Lam Wai-yean. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1978. / Bibliography: leaves 108-109.

Thesis (M.S.)--University of Nevada, Reno, 2005. / "December, 2005." Includes bibliographical references. Online version available on the World Wide Web.

Thesis (Ph. D.)--University of Nevada, Reno, 2005. / "December 2005." Includes bibliographical references. Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.

Five commercial metal oxide nanoparticles (CuO, SiO2, Fe2O3, TiO2 and Al2O3) have been individually screened for mercury removal in a batch reactor under bicarbonate buffered and non-buffered aqueous solutions (DI water). Copper oxide was then selected for surface modification to enhance mercury removal. The surfaces of both laboratory prepared and commercially available copper oxide nanoparticles were treated with 1-octanethiol to produce copper sulfide and/or copper alkanethiol nanoparticles. The resulting particles were characterized using X-Ray Fluorescence(XRF), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The novel nanoparticles demonstrated very high mercury removal (> 99%) from both the buffered and non-buffered aqueous solutions.

The purposes of this study are to evaluate and elucidate distribution patterns, speciation and pollution status of As and Hg in coastal sediments. The study focuses on coastal zones off southwestern Taiwan including the Kaoping River estuary, the Kaoping Canyon, Chiku and Tapong lagoons. Experimental results show that As and Hg in surface sediments from the Kaoping River estuary are mainly associated with mud (clay+silt) and TOC. They may also co-precipitate with Fe-Mn oxides/ hydroxides in sediments. Consequently, the seasonal variability of As and Hg distributions in estuarine sediments is likely attributed to the variations of particles size and TOC contents. Distributions of As in surface sediments from the Kaoping Canyon are also related closely to mud, Fe-Mn oxides and TOC contents. The spatial variation of surface enrichment of As, however, is insignificant along the Kaoping Canyon. Concentrations of Hg in surface sediments are elevated around the river mouth and decrease seaward in the Kaoping Canyon. According to As and Hg distributions and accumulation rates in the Kaoping Canyon, pollution appears to increase significantly around 1970 corresponding to the period of economic boom in Taiwan. With the exception of locations near the Chiku River and Daliao Creek, spatial distributions of As and Hg are largely determined by particle size, organic and Fe-Mn contents. In the Tapong Bay, concentrations and enrichments of As and Hg are generally higher in the inner bay than in the outer bay, primarily affected by distributions of particle size, organic and Fe-Mn contents. The enrichment of Hg in the inner bay appears to be enhanced by waste-water discharge, TOC accumulation and sulphide formation. The magnitudes of EF are larger in the Tapong Bay than in the Chiku Lagoon and the Kaoping River estuary for both As and Hg, indicating a higher pollution status in the Tapong Bay than in other areas. Sequential extractions separate As and Hg into five fractions that can be roughly divided into mobile phase and non-mobile phase (residual fraction). The sum of mobile-like fractions is significantly correlated with the content extracted with 0.1M HCl. Arsenic and mercury speciation of sediments are quite similar in the Kaoping River estuary, the Chiku Lagoon and Tapong Bay. Both As and Hg are mostly concentrated in the residual fraction, and secondly located in Fe-Mn oxides for As, and in organic matter for Hg. Arsenic and mercury speciation in sediments are apparently not controlled by the variability of salinity in the estuary.

