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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Locally Administered Particle-Anchored Cytokines Safely Enhance Cancer Immunotherapy

Niu, Liqian 16 May 2024 (has links)
Cancer immunotherapy has long been proposed as a powerful approach to curing tumors, based on the natural function of the immune system in protecting its host with specificity, thus holding the potential for developing long-term memory that prevents tumor recurrence. However, the immunosuppressive feature of the tumor microenvironment prevents the patients' own immune system from functioning normally in the fight against cancer. As one of the most potent cancer immunotherapies, immunostimulatory cytokines have been shown to elicit anti-tumor immune responses in preclinical studies, but their clinical application is limited by severe immune-related adverse events upon systemic administration. None of the current delivery strategies can fully address issues of toxicities and sustainably supply cytokines over the course of a few days without compromising cytokines' structural integrity. Herein, we have developed a novel formulation to anchor potent cytokine molecules to the surface of large-sized particles (1 µm) for local cancer treatment. The cytokines are confined in tumors and have minimal systemic exposure over a few days following intratumoral injection, thereby eliciting anti-tumor immunity while avoiding the systemic toxicities caused by the circulating cytokines. Such particle-anchored cytokines can be synergistic with other immunotherapies, including immune checkpoint blockade antibodies and tumor antigens, to safely promote tumor regressions in various syngeneic tumor models and genetically engineered murine tumor models. / Doctor of Philosophy / Cancer immunotherapy is a promising method to treat cancer by harnessing the power of the body's immune system, which naturally fights off diseases and can remember and prevent diseases from returning. Unfortunately, cancers create a hostile environment that weakens the immune system's ability to combat the disease effectively. Among the treatments explored, immunostimulatory cytokines (unique proteins that boost the immune system) have shown great promise in laboratory studies for their ability to fight cancer. However, when these proteins are administered to patients, they can cause severe side effects due to their systemic dissemination throughout the body. Herein, by attaching the potent cytokines to large-sized particles (1 µm), and injecting them directly into the tumor, their cancer-fighting abilities are focused precisely where they are most needed. This targeted delivery minimizes the cytokines' presence in the rest of the body, dramatically reducing the risk of side effects associated with their systemic dissemination. This method not only shows promise on its own but also enhances the effectiveness of other cancer treatments. Our findings suggest a new, safer way to encourage the body's defense system to fight cancer more effectively.
122

Naturanaloge Optimierungsverfahren zur Auslegung von Faserverbundstrukturen / Natural analog optimization methods for the design of fiber composite structures

Ulke-Winter, Lars 18 April 2017 (has links) (PDF)
Die vollständige Ausnutzung des Leichtbaupotentials bei der Dimensionierung von mehrschichtigen endlosfaserverstärkten Strukturbauteilen erfordert die Bereitstellung von geeigneten Optimierungswerkzeugen, da bei der Auslegung eine große Anzahl von Entwurfsvariablen zu berücksichtigen sind. In dieser Arbeit werden Optimierungsalgorithmen und -strategien zur Lösung wissenschaftlicher Fragestellungen für industrielle Anwendungen bei der Konstruktion von entsprechenden Faserkunststoffverbunden entwickelt und bewertet. Um das breite Anwendungsspektrum aufzuzeigen, werden drei unterschiedliche repräsentative Problemstellungen bearbeitet. Dabei wird für Mehrschichtverbunde die Festigkeitsoptimierung hinsichtlich eines bruchtypbezogenen Versagenskriteriums vorgenommen, ein Dämpfungsmodell zur Materialcharakterisierung entworfen sowie eine bivalente Optimierungsstrategie zur Auslegung von gewickelten Hochdruckbehältern erstellt. Die Grundlage der entwickelten Methoden bilden dabei jeweils stochastische naturanaloge Optimierungsheuristiken, da die betrachteten Aufgabenstellungen nicht konvex sind und derartige Verfahren flexibel eingesetzt werden können. / The full utilization of the light weight potential in the dimensioning of multilayer fiber reinforced composites requires suitable optimization tools, since a large number of design variables has to be taken into account. In this work, optimization algorithms and strategies for the solution of scientific questions for industrial applications are developed and evaluated in the design of corresponding fiber-plastic composites. In order to show the wide range of applications, three different representative topics have been chosen. It will carry out a strength optimization for multilayer composites with regard to a type-related failure criterion, devolop a damping model for material characterization and established a bivalent optimization strategy for the design of wound high-pressure vessels. The developed methods are based on stochastic natural-analog optimization heuristics, since the considered tasks are not convex and such methods can be used in a very flexible manner.
123

