Caractérisation de l'activité fonctionnelle et métabolique des cellules NK en situation de stress nutritionnels : approche expérimentale in vitro et in vivo

Natural killer (NK) cells are critical mediators of anti-tumor immunity. A high-calorie diet inducing obesity is associated with breast cancer development. NK cells are modulated by dietary and metabolic factors and a decrease in their lytic activity promotes mammary tumor development. In the breast microenvironment, high concentration of leptin can be secreted by mammary adipocytes and thereby could stimulate tumor growth and control immune cells. Arginine, strongly consumed by tumor and myeloid-derived suppressor cells, could be lacking to NK cells. The aim of this work is to characterize the functional and metabolic activities of NK cells in response to nutritional stress. Initially, we explored in vivo the impact of a high-calorie diet on NK cells activity and mammary tumor development. Then, we identified potential functional alterations in NK cells by mimicking the conditions found in the tumor microenvironment such as the presence of high leptin concentration and arginine depletion. Female Balb-c nude mice were fed a high-caloric diet (HC) versus a standard caloric diet (SC) for 6 months. After five months, mammary tumor cells (MCF-7, SCT, HCT) or MatrigelTM (SC, HC) were implanted into the fourth mammary fat pads. The tumor development in HC diet-fed mice was associated with a decrease in body weight, body fat and lean mass and an increase in volume and weight of tumors. This diet induced tumor over-expression, at the transcriptional level, of enzymes involved in glycolysis and a down-expression of citrate cycle actors. Protein tumor levels of cleaved caspase 3, estrogen β and progesterone receptors were reduced while Ki67 was increased in the HC diet-fed mice. NK cell cytotoxicity of HC diet-fed mice was reduced. Although the presence of tumor stimulated NK cell lytic activity, this later was lower in the HCT group compared to the one of SCT mice. In vitro, leptin stimulated, in dose-dependent manner, the metabolic activity of NK cells. High leptin concentrations enhanced NK cell cytotoxicity against the MDA-MB-231 target cells. This phenomenon involved the increase of expression of TRAIL and IFN-γ in NK cells. However, against the MCF-7 target cells, NK cell lytic activity was reduced in the presence of high concentrations of leptin, probably in link to the decreased perforin expression. NK cell proliferation and cytotoxicity were impaired in response to arginine depletion. This inhibition of NK cell cytotoxicity could be linked to a low target cells recognition by NKp46 and NKp30, a reduced activating signal transmission by ζ chain and a low production of IFN-γ. Thus, high energy intake promotes mammary tumor development in particular by inhibiting NK cell cytotoxicity. In vitro, high leptin concentrations stimulate or reduce NK cell cytotoxicity according to the breast cancer cell targets. Furthermore, arginine depletion inhibits NK cell proliferation and cytotoxicity in vitro. These findings provide insight into the microenvironment impacts on NK cell antitumor response in tumor development.Les cellules Natural Killer (NK), actrices majeures de la vigilance anti-tumorale, sont modulées par des facteurs nutritionnels et métaboliques. L'inhibition de leur activité favorise le développement tumoral. Un régime alimentaire hypercalorique induisant l'obésité est un facteur de risque de développer un cancer du sein. Au