Approximately one third of the genes for the completely sequenced bacterial genomes have an unknown, uncertain, or incorrect functional annotation. Approximately 11,000 putative proteins identified from the fully-sequenced microbial genomes are members of the catalytically diverse Amidohydrolase Superfamily. Members of the Amidohydrolase Superfamily separate into 24 Clusters of Orthologous Groups (cogs). Cog3653 includes proteins annotated as N-acyl-D-amino acid deacetylases (DAAs), and proteins within cog2355 are homologues to the human renal dipeptidase. The substrate profiles of three DAAs (Bb3285, Gox1177 and Sco4986) and six microbial dipeptidase (Sco3058, Gox2272, Cc2746, LmoDP, Rsp0802 and Bh2271) were examined with N-acyl-L-, N-acyl-D-, L-Xaa-L-Xaa, L-Xaa-D-Xaa and D-Xaa-L-Xaa substrate libraries. The rates of hydrolysis of the library components were determined by separating the amino acids by HPLC and quantitating the products. Gox1177 and Sco4986 hydrolyzed several N-acyl-D-amino acids, especially those where the amino acid was a hydrophobic residue. Gox1177 hydrolyzed L-Xaa-D-Xaa and N-acetyl-D-amino acids with similar catalytic efficiencies (~10⁴ M⁻¹s⁻¹). The best substrates identified for Gox1177 and Sco4986 were N-acetyl-D-Trp and N-acetyl-D-Phe, respectively. Conversely, Bb3285 hydrolyzed N-acyl-D-Glu substrates (kcat/Km ⁹́⁸ 5 x 10⁶M⁻¹s⁻¹) and, to a lesser extent, L-Xaa-D-Glu dipeptides. The structure of a DAA from A. faecalis did not help explain the substrate specificity of Bb3285. N-methylphosphonate derivatives of D-amino acids were inhibitors of the DAAs examined. The structure of Bb3285 was solved in complex with the N-methylphosphonate derivative of D-Glu or acetate/formate. The specificity of Bb3285 was due to an arginine located on a loop which varied in conformation from the A. faecalis enzyme. In a similar manner, six microbial renal dipeptidase-like proteins were screened with 55 dipeptide libraries. These enzymes hydrolyzed many dipeptides but favored L-D dipeptides. Respectable substrates were identified for proteins Bh2271 (L-Leu-D-Ala, kcat/Km = 7.4 x 10⁴ M⁻¹s⁻¹), Sco3058 (L-Arg-D-Asp, kcat/Km = 7.6 x 10⁵ M⁻¹s⁻¹), Gox2272 (L-Asn-D-Glu, kcat/Km = 4.7 x 10⁵ M⁻¹s⁻¹), Cc2746 (L-Met-D-Leu, kcat/Km = 4.6 x 10⁵ M⁻¹s⁻¹), LmoDP (L-Leu-D-Ala, kcat/Km = 1.1 x 10⁵ M⁻¹s⁻¹), Rsp0802 (L-Met-D-Leu, kcat/Km = 1.1 x 10⁵ M⁻¹s⁻¹). Phosphinate mimics of dipeptides were inhibitors of the dipeptidases. The structures of Sco3058, LmoDP and Rsp0802 were solved in complex with the pseudodipeptide mimics of L-Ala-D-Asp, L-Leu-D-Ala and L-Ala-D-Ala, respectively. The structures were used to assist in the identification of the structural determinants of substrate specificity.

No description available.

