The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

G Venkateswaran - One of the best experts on this subject based on the ideXlab platform.

  • direct determination of uranium in seawater by laser Fluorimetry
    Talanta, 2008
    Co-Authors: Sanjukta A Kumar, Niyoti Shenoy, Shailaja P Pandey, Suvarna Sounderajan, G Venkateswaran
    Abstract:

    A method for estimation of uranium in seawater by using steady state laser flourimetry is described. Uranium present in seawater, in concentration of approximately 3 ng ml(-1) was estimated without prior separation of matrix. Quenching effect of major ions (Cl(-), Na(+), SO(4)(-), Mg(+), Ca(+), K(+), HCO(3)(-), Br(-)) present in seawater on fluorescence intensity of uranium was studied. The concentration of phosphoric acid required for maximum enhancement of fluorescence intensity was optimized and was found to be 5%. Similarly the volume of concentrated nitric acid required to eliminate the quenching effect of chloride and bromide completely from 5 ml of seawater were optimized and was found to be 3 ml. A simple equation was derived using steady state fluorescence correction method and was used for calculation of uranium concentration in seawater samples. The method has a precesion of 1% (1s, n=3). The values obtained from laser Fluorimetry were validated by analyzing the same samples by linear sweep adsorptive stripping voltametry (LSASV) of the uranium-chloranilic acid (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) complex. Both the values are well in agreement.

Sanjukta A Kumar - One of the best experts on this subject based on the ideXlab platform.

  • direct determination of uranium in seawater by laser Fluorimetry
    Talanta, 2008
    Co-Authors: Sanjukta A Kumar, Niyoti Shenoy, Shailaja P Pandey, Suvarna Sounderajan, G Venkateswaran
    Abstract:

    A method for estimation of uranium in seawater by using steady state laser flourimetry is described. Uranium present in seawater, in concentration of approximately 3 ng ml(-1) was estimated without prior separation of matrix. Quenching effect of major ions (Cl(-), Na(+), SO(4)(-), Mg(+), Ca(+), K(+), HCO(3)(-), Br(-)) present in seawater on fluorescence intensity of uranium was studied. The concentration of phosphoric acid required for maximum enhancement of fluorescence intensity was optimized and was found to be 5%. Similarly the volume of concentrated nitric acid required to eliminate the quenching effect of chloride and bromide completely from 5 ml of seawater were optimized and was found to be 3 ml. A simple equation was derived using steady state fluorescence correction method and was used for calculation of uranium concentration in seawater samples. The method has a precesion of 1% (1s, n=3). The values obtained from laser Fluorimetry were validated by analyzing the same samples by linear sweep adsorptive stripping voltametry (LSASV) of the uranium-chloranilic acid (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) complex. Both the values are well in agreement.

Gerwin J. Puppels - One of the best experts on this subject based on the ideXlab platform.

  • Pretransplantation assessment of renal viability with NADH Fluorimetry.
    Kidney international, 2000
    Co-Authors: J. M. C. C. Coremans, Matthijs Van Aken, Daniëlle C.w.h. Naus, Marie-louise F Van Velthuysen, Hajo A. Bruining, Gerwin J. Puppels
    Abstract:

    Pretransplantation assessment of renal viability with NADH Fluorimetry. Background A pathophysiologic feature possibly involved in ischemic injury in transplant kidneys is mitochondrial dysfunction caused by disintegration of oxidative metabolic pathways. Because the ability to synthesize ATP by respiratory activity determines the organ's capacity to recover from ischemic injury, an assessment of respiratory activity may provide information related to graft viability. Methods NADH Fluorimetry can be used to monitor kidney cortex metabolism noninvasively. During perfusion with (an)-aerobic perfusate, NADH fluorescence images were recorded. We evaluated the NADH oxidation kinetics of 20 rat kidneys, which were divided over four experimental groups. For six minimally damaged kidneys and six kidneys that had been stored for one hour at 37°C, perfusion was followed by transplantation. We related the kinetic parameters of these kidneys with their post-transplantation function and histology. The transplant function was monitored by serum creatinine and urea levels. Results Storage of transplant kidneys for one hour at 37°C significantly reduced the post-transplantation function. Isolated perfusion of grafts, however, was not detrimental for renal function. The rate of NADH oxidation decreased with decreasing graft quality, and a good correlation between NADH oxidation kinetics and post-transplantation function was found. Conclusions A reduction of NADH oxidation rates as a consequence of warm ischemia supports the view that mitochondrial respiratory activity is impaired by ischemic injury. The correlation between NADH oxidation kinetics in perfused grafts and their post-transplantation function indicates that NADH Fluorimetry may be useful in predicting the viability of preserved grafts prior to transplantation.

Davide Cerioli - One of the best experts on this subject based on the ideXlab platform.

Eleftherios P Diamandis - One of the best experts on this subject based on the ideXlab platform.