275 research outputs found

    Effect of Light on a Tin Cathode in Stannous Acid Solution

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    This preliminary experiment study makes it possible to demonstrate that, in the case of the Sn/Sn(II) system, the effect of the light can be at first explained by the lowering of potential barriers.mThe study was made using unfiltered light which was simultaneously outside the absorption region of the solution and below the photoelectric threshold of tin

    Polypyrrole-Fe2O3 nanohybrid materials for electrochemical storage

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    We report on the synthesis and electrochemical characterization of nanohybrid polypyrrole (PPy) (PPy/Fe2O3) materials for electrochemical storage applications. We have shown that the incorporation of nanoparticles inside the PPy notably increases the charge storage capability in comparison to the “pure” conducting polymer. Incorporation of large anions, i.e., paratoluenesulfonate, allows a further improvement in the capacity. These charge storage modifications have been attributed to the morphology of the composite in which the particle sizes and the specific surface area are modified with the incorporation of nanoparticles. High capacity and stability have been obtained in PC/NEt4BF4 (at 20 mV/s), i.e., 47 mAh/g, with only a 3% charge loss after one thousand cyles. The kinetics of charge–discharge is also improved by the hybrid nanocomposite morphology modifications, which increase the rate of insertion–expulsion of counter anions in the bulk of the film. A room temperature ionic liquid such as imidazolium trifluoromethanesulfonimide seems to be a promising electrolyte because it further increases the capacity up to 53 mAh/g with a high stability during charge–discharge processes

    The common-866G > A variant in the promoter of UCP2 is associated with decreased risk of coronary artery disease in type 2 diabetic men

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    OBJECTIVE-Uncoupling protein 2 (UCP2) is a physiological downregulator of reactive oxygen species generation and plays an antiatherogenic role in the vascular wall. A common variant in the UCP2 promoter (-866G>A) modulates mRNA expression, with increased expression associated with the A allele. We investigated association of this variant with coronary artery disease (CAD) in two cohorts of type 2 diabetic subjects.RESEARCH DESIGN and METHODS-We studied 3,122 subjects from the 6-year prospective Non-Insulin-Dependent Diabetes, Hypertension, Microalbuminuria, Cardiovascular Events, and Ramipril (DIABHYCAR) Study (14.9% of CAD incidence at follow-up). An independent, hospital-based cohort of 335 men, 52% of whom had CAD, was also studied.RESULTS-We observed an inverse association of the A allele with incident cases of CAD in a dominant model (hazard risk 0.88 [95% CI 0.80-0.96]; P = 0.006). Similar results were observed for baseline cases of CAD. Stratification by sex confirmed an allelic association with CAD in men, whereas no association was observed in women. All CAD phenotypes considered-myocardial infarction, angina pectoris, coronary artery bypass graft (CABG), and sudden death-contributed significantly to the association. Results were replicated in a cross-sectional study of an independent cohort (odds ratio 0.47 [95% CI 0.25-0.89]; P = 0.02 for a recessive model).CONCLUSIONS-The A allele of the -866G>A variant of UCP2 was associated with reduced risk of CAD in men with type 2 diabetes in a 6-year prospective study. Decreased risk of myocardial infarction, angina pectoris, CABG, and sudden death contributed individually and significantly to the reduction of CAD risk. This association was independent of other common CAD risk factors.INSERM, Fac Med Xavier Bichat, U695, F-75018 Paris, FranceCochin Hosp, AP HP, Dept Immunol & Diabetol, Paris, FranceUniv São Paulo, Lab Cellular & Mol Endocrinol, São Paulo, BrazilUniversidade Federal de São Paulo, Mol Endocrinol Lab, São Paulo, BrazilFed Fac Fdn Med Sci Porto Alegre, Post Grad Program Med Sci, Porto Alegre, RS, BrazilHop La Pitie Salpetriere, Dept Cardiol, AP HP, Paris, FranceUniv Paris 07, Paris, FranceUniv Paris 05, Paris, FranceUniversidade Federal de São Paulo, Mol Endocrinol Lab, São Paulo, BrazilWeb of Scienc

