New topologies in pentanuclear nickel/oximato clusters: structural and magnetic characterization

In the present work, five new Ni5 clusters employing the versatile 2-pyridylcyanoxime ligand have been synthesized and chemically, structurally, and magnetically characterized. The crystallographic examination of these Ni5 clusters together with those already published in the literature, giving a total number of 14 complexes, exhibiting up to 8 different topologies for which the relationship between topology, reaction conditions and magnetic response has been analyzed. DC magnetic measurements were carried in the 300-2 K range for the new complexes and the analysis of the experimental data revealed an antiferromagnetic response for the oximato mediated interactions with a variety of ground states (S = 0, 1, 3) as function of the cluster topology

Systemic profiles of micrornas, redox balance, and inflammation in lung cancer patients : influence of copd

Altres ajuts: This study has been supported by Spanish Ministry of Science and Innovation, Sociedad Española de Neumología y Cirugía Torácica (SEPAR) 2018 & 2020.Lung cancer (LC) risk increases in patients with chronic respiratory diseases (COPD). MicroRNAs and redox imbalance are involved in lung tumorigenesis in COPD patients. Whether systemic alterations of those events may also take place in LC patients remains unknown. Our objectives were to assess the plasma levels of microRNAs, redox balance, and cytokines in LC patients with/without COPD. MicroRNAs (RT-PCR) involved in LC, oxidized DNA, MDA-protein adducts, GSH, TEAC, VEGF, and TGF-beta (ELISA) were quantified in plasma samples from non-LC controls (n = 45), LC-only patients (n = 32), and LC-COPD patients (n = 91). In LC-COPD patients compared to controls and LC-only, MDA-protein adduct levels increased, while those of GSH decreased, and two patterns of plasma microRNA were detected. In both LC patient groups, miR-451 expression was downregulated, while those of microRNA-let7c were upregulated, and levels of TEAC and TGF-beta increased compared to the controls. Correlations were found between clinical and biological variables. A differential expression profile of microRNAs was detected in patients with LC. Moreover, in LC patients with COPD, plasma oxidative stress levels increased, whereas those of GSH declined. Systemic oxidative and antioxidant markers are differentially expressed in LC patients with respiratory diseases, thus implying its contribution to the pathogenesis of tumorigenesis in these patients

Novetats en el diagnòstic de lesions tumorals al pulmó

S'ha publicat un estudi sobre l'ús d'una nova tecnologia mínimament invasiva en el diagnòstic de lesions tumorals al pulmó, l'ultrasonografia endobronquial (USEB), que consisteix en una minisonda ecogràfica que s'introdueix pel canal de treball del broncofibroscopi i pot accedir a les ramificacions bronquials per localitzar una lesió tumoral. Els resultats mostren que el rendiment diagnòstic d'utilitzar conjuntament aquest procediment i la fluoroscòpia (radiologia) és més elevat que l'ús de la fluoroscòpia únicament.Se ha publicado un estudio sobre el uso de una nueva tecnología mínimamente invasiva en el diagnóstico de lesiones tumorales en el pulmón, la ultrasonografía endobronquial (USEB), que consiste en una minisonda ecográfica que se introduce por el canal de trabajo del fibrobroncoscopio y puede acceder a las ramificaciones bronquiales para localizar una lesión tumoral. Los resultados muestran que el rendimiento diagnóstico de utilizar conjuntamente este procedimiento y la fluoroscopia (radiología) es más elevado que el uso de la fluoroscopia únicamente

Implementation of the Random Forest Method for the Imaging Atmospheric Cherenkov Telescope MAGIC

The paper describes an application of the tree classification method Random Forest (RF), as used in the analysis of data from the ground-based gamma telescope MAGIC. In such telescopes, cosmic gamma-rays are observed and have to be discriminated against a dominating background of hadronic cosmic-ray particles. We describe the application of RF for this gamma/hadron separation. The RF method often shows superior performance in comparison with traditional semi-empirical techniques. Critical issues of the method and its implementation are discussed. An application of the RF method for estimation of a continuous parameter from related variables, rather than discrete classes, is also discussed.Comment: 16 pages, 8 figure

Simultaneous multi-frequency observation of the unknown redshift blazar PG 1553+113 in March-April 2008

The blazar PG 1553+113 is a well known TeV gamma-ray emitter. In this paper, we determine its spectral energy distribution using simultaneous multi-frequency data in order to study its emission processes. An extensive campaign was carried out between March and April 2008, where optical, X-ray, high-energy (HE) gamma-ray, and very-high-energy (VHE) gamma-ray data were obtained with the KVA, Abastumani, REM, RossiXTE/ASM, AGILE and MAGIC telescopes, respectively. This is the first simultaneous broad-band (i.e., HE+VHE) gamma-ray observation, though AGILE did not detect the source. We combine data to derive source's spectral energy distribution and interpret its double peaked shape within the framework of a synchrotron self compton modelComment: 5 pages, 2 figures, publishe

Upper limit for gamma-ray emission above 140 GeV from the dwarf spheroidal galaxy Draco

The nearby dwarf spheroidal galaxy Draco with its high mass to light ratio is one of the most auspicious targets for indirect dark matter searches. Annihilation of hypothetical DM particles can result in high-energy gamma-rays, e.g. from neutralino annihilation in the supersymmetric framework. With the MAGIC telescope a search for a possible DM signal originating from Draco was performed during 2007. The analysis of the data results in a flux upper limit of 1.1x10^-11 photons cm^-2 sec^-1 for photon energies above 140 GeV, assuming a point like source. Furthermore, a comparison with predictions from supersymmetric models is given. While our results do not constrain the mSUGRA phase parameter space, a very high flux enhancement can be ruled out.Comment: Accepted for publication by Astrophysical Journa

Unfolding of differential energy spectra in the MAGIC experiment

The paper describes the different methods, used in the MAGIC experiment, to unfold experimental energy distributions of cosmic ray particles (gamma-rays). Questions and problems related to the unfolding are discussed. Various procedures are proposed which can help to make the unfolding