6,211 research outputs found

    Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-induced tautomerization in argon matrix

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    The prototropic tautomerism in 3(5)-aminopyrazoles was investigated by matrix isolation infrared (IR) spectroscopy, supported by DFT(B3LYP)/6-311++G(d,p) calculations. In consonance with the experimental data, the calculations predict tautomer 3-aminopyrazole (3AP) to be more stable than the 5-aminopyrazole (5AP) tautomer (calculated energy difference: 10.7 kJ mol−1 ; Gibbs free energy difference: 9.8 kJ mol−1 ). The obtained matrix isolation IR spectra (in both argon and xenon matrices) were interpreted, and the observed bands were assigned to the tautomeric forms with help of vibrational calculations carried out at both harmonic and anharmonic levels. The matrix-isolated compound (in argon matrix) was then subjected to in situ broadband UV irradiation (λ > 235 nm), and the UV-induced transformations were followed by IR spectroscopy. Phototautomerization of the 3AP tautomer into the 5AP form was observed as the strongly prevalent reaction.UI0313B/QUI/2020, UI0313P/QUI/2020info:eu-repo/semantics/publishedVersio

    On the Richardson-Lucy Algorithm with A Varying Point Spread Function along The Iterations

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    Abstract: This work analyses the soundness of two algorithms, Fishsint and Almexp to improve images using the Richardson-Lucy (RL) algorithm under a varying Point Spread Function (PSF) along the iterations. A plethora of methods based on Richardson-Lucy has been published, but no further proposal involving such an alternative has been published. Whereas the unnamed predecessor of Fishsint addressed only small size synthetic images under a blind fashion procedure, Fishsint and Almexp employs an algorithm Wdet to determine the initial PSF and all subsequent values after each iteration, respectively. Fishsint performs a loop, where the last determined PSF improves the previously obtained image and vice versa. Its original unnamed version has been modified in the present work by entering a previously determined initial PSF to accelerate the convergence. The algorithm Almexp, as well, uses the algorithm Wdet to determine the PSF of the last obtained image to deconvolve itself. Therefore, whereas the Fishsint unnamed predecessor used an initial guess PSF - chosen by the customer - Almexp determines the PSF always through the algorithm Wdet. Fishsint and Almexp furnish final images which outperform those obtained with the original Richardson-Lucy approach working under a constant PSF along the iterations. Hence, in order to carry out a comparison between their performances, all the algorithms have been embedded into an ad hoc written Fortran 90 program. The results corroborate the soundness of a varying PSF along the iterations with the Richardson Lucy algorithm. Keywords: Richardson-Lucy, varying PSF along iterations, image improvement, neutron radiograph

    Técnicas de Análise Espacial Aplicadas à Caracterização da População Idosa para Planear Cuidados de Enfermagem

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    O estudo aponta uma metodologia para caracterizar factores geodemográficos condicionantes da acessibilidade geográfica a cuidados de enfermagem, numa das regiões mais envelhecidas de Portugal, a partir do uso de Sistemas de Informação Geográfica. Analisam-se dados provenientes dos censos de população relativos aos idosos. Métodos: Utilizam-se técnicas de estatística espacial, para além das técnicas de estatística clássica. Estuda-se a autocorrelação espacial dos valores de alguns índices demográficos, caracterizando estatisticamente a existência de aglomerados na zona de estudo, recorrendo ao Índice Global de Moran. Igualmente caracteriza-se a concentração de valores elevados e de valores baixos para cada um dos índices, recorrendo ao cálculo da estatística GI*. Resultados: Identificam-se as regiões de maior envelhecimento, aquelas onde se perspectiva a maior utilização de recursos de Enfermagem por parte dos idosos. Conclusões: O estudo faz apelo à necessária gestão programática dos recursos materiais e humanos de enfermagem, perspectivando a minimização dos efeitos que a situação geodemográfica heterogénea condiciona

    Dendrimers in tissue engineering

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    Dendrimers are highly branched and multivalent, and monodispersive making them perfect candidates for a myriad of controlled drug delivery applications. Dendrimers possess many other advantages, such as the possibility of modulating surface chemistry and charge, and biodegradation rate and to be processed as scaffolds that can emulate natural extracellular matrices thus opening up unique applications in tissue engineering. The combination of dendrimers and other macromolecules (proteins and carbohydrates), as well as other traditional scaffold polymers, has led to the creation of hybrid scaffolds with new physical, mechanical, and biochemical properties. However, despite the widespread use of dendrimers in biomedical applications, their use in the fabrication of tissue engineering scaffolds remains some-how narrow. The most promising applications of dendritic macromolecules in TE area such as drug delivery strategies, cell differentiation and/or tissue regeneration, 3D/Dynamic platforms and ex vivo/in vivo testing are overviewed and discussed herein.JMO for the financial support provided under the program “Investigador FCT” (IF/01285/2015). MCR acknowledges the IET Institution of Engineering and Technology for the financial support provided under the IET Harvey Research Prize 2017. IMO thanks the financial support under the Norte2020 project (“NORTE-08-5369-FSE-000044”)

