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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.
111

Composition dynamique de services : application à la conception et au développement de systèmes d'information dans un environnement distribué / Dynamic composition of services : application to designing and developping information systems in a distributed environment

Abi Lahoud, Elie 11 February 2010 (has links)
L'orientation service occupe de plus en plus une place importante dans la structuration des systèmes complexes. La conception et le développement d'applications évoluent progressivement d'un modèle traditionnel vers un modèle plus dynamique orienté services où la réutilisation et l'adaptabilité jouent un rôle important. Dans cette thèse, nous proposons une étude portant sur la conception et le développement d'applications par composition de services. Nous décrivons un environnement de partage de services : DyCoSe. Il consiste en un écosystème coopératif où les entreprises membres, organisées en communautés, partagent un consensus global représentant les fonctionnalités métier récurrentes et les propriétés non fonctionnelles communes. La composition d'applications dans DyCoSe repose sur une architecture à trois niveaux combinant à la fois une démarche descendante et une autre ascendante. La démarche descendante permet de décrire l’application à travers une interaction de composants haut niveau et de la raffiner en une ou plusieurs orchestrations de services. La démarche ascendante projette les caractéristiques de l’infrastructure réseau sous-jacente au niveau services. Un processus d’instanciation visant à réaliser une application composite est détaillé. Il formalise le choix des services, selon un ensemble de contraintes données, comme un problème d’optimisation de coûts. Deux solutions au problème d’instanciation sont étudiées. Une solution globale tient compte de l’ensemble des services disponibles dans l’écosystème et une solution locale favorise les services de certaines communautés. Un algorithme génétique est décrit comme implémentation de l’instanciation globale. Une simulation stochastique de l’environnement DyCoSe est proposée. Elle permet d'étudier les possibilités d’instanciation d’une application donnée dans un environnement où la disponibilité des services n’est pas garantie. Elle permet d'étudier aussi, le taux de réussite de l’exécution d’une instance d’une application donnée. / The service oriented computing paradigm plays an increasingly important role in structuring complex systems. Application design and development approaches are witnessing a shift from traditional models towards a more dynamic service oriented model promoting reuse and adaptability. In this thesis, we study an approach for application design and development based on services’ composition. We propose DyCoSe, an environment for sharing services. It consists of an enterprise ecosystem wherein members, organized in communities, share a global agreement describing traditional business functionalities and common non-functional properties. DyCoSe relies on a three level architecture for service based application composition combining both, a top down and a bottom up composition approach. The top down part describes an application using high-level components and refines it to an orchestration of services. The bottom up part projects network characteristics to the services’ level. An instantiation process aiming at realizing an application is described. It formalizes services’ selection as a cost optimization problem considering a set of user given constraints. Two solutions of the instantiation problem are proposed. A global solution considers all the available services in an ecosystem. A local solution gives priority to services of selected communities. A genetic algorithm implements the global instantiation. A stochastic simulation of DyCoSe is proposed. It allows studying the instantiation success rate and the application execution success rate both in a dynamic environment wherein services availability is not guaranteed.
112

Effet de traitements thermiques sur les propriétés fonctionnelles de fromages traditionnels : le cas des pâtes persillées / Effect of some heat treatments on some functional properties of traditional cheeses : the case of blue cheeses

