only 13% of the branching ratio in 14 C decay leads to the ground state of the residual nucleus, while 8l% to the first excited state. For 14 C emission of 224 Ra, a lower limit of 2 for the hindrance factor has been measured for the transition to the first excited state in the residual nucleus. Also, a precise identification in Z with a E·ΔE telescope has been performed for the radiation from the 223 Ra source. (author) 22 refs., 11 figs., 1 tab

14C Accelerator mass spectrometry in Brazil

International Nuclear Information System (INIS)

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

2011-01-01

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

Metabolic kinetics and biological effects of radiocarbon (14C)

International Nuclear Information System (INIS)

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

1988-01-01

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

Measurement of L-[1-14C]leucine kinetics in splanchnic and leg tissues in humans. Effect of amino acid infusion

International Nuclear Information System (INIS)

Gelfand, R.A.; Glickman, M.G.; Castellino, P.; Louard, R.J.; DeFronzo, R.A.

1988-01-01

Although whole-body leucine flux is widely measured to study body protein turnover in humans, the contribution of specific tissues to the total-body measurement remains unknown. By combining the organ-balance technique with the systemic infusion of L-[1-14C]leucine, we quantitated leucine production and disposal by splanchnic and leg tissues and by the whole body, simultaneously, in six normal men before and during amino acid infusion. At steady state, disposal of arterial leucine by splanchnic and leg tissues was calculated from the percent extraction (E) of L-[1-14C]leucine counts: uptake = E x [Leu]a x flow. Tissue release of cold leucine (from protein turnover) into vein was calculated as the difference between leucine uptake and the net tissue leucine balance. In the postabsorptive state, despite substantial (P less than .01) extraction of L-[1-14C]leucine by splanchnic (23 +/- 1%) and leg (18 +/- 2%) tissues, net leucine balance across both tissue beds was small, indicating active simultaneous disposal and production of leucine at nearly equivalent rates. Splanchnic tissues accounted for approximately 50% of the measured total-body leucine flux. During amino acid infusion, the net leucine balance across splanchnic and leg tissues became positive, reflecting not only an increase in leucine uptake but also a marked suppression (by approximately 50%, P less than .02) of cold leucine release. This reduction in splanchnic and leg leucine release was indicated by a sharp decline in whole-body endogenous leucine flux

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

International Nuclear Information System (INIS)

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

1987-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1986-05-01

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

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

International Nuclear Information System (INIS)

Becker, W.

1984-01-01

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

The distribution of 14C-chitosan by different molecular weight in mice

International Nuclear Information System (INIS)

Kim, Kwang Yoon; Kim, Young Ho; Bom, Hee Seung; Kim, Ji Yeul; Kim, Hee Kyung; Roh, Young Bok; Nishimura, Yoshikazu

1998-01-01

Chitosan is a nontoxic natural chealtor which was made by chitin, and reduced a contamination of radiostrontium in animals. In this experiment, a different molecular weight of C-14 chitosan was intravenously administered to mice, and then the distribution of C-14 chitosan in the body was observed. Male mice (8 to 10 weeks, body weight of 30 to 35g) of ICR strain were used. C-14 chitosan, mice was sacrificed at the 6th hour, 1st, 3rd, 5th, and 7th day. Beta radioactivities in the blood, liver, kidney, liver, muscle, testis, and urine was measured using a liquid scintillation analyzer. Most of the C-14 chitosan was excreted through urine within 6 hours. Biodistribution of C-14 chitosan was similar despite the difference of molecular weight. Higher distributions of radioactivities were found in the liver, kidney, spleen. The relative concentration in tissue increased for the 6 hours and then decreased. In conclusion, most of C-14 chitosan was excreted through urine despite the difference of molecular weight. and, low molecular weight of C-14 chitosan showed higher distribution than high molecular weight of C-14 chitosan in tissues

Translocation of 14-C in ponderosa pine seedlings

Science.gov (United States)

Robert R. Ziemer

1971-01-01

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

In vivo survival of [14C]sucrose-loaded porcine carrier erythrocytes

International Nuclear Information System (INIS)

DeLoach, J.R.

1983-01-01

Porcine carrier erythrocyte survival was measured in adult pigs. [14C]Sucrose-loaded erythrocytes had a biphasic survival curve, with as much as 50% of the cells removed from circulation in the first 24 hours. The remaining cells had a 35-day half-life. Encapsulation values were measured for porcine erythrocytes and entrapment of [14C]sucrose was greater than 45%. Addition of inosine and glucose to the dialyzed cells and to the final wash buffer before reinjection of autologous cells did not improve their survival

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.

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

International Nuclear Information System (INIS)

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

1982-01-01

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

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)

Janle, E.; Sojka, J.; Jackson, G.S.; Lachcik, P.; Einstien, J.A.; Santerre, C.R.

2007-01-01

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 14 C can be measured using Accelerator Mass Spectrometry (AMS), a goat model was used to establish a minimum oral dose of 14 C-labeled PCB (2,2',4,4',5,5'-hexachlorobiphenyl-UL- 14 C) 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 14 C 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

Synthesis of [14C]Zolpidem

International Nuclear Information System (INIS)

Allen, J.; Tizot, A.

1986-01-01

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

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

International Nuclear Information System (INIS)

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

2004-01-01

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

Flux density measurements of radio sources at 2.14 millimeter wavelength

International Nuclear Information System (INIS)

Cogdell, J.R.; Davis, J.H.; Ulrich, B.T.; Wills, B.J.

1975-01-01

Flux densities of galactic and extragalactic sources, and planetary temperatures, have been measured at 2.14 mm wavelength (140 GHz). Results are presented for OJ 287; the galactic sources DR 21, W3, and Orion A; the extragalactic sources PKS 0106plus-or-minus01, 3C 84, 3C 120, BL Lac, 3C 216, 3C 273, 3C 279, and NGC 4151; and the Sun, Venus, Mars, and Jupiter. Also presented is the first measurement of the 2.14-mm temperature of Uranus. The spectra of some of these sources are discussed. The flux density scale was calibrated absolutely. The measurements were made with a new continuum receiver on the 4.88-m radio telescope of The University of Texas

Discharges of [sup 14]C from nuclear facilities; Implication in environmental science

Energy Technology Data Exchange (ETDEWEB)

Iwakura, Tetsuo (Japan Chemical Analysis Center, Chiba (Japan))

1993-10-01

At present as C-14 existing in environment, there are that formed by cosmic ray in nature, by nuclear explosion experiment and released from nuclear facilities. As for the former two, the actual situation has been grasped, but the last one lacks the sure information as the range of its influence is local. In this study, the actual situation was explored based on the numerical evaluation of the amount generated in nuclear facilities and the investigative and analytical data by actual measurement. The rate of formation of natural C-14 is closely related to the variation of cosmic ray intensity and energy spectra. The specific radioactivity is 12.9 - 15.3 dpm/g, and it lowers due to the Suess effect, namely the increase of dead carbon. The C-14 due to nuclear explosion experiment reached the highest level of twice as much as the natural level in 1963, but thereafter, it decreased, and at present, it is 15-20% more than the natural level. The nuclear reaction and the reaction cross section of C-14 formation in LWRs, LMFBRs and HTGRs are shown. The formation of C-14 in fuel, core structures and cooling water of LWRs and in other types of reactors, and the examples of C-14 measurement around nuclear facilities are reported. (K.I.).

A convenient method for 14C-labeling of 2-methylthio-1-[4-N-α-ethoxycarbonylbenzyl)-amino-benzyl] -5-hydroxymethyl-2-[14C]-1H-imidazole and 1-[4-N-α-ethoxy-carbonylbenzyl)-aminobenzyl]-5-hydroxymethyl-2-[14C] -1H-imidazole as potential antihypertensives

International Nuclear Information System (INIS)

Nader Saemian; Gholamhossein Shirvani; Mohsen Javaheri; Sayed Sajad Oliyaee

2012-01-01

The key synthetic intermediate, (2-mercapto-1-(4-nitrobenzyl)-1H-imidazol-5-yl)methanol-[2- 14 C], has been synthesized by using one pot procedure from potassium[ 14 C]-thiocyanate. It was converted to two nonpeptide angiotensin II receptor antagonists, 2-methylthio-1-[4-N-α-ethoxycarbonyl benzyl)-aminobenzyl]-5-hydroxymethyl-1H-imidazole-[2- 14 C] and 1-[4-N-α-ethoxy-carbonylbenzyl)-aminobenzyl] -5-hydroxymethyl-1H-imidazole-[2- 14 C] via a 3-step sequence synthetic pathway. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Barthe, P.; Bulard, C.

1981-01-01

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

Integration of C1 and C2 Metabolism in Trees

OpenAIRE

Jardine, Kolby J.; Fernandes de Souza, Vinicius; Oikawa, Patty; Higuchi, Niro; Bill, Markus; Porras, Rachel; Niinemets, Ülo; Chambers, Jeffrey Q.

2017-01-01

C1 metabolism in plants is known to be involved in photorespiration, nitrogen and amino acid metabolism, as well as methylation and biosynthesis of metabolites and biopolymers. Although the flux of carbon through the C1 pathway is thought to be large, its intermediates are difficult to measure and relatively little is known about this potentially ubiquitous pathway. In this study, we evaluated the C1 pathway and its integration with the central metabolism using aqueous solutions of 13C-labele...

Biokinetics and dosimetry of radioactively labelled organic C-14 compounds

International Nuclear Information System (INIS)

Krins, A.; Sahre, P.; Schoenmuth, T.

2003-12-01

The report starts with summarising research work and the resulting scientific information in connection with the dosimetry of C-14 labelled organic compounds. Biokinetic models are developed for compounds such as benzene, phenol, aniline, nitrobenzene, and a selection of pharmaceuticals, in order to show the radioactivity distribution after administration of the C-14 labelled substances. Based on the those models, dose coefficients and excretion rates are derived. The following synoptic view of the available data library leads on to a discussion of various aspects, as eg. the question of whether and how monitoring for detection of incorporation of C-14 administered with labelled organic compounds is possible. None of the questions and aspects arising in connection with this subject can be adequately dealt with in the present document, but concepts and methods are presented which permit an interpretation of radioactivity excretion data measured after incorporation of C-14 labelled organic substances. (orig./CB) [de

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-01-15

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

Extraction and analysis of 14C-carbofuran radioactivity in soil sample

International Nuclear Information System (INIS)

Maizatul Akmam Mhd Nasir; Nashriyah Mat

2005-01-01

Carbofuran insecticide or nematicide sprayed onto soil in the agroecosystem will be taken up by plant. Carbofuran residue will pollute the environment and organisms in the food chain. Extraction and analysis of 14 C-carbofuran in soil from lysimeter were carried out. The Liquid Scintillation Counter (LSC) was used to measure radioactivity of 14 C-carbofuran in soil sample. (Author)

Monte Carlo calculations and measurements of spectra from a C-14 source

International Nuclear Information System (INIS)

Borg, J.

