1,511 research outputs found

    A similarity principle for locally solvable vector fields

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    AbstractThis paper establishes a weak similarity principle for the class of locally solvable complex vector fields in the plane. The main tool is a local solvability result in an appropriate space of bounded mean oscillation functions

    Experimental assessment of the performance of two marine coatings to curb biofilm formation of microfoulers

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    Biofilms formed on submerged marine surfaces play a critical role in the fouling process, causing increased fuel consumption, corrosion, and high maintenance costs. Thus, marine biofouling is a major issue and motivates the development of antifouling coatings. In this study, the performance of two commercial marine coatings, a foul-release silicone-based paint (SilRef) and an epoxy resin (EpoRef), was evaluated regarding their abilities to prevent biofilm formation by Cyanobium sp. and Pseudoalteromonas tunicata (common microfoulers). Biofilms were developed under defined hydrodynamic conditions to simulate marine settings, and the number of biofilm cells, wet weight, and thickness were monitored for 7 weeks. The biofilm structure was analyzed by confocal laser scanning microscopy (CLSM) at the end-point. Results demonstrated that EpoRef surfaces were effective in inhibiting biofilm formation at initial stages (until day 28), while SilRef surfaces showed high efficacy in decreasing biofilm formation during maturation (from day 35 onwards). Wet weight and thickness analysis, as well as CLSM data, indicate that SilRef surfaces were less prone to biofilm formation than EpoRef surfaces. Furthermore, the efficacy of SilRef surfaces may be dependent on the fouling microorganism, while the performance of EpoRef was strongly influenced by a combined effect of surface and microorganism.This research was funded by Base Funding - UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology, and Energy - LEPABE - funded by national funds through the FCT/MCTES (PIDDAC), “CVMAR+i - Industrial Innovation and Marine Biotechnology Valorization” project, funded by INTERREG V Espanha Portugal (POCTEP) (0302_CVMAR_I_1_P), and UIDB/04423/2020 and UIDP/04423/2020 (CIIMAR). The research work was also supported by UIDB/04046/2020 and UIDP/04046/2020 research units grants, Portugal (to BioISI). R.T.-S. thanks the receipt of a junior researcher fellowship from the Project PTDC/BII-BIO/29589/2017 POCI-01-0145-FEDER-029589 funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES. L.C.G. thanks the Portuguese Foundation for Science and Technology (FCT) for the financial support of her work contract through the Scientific Employment Stimulus-Individual Call-[CEECIND/01700/2017]. Atomic force microscopy technique was performed at the Biointerface and Nanotechnology i3S Scientific Platform with the assistance of Manuela Brás

    One step forward towards the development of eco-friendly antifouling coatings: Immobilization of a sulfated marine-inspired compound

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    Marine biofouling represents a global economic and ecological challenge and few eco-friendly antifouling agents are available. The aim of this work was to establish the proof of concept that a recently synthesized nature-inspired compound (gallic acid persulfate, GAP) can act as an eco-friendly and effective antifoulant when immobilized in coatings through a non-release strategy, promoting a long-lasting antifouling effect. The synthesis of GAP was optimized to provide quantitative yields. GAP water solubility was assessed, showing values higher than 1000 mg/mL. GAP was found to be stable in sterilized natural seawater with a half-life (DT50) of 7 months. GAP was immobilized into several commercial coatings, exhibiting high compatibility with different polymeric matrices. Leaching assays of polydimethylsiloxane and polyurethane-based marine coatings containing GAP confirmed that the chemical immobilization of GAP was successful, since releases up to fivefold lower than the conventional releasing systems of polyurethane-based marine coatings were observed. Furthermore, coatings containing immobilized GAP exhibited the most auspicious anti-settlement effect against Mytilus galloprovincialis larvae for the maximum exposure period (40 h) in laboratory trials. Overall, GAP promises to be an agent capable of improving the antifouling activity of several commercial marine coatings with desirable environmental properties.This research was funded by national funds through the Foundation for Science and Technology (FCT) within the scope of research unit grants to CIIMAR (UIDB/04423/2020 and UIDP/04423/2020), to BioISI (UIDB/04046/2020 and UIDP/04046/2020) and under the project PTDC/AAG-TEC/0739/2014 (reference POCI-01-0145-FEDER-016793) supported through national funds provided by FCT and the European Regional Development Fund (ERDF) via the Programa Operacional Factores de Competitividade (POFC/COMPETE) programme and the Reforçar a Investigação, o Desenvolvimento Tecnológico e a Inovação (RIDTI; project 9471)

