À propos de l’exposition Upside Down – Les Arctiques

The exhibit Upside Down - Les Arctiques—at the gallery Jardin du musée du quai Branly (Paris, France) from September 30, 2008 to January 11, 2009—presents about 500 artefacts from Inuit cultures expected to stimulate the imagination of the public. Under the cover of a sensorial walk into the polar world through an ingenious scenery hides an underlying agenda: the valorisation of a private collection and his collector.L’exposition Upside Down - Les Arctiques —installée dans la galerie Jardin du musée du quai Branly (Paris, France) du 30 septembre 2008 au 11 janvier 2009— présente près de 500 artefacts de la culture inuit censés stimuler l’imaginaire du public. Sous couvert d’une promenade sensorielle dans le monde polaire, via une scénographie remarquée, se profile une attention sous-jacente: la valorisation d’une collection privée et de son auteur

Quantum Coherence at Low Temperatures in Mesoscopic Systems: Effect of Disorder

We study the disorder dependence of the phase coherence time of quasi one-dimensional wires and two-dimensional (2D) Hall bars fabricated from a high mobility GaAs/AlGaAs heterostructure. Using an original ion implantation technique, we can tune the intrinsic disorder felt by the 2D electron gas and continuously vary the system from the semi-ballistic regime to the localized one. In the diffusive regime, the phase coherence time follows a power law as a function of diffusion coefficient as expected in the Fermi liquid theory, without any sign of low temperature saturation. Surprisingly, in the semi-ballistic regime, it becomes independent of the diffusion coefficient. In the strongly localized regime we find a diverging phase coherence time with decreasing temperature, however, with a smaller exponent compared to the weakly localized regime.Comment: 21 pages, 30 figure

0232 : Small, medium but not large arteries are involved in digital ulcers associated with systemic sclerosis

BackgroundDigital ulcers (DU) are a burden in systemic sclerosis (SSc). Microangiopathy is a cardinal feature of SSc that plays a critical role in the development of DU. However, whether injury of medium or large vessels also contributes to DU in SSc is unknown.MethodsTo measure concomitantly in SSc patients with and without active DU i) the Augmentation Index of the reflected wave (Aix_75) by radial applanation tonometry, an index of small and medium arterial function, II) the aortic pulse wave velocity (PWV), a marker of large vessel injury (aortic stiffness).Results63 consecutive SSc patients were included (49 females, aged 57±12 years, disease duration 9.7±7.1 years), including 10 (15.9%) with active DU.Patients with active DU versus those without had increased Aix_75 (35% [28-38] versus 28% [20-34], p=0.041) whereas no difference existed in PWV (7,0m/s [6.7-10.1] versus 7,6m/s [6.8-8.7], p=0.887), in systolic, diastolic, as well as aortic pulse pressure (p=0.126, 0.592, and 0.161 respectively).By multivariate analysis, DU remained independently associated with Aix_75 (p=0.020).Using Aix_75 as a longitudinal variable, and when compared to patients in the low tertile, patients having Aix_75 in the highest tertile had ten-fold more DU (OR=10.23; 95% CI 1.12 to 93.34, p=0.039).ConclusionThe presence of DU is independently associated with Aix_75 whereas there is no relation with PWV. These data suggest that small and medium arteries are involved in the occurrence of DU whether large vessel stiffness does not contribute. Whether Aix_75 is predictive of further DU remained to be studied

Identification of Spectral Modifications Occurring during Reprogramming of Somatic Cells

Recent technological advances in cell reprogramming by generation of induced pluripotent stem cells (iPSC) offer major perspectives in disease modelling and future hopes for providing novel stem cells sources in regenerative medicine. However, research on iPSC still requires refining the criteria of the pluripotency stage of these cells and exploration of their equivalent functionality to human embryonic stem cells (ESC). We report here on the use of infrared microspectroscopy to follow the spectral modification of somatic cells during the reprogramming process. We show that induced pluripotent stem cells (iPSC) adopt a chemical composition leading to a spectral signature indistinguishable from that of embryonic stem cells (ESC) and entirely different from that of the original somatic cells. Similarly, this technique allows a distinction to be made between partially and fully reprogrammed cells. We conclude that infrared microspectroscopy signature is a novel methodology to evaluate induced pluripotency and can be added to the tests currently used for this purpose

Viral sequence variation in chronic carriers of hepatitis C virus has a low impact on liver steatosis.: HCV variability and steatosis

International audienceMost clinical studies suggest that the prevalence and severity of liver steatosis are higher in patients infected with hepatitis C virus (HCV) genotype 3 than in patients infected with other genotypes. This may reflect the diversity and specific intrinsic properties of genotype 3 virus proteins. We analyzed the possible association of particular residues of the HCV core and NS5A proteins known to dysregulate lipid metabolism with steatosis severity in the livers of patients chronically infected with HCV. We used transmission electron microscopy to quantify liver steatosis precisely in a group of 27 patients, 12 of whom were infected with a genotype 3 virus, the other 15 being infected with viruses of other genotypes. We determined the area covered by lipid droplets in liver tissues and analyzed the diversity of the core and NS5A regions encoded by the viral variants circulating in these patients. The area covered by lipid droplets did not differ significantly between patients infected with genotype 3 viruses and those infected with other genotypes. The core and NS5A protein sequences of the viral variants circulating in patients with mild or severe steatosis were evenly distributed throughout the phylogenic trees established from all the collected sequences. Thus, individual host factors seem to play a much greater role than viral factors in the development of severe steatosis in patients chronically infected with HCV, including those infected with genotype 3 viruses

