68 research outputs found

    A Dual Measurement and Stimulating System to Monitor and Promote NNS

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    The present paper presents a dual system that can be used to measure and to generate non-nutritive sucking (NNS) signals. The NNS measurement is based on a pressure sensor that is pneumatically connected to a silicone pacifier. By its turn, the NNS stimulator is based on a miniature pump and a miniature electro-valve that are operated by opposite phased signals to produce the pulsed pressure signal that is pneumatically applied to the silicone pacifier. The paper highlights some specific issues related with the calibration of the pneumatic signal measuring chain. Processing and wireless transmission capabilities are provided by a low-cost solution based on a microcontroller. Calibration and experimental results are also included in the paper.info:eu-repo/semantics/publishedVersio

    Software Based Sigma-Delta Converter with Auto-Calibration Capabilities

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    Trabalho apresentado em 1st IFSA Frequency & Time Conference (IFTC’ 2019), setembro 2019, Tenerife, EspanhaThis paper presents a software based sigma-delta converter. The proposed A/D converter represents a lowcost and flexible digitalization solution that can be used in a large number of applications. The proposed discrete A/D converter tasks, that are performed by a microcontroller, include: digital filtering, oversampling, noise shaping and decimation. A simple implementation of the digital filtering is easily implemented by counting the number of high and low pulses contained in the feedback bit stream generated by the microcontroller. The first part of the paper contains an overview of the main characteristics of sigma-delta converters, the second part includes a brief description of the proposed sigma-delta converter, hardware, software and implementation details, and the last part will include simulation and experimental results.N/

    The effect of nanotube surface oxidation in the electrical response of MWCNT/PVDF nanocomposites

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    Carbon nanotubes / poly(vinylidene fluoride) composites were prepared using CNT with different oxidation and thermal treatments. The oxidation procedure leads to CNT with the most acidic characteristics that lower the degree of crystallinity of the polymer and contribute to a large increase of the dielectric constant. The surface treatments, in general, increase percolation threshold and decrease conductivity, but, on the other hand, are able to promote the nucleation of the electroactive phase of the polymer, which is suitable for the use of PVDF in sensors, actuators and other smart materials applications. Finally, the surface treatments do not seem to affect CNT interaction among them, reaching similar degrees of dispersion in all cases, as shown by the SEM results. The maximum value of the dielectric constant is ~630. It is demonstrated that the composite conductivity can be attributed to a hopping mechanism that is strongly affected by the surface treatment of the CNT.The authors thank the Fundacao para a Ciencia e a Tecnologia (FCT), Portugal, for financial support through the projects PTDC/CTM/69316/2006 and NANO/NMed-SD/0156/2007), and CIENCIA 2007 program for S.A.C.; V. S., J.S. and J.N.P. also thank FCT for the SFRH/BPD/63148/2009, SFRH/BD/60623/2009 and SFRH/BD/66930/2009 grants

    Assessment of solar driven TiO2-assisted photocatalysis efficiency on amoxicillin degradation

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    The objective of this work was to evaluate the efficiency of a solar TiO2-assisted photocatalytic process on amoxicillin (AMX) degradation, an antibiotic widely used in human and veterinary medicine. Firstly, solar photolysis of AMX was compared with solar photocatalysis in a compound parabolic collectors pilot scale photoreactor to assess the amount of accumulated UV energy in the system (Q (UV)) necessary to remove 20 mg L-1 AMX from aqueous solution and mineralize the intermediary by-products. Another experiment was also carried out to accurately follow the antibacterial activity against Escherichia coli DSM 1103 and Staphylococcus aureus DSM 1104 and mineralization of AMX by tracing the contents of dissolved organic carbon (DOC), low molecular weight carboxylate anions, and inorganic anions. Finally, the influence of individual inorganic ions on AMX photocatalytic degradation efficiency and the involvement of some reactive oxygen species were also assessed. Photolysis was shown to be completely ineffective, while only 3.1 kJ(UV) L-1 was sufficient to fully degrade 20 mg L-1 AMX and remove 61 % of initial DOC content in the presence of the photocatalyst and sunlight. In the experiment with an initial AMX concentration of 40 mg L-1, antibacterial activity of the solution was considerably reduced after elimination of AMX to levels below the respective detection limit. After 11.7 kJ(UV) L-1, DOC decreased by 71 %; 30 % of the AMX nitrogen was converted into ammonium and all sulfur compounds were converted into sulfate. A large percentage of the remaining DOC was in the form of low molecular weight carboxylic acids. Presence of phosphate ions promoted the removal of AMX from solution, while no sizeable effects on the kinetics were found for other inorganic ions. Although the AMX degradation was mainly attributed to hydroxyl radicals, singlet oxygen also plays an important role in AMX self-photosensitization under UV/visible solar light

    Incidence of postoperative residual neuromuscular blockade: a multicenter, observational study in Portugal (INSPIRE 2)

