Studies on syntheses and permeabilities of special polymer membranes, 36. Permeabilities of alcohols through poly(γ-alkyl l-glutamate) membranes

To reveal the permeation mechanism of liquids through polypeptide membranes, the permeation of n-alcohols through poly(γ-alkyl L-glutamate) membranes such as the polymers of methyl, ethyl, and benzyl glutamates was investigated by changing the operating temperature. It was found that there was a significant interaction between the ester groups of the side chain of poly(γ-alkyl L-glutamate) and the alcohol molecule. This interaction affected significantly the permeation rates of alcohols and the separation characteristics of alcohol mixtures.     

Radiation-induced sol-gel transition of protein: Effects of radiation on diffraction property

Solid gelatin was irradiated with ⁶⁰Co gamma rays, and the effects of radiation on the diffraction property of the protein molecule were studied by measuring the X-ray diffraction intensity at different radiation doses and elapsed times after irradiation. The effects of radiation on the ordered conformation of the protein molecule were discussed. © 1993 John Wiley & Sons, Inc.     

Use of the Reflection of Near‐Infrared Light for the Nondestructive Examination of Blood Flow and Other Applications

Abstract

Reflection of near‐infrared light is measured by commercial equipment. We found that samples in motion and at rest show differences in the intensity of reflection of a laser beam. This may suggest the possibility of its use to detect organ necrosis in vivo. In addition, we find the possibility of the use of this reflection of the near‐infrared light for the non‐destructive inspection of internal changes in perishables, e.g., their degree of ripeness.     

Lantibiotics Produced by Oral Inhabitants as a Trigger for Dysbiosis of Human Intestinal Microbiota

Lantibiotics are a type of bacteriocin produced by Gram-positive bacteria and have a wide spectrum of Gram-positive antimicrobial activity. In this study, we determined that Mutacin I/III and Smb (a dipeptide lantibiotic), which are mainly produced by the widespread cariogenic bacterium Streptococcus mutans, have strong antimicrobial activities against many of the Gram-positive bacteria which constitute the intestinal microbiota. These lantibiotics also demonstrate resistance to acid and temperature. Based on these features, we predicted that lantibiotics may be able to persist into the intestinal tract maintaining a strong antimicrobial activity, affecting the intestinal microbiota. Saliva and fecal samples from 69 subjects were collected to test this hypothesis and the presence of lantibiotics and the composition of the intestinal microbiota were examined. We demonstrate that subjects possessing lantibiotic-producing bacteria in their oral cavity exhibited a tendency of decreased species richness and have significantly reduced abundance of the phylum Firmicutes in their intestinal microbiota. Similar results were obtained in the fecal microbiota of mice fed with S. mutans culture supernatant containing the lantibiotic bacteriocin Mutacin I. These results showed that lantibiotic bacteriocins produced in the oral cavity perturb the intestinal microbiota and suggest that oral bacteria may be one of the causative factors of intestinal microbiota dysbiosis.     

Radiation-induced sol–gel transition of protein: Effects of metal ions on flow and melting properties

Solid protein was irradiated with ⁶⁰Co gamma rays, and the effects of metal ions (Cu²⁺ and Fe²⁺) on irradiated protein molecules were studied by measuring the viscosity of the protein hydrosol and the melting point of the protein hydrogel at different radiation doses and different concentrations of the metal ions. The effects of metal ions on the flow and thermal properties of irradiated protein molecules were discussed.     

Radiation chemical studies of protein reactions: Radiation dose and viscosity change

When protein was irradiated by gamma rays from a cobalt 60 source, an activated state was caused. An empirical equation for the viscosity change was obtained, and the phenomena were explained on the basis of the molecular mechanism. The general equation for the viscosity change is given by η_red = (b + a log R)(1 ? e^?kt), where η_red is the reduced viscosity of the solution, R is the gamma radiation dose, and t is time.     

Studies on syntheses and permeabilities of special polymer membranes. 62. Active transport of alkali metal ions through poly(vinyl alcohol) membranes crosslinked with glutaraldehyde

The transport of alkali metal ion through poly(vinyl alcohol) crosslinked with glutaraldehyde without dissociating groups in a diaphragm cell, at one side being an alkaline and at the other an acidic solution, was investigated under various conditions. The active transport fraction of alkali metal ions from the alkaline side to the acidic side was significantly influenced by the degree of crosslinking of the membrane, size of anion species, initial pH on the acidic side, and the electric potential difference across the membrane.     

Environmental stress relaxation studies of polymers

Polyethylene films were irradiated by ⁶⁰Co gamma-rays, and the effect of ionizing radiation on polyethylene — ketone system was studied by the method of stress relaxation. An empirical equation for the rate constant of penetrant-enhanced relaxation in the polyethylene — ketone system was obtained.     

A modified capillary dilatometer for polymerization

A relatively simple and inexpensive instrument giving good accuracy and easy operation has been developed for the measurement of volume change in monomer polymerizations. The instrument is based on a previously described capillary dilatometer intended for automatic operation.