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<p>In this study we report on the effect of the deposition parameters on the morphology and structural properties of CNTs, synthesized by means of the hot-wire chemical vapour deposition technique. SEM, Raman and XRD results show that the optimum deposition conditions for the HWCVD synthesis of aligned MWCNTs, with diameters between 50 and 150 nm and lengths in the micrometer range are: Furnace temperature of 500 &ordm / C, deposition pressure between 150 and 200 Torr, methane/hydrogen dilution of 0.67 and a substrateto- filament distance of 10 cm.</p>

The techniques of x-ray diffraction of liquids are employed to study the salt TlCo(CO)4 in two solvents, tetrahydrofuran and dimethylsulfoxide. Radial distribution functions calculated from scattering data are analyzed in terms of the structure of these solutions, and the results are compared to those of other studies of the same and similar solutions investigated by infrared techniques. In tetrahydrofuran, a solvent of low dielectric constant, the evidence indicates close association of anion and cation, and contact ion pair and covalent models are presented and discussed. In dimethylsulfoxide, a solvent of high dielectric constant, the evidence indicates relatively loose association or no association of anion and cation, and solvent-separated ion pair and free ion models are presented and discussed.

Gas-phase electron diffraction (GED) is the method of choice for determining the structures of molecules containing between two and 100 atoms, free from intermolecular interaction. However, for many molecules it becomes necessary to augment the experimental GED data with information from other sources. The SARACEN method, used routinely at Edinburgh when determining structures, allows computed parameters from ab initio and density functional theory (DFT) calculations to be used as extra data in the GED refinement process. This thesis describes the determinations of the gas-phase structures of molecules that contain heavy p-block elements, including examples from Groups 13, 14, 15 and 16. Each of the compounds studied was solid at room temperature, requiring heating to produce a suitable vapour pressure and vaporisation rate and testing the existing electron diffraction apparatus to its limits. Use was made of a new heated reservoir, recently developed in Edinburgh by a previous PhD student, which has allowed compounds to be studied that were previously inaccessible. The molecules that were studied during the course of this degree are: In(P3C2But2), In(P2C3But3), Sn(P2C2But2), Sb2(C6F6)3, Bi2(C6F6)3, Se(SCH3)2 and Te(SCH3)2. While determining the structures of these molecules, accurate theoretical geometries have been obtained using both ab initio and DFT methods. As a result a better understanding has been achieved of which methods are suitable for use in calculating the structures of molecules with heavy p-block elements. The use of pseudopotentials as opposed to all-electron basis sets proved necessary when performing calculations on such large molecules with heavy atoms. The extent to which these pseudopotentials, especially ones that consider very few electrons to be in the valence shell of an atom, can affect the calculated geometries has been shown to be considerable. In addition, methods being developed to compute vibrational corrections for gas-phase structure determination have been extended to the crystalline phase. Molecular dynamics simulations have been used to derive the effects of vibrations on average nuclear positions, relative to equilibrium positions. The differences, when applied to coordinates obtained experimentally by neutron diffraction yield experimental equilibrium structures.

