458 research outputs found

    A new model for evolution in a spatial continuum

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    We investigate a new model for populations evolving in a spatial continuum. This model can be thought of as a spatial version of the Lambda-Fleming-Viot process. It explicitly incorporates both small scale reproduction events and large scale extinction-recolonisation events. The lineages ancestral to a sample from a population evolving according to this model can be described in terms of a spatial version of the Lambda-coalescent. Using a technique of Evans(1997), we prove existence and uniqueness in law for the model. We then investigate the asymptotic behaviour of the genealogy of a finite number of individuals sampled uniformly at random (or more generally `far enough apart') from a two-dimensional torus of side L as L tends to infinity. Under appropriate conditions (and on a suitable timescale), we can obtain as limiting genealogical processes a Kingman coalescent, a more general Lambda-coalescent or a system of coalescing Brownian motions (with a non-local coalescence mechanism).Comment: 63 pages, version accepted to Electron. J. Proba

    Luminescent properties of Bi-doped polycrystalline KAlCl4

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    We observed an intensive near-infrared luminescence in Bi-doped KAlCl4 polycrystalline material. Luminescence dependence on the excitation wavelength and temperature of the sample was studied. Our experimental results allow asserting that the luminescence peaked near 1 um belongs solely to Bi+ ion which isomorphically substitutes potassium in the crystal. It was also demonstrated that Bi+ luminescence features strongly depend on the local ion surroundings

    FTIR study of thermally induced magnetostructural transitions in breathing crystals

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    © 2015 American Chemical Society. "Breathing crystals" based on copper(II) hexafluoroacetylacetonates and pyrazolyl-substituted nitronyl nitroxides comprise the exchange-coupled clusters within the polymeric chains. Owing to an interplay of exchange interaction between copper(II) and nitroxide spins and Jahn-Teller nature of copper(II) complex, the breathing crystals demonstrate thermally and light-induced magnetostructural transitions in many aspects similar to the classical spin crossover. Herewith, we report the first application of variable temperature (VT) far/mid Fourier transform infrared (FTIR) spectroscopy and mid FTIR microscopy to breathing crystals. This VT-FTIR study was aimed toward clarification of the transitions mechanism previously debated on the basis of superconducting quantum interference device, X-ray diffraction, and electron paramagnetic resonance data. VT-FTIR showed the onset of new vibrational bands during phase transitions occurring at the expense of several existing ones, whose intensity was significantly reduced. The most pronounced spectral changes were assigned to corresponding vibrational modes using quantum chemical calculations. A clear-cut correlation was found between temperature-dependent effective magnetic moment of studied compounds and the observed VT-FTIR spectra. Importantly, VT-FTIR confirmed coexistence of two types of copper(II)-nitroxide clusters during gradual magnetostructural transition. Such clusters correspond to weakly coupled and strongly coupled spin states, whose relative contribution depends on temperature. The pronounced difference in the VT-FTIR spectra of two states in breathing crystals is a fingerprint of magnetostructural transition, and understanding of these characteristics achieved by us will be useful for future studies of breathing crystals as well as their diamagnetic analogues

