There is a call to elucidate the poorly understood link between perivascular adipose tissue (PVAT) and nervous systems controlling the vasculature. The principle aims of this study were to investigate the expression of sympathetic and sensory nerves in PVAT of rat mesenteric arteries, to characterize their role(s) in vascular tone and to investigate the interaction between these nervous systems and PVAT-derived vasoactive compounds. Immunofluorescence staining was employed to investigate the localisation of sympathetic and sensory nerves in mesenteric arteries. Rat mesenteric arterial beds (MABs; with and without PVAT, removed by careful dissection) were perfused with Krebs’-Henseleit buffer and changes in pressure recorded, or different sized rat mesenteric arteries (MA), rat abdominal aortas, porcine splenic arteries (PSA) and porcine coronary arteries (PCA) (with and without PVAT, removed by careful dissection) were isolated and set up for isometric recording. Responses to electrical field stimulation (EFS) were obtained under basal and raised tone conditions induced by methoxamine, an α1-adrenoceptor agonist,‎ in the presence and absence of agonists/antagonists. Enzyme immunoassay (EIA) was conducted to quantify capsaicin-evoked calcitonin gene-related peptide (CGRP) release of different mesenteric arterial segments and the dissected PVAT. A multiplex assay was carried out to investigate the link between sympathetic and sensory nerves and PVAT-derived vasoactive compounds. Immunofluorescence showed the presence of both tyrosine hydroxylase (TH; the rate-limiting enzyme of catecholamine biosynthesis)-immunoreactive and CGRP (the principal neurotransmitter for sensory nerves)-immunoreactive nerves at the adventitia and within PVAT. EFS elicited frequency-dependent vasoconstriction of the mesenteric beds. These responses were abolished by guanethidine, a sympathetic nerve blocker, indicating an involvement of sympathetic nerves. In the absence of PVAT, neurogenic contractile responses were markedly attenuated. There was no significant difference in concentration-dependent contractions to methoxamine in preparations with and without PVAT, thus suggesting that vascular smooth muscle remains intact in PVAT-denuded preparations. Contractile responses to EFS were significantly decreased after Krebs’-Henseleit solution containing PVAT was transferred to preparation without PVAT, indicating PVAT contains transferrable factor/s. Incubation with candesartan, but not losartan, angiotensin II receptor inhibitors, in the presence of PVAT significantly attenuated EFS-evoked contraction, indicating a potential involvement of PVAT-derived angiotensin II in PVAT-enhanced neurogenic contractile response. In PSA, removal of PVAT significantly attenuated EFS-evoked contractile responses. Exogenous methyl palmitate had no effect on sympathetic neurogenic contractions while exogenous apelin-13 reduced sympathetic responses in both PVAT-intact and PVAT-denuded PSAs. EFS of PVAT-intact MABs in the presence of guanethidine and methoxamine elicited frequency-dependent vasodilatation due to stimulation of sensory nerves. Neurogenic vasodilatation was abolished in preparations with PVAT removed. In contrast, dose-dependent vasodilator responses to capsaicin, an agonist at vanilloid receptor subtype 1 (TRPV1), and exogenous CGRP, were comparable between PVAT-intact and PVAT-denuded preparations. This suggests that the PVAT removal procedures did not damage vascular smooth muscle relaxation in PVAT-denuded preparations. Myography experiments revealed that EFS-evoked vasodilator responses were greater in PVAT-intact preparations than in PVAT-denuded preparations in both MA and second order MA (2OMA) segments. EIA indicated that CGRP release was greater in dissected PVAT with capsaicin compared to dissected PVAT without capsaicin in 2OMA preparations, which further supports the concept of the presence of sensory nerves in PVAT of MABs. Sodium sulfide (Na2S), a hydrogen sulphide (H2S) donor, caused concentration-dependent vasodilation and this effect was attenuated by incubation with HC030031, a TRPA1 antagonist, and pre-treatment with capsaicin. The vasodilator response was greatly attenuated in the second response curve, indicating the involvement of desensitization mechanism. EFS elicited frequency-dependent vasodilatation due to stimulation of sensory nerves but these responses were attenuated in the presence of Na2S. Incubation with H2S-synthesizing enzyme inhibitors, DL-propargylglycine, aminooxyacetic-acid and aspartate, had no significant effect on EFS-evoked neurogenic vasodilatation. The presence of PVAT enhanced leptin release under normal oxygenation (95 % O2 and 5 % CO2), while gassing with 95 % N2 and 5 % CO2 enhanced interleukin-6. Leptin release was enhanced during EFS of sympathetic nerves under low oxygen level and EFS of sensory nerves under normal oxygen level in the presence of PVAT. In conclusion, the present study provides clear evidence for the expression of sympathetic and sensory nerves within PVAT of mesenteric arteries and shows these nerves contribute to the regulation of vascular tone. H2S causes vasodilatation of MABs by activating sensory nerves through the TRPA1 signalling pathway, and subsequently impairs sensory nerve function, demonstrating a capsaicin-like action. H2S-producing enzymes and endogenous H2S are not involved in EFS-evoked neurogenic vasodilator responses under the conditions of the present study. Activation of sympathetic and sensory nerves in PVAT can modify PVAT-derived mediator(s) release. Collectively, these data show that sympathetic and sensory nerves are expressed in PVAT and have functional roles in modulation of vascular contractility and PVAT-derived mediator release.

