224 research outputs found

    Backside-surface imprinting as a new strategy to generate specific plastic antibody materials

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    A backside protein-surface imprinting process is presented herein as a novel way to generate specific synthetic antibody materials. The template is covalently bonded to a carboxylated-PVC supporting film previously cast on gold, let to interact with charged monomers and surrounded next by another thick polymer. This polymer is then covalently attached to a transducing element and the backside of this structure (supporting film plus template) is removed as a regular “tape”. The new sensing layer is exposed after the full template removal, showing a high density of re-binding positions, as evidenced by SEM. To ensure that the templates have been efficiently removed, this re-binding layer was cleaned further with a proteolytic enzyme and solution washout. The final material was named MAPS, as in the back-side reading of SPAM, because it acts as a back-side imprinting of this recent approach. It was able to generate, for the first time, a specific response to a complex biomolecule from a synthetic material. Non-imprinted materials (NIMs) were also produced as blank and were used as a control of the imprinting process. All chemical modifications were followed by electrochemical techniques. This was done on a supporting film and transducing element of both MAPS and NIM. Only the MAPS-based device responded to oxLDL and the sensing layer was insensitive to other serum proteins, such as myoglobin and haemoglobin. Linear behaviour between log(C, μg mL−1) versus charged tranfer resistance (RCT, Ω) was observed by electrochemical impedance spectroscopy (EIS). Calibrations made in Fetal Calf Serum (FCS) were linear from 2.5 to 12.5 μg mL−1 (RCT = 946.12 × log C + 1590.7) with an R-squared of 0.9966. Overall, these were promising results towards the design of materials acting close to the natural antibodies and applied to practical use of clinical interest

    Employing bacteria machinery for antibiotic detection: using DNA gyrase for ciprofloxacin detection

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    This work describes a new successful approach for designing biosensors that detect antibiotics. It makes use of a biomimetic strategy, by employing the biochemical target of a given antibiotic as its biorecognition element. This principle was tested herein for quinolones, which target DNA gyrase in bacteria. Ciprofloxacin (CIPRO) was tested as a representative antibiotic from the quinolone group; the sensitivity of biosensor to this group was confirmed by checking the response to another quinolone antibiotic (norfloxacin, NOR) and to a non-quinolone antibiotic (ampicillin, AMP). The biorecognition element used was DNA gyrase attached by ionic interactions to a carbon support, on a working electrode on common screen-printed electrodes (SPEs). The response against antibiotics was tested for increasing concentrations of CIPRO, NOR or AMP, and following the subsequent electrical changes by electrochemical impedance spectroscopy. The DNAgyrase biosensor showed sensitive responses for CIPRO and NOR, for concentrations down to 3.02nM and 30.2nM, respectively, with a very wide response range for CRIPRO, up to 30.2µM. Its response was also confirmed selective for quinolones, when compared to its response against AMP. Further comparison to an immunosensor of similar design (adding antibodies instead of DNA gyrase) was made, revealing favourable features for the new biomimetic biosensor with 1.52nM of limit of detection (LOD). Overall, the new approach presented herein is simple and effective for antibiotic detection, displaying a selective response against a given antibiotic group. The use of bacterial machinery as biorecognition element in biosensors may also provide a valuable tool to study the mechanism of action in bacterial cells of new drugs. This is especially important in the development of new drugs to fight bacterial resistance.The authors acknowledge funding from project PTDC/AAG-TEC/5400/2014 funded by European funds, through FEDER (European Funding or Regional Development) via COMPETE2020 – POCI (operational program for internationalization and competitively) and by national funding through the National Foundation for Science and Technology, I.P. (FCT). ARC also acknowledge funding to National Foundation for Science and Technology, I.P., through the PhD Grant, SFRH/BD/130107/2017.info:eu-repo/semantics/publishedVersio

    Specific label-free and real-time detection of oxidized low density lipoprotein (oxLDL) using an immunosensor with three monoclonal antibodies

