954 research outputs found
A preliminary analysis on gender aspects in transport systems and mobility services: presentation of a survey design
As sustainability is becoming a common practice in planning transport systems and
mobility services, the designation and management of gender issues are of paramount importance. TInnGO is a European Project that has developed a network of 10 national Hubs to build the capacity to generate and apply evidence on gender equality and transport issues at the European level. This paper presents the project activities by introducing a relevant framework and exploring user mobility experiences based on gender to identify diversified needs and requirements. This process relies on the combination of a review of current gender-oriented experiences and practices in mobility with focus group activities conducted in four different EU cities. The insights obtained from these activities supported the design of a survey to collect information on socioeconomic, personal, and operational aspects to serve a gender-oriented transport analysis for all the Hubs. These preliminary analyses identified the main issues related to the female mobility experience, namely safety, security, accessibility, and transport reliability. Future research on the data collected through the survey would help operators in successfully improving their mobility offer to women.info:eu-repo/semantics/publishedVersio
Development of chitosan-gelatin nanofibers with cellulose nanocrystals for skin protection applications
In this work, natural-based and biodegradable nanofibers were produced by electrospinning for drug delivery and wound dressing applications, using gelatin (Gel), chitosan (CS), cellulose nanocrystals (CNC) and natural propolis extract. The polymeric formulations and electrospinning parameters were optimized, resulting in the development of Gel/CS nanofibers with mean diameters of 97 nm. CNC were successfully introduced into the optimized Gel/CS solution and the viscosity and conductivity values were recorded. The developed nanofibers were characterized using FESEM, ATR-FTIR, TGA and WCA. The incorporation of different CNC concentrations improved the solutions’ electrospinnability and the membranes’ physical integrity. Defect-free and uniform Gel/CS/CNC nanofibers were observed by FESEM images, and the fibers’ diameters slight increased. The hydrophilic character was maintained after the CNC incorporation. Finally, Gel/CS/CNC/Propolis nanofibers demonstrated antibacterial activity against both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteriaThe authors are thankful to TSSiPRO project, operation code NORTE01-0145-FEDER-000015.
The authors are also grateful to FCT, Portugal for financial support through national funds
FCT/MCTES to CIMO (UIDB/00690/2020) and to 2C2T (UID/CTM/00264/2019). D. P. Ferreira
thank the national funding by FCT through the individual scientific employment program-contract
(CEECIND/02803/2017) and S. M. Costa thank the FCT PhD Scholarship (SFRH/BD/147517/2019)
Fucoidan-based hydrogels particles as versatile carriers for diabetes treatment strategies
There is a current lack of fully efficient therapies for diabetes mel-litus, a chronic disease where the metabolism of blood glucose isseverely hindered by a deficit in insulin or cell resistance to thishormone. Therefore, it is crucial to develop new therapeutic strat-egies to treat this disease, including devices for the controlleddelivery of insulin or encapsulation of insulin-producing cells. Inthis work, fucoidan (Fu)â a marine sulfated polysaccharide exhib-iting relevant properties on reducing blood glucose and antioxi-dant and anti-inflammatory effectsâ was used for thedevelopment of versatile carriers envisaging diabetes advancedtherapies. Fu was functionalized by methacrylation (MFu) using8% and 12% (v/v) of methacrylic anhydride and further photo-crosslinked using visible light in the presence of triethanolamineand eosin-y to produce hydrogel particles. Degree of methacryla-tion varied between 2.78 and 6.50, as determined by1HNMR, andthe produced particles have an average diameter ranging from0.63 to 1.3mm (dry state). Insulin (5%) was added to MFu solutionto produce drug-loaded particles and the release profile wasassessed in phosphate buffer solution (PBS) and simulated intes-tinal fluid (SIF) for 24h. Insulin was released in a sustained man-ner during the initial 8 h, reaching then a plateau, higher in PBSthan in SIF, indicating that lower pH favors drug liberation.Moreover, the ability of MFu particles to serve as templates forthe culture of human pancreatic cells was assessed using 1.1B4cell line during up to 7 days. During the culture period studied,pancreatic beta cells were proliferating, with a global viabilityover 80% and tend to form pseudo-islets, thus