68 research outputs found

    Activity of daptomycin- and vancomycin-loaded poly-epsilon-caprolactone microparticles against mature staphylococcal biofilms.

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    The aim of the present study was to develop novel daptomycin-loaded poly-epsilon-caprolactone (PCL) microparticles with enhanced antibiofilm activity against mature biofilms of clinically relevant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and polysaccharide intercellular adhesin-positive Staphylococcus epidermidis. Daptomycin was encapsulated into PCL microparticles by a double emulsion-solvent evaporation method. For comparison purposes, formulations containing vancomycin were also prepared. Particle morphology, size distribution, encapsulation efficiency, surface charge, thermal behavior, and in vitro release were assessed. All formulations exhibited a spherical morphology, micrometer size, and negative surface charge. From a very early time stage, the released concentrations of daptomycin and vancomycin were higher than the minimal inhibitory concentration and continued so up to 72 hours. Daptomycin presented a sustained release profile with increasing concentrations of the drug being released up to 72 hours, whereas the release of vancomycin stabilized at 24 hours. The antibacterial activity of the microparticles was assessed by isothermal microcalorimetry against planktonic and sessile MRSA and S. epidermidis. Regarding planktonic bacteria, daptomycin-loaded PCL microparticles presented the highest antibacterial activity against both strains. Isothermal microcalorimetry also revealed that lower concentrations of daptomycin-loaded microparticles were required to completely inhibit the recovery of mature MRSA and S. epidermidis biofilms. Further characterization of the effect of daptomycin-loaded PCL microparticles on mature biofilms was performed by fluorescence in situ hybridization. Fluorescence in situ hybridization showed an important reduction in MRSA biofilm, whereas S. epidermidis biofilms, although inhibited, were not eradicated. In addition, an important attachment of the microparticles to MRSA and S. epidermidis biofilms was observed. Finally, all formulations proved to be biocompatible with both ISO compliant L929 fibroblasts and human MG63 osteoblast-like cells

    TOF method in plasma potential measurements by HIBD

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    The heavy ion beam diagnostic (HIBD) developed for the tokamak ISTTOK (R = 0.46 m, a = 0.085 m, B = 0.5 T, I = 6-9 kA) is based on a multiple cell array detector (MCAD), which collects simultaneously a “fan” of secondary ions originated along a primary beam trajectory in collisions with the plasma electrons and separated by the magnetic field of the tokamak. Utilization of the traditional electrostatic energy spectrographs for the plasma potential measurements in experiments with MCAD is very complicated. This paper presents the current results of adaptation and mastering of the alternative time-of-flight (TOF) technique. Three schemes of the measurements are considered: i) “integral” scheme of the average plasma potential measurements by a pulsed primary beam, ii) “quasi-local” scheme of the measurements of plasma potential drop between neighbouring sample volumes, and iii) “local” scheme of plasma potential profile measurements. The electronics used in TOF energy analyzer (TOFEA) consist of charge sensitive and fast shaping amplifiers, constant fraction discriminator and time-toamplitude converter with resolution ∆t/t = 10⁻⁴. The TOFEA resolution ∆t/t = 3×10⁻⁴ has been achieved in mastering experiments with a pulsed (250 ns) primary beam carried out to the primary detector in magnetic field of the tokamak. With plasma the resolution is reduced 2.5 times due to decreasing of signal-to-noise ratio caused by plasma loading of MCAD. The changes of the average plasma potential during discharges with minor disruptions have been obtained by TOF energy analysis. The results of this experiment allow to conclude the reliability of TOF technique in plasma potential measurements by HIBD with MCAD. On the base of the obtained data and experience a four-channel TOFEA for the plasma potential profile measurements has been elaborated

    Reductive nanometric patterning of graphene oxide paper using electron beam lithography

