Installation of low-grade weirs in agricultural drainage ditches is being evaluated as an innovative, and cost effective, management practice that decreases nutrient concentrations and loads by increasing water volume and hydraulic residence time of the ditch. Results revealed that weirs significantly increased (P = 0.029) hydraulic residence time (HRT) and ditch water volumes, leading to considerable reductions in outflow water volumes (61%). Furthermore, ditches with weirs achieved greater (P = 0.09) cumulative outflow load reductions (96%) and greater (P = 0.029) concentration reductions during the biogeochemical reduction phase of the experiment. Similarly, field research from Terrace Ditch in Yazoo County, MS yielded significant percentage concentration reductions for baseflow (53%), stormflow (63%), and load (65%). Results from the experimental approach and field scale research offer promising insight into the future of low-grade weir’s establishment as an additional best management practice in agricultural landscapes.

Increasing awareness of hypoxia in coastal marine regions across the globe has led to creation of nutrient reduction strategies to protect water resources and organisms living in affected waters. In the Mississippi River Basin, the Governor’s Action Plan has called for a 45% load reduction of both, total nitrogen (N) and total phosphorus (P), to reduce the Gulf of Mexico hypoxic zone to a manageable size. Objectives of this dissertation aimed to determine nutrient reduction efficiencies of low-grade weirs, and to evaluate abundance and composition of microbial communities involved in key processes of denitrification following low-grade weir implementation in the Mississippi Delta. Results of this dissertation evidenced the efficiencies of low-grade weirs to reduce nutrient runoff to downstream waters as a viable BMP. Average median load reductions in N, P, and sediment of -5%, 23%, and 29%, respectively, were determined in ditches with low-grade weirs. Results highlighted more efficient reductions in P and sediment, and greater variability in N reductions during storm events, prompting management considerations toward BMP successes and limitations. Valuable insight towards seasonal nutrient fluxes in agricultural runoff due to spring fertilizer applications, increased rainfall patterns in the winter and spring, and drying-wetting cycles, was also evidenced by the data collected. It was determined that utilizing a three-scale sampling regime was most effective for capturing patterns of microbial community abundance and composition in ditches with low-grade weirs. Preliminary evidence towards weir proximity influencing microbial community abundance, and relationships between microbes and soil carbon and N was also found. Utilizing the three-scale sampling regime, microbial communities in multiple drainage ditches, with and without weirs, were investigated. Outcomes showed that weirs increased soil moisture, which subsequently increased functional gene abundance of 16S rRNA and nirS. Furthermore, weir implementation and associated constructions were not found to directly influence microbial community diversity, abundance, or chemical parameters. Results from this dissertation support the potential benefits of weirs to create suitable environments to physically reduce P and sediment loads and for denitrifying microbes to remediate N from agricultural runoff.

No description available.

Innate leukocytes manifest dynamic and distinct inflammatory responses upon challenges with rising dosages of pathogen associated molecular pattern molecules (PAMPs) such as lipopolysaccharide (LPS). To differentiate signal strengths, innate leukocytes may utilize distinct intra-cellular signaling circuitries modulated by adaptor molecules. Toll-interacting protein (Tollip) is one of the critical adaptor molecules in Toll-like receptor 4 (TLR4) signaling and potentially playing key roles in modulating the dynamic adaptation of innate leukocytes to varying dosages of external stimulants. While Tollip may serve as a negative regulator of NFkB signaling pathway in cells challenged with higher dosages of LPS, it acts as a positive regulator for low-grade chronic inflammation in leukocytes programmed by subclinical low-dosages of LPS. We aim to show recent progress in our understanding of complex innate leukocyte dynamics and its relevance in the pathogenesis of resolving versus non-resolving chronic inflammatory diseases. / Ph. D.

