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Initially, this study examined the mechanisms by which Na+ and Cl-are regulated in freshwater rainbow trout during exercise and stress. Aerobic exercise (~2 body lengths sec⁻¹) caused a brief increase in diffusive Na⁺ efflux (Jₒᵤₜᴺᵃ⁺) and a brief decline in plasma Na+ and Cl⁻. This disturbance was rapidly compensated by a 3 fold increase in Jᵢₙᴺᵃ⁺ and Jᵢₙᶜˡ⁻(over the first 10-12 h exercise), and by a reduction in Jₒᵤₜᴺᵃ⁺ to 40% of routine by 7 h of exercise. The compensation produced a significant increase in whole body Na⁺ while whole body Cl⁻ remained unchanged. In contrast, confinement stress (for 4 or 8 h) caused an 8 fold increase in Jₒᵤₜᴺᵃ⁺and Jₒᵤₜᶜˡ⁻ which was sustained for at least the first 5 h of stress and resulted in large decreases in whole body Na+ and Cl-. Compensation of the losses was not complete until 24 h post-stress and was achieved by increases in Jᵢₙᴺᵃ⁺ and Jᵢₙᶜˡ⁻ (of similar magnitude and timing to that of exercise) as well as reductions in Jₒᵤₜᴺᵃ⁺ and Jₒᵤₜᶜˡ⁻ to nearly zero. We conclude that Jᵢₙ increased because of an activation of inactive transport sites in the gills while Jₒᵤₜ was reduced by a reduction in branchial ionic permeability, both responses mediated hormonally. Although the hormonal control mechanisms are as yet poorly defined, we argue that growth hormone and prolactin are responsible for the Jᵢₙ and Jₒᵤₜ regulation, respectively, and rule out either cortisol or epinephrine as having any role, at least with respect to the rapid NaCI regulation evident during exercise. The ability of rainbow trout to rapidly regulate ion balance was then investigated to determine whether it is unique to rainbow trout, exists in stream-dwelling animals or whether it is wide spread in fish regardless of preferred habitat. Common shiners, considered to be an active species and smallmouth bass, considered to be less active, were the two species of comparison. Common shiners demonstrated rapid increases in Jᵢₙᴺᵃ⁺ during exercise and confinement, a lack of change in whole body Na⁺ and Cl⁻ during exercise and a large Na⁺ and Cl⁻ loss during stress. In contrast, smallmouth bass experienced minimal increases in Jᵢₙᴺᵃ⁺ during exercise and no change during stress with ion loss occurring during both exercise and stress. It was concluded that the relative ability to regulate ion balance in response to stress and exercise may reflect the frequency with which the animal experiences that challenge in its natural habitat. Consequently, common shiners probably possess a similar uptake mechanism to that of rainbow trout while the mechanisms in smallmouth bass may exist, but in attenuated form. The final analysis investigated whether or not exercise training affected the magnitude of the disturbance to Na⁺ balance produced by both acute and chronic stress. This was important in that it could be applied to the improvement of fish stocking techniques. Trained fish demonstrated the ability to reduce ion loss produced by stress despite significantly high levels of cortisol, glucose and oxygen consumption. Similar results were produced by both acute and chronic stress and it was established that the rainbow trout's ability to regulate ions during stress, without altering the release of cortisol and catecholamines was improved by training. / Thesis / Master of Science (MSc)

Focused ion beam/scanning electron microscopy (FIB/SEM) is a tool commonly used for applications including preparation of site-specific transmission electron microscopy (TEM) samples, nanotomography, and electronic circuit edit. Another potential application is optical device prototyping; however, the ion beam itself has been shown to cause damage fatal to device operation. This thesis first includes several examples of FIB-fabricated optical devices that had limited functionality compared to simulation. Second, the underlying causes of ion beam-induced optical damage from gallium and xenon ion sources is characterized. Monte Carlo simulations of ion-solid interactions were confirmed using TEM analysis to measure the thickness of the damaged layer. For crystalline samples such as silicon, Raman response can be used as a measure of lattice damage. Using these techniques, it was found that optical damage from a gallium beam is more severe than from a xenon beam, and occurs in the form of lattice amorphization and implantation of beam ions. This damage hinders optical coupling by altering the physical and electronic structure of the sample. Consequently, the xenon PFIB is a better choice for optical device prototyping. / Thesis / Master of Science (MSc) / The second half of the 20th century saw the advent of nanotechnology, both in the context of understanding the structure of the natural world beyond the limit of light microscopy, as well as manipulating materials to create useful microscopic devices, including the computers ubiquitous in today’s life. One technology that has contributed to today’s nano-centric paradigm is the focused ion beam/scanning electron microscope (FIB/SEM). The FIB/SEM is used to machine materials with extreme precision for many diverse applications such as modifying microcircuits, three-dimensional (3D) nanotomography, or to prepare samples for other microscopy techniques. For some applications, however, damage to the sample from the ion beam can be fatal. New ion sources have become available in the past ten years that may cause less damage to samples, and thus open up new applications for FIB. This thesis includes first a description of a series of optical devices prototyped using FIB. This is followed by a comparison of the damage induced by the conventional liquid gallium ion source and new xenon plasma ion sources, and a discussion of the relative merits of the ion sources for optical device fabrication.

