Collagen structure changes during chrome tanning in propylene carbonate / Yi Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 7 p. Titre : Collagen structure changes during chrome tanning in propylene carbonate Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Jenna Kate Buchanan, Auteur ; Geoff Holmes, Auteur ; Bradley William Mansel, Auteur ; Sujay Prabakar, Auteur Année de publication : 2019 Article en page(s) : 7 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Carbonate de propylène Collagène -- Structure Cuirs et peaux Diffusion de la lumière aux petits angles Tannage au chrome Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Green solvents, such as propylene carbonate (PC), can be used in leather processing to improve the efficiency of chrome tanning and reduce wastewater. Here we report a combined small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) study on PC and its efficacy as a carrier medium during chrome tanning. SAXS analysis on the collagen structure of chrome tanned leather using PC, compared to conventionally tanned leather using water, showed an increase in Cr uptake in addition to the more uniform penetration of Cr through the leather cross-section. The increased binding of Cr to the collagen matrix drives the decreased hydration environment of the collagen triple helix. Furthermore, DSC studies show a uniform hydrothermal stability for the PC samples due to the more even distribution of Cr through the collagen matrix. Understanding the mechanisms by which chrome tanning occurs in non-aqueous solvents can guide us towards a more sustainable future for the leather industry. Note de contenu : - EXPERIMENTAL : Materials - Leather sample preparation - Small-angle X-ray scattering (SAXS) measurements - Differential scanning calorimetry (DSC) measurements - Percentage uptake of chromium - RESULTS AND DISCUSSION : Chromium uptake from AAS studies - SAXS peak changes with tanning - D-period changes through the leather cross-section - Changes in R6/5 - DSC studies DOI : https://doi.org/10.1186/s42825-019-0011-y En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0011-y.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36953 [article]

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Decolorisation and mineralisation of CI Reactive Black 8 by the Fenton and ultrasound/Fenton methods / Hui Zhang in COLORATION TECHNOLOGY, Vol. 123, N° 2 (2007)  

[article]  inCOLORATION TECHNOLOGY > Vol. 123, N° 2 (2007) . - p. 101-105 Titre : Decolorisation and mineralisation of CI Reactive Black 8 by the Fenton and ultrasound/Fenton methods Type de document : texte imprimé Auteurs : Hui Zhang, Auteur ; Daobin Zhang, Auteur ; Yi Zhang, Auteur Année de publication : 2007 Article en page(s) : p. 101-105 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.3 Teinture et impression des tissus Résumé : The effects of pH, ferrous ion and hydrogen peroxide dosage on the decolorisation and mineralisation of CI Reactive Black 8 by the Fenton process with/without ultrasonic irradiation were investigated. It was verified that the presence of ultrasonic irradiation did not enhance the decolorisation of CI Reactive Black 8 significantly by Fenton's reagents, but it enhanced the chemical oxygen demand removal efficiency. The enhancement was more pronounced for lower (<0.89 mm) or higher (>1.78 mm) ferrous ion dosage. The optimal pH for chemical oxygen demand removal was 3.0. Chemical oxygen demand removal efficiency increased with the increasing H2O2 dosage and reached the highest level at 5.88 mm, but further increase in H2O2 dosage would not increase removal efficiency significantly. Note de contenu : - Effect of pH on colour and COD removal - Effect of hydrogen peroxide dosage on colour and COD removal - Effect of ferrous ion dosage on colour and COD removal - UV-vis spectra changes in Fenton and US/Fenton system DOI : 10.1111/j.1478-4408.2007.00069.x En ligne : http://onlinelibrary.wiley.com/doi/10.1111/j.1478-4408.2007.00069.x/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3551 [article]

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Effect of coloration with various metal oxides on zirconia / Jianfeng Chen in COLORATION TECHNOLOGY, Vol. 131, N° 1 (02/2015)  

[article]  inCOLORATION TECHNOLOGY > Vol. 131, N° 1 (02/2015) . - p. 27-31 Titre : Effect of coloration with various metal oxides on zirconia Type de document : texte imprimé Auteurs : Jianfeng Chen, Auteur ; Yi Zhang, Auteur ; Shuwen Dong, Auteur ; Lisheng Zhao, Auteur ; Bin Gu, Auteur ; Ningfang Liao, Auteur ; Ning Wen, Auteur Année de publication : 2015 Article en page(s) : p. 27-31 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Céramique industrielle Colorimétrie Oxyde de bismuth Oxyde de cérium Oxyde de fer Pigments -- Synthèse Pigments inorganiques vision des couleurs Zircone Le dioxyde de zirconium ou oxyde de zirconium(IV) couramment appelée zircone est un composé inorganique du zirconium de formule ZrO2. Ce matériau est une céramique technique d'aspect opaque. Appelé CZ (Cubic Zirconia) lorsque transparent, il est utilisé pour imiter le diamant. Il ne faut pas le confondre avec le zircon (ZrSiO4). Sous sa forme tétragonale, l'oxyde de zirconium est un matériau a vocation mécanique, cette évolution cristallographique lui confère une dureté très élevée (1200Hv) ainsi qu'une bonne résistance aux sollicitations mécaniques (700Mpa en traction et 2000Mpa en compression). Une fois polie, la zircone tétragonale peut atteindre un Ra de 0,02, ce qui permet de l'utiliser pour des pièces de frottement. Index. décimale : 667.3 Teinture et impression des tissus Résumé : The aim of this study was to evaluate the coloration of zirconia ceramic by adding three kinds of metal oxide. This was done with different concentrations of Fe2O3, CeO2, and Bi2O3 in tetragonal zirconia polycrystals stabilised with 3Y-TZP powder compacted at 200 MPa using cold isostatic pressure and full sintering. X-ray diffraction analysis was used to examine the structure of the shaded 3Y-TZP. The chromaticity of sintered bodies was measured on a spectrophotometer. The coloration of zirconia by the three kinds of metal oxide was determined. With the addition of CeO2, the lightness of the zirconia was about 84–87, a* decreased slightly, and the colour shifted to a more yellow-green hue. With an increasing content of Fe2O3, the chroma of the ceramic became more intense, the lightness decreased, and the colour changed to a red-yellow hue. With an increasing concentration of Bi2O3, the colour of the materials shifted to a light saffron yellow. X-ray diffraction spectra revealed only tetragonal phase. Results show that zirconia ceramic can be colourised using Fe2O3, CeO2, and Bi2O3. Note de contenu : - EXPERIMENTAL : Specimen preparation - Colour measurement - Characterisation of the specimens - Statistical analysis - RESULTS AND DISCUSSION : X-ray diffraction analysis - Scanning electron microscopy observation - Colour properties DOI : 10.1111/cote.12118 En ligne : https://onlinelibrary.wiley.com/doi/epdf/10.1111/cote.12118 Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22979 [article]

