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Microscopic study of leather defects / A. L. Everett in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXI (Année 1966)
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Titre : Microscopic study of leather defects : I. Veininess in glazed calfskin Type de document : texte imprimé Auteurs : A. L. Everett, Auteur ; H. J. Willard, Auteur ; J. Naghski, Auteur Année de publication : 1966 Article en page(s) : p. 112-127 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Défauts
Défaut de veine (cuir)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Prominent blood vessel pattern on the grain surface of leather is an esthetic defect which has long been troublesome and costly to the industry. In spite of numerous attempts to solve the problem, as summarized from the literature, the basic cause of the defect remains unknown. Inadequate curing and drastic processing were most frequently suspected, but so far there has been no conclusive proof. Therefore a continuing search for preventive measures would seem less practical than systematic testing of corrective treatments.
Microscopic examination of cross-sections, improved by a suitable aqueous embedding technique, is shown to be helpful in guiding such a program. Studies of blood vessel distribution have established that they are typically arranged in three layers. The deepest and largest vessels, especially the arteries, are the principal offenders in this problem, but it is shown that their depth can be so variable that shaving is not a dependable solution. More significantly, there is almost always a large void space around the deep vessels in veiny leather but not in non-veiny samples, even from skins processed together in the same tannery pack. Thin skins are an especially difficult problem. The suggested approach for correction would be to fill there voids, either by plumping the fibers with a suitable retannage or by the use of impregnating materials. Cross-sections illustrating an experimental zirconium retannage indicate a definite reduction in void space and in consequent veininess. Likewise a resin treatment, being studied elsewhere, seems quite promising af ter preliminary trials.Note de contenu : - EXPERIMENTAL METHODS : Sectioning - Gelatin embedding - Microscopy
- RESULTS AND DISCUSSION : Veiny vs. non-veiny skins - Veiny thin skins -Veniness without void space - Veniness reduced by retannageEn ligne : https://drive.google.com/file/d/1kS5RRAvgc4pKf9T4XiHF_7NrLb0vAQTw/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37939
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXI (Année 1966) . - p. 112-127[article]Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 008496 - Périodique Archives Documentaires Exclu du prêt Microscopical studies in leather manufacture / David Langridge in WORLD LEATHER, Vol. 15, N° 6 (10/2002)
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Titre : Microscopical studies in leather manufacture : Part 1 of 4 : Raw materials Type de document : texte imprimé Auteurs : David Langridge, Auteur Année de publication : 2002 Article en page(s) : p. 70-72 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Animaux domestiques -- Parasites
Cuirs et peaux -- DéfautsIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Animal husbandry practies and their effects upon leather quality are increasingly important areas of research within the leather industry. The work carried out in this field includes correlating parasitic infestation with types of leather damage, and demonstrating the positive correlation between parasite free animals and leather quality, yield and value.
One of the most common types of damage seen on leather is known as light spot or fleck. These are small areas of grain enamel damage which, when dyed, are visible as a lighter colour than the normal regions of the grain due to differential dye uptake. Lightspot, refers to damage 1-3 mm in diameter whilst fleck refers to areas of less than 1 mm.
One of the major difficulties with light spot and fleck damage is the very small area it covers, making it very difficult to see until the leather has been dyed and subsequently dried. As leather is graded after tanning this results in many hides processed for aniline finishing being subsequently downgraded due to hide defects.Note de contenu : - Damage due to lice and stable fly
- Damage due to ticks
- Fig. 1 : Long nosed sucking louse (Linognathus vituli) viewed from the side.
- Fig. 2 : The biting louse (Bovicola bovis) still attached to hair.
- Fig. 3 : The biting louse viewed head on with stage tilted 60° to show the claws and the mouth - claw highlighted.
- Fig. 4 : Stable fly head showing the proboscis used to penetrate the skin, examined with the stage tilted 75°.
- Fig. 5a : Superficial light spot damage caused by lice showing grain enamel erosion.
- Fig. 5b : Light spot damage with distinct boundary edges.
- Fig. 6a : Tick attached to wet blue with the proboscis penetrating into the leather.
- Fig. 6b : Proboscis in detail as it penetrates into the leather, showing the nodules which are believed to secrete an anzyme which aids its penetration into skin.
- Fig. 7 : Tick proboscis in a crosssection of wet blue. Note the barbs used to keep the tick attached to the host.
