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K Miyabe

Publications and source records attributed to K Miyabe.

22 records · Page 2Linked to original sources
PubMedDate not supplied

A study of mass transfer kinetics in an enantiomeric separation system using a polymeric imprinted stationary phase.

Chromatographic data pertaining to the enantioseparation of L- and D-phenylalanine anilide (PA) on a polymeric stationary phase imprinted with L-PA were studied from the viewpoints of phase equilibrium, mass transfer kinetics, and the thermodynamic properties of this enantiomeric separation system. The concentration dependence of the lumped mass transfer rate coefficient (k(m,L)) previously published was analyzed to obtain new information concerning the mass transfer characteristics in this chiral separation system. It was shown that intraparticle diffusion contributed much more to k(m,L) than adsorption/desorption. The positive concentration dependence of k(m,L) seemed to be interpreted by considering that of the surface diffusion coefficient, itself explained by the heterogeneous surface model. The characteristic features of the phase equilibrium, the mass transfer kinetics, and the thermodynamics of the enantiomeric separation system probably result from the adsorption energy distribution on the surface of the imprinted phase having an exponential decay.

Adsorption↗
PubMedDate not supplied

Kinetic study of the concentration dependence of the mass transfer rate coefficient in anion-exchange chromatography of bovine serum albumin.

The experimental results of a previous study of the mass transfer kinetics of bovine serum albumin (BSA) in ion-exchange chromatography under nonlinear conditions are reevaluated. The analysis of the concentration dependence of the lumped mass-transfer rate coefficient (k(m,L)) provides information on the kinetics of axial dispersion, fluid-to-particle mass transfer, intraparticle mass transfer, and adsorption/desorption. The new analysis shows that the contribution of intraparticle mass transfer is the dominant one. Similar to k(m,L), the surface diffusivity (D(s)) of BSA increases with increasing concentration. The linear concentration dependence of k(m,L) seems to originate in a similar dependence of D(s). The use of an heterogeneous-surface model for the anion-exchange resin provides an explanation of the positive concentration dependence of D(s). This work illustrates how frontal analysis data can be used for a detailed investigation of the kinetics of mass transfer between the phases of a chromatographic column, in addition to its conventional use in the determination of the thermodynamic characteristics of the phase equilibrium.

Adsorption↗
PubMedDate not supplied

Malignant plasmacytoid myoepithelioma of the palate: histological observations compared to benign predominant plasmacytoid myoepithelial cells in pleomorphic adenoma of the palate.

Predominant benign plasmacytoid myoepithelial cells in pleomorphic adenoma and malignant plasmacytoid myoepithelioma cells were investigated morphologically. The cells of both tumors were plasmacytoid in appearance and sheet-like. Immunohistochemically, they were positive for keratin, vimentin, and S-100 protein, and negative for alpha-smooth muscle actin. In the malignant cells, large nuclei with irregular nuclear membranes and distinct nucleoi and occasional intranuclear inclusions and nuclear grooves were seen. Ultrastructural findings showed that the benign cells were richer in intermediate filaments and had fewer mitochondria. The intranuclear inclusions and nuclear grooves of the malignant cells were caused by invagination of the irregular nuclear membranes. Taken in their entirety, the above light microscopical nuclear findings may be useful as an adjunct for distinguishing malignant from benign plasmacytoid neoplastic myoepithelial cells of the salivary gland.

Adenoma, Pleomorphic↗