Dissertations / Theses on the topic 'LNMB'

L'utilisation de sources naturelles illimitées telles que l'énergie solaire, éolienne ou hydraulique est en plein essor. Cependant leurs productions énergétiques sont fortement liées aux conditions climatiques et sont donc intermittentes. Ces systèmes nécessitent donc d'être associés à du stockage d'énergie, afin de lisser la production avant injection sur le réseau. Pour toutes ces raisons, les batteries Li-ion doivent intégrer de nouveaux matériaux d'électrode permettant d'obtenir une grande puissance et une haute densité d'énergie, tout en conservant une durée de vie élevée et une sécurité d'utilisation.Dans ce contexte, notre travail a consisté à préparer des matériaux à hauts potentiels, le LiCoPO4 (LCP) et le LiNi0.5Mn1.5O4 (LNMO). Ces derniers s'inscrivent parfaitement dans le contexte de développement de matériaux à haute densité d'énergie puisqu'ils possèdent des potentiels d'oxydation de 4,8 et 4,7 V vs Li +/Li et des densités d'énergies massiques théoriques de 802 et 691 Wh.kg-1 par rapport au lithium, respectivement.Ces matériaux ont d'abord été synthétisés sous forme de couches minces afin d'obtenir des électrodes modèles pour étudier de manière fondamentale les propriétés de transport des matériaux et ses interactions en présence d'un électrolyte liquide notamment les phénomènes à l'interface électrode/électrolyte. La compréhension des matériaux acquise au cours de ce premier axe a permis de transposer et d'adapter ces techniques de caractérisation aux systèmes plus complexes que sont les électrodes composites.Les propriétés de ces matériaux vis-à-vis de l'insertion et la désinsertion du lithium ont ensuite été testées et caractérisées en cellules électrochimiques. De nombreux paramètres cinétiques et thermodynamiques ont été extrait grâce à plusieurs techniques électrochimiques telles que la titration intermittente (GITT), la spectroscopie d'impédance (PEIS et GEIS), le cyclage galvano-statique et les tests de puissance. Nous proposons d'ailleurs une méthode simple, à partir de ces tests de puissance, pour déterminer le coefficient de diffusion du lithium. Enfin, nous tentons de répondre à plusieurs questions qui demeurent en suspens concernant la cyclabilité et la perte de capacité de ces matériaux à haut potentiel au cours de cyclage long et nous proposons une technique très simple permettant d'améliorer de façon étonnamment efficace la cyclabilité d'électrodes composites de LNMO
The use of unlimited natural sources such as solar, wind or hydraulic power is booming. However, their energy production is dependant of climatic conditions and is therefore intermittent. These systems are usually associated with energy storage, in order to smooth the production before injection on the network. For all these reasons, Li-ion batteries need to incorporate new electrode materials to achieve high power and high energy density while maintaining a long life and safe use.In this context, our work consisted in preparing high potential materials, LiCoPO4 (LCP) and LiNi0.5Mn1.5O4 (LNMO). The latter are perfectly integered in the context of development of materials with high energy density since they have an oxidation potential of 4.8 and 4.7 V vs Li + / Li and theoretical mass energy densities of 802 and 691 Wh.kg-1 over lithium, respectively.These materials were first synthesized in the form of thin thin films to obtain model electrodes to study the kinetics and thermodynamics properties of materials transport and interactions with the presence of a liquid electrolyte including phenomena at the electrode interface / electrolyte. The understanding acquired during this first axis allowed us to transpose and adapt these characterization techniques to more complex systems : composite electrodes.The properties of these materials with respect to lithium insertion and desinsertion have been tested and characterized in electrochemicals cells. Kinetic and thermodynamic parameters have been extracted using several electrochemical techniques such as intermittent titration (GITT), impedance spectroscopy (PEIS and GEIS), galvano-static cycling and power tests. We propose a simple method, based on power tests, to determine the diffusion coefficient of lithium. Finally, we attempt to answer several questions that remain unsolved about the capacity loss of high potential materials during long cycling, and we propose a very simple technique for improving the cycling of composites electrodes of LNMO

