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Villarreal, Larrauri Alejandro. « Analysis and modeling of ex-vessel underwater cooling processes of debris bed and molten corium pool in interaction with concrete ». Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0022.
Texte intégralRésumé :
En cas d'accident grave avec fusion du cœur, le magma surchauffé constitué d'acier et de combustible fondu, appelé corium (T> 2 500 K), peut menacer l'intégrité de la cuve du réacteur, puis du bâtiment de confinement, si le refroidissement du corium n’est pas assuré. La capacité de refroidissement en situation hors-cuve, par l’injection d’eau et pénétration de celle-ci dans le corium en surface supérieure, est étudiée pour deux configurations attendues : le lit de particules et bain de corium. La seconde configuration est liée à la situation d’interaction corium-béton (ICB) où une croûte se forme en face supérieure en contact avec l’eau, puis est soumise à une fracturation à cause des effets thermiques dans cette croûte. L’enjeu est de caractériser l’efficacité d’une éventuelle pénétration de l’eau dans la croûte. La première configuration peut intervenir en particulier dans deux situations suite à une fragmentation du corium dans l’eau : lors de l’éjection hors de la cuve, ou suite à des périodes d’éjection à travers la croute en phase d’ICB par entraînement du corium par des gaz issus de l’ablation du béton. Les phénomènes de pénétration de l’eau dans le corium sont examinés par une analyse approfondie des résultats des expériences disponibles, par la mise au point d’un modèle analytique 1D et par la modification et l’utilisation du code de thermohydraulique multiphasique multi-fluides (CMFD) MC3D. L’analyse 1D permet de mieux comprendre les détails de l’écoulement diphasique dans la matrice poreuse et conduit à proposer un modèle simplifié de pénétration de l’eau, avec des relations correspondantes applicables pour les deux configurations d'intérêt. Par ailleurs, le développement et l’impact d’instabilités au front de pénétration sont étudiés avec des simulations 2D avec MC3D, illustrant le rôle important de la température initiale du lit et sa perméabilité sur la vitesse de pénétration du front, et sur l’apparition des instabilités. Le modèle analytique est alors étendu à une configuration à deux zones (une zone soumise à un écoulement diphasique en contre-courant et une zone monophasique dans laquelle la vapeur surchauffée traverse) pour analyser plus en détail l’impact des hétérogénéités de progression du front sur les flux thermiques extraits. Le mécanisme de pénétration de l’eau dans les croûtes est discuté. L’analyse indique de forts effets de bords sur les processus de fracturation dans les essais SSWICS (Argonne Nat. Lab.), dédiés à ce phénomène. Les conclusions des travaux précédents sur l’efficacité du phénomène ne peuvent dès lors être confirmées du fait des fortes incertitudes sur les processus de fracturation, très sensibles aux propriétés mécaniques du corium, très mal caractérisées. Finalement, les modèles sont appliqués aux situations réelles impliquant la présence de la puissance résiduelle. Pour les lits de débris, les flux extraits et les capacités de refroidissement sont moindres qu’avec l’utilisation du critère simplifié de « flux d’assèchement »In the case of a hypothetical nuclear severe accident with partial or extensive core meltdown, the superheated magma made of molten steel and fuel, called corium (T > 2500K), may threaten the integrity of the reactor pressure vessel and subsequently the reactor containment building, if long-term corium coolability is not assured. The coolability by water injection and successive water penetration into the corium through the upper surface is analyzed for two expected configurations: particle bed, and corium pool overlaying the concrete. The second configuration is linked to the situation of Molten Corium-Concrete Interaction (MCCI), where a crust is formed in the upper corium surface when it comes into contact with water and is later subjected to thermal stresses that lead to its fracturing. The challenge is to characterize the effectiveness of extracting heat by the possible water penetration into the crust. The first configuration can be expected in two different situations: melt fragmentation coming from the rupture of the reactor pressure vessel and expulsion of the corium, or during melt eruption episodes through the corium crust during MCCI via corium entrainment by the concrete decomposition gases. The phenomena linked to the water penetration into the corium for these two configurations are examined through an in-depth analysis of the available experimental results, by the development of an analytical model and finally through the modification and use of the Computational Multi-Fluid Dynamics (CMFD) code MC3D. One dimensional analysis conducts to a better understanding of the minutia of the two-phase countercurrent flow through the porous media and leads the proposal of a simplified heat flux model for the water penetration with corresponding relations applicable for both configurations of interest. Furthermore, the development and the impact of penetrating front instability are studied with the help of 2D MC3D simulations, which show important effects of the initial temperature and the permeability of the corium configuration on the penetration front velocity and appearance of the instabilities. The analytical model is extended to a pseudo-two-dimensional two-zone configuration (with one zone subjected to a two-phase countercurrent flow and another through which monophasic superheated vapor flows) to analyze in greater detail the impact of the penetrating front heterogeneity over the extracted heat flux. The mechanism of water penetration through a fractured crust is revisited. The analysis indicates strong border effects in the SSWICS tests (Argonne National Laboratories) dedicated to the study of this phenomenon. The conclusions of precedent studies on the efficiency of the phenomena could not, therefore, be confirmed due to important uncertainties over the process of fracturing, overly sensitive to the mechanical properties of corium, which in turn are not properly characterized. Finally, the models, and simulations, are applied to real accidental scenarios, including the presence of residual power. For the debris bed, the extracted heat flux, and the cooling capabilities are less than those found using the simplified dry-out heat flux criteria
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Fillman, Benny. « System studies of MCFC power plants ». Licentiate thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-419.
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Chen, Kenway. « MCAD - ECAD integration : constraint modeling and propagation / ». Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26484.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Schaefer, Dirk; Committee Member: Panchal, Jitesh; Committee Member: Paredis, Chris; Committee Member: Rosen, David; Committee Member: Yoder, Douglas. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Bodén, Andreas. « The anode and the electrolyte in the MCFC ». Doctoral thesis, KTH, Kemiteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4382.
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A goal of the Swedish government is to increase the usage of renewable fuels and biomass-based fuels. Fuel cells, and especially the MCFC, are useful for these types of fuels. The Swedish market may benefit from the MCFC in two ways: increased efficiency of the biofuels and also utilisation of produced heat in district heating. Most of the commercial MCFC systems today are optimised for use with methane. The possibility to utilise biomass in Sweden makes it important to study how the MCFC may be adapted or optimised for good performance and low degradation with gas produced from biomass or other renewable fuels. This thesis is focused on methods that may be used to investigate and evaluate MCFC electrodes and electrolytes with renewable fuels i.e. CO2-containing gases. The methods and results are both experimental and mathematically modelled. The objectives of this thesis are to better understand how the performance of the anode is dependent on different fuels. Anode kinetics and the water-gas shift reaction have been investigated as well as the possibility to increase cell lifetime by increasing the initial electrolyte amount by having the anode as a reservoir. The effect of segregation of cations in the electrolyte during operation has also been studied. It was found that if the gas composition at the current collector inlet is in equilibrium according to the water gas-shift reaction the gas composition inside the electrode is almost uniform. However, if the gas is not in equilibrium then the concentration gradients inside the current collector have a large effect on the gas composition inside the electrode. The conversion of the gas in the gas flow channels according to the water-gas shift reaction depends on the gas flow rate. For an anode used in a gas mixture of humidified hydrogen and carbon dioxide that are not in equilibrium some solubility of Ni in a (Li/Na)2CO3 mixture was found. To have the anode act as an electrolyte reservoir to prolong cell lifetime the anode pore size should be carefully matched with that of the cathode and a bimodal pore-size distribution for the anode is preferable to have as good performance as possible for as large electrolyte filling degree interval as possible. Modelling results of segregation of cations in the electrolyte during operation indicate that the electrolyte composition changes during operation and that the lithium ions are enriched at the anode for both types of electrolyte used for the MCFC. The electrolyte composition changes are small but might have to be considered in long-time operation. The results from this thesis may be used to better understand how the MCFC may be used for operation with renewable fuels and how electrodes may be designed to prolong cell lifetime.Ett av den svenska regeringens mål är att öka användandet av förnyelsebara bränslen och bränslen från biomassa. Bränsleceller och framförallt MCFC är användbara för dessa typer av bränslen. Den svenska marknaden kan dra fördelar av MCFC på två sätt; ökad bränsleutnyttjandegrad och utnyttjande av producerad värme för fjärrvärme. De flesta kommersiella MCFC-systemen idag är optimerade för användning av metan. Möjligheten att använda biomassa på den svenska marknaden gör det viktigt att studera hur MCFC kan anpassas eller optimeras för bra prestanda och låg degradering för användning med gas från biomassa eller andra förnyelsebara bränslen. Fokus i denna avhandling är på metoder som kan användas för att undersöka och utvärdera MCFC-elektroder och -elektrolyter med förnyelsebara bränslen, dvs. gaser innehållande CO2. Metoderna och resultaten är både experimentella och matematiskt modellerade. Målet med denna avhandling är att bättre förstå hur anodens prestanda beror på användningen av olika bränslen. Anodens kinetik och vattengasskiftreaktionen har studerats liksom möjligheten att förlänga cellens livstid genom att öka den initiala mängden elektrolyt medelst användning av anoden som reservoar. Effekten av segregation av katjoner i elektrolyten under last har också undersökts. Om gassammansättningen är i jämvikt enligt vattengasskiftreaktionen vid inloppet till strömtilledaren kommer gassammansättningen att vara nära uniform inuti elektroden. Om ingående gas inte är i jämvikt kommer stora koncentrationsgradienter uppkomma i strömtilledaren och påverka gassammansättningen i elektroden. Omsättningen med avseende på vattenskiftreaktionen av gasen i flödeskanalen verkar vara beroende av gasens flödeshastighet. För en anod som används i en uppfuktad blandning av vätgas och koldioxid som inte är i jämvikt befanns det att Ni har en viss löslighet i (Li/Na)2CO3. För att kunna använda anoden som reservoar för elektrolyt för att förlänga livstiden för MCFC skall anodens porstorleksfördelning överensstämma med katodens och ha en bimodal porstorleksfördelning för att ge en tillräckligt god prestanda i ett så stort elektrolytfyllnadsgradsintervall som möjligt. Modelleringsresultat för segregering av katjoner i elektrolyten under drift visar att litiumjoner anrikas i anoden för båda typerna av elektrolyt som används i MCFC. Elektrolytkoncentrationsförändringarna är små men kan behövas tas i beaktande vid långa driftstider. Denna avhandlings resultat kan användas för att bättre förstå hur MCFC skall anpassas för drift med förnyelsebara bränslen och hur elektroder kan utformas för att förlänga livstiden.