niveau du micro-environnement tumoral mammaire, la biodisponibilité en certaines molécules contrôle non seulement les cellules néoplasiques mais, également les cellules immunes infiltrées. Ainsi, la leptine, sécrétée à forte concentration par les adipocytes mammaires, pourrait favoriser la croissance tumorale et altérer les cellules NK. L'arginine fortement consommée par les cellules tumorales et les cellules suppresseurs dérivées des myéloïdes pourrait faire défaut aux cellules NK. L'objectif de cette thèse est de caractériser les activités fonctionnelles et métaboliques des cellules NK en situation de stress nutritionnel. Dans un premier temps, nous avons exploré, in vivo, l'impact d'un régime hypercalorique sur l'activité des cellules NK et sur le développement tumoral mammaire. Ensuite, nous avons cherché à identifier les potentielles altérations fonctionnelles des cellules NK en mimant, in vitro, les conditions retrouvées au niveau du micro-environnement tumoral telles que la présence de concentration élevée en leptine et la déplétion en arginine. Des souris Balb-c "nude" femelles ont été soumises à un régime hypercalorique (HC) versus une diète normo-calorique (NC) pendant 6 mois. Au bout de 5 mois, des cellules tumorales mammaires (MCF-7 ; groupes NCT et HCT) ou le véhicule (groupes NC et HC) ont été implantés au niveau de la quatrième paire de glandes mammaires. Sous régime HC, le développement tumoral s'accompagne d'une perte de masse grasse, de masse maigre et de poids corporel avec un volume et un poids de tumeur augmentés. Cette diète induit au niveau tumoral une sur-expression des ARNm d'enzymes impliquées dans la glycolyse et une sous-expression des acteurs du cycle de Krebs. Sous régime HC, l'expression de la caspase 3 clivée et des récepteurs des oestrogènes β et de la progestérone est réduite alors que celle du Ki67 est accrue. Les cellules NK des souris HC ont une cytotoxicité diminuée. Bien que la présence de tumeur stimule l'activité lytique des cellules NK, la cytotoxicité de ces cellules reste inférieure dans le groupe HCT comparativement à celle du groupe NCT. La leptine stimule, in vitro, de façon dose-dépendante l'activité métabolique des cellules NK. A fortes concentrations, elle active leur cytotoxicité vis-à-vis des cellules cibles MDA-MB-231. Cet effet passe par une stimulation de l'expression de TRAIL et de l'IFN-γ par les cellules NK. En revanche, vis-à-vis des cellules cibles MCF7, les cellules NK présentent une activité lytique réduite en présence de fortes concentrations de leptine, probablement en lien avec une réduction de l'expression de la perforine. En réponse à une déplétion en arginine dans le milieu de culture, la prolifération et la cytotoxicité des cellules NK sont abaissées. L'altération de la reconnaissance des cellules cibles par les récepteurs NKp46 et NKp30, la moindre transmission du signal activateur par la chaine ζ et la faible production d'IFN-γ peuvent expliquer l'inhibition de la cytotoxicité des cellules NK. Ainsi, un apport énergétique élevé favorise le développement tumoral mammaire notamment eninhibant la cytotoxicité des cellules NK. De plus, la leptine à fortes concentrations stimule ou réduit, in vitro, la cytotoxicité des cellules NK selon la nature des cellules cancéreuses mammaires cibles. Une déplétion en arginine, in vitro, quant à elle, inhibe la prolifération et la cytotoxicité des cellules NK. Ces travaux contribuent à mieux comprendre l'impact du micro-environnement sur la réponse antitumorale des cellules NK