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    Electron beam lithography (EBL) was used for preparing nanostructured reduced patterns on the GO paper surface, while preserving its mechanical resistance and flexibility. Different EBL parameters, like dose and time of exposure for patterning were tested. SEM analysis showed the consequent increase of contrast of the reduced stripes on the patterned regions due to the increase of electron beam doses. Moreover, surface potential microscopy experiments also exhibited a clear contrast between the patterned and non-patterned regions. Structural analysis of the patterned paper through X-ray diffraction and nanoindentation showed that the interlayer distance between GO sheets decreases after reduction allowing the increase of the Hardness and Young modulus that makes this material able to be manipulated and integrated on different devices. Furthermore, we also observe that exposed areas to electron beam reduction process show an increase in the electrical conductivity up to 3 × 104 times. The developed flexible GO films can have interesting applications such as biosensors or templates for inducing tissue regeneration, by providing a surface with differently patterned cues with contrasting electron mobility. Preliminary in vitro studies with L929 fibroblasts support the cytocompatible nature of this patterned GO paper.Gil Gonçalves thanks the Fundação para a Ciência e a Tecnologia for the PostDoc grant (SFRH/BDP/84419/2012). P.A.A.P.M. acknowledge the FCT/MCTES for a research contract under the Program Investigator 2013 (IF/00917/2013/CP1162/CT0016) and TEMA – Centre for Mechanical Technology and Automation (UID/EMS/00481/2013), financed by national funds through the FCT/MEC. I.B. wish to acknowledge the Portuguese Foundation for Science and Technology for the financial support (grant IF/00582/2015). H·I·S.N. acknowledges CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The biological studies of this work have been funded by the Ministerio de Economía y Competitividad and the Fondo Europeo de Desarrollo Regional (MAT2016-78857-R, MINECO/FEDER, UE). AGM and MCS acknowledge ISCIII-MINECO-FEDER for respective contracts. Authors would like to thank Dr M. Teresa Portolés from the Biochemistry and Molecular Biology Department at Universidad Complutense de Madrid for the generous supply of L929 fibroblasts. Dr José Ángel Rodríguez and Dr Javier Mazarío from the Service of Microscopy and Image Analysis at the Hospital Nacional de Parapléjicos are acknowledged for assistance with CLSM studies and Dr Enrique Rodríguez from the Servicio Interdepartamental de Investigación at the Universidad Autónoma de Madrid for SEM studies.info:eu-repo/semantics/acceptedVersio

    Chemical Quality of Rainwater and Surface Runoff Water in the Proximity of the Abstractions That Supply the São Pedro do Sul Medical Spa (Portugal)

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    São Pedro do Sul medical spa provides health services using hot natural groundwater superiorly classified as natural mineral water. The main source of supply of that medical spa, has been over time, the Traditional Spring, which in recent decades has been systematically controlled, and shows spectacular constancy in its chemical quality, if there are no outside contaminations. Within the context presented, the detailed physical-chemical quality of rainwater and surface runoff water was studied, in the proximity of the Traditional Spring, as there is a potential for them to infiltrate at depth and evolve into the natural mineral water aquifer system. Thus, in the present chapter, after presenting the physical-chemical quality of the natural mineral water from the Traditional Spring, as well as some elements of the literature on the physical-chemical quality of rainwater, the methodology of work is followed, and then the results obtained from the physical-chemical composition of rainwater and surface run-off water are presented and discussed, comparing them with the quality of the water from the Traditional Spring. Finally, the main conclusions are presented, and some recommendations are made on research into potential sources of pollution, which justify the poor quality of the rainwater studied

    Sistema de oscilometria de impulso em pediatria: revisão de literatura

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    Introduction: impulse oscillometry (IOS) is considered a method of evaluation of respiratory mechanics, and being non-invasive, has been increasingly mentioned in the care and research of pediatric patients. Studies have considered the interest of determining reference values and check the IOS relationship with other methods of respiratory assessment.Objective: to present an update of the literature regarding the system, technical criteria and interpretation of data, as well as the relationship of the system with other methods of respiratory assessment and its clinical applicability.Method: literature review with consultation in the databases MEDLINE / PubMed and Ebsco, using the keywords: “impulse oscillometry”, "reference  values” and “child”. It was considered all material with information about the equipment, their indications and application as an evaluation tool in different clinical situations.Results: 45 documents were identified, (41 trials and 4 reviews), supplemented with 20 papers (1 guideline, 1 manual on equipment and 18 articles on the subject). This material was characterized by approaching the equipment, its parameters evaluation, performance technique and positioning of the patient during the examination, criteria for acceptability and reproducibility, and interpretation of the data obtained. There are several publications of this tool in the evaluation of respiratory mechanics disorders such as asthma and cystic fibrosis, and making on reference values in healthy children. Conclusion: IOS is a relatively new feature, whose indication  in pediatrics has been increasing, but still required investigations, both technical and clinical investigations.Introdução: a oscilometria de impulso (IOS) é considerado um método de avaliação da mecânica respiratória, e por ser não invasivo, vem sendo crescentemente indicado na assistência e investigação do paciente pediátrico. Estudos tem tido como interesse a determinação de valores de referência e a verificação da relação do IOS com outros métodos de avaliação respiratória. Objetivo: Apresentar uma atualização da literatura quanto ao sistema, critérios técnicos e interpretação de dados, bem como, a relação do sistema com outros métodos de avaliação respiratória e sua aplicabilidade clínica.Método: revisão bibliográfica com consulta nas bases de dados MEDLINE/PubMed e Ebsco, utilizando as palavras-chaves: “impulse oscillometry”, “reference values” e “child”. Considerou-se todo material com informações sobre o equipamento, suas indicações e aplicação como instrumento de avaliação em diferentes situações clínicas.Resultados: foram identificados 45 documentos, sendo 41 ensaios clínicos e 4 revisões, complementados com 20 trabalhos: 1 guideline, 1 manual sobre o equipamento e 18 artigos referentes ao tema. Esse material foi caracterizado por abordar o equipamento, seus parâmetros de avaliação, técnica de execução e posicionamento do paciente durante o exame, critérios de aceitabilidade e reprodutibilidade e interpretação dos dados obtidos. São várias as publicações dessa ferramenta na avaliação da mecânica respiratória de disfunções como asma e fibrose cística e geração de valores de referência em crianças saudáveis.Conclusão: o IOS é um recurso relativamente novo, cuja indicação em pediatriatem sido crescente, mas que ainda carece investigações, tanto técnicas quanto clínicas

