The role of adenine nucleotides and their derivatives in the control of liver metabolism

Imperial Users onl

Studies on the thermoluminescence glow curves of Mn doped ZnS nanoparticles

This paper reports the synthesis of ZnS nanoparticles doped with Mn using mercaptoethanol (ME) as the capping agent. The particle size of such nanoparticles were measured by X-ray diffraction technique (XRD) and by the Transmission electron microscopy (TEM) patterns and were found to be in between 2nm - 6nm. For the samples with different concentration of the capping agent, it was found that the thermoluminescence (TL) intensity of ZnS:Mn nanoparticles increased as the particle sizes were decreased. The shift in peak position of TL glow curve was also seen with decreasing particle size

Structural and optical characterization of ZnS nanoparticles

The present paper reports the structural and optical characterization of the ZnS nanoparticles, where as mercaptoethanol (ME) was used as the capping agent. Nanoparticles of zinc sulphide were prepared by chemical route technique. The particle size of such nanocrystals was measured using XRD pattern and it is found to be in between 3nm - 5nm. The blue-shift in the absorption spectra was found with reducing size of the nanoparticles. It was also found that the change in Mn concentrations does not influence the particle size and blue-shift in the absorption spectra. The optical absorption edge was found at 280 nm for all the doped samples for fixed concentration of capping agent. The particle size of nanoparticle has been calculated both theoretically and experimentally, which is nearly the same. The FTIR spectra inferred that the stabilizing agent passivates the surface of the particles

Relaxations in Complex Polymer Systems

Many applications that employ polymeric materials rely on mixtures (polymer/polymer, polymer/nanoparticle, polymer/filler). A key challenge of using these materials is understanding interrelations between the physical properties and the local and macroscale morphologies. The most common systems are mixtures of two homopolymers, A and B, which can exhibit properties that are more desirable than those of the pure components. Unlike miscible small molecule systems, miscible A/B polymer/polymer blends, while macroscopically homogeneous, can be spatially compositionally heterogeneous at the molecular level, which can cause deviations in physical properties. Applications in the areas of organic electronics, membranes, and nanoscale coatings can also require these materials to function under various conditions of geometric confinement, such as thin films. This introduces an additional complication because the proximity to an external interface (free surface or substrate) influences the local composition and morphology, leading to film thickness-dependent behavior. To this end, this dissertation explores three problems involving the role of morphology on dynamic processes in polymeric systems of different local intermolecular environments. First, we investigate the role of local spatial compositional heterogeneity on the dynamics of the A component in bulk, miscible A/B polymer/polymer blends. The dynamics of the faster, lower glass transition temperature component A, at temperatures sufficiently high above the blend glass transition, manifest the behavior of chains relaxing in a compositionally homogeneous environment. For temperatures lower than the blend glass transition, the A component chains relax in two distinctly different local compositional environments, manifesting the influence of spatial compositional heterogeneity. Having investigated the role of spatial compositional fluctuations on the relaxations of the A component in A/B polymer/polymer blends, the additional effect of geometric thickness confinement at the nanoscale – confining the A/B mixture between two substrates – was studied. In thin film blends, the concentration of the A component may differ from the macroscopic average composition at different depths into the film, largely due to its preferential interactions with the confining substrates. In this case, the compositional changes driven by the interfacial interactions become dominant when the films are sufficiently thin. A key finding is that, whereas thickness confinement effects modify the dynamics of pure homopolymer chains for thicknesses up to a few nanometers, the effects on these A/B blends extend over hundreds of nanometers. The third problem is based on the recognition that in most applications, polymer thin films can be required to contact other polymers or different “hard” materials. The vast majority of studies that investigate physical properties examine either free or supported films. Here we investigate the dynamics of a homopolymer A confined between a hard substrate C and a soft, immiscible polymer film B. A surprising finding is that the presence of the soft polymer B has the effect of increasing the relaxation rates of polymer A significantly, and over unusually large length-scales, not observed in polymers confined between two hard substrates C. These findings implicate the sensitivity of polymer dynamics to the modulus of the confining environment. The works described in this dissertation provide a comprehensive view of how physical properties of polymers can change significantly in different environments – compositional changes, changes in mechanical moduli of the surrounding environment, and geometric constraints. Insights gained from these studies can be used to understand and control the physical properties of polymer-based materials for future applications.PHDMaterials Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/143918/1/rpsharma_1.pd

Myconanotechnology and application of nanoparticles in biology

To develop a new green approach for biosynthesis of nanoparticles, myconanotechnology has been represented as a novel field of study in nanotechnology. Several scientists have re-explored the fungi including yeasts and filamentous fungi as a biofactory for eco-friendly, cost-effective synthesis of nanoparticles. The advantageous of fungal-mediated biosynthesis of nanoparticles have turned the attention of scientists to the kingdom of fungi. The most notable benefits of applying fungi in nanoscience are their resistance to many harsh conditions as well as secretion of extracellular reductive proteins so that it makes the downstream processes easier. This review focuses on general introduction, synthesis of nanoparticles through fungi and its application in biology

Analysis of Mobile Services and Their Impact on Economic Development

The primary aim of this paper is to analyze user’s adoption of mobile data services under various circumstances. The data for this paper has been obtained from the Worldwide Mobile Data Services (MDS) Survey (Sharma et al, 2014). This research paper also characterizes devices, usually identified as smart phones. Smart phones are sophisticated tools (devices), which can be used for I/O (input/output), processing, storage and for broadband connectivity. The features and functionality of these devices range widely, facilitating browsing the internet as well as applications that utilize authentication, location detection and multitasking. Such features that MDS provides us have become an inexorable part of our lives. These devices offer us so much that all forms of work and leisure activities that are routine in our day-to-day deeds progressively depend more on them. As a result, the providers of MDS[14] nowadays offer a superfluity of both products and services, which empower patrons to perform a range of work and leisure tasks that are correlated with commercial transactions, networking and communication, information access and content downloading (Garbacz and Thompson, 2007). This is an integral part of the era of ubiquity