Optimização de aproveitamento de condensados em sistemas energéticos

Mestrado em Engenharia MecânicaNos últimos anos tem-se assistindo a um aumento do consumo de energia devido ao desenvolvimento socioeconómico dos países e ao aumento da população global. De forma a auxiliar o aumento do consumo de energia têm se desenvolvido técnicas de análise com o objectivo principal de optimizar os consumos energéticos nos processos produtivos. Inicialmente dois métodos de análise e optimização de redes térmicas são analisadas e comparadas. Estas análises, Pinch e Termoecnómica, revelaram grandes potencialidades na obtenção de melhorias, sendo a pinch a metodologia seleccionada para implementação no caso de estudo, por se tratar de uma área com alguma carência de especialistas e de implementação sistemática, o que facilita na busca por melhorias. Neste trabalho é realizada uma análise de eficiência energética a uma rede de fluidos térmicos real através da tecnologia pinch. Este tipo de análise permite a definição de metas que motivam o projectista na pesquisa por melhores soluções de recuperação de energia entre as correntes de processo. As metas inicialmente calculadas pela tecnologia pinch são ultrapassadas devido ao máximo aproveitamento dos permutadores existentes que permitem o aumento da temperatura de uma determinada corrente para além do seu ponto pinch. Com a implementação desta metodologia foi possível a obtenção de duas situações de melhoria que revelam o potencial deste tipo de análise ao se constatar que não existe apenas uma situação óptima, podendo optar-se por propostas com melhores resultados a nível energético ou económico. No caso de estudo foi possível obter reduções na ordem de 1010 kg/h de vapor o que implica uma redução 17% do consumo anual de vapor. A redução na factura energética anual é de aproximadamente 98.000,00. Para a obtenção destas reduções é necessária a aquisição de permutadores de calor com tempo de retorno de investimento entre 2 e 3 meses o que torna as duas situações muito atractivas. Nas duas situações propostas obteve-se reduções de cerca de 8% do consumo específico da instalação em estudo podendo esta cumprir os novos planos de racionalização (SGCIE) e obter os benefícios fiscais conseguidos pelo cumprimento destes. ABSTRACT: In recent years an increase of the energy consumption was verified, this is caused by the socio-economic development of the countries and the increase of global population. In order to assist the increase of energy consumption, techniques were developed to optimize these consumptions in productive processes. Initially two methods of analysis and optimization of thermal systems were analyzed and compared. These analyzes, Pinch and Thermoeconomic had disclosed great potentialities in the attainment of improvements, Pinch methodology was the selected one to implement in the study case, it was chosen because it’s an area with a lack of specialists and the possibility of systematic implementation. In this work is made an analysis of energetic efficiency to a real thermal fluid net through the Pinch technology. This type of analysis allows the definition of targets that motivate the developer in the research for better solutions of energy recovery in process chains. The initially calculated energy targets by pinch technology were exceeded because of the maximum exploitation of the existing exchangers that allow the increase of temperature in a current beyond its point pinch By implementing this methodology it was possible to obtain two improvement situations, what reveal the potential of Pinch analysis, being possible to find several proposals of performing with great results at energetic or economic level. In study case it was achieved reductions in the order of 1010kg/h of steam, which implies a 17% reduction in the annual consumption. The reduction in annual energy bill is approximately € 98,000.00. To obtain these reductions, the company must acquire heat exchangers, which the return of investment is between 2 and 3 months, that makes the proposes very attractive. In this two proposals situations, one obtained reductions close to 8% of the specific consumption of installation in study being able to fulfill the new plans of rationalization (SGCIE) and obtaining tax benefits by the fulfilment of these

Desenvolvimento e caracterização de nanofluidos para intensificação de transferência de calor

