Four-Formation In-Track Configuration Maintenance Strategy

The aim of this paper is to present the analysis conducted by CNES for the maintenance of a formation made of several LEO satellites (typically 4) in several planes (typically 2), 100 km or so apart from each other. The along-track separations between the satellites have to be controlled to within 15 km thanks to orbit correction maneuvers supposed to be performed every 2 weeks. The main difficulty is related to solar activity which is expected to be close to its maximum for the entire mission s lifespan. As a matter of fact, a high solar activity makes orbit prediction harder, and makes it impossible to keep the altitude of the formation constant. Thus, a specific relative maintenance strategy had to be devised in order to meet the mission's requirements. The first part provides a few elements on the mission analysis process that has taken place. The method used for the evaluation of the maneuver frequency is detailed, based on the evaluation of the effects of atmospheric drag on the orbit. The second part is dedicated to the maintenance strategy that has been designed, and particularly to the computation of the reference orbits and of the velocity increments that enable the in-track inter-satellite distances to be maintained within the desired bounds. Finally a few simulation results are presented; they enable the performance of the maintenance strategy to be checked in a more realistic context

Pigeon circovirus: baculovirus expression of the capsid protein gene, specific antibody and viral load measured by real time polymerase chain reaction

peer reviewe

Impaired Interleukin-1β and c-Fos Expression in the Hippocampus Is Associated with a Spatial Memory Deficit in P2X7 Receptor-Deficient Mice

Recent evidence suggests that interleukin-1β (IL-1β), which was originally identified as a proinflammatory cytokine, is also required in the brain for memory processes. We have previously shown that IL-1β synthesis in the hippocampus is dependent on P2X7 receptor (P2X7R), which is an ionotropic receptor of ATP. To substantiate the role of P2X7R in both brain IL-1β expression and memory processes, we examined the induction of IL-1β mRNA expression in the hippocampus of wild-type (WT) and homozygous P2X7 receptor knockout mice (P2X7R−/−) following a spatial memory task. The spatial recognition task induced both IL-1β mRNA expression and c-Fos protein activation in the hippocampus of WT but not of P2X7R−/− mice. Remarkably, P2X7R−/− mice displayed spatial memory impairment in a hippocampal-dependant task, while their performances in an object recognition task were unaltered. Taken together, our results show that P2X7R plays a critical role in spatial memory processes and the associated hippocampal IL-1β mRNA synthesis and c-Fos activation

Advanced Neuroimaging with Computed Tomography Scanning

International audienceThe x-ray computed tomography (CT) is well known as a useful imaging method and thus CT images have continuingly been used for many applications, especially in medical fields. This book discloses recent advances and new ideas in theories and applications for CT imaging and its analysis. The 16 chapters selected in this book cover not only the major topics of CT imaging and analysis in medical fields, but also some advanced applications for forensic and industrial purposes. These chapters propose state-of-the-art approaches and cutting-edge research results

Distinct spatiotemporal patterns and PARP dependence of XRCC1 recruitment to single-strand break and base excision repair

Single-strand break repair (SSBR) and base excision repair (BER) of modified bases and abasic sites share several players. Among them is XRCC1, an essential scaffold protein with no enzymatic activity, required for the coordination of both pathways. XRCC1 is recruited to SSBR by PARP-1, responsible for the initial recognition of the break. The recruitment of XRCC1 to BER is still poorly understood. Here we show by using both local and global induction of oxidative DNA base damage that XRCC1 participation in BER complexes can be distinguished from that in SSBR by several criteria. We show first that XRCC1 recruitment to BER is independent of PARP. Second, unlike SSBR complexes that are assembled within minutes after global damage induction, XRCC1 is detected later in BER patches, with kinetics consistent with the repair of oxidized bases. Third, while XRCC1-containing foci associated with SSBR are formed both in eu- and heterochromatin domains, BER complexes are assembled in patches that are essentially excluded from heterochromatin and where the oxidized bases are detected

Chemotherapy of advanced small-bowel adenocarcinoma: a multicenter AGEO study

Les adénocarcinomes de l’intestin grêle (AIG) sont des tumeurs rares et de mauvais pronostic à un stade avancé. Les données publiées concernant l’efficacité de la chimiothérapie palliative sont peu nombreuses. Le but de notre étude était d’évaluer l’efficacité et la tolérance de différents protocoles « modernes » de chimiothérapie et de comparer l’efficacité des chimiothérapies à base de sels de platine dans le traitement de première ligne des AIG avancés. Cette étude rétrospective multicentrique a inclus 93 patients (sexe masculin : 53 % ; âge médian : 56 ans ; site primitif duodénal : 53 %) avec un AIG avancé (métastatique : 86 %) traités par LV5FU2 (n = 10), FOLFOX (n = 48), FOLFIRI (n = 19) ou LV5FU2- cisplatine (n = 16). Le taux de toxicité grade 3-4 était significativement plus fréquent dans le groupe de patients traités par LV5FU2-cisplatine (75 %) comparativement aux autres groupes de patients (p = 0,001). Les médianes de survie sans progression (SSP) étaient de 7,7 ; 6,9 ; 6,0 et 4,8 mois (p = 0,16) et les médianes de survie globale (SG) étaient de 13,5 ; 17,8 ; 10,6 et 9,3 mois (p = 0,25) pour les quatre groupes de patients traités par LV5FU2, FOLFOX, FOLFIRI et LV5FU2-cisplatine, respectivement. En analyse multivariée, l’indice de performance OMS à 2 (p < 0,0001) ainsi que des taux élevés d’ACE (p = 0,02) et de CA 19-9 (p = 0,03) avant traitement étaient les seuls facteurs indépendants significativement associés à un mauvais pronostic. Dans le sous-groupe de patients traités par sels de platine, ceux qui ont reçu une chimiothérapie par FOLFOX avaient de meilleures SSP et SG que les patients traités par LV5FU2-cisplatine. En analyse multivariée, le traitement par FOLFOX était un facteur significatif et indépendant de survie prolongée en termes de SSP (p < 0,0001) et SG (p = 0,02). Ainsi, cette étude, la plus grande rapportée à ce jour, suggère d’une part que l’indice de performance OMS et les taux d’ACE et CA 19-9 avant traitement sont des facteurs pronostiques indépendants de survie et, d’autre part que la chimiothérapie par FOLFOX est le traitement de choix en première ligne des AIG avancés

