The effects of gold sodium thiomalate (GST) on murine spleen cells were investigated using in vitro mitogen blastogenesis techniques. Addition of GST to intact spleen cells resulted in a decreased blastogenic response to the T cell mitogen, concanavalin A (Con A). Thymidine uptake of spleen cells depleted of macrophages and cultured with Con A and GST demonstrated biphasic effects. At 2.5 pg Con A/ml, blastogenesis of macrophage depleted spleen cells was inhibited to a lesser degree than intact spleen cells; whereas, at 0.5 pg Con A/ml, the macrophage depleted spleen cells were inhibited to a greater degree than the intact spleen cells. Addition of GST at intervals ranging from 0 to 48 hours indicated that inhibition occurred within 36 hours following mitogen stimulation. These results suggest that GST inhibits early events of lymphocyte activation by direct interaction with lymphocytes.

The Björkdal gold deposit is located in the eastern part of the Skellefte district, northern Sweden. Twenty thin sections from four production areas in the open pit and four drifts from the underground mine were analysed for mineral association and grain size distribution of gold. In addition, the texture of gold was investigated in order to find out how that affects the recovery of gold. The overall gold grain size distribution shows an interval from very fine-grained (2 μm) to coarse grained(856 μm) while the overall median size is 7 μm. Gold from the Quartz Mountain production area displays the smallest median size of 4 μm, whereas gold from the sampled drifts at 340m- and 385m- level has the largest median size of 14 μm. Gold at grain boundary is the dominant textural mode of gold from all sampled locations and varies from 62% to 92%. This is followed by intergrown which ranges between 8% and 29%. Of the sulfides, pyrite, chalcopyrite and pyrrhotite are the most common. Galena and was also present in the samples. Gold is significantly and positively correlated with tellurium (Appendix 10.1.1), and weakly positive correlated to silver and mercury. Gold show a close association to bismuth-tellurides in the samples. Apart from native gold, which is the dominant mineral phase of gold, two additional gold-bearing tellurium minerals were detected with SEM-EDS, a Au-Te-mineral and a Ag-Au-Te-mineral. One additional bismuth-telluride mineral aside from the most commonly occurring tsumoite (BiTe) was also detected with SEM, with a elemental composition of Bi-Te-S. Liberated gold in the tailings was optically identified in two thick sections, TB1-02feb-1 and TB1-07feb-1 (Fig. 32A and B), where the flotation circuit failed to float the free gold. One grain of gold was also identified intergrown with bismuth-telluride as an inclusion in silicate (Fig. 33), where the flotation properties of the larger silicate grain likely dominated in the flotation process. This thesis highlights the importance of further quantitative analysis utilizing SEM/QEMSCAN/MLA to retrieve representative mineralogical data to benefit the mineral processing of the ore from the active mine. Keywords: Björkdal gold deposit, gold, gold-telluride, SEM, mineral association, grain size,geometallurgy.

This dissertation focuses on the development, characterization, and analysis of luminescent materials and coatings for sensing applications, including CO2, heavy metals, and silver. Chapter 2 involves the use of a gold(I) pyrazolate trimer that is able to detect silver ions with an AgNP medium. Detection of silver is vital, because there is an influx of silver into our environment caused by the increased use of AgNP. Therefore, having a sensor that is able to differentiate between and detect only Ag ions is an important first step to solving the toxicity mystery of AgNPs. Chapter 3 focuses on the development of sensor coatings containing a Eu(III) based luminescent system for sensing dissolved CO2 without the aid of an absorption-based dye. It is well-known that monitoring CO2 levels in our environment is important since even at low concentrations it can cause adverse health effects to the human body. This work demonstrates a pH-sensitive Eu complex being used directly as a CO2 sensor without the aid of any other absorption-based dye. Chapter 4 explores the idea of developing a heavy metal sensor for lead and its ability to detect lead in wide concentration range upon changing the pH of the medium and the polymer matrix. Different heavy metals have toxicity at different concentrations, therefore, being able to change the dynamic range of the sensor is advantageous. This research is the first step towards developing a luminescent Pb sensor with a tunable dynamic range.