1996-05-01

To perform Monte Carlo simulations it is necessary to model the physical geometries i.e., the source and detector geometry. However, a complete model of the physical geometry may not be possible or may result in a very low calculation efficiency. Substituting the complete source model with a simplified model is one way of increasing the calculation efficiency. In this report, the study of a simplified model of a 14 C source is described. Results of Monte Carlo calculations with the EGS4 code are compared with measurements with a β spectrometer consisting of two coaxial Si detectors, and a low-energy photon spectrometer being a Si(Li) detector. Calculations and measurements show generally good agreement. However, the difference (a factor of 4) between calculated and measured response to electrons for the Si(Li) detector indicates that this detector has a dead layer about 12 μm thick instead of 0.2 μm as reported by the manufacturer. The efficiency of the calculations is increased by a factor of 10, when the complete source model is replaced by the simplified source model. This reduces the calculation time of detector responses to a few days instead of weeks on the NRC SGI R4400 computers. Good agreement between measured and calculated data also verifies that the MC code EGS4 is a reliable and useful tool for simulating coupled electron and photon transport for particles with energies down to a few keV. (au) 3 tabs., 15 ills., 11 refs

May 14C be used to date contemporary art?

International Nuclear Information System (INIS)

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

2013-01-01

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

A rapid microwave induced synthesis of [carboxyl-14C]-nicotinic acid (vitamin B3) and [carbonyl-14C]-nicotinamide using K14CN

International Nuclear Information System (INIS)

Ravi, S.; Mathew, K.M.; Sivaprasad, N.

2008-01-01

Microwave assisted direct aromatic substitution of 3-bromopyridine with K 14 CN as the cyanide source and catalytic amount of tetrabutylammonium bromide afforded [3- 14 C]-cyanopyridine 3 in 90% yield. Microwave assisted hydrolysis of 3 with a mixture of concentrated hydrochloric acid and propionic acid afforded [carboxyl- 14 C]-nicotinic acid in 95% yield whereas microwave assisted hydrolysis of 3 with a mixture of concentrated sulfuric acid and propionic acid afforded [carbonyl- 14 C]-nicotinamide in 85% yield. (author)

Synthesis of 14C-labelled milrinone

International Nuclear Information System (INIS)

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

1985-01-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Carbon-14 dating of tree rings for tritium measurement

International Nuclear Information System (INIS)

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

1998-01-01

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

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

International Nuclear Information System (INIS)

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

2001-01-01

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

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).

Seasonal variations and sources of ambient fossil and biogenic-derived carbonaceous aerosols based on 14C measurements in Lhasa, Tibet

Science.gov (United States)

Huang, Jie; Kang, Shichang; Shen, Chengde; Cong, Zhiyuan; Liu, Kexin; Wang, Wei; Liu, Lichao

2010-06-01

A total of 30 samples of total suspended particles were collected at an urban site in Lhasa, Tibet from August 2006 to July 2007 for investigating carbonaceous aerosol features. The fractions of contemporary carbon ( fc) in total carbon (TC) of ambient aerosols are presented using radiocarbon ( 14C) measurements. The value of fc represents the biogenic contribution to TC, as the biosphere releases organic compounds with the present 14C/ 12C level ( fc = 1), whereas 14C has become extinct in anthropogenic emissions of fossil carbon ( fc = 0). The fc values in Lhasa ranging from 0.357 to 0.702, are higher than Beijing and Tokyo, but clearly lower than the rural region of Launceston, which indicates a major biogenic influence in Lhasa. Seasonal variations of fc values corresponded well with variations of pollutants concentrations (e.g. NO 2). Higher fc values appeared in winter indicating carbonaceous aerosol is more dominated by wood burning and incineration of agricultural wastes within this season. The lower fc values in summer and autumn may be caused by increased diesel and petroleum emissions related to tourism in Lhasa. δ13C values ranged from - 26.40‰ to - 25.10‰, with relative higher values in spring and summer, reflecting the increment of fossil carbon emissions.

Low-level (submicromole) environmental 14C metrology

International Nuclear Information System (INIS)

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

2000-01-01

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

14CO2 measurements in maritime air over the Northern Indian Ocean

International Nuclear Information System (INIS)

Dutta, K.; Bhushan, R.; Somayajulu, B.L.K.

2002-01-01

14 C in the carbon dioxide of air overlying the Northern Indian Ocean was measured during the spring of 1993 to 1995 and 1997 to 1999. Considerable variations of 14 C over this region have been observed during this period, which reflect both regional and interannual variations. The interannual variations of 14 C of the tropospheric CO 2 over this region is found to correlate with the El Nino/Southern Oscillation (ENSO) events, with positive excursions of 14 C before the onset of warm phase of ENSO. (author)

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

Rapid analysis method for the determination of 14C specific activity in irradiated graphite.

Science.gov (United States)

Remeikis, Vidmantas; Lagzdina, Elena; Garbaras, Andrius; Gudelis, Arūnas; Garankin, Jevgenij; Plukienė, Rita; Juodis, Laurynas; Duškesas, Grigorijus; Lingis, Danielius; Abdulajev, Vladimir; Plukis, Artūras

2018-01-01

14C is one of the limiting radionuclides used in the categorization of radioactive graphite waste; this categorization is crucial in selecting the appropriate graphite treatment/disposal method. We propose a rapid analysis method for 14C specific activity determination in small graphite samples in the 1-100 μg range. The method applies an oxidation procedure to the sample, which extracts 14C from the different carbonaceous matrices in a controlled manner. Because this method enables fast online measurement and 14C specific activity evaluation, it can be especially useful for characterizing 14C in irradiated graphite when dismantling graphite moderator and reflector parts, or when sorting radioactive graphite waste from decommissioned nuclear power plants. The proposed rapid method is based on graphite combustion and the subsequent measurement of both CO2 and 14C, using a commercial elemental analyser and the semiconductor detector, respectively. The method was verified using the liquid scintillation counting (LSC) technique. The uncertainty of this rapid method is within the acceptable range for radioactive waste characterization purposes. The 14C specific activity determination procedure proposed in this study takes approximately ten minutes, comparing favorably to the more complicated and time consuming LSC method. This method can be potentially used to radiologically characterize radioactive waste or used in biomedical applications when dealing with the specific activity determination of 14C in the sample.

Rapid analysis method for the determination of 14C specific activity in irradiated graphite.

Directory of Open Access Journals (Sweden)

Vidmantas Remeikis

Full Text Available 14C is one of the limiting radionuclides used in the categorization of radioactive graphite waste; this categorization is crucial in selecting the appropriate graphite treatment/disposal method. We propose a rapid analysis method for 14C specific activity determination in small graphite samples in the 1-100 μg range. The method applies an oxidation procedure to the sample, which extracts 14C from the different carbonaceous matrices in a controlled manner. Because this method enables fast online measurement and 14C specific activity evaluation, it can be especially useful for characterizing 14C in irradiated graphite when dismantling graphite moderator and reflector parts, or when sorting radioactive graphite waste from decommissioned nuclear power plants. The proposed rapid method is based on graphite combustion and the subsequent measurement of both CO2 and 14C, using a commercial elemental analyser and the semiconductor detector, respectively. The method was verified using the liquid scintillation counting (LSC technique. The uncertainty of this rapid method is within the acceptable range for radioactive waste characterization purposes. The 14C specific activity determination procedure proposed in this study takes approximately ten minutes, comparing favorably to the more complicated and time consuming LSC method. This method can be potentially used to radiologically characterize radioactive waste or used in biomedical applications when dealing with the specific activity determination of 14C in the sample.

Wine ethanol 14C as a tracer for fossil fuel CO2 emissions in Europe: Measurements and model comparison

Science.gov (United States)

Palstra, Sanne W. L.; Karstens, Ute; Streurman, Harm-Jan; Meijer, Harro A. J.

2008-11-01

14C (radiocarbon) in atmospheric CO2 is the most direct tracer for the presence of fossil-fuel-derived CO2 (CO2-ff). We demonstrate the 14C measurement of wine ethanol as a way to determine the relative regional atmospheric CO2-ff concentration compared to a background site ("regional CO2-ff excess") for specific harvest years. The carbon in wine ethanol is directly back traceable to the atmospheric CO2 that the plants assimilate. An important advantage of using wine is that the atmosphere can be monitored annually back in time. We have analyzed a total of 165 wines, mainly from harvest years 1990-1993 and 2003-2004, among which is a semicontinuous series (1973-2004) of wines from one vineyard in southwest Germany. The results show clear spatial and temporal variations in the regional CO2-ff excess values. We have compared our measured regional CO2-ff excess values of 2003 and 2004 with those simulated by the REgional MOdel (REMO). The model results show a bias of almost +3 parts per million (ppm) CO2-ff compared with those of the observations. The modeled differences between 2003 and 2004, however, which can be used as a measure for the variability in atmospheric mixing and transport processes, show good agreement with those of the observations all over Europe. Correcting for interannual variations using modeled data produces a regional CO2-ff excess signal that is potentially useful for the verification of trends in regional fossil fuel consumption. In this fashion, analyzing 14C from wine ethanol offers the possibility to observe fossil fuel emissions back in time on many places in Europe and elsewhere.

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

International Nuclear Information System (INIS)

Pearson, G.W.

1983-01-01

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

Transfer of {sup 14}C to prenatal and neonatal rats from their mothers exposed to {sup 14}C compounds by ingestion

Energy Technology Data Exchange (ETDEWEB)

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

2003-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1994-05-01

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

Utilization of atmospheric C-14 as tracer of soil organic matters

International Nuclear Information System (INIS)

Lobo, P.F.S.

