Air permeability and moisture penetration performance of leather from a microscopic view / Zhong Anhua in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 99, N° 1 (01-02/2015)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 99, N° 1 (01-02/2015) . - p. 30-32 Titre : Air permeability and moisture penetration performance of leather from a microscopic view Type de document : texte imprimé Auteurs : Zhong Anhua, Auteur ; Jiang Xuewei, Auteur ; Liu Jiajun, Auteur ; Xu Wei, Auteur Année de publication : 2015 Article en page(s) : p. 30-32 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Collagène -- Détérioration Cuirs et peaux -- Analyse Cuirs et peaux -- Détérioration Microscopie Perméabilité Simulation par ordinateur Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In this paper, the microscopic spatial structure change of natural leather collagen Ill (i.e. 1bkv collagen) was simulated using Tinker software. The dynamics of the process for 1bkv [amino acid sequence number of Type III collagen] collagen was simulated at 300K, 320K, 340K and 360K, Through a series of analyses we find that Rg (radius of gyration) of all of the atoms of 1bkv collagen molecules increases with the increase of chosen temperature, and its average value decreases from 24.9Ã… to 21.0Ã…. Considering this along with the simulation trajectory of dynamics at different temperatures, people can find that the molecular chains of collagen gradually will become curved, and there's a large degree of bending at 360K. This is further evidence that the atomic distance between collagen molecules is getting smaller with the increase of the experimental set temperature, and it can also explain the mechanism of performance degradation of natural leather. Note de contenu : - EXPERIMENTAL PRINCIPLE - EXPERIMENTAL TOOLS - RESULTS AND DISCUSSION : Change with time of 1bkv collagen's value of Rg for all the atoms at different temperatures - The trajectory of 1bkv collagen at different temperatures En ligne : https://drive.google.com/file/d/1r-Il8X57OmRFYR_VvW63MCguMFHZyfl4/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23231 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
16961	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Analyzing the mechanism and effect of acid protease in wet blue bating process for leather production / Hao Li in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 1 (01/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 1 (01/2020) . - p. 10-15 Titre : Analyzing the mechanism and effect of acid protease in wet blue bating process for leather production Type de document : texte imprimé Auteurs : Hao Li, Auteur ; Jinzhi Song, Auteur ; Deyi Zhu, Auteur ; Yanchun Li, Auteur ; Shan Cao, Auteur ; Jing Xiao, Auteur Année de publication : 2020 Article en page(s) : p. 10-15 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Biodégradation Chrome Collagène -- Détérioration Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Cuirs et peaux -- Propriétés physiques Desmosine La desmosine est une structure moléculaire formée par l'association de quatre chaînes latérales de lysine. On la retrouve associée à l'élastine où elle forme des interconnexions (liaisons covalentes) entre les différentes fibres et participe ainsi à ses propriétés mécaniques. (Wikipedia) Elastine -- Détérioration Enzymes microbiennes Hydroxyproline Peptidases Résistance chimique Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In recent years, in order to reduce the pollution produced in beamhouse and tanning sections, more and more tanneries purchase wet blue from other factories in other regions directly used as raw materials for finished leather production thereby those polluted preliminary steps can be eliminated. Therefore, the wet blue bating process is an essential step to minimize the differences of wet blue which are purchased from different regions. In this study, the properties of different acid protease are analyzed for selecting suitable protease used for wet blue bating. The analysis of chromium tolerance of different acid proteases reveals that, Ll and L4 produced from Aspergillus have higher chromium resistance than that of produced from Bacillus. The effect of Ll and L4 on wet blue and collagen shows that the Ll has more excellent performance, in which the molecular weight of functional protein is 48 KD. By SEM and MCT analysis, Ll can successfully disperse the collagen fibers of wet blue. Furthermore, the biodegradation rates of collagen and elastin were 0.006‰ and 0.5‰, respectively. It indicates that the acid protease mainly degraded elastin but not collagen in bating process thereby ensuring production safety. This paper provides the importance references for the application and the basis for the development of mechanism of acid protease in bating process. Note de contenu : - EXPERIMENTAL : Materials - determination of chromium tolerance of acid proteases - Pretreatment of wet blue - Physical properties