Recovery from a stroke is affected by a wide range of factors. A multitude of comorbidities, including old age and diabetes, all increase the risk of death or disability as a result of a stroke. In addition, medical complications can affect stroke outcome. Infections are known to increase the risk of death or disability when contracted in the first week after stroke onset. However, by analysing data from a clinical trial, we have found that infections are actually detrimental for a lot longer than one week. Any infection acquired in the first 76 days after stroke increases the risk of death in comparison to patients with other post-stroke medical complications. Additionally, patients who contract infections and survive up to 90 days post-stroke have more disabilities and are more reliant on assistance compared to stroke patients who did not acquire medical complications. Inflammation has been identified as a possible cause for the effect of infection and requires further investigation. Neuroinflammation is a firmly established response to stroke and inflammatory processes within the stroke infarct are well characterised. But inflammation in other brain regions, not directly affect by the stroke, receives less attention. Using immunohistochemistry techniques, we looked at microglia number and activation over 28 days post-stroke in nine different regions across the rodent brain, ranging from the prefrontal cortex to the substantia nigra. Microglia activation was present in all assessed brain regions at least once between 1 and 7 days post-stroke, showing that the neuroinflammatory response to a stroke is not limited to the stroke infarct, but instead encompasses the whole brain. In light of this, it is feasible that changes in neuroinflammation will contribute to the detrimental effects of post-stroke infection. We developed an animal model of infection at a chronic time point post-stroke by administering lipopolysaccharide (LPS) intraperitoneally at 15 days post-stroke. Not only did this initiate a peripheral inflammatory response and increased in symptoms of sickness, but in stroke animals the administration of LPS increased microglia activation in the stroke-affected striatum and decreased microglia activation in the prefrontal cortex compared to controls. This supports a possible role of neuroinflammation in propagating disability after infection. While the LPS model would be useful for investigating the role of neuroinflammation further this model does not account for other comorbidities which may also have an effect. Animal models incorporating multiple comorbidities common in stroke patients are rarely used. We aimed to develop a comorbid animal model which could be used in stroke research by administering 12 month old rats a high fat diet. Although these aged obese animals successfully underwent several procedures common in stroke research, they did not develop additional desired comorbidities such as insulin resistance, diabetes and hypertension. This limits their usefulness in stroke research. Overall, a range of work has been completed highlighting a number of areas in stroke research. While some of the work has limited potential, the detrimental effect of infections acquired post-stroke requires further attention with research needed to investigate its mechanisms and possible therapeutics. The LPS model of chronic post-stroke infection is an ideal model for this work.

