303 research outputs found

    Analytical approach for the flexural analysis of RC beams strengthened with prestressed CFRP

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    The objective of this paper is to propose a simplified analytical approach to predict the flexural behavior of simply supported reinforced-concrete (RC) beams flexurally strengthened with prestressed carbon fiber reinforced polymer (CFRP) reinforcements using either externally bonded reinforcing (EBR) or near surface mounted (NSM) techniques. This design methodology also considers the ultimate flexural capacity of NSM CFRP strengthened beams when concrete cover delamination is the governing failure mode. A moment–curvature (M–χ) relationship formed by three linear branches corresponding to the precracking, postcracking, and postyielding stages is established by considering the four critical M–χ points that characterize the flexural behavior of CFRP strengthened beams. Two additional M–χ points, namely, concrete decompression and steel decompression, are also defined to assess the initial effects of the prestress force applied by the FRP reinforcement. The mid-span deflection of the beams is predicted based on the curvature approach, assuming a linear curvature variation between the critical points along the beam length. The good predictive performance of the analytical model is appraised by simulating the force–deflection response registered in experimental programs composed of RC beams strengthened with prestressed NSM CFRP reinforcements.The study reported in this paper is part of the project "PreLami - Performance of reinforced concrete structures strengthened in flexural with an innovative system using prestressed NSM CFRP laminates", with the reference PTDC/ECM/114945/2009. The third author also wishes to acknowledge the scholarship granted by FT (SFRH/BD/61756/2009). The authors would also like to acknowledge the support provided by S&P, for supplying the adhesives and the laminates, and Casais and CiviTest for the preparation of the beams

    Antifungal Activity of Dried Extracts of Anise (Pimpinella anisum L.) and Star anise (Illicium verum Hook. f.) Against Dermatophyte and Saprophyte Fungi

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    Background: Medicinal plants synthesize a vast array of secondary metabolites that are important for human life. For medicinal purpose, antimicrobial activity of substances derived from plant extracts has been recognized for many years. Pimpinella anisum L.(Apiaceae) and Illicium verum Hook. f. (Illiciaceae) plant species, have been used for treatment of infectious diseases in Iranian traditional medicine. Objective: In this study methanol extracts of Pimpinella anisum L. (Apiaceae) and Illicium verum Hook. f. (Illiciaceae), were tested for their potential antifungal activities. Methods: Methanolic extracts were dried by freeze drying method, Minimum Inhibitory Concentration (MIC) was was determined according to agar dilution method and Minimum Fungicidal Concentration (MFC) was determined by incorporating various concentrations of extracts (2-256 mg/ml) in Sabouraud dextrose agar (SDA) in tubes against 4 dermatophyte and one saprophyte fungi. Results: The extracts of anise seeds inhibited only dermatophyte species, while extracts of star anise fruits inhibited growth of all dermatophytes and saprophytes. MIC and MFC for each extracts were different and MFC was higher than MIC for all species. Conclusion: As a result of this experiment, these plants can be candidate for further studies due to their antifungal potencies

    Atypical functional connectivity in adolescents and adults with persistent and remitted ADHD during a cognitive control task

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    Abstract We previously provided initial evidence for cognitive and event-related potential markers of persistence/remission of attention-deficit/hyperactivity disorder (ADHD) from childhood to adolescence and adulthood. Here, using a novel brain-network connectivity approach, we aimed to examine whether task-based functional connectivity reflects a marker of ADHD remission or an enduring deficit unrelated to ADHD outcome. High-density EEG was recorded in a follow-up of 110 adolescents and young adults with childhood ADHD (87 persisters, 23 remitters) and 169 typically developing individuals during an arrow-flanker task, eliciting cognitive control. Functional connectivity was quantified with network-based graph-theory metrics before incongruent (high-conflict) target onset (pre-stimulus), during target processing (post-stimulus) and in the degree of change between pre-stimulus/post-stimulus. ADHD outcome was examined with parent-reported symptoms and impairment using both a categorical (DSM-IV) and a dimensional approach. Graph-theory measures converged in indicating that, compared to controls, ADHD persisters showed increased connectivity in pre-stimulus theta, alpha, and beta and in post-stimulus beta (all p < .01) and reduced pre-stimulus/post-stimulus change in theta connectivity (p < .01). In the majority of indices showing ADHD persister–control differences, ADHD remitters differed from controls (all p < .05) but not from persisters. Similarly, connectivity measures were unrelated to continuous outcome measures of ADHD symptoms and impairment in participants with childhood ADHD. These findings indicate that adolescents and young adults with persistent and remitted ADHD share atypical over-connectivity profiles and reduced ability to modulate connectivity patterns with task demands, compared to controls. Task-based functional connectivity impairments may represent enduring deficits in individuals with childhood ADHD irrespective of diagnostic status in adolescence/young adulthood

