323 research outputs found

    Characterization and analysis of filled knitted fabric formworks for advanced manufacturing of composite structures

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    An alternative construction methodology has been raising interest, consisting of employing fabrics as formworks. The implementation of flexible formworks allows the production of highly optimized organic structures, avoiding the use of unnecessary materials and consequently reducing construction loads, costs and waste. This study aims to integrate the experimental characterization of the mechanical behaviour of the knitted textiles used as formworks, the mechanical and deformational behaviour of the formworks while being filled with fresh mortar, and the numerical simulation of the multi-step process leading to the final structure. The integration of these different processes is essential for a sound design of this composite system as a construction strategy. To this end, this investigation identified several aspects, related to either experimental or computational mechanics that are relevant to the topic and should be further investigated, with the aim of a future integrated material and structural design approach.ERDF -European Regional Development Fund(undefined

    Bacteriophage-receptor binding proteins for multiplex detection of Staphylococcus and Enterococcus in blood

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    Health care-associated infections (HCAIs) affect hundreds of millions of patients, representing a significant burden for public health. They are usually associated to multidrug resistant bacteria, which increases their incidence and severity. Bloodstream infections (BSIs) are among the most frequent and life-threatening HCAIs, with Enterococcus and Staphylococcus among the most common isolated pathogens. The correct and fast identification of the etiological agents is crucial for clinical decision-making, allowing to rapidly select the appropriate antimicrobial and to prevent from overuse and misuse of antibiotics and the consequent increase in antimicrobial resistance. Conventional culture methods are still the gold standard to identify these pathogens, however are time-consuming and may lead to erroneous diagnosis, which compromises an efficient treatment. (Bacterio)phage receptor binding proteins (RBPs) are the structures responsible for the high specificity conferred to phages against bacteria and thus are very attractive biorecognition elements with high potential for specific detection and identification of pathogens. Taking into account all these facts, we have designed and developed a new, fast, accurate, reliable and unskilled diagnostic method based on newly identified phage RBPs and spectrofluorometric techniques that allows the multiplex detection of Enterococcus and Staphylococcus in blood samples in less than 1.5 hours after an enrichment step.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the project “Phages‐on‐chip” PTDC/BTM‐SAL/32442/2017 (POCI‐01‐0145‐FEDER‐032442) and the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE‐01‐0145‐FEDER‐000004) funded by the European Regional Development Fund under the scope of Norte2020 − Programa Operacional Regional do Norte. Catarina Nogueira, Ana Brandão and Susana Costa were supported by the FCT grants PD/BD/143037/2018, SFRH/BD/133193/2017 and SFRH/BD/130098/2017, respectively. We would also like to acknowledge Professor Hermínia de Lencastre, Doctor Carina Almeida and Doctor Nuno Cerca for gently providing some of the strains used in this study. We acknowledge Professor Paulo Freitas for providing some of the infrastructures to perform the experiments.info:eu-repo/semantics/publishedVersio

    Routine screening of harmful microorganisms in beach sands: implications to public health

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    Beaches worldwide provide recreational opportunities to hundreds of millions of people and serve as important components of coastal economies. Beach water is often monitored for microbiological quality to detect the presence of indicators of human sewage contamination so as to prevent public health outbreaks associated with water contact. However, growing evidence suggests that beach sand can harbor microbes harmful to human health, often in concentrations greater than the beach water. Currently, there are no standards for monitoring, sampling, analyzing, or managing beach sand quality. In addition to indicator microbes, growing evidence has identified pathogenic bacteria, viruses, and fungi in a variety of beach sands worldwide. The public health threat associated with these populations through direct and indirect contact is unknown because so little research has been conducted relating to health outcomes associated with sand quality. In this manuscript, we present the consensus findings of a workshop of experts convened in Lisbon, Portugal to discuss the current state of knowledge on beach sand microbiological quality and to develop suggestions for standardizing the evaluation of sand at coastal beaches. The expert group at the "Microareias 2012" workshop recommends that 1) beach sand should be screened for a variety of pathogens harmful to human health, and sand monitoring should then be initiated alongside regular water monitoring; 2) sampling and analysis protocols should be standardized to allow proper comparisons among beach locations; and 3) further studies are needed to estimate human health risk with exposure to contaminated beach sand. Much of the manuscript is focused on research specific to Portugal, but similar results have been found elsewhere, and the findings have worldwide implications

