3,101 research outputs found

    Review of the temporal and geographical distribution of measles virus genotypes in the prevaccine and postvaccine eras

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    Molecular epidemiological investigation of measles outbreaks can document the interruption of endemic measles transmission and is useful for establishing and clarifying epidemiological links between cases in geographically distinct clusters. To determine the distribution of measles virus genotypes in the prevaccine and postvaccine eras, a literature search of biomedical databases, measles surveillance websites and other electronic sources was conducted for English language reports of measles outbreaks or genetic characterization of measles virus isolates. Genotype assignments based on classification systems other than the currently accepted WHO nomenclature were reassigned using the current criteria. This review gives a comprehensive overview of the distribution of MV genotypes in the prevaccine and postvaccine eras and describes the geographically diverse distribution of some measles virus genotypes and the localized distributions of other genotypes

    Review of the temporal and geographical distribution of measles virus genotypes in the prevaccine and postvaccine eras

    Get PDF
    Molecular epidemiological investigation of measles outbreaks can document the interruption of endemic measles transmission and is useful for establishing and clarifying epidemiological links between cases in geographically distinct clusters. To determine the distribution of measles virus genotypes in the prevaccine and postvaccine eras, a literature search of biomedical databases, measles surveillance websites and other electronic sources was conducted for English language reports of measles outbreaks or genetic characterization of measles virus isolates. Genotype assignments based on classification systems other than the currently accepted WHO nomenclature were reassigned using the current criteria. This review gives a comprehensive overview of the distribution of MV genotypes in the prevaccine and postvaccine eras and describes the geographically diverse distribution of some measles virus genotypes and the localized distributions of other genotypes

    Modulational instability in dispersion-kicked optical fibers

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    We study, both theoretically and experimentally, modulational instability in optical fibers that have a longitudinal evolution of their dispersion in the form of a Dirac delta comb. By means of Floquet theory, we obtain an exact expression for the position of the gain bands, and we provide simple analytical estimates of the gain and of the bandwidths of those sidebands. An experimental validation of those results has been realized in several microstructured fibers specifically manufactured for that purpose. The dispersion landscape of those fibers is a comb of Gaussian pulses having widths much shorter than the period, which therefore approximate the ideal Dirac comb. Experimental spontaneous MI spectra recorded under quasi continuous wave excitation are in good agreement with the theory and with numerical simulations based on the generalized nonlinear Schr\"odinger equation

    Circulating adhesion molecules and arterial stiffness

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    Aim: VCAM-1 and ICAM-1 are two important members of the immunoglobulin gene superfamily of adhesion molecules, and their potential role as biomarkers of diagnosis, severity and prognosis of cardiovascular disease has been investigated in a number of clinical studies. The aim of the present study was to determine the relationship between circulating ICAM-1 and VCAM-1 levels and aortic stiffness in patients referred for echocardiographic examination. Methods: Aortic distensibility was determined by echocardiography using systolic and diastolic aortic diameters in 63 consecutive patients referred for echocardiography. Venous samples were collected in the morning after a 12-hour overnight fast, and serum concentrations of ICAM-1 and VCAM-1 were measured using commercial enzyme immunoassay kits. Results: Data of a total of 63 participants (mean age 55.6 ± 10.5 years, 31 male) were included in the study. Circulating levels of adhesion molecules were VCAM-1: 12.604 ± 3.904 ng/ml and ICAM-1: 45.417 ± 31.429 ng/ml. We were unable to demonstrate any correlation between indices of aortic stiffness and VCAM-1 and ICAM-1 levels. Conclusion: The role of soluble adhesion molecules in cardiovascular disease has not been fully established and clinical studies show inconsistent results. Our results indicate that levels of circulating adhesion molecules cannot be used as markers of aortic stiffness in patients

