1,893 research outputs found

    A WEARABLE FOOT MOTION TRACKING SENSOR FOR OUTDOOR RUNNING

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    Throughout human history, running has evolved from a form of locomotion to a recreation or competitive pursuit. The purpose of this project was to develop a foot motion tracking sensor using inertial measurement unit (IMU) to determine the running kinematics of the ankles of individuals under different external or physical conditions such as change in directions, running on slopes or level ground or fatigue. These results may be helpful in providing a real-time quantitative data, which will be useful for runners to monitor their training programs and routes. The preliminary results showed that the system can detect ankle dorsiflexion/plantarflexion across different route condition, where these results can be used for further analysis such as designing a training program and monitoring the fatigue level

    A finite strain nonlinear human mitral valve model with fluid structure interaction

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    A simulated human mitral valve under a physiological pressure loading is developed using a hybrid finite element immersed boundary method, which incorporates experimentally based constitutive laws in a three-dimensional fluid-structure interaction framework. A transversely isotropic material constitutive model is used for characterizing the mechanical behaviour of the mitral valve tissue based on recent mechanical tests of healthy human mitral leaflets. Our results show good agreement, in terms of the flow rate and the closing and opening configurations, with the measurements from the magnetic resonance images. The stresses in the anterior leaflet are found to be higher than those in the posterior leaflet, and concentrated around the annulus trigons and free edges of the valve leaflets. Those areas are located where the leaflet has the highest curvature. Effects of the chordae tendineae in the material model are studied and the results show that these chordae play an important role in providing a secondary orifice for the flow when valve opens. Although there are some discrepancies to be overcome in future works, our simulations show that the developed computational model is promising in mimicking the in vivo mitral valve dynamics and providing important information that are not obtainable by in vivo measurements. This article is protected by copyright. All rights reserved

    Fluorescent nanoparticles for sensing

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    Nanoparticle-based fluorescent sensors have emerged as a competitive alternative to small molecule sensors, due to their excellent fluorescence-based sensing capabilities. The tailorability of design, architecture, and photophysical properties has attracted the attention of many research groups, resulting in numerous reports related to novel nanosensors applied in sensing a vast variety of biological analytes. Although semiconducting quantum dots have been the best-known representative of fluorescent nanoparticles for a long time, the increasing popularity of new classes of organic nanoparticle-based sensors, such as carbon dots and polymeric nanoparticles, is due to their biocompatibility, ease of synthesis, and biofunctionalization capabilities. For instance, fluorescent gold and silver nanoclusters have emerged as a less cytotoxic replacement for semiconducting quantum dot sensors. This chapter provides an overview of recent developments in nanoparticle-based sensors for chemical and biological sensing and includes a discussion on unique properties of nanoparticles of different composition, along with their basic mechanism of fluorescence, route of synthesis, and their advantages and limitations

    Fabrication, Modeling and Characterization of Multi-Crosslinked Methacrylate Copolymeric Nanoparticles for Oral Drug Delivery

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    Nanotechnology remains the field to explore in the quest to enhance therapeutic efficacies of existing drugs. Fabrication of a methacrylate copolymer-lipid nanoparticulate (MCN) system was explored in this study for oral drug delivery of levodopa. The nanoparticles were fabricated employing multicrosslinking technology and characterized for particle size, zeta potential, morphology, structural modification, drug entrapment efficiency and in vitro drug release. Chemometric Computational (CC) modeling was conducted to deduce the mechanism of nanoparticle synthesis as well as to corroborate the experimental findings. The CC modeling deduced that the nanoparticles synthesis may have followed the mixed triangular formations or the mixed patterns. They were found to be hollow nanocapsules with a size ranging from 152 nm (methacrylate copolymer) to 321 nm (methacrylate copolymer blend) and a zeta potential range of 15.8–43.3 mV. The nanoparticles were directly compressible and it was found that the desired rate of drug release could be achieved by formulating the nanoparticles as a nanosuspension, and then directly compressing them into tablet matrices or incorporating the nanoparticles directly into polymer tablet matrices. However, sustained release of MCNs was achieved only when it was incorporated into a polymer matrix. The experimental results were well corroborated by the CC modeling. The developed technology may be potentially useful for the fabrication of multi-crosslinked polymer blend nanoparticles for oral drug delivery

