In order to determine the deuterium diffusion coefficient in metals, we have developed a new technique, ion driven permeation in which the implantation of energetic ions is utilized instead of gaseous charging or electrochemical charging for deuterium permeation.The time sequence of deuterium permeation rate caused by the ion implantation is generally similar to those of the other techniques. The steady state permeation rate and the diffusion coefficient, however, tend to decrease with increasing duration of implantation (or with increasing implanted fluence) because of modifications of the surface or subsurface region, or both, by the bombardment. Therefore, the diffusion coefficients determined from the initial rise of the permeation rate for a fully annealed specimen are reproducible and reliable.The diffusion coefficient thus determined are for deuterium in Cu and Ni at 500-1000 K, respectively. Both are in agreement with the literature values. Applying this technique to Al and Mo, the deuterium diffusion coefficients are determined to be Since energetic deuterium is implanted directly into the bulk, the experimental value for Al seems not to be influenced by the surface oxide, whereas that for Mo is possibly influenced by defects produced by the bombardment.
The isolate, Pesudoalteromonas sp. TBT1, could grow to overcome the toxicity of tributyltin chloride (TBTCl) up to 30 microM in the absence of Cl(-) in the medium until the cells reached an exponential phase of growth. The viability, however, was reduced after the cells reached a stationary phase. The degradation products, such as dibutyltin (DBT) and monobutyltin (MBT), were not detected in the growth medium, indicating that the isolate has no ability to degrade TBT into less toxic DBT and MBT. Up to about 10(7.5) TBT molecules were adsorbed by a single cell. The observation of morphological changes with an electron microscope showed that the cell surface became wrinkled after exposure to the lethal concentration of 10 mM TBTCl. These results indicate that the resistance of the isolate toward the toxicity of TBTCl is not related to the unique cell surface, which seems to play an important role in preventing the diffusion of TBTCl into the cytoplasm.
Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship's ballast water. The isolate (10 9.3 ± 0.2 colony-forming units mL -1 ) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 10 8.2 . The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 10 6.8 TBT molecules is adsorbed by a single cell.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.