Sternal reentry in a patient with previous deep sternal wound infection managed with horizontal titanium plate fixation

Redo open-heart surgery and sternal reentry in patients with previous deep sternal wound infection (DSWI) and absence of sternal integrity can be a delicate and morbid task due the lack of a dissection plane between the heart and the surrounding soft tissues. Delayed sternal reconstruction and osteosynthesis with horizontal titanium plating fixation (Synthes) following vacuum assisted therapy (KCI) has recently been proposed and adopted for the treatment of DSWI. We present such a case of a patient who was successfully reoperated for valve replacement three years after coronary artery bypass grafting complicated by DSWI and initially treated with titanium plate fixation

Alkaline-earth metal and rare-earth element incorporation control by ionic radius and growth rate on a stalagmite from the Chauvet Cave, Southeastern France

International audienc

Identification of sources and distribution of radiocarbon in the vicinity of La Hague nuclear reprocessing plant

International audienceThe terrestrial environment in the vicinity of La Hague nuclear reprocessing plant (COGEMA) is potentially influenced by two sources (atmospheric and marine) and by three ways of radionuclides transfer: 1) atmospheric fallout from old nuclear bombs experiments, 2) atmospheric fallout from gaseous throwing out from the reprocessing plant 3) marine aerosol and degassing (sea to land transfer) bearing radionuclides originating from liquid waste from the plant. Institute for Protection and Nuclear Safety (IPSN) has organised since 1997, with the collaboration of the Groupe d'Etudes Atomiques (GEA) de la Marine Nationale and the Laboratoire des Sciences du Climat et de l'Environnement (LSCE/CEA-CNRS), studies to identify radionuclides sources (atmospheric and marine) and to provide an evaluation of the radiocarbon around La Hague nuclear reprocessing plant and to follow the concentration evolution versus time. A sampling strategy has been established to provide a map of the distribution of radio-elements around the reprocessing plant and to identify the mode of transfers, to determine the deposition rates on soil and vegetation in order to precise the transfer model of radio-element in plants. Three experiments in terrestrial environment with sampling of a bioindicator like furze has done in 1997, 1998 and 1999. In 2000, during TE-SEA cruise with the Research Vessel (RV) "Cotes de la Manche", the specific objective was to determine if there was 14 C transfer as C0 2 between sea to land

A core-top study of dissolution effect on B/Ca in Globigerinoides sacculifer from the tropical Atlantic: Potential bias for paleo-reconstruction of seawater carbonate chemistry

International audiencehas been recently shown that B/Ca in planktonic foraminiferal calcite can be used as a proxy for seawater pH. Based on the study of surface sediments (multi-cores) retrieved along a depth transect on the Sierra Leone Rise (Eastern Equatorial Atlantic), we document the decrease of B/Ca and Mg/Ca of Globigerinoides sacculifer shells with increasing water depth and dissolution. This effect of dissolution on B/Ca may potentially represent a severe bias for paleo-pH reconstructions using this species. Samples of G. sacculifer were analyzed independently at two laboratories for B/Ca and Mg/Ca. Both sets of results show a systematic decrease of B/Ca and Mg/Ca along the depth transect, with an overall loss of ~14 µmol/mol (~15%) for B/Ca and of ~0.7 mmol/mol (~21%) for Mg/Ca between the shallowest (2640 m) and the deepest (4950 m) sites. Because of this dissolution effect, surface water pH reconstructed from B/Ca of G. sacculifer decreases by ~0.11 units between the shallowest site and the deepest site, a magnitude similar to the expected glacial/interglacial surface water pH changes

Assessing the provenance of ancient cotton at Hegra, Saudi Arabia (end of the 1st c. BC-5th c. AD) using new, modern strontium isotope results

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Rapid and accurate U–Th dating of ancient carbonates using inductively coupled plasma-quadrupole mass spectrometry

