Influence of endocrine disrupting chemicals on adipogénesis

Indexación: Scopus; Scielo.A raíz del incremento a nivel mundial de la prevalencia de sobrepeso y obesidad tanto en adultos como en niños, con consecuencias en la salud pública, la obesidad se ha convertido en un blanco de estudio de diferentes grupos de investigación, lo que a su vez involucra el entendimiento del proceso de adipogénesis. El proceso de diferenciación de adipocitos es complejo e incluye varios pasos altamente regulados que inducen al fenotipo característico de adipocito maduro, proceso promovido por la activación de los reguladores maestros de las familias de PPARƳ y C/EBPs. La adipogénesis es afectada por diversos factores que incluyen el estado nutricional, mecanismos fisiológicos y también por factores ambientales. Por otra parte, se ha propuesto que diversos contaminantes ambientales, especialmente aquellos con actividades disruptivas endocrinas, están emergiendo como nuevos factores de riesgo para desarrollar obesidad. Químicos disruptores endocrinos son sustancias ambientales que presentan actividad biológica cuyo blanco es la alteración de la función del sistema endocrino, influyendo también en la regulación fisiológica del tejido adiposo. En la presente revisión se expondrán los diferentes disruptores endocrinos a los cuales se les ha comprobado experimentalmente que influyen en la regulación del proceso de adipogénesis.http://www.revistaavft.com/images/revistas/2018/avft_1_2018/influencia_disruptores_endocrinos.pd

Foliation of the Kottler-Schwarzschild-De Sitter Spacetime by Flat Spacelike Hypersurfaces

There exist Kruskal like coordinates for the Reissner-Nordstrom (RN) black hole spacetime which are regular at coordinate singularities. Non existence of such coordinates for the extreme RN black hole spacetime has already been shown. Also the Carter coordinates available for the extreme case are not manifestly regular at the coordinate singularity, therefore, a numerical procedure was developed to obtain free fall geodesics and flat foliation for the extreme RN black hole spacetime. The Kottler-Schwarzschild-de Sitter (KSSdS) spacetime geometry is similar to the RN geometry in the sense that, like the RN case, there exist non-singular coordinates when there are two distinct coordinate singularities. There are no manifestly regular coordinates for the extreme KSSdS case. In this paper foliation of all the cases of the KSSdS spacetime by flat spacelike hypersurfaces is obtained by introducing a non-singular time coordinate.Comment: 12 pages, 4 figure

Characterization Of The Crotalus Durissus Terrificus Venom By Atomic Force Microscopy

A preliminary analysis of the morphology of crude CDT venom was performed using atomic force microscopy (AFM). As a result, a direct measurement of the forces between the surface of the venom crystals and a sharp probe tip was achieved.20413171321Azevedo Marques, M.M., Cupo, P., Coimbra, T.M., Hering, S.E., Rossi, M.A., Laure, C.J., (1985) Toxicon, 23, p. 631Sanchez, E.E., Soliz, L.A., Susana Ramirez, M., Perez, J.C., (2001) Toxicon, 39, p. 523Soares, A.M., Mancin, A.C., Cecchini, A.L., Arantes, E.C., Franca, S.C., Gutierrez, J.M., Giglio, J.R., (2001) Int. J. Biochem. Cell Biol., 33, p. 877Choumet, V., Lafaye, P., Demangel, C., Bon, C., Mazie, J.C., (1999) Biol. Chem., 380, p. 561Sanchez, S.A., Chen, Y., Muller, J.D., Gratton, E., Hazlett, T.L., (2001) Biochemistry, 40, p. 6903Sharma, S., Jabeen, T., Singh, J.K., Bredhorst, R., Vogel, C.W., Betzel, C., Singh, T.P., (2001) Acta Crystallogr., Sect. D: Biol. Crystallogr., 57, p. 596Nonato, M.C., Garrat, R.C., Mascarenhas, Y.P., Jesus, W.D.P., Assakura, M.T., Serrano, S.M.T., Oliva, G., (2001) Biol. Crystallogr., D, 57, p. 599Arni, R.K., Ward, R.J., (1996) Toxicon, 34, p. 827Souza, D.H.F., Selistre-deAraujo, H.S., Garratt, R.C., (2000) Toxicon, 38, p. 1307Binning, G., Coate, C.F., Gerber, G., (1986) Phys. Rev. Lett., 56, p. 930Baranauskas, V., Vidal, B.C., Parizotto, N.A., (1998) Appl. Biochem. Biotechnol., 69, p. 91Baranauskas, V., Garavello-Freitas, I., Jingguo, Z., Cruz-Hofling, M.A., (2001) J. Vac. Sci. Technol. A, 19, p. 104

On two superintegrable nonlinear oscillators in N dimensions

We consider the classical superintegrable Hamiltonian system given by $H=T+U={p^2}/{2(1+\lambda q^2)}+{{\omega}^2 q^2}/{2(1+\lambda q^2)}$, where U is known to be the "intrinsic" oscillator potential on the Darboux spaces of nonconstant curvature determined by the kinetic energy term T and parametrized by {\lambda}. We show that H is Stackel equivalent to the free Euclidean motion, a fact that directly provides a curved Fradkin tensor of constants of motion for H. Furthermore, we analyze in terms of {\lambda} the three different underlying manifolds whose geodesic motion is provided by T. As a consequence, we find that H comprises three different nonlinear physical models that, by constructing their radial effective potentials, are shown to be two different nonlinear oscillators and an infinite barrier potential. The quantization of these two oscillators and its connection with spherical confinement models is briefly discussed.Comment: 11 pages; based on the contribution to the Manolo Gadella Fest-60 years-in-pucelandia, "Recent advances in time-asymmetric quantum mechanics, quantization and related topics" hold in Valladolid (Spain), 14-16th july 201

Particle motion in the field of a five-dimensional charged black hole

In this paper, we have investigated the geodesics of neutral particles near a five-dimensional charged black hole using a comparative approach. The effective potential method is used to determine the location of the horizons and to study radial and circular trajectories. This also helps us to analyze the stability of radial and circular orbits. The radius of the innermost stable circular orbits have also been determined. Contrary to the case of massive particles for which, the circular orbits may have up to eight possible values of specific radius, we find that the photons will only have two distinct values for the specific radii of circular trajectories. Finally we have used the dynamical systems analysis to determine the critical points and the nature of the trajectories for the timelike and null geodesics.Comment: 15 pages, accepted for publication in Astrophysics and Space Scienc

Electroweak Corrections to the Charged Higgs Boson Decay into Chargino and Neutralino

The electroweak corrections to the partial widths of the $H^+ \to \tilde{\chi}^+_i \tilde{\chi}_j^0 (i=1,j=1,2)$ decays including one-loop diagrams of the third generation quarks and squarks, are investigated within the Supersymmetric Standard Model. The relative corrections can reach the values about 10%, therefore they should be taken into account for the precise experimental measurement at future colliders.Comment: 21 pages, 6 eps figures, 1 Latex fil

Black hole solutions in F(R) gravity with conformal anomaly

In this paper, we consider $F(R)=R+f(R)$ theory instead of Einstein gravity with conformal anomaly and look for its analytical solutions. Depending on the free parameters, one may obtain both uncharged and charged solutions for some classes of $F(R)$ models. Calculation of Kretschmann scalar shows that there is a singularity located at $r=0$, which the geometry of uncharged (charged) solution is corresponding to the Schwarzschild (Reissner-Nordstr\"om) singularity. Further, we discuss the viability of our models in details. We show that these models can be stable depending on their parameters and in different epoches of the universe.Comment: 12 pages, one figur