Experiments presented challenge theories on their ability to provide causal explanations of the pattern of performance in dyslexia. Studies la and 1 b employed a prism adaptation paradigm to investigate the Cerebellar Deficit Hypothesis (CDH). No group differences were found, although unfortunately it was concluded that the paradigm could not satisfactorily isolate cerebellar function from other compensation mechanisms. Studies 2a and 2b exploited a sequential stereopsis technique to test the visual deficit hypothesis. No group differences were found, although the dyslexic group did exhibit a fatigue effect on one condition. Using an attention shifting paradigm, Study 3 found a dissociation between focus and shift attention conditions in dyslexic children, but that they sustained their attention as well as controls. In Study 4, supporting the Dyslexia Automatisation Deficit (DAD) as opposed to a general resources deficit, control performance suffered most under visually degraded conditions of the same attention paradigm. Study 5 further investigated attention on a test thought to be sensitive to attentional lapses; dyslexic children did make more errors, although conclusions were limited by their qualitatively normal performance. Deficits in dyslexia were found to be wider reaching than many theories of dyslexia would suggest. At a cognitive level of explanation the DAD was able to account successfully for many of the findings. However, like the Phonological Deficit Theory the DAD specifies no neurological mechanism for the deficit; this is provided by the CDH (for which no evidence was found here). Analyses do point towards the need for either a very general explanation, or the identification of a smaller number of core deficits, for the apparently disparate deficits found. The fatigue effect found only in the dyslexic group on part of the vision experiment has further direct and immediate implications for future research.

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C'est dans un contexte marqué par une demande croissante en énergie primaire, une diminution des ressources et dans un souci de protection de l'environnement que le biocarburant de 2ème génération est développé. Cependant, ce biocarburant est non viable économiquement. L’optimisation, le contrôle et la connaissance des cinétiques régissant les procédés de fabrication de ce bioéthanol sont donc des éléments capitaux. Dans cette étude, le potentiel de la calorimétrie isotherme pour surveiller les réactions d'hydrolyse et de fermentation est testé.Les résultats montrent que cette méthode est efficace. En effet, celle-ci a permis de mettre en évidence l'importance du ratio enzyme/substrat pour maximiser le rendement et de déterminer un meilleur cocktail composé de cellulases + cellobiose déshydrogénase (CDH) qui permet la production d'une certaine quantité d'acide gluconique, qui pourrait améliorer l'attractivité de ce biocarburant. Ces mêmes essais ont également permis de déterminer la chaleur de l'hydrolyse de la paille de blé, qui est 32,18 ± 3,18 J.g-1 (gramme de sucres produits).Les mesures obtenues ont été utilisées pour déterminer les constantes cinétiques des cellulases + CDH sur la paille de blé et les résultats montrent que ce cocktail enzymatique est plus rapide à 45 °C dans la gamme de températures testée (40-55°C) avec une vitesse de 7,36 ± 0,62 mmol/L.min.Par ailleurs, les essais avec un calorimètre à échelle laboratoire ont montré que même si celui-ci ne mesure pas avec précision les chaleurs engendrées par les réactions d'hydrolyse et de fermentation, celui-ci donne de bonnes indications sur le déroulement et l'avancement de ces réactions. / Second generation biofuel is developed in a context marked by an increasing demand for primary energy, a decrease in resources and in environmental protection concernsHowever, this biofuel is not economically viable. Optimization, control and knowledge of the kinetics governing this bioethanol production processes are crucial elements.In this study the potential of isothermal calorimetry to monitor hydrolysis and fermentation reactions is tested.The results show that the isothermal calorimetry is an effective method. Indeed this method allowed determining that the substrate/enzyme ratio is an important parameter of the hydrolysis yield.Furthermore it has determined a better enzyme cocktail consisting of Cellulases + Cellobiose Dehydrogenase (CDH) which allows the production of a certain amount of gluconic acid, which could improve the attractiveness of these second-generation biofuels. These same tests also determined the hydrolysis heat of wheat straw which is 32.18 ± 3.18 J.g-1 (gram reducing sugars product).The measurements obtained were used to determine kinetic constants cellulases + CDH on wheat straw and the results show that this enzyme cocktail is faster at 45 ° C in the range of temperatures tested (40 - 55°C) with a speed of 7.36 ± 0.62 mmol/L.min.In addition, testing with a laboratory-scale calorimeter showed that even if this tool does not accurately measure the heat generated by the hydrolysis reaction and fermentation, it gives a good indication of the development and advancement of these reactions.

Biological control agents are a promising niche to replace chemical pesticides for treating plant pathogens in agriculture. A potential biocontrol agent is the microparasitic fungi Clonostachys rosea which has the ability to attack various plant pathogens such as other fungi and nematodes. One key feature in the interaction between mycoparasite and prey is degradation of the fungal cell wall where cell wall degrading enzymes are important. One cell wall degrading enzyme is cellobiose dehydrogenase of which it has been found a high number of genes for in C. rosea compared to other mycoparasites. The reason for these many cellobiose dehydrogenase genes being present in C. rosea is what this study aimed to find out. To do so, the different cellobiose dehydrogenase proteins 001, 002, 003 and 004 were successfully expressed in Pichia pastoris. The 003 protein had significantly higher expression levels and were further purified with size exclusion chromatography where some of the resulting purified protein was used to set up a crystallization screen. Unfortunately, no crystals have been formed so far. The enzymatic activity against lactose, cellobiose and laminaribiose of all produced cellobiose dehydrogenase proteins were also analyzed using a 2,6-dichloroindophenol activity assay. The proteins 001 and 002 showed a low activity against lactose and cellobiose whereas the other protein showed no activity for the tested conditions. That these proteins have developed variations in their activities may be one reason for why they are all still existing.

