30 research outputs found

    Urea hydrogen peroxide, Detonation performance

    Get PDF
    Carbamide Peroxide is commonly used in the cosmetic and pharmaceutical industries as a solid source of hydrogen peroxide. This adduct of Urea and Hydrogen Peroxide (UHP) has explosive properties, which have been only recently studied, highlighting its behaviour of non-ideal tertiary explosive and detonability at large scale. Our work focussed on investigating UHP detonability in the 100 g-scale. A maximum of experimental data, collected from combining laboratory and underwater measurement campaigns, is required to evaluate the detonation performance of non-ideal explosives. Our lab results confirmed self-sustained detonation under heavy confinement, with observed detonation velocities consistent with literature values from large-scale field experiments. We further fired UHP charges underwater and quantified brisance and explosive power respectively from underwater shock pressure and bubble period. By comparing experimental results and numerical simulations, we could assess the level of agreement between lab and underwater detonation performance parameters

    Health economic evaluation of gene replacement therapies:Methodological issues and recommendations

    Get PDF
    Objective: To provide recommendations for addressing previously identified key challenges in health economic evaluations of Gene Replacement Therapies (GRTs), including: 1) the assessment of clinical effectiveness; 2) the valuation of health outcomes; 3) the time horizon and extrapolation of effects beyond trial duration; 4) the estimation of costs; 5) the selection of appropriate discount rates; 6) the incorporation of broader elements of value; and 7) affordability. Methods: A literature review on economic evaluations of GRT was performed. Interviews were conducted with 8 European and US health economic experts with experience in evaluations of GRT. Targeted literature reviews were conducted to investigate further potential solutions to specific challenges. Recommendations: Experts agreed on factors to be considered to ensure the acceptability of historical cohorts by HTA bodies. Existing prospective registries or, if not available, retrospective registries, may be used to analyse different disease trajectories and inform extrapolations. The importance of expert opinion due to limited data was acknowledged. Expert opinion should be obtained using structured elicitation techniques. Broader elements of value, beyond health gains directly related to treatment, can be considered through the application of a factor to inflate the quality-adjusted life years (QALYs) or a higher cost-effectiveness threshold. Additionally, the use of cost-benefit analysis and saved young life equivalents (SAVE) were proposed as alternatives to QALYs for the valuations of outcomes of GRT as they can incorporate broader elements of value and avoid problems of eliciting utilities for paediatric diseases. Conclusions: While some of the limitations of economic evaluations of GRT are inherent to limited clinical data and lack of experience with these treatments, others may be addressed by methodological research to be conducted by health economists

    RNA G-Quadruplexes in the model plant species Arabidopsis thaliana: prevalence and possible functional roles

    Get PDF
    Tandem stretches of guanines can associate in hydrogen-bonded arrays to form G-quadruplexes, which are stabilized by K+ ions. Using computational methods, we searched for G-Quadruplex Sequence (GQS) patterns in the model plant species Arabidopsis thaliana. We found ∼1200 GQS with a G3 repeat sequence motif, most of which are located in the intergenic region. Using a Markov modeled genome, we determined that GQS are significantly underrepresented in the genome. Additionally, we found ∼43 000 GQS with a G2 repeat sequence motif; notably, 80% of these were located in genic regions, suggesting that these sequences may fold at the RNA level. Gene Ontology functional analysis revealed that GQS are overrepresented in genes encoding proteins of certain functional categories, including enzyme activity. Conversely, GQS are underrepresented in other categories of genes, notably those for non-coding RNAs such as tRNAs and rRNAs. We also find that genes that are differentially regulated by drought are significantly more likely to contain a GQS. CD-detected K+ titrations performed on representative RNAs verified formation of quadruplexes at physiological K+ concentrations. Overall, this study indicates that GQS are present at unique locations in Arabidopsis and that folding of RNA GQS may play important roles in regulating gene expression

    Acheter. Une caméra térahertz

    No full text
    De nombreux laboratoires de recherche académiques utilisent des caméras térahertz pour la caractérisation de sources, l’alignement des bancs optiques, l’étude de phénomènes physiques… En parallèle, de plus en plus d’équipes de recherche appliquée, dans les instituts de R&D et chez des industriels, mettent en œuvre ces caméras pour investiguer des applications de l’imagerie térahertz dans des domaines variés comme la sécurité, le contrôle non destructif, l’environnement ou la santé. En réponse à ces besoins, une offre commerciale de caméras térahertz non refroidies commence à monter en maturité

