1,656 research outputs found

    Thin-layer nanofiltration membranes using engineered biopolymers for seawater desalination pre-treatment processes

    Get PDF
    Nowadays water demand already exceeds supply and water scarcity is a global problem. So it is necessary to develop novel technologies to be able to use poorer quality source waters for drinking water production. Once considered as an expensive, ultimate solution for water supply, desalination is becoming affordable. The two most commonly used seawater desalination methods are Multi-stage Flash Distillation (MSF) and Seawater Reverse Osmosis (SWRO). SWRO is less energy demanding compared to MSF, which makes it economically attractive. However there is no backpulsing of the expensive and delicate reverse osmosis (RO) membranes with air or water, so they are susceptible to fouling, causing the loss of their performance. Therefore cleaning the feed water to the highest level possible by nanofiltration, before it reaches the RO membranes would highly increase the efficiency of the process. Nanofiltration (NF) as a feed pre-treatment step is a pressure driven membrane separation process that takes place on a selective layer formed by a semipermeable membrane with properties between RO and ultrafiltration. The objective of this project is the developement of highly efficient thin-film composite (TFC) membranes for SWRO pre-treatment processes based on low-fouling cyanobacterial extracellular polymeric substances (EPS). TFC membranes combine high flux and mechanical strenght, and they are expected to be the key components of any water purification technology in the future. Cyanobacterial EPS are complex heteropolysaccharides with putative antimicrobial and antiviral properties and a particular affinity to bind metal ions [1,2].Within this work, the unicellular N2-fixing marine cyanobacterium Cyanothece sp. CCY 0110 was chosen for RPS production, since it is among the most efficient released polysaccharide (RPS) producers and the polymer has been previously extensively characterised [3]. RPS was produced by growing Cyanothece CCY 0110 in 10L bioreactors, in conditions previously defined and the polymer was isolated following the standard methodology [3]. A polyvinyl alcohol (PVA) / cyanobacterial EPS blend nanofibrous membranes were fabricated by electrospinning using polyvinylidene fluoride (PVDF) as a basal membrane, in order to obtain thin-layer composite nanofiltration membranes. The production of the nanofibers using EPS and PVA as plasticizer in different ratios was produced in a NF-103 MECC Nanon electrospinning equipment with an applied electric field between 15 and 25 kV and a flow of 0,2 mL/h. Morphological, mechanical, chemical and thermal characterization of the electrospun fibers deposited on the basal membranes, were evaluated by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), dynamical and mechanical analysis (DMA), thermogravimetry (TGA) and differential scanning calorimetry (DSC). The AFM and SEM results show the presence of fibers with dimensions between 54 and 121 nm with low bead formation. In the EDS analysis presence of sulfur elements was observed confirming the inclusion of EPS in the nanofibers. The morphology and diameter of the nanofibers were mainly affected by the concentration of the blend solution and the weight ratio of the blend, respectively. The best PVA/EPS nanofibers were achieved in a ratio of 12 % PVA and 0.4 % EPS. The solution conductivity was ranging 1500 to 3500 μS/cm with a viscosity of about 100 to 500 cP. The DMA results confirmed the miscibility of PVA/EPS blends. The elastic modulus of the nanocomposite mats increased significantly as a consequence of the reinforcing effect of EPS. Thermal and mechanical analysis demonstrated that there were strong intermolecular hydrogen bonds between the molecules EPS-PVA in the blends. The heat-treated electrospun blended membranes showed better tensile mechanical properties when compared with PVA alone, and resisted more against disintegration. A lab-scale nanofiltration was performed in a bench stainless steel Sterlitech tangential flow stirred cell (200 mL) connected to an air pressure system that allow pressure driven filtration up to 10 BAR. Bactericidal activity and biofilm formation were tested using Escherichia coli and Sthaphylococcus aureus as pathogenic microorganisms

    Castleman disease

    Get PDF
    Apresentam-se dois casos clínicos de doença de Castleman, situação rara e de difícil diagnóstico, um na forma multissistémica e outro na forma localizada, um na variante plasmocitária e outro na de tipo misto. Nos dois casos, o diagnóstico só foi possível por exame histológico. Salienta-se a grande variabilidade na sintomatologia e prognóstico, de acordo com a variante histológica e a forma de apresentação.We report two cases ofCastleman disease, a systemic and a localized formo Diagnosis was based on the histological findings. The great variability in symptoms and prognosis, according to the histological variant and presentation form is emphasized

    Root causes and outcomes of postoperative pulmonary complications after abdominal surgery: A retrospective observational cohort study

