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Franosch, Thomas. "Complex transport in strongly disordered materials". Diffusion fundamentals 16 (2011) 17, S. 1, 2011. https://ul.qucosa.de/id/qucosa%3A12695.
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Franosch, Thomas. "Complex transport in strongly disordered materials". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-184699.
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Zheleva, Zhasmina Vasileva. "Surface crystallography of complex and disordered surfaces". Thesis, University of Reading, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553057.
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Salemeh, Elie. "Periodic structures : transmission invariance and symmetry effects". Electronic Thesis or Diss., Le Mans, 2024. http://www.theses.fr/2024LEMA1010.
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Une caractéristique du régime localisé dans un milieu désordonné est l’insensibilité du speckle transmis à l’ondeincidente. En optique, l’image sur un écran du champ transmis à travers un milieu désordonné opaque - le speckle- est la même quelles que soient les conditions d’éclairage. Ce phénomène remarquable peut être expliqué parl’analyse des modes propres de transmission du matériau étudié. Le régime localisé se caractérise par laprédominance d’un unique mode, la transmission de tous les autres étant significativement plus faible. Le motifdu champ transmis est alors déterminé par ce seul mode, indépendamment de la source. Un phénomène analogueest possible dans un milieu ordonné, périodique, lorsque l’onde propagée dans le milieu est principalement portéepar un unique mode de Bloch. L’onde propagée dans le milieu périodique est alors progressivement « gelée »,présentant un même motif, quelque soit la source qui l’a générée. Le travail présenté vise à caractériser etobserver expérimentalement ce phénomène dans le cas de la propagation dans un guide d’onde périodique. Il viseaussi à caractériser ce phénomène dans le cas de la transmission à travers un réseau de diffraction. Finalementnous nous intéressons aux effets de la symétrie lorsqu’une barrière opaque est placée dans un guide d’ondespériodique, en particulier au gain de la transmission induit par la symétrieA characteristic of the localized regime in a disordered medium is the insensitivity of the transmitted speckle tothe incident wave. In optics, the image on a screen of the transmitted field through an opaque disordered medium- the speckle - remains the same regardless of the lighting conditions. This remarkable phenomenon can beexplained by analyzing the eigenmodes of transmission of the studied material. The localized regime ischaracterized by the predominance of a single mode, with the transmission of all other modes being significantlyweaker. The pattern of the transmitted field is then determined by this single mode, regardless of the source. Asimilar phenomenon is possible in an ordered, periodic medium, when the wave propagated in the medium ismainly carried by a single Bloch mode. The wave propagated in the periodic medium is then gradually "frozen",presenting the same pattern, regardless of the source that generated it. The presented work aims to characterizeand to observe experimentally this phenomenon in the case of propagation in a periodic waveguide. It also aims tocharacterize this phenomenon in the case of transmission through a diffraction grating. Finally, we are interestedin the effects of symmetry when an opaque barrier is placed in a periodic waveguide, specifically focusing on thetransmission enhancement induced by symmetry
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Caldas, Vania Santos. "Investigation of a transcription factor complex and intrinsically disordered proteins". Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17944.
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LIM domain binding protein 1 (Ldb1) is a chromatin looping factor that forms part of a transcriptional ‘pentameric complex’. Ldb1 contains two domains that are essential for looping: a self-association domain, and a LIM interaction domain (LID) that binds LIM proteins such as Lmo2, which in turn binds to DNA binding transcription factors, Tal1, E2a and Gata-1. It was proposed that the Gata-1 binding protein FOG1 could bind to the pentameric complex. GFP-tagged FOG1 was shown to bind the complex by multi angle laser light scattering, providing a mechanism by which the intrinsically weak Gata-1/FOG1 interaction is bolstered through binding to other units of the pentameric complex. Little is known about proteins that are distantly related to mammalian Ldb1. Two such proteins, Ldb1 from C. elegans and Adn1 from S. pombe were expressed in bacteria. They had generally poor solubility, but use of a maltose binding protein tag promoted solubility, and different expression systems may enable their further study. Ldb1 was reported to bind the E3 ubiquitin ligase protein, RLIM. No interaction could be detected between these proteins by yeast two-hybrid analysis using truncated or full length proteins. The interaction was detected in mammalian cells using FLAG pull-down experiments, but truncation mutants of these proteins could not be expressed. RLIM has high levels of predicted disorder, which may contribute to its degradation in both cell types. An assay was developed in which dimerization domains could stabilise disordered binding regions. Constructs containing GST, a coiled-coil domain of CtIP, or the leucine zipper of GCN4, were tethered to a test peptide and assayed for binding in yeast two-hybrid assays. The domains from CtIP and/or GCN4 allowed the interaction to be detected. Although the assay could not detect an interaction between RLIM and Ldb1, it shows promise for detecting interactions for disordered proteins, and can be adapted to different expression systems.
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Amoah, T. K. "Designer disordered complex media : hyperuniform photonic and phononic band gap materials". Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/812500/.
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In this thesis we investigate designer disordered complex media for photonics and phononics applications. Initially we focus on the photonic properties and we analyse hyperuniform disordered structures (HUDS) using numerical simulations. Photonic HUDS are a new class of photonic solids, which display large, isotropic photonic band gaps (PBG) comparable in size to the ones found in photonic crystals (PC). We review their complex interference properties, including the origin of PBGs and potential applications. HUDS combine advantages of both isotropy due to disorder (absence of long-range order) and controlled scattering properties from uniform local topology due to hyperuniformity (constrained disorder). The existence of large band gaps in HUDS contradicts the long-standing intuition that Bragg scattering and long-range translational order is required in PBG formation, and demonstrates that interactions between Mie-like local resonances and multiple scattering can induce on their own PBGs. The discussion is extended to finite height effects of planar architectures such as pseudo-band-gaps in photonic slabs as well as the vertical confinement in the presence of disorder. The particular case of a silicon-on-insulator compatible hyperuniform disordered network structure is considered for TE polarised light. We address technologically realisable designs of HUDS including localisation of light in point-defect-like optical cavities and the guiding of light in free-form PC waveguide analogues. Using finite-difference time domain and band structure computer simulations, we show that it is possible to construct optical cavities in planar hyperuniform disordered solids with isotropic band gaps that efficiently confine TE polarised radiation. We thus demonstrate that HUDS are a promising general-purpose design platform for integrated optical micro-circuitry. After analysing HUDS for photonic applications we investigate them in the context of elastic waves towards phononics applications. We demonstrate the first phononic band gaps (PnBG) for HUDS. We find that PnBGs in phononic HUDS can confine and guide elastic waves similar to photonic HUDS for EM radiation.
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McDowell, Chester Dale. "Potential heterogeneity in p53/S100B(ββ) complex". Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13845.
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Master of ScienceDepartment of Biochemistry
Jianhan Chen
Paul E. Smith
Intrinsically disordered proteins have been shown to be important in many physiological processes, including cell signaling, translation, and transcription. They are also associated with cancer, and neurodegenerative diseases. The tumor suppressor p53 contains several disordered regions, including the C-terminal negative regulatory domain (NRD). In cancer the function of p53 has been shown to be repressed by S100B(ββ) binding to p53-NRD. Binding of S100B(ββ) blocks acetylation and phosphorylation sites in the p53-NRD, which leads to tetramer dissociation and prevents p53 activation. NMR studies have shown that p53-NRD binds S100B(ββ) in a stable α-helix conformation. Interestingly, despite the well-converged and apparent rigid nature of the NMR structure ensemble, a majority of intermolecular NOEs used to calculate the NMR ensemble are very weak (≥6 Å). The final NMR structures also contains unsatisfied buried charged residues at the binding interface. It’s plausible that the p53-S100B(ββ) complex is more dynamic than previously believed. The goal of the study is to determine the potential conformational heterogeneity in p53-S100B(ββ) complex using molecular modeling. For this, five diverse structures were selected from the 40-member NMR ensemble. For each initial conformation, we performed 100 ns molecular dynamic simulations in explicit solvent to explore the structure and dynamics of the p53-NRD in complex with S100B(ββ). Several analytical tools were used to characterize the p53-NRD conformation, including root-mean squared deviation (RMSD), root-mean squared fluctuation (RMSF), and residue helicity. The accuracy of the simulations was mainly assessed by comparing with experimental NOEs. The results show that, even though the ensemble is heterogeneous it satisfies 82% of the experimental NOEs. Clustering analysis further suggests that many conformational sub-states coexist for this complex, and individual clusters appear to satisfy only subsets of NOE distances. Importantly, the buried surface analysis demonstrates that the heterogeneous ensemble generated from MD provides similar shielding of key residues, which include post-translational modification residues needed for p53 activation. This study also demonstrates that atomistic simulations can provide important insights into structure and dynamics of IDPs for understanding their biological function.
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Adams, Ruth Nanette. "An examination and evaluation of primary nursing care and treatment provided for medium stay patients at Broadmoor Special Hospital". Thesis, University of East London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286558.
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Shakhov, Alexander. "Structure-Dynamics Relationships in Complex Fluids and Disordered Porous Solids Assessed using NMR". Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-153105.
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A NMR study of the structure-dynamics relationships in heterogeneous materials is presented. In the first part, transport in soft-matter systems is studied using the pulsed field gradient NMR technique (PFG NMR). The molecular crowding effect in biological matter has been addressed using polymer solutions as model systems. By performing ensemble-based diffusion studies, the earlier obtained data on anomalous diffusion have been complemented. The transition to normal diffusion on a larger time scale has been shown. Taking advantages of the NMR approach, transport properties of microemulsions consisting of micellar colloids dissolved in liquid crystals have been investigated. The self-diffusivities measured under equilibrium conditions have shown weak correlations with microscopic ordering and macroscopic phase transitions occurring in the systems under study. The formation of micelles is shown to be decisive for macroscopic separation at the isotropic-nematic transition.
The second part of the thesis covers heterogeneous effects in diffusion for fluids in porous solids, as probed using a combination of NMR diffusometry and structure characterization methods. Ionic liquids have been investigated, revealing a complex behavior under confinement. The attempts to correlate the observed characteristics of the ionic liquids with their internal chemical structure were undertaken. Finally, the series of nanoporous glasses with tunable pore structure characteristics were studied. Strong correlations between their structure and the preparation conditions as well as between the resulting transport properties have been shown.
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Rous, Philip James. "Dynamical theories of low energy electron diffraction from disordered and complex reconstructed surfaces". Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38149.
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Cazé, Alexandre. "Emission, scattering and localization of light in complex structures : from nanoantennas to disordered media". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2013. http://tel.archives-ouvertes.fr/tel-00917876.