    Etude théorique et expérimentale du réglage électromagnétique d'une cavité radio-fréquence quadripolaire accélératrice d'un faisceau intense d'ions

    No full text
    PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

    Immersion in refractive index matching liquid for 2D and 3D terahertz imaging

    No full text
    International audienceWe investigate the possibility to limit refraction effect at interfaces between a sample and a liquid medium to improve resolution in 2D and 3D terahertz imaging. Indeed, an important part of the terahertz beam is reflected, diffracted and refracted at each interfaces because of refractive index mismatch. We propose to adapt the refractive index of medium around the sample replacing surrounding air by medium with an optimized refractive index and low absorption coefficient. This approach will be developed to recover good dimension for metrology and to improve reconstruction by tomography algorithm

    Gestion du pâturage au printemps en système bovin allaitant : diversité des pratiques en Saône-et-Loire

    No full text
    National audienceGrazed grass is the cheapest forage for making meat'. In order to incite farmers to make their forage systems more self-sufficient and thrifty, the 'Chambre d'Agriculture de Saone-et-Loire' (a professional agricultural organization for that departement) has been monitoring for five years the management of spring grazing on 23 farms. The analysis of farmers' practices lead to considerations as to put to the best use the grazed grass, according to the pedo-climatic conditions and the constraints of the farms. With the aim of optimizing the pasture resources in order to limit the purchase of concentrates and to cope with the climatic hazards, the study of the management of spring grazing in a suckler-cattle system has focused on the observation of the growth and utilization of grass by over 80 batches of animals during five years. The diversity of the types of grazing management was characterized by the Volume of Available Grass per LU and by the resilience in case of drought. The analysis made at the level of the whole farm lead to the definition of 5 types of grazing, characterized (i) by the farmer's aim (high-quality grass, security, or a compromise between the two), and (ii) by the strategy implemented and its adjustments in case of hazards. The potentialities of the environment as well as the field pattern exert a strong influence on the type of grazing chosen by the farmer. Possibilities of progress exist for each of the grazing types identified.Certains éleveurs bovin allaitant ont pour habitude de sous utiliser l’herbe au printemps, ce qui est à l’origine de mauvaises performances techniques et économiques. Pour bâtir les bases d’un conseil pertinent sur la prairie, la Chambre d’Agriculture de Saône-et-Loire a étudié de plus prés la gestion du pâturage au printemps. La méthode de travail a consisté à connaître et analyser la diversité les pratiques de pâturage à partir d’un réseau de 23 exploitations, puis à schématiser les pratiques, en tenant compte du fonctionnement global de l'exploitation. A partir de ce schéma, différents cas types ont été identifiés. Enfin, les marges de progrès ont été proposées pour le transfert au développement. Six types sont repérés, reflétant la stratégie de l’éleveur et la « robustesse » des systèmes de pâturage face à la sécheresse. Ils correspondent à des milieux différents, mais dépendent aussi de l’organisation du travail ou des objectifs zootechniques. Le premier type pilote en flux très tendus, en maintenant l’herbe rase, dans les milieux à fort potentiel. Le dernier type pilote en flux très sécuritaires, laissant pousser l’herbe, souvent dans des milieux séchants et avec un parcellaire très dispersé. Entre ces deux extrêmes, une gestion en « compromis » est observé, notamment dans les milieux hydromorphes. Des marges de progrès sont possibles sur le terrain : il s’agit de sécuriser au mieux la gestion pour faire face aux aléas climatiques, tout en évitant le gaspillage

    De luchtzakken van vogels: visualisatie bij de kip door middel van de afgietseltechniek

    No full text
    Because of their important physiological functions, the avian air sacs have already been described in detail. However, three-dimensional illustrations, which are very useful for clinical research and in particular for medical imaging, are sparse. Therefore, in the present study the air sac system of young chickens was visualized using the corrosion casting technique. The 9 air sacs that could be demonstrated were the unpaired clavicular air sac and the paired cervical, cranial and caudal thoracic, and abdominal air sacs. The latter were by far the largest and were interwoven with the abdominal organs. The numerous diverticles extending from the air sacs were rather small. This might be the result of the applied technique or the fact that the air sac system has not yet been fully developed in young birds. Further studies investigating potential species differences or conformational changes of the air sacs in growing animals are valuable
    corecore