1,225 research outputs found

    Assessment of Lactobacillus crispatus´ role in vaginal infections: friend or foe?

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    Lactobacillus spp. are the most prevalent microorganisms in the vaginal milleu. Several probiotic mechanisms have been associated with Lactobacillus, but the most relevant one is lactate production – resulting in a low pH value, typical of the healthy vagina. However, its pathogenic state is still unknown. We aim to elucidate the role of a commensal vaginal microorganism, Lactobacillus crispatus, in vaginal infections. Twenty-four vaginal washes have been collected from women attending a gynaecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling. The distribution of bacterial species, and their prevalence was assessed by Next-Generation Sequencing of the 16S rRNA V4 region. In addition, L- and D-lactate concentration, and LDH enzymatic activity was quantified in all washes by a commercial kit. Detection of Candida spp. was performed by PCR. L. crispatus was dominant (>70%) in 11 out of 24 samples – diagnosed for vaginal atrophy (VA, 3), cytolytic vaginosis (CV, 2) and lactobacillosis (LB, 2). Lactate was increased in CV, LB and VA cases only. The remaining samples, diagnosed for vulvovaginal candidosis in its majority, had lower prevalence of L. crispatus; and lower to moderate lactate metabolite. There was not a direct relationship between LDH enzymatic activity and clinical diagnosis. L. crispatus dominance, associated with increased lactate production, was observed in CV, LB and VA cases. These results indicate that this microorganism might have a role in dysbiosis of the vagina associated with these specific pathologies.info:eu-repo/semantics/publishedVersio

    Role of Lactobacillus crispatus in vaginal infections: insights from metagenomics and metabolomics studies

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    Objective: Lactobacillus spp. constitute the most prevalent bacterial microorganism in the vaginal milleu. Several probiotic mechanisms have been associated with Lactobacillus, but the most relevant one is lactate production – resulting in a low pH value, typical of the healthy vagina. We aim to elucidate the role of a native vaginal microorganism, Lactobacillus crispatus, in vaginal infections. Methods: Twenty-four vaginal washes have been collected from women (mean 38±14 years of age) attending a gynecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling. The distribution of bacterial species, and their prevalence was assessed by next-generation sequencing of the 16S V4 region. In addition, lactate was quantified in all washes by a commercial kit. Results: L. crispatus was dominant (>70%) in 11 out of 24 samples – diagnosed for vaginal atrophy (VA, 3), cytolytic vaginosis (CV, 2), lactobacillosis (LB, 2) and vulvovaginal candidosis (VVC, 1). For three samples, diagnostic was inconclusive. Lactate was increased in CV, LB and VA cases only. One sample, diagnosed with VVC had 23% dominance of L. crispatus; and lower lactate metabolite. L. crispatus was not detected in the remaining 12 cases (6 VVC, 4 VA, 1 healthy and 1 inconclusive). Of these, only 5 samples had moderate lactate metabolite. Conclusions: L. crispatus dominance, associated with increased lactate production, was observed in CV, LB and VA cases. These results indicate that this microorganism might have a role in dysbiosis of the vagina associated with these specific pathologies.info:eu-repo/semantics/publishedVersio

    Lactobacillus crispatus as the etiological agent in cytolytic vaginosis

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    Introduction: Lactobacillus spp. dominate the vaginal niche but can also be involved in other vaginal dysbiosis, such as cytolytic vaginosis (CV), which remains poorly studied. It is characterized by a cryptic symptomatology, that often confounds the clinic. Goals: The aim of this work was to search for the etiological agent of CV, by studying the vaginal microbiome and metabolomics of women afflicted with this disease and compare it with women with other clinical diagnostic. Methods: Twenty-one vaginal washes have been collected from women attending a gynaecology consultation of a private clinic. The samples were categorized according with clinical diagnosis at the time of sampling (CV, 11; vulvovaginal candidosis, 8; Healthy, 2). The distribution of bacterial species, and their prevalence was assessed by next-generation sequencing of the 16S V4 region. In addition, total lactate D-lactic acid and L-lactic acid was quantified in all washes by a commercial kit, as well as lactate dehydrogenase (LDH) activity. Results: L. crispatus was dominant (>70%) in all CV samples. Lactate was increased in CV in comparison with other cases. The presence of D-lactic acid isomer was associated with presence of L. crispatus. LDH activity was increased in vaginal washes that tested positive for the presence of L. crispatus, however no direct association was found with CV cases. Discussion/Conclusions: The microbiome of women afflicted with CV was dominated in all cases by L. crispatus, contrarily with the results obtained for women diagnosed with other clinical symptomatology. In addition, the finding that an increase in D-lactic acid is associated with CV patients can be related to the role of L. crispatus in CV. The determination of LDH activity did not correlate exclusively with CV cases. On the other hand, D-lactic acid and total lactate quantification could be used as a valuable biomarker to diagnose this cryptic vaginal infection.info:eu-repo/semantics/publishedVersio

