608 research outputs found

    8-PropargylaminoBODIPY: unprecedented blue-emitting pyrromethene dye. Synthesis, photophysics and laser properties

    Get PDF
    Highly emitting 8-propargylaminoBODIPY (8-PAB) 2 was prepared in 94% yield. Unlike any other BODIPY structure hitherto described in the literature, 2 displays efficient emission in the blue region of the visible spectrum with a fluorescence quantum yield up to 0.94 and high laser efficiency (35%) at 483 nm.Grants GTO-2007-C02-69094 (CONCyTEG) (Mexico), MAT2007-65778-C02-01 and -02 of the Spanish MICINN are gratefully acknowledged. V. Martin thanks CSIC for her JAE-postdoctoral contract.Peer reviewe

    Correcting flaws in the assignment of nitrogen chemical environments in N-doped graphene

    Get PDF
    X-ray Photoelectron Spectroscopy (XPS) applied to N-doped graphene leads to a rather broad N(1s) core level signal that, based on different sources available in the literature, is most often interpreted by fitting the experimental spectra to three peaks. The resulting N(1s) features are assigned to graphitic, pyrrolic, and pyridinic nitrogen, even if these are far from being uniquely defined in the literature. This broadly accepted interpretation has been questioned by recent accurate Hartree-Fock calculations concluding that graphitic and pyrrolic N(1s) core level binding energies are too close to be distinguished. Consideration of models with N in other so far unexplored environments such as N dimers or N at defects show some variations in the calculated core level binding energies. However, these are not large enough to justify a third peak and suggest that the usual three peaks interpretation of the N(1s) XPS in N-doped graphene may be an artefact caused by the fitting procedure. New measurements have been carried out for samples of N-doped graphene and the obtained N(1s) spectra fitted to two or three peaks. It turns out that the spectra can be equally fitted using two or three peaks but only the former is consistent with the results of the unbiased ab initio calculations which calls for a revision of the usual assignment

    Influence of Sparger Type and Regime of Fluid on Biomass and Lipid Productivity of Chlorella vulgaris Culture in a Pilot Airlift Photobioreactor

    Get PDF
    The effect of different types of spargers and the influence of the air flow rate on biomass and lipids production by Chlorella vulgaris was evaluated. These data allowed correlation of the hydrodynamic behavior of the photobioreactor with the byproducts production. The hydrodynamic characterization was developed by determining the mixing time (tM), hold-up, and total volumetric mass transfer coefficient of CO2, kLa(CO2)T, at increasing air flow rates for three different spargers: star-shaped, cross-shaped and porous glass surface sparger. The hydrodynamic characterization showed that the tM decreased, while the hold-up values and the kLa(CO2)T increased as a result of the increment in the volumetric air flow rate between 5 to 17 L min–1. The highest biomass and lipid concentrations were determined at the higher aeration rate (20 L min–1), which was correlated with the lower tM, the higher hold-up and kLa(CO2)T values. Biomass and lipid production showed an inverse correlation. The highest biomass concentration (750 mg L–1) and the lowest lipid concentration (10 mg L–1) were measured with the star sparger. In contrast, when the lowest biomass concentration was obtained (240 mg L–1), the highest lipid concentration of 196 mg L–1 was measured with the glass sparger. The maximum biomass productivity values were determined at the lower aeration rate and the star sparger, with the minimum power per unit of volume, which could be useful for a cost-effective process

    Spider venom neurotoxin based bioinsecticides: A novel bioactive for the control of the Asian citrus psyllid Diaphorina citri (Hemiptera)

    Get PDF
    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a key vector of the phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas) associated with huanglongbing (HLB), the most serious and currently incurable disease of citrus worldwide. Here we report the first investigation into the potential use of a spider venom-derived recombinant neurotoxin, ω/κ-HxTx-Hv1h (hereafter HxTx-Hv1h) when delivered alone or when fused to snowdrop lectin (Galanthus nivalis agglutinin; GNA) to control D. citri. Proteins, including GNA alone, were purified from fermented transformed yeast Pichia pastoris cultures. Recombinant HxTx-Hv1h, HxTx-Hv1h/GNA and GNA were all orally toxic to D. citri, with Day 5 median lethal concentrations (LC 50) derived from dose-response artificial diet assays of 27, 20 and 52 μM, respectively. Western analysis of whole insect protein extracts confirmed that psyllid mortality was attributable to protein ingestion and that the fusion protein was stable to cleavage by D. citri proteases. When applied topically (either via droplet or spray) HxTx-Hv1h/GNA was the most effective of the proteins causing >70 % mortality 5 days post treatment, some 2 to 3-fold higher levels of mortality as compared to the toxin alone. By contrast, no significant mortality or phenotypic effects were observed for bumble bees (Bombus terrestris L.) fed on the recombinant proteins in acute toxicity assays. This suggests that HxTx-Hv1h/GNA has potential as a novel bioinsecticide for the management of D. citri offering both enhanced target specificity as compared to chemical pesticides and compatibility with integrated pest management (IPM) strategies

