Evaluation du potential fibreux et textile de la canne à sucre (Saccharum officinarum L.)

This doctoral dissertation deals with extraction and mechanical characterization of sugarcane fibers. From bagasse, the fibrous residue left from the sugar mill, several extraction conditions were investigated in order to extract technical sugarcane fibers. At first, morphological and physical characterization were analyzed, based on their sections and longitudinal profiles. Thus, mean size, fiber fineness and scattering were studied regarding adjusting parameters barbe and hauteur, for the fiber length distribution as weighted mean.Different types of technical fibers were obtained and their mechanical characterization as bending and tensile properties linked with the extraction conditions. Mechanical performances of the extracted fibers are common to other natural fibers that confirm their textile potential. To valorize these fibers, some experiments were conducted by producing sugarcane yarn. A micro-spinning were piloted for a 100% bagasse and 30/70% cotton/bagasse yarn made. Finally, an introduction to an environmental approach was analyzed, based on the lifecycle analysis from the sugarcane culture to the fiber extraction, opening new perspectives to study. The results show that good fibers can be extracted from sugarcane, thanks to its chemical and physical composition, but also can be characterized for textile application.Ce travail de thèse porte sur l’extraction et la caractérisation mécanique des fibres de canne à sucre. A partir de la bagasse de canne à sucre, résidu fibreux de l’industrie sucrière, des techniques d’extractions sont mises en place afin d’extraire des fibres techniques, dont l’analyse des propriétés chimiques et physico-mécaniques définira par la suite, les domaines d’application textile possibles. Les fibres de canne obtenues ont d’abord été étudiées d’un point de vue physique et morphologique, à partir de mesures et d’observations de leurs sections et de leurs profils. Ainsi, l’analyse de la distribution en diamètre et en longueur des fibres ont été étudiés avec l’établissement de paramètres de centrage barbe et hauteur (longueur pondérée à la masse), ont permis de déterminer leurs tailles moyennes, leurs finesses et leurs dispersions tout en vérifiant l’effet des conditions de traitement. Ont ainsi été obtenus différents types de fibres, présentant des propriétés mécaniques (en flexion et en traction) variées en relation avec les changements de structure dus à l’extraction. Les performances mécaniques de ces fibres restent comparables aux autres fibres naturelles, confirmant ainsi leur potentiel textile. Une première piste de valorisation de ces fibres a été envisagée lors de la fabrication d’un fil de canne à sucre. Des essais de filature ont ainsi été menés sur micro-filature, en 100% fibres de canne mais aussi en mélange 30-70% coton/bagasse.Enfin, une introduction à l’approche environnementale basée sur l’analyse de cycle de vie, a été succinctement abordée, ouvrant le champ à d’autres études. Les résultats montrent que le potentiel textile de la canne à sucre est quantifiable, et que ses fibres extractibles, sont comparables à d’autres fibres naturelles non conventionnelles utilisés dans le domaine textile

Mechanical properties of flax and hemp yarns designed for the manufacturing of geotextiles. Improvement of the resistance to soil born microorganisms.

Geotextiles are widely used to stabilize river banks from erosion when these ones are restored into vegetal covered areas as mentioned by European regulations. For these applications imported coir (coconut shell fibres) based geotextiles are generally used because coir fibres show a good resistance to soil degradation. In Europe, flax and hemp plants are already grown for textile, building or oil applications. By-products of these industries such as flax tows and short hemp fibres were used to manufacture yarns. The resistance to degradation via the measurement of the mechanical properties of these yarns submitted to enzymatic (cellulase) and microbial attacks (Cellvibrio gandavensis) mimicking soil degradation was evaluated. Large decreases in mechanical properties were observed, even though these ones were still higher than the as received reference coir material. After impregnation by chitosan of the fibres, the tensile properties of the yarns globally remained unchanged after severe attacks. The chitosan acts as a protection against the soil microorganism attacks. As a consequence, flax and hemp by-products could be good candidates for local manufacturing of biodegradable geotextiles

PREPARATION OF CELLULOSIC FIBERS FROM SUGARCANE FOR TEXTILE USE

6 pagesInternational audienceThe production of natural fibers is not sufficient to accommodate the textile needs of the growing world population. Therefore, textile research is exploring alternative natural resources to produce fibers. Though typically known for its nutritional use, the sugarcane can also be used for textile production because of its high fiber content.The aim of our study was to extract fibers from sugarcane and to analyze their mechanical behavior. Cane particles were treated with an alkaline solution in order to get cellulosic fibers. Physical and mechanical characterizations were carried out on these fibers: linear density, fineness, tensile properties, and bending rigidity. Their microstructure was analyzed to better understand their behavior. The results showed a strong influence of extraction parameters on the characteristics of fibers. Depending on these parameters, fibers fineness ranged from 8 to 80 tex, length ranged from 19 to 62 mm, and tenacity ranged from 7 and 25 cN/tex

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Evaluation of the fibrous and textile potential of sugarcane (Saccharum officinarum L.)