    X-ray diffraction and Raman study of nanogranular BaTiO3-CoFe2O4thin films deposited by laser ablation on Si/Pt substrates

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    Nanocomposite thin films composed by (BaTiO3)1-x-(CoFe2O4)x with different cobalt ferrite concentrations (x) have been deposited by pulsed laser ablation on platinum covered Si(001) substrates. The films structure was studied by X-ray diffraction and Raman spectroscopy. It was found that the CoFe2O4 phase unit cell was compressed along the growth direction of the films, and it relaxed with increasing x. The opposite behavior was observed in the BaTiO3 phase where the lattice parameters obtained from the X-ray measurements presented a progressive distortion of its unit cell with increasing x. The presence of the strain in the films induced a blueshift of the Raman peaks of CoFe2O4 that decreased with increasing CoFe2O4 concentration. Cation disorder in the cobalt ferrite was observed for lower x, where the nanograins are more isolated and subjected to more strain, which was progressively decreased for higher CoFe2O4 content in the films.This work has been financially supported by the Portuguese Foundation for Science and Technology (FCT), through the project POCI/CTM/60181/2004 and the Bilateral Research Action nºB48-06 between CRUP (Portugal) and British Council (UK)

    Nanogranular BaTiO3–CoFe2O4 thin films deposited by pulsed laser ablation

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    Detailed structural and magnetic measurements were performed on nanostructured composite thin films of cobalt ferrite (CoFe2O4 - magnetostrictive) dispersed in a barium titanate (BaTiO3 - piezoelectric) matrix, with different CoFe2O4 concentrations (ranging from x=20% to x=70%). The films were deposited by laser ablation on platinum covered Si(100). Their structure was studied by X-ray diffraction and Raman spectroscopy. The magnetic properties were measured with a SQUID magnetometer. The nanocomposite films were polycrystalline and composed by a mixture of tetragonal-BaTiO3 and CoFe2O4 with the cubic spinel structure. The lattice parameter of the CoFe2O4 phase varied from 8.26Ã… (x=20%) to 8.35Ã… (x=70%), and, comparing with bulk CoFe2O4, it was under compressive stress that relaxed as its concentration progressively increased. In the tetragonal-BaTiO3 phase, the lattice parameter a was contracted relative to the bulk phase and decreases with x. The lattice parameter c increased from 4.088 Ã… (x=20%) to 4.376 Ã… (x=70%), so that the BaTiO3 c axes was increasingly expanded as the quantity of the barium titanate phase was reduced. This behavior was the opposite of that observed in CoFe2O4. The magnetic measurements showed that the coercive fields decreased from 6.6 kOe (x=20%) to 2.3 kOe (x=70%) which was attributed to the progressive relaxation of the stress in the films as well as to the increase of particle agglomeration in bigger polycrystalline clusters with increasing cobalt ferrite concentration. For higher temperatures T=300 K the reduction of magnetocrystalline anisotropy induced a strong reduction of the coercive field.This work has been financially supported by the Portuguese Foundation for Science and Technology (FCT), through the project POCI/CTM/60181/2004

    Structural and magnetic properties of nanogranular BaTiO3-CoFe2O4 thin films deposited by laser ablation on Si/Pt substrates

