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In this study, decolorization via a bleaching operation was carried out on chrome and dye spotted skins with several bleaches to valorize the defective leather materials. Sodium perborate, hydrogen peroxide, sodium thiosulfate, sodium percarbonate, and oxalic acid were applied as bleaching agents in production. Sodium perborate by itself was applied and combined with other bleaching agents. Combined processes were also supported with an emulsifier agent for uniform distribution and deeper penetration of bleaching agents into the fibers. Color changes and differences on leather products were determined by Konica Minolta CM-3600d test apparatus spectrophotometrically before and after the applications. Bleached leathers were processed again, re-dyed, and finished after the bleaching operations. Then, bleaching performances of the single and combination applications were also evaluated for the leather strength indicators by analyzing tensile and tear strength of the final products as well as chromium (VI) oxidation of basic chromium (III) salts used in tanning. Antibacterial properties of the final bleached products were also investigated. As a result, sodium perborate was found to provide the most effective and safe bleaching without any physical and chemical deformation by creating antibacterial activity on leather. [ABSTRACT FROM AUTHOR]

In this study, collagen hydrolysate from bovine shaving wastes of leather production with the alkali hydrolysis reaction was emulsified with amino functional silicone oils to prepare lubricating natural polymer (LNP). Particle size and zeta potential of the LNP were measured. Prepared LNP was used in the fatliquoring step of chromium tanned bovine leathers. Contact angle of the leather surfaces with water were employed to study hydrophobicity of treated leather. The water absorption behavior of leather was determined by dynamic water resistance (penetrometer test) and static water resistance tests (kubelka water up-take). Performance characterizations of leathers were carried out with tensile strength, tear strength, filling efficiency and water vapour permeability (WVP) analyses. The contact angle measurements showed that the hydrophilic property of leather surface decreased after LNP treatment. Both dynamic and static water absorption behaviour was lowered while the WVP of leathers was not significantly affected negatively except of 20% LNP. Only 20% LNP application slightly decreased the WVP of leathers. Moreover, new lubricating agent provided satisfactory strength performance and good filling effect on leathers.

In this study, collagen hydrolyzate was obtained from bovine shaving wastes of leather production with the alkali hydrolysis reaction. Total amino acid, total carbon and total nitrogen amounts of liquid collagen hydrolyzate (CH) were determined. Fourier-transform infrared spectroscopy (FTIR) characterization of collagen hydrolyzate was performed. Obtained CH was emulsified with hydrogenated castor and amino functional silicone oils to prepare lubricating protein filler (LPF). Particle size and zeta potential of the LPF were analyzed. 10%, 15%, and 20% LPF was used in the retanning/fatliquoring process of chromium tanned bovine leathers. Performance characterizations of leathers treated with LPFs were carried out with tensile strength, tear strength, filling efficiency, light fastness, shrinkage, and denaturation temperature analyses. Moreover, bounded fat content in leather was also determined. Results showed the increased thermal stability, strength performance and good filling effect in leather by application of the prepared LPF. Consequently, LPF had a good potential as natural retanning/fatliquoring agent via achieving reuse of the solid leather wastes and providing satisfactory leather properties and cleaner production by one product itself. [ABSTRACT FROM AUTHOR]

In this study, the antibacterial fatliquor emulsion was prepared from castor oil bearing thymol (1, 2, 4 and 8% w/w) to be used in the leather production. The average particle size and zeta potential of the fatliquors were determined by zeta sizer. The thermogravimetric behaviors of fatliquor emulsions under dry air were analyzed in order to determine the weight losses when they are exposed to constant heating rate. After the emulsification process, fatliquor emulsions were applied into chrome tanned cattle leathers. Antibacterial activities of the fatliquored leather were tested according to standard test method for determining the antimicrobial activity under dynamic contact conditions against Gram-positive and Gram-negative bacteria. Minimum inhibitory concentration (MIC) analysis of emulsion was also determined. The bacterial reduction was measured as 99.9% against S. aureus and 98.6% against E. coli bacteria. MIC values obtained from emulsions against bacteria were determined as 6.25 μL/mL and 12.5 μL/mL respectively. The results of antibacterial tests showed that thymol was very efficient in the fatliquor emulsion against both Gram-positive bacteria and Gram-negative bacteria. Physical characterization of leather was also carried out with optimum fatliquor emulsion (4% thymol w/w) and the results showed satisfactory physical properties on the fatliquored leathers compared to similar leather made with commercially available fatliquors. The results of the study indicated that thymol loaded fatliquor emulsions with small particle size could be a promising solo fatliquor to provide functional properties such as physical, strength, morphological and antibacterial properties to leather as an efficient fatliquor compared to conventional fatliquors. [ABSTRACT FROM AUTHOR]

Objective: To investigate if there are any advantages in using intracoronary shunts compared to shuntless operations, in the context of whether it has a protective role for the myocardia., Methods: This prospective study, included 100 patients who underwent off-pump coronary bypass surgery at 2 different cardiovascular surgery departments, namely, the Social Security Ankara Ihtisas Hospital, and Hacettepe University Hospital, Turkey, between September 2002 and July 2006. Patients were divided into 2 groups. In group 1 n=50 off-pump coronary bypass operations were performed with intracoronary shunts. In group 2 n=50 shunts were not used during off-pump. Serum creatine kinase, myoglobin, and troponin were studied., Results: There were significant increases in serum creatine kinase levels in group 2 at postoperative 6th, 12th, and 24th hours. In group 2, the increase of myoglobin was statistically significant at only the postoperative 24th hour. Troponin levels were significantly higher in group 2 at postoperative 6th, 12th, and 24th hours., Conclusion: There are some questions regarding myocardial protection while maintaining a bloodless secure surgical field in off-pump coronary surgery. However, use of intracoronary shunts provides distal coronary flow, and reduces the risk of myocardial ischemia, while maintaining a comfortable blood free anastomosis area.