    Resolving the Role of Plant Glutamate Dehydrogenase. I. in vivo Real Time Nuclear Magnetic Resonance Spectroscopy Experiments

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    In higher plants the glutamate dehydrogenase (GDH) enzyme catalyzes the reversible amination of 2-oxoglutarate to form glutamate, using ammonium as a substrate. For a better understanding of the physiological function of GDH either in ammonium assimilation or in the supply of 2-oxoglutarate, we used transgenic tobacco (Nicotiana tabacum L.) plants overexpressing the two genes encoding the enzyme. An in vivo real time 15N-nuclear magnetic resonance (NMR) spectroscopy approach allowed the demonstration that, when the two GDH genes were overexpressed individually or simultaneously, the transgenic plant leaves did not synthesize glutamate in the presence of ammonium when glutamine synthetase (GS) was inhibited. In contrast we confirmed that the primary function of GDH is to deaminate Glu. When the two GDH unlabeled substrates ammonium and Glu were provided simultaneously with either [15N]Glu or 15NH4+ respectively, we found that the ammonium released from the deamination of Glu was reassimilated by the enzyme GS, suggesting the occurrence of a futile cycle recycling both ammonium and Glu. Taken together, these results strongly suggest that the GDH enzyme, in conjunction with NADH-GOGAT, contributes to the control of leaf Glu homeostasis, an amino acid that plays a central signaling and metabolic role at the interface of the carbon and nitrogen assimilatory pathways. Thus, in vivo NMR spectroscopy appears to be an attractive technique to follow the flux of metabolites in both normal and genetically modified plants

    The Type and the Position of HNF1A Mutation Modulate Age at Diagnosis of Diabetes in Patients with Maturity-Onset Diabetes of the Young (MODY)-3

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    OBJECTIVE—The clinical expression of maturity-onset diabetes of the young (MODY)-3 is highly variable. This may be due to environmental and/or genetic factors, including molecular characteristics of the hepatocyte nuclear factor 1-α (HNF1A) gene mutation. RESEARCH DESIGN AND METHODS—We analyzed the mutations identified in 356 unrelated MODY3 patients, including 118 novel mutations, and searched for correlations between the genotype and age at diagnosis of diabetes. RESULTS—Missense mutations prevailed in the dimerization and DNA-binding domains (74%), while truncating mutations were predominant in the transactivation domain (62%). The majority (83%) of the mutations were located in exons 1- 6, thus affecting the three HNF1A isoforms. Age at diagnosis of diabetes was lower in patients with truncating mutations than in those with missense mutations (18 vs. 22 years, P = 0.005). Missense mutations affecting the dimerization/DNA-binding domains were associated with a lower age at diagnosis than those affecting the transactivation domain (20 vs. 30 years, P = 10−4). Patients with missense mutations affecting the three isoforms were younger at diagnosis than those with missense mutations involving one or two isoforms (P = 0.03). CONCLUSIONS—These data show that part of the variability of the clinical expression in MODY3 patients may be explained by the type and the location of HNF1A mutations. These findings should be considered in studies for the search of additional modifier genetic factors

    Conducting fabrics of polyester coated with polypyrrole and doped with graphene oxide

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    Polyester (PES) has been coated with polypyrrole (PPy) to produce conducting fabrics. Graphene oxide (GO) has been used in different concentrations (10, 20 and 30% weight) as counter ion to neutralize the positive charges of the PPy structure. Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) of the PPy/GO powders corroborated the incorporation of GO as counter ion due to the presence of O in the EDX spectrum, as well as an excess of C, arising from GO contribution. The doping level (N+/N) decreased with the GO content. Field emission scanning electron microscopy (FESEM) showed the formation of the PPy/GO coating and the incorporation of GO in the composite. Electrochemical impedance spectroscopy (EIS) in solid state and solution, cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM) were used to test the electrical properties and electroactivity of the fabrics. There was a decrease in the electrical properties and electroactivity as the GO content increased. The conductivity of the fabrics could be tuned by varying the GO content.Spanish Ministerio de Ciencia e Innovación (contract CTM2011-23583) for the financial support. Conselleria d'Educació, Formació i Ocupació (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship. C2011-UMINHO-2C2T-01 FCT funding from Programa Compromisso para a Ciência 2008, Portugal. XPS studies were performed at CEMUP (University of Porto, Portugal) facilities. Electron Microscopy Service of the UPV (Universitat Politècnica de València) is gratefully acknowledged for help with FESEM and EDX characterization