Características funcionais e potencial terapêutico dos receptores Fc na inflamação sistêmica / Functional characteristics and therapeutic potential of Fc receptors in systemic inflammation

Correia, Mario Diego Teles 29 April 2019 (has links)
Introdução: Os receptores Fc são proteínas de importância crucial no processo saúde-doença. São responsáveis pela ativação de mecanismos efetores e modulam a resposta imune e inflamatória. Têm papel central na patogênese de doenças autoimunes, sepse e doenças neoplásicas. O lúpus, protótipo das doenças autoimunes e a sepse, infecção grave que causa disfunção orgânica, são doenças inflamatórias nas quais o papel dos receptores Fc vêm sendo desvendados. Essas patologias têm alta morbidade e mortalidade, impondo enormes custos para sociedade. A descoberta que a E. coli se liga ao receptor CD16 (FcGamaRIII) para evadir-se do sistema imune, através da ligação com a proteína wzxe presente em sua membrana, torna esse receptor um alvo terapêutico interessante. O CD16 é um FcGamaR com ITAM que classicamente tem função ativadora e gera respostas inflamatórias ao se ligar a imunocomplexos. Porém, na sepse, a ligação direta com a E. coli induz uma ativação ITAMi, que bloqueia a produção de ROS e inibe a fagocitose e a morte desta bactéria. A manipulação dessa ativação inibitória (ITAMi), aparentemente anti-inflamatória, pode ser uma estratégia efetiva para o tratamento de doenças inflamatórias como a sepse e o lúpus. Inicialmente visamos avaliar a importância fisiológica e o papel terapêutico do peptídeo ligante do CD16, em modelo de sepse e em modelo de lúpus induzido por pristane, respectivamente. De maneira similar ao CD16, o CD89 (FcAlfaRI) é capaz de mediar uma sinalização dual, ativatória ou inibitória, que depende da forma como se dá sua ligação às imunoglobulinas e imunocomplexos. Por isso, num segundo momento, averiguamos se o FcAlfaRI (CD89) poderia se ligar à bactérias de maneira direta, na ausência de ligantes cognatos e mediar respostas pro ou anti-inflamatórias, protegendo ou não o hospedeiro. Metodologia: Camundongos C57Bl/6, WT e CD16KO com lúpus induzido por pristane, foram tratados com o peptídeo CYWGGTEGAC(IRG Bioscience,USA). A expressão gênica e protéica de diversas citocinas, assim como genes associados a assinaturas de interferon foram avaliados nos pulmões desses animais. Utilizamos também um modelo de sepse através da injeção intra-peritoneal de E. coli WT e E. coli mutante wzxe -/-, no qual avaliamos mortalidade e produção de citocinas. Realizamos experimentos in vitro com BMM e BMDC murinos, fagócitos humanos e bactérias. A expressão de CD89 e de receptores cognatos foi avaliada através de citometria de fluxo. Empregamos a citometria de fluxo com imagem para análise da fagocitose. Foram realizados também, experimentos in vivo com camundongos WT e transgênicos: CD89tg, CD89R209Ltg CD89tgCD16KO, CD16KO e PCRKO. Comparamos mortalidade, produção de citocinas, quantidade de bactérias e lesão tecidual em modelos de CLP e de pneumonia por administração nasal de S. pneumoniae. Produção de ROS pelos BMM foi avaliada por microscopia confocal e, nos PMN, por quimioluminescência. Imunoprecipitação e immunoblotting foram utilizados para avaliar recrutamento de syk e SHP-1. Utilizamos ELISA para ensaios de ligação de bactérias com CD89 e para quantificar TNF-Alfa, IL-1 e IL-6. Resultados: Camundongos injetados com a bactéria mutante wzxe-/- sobreviveram mais e produziram quantidade menor de citocinas reforçando o papel chave da proteína wzxe, no mecanismo de evasão imune da E. coli. Camundongos WT e CD16KO com lupus induzido por pristane, tratados ou não com peptídeo CYWGGTEGAC, não apresentaram diferenças na expressão gênica nem protéica de citocinas nem em genes associados a assinaturas de interferon em seus pulmões. O CD89 interage diretamente com bactérias gram-positivas e gram-negativas. A interação bactéria-CD89 em macrófagos murinos induz ativação celular, fagocitose e morte bacteriana, que são dependentes da cadeia FcRGama. Essa mesma interação protege contra a mortalidade em dois modelos de sepse (CLP e pneumonia) e é dependente da cadeia FcRGama e indepedente de PCR e IgA anti-bactéria. Conclusões: O CD16 e o CD89 são FcRs com ITAM que apresentam uma dualidade na forma de ativação através do ITAM, que em algumas situações pode ser inibitória (ITAMi). Nessa tese reforçamos o papel chave da proteína wzxe, ligante do CD16, como responsável pela evasão bacteriana da E. coli através de sinalização ITAMi. Por outro lado, falhamos em demostrar diferenças após o tratamento de camundongos com lúpus induzido por pristane usando o peptídeo CYWGGTEGAC. Acreditamos que isso tenha ocorrido devido a dose inadequada do peptídeo ou proteólise por enzimas endógenas do camundongo, assim que o peptídeo é injetado. Novas doses ou a manipulação da estrutura do peptídeo são perspectivas futuras para este projeto. Quanto ao CD89, provamos seu papel extremamente importante na imunidade inata. Esse receptor, à semelhança do CD16, foi capaz de ligar-se