    Inferring the role of transcription factors in regulatory networks

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    <p>Abstract</p> <p>Background</p> <p>Expression profiles obtained from multiple perturbation experiments are increasingly used to reconstruct transcriptional regulatory networks, from well studied, simple organisms up to higher eukaryotes. Admittedly, a key ingredient in developing a reconstruction method is its ability to integrate heterogeneous sources of information, as well as to comply with practical observability issues: measurements can be scarce or noisy. In this work, we show how to combine a network of genetic regulations with a set of expression profiles, in order to infer the functional effect of the regulations, as inducer or repressor. Our approach is based on a consistency rule between a network and the signs of variation given by expression arrays.</p> <p>Results</p> <p>We evaluate our approach in several settings of increasing complexity. First, we generate artificial expression data on a transcriptional network of <it>E. coli </it>extracted from the literature (1529 nodes and 3802 edges), and we estimate that 30% of the regulations can be annotated with about 30 profiles. We additionally prove that at most 40.8% of the network can be inferred using our approach. Second, we use this network in order to validate the predictions obtained with a compendium of real expression profiles. We describe a filtering algorithm that generates particularly reliable predictions. Finally, we apply our inference approach to <it>S. cerevisiae </it>transcriptional network (2419 nodes and 4344 interactions), by combining ChIP-chip data and 15 expression profiles. We are able to detect and isolate inconsistencies between the expression profiles and a significant portion of the model (15% of all the interactions). In addition, we report predictions for 14.5% of all interactions.</p> <p>Conclusion</p> <p>Our approach does not require accurate expression levels nor times series. Nevertheless, we show on both data, real and artificial, that a relatively small number of perturbation experiments are enough to determine a significant portion of regulatory effects. This is a key practical asset compared to statistical methods for network reconstruction. We demonstrate that our approach is able to provide accurate predictions, even when the network is incomplete and the data is noisy.</p

    Analysis of medical and social factors affecting the formation and course of co-infection HIV, tuberculosis and viral hepatitis

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    Currently, HIV infection is characterized by emergence of its severe and comorbid forms. Mid-1990 HIV epidemics was expanded due to injection drug users who brought viral hepatitis C to the cohort. Along with developing immunosuppression, opportunistic and AIDS-defining diseases, including tuberculosis emerged. Various combinations of coinfections (HIV infection+tuberculosis±viral hepatitis) affect clinical manifestations and clinical score, reduce the therapeutic efficacy and worsen disease prognosis.Objective: to study an impact medical and social factors on course of TB-co-infection associated with immunosuppression related to HIV infection and viral hepatitis.Materials and methods. Comorbid cases (HIV infection, tuberculosis and chronic hepatitis) dominated by verified TB-infection (n = 137) were analyzed.Results. It was shown that socially maladapted young people with previous experience of intravenous drug and alcohol abuse dominated among subjects with co-infections, half of which were held in penal institutions. More-over, the mean CD4 lymphocyte level in generalized tuberculosis was significantly lower than in patients with significantly reaching 164±21.5 cells. In addition, lung-specific lesions were observed in 73.4% of patients with generalized tuberculosis that developed by initial targeting of the lymphoid system followed by affecting other organs, mainly the central nervous system, urinary system and abdominal organs. Introduction of antiretroviral drugs to anti-TB therapy reduced mortality rate by 8 times. Viral hepatitis was the most common concomitant disease found in co-infected patients, with dominating viral hepatitis C both as a mono-infection (86.8%) as well as in combination with viral hepatitis B (9.43%). In addition, co-morbid viral hepatitis resulted in progression of TB infection affected due to intra-thoracic lymph nodes being involved in tuberculosis process as well as development of opportunistic diseases due to a markedly decreased CD4 cell count. Analysis of potentially aggravating risk factors for developing hepatotoxicity (viral hepatitis, combined treatment with anti-TB and anti-retroviral drugs) did not reveal their any additional negative impact on hepatic functions. Thus, use of a combination therapy with anti-TB and anti-retroviral drugs in co-infected patients was shown to be safe and not accompanied by a high rate of hepatotoxic reactions

    Enhancing reductive cleavage of aromatic carboxamides

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    [GRAPHICS] A set of aromatic and especially heteroaromatic N-benzyl carboxamides, derived from naphthalene, pyridine, pyrazine, and quinoline, and the corresponding tert-butyl acylcarbamates have been synthesized and studied by cyclic voltammetry with respect to facilitated reduction. The latter undergo regiospecific cleavage of their C(O)-N bonds under very mild reductive conditions with formation of Boc-protected (benzyl)amine in most cases in nearly quantitative yields, Examples of preparative cleavage by controlled potential electrolysis, activated aluminum, and NaBH4 are given

    Enfermedad de Gaucher en Argentina: un informe del Registro Internacional de Gaucher y del Grupo Argentino de Diagnóstico y Tratamiento de la Enfermedad de Gaucher

