Дисертації з теми "Cellular Ceramics"
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Guzi, De Moraes Elisangela. "Advanced cellular ceramics processed using direct foaming methods." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424015.
Повний текст джерелаMateriali ceramici a base di Si3N4 altamente porosi sono potenziali candidati per varie applicazioni di ingegneria: filtraggio di gas ad alta temperature ed in condizioni critiche, isoltaori termici, trasporto di catalizzatori, bioreattori e impianti biomedici (recenti risultati di letteratura hanno confermato la non citotossicità e la biocompatibilità del Si3N4). L’attività di ricerca della presente tesi riguarda lo sviluppo di materiali ceramici a base di nitruro di silicio caratterizzati da una struttura cellulare, contenenti porosità interconnessa (> 80 vol%) e celle con una distribuzione dimensionale che varia dai 10 μm fino agli 800 μm. La tecnica utilizzata per la produzione dei materiali ceramici cellulari consiste nella schiumatura diretta; sono state sviluppate emulsioni concentrate (O/W olio-in-acqua) stabilizzate da tensioattivi e gelcasting di biopolimeri ecocompatibili, come step intermedi nella produzione di materiali inorganici altamente porosi. Diversamente dai tradizionali metodi di schiumatura diretta, la schiumatura è fornita dall’ evaporazione (ed espansione) delle gocce di alcani durante l'essiccazione delle emulsioni. Mentre nel caso di gelcasting, la capacità dei tensioattivi schiumogeni combinata con la gelificazione termica fornisce la schiumattura. Nel caso della produzione di componenti a base di nitruro di silicio la sinterizzazione rappresenta un punto critico, poiché sono necessarie temperature elevate e prolungato tempo di mantenimento alla T di sinterizzazione al fine di garantire sufficiente densificazione a causa delle basse velocità di diffusione allo stato solido. Al fine di superare queste difficoltà, nella presente tesi sono state sviluppate due strategie: 1) Sinterizzazione convenzionale a 1600 °C e 1700 °C in flusso di N2, al fine di inibire le reazioni di dissociazione e sinterizzare con basse perdite di peso. 2) Sinterizzazione con intensa radiazione termica, attraverso la tecnica dello Spark Plasma Sintering (SPS), la quale si è dimostrata efficace al fine di densificare gli struts della schiuma e sviluppare nanofili di SiC sulle pareti di cella e sugli struts, a temperature più basse e per tempi più brevi rispetto alla sinterizzazione convenzionale. Nanofili di SiC contribuiscono ad aumentare la resistenza alla frattura delle schiume. Inoltre, l’influenza di addittivi di sinterizzazione, Y2O3 e MgO, sulla temperatura di sinterizzazione e sulla formazione di β–Si3N4 grains, sono stati investigati. Le strutture cellulari a base di Si3N4 prodotte con le tecniche sopra descritte sono state caratterizzate in termini di microstruttura (distribuzione della dimensione di celle e porosità), proprietà meccaniche (test di compressione) e permeabilità ai gas. Porosità totale che varia dai ~74 fino agli 89 vol%, e le dimensioni delle celle variano in un ampio range ~20 fino agli 850 μm, in funzione della velocità di emulsione, tipici di biopolimeri. E’ stato trovato che le schiume sinterizzate a 1700 °C (sinterizzazione convenzionale) sono caratterizzate da elevati valori di resistenza a compressione up to 33MPa per effetto dello sviluppo di grani allungati di fase β–Si3N4 e per effetto della notevole densificazione delle particelle in corrispondenza delle pareti di cella e degli struts. Le misure di permeabilità hanno dato valori di costanti di permeabilità nel range delle schiume ottenute con la tecnica del gelcasting e sono pertanto utili per applicazioni di filtraggio. La combinazione di processi colloidali, schiumatura, rapida consolidazione delle schiume e sinterizzazione in assenza di pressione a temperature moderate applicate ai ceramici porosi a base di Si3N4, sono state applicate anche ad altri sistemi come ad esempio al sistema Ti-Al-C (Max-Phases).
Barg, Suelen [Verfasser]. "Cellular Ceramics via Alkane Phase Emulsified Powder Suspensions / Suelen Barg." Aachen : Shaker, 2010. http://d-nb.info/1081886919/34.
Повний текст джерелаInostroza, Pilar Angelica Sepulveda. "Processing of cellular ceramics synthesised by gel casting of foams." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301868.
Повний текст джерелаKulkarni, Apoorv Sandeep. "Ceramic Si-C-N-O cellular structures by integrating Fused Filament Fabrication 3-D printing with Polymer Derived Ceramics." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/349905.
Повний текст джерелаFranchin, Giorgia. "Additive Manufacturing of Ceramics. Printing Beyond the Binder." Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3426205.
