Browsing by Subject "Substrate"
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Item A rapid quantitative assay for bacterial protease activity(2006-08) Hien, Nguyen Thi Phuoc; Shelly, Dennis C.; Weber, JoachimA rapid quantitative stained hide powder assay was studied as a possible replacement for the gelatin film test, used to detect bacterial enzymes within hide juice of delayed cured hides. The ability of the method was investigated by employing different kinds of substrates and enzymes. Substrates from dogchew and rawhide were hydrolyzed by Proleather FG-F, Protex 6L and Alcalase enzyme under optimum conditions. Reproducibility of the dogchew substrate was higher but hydrolysis efficiency was less than for the rawhide substrate. To improve reproducibility and hydrolysis efficiency, a stable, neutralized stained hide powder was produced and served as a substrate for calibration. Analytical figures of merit are described. The relations between the efficiency of hydrolysis and enzyme concentration or enzyme activity were linear. The effect of salt shifted the calibration toward lower hydrolysis efficiency. The slopes did not change. The method could detect the Proleather FG-F enzyme concentration as low as 0.01 ìg/ml or enzyme activity of 1.01x10-3 LVU/ml without salt and 0.05 ìg/ml or enzyme activity of 5.05x10-3 LVU/ml with salt.Item A rapid quantitative assay for bacterial protease activity(Texas Tech University, 2006-08) Hien, Nguyen Thi PhuocA rapid quantitative stained hide powder assay was studied as a possible replacement for the gelatin film test, used to detect bacterial enzymes within hide juice of delayed cured hides. The ability of the method was investigated by employing different kinds of substrates and enzymes. Substrates from dogchew and rawhide were hydrolyzed by Proleather FG-F, Protex 6L and Alcalase enzyme under optimum conditions. Reproducibility of the dogchew substrate was higher but hydrolysis efficiency was less than for the rawhide substrate. To improve reproducibility and hydrolysis efficiency, a stable, neutralized stained hide powder was produced and served as a substrate for calibration. Analytical figures of merit are described. The relations between the efficiency of hydrolysis and enzyme concentration or enzyme activity were linear. The effect of salt shifted the calibration toward lower hydrolysis efficiency. The slopes did not change. The method could detect the Proleather FG-F enzyme concentration as low as 0.01 ìg/ml or enzyme activity of 1.01x10-3 LVU/ml without salt and 0.05 ìg/ml or enzyme activity of 5.05x10-3 LVU/ml with salt.Item Wrinkling of Stiff Films on Stretched Compliant Films: Experimental and Theoretical Studies(2013-12-06) Yang, YiWrinkling of stiff film on semi-infinite compliant substrates has attracted attentions recently due to its important applications in stretchable electronics and micro-pattern metrology. However, wrinkling of a stiff film on a compliant thin film substrate has not been well understood. The composite bilayer comprised with a stiff film and a stretched film has a critical application in developing advanced thin film solar cells for long duration stratosphere balloons. The presented thesis focuses on wrinkling of stiff films with finite widths on stretched compliant thin sheet via experimental and theoretical approach. Polyester films and low density polyethylene films have been utilized as the surface films and substrate films, respectively. Flexible polyvinyl chloride films have also been employed to serve as the surface layer for better understanding the physics behind the phenomena. The experiments reveal wrinkling phenomena of the film on the stretched thin sheet are very similar to that of a stiff film on a semi-infinite elastic foundation. A theoretical model considering finite width effect is formulated based on the concept of effective elastic foundation observed from the experiments via variational approach and principle of minimum potential energy. The result predicted by the theoretical model is validated via experiments and the finite width effect is also investigated and discussed. In summary, the presented study shows the stretched film plays the role as a virtual semi-infinite elastic foundation for the surface film. The experimental ob- servations and theoretical prediction of the phenomena has been achieved. It may provide a physics-based foundation for technology adventures in thin-film solar cell powered scientific balloon.