QC 20100630
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Bodén, Andreas. « The anode and the electrolyte in the MCFC / ». Stockholm : Kemiteknik Chemical and Engineering and Technology, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4382.
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Wilcox, Adam C. « ECAD to MCAD Interoperability for Automated Enclosure Design ». Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2690.pdf.
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Law, Tsz Hong. « The effects of a MCTD in canine epilepsy ». Thesis, Royal Veterinary College (University of London), 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.766311.
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Dong, Liang. « Novel optical fibre devices based on MCVD method ». Thesis, University of Southampton, 1992. https://eprints.soton.ac.uk/404723/.
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In this thesis, several new optical fibre devices are described. These devices are based on fibres with special structures or materials, fabricated by the MCVD technique. Light propagation and intermodal coupling in twin-core (TC) fibres are investigated both theoretically and experimentally. A cascaded TC fibre filter is demonstrated and so are TC fibre intermodal couplers using both mechanical gratings and fibre acoustic flexural waves, which can be used as filters, wavelength-division multiplexing (WDM) taps and frequency shifters. Photosensitivity in both transition-metal-doped fibre and cerium-doped fibre with applications for making fibre in-core gratings are also studied. UV-induced absorption and refractive index change are investigated. A large absorption change occurs when fibre is exposed to pulsed UV. The fibre IR loss eventually recovers to its original level. The UV-induced refractive index change in cerium fibre is found to be the same order of magnitude as that reported in germanosilicate fibres. Some other devices and effects, including a gold-implanted fibre polariser, excitation poling in second harmonic generation and a spatial model converter, are also studied. The gold-implanted polariser is much easier to be massproduced and spliced to an ordinary fibre with a low loss than its liquid-metal-implanted counterpart. Excitation poling gives an improved efficiency in second harmonic generation. The spatial model converter provides an easy low-loss connection for waveguides with different spatial modes.
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Bednarz, Marc. « Mechanistische Untersuchung und Modellierung der Kathodenreaktion in Karbonatbrennstoffzellen (MCFC) ». [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=968348890.
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Spitezki, Henri. « Contribution à l'étude du management stratégique : le modèle MCVD ». Paris 1, 1998. http://www.theses.fr/1998PA010012.
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L'objet de cette thèse est d'appréhender qualitativement les effets macroéconomiques des allocations chômage. Deux questions sont plus particulièrement au cœur de nos préoccupations : la comparaison positives des régimes d'assurance et d'assistance chômage, qui est au cœur de la deuxième partie, et la détermination de la générosité globale des allocations chômage, qui est au cœur de la troisième partie. La première partie de la thèse dresse un état des lieux des contributions existantes. Dans le premier chapitre, nous nous concentrons sur des modèles ou ce sont les comportements des individus qui déterminent leur probabilité d'être au chômage, alors que dans le chapitre 2, le chômage est due à la formation non concurrentielle des salaires. Dans les deux autres parties de la thèse, nous nous plaçons dans le cadre d'un modèle de négociations salariales dynamiques ou l'effort de recherche d'emploi des individus n'intervient pas. Dans le chapitre 3, nous montrons que la dégressivité des allocations chômage peut aggraver le taux de chômage d'équilibre. Dans le chapitre 4, nous montrons que l'indexation de l'assurance chômage sur les derniers salaires négociés accroit la pression salariale et le chômage. Le chapitre 5 détermine alors le niveau des allocations chômage qui maximise différents critères de bien-être. Le ratio de remplacements optimal pour les travailleurs au chômage est supérieur à celui des travailleurs employés, qui est lui-même supérieur à celui qui maximise la somme des utilités des travailleurs. Enfin, le ratio de remplacement qui maximise les profits est nul. Le dernier chapitre de la thèse introduit un modèle de vote afin de comprendre pourquoi les agents choisissent un niveau d'allocations chômage qui entraine un niveau de chômage positif. On met alors en évidence une relation négative entre le taux de chômage et le ratio de remplacement des allocations chômageIn this dissertation, I try to give a better qualitative understanding of the macroeconomic effects of unemployment benefits. The two most important question i ask is the comparison of the positive properties of unemployment insurance and of unemployment assistance, which constitute the second part of the dissertation, and the determination of the global generosity of unemployment benefits, which constitute the third part of the dissertation. The first part propose a survey of the literature. In the first chapter, i focus on models where the probability of being unemployed depends only on individuals' behaviour while in the second chapter, unemployment arises because of imperfect competition in the wage setting. In the two other parts of the dissertation, i use a dynamical wage bargaining model in which search effort does no matter. In chapter 3, i show that the digressiveness of unemployment benefits might increases the unemployment rate. In chapter 4,1 show that indexing unemployment benefits on past wage earned increases the wage pressure and the equilibrium unemployment. Chapter 5 looks at the level of the replacement ratio that maximises different steady-state welfare criterions. The optimal replacement ratio according to unemployed workers is higher than the one according to employed workers, which is itself higher than the one according to the sum of utility of every workers. At last, the replacement ratio that maximises profits is null. The last chapter introduces a voting process on the level of the replacement ratio so as to understand why rational agents supports levels of replacement ratio that leads to a positive level of the unemployment rate. We prove the existence of a negative relation between the unemployment rate and the replacement ratio
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He, Wei. « Mathematical Modeling of Therapies for MCF7 Breast Cancer Cells ». Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103967.
Texte intégralRésumé :
Estrogen receptor (ER)-positive breast cancer is responsive to a number of targeted therapies used clinically. Unfortunately, the continuous application of any targeted therapy often results in resistance to the therapy. Our ultimate goal is to use mathematical modelling to optimize alternating therapies that not only decrease proliferation but also stave off resistance. Toward this end, we measured levels of key proteins and proliferation over a 7-day time course in ER-positive MCF7 breast cancer cells. Treatments included endocrine therapy, either estrogen deprivation, which mimics the effects of an aromatase inhibitor, or fulvestrant, an ER degrader. These data were used to calibrate a mathematical model based on key interactions between ER signaling and the cell cycle. We show that the calibrated model is capable of predicting the combination treatment of fulvestrant and estrogen deprivation. Further, we show that we can add a new drug, palbociclib, to the model by measuring only two key proteins, c-Myc and hyperphosphorylated RB1, and adjusting only parameters associated with the drug. The model is then able to predict the combination treatment of estrogen deprivation and palbociclib. Then we added the dynamics of estrogen concentration in the medium into the model and extended the short-term model to a long-term model. The long-term model can simulate various mono- or combination treatments at different doses over 28 days. In addition to palbociclib, we add another Cdk4/6 inhibitor to the model, abemaciclib, which can induce apoptosis at high concentrations. Then the model can match the effects of abemaciclib treatment at two different doses and also capture the apoptosis effects induced by abemaciclib. After calibrating the model to these different treatment conditions, we used the model to explore the synergism among these different treatments. The mathematical model predicts a significant synergism between palbociclib or abemaciclib in combination with fulvestrant. And the predicted synergisms are verified by experiments. This critical synergism between these Cdk4/6 inhibitors and endocrine therapy could reflect the reason that Cdk4/6 inhibitors achieve pronounced success in clinic trails. Lastly, we used protein biomarkers (cyclinD1, cyclinE1, Cdk4, Cdk6 and Cdk2) and palbociclib dose-response proliferation assays to assess the difference between mono- and alternating therapy after 10 weeks of treatments. But neither the protein levels nor palbociclib dose-response show significant differences after 10 weeks of treatment. Therefore, we cannot conclude that alternating therapy delays palbociclib resistance compared with palbociclib mono-treatment after 10 weeks. Longer term experiments or other methods will be needed to uncover any difference. However, in this research we showed that a mechanism-based mathematical model is able to simulate and predict various effects of clinically-used treatments on ER-positive breast cancer cells at different time scales. And this mathematical model has the potential to explore ideas for potential drug treatments, optimize protocols that limit proliferation, and determine the drugs, doses, and alternating schedule for long term experiments.Doctor of Philosophy
Estrogen receptors are proteins found inside breast cancer cells that are activated by the hormone estrogen. Estrogen-receptor positive breast cancer is the most common type of breast cancer and accounts for about 70% of breast cancer tumors. Endocrine therapy, which inhibits estrogen receptor signaling, and Cyclin-dependent kinase 4 and 6 (Cdk4/6) inhibitors are the preferred first-line therapy for patients with estrogen receptor-positive cancers. We built a mathematical model of MCF7 cells (an estrogen receptor-positive breast cancer cell line) in response to these standard first-line therapies. This mathematical model can capture the experimentally observed protein and cell proliferation changes in response to various treatment conditions, including different drug combinations, different doses, and different treatment durations up to 28 days. The model can then be used to look for more effective treatment possibilities. In particular, our mathematical model predicted a strong synergism between Cdk4/6 inhibitors and endocrine therapy, which could allow significant reductions in drug dosage while producing the same effect. This synergism was verified by experiments. In addition to treatment methods where one drug or combination of several drugs is used continuously, we consider alternating among various therapies in a fixed cycle. The mathematical model can help us determine which drugs and which doses might be most appropriate. Since an alternating therapy doesn't inhibit one particular target non-stop, the hope is that alternating therapies can delay the onset of drug resistance, where the drug becomes less effective or stops working completely. Unfortunately, an initial 10- week experiment to test for differences in resistance to a mono-therapy versus an alternating therapy did not show a significant difference, pointing to the need for longer experiments to see if alternating therapies can actually make a difference in resistance. Mathematical models will be important for determining the drugs, doses, and time intervals to be used in these experiments, as figuring out the best options by trial and error in such long-term experiments is not practical.
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Šálková, Michaela. « Sledování obsahu 3-MCPD v ječmeni, sladu a pivu ». Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-376823.
