In contrast to Gaussian or Woods-Saxon potential a two-term four parameter nuclear Hulthdn type inter- action is considered to describe the a-a, t-a He and t=3 H systems. By exploiting the phase function method, scatt...In contrast to Gaussian or Woods-Saxon potential a two-term four parameter nuclear Hulthdn type inter- action is considered to describe the a-a, t-a He and t=3 H systems. By exploiting the phase function method, scattering phase shifts are computed up to ELb -- 100 MeV for the a-a system and ELab = 15 MeV for a-3He and a-3H systems. The S-wave phase shift 5o for the system tends to 2n and 53/2_ for thea-3He system tends to n, in the limit of zero energy. Reasonable agreements in phase shifts with the standard data are obtained with this simple potential model except for the 5/2- states of a-3He and a-3H systems, With an additional energy-dependent correction factor to our potential, a good agreement with experimental data is obtained for 5/2- states. We have also compared our results with the convenient Born approximations.展开更多
We describe a simple one-pot thermal decomposition method for the production of a stable colloidal suspension of narrowly dispersed superparamagnetic Fe_(3)O_(4)-Ag core-shell nanostructures.These biocompatible nanost...We describe a simple one-pot thermal decomposition method for the production of a stable colloidal suspension of narrowly dispersed superparamagnetic Fe_(3)O_(4)-Ag core-shell nanostructures.These biocompatible nanostructures are highly toxic to microorganisms.Antimicrobial activity studies were carried out on both Gram negative(Escherichia coli and Proteus vulgaris)and Gram positive(Bacillus megaterium and Staphylococcus aureus)bacterial strains.Efforts have been made to understand the underlying molecular mechanism of such antibacterial actions.The effect of the core-shell nanostructures on Gram negative strains was found to be better than that observed for silver nanoparticles.The minimum inhibitory concentration(MIC)values of these nanostructures were found to be considerably lower than those of commercially available antibiotics.We attribute this enhanced antibacterial effect of the nanostructures to their stability as a colloid in the medium,which modulates the phosphotyrosine profile of the bacterial proteins and arrests bacterial growth.We also demonstrate that these core-shell nanostructures can be removed from the medium by means of an external magnetic field which provides a mechanism to prevent uncontrolled waste disposal of these potentially hazardous nanostructures.展开更多
Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested.Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L-1 and 50 mg L-1,indicating...Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested.Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L-1 and 50 mg L-1,indicating its tolerance to the metal.Accumulation rate of arsenic was always higher when exposed to As (V) at 50 mg L-1 than at 25 mg L-1.The study reveals Aspergillus flavus as a promising candidate for environmental bioremediation.Arsenic contents (mg g-1) in the fungus when exposed to 50 mg L-1 As (V) were measured as 11.1773,4.0983,and 8.0000 mg g-1 on day 3,6 and 9,respectively.The highest content was observed initially,i.e.on day 3,followed by a decline and a rise again.These results provide baseline information for further explorations regarding the exploitation of the fungus for arsenic removal.展开更多
文摘In contrast to Gaussian or Woods-Saxon potential a two-term four parameter nuclear Hulthdn type inter- action is considered to describe the a-a, t-a He and t=3 H systems. By exploiting the phase function method, scattering phase shifts are computed up to ELb -- 100 MeV for the a-a system and ELab = 15 MeV for a-3He and a-3H systems. The S-wave phase shift 5o for the system tends to 2n and 53/2_ for thea-3He system tends to n, in the limit of zero energy. Reasonable agreements in phase shifts with the standard data are obtained with this simple potential model except for the 5/2- states of a-3He and a-3H systems, With an additional energy-dependent correction factor to our potential, a good agreement with experimental data is obtained for 5/2- states. We have also compared our results with the convenient Born approximations.
基金the Department of Science and Technology(DST)New Delhi,India through the Ramanna Fellowship Scheme(No.SR/S2/RFCMP-01/2005)+2 种基金One of the Authors(A.K.V)is thankful to DST,New Delhi,for the FTPYS projectThe authors are also grateful to the Microbiology Department of Sir.P.P.Institute of Science,Bhavnagar University,Bhavnagar,for providing the culturesSpecial thanks are due to Dr.D.Srivastava,Scientist,CS&MCRI,Bhavnagar,for his help in TEM measurements.
文摘We describe a simple one-pot thermal decomposition method for the production of a stable colloidal suspension of narrowly dispersed superparamagnetic Fe_(3)O_(4)-Ag core-shell nanostructures.These biocompatible nanostructures are highly toxic to microorganisms.Antimicrobial activity studies were carried out on both Gram negative(Escherichia coli and Proteus vulgaris)and Gram positive(Bacillus megaterium and Staphylococcus aureus)bacterial strains.Efforts have been made to understand the underlying molecular mechanism of such antibacterial actions.The effect of the core-shell nanostructures on Gram negative strains was found to be better than that observed for silver nanoparticles.The minimum inhibitory concentration(MIC)values of these nanostructures were found to be considerably lower than those of commercially available antibiotics.We attribute this enhanced antibacterial effect of the nanostructures to their stability as a colloid in the medium,which modulates the phosphotyrosine profile of the bacterial proteins and arrests bacterial growth.We also demonstrate that these core-shell nanostructures can be removed from the medium by means of an external magnetic field which provides a mechanism to prevent uncontrolled waste disposal of these potentially hazardous nanostructures.
基金due to the Department of Science and Technology,Government of India,for financial support sanctioned under SERC Fast Track Proposals for Young Scientists Scheme (No. SR/FT/L-99/2006) to AKV
文摘Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested.Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L-1 and 50 mg L-1,indicating its tolerance to the metal.Accumulation rate of arsenic was always higher when exposed to As (V) at 50 mg L-1 than at 25 mg L-1.The study reveals Aspergillus flavus as a promising candidate for environmental bioremediation.Arsenic contents (mg g-1) in the fungus when exposed to 50 mg L-1 As (V) were measured as 11.1773,4.0983,and 8.0000 mg g-1 on day 3,6 and 9,respectively.The highest content was observed initially,i.e.on day 3,followed by a decline and a rise again.These results provide baseline information for further explorations regarding the exploitation of the fungus for arsenic removal.