The mechanisms involved in the cause and progression of chronic neurodegenerative diseases are still unclear. The ubiquitin proteasome system (UPS) plays an essential role in the maintenance of intracellular protein homeostasis by degrading unwanted proteins. The accumulation of ubiquitinated proteins is a hallmark of major neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases. In most cases, these diseases are also associated with changes in cytoskeletal proteins and microtubule stability. We previously reported decreased levels of microtubule destabilizing protein stathmin (STMN) following 26S proteasome dysfunction in mouse cortical neurons; associated with neurodegeneration and the formation of intraneuronal protein inclusions in surviving neurons. This suggested a role for the 26S proteasome in maintaining the neuronal cytoskeleton. This thesis investigates the levels and localisation of cytoskeletal proteins in mouse cortical neurons following 26S proteasome dysfunction (Psmc1fl/fl;CaMKIIα-Cre). This study provides new insights into the role of the UPS in maintain cytoskeletal proteins that may be important in neurodegenerative disease. We found an early increase in neurofilaments following 26S proteasome dysfunction; before obvious changes in microtubule stability. An increased free/polymerised tubulin ratio was evident at later stages indicative of microtubule instability in Psmc1fl/fl;CaMKIIα-Cre mice. In addition, we found decreased levels of microtubule proteins, microtubule-associated proteins and detyrosinated-tubulin; with increased tyrosinated-tubulin following 26S proteasome dysfunction. These changes are contrary to decreased STMN expression observed in Psmc1fl/fl;CaMKIIα-Cre mice. We suggest that decreasing STMN may be part of a negative feedback loop to stabilize MT following 26S proteasome dysfunction. STMN is known to be a downstream target of p53, p27 and the PI3K/Akt pathway. We found expression of p53 was increased in the cortex following 26S proteasome dysfunction, correlating with decreased phosphorylated-Akt expression at an early stage and may effect STMN expression. However, we did not observe any significant differences in pro- and anti-apoptotic proteins of the Bcl-2 family between control and Psmc1fl/fl;CaMKIIα-Cre mice, which may also by effected by p53 and phosphorylated-Akt. Immunohistochemical studies revealed changes in cortical neuron morphology accompanied 26S proteasome dysfunction. Cortical thickness was significantly decreased; associated with less neurons in the layers III and V. However, nuclear size of cortical neurons was increased, as well as the length and arborisation of their apical dendrites. Taken together, our novel data contributes to our understanding of molecular and cellular events underlying neurodegeneration and suggest that control of microtubule changes may help to slow or restore pathology of neurons.

This project aimed to prove the existence of fine subdural veins hypothesised to be the source of intracranial bleeding seen in cases of accidental and non-accidental traumatic head injuries, and consequently illustrate their anatomical structure. This was important in contributing towards establishing the causal mechanism for traumatic intracranial bleeding, and was particularly applicable in unexplained traumatic head injuries in cases of possible child abuse. These issues are on-going, worldwide concerns that have been of public as well as scientific concern for many years. To illustrate the fine cerebral vessels, a unique modelling technique was recently developed involving polyurethane resin casting of the brain vasculature. Rat, marmoset, rhesus macaque and human brain tissue were all used. Tissue surrounding the resin perfused vessels were then either macerated to reveal the whole cast, or dissected to illustrate the cast as it would appear in situ. To allow analysis of these fine subdural vessels, various imaging techniques including fluorescence microscopy, light microscopy, confocal microscopy, scanning electron microscopy, transmission electron microscopy, magnetic resonance imaging, micro-computed tomography and 3D X-ray microscopy were used. The existence of subdural vessels was clearly illustrated via gross dissection of both primate and cadaveric material. Fluorescence imaging of resin-filled rat brain histological sections also showed orientation of fine vessels within the subdural space. Magnetic resonance imaging of the human head in vivo, as well as cadaveric material have shown signs of small calibre vessels that have never been previously documented, that are too fine to be bridging veins, yet seem to drain into the superior sagittal sinus. These results prove the existence of subdural vessels, present in a range of different species. Future work will further illustrate the exact morphological structure of these vessels, and biomechanical modelling will be applied to determine the exact forces required to cause them to rupture.

