lin-11 and let-711 are early-developmental gene expression regulators with no previously known roles in aging regulation. Yet, they show strong aging-correlated expression profiles (Lund, Tedesco et al. 2002). lin-11 is strongly upregulated in very old worm populations, and let-711 is progressively downregulated in aging worm populations. Microarray studies were performed to identify their genome-wide targets, which were then subjected to further lifespan and genetic analysis to investigate their role in C. elegans aging. The results indicate that the target pools of both lin-11 and let-711 are enriched for aging genes, since a significant number of tested genes increased lifespan. This enrichment of aging genes in their target pools provides strong evidence that lin-11 and let-711 are indeed regulating the expression of aging genes in adult C. elegans. The data suggests that increased lin-11 expression as well as reduced let-711 expression may be promoting longevity by downregulating the insulin/IGF-1 pathway. Decreasing let-711 may also be contributing to longevity by downregulating the germline signaling pathway. K11E4.2, R53.5, C49A9.2 and Y82E9BR.5 are four genes from the lin-11 target pool, whose knockdown produced increases inlifespan. These are unannotated genes, and the details of their roles in aging regulation are not known at this point. ins-3 expression was downregulated two-fold upon knockdown of lin-11, suggesting the possible involvement of lin-11 in regulation of the insulin/IGF-1 pathway. An RNAi construct for ins-3 was not available and it is not known whether loss of ins-3 leads to lifespan extension. let-711 knockdown resulted in an almost four-fold reduction in pdk-1 expression. pdk-1 is an integral part of the insulin/IGF-1 pathway and its knockdown by RNAi extended lifespan. Four other genes from the let-711 target pool that increased lifespan, cdc-25.1, gna-2, meg-1 and ooc-3, all have germline specific functions. The extensions in lifespan generated by these genes were completely dependent on DAF-16. Furthermore, for gna-2, meg-1 or ooc-3, they were independent of DAF-2. These results agree with previously established mechanisms for germline regulation of aging, suggesting the involvement of let-711 in regulating the germline-signaling pathway.

Doktorsavhandling--Department of Economic History--Uppsala, 1994. / Résumé en anglais.

Thesis (M.A.)--University of Hong Kong, 1966. / Also available in print.

Thesis (M.S.)--Ohio State University, 2005. / Includes bibliographical references (leaves 105-110). Available online via OhioLINK's ETD Center

Cette thèse de doctorat a été réalisée dans le cadre du projet Fiabilin, qui regroupe 15 partenaires industriels et académiques, et vise à structurer une filière industrielle de production de biocomposites polyamide-11/fibres de lin. Ces travaux ont pour objectif de déterminer des performances multi-échelles de ce composite 100% biosourcé, afin d’envisager son usage en substitution de composites pétrosourcés. Nous avons tout d’abord mis en évidence la sensibilité des fibres de lin aux cycles temps-température des procédés de mise en œuvre, tant du point de vue de leurs propriétés mécaniques que de leur structure biochimique. Ensuite, nous avons montré les capacités du système PA11-lin à produire des performances mécaniques en traction compétitives vis-à-vis d’autres composites pétrosourcés. La qualité de l’interface fibre/matrice du biocomposite a également été étudiée à différentes échelles, montrant une compatibilité supérieure à celles de systèmes lin-résines thermodurcissables. La fin de vie du composite PA11-lin a été envisagée à travers le recyclage par broyages et injections successives. Les propriétés mécaniques du biocomposite à fibres courtes ainsi obtenu sont semblables au composite PPgMA-lin, avec une déformation à rupture accrue et qui augmente significativement avec le nombre de recyclages. Une analyse des cycles de production de plusieurs composites révèle les plus faibles impacts environnementaux du PA11-lin lors d’un dimensionnement des pièces en rigidité équivalentes. / This thesis has been carried out as part of the project Fiabilin, which includes 15 different academic and industrial partners, with an aim to develop industrial production of polyamide-11/flax biocomposite. The purpose of this work is to determine multi-scale performances of 100% biosourced composite, in order to substitute composite materials containing glass fibers and/or matrix derived from petroleum. First, we highlighted the flax fiber sensibility toward processing cycles (time and temperature), from mechanical and biochemical structure aspects. Then, we revealed the capacity of PA11-flax association to produce competitive mechanical properties compared to others usual composites. Fiber-matrix interface of the biocomposite was studied at micro and macro scales, showing a higher compatibility than some flax-thermoset resin systems. The end-of-life of the biocomposite was considered by recycling with successive grinding and injections. Then stiffness and strength at break of short fiber biocomposites thus obtained are similar to PPgMA-flax composites, whereas a strong increase of the strain at break according to the number of injection cycles was observed. A life cycle analysis of some composites production steps shows lower environmental impacts of PA11-flax when sizing was made through equivalent material stiffness.