Body mass index influences the response to infliximab in ankylosing spondylitis

INTRODUCTION: The excess of adipose tissue in obese individuals may have immunomodulating properties and pharmacokinetic consequences. The aim of this study was to determine whether body mass index (BMI) affects response to infliximab (IFX) in ankylosing spondylitis (AS) patients. METHODS: In 155 patients retrospectively included with active AS, the BMI was calculated before initiation of IFX treatment (5 mg/kg intravenously). After 6 months of treatment, changes from baseline in BASDAI, Visual Analogue Scale (VAS) pain, C-reactive protein (CRP) level, and total dose of nonsteroidal antiinflammatory drug (NSAID) were dichotomized with a threshold corresponding to a decrease of 50% of initial level of the measure, into binary variables assessing response to IFX (BASDAI50, VAS50, CRP50, NSAID50). Whether the BMI was predictive of the response to IFX therapy according to these definitions was assessed with logistic regression. RESULTS: Multivariate analysis found that a higher BMI was associated with a lower response for BASDAI50 (P = 0.0003; OR, 0.87; 95% CI (0.81 to 0.94)), VAS50 (P < 0.0001; OR, 0.87; 95% CI (0.80 to 0.93)); CRP50 (P = 0.0279; OR, 0.93; 95% CI (0.88 to 0.99)), and NSAID50 (P = 0.0077; OR, 0.91; 95% CI (0.85 to 0.97)), criteria. According to the three WHO BMI categories, similar results were found for BASDAI50 (77.6%, 48.9%, and 26.5%; P < 0.0001), VAS50 (72.6%, 40.4%, and 16.7%; P < 0.0001); CRP50 (87.5%, 65.7%, and 38.5%; P = 0.0001), and NSAID50 (63.2%, 51.5%, and 34.6%; P = 0.06). CONCLUSIONS: This study provides the first evidence that a high BMI negatively influences the response to IFX in AS. Further prospective studies, including assessment of the fat mass, pharmacokinetics, and adipokines dosages are mandatory to elucidate the role of obesity in AS IFX response

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Germ Cell-Specific Targeting of DICER or DGCR8 Reveals a Novel Role for Endo-siRNAs in the Progression of Mammalian Spermatogenesis and Male Fertility

Small non-coding RNAs act as critical regulators of gene expression and are essential for male germ cell development and spermatogenesis. Previously, we showed that germ cell-specific inactivation of Dicer1, an endonuclease essential for the biogenesis of micro-RNAs (miRNAs) and endogenous small interfering RNAs (endo-siRNAs), led to complete male infertility due to alterations in meiotic progression, increased spermatocyte apoptosis and defects in the maturation of spermatozoa. To dissect the distinct physiological roles of miRNAs and endo-siRNAs in spermatogenesis, we compared the testicular phenotype of mice with Dicer1 or Dgcr8 depletion in male germ cells. Dgcr8 mutant mice, which have a defective miRNA pathway while retaining an intact endo-siRNA pathway, were also infertile and displayed similar defects, although less severe, to Dicer1 mutant mice. These included cumulative defects in meiotic and haploid phases of spermatogenesis, resulting in oligo-, terato-, and azoospermia. In addition, we found by RNA sequencing of purified spermatocytes that inactivation of Dicer1 and the resulting absence of miRNAs affected the fine tuning of protein-coding gene expression by increasing low level gene expression. Overall, these results emphasize the essential role of miRNAs in the progression of spermatogenesis, but also indicate a role for endo-siRNAs in this process

Les premières mesures de protection des sites autochtones aux États-Unis et au Canada : pillage et circulation des biens

The enactment of federal laws concerning archaeology in the United States and Canada came as a response to the looting of ancient native sites in both countries. While this article investigates who the looters were and what their motives could be, it also aims to provide insights into the various concerns the laws addressed, especially by comparing the management of the collections of Native artefacts held by the Canadian and American national museums

L'optimisation topologique et la fabrication additive, amélioration de la chaine de conception

peer reviewedL'intérêt de combiner l'optimisation topologique avec les méthodes de fabrication additive vient du fait que d'une part, l'optimisation topologique permet de générer des géométries complexes que les procédés d'usinage conventionnels ne sont pas capables de réaliser et que, d'autre part, la fabrication additive permet de réaliser des formes complexes telles que des cavités emprisonnées dans un volume ou des canaux non rectilignes, impossibles à reproduire en fonderie ou par usinage. De plus et contrairement aux techniques traditionnelles, la réalisation des géométries complexes n'influence pas le coût pour les techniques additives. Pour ces techniques, le coût est lié principalement au volume de la pièce. La complexité de la pièce n'est plus un problème mais un atout. Toutefois cette combinaison n'est pas encore exploitable au niveau industriel. En effet, les résultats fournis par l'optimisation topologique doivent être modifiés, souvent manuellement, pour les rendre utilisables par les méthodes de fabrication additive. Et ces modifications coûtent cher. Il est donc intéressant de limiter ou au mieux d'éliminer les étapes manuelles de la chaîne de conception. Ce papier propose une chaîne de conception optimisée pour une pièce devant être fabriquée par les méthodes additives. En outre, la prise en compte des contraintes inhérentes aux procédés de fabrication par addition de matière reste problématique. Une démarche simplifiée est proposée pour identifier les types de contraintes inhérentes aux procédés de fabrication par addition de matière, les quantifier pour certaines techniques et les intégrer dans le code d'optimisation topologique. La nouvelle chaine de conception minimise les interventions du concepteur qui rendent le processus plus lourd et moins viable industriellement. Dans cette nouvelle chaîne de conception, certaines étapes sont réalisées plus rapidement et génèrent de meilleurs résultats