diretamente a bactérias, na ausência de opsoninas e ligantes cognatos. O CD89 foi protetor tanto para infecção por gram-positivo quanto por gram-negativo enquanto o CD16 foi protetor apenas em modelo de pneumonia por gram-positivo / Introduction: Fc receptors are proteins of crucial importance in the health-disease process. They are responsible for the activation of effector mechanisms and modulate the immune and inflammatory responses. They play a central role in the pathogenesis of autoimmune diseases, sepsis and neoplastic diseases. Lupus, a prototype of autoimmune diseases and sepsis, a serious infection that causes organ dysfunction, are inflammatory diseases in which the role of Fc receptors has been unraveled. These pathologies have high morbidity and mortality, imposing enormous costs for society. E. coli has been found to bind directly to the FcGammaRIII(CD16) receptor to evade the immune system. This is due to the binding to the wzxe protein present in its membrane, making this receptor an interesting therapeutic target. CD16 is an FcGammaR with ITAM that classically has an activating function and generates inflammatory responses when binding to immunocomplexes. However, in sepsis, direct binding with E. coli induces an ITAMi activation, which blocks ROS production and inhibits phagocytosis and death of this bacterium. The manipulation of this apparently anti-inflammatory inhibitory signaling (ITAMi) may be an effective strategy for the treatment of inflammatory diseases such as sepsis and lupus. Initially we aimed to evaluate the physiological importance and therapeutic role of the CD16 binding peptide, in a sepsis model and pristane-induced lupus model, respectively. Similarly to CD16, CD89 (FcAlphaRI) is capable of mediating dual, activating or inhibitory signaling, which depends on how it binds to immunoglobulins and immunocomplexes. Therefore, we assessed whether FcAlphaRI (CD89) could bind to bacteria directly, in the absence of cognate ligands and mediate pro or anti-inflammatory responses, protecting or not the host. Methods: C57Bl/6 mice, WT and CD16KO with pristane-induced lupus were treated with the peptide CYWGGTEGAC (IRG Bioscience, USA). Gene and protein expression of cytokines, as well as genes associated to interferon signatures were evaluated in the lungs of these animals. We also used a sepsis model through the intra-peritoneal injection of E. coli WT and E. coli mutant wzxe-/-, in which we evaluated mortality and production of cytokines. We performed in vitro experiments with murine BMM and BMDC, human phagocytes and bacteria. Expression of CD89 and cognate receptors was assessed by flow cytometry. Flow cytometry with imaging was employed for phagocytosis analysis. In vivo experiments were also performed on WT and transgenic mice: CD89tg, CD89R209Ltg CD89tgCD16KO, CD16KO and CRPKO. We compared the mortality, cytokine production, amount of bacteria and tissue injury in CLP and pneumonia by nasal administration of S. pneumoniae. ROS production by BMM was evaluated with confocal microscopy and, in PMN, by chemiluminescence. Immunoprecipitation and immunoblotting were used to evaluate recruitment of syk and SHP-1. We used ELISA for binding assays with CD89 and bacteria and quantification of TNF-Aphla, IL-1 and IL-6. Results: Mice injected with wzxe-/- mutant E. coli survived more and produced smaller amounts of cytokines, reinforcing the key role of the wzxe protein in the mechanism of immune evasion of E. coli. WT and CD16KO pristane induced lupus mice, treated or not with the peptide CYWGGTEGAC didn\'t show differences in gene or protein expression of cytokines nor in interferon signature genes in their lungs. The bacterial-CD89 interaction in murine macrophages induces cellular activation, phagocytosis and bacterial death, which are dependent on the FcRGamma chain. This same interaction protects against mortality in two models of sepsis (CLP and pneumonia) and is dependent on the FcRGamma chain and independent of PCR and IgA anti-bacterium. Conclusions: CD16 and CD89 are ITAM-bearing FcRs that present a duality in the form of activation through ITAM, which in some situations may be inhibitory (ITAMi). In this thesis we reinforce the key role of wzxe protein, a CD16 ligand, as responsible for the bacterial evasion of E. coli through ITAMi signaling. On the other hand, we failed to demonstrate differences after treatment of pristane-induced lupus mice using the CYWGGTEGAC peptide. We believe that this was due to inadequate dose of the peptide or proteolysis by endogenous mouse enzymes, so the peptide is injected. New doses or manipulation of the peptide structure are future prospects for this project. As to CD89, we proved the extremely important role of CD89 in innate immunity. That receptor, similarly to CD16, was able to bind directly to bacteria, in the absence of opsonins and cognate ligands. CD89 was protective for both gram-positive and gram-negative infection while the CD16 was protective only in a model of gram-positive pneumonia
124

