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Sample records for protium

  1. Triterpenes from Protium hebetatum resin.

    PubMed

    Marques, Delcio Dias; Graebner, Ilmar Bernardo; de Lemos, Telma Leda Gomes; Machado, Luciana Lucas; Assunção, Jõao Carlos Costa; Monte, Francisco José Queiroz

    2010-08-01

    Three olean (beta-amyrenone, beta-amyrin and maniladiol), three ursane (alpha-amyrinone, alpha-amyrin and breine) and four tirucallane (3-oxotirucalla-8,24-dien-21-6ic acid, 3alpha-hydroxytirucalla-8,24-dien-21-oic acid, 3alpha-acetoxytirucalla-8,24-dien-21-oic acid and 3alpha-hydroxytirucalla-7,24-dien-21-oic acid) triterpenes were isolated from the oleoresin of Protium hebetatum Daly. The structures were established mainly by 13C, 1D and 2D NMR spectroscopic analysis. The isolation of 3alpha-hydroxytirucalla-8,24-dien-21-oic acid permitted correction of the chemical shift assignments of some of its carbon atoms. PMID:20839613

  2. Cryogenic distillation facility for isotopic purification of protium and deuterium

    NASA Astrophysics Data System (ADS)

    Alekseev, I.; Arkhipov, Ev.; Bondarenko, S.; Fedorchenko, O.; Ganzha, V.; Ivshin, K.; Kammel, P.; Kravtsov, P.; Petitjean, C.; Trofimov, V.; Vasilyev, A.; Vasyanina, T.; Vorobyov, A.; Vznuzdaev, M.

    2015-12-01

    Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

  3. Cryogenic distillation facility for isotopic purification of protium and deuterium

    SciTech Connect

    Alekseev, I.; Arkhipov, Ev.; Bondarenko, S.; Fedorchenko, O.; Ganzha, V.; Ivshin, K.; Kravtsov, P. Trofimov, V.; Vasilyev, A.; Vasyanina, T.; Vorobyov, A.; Vznuzdaev, M.; Kammel, P.; Petitjean, C.

    2015-12-15

    Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

  4. Inert blanketing of a hydride bed using typical grade protium

    SciTech Connect

    Klein, J.E.

    2015-03-15

    This paper describes the impact of 500 ppm (0.05%) impurities in protium on the absorption rate of a 9.66 kg LaNi{sub 4.25}Al{sub 0.75} (LANA0.75) metal hydride bed. The presence of 500 ppm or less inerts (i.e. non-hydrogen isotopes) can significantly impact hydrogen bed absorption rates. The impact on reducing absorption rates is significantly greater than predicted assuming uniform temperature, pressure, and compositions throughout the bed. Possible explanations are discussed. One possibility considered was the feed gas contained impurity levels higher than 500 ppm. It was shown that a level of 5000 ppm of inerts would have been necessary to fit the experimental result so this possibility wa dismissed. Another possibility is that the impurities in the protium supply reacted with the hydride material and partially poisoned the hydride. If the hydride were poisoned with CO or another impurity, the removal of the over-pressure gas in the bed would not be expected to allow the hydride loading of the bed to continue as the experimental results showed, so this possibility was also dismissed. The last possibility questions the validity of the calculations. It is assumed in all the calculations that the gas phase composition, temperature, and pressure are uniform throughout the bed. These assumptions are less valid for large beds where there can be large temperature, pressure, and composition gradients throughout the bed. Eventually the impact of 0.05% inerts in protium on bed absorption rate is shown and explained in terms of an increase in inert partial pressure as the bed was loaded.

  5. Anti-Inflammatory Activity of Triterpenes Isolated from Protium paniculatum Oil-Resins

    PubMed Central

    de Almeida, Patrícia D. O.; Boleti, Ana Paula de A.; Rüdiger, André Luis; Lourenço, Geane A.; da Veiga Junior, Valdir Florêncio; Lima, Emerson S.

    2015-01-01

    Protium is the main genus of the Burseraceae family and one of the most common genera in South America, with an important species called “breu.” Gum and oil-resins of this species are used as tonic and stimulant and for the treatment of ulcers and inflammation. The present study aims to isolate and investigate the anti-inflammatory activity of triterpene compounds isolated from oil-resin of Protium paniculatum. The pentacyclic triterpenes α,β-amyrin, acetylated α,β-amyrin, α,β-amyrone, and brein/maniladiol did not alter the viability of murine J774 macrophages (IC50 > 20 µg/mL), with the exception of mixture of brein/maniladiol which showed moderate cytotoxic activity. Also it was observed that compounds at 10 µg/mL inhibited more than 80% of production of NO•, although only α,β-amyrin was able to inhibit the production of TNF-α (52.03 ± 2.4%). The compounds inhibited the production of IL-6 and induced the production of IL-10 in murine J774 macrophages stimulated by LPS. α,β-Amyrone inhibited the expression of COX-2 and also inhibited the formation of paw or ear edema in rats and mice, having a quick and immediate effect. This study may provide the basis for future investigations on the therapeutic role of α,β-amyrone in treating inflammation. PMID:27034686

  6. A Low Temperature Distillation System for Separating Mixtures of Protium, Deuterium, and Tritium Isotopes

    SciTech Connect

    Embury, Michael, C.; Watkins, Reed A.; Hinckley, Richard; Post, Jr., Arthur H.

    1985-04-30

    A low temperature (24 K) distillation system for separating mixtures of hydrogen isotopes has been designed, fabricated, and delivered for use as the main component of the Hydrogen Isotope Separation System (HISS) at Mound. The HISS will handle feed mixtures of all six isotopic species of hydrogen (H2, HD, HT, D2, DT, T2) and will enrich the tritium while producing a stackable raffinate. Arther D. Little, Inc. (ADL) was the prime contractor for the distillation system. The design and fabrication techniques used for the HISS distillation system are similar to those used for previous stills which were also designed and built by ADL. The distillation system was tested with mixtures of protium and deuterium at the ADL shop. This system, as well as the feed, product, and raffinate handling systems are presently being installed at Mound where integrated testing is scheduled next calendar year.

  7. Essential Oil from the Resin of Protium heptaphyllum: Chemical Composition, Cytotoxicity, Antimicrobial Activity, and Antimutagenicity

    PubMed Central

    de Lima, Ewelyne Miranda; Cazelli, Didley Sâmia Paiva; Pinto, Fernanda Endringer; Mazuco, Renata Alves; Kalil, Ieda Carneiro; Lenz, Dominik; Scherer, Rodrigo; de Andrade, Tadeu Uggere; Endringer, Denise Coutinho

    2016-01-01

    Background: Protium heptaphyllum (Aubl.) March is popularly used as an analgesic and anti-inflammatory agent. Objective: This study aimed to evaluate the chemical composition of P. heptaphyllum essential oil, its cytotoxicity in a breast cancer cell line (MCF-7), antimicrobial activity, and its antimutagenicity in vivo. Materials and Methods: The chemical composition of the essential oil collected in three 3 years was determined by gas chromatography-mass spectrometry. The cytotoxicity was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Annexin V conjugated with fluorescein isothiocyanate, caspase-3, and tumor necrosis factor-alpha (TNF-α) assays were performed to evaluate apoptosis and inflammatory events. The antimutagenic activity at doses of 25, 50, and 100 mg/kg was determined using a micronucleus test in murine bone marrow. Results: The essential oil showed a predominance of monoterpene compounds, being the terpinolene, p-cymene-8-ol, and p-cymene, present in the essential oil extracted in the 3 years. The essential oil showed a protection against cyclophosphamide-induced genotoxicity, and the cytotoxicity index polychromatic erythrocytes/normochromatic erythrocytes ratio in animals treated with oil at all doses (1.34 ± 0.33; 1.15 ± 0.1; 1.11 ± 0.13) did not differ from the negative control animal (1.31 ± 0.33), but from the cyclophosphamide group (0.61 ± 0.12). Cytotoxicity, at a concentration of 40.0 μg/mL, and antimicrobial activity were not observed for the essential oil (minimum inhibitory concentration ≥0.5 mg/mL). The essential oil did not change the levels of caspase-3 in the TNF-α level. Conclusion: The essential oil showed antimutagenic activity due to its chemical composition. SUMMARY Terpinolene, p-cymene-8-ol, and p-cymene are the main constituents of the essential oil of P. heptaphyllum collected within 3-yearsThe essential oil of P. heptaphyllum did not show antimicrobial activity (MIC >0.5 mg

  8. The Resin from Protium heptaphyllum Prevents High-Fat Diet-Induced Obesity in Mice: Scientific Evidence and Potential Mechanisms.

    PubMed

    Carvalho, Karine Maria Martins Bezerra; Marinho Filho, José Delano Barreto; de Melo, Tiago Sousa; Araújo, Ana Jérsia; Quetz, Josiane da Silva; da Cunha, Maria do Perpétuo Socorro Saldanha; de Melo, Karina Moura; da Silva, Armenio Andre de Carvalho Almeida; Tomé, Adriana Rocha; Havt, Alexandre; Fonseca, Said Gonçalves da Cruz; Brito, Gerly Anne de Castro; Chaves, Mariana Helena; Rao, Vietla Satyanarayana; Santos, Flávia Almeida

    2015-01-01

    Herbal compounds rich in triterpenes are well known to regulate glucose and lipid metabolism and to have beneficial effects on metabolic disorders. The present study investigated the antiobesity properties of resin from Protium heptaphyllum (RPH) and the possible mechanisms in mice fed a high-fat diet (HFD) for 15 weeks. Mice treated with RPH showed decreases in body weight, net energy intake, abdominal fat accumulation, plasma glucose, amylase, lipase, triglycerides, and total cholesterol relative to their respective controls, which were RPH unfed. Additionally, RPH treatment, while significantly elevating the plasma level of ghrelin hormone, decreased the levels of insulin, leptin, and resistin. Besides, HFD-induced increases in plasma levels of proinflammatory mediators TNF-α, IL-6, and MCP-1 were significantly lowered by RPH. Furthermore, in vitro studies revealed that RPH could significantly inhibit the lipid accumulation in 3T3-L1 adipocytes (measured by Oil-Red O staining) at concentrations up to 50 μg/mL. These findings suggest that the antiobese potential of RPH is largely due to its modulatory effects on various hormonal and enzymatic secretions related to fat and carbohydrate metabolism and to the regulation of obesity-associated inflammation. PMID:25709707

  9. The Resin from Protium heptaphyllum Prevents High-Fat Diet-Induced Obesity in Mice: Scientific Evidence and Potential Mechanisms

    PubMed Central

    Carvalho, Karine Maria Martins Bezerra; Marinho Filho, José Delano Barreto; de Melo, Tiago Sousa; Araújo, Ana Jérsia; Quetz, Josiane da Silva; da Cunha, Maria do Perpétuo Socorro Saldanha; de Melo, Karina Moura; da Silva, Armenio Andre de Carvalho Almeida; Tomé, Adriana Rocha; Havt, Alexandre; Fonseca, Said Gonçalves da Cruz; Brito, Gerly Anne de Castro; Chaves, Mariana Helena; Rao, Vietla Satyanarayana; Santos, Flávia Almeida

    2015-01-01

    Herbal compounds rich in triterpenes are well known to regulate glucose and lipid metabolism and to have beneficial effects on metabolic disorders. The present study investigated the antiobesity properties of resin from Protium heptaphyllum (RPH) and the possible mechanisms in mice fed a high-fat diet (HFD) for 15 weeks. Mice treated with RPH showed decreases in body weight, net energy intake, abdominal fat accumulation, plasma glucose, amylase, lipase, triglycerides, and total cholesterol relative to their respective controls, which were RPH unfed. Additionally, RPH treatment, while significantly elevating the plasma level of ghrelin hormone, decreased the levels of insulin, leptin, and resistin. Besides, HFD-induced increases in plasma levels of proinflammatory mediators TNF-α, IL-6, and MCP-1 were significantly lowered by RPH. Furthermore, in vitro studies revealed that RPH could significantly inhibit the lipid accumulation in 3T3-L1 adipocytes (measured by Oil-Red O staining) at concentrations up to 50 μg/mL. These findings suggest that the antiobese potential of RPH is largely due to its modulatory effects on various hormonal and enzymatic secretions related to fat and carbohydrate metabolism and to the regulation of obesity-associated inflammation. PMID:25709707

  10. Evidence for ecological divergence across a mosaic of soil types in an Amazonian tropical tree: Protium subserratum (Burseraceae).

    PubMed

    Misiewicz, Tracy M; Fine, Paul V A

    2014-05-01

    Soil heterogeneity is an important driver of divergent natural selection in plants. Neotropical forests have the highest tree diversity on earth, and frequently, soil specialist congeners are distributed parapatrically. While the role of edaphic heterogeneity in the origin and maintenance of tropical tree diversity is unknown, it has been posited that natural selection across the patchwork of soils in the Amazon rainforest is important in driving and maintaining tree diversity. We examined genetic and morphological differentiation among populations of the tropical tree Protium subserratum growing parapatrically on the mosaic of white-sand, brown-sand and clay soils found throughout western Amazonia. Nuclear microsatellites and leaf morphology were used to (i) quantify the extent of phenotypic and genetic divergence across habitat types, (ii) assess the importance of natural selection vs. drift in population divergence, (iii) determine the extent of hybridization and introgression across habitat types, (iv) estimate migration rates among populations. We found significant morphological variation correlated with soil type. Higher levels of genetic differentiation and lower migration rates were observed between adjacent populations found on different soil types than between geographically distant populations on the same soil type. PST -FST comparisons indicate a role for natural selection in population divergence among soil types. A small number of hybrids were detected suggesting that gene flow among soil specialist populations may occur at low frequencies. Our results suggest that edaphic specialization has occurred multiple times in P. subserratum and that divergent natural selection across edaphic boundaries may be a general mechanism promoting and maintaining Amazonian tree diversity. PMID:24703227

  11. Spatial distribution and fruiting phenology of Protium heptaphyllum (Burseraceae) determine the design of the underground foraging system of Atta sexdens L. (Hymenoptera: Formicidae).

    PubMed

    da Silva, P S D; Leal, I R; Wirth, R; Tabarelli, M

    2012-08-01

    Leaf-cutting ants have long been recognized to forage via complex trail systems but the nature and the ecological drivers of the different foraging strategies adopted remain a key topic. Here, we described the spatiotemporal use of belowground foraging galleries by Atta sexdens L. in the Brazilian Atlantic forest, and examined the adaptive advantages of this foraging strategy. Protium heptaphyllum adult trees (DBH > 10 cm), seed/seedling clumps and ant gallery entrances were mapped across two 1-ha plots during two consecutive fruiting seasons (2002 and 2004). We recorded 75 ca. 40 cm deep gallery entrances beneath 26 P. heptaphyllum trees at nest distances ranging from 14 to 57 m. Furthermore, gallery abundance and galleries associated with seed/seedling clumps correlated positively with P. heptaphyllum density. Our results indicate that A. sexdens was able to set a permanent system of underground galleries targeting P. heptaphyllum trees and their seeds on the ground. Such network of galleries was spatially arranged according to both the spatial distribution and abundance of P. heptaphyllum trees in a way that most gallery entrances were disposed beneath or in close periphery of P. heptaphyllum crowns. Our findings suggest that underground trail systems shaped by fruit resources represent a foraging strategy clearly more common than existing literature on the subject would suggest. In addition, it reinforces the notion that the spatiotemporal availability of resources combined with predation risk largely influence trail configurations as well as overall foraging strategies adopted by leaf-cutting ants. PMID:23950059

  12. Habitat-specific divergence of phenolic defenses in Protium subserratum (Burseraceae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The procyanidin (PC) content of leaves from several populations of clay, brown-sand and white-sand ecotypes of P. subserratum at several sites across more than 100 km of Amazonian Peru was examined. Leaves from P. subserratum trees growing in brown-sand (BS), clay soil (CS) and white-sand (WS) habit...