KRAS Mutation Detection in Paired Frozen and Formalin-Fixed Paraffin-Embedded (FFPE) Colorectal Cancer Tissues

KRAS mutation has been unambiguously identified as a marker of resistance to cetuximab-based treatment in metastatic colorectal cancer (mCRC) patients. However, most studies of KRAS mutation analysis have been performed using homogenously archived CRC specimens, and studies that compare freshly frozen specimens and formalin-fixed paraffin-embedded (FFPE) specimens of CRC are lacking. The aim of the present study was to evaluate the impact of tissue preservation on the determination of KRAS mutational status. A series of 131 mCRC fresh-frozen tissues were first analyzed using both high-resolution melting (HRM) and direct sequencing. KRAS mutations were found in 47/131 (35.8%) using both approaches. Out of the 47 samples that were positive for KRAS mutations, 33 had available matched FFPE specimens. Using HRM, 2/33 (6%) demonstrated suboptimal template amplification, and 2/33 (6%) expressed an erroneous wild-type KRAS profile. Using direct sequencing, 6/33 (18.1%) displayed a wild-type KRAS status, and 3/33 (9.1%) showed discordant mutations. Finally, the detection of KRAS mutations was lower among the FFPE samples compared with the freshly frozen samples, demonstrating that tissue processing clearly impacts the accuracy of KRAS genotyping

Growth factors in multiple myeloma: a comprehensive analysis of their expression in tumor cells and bone marrow environment using Affymetrix microarrays

<p>Abstract</p> <p>Background</p> <p>Multiple myeloma (MM) is characterized by a strong dependence of the tumor cells on their microenvironment, which produces growth factors supporting survival and proliferation of myeloma cells (MMC). In the past few years, many myeloma growth factors (MGF) have been described in the literature. However, their relative importance and the nature of the cells producing MGF remain unidentified for many of them.</p> <p>Methods</p> <p>We have analysed the expression of 51 MGF and 36 MGF receptors (MGFR) using Affymetrix microarrays throughout normal plasma cell differentiation, in MMC and in cells from the bone marrow (BM) microenvironment (CD14, CD3, polymorphonuclear neutrophils, stromal cells and osteoclasts).</p> <p>Results</p> <p>4/51 MGF and 9/36 MGF-receptors genes were significantly overexpressed in plasmablasts (PPC) and BM plasma cell (BMPC) compared to B cells whereas 11 MGF and 11 MGFR genes were overexpressed in BMPC compared to PPC. 3 MGF genes (AREG, NRG3, Wnt5A) and none of the receptors were significantly overexpressed in MMC versus BMPC. Furthermore, 3/51 MGF genes were overexpressed in MMC compared to the the BM microenvironment whereas 22/51 MGF genes were overexpressed in one environment subpopulation compared to MMC.</p> <p>Conclusions</p> <p>Two major messages arise from this analysis 1) The majority of MGF genes is expressed by the bone marrow environment. 2) Several MGF and their receptors are overexpressed throughout normal plasma cell differentiation. This study provides an extensive and comparative analysis of MGF expression in plasma cell differentiation and in MM and gives new insights in the understanding of intercellular communication signals in MM.</p

Evaluation de l’impact du stress hydrique et de la culture inter-rang sur la physiologie des lavandes et des lavandins cultivés

Les cultures françaises de Lavande et Lavandin subissent un sévère déclin depuis une vingtaine d’années, résultant de l’effet combiné de la maladie du dépérissement à phytoplasme et de sécheresses intenses et répétitives. Face à ce défi, l’amélioration de la résistance des lavanderaies est nécessaire grâce à des pratiques agro-écologiques telle que l’implantation de couverts végétaux en inter-rang. Ce type de culture serait un moyen efficace contre le vecteur de la maladie et présente d’autres avantages comme la gestion des adventices ou la lutte contre l’érosion des sols. Nos objectifs sont i) d’évaluer l’impact de la culture inter-rang sur la physiologie de la lavande et ii) de développer des outils et indicateurs qui permettent de caractériser l’état de la plante en situation de sécheresse en champ. Le PépiPIAF est un outil innovant, autonome et connectable qui est basé sur la mesure des variations de diamètre d’une tige et permet de suivre en continue la dynamique de croissance, la phénologie et l’état physiologique des plants en temps réel. Différents couverts végétaux ont été mis en place dans des parcelles expérimentales afin de tester leurs effets sur la physiologie des plants. Après une étape de développement de l’outil en serre (sécheresse contrôlée), les PépiPIAFs ont été installés dans ces parcelles pour deux ans. Ils permettent de diagnostiquer en continu l’état physiologique des plants, en particulier sous conditions de stress hydrique et de comparer l’impact des couverts végétaux. En parallèle, d’autres paramètres écophysiologiques liés aux propriétés hydrique et hydraulique sont suivis