Identificação de peptídeos de Escherichia coli capazes de inibir a própria fagocitose em sepse / Identification of Escherichia coli peptides that can inhibit its own phagocytosis in sepsis

Beppler, Jaqueline 22 May 2015 (has links)
Introdução: Sepse é uma síndrome complexa definida por resposta inflamatória sistêmica, de origem infecciosa e caracterizada por manifestações múltiplas que podem determinar disfunção ou falência de um ou mais órgãos ou sistemas. É a principal causa de morte em unidades de terapia intensiva em pacientes críticos e tem representado uma fonte constante de preocupação para os sistemas de saúde em todo o mundo, devido, principalmente, às taxas elevadas de morbimortalidade. O tratamento da sepse é um desafio e continua a ser uma tarefa difícil devido a inúmeros fatores interferentes. Um estudo do nosso grupo demonstrou que a Escherichia coli (E. coli) é capaz de se ligar CD16 de um modo independente de opsonina, levando a um aumento na resposta inflamatória e a inibição da sua própria fagocitose, por conseguinte, procurou-se identificar os peptídeos no proteoma da E. coli envolvidos neste cenário. Metodologia: Utilizando a metodologia de Phage Display, que consiste numa técnica de clonagem, que permite a expressão de diversas sequências de peptídeos na superfície de bacteriófagos, nós identificamos 2 peptídeos que obtiveram interação com CD16. Após a seleção dos peptídeos identificamos uma proteína de membrana de E.coli que possui alta similaridade com um de nossos peptídeos selecionados. Nós acreditamos que esta proteína de membrana possa estar envolvida no processo de evasão imune desenvolvida pela E.coli e parece ser um forte candidato como uma nova opção terapêutica para controlar infecções por E. coli. Conclusão: A identificação de proteínas capazes de induzir inibição de fagocitose, através do receptor CD16, pode ser usada como uma nova forma de tratamento da sepse, assim como explorada no tratamento de doenças autoimunes / Introduction: Sepsis is a complex syndrome defined by a systemic inflammatory response of infectious origin and characterized by multiple manifestations that can determine dysfunction/failure of one or more organs and systems. It is the leading cause of death in intensive care units and represents a major health problem around the world, mainly due to its high mortality and morbidity rates. The treatment of sepsis is challenging and remains a difficult task due to numerous interfering factors. A study from our group demonstrated that Escherichia coli (E. coli) is able to bind CD16 in an opsoninindependent manner, leading to an increase in the inflammatory response and inhibition of its own phagocytosis, therefore we sought to identify the peptides in the E. coli proteome involved in this scenario. Methods and Results: Using the Phage Display technique, which is a cloning technique that allows the expression of various peptide sequences on the surface of bacteriophages (phages) and selecting these on the basis of affinity for a target molecule, we identified two peptides that interact with CD16. Next, using bioinformatic tools, we found an E. coli membrane protein that has high similarity with one of our selected peptides. We believe this membrane protein is involved in the process of immune evasion developed by E. coli and it is a strong candidate as a new therapeutic option to control E. coli infections. Conclusion: The identification of proteins capable of inducing inhibition of phagocytosis through the CD16 receptor, can be used as a new treatment of sepsis, as well as exploited in the treatment of autoimmune diseases
125