  13. Structural stability of 1100{degree}C heated Pd/k during absorption cycling in protium

    SciTech Connect

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110{degree}C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100{degree}C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100{degree}C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100{degree}C.

  14. Structural stability of 1100[degree]C heated Pd/k during absorption cycling in protium. [Palladium supported on kieselguhr

    SciTech Connect

    Fisher, I.A.

    1993-03-12

    Pd/k is a hydride forming packing material which is used in the Thermal Cycling Absorption Process (TCAP). Palladium is supported on kieselguhr to create a packing material which will provide adequate void space to prevent excessive pressure drops and flow restrictions. The use of unsupported palladium would result in blockage of columns and clogging of filters due to the small particle size of unsupported palladium hydride powder. During pilot scale demonstrations, it was noted that the Pd/k packing material had degraded causing severe flow restrictions within the TCAP column. A solution to the problem involved the heating of Pd/k at 1,110[degree]C to strengthen the packing material, and render it more resistant to breakdown. The 1, 100[degree]C heated Pd/k has been shown to be more resistant to mechanical breakdown than the Pd/k prior to heat treatment. Two primary modes of Pd/k particle degradation have been identified: mechanical breakdown caused by particle fluidization and degradation caused by absorption/desorption cycling. Absorption/desorption cycling causes the palladium particles within the packing to expanded and contract upon formation and decomposition of the hydride, respectively. This expansion and contraction causes large localized stresses within the packing material, which if these stresses can not be accommodated within the packing will cause the material to crack and degrade. The purpose of this report is to document the results of the absorption/desorption cycling of 1,100[degree]C heated Pd/k and compare these results to the results obtained from the absorption/desorption cycling of Pd/k which had not been heated at 1, 100[degree]C.

  15. Effectiveness of passivation techniques on hydrogen desorption in a tritium environment

    NASA Astrophysics Data System (ADS)

    Woodall, Steven Michael

    2009-11-01

    Tritium is a radioactive isotope of hydrogen. It is used as a fuel in fusion reactors, a booster material in nuclear weapons and as a light source in commercial applications. When tritium is used in fusion reactors, and especially when used in the manufacture of nuclear weapons, purity is critical. For U.S. Department of Energy use, tritium is recycled by Savannah River Site in South Carolina and is processed to a minimum purity of 99.5%. For use elsewhere in the country, it must be shipped and stored, while maintaining the highest purity possible. As an isotope of hydrogen it exchanges easily with the most common isotope of hydrogen, protium. Stainless steel bottles are used to transport and store tritium. Protium, present in air, becomes associated in and on the surface of stainless steel during and after the manufacture of the steel. When filled, the tritium within the bottle exchanges with the protium in and on the surface of the stainless steel, slowly contaminating the pure tritium with protium. The stainless steel is therefore passivated to minimize the protium outgrowth of the bottles into the pure tritium. This research is to determine how effective different passivation techniques are in minimizing the contamination of tritium with protium. Additionally, this research will attempt to determine a relationship between surface chemistry of passivated steels and protium contamination of tritium. The conclusions of this research found that passivated bottles by two companies which routinely provide passivated materials to the US Department of Energy provide low levels of protium outgrowth into pure tritium. A bottle passivated with a material to prevent excessive corrosion in a highly corrosive environment, and a clean and polished bottle provided outgrowth rates roughly twice those of the passivated bottles above. Beyond generally high levels of chromium, oxygen, iron and nickel in the passivated bottles, there did not appear to be a strong correlation

  16. Hydrogen isotope transfer in austenitic steels and high-nickel alloy during in-core irradiation

    SciTech Connect

    Polosukhin, B.G.; Sulimov, E.M.; Zyrianov, A.P.; Kalinin, G.M.

    1995-10-01

    The transfer of protium and deuterium in austenitic chromium-nickel steels and in a high-nickel alloy was studied in a specially designed facility. The transfer parameters of protium and deuterium were found to change greatly during in-core irradiation, and the effects of irradiation increased as the temperature decreased. Thus, at temperature T<673K, the relative increase in the permeability of hydrogen isotopes under irradiation can be orders of magnitude higher in these steels. Other radiation effects were also observed, in addition to the changes from the initial values in the effects of protium and deuterium isotopic transfer. 4 refs., 3 figs., 2 tabs.

  17. Tritium transport vessel using depleted uranium

    SciTech Connect

    Heung, L.K.

    1995-01-01

    A tritium transport vessel using depleted uranium was tested in the laboratory using deuterium and protium. The vessel contains 0.5 kg of depleted uranium and can hold up to 18 grams of tritium. The conditions for activation, tritium loading and tritium unloading were defined. The safety aspects that included air-ingress, tritium diffusion, temperature and pressure potentials were evaluated.

  18. Issues Arising from Plasma-Wall Interactions in Inner-Class Tokamaks

    SciTech Connect

    Wampler, William R.

    1999-06-23

    This section reviews physical processes involved in the implantation of energetic hydrogen into plasma facing materials and its subsequent diffusion, release, or immobilization by trapping or precipitation within the material. These topics have also been discussed in previous reviews. The term hydrogen or H is used here generically to refer to protium, deuterium or tritium.

  19. Polyimide and polyamide-imide in a tritium atmosphere

    SciTech Connect

    Wylie, K.F.; Hockett, J.E.; Buxton, T.L.

    1981-01-01

    Five different commercial polyamide-imide and polyimide specimens were kept in a tritium atmosphere (96.9 mol %, 101 kPa, initial fill conditions) for three months. Selected physical and mechanical properties of the five plastics were examined. Mass spectrometric data showed the growth of protium and HT impurity in the tritium gas.

  20. Effects of tritium on material properties

    SciTech Connect

    Caskey, G.R. Jr.

    1985-01-01

    The effecs of tritium on deformation and fracture of metals are reviewed with emphasis on similarities and differences between tritium and the other hydrogen isotopes. Helium generated by radioactive decay of tritium introduces time dependent property changes not observed with protium or deuterium. On-going studies and topics for further investigations are identified. 17 refs., 6 figs., 9 tabs.

  1. DEMONSTRATION OF THE NEXT-GENERATION TCAP HYDROGEN ISOTOPE SEPARATION PROCESS

    SciTech Connect

    Heung, L; Henry Sessions, H; Steve Xiao, S; Heather Mentzer, H

    2009-01-09

    The first generation of TCAP hydrogen isotope separation process has been in service for tritium separation at the Savannah River Site since 1994. To prepare for replacement, a next-generation TCAP process has been developed. This new process simplifies the column design and reduces the equipment requirements of the thermal cycling system. An experimental twelve-meter column was fabricated and installed in the laboratory to demonstrate its performance. This new design and its initial test results were presented at the 8th International Conference on Tritium Science and Technology and published in the proceedings. We have since completed the startup and demonstration the separation of protium and deuterium in the experimental unit. The unit has been operated for more than 200 cycles. A feed of 25% deuterium in protium was separated into two streams each better than 99.7% purity.

  2. Investigation of hydrogen isotope exchange reaction rate in mixed gas (H{sub 2} and D{sub 2}) at pressure up to 200 MPa using Raman spectroscopy

    SciTech Connect

    Tikhonov, V.V.; Yukhimchuk, A.A.; Musyayev, R.K.; Gurkin, A.I.

    2015-03-15

    Raman spectroscopy is a relevant method for obtaining objective data on isotopic exchange rate in a gaseous mix of hydrogen isotopes, since it allows one to determine a gaseous mix composition in real time without sampling. We have developed a high-pressure fiber-optic probe to be used for obtaining protium Raman spectra under pressures up to 400 MPa and we have recorded spectral line broadening induced by molecule collisions starting from ∼ 40 MPa. Using this fiber-optic probe we have performed experiments to study isotopic exchange kinetics in a gaseous mix of hydrogen isotopes (protium-deuterium) at pressures up to 200 MPa. Preliminary results show that the dependence of the average isotopic exchange rate related to pressure take unexpected values at the very beginning of the time evolution. More work is required to understand this inconsistency.

  3. Muon transfer from hydrogen and deuterium atoms to neon

    SciTech Connect

    Jacot-Guillarmod, R. )

    1995-03-01

    The muon exchange reactions from the ground state of muonic protium and deuterium atoms to neon are studied. Measurements have been performed in binary gas mixtures at room temperature. The transfer rate from thermalized muonic deuterium is found to exceed by about an order of magnitude the one from muonic protium. On the other hand, an energy dependence of the rate from [mu][ital d] is revealed, while none is observed from [mu][ital p]. The intensity patterns of the muonic Lyman series of neon resulting from the muon exchange differ from one hydrogen isotope to the other, the most obvious discrepancy being the presence of the muonic Ne(7-1) line after transfer from [mu][ital d], whereas this line is absent by transfer from [mu][ital p]. This indicates that the muon is transferred to the level [ital n][sub [ital p

  4. Hydrogen transport in iron and steel

    NASA Technical Reports Server (NTRS)

    Louthan, M. R., Jr.; Derrick, R. G.; Donovan, J. A.; Caskey, G. R., Jr.

    1976-01-01

    The permeabilities of protium, deuterium, and tritium in foil specimens of Marz grade iron, 4130 steel, Armco iron, HP-9-4-20, and T-1 steels were studied at hydrogen pressures between 0.02 and 0.5 MPa over the temperature range 260-700 K. The permeability was measured by a pressure-rise method, deuterium counting with a detector, and radioactivity counting. Good agreement is found between the measurement techniques used. It is shown that the permeabilities of protium, deuterium, and tritium in iron and T-1 steel at temperatures as low as 260 K are in good agreement with the equation proposed by Gonzalez (1967). However, the permeabilities of HP-9-4-20 and 4130 steel to hydrogen are typically lower than predicted. The isotope effect on hydrogen permeability of HP-9-4-20, 4130 and T-1 steels, and high-purity iron can be estimated by an inverse square root of mass correction.

  5. Permeability of Molecular Hydrogen and Water Vapor Through Butyl Rubber at Ambient Temperature

    SciTech Connect

    Zeigler, K.

    1992-04-09

    The preparation of the Safety Analysis Report for the 233-H Replacement Tritium Facility (RTF) requires permeation constants of hydrogen isotopes through butyl rubber, to estimate possible worker exposure given a certain level of tritium in the confinement gloveboxes. Literature values of the permeability constants for hydrogen isotopes and water vapor through butyl rubber at ambient temperature (22-25 C) have been converted to common units and are tabulated (Tables I and II). Permeation rates of tritiated species are the same as that of protium species, within experimental error. Thus, molecular protium and normal water vapor data serve to estimate tritium permeation rates. Because of vendor to vendor variability of permeability, especially of water vapor, vendor measurements of water vapor permeability should continue to be used to estimate permeation in SRS processes.

  6. Permeability of Molecular Hydrogen and Water Vapor Through Butyl Rubber at Ambient Temperature

    SciTech Connect

    Clark, Elliot A.

    1992-04-09

    The preparation of the Safety Analysis Report for the 233-H Replacement Tritium Facility (RTF) requires permeation constants of hydrogen isotopes through butyl rubber, to estimate possible worker exposure given a certain level of tritium in the confinement gloveboxes. Literature values of the permeability constants for hydrogen isotopes and water vapor through butyl rubber at ambient temperature (22-25 C) have been converted to common units and are tabulated (Tables I and II). Permeation rates of tritiated species are the same as that of protium species, within experimental error. Thus, molecular protium and normal water vapor data serve to estimate tritium permeation rates. Because of vendor-to-vendor variability of permeability, especially of water vapor, vendor measurements of water vapor permeability should continue to be used to estimate permeation in SRS processes.

  7. Chemical Composition and Biological Activities of Fragrant Mexican Copal (Bursera spp.).

    PubMed

    Gigliarelli, Giulia; Becerra, Judith X; Curini, Massimo; Marcotullio, Maria Carla

    2015-01-01

    Copal is the Spanish word used to describe aromatic resins from several genera of plants. Mexican copal derives from several Bursera spp., Protium copal, some Pinus spp. (e.g., P. pseudostrobus) and a few Fabaceae spp. It has been used for centuries as incense for religious ceremonies, as a food preservative, and as a treatment for several illnesses. The aim of this review is to analyze the chemical composition and biological activity of commercial Mexican Bursera copal. PMID:26703535

  8. Isotopic Separation Analysis of Infinitesimal Concentrations of Hydrogen Using Trace Reduction Detector

    SciTech Connect

    Kawano, Takao; Tsuboi, Naohiro; Tsujii, Hirotsugu; Asakura, Yamato; Uda, Tatsuhiko

    2005-07-15

    A previously developed analyzer for detecting extremely small concentrations of hydrogen in air was evaluated by using it to distinguish hydrogen isotopes. The analyzer utilizes the functions of a gas chromatograph and an atomic absorption spectrophotometer and is based on the reduction reaction of mercuric oxide with hydrogen. Three test samples were used: gas mixtures containing both protium and deuterium with almost equal concentrations of about 5, 20, or 50 cm{sup 3}/1000 m{sup 3} diluted in nitrogen. Each measurement was repeated more than 30 times, and chromatograms were obtained for each test sample. Examination of the chromatograms showed that the retention times for the protium and deuterium could be clearly distinguished. The retention times were virtually constant and indistinguishable, independent of the concentration and repetition time. The peak areas for the protium and deuterium were also stable, independent of the repetition time. Moreover, there was a clear linear relationship between the peak areas and concentrations for both elements. These results show that the analyzer can distinguish the two hydrogen isotopes and estimate concentrations of each as small as about 5 cm{sup 3}/1000 m{sup 3}. They also show that it may be possible to use the analyzer to monitor tritium concentrations.

  9. Multiple isotope effects with alternative dinucleotide substrates as a probe of the malic enzyme reaction

    SciTech Connect

    Weiss, P.M.; Urbauer, J.L.; Cleland, W.W. ); Gavva, S.R.; Harris, B.G.; Cook, P.F. )

    1991-06-11

    Deuterium isotope effects and {sup 13}C isotope effects with deuterium- and protium-labeled malate have been obtained for both NAD- and NADP-malic enzymes by using a variety of alternative dinucleotide substrates. With nicotinamide-containing dinucleotides as the oxidizing substrate, the {sup 13}C effect decreases when deuterated malate is the substrate compared to the value obtained with protium-labeled malate. These data are consistent with a stepwise chemical mechanism in which hydride transfer precedes decarboxylation of the oxalacetate intermediate as previously proposed. When dinucleotide substrates such as thio-NAD, 3-nicotinamide rings are used, the {sup 13}C effect increases when deuterated malate is the substrate compared to the value obtained with protium-labeled malate. These data, at face value, are consistent with a change in mechanism from stepwise to concerted for the oxidative decarboxylation portion of the mechanism. However, the increase in the deuterium isotope effect from 1.5 to 3 with a concomitant decrease in the {sup 13}C isotope effect from 1.034 to 1.003 as the dinucleotide substrate is changed suggests that the reaction may still be stepwise with the non-nicotinamide dinucleotides. A more likely explanation is that a {beta}-secondary {sup 13}C isotope effect accompanies hydride transfer as a result of hyperconjugation of the {beta}-carboxyl of malate as the transition state for the hydride transfer step is approached.

  10. Coal structure and behavior: Interfacial chemistry in coal

    SciTech Connect

    Ross, D.S.; Hirschon, A.S.; Green, T.K.