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Utiliser des milieux nanostructurés pour confiner la lumière permet d'augmenter l'interaction entre un émetteur et le rayonnement électromagnétique. Dans cette thèse, nous utilisons un formalisme classique (présenté au Chap. 1) pour décrire cette interaction dans différents contextes, qui peuvent être regroupés en deux parties (respectivement Parties II et III). Dans un premier temps, nous étudions l'apparition de modes localisés en champ proche de structures complexes. Nous nous intéressons à deux différents types de structures: des nanoantennes d'or et des films d'or désordonnés. Nos résultats nous permettent de discerner les modes radiatifs et non-radiatifs. Nous introduisons le concept de Cross Density Of States (CDOS) pour décrire quantitativement la cohérence spatiale intrinsèque associée à la structure modale d'un milieu complexe. Nous démontrons ainsi une réduction de l'extention spatiale des modes au voisinage de la percolation électrique des films d'or désordonnés.
Nous nous intéressons ensuite à des milieux fortement diffusants. En éclairant de telles structures par une source cohérente, on obtient une figure d'intensité complexe appelée speckle. Nous utilisons une méthode diagrammatique pour démontrer une corrélation négative entre les figures de speckle réfléchie et transmise à travers une tranche dans le régime mésoscopique. Nous nous intéressons ensuite à la corrélation C0, qui apparait lorsque la source est enfouie dans le milieu. Nous proposons une démonstration générale de l'égalité entre la corrélation C0 et les fluctuations normalisées de la LDOS, et soulignons le rôle fondamental des interactions de champ proche. Finalement, nous observons numériquement le régime de couplage fort entre un diffuseur résonnant et un mode localisé d'Anderson au sein d'un milieu désordonné 2D.
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Shakhov, Alexander [Verfasser], Rustem [Akademischer Betreuer] Valiullin, Rustem [Gutachter] Valiullin e Ernst [Gutachter] Rößler. "Structure-Dynamics Relationships in Complex Fluids and Disordered Porous Solids Assessed using NMR : Structure-Dynamics Relationships in Complex Fluidsand Disordered Porous Solids Assessed using NMR / Alexander Shakhov ; Gutachter: Rustem Valiullin, Ernst Rößler ; Betreuer: Rustem Valiullin". Leipzig : Universitätsbibliothek Leipzig, 2014. http://d-nb.info/1238789579/34.
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Bernardes, Marcos Eduardo Cordeiro. "Medium-term (months to years) morphodynamic modelling of a complex estuarine system". Thesis, University of Plymouth, 2005. http://hdl.handle.net/10026.1/1813.
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This contribution focuses on the medium-term (months to years) morphodynamic modelling of natural estuaries. A 2D morphodynamic model based on the Telemac system was calibrated and validated using extensive field measurements' at Teignmouth (UK). Statistical tools indicate that the model is capable of predicting the observed hydrodynamics with 'good' accuracy, given that measurement noise is removed. Despite some qualitative agreement, morphological predictions show a more limited skill; consistent with the current 'state of the art' in this area of scientific research. The typical long simulation times associated with process-based morphodynamic models are optimised through the successful implementation of an input reduction approach, adapted from Latteux (1995). The technique is shown to reduce the model run times by up to 85% without a significant loss in accuracy. Bathymetric surveys spanning 2 years (December 2002 to November 2004) at Teignmouth have clearly demonstrated a seasonal variability in the sediment volumes within the estuary, with accretion in the relatively energetic winter periods and erosion during the quiescent summer months. The net longer-term trend over this period is accretionary with average seabed accumulation rates of 20 cm.year"'. It is demonstrated that i f the wave stirring effect is neglected, the predictions carried out with a single grain size do not replicate the observed sediment import to the estuary from the neighbouring coastal region, due to the ebb dominated tidal regime found at Teignmouth. The importance of the combined effects of wave stirring and mixed grain sizes on reproducing the sediment import processes is confirmed by the Brier skill scores. Model predictions show a high influx of suspended sediment into the estuary in the presence of wave stirring effects at the coastal region. These sediments are advected into the estuary during the flood phase and are rapidly deposited at the outer estuary, since lag effects are neglected. The sediment input is predicted to be dominated by the finer sediment fractions (primarily silts and clays) although in very energetic conditions even granule-sized sediments can enter the estuary. Starting from an isotropic sediment distribution, a realistic spatial redistribution of sediment grain sizes is predicted, with sediments generally fining towards the shallower and upper regions of the estuary, whilst coarser grains were concentrated seawards.
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Zhu, Guang. "Wave propagation analysis in complex medium based on second strain gradient theory". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEC045.
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Dans ce travail, deux modèles enrichis décrivant respectivement un mouvement longitudinal non classique dans des tiges et un mouvement de flexion et de cisaillement non classique dans des poutres sont établis basés sur la théorie du second gradient de contrainte de Mindlin. Ce dernier peut décrire l’hétérogénéité provoquée par les interactions micro-structure dans le cadre de la mécanique des milieux continus. La modélisation multi-échelle commence par exprimer l'énergie de déformation, l'énergie cinétique et le travail virtuel effectué par des forces externes basés sur la théorie SSG. Les équations du mouvement et les conditions aux limites associées sont ensuite dérivées en utilisant le principe de Hamilton. Un modèle en cristalline pour modèle enrichi de tige est proposé pour que les interactions à longue distance correspondent à des constantes d'ordre supérieur de matériau dans la théorie de la SSG.La relation de dispersion de l'onde longitudinale non classique ainsi que les deux ondes supplémentaires apparaissant exclusivement dans le modèle de tige basé sur la théorie de la SSG est étudiée. Ensuite, on étudie également les ondes de flexion et les ondes de cisaillement non classiques, ainsi que les quatre ondes supplémentaires dans le modèle de poutre de Timoshenko basé sur la théorie de la SSG. Les recherches sont basées à la fois sur la densité modale des ondes propagées, le flux d'énergie concernant des paramètres cinétiques d'ordre supérieur, la mobilité des structures enrichies, le transfert de puissance dans l'espace et l'analyse de la réponse en fréquence pour une tige enrichie ainsi qu’une poutre enrichie à excitation forcée ponctuelle. Les résultats de réponse en fréquence sont validés par les résultats de la méthode MEF dans COMSOL.En utilisant le modèle de tige enrichie et le modèle de poutre proposés, les caractéristiques de transmission et de réflexion des vibrations via une interface plane entre deux milieux basés sur la théorie de la SSG sont étudiées. Les coefficients de transmission et de réflexion de l'onde longitudinale dans une tige enrichie et de l'onde de flexion dans une tige enrichie sont calculés. Basé sur ces coefficients, la distribution et l'atténuation de l'énergie dans les ondes réfléchies et dans les ondes transmises sont discutées. La transmission et la réflexion des ondes à travers une certaine longueur de tige basée sur la théorie SSG sont ensuite étudiées.En utilisant le modèle de poutre enrichie, le rayonnement d'onde provenant d'une surface vibrante infinie d’une poutre enrichie basée sur la théorie SSG est étudié. Les caractéristiques enrichies, y compris la vitesse carrée de la surface vibrante, l'impédance de rayonnement et le champ de pression rayonné, sont calculées et interprétées en se combinant au caractère de propagation des ondes dans une structure de poutre enrichie. Ensuite, le rayonnement d'onde provenant d'une poutre simplement supportée est étudié en utilisant la formulation intégrale à limite directe basée sur le théorème d'intégrale de Kirchhoff-Helmholtz. Les influences des effets de micro-structure locale sont discutées et bien interprétées sur la base des résultats du modèle SSG et du modèle classiqueIn this work, two enriched models respectively describing non-classical longitudinal motion in bars, and non-classical bending and shear motion in beams, are established based on Mindlin's Second Strain Gradient (SSG) theory. The latter can describe heterogeneity caused by complex micro-structure interaction in the frame of continuum mechanics. The multi-scale modelling starts with expressing the SSG theory based strain energy, kinetic energy and virtual work done by external forces, then the governing equations and the associated boundary conditions are derived with the utilization of Hamilton principle. Lattice model corresponding to 1D longitudinal motion is proposed to map the long range interactions to higher order material constants in SSG theory.Due to the local behavior of underlying micro-structures, Wave propagation features in SSG theory continua are significantly different. With the formulated SSG theory based rod model, dispersion relation of non-classical longitudinal wave accompanying with two evanescent waves are investigated. Meanwhile, non-classical bending wave and shear wave together with four evanescent waves are also investigated with the SSG theory based Timoshenko beam model. The investigations are based on the modal density of the propagating waves, energy flow involving higher order kinetic parameters, mobility of the non-classical structures, vibrating power transfer in spatial position, and forced response analysis of enriched rod as well as enriched beam. The frequency response results are validated by FEM approach resulting from COMSOL.With employing the proposed enriched rod model and beam model, vibration transmission and reflection characteristics through planar interface between two SSG theory based mediums are studied. The study is conducted on transmission and reflection coefficients of longitudinal wave in non-classical rod, and bending wave in non-classical beam, based on which energy distribution and attenuation in reflected waves and in transmitted waves are discussed. Wave transmission and reflection through a certain length of SSG theory based rod is also investigated.With utilization of the derived enriched beam model, wave radiation from infinite vibrating surface is studied. Radiation characteristics including square velocity of the vibrating surface, radiation impedance and radiated pressure field are achieved, and these enriched characteristics are interpreted combining with wave propagation characters in non-classical beam structure. Wave radiation from baffled finite beam is investigated with employing the direct boundary integral formulation based on the Kirchhoff-Helmholtz integral theorem.The influences of local behavior caused by complex micro-structure interactions are discussed and well interpreted based on results of SSG model and classical model
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Dyer, Wendy A. "The identification of the careers of mentally disordered offenders using cluster analysis in a complex realist framework". Thesis, Durham University, 2001. http://etheses.dur.ac.uk/4268/.
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Custody diversion teams were introduced in order to divert mentally disordered offenders away from the criminal justice system and custody because of concerns about the growing prevalence of psychiatric disorder in prison populations. This research explores the impact of one such team on the psychiatric and criminal careers of people referred to it. The framework provided by a complex realist approach, along with the technique cluster analysis, were used to identify and map the different institutional careers experienced by people referred to the Cleveland Diversion Team and the different paths their careers took as a consequence of the team's actions. Five different types of career were identified. Careers One and Two describe experiences of criminalisation - violent offenders with no psychiatric history who were referred, assessed and diagnosed but had no health or social care needs identified and were not referred again. Careers Three and Four describe experiences of criminalisation - violent offenders with a psychiatric history half of whom (Career Three) were referred, assessed and diagnosed, had health or social care needs identified and were not referred again; the remainder (Career Four) were not assessed or diagnosed, nor did they have needs identified and consequently all were re-referred repeatedly. Career Five represents neither medicalisation or criminalisation - individuals referred for information and for whom little else is known. The implications of these findings include re-focusing the diversion service on Careers Three and Four. This would avoid stigmatising Careers One and Two and achieve positive outcomes by assessing and meeting the needs of all those in Careers Three and Four. In addition there is the promising application of this methodology elsewhere in other research which involves the analysis of large and complex datasets describing social processes.
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Sperber, Tom. "Control of light in a disordered medium with gain : wavefront-shaping the pump in fiber amplifiers and fiber lasers". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS366.
