244 research outputs found

    On the Role of Nitrogen Monoxide (Nitric Oxide) in the Nitration of a Tyrosine Derivative and Model Compounds

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    The nitration of tyrosine derivatives with nitrogen monoxide (nitric oxide) occurs only in the presence of dioxygen, and the hypothesized mechanism involves nitrogen dioxide (NO2). For better understanding of the reaction mechanism, the nitration of model compounds - such as 1- and 2-naphthols and their corresponding 2- and 1-nitroso derivatives with nitrogen monoxide in the presence and in the absence of dioxygen was studied. The results described here show that tyrosine and naphthols do not undergo nitrosation when they react with (NO)-N-., and so nitrosation of tyrosine in biological systems is highly unlikely. In addition, the oxidation of nitrosonaphthols reversible arrow isonitrosonaphthols by nitric oxide and its derivatives to the corresponding nitro derivatives does not involve the oxoammonium ion, as reported previously. The mechanistic proposals are supported mainly by ESR investigation and electrochemical data

    Reactions between 1-Methyl-2-phenyl-3-nitrosoindole, Activated with Benzoyl Chloride, with Indole and Indolizine Derivatives as Nucleophiles: a Case of 1,3-Migration.

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    2-Phenyl-3-nitrosoindole activated with PhCOCl reacts with indoles and indolizines (NuH) affording products of 1,2-addiction which undergo 1,3-nucleophilic migration in acid media

    A study of gas contaminants and interaction with materials in RPC closed loop systems

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    Resistive Plate Counters (RPC) detectors at the Large Hadron Collider (LHC) experiments use gas recirculation systems to cope with large gas mixture volumes and costs. In this paper a long-term systematic study about gas purifiers, gas contaminants and detector performance is discussed. The study aims at measuring the lifetime of purifiers with unused and used cartridge material along with contaminants release in the gas system. During the data-taking the response of several RPC double-gap detectors was monitored in order to characterize the correlation between dark currents, filter status and gas contaminants

    An analysis of materials used in the RPC detector and in the closed loop gas system of CMS at the LHC.

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    The results are reported of the study of materials used in the CERN Closed Loop recirculation gas system currently under test with the RPC muon detectors in the CMS experiment at the LHC. Studies include a sampling campaign in a low-radiation environment (cosmic rays at the CERN ISR test site). We describe the dedicated RPC chamber tests, the chemical analysis of the filters and gas used, and discuss the results of the Closed Loop system

    Middle ear cholesteatoma in 11 dogs

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    Middle ear cholesreatoma is a rare condition in dogs with chronic otitis. Otorrhea, otodinia, and pain on temporomandibular joint palpation are the most common clinical signs. Neurological abnormalities are often detectable. Computed tomography reveals the presence of an expansive and invasive unvascularized lesion involving the tympanic cavity and the bulla, with little or no contrast enhancement after administration of contrast mediu. Video-otoscopy may detect pearly growth or white/yellowish scales in the middle ear cavity. Surgery is the only therapy but is associated with a high risk of recurrence

    Loss of ISWI Function in Drosophila Nuclear Bodies Drives Cytoplasmic Redistribution of Drosophila TDP-43

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    Over the past decade, evidence has identified a link between protein aggregation, RNA biology, and a subset of degenerative diseases. An important feature of these disorders is the cytoplasmic or nuclear aggregation of RNA-binding proteins (RBPs). Redistribution of RBPs, such as the human TAR DNA-binding 43 protein (TDP-43) from the nucleus to cytoplasmic inclusions is a pathological feature of several diseases. Indeed, sporadic and familial forms of amyotrophic lateral sclerosis (ALS) and fronto-temporal lobar degeneration share as hallmarks ubiquitin-positive inclusions. Recently, the wide spectrum of neurodegenerative diseases characterized by RBPs functions' alteration and loss was collectively named proteinopathies. Here, we show that TBPH (TAR DNA-binding protein-43 homolog), the Drosophila ortholog of human TDP-43 TAR DNA-binding protein-43, interacts with the arcRNA hsr omega and with hsr omega-associated hnRNPs. Additionally, we found that the loss of the omega speckles remodeler ISWI (Imitation SWI) changes the TBPH sub-cellular localization to drive a TBPH cytoplasmic accumulation. Our results, hence, identify TBPH as a new component of omega speckles and highlight a role of chromatin remodelers in hnRNPs nuclear compartmentalization
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