Дипломний проект на тему "Система живлення високочастотних BUCі LNB на основі застосування універсального інжектора" складається зі вступу, основної частини із чотирьох розділів, висновків, переліку літератури, додатків. Загальний обсяг роботи становить 84 сторінок. Перелік списку літератури складається з 44 найменувань. Мета роботи – аналіз особливостей розробки та практичної реалізації системи живлення високочастотних BUC/LNB. Об’єкт дослідження – проектування системи живлення високочастотних BUC/LNB за допомогою універсального інжектора. Предмет дослідження – особливості застосування засобів математичного моделювання для реалізації клієнт-орієнтованих систем на базі методів САПР. Наукова новизна одержаних результатів. Результати дослідження пропонують альтернативний метод застосування універсального інжектору постійного струму в процесі розробки системи живлення високочастотних BUC/LNB. Практичне значення одержаних результатів полягає в тому, що дослідження ґрунтується на результатах поглибленого вивчення особливостей застосування універсального інжектору постійного струму в процесі розробки системи живлення високочастотних BUC/LNB для засобів супутникового зв’язку.

Un nanotube de dioxyde de titane autoporteur (TiO2 nts) est exploré en tant qu’électrode négative potentielle pour les microbatteries Li-ion 3D. Différentes modifications chimiques du TiO2 ont été explorées et étudiées, comme le TiO2 allié au Nb, le TiO2 revêtu d'ALD-Al2O3, le titanate de lithium-TiO2 et le TiO2 sulfuré. Le dépôt d'électrolyte polymère à base de PEO (oxyde d'éthylène) (PMMA-PEG) portant le sel de LiTFSI dans du TiO2 a été obtenu par la réaction d'électropolymérisation sur l'anode TiO2 et la cathode Lithum nickel oxyde de manganèse (LNMO). L'objectif principal ici était d'exploiter la surface active des électrodes par électrodéposition et d'améliorer ainsi l'interface électrode-électrolyte. Une telle micro-batterie contenant des électrodes revêtues de polymère révèle que les valeurs de capacité obtenues à différents taux de C sont doublées lorsque les électrodes sont complètement remplies par l'électrolyte polymère par rapport à la micro-batterie à électrodes brutes. Les excellentes performances électrochimiques sont attribuées aux interfaces électrode-électrolyte améliorées dans les deux électrodes
Self-supported titanium dioxide nanotube (TiO2 nts) is explored as a potential negative electrode for 3D Li-ion microbatteries. Different chemical modifications on the TiO2 nts have been explored and studied like Nb-alloyed TiO2 nts, ALD-Al2O3 coated TiO2 nts, Lithium titanate-TiO2 nts and sulphurized TiO2 nts. The deposition of PEO (polyethylene oxide) based polymer electrolyte (PMMA-PEG) carrying LiTFSI salt into TiO2 nts has been achieved by the electropolymerization reaction on the TiO2 nts anode and the Lithum nickel manganese oxide (LNMO) cathode. The main aim here was to exploit the active surface area of the electrodes using electrodeposition and there by enhance the electrode-electrolyte interface. Such a microbattery containing polymer-coated electrodes reveal that the capacity values obtained at different C-rates are doubled when the electrodes are completely filled by the polymer electrolyte compared with the microbattery with the raw electrodes. The excellent electrochemical performance is attributed to the improved electrode-electrolyte interfaces in both the electrodes

En el presente trabajo de tesis se realiz�� la s��ntesis de nanopart��culas de TiO2 dopadas y no dopadas con Europio (Eu+3), se utiliz�� el m��todo de sol-gel variando las condiciones de reacci��n con el fin de establecer los par��metros m��s apropiados para controlar su tama��o y dispersi��n. Se estudi�� la relaci��n entre sus condiciones de s��ntesis y dopaje con sus propiedades optoelectr��nicas. Es importante mencionar que el control sobre la morfolog��a, tama��o, y fase cristalina es de vital importancia para determinar las posibles propiedades del producto que posteriormente influyen sus aplicaciones tecnol��gicas. La hidr��lisis controlada de but��xido de titanio favorece la s��ntesis de las nanopart��culas de TiO2 dopadas y no dopadas con europio (Eu) a diferentes porcentajes molares, se observ�� que el porcentaje molar de dopaje influye en el tama��o final de las NPs. Es importante mencionar que el m��todo utilizado para el dopaje involucra m��nimas cantidades de reactivos con el fin de evitar la formaci��n de productos no deseados y contaminaci��n del material de inter��s.
(cont.) Las NPs obtenidas resultaron en una estructura amorfa y fueron tratadas t��rmicamente a determinadas temperaturas en aire para inducir la fase cristalina anatasa. Las nanoparticulas de TiO2 dopadas con Eu fueron sometidas a estudio de fotoluminiscencia (PL) con el objetivo de determinar los efectos del dopante sobre las propiedades optoelectr��nicas y evaluar sus posibles aplicaciones tecnol��gicas, su caracterizaci��n fue realizada mediante microscop��a SEM para la evaluaci��n del tama��o y morfolog��a de las NPs dopadas y no dopadas, se llev�� a cabo la caracterizaci��n por EDS para estudiar su composici��n de manera cualitativa y cuantitativa, la caracterizaci��n estructural por difracci��n de rayos X y espectroscopia Raman, y la evaluaci��n de sus propiedades optoelectr��nicas se realiz�� por medio de espectroscopia de fotoluminiscencia PL. Los resultados de todas las pruebas se discuten en el presente trabajo. Finalmente, este trabajo de investigaci��n consiste en la preparaci��n y caracterizaci��n de las nanoparticulas de TiO2 dopadas y no dopadas llevando a cabo procedimientos sencillos y econ��micos para promover sus usos m��s populares