Trimeric perfluoro-ortho-phenylene mercury (1) constitutes one of the simplest trifunctional Lewis acidic hosts. Cooperative effects arising from the proximity of the mercury(II) centers, the electron-withdrawing properties of the backbone and the accessibility of the electrophilic sites leads to the facile complexation of neutral and electron rich substrates. The planarity of the structure as well as its overall polarizability compounded with relativistic effects at mercury also permits the occurrence of non-covalent interactions. The main objective of this dissertation was to explore the potential of 1 as a building block for supramolecular materials. Compound 1 was investigated using single crystal x-ray diffraction and was found to display a rich polymorphism. The electronic structure, probed by DFT methods, shows that the LUMO of 1 has a large contribution from the mercury 6p orbitals and features a large lobe protruding above and below the center of the trinuclear mercury core. Complexes in which two nitronyl nitroxide radicals (NIT-Ph = 2-(phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) coordinate to the trinuclear core of 1 above and below the Hg3 plane reveal that 1 does not significantly mediate magnetic interactions. The ability of 1 to complex π-basic molecules such as tetrathiafulvalene (TTF), toluene, o-xylene, m-xylene, p-xylene, mesitylene, biphenyl, naphthalene, acenaphthalene, anthracene, pyrene, triphenylene, perylene, and coronene was also investigated and show that 1 and arenes form extended binary stacks in which the two components alternate. The photoluminescence observed in some of these supramolecular complexes corresponds to the phosphorescence of the arene indicating a mercury heavy atom effect. Complexation of 1 in solution was observed with hexaalkoxytriphenylenes (HATn, n = 1, 6) by fluorescence and NMR spectroscopy. Finally, compound 1 forms electrophilic double sandwich structures with ferrocene and nickelocene in which a molecule of 1 caps each of the Cp ligands. The nickelocene adduct is stabilized towards oxidation, and the photophysical and magnetic properties indicate the occurrence of a mercury heavy atom effect.

By considering examples of representations of AIDS from across the cultural spectrum the thesis addresses the processes by which a popular understanding of the condition in this country has been constructed. Whilst many of the representations do not originate in the UK the increasing level of communicative interaction of global culture mean that there is a constant exchange across national boundaries, as there is across many other discourses, but which at particular moments have a local impact which can be considered in itself. In the light of this, the thesis considers representations circulating within the realms of: advertising and photography centred on the photograph of David Kirby taken by Therese Frare, newspaper coverage of the death of Freddie Mercury, Hollywood film including Philadelphia, health education advertisements, and art through a series of paintings by Derek Jarman. The starting point for this process in each chapter is the analysis 'of specific iconic images positioned within particular discursive frames. AIDS, as a socially significant locus of meaning around issues of disease and sexuality rather than just a strictly medical syndrome of opportunistic diseases, has so far been largely confined to the mediated realm of representation for many people in this country. Because the constituency most affected in this country is that of Gay men these representations have been continuously shaped by broader ideological concerns relating to issues of power, sexuality and legitimacy. To develop a useful sense of the implications of this across the cultural spectrum and to offer a contribution to the field of knowledge the thesis addresses the primary sites of media culture that people engage with on a regular basis to offer a reading not confined to one discursive order. From such an analysis an assessment is made of those factors that can be seen to articulate an understanding of the condition beyond the limits of anyone cultural formation working within the matrix of the dominant cultural order

Diffusive gradients in thin film (DGT) technique is applied to determine pore water mercury concentrations in river sediments. DGT devices have been a useful indicator of dissolved metals in aqueous systems, although it is not as well developed for measuring mercury. DGT devices were evaluated for three different ion exchange resins for adsorption of mercury. After a series of laboratory experiments, 3-Mercaptopropyl Functionalized Silica Gel (3M) was chosen as an effective resin layer. Laboratory experiments showed that the resin strongly associated with dissolved Hg²⁺. DGT probes were tested with sediments from the South River (Virginia, USA) in the laboratory and the time dependent deployment verified an uptake of mercury to the probes and established an effective diffusion coefficient for site specific utilization. Multiple piston and sediment probes were deployed in the South River in-situ to determine overlying water Hg concentrations and sediment pore water Hg concentration profiles. The DGT devices were successful in measuring Hg concentrations in-situ. / text

No description available.

Mercury exposure has been related to neurological diseases and poisoning. Quantification of mercury in biological fluids, such as serum or urine is an important diagnostic method for mercury exposure. We have developed an aptamer-encapsulated porous phospholipid nanoshell (PPN) sensor for sensing mercury in urine using a modified 15-mer single strand DNA.1 The probe is protected from DNAse and other biofouling species by encapsulation within the porous liposomes composed of mixed phospholipids, allowing direct application of the aptamer in biological fluids containing DNAse and other biofouling materials. The encapsulated sensor was directly tested in urine samples at physiological pH. We were able to detect below 100 ppb (500 nM) Hg2+ in urine (urine mercury threshold set by Biologischer Arbeitstoff Toleranz Wert or BAT)1 with no sample preparation other than pH adjustment. These results suggest that porous phospholipid nanoshells (PPNs) can serve as a general-purpose protection scaffold for biological sensing.