Comparison of surface topography in machining Ti alloys for biomedical applications: correlative microscopy approach for qualitative and quantitative analysis

In the last decades, the demand for biocompatible materials has increased because they are widely selected to manufacture medical devices such as dental and surgical implants. The improvement of these materials used to fabricate biocomponents is a constant objective in research focused on reducing negative impacts on patients. Currently, the most commonly used metal alloy in the biomedical industry is Ti-6Al-4V. Although it has interesting properties, this material may present a risk to the patient due to the presence of vanadium. Alternatively, the Ti-6Al-7Nb alloy may be a candidate to replace traditional alloys, however more studies are required for understanding the machining techniques of biomedical components. The study of surface topography, through modern microscopy techniques, presents great potential to optimize the machining process of this material. The objective of this work was to propose a correlative microscopy technique for a comparative analysis of surfaces machined by the turning process of the Ti-6Al-4V and Ti-6Al-7Nb alloys. This technique was based on the association of the extended field-depth method from Optical Microscopy (OM) with Scanning Electron Microscopy (SEM) and microanalysis modes.publishe

Crenças sobre violência conjugal em contexto rural e urbano

Poster apresentado no III Simpósio Olhares da Psicologia. 5 de Maio de 2016, Egas Moniz, Monte de Caparica, PortugalN/

Removal of polycyclic aromatic hydrocarbons in water, using byproducts of cork industry

Os Hidrocarbonetos Aromáticos Policíclicos (HAPs) são contaminantes persistentes em meio aquoso. Estes compostos são conhecidos pelas suas propriedades carcinogénicas, mutagénicas e genotóxicas. O principal objetivo deste trabalho consistiu na avaliação das potencialidades de subprodutos da indústria corticeira, como adsorventes alternativos para a remoção de cinco HAPs em meio aquoso: benzo(a)pireno, benzo(ghi)perileno, benzo(b)fluoranteno, benzo(k)fluoranteno e indeno(1,2,3-cd)pireno. A metodologia analítica para quantificar os HAPs envolveu a preparação das amostras, através da técnica de extração em fase sólida (SPE), e a quantificação dos compostos analisados por cromatografia líquida com detetor de fluorescência (LC-FLD). O método foi otimizado e validado, obtendo-se limites de quantificação de 0,004 μg/L para todos os HAPs. Os estudos incidiram na utilização de uma amostra de cortiça, pó de aglomerado de cortiça expandida (PACE), obtida por aglutinação de cortiça em condições hidrotérmicas, a qual nos estudos preliminares revelou desempenho semelhante aos carvões ativados. Com exceção do benzo(ghi)perileno, os resultados mostram que o processo de adsorção dos HAPs na amostra PACE segue uma cinética de pseudo-segunda ordem e as isotérmicas ajustam-se ao modelo de Langmuir.Polycyclic Aromatic Hydrocarbons (PAHs) are persistent contaminants present in aqueous media. These compounds are known for their carcinogenic, mutagenic and genotoxic properties. The main objective of this work was to evaluate the potential of cork industry by-products as alternative adsorbents for the removal of five PAHs in aqueous media: benzo(a)pyrene, benzo(ghi)perylene, benzo(b)fluoranthene, benzo(k)fluoranthene e indeno( 1,2,3-cd)pyrene. The analytical methodology used to quantify PAHs consisted in the first step of sample preparation using solid phase extraction (SPE) technique, followed by quantification by liquid chromatography with a fluorescence detector (LC-FLD). The method was optimized and validated, yielding limits of quantification of 0.004 μg L-1 for all PAHs. The studies have focused on the use of a sample cork (PACE), obtained by agglutination of cork under hydrothermal conditions, which in preliminary studies attained removal efficiencies similar to those of activated carbons. With the exception of benzo(ghi)perylene, the results reveal that adsorption process of PAHs on sample PACE obey to the pseudo-second order kinetic equation and to the Langmuir model.Este trabalho foi suportado financeiramente pelo programa QREN-COMPETE, através do projeto de investigação Watercork (nº 2009/5523)