Повний текст джерелаQuesto progetto di ricerca riguarda la produzione di ceramici tramite tecniche di manifattura additiva (AM), con particolare focus su tecnologie estrusive. Il principale vantaggio dell’AM è la possibilità di produrre strutture cellulari ad elevata complessità e porosità controllata, consentendo di produrre reticoli stretch-dominated leggeri ma efficienti. L’ispirazione è offerta dalla natura: le strutture ossee sono un ottimo esempio, in quanto si compongono di un involucro esterno, denso e sottile, e di un cuore a struttura cellulare altamente porosa. I sistemi di AM disponibili in commercio per la produzione di componenti ceramici sono molto pochi, e la maggior parte di essi utilizza polveri ceramiche. È molto difficile evitare porosità residua e cricche, e di conseguenza si ottengono oggetti dalla resistenza limitata e privi delle peculiarità di alcuni materiali, come ad esempio la trasparenza del vetro. Le tecnologie di AM che utilizzano polimeri sono ad uno stadio di sviluppo molto più avanzato. L’obiettivo è di sfruttare tale vantaggio e di fornire alternative agli approcci polvere-legante. Sono stati esplorati tre diversi materiali: polimeri preceramici, geopolimeri, e vetro. Un unico polimero preceramico, un polisilsesquiossano commerciale, è stato utilizzato come legante reattivo, non sacrificale per lo sviluppo di inchiostri per stereolitografia (SL) e direct ink writing (DIW). La prima tecnologia ha consentito di produrre micro-componenti in SiOC densi e privi di cricche, con una dimensione dei pilastri fino a ~200 μm e ottima qualità superficiale. Non ci sono state limitazioni di forma, anche se strutture porose o oggetti densi di piccole dimensioni sono da preferire per evitare porosità residua e cricche. Il secondo approccio ha portato alla fabbricazione di scaffold bioceramici per ingegneria tissutale con filamenti di diametro 350 µm e parti non supportate. Il polimero preceramico ha il doppio ruolo di fonte di silice e di modificatore reologico. Sono stati prodotti anche compositi a matrice ceramica (CMCs); il polimero preceramico sviluppa la matrice (SiOC) tramite pirolisi in atmosfera inerte, mentre il rinforzo è dato da fibre di carbonio macinate. Componenti in geopolimero a porosità controllata sono stati progettati e prodotti prima tramite replica negativa di template sacrificali in PLA, e poi via DIW. Il secondo approccio ha portato alla produzione di reticoli ceramici con filamenti di ~800 μm e parti non supportate con deflessione molto limitata. È stato sviluppato infine un innovativo processo estrusivo a partire da vetro fuso. Un unico sistema è in grado di lavorare il vetro dallo stato fuso fino alla ricottura di componenti complessi progettati digitalmente. Sono stati realizzati oggetti comprendenti sporgenze di diversa entità e piccoli raggi di curvatura. All’interno dello spazio di progettazione è stato possibile stampare con elevata precisione e accuratezza; le parti stampate mostrano una forte adesione tra gli strati e un’elevata trasparenza attraverso di essi.
Schultz, Joshua Andrew. "Mathematical modeling and control of a piezoelectric cellular actuator exhibiting quantization and flexibility." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45776.
Повний текст джерелаKlang, Katharina [Verfasser]. "The energy dissipation of the sea urchin spine as biomimetic concept generator for cellular ceramics and load-bearing systems / Katharina Klang." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1219064521/34.
Повний текст джерелаBorchardt, Lars, Claudia Hoffmann, Martin Oschatz, Lars Mammitzsch, Uwe Petasch, Mathias Herrmann, and Stefan Kaskel. "Preparation and application of cellular and nanoporous carbides." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138910.
Повний текст джерелаDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
Borchardt, Lars, Claudia Hoffmann, Martin Oschatz, Lars Mammitzsch, Uwe Petasch, Mathias Herrmann, and Stefan Kaskel. "Preparation and application of cellular and nanoporous carbides." Royal Society of Chemistry, 2012. https://tud.qucosa.de/id/qucosa%3A27792.
Повний текст джерелаDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
Sridevi, Priya Alexander Hannah Ben-Ze'ev Alexander Stephen. "Regulation of ceramide synthase 1 in cellular stress response." Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/6690.
Повний текст джерелаBelaud-Rotureau, Marc-Antoine. "Etude de l'apoptose induite par le ceramide et les anthracyclines dans les cellules leucemiques (doctorat : biologie moleculaire et cellulaire)." Paris 5, 2000. http://www.theses.fr/2000PA05W066.
Повний текст джерелаSnelling, Jr Dean Andrew. "A Process for Manufacturing Metal-Ceramic Cellular Materials with Designed Mesostructure." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/51606.
Повний текст джерелаPh. D.
Nieh, Cuo-Yo. "Priming and temperature loss of steel in a cellular ceramic filter." Case Western Reserve University School of Graduate Studies / OhioLINK, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1054825028.
Повний текст джерелаSnelling, Dean Andrew Jr. "A Process for Manufacturing Metal-Ceramic Cellular Materials with Designed Mesostructure." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51606.
Повний текст джерелаPh. D.
Deng, Honghua Materials Science & Engineering Faculty of Science UNSW. "Effect of cation addition on cellular response and bone ingrowth into three dimensional porous bioceramics." Awarded by:University of New South Wales. Materials Science & Engineering, 2008. http://handle.unsw.edu.au/1959.4/43733.
Повний текст джерелаSiegkas, Petros. "Static and dynamic performance of Ti foams." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:68938d12-d104-4637-8b08-d1c126ddca84.
Повний текст джерелаKarumuri, Anil Kumar. "Interfacial Modification of Microcellular Carbon: Influence of Ceramic and Carbon Nanotube Coatings." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1262043697.
Повний текст джерелаVAKIFAHMETOGLU, CEKDAR. "FABRICATION AND CHARACTERIZATION OF POROUS CERAMICS WITH HIERARCHICAL POROSITY." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3422377.
