123 research outputs found

    Functional mobile-based two-factor authentication by photonic physical unclonable functions

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    Given the rapid expansion of the Internet of Things and because of the concerns around counterfeited goods, secure and resilient cryptographic systems are in high demand. Due to the development of digital ecosystems, mobile applications for transactions require fast and reliable methods to generate secure cryptographic keys, such as Physical Unclonable Functions (PUFs). We demonstrate a compact and reliable photonic PUF device able to be applied in mobile-based authentication. A miniaturized, energy-efficient, and low-cost token was forged of flexible luminescent organic–inorganic hybrid materials doped with lanthanides, displaying unique challenge–response pairs (CRPs) for two-factor authentication. Under laser irradiation in the red spectral region, a speckle pattern is attained and accessed through conventional charge-coupled cameras, and under ultraviolet light-emitting diodes, it displays a luminescent pattern accessed through hyperspectral imaging and converted to a random intensity-based pattern, ensuring the two-factor authentication. This methodology features the use of a discrete cosine transform to enable a low-cost and semi-compact encryption system suited for speckle and luminescence-based CRPs. The PUF evaluation and the authentication protocol required the analysis of multiple CRPs from different tokens, establishing an optimal cryptographic key size (128 bits) and an optimal decision threshold level that minimizes the error probability.publishe

    RG108 increases NANOG and OCT4 in bone marrow-derived mesenchymal cells through global changes in DNA modifications and epigenetic activation. RG108 increases NANOG and OCT4 through epigenetic activation.

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    Human bone marrow-derived mesenchymal stem cells (hBMSCs) are important for tissue regeneration but their epigenetic regulation is not well understood. Here we investigate the ability of a non-nucleoside DNA methylation inhibitor, RG108 to induce epigenetic changes at both global and gene-specific levels in order to enhance mesenchymal cell markers, in hBMSCs. hBMSCs were treated with complete culture medium, 50 μM RG108 and DMSO for three days and subjected to viability and apoptosis assays, global and gene-specific methylation/hydroxymethylation, transcript levels' analysis of epigenetic machinery enzymes and multipotency markers, protein activities of DNMTs and TETs, immunofluorescence staining and western blot analysis for NANOG and OCT4 and flow cytometry for CD105. The RG108, when used at 50 μM, did not affect the viability, apoptosis and proliferation rates of hBMSCs or hydroxymethylation global levels while leading to 75% decrease in DNMTs activity and 42% loss of global DNA methylation levels. In addition, DNMT1 was significantly downregulated while TET1 was upregulated, potentially contributing to the substantial loss of methylation observed. Most importantly, the mesenchymal cell markers CD105, NANOG and OCT4 were upregulated being NANOG and OCT4 epigenetically modulated by RG108, at their gene promoters. We propose that RG108 could be used for epigenetic modulation, promoting epigenetic activation of NANOG and OCT4, without affecting the viability of hBMSCs. DMSO can be considered a modulator of epigenetic machinery enzymes, although with milder effect compared to RG108

    The effect of salts on the liquid–liquid phase equilibria of PEG600 + salt aqueous two-phase systems

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    Six new ATPSs were prepared by combining polyethylene glycol PEG600 with potassium citrate, dipotassium hydrogen phosphate, sodium formate, potassium formate, sodium sulfate, and lithium sulfate. Complete phase diagrams, including the binodal curve and three tie-lines, were determined at 23 °C. The experimental data obtained for the binodal curve were successfully adjusted to the Merchuk equation, and the reliability of tie-line data was confirmed using the equations suggested by Othmer–Tobias and Bancroft. The ability of each ion to induce ATPS formation was investigated. Na+ proved to be more effective in ATPS formation than K+ and Li+. For potassium salts, the order observed for the effectiveness of the anions was: HPO42– > C6H5O73– > HCO2–. Regarding the sodium salts, it was found that SO42– is clearly more effective than HCO2–. The position of the ions in the Hofmeister series and their free energy of hydration (ΔGhyd) were used to explain the ability of the ions to induce PEG salting-out. Furthermore, the effective excluded volume (EEV) of the salts was determined and the following order was found: Na2SO4 > K2HPO4 > Li2SO4 > K3C6H5O7 > NaCHO2 > KCHO2. Similar order was obtained when analyzing the size of the heterogeneous regions, suggesting the practical use of EEV as a comparison parameter between different ATPSs.This work is partially supported by project PEst-C/EQB/LA0020/2011, financed by FEDER through COMPETE-Programa Operacional Factores de Competitividade and by FCT-Fundacao para a Ciencia e a Tecnologia. Sara Silverio acknowledges her Ph.D. grant from FCT (SFRH/BD/43439/2008)

