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Study on interaction mechanism between neutral salts and collagen by combining experiments with molecular dynamics simulation / Min Gu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 7 (07/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 7 (07/2023) . - p. 271-281 Titre : Study on interaction mechanism between neutral salts and collagen by combining experiments with molecular dynamics simulation Type de document : texte imprimé Auteurs : Min Gu, Auteur ; Xiaoxia Zhang, Auteur ; Yuanzhi Zhang, Auteur ; Songcheng Xu, Auteur ; Guoying Li, Auteur Année de publication : 2023 Article en page(s) : p. 271-281 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chlorure de calcium Chlorure de sodium Le chlorure de sodium est un composé chimique de formule NaCl. On l'appelle plus communément sel de table ou de cuisine, ou tout simplement sel dans le langage courant. C'est le principal produit dissous dans l'eau de mer ; on l'appelle alors sel marin. On l'obtient : dans des marais salants par évaporation de l'eau de mer, dans des mines, par extraction du sel gemme (halite) ou en le synthétisant lors de réactions à hautes températures entre du dichlore (Cl2) et du sodium métallique (Na). Le chlorure de sodium est utilisé dans l'industrie chimique pour produire du chlore, de la soude caustique et de l’hydrogène. Collagène Collagène -- Analyse Dynamique moléculaire Lumière -- Diffusion Microscopie à force atomique Potentiel zeta Simulation, Méthode de Solutions (chimie) Spectroscopie de fluorescence Sulfate de sodium Le sulfate de sodium est un composé chimique courant formé d'un ion sulfate et de deux ions sodium. Lorsqu'il est anhydre, il prend l'apparence d'un solide cristallin blanc de formule chimique Na2SO4. La forme déca-hydratée, Na2SO4·10H2O, est connue sous le nom de sel de Glauber ou mirabilite. Parmi un grand nombre d'usages différents, les principales utilisations du sulfate de sodium concernent la fabrication des détergents et dans le procédé de Kraft de traitement de la pâte à papier. La moitié environ de la production mondiale provient de l'extraction de la forme naturelle décahydratée, et l'autre moitié de productions secondaires dans des procédés de l'industrie chimique. Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The effect of salt on the collagen of hide/skin is of great significance in leather-making. However, the interaction between neutral salts and collagen has not been clear, since the microscopic interaction is hard to be observed directly from the macro level of hide/skin collagen. In this study, the collagen solutions in the typical neutral salts (NaCl, CaCl2, and Na2SO4) systems were used to explore the interaction mechanism between neutral salts and collagen via combining experiments with molecular dynamics (MD) simulation. The results of fluorescence measurements of pyrene, dynamic light scattering, atomic force microscopy, and isoelectric point suggested that the variation of the interaction between different neutral salts and collagen was accompanied with the changes in physicochemical properties of collagen. MD simulation further revealed more detailed information on the interaction mechanism between neutral salts and collagen at the molecular level. The computational results of non-bond energy of the collagen-salt model boxes indicated that the electrostatic interactions of different salts with collagen molecules had the order of CaCl2> Na2SO4> NaCl. The analyses of the visualized conformation and the radial distribution functions showed that CaCl2 with Ca2+ as contributing ion tended to form intramolecular salt bridges with collagen, while Na2SO4 with SO42-as contributing ion more likely formed salt bridges between collagen molecules in the shape of agglomerates. In contrast, NaCl with Cl-as contributing ion was scattered around the collagen models, and its effect on collagen was much smaller. The study elaborated the interaction mechanism of typical neutral salts and collagen to be helpful for further understanding and improving the use of neutral salts in many steps involved in leather production. Note de contenu : - MATERIALS AND METHODS : Materials - Preparation of collagen solutions with salts - Measurments of pyrene fluorescence spectra - Measurements of dynamic light scattering - Atomic force microscope measurements - Measurements of zeta potential - Construction of collagen model and simulation boxes - Molecular dynamics simulation - RESULTS AND DISCUSSION : Pyrene fluorescence spectra analysis - Dynamic Light Scattering (DLS) analysis - Atomic Force macroscopic (AFM) images - Zeta potential analysis - Non-bond energy analysis in different salt systems - Interactions between collagen and salts by conformation analysis - Radial distribution function analysis - Table 1 : The I1/I3 Ratio values of pyrene in 0.5 mg/mL collagen solutions containing 0–200 mM salts (NaCl, CaCl2 and Na2SO4) and the CAC values of collagen in 0 mM and 80 mM salts - Table 2 : Non-bond energies (kcal/mol) of collagen model in [pure col] system and different salt systems DOI : https://doi.org/10.34314/jalca.v118i7.7855 En ligne : https://drive.google.com/file/d/1F9oD_1lM1fCPfmu-6WzHTCWXnEWjEzmt/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39661 [article]