The food industry is a large consumer of industrial energy. A very large portion of this energy is needed in the form of thermal energy at medium to low temperatures. Fossil fuels remain the dominant sources of this energy. This combination provides various possibilities to reduce energy consumption and CO2 emissions with heat recovery, but also with the integration of solar process heat. Energy efficiency must provide the context, or background, of such considerations, and is therefore a very important aspect of them. It is a complex task to design an efficient heat supply with a variety of energy sources. An analysis of standards for energy audits, guides for energy efficiency and guides for solar process heat integration confirms that complexity. However, no available methodology considers all the necessary steps. These must range from analysis of the existing heat supply to the redesign of an efficient heat supply system. The focus must be on heat sources with waste heat and on solar process heat that might be used to complement the conventional sources. The design of a process heat system is mainly the task of design engineers in engineering offices. Specific tools and measures are needed to support these experts. However, the companies of the food industry sector employ their own energy engineers for energy issues. These people are actually the decision makers responsible for the configuration of the company energy supply systems, who also possess knowledge of the processes in their industry subsector. The expertise of the energy engineers varies within a broad range and is also connected to their area of responsibility. Therefore, it is important to consider these energy engineers when developing a methodology. The development of the methodology proposed herein consists first of the configuration of the tools and measures, which were assigned to four elements and functions. Second, the methodology so developed was applied at two companies in cooperation with their energy engineers, in detailed case studies. The feedback from the energy engineers is therefore a main objective and provides a background for evaluation of the usability of the methodology. It demonstrates the expertise required of the energy engineers, for the application of the tools and measures provided. Moreover, the development and application of the methodology involving real companies demonstrates the necessity of getting feedback from energy engineers. That finding is very important, and has been insufficiently considered in previous guides or methodologies. It is proposed that further work be aimed at providing additional case studies to extend the use of this methodology to other parts of the food industry.

This thesis investigates the use of the Stagnation-Point Reverse-Flow (SPRF) combustor geometry for burning low-grade solid fuels that are attractive for specific industrial applications because of their low cost and on-site availability. These fuels are in general, hard to burn, either because of high moisture and impurity-content, e.g. biomass, or their low-volatiles content, e.g., petroleum-coke. This results in various challenges to the combustor designer, for example reduced flame stability and poor combustion efficiency. Conventional solutions include preheating the incoming flow as well as co-firing with high-grade fuels. The SPRF combustor geometry has been chosen because it was demonstrated to operate stably on standard gaseous and liquid-fuels corresponding to ultra fuel-lean conditions and power densities at atmospheric-pressure around 20-25 MW/m3. Previous studies on the SPRF combustor have proven that the unique, reverse flow-geometry allows entrainment of near-adiabatic products into the incoming reactants, thereby enhancing the reactivity of the mixture. Further, the presence of the stagnation-end created a region of low mean velocities and high levels of unsteadiness and mixing-rates that supported the reaction-zones. In this study, we examine the performance of the SPRF geometry on a specific low grade solid fuel, petroleum coke. There are three main goals of this thesis. The first goal is the design of a SPRF combustor to operate on solid-fuels based on a design-scaling methodology, as well as demonstration of successful operation corresponding to a baseline condition. The second goal involves understanding the mode of operation of the SPRF combustor on solid-fuels based on visualization studies. The third goal of this thesis is developing and using reduced-order models to better understand and predict the ignition and quasi-steady burning behavior of dispersed-phase particles in the SPRF combustor. The SPRF combustor has been demonstrated to operate stably on pure-oxygen and a slurry made from water and petroleum-coke, both at the baseline conditions (125 kW, 18 g/s, ~25 µm particles) and higher power-densities and powder sizes. For an overall combustor length less than a meter, combustion is not complete (global combustion efficiency less than 70%). Luminance imaging results indicate the incoming reactant jet ignites and exhibits intense burning at the mid-combustor region, around 15 jet diameters downstream of the inlet, most likely due to enhanced mixing as a result of the highly unsteady velocity field. This roughly corresponds to the location of the reaction zones in the previous SPRF combustors operating on gas and liquid fuels. Planar laser visualization of the reacting flow-field using particle-scattering reveals that ignition of a significant amount of the reactants occurs only after the incoming jet has broken into reactant packets. Post-ignition, these burning packets burn out slowly as they reverse direction and exit the combustor on either side of the central injector. This is unlike the behavior in liquid and gas-fueled operation where the incoming reactants burned across a highly corrugated, thin-flame front. Based on these findings, as well as the results of previous SPRF studies, an idealized model of combustor operation based on a plug flow reactor has been developed. The predictions suggest that fuel-conversion efficiency is enhanced by the combustor operating pressure and lowered by the heat-losses. Overall, this effort has shown the SPRF geometry is a promising compact-combustor concept for self-sustained operation on low-grade solid-fuels for typical high-pressure applications such as direct steam-generation. Based on these findings, it is recommended that future designs for the specific application previously mentioned have a shorter base-combustor with lower heat-losses and a longer steam-generation section for injection of water.