L’objectif principal de la thèse est de modéliser et visualiser les phénomènes de plastification des polymères dans le procédé d’injection-moulage. Dans les procédés de transformation des polymères par un système vis-fourreau (extrusion, injection), la plastification est l’étape durant laquelle le polymère originellement à l’état solide est graduellement fondu et homogénéisé par le chauffage externe et l’action mécanique de la friction contre les parois de l’outillage et du cisaillement. Cette étape est capitale dans la maîtrise technique et économique du procédé, en termes d’homogénéité thermique, de mélange des charges et de temps de séjour du polymère. Nous envisageons de visualiser et modéliser l’ensemble du processus de plastification dans les monovis d’injection. Afin de comprendre et de mesurer cette étape, nous avons conçu, validé et réalisé un fourreau à fenêtres. Ce système se compose de trois fenêtres de visualisation, insérées dans un fourreau en acier usiné par électroérosion. Le comportement mécanique de cet assemblage a été analysé par simulation numérique, sous différentes sollicitations thermiques, pressions et contraintes. L’hétérogénéité des matériaux de structure (acier – verre) a fait apparaître des problèmes potentiels de fuites, de fragilité qui ont été pris en compte dans la conception. Ce fourreau à fenêtres nous permet de visualiser et de suivre à l'aide des caméras scientifiques, les différents états du polymère une fois introduit dans l’ensemble vis-fourreau. Les résultats confirment les hypothèses théoriques de la plastification. Certains sont mis en évidence, comme l’existence d’un lit solide adossé à l’arrière du filet de la vis, ainsi que son évolution par rapport à la vitesse de rotation de la vis, ou l’apparition des films fondus entre le filet de la vis et le lit solide, et entre la paroi du fourreau et le lit solide. Certains sont par contre à vérifier par d’autres expériences, comme par exemple : l’apparition de la rupture du lit solide quelle que soit la vitesse de rotation de la vis, la valeur de la vitesse du lit solide par rapport à la vitesse de rotation de la vis. Nous souhaitons aussi, grâce à ce système "fourreau transparent", pouvoir étudier, modéliser et visualiser les aspects de dispersion et de mélange des charges (traceurs, pigments, mélange maître) au sein de la matrice polymère à l’état solide ou fondu. / The main objective of the thesis is modelling and visualization of the phenomena of polymer plastication in the injection-moulding process. In injection moulding or in extrusion, plastication is the step during which polymer pellets are melted by the means of mechanical dissipation provided by a rotating screw and by thermal conduction coming from a heated metallic barrel. This step is crucial for melt thermal homogeneity, charge dispersion and fibre length preservation. Although there have been a large number of theoretical and experimental studies of plastication during the past decades, mostly on extrusion and mostly using the screw extraction technique, extremely few of them have dealt with trying to visualise plastication, let alone measuring the plastication profile in real-time. As a matter of fact, designing such equipment is an arduous task. We designed an industry-sized metallic barrel, featuring 3 optical glass windows; each window possessing 3 plane faces itself to allow for visualisation and record by synchronised cameras and lightening by lasers. The mechanical behaviour of this assembly was analysed by numerical simulation under different thermal stresses, pressures and constraints. The heterogeneity of structural materials (steel - glass) showed potential leakage problems, or fragility problems, that have been taken into account in the design. We named it "transparent barrel" or "barrel with glass windows". This "transparent barrel" allows us to visualize and follow through scientific cameras, the different states of the polymer when introduced into the screw-barrel. The images recorded can be further analysed by digital image processing. Preliminary results confirm the plastication theory and show a compacted solid bed and a melt pool side by side. The total plastication length is a direct function of screw rotation frequency as it is obvious from results on the melt pool width, which increases when the screw rotation frequency decreases. However, some evidence of solid bed breakage has been recorded, whereby the solid bed does not diminish continuously along the screw but is fractured in the compression zone. Some others results need to be checked with others experiments. We also wish, through this system "transparent barrel", to study, modelling and visualize the aspects of dispersion and mixing charges (tracers, pigments, master batch) in the matrix polymer.

The aim of this diploma thesis is an attempt to reveal a regularity and dependence in spatial distribution of the pork barrel (i.e. the parliamentary grants) in the case of Czechia in 2003-2009. Moreover, the thesis attempts to identify some undermining factors of the proven spatial pattern in allocation of pork barrel financial sources. The selection of supported projects highly depends on subjective preferences of particular deputies being influenced by many factors. Accordingly, the diploma thesis examines a role of the spatial distribution of deputies' places of living and their influences on the spatial allocation of the pork barrel through the state budget being approved in the Lower House.

This study utilizes William Benoit’s Image Repair Theory to frame the dominant crisis communication strategies that fast food chain Chick-fil-A (CFA) employed before, during and after their CEO mixed his personal opinion on social issues with corporate policy in June 2012. The thematic analysis draws from three distinct data sets that include 3,900 Facebook comments posted by the general public on CFA’s social media page, 32 individual Atlanta Journal-Constitution news articles that address the debate and CFA’s public response to the crisis titled “Who We Are.” This thesis aims to identify both the dominant themes in Facebook posts and the news articles, as well as how these themes are situated within Benoit’s Image Repair Theory. Research shows that CFA representatives utilized eight of Benoit’s 14 strategies to address their CEO’s comments on gay marriage in an attempt to salvage their reputation. The transcendence strategy was used more than any other throughout the crisis. The thematic analysis of Facebook comments showed that religion and loyalty were the most addressed theme within social media users’ posts on the company’s page. Research also shows that a national boycott initiated against CFA by the LGBTQ community did not hurt the company, but may have helped to spur brand recognition and overall sales. Another pertinent question arose during this research; did company representatives purposely forgo sharing their 2011 and 2012 tax documents that prove they had already stopped contributing to supposed anti-gay organizations more than a year before the controversy arose? Was CFA benefiting from the crisis to such an extent that they strategically remained silent and allowed the misconception to take place when they could have ended the crisis and shown proof?