evaluation - Circular dichroism spectrometer analysis - Micro-structure observation - SDS-PAGE analysis - Preparation of enzymatic hydrolysate - Determination of hydroxyproline by HPLC method - Determination of desmosine in the hydrolysate by ELISA method - Calculating the biodegradation rate of collagen and elastin - RESULTS AND DISCUSSION : Chromuim tolerance evaluation - Physical properties analysis - Effect of L1 and L4 acid protease act on collagen - Enzymatic properties of L1 acid protease - Observation of the porosity or dispersion of collagen fiber (bundle) - Analyze the biodegradation rate of L1 to structural protein in wet blue DOI : https://doi.org/10.34314/jalca.v115i1.1463 En ligne : https://drive.google.com/file/d/12pIVNJ4YE3q10psriwZc0l0bZLz6G4M7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33392 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
21484	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Dechroming of chromium-containing leather waste with low hydrolysis degree of collagen / Wei Ding in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 99, N° 3 (05-06/2015)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 99, N° 3 (05-06/2015) . - p. 129-133 Titre : Dechroming of chromium-containing leather waste with low hydrolysis degree of collagen Type de document : texte imprimé Auteurs : Wei Ding, Auteur ; Xuepin Liao, Auteur ; Wenhua Zhang, Auteur ; Bi Shi, Auteur Année de publication : 2015 Article en page(s) : p. 129-133 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chaux Collagène -- Détérioration Cuirs et peaux -- Déchets -- Recyclage Déchromage Hydrolyse Séparation (technologie) Sulfurique, Acide Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Dechroming is essential for utilization of chromium-containing leather wastes. Strong hydrolysis conditions favour breaking of the Cr and collagen linkage, but lead to a high degree of hydrolysis of the collagen se that the separation of chromium from the gelatinous hydrolysates becomes difficult. In this research, a mild acid-alkali alternate treatment of the waste with hydrolysis assistants was investigated, so as to develop a technology that has high dechroming level and low hydrolysis degree of collagen. A satisfactory dechroming method with four steps was finally obtained and the reaction conditions for each step were optimized as follows. Step 1 — waste in the solution with 2g1L NaOH and 40g/L urea {hydrolysis assistant) was stirred for 0.5 hours at 40°C. Step 2 — waste in 50g/L sulfuric acid solution was stirred for 1 heur at 40°C. Step 3 — waste in 40 g/L Cap% suspension was stirred for 2 hour at 30°C. Step 4 — waste in 50g/L suffuric acid solution was stirred for 1 hour at 30°C. With this method, total extent of the dechroming of the waste was higher Chan 97% while the hydrolysis degree of collagen was lower than 10%. Note de contenu : - MATERIALS AND METHODS : Materials - Dechroming procedure of the leather waste - Estimation of the degree of hydrolysis of collagen - RESULTS AND DISCUSSION : Effect of hydrolysis assistant on extent of dechroming - Effect of reaction temperature on dechroming extent - Effect of sulfuric acid concentration on dechroming extent - Effect of calcium hydroxide concentration on extent of dechroming - Hydrolysis degree of collagen En ligne : https://drive.google.com/file/d/190QFQUqFJeTolMygTcMeLAUQr_rYV12n/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24257 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
17271	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Determination of bacterial growth rates and their practical significance / Desmond R. Cooper in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 58 (Année 1974)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 58 (Année 1974) . - p. 25-31 Titre : Determination of bacterial growth rates and their practical significance Type de document : texte imprimé Auteurs : Desmond R. Cooper, Auteur ; A. C. Galloway, Auteur ; D. R. Woods, Auteur Année de publication : 1974 Article en page(s) : p. 25-31 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bactéries -- Croissance Biodégradation Collagène -- Détérioration Cuirs et peaux Peaux brutes Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The growth rates of mixed population of hide bacteria and of pure strains of collagenolytic and non-collagenolytic bacteria have been determinated to show the practical significance of high growth rates in delayed curing and in cured hides. Most of the hide bacteria studied have mean generation times of less than 4 h, which means that under exponential growth rate conditions these bacteria double their number in less than 4 h. This fact and the rate of collagen decomposition by the collagenolytic bacteria can have a significant effect in commercial curing. En ligne : https://drive.google.com/file/d/12bcWOckvbIpPkazWB6l31BTIMggpuf9O/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20429 [article]

