1,288 research outputs found

    Kolmogorov-Sinai entropy from recurrence times

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    Observing how long a dynamical system takes to return to some state is one of the most simple ways to model and quantify its dynamics from data series. This work proposes two formulas to estimate the KS entropy and a lower bound of it, a sort of Shannon's entropy per unit of time, from the recurrence times of chaotic systems. One formula provides the KS entropy and is more theoretically oriented since one has to measure also the low probable very long returns. The other provides a lower bound for the KS entropy and is more experimentally oriented since one has to measure only the high probable short returns. These formulas are a consequence of the fact that the series of returns do contain the same information of the trajectory that generated it. That suggests that recurrence times might be valuable when making models of complex systems

    Tumor-Selective and Self-Activating Chemiluminescent Photosensitizers for Photodynamic Therapy

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    Application of light in chemistry presents an active field of research with a very promising outlook, particularly in technology and medicine. Molecules which mediate the transfer of light to another molecule (photosensitizers) are the cornerstone of exploitation of light. The current state of research and recent progress in applications of photosensitizers in diverse fields are documented in twelve chapters written by scientists from around the world. Chapter 1 gives a general overview on the applications of photosensitizers in synthetic organic chemistry. This review is followed by Chapters 2-7, which deal with the various applications of photosensitizers in medicine, in particular for photodynamic cancer therapy. The subsequent Chapters 8-12 cover different aspects of applications of photosensitizers in material science, such as for dye-sensitized solar cells and photo-responsive materials

    Synthesis of the first thieno-δ-carboline. Fluorescence studies in solution and in lipid vesicles

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    The first thieno-δ-carboline (6,8,9-trimethyl-5H-pyrido[3,2-b]thieno[3,2-f]indole) was prepared in good yield (70%) by intramolecular palladium-assisted cyclization of an ortho-chlorodiarylamine. The latter was in turn selectively synthesized in high yield (90%) by C–N palladiumcatalyzed cross-coupling of 3-bromo-2-chloropyridine with, the also prepared, 6-amino-2,3,7-trimethylbenzo[b]thiophene. Fluorescence studies in solution show that thieno-δ-carboline has a solvatochromic behaviour. Despite the low fluorescence quantum yields in solution, studies of its incorporation in lipid vesicles of DPPC, DOPE and DODAB indicate that thienocarboline is located mainly inside the lipid bilayer, exhibiting different behaviours in gel or liquid-crystalline phases. Our studies are useful for the incorporation of thienocarboline in liposomes and for controlled drug release assays, due to its biological activity

    Salicornia ramosissima: Secondary metabolites and protective effect against acute testicular toxicity

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    AbstractSalicornia ramosissima J. Woods is a salt tolerant plant currently used in the human diet, whose genus not only displays great potential as a crop plant in deserts and highly saline soils, but also has value in traditional medicine and exhibits promising biological activities. The present study was designed to evaluate the effect of S. ramosissima ethanolic extract on carbon tetrachloride (CCl4)-induced testicular damage in a mouse model and identify secondary metabolites present in the tested extract. The histopathological analysis showed that the treatment with the ethanolic extract prior to CCl4 administration prevented significantly the architectural disorder of seminiferous epithelium and germ cell exfoliation. The phytochemical study allowed the identification of known phenolic and aliphatic compounds [ethyl linolenoate (1), sitostanol (2), octadecyl (3) and eicosanyl (4) (E)-ferulates, ethyl (E)-2-hydroxycinnamate (5), scopoletin (6), a triacylglycerol of tetracosanoic acid (7)], and three new compounds: saliramoester, a long chain triester (8), saliramophenone, a propiophenone derivative (9) and saliramopyrrole a pyrrole-3-carbaldehyde derivative (10). Their chemical structures were elucidated using detailed spectroscopic studies (1D and 2D NMR and MS). These results enhance the value of S. ramosissima as an excellent source of structurally interesting phytochemicals and as protective agent against testicular toxicity