Doutoramento em Engenharia MecânicaA desmaterialização da economia é um dos caminhos para a promoção do desenvolvimento sustentável na medida em que elimina ou reduz a utilização de recursos naturais, fazendo mais com menos. A intensificação dos processos tecnológicos é uma forma de desmaterializar a economia. Sistemas mais compactos e mais eficientes consomem menos recursos. No caso concreto dos sistemas envolvendo processo de troca de calor, a intensificação resulta na redução da área de permuta e da quantidade de fluido de trabalho, o que para além de outra vantagem que possa apresentar decorrentes da miniaturização, é um contributo inegável para a sustentabilidade da sociedade através do desenvolvimento científico e tecnológico. O desenvolvimento de nanofluidos surge no sentido de dar resposta a estes tipo de desafios da sociedade moderna, contribuindo para a inovação de produtos e sistemas, dando resposta a problemas colocados ao nível das ciências de base. A literatura é unânime na identificação do seu potencial como fluidos de permuta, dada a sua elevada condutividade, no entanto a falta de rigor subjacente às técnicas de preparação dos mesmos, assim como de um conhecimento sistemático das suas propriedades físicas suportado por modelos físico-matemáticos devidamente validados levam a que a operacionalização industrial esteja longe de ser concretizável. Neste trabalho, estudou-se de forma sistemática a condutividade térmica de nanofluidos de base aquosa aditivados com nanotubos de carbono, tendo em vista a identificação dos mecanismos físicos responsáveis pela condução de calor no fluido e o desenvolvimento de um modelo geral que permita com segurança determinar esta propriedade com o rigor requerido ao nível da engenharia. Para o efeito apresentam-se métodos para uma preparação rigorosa e reprodutível deste tipo de nanofluido assim como das metodologias consideradas mais importantes para a aferição da sua estabilidade, assegurando deste modo o rigor da técnica da sua produção. A estabilidade coloidal é estabelecida de forma rigorosa tendo em conta parâmetros quantificáveis como a ausência de aglomeração, a separação de fases e a deterioração da morfologia das nanopartículas. Uma vez assegurado o método de preparação dos nanofluídos, realizou-se uma análise paramétrica conducente a uma base de dados obtidos experimentalmente que inclui a visão central e globalizante da influência relativa dos diferentes fatores de controlo com impacto nas propriedades termofísicas. De entre as propriedades termofísicas, este estudo deu particular ênfase à condutividade térmica, sendo os fatores de controlo selecionados os seguintes: fluido base, temperatura, tamanho da partícula e concentração de nanopartículas. Experimentalmente, verificou-se que de entre os fatores de controlo estudados, os que maior influência detêm sobre a condutividade térmica do nanofluido, são o tamanho e concentração das nanopartículas. Com a segurança conferida por uma base de dados sólida e com o conhecimento acerca da contribuição relativa de cada fator de controlo no processo de transferência de calor, desenvolveu-se e validou-se um modelo físico-matemático com um caracter generalista, que permitirá determinar com segurança a condutividade térmica de nanofluidos.The economy dematerialization is a means to promote sustainable development as it eliminates or reduces the use of natural resources. Hence, the intensification of technological processes is a way to dematerialize the economy. More compact and efficient systems require fewer resources. In what concerns technological systems involving heat exchange processes, intensification results in the reduction of the exchanging area and amount of working fluid, which in addition to other advantages inherent to systems’ miniaturization, is a direct contribution of the scientific and technological development to a more sustainable society. The development of nanofluids is a response to such challenges of contemporary society, contributing to the innovation of products and systems by solving fundamental questions raised at the level of basic sciences. The available literature is unanimous identifying nanofluids potential as an engineering thermal fluid due to their thermo-physical properties, namely a high thermal conductivity. However, the lack of rigorous preparation techniques as well as of a systematic knowledge of their thermo-physical properties, supported by validated physical-mathematical models, are serious constrains to their use in engineering applications. In this work, the thermal conductivity of carbon nanotubes, water based nanofluids were systematically studied. The governing physical mechanisms for heat conduction in the nanofluid were established as the basic condition for the development of a general model able to securely determine this property with the precision required in engineering applications. For this purpose the methodologies to correctly prepare such nanofluids in a reproducible way as well as to measure their long term stability are presented. The colloidal stability is accurately established and quantified taking into account parameters such as the absence of agglomeration, separation of phases and deterioration of the morphology of the nanoparticles. A parametric analysis was developed through appropriate DOE methodologies in order to build a comprehensive data base of the nanofluid physical properties as a function of control factors, previously identified variables considered to have the greatest impact on the variability of thermo-physical properties. Among the latter, this work gives particular attention to the acquisition of thermal conductivity data against the selected control factors: base fluid, temperature, size and concentration of nanoparticles. It was verified experimentally that amongst these control factors, those that hold the greatest influence on the thermal conductivity of the nanofluid are the size and concentration of nanoparticles. A solid database and the awareness about the relative contribution of each mechanism controlling the heat transfer process in nanofluids successfully supported the development and validation of a general physical-mathematical model to determine the thermal conductivity of nanofluids

Nanoparticules dans l’alimentation - Interactions avec le microbiote intestinal, impacts sur la fonction barrière de l’intestin et devenir systémique.