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L'émergence récente des techniques de façonnage spatial a démontré la possibilité de contrôler la propagation de la lumière à travers des milieux désordonnés, telles que des fibres multimodes. Le cas particulier d'une fibre multimode à gain présente une complexité supplémentaire, car la pompe, elle-même multimode, peut agir sur le signal dans des profils d'amplification spatialement complexes. Le gain hétérogène résultant est donc équivalent à un processus de diffusion non unitaire. Ces systèmes peuvent trouver leur applications plusieurs domaines, notamment les communications optiques, les lasers à fibre de haute puissance, et les lasers aléatoires. Dans ce travail, nous considérons une fibre multimode dopée par un élément de terre rare et pompée par une pompe cohérent dont le faisceau passe par un schéma de mise en forme de front d’onde. Cette architecture nous permet de configurer la composition modale de l’excitation dans la fibre. Nous explorons la possibilité d'exploiter les degrés de liberté ainsi offerts dans le pompage pour contrôler le signal en sortie. Un modèle théorique et son implémentation numérique permettent de quantifier les degrés de contrôle réalisable, tout en révélant les mécanismes fondamentaux qui les limitent. Dans une configuration d’amplificateur, les expériences ont permis de valider les prédictions du modèle en montrant un effet significatif du façonnage de la pompe sur le speckle à la sortie de l’amplificateur. Dans une configuration de la cavité d'effet laser, les travaux expérimentaux ont démontré la capacité du schéma de modulation de favoriser les modes laser choisisThe recent advent of wavefront-shaping techniques has demonstrated the ability to control the propagation of light through a broad range of complex media, amongst them multimode fibers. The case of a multimode fiber which is also a gain medium presents increased complexity, since the pump beam, in itself multimode, may act upon the signal light in speckle-like spatial profiles of amplification. The resulting heterogeneous gain may be viewed as analogous to a non-unitary scattering process. Interest in the study of such systems has recently risen in several domains, such as optical communications, high-power fiber lasers, and random lasers. In this work, we consider a multimode fiber doped by a rare-earth element, and pumped by a coherent pump beam that passes through a wave-front shaping scheme, rendering the modal composition of the excitation within the fiber configurable. We explore the possibility of harnessing the degrees of freedom thus offered in the pumping, for controlling the output signal of such a gain system. A theoretical model and its implementation as a numerical solver serve to quantify the degree of achievable control, as well as providing insights into the fundamental mechanisms limiting it. In an amplifier configuration, the experimental work successfully validated the model’s predictions by showing a significant effect of the wave-front shaping of the pump upon the speckle at the amplifier’s output. In the lasing cavity configuration, the experimental work demonstrated the ability of the pump modulation scheme to influence the lasing emission, in particular to favor or suppress chosen lasing modes
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Ruzmetov, Talant A. "THE ROLE OF CHAIN FLEXIBILITY AND CONFORMATIONALDYNAMICS ON INTRINSICALLY DISORDERED PROTEINASSOCIATION". Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1564588247414425.
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Jijie, Roxana. "Synthesis and characterization of complex nano-structures at the interface with biological medium". Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10084/document.
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L’augmentation des infections causées par des pathogènes résistants aux médicaments est devenue un problème de santé majeur dans le monde entier qui impose le développement de nouvelles stratégies destinées à empêcher la formation de biofilms et à éliminer les bactéries. Dans ce contexte, l’objectif de cette thèse a été la préparation de nanostructures complexes pour contrôler l’adhérence des cellules à des surfaces et inactiver les bactéries pathogènes. Ainsi, nous proposons différentes approches qui consistent en l’utilisation de : i) une couche micro-structurée de polystyrène polymérisé à l’aide d’un plasma (pPS), ii) la thérapie photodynamique à base de nanoparticules hybrides activées par un rayon laser dans le proche infrarouge (NIR) et iii) des nanoparticules de carbone fonctionnalisées par l’ampicilline, comme solutions possibles pour éliminer les bactériesThe increase of infections by multi-drug resistant pathogens has become an important worldwide healthcare issue that requires the development of new strategies to prevent biofilm formation and to kill bacteria. In this context, the aim of this thesis was the design of complex nano-structures to control cells adhesion to surfaces and to inactivate pathogenic bacteria. To this end, we propose different strategies relying on the use of i) micro-structured plasma polymerized styrene (pPS) films, ii) particle-based photodynamic therapy combined with a pulsed laser in the near infrared (NIR) region and iii) ampicillin-functionalized, fluorescent carbon dots (CDs) as possible solutions for bacterial killing. Firstly, we performed a detail characterization of pPS films used as substrates to study the behavior of biological systems
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Vazart, Fanny. "Gas-phase formation of Complex Organic Models molecules in interstellar medium: computational investigations". Doctoral thesis, Scuola Normale Superiore, 2017. http://hdl.handle.net/11384/85813.
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[excerpt form the abstract:] In the field of astro- and prebiotic chemistry, the building blocks of life, which are molecules composed of more than 6 atoms, are called Complex Organic Molecules (COMs). Their appearances on the early inorganic Earth is therefore one of the major issues faced by researchers interested in the origin of life. In this thesis, split into three parts, the main purpose is to show how different COMs are formed in interstellar medium (ISM), using computational chemistry.
The first part focuses mainly on preliminary studies aiming at evaluating the appropriate level of theory to use to perform studies of formation reactions. First, a comprehensive benchmark of C≡N stretching vibrations computed at harmonic and anharmonic levels is reported with the goal of proposing and validating a reliable computational strategy to get accurate results for this puzzling vibrational mode, involved in biological molcules, without any ad hoc scaling factor.
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Lam, Chun-kit, e 林晉傑. "The dynamics of wave propagation in an inhomogeneous medium: the complex Ginzburg-Landau model". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40887881.
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Lam, Chun-kit. "The dynamics of wave propagation in an inhomogeneous medium the complex Ginzburg-Landau model /". Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40887881.
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Beveridge, Rebecca. "Mass spectrometry methods for characterising the dynamic behaviour of proteins and protein complexes". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/mass-spectrometry-methods-for-characterising-the-dynamic-behaviour-of-proteins-and-protein-complexes(81961313-2d3e-4ad3-9c6f-6299549e9738).html.
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Research into the relationship between the structure and function of proteins has been ongoing now for several decades. More recently, there has been an explosion in the investigation of the dynamic properties of proteins, and how their dynamic propensity relates to their function. This new direction in protein research requires new techniques to analyse protein dynamics, since most traditional techniques are biased towards a fixed tertiary structure. Mass spectrometry (MS) is emerging as a powerful tool to probe protein dynamics since it can provide information on interconverting conformations and has no preference towards the folded state. Furthermore, its low sample consumption, rapid data acquisition and low data processing positions MS as an attractive tool in protein structure research. The hybrid technique of ion mobility-mass spectrometry provides further insight into the range of conformations adopted by proteins and protein complexes, by providing information on the size in terms of rotationally averaged collision cross section. The work presented in this thesis considers proteins with a range of structural characteristics. We use ion mobility mass spectrometry to investigate proteins of different extents of disorder, protein complexes with dynamic entities and a system that undergoes structural rearrangement upon ligand binding. First, a framework of mass spectrometry experiments is described which allows identification of the extent of structure and disorder within proteins. This framework is tested on a range of different systems throughout the thesis. Differences in the gas-phase properties of two conformationally dynamic proteins which behave similarly in solution are investigated and from this research we postulate a new ionisation mechanism for partially folded proteins. The dynamic propensity of C-terminal p27 is investigated and compared to two permutants which allows us to delineate how the location of charged residues in a primary sequence affects the structure of a protein. We monitor the 'folding-upon-binding' behaviour of p27 upon association with its binding partners, and how this differs with the order of charged residues in the linear sequence. Finally, we describe the structural rearrangement of Fdc1 upon the binding of its cofactor; a prenylated FMN molecule. This thesis demonstrates the suitability of ion mobility-mass spectrometry for the investigation of dynamic properties of proteins and protein complexes.
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Williams, Benjamin Graham. "On the medium-term simulation of sediment transport and morphological evolution in complex coastal areas". Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/6704.
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A program for selecting the optimal wave conditions for morphodynamically accelerated simulations of coastal evolution (‘OPTIWAVE’) has been constructed using a novel Genetic Algorithm approach. The optimization routine iteratively reduces the complexity of an incident wave climate by removing the events that contribute least to a target sediment transport pattern, and then ‘evolving’ a new set of weights for the remaining wave conditions such that the target sediment transport pattern (and magnitude) is optimally maintained. The efficacy of OPTIWAVE to satisfactorily reduce the incident wave climate is tested against three coastal modeling paradigms of increasing complexity: (a) A simple 1-D beach profile model (no tides); (b) A 2-D micro-tidal beach; (c) A tidal inlet, where the interaction between waves, tides, and wave-current interaction, adds significant complexity. The simple test case for a beach profile shows that OPTIWAVE is successfully capable of maintaining a target profile-integrated long-shore sediment transport rate. The calculated skill and RMSE of the reduced wave climate is a good indicator of its ability to reproduce the target sediment transport pattern. The optimal number of wave conditions is identified by an ‘inflection point’ at a critical number of wave conditions, where less complex a wave climate results in substantially reduced skill (increased error). The assumption that the ability of OPTIWAVE to reproduce a target sediment transport field is a valid proxy for the potential skill of a morphologically accelerated simulation is assessed for the case of a 2D micro-tidal beach. The skill of the accelerated models, which use a state-of-the-art ‘event-parallel’ method of simulating bed evolution from multiple wave conditions in parallel, is tested against a ‘brute force’ reference simulation that considers the full wave forcing. A strong positive correlation is found between the skill of the reduced wave climate to reproduce a target sediment transport pattern, and the resultant skill of the accelerated morphodynamic model against the ‘brute force’ reference simulation. Finally, the ability to combine reduced wave and tide climates for simulations that must consider both wave and tidal forcing, is assessed against a ‘brute force’ reference simulation of the seasonal evolution Ancao inlet, Algarve, Portugal. The reference simulation is validated against a comprehensive field dataset collected in 1999, and is shown to qualitatively reproduce key features of inlet behavior over a seasonal period. The combination of reduced wave and tidal climates in accelerated ‘event-parallel’ models did not successfully reproduce the reference seasonal morphological evolution of Ancao inlet. Assessing the model Brier Skill Score showed that the model was more successful in reproducing the reference morphology in areas dominated by tidal forcing, but did not have any predictive power in regions where morphological evolution is due to some combination of both wave and tidal processes.
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Hildebrand, William Kurt. "Ultrasonic waves in strongly scattering disordered media: understanding complex systems through statistics and correlations of multiply scattered acoustic and elastic waves". American Physical Society, 2014. http://hdl.handle.net/1993/30843.
