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Institution

University of Rennes

EducationRennes, France
About: University of Rennes is a education organization based out in Rennes, France. It is known for research contribution in the topics: Population & Crystal structure. The organization has 18404 authors who have published 40374 publications receiving 995327 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors reported femtosecond time-resolved X-ray absorption near-edge spectroscopy (XANES) measurements of a spin-crossover system, iron(II) tris(2,2′-bipyridine) in water.
Abstract: X-ray free electron lasers (XFELs) deliver short (<100 fs) and intense (∼1012 photons) pulses of hard X-rays, making them excellent sources for time-resolved studies. Here we show that, despite the inherent instabilities of current (SASE based) XFELs, they can be used for measuring high-quality X-ray absorption data and we report femtosecond time-resolved X-ray absorption near-edge spectroscopy (XANES) measurements of a spin-crossover system, iron(II) tris(2,2′-bipyridine) in water. The data indicate that the low-spin to high-spin transition can be modeled by single-exponential kinetics convoluted with the overall time resolution. The resulting time constant is ∼160 fs.

167 citations

Journal ArticleDOI
TL;DR: In this paper, the authors apply this technique in addition to (U-Th)/He thermochronology on detrital zircons to assess peak metamorphic temperatures (T) and the late exhumational history respectively, along different transects in central and southern Taiwan.
Abstract: The Taiwan mountain belt is composed of a Cenozoic slate belt (Hsuehshan Range units, HR, and Backbone Slates, BS) and of accreted polymetamorphic basement rocks (Tananao Complex, TC). Ongoing crustal shortening has resulted from the collision between the Chinese continental margin and the Luzon volcanic arc, which initiated ~6.5 Ma ago. The grade and age of metamorphism and exhumation are a key record of the development of the orogenic wedge. Because the Taiwan mountain belt is mostly composed by accreted sediments lacking metamorphic index minerals, quantitative constraints on metamorphism are sparse. By contrast, these rocks are rich in carbonaceaous material (CM) and are therefore particularly appropriate for RSCM (Raman Spectroscopy of CM) thermometry. We apply this technique in addition to (U-Th)/He thermochronology on detrital zircons to assess peak metamorphic temperatures (T) and the late exhumational history respectively, along different transects in central and southern Taiwan. In the case of the HR units, we find evidence for high metamorphic T of at least 340°–350°C and locally up to 475°C, and for relative rapid exhumation with zircon (U-Th)/He ages in the range of 1.5–2 Ma. Farther east, the BS were only slightly metamorphosed (T < 330 °C), and zircons are not reset for (U-Th)/He. From the eastern BS to the inner TC schists, T gradually increases from ~350°C up to ~500°C following an inverted metamorphic gradient. Available geochronological constraints and the continuous thermal gradient from the BS to the basement rocks of the TC suggest that the high RSCM T of the TC were most probably acquired during the last orogeny, and were not inherited from a previous thermal event. Zircons yield (U-Th)/He ages of ~0.5–1.2 Ma. Peak metamorphic T and the timing of exhumation do not show along-strike variations over the TC in the studied area. In contrast, exhumation is laterally diachronous and decreases southward in the case of the HR units. In particular, our data imply that the HR units have been exhumed by a minimum of 15 km over the last few Ma. In the case of the BS, they show far less cumulated exhumation and much slower cooling rates. We propose that most of the deformation and exhumation of the Taiwan mountain belt is sustained through two underplating windows located beneath the Hsuehshan Range and the TC. Our data show significant departures from the predictions of the prevailing model in Taiwan, which assumes a homogeneous critical wedge with dominant frontal accretion. Our study sheds new light on how the mountain belt has grown as a possible result of underplating mostly.

167 citations

Journal ArticleDOI
TL;DR: It is shown that Aurora‐A increases at the G2–M transistion and disappears completely at G1 in XL2 cells, and is the first protein, at least in the assay system, that undergoes a D‐Box‐dependent degradation mediated by APC/Fizzy‐Related but not byAPC/fizzy.
Abstract: Aurora-A kinase is a mitotic spindle-pole-associated protein that has been implicated in duplication and separation of centrosomes and in spindle assembly. The proper timing and amplitude of Aurora-A expression seems to be important, as elevated levels of this protein have been associated with centrosome abnormalities and aneuploidy in mammalian cells. We show that Aurora-A increases at the G2-M transistion and disappears completely at G1 in XL2 cells. Using Xenopus oocyte extracts, we demonstrate that degradation of Aurora-A is mediated by the anaphase-promoting complex (APC) and is regulated by Fizzy-Related but not by Fizzy. Degradation of Aurora-A depends on a D-Box, but not on its KEN-Box motif, as mutation of its C-terminal D-Box sequence induces stabilization of the protein. Accordingly, addition into the extracts of a cyclin B-type D-Box-motif-containing peptide completely suppresses its degradation. Furthermore, APC/Fizzy-Related ubiquitylates the wild type but not a D-Box mutant form of Aurora-A in vitro. Consistent with these data, ectopic expression of Fizzy-Related in Xenopus oocytes induces complete degradation of endogenous Aurora-A. Aurora-A is thus the first protein, at least in our assay system, that undergoes a D-Box-dependent degradation mediated by APC/Fizzy-Related but not by APC/Fizzy.

