Near-arcsecond resolution observations of the hot corino of the solar type protostar IRAS 16293-2422

Complex organic molecules have previously been discovered in solar type protostars, raising the questions of where and how they form in the envelope. Possible formation mechanisms include grain mantle evaporation, interaction of the outflow with its surroundings or the impact of UV/X-rays inside the cavities. In this Letter we present the first interferometric observations of two complex molecules, CH3CN and HCOOCH3, towards the solar type protostar IRAS16293-2422. The images show that the emission originates from two compact regions centered on the two components of the binary system. We discuss how these results favor the grain mantle evaporation scenario and we investigate the implications of these observations for the chemical composition and physical and dynamical state of the two components.Comment: 5 pages (apjemulate), 2 figures; accepted by ApJ

Toll-like receptor-mediated signaling cascade as a regulator of the inflammation network during alcoholic liver disease

Chronic abuse of alcohol leads to various histological abnormalities in the liver. These are conditions collectively known as alcoholic liver disease (ALD). Currently, ALD is considered to be one of the major causes of death worldwide. An impaired intestinal barrier with related endotoxemia is among the various pathogenetic factors. This is mainly characterized by circulating levels of lipopolysaccharide (LPS), considered critical for the onset of intra-hepatic inflammation. This in turn promotes hepatocellular damage and fibrosis in ALD. Elevated levels of LPS exert their effects by binding to Toll-like receptors (TLRs) which are expressed by all liver-resident cells. The activation of TLR signaling triggers an overproduction and release of some cytokines, which promote an autocatalytic cascade of other proinflammatory signals. In this review, we provide an overview of the mechanisms that sustain LPS-mediated activation of TLR signaling, reporting current experimental and clinical evidence of its role during inflammation in ALD

Scaling behaviour of trapped bosonic particles in two dimensions at finite temperature

In the framework of the trap-size scaling theory, we study the scaling properties of the Bose-Hubbard model in two dimensions in the presence of a trapping potential at finite temperature. In particular, we provide results for the particle density and the density-density correlator at the Mott transitions and within the superfluid phase. For the former quantity, numerical outcomes are also extensively compared to Local Density Approximation predictions.Comment: 8 pages, 9 figure

Temperature dependent polariton emission from strongly coupled organic semiconductor microcavities

We investigated the absorption and photoluminescence (PL) of J-aggregates of a cyanine dye both in a thin film format and when used as the active layer in a strongly-coupled microcavity. We show that as temperature is reduced, the absorption linewidth of the J-aggregates narrows and shifts to higher energy. When the J-aggregate is placed in a microcavity we find that the energy of the polariton modes also shifts to higher energies as temperature is reduced. We compare the intensity of PL emission from the upper and lower branches at resonance as a function of temperature, and find that it can be described by an activation energy of 25 meV. PL emission spectra at resonance also suggest that uncoupled excitons inside the microcavity populate the upper polariton branch states

The solar type protostar IRAS16293-2422: new constraints on the physical structure

Context: The low mass protostar IRAS16293-2422 is a prototype Class 0 source with respect to the studies of the chemical structure during the initial phases of life of Solar type stars. Aims: In order to derive an accurate chemical structure, a precise determination of the source physical structure is required. The scope of the present work is the derivation of the structure of IRAS16293-2422. Methods: We have re-analyzed all available continuum data (single dish and interferometric, from millimeter to MIR) to derive accurate density and dust temperature profiles. Using ISO observations of water, we have also reconstructed the gas temperature profile. Results: Our analysis shows that the envelope surrounding IRAS16293-2422 is well described by the Shu "inside-out" collapsing envelope model or a single power-law density profile with index equal to 1.8. In contrast to some previous studies, our analysis does not show evidence of a large (>/- 800 AU in diameter) cavity. Conclusions: Although IRAS16293-2422 is a multiple system composed by two or three objects, our reconstruction will be useful to derive the chemical structure of the large cold envelope surrounding these objects and the warm component, treated here as a single source, from single-dish observations of molecular emission

Interplay between temperature and trap effects in one-dimensional lattice systems of bosonic particles

We investigate the interplay of temperature and trap effects in cold particle systems at their quantum critical regime, such as cold bosonic atoms in optical lattices at the transitions between Mott-insulator and superfluid phases. The theoretical framework is provided by the one-dimensional Bose-Hubbard model in the presence of an external trapping potential, and the trap-size scaling theory describing the large trap-size behavior at a quantum critical point. We present numerical results for the low-temperature behavior of the particle density and the density-density correlation function at the Mott transitions, and within the gapless superfluid phase.Comment: 9 page

A variational piecewise smooth model for identification of chromosomal imbalances in cancer

Monitoring of changes at the DNA level enables the characterization of the underlying structure of genetic diseases. In particular, copy number alterations (CNAs) are increasingly being recognized as an important component of genetic variations in cancer: oncogenes may be enhanced by DNA amplification and tumor suppressor genes may be inactivated by physical deletion. Encouraged by the advent of array comparative genomic hybridization technology, several biological studies have been designed to look for chromosomal aberrations involved in cancer. Hence, the development of algorithms aimed at the identification of CNAs is a current challenge in bioinformatics. Despite the amount of proposed approaches, identification of CNAs is yet an open problem. Here we propose a new approach for detection of CNAs that extends a previously published algorithm where a popular image segmentation variational model was used. The proposed algorithm, called Vega Multi-Channel (VegaMC), starts from the assumption that copy number profiles are piecewise constant and finds the optimal segmentation by minimizing a functional energy that represents a compromise between accuracy and parsimony of the boundaries. We applied VegaMC on a published gastrointestinal stromal tumor aCGH dataset, showing the ability of the proposed approach in the identification of well-known cytogenetic mutations, and eventually discover new ones

Water emission in NGC1333-IRAS4: The physical structure of the envelope

We report ISO-LWS far infrared observations of CO, water and oxygen lines towards the protobinary system IRAS4 in the NGC1333 cloud. We detected several water, OH, CO rotational lines, and two [OI] and [CII] fine structure lines. Given the relatively poor spectral and spatial resolution of these observations, assessing the origin of the observed emission is not straightforward. In this paper, we focus on the water line emission and explore the hypothesis that it originates in the envelopes that surround the two protostars, IRAS4 A and B, thanks to an accurate model. The model reproduces quite well the observed water line fluxes, predicting a density profile, mass accretion rate, central mass, and water abundance profile in agreement with previous works. We hence conclude that the emission from the envelopes is a viable explanation for the observed water emission, although we cannot totally rule out the alternative that the observed water emission originates in the outflow