    Bis(tetra­phenyl­phospho­nium) bis­[N-(phenyl­sulfon­yl)dithio­carbimato-κ2 S,S′]platinate(II) monohydrate

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    The asymmetric unit of the title compound, (C24H20P)2[Pt(C7H5NO2S3)2]·H2O, consists of two tetra­phenyl­phospho­nium cations, two half bis­[N-(phenyl­sulfon­yl)dithio­carbim­ato]platinate(II) dianions and one water mol­ecule. The anions are completed by crystallographic inversion symmetry associated with the central PtII ion. The PtII ion is doubly S,S′-chelated by two symmetry-related phenyl­sulfonyl­dithio­carbimate ligands, forming a slightly distorted square-planar configuration. Besides the electrostatic attraction between oppositely charged ions in the crystal packing, intra­molecular C—H⋯O and several inter­molecular C—H⋯O, C—H⋯N and O—H⋯O hydrogen-bonding inter­actions between the cations, anions and water mol­ecules are observed

    Aplicação de marcadores moleculares na conservação e melhoramento de um rebanho da raça Santa Inês.

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    0 objetivo deste trabalho foi caracterizar a distribuiçao da variabilidade genetica dentro de um Nucleo de Conservaçao da raça Santa Ines a partir do usa de marcadores moleculares. Foram utilizados 17 locos em 191 individuos do rebanho de Santa Ines da Embrapa Tabuleiros Costeiros, Sergipe. Os resultados obtidos mostraram que existe variabilidade genetica significativa existente dentro do nucleo com valores de Heterezigosidade media observada de 0,702 e de conteudo de informaçao polimorfica (PIC) de 0,704. Outras analises intrapopulacionais mostraram que 29% dos locos analisados nao estao em Equilfbrio de Hardy-Weinberg (p<0,01) e apresentaram excesso de homozigotos (p<0,05). A partir do fndice de proporçao de alelos compartilhados entre todos os individuos analisados, foi feito um dendrograma para estimar quais seriam os animais mais proximos ou mais distantes dentro do rebanho, com especial atençao para os 10 machos reprodutores. Tres agrupamentos principais foram identificados e em todos existe pelo menos um reprodutor do rebanho. Esse tipo de analise e importante, pais ira auxiliar o manejo reprodutivo do rebanho bem com servira de ferramenta complementar para os programas de melhoramento classico que se iniciaram dentro deste Nucleo de Conservaçao

    Sex and body mass index impact on digit circumference for Leeds Dactylitis Index calculation