Texte intégralRésumé :
The master’s thesis focuses on a process contaminant 3-MCPD (3-chloropropane-1,2-diol), which is formed during food processing. The first part of the thesis summarizes scientific knowledge about its chemical and physical properties, toxicity, occurrence in food and methods of analysis. In the second part is monitored the content of 3-MCPD in barley, in standard and special types of malts and beer. Samples were derivatized with phenylboronic acid (PBA) and 3-MCPD derivatives were analyzed by gas chromatography with a mass detector. Deuterated 3-MCPD was used as an internal standard. The limit of quantification was 1 gkg-1 for barley and malt samples and 10 gkg-1 in case of beer. The barley samples contained concentration of 3-MCPD below LOQ. In samples of malt was found concentration
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Ye, Qionghuan. « Strategies to Inhibit the Formation of 3-Monochloropropane Diol During Deep-Fat Frying ». Thesis, North Dakota State University, 2020. https://hdl.handle.net/10365/32048.
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3-monochloropropane-1,2-diol or 3-chloropropane-1,2-diol (3-MCPD) and glycidol are the most commonly occurring group of thermal process contaminants which are considered as “possible human carcinogen” and “probably carcinogenic to humans”, respectively. Potato strips prepared from three different potatoes cultivars (Russet Burbank, Ranger Russet, and Umatilla Russet) grown in North Dakota from the crop year 2018 were fried with vegetable oil at 190 ºC, respectively, for five consecutive days (8 h/day). The dynamic changes of 3-MCPD and glycidol equivalents were investigated during deep-fat frying. 3-MCPD equivalent in oil and potato strips decreased with increased frying time. Meanwhile, the content of glycidol equivalent increased with increased frying time. The major 3-MCPD and glycidol equivalents that were detected in the fried potato strips were those that migrated from the oils during frying. The application of absorbents, i.e., Magnesol and Celite, achieved the mitigation of 3-MCPD and glycidol in frying oil.
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Merkle, Sybille Barbara [Verfasser], et Bernward [Akademischer Betreuer] Bisping. « Analytik und technologische Minimierungsansätze von Monochlorpropandiol (MCPD), MCPD-Fettsäureestern und Glycidylestern in frittierten und geräucherten Fischerzeugnissen und Fischölen / Sybille Barbara Merkle ; Betreuer : Bernward Bisping ». Hamburg : Staats- und Universitätsbibliothek Hamburg, 2019. http://d-nb.info/1181328845/34.
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SANTOS, WALLAS HENRIQUE SOUSA DOS. « MCAD SHAPE GRAMMAR : PROCEDURAL MODELING FOR INDUSTRIAL MASSIVE CAD MODELS ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=34609@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Modelos CAD 3D são ferramentas utilizadas na indústria para planejamento e simulações antes da construção ou realização de tarefas. Em muitos casos, como por exemplo na indústria de óleo e gás, esses modelos podem ser massivos, ou seja, possuem informações detalhadas em larga escala no intuito de que sejam fontes de informações precisas. Para obtenção de navegação interativa nesses modelos é necessária uma combinação de hardware e software adequados. Mesmo hoje com GPUs mais modernas, a renderização direta desses modelos não é eficiente, sendo necessárias abordagens clássicas como descarte de objetos não visíveis e LOD antes de enviar os dados à GPU. Logo, para renderização em tempo real de modelos CAD massivos são necessários algoritmos e estruturas de dados escaláveis para processamento da cena de forma eficiente. O trabalho dessa tese propõe o MCAD (Massive Computer-Aided Design) Shape grammar, uma gramática expansiva que gera objetos para criar cenas 3D de modelos massivos de forma procedimental. Nos últimos anos, modelagem procedimental tem ganhado atenção para criar cenas 3D rapidamente utilizando uma representação compacta, que armazena regras de geração ao invés de representação explícita da cena. MCAD Shape grammar explora repetições e padrões presentes em modelos massivos para renderização de cenas, reduzindo o consumo de memória e processando a cena procedimentalmente de forma eficiente. Convertemos modelos reais de refinarias em MCAD Shape grammar e implementamos um renderizador para os mesmos. Os resultados mostraram que esta solução é escalável com alto desempenho, além de ser a primeira vez que modelagem procedimental é utilizada nesse domínio.
3D CAD models are tools used in the industry for planning and simulations before construction or completion of tasks. In many cases, such as in the oil and gas industry, these models can be massive, that is, they have large-scale detailed information in order to be sources of accurate information. Interactive navigation in these models requires a combination of appropriate hardware and software. Even nowadays with modern GPUs, the direct rendering of these models is not efficient, requiring classic approaches such as culling non-visible objects and LOD before sending the data to the GPU. Therefore, for real-time rendering of massive CAD models, we need scalable algorithms and data structures to efficiently process the scene. The work of this thesis proposes MCAD (Massive Computer-Aided Design) Shape grammar, an expansive grammar that procedurally generates objects to create 3D scenes of massive models. In recent years procedural modeling has drawn attention for quickly creating 3D scenes using a compact representation, which stores generation rules rather than explicit representation of the scene. MCAD Shape grammar explores repetitions and patterns present in massive models for rendering scenes, reducing memory footprint and procedurally processing the scene efficiently. We converted real refinery models into MCAD Shape grammar and implemented a renderer for them. Results showed that our solution is scalable with high performance, also it is the first time that procedural modeling is used in this domain.
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Valc, Lukáš. « Posouzení bezpečnosti činností obsluhy u vertikálního obráběcího centra MCFV 1260 ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417793.
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This diploma thesis deals with the safety assessment of operator’s activities at the MCFV 1260 vertical machining center. Then a system analysis of the issue is created with a proposal and justification of the chosen procedure. In the second part of the thesis there is solved the failure risk analysis, which is focused on the operations of the operator in the area of maintenance, service and during the operation of the vertical machining center located in the company TAJMAC – ZPS Zlín. The result of this thesis is the design and recommendation of preventive measures to reduce unacceptable risks in the relevant operations at the machining center.
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Enseroth, Timo [Verfasser]. « Konstruktion und Validierung der MCD-Skala zur Erfassung unterschwelliger organischer Psychosyndrome (Minimale Cerebrale Dysfunktion, MCD) im Erwachsenenalter / Timo Enseroth ». Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2011. http://d-nb.info/1026264200/34.
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Lecomte, Julie. « Effets des ligands de PPAR ? sur la voie de signalisation des oestrogènes dans les cellules cancéreuses mammaires ». Thesis, Nancy 1, 2009. http://www.theses.fr/2009NAN10009/document.
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Le récepteur alpha des œstrogènes (ERa) est une cible privilégiée dans le traitement du cancer du sein. En effet, 70% des tumeurs sont hormono-dépendantes, c’est-à-dire qu’elles expriment ERa et que les œstrogènes contrôlent leur prolifération. Par ailleurs, les agonistes du récepteur nucléaire « Peroxisome Proliferator Activated Receptor gamma » (PPAR?? inhibent la prolifération des cellules cancéreuses mammaires in vivo et in vitro. L’objectif de la thèse visait à déterminer si ces composés, en particulier ceux de la famille des thiazolidinediones, interféraient avec la voie de signalisation des œstrogènes. Les travaux ont porté sur 2 lignées cancéreuses mammaires hormono-dépendantes : MCF-7 et ZR-75-1. La troglitazone (TGZ), la ciglitazone et la 15déoxy-Prostaglandine J2 (15d-PGJ2) altèrent la signalisation œstrogénique en induisant la dégradation de l’ERa. ?Cette protéolyse fait appel au protéasome 26S et elle est plus accentuée pour la lignée ZR-75-1. Les composés qui altèrent la signalisation œstrogénique inhibent aussi fortement la prolifération cellulaire. La dégradation de ERa ne semble pas dépendre de l’activation des ligands de PPAR? puisqu’un agoniste puissant comme la rosiglitazone n’induit pas cet effet. L’utilisation d’antagonistes de PPAR?, de la ?2-TGZ, dérivé de la troglitazone qui n’active pas PPAR? ainsi qu’une approche par interférence ARN ont permis de démontrer que la protéolyse de l’ERa est bien liée à mécanisme indépendant de PPAR?. La littérature indiquait que la 15d-PGJ2 se liait de façon covalente à ERa, ?mais pas à l’isoforme ERß. Nous avons observé que la 15d-PGJ2 n’induisait pas la protéolyse de ERß. Une dégradation différentielle a aussi été observée avec les thiazolidinediones. En outre, l’activité transcriptionnelle de ERa est affectée précocement après l’exposition des cellules aux différents ligands, suggérant une modification du récepteur. Afin de savoir si une liaison covalente pouvait être à l’origine de la protéolyse, un groupement biotine a été greffé sur la ?2-TGZ afin de réaliser des expériences de pull-down. Ce composé n’a pas permis de démontrer l’hypothèse mais cette molécule induit plus efficacement que la molécule d’origine la protéolyse non seulement de l’ERa, ?mais aussi de la cycline D1. Des modifications des ligands de PPAR? ?pourraient donc avantageusement diminuer les doses efficaces. Ces mécanismes PPAR?-indépendants, qui aboutissent à la dégradation de la cycline D1 et de ERa mais pas de ERß pourraient être intéressants dans l’optique d’une application à la thérapeutique des cancers mammairesEstrogen receptor alpha (ERa) is a major target in breast cancer treatment. About 70% of breast cancers are estrogen-sensitive meaning that estrogens stimulate their growth. Ligands of PPAR? (Peroxisome Proliferator Activated Receptor gamma) inhibit breast cancer cell proliferation both in vivo and in vitro. The aim of this work was to determine whether PPAR? ligands could interfere with estrogen signalling pathway. The effects of Rosiglitazone (RGZ), Ciglitazone (CGZ), Troglitazone (TGZ) and the natural PPAR? agonist 15d-PGJ2 were investigated in two hormone-dependent breast cancer cell lines, MCF-7 and ZR-75-1. In both of them, TGZ, CGZ and 15d-PGJ2 induced an inhibition of ERa signalling associated with the proteasomal degradation of ERa. ZR-75-1 cells were more sensitive than MCF-7 to these compounds. Treatments that induced ERa degradation also inhibited cell proliferation after 24h. In contrast, 24h exposure to RGZ, the most potent activator of PPAR? disrupted neither ERa signalling nor cell proliferation. 9-cis retinoic acid never potentiated the proteasomal degradation of ERa. PPAR? antagonists did not block the proteolysis of ERa in MCF-7 and ZR-75-1 cells treated with TGZ. ERa proteolysis still occurred in case of PPAR? silencing as well as in case of treatment with the PPAR?-inactive compound ?2-TGZ, demonstrating a PPAR?-independent mechanism. A previous study indicated that 15d-PGJ2 was able to covalently modify ERa, ?but did not bind to ERß. First, we observed that in contrast to ERa, ERß proteolysis did not occur in MCF-7 cells exposed to 15d-PGJ2. A differential proteolysis was also observed in case of exposure to thiazolidinediones. Moreover, transfection experiments using pEREtkLuc showed that ERa functionality was affected early after exposure of MCF-7 cells to thiazolidinediones. In order to determine if a covalent binding of PPAR? ligands to ERa ?could lead to its proteolysis, a biotinylated derivative of ?2-TGZ was synthesized. However, pull-down assays performed using neutravidin beads did not allow to demonstrate a covalent interaction between ERa and biotinylated ?2-TGZ. When we verified the efficiency of biotinylated ?2-TGZ on ERa ?proteolysis induction, we observed that the substitution by biotine potentiated the TGZ-induced proteasomal degradation not only of ERa but also of cyclin D1. In conclusion, the design of new thiazolidinedione derivatives could lead to more efficient molecules able to affect differentially ER in a PPAR?-independent way and could be an interesting tool for breast cancer therapy
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Wang, Chao. « Oxydation catalytique des composés organiques volatils à l’aide de catalyseurs de type oxyde ». Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1332.