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    Increased levels of plasma oxLDL, which is the oxidized fraction of Low Density Lipoprotein (LDL), are associated with atherosclerosis, an inflammatory disease, and the subsequent development of severe cardiovascular diseases that are today a major cause of death in modern countries. It is therefore important to find a reliable and fast assay to determine oxLDL in serum. A new immunosensor employing three monoclonal antibodies (mAbs) against oxLDL is proposed in this work as a quick and effective way to monitor oxLDL. The oxLDL was first employed to produce anti-oxLDL monoclonal antibodies by hybridoma cells that were previously obtained. The immunosensor was set-up by selfassembling cysteamine (Cyst) on a gold (Au) layer (4 mm diameter) of a disposable screen-printed electrode. Three mAbs were allowed to react with N-hydroxysuccinimide (NHS) and ethyl(dimethylaminopropyl)carbodiimide (EDAC), and subsequently incubated in the Au/Cys. Albumin from bovine serum (BSA) was immobilized further to ensure that other molecules apart from oxLDL could not bind to the electrode surface. All steps were followed by various characterization techniques such as electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV). The analytical operation of the immunosensor was obtained by incubating the sensing layer of the device in oxLDL for 15 minutes, prior to EIS and SWV. This was done by using standard oxLDL solutions prepared in foetal calf serum, in order to simulate patient's plasma with circulating oxLDL. A sensitive response was observed from 0.5 to 18.0 mg mL 1 . The device was successfully applied to determine the oxLDL fraction in real serum, without prior dilution or necessary chemical treatment. The use of multiple monoclonal antibodies on a biosensing platform seemed to be a successful approach to produce a specific response towards a complex multi-analyte target, correlating well with the level of oxLDL within atherosclerosis disease, in a simple, fast and cheap way

    O desafio da educação contínua no contexto das organizações universitárias

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    Ao ritmo do desenvolvimento tecnológico actual, as pessoas são frequentemente colocadas em situação de desajustamento de competências. Neste contexto, a educação contínua (EC) parece constituir a resposta mais apropriada à crescente procura de novos saberes. Pelo conjunto de conhecimentos e competências que detêm, as universidades têm sido apontadas como prestadoras privilegiadas de serviços de EC. Acrescente-se que a tendência de diminuição do número de jovens que acede ao ensino universitário pressiona as universidades a captar novos públicos, compelindo-as a oferecer serviços de EC atractivos e de qualidade. Este documento pretende ser um contributo para a análise das questões associadas à educação contínua universitária, salientando, por um lado, a necessidade de responder a um mercado pragmático e exigente e, por outro, os constrangimentos associados à dinâmica organizacional das universidades. Tendo por base parte dos resultados de dois estudos efectuados na Universidade do Porto em 2000, confrontam-se duas visões complementares da EC: a perspectiva do interior da universidade, no que se refere aos aspectos associados às boas práticas e às dificuldades; e a perspectiva das empresas, quanto à capacidade das universidades para prestarem este tipo de serviços. Como conclusão, apontam-se alguns caminhos que podem contribuir para que as universidades respondam convenientemente a este desafio

    Production of ornamental sunflower irrigated with oilfield produced water in the Brazilian semiarid region.

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    Made available in DSpace on 2018-01-16T23:26:57Z (GMT). No. of bitstreams: 1 ART17084.pdf: 389793 bytes, checksum: 253548ece00ce108f5f4a9dc43f526d0 (MD5) Previous issue date: 2018-01-16bitstream/item/171210/1/ART17084.pd

    Tooth avulsion accidents due to urgent and emergency orotracheal intubation

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    Intubation is necessary during critical situations to reduce the risk of death. In Brazil, a need exists to determine the prevalence of tooth avulsions in emergency and urgent care. The objective of this study was to identify the causes of orotracheal intubation (OTI), the number of tooth avulsions, and the avulsed teeth that result from urgent and emergency intubation. The sample consisted of 116 patients (total group) in intensive care units (ICUs) distributed across Group 1 (G1), which was composed of 71 patients from an urgent-care hospital, and Group 2 (G2), which was composed of 45 patients from an emergency hospital. Clinical examinations showed dental alveolus with signs of recent exodontia in the upper and lower anterior regions. Sociodemographic data and the reason for intubation were evaluated. The Shapiro-Wilk normality test, chi-square test, Fisher?s exact test, Mann-Whitney U test, and univariate logistic regression were performed with a significance level of 5%. The avulsion prevalence was 4.3%, with more cases receiving emergency intubation (n=4). All avulsions occurred in adults, and a significant difference (p=0.011) was observed with regard to the elderly. A 1-year reduction in age increased the chance of tooth avulsion during intubation by 1.09 times; being female increased the chance by 2.88 times. Pulmonary problems were the major causes of intubation, with the highest tooth avulsion prevalence observed during emergency intubation. The avulsed teeth were 11, 12, 13, 22, 32, and 33 across all cases
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