Obtaining bioabsorable scaffolds from PLGA and IR blend with the addition of hydroxyapatite

A obtenção de scaffolds bioativos a partir da blenda polimérica de poli (ácido láctico-co-glicólico) (PLGA) e poliisopreno (IR) com diferentes adições de Hidroxiapatita (HAp) é proposta como uma alternativa à engenharia de tecidos. Para o preparo das soluções poliméricas, a blenda de PLGA/IR e a HAp foram dissolvidas em clorofórmio. Posteriormente, o scaffold foi processado por electrospinning, variando-se a distância entre a seringa e o coletor. As amostras foram caracterizadas quanto a composição química e estrutural por potencial zeta, difração de raios-X (DRX) e espectroscopia de infravermelho por transformada de Fourier (FTIR). Para avaliação da morfologia usou-se a microscopia eletrônica de varredura (MEV) e para o comportamento citotoxicológico utilizou-se a metodologia de analises de viabilidade celular. O valor de potencial zeta da HAp foi de -22 mV e o FTIR e DRX foram condizentes com a literatura. As imagens de MEV permitiram a análise do tamanho médio e desvio padrão das fibras obtidas, comprovando uma diferença significativa entre as amostras. O ensaio de citotoxicidade mostrou que o produto obtido é biocompatível, porém as amostras com menor formação de fibras são menos biocompatíveis. Os resultados demonstraram a ampla influência da distância entre o coletor e a ponta da seringa e da relação blenda/HAp, sendo que o scaffold obtido com a maior distância coletor/seringa e maior relação HAp/blenda apresentou fibras com tamanho médio menores e maior homogeneidade e baixa citotoxicidade celular.The aim of this paper is the obtainment of bioactive scaffolds from poly (lactic acid-co-glycolic acid) (PLGA) and polyisoprene (IR) polymer blends with different additions of hydroxyapatite (HAp) as an alternative for tissue engineering. For the preparation of the polymer solutions, the PLGA/IR blend and the HAp were dissolved in chloroform. Subsequently, the scaffold was processed by electrospinning, varying the distance between the syringe and the collector. Scaffolds chemical and phase composition were characterized by zeta potential, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was used to evaluate the morphology and for the cytotoxic behavior the cellular viability analysis methodology was used. The zeta potential value of the HAp was -22 mV and the FTIR and XRD were consistent with the literature. The SEM images allowed the analysis of the mean size and standard deviation of the obtained fibers, demonstrating a significant difference among the samples. The results showed the great influence of the distance between the collector and the tip of the syringe and the blend/HAp ratio, and the scaffold obtained with the largest collector/ syringe distance and the highest HAp/blend ratio showed fibers with a smaller mean size and greater homogeneity and low cellular cytotoxicity

A ambientalização curricular e suas contribuições para formação acadêmica

O presente estudo revela parte de resultados de uma pesquisa de mestrado em andamento que busca compreender o processo de ambientalização e suas contribuições para a formação profissional em nossas universidades. A inserção da Educação Ambiental na Educação Superior, por meio do processo de ambientalização, caracteriza-se como um potente aliado ao bem viver comum, uma vez que pelo que é defendido neste estudo, o referido processo possibilita uma reflexão ética e moral na formação acadêmica, sobre as complexas relações consigo mesmo, com o outro, com as outras espécies e com o meio ambiente de forma transversal, permanente e contínua

Fundamental parameters related to selenium kα and kβ emission x-ray spectra

This research was funded in part by FCT (Portugal) under research center grants UID/FIS/04559/2020 (LIBPhys) and UID/MULTI/04046/2020 (BioISI). This work was also funded through the project PTDC/FIS-AQM/31969/2017, "Ultra-high-accuracy x-ray spectroscopy of transition metal oxides and rare earths." J.M. and J.P.S acknowledge the support of EMPIR, under Contract No. 17FUN02MetroMMC. The EMPIR initiative is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR participating States.We present relativistic ab initio calculations of fundamental parameters for atomic selenium, based on the Multiconfiguration Dirac-Fock method. In detail, fluorescence yields and subshell linewidths, both of K shell, as well as Kβ to Kα intensity ratio are provided, showing overall agreement with previous theoretical calculations and experimental values. Relative intensities were evaluated assuming the same ionization cross-section for the K-shell hole states, leading to a statistical distribution of these initial states. A method for estimating theoretical linewidths of X-ray lines, where the lines are composed by a multiplet of fine-structure levels that are spread in energy, is proposed. This method provides results that are closer to Kα1,2 experimental width values than the usual method, although slightly higher discrepancies occur for the Kβ1,3 lines. This indicates some inaccuracies in the calculation of Auger rates that have a higher contribution for partial linewidths of the subshells involved in the Kβ1,3 profile. Apart from this, the calculated value of Kβ to Kα intensity ratio, which is less sensitive to Auger rates issues, is in excellent agreement with recommended values.publishersversionpublishe

Investigação cinética da pirólise de biomassa amazônica por termogravimetria / Kinetic investigation of amazon biomass pyrolysis by thermogravimetry