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Dans ce travail de recherche, des oxydes mixtes dopés par des métaux nobles ont été préparés et mis en œuvre dans la réaction d'oxydation catalytique du chlorure de vinyle (VC). Les catalyseurs d'oxyde composite de Co-Ce ont été préparés par des procédés sol-gel et testés pour l'activité d'oxydation du VC. L'analyse XPS a certifié que l'introduction de Ce favorisait la présence d'espèces de Co2 + et de Ce3 +, ce qui modifie l'environnement de coordination du réseau d'oxygène et génère plus de vacations d'oxygène. Les oxydes de cobalt modifiés par Ru ont été préparés et étudiés pour l'oxydation du VC. L'analyse XPS montre que le Ru4 + et le Co2 + modifie la concentration des espèces oxygènes sur la surface. Une proportion relative élevée de Co2+ et de Ru4+ perturbe également les lacunes en oxygène. Cela impacte l'activité catalytique et diminue la quantité de sous-produits chlorés. Des mousses cellulaires mésostructurées de phosphate de cobalt-SiO2 (CoPO-MCFs) ont été synthétisées avec succès par la méthode de croissance in situ. Les analyses XPS confirment une augmentation d'espèces d'oxygène de surface pour ce système catalytique. L'énergie apparente d'activation confirme cette tendance. L'influence de la morphologie des particules de Co3O4, sur l'activité catalytique du méthyl benzène et du chlorure de vinyle a été étudiée. Le Co3O4 cubique a montré une meilleure activité et une meilleure stabilité que celle de Co3O4 sphérique. La structure cubique, avec Co2 + exposée à la surface, est le site actif de l'oxydationIn this research works, composite oxides, noble metal supported oxides and noble supported MCFs were prepared, and their catalytic performances were investigated for the catalytic oxidation of vinyl chloride (VC). The Co-Ce composite oxide catalysts were prepared by citrate sol-gel methods, and tested for the activity of VC oxidation. The catalyst with high performance is the molar ratio of Co/Ce=7:3. The XPS analyse certified that the Ce introduction favored the presence of Co2+ and Ce3+ species, which changed the coordination environment of the oxygen lattice and generated more oxygen vacancies. At last, this catalyst exhibited a good performance and stability during 110 h of time on stream at 300 oC. Ru-modified cobalt oxides were prepared and studied for the VC oxidation. The XPS analyse certified that the Ru4+ will be in synergy with Co2+ concentration and this would also change the chemical coordination of oxygen on the surface. High relative proportion of Co2+ and Ru4+ will also devote to oxygen defects or vacancies. This would increased the catalytic activity and decrease the amount of chlorinated by-products.A novel heterostructured material, cobalt phosphate-SiO2 mesostructured cellular foams (CoPO-MCFs), was successfully synthesized by the in-situ growth method. The XPS confirmed a higher amount of surface oxygen species. The activation energy calculated from Arrhenius plots showed a lower value for VC oxidation. The influence of Co3O4 morphology, including cube and sphere, on catalytic activity of methylbenzene and vinyl chloride was studied. The Co3O4 cube had shown better activity and stability than that of the Co3O4 sphere. The cube structure, with Co2+ exposed on the surface, acted as the active site of the oxidation
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Salas, Oriana Ines Avila. « Fabricação de microambientes para crescimento celular utilizando polimerização via absorção de dois fótons ». Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-20122013-151051/.
Texte intégralRésumé :
Neste trabalho, demonstramos a fabricação de microambientes tridimensionais para investigar o crescimento celular. Inicialmente, desenvolvemos um sistema de microfabricação que utiliza fotopolimerização via absorção de dois fótons, com o qual se pode fabricar um conjunto de microestruturas com formas e espaçamentos pré-determinados. Este sistema de fabricação utiliza pulsos de femtossegundos, provenientes de um laser de Ti:safira operando em 790 nm. A intensidade destes pulsos é alta o bastante para induzir a absorção de dois fótons no fotoiniciador, o qual é responsável por promover a polimerização em uma resina acrílica. A natureza não linear da absorção de dois fótons confina a excitação ao volume focal, permitindo a fabricação de estruturas tridimensionais com alta resolução espacial. Para a obtenção dos microambientes, foi necessário o desenvolvimento de um sistema opto-mecânico de movimentação, tanto do feixe quando do substrato da amostra. Com esta técnica, fabricamos microambientes compostos de estruturas com diferentes formas (paralelepípedos, cilindros e cones) e espaçamentos, os quais foram caracterizados através de microscopia óptica e eletrônica. Para demonstrar a viabilidade destes microambientes para a investigação do crescimento celular, estes foram utilizados para monitorar o desenvolvimento da célula Michigan Cancer Foundation-7 (MCF-7), uma linhagem celular de adenocarcinoma de mama que apresenta fenótipo tumoral amplamente utilizada como modelo de estudo para câncer de mama. Observamos, via microscopia óptica de transmissão e fluorescência, o desenvolvimento das células MCF-7 nos distintos microambientes. Nossos resultados indicam uma melhor aderência e, portanto, desenvolvimento celular nas microestruturas cilíndricas. Observamos ainda uma maior densidade de células nos microambientes com estruturas separadas de 12 µm, a qual diminui com o aumento do espaçamento, de tal forma que para o microambiente com 30 µm, por exemplo, poucas células são observadas. Portanto, nossos resultados demonstram que os microambientes desenvolvidos são viáveis para estudos mais aprofundados em biologia celular, com potenciais aplicações em engenharia de tecido.In this work we have demonstrated the fabrication of tridimensional microenvironments for the investigation of cell growth. Initially we have developed a two-photon absorption photopolymerization microfabrication system, which allows producing a set of microstructures with predetermined forms and spacing. This fabrication system uses femtosecond pulses from a Ti: sapphire laser operating at 790 nm. These pulses are intense enough to induce two-photon absorption by the photoinitiator, that is responsible for promoting the polymerization in an acrylic resin. The nonlinear nature of the two-photon absorption confines the excitation to the focal volume, allowing the fabrication of tridimensional structures with high spatial resolution. In order to obtain the microenvironments, it was necessary to develop a movement system for both the laser beam and the sample substrate. With this technique we have fabricated microenvironments composed by structures with different geometries (parallelepipeds, cylinders and cones) and spacing, which were characterized by optical and scanning electron microscopes. To demonstrate the feasibility of the microenvironments for the investigation of cell growth, the samples were used to monitor de development of the Michigan Cancer Foundation-7 cell (MCF-7), a lineage of breast adenocarcinoma that has a tumoral phenotype and is highly used as a model in breast cancer studies. We have observed, through conventional optical and fluorescence microscopy, the growth of the MCF-7 cells in the various microenvironments. Our results indicate a better adhesion and, therefore, better development of cells on the cylindrical microstructures. We also observe a higher cell density in the microenvironments with microstructures having a spacing of 12 µm, which reduces as the distance between microstructures increases, in such a way that for the microenvironment with 30 µm spacing, for example, just a few cells are observed. Thus, our results demonstrate that the produced microenvironments are applicable in deeper studies in microbiology, with potential application in tissue engineering.
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Mendoza, Blanco Leonardo. « Revêtements protecteurs à base d'oxyde de cobalt, de titane ou de cérium pour la cathode de nickel des piles à combustible à carbonates fondus ». Paris 6, 2003. https://pastel.archives-ouvertes.fr/pastel-00001299.
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Sarvaiya, Hetal Abhijeet. « Mass Spectrometric Characterization of the MCF7 Cancer Cell Line : Proteome Profile and Cancer Biomarkers ». Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/42169.
Texte intégralRésumé :
The discovery of cancer biomarkers is crucial in the clinical setting to facilitate early diagnosis and treatment, thereby increasing survival rates. Proteomic technologies with mass spectrometry detection (MS) have the potential to affect the entire spectrum of cancer research by identifying these biomarkers. Simultaneously, microfabricated devices have evolved into ideal analysis platforms for minute amounts of sample, with promising applications for proteomic investigations and future biomarker screening. This thesis reports on the analysis of the proteomic constituents of the MCF7 breast cancer cell line using a shotgun 2-D strong cationic exchange/reversed phase liquid chromatography electrospray ionization tandem mass spectrometry (SCX/RP-LC-ESI-MS/MS) protocol. A series of optimization strategies were performed to improve the LC-MS experimental set-up, sample preparation, data acquisition and database searching parameters, and to enable the detection and confident identification of a large number of proteins. Over ~4,500 proteins were identified using conventional filtering parameters, and >2000 proteins using a combination of filters and p-value sorting. Of these, ~1,950 proteins had p<0.001 (~90%) and more than half were identified by ≥ 2 unique peptides. About 220 proteins were functionally involved in cancer related cellular processes, and over 100 proteins were previously described in the literature as potential cancer markers. Biomarkers such as PCNA, cathepsin D, E-cadherin, 14-3-3-sigma, antigen Ki-67, TP53RK, and calreticulin were identified. These data were generated by subjecting to mass spectrometric analysis ~42 µg of protein digest, analyzing 16 SCX peptide fractions, and interpreting ~55,000 MS2 spectra. Total MS time required for analysis was 40 h.
