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Heat-treated Samples (heat-treated + sample)
Selected AbstractsInhibition of bacteriophage K proliferation on Staphylococcus aureus in raw bovine milkLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2005S. O'Flaherty Abstract Aims:, To assess the ability of staphylococcal bacteriophage K to inhibit Staphylococcus aureus in raw milk. Methods and Results:, The ability of bacteriophage (phage) to replicate in milk is important in situations where phage might be used as a therapeutic for bovine mastitis. Phage K was able to replicate normally, leading to elimination of the host culture in milk, which had been previously heat-treated. When raw milk was used under identical conditions, the phages were unable to replicate. Phage adsorption assays were performed and these demonstrated that adsorption of phage was significantly reduced in the raw milk while it was restored in the heat-treated sample (86·50% compared with 99·96% adsorption respectively). When confocal microscopy with a Live/Dead Bac light staining system was employed, it was observed that in raw milk S. aureus formed clusters associated with fat globules, while in heat-treated milk, bacterial agglutination had not occurred. Conclusions:, Raw milk inhibits staphylococcal phage K proliferation. Significance and Impact of the Study:, This observation has implications for the exploitation of staphylococcal therapeutic phage in milk. [source] Effect of Microstructure on High-Temperature Compressive Creep of Self-Reinforced Hot-Pressed Silicon NitrideJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2000Martha A. Boling-Risser An experimental self-reinforced hot-pressed silicon nitride was used to examine the effects of microstructure on high-temperature deformation mechanisms during compression testing. At 1575,1625°C, the as-received material exhibited a stress exponent of 1 and appeared to deform by steady-state grain-boundary sliding accommodated by solution-reprecipitation of silicon nitride through the grain-boundary phase. The activation energy was 610 ± 110 kJ/mol. At 1450,1525°C for the as-received material, and at 1525,1600°C for the larger-grained heat-treated samples, the stress exponent was >1. Damage, primarily in the form of pockets of intergranular material at two-grain junctions, was observed in these samples. [source] Hot air treatment decreases chlorophyll catabolism during postharvest senescence of broccoli (Brassica oleracea L. var. italica) headsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2006Maria L Costa Abstract A hot air treatment was applied to broccoli (Brassica oleracea L. var. italica) florets and its effect on chlorophyll catabolism during postharvest senescence was analyzed. Florets were treated at 48 °C for 3 h and then placed in darkness at 20 °C. During storage, the yellowing of florets occurred simultaneously with a decrease in chlorophylls and an increase in pheophytins. Heat treatment delayed the appearance of yellowing by 2,3 days and a similar extension of shelf-life could be inferred. Also, the treatment delayed the onset of chlorophyll catabolism and slowed both the rate of chlorophyll a degradation and pheophytin accumulation. No effect on chlorophyll b degradation was found. Chlorophyllase and Mg-dechelatase activities increased from the first day of storage in untreated florets, whereas peroxidase-linked chlorophyll bleaching activity increased from day 3. In heat-treated florets, chlorophyllase activity did not increase until day 2 and then increased at lower rate than in controls. Mg-dechelatase and peroxidase-linked chlorophyll bleaching activities were similar in treated and control florets during the first 2 days of storage, but thereafter the activity of both enzymes was lower in heat-treated samples. In conclusion, a treatment at 48 °C for 3 h delayed chlorophyll a catabolism in broccoli during postharvest senescence and decreased the activities of chlorophyllase, Mg-dechelatase and peroxidase, three of the enzymes probably involved in chlorophyll degradation in plants. Copyright © 2006 Society of Chemical Industry [source] Comparative Study of the Carbonisation of CoTMPP by Low Temperature Plasma and Heat TreatmentPLASMA PROCESSES AND POLYMERS, Issue 6 2010Iris Herrmann Abstract Low temperature plasma (LTP) treatment of cobalt-tetramethoxyphenylporphyrin (CoTMPP) has been applied as a promising alternative method to the conventional heat treatment in order to attain highly active catalysts for the electroreduction of oxygen. In this contribution it is shown that CoTMPP can be completely transformed into a carbon matrix by adjusting adequate LTP parameters. The carbonisation process of CoTMPP is investigated at different operation conditions by Raman and IR spectroscopy and compared with the structural features of the heat-treated samples. As a result it appears that the LTP occurs via a different carbonisation process, which yields in a more homogeneously defined molecular carbon structure. [source] | ||||||||||