875 research outputs found

    Microbiology of Ventilator-Associated Pneumonia

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    Ventilator-associated pneumonia (VAP) is a pulmonary infection that appears after 2 days of endotracheal intubation and when invasive mechanical ventilation is used. VAP is considered the most common nosocomial infection in the intensive care unit (ICU) and presents high morbidity and mortality rates, principally when caused by multi-resistant bacteria. Several risk factors are associated with VAP, including the microbiota, advanced age, immunocompromising conditions, pulmonary illness, length of mechanical ventilation, the aspiration technique, tracheostomy, supine positioning, enteral feeding, previous antibiotic exposure, among other endogenous and exogenous factors. The main pathogens are Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacteriaceae members, which are considered potentially multidrug-resistant pathogens. Conventional microbiology methods continue to be used for laboratory diagnosis. However, it is necessary to validate rapid and accurate laboratory methods, such as molecular assays that detect multiple gene sequences of a wide range of bacterial species and resistance markers. Therefore, the objective of this chapter is to review and update several aspects related to VAP, including risk factors, etiology, laboratory diagnosis, bacterial virulence and VAP severity, and antibiotic susceptibility

    Efficiency comparison of different DC-DC converter architectures for a power supply of a LiDAR system

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    LiDAR (Light Detection And Ranging) is a technology used to meas-ure distances to objects. Internally, a LiDAR system is constituted by several components, including a power supply, which is responsible to provide the dis-tinct voltage levels necessary for all the components. In this context, this paper presents an efficiency comparison of three different DC-DC converter architec-tures for a LiDAR system, each one composed of three DC-DC converters: in parallel; in cascade; and hybrid (mix of parallel and cascade). The topology of the adopted integrated DC-DC converters is the synchronous buck Switched-Mode Power Supply (SMPS), which is a modified version of the basic buck SMPS topology. Three distinct SMPSs were considered: LM5146-Q1, LM5116, and TPS548A20RVER. These SMPSs were selected according to the require-ments of voltage levels, namely, 12 V, 5 V, and 3.3 V. Along the paper, the prin-ciple of operation of the SMPSs is presented, as well as the evaluation results obtained for different operating powers, allowing to establish a comprehensive efficiency comparison.This work has been supported by national funds through FCT—Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/00319/2020, and also European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project nº 037902; Funding Reference: POCI-01-0247-FEDER-037902]

    New insights into the antimicrobial action of cinnamaldehyde towards escherichia coli and its effects on intestinal colonization of mice

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    Escherichia coli is responsible for cases of diarrhea around the world, and some studies have shown the benefits of cinnamaldehyde in the treatment of bacterial disease. Therefore, the objective of this study was to evaluate the effects of cinnamaldehyde in mice colonized by pathogenic E. coli, as well as to provide more insights into its antimicrobial action mechanism. After determination of minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations, the interference of cinnamaldehyde in macromolecular pathways (synthesis of DNA, RNA, protein, and cell wall) was measured by incorporation of radioisotopes. The anti-adhesive properties of cinnamaldehyde towards E. coli 042 were evaluated using human epithelial type 2 (HEp-2) cells. Intestinal colonization was tested on mice, and the effect of cinnamaldehyde on Tenebrio molitor larvae. Cinnamaldehyde showed MIC and MBC values of 780 μg/mL and 1560 μg/mL, respectively; reduced the adhesion of E. coli 042 on HEp-2 cells; and affected all the synthetic pathways evaluated, suggesting that compost impairs the membrane/cell wall structure leading bacteria to total collapse. No effect on the expression of genes related to the SOS pathway (sulA and dinB1) was observed. The compound did not interfere with cell viability and was not toxic against T. molitor larvae. In addition, cinnamaldehyde-treated mice exhibited lower levels of colonization by E. coli 042 than the untreated group. Therefore, the results show that cinnamaldehyde is effective in treating the pathogenic E. coli strain 042 and confirm it as a promising lead molecule for the development of antimicrobial agents

    Prophylactic Treatment With Simvastatin Modulates the Immune Response and Increases Animal Survival Following Lethal Sepsis Infection