Several hydrides of Group 2 and 12 elements were generated in the gas phase using an emission source that combines an electrical discharge with a high temperature furnace, and their high-resolution infrared emission spectra were recorded with a Fourier transform spectrometer. Two classes of molecules were studied: <em>a)</em> diatomic metal hydrides BeH, MgH, CaH, SrH, ZnH and CdH; <em>b)</em> linear triatomic metal hydrides BeH₂, MgH₂, ZnH₂ and HgH₂. <br /><br /> Infrared emission spectra of BeH, MgH, CaH, SrH, ZnH and CdH free radicals contained several vibration-rotation bands in their ²SIGMA⁺ ground electronic state. The new data were combined with all the previous ground state data from diode laser infrared spectra and pure rotation spectra available in the literature. Spectroscopic constants, i. e. , vibrational band origins, rotational, centrifugal distortion, and spin-rotation interaction constants, were determined for each observed vibrational level by least-squares fitting of all the data. In addition, the data from all isotopologues were fitted simultaneously using the empirical Dunham-type energy level expression for ²SIGMA⁺ states, and correction parameters due to the breakdown of the Born-Oppenheimer approximation were determined. The equilibrium internuclear distances (<em>r</em>_e) of ⁹BeH, ²⁴MgH, ⁴⁰CaH, ⁸⁸SrH, ⁶⁴ZnH and ¹¹⁴CdH were determined to be 1. 342424(2), 1. 729721(1), 2. 002360(1), 2. 146057(1), 1. 593478(2) and 1. 760098(3) angstroms, respectively, and the corresponding <em>r</em>^e distances for ⁹BeD, ²⁴MgD, ⁴⁰CaD, ⁸⁸SrD, ⁶⁴ZnD and ¹¹⁴CdD are 1. 341731(2), 1. 729157(1), 2. 001462(1), 2. 145073(1), 1. 593001(2) and 1. 759695(2) angstroms, respectively. <br /><br /> Gaseous BeH², MgH², ZnH² and HgH² molecules were discovered and unambiguously identified by their high-resolution infrared emission spectra. The &nu;₃ antisymmetric stretching fundamental band and several hot bands in the &nu;₃ region were rotationally analyzed, and spectroscopic constants were obtained for almost all naturally-occurring isotopologues. The rotational constants of the 000 ground states were used to determine the <em>r</em>₀ internuclear distances. For BeH₂, ZnH₂, ZnD₂, HgH₂ and HgD₂ molecules, the rotational constants of the 000, 100, 01¹0 and 001 levels were used to determine the equilibrium rotational constants (<em>B</em>_e) and the associated equilibrium internuclear distances <em>r</em>_e. The <em>r</em>_e distances of ZnH₂ and ZnD₂ differed by about 0. 01%, and those of HgH₂ and HgD₂ differed by about 0. 005%. These discrepancies were larger than the statistical uncertainties by one order of magnitude, and were attributed to the breakdown of the Born-Oppenheimer approximation.

Several hydrides of Group 2 and 12 elements were generated in the gas phase using an emission source that combines an electrical discharge with a high temperature furnace, and their high-resolution infrared emission spectra were recorded with a Fourier transform spectrometer. Two classes of molecules were studied: <em>a)</em> diatomic metal hydrides BeH, MgH, CaH, SrH, ZnH and CdH; <em>b)</em> linear triatomic metal hydrides BeH₂, MgH₂, ZnH₂ and HgH₂. <br /><br /> Infrared emission spectra of BeH, MgH, CaH, SrH, ZnH and CdH free radicals contained several vibration-rotation bands in their ²SIGMA⁺ ground electronic state. The new data were combined with all the previous ground state data from diode laser infrared spectra and pure rotation spectra available in the literature. Spectroscopic constants, i. e. , vibrational band origins, rotational, centrifugal distortion, and spin-rotation interaction constants, were determined for each observed vibrational level by least-squares fitting of all the data. In addition, the data from all isotopologues were fitted simultaneously using the empirical Dunham-type energy level expression for ²SIGMA⁺ states, and correction parameters due to the breakdown of the Born-Oppenheimer approximation were determined. The equilibrium internuclear distances (<em>r</em>_e) of ⁹BeH, ²⁴MgH, ⁴⁰CaH, ⁸⁸SrH, ⁶⁴ZnH and ¹¹⁴CdH were determined to be 1. 342424(2), 1. 729721(1), 2. 002360(1), 2. 146057(1), 1. 593478(2) and 1. 760098(3) angstroms, respectively, and the corresponding <em>r</em>^e distances for ⁹BeD, ²⁴MgD, ⁴⁰CaD, ⁸⁸SrD, ⁶⁴ZnD and ¹¹⁴CdD are 1. 341731(2), 1. 729157(1), 2. 001462(1), 2. 145073(1), 1. 593001(2) and 1. 759695(2) angstroms, respectively. <br /><br /> Gaseous BeH², MgH², ZnH² and HgH² molecules were discovered and unambiguously identified by their high-resolution infrared emission spectra. The &nu;₃ antisymmetric stretching fundamental band and several hot bands in the &nu;₃ region were rotationally analyzed, and spectroscopic constants were obtained for almost all naturally-occurring isotopologues. The rotational constants of the 000 ground states were used to determine the <em>r</em>₀ internuclear distances. For BeH₂, ZnH₂, ZnD₂, HgH₂ and HgD₂ molecules, the rotational constants of the 000, 100, 01¹0 and 001 levels were used to determine the equilibrium rotational constants (<em>B</em>_e) and the associated equilibrium internuclear distances <em>r</em>_e. The <em>r</em>_e distances of ZnH₂ and ZnD₂ differed by about 0. 01%, and those of HgH₂ and HgD₂ differed by about 0. 005%. These discrepancies were larger than the statistical uncertainties by one order of magnitude, and were attributed to the breakdown of the Born-Oppenheimer approximation.