Ce numéro est constitué d’articles issus du colloque « Contaminants alimentaires – approches émergentes pour connaître et prévenir le risque » qui s’est tenu à Paris le 19 décembre 2018.Nanotechnologies in food refer to the use of nanoparticles (NPs, <100 nm) added directly to foodstuffs(food additives, encapsulation of ingredients), incorporated into their packaging to gain in barrierproperties (e.g., biocidal) or as sensors for unwanted substances (pathogens or toxins). Whetherintentionally added in food or in contact via their packaging, oral NPs are suspected of being at risk forhealth. Nanodimension facilitates the passage of biological barriers like the intestine. NPs accumulate inthe liver, spleen and brain where their high chemical reactivity is a source of potentially toxic effects. Inthe intestine, the chronic consequences on the ecology and/or the metabolic activity of the microbiotaare unknown. Like the nano-silver, their bactericidal properties are likely to weaken the host healthgiven the importance of the gut microbiota in the development and balance of digestive, immune,metabolic, and brain functions. In view of the current or promised applications of NPs in ultra-processedfoodstuffs, it is necessary to evaluate the risks associated with their ingestion. This involves assessingthe long-term effects on the gut microbiota and intestinal barrier function, the absorption pathways andthe characterization of the danger potential(s) related to their bioaccumulation in the bodyLes nanotechnologies dans l’alimentation recouvrent l’utilisation de nanoparticules (NPs, <100 nm)ajoutées directement à des denrées (additifs, encapsulation d’ingrédients), incorporées dans leursemballages pour leur conférer des propriétés de barrière aux intrants (e.g., biocide) ou comme capteursd’indésirables (pathogènes ou toxines). Qu’elles soient intentionnellement ajoutées dans les alimentsou au contact via leur emballage, les NPs sont soupçonnées de risques pour la santé. Lananodimension facilite le passage des barrières biologiques comme l’intestin. Des NPs s’accumulentdans le foie, la rate et le cerveau où leur forte réactivité chimique est source d’effets potentiellementtoxiques. Dans l’intestin, les conséquences chroniques sur l’écologie et/ou l’activité métabolique dumicrobiote sont méconnues. A l’exemple du nano-Argent, leurs propriétés bactéricides sontsusceptibles de fragiliser la santé de l’hôte compte tenu de l’importance du microbiote intestinal dans ledéveloppement et l’équilibre des fonctions digestives, immunitaires, métaboliques, cérébrales. Face auxapplications actuelles ou promises des NPs dans des produits ultra-transformés, il est nécessaired’évaluer les risques liés à leur ingestion. Cette démarche passe par l’évaluation des effets à long termesur le microbiote et la fonction de barrière intestinale, les voies d’absorption et la caractérisation dupotentiel de danger(s) lié à leur bioaccumulation dans l’organisme

Saberes y percepciones en torno al Paisaje Cultural de Laguna de Rocha

La presente propuesta busca compartir y reflexionar en torno al trabajo realizado y los espacios de intercambios generados con diferentes actores en el marco de proyectos de extensión universitaria e investigación en el Paisaje Cultural del Paisaje Protegido Laguna de Rocha (PPLR). La misma se enmarca dentro del Laboratorio de Arqueología del Paisaje y Patrimonio (LAPPU) del Departamento de Arqueología de la Facultad de Humanidades y Ciencias de la Educación, unidad asociada al Centro Universitario Regional Este (CURE). Los procesos de intercambio permanentes y la trayectoria por parte del equipo en la zona han permitido pensar nuevas formas de acción que contemplen las miradas y contribuyan al desarrollo de una conciencia colectiva en relación al patrimonio. En particular esta ponencia busca compartir la experiencia en torno a la cartografía social y su análisis como herramienta que permite visualizar e incorporar diferentes perspectivas, miradas del territorio y representaciones, centrados en particular en el patrimonio local (patrimonio vivo y arqueológico). Producto de las cartografías sociales realizadas y las dimensiones significativas abordadas en los ejes temáticos establecidos y su análisis, se generaron espacios de intercambio con los actores locales que han permitido conocer e integrar distintos saberes, miradas y percepciones, así como reflexionar sobre los patrimonios y memorias locales y proponer nuevas estrategias para su puesta en valor, socialización y apropiación social. De esta forma se van fortaleciendo y consolidando redes y vínculos entre actores universitarios y pobladores locales, socializando intereses, percepciones en torno al PPLR como aporte a la construcción de los componentes del Objeto Focal Paisaje Cultural.GT50: Antropólogxs y arqueólogxs en proyectos de extensión universitaria y de comunicación científica. Redes, apropiaciones y tensiones.Universidad Nacional de La Plat

Benznidazole

The conformation of the title compound [systematic name: N-benzyl-2-(2-nitro­imidazol-1-yl)acetamide], C12H12N4O3, can be described in terms of the relative orientation of three planar fragments, the imidazol group (A), benzyl group (B), and the acetamide fragment (C), with corresponding dihedral angles: A/C = 88.17 (4), B/C = 67.12 (5) and A/B = 21.11 (4)°. The crystal packing is enhanced by a network of strong inter­molecular N—H⋯O hydrogen bonds