The aim of the study was to identify molecular markers that can determine progression of low grade glioma. This was done using various approaches such as IDH1 and IDH2 mutation analysis, MGMT methylation analysis, copy number analysis using array comparative genomic hybridisation and identification of differentially expressed miRNAs using miRNA microarray analysis. IDH1 mutation was present at a frequency of 71% in low grade glioma and was identified as an independent marker for improved OS in a multivariate analysis, which confirms the previous findings in low grade glioma studies. IDH1 mutation was associated with MGMT promoter methylation when partially methylated tumours were grouped with methylated tumours. Grade II and grade III tumour comparison analysis revealed 14 novel significant miRNAs with differential expression. A miRNA signature was shown for histological subtypes, oligoastrocytoma and anaplastic oligoastrocytoma, following the miRNA expression analysis in grade II and grade III tumors based on histology. Oligoastrocytoma presented a more similar profile to oligodendroglioma, but anaplastic oligoastrocytoma was more similar to anaplastic astrocytoma. Five novel miRNAs were identified in grade III tumours, when comparing IDH1 mutant and IDH1 wild type tumours. Analysis of paired samples of primary/recurrent tumours revealed that additional genomic changes may promote tumour progression. For each of the pair, the two samples were genomically different and in each case, the reccurent tumours had more copy number aberrations than the corresponding primary tumours. Cell cultures derived from the tumour biopsies were not representative of the low grade glioma in vivo, which was evident from the differences identified in the miRNA expression and copy number changes in the paired samples. IDH1 mutation present in tumour biopsies was not maintained in their respective cell cultures. These findings give an insight into the molecular mechanisms involved in the tumourigenesis of low grade glioma and also tumour progression.

Les gliomes de bas-grade représentent la tumeur cérébrale la plus fréquente chez l’enfant. Elles sont caractérisées par un large spectre de sous-types tumoraux, très hétérogènes. Leur définition actuelle est principalement basée sur des critères histologiques ce qui représente une limite importante car ces classifications souffrent d’un manque de précision. Les progrès récents de la génomique nous permettent d’approfondir considérablement les connaissances sur la biologie de ces tumeurs afin d’enrichir leur classification actuelle. Ce travail présente une analyse approfondie des altérations génomiques de l’ADN et l’ARN des gliomes de bas-grade pédiatriques. Le premier niveau d’analyse se base sur l’analyse du séquençage à haut débit de 169 gliomes de bas-grade de l’enfant. Bien que les mutations des gènes BRAF et FGFR1 sont les plus fréquemment décrites dans ces tumeurs, nous avons identifié pour la première fois le réarrangement chromosomique MYB-QKI majoritairement associé aux gliomes angiocentriques. Dans un deuxième temps ce travail décrit l’analyse du transcriptome de 151 gliomes de bas grade extraits à partir de tissu conservé en paraffine. Nous avons observé des différences moléculaires en fonction de leur sous-type histologique, de la localisation tumorale et de leur statut BRAF. Dans le dernier volet de ce travail, nous avons testé la faisabilité d’isoler par cytométrie en flux une cellule unique en les distinguant selon un marqueur de différenciation glial (A2B5+ et A2B5-) et d’effectuer une analyse transcriptomique à haut-débit en séquençant l’ARN à l’échelle d’une