- Fig. 8 : Disruption caused to the grain surface of wet blue when the proboscis is removed.En ligne : https://drive.google.com/file/d/1-eOHv66NYucTekp-mpavzLNT7HJrbh9u/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32271
in WORLD LEATHER > Vol. 15, N° 6 (10/2002) . - p. 70-72[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 006181 - Périodique Bibliothèque principale Documentaires Disponible Microscopy methods to study fat cells : Part 1 : characterisation of ovine cutaneous lipids using microscopy / V. L. Addy in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 85, N° 1 (01-02/2001)
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Titre : Microscopy methods to study fat cells : Part 1 : characterisation of ovine cutaneous lipids using microscopy Type de document : texte imprimé Auteurs : V. L. Addy, Auteur ; Anthony D. Covington, Auteur ; D. A. Langridge, Auteur ; A. Watts, Auteur Année de publication : 2001 Article en page(s) : p. 6-15 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adipocytes
Cuirs et peaux -- Analyse
Cuirs et peaux de bovins
Histochimie
Lipides
MicroscopieIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Microscopy has been employed to study cutaneous lipids. In particular, light microscopy in conjunction with histochemical labelling techniques and confocal microscopy have been used to determine the chemical basis of the lipid moieties and provide qualitative information regarding the extent to which lipids are deposited within the skin substrate. Furthermore a range of electron microscopy techniques, including a novel cryo-scanning electron microscopy technique, have been used to resolve the structure of the fat cell substrate. Due to inter and intra skin variation, there are difficulties associated with using intact skin as a model for studying adipocytes. Subcutaneous adipose tissue was therefore utilized for studying the morphology of component adipocytes using microscopy. Note de contenu : - Preparation for light microscopy
- Histochemical staining methods
- Confocal microscopy
- Transmission electron microscopy
- Cryo-scanning electron microscopy
- Freeze fracture microscopyEn ligne : https://drive.google.com/file/d/10w3NoQnq4UMVOAKLzo4wis8XO0g8u-dz/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40588
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 85, N° 1 (01-02/2001) . - p. 6-15[article]Microscopy methods to study fat cells - Part 2 : Study of the interaction of ovine cutaneous adipocytes with lipase enzymes using microscopy / V. L. Addy in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 85, N° 2 (03-04/2001)
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Titre : Microscopy methods to study fat cells - Part 2 : Study of the interaction of ovine cutaneous adipocytes with lipase enzymes using microscopy Type de document : texte imprimé Auteurs : V. L. Addy, Auteur ; Anthony D. Covington, Auteur ; D. A. Langridge, Auteur ; A. Watts, Auteur Année de publication : 2001 Article en page(s) : p. 52-65 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adipocytes
Analyse morphologique
Cuirs et peaux -- Analyse
Cuirs et peaux de moutons
EnzymesUne enzyme est une protéine dotée de propriétés catalytiques. Pratiquement toutes les biomolécules capables de catalyser des réactions chimiques dans les cellules sont des enzymes ; certaines biomolécules catalytiques sont cependant constituées d'ARN et sont donc distinctes des enzymes : ce sont les ribozymes.
Une enzyme agit en abaissant l'énergie d'activation d'une réaction chimique, ce qui accroît la vitesse de réaction. L'enzyme n'est pas modifiée au cours de la réaction. Les molécules initiales sont les substrats de l'enzyme, et les molécules formées à partir de ces substrats sont les produits de la réaction. Presque tous les processus métaboliques de la cellule ont besoin d'enzymes pour se dérouler à une vitesse suffisante pour maintenir la vie. Les enzymes catalysent plus de 5 000 réactions chimiques différentes2. L'ensemble des enzymes d'une cellule détermine les voies métaboliques qui peuvent avoir lieu dans cette cellule. L'étude des enzymes est appelée enzymologie.
Les enzymes permettent à des réactions de se produire des millions de fois plus vite qu'en leur absence. Un exemple extrême est l'orotidine-5'-phosphate décarboxylase, qui catalyse en quelques millisecondes une réaction qui prendrait, en son absence, plusieurs millions d'années3,4. Comme tous les catalyseurs, les enzymes ne sont pas modifiées au cours des réactions qu'elles catalysent, et ne modifient pas l'équilibre chimique entre substrats et produits. Les enzymes diffèrent en revanche de la plupart des autres types de catalyseurs par leur très grande spécificité. Cette spécificité découle de leur structure tridimensionnelle. De plus, l'activité d'une enzyme est modulée par diverses autres molécules : un inhibiteur enzymatique est une molécule qui ralentit l'activité d'une enzyme, tandis qu'un activateur de cette enzyme l'accélère ; de nombreux médicaments et poisons sont des inhibiteurs enzymatiques. Par ailleurs, l'activité d'une enzyme décroît rapidement en dehors de sa température et de son pH optimums.
Histochimie
LipasesLes lipases sont des enzymes hydrosolubles capables d'effectuer l'hydrolyse de fonctions esters et sont spécialisées dans la transformation de triglycéride en glycérol et en acides gras (lipolyse). À ce titre, elles constituent une sous-classe des estérases.