Cette thèse a pour objectif de valoriser par une caractérisation multi-échelle, les bétons à base de chanvre, de lin et de colza, dont les cultures sont plutôt bien développées au niveau régional et national. De par leur composition, ces matériaux, à base de granulats végétaux associés à une matrice minérale, possèdent une forte sensibilité à l’humidité tout en conservant des performances thermiques intéressantes.Leurs propriétés sont en effet fortement liées à une porosité importante, qui leur confère une grande capacité à adsorber et restituer la vapeur d’eau contenue dans l’ambiance environnante ; cette spécificité vient s’interconnecter avec les échanges de chaleur d’une paroi ou d’un bâtiment. Il est donc indispensable de faire une analyse couplée des phénomènes de transferts thermiques et hygriques, non seulement pour déterminer les besoins en chauffage ou renouvellement d’air d’un local, mais aussi pour appréhender le confort des occupants et la durabilité de la construction.En s’appuyant sur de nombreux essais expérimentaux, les principales caractéristiques des matériaux mis en œuvre sont tout d’abord précisées. Est ensuite analysé plus particulièrement le comportement d’une paroi à l’échelle réelle, placée dans des conditions stationnaires ou variables d’humidité et/ou de température. Les propriétés des matériaux implémentées dans un modèle de simulation numérique (SPARK) permettent par ailleurs, et après validation expérimentale, une approche prédictive du comportement hygrothermique d’une paroi ou de l’enveloppe d’un bâtiment. A travers un modèle simplifié pour un local monozone, l’influence de l’inertie hygrique des matériaux sur le taux d’humidité relative de l’ambiance intérieure est mise en évidence / This thesis aims to enhance the use of bio-based materials such as concretes composed with hemp, flax or straw rapes, whose cultures are quite well developed at regional and national level. Due to their composition, these materials, plant-based aggregates associated with an inorganic matrix, have a high moisture sensitivity while retaining advantageous thermal performance.Their properties are indeed strongly associated with a high porosity, which gives them a great capacity to adsorb and release the water vapor contained in the surrounding atmosphere; this specificity comes interconnect with heat exchange of a wall or building. It is therefore essential to analyze the phenomena of coupled thermal and hygric transfers not only to determine the need for heating or for air exchanges, but also to apprehend occupant comfort and durability of construction.Built on many experimental trials, the main characteristics of the used materials are first specified. Then is specifically analyzed the behavior of a scaled wall, placed under stationary or variable conditions of humidity and / or temperature. Moreover, the properties of the materials provide, after implementation in a simulation model (SPARK) and experimental validation, a predictive approach of the hygrothermal behavior of a wall or a building envelope. Through a simplified model for a single zone room, is highlighted the influence of the hygric inertia of the materials on the relative humidity of the indoor atmosphere

