Diffusion abnormality in the posterior cingulum and hippocampal volume: correlation with disease progression in Alzheimer's disease

The purpose of this study was to determine correlations among disease progression, diffusion abnormalities in the posterior cingulum and hippocampal volume in patients with Alzheimer's disease (AD). We studied 25 AD patients by neuropsychological testing, including the Mini-Mental State Examination (MMSE), and by magnetic resonance imaging, including diffusion tensor imaging (DTI) and high-resolution three-dimensional T1-weighted imaging. The MMSE score was used as an indicator of disease progression. Diffusion tensor tractography of the posterior cingulum was generated from the DTI; mean diffusivity (MD) and fractional anisotropy (FA) were measured in co-registered voxels along the posterior cingulum. Hippocampal volume was measured using automated voxel-based morphometry. The relationships among MMSE score, hippocampal volume and MD and FA of the posterior cingulum were evaluated by bivariate correlation analysis. MD in the posterior cingulum correlated significantly with the MMSE score. No significant correlation was seen between FA and MMSE score and between hippocampal volume and MMSE score, FA or MD. Our results suggest that MD in the posterior cingulum is a more sensitive indicator of progression of AD than FA of the posterior cingulum and hippocampal volume.     

Solid polymer electrolytes based on poly(lithium carboxylate) salts

The ionic conductivity, lithium ion transference number, electrochemical stability, and thermal property of solid polymer electrolytes composed of poly(ethylene oxide) (PEO) and poly(lithium carboxylate)s, (poly(lithium acrylate) (Poly(Li-A)) or poly(lithium fumarate) (Poly(Li-F)), with and without BF₃·OEt₂ were investigated. The ionic conductivities of all solid polymer electrolytes were enhanced by one to two orders of magnitude with addition of BF₃·OEt₂ because the dissociation of lithium ion and carboxylate anion was promoted by the complexation with BF₃. The lithium ion transference number in the solid polymer electrolytes based on poly(lithium carboxylate)s showed relatively high values of 0.41–0.70, due to the suppression of the transport of counter anion by the use of a polymeric anion. The solid polymer electrolytes with addition of BF₃·OEt₂ showed good electrochemical stability.     

Polymerization of perhydro-1,5-diazocine-2,6-dione

Perhydro-1,5-diazocine-2,6-dione polymerized in solid state in the presence of water in vapor phase and produced poly-β-alanine almost quantitative yield. Further, this monomer was found to polymerize rapidly on heating above its melting temperature without water. The results of x-ray diffraction measurement and thermal analysis suggest that this solid-state polymerization is like partial melt polycondensation.     

First synthesis of a series of core-modified tetrabenzoporphyrins

Successful synthesis of a series of highly conjugated porphyrin analogues, including thia-, dithia- and oxathia-tetrabenzoporphyrins, and their optical properties are reported.     

Polymerization of isocyanates. III. Chemical behavior and structure of polyisocyanates

The chemical behavior of polyisocyanates was investigated. Dissociation of the polymer to the monomer was observed directly by infrared spectra. Aminolysis of the polymer gave cyclic trimer and asymmetric urea as reaction products, and the formation of the latter was ascribed to the reaction of amine with the monomer dissociated from the polymer. It was concluded that polyisocyanates are composed of disubstituted amide structure only.