Повний текст джерелаIl lavoro di ricerca esposto nella presente tesi riguarda la produzione di componenti porosi mediante l’uso di polimeri preceramici quali precursori iniziali. Durante una fase preliminare del lavoro di ricerca, sulla quale si è basata la produzione di ceramici cellulari derivati da polimeri, sono state studiate varie composizioni. Ceramici cellulari di SiOC aventi una morfologia complessa sono stati realizzati usando tre diversi tipi di precursori polisilossanici. La formazione di pori è stata attribuita alle differenti strutture dei polimeri, che hanno comportato differenti comportamenti durante la pirolisi (maggiore perdita in peso, diminuzione del volume e sviluppo di gas). In tale contesto, precursori polisilossanici sono stati reticolati, ridotti in polvere, setacciati e pressati al fine di ottenere campioni risultanti in monoliti di SiOC poroso, mediante pirolisi. I campioni ceramici cosí ottenuti esibivano valori di resistenza a compressione fino a 37,4 MPa (con una porosità pari a circa il 53% in volume). La pressatura isostatica a caldo ha consentito la formazione di campioni di SiOC(N) aventi piezoresistivitá estremamente elevata, compresa tra 100 e 1700 ad alte temperature (700-1000°C). Utilizzando un precursore polisilazanico, sono state prodotte schiume microcellulari di SiOCN e macrocellulari di SiCN, mediante l’impiego di fillers sacrificali o di un agente schiumante fisico. Le schiume presentavano una porosità prevalentemente interconnessa compresa tra ~60 e 80 vol% ed una resistenza a compressione compresa tra ~1 e 11 MPa. Utilizzando procedimenti simili, sono stati inoltre prodotti campioni monolitici porosi (70 vol%) di PDC contenenti boro. Al fine di produrre componenti ceramici derivati da polimeri, dotati di porosità gerarchica e di elevata area superficiale specifica (SSA), particelle di PMO (Periodic Mesoporous Organosilica) sono state immerse in un polimero polisilossanico schiumato e, mediante pirolisi, sono stati ottenuti campioni monolitici di SiOC permeabili dotati di una elevata SSA, pari a 137 m2/g. Mediante tale metodo, pirolisi catalizzata assistita (CAP), nanofili di nitruro di silicio, di ossinitruro di silicio o di carburo di silicio sono stati formati direttamente durante la pirolisi di campioni monolitici altamente porosi. L’aumento della temperatura di pirolisi ha provocato un aumento nella lunghezza e nella quantità di nanostrutture prodotte. Il meccanismo di crescita dei nanofili dipende dalle condizioni di pirolisi e dal tipo di catalizzatore. La presenza dei nanofili ha permesso di raggiugere elevati valori di SSA nei ceramici macroporosi, compresa tra 10 e 110 m2/g. Le diversità in tali valori sono state spiegate in termini di morfologia e quantità dei nanofili prodotti impiegando due diversi catalizzatori (Co e Fe). L’ablazione superficiale (etching) ad elevate temperature di ceramici di SiCN ha condotto a materiali contenenti carbonio amorfo o grafitico dotati di una struttura gerarchica bimodale dei pori (micro-mesopori con dimensione media dei pori di 3-11 nm) ed elevata SSA, fino a 2400 m2/g. La porosità risultante (dimensione dei pori, PSD e SSA) dipendeva fortemente dall’evoluzione della fase nanostrutturale del materiale PDC, nonché dalle condizioni di etching. La dimensione media dei pori aumentava all’aumentare della temperatura di pirolisi.
Parker, Jeffery Todd. "Bartonella Henselae Inhibits Cellular Apoptotic Regulators to Ensure Survival." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/biology_diss/68.
Повний текст джерелаLAMBENG, NATHALIE. "Differenciation des cellules pc12 et mort cellulaire : role de la voie apoptogene dependante du ceramide et de son inhibition par le ngf et l'amp cyclique." Paris 7, 1999. http://www.theses.fr/1999PA077132.
Повний текст джерелаŠenk, Vít. "Keramické porézní materiály - příprava, struktura a vlastnosti." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229407.
Повний текст джерелаMacKnight, Patrick. "The interaction between ceramide-1-phosphate and Group IVA cytosolic phospholipase A2 and its role in wound healing." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5633.
Повний текст джерелаBUISSON, LEGENDRE NATHALIE. "Controle de la proliferation des keratinocytes humains en culture par les ceramides et les metalloproteinases matricielles (doctorat : biologie cellulaire)." Reims, 2000. http://www.theses.fr/2000REIMM202.
Повний текст джерелаSchneider, Christophe. "Mise en evidence et role du systeme sphingomyeline/ceramide dans les cellules thyroidiennes porcines en culture." Reims, 2000. http://www.theses.fr/2000REIMS003.
Повний текст джерелаJefferson, Grace Elizabeth. "Calcitriol Increases Ceramide, Diacylglycerol, and Expression of Genes Involved in Lipid Packaging in Skeletal Muscle." UKnowledge, 2016. http://uknowledge.uky.edu/khp_etds/31.
Повний текст джерелаBezombes, Christine. "Implication de la voie sphingomyeline-ceramide dans la reponse des cellules de leucemies aigues myeloides aux agents cytotoxiques." Toulouse 3, 1999. http://www.theses.fr/1999TOU30206.
Повний текст джерелаBatocchi, Pierre. "Pile à combustible à céramique conductrice protonique : développement, optimisation des matériaux, réalisation de cellules élémentaires PCFC opérant dans le domaine de température 400-600 °C." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20022.