Se sintetizaron exitosamente nanopartículas magnéticas por el método de descomposición térmica, utilizando dos diferentes polioles. Los polioles empleados son el agente de recubrimiento, ayudando a estabilizarlas y a determinar la morfología de las nanopartículas. La estructura y la morfología de las nanopartículas fueron analizadas utilizando FTIR, SEM, TEM, DRX y DLS. Su función como agentes de contraste en imagenología de resonancia magnética nuclear, fue evaluada utilizando un equipo médico de resonancia de 1.5 T. Los resultados muestran que las nanopartículas sintetizadas son monodispersas, superparamagnéticas, biocompatibles en los modelos estudiados en este trabajo de investigación y tienen una posible aplicación como agentes de contraste en imagenología de resonancia magnética nuclear. ABSTRACT Magnetic nanoparticles were synthesized by thermal decomposition method, using two different polyols. Polyols are used as coating agents, helping determining nanoparticles stability and morphology. The structure and morphology of the nanoparticles were studied using FTIR, SEM, TEM, DRX and DLS. Their function as MRI contrast agents was studied using a 1.5 T MRI equipment. The results show that the produced nanoparticles are monodisperse, superparamagnetic, biocompatible for the studied models and a potential use as contrast agents in MRI techniques.

El desarrollo de la electrónica flexible ha sido posible gracias al uso de substratos flexibles. Los circuitos electrónicos construidos sobre estos substratos tienen un gran potencial para un gran número de aplicaciones incluyendo pantallas, celdas solares, dispositivos móviles, textiles, inclusive implantes compatibles con biosistemas. Sin embargo, los substratos flexibles no son completamente compatibles con los procesos existentes de microfabricación debido a las altas temperaturas que se utilizan. Para solucionar el problema es necesario el uso de semiconductores policristalinos o amorfos, depositados a bajas temperaturas, el desarrollo de nuevas técnicas de microfabricación, nuevos materiales, con el fin de lograr un buen funcionamiento del dispositivo. Los transistores de película delgada comúnmente se fabrican con silicio amorfo hidrogenado (a-Si:H) a temperaturas menores o iguales a 300ºC. Sin embargo la movilidad de los portadores de corriente de este material es de aproximadamente 1 cm2/Vs. Materiales amorfos, como el silicio-germanio amorfo hidrogenado (a-SiGe:H), son una alternativa para resolver el problema de la movilidad y de la temperatura. Trabajos realizados en el INAOE han demostrado que la movilidad de los portadores de carga se incrementa sin aumentar la temperatura de depósito. Se busca fabricar TFT´s de a-SiGe:H sobre teflón (Polytetraflouroethylene) y PEN (Polyethylene naphthalate) a bajas temperaturas y obtener sus propiedades eléctricas.