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    Thin film nanogranular composites of cobalt ferrite (CoFe2O 4) dispersed in a barium titanate (BaTiO3) matrix were deposited by laser ablation with different cobalt ferrite concentrations (x). The films were polycrystalline and composed by a mixture of tetragonal- BáTiO3 and CoFe2O4 with the cubic spinnel structure. A slight (111) barium titanate phase orientation and (311) CoFe2O4 phase orientation was observed. As the concentration of the cobalt ferrite increased, the grain size of the BaTiO 3 phase decreased, from 91nm to 30nm, up to 50% CoFe 2O4 concentration, beyond which the BaTiO3 grain size take values in the range 30-35nm. On the other hand the cobalt ferrite grain size did not show a clear trend with increasing cobalt ferrite concentration, fluctuating in the range 25nm to 30nm. The lattice parameter of the CoFe2O4 phase increased with increasing x. However, it was always smaller than the bulk value indicating that, in the films, the cobalt ferrite was under compressive stress that was progressively relaxed with increasing CoFe2O4 concentration. The magnetic measurements showed a decrease of coercive field with increasing x, which was attributed to the relaxation of the stress in the films and to the increase of particle agglomeration in bigger polycrystalline clusters with increasing cobalt ferrite concentration.This work has been financially supported by the Portuguese Foundation for Science and Technology (FCT), through the project POCI/CTM/60181/2004

    A model to explain angular distributions of J/ψJ/\psi and ψ(2S)\psi(2S) decays into ΛΛ‾\Lambda\overline{\Lambda} and Σ0Σ‾0\Sigma^0\overline{\Sigma}^0

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    BESIII data show a particular angular distribution for the decay of the J/ψJ/\psi and ψ(2S)\psi(2S) mesons into the hyperons ΛΛ‾\Lambda\overline{\Lambda} and Σ0Σ‾0\Sigma^0\overline{\Sigma}^0. More in details the angular distribution of the decay ψ(2S)→Σ0Σ‾0\psi(2S) \to \Sigma^0\overline{\Sigma}^0 exhibits an opposite trend with respect to that of the other three channels: J/ψ→ΛΛ‾J/\psi \to \Lambda\overline{\Lambda}, J/ψ→Σ0Σ‾0J/\psi \to \Sigma^0\overline{\Sigma}^0 and ψ(2S)→ΛΛ‾\psi(2S) \to \Lambda\overline{\Lambda}. We define a model to explain the origin of this phenomenon.Comment: 6 pages, 7 figures, to be published in Chinese Physics

    Three-phase current-source shunt active power filter with solar photovoltaic grid interface

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    This paper presents the proposal of a three phase current source shunt active power filter (CS-SAPF) with photovoltaic grid interface. The proposed system combines the compensation of reactive power and harmonics with the injection of energy from a solar photovoltaic array into the electrical power grid. The proposed equipment presents the advantage of giving good use to the current source inverter, even when the solar photovoltaic array is not producing energy. The paper describes the control system of the CS SAPF, the energy injection control strategy, and the current harmonics and power factor compensation strategy. Simulation results to assess the performance of the proposed system are also presented.FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013

    A Cylindrical GEM Inner Tracker for the BESIII experiment at IHEP

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    The Beijing Electron Spectrometer III (BESIII) is a multipurpose detector that collects data provided by the collision in the Beijing Electron Positron Collider II (BEPCII), hosted at the Institute of High Energy Physics of Beijing. Since the beginning of its operation, BESIII has collected the world largest sample of J/{\psi} and {\psi}(2s). Due to the increase of the luminosity up to its nominal value of 10^33 cm-2 s-1 and aging effect, the MDC decreases its efficiency in the first layers up to 35% with respect to the value in 2014. Since BESIII has to take data up to 2022 with the chance to continue up to 2027, the Italian collaboration proposed to replace the inner part of the MDC with three independent layers of Cylindrical triple-GEM (CGEM). The CGEM-IT project will deploy several new features and innovation with respect the other current GEM based detector: the {\mu}TPC and analog readout, with time and charge measurements will allow to reach the 130 {\mu}m spatial resolution in 1 T magnetic field requested by the BESIII collaboration. In this proceeding, an update of the status of the project will be presented, with a particular focus on the results with planar and cylindrical prototypes with test beams data. These results are beyond the state of the art for GEM technology in magnetic field
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