Potassium Ferrite for Biomedical Applications

LA/P/0037/2020. LA/P/0006/2020. Publisher Copyright: © 2023 by the authors.Ferrites have been widely studied for their use in the biomedical area, mostly due to their magnetic properties, which gives them the potential to be used in diagnostics, drug delivery, and in treatment with magnetic hyperthermia, for example. In this work, KFeO2 particles were synthesized with a proteic sol-gel method using powdered coconut water as a precursor; this method is based on the principles of green chemistry. To improve its properties, the base powder obtained was subjected to multiple heat treatments at temperatures between 350 and 1300 °C. The samples obtained underwent structural, morphological, biocompatibility, and magnetic characterization. The results show that upon raising the heat treatment temperature, not only is the wanted phase detected, but also the secondary phases. To overcome these secondary phases, several different heat treatments were carried out. Using scanning electron microscopy, grains in the micrometric range were observed. Saturation magnetizations between 15.5 and 24.1 emu/g were observed for the samples containing KFeO2 with an applied field of 50 kOe at 300 K. From cellular compatibility (cytotoxicity) assays, for concentrations up to 5 mg/mL, only the samples treated at 350 °C were cytotoxic. However, the samples containing KFeO2, while being biocompatible, had low specific absorption rates (1.55–5.76 W/g).publishersversionpublishe

Peptide-induced permeation of model membranes by antimicrobial peptidomimetics

In the present communication, a set of Peptaibolin and several peptidomimetics incorporating unnatural α,α-dialkylglycines (Deg, Dpg, Ac6c) were studied for their ability to interact and permeate model membranes from phosphatidylcholine/cholesterol, in different ratios. The permeation activity was monitored by fluorescence spectroscopy, following the release of encapsulated 6-carboxyfluorescein.Fundação para a Ciência e a Tecnologia (Portugal) and FEDER-COMPETE-QREN-EU for financial support through projects PTDC/QUI-BIQ/118389/2010 (FCOMP-01-0124-FEDER-020906), PEst-C/QUI/UI0686/2013 (F-COMP-01-0124-FEDER-037302), and PEst-C/FIS/UI0607/2013 (F-COMP-01-0124-FEDER-022711)

Permeation of model membranes by Peptaibolin mimetics bearing different α,α-dialkylglycines

Comunicação oral OC19 no XV EPI- Iberian Peptide Meeting, Porto, Portugal, 10-12 Fevereiro 2016.It is reported the membrane permeation studies of a model peptide, Peptaibolin (Ac-Leu-Aib-Leu-Aib-Phol), which is the shortest member of the peptaibols family, and several mimetics incorporating unnatural α,α- dialkylglycines (Deg, Dpg, Ac6c) at the native Aib positions. The model membranes were based on small unilamellar vesicles composed of phosphatidylcholines (egg lecithin, DPPC), phosphatidylglycerols (DPPG, DOPG) and cholesterol, at different compositions and ratios, containing a fluorescent probe encapsulated in their aqueous interior, in order to monitor the permeation process by fluorescence spectroscopy. The obtained results revealed a correlation between the length and bulk of the side chain of the unnatural α,α-dialkylglycines and the ability of the corresponding peptide to permeate the model membranes.The authors acknowledge Fundação para a Ciência e a Tecnologia (Portugal) and FEDER-COMPETE-QREN-EU for financial support through projects PTDC/QUIBIQ/118389/2010 (FCOMP-01-0124-FEDER-020906), PEst-C/QUI/UI0686/2013 (F-COMP-01- 0124-FEDER-037302), and PEst-C/FIS/UI0607/2013 (F-COMP-01-0124-FEDER-022711).info:eu-repo/semantics/publishedVersio

Membrane active peptides with unnatural amino acids: permeation studies in model membranes

Comunicação em painel P60 no 2nd Symposium on Medicinal Chemistry, Braga, Portugal, 8 Maio 2015It is reported the membrane permeation studies of Peptaibolin and several mimetics incorporating unnatural α,α-dialkylglycines (Deg, Dpg, Ac6c) with model membranes (egg phosphatidylcholine/cholesterol, in different ratios). The permeation activity was monitored by fluorescence spectroscopy, following release of an encapsulated fluorescent probe (6-carboxyfluorescein). The obtained results revealed a correlation between the length and bulk of the side chain of the unnatural α,α-dialkylglycines and the ability of the corresponding peptide to permeate the model membranes.Fundação para a Ciência e Tecnologia(Portugal) and FEDER-COMPETE for financial support through project PTDC/QUI-BIQ/118389/2010 (FCOMP- 01-0124-FEDER-020906) and PEst-C/QUI/UI0686/2013 (F-COMP-01-0124-FEDER-037302). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased with fund s from FCT and FEDERinfo:eu-repo/semantics/publishedVersio

Design and Optimization of Microbial Fuel Cells and Evaluation of a New Air-Breathing Cathode Based on Carbon Felt Modified with a Hydrogel—Ion Jelly®