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    Background: Although the use of neuromuscular blocking agents (NMBAs) optimizes surgical conditions and facilitates tracheal intubation, it can lead to residual neuromuscular blockade (RNMB), with postoperative complications. This study aimed to assess RNMB incidence and management in Portugal. Methods: Prospective observational study of patients admitted for elective surgery requiring general anesthesia with nondepolarizing NMBAs between July 2018 and July 2019 at 10 Portuguese hospitals. The primary endpoint was the proportion of patients arriving at postanesthesia care unit (PACU) with a TOF ratio ,0.9. Results: A total of 366 patients were included, with a median age of 59 years, and 89.1% classified as ASA II or III. Rocuronium was the most used NMBA (99.5%). A total of 96.2% of patients received a reversal agent, 96.6% of which sugammadex and 3.4% neostigmine. Twenty patients displayed a TOF ratio ,0.9 at PACU arrival, representing an RNMB incidence of 5.5% (95% CI, 3.1%–7.8%). Only two patients displayed a TOF ratio ,0.7. RNMB incidence was 16.7% with neostigmine and 5.3% with sugammadex (P 5 .114). In patients with intraoperative neuromuscular blockade (NMB) monitoring, RNMB incidence was 5% (95% CI, 2%–8%), which varied significantly according to the type of monitoring (P 5 .018). Incidence of adverse events was 3.3% (2 severe and 10 moderate). Conclusions: The reported overall incidence of 5.5% is numerically lower than results from similar observational studies. An appropriate pharmacological neuromuscular reversal strategy, guided by quantitative neuromuscular monitoring, has the potential to achieve even better results, converting RNMB from an unusual to a very rare or even inexistent event.info:eu-repo/semantics/publishedVersio

    Effect of surface biotreatments on construction materials

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    STSM Grant from the COST Action CA15202. Spanish Ministry of Economy - project BIA2017-83526-R. project DB-Heritage – Database of building materials with historical and heritage interest (PTDC/EPH-PAT/4684/2014). IF/01054/2014/CP1224/CT0005. FCT/MCTES (UID/QUI/50006/2019; UID/Multi/04378/2019). POCI-01-0145-FEDER-007728. Nídia Almeida is supported by the Radiation Biology and Biophysics Doctoral Training Programme (RaBBiT-PD/00193/2012; UCIBIO-UID/Multi/04378/2019 and by a PhD fellowship from FCT/MCTES (PD/BD/106034/2015).Surface treatment technology is instrumental to construction material conservation and more specifically to preventing decay and improving durability. Surface treatments help protect and consolidate the built heritage against material damage, reducing repair and replacement costs. This study assessed the effect of two eco-friendly healing agents, one generated by iron-enriched Escherichia coli and the other by mixed microbial cultures that metabolise glycerol, a biodiesel processing by-product, to produce polyhydroxyalkanoates. Healing was monitored by measuring the water drop absorption rate in cement mortar, air lime mortar, ceramic brick, limestone, adobe and compressed earth block. The agents tested lengthened water absorption times in all the materials studied, confirming their efficacy as external repair treatments for construction materials.authorsversionpublishe

    Process enhancement at near neutral pH of a homogeneous photo-Fenton reaction using ferricarboxylate complexes: Application to oxytetracycline degradation

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    This work demonstrates the application at near neutral pH of a photo-Fenton reaction mediated by ferricarboxylates on the treatment of aqueous solutions containing the antibiotic Oxytetracycline (OTC) under solar irradiation. The formation of a Fe:OTC complex after Fe2+ oxidation to Fe3+, in the presence of H2O2, showed the inconvenience of using the conventional Fe2+/H2O2/UV-Vis process at near neutral pH levels, as the complex is retained in the filter. To overcome this, a Fe3+/Oxalate/UV-Vis or Fe3+/Citrate/H2O2/UV-Vis process was proposed. The higher tendency of Fe3+ to form complexes with carboxylates avoids the formation of Fe:OTC complexes and allows for proper OTC detection along reaction times. The photo-Fenton process itself is improved by the extension of the iron solubility to higher and more practical pH values, by the increase of the quantum yield of Fe2+ production and by presenting stronger radiation absorption at wavelengths up to 580 nm. In this way, process efficiency was evaluated for different variables such as Fe3+ concentration, pH, temperature and irradiance, using a compound parabolic collector (CPC) photoreactor at lab-scale under simulated solar radiation. Reaction rates were compared in the presence of different inorganic anions and humic acids, and in two different real wastewater matrixes. Results obtained in a CPC pilot-scale plant under natural solar light, using an iron/oxalate molar rati

    Genetically engineered Silk-Elastin-Like Proteins as a versatile platform for the development of new biomaterials