suggesting thatthe proposed biomaterial could be a good candidate as versatilecarrier for diabetes treatment as they sustain the release of insulinand support pancreatic beta cells viability.We acknowledge ERDF for the financial support through POCTEP Project 0687_NOVOMAR_1_P, under the scope of INTERREG 2007-2013, and project 0302_CVMAR_I_1_P, under the scope of INTERREG Espana-Portugal 2014-2020, and Structured Projects NORTE-01-0145-FEDER-000021, NORTE-01-0145-FEDER-000023 and ATLANTIDA (ref. NORTE-01–0145-FEDER-000040), under the scope of Programa Operacional Regional do Norte (Norte 2020). Funding from the Portuguese Foundation for Science and Technology for doctoral grant (SFRH/BD/112139/2015) and post-doctoral grant (SFRH/BPD/85790/2012) is also acknowledge
Sugarcane straw polyphenols as potential food and nutraceutical ingredient
The sugarcane processing industry generates a large amount of straw, which has a negative environmental impact, and high costs are associated with their elimination, wasting their potential bioactive value attributed to their richness in polyphenols. In this study, an ethanolic extract produced from sugarcane straw was screened for its phenolic compounds content, and the potential use of this extract in the development of a food ingredient was further evaluated. Fifty different secondary metabolites belonging to the hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids were identified by liquid chromatography–electrospray ionization–ultrahigh-resolution—quadrupole time of flight–mass spectrometry (LC-ESI-UHR-QqTOF-MS). The predominant phenolic compounds found were 4-hydroxybenzaldehyde, chlorogenic acid, and 5-O-feruloylquinic acid. The obtained extracts showed strong potential as food preservatives by exhibiting (a) antioxidant activity using both 2.2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt radical cation (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods; and (b) antimicrobial capacity, with a minimum inhibitory concentration of 50 mg/mL for Staphylococcus aureus, 74% inhibition for Bacillus cereus, and 44% for Salmonella enterica; and (c) the capacity to inhibit a food browning enzyme, tyrosinase (28–73% for 1–8 mg/ mL). Moreover, the extracts showed antidiabetic potential by inhibiting the enzymes α-glucosidase (15–38% for 1.25–5.00 mg/mL) and dipeptidyl peptidase-IV (DPP-IV) (62–114% for 0.31–5.00 mg/mL). The extract (0.625 mg/mL) also exhibited the capacity to reduce proinflammatory mediators (i.e., interleukins 6 and 8, and tumor necrosis factor alpha) when Caco-2 cells were stimulated with interleukin 1 beta. Thus, sugarcane straw extract, which is rich in phenolic compounds, showed high potential to be used in the development of food-preservative ingredients owing to its antioxidant and antimicrobial potential, and to be explored as a food supplement in diabetes prevention and as coadjuvant to reduce intestinal inflammation by reducing proinflammatory mediators.info:eu-repo/semantics/publishedVersio
Immobilization of streptavidin on a plasmonic Au-TiO2 thin film towards an LSPR biosensing platform
Optical biosensors based on localized surface plasmon resonance (LSPR) are the future of label-free detection methods. This work reports the development of plasmonic thin films, containing Au nanoparticles dispersed in a TiO2 matrix, as platforms for LSPR biosensors. Post-deposition treatments were employed, namely annealing at 400 °C, to develop an LSPR band, and Ar plasma, to improve the sensitivity of the Au-TiO2 thin film. Streptavidin and biotin conjugated with horseradish peroxidase (HRP) were chosen as the model receptor–analyte, to prove the efficiency of the immobilization method and to demonstrate the potential of the LSPR-based biosensor. The Au-TiO2 thin films were activated with O2 plasma, to promote the streptavidin immobilization as a biorecognition element, by increasing the surface hydrophilicity (contact angle drop to 7°). The interaction between biotin and the immobilized streptavidin was confirmed by the detection of HRP activity (average absorbance 1.9 ± 0.6), following a protocol based on enzyme-linked immunosorbent assay (ELISA). Furthermore, an LSPR wavelength shift was detectable (0.8 ± 0.1 nm), resulting from a plasmonic thin-film platform with a refractive index sensitivity estimated to be 33 nm/RIU. The detection of the analyte using these two different methods proves that the functionalization protocol was successful and the Au-TiO2 thin films have the potential to be used as an LSPR platform for label-free biosensors.Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020, UIDB/04050/2020, and UID/EMS/00285/2020, and by the projects NANO4BIO: POCI-01-0145-FEDER-032299, with FCT reference PTDC/FIS-MAC/32299/2017, and CO2Plasmon, with FCT reference EXPL/CTM-REF/0750/2021. Patrícia Pereira-Silva, Diana I. Meira, and Diogo Costa acknowledge FCT for their Ph.D. scholarships, 2020.08235.BD, SFRH/BD/143262/2019, and SFRH/BD/136279/2018, respectively. Augusto Costa-Barbosa also acknowledges FCT for his Ph.D. scholarships SFRH/BD/133513/2017 and COVID/BD/152169/2021. The authors would like to express their gratitude to Nuno P. Barradas (C2TN, University of Lisbon) and Eduardo Alves (IPFN, University of Lisbon) for RBS measurements and analysis