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Preface: For anyone standing on the ridge of the Witwatersrand on a spring day in September 1886 the sight immediately to the south represented a hive of activity and hope. Nearly a hundred years later ample evidence stretches away on both sides of the watershed to confirm the fulfilment of those early sentiments. It is, nevertheless, all too easy to ignore the struggles and failures which marked the beginnings of the world's greatest gold field in the light of its subsequent abundant success. Only when attention is turned to the individual companies formed to exploit the discovery does the true picture emerge of the lack of adequate technological and managerial knowledge amongst the early pioneers and of the financial frailty of their companies. The object of this thesis is to shed light on these beginnings by reviewing the histories of four of the earliest companies established to work the main reef. The approach adopted is to scrutinize the material available with a view to determining the motivations and actions of the managements of the various companies with regard to their economic environment, whether within or without the individual company. Clearly, the availability of information is a major determinant of the success of any such venture and this was particularly so in the case of the companies considered. With the exception of the Barlow Rand Limited holding of the H. Eckstein and Company Archives, which offers an integral coverage of that firm's dealings with the emerging industry, and which is certainly the most comprehensive source of information available to the researcher, little material relating to specific gold mining companies has survived. Under these circumstances it was necessary to rely heavily for information on the local press. These newspapers proved an invaluable source in this regard. As a mining camp with a limited capacity for generating newsworthy incidents, the newspapers of early Johannesburg found an eager readership for information about the industry which lay at the heart of the community. For their part, the managements of the various mining companies found in the pages of the local press an outlet for intelligence both true and false; the press was a useful vehicle for the publication of directors' and annual reports to meet a wider audience, but similarly it could be and was used to disseminate 'spectacular' reports calculated to influence the status of a company's stock on the local share market. As a research source the press has thus to be approached with caution but its value, if the warning is heeded, is in no way diminished. Beyond these two sources the next most valuable accumulation of data on the early industry is "The Gold Fields Collection" housed in the Cory Library for Historical Research at Rhodes University. As a collection it is far from complete and it is to be hoped that the donors will in future see fit to augment it with further material as this becomes available. It neverthess proved an invaluable source for the investigation of at least one of the companies of the study and for a general background to the industry.

Gold nanoparticles (GNP) have been widely used as optical imaging and photothermal therapy agents due to their biocompatibility, simplicity of conjugation chemistry, optical tunability and efficient light conversion to heat. A number of in vitro and in vivo studies have demonstrated that they can be used as effective thermal therapy and imaging contrast agents to treat and diagnose cancer. As clinical applications of GNPs for cancer imaging and therapy have gained interest, efforts for understanding their accumulation kinetics has become more important. Given the recent demonstration of intrinsic two-photon induced photoluminescence (TPIP) of gold nanoshells (GNSs) and gold nanorods (GNRs), TPIP imaging is an efficient tool for investigating the microscopic distribution of the GNPs at intra-organ level. The following work explores these GNPs’ physical and optical properties for effective use of GNPs in TPIP imaging and examines the feasibility of using intrinsic TPIP imaging to investigate GNP’s biodistribution in bulk tumors and thin tissue slices processed for standard histology. Our results showed that GNPs yield a strong TPIP signal, and we found that the direct luminescence-based contrast imaging of GNPs can image both GNPs and nuclei, cytoplasm or vasculature simultaneously. Also, we present the effect of GNP morphology on their distribution within organs. Collected images showed that GNPs had a heterogeneous distribution with higher accumulation at the tumor periphery. However, GNRs had deeper penetration into tumor than GNRs due to their shape and size. In addition, GNPs were observed in unique patterns close to vasculature. Finally, we introduce single- and multiple-dose administrations of GNPs as a way of increasing GNP accumulation in tumor. Our results show that multiple dosing can increase GNP accumulation in tumor 1.6 to 2 times more than single dosing. Histological analysis also demonstrated that there were no signs of acute toxicity in tumor, liver and spleen excised from the mice receiving 1 injection, 5 injections of GNPs and trehalose injection. / text

M.Com. (Economics) / The objective of the thesis was to examine the relationship between the grade of ore, physical electricity consumption and working cost in the South African gold mining industry for the period 1965 - 1982. The South African economy is heavily dependent on the gold mining industry, which is a major earner of foreign exchange and a large consumer of labour and agricultural and industrial output. The industry is also important as a source of finance for both the private sector and the Treasury. Curtailment of activity within the industry by closing down the more marginal mines or by shortening the life of the industry' as a whole because of rising costs and/or a hesitant gold price, will harm the South African economy in a number of ways. The industry has no option but to regard the gold price as given. The remaining ore reserves tend to be of a lower grade and/or to be found at greater depth. Controlling the working costs would seem to be almost the only option open to the industry.