Selective SCX fractions were also analyzed by using a microfluidic LC platform. The performance of the microchip LC was comparable to that obtained with bench-top instrumentation when similar experimental conditions were used. The identification of 5 cancer biomarkers was enabled by using the microchip LC platform. Furthermore, this device was also capable to analyze phosphopeptides.Master of Science
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Tuna, Serkan. « Functional Characterization Of Microrna-125b Expression In Mcf7 Breast Cancer Cell Line ». Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612434/index.pdf.
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microRNA dependent gene expression regulation has roles in diverse processes such as differentiation, proliferation and apoptosis. Therefore, deregulated miRNA expression has functional importance for various diseases, including cancer. miR-125b is among the commonly downregulated miRNAs in breast cancer cells . Therefore we aimed to characterize the effects of miR-125b expression in MCF7 breast cancer cell line (BCCL) to better understand its roles in tumorigenesis. Here, we investigated mir-125 family members
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Warner, Christian. « Die pH-Wert-Regulation in kultivierten MCF-7-Mammakarzinomzellen ». [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967457246.
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Kotík, David. « Implementace jednoduchého web serveru do mikrokontroléru ColdFire MCF 52233 ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217778.
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The goal this semestral work is: Simple web server implementation into microcontroller ColdFire MCF 52233. We'll meet with microcontroller family ColdFire MFC 5223X, protocol HTTP 1.1 and Free ColdFire TCP/IP by Interniche. Like last part is suggestion of implementation web server into microcontroller.
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Bonadio, Raphael Severino. « Perfil de metilação global de DNA em células MCF-7 e MCF-10A após exposição transiente de nanopartículas de maghemita funcionalizadas com citrato ». reponame:Repositório Institucional da UnB, 2014. http://repositorio.unb.br/handle/10482/16874.
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Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Pós-Graduação em Nanociências e Nanobiotecnologia, 2014.Submitted by Ana Cristina Barbosa da Silva (annabds@hotmail.com) on 2014-11-13T17:36:35Z No. of bitstreams: 1 2014_RaphaelSeverinoBonadio.pdf: 1019534 bytes, checksum: 4151703aea9e28a2d016a232274697b0 (MD5)
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Introdução: Diversos estudos reportam alterações na expressão gênica em resposta àexposição de células à nanomateriais, mas até o presente momento não há nenhumestudo sobre a toxicidade a nível epigenético causada por nanoestruturas e seus efeitosem sucessivas gerações celulares. Portanto, torna-se necessário estudar esses fenômenosa fim de contribuir no desenvolvimento de nanopartículas mais adequadas paraaplicações biológicas. Objetivo: Avaliar o perfil de metilação global de DNA emcélulas MCF-7 e MCF-10A em cultivo após a cessão da exposição de nanopartículas demaghemita funcionalizadas com citrato. Materiais e métodos: As NPM-citrato foramsintetizadas pelo método de coprecipitação de Fe (II) e Fe (III) e adição direta de ácidocítrico. As caracterizações das NPM-citrato foram realizadas por microscopia (MET,HRTEM, MEV e AFM) e por diâmetro hidrodinâmico e potencial zeta. Para detectar asconcentrações sub-letais IC-10 e IC-20, foram realizados a exclusão de viabilidade porcontagem de células coradas com Azul Tripan e o ensaio de citotoxicidade peladetecção da Lactato Desidrogenase (LDH). O ensaio de proliferação celular foirealizado no sistema xCELLigence™ (Roche/ACEA). A detecção de ferro intracelularfoi realizada pelo ensaio do Azul da Prússia. O perfil de metilação global de DNA foirealizado por ensaio colorimétrico. A expressão das DNMTs foi realizada por qRTPCR.Resultados: As NPM-citrato causaram efeito citostático em células MCF-7 eMCF-10A quando administradas nas concentrações 30 e 60μgFe/mL durante 24h. Apósa cessão da exposição das NPM-citrato, verificou-se que a proliferação das célulasMCF-7 tratadas foi maior que das células não tratadas. Além disso, foi constatado queas NPM-citrato encontravam-se no interior das células durante todo o experimento e quehavia uma dinâmica de metilação de DNA, mesmo após a exposição transiente dasNPM-citrato. Também foram identificadas diferenças entre o acúmulo de transcritos deDNA metiltransferases. Discussão: Os nanomateriais possuem um risco intrínseco emaplicações biológicas, mesmo quando administrados em concentrações consideradasnão-tóxicas por meio de técnicas convencionais. Isso porque seus efeitos em sistemasbiológicos podem se estender a múltiplas gerações, mesmo durante exposiçãotransiente. Conclusão: As NPM-citrato promovem alterações significativas no perfil demetilação global de DNA em células MCF-7 e não promovem em MCF-10A e essefenômeno pode ser explorado para aplicações biomédicas futuras. _________________________________________________________________________________ ABSTRACT
Introduction: Several studies have reported changes in gene expression in response toexposure of cells to nanomaterials, but to date there is no study on the toxicity causedby nanostructures at epigenetic level and their effects in successive cell generations.Therefore, it becomes necessary to study these phenomena in order to contribute to thedevelopment of more appropriate nanoparticles for biological applications. Objective:To evaluate the profile of global DNA methylation in MCF-7 and MCF-10A cells inculture after cessation of exposure to maghemite nanoparticles functionalized with citricacid. Methods: The NPM-citrate were synthesized by coprecipitation of Fe (II) and Fe(III) method and direct addition of citric acid. The characterizations of NPM-citratewere performed by microscopy (TEM, HRTEM, SEM and AFM) and by analysis of thehydrodynamic diameter and zeta potential. To detect the sub-lethal concentrations IC-10and IC-20, we performed the counting of the cells stained with Trypan Blue andcytotoxicity assay for detection of lactate dehydrogenase (LDH). The cell proliferationassay was performed in xCELLigence ™ (Roche / ACEA) system. Detection ofintracellular iron assay was performed by Prussian Blue. The profile global DNAmethylation was performed by colorimetric assay. The expression of DNMTs wasperformed by qRT-PCR. Results: NPM-citrate caused cytostatic effect on MCF-7 andMCF-10A cells when given at concentrations of 30 and 60μgFe/ml for 24h. After thetransfer of the NPM-citrate exposure, it was found that the proliferation of MCF-7treated cells was higher than untreated cells. Furthermore, it was found that the NPMcitrateis found inside the cells throughout the experiment and had a dynamic DNAmethylation even after transient exposure of NPM-citrate. Differences between thetranscript accumulation of DNA methyltransferases were also identified. Discussion:The combination of nanotechnology and epigenetics is still poorly understood becausethese are frontier areas of knowledge. Thus, nanomaterials have an intrinsic risk inbiological applications, even when administered in non-toxic concentrations consideredby conventional techniques. This is because their effects on biological systems can beextended to multiple generations, even during transient exposure. Conclusion: TheNPM-citrate promote significant changes in global DNA methylation in MCF-7 cellsand do not promote in MCF-10A and this phenomenon can be exploited for futurebiomedical applications.
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Belluzzo, Marta. « Interferenti endocrini nelle acque potabili : presenza ed effetti su cellule MCF7 in coltura ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15061/.
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Il problema della presenza nell’acqua di sostanze in grado di interferire con il sistema endocrino (IE) è diventato negli ultimi anni motivo di crescente preoccupazione. Gli impianti di trattamento spesso non sono in grado di rimuovere gli IE dalle acque destinate al consumo umano, con possibili effetti negativi sulla salute.
Il presente lavoro di tesi si inserisce in questo contesto di crescente attenzione verso gli IE in un comparto ambientale importante come quello delle acque ad uso potabile. Nel 2017 sono state effettuate due campagne di campionamento, presso il potabilizzatore della Standiana di Ravenna, gestito da Romagna Acque-Società delle Fonti. L’acqua è stata campionata in ingresso e in uscita dall’impianto, oltre che in alcune fasi intermedie dentro al potabilizzatore, per verificare se ci siano passaggi che contribuiscono maggiormente alla rimozione degli IE. Sono state svolte sia analisi chimiche (LC-MS-MS), per rilevare la presenza di dieci sostanze rappresentative di differenti classi di IE, che biologiche (E-screen assay e test dei micronuclei), al fine di valutare l’eventuale presenza di sostanze ad azione estrogenica e/o genotossica.
Il potabilizzatore ha abbattuto in modo completo il 4-octilfenolo, in gran parte PFOS e BPA, mentre non è stato altrettanto efficace nel trattenere PFOA e nonilfenolo, che comunque risultano presenti nell’acqua in uscita a livelli inferiori rispetto ai limiti di legge. Il passaggio più efficace ad abbattere gli IE sembra essere quello con i filtri a carbone attivo. Le analisi biologiche hanno confermato la buona qualità dell'acqua erogata dal potabilizzatore, in quanto non hanno evidenziato effetti estrogeno-mimetici e/o tossici, né effetti genotossici.
In conclusione non sussistono situazioni di criticità relative alla presenza di IE nell’acqua erogata dal potabilizzatore della Standiana, sia per le ridotte concentrazioni riscontrate nell’acqua in entrata, sia per l’efficacia del processo di potabilizzazione.
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Rahlf, Elena [Verfasser]. « BRCA1 verändert die Strahlenempfindlichkeit durch Modifikation des Tumorstammzellanteils in MCF7 Zellen / Elena Rahlf ». Hamburg : Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky, 2020. http://d-nb.info/1228537798/34.
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Cooper, Leanne Claire. « The role of Hsp90 in the Wnt pathway of MCF7 breast cancer cells ». Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1004044.