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Ultrasonic wave transport in strongly scattering, disordered media is investigated via analysis of the multiply-scattered transmitted field. Measurements of transverse confinement, statistics, and correlations of the intensity were performed on an aluminum mesoglass, where aluminum beads were brazed together to form a porous slab sample. Comparison of the transverse confinement measurements with the self-consistent theory of localization was used to identify and locate a mobility edge in the sample at f = 1.1011 MHz, enabling a measurement of the critical exponent nu characterizing the Anderson transition, nu ~ 1.6–2. Infinite-range C0 correlations were observed, and observed to grow dramatically near the mobility edge, along with the C2 and C3 correlations. Measurements of the multifractal exponent Delta_2 were able to confirm the link between C0 correlations and Anderson localization. Experiments using the aluminum mesoglass with ethanol-filled pores showed evidence of two nearly-independent propagating modes, one of which appears to be characterized by a strongly renormalized diffusion coefficient. The density of states and level spacing statistics were investigated using a different mesoglass, constructed by sintering glass beads percolated on a random lattice. Direct measurements of these quantities were obtained by cutting small samples of this mesoglass, allowing individual vibrational modes to be resolved. The density of states showed a plateau extending well into the expected Debye regime, and evidence of a Boson peak was observed at low frequencies. The level spacing statistics indicated that transport in the frequency ranges measured was on the diffusive side of the mobility edge, showing agreement with the predictions of the GOE from random matrix theory. The dynamics of a suspension of bubbles were investigated using phase-based Diffusing Acoustic Wave Spectroscopy, where phase correlations were found to give additional information beyond traditional field- and intensity-based correlation measurements.October 2015
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Solana, Mathias. "Electronic transport in spin-glasses and mesoscopic wires : correlations of universal conductance fluctuations in disordered conductors". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAY020/document.
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Le travail expérimental développé pendant cette thèse se situe à l'interface de deux champs en physique de la matière condensée, à savoir les verres de spins et la physique mésoscopique. Les verres de spins ont été largement étudié et font partie des problèmes les plus débattus au cours des années tant d'un point de vue expérimental que théorique. Cet état est caractérisé par des propriétés très particulières qui se font jour lors d'une transition de phase magnétique à très basses températures qui est elle-même inhabituelle. En effet, cette transition est due à un mélange de frustration et de désordre dans la structure magnétique du système. Ce faisant, c'est un système modèle pour les verres et les systèmes frustrés en général. Après bien des efforts, des travaux théoriques ont réussi à décrire l'état fondamental du système au moyen de deux approches différentes et apparemment incompatibles. Cependant, la question de la vraie nature de la phase verre de spin reste grandement débattue.La physique mésoscopique, de son côté, traite du transport électronique dans les échantillons pour lesquels les électrons gardent leur cohérence de phase. Si les électrons restent cohérents, il est possible de voir des effets d'interférences qui sont des signes quantiques de ce qu'il se passe au niveau atomique. Dans cette thèse, il est utilisé pour sonder le désordre aussi bien magnétique que statique dans un verre de spins.Nous montrons que, contrairement à ce qui est cru, de forts changements se déroulent dans le désordre microscopique même à basses températures. Nous prétendons également que ces changements sont purement structuraux et viennent du fait de systèmes dont la distribution en énergie est très largeThe experimental work developed during this PhD is situated at the interface of two fields of condensed matter physics, namely spin glasses and mesoscopic physics. Spin glasses have been widely studied and are one of the problem that has been the most discussed over the years, both on a theoretical and experimental point of view. This state is characterized by very peculiar properties that come to light as it exhibits a magnetic phase transition at low temperatures that is already unusual. Indeed, this transition is due to a mix of frustration and disorder in the magnetic structure of the system, making it an exceptional model system for glasses and frustrated systems in general. After many efforts, theoreticians managed to described the fundamental state of the system by the mean of two different and apparently incompatible approaches. The first one, called RSB theory, is based on a mean-field approximation and predicts a complex phase space with an unconventional hierarchical organization. The second is based on more phenomenological approach and is named Droplet theory. It points towards a unique ground state and explain all the observation by slow relaxation processes. However, the question of the true nature of the spin glass phase is still heavily debated. Mesoscopic physics, for its part, addresses the question of electronic transport for samples in which the electrons keep their phase coherence. If the electrons remains coherent, it is possible to see interference effects that are quantum signs of what happens at the atomic level. In this work, it is used to probe the magnetic and static disorder in spin glasses. Indeed, it is possible to interpret the change in those interferences as changes in the microscopic disorder configuration and to know exactly how the spin glass state evolves. Some work have already tried to use coherent transport in spin glasses but this remains an open field. This work has then be dedicated to the implementation of transport measurement in spin glasses and mesocopic conductors. The first part will be focused on a the experimental setup that was used to perform very precise transport measurements and on the processing of the data taken out of them. In a second part, we will present some general physical characteristics of our samples such as their resistance dependence to the temperature or magnetic field, before extracting the quantum signature in magnetoresistance measurements. Finally, we will discuss the results obtained. We show that strong changes in the microscopic disorder happen even at low temperatures, in opposition to what is believed. We argue that those observed changes are purely structural and come from systems that are widely distributed in energy
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Mutihac, Radu-Christian. "Influence of polar solvents upon the complex formation between crown ethers and cations in nonpolar medium". [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985279761.
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Constantinou, Marios, Michael Gehde e Ronald Dietz. "Emitter - Material – A complex system". Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198230.
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Der Vortrag zeigt die Komplexität der Wechselwirkungen zwischen Infrarotstrahler und Werkstoff beim Infrarotschweißen von Kunststoffen auf. Hierfür werden die Haupteinflüsse auf die Strahler-Werkstoff-Wechselwirkungen beschrieben. Diese sind das Emissionsverhalten des Infrarotstrahlers und das Absorptionsverhalten des Kunststoffs. Der Einfluss der Infrarotstrahlerart (Quarzglasstrahler, Metallfolienstrahler) und von Füllstoffen (Ruß, Glasfasern) im Kunststoff wird näher betrachtet. Zudem enthält der Vortrag eine Empfehlung für die Vorgehensweise beim Infrarotschweißen von Kunststoffen, die Vor- und Nachteile des Fügeverfahrens und einen Einblick in aktuelle Forschungsaktivitäten auf dem Gebiet des Infrarotschweißens von Kunststoffen.
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Rzeszotarski, Jeffrey M. "Uncovering Nuances in Complex Data Through Focus and Context Visualizations". Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/958.
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Across a wide variety of digital devices, users create, consume, and disseminate large quantities of information. While data sometimes look like a spreadsheet or network diagram, more often for everyday users their data look more like an Amazon search page, the line-up for a fantasy football team, or a set of Yelp reviews. However, interpreting these kinds of data remains a difficult task even for experts since they often feature soft or unknown constraints (e.g. ”I want some Thai food, but I also want a good bargain”) across highly multidimensional data (i.e. rating, reviews, popularity, proximity). Existing technology is largely optimized for users with hard criteria and satisfiable constraints, and consumer systems often use representations better suited for browsing than sensemaking. In this thesis I explore ways to support soft constraint decision-making and exploratory data analysis by giving users tools that show fine-grained features of the data while at the same time displaying useful contextual information. I describe approaches for representing collaborative content history and working behavior that reveal both individual and group/dataset level features. Using these approaches, I investigate general visualizations that utilize physics to help even inexperienced users find small and large trends in multivariate data. I describe the transition of physicsbased visualization from the research space into the commercial space through a startup company, and the insights that emerged both from interviews with experts in a wide variety of industries during commercialization and from a comparative lab study. Taking one core use case from commercialization, consumer search, I develop a prototype, Fractal, which helps users explore and apply constraints to Yelp data at a variety of scales by curating and representing individual-, group-, and dataset-level features. Through a user study and theoretical model I consider how the prototype can best aide users throughout the sensemaking process. My dissertation further investigates physics-based approaches for represent multivariate data, and explores how the user’s exploration process itself can help dynamically to refine the search process and visual representation. I demonstrate that selectively representing points using clusters can extend physics-based visualizations across a variety of data scales, and help users make sense of data at scales that might otherwise overload them. My model provides a framework for stitching together a model of user interest and data features, unsupervised clustering, and visual representations for exploratory data visualization. The implications from commercialization are more broad, giving insight into why research in the visualization space is/isn’t adopted by industry, a variety of real-world use cases for multivariate exploratory data analysis, and an index of common data visualization needs in industry.
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Desai, Megha. "Structural and Functional Characterization of the MBD2-NuRD Co-Repressor Complex". VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3617.
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The MBD2-NuRD co-repressor complex is an epigenetic regulator of the developmental silencing of embryonic and fetal β-type globin genes in adult erythroid cells as well as aberrant methylation-dependent silencing of tumor suppressor genes in neoplastic diseases. Biochemical characterization of the MBD2-NuRD complex in chicken erythroid cells identified RbAp46/48, HDAC1/2, MTA1/2/3, p66α/β, Mi2α/β and MBD2 to comprise this multi-protein complex.
In the work presented in Chapter 2, we have pursued biophysical and molecular studies to describe a previously uncharacterized domain of human MBD2 (MBD2IDR). Biophysical analyses show that MBD2IDR is an intrinsically disordered region (IDR). Despite this inherent disorder, MBD2IDR increases the overall binding affinity of MBD2 for methylated DNA. MBD2IDR also recruits the histone deacetylase core components (RbAp48, HDAC2 and MTA2) of NuRD through a critical area of contact requiring two contiguous amino acid residues, Arg286 and Leu287. Mutation of these critical residues abrogates interaction of MBD2 with the histone deacetylase core and impairs the ability of MBD2 to repress the methylated tumor suppressor gene Prostasin in MDA-MB-435 breast cancer cells. These findings expand our knowledge of the multi-dimensional interactions of the MBD2-NuRD complex that govern its function.
In Chapter 3, we have discussed a novel mechanism for MBD2-mediated silencing of the fetal γ-globin gene. Through microarray expression analyses in adult erythroid cells of MBD2-/- mice, we identified ZBTB32 and miR-210 as downstream targets of MBD2. Over-expression of ZBTB32 and miR-210 in adult erythroid cells causes increased expression of the silenced fetal γ-globin gene. Thus, our results indicate that MBD2 may regulate γ-globin gene expression indirectly though ZBTB32 and miR-210 in adult erythroid cells.
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GHEZZI, DANIELE. "Identification and characterization of nuclear genes responsible for human mitochondrial disorders: fastkd2, responsible for a neurological disease associated with cox defiency and sdhaf1, encoding a complex II assembly, mutated in SDH-defective leukoencephalopaty". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2009. http://hdl.handle.net/10281/7657.
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My researches during the DIMET project have been focused on the discovery of new genes responsible for mitochondrial disorders and the characterization of their role.
Recent epidemiological studies show that mitochondrial disorders have an incidence of 1:5000. These disorders are very heterogeneous and hence the diagnosis is difficult. Moreover mitochondrial dysfunctions are now clearly related to a wide range of disease conditions (i.e. neurodegeneration and cancer).
