72 research outputs found

    High-resolution laser system for the S3-Low Energy Branch

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    In this paper we present the first high-resolution laser spectroscopy results obtained at the GISELE laser laboratory of the GANIL-SPIRAL2 facility, in preparation for the first experiments with the S3^3-Low Energy Branch. Studies of neutron-deficient radioactive isotopes of erbium and tin represent the first physics cases to be studied at S3^3. The measured isotope-shift and hyperfine structure data are presented for stable isotopes of these elements. The erbium isotopes were studied using the 4f126s24f^{12}6s^2 3H6→4f12(3H)6s6p^3H_6 \rightarrow 4f^{12}(^3 H)6s6p J=5J = 5 atomic transition (415 nm) and the tin isotopes were studied by the 5s25p2(3P0)→5s25p6s(3P1)5s^25p^2 (^3P_0) \rightarrow 5s^25p6s (^3P_1) atomic transition (286.4 nm), and are used as a benchmark of the laser setup. Additionally, the tin isotopes were studied by the 5s25p6s(3P1)→5s25p6p(3P2)5s^25p6s (^3P_1) \rightarrow 5s^25p6p (^3P_2) atomic transition (811.6 nm), for which new isotope-shift data was obtained and the corresponding field-shift F812F_{812} and mass-shift M812M_{812} factors are presented

    Determination of rapid Deccan eruptions across the Cretaceous-Tertiary boundary using paleomagnetic secular variation: 2. Constraints from analysis of eight new sections and synthesis for a 3500-m-thick composite section

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    International audienceThe present paper completes a restudy of the main lava pile in the Deccan flood basalt province (trap) of India. Chenet et al. (2008) reported results from the upper third, and this paper reports the lower two thirds of the 3500-m-thick composite section. The methods employed are the same, i.e., combined use of petrology, volcanology, chemostratigraphy, morphology, K-Ar absolute dating, study of sedimentary alteration horizons, and as the main correlation tool, analysis of detailed paleomagnetic remanence directions. The thickness and volume of the flood basalt province studied in this way are therefore tripled. A total of 169 sites from eight new sections are reported in this paper. Together with the results of Chenet et al. (2008), these data represent in total 70% of the 3500-m combined section of the main Deccan traps province. This lava pile was erupted in some 30 major eruptive periods or single eruptive events (SEE), each with volumes ranging from 1000 to 20,000 km 3 and 41 individual lava units with a typical volume of 1300 km 3. Paleomagnetic analysis shows that some SEEs with thicknesses attaining 200 m were emplaced over distances in excess of 100 km (both likely underestimates, due to outcrop conditions) and up to 800 km. The total time of emission of all combined SEEs could have been (much) less than 10 ka, with most of the time recorded in a very small number of intervening alteration levels marking periods of volcanic quiescence (so-called ''big red boles''). The number of boles, thickness of the pulses, and morphology of the traps suggest that eruptive fluxes and volumes were larger in the older formations and slowed down with more and longer quiescence periods in the end. On the basis of geochronologic results published by Chenet et al. (2007) and paleontological results from Keller et al. (2008), we propose that volcanism occurred in three rather short, discrete phases or megapulses, an early one at $67.5 ± 1 Ma near the C30r/C30n transition and the two largest around 65 ± 1 Ma, one entirely within C29r just before the K-T boundary, the other shortly afterward spanning the C29r/C29n reversal. We next estimate sulfur dioxide (likely a major agent of environmental stress) amounts and fluxes released by SEEs: they would have ranged from 5 to 100 Gt and 0.1 to 1 Gt/a, respectively, over durations possibly as short as 100 years for each SEE. The chemical input of the Chicxulub impact would have been on the same order as that of a very large single pulse. The impact, therefore, appears as important but incremental, neither the sole nor main cause of the Cretaceous-Tertiary mass extinctions

    DEB025 (Alisporivir) Inhibits Hepatitis C Virus Replication by Preventing a Cyclophilin A Induced Cis-Trans Isomerisation in Domain II of NS5A

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    DEB025/Debio 025 (Alisporivir) is a cyclophilin (Cyp)-binding molecule with potent anti-hepatitis C virus (HCV) activity both in vitro and in vivo. It is currently being evaluated in phase II clinical trials. DEB025 binds to CypA, a peptidyl-prolyl cis-trans isomerase which is a crucial cofactor for HCV replication. Here we report that it was very difficult to select resistant replicons (genotype 1b) to DEB025, requiring an average of 20 weeks (four independent experiments), compared to the typically <2 weeks with protease or polymerase inhibitors. This indicates a high genetic barrier to resistance for DEB025. Mutation D320E in NS5A was the only mutation consistently selected in the replicon genome. This mutation alone conferred a low-level (3.9-fold) resistance. Replacing the NS5A gene (but not the NS5B gene) from the wild type (WT) genome with the corresponding sequence from the DEB025res replicon resulted in transfer of resistance. Cross-resistance with cyclosporine A (CsA) was observed, whereas NS3 protease and NS5B polymerase inhibitors retained WT-activity against DEB025res replicons. Unlike WT, DEB025res replicon replicated efficiently in CypA knock down cells. However, DEB025 disrupted the interaction between CypA and NS5A regardless of whether the NS5A protein was derived from WT or DEB025res replicon. NMR titration experiments with peptides derived from the WT or the DEB025res domain II of NS5A corroborated this observation in a quantitative manner. Interestingly, comparative NMR studies on two 20-mer NS5A peptides that contain D320 or E320 revealed a shift in population between the major and minor conformers. These data suggest that D320E conferred low-level resistance to DEB025 probably by reducing the need for CypA-dependent isomerisation of NS5A. Prolonged DEB025 treatment and multiple genotypic changes may be necessary to generate significant resistance to DEB025, underlying the high barrier to resistance

    Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

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    Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≄1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≀6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Establishment of an in vivo model for molecular assessment of titanium implant osseointegration in compromised bone

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    Shortening of the healing time before loading risks impeding successful titanium implant anchorage into compromised bone. A thorough understanding at the genetic scale of the early phases of bone regeneration at the implant interface is required before the development of strategies to enhance implant osseointegration. In this study a new in vivo implant model to explore the mechanism by which titanium implant osseointegration is affected by the host bone properties is presented. An implant was conceptualized enabling standardized harvesting of peri-implant tissue for quantitative molecular analysis while preserving the mimicking of the clinical setting. The implant is partly indented to provide a well-defined healing compartment from where tissue differentiation and de novo bone formation can be investigated and partly screw-threaded to provide a good implant anchorage into the bone. The feasibility of the implant design was assessed in osteopenic bone conditions, evoked by simulated weightlessness. Wistar rats were either hindlimb unloaded by tail suspension (HU) for 9 days or acted as controls (CTL). The status of compromised bone tissue through 9-days HU was confirmed by micro-X-ray computed tomography. The implant was installed in the proximal tibial bone 7 days after the onset of HU or CTL. Two days postimplantation, the peri-implant regenerating tissue responses were recorded by measuring expression of inflammatory, angiogenic, and bone resorption parameters (hypoxia-inducible factor 1, alpha subunit; vascular endothelial growth factor A; angiopoietin 1; endothelial PAS domain protein 1; fibroblast growth factor 2; tumor necrosis factor; interleukin 11; acid phosphatase 5, tartrate resistant; tumor necrosis factor (ligand) superfamily, member 11/RANKL). We successfully demonstrated that HU-associated bone conditions evoked a significant alteration of expression of the angiogenic markers in the peri-implant regenerative tissue during initial implant osseointegration, whereas the expression levels of the inflammatory and bone resorption parameters remained unchanged. We concluded that this in vivo implant model provides a well-designed and controlled method to examine molecular responses in implant osseointegration to impaired bone conditions. This model may serve to explore the application of anabolic strategies in peri-implant osteogenesis.status: publishe

    In vivo molecular evidence of delayed titanium implant osseointegration in compromised bone

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    Optimization of implant osseointegration in patients with reduced bone healing potential is a challenge remaining in implant dentistry. Identification of the genes that are modulated during implant osseointegration in normal versus osteopenic bone is needed to successfully address these pertinent clinical needs. The present study aimed to assess the initial and early molecular events following titanium implant installation in normal and compromised bone in a rat tibia model. Peri-implant tissue from a well-defined tissue regeneration compartment was analyzed at 2 and 7 days post-surgery for the expression of select markers of inflammation, angiogenesis, bone resorption and bone formation. Impaired bone was induced by hindlimb unloading and validated using ÎŒCT. The essential step of angiogenesis preceding bone regeneration was evidenced for the peri-implant setting in healthy bone. Compromised bone significantly affected the angiogenesis-osteogenesis coupling in the initial phase (2 days post-surgery), with altered expressions of Vegfa and Epas1 coinciding with downregulated expressions of Col1a1, Bmp2, Bmp4, Alpl and Bglap. At 7 days post-implantation, differences between normal and compromised peri-implant bone were no longer observed. This in vivo molecular evidence of delayed implant osseointegration in compromised bone reassert modern strategies in implant development, such as surface modifications and bioengineered approaches, to improve implant osseointegration in compromised conditions.status: publishe

    Complete genome sequence, taxonomic assignment, and comparative analysis of the untranslated regions of the Modoc virus, a flavivirus with no known vector

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    We recently developed a model for flavivirus infection in mice and hamsters using the Modoc virus (MODV), a flavivirus with no known vector (P. Leyssen, A. Van Lommel, C. Drosten, H. Schmitz, E. De Clercq, and J. Neyts, 2001, Virology 279, 27-37). We now present the coding and noncoding sequence of MODV. The Modoc virus genome was determined to be 10,600 nucleotides in length with a single open reading frame extending from nucleotides 110 to 10,234, encoding 3374 amino acids. The deduced gene order of the single open reading frame is C-prM-E-NS1-NS2A-NS2B-NS3-NS4A-NS4B-NS5, which is exactly the same as that of the mosquito- and tick-borne flaviviruses. It is flanked by a 5'- and 3'-untranslated region (UTR) of 109 and 366 nucleotides, respectively. Alignment of the MODV amino acid sequence with that of 20 other flaviviruses revealed several regions with high sequence similarity corresponding to functionally important domains (e.g., the serine protease/helicase/NTPase of NS3 and the methyltransferase/RNA-dependent RNA polymerase of NS5) and conserved sites for proteolytic cleavage by viral and cellular proteases. Phylogenetic analysis of the entire coding region confirmed the classification of MODV within the flaviviruses with no known vector, which is in agreement with previous findings based on partial NS5 sequences. A detailed comparative analysis of the putative folding patterns of the 5'- and 3'-UTR of MODV and of the tick- and mosquito-borne viruses was carried out. Structural elements in the 5'- and 3' UTR of MODV that are preserved among vector-borne flaviviruses were noted and so were structural elements distinguishing the MODV UTRs from mosquito-borne and tick-borne flaviviruses. Also the putative secondary structure of circularized MODV RNA is presented.status: publishe
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