158 research outputs found

    A coumarin based gold(I)-alkynyl complex: a new Q1 class of supramolecular hydrogelators

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    A phosphine-gold(I)-alkynyl-coumarin complex, [Au{7-(prop-2-ine-1-yloxy)-1-benzopyran-2-one}-(DAPTA)] (1), was synthesized and the formation of long luminescent fibers in solution was characterized via fluorescence microscopy and dynamic light scattering. The fibers presented strong blue and green luminescence, suggesting that the gold(I) in the complex increased intersystem crossing due to the heavy atom effect, resulting in a significant increase in triplet emission. The X-ray structure of the fibers indicates that both aurophilic, π-π interactions and hydrogen bonding contribute to their formation in aqueous solvents

    Impaired cell growth under ammonium stress explained by modeling the energy cost of vacuole expansion in tomato leaves

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    Ammonium (NH4+)-based fertilization efficiently mitigates the adverse effects of nitrogen fertilization on the environment. However, high concentrations of soil NH4+ provoke growth inhibition, partly caused by the reduction of cell enlargement and associated with modifications of cell composition, such as an increase of sugars and a decrease in organic acids. Cell expansion depends largely on the osmotic-driven enlargement of the vacuole. However, the involvement of subcellular compartmentation in the adaptation of plants to ammonium nutrition has received little attention, until now. To investigate this, tomato (Solanum lycopersicum) plants were cultivated under nitrate and ammonium nutrition and the fourth leaf was harvested at seven developmental stages. The vacuolar expansion was monitored and metabolites and inorganic ion contents, together with intracellular pH, were determined. A data-constrained model was constructed to estimate subcellular concentrations of major metabolites and ions. It was first validated at the three latter developmental stages by comparison with subcellular concentrations obtained experimentally using non-aqueous fractionation. Then, the model was used to estimate the subcellular concentrations at the seven developmental stages and the net vacuolar uptake of solutes along the developmental series. Our results showed ammonium nutrition provokes an acidification of the vacuole and a reduction in the flux of solutes into the vacuoles. Overall, analysis of the subcellular compartmentation reveals a mechanism behind leaf growth inhibition under ammonium stress linked to the higher energy cost of vacuole expansion, as a result of alterations in pH, the inhibition of glycolysis routes and the depletion of organic acids.TP benefited from a cotutelle PhD (University of Bordeaux and University of the Basque Country) and thanks the University of the Basque Country (UPV/EHU, Spain) for his PhD grant during the execution of this work. This research was financially supported by the Basque Government (IT-932-16) and the Spanish Government (BIO2017-84035-R co-funded by Fondo Europeo para el Desarrollo Regional [FEDER]). Analytics were supported by MetaboHUB (ANR-11-INBS-0010) and PHENOME (ANR-11-INBS-0012) projects. Technical support was provided by Cedric Cassan, Ana Renovales and Mandy Bordas. The authors also thank SGIker (UPV/EHU, FEDER, EU) for the technical and human support provided

    Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

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    Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

    Kinematics and Age of Syn-Intrusive Detachment Faulting in the Southern Alps: Evidence for Early Permian Crustal Extension and Implications for the Pangea A Versus B Controversy

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    Permian basin formation and magmatism in the Southern Alps of Italy have been interpreted as expressions of a WSW‐ENE‐trending, dextral megashear zone transforming Early Permian Pangea B into Late Permian Pangea A between ~285 and 265 Ma. In an alternative model, basin formation and magmatism resulted from N‐S crustal extension. To characterize Permian tectonics, we studied the Grassi Detachment Fault, a low‐angle extensional fault in the central Southern Alps. The footwall forms a metamorphic core complex affected by upward‐increasing, top‐to‐the‐southeast mylonitization. Two granitoid intrusions occur in the core complex, the synmylonitic Val Biandino Quartz Diorite and the postmylonitic Valle San Biagio Granite. U‐Pb zircon dating yielded crystallization ages of 289.1 ± 4.5 Ma for the former and 286.8 ± 4.9 Ma for the latter. Consequently, detachment‐related mylonitic shearing took place during the Early Permian and ended at ~288 Ma, but kinematically coherent brittle faulting continued. Considering 30° anticlockwise rotation of the Southern Alps since Early Permian, the extension direction of the Grassi Detachment Fault was originally ~N‐S. Even though a dextral continental wrench system has long been regarded as a viable model at regional scale, the local kinematic evidence is inconsistent with this and, rather, supports N‐S extensional tectonics. Based on a compilation of >200 U‐Pb zircon ages, we discuss the evolution and tectonic framework of Late Carboniferous to Permian magmatism in the Alps

    COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

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    Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≀ 18 years: 69, 48, 23; 85%), older adults (≄ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

    L'organisation territoriale de la recherche publique en Bretagne : une approche systémique

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    From a new study of public research on a Regional scale, we question the reality of a territorial system of research in Brittany. It is both a question of identifying the scientific characteristics of the Breton laboratories and encircling their space organization. From an original data base, we thus determine the fields of excellence and the effects of polarization or of proximity which come out from it. Thanks to a graphic and cartographic synthesis, we also define logics of site and network. We also apprehend the range of the radiation of collaborations between researchers and the degree of connectivity of the units on all the scales. Furthermore the multiscale approach allows us to clarifying the governance of public research. If the institutional action remains largely dominated by the prerogative of the State, it is nevertheless a fact that the role of the actors of research becomes more and more complex with the increasing intervention of Europe and Regions, multiplying in fact the devices of support and incentive to the structuring. Hence the interest of a systemic step to understand the political and scientists interactions that exert their influence on the socio-economic development of the Breton territory by the means of research. In a context of globalisation, the stakes of international competitiveness and attractivity should not occult the mission of regional planning. Consequently, this thesis has as much a theoretical objective, to supplement the still limited knowledge on the organization of research at Regional level, operational one, to warn the institutional strategies.A partir d'une Ă©tude inĂ©dite de la recherche publique Ă  l'Ă©chelle d'une rĂ©gion, nous interrogeons la rĂ©alitĂ© d'un systĂšme territorial de recherche en Bretagne. Il s'agit Ă  la fois d'identifier les particularitĂ©s scientifiques des laboratoires bretons et de cerner leur organisation spatiale. En nous appuyant notamment sur une base de donnĂ©es originale, nous dĂ©terminons ainsi les domaines d'excellence et les effets de polarisation ou encore de proximitĂ© qui en ressortent. GrĂące Ă  une synthĂšse graphique et cartographique, nous cernons Ă©galement les logiques de site et de rĂ©seau. De mĂȘme, nous apprĂ©hendons la portĂ©e du rayonnement des collaborations entre chercheurs et le degrĂ© de connectivitĂ© des unitĂ©s Ă  toutes les Ă©chelles. L'approche multiscalaire nous permet en outre d'Ă©clairer la gouvernance de la recherche publique. Si l'action institutionnelle reste largement dominĂ©e par la prĂ©rogative de l'Etat, il n'en demeure pas moins que le jeu des acteurs de la recherche se complexifie avec l'intervention croissante de l'Europe et des RĂ©gions, multipliant de fait les dispositifs de soutien et d'incitation Ă  la structuration. D'oĂč l'intĂ©rĂȘt d'une dĂ©marche systĂ©mique pour comprendre les interactions politiques et scientifiques qui exercent leur influence sur le dĂ©veloppement socio-Ă©conomique du territoire breton par le biais de la recherche. Dans un contexte de mondialisation, les enjeux de compĂ©titivitĂ© et d'attractivitĂ© internationales ne doivent pas occulter la mission d'amĂ©nagement du territoire. Par consĂ©quent, cette thĂšse revĂȘt autant un objectif thĂ©orique, pour complĂ©ter les connaissances encore assez limitĂ©es sur l'organisation de la recherche au niveau rĂ©gional, qu'opĂ©rationnel, pour aviser les stratĂ©gies institutionnelles

    La recherche universitaire bretonne et ses réseaux

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