Microscopie
Structure cellulaire (biologie)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In Part 1 of this series, a range of microscopy techniques used to study the morphology of the fat cell substrate was described, with a view to developing a better understanding of the degreasing process. This paper discusses how these techniques have been used to study the interaction between the ovine adipocyte substrate with lipid hydrolases. Microscopy has revealed that, under alkaline conditions, the triacylglycerol lipase is able to penetrate the fat cell to effect hydrolysis which is calcium dependent. A striking consequence of this reaction is the morphological changes associated with the adipocyte plasma membrane. These structural changes are thought to be due to the contraction of the plasma membrane, caused by the depletion of the intracellular lipid.
The effect of PLA, hydrolysis on the adipocyte substrate is significant, but mechanistically different to that seen with the triacylglycerol lipase. The deformation of the cell is targeted rather than pervasive, which implies that the phospholipids within the plasma membrane are being hydrolysed. causing pitting and localized deformation of the membrane.
These studies demonstrate that gross cellular changes are associated with the hydrolysis of ovine cutaneous adipocyte derived lipid. This is important evidence to suggest that lipid hydrolases can be used to target and hydrolyse ovine storage lipid.Note de contenu : - EXPERIMENTAL DETAILS : Cryo-scanning electron in microscopy - Transmission electron microscopy - Freeze fracture microscopy - Laser scanning confocal in microscopv - Phospholipase studies
- RESULTS : Study of the interaction of the lipase enzyme with the adipocyte substrate - 1-Histochemical labelling of free fatty acids - Cryo—scanning electron microscopy studies - Transmission electron microscopy studies - Freeze fracture microscopy studies - Confocal scanning microscopy - Phospholipase studies
- Table 1 : Adipocyle cellular structure and histochemical observations for the experimental conditions
- Table 2 : Adipocyte morphology after treating with lead ions to stain the fatty acidsEn ligne : https://drive.google.com/file/d/1wiW1JrOwLWuHDFpsZwszHJaA9KwKPMSx/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40413
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 85, N° 2 (03-04/2001) . - p. 52-65[article]Microscopy of grain defects of bovine leather / Betty M. Haines in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 67 (Année 1983)
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Titre : Microscopy of grain defects of bovine leather Type de document : texte imprimé Auteurs : Betty M. Haines, Auteur Année de publication : 1983 Article en page(s) : p. 25-30 Langues : Anglais (eng) Catégories : Cuirs et peaux -- Défauts Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : At the present time the need to produce full grain and aniline leathers has brought about a greater awareness of grain blemishes and faults. Such faults can originate during the life of the animal, or during cure, or during tannery processing. This paper describes how the microscope, and in particular the scanning electron microscope, is used at BLMRA to identify the cause of grain fault. The illustrations cover a wide. Note de contenu : - The nature of the grain surface : a) Damage during the life of the animal - b) Damage between abattoir and tannery - c) Damage that arises during tannery processing En ligne : https://drive.google.com/file/d/1sMk4pE6MOS_XwGbRwZQ-trDaLVPkW637/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34170
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 67 (Année 1983) . - p. 25-30[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007130 - Périodique Bibliothèque principale Documentaires Disponible Microwave and ultrasound assisted reduction of a benzidine based bis azo dyed leather / Farman Ahmed in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 104, N° 6 (11-12/2020)
PermalinkPermalinkMilling effects on mechanical behaviors of leather / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 6 (06/2007)
PermalinkPermalinkMinimal bactericidal concentration for a quaternary ammonium compound used in soak liquors / Canan Veyselova in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 97, N° 4 (07-08/2013)
PermalinkMinimisation of volatile organics in a metallic foil patent finish for uppers and leather goods / Lluis Ollé in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 93, N° 3 (05-06/2009)
PermalinkPermalinkMinimising the environmental impact of chrome tanning : the "thrublu" process / Samir Das Gupta in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 82, N° 1 (01-02/1998)
PermalinkMinimization of industrial wastes-adding value to collagenic : Adding value to collagenic materials procter memorial lecture / J. Cot in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 3 (05-06/2003)
PermalinkMise en conformité des éclairages aux postes de travail / Cédric Vigier in CTC ENTREPRISES, (04-05/2024)
PermalinkMislabelling of leather is bad business practice in INTERNATIONAL LEATHER MAKER (ILM), N° 35 (05-06/2019)
PermalinkA model for the internal structure of hot pressed leather / A. Wyler in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 75 (Année 1991)
PermalinkModel of the helical portion of a type I collagen microfibril / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCII, N° 1 (01/1997)
PermalinkModeling of strain and filtration properties of a semi-finished leather product / A. Amanov in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 3 (Année 2021)
PermalinkModeling a strategic raw hides & skins supply chain network suitable for adoption of chilling method of preservation in decentralized collection system / P. Anantha Narayanan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 10 (10/2014)
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