MONTENEGRO, M.A. Efeito do extrato do bagaço do pendúculo de caju (Anacardium occidentale L.) contra Streptococcus mutans. 2012. 71 f. Dissertação. (MESTRADO EM BIOTECNOLOGIA) - Campus de Sobral, Universidade Federal do Ceará, Sobral, 2012. / Submitted by Djeanne Costa (djeannecosta@gmail.com) on 2017-08-23T13:48:10Z No. of bitstreams: 1 2012_dis_mamontenegro.pdf: 1919974 bytes, checksum: 87da3b64eae69ed89fb55fe9ea456063 (MD5) / Approved for entry into archive by Djeanne Costa (djeannecosta@gmail.com) on 2017-09-27T14:58:16Z (GMT) No. of bitstreams: 1 2012_dis_mamontenegro.pdf: 1919974 bytes, checksum: 87da3b64eae69ed89fb55fe9ea456063 (MD5) / Made available in DSpace on 2017-09-27T14:58:16Z (GMT). No. of bitstreams: 1 2012_dis_mamontenegro.pdf: 1919974 bytes, checksum: 87da3b64eae69ed89fb55fe9ea456063 (MD5) Previous issue date: 2012 / The Anacardium occidentale L, popularly known as cashew tree, occupies an important place among the fruit trees due to the increasing commercialization of its main products. In northeastern Brazil, its cultivation is one of the main agricultural activities in the region. Concentrating in the states of Ceará, Piauí and Rio Grande do Norte, it is used in folk medicine for various therapeutic purposes, including as an antimicrobial. The cashew apple bagasse is obtained after extracting the juice, being a major source of waste of agribusiness. The aim of this study was to evaluate the antimicrobial and antibiofilm potential of the hydroalcoholic extract of the cashew apple pomace (ECAP) against the Streptococcus mutans. It was determined the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and the preventive assay for biofilm formation through biomass quantification. The Streptococcus mutans strain UA159 was used for this intention. The antimicrobial assay results showed that the ECAP was considered bactericidal (250μg.mL) and was considered bactericidal at the concentration of 1000μg.mL. Inhibition in the biomass was observed at the minimum concentration of 250μg.mL. Thus, it was concluded that the EPAC shows antimicrobial and antibiofilm activity against Streptococcus mutans. These results demonstrate the potential of the ECAP as a possible biotechnological product in the field of dentistry. / O Anacardium occidentale L., conhecido popularmente como cajueiro, ocupa um lugar importante entre as plantas frutíferas devido à crescente comercialização dos seus principais produtos. No nordeste brasileiro, seu cultivo é uma das principais atividades agropecuárias da região. Concentrando-se nos estados do Ceará, Piauí e Rio Grande do Norte, é utilizado na medicina tradicional para diversos fins terapêuticos, inclusive, como antimicrobiano. O bagaço do caju é obtido após a extração do suco, sendo uma importante fonte de resíduos da agroindústria. O objetivo do presente trabalho foi avaliar o potencial antimicrobiano e antibiofilme do extrato hidroalcoólico do bagaço do pedúnculo do caju (EBPC) frente a bactéria Streptococcus mutans. No presente estudo, determinou-se a Concentração Inibitória Mínima (CIM), Concentração Bactericida Mínima (CBM) e avaliou-se a inibição da formação de biofilme através da quantificação da biomassa. Para isso, utilizou-se a cepa de S. mutans. Os resultados dos ensaios antimicrobianos mostraram que o EBPC teve ação bacteriostática (CIM = 250 μg.mL-1) e bactericida (CBM = 1000 μg.mL-1). Observou-se inibição da biomassa na concentração mínima de 250 μg.mL-1. Deste modo, concluiu-se que o EBPC apresentou atividade antimicrobiana e antibiofilme frente ao S. mutans. Estes resultados demonstraram o potencial do EBPC como um possível produto biotecnológico na área da odontologia.

