Preparation and Characterization of Metal Carbide Nanoparticles

Metal carbide (Fe3C) powder has been prepared by a high energed ball mill. The repeated milling of the powder sample leads to lattice distortion which gives rise to microstrains in the lattice. These microstrains increase the contribution of static component of Debye-Waller factor. Thus both lattice strain and the observed Debye-Waller factor, which is the sum of static and thermal components, increase with grinding time. Thus, the resulting nanoparticle powders were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) measurements. The integrated intensities have been measured with a Philips CWU 3710 X-ray powder diffractometer fitted with a scintillation counter using filtered CuK radiation at room temperature and have been corrected for thermal diffuse scattering. Keywords: Fe3C Ball milling, XRD, SEM, lattice parameters, particle size, lattice strain, Debye-Waller factor

Synthesis and Charecterization of Hexagonal Close Packed Fine Nano Particles

Hexagonal close packed zinc nanoparticles were prepared by ball milling method. Zinc powders were ball milled in an argon inert atmosphere. The milled powders were characterized by X-ray diffraction and scanning electron microscopy measurements. Lattice strains in Zn powders produced by milling have been analyzed by X-ray powder diffraction. The lattice strain (e) and Debye-Waller factor (B) are determined from the half-widths and integrated intensities of the Bragg reflections. Debye-Waller factor is found to increase with the lattice strain. From the correlation between the strain and effective Debye-Waller factors have been estimated for Zn. Keywords: Ball milling, X-ray diffraction, particle size, lattice strain, Debye-Waller factor

Dietary Conjugated Linoleic Acid (CLA) Attenuates Hepatic Steatosis by Modifying Stearoyl-CoA Desaturase (SCD-1) mRNA and Activity in High-Fat-Fed Rats

Non alcoholic hepatic steatosis is associated with obesity and may lead to insulin resistance. Isomers of CLA are naturally occurring dietary compounds with health promoting effects. The role of CLA in attenuating hepatic steatosis and hyperglycemia is complex. Here, we investigated the extent that CLA protects male Wistar rats from developing hepatic steatosis. Rats were fed a 20% fat diet for 4 weeks then changed to either control (CON) diet or CLA diet containing 6.5% soybean oil or 5% soybean oil plus 1.5% CLA respectively. After 4 weeks, CLA diet did not change food intake or body weight however fasting blood glucose (FBG) and hepatic triglycerides (TG) were significantly reduced compared to CON group. Reduced TG levels were associated with significantly lower SCD-1 mRNA levels measured by real time PCR and SCD-1 activity which was determined by gas chromatography. As the rate-limiting enzyme in the cellular biosynthesis of oleate and palmitoleate, SCD-1 activity is indicative of synthesis of components of TG, phospholipids and cholesterol. The effects of CLA on SCD-1 were independent of the adipocytokine, leptin, which was unchanged in rats fed CLA. Because leptin is known to suppress SCD-1, these data suggest CLA acts in part as a leptin mimetic. The mRNA levels of gluconeogenic enzymes were unchanged in the CLA fed group. Thus, the lower hepatic lipid accumulation may be modulated by SCD-1 independent of changes on adipose or leptin levels. We anticipate these hepatic effects explain the improvement of glucose levels in Wistar rats fed CLA. This work was supported by the USDA.USD

An Open Framework for Developing Distributed Computing Environments for Multidisciplinary Computational Simulations

Multidisciplinary computational simulations involve interactions between distributed applications, datasets, products, resources, and users. Because the very nature of the simulation software emphasizes a single-computer, small-usership and audience, the kinds of applications that have been developed often are unfriendly to incorporation into a distributed model. However, advances in networking infrastructure, and the natural tendency for information to be geographically distributed place strong requirements on integration of single-computer codes with distributed information sources, as well as multiple computer codes that are geographically distributed in their execution. The hypothesis of this dissertation is that it is possible, via novel integration of Internet, Distributed Computing, and Grid technologies, to create a distributed computational simulation systems that satisfies the requirements of modern multidisciplinary computational simulation systems without compromising functionality, performance, or security of existing applications. Furthermore, such a system would integrate disparate applications, resources, and users and would improve the productivity of users by providing new functionality not currently available. The hypothesis is proved constructively by first prototyping the Enterprise Computational Services framework based on a multi-tier architecture using the Java 2 Enterprise Edition platform and Web Services and then two distributed systems, the Distributed Marine Environment Forecast System and Distributed Simulation System for Seismic Performance of Urban Regions, are prototyped using this enabling framework. Several interfaces to the framework are prototyped to illustrate that the same framework can be used to develop multiple front-end clients required to support different types of users within a given computational domain. The two domain specific distributed environments prototyped using the framework illustrate that the framework provides a reusable common infrastructure irrespective of the computational domain. The effectiveness and utility of the distributed system and the framework are demonstrated by using a representative collection of computational simulations. Additional benefits provided by the distributed systems in terms of new functionality provided are evaluated to determine the impact on user productivity. The key contribution of this dissertation is a reusable infrastructure that could evolve to meet the requirements of next-generation hardware and software architectures while supporting interaction between a diverse set of users and distributed computational resources and multidisciplinary applications