The majority of the inherited mitochondrial disorders, especially those with onset in infancy or childhood, are due to nuclear genes encoding proteins targeted to mitochondria. While identification of mutations in mitochondrial DNA has become relatively easy thank to the feasibility to perform the complete sequence analysis of mtDNA, the analysis of genomic DNA is more complicate and therefore the number of nuclear genes associated with mitochondrial diseases is still small.
Genome-wide analysis in families with autosomal recessive mitochondrial disorders could help to identify a genomic region to be further investigated. However, about one half/one third of the components of the mitochondrial proteome have yet to be identified, and this lack of information makes the search of candidate genes more difficult.
By linkage analysis or homozygosity mapping and prioritization of candidate genes, I studied subjects from multiconsanguineos families characterized by clinical pictures compatible with mitochondrial disorders.
In chapter 2, there is the report regarding the discovery of a nonsense mutation in two brothers displaying asymmetric brain atrophy, psychomotor regression and severe complex IV deficiency. The mutated gene codes for a mitochondrial predicted kinase that may have a role in apoptosis.
Using the same procedure, I take part in a project, which leads to the identification of the first assembly factor for complex II of the OXPHOS system (Chapter 3). Two different mutations were found in two pedigrees, with affected children characterized by acute psychomotor regression followed by spastic quadriparesis and/or dystonia. The pathogenic role of the mutations was confirmed in cellular and yeast models.
Finally, in chapter 4, there is the characterization of a protein, MR-1, already known and responsible for a movement disorder (PNKD, Paroxysmal non kinesigenic Dyskinesia). The mutant isoforms were erroneously localized into cytosol or membranes, whereas I demonstrated that they are mitochondrial and that the mutations reported so far in PNKD patients (and a new mutation identify in our study) are in the mitochondrial targeting signal (MTS). Hence PNKD could be considered a mitochondrial disease, due to a novel mechanism based on a deleterious action of the MTS.
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Sayad, D., C. Zebiri, Issa T. Elfergani, Jonathan Rodriguez, Raed A. Abd-Alhameed e F. Benabdelaziz. "Analysis of Chiral and Achiral Medium Based Coplanar Waveguide Using Improved Full Generalized Exponential Matrix Technique". RadioEngineering, 2020. http://hdl.handle.net/10454/18304.
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YesIn this work, an analytical study of the electromagnetic propagation in a complex medium-based suspended three-layer coplanar waveguide (CPW) is carried out. The study aims at a numerical calculation of the dominant hybrid mode complex propagation constant in the CPW printed on a bianisotropic substrate. The herein considered bianisotropy is characterized by full 3×3 tensors of permittivity, permeability and magnetoelectric parameters. The study is based on the numerical derivation of the Green's functions of such a complex medium in the spectral domain. The study is carried out using the Full Generalized Exponential Matrix Technique based on matrix- shaped compact mathematical formulations. The Spectral Method of Moments (SMoM) and the Galerkin's procedure are used to solve the resulting homogeneous system of equations. The effect of the chiral and achiral bianisotropy on the complex propagation constant is particularly investigated. Goo d agreements with available data for an anisotropic-medium-based suspended CPW structure are achieved. Various cases of chiral and achiral bianisotropy have been investigated, and particularly, the effect on the dispersion characteristics is presented and compared with cases of isotropic and bianisotropic Tellegen media.
FCT/MEC through national funds and when applicable co-financed by the ERDF, under the PT2020 Partnership Agreement under the UID/EEA/50008/2019 project.
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Normandeau, Magdalen. "The Galactic plane survey pilot project, the interstellar medium environment of the w3/w4/w5 star formation complex". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq20761.pdf.
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TESTA, LORENZO. "Conformational transitions of the intrinsically disordered protein sic1 from the yeast saccharomyces cerevisiae. Towards structural and functional characterization of the whibitory complex with CDK1-CLB5". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/43673.
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Many naturally occurring proteins have been shown to lack rigid three-dimensional structure, existing instead as dynamic ensembles of inter-converting conformations. Many of these proteins acquire an ordered structure only upon binding to specific intracellular partners. In isolation, these proteins exhibit a highly dynamic structure that is resembling more the denatured rather than native state of “normal” globular proteins. Intrinsically disordered proteins (IDPs) have attracted a great deal of interest since it became clear that their lack of structural specificity is of physiological importance. Indeed, structural disorder characterizes a broad class of regulatory proteins, which all share the feature to bind multiple interactors. Intrinsic disorder is a common property of many protein types especially among the proteins involved in signal transduction and transcription regulation. The dynamic properties of IDPs are considered to be instrumental to adaptation to different interaction surfaces and to favor rapid formation and dissociation of the complexes, as required for efficient intracellular regulatory networks.
In the yeast Saccharomyces cerevisiae, Sic1 is a central regulatory protein of the cell cycle, acting as inhibitor of the cyclin-dependent protein kinases by forming ternary complexes with kinases and their cognate cyclins. A well established role of Sic1 is to control the timing of entrance in S phase during the yeast cell cycle by inhibiting the complex Cdk1-Clb5/6, whose activity is required for the G1-to-S transition. The inhibition is released upon ubiquitin-dependent Sic1 degradation, which is, in turn, triggered by Sic1 phosphorylation at multiple sites in its N-terminal region. Previous work has shown that Sic1 is disordered in its whole length, with some intrinsic propensity to form ordered helical structure. The Sic1 functional kinase-inhibitor domain (KID) corresponds to the C-terminal 70, out of 284, amino acids forming the native protein. This Sic1 C-terminal region is structurally and functionally related to the mammalian p21 and p27 KIDs that are located, instead, at the protein N-terminus. A detailed structural characterization of the mammalian proteins have been achieved, both on their unbound states and on the complexes with their partners.
Structural characterization of proteins in disordered conformation is technically difficult, but it is important to better understand folding transitions to ordered states. In this work, an in-depth description of Sic1 in the absence of interactors, both in terms of secondary and tertiary structure, is presented. A multiparametric analysis, which employed a set of complementary methods sensitive to distinct structural features, has been used to guarantee the description of such a highly dynamic and heterogeneous molecular ensemble.
First of all, a novel tool for extracting structural information from electrospray-ionization mass spectrometry (ESI-MS) data has been developed. It has been shown that the extent of protein ionization under nondenaturing conditions correlates with the solvent-accessible surface area (SASA), for either folded or unfolded proteins. Therefore, the technique has been employed to estimate the SASA of Sic1.
Fragments corresponding to the N- and C-terminal moieties of Sic1 have been produced, and circular dichroism (CD) data showed that the little content in secondary structure is distributed quite uniformly throughout the chain length, although the C-terminus is slightly more ordered than the N-terminus. Consistent with such evidence, conformational analysis by ESI-MS suggested that the Sic1 C-terminal domain is more structured than its complementary N-terminal domain. Thus, altogether, functional and structural features pointed to a modular organization of this protein, despite its disordered nature.
A more detailed description of the Sic1 KID has been achieved by integrating an array of biophysical data with all-atom molecular dynamics (MD) simulations. Highly dynamic helical elements are detected by Fourier-transformed infrared (FT-IR) spectroscopy, while protein tertiary structure has been probed by nondenaturing gel filtration, ESI-MS, and electrospray-ionization ion-mobility mass-spectrometry (ESI-IM-MS). The molecular ensemble of the isolated KID fragment has been found to interconvert between collapsed states of different compactness, with a small fraction of the population found in a highly compact state. MD simulations results has suggested a predominant role of electrostatic interactions in promoting the compaction in the Sic1 inhibitory domain. Moreover, comparison to the full-length protein hinted to a critical role of chain length in determining the overall compaction of Sic1.
Since no structural data are available for the Sic1-Cdk1-Clb5/6 ternary complex, the molecular mechanism by which Sic1 inhibits S-Cdk1 activity remains unclear. In this work, the results about the heterologous expression and purification of Cdk1 and Clb5 are also presented. Cdk1 has been overexpressed as a histidine-tagged protein in Escherichia coli cells and CD analysis has revealed a similar fold to mammalian homologues. The full-length Clb5, on the contrary, underwent proteolytic degradation when expressed in E. coli cells, probably because of the high degree of disorder in the N-terminal region of the amino-acids sequence. The deletion of the first 156 residues has allowed the expression of the protein as inclusion bodies (IBs). A purification procedure has been then developed, so that IBs have been solubilized and refolded by on-column removal of denaturing conditions. The results concerning the expression and the characterization of Cdk1 and Clb5 represent a starting points for the production of a functional Cdk1-Clb5 complex and so, ultimately, for the complete description of Sic1 binding mechanism.
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Oktar, Ceren. "Comparative Analysis Of Product And By-product Distributions In Defined And Complex Media In Serine Alkaline Protease Production By Recombinant Bacillus Subtilis". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1262880/index.pdf.
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In this study, firstly the effects of aspartic acid group amino acids -which were reported to be the potential bottleneck in serine alkaline protease (SAP) synthesis- on SAP production were investigated by substituting at a concentration range of 0-15 mM by using recombinant Bacillus subtilis carrying pHV1434::subC gene. All aspartic acid group amino acids except threonine inhibited SAP activity when CAA≥
2.5 mM. The highest SAP activities with asparagine, aspartic acid, lysine, threonine, isoleucine and methionine werefound to be 1.89-, 1.87-, 1.61-, 1.48-, 1.4-, and 1.4-fold higher than the reference medium activity, respectively, when the concentration of each amino acid was CAA=0.25 mM. The product and by-product distributions in defined and complex media in SAP production were also analyzed and compared in order to obtain a depth in-sight on functioning of the metabolic reaction network. The highest SAP activity in complex medium was found to be 3&ndash
fold higher than defined medium activity, while, specific SAP production rate was 1.2- fold higher. The highest cell concentration in complex medium (CX= 14.3 g/dm-3) was 8.1-fold higher than that obtained in defined medium (CX= 1.75 g/dm-3). In both media, oxaloacetic acid was observed extracellularly and intracellularly. In complex medium there was also succinic acid in the extracellular medium indicating that the operation of TCA cycle was insufficient. In both media serine, valine and glycine were observed neither in the extracellular nor in the intracellular media indicating that the synthesis of these amino acids can be a secondary rate limiting step. In defined medium asparagine was present neither in the cell nor in fermentation broth whereas, methionine was observed in the cell in high amounts, probably due to the lower flux values towards asparagine. Thus, in defined medium the synthesis of asparagine can also be a potential bottleneck in SAP production in defined medium.
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Losquin, Arthur. "Surface Plasmon modes revealed by fast electron based spectroscopies : from simple model to complex". Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00919765.