1972-01-01

Two ferrallitics profiles, of the state of Bahia (Brazil), have been analysed and the 14 C/ 12 C ratio of about fifteen samples measured (fulvics acids, humics acids, humin, as extracted by Dalbin's method). The amount of soil that comes up to the surface by the action of Lumbricidae has been estimated for one profile by means of radiometric measurements. (M.A.C.) [pt

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

International Nuclear Information System (INIS)

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

1990-01-01

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

Early incorporation and distribution of 14C-photosynthates after 14C-feeding for a brief period in tea plant

International Nuclear Information System (INIS)

Hakamata, Katsuhiro

1981-01-01

In order to clarify the early incorporation and distribution of 14 C-photosynthetic products in tea plants after 14 C-feeding for a brief period, 14 C-tracer experiments were performed, using the winter leaves, first crop shoots and young tea plants of a cultivar, Yabukita. As the results of the experiment on leaf disks by 14 C-Feeding for one minute, the 14 C-activity in the ethanol soluble fraction distributed in the anionic, cationic and neutral fractions in this order. When the time of feeding was extended to 10 min, the distribution in the cationic fraction decreased, and that in the neutral fraction increased. In the experiment on shoots, after the end of 10 min assimulation, the 14 C-activity in the ethanol soluble fraction distributed in the neutral, cationic and anionic fractions in this order. In course of time, the distribution in the cationic and anionic fractions decreased, and that in the neutral fraction increased. As the results of 14 C-feeding to young tea plants for 2.5 hours, 70 - 95% of the 14 C-activity in the ethanol soluble fraction distributed in the neutral fraction. Sucrose seemed to be the primary and early product of photosynthesis, and might be the principal carbohydrate form of translocation and reserve in tea plants. Raffinose and stachyose played almost the same role as sucrose. (Kako, I.)

Genetic consequences of the 14C-decay

International Nuclear Information System (INIS)

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

1978-03-01

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

[14C]Virginiamycin residues in eggs

International Nuclear Information System (INIS)

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

1988-01-01

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

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

International Nuclear Information System (INIS)

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

1994-01-01

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

Dating of groundwater with tritium and 14C

International Nuclear Information System (INIS)

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

1967-01-01

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

Biokinetic studies on 14C-chitosan in rats

International Nuclear Information System (INIS)

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

1998-05-01

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

Integral measurement of the $^{12}$C(n,p)$^{12}$B reaction up to 10 GeV

CERN Document Server

Žugec, P; Bosnar, D; Ventura, A; Mengoni, A; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Cortés, G; Cortés-Giraldo, M.A; Cosentino, L; Diakaki, M; Domingo-Pardo, C; Dressler, R; Duran, I; Eleftheriadis, C; Ferrari, A; Finocchiaro, P; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Heinitz, S; Jenkins, D G; Jericha, E; Käppeler, F; Karadimos, D; Kivel, N; Kokkoris, M; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Leong, L S; Meo, S Lo; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P; Mastromarco, M; Mendoza, E; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Musumarra, A; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T

2016-01-01

The integral measurement of the $^{12}$C(n,p)$^{12}$B reaction was performed at the neutron time of flight facility n_TOF at CERN. The total number of $^{12}$B nuclei produced per neutron pulse of the n_TOF beam was determined using the activation technique in combination with a time of flight technique. The cross section is integrated over the n_TOF neutron energy spectrum from reaction threshold at 13.6 MeV to 10 GeV. Having been measured up to 1 GeV on basis of the $^{235}$U(n,f) reaction, the neutron energy spectrum above 200 MeV has been reevaluated due to the recent extension of the cross section reference for this particular reaction, which is otherwise considered a standard up to 200 MeV. The results from the dedicated GEANT4 simulations have been used to evaluate the neutron flux from 1 GeV up to 10 GeV. The experimental results related to the $^{12}$C(n,p)$^{12}$B reaction are compared with the evaluated cross sections from major libraries and with the predictions of different GEANT4 models, which m...

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

Science.gov (United States)

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

1964-01-01

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

Integration of palmitat-1-14C in lecithine and phospholipid content in normal and micro-embolized rabbit lungs

International Nuclear Information System (INIS)

Wichert, P. von; Wilke, A.; Gaertner, U.

1975-01-01

Glass microspheres were used for a diffuse pulmonary microembolisation, as a modell for shock lung. Microembolisation is regarded as an important factor in pathogenesis of shock lung. The capacity of lung for lecithin synthesis was measured with palmitat-1- 14 C incorporation. The phospholipid content and the composition of the fatty acids of lecithine were investigated. From the results it was possible, that the surfactant system may alterated by the vascular blocking. The dates supporting the importance of microembolisation in pathogenesis of shock lung. (orig.) [de

The study of variations and environmental applications 14C

International Nuclear Information System (INIS)

Simon, J.

2010-01-01

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

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

Science.gov (United States)

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

2017-12-01

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

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

International Nuclear Information System (INIS)

Kozukue, E.; Mizuno, S.

1987-01-01

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

A model for C-14 tracer evaporative rate analysis (ERA)

International Nuclear Information System (INIS)

Gardner, R.P.; Verghese, K.

1993-01-01

A simple model has been derived and tested for the C-14 tracer evaporative rate analysis (ERA) method. It allows the accurate determination of the evaporative rate coefficient of the C-14 tracer detector in the presence of variable evaporation rates of the detector solvent and variable background counting rates. The evaporation rate coefficient should be the most fundamental parameter available in this analysis method and, therefore, its measurements with the proposed model should allow the most direct correlations to be made with the system properties of interest such as surface cleanliness. (author)

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

International Nuclear Information System (INIS)

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

2006-01-01

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

TENCompetence Learning Design Toolkit, Runtime component, ccsi_v3_2_10c_v1_4

NARCIS (Netherlands)

Sharples, Paul; Popat, Kris; Llobet, Lau; Santos, Patricia; Hernández-Leo, Davinia; Miao, Yongwu; Griffiths, David; Beauvoir, Phillip

2010-01-01

Sharples, P., Popat, K., Llobet, L., Santos, P., Hernandez-Leo, D., Miao, Y., Griffiths, D. & Beauvoir, P. (2009) TENCompetence Learning Design Toolkit, Runtime component, ccsi_v3_2_10c_v1_4 This release is composed of three files corresponding to CopperCore Service Integration (CCSI) v3.2-10cv1.4,

Dicty_cDB: FC-BS14 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available FC (Link to library) FC-BS14 (Link to dictyBase) - - - Contig-U16399-1 FC-BS14E (Li...nk to Original site) - - - - - - FC-BS14E 534 Show FC-BS14 Library FC (Link to library) Clone ID FC-BS14 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BS/FC-BS14Q.Seq.d/ Representative seq. ID FC-BS...14E (Link to Original site) Representative DNA sequence >FC-BS14 (FC-BS14Q) /CSM/FC/FC-BS/FC-BS14Q.Seq.... vs CSM-cDNA Score E Sequences producing significant alignments: (bits) Value FC-BS14 (FC-BS

Sample loading for C-14 measurement in the simulated organic solvent waste from a CANDU Nuclear Power Plant

International Nuclear Information System (INIS)

Dianu, Magdalena; Dobrin, Relu; Podina, Corneliu

2005-01-01

The paper evaluates the performance of two commercially available liquid scintillation cocktails designed for counting nonaqueous (organic) samples. To choose a suitable scintillation cocktail is not always easy because many cocktails are available on the market. The efficiency, sample loading, sample type are all important variables that help determine the suitability of a liquid scintillation cocktail for C-14 measurement. Samples were counted in a 2100 TRI-CARB Packard Model liquid scintillation analyzer. (authors)

Integral measurement of the {sup 12}C(n, p){sup 12}B reaction up to 10 GeV

Energy Technology Data Exchange (ETDEWEB)

Zugec, P.; Bosnar, D. [University of Zagreb, Department of Physics, Faculty of Science, Zagreb (Croatia); Colonna, N.; Barbagallo, M.; Mastromarco, M.; Tagliente, G.; Variale, V. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Ventura, A. [Istituto Nazionale di Fisica Nucleare, Bologna (Italy); Mengoni, A. [ENEA, Bologna (Italy); Altstadt, S.; Langer, C.; Lederer, C.; Reifarth, R.; Schmidt, S.; Weigand, M. [Johann-Wolfgang-Goethe Universitaet, Frankfurt (Germany); Andrzejewski, J.; Marganiec, J.; Perkowski, J. [Uniwersytet Lodzki, Lodz (Poland); Audouin, L.; Leong, L.S.; Tassan-Got, L. [Centre National de la Recherche Scientifique/IN2P3 - IPN, Orsay (France); Becares, V.; Cano-Ott, D.; Garcia, A.R.; Gonzalez-Romero, E.; Martinez, T.; Mendoza, E. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Becvar, F.; Krticka, M.; Kroll, J.; Valenta, S. [Charles University, Prague (Czech Republic); Belloni, F.; Mondalaers, W.; Plompen, A.; Schillebeeckx, P. [European Commission JRC, Institute for Reference Materials and Measurements, Geel (Belgium); Berthoumieux, E.; Fraval, K.; Gunsing, F. [CEA/Saclay - IRFU, Gif-sur-Yvette (France); Billowes, J.; Ware, T.; Wright, T. [University of Manchester, Manchester (United Kingdom); Boccone, V.; Brugger, M.; Calviani, M.; Cerutti, F.; Chiaveri, E.; Chin, M.; Ferrari, A.; Guerrero, C.; Losito, R.; Roman, F.; Rubbia, C.; Tsinganis, A.; Versaci, R.; Vlachoudis, V.; Weiss, C. [CERN, Geneva (Switzerland); Calvino, F.; Cortes, G.; Gomez-Hornillos, M.B.; Riego, A. [Universitat Politecnica de Catalunya, Barcelona (Spain); Carrapico, C.; Goncalves, I.F.; Sarmento, R.; Vaz, P. [Universidade de Lisboa, C2TN-Instituto Superior Tecnico, Lisboa (Portugal); Cortes-Giraldo, M.A.; Praena, J.; Quesada, J. [Universidad de Sevilla, Sevilla (Spain); Cosentino, L.; Finocchiaro, P. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Diakaki, M.; Karadimos, D.; Kokkoris, M.; Vlastou, R. [National Technical University of Athens (NTUA), Athens (Greece); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. [CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); Dressler, R.; Heinitz, S.; Kivel, N.; Schumann, D. [Paul Scherrer Institut, Villigen (Switzerland); Duran, I.; Tarrio, D. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Eleftheriadis, C.; Manousos, A. [Aristotle University of Thessaloniki, Thessaloniki (Greece); Ganesan, S.; Gurusamy, P.; Saxena, A. [Bhabha Atomic Research Centre (BARC), Mumbai (India); Griesmayer, E.; Jericha, E.; Leeb, H. [Atominstitut der Oesterreichischen Universitaeten, Technische Universitaet Wien, Wien (Austria); Jenkins, D.G.; Vermeulen, M.J. [University of York, York, Heslington (United Kingdom); Kaeppeler, F. [Karlsruhe Institute of Technology (KIT), Institut fuer Kernphysik, Karlsruhe (Germany); Lo Meo, S. [Istituto Nazionale di Fisica Nucleare, Bologna (Italy); ENEA, Bologna (Italy); Massimi, C.; Mingrone, F.; Vannini, G. [Dipartimento di Fisica, Universita di Bologna (IT); INFN, Bologna (IT); Mastinu, P. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (IT); Milazzo, P.M. [Istituto Nazionale di Fisica Nucleare, Trieste (IT); Mirea, M. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HH, Magurele (RO); Musumarra, A. [Universita di Catania, Dipartimento di Fisica e Astronomia DFA, Catania (IT); INFN-Laboratori Nazionali del Sud, Catania (IT); Paradela, C. [European Commission JRC, Institute for Reference Materials and Measurements, Geel (BE); Universidade de Santiago de Compostela, Santiago de Compostela (ES); Pavlik, A. [Faculty of Physics, University of Vienna, Wien (AT); Rauscher, T. [University of Hertfordshire, Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, Hatfield (GB); University of Basel, Department of Physics, Basel (CH); Wallner, A. [Faculty of Physics, University of Vienna, Wien (AT); Australian National University, Research School of Physics and Engineering, Canberra (AU)