    Energy Performance of Advanced Reboiled and Flash Stripper Configurations for CO2 Capture Using Monoethanolamine

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    CO2 capture by absorption using amine solvents has the potential to significantly reduce the CO2 emissions from fossil-fuel power plants. One of the major costs of this technology is the energy required for solvent regeneration. Complex process configurations claim to have promising potential to reduce the energy required for solvent regeneration. In this work, the effect of flow-sheet complexity is explored by studying two advanced stripping flow sheets: an advanced flash stripper and an advanced reboiled stripper. Both advanced configurations recover the stripping steam heat by means of a heat integration comprised of cold- and warm-rich solvent bypasses. The advanced configurations are simulated and optimized in Aspen Plus V.8.4 using 7 m monoethanolamine (MEA) with lean loading from 0.15 to 0.38 (mol CO2/mol MEA). The rich loading associated with each lean loading is determined by simulating the absorber providing 90% capture from flue gas with 4 mol % CO2, typical of a natural gas-fired turbine. The results are compared to a simple stripper in terms of total equivalent work. Both the advanced reboiled stripper and the advanced flash stripper require 12% less equivalent work than a simple stripper. The associated cold-rich and warm-rich bypasses for the optimum cases are, respectively, 20% and 50% for the advanced reboiled stripper and 15% and 35% for the advanced flash stripper

    Genomic instability in human cancer: molecular insights and opportunities for therapeutic attack and prevention through diet and nutrition

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    Genomic instability can initiate cancer, augment progression, and influence the overall prognosis of the affected patient. Genomic instability arises from many different pathways, such as telomere damage, centrosome amplification, epigenetic modifications, and DNA damage from endogenous and exogenous sources, and can be perpetuating, or limiting, through the induction of mutations or aneuploidy, both enabling and catastrophic. Many cancer treatments induce DNA damage to impair cell division on a global scale but it is accepted that personalized treatments, those that are tailored to the particular patient and type of cancer, must also be developed. In this review, we detail the mechanisms from which genomic instability arises and can lead to cancer, as well as treatments and measures that prevent genomic instability or take advantage of the cellular defects caused by genomic instability. In particular, we identify and discuss five priority targets against genomic instability: (1) prevention of DNA damage; (2) enhancement of DNA repair; (3) targeting deficient DNA repair; (4) impairing centrosome clustering; and, (5) inhibition of telomerase activity. Moreover, we highlight vitamin D and B, selenium, carotenoids, PARP inhibitors, resveratrol, and isothiocyanates as priority approaches against genomic instability. The prioritized target sites and approaches were cross validated to identify potential synergistic effects on a number of important areas of cancer biology

    Homozygous Missense Variants in NTNG2, Encoding a Presynaptic Netrin-G2 Adhesion Protein, Lead to a Distinct Neurodevelopmental Disorder.

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    NTNG2 encodes netrin-G2, a membrane-anchored protein implicated in the molecular organization of neuronal circuitry and synaptic organization and diversification in vertebrates. In this study, through a combination of exome sequencing and autozygosity mapping, we have identified 16 individuals (from seven unrelated families) with ultra-rare homozygous missense variants in NTNG2; these individuals present with shared features of a neurodevelopmental disorder consisting of global developmental delay, severe to profound intellectual disability, muscle weakness and abnormal tone, autistic features, behavioral abnormalities, and variable dysmorphisms. The variants disrupt highly conserved residues across the protein. Functional experiments, including in silico analysis of the protein structure, in vitro assessment of cell surface expression, and in vitro knockdown, revealed potential mechanisms of pathogenicity of the variants, including loss of protein function and decreased neurite outgrowth. Our data indicate that appropriate expression of NTNG2 plays an important role in neurotypical development
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