cellule unique. Cette technique nous a permis de décrire des différences moléculaires intéressantes entre des cellules A2B5+ et A2B5-. Ces résultats soulignent l’intérêt d’exploiter des nouvelles technologies de pointe pour servir de base à l’étude des caractéristiques biologiques des cellules tumorales. / Low-grade gliomas represent the most frequent brain tumor arising during childhood. They are characterized by a broad spectrum of tumor types.The definition of low-grade gliomas has been mainly based on morphology. This histological classification of pediatric low-grade gliomas (PLGG), suffers from the lack of reproducibility. The recent progress in molecular biology and genetics has brought new insights in the biology of those tumors and allows better understanding of their biology. This work provides a comprehensive analysis of two different genetic approaches in PLGGs. The first part is based on the description of somatic genetic alterations of the DNA. Using a large PLGG cohort, we have dissect the genome of those tumors and draw the landscape of their genetic alteration. Although BRAF and FGFR1 alterations are predominantly altered, we have discovered a new translocation, MYB-QKI, that is almost exclusively present in a specific histological subgroup; angiocentric gliomasThe second part of the thesis describes transcriptomic analysis of bulk PLGGs. This work describes molecular differences between PLGGs from distinct histologies and arising from different locations in the brain as well as different BRAF mutation status.We were also able to test single-cell expression analyses in three pilocytic astrocytomas (PAs) using RNA-sequencing. In this experimental work we have successfully tested the hypothesis that we can isolate single-cells from fresh PLGG tumors in order to analyze the trasncriptome at a large scale. We observed that single-cells expressing A2B5, a glial progenitor marker, isolated in pediatric PAs are characterized as a distinct biological population. These results underline the importance to improve the precision of the transcriptomic studies to capture the molecular signal of tumor cells and further understand the different pattern between normal cells and tumor cells.

Introdução- Considerando o papel da glutamina como substrato energético para os enterácitos e como fornecedora de nitrogênio para o músculo esquelético, o estudo hipotetiza que a suplementação com glutamina pode contribuir na modulação da inflamação sistêmica e na preservação da massa muscular de idosos. Objetivos-avaliar os efeitos da suplementação com glutamina em alguns marcadores de inflamação e de composição corporal de idosos em risco de fragilidade. Métodos-estudo randomizado duplo-cego de intervenção. Foram recrutados idosos não institucionalizados que apresentaram de um a dois critérios de fragilidade biológica. Os idosos foram distribuídos em dois grupos: um recebeu glutamina(GLU) e outro maltodextrina, utilizado como placebo(PLA) durante seis meses, em duas doses diárias. No início e ao fmal do estudo os indivíduos foram avaliados pelo peso e estatura, para cálculo do índice de massa corporal(IMC), circunferências da cintura, quadril, panturrilha e braço(CC,CQ,CP e CB) e dobra cutânea tricipital(DCT); composição corporal porbioimpedância elétrica, observando os valores de resistência(R), reactância(Xc), ângulo de fase(AF), água extra e intracelular e capacitância; força de preensão palmar(FPM); concentração sérica de citocinas (IL-IO, IL-6 e TNF-α); concentração sérica de creatinina e ureia para avaliação de função renal, por meio do cálculo da depuração de creatinina(Cockcorft&Galt); ingestão alimentar pelo