Abbas, Khaled 13 January 2012 (has links)
Les ventes des fromages AOP subissent un affaiblissement. L’utilisation de ces fromages sous forme d’ingrédient représente une alternative intéressante à la dégustation et permettrait de maintenir une activité durable aux producteurs de ces fromages. L’objectif de ce travail est d’explorer les potentialités de 4 catégories de fromages à pâte persillée AOP du Massif-Central à être utilisés comme ingrédient à chaud pour répondre à des propriétés telles que « fondant, nappant, filant, gratinant». Les fonctionnalités recherchées pour ce type d’usage ont été prospectées à l’aide de méthodes physico-chimiques et instrumentales classiques mais également à l’aide de méthodes spectrales et sensorielles afin d’enrichir les observations de la macro et microstructure fromagère et de la perception du consommateur. Dans un premier temps, les caractéristiques physicochimiques, rhéologiques et sensorielles à froid et certaines propriétés à chaud ont été décrites pour les 4 catégories de fromages. Ces premiers résultats ont permis de cataloguer les fromages selon des caractéristiques essentiellement liées à l’organisation matricielle des composants tels que les protéines, les matières grasses, les minéraux. L’analyse sensorielle a permis de décrire précisément certaines propriétés à froid qui ne sont pas mises en évidence par d’autres analyses. Les pâtes persillées ont une grande hétérogénéité de pâte due à la présence de« veines » de moisissures. La seconde partie est une étude sur la capacité de la SFS en tant que méthode d’étude de la micro structure, à prédire la diversité de composition de ces fromages. Malgré la forte hétérogénéité des fromages, la SFS permet une « empreinte » identifiable des fromages et prédit certains mais pas la totalité des paramètres physicochimiques. L’évolution de la macro et microstructure de ces fromages au cours du chauffage et du refroidissement a ensuite été étudiée par SFS et par test de compression dynamique. Ces méthodes décrivent bien la fonte de la matière grasse et de la matrice fromagère. Elles sont corrélées entre elles et démontrent une relation entre la structure moléculaire et les propriétés rhéologiques de ces fromages. Une étude comparative des propriétés sensorielles des fromages a été menée à froid et après chauffage. Les attributs décrivent des caractéristiques de texture différentes entre les 2 conditions. Cette démarche a permis de bien différencier les 4 catégories de fromages et de mettre en évidence certains attributs de qualité ou de défaut pour une utilisation à chaud. En conclusion, ces 4 catégories de fromages à pâte persillée ont des potentialités à être utilisées comme ingrédient pour usage à chaud. L’analyse sensorielle a caractérisé les perceptions des consommateurs vis à vis de ces fromages chauffés et ainsi aider à préciser leurs fonctionnalités. Les analyses rhéologiques et spectrales ont apporté des explications liées à ce traitement au niveau de la macro et microstructure de la matrice fromagère. / Sales of PDO cheeses undergo a decline. The use of these cheeses in the form of ingredient represents an interesting alternative to the tasting and would allow to maintain a sustainable business activity to the producers of these cheeses. The objective of this work is to investigate the potentialities of four categories of Blue cheese PDO of the Massif Central as an ingredient to meet their properties during heating such as "melting, stretchability, browning". The functional properties desired for this type of cheese have been investigated by physico-chemical methods and instrumental classics and also by spectral method and sensory evaluations to enrich the observations of the macro and microstructure of the cheese and the consumer perception. First, the physicochemical, rheological, sensory characteristics and certain properties during heating have been reported for four categories of Blue cheese. These initial results allowed us to characterize the cheese studied according to their characteristics essentially which were related to the organization matrix constitutes such as proteins, fats, minerals. The sensory analysis allowed to describe exactly certain properties which are not revealed by theother analyses. Blue-veined cheeses have a great heterogeneity due to the presence of "veins" of mold. The second part is a study on the ability of the SFS method to study the micro structure and to predict the diversity of composition of these cheeses. Despite the high heterogeneity of cheeses, SFS allows an identifiable 'fingerprint' of cheese and predicts some but not the totality of the physicochemical parameters. The evolution of the macro-and microstructure of these cheeses during heating and cooling was then studied by SFS and dynamic shear test. These methods describe well the melting temperature of the fat and the cheese matrix. They are correlated between them and demonstrate a relationship between the molecular structure and the rheological properties of these cheeses. A comparative study of the sensory textural properties of cheeses was carried out in the non- and heated forms. The attributes describe different characteristics of texture between the two conditions. This approach allowed to differentiate well the four categories of cheeses and to highlight on certain attributes of quality or defects to be used in cooking application. In conclusion, these four categories of Blue-veined cheeses have the potential to be used as an ingredient in cooking application. The sensory analysis characterized the perceptions of the consumers in both non- and heated forms and thus helps to specify their features. The rheological and spectral analyses have provided explanations related to this treatment at the level of the macro and microstructure of the cheese matrix.
113

Efeito das variações térmicas na perda de umidade em carcaças de frango / Effect of thermal variation on the moisture loss in broiler carcasses

