1,135 research outputs found

    Synthesis and characterization of new D-π-A and A-π-D-π-A type oligothiophene derivatives

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    In this work we present a series of newly synthesized conjugated oligothiophene derivatives, with different numbers of central thiophene units, and different donor/acceptor architectures. Electrochemical and spectroscopic data have also been reported. We used thiophene or bithiophene as central Donor core units, 3-octylthiophenes as π-bridge and solubilizing sub-units, and ethyl cyanoacetate or rhodanine moieties as Acceptor end groups, in order to get D-π-A and A-π-D-π-A molecular architectures. The length of synthesized oligothiophenes ranges from three to eight thiophene units, a variety that is sufficient to put in evidence different optical and electrochemical as well as semiconducting characteristics. Oligothiophene compounds can be regarded not only as models for the study of structure-property relationships relatives to polythiophenes, but also they present a large number of applications in the field of Organic Electronics (i.e.: as donors in bulk-heterojunction solar cells as well as hole-transporting layer materials in perovskite solar cells, among others)

    NHC in Imidazolium Acetate Ionic Liquids: Actual or Potential Presence?

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    Ionic liquids (ILs) are considered in the majority of cases green solvents, due to their virtually null vapor pressure and to the easiness in recycling them. In particular, imidazolium ILs are widely used in many fields of Chemistry, as solvents or precursors of N-heterocyclic carbenes (NHCs). The latter are easily obtained by deprotonation of the C2-H, usually using strong bases or cathodic reduction. Nevertheless, it is known that weaker bases (e.g., triethylamine) are able to promote C2-H/D exchange. From this perspective, the possibility of deprotonating C2-H group of an imidazolium cation by means of a basic counter-ion was seriously considered and led to the synthesis of imidazolium ILs spontaneously containing NHCs. The most famous of this class of ILs are N,N'-disubstituted imidazolium acetates. Due to the particular reactivity of this kind of ILs, they were appointed as "organocatalytic ionic liquids" or "proto-carbenes." Many papers report the use of these imidazolium acetates in organocatalytic reactions (i. e., catalyzed by NHC) or in stoichiometric NHC reactions (e.g., with elemental sulfur to yield the corresponding imidazole-2-thiones). Nevertheless, the actual presence of NHC in N,N'-disubstituted imidazolium acetate is still controversial. Moreover, theoretical studies seem to rule out the presence of NHC in such a polar environment as an IL. Aim of this Mini Review is to give the reader an up-to-date overview on the actual or potential presence of NHC in such an "organocatalytic ionic liquid," both from the experimental and theoretical point of view, without the intent to be exhaustive on N,N'-disubstituted imidazolium acetate applications

    Fault Awareness in the MPI 4.0 Session Model

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    The latest version of MPI introduces new functionalities like the Session model, but it still lacks fault management mechanisms. Past efforts produced tools and MPI standard extensions to manage fault presence, including ULFM. These measures are effective against faults but do not fully support the new additions to the standard. In this paper, we combine the fault management possibilities of ULFM with the new Session model functionality introduced in version 4.0 of the standard. We focus on the communicator creation procedure, highlighting criticalities and proposing a method to circumvent them. The experimental campaign shows that the proposed solution does not significantly affect applications' execution time and scalability while better managing the insurgence of faults

    Capecitabine-Related Fourth Nerve Palsy: A Case Report

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    Introduction: Capecitabine has rarely been associated with neurotoxicity. Cerebellar ataxia, multifocal leukoencephalopathy, and sensorimotor peripheral neuropathy have been reported in the literature. A case of 6th nerve palsy associated with capecitabine has also been described. This article reports the first case of capecitabine-related 4th nerve palsy. Case presentation: A 72-year-old Caucasian woman was referred by the Oncology Department because she had been complaining of binocular diplopia for 6 months. The symptoms started 1 month after the introduction of capecitabine. A diagnosis of right 4th nerve palsy was made using the Parks three-step test and the Hess test. Neuroimaging analysis was negative. A slow but progressive deterioration of function was confirmed during a year of follow-up. On suspicion of a chemotherapy-related palsy, capecitabine was discontinued and switched to vinorelbine. Subsequent improvement of the clinical picture was confirmed within 2 months. Conclusion: The recognition of chemotherapy-related neurotoxicity is of paramount importance in the management of oncology patients. Once secondary invasion of the brain or the orbit by the tumor itself is ruled out, it must be suspected to prevent further deterioration

