Electron microscope study of leather I. effect of fixing and staining on the band pattern of collagen fibrils / Kohkichi Uehara in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXIX (Année 1984)

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXIX (Année 1984) . - p. 45-57 Titre : Electron microscope study of leather I. effect of fixing and staining on the band pattern of collagen fibrils Type de document : texte imprimé Auteurs : Kohkichi Uehara, Auteur ; Mieko Sutoh, Auteur ; Harukazu Toyoda, Auteur Année de publication : 1984 Article en page(s) : p. 45-57 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In order to observe the change of band pattern of collagen fibrils of hides and skins during the leather making process with transmission electron microscope, the effect of fixing and staining on the band pattern was studied first. Collagen fibrils obtained from rat tail tendon and SLS (Segment Long Spacing) - aggregates prepared from acid soluble tail tendon collagen were fixed with formaldehyde, glutaraldehyde, osmium tetroxide or chrome alum, and then positively or negatively stained with phophotungstic acid or uranyl acetate. In general, double positive staining gave far sharper and clearer images than single staining. When positively stained, collagen fibrils usually showed the period consisting of 11 or 12 bands, and contrast and sharpness of each band different according to the fixing method used. The sharpest and clearest images were obtained by fixing the fibrils with chrome alum. There was a great difference between the band pattern of SLS-aggregates fixed with chrome alum and those fixed with glutaraldehyde. These results indicate that the electron microscopic study of alteration of the band pattern is expected to provide important information on the mechanism of tanningg reactions. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9348 [article]

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Observation of skins, hides and leathers with scanning electron microscope, IV. Changes in pig skins during bating process / Kohkichi Uehara in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXII (Année 1987)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXII (Année 1987) . - p. 33-40 Titre : Observation of skins, hides and leathers with scanning electron microscope, IV. Changes in pig skins during bating process Type de document : texte imprimé Auteurs : Kohkichi Uehara, Auteur ; Harukazu Toyoda, Auteur ; Yasumasa Chonan, Auteur ; Hiroshi Okamura, Auteur Année de publication : 1987 Article en page(s) : p. 33-40 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The changes of the grain structure in pig skins during the bating process were observed with the scanning electron microscope. In addition, the amount of hydroxyproline released from pig skins during the bating process was determined and some physical properties of the bated skin pieces were measured. The humps of dermal papillae in the delimed skins were slight and the surface of papillae was flat. When the delimed skin was incubated with buffer solutions at pH 7.5 for 4 hr, the papillae swelled and the shapes of the surface were spherical, depresed or wrinkled. At a magnification of below 1,000 times, a new network structure was frequently observed in the surface of papillae of the skin pieces treated with pancreatin of Bacillus subtilis (B. sub) protease. This network was composed of the bundled grain fibrils. The grain fibrils in the delimed skin coalesced with each other and were surrounded with some amorphous substances. When treated with pancreatin, the grain fibrils were clearly exposed and separated from each other as shown by the micrographs only at high magnification. The amount of hydroxyproline released from the skin pieces during the enzyme treatment for 4 hr was less than 1%. The values of surface elongation and strain measured with a Tensometer decreased in the pieces treated with pancreatin or sub. protease. En ligne : https://drive.google.com/file/d/1hLnma872R1W2Xo1wBrRU-eaWWik1yXVB/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8962 [article]

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Solubilization of cattle and pig hair keratins by reduction with sodium thioglycolate or oxidation with performic acid / Kohkichi Uehara in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXI (Année 1986)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXI (Année 1986) . - p. 331-337 Titre : Solubilization of cattle and pig hair keratins by reduction with sodium thioglycolate or oxidation with performic acid Type de document : texte imprimé Auteurs : Kohkichi Uehara, Auteur ; Ayako Matsunaga, Auteur ; Katsuhiko Arai, Auteur ; Harukazu Toyoda, Auteur ; Yasumasa Chonan, Auteur Année de publication : 1986 Article en page(s) : p. 331-337 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : With the intention of utilizing solubilized keratins as a biomaterial, the solubilities of cattle and pig hair keratins were studied. Samples of hair were collected from steer hides and pig skins with razors and treated with sodium thioglycolate or performic acid. The effects of concentration of the reducing or oxidizing agent, incubation temperature and time on the solubility of hair keratins were examined. The results obtained were compared with those of human hair reported previously. About 60% of steer hair keratins and 50% of pig hair keratins were dissolved in 0.1M sodium thioglycolate at pH 11 and 35°C after 24 hr incubation. When oxidized with 90% formic acid - 3% hydrogen peroxide, the solubilities of steer hair and pig hair keratins were about 75% and 50% after 6 hr incubation, respectively. When the residues from hair oxidized with performic acid were incubated 0.2M sodium carbonate, additional keratins were dissolved. The total amount was about 95% of steer hair and 90% of pig hair after 24 hr incubation. En ligne : https://drive.google.com/file/d/1dwYqGgXqVaCjvEuPraCMvh3vW2YTM39Q/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9191 [article]

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