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Region wise surface level defect detection and ranking of crust leather images based on image processing techniques / S. Nithiyanantha Vasagam in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 7 (07/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 7 (07/2023) . - p. 282-292 Titre : Region wise surface level defect detection and ranking of crust leather images based on image processing techniques Type de document : texte imprimé Auteurs : S. Nithiyanantha Vasagam, Auteur ; M. Sornam, Auteur Année de publication : 2023 Article en page(s) : p. 282-292 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse d'image L'analyse d'image est la reconnaissance des éléments contenus dans l'image. Il ne faut pas confondre analyse (décomposition en éléments) et traitement (action sur les composantes) de l'image. Croûte (cuir) On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés. Cuirs et peaux -- Défauts Détection de défauts (Ingénierie) Surfaces -- défauts Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Sorting and aligning of crust leather for grading on position wise defect distribution is one of the methods adopted in the tanning industry. This method is generally carried out manually by a veteran on official sampling position and their input is critical because it is directly linked to sales of the crust leather. The opinion of the experts is believed to be stable and consumes a good amount of time too. Hence, in the current research a robust defect detection method and ranking of crust leather images based on image processing techniques is proposed to give a stable solution in a short span of time. A custom-made dataset of crust leather images consisting of 5640 images were used in this study. The pixel intensity has been extracted on demarcated position of various regions including neck, belly left, belly right, center and butt instead of official sampling position through horizontal and vertical mapping of coordinates with a new method Grading Score on Image Position wise (GSIP) on the actual images. The image processing techniques using Canny Edge Detection and filters such as Laplacian, Median, Prewitt, Roberts, Sobel and Scharr were implemented to get the pixel intensity grouped and classified based on parameters within acceptable range using a Naïve Bayes Classifier. The classifier confirms that the accuracy of Set I - Actual Images and Set II - Defects with implementation of canny edge detection over other image processing techniques at 99.50%. Therefore, the current research confirms that the proposed GSIP method would give an additional tool to inspectors while ranking the crust leather based on region wise surface level defect detection of crust leather images based on image processing techniques. Note de contenu : - Dataset of crust leather images - Regions wise horizontal and vertical mapping - Feature extraction - Generation of ranking matrix - Classification with naive bayes - Table 1 : Summary of Authors, Techniques and Area - Table 1 : Sample 6×6 Matrix representation of pixel points where i is row, j is column and n represent the size = 6 - Table 2 : Representation of three region mapping of pixel point as Row Size (RS) = n/3 - Table 3 : Cutting area and corresponding Grading - Table 4 : Intermittent Leather grading based on area of usefulness based on demerit count - Table 5 : Ranking based on Pixel intensity value associated with the co-ordinates of horizontal (Row i) and vertical (Column j) - Table 6 : Coordinates for an image of 250 × 250 - Table 7 : Demarcated position of various regions within the hide for surface defect detection - Table 8 : Ranking of Dataset I and II - Table 9 : Naïve Bayes Classifier Comparison of various image files DOI : https://doi.org/10.34314/jalca.v118i7.7856 En ligne : https://drive.google.com/file/d/1KlGnwGbGA8ZA6a6wO5y74ab-LV-tcsz4/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39662 [article]

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Isolation and identification of moderately halophilic bacteria from soak liquor samples collected of leather tanneries / Pinar Caglayan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 7 (07/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 7 (07/2023) . - p. 293-300 Titre : Isolation and identification of moderately halophilic bacteria from soak liquor samples collected of leather tanneries Type de document : texte imprimé Auteurs : Pinar Caglayan, Auteur Année de publication : 2023 Article en page(s) : p. 293-300 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bactéries -- Identification Bactéries -- Isolement Bactéries halophiles Bains de trempe -- Analyse Cuirs et peaux Cuirs et peaux -- Détérioration Cuirs et peaux de moutons