In recent years, there has been an increasing interest in the study of hydrophobic surfaces. Hydrophobic surfaces have been used in multiple applications in microfluidic devices due to their properties of self-cleaning, and also in deicing products. Conventionally, hydrophobic surfaces were created by laser cutting, self-assembly and other chemical processing methods. However, in most of these methods, hydrophobicity of the surface cannot be maintained for an extended time or restricted to limited set of materials. A low-cost, high-throughput method to generate highly hydrophobic anisotropic surface has been developed in this thesis which uses Computer Numerical Control (CNC) machining employing diamond tools whose tips have been micro-structured using Focused Ion Beam (FIB) built tips. The versatility of this method has been demonstrated by machining both metal and polymeric materials. Significant anisotropic wetting has been observed on the machined surface with the anisotropic contact angle can reach up to 71.6 degree and highly-hydrophobic property with contact angle of 163.1degree on 6061 Aluminum Alloy and 155.7 degree on PMMA surface. / Thesis / Master of Science in Mechanical Engineering (MSME)

Nickel-manganese-cobalt oxide (NMC) cathode materials have been applied in most Li-ion batteries, but there are nevertheless some concerns regarding the stability of this material. High voltage and high temperature during charging have been shown to accelerate the dissolution of NMC due to the release of more acidic components because of rapid electrolyte decomposition. Mn-contaminants (Mn2+) are hypothesized to diminish the diffusion coefficient of Li+ in the electrolyte attributed to the competitive interaction between Mn2+ ions and Li+ ions. With characterizations including 7Li and 1H pulsed field-gradient nuclear magnetic resonance (PFG-NMR) spectroscopy, we demonstrated the Mn (II)-contaminants effect on diffusion coefficient on Li+ dynamics. Under the influence of deliberate manganese salt-additive to the electrolyte, the coin cell shows a capacity fading and unstable charging behavior. The PFG-NMR measurements also validated our hypotheses, as the results showing that Mn-containment causes decrease ~15% in the diffusion coefficient on Li-self diffusion. The activation energy for lithium-ion transport over the temperature range of (273 K - 303 K), was not changed by the presence of the Mn-contaminant electrolyte, which indicates the Mn (II) does not affect the Li-ion transport mechanism. The relative test also includes comparisons with other contamination, such as iron contamination from stain-less steels spacers and copper contamination from the current collector. Additionally, the lithium self-diffusion coefficient was tested before and after charging using a full battery configuration. In electrolytes containing manganese contaminants, a more significant decrease in the diffusion coefficient was observed after charging. Ideally, operando experiments can be used to observe the impact of manganese ions on the SEI. By combining both types of experiments, a closer approximation to the actual application conditions of market-used batteries can be achieved. / Thesis / Master of Science (MSc) / The increasing maturity of lithium battery technology has also promoted the advancement of the electric vehicle manufacturing industry. As an excellent new energy material, the application and development of lithium batteries will be the main trend in the future. However, while improving battery capacity and energy density, lithium batteries also face many challenges. The entire thesis work discusses how electrolyte degradation at high temperatures and high voltages accelerates the dissolution of transition metal manganese ions in NMC materials. The dissolution of manganese ions into the electrolyte creates a competitive effect with lithium ions, thereby reducing the performance of lithium batteries. Here, NMR technology was used to measure the negative effect of manganese ions on the self-diffusion coefficient of lithium ions in the electrolyte. Additionally, a set of operando experiments conducted at different discharge rates demonstrated the changes in mossy lithium and the solid electrolyte interface during the charge and discharge phases caused by pulse discharge. This also proved that such experimental designs can track the impact of manganese ions on the solid electrolyte interface and test the dissolution behavior and impact of manganese ions under different charge and discharge rates.