    1988-01-01

    In an attempt to evaluate the importance of interfacial chemistry to coal behavior, we have conducted studies at 400[degrees]C with both H[sub 2]O and D[sub 2]O, using both Illinois No. 6 coal (PSOC 1098) and pure organic compounds. Figure 3 summarizes our effort, and virtually none of the material presented here is consistent with the organic structures depicted in Figure 1. We found that while coal recovered from simple hydrothermal treatment in D[sub 2]O/N[sub 2] for 20 minutes under nitrogen contained more than 90% of the starting carbon, 36% of the starting hydrogen and about half the starting oxygen were lost. Our account of the anomalous O-loss has recently appeared (2). These loses could not be accounted for by CO[sub x] and light hydrocarbon evolution. Of the remaining protium in the product, 53% had been exchanged for deuterium. The product had been subjected to back-exchange in H[sub 2]O at mild conditions to convert the phenolic hydrogen to protium, so the large levels of exchange were strictly for hydrogen bonded to carbon. These findings can be compared with those from work with work under the same conditions with pure organic materials. At 20 minutes in D[sub 2]O we found no trace of exchange for benzene, toluene, or bibenzyl. Thus, the benzyl-protium exchange rate in coal is roughly 100 times faster than that for bibenzyl and considerably faster than that for toluene. This result can be translated to suggest that the thermal generation of free radical sites in the coal operates at a rate two to three orders of magnitude greater than that for bibenzyl. However no feature in the organic structures proposed for coal can generate such a flux of reactive free radicals by a wide margin.

  11. Coal structure and behavior: Interfacial chemistry in coal

    SciTech Connect

    Ross, D.S.; Hirschon, A.S.; Green, T.K.

    1988-12-31

    In an attempt to evaluate the importance of interfacial chemistry to coal behavior, we have conducted studies at 400{degrees}C with both H{sub 2}O and D{sub 2}O, using both Illinois No. 6 coal (PSOC 1098) and pure organic compounds. Figure 3 summarizes our effort, and virtually none of the material presented here is consistent with the organic structures depicted in Figure 1. We found that while coal recovered from simple hydrothermal treatment in D{sub 2}O/N{sub 2} for 20 minutes under nitrogen contained more than 90% of the starting carbon, 36% of the starting hydrogen and about half the starting oxygen were lost. Our account of the anomalous O-loss has recently appeared (2). These loses could not be accounted for by CO{sub x} and light hydrocarbon evolution. Of the remaining protium in the product, 53% had been exchanged for deuterium. The product had been subjected to back-exchange in H{sub 2}O at mild conditions to convert the phenolic hydrogen to protium, so the large levels of exchange were strictly for hydrogen bonded to carbon. These findings can be compared with those from work with work under the same conditions with pure organic materials. At 20 minutes in D{sub 2}O we found no trace of exchange for benzene, toluene, or bibenzyl. Thus, the benzyl-protium exchange rate in coal is roughly 100 times faster than that for bibenzyl and considerably faster than that for toluene. This result can be translated to suggest that the thermal generation of free radical sites in the coal operates at a rate two to three orders of magnitude greater than that for bibenzyl. However no feature in the organic structures proposed for coal can generate such a flux of reactive free radicals by a wide margin.

  12. Equations of state and phase diagrams of hydrogen isotopes

    SciTech Connect

    Urlin, V. D.

    2013-11-15

    A new form of the semiempirical equation of state proposed for the liquid phase of hydrogen isotopes is based on the assumption that its structure is formed by cells some of which contain hydrogen molecules and others contain hydrogen atoms. The values of parameters in the equations of state of the solid (molecular and atomic) phases as well as of the liquid phase of hydrogen isotopes (protium and deuterium) are determined. Phase diagrams, shock adiabats, isentropes, isotherms, and the electrical conductivity of compressed hydrogen are calculated. Comparison of the results of calculations with available experimental data in a wide pressure range demonstrates satisfactory coincidence.

  13. Exotic atoms. Technical progress report, February 1, 1992--January 31, 1993

    SciTech Connect

    Kunselman, R.

    1993-03-01

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation.

  14. Exotic atoms. [Univ. of Wyoming, Laramie, Wyoming

    SciTech Connect

    Kunselman, R.

    1993-01-01

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation.

  15. Exotic atoms: Muonic atoms into vacuum from solid hydrogen. Technical progress report, February 1, 1994--January 31, 1995

    SciTech Connect

    Kunselman, R.

    1993-12-31

    The experiments use various solid hydrogen layers to form various muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation.

  16. Development of nuclear micro-battery with solid tritium source.

    PubMed

    Lee, Sook-Kyung; Son, Soon-Hwan; Kim, KwangSin; Park, Jong-Wan; Lim, Hun; Lee, Jae-Min; Chung, Eun-Su

    2009-01-01

    A micro-battery powered by tritium is being developed to utilize tritium produced from the Wolsong Tritium Removal Facility. The 3D p-n junction device has been designed and fabricated for energy conversion. Titanium tritide is adopted to increase tritium density and safety. Sub micron films or nano-powders of titanium tritide is applied on silicon semiconductor device to reduce the self absorption of beta rays. Until now protium has been used instead of tritium for safety. Hydrogen was absorbed up to atomic ratio of approximately 1.3 and approximately 1.7 in titanium powders and films, respectively. PMID:19328704

  17. Gas handling systems using titanium-sponge and uranium bulk getters

    SciTech Connect

    Kherani, N.P.; Shmayda, W.T.

    1985-09-01

    A protium gas handling system using titanium and uranium bulk getters was designed, constructed and tested. Numerous process operations were carried out on this system to aid in the design of a tritium gas handling system four times the experimental scale. Experimental results have shown that high percentages of tritium on long-term titanium storage beds can be recovered in a relatively short period of time and be transferred to uranium bed(s) in direct (pump-less) and pump-aided transfers. An optimum storage time after which the rate of interstitial /sup 3/He evolution would be prohibitive to conduct direct tritium transfers is estimated.

  18. New Systems for Waste Processing of Tritium-Containing Gases at the Savannah River Site

    SciTech Connect

    Poore, A.S.; Jacobs, W.D.

    2005-07-15

    A project to relocate and consolidate tritium processing activities from old, second generation buildings to newer buildings was initiated in the late 1990's at the Savannah River Site. The new waste gas processing systems located in the newer facility utilize recent technology, including metal getters, an innovative permeator design, and TCAP (Thermal Cycling Absorption Process) technology for removal of residual tritium prior to releasing the effluent to the environment. Startup testing results (using protium and deuterium) and corresponding lessons learned for these systems are presented. These systems have since successfully completed tritium startup testing and are operational.

  19. Reaction Rates for the Formation of Deuterium Tritide from Deuterium and Tritium

    SciTech Connect

    McConville, G. T.; Menke, D. A.; Ellefson, R. E.

    1985-04-01

    The rates of formation of DT in a mixture of D2 and T2 have been measured as a function of initial T2 concentration, pressure, temperature,and methane concentration in a stainless steel reaction container which had been treated to inhibit protium ingrowth. An attempt has been made to explain the experimental resuts on the basis of ion-molecule chain reactions. Some of the observations are consistent with a gas-phase ion, ground-state molecule reaction, but some of the more interesting observations require more complicated models. The addition of excited state molecules or heterogeneous catalytic effects are possibilities that will need further experiments for confirmation.

  20. TMED-4 INTERIM REPORT PURE ZR EQUILIBRIUM TEST RESULTS

    SciTech Connect

    Korinko, P.; Morgan, G.

    2010-12-17

    Due to higher than expected permeation rates in the production of tritium in the TVA, a development and testing program was implemented to develop the understanding of why the higher rates were occurring. In addition, improved data are needed for both the design as well as the predictive models. One part of the program was to determine the equilibrium pressure of hydrogen and tritium over NPZ (1). During the course of this testing, some curious results were discovered (2) compared to the published literature data (3). Due to these apparently results, a follow-on task was undertaken to determine the equilibrium pressure of protium and deuterium over pure zirconium. A series of experiments were conducted to determine equilibrium pressures and isotherm data for the zirconium - protium and zirconium - deuterium systems. The data match the published literature data reasonably well with the plateau extending to loadings of about 1.4. There is a significant pressure rise for loadings greater than 1.7.

  1. Experiments on water detritiation and cryogenic distillation at TLK; Impact on ITER fuel cycle subsystems interfaces

    SciTech Connect

    Cristescu, I.; Cristescu, I. R.; Doerr, L.; Hellriegel, G.; Michling, R.; Murdoch, D.; Schaefer, P.; Welte, S.; Wurster, W.

    2008-07-15

    The ITER Isotope Separation System (ISS) and Water Detritiation System (WDS) should be integrated in order to reduce potential chronic tritium emissions from the ISS. This is achieved by routing the top (protium) product from the ISS to a feed point near the bottom end of the WDS Liquid Phase Catalytic Exchange (LPCE) column. This provides an additional barrier against ISS emissions and should mitigate the memory effects due to process parameter fluctuations in the ISS. To support the research activities needed to characterize the performances of various components for WDS and ISS processes under various working conditions and configurations as needed for ITER design, an experimental facility called TRENTA representative of the ITER WDS and ISS protium separation column, has been commissioned and is in operation at TLK The experimental program on TRENTA facility is conducted to provide the necessary design data related to the relevant ITER operating modes. The operation availability and performances of ISS-WDS have impact on ITER fuel cycle subsystems with consequences on the design integration. The preliminary experimental data on TRENTA facility are presented. (authors)

  2. Characterization of titanium films in the Tandem Mirror Experiment Upgrade (TMX-U)

    SciTech Connect

    Hsu, W.L.; Bastasz, R.; Bauer, W.; Malinowski, M.E.; Mills, B.E.; Allen, S.L.; Clower, C.A.

    1984-04-01

    Titanium gettering is used extensively in the Tandem Mirror Experiment Upgrade (TMX-U) to achieve good vacuum conditions for the production of a sustained energetic plasma. The gettering films under different operating conditions were analyzed by thermal desorption spectroscopy and Auger electron spectroscopy. A sputter profile of the films showed a Ti deposition rate of approx. =1 nm per evaporation sequence. Large quantities of protium (H/Tiroughly-equal0.2), oxygen (O/Tiroughly-equal0.3), and carbon (C/Tiroughly-equal0.1) were detected in the films regardless of their location and the plasma isotope to which they were exposed. While the Ti films that were exposed to deuterium plasmas showed a substantial increase in deuterium content, deuterium still remained a small fraction of the overall hydrogen concentration (D/Hroughly-equal0.1). Analyses of the results suggest that getter pumping of H/sub 2/O from the background gas in the (TMX-U) vacuum system is the primary source for protium and oxygen measured in the films.

  3. Choice of a process design for simultaneous detritiation and upgrading of heavy water for the Advanced Neutron Source

    SciTech Connect

    Miller, A.I.; Spagnolo, D.A.; DeVore, J.R.

    1995-11-01

    Tritium removal and heavy water upgrading are essential components of the heavy water-moderated reactor that is the heart of the Advanced Neutron Source (ANS) to be built at Oak Ridge National Laboratory. The technologies for these two processes, which are closely related, are reviewed in the context of the ANS requirements. The evolution of the design of the Heavy Water Upgrading and Detritiation Facility (HWUDF) for ANS is outlined, and the final conceptual design is presented. The conceptual design of HWUDF has two main component systems: (a) a front-end combined electrolysis and catalytic exchange (CECE) system and (b) a back-end cryogenic distillation (CD) system. The CECE process consists of a countercurrent exchange column for hydrogen-water exchange over a wetproofed catalyst and electrolysis to convert water into hydrogen. It accepts all the tritiated heavy water streams of the reactor and performs an almost total separation into a protium (light hydrogen) stream containing tritium and deuterium at only natural abundance and a deuterium stream containing all the tritium and almost no protium. The tritium-containing deuterium stream is then processed by a CD unit, which removes over 90% of the tritium and concentrates it to >99% tritium for indefinite storage as a metal tritide. Deuterium gas with a small residue of tritium is recombined with oxygen from the electrolytic cells and returned as heavy water to the reactor.

  4. Pf/Zeolite Catalyst for Tritium Stripping

    SciTech Connect

    Hsu, R.H.

    2001-03-26

    This report described promising hydrogen (protium and tritium) stripping results obtained with a Pd/zeolite catalyst at ambient temperature. Preliminary results show 90-99+ percent tritium stripping efficiency may be obtained, with even better performance expected as bed configuration and operating conditions are optimized. These results suggest that portable units with single beds of the Pd/zeolite catalyst may be utilized as ''catalytic absorbers'' to clean up both tritium gas and tritiated water. A cart-mounted prototype stripper utilizing this catalyst has been constructed for testing. This portable stripper has potential applications in maintenance-type jobs such as tritium line breaks. This catalyst can also potentially be utilized in an emergency stripper for the Replacement Tritium Facility.

  5. Apparatus for separating and recovering hydrogen isotopes

    DOEpatents

    Heung, Leung K.

    1994-01-01

    An apparatus for recovering hydrogen and separating its isotopes. The apparatus includes a housing bearing at least a fluid inlet and a fluid outlet. A baffle is disposed within the housing, attached thereto by a bracket. A hollow conduit is coiled about the baffle, in spaced relation to the baffle and the housing. The coiled conduit is at least partially filled with a hydride. The hydride can be heated to a high temperature and cooled to a low temperature quickly by circulating a heat transfer fluid in the housing. The spacing between the baffle and the housing maximizes the heat exchange rate between the fluid in the housing and the hydride in the conduit. The apparatus can be used to recover hydrogen isotopes (protium, deuterium and tritium) from gaseous mixtures, or to separate hydrogen isotopes from each other.

  6. Performance of a metal hydride store on the "Ross Barlow" hydrogen powered canal boat.

    PubMed

    Bevan, A I; Züttel, A; Book, D; Harris, I R

    2011-01-01

    This project involved the conversion of a British Waterways maintenance craft to a canal boat, powered by a combination of a solid-state hydrogen store, Proton Exchange Membrane (PEM) fuel cell, lead-acid battery pack and a high-efficiency, permanent magnet (NdFeB) electric motor. These replaced the conventional diesel engine thus eliminating water, noise, local and general atmospheric pollution. The "Protium" project applies modern technologies to a traditional mode of transportation. The TiMn2-based metal hydride store exhibited excellent performance as an effective means of storing 4 kg of hydrogen with a suitable desorption flow rate and temperature adequate for the operation of a 1 kW PEM fuel cell in a water-based environment. PMID:22455080

  7. INSTRUMENTS AND METHODS OF INVESTIGATION: Dynamic compression of hydrogen isotopes at megabar pressures

    NASA Astrophysics Data System (ADS)

    Trunin, Ryurik F.; Urlin, Vitalii D.; Medvedev, Aleksandr B.

    2010-09-01

    We review the results of shock compression of solid protium to the pressure 66 GPa, of liquid deuterium to 110 GPa, and of solid deuterium to 123 GPa in explosive devices of spherical geometry. The results are compared with data obtained by US scientists using traditional energy sources (explosives and light-gas guns), striker acceleration in a strong magnetic field (Z facility at Sandia), and powerful lasers (Nova at Lawrence Livermore National Laboratory (LLNL) and Omega at the Laboratory for Laser Energetics, University of Rochester). Results of density measurements of hydrogen isotopes under quasi-isentropic compression are analyzed. The absence of an anomalous increase in density under shock and quasi-isentropic compression of hydrogen isotopes is demonstrated. On the other hand, both processes exhibit a sharp change in the compression curve slopes, at the respective pressures 45 and 300 GPa.

