41 research outputs found
Iroquois Complex Genes Induce Co-Expression of rhodopsins in Drosophila
The Drosophila eye is a mosaic that results from the stochastic distribution of two ommatidial subtypes. Pale and yellow ommatidia can be distinguished by the expression of distinct rhodopsins and other pigments in their inner photoreceptors (R7 and R8), which are implicated in color vision. The pale subtype contains ultraviolet (UV)-absorbing Rh3 in R7 and blue-absorbing Rh5 in R8. The yellow subtype contains UV-absorbing Rh4 in R7 and green-absorbing Rh6 in R8. The exclusive expression of one rhodopsin per photoreceptor is a widespread phenomenon, although exceptions exist. The mechanisms leading to the exclusive expression or to co-expression of sensory receptors are currently not known. We describe a new class of ommatidia that co-express rh3 and rh4 in R7, but maintain normal exclusion between rh5 and rh6 in R8. These ommatidia, which are localized in the dorsal eye, result from the expansion of rh3 into the yellow-R7 subtype. Genes from the Iroquois Complex (Iro-C) are necessary and sufficient to induce co-expression in yR7. Iro-C genes allow photoreceptors to break the “one receptor–one neuron” rule, leading to a novel subtype of broad-spectrum UV- and green-sensitive ommatidia
Towards a muon collider
A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work
Multiethnic Meta-Analysis Identifies Ancestry-Specific and Cross-Ancestry Loci for Pulmonary Function
Nearly 100 loci have been identified for pulmonary function, almost exclusively in studies of European ancestry populations. We extend previous research by meta-analyzing genome-wide association studies of 1000 Genomes imputed variants in relation to pulmonary function in a multiethnic population of 90,715 individuals of European (N = 60,552), African (N = 8429), Asian (N = 9959), and Hispanic/Latino (N = 11,775) ethnicities. We identify over 50 additional loci at genome-wide significance in ancestry-specific or multiethnic meta-analyses. Using recent fine-mapping methods incorporating functional annotation, gene expression, and differences in linkage disequilibrium between ethnicities, we further shed light on potential causal variants and genes at known and newly identified loci. Several of the novel genes encode proteins with predicted or established drug targets, including KCNK2 and CDK12. Our study highlights the utility of multiethnic and integrative genomics approaches to extend existing knowledge of the genetics of lung function and clinical relevance of implicated loci
Association of Forced Vital Capacity with the Developmental Gene <i>NCOR2</i>
Background Forced Vital Capacity (FVC) is an important predictor of all-cause mortality in the absence of chronic respiratory conditions. Epidemiological evidence highlights the role of early life factors on adult FVC, pointing to environmental exposures and genes affecting lung development as risk factors for low FVC later in life. Although highly heritable, a small number of genes have been found associated with FVC, and we aimed at identifying further genetic variants by focusing on lung development genes. Methods Per-allele effects of 24,728 SNPs in 403 genes involved in lung development were tested in 7,749 adults from three studies (NFBC1966, ECRHS, EGEA). The most significant SNP for the top 25 genes was followed-up in 46,103 adults (CHARGE and SpiroMeta consortia) and 5,062 chi
Genome-wide association analysis identifies six new loci associated with forced vital capacity
Forced vital capacity (FVC), a spirometric measure of pulmonary function, reflects lung volume and is used to diagnose and monitor lung diseases. We performed genome-wide association study meta-analysis of FVC in 52,253 individuals from 26 studies and followed up the top associations in 32,917 additional individuals of European ancestry. We found six new regions associated at genome-wide significance (P < 5 × 10−8) with FVC in or near EFEMP1, BMP6, MIR129-2–HSD17B12, PRDM11, WWOX and KCNJ2. Two loci previously associated with spirometric measures (GSTCD and PTCH1) were related to FVC. Newly implicated regions were followed up in samples from African-American, Korean, Chinese and Hispanic individuals. We detected transcripts for all six newly implicated genes in human lung tissue. The new loci may inform mechanisms involved in lung development and the pathogenesis of restrictive lung disease
Multiethnic meta-analysis identifies ancestry-specific and cross-ancestry loci for pulmonary function
Nearly 100 loci have been identified for pulmonary function, almost exclusively in studies of European ancestry populations. We extend previous research by meta-analyzing genome-wide association studies of 1000 Genomes imputed variants in relation to pulmonary function in a multiethnic population of 90,715 individuals of European (N = 60,552), African (N = 8429), Asian (N = 9959), and Hispanic/Latino (N = 11,775) ethnicities. We identify over 50 additional loci at genome-wide significance in ancestry-specific or multiethnic meta-analyses. Using recent fine-mapping methods incorporating functional annotation, gene expression, and differences in linkage disequilibrium between ethnicities, we further shed light on potential causal variants and genes at known and newly identified loci. Several of the novel genes encode proteins with predicted or established drug targets, including KCNK2 and CDK12. Our study highlights the utility of multiethnic and integrative genomics approaches to extend existing knowledge of the genetics of l