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Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS / Yi Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 9 p. Titre : Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Rafea Naffa, Auteur ; Christopher J. Garvey, Auteur ; Catherine Maidment, Auteur ; Sujay Prabakar, Auteur Année de publication : 2019 Article en page(s) : 9 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Chromatographie en phase liquide Collagène -- Structure Cuirs et peaux Réticulation (polymérisation) Spectrométrie de masse Traceurs radioactifs Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Collagen structure in biological tissues imparts its intrinsic physical properties by the formation of several covalent crosslinks. For the first time, two major crosslinks in the skin dihydroxylysinonorleucine (HLNL) and histidinohydroxymerodesmosine (HHMD), were isotopically labelled and then analysed by liquid-chromatography high-resolution accurate-mass mass spectrometry (LC-HRMS) and small-angle neutron scattering (SANS). The isotopic labelling followed by LC-HRMS confirmed the presence of one imino group in both HLNL and HHMD, making them more susceptible to degrade at low pH. The structural changes in collagen due to extreme changes in the pH and chrome tanning were highlighted by the SANS contrast variation between isotopic labelled and unlabelled crosslinks. This provided a better understanding of the interaction of natural crosslinks with the chromium sulphate in collagen suggesting that the development of a benign crosslinking method can help retain the intrinsic physical properties of the leather. This analytical method can also be applied to study artificial crosslinking in other collagenous tissues for biomedical applications. Note de contenu : - EXPERIMENTAL METHODS : Materials and methods - RESULTS AND DISCUSSION : Characterization of natural crosslinks in skin collagen : isotopic labelling using NaBD4 and mechanism of HHMD formation - Quantification of natural crosslinks in skin collagen : relationship with pH and crosslinking conditions - Structural analysis of skin collagen : interplay between natural and artificial crosslinks - Table 1 : Collagen D-periodicity at different processing stages in control, reduced and labelled skin samples. The D-period decreased for all samples starting from raw to the pickled stage, then increased at the crosslinked stage DOI : https://doi.org/10.1186/s42825-019-0012-x En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0012-x.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36955 [article]

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Studies on collagen structure using X-ray scattering on a closed-loop leather process / Yi Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 10 (10/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 10 (10/2020) . - p. 373-379 Titre : Studies on collagen structure using X-ray scattering on a closed-loop leather process Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Jenna Buchanan, Auteur ; Jiasheng Su, Auteur ; Zhuangdou Zhang, Auteur ; Geoff Holmes, Auteur ; Sujay Prabakar, Auteur Année de publication : 2020 Article en page(s) : p. 373-379 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène -- Analyse Cuirs et peaux -- Déchets -- Recyclage Diffractométrie de rayons X Diffusion aux petits angles Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Waste management in leather processing is crucial in limiting the excess use of hazardous materials that lead to environmental pollution and health concerns. A closed-loop approach was developed to recycle the spent solutions from leather processing to reduce waste in the effluent. The structural changes of collagen that accompany such processing are yet to be studied and is crucial in understanding the closed-loop process and its subsequent leather properties. In this study, we analysed the collagen structure at different processing stages across the closed-loop approach using synchrotron small-angle X-ray scattering. An increased filling effect in the collagen matrix was observed and attributed to the residual organic component and chromium species in recycled spent solutions. A high uptake of chromium was also observed from the increased scattering intensity from leathers treated with recycled chrome solution, indicating its efficient use. Additionally, the changes in scattering intensity from keratin and lipids indicated an effective unhairing process. Such findings on collagen structure changes will support the development of more environmentally and economically sustainable processing methods to benefit the leather industry. Note de contenu : - Sample preparation - Small-angle X-ray scattering (SAXS) DOI : https://doi.org/10.34314/jalca.v115i10.4175 En ligne : https://drive.google.com/file/d/1B-AuPs8xRaBRWnOHDBZ7bKgDVRzJMpeE/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34612 [article]

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