<p><font face="Times New Roman"> <p align="left">The objective of this study was to determine the hydrosalinity fluxes associated with overland and subsurface (vadose zone) flow for different soils and land uses. For this purpose, the following data were collected during 2005 and 2006 in a typical small scale catchment located near the town of Riebeeck-Wes: weather data, hydrological and water quality measurements, soil water contents and chemistry, and vegetation growth. The area is characterized by a Mediterranean climate receiving winter rainfall of approximately 300 mm a <font face="Times New Roman">catchment is conservative, with Na</font> <font face="Times New Roman" size="1"><font face="Times New Roman" size="1">+ </font></font><font face="Times New Roman">and Cl</font><font face="Times New Roman" size="1"><font face="Times New Roman" size="1">- </font></font><font face="Times New Roman">being the dominant ions.</font></p> </font></p>

In this work, the modification of conducting substrates with thin (nanometer thick) aryl films via reaction with aryldiazonium salts was investigated. Two methods were used: modification by electro-reduction of the aryldiazonium salts and modification by spontaneous reaction of aryldiazonium the salts with the surface at open circuit potential. The majority of the studies were undertaken using p-nitrobenenze diazonium salt, which gives electro-active nitrophenyl (NP) films at the surface that can be detected and characterized by cyclic voltammetry. Films prepared spontaneously on carbon and gold electrodes at open circuit potential were characterized by electrochemistry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. At both carbon and gold, spontaneous modification proceeds via electron transfer from the surface to the diazonium salt.Furthermore, on both types of surface, spontaneously prepared NP films were found to be loosely packed multilayers of less than 5 nm in thickness. The spontaneous reaction was utilized for the patterning of carbon, gold, silicon and copper surfaces by microcontact printing (μCP) with diazonium salts. The presence of spontaneously formed films upon printing was confirmed by cyclic voltammetry and AFM. The films were demonstrated to be useful for the tethering of further molecules to the surface. Patterns prepared by μCP were imaged using scanning electron microscopy (SEM) and condensation figures. The preparation of two-component systems, with different chemical functionalities attached to different, well-defined, regions of the surface, was demonstrated. The optimization of the long term activity of glucose oxidase hydrogels by covalent attachment of the hydrogels to modified carbon electrodes was investigated. Covalent attachment was demonstrated, but the resulting electrode-hydrogel surfaces did not show long-term activities superior to those for physisorbed hydrogels. It is suggested that the limiting factor for long-term hydrogel activity is not adhesion of the hydrogel to the surface, but degradation of enzymatic activity by H2O2.

Most individuals are influenced by pain at some stage in their lives. It can either be of acute or chronic nature. An acute pain condition initiates and is treated within a time span of 12 weeks. Chronic pain can, however, take substantially longer to treat. Chronic pain may last up to 6 months after the original injury was sustained. The after effects of chronic pain can, however, take years to heal, but physical and emotional scars may even last much longer than the initial chronic ailment. In this study the skin was chosen as an area for delivery of non-steroidal anti-inflammatory drugs for the treatment of pain at the joint and muscle tissue regions. The stratum corneum (the topmost horny layer of the skin), however bars the effective movement of chemical substances across the skin as it forms part of the skin's function to protect the superficial tissue of the body against the external environment. It furthermore plays an important role in regulation of the movement of chemicals across the skin. Sweat pores and hair follicles can be utilised as pathways for the movement of chemical substances through the stratum corneum. Physical deformation ie, hydration of the top layer of the skin, may also enhance the movement of chemicals The non-steroidal anti-inflammatory drug, diclofenac, has been evaluated for transdermal diffusion. Three different diclofenac salts were evaluated, namely diclofenac diethylamine, diclofenac hydroxyethyl pyrrolidine and diclofenac sodium. These salts have the potential to relieve systemic pain conditions. Diclofenac salts, however, possess physicochemical characteristics that are unfavourable for transdermal diffusion. Pheroid™ delivery technology, as patented by the Northwest-University, was implemented as a method to enhance transdermal delivery of the diclofenac salts. During the study each of the diclofenac salts was formulated in a Pheroid™ and non-Pheroid™ formulation. All the formulations as well as corresponding retail products containing similar diclofenac salts were evaluated in order to determine which preparation had the most effective transdermal diffusion. High performance liquid chromatograhphy was implemented in order to determine the concentration of each salt in their various preparations. The Pheroid™ and non-Pheroid™ formulations were also compared to retail products currently available. An active ingredient flux was determined by means of Franz cell diffusion studies. Membrane diffusion studies were utilised in order to determine whether the active ingredients were effectively released from the formulated preparations and market products. Membrane diffusion studies determined that Arthruderm (the retail product containing diclofenac sodium) had the most potential to effectively release the active ingredient from the formulation (median flux 28.36 ± 0.26 ug/cm2.h"1). Franz cell diffusion studies showed no flux values for any of the evaluated preparations, including the retail products. Concentrations obtained within the epidermis and dermis were determined through tape stripping of these areas. The largest concentration of active ingredient within the epidermis was obtained from the studies done on Voltaren® (the retail product containing diclofenac diethylamine) which was 7.27 |ig/cm2.h"1 the largest value in the dermis was obtained from a non-Pheroid™ formulation containing diclofenac sodium (4.47 ug/ml). Confocal laser scanning microscopy was utilised and the micrographs where evaluated to ensure that the diclofenac salts were effectively entrapped in the Pheroid™ delivery system. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