The prevalence of cardiovascular disease is lower in premenopausal women compared to age-matched males and postmenopausal females. Differences in risk may be due to sex differences in endothelial function. Therefore, this thesis examined the effects of gender on endothelium-dependent vasorelaxation in porcine isolated coronary arteries (PCAs). Distal PCAs were studied under myographic conditions and pre-contracted with U46619. Concentration-response curves to bradykinin, an endothelium-dependent vasorelaxant, were constructed in the presence of various inhibitors. Inhibition of NO and prostanoid synthesis (EDH-type response) produced greater inhibition in males compared to females. Eliminating H2O2 using PEG-catalase significantly reduced the bradykinin-induced vasorelaxation in the absence, but not in the presence of L-NAME and indomethacin in females, and had no effect in males. Inhibition of gap junctions with carbenoxolone and 18α-GA inhibited the EDH-type response in females but not in males. Inhibition of SKCa channels reduced the EDH-type response in PCAs from both sexes but inhibition of IKCa had an effect only in females but not males. Western blot did not detect any differences in the expression of Cx40, 43 or IKCa between sexes. H2O2 caused concentration-dependent vasorelaxations which were significantly inhibited by PEG-catalase, TEA, 60 mM K+ and 500 nM ouabain. Inhibition of NOS, cyclo-oxygenase, gap junctions, SKCa, IKCa, BKCa, Kir, KV, KATP, cGMP, Na+-Ca2+ exchanger or removal of endothelium had no effect on the H2O2-induced vasorelaxation. 1 mM H2O2 inhibited both KCl-induced vasorelaxation and rubidium-uptake consistent with inhibition of the Na+/K+-pump activity. The effects of the antioxidant Tiron® under different gassing conditions (95% O2/5% CO2 or 95% air/5% CO2) were investigated. The bradykinin-induced vasorelaxations in PCAs were unaffected by different levels of oxygenation. Tiron® increased the potency of bradykinin only when gassed with 95% O2/5% CO2 and the enhancement in vasorelaxation was prevented by catalase. Similarly, Tiron® enhanced the EDH-type response when gassed with 95% O2/5% CO2 in PCAs from both sexes. Biochemical analysis using Amplex Red demonstrated that H2O2 was generated in Krebs’-Henseleit solution when gassed with 95% O2/5% CO2, but not with 95% air/5% CO2. Inhibition of Nox had no effect in PCAs from females but DPI, a non-selective Nox inhibitor reduced the potency of the bradykinin-induced vasorelaxation in males. In the EDH-type responses, inhibition of Nox had no effect in females, but in males, ML-171 (a selective Nox inhibitor) and DPI enhances while VAS2870 (a selective Nox inhibitor) reduces the bradykinin-induced vasorelaxation. ML-171 had no effect on the forskolin-induced vasorelaxation but decreased the potency of U46619-induced tone in both sexes in the absence or presence of endothelium. Nox activity was reduced by DPI and ML-171, but not VAS2870 in PCAs from both sexes. Sex differences in the functional study of Nox could be attributed to the differential expression of Nox proteins where expression of Nox1 and Nox2 were greater in males but Nox4 was greater in females. This may underlie the greater oxidative stress observed in males. Bradykinin-induced EDH-type responses in PCAs from both sexes were essentially abolished by 2-APB (TRPC&TRPM antagonist). SKF96365 (TRPC antagonist) inhibited the bradykinin-induced vasorelaxation in males, and EDH-type response in both sexes. Pyr3 (TRPC3 antagonist) inhibited both the NO and EDH components of the bradykinin-induced vasorelaxation in males, but not females. RN1734 (TRPV4 antagonist) reduced the potency of the NO component of the bradykinin-induced vasorelaxation in females only, but inhibited the EDH-type response in both sexes. 2-APB, SKF96365 and RN1734 all reduced the H2O2-induced vasorelaxation, whereas Pyr3 had no effect. No differences in expression level of TRPC3 and TRPV4 between sexes were detected using Western blot. In conclusion, present study demonstrated clear sex differences in endothelial function in PCAs where H2O2, MEGJs, IKCa and TRPV4 channels play a role in the bradykinin-induced vasorelaxation only in female pigs while Nox-generated reactive oxygen species and TRPC3 channels play a role in the bradykinin-induced vasorelaxation only in male pigs. Therefore, gender-specific drug treatment for cardiovascular disease may be a novel therapeutic strategy.