An extensive literature examines how distributive (i.e., “pork barrel”) spending is allocated among congressional districts. Much of this research finds evidence that intra-chamber factors like ideology, party, and committee membership are the primary determinants of various forms of distributive spending. However, we know much less about how extra-chamber factors such as district-level demand and the economy impact the distribution of federal outlays. In this study, I find that district-level demand and variation in economic factors, in particular, income and unemployment, significantly predict the distribution of new bureaucratic awards in the 110th Congress. The results support the contention that districts get what they need, and this raises questions about the ability of members of powerful committees to steer awards selectively to their districts. It also provides evidence for the economic “law of increasing state activity,” by which districts with higher income levels receive a larger share of federal assistance.

Recent evidence indicates that the mature neocortex retains a higher degree of plasticity than traditionally assumed. Up- and down-regulation of synaptic strength, long-term potentiation (LTP) and long-term depression (LTD), is thought to be the primary mechanism mediating experience-dependent plasticity of cortical networks. The present thesis investigate factors that regulate adult cortical plasticity, focusing on the role of neuromodulators, recent sensory experience, and different anatomical divisions of the cortex in influencing synaptic strength. First, I investigated the role of the neuromodulator histamine in gating plasticity in the primary visual cortex (V1) of urethane anesthetized adult rats. Histamine applied locally in V1 produced an enhancement of LTP elicited by theta burst stimulation (TBS) of dorsal lateral geniculate nucleus (dLGN) and allowed a sub-threshold TBS to produce stable LTP. Second, the impact of visual deprivation on LTP in V1 was assessed. Animals that received 2 and 5 hr dark exposure showed greater potentiation of field potentials when stimulated though retinal light flashes or weak TBS of the dLGN, which failed to induce LTP in control animals kept in continuous light. Third, I performed a detailed characterization of LTP induced by different TBS protocols, recording in either the monocular or binocular segment of both V1 hemispheres (i.e., ipsi- and contralateral to the stimulated dLGN). Stronger, NMDA receptor-independent LTP was found in the contralateral V1. Interestingly, weak TBS induced LTD that was NMDA receptor-dependent in the ipsilateral V1. Furthermore, a lower LTP induction threshold was observed in the binocular than the monocular segment of ipsilateral V1. Lastly, I investigated cholinergic modulation of sensory-induced activity in the barrel cortex. Basal forebrain stimulation enhanced multi-unit activity elicited by whisker deflection, an effect that was more pronounced for weaker response driven by a secondary whisker than principal whisker deflection. This thesis demonstrates that neocortical plasticity consists of multiple forms of synaptic modification. Adult cortical plasticity is greatly influenced by preceding activity of the synapse by various neuromodulator systems, and by anatomical subdivisions within primary sensory cortex fields. Together, these mechanisms may facilitate the detection, amplification, and storage of inputs to primary sensory fields of the neocortex. / Thesis (Ph.D, Psychology) -- Queen's University, 2010-04-29 14:02:30.742

le antocianine sono una classe di metaboliti secondari nelle piante, appartenenti ai flavonoidi, categoria di molecole antiossidanti utili per la salute di piante, animali e umana. Sono ampiamente studiati nelle Leguminosae poiché implicati in numerose funzioni fisiologiche. In questa tesi, due wild-types e cinque mutanti di Medicago truncatula, coinvolti nel metabolismo dei flavonoidi, sono stati caratterizzati a livello fenotipico, fisiologico e molecolare. La principale differenza tra i wild-type e i mutanti è la riduzione del contenuto di antocianine nelle foglie. In seguito all'esposizione alle radiazioni UV-B, è stata analizzata la loro risposta, evidenziando un diverso comportamento. Inoltre, il metabolismo delle antocianine è stato studiato anche a livello di regolazione genica e un nuovo gene myb è stato isolato e caratterizzato, risultando più espresso nei tessuti che accumulano antocianine. / Anthocyanins are secondary metabolites in plants. They belong to a class of flavonoids synthesized via the phenylpropanoid pathway and they are antioxidant molecules important for plant, animal and human health. Flavonoids are widely studied in legume because they are implicated in several biological and physiological functions. In this thesis seven genotypes (two wild-types and five indipendent mutants) of Medicago truncatula (the model legume plant) affected in flavonoid metabolism have been characterized at phenotypic, physiological and molecular level. The main difference between wild-types and mutants, is the reduction in anthocyanin content in leaves. The anthocyanin accumulation during the leaf life, the flowering time and the fruit formation have been registered and compared. The two wild-types contain 6 μg cyanidin.mg-1 of fresh weight, while in the mutants the anthocyanin amount ranged from 0.12 μg cyanidin mg-1 to 2 μg cyanidin mg-1 of fresh weight. After HPLC-DAD-MS/MS analysis, the main anthocyanin present in the two wild-types is the cyanidin-3-O feruloyl. The Expression profile of genes codifying enzymes and transcriptional factor involved in flavonoid biosynthesis has been investigated. RT-PCR and qPCR results show different possible pathways of reduction of anthocyanins in the five mutants. These mutants, have been exposed to UV-B radiations and their response has been investigated measuring the chlorophyll fluorescence parameters (Fv/Fm, qP and NPQ) in untreated plants, during treatment (after 4hrs and 14hrs of treatment) and in the recovering phase. All genotypes, regardless of the anthocyanins amount, showed a decrease of the photosyntetic efficiency after 14hrs of treatment. This indicates a marginal role of these pigments in the oxidative damages protection. Mutants do not response in the same manner to the UV—B exposure and the anthocyanin amount does not increase equally in all genotypes. The anthocyanin metabolism is studied also at the gene regulation level. A novel Myb gene (MtMYBA) involved in anthocyanin pathway has been isolated and characterized. This gene is more expressed in tissues which accumulate anthocyanins in M. truncatula plants. The functional analysis has been investigated overexpressing this Myb gene under the control of 35S promoter. This construct has been used to transform Arabisopsis thaliana and Medicago truncatula plants. In addition, the MtMYBA promoter has been cloned in a plasmids containing GUS and GFP reporter genes.