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Surface Plasmons (SP) are elementary excitations mixing electrons and photons at metal surfaces,which can be seen in a classical electrodynamics framework as electromagnetic surface eigenmodesof a metal-dielectric system. The present work bases on the ability of mapping SP eigenmodes withnanometric spatial resolution over a broad spectral range using spatially resolved fast electron basedspectroscopies in a Scanning Transmission Electron Microscope (STEM). Such an ability has beenseparately demonstrated during the last few years by many spatially resolved experiments of ElectronEnergy Loss Spectroscopy (EELS), which measures the energy lost by fast electrons interactingwith the sample, and CathodoLuminescence (CL), which measures the energy released by subsequentlyemitted photons. In the case of EELS, the experimental results are today well accountedfor by strong theory elements which tend to show that the quantity measured in an experiment canbe safely interpreted in terms of the surface eigenmodes of the sample. In order to broaden thisinterpretation to fast electron based spectroscopies in general, I have performed combined spatiallyresolved EELS and CL experiments on a simple single nanoparticle (a gold nanoprism). I have shownthat EELS and CL results bear strong similarities but also slight differences, which is confirmed bynumerical simulations. I have extended the theoretical analysis of EELS to CL to show that CLmaps equally well than EELS the radiative surface eigenmodes, yet with slightly different spectralfeatures. This work is a proof of principle clarifiying the quantities measured in EELS and CL,which are shown to be respectively some nanometric equivalent of extinction and scattering spectroscopieswhen applied to metal-dielectric systems. Based on this interpretation, I have applied EELSto reveal the SP eigenmodes of random metallic media (in our case, semicontinuous metal films beforethe percolation threshold). These SP eigenmodes constitute a long standing issue in nanooptics.I have directly identified the eigenmodes from measurements and data processing. I havefully characterized these eigenmodes experimentally through an electric field intensity pattern, aneigenenergy and a relaxation rate. Doing so, I have shown that the fractal geometry of the medium,which grows towards the percolation, induces random-like eigenmodes in the system at low energies.Keywords: Surface plasmons, fast electron based spectroscopies, scanning transmission electronmicroscopy, disordered media
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Chevalier, Franck. "Influence of medium components on complex carbohydrates structures : the examples of two relevant carbohydrate moieties found on glycoproteins heparin and GPI-anchor". Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE10120.
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Les glycoprotéines et les protéoglycanes sont impliqués dans de nombreux phénomènes biologiques qui peuvent être régulés par les carbohydratzs attachés à la chaîne protéique après traduction. La structure et la dynamique de ces modifications post-traductionnelle dépendent des interactions avec d'autres molécules présentes dans le même milieu. L'effet de ces interactions sur la structure est souvent négligé et les molécules sont souvent étudiées à l'état isolé. L'influence de ces interactions a été étudié au travers des deux exemples : l'héparine et les ancres GPI. L'influence de ces interactions a été étudié au travers de deux exemples : l'héparine et les ancres GPI. L'influence du patron de sulfatation de l'héparine sur l'interaction avec des contre ions ainsi que l'ancrage d'un GPI dans une micelle ont été étudiées par RMN et ModellingGlycoproteins and proteoglycans are involved in various phenomena which could be regulated by the carbohydrates chains linked after translation to the core protein. Structure and dynamics of these modifications depend on the interactions with take place with others molecules present in the same milieu. Their effect on the structure is sometimes neglected and molecules are often studied as isolated and pure. The influence of these interactions has been put under focus through two different examples : heparin and GPI anchor. The influence of the sulphation pattern of heparin on their interaction with counter ions and the anchorage of a GPI into a micelle have been studied by NMR spectroscopy and Modelling
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Lima, Gilson Francisco de. ""Caminhadas determinísticas em meios desordenados: problema da caminhada do turista"". Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-24052006-144856/.
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O estudo de caminhadas aleatórias em meios desordenados e um assunto bastante explorado e pode modelar uma grande variedade de problemas, como por exemplo, problemas de transporte (difusão). O estudo de caminhadas determinísticas em meios desordenados é um assunto pouco explorado. Em uma paisagem composta de N sítios distribuídos aleatoriamente no espaço, um caminhante ("turista") visita estes sítios seguindo a seguinte regra determinística: ir para o sítio vizinho mais próximo que não tenha sido visitado nos últimos passos. De cada sítio inicial, a trajetória obtida com esta dinâmica determinística apresenta inicialmente um tempo de transiente t, onde novos sítios são visitados, e no final um atrator de período p, onde os mesmos sítios são sempre revisitados. Apesar da simplicidade do modelo, a dinâmica e complexa e os resultados não são triviais. Para dimensionalidades d = 2, a distribuição de atratores de período p, obtida numericamente, pode ser descrita por uma lei de potência com um corte exponencial. Os modelos de ligações aleatórias simétricas (que representa o limite de alta dimensionalidade d = 1 do modelo proposto) e assimétricas indicam que o corte exponencial se torna menos importante à medida que N aumenta. O expoente da lei de potência independe da memória tau, sendo portanto uma distribuição robusta. A dinâmica do turista pode ser aplicada a problemas mais abstratos, onde apenas relações de ordem entre vizinhos são dados. O estudo (por amostragem) da estrutura de um dicionário de sinônimos e um exemplo que foi considerado. Mostrou-se que as palavras podem ser embebidas em um espaço Euclidiano de baixa dimensionalidade.Este resultado concorda com um recente estudo exaustivo realizado e questiona o modelo de análise semântica latente. Com a finalidade de entender a transição entre uma caminhada determinística e uma caminhada aleatória, generalizou-se o problema com memória nula designando uma distribuição de probabilidades para o turista visitar os diversos sítios. Esta distribuição e parametrizada por uma variável externa T (temperatura) de modo que para T = 0 têm-se a caminhada do turista como caso limite e para T tendendo para infinito todos os sítios são visitados com igual probabilidade. Resultados analíticos (d = 1) e numéricos mostram a existência de uma região bem delimitada de transição entre os regimes não-ergódico (baixa temperatura) e ergódico (alta temperatura). Uma analogia é estabelecida com o modelo de vidros de Bouchaud. A eficiência da caminhada com relação aos novos sítios visitados, foi estudada e ela e máxima na borda da aleatoriedade, ou seja, ao redor da temperatura de transição.The study of random walks in disordered media is one well-developed subject and it can model a great variety of problems, for instance, problems of transport (diffusion). The study of deterministic walks in disordered media is a subject not too explored. In a landscape composed of N sites randomly distributed in of, a walker ("tourist") visits these sites following the deterministic rule: going to the nearest site that has not been visited in the last tau steps. From each initial site, the trajectory, obtained with this deterministic dynamics, presents initially a time transient t, where new sites are visited, and, in the end, a p-period attractor, where the same sites are always revisited. In spite of the simplicity of the model, the dynamics is complex and the results are not trivial. For dimensionalities d = 2, the distribution of p-period obtained numerically can be described by a power law with an exponential cut. The models of symmetrical random connections (that represents the limit of high dimensionality d = 1 of the proposed model) and asymmetrical random connections indicate that the exponential cut turns out to be less important as N increases. The exponent law of the power law does not depend on the memory tau, being therefore a robust distribution. The tourist dynamics can be applied to more abstract problems, where just relationships of neighbor order are given. The study (by sampling) of the structure of a dictionary of synonyms has been considered. It has been shown that the words can be embedded in an Euclidean space of low dimensionality. This result agrees with a recent exhaustive study accomplished and it challenges the model of latent semantic analysis. With the purpose of understanding the transition between a deterministic and a random walk a generalization of the problem, with null memory has been performed by designating a distribution of probabilities for the tourist to visit the several sites. This distribution has the external variable T (temperature) as a parameter so that, when T = 0 it has the tourist walk as a limiting case and for T tending to infinity all of the sites are visited ith equal probability. Analytical numerical results (d = 1) show the existence of well delimited transition between non-ergodic (low temperature) and ergodic (high temperature) regime. An analogy is established Bouchaud glass model. The walk efficiency, regarding the new visited sites to trajectory length, has been studied and it is maximum at the edge of stochasticity, in other words, around the temperature of transition.
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Downey, Debora Ann. "The effectiveness of AAC training protocols for acute care Nurses: a randomized controlled trial of an instructional on-line medium for clinical skills teaching". Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/4616.
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Acutely ill patients, across the age continuum, often present with complex communication needs (CCN) due to motor, sensory, cognitive and linguistic barriers they may experience during their hospital encounter. While hospital administrators recognize the importance of improving communication among the healthcare team members to increase quality and safety measures, few have focused on improving the patient-provider communication process, especially for patients with CCN. Recent Joint Commission standards mandates hospitals and healthcare providers improve communication for patients with CCN across all points of the care continuum. The study investigated the effectiveness of AAC training protocols for acute care nurses and ancillary healthcare providers using an on-line instructional medium for clinical skills teaching. The study design allowed for the measurement of learning following exposure to the tutorial and the analysis of possible clinical skill application. The current study invited a total of 377 nurses and graduate students to participate. Eight-three participated in the study and were divided randomly into two groups. Seventeen (20.5%) were assigned to in the control group, and 66 (79.5%) participants were into the test group. Both groups were directed to complete a pre-test measure. This was followed by exposure to the tutorial for the test group. The groups then were instructed to complete a post-test measure. For all participants in the test condition, the mean difference score (post-pre) was 19.2. The average pre-test score was 60.8 with a standard deviation of 12.4 while the average post-test score was 80.1 with a standard deviation of 11.3. This difference was significant (p
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Robbins, James F. (James Franklin). "Critical examination of a complex and critical major acquisition for the Department of Defense : the advanced medium range air-to-air missle (AMRAAM)". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12100.
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Pérez, Cesaretti Mauricio David <1980>. "General effective medium model for the complex permittivity extraction with an open-ended coaxial probe in presence of a multilayer material under test". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4479/1/Mauricio_Perez_PhD_Thesis_Final.pdf.
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The work presented in this thesis is focused on the open-ended coaxial-probe frequency-domain reflectometry technique for complex permittivity measurement at microwave frequencies of dispersive dielectric multilayer materials. An effective dielectric model is introduced and validated to extend the applicability of this technique to multilayer materials in on-line system context. In addition, the thesis presents: 1) a numerical study regarding the imperfectness of the contact at the probe-material interface, 2) a review of the available models and techniques, 3) a new classification of the extraction schemes with guidelines on how they can be used to improve the overall performance of the probe according to the problem requirements.
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Pérez, Cesaretti Mauricio David <1980>. "General effective medium model for the complex permittivity extraction with an open-ended coaxial probe in presence of a multilayer material under test". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4479/.
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The work presented in this thesis is focused on the open-ended coaxial-probe frequency-domain reflectometry technique for complex permittivity measurement at microwave frequencies of dispersive dielectric multilayer materials. An effective dielectric model is introduced and validated to extend the applicability of this technique to multilayer materials in on-line system context. In addition, the thesis presents: 1) a numerical study regarding the imperfectness of the contact at the probe-material interface, 2) a review of the available models and techniques, 3) a new classification of the extraction schemes with guidelines on how they can be used to improve the overall performance of the probe according to the problem requirements.