Повний текст джерелаMaterials components for a Proton Conducting Fuel Cell (PCFC) operating in the 400 – 600 °C temperature range have been optimised. Electrolyte material optimisation involved finding the best compromise between chemical stability and conductivity. BaCe0.9Y0.1O2.95, synthesised by flash combustion, exhibits the highest protonic conductivity (10-2 S.cm-1 at 600 °C) but reacts strongly with CO2. Partial substitution of cerium by zirconium (BCZY) and niobium (BCYN30) led to a significant improvement of the chemical stability without drastic effect on the conductivity (5 × 10-3 S.cm-1 at 600 °C). The aim for the electrodes is to develop materials which exhibit high electronic conductivity, sufficient degree of porosity and good mechanical properties. The approach comprised the development of elaboration strategies (one-step synthesis, use of porogen) that allow the control of microstructure in order to minimize area specific resistances (ASR) at the anode. As in the case of SOFCs, cathodic materials are mixed ionic-electronic conductors (MIEC). Development of composite cathodes MIEC-electrolyte led to a significant reduction of ASR. PCFC single cell tests showed that performance was mostly dependent on electrolyte thickness and composition, and on the characteristics of nanostructured electrodes with controlled architecture and porosity. Optimisation of assemblies led to fuel cells performances of 156 mW.cm-2 at 600 °C
Stanciuc, Ana-Maria. "In vitro evaluation of cell-material interactions on bioinert ceramics with novel surface modifications for enhanced osseointegration." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI053/document.
Повний текст джерелаThe focus of this PhD thesis is the in vitro evaluation of cell-material interactions on bioinert ceramics with novel surface modifications for enhanced osseointegration of orthopaedic and dental implants. Firstly, alumina-zirconia surfaces with different micro-roughnesses obtained by injection moulding were studied. The behaviour of human primary osteoblasts (hObs) obtained from patients undergoing total hip replacements was studied on the different micro-rough ZTA surfaces and on combined micro-/nano-rough surfaces modified by hydrofluoric acid treatment. Micro-roughness alone had minor effects on hOb response while the combination micro-/nano-roughness induced a synergic effect on hOb maturation. This latter surface modification technique opens the way to the fabrication of ceramic acetabular cups with direct implantation capabilities. Secondly, robocasting (a 3D printing technique) was explored for the fabrication of a alumina-zirconia macroporous structures with high reproducibility and control of the architecture. Roughness at different scales was observed for the 3D structures due to the scaffold design and to the low temperature sintering conditions. Osteoblasts were able to attach on the 3D structures but cell retention at long term needs further optimization. Rapid screening of cell-material interactions was the subject of the last part of the thesis. Two different strategies were tested on zirconia: femtosecond laser to produce multiple patterns on a single sample and samples with a roughness gradient by the control of chemical etching time. Stem cell morphology was used as an early marker of cell differentiation lineage. In conclusion, the different surface modification techniques of zirconia and alumina-zirconia surfaces used in the thesis allow the modulation of cell-material interactions by stimulating stem cells osteogenesis and osteoblast maturation
Mahfouz, Rana. "Insulinorésistance musculaire induite par les céramides : étude des mécanismes d'action et de l'implication du transporteur CERT." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066012/document.
Повний текст джерелаObesity and type 2 diabetes are associated with a sedentary lifestyle and a diet rich in fat. Indeed, saturated fatty acids accumulate in non-adipose tissue such as skeletal muscle to generate lipids called ceramides (CER). My thesis project was divided into two parts with the objective to prevent CER to act. We have shown that, depending on the structure of the plasma membrane, CER alter the insulin signaling pathway by targeting PKB, a key insulin signalling protein, via a PKCζ pathway in L6 myotubes and a PP2A pathway in C2C12 myotubes. We also demonstrated that CER affect insulin sensitivity via the PKCζ pathway in human muscle cells. Once CER generated in the endoplasmic reticulum (ER), they are transported to the Golgi by a carrier called CERT to be metabolized into sphingomyelin (SM). Studies have shown that the transformation of CER into SM could be a crucial step to prevent CER to act. In several muscle insulin resistance models, expression of CERT is decreased and we demonstrated the importance of the transport of ceramide from the ER to the Golgi by inhibiting artificially the activity or the expression of CERT. In contrast, overexpression of CERT enhances insulin sensitivity in muscle cells in lipotoxiques conditions. Our results show that CERT plays a crucial role in mechanisms leading to the development of muscle insulin resistance since its presence is essential for maintaining normal traffic of CER between the ER and the Golgi
Mamode, Cassim Adiilah. "Role of the most abundant plant sphingolipids, Glycosyl Inositol Phosphoryl Ceramides GIPCs, in membrane structure and host/pathogen interactions." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0413.
Повний текст джерелаGlycosyl Inositol Phosphoryl Ceramides (GIPCs) are the major sphingolipids of the biosphere. They account for up to 40 mol% of the plasma membranes (PM) of plants and fungi. Since their discovery over 50 years ago, GIPCs remained however almost completely ignored. No data are available on their roles in the structure of biological membranes, on their organization in membrane nanodomains and their interactions with other lipids and proteins. Many questions about plant GIPCs remain unanswered, such as the exact chemical structure of the polar as well as the number sugars grafted; their influence on the thickness of the membrane or on the structure of nanodomains; and also their involvement in host-pathogen interactions in plants. The purpose of this project is to purify and characterize the different classes of plant GIPCs to study their structural roles with phytosterols and phospholipids by biophysical and structural biochemistry methods. This multidisciplinary project will enable the emergence of a new theme and will provide an essential database for understanding the structure of plant PM and among others, their roles in the response against pathogens
Korolkov, Ilia. "Propriétés photoélectriques de vitrocéramiques et cristaux de chalcogénures." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S145/document.