2016-04-15

The integral measurement of the {sup 12}C(n, p){sup 12}B reaction was performed at the neutron time-of-flight facility nTOF at CERN. The total number of {sup 12}B nuclei produced per neutron pulse of the nTOF beam was determined using the activation technique in combination with a time-of-flight technique. The cross section is integrated over the nTOF neutron energy spectrum from reaction threshold at 13.6 MeV to 10 GeV. Having been measured up to 1GeV on basis of the {sup 235}U(n, f) reaction, the neutron energy spectrum above 200 MeV has been re-evaluated due to the recent extension of the cross section reference for this particular reaction, which is otherwise considered a standard up to 200 MeV. The results from the dedicated GEANT4 simulations have been used to evaluate the neutron flux from 1 GeV up to 10 GeV. The experimental results related to the {sup 12}C(n, p){sup 12}B reaction are compared with the evaluated cross sections from major libraries and with the predictions of different GEANT4 models, which mostly underestimate the {sup 12}B production. On the contrary, a good reproduction of the integral cross section derived from measurements is obtained with TALYS-1.6 calculations, with optimized parameters. (orig.)

Concentration and distribution of 14C in aquatic environment around Qinshan nuclear power plant

International Nuclear Information System (INIS)

Wang Zhongtang; Guo Qiuju; Hu Dan; Xu Hong

2015-01-01

In order to study the concentration and distribution of 14 C in aquatic environment in the vicinity of Qinshan Nuclear Power Plant (NPP) after twenty years' operation, an apparatus extracting dissolved inorganic carbon from water was set up and applied to pretreat the water samples collected around Qinshan NPP. The 14 C concentration was measured by accelerator mass spectrometer (AMS). The results show that the 14 C specific activities in surface seawater samples range from 196.8 to 206.5 Bq/kg 203.4 ± 5.6) Bq/kg in average), which are close to the background. The 14 C concentrations in cooling water discharged from Qinshan NPP are close to the 14 C values in near shore seawater samples out of liquid radioactive effluent discharge period. It can be further concluded that the 14 C discharged previously is diluted and diffused well, and no 14 C enrichment in seawater is found. Also, no obvious increment in the 14 C specific activities of surface water and underground water samples are found between Qinshan NPP region and the reference region. (authors)

Using atmospheric 14CO to constrain OH variability: concept and potential for future measurements

Science.gov (United States)

Petrenko, V. V.; Murray, L. T.; Smith, A. W.

2017-12-01

The primary source of 14C-containing carbon monoxide (14CO) in the atmosphere is via 14C production from 14N by secondary cosmic rays, and the primary sink is removal by OH. Variations in the global abundance of 14CO that are not explained by variations in 14C production are mainly driven by variations in the global abundance of OH. Monitoring OH variability via methyl chloroform is becoming increasingly difficult as methyl chloroform abundance is continuing to decline. Measurements of atmospheric 14CO have previously been successfully used to infer OH variability. However, these measurements are currently only continuing at one location (Baring Head, New Zealand), which is insufficient to infer global trends. We propose to restart global 14CO monitoring with the aim of providing another constraint on OH variability. A new analytical system for 14CO sampling and measurements is in development, which will allow to strongly reduce the required sample air volumes (previously ≥ 400 L) and simplify field logistics. A set of test measurements is planned, with sampling at the Mauna Loa Observatory. Preliminary work with a state-of-the-art chemical transport model is identifying the most promising locations for global 14CO sampling.

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-01-15

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

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

Science.gov (United States)

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

2009-12-01

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

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

Science.gov (United States)

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

1980-04-01

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

Incorporation of 14C-succinate in Synechococcus

International Nuclear Information System (INIS)

Doehler, G.

1983-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1984-01-01

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

Effect of Cold (14° C) vs. Ice (5° C) Water Immersion on Recovery From Intermittent Running Exercise.

Science.gov (United States)

Anderson, Daniel; Nunn, James; Tyler, Christopher J

2018-03-01

Anderson, D, Nunn, J, and Tyler, CJ. Effect of cold (14° C) vs. ice (5° C) water immersion on recovery from intermittent running exercise. J Strength Cond Res 32(3): 764-771, 2018-The purpose was to compare 14° C (CWI14° C) and 5° C (CWI5° C) cold water immersion after intermittent running. On 3 occasions, 9 male team-sport players undertook 12 minutes of CWI14° C, CWI5° C, or nonimmersed seated recovery (CON) after 45 minutes of intermittent running exercise. Maximal cycling performance and markers of recovery were measured before and in the 0-72 hours after exercise. Peak power output (PPO) was immediately reduced after all interventions (d = 1.8). CWI5° C was more effective at restoring PPO than CWI14° C (d = 0.38) and CON (d = 0.28) 24 hours after exercise, whereas both CON (d = 0.20) and CWI5 (d = 0.37) were more effective than CWI14° C after 48 hours. Cold water immersion (CWI) was more effective than CON at restoring PPO 72 hours after exercise (d = 0.28-0.30). Mean power output (MPO) was higher in CON compared with CWI5° C (d = 0.30) and CWI14° C (d = 0.21), but there was no difference between CWI5° C and CWI14° C (d = 0.08). CWI5° C was more effective than CWI14° C for restoring MPO to baseline levels 24 hours (d = 0.28) and 72 hours (d = 0.28) after exercise; however, CON was more, or equally, effective as CWI5° C and CWI14° C throughout. Lactate and creatine kinase concentrations were unaffected. Perceived muscle soreness remained elevated in CWI5 and CON throughout but was similar to baseline in CWI14° C after 72 hours. In conclusion, repeated bouts of exercise are initially impaired after 5 and 14° C CWI, but PPO may be improved 72 hours after exercise. Cold water immersion is not recommended for acute recovery based on these data. Athletes and coaches should use the time currently allocated to CWI for more effective and alternative recovery modalities.

Plasma kinetics of 14C-uric acid in bulls

International Nuclear Information System (INIS)

Cetinkaya, N.

1999-01-01

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

Efficiency for C-14 measurement in the simulated hydraulic oil waste from a CANDU nuclear power plant as measured on a packard counter

International Nuclear Information System (INIS)

Dianu, Magdalena; Podina, Corneliu; Nita, Valentina

2005-01-01

Full text: The paper mainly contains; - composition and data on liquid scintillation cocktail used; - characterization of radioactive waste - hydraulic oil waste contaminated with C-14; - detection limits; - sample loading; - the values of calculated and measured activities; - efficiency vs sample loading. Samples were counted in a Model 2100 TR Packard TRI-CARB liquid scintillation analyser. Sample preparation is a critical step in obtaining accurate results in scintillation counting. Standard (22 ml) plastic vials were used in these experiments. These vials have the advantage to reduce backgrounds and improve the counting rate. Hydraulic oil sample volumes were added to the vials in 0.5 ml increments from 1 ml to 2 ml. Then the liquid scintillation cocktail was added so that the sample - cocktail volume was 20 ml. Each vial was shaken vigorously for several seconds after each addition to ensure homogeneity and counting. Blank vials were prepared using C-14 - free hydraulic oil samples in the same sample-cocktail proportions. After at least two hours, the samples and blank vials were counted for ten minutes. (authors)

Determination of the asymptotic normalization coefficients for ¹⁴C + n <--> ¹⁵C, the ¹⁴C(n, gamma)¹⁵C reaction rate, and evaluation of a new method to determine spectroscopic factors

Energy Technology Data Exchange (ETDEWEB)

McCleskey, M; Mukhamedzhanov, A M; Trache, L; Tribble, R E; Banu, A; Eremenko, V; Goldberg, V Z; Lui, Y W; McCleskey, E; Roeder, B T; Spiridon, A; Carstoiu, F; Burjan, V; Hons, Z; Thompson, I J

2014-04-17

The ¹⁴C + n <--> ¹⁵C system has been used as a test case in the evaluation of a new method to determine spectroscopic factors that uses the asymptotic normalization coefficient (ANC). The method proved to be unsuccessful for this case. As part of this experimental program, the ANCs for the ¹⁵C ground state and first excited state were determined using a heavy-ion neutron transfer reaction as well as the inverse kinematics (d,p) reaction, measured at the Texas A&M Cyclotron Institute. The ANCs were used to evaluate the astrophysical direct neutron capture rate on ¹⁴C, which was then compared with the most recent direct measurement and found to be in good agreement. A study of the ¹⁵C SF via its mirror nucleus ¹⁵F and a new insight into deuteron stripping theory are also presented.

14C Behaviour in PWR coolant

International Nuclear Information System (INIS)

Sims, Howard; Dickinson Shirley; Garbett, Keith

2012-09-01

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

Synthesis of (/sup 14/C)Zolpidem

Energy Technology Data Exchange (ETDEWEB)

Allen, J.; Tizot, A.

