Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices

Substitutions near the hemagglutinin receptor-binding site determine the antigenic evolution of influenza A H3N2 viruses in U.S. swine

Swine influenza A virus is an endemic and economically important pathogen in pigs, with the potential to infect other host species. The hemagglutinin (HA) protein is the primary target of protective immune responses and the major component in swine influenza A vaccines. However, as a result of antigenic drift, vaccine strains must be regularly updated to reflect currently circulating strains. Characterizing the cross-reactivity between strains in pigs and seasonal influenza virus strains in humans is also important in assessing the relative risk of interspecies transmission of viruses from one host population to the other. Hemagglutination inhibition (HI) assay data for swine and human H3N2 viruses were used with antigenic cartography to quantify the antigenic differences among H3N2 viruses isolated from pigs in the United States from 1998 to 2013 and the relative cross-reactivity between these viruses and current human seasonal influenza A virus strains. Two primary antigenic clusters were found circulating in the pig population, but with enough diversity within and between the clusters to suggest updates in vaccine strains are needed. We identified single amino acid substitutions that are likely responsible for antigenic differences between the two primary antigenic clusters and between each antigenic cluster and outliers. The antigenic distance between current seasonal influenza virus H3 strains in humans and those endemic in swine suggests that population immunity may not prevent the introduction of human viruses into pigs, and possibly vice versa, reinforcing the need to monitor and prepare for potential incursions

Comment on "ferroelectricity-free lead halide perovskites" by A. Gomez, Q. Wang, A. R. Goni, M. Campoy-Quiles and A. Abate, Energy Environ. Sci., 2019, 12, 2537

This article comments on the recent publication ‘‘Ferroelectricity-free lead halide perovskites’’ by Gomez´et al. [DOI: 10.1039/c9ee00884e], in which the authors conclude that both methylammonium lead iodide (MAPbI$_{3}$) and the more advanced Cs$_{0.05}$(FA$_{0.83}$MA$_{0.17}$)$_{0.95}$Pb(I$_{0.83}$Br$_{0.17}$)$_{3}$ form non-ferroelectric thin-films. This conclusion is based on measuring the vertical piezoelectric effect by ‘‘direct piezoelectric force microscopy’’ (DPFM) and not seeing any domain patterns or other ferroelectric responses. The authors calibrated their measurement using a bulk reference sample of periodically poled lithium niobate with vertical polarization, which has all-different properties from MAPbI$_{3}$ or Cs$_{0.05}$(FA$_{0.83}$MA$_{0.17}$)$_{0.95}$Pb(I$_{0.83}$Br$_{0.17}$)$_{3}$ thin-films. In earlier works, it was pointed out that the polarization in large MAPbI$_{3}$ grains is vastly oriented in-plane and hence could remain invisible to any probing techniques with vertical sensitivity. In addition, the low spatial resolution of their measurements, the strong measurement noise, potential adventitious water contamination and the use of improper cantilever loads reduces the sensitivity of the measurement setup. This is why the conclusion on MAPbI$_{3}$ being non-ferroelectric is not supported by the measurement data

Quantitative differential proteomics of yeast extracellular matrix: there is more to it than meets the eye