Détérioration enzymatique Enzymes microbiennes Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Isolation and identification of protease and lipase producing moderately halophilic bacteria from soak liquor samples and studying their adverse effects to the sheepskin using scanning electron microscopy may provide critical data on decomposition of raw hide/skin materials during soaking process. Moreover, enzyme-production properties of the moderately halophilic isolates (such as catalase, oxidase, lipase, protease, urease, caseinase, amylase, cellulase, pullulanase, xylanase) were determined. The effects of different NaCl concentrations, pH and temperature values on the growth of moderately halophilic bacterial isolates were tested. In the present study, four moderately halophilic bacterial isolates were isolated and selected for further experiments. The isolated species designated as SLMHB5, SLMHB10, SLMHB12, SLMHB13 were similar to Vibrio alginolyticus, Terribacillus halophilus, Vibrio alginolyticus, and Vibrio parahaemolyticus species, respectively. Scanning electron micrographs of sheepskin samples demonstrated that enzymatic activities of moderately halophilic bacteria isolated from soak liquor samples which decomposed the skin structure. After 35-days storage period, the sheepskin sample showed bad odor, sticky appearance and hair slip. Hence, it is recommended to control these microorganisms during the soaking process with an effective antimicrobial agent. Note de contenu : - Soak liquor samples - Isolation of moderately halophilic bacteria from soak liquors - Molecular characterization of moderately halophilic isolates - GenGank accession number - Cell morphology and pigmentation of moderately halophilic isolates - Effects of NaCl, pH and temperature on moderately halohilic bacterial growth - Enzymatic activities of moderately halophilic isolates - Curing skins with enzyme producing moderately halophilic isolates and storage period - Preparation of stored skin samples for scanning electron microscope - Table 1 : Phenotypic characteristics of the moderately halophilic bacterial isolates DOI : https://doi.org/10.34314/jalca.v118i7.7857 En ligne : https://drive.google.com/file/d/1A42rj9bvYO_w8TZBnVg03im8stsdSJ3g/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39663 [article]

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Tanning with pomegranate peel tannin / Cigdem Kilicarislan Ozkan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 7 (07/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 7 (07/2023) . - p. 301-306 Titre : Tanning with pomegranate peel tannin Type de document : texte imprimé Auteurs : Cigdem Kilicarislan Ozkan, Auteur Année de publication : 2023 Article en page(s) : p. 301-306 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Couleur Cuirs et peaux -- Analyse Cuirs et peaux -- Propriétés mécaniques Ecorces Extraction (chimie) Grenade (fruit) et constituants Tannage végétal Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : By-products of pomegranate juice enterprises are evaluated as a “green” raw material for many industries. In this study, pomegranate peels which are well known with high polyphenolic content were evaluated as a potential source of tanning agent for leather industry. For this purpose, firstly pomegranate peels were extracted in Koch extractor at 70°C for 8 hours. In order to determine the tanning ability, 30% of ground pomegranate peel powder (containing 7.2% of active tannin matter) was used in the tanning process and pomegranate peel tanned leather was evaluated in terms of increases in thickness and shrinkage temperature, color change and mechanical properties. The application of pomegranate peel tannin in the tanning process provided that an acceptable shrinkage temperature (68.5°C) and mechanical properties for vegetable tanned leathers. The results revealed that the tannin obtained from pomegranate peel has a remarkable tanning effect and can be used in the tanning process. Thus, it is concluded that pomegranate peels can be evaluated as a new source of tannin for leather industry. Note de contenu : - MATERIALS - METHODS : Tannin extraction - Tanning with pomegranate peel - Determination of tanning properties of pomegranate peel - RESULTS AND DISCUSSION : Extraction yield and tannin content of pomegranate peel - Tanning properties of pomegranate peel - Color of tanned leather - Mechanical properties of tanned leather - Table 1 : Tanning recipe - Table 2 : Comparison of commercially available tannins and tannin sources - Table 3 : Thickness and shrinkage temperature values of intact pelt and tanned leather - Table 4 : Color measurement values of leather tanned with pomegranate peel - Table 5 : Mechanical properties of leather tanned with pomegranate peel DOI : https://doi.org/10.34314/jalca.v118i7.7860 En ligne : https://drive.google.com/file/d/1vxbGlUneBUgSlPaDgwFVZFO2oju8AJ4t/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39664 [article]

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