Повний текст джерелаEnergy crisis and global ecological problems are considered as important challenges of nearest future. Eco-friendly and renewable sources of energy are still severely undeveloped and contribute weakly to the energy production. One of the most attractive and promising domains of renewable energy is a solar light harvesting. However, existing solar panels still possess negative quality factor, i.e. their fabrication and maintenance require more energy that they are capable to produce during their life cycle. Despite exponential reduction of the price, solar cells are not efficient enough in terms of light to energy conversion. Recent breakthroughs in material science contributed a lot to the increase of efficiency, however further investigation of novel materials are needed. Here, chalcogenide glassceramics of GeSe2-Sb2Se3-CuI system were studied in details. Within this system various chemical compositions were prepared and analyzed for their structure and photoelectric properties. We found that Sb2Se3 phase, responsible for the appearance of photoelectric effect in glass-ceramics, have a great potential for light harvesting due to its suitable optical properties. In the present work we demonstrated the influence of various dopants on photoelectric properties of Sb2Se3 crystals. We showed a possibility of conductivity type and resistivity tuning of bulk Sb2Se3 crystals in a wide range of values. Thin film devices based on studied bulk compositions were prepared by RF sputtering and characterized structurally and electrically as well. We demonstrated a fully functional thin film solar device based on iodine doped Sb2Se3 and 40GeSe2-40Sb2Se3-20CuI glass-ceramic
Loricourt, Johan. "Réalisation de liaisons céramique-métal par brasage dans une cellule prototype d’électrolyse de la vapeur d’eau à haute température pour la production d’hydrogène." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20037.
Повний текст джерелаSteam electrolysis at high temperature and under pressure with protonic conduction electrolyte is a way to produce hydrogen massively at low cost. To operate, an electrolysis cell must be hermetic especially between the anodic compartment (O2 and H2O) and the cathodic one (H2). Thus, ceramic to metal assemblies are needed, either to insert the electrolyte (perovskite-metal junction) or to realize power supply (alumina-metal junction).Considering the operating conditions (873°K, 725 PSI, steam), only a brazing process is possible to realize strong and hermetic junctions.The evaluation of corrosion process under steam pressure has enabled to select a metallic component and a brazing alloy for this application, and has shown that specific alloys are needed.The studies of ceramics metallization by PVD to assure the brazing alloy wetting throughout the brazing process have shown that a barrier diffusion was necessary to avoid the dissolution of coatings when the brazing alloy become liquid.After wetting experimentations of the chosen brazing alloy over the metalized ceramics and the metallic substrate, ceramic to metal assemblies have been optimized in applying the experimental design methodology on standard samples (ASTM).The whole results have enabled to develop hermetic ceramic to metal assemblies having good mechanical properties (Rm = 8700 PSI at 300°K)
Santos, Cécile. "Conception, synthèse et évaluation de nouveaux inhibiteurs du transport de céramide : vers de nouveaux agents de sensibilisation des cellules cancéreuses chimiorésistantes." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30238/document.
Повний текст джерелаDuring its metabolism, ceramides, produced de novo in the endoplasmic reticulum, are transported to the Golgi complex to be converted into sphingomyelin. The main way of this transport involves the cytosolic CERT protein (Ceramide Transfer). Overexpression of CERT, responsible for a diminution of intracellular level of proapoptotic ceramide, is associated with the phenomenon of resistance to chemotherapeutic agents in several tumor cell lines. The CERT inhibition allows to resensitize these cell lines to anticancer drugs. Yet, only a single family of inhibitors is known to date: HPAs. Located at the C-terminal region of the protein, the START domain contains the binding site of ceramide necessary for the transport activity of CERT. Based on crystallographic structures, a method for the identification of new CERT ligands, combining in silico and in vitro tools, was developed. Jaspine B, HPAs analogs and iminosugars were identified as potential antagonists using this method. Some of these compounds were synthesized and evaluated in vitro. Fluorescent probes of jaspine B were designed for a better understanding of it mechanism of action. In parallel, an in vitro HTR-FRET binding assay was developed, allowing the high-throughput screening of the National Essential Compound Library
Ponsot, Inès. "Glasses and Glass-Ceramic Components from Inorganic Waste and Novel Processing." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424636.
Повний текст джерелаGrazie alle regole e normative ambientali europee istituite, il riciclaggio dei rifiuti è diventato una problematica sempre più rilevante. Per gli impianti di produzione, in particolare quelli che producono rifiuti pericolosi, le spese connesse allo smaltimento sono drasticamente aumentate negli ultimi decenni. Nel lavoro proposto, vari rifiuti, pericolosi o no, vengono utilizzati per elaborare diverse composizioni di vetroceramiche. Si distinguono rottami di vetro della produzione di finestre, di contenitori farmaceutici e di tubi catodici. I rifiuti non vetrosi invece sono calce esausta da residui di sistemi di filtrazione di fumi, scorie metallurgiche da leghe ferrose e non e ceneri da inceneritori. E' presentata nel presente lavoro la ricerca di un metodo di trattamento ad alta temperatura (minima 800 ° C) efficace per stabilizzare chimicamente il prodotto finale, tramite i diversi processi di sinterizzazione diretta, sinter-cristallizzazione e vetrificazione. Sono stati studiati gli effetti di ogni rifiuto sulle proprietà meccaniche del prodotto finale, ma anche le nuove funzionalità ottenute attraverso le sinergie risultanti dalla loro miscela. Miscele calibrate hanno permesso di sviluppare prodotti interessanti per applicazioni edilizie moderne, come le piastrelle porose e pannelli leggeri destinati all’isolamento.