Ce travail de thèse porte sur l’extraction et la caractérisation mécanique des fibres de canne à sucre. A partir de la bagasse de canne à sucre, résidu fibreux de l’industrie sucrière, des techniques d’extractions sont mises en place afin d’extraire des fibres techniques, dont l’analyse des propriétés chimiques et physico-mécaniques définira par la suite, les domaines d’application textile possibles. Les fibres de canne obtenues ont d’abord été étudiées d’un point de vue physique et morphologique, à partir de mesures et d’observations de leurs sections et de leurs profils. Ainsi, l’analyse de la distribution en diamètre et en longueur des fibres ont été étudiés avec l’établissement de paramètres de centrage barbe et hauteur (longueur pondérée à la masse), ont permis de déterminer leurs tailles moyennes, leurs finesses et leurs dispersions tout en vérifiant l’effet des conditions de traitement. Ont ainsi été obtenus différents types de fibres, présentant des propriétés mécaniques (en flexion et en traction) variées en relation avec les changements de structure dus à l’extraction. Les performances mécaniques de ces fibres restent comparables aux autres fibres naturelles, confirmant ainsi leur potentiel textile. Une première piste de valorisation de ces fibres a été envisagée lors de la fabrication d’un fil de canne à sucre. Des essais de filature ont ainsi été menés sur micro-filature, en 100% fibres de canne mais aussi en mélange 30-70% coton/bagasse.Enfin, une introduction à l’approche environnementale basée sur l’analyse de cycle de vie, a été succinctement abordée, ouvrant le champ à d’autres études. Les résultats montrent que le potentiel textile de la canne à sucre est quantifiable, et que ses fibres extractibles, sont comparables à d’autres fibres naturelles non conventionnelles utilisés dans le domaine textile.This doctoral dissertation deals with extraction and mechanical characterization of sugarcane fibers. From bagasse, the fibrous residue left from the sugar mill, several extraction conditions were investigated in order to extract technical sugarcane fibers. At first, morphological and physical characterization were analyzed, based on their sections and longitudinal profiles. Thus, mean size, fiber fineness and scattering were studied regarding adjusting parameters barbe and hauteur, for the fiber length distribution as weighted mean. Different types of technical fibers were obtained and their mechanical characterization as bending and tensile properties linked with the extraction conditions. Mechanical performances of the extracted fibers are common to other natural fibers that confirm their textile potential. To valorize these fibers, some experiments were conducted by producing sugarcane yarn. A micro-spinning were piloted for a 100% bagasse and 30/70% cotton/bagasse yarn made. Finally, an introduction to an environmental approach was analyzed, based on the lifecycle analysis from the sugarcane culture to the fiber extraction, opening new perspectives to study. The results show that good fibers can be extracted from sugarcane, thanks to its chemical and physical composition, but also can be characterized for textile application

The content and meaning of administrative work: a qualitative study of nursing practices

International audienceAIM:To investigate the content and meaning of nurses' administrative work.BACKGROUND:Nurses often report that administrative work keeps them away from bedside care. The content and meaning of this work remains insufficiently explored.DESIGN:Comparative case studies.METHOD:The investigation took place in 2014. It was based on 254 hours of observations and 27 interviews with nurses and staff in two contrasting units: intensive care and long-term care. A time and motion study was also performed over a period of 96 hours.RESULTS:Documentation and Organizational Activities is composed of six categories; documenting the patient record, coordination, management of patient flow, transmission of information, reporting quality indicators, ordering supplies- stock management Equal amounts of time were spent on these activities in each case. Nurses did not express complaints about documentation in intensive care, whereas they reported feeling frustrated by it in long-term care. These differences reflected the extent to which these activities could be integrated into nurses' clinical work and this is in turn was related to several factors: staff ratios, informatics, and relevance to nursing work.CONCLUSION:Documentation and Organizational Activities are a main component of care. The meaning nurses attribute to them is dependent on organizational context. These activities are often perceived as competing with bedside care, but this does not have to be the case. The challenge for managers is to fully integrate them into nursing practice. Results also suggest that nurses' Documentation and Organizational Activities should be incorporated into informatics strategies