Ni composite electrodes for hydrogen generation: Activation of Nb-based semiconductors
The hydrogen evolution reaction depends on the accumulation of electrons on the catalytic center to enable the two-electron processes involved in water reduction. This work reports on the modification of inexpensive nickel (Ni) composite electrodes with engineered semiconductor heterojunctions based on earth-abundant transition metals that show superior hydrogen generation activity in the presence of a non-toxic electrolyte (K2CO3). This is, small amounts of cobalt (Co) or copper (Cu) oxides can improve the reactivity of composite electrodes formed by deposition of titanium (Ti) or niobium (Nb) semiconductors onto Ni surfaces. In general, modified Nb-based semiconductors show better performance and their enhanced activity can be understood in terms of modified surface potentials upon formation of semiconductor-Ni heterojunctions. Photoelectrochemical activity can be detected in the presence of Cu oxides, where hydrogen generation onset potential is reduced under UV–Vis light irradiation. The study demonstrates that small composition changes can greatly affect the activity of Nb-based Ni composite electrodes, showing exciting new applications for Nb-based materials
Highly Efficient Hybrid Ni/Nitrogenated Graphene Electrocatalysts for Hydrogen Evolution Reaction
Two nickel/nitrogenated graphene hybrid electrodes (Ni-NrGONH3 and Ni-NrGOAPTES) were synthesized, and their catalytic activity with respect to the hydrogen evolution reaction (HER) in alkaline media was analyzed. Incorporation of nitrogen to the carbon structure in graphene oxide (GO) or reduced GO (rGO) flakes in aqueous solutions was carried out based on two different configurations. NrGONH3 particles were obtained by a hydrothermal method using ammonium hydroxide as the precursor, and NGOAPTES particles were obtained by silanization (APTES functionalization) of GO sheets. Aqueous dispersions containing NrGONH3 and NGOAPTES particles were added to the traditional nickel Watts plating bath in order to prepare the Ni-NrGONH3 and Ni-NrGOAPTES catalysts, respectively. Nickel substrates were coated with the hybrid nickel electrodeposits and used as electrodes for hydrogen production. The Ni-NrGO catalysts show a higher activity than the conventional nickel electrodeposited electrodes, particularly the ones containing APTES molecules because they allow obtaining a hydrogen current density 130% higher than conventional Ni-plated electrodes with a Watts bath in the absence of additives. In addition, both catalysts show a low deactivation rate during the ageing treatment, which is a sign of a longer midlife for the catalyst. Cyclic voltammetry and electrochemical impedance spectroscopy measurements were used for examination of the catalytic efficiency of hybrid Ni-NrGO electrodes for HER in KOH solution. High values of exchange current densities, 8.53 × 10-4 and 2.53 × 10-5 mA cm-2 for HER in alkaline solutions on Ni-NrGONH3 and Ni-NrGOAPTES electrodes, respectively, were obtained.Fil: Gomez, Melisa Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Loiácono, Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Pérez, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Franceschini, Esteban Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Lacconi, Gabriela Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin
Synthesis of rGO–Nps hybrids with electrocatalytic activity for hydrogen evolution reaction
A hybrid nanomaterial with palladium nanoparticles (PdNps) supported on reduced graphene oxide (rGO) flakes, dispersed in an aqueous solution was synthesized through a reproducible and scalable electrochemical method. The rGO–PdNps hybrid with excellent stability and a narrow range of size distribution in the aqueous dispersion is obtained. In a second step, additional plasmonic characteristics were provided by forming Au–Pd bimetallic nanostructures in the rGO flakes, through the gold nanoparticles formation by galvanic replacement on the Pd surface sites at the rGO–PdNps hybrid. The interaction of the rGO–AuPdNps with the PVP binder in aqueous dispersion was investigated by SERS (surface enhancement of Raman scattering) spectroscopy. Furthermore, both rGO–PdNps and rGO–AuPdNps hybrid nanomaterials were deposited by drop-casting on glassy carbon electrodes in order to evaluate their electrocatalytic activity for hydrogen evolution reaction (HER). Experimental findings from cyclic voltammetry in 0.5 M H2SO4 solution show that both hybrids exhibit activation of HER kinetics. Electrodes modified with rGO–AuPdNps show a current density of HER at −0.6 V vs. SCE of 9.71 mAcm−2, while that recorded for glassy carbon electrodes containing rGO was 0.18 mAcm−2 considering the geometrical area of the electrodes.L.A.P. thanks CONICET for the postdoctoral fellowship. J.M.C. and F.F. thank EVC-CIN2020 students and SECyT-UNC doctoral fellowships, respectively. G.I.L. and E.A.F. are permanent research fellows of CONICET. The authors thank Dr. Ezequiel Leiva for very useful discussions on copper UPD measurements. This work was supported by projects from FONCyT PICT–2017-0250 (Argentina), CONICET PUE2017, and SECyT–UNC. The authors thank LAMARX, LANN-INFIQC laboratories for their assistance in XPS and SEM/EDX, Raman spectroscopy, and XRD measurements, respectively. G.I.L. thanks to the Alexander Von Humboldt Foundation for the equipment subsidy grant.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe