51 research outputs found

    The effect of Pt surface orientation on the oscillatory electro-oxidation of glycerol

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    In the present paper, we have studied the influence of (bi)sulfate anion (0.1 and 0.5 M) on the electro-oxidation of glycerol on basal Pt(hkl) and stepped surfaces belonging to the series of Pt(S)[n(1 1 1) × (1 1 1)]. Cyclic voltammograms and derivative voltammetry pointed out that the catalytic activity decreases for Pt(1 1 1) and Pt(1 1 0) and, to a minor extent, for stepped surfaces in 0.5 mol/L H2SO4. Chronoamperometric curves demonstrated that above 0.60 V (vs RHE), for both concentrations (0.1 and 0.5 mol/L H2SO4), stepped surfaces and Pt(1 1 0) showed greater ability to catalyze the glycerol electro-oxidation in comparison with Pt(1 1 1). Potential oscillations were mapped along with slow galvanodynamic sweeps and studied at constant current. For Pt(1 1 1), no oscillations were found in the galvanodynamic regime, however, under the galvanostatic regime, period 1 oscillations were observed after a long induction period. The oscillations showed a very similar profile for stepped surfaces, even for the Pt(3 3 2) surface, which has a high density of (1 1 0) steps. Pattern changes were observed only for Pt(1 1 0) compared to other surfaces. Therefore, we conclude that (1 1 0) step sites influence the oscillatory behavior, thus the insertion of the steps favors the path of formation of inactive species, which compete for the same catalytic sites in a given potential region. The extinction of the mechanism oscillatory occurs differently due to the intrinsic characteristics of each surface electrode for the formation of (hydro)oxides.The authors acknowledge FAPESP (Grants No. 2013/16930-7 and 2019/22183-6), FAPEAL (process 60030-001076/2016), CAPES - Brasil (CAPES, Grant No. 0001, and for the scholarship, GBM, 88887.341974/2019-00). HV (Grant No. 306060/2017-5) and GTF (Grant No. 313455/2021-0) acknowledge CNPq for financial support. We gratefully acknowledge the support of the RCGI – Research Centre for Gas Innovation, hosted by the University of São Paulo (USP) and sponsored by FAPESP (2014/50279-4 and 2020/15230-5) and Shell Brazil, and the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas, and Biofuels Agency) through the R&D levy regulation

    Thiophene- and carbazole-substituted N-Methyl-Fulleropyrrolidine acceptors in PffBT4T-2OD based solar cells

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    The impact of fullerene side chain functionalization with thiophene and carbazole groups on the device properties of bulk-heterojunction polymer:fullerene solar cells is discussed through a systematic investigation of material blends consisting of the conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2′;5′,2″;5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) as donor and C60 or C70 fulleropyrrolidines as acceptors. The photovoltaic performance clearly depended on the molecular structure of the fulleropyrrolidine substituents although no direct correlation with the surface morphology of the photoactive layer, as determined by atomic force microscopy, could be established. Although some fulleropyrrolidines possess favorable lowest unoccupied molecular orbital levels, when compared to the standard PC71BM, they originated OPV cells with inferior efficiencies than PC71BM-based reference cells. Fulleropyrrolidines based on C60 produced, in general, better devices than those based on C70, and we attribute this observation to the detrimental effect of the structural and energetic disorder that is present in the regioisomer mixtures of C70-based fullerenes, but absent in the C60-based fullerenes. These results provide new additional knowledge on the effect of the fullerene functionalization on the efficiency of organic solar cells.This work was financially supported by: Base Funding — UIDB/00511/2020 of the Laboratory forProcess Engineering, Environment, Biotechnology and Energy — LEPABE — funded by national funds through theFCT/MCTES (PIDDAC). This work was partially funded within the scope of the project i3N, UIDB/50025/2020 & UIDP/50025/2020, financed by national funds through the FCT/MEC. Thanks are also due to FCT/MEC for thefinancial support to QOPNA (FCT UID/QUI/00062/2019), CICECO-Aveiro Institute of Materials (UIDB/50011/2020& UIDP/50011/2020), CQE (FCT UIDB/00100/2020), and CIQUP (FCT UID/QUI/UI0081/2019) research units, throughnational funds and where applicable co-financed by the FEDER, within the PT2020 Partnership Agreement. H.G.thanks Fundação para a Ciência e a Tecnologia (FCT) for his PhD scholarship (SFRH/BD/103009/2014). The researchcontracts of F.F. (REF. -168-89-ARH/2018) is funded by national funds (OE), through FCT—Fundação para aCiência e Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of article 23,of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. M.M.F. acknowledges also supportfrom FCT under the project IF/00894/2015

    The identification of TCF1+ progenitor exhausted T cells in THRLBCL may predict a better response to PD-1/PD-L1 blockade

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    T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a rare and aggressive variant of diffuse large B-cell lymphoma (DLBCL) that usually affects young to middle-aged patients, with disseminated disease at presentation. The tumor microenvironment (TME) plays a key role in THRLBCL due to its peculiar cellular composition (< 10% neoplastic B cells interspersed in a cytotoxic T-cell/histiocyte-rich background). A significant percentage of THRLBCL is refractory to rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (RCHOP)-based regimens and to chimeric antigen receptor T-cell therapy; thus, the development of a specific therapeutic approach for these patients represents an unmet clinical need. To better understand the interaction of immune cells in THRLBCL TME and identify more promising therapeutic strategies, we compared the immune gene expression profiles of 12 THRLBCL and 10 DLBCL samples, and further corroborated our findings in an extended in silico set. Gene coexpression network analysis identified the predominant role of the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis in the modulation of the immune response. Furthermore, the PD-1/PD-L1 activation was flanked by the overexpression of 48 genes related to the functional exhaustion of T cells. Globally, THRLBCL TME was highly interferon-inflamed and severely exhausted. The immune gene profiling findings strongly suggest that THRLBCL may be responsive to anti-PD-1 therapy but also allowed us to take a step forward in understanding THRLBCL TME. Of therapeutic relevance, we validated our results by immunohistochemistry, identifying a subset of TCF1(+) (T cell-specific transcription factor 1, encoded by the TCF7 gene) progenitor exhausted T cells enriched in patients with THRLBCL. This subset of TCF1(+) exhausted T cells correlates with good clinical response to immune checkpoint therapy and may improve prediction of anti-PD-1 response in patients with THRLBCL

    Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder

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    Background: Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries. Methods: Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries). Results: This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01. Conclusion: A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed

    Novel genetic loci associated with hippocampal volume

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    The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

    Genetic architecture of subcortical brain structures in 38,851 individuals

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    Subcortical brain structures are integral to motion, consciousness, emotions and learning. We identified common genetic variation related to the volumes of the nucleus accumbens, amygdala, brainstem, caudate nucleus, globus pallidus, putamen and thalamus, using genome-wide association analyses in almost 40,000 individuals from CHARGE, ENIGMA and UK Biobank. We show that variability in subcortical volumes is heritable, and identify 48 significantly associated loci (40 novel at the time of analysis). Annotation of these loci by utilizing gene expression, methylation and neuropathological data identified 199 genes putatively implicated in neurodevelopment, synaptic signaling, axonal transport, apoptosis, inflammation/infection and susceptibility to neurological disorders. This set of genes is significantly enriched for Drosophila orthologs associated with neurodevelopmental phenotypes, suggesting evolutionarily conserved mechanisms. Our findings uncover novel biology and potential drug targets underlying brain development and disease

    Novel genetic loci underlying human intracranial volume identified through genome-wide association

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    Intracranial volume reflects the maximally attained brain size during development, and remains stable with loss of tissue in late life. It is highly heritable, but the underlying genes remain largely undetermined. In a genome-wide association study of 32,438 adults, we discovered five novel loci for intracranial volume and confirmed two known signals. Four of the loci are also associated with adult human stature, but these remained associated with intracranial volume after adjusting for height. We found a high genetic correlation with child head circumference (ρgenetic=0.748), which indicated a similar genetic background and allowed for the identification of four additional loci through meta-analysis (Ncombined = 37,345). Variants for intracranial volume were also related to childhood and adult cognitive function, Parkinson’s disease, and enriched near genes involved in growth pathways including PI3K–AKT signaling. These findings identify biological underpinnings of intracranial volume and provide genetic support for theories on brain reserve and brain overgrowth

    Analysis of shared heritability in common disorders of the brain

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    ience, this issue p. eaap8757 Structured Abstract INTRODUCTION Brain disorders may exhibit shared symptoms and substantial epidemiological comorbidity, inciting debate about their etiologic overlap. However, detailed study of phenotypes with different ages of onset, severity, and presentation poses a considerable challenge. Recently developed heritability methods allow us to accurately measure correlation of genome-wide common variant risk between two phenotypes from pools of different individuals and assess how connected they, or at least their genetic risks, are on the genomic level. We used genome-wide association data for 265,218 patients and 784,643 control participants, as well as 17 phenotypes from a total of 1,191,588 individuals, to quantify the degree of overlap for genetic risk factors of 25 common brain disorders. RATIONALE Over the past century, the classification of brain disorders has evolved to reflect the medical and scientific communities' assessments of the presumed root causes of clinical phenomena such as behavioral change, loss of motor function, or alterations of consciousness. Directly observable phenomena (such as the presence of emboli, protein tangles, or unusual electrical activity patterns) generally define and separate neurological disorders from psychiatric disorders. Understanding the genetic underpinnings and categorical distinctions for brain disorders and related phenotypes may inform the search for their biological mechanisms. RESULTS Common variant risk for psychiatric disorders was shown to correlate significantly, especially among attention deficit hyperactivity disorder (ADHD), bipolar disorder, major depressive disorder (MDD), and schizophrenia. By contrast, neurological disorders appear more distinct from one another and from the psychiatric disorders, except for migraine, which was significantly correlated to ADHD, MDD, and Tourette syndrome. We demonstrate that, in the general population, the personality trait neuroticism is significantly correlated with almost every psychiatric disorder and migraine. We also identify significant genetic sharing between disorders and early life cognitive measures (e.g., years of education and college attainment) in the general population, demonstrating positive correlation with several psychiatric disorders (e.g., anorexia nervosa and bipolar disorder) and negative correlation with several neurological phenotypes (e.g., Alzheimer's disease and ischemic stroke), even though the latter are considered to result from specific processes that occur later in life. Extensive simulations were also performed to inform how statistical power, diagnostic misclassification, and phenotypic heterogeneity influence genetic correlations. CONCLUSION The high degree of genetic correlation among many of the psychiatric disorders adds further evidence that their current clinical boundaries do not reflect distinct underlying pathogenic processes, at least on the genetic level. This suggests a deeply interconnected nature for psychiatric disorders, in contrast to neurological disorders, and underscores the need to refine psychiatric diagnostics. Genetically informed analyses may provide important "scaffolding" to support such restructuring of psychiatric nosology, which likely requires incorporating many levels of information. By contrast, we find limited evidence for widespread common genetic risk sharing among neurological disorders or across neurological and psychiatric disorders. We show that both psychiatric and neurological disorders have robust correlations with cognitive and personality measures. Further study is needed to evaluate whether overlapping genetic contributions to psychiatric pathology may influence treatment choices. Ultimately, such developments may pave the way toward reduced heterogeneity and improved diagnosis and treatment of psychiatric disorders

    The genetic architecture of the human cerebral cortex

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    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
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