Rational approximations of f(R)f(R) cosmography through Pad\'e polynomials

We consider high-redshift $f(R)$ cosmography adopting the technique of polynomial reconstruction. In lieu of considering Taylor treatments, which turn out to be non-predictive as soon as $z>1$, we take into account the Pad\'e rational approximations which consist in performing expansions converging at high redshift domains. Particularly, our strategy is to reconstruct $f(z)$ functions first, assuming the Ricci scalar to be invertible with respect to the redshift $z$. Having the thus-obtained $f(z)$ functions, we invert them and we easily obtain the corresponding $f(R)$ terms. We minimize error propagation, assuming no errors upon redshift data. The treatment we follow naturally leads to evaluating curvature pressure, density and equation of state, characterizing the universe evolution at redshift much higher than standard cosmographic approaches. We therefore match these outcomes with small redshift constraints got by framing the $f(R)$ cosmology through Taylor series around $z\simeq 0$. This gives rise to a calibration procedure with small redshift that enables the definitions of polynomial approximations up to $z\simeq 10$. Last but not least, we show discrepancies with the standard cosmological model which go towards an extension of the $\Lambda$CDM paradigm, indicating an effective dark energy term evolving in time. We finally describe the evolution of our effective dark energy term by means of basic techniques of data mining.Comment: 11 pages, 14 figures, accepted for publication in JCA

Mycotoxins nivalenol and deoxynivalenol differently modulate cytokine mRNA expression in Jurkat T cells.

Deoxynivalenol (DON) and its hydroxylated form nivalenol (NIV) are Fusarium mycotoxins that occur in cereal grains alone or in combination. Several studies have shown that these metabolites affect lymphocyte functions. However, the molecular mechanisms underlying their activities are still partially known. To address this issue, we examined the influence of NIV and DON in modulating IFNc, IL-2 and IL-8 mRNA levels in Jurkat T cells. In PMA/ionomycin stimulated cells, pre-incubated with increasing concentrations of NIV, transcription was induced in the range 0.06–2 lM; higher concentrations of NIV were found non-stimulating (4 lM) or inhibitory (8 lM) for IFNc and IL-2 whereas IL-8 was still induced. DON administration elicited a similar profile for IL-8 and IFNc, whilst IL-2 mRNA was induced in a broader range of concentrations. Combination of NIV and DON at 1:1 and 1:10 ratios essentially restored the cytokine transcriptional pattern observed with NIV alone but the level of transcripts, with the exception of IL-8, peaked at lower concentrations suggesting interactive effects. Moreover both mycotoxins caused inhibition of cell proliferation, mediated by induction of apoptosis, confirming previous results and highlighting the usefulness of Jurkat as a T-cell model to study the effects of mycotoxins on the immune functions in humans

Trichothecenes NIV and DON modulate the maturation of murinedendritic cells

Nivalenol (NIV) and Deoxynivalenol (DON), mycotoxins of the trichothecene family are considered very common food contaminants. In this work, we investigated whether the immunotoxic effects ascribed to these trichothecenes may be mediated by perturbations in the activity of dendritic cells (DCs). Murine bone marrow-derived DCs were used to evaluate the effects of NIV and DON on the LPS-induced maturation process.We found that the expression of the class II MHC and of the accessory CD11c molecules, but not of the costimulatory CD86 marker, was down-regulated by NIV and DON exposure in LPS-treated DCs, as well as nitric oxide (NO) production. Interestingly, NIV, but not DON, induced DC necrosis. Moreover, the analysis of the cytokine pattern showed that IL-12 and IL-10 expressions induced by LPS exposure were suppressed by both trichothecenes in a dose-dependent fashion. On the other hand, the secretion of the proinflammatory cytokine TNFa was increased as a direct consequence of DON and NIV exposure. Taken together, our data indicated that the immunotoxicity of NIV and DON was related to the capacity of both trichothecenes to interfere with phenotypic and functional features of maturing DCs