    Electrochemical synthesis of carbon quantum dots

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    Carbon quantum dots (CDs) are “small” carbon nanostructures with excellent photoluminescence properties, together with low-toxicity, high biocompatibility, excellent dispersibility in water as well as organic solvents. Due to their characteristics, CDs have been studied for a plethora of applications as biosensors, luminescent probes for photodynamic and photothermal therapy, fluorescent inks and many more. Moreover, the possibility to obtain carbon dots from biomasses and/or organic waste has strongly promoted the interest in this class of carbon-based nanoparticles, having a promising impact in the view of circular economy and sustainable processes. Within this context, electrochemistry proved to be a green, practical, and efficient method for the synthesis of high-quality CDs, with the possibility to fine-tune their characteristics by changing operational parameters. This review outlines the principal and most recent advances in the electrochemical synthesis of CDs, focusing on the electrochemical set-up optimization

    Pandemic 2009 H1N1 virus infection associated with purpuric skin lesions: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The influenza virus infection may be severe in non-immune people. Common complications of influenza virus include upper and lower respiratory tract infections, otitis media, myocarditis, acute respiratory distress syndrome and multi-organ failure. There have been cases of vasculitis following influenza vaccination, and rash and acute purpura may occur in certain viral infections. To the best of our knowledge, there are no reports concerning cases of systemic vasculitis associated with pandemic 2009 (H<sub>1</sub>N<sub>1</sub>) infection.</p> <p>Case presentation</p> <p>A 23-year-old Caucasian woman was hospitalized at the "L. Spallanzani" National Institute for Infectious Diseases in Rome, Italy. Clinical and radiological features including laboratory findings of this case are illustrated. Notably, the patient had fever, severe abdominal pain, hematuria, arthritis, and purpuric manifestations associated with a normal platelet count. Nasopharyngeal and rectal swabs revealed pandemic 2009 (H<sub>1</sub>N<sub>1</sub>) virus by reverse-transcriptase-polymerase-chain-reaction assay. Routine laboratory analyses showed elevated inflammatory parameters. The autoimmune panel tests were normal. Steroid therapy associated with oseltamivir achieved an evident and rapid improvement. On day seven the patient chose to leave the hospital against medical advice.</p> <p>Conclusion</p> <p>Complications related to influenza infection can be life threatening, particularly in immunocompromised patients. Henoch-Schönlein purpura triggered by the novel influenza virus infection could be an attractive pathogenetic hypothesis. We have discussed both the diagnosis and the challenge of therapy protocols. Steroid therapy is part of the management of severe vasculitis. Our case suggests that steroid therapy associated with antivirals can prevent the risk of further complications such as hemorrhage and multi-organ failure during severe vasculitis, without enhancing the virulence of the influenza virus. The possible role of pandemic 2009 (H<sub>1</sub>N<sub>1</sub>) in the pathogenesis of hemorrhagic manifestations should be further investigated.</p

    Implementing a distributed mobile calculus using the IMC framework

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    In the last decade, many calculi for modelling distributed mobile code have been proposed. To assess their merits and encourage use, implementations of the calculi have often been proposed. These implementations usually consist of a limited part dealing with mechanisms that are specific of the proposed calculus and of a significantly larger part handling recurrent mechanisms that are common to many calculi. Nevertheless, also the "classic" parts are often re-implemented from scratch. In this paper we show how to implement a well established representative of the family of mobile calculi, the distributed [pi]-calculus, by using a Java middleware (called IMC - Implementing Mobile Calculi) where recurrent mechanisms of distributed and mobile systems are already implemented. By means of the case study, we illustrate a methodology to accelerate the development of prototype implementations while concentrating only on the features that are specific of the calculus under consideration and relying on the common framework for all the recurrent mechanisms like network connections, code mobility, name handling, etc
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