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    Chronic use of statins may have anti-inflammatory action, promoting immunomodulation and survival in patients with sepsis. This study aimed to analyze the effects of pretreatment with simvastatin in lethal sepsis induced by cecal ligation and puncture (CLP). Male Swiss mice received prophylactic treatment with simvastatin or pyrogen-free water orally in a single daily dose for 30 days. After this period, the CLP was performed. Naïve and Sham groups were performed as non-infected controls. Animal survival was monitored for 60 h after the CLP. Half of mice were euthanized after 12 h to analyze colony-forming units (CFUs); hematological parameters; production of IL-10, IL-12, IL-6, TNF-α, IFN-γ, and MCP-1; cell counts on peritoneum, bronchoalveolar lavage (BAL), bone marrow, spleen, and mesenteric lymph node; immunephenotyping of T cells and antigen presenting cells and production of hydrogen peroxide (H2O2). Simvastatin induced an increase in survival and a decrease in the CFU count on peritoneum and on BAL cells number, especially lymphocytes. There was an increase in the platelets and lymphocytes number in the Simvastatin group when compared to the CLP group. Simvastatin induced a greater activation and proliferation of CD4+ T cells, as well as an increase in IL-6 and MCP-1 production, in chemotaxis to the peritoneum and in H2O2 secretion at this site. These data suggest that simvastatin has an impact on the survival of animals, as well as immunomodulatory effects in sepsis induced by CLP in mice

    BioNoMo. The biodiversity network of Mozambique

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    Mozambique biodiversity richness plays a pivotal role to achieve the sustainable development of the country. However, Mozambique's flora and fauna diversity still remains broadly unknown and poorly documented. To properly address this issue, one of the strategic needs expressed by the Mozambican institutions was the development of a national biodiversity data repository to aggregate, manage and make data available online. Thus, a sustainable infrastructure for the standardisation, aggregation, organisation and sharing of primary biodiversity data was developed. Named the "Biodiversity Network of Mozambique" (BioNoMo), such a tool serves as a national repository of biodiversity data and aggregates occurrence records of plants and animals in the country obtained from floristic and faunistic observations and from specimens of biological collections. In this paper, the authors present the structure and data of BioNoMO, including software details, the process of data gathering and aggregation, the taxonomic coverage and the WebGIS development. Currently, aggregating a total of 273,172 records, including 85,092 occurrence records of plants and 188,080 occurrence records of animals (41.2% terrestrial, 58,8% aquatic), BioNoMo represents the largest aggregator of primary biodiversity data in Mozambique and it is planned to grow further by aggregating new datasets

    MOONS: a Multi-Object Optical and Near-infrared Spectrograph for the VLT

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    MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope (VLT), selected by ESO for a Phase A study. The baseline design consists of 1000 fibers deployable over a field of view of 500 square arcmin, the largest patrol field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.8um-1.8um and two resolution modes: medium resolution and high resolution. In the medium resolution mode (R=4,000-6,000) the entire wavelength range 0.8um-1.8um is observed simultaneously, while the high resolution mode covers simultaneously three selected spectral regions: one around the CaII triplet (at R=8,000) to measure radial velocities, and two regions at R=20,000 one in the J-band and one in the H-band, for detailed measurements of chemical abundances. The grasp of the 8.2m Very Large Telescope (VLT) combined with the large multiplex and wavelength coverage of MOONS - extending into the near-IR - will provide the observational power necessary to study galaxy formation and evolution over the entire history of the Universe, from our Milky Way, through the redshift desert and up to the epoch of re-ionization at z>8-9. At the same time, the high spectral resolution mode will allow astronomers to study chemical abundances of stars in our Galaxy, in particular in the highly obscured regions of the Bulge, and provide the necessary follow-up of the Gaia mission. Such characteristics and versatility make MOONS the long-awaited workhorse near-IR MOS for the VLT, which will perfectly complement optical spectroscopy performed by FLAMES and VIMOS.Comment: 9 pages, 5 figures. To appear in the proceedings of the SPIE Astronomical Instrumentation + Telescopes conference, Amsterdam, 201
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