    Isolation of phytopathogenic fungi in seeds Caatinga tree

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    A qualidade sanitária é um parâmetro que avalia a incidência de patógenos em sementes, principalmente em espécies de produção agrícola, havendo poucos estudos sobre espécies florestais arbóreas. O presente trabalho tem como objetivo avaliar a qualidade sanitária em sementes de espécies arbóreas da Caatinga. O experimento foi conduzido no Laboratório de Fitopatologia do Centro de Ciências e Tecnologia Agroalimentar da UFCG, campus de Pombal-PB. Foram estudadas sementes de quatro espécies arbóreas: Myracrodruon urundeuva (Allemão): aroeira, Poincianella pyramidalis (Tul.): catingueira, Mimosa tenuiflora (Willd.)Poiret: jurema-preta e Libidibia ferrea (Mart) ex Tul.: pau-ferro, as mesmas foram divididas em duas subamostras, sendo uma submetida à desinfestação superficial por imersão em hipoclorito de sódio (NaClO) a 2% por 5 minutos . A sanidade das sementes foi avaliada pelo “blotter test”. Os gêneros fúngicos comumente detectados nas sementes das espécies estudadas foram: Aspergillus spp., Cladosporium spp., Fusarium spp., Penicillium spp. e Trichoderma spp.. A desinfestação com hipoclorito de sódio a 2% reduziu a incidência de fungos nas sementes das espécies estudadas. O gênero Aspergillus apresentou o maior número de colônias e diversidade de espécies fúngicas nas sementes tratadas e não tratadas, estando presente em todas as espécies arbóreas. A menor incidência de colônias fúngicas ocorreu na espécie Mimosa tenuiflora.The sanitary quality is a parameter that evaluates the incidence of pathogens in seeds, especially in species of agricultural production, so that there are few studies on forest tree species. This study aims to evaluate the sanitary quality and the effect on seeds of four species from the Caatinga region. The experiment was conducted at the Laboratory of Phytopathology from the Centre for Agri-Food Science and Technology at UFCG, Pombal - PB. Seeds from four species were studied: Myracrodruon urundeuva (Allemão): aroeira, Poincianella pyramidalis (Tul.) L.P. Queiroz: catingueira, Mimosa tenuiflora (Willd.) Poiret: jurema-preta and Libidibia ferrea (Mart ex Tul.) L.P. Queiroz: pau-ferro. The seed health was assessed using the “blotter test”. The genera of fungi commonly found in the seeds of the studied species were Aspergillus spp., Cladosporium spp., Fusarium spp., Penicillium spp. and Trichoderma spp. The disinfection with 2% sodium hypochlorite reduced the incidence of fungi on seeds of the studied species. The genus Aspergillus presented the highest number of colonies and diversity of fungal species in treated and untreated seeds, being present in all four species. The lowest incidence of fungal colonies occurred in the species Mimosa tenuiflora.Facultad de Ciencias Agrarias y Forestale

    A Retrospective Cohort Study

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    Purpose Graves' disease (GD) is an autoimmune disorder caused by the presence of antibodies to the thyroid stimulating hormone (TSH) receptor (TRAbs), usually presenting with clinical signs of hyperthyroidism. Previous evidence suggests that higher serum levels of thyroid peroxidase antibodies (TPOAbs) may lead to more sustained remission of hyperthyroidism after treatment with antithyroid drugs (AT). However, doubts about the influence of TPOAbs in Graves' disease outcomes still remain. Methods A retrospective, unicenter cohort study was performed. All patients with GD (TRAbs > 1.58U/L), biochemical primary hyperthyroidism (TSH < 0.4 µUI/mL), and TPOAbs measurement at diagnosis, treated with AT between January 2008 and January 2021, were included for analysis. Results One hundred and forty-two patients (113 women) with a mean age of 52 ± 15 years old were included. They were followed up for 65.4 ± 43.8 months. TPOAbs positivity was present in 71.10% (n=101) of those patients. Patients were treated with AT for a median of 18 (IQR (12; 24)) months. Remission occurred in 47.2% of patients. Patients with remission presented with lower TRAbs and free thyroxine (FT4) levels at the diagnosis. (p-value <0.001, p-value 0.003, respectively). No association was found in the median TPOAbs serum levels of patients who remitted and those who maintained biochemical hyperthyroidism after the first course of AT. Relapse of hyperthyroidism occurred in 54 patients (57.4%). No difference was found in TPOAbs serum levels regarding the patient's relapse. Moreover, a time-based analysis revealed no differences in the relapse rate after 18 months of AT therapy between patients with and without TPOAbs positivity at the diagnosis (p-value 0.176). It was found a weak positive correlation (r=0.295; p-value <0.05) between TRAbs and TPOAbs titters at the moment of Graves' diagnosis. Conclusion In this study, a correlation between TRAbs measurements and TPOAbs titter was described, although no significant association was found between the presence of TPOAbs and the outcomes of patients with GD treated with AT. These results do not support the use of TPOAbs as a useful biomarker to predict remission or relapse of hyperthyroidism in GD patients.publishersversionpublishe

    First-Principles Model to Evaluate Quantitatively the Long-Life Behavior of Cellulose Acetate Polymers

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    UIDB/04028/2020 UIDP/04028/2020 UID/QUI/50006/2019A deep understanding of the degradation of cellulose diacetate (CDA) polymer is crucial in finding the appropriate long-term stability solution. This work presents an investigation of the reaction mechanism of hydrolysis using electronic density functional theory calculations with the B3LYP/6-31++G*∗ level of theory to determine the energetics of the degradation reactions. This information was coupled with the transition-state theory to establish the kinetics of degradation for both the acid-catalyzed and noncatalyzed degradation pathways. In this model, the dependence on water concentration of the polymer as a function of pH and the evaporation of acetic acid from the polymer is explicitly accounted for. For the latter, the dependence of the concentration of acetic acid inside the films with the partial pressure on the surrounding environment was measured by sorption isotherms, where Henry's law constant was measured as a function of temperature. The accuracy of this approach was validated through comparison with experimental results of CDA-accelerated aging experiments. This model provides a step forward for the estimation of CDA degradation dependence on environmental conditions. From a broader perspective, this method can be translated to establish degradation models to predict the aging of other types of polymeric materials from first-principles calculations.publishersversionpublishe
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