  8. Reaction rates and kinetic isotope effects of H2 + OH → H2O + H.

    PubMed

    Meisner, Jan; Kästner, Johannes

    2016-05-01

    We calculated reaction rate constants including atom tunneling of the reaction of dihydrogen with the hydroxy radical down to a temperature of 50 K. Instanton theory and canonical variational theory with microcanonical optimized multidimensional tunneling were applied using a fitted potential energy surface [J. Chen et al., J. Chem. Phys. 138, 154301 (2013)]. All possible protium/deuterium isotopologues were considered. Atom tunneling increases at about 250 K (200 K for deuterium transfer). Even at 50 K the rate constants of all isotopologues remain in the interval 4 ⋅ 10(-20) to 4 ⋅ 10(-17) cm(3) s(-1), demonstrating that even deuterated versions of the title reaction are possibly relevant to astrochemical processes in molecular clouds. The transferred hydrogen atom dominates the kinetic isotope effect at all temperatures. PMID:27155636

  9. Reaction rates and kinetic isotope effects of H2 + OH → H2O + H

    NASA Astrophysics Data System (ADS)

    Meisner, Jan; Kästner, Johannes

    2016-05-01

    We calculated reaction rate constants including atom tunneling of the reaction of dihydrogen with the hydroxy radical down to a temperature of 50 K. Instanton theory and canonical variational theory with microcanonical optimized multidimensional tunneling were applied using a fitted potential energy surface [J. Chen et al., J. Chem. Phys. 138, 154301 (2013)]. All possible protium/deuterium isotopologues were considered. Atom tunneling increases at about 250 K (200 K for deuterium transfer). Even at 50 K the rate constants of all isotopologues remain in the interval 4 ṡ 10-20 to 4 ṡ 10-17 cm3 s-1, demonstrating that even deuterated versions of the title reaction are possibly relevant to astrochemical processes in molecular clouds. The transferred hydrogen atom dominates the kinetic isotope effect at all temperatures.

  10. Evaluation of Hydrogen Isotope Exchange Methodology on Adsorbents for Tritium Removal

    SciTech Connect

    Morgan, Gregg A.; Xiao, S. Xin

    2015-03-06

    The Savannah River National Laboratory has demonstrated a potential process that can be used to remove tritium from tritiated water using Pt-catalyzed molecular sieves. The process is an elemental isotope exchange process in which H2 (when flowed through the molecular sieves) will exchange with the adsorbed water, D2O, leaving H2O adsorbed on the molecular sieves. Various formulations of catalyzed molecular sieve material were prepared using two different techniques, Pt-implantation and Pt-ion exchange. This technology has been demonstrated for a protium (H) and deuterium (D) system, but can also be used for the removal of tritium from contaminated water (T2O, HTO, and DTO) using D2 (or H2)

  11. Evaluation of hydrogen isotope exchange methodology on adsorbents for tritium removal

    SciTech Connect

    Morgan, G.A.; Xin Xiao, S.

    2015-03-15

    The Savannah River National Laboratory has demonstrated a potential process that can be used to remove tritium from tritiated water using Pt-catalyzed molecular sieves. The process is an elemental isotope exchange process in which H{sub 2} (when flowed through the molecular sieves) will exchange with the adsorbed water, D{sub 2}O, leaving H{sub 2}O adsorbed on the molecular sieves. Various formulations of catalyzed molecular sieve material were prepared using two different techniques, Pt-implantation and Pt-ion exchange. This technology has been demonstrated for a protium (H) and deuterium (D) system, but can also be used for the removal of tritium from contaminated water (T{sub 2}O, HTO, and DTO) using D{sub 2} (or H{sub 2}). (authors)

  12. Tritium transport vessel using depleted uranium

    SciTech Connect

    Heung, L.K.

    1995-10-01

    A tritium transport vessel using depleted uranium was tested in the laboratory using deuterium and protium. The vessel contains 0.5 kg of depleted uranium and can hold up to 18 grams of tritium. The conditions for activation, tritium loading and tritium unloading were defined. The safety aspects that included air-ingress, tritium diffusion, temperature and pressure potentials were evaluated. Air ingress did not cause any temperature surge when the uranium was fully hydrided, but created a temperature peak of 200 {degree}C when the uranium was dehydrided. Accumulation of non-reactive gases such as argon and moisture in the air blocked further air ingress. Only a flow-through type of air ingress could damage the vessel. 6 refs., 9 figs.

  13. NNSA TRITIUM SUPPLY CHAIN

    SciTech Connect

    Wyrick, Steven; Cordaro, Joseph; Founds, Nanette; Chambellan, Curtis

    2013-08-21

    Savannah River Site plays a critical role in the Tritium Production Supply Chain for the National Nuclear Security Administration (NNSA). The entire process includes: • Production of Tritium Producing Burnable Absorber Rods (TPBARs) at the Westinghouse WesDyne Nuclear Fuels Plant in Columbia, South Carolina • Production of unobligated Low Enriched Uranium (LEU) at the United States Enrichment Corporation (USEC) in Portsmouth, Ohio • Irradiation of TPBARs with the LEU at the Tennessee Valley Authority (TVA) Watts Bar Reactor • Extraction of tritium from the irradiated TPBARs at the Tritium Extraction Facility (TEF) at Savannah River Site • Processing the tritium at the Savannah River Site, which includes removal of nonhydrogen species and separation of the hydrogen isotopes of protium, deuterium and tritium.

  14. Hydrogen compatibility handbook for stainless steels

    SciTech Connect

    Caskey, G.R. Jr.

    1983-06-01

    This handbook compiles data on the effects of hydrogen on the mechanical properties of stainless steels and discusses this data within the context of current understanding of hydrogen compatibility of metals. All of the tabulated data derives from continuing studies of hydrogen effects on materials that have been conducted at the Savannah River Laboratory over the past fifteen years. Supplementary data from other sources are included in the discussion. Austenitic, ferritic, martensitic, and precipitation hardenable stainless steels have been studied. Damage caused by helium generated from decay of tritium is a distinctive effect that occurs in addition to the hydrogen isotopes protium and deuterium. The handbook defines the scope of our current knowledge of hydrogen effects in stainless steels and serves as a guide to selection of stainless steels for service in hydrogen.

  15. Evaluation of Hydrogen Isotope Exchange Methodology on Adsorbents for Tritium Removal

    DOE PAGESBeta

    Morgan, Gregg A.; Xiao, S. Xin

    2015-03-06

    The Savannah River National Laboratory has demonstrated a potential process that can be used to remove tritium from tritiated water using Pt-catalyzed molecular sieves. The process is an elemental isotope exchange process in which H2 (when flowed through the molecular sieves) will exchange with the adsorbed water, D2O, leaving H2O adsorbed on the molecular sieves. Various formulations of catalyzed molecular sieve material were prepared using two different techniques, Pt-implantation and Pt-ion exchange. This technology has been demonstrated for a protium (H) and deuterium (D) system, but can also be used for the removal of tritium from contaminated water (T2O, HTO,more » and DTO) using D2 (or H2)« less

  16. Tritium stripping in a nitrogen glove box using palladium/zeolite and SAES St 198{trademark}

    SciTech Connect

    Klien, J.E.; Wermer, J.R.

    1995-01-01

    Glove box clean-up experiments were conducted in a nitrogen glove box using palladium deposited on zeolite (Pd/z) and a SAES St 198{trademark} getter as tritium stripping materials. Protium/deuterium samples spiked with tritium were released into a 620 liter glove box to simulate tritium releases in a 10,500 liter glove box. The Pd/z and the SAES St 198{trademark} stripper beds produced a reduction in tritium activity of approximately two to three orders of magnitude and glove box clean-up was limited by a persistent background tritium activity level. Attempts to significantly reduce the glove box activity to lower levels without purging were unsuccessful.

  17. Tritium stripping in a nitrogen glove box using palladium/zeolite and SAES St 198

    SciTech Connect

    Klein, J.E.; Wermer, J.R.

    1995-10-01

    Glove box clean-up experiments were conducted in a nitrogen glove box using palladium deposited on zeolite (Pd/z) and a SAES St 198 getter as tritium stripping materials. Protium/deuterium samples spiked with tritium were released into a 620 liter glove box to simulate tritium releases in a 10,500 liter glove box. The Pd/z and the SAES St 198 stripper beds produced a reduction in tritium activity of approximately two to three orders of magnitude and glove box clean-up was limited by a persistent background tritium activity level. Attempts to significantly reduce the glove box activity to lower levels without purging were unsuccessful. 3 refs., 6 figs., 1 tab.

  18. Comments on the stability of charge states and locations for hydrogen and muonium in semiconductors

    NASA Astrophysics Data System (ADS)

    Cox, S. F. J.; Briddon, P. R.; Jones, R.

    1991-02-01

    This paper brings together some current concepts concerning hydrogen states in semiconductors (illustrated with reference to silicon but quite generally applicable) and highlight certain findings of recent quantum electronic structure calculations for defect centres involving hydrogen and its isotopes. As regards muonium, the situation which held in the early μSR literature [1] is entirely reversed: the location and structure of Mu* are now well established [2], whereas the precise location and the nature of the metastability of Mu' have become open questions! In fact, neither state is stable in the presence of other electrically active impurities, which undoubtedly accounts for the difficulty in detecting paramagnetic protium. The implications for the interpretation of existing data, and for various possible future experiments, are examined.

  19. Analysis of LaNi{sub 4.25}Al{sub 0.75} (LANA.75) tritide after five years of tritium exposure

    SciTech Connect

    Wermer, J.R.; Holder, J.S.; Mosley, W.C.

    1993-09-01

    Tritium aging studies have shown that LaNi{sub 4.25}Al{sub 0.75} (LANA .75) tritide storage material undergoes significant degradation with tritium aging. After 5.4 years of dormant storage at full stoichiometry, which is considered a worst-case condition for this material, the performance is still acceptable for SRS tritium processing applications. The isotherms change, decreasing the desorption pressures, increasing the isotherm plateau slopes, and decreasing the total storage capacity. Eventually, the material will degrade with time to the point where it may no longer be useful for tritium processing applications. At the end of life, the tritium heel can be exchanged with protium or deuterium to produce a final material containing very little tritium.

  20. Tests of potential energy surfaces for H+CH4↔CH3+H2: Deuterium and muonium kinetic isotope effects for the forward and reverse reaction

    NASA Astrophysics Data System (ADS)

    Pu, Jingzhi; Truhlar, Donald G.

    2002-12-01

    In previous work, three implicit potential energy surfaces with specific reaction parameters (SRP), namely MPW60, MC-QCISD-SRP, and MCG3-SRP, were developed for the reaction CH4+H→CH3+H2. Forward reaction rate constants obtained by variational transition state theory with multidimensional tunneling (VTST/MT) dynamics calculations on these surfaces give good agreement with recently re-analyzed experimental results. In the present work, again employing VTST/MT, kinetic isotope effects (KIEs) for isotopic variants of the title reaction in both the forward and reverse directions are examined on these SRP surfaces. Various primary and secondary deuterium (D) kinetic isotope reactions are studied; we also calculated the KIE for the reaction between methane and muonium (Mu), which is an ultralight isotope of protium with the Mu/H mass ratio being 0.113. The results are compared with several sets of experimental studies. With the VTST/MT dynamical method and harmonic vibrations, the proposed surfaces predict the KIE quite well, probably within experimental error, for seven different isotopic combinations involving substitution of one to five deuteriums for protium. The calculations also reproduce quite well the high Arrhenius activation energy for Mu+CH4, and the KIE for muonium atom attack is correctly predicted to be inverse, but the predicted values of the Mu KIE over the experimental temperature range are 0.012-0.06 (without scaling force constants) or 0.021-0.09 (when the force constant of the making bond is scaled), whereas the experimental values in the same temperature range are 0.05-0.3. Several possible reasons for this are discussed.

  1. EFFECTS OF TRITIUM EXPOSURE ON UHMW-PE, PTFE, AND VESPEL

    SciTech Connect

    Clark, E; Kirk Shanahan, K

    2006-05-31

    Samples of three polymers, Ultra-High Molecular Weight Polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, also known as Teflon{reg_sign}), and Vespel{reg_sign} polyimide were exposed to 1 atmosphere of tritium gas at ambient temperature for varying times up to 2.3 years in closed containers. Sample mass and size measurements (to calculate density), spectra-colorimetry, dynamic mechanical analysis (DMA), and Fourier-transform infrared spectroscopy (FT-IR) were employed to characterize the effects of tritium exposure on these samples. Changes of the tritium exposure gas itself were characterized at the end of exposure by measuring total pressure and by mass spectroscopic analysis of the gas composition. None of the polymers exhibited significant changes of density. The color of initially white UHMW-PE and PTFE dramatically darkened to the eye and the color also significantly changed as measured by colorimetry. The bulk of UHMW-PE darkened just like the external surfaces, however the fracture surface of PTFE appeared white compared to the PTFE external surfaces. The white interior could have been formed while the sample was breaking or could reflect the extra tritium dose at the surface directly from the gas. The dynamic mechanical response of UHMW-PE was typical of radiation effects on polymers- an initial stiffening (increased storage modulus) and reduction of viscous behavior after three months exposure, followed by lowering of the storage modulus after one year exposure and longer. The storage modulus of PTFE increased through about nine months tritium exposure, then the samples became too weak to handle or test using DMA. Characterization of Vespel{reg_sign} using DMA was problematic--sample-to-sample variations were significant and no systematic change with tritium exposure could be discerned. Isotopic exchange and incorporation of tritium into UHMW-PE (exchanging for protium) and into PTFE (exchanging for fluorine) was observed by FT-IR using an attenuated

  2. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS

    SciTech Connect

    Clark, E.

    2011-09-22

    ethylene propylene diene monomer (EPDM)) have been exposed in closed containers to tritium gas initially at 1 atmosphere pressure. These studies have demonstrated the degradation of properties when exposed to tritium gas. Also, the radiolytic production of significant amounts of hydrogen has been observed for UHMW-PE and EPDM. The study documented in this report exposes two similar formulations of EPDM elastomer to gamma irradiation in a closed container backfilled with deuterium. Deuterium is chemically identical to protium and tritium, but allows the identification of protium that is radiolytically produced from the samples. The goal of this program is to compare and contrast the response of EPDM exposure to two different types of ionizing radiation in a similar chemical environment.

  3. Does Size Really Matter? The Steric Isotope Effect in a Supramolecular Host?Guest Exchange Reaction

    SciTech Connect

    Mugridge, Jeffrey; Bergman, Robert; Raymond, Kenneth

    2010-01-29

    Isotope effects (IEs), which arise from differences in zero point energies (ZPEs) between a parent and isotopically substituted bond, have been used extensively by chemists to probe molecular interactions and reactivity. Due to the anharmonicity of the C-H/D vibrational potential energy function and the lower ZPE of a C-D bond, the average C-D bond length is typically {approx}0.005 {angstrom} shorter than an equivalent C-H bond. It is this difference in size that is often invoked to explain the observation of secondary, inverse kinetic isotope effects (KIEs) in chemical processes which proceed through a sterically strained transition state. This so-called 'steric isotope effect' (SIE) has been observed in processes such as the racemization of ortho-substituted biphenyls[6] and phenanthrenes, ring flipping of cyclophanes, and more recently in the deslipping of rotaxanes, where substitution of the sterically less demanding deuterium for protium results in rate accelerations for these processes. Herein, we use deuterium substitution in a cationic guest molecule to probe the sensitivity limits of the guest exchange process from a highly-charged supramolecular host.

  4. A review of proton transfer reactions between various carbon-acids and amine bases in aprotic solvents

    NASA Astrophysics Data System (ADS)

    Jarczewski, Arnold; Hubbard, Colin D.

    2003-04-01

    The subject of proton transfer between carbon acids and nitrogen bases in aprotic solvents is reviewed. Equilibrium and rate constants that characterize such reactions are most often determined utilizing UV-visible spectrophotometry. At ambient temperature reaction rates are sufficiently rapid that fast reaction methods, for example, the stopped-flow and temperature-jump techniques are required in many cases. Variation of the properties of the donor and acceptor reaction pairs enables electronic and steric effects upon thermodynamic and kinetic parameters of proton transfer to be assessed. Determination of the kinetic isotope effect (KIE), i.e. k(protium)/ k(deuterium) led to the conclusion that, under certain circumstances and when the KIE is greater than seven, the proton undergoes reaction with a significant degree of quantum mechanical tunneling, consistent with a theoretical prediction advanced several decades earlier. In fact this aspect may be one of the most significant outgrowths of these studies. Many reactions have been characterized (by tunneling) but rarely are the reacting systems experimentally amenable to obtaining all the experimental criteria that support tunneling. Controversy that has arisen regarding treatment of experimental data and resulting conclusions from them is visited in this review. The structural nature of the product state of reaction is formulated based on spectroscopic evidence, in favorable cases, and probable structures of the transition state can be inferred.