166 citations

Journal ArticleDOI
TL;DR: An extension of the MUSIC method to an arbitrary even order 2q (qges1), giving rise to the 2q-MUSIC methods, which show off new important results for direction-finding applications and in particular the best performances of 2-M USIC and 4-M MUSIC methods with q>2, despite their higher variance, when some resolution is required.
Abstract: From the beginning of the 1980s, many second-order (SO) high-resolution direction-finding methods, such as the MUSIC method (or 2-MUSIC), have been developed mainly to process efficiently the multisource environments. Despite of their great interests, these methods suffer from serious drawbacks such as a weak robustness to both modeling errors and the presence of a strong colored background noise whose spatial coherence is unknown, poor performance in the presence of several poorly angularly separated sources from a limited duration observation and a maximum of N-1 sources to be processed from an array of N sensors. Mainly to overcome these limitations and in particular to increase both the resolution and the number of sources to be processed from an array of N sensors, fourth-order (FO) high-resolution direction-finding methods have been developed, from the end of the 1980s, to process non-Gaussian sources, omnipresent in radio communications, among which the 4-MUSIC method is the most popular. To increase even more the resolution, the robustness to modeling errors, and the number of sources to be processed from a given array of sensors, and thus to minimize the number of sensors in operational contexts, we propose in this paper an extension of the MUSIC method to an arbitrary even order 2q (qges1), giving rise to the 2q-MUSIC methods. The performance analysis of these new methods show off new important results for direction-finding applications and in particular the best performances, with respect to 2-MUSIC and 4-MUSIC, of 2q-MUSIC methods with q>2, despite their higher variance, when some resolution is required

166 citations

Journal ArticleDOI
TL;DR: Losartan was able to decrease blood pressure in patients with MFS but not to limit aortic dilatation during a 3-year period in patients >10 years old, and β-Blocker therapy alone should remain the standard first line therapy in these patients.
Abstract: AIMS: To evaluate the benefit of adding Losartan to baseline therapy in patients with Marfan syndrome (MFS). METHODS AND RESULTS: A double-blind, randomized, multi-centre, placebo-controlled, add on trial comparing Losartan (50 mg when \textless50 kg, 100 mg otherwise) vs. placebo in patients with MFS according to Ghent criteria, age \textgreater10 years old, and receiving standard therapy. 303 patients, mean age 29.9 years old, were randomized. The two groups were similar at baseline, 86% receiving β-blocker therapy. The median follow-up was 3.5 years. The evolution of aortic diameter at the level of the sinuses of Valsalva was not modified by the adjunction of Losartan, with a mean increase in aortic diameter at the level of the sinuses of Valsalva of 0.44 mm/year (s.e. = 0.07) (-0.043 z/year, s.e. = 0.04) in patients receiving Losartan and 0.51 mm/year (s.e. = 0.06) (-0.01 z/year, s.e. = 0.03) in those receiving placebo (P = 0.36 for the comparison on slopes in millimeter per year and P = 0.69 for the comparison on slopes on z-scores). Patients receiving Losartan had a slight but significant decrease in systolic and diastolic blood pressure throughout the study (5 mmHg). During the study period, aortic surgery was performed in 28 patients (15 Losartan, 13 placebo), death occurred in 3 patients [0 Losartan, 3 placebo, sudden death (1) suicide (1) oesophagus cancer (1)]. CONCLUSION: Losartan was able to decrease blood pressure in patients with MFS but not to limit aortic dilatation during a 3-year period in patients \textgreater10 years old. β-Blocker therapy alone should therefore remain the standard first line therapy in these patients

166 citations


Authors

Showing all 18470 results

NameH-indexPapersCitations
Philippe Froguel166820118816
Bart Staels15282486638
Yi Yang143245692268
Geoffrey Burnstock141148899525
Shahrokh F. Shariat118163758900
Lutz Ackermann11666945066
Douglas R. MacFarlane11086454236
Elliott H. Lieb10751257920
Fu-Yuan Wu10736742039
Didier Sornette104129544157
Stefan Hild10345268228
Pierre I. Karakiewicz101120740072
Philippe Dubois101109848086
François Bondu10044069284
Jean-Michel Savéant9851733518
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202321
2022176
20212,655
20202,735
20192,670
20182,378