Optimal quantum cloning of orbital angular momentum photon qubits via Hong-Ou-Mandel coalescence

The orbital angular momentum (OAM) of light, associated with a helical structure of the wavefunction, has a great potential for quantum photonics, as it allows attaching a higher dimensional quantum space to each photon. Hitherto, however, the use of OAM has been hindered by its difficult manipulation. Here, exploiting the recently demonstrated spin-OAM information transfer tools, we report the first observation of the Hong-Ou-Mandel coalescence of two incoming photons having nonzero OAM into the same outgoing mode of a beam-splitter. The coalescence can be switched on and off by varying the input OAM state of the photons. Such effect has been then exploited to carry out the 1 \rightarrow 2 universal optimal quantum cloning of OAM-encoded qubits, using the symmetrization technique already developed for polarization. These results are finally shown to be scalable to quantum spaces of arbitrary dimension, even combining different degrees of freedom of the photons.Comment: 5 pages, 3 figure

Bipolar versus unipolar energy in the surgical ablation of atrial fibrillation in patients with mitral valve surgery

Objective: To evaluate the presence of sinus rhythm or atrial fibrillation (AF) in patients who had mitral valve surgery with concomitant surgical ablation of AF, by unipolar or bipolar radiofrequency. Methods: Adults patients who had mitral valve replacement or mitral valvuloplasty with concomitant surgical ablation of AF, either by unipolar or bipolar radiofrequency, were consecutively included between the 2008 and 2012. Surgery was done by conventional median sternotomy. Results: A total of 99 patients were included; 20 (20.2%) had surgical ablation by unipolar energy and 79 (79.8%) by bipolar energy. There were 76 (76.8%) women, and mean age± SD was 51 ±11 years.  The median duration of AF before surgery was 41 months. Type of AF was paroxysmal in 21 (21%), persistent in 11 (11%), and long-standing persistent in 67 (67%). Mean left atrium size in the preoperative period was 5.54 ± 0.82 cm. Mean left ventricular ejection fraction was 58±12.4%. Types of mitral valve surgery were valvuloplasty (n=10), mechanical valve replacement in 30, and bioprosthesis replacement in 59. Concomitant tricuspid annuloplasty was performed in 39 patients. Thirty- day mortality was 8/99 (8%). Mean follow-up time was 1274 days (3.49 years). Survival was 92%. After 4 years no patient who had had unipolar ablation was in sinus rhythm, whilst 67% of those who had bipolar energy ablation were in sinus rhythm (p<0.001). Conclusion: The use of bipolar energy is superior to unipolar energy in the surgical ablation of atrial fibrillation in patients submitted to mitral valve surgery

Características físicas, químicas e sensoriais de doce de manga cremoso acrescido de farinha de okara

Este trabalho objetivou elaborar e caracterizar doce de manga cremoso acrescido de farinha de okara. Foram elaboradas três formulações: controle (sem adição de farinha), contendo 1% e 3% de farinha de okara. Foram realizadas análises de proteína bruta, extrato etéreo e fibra bruta, na farinha de okara, e pH, acidez, Sólidos Solúveis Totais (SST), proteína, gordura, Atividade de Água (Aw), cor, contagem de bolores e leveduras e análise sensorial, nas formulações de doces. Para os doces elaborados a acidez, Aw e cor (L*, a* e b*) não diferiram entre as amostras. A amostra contendo 3% de farinha obteve os maiores valores de pH, SST, proteína e gordura após a fabricação e após 70 dias de armazenamento. Todas as amostras estavam de acordo com a legislação brasileira para bolores e leveduras. Na análise sensorial, o atributo cor não diferiu entre as amostras controle e as contendo 1% e 3% de farinha. Para aroma, textura, sabor, impressão global e intenção de compra as amostras controle e adicionada de 1% não diferiram entre si, e apresentaram médias superiores à amostra contendo 3% de okara. Os produtos elaborados obtiveram alto valor nutricional e boa aceitação