1,464 research outputs found

    Amphiphilic diblock copolymers as functional surfaces for protein chromatography

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    Stationary phase plays a crucial role in the operation of a protein chromatography column. Conventional resins composed of acrylic polymers and their derivatives contribute to heterogeneity of the packing of stationary phase inside these columns. Alternative polymer combinations through customized surface functionalization schemes which consist of multiple steps using static coating techniques are well known. In comparison, it is hypothesized that a single-step scheme is sufficient to obtain porous adsorbents as stationary phase for tuning surface morphology and protein immobilization. To overcome the challenge of heterogeneous packing and ease of fabrication at a laboratory scale, a change in the form factor of separation materials has been proposed in the form of functional copolymer surfaces. In the present work, an amphiphilic, block copolymer, poly(methyl methacrylate-co-methacrylic acid) has been chosen and fully characterized for its potential usage in protein chromatography. Hydrophilicity of the acrylic copolymer and abundance of carboxyl groups inherently on the copolymer surface have been successfully demonstrated through contact angle measurements, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) studies. Morphological studies indicate presence of a microporous region (nearly 1 to 1.5 μ\mum pore size) that could be beneficial as a cation exchange media as part of the stationary phase in protein chromatography.Comment: 10 figures, submitted to Journa

    Improved supervised learning-based approach for leaf and wood classification from LiDAR point clouds of forests

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    Accurately classifying 3-D point clouds into woody and leafy components has been an interest for applications in forestry and ecology including the better understanding of radiation transfer between canopy and atmosphere. The past decade has seen an increase in the methods attempting to classify leaves and wood in point clouds based on radiometric or geometric features. However, classification purely based on radiometric features is sensor-specific, and the method by which the local neighborhood of a point is defined affects the accuracy of classification based on geometric features. Here, we present a leaf-wood classification method combining geometrical features defined by radially bounded nearest neighbors at multiple spatial scales in a machine learning model. We compared the performance of three different machine learning models generated by the random forest (RF), XGBoost, and lightGBM algorithms. Using multiple spatial scales eliminates the need for an optimal neighborhood size selection and defining the local neighborhood by radially bounded nearest neighbors makes the method broadly applicable for point clouds of varying quality. We assessed the model performance at the individual tree- and plot-level on field data from tropical and deciduous forests, as well as on simulated point clouds. The method has an overall average accuracy of 94.2% on our data sets. For other data sets, the presented method outperformed the methods in literature in most cases without the need for additional postprocessing steps that are needed in most of the existing methods. We provide the entire framework as an open-source python package

    Hoe lawaaierig is de oceaan?

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    Onder de zeespiegel is het nooit stil. De mens – wat dacht je – drukt er zijn stempel. Al gaat de natuur niet vrijuit. En het geluid zit werkelijk overal. Zelfs in de Marianentrog, met 11 km het diepste punt van de wereldzeeën, is geluid alomtegenwoordig. Aardbevingen, walvissen, schepen en orkanen creëren er een kakafonie van geluiden. In wat volgt gaan we op zoek naar het voorkomen en de invloed van onderwatergeluiden in de oceaan. We zoeken een antwoord op de vraag: hoe natuurlijk is het geluid in de oceaan, wat betekent dit voor zeedieren en wat kunnen we doen om extra geluidvervuiling te voorkomen of te milderen

    Comorbidities and Treatments in United States Youth with Chronic Musculoskeletal Pain

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    Introduction: Chronic musculoskeletal (MSK) pain has been associated with chronic illnesses and high rates of pain medication use, often in referral centers, European populations, or studies focused on single drug classes. We aimed to characterize patterns of comorbidities and treatments associated with chronic MSK pain in a nationally-representative sample of US youth. Methods: We used the National Ambulatory Medical Care Survey (2002-2015) and National Hospital Ambulatory Medical Care Survey (2002-2011), which contain cross-sectional data for US outpatient visits. The study included all visits for youth age 8-24, excluding those with malignancy or sickle cell disease. We compared comorbidities and drugs ordered in visits for chronic MSK pain with (1) visits for any reason besides MSK pain and (2) visits for acute MSK pain, using chi-square tests and logistic regression, adjusting for several covariates. Results: Chronic non-psychiatric diseases were more common among visits for chronic MSK pain (32.0%) in comparison to both visits for acute MSK pain (17.9%) and visits for other reasons (18.8%). Nonsteroidal anti-inflammatories were less commonly ordered at visits for chronic MSK pain in comparison to acute MSK pain (adjusted odds ratio [aOR]: 0.63, 95% CI 0.50-0.80). Opioids, gabapentinoids, and alternative medicine were each ordered more commonly at visits for chronic MSK pain in comparison to visits for acute MSK pain and other visits. Conclusion: US youth with chronic MSK were more likely to have chronic non-psychiatric medical conditions compared to youth without pain. Additionally, opioids, gabapentinoids, and alternative medicine were ordered more often in chronic MSK visits, which warrants further study

    Integrated campaign for aerosols, gases and radiation budget (ICARB): an overview