    Non-transitive maps in phase synchronization

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    Concepts from the Ergodic Theory are used to describe the existence of non-transitive maps in attractors of phase synchronous chaotic systems. It is shown that for a class of phase-coherent systems, e.g. the sinusoidally forced Chua's circuit and two coupled R{\"o}ssler oscillators, phase synchronization implies that such maps exist. These ideas are also extended to other coupled chaotic systems. In addition, a phase for a chaotic attractor is defined from the tangent vector of the flow. Finally, it is discussed how these maps can be used to real time detection of phase synchronization in experimental systems

    An outflow in the Seyfert ESO 362-G18 revealed by Gemini-GMOS/IFU observations

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    Indexación: Scopus.We present two-dimensional stellar and gaseous kinematics of the inner 0.7 × 1.2 kpc2 of the Seyfert 1.5 galaxy ESO 362-G18, derived from optical (4092-7338 Å) spectra obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈ 170 pc and spectral resolution of 36 km s-1. ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the [O III] emission shows a fan-shaped extension of ≈ 10′′ to the SE. We detect the [O III] doublet, [N II] and Hα emission lines throughout our field of view. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of ≈ 137° and is centred approximately on the continuum peak. The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122° to 139°, projected velocity amplitudes of the order of 100 km s-1, and a mean velocity dispersion of 100 km s-1. A double-Gaussian fit to the [O III]λ5007 and Hα lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight velocities 100-250 km s-1 higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4 × 10-2 M⊙ yr-1 in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2 × 10-2 M⊙ yr-1. The total ionized gas mass within ∼84 pc of the nucleus is 3.3 × 105 M⊙; infall velocities of ∼34 km s-1 in this gas would be required to feed both the outflow and SMBH accretion. © ESO 2018.https://www.aanda.org/articles/aa/abs/2018/06/aa31671-17/aa31671-17.htm

    Interferon-λ restricts West Nile virus neuroinvasion by tightening the blood-brain barrier

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    Although interferon-λ [also known as type III interferon or interleukin-28 (IL-28)/IL-29] restricts infection by several viruses, its inhibitory mechanism has remained uncertain. We used recombinant interferon-λ and mice lacking the interferon-λ receptor (IFNLR1) to evaluate the effect of interferon-λ on infection with West Nile virus, an encephalitic flavivirus. Cell culture studies in mouse keratinocytes and dendritic cells showed no direct antiviral effect of exogenous interferon-λ, even though expression of interferon-stimulated genes was induced. We observed no differences in West Nile virus burden between wild-type and Ifnlr1-/- mice in the draining lymph nodes, spleen, or blood. We detected increased West Nile virus infection in the brain and spinal cord of Ifnlr1-/- mice, yet this was not associated with a direct antiviral effect in mouse neurons. Instead, we observed an increase in blood-brain barrier permeability in Ifnlr1-/- mice. Treatment of mice with pegylated interferon-λ2 resulted in decreased blood-brain barrier permeability, reduced West Nile virus infection in the brain without affecting viremia, and improved survival against lethal virus challenge. An in vitro model of the blood-brain barrier showed that interferon-λ signaling in mouse brain microvascular endothelial cells increased transendothelial electrical resistance, decreased virus movement across the barrier, and modulated tight junction protein localization in a protein synthesis- and signal transducer and activator of transcription 1 (STAT1)-independent manner. Our data establish an indirect antiviral function of interferon-λ in which noncanonical signaling through IFNLR1 tightens the blood-brain barrier and restricts viral neuroinvasion and pathogenesis

    Digestible lysine effects on gene expression by Japanese quails in the pre-laying phase

