INTEGRAL and XMM-Newton observations towards the unidentified MeV source GRO J1411-64.

The COMPTEL unidentified source GRO J1411-64 was observed by INTEGRAL, and its central part, also by XMM-Newton. The data analysis shows no hint for new detections at hard X-rays. The upper limits in flux herein presented constrain the energy spectrum of whatever was producing GRO J1411-64, imposing, in the framework of earlier COMPTEL observations, the existence of a peak in power output located somewhere between 300-700 keV for the so-called low state. The Circinus Galaxy is the only source detected within the 4$\sigma$ location error of GRO J1411-64, but can be safely excluded as the possible counterpart: the extrapolation of the energy spectrum is well below the one for GRO J1411-64 at MeV energies. 22 significant sources (likelihood $> 10$) were extracted and analyzed from XMM-Newton data. Only one of these sources, XMMU J141255.6-635932, is spectrally compatible with GRO J1411-64 although the fact the soft X-ray observations do not cover the full extent of the COMPTEL source position uncertainty make an association hard to quantify and thus risky. The unique peak of the power output at high energies (hard X-rays and gamma-rays) resembles that found in the SED seen in blazars or microquasars. However, an analysis using a microquasar model consisting on a magnetized conical jet filled with relativistic electrons which radiate through synchrotron and inverse Compton scattering with star, disk, corona and synchrotron photons shows that it is hard to comply with all observational constrains. This and the non-detection at hard X-rays introduce an a-posteriori question mark upon the physical reality of this source, which is discussed in some detail.

Cystamine and cysteamine increase brain levels of BDNF in Huntington disease via HSJ1b and transglutaminase

There is no treatment for the neurodegenerative disorder Huntington disease (HD). Cystamine is a candidate drug; however, the mechanisms by which it operates remain unclear. We show here that cystamine increases levels of the heat shock DnaJ-containing protein 1b (HSJ1b) that are low in HD patients. HSJ1b inhibits polyQ-huntingtin¿induced death of striatal neurons and neuronal dysfunction in Caenorhabditis elegans. This neuroprotective effect involves stimulation of the secretory pathway through formation of clathrin-coated vesicles containing brain-derived neurotrophic factor (BDNF). Cystamine increases BDNF secretion from the Golgi region that is blocked by reducing HSJ1b levels or by overexpressing transglutaminase. We demonstrate that cysteamine, the FDA-approved reduced form of cystamine, is neuroprotective in HD mice by increasing BDNF levels in brain. Finally, cysteamine increases serum levels of BDNF in mouse and primate models of HD. Therefore, cysteamine is a potential treatment for HD, and serum BDNF levels can be used as a biomarker for drug efficacy.

El Dr. Lluís Via Boada, una vida fecunda

El Dr. Lluís Via Boada, nació en Vilafranca del Penedes en octubre de 1910, y empezó sus estudios eclesiásticos en el Seminario de Barcelona en setiembre de 1925.

BRST-invariant path integral for a spinning relativistic particle

The propagator of a relativistic spinning particle is calculated using the Becchi-Rouet-Stora-Tyutin-(BRST)-invariant path-integral formalism of Fradkin and Vilkovisky. The spinless case is considered as an introduction to the formalism.

Equivalence of reduced, Polyakov, Faddeev-Popov, and Faddeev path-integral quantization of gauge theories

A geometrical treatment of the path integral for gauge theories with first-class constraints linear in the momenta is performed. The equivalence of reduced, Polyakov, Faddeev-Popov, and Faddeev path-integral quantization of gauge theories is established. In the process of carrying this out we find a modified version of the original Faddeev-Popov formula which is derived under much more general conditions than the usual one. Throughout this paper we emphasize the fact that we only make use of the information contained in the action for the system, and of the natural geometrical structures derived from it.

Poincar-Cartan integral invariant and canonical transformation for singular lagrangians

In this work we develop the canonical formalism for constrained systems with a finite number of degrees of freedom by making use of the PoincarCartan integral invariant method. A set of variables suitable for the reduction to the physical ones can be obtained by means of a canonical transformation. From the invariance of the PoincarCartan integral under canonical transformations we get the form of the equations of motion for the physical variables of the system.

