925 research outputs found

    INFLUENCE OF CONCENTRATION IN THE ELEVATION OF BOILING POINT OF MANGO PULP (Mangifera indica L.)

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    The objective of this study was to determine the elevation in boiling point of mango pulp was measured at soluble solids concentrations between range 13 and 55°Brix and pressures in the range 9.820x103 to 1.009 x 105 Pa (abs.). The pulp was processed in a pulper with a 1.5mm screen to obtain a uniform consistency and concentrated in rotating evaporator. 500 mL sample of mango pulp was introduced into the boiling vessel. Temperature and pressure were continuously recorded, and final values for solution boiling point and associated pressure were registered after readings had been constant for at least 5 minutes. Experimental data are represented using the Duhring’s rule, Antoine equation and empirical model Crapiste and Lozano. The elevation in boiling point was nearly independent of pressure, varying only with pulp concentration. Experimental data were adjusted appropriately to Antoine equation (R2>0.98) and Crapiste and Lozano model (R2>0.88)

    Identification of Light Sources using Machine Learning

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    The identification of light sources represents a task of utmost importance for the development of multiple photonic technologies. Over the last decades, the identification of light sources as diverse as sunlight, laser radiation and molecule fluorescence has relied on the collection of photon statistics or the implementation of quantum state tomography. In general, this task requires an extensive number of measurements to unveil the characteristic statistical fluctuations and correlation properties of light, particularly in the low-photon flux regime. In this article, we exploit the self-learning features of artificial neural networks and naive Bayes classifier to dramatically reduce the number of measurements required to discriminate thermal light from coherent light at the single-photon level. We demonstrate robust light identification with tens of measurements at mean photon numbers below one. Our work demonstrates an improvement in terms of the number of measurements of several orders of magnitude with respect to conventional schemes for characterization of light sources. Our work has important implications for multiple photonic technologies such as LIDAR and microscopy.Comment: 8 pages, 10 figure

    Exceptional points of any order in a single, lossy waveguide beam splitter by photon-number-resolved detection

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    Exceptional points (EPs) are degeneracies of non-Hermitian operators where, in addition to the eigenvalues, the corresponding eigenmodes become degenerate. Classical and quantum photonic systems with EPs have attracted tremendous attention due to their unusual properties, topological features, and an enhanced sensitivity that depends on the order of the EP, i.e., the number of degenerate eigenmodes. Yet, experimentally engineering higher-order EPs in classical or quantum domains remain an open challenge due to the stringent symmetry constraints that are required for the coalescence of multiple eigenmodes. Here, we analytically show that the number-resolved dynamics of a single, lossy waveguide beam splitter, excited by indistinguishable photons and post-selected to the -photon subspace, will exhibit an EP of order +1. By using the well-established mapping between a beam splitter Hamiltonian and the perfect state transfer model in the photon-number space, we analytically obtain the time evolution of a general -photon state and numerically simulate the system’s evolution in the post-selected manifold. Our results pave the way toward realizing robust, arbitrary-order EPs on demand in a single device

    Assessment of the toll-like receptor 4 Asp299Gly, Thr399Ile and interleukin-8 -251 polymorphisms in the risk for the development of distal gastric cancer

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    <p>Abstract</p> <p>Background</p> <p>The intensity of the inflammation induced by <it>Helicobacter pylori </it>colonization is associated with the development of distal gastric cancer (GC). The host response to <it>H</it>. <it>pylori </it>has been related to genetic polymorphisms that influence both innate and adaptive immune responses.</p> <p>Our aim was to investigate whether the presence of the <it>TLR4 Asp299Gly</it>, <it>TLR4 Thr399Ile </it>and <it>IL-8-251 </it>A/T polymorphisms had any influence in the development of distal GC in a Mexican population.</p> <p>Methods</p> <p>We studied 337 patients that were divided in two groups: 78 patients with histologically confirmed distal GC and 259 non-cancer controls. The presence of <it>H. pylori </it>in the control population was defined by positive results of at least two of four diagnostic tests: serology, histology, rapid urease test and culture. Human DNA was purified and genotyped for <it>TLR4 Asp299Gly </it>polymorphism by pyrosequencing, for <it>TLR4 Thr399Ile </it>by PCR-RFLP and for <it>IL8-251 </it>by the amplification refractory mutation system (ARMS)-PCR.</p> <p>Results</p> <p>The non-cancer control group was found to be in Hardy-Weinberg equilibrium at the polymorphic loci studied (chi-square <sub>H-W </sub>= 0.58 for <it>IL8-251</it>, 0.42 for <it>TLR4 Asp299Gly </it>and 0.17 for <it>TLR4 Thr399Ile</it>). The frequencies of mutated alleles (homozygous plus heterozygous) were compared between cases and controls. We found no significant difference for <it>TLR4- Asp299Gly </it>[the 7.7% of distal GC patients and 7.7 % non-cancer controls (p = 0.82)] and for <it>TLR4 Thr399Ile </it>[the 1.3% of GC patients and the 5% of the control population (p = 0.2)]. In contrast, for <it>IL-8-251 </it>A/T, 80.77% of the GC patients and 66.4% in the control group age and gender matched had at least one copy of mutated allele (OR = 2.12, 95% CI = 1.1–4.2) (p = 0.023).</p> <p>Conclusion</p> <p>This study showed that the <it>IL8-251*A </it>allele could be related to the development of distal gastric cancer in this Mexican population.</p