1986-04-01

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

Transformation of the herbicide [14C]glufosinate in soils

International Nuclear Information System (INIS)

Smith, A.E.

1989-01-01

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

Integration of G protein α (Gα) signaling by the regulator of G protein signaling 14 (RGS14).

Science.gov (United States)

Brown, Nicole E; Goswami, Devrishi; Branch, Mary Rose; Ramineni, Suneela; Ortlund, Eric A; Griffin, Patrick R; Hepler, John R

2015-04-03

RGS14 contains distinct binding sites for both active (GTP-bound) and inactive (GDP-bound) forms of Gα subunits. The N-terminal regulator of G protein signaling (RGS) domain binds active Gαi/o-GTP, whereas the C-terminal G protein regulatory (GPR) motif binds inactive Gαi1/3-GDP. The molecular basis for how RGS14 binds different activation states of Gα proteins to integrate G protein signaling is unknown. Here we explored the intramolecular communication between the GPR motif and the RGS domain upon G protein binding and examined whether RGS14 can functionally interact with two distinct forms of Gα subunits simultaneously. Using complementary cellular and biochemical approaches, we demonstrate that RGS14 forms a stable complex with inactive Gαi1-GDP at the plasma membrane and that free cytosolic RGS14 is recruited to the plasma membrane by activated Gαo-AlF4(-). Bioluminescence resonance energy transfer studies showed that RGS14 adopts different conformations in live cells when bound to Gα in different activation states. Hydrogen/deuterium exchange mass spectrometry revealed that RGS14 is a very dynamic protein that undergoes allosteric conformational changes when inactive Gαi1-GDP binds the GPR motif. Pure RGS14 forms a ternary complex with Gαo-AlF4(-) and an AlF4(-)-insensitive mutant (G42R) of Gαi1-GDP, as observed by size exclusion chromatography and differential hydrogen/deuterium exchange. Finally, a preformed RGS14·Gαi1-GDP complex exhibits full capacity to stimulate the GTPase activity of Gαo-GTP, demonstrating that RGS14 can functionally engage two distinct forms of Gα subunits simultaneously. Based on these findings, we propose a working model for how RGS14 integrates multiple G protein signals in host CA2 hippocampal neurons to modulate synaptic plasticity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

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

International Nuclear Information System (INIS)

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

1987-01-01

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

Optimization of Sealed Tube Graphitization Method for Environmental C-14 Studies Using MICADAS

Energy Technology Data Exchange (ETDEWEB)

Rinyu, Laszlo, E-mail: rinyu@atomki.hu [Hertelendi Laboratory of Environmental Studies, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen (Hungary); Isotoptech Zrt., H-4025 Debrecen (Hungary); Molnar, Mihaly [Hertelendi Laboratory of Environmental Studies, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen (Hungary); Ion Beam Physics, ETH Zuerich, CH-8093 Zuerich (Switzerland); Major, Istvan [Hertelendi Laboratory of Environmental Studies, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen (Hungary); Nagy, Tamas; Veres, Mihaly [Isotoptech Zrt., H-4025 Debrecen (Hungary); Kimak, Adam [University of Debrecen, H-4032 Debrecen (Hungary); Wacker, Lukas; Synal, Hans-Arno [Ion Beam Physics, ETH Zuerich, CH-8093 Zuerich (Switzerland)

2013-01-15

The original sealed tube zinc reduction graphitization process was first developed for rapid low-precision measurements of biomedical tracer samples and later also applied for high precision measurements of not too old samples. In this study we tested the MICADAS (mini radiocarbon dating system [1]) radiocarbon measurements of targets prepared by sealed tube graphitization process. We found the optimal iron catalyst and reagents (TiH{sub 2} and Zn) amount whereby we can reach a relatively low background level, and minimized the overall {delta}{sup 13}C fractionation during the graphitization. Repeated measurements of normalization standards and real samples with known {sup 14}C activities were very well reproduced. Finally, we demonstrated the applicability of the sealed tube graphitization on real environmental samples covering a wide range of {sup 14}C concentrations.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-10-15

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

Synthesis of (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolic acid, methyl (1'-/sup 13/C)olivetolate and (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolic acid

Energy Technology Data Exchange (ETDEWEB)

Porwoll, J P; Leete, E [Minnesota Univ., Minneapolis (USA). Dept. of Chemistry

1985-03-01

Potential advanced intermediates in the biosynthesis of delta/sup 9/-tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous /sup 13/C atoms and /sup 14/C. Methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolate was prepared from lithium (/sup 13/C/sub 2/)acetylide and dimethyl (2-/sup 14/C)malonate. Reaction with geranyl bromide afforded methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The /sup 13/C-/sup 13/C couplings observable in the /sup 13/C NMR spectra of these /sup 13/C-enriched compounds and their synthetic precursors are recorded. Methyl (1'-/sup 14/C)olivetolate was prepared from /sup 13/CO/sub 2/ to confirm assignments of the /sup 13/C chemical shifts in the pentyl side chain of these compounds.

European dendrochronoloy and C-14 dating of timber

International Nuclear Information System (INIS)

Fletcher, J.M.

1975-01-01

An account is given of the development of dendrochronology and C-14 dating in Europe. Corrections to raw C-14 dates, sampling and the uncertainty of C-14 ages of wood, and correlation of dates obtained by the two methods, are discussed. (U.K.)

Synthesis of 14C-labeled stepholidine

International Nuclear Information System (INIS)

Yang Liu; Zhang Xin

1988-01-01

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

Anthropogenic 14C in the natural (aquatic) environment

International Nuclear Information System (INIS)

Begg, F.H.

1992-11-01

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

Synthesis of /sup 14/C-labelled milrinone

Energy Technology Data Exchange (ETDEWEB)

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

1985-02-01

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

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

International Nuclear Information System (INIS)

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

1983-01-01

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

Nuclear reactions with 11C and 14O radioactive ion beams

International Nuclear Information System (INIS)

Guo, Fanqing

2004-01-01

Radioactive ion beams (RIBs) have been shown to be a useful tool for studying proton-rich nuclides near and beyond the proton dripline and for evaluating nuclear models. To take full advantage of RIBs, Elastic Resonance Scattering in Inverse Kinematics with Thick Targets (ERSIKTT), has proven to be a reliable experimental tool for investigations of proton unbound nuclei. Following several years of effort, Berkeley Experiments with Accelerated Radioactive Species (BEARS), a RIBs capability, has been developed at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. The current BEARS provides two RIBs: a 11C beam of up to 2x108 pps intensity on target and an 14O beam of up to 3x104 pps intensity. While the development of the 11C beam has been relatively easy, a number of challenges had to be overcome to obtain the 14O beam. The excellent 11C beam has been used to investigate several reactions. The first was the 197Au(11C,xn)208-xnAt reaction, which was used to measure excitation functions for the 4n to 8n exit channels. The measured cross sections were generally predicted quite well using the fusion-evaporation code HIVAP. Possible errors in the branching ratios of ?? decays from At isotopes as well as the presence of incomplete fusion reactions probably contribute to specific overpredictions. 15F has been investigated by the p(14O,p)14O reaction with the ERSIKTT technology. Several 14O+p runs have been performed. Excellent energy calibration was obtained using resonances from the p(14N,p)14N reaction in inverse kinematics, and comparing the results to those obtained earlier with normal kinematics. The differences between 14N+p and 14O+p in the stopping power function have been evaluated for better energy calibration. After careful calibration, the energy levels of 15F were fitted with an R-matrix calculation. Spins and parities were assigned to the two observed resonances. This new measurement of the 15F ground state supports the disappearance of the Z = 8

Structure of 14C and 14B from the C,1514(d ,3He)B,1413 reactions

Science.gov (United States)

Bedoor, S.; Wuosmaa, A. H.; Albers, M.; Alcorta, M.; Almaraz-Calderon, Sergio; Back, B. B.; Bertone, P. F.; Deibel, C. M.; Hoffman, C. R.; Lighthall, J. C.; Marley, S. T.; Mcneel, D. G.; Pardo, R. C.; Rehm, K. E.; Schiffer, J. P.; Shetty, D. V.

2016-04-01

We have studied the C,1514(d ,3He)B,1413 proton-removing reactions in inverse kinematics. The (d ,3He ) reaction probes the proton occupation of the target ground state, and also provides spectroscopic information about the final states in B,1413. The experiments were performed using C,1514 beams from the ATLAS accelerator at Argonne National Laboratory. The reaction products were analyzed with the HELIOS device. Angular distributions were obtained for transitions from both reactions. The 14C-beam data reveal transitions to excited states in 13B that suggest configurations with protons outside the π (0 p3 /2) orbital, and some possibility of proton cross-shell 0 p -1 s 0 d excitations, in the 14C ground state. The 15C-beam data confirm the existence of a broad 2- excited state in 14B. The experimental data are compared to the results of shell-model calculations.

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

International Nuclear Information System (INIS)

Iimura, Youichi; Mishima, Mannen; Sugimoto, Hachiro

1989-01-01

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

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

International Nuclear Information System (INIS)

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

1976-01-01

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

Calibration of 14C Histograms : A Comparison of Methods

NARCIS (Netherlands)

Stolk, Ad; Törnqvist, Torbjörn E.; Hekhuis, Kilian P.V.; Berendsen, Henk J.A.; Plicht, Johannes van der

1994-01-01

The interpretation of C-14 histograms is complicated by the non-linearity of the C-14 time scale in terms of Calendar years, which may result in clustering of C-14 ages in certain time intervals unrelated to the (geologic or archaeologic) phenomenon of interest. One can calibrate C-14 histograms for

10Be and 14C in the Earth system

International Nuclear Information System (INIS)

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

1987-01-01

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

Temporal variations in C-13 and C-14 concentrations in particulate organic matter from the southern North Sea

NARCIS (Netherlands)

Megens, L.; Plicht, J. van der; Leeuw, J.W. de

As a new approach for the characterization and determination of the origin of particulate organic matter (POM) in coastal waters, we measured the 14C activity and 13C/12C isotope ratios and applied molecular analysis by means of AMS, IRMS and pyrolysis-GCMS for both bulk samples and isolated

Formation and bio release of bound residues of [14 C]-lindane and [14 C]-parathion in two Brazilian soils

International Nuclear Information System (INIS)

Andrea, M.M. de.