    Get PDF
    FCT project IPOscore (DSAIPA/DS/0042/2018).Background: Postoperative pulmonary complications (PPCs) contribute significantly to overall postoperative morbidity and mortality. In abdominal surgery, PPCs remain frequent. The study aimed to analyze the profile and outcomes of PPCs in patients submitted to abdominal surgery and admitted in a Portuguese polyvalent intensive care unit. Methods: From January to December 2017 in the polyvalent intensive care unit of Hospital Garcia de Orta, Almada, Portugal, we conducted a retrospective, observational study of inpatients submitted to urgent or elective abdominal surgery who had severe PPCs. We evaluated the perioperative risk factors and associated mortality. Logistic regression was performed to find which perioperative risk factors were most important in the occurrence of PPCs. Results: Sixty patients (75% male) with a median age of 64.5 [47-81] years who were submitted to urgent or elective abdominal surgery were included in the analysis. Thirty-six patients (60%) developed PPCs within 48 h and twenty-four developed PPCs after 48 h. Pneumonia was the most frequent PPC in this sample. In this cohort, 48 patients developed acute respiratory failure and needed mechanical ventilation. In the emergency setting, peritonitis had the highest rate of PPCs. Electively operated patients who developed PPCs were mostly carriers of digestive malignancies. Thirty-day mortality was 21.7%. The risk of PPCs development in the first 48 h was related to the need for neuromuscular blocking drugs several times during surgery and preoperative abnormal arterial blood gases. Median abdominal surgical incision, long surgery duration, and high body mass index were associated with PPCs that occurred more than 48 h after surgery. The American Society of Anesthesiologists physical status score 4 and COPD/Asthma determined less mechanical ventilation needs since they were preoperatively optimized. Malnutrition (low albumin) before surgery was associated with 30-day mortality. Conclusion: PPCs after abdominal surgery are still a major problem since they have profound effects on outcomes. Our results suggest that programs before surgery, involve preoperative lifestyle changes, such as nutritional supplementation, exercise, stress reduction, and smoking cessation, were an effective strategy in mitigating postoperative complications by decreasing mortality.publishersversionpublishe

    The Health-Promoting Potential of Salix spp. Bark Polar Extracts: Key Insights on Phenolic Composition and In Vitro Bioactivity and Biocompatibility

    Get PDF
    Salix spp. have been exploited for energy generation, along with folk medicine use of bark extracts for antipyretic and analgesic benefits. Bark phenolic components, rather than salicin, have demonstrated interesting bioactivities, which may ensure the sustainable bioprospection of Salix bark. Therefore, this study highlights the detailed phenolic characterization, as well as the in vitro antioxidant, anti-hypertensive, Staphylococcus aureus growth inhibitory effects, and biocompatibility of Salix atrocinerea Brot., Salix fragilis L., and Salix viminalis L. bark polar extracts. Fifteen phenolic compounds were characterized by ultra-high-performance liquid chromatography-ultraviolet detection-mass spectrometry analysis, from which two flavan-3-ols, an acetophenone, five flavanones, and a flavonol were detected, for the first time, as their bark components. Salix bark extracts demonstrated strong free radical scavenging activity (5.58–23.62 µg mL−1 IC50 range), effective inhibition on angiotensin-I converting enzyme (58–84%), and S. aureus bactericidal action at 1250–2500 µg mL−1 (6–8 log CFU mL−1 reduction range). All tested Salix bark extracts did not show cytotoxic potential against Caco-2 cells, as well as S. atrocinerea Brot. and S. fragilis L. extracts at 625 and 1250 µg mL−1 against HaCaT and L929 cells. These valuable findings can pave innovative and safer food, nutraceutical, and/or cosmetic applications of Salix bark phenolic-containing fractions.info:eu-repo/semantics/publishedVersio

    A miniature inverted-repeat transposable element, AddIn-MITE, located inside a WD40 gene is conserved in Andropogoneae grasses

    Get PDF
    Miniature inverted-repeat transposable elements (MITEs) have been associated with genic regions in plant genomes and may play important roles in the regulation of nearby genes via recruitment of small RNAs (sRNA) to the MITEs loci. We identified eight families of MITEs in the sugarcane genome assembly with MITE-Hunter pipeline. These sequences were found to be upstream, downstream or inserted into 67 genic regions in the genome. The position of the most abundant MITE (Stowaway-like) in genic regions, which we call AddIn-MITE, was confirmed in a WD40 gene. The analysis of four monocot species showed conservation of the AddIn-MITE sequence, with a large number of copies in their genomes. We also investigated the conservation of the AddIn-MITE’ position in the WD40 genes from sorghum, maize and, in sugarcane cultivars and wild Saccharum species. In all analyzed plants, AddIn-MITE has located in WD40 intronic region. Furthermore, the role of AddIn-MITE-related sRNA in WD40 genic region was investigated. We found sRNAs preferentially mapped to the AddIn-MITE than to other regions in the WD40 gene in sugarcane. In addition, the analysis of the small RNA distribution patterns in the WD40 gene and the structure of AddIn-MITE, suggests that the MITE region is a proto-miRNA locus in sugarcane. Together, these data provide insights into the AddIn-MITE role in Andropogoneae grasses

