252 research outputs found

    Graphical Encoding of a Spatial Logic for the pi-Calculus

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    This paper extends our graph-based approach to the verification of spatial properties of π-calculus specifications. The mechanism is based on an encoding for mobile calculi where each process is mapped into a graph (with interfaces) such that the denotation is fully abstract with respect to the usual structural congruence, i.e., two processes are equivalent exactly when the corresponding encodings yield isomorphic graphs. Behavioral and structural properties of π-calculus processes expressed in a spatial logic can then be verified on the graphical encoding of a process rather than on its textual representation. In this paper we introduce a modal logic for graphs and define a translation of spatial formulae such that a process verifies a spatial formula exactly when its graphical representation verifies the translated modal graph formula

    Corrosion resistance and antibacterial properties of copper coating deposited by cold gas spray

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    This work describes the morphology, corrosion resistance, and antibacterial performance of copper coating deposited onto carbon steel by cold gas spray (CGS). Cross-sectional images of the coating showed a dense microstructure, with porosity lower than 1%. XRD analysis revealed no oxides or phases different to pure copper. The results of electrochemical tests demonstrated the efficient barrier properties and the compact microstructure of the coating, which protected the substrate against corrosion in chloride solution for > 1000 h. The copper coating was effective as an antimicrobial agent for inhibiting the growth of Staphylococcus aureus, with bacterial growth being completely inhibited after 10 min of direct contact between the bacteria and the coating surface

    Thermal analysis in oxidative and pyrolysis conditions of alkaline earth metals picolinates using the techniques:TG-DSC, DSC, MWTA, HSM and EGA (TG-DSC-FTIR and HSM-MS)

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    Made available in DSpace on 2019-10-06T15:58:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-10-01Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)University of HuddersfieldSynthesis, characterization, thermal stability and pyrolysis of some alkaline earth picolinates M(C6H5NO2)2⋅nH2O (where M = Mg(II), Ca(II), Sr(II) and Ba(II) and n = di (Mg), mono (Ca), hemi three (Sr) hydrated) were investigated using a range of techniques including simultaneous thermogravimetry and differential scanning calorimetry (TG–DSC), evolved gas analysis (EGA), differential scanning calorimetry (DSC), Hot-Stage microscopy (HSM), powder X-ray diffractometry (PXRD), complexometry with EDTA and elemental analysis (EA). The TG-DSC curves show that the hydrated compounds dehydrate in a single step of mass loss and the thermal stability of the anhydrous compound is little influenced from the atmosphere used. On the other hand, the mechanisms of thermal decomposition are profoundly influenced by the atmosphere used, as can also be observed in the EGA data. In addition, a comparison between two calorimetric techniques, Microwave Thermal Analysis (MWTA) and DSC, was made which showed similar profiles. Two evolved gas analysis (EGA) techniques: TG-DSC coupled to FTIR and HSM coupled to a quadrupole mass spectrometer (MS) were also used to provide additional information about the pyrolysis mechanism.Universidade Estadual Paulista (UNESP) Instituto de QuímicaThermal Methods Research Unit Department of Chemistry University of Huddersfield, HuddersfieldInstituto Federal de Educação Ciência e Tecnologia do Paraná (IFPR)Instituto Federal de Educação Ciência e Tecnologia de Rondônia (IFRO)Universidade Estadual Paulista (UNESP) Faculdade de Ciências Departamento de QuímicaUniversidade Estadual Paulista (UNESP) Instituto de QuímicaUniversidade Estadual Paulista (UNESP) Faculdade de Ciências Departamento de Químic

    Photo-induced electron transfer in supramolecular materials of titania nanostructures and cytochrome c

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    In the present paper, we report on the molecular interaction and photochemistry of TiO2 nanoparticles (NPs) and cytochrome c systems for understanding the effects of supramolecular organization and electron transfer by using two TiO2 structures: P25 TiO2 NPs and titanate nanotubes. The adsorption and reduction of cytochrome c heme iron promoted by photo-excited TiO2, arranged as P25 TiO2 NPs and as nanotubes, were characterized using electronic absorption spectroscopy, thermogravimetric analysis, and atomic force microscopy. In an aqueous buffered suspension (pH 8.0), the mass of cytochrome c adsorbed on the P25 TiO2 NP surface was 2.3 fold lower (0.75 μg m−2) than that adsorbed on the titanate nanotubes (1.75 μg m−2). Probably due to the high coverage of titanate nanotubes by adsorbed cytochrome c, the low amount of soluble remaining protein was not as efficiently photo-reduced by this nanostructure as it was by the P25 TiO2 NPs. Cytochrome c, which desorbed from both titanium materials, did not exhibit changes in its redox properties. In the presence of the TiO2 NPs, the photo-induced electron transfer from water to soluble cytochrome c heme iron was corroborated by the following findings: (i) identification by EPR of the hydroxyl radical production during the irradiation of an aqueous suspension of TiO2 NPs, (ii) impairment of a cytochrome c reduction by photo-excited TiO2 in the presence of dioxane, which affects the dielectric constant of the water, and (iii) change in the rate of TiO2-promoted cytochrome c reduction when water was replaced with D2O. The TiO2-promoted photo-reduction of cytochrome c was reverted by peroxides. Cytochrome c incorporated in the titanate nanotubes was also reversibly reduced under irradiation, as confirmed by EPR and UV-visible spectroscopy21974177426CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP475235/2010-0; 2011/01541-0Sem informação2008/04849-0; 2009/15558-1; 2011/01541-

