Commercial crystalline fructose is currently prepared by chromatographic separation of aqueous solutions of fructose and glucose followed by crystallization in either aqueous or aqueous−ethanol solutions. It may be possible to use one or more crystallization steps instead of the chromatographic process, thus producing crystalline product more directly. In this study the solubility, refractive index, and viscosity of solutions of fructose + glucose + ethanol + water were measured at 30 °C, and the densities of solutions with solvent concentrations of 40, 60, and 80 mass % ethanol were measured at 25 °C. These properties will be useful for crystallization studies for this system.
[Show abstract][Hide abstract] ABSTRACT: Ethambutol (EMB) is a bacteriostatic antimycobacterial drug prescribed to treat tuberculosis. It is bacteriostatic against actively growing TB bacilli. The density and viscosity of aqueous ethambutol hydrochloride solutions have been studied at 298.15, 301.15 and 304.15 K and at different concentrations (0.255, 0.168, 0.128, 0.087, 0.041, and 0.023 mol dm−3). The apparent molar volume of these solutions for different temperatures and concentrations was calculated from the density data. The relative viscosities of drug solutions have been analysed by Jones-Dole equation. The limiting apparent molar volumes have been evaluated for different temperatures. The different properties have been used to study structural properties, structure formation and breaking properties of drug and solute-solvent interactions in solutions.
[Show abstract][Hide abstract] ABSTRACT: The nonsurfactant templated sol–gel route has been demonstrated to be a cost effective, green and biofriendly pathway to obtain mesoporous materials with an interconnected network of wormhole–like pores. It involves the formation of a metal–oxide network around an inert organic molecule (e.g., sugar molecules) which functions as a template and can be later removed by simple extraction with water or other solvents. This research describes the preparation of mesoporous zirconia and organo–functionalized silica by the acid–catalyzed nonsurfactant templated sol–gel route and also describes the use of sublimation as a method for the template removal. Mesoporous silica nanospheres with tunable particle size were also prepared by modifying the base–catalyzed Stober process with the addition of various sugar molecules as templates. The materials were characterized using TGA, nitrogen adsorption–desorption, SEM, TEM, XRD and FTIR. The application of nonsurfactant templated mesoporous materials in the area of enzyme encapsulation and stabilization is explored in this research. A novel ‘double encapsulation’ approach that enables a sol–gel encapsulated protease to retain 60 % of its original activity after 4 weeks in harsh environments, such as high pH buffer and laundry detergent, is demonstrated. The need for aesthetic, as well as durable, dental restorations has led to extensive research in the area of dental composites. This study examines the use of nonsurfactant templated mesoporous materials as fillers in dental composites. Mesoporous materials of irregular morphology prepared by acid–catalyzed sol–gel routes as well as mesoporous silica spheres prepared via base–catalyzed sol–gel reactions were both employed as fillers in experimental dental composites. This research led to the development of novel ‘dental monomer templated mesoporous materials’, which were also evaluated as fillers in dental composites. Various approaches, such as dense packing, addition of nanosilica and spherical fillers, etc., were employed to fabricate nanocomposites with improved mechanical properties. The composites were evaluated using flexural and compression testing. Curcumin, the ground rhizome of Curcuma longa, a common South Asian herb has attracted much attention due to its chemopreventive and anti–inflammatory properties. This research describes the synthesis of a series of poly [(arylenedioxy)(diorganylsilylene)]s via polycondensation between curcumin and various diorganodichlorosilanes. These novel polymers incorporate the β–diketone unit of curcumin as well as the Si–O bond in the backbone. The polymer structure was characterized by means of 1HNMR, FTIR and elemental analysis, while GPC results showed high molecular weights. Preliminary cell culture results suggested lack of cytotoxicity, which is important for potential applications, such as implants and tissue engineering scaffold materials. The unique and interesting thermal behavior of these polymers was studied by DSC. The technology of enzymatically degrading biomass into simple sugars, such as glucose, is a critical step towards viable production of bio–based ethanol from non–food related sources. This research demonstrates the use of a biosensor–based diabetic blood glucose monitor as a rapid glucose detector and compares it to time consuming UV assays that are currently employed in research laboratories. Pretreatment of wood shavings with ferric chloride, followed by treatment in cold NaOH/urea solution was found to significantly enhance glucose production upon enzymatic hydrolysis. Finally, accounts of exploratory experiments in the areas of thermally crosslinkable high temperature elastomers and inorganic–organic hybrid materials are provided in the appendix sections of this thesis.
[Show abstract][Hide abstract] ABSTRACT: Routing FPGAs is a challenging problem because of the relative scarcity of routing resources, both wires and connection points. This can lead either to slow implementations caused by long wiring paths that avoid congestion or a failure to route all signals. This paper presents PathFinder, a router that balances the goals of performance and routability. PathFinder uses an iterative algorithm that converges to a solution in which all signals are routed while achieving close to the optimal performance allowed by the placement. Routability is achieved by forcing signals to negotiate for a resource and thereby determine which signal needs the resource most. Delay is minimized by allowing the more critical signals a greater say in this negotiation. Because PathFinder requires only a directed graph to describe the architecture of routing resources, it adapts readily to a wide variety of FPGA architectures such as Triptych, Xilinx 3000 and mesh-connected arrays of FPGAs. The results of routing...
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