Identificação de peptídeos de Escherichia coli capazes de inibir a própria fagocitose em sepse / Identification of Escherichia coli peptides that can inhibit its own phagocytosis in sepsis

Jaqueline Beppler 22 May 2015 (has links)
Introdução: Sepse é uma síndrome complexa definida por resposta inflamatória sistêmica, de origem infecciosa e caracterizada por manifestações múltiplas que podem determinar disfunção ou falência de um ou mais órgãos ou sistemas. É a principal causa de morte em unidades de terapia intensiva em pacientes críticos e tem representado uma fonte constante de preocupação para os sistemas de saúde em todo o mundo, devido, principalmente, às taxas elevadas de morbimortalidade. O tratamento da sepse é um desafio e continua a ser uma tarefa difícil devido a inúmeros fatores interferentes. Um estudo do nosso grupo demonstrou que a Escherichia coli (E. coli) é capaz de se ligar CD16 de um modo independente de opsonina, levando a um aumento na resposta inflamatória e a inibição da sua própria fagocitose, por conseguinte, procurou-se identificar os peptídeos no proteoma da E. coli envolvidos neste cenário. Metodologia: Utilizando a metodologia de Phage Display, que consiste numa técnica de clonagem, que permite a expressão de diversas sequências de peptídeos na superfície de bacteriófagos, nós identificamos 2 peptídeos que obtiveram interação com CD16. Após a seleção dos peptídeos identificamos uma proteína de membrana de E.coli que possui alta similaridade com um de nossos peptídeos selecionados. Nós acreditamos que esta proteína de membrana possa estar envolvida no processo de evasão imune desenvolvida pela E.coli e parece ser um forte candidato como uma nova opção terapêutica para controlar infecções por E. coli. Conclusão: A identificação de proteínas capazes de induzir inibição de fagocitose, através do receptor CD16, pode ser usada como uma nova forma de tratamento da sepse, assim como explorada no tratamento de doenças autoimunes / Introduction: Sepsis is a complex syndrome defined by a systemic inflammatory response of infectious origin and characterized by multiple manifestations that can determine dysfunction/failure of one or more organs and systems. It is the leading cause of death in intensive care units and represents a major health problem around the world, mainly due to its high mortality and morbidity rates. The treatment of sepsis is challenging and remains a difficult task due to numerous interfering factors. A study from our group demonstrated that Escherichia coli (E. coli) is able to bind CD16 in an opsoninindependent manner, leading to an increase in the inflammatory response and inhibition of its own phagocytosis, therefore we sought to identify the peptides in the E. coli proteome involved in this scenario. Methods and Results: Using the Phage Display technique, which is a cloning technique that allows the expression of various peptide sequences on the surface of bacteriophages (phages) and selecting these on the basis of affinity for a target molecule, we identified two peptides that interact with CD16. Next, using bioinformatic tools, we found an E. coli membrane protein that has high similarity with one of our selected peptides. We believe this membrane protein is involved in the process of immune evasion developed by E. coli and it is a strong candidate as a new therapeutic option to control E. coli infections. Conclusion: The identification of proteins capable of inducing inhibition of phagocytosis through the CD16 receptor, can be used as a new treatment of sepsis, as well as exploited in the treatment of autoimmune diseases
126

Vedení a řízení vybraných fotbalových klubů a specifika jejich fungování / Management and leadership of the selected football clubs and specific features of their functioning

Podzimek, David January 2017 (has links)
The recent departure of Czech football clubs participating in the top two competitions for the newly created League of Football Association (LFA) has given rise to a number of questions. This step is generally considered to be a significant step towards emphasising the differences between the professional and amateur areas of football in our country. The goal of this dissertation was to demonstrate the differences and the similar features in the management and leadership of this type of sports organisation on the basis of practical research undertaken in two selected clubs. FC Jablonec nad Nisou from the first division served as an example of the professional sphere, while FC Loko Vltavín was selected as a representative of the amateur game. The findings were then used to compare these two kinds of clubs in relation to various aspects of their complex functioning. General principles and specific features have been drawn from this for both qualitative levels. The results have particularly demonstrated the significant influence of club economics and the competitive environment, which mutually influence and to a certain degree determine the level of all other areas which the people from the club management are involved in.
127