Toxicity of cerium oxide nanoparticles was tested in different biological models such as prokaryotic (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis spores), eukaryotic yeast, germination radicle and development of Lactuca sativa seed as well as damage to human leukocyte DNA. The nanoparticles were sonicated at different pH values and time, and then mixed with three different surfactants (i.e. PVP Polyvinylpyrrolidone, Triton X114 and Tween 80) at 0.002% v/v. It was found that sonication enhanced colloidal dispersion and produced an average particle size of 400 nm. The material was toxic to E. coli at pH 7 when sonicated and M9 minimal media was used. The toxic effect on minimal media increased when non-ionic surfactants were added. The use of CeO2 plus surfactant improved the minimal inhibitory concentration (MIC) against E. coli using Tween 80. The most striking effect occurred with this surfactant resulting in a MIC value of 0.150 mg mL-1 compared to 3 mg mL-1 of cerium oxide alone. Regarding the germination model, it was found that the toxic concentration was 0.5 mg mL-1. At this concentration germination was observed, but not radicle growth. It was found that leukocyte DNA was affected in a concentration of 1 mg mL-1for the tested nanoparticles in all tested conditions. These findings suggest the importance of the different factors interacting with the nanoparticles, such as surfactants, particle size, synthesis method, the physical chemistry of nanomaterials and the type of test organisms can affect in different ways the distinct prokaryotic and eukaryotic and lead to an unexpected toxic effect in materials considered as innocuous. In consequence, in the future this could affect the environment and microscopic and macroscopic organisms.

