Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: K. Iwata x
  • All content x
Clear All Modify Search

Abstract  

The effect of the water vapor pressure on the thermal dehydration of manganese(II) formate dihydrate was studied by means of isothermal gravimetry under various water vapor pressure, ranging from 4.6 to 24.4 torr. The kinetics of dehydration was described by a two-dimensional phase-boundary model,R 2. The rate of dehydration decreased with increasing atmospheric water vapor pressure, but the Smith-Topley phenomenon was not observed for the present dehydration. The activation energy and the frequency factor for the dehydration were 110–170 kJ·mol−1 and 1010–1016 cm·s−1, respectively. These values increased with increasing water vapor pressure, and were much larger than those reported for the dehydration in vacuum.

Restricted access

Abstract  

The preparation of no-carrier-added48V(IV) and48V(V) from a natural titanium target irradiated by a proton beam has been developed. The48V recovered from the target by solvent extraction was purified as48V(V) with a cation exchange column and then converted to48V(IV) by reduction with ethanol. One hour irradiations at 10 A of 18 MeV protons gave approximately 2mCi (a radiochemical yield of 41%) of radiochemically pure and almost salt-free48V(IV) and48V(V) with high specific activities. They were shown to be suitable for biological tracer use.

Restricted access

The effects of the mycotoxin patulin on the thermodynamics and kinetics of the transition of bovine serum albumin (BSA) in aqueous solution were studied by Differential Scanning Calorimetry and Photoluminescence methods. Results show that in the presence of patulin, the free enthalpy change during the transition of BSA was decreased by an average of ∼ 46 kJ/mol, the free energy change was decreased by ∼ 4 kJ/mol, and the activation energy fell from ∼ 1546 to ∼ 840 kJ/mol. These results indicate that the bioactivity of patulin is based on the kinetic rather than on the thermodynamic properties of the transition. This is the first evidence of the direct interaction of patulin with the free thiol-containing BSA, a process which could contribute to the adverse cyto- and genotoxic effects induced by patulin.

Restricted access