    Semigroup Closures of Finite Rank Symmetric Inverse Semigroups

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    We introduce the notion of semigroup with a tight ideal series and investigate their closures in semitopological semigroups, particularly inverse semigroups with continuous inversion. As a corollary we show that the symmetric inverse semigroup of finite transformations Iλn\mathscr{I}_\lambda^n of the rank n\leqslant n is algebraically closed in the class of (semi)topological inverse semigroups with continuous inversion. We also derive related results about the nonexistence of (partial) compactifications of classes of semigroups that we consider.Comment: With the participation of the new coauthor - Jimmie Lawson - the manuscript has been substantially revised and expanded. Accordingly, we have also changed the manuscript titl

    Evaluation of the potential association of SOHLH2 polymorphisms with non-obstructive azoospermia susceptibility in a large European population

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    Non-obstructive azoospermia (NOA) or spermatogenic failure is a complex disease with an important genetic component that causes infertility in men. Known genetic factors associated with NOA include AZF microdeletions of the Y chromosome or karyotype abnormalities; however, most causes of NOA are idiopathic. During the last decade, a large list of associations between single-nucleotide polymorphisms (SNP) and NOA have been reported. However, most of the genetic studies have been performed only in Asian populations. We aimed to evaluate whether the previously described association in Han Chinese between NOA and two SNPs of the SOHLH2 gene (involved in the spermatogenesis process) may also confer risk for NOA in a population of European ancestry. We genotyped a total of 551 NOA patients (218 from Portugal and 333 from Spain) and 1,050 fertile controls (226 from Portugal and 824 from Spain) for the genetic variants rs1328626 and rs6563386 using TaqMan assays. To test for association, we compared the allele and genotype frequencies between cases and controls using an additive model. A haplotype analysis and a meta-analysis using the inverse variance method with our data and those of the original Asian study were also performed. No statistically significant differences were observed in any of the analyses described above. Therefore, considering the high statistical power of our study, it is not likely that the two analysed SOHLH2 genetic variants are related with an increase susceptibility to NOA in the European population.info:eu-repo/semantics/publishedVersio

    Molecular richness and biotechnological potential of bacteria cultured from Irciniidae sponges in the north-east Atlantic

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    Several bioactive compounds originally isolated from marine sponges have been later ascribed or suggested to be synthesized by their symbionts. The cultivation of sponge-associated bacteria provides one possible route to the discovery of these metabolites. Here, we determine the bacterial richness cultured from two irciniid sponge species, Sarcotragus spinosulus and Ircinia variabilis, and ascertain their biotechnological potential. A total of 279 isolates were identified from 13 sponge specimens. These were classified into 17 genera - with Pseudovibrio, Ruegeria and Vibrio as the most dominant - and 3 to 10 putatively new bacterial species. While 16S rRNA gene sequencing identified 29 bacterial phylotypes at the 'species' level (97% sequence similarity), whole-genome BOX-PCR fingerprinting uncovered 155 genotypes, unveiling patterns of specimen-dependent occurrence of prevailing bacterial genomes across sponge individuals. Among the BOX-PCR genotypes recovered, 34% were active against clinically relevant strains, with Vibrio isolates producing the most active antagonistic effect. Several Pseudovibrio genotypes showed the presence of polyketide synthase (PKS) genes, and these were for the first time detected in isolates of the genus Aquimarina (Bacteroidetes). Our results highlight great biotechnological potential and interest for the Irciniidae sponge family and their diversified bacterial genomes.Portuguese Foundation for Science and Technology (FCT) [PTDC/MAR/101431/2008]; FCT [SFRH/BD/60873/2009, SFRH/BPD/62946/2009
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