We have succeeded in creating Menger sponge-like fractal body, i.e., porous-silica samples with Menger sponge-like fractal geometries, by a novel template method utilizing template particles of alkylketene dimer (AKD) and a sol-gel synthesis of tetramethyl orthosilicate (TMOS). We report here the first experimental results on characterization and structural investigations of the fractal porous-silica samples prepared with various conditions such as calcination temperature and packing condition of the template particles. In order to characterize the fractal porous-silica samples, pore volume distribution, porosity and specific surface area were measured over an extremely wide scale from 1 nm to 100 m by means of mercury porosimetry, 1 H NMR cryoporometry, and nitrogen gas adsorption experiments together with direct evaluations of cross-sectional fractal dimension D cs , size limits of D cs . We have found that the pore volume distribution and specific surface area of the fractal porous-silica samples can be discussed in terms of different fractal porous structures at different scale regions.
The biological functions of chondroitin sulfate (CS) are executed by the interaction of specific oligosaccharide sequences in the polysaccharide chain with effective proteins. Thus, CS oligosaccharides are expected to have pharmacological applications. Furthermore, the demand for CS in health food supplements and medication is growing. However, the absorbency of CS polysaccharides in the digestive system is very low. Since the activity of orally administered CS is expected to increase by depolymerization, industrial production of CS oligosaccharides is required. In this study, hydrolysis with subcritical and super-critical water was applied to the depolymerization of CS for the first time, and hydrolytic conditions for oligosaccharide production were examined. CS oligosaccharides principally containing an N-acetyl-Dgalactosamine residue at their reducing ends were successfully obtained. No significant desulfation was found in CS oligosaccharides prepared under optimized conditions. The production of CS oligosaccharides by this method will have a strong influence on the CS-related materials market.
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