A Continuum Approach to the Nonlinear In-Plane Galloping of Shallow Flexible Cables

The aeroelastic stability of horizontal, suspended, shallow, iced cables is studied via a continuum model. Both external and internal damping, consistent with the Rayleigh model, are taken into account. The quasi-static theory of the aerodynamic forces is applied. An in-plane nonlinear model of galloping is formulated, displaying the importance of internal damping, both on the critical velocity and on the limit-cycle amplitude. A perturbation procedure is developed for nonlinear analysis in nonresonant conditions (monomodal galloping). The modification of the galloping mode due to quadratic nonlinearities is studied, and its real or complex character is discussed

Unusual cytotoxic sulfated cadinene-type sesquiterpene glycosides from cottonseed (Gossypium hirsutum).

Two new sulfated cadinene-type sesquiterpene glycosides, 13-hydroxy-7-O-(60-O-sulfate-b-D-glucopyranosyl)-desoxyhemigossypol (1) and 13,15-dihydroxy-7-O-(60-O-sulfate-b-D-glucopyranosyl)-desoxyhemigossypol (2), have been isolated from whole cottonseed (Gossypium hirsutum). Their structures, which possess an unusual 6-O-sulfate-glucopyranosyl moiety, were determined through the interpretation of 2D NMR spectral data and H/D exchange ESI-MS experiments. Compounds 1 and 2 were screened for their toxicity on Jurkat cells. Both compounds inhibited cellular proliferation with IC50 values of 8.1 and 4.2 mg, respectively

Immune effects of four Fusarium-Toxins ( FB1, ZEA, NIV, DON) on the proliferation of Jurkat cells and porcine lymphocytes: in vitro study.

Fusarium toxins are secondary metabolites produced by fungi belonging to Fusarium spp., commonly found as contaminants in products of vegetable origin, particularly in cereal grains, in regions with temperate climate in Europe, America and Asia. Numerous toxic effects are attributed to mycotoxins both in humans and animals, such as mutagenic, cencerogenic and teratogenic properties. Moreover, some of them can alter normal immune responses when they are present in food at levels lower than those necessary to cause the symptoms of mycotoxicosis. In the present work, we evaluated the immunomodulatory effects of four Fusarium toxins (FB1, ZEA, NIV, DON) using two different experimental models: Jurkat cells and porcine lymphocytes. In addition to the activity of single mycotoxins, we evaluated possible interactions between Fusarium toxins to reproduce experimental conditions in vitro as near as possible to field conditions. Our results revealed the immunomodulatory properties of the mycotoxin objects of the current study. They also underline the interest in studying possible interactions among different mycotoxins, particularly among those mainly present in food such as Fusarium mycotoxins, not only regarding their toxicodinamic aspect but also to define tolerable maximum levels of Fusarium toxins in food

Accretion Disk Luminosity for Black Holes Surrounded by Dark Matter with Anisotropic Pressure

We investigate the luminosity of the accretion disk of a static black hole surrounded by dark matter with anisotropic pressure. We calculate all basic orbital parameters of test particles in the accretion disk, such as angular velocity, angular momentum, energy, and radius of the innermost circular stable orbit as functions of the dark matter density, radial pressure, and anisotropic parameter, which establishes the relationship between the radial and tangential pressures. We show that the presence of dark matter with anisotropic pressure makes a noticeable difference in the geometry around a Schwarzschild black hole, affecting the radiative flux, differential luminosity, and spectral luminosity of the accretion disk

Grape pomace polyphenols improve insulin response to a standard meal in healthy individuals: A pilot study

Dietary polyphenols have beneficial effects on glucose/lipid metabolism in subjects at high risk to develop type 2 diabetes; however, the underlying mechanisms are not clear. We aimed to evaluate: 1) the acute effects of the consumption of a drink rich in polyphenols from red grape pomace (RGPD) on glucose/insulin and triglyceride responses to a standard meal in healthy individuals, and, 2) the relationship between plasma levels of phenolic metabolites and metabolic parameters