Étude de la mise en oeuvre de composites thermostables cyanate-ester pour pièces structurales aéronautiques tièdes / Study of thermostable cyanate-ester composite for warm aircraft structural parts

Zemni, Lilia 14 March 2019 (has links)
Les pièces situées dans des zones chaudes/tièdes (300-400°C) de l'avion sont actuellement en titane (mât moteur) ou en composite à matrice époxy (plenum). Comment pourrait-on diminuer la masse de ces pièces tout en évitant leur dégradation à hautes températures de fonctionnement ? Le projet TACT (Technologie pour Aérostructures composites Tièdes), porté par Nimitech Innovation® (Groupe LAUAK), propose une solution innovante consistant à mettre en oeuvre par voie RTM des pièces structurales tièdes à base de renfort en fibres de carbone (FC) et de matrice Cyanate ester (CE). Le choix de la matrice thermodurcissable CE est justifié par son caractère thermostable, c'est-à-dire sa capacité d'opérer en continu à de hautes températures de fonctionnement (avec une température de transition vitreuse Tg>300°C). Par ailleurs, elle possède la facilité de mise en oeuvre des époxydes du fait qu'elle s'adapte généralement bien aux paramètres du procédé RTM. Toutefois, l'exothermie élevée de la matrice CE lors de la réticulation implique un gradient de température dans la pièce composite et peut ainsi engendrer des problèmes de surchauffe. Les travaux scientifiques menés dans le cadre de cette thèse se focalisent sur la problématique de surchauffe de la résine pendant le processus de polymérisation très exothermique dans le moule RTM. L'objectif serait ainsi de maîtriser le cycle de cuisson du composite afin d'éviter tout problème d'emballement ou de dégradation pendant la réticulation de la matrice. Dès lors, la thèse s'organise de la manière suivante : dans un premier temps, le comportement thermocinétique de la matrice CE (pure et catalysée) est analysé pendant l'étape de réticulation, et ceci dans l'optique de contribuer à l'optimisation de cycle de cuisson lors de la mise en oeuvre du composite FC/CE par procédé RTM. Ensuite, les propriétés thermiques (capacité calorifique, conductivité, diffusivité) en fonction du degré d'avancement de la résine CE sont menés afin d'évaluer le gradient thermique régi par l'équation de la chaleur permettant de maîtriser la cuisson de la résine dans l'épaisseur. Par ailleurs, la vitrification de la matrice CE est étudiée par le suivi de la température de transition vitreuse Tg en fonction de la température et du taux d'avancement à l'aide de différents techniques de mesure (DSC, DMA, TMA). Enfin, une modélisation de la vitrification à l'aide du modèle Di-Benedetto permettra l'estimation de la température de la transition vitreuse Tg ∞ pour le réseau tridimentionnel entièrement réticulé. / Aeronautical parts which operate in high temperature area (300-400°C) are currently made of titanium (aircraft pylon) or composite materials based on epoxy matrix (plenum). In which extent the weight of these pieces could be reduced as well as avoiding their degradation when operating at these working temperature ranges? TACT project (Technologie pour Aérostructures composites Tièdes), overseen by Nimitech Innovation® (Groupe LAUAK), suggests an innovative solution based on the development of high performance composites parts reinforced by carbon fibers (CF) and cyanate ester matrix (CE) through RTM process. The CE resin belongs to the class of high-performance thermosetting polymers and is mainly chosen in this project due to its thermal stability when operating at high temperatures (with a glass transition Tg>300°C), as well as epoxy-like processability. However, the cross-linking reaction exhibits highly exothermic process, resulting in non-linear increase in internal temperature, which may cause a temperature overshoot. The scientific work carried out within this thesis focuses on the problem of overheating of the resin during the highly exothermic polymerization process in the RTM mold. The objective would thus be to control the curing cycle of the composite in order to avoid problems of runaway or degradation during the crosslinking of the matrix. Hence, the thesis is organized as follows: firstly, thermokinetic behavior of CE resin is analyzed during the crosslinking process in order to optimize the curing cycle. Secondly, thermal properties (heat capacity, conductivity, diffusivity) are identified as a function of the conversion degree in order to evaluate the thermal gradient covered by the heat equation making it possible to control the curing along the thickness of the composite. Moreover, the vitrification of the cyanate ester matrix is studied by monitoring the glass transition temperature Tg as a function of the temperature and conversion degree using different methods (DSC, DMA, TMA). Finally, Di-Benedetto model, a vitrification model, is chosen in order to identify the glass transition temperature Tg∞ of a full crosslinked resin.
128

