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Chialian Tseng - One of the best experts on this subject based on the ideXlab platform.

  • preoconcentration of Nickel 63 in sea water for liwuid scintillation counting
    Analytica Chimica Acta, 1993
    Co-Authors: Jemmau Lo, Borjen Cheng, Chialian Tseng
    Abstract:

    Abstract A preconcentation procedure for enriching 63 Ni from sea water for measurement by liquid scintillation counting (LSC) was established. 63 Ni was first enriched by adsorption on hydrous magnesium oxide. The precipitate was collected and dissolved in concentrated HCl. 63 Ni was separated from the HCl solution by exctraction with diethyldithiocarbamate in chloroform followed by back-extraction into Au 3+ solution. Finally, 63 Ni in the Au 3+ LSC. The optimum conditions of the above preconcentration procedure were investigated by means of an r -emitter, 65 Ni, instead of 63 Ni, which is a weak β-emitter, as a radioactive tracer. The preconcentration procedure was applied in conjunction with LSC to the analysis of a 63 Ni-containing simulated sea-water sample and was found to be feasible and practical.

Jemmau Lo - One of the best experts on this subject based on the ideXlab platform.

  • preoconcentration of Nickel 63 in sea water for liwuid scintillation counting
    Analytica Chimica Acta, 1993
    Co-Authors: Jemmau Lo, Borjen Cheng, Chialian Tseng
    Abstract:

    Abstract A preconcentation procedure for enriching 63 Ni from sea water for measurement by liquid scintillation counting (LSC) was established. 63 Ni was first enriched by adsorption on hydrous magnesium oxide. The precipitate was collected and dissolved in concentrated HCl. 63 Ni was separated from the HCl solution by exctraction with diethyldithiocarbamate in chloroform followed by back-extraction into Au 3+ solution. Finally, 63 Ni in the Au 3+ LSC. The optimum conditions of the above preconcentration procedure were investigated by means of an r -emitter, 65 Ni, instead of 63 Ni, which is a weak β-emitter, as a radioactive tracer. The preconcentration procedure was applied in conjunction with LSC to the analysis of a 63 Ni-containing simulated sea-water sample and was found to be feasible and practical.

Borjen Cheng - One of the best experts on this subject based on the ideXlab platform.

  • preoconcentration of Nickel 63 in sea water for liwuid scintillation counting
    Analytica Chimica Acta, 1993
    Co-Authors: Jemmau Lo, Borjen Cheng, Chialian Tseng
    Abstract:

    Abstract A preconcentation procedure for enriching 63 Ni from sea water for measurement by liquid scintillation counting (LSC) was established. 63 Ni was first enriched by adsorption on hydrous magnesium oxide. The precipitate was collected and dissolved in concentrated HCl. 63 Ni was separated from the HCl solution by exctraction with diethyldithiocarbamate in chloroform followed by back-extraction into Au 3+ solution. Finally, 63 Ni in the Au 3+ LSC. The optimum conditions of the above preconcentration procedure were investigated by means of an r -emitter, 65 Ni, instead of 63 Ni, which is a weak β-emitter, as a radioactive tracer. The preconcentration procedure was applied in conjunction with LSC to the analysis of a 63 Ni-containing simulated sea-water sample and was found to be feasible and practical.

Philippe Jourand - One of the best experts on this subject based on the ideXlab platform.

  • Rhizosphere bacteria of Costularia spp. from ultramafic soils in New Caledonia: diversity, tolerance to extreme edaphic conditions, and role in plant growth and mineral nutrition
    Canadian Journal of Microbiology, 2013
    Co-Authors: Mathieu Gonin, Alexandre Lagrange, Simon Gensous, Hamid Amir, Marc Ducousso, Philippe Jourand
    Abstract:

    Rhizosphere bacteria were isolated from Costularia spp., pioneer sedges from ultramafic soils in New Caledonia, which is a hotspot of biodiversity in the South Pacific. Genus identification, ability to tolerate edaphic constraints, and plant-growth- promoting (PGP) properties were analysed. We found that 105 colony-forming units per gram of root were dominated by Proteobacteria (69%) and comprised 21 genera, including Burkholderia (28%), Curtobacterium (15%), Bradyrhizobium (9%), Sphingomonas (8%), Rhizobium (7%), and Bacillus (5%). High proportions of bacteria tolerated many elements of the extreme edaphic conditions: 82% tolerated 100 ?mol·L–1 chromium, 70% 1 mmol·L–1 Nickel, 63% 10 mmol·L–1 manganese, 24% 1 mmol·L–1 cobalt, and 42% an unbalanced calcium/magnesium ratio (1/16). These strains also exhibited multiple PGP properties, including the ability to produce ammonia (65%), indole-3-acetic acid (60%), siderophores (52%), and 1-aminocyclopropane-1-carboxylate (ACC) deaminase (39%); as well as the capacity to solubilize phosphates (19%). The best-performing strains were inoculated with Sorghum sp. grown on ultramafic substrate. Three strains significantly enhanced the shoot biomass by up to 33%. The most successful strains influenced plant nutrition through the mobilization of metals in roots and a reduction of metal transfer to shoots. These results suggest a key role of these bacteria in plant growth, nutrition, and adaptation to the ultramafic constraints. Key