Les lymphomes ont causé 557 730 décès dans le monde en 2018 et sont la 5ème cause de mortalité due à un cancer en France. Les recherches fondamentales et appliquées dans ce domaine sont donc cruciales pour améliorer les diagnostics et les thérapies. Les voies de signalisation cellulaire du facteur de transcription NF-κB, jouant un rôle central dans la survie et la prolifération de la cellule, sont fréquemment dérégulées et impliquées dans l’émergence des lymphomes non Hodgkinien des cellules B (LNHB). Les études menées au laboratoire sur ces trois années concernaient le rôle de MYD88 et de NF-κB dans le contexte de l’émergence des lymphomes liés à la cellule B. La mutation L265P de la protéine adaptatrice MYD88 (MYD88L265P), exacerbant la signalisation des « toll like receptor » (TLR), récepteurs impliqués dans la réponse immunitaire innée de la cellule B entraîne une activation constitutive de NF-κB. La protéine mutée MYD88L265P est retrouvée dans de nombreux cas de LNHB allant des lymphomes lymphoplasmocytaires (LLP) indolents aux lymphomes agressifs diffus à grandes cellules B (DLBCL). La macroglobulinémie de Waldenström (MW) présente dans environ 90% des cas, cette mutation MYD88L265P, faisant d’elle un évènement primaire dans l’émergence de ce LLP. Pour pouvoir étudier les conséquences d’une telle mutation sur la transformation de la cellule B, nous avons réalisé une étude in vivo, via un modèle murin exprimant MYD88L252P (orthologue murin de la mutation MYD88L265P chez l’humain) seulement des cellules B grâce à l’expression de la CRE-recombinase via le promoteur du gène Cd19. En effet, l’étude de ce modèle développant un lymphome présentant des similarités avec la MW, nous a permis de visualiser son pouvoir transformant sur la cellule B, mais aussi le comportement de la cellule dans le microenvironnement d’un organisme entier. Nous avons pu confirmer l’aptitude de MYD88L252P à former un clone lymphoplasmocytaire, ainsi que la présence d’un pic d’IgM monoclonal dans le sérum et une invasion de plasmocytes à IgM dans la moelle osseuse, qui sont des caractéristiques de la MW.L’échappement immunitaire est une composante majeure dans l’émergence des LNHB. Dans le cas des lymphomes liés au virus d’Epstein Barr (EBV), les cellules B immortalisées par ce virus sont aussi aptes à moduler la réponse immunitaire qui leur est adressée. Concernant ce dernier phénomène, nous avons décrit le profil immunorégulateur in vitro de cellules B infectées par l’EBV en latence III. La protéine LMP1, produite lors de la latence II et III, active essentiellement la voie canonique de NF-κB, et permet la surexpression des protéines immunomodulatrice PD-L1, IL-10, TGF- β1 et IL35 (EBI3 et IL12A). Nous avons aussi mis en évidence, l’expansion des cellules T régulatrices (Treg) conventionnelles et non conventionnelles dépendant de l’axe PD-1/PD-L1. Dans de nombreux cancers, la protéine de surface PD-L1 est surexprimée impactant fortement le microenvironnement des cellules tumorales. Ainsi, dans le cas des DLBCL, cette surexpression est associée à un mauvais pronostic. Du fait de son importance dans la progression de la tumeur, les tests thérapeutiques avec des anticorps anti-PD-L1 peuvent se révéler être très efficaces. Pour cela, nous avons réalisé des tests précliniques in vivo ciblant PD-L1 directement, et ex vivo ciblant les voies permettant son expression dans le modèle murin L.CD40 (lmp1/cd40) développant un lymphome indolent se rapprochant du lymphome de la zone marginale (LZM) dans lequel nous avons montré que les tumeurs B surexprimaient la protéine PD-L1. Nous avons pu démontrer les effets bénéfiques de ce traitement avec une réduction de la taille de la rate in vivo, une diminution de l’expression du gène PD-L1 ex vivo et une réactivation des cellules T. Ce travail ouvre de nouvelles perspectives de recherche sur l’échappement à la réponse immune dans les LNHB associés à la mutation activatrice de MYD88
It was estimated that 557 730 deaths from lymphoma worldwide in 2018 and are the 5th leading cause of cancer death in France. Basic and applied research in this area is therefore crucial to improve diagnostics and therapies. Cell signaling pathways of the transcription factor NF-κB, playing a central role in cell survival and proliferation, are frequently deregulated and involved in the emergence of non-Hodgkin B-cell lymphomas (B-NHL). The laboratory studies over these three years concerned the role of MYD88 and NF-κB in the context of the emergence of B cell-linked lymphomas. The L265P mutation of protein adaptor MYD88 (MYD88L265P), exacerbating toll-like receptor (TLR) signaling, receptors involved in the innate immune B cell response, results in constitutive NF-κB activation. This mutated protein MYD88L265P is found in many cases of LNH ranging from indolent lymphoplasmacytic lymphomas (LPL) to aggressive diffuse large B-cell lymphomas (DLBCL). Waldenström's macroglobulinemia (WM) presents in about 90% of cases this MYD88L265P mutation, making it a primary event in the emergence of this LPL. To study the consequences of this mutation on the transformation of the B cell, we carried out a in vivo study, thanks to a murine model expressing MYD88L252P (murine ortholog of the MYD88L265P mutation in humans) exclusively in B cells through the expression of CRE-recombinase due to the Cd19 promotor. Indeed, the study of this model developing a lymphoma close to WM, allowed us to visualize its transforming power on the B cell, but also the behavior of the cell in the microenvironment of an entire organism. We were able to confirm the ability of MYD88L252P to form a lymphoplasmacytic clone, as well as the presence of a serum monoclonal IgM peak and an IgM plasma cells invasion in the bone marrow, which are characteristics of WM.Immune escape is a major component in the emergence of B-LNH. In the case of lymphomas linked to the Epstein Barr virus (EBV), the B cells immortalized by this virus are also able to modulate the immune response. Regarding this last phenomenon, we have described the immunoregulatory profile in vitro of B cells infected by EBV in latency III. The LMP1 protein, produced during latency II and III, essentially activating the NF-κB alternative pathway, allows the overexpression of the immunomodulatory proteins PD-L1, IL-10, TGF-β1 and IL35 (EBI3 and IL12A). We have also demonstrated the expansion of conventional and unconventional regulatory T cells (Tregs) depending on the PD-1/PD-L1 axis. In many cancers, the PD-L1 surface protein is overexpressed, strongly impacting the microenvironment of tumor cells. Thus, in the case of DLBCL, this overexpression associated to poor prognosis. Due to its importance in the progression of the tumor, therapeutic tests with anti-PD-L1 antibodies can be very effective. For this, we did preclinical in vivo tests targeting PD-L1 directly, and ex vivo targeting the pathways allowing its expression. The L.CD40 (lmp1/cd40) murine model developing indolent lymphoma close to marginal zone lymphoma (MZL), in which we shown the overexpression of PD-L1 from tumoral B cells. We were able to demonstrate the beneficial effects of this treatment with a in vivo spleen size reduction and ex vivo PD-L1 downregulation, as well as T cell reactivation. These studies open new research perspectives on our MYD88 mouse model

L'experience ATLAS, installee au CERN, exploitera les collisions de protons du LHC pour approfondir le Modele Standard, et chercher d'éventuelles traces de nouvelle physique. L'une de ses tâches principales sera la recherche du boson de Higgs. Cette these décrit d'abord les derniers algorithmes d'etiquetage des jets b en date, et propose une methode de calibration basee sur les premieres donnees que le d´etecteur recueillera à partir de 2007. Puis l'hypothese d'un boson de Higgs de faible masse (mH < 135 GeV/c2) est consideree. Dans cette plage de masse, il devrait se désintegrer preferentiellement en une paire de quarks b. Le canal ttH a ete etudie pour la premiere fois en simulation détaillée, et avec les methodes d'etiquetage des jets b les plus récentes. Pour une luminosité integree de 30 fb−1 (trois ans de prise de données), le rapport S/pB caractérisant la sensibilité de cette analyse est 4,9, permettant une observation non ambigüe du boson de Higgs dans ce canal.