Most individuals are influenced by pain at some stage in their lives. It can either be of acute or chronic nature. An acute pain condition initiates and is treated within a time span of 12 weeks. Chronic pain can, however, take substantially longer to treat. Chronic pain may last up to 6 months after the original injury was sustained. The after effects of chronic pain can, however, take years to heal, but physical and emotional scars may even last much longer than the initial chronic ailment. In this study the skin was chosen as an area for delivery of non-steroidal anti-inflammatory drugs for the treatment of pain at the joint and muscle tissue regions. The stratum corneum (the topmost horny layer of the skin), however bars the effective movement of chemical substances across the skin as it forms part of the skin's function to protect the superficial tissue of the body against the external environment. It furthermore plays an important role in regulation of the movement of chemicals across the skin. Sweat pores and hair follicles can be utilised as pathways for the movement of chemical substances through the stratum corneum. Physical deformation ie, hydration of the top layer of the skin, may also enhance the movement of chemicals The non-steroidal anti-inflammatory drug, diclofenac, has been evaluated for transdermal diffusion. Three different diclofenac salts were evaluated, namely diclofenac diethylamine, diclofenac hydroxyethyl pyrrolidine and diclofenac sodium. These salts have the potential to relieve systemic pain conditions. Diclofenac salts, however, possess physicochemical characteristics that are unfavourable for transdermal diffusion. Pheroid™ delivery technology, as patented by the Northwest-University, was implemented as a method to enhance transdermal delivery of the diclofenac salts. During the study each of the diclofenac salts was formulated in a Pheroid™ and non-Pheroid™ formulation. All the formulations as well as corresponding retail products containing similar diclofenac salts were evaluated in order to determine which preparation had the most effective transdermal diffusion. High performance liquid chromatograhphy was implemented in order to determine the concentration of each salt in their various preparations. The Pheroid™ and non-Pheroid™ formulations were also compared to retail products currently available. An active ingredient flux was determined by means of Franz cell diffusion studies. Membrane diffusion studies were utilised in order to determine whether the active ingredients were effectively released from the formulated preparations and market products. Membrane diffusion studies determined that Arthruderm (the retail product containing diclofenac sodium) had the most potential to effectively release the active ingredient from the formulation (median flux 28.36 ± 0.26 ug/cm2.h"1). Franz cell diffusion studies showed no flux values for any of the evaluated preparations, including the retail products. Concentrations obtained within the epidermis and dermis were determined through tape stripping of these areas. The largest concentration of active ingredient within the epidermis was obtained from the studies done on Voltaren® (the retail product containing diclofenac diethylamine) which was 7.27 |ig/cm2.h"1 the largest value in the dermis was obtained from a non-Pheroid™ formulation containing diclofenac sodium (4.47 ug/ml). Confocal laser scanning microscopy was utilised and the micrographs where evaluated to ensure that the diclofenac salts were effectively entrapped in the Pheroid™ delivery system. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

Effective management of saline soils requires rapid, reliable methods of monitoring both soil water content (theta) and salt concentration, the latter measured in terms of electrical conductivity (sigma). This thesis examines estimation of theta, and bulk soil sigma (sigmaa) and soil water sigma (sigmaw), using time domain reflectometry (TDR). Calibration experiments were conducted in soil columns and in a vineyard that were irrigated with saline water. Within a theta range of 0.025--0.490 m3/m3, the correlation between TDR theta (thetaTDR) and gravimetrically determined theta (theta g) was high (r2 = 0.979 in soil columns, r2 = 0.836 in the field). The error of estimate of thetaTDR was 0.020 m3/m3 or less. Field thetaTDR estimates were sensitive to high salinity (sigmaw > 10 dS/m). Using a dual pathway parallel conductance (DPPC) model, sigma a was derived from sigmaw of saturated paste extracts and theta g. The correlation of TDR sigmaa to DPPC sigmaa was good in the laboratory (r2 = 0.915), and moderate in the field (r2 = 0.791), indicating a functional relationship between sigmaw and theta and TDR sigmaa. Models, to estimate sigmaw, were built by regression between paste extract sigma w and TDR sigmaa and thetaTDR. In a sigma w range of 3.0--23.4 dS/m in the columns, error of estimate of sigma w was small at 1.50 dS/m (+/-12.4% relative error range). In a sigma w range of 2.2--25.2 dS/m in the field, error of estimate of sigma w was 3.37 dS/m (+/-37% relative error range), which was significantly higher than the acceptable error range of +/-10%. ANOVA tests indicated that both TDR sigmaa and sigmaw&middot;theta changed significantly with respect to the same sources of variance. Error in field estimates of sigmaw was associated with effects of salinity on thetaTDR and variability of soil conditions, particularly with respect to depth and time of sampling.