Ehret, Christophe. "Synthèse de nouveaux ligands du récepteur CD1d : applications à la vaccination anti-tumorale." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00767140.
Повний текст джерелаPetit, Clémence. "Etude des propriétés mécaniques de matériaux cellulaires par la tomographie aux rayons X et par modélisation par éléments finis." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0130/document.
Повний текст джерелаCellular materials are highly porous systems for which two scales are mainly important: the mesostructure and the microstructure. The mesostructure corresponds to the architecture of the materials: distribution of solid phase “walls” and macroporosity and can be characterized by X-ray tomographic low resolution images. The link between the architecture of the materials and the mechanical properties has been frequently studied. The microstructure refers to the characteristics of the solid phase. Its microstructural features (presence of a secondary phase or of defects due to the sintering) can have a strong influence on the macroscopic properties. The aim of this work is to link the morphological and microstructural features of metallic and ceramic based cellular materials and their mechanical properties thanks to X-ray tomography and finite element modelling. A new method combining X-ray tomography at different resolutions, image processing and creation of finite element modelling enabled to take into account some microstuctural features of the cellular samples. Four different cellular materials were studied as model materials: aluminium foam fabricated by a liquid state process, cobalt periodic structures made by additive manufacturing, β-TCP porous samples fabricated by conventional sacrificial template processing route and hydroxyapatite/β-TCP composites made by additive manufacturing (robocasting). The metal based materials were provided by colleagues while the ceramic based porous materials were fabricated in the frame of the current study. For each type (metals or ceramics), a stochastic and a regular structure have been compared. For implementing the multiscale method developed in this work, the samples were firstly scanned in a so called “local” tomography mode, in which the specimen is placed close to the X-ray source. This allowed to reconstruct only the small irradiated part of the sample and to obtain a magnified image of a subregion. These images enable to observe some details which are not visible in lower resolution. Different image processing steps were performed to generate low resolution images including microstructural features imaged at high resolution. This was done by a series of thresholding and scaling of the high resolution images. The result of these processing steps was an image of the initial sample. Then, in situ mechanical tests were performed in the tomograph to follow the deformation of the sample at low resolution. The above mentioned initial images were used to produce finite element meshes. Special Java programs were adapted to create finite element input files from initial images and meshes. The initial images containing information about the solid phase, the images from the mechanical tests and the finite element models were combined to explain the mechanical behaviour of the sample by linking the experimental damage locations in the sample and the simulated stress concentration sites
ESPINOSA, DE LOS MONTEROS MARIA DOLORES ARACELI. "Contribution a l'etude des oligodendrocytes in vitro." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13008.
Повний текст джерелаRicard, Jérôme. "Etude du développement des kystes de Toxoplasma gondii in vitro : rôle de la voie de signalisation du TNF-[alpha] de la cellule hôte : rôle de la phospholipase C-spécifique de la phosphatidylcholine du parasite." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10196.
Повний текст джерелаFayeulle, Dominique. "Elaboration et étude de révêtements céramiques à sous-couche d'accrochage cellulaire pour la protection chimique et thermique de composants de turbomachines." Paris, ENMP, 1989. http://www.theses.fr/1989ENMP0149.
Повний текст джерелаBakar, Joudi. "Etude de la biosynthèse lipidique au cours de la différentiation kératinocytaire en lien avec l’intégrité de la fonction barrière cutanée Comprehensive characterization and simultaneous analysis of overall lipids in reconstructed human epidermis using NPLC/HR-MS n: 1-O-E (EO) Cer, a new ceramide subclass Biomolecular modifications during keratinocyte differentiation: Raman spectroscopy and chromatographic techniques." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASF018.