The effect of temperature on the crystal structure of deuterated piperidine has been studied using neutron powder diffraction. Differential scanning calorimetry indicates that there are multiple phases accessible via changes in temperature however there is no evidence of this in the neutron powder diffraction study with only one phase observed in the range 2 – 250 K and under various crystallisation conditions. The effect of pressure up to 2.79 GPa has also been determined. The compression of the structure is facilitated through the closing up of voids in the structure and no phase transition is observed. Differential scanning calorimetry has shown N-methyl and N,N-dimethylformamide both exhibit a thermal event prior to melting. Low temperature neutron powder diffraction has shown these transitions are associated with the onset of methyl group rotation. Neutron powder diffraction studies show formamide exhibits remarkable polymorphism at ambient temperature and pressures between 0.1 GPa and 3.6 GPa, forming four new polymorphs. All the structures consist of N-H…O hydrogen bonded chains. The formation of the various polymorphs can be rationalised in terms of the orientation of the molecules within the hydrogen bonded chains and the resultant structures formed by further hydrogen bonds between the chains. This is in stark contrast to the effect of varying conditions of temperature where only one structure exists from 2 K right up to the melting point. The effect of temperature on the crystal structure of pyrazine in the range 8 – 315 K is described. At temperatures below 90 K the structure undergoes a phase transition to a previously uncharacterised phase, designated phase IV, which is closely related to the previously known phase I. The crystal structure of phase III has been determined at 315 K. The crystal structure of pyrazine has been determined at room temperature at pressures between 0.11 GPa and 9.36 GPa. At 0.94 GPa a transition from phase I to phase IV is observed. This is the same phase as observed at low temperatures. Crystal growth at 215 K results in the formation of two different phases of mesitylene; phase II and a new previously unknown phase designated phase IV. The structure of phase IV has been determined and found to be stable in the range 90 – 221 K. On cooling a crystal of deuterated mesitylene in phase II to 90 K a transition to phase III was observed and the resultant crystal structure is closely related to that of phase II.

Ce travail de thèse a pour objet une méthode de détermination du champ électromagnétique au voisinage des bâtiments urbains, ainsi que l’évaluation de l’incertitude associée, liée aux paramètres variables des façades. Cette étude met en oeuvre une méthode théorique, précise et rapide de caractérisation du champ électromagnétique réfléchi par des objets diffractants diélectriques de taille supérieure à quelques longueurs d’onde. La réflexion comprend la rétrodiffusion, la réflexion spéculaire et la réflexion non-spéculaire. La méthode se trouve dans la catégorie des techniques basées sur les courants équivalents et calcule le rayonnement de ces courants à l’aide des fonctions de Green associées à l’interface entre deux diélectriques semi-infinis. Les fonctions de Green tiennent compte de la présence de l’objet diffractant correctement dans toutes les directions, c’est pourquoi la méthode proposée ici présente une précision plus importante que les méthodes du même type, particulièrement dans les directions nonspéculaires. La méthode peut être appliquée dans différents domaines : radar, télédétection, géophysique, et plus particulièrement dans l’environnement urbain dans le cadre de cette thèse. Un modèle simple de bâtiment urbain, composé des murs (en béton) et des fenêtres (en verre), est adopté dans les exemples présentés au cours du manuscrit, avec l’avantage de tenir compte simplement du type et de l’épaisseur des fenêtres. La méthode des fonctions de Green étant rapide et peu exigeante en temps de calcul et en ressources informatiques, elle permet d’obtenir une caractérisation rapide du champ, et en conséquence de déterminer l’influence de plusieurs paramètres intervenant dans le calcul du champ au voisinage d’un bâtiment via des études paramétriques/statistiques. L’influence de la variation de plusieurs paramètres est approfondie par des études statistiques. Parmi ces paramètres citons : la permittivité du matériau principal de la façade, la distribution des fenêtres, les dimensions (la largeur et la hauteur) des fenêtres et le type du vitrage (l’épaisseur des fenêtres). La connaissance des paramètres influents et la quantification de leur influence sur le champ réfléchi permettront aux simulateurs de la propagation d’onde de faire des simplifications qui accélèrent le temps de calcul tout en maintenant une bonne précision des résultats. Ce travail pourra être utilisé afin d’obtenir des modèles de propagation plus précis / This study presents a theoretical, fast and accurate method for characterizing the electromagnetic fields reflected by dielectric objects larger than a few wavelengths. The method is based on equivalent currents whose radiation is calculated by the Green's functions associated with the interface between two semi-infinite dielectrics. The Green's functions take into account the presence of the diffracting object correctly in all directions ; the proposed method presents thus a greater accuracy than other methods of the same type. The method being not very demanding in computation time and computer resources, it makes possible to determine the influence of several parameters involved in calculating the field in the vicinity of a building through statistical studies. These studies will allow propagation simulators to make simplifications that speed up the computation time while maintaining good accuracy