The focus of this work is to synthesize and immobilize novel rigid tetraphosphine linkers via the formation of phosphonium groups and by direct adsorption of tetraphosphine salts on oxide surfaces. These methods offer the possibility to study the mechanism of the phosphonium formation in more detail by utilizing solid-state NMR spectroscopy. It has also been a point of interest to study the linkers and catalysts under realistic conditions, in the presence of solvents. Therefore, HRMAS (high-resolution magic angle spinning) NMR spectra of several phosphonium salts, adsorbed on SiO2, have been studied. This technique allows one to probe the leaching and mobility of the linkers on the surface. The mobilities of the linkers and the catalysts are crucial factors for the performance and design of the immobilized catalysts. Finally, since the exact mode of binding to the surface is unknown and is being discussed in the literature, for example, as hydrogen bonding between the F atoms in BF4- and surface silanol protons, the influence of the counteranion on the binding of phosphonium salts on silica surfaces is of utmost interest. For surface mobility studies a monolayer of phosphonium salts on the silica surface, both without solvent and in the presence of solvent, has been studied via 31P and 2H CP/MAS and HRMAS. Our findings show that the integrity of the tetraphosphine scaffold linkers is based upon how it is immobilized. The best system is formed when the phosphine is immobilized on the SiO2 support by adding Cl(CH2)3Si(OEt)3 to the reaction mixture. In this way, phosphonium salts are obtained, which are bound to the surface irreversibly by electrostatic interactions, as proven by solid-state NMR. In addition, leaching and mobility studies prove that the solvents play a crucial role, and the more polar solvents, such as DMSO, lead to the most extensive leaching due to the solvents' strong adsorption on the SiO2 surface. Leaching studies also show that the counteranion has an influence on the binding of the phosphoniumn salts on the SiO2 surface. The leaching proceeds in the following manner: BF4- > I- > Br- > Cl-. This is an indication that there is an additional interaction between the anion and, most probably, the surface silanol protons.

[Formulae and special characters can only be approximated here. Please see the pdf version of the abstract for an accurate reproduction.] Group 15 Lewis base adducts of Group 11 coinage metal salts of the form MX : L (1:n), where M=Cu(I),Ag(I),Au(I); X=(pseudo-)halide (Cl,Br,I,SCN,CN) and oxyanion; L-uni- or bi-dentate pnicogen ligand and n=1-4, may adopt monomeric, dimeric, oligomeric or polymeric structural forms. For the purpose of this study, the pnicogen bases are divided into two groups: the 'harder' nitrogen base ligands and 'softer' phosphine/arsine/stibine ligands. A sizeable body of structural data exits for adducts of silver(I) salts. Those with uni-dentate nitrogen base ligands are usually restricted to readily accessible liquid bases such as pyridine and its derivatives. The extension of such series to encompass ligands with more varied base characteristics may assist in the access of new bonding modes and stereochemistry, leading to control of these and of stoichiometry. Herein a number of complexes of copper(I) salts with uni-dentate nitrogen and bi-dentate phosphine/arsine/stibine adducts with differing degrees of complexity have been characterized, extending the known range of structural forms. Systematic variations in stoichiometry, halide, ligand and solvent of crystallization have provided a range of complexes whose structures have been determined by single crystal X-ray diffraction techniques. The structural relationship between these and other known adducts, often including their silver analogues, are considered, permitting comparisons of various common features and differences. The first section of this thesis (Chapter 3 and Chapter 4) reports a number of complexes of the form CuX : L (1:n) (CuX)Ln, L=uni-dentate nitrogen base ligand with n=1-3, the second section (Chapter 5 through Chapter 10) reports adducts with bi-dentate bis(diphenylpnicogeno)alkane ligands, Ph2E(CH2)xEPh2 (whereE=P,AS,Sb and x=1-6). The structural types and copper(I) coordination environments are influenced by CuX (salt) : ligand stoichiometry, the stereochemistry and basicity of the ligand, the type and size of the counter-ion (where applicable) and crystallization solvent. The structural types found for copper(I) (pseudo-)halide and oxyanion species are similar to those found for their silver(I) analogues, although the transitions between structural types may occur with different pnicogen and halide atoms, consequent on the smaller size of the copper(I) ion and differences in stereochemical preferences.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Feb. 7, 2008). Includes bibliographical references (p. 114-133).

Thesis (Ph. D.)--University of Adelaide, Dept. of Soil Science, 1996. / Copies of author's previously published articles in pocket inside back cover. Includes bibliographical references (leaves 147-160).

Thesis (Ph. D.)--University of Wyoming, 2006. / Title from PDF title page (viewed on April 11, 2008). Includes bibliographical references.