http://bura.brunel.ac.uk/handle/2438/273 2013-01-24T00:28:05Z 2013-01-24T00:28:05Z Ahmad, Abid Rafiq http://bura.brunel.ac.uk/handle/2438/7130 2013-01-18T09:26:46Z 1994-01-01T00:00:00Z

Title: Studies of novel diazanaphthoquinones and ion-responsive fluorescent quinoxaline derivatives Authors: Ahmad, Abid Rafiq Abstract: The work reported is divided into two parts: fIrstly a section dealing with the preparation of some novel diazanaphthoquinones and their reactions, especially the Diels-Alder reaction, and secondly an account of some quinoxaline derivatives and their fluorescence properties. Quinoxaline quinones containing electron-donating groups at both the 2- and 3- position have shown a difference in their stability and their behaviour in the Diels-Alder reaction compared to the stability and the reactions of quinoxaline quinone. Symmetrical dienes in the Diels-Alder reaction yielded the initial addition products, which were resistant to oxidation, whereas unsymmetrical dienes produced fully aromatized products. Crown ether derivatives of 5,8-dimethoxyquinoxaline and the corresponding quinoxaline quinones were prepared. An improved method for the preparation of a fluorescent derivatising reagent is described. This compound was then used to prepare ion-responsive fluoroionophores containing monoazacrown ethers of different cavity sizes. The complexation of these fluoroionophores, in dichloromethane, was achieved by using perchlorates of alkali and alkaline earth metals. A strong correlation between the size of the metal ion and the cavity size of the crown ether was seen in the fluorescence quantum yields of the complex, and a fluoroionophore containing a diazacrown ether gave particularly noteworthy results. A bathochromic shift with a strong hyperchromic effect was the most important feature caused by complexation with metal ions for these fluoroionophores. Fluorescent open chain ethers (podands) were also prepared and their complexation with metal ions was studied. A strong bathochromic shift and a hypochromic effect was observed especially in their excitation spectra. A further novel fluorescent derivatising reagent was prepared by extending the conjugated system. This gave the expected improved results upon the preparation of the derivatives including fluoroionophores having crown ethers of different cavity sizes. However, the changes in fluorescence did not correlate with the relationship between the sizes of the metals ion and the cavity of the crown ether. Nevertheless, a large bathochromic shift was observed on complexation with metal ions. Description: This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.

1994-01-01T00:00:00Z Hussain, Zaib-un-nisa http://bura.brunel.ac.uk/handle/2438/7122 2013-01-18T09:19:33Z 1999-01-01T00:00:00Z

Title: Metal recycle and recovery Authors: Hussain, Zaib-un-nisa Abstract: The development of techniques for the removal and recovery of metals from industrial effluent taking account of the consequences of the definition of waste in the Basel Convention on transfrontier shipment of waste is reported. The use of fluidised bed cell electrolysis in the recovery of metals from dilute solutions is investigated, and the conditions for recovery optimised. For the first time the application of a novel activated carbon cloth concentrator cell to recover metals from effluent solutions is reported and the conditions for its use optimised. Comparative studies using conventional mesh and plate electrodes, and novel activated carbon cloth electrode for the recovery of cobalt from dilute solution, and copper from three different hydrometallurgical solutions viz (i) Cu/Zn, (ii)Cu/Zn/Fe and (iii) Cu/Zn/Cd containing effluents were carried out. Application of concentrator cell technology including activated carbon cloth and ion exchange resin to the recovery of metals, including precious group metals, from industrial as-supplied samples is reported. Optimisation leads to successful recovery of iridium and palladium from very dilute solutions. The alternative recovery of metal as added-value chemicals is also investigated. The Basel Convention is concerned with transfrontier shipment of waste from developed to developing countries and has produced a need to investigate the leachability of metals in various forms. In this work the leachability of copper and zinc is studied under various conditions that model environmental situations and the results have been used to develop a methodology to determine whether a metal containing material would be subject to a shipment ban under the Convention. As part of the development of the methodology, leaching studies were also carried out on single chemical compounds of copper, zinc, cadmium and lead, and their bioavailability determined. Description: This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.

1999-01-01T00:00:00Z Marchese, S Silva, E http://bura.brunel.ac.uk/handle/2438/7009 2012-11-23T09:49:12Z 2012-01-01T00:00:00Z

Title: Disruption of 3D MCF-12A breast cell cultures by estrogens - An in vitro model for ER-mediated changes indicative of hormonal carcinogenesis Authors: Marchese, S; Silva, E Abstract: Introduction: Estrogens regulate the proliferation of normal and neoplastic breast epithelium. Although the intracellular mechanisms of estrogens in the breast are largely understood, little is known about how they induce changes in the structure of the mammary epithelium, which are characteristic of breast cancer. In vitro three dimensional (3D) cultures of immortalised breast epithelial cells recapitulate features of the breast epithelium in vivo, including formation of growth arrested acini with hollow lumen and basement membrane. This model can also reproduce features of malignant transformation and breast cancer, such as increased cellular proliferation and filling of the lumen. However, a system where a connection between estrogen receptor (ER) activation and disruption of acini formation can be studied to elucidate the role of estrogens is still missing. Methods/Principal Findings: We describe an in vitro 3D model for breast glandular structure development, using breast epithelial MCF-12A cells cultured in a reconstituted basement membrane matrix. These cells are estrogen receptor (ER)α, ERβ and G-protein coupled estrogen receptor 1 (GPER) competent, allowing the investigation of the effects of estrogens on mammary gland formation and disruption. Under normal conditions, MCF-12A cells formed organised acini, with deposition of basement membrane and hollow lumen. However, treatment with 17β-estradiol, and the exogenous estrogens bisphenol A and propylparaben resulted in deformed acini and filling of the acinar lumen. When these chemicals were combined with ER and GPER inhibitors (ICI 182,780 and G-15, respectively), the deformed acini recovered normal features, such as a spheroid shape, proliferative arrest and luminal clearing, suggesting a role for the ER and GPER in the estrogenic disruption of acinar formation. Conclusion: This new model offers the opportunity to better understand the role of the ER and GPER in the morphogenesis of breast glandular structure as well as the events implicated in breast cancer initiation and progression. Description: Copyright @ 2012 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and 85 reproduction in any medium, provided the original author and source are credited. The article was made available through the Brunel University Open Access Publishing Fund.

2012-01-01T00:00:00Z Haasmann, Stephan Otto http://bura.brunel.ac.uk/handle/2438/6961 2012-10-12T14:48:21Z 1998-01-01T00:00:00Z

Title: Analytical characterization of camel meat and milk fat Authors: Haasmann, Stephan Otto Abstract: The aim of this study was to characterize the fat composition of camel milk fat and camel hump fat and thereby assist in the technological development of camel milk and meat based products. The latter is of major interest in parts of Africa where the camel resides in large numbers. A combination of silver-ion and reversed phase HPLC enables the isolation of triglycerides according to their saturation class and carbon number. Subjection of the isolated triglycerides to enzymatic splitting with lipase and subsequent analysis of the free fatty acids generated enables a positional analysis of the main triglyceride components and thus a characterization of the fat. The analytical techniques employed may equally well be applied to other fats or oils to allow their characterization. Description: This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.

1998-01-01T00:00:00Z