    Condensate fraction in liquid 4He at zero temperature

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    We present results of the one-body density matrix (OBDM) and the condensate fraction n_0 of liquid 4He calculated at zero temperature by means of the Path Integral Ground State Monte Carlo method. This technique allows to generate a highly accurate approximation for the ground state wave function Psi_0 in a totally model-independent way, that depends only on the Hamiltonian of the system and on the symmetry properties of Psi_0. With this unbiased estimation of the OBDM, we obtain precise results for the condensate fraction n_0 and the kinetic energy K of the system. The dependence of n_0 with the pressure shows an excellent agreement of our results with recent experimental measurements. Above the melting pressure, overpressurized liquid 4He shows a small condensate fraction that has dropped to 0.8% at the highest pressure of p = 87 bar.Comment: 12 pages. 4 figures. Accepted for publication on "Journal of Low Temperature Physics

    Heteroclinic structure of parametric resonance in the nonlinear Schr\"odinger equation

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    We show that the nonlinear stage of modulational instability induced by parametric driving in the {\em defocusing} nonlinear Schr\"odinger equation can be accurately described by combining mode truncation and averaging methods, valid in the strong driving regime. The resulting integrable oscillator reveals a complex hidden heteroclinic structure of the instability. A remarkable consequence, validated by the numerical integration of the original model, is the existence of breather solutions separating different Fermi-Pasta-Ulam recurrent regimes. Our theory also shows that optimal parametric amplification unexpectedly occurs outside the bandwidth of the resonance (or Arnold tongues) arising from the linearised Floquet analysis

    Supercritical Fluid fractionation of mentha suaveolens: concentration of functional properties

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    Supercritial Antisolvent Fractionation process was optimiced for the concentration of Mentha suaveolens bioactives in two different fractions. Their composition was analysed with HPLC. The antimicrobial activity of these fractions was assayed. The SAF process fractionated M. suaveolens tincture in two enriched fractions in different bioactives concentrating those with antimicrobial activity in one of them.  El proceso de Fraccionamiento SupercrĂ­tico Antidisolvente  fue optimizado para la concentrar bioactivos de Mentha suaveolens en dos diferentes fracciones. Su composiciĂłn fue analizada con HPLC. La actividad antimicrobiana de estas fracciones fue ensayada. El proceso supercrĂ­tico permitiĂł fraccionar la tintura de esta planta en 2 fracciones enrriqueciendolas en diferentes bioactivos y concentrando en uno de ellos los compuestos con actividad antimicrobiana.  &nbsp

    Supercritical Fluid fractionation of mentha suaveolens: concentration of functional properties

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    Supercritial Antisolvent Fractionation process was optimiced for the concentration of Mentha suaveolens bioactives in two different fractions. Their composition was analysed with HPLC. The antimicrobial activity of these fractions was assayed. The SAF process fractionated M. suaveolens tincture in two enriched fractions in different bioactives concentrating those with antimicrobial activity in one of them.  El proceso de Fraccionamiento SupercrĂ­tico Antidisolvente  fue optimizado para la concentrar bioactivos de Mentha suaveolens en dos diferentes fracciones. Su composiciĂłn fue analizada con HPLC. La actividad antimicrobiana de estas fracciones fue ensayada. El proceso supercrĂ­tico permitiĂł fraccionar la tintura de esta planta en 2 fracciones enrriqueciendolas en diferentes bioactivos y concentrando en uno de ellos los compuestos con actividad antimicrobiana.  &nbsp

    Effects of the mean particle size in the deflagration index estimation for cornstarch dust

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    The National Fire Protection Association (NFPA) defines the dust explosions as a “credible risk”. Hence, to meet the challenge to prevent and protect from the catastrophic effects of these phenomena, it is fundamental to know what are the characteristics and the burning conditions regarding the combustible dusts that could have an effect on the explosion violence. The KSt, also known as deflagration index, is one of the relevant parameters in dust explosions, together with the maximum explosion overpressure generated in the test chamber, the minimumignition energy and so on. In particular, the deflagration index measures the relative explosion severity and it is used in the design of the dust venting protection equipment. However, one of the criticalities of such a parameter is that is strongly affected by the particle mean diameter. Hence, in the following, it will be preliminary presented the validation of a single particle spherical model able to predict the variation of the deflagration index with the increasing mean particle size knowing just one experimental KSt value
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