Microbial contamination in the surface water in the Ba Vi National Park, Ha Noi

Le, Nhu Da, Phung, Thi Xuan Binh, Le, Thi Phuong Quynh 07 February 2019 (has links)
Ba Vi National Park, one of 28 Vietnam National parks, is currently preserved and exploited for a variety of purposes, including the preservation of intact natural forest ecosystems and genetic resources of rare plants and animals. This paper presents the monitoring results of microbial contamination in surface water environment of the Ba Vi National Park (Ha Noi) in the period 2013-2014 and 2018. The results showed that total coliform (TC) density varied from 23 to 11,000 MPN/100ml in bimonthly observation in 2013-2014 which was lower than that one of sampling campaign in 2018, from 900 MPN/100ml to 8,100 MPN/ml. Fecal coliform (FC) densities vaired from 0 to 110 MPN/100ml in 2013 -2014 were lower than that in 2018, from 0 MPN/100ml to 600 MPN/100ml. At several observation time, both TC and FC were higher than the allowable values of the Vietnam national technical regulation QCVN 08-MT: 2015/BTNMT column A1 for surface water quality. The exceeded values of TC and FC than the allowable values and the increase trend from the 2013 to 2018 periods indicated the potential risks to the public health in this region when people use water for domestic and agricultural purposes. Our results provide dataset for environmental management in the Ba Vi National Park in order to protect the eco-environment in parallel with economical-social development. / Vườn Quốc gia Ba Vì, một trong 28 vườn quốc gia của Việt Nam hiện đang được bảo tồn và khai thác cho nhiều mục đích, trong đó có bảo tồn nguyên vẹn các hệ sinh thái rừng tự nhiên, các nguồn gen động, thực vật quý hiếm, các đặc sản rừng và các di tích lịch sử, cảnh quan tự nhiên trong vùng. Bài báo trình bày kết quả quan trắc, đánh giá mức độ ô nhiễm vi sinh vật trong môi trường nước mặt tại Vườn Quốc Gia Ba Vì, Hà Nội giai đoạn 2013-2014 và 2018. Kết quả cho thấy mật độ coliform tổng số (TC) biến đổi trong khoảng từ 23 – 11.000 MPN/100ml trong các đợt quan trắc định kỳ 2 tháng/lần trong hai năm 2013 - 2014 và trong khoảng từ 900 – 8.100 MPN/100ml trong một đợt quan trắc năm 2018. Mật độ fecal coliform (FC) biến đổi trong khoảng từ 0 - 110 MPN/100ml năm 2013 -2014 và từ 0 - 600 MPN/100ml vào năm 2018. Vào một số thời điểm quan trắc, mật độ FC và TC vượt giá trị cho phép của quy chuẩn kỹ thuật Quốc Gia QCVN 08-MT:2015/BTNMT cột A1 về chất lượng nước mặt. Các giá trị TC và FC vượt quá giá trị cho phép và xu hướng gia tăng TC và FC từ 2013 -2018 cho thấy nguy cơ tiềm tàng khi người dân sử dụng nguồn nước này cho các mục đích sinh hoạt và nông nghiệp. Như vậy, kết quả của nghiên cứu này nhấn mạnh nhu cầu giám sát thường xuyên chất lượng nước và cần thực hiện các giải pháp hiệu quả để xử lý và quản lý nguồn gây ô nhiễm trong khu vực nhằm bảo vệ môi trường sinh thái song song với phát triển kinh tế - xã hội của khu vực.
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Immunomodulatory Therapy of Solid Tumors : With a Focus on Monoclonal Antibodies