Fábio de Oliveira Franco 24 August 2007 (has links)
O presente trabalho objetivou estudar o impacto das variações térmicas durante o armazenamento de carcaças de frango sobre as propriedades funcionais, especialmente a perda de umidade no descongelamento (Drip Loss). Para avaliação destas condições, foram simuladas duas situações: uma comercial, onde um lote de aves abatidas, evisceradas e resfriadas em chiller foram congeladas até -15 (±2)°C e sofreram variações térmicas em ciclos de 8 horas com retirada das mesmas da câmara de estocagem, passando de -15 (±2)°C a -3(±2)°C, momento em que eram novamente devolvidas a câmara de congelamento (situação crítica) e outro lote mantido congelado a -15(±2)°C (situação ideal). Outra condição, chamada de ensaio modelo, foram simuladas 7 faixas de temperatura de armazenamento (0°C, -3°C, -6°C, -9°C, -12°C, -15°C e -18°C) visando definir faixas críticas, baseadas em valores de Drip Loss. Foram definidas 2 faixas: -3°C e -6°C, baseadas em sua proximidade a faixa mais crítica e com valores maiores de Drip Loss (0°C). Para estudo das propriedades funcionais no ensaio comercial, amostra (n=120) de carcaças, divididas em situação ideal (n=60) e situação crítica (n=60) foram descongeladas e submetidas às análises de pH, cor e perda de umidade por descongelamento (Drip Test). Os resultados encontrados mostraram uma tendência (p<0,05) de aumento do Drip Loss com o aumento do tempo de armazenamento na situação crítica, com valores de 4,77(±1,24)% para 3 dias e 10,28(±0,87)% para 120 dias. A situação ideal não apresentou diferenças significativas entre os resultados encontrados, que foram de 5,19(±1,13)% para 3 dias e 4,86(±0,84)% para 120 dias. Para estudo das propriedades funcionais no ensaio modelo, amostras (n=70), em triplicata, de carcaças foram descongeladas e, após a definição das faixas críticas, submetidas às análises de perda umidade por descongelamento (Drip Test), capacidade de retenção de água, análise de perda de umidade no cozimento, quantificação do gel protéico, análise do teor de proteínas no exsudato, análise do perfil protéico do exsudato e análise histológica. Os resultados demonstraram não haver diferenças estatísticas (p<0,05) entre as faixas críticas estudadas (-3°C e -6°C) em relação às propriedades funcionais, com exceção das análises de perda de umidade por descongelamento (Drip Test), onde a mesma tendência de aumento do Drip Loss em relação ao tempo de armazenamento foi encontrada, com valores de 5,85 (±1,16)% para 0 dia e 12,33 (±1,12)% para 70 dias na faixa -3°C e 5,83 (±1,93)% para 0 dia e 10,15 (±0,15)% para 70 dias na faixa -6°C. Concluindo, existem evidências de que as variações térmicas promovem o aumento do Drip Loss em relação a um maior tempo de armazenamento. A constatação deste fato serve como base para estudos mais aprofundados sobre o impacto das condições de armazenamento sobre as propriedades funcionais da carne de frango, bem como para padronizar os processos de congelamento, transporte, distribuição e venda de carne de frango congelada. / The objective of this work was to study the impact of thermal variations during the storage of broiler carcasses on its functional properties, especially the moisture loss during thawing (Drip Loss). In order to evaluate these conditions, two situations were simulated: one called commercial, where a batch of slaughtered, eviscerated and chilled on water system broilers were frozen to -15(±2)°C and divided in two equal batches: one of these batches was called Critical Condition and was maintained in a 8 hour cycle of thermal variation ranging from -15(±2)°C to -3(±2)°C while the other, called Ideal Condition was maintained at -15(±2)°C during all the storage time. In another situation, named Model, seven ranges of storage temperature (0±2°C, -3±2°C, -6±2°C, -9±2°C, -12±2°C, -15±2°C , -18±2°C) were simulated in order to obtain the critical ranges based on the Drip Loss values. Two ranges were found based on its proximity to the most critical range and bigger Drip Loss values: -3±2°C and -6±2°C. For the functional properties studies on the commercial situation, a sample (n=120) of broiler carcasses, equally divided in Critical and Ideal were unfrozen and pH, color and Drip Loss analyzed. The results showed a statistical trend (p<0,05) of increase of Drip Loss values as time of storage increases in the critical condition, with values of 4,77±1,24% for 3 days of storage and 10,28±0,87% for 120 days of storage. The ideal condition didnt showed significant differences among the obtained results that were from 5,19±1,13% for 3 days of storage to 4,86±0,84% for 120 days. For the functional properties studies on the model situation, a sample (n=70), in triplicate, of broiler carcasses was thawed and, after the definition of the critical ranges, it was analyzed for Drip Loss, water holding capacity, moisture loss during cooking, Exudative cooking gel quantification, protein quantification on the exsudate, protein profile on the exudate and histological evaluation. The results showed that there were no statistical differences (p<0,05) between the studied critical ranges (-3±2°C and -6±2°C) in relation to its functional properties, except for Drip Loss values, where a trend of increase in Drip Loss as the time of storage increases was found, with values from 5,85±1,16% for 0 days to 12,33±1,12% for 70 days in range -3±2°C and from 5,83±1,93% for 0 days to 10,15±0,15% for 70 days in range -6±2°C. In conclusion, theres some evidence that the thermal variation can cause the increase of Drip Loss values in relation to an increase of the storage time. All these data can be useful as basis for new studies on functional properties of broiler meat regard to thermal variation during storage, as well as, to standard the processes of freezing, transport, distribution, and retail of frozen broiler meat.
114