1992-01-01

This work studied the extractable and bound residues formation of 14 C-lindane and 14 C-parathion immediately after application and after 3 months of interaction of the pesticides with the soils. Metabolism, bio release, and the possible bioavailability of bound residues were studied by employing bio meter flasks which allowed a relative comparison of the behaviour of the two different 14 C-pesticides, by a balance of the applied or present radiocarbon in the soils after the bio tests. (author)

Synthesis of (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolic acid, methyl (1'-/sup 13/C)olivetolate and (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolic acid

Energy Technology Data Exchange (ETDEWEB)

Porwoll, J.P.; Leete, E. (Minnesota Univ., Minneapolis (USA). Dept. of Chemistry)

1985-03-01

Potential advanced intermediates in the biosynthesis of delta/sup 9/-tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous /sup 13/C atoms and /sup 14/C. Methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolate was prepared from lithium (/sup 13/C/sub 2/)acetylide and dimethyl (2-/sup 14/C)malonate. Reaction with geranyl bromide afforded methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The /sup 13/C-/sup 13/C couplings observable in the /sup 13/C NMR spectra of these /sup 13/C-enriched compounds and their synthetic precursors are recorded. Methyl (1'-/sup 14/C)olivetolate was prepared from /sup 13/CO/sub 2/ to confirm assignments of the /sup 13/C chemical shifts in the pentyl side chain of these compounds.

The study of variations and environmental applications "1"4C

International Nuclear Information System (INIS)

Simon, J.

2010-01-01

The primary aim of the presented thesis is to explain experimentally observed "1"4C variations in the outer atmosphere. Physical models have been developed to quantify directly immeasurable phenomena relevant in the field of radiocarbon dynamics. Namely atmospheric stability, "1"4C transport from the stratosphere to the lower troposphere and fossil carbon dioxide emissions to the atmosphere. Finally these models have been used as the pillars of the united theory of Δ"1"4C dynamics. Besides the presented main theoretical outputs, this thesis also provides couple of potentially implementable by-products. First of them is a method to evaluate so called 'equivalent mixing height' and turbulent diffusion coefficient using temporal changes of "2"2"2Rn concentration in the boundary layer of the atmosphere. The elaborated mathematical apparatus for the evaluation of aerosol scavenging by raindrops can be utilized in the models of pollutant dispersion. Information on turbulent diffusion coefficient at higher atmospheric levels is important for the models of stratospheric and ozonospheric dynamics. Nowadays, when one can measure and even feel the greenhouse effect consequences, the importance of an independent method for carbon dioxide fossil emissions assessment is obvious. Besides theoretical outcome, the thesis also presents experimental results. A network of CO_2 sampling sites has been established in Bratislava and the outskirts in the vicinity of the town. Together with mountain site Chopok the network brought a unique information on "1"4C distribution. Atmospheric measurements of "7Be and "2"2"2Rn activity are also presented here. Finally the PC codes have been developed to bridge a gap between experimental and theoretical results. (author)

Persistence and fate of soil applied 14C-lindane in a maize ecosystem

International Nuclear Information System (INIS)

Yeboah, P.O.; Montford, K.G.; Apoh, W.; Dodoo, S.

1997-01-01

14 C-lindane applied to soil surface in a maize ecosystem (one month after planting) was taken up by the plant. Within the first 25 days of treatment, 14 C-lindane or its metabolites were found within the entire plant with the greatest concentration in lower leaves (from the ground level); and a sharp build up of lindane concentration towards the tip of each leaf. Radioactivity and hence pesticide concentration was uniformly distributed in the plant with time; to the extent that measurable levels of 14 C-compounds were detected in the tussel cob and the grain. This indicated that soil applied lindane was available to the maize plant. The persistence of 14 C-lindane in soils of variable organic matter content was also studied. Evidence is presented to show that 14 C-lindane dissipated faster in soils of lower organic matter content. Levels of surface applied pesticides that became bound in the soil increased with time after application and also with increasing organic matter content. 14 C-activity was mainly associated with the top soil layer (0-30 mm). (author). 7 refs, 7 figs

Precision Measurement of the e+e-→Λc+Λ¯c - Cross Section Near Threshold

Science.gov (United States)

Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Bai, Y.; Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Begzsuren, K.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chai, J.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, P. L.; Chen, S. J.; Chen, X. R.; Chen, Y. B.; Chu, X. K.; Cibinetto, G.; Cossio, F.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; de Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fang, J.; Fang, S. S.; Fang, Y.; Farinelli, R.; Fava, L.; Fegan, S.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, Y.; Gao, Y. G.; Gao, Z.; Garillon, B.; Garzia, I.; Gilman, A.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guo, A. Q.; Guo, R. P.; Guo, Y. P.; Guskov, A.; Haddadi, Z.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, X. Q.; Heinsius, F. H.; Held, T.; Heng, Y. K.; Holtmann, T.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Z. L.; Hussain, T.; Ikegami Andersson, W.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jin, Y.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Khan, T.; Khoukaz, A.; Kiese, P.; Kliemt, R.; Koch, L.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kuemmel, M.; Kuhlmann, M.; Kupsc, A.; Kühn, W.; Lange, J. S.; Lara, M.; Larin, P.; Lavezzi, L.; Leithoff, H.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, J. W.; Li, Jin; Li, K. J.; Li, Kang; Li, Ke; Li, Lei; Li, P. L.; Li, P. R.; Li, Q. Y.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Libby, J.; Lin, C. X.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. L.; Liu, H. M.; Liu, Huanhuan; Liu, Huihui; Liu, J. B.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, Ke; Liu, L. D.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Long, Y. F.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, X. L.; Lusso, S.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Meng, Z. X.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Muchnoi, N. Yu.; Muramatsu, H.; Mustafa, A.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Papenbrock, M.; Patteri, P.; Pelizaeus, M.; Pellegrino, J.; Peng, H. P.; Peng, Z. Y.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Pitka, A.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qi, T. Y.; Qian, S.; Qiao, C. F.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Richter, M.; Ripka, M.; Rolo, M.; Rong, G.; Rosner, Ch.; Sarantsev, A.; Savrié, M.; Schnier, C.; Schoenning, K.; Shan, W.; Shan, X. Y.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shi, X.; Song, J. J.; Song, W. M.; Song, X. Y.; Sosio, S.; Sowa, C.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, L.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. K.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tan, Y. T.; Tang, C. J.; Tang, G. Y.; Tang, X.; Tapan, I.; Tiemens, M.; Tsednee, B.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, Dan; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, Meng; Wang, P.; Wang, P. L.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wang, Zongyuan; Weber, T.; Wei, D. H.; Wei, J. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, Y.; Xiao, D.; Xiao, Y. J.; Xiao, Z. J.; Xie, Y. G.; Xie, Y. H.; Xiong, X. A.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, F.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. H.; Yang, Y. X.; Yang, Yifan; Ye, M.; Ye, M. H.; Yin, J. H.; You, Z. Y.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. T.; Zhang, Yang; Zhang, Yao; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, Q.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, A. N.; Zhu, J.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; Besiii Collaboration

2018-03-01

The cross section of the e+e-→Λc+Λ¯c - process is measured with unprecedented precision using data collected with the BESIII detector at √{s }=4574.5 , 4580.0, 4590.0 and 4599.5 MeV. The nonzero cross section near the Λc+Λ¯c- production threshold is cleared. At center-of-mass energies √{s }=4574.5 and 4599.5 MeV, the higher statistics data enable us to measure the Λc polar angle distributions. From these, the Λc electric over magnetic form-factor ratios (|GE/GM|) are measured for the first time. They are found to be 1.14 ±0.14 ±0.07 and 1.23 ±0.05 ±0.03 , respectively, where the first uncertainties are statistical and the second are systematic.

Clinical investigation of 14C-urea breath test

International Nuclear Information System (INIS)

Yu Yongli; Zhu Ruisen; Ji Hong; Luo Quanyong

2000-01-01

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

C-14 measurements in organic sediments

International Nuclear Information System (INIS)

Vagner, Irina; Varlam, Carmen; Stefanescu, Ioan; Faurescu, Ionut; Bogdan, Diana; Faurescu, Denisa; Cuna, Stela

2009-01-01

Full text: The CO 2 direct absorption method of preparing samples for radiocarbon analysis by liquid scintillation counting has been successfully applied in many laboratories primarily for 'dating' the groundwater. Even if the method follows the similar principle as by the benzene synthesis method, time less consuming by the direct absorption method is a strong motivation enhancing the type of samples that can be prepared by this method. The samples used to settle the procedure were various types of soil and slurry from the bottom sediments in rivers and lakes. The carbon occurring in those samples can be inorganic or organic carbon. Inorganic carbon can be analyzed by direct absorption method rather easy by sample acidification and CO 2 capture. In this work it has been investigated a hybrid method that connects the wet oxidation of organic carbon with direct absorption method. The wet oxidation with potassium dichromate 1N solution, in presence of concentrated sulphuric acid and silver sulphate was applied to samples, prior acidification to release inorganic carbon as CO 2 . To overcome the concern of incomplete digestion of organic matter, the procedure was conducted by extensive heating of the sample during wet oxidation process. Possibilities of occurrence of isotopic fractionation during CO 2 production from raw material were investigated by measuring δ 13 C from sample and the CO 2 obtained. Special attention was paid to sample preparation technique and the 'direct absorption method' has been used with few 'home-made' improvements in order to increase the reproducibility and accuracy of this simple and less-time consuming method. (authors)

Fate and bioavailability of 14C-pyrene and 14C-lindane in sterile natural and artificial soils and the influence of aging

International Nuclear Information System (INIS)

Šmídová, Klára; Hofman, Jakub; Ite, Aniefiok E.; Semple, Kirk T.

2012-01-01

Soil organic matter is used to extrapolate the toxicity and bioavailability of organic pollutants between different soils. However, it has been shown that other factors such as microbial activity are crucial. The aim of this study was to investigate if sterilization can reduce differences in the fate and bioavailability of organic pollutants between different soils. Three natural soils with increasing total organic carbon (TOC) content were collected and three artificial soils were prepared to obtain similar TOCs. Soils were sterilized and spiked with 14 C-pyrene and 14 C-lindane. Total 14 C radioactivity, HPCD extractability, and bioaccumulation in Eisenia fetida were measured over 56 days. When compared to non-sterile soils, differences between the natural and artificial soils and the influence of soil-contaminant contact time were generally reduced in the sterile soils (especially with middle TOC). The results indicate the possibility of using sterile soils as “the worst case scenario” in soil ecotoxicity studies. - Highlights: ► Sterile artificial and natural soils with the same TOC content were used. ► The fate and behavior of two 14 C-POPs were studied over 56 days after spiking. ► Sterilization reduced differences between artificial and natural soils. ► There was no effect of time (aging) in POPs bioaccumulation. ► Sterile soils may be used as “the worst case scenario” in POPs availability studies. - Sterilization reduced the differences in POPs fate and bioavailability between artificial and natural soils with the same TOC content and eliminated the influence of soil contact time.