Повний текст джерелаThe keratinocytes differentiation is accompanied by profound modifications of the lipid composition of the cell contents to form at the terminal differentiation stage the intercorneocyte cement (lipid matrix) responsible for the skin barrier function. Ceramides are the major lipid class of the epidermis. This class is very complex, it self is divided into subclasses which differ in their structural micro-heterogeneity. The aim of this work was to develop an analytical methodology to study the biosynthesis of these epidermal lipids during keratinocyte differentiation. On this subject, two analytical techniques were used: 1) Normal Phase-High Performance Liquid Chromatography coupled with High Resolution Mass Spectrometry NP-HPLC/HR-MSⁿ. A method has been developed in order to separate the lipid classes of different polarity in a one single run and to characterize the fine structures of lipids in particular the structural micro-heterogeneity of ceramides. 2) Raman Microspectroscopy, which provides information at levels of molecules and of tissues. Pseudo-color spectral images have the ability to better follow the evolution of lipids during differentiation and to provide information on the lipid organization of the Stratum Corneum. Three cellular models were used to achieve our objectives: 1) A 2D cell model: for monitoring the differentiation from the early stages (basal layer). This model made it possible to provide information at the cellular level by Raman imaging. It was also used to establish the first developments in NP-HPLC/HR-MSⁿ. 2) A healthy 3D reconstructed human model of epidermis, better mimicking the environment in vivo: for monitoring differentiation from Stratum Granulosum (SG) and up to the formation of Stratum Corneum (SC) multilayers. This model allowed to provide information at the tissue level (epidermal layers). In addition, it is on this model that all the in-depth characterization of ceramides was carried out, taking into account all the structural heterogeneities. 3) An altered 3D human reconstructed epidermis model: to illustrate the suitability of the NP-HPLC/HR-MSⁿ method in order to highlight the impact on the lipid profile of a targeted enzymatic deficit and to understand the potential effect of an active molecule. The major results obtained from the experimental work are as follows: 1) The development of relevant analytical tools in the elucidation of complex lipid mixtures and their evolution at the cellular or tissue level. 2) The innovative application of Raman Microspectroscopy at the level of the keratinocyte cell (2D cell model): several molecular modifications within the cell were observed and in particular between days 9 and 13 of differentiation indicating the passage between SG and SC. 3) The identification for the first time in the literature of two new subclasses of ceramides (1-OE (EO) Cer and A-1-O (EO) Cer) in the healthy human reconstructed epidermis model but also in the human SC, from data provided by the developed method in NP-HPLC/HR-MSⁿ. 4) Demonstration of a disruption of the lipid profile at maturation on an altered reconstructed human epidermis model. All of these results have been able to provide a better understanding of lipid metabolism during keratinocyte maturation, in very detail at the molecular level, which would allow a more reasoned understanding of the physiological or pathological disturbances of the skin barrier function
Monge, Madeleine. "Séquence d'apparition du galactosylcéramide, de la protéine de Wolfram, de la protéine basique encéphalitogène et du protéolipide de Folch dans l'oligodendrocyte et dans la myéline au cours de la myélinisation chez la souris : étude comparative de la différenciation de l'oligodendrocyte in vivo and in vitro." Paris 6, 1986. http://www.theses.fr/1986PA066245.
Повний текст джерелаStorm, Johannes. "Entwicklung und Bewertung von effizienten Berechnungskonzepten für keramische Filter." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2017. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-218483.
Повний текст джерелаRozié, Alexandrine. "Criblage de petites molécules d'intérêt thérapeutique et recherche de leur mécanisme d'action." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30246.
Повний текст джерелаThe identification of the mechanism of action of small bioactive molecules allows (i) to reveal unexpected pharmacological targets against which new therapeutic molecules that can be developed, (ii) to discover original modes of action that can inspire the development of new drugs, and (iii) to develop biomarkers of response to these treatments. The objective of my thesis was to apply several target identification approaches to small molecules, either new, from a phenotypic screen, or already known but the mechanism of action of which was not identified. In a first part of my work, a phenotypic screen was developed in order to identify in the " Chimiothèque Nationale Essentielle ", new sensitizers to the prototype of a family of DNA-damaging anti-cancer agents, camptothecin (CPT). CPT is a poison of topoisomerase I, inducing a particular type of double-strand DNA breaks (DSB) associated with replication forks. This screen led to the identification of a new sensitizer that we named Shuri1. We have established that Shuri1 induces DSB selectively in replicating cells. We demonstrated that Shuri1 behaves as an inhibitor of the CHK1 protein kinase involved in the signaling of DNA damage. Accordingly, some mutations conferring resistance to a specific CHK1 inhibitor also confer resistance to Shuri1. In a second part of my thesis, I studied the mechanism of action of Jaspine B, a natural molecule derived from marine sponges that exhibits strong cytotoxicity against different human solid tumor cell lines. Previously, several mechanisms have been proposed for Jaspine B, but none accounts for the cellular effects of this molecule. In collaboration with Yves Génisson's team at the SPCMIB in Toulouse, a clickable analogue of jaspine B was synthesized and was localized by cell microscopy as aggregates at the endoplasmic reticulum (ER). Using lipidomics, functional genomics and real-time imaging, we have established a model of the Jaspine B mechanism of action in cancer cells. My work supports that Jaspine B behaves as a prodrug that is bioactivated by one of the ceramide synthases, enzymes involved in ceramide biosynthesis. The N-Acylated Jaspine B thus produced at the ER accumulates as aggregates responsible for the permeabilization of the ER and of the cell leading to cell death. We further established that this mechanism also explains the cytotoxic effects of another lipid produced by marine sponges
Cree, Duncan. "Production and characterization of three-dimensional, cellular, Metal-filled ceramics." Thesis, 2009. http://spectrum.library.concordia.ca/976524/1/NR63360.pdf.
Повний текст джерелаDesai, Dhanashri Tejpal. "3D-Printing of Lunar Soil Simulant by Direct-Extrusion method." Thesis, 2023. https://etd.iisc.ac.in/handle/2005/6172.
Повний текст джерелаWronowska, Weronika. "Computational models of response to cellular stress factors." Doctoral thesis, 2019. https://depotuw.ceon.pl/handle/item/3595.