Funkcionalni proizvodi na bazi cerealija i pseudocerealija sa dodatkom inkapsuliranog ekstrakta tropa cvekle / Cereal- and pseudocereal-based functional products with encapsulated beetroot extract

Jakišić Mirjana 23 December 2020 (has links)
<p>U okviru disertacije kreirani su novi, nutritivno obogaćeni, fini pekarski proizvodi na bazi bra&scaron;na od cerealija i pseudocerealija, kroz čiju se proizvodnju valorizuju sporedni proizvodi prehrambene industrije &ndash; trop cvekle. Rezultati istraživanja pružaju nova saznanja o stepenu redukcije bioaktivnih jedinjenja (polifenola i betalaina) tokom postupka proizvodnje i skladi&scaron;tenja finih pekarskih proizvoda obogaćenih ekstraktom tropa cvekle, kao i njihov uticaj na reakcije neenzimskog tamnjenja.<br />Uspe&scaron;no realizovana istraživanja ukazala su na stepen stabilinosti bioaktivnih jedinjenja iz tropa cvekle inkapsulacijom na protein soje i na opravdanost primene ove metode (tehnike) u proizvodnji funkcionalne hrane. Na ovaj način se obezbeđuju funkcionalni proizvodi koji sadrže dovoljnu količinu visokovrednih jedinjenja koja imaju veću bioraspoloživost i finalan zdravstveni efekat. Zbog niza prednosti inkapsulirane forme ekstrakta imaju veliki potencijal primene u industriji u vidu boja i aditiva, tj. funkcionalnih dodatakau prehrembenim ali i kozmetičkim proizvodima. Istraživanja u okviru disertacije omogućavaju dobijanje inovativnih proizvoda koji pro&scaron;iruju asortiman nutritivno vrednih proizvoda i doprinose kvalitetnijoj ishrani potro&scaron;ača.<br />Upotrebom nusproizvoda prerade voća i povrća smanjuje se količina otpada i doprinosi za&scaron;titi životne sredine, povećava dobit proizvođača kroz pobolj&scaron;anje iskori&scaron;ćenja sirovine i konkurentnosti na trži&scaron;tu.</p> / <p>Within the thesis a new, nutrient-rich, fine bakery products based on flour of cereals and pseudocereals were created, through the production of which valorizing by-products of the food industry are produced- pomace beetroot. Results of the research provide new knowledge about degree of reduction bioactive compounds (polyphenols and betalains) during process of production and storage of fine bakery products enriched with beetroot pomace extracts, as well as their influence on non-enzymatic tanning reactions.<br />Successfully realized researches have indicated degree of stability bioactive compounds from beetroot pomace by encapsulation on soy protein and justification of application this method (technique) in the production of functional food. In this way, functional products witch contain a sufficient amount of high-value compounds which have higher bioavailability and final health effect are provided. Due to a number of advantages, encapsulated form of the extract have a great potential for application in industry like food color and additives, ie. functional supplements for food and cosmetic products. Research in the framework of the thesis allow obtaining innovative products which expand the range of nutritionally valuable products and contribute to the quality consumers diet.<br />Using by-products of processing fruits and vegetables reduces the amount of waste and contributes to the protection of environment, increases the profit of producers by improving the efficiency of raw materials and market competitiveness.</p>
115

Knowledge of chronic complications amongst diabetic patients in the Vhembe District of Limpopo Province, South Africa

Motsharine, Selina 18 May 2018 (has links)
MCur / Department of Advanced Nursing Science / Diabetes mellitus is a global health issue affecting people of all ages. It is defined as a non-communicable chronic disease caused by abnormal insulin production, impaired insulin utilization or both. Its prevalence and complications is increasing rapidly. The aim of this study was to assess knowledge of Diabetes mellitus chronic complications among diabetic patients in the Vhembe district of the Limpopo Province, South Africa. The study objectives were: to assess the knowledge of Diabetes mellitus chronic complications amongst diabetic patients; to determine the knowledge of diabetic patients regarding self-care practice, control and management of diabetes in the Vhembe District, and to identify challenges faced by diabetic patients regarding chronic complications of Diabetes mellitus in the Vhembe District A quantitative descriptive design was used. The study population was diabetic patients who were visiting the selected 4 hospitals, 2 health centers and 2 clinics were in Thulamela Municipality. Convenient sampling was used to sample 259 respondents (184(71%) females and 75(29%) males) and to select the 8 health care services. A structured, closed-ended selfadministered questionnaire in Tshivenda was used to collect data on the day that diabetic patients were coming for follow-up treatment, and after they had been attended to by the health care providers. Data were analyzed using the / NRF
116