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    This study aimed to determine the effects of digestible lysine levels in the diets of Japanese quail (Coturnix coturnix japonica) on performance, blood parameters and the expression of insulin-like growth factor I, and growth hormone receptor (GHR), apolipoprotein A-I (APOA-I), acetyl-CoA-carboxylase (ACC), and fatty acid synthase (FAS) genes. A total of 288 seven-day-old female Japanese quails were randomly assigned to one of three diets that contained 0.8%, 1.10%, or 1.40% digestible lysine. The birds were slaughtered at 42 days old, and relative gene expression was evaluated in the liver by qRT-PCR using the 2-ΔCT method. Lysine supplementation had no effect on weight gain and feed conversion. Abdominal fat was lower in birds supplemented with 0.8% digestible lysine than those supplemented with 1.10% and 1.40%. Increased total cholesterol and triglycerides were elevated in quails that received supplementation of 1.10% digestible lysine compared with the other diets. High density lipoproteins were decreased in birds that received 0.8% digestible lysine. Quails fed with 1.40% digestible lysine had greater expression of GHR and APOA-I than quails fed diets with 0.8 and 1.10% (P <0.05). The greatest expressions of ACC and FAS were observed in the liver of quails fed with 0.8% digestible lysine. The current results suggest that lysine supplementation in the pre-laying phase allows birds to deposit muscle mass to reach the optimal conformation and body fatness that provides an energetic reserve for the productive phase by modulating the expression of genes related to growth and lipid metabolism. Keywords: Coturnix coturnix japonica, growth, growth hormone, lipid synthesis, lipid metabolis

    Arbuscular Mycorrhiza Extraradical Mycelium Promotes Si and Mn Subcellular Redistribution in Wheat Grown under Mn Toxicity

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    Abstract: Manganese (Mn) and aluminum (Al) toxicities are serious edaphic limitations to crop production in acidic soils. Excess Mn can be countered using a stress-adapted soil microbiota that establish symbiotic relationships with native plants. The arbuscular mycorrhizal fungi (AMF) associated with Lolium rigidum L. develop extraradical mycelia (ERM) that quickly colonize wheat and lead to greater shoot growth by promoting stress-evading mechanisms that are not yet completely explained. In the present study, wheat growth was assessed after 3 weeks on disturbed and undisturbed (intact ERM) acidic soil where the native non-mycotrophic Silene gallica L. or strongly mycotrophic L. rigidum were previously developed. The physiological and biochemical mechanisms responsible for increased growth were analyzed by assessing wheat leaf chlorophyll content, photosystem II quantum yield and performance index, enzymatic activity of ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR), guaiacol peroxidase (GPX), superoxide dismutase (SOD) and contents and subcellular localization of Mn, Mg, Si and K. The soil from native plants had a beneficial effect on shoot weight and chlorophyll levels. The highest benefits were obtained for wheat grown in soil with intact ERM associated with L. rigidum. In this condition, where earlier mycorrhization was favored, the Mn content decreased, alongside the content of Si, while the Mg/Mn ratio increased. Mn was redirected to the apoplast, while Si was redirected to the symplast. The activity of APX, GPX and SOD increased, probably due to increased metabolic growth (higher shoot weight and chlorophyll content). Understanding the mechanisms induced by native AMF responsible for increasing wheat performance can contribute to the establishment of sustainable approaches for crop production in acidic soils with Mn toxicity. The use of native plant AMF developers can improve the sustainable use of natural resources in the scope of greener agricultural practice

    Cross-language high similarity search using a conceptual thesaurus

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    This work addresses the issue of cross-language high similarity and near-duplicates search, where, for the given document, a highly similar one is to be identified from a large cross-language collection of documents. We propose a concept-based similarity model for the problem which is very light in computation and memory. We evaluate the model on three corpora of different nature and two language pairs English-German and English-Spanish using the Eurovoc conceptual thesaurus. Our model is compared with two state-of-the-art models and we find, though the proposed model is very generic, it produces competitive results and is significantly stable and consistent across the corpora.This work was done in the framework of the VLC/CAMPUS Microcluster on Multimodal Interaction in Intelligent Systems and it has been partially funded by the European Commission as part of the WIQ-EI IRSES project (grant no. 269180) within the FP 7 Marie Curie People Framework, and by the Text-Enterprise 2.0 research project (TIN2009-13391-C04-03). The research work of the second author is supported by the CONACyT 192021/302009 grantGupta, P.; Barrón Cedeño, LA.; Rosso, P. (2012). Cross-language high similarity search using a conceptual thesaurus. En Information Access Evaluation. Multilinguality, Multimodality, and Visual Analytics. Springer Verlag (Germany). 7488:67-75. https://doi.org/10.1007/978-3-642-33247-0_8S6775748
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