    Routine screening of harmful microorganisms in beach sands: implications to public health

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    Beaches worldwide provide recreational opportunities to hundreds of millions of people and serve as important components of coastal economies. Beach water is often monitored for microbiological quality to detect the presence of indicators of human sewage contamination so as to prevent public health outbreaks associated with water contact. However, growing evidence suggests that beach sand can harbor microbes harmful to human health, often in concentrations greater than the beach water. Currently, there are no standards for monitoring, sampling, analyzing, or managing beach sand quality. In addition to indicator microbes, growing evidence has identified pathogenic bacteria, viruses, and fungi in a variety of beach sands worldwide. The public health threat associated with these populations through direct and indirect contact is unknown because so little research has been conducted relating to health outcomes associated with sand quality. In this manuscript, we present the consensus findings of a workshop of experts convened in Lisbon, Portugal to discuss the current state of knowledge on beach sand microbiological quality and to develop suggestions for standardizing the evaluation of sand at coastal beaches. The expert group at the "Microareias 2012" workshop recommends that 1) beach sand should be screened for a variety of pathogens harmful to human health, and sand monitoring should then be initiated alongside regular water monitoring; 2) sampling and analysis protocols should be standardized to allow proper comparisons among beach locations; and 3) further studies are needed to estimate human health risk with exposure to contaminated beach sand. Much of the manuscript is focused on research specific to Portugal, but similar results have been found elsewhere, and the findings have worldwide implications

    Effect of a gel containing pilocarpine on vaginal atrophy in castrated rats

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    OBJECTIVES: To evaluate the effect of Carbopol gel formulations containing pilocarpine on the morphology and morphometry of the vaginal epithelium of castrated rats. METHODS: Thirty-one female Wistar-Hannover rats were randomly divided into four groups: the control Groups I (n=7, rats in persistent estrus; positive controls) and II (n=7, castrated rats, negative controls) and the experimental Groups, III (n=8) and IV (n=9). Persistent estrus (Group I) was achieved with a subcutaneous injection of testosterone propionate on the second postnatal day. At 90 days postnatal, rats in Groups II, III and IV were castrated and treated vaginally for 14 days with Carbopol gel (vehicle alone) or Carbopol gel containing 5% and 15% pilocarpine, respectively. Next, all of the animals were euthanized and their vaginas were removed for histological evaluation. A non-parametric test with a weighted linear regression model was used for data analysis (

    Accurate, Fast and Cost-Effective Diagnostic Test for\ud Monosomy 1p36 Using Real-Time Quantitative PCR

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    Monosomy 1p36 is considered the most common subtelomeric deletion syndrome in humans and it accounts for 0.5–0.7% of all\ud the cases of idiopathic intellectual disability. The molecular diagnosis is often made by microarray-based comparative genomic\ud hybridization (aCGH), which has the drawback of being a high-cost technique. However, patients with classic monosomy 1p36\ud share some typical clinical characteristics that, together with its common prevalence, justify the development of a less expensive,\ud targeted diagnostic method. In this study, we developed a simple, rapid, and inexpensive real-time quantitative PCR (qPCR) assay\ud for targeted diagnosis of monosomy 1p36, easily accessible for low-budget laboratories in developing countries. For this, we have\ud chosen two target genes which are deleted in the majority of patients with monosomy 1p36: PRKCZ and SKI. In total, 39 patients\ud previously diagnosed with monosomy 1p36 by aCGH, fluorescentin situhybridization (FISH), and/or multiplex ligation-dependent\ud probe amplification (MLPA) all tested positive on our qPCR assay. By simultaneously using these two genes we have been able to\ud detect 1p36 deletions with 100% sensitivity and 100% specificity. We conclude that qPCR of PRKCZ and SKI is a fast and accurate\ud diagnostic test for monosomy 1p36, costing less than 10 US dollars in reagent costs