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    During March-May 2006, an extensive, multi-institution, multi-instrument, and multi-platform integrated field experiment 'Integrated Campaign for Aerosols, gases and Radiation Budget' (ICARB) was carried out under the Geosphere Biosphere Programme of the Indian Space Research Organization (ISRO-GBP). The objective of this largest and most exhaustive field campaign, ever conducted in the Indian region, was to characterize the physico-chemical properties and radiative effects of atmospheric aerosols and trace gases over the Indian landmass and the adjoining oceanic regions of the Arabian Sea, northern Indian Ocean, and Bay of Bengal through intensive, simultaneous observations. A network of ground-based observatories (over the mainland and islands), a dedicated ship cruise over the oceanic regions using a fully equipped research vessel, the Sagar Kanya, and altitude profiling over selected regions using an instrumented aircraft and balloonsondes formed the three segments of this integrated experiment, which were carried out in tandem. This paper presents an overview of the ICARB field experiment, the database generated, and some of its interesting outcomes though these are preliminary in nature. The ICARB has revealed significant spatio-temporal heterogeneity in most of the aerosol characteristics both over land and ocean. Observed aerosol loading and optical depths were comparable to or in certain regions, a little lower than those reported in some of the earlier campaigns for these regions. The preliminary results indicate: - low (< 0.2) aerosol optical depths (AOD) over most part of the Arabian Sea, except two pockets; one off Mangalore and the other, less intense, in the central Arabian Sea at ~18°N latitude - High Angstrom exponent in the southern Arabian Sea signifying steep AOD spectra and higher abundance of accumulation mode particles in the southern Arabian Sea and off Mangalore - Remarkably low Angstrom exponents signifying increased concentration of coarse mode aerosols and high columnar abundance in the northern Arabian Sea - Altitude profiles from aircraft showed a steady BC level up to 3 km altitude with structures which were associated with inversions in the atmospheric boundary layer (ABL) - A surprisingly large increase in the BC mass fraction with altitude - Presence of a convectively mixed layer extending up to about 1 km over the Arabian Sea and Bay of Bengal - A spatial off shore extent of < 100 km for the anthropogenic impact at the coast; and - Advection of aerosols, through airmass trajectories, from west Asia and NW arid regions of India leading to formation of elevated aerosol layers extending as far as 400 km off the east coast

    Using Citizen Science to Help Monitor Urban Landscape Changes and Drive Improvements

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    Citizen Science has become a vital source for data collection when the spatial and temporal extent of a project makes it too expensive to send experts into the field. However, involving citizens can go further than that – participatory projects focusing on subjective parameters can fill in the gap between local community needs and stakeholder approaches to tackle key social and environmental issues. LandSense, a Horizon 2020 project that is deeply rooted in environmental challenges and solutions, aims to establish a citizen observatory that will provide data to stakeholders, from researchers to businesses. Within this project, a mobile application has been developed that aims not only to stimulate civic engagement to monitor changes within the urban environment, but also to enable users to drive improvements by providing city planners with information about the public perception of urban spaces. The launch of a public version of such an app requires preparation and testing by focus groups. Recently, a prototype of the app was used by both staff and students from Vienna University of Technology, who contributed valuable insights to help enhance this citizen science tool for engaging and empowering the inhabitants of the city

    Effect of Variable Viscosity on Convective Heat and Mass Transfer by Natural Convection from Vertical Surface in Porous Medium

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    Abstract: -The aim of this paper is to investigate the effect of variable viscosity on free convective heat and mass transfer from a vertical plate embedded in a saturated porous medium. The governing equations of continuity, momentum, energy and concentration are transformed into non linear ordinary differential equations using similarity transformations and then solved by using Runge -Kutta -Gill method along with shooting technique. Governing parameters for the problem under study are the variable viscosity, the buoyancy ratio and the Lewis number. The velocity, temperature and concentration distributions are presented and discussed. The Nusselt and Sherwood number are also derived. The numerical values of local Nusselt and local Sherwood numbers have also been computed for a wide range of governing parameters. The viscous and thermal boundary layer thicknesses are discusse

    Effects of Variable Viscosity on Power-Law Fluids over a Permeable Moving Surface with Slip Velocity in the Presence of Heat Generation and Suction

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    In this paper, a numerical investigation on the effects of variable viscosity, slip velocity and heat generation or absorption on power-law fluids with heat and mass transfer over a moving permeable surface is carried out. The transformation of the governing boundary layer equations into ordinary differential equations has been performed by applying similarity transformations. The transformed governing equations are numerically solved by using MATLAB BVP solver bvp4c. The obtained results are presented graphically and discussed for various values of the viscosity parameter, the slip parameter, the heat generation or absorption parameter, the Eckert number and Lewis number. The result shows that, the variable viscosity parameter , it is confirmed that the local skin-friction coefficient decreases while heat and mass transfer rates increases. The heat and mass transfer rates increases rapidly on increasing the Prandtl number. The rate of mass transfer is rapidly increased when the Lewis number increased

    Case Report of Fibrodysplasia Ossificans Progressiva

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    Fibrodysplasia ossificans progressiva is a rare genetic disease characterized by widespread soft tissue ossification and congenital stigmata of the extremities. We report a male patient who had bilateral hallux valgus since birth. Other noticed anomalies included multiple swellings over the back, stiffness of lower back area, multiple joints, restricting movement of spine, shoulders, elbows, and right hip and right knee. Patient was not able to bend forward, squat or turn head to either side. Patient also had multiple foci of ossification developed over left knee, and back region. All swellings and restrictions were painless
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