  5. Modeling temperature dependent kinetic isotope effects for hydrogen transfer in a series of soybean lipoxygenase mutants: The effect of anharmonicity upon transfer distance

    NASA Astrophysics Data System (ADS)

    Meyer, Matthew P.; Klinman, Judith P.

    2005-12-01

    Soybean lipoxygenase-1 (SLO) catalyzes the oxidation of linoleic acid. The rate-limiting step in this transformation is the net abstraction of the pro-S hydrogen atom from the center of the 1,5-pentadienyl moiety in linoleic acid. The large deuterium kinetic isotope effect (KIE) for this step appears in the first order rate constant ( Dkcat = 81 ± 5 at T = 25 °C). Furthermore, the KIE and the rate for protium abstraction are weakly temperature dependent ( EA,D - EA,H = 0.9 ± 0.2 kcal/mol and EA,H = 2.1 ± 0.2 kcal/mol, respectively). Mutations at a hydrophobic site about 13 Å from the active site Fe(III), Ile 553, induce a marked temperature dependence that varies roughly in accordance with the degree to which the residue is changed in bulk from the wild type Ile. While the temperature dependence for these mutants varies from the wild type enzyme, the magnitude of the KIE at 25 °C is on the same order of magnitude. A hydrogen tunneling model [Kuznetsov, A.M., Ulstrup, J. Can. J. Chem. 77 (1999) 1085-1096] is utilized to model the KIE temperature profiles for the wild type SLO and each Ile 553 mutant. Hydrogenic wavefunctions are modeled using harmonic oscillators and Morse oscillators in order to explore the effects of anharmonicity upon computed kinetic observables used to characterize this hydrogen transfer.

  6. Development of advanced concepts for improved heavy water production technology. Tri-quarterly report, January 1-September 30, 1980

    SciTech Connect

    Aldridge, F.T.; Herman, I.P.; Marling, J.B.; Wood, L.L.

    1980-11-06

    Research into deuterium-from-protium isotope separation via both metal hydride chromatography and CO/sub 2/ laser multiple-photon dissociation (MPD) of trifluoromethane (CDF/sub 3//CHF/sub 3/) is discussed. Several new classes of alloy compositions, including Mg-rare earth, NiTi/sub x/, and (Ca+Ce,Zr,Ti)./sub 8//sup -/Ni/sub 4/Cu compounds, were evaluated for chromatograhic isotope separation; no tested alloy exhibited properties suitable for commercial deuterium separation. For deuterium separation by MPD of CDF/sub 3/, construction of a CO/sub 2/ laser system was completed that is capable of delivering either 2 nsec short pulses at a single wavelength or 200 nsec long pulses simulatneously at two different laser frequencies. The wavelength dependence of single-line multiple-photon dissociation probability of CDF/sub 3/ was measured, and is reported here. Deuterium separation by CO/sub 2/ laser photolysis of CDF/sub 3//CHF/sub 3/ near 10.3 ..mu.. using approx. 2 nsec pulses still appears to be a commercially viable process for heavy water production.

  7. Methods of studying the composition of the low-energy ion beams and the surface of deuterated-metal targets

    NASA Astrophysics Data System (ADS)

    Kuznetsov, S. I.; Dudkin, G. N.; Nechaev, B. A.; Bystritsky, I. D.

    2016-06-01

    To study the reactions between the light nuclei (dd, pd, d3He, d4He) with ultralow collision energies, there is a need to obtain the high-precision experimental results on the purity of the target surface saturated with the hydrogen isotopes (protium, deuterium) and on the number and composition of the accelerated particles falling on the target. To solve this problem, a method has been developed and tested for operational testing the quality of the vacuum system and the cleaning of the metal target surface saturated with deuterium. The paper also presents the measurement results for the true flow of the accelerated ions and neutrals of hydrogen (deuterium), using a multigrid electrostatic energy analyzer. The values of the ion and neutral components of the accelerated particle flow were received for the Hall ion source. The values of the secondary electron emission coefficients were determined for a number of the metal targets (Cu, Ti, Ta, Zr) in the range of the accelerated ion energies of 3-12 keV.

  8. EFFECTS OF TRITIUM GAS EXPOSURE ON EPDM ELASTOMER

    SciTech Connect

    Clark, E.

    2009-12-11

    Samples of four formulations of ethylene-propylene diene monomer (EPDM) elastomer were exposed to initially pure tritium gas at one atmosphere and ambient temperature for various times up to about 420 days in closed containers. Two formulations were carbon-black-filled commercial formulations, and two were the equivalent formulations without filler synthesized for this work. Tritium effects on the samples were characterized by measuring the sample volume, mass, flexibility, and dynamic mechanical properties and by noting changes in appearance. The glass transition temperature was determined by analysis of the dynamic mechanical properties. The glass transition temperature increased significantly with tritium exposure, and the unfilled formulations ceased to behave as elastomers after the longest tritium exposure. The filled formulations were more resistant to tritium exposure. Tritium exposure made all samples significantly stiffer and therefore much less able to form a reliable seal when employed as O-rings. No consistent change of volume or density was observed; there was a systematic lowering of sample mass with tritium exposure. In addition, the significant radiolytic production of gas, mainly protium (H{sub 2}) and HT, by the samples when exposed to tritium was characterized by measuring total pressure in the container at the end of each exposure and by mass spectroscopy of a gas sample at the end of each exposure. The total pressure in the containers more than doubled after {approx}420 days tritium exposure.

  9. Antimicrobial activity of some medicinal plants from the cerrado of the centralwestern region of Brazil.

    PubMed

    Violante, Ivana Maria Póvoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Batista, Ana Lucia; Chang, Marilene Rodrigues; Pott, Vali Joana; Garcez, Fernanda Rodrigues

    2012-10-01

    Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations. PMID:24031956

  10. Antimicrobial activity of some medicinal plants from the cerrado of the centralwestern region of Brazil

    PubMed Central

    Violante, Ivana Maria Póvoa; Hamerski, Lidilhone; Garcez, Walmir Silva; Batista, Ana Lucia; Chang, Marilene Rodrigues; Pott, Vali Joana; Garcez, Fernanda Rodrigues

    2012-01-01

    Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations. PMID:24031956

  11. Therapeutic switching: from antidermatophytic essential oils to new leishmanicidal products

    PubMed Central

    Houël, Emeline; Gonzalez, German; Bessière, Jean-Marie; Odonne, Guillaume; Eparvier, Véronique; Deharo, Eric; Stien, Didier

    2015-01-01

    This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC50) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC50: 4.7 µg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis. PMID:25742270

  12. Modeling tritium behavior in Li{sub 2}ZrO{sub 3}.

    SciTech Connect

    Billone, M. C.

    1998-01-13

    Lithium metazirconate (Li{sub 2}ZrO{sub 3}) is a promising tritium breeder material for fusion reactors because of its excellent tritium release characteristics. In particular, for water-cooled breeding blankets (e.g., ITER), Li{sub 2}ZrO{sub 3} is appealing from a design perspective because of its good tritium release at low operating temperatures. The steady-state and transient tritium release/retention database for Li{sub 2}ZrO{sub 3} is reviewed, along with conventional diffusion and first-order surface resorption models which have been used to match the database. A first-order surface resorption model is recommended in the current work both for best-estimate and conservative (i.e., inventory upper-bound) predictions. Model parameters we determined and validated for both types of predictions, although emphasis is placed on conservative design predictions. The effects on tritium retention of ceramic microstructure, protium partial pressure in the purge gas and purge gas flow rate are discussed, along with other mechanisms for tritium retention which may not be dominant in the experiments, but may be important in blanket design analyses. The proposed tritium retention/release model can be incorporated into a transient thermal performance code to enable whole-blanket predictions of tritium retention/release during cyclic reactor operation. Parameters for the ITER driver breeding blanket are used to generate a numerical set of model predictions for steady-state operation.

  13. Minimisation of the Hydrogenic Inventory of the ITER Neutral Beamline and Torus Cryo-Sorption Pumps

    SciTech Connect

    Wykes, M

    2005-07-15

    The tritium inventory of all the ITER torus cryopumps open to the vacuum vessel has an administrative limit of 120 g, including tritium bound to hydrocarbon compounds formed by combination of fuel gas with carbon plasma-facing components. The total hydrogenic inventory of each of the torus cryopumps has to be less than that resulting in a deflagration pressure of 0.2 MPa (the design pressure of the ITER vacuum vessel of which the torus and neutral beam cryopump pressure boundaries are a part) following a hydrogen-air ignition. Since the neutral beamline fuelling is with protium and deuterium only, these pumps do not significantly contribute to the 120 g tritium limit. The hydrogenic inventories of both the torus and neutral beam cryopumps add to the total for the vacuum vessel following an in-vessel ingress of coolant from a failed water-cooled component, wherein hydrogen is produced from steam reacting with hot metallic dust. There is therefore a large incentive to keep the peak inventories of both the torus and neutral beamline cryopumps as low as practicable. The paper describes the regeneration patterns of the torus and neutral beamline cryopumps that are used to attain this goal while achieving the required vacuum conditions commensurate with the reference ITER pulse scenarios.

  14. Tritium diffusion in V4Cr-4Ti alloy

    SciTech Connect

    Hashizume, K.; Masuda, J.; Otsuka, K. T.; Tanabe, T.; Hatano, Y.; Nakamura, Y.; Nagasaka, T.; Muroga, T.

    2008-07-15

    Characteristics of the tritium diffusion coefficient DT in V-4Cr-4Ti alloy, including a bending in the Arrhenius plot of DT, are examined. Based on a trap model, the possible trap sources and their binding energies for tritium in the alloy are evaluated using the experimental data of DT in pure V, which are measured with a tritium tracer method, and the literature data of protium diffusion in V-Ti and V-Cr alloys. The result of the evaluation suggests the presence of two trap sources in the alloy. The first would be attributed to a trap at each substitutional alloying atom which is likely to be Ti. The binding energy E{sub B} of 0.08 eV gives the best fit to the observed value of DT above 300 K The bending in the Arrhenius plot below 300 K is caused by a second trap site with a higher E and a lower concentration than those of each alloying atom. The trap is probably formed by the alloying atoms presence to neighboring Ti atoms. The contribution of Cr atom to the trap effect seems to be rather small in this alloy. (authors)

  15. Naturally occurring compounds affect glutamatergic neurotransmission in rat brain.

    PubMed

    Martini, Lucia Helena; Jung, Fernanda; Soares, Felix Antunes; Rotta, Liane Nanci; Vendite, Deusa Aparecida; Frizzo, Marcos Emilio dos Santos; Yunes, Rosendo A; Calixto, João Batista; Wofchuk, Susana; Souza, Diogo O

    2007-11-01

    Natural products, including those derived from plants, have largely contributed to the development of therapeutic drugs. Glutamate is the main excitatory neurotransmitter in the central nervous system and it is also considered a nociceptive neurotransmitter, by acting on peripheral nervous system. For this reason, in this study we investigated the effects of the hydroalcoholic extracts from Drymis winteri (polygodial and drimanial), Phyllanthus (rutin and quercetine), Jathopha elliptica (jatrophone), Hedyosmum brasiliense (13HDS), Ocotea suaveolens (Tormentic acid), Protium kleinii (alphabeta-amyrin), Citrus paradise (naringin), soybean (genistein) and Crataeva nurvala (lupeol), described as having antinociceptive effects, on glutamatergic transmission parameters, such as [(3)H]glutamate binding, [(3)H]glutamate uptake by synaptic vesicles and astrocyte cultures, and synaptosomal [(3)H]glutamate release. All the glutamatergic parameters were affected by one or more of these compounds. Specifically, drimanial and polygodial presented more broad and profound effects, requiring more investigation on their mechanisms. The putative central side effects of these compounds, via the glutamatergic system, are discussed. PMID:17577666

  16. EVALUATION OF ALTERNATE STAINLESS STEEL SURFACE TREATMENTS FOR MASS SPECTROSCOPY AND OTHER TRITIUM SYSTEMS

    SciTech Connect

    Clark, E.; Mauldin, C.; Neikirk, K.

    2012-02-29

    There are specific components in the SRS Tritium Facilities that are required to introduce as few chemical impurities (such as protium and methane) as possible into the process gas. Two such components are the inlet systems for the mass spectroscopy facilities and hydrogen isotope mix standard containers. Two vendors now passivate stainless steel components for these systems, and both are relatively small businesses whose future viability can be questioned, which creates the need for new sources. Stainless steel containers were designed to evaluate alternate surface treatment vendors for tritium storage and handling for these high purity tritium systems. Five vendors applied their own 'best' surface treatments to two containers each - one was a current vendor, another was a chemical vapor deposited silicon coating, and the other three were electropolishing and chemical cleaning vendors. Pure tritium gas was introduced into all ten containers and the composition was monitored over time. The only observed impurities in the gas were some HT, less CT{sub 4}, and very small amounts of T{sub 2}O in all cases. The currently used vendor treated containers contained the least impurities. The chemical vapor deposited silicon treatment resulted in the highest impurity levels. Sampling one set of containers after about one month of tritium exposure revealed the impurity level to be nearly the same as that after more than a year of exposure - this result suggests that cleaning new stainless steel components by tritium gas contact for about a month may be a worthy operation.

  17. Screening of Venezuelan medicinal plant extracts for cytostatic and cytotoxic activity against tumor cell lines.

    PubMed

    Taylor, Peter; Arsenak, Miriam; Abad, María Jesús; Fernández, Angel; Milano, Balentina; Gonto, Reina; Ruiz, Marie-Christine; Fraile, Silvia; Taylor, Sofía; Estrada, Omar; Michelangeli, Fabian

    2013-04-01

    There are estimated to be more than 20,000 species of plants in Venezuela, of which more than 1500 are used for medicinal purposes by indigenous and local communities. Only a relatively small proportion of these have been evaluated in terms of their potential as antitumor agents. In this study, we screened 308 extracts from 102 species for cytostatic and cytotoxic activity against a panel of six tumor cell lines using a 24-h sulphorhodamine B assay. Extracts from Clavija lancifolia, Hamelia patens, Piper san-vicentense, Physalis cordata, Jacaranda copaia, Heliotropium indicum, and Annona squamosa were the most cytotoxic, whereas other extracts from Calotropis gigantea, Hyptis dilatata, Chromolaena odorata, Siparuna guianensis, Jacaranda obtusifolia, Tapirira guianensis, Xylopia aromatica, Protium heptaphyllum, and Piper arboreum showed the greatest cytostatic activity. These results confirm previous reports on the cytotoxic activities of the above-mentioned plants as well as prompting further studies on others such as C. lancifolia and H. dilatata that have not been so extensively studied. PMID:22648665

  18. Nuclear particle decay in a multi-MeV beam ejected by pulsed-laser impact on ultra-dense hydrogen H(0)

    NASA Astrophysics Data System (ADS)

    Holmlid, Leif

    2015-10-01

    The multi-MeV particles ejected from pulsed laser-induced processes in ultra-dense hydrogen H(0) are observed in vacuum at three different distances up to 2m from the laser target. In previous publications, massive neutral particles with energy of 1-30MeVu-1 were identified. Direct energy spectra of the particles show energies well above 1MeV. The particles studied here interact with metallic collectors and give signals due to several processes like secondary electron emission and lepton pair production (published). Two experimental facts are immediate: (1) the signal per sr at large distance is up to 10 times higher than at short distance, (2) the signal at large distance is faster in real time than at short distance. These results show directly that the signal at long distance is mainly due to a mixture of intermediate particles formed by decay in the beam. The decaying signals have time constants of approximately 12 and 26ns for ultra-dense deuterium D(0) and 52 ns for ultra-dense protium p(0). These decay time constants agree well with those for decay of light mesons. These particles with narrow MeV energy distributions are formed by stepwise decay from particles like HN(0). The main result is that a decaying particle flux is formed by the laser-induced processes. The final muons produced may be useful for muon catalyzed fusion.