    Porphyrin–nanodiamond hybrid materials—active, stable and reusable cyclohexene oxidation catalysts

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    funded by FCT-Foundation for Science and Technology, I.P., under projects UIDB/00313/2020; PTDC/QUI-OUT/27996/2017 (DUALPI); POCI-01-0145-FEDER-027996; POCI-01-0145-FEDER-016387; UIDB/50006/2020 (Associate Laboratory for Green Chemistry-LAQV); MATIS (CENTRO-010145-FEDER-00014); Base Funding-UIDB/50020/2020 of the Associate Laboratory LSRE-LCM-funded by national funds through FCT/MCTES (PIDDAC); and 5625-DRI-DAAD-2020/21. SACC also acknowledges FCT Investigador FCT program (IF/01381/2013/CP1160/CT0007) and Scientific Employment Stimulus -Institutional Call (CEECINST/00102/2018). The authors also thank Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) for CEPOF 2013/07276-1, and INCT "Basic Optics and Applied to Life Sciences" (FAPESP 2014/50857-8, CNPq 465360/2014-9). A.R.L. Caires acknowledges CAPES-PrInt funding program (grant number 88887.353061/2019-00 and 88881.311921/2018-01). J.G.B. thanks the Dutch Research Council (NWO) for funding as a part of the Open Technology Programme (project number 16361). L.D. Dias thanks FAPESP for the Post-doc grant 2019/13569-8. F.M.S.R. thanks FCT for the PhD grant (PD/BD/114340/2016).The quest for active, yet “green” non-toxic catalysts is a continuous challenge. In this work, covalently linked hybrid porphyrin–nanodiamonds were prepared via ipso nitro substitution reaction and characterized by X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, infrared spectroscopy (IR) and thermogravimetry-differential scanning calorimetry (TG-DSC). The amine-functionalized nanodiamonds (ND@NH2 ) and 2-nitro-5,10,15,20-tetra(4-trifluoromethylphenyl)porphyrin covalently linked to nanodiamonds (ND@βNH-TPPpCF3 ) were tested using Allium cepa as a plant model, and showed neither phytotoxicity nor cytotoxicity. The hybrid nanodiamond–copper(II)–porphyrin material ND@βNH-TPPpCF3-Cu(II) was also evaluated as a reusable catalyst in cyclohexene allylic oxidation, and displayed a remarkable turnover number (TON) value of ≈265,000, using O2 as green oxidant, in the total absence of sacrificial additives, which is the highest activity ever reported for said allylic oxidation. Additionally, ND@βNH-TPPpCF3-Cu(II) could be easily separated from the reaction mixture by centrifugation, and reused in three consecutive catalytic cycles without major loss of activity.publishersversionpublishe

    Linoleic acid improves PIEZO2 dysfunction in a mouse model of Angelman Syndrome

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    Angelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability and atypical behaviors. AS results from loss of expression of the E3 ubiquitin-protein ligase UBE3A from the maternal allele in neurons. Individuals with AS display impaired coordination, poor balance, and gait ataxia. PIEZO2 is a mechanosensitive ion channel essential for coordination and balance. Here, we report that PIEZO2 activity is reduced in Ube3a deficient male and female mouse sensory neurons, a human Merkel cell carcinoma cell line and female human iPSC-derived sensory neurons with UBE3A knock-down, and de-identified stem cell-derived neurons from individuals with AS. We find that loss of UBE3A decreases actin filaments and reduces PIEZO2 expression and function. A linoleic acid (LA)-enriched diet increases PIEZO2 activity, mechano-excitability, and improves gait in male AS mice. Finally, LA supplementation increases PIEZO2 function in stem cell-derived neurons from individuals with AS. We propose a mechanism whereby loss of UBE3A expression reduces PIEZO2 function and identified a fatty acid that enhances channel activity and ameliorates AS-associated mechano-sensory deficits.This work was supported by the Neuroscience Institute at UTHSC (Research Associate Matching Salary Support to J.L.), the Federico Baur endowed chair in Nanotechnology (to F.J.S.-V., 0020206BA1), a pilot research award from the Foundation for Prader-Willi Research (to L.T.R.), the Neuroscience Institute Research Supports Grant 2020 program (to V.V., and J.F.C.-M.), and the National Institutes of Health (R01GM133845 to V.V. and R01GM125629 to J.F.C.-M.)

    Sessions as Propositions

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    Recently, Wadler presented a continuation-passing translation from a session-typed functional language, GV, to a process calculus based on classical linear logic, CP. However, this translation is one-way: CP is more expressive than GV. We propose an extension of GV, called HGV, and give translations showing that it is as expressive as CP. The new translations shed light both on the original translation from GV to CP, and on the limitations in expressiveness of GV.Comment: In Proceedings PLACES 2014, arXiv:1406.331
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