    Proteomic profiling of Burkholderia cenocepacia clonal isolates with different virulence potential retrieved from a cystic fibrosis patient during chronic lung infection

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    Respiratory infections with Burkholderia cepacia complex (Bcc) bacteria in cystic fibrosis (CF) are associated with a worse prognosis and increased risk of death. In this work, we assessed the virulence potential of three B. cenocepacia clonal isolates obtained from a CF patient between the onset of infection (isolate IST439) and before death with cepacia syndrome 3.5 years later (isolate IST4113 followed by IST4134), based on their ability to invade epithelial cells and compromise epithelial monolayer integrity. The two clonal isolates retrieved during late-stage disease were significantly more virulent than IST439. Proteomic profiling by 2-D DIGE of the last isolate recovered before the patient's death, IST4134, and clonal isolate IST439, was performed and compared with a prior analysis of IST4113 vs. IST439. The cytoplasmic and membrane-associated enriched fractions were examined and 52 proteins were found to be similarly altered in the two last isolates compared with IST439. These proteins are involved in metabolic functions, nucleotide synthesis, translation and protein folding, cell envelope biogenesis and iron homeostasis. Results are suggestive of the important role played by metabolic reprogramming in the virulence potential and persistence of B. cenocepacia, in particular regarding bacterial adaptation to microaerophilic conditions. Also, the content of the virulence determinant AidA was higher in the last 2 isolates. Significant levels of siderophores were found to be secreted by the three clonal isolates in an iron-depleted environment, but the two late isolates were more tolerant to low iron concentrations than IST439, consistent with the relative abundance of proteins involved in iron uptake.This work was supported by FEDER and FCT – Fundação para a Ciência e a Tecnologia (contract PEst-OE/EQB/LA0023/2011_ research line: Systems and Synthetic Biology; PhD grant to A.M. – SFRH/BD/37012/2007, and PD grants to S.S. – SFRH/BPD/75483/2010 and C.C. – SFRH/BPD/ 81220/2011. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

    Antimicrobial Photodynamic Therapy: Study of Bacterial Recovery Viability and Potential Development of Resistance after Treatment

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    Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py+-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py+-Me-PF (5.0 μM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m−2) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 μM of Tri-Py+-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py+-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process

    Genomic Expression Analysis Reveals Strategies of Burkholderia cenocepacia to Adapt to Cystic Fibrosis Patients' Airways and Antimicrobial Therapy

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    Pulmonary colonization of cystic fibrosis (CF) patients with Burkholderia cenocepacia or other bacteria of the Burkholderia cepacia complex (Bcc) is associated with worse prognosis and increased risk of death. During colonization, the bacteria may evolve under the stressing selection pressures exerted in the CF lung, in particular, those resulting from challenges of the host immune defenses, antimicrobial therapy, nutrient availability and oxygen limitation. Understanding the adaptive mechanisms that promote successful colonization and long-term survival of B. cenocepacia in the CF lung is essential for an improved therapeutic outcome of chronic infections. To get mechanistic insights into these adaptive strategies a transcriptomic analysis, based on DNA microarrays, was explored in this study. The genomic expression levels in two clonal variants isolated during long-term colonization of a CF patient who died from the cepacia syndrome were compared. One of the isolates examined, IST439, is the first B. cenocepacia isolate retrieved from the patient and the other isolate, IST4113, was obtained three years later and is more resistant to different classes of antimicrobials. Approximately 1000 genes were found to be differently expressed in the two clonal variants reflecting a marked reprogramming of genomic expression. The up-regulated genes in IST4113 include those involved in translation, iron uptake (in particular, in ornibactin biosynthesis), efflux of drugs and in adhesion to epithelial lung tissue and to mucin. Alterations related with adaptation to the nutritional environment of the CF lung and to an oxygen-limited environment are also suggested to be a key feature of transcriptional reprogramming occurring during long-term colonization, antibiotic therapy and the progression of the disease
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