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Breast cancer is one of the most common forms of cancer in not only South African women, but women all over the world. The molecular chaperone heat shock protein 90 (HSP90) is upregulated in cancer and is almost exclusively associated with proteins involved in intracellular signal transduction, thus it plays an important role in signalling pathways within the cell. In cancer, there is an aberrant activation of the Wnt signaling pathway, which results in stabilized β-catenin being able to translocate to the nucleus where it can trigger the transcription of oncogenes found to be involved in the self-renewal of cells. The level of β-catenin is usually kept in check by a destruction complex comprising glycogen synthase kinase 3-beta (GSK-3β), axin1, adenomatous polyposis coli (APC) which phosphorylate β-catenin, resulting in its ubiquitination and degradation. HSP90 has been found to be associated with GSK-3β, but whether this association is only transient is debatable. Very little is known about the association of HSP90 with other members of the Wnt pathway in breast cancer. In this study, we have attempted to further identify the direct associations between HSP90 and GSK-3β, β-catenin, p-β-catenin and axin1. Immunofluorescence and confocal microscopy co-localization studies suggested a potential association between HSP90 and these proteins. Treatment with HSP90 inhibitors, 17-AAG and novobiocin resulted in a shift of axin1 to what appeared to be the plasma membrane. The associations of HSP90 with GSK-3β, β-catenin, p-β-catenin and axin1 were confirmed biochemically by co-immunoprecipitation and inhibition using 17-AAG, geldanamycin and novobiocin. We showed, for the first time that HSP90 is associated in a possible complex with β-catenin, p-β-catenin and axin1 therefore is potentially involved in the modulation of p-β-catenin in the Wnt pathway through the stabilization of the destruction complex.
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Irvine, Alan David. « Mutation analysis in human keratin diseases ». Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268237.
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Nilsson, Henrik. « Vätgas och bränsleceller : Ny energi för Försvarsmakten ? » Thesis, Swedish National Defence College, Swedish National Defence College, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-106.
Texte intégralRésumé :
The purpose of this paper is to identify the current status of fuel cell technology and to establish whether said technology is mature enough to be implemented into the Swedish Armed Forces. The question to be answered in this paper is as follows: Can hydrogen gas and fuel cells be used as an alternative source of energy within the Swedish Armed Forces?
This paper is based on theoretical studies and reports from prior research done on fuel cells. By studying these facts a predictive answer has been obtained. The answer I have come to, is that the maturity of fuel cell technology is currently inadequate for the Swedish Armed Forces to implement, especially considering its harsh working conditions.
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Schulz, Bastian. « Entwicklung eines Reformierungssystems zur Bereitstellung von Synthesegas für den maritimen Betrieb einer MCFC-Brennstoffzelle ». Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2013. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-127774.
Texte intégralRésumé :
Die vorliegende Arbeit beschäftigt sich mit der Entwicklung eines dieselbetriebenen autothermen Reformierungssystems (ATR-Einheit) zur Bereitstellung von wasserstoff- und kohlenmonoxidreichem Synthesegas für den maritimen Betrieb einer MCFC-Brennstoffzelle. Aufgrund der niedrigen Schadstoffemissionen sowie des hohen Wirkungsgrades hat dieses System das Potential eine mögliche Alternative zu den bisherigen Schiffsdieselmotoren aufzuzeigen, welche die zukünftigen Emissionsgrenzwerte einhält und zudem noch zu Kosteneinsparungen durch einen geringeren Brennstoffverbrauch beiträgt.
Die Hauptkomponenten des Reformierungssystems umfassen im Wesentlichen einen autothermen Reformierungsreaktor sowie einen nachgeschalteten Entschwefelungsreaktor. Für den optimalen Betrieb der beiden Reaktoren wurde ein Verschaltungskonzept entwickelt und umgesetzt, welches durch zusätzliche Peripheriekomponenten wie Strömungsverteiler, Mischer und Wärmeübertrager ergänzt wurde. Diese haben die Aufgabe einen stabilen Reformierungs- und Entschwefelungsprozess zwischen 50 % bis 100 % Betriebslast zu gewährleisten, wofür diverse experimentelle und numerische Methoden zur Optimierung herangezogen wurden. Darüber hinaus wurde die Konzeptionierung der Gesamtverschaltung im Hinblick auf eine gute Regelbarkeit untersucht. Hierfür wurden mehrere Bypassschaltungen vorgesehen, welche bei Teillastbetrieb konstante Betriebstemperaturen am Eintritt des Entschwefelungsreaktors und der Brennstoffzellen ermöglichen.
Für die Bestimmung der optimalen Betriebskenngrößen wurden umfangreiche Prozesssimulationen durchgeführt mit Hilfe deren die Auslegung der einzelnen Baugruppen erfolgte. Darüber hinaus wurden insbesondere die optimalen O/C- und S/C-Verhältnisse bestimmt, welche sowohl einen hohen Wirkungsgrad als auch die Einhaltung der Systemrandbedingungen gewährleisten.
Mit Hilfe der ermittelten Betriebskenngrößen wurde ein Gesamtkonzept entwickelt, womit neben der konstruktiven Umsetzung insbesondere die Werkstoffauswahl für das druckbeaufschlagte System definiert werden konnte. Im Hinblick auf die Erzielung eines möglichst hohen Reformerwirkungsgrades unter stabilen Betriebsbedingungen wurde das Reformierungssystem als Kernkomponente eines Fuel Processing Moduls realisiert und charakterisiert. Hierbei konnte gezeigt werden, dass sich mit Hilfe des in dieser Arbeit entwickelten Systems ein stabiler Betrieb über mehrere Tage ohne Katalysatordeaktivierung realisieren lässt. Ebenfalls konnte ein modulierender Betrieb zwischen 50 % bis 100 % Betriebslast dargestellt werden, wobei alle Temperaturrestriktionen eingehalten wurden.
Zusammenfassend kann festgehalten werden, dass mittels des entwickelten Reformierungssystems eine mögliche Alternative zu den bisherigen Schiffsdieselmotoren aufgezeigt wurde, welche in Kombination mit MCFC-Brennstoffzellen die zukünftig geforderten Schadstoffrestriktionen erfüllt.
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Crabtree, Megan N. « Investigating Potential Bioactive Compounds from Rhodococcus and Their Effects on MCF7 Breast Cancer Cells ». Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etd/2278.
Texte intégralRésumé :
Many drugs used in the treatment of various cancers are derived from or influenced by compounds from nature. The soil bacterium Rhodococcus is of interest because of its identified secondary metabolic pathways and the production of novel natural antibiotics from several strains. In this study, a solid agar extraction method was used to collect compounds from strains of Rhodococcus. These bacterial compound extracts were then tested using a MTT assay in order to evaluate their effectiveness in augmenting MCF7 breast cancer cell death. The results of two way ANOVA analyses revealed 18 compound extracts from 15 strains of Rhodococcus that showed significant p-values when assayed with MCF7 breast cancer cells but nonsignificant interaction p-values when assayed with the healthy cell control. These results prompt further identification of specific compounds present in the bacterial extract that caused cell death as well as a mechanism of interaction with the breast cancer cells.
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Yano, Yuzo. « Digitalização de sinais de TV atraves de um sistema MCPD com predição e quantização ». [s.n.], 1986. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261037.
Texte intégralRésumé :
Orientador: Normonds AlensTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Campinas
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Resumo: Não informado.
Abstract: Not informed.
Doutorado
Doutor em Engenharia Elétrica
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Rosário, Hiago Fernando do. « Análise citotóxica do extrato bruto de tentáculos extraídos de três espécies de cnidários (Ceriantharia e Actiniaria) em duas linhagens celulares tumorais / ». Assis, 2020. http://hdl.handle.net/11449/192527.
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Orientador: Sérgio Nascimento StamparResumo: Acredita-se que o filo Cnidaria seja um dos mais antigos a se ter presença de toxina, devido a sinapomorfia do grupo: cnidoblastos. O composto de toxinas presente nos Cnidaria apresenta uma gama de efeitos nocivos aos humanos, porem demonstram um grande potencial para uso médico, principalmente pelas suas capacidades citoliticas. Neste trabalho analisamos a capacidade citotóxica do extrato bruto do tentáculo de três espécies de Cnidaria (Os ceriantos Ceriantheomorphe brasiliensis e Pachycerianthus multiplicatus e a anêmona de mar Actinia bermudensis) em células MCF-7 e HEP-2, através de ensaios de MTT e imagens, onde o extrato bruto de Ceriantheomorphe brasiliensis apresentou uma IC50 de 50 ug/ml para células MCF-7, e o de Actinia bermudensis com uma IC50 de 120 ug/ml a 60 ug/ml para células MCF-7 e de 120 ug/ml a 30 ug/ml para células HEP-2. Estes resultados corroboram com os estudos já realizados na área, onde a presença de citolisinas na peçonha de alguns cnidários atua em células cancerígenas provocando morte celular, despontando como potenciais candidatos de origem natural para a produção de agentes que atuam no combate ao câncer. Os extratos brutos de Ceriantheomorphe brasiliensis e Actinia bermudensis induziram morte celular nas linhagens celulares, mas são necessários mais estudos afim de aferir a extensão dessa capacidade e o real potencial de ambos os extratos.
Mestre
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Valgôde, Flávia Gomes Silva. « Avaliação do dano radioinduzido, capacidade de reparo e morte cecular em células humanas tumorais (T-47D e MCF-7) e não tumorais (MCF-10) de mama ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-16052012-141727/.