Validation of theoretical cost model for Power and Reliability : Case study of a reliable Central Direct Memory Access system / Validering av teoretisk kostnadsmodell för Power and Reliability : Fallstudie av ett tillförlitligt Central Direct Memory Access-system

Shrivastava, Sonal January 2021 (has links)
Safety-critical applications employed in automotive, avionics and aerospace domains are placed under strict demands for performance, power efficiency and fault tolerance. Development of system hardware and software satisfying all criteria is challenging and time-consuming. System co-design based on specifications and desired high-performance requirements, is one solution to this problem, however, it remains a largely unexplored territory. Currently at KTH Royal Institute of Technology, a co-design framework in relation to theoretical system design models is being researched with the objective to move the embedded system design to a higher abstraction level. Presently, it focuses on correct-by-construction design of low power and reliable safety-critical systems. This thesis intends to assess the accuracy of this framework in comparison to conventional design approaches. The accuracy is evaluated empirically in terms of extra functional requirements - average total power consumption and Mean Time Between Failure (MTBF). A simple payload Central Direct Memory Access (CDMA) application is integrated with Xilinx Soft Error Mitigation (SEM) IP Core and source of system failure is a Single Event Upset (SEU) which occurs due to ionizing radiations. Measurements obtained from this reference system are compared to results determined theoretically from model related equations for the same system. Comparison of measured MTBF values with theoretical estimations shows that measured ones are higher by an average huge difference of 324.63%. Similarly for power consumption, measurements were found to be higher than estimated ones by 0.4465 Watts. In conclusion, it can be said that theoretical model design framework is not accurate and models must somehow take into account implementation dependent factors. Nevertheless, this case study provided a good insight and pathways for enhancements and optimizations to turn this reference into a dependable platform. Finally, future work required for desirable experiment system improvements are identified. / Säkerhetskritiska applikationer som används inom fordons-, flyg- och flygindustrin ställs strikta krav på prestanda, energieffektivitet och feltolerans. Utveckling av systemhårdvara och mjukvara som uppfyller alla kriterier är utmanande och tidskrävande. Systemdesign baserad på specifikationer och önskade högpresterande krav är en lösning på detta problem, men det är fortfarande ett i stort sett outforskat område. För närvarande vid KTH Royal Institute of Technology undersöks ett ramverk för samdesign i relation till teoretiska systemdesignmodeller undersöks med målet att flytta den inbyggda systemdesignen till en högre abstraktionsnivå. Nuvarande, den fokuserar på korrekt konstruktion av låg effekt och pålitliga säkerhetskritiska system. Denna avhandling avser att bedöma riktigheten i detta ramverk i jämförelse med konventionella designmetoder. Noggrannheten utvärderas empiriskt när det gäller extra funktionskrav - genomsnittlig total strömförbrukning och medeltid mellan misslyckande (MTBF). En enkel nyttolast central direktminnesåtkomst (CDMA) applikation är integrerad med Xilinx begränsning av en händelse (SEM) IP kärnan och källan till systemfel är en singelhändelse upprörd (SEU) som uppstår på grund av joniserande strålning. Mätningar erhållna från detta referenssystem jämförs med resultat som bestämts teoretiskt från modellrelaterade ekvationer för samma system. Jämförelse av uppmätta MTBF -värden med teoretiska uppskattningar visar att uppmätta värden är högre med en genomsnittlig enorm skillnad på 324,63%. På samma sätt för strömförbrukning befanns mätningarna vara högre än beräknade med 0,4465 Watt. Sammanfattningsvis kan man säga att det teoretiska ramverket för modelldesign inte är korrekt och att modellerna på något sätt måste ta hänsyn till implementeringsberoende faktorer. Ändå gav denna fallstudie en bra insikt och vägar för förbättringar och optimeringar för att göra denna referens till en pålitlig plattform. Slutligen identifieras framtida arbete som krävs för önskvärda experimentsystemförbättringar.
117

The milk fat globule membrane: physico-chemical studies and its techno-functional valorisation in buttermilk