L’étude présentée s’inscrit dans le cadre général de l’amélioration de la fiabilité mécanique des composants électroniques. Les composants de type WL-CSP (Wafer-Level Chip-Scale Package : boîtier aux dimensions comparables à celles de la puce) sont couramment utilisés dans les appareils nomades (par exemple les téléphones) et assurent de nombreuses fonctions. La tenue dans le temps de ces appareils passe par l’allongement de la durée de vie de leurs éléments. Ce sujet est une problématique complexe car la structure des composants peut varier selon les technologies employées et nécessite des essais spécifiques, qui consomment beaucoup de temps et de ressources.Un modèle numérique est développé afin d’accélérer le développement des boîtiers de ces composants et d’optimiser les ressources disponibles. Des essais de fiabilité sont menés sur le test de chute et un banc d’essai de flexion est mis en place. Les résultats de ces essais permettent de valider la simulation numérique et de mettre au point un modèle de fatigue.D’autre part, une campagne de caractérisation des matériaux permet de déterminer les propriétés mécaniques de la structure étudiée. La caractérisation concerne notamment les couches minces pour lesquelles les propriétés mécaniques sont fortement dépendantes de leurs conditions de dépôts.Ces éléments sont incorporés dans un modèle numérique incluant un certain nombre d’hypothèses. Le modèle est confronté à l’expérience pour déterminer les constantes d’un modèle de fatigue. Ensuite, la simulation et le modèle de fatigue sont utilisés conjointement pour évaluer l’influence de paramètres géométriques et matériaux sur la fiabilité des composants de type WL-CSP. / The work described in this report is related to the mechanical improvement of electronicdevices mechanical reliability. WL-CSP (Wafer-Level Chip-Scale Package) components are widely used in handheld devices and run many functions. The longevity increase of such adevice necessarily requires progresses in its components reliability. This subject is complexas the component structure can vary depending on the employed technologies. So, it requires time and ressources.A numerical model is developed to enhance the packages development as well as available resources. Reliability tests are performed on the drop-test bench and a bend-testbench is designed. These tests provide results to validate the numerical results and to establish a fatigue model.Aside from these tests, the component materials are characterized to determine the studied structure properties. It specifically concerns the thin layers for which mechanical properties strongly depends on the deposition process. All of this is incorporated in a numerical model which includes hypotheses. The model is compared with the experiments to determine fatigue model constants. Then, modeling and experiments are used together to evaluate material and geometrical parameters influence.

Stroke is a major cause of physical disability. Recovery is possible, and can continue indefinitely. As such, much of it will take place at home, often with minimal support from professional therapists. As computing becomes more pervasive and familiar, opportunities exist to design technology to support rehabilitation in the home environment. However, given the varied nature of disabilities caused by stroke, there is a need for a greater understanding of how to design technology that is sufficiently tailored to the needs of individuals and which is appropriate for usage in their homes. This thesis offers an exploration of these issues, through a series of research activities constructed around the direct participation of stroke survivors and their families. The core of this thesis begins with a consideration of a focus group which was attended by survivors of stroke and their partners. Recorded discussions provide a rich insight into their collective experience of living with stroke, and the implications of these findings for the design of effective rehabilitation technologies are considered. The design of bespoke technologies which were directly tailored to the rehabilitational needs and personal motivations of four stroke survivors is then described. Prototypes of these technologies were deployed for periods ranging from one to seven months. Data recorded throughout this entire process provides a detailed understanding of the factors that have influenced their design, use and impact. Through an analysis of material collected during all of these engagements, this thesis presents a set of contributions which can support the design of better home-based rehabilitation technologies in the future. These contributions support a more general understanding of the interactional needs of individuals who have experienced a dramatic and potentially traumatic change in their life, and of mechanisms for tailoring persuasive computing technologies to the specific motivations of those who use them.

This thesis explores the role of a large-scale brain network comprising of the insula and anterior cingulate cortex in the pathophysiology of psychosis using structural and functional neuroimaging. Primarily, anatomical changes affecting the grey matter structure and patterns of dysconnectivity involving the insula are investigated. Various meta-analytic studies have reported consistent reduction in insular grey matter across various psychotic disorders. Despite these robust observations, the role played by this brain region in the generation of psychotic symptoms remains unexplored. In this thesis, using a meta-analytic approach, the relevance of insula for the clinical expression of psychosis is highlighted. Further, significant reduction in the cortical folding of the insula was noted in patients with schizophrenia. Reduced gyrification is accompanied by reduced functional connectivity between the insula and the rest of the brain. Using an effective connectivity approach (Granger Causal Analysis), the primacy of insula in driving the dorsolateral prefrontal cortex is demonstrated in healthy controls; this relationship is significantly affected in schizophrenia amounting to aberrant connectivity within a putative salience-execution loop. Reduced primacy of the salience-execution loop relates to illness severity. It is argued that the insula, as a key region of the salience network, plays a crucial role in the generation of symptoms of psychosis. The evidence in support of this theory is discussed, together with its implications for clinical practice aimed at reducing the burden of psychosis.