Sandin, Linda January 2013 (has links)
Cancer, historically considered a genetic disease, is currently acknowledged to affect the whole body. Our immune system is one key player that can elicit a response against malignant cells but can also promote tumorigenesis. Tumors avoid immune recognition by creating a suppressive microenvironment and inducing tolerance. T-cells are regarded a major effector cell type in tumor immunotherapy. An important ”switch” needed for T-cell activation involves so-called costimulatory and coinhibitory receptors. In this thesis, experimental tumor models were used to investigate the potential of immunomodulatory antibodies to stimulate immune cells and subsequently eliminate tumors. First, systemic antibody blockade of two negative checkpoint regulators (CTLA-4 and PD-1) present on T-cells was evaluated in combination with local CpG therapy or standard BCG treatment. Indeed, this combinatorial therapy with CpG augmented anti-tumor effects with increased levels of tumor-directed T-cells and reduced tumor-infiltrating Tregs. Secondly, as these immunomodulatory antibodies elicit severe side effects in patients, a local low-dose delivery regimen was explored as an alternative to systemic bolus treatment. Our results demonstrated that an approximately seven times lower dose of aCTLA-4, compared to systemic delivery, could eradicate both primary and distant tumors. CD40-expressing APCs are another potential target in antibody-mediated cancer therapy. CD40-stimulated dendritic cells (DCs) have the capability to activate tumor-directed T-cells to kill tumor cells. We next sought to investigate agonistic CD40 antibody efficacy and in vivo biodistribution when delivered locally compared to the equivalent systemic dose. Anti-tumor effects were dependent on CD8+ T-cells, host CD40 expression and the presence of tumor antigen at the injection site. CD40 antibodies were cleared from the circulation and accumulated in lymphoid organs, where, upon repeated aCD40 dosing, target APC populations increased in numbers and upregulated their surface CD40 expression. Lastly, CD40 agonist antibodies were mixed with nanoparticles to enhance their stimulatory properties. B-cells demonstrated increased proliferative capacity and DCs became more activated when exposed to the cocktail. Further, this combination reduced serum levels of pro-inflammatory cytokines compared to plain antibodies.       The results herein advocate further exploratory studies of the delivery of monoclonal antibodies at the tumor site in order to improve anti-tumor effects and reduce toxicity.
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Characterisation of the effect and functional significance of Fcγ receptor crosslinking on metabolic processes in macrophages

Jing, Chenzhi January 2018 (has links)
The metabolic state of an immune cell directly influences its ability to function and differentiate, ultimately affecting immunity, inflammation and tolerance. Different immune cell subsets have differing metabolic requirements. Macrophages, as the frontline, tissue-resident cells of the innate immune system, undergo profound metabolic reprogramming in response to environmental stimuli. To date, there has been little consideration how macrophage metabolism might be affected by humoral immunity. IgG antibodies are the soluble effector molecules of the adaptive humoral immune system. Fcγ receptors (FcγRs) mediate the cellular functions of IgG antibodies and are expressed on most immune cells including macrophages. FcγR cross-linking induced by IgG immune complexes (ICs) is important for defence against some infections but can also play a pathogenic role in autoimmunity. Here, I studied the metabolic reprogramming induced in macrophages by IgG IC ligation of FcγRs. I first investigated how FcγRs cross-linking might impact glucose metabolism. We show that macrophages undergo a switch to glycolysis in response to IgG IC stimulation. FcγR-associated glycolysis was dependent on the mammalian target of rapamycin (mTOR) and hypoxia-inducible factor (HIF)1α. Moreover, this glycolytic switch was required to generate a number of pro-inflammatory mediators and cytokines. Inhibition of glycolysis, or genetic depletion of HIF1α in macrophages resulted in the attenuation of IL1β and other inflammatory mediators produced in response to IgG IC in vitro. To determine the relevance of these observations to responses to IgG IC in vivo and, in particular, to IC-associated tissue inflammation in autoimmune diseases such as system lupus erythematosus (SLE), I developed three models to interrogate tissue macrophages. Following administration of IC to peritoneal macrophages, I observed IL1β-associated neutrophil recruitment that was abrogated by inhibiting glycolysis, or in the presence of HIF-1a deficiency. Similarly, following administration of intravenous IC, or nephrotoxic serum, kidney macrophage activation was abrogated by glycolysis inhibition or by myeloid HIF-1a deficiency. Together my data reveal the cellular molecular mechanisms required for FcγR-mediated metabolic reprogramming in macrophages and define a novel therapeutic strategy in autoantibody-induced inflammation. In the final part of the thesis I identified additional metabolic pathways that were altered by FcγR ligation, including cholesterol biosynthesis and fatty acid biosynthesis. This has important implications for protective immune responses and autoimmune susceptibility, since a number of intermediates in these pathways can directly regulate and contribute to immune responses. In summary, I have demonstrated the metabolic alterations triggered by FcγR ligation, reveal the cellular molecular mechanisms required for FcγR-mediated cellular respiration reprogramming in macrophages and define a potential therapeutic target in autoimmunity.

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