Cette étude porte sur le comportement à l’impact et post-impact d’un composite 100% biosourcé, à fibres de lin et à matrice Polyamide 11. Une première étape a consisté à optimiser les paramètres de mise en oeuvre par thermocompression de ce composite. Deux types de tissus unidirectionnels de lin (A et B) ont été testés, ainsi que deux conditionnements de la résine PA11 : sous forme de film ou de poudre. Tout d’abord, les niveaux de température et de pression ont été optimisés sur un « premier set » de composites, élaborés à partir de lin A et de poudre de Polyamide 11. Ensuite, un « deuxième set » de composites a été étudié pour optimiser le choix des constituants. L’ensemble des composites fabriqués a été testé en traction, par DMA et par des mesures de taux de porosité. Il a été montré que la configuration optimale était obtenue avec le lin B et le Polyamide 11 sous forme de film, élaborée avec une température de 210°C et des paliers de pression de 25, 40 et 65 bars. Une analyse des endommagements créés en traction dans ce composite a été réalisée en couplant des observations par MEB et des enregistrements par émission acoustique. Il a ainsi été possible d’identifier quatre classes d’endommagement dans les composites [0]4 et [90]4, et cinq classes dans les composites [±45]s. Chacune de ces classes a été associée à une forme d'onde acoustique et à un type d’endommagement observé. La deuxième partie de ce travail a consisté à étudier l’influence d’un impact de 3,6J sur le comportement en traction et en compression de quatre séquences d’empilement : unidirectionnel [0]8, alterné [0/90]2s, sandwich [02/902]s et multidirectionnel [45/0/-45/90]s. Les grandeurs caractéristiques du comportement à l’impact ont tout d’abord été déterminées pour les quatre drapages.Les endommagements créés par l’impact ont été analysés par différentes techniques : observations visuelles,mesures topographiques, C-scan par ultrasons, et micro-tomographie. Les résultats ont montré que les configurations qui s’endommagent le moins à l’impact sont les drapages alterné et multidirectionnel. Les échantillons impactés ont ensuite été sollicités pour déterminer leurs propriétés post-impact, et les comparer aux résultats obtenus sur éprouvettes saines. Des essais de traction et de compression ont été réalisés sur cinq éprouvettes de chaque configuration. Lors de ces essais, les endommagements ont été suivis par émission acoustique, et les champs de déformation ont été mesurés par corrélation d’images. Les résultats ont montré que,grâce à la présence des plis à ±45°, le composite multidirectionnel présente les meilleures propriétés résiduelles.Enfin, un modèle post-impact a été mis en place, permettant, dans une première approche, en appliquant un module dégradé dans la zone impactée, de retrouver globalement les champs de déformations expérimentaux mesurés sur les différents drapages. / This PhD work deals with the impact and post-impact behavior of a fully bio-based composite made of flax fibresand Polyamide 11. The first goal was to optimize the hot press moulding parameters for manufacturing this composite. Two types of unidirectional flax fabrics (A and B) and two forms of Polyamide 11 (powder or film) were tested. At first, the pressure and temperature process values were optimized using a first set of composites made of flax A and Polyamide 11 in the form of powder. Then, an optimization of material components was conducted using a second set of composites. All the manufactured composites were tested by means of tensile tests, DMA and porosity measurements. Finally, an optimum configuration was determined: the composite flax B/PA 11 film manufactured with a temperature value of 210 °C and with gradual levels of pressure until 65 bars. Moreover, damage mechanisms were evaluated by acoustic emission and SEM observations during tensile tests. Four mechanisms were identified for the [0]4 and [90]4 composites and five for [±45]s composites. The second goal of this study was to study the effect of an impact of 3.6 J on the compression and tensile behaviors of four stacking sequences of this composite: unidirectional [0]8, alternated [0/90]2s, sandwich [02/902]s and multidirectional [45/0/- 45/90]s. The damage created by the impact in these four lay-ups was characterized thanks to different techniques: visual observations, topographic and C-scan measurements, and micro-tomography. It has been shown that the configurations with the smallest damage were the alternated and multidirectional composites. Then, impacted composites were tested by tensile and compressive loadings, and results were compared with the properties of non- impacted composites. Acoustic emission and digital image correlation were used to identify the damage and strain mechanisms of each type of composites. The results showed that, thanks to the presence of the ±45° plies, the multidirectional composite has the best post-impact behavior. Finally, a finite element model has been developed for simulating the post-impact behavior. As a first approach, a lower value of modulus has been implemented in the impacted area. It has allowed us to compare numerical and experimental strain fields for the different stacking sequences.