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
008594	-	Périodique	Archives	Documentaires	Exclu du prêt

Diffusion and reaction behavior of proteases in cattle hide matrix via FITC labeled proteases / Jianzhong Ma in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 5 (05/2014)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIX, N° 5 (05/2014) . - p. 138-145 Titre : Diffusion and reaction behavior of proteases in cattle hide matrix via FITC labeled proteases Type de document : texte imprimé Auteurs : Jianzhong Ma, Auteur ; Xueyan Hou, Auteur ; Dangge Gao, Auteur ; Jing Zhang, Auteur Année de publication : 2014 Article en page(s) : p. 138-145 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène -- Détérioration Cuirs et peaux de bovins Diffusion (physique) Hydrolyse enzymatique Isothiocyanate de fluorescéine L'isothiocyanate de fluorescéine (FITC, fluorescein isothiocyanate en anglais) est un dérivé de la fluorescéine utilisée dans un large spectre d'applications comme la cytométrie en flux. Le FITC est une molécule de fluorescéine fonctionnalisée avec un groupe réactif isothiocyanate (-N=C=S), remplaçant un atome d'hydrogène sur le cycle le plus bas de la structure. Ce dérivé réagit avec les nucléophiles comme les groupes amines et sulfhydryles des protéines. Un groupe fonctionnel succinimidyle-ester greffé au noyau fluorescéine, créant le NHS-fluorescéine, forme un autre dérivé commun réagissant avec les amines, possédant une plus grande spécificité envers les amines primaires en présence d'autres nucléophiles. Le FITC possède un pic d'excitation et d'émission à 495 nm et 521 nm respectivement. Comme la plupart des fluorochromes, il est sujet au photobleaching. Par conséquent, des dérivés de la fluorescéine tels que l'Alexa 488 et le DyLight 488 ont été optimisés pour des applications chimiques et biologiques nécessitant une plus grande photostabilité, une plus grande intensité de fluorescence ou l'ajout de groupements différents. Peptidases Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Enzymes play an important role in the biological treatment of animal skin collagen in the leather making process. In this work, three proteases (2709, LimeG and SoakL) with different molecular weight were used in the treatment of cattle hide. Protein and hydroxyproline absorbance was measured to evaluate the treatment effectively. Proteases labeled by Fluorescein Isothiocyanate (FITC) were used to treat the cattle hide to observe the diffusion and reaction behavior of proteases in cattle hide matrix. The results indicate that when the cattle hide was treated with smaller molecular weight protease, the degradation degree of the protein and collagen was more than that of the cattle hide treated with larger molecular weight protease. The fluorescence microscopy images demonstrate that during the early stages, proteases chiefly diffused into the cattle hide matrix through pores and hair follicles, and then diffused into the inner layer via hair follicles to hydrolyze inter-fibrillary proteins for opening up collagen fibers. In the present investigation, a visible assessment for the diffusion and reaction behavior of proteases in the enzymatic treatment of cattle hide matrix was reported. Note de contenu : - MATERIALS AND METHODS : Materials - Instrumentation - Determination of the protease activity - Enzymatic treatment of cattle hide matrix - FITC labeled protease - Analysis - RESULTS AND DISCUSSION : Enzymatic treatment of cattle hide matrix - The effect of FITC on the activity of FITC labeled protease - Effect of molecular weights of protease on the diffusion - Diffusion and reaction mechanism of proteases in cattle hide matrix En ligne : https://drive.google.com/file/d/1QDPKDq7Hvzq6ren7nS9eHkiT-NiXMA66/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21285 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
16230	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Effect of chrome tanning on the thermal degradation of hide collagen / K. Takenouchi in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 67 (Année 1983)  

Permalink

Linear relationship Between collagen degradation and degree of swelling in the beamhouse / Zhiwen Ding in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 85, N° 5 (09-10/2001)  

Permalink

Mechanism of collagen processed with urea determined by thermal degradation analysis / Keyong Tang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 10 (10/2020)  

Permalink

Near infrared and two-dimensional correlation infrared spectroscopic study on the heat denaturation of collagen in aqueous solution / Junling Guo in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVII, N° 6 (06/2012)  

Permalink

A new way to treat chrome leather shavings : collagen degradation product as cement retarder / Bangquan Wei in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 105, N° 3 (05-06/2021)  

Permalink

Studies of structure changes of archeological leather by FTIR spectroscopy / Yang Zhang in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 102, N° 5 (09-10/2018)  

Permalink

Studies on the source of contamination of hides by collagenolytic bacteria / D. E. Rawlings in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 58 (Année 1974)  

Permalink

The role of neutral salt for the hydrolysis and hierarchical structure of hide fiber in pickling / Cheng Haiming in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 4 (04/2014)  

Permalink

The role of soaking enzymes on collagen destruction in bovine hide / Thomas H. Feigel in WORLD LEATHER, Vol. 14, N° 6 (10/2001)  

Permalink

Thermal stability and degradation kinetics of vegetable-tanned collagen fiber with in-situ precipitated calcium cabonate / Jie Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIII, N° 11 (11/2018)  

Permalink

Tying up loose ends / Geoff Holmes in LEATHER INTERNATIONAL, Vol. 217, N° 4863 (08/2016)  

Permalink

Vieillissement du collagène pendant la conservation et le stockage des peaux / Wiktor Pietrzykowski in REVUE TECHNIQUE DES INDUSTRIES DU CUIR, Vol. LXVI (Année 1974)  

Permalink

---

1 (1 - 17 / 17)