Muerte en Venecia de Thomas Mann o la via plutarquea hacia Eros

En Muerte en Venecia Thomas Mann se refiere explícitamente al Simposio y al Fedro de Platón para explicar la relación entre Gustav von Aschenbach y Tadzio, pero oculta que su novela se inspira también en el Erótico de Plutarco. ¿Por qué? El objetivo de este artículo es justamente revelar las razones de este proceder. En efecto, Plutarco elogia el amor matrimonial en el Erótico y éste no es el camino que sigue Mann, pero, al mismo tiempo, el escritor alemán halla en el diálogo plutarqueo todo lo necesario para construir su historia de amor masculino y decide no prescindir de él.

La mort a Venècia de Thomas Mann o la via plutarquea vers Eros

A Mort a Venècia Thomas Mann es refereix explícitament al Simposi i al Fedre de Plató per explicar la relació entre Gustav von Aschenbach i Tadzio, però amaga que la seva novel·la s'inspira també en l'Eròtic de Plutarc. Per què? L'objectiu d'aquest article és justament revelar les raons d'aquest capteniment. En efecte, Plutarc elogia l'amor matrimonial a l'Eròtic i aquest no és el camí que segueix Mann, però, alhora, l'escriptor alemany troba en el diàleg plutarqueu tot el que necessita per bastir la seva història d'amor masculí i decideix no prescindir-ne.

Billy Budd: de H. Melville a E. M. Forster, o la via Plutarquea vers Plató

L'objectiu d'aquest article és proposar i fonamentar una via plutarquea -no només Les Vides Paral·leles, sinó també L'Eròtic- vers el contingut platònic de Billy Budd de B. Britten amb libretto d'E. M. Fosrter en col·laboració amb Eric Crozier. H. Melville no cita pas Plutarc en la seva novel·la, però l'excel·lent coneixement dels textos de l'escriptor i filòsof grec per part d'E. M. Foster fa que aquesta hipòtesi sigui altament versemblant.

Billy Budd: de H. Melville a E. M. Forster, o la via Plutarquea hacia Platón

El objetivo de este artículo es proponer y fundamentar una vía plutarquea -no sólo Las Vidas Parelelas, sino tambén El Eròtico- al contenido platónico de Billy Budd de B. Britten con libreto de E. M. Foster en colaboración con Eric Crozier. H. Melville no cita a Plutarco en su novela, pero el excelente conocimiento de los textos del escritor y filósofo griego por parte de E. M. Forster hace que esta hipótesis sea altamente verosímil.

Discretized integral hydrodynamics

Using an interpolant form for the gradient of a function of position, we write an integral version of the conservation equations for a fluid. In the appropriate limit, these become the usual conservation laws of mass, momentum, and energy. We also discuss the special cases of the Navier-Stokes equations for viscous flow and the Fourier law for thermal conduction in the presence of hydrodynamic fluctuations. By means of a discretization procedure, we show how the integral equations can give rise to the so-called particle dynamics of smoothed particle hydrodynamics and dissipative particle dynamics.

In vitro antitumor activity of methotrexate via pH-sensitive chitosan nanoparticles

Nanoparticles with pH-sensitive behavior may enhance the success of chemotherapy in many cancers by efficient intracellular drug delivery. Here, we investigated the effect of a bioactive surfactant with pH-sensitive properties on the antitumor activity and intracellular behavior of methotrexate-loaded chitosan nanoparticles (MTX-CS-NPs). NPs were prepared using a modified ionotropic complexation process, in which was included the surfactant derived from Nα,Nε-dioctanoyl lysine with an inorganic lithium counterion. The pH-sensitive behavior of NPs allowed accelerated release of MTX in an acidic medium, as well as membrane-lytic pH-dependent activity, which facilitated the cytosolic delivery of endocytosed materials. Moreover, our results clearly proved that MTX-CSNPs were more active against the tumor HeLa and MCF-7 cell lines than the free drug. The feasibilty of using NPs to target acidic tumor extracellular pH was also shown, as cytotoxicity against cancer cells was greater in a mildly acidic environment. Finally, the combined physicochemical and pH-sensitive properties of NPs generally allowed the entrapped drug to induce greater cell cycle arrest and apoptotic effects. Therefore, our overall results suggest that pH-sensitive MTX-CS-NPs could be potentially useful as a carrier system for tumor and intracellular drug delivery in cancer therapy.