recordatório alimentar de 24 horas e diário alimentar; nível de atividade fisica pelo questionário de Baecke; funcionamento intestinal pela escala de Bristol. Resultados-Foram incluídos no estudo 49 idosos, divididos 25 no GLU e 24 no PLA. Embora nenhuma das variáveis tenha apontado diferença significativa na comparação relacionada ao tempo (antes e depois da suplementação) e ao tratamento (glutamina ou placebo), a evolução de algumas variáveis indicou vantagens para o GLU, a saber: maiores valores de FPM; maiores valores do IMC, ligeiro aumento da CB e ligeira diminuição da DCT, menores variações das outras medidas corporais; valores de Xc, AF e água intracelular mostraram um melhor estado celular no GLU. Conclusões-A suplementação com glutamina em idosos em risco de fragilidade mostrou variações que podem ser interpretadas como possíveis beneficios ao funcionamento intestinal e à composição corporal. Dada a grande variabilidade dos resultados, não foi possível estabelecer diferenças estatísticas que pudessem confirmar essas variações. Estudos com amostras maiores, e com medidas prévias da permeabilidade intestinal, podem esclarecer os achados. / Introduction-Having in mind the role of glutamine as an energy substrate to enterocytes, as well as a nitrogen reserve to skeletal muscle, the study hypothesized that glutamine supplementation is capable of modulating the systemic inflammation and improving muscle mass as consequence. Objectives-to evaluate the effects of glutamine supplementation on some inflammatory markers and on the body composition of elderly in risk of frailty. Methods-randomized double-blind clinicai trial (RCT). This study included community-dwelling elderly (above 65 years old), who presented one or two criteria to develop frailty syndrome. The elderly were distributed in two groups, one of them received glutamine (GLU) and the other received placebo (PLA; maltodextrin) for 6 months, in two daily doses. In beginning and cnd of the experiment, the participants were evaluated for body weight and body height, to calculate the body mass index(BMI); waist, hip, calf and arm circumferences(WC,HC,CC,AC); tricipital skin folder(TSF); body composition by bioelectrical impedance measuring resistance, reactance, capacitance, phase angle, extra and intracellular water; grip strength; serum levei of inflammatory cytokines(IL-l0, IL-6 e TNF-α); serum creatinine and urea with evaluation ofkidney function by Cockcroft & Galt equation; food intake by a 24h food record; physical activity level by Baecke questionnaire; bowel function by Bristol scale. Results-49 participants were recruited, and distributed to both groups (GLU= 24 and PLA=24). Although none of the variables showed significant statistical differences, comparing together time (before and after) and group (glutamine or placebo), but evoluation of variables to demonstrate advantages to GLU supplementation, such as: higher grip strength values; higher values of BMI, slight enhance of AC and slight reduction in TSF, lower variation in anthropometric measures; BIA results showed better cellular conditions in GLU group (from reactance, phase angle and intracellular water). Conclusions - According to our experimental conditions, the glutamine supplementation in elderly at frailty risk showed some variability which could be interpreted as benefits either to body composition and gut function. However, due to the high variability presented in the results, it was not possible to find statistical significances, to confirm those finds. Studies involving a larger sample size, and preferably with measures of intestinal permeability, could clarify our results.