    Semi-automatic rubble counting system for superheated droplet detectors

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    Neutron dose rate measurements are normally performed by means of PADC, CR-39 and TLD detectors. Although, none of these devices can give instant reading of the neutron dose, recently new kind of detectors are being developed, based on the formation of tiny drops in a superheated liquid suspended in a polymer or gel solution, called superheated droplet detector (SDD) or also as bubble detectors (BD), with no response for gamma radiation. This work describes the experimental setup and the developed procedures for acquiring and processing digital images obtained with bubble detector spectrometer (BDS), developed by Bubble Technology Industries, for personal neutron dosimeter and/or neutron energy fluence measurements in nuclear facilities. The results of the neutron measurements obtained during the F-18 production, at the RDS-111 cyclotron, are presented. These neutron measurements were the first ones with this type of BDS detectors in a particle accelerator facility in Brazil and it was very important to estimate neutron dose rate received by occupationally exposed individuals

    Lagochilascariasis leading to severe involvement of ocular globes, ears and meninges

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    A case report of a 31 year-old woman from Paraíba State (North-Eastern Brazil) that presented severe involvement of ocular globes, ears and meninges. Diagnosis was established after enucleation of her left eye, when adult worms were seen in the midst of a granulomatous inflammatory process. Her response to the initial treatment with levamisole and cambendazole was good, but there was a relapse after the fifth month of treatment even with maintenance doses of both medications. She later received ivermectin and albendazol and responded well.Paciente do sexo feminino, com 31 anos, procedente da Paraíba, apresentava envolvimento severo de ambos os globos oculares, com perda da visão à esquerda, comprometimento da audição e das meninges. Após enucleação do olho esquerdo fragmento de helminto identificado como Lagochilascaris minor foi observado em processo inflamatório granulomatoso. Inicialmente a paciente foi tratada com levamisol e cambendazol, com bom resultado. Verificou-se, todavia, piora do quadro após cinco meses, com eliminação de larvas do ascarídeo em lesão presente na órbita esquerda, embora a medicação fosse mantida com administração periódica. Houve boa resposta terapêutica, com regressão do quadro, após substituição dos anti-helmínticos anteriores pela associação ivermectina e albendazol

    Dark energy, non-minimal couplings and the origin of cosmic magnetic fields

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    In this work we consider the most general electromagnetic theory in curved space-time leading to linear second order differential equations, including non-minimal couplings to the space-time curvature. We assume the presence of a temporal electromagnetic background whose energy density plays the role of dark energy, as has been recently suggested. Imposing the consistency of the theory in the weak-field limit, we show that it reduces to standard electromagnetism in the presence of an effective electromagnetic current which is generated by the momentum density of the matter/energy distribution, even for neutral sources. This implies that in the presence of dark energy, the motion of large-scale structures generates magnetic fields. Estimates of the present amplitude of the generated seed fields for typical spiral galaxies could reach 10910^{-9} G without any amplification. In the case of compact rotating objects, the theory predicts their magnetic moments to be related to their angular momenta in the way suggested by the so called Schuster-Blackett conjecture.Comment: 5 pages, no figure

    Clinical And Morphological Evolution Of The Induced Experimental Arthritis In Rattus Novergicus Albinus