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    Objectives: To estimate digit circumference and the impact of sex and body mass index (BMI) for the calculation of the Leeds Dactylitis Index (LDI) in psoriatic arthritis (PsA) patients with bilateral dactylitis. Methods: Digit circumference of the hands and the foot were measured with a dactylometer and were studied according to sex and BMI (divided in 4 weight categories) in healthy Portuguese subjects, using Student's t-test and One-way ANOVA, respectively. The effect size of sex and BMI were calculated using Cohen's d test and Eta squared, respectively. Multiple linear regression was used to calculate the effect of sex and BMI, as well as their interaction, to create a formula to predict digit circumference. Results: Fifty-nine participants (33 women, 26 men) with a mean BMI of 24.8 were included. Men's mean digit circumferences were statistically higher than those of women (p<0.001), with a large sex effect size in most of the digits. Differences in the mean circumference between the four BMI categories were statistically significant (p<0.05) for all digits, with a large BMI effect size. Sex and BMI were independent variables to predict mean digit circumference (p<0.001). A new tool (based on regression analysis) allowing to estimate the circumference of digits for males and females of different BMIs is presented. Conclusions: Our data allows the calculation of digit circumference for males and females of different BMIs in the Portuguese population; and shows that BMI influences digital circumference supporting BMI inclusion in LDI references tablesinfo:eu-repo/semantics/publishedVersio

    Portuguese recommendations for the use of biological and targeted synthetic diseasemodifying antirheumatic drugs in patients with rheumatoid arthritis – 2020 update

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    Objective: To update the recommendations for the treatment of rheumatoid arthritis (RA) with biological and targeted synthetic disease-modifying antirheumatic drugs (bDMARDs and tsDMARDs), endorsed by the Portuguese Society of Rheumatology (SPR). Methods: These treatment recommendations were formulated by Portuguese rheumatologists taking into account previous recommendations, new literature evidence and consensus opinion. At a national meeting, in a virtual format, three of the ten previous recommendations were re-addressed and discussed after a more focused literature review. A first draft of the updated recommendations was elaborated by a team of SPR rheumatologists from the SPR rheumatoid arthritis study group, GEAR. The resulting document circulated among all SPR rheumatologists for discussion and input. The level of agreement with each of all the recommendations was anonymously voted online by all SPR rheumatologists. Results: These recommendations cover general aspects such as shared decision, treatment objectives, systematic assessment of disease activity and burden and its registry in Reuma.pt. Consensus was also achieved regarding specific aspects such as initiation of bDMARDs and tsDMARDs, assessment of treatment response, switching and definition of persistent remission. Conclusion: These recommendations may be used for guidance of treatment with bDMARDs and tsDMARDs in patients with RA. As more evidence becomes available and more therapies are licensed, these recommendations will be updated.info:eu-repo/semantics/publishedVersio

    AVALIAÇÃO DA INFLUÊNCIA DA VARIABILIDADE DE ÓLEOS NO MICROENCAPSULAMENTO DE FÁRMACOS HIDROFÍLICOS DE BAIXO PESO MOLECULAR POR EMULSIFICAÇÃO A/O

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    A obtenção de micropartículas por técnicas de emulsificação assumiu grande relevância para o microencapsulamento de fármacos hidrofílicos. O trabalho avalia o uso de diferentes óleos vegetais para o processo de obtenção de micropartículas por emulsificação a/o e observa sua influência no encapsulamento de fármacos de baixo peso molecular

    Thermal and mechanical properties of chitosan nanocomposites with cellulose modified in ionic liquids

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    In this paper, ionic liquid treatment was applied to produce nanometric cellulose particles of two polymorphic forms. A complex characterization of nanofillers including wide-angle X-ray scattering, Fourier transform infrared spectroscopy, and particle size determination was performed. The evaluated ionic liquid treatment was effective in terms of nanocrystalline cellulose production, leaving chemical and supermolecular structure of the materials intact. However, nanocrystalline cellulose II was found to be more prone to ionic liquid hydrolysis leading to formation larger amount of small particles. Each nanocrystalline cellulose was subsequently mixed with a solution of chitosan, so that composite films containing 1, 3, and 5% mass/mass of nanometric filler were obtained. Reference samples of chitosan and chitosan with micrometric celluloses were also solvent casted. Thermal, mechanical, and morphological properties of films were tested and correlated with properties of filler used. The results of both, tensile tests and thermogravimetric analysis showed a significant discrepancy between composites filled with nanocrystalline cellulose I and nanocrystalline cellulose II
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