Les gliomes diffus de bas grade sont des tumeurs cérébrales des jeunes adultes. Dans cette thèse, nous nous intéressons à la segmentation et à la modélisation de ces tumeurs. Dans la première partie du manuscrit, nous étudions la segmentation des gliomes diffus de bas grade à base de différentes méthodes manuelles et semi-automatiques. La délimitation de ces tumeurs peut être problématique en raison de leur caractère très infiltrant et inhomogène. En pratique clinique, le suivi des gliomes diffus de bas grade repose sur l'estimation du volume tumoral, soit par une segmentation suivie d'une reconstruction logicielle, soit par la méthode des trois diamètres. Pour la segmentation, elle est manuelle et est exécutée par des praticiens sur des IRM en pondération FLAIR ou T2. La méthode des trois diamètres est rapide mais s'avère difficile à implémenter dans le cas de gliomes diffus de bas grade très infiltrants ou en post-traitement. La solution par segmentation manuelle et reconstruction logicielle du volume est chronophage mais demeure plus précise en comparaison de la méthode des trois diamètres. Nous étudions ici la reproductibilité de la segmentation manuelle avec le logiciel OsiriX en réalisant un test subjectif dans le Living Lab PROMETEE de TELECOM Nancy. Les résultats de cette étude montrent que ni la spécialité du praticien ni le nombre d’années d’expérience ne semblent impacter significativement la qualité de la segmentation. Nous comparons par ailleurs les résultats obtenus à ceux d'un deuxième test où nous appliquons la méthode des trois diamètres. Enfin, nous explorons deux algorithmes de segmentation semi-automatique basés, respectivement, sur les contours actifs et sur la méthode des level set. Même si la segmentation automatique semble être une voie prometteuse, nous recommandons aujourd’hui l’utilisation de la segmentation manuelle du fait notamment du caractère diffus des gliomes de bas grade qui rend le contour complexe à délimiter. La seconde partie du manuscrit est consacrée à la modélisation des gliomes diffus de bas grade eux-mêmes ou, plus exactement, à la modélisation de l'évolution du diamètre tumoral en phase de chimiothérapie. La prise en charge thérapeutique des patients atteints de ces tumeurs inclut en effet souvent une chimiothérapie. Pour ce travail, nous nous intéressons à la chimiothérapie par Témozolomide en première ligne de traitement. Une fois le traitement entamé, les praticiens aimeraient déterminer l'instant optimal d'arrêt de traitement. Nous proposons une modélisation statistique du diamètre tumoral sous chimiothérapie. Cette modélisation s'appuie sur des modèles de régression linéaire et exponentielle. Elle permet de prédire le diamètre tumoral à partir d'un jeu de données d'apprentissage et d'alerter le clinicien sur l'état d'évolution du diamètre sous traitement. Nous espérons que ces modèles pourront un jour être utilisés comme un outil dans la planification de la chimiothérapie en milieu clinique. / Diffuse low-grade gliomas are brain tumors of young adults. In this thesis, we focus on the segmentation and on the modeling of these tumors. In the first part of the manuscript, we study the segmentation of diffuse low-grade gliomas based on different manual and semi-automatic methods. The delineation of these tumors can be problematic because of their very infiltrating and inhomogeneous nature. In clinical practice, the monitoring of diffuse low-grade gliomas is based on the estimation of tumor volume, obtained either through a segmentation followed by a software reconstruction or through the three diameters method. As for the segmentation, it is manual and it is performed by practitioners on FLAIR-weighted or T2-weighted MRI.The three diameters approach is fast but it is difficult to implement in the case of highly infiltrating diffuse low grade gliomas or after a treatment. The manual segmentation and software-based volume reconstruction solution is time-consuming but it remains more accurate in comparison with the three diameters method. We investigate in this work the reproducibility of the manual segmentation with the OsiriX software by performing a subjective test in the Living Lab PROMETEE in TELECOM Nancy. The results of this study show that neither the practitioners' specialty nor their number of years of experience seem to have a significant impact on the quality of the segmentation. We also compare the results to those of a second test where we apply the three diameters method. Finally, we explore two semi-automatic segmentation algorithms which are, respectively, based on active contours and on the level set method. Even if automatic segmentation seems to be a promising avenue, we recommend for now the use of manual segmentation because of the diffuse nature of low-grade gliomas, which makes the tumor's contours complex to delineate. The second part of the manuscript is dedicated to the modeling of diffuse low-grade gliomas themselves or, to be more precise, to the modeling of the evolution of the tumor's diameter during chemotherapy. The therapeutic management of patients with these tumors often includes indeed chemotherapy. For this work, we focus on Temozolomide chemotherapy in first-line treatment. After the beginning of the treatment, the practitioners would like to determine the optimum time of discontinuation. We propose a statistical modeling of tumor diameter under chemotherapy. This modeling is based on linear and exponential regression models. It can predict the tumor diameter from a set of training dataset and can alert the clinician on the state of change in diameter under treatment. We hope that these models will, eventually, be used as a tool in the planning of chemotherapy in a clinical environment.