碩士
大同大學
化學工程學系(所)
101
Storage ageing effects of commercial lithium-ion battery with composite LMO-LNMC cathode material has been investigated in this study. Sixteen sets of batteries were stored in four temperatures each with four depths of charge for six months. The batteries were charged and discharged at a constant current every month, and the impedances were determined in order to investigate the change inside the battery during charge and discharge, and to investigate the phenomenon of battery ageing. Results show that capacity decrease of the commercial batteries stored between 0℃ and 60℃and between 25% DOC and 100% DOC can be expressed as: where Q is dimensionless capacity [ - ], t is ageing time [day], DOC is depth of charge [ - ], T is temperature [K] and k1 is rate constant of capacity decrease [1/day]. The impedance increase can be expressed by where RE is the dimensionless impedance [ - ], k2 is the rate constant of impedance increase [1/day]. The experimental data of Q and RE are consistent with model calculations. Increasing storage temperature or depth of charge increases the ageing of battery, including capacity decrease and impedance increase. Battery ageing results in the shift of peak (valley) of the plot of dQ/dV vs V towards high voltage side, as well as in the decrease of the height (depth) of the peak (valley). The storage ageing effect is not obvious if the battery is stored below 25℃, regardless of the depth of charge. On the contrary, at temperature of 60℃ and depth of charge of 100%, the ageing effect is most obvious. At this condition, the capacity decreases by 16% and impedance increases by 70% after 6 months.

The study was planned to investigate issues relating to the Luria-Nebraska Neuropsychological Battery. The aims were to investigate the influence of age, sex and socio-economic status on performance on the Luria-Nebraska Neuropsychological Battery. A sample of forty males and forty females, stratified according to age (25-40 year olds and 50-60 year olds) and socio-economic status was selected. The results suggested that age formed a significant effect on the total and individual scale scores of the battery. There were no significant sex differences on the total score and most of the scale scores of the battery. Sex formed a significant variable on the performance on the intellectual processes and visual scales. A significant negative correlation was found between total and scale scores of the Luria-Nebraska Neuropsychological Battery and socio-economic status. The implications of these findings are discussed.
Thesis (M.A.)-University of Durban-Westville, Durban, 1991.

Thermoelectric phenomena like the Seebeck and Peltier effects are known for more than two centuries with a wide range of applications. In 2008 Uchida et al. first demonstrated the phenomena called Spin Seebeck Effect (SSE) in which spin currents are generated in a ferromagnetic (FM) material in the presence of a magnetic field with an applied temperature gradient. These spin currents were electrically detected in an adjoining heavy metal layer (usually Pt) employing the Inverse Spin Hall effect (ISHE). The absence of charge currents in insulators meant reduced losses due to joule heating and hence the interest in ferromagnetic insulator (FMI) based spintronic devices wherein spin information gets transferred by pure magnon spin waves. In 2012 another unusual magnetoresistance effect called the Spin Hall Magnetoresistance (SMR), was discovered in similar Pt/FMI bilayers in which the resistance of the Pt layer could be modulated by the magnetization orientation of the FMI layer underneath. Subsequently, both SSE and SMR have been explored in a wide range of magnetic materials with exotic magnetic structures both for its rich physics and potential application as thermoelectric materials. In this regard, we have investigated these phenomena in different spintronic materials across their magnetic phase transition. We start with a description of the various experimental arrangements developed in-house to perform steady-state measurement of longitudinal SSE and SMR in a broad range of magnetic fields and temperatures. Next, we outline the fundamental characteristics of both phenomena revealed by our investigations on YIG single crystals in bulk and thin film form. Following the optimization of measurement conditions on YIG, we probe the competing interactions at low temperature in MgFe2O4 (MFO), which forms part of another popular class of insulating magnetic material, ferrites. Enhanced SSE was observed in Pt/MFO bilayers, hosting both Ferromagnetic and Antiferromagnetic (AFM) interactions. A simple model that considers a distribution of anisotropy energies for the AFM could corroborate our experimental findings. In the second part, we will discuss the temperature evolution of the SSE across ferromagnet to paramagnet phase transition in Pt/EuO1−x and Pt/La2NiMnO6 heterostructures, where we try to resolve a longstanding disparity between theoretical predictions and experimental evidence with regards to the nature of power law decay of the SSE while approaching the ferromagnetic phase transition temperature (TC). We conclusively demonstrate a correlation between the critical exponents of SSE and magnetization for both FMs. We substantiate our results by extracting spin mixing conductance, (Gmix) from SMR study on LNMO, which emphasize the role of Gmix in determining thermal spin pumping. At the end, we will highlight the effect of anisotropy on SMR and the related phenomena, anisotropic magnetoresistance (AMR). The nature of SMR in epitaxial LNMO films on STO (001) suggested that the magnetic structure of the LNMO surface was different from the bulk of the film. Considering a uniaxial magnetic anisotropy of the surface oriented along (110), we could reproduce most of the observed features. On the other hand, these MR phenomena in polycrystalline EuO1-x on Si (100) serve as a sensitive probe for its bandstructure.