Funding Information: This research was funded by Fundação para a Ciência e a Tecnologia projects DSAIPA/DS/0117/2020, UIDB/04565/2020, and UIDP/04565/2020, by the Associate Laboratory Institute for Health and Bioeconomy—i4HB project LA/P/0140/2020. This work was supported by the Associate Laboratory for Green Chemistry—LAQV financed by national funds from FCT/MCTES (UIDB/50006/2020). We also thank Fundação para a Ciência e Tecnologia (FCT) for funding (SFRH/BD/77568/2011 (R.N.L.C.); SFRH/BPD/80293/2011 (R.M.A.)). C.M.C. acknowledges FCT for the Ciência 2008 Program; S.V.R. acknowledges the financial support from FCT (Portuguese Foundation for Science and Technology) for a postdoctoral research grant (FRH/BPD/33864/2009). This work was supported by the Associate Laboratory for Green Chemistry—LAQV, financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020); the Institute for Bioengineering and Biosciences—iBB, financed by FCT (UID/BIO/04565/2013); and from Programa Operacional Regional de Lisboa 2020 (Project N. 007317). Publisher Copyright: © 2023 by the authors.The increased demand for alternative sustainable energy sources has boosted research in the field of fuel cells (FC). Among these, microbial fuel cells (MFC), based on microbial anodes and different types of cathodes, have been the subject of renewed interest due to their ability to simultaneously perform wastewater treatment and bioelectricity generation. Several different MFCs have been proposed in this work using different conditions and configurations, namely cathode materials, membranes, external resistances, and microbial composition, among other factors. This work reports the design and optimization of MFC performance and evaluates a hydrogel (Ion Jelly®) modified air-breathing cathode, with and without an immobilized laccase enzyme. This MFC configuration was also compared with other MFC configuration performances, namely abiotic and biocathodes, concerning wastewater treatment and electricity generation. Similar efficiencies in COD reduction, voltage (375 mV), PD (48 mW/m2), CD (130 mA/m2), and OCP (534 mV) were obtained. The results point out the important role of Ion Jelly® in improving the MFC air-breathing cathode performance as it has the advantage that its electroconductivity properties can be designed before modifying the cathode electrodes. The biofilm on MFC anodic electrodes presented a lower microbial diversity than the wastewater treatment effluent used as inocula, and inclusively Geobacteracea was also identified due to the high microbial selective niches constituted by MFC systems.publishersversionpublishe

3D digital breast cancer models with multimodal fusion algorithms

Breast cancer image fusion consists of registering and visualizing different sets of a patient synchronized torso and radiological images into a 3D model. Breast spatial interpretation and visualization by the treating physician can be augmented with a patient-specific digital breast model that integrates radiological images. But the absence of a ground truth for a good correlation between surface and radiological information has impaired the development of potential clinical applications. A new image acquisition protocol was designed to acquire breast Magnetic Resonance Imaging (MRI) and 3D surface scan data with surface markers on the patient's breasts and torso. A patient-specific digital breast model integrating the real breast torso and the tumor location was created and validated with a MRI/3D surface scan fusion algorithm in 16 breast cancer patients. This protocol was used to quantify breast shape differences between different modalities, and to measure the target registration error of several variants of the MRI/3D scan fusion algorithm. The fusion of single breasts without the biomechanical model of pose transformation had acceptable registration errors and accurate tumor locations. The performance of the fusion algorithm was not affected by breast volume. Further research and virtual clinical interfaces could lead to fast integration of this fusion technology into clinical practice.publishersversionpublishe

Unfolding kinetics of beta-lactoglobulin induced by surfactant and denaturant: a stopped-flow/fluorescence study

The beta ->alpha transition of beta-lactoglobulin, a globular protein abundant in the milk of several mammals, is investigated in this work. This transition, induced by the cationic surfactant dodecyltrimethylammonium chloride (DTAC), is accompanied by partial unfolding of the protein. In this work, unfolding of bovine beta-lactoglobulin in DTAC is compared with its unfolding induced by the chemical denaturant guanidine hydrochloride (GnHCl). The final protein states attained in the two media have quite different secondary structure: in DTAC the alpha-helical content increases, leading to the so-called alpha-state; in GnHCl the amount of ordered secondary-structure decreases, resulting in a random coil-rich final state (denatured, or D, state). To obtain information on both mechanistic routes, in DTAC and GnHCl, and to characterize intermediates, the kinetics of unfolding were investigated in the two media. Equilibrium and kinetic data show the partial accumulation of an on-pathway intermediate in each unfolding route: in DTAC, an intermediate (I-1) with mostly native secondary structure but loose tertiary structure appears between the native (beta) and alpha-states; in GnHCl, another intermediate (I-2) appears between states beta and D. Kinetic rate constants follow a linear Chevron-plot representation in GnHCl, but show a more complex mechanism in DTAC, which acts like a stronger binding species.info:eu-repo/semantics/publishedVersio