  19. Quantum states of hydrogen atom on Pd(1 1 0) surface

    NASA Astrophysics Data System (ADS)

    Padama, Allan Abraham B.; Nakanishi, Hiroshi; Kasai, Hideaki

    2015-12-01

    The quantum states of adsorbed hydrogen atom on Pd(1 1 0) surface are investigated in this work. From the calculated potential energy surface (PES) of hydrogen atom on Pd(1 1 0), the wave functions and eigenenergies in the ground and few excited states of protium (H) and deuterium (D) are calculated. Localized wave functions of hydrogen atom exist on pseudo-threefold and long bridge sites of Pd(1 1 0). The short bridge site is a local minimum from the result of PES, however, quantum behavior of hydrogen revealed that its vibration would allow it to hop to other pseudo-threefold site (that crosses the short bridge site) than to stay on the short bridge site. Exchange of ordering of the wave functions between H and D is attributed to the difference in their masses. The calculated eigenenergies are found to be in fair agreement with experimental data based from the identified vibrations of hydrogen with component perpendicular to the surface. The activation barriers measured from the eigenenergies are in better agreement with experimental findings in comparison to the data gathered from PES.

  20. Therapeutic switching: from antidermatophytic essential oils to new leishmanicidal products.

    PubMed

    Houël, Emeline; Gonzalez, German; Bessière, Jean-Marie; Odonne, Guillaume; Eparvier, Véronique; Deharo, Eric; Stien, Didier

    2015-02-01

    This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC50) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC50: 4.7 µg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis. PMID:25742270

  1. Blister formation on 13Cr2MoNbVB ferritic-martensitic steel exposed to hydrogen plasma

    NASA Astrophysics Data System (ADS)

    Nikitin, A. V.; Tolstolutskaya, G. D.; Ruzhytskyi, V. V.; Voyevodin, V. N.; Kopanets, I. E.; Karpov, S. A.; Vasilenko, R. L.; Garner, F. A.

    2016-09-01

    The influence of pre-irradiation specimen deformation level on surface blister formation and sub-surface cracking of dual-phase 13Cr2MoNbVB ferritic-martensitic steel was studied using glow discharge hydrogen plasma with ion energy of 1 keV to fluences of 2 × 1025 H/m2. Protium was used for most studies, but deuterium was used for measuring the depth dependence of hydrogen diffusion. Formation of blisters was observed in the temperature range 230-340 K. It was found that pre-irradiation deformation caused changes in the threshold fluences of blister formation and also in blister size distribution. Subsurface cracks located on grain boundaries far beyond the implantation zone were formed concurrently with blisters, arising from hydrogen diffusion and trapping at defects. It was observed that cracks as long as 1 mm in length were formed in 95% deformed steel at depths up to 500 μm from surface.

  2. Chemical and hydrogen isotope evidence for in situ dehydrogenation of biotite in silicic magma chambers

    NASA Astrophysics Data System (ADS)

    Feeley, T. C.; Sharp, Z. D.

    1996-11-01

    To examine the potential for volatile fluxing of magma chambers by in situ degassing of hydrous minerals, we obtained complete chemical analyses for biotite separates from silicic lavas. The separates exhibit unusually low H2O contents that inversely correlate with host lava temperatures, high Fe3+/Fe2+ ratios that inversely correlate with host lava oxygen fugacities, and the highest δ D values yet reported for biotite from any silicic igneous rock (up to -19‰). These results are direct evidence for selective loss of protium (1H) from biotite during dehydrogenation in magma chambers heated from below by intrusion of mafic magma. The maximum PΔV energy generated from dehydrogenation alone can approach 2 × 103 joules per kilogram of magma. This finding provides support for the concept that injection of mafic magma coupled with sudden degassing of hydrous minerals in a volatile-rich magma chamber can increase pressure, and thus enhance the possibility of initiating a volcanic eruption.

  3. Development of fusion fuel cycle technology at the tritium laboratory Karlsruhe: The experiment CAPRICE

    SciTech Connect

    Glugla, M.; Penzhorn, R.D.

    1994-12-31

    The development of plasma exhaust fuel clean-up technology for the recovery of chemically bonded and elemental tritium/deuterium isotopes based on catalytic processes involving the thermal decomposition of hydrocarbons and the reduction of water vapor by carbon monoxide (water gas shift reaction) in combination with hydrogen isotope permeation presently constitutes the main experimental activity at the Tritium Laboratory Karlsruhe (TLK). All basic steps of these processes have been tested with protium/deuterium under laboratory and technical scale conditions. In addition, the validity of the integral process concept has also been demonstrated with relevant concentrations of tritium in small scale runs performed in collaboration with TSTA, Los Alamos National Laboratory. A facility carrying the acronym CAPRICE (Catalytic: Purification Experiment) has been erected at the TLK to demonstrate the process assembly with tritium on a technical scale. The design throughput is approx. 10 mol/h of DT and about 1 mol/h of tritiated and untritiated impurities. Depending upon the selected process conditions within the fusion fuel cycle this throughput could actually approach the needs of ITER. These gloves boxes for the primary system and the containment for a 150 m{sup 3}/h scroll pump totaling a volume of 16.6 m{sup 3} are operated under an inert gas atmosphere (0.5-1% O{sub 2}) at slightly below laboratory pressure. Two tritium retention systems provide with four ionization chambers are employed to control the tritium activity in the glove box atmosphere.

  4. EXPERIMENTAL RESULTS FOR THE ISOTOPIC EXCHANGE OF A 1600 LITER TITANIUM HYDRIDE STORAGE VESSEL

    SciTech Connect

    Klein, J.

    2010-12-14

    Titanium is used as a low pressure tritium storage material. The absorption/desorption rates and temperature rise during air passivation have been reported previously for a 4400 gram prototype titanium hydride storage vessel (HSV). A desorption limit of roughly 0.25 Q/M was obtained when heating to 700 C which represents a significant residual tritium process vessel inventory. To prepare an HSV for disposal, batchwise isotopic exchange has been proposed to reduce the tritium content to acceptable levels. A prototype HSV was loaded with deuterium and exchanged with protium to determine the effectiveness of a batch-wise isotopic exchange process. A total of seven exchange cycles were performed. Gas samples were taken nominally at the beginning, middle, and end of each desorption cycle. Sample analyses showed the isotopic exchange process does not follow the standard dilution model commonly reported. Samples taken at the start of the desorption process were lower in deuterium (the gas to be removed) than those taken later in the desorption cycle. The results are explained in terms of incomplete mixing of the exchange gas in the low pressure hydride.

  5. Phase transition temperatures of 405-725 K in superfluid ultra-dense hydrogen clusters on metal surfaces

    NASA Astrophysics Data System (ADS)

    Holmlid, Leif; Kotzias, Bernhard

    2016-04-01

    Ultra-dense hydrogen H(0) with its typical H-H bond distance of 2.3 pm is superfluid at room temperature as expected for quantum fluids. It also shows a Meissner effect at room temperature, which indicates that a transition point to a non-superfluid state should exist above room temperature. This transition point is given by a disappearance of the superfluid long-chain clusters H2N(0). This transition point is now measured for several metal carrier surfaces at 405 - 725 K, using both ultra-dense protium p(0) and deuterium D(0). Clusters of ordinary Rydberg matter H(l) as well as small symmetric clusters H4(0) and H3(0) (which do not give a superfluid or superconductive phase) all still exist on the surface at high temperature. This shows directly that desorption or diffusion processes do not remove the long superfluid H2N(0) clusters. The two ultra-dense forms p(0) and D(0) have different transition temperatures under otherwise identical conditions. The transition point for p(0) is higher in temperature, which is unexpected.

  6. Wood litter consumption by three species of Nasutitermes termites in an area of the Atlantic Coastal Forest in northeastern Brazil.

    PubMed

    Vasconcellos, Alexandre; Moura, Flávia Maria da Silva

    2010-01-01

    Termites constitute a considerable fraction of the animal biomass in tropical forest, but little quantitative data are available that indicates their importance in the processes of wood decomposition. This study evaluated the participation of Nasutitermes corniger (Motschulsky) (Isoptera: Termitidae), N. ephratae (Holmgren), and N. macrocephalus (Silvestri) in the consumption of the wood litter in a remnant area of Atlantic Coastal Forest in northeastern Brazil. The populations of this species were quantified in nests and in decomposing tree trunks, while the rate of wood consumption was determined in the laboratory using wood test-blocks of Clitoria fairchildiana Howard (Fabales: Fabaceae), Cecropia sp. (Urticales: Cecropiaceae), and Protium heptaphyllum (Aublet) Marchand (Sapindales: Burseraceae). The abundance of the three species of termites varied from 40.8 to 462.2 individuals/m(2). The average dry wood consumption for the three species was 9.4 mg/g of termites (fresh weight)/day, with N. macrocephalus demonstrating the greatest consumption (12.1 mg/g of termite (fresh weight)/day). Wood consumption by the three species of Nasutitermes was estimated to be 66.9 kg of dry wood /ha/year, corresponding to approximately 2.9% of the annual production of wood-litter in the study area. This consumption, together with that of the other 18 exclusively wood-feeders termite species known to occur in the area, indicates the important participation of termites in removing wood-litter within the Atlantic Coastal Forest domain. PMID:20673190

  7. Antiprotozoal activities of Colombian plants.

    PubMed

    Weniger, B; Robledo, S; Arango, G J; Deharo, E; Aragón, R; Muñoz, V; Callapa, J; Lobstein, A; Anton, R

    2001-12-01

    In our search for therapeutical alternatives for antiprotozoal chemotherapy, we collected a selection of 44 plants from western Colombia upon ethnopharmacological and chemotaxonomic considerations. Polar and apolar extracts of these species were examined for antimalarial activity using in vitro tests with two clones of Plasmodium falciparum. Leishmanicidal and trypanocidal activity were determined in vitro using promastigote and amastigote forms of several strains of Leishmania sp. and epimastigotes of Trypanosoma cruzi. Among the selected plants, the 15 following species showed good or very good antiprotozoal activity in vitro: Aspidosperma megalocarpon, Campnosperma panamense, Conobea scoparioides, Guarea polymera, Guarea guidonia, Guatteria amplifolia, Huberodendron patinoi, Hygrophila guianensis, Jacaranda caucana, Marila laxiflora, Otoba novogranatensis, Otoba parviflora, Protium amplium, Swinglea glutinosa and Tabernaemontana obliqua. Cytotoxicity was assessed in U-937 cells and the ratio of cytotoxicity to antiprotozoal activity was determined for the active extracts. Ten extracts from eight species showed selectivity indexes > or = 10. Among the extracts that showed leishmanicidal activity, the methylene chloride extract of leaves from C. scoparioides showed a selectivity index in the same range that the one of the Glucantime control. Several of the active leishmanicidal plants are traditionally used against leishmaniasis by the population of the concerned area. PMID:11694364

  8. [Nesting biology of Centris flavifrons (Friese) (Hymenoptera: Apidae, Centridini), one of the main pollinators of Byrsonima crassifolia L. Kunth in Maranhão, Brazil].

    PubMed

    Rego, Márcia M C; Albuquerque, Patrícia M C; Ramos, Marina C; Carreira, Léa M

    2006-01-01

    The Centridini has almost 176 species distributed mainly in the tropic regions of America. Although they are considered key pollinators in the maintenance of many vegetal species, data about their bionomics are restrict. Nesting activity is known for 11 species, out of the 21 that are considered pollinators of murici, Byrsonima crassifolia L. Kunth, a valuable biomonitoring specie. A study of the nesting biology of Centris flavifrons (Friese) was conducted in the state of Maranhão, Brazil, during the active period of the adults (May through December). Nests were aggregated. The females excavated their nests on flat surfaces of hard soils. Fifteen nests were dug and we only found cells in six of them. The nests architecture consisted of a single unbranched tunnel, with only one cell in the vertical position at the end, which was 25 cm to 50 cm away from the entrance. Nocturnal activity was observed in the nests building. The pollen analysis of the contents of four cells allowed to identify 23 floral species, six of them Malpighiaceae. Six floral species were registered visiting C. flavifrons by the first time: Lecythis lurida (Miers) Mori, Hymenea courbaril L., Myrcea sp., Protium sp., Tetrapterys sp. and Thalisia sp. PMID:17144128

  9. Seasonal variations in the stable oxygen isotope ratio of wood cellulose reveal annual rings of trees in a Central Amazon terra firme forest.

    PubMed

    Ohashi, Shinta; Durgante, Flávia M; Kagawa, Akira; Kajimoto, Takuya; Trumbore, Susan E; Xu, Xiaomei; Ishizuka, Moriyoshi; Higuchi, Niro

    2016-03-01

    In Amazonian non-flooded forests with a moderate dry season, many trees do not form anatomically definite annual rings. Alternative indicators of annual rings, such as the oxygen (δ(18)Owc) and carbon stable isotope ratios of wood cellulose (δ(13)Cwc), have been proposed; however, their applicability in Amazonian forests remains unclear. We examined seasonal variations in the δ(18)Owc and δ(13)Cwc of three common species (Eschweilera coriacea, Iryanthera coriacea, and Protium hebetatum) in Manaus, Brazil (Central Amazon). E. coriacea was also sampled in two other regions to determine the synchronicity of the isotopic signals among different regions. The annual cyclicity of δ(18)Owc variation was cross-checked by (14)C dating. The δ(18)Owc showed distinct seasonal variations that matched the amplitude observed in the δ(18)O of precipitation, whereas seasonal δ(13)Cwc variations were less distinct in most cases. The δ(18)Owc variation patterns were similar within and between some individual trees in Manaus. However, the δ(18)Owc patterns of E. coriacea differed by region. The ages of some samples estimated from the δ(18)Owc cycles were offset from the ages estimated by (14)C dating. In the case of E. coriacea, this phenomenon suggested that missing or wedging rings may occur frequently even in well-grown individuals. Successful cross-dating may be facilitated by establishing δ(18)Owc master chronologies at both seasonal and inter-annual scales for tree species with distinct annual rings in each region. PMID:26621690

  10. Investigating Inner Sphere Reorganization via Secondary Kinetic Isotope Effects in the C–H Cleavage Reaction Catalyzed by Soybean Lipoxygenase: Tunneling in the Substrate Backbone as well as the Transferred Hydrogen

    PubMed Central

    Meyer, Matthew P.; Klinman, Judith P.