Vanderghem, Caroline 04 June 2009 (has links)
Vanderghem Caroline. (2009). La membrane du globule gras du lait : études physico-chimiques et sa valorisation technofonctionnelle dans les babeurres (Thèse de doctorat en Anglais). Gembloux, Belgique, Faculté Universitaire des Sciences Agronomiques de Gembloux. 198p., 14 tabl., 59 fig. Résumé La membrane du globule gras du lait (MGGL) est une structure complexe qui enveloppe, protège et délivre des composants bioactifs et des nutriments dune façon efficace au nouveau-né. Sa structure est unique par rapport à dautres systèmes biologiques de transport de lipides. Lobjectif général de ce travail a été de contribuer à augmenter les connaissances et la compréhension de cet émulsifiant naturel. La première partie de cette thèse concerne létude de la structure de la MGGL. Limportance des protéines membranaires concernant la stabilité et leur disposition dans la MGGL ont été étudiés. Les protéines de la MGGL sont présentes en petite quantité dans le lait et une technique de pré-fractionnement simpose afin de les isoler par rapport aux autres protéines du lait (caséines et protéines du lactosérum). Une technique dextraction qui a été développée dans notre laboratoire a été testée afin disoler la MGGL de la crème laitière. Une analyse détaillée a révélé que cette procédure est très bien adaptée pour lélimination dun maximum de protéines du lait écrémé. Une approche protéomique a été établie et a permis lidentification de protéines majeures de la MFGM ainsi que dautres protéines mineures (GTP-binding proteins, annexins, actin) afin de compléter le protéome. Par la suite, différentes protéases ont été testées en vue dobtenir différents degrés et/ou sélectivité dhydrolyse des protéines de la MGGL. La distribution asymétrique des protéines de la MGGL a été étudiée par une approche basée sur lattaque protéolytique du globule gras natif. Sur base de nos résultats et des données bibliographiques récentes, un nouveau modèle de la structure de la MGGL est proposé. La deuxième partie de cette thèse est consacrée à évaluer les propriétés technofonctionnelles de la MGGL dans les babeurres. Les propriétés interfaciales, moussantes et émulsifiantes du babeurre sont comparées à dautres ingrédients laitiers comme le lait écrémé et le concentré protéique de lactosérum. Nos résultats montrent le bon pouvoir émulsifiant du babeurre en comparaison des autres ingrédients laitiers. Dans les émulsions recombinées, la stabilité envers le crémage a été améliorée et les membranes ont présenté une meilleure résistance face à la coalescence. Les résultats sur la tension interfaciale et les propriétés rhéologiques interfaciales ont été mis en relation avec certaines propriétés des mousses et des émulsions. Vanderghem Caroline. (2009). The milk fat globule membrane: physico-chemical studies and its techno-functional valorisation in buttermilk (Thèse de doctorat). Gembloux, Belgium, Gembloux Agricultural University, 198p., 14 tabl., 59 fig. Summary The milk fat globule membrane (MFGM) is a complex structure that surrounds, protects and delivers bioactive compounds and nutrients in an efficient manner to the neonate. Its structure is unique in relation with any other biological lipid transport system. The overall aim of this work was to contribute to increase the knowledge and comprehension of this natural emulsifier. The first part of this thesis concerned the study of the structure of the MFGM. Membrane proteins were targeted and their importance regarding stability and disposition in the MFGM was studied. MFGM proteins are present at low concentrations in milk and a pre-fractionation of the sample is required in order of MFGM proteins to be visible among other milk proteins (caseins and whey proteins). A mild procedure developed in our laboratory was tested in order to isolate MFGM from cream. Detailed analysis revealed that this procedure is very well suited for the elimination of a maximum of skim milk proteins. A proteomic approach was established and allowed the identification of the most important MFGM proteins and additional minor MFGM proteins for additional completion of the proteome (GTP-binding proteins, annexins, actin). Subsequently, different proteases were screened in an attempt to obtain different degrees and/or selective proteolysis of MFGM proteins. Asymmetric arrangement of MFGM proteins was studied with an approach based on the proteolytic attack on the native fat globule. Based on our results and recent bibliographic data, an updated model of the MFGM structure was proposed. The second part of this thesis was devoted to assess the techno-functional properties of the MFGM in buttermilks. Interfacial, foaming and emulsifying properties of buttermilk were assessed and compared to classic milk ingredients such as skim milk and whey protein concentrate. Our results highlighted that buttermilk possesses good emulsifying power compared to other milk ingredients. In buttermilk recombined emulsions stability towards creaming was improved and the recombined membrane presented a great resistance to coalescence. Results of the interfacial pressure and the interfacial rheological properties were related to some foams and emulsions properties.
118

Advances in animal blood processing: development of a biopreservation system and insights on the functional properties of plasma