Повний текст джерелаNiniejsza rozprawa doktorska dotyczy tematyki formalnego modelowania procesów biologicznych stanowiących elementy odpowiedzi na warunki stresowe. Zaburzenia tych mechanizmów często leżą u podłoża rozwoju chorób nowotworowych i neurodegeneracyjnych. W rozprawie prezentuję dwa formalne modele opisujące procesy molekularne odpowiadające wybranym poziomom funkcjonowania komórek. Poziom metaboliczny reprezentuje model komórkowego metabolizmu sfingolipidów, z kolei model odpowiedzi komórki na warunki stresu termicznego, stanowi przykład formalnego modelu regulacji ekspresji genów. Ponadto w rozprawie zaproponowałam metodę obliczeniową pozwalająca szacować liczność podpopulacji komórek różniących się odpowiedzią transkryptomiczną na czynnik stresowy. Metoda ta pozwala również wnioskować na temat aktywacji różnorodnych ścieżek sygnałowych w odpowiedzi na czynniki stresu komórkowego. Opracowany przeze mnie formalny model metabolizmu sfingolipidów jest pierwszym w literaturze modelem zawierającym wszystkie elementy kluczowe dla metabolizmu tych bioaktywnych lipidów w komórkach ludzkich. Ponad to model umożliwia śledzenie ich zachowania w zależności od analizowanego organellum komórkowego. Co istotnie opisywany model może być wykorzystywany do badania zmian metabolicznych towarzyszących chorobom neurodegeneracyjnym. W tym kontekście elementy modelu zostały wykorzystane do opracowania ilościowego systemowego modelu farmakologicznego dla choroby Alzheimera przez firmę CERTARA. Następnie w rozprawie opisuję badania laboratoryjne wykonane w celu walidacji modelu metabolizmu sfingolipidów. Wyniki tych badań, w szczególności analiza wpływu ceramidu (bioaktywnego sfingolipidu) na nowotworowe komórki nerwowe (neuroblastoma) pozwoliły na opracowania innowacyjnej metody badania heterogeniczności reakcji komórek na czynnik stresowy. Metoda ta, nazwana MPH (ang.Molecular Process Heterogeneity), pozwala na rozłożenie macierzy ekspresji w taki sposób, że otrzymujemy informację o (i) proporcjach badanych subpopulacji w danej próbce oraz (ii) wzorcach transkrypcji specyficznych dla każdej subpopulacji. Zaproponowana metoda pozwoliła na weryfikację hipotez dotyczących cytoprotekcyjnej roli PJ34, czyli inhibitora polimerazy poli (ADP-rybozy) – PARP na komórki nerwiaka zarodkowego linii linii SH-SY5Y traktowane ceramidem. Drugim formalnym modelem, opisanym w niniejszej rozprawie jest model szoku termicznego (ang.Heat Shock Response; HSR) w komórkach HeLa. Pozwala on na badanie mechanizmu regulacji ekspresji genów kodujących białka z rodziny HSP w szczególności HSP70, będącego chaperoniną kluczową dla ochrony komórek przed efektami cieplnej denaturacji białek. W modelu przedstawiłam pętlę regulatorową działającą na zasadzie ujemnego sprzężenia zwrotnego obejmującą interakcje krytyczne dla odpowiedzi komórki na szok termiczny. Schemat biochemiczny modelu składa się z dwunastu reakcji, które zostały przekształcone w układ równań różniczkowych zwyczajnych. Zachowania modelu badałam między innymi metodą analizy wrażliwości modelu co pozwoliło na wskazanie kluczowych reakcji, których zaburzenie propaguje szum na pozostałe interakcje. Nazwa HSR sugeruje, że odpowiedź komórki wywołana jest stresem cieplnym, jednakże białka z grupy HSP uczestniczą w reakcji na najrozmaitsze czynniki stresowe. Ich udział jest kluczowy dla rozwoju zarówno chorób nowotworowych jak i neurodegeneracyjnych, co więcej raportowano istnienie powiązań między aktywnością HSP70, a ścieżkami metabolizmu sfingolipidów. Z uwagi na ogromną złożoność i wielowymiarowość mechanizmów komórkowej reakcji na stres, zastosowanie podejścia systemowego wydaje się być jedyną drogą mogącą przybliżyć nas do zrozumienia i opisania zasad molekularnej reakcji na stres. Wykorzystanie modeli obliczeniowych i symulacji komputerowych pozwala na wgląd w naturę tych złożonych systemów.
Yu, Hiu Ming (Bosco). "The Architectural Optimization of Stretch-formed Ceramic-aluminum Microtruss Composites." Thesis, 2012. http://hdl.handle.net/1807/33600.
Повний текст джерелаYang, Cheng-Lin, and 楊承琳. "Trivalent Chromium Induces Autophagy by Activating Sphingomyelin Phosphodiesterase 2 and Increasing Cellular Ceramide Levels in Renal HK2 Cells." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/92502930268140989690.
Повний текст джерела國立中興大學
生物醫學研究所
105
Recently, autophagy has emerged as a major cell response to metabolic stress, drug toxicity, environmental pollutants and lipogenetic disturbance. Most of effort has focused on the proteins and protein interaction in autophagosome formation. However, the role of lipids has not been investigated. In this study, we examined the role of autophagy in the initiation of lipid increases in renal epithelial HK2 cells. We found that trivalent chromium [Cr (III)] induced autophagy by activating sphingomyelin phosphodiesterase 2 (SMPD2). SMPD2 increases levels of ceramide and other lipids. Our recent studies found that signals of ceramide overlapped with LC3 demonstrated by confocal immunofluorescence microscopy study, suggesting that ceramide might play an important role in the formation of autophagosome. In conclusion, our data indicate that Cr (III) induces autophagy via structural aberration of organelle membrane, in particular by the increase of lipid compositions in addition to autophagy-associated proteins.
Saha, Bhaskar Prasad. "Processing Of Zirconia Based Honeycombs And Evaluation Of Thermo Mechanical Properties." Thesis, 2008. https://etd.iisc.ac.in/handle/2005/818.
Повний текст джерелаSaha, Bhaskar Prasad. "Processing Of Zirconia Based Honeycombs And Evaluation Of Thermo Mechanical Properties." Thesis, 2008. http://hdl.handle.net/2005/818.
Повний текст джерела