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    The models of experimental arthritis become important in the inquiry of different therapeutical alternatives and briefing of articulate pathogenesis. The possibility of measuring the injury of the articular cartilage makes the experimental model relevantly important, as well as the systemic biological effects that involve the different therapeutics: The radiological and histological aspects of the cartilage were researched in the model of Zynoman-induced arthritis in Rattus novergicus. Rats were submitted to the intra-articular injection (1.0ml) and sacrificed at different times, under anesthesia. The knee joints were surgically removed and processed for coloring in hematoxylin eosin (H&E). The radiographic analyses were carried out through images obtained with dental periapical film. The animals presented serious and gradual synovitis associated to the injury of the cartilage that was evaluated up to 14 days after the stimulation injection. The arthritis model by Zymosan allows the study of the inflammatory alteration of the synovial tissue and of the cartilage. In the presence of Zymosan, the juxtarticular and periarticular tissues develop similar alterations to those found in the autoimmune diseases.2427581Arnett, F.C., Edworthy, S.M., Bloch, D.A., McShane, D.J., Fries, J.F., Cooper, N.S., The American Rheumatism Association 1987 revised criteria for classification of rheumatoid arthritis (1988) Arthritis Rheum, 31, pp. 315-324Brahn, E., Animal models of rheumatoid arthritis: Clues to etiology and treatment (1991) Clin Orthop, 265, pp. 42-53Bernotiene, E., Palmer, G., Talabot-Ayer, D., Quinodoz, I.S., Aubert, M.L., Gabay, C., Delayed resolution of acute inflammation during zymosaninduced in leptin-deficient mice. 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    "high Doses Of Riboflavin And The Elimination Of Dietary Red Meat Promote The Recovery Of Some Motor Functions In Parkinson's Disease Patients. C.g. Coimbra And V.b.c. Junqueira. Brazilian Journal Of Medical And Biological Research, 36: 1409-1417, 2003"

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    [No abstract available]37912971299Coimbra, C.G., Junqueira, V.B.C., High doses of riboflavin and the elimination of dietary red meat promote the recovery of some motor functions in Parkinson's disease patients (2003) Brazilian Journal of Medical and Biological Research, 36, pp. 1409-1417Pare, S., Burr, S.I., Ross, S.E., Effect of day-time protein restriction on nutrient intakes of free-living Parkinson's disease patients (1992) American Journal of Clinical Nutrition, 55, pp. 701-707Simon, N., Gantcheva, R., Bruguerolle, B., Viallet, F., The effects of a normal protein diet on levodopa plasma kinetics in advanced Parkinson's disease (2004) Parkinsonism and Related Disorders, 10, pp. 137-142Fahn, S., Elton, R.L., Unified Parkinson's Disease Rating Scale (1987) Recent Developments in Parkinson's Disease, 2, pp. 153-164. , Members of the UPDRS Development Committee Fahn S, Marsden CD, Calne DB & Goldstein M (Editors), MacMillan Health Care Information, Florham Park, NJ, USABaldereschi, M., DiCarlo, A., Vanni, P., Ghetti, A., Carbonin, P., Amaducci, L., Inzitani, D., Italian longitudinal study on aging working group. Lifestyle related risk factors for Parkinson's disease: A populational study (2003) Acta Neurologica Scandinavica, 108, pp. 239-244Tsai, C.H., Lo, S.K., See, L.C., Chen, H.Z., Chen, R.S., Weng, Y.H., Chang, F.C., Lu, C.S., Environmental risk factors of young onset Parkinson's disease (2002) Clinical Neurology and Neurosurgery, 104, pp. 328-333Tanner, C.M., Epidemiological clues to the cause of Parkinson's disease (1994) Movement Disorders 3, pp. 124-146. , Marsden CD & Fahn S (Editors) Butterworth-Heinemann, Oxford, UKGolbe, L.I., Farrel, T.M., Davis, P.H., Case-control study of early life dietary factors in Parkinson's disease (1988) Archives of Neurology, 45, pp. 350-353Abbot, R.D., Ross, G.W., White, C.R., Sanderson, W.T., Burchfiel, C.M., Kashon, M., Sharp, D.S., Petrovitch, H., Environment, lifestyle, and physical precursors of clinical Parkinson's disease: Recent findings from the Honolulu-Asia aging study (2003) Journal of Neurology, 250 (SUPPL. 3), pp. III30-III3
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