No / Lymphocytes have many ion channels. These ion channels contribute to T cell-mediated autoimmune and/or inflammatory responses and therefore are targets for pharmacological immune modulation [1]. Lymphocytes are also suitable surrogate cells for cancer [2] and other diseases states [3] where inflammation is associated with increasing disease incidence. Non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, have been associated with anti-tumour effects in cancers [4]. We recently compared DNA damage caused by the nanoparticle forms (NPs) of the NSAIDs, aspirin and ibuprofen and their bulk forms in peripheral blood lymphocytes of patients with respiratory diseases and healthy individuals in the Comet and micronucleus assays [5]. In this present study, we investigate electrophysiological changes from lymphocytes after NP exposure and compare these results with their DNA damage. 10 ml peripheral blood was collected from patients and healthy control individuals. Ethical permission was obtained from the Bradford Ethics Committee REC ref no: 09/H1313/37, ReDA no: 1202, and the University of Bradford ref no: 0405/8. Ibuprofen USP was purchased from Albermarle Europe sprl (Belgium). Pharmcoat 606 (HPMC) was kindly donated by Shinetsu (Japan). Aspirin and sodium lauryl sulphate were purchased from Sigma. Kollidon 30 (PVP K-30) was purchased from BASF (UK). Bulk and nano compound suspensions of aspirin and ibuprofen (IBU) were kindly prepared by Lena Nanoceutics (Bradford, UK). Whole blood collected from healthy individuals and cancer patients were treated for 30 mins with 500µg/ml of IBU bulk and nano forms separately. Whole-cell currents were recorded with normal patch clamping technique. The extracellular solution contained (in mM) the following: NaCl 125; KCl 5; MgCl2 1; CaCl2 2.5; HEPES 10; pH 7.4. The electrode internal solution contained (in mM) the following: KF 120; MgCl2 2; HEPES 10; EGTA 10; and CaCl2 1, pH 7.4. All experiments were carried out at room temperature. Compared with untreated cells, lymphocytes treated with IBU in NP form had lower whole-cell currents and the activities of ion channels were inhibited by 20% compared to those in bulk form. This result is mirrored by the DNA damage which occurred in lymphocytes after exposure to nanoparticles [5]. Although the intracellular biochemical mechanisms and ion channels involved in our nanoparticle toxicity remain to be determined, this study provides direct evidence that 500 μg/ml IBU in nano form can cause membrane damage to lymphocytes after a relatively short exposure. Such cytotoxicity of nanoparticles in lymphocytes may be associated with early membrane damage. Further detailed investigation is needed to explain the changes of lymphocytes in response to different concentrations of NPs in real time. / Poster communications

I describe the miniaturization of a linear-type ion trap mass spectrometer for possible applications in portable chemical analysis, and demonstrate the advantages of using lithographically patterned electrode plates in realizing an ion trap with dimension r0 less than 1 mm. The focus of the work was to demonstrate the viability and feasibility of the patterned electrode approach to trap miniaturization, and also to discover potential obstacles to its use. Planar ceramic substrates were patterned with metal electrodes using photolithography. Plates that were originally used in a linear trap with a half-spacing (r0) of 2.19 mm were positioned much closer together such that r0 = 0.95 mm. A capacitive voltage divider provided different radiofrequency (RF) amplitudes to each electrode, and the capacitor values were adjusted to provide the correct electric field at this closer spacing. Electron ionization mass spectra of toluene and dichloromethane demonstrate instrument performance with better than unit mass resolution. Compared with the larger plate spacing, the signal intensity is reduced, corresponding to the reduced trapping capacity of the smaller device, but the mass resolution of the larger device is retained. A further miniaturized linear ion trap with a half-spacing of 362 µm was designed and tested. A series of obstacles and troubleshooting on ion source, analytical method, and electronics were present. These experiments show promise for further miniaturization using patterned ceramic plates and provide a guide for the ion trap miniaturization. The feasibility of a wire linear ion trap was also demonstrated. Unit mass resolution was obtained, indicating a promise for further optimization and miniaturization of the wire linear ion trap. In addition to the practical experiments on the miniaturized linear ion traps, I theoretically studied ion motion in the toroidal ion trap using SIMION simulations, which show classical chaotic behavior of single ions. The chaotic motion is a result of the non-linear components of the electric fields as established by the trap electrodes, and not by Coulombic interaction from other ions. The chaotic behavior was observed specifically in the ejection direction of ions located in non-linear resonance bands within and adjacent to the region of stable trapping. The non-linear bands crossing through the stability regions correspond to hexapole resonance conditions, while the chaotic ejection observed immediately adjacent to the stable trapping region corresponds to a "fuzzy" ejection boundary. Fractal-like patterns were obtained in a series of zoomed-in regions of the stability diagram.