Elevation axis model of a barrel stabilization system is constructed. The nonlinearities which are considered in the model are orifice flow characteristics, coulomb friction, hard-stop limits, kinematics of the system and unbalance on the barrel. A Simulink&reg / model for the servo valve, actuation system and barrel is constructed. Servo valve identification is made via the actual test data. Compressibility of the hydraulic fluid is taken into consideration while modeling the actuation system. Friction model is simulated for different cases. Controller of the system is constructed by two PIDs, one for each of the velocity and the position loops. Velocity feed forward can reduce the time to make a quick move by the system. The disturbance is evaluated from a given road profile and disturbance feed forward is applied to the system.

Les vibrisses ou moustaches, sont représentées de façon très précise au niveau cortical. Cette représentation forme une carte qui peut varier selon l’expérience ou l’apprentissage. La plasticité corticale est parfois altérée dans des maladies. C’est le cas du syndrome de l’X-fragile où la protéine FMRP n’est plus produite. Notre hypothèse est double : 1- La plasticité opérant dans le cortex somato-sensoriel primaire lors d’un conditionnement associatif est primordiale pour l’apprentissage. 2- FMRP peut perturber cette plasticité et altérer l’acquisition de la mémoire. Mon travail de thèse s’est déroulé sous la direction du Dr Ingrid Bureau, dans l’Institut de neurobiologie de la Méditerranée UMR901, laboratoire de l’INSERM, sur le campus universitaire de Luminy (Aix-Marseille Université).Après un protocole de conditionnement, les souris ayant appris l’association présentent des réorganisations de la carte corticale sélective manifestées par une surreprésentation des vibrisses appariées au dépend des vibrisses voisines.L’étude a ensuite montré que déjà en condition naïve l’excitabilité des neurones glutamatergiques de la couche 4 est plus importante que chez les souris mutantes, dans lequel la synthèse de FMRP n’est inactivée que dans la couche 4 du cortex somato-sensoriel. Ceci est couplé à une baisse de la probabilité de libération de neurotransmetteur et une baisse de connectivité. Les cartes corticales sauvages et mutantes en condition naïve sont donc en apparence similaires. Après altération de l’expérience sensorielle, nous avons observé une forte augmentation de la force des projections ascendantes de la couche 4 vers la couche 2/3 chez les individus mutants / Whiskers representation is well defined at cortical level. This representation designs a map which can be modified with sensory experiece or learning. Cortical plasticity is sometime affected by diseases such as the fragile-X syndrome where protein FMRP is lacking. Two hypothesis : 1- Plasticity in primary somatosensory cortex play a major role in learning. 2- FMRP can disturb that plasticity and so memory acquisition.After playing an associtiative conditionning protocol, some mice learn the association and cortical map changes in a selective way with a gain of representation for the paired whiskers vs whiskers in neighbourghood.We’ve after shown that in naive conditions, layer 4 glutamatergic neurons present an increase of excitability in mutant mice, in which FMRP synthesis is inactivated only in layer 4 of somatosensory cortex. This phenotype comes with a decrease in neurotransmetor release probability and a decrease in connectivity. This way, WT and mutant cortical maps appear similar in naive conditions. But after sensory alteration we’ve seen a huge increase in strenght of ascending projections from layer 4 to layer 2/3 in mutants. We don’t know yet how to explain thoose deregulations.