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    La Enfermedad de Gaucher por su baja frecuencia está incluida dentro de las enfermedades huérfanas. En 1991 comenzó el ingreso de pacientes en el Registro Internacional de Gaucher. En 1992 se incorporaron los primeros dos pacientes de Latinoamérica. En 2006 se creó el Grupo Argentino de Diagnóstico y Tratamiento de la Enfermedad de Gaucher siendo sus objetivos principales el entendimiento de la prevalencia, presentación, manejo y tratamiento de la Enfermedad de Gaucher en Argentina. Hasta el 1 de febrero del 2013 ingresaron al Registro Internacional 5.986 pacientes provenientes de 60 países, de los cuales 133 (2.22%) fueron argentinos. El análisis de esta publicación fue realizado sobre 133 pacientes con Enfermedad de Gaucher. Esta es la primera publicación del Grupo Argentino de Diagnóstico y Tratamiento en base a los datos del Registro Internacional. La casuística argentina mostró un predominio femenino y la forma clínica más frecuente fue el tipo 1 (97.7%, n=128). El genotipo fue identificado en 57 pacientes (42.9%), siendo el más frecuente el N370S/ otro alelo (82.5%). Entre los pacientes con datos reportados, los síntomas basales predominantes, previos al inicio del tratamiento con Imiglucerasa que predominaron fueron la esplenomegalia (100%, n=13) y la hepatomegalia (88.9%, n=8) y como citopenias más frecuentes, la trombocitopenia (64.2%, n=34) y la anemia (45.9%, n=28). La infiltración de la médula ósea como un marcador específico de enfermedad ósea se encontró en el 50% de los pacientes. En total, el 85.7% de los pacientes argentinos reciben terapia de reemplazo enzimático con Imiglucerasa, lográndose las metas terapéuticas, en la mayoría de los casos, en la última evaluación. Las metas terapéuticas más frecuentemente alcanzadas resultaron: el control de las manifestaciones óseas (dolor óseo y crisis ósea, 81.9% y 99% respectivamente) y la normalización de la hemoglobina (86.5%). La terapia de reemplazo enzimática con Imiglucerasa, a largo plazo en la población argentina demostró ser una herramienta eficaz para mejorar los parámetros clínicos y bioquímicos de la Enfermedad de Gaucher tipo1.Fil: Drelichman, G.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Fernández Escobar, Nicolás. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Basack, Nora. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Kohan, R.. Registro Argentino de Gaucher; ArgentinaFil: Watman, N.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Bolesina, M.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Elena, G.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Veber, S. E.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños Pedro Elizalde (ex Casa Cuna); ArgentinaFil: Dragosky, M.. Gobierno de la Ciudad de Buenos Aires. Hospital de Oncología Marie Curie; ArgentinaFil: Annetta, I.. Gobierno de la Ciudad de Buenos Aires. Hospital de Oncología Marie Curie; ArgentinaFil: Feliu, A.. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Sciuccati, Gabriela. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Cuello, María Fernanda. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fynn, Alcira. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; ArgentinaFil: Dodelson de Kremer, Raquel. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; ArgentinaFil: Angaroni, Celia Juana. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; ArgentinaFil: Giner Ayala, Alicia. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; ArgentinaFil: Del Valle Oller, Ana María. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Guelbert, Norberto Bernardo. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; ArgentinaFil: Delgado, María Andrea. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; ArgentinaFil: Becerra, Adriana Berónica. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de la Plata; ArgentinaFil: Oliveri, María Beatriz. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Larroudé, M.. Centro Médico TIEMPO; ArgentinaFil: Masllorens, F.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Nacional “Prof. Dr. A. Posadas"; ArgentinaFil: Szlago, M.. Fundación para el eEstudio de las Enfermedades Neurometabólicas; Argentina. Laboratorio de Neuroquímica “Dr. N. A. Chamoles”; ArgentinaFil: Schenone, A.. Laboratorio de Neuroquímica “Dr. N. A. Chamoles”; Argentina. Fundación para el eEstudio de las Enfermedades Neurometabólicas; Argentin
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