碩士
長庚大學
基礎醫學研究所
95
The classical G protein-coupled receptors (GPCRs) control many physiological responses through one polypeptide chain, which normally consists of a 7TM domain and a short extracellular domain. In contrast, the novel class B2 GPCRs (LNB-TM7) have been found to undergo post-translational autoproteolysis at the G protein-coupled receptor proteolytic site (GPS) located within a conserved Cys-rich domain that is upstream of the first transmembrane segment. Therefore, the GPS autoproteolysis of LNB-TM7 receptors produces constitutively two subunits, a large extracellular domain (α-subunit) resembling cell- adhesion protein and a TM7 domain (β-subunit) that is a typical TM7 moiety of GPCR, from a single polypeptide chain in the endoplasmic reticulum soon after the receptor biosynthesis. The proteolytic mechanism is mediated by a self-catalyzed reaction commonly employed by the N-terminal nucleophile hydrolase style autoproteolysis. Intriguingly, the cleaved α-subunit was shown to remain firmly on the cell membrane. It has long been believed that the tight plasma membrane association is due to the non-covalent interaction with β-subunit. Hence, the LNB-TM7 heterdimer receptors are thought to function through ligand binding or protein-protein interaction via the α-subunit, followed by signal transduction via the β-subunit. In a recent study, Volynski et al. demonstrated that the α-subunit and β-subunit of latrophilin, a LNB-TM7 receptor for -latrotoxin, do not normally interact on the cell membrane, but behave rather as separate entities responsible for ligand binding and cellular signaling, respectively. However, the functional roles of GPS autoproteolysis and the fate of the α-subunit and β-subunit on the cell membrane remain to be identified. Using EMR2, a well characterized membrane of the EGF-TM7 family as a model molecule, we investigated the fates of the cleaved α-subunit and β-subunit. We now demonstrate that the α-subunit is likely anchored on the membrane directly by itself and the β-subunit is partially localized in the lipid raft. Nevertheless, separated α-subunit and β-subunit can re-associate in soluble form. Hence, we propose a model where the agonist binding to the α-subunit induces re-association to the β-subunit in the lipid raft and promotes signal transduction via the β-subunit.