  • Rhizosphere bacteria of Costularia spp. from ultramafic soils in New Caledonia: diversity, tolerance to extreme edaphic conditions, and role in plant growth and mineral nutrition.
    Canadian Journal of Microbiology, 2012
    Co-Authors: Mathieu Gonin, Alexandre Lagrange, Simon Gensous, Hamid Amir, Marc Ducousso, Philippe Jourand
    Abstract:

    Rhizosphere bacteria were isolated from Costularia spp., pioneer sedges from ultramafic soils in New Caledonia, which is a hotspot of biodiversity in the South Pacific. Genus identification, ability to tolerate edaphic constraints, and plant-growth-promoting (PGP) properties were analysed. We found that 105 colony-forming units per gram of root were dominated by Proteobacteria (69%) and comprised 21 genera, including Burkholderia (28%), Curtobacterium (15%), Bradyrhizobium (9%), Sphingomonas (8%), Rhizobium (7%), and Bacillus (5%). High proportions of bacteria tolerated many elements of the extreme edaphic conditions: 82% tolerated 100 μmol·L–1 chromium, 70% 1 mmol·L–1 Nickel, 63% 10 mmol·L–1 manganese, 24% 1 mmol·L–1 cobalt, and 42% an unbalanced calcium/magnesium ratio (1/16). These strains also exhibited multiple PGP properties, including the ability to produce ammonia (65%), indole-3-acetic acid (60%), siderophores (52%), and 1-aminocyclopropane-1-carboxylate (ACC) deaminase (39%); as well as the capa...

Jiri Janata - One of the best experts on this subject based on the ideXlab platform.

  • use of a microscope stage mounted Nickel 63 microirradiator for real time observation of the dna double strand break response
    Nucleic Acids Research, 2010
    Co-Authors: Wendy Kuhne, Jennifer L Steeb, Mark A Merkley, Yunfeng Zhou, Jiri Janata, William S Dynan
    Abstract:

    : Eukaryotic cells begin to assemble discrete, nucleoplasmic repair foci within seconds after the onset of exposure to ionizing radiation. Real-time imaging of this assembly has the potential to further our understanding of the effects of medical and environmental radiation exposure. Here, we describe a microirradiation system for targeted delivery of ionizing radiation to individual cells without the need for specialized facilities. The system consists of a 25-micron diameter electroplated Nickel-63 electrode, enveloped in a glass capillary and mounted in a micromanipulator. Because of the low energy of the beta radiation and the minute total amount of isotope present on the tip, the device can be safely handled with minimum precautions. We demonstrate the use of this system for tracking assembly of individual repair foci in real time in live U2OS human osteosarcoma cells. Results indicate that there is a subset of foci that appear and disappear rapidly, before a plateau level is reached approximately 30 min post-exposure. This subset of foci would not have been evident without real-time observation. The development of a microirradiation system that is compatible with a standard biomedical laboratory expands the potential for real-time investigation of the biological effects of ionizing radiation.

  • Nickel 63 microirradiators
    Analytical Chemistry, 2009
    Co-Authors: Jennifer L Steeb, Mira Josowicz, Jiri Janata
    Abstract:

    Here we report the fabrication of two types of microirradiators, consisting of a recessed disk and protruding wire with low-β-energy radionuclide Ni-63 electrodeposited onto a 25 μm diameter Pt wire. Ni-63 is constricted to a small surface area of the microelectrode; hence, this tool provides a means of delivery of localized, large dose density of β radiation to the object but a minimal dose exposure to the user. The activity levels of Ni-63 emitted from the recessed disk and protruding wire are 0.25 and 1 Bq, respectively. The corresponding β particles flux levels emitted from the recessed disk and protruding wire are 51 and 11 kBq/cm2, respectively. These values, measured experimentally using liquid scintillation counting, fit very well the expected values of activity for each microirradiator, calculated considering the self-absorption effect, typical for low-energy β particles. In order to determine the optimal configuration the dose rates for varying distances from the object were calculated.