Ces travaux de doctorat ont été menés dans le cadre d'un contrat CIFRE entre l'entreprise Van Robaeys Frères, l'UBS et l'IFREMER. Les travaux visent à mieux comprendre certains paramètres influençant les propriétés de fibres de lin et celles de matériaux composites. Nous avons tout d'abord mis en évidence l'influence du degré de rouissage du lin sur les propriétés mécaniques des fibres de lin et celles de matériaux composites injectés lin/polypropylène. Ensuite, à l'aide d'une étude comparative, nous avons montré qu'il est possible de réaliser des matériaux composites unidirectionnels aux propriétés mécaniques très proches à partir de filasse ou d'étoupes de lin. Puis, l'influence de l'architecture de trois renforts non tissés de lin sur les propriétés mécaniques de composites à matrice thermoplastique a été soulignée. L'anisotropie des propriétés mécaniques de ces matériaux a été mise en évidence. Enfin, la connaissance des propriétés mécaniques de fibres de lin produites par l'entreprise Van Robaeys Frères a été approfondie. On note une relation directe entre les propriétés mécaniques des fibres et celles de composites à renfort unidirectionnel. La relation est plus complexe dans le cas de composites injectés à fibres courtes. / This research study has been carried out during a CIFRE joint project between the Van Robaeys Frères Company, UBS and IFREMER. The work aims to improve understanding of the properties of both flax fibres and composite materials reinforced with flax.First, the influence of the degree of retting of flax fibers on the tensile properties of single fibers and short fiber/polypropylene composites has been shown.Then, the properties of scutched flax and flax tow were compared. We have shown that it is possible to reach similar tensile properties for unidirectional composite materials manufactured from the two products.Moreover, the influence of three different flax nonwoven reinforcements on the mechanical properties of thermoplastic matrix composites was studied. These materials were found to show anisotropy of tensile properties.Finally, the mechanical properties of the flax fibres processed by the Van Robaeys Frères Company were examined. A straightforward relationship was found between the tensile properties of the fibres and the tensile properties of unidirectional composite materials. The relationship is more complex for short fibre injected composites.

lin-28 was first characterized as a developmental timing regulator in Caenorhabditis elegans. Loss of lin-28 function (lin-28(lf)) mutants skip the hypodermal cell fates specific to the 2nd larval stage. Here, we studied two aspects of lin-28 which had not yet been investigated. First, we show that lin-28(lf) mutants exhibit reduced fertility associated with abnormal somatic gonadal morphology. In particular, the abnormal spermatheca-uterine valve morphology of lin-28(lf) hermaphrodites traps embryos in the spermatheca, which disrupts ovulation and causes embryonic lethality. The same genes downstream of lin-28 in the regulation of hypodermal developmental timing also act downstream of lin-28 in somatic gonadal morphogenesis and fertility. Importantly, we find that hypodermal expression, but not somatic gonadal expression, of lin-28 is sufficient for restoring normal somatic gonadal morphology in lin-28(lf) mutants. We propose that the abnormal somatic gonadal morphogenesis of lin-28(lf) hermaphrodites results from temporal discoordination between the accelerated hypodermal development and normally timed somatic gonadal development. Thus, our findings exemplify how a cell-intrinsic developmental timing program can also control proper development of other interacting tissues, cell non-autonomously. We also investigated the expression patterns and functions of two lin-28 isoforms in C. elegans. Our analysis of spatial expression patterns suggests that lin-28a and lin-28b are co-expressed in diverse tissues. Consistently, neither of isoform specific knock-out mutant, lin-28a(lf) or lin-28b(lf), exhibits defects in hypodermal development, somatic gonad, or fertility, indicating functional redundancy of two isoforms. Our study will contribute to further investigation of lin-28 isoforms by providing the mutants of each isoform as well as the primary analysis of their phenotypes.