博士
國立臺灣大學
生化科學研究所
102
Bifidobacteria, gram-positive anaerobic bacteria, feature a unique lacto-N-biose I (LNB)/galacto-N-biose (GNB) pathway to utilize LNB and GNB for colonization in the gastrointestinal tract of humans. The LNB/GNB pathway is encoded in a four-gene lnpABCD operon. Galacto-N-biose/lacto-N-biose I phosphorylase (GLNBP) encoded by the gene lnpA catalyzes phosphorolysis of LNB and GNB into galactose-1-phosphate (Gal-1P) and N-acetyl-D-hexoamine (GlcNAc/GalNAc) without ATP consumption. This maximizes the effectiveness of ATP production under anaerobic conditions. A novel N-acetylhexosamine 1-kinase (NahK) encoded by the gene lnpB then phosphorylates N-acetyl-D-hexoamine to N-acetylhexoamine 1-phosphate (GlcNAc-1P/GalNAc-1P). NahK has been extensively used in chemoenzymatic synthesis of carbohydrates. However, the molecular mechanisms for both GLNBP and NahK remain unclear. In this study, we wanted to determine the crystal structures of GLNBP and NahK in complex with substrates/products to gain insight into the catalytic mechanisms of these two enzymes. For GLNBP, crystal structures of GLNBP in complex with LNB/GNB were solved. Based on the structural information, GLNBP was proposed to proceed through an inverting phosphorolytic reaction by the direct nucleophilic attack of an inorganic phosphate at the anomeric carbon. For NahK, seven 3-D structures of NahK in complex with GlcNAc, GalNAc, GlcNAc-1P, GlcNAc/AMPPNP and GlcNAc-1P/ADP were solved. Based on these snapshot structures, a direct in-line phosphoryl transfer mechanism was proposed. The NahK structures presented here represent the first multiple-reaction complexes of the enzyme. The demonstration of the protein crystal structures and the elucidation of the catalytic mechanisms would provide useful information for expanding the utilizations of both GLNBP and NahK to a great extent.

Trabalho de Projeto do Mestrado em Português como Língua Estrangeira e Língua Segunda (PLELS) apresentado à Faculdade de Letras
A definição de um conjunto de perguntas (FAQ) para exploração de valências de pesquisa em corpora informatizados de produções escritas e orais de aprendentes de português língua não materna, a partir de uma plataforma digital, tem como principal objetivo orientar o utilizador na extração de dados consistentes destes acervos.Na génese deste projeto estão dois corpora que disponibilizam dados de aprendentes de português língua não materna com vista à sustentação empírica da investigação no âmbito da aquisição/aprendizagem de língua não materna, à fundamentação de práticas pedagógicas e, ainda, à criação de novos instrumentos didáticos: o corpus de Produções Escritas de Aprendentes de PL2 (PEAPL2_PLE) e o Corpus Oral de Português L2 (COral-Co).Estes corpora foram disponibilizados online a partir do TEITOK, uma plataforma que possibilita a pesquisa através do Corpus Query Processor (CQP), uma ferramenta flexível e eficiente, mas cuja rentabilização está condicionada, essencialmente, pelos processos de inserção e edição dos dados na plataforma e pela complexidade das expressões de pesquisa.Assim, as virtualidades da pesquisa em corpora informatizados de aprendentes, por um lado, e os constrangimentos à pesquisa que se podem colocar, por outro, motivaram a definição de um conjunto de FAQ com o objetivo de orientar o utilizador na exploração de corpora e rentabilizar as potencialidades da plataforma de pesquisa. As perguntas e as respetivas respostas encontram-se disponíveis para consulta online, na página de pesquisa de cada um dos referidos corpora, em dois formatos (PDF e mp4).Este modelo de construção de FAQ, baseado nos objetivos inerentes à construção de corpora e nas valências de pesquisa do CQP, potencia a atualização e o aperfeiçoamento deste tipo de help search e a sua replicação em corpora desenvolvidos a partir do TEITOK.
The definition of a set of questions (FAQ) for the exploration of research valences in computerised corpora of oral and written production of Portuguese as a Second or Foreign Language learners, on a digital platform, has as main goal to guide the user in the extraction of data from such collection.In the genesis of this project are two corpora that provide data of Portuguese as a Second or Foreign Language learners for the empirical support of the research in the scope of the acquisition/learning of a second or foreign language, the rationale of education practices, and the creation of didactic instruments: the Corpus de Produções Escritas de Aprendentes de PL2 (PEAPL2_PLE) and the Corpus Oral de Português L2 - Coimbra (COral-Co). These corpora have been made available online on TEITOK, a platform that allowed the research through the Corpus Query Processor (CQP), a flexible and efficient tool, but whose effectiveness is conditioned, mainly, by the data insertion and editing processes in the platform, and by the complexity of the research expressions.As such, the virtualities of the research in computerised corpora of learners, o non e hand, and the restraints that may occur on the research, on the other, have led to the definition of a set of FAQ with the purpose of guiding the user in the exploration of corpora and retrieving higher benefit from the research platform capabilities. The questions as the corresponding answers are available for online check in the research page of each of the mentioned corpora, in two formats (PDF and mp4).This model of FAQ construction, based on the goals inherent to the construction of corpora and the CQP’s research valences, empower the update and perfecting of this type of help search and its replication in corpora developed in TEITOK.