348 research outputs found

    Un modèle de poutre à section fortement déformable. Application au pliage at au déploiement de mètres rubans.

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    National audienceSee http://hal.archives-ouvertes.fr/docs/00/59/28/67/ANNEX/r_D90G1MU4.pd

    Assessment of radiant temperature in a closed incubator

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    In closed incubators, radiative heat loss (R) which is assessed from the mean radiant temperature [Formula: see text] accounts for 40–60% of the neonate’s total heat loss. In the absence of a benchmark method to calculate [Formula: see text]—often considered to be the same as the air incubator temperature—errors could have a considerable impact on the thermal management of neonates. We compared [Formula: see text] using two conventional methods (measurement with a black-globe thermometer and a radiative “view factor” approach) and two methods based on nude thermal manikins (a simple, schematic design from Wheldon and a multisegment, anthropometric device developed in our laboratory). By taking the [Formula: see text] estimations for each method, we calculated metabolic heat production values by partitional calorimetry and then compared them with the values calculated from [Formula: see text] and [Formula: see text] measured in 13 preterm neonates. Comparisons between the calculated and measured metabolic heat production values showed that the two conventional methods and Wheldon’s manikin underestimated R, whereas when using the anthropomorphic thermal manikin, the simulated versus clinical difference was not statistically significant. In conclusion, there is a need for a safety standard for measuring [Formula: see text] in a closed incubator. This standard should also make available estimating equations for all avenues of the neonate’s heat exchange considering the metabolic heat production and the modifying influence of the thermal insulation provided by the diaper and by the mattress. Although thermal manikins appear to be particularly appropriate for measuring [Formula: see text], the current lack of standardized procedures limits their widespread use

    Molecular Junctions for Terahertz Switches and Detectors

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    Molecular electronics targets tiny devices exploiting the electronic properties of the molecular orbitals, which can be tailored and controlled by the chemical structure/conformation of the molecules. Many functional devices have been experimentally demonstrated; however, these devices were operated in the low frequency domain (mainly, dc to MHz). This represents a serious limitation for electronic applications, albeit molecular devices working in the THz regime were theoretically predicted. Here, we experimentally demonstrate molecular THz switches at room temperature. The devices consist of self-assembled monolayers of molecules bearing two conjugated moieties coupled through a non-conjugated linker. These devices exhibit clear negative differential conductance behaviors (peaks in the current-voltage curves), as confirmed by ab initio simulations, which were reversibly suppressed under illumination with a 30 THz wave. We analyze how the THz switching behavior depends on the THz wave properties (power, frequency), and we benchmark that these molecular devices would outperform actual THz detectors.Comment: Full paper, figures and supporting informatio

    pKa tuning in quadrupolar-type two-photon ratiometric fluorescent membrane probes

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    International audienceTwo bolaamphiphilic quadrupoles built from a fluorene core conjugated with azine endgroups were designed and successfully used to stain GUV membranes. Their quadrupolar character induces both a shift of the pKa values close to the physiological pH and large two-photon absorption responses (i.e. over 1000 GM for acidic forms). As such they hold promise as ratiometric two-photon pH probes for monitoring slight variations of pH near cell membranes using two-photon excitation in the NIR regio

    Comparative genomic and proteomic analyses of two Mycoplasma agalactiae strains: clues to the macro- and micro-events that are shaping mycoplasma diversity