    Three-Neutrino Mixing after the First Results from K2K and KamLAND

    Get PDF
    We analyze the impact of the data on long baseline \nu_\mu disappearance from the K2K experiment and reactor \bar\nu_e disappearance from the KamLAND experiment on the determination of the leptonic three-generation mixing parameters. Performing an up-to-date global analysis of solar, atmospheric, reactor and long baseline neutrino data in the context of three-neutrino oscillations, we determine the presently allowed ranges of masses and mixing and we consistently derive the allowed magnitude of the elements of the leptonic mixing matrix. We also quantify the maximum allowed contribution of \Delta m^2_{21} oscillations to CP-odd and CP-even observables at future long baseline experiments.Comment: Some typos correcte

    Band Depopulation of Graphene Nanoribbons Induced by Chemical Gating with Amino Groups

    Get PDF
    Altres ajuts: Xunta de Galicia (ED431G/09); Gobierno Vasco (IT1246-19, IT-1255-19); Diputación Foral de Gipuzkoa (RED 2019-096); CERCA Program/Generalitat de Catalunya; Program Interreg V-A España-Francia-Andorra (194/16 TNI)The electronic properties of graphene nanoribbons (GNRs) can be precisely tuned by chemical doping. Here we demonstrate that amino (NH) functional groups attached at the edges of chiral GNRs (chGNRs) can efficiently gate the chGNRs and lead to the valence band (VB) depopulation on a metallic surface. The NH-doped chGNRs are grown by on-surface synthesis on Au(111) using functionalized bianthracene precursors. Scanning tunneling spectroscopy resolves that the NH groups significantly upshift the bands of chGNRs, causing the Fermi level crossing of the VB onset of chGNRs. Through density functional theory simulations we confirm that the hole-doping behavior is due to an upward shift of the bands induced by the edge NH groups

    GDF15 mediates the metabolic effects of PPARβ/δ by activating AMPK

    Get PDF
    Peroxisome proliferator-activated receptor β/ (PPARβ/) activates AMP-activated protein kinase (AMPK) and plays a crucial role in glucose and lipid metabolism. Here, we examined whether the beneficial effects of PPARβ/δ activation depended on growth differentiation factor 15 (GDF15), a stress response cytokine that regulates energy metabolism. Pharmacological PPARβ/δ activation increased GDF15 levels and ameliorated glucose intolerance, fatty acid oxidation, endoplasmic reticulum stress, inflammation and activated AMPK in HFD-fed mice, whereas these effects were abrogated by the injection of a GDF15 neutralizing antibody and in Gdf15-/- mice. The AMPK-p53 pathway was involved in the PPARβ/δ-mediated increase in GDF15, which in turn activated again AMPK. Finally, Gdf15-/- mice showed reduced AMPK activation in skeletal muscle, whereas GDF15 administration resulted in AMPK activation in this organ. Collectively, these data reveal a novel mechanism by which PPARβ/δ activation increases the levels of GDF15 via AMPK and p53, which in turn mediates the metabolic effects of PPARβ/δ by sustaining AMPK activation. Abbreviations: Acadm, acyl-CoA dehydrogenase medium chain; Acox, acyl-CoA oxidase; AMPK, AMP-activated protein kinase; ATF4, activating transcription factor 4; BiP/GRP78, Binding immunoglobulin protein/78-kDa glucose-regulated protein; CC, compound C; Chop, C/EBP homologous protein; Cpt-1, carnitine palmitoyl-transferase 1; eIF2eukaryotic translation initiation factor 2 ER, endoplasmic reticulum; ERK, extracellular signal-regulated kinase; FGF21, fibroblast growth factor 21; GDF15, growth differentiation factor 15; GFRAL, glial-derived neurotrophic factor receptor α-like; HFD, high-fat diet; Pdk4, pyruvate dehydrogenase kinase 4; IRS, insulin receptor substrate; PGC-1PPAR co-activator 1 PPAR peroxisome proliferator-activated receptor; SOCS3, suppressor of cytokine signaling 3; STAT3, signal transducer and activator of transcription 3; Vldlr, very-low density lipoprotein receptor

    Unraveling the electronic structure of narrow atomically precise chiral graphene nanoribbons