Dàvila Ribot, Eduard 09 February 2007 (has links)
La sang és un subproducte amb un alt potencial de valorització que s'obté en quantitats importants en els escorxadors industrials. Actualment, la majoria de sistemes de recollida de la sang no segueixen unes mesures d'higiene estrictes, pel que esdevé un producte de baixa qualitat microbiològica. Conseqüentment, l'aprofitament de la sang és una sortida poc estimulant des del punt de vista econòmic, ja que acostuma a perdre les qualitats que permetrien l'obtenció de productes d'alt valor afegit. El capítol I del present treball s'inclou dins d'un projecte que proposa la inoculació de bacteris de l'àcid làctic (LAB) com un cultiu bioconservador de la sang, un sistema senzill i de baix cost que cerca l'estabilitat de la sang, tant microbiològica com fisicoquímica, durant el període del seu emmagatzematge. El capítol II s'emmarca dins d'un projecte que cerca la millora de l'aprofitament integral de la sang que, en el cas de la fracció plasmàtica, es centra en l'estudi de la funcionalitat dels seus principals constituents. Conèixer la contribució dels components majoritaris ha de permetre la millora de la funcionalitat dels ingredients alimentaris derivats. Els resultats presentats en aquesta tesi poden ajudar a la valorització de la sang porcina d'escorxadors industrials, mitjançant els coneixements adquirits pel que fa a la millora del seu sistema de recollida i del desenvolupament d'ingredients alimentaris amb interessants propietats funcionals. / Blood is a by-product obtained in large amounts in industrial slaughterhouses with a high potential of valorisation. Currently, most of the blood collecting systems are not subjected to strict hygienic measures hence it becomes a product with low microbiological quality. As a result, the use of blood for consumption purposes is not a stimulating prospect from an economic point of view, because the intrinsic worth allowing the development of high value-added products is normally lost.Chapter I of the present dissertation is included within a research project that suggests lactic acid bacteria (LAB) as a blood biopreservative culture: a simple, inexpensive system to keep the stability of blood both in terms of microbiological and physicochemical quality, during its storage.Chapter II is framed within a research project that investigates ways to improve the use of blood as a food ingredient, which, in the case of plasma, is focused on the functionality of its main protein constituents. The knowledge of the contribution of each constituent can be used to improve the functional properties of plasma-based ingredients. The results presented in this thesis dissertation may help the valorisation of porcine blood from industrial slaughterhouses, thanks to the acquired knowledge about the improvement of blood preservation and the development of plasma-based food ingredients with interesting functional properties.
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Deciphering Structure-Function Relationships in a Two-Subunit-Type GMP Synthetase by Solution NMR Spectroscopy

Ali, Rustam January 2013 (has links) (PDF)
The guanosine monophosphate synthetase (GMPS) is a class I glutamine amidotransferase, involved in the de-novo purine nucleotide biosynthesis. The enzyme catalyzes the biochemical transformation of xantosine (XMP) into guanosine monophosphate (GMP) in presence of ATP, Mg2+ and glutamine. All GMPSs consist of two catalytic sites 1) for GATase activity 2) for the ATPPase activity. The two catalytic sites may be housed in the same polypeptide (two-domain-type) or in separate polypeptides (two-subunit-type). Most of the studies have been performed on two-domain-type GMPSs, while only one study has been reported from two-subunit-type GMPS (Maruoka et al. 2009). The two-subunit-type GMPS presents an example where the component reactions of a single enzymatic reaction are carried out by two distinct subunits. In order to get better understanding of structural aspects and mechanistic principle that governs the GMPS activity in two-subunit-type GMPSs, we initiated the study by taking GMPS of Methanocaldococcus jannaschii as a model system. The GMPS of M. jannaschii (Mj) is a two-subunit-type protein. The GATase subunit catalyzes the hydrolysis of glutamine to produce glutamate and ammonia. The ATPPase subunit catalyses the amination of XMP to produce GMP using the ammonia generated in GATase subunit. Since the two component reactions are catalysed by two separate subunits and are coupled in the way that product of one reaction (ammonia) acts as a nucleophile in the second reaction. The cross-talk between these two subunits in order to maximise the efficiency of overall GMPS warrants investigation. The GATase activity is tightly regulated by the interaction with ATPPase domain/subunit, in all GMPS except in the case of P. falciparum. This interaction is facilitated by substrate binding to the ATPPase domain/subunit. Though, the conditions for the interaction between two subunits is known in a two-subunit-type GMP synthetase from P. horikoshii, the structural basis of substrate dependent interaction is not known. As a first step to understand the structural basis of interaction between the Mj GATase and Mj ATPPase subunits, we have determined the structure of Mj GATase (21 kDa) subunit using high resolution, multinuclear, multidimensional NMR spectroscopy. Sequence specific resonance assignments were obtained through analysis of various 2D and 3D hetero-nuclear multidimensional NMR experiments. NMR based distance restraints were obtained from assignment of correlations observed in NOE based experiments. Data were acquired on isotopically enriched samples of Mj GATase. The structure of Mj GATase (2lxn) was solved by using cyana-3.0 using NMR based restraints as input for the structure calculation. The ensemble of 20 lowest-energy structures showed root-mean-square deviations of 0.35±0.06 Å for backbone atoms and 0.8±0.06 Å for all heavy atoms. Attempts were also made to obtain assignments for the 69.6 kDa dimeric ATPPase subunit. Partial assignments have been obtained for this subunit. The GATase subunit is catalytically inactive. So far, there has been only one published report on a two-subunit-type GMPS from P. horikashii. The study has shown that the catalytic activity of GATase is regulated by the GATase-ATPPase interaction which is facilitated by the substrate binding to the ATPPase subunit. For the first time, we have provided the structural basis of interaction between GATase-ATPPase (112 kDa) in a two-subunit-type GMPS. Observed line width changes were used to identify residues in GATase residues that are involved in the Mj GATase-ATPPase interaction. Our data provides a possible explanation for conformational changes observed in the Mj GATase subunit upon GATase-ATPPase interaction that lead to GATase activation. Ammonia is generated in GATase subunit and is very reactive and labile. Thus, the faithful transportation of ammonia from GATase to ATPPase subunit is very crucial for optimal GMPS activity. Till date, a PDB query for GMPS retrieves only one structure which belongs to two-subunit-type GMPS, where authors have determined the structures of GATase and ATPPase subunits separately. However, the structure of holo-GMPS is not determined yet. Using interface information from experimental data and HADDOCK, we have constructed a model for the holo-GMPS from M. jannaschii. A possible ammonia channel has been deduced using the programs MOLE 2.0 and CAVER 2.0. This ammonia channel has a length of 46 Å, which is well within the range of the lengths calculated for similar channels in other glutamine amidotransferase. It had been suggested earlier that in addition to the magnesium required for charge stabilization of ATP, additional binding sites were present on GMPS. The effect of excess Mg2+ requirement on the GMPS activity has been studied in two-domain-type GMPS. However, the interaction between GATase and Mg2+ has been not investigated in any GMPS. This prompted us to investigate the effect of MgCl2 on Mj GATase subunit. For the first time, using chemical shift perturbation, we have established interaction between Mj GATase and Mg2+. The dissociation constant (Kd) of the Mj GATase-Mg2+ interaction was determined. The Kd value was found to be 1 mM, which indicates a very weak interaction. The substrate of the GATase subunit is glutamine. The condition of the hydrolysis of the glutamine is known in GMPS. However, the binding of the glutamine and associated conformational changes in GATase have been not studied in GMPS. Furthermore, till date there is no structure available for the glutamine bound GMPS/GATase. Using isotope edited one dimensional and two-dimensional NMR spectroscopy; we have shown that the Mj GATase catalytic residues are not in a compatible conformation to bind with glutamine. Thus, a conformational change in Mj GATase subunit is a pre-requisite condition for the binding of glutamine. These conformational changes are brought by the Mj GATase-ATPPase interaction.
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Methodische Aspekte bei der Entwicklung mechanischer Simulationen zur Messung der Funktionalitäten eines Handballschuhs

Krumm, Dominik 17 March 2020 (has links)
Ziel der vorliegenden Arbeit war es, die methodischen Aspekte bei der Entwicklung mechanischer Simulationen zur Messung der Funktionalitäten von Handballschuhen systematisch zu untersuchen und aus den Ergebnissen allgemeingültige Aussagen zum Abstraktionsgrad abzuleiten. Die Untersuchungen der vier methodischen Aspekte Messgerät, Auswertemodell, Einfluss- und Eingangsgröße haben ergeben, dass insgesamt drei Aspekte einen Einfluss auf den Messwert hatten. Mit Ausnahme der Ergebnisse zum Aspekt Eingangsgröße besaßen die untersuchten methodischen Aspekte jeweils einen Einfluss auf den Messwert. Anhand der Ergebnisse konnte abgeleitet werden, dass der Abstraktionsgrad einen Einfluss auf die Messwerte besitzt. / The aim of the current work was to investigate systematically the methodological aspects used in the development of mechanical simulations, which are capable of measuring the functionalities of handball shoes, and to derive general conclusions about the proper degree of abstraction from the results. The investigations of the four methodological aspects, namely measuring instrument, evaluation model, influence quantity and input quantity, have shown that three aspects had an influence on the measurand. Except for the results on the aspect of input quantity, each of the examined methodological aspects had an influence on the measurand. Based on the results, it could be deduced that the degree of abstraction has an influence on the measurand.

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