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    Background: While the genomic era is accumulating a tremendous amount of data, the question of how genomics can describe a bacterial species remains to be fully addressed. The recent sequencing of the genome of the Mycoplasma agalactiae type strain has challenged our general view on mycoplasmas by suggesting that these simple bacteria are able to exchange significant amount of genetic material via horizontal gene transfer. Yet, events that are shaping mycoplasma genomes and that are underlining diversity within this species have to be fully evaluated. For this purpose, we compared two strains that are representative of the genetic spectrum encountered in this species: the type strain PG2 which genome is already available and a field strain, 5632, which was fully sequenced and annotated in this study. Results: The two genomes differ by ca. 130 kbp with that of 5632 being the largest (1006 kbp). The make up of this additional genetic material mainly corresponds (i) to mobile genetic elements and (ii) to expanded repertoire of gene families that encode putative surface proteins and display features of highly-variable systems. More specifically, three entire copies of a previously described integrative conjugative element are found in 5632 that accounts for ca. 80 kbp. Other mobile genetic elements, found in 5632 but not in PG2, are the more classical insertion sequences which are related to those found in two other ruminant pathogens, M. bovis and M. mycoides subsp. mycoides SC. In 5632, repertoires of gene families encoding surface proteins are larger due to gene duplication. Comparative proteomic analyses of the two strains indicate that the additional coding capacity of 5632 affects the overall architecture of the surface and suggests the occurrence of new phase variable systems based on single nucleotide polymorphisms. Conclusion: Overall, comparative analyses of two M. agalactiae strains revealed a very dynamic genome which structure has been shaped by gene flow among ruminant mycoplasmas and expansion-reduction of gene repertoires encoding surface proteins, the expression of which is driven by localized genetic micro-events

    Progressive Structural Defects in Canine Centronuclear Myopathy Indicate a Role for HACD1 in Maintaining Skeletal Muscle Membrane Systems

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    Mutations in HACD1/PTPLA cause recessive congenital myopathies in humans and dogs. Hydroxyacyl-coA dehydratases are required for elongation of very long chain fatty acids, and HACD1 has a role in early myogenesis, but the functions of this striated muscle-specific enzyme in more differentiated skeletal muscle remain unknown. Canine HACD1 deficiency is histopathologically classified as a centronuclear myopathy (CNM). We investigated the hypothesis that muscle from HACD1-deficient dogs has membrane abnormalities in common with CNMs with different genetic causes. We found progressive changes in tubuloreticular and sarcolemmal membranes and mislocalized triads and mitochondria in skeletal muscle from animals deficient in HACD1. Furthermore, comparable membranous abnormalities in cultured HACD1-deficient myotubes provide additional evidence that these defects are a primary consequence of altered HACD1 expression. Our novel findings, including T-tubule dilatation and disorganization, associated with defects in this additional CNM-associated gene provide a definitive pathophysiologic link with these disorders, confirm that dogs deficient in HACD1 are relevant models, and strengthen the evidence for a unifying pathogenesis in CNMs via defective membrane trafficking and excitation-contraction coupling in muscle. These results build on previous work by determining further functional roles of HACD1 in muscle and provide new insight into the pathology and pathogenetic mechanisms of HACD1 CNM. Consequently, alterations in membrane properties associated with HACD1 mutations should be investigated in humans with related phenotypes

    Recommendations for radiation therapy in oligometastatic prostate cancer:An ESTRO-ACROP Delphi consensus

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    Background and purpose: Oligometastatic prostate cancer is a new and emerging treatment field with only few prospective randomized studies published so far. Despite the lack of strong level I evidence, metastasis-directed therapies (MDT) are widely used in clinical practice, mainly based on retrospective and small phase 2 studies and with a large difference across centers. Pending results of ongoing prospec-tive randomized trials, there is a clear need for more consistent treatment indications and radiotherapy practices.Material and methods: A European Society for Radiotherapy and Oncology (ESTRO) Guidelines Committee consisting of radiation oncologists' experts in prostate cancer was asked to answer a dedicated question-naire, including 41 questions on the main controversial issues with regard to oligometastatic prostate cancer.Results: The panel achieved consensus on patient selection and routine use of prostate-specific mem-brane antigen positron emission tomography (PSMA PET) imaging as preferred staging and restaging imaging. MDT strategies are recommended in the de novo oligometastatic, oligorecurrent and oligopro-gressive disease setting for nodal, bone and visceral metastases. Radiation therapy doses, volumes and techniques were discussed and commented.Conclusion: These recommendations have the purpose of providing standardization and consensus to optimize the radiotherapy treatment of oligometastatic prostate cancer until mature results of random-ized trials are available.AT would like to acknowledge the support of Cancer Research UK (C33589/A28284 and C7224/A28724) . This project represents independent research supported by the National Institute for Health research (NIHR) Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and the Institute of Cancer Research, London. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care
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