    Full text link
    This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposesRecent advances in graphene-nanoribbon-based research have demonstrated the controlled synthesis of chiral graphene nanoribbons (chGNRs) with atomic precision using strategies of on-surface chemistry. However, their electronic characterization, including typical figures of merit like band gap or frontier band's effective mass, has not yet been reported. We provide a detailed characterization of (3,1)-chGNRs on Au(111). The structure and epitaxy, as well as the electronic band structure of the ribbons, are analyzed by means of scanning tunneling microscopy and spectroscopy, angle-resolved photoemission, and density functional theoryThe project leading to this publication has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 635919), from the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, grant nos. MAT2016-78293-C6, FIS2015-62538-ERC), from the Basque Government (grant nos. IT-621-13, PI-2015-1-42, PI-2016-1-0027), from the European Commission in FP7 FET-ICT “Planar Atomic and Molecular Scale Devices” (PAMS) project (contract no. 610446), from the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016−2019, ED431G/09), and from the European Regional Development Fund (ERDF

    Effects of Mediterranean Diet and Physical Activity on Pulmonary Function: A Cross-Sectional Analysis in the ILERVAS Project

    Get PDF
    A few studies showed that both adherence to Mediterranean diet (MedDiet) and physical activity practice have a positive impact on pulmonary function in subjects with lung disease. These associations are not well studied in subjects free from lung disease. In a cross-sectional study conducted in 3020 middle-aged subjects free of lung disease, adherence to the MedDiet using the Mediterranean Diet Adherence Screener, and physical activity practice using the International Physical Activity Questionnaire short form were recorded. Respiratory function was assessed using forced spirometry and the results were evaluated according to the Global initiative for Chronic Obstructive Lung Disease. Logistic regression models were used to analyze the associations between adherence to the MedDiet and physical activity practice with the presence of ventilatory defects. Participants with a high adherence to MedDiet, in comparison to those with low adherence, had both higher forced vital capacity (FVC; 100 (87–109) vs. 94 (82–105) % of predicted, p = 0.003) and forced expired volume in the first second (FEV1; 100 (89–112) vs. 93 (80–107) % of predicted, p < 0.001). According to their degree of physical activity, those subjects with a high adherence also had both higher FVC (100 (88–107) vs. 94 (83–105) % of predicted, p = 0.027) and FEV1 (100 (89–110) vs. 95 (84–108) % of predicted, p = 0.047) in comparison with those with low adherence. The multivariable logistic regression models showed a significant and independent association between both low adherence to MedDiet and low physical activity practice, and the presence of altered pulmonary patterns, with differences between men and women. However, no joint effect between adherence to MedDiet and physical activity practice on respiratory function values was observed. Low adherence to MedDiet and low physical activity practice were independently associated with pulmonary impairment. Therefore, the lung mechanics seem to benefit from heart-healthy lifestyle behaviors.This study was supported by grants from the Diputació de Lleida, Generalitat de Catalunya (2017SGR696 and SLT0021600250), Instituto de Salud Carlos III (Fondo de Investigación Sanitaria PI12/00803 and PI15/00260), and European Union (European Regional Development Fund, Fondo Europeo de Desarrollo Regional, “Una manera de hacer Europa”). CIBER de Diabetes y Enfermedades Metabólicas Asociadas, CIBER de Nutrición y Obesidad, and CIBER de Enfermedades Respiratorias are initiatives of the Instituto de Salud Carlos III

    The Deubiquitinating Enzyme Ataxin-3 Regulates Ciliogenesis and Phagocytosis in the Retina

    Get PDF
    Expansion of a CAG repeat in ATXN3 causes the dominant polyglutamine disease spinocerebellar ataxia type 3 (SCA3), yet the physiological role of ATXN3 remains unclear. Here, we focus on unveiling the function of Ataxin-3 (ATXN3) in the retina, a neurological organ amenable to morphological and physiological studies. Depletion of Atxn3 in zebrafish and mice causes morphological and functional retinal alterations and, more precisely, photoreceptor cilium and outer segment elongation, cone opsin mislocalization, and cone hyperexcitation. ATXN3 localizes at the basal body and axoneme of the cilium, supporting its role in regulating ciliary length. Abrogation of Atxn3 expression causes decreased levels of the regulatory protein KEAP1 in the retina and delayed phagosome maturation in the retinal pigment epithelium. We propose that ATXN3 regulates two relevant biological processes in the retina, namely, ciliogenesis and phagocytosis, by modulating microtubule polymerization and microtubule-dependent retrograde transport, thus positing ATXN3 as a causative or modifier gene in retinal/macular dystrophies
    corecore