Texte intégralRésumé :
Câncer de mama é considerado uma das malignidades mais comuns que acometem as mulheres, representando cerca de uma em cada três de todas as neoplasias femininas. Aproximadamente, 90% dos casos de câncer de mama são esporádicos, atribuíveis aos eventos somáticos e cerca de 10% estão associados com a história familial e destes somente 4-5% são decorrentes de fatores hereditários. Em clínica, a radiação ionizante é a principal ferramenta utilizada no controle do crescimento tumoral, além da intervenção cirúrgica e quimioterapia. Há, no entanto, poucas infomnações no que diz respeito a resposta celular frente à ação da radiação ionizante em células-alvo, isto é, em linhagens celulares originárias de câncer de mama. O presente estudo foi proposto para analisar a radiossensibilidade de células humanas tumorals (T-47D e MCF-7) e não tumorals (MCF-10), originárias de mama, submetidas a várias doses (0,5 a 30 Gy) de radiação y de 60Co (0,72 - 1,50 Gy/min). Para tanto, foram utilizados como parâmetros de radiossensibilidade, dano radioinduzido ao DNA, capacidade de reparo e morte celular, por meio das técnicas do micronúcleo, eletroforese de microgel (teste do cometa) e viabilidade celular. Os dados obtidos mostraram que as linhagens tumorais (T-47D e MCF-7) foram mais radiossensíveis que a linhagem não tumoral (MCF-10) para todos os testes utilizados. A linhagem T-47D foi a que apresentou uma maior quantidade de dano radioinduzido, um ciclo celular mais acelerado e uma maior taxa de morte celular. As três linhagens celulares apresentaram uma capacidade de reparo relativamente eficiente, tendo em vista que uma hora após a irradiação, todas elas exibiram uma redução considerável de dano radioinduzido quando comparadas logo após as exposições. Os testes empregados mostraram ser seguros, sensíveis e reprodutíveis e permitiram quantificar e avaliar danos induzidos ao DNA, capacidade de reparo e morte celular, nas três linhagens originárias de mama humana.Breast cancer is one of the most common malignancies that account women, representing about one in three of all female neoplasm. Approximately, 90% of cases are considered sporadic, attributed to somatic events and about 10% have a family history and this only 4 - 5 % is decurrent of hereditary factors. In the clinic, ionizing radiation is a major tool utilized in the control of tumour growth, besides surgery and chemotherapy. There is, however, little information concerning cellular response to the action of ionizing radiation in the target cells, i.e., cell lines originating from breast cancer. The present study proposed to analyze the radiosensitivity of the human tumorigenic (T-47D and MCF-7) and nontumorigenic (MCF-10) cell lines, originating from breast and submitted to various doses (0.5 to 30 Gy) of 60Co rays (0.72 - 1.50 Gy/min). For this purpose, DNA radioinduced damage, repair capacity and cell death were utilized as parameters of radiosensitivity by micronucleus, single cell gel electrophoresis (Comet assay) and cell viability techniques. The data obtained showed that tumorigenic cell lines were more radiosensitive than nontumorigenic breast cells in all assays here utilized. The T-47D cell line was presenting the highest amount of radioinduced damage, a more accelerated proliferation rate and a higher rate of cell death. The three cell lines presented a relatively efficient repair capacity, since one hour after the irradiation all of them showed a considerable reduction of radioinduced damage. The techniques employed showed to be secure, sensitive and reproducible, allowing to quantify and evaluate DNA damage, repair capacity and cell death in the three human breast cell lines.
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VALGODE, FLAVIA G. S. « Avaliação do dano radioinduzido, capacidade de reparo e morte celular em células humanas tumorais (T-47D e MCF-7) e nao tumorais (MCF-10) de mama ». reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11710.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Arvidsson, Ann-Christine. « Framtagningav miljöbedömningsmetod av leverantörer : arbetet utfört hos Parker Hannifin AB MCD ». Thesis, University West, Department of Informatics and Mathematics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-889.
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Sin, Yuan Yan (Angie). « How mitochondrial DNA mutations affect the growth of MCF-7 clones ». Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1392.
Texte intégralRésumé :
Mitochondria are the main sites for adenosine triphosphate (ATP) generation within most cells. Structural and functional alterations of mitochondria due to genetic abnormalities of mitochondria can cause respiratory chain dysfunction. In this study, the important role of mitochondria in energy metabolism was determined by comparing the effect of mitochondrial DNA (mtDNA) mutations on growth patterns and oxidative phosphorylation (OXPHOS) enzyme activities of six isolated clones (B5, B12, D4, D9, E1 and E8); as well as the effect of ATP supplement to culture using the slowest growing clone. The isolated clones had shown distinct growth pattern and morphology. The difference in proliferation rates among the clones was ascertained by the doubling times (B5=26.4h. B12=43.2h. D4=25.7h. D9=33.6h. E1=26.9h and E8=28.8h). The clone's slow growth rate was likely the result of mitochondrial mutations in the 16S rRNA gene, ND1, ND4, ND6 and COX III. Five heteroplasmic mutations were found in clone B12 (G2480T, C2513G, A2520T, C9527T and C14263G), one heteroplasmic mutation in clone D9 (A4137G) and one homoplasmic mutation in clone D4 (C11496). The mutations in clone B12 appeared to be deleterious to the cell by disrupting mitochondrial OXPHOS activities and reducing energy output. Additionally, extracellular ATP supplement to OXPHOS deficient clone B12 facilitated cell growth and enhances the gene expression. Increased expression of mtDNA-encoded respiratory chain complexes observed in clone B12 compared to clone D4 may reflect mitochondrial genomic adaptation to perturbations in cellular energy requirements. The stimulation of mitochondrial biogenesis may be a cellular response in compensation for defects in OXPHOS associated with mtDNA mutations. My data support the hypothesis that the variability in functional manifestations of mtDNA is attributed to the nature of the mutation, number of mutation and the gene specifically affected. These results will help to further our understanding of the relationship between mitochondrial mutation and cellular function.
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Richard, Christina. « Mechanism of inhibition of MCF-7 cell proliferation by alkyllysophospholipids (ALPs) ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0002/MQ41763.pdf.
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Singer, R. « Matrix induced effects in the MCD spectra of isolated metal atoms ». Thesis, University of East Anglia, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374272.
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Wolff, Pamela A. Carleton University Dissertation Chemistry. « Electronic and magnetic hypersensitivity in the MCD spectra of lanthanide complexes ». Ottawa, 1990.
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43
Khurshid, Asma. « The effect of the polyadenylation inhibitor Cordycepin on MCF-7 cells ». Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28835/.
Texte intégralRésumé :
Cordycepin (3′-deoxyadenosine) is a medicinal bioactive component of the caterpillar fungi (Cordyceps and Ophicordyceps). It is reported to have nephroprotective, antiapoptotic, anti-metastatic, hepatoprotective (Yue et al. 2013), inflammatory effects, antioxidant, anti-tumor, immunomodulatory and vasorelaxation activities. Cordycepin is well known to terminate and inhibit polyadenylation, both in vitro and in vivo. Other proposed mechanisms of action of cordycepin include activation of adenosine receptors, activation of AMP dependent kinase (AMPK) and inhibition of PARP1. The purpose of this study is to elucidate the biological and pharmacological effects of cordycepin on cancer cell lines such as MCF-7 cells. In this study I found that cordycepin reduces the cell proliferation in all examined cell lines without always exerting an effect on 4EBP phosphorylation and protein synthesis rates. Therefore, the effects on protein synthesis via inhibition of mTOR, which were previously reported, are not only the sole reason for the effect of cordycepin on cell proliferation. Knockdown of poly (A) polymerases reduces cell proliferation and survival, indicating that poly (A) polymerases are potential targets of cordycepin. I studied different adenosine analogues and found that 8 aminoadenosine, the only one that also consistently inhibits polyadenylation, also reduces levels of P-4EBP. It also inhibits the expression of specific genes indicating that the effects on polyadenylation, mTOR signalling and gene expression are linked. Also consistent with polyadenylation inhibition as the major mode of action is the fact that the effects of cordycepin on gene expression are predominantly post-transcriptional. However, knockdown of poly (A) polymerases did not have the same effects on gene expression or on polyadenylation, indicating that cordycepin may act as a dominant negative rather than as a null mutant. This is consistent with the fact that cordycepin is known to arrest a normally transient polyadenylation complex. We performed microarray analysis of cordycepin treated MCF-7 cells and found that the downregulated mRNAs were predominantly involved in transcriptional regulation, cell proliferation, cell cycle and cell migration. These data show that cordycepin is a promising new drug for cancer and indicates that the mode of action it is likely to be through the inhibition of polyadenylation.
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Miranda, Juliana Xavier de. « Efeitos do tratamento com selênio no crescimento e marcas epigenéticas de células de adenocarcinoma mamário humano MCF-7 ». Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/9/9132/tde-11032013-090654/.