There are numerous histories of the Victorian goldfields, individual digger�s experiences, and the digging community as a whole. By contrast, very little has been written about the early gold mining companies. This thesis seeks to address this dearth in part, with a longitudinal study of one of the leading gold mining companies in nineteenth-century Victoria. The Port Phillip and Colonial Gold Mining Company (�Port Phillip Company�) was one of many �gold bubble� companies formed in England during 1851-3 to undertake gold mining in Australia. Within a few years it was the only survivor of this episode of British corporate gold-fever. The thesis argues that the influence of Rivett Henry Bland, the company�s managing director, was instrumental in its success, particularly in its early years when faced with anti-company sentiment and unfavourable mining legislation. The company established a large-scale operation at Clunes in 1857, rapidly assuming a pre-eminent position in colonial gold mining with its superior technology and mining practices. Historians generally portray Australian gold mining operations as small, locally funded and inefficient, prior to British capital investment in the late 1880s. While true of the larger picture, this simply emphasises the uniqueness of the British-owned and funded Port Phillip Company, the largest and most efficient gold mining operation in Australia from 1857 until the early 1880s. The company and its investment offshoot, the Victoria (London) Mining Company, invested in over thirty Victorian gold mining companies during the 1860s. Again, this runs counter to the general view that British investment in Australian gold mining began only in the late 1880s. Although the two companies� investments equalled only a fraction of the later wave of British capital in absolute monetary terms, their contribution to the growth of the Victorian gold mining industry at the time was significant.

Gold nanoparticle has emerged as an attractive platform for drug delivery applications by complementing the existing drug delivery carriers. Currently, only a few gold nanoparticle-based anticancer drug delivery systems have been reported, compared to the polymer-based delivery systems. Additionally, there is still a lack of understanding for the behavior and fate of the gold-drug conjugate in the body that further attention is required. The overall goal of this thesis is to investigate the in vivo behavior of colloidal gold nanoparticle and its therapeutic efficacy in an animal model, especially in a drug delivery application. To achieve this goal, we investigated the feasibility of using colloidal gold nanoparticle as an anticancer agent delivery vehicle for treatment of cancer. Then, long-term clearance, toxicity, and biodistribution of colloidal gold nanoparticle were studied to further aid in understanding of using colloidal gold nanoparticle as a drug delivery platform. In particular, two representative sizes of gold nanoparticles, 5nm and 60nm, were investigated for the size effect on the therapeutic efficacy, toxicity, biodistribution, and clearance in cancer nanotherapy. We believe that nanoparticle size plays a critical role in not only delivering the drug to the target site but also determining the in vivo behavior such as biodistribution and clearance. By choosing an appropriate size scale for the system, we successfully used the small-sized gold nanoparticles for drug delivery applications, which also displayed no apparent toxicity with desirable clearance from the biological system. This work is significant by providing an insight on a potential ideal candidate for drug delivery carrier for cancer nanotherapy.

There are numerous histories of the Victorian goldfields, individual digger�s experiences, and the digging community as a whole. By contrast, very little has been written about the early gold mining companies. This thesis seeks to address this dearth in part, with a longitudinal study of one of the leading gold mining companies in nineteenth-century Victoria. The Port Phillip and Colonial Gold Mining Company (�Port Phillip Company�) was one of many �gold bubble� companies formed in England during 1851-3 to undertake gold mining in Australia. Within a few years it was the only survivor of this episode of British corporate gold-fever. The thesis argues that the influence of Rivett Henry Bland, the company�s managing director, was instrumental in its success, particularly in its early years when faced with anti-company sentiment and unfavourable mining legislation. The company established a large-scale operation at Clunes in 1857, rapidly assuming a pre-eminent position in colonial gold mining with its superior technology and mining practices. Historians generally portray Australian gold mining operations as small, locally funded and inefficient, prior to British capital investment in the late 1880s. While true of the larger picture, this simply emphasises the uniqueness of the British-owned and funded Port Phillip Company, the largest and most efficient gold mining operation in Australia from 1857 until the early 1880s. The company and its investment offshoot, the Victoria (London) Mining Company, invested in over thirty Victorian gold mining companies during the 1860s. Again, this runs counter to the general view that British investment in Australian gold mining began only in the late 1880s. Although the two companies� investments equalled only a fraction of the later wave of British capital in absolute monetary terms, their contribution to the growth of the Victorian gold mining industry at the time was significant.