Background: Many HIV/AIDS patients experience pain. This is often associated with advanced HIV/AIDS infection and side effects of treatment. In sub-Saharan Africa, pain management for people with HIV/AIDS is suboptimal. With survival extended as a direct consequence of improved access to antiretroviral therapy, the prevalence of HIV/AIDS related pain is increasing. As most care is provided at home, the management of pain requires patient and family involvement. Pain education is an important aspect in the management of pain in HIV/AIDS patients. Aim: The aim of this study was to evaluate the effects of a pain educational intervention on pain severity and pain related outcomes among patients with HIV/AIDS and their family carers. Methods: Two systematic reviews were conducted: (1) to examine the evidence base of the effectiveness of educational interventions delivered to people living with HIV/AIDS on pain severity, pain interference, quality of life, knowledge of pain management, and (2) To examine the evidence base of the effectiveness of educational interventions delivered to their family carers on knowledge of pain management, quality of life and carer motivation. A randomised controlled trial was conducted at the HIV and palliative care clinics of two public hospitals in Malawi. To be eligible, patient participants had a diagnosis of HIV/AIDS (stage III or IV). Carer participants were individuals most involved in the patient’s unpaid care. Eligible participants were randomised to either: (1) a 30-minute face–to-face educational intervention covering pain assessment and management, augmented by a leaflet and follow-up telephone call at two weeks; or (2) usual care. Those allocated to the usual care group receive the educational intervention after follow-up assessments had been conducted (wait-list control group). The primary outcome was average pain severity measured by the Brief Pain Inventory. Secondary outcomes were pain interference, patient knowledge of pain management, patient quality of life. Carer outcomes were; carer knowledge of pain management, caregiver motivation and carer quality of life. Follow-up assessments were conducted eight weeks after randomisation by nurses’ blind to allocation. Results: Systematic review Eight published randomised controlled trials of educational interventions among patients with HIV/AIDS were identified. Only one study examined the effect on pain severity but the results were not statistically significant. Three studies reported positive effects in improving severity and frequency of symptoms, three reported improvement in quality of life and two studies found improvement in knowledge. Seven published studies of family carers of HIV/AIDS patients were identified. Only three of which were randomised controlled trials. Five of these reported that educational interventions were effective in reducing psychosocial outcomes. Two studies reported that the interventions improved knowledge outcomes among family carers of HIV/AIDS patients. Trial Of the 182 patients/carers dyads randomised; 167 patients and 157 carers completed the trial. At follow-up, patients in the intervention group experienced a greater decrease in average pain severity score 21.25 (mean difference 21.25, 95% confidence interval 16.7 to 25.8; P <0.001). Patients in the intervention group reported, less pain interference (mean difference 24.5, 95% confidence interval 19.61 to 29.38; P<0.001), had improved knowledge of pain management (mean difference 20.39, 95% confidence interval 17.51 to 23.27; P<0.001), and a better quality of life (mean difference 28.76, 95% confidence interval 24.62 to 32.91; P<0.001). At follow-up carers in the intervention group had improved knowledge (mean difference 20.32, 95% confidence interval 17.37 to 23.28; P<0.001), greater motivation (mean difference 7.64, 95% confidence interval 5.15 to 10.13; P<0.001) and better quality of life (mean difference 34.16, 95% confidence interval 30.15 to 38.17; P<0.001). Conclusion: Current evidence of educational interventions among HIV/AIDS and family carers on pain severity is inconclusive and based on a relatively small number of studies, many of which have methodological problems. A relatively simple form of pain education is effective in reducing pain and improving outcomes for patients with HIV/AIDS and their carers. Greater attention needs to be given to incorporating this into the routine care of people with HIV/AIDS in sub-Saharan Africa. Trial registration: Current Controlled Trials ISRCTN72861423.

Thesis advisor: Baldassare Di Bartolo / Thesis advisor: Pradip Bakshi / The search for multicolored light produced by some IR laser-excited luminescent nano-powders has revealed, for laser power exceeding a threshold value, the emission of white light (WL) with black-body characteristics. I am directing my research to the study of the physical parameters that may influence the threshold power of the laser and the efficiency of the WL emission. A typical compound that I will investigate will consist of nano-powders of SrZrO3 doped with Yb. The parameters of relevance may include Yb concentration, pressure, temperature, size of nano-crystals, exciting power and wavelength of the laser, dynamical parameters such as decay and build-up patterns. The aim of my research will be both theoretical and experimental: theoretical for I will try to uncover the mechanism of the WL production and experimental for the possible application as efficient light sources of systems similar to the ones that I will investigate (oxide nano-powders doped with lanthanide or transition metal ions). The “new” light sources in the market (fluorescence lights sources, and LED lamps) beat the Edison bulbs in efficiency, but they do not produce the black-body emission of the Edison bulbs that is most pleasing to the eye. The search for efficient black-body type of sources is still on and we want to be a part of it. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.