International audienc

四极杆电感耦合等离子体质谱仪 测定动物牙化石中 Ｕ和 Ｔｈ同位素

International audienceOver the past two decades TIMS and MC-ICP-MS have become the main techniques used for high-precision of 230 Th/U dating studies.Recently,a relatively simply and cheap technique for U-Th isotopic analysis was developed by using Inductively Coupled Plasma-Quadrupole Mass Spectrometry(ICP-QMS).With precisions about 0.3 % and 1 % for U and Th isotope analyses,this technique has the ability to estimate sample’s 230 Th/U age with 1 % ~10 % uncertainty.In this work,we use this new technique analyzed four fossil teeth coming from the Acheulian site of Venosa Loreto,southern Italy,where the faunal remains indicate an early Middle Pleistocene age.The previously published purification procedure of U and Th by UTEVA resins was modified for the fossil teeth.The UTEVA resins can efficiently extract U but not Th from the HNO3 solution of dental samples,in the presence of large amount of phosphates.In the present work,Th was allowed to co-precipitate with iron,then was loaded on anion exchange resin column in 7N HNO3 condition.In such strong HNO3 solution Th will be fixed onto the column,and can be diluted by 6N HCl.The U-Th isotope analysis with ICP-QMS was carried out on each dental tissue(enamel,dentine and cementum)of fossil teeth and yielded data with precision on average of 0.3 % and 0.6 % for 238 U and 232 Th contents,and of 0.3 % and 0.8 % for activity ratios of 234 U/238 U and 230 Th/238 U at 2σ uncertainty level,respectively.Our results show that U-contents in fossil teeth can be as high as 1000 ppm,but may differ from tissues by 1~2 orders of magnitude.On the other hand,for each tooth,dental tissues show substantial dispersion( >2σ)in their activity ratios of 234 U/238 U and 230 Th/238 U,consequently leading to scattered 230 Th/U dates,ranging from 139±2ka to 425±48ka.Fossil teeth thus are not ideal targets for 230 Th/U dating because of their open-system behavior,but the measured present-day U-Th isotopic information is useful for simulation of U-uptake histories experienced by dental tissues,and a combination of U-series and ESR analyses on fossil teeth seems a better way for age estimation

Neogene exhumation history of the Bergell massif (southeast Central Alps)

International audienceThe Bergell pluton is an elongated plutonic body emplaced during Oligocene time along the Insubric line in the central Alps. Reconstruction of its exhumation, based on apatite (U-Th)/He dating and one-dimensional thermal modelling, provides evidence for a three steps history: (i) following initial fast exhumation from >20-25 to ∼17 Ma, slow down of the exhumation rate until ∼10 Ma, (ii) quiescent phase from ∼10 to ∼5-6 Ma and (iii) an apparent increase of exhumation after ∼5-6 Ma. The decrease in exhumation rate is related with migration of thrusting south of the Bergell area in the Southern Alps (Lombardic phase). Increase in exhumation rate after ∼5-6 Ma is possibly related with Messinian base level drop, enhanced climatic variability (3-4 Ma) and intensification of glaciation (∼0.87 Ma)

Light and temperature effects on ¹¹B and B / Ca ratios of the zooxanthellate coral Acropora sp.: results from culturing experiments

International audienceThe boron isotopic composition (δ11B) of marine carbonates (e.g. corals) is increasingly utilised as a proxy for paleo-pH, with the strong correlation between δ11B of marine calcifiers and seawater pH now well documented. However, the potential roles of other environmental parameters that may also influence both the boron isotopic composition and boron concentration into coral aragonite are poorly known. To overcome this, the tropical scleractinian coral Acropora sp. was cultured under 3 different temperatures (22, 25 and 28 ˚C) and two light conditions (200 and 400 μmol photon m−2 s−1). The δ11B indicates an increase in internal pH that is dependent on the light conditions. Changes in light intensities from 200 to 400 μmol photon m−2 s−1 seem to indicate an apparent decrease in pH at the site of calcification, contrary to what is expected in most models of light-enhanced calcification. Thus, variations in light conditions chosen to mimic average annual variations of the natural environments where Acropora sp. colonies can be found could bias pH reconstructions by about 0.05 units. For both light conditions, a significant impact of temperature on 11B can be observed between 22 and 25˚C, corresponding to an increase of about 0.02 pH-units, while no further _11B increase can be observed from 25 to 28˚C. This non-linear temperature effect complicates the determination of a correction factor. B / Ca ratios decrease with increasing light, consistent with the decrease in pH at the site of calcification under enhanced light intensities. When all the other parameters are constant, boron concentrations in Acropora sp. increase with increasing temperatures and increasing carbonate ion concentrations. These observations contradict previous studies where B/Ca in corals was found to vary inversely with temperature, suggesting that the controlling factors driving boron concentrations have not yet been adequately identified and might be influenced by other environmental variables and/or species-specific responses