Effects of different tooth bleaching systems on the roughness and superficial morphology of enamel and a restorative composite resin
Objetivo: Avaliar as alterações de rugosidade e morfologia superficial do esmalte e da resina composta após diferentes técnicas de clareamento dental. Material e método: incisivos bovinos íntegros foram selecionados, sendo que cavidades padronizadas foram confeccionadas na face vestibular, as quais foram restauradas com resina composta. Os dentes foram distribuídos em grupos, de acordo com o tratamento proposto: G1-clareamento com peróxido de carbamida (PC) 10%; G2 - clareamento com peróxido de hidrogênio (PH) a 38%; G3- clareamento com PH a 38% associado à foto-ativação com LED. Para G1, o agente clareador foi aplicado por 8 horas diárias durante 21 dias. Para\ud
G2 e G3, foram realizadas 3 sessões de clareamento, caracterizadas por 3 aplicações do gel clareador por 15 minutos, com intervalos de 7 dias entre as sessões, sendo que em G3 o gel clareador foi ativado com LED (470nm) por 6 minutos. As superfícies do esmalte e da resina composta foram avaliadas antes e após o procedimento clareador através de um rugosímetro e de um microscópio de força atômica. Resultados: Os resultados demonstraram diferença significante da rugosidade do esmalte antes e após o clareamento apenas para G1, em relação ao controle (Wilcoxon, p<0,05). Para a resina composta, nenhum dos grupos apresentou diferença estatística em relação ao controle (Mann-Whitney, p>0,05). Conclusão: O aumento da rugosidade do esmalte aconteceu apenas quando o clareamento foi realizado através da aplicação de um gel com 10% de PC. Nenhum dos procedimentos clareadores avaliados nesta pesquisa interferiram na rugosidade e morfologia da resina composta.CNPq (135181/2010-0; 30129/2010-1
Development and validation of a simple and rapid capillary zone electrophoresis method for determination of nnrti nevirapine in pharmaceutical formulations
A simple and fast capillary zone electrophoresis (CZE) method has been developed and validated for quantification of a non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine, in pharmaceuticals. The analysis was optimized using 10 mmol L-1 sodium phosphate buffer pH 2.5, +25 kV applied voltage, hydrodynamic injection 0.5 psi for 5 s and direct UV detection at 200 µm. Diazepam (50.0 µg mL-1) was used as internal standard. Under these conditions, nevirapine was analyzed in approximately less than 2.5 min. The analytical curve presented a coefficient of correlation of 0.9994. Limits of detection and quantification were 1.4 µg mL-1 and 4.3 µg mL-1, respectively. Intra- and inter-day precision expressed as relative standard deviations were 1.4% and 1.3%, respectively and the mean recovery was 100.81%. The active pharmaceutical ingredient was subjected to hydrolysis (acid, basic and neutral) and oxidative stress conditions. No interference of degradation products and tablet excipients were observed. This method showed to be rapid, simple, precise, accurate and economical for determination of nevirapine in pharmaceuticals and it is suitable for routine quality control analysis since CE offers benefits in terms of quicker method development and significantly reduced operating costs.Um método simples e rápido por eletroforese capilar foi desenvolvido e validado para a quantificação do inibidor não nucleosídeo da transcritase reversa (NNRTI) nevirapina, em medicamentos. A análise foi otimizada utilizando tampão fosfato de sódio 10 mmol L-1, pH 2,5, voltagem aplicada de +25 kV, injeção hidrodinâmica a 0,5 psi por 5 s e detecção UV em 200 µm. Diazepam (50,0 µg mL-1) foi usado como padrão interno. Sob estas condições, nevirapina foi analisada em aproximadamente menos de 2,5 min. A curva analítica apresentou um coeficiente de correlação de 0,9994. Os limites de detecção e quantificação foram 1,4 µg mL-1 e 4,3 µg mL-1, respectivamente. Precisões intra e inter-dia expressas como desvio padrão relativo foram 1,4% e 1,3%, respectivamente e a recuperação média foi de 100,81%. O fármaco foi submetido a testes de hidrólises (ácida, básica e neutra) e a estresse oxidativo. Não foi observada interferência por parte dos produtos de degradação, nem dos excipients na análise da nevirapina. Este método mostrou ser rápido, simples, preciso, exato e econômico para a determinação de nevirapina em produtos farmacêuticos e é apropriado para o controle de qualidade em análise de rotina uma vez que a eletroforese capilar oferece benefícios em termos de desenvolvimento rápido dos métodos e custos muito reduzidos de operação.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