TAT peptide is one of the best-characterised cell penetrating peptides (CPPs) derived from the transactivator of transcription protein from the human immunodeficiency virus 1 (HIV-1). TAT peptide is able to cross the cell membrane and deliver various biomolecules into cells with low immunogenicity and no toxicity. However, the exact mechanism of internalization still remains a subject of controversy. Lamellar neutron scattering was used to determine the location of TAT peptide in the negativelycharged phospholipids bilayers. The results reveal two locations, one in the peripheral aqueous phase between the adjacent bilayers and the second one below the glycerol backbone region of the lipid bilayer. A concentrationindependent membrane thinning above a peptide concentration threshold (1mol%) and a contiguous transbilayer water channel at the largest peptide concentration (10mol%) were also found. This evidence led to the suggestion that the toroidal pore model might be involved in the transmembrane mechanism at high peptide concentration. Another set of neutron diffraction experiments examined the interaction between the TAT peptide and neutral phospholipids showed that TAT peptide preferentially intercalated into the hydrophobic core and the glycerol backbone region of the neutral lipid bilayer at the lowest peptide concentration investigated (0.1mol%), indicating that the insertion did not require negatively-charged phospholipids. There was also clear evidence for the concentration-dependent reorientation of TAT peptide. A plasmid containing the human copper-zinc SOD gene linked with the coding sequence for a 11-aa HIV-TAT peptide (pGEX-TAT-SOD, 513bp) was constructed and used to express a recombinant fusion protein in Escherichia coli strain BL21 (DE3). High-level expression of TAT-SOD soluble protein with a GST tag (44-kDa) was achieved under optimal expression conditions and a small-scale glutathione affinity column or large-scale ion-exchange chromatography used for its purification. The potential protective effect of TAT-SOD against UV-induced cell damage was studied on UVC-irradiated MDCK epithelial cells. Before any further clinical study, the UV full-length absorption of TAT-SOD protein was measured. The results showed the potential UV protective effect of TAT-SOD was not due to the physical absorption of UV irradiation. In a preclinical study with five healthy volunteers, the penetration of TAT-SOD through human stratum corneum on the inner upper arm was identified by the tape stripping and specific SOD activity analysis. Significant increases on SOD activity were found on the outer layers of stratum corneum in TAT-SOD treated group, compared to placebo treated control, indicating that the TAT peptide assisted SOD to penetrate into the human stratum corneum . In a clinical study with ten healthy volunteers, eight showed a significant increase of minimal erythema dose (MED) with TAT-SOD pre-treatment. The median blood flow value of ten subjects at the UVB-irradiated site decreased with TAT-SOD pretreatment. Taken together, this evidence showed that TATvi SOD did have a marked protective effect against UVB induced skin damage. In a second clinical study, five healthy volunteers were challenged with a series of UVB doses. Skin punch biopsies were taken from four test sites on the lower back for H&E and immunohistochemical staining analysis. UVB-induced apoptotic sunburn cell (SBC) formation, p53 up-regulation and thymine dimer formation in epidermis were not attenuated by pretreatment with TAT-SOD. These data suggest that transdermal superoxide scavenger TAT-SOD reduced the UVB-induced inflammation, but did not abrogate the direct DNA damage of UVB irradiation on the skin. However, the hope of TAT-SOD could reduce UVA indirect DNA damage remains.

Student Number : 0006329K - MSc(Eng) Dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Geometric optimisations are presented for the UTD in SuperNEC which is a commercial electromagnetic software package. Path finding optimisations rapidly find propagation paths of electromagnetic waves by using back face culling to determine the visible plates of polyhedral structures and by using reflection and diffraction zones which use image theory and the law of diffraction to determine illuminated spatial regions. An octree reduces the number of intersections during the shadow tests. Numerical results show that overall the optimisations halve the run time of the software for models which consist of plates and cylinders. The path finding optimisations do not scale with model size, are limited to plates and introduce errors. The mean absolute error due to the path finding optimisations is on average 0:02 dB for first order rays and 0:17 dB for second order rays. The octree optimisation scales with model size, can be used with any geometry and any type of ray and does not cause errors.