746 research outputs found

    Simultaneous Multiple Surface Segmentation Using Deep Learning

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    The task of automatically segmenting 3-D surfaces representing boundaries of objects is important for quantitative analysis of volumetric images, and plays a vital role in biomedical image analysis. Recently, graph-based methods with a global optimization property have been developed and optimized for various medical imaging applications. Despite their widespread use, these require human experts to design transformations, image features, surface smoothness priors, and re-design for a different tissue, organ or imaging modality. Here, we propose a Deep Learning based approach for segmentation of the surfaces in volumetric medical images, by learning the essential features and transformations from training data, without any human expert intervention. We employ a regional approach to learn the local surface profiles. The proposed approach was evaluated on simultaneous intraretinal layer segmentation of optical coherence tomography (OCT) images of normal retinas and retinas affected by age related macular degeneration (AMD). The proposed approach was validated on 40 retina OCT volumes including 20 normal and 20 AMD subjects. The experiments showed statistically significant improvement in accuracy for our approach compared to state-of-the-art graph based optimal surface segmentation with convex priors (G-OSC). A single Convolution Neural Network (CNN) was used to learn the surfaces for both normal and diseased images. The mean unsigned surface positioning errors obtained by G-OSC method 2.31 voxels (95% CI 2.02-2.60 voxels) was improved to 1.271.27 voxels (95% CI 1.14-1.40 voxels) using our new approach. On average, our approach takes 94.34 s, requiring 95.35 MB memory, which is much faster than the 2837.46 s and 6.87 GB memory required by the G-OSC method on the same computer system.Comment: 8 page

    Low Q2Q^2 proton structure function, using gluon and pseudoscalar meson clouds in the constituent quark framework

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    The idea of the meson cloud approach in the chiral quark model has been extended to include gluon cloud in order to achieve the parton densities in the nucleon, based on the constitute quark framework. The splitting function of the quark to the quark-meson and quark-gluon at low Q2Q^2 value are used to obtain parton densities in the constituent quark. The phenomenological constituent model is employed to extract the parton distributions in the proton at low Q2Q^2 value. Since we have access to the parton densities at low Q2Q^2, we are able to obtain F2(x,Q2)F_{2}(x,Q^2) structure function at low Q2Q^2 value. The result is in good agreement with available experimental data and some theoretical models. To confirm the validity of our calculations, the fraction of total momentum of proton which is carried by gluon at high Q2Q^2 and also the Gottfried sum rule are computed. The results are in good agreement with what are expected.Comment: 13 pages, 3 figure

    Cadmium induced oxidative stress in Dunaliella salina

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    The unicellular green algae Dunaliella salina contains various antioxidants which protect the cell from oxidative damage due to environmental stresses such as heavy metal stress. In the present study, the response of D. salina at the stationary growth phase to oxidative stress generated by cadmium chloride was investigated. Growth, expressed as cell number per ml of culture, did not change up to 75 μM cadmium but decreased significantly at 100 and 150 μM Cd2+. Reduction in chlorophyll content and carotenoids content per ml of culture was observed in the presence of Cd2+. Total antioxidant activity, expressed as μmole Trolox equivalent per 106 cell (μmol TE 106 cell-1) and also total phenolic content (pg GAE, cell-1) were significantly reduced in the presence of Cd2+. Lower Cd2+ concentration had no influence on the activity of ascorbate peroxidase, 100 and 150 μM Cd2+ caused significant reduction in enzyme activity. Lipid peroxidation, reported as malondialdehyde content, was the same as control up to 100 μM Cd2+ but increased at higher Cd2+ concentration. It is concluded that high concentration of cadmium have negative effect on aquatic algae.Keywords: Dunaliella salina, Carotenoids, Antioxidant activity, Cadmium chloride, Lipidperoxidation, Ascorbate peroxidas

    Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and the Truncated Moments

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    Since there are not experimental data over the whole range of x-Bjorken variable, that is, 0<x<1, we are inevitable in practice to do the integration for Mellin moments over the available range of experimental data. Among the methods of analysing DIS data, there are the methods based on application of Mellin moments. We use the truncated Mellin moments rather than the usual moments to analyse the EMC collaboration data for muon-nucleon and WA25 data for neutrino-deuterium DIS scattering. How to connect the truncated Mellin moments to usual ones is discussed. Following that we combine the truncated Mellin moments with the Bernstein polynomials. As a result, Bernstein averages which are related to different orders of the truncated Mellin moment are obtained. These averaged quantities can be considered as the constructed experimental data. By accessing the sufficient experimental data we can do the fitting more precisely. We do the fitting at leading order and next-to-leading order approximations to extract the QCD cutoff parameter. The results are in good agreement with what is being expected

    CLC, a promising concept with challenging development issues

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    Chemical Looping Combustion (CLC) is a promising technique to achieve fuel combustion in a nitrogen free atmosphere, therefore giving the possibility to separate and store or use CO2. Several potential applications are considered in the field of power generation with gas, liquid and solid fuels. In the Carbon Capture, Storage and Utilization (CCSU) context, energy penalty is reduced compared to other routes. In addition, other applications of Chemical Looping are considered in the field of H2 production or gasification for instance. In the past years, a huge effort has been conducted worldwide to investigate CLC materials and process issues. In 2008, IFPEN and Total have started an ambitious collaboration to develop CLC applications. Nowadays, the CLC concept is well demonstrated at the pilot scale. The next step is to demonstrate the technology over time at larger scale. However, for further developments, the challenges are numerous and will be discussed, both on market and technical aspects. Short term market is limited. Uncertainties around CO2 emission market and storage issues are related to CO2 policy and public acceptance of storage which still must evolve in the right direction... Financing of demonstration units in this context is challenging and other applications of CLC have to be investigated. The industrial use of synthetic metal oxides or natural ores at large scale generates a lot of issues related to availability, price, waste disposal, health and safety, additionally to chemical and mechanical stability over time, reactivity, and oxygen transfer capacity. Chemical looping reactor and process technology concepts have to be explored, developed, modeled and scaled-up in order to ensure adequate power production together with good gas solid contact and reaction requirement, controlled circulation of mixtures of particle (oxygen carrier, ash, solid fuel for instance). All these points should be considered at very large scale for CCS applications in order to minimize energy penalty and cost in severe operating conditions (temperatures above 800°C and intense solid circulation). Technical challenges remain to be solved and proven with large demonstration over long periods of time. In this context, research in the field of fluidization technology is essential and we will address a couple of key points already investigated at IFPEN and related to control of solid circulation, oxygen carrier attrition, conceptual design of CLC reactors and process performance

    Evaluation inhibitory effect of essential oil Savory (Satureja hortensis) in food fish

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    Aflatoxins are a group of fungal metabolites that are produced by the growth of fungi on food. These toxins cause illness in animals and humans, and are important in economic and humans health. In this investigation, inhibitory effects of savory (Satureja hortensis L.) essential oil were evaluated on the growth of Aspergillus flavus in fish food. A gas chromatograph apparatus linked to a mass spectrometer (GC/MS) was used to identify the effective components in Satureja hortensis essential oil after extraction. Essential oils against Aspergillus flavus incubated in PDA media and antifungal properties of essential oil Satureja hortensis was investigated. About of 300g of food samples was weighted and samples were sterilized by autoclave. Fungal suspension (3cc) was spraied into the feed samples, and various concentrations of essential oils (0, 300, 400, 500, 600ppm) added to samples. The samples were incubated at temperature of (±SD) 28±2°C. After 20-40 and 60 days period, randomly, some sampled were taken from containers and the production of aflatoxin B1, B2, G1, and G2 was measured in the laboratory. This result confirms that 500ppm concentrations of oil savory have antifungal properties against Aspergillus flavus
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