Distribution and utilization of 14C-labelled assimilate in debranched soybeans

International Nuclear Information System (INIS)

Kokubun, Makie; Asahi, Yukimitsu

1985-01-01

Effects of debranching of soybean plants on the distribution and utilization of 14 C assimilate were studied. Leaves at different positions in the canopy were allowed to assimilate 14 CO 2 either at early flowering, at early pod growth, or at early pod-filling stage. Radioactivity at 24 hours or 7 days after labelling was measured in the component parts. Debranching increased the dry weight of the main stem resulting from greater increase at the lower section of the stem. The debranched plants had the leaves of higher assimilatory efficiency and delayed senescence. The leaves at lower position of the debranched plants exported 14 C less at flowering but more at early pod growth than those of controls. When 14 C was incorporated from upper leaves, the difference in the distribution pattern between the debranched and control plants was little. A greater portion of 14 C assimilate fixed at the lower leaves of the debranched plants was present at pods and stem + petioles of the lower section, in contrast to those of controls which exported some of the assimilate to the branches. Lower leaves of the debranched plants remained active even during pod growth stage, and a part of the fixed 14 C was translocated slowly into the root. The pattern of distribution and utilization of assimilate in debranched soybeans may account for the adaptability of the main stem type to higher planting density. (author)

Penetrative and dislodgeable residue characteristics of 14C-insecticides in apple fruit.

Science.gov (United States)

Mota-Sanchez, David; Cregg, Bert; Hoffmann, Eric; Flore, James; Wise, John C

2012-03-28

Infinite- and finite-dose laboratory experiments were used to study the penetrative and dislodgeable residue characteristics of (14)C-insecticides in apple fruit. The differences in dislodgeable and penetrated residues of three radiolabeled insecticides ((14)C-thiamethoxam, (14)C-thiacloprid, and (14)C-indoxacarb), applied in aqueous solution with commercial formulations, were determined after water and methanol wash extractions. The rate of sorption and extent of penetration into the fruit cuticles and hypanthium of two apple cultivars were measured after 1, 6, and 24 h of treatment exposure, using radioactivity quantification methods. For all three compounds, 97% or more of the treatment solutions were found on the fruit surface as some form of non-sorbed residues. For indoxacarb, sorption into the epicuticle was rapid but desorption into the fruit hypanthium was delayed, indicative of a lipophilic penetration pathway. For the neonicotinoids, initial cuticular penetration was slower but with no such delay in desorption into the hypanthium.

Differential blood-brain barrier permeabilities to [14C]sucrose and [3H]inulin after osmotic opening in the rat

International Nuclear Information System (INIS)

Ziylan, Y.Z.; Robinson, P.J.; Rapoport, S.I.

1983-01-01

The blood-brain barrier (B-BB) in 3-month-old rats was opened unilaterally by infusing 1.8 m L(+)arabinose in water into the internal carotid artery through a catheter in the external carotid. Two poorly penetrating uncharged test radiotracers of differing molecular weight and size, [ 14 C]sucrose (340 daltons, radius 5 A) and [ 3 H]inulin (5500 daltons, radius 15 A), were simultaneously injected i.v. in untreated rats, or rats at 1, 30, or 50 min after infusion of hypertonic arabinose solution. Evans-blue solution was injected 5 min prior to osmotic treatment as a visual indicator of barrier integrity. In regions of uninfused control brains, the [ 14 C]sucrose permeability-surface area (PA) product approximated 10(-5) s-1, whereas PA was not measurable for [ 3 H]inulin. In arabinose-infused animals, PA products on the ipsilateral hemisphere for both [ 14 C]sucrose and [ 3 H]inulin were markedly elevated 6 min after infusion, but decreased by 35 and 55 min. In nearly all regions, statistically significant differences were not found between 6-min [ 14 C]sucrose- and [ 3 H]inulin-PA values (P greater than 0.05). However, at 35 and 55 min in most regions, the PA for [ 3 H]inulin was significantly lower (P less than 0.05) than PA for [ 14 C]sucrose. The results indicated that the B-BB closed more rapidly to larger than to smaller molecules after osmotic treatment and were consistent with a pore model for osmotic B-BB opening

Fate of 14C-labelled compounds in marine environment

International Nuclear Information System (INIS)

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

1999-01-01

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

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

Directory of Open Access Journals (Sweden)

Chałupnik Stanisław

2014-03-01

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

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

International Nuclear Information System (INIS)

Stuiver, M.; Quay, P.D.

1981-01-01

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

Radioactive waste with 14C in Argentina

International Nuclear Information System (INIS)

Di Lello, D.S.

2009-01-01

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

Dermal absorption and distribution of 14 C carbaryl in wistar rats

International Nuclear Information System (INIS)

Tos-Luty, S.; Tokarska-Rodak, M.; Latuszynska, J.; Przebirowska, D.

2001-01-01

The level of 14 C carbaryl was determined in blood (leukocytes, erythrocytes, all blood cells, plasma) and organs (brain, heart, lungs, liver, spleen, skin at the site of exposure) of male Wistar rats after dermal administration. The application liquid was 14 C carbaryl solution in 96% ethyl alcohol. This preparation, possessing an activity of 670 kBq/ml, containing 1.67 mg of carbaryl, was applied to the skin of the tail according to Massmann's method in own modification. The amount of the preparation per 1 cm 2 of the tail skin was 0.19 mg of carbaryl (74.4 kBq). The tails of experimental rats were exposed to 14 C carbaryl by soaking for 4 h daily: once, twice or three times. Beta radiation from 14 C was measured in homogenized organs (brain, heart, lungs, liver, skin) and in blood by computer controlled Wallac scintillation counter Model 1409, using Multi Calc software. The dermal absorption of carbaryl at the site of exposure and in the surrounding area of about 2 cm was observed already during 4 hour exposure. Carbaryl reached plasma within 4 h of a single dermal exposure and penetrated into leukocytes, erythrocytes, heart, liver, lung, kidney and brain. The largest amount of 14 C carbaryl, about 2% of absorbed dose, was detected in liver. (author)

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

International Nuclear Information System (INIS)

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

1989-01-01

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

Carbon-14 measurements and characterization of dissolved organic carbon in ground water

International Nuclear Information System (INIS)

Murphy, E.M.

1987-01-01

Carbon-14 was measured in the dissolved organic carbon (DOC) in ground water and compared with 14 C analyses of dissolved inorganic carbon (DIC). Two field sites were used for this study; the Stripa mine in central Sweden, and the Milk River Aquifer in southern Alberta, Canada. The Stripa mine consists of a Precambrian granite dominated by fracture flow, while the Milk River Aquifer is a Cretaceous sandstone aquifer characterized by porous flow. At both field sites, 14 C analyses of the DOC provide additional information on the ground-water age. Carbon-14 was measured on both the hydrophobic and hydrophilic organic fractions of the DOC. The organic compounds in the hydrophobic and hydrophilic fractions were also characterized. The DOC may originate from kerogen in the aquifer matrix, from soil organic matter in the recharge zone, of from a combination of these two sources. Carbon-14 analyses, along with characterization of the organics, were used to determine this origin. Carbon-14 analyses of the hydrophobic fraction in the Milk River Aquifer suggest a soil origin, while 14 C analyses of the hydrophilic fraction suggest an origin within the Cretaceous sediments (kerogen) or from the shale in contact with the aquifer

14C/C measurements support Andreev's internode method to determine lichen growth rates in Cladina stygia (Fr.) Ahti

Energy Technology Data Exchange (ETDEWEB)

Holt, E; Bench, G

2007-12-05

Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, Andreev proposed a method to date Cladina, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of {sup 14}C/C ratios to determine lichen age and growth rate in Cladina stygia (Fr.) Ahti collected from northwestern Alaska, USA. The average growth rate using {sup 14}C/C ratios was 6.5 mm {center_dot} yr{sup -1}, which was not significantly different from growth rates derived by Andreev's internode method (average = 6.2 mm {center_dot} yr{sup -1}); thus, suggesting the reliability of Andreev's simple field method for dating lichens. In addition, we found lichen growth rates appeared to differ with geographic location, yet did not seem related to ambient temperature and total precipitation.

Studies on dissipation and degradation of 14 C-DDT and 14 C-parathion in egyptian soil under field conditions

International Nuclear Information System (INIS)

Ezz El-Arab, A.; Mostafa, I.Y.

1991-01-01

The rates of dissipation and degradation of the insecticides DDT and parathion were studied under field conditionsm using 14 C-labelled chemicals. Over a period of 12 weeks, extractable, soil-bound and total 14 C-activity were recorded. In case of DDT, dissipation of 14 C-activity from soil showed a continuous and gradual increase reaching about 30% after 8 weeks and remained constant up to 12 weeks. The formation of DDE as a principal metabolite seems to be increasing with time ans accounted for approximately 25% of the extractable residues after 12 weeks. There was also a gradual significant increase in the formation of soil 14 C-bound residues which reached 12% of the total residues after the same period. On the other hand, parathion dissipation from the soil under the same conditions did not exceed 10% up to 12 weeks. The amount of 14 C-bound residues was found to contribute 33% of the applied dose. Analysis of the extractable fraction revealed that parathion was partly degraded by soil microorganisms into p-amino phenol, p-nitrophenol, paraoxon, amino parathion and aminoparaoxon in different percentages depending on the depth of soil. 2 fig.,1 tab

14C Carbofuran residue in rice-fish ecosystem model

International Nuclear Information System (INIS)

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

1988-01-01

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

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

International Nuclear Information System (INIS)

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

1999-01-01

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

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

International Nuclear Information System (INIS)

Dickinson, J.R.

1985-01-01

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

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

International Nuclear Information System (INIS)

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

1983-01-01

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

Magnitude of 14C/12C variations based on archaeological samples

International Nuclear Information System (INIS)

Kusumgar, S.; Agrawal, D.P.