Texte intégralRésumé :
O câncer de mama representa problema mundial de saúde pública e a causa mais frequente de morte por câncer entre as mulheres. A identificação de agentes moduladores de marcas epigenéticas, tais como metilação global do DNA e modificações pós-tradução em histonas, compreende alternativa promissora para estabelecimento de estratégias de controle da carcinogênese mamária. Dentre os nutrientes, o elemento traço essencial selênio (Se) pode ser destacado como agente dietético com potencial anti-câncer de mama e que poderia atuar modulando processos epigenéticos. Entretanto seus mecanismos de ação são pouco elucidados. Este estudo objetivou, assim, identificar efeitos do tratamento com selênio no crescimento e marcas epigenéticas de células de adenocarcinoma mamário humano MCF-7. Células MCF-7, positivas para o receptor de estrógeno, foram tratadas com ácido metilselenínico (MSA) ou selenito de sódio (ST) por diferentes tempos e em diferentes concentrações. Foram avaliados: padrão de proliferação (ensaio cristal violeta) e viabilidade celular (método de exclusão azul de tripan); integridade de membrana plasmática (citometria de fluxo); níveis de fragmentação do DNA (citometria de fluxo), distribuição das fases do ciclo celular (citometria de fluxo); apoptose (citometria de fluxo/ marcação dupla com Anexina V - Iodeto de propídio); níveis de lisina 9 acetilada (H3K9ac) e trimetilada (H3K9me3) em histona H3; níveis de lisina 16 acetilada (H4K16ac) em histona H4 (Western blot); padrão de metilação global do DNA (HPLC-DAD); expressão de gene supressor de tumor (RASSF1a; qPCR) e padrão de metilação da região promotora (RASSF1a e RARβ; MS-PCR); expressão da enzima DNA metilstransferase 1 (DNMT1) (Western Blotting). Comparado ao grupo controle de células não tratadas (GC), ambos os tratamentos com MSA ou ST inibiram a proliferação e viabilidade de células MCF-7 de forma dose e tempo dependente. Ambas as formas químicas de Se induziram a parada do ciclo celular, aumentando (p< 0,05) a proporção de células na fase G2/M e reduzindo (p< 0,05) a proporção daquelas nas fases G0/G1 e S. Os tratamentos com MSA favoreceram a morte celular por apoptose, que foi associada com nível de fragmentação de DNA aumentado (p< 0,05), e reduzida ruptura da membrana plasmática associada com a exposição aumentada (p< 0,05) de fostadilserina. Por outro lado, o ST aumentou (p< 0,05) a fragmentação do DNA e (p< 0,05) a positividade ao iodeto de propídio associado à indução de necrose (p< 0,05). Dentre os mecanismos epigenéticos investigados, 1,6µM e 2µM reduziram a acetilação de H3K9ac (72h; p< 0,05) e aumentaram a de H4K16ac (96h; p< 0,05). O tratamento por 96h com 2µM de MSA reduziu (p< 0,05) a metilação de H3K9me3. Ambos MSA e ST não alteraram o padrão de metilação global do DNA, mas reduziram a expressão de DNMT1, após 96h com 2µM de MSA (p< 0,001; 88%) e após 120h com 10µM de ST (p< 0,001; 96%). ST, mas não o MSA, aumentou (p< 0,05; 45%) a expressão do gene RASSF1a. Em ambos os grupos tratados com MSA ou ST, bem como no GC, a região promotora dos genes RASSF1a e RAR estavam predominantemente metiladas. Estes resultados fornecem evidências de que as ações anti-câncer de mama de compostos do selênio dependem de sua forma química. Além disso, a modulação de processos epigenéticos parecem ser relevantes para as ações inibitórias do MSA em células de câncer de mama.Breast cancer is a global public health problem and the most frequent cause of cancer death among women. The identification of agents able to modulate epigenetic marks, such as global DNA methylation and histone post-translational modifications, comprises promising alternative for establishing control strategies on mammary carcinogenesis. Among the nutrients, the essential trace element selenium (Se) can be highlighted as a dietary agent with potential anti-breast cancer and could act by modulating epigenetic processes. However its mechanisms of action are poorly understood. This study aimed, therefore, to identify the effects of selenium treatment on growth and epigenetic marks of MCF-7 human breast adenocarcinoma cells. MCF-7 cells, positive for estrogen receptor, were treated with methylseleninic acid (MSA) or sodium selenite (ST) for different times and in different concentrations. Evaluated parameters included: cell proliferation (crystal violet assay) and cell viability (trypan blue exclusion assay); plasma membrane integrity (flow cytometry); levels of DNA fragmentation (flow cytometry), apoptosis (flow cytometry - double labeling with Annexin V - propidium iodide); distribution of cell cycle phases (flow cytometry); acetylated (H3K9ac) and trimethylated (H3K9me3) lysine 9 levels on histone H3; acetylated (H4K16ac) lysine 16 level on histone H4 (Western blot); global DNA methylation (HPLC-DAD); tumor suppressor gene expression (RASSF1a; qPCR) and promoter methylation (RASSF1a, RARβ; MS-PCR); DNA methyltransferase 1 (DNMT1) expression (Western blot). Compared to untreated cells (controls), both MSA and ST inhibited (p< 0.05) MCF-7 cell proliferation and viability in a dose- and time-dependent manner. Treatments with MSA favored cell death by apoptosis, that was associated with increased (p< 0.05) DNA fragmentation level, reduced plasma membrane rupture associated with high (p< 0.05) phosphatidylserine exposure. On the other hand, ST increased (p< 0.05) DNA fragmentation, enhanced (p< 0.05) propidium iodide positivity associated to necrosis induction (p< 0,05). Both chemical forms of Se induced nduced cell cycle arrest, increasing (p< 0.05) the proportion of cells in G2/M phase and reducing (p< 0.05) the proportion of those in G0/G1 and S phases. Among the epigenetic mechanisms investigated, 1.6µM and 2µM of MSA reduced acetylation of H3K9ac (72h, p< 0.05) and increased the H4K16ac (96h, p< 0.05). The treatment for 96h with 2µM of MSA reduced (p< 0.05) the H3K9me3 methylation. Neither MSA nor ST altered (p> 0.05) global DNA methylation, while both compounds reduced (p< 0.05) DNMT1 protein expression, after 96h with 2µM of MSA (p< 0.001; 88%) and after 120h with 10µm of ST (p< 0.001; 94%). ST, but not MSA, increased (p< 0.05; 45%) RASSF1a gene expression. In control and Se-treated cells promoter regions of RASSF1a and RARβ were predominantly methylated. These results provide evidence that the anti-breast cancer actions of selenium compounds depend on its chemical form. Additionally, modulation of epigenetic processes seems to represent a relevant feature of MSA inhibitory effects in breast cancer cells.
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Danesfahani, Gholam Reza. « A study in optimising a multicarrier demultiplexer demodulator (MCDD) for on-board processing (OBP) satellites ». Thesis, University of Surrey, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309262.
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Alokail, Majed Saleh Abdullah. « Parathyroid hormone-related peptide and parathyroid hormone-related peptide receptor in breast cancer MCF7 cells ». Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297420.
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Flanigan, Matt. « Modulation of the sodium/iodide symporter (NIS) by MEK inhibition in MCF7 breast cancer cells ». Connect to resource, 2009. http://hdl.handle.net/1811/36943.
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Sobantu, Mandisa Pamela. « The antioxidative and cytotoxic effects of hibiscus sabdariffa on mcf7 and mcf12a breast cell lines ». Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2235.
Texte intégralRésumé :
Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2015.Cancer is the leading cause of death in both developed and developing countries. In particular, breast cancer is regarded as the most common neoplastic disease in females and accounts for the high mortality rates in women. Increased mortality rates could be attributed to ineffective current cancer treatment modalities that have been implicated to cause multidrug resistance, high toxicity and induction of several side effects. In addition, oxidative stress appears to play a role in the development of breast cancer. Therefore, current cancer research aims to search for plant based anticancer compounds with less side effects and toxicity towards the human body. An example of such a plant is Hibiscus sabdariffa also known as roselle and is reported to have bioactive compounds that exhibit anticancer and antioxidant effects. However, the effects of Hibiscus sabdariffa on breast cancer in relation to oxidative stress and apoptosis have not been investigated. In this research study, the aim was to evaluate the cytotoxic and antioxidant effects of water and methanolic extracts of Hibiscus sabdariffa (HS) on cancerous MCF7 and non-cancerous MCF12A breast cell lines with special reference to oxidative stress and apoptosis. This was done based on the fact that HS has been documented for its traditional use against cancer and other ailments.
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Wijayasinghe, Athula. « Development and Characterisation of Cathode Materials for the Molten Carbonate Fuel Cell ». Doctoral thesis, KTH, Materials Science and Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3811.
Texte intégralRésumé :
Among the obstacles for the commercialization of the MoltenCarbonate Fuel Cell (MCFC), the dissolution of thestate-of-the-art lithiated NiO cathode is considered as aprimary lifetime limiting constraint. Development ofalternative cathode materials is considered as a main strategyfor solving the cathode dissolution problem. LiFeO2and LiCoO2had earlier been reported as the most promisingalternative materials; however, they could not satisfactorilysubstitute the lithiated NiO. On the other hand, ternarycompositions of LiFeO2, LiCoO2and NiO are expected to combine some desirableproperties of each component. The aim of this work was todevelop alternative cathode materials for MCFC in the LiFeO2-LiCoO2-NiO ternary system. It was carried out byinvestigating electronic conductivity of the materials, firstin the form of bulk pellets and then in ex-situ sinteredporous-gas-diffusion cathodes, and evaluating theirelectrochemical performance by short-time laboratory-scale celloperations.
Materials in the LiFeO2-NiO binary system and five ternary sub-systems,each with a constant molar ratio of LiFeO2:NiO while varying LiCoO2content, were studied. Powders withcharacteristics appropriate for MCFC cathode fabrication couldbe obtained by the Pechini method. The particle size of LiFeO2-LiCoO2-NiO powders considerably depends on thecalcination temperature and the material composition. Theelectrical conductivity study reveals the ability of preparingLiFeO2-LiCoO2-NiO materials with adequate electricalconductivity for MCFC cathode application.
A bimodal pore structure, appropriate for the MCFC cathode,could be achieved in sintered cathodes prepared usingporeformers and sub-micron size powder. Further, this studyindicates the nature of the compromise to be made between theelectrical conductivity, phase purity, pore structure andporosity in optimization of cathodes for MCFC application. Cellperformance comparable to that expected for the cathode in acommercial MCFC could be achieved with cathodes prepared from20 mole% LiFeO2- 20 mole% LiCoO2- 60 mole% NiO ternary composition. It shows aniR-corrected polarization of 62 mV and a iR-drop of 46 mV at acurrent density of 160 mAcm-2at 650 °C. Altogether, this study revealsthe possibility of preparing LiFeO2-LiCoO2-NiO cathode materials suitable for MCFCapplication.
Keywords: molten carbonate fuel cell (MCFC), MCFC cathode,LiFeO2-LiCoO2-NiO ternary compositions, electrical conductivity,porous gas diffusion electrodes, polarization, electrochemicalperformance, post-cell characterization.
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Moretto, Patricia. « Thromboprophylaxis in Hospitalized Medically Ill Cancer Patients ». Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30656.
Texte intégralRésumé :
Introduction: Thromboprophylaxis recommendations for hospitalized cancer are based on trials done for the general medically patients, as there are no randomized clinical trials(RCTs) looking at thromboprophylaxis in medically ill patients with cancer. Methods: To determine if thromboprophylaxis is safe and effective to prevent VTE these patients, a Systematic Review(SR) was done. A survey was performed to assess: clinical equipoise, trial design and minimally clinically important difference(MCID) for a potential trial. Lastly, a pilot study for an RCT was designed. Results: The pooled RR of VTE was 0.91 (95%CI:0.21 to 4.0;I2:68%) among hospitalized cancer patients receiving thromboprophylaxis compared to placebo. 63.9% believe there is clinical equipoise and 58.3% would consider participating in a RCT comparing different agents/dosing. The MCID for absolute reduction in symptomatic VTE between two arms was 2% and for “acceptable” increase in major bleeding events was 1%. Conclusion: The risk-benefit ratio of current doses of thromboprophylaxis administered to hospitalized cancer patients is unclear and additional RCTs are necessary.