Largely as a consequence of the ongoing obesity epidemic, research into adipose tissue biology has increased substantially in recent years. Worldwide, the number of people classed as overweight or obese is growing, and this represents a major public health concern. Adipose tissue is broadly divided into two types; white and brown. Whilst white adipose tissue (WAT) functions to store and mobilise triglycerides, brown adipose tissue burns chemical energy to generate heat. WAT is further divided into visceral “bad” fat and subcutaneous “good” fat depots, and it is an increase in the former that is linked to obesity-associated diseases. As well as adipocytes, several other cell types including haematopoietic and endothelial are found within adipose tissue, and comprise the stromal vascular fraction (SVF). Adipocyte precursor cells (APCs) also reside within the SVF and are essential for the maintenance and expansion of adipose tissue. The protein encoded by the Wilms’ tumour 1 (Wt1) gene is predominantly known to function as a transcription factor, but also has a role in post-transcriptional processing. Deletion of Wt1 in adult mice results in a considerable loss of fat tissue. Moreover, recent work has revealed that a proportion of the APCs from all visceral WAT depots express Wt1, therefore revealing heterogeneity within the APC population. Additionally, visceral WAT depots are encapsulated by a WT1 expressing mesothelial layer, which has its origins in the lateral plate mesoderm (LPM), and can give rise to mature adipocytes. Lineage tracing has demonstrated that a significant proportion of the mature adipocytes in all adult visceral WAT depots (but not subcutaneous) are derived from cells that express Wt1 in late gestation. These findings uncovered key ontogenetic differences between visceral and subcutaneous WAT and led us to ask whether Wt1 functions in visceral adipose tissue biology. Preliminary work has shown that adipocytes derived from Wt1 expressing (Wt1+) precursor cells have fewer, larger lipid droplets than those derived from non-Wt1 expressing (Wt1-) precursors. In this thesis, this heterogeneity is explored further using a Wt1GFP/+ knock-in mouse. When Wt1+ and Wt1- APCs are cultured separately, the Wt1+ population differentiate into adipocytes more readily. Moreover, the Wt1+ APCs are more proliferative than the Wt1-. Preliminary results also suggest that the Wt1+ APCs may secrete a factor(s) that causes the Wt1- APCs to exhibit improved adipogenic differentiation, a result that is supported by data from comparative transcriptomic analysis. Finally, the percentage of APCs decreases when mice are fed a high fat diet. Interestingly, this decrease is more pronounced for the Wt1+ population. Therefore, it appears that as well as exhibiting differing behaviours in vitro, the Wt1+ and Wt1- populations respond differently to physiologically relevant conditions in vivo. Whilst the LPM is a major source of visceral WAT, the origin of subcutaneous WAT is currently unknown. Here, the Prx1-Cre and Prx1-CreERT2 mouse lines are used to investigate this. It is shown that the majority of subcutaneous WAT adipocytes and APCs are labelled by Prx1-Cre, however this is not the case for most of the visceral WAT depots. The exception to this is the pericardial (heart fat) depot, in which approximately 70% of the adipocytes and 40% of the APCs are labelled. Moreover, a proportion of the Prx1-Cre labelled pericardial APCs also express Wt1, therefore suggesting additional heterogeneity. Preliminary results show that this heterogeneity may have functional consequences, at least in vitro. Additionally, lineage tracing studies suggest that the somatic LPM may be one source of subcutaneous WAT and pericardial visceral WAT Finally, it is shown that the conditional deletion of Wt1 in the Prx1-Cre lineage results in abnormal diaphragm development. Congenital diaphragmatic hernia (CDH) is severe birth defect, the etiology of which is not well understood. Here, a new model of CDH has been developed, and the cellular and molecular mechanisms responsible for the defect in this model are investigated.

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