    ‘La Beauté’: Art and Dialogism in the Poetry of Baudelaire

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    Studies of Baudelaire’s poem ‘La Beauté’ have generally agreed that it has a key role to play in our understanding of his aesthetic theories, but have differed wildly in how this role is interpreted. The present study brings together arguments that see the speaker of the poem, Beauty, as a statue, along with those that understand the poem as being fundamentally ironic. Situating ‘La Beauté’ in the context of Baudelaire’s art criticism allows us to understand it as part of his engagement in debates within the visual arts. This gives us a new reading of Beauty’s claims as voicing the positions of neo-classical idealism, and specifically those of nineteenth-century academic theorists influenced by the eighteenth-century German inventor of art history, Winckelmann. Recognizing the importance of Winckelmann in approaching this poem sheds light on the rejection of movement and emotion that is pronounced by Beauty, and which contradict Baudelaire’s theoretical positions expressed elsewhere. The sonnet is thus incorporating the language of a speaker who is distinct from the lyric ‘je’ and cannot be reduced to a mask for him or a part of his divided self. This language and the position it expresses are framed within the sonnet, whose implicit irony leads to what Bakhtin calls double voicing. This approach offers a new reading of ‘La Beauté’ in formal terms as an example of Bakhtinian dialogism within lyric poetry

    The Clinical Variability of Maternally Inherited Diabetes and Deafness Is Associated with the Degree of Heteroplasmy in Blood Leukocytes

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    Context: Maternally inherited diabetes and deafness (MIDD) is a rare form of diabetes with a matrilineal transmission, sensorineural hearing loss, and macular pattern dystrophy due to an A to G transition at position 3243 of mitochondrial DNA (mtDNA) (m.3243A>G). The phenotypic heterogeneity of MIDD may be the consequence of different levels of mutated mtDNA among mitochondria in a given tissue. Objective: The aim of the present study was thus to ascertain the correlation between the severity of the phenotype in patients with MIDD and the level of heteroplasmy in the blood leukocytes. Participants: The GEDIAM prospective multicenter register was initiated in 1995. Eighty-nine Europid patients from this register, with MIDD and the mtDNA 3243A>G mutation, were included. Patients with MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) or with mitochondrial diabetes related to other mutations or to deletions of mtDNA were excluded. Results: A significant negative correlation was found between levels of heteroplasmy and age of the patients at the time of sampling for molecular analysis, age at the diagnosis of diabetes, and body mass index. After adjustment for age at sampling for molecular study and gender, the correlation between heteroplasmy levels and age at the diagnosis of diabetes was no more significant. The two other correlations remained significant. A significant positive correlation between levels of heteroplasmy and HbA1c was also found and remained significant after adjustment for age at molecular sampling and gender. Conclusions: These results support the hypothesis that heteroplasmy levels are at least one of the determinants of the severity of the phenotype in MIDD. Heteroplasmy levels are at least one of the determinants of the severity of the phenotype of maternally inherited diabetes and deafness

    Recognition of Human Proinsulin Leader Sequence by Class I–Restricted T-Cells in HLA-A*0201 Transgenic Mice and in Human Type 1 Diabetes

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    OBJECTIVE— A restricted region of proinsulin located in the B chain and adjacent region of C-peptide has been shown to contain numerous candidate epitopes recognized by CD8+ T-cells. Our objective is to characterize HLA class I–restricted epitopes located within the preproinsulin leader sequence
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