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PERON, ANGELA. "TUBEROUS SCLEROSIS COMPLEX: IDENTIFICATION OF THE GENETIC CAUSE IN PATIENTS WITH NO MUTATION DETECTED, AND ANALYSIS OF MOSAICISM". Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/885842.
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Tuberous sclerosis complex (TSC) is an autosomal dominant multisystem disorder characterized by development of hamartomas, intellectual disability, seizures and autism. TSC is caused by inactivating mutations in either the TSC1 or the TSC2 genes. A pathogenic variant is not identified in up to 10% of the patients with a clinical diagnosis of TSC despite full molecular assessment. These individuals are referred to as NMI (No Mutation Identified), and it is not clear if they should be monitored and/or treated in similar fashion to those with known etiology of TSC.
To identify the genetic cause of TSC in these patients, we selected ten individuals with a definite clinical diagnosis of TSC and NMI and performed a pilot study. Three different technologies were used and their results were compared: chromosomal microarray, trio whole genome sequencing, and targeted deep-coverage next generation sequencing of TSC1 and TSC2. We identified mosaic variants in TSC1/TSC2 in six patients. No variants in other genes were detected in the remaining individuals.
Based on the results of the pilot study and on recent literature, we then performed targeted deep-coverage TSC1/TSC2 sequencing on 200 affected individuals using peripheral blood DNA and saliva or other tissue samples where available. We identified 24 patients with mosaic pathogenic variants in TSC1 (n=2) or TSC2 (n=22), defining a rate of mosaicism of 12%. Mosaic variant allele frequency (VAF) ranged from 2% to 32% in blood and from 2% to 35% in saliva. Most affected individuals had low-level mosaicism (VAF ≤10%). We performed an extensive analysis of the phenotype, and show that individuals with a mosaic variant in TSC1/TSC2 often display normal cognitive functioning, although other TSC-associated neuropsychiatric disorders (TAND) are seen in 62% of the patients. Cortical tubers are invariably present and seizures are diagnosed in 54% of the cohort, but infantile spasms are rare. The number of cutaneous manifestations in these patients is often insufficient to meet diagnostic criteria, except for facial angiofibromas. We observed a high frequency of pulmonary and renal manifestations in our mosaic cohort, which are as severe as those seen in the general TSC population. None of the patients who have reproduced transmitted the variant to their offspring.
In conclusion, our study shows that genome sequencing fails to identify rare variants in new genes related to TSC, and a third gene is therefore unlikely to exist. We demonstrated that at least one out of 10 patients with a clinical diagnosis of TSC carries a mosaic pathogenic variant in TSC1 or TSC2. We also showed that individuals with mosaic variants have a distinctive phenotypic severity, with important implications for surveillance.
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Daniliauskienė, Rasa. "Kompleksinės specialiosios pagalbos modelis integruotai ugdant sutrikusios klausos vaikus". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080929_110607-39745.
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Neįgaliųjų integracija visuomenėje suvokiamas kaip natūralus ir negrįžtamas reiškinys. Bendrojo lavinimo mokyklose integruotai ugdomų specialiųjų poreikių turinčių mokinių dalis rodo švietimo prieinamumo, sutrikusios klausos vaikams, užtikrinimo laipsnį bei sąlygų socialinei jų integracijai sudarymą. Sėkmingesnį specialiųjų poreikių vaikų integracijos procesą užtikrina mokytojų pasirengimas ugdyti įvairaus amžiaus specialiųjų poreikių vaikus, bei sėkmingas specialistų, ugdymo įstaigų, tėvų ir vaikų bendradarbiavimas.
Šiame darbe pristatomas sutrikusios klausos vaikų integruoto ugdymo specifiškumas. Integruotas ugdymas dažnai suprantama tik kaip formalus sutrikusios klausos vaikų perkėlimas iš vienos įstaigos į kitą nesuteikiant kvalifikuotos specialistų pagalbos. Nepakankamas dėmesys ugdant sutrikusios klausos vaikus bendrojo lavinimo mokykloje sudaro šio darbo problemą. Šis darbas leis atskleisti kompleksinės specialiosios pagalbos svarbą integruotai ugdant sutrikusios klausos vaikus .
Šio darbo tyrimo tikslas – pateikti kompleksinės specialiosios pagalbos modelį integruotai ugdant sutrikusios klausos vaikus.
Tikslui pasiekti buvo įgyvendinti uždaviniai: apibūdinti klausos sutrikimai ir jų įtaka kalbos ir kalbėjimo raidai, apžvelgti teisiniai dokumentai reglamentuojantys integruotą sutrikusios klausos vaikų ugdymą, išryškintas integruoto ugdymo specifiškumas, sukurtas ir pateiktas kompleksinės specialiosios pagalbos modelis integruotam sutrikusios klausos vaikų ugdymui... [toliau žr. visą tekstą]The integration of the disabled to the society is understood as a natural and irreversible phenomenon. A part of pupils with special needs educated integrally at comprehensive schools shows the availability of education to children with disordered hearing, a degree of the guarantee and creating conditions for their social integration. A more successful integration process for children with special needs is ensured by the teachers’ preparation to educate with special needs of different age and successful communication among specialists, educative institutions, parents and children. In this work the specificity of the integrated educating children with disordered hearing is presented. The integrated education is often understood as formal transferring children with disordered hearing from one institution to another without giving qualified help by specialists. An insufficient attention by educating children with disordered hearing at a comprehensive school makes the problem of this work. This work allows revealing the importance of complex special help by integrally educating children with disordered hearing. The purpose of the research of this work is to give model of complex special help by integrally educating with disordered hearing. These tasks were fulfilled to reach this purpose: disorders of hearingand their influence on the development of language and speaking were defined, juridical documents to regulate the integrated educating children with disordered hearing... [to full text]
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Barroca, Neto ?lvaro. "Simula??o de fluxo de fluidos em meios porosos desordenados uma an?lise de efeito de escala na estimativa da permeabilidade e do coeficiente de arrasto". Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13015.
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Previous issue date: 2012-02-29The present study provides a methodology that gives a predictive character the computer simulations based on detailed models of the geometry of a porous medium. We using the software FLUENT to investigate the flow of a viscous Newtonian fluid through a random fractal medium which simplifies a two-dimensional disordered porous medium representing a petroleum reservoir. This fractal model is formed by obstacles of various sizes, whose size distribution function follows a power law where exponent is defined as the fractal dimension of fractionation Dff of the model characterizing the process of fragmentation these obstacles. They are randomly disposed in a rectangular channel. The modeling process incorporates modern concepts, scaling laws, to analyze the influence of heterogeneity found in the fields of the porosity and of the permeability in such a way as to characterize the medium in terms of their fractal properties. This procedure allows numerically analyze the measurements of permeability k and the drag coefficient Cd proposed relationships, like power law, for these properties on various modeling schemes. The purpose of this research is to study the variability provided by these heterogeneities where the velocity field and other details of viscous fluid dynamics are obtained by solving numerically the continuity and Navier-Stokes equations at pore level and observe how the fractal dimension of fractionation of the model can affect their hydrodynamic properties. This study were considered two classes of models, models with constant porosity, MPC, and models with varying porosity, MPV. The results have allowed us to find numerical relationship between the permeability, drag coefficient and the fractal dimension of fractionation of the medium. Based on these numerical results we have proposed scaling relations and algebraic expressions involving the relevant parameters of the phenomenon. In this study analytical equations were determined for Dff depending on the geometrical parameters of the models. We also found a relation between the permeability and the drag coefficient which is inversely proportional to one another. As for the difference in behavior it is most striking in the classes of models MPV. That is, the fact that the porosity vary in these models is an additional factor that plays a significant role in flow analysis. Finally, the results proved satisfactory and consistent, which demonstrates the effectiveness of the referred methodology for all applications analyzed in this study.
O presente trabalho proporciona uma metodologia que d? um car?ter preditivo ?s simula??es computacionais baseadas em modelos detalhados da geometria porosa de um meio. N?s utilizando o software FLUENT para investigar o escoamento de um fluido newtoniano viscoso atrav?s de um meio fractal aleat?rio que simplifica um meio poroso desordenado bidimensional representando um reservat?rio de petr?leo. Este modelo fractal ? formado por obst?culos de diversos tamanhos, cuja fun??o de distribui??o segue uma lei de pot?ncia, onde o expoente ? definido como sendo a dimens?o fractal de fracionamento Dff do modelo e caracteriza o processo de fragmenta??o desses obst?culos. Eles s?o aleatoriamente dispostos em um canal retangular. O processo de modelagem incorpora conceitos modernos, leis de escala, para analisar a influ?ncia das heterogeneidades encontradas nos campos da porosidade e da permeabilidade de tal maneira que se possa caracterizar o meio em fun??o de suas propriedades fractais. Este procedimento permite analisar numericamente as medidas da permeabilidade k e do coeficiente de arrasto Cd propondo rela??es, tipo lei de pot?ncia, para essas propriedades sobre v?rios esquemas de modelagem. O prop?sito desta pesquisa ? estudar a variabilidade proporcionada por estas heterogeneidades onde o campo de velocidade e outros detalhes da din?mica dos fluidos viscosos s?o obtidos resolvendo numericamente as equa??es da continuidade e de Navier-Stokes no n?vel de poros e observar como a dimens?o fractal de fracionamento do modelo pode afetar as suas propriedades hidrodin?micas. Neste estudo foram consideradas duas classes de modelos, modelos com porosidade constante, MPC, e modelos com porosidade vari?vel, MPV. Os resultados permitiram-nos encontrar rela??es num?ricas entre a permeabilidade, coeficiente de arrasto e os par?metros geom?tricos do modelo. Com base nestes resultados num?ricos propusemos rela??es de escala envolvendo os par?metros relevantes do fen?meno. Nesta pesquisa foram determinadas equa??es anal?ticas para Dff em fun??o dos par?metros geom?tricos dos modelos. Constatamos tamb?m uma rela??o entre a permeabilidade e o coeficiente de arrasto onde uma ? inversamente proporcional ? outra. Quanto ? diferen?a de comportamento ela ? mais marcante nas classes de modelos MPV. Isto ?, o fato da porosidade variar nestes modelos constitui um fator adicional que desempenha um papel significativo na an?lise de fluxo. Finalmente, os resultados encontrados se mostraram consistentes e satisfat?rios, o que demonstra a efic?cia da referida metodologia para todas as aplica??es analisadas nesta pesquisa.
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Leto, P., Courtney Trigilio, Lidia M. Oskinova, Richard Ignace, C. S. Buemi, G. Umana, A. Ingallinera et al. "A Combined Multiwavelength VLA/ALMA/Chandra Study Unveils the Complex Magnetosphere of the B-Type Star HR5907". Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/2682.
