866 research outputs found

    Phylogenomic analysis of natural products biosynthetic gene clusters allows discovery of arseno-organic metabolites in model streptomycetes

    Get PDF
    We are indebted with Marnix Medema, Paul Straight and Sean Rovito, for useful discussions and critical reading of the manuscript, as well as with Alicia Chagolla and Yolanda Rodriguez of the MS Service of Unidad Irapuato, Cinvestav, and Araceli Fernandez for technical support in high-performance computing. This work was funded by Conacyt Mexico (grants No. 179290 and 177568) and FINNOVA Mexico (grant No. 214716) to FBG. PCM was funded by Conacyt scholarship (No. 28830) and a Cinvestav posdoctoral fellowship. JF and JFK acknowledge funding from the College of Physical Sciences, University of Aberdeen, UK.Peer reviewedPublisher PD

    Haematopoietic stem cells in perisinusoidal niches are protected from ageing.

    Get PDF
    With ageing, intrinsic haematopoietic stem cell (HSC) activity decreases, resulting in impaired tissue homeostasis, reduced engraftment following transplantation and increased susceptibility to diseases. However, whether ageing also affects the HSC niche, and thereby impairs its capacity to support HSC function, is still widely debated. Here, by using in-vivo long-term label-retention assays we demonstrate that aged label-retaining HSCs, which are, in old mice, the most quiescent HSC subpopulation with the highest regenerative capacity and cellular polarity, reside predominantly in perisinusoidal niches. Furthermore, we demonstrate that sinusoidal niches are uniquely preserved in shape, morphology and number on ageing. Finally, we show that myeloablative chemotherapy can selectively disrupt aged sinusoidal niches in the long term, which is linked to the lack of recovery of endothelial Jag2 at sinusoids. Overall, our data characterize the functional alterations of the aged HSC niche and unveil that perisinusoidal niches are uniquely preserved and thereby protect HSCs from ageing

    Randomized controlled phase 2 trial of hydroxychloroquine in childhood interstitial lung disease

    Get PDF
    Background No results of controlled trials are available for any of the few treatments offered to children with interstitial lung diseases (chILD). We evaluated hydroxychloroquine (HCQ) in a phase 2, prospective, multicentre, 1:1-randomized, double-blind, placebo-controlled, parallel-group/crossover trial. HCQ (START arm) or placebo were given for 4 weeks. Then all subjects received HCQ for another 4 weeks. In the STOP arm subjects already taking HCQ were randomized to 12 weeks of HCQ or placebo (= withdrawal of HCQ). Then all subjects stopped treatment and were observed for another 12 weeks. Results 26 subjects were included in the START arm, 9 in the STOP arm, of these four subjects participated in both arms. The primary endpoint, presence or absence of a response to treatment, assessed as oxygenation (calculated from a change in transcutaneous O 2 -saturation of ≄ 5%, respiratory rate ≄ 20% or level of respiratory support), did not differ between placebo and HCQ groups. Secondary endpoints including change of O 2 -saturation ≄ 3%, health related quality of life, pulmonary function and 6-min-walk-test distance, were not different between groups. Finally combining all placebo and all HCQ treatment periods did not identify significant treatment effects. Overall effect sizes were small. HCQ was well tolerated, adverse events were not different between placebo and HCQ. Conclusions Acknowledging important shortcomings of the study, including a small study population, the treatment duration, lack of outcomes like lung function testing below age of 6 years, the small effect size of HCQ treatment observed requires careful reassessments of prescriptions in everyday practice (EudraCT-Nr.: 2013-003714-40, www.clinicaltrialsregister.eu , registered 02.07.2013)

    Terrestrial Very-Long-Baseline Atom Interferometry:Workshop Summary

    Get PDF
    This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

    Get PDF
    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

    Get PDF
    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

    Get PDF
    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

    Get PDF
    Peer reviewe

    Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at root s=13 TeV

    Get PDF
    Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at root s = 13TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb(-1). Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12 +/- 0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.Peer reviewe
    • 

    corecore