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    [Excerpt] Throughout evolution nature created and refined proteins for a wide range of functions, working as structural components or as molecular motors. In this sense, the natural fibrous proteins represent the utmost case of function specialization and high performance materials. The remarkable mechanical properties of proteins like elastin or silk are founded on conservative blocks of amino acid sequences that propagate through the natural protein. These repetitive amino acid sequences are arranged in a way that creates flexible, rigid or tough domains, which are responsible for the physical and mechanical properties of the natural protein. Indeed, the recognition of the mechanics linking the nano- and micro-scale structure with the macromolecular assembly and organization, enabled molecular biologists to understand nature’s refined ways of creating high performance structural materials. Advances in synthetic protein biotechnology, emerging from the increase of knowledge in structural and molecular biology, combined with the use of recombinant DNA technology and biotechnology processes, made possible the advent of a new class of artificial biomacromolecules, the recombinant Protein-Based Polymers (rPBPs). This new class of protein-based materials, inspired in nature and with precisely controlled amino acid sequences, mimic the properties of their natural counterparts but can also combine in the same polypeptide chain the properties of two or more different proteins, creating copolymers with distinct properties from their native equivalents. Indeed, by recombinant DNA technology, it is possible to design and produce tailored synthetic genes, allowing for the creation of multifunctional complex PBPs with absolute control of its composition, structure and molecular weight. [...]This work is supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) and by the project EcoAgriFood (NORTE-01-0145-FEDER-000009), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). It is also supported by FCT within the ERA-NET IB, project FunBioPlas with grant number ERA-IB-15-089 and FCT reference ERA-IB-2-6/0004/2014. AMPereira acknowledges DP_AEM and FCT for the PD/BD/113811/2015 grant

    Errors in protein synthesis increase the level of saturated fatty acids and affect the overall lipid profiles of yeast

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    The occurrence of protein synthesis errors (mistranslation) above the typical mean mistranslation level of 10-4 is mostly deleterious to yeast, zebrafish and mammal cells. Previous yeast studies have shown that mistranslation affects fitness and deregulates genes related to lipid metabolism, but there is no experimental proof that such errors alter yeast lipid profiles. We engineered yeast strains to misincorporate serine at alanine and glycine sites on a global scale and evaluated the putative effects on the lipidome. Lipids from whole cells were extracted and analysed by thin layer chromatography (TLC), liquid chromatography-mass spectrometry(LC-MS) and gas chromatography (GC). Oxidative damage, fatty acid desaturation and membrane fluidity changes were screened to identify putative alterations in lipid profiles in both logarithmic (fermentative) and post-diauxic shift (respiratory) phases. There were alterations in several lipid classes, namely lyso-phosphatidylcholine, phosphatidic acid, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and triglyceride, and in the fatty acid profiles, namely C16:1, C16:0, C18:1 and C18:0. Overall, the relative content of lipid species with saturated FA increased in detriment of those with unsaturated fatty acids. The expression of the OLE1 mRNA was deregulated, but phospholipid fluidity changes were not observed. These data expand current knowledge of mistranslation biology and highlight its putative roles in human diseases.publishe

    Magnetoliposomes containing calcium ferrite nanoparticles for applications in breast cancer therapy

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    Magnetoliposomes containing calcium ferrite (CaFe2O4) nanoparticles were developed and characterized for the first time. CaFe2O4 nanoparticles were covered by a lipid bilayer or entrapped in liposomes forming, respectively, solid or aqueous magnetoliposomes as nanocarriers for new antitumor drugs. The magnetic nanoparticles were characterized by UV/Visible absorption, XRD, HR-TEM, and SQUID, exhibiting sizes of 5.2 ± 1.2 nm (from TEM) and a superparamagnetic behavior. The magnetoliposomes were characterized by DLS and TEM. The incorporation of two new potential antitumor drugs (thienopyridine derivatives) specifically active against breast cancer in these nanosystems was investigated by fluorescence emission and anisotropy. Aqueous magnetoliposomes, with hydrodynamic diameters around 130 nm, and solid magnetoliposomes with sizes of ca. 170 nm, interact with biomembranes by fusion and are able to transport the antitumor drugs with generally high encapsulation efficiencies (70%). These fully biocompatible drug-loaded magnetoliposomes can be promising as therapeutic agents in future applications of combined breast cancer therapy.This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2013; UID/FIS/04650/2019), CQUM (UID/QUI/00686/2016; UID/QUI/00686/2019) and LA-26 (PEst-C/SAU/LA0026/2013), and through the research project PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020), financed by FCT, European Fund of Regional Development (FEDER), COMPETE2020 and Portugal2020. The magnetic measurements were supported by projects UTAP-EXPL/NTec/0046/2017, NORTE-01-0145-FEDER-028538 e PTDC/FIS-MAC/29454/2017. The APC was also funded by FCT. B.D.C. acknowledges FCT for a PhD grant (SFRH/BD/141936/2018)
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