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We present new radio/millimeter measurements of the hot magnetic star HR 5907 obtained with the VLA and ALMA interferometers. We find that HR 5907 is the most radio luminous early type star in the cm–mm band among those presently known. Its multi-wavelength radio light curves are strongly variable with an amplitude that increases with radio frequency. The radio emission can be explained by the populations of the non-thermal electrons accelerated in the current sheets on the outer border of the magnetosphere of this fast-rotating magnetic star. We classify HR 5907 as another member of the growing class of strongly magnetic fast-rotating hot stars where the gyro-synchrotron emission mechanism efficiently operates in their magnetospheres. The new radio observations of HR 5907 are combined with archival X-ray data to study the physical condition of its magnetosphere. The X-ray spectra of HR 5907 show tentative evidence for the presence of non-thermal spectral component. We suggest that non-thermal X-rays originate a stellar X-ray aurora due to streams of non-thermal electrons impacting on the stellar surface. Taking advantage of the relation between the spectral indices of the X-ray power-law spectrum and the non-thermal electron energy distributions, we perform 3-D modelling of the radio emission for HR 5907. The wavelength-dependent radio light curves probe magnetospheric layers at different heights above the stellar surface. A detailed comparison between simulated and observed radio light curves leads us to conclude that the stellar magnetic field of HR 5907 is likely non-dipolar, providing further indirect evidence of the complex magnetic field topology of HR 5907.
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Pei, Hongxia. "Bead Modeling of Transport Properties of Macromolecules in Free Solution and in a Gel". Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/chemistry_diss/49.
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On the bead modeling methodology, or BMM, a macromolecule is modeled as a rigid, non-overlapping bead array with arbitrary radii. The BMM approach was pioneered by Kirkwood and coworkers (Kirkwood, J.G., Macromolecules, E.P. Auer (Ed.), Gordon and Breach, New York, 1967; Kirkwood, J.G., Riseman, J., J. Chem. Phys., 1948, 16, 565) and applied to such transport properties as diffusion, sedimentation, and viscosity. With the availability of computers, a number of investigators extended the work to account for the detailed shape of biomolecules in the 1970s. A principle objective of my research has been to apply the BMM approach to more complex transport phenomena such as transport in a gel, electrophoresis (free solution and in a gel), and also transport in more complex media (such as the viscosity of alkanes and benzene). Variables considered by the BMM include the number of beads (N), the radii of the beads, net charge and charge distribution, conformations, salt type, and salt concentration. The BMM has been extended to: (1) account for the existence of a gel; (2) characterize the charge and secondary structure of macromolecules; (3) account more accurately for hydrodynamic interaction (remove the orientationnal preaveraging approximation of hydrodynamic interaction); (4) study the effect of ion relaxation for particles in arbitrary size, shape, and charge; (5) consider the salt dependence of electrokinetic properties; (6) account for the formation of possible complex between guest ions and BGE ions. We also did diffusion constant measurement by NMR for amino acids and short peptides in 10%D2O-90% H2O at room temperature and applied to our modeling study by BMM.
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Sharma, Dhruv. "Macroeconomic agent-based models : a statistical physics perspective". Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLE011.
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Les modèles à agents (Agent-Based Models ou ABMs) sont apparus comme un paradigme complémentaire pour la modélisation des phénomènes macro-économiques. Par rapport à d’autres modèles plus établis, tels que les modelés DSGE (Dynamic Stochastic General Equilibrium), les ABMs offrent un cadre flexible pour comprendre la complexité de la macroéconomie tout en prenant en compte la nature hétérogène des acteurs économiques, des institutions et des marchés, sans faire d’hypothèses trop restrictives. Ces modelés adoptent une approche “bottom-up” de la modélisation macro-économique en simulant le comportement de chaque agent individuel dans l’économie puis en s’agrégeant pour révéler des phénomènes émergents tels que les cycles économiques endogènes ou les crashs soudains. L’objet de cette thèse est de faire progresser une méthodologie communément utilisée en physique statistique et de l’appliquer à l’étude de deux modèles macro-économiques. Dans les deux modèles étudiés ici, nous déterminons d’abord le “diagramme de phase” du modèle pour identifier les régimes macroscopiques pertinents afin de développer une compréhension intuitive de la macro-dynamique en n’utilisant qu’un petit sous-ensemble de paramètres. Le premier modèle présenté ici s’appuie sur le paradigme des problèmes de satisfaction des contraintes (de l’anglais Constraint Satisfaction Problems, CSPs) et l’intègre dans le cadre des règles de comportement du modèle via les contraintes budgétaires des agents. Ces contraintes, similaires à celles du perceptron, un CSP bien-etudié, révèlent l’existence de trois régimes et soulignent l’importance de la dette pour la stabilité macro-économique : à un faible niveau d’endettement, l’économie reste sans structure et les faillites sont fréquentes, alors qu’à un niveau élevé la dette conduit à des cycles économiques endogènes. Entre ces deux extrêmes, l’on trouve un régime intermédiaire de stabilité relative avec de faibles niveaux des faillites tout le temps. Dans ce modèle, les préférences des agents, qui sont à l’origine du désordre dans le CSP, évoluent continuellement dans le temps. Nous étudions donc un schéma dynamique simple pour le perceptron et découvrons qu’un paysage rugueux peut en effet exister avec un désordre dynamique. Enfin, nous généralisons l’ABM Mark-0 pour simuler les chocs exogènes de consommation et de productivité dus à la pandémie de COVID. Alors que les approches standards élaborent un modèle pour comprendre un résultat particulier, ce modèle peut générer une variété de scénarios après un choc de type COVID. En outre, nous étudions également l’efficacité de plusieurs politiques, notamment la très controversée “monnaie hélicoptère”, pour éviter l’effondrement économique. Nous insistons donc sur l’importance des ABMs comme des “générateurs de scénarios” polyvalents, pour produire des résultats difficiles à prévoir en raison de la complexité intrinsèque de la dynamique macro-économiqueAgent-based models (ABMs) have emerged as a complementary paradigm for modeling macroeconomic phenomena. Compared to other, more established models such as DSGE (Dynamic Stochastic General Equilibrium) models, ABMs provide a flexible framework for understanding the complexity of the macroeconomy while at the same time taking into account the heterogeneous nature of economic actors, institutions and markets without making overly restrictive assumptions. ABMs take a “bottom-up” approach towards macroeconomic modeling by simulating the behavior of each individual agent in the economy and then aggregating to reveal emergent phenomena such as endogenous business cycles or flash crashes. The object of this thesis is to advance a methodology commonly used in statistical physics and apply it to the study of two macroeconomic agent-based models. In both models studied here, we first determine the “phase-diagram” of the model to identify the relevant macroscopic regimes to develop an intuitive understanding of the macro-dynamics using a small subset of parameters. The first ABM presented here builds upon the paradigm of constraint satisfaction problems (CSPs) and integrates it within the model’s behavioral rules via agents’ budgetary constraints. These constraints, similar to the well-studied perceptron CSP, reveal the existence of three regimes and underscore the importance of debt for macroeconomic stability: at lowlevels of debt, the economy remains structure-less with frequent bankruptcies while high debt leads to endogenous business cycles. Between these two extremes, an intermediate regime of relative stability is found with low levels of bankruptcies for all times. Within this ABM, agents’ preferences, serving as the source of disorder in the CSP, evolve continuously in time. We thus study a simple dynamical scheme for the perceptron and discover that a rugged landscape can indeed exist with dynamic, annealed disorder. Finally, we extend the Mark-0 ABM to simulate exogenous consumption and productivity shocks due to the Covid pandemic. Whereas standard approaches design a model to understand a particular outcome, this model can generate a variety of scenarios after a Covid-like shock. Furthermore, we also investigate the efficacy of several policies, including the much-debated “helicopter money” drop, in avoiding economic collapse. We thus highlight the importance of ABMs as multi-purpose “scenario generators”, for producing outcomes that are difficult to foresee due to the intrinsic complexity of macro-economic dynamics
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Di, Scala Nicolas. "TRANSITION DE DÉPIÉGEAGE DANS LES RÉSEAUX DE VORTEX SUPRACONDUCTEURS : ÉTUDE PAR SIMULATION NUMÉRIQUE". Phd thesis, Université François Rabelais - Tours, 2012. http://tel.archives-ouvertes.fr/tel-00741545.
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Cette étude traite du dépiégeage et de la dynamique des systèmes élastiques désordonnés. Ce cadre regroupe une large classe de systèmes allant des interfaces (telles que les parois de domaines dans les systèmes magnétiques ou ferroélectriques) aux systèmes périodiques (comme les réseaux de vortex dans les supraconducteur de type II, les colloïdes ou encore les cristaux de Wigner). Dans ces systèmes, la compétition entre l'élasticité de la structure qui veut imposer un ordre parfait et le désordre induit une grande richesse dans le diagramme de phase. L'étude est menée par simulations numériques à grande échelle, dans lesquelles nous nous intéresserons spéci fiquement aux réseaux 2D de vortex supraconducteurs. Deux types de dépiégeage sont observés lorsque l'on met en mouvement ces réseaux à l'aide d'une force extérieure : un dépiégeage plastique et un dépiégeage élastique. Nous portons notre attention sur la transition de dépiégeage élastique obtenue dans le cas d'un piégeage faible. A travers une analyse en loi d'échelle à température nulle et à température nie nous montrons le caractère continu de la transition. Divers exposants critiques sont déterminés dont l'exposant et caractérisant la dépendance en force et en température de la vitesse ou bien l'exposant caractérisant la divergence de la longueur de corrélation du système. Un modèle visco-élastique simple permettant de décrire la plasticité dans les systèmes périodiques évoluant sur un potentiel de piégeage en présence de désordre fort est également développé. Une grande variété de comportements dynamiques, similaires à ceux observés à plus grande échelle dans des systèmes périodiques, peuvent être extraits d'un tel modèle. Un dépiégeage élastique ou plastique est observé, de l'hystérésis est mesurée dans le cas du dépiégeage élastique, et du chaos est détecté pour le dépiégeage plastique.
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Pokhrel, Chandra Prasad. "Crystal growth and charge carrier transport in liquid crystals and other novel organic semiconductors". [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1254234736.
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Thesis (Ph.D.)--Kent State University, 2009.Title from PDF t.p. (viewed April 1, 2010). Advisor: Brett Ellman. Keywords: Laser; Charge generation; Charge transport; Mobility; Trapping; Space charge; Hopping; Tunneling; Lattice vibration; Exciton; Polaron; HUMO; LUMO; Action Spectrum; Quantum efficiency; Crystal Growth; Liquid crystal; Disordered medium. Includes bibliographical references.
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Li, Han [Verfasser], Fritz E. [Akademischer Betreuer] Kühn, Fritz E. [Gutachter] Kühn e Hao [Gutachter] Guo. "Heteroleptic Fe(II)-Hexa-NHC complex with 130 ps MLCT lifetime & Mechanism study of photocatalyzed synthesis of medium sized ring compounds / Han Li ; Gutachter: Fritz E. Kühn, Hao Guo ; Betreuer: Fritz E. Kühn". München : Universitätsbibliothek der TU München, 2021. http://d-nb.info/1239812493/34.
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