    A behavioral test battery for mouse models of Angelman syndrome

    Get PDF
    Background: Angelman syndrome (AS) is a neurodevelopmental disorder caused by mutations affecting UBE3A function. AS is characterized by intellectual disability, impaired motor coordination, epilepsy, and behavioral abnormalities including autism spectrum disorder features. The development of treatments for AS heavily relies on the ability to test the efficacy of drugs in mouse models that show reliable, and preferably clinically relevant, phenotypes. We previously described a number of behavioral paradigms that assess phenotypes in the domains of motor performance, repetitive behavior, anxiety, and seizure susceptibility. Here, we set out to evaluate the robustness of these phenotypes when tested in a standardized test battery. We then used this behavioral test battery to assess the efficacy of minocycline and levodopa, which were recently tested in clinical trials of AS. Methods: We combined data of eight independent experiments involving 111 Ube3a mice and 120 wild-type littermate control mice. Using a meta-analysis, we determined the statistical power of the subtests and the effect of putative confounding factors, such as the effect of sex and of animal weight on rotarod performance. We further assessed the robustness of these phenotypes by comparing Ube3a mutants in different genetic backgrounds and by comparing the behavioral phenotypes of independently derived Ube3a-mutant lines. In addition, we investigated if the test battery allowed re-testing the same animals, which would allow a within-subject testing design. Results: We find that the test battery is robust across different Ube3a-mutant lines, but confirm and extend earlier studies that several phenotypes are very sensitive to genetic background. We further found that the audiogenic seizure susceptibility phenotype is fully reversible upon pharmacological treatment and highly suitable for dose-finding studies. In agreement with the clinical trial results, we found that minocycline and levodopa treatment of Ube3a mice did not show any sign of improved performance in our test battery. Conclusions: Our study provides a useful tool for preclinical drug testing to identify treatments for Angelman syndrome. Since the phenotypes are observed in several independently derived Ube3a lines, the test battery can also be employed to investigate the effect of specific Ube3a mutations on these phenotypes

    Geobotanical excursion guide of the XIII International Seminar Management and Biodiversity Conservation-Vale do Lobo, Loulé (Algarve-Portugal)

    Get PDF
    43 páginas, 10 figuras.[EN] This field guide was developed as part of the XIII International Seminar Management and Biodiversity Conservation – Vale do Lobo, Loulé (Algarve – Portugal), that aims to contribute for the scientific knowledge of the flora and vegetation of the Algarvian territories. The itinerary of the geobotanical excursion have been chosen to present the remarkable floristic richness and plant communities of three different landscape subunits: i) Faixa Litoral (dunes and saltmarshes of the Ancão Peninsula); ii) Barrocal (Nave do Barão); and, iii) Serra Algarvia (Caldeirão and Monchique mountains). For each sites the plant communities are briefly stated, as well as the vascular flora observed, including species with special conservation interest. Finally, we present the syntaxonomic scheme, and the floristic catalog of the field trip.[PO] No âmbito das atividades do XIII Seminário Internacional de Gestão e Conservação da Biodiversidade – Vale do Lobo, Loulé (Algarve – Portugal), desenvolveu-se o presente trabalho, com o objetivo de aprofundar o conhecimento da flora e vegetação dos locais a visitar no contexto do itinerário da excursão geobotânica aos territórios algarvios. Assim, a seleção dos locais de paragem procurou evidenciar a originalidade florística e fitocenótica de três sub-unidades paisagísticas de carácter e identidade distintas: i) Faixa Litoral (dunas e sapais da Península do Ancão); ii) Barrocal (Nave do Barão); e, iii) Serra Algarvia (Serra do Caldeirão e Serra de Monchique). Após uma breve descrição dos aspetos litológicos, das condições bioclimáticas e do enquadramento biogeográfico, evidenciam-se as associações vegetais e espécies presentes nas paragens realizadas, com identificação dos elementos florísticos com interesse para a conservação. Por último, tendo por base a descrição da vegetação, apresenta-se o esquema sintaxonómico, e um elenco florístico dos locais percorridos
    • …
    corecore