Compressive strength increased progressively on increasing the filler concentration for both silver- and aluminum-filled PMMA. Silane-treated metalized PMMA showed reduction in tensile and flexural strength at 30% concentration. Metalized dentures led to an appreciable increase in thermal perception by the participants of this study.
Several useful composite materials have been developed with natural fiber and plastic matrices, and their commercial viability has been established in terms of adding value to abundant and cheap natural resources. The Macromolecular Research Centre, Jabalpur, India, has recently developed composite from waste newspaper reinforced with plastic material using a prepreg technique wherein the matrix resin consists of resol type phenolic resin (PR) and bifunctional epoxy resin (EP) condensate. Laminates of newspaper and PR‐EP condensate were prepared by hot press molding, and the newspaper weight fraction in these composites was varied from 0.30 to 0.65. The mechanical properties of five selected newspaper (PR‐EP) condensate composites are reported for parameters such as ultimate tensile strength, elongation, tensile modulus, flexural strength and modulus, and heat deflection temperature (HDT). The water uptake behavior of these composites was examined by constructing water absorption isotherms, and the water diffusion coefficient and water absorption (24 h soak test) were determined. The specific tensile and flexural strengths and modulus properties of newspaper‐(PR‐EP) condensate composites are found comparable with one prepared elsewhere from recyclable newspaper‐reinforced polypropylene thermoplastics.
Chloroperoxidase from Musa paradisiaca stem juice has been purified to homogeneity using a concentration obtained by ultrafiltration and anion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The purified enzyme gave a single protein band in SDS-PAGE analysis corresponding to molecular mass of 43 kDa. The native PAGE analysis result has also given a single protein band, confirming the purity of the enzyme. The purified enzyme was chlorinated and brominated with monochlorodimedone, the substrate used for measuring the halogenating activity of chloroperoxidases. The K m and k cat values using monochlorodimedone as the substrate were 20 μM and 1.64 s −1 , respectively, giving a k cat /K m value of 8.2 × 10 4 M −1 s −1 . The pH and temperature optima of the chlorinating activity were 3.0 and 25 • C, respectively. The K m values for the peroxidase activity using pyragallol and H 2 O 2 as the variable substrates were 89 and 120 μM, respectively. The pH and temperature optima of the peroxidase activity using pyrogalllol as the substrate were the same as the pH and temperature optima of the halogenating activity. The peroxidase activity of the enzyme is competitively inhibited by sodium azide, indicating that it is a hemeperoxidase different from nonheme peroxidases.
Lignin peroxidase from the culture filtrate of Loweporus lividus MTCC‐1178 has been purified to homogeneity using Amicon concentration and DEAE cellulose chromatography. The molecular weight of the purified lignin peroxidase using SDS‐PAGE analysis has been found to be 40 kDa. The Km values for veratryl alcohol and H2O2 for the purified enzyme were 58 and 83 μM, respectively. The calculated kcat value of the purified enzyme using veratryl alcohol as the substrate was 2.5 s−1. The pH and temperature optima of lignin peroxidase have been found to be 2.6 and 24°C, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.