Overview of phlorotannins’ constituents in Fucales
Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales.This work received financial support from PT national funds (FCT/MCTES, Fundação
para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through
the projects UIDB/50006/2020 and UIDP/50006/2020. Thanks to PTDC/BAA-AGR/31015/2017,
“Algaphlor—Brown algae phlorotannins: From bioavailability to the development of new functional
foods”, co-financed by the Operational Programme for Competitiveness and Internationalization—
POCI, within the European Regional Development Fund (FEDER), and the Science and Technology
Foundation (FCT), through national funds. Silva S. thanks FCT for funding through program DL
57/2016–Norma transitória (Ref. SFRH/BPD/74299/2010)
Chitosan/nanocellulose electrospun fibers with enhanced antibacterial and antifungal activity for wound dressing applications
The combination of biodegradable fibers at nanoscale with plant-based extracts is attracting increasing attention to produce wound dressing systems. In this work, nanofibers based on chitosan (CS), poly(ethylene oxide) (PEO), cellulose nanocrystals (CNC) and acacia plant-based extract were developed by electrospinning. Firstly, the polymeric formulations and electrospinning parameters were optimized, resulting in nanofibers with average diameters of 80 nm. CNC were successfully introduced into the optimized CS/PEO blend and the membranes were characterized by FESEM, ATR-FTIR, TGA, XRD, WVTR and WCA. The CNC incorporation improved the nanofibers' physical integrity, morphology, diameters, water vapor transmission rate and thermal properties. After acacia introduction into the best CS/PEO/CNC system, the antibacterial effect was relatively maintained while the antifungal activity was enhanced for some fungi, demonstrating its great effect against a wide range of microorganisms, which is crucial to prevent or treat infections. All the developed systems exhibited absence of cytotoxicity in non-tumor cells, suggesting their biocompatibility. Finally, a continuous release of the acacia extract was observed for 24 h, showing its prolonged action, which contributes to the healing process while reduces the frequency of dressing's replacement. Overall, the developed nanofibers are very promising to act as localized drug delivery systems for wound care applications.The authors are thankful to TSSiPRO project, operation code
NORTE01-0145-FEDER-000015. The authors are also grateful to FCT,
Portugal for financial support through national funds FCT/MCTES to
CIMO (UIDB/00690/2020) and to 2C2T (UID/CTM/00264/2019). D. P.
Ferreira thank the national funding by FCT through the individual scientific
employment program-contract (CEECIND/02803/2017), S. M.
Costa thank the FCT PhD Scholarship (SFRH/BD/147517/2019), and L.
Barros and R. Calhelha thank the institutional scientific employment program-contract. This work has been supported by the Ministry of
Education, Science and Technological Development of Republic of
Serbia (451-03-68/2020-14/200007).CEECIND/02803/2017SFRH/BD/147517/2019info:eu-repo/semantics/publishedVersio
Xanthene Derivatives Targeting Bacterial Efflux Pumps, Quorum-Sensing, and Biofilm Formation
The rise of multidrug resistance (MDR) bacteria in nosocomial and health-care institutions is widespread and is currently recognized as a major medical challenge. Mechanisms of bacterial resistance, namely, quorum sensing (QS), biofilm formation, and efflux pumps, have been identified as critical biological processes in MDR bacteria. Following previous reports on the activity of phenothiazines against mechanisms of bacterial resistance, in this work we focus on the synthesis of xanthene derivatives aiming to discover phenothiazine bioisosteres with improved activity. Four compounds were obtained from the conjugation of xanthydrol with sulfonamides and aniline and were fully characterized. Their antibacterial activity was assessed considering their minimum inhibitory concentration (MIC) against Gram-positive and Gram-negative strains, efflux pump inhibition, influence on biofilm formation and quorum-sensing (QS) inhibition. It was observed that the MIC of all the tested compounds was above 64 µg/mL The four 9-xanthenyl derivatives obtained, particularly the xanthene sulfonamide derivatives 3b and 3c, showed promising results on QS inhibition with a reduction of pigment production of 48 and 41 mm, and on biofilm formation with a reduction of 78 and 79%, respectively
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