1977-01-01

The magnitude of 14 C/ 12 C variations in the period A.D. 5O0 to 200 B.C. and 370 B.C. to 2900 B.C. is discussed. The 14 C dates of well-dated archaeological samples from India and Egypt do not show any significant divergence from the historical ages. On the other hand, the corrections based on dendrochronological samples show marked deviations for the same time period. A plea is, therefore, made to study old tree samples from Anatolia and Irish bogs and archaeological samples from west Asia to arrive at a more realistic calibration curve. (author)

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

Science.gov (United States)

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

2018-06-25

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

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

International Nuclear Information System (INIS)

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

1990-01-01

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

Atmospheric nuclear weapon test history as characterized by the deposition of 14C in human teeth

International Nuclear Information System (INIS)

Nishizawa, K.; Togari, A.; Matsumoto, S.; Nagatsu, T.

1990-01-01

The 14 C concentration in the collagen of human teeth was retrospectively investigated to determine whether its incorporation was related to atmospheric testing of nuclear weapons. Teeth were extracted for dental therapy from July 1987 to February 1988 from patients who were residents in Japan. Tooth collagen was extracted with HCl and converted to amorphous C by heating in a vacuum line. Specimens for 14 C analysis were prepared by mixing the amorphous C with silver powder. The 14 C concentration was measured by mass spectrometer. The 14 C concentration in tooth collagen rapidly increased in 1961 after the bomb tests, peaked around 1967-1968, and then gradually decreased. The collagen of human teeth maintains the 14 C concentration at the age of root completion for life. The results of this study indicate that the history of environmental contamination from atmospheric nuclear weapon's tests has been characterized by deposition of 14 C in the tooth collagen 14 C of human beings

Bioconcentration of 14 C-Carbofuran and 14 C- Lindane in fresh water Tilapia Nilitica and the bioavailability of their residues to rats

International Nuclear Information System (INIS)

Aly, M.A.S.; Afifi, L.M.

1997-01-01

Tilapia Nilotica were exposed to 14 C- carbofuran (125 MUg/1) and 14 C - lindane (80 MUg/1) for 96 h. Uptake period followed by 8 days depuration period. The bioconcentration factor (BCF) for carbofuran reached 32.4 at 12 h and 82 for lindane at 48 h. The amount of 14 C-activity found in fish treated with 14 C - carbofuran after the uptake period showed the following descending order: viscera > remaining parts > gills > muscles. In case of 14 C - lindane treated fish the recovered amount followed the order; remaining parts> viscera > gills muscles. During the depuration period, carbofuran residues taken up by fish were eliminated in 2 phases, an initial rapid phase followed by a slower gradual one. However, the rate of elimination in case of lindane was much slower especially during the first 2 days. At the end of the depuration period (8 days), the muscles (edible portion) contained 10% and 58% of 14 C -activity in case of carbofuran and lindane treated groups, respectively. Both insecticides proved to be bioavailable when rats were fed treated fish. Of the administered dose, 44.1% and 53.0% were excreted in urine and feces case of 14 C-carbofuran while in case of 14 C - lindane it was 30.9% and 41.7% for urine and feces, respectively. 2 figs., 2 tabs

Biodegradation mechanism of linear alkylbenzenesulfonate-14C

International Nuclear Information System (INIS)

Kubodera, Tadayoshi; Muto, Toshio; Yamamoto, Tatsuo

1978-01-01

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

Synthesis of {sup 14}C-labeled levamisole and {sup 13}C-labeled tetramisole

Energy Technology Data Exchange (ETDEWEB)

Feil, V.J. [US Department of Agriculture, Agricultural Research Service, Biosciences Research Lab., Fargo, ND (United States)

1996-12-01

The syntheses of {sup 14}C-ring labeled levamisole ([-]-2,3,5,6-tetrahydro-6-phenyl [{sup 14}C]-UL imidazo[2,1-b]thiazole) from acetophenone-ring-UL-{sup 14}C in 5 steps plus resolution with a 7.5% overall yield, and {sup 13}C{sub 6}-ring labeled tetramisole ([{+-}]-2,3,5,6-tetrahydro-6-phenyl [{sup 13}C{sub 6}]imidazo[2,1-b]thiazole) from benzene-{sup 13}C{sub 6} in 6 steps with a 9.0% overall yield are described. (author).

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

International Nuclear Information System (INIS)

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

1988-01-01

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

The uptake of 14C-glycine to Bufo vulgaris formosus (Boulenger) larva at metamorphosis

International Nuclear Information System (INIS)

Hasegawa, Hitoshi; Tanaka, Haruo; Ishiguro, Shigeru; Nonoyama, Kiyoshi; Nakagawa, Harumi.

1981-01-01

With the eggs of Bufo vulgaris formosus (Boulenger) immediately after fertilization, the larvae in the 50 ml solution containing 1 ml of 14 C-glycine were developed to the end of metamorphosis. Measurements were made on the length of body, tail, fore limb and hind leg through the stages of tail degeneration and vestige. The radioactivity of the cut off fore limbs, hind legs, tails and head trunks was measured with a scintillation counter, and the 10 μ sections of the samples were used for autoradiography. The larvae uptook orally 14 C-glycine to the organs of cell tissues. On the basis of the reports of the autolysis of tails and the activation of lysosome enzyme in metamorphosis and on the uptake of 14 C-leucine and 14 C-proline to four legs by other workers, and on the present results, the free amino acids formed from the autolysis of tails were utilized for the recomposition of organ protein synthesis in the metamorphosis of the amphibians. (J.P.N.)

Permeability of ferret trachea in vitro to 99m Tc-DTPA and [14C]antipyrine

International Nuclear Information System (INIS)

Hanafi, Z.; Webber, S.E.; Widdicombe, J.G.

1994-01-01

Platelet-activating factor (PAF) and vasoactive drugs were tested on permeability of ferret trachea in vitro by measuring fluxes of 99m T c -diethylenetriamine pentaacetic acid ( 99m T c -DTPA; hydrophilic) and [ 14 C]antipyrine ([ 14 C]AP; lipophilic) across the tracheal wall. Tracheae were bathed on both sides with Krebs-Henseleit buffer, with luminal buffer containing either 99m T c -DTPA or [ 14 C]AP. Luminal and abluminal radioactivities, potential difference, and tracheal smooth muscle tone were measured. Baseline 99m T c -DTPA and [ 14 C]AP permeability coefficients were - 4.7 ± 0.6 (SE) x 10 -7 and -2.2 ± 0.1 x 10 -5 cm/s, respectively. PAF (10 μM) increased permeability to 99m T c -DTPA to -35.3 ± 7.6 x 10 -7 cm/s (P 14 C]AP did not change, suggesting that paracellular but not transcellular transport was affected. Abluminal and luminal applications of methacholine (MCh, 20 μM), phenylephrine (PE, 100 μM), and albuterol (Alb, 100 μM) caused no change in permeability to 99m T c -DTPA before or after exposure to luminal PAF, but abluminal histamine (Hist, 10 μM) significantly increased permeability. Abluminal Hist decreased permeability to [ 14 C]AP before and after exposure to PAF. MCh, PE, and Hist increased smooth muscle tone; Alb and PAF had no effect. Thus, only PAF and Hist altered permeability to 99m T c -DTPA, and MCh, PE, and Hist changed smooth muscle tone. Tracheal permeability changes were greater for the hydrophilic than for the lipophilic agent. 37 refs., 11 figs., 1 tab

C14 Assays and Autoradiographic Studies on the Rooster Comb

Science.gov (United States)

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

1959-01-01

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

Organic compounds preparation with 14 C

International Nuclear Information System (INIS)

Shirvani, Gholam Hossein.

1996-09-01

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

Leaching of 14C and 36Cl from irradiated French graphite

International Nuclear Information System (INIS)

Gray, W.J.; Morgan, W.C.

1989-08-01

The leach rates of 14 C and 36 Cl were measured on solid cylindrical samples prepared from irradiated graphite blocks supplied by the French Commissariat a l'Energie Atomique (CEA). Static leach tests were conducted in deionized water at 20 degree C for 13 weeks. The graphite samples were completely submerged in the water, and the entire volume of water was changed and analyzed at weekly intervals for the first three weeks and biweekly thereafter. Large differences in the leach rates of both 14 C and 36 Cl were observed between samples machined from the different blocks. In general, the leach rates were much higher than those measured in an earlier study with graphite obtained from a block removed from one of the Hanford reactors. The data from this study are compared with those from the previous study using the Hanford-reactor graphite. Implications of the data from both studies regarding possible rate-limiting mechanisms are discussed. 4 refs., 8 figs., 3 tabs

Initial Results of an Intercomparison of AMS-Based Atmospheric 14CO2 Measurements

NARCIS (Netherlands)

Miller, John; Lehman, Scott; Wolak, Chad; Turnbull, Jocelyn; Dunn, Gregory; Graven, Heather; Keeling, Ralph; Meijer, Harro A. J.; Aerts-Bijma, Anita Th; Palstra, Sanne W. L.; Smith, Andrew M.; Allison, Colin; Southon, John; Xu, Xiaomei; Nakazawa, Takakiyo; Aoki, Shuji; Nakamura, Toshio; Guilderson, Thomas; LaFranchi, Brian; Mukai, Hitoshi; Terao, Yukio; Uchida, Masao; Kondo, Miyuki

2013-01-01

This article presents results from the first 3 rounds of an international intercomparison of measurements of Delta(CO2)-C-14 in liter-scale samples of whole air by groups using accelerator mass spectrometry (AMS). The ultimate goal of the intercomparison is to allow the merging of Delta(CO2)-C-14

Measurement of the electron attachment rates for SF6 and C7F14 at Te=0.2 eV in a magnetized Q machine plasma

International Nuclear Information System (INIS)

Merlino, Robert L.; Kim, Su-Hyun

2008-01-01

Electron attachment rates for SF 6 and C 7 F 14 were measured in a magnetized Q machine plasma at an electron temperature of 0.2±0.02 eV and with neutral gas pressures of P∼10 -4 Torr. The rate constants for attachment to SF 6 and C 7 F 14 were (7.6±2.0)x10 -8 and (2.2±0.9)x10 -7 cm 3 s -1 , respectively.

Feasibility studies of RFQ based 14C accelerator mass spectrometry

International Nuclear Information System (INIS)

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

2007-01-01

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

Two-Pion Correlation Measurements for 14.6 A.GEV/C SILICON-28 + X and 11.6 A.GEV/C GOLD-197 + Gold.

Science.gov (United States)