    2011-01-01

    This work describes the application of NMR to the measurement of secondary deuterium (2° 2H) and carbon-13 (13C) kinetic isotope effects (KIES) at positions 9 to 13 within the substrate linoleic acid (LA) of soybean lipoxygenase-1. The KIEs have been measured using linoleic acid labeled with either protium (11,11-h2-LA) or deuterium (11,11-d2-LA) at the reactive C11 position, which has been previously shown to yield a primary deuterium isotope effect of ca. 80. The conditions of measurement yield the intrinsic 2° 2H and 13C KIEs on kcat/Km directly for 11,11-d2-LA, whereas the values for the 2° 2H KIEs for 11,11-h2-LA are obtained after correction for a kinetic commitment. The pattern of the resulting 2° 2H and 13C isotope effects reveals values that lie far above those predicted from changes in local force constants. Additionally, many of the experimental values cannot be modeled by electronic effects, torsional strain, or the simple inclusion of a tunneling correction to the rate. Although previous studies have shown the importance of extensive tunneling for cleavage of the primary hydrogen at C11 of LA, the present findings can only be interpreted by extending the conclusion of non-classical behavior to the secondary hydrogens and carbons that flank the position undergoing C-H bond cleavage. A quantum mechanical method introduced by Buhks et al. [J. Phys. Chem. 85, 3763 (1981)] to model the inner sphere reorganization that accompanies electron transfer has been shown to be able to reproduce the scale of the 2° 2H KIEs. PMID:21192631

  11. Effect of administration of water enriched in O2 by injection or electrolysis on transcutaneous oxygen pressure in anesthetized pigs

    PubMed Central

    Charton, Antoine; Péronnet, François; Doutreleau, Stephane; Lonsdorfer, Evelyne; Klein, Alexis; Jimenez, Liliana; Geny, Bernard; Diemunsch, Pierre; Richard, Ruddy

    2014-01-01

    Background Oral administration of oxygenated water has been shown to improve blood oxygenation and could be an alternate way for oxygen (O2) supply. In this experiment, tissue oxygenation was compared in anesthetized pigs receiving a placebo or water enriched in O2 by injection or a new electrolytic process. Methods Forty-two pigs randomized in three groups received either mineral water as placebo or water enriched in O2 by injection or the electrolytic process (10 mL/kg in the stomach). Hemodynamic parameters, partial pressure of oxygen in the arterial blood (PaO2), skin blood flow, and tissue oxygenation (transcutaneous oxygen pressure, or TcPO2) were monitored during 90 minutes of general anesthesia. Absorption and tissue distribution of the three waters administered were assessed using dilution of deuterium oxide. Results Mean arterial pressure, heart rate, PaO2, arteriovenous oxygen difference, and water absorption from the gut were not significantly different among the three groups. The deuterium to protium ratio was also similar in the plasma, skin, and muscle at the end of the protocol. Skin blood flow decreased in the three groups. TcPO2 slowly decreased over the last 60 minutes of the experiment in the three groups, but when compared to the control group, the values remained significantly higher in animals that received the water enriched in O2 by electrolysis. Conclusions In this protocol, water enriched in O2 by electrolysis lessened the decline of peripheral tissue oxygenation. This observation is compatible with the claim that the electrolytic process generates water clathrates which trap O2 and facilitate O2 diffusion along pressure gradients. Potential applications of O2-enriched water include an alternate method of oxygen supply. PMID:25210438

  12. Hydrogen release from 800 MeV proton-irradiated tungsten

    NASA Astrophysics Data System (ADS)

    Oliver, B. M.; Venhaus, T. J.; Causey, R. A.; Garner, F. A.; Maloy, S. A.

    2002-12-01

    Tungsten irradiated in spallation neutron sources, such as those proposed for the accelerator production of tritium (APT) project, will contain large quantities of generated helium and hydrogen gas. Tungsten used in proposed fusion reactors will also be exposed to neutrons, and the generated protium will be accompanied by deuterium and tritium diffusing in from the plasma-facing surface. The release kinetics of these gases during various off-normal scenarios involving loss of coolant and after heat-induced rises in temperature are of particular interest for both applications. To determine the release kinetics of hydrogen from tungsten, tungsten rods irradiated with 800 MeV protons in the Los Alamos Neutron Science Center (LANSCE) to high exposures as part of the APT project have been examined. Hydrogen evolution from the tungsten has been measured using a dedicated mass-spectrometer system by subjecting the specimens to an essentially linear temperature ramp from ˜300 to ˜1500 K. Release profiles are compared with predictions obtained using the Tritium Migration Analysis Program (TMAP4). The measurements show that for high proton doses, the majority of the hydrogen is released gradually, starting at about 900 K and reaching a maximum at about 1400 K, where it drops fairly rapidly. Comparisons with TMAP show quite reasonable agreement using a trap energy of 1.4 eV and a trap density of ˜7%. There is a small additional release fraction occurring at ˜550 K, which is believed to be associated with low-energy trapping at or near the surface, and, therefore, was not included in the bulk TMAP model.

  13. Near Infrared Spectroscopy Facilitates Rapid Identification of Both Young and Mature Amazonian Tree Species

    PubMed Central

    Lang, Carla; Costa, Flávia Regina Capellotto; Camargo, José Luís Campana; Durgante, Flávia Machado; Vicentini, Alberto

    2015-01-01

    Precise identification of plant species requires a high level of knowledge by taxonomists and presence of reproductive material. This represents a major limitation for those working with seedlings and juveniles, which differ morphologically from adults and do not bear reproductive structures. Near-infrared spectroscopy (FT-NIR) has previously been shown to be effective in species discrimination of adult plants, so if young and adults have a similar spectral signature, discriminant functions based on FT-NIR spectra of adults can be used to identify leaves from young plants. We tested this with a sample of 419 plants in 13 Amazonian species from the genera Protium and Crepidospermum (Burseraceae). We obtained 12 spectral readings per plant, from adaxial and abaxial surfaces of dried leaves, and compared the rate of correct predictions of species with discriminant functions for different combinations of readings. We showed that the best models for predicting species in early developmental stages are those containing spectral data from both young and adult plants (98% correct predictions of external samples), but even using only adult spectra it is still possible to attain good levels of identification of young. We obtained an average of 75% correct identifications of young plants by discriminant equations based only on adults, when the most informative wavelengths were selected. Most species were accurately predicted (75–100% correct identifications), and only three had poor predictions (27–60%). These results were obtained despite the fact that spectra of young individuals were distinct from those of adults when species were analyzed individually. We concluded that FT-NIR has a high potential in the identification of species even at different ontogenetic stages, and that young plants can be identified based on spectra of adults with reasonable confidence. PMID:26312996

  14. Deuterium transfer from [1,1-2-H] ethanol during metabolism of bile acids and cyclohexanone in the isolated perfused rat liver.

    PubMed

    Cronholm, T; Eriksson, H; Matern, S; Sjövall, J

    1975-05-01

    Deuterium transfer from [1,1-2-H]ethanol (95 atoms % excess) to reducible substrates was studied in the isolated perfused rat liver. The dueterium excess in cyclohexanol formed from cyclohexanone was somewhat lower (49 atoms%) than found under conditions in vivo, and this was also true of the deuterium excess in lithocholic acid formed from 3-oxo-5beta-cholanoic acid. These results may reflect a slower rate of ethanol oxidation in the isolated organ than in vivo. Cycloserine decreased the dueterium transfer to both substrates, whereas addition of lactate and malate resulted in an increased deuterium excess in cyclohexanol and a decreased deuterium excess in lithocholic acid. Addition of heavy water to the perfusion fluid resulted in labelling at C-3 of lithocholic acid formed from 3-oxo-5beta-cholanoic acid, and at C-3, C-4 and C-5 of 3alpha-hydroxy-5alpha-cholanoic acid formed from 3-oxo-4-cholenoic acid. The deuterium excess of hydrogens derived from NADPH (at C-3 and C-5) was approximately the same as that of hydrogen derived directly from water (at C-4). Thus, the hydrogen of NADPH is extensively exchanged with protons of water, which explains the dilution of deuterium with protium during the transfer from [1,1-2-H]ethanol via NADPH to the bile acids. The labelling at C-5 in the reduction of the 4,5-double bond indicates that different pools of NADPH are used for reduction of this double bond and the 3-oxo group, since in a previous study it was shown that deuterium is transferred from [1,1-2-H]ethanol only in the latter reaction. PMID:1140194

  15. Plant Ontogeny, Spatial Distance, and Soil Type Influence Patterns of Relatedness in a Common Amazonian Tree

    PubMed Central

    Barbosa, Carlos Eduardo A.; Misiewicz, Tracy M.; Fine, Paul V. A.; Costa, Flávia R. C.

    2013-01-01

    The formation of spatial genetic structure (SGS) may originate from different patterns of seed deposition in the landscape, and is mostly determined by seed dispersal limitation. After dispersal, mechanisms such as filtering by environmental factors or attack by herbivores/pathogens throughout plant development stages, and potentially either disrupt or intensify SGS patterns. We investigated how the genotype of Protium subserratum (Burseraceae), a common tree species in the Ducke Reserve, Brazil, is distributed across the landscape. We used seven microsatellite markers to assess the SGS among plants at different life stages and in different environments. By quantifying the patterns of relatedness among plants of different sizes, we inferred the ontogenetic stage in which SGS changes occurred, and compared these effects across soil types. Relatedness among seedlings decreased when distance between seedlings increased, especially for the youngest seedlings. However, this trend was not continued by older plants, as relatedness values were higher among neighboring individuals of the juvenile and adult size class. Contrasting relatedness patterns between seedlings and larger individuals suggests a trade-off between the negative effects of being near closely-related adults (e.g. due to herbivore and pathogen attack) and the advantage of being in a site favorable to establishment. We also found that soil texture strongly influenced density-dependence patterns, as young seedlings in clay soils were more related to each other than were seedlings in bottomland sandy soils, suggesting that the mechanisms that create and maintain patterns of SGS within a population may interact with environmental heterogeneity. PMID:23667502

  16. Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria

    PubMed Central

    Osburn, Magdalena R.; Dawson, Katherine S.; Fogel, Marilyn L.; Sessions, Alex L.

    2016-01-01

    Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen—protium and deuterium—that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ2H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes. Here we report on the hydrogen isotopic fractionations of lipids produced by nitrate-respiring and sulfate-reducing bacteria. We observe only small differences in fractionation between oxygen- and nitrate-respiring growth conditions, with a typical pattern of variation between substrates that is broadly consistent with previously described trends. In contrast, fractionation by sulfate-reducing bacteria does not vary significantly between different substrates, even when autotrophic and heterotrophic growth conditions are compared. This result is in marked contrast to previously published observations and has significant implications for the interpretation of environmental hydrogen isotope data. We evaluate these trends in light of metabolic gene content of each strain, growth rate, and potential flux and reservoir-size effects of cellular hydrogen, but find no single variable that can account for the differences between nitrate- and sulfate-respiring bacteria. The emerging picture of bacterial hydrogen isotope fractionation is therefore more complex than the simple correspondence between δ2H and metabolic pathway previously understood from aerobes. Despite the complexity, the large signals and rich variability of observed lipid δ2H suggest much potential as an environmental recorder of metabolism. PMID:27531993

  17. Tritium handling and processing experience at TSTA

    SciTech Connect

    Anderson, J.L.; Okuno, K.

    1994-06-01

    In 1987, the Japan Atomic Energy Research Institute (JAERI) and the US Department of Energy (DOE) signed a collaborative agreement (Annex IV) for the joint funding and operation of the Tritium Systems Test Assembly (TSTA) at the Los Alamos National Laboratory (LANL) for a five year period ending June, 1992. After this initial five year collaboration, the Annex IV agreement was extended for another two year period ending June, 1994. During the first five years, a number of the integrated process loop tests of TSTA were conducted, as well as off-line testing of TSTA subsystems. During integrated loop testing the vacuum system, fuel cleanup systems, isotope separation system, transfer pumping system and gas analysis system, are interconnected and tested using 100 g-inventories of tritium to demonstrate steady-state operation of a tritium fuel processing cycle for a fusion reactor. These tests have resulted in a number of significant accomplishments and an experience data base on research, development and operation of the fuel processing system. One of the most significant accomplishments during the initial five year period was the continuous operation of the fuel processing loop for 25 days. During this 25-day extended operation, both the JAERI fuel cleanup system (J-FCU) and the original TSTA fuel cleanup system (FCU) were operated under similar conditions of flow, pressure, and impurity content of the DT gas. Both fuel cleanup systems were demonstrated to provide adequate impurity removal for plasma exhaust gas processing. The isotope separation system was operated continuously, producing pure tritium while rejecting protium as an impurity.

  18. Possibility of deuterium free water using as antitumoral means with reference to conditions of Martian expedition

    NASA Astrophysics Data System (ADS)

    Sinyak, Y.; Turusov, V.; Grigroriev, A.; Yaridze, D.; Gaidadimov, V.; Antoshina, E.; Gorkova, T.; Truhanova, L.

    The interplanetary space flights, Martian program as an example, will take place under conditions of increasing radiation level on crew. The search of methods for a decrease of oncologic risk produced by irradiation of astronauts, is one of the major factors of a successful implementation of a flight program. One of such methods is a usage by crew of potable water with the reduced concentrations of a heavy stable isotope of hydrogen - deuterium, which can be obtained in the regenerative life support systems. The heavy water (D2O) has toxic properties, distorting biochemical reactions in the cell, inhibiting process of DNA replication. It can be presumed that the replacement of deuterium in the water for protium will result in normalization of cell metabolism, reparation will take place and this will lead to the inhibition of tumour development. In this study the water with a decreased by 65% of deuterium was used. Antitumour properties of D 2-free water were studied with transplantable Lewis lung carcinoma in BDF1 strain of mice. First results show that average time of appearance of the first nodules at the site of transplantation was 14 % longer in mice fed D 2-free water as compared to control. The tumour volume in the experimental group (decreased content of D2 ) was always lower than in the control. Statistically significant differences in the tumour volume were registered at the 13, 15, 23, 26 and 28 -th days after transplantation. Inhibition of tumour growth was equal to 100% and 51% at the 5 th and 15-th days after- transplantation respectively. Increase of life span in the experimental group was 10%. The results indicate that the use by astronauts of water with decreased content of deuterium may decrease the risk of oncological diseases under conditions of high radiation level in the flight to Mars.

  19. Preparation of low HD contamination cells for the measurement of the triple point temperature of n-D/sub 2/

    SciTech Connect

    McConville, G.T.; Menke, D.A.; Pavese, F.

    1985-01-01

    An effort is under way to produce deuterium triple point sealed cells for a 18.7 K temperature reference point. Stability with time of impurity content in cells, namely HD, was found to be good from measurements made at IMGC since 1978, but nearly all commercially produced ''chemical pure'' D/sub 2/ contains approximately 0.5% HD. To reduce the HD content in the D/sub 2/ cell, two steps have been taken: (1) The stainless steel cell was chemically etched and then vacuum baked to remove Fe from the surface and to diffuse protium out of the cell. (2) The cell was flushed and filled to 70 bar with D/sub 2/ directly obtained from a thermal diffusion column with HD <70 ppM. Triple point measurements with the cell show an initial drift due to para-ortho conversion of 0.4 mK per hour decreasing to 0.7 mK per hour after 130 hours of conversion. The initial triple point temperature on NBS-IPTS-68 was found to be 18.732 +- 0.001 K; this agrees with the value found in the earlier IMGC cells, filled with commercial D/sub 2/, when the latter are corrected for a 0.4 +- 0.1 HD content, but the conversion in this cell was 10 times faster than in 304 stainless steel IMGC cells. Further measurements have been made using the clean n-D/sub 2/ in an unetched 304 stainless steel cell which has been flushed with D/sub 2/O vapor.

  20. Holocene History of the Chocó Rain Forest from Laguna Piusbi, Southern Pacific Lowlands of Colombia

    NASA Astrophysics Data System (ADS)

    Behling, Hermann; Hooghiemstra, Henry; Negret, Alvaro José

    1998-11-01

    A high-resolution pollen record from a 5-m-long sediment core from the closed-lake basin Laguna Piusbi in the southern Colombian Pacific lowlands of Chocó, dated by 11 AMS 14C dates that range from ca. 7670 to 220 14C yr B.P., represents the first Holocene record from the Chocó rain forest area. The interval between 7600 and 6100 14C yr B.P. (500-265 cm), composed of sandy clays that accumulated during the initial phase of lake formation, is almost barren of pollen. Fungal spores and the presence of herbs and disturbance taxa suggest the basin was at least temporarily inundated and the vegetation was open. The closed lake basin might have formed during an earthquake, probably about 4400 14C yr B.P. From the interval of about 6000 14C yr B.P. onwards, 200 different pollen and spore types were identified in the core, illustrating a diverse floristic composition of the local rain forest. Main taxa are Moraceae/Urticaceae, Cecropia,Melastomataceae/Combretaceae, Acalypha, Alchornea,Fabaceae, Mimosa, Piper, Protium, Sloanea, Euterpe/Geonoma, Socratea,and Wettinia.Little change took place during that time interval. Compared to the pollen records from the rain forests of the Colombian Amazon basin and adjacent savannas, the Chocó rain forest ecosystem has been very stable during the late Holocene. Paleoindians probably lived there at least since 3460 14C yr B.P. Evidence of agricultural activity, shown by cultivation of Zea maissurrounding the lake, spans the last 1710 yr. Past and present very moist climate and little human influence are important factors in maintaining the stable ecosystem and high biodiversity of the Chocó rain forest.