A energia presente na biomassa pode ser aproveitada através de processos de conversão que a transformam em combustíveis líquidos, sólidos e gasosos. O Brasil apresenta grandes dimensões cultiváveis de biomassas agrícolas e florestais que geram grande quantidade de resíduos e podem ser utilizados para a geração de energia. Este trabalho teve como objetivo investigar o comportamento térmico e realizar o estudo cinético da pirólise de biomassa amazônica in natura e torrada através de uma série de ensaios de análise imediata e termogravimétrica em atmosfera não oxidante em diversas taxas de aquecimento: 5, 10, 20 e 30 K/min. As curvas termogravimétricas foram submetidas à avaliação cinética por métodos dinâmicos. Verificou-se as três estapas da pirolise de biomassas lignocelulósica: remoção da água, pirólise ativa e pirolise passiva. Na etapa considerada de pirólise ativa, a energia de ativação e o fator pré-exponencial variaram com a conversão de massa para os modelos cinéticos considerados. Os parâmetros cinéticos foram determinados pelos métodos: Kissinger, Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) e Friedman. O processo de volatização foi matematicamente descrito por uma reação de primeira ordem

K- and L-shell theoretical fluorescence yields for the Fe isonuclear sequence

Funding Information: This research was funded in part by FCT (Portugal) under research center grant UID/FIS/04559/2020 (LIBPhys). This work was also funded through the project PTDC/FIS-AQM/31969/2017, “Ultra-high-accuracy X-ray spectroscopy of transition metal oxides and rare earths”. F.G. acknowledges support from FCT, Portugal through contract UI/BD/151000/2021 . J. M and J.P.S acknowledge the support of EMPIR, Germany , under Contract No. 20FUN04 PrimA-LTD. The EMPIR initiative is co-funded by the European Union’s Horizon 2020 research and innovation programme and the EMPIR, Germany participating States. Part of this work has been carried out under the High Performance Computing Chair - a R&D infrastructure (based at the University of Évora; PI: M. Avillez), endorsed by Hewlett Packard Enterprise (HPE), and involving a consortium of higher education institutions (University of Algarve, University of Évora, NOVA University Lisbon, and University of Porto), research centres (CIAC, CIDEHUS, CHRC), enterprises (HPE, ANIET, ASSIMAGRA, Cluster Portugal Mineral Resources, DECSIS, FastCompChem, GeoSense, GEOtek, Health Tech, Starkdata), and public/private organizations (Alentejo Tourism-ERT, KIPT Colab). Funding Information: This research was funded in part by FCT (Portugal) under research center grant UID/FIS/04559/2020 (LIBPhys). This work was also funded through the project PTDC/FIS-AQM/31969/2017, “Ultra-high-accuracy X-ray spectroscopy of transition metal oxides and rare earths”. F.G. acknowledges support from FCT, Portugal through contract UI/BD/151000/2021. J. M and J.P.S acknowledge the support of EMPIR, Germany, under Contract No. 20FUN04 PrimA-LTD. The EMPIR initiative is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR, Germany participating States. Part of this work has been carried out under the High Performance Computing Chair - a R&D infrastructure (based at the University of Évora; PI: M. Avillez), endorsed by Hewlett Packard Enterprise (HPE), and involving a consortium of higher education institutions (University of Algarve, University of Évora, NOVA University Lisbon, and University of Porto), research centres (CIAC, CIDEHUS, CHRC), enterprises (HPE, ANIET, ASSIMAGRA, Cluster Portugal Mineral Resources, DECSIS, FastCompChem, GeoSense, GEOtek, Health Tech, Starkdata), and public/private organizations (Alentejo Tourism-ERT, KIPT Colab). Publisher Copyright: © 2022 The Author(s)In this work, we present K- and L- shell fluorescence yield values of the full isonuclear sequence of Fe ions, using a state-of-the-art multiconfiguration Dirac–Fock approach. These results may be of importance for spectral fitting and plasma modeling, both in laboratory and astrophysical studies, where Fe is an important benchmark element. The K-shell fluorescence yields were found to be very similar up to the removal of 14 electrons.publishersversionpublishe

Structure of Kα1,2 - And Kβ1,3 -emission x-ray spectra for Se, Y, and Zr

UID/FIS/04559/2020 UID/MULTI/04046/2020 Project No. PTDC/FIS-AQM/31969/20 Grant No. 2017/25/B/ST2/00901The Kα and Kβ x-ray spectra of Se, Y, and Zr were studied experimentally and theoretically in order to obtain information on the Kα1 line asymmetry and the spin doublet in Kβ1,3 diagram lines. Using a high-resolution antiparallel double-crystal x-ray spectrometer, we obtained the line shapes, that is, asymmetry index and natural linewidths. We found that the corrected full width at half maximum of the Kα1 and Kα2 lines as a function of Z is in good agreement with the data in the literature. Furthermore, satellite lines arising from shake-off appear in the low-energy side of the Kα1 and Kα2 lines in Se but, in Y and Zr, it was very difficult to identify the contribution of the shake process to the overall lines. The Kβ1,3 natural linewidth of these elements was also corrected using the appropriate instrumental function for this type of x-ray spectrometer, and the spin doublet energies were obtained from the peak positions. The corrected full width at half maximum (FWHM) of the Kβ1 x-ray lines increases linearly with Z, but this tendency was found to be, in general, not linear for Kβ3 x-ray lines. This behavior may be due to the existence of satellite lines originated from shake processes. Simulated line profiles, obtained using the multiconfiguration Dirac-Fock formalism, accounting for radiative and radiationless transitions and shake-off processes, show a very good agreement with the high-resolution experimental spectra.publishersversionpublishe