    Graphene in Lithium-Ion/Lithium-Sulfur Batteries

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    In order to deal with the energy demand of the increasing global population,the use of sustainable sources of energy has become mandatory to attenuate theenvironmental problems that come along with the use of fossil sources of energy.However, one of the problems of renewable energy sources, such as wind or sun,is that they are intermittent. So, in order to make the best use of them, we needgood energy storage systems able to capture, manage and store energy at a largescale and low cost. If we are also capable of replacing the gasoline powered transportationwith electric vehicles, the greenhouse emissions would be significantlyreduced. As well, it is necessary a change in the energetic matrix for stationarydevices to solve the transport cost and the greenhouse emission provokes for theuse of natural gas. Considering this, the major promises to accomplish the needsof high gravimetric, volumetric and power density is given by lithium batteries.In the past decades and up to nowadays, they have become the energy source ofalmost all electronic portable devices and made possible a huge number of technologicalapplications. Graphene based materials, due to their unique properties,have become of great interest to be used in different components of the battery:anode, cathode and separator. As part of the electrodes, used adequately, graphenematerials improve the electron and ionic mobility providing not only higher electricalconductivity, but also higher capacity. Due to the rich carbon chemistry,graphene can be easily functionalized with different groups leading to changes inits properties. In this sense, the nano-sized dimension and elevated specific surfacearea makes it a perfect candidate for improving conductivity, connectivity andlithium-ion transport in both cathode and anode active materials. Functionalizedgraphene is also used in the modification of separators of lithium-sulfur batteriesfor the suppression of the polysulfide shuttle mechanism due to its interaction/repulsion with the charged intermediate polysulfide species. This chapter presentsa critical overview of the state-of-art in the optimization and application ofgraphene derived materials for anodes, cathodes and separators in lithium batteries.Besides a thorough description of novel designs and general discussion of theattained electrochemical performances, this chapter also aims to discuss desiredproperties and current drawbacks for massive industrial application in lithiumbatteries.Fil: Luque, Guillermina Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Para, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Primo, Emiliano Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Calderón, Andrea Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Bracamonte, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Otero, Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Rojas, María del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: García Soriano, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Lener, German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

    (Photo-)crosslinkable gelatin derivatives for biofabrication applications

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    Over the recent decades gelatin has proven to be very suitable as an extracellular matrix mimic for bio-fabrication and tissue engineering applications. However, gelatin is prone to dissolution at typical cell culture conditions and is therefore often chemically modified to introduce (photo-)crosslinkable functionalities. These modifications allow to tune the material properties of gelatin, making it suitable for a wide range of biofabrication techniques both as a bioink and as a biomaterial ink (component). The present review provides a non-exhaustive overview of the different reported gelatin modification strategies to yield crosslinkable materials that can be used to form hydrogels suitable for biofabrication applications. The different crosslinking chemistries are discussed and classified according to their mechanism including chain-growth and step-growth polymerization. The step-growth polymerization mechanisms are further classified based on the specific chemistry including different (photo-)click chemistries and reversible systems. The benefits and drawbacks of each chemistry are also briefly discussed. Furthermore, focus is placed on different biofabrication strategies using either inkjet, deposition or light-based additive manufacturing techniques, and the applications of the obtained 3D constructs

    Genetic Variants on Chromosome 1q41 Influence Ocular Axial Length and High Myopia

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    As one of the leading causes of visual impairment and blindness, myopia poses a significant public health burden in Asia. The primary determinant of myopia is an elongated ocular axial length (AL). Here we report a meta-analysis of three genome-wide association studies on AL conducted in 1,860 Chinese adults, 929 Chinese children, and 2,155 Malay adults. We identified a genetic locus on chromosome 1q41 harboring the zinc-finger 11B pseudogene ZC3H11B showing genome-wide significant association with AL variation (rs4373767, β = −0.16 mm per minor allele, Pmeta = 2.69×10−10). The minor C allele of rs4373767 was also observed to significantly associate with decreased susceptibility to high myopia (per-allele odds ratio (OR) = 0.75, 95% CI: 0.68–0.84, Pmeta = 4.38×10−7) in 1,118 highly myopic cases and 5,433 controls. ZC3H11B and two neighboring genes SLC30A10 and LYPLAL1 were expressed in the human neural retina, retinal pigment epithelium, and sclera. In an experimental myopia mouse model, we observed significant alterations to gene and protein expression in the retina and sclera of the unilateral induced myopic eyes for the murine genes ZC3H11A, SLC30A10, and LYPLAL1. This supports the likely role of genetic variants at chromosome 1q41 in influencing AL variation and high myopia

    Association analyses of East Asian individuals and trans-ancestry analyses with European individuals reveal new loci associated with cholesterol and triglyceride levels

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    Large-scale meta-analyses of genome-wide association studies (GWAS) have identified >175 loci associated with fasting cholesterol levels, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). With differences in linkage disequilibrium (LD) structure and allele frequencies between ancestry groups, studies in additional large samples may detect new associations. We conducted staged GWAS meta-analyses in up to 69,414 East Asian individuals from 24 studies with participants from Japan, the Philippines, Korea, China, Singapore, and Taiwan. These meta-analyses identified (P < 5 × 10-8) three novel loci associated with HDL-C near CD163-APOBEC1 (P = 7.4 × 10-9), NCOA2 (P = 1.6 × 10-8), and NID2-PTGDR (P = 4.2 × 10-8), and one novel locus associated with TG near WDR11-FGFR2 (P = 2.7 × 10-10). Conditional analyses identified a second signal near CD163-APOBEC1. We then combined results from the East Asian meta-analysis with association results from up to 187,365 European individuals from the Global Lipids Genetics Consortium in a trans-ancestry meta-analysis. This analysis identified (log10Bayes Factor ≥6.1) eight additional novel lipid loci. Among the twelve total loci identified, the index variants at eight loci have demonstrated at least nominal significance with other metabolic traits in prior studies, and two loci exhibited coincident eQTLs (P < 1 × 10-5) in subcutaneous adipose tissue for BPTF and PDGFC. Taken together, these analyses identified multiple novel lipid loci, providing new potential therapeutic targets
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