  1. Selection of a hydride former for the separation of hydrogen isotopes from inerts

    SciTech Connect

    Fisher, I.A.

    1990-01-01

    The properties of four hydride-forming materials have been investigated to determine their applicability for use in a process to separate hydrogen isotopes from inerts. These materials are Zr{sub 0.8}Ti{sub 0.2}Ni, Zr{sub 0.65}Ti{sub 0.35}Co, NdCo{sub 3}, and ErFe{sub 2}. The properties investigated while surveying these materials include ease of activation, isotherm characteristics, kinetics, cycling stability, and oxygen stability. The results of the survey indicate NdCo{sub 3} to be the hydride former of choice for use in the inert separation process. It is the most easily activated and has the most favorable isotherm characteristics (the largest usable capacity, flat plateaux, small hysteresis, and negligible heel) as well as the fastest absorption kinetics of the materials tested. NdCo{sub 3} also has good cycling and oxygen stability. As with most intermetallic alloys NdCo{sub 3} decrepitates into a fine powder after only a few sorption cycles in hydrogen and therefore must be consolidated in order to be used in the fixed-bed absorber envisioned for the inert separation process. Consolidation was achieved through support of the NdCo{sub 3} in a sinter-bonded aluminum matrix. Stable compacts of NdCo{sub 3} have been made consisting of 40 wt % Al in NdCo{sub 3} pellets, pressed at 27 kpsi, sintered under vacuum for 2 hr at 450{degree}C. These compacts retained the full absorptive capacity of NdCo{sub 3} and remained 99 wt % intact after 15 sorption cycles in protium. 16 refs., 9 figs.

  2. Tracers in recharge — Effects of partitioning in soils

    NASA Astrophysics Data System (ADS)

    Gerritse, Robert G.; Adeney, John A.

    1992-02-01

    Partitioning among mobile and stationary water phases in a soil measurably reduces movement of a tracer relative to the mobile water phase. The quantity of water infiltrating the soil, however, still follows from the product of the distance travelled by the tracer and average moisture content of the soil over that distance. Partitioning between surface and water phases in a soil by proton and protium exchange has only a small effect on the retention of isotopically labelled water. Partitioning between surface, water and gas phases in a soil, however, strongly decreases diffusive movement of isotopically labelled water in the gas phase. In sandy soils with moisture contents less than 5%, the effective diffusion coefficient in the gas phase can be reduced by a factor between 50 and 5000. As a soil dries out, diffusive movement of 18O labelled water will become larger than of HDO and HTO. Negative charges on soil surfaces repel chloride and bromide. The effect of charge exclusion on movement of Cl - and Br - relative to HDO was measured in small columns for a number of soils from the southwest of Western Australia. Data from these experiments show that in the unsaturated zone of sandy soils, charge exclusion can reduce the pore volume available to Cl - and Br - in the water phase at field capacity by > 20%. Recharge to ground water, if calculated from the position of Cl - or Br - tracers and average moisture in the soil profile, must then be reduced by the same percentage. The effect of charge exclusion in soils on the calculation of recharge from profile data, was evaluated for a practical situation. Significant amounts of bromide from car exhaust gases accumulate in soils in urban areas and can be used to trace water movement. A site was chosen in metropolitan Perth on a sparsely vegetated calcareous sand near the junction of two busy roads. A seasonal effect on bromide accumulation in the soil profile at this site was clearly visible from data on the soil solution

  3. Exploratory study of coal-conversion chemistry. Quarterly report No. 3, November 19, 1981-February 18, 1982. [Dihydronaphthalene, 1,2'-dinaphthylmethane, methoxynaphthalene diphenyl ether

    SciTech Connect

    Ross, D.S.; McMillen, D.F.; Ogier, W.C.; Bunnell, R.; Hum, G.P.

    1982-03-01

    Work in Task A has provided additional data on the rate and mechanisms of radical-induced cleavage of strong C-C and C-0 bonds in coal structures. This work has shown that even resonance-stabilized radicals, which form relatively weak C-C bonds, can displace other resonance-stabilized radicals from methylene-bridged coal structures. Kinetic studies reveal that either the self-disproportionation of 1,2-dihydronaphthalene is much faster than previously reported or that the 1,2-dihydronaphthalene-tetralin disproportionation is much less important as a radical initiation process than thermochemical estimates had suggested. 1,2'-Dinaphthylmethane undergoes radical-induced CH/sub 2/-Ar bond scission ten times faster than diphenyl ether. This factor is shown to be consistent with the thermochemistry of displacement by tetralyl radical. In Task B we studied CO/H/sub 2/O conversion of a second, high volatile bituminous coal, PSOC-233. We found that, as with PSOC-026, the initial pH did affect the conversion rate, increasing with higher pH. We also conducted experiments with several oxygen-containing model compounds in CO/D/sub 2/O at 400/sup 0/C for 20 min. We had shown earlier in preliminary control experiments that simple aromatics, such as toluene, did not incorporate deuterium under these conditions. This quarter we found that anisole (Ph-O-CH/sub 3/) was converted to several products, with benzene as the most prominent. About 60% of the anisole was recovered in several experiments with mass balances at about 85%. There was a net incorporation of deuterium in the product benzene. The corresponding conversion in tetralin under the same conditions was two orders of magnitude slower and yielded phenol as the major product. We conclude that in the aqueous medium a chain process can occur that yields phenyl radical, which can then receive protium from a starting anisole or deuterium from the mineral medium.

  4. Spectroscopic and computational studies of reduction of the metalversus the tetrapyrrole ring of coenzyme F-430 from methyl-coenzyme Mreductase

    SciTech Connect

    Dey, Mishtu; Kunz, Ryan C.; van Heuvelen, Katherine M.; Craft,Jennifer L.; Horng, Yih-Chern; Tang, Qun; Bocian, David F.; George, SimonJ.; Brunold, Thomas C.; Ragsdale, Stephen W.

    2006-06-30

    Methyl-coenzyme M reductase (MCR) catalyzes the final stepin methane biosynthesis by methanogenic archaea and contains aredox-active nickel tetrahydrocorphin, coenzyme F430, at its active site.Spectroscopic and computational methods have been used to study a novelform of the coenzyme, called F330, which is obtained by reducing F430with sodium borohydride (NaBH4). F330 exhibits a prominent absorptionpeak at 330 nm, which is blue shifted by 100 nm relative to F430. Massspectrometric studies demonstrate that the tetrapyrrole ring in F330 hasundergone reduction, on the basis of the incorporation of protium (ordeuterium), upon treatment of F430 with NaBH4 (or NaBD4). One- andtwo-dimensional NMR studies show that the site of reduction is theexocyclic ketone group of the tetrahydrocorphin. Resonance Raman studiesindicate that elimination of this pibond increases the overall pi-bondorder in the conjugative framework. X-ray absorption, magnetic circulardichroism, and computational results show that F330 contains low-spinNi(II). Thus, conversion of F430 to F330 reduces the hydrocorphin ringbut not the metal. Conversely, reduction of F430 with Ti(III) citrate togenerate F380 (corresponding to the active MCRred1 state) reduces theNi(II) to Ni(I) but does not reduce the tetrapyrrole ring system, whichis consistent with other studies [Piskorski, R., and Jaun, B. (2003) J.Am. Chem. Soc. 125, 13120-13125; Craft, J. L., et al. (2004) J. Biol.Inorg. Chem. 9, 77-89]. The distinct origins of the absorption bandshifts associated with the formation of F330 and F380 are discussedwithin the framework of our computational results. These studies on thenature of the product(s) of reduction of F430 are of interest in thecontext of the mechanism of methane formation by MCR and in relation tothe chemistry of hydroporphinoid systems in general. The spectroscopicand time-dependent DFT calculations add important insight into theelectronic structure of the nickel hydrocorphinate in its Ni(II) and

  5. [Determination of deuterium concentration in foods and influence of water with modified isotopic composition on oxidation parameters and heavy hydrogen isotopes content in experimental animals].

    PubMed

    Basov, A A; Bykov, I M; Baryshev, M G; Dzhimak, S S; Bykov, M I

    2014-01-01

    The article presents the results of the study of the deuterium (D) content in food products as well as the influence of deuterium depleted water (DDW) on the concentration of heavy hydrogen isotopes in the blood and lyophilized tissues of rats. The most significant difference in the content of D was found between potato and pork fat, which indexes the standard delta notation (δ) D in promille, related to the international standard SMOW (Standard Mean Ocean of Water) amounted to -83,2 per thousand and -250,7 per thousand, respectively (p<0,05). Among the investigated samples of water deuterium concentration ranged from -75,5 per thousand (Narzan) to +72,1 per thousand (Kubai), that indicates the ability of some food products to increase the concentration of heavy hydrogen atoms in the body. The data obtained in the experimental modeling of the diet of male Wistar rats in the age of 5-6 mo (weight 235 ± 16 g) using DDW (δD = -743,2 per thousand) instead of drinking water (δD = -37,0 per thousand) with identical mineral composition showed that after 2 weeks significant (p <0,05) formation of isotopic (deuterium-protium, D/H) gradient in the body is possible. Changing the direction of isotopic D/H gradient in laboratory animals in comparison with its physiological indicators (72-127 per thousand, "plasma>tissue") is due to different rates ofisotopic exchange reactions in plasma and tissues (liver, kidney, heart), which can be explained by entering into the composition of a modified diet of organic substrates with more than DDW concentration D, which are involved in the construction of cellular structures and eventually lead to a redistribution of D and change direction of D/H gradient "plasma

  6. Hydraulic redistribution in three Amazonian trees.

    PubMed

    Oliveira, Rafael S; Dawson, Todd E; Burgess, Stephen S O; Nepstad, Daniel C

    2005-09-01

    About half of the Amazon rainforest is subject to seasonal droughts of 3 months or more. Despite this drought, several studies have shown that these forests, under a strongly seasonal climate, do not exhibit significant water stress during the dry season. In addition to deep soil water uptake, another contributing explanation for the absence of plant water stress during drought is the process of hydraulic redistribution; the nocturnal transfer of water by roots from moist to dry regions of the soil profile. Here, we present data on patterns of soil moisture and sap flow in roots of three dimorphic-rooted species in the Tapajós Forest, Amazônia, which demonstrate both upward (hydraulic lift) and downward hydraulic redistribution. We measured sap flow in lateral and tap roots of our three study species over a 2-year period using the heat ratio method, a sap-flow technique that allows bi-directional measurement of water flow. On certain nights during the dry season, reverse or acropetal flow (i.e.,in the direction of the soil) in the lateral roots and positive or basipetal sap flow (toward the plant) in the tap roots of Coussarea racemosa (caferana), Manilkara huberi (maçaranduba) and Protium robustum (breu) were observed, a pattern consistent with upward hydraulic redistribution (hydraulic lift). With the onset of heavy rains, this pattern reversed, with continuous night-time acropetal sap flow in the tap root and basipetal sap flow in lateral roots, indicating water movement from wet top soil to dry deeper soils (downward hydraulic redistribution). Both patterns were present in trees within a rainfall exclusion plot (Seca Floresta) and to a more limited extent in the control plot. Although hydraulic redistribution has traditionally been associated with arid or strongly seasonal environments, our findings now suggest that it is important in ameliorating water stress and improving rain infiltration in Amazonian rainforests. This has broad implications for

  7. Stable isotope dilution assays of alternariol and alternariol monomethyl ether in beverages.

    PubMed

    Asam, Stefan; Konitzer, Katharina; Schieberle, Peter; Rychlik, Michael

    2009-06-24

    Stable isotope dilution assays (SIDAs) for the determination of the most important mycotoxins of the black mold Alternaria, namely, alternariol and alternariol monomethyl ether, have been developed. For this purpose, deuterated alternariol and alternariol methyl ether were synthesized by palladium catalyzed protium-deuterium exchange from the unlabeled toxins. Reaction conditions were chosen in such a manner that the formation of the [(2)H(4)]-isotopologues was favored. The synthesized products were characterized by LC-MS, NMR, and UV-spectroscopy. On the basis of the use of [(2)H(4)]-alternariol and [(2)H(4)]-alternariol methyl ether as internal standards, SIDAs were developed and applied to the determination of alternariol and alternariol methyl ether in beverages using LC-MS/MS. Method validation revealed a high sensitivity, i.e., low limits of detection (alternariol, 0.03 microg/kg; alternariol methyl ether, 0.01 microg/kg) and limits of quantitation (alternariol, 0.09 microg/kg; alternariol methyl ether, 0.03 microg/kg), respectively. Recovery from spiked apple juice was 100.5 +/- 3.4% for alternariol (range 0.1-1 microg/kg) and 107.3 +/- 1.6% for alternariol methyl ether (range 0.05-0.5 microg/kg). Interassay precision (expressed as coefficient of variation, CEV) for alternariol was 4.0% (7.82 +/- 0.31 microg/kg; vegetable juice, naturally contaminated) and 4.6% (1.04 +/- 0.05 microg/kg; grape juice, naturally contaminated). For alternariol methyl ether, a CEV of 2.3% (0.79 +/- 0.02 microg/kg; vegetable juice, naturally contaminated) was obtained. Analysis of fruit juices showed low contamination with alternariol and alternariol methyl ether in general, but higher values of both toxins were found in wine and vegetable juices. The values for alternariol were higher than those for alternariol methyl ether in nearly any case. However, the developed SIDA has proven to be optimally suited for further studies on alternariol and alternariol methyl ether content in

  8. Chemical and Hydrogen Isotope Compositions of Amphibole Phenocrysts in 1980 - 1986 and 2005 Mount St. Helens Eruption Products

    NASA Astrophysics Data System (ADS)

    Underwood, S. J.; Feeley, T. C.

    2006-12-01

    To better understand transient disequilibria processes in the shallow volcanic plumbing system beneath Mount St. Helens immediately prior to and during the eruptive phases of 1980 - 1986 and 2005, we determined chemical compositions and deuterium/protium (D/H) ratios of amphibole phenocrysts from dacitic volcanic rocks. The sample suite includes: (1) May 18, 1980, lateral blast lithic blocks representing the pre-eruptive cryptodome, white pumice lapilli in the Plinian fallout deposit and pumice blocks in pyroclastic flow deposits; (2) pumiceous and lithic blocks from pyroclastic flow deposits emplaced between June - October 1980; (3) 1982 - 1986 dome lavas; (4) gabbroic inclusions and (5) 2005 dome dacite. In addition, groundmass D/H ratios and water contents were determined where possible and magmatic temperatures and oxygen fugacities for samples were derived from electron microprobe analyses of coexisting Fe-Ti oxides. Key results include the following: (1) The rapid ascent and quench upon eruption of the May 18, 1980, white pumice preserved pristine phenocryst amphibole δD and water contents [baseline δDVSMOW = -57 ‰, 2 wt. % H2O]; trajectories formed by amphibole phenocrysts in rocks from succeeding eruptions project to this composition through at least 2005. (2) Shallow storage of the 1980 cryptodome magma over several weeks prior to May 18 resulted in lower amphibole δD values (-80 to -70 ‰) and water contents (1.6 wt.%) principally via dehydration. (3) Magmatic degassing resulted in dramatic isotopic disequilibrium between amphibole phenocrysts and groundmass δD. Some groundmass samples also show significant rehydration from contact with meteoric water. (4) Amphibole phenocrysts from pyroclastic flow deposits erupted in the mid- to late afternoon of May 18, 1980, have elevated δD values and Fe3+/Fe2+ ratios and lower water contents as the dehydroxylation process of dehydrogenation first appears. The magnitude of dehydrogenation intensifies (up to