    Low-energy effects in brane worlds: Liennard-Wiechert potentials and Hydrogen Lamb shift

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    Testing extra dimensions at low-energies may lead to interesting effects. In this work a test point charge is taken to move uniformly in the 3-dimensional subspace of a (3+nn)-brane embedded in a (3+nn+1)-space with nn compact and one warped infinite spatial extra dimensions. We found that the electromagnetic potentials of the point charge match standard Liennard-Wiechert's at large distances but differ from them close to it. These are finite at the position of the charge and produce finite self-energies. We also studied a localized Hydrogen atom and take the deviation from the standard Coulomb potential as a perturbation. This produces a Lamb shift that is compared with known experimental data to set bounds for the parameter of the model. This work provides details and extends results reported in a previous Letter.Comment: Manuscript (LaTeX) and 2 figure files (eps format) used by the manuscript LaTeX fil

    Casimir effect in a six-dimensional vortex scenario

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    Recently Randjbar-Daemi and Shaposhnikov put forward a 4-dimensional effective QED coming from a Nielsen-Olesen vortex solution of the abelian Higgs model with fermions coupled to gravity in D=6. However, exploring possible physical consequences of such an effective QED was left open. In this letter we study the corresponding effective Casimir effect. We find that the extra dimensions yield fifth and third inverse powers in the separation between plates for the modified Casimir force which are in conflict with known experiments, thus reducing the phenomenological viability of the model.Comment: 12 pages, references added, comparison with experimental data clarified. v4 published versio

    Caracterización del Desbalance en Redes de Distribución Eléctricas Argentinas, a través del Factor de Desbalance Contemplando la Reglamentación Vigente

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    El objeto del presente trabajo es mostrar cuales son los márgenes de desbalance que aparecen y/o podrían aparecer en el sistema de distribución de la Argentina, sin violar la reglamentación nacional vigente al respecto, para compararlos con los recomendados por la normativa internacional vinculada con el tema. En tal sentido se determina el máximo valor posible que podría alcanzar la relación porcentual entre la componente de secuencia negativa y positiva (relación empleada por IEC e IEEE para evaluar el desbalance), utilizando como herramienta un algoritmo genético diseñado específicamente para cumplir con lo propuesto. Además se muestran una serie de mediciones de desbalance, obtenidas en distintos puntos del sistema de distribución eléctrica de baja tensión

    Accelerated directed evolution of dye-decolorizing peroxidase using a bacterial extracellular protein secretion system (BENNY)

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    Background Dye-decolorizing peroxidases (DyPs) are haem-containing peroxidases that show great promises in industrial biocatalysis and lignocellulosic degradation. Through the use of Escherichia coli osmotically-inducible protein Y (OsmY) as a bacterial extracellular protein secretion system (BENNY), we successfully developed a streamlined directed evolution workflow to accelerate the protein engineering of DyP4 from Pleurotus ostreatus strain PC15. Result After 3 rounds of random mutagenesis with error-prone polymerase chain reaction (epPCR) and 1 round of saturation mutagenesis, we obtained 4D4 variant (I56V, K109R, N227S and N312S) that displays multiple desirable phenotypes, including higher protein yield and secretion, higher specific activity (2.7-fold improvement in kcat/Km) and higher H2O2 tolerance (sevenfold improvement based on IC50). Conclusion To our best knowledge, this is the first report of applying OsmY to simplify the directed evolution workflow and to direct the extracellular secretion of a haem protein such as DyP4
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