Risk factors for prostate cancer : a case-control study investigating selected key exposures and their interactions with predisposition genes

Prostate cancer is the UK number one male cancer. Evidence from epidemiological studies suggests only age, race and family history as established risk factors. Other factors such as low dose diagnostic radiations and surrogate hormone markers such as baldness, finger length pattern and acne are hypothesized to have a potential role in the aetiology of prostate cancer. It is evident that genetics plays an important role in prostate cancer aetiology. This thesis focuses both environmental and genetic factors. The environmental factors include selected surrogate hormone markers, medical diagnostic radiation procedures and family history of prostate cancer. The genetic part explores genetic polymorphisms that could have implications for interactions with exposures studied. Single nucleotide polymorphisms (SNPs) involved in mechanistic pathways related to DNA repair genes and potential hormone marker genes were the main targets.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The Metalorganic Vapour Phase Epitaxy Growth of A^{III}B^{V} Heterostructures Observed by Reflection Anisotropy Spectroscopy

Reflectance anisotropy spectroscopy is a useful technique used for in situ observation of the metalorganic vapour phase epitaxy growth, because it does not require vacuum in the reaction chamber. With this method we are able to observe the quantum dot growth, the incorporation of indium or antimony atoms in the layer or the monolayer growth of GaAs. We can also estimate the amount of InAs needed for the quantum dot formation, the time necessary for the quantum dot growth or reveal the unintended growth of InAs quantum dots from large dissolved InAs objects

Improvement of luminescence properties of n-GaN using TEGa precursor

The aim of this work is to compare and improve optical and structural properties of GaN layers prepared using TMGa or TEGa precursors. MOVPE grown GaN buffer layers on sapphire substrates are usually grown from TMGa precursor at the temperatures above 1000 degrees C. These layers contain deep and shallow acceptor levels which are responsible for blue and yellow defect bands in luminescent spectra. Both defect bands are detrimental for all major nitride device applications. Especially n-doped GaN layers suffer from strong yellow defect bands. In this work, it is shown that yellow band photoluminescence intensity can be suppressed by using TEGa precursor during the growth of n-doped GaN layers. Different kinds of growth parameters, such as growth temperature or growth rate, have been studied. It is also shown that the change of carrier gas (H-2 or N-2) has very strong influence on the layer quality. H-2 carrier gas increased intensity of yellow band in sample grown from TEGa precursor while N-2 carrier gas had the same effect for sample grown from TMGa precursor. Variable energy positron annihilation spectroscopy showed creation of single V-Ga in H-2 atmosphere and clustering of V-Ga to big complexes ((V-Ga)(3)(V-N)(n)) in N-2 atmosphere

Wavelength Effect on Photocatalytic Reduction of CO2 by Ag/TiO2 Catalyst

Photocatalytic reduction of CO2 by water was performed in the presence of a Ag/TiO2 catalyst under illumination by lamps with different wavelengths (254, 365, and 400 nm). The yields of the main products (methane and methanol) were higher with the 254 nm lamp than with the 365 lamp while no products were observed with the 400 nm lamp. This was because the electron-hole generation rate increased with increasing energy of irradiation (decreasing wavelength) and there were higher densities of electron states at higher energies in TiO2. The increased efficiency of electron-hole generation with a shorter wavelength irradiation increased the efficiency of the catalyst. The energy of the electrons excited by visible light (400 nm) was too low for CO2 photocatalytic reduction.Web of Science32581581