Background: Saccharomyces cerevisiae multicellular communities are sustained by a scaffolding extracellular matrix, which provides spatial organization, and nutrient and water availability, and ensures group survival. According to this tissue-like biology, the yeast extracellular matrix (yECM) is analogous to the higher Eukaryotes counterpart for its polysaccharide and proteinaceous nature. Few works focused on yeast biofilms, identifying the flocculin Flo11 and several members of the HSP70 in the extracellular space. Molecular composition of the yECM, is therefore mostly unknown. The homologue of yeast Gup1 protein in high Eukaryotes (HHATL) acts as a regulator of Hedgehog signal secretion, therefore interfering in morphogenesis and cell-cell communication through the ECM, which mediates but is also regulated by this signalling pathway. In yeast, the deletion of GUP1 was associated with a vast number of diverse phenotypes including the cellular differentiation that accompanies biofilm formation. Methods: S. cerevisiae W303-1A wt strain and gup1Δ mutant were used as previously described to generate biofilmlike mats in YPDa from which the yECM proteome was extracted. The proteome from extracellular medium from batch liquid growing cultures was used as control for yECM-only secreted proteins. Proteins were separated by SDS-PAGE and 2DE. Identification was performed by HPLC, LC-MS/MS and MALDI-TOF/TOF. The protein expression comparison between the two strains was done by DIGE, and analysed by DeCyder Extended Data Analysis that included Principal Component Analysis and Hierarchical Cluster Analysis. Results: The proteome of S. cerevisiae yECM from biofilm-like mats was purified and analysed by Nano LC-MS/MS, 2D Difference Gel Electrophoresis (DIGE), and MALDI-TOF/TOF. Two strains were compared, wild type and the mutant defective in GUP1. As controls for the identification of the yECM-only proteins, the proteome from liquid batch cultures was also identified. Proteins were grouped into distinct functional classes, mostly Metabolism, Protein Fate/Remodelling and Cell Rescue and Defence mechanisms, standing out the presence of heat shock chaperones, metalloproteinases, broad signalling cross-talkers and other putative signalling proteins. The data has been deposited to the ProteomeXchange with identifier PXD001133.Conclusions: yECM, as the mammalian counterpart, emerges as highly proteinaceous. As in higher Eukaryotes ECM, numerous proteins that could allow dynamic remodelling, and signalling events to occur in/and via yECM were identified. Importantly, large sets of enzymes encompassing full antagonistic metabolic pathways, suggest that mats develop into two metabolically distinct populations, suggesting that either extensive moonlighting or actual metabolism occurs extracellularly. The gup1Δ showed abnormally loose ECM texture. Accordingly, the correspondent differences in proteome unveiled acetic and citric acid producing enzymes as putative players in structural integrity maintenance.This work was funded by the Marie Curie Initial Training Network GLYCOPHARM (PITN-GA-2012-317297), and by national funds from FCT I.P. through the strategic funding UID/BIA/04050/2013. Fábio Faria-Oliveira was supported by a PhD scholarship (SFRH/BD/45368/2008) from FCT (Fundação para a Ciência e a Tecnologia). We thank David Caceres and Montserrat MartinezGomariz from the Unidad de Proteómica, Universidad Complutense de Madrid – Parque Científico de Madrid, Spain for excellent technical assistance in the successful implementation of all proteomics procedures including peptide identification, and Joana Tulha from the CBMA, Universidade do Minho, Portugal, for helping with the SDS-PAGE experiments, and the tedious and laborious ECM extraction procedures. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium, via the PRIDE partner repository, with the dataset identifier PXD001133. We would like to thank the PRIDE team for all the help and support during the submission process.info:eu-repo/semantics/publishedVersio

Pseudo‐ Para ‐Substituted [2.2]Paracyclophanes for Hole Transport in Perovskite Solar Cells

2,2′,7,7′-Tetrakis(N,N-di-p-methoxyphenylamine)−9,9′-spirobifluorene (spiro-OMeTAD) is the prevalent hole transport layer in perovskite solar cells (PSCs) with regular device architecture. Yet, its spirobifluorene core and multistep synthesis make it rather expensive. For the further technological success of PSCs, novel scalable and inexpensive alternative hole transport layers are needed. Herein, a study of the structure-property relations of pseudo-para-substituted [2.2]paracyclophanes is presented. Eight different hole transport materials are synthesized via double CH activation, eliminating metal-containing substituents for cross-coupling reactions. The ionization potentials (IPs) of the disubstituted paracyclophanes (DiPCPs) are examined by photoelectron spectroscopy in air, cyclic voltammetry and theoretical calculations. Through variation of donor groups and π-linkers, IPs that span a range from 5.14 to 5.86 eV are achieved, demonstrating high customizability. From the eight novel materials, five showed good solubility and are implemented into PSCs. The solar cells with a hole transport layer of undoped 4,16-di(4-(2-thienyl)-N,N-bis(4-methoxyphenyl)aniline)[2.2]paracyclophane (DiPCP-2) exhibit a power conversion efficiency of 12.7% ± 0.4%. The facile synthesis of DiPCP-2 enables an estimated cost reduction by two thirds compared to spiro-OMeTAD

Impact of early enteral versus parenteral nutrition on mortality in patients requiring mechanical ventilation and catecholamines: study protocol for a randomized controlled trial (NUTRIREA-2)

BACKGROUND: Nutritional support is crucial to the management of patients receiving invasive mechanical ventilation (IMV) and the most commonly prescribed treatment in intensive care units (ICUs). International guidelines consistently indicate that enteral nutrition (EN) should be preferred over parenteral nutrition (PN) whenever possible and started as early as possible. However, no adequately designed study has evaluated whether a specific nutritional modality is associated with decreased mortality. The primary goal of this trial is to assess the hypothesis that early first-line EN, as compared to early first-line PN, decreases day 28 all-cause mortality in patients receiving IMV and vasoactive drugs for shock. METHODS/DESIGN: The NUTRIREA-2 study is a multicenter, open-label, parallel-group, randomized controlled trial comparing early PN versus early EN in critically ill patients requiring IMV for an expected duration of at least 48 hours, combined with vasoactive drugs, for shock. Patients will be allocated at random to first-line PN for at least 72 hours or to first-line EN. In both groups, nutritional support will be started within 24 hours after IMV initiation. Calorie targets will be 20 to 25 kcal/kg/day during the first week, then 25 to 30 kcal/kg/day thereafter. Patients receiving PN may be switched to EN after at least 72 hours in the event of shock resolution (no vasoactive drugs for 24 consecutive hours and arterial lactic acid level below 2 mmol/L). On day 7, all patients receiving PN and having no contraindications to EN will be switched to EN. In both groups, supplemental PN may be added to EN after day 7 in patients with persistent intolerance to EN and inadequate calorie intake. We plan to recruit 2,854 patients at 44 participating ICUs. DISCUSSION: The NUTRIREA-2 study is the first large randomized controlled trial designed to assess the hypothesis that early EN improves survival compared to early PN in ICU patients. Enrollment started on 22 March 2013 and is expected to end in November 2015. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01802099 (registered 27 February 2013)

Ferroelectric Properties of Perovskite Thin Films and Their Implications for Solar Energy Conversion

Whether or not methylammonium lead iodide (MAPbI3) is a ferroelectric semiconductor has caused controversy in the literature, fueled by many misunderstandings and imprecise definitions. Correlating recent literature reports and generic crystal properties with the authors’ experimental evidence, the authors show that MAPbI3 thin-films are indeed semiconducting ferroelectrics and exhibit spontaneous polarization upon transition from the cubic high-temperature phase to the tetragonal phase at room temperature. The polarization is predominantly oriented in-plane and is organized in characteristic domains as probed with piezoresponse force microscopy. Drift-diffusion simulations based on experimental patterns of polarized domains indicate a reduction of the Shockley–Read–Hall recombination of charge carriers within the perovskite grains due to the ferroelectric built-in field and allow reproduction of the electrical solar cell properties

Toward target 2035:EUbOPEN - a public-private partnership to enable & unlock biology in the open

Target 2035 is a global initiative that seeks to identify a pharmacological modulator of most human proteins by the year 2035. As part of an ongoing series of annual updates of this initiative, we summarise here the efforts of the EUbOPEN project whose objectives and results are making a strong contribution to the goals of Target 2035. EUbOPEN is a public-private partnership with four pillars of activity: (1) chemogenomic library collections, (2) chemical probe discovery and technology development for hit-to-lead chemistry, (3) profiling of bioactive compounds in patient-derived disease assays, and (4) collection, storage and dissemination of project-wide data and reagents. The substantial outputs of this programme include a chemogenomic compound library covering one third of the druggable proteome, as well as 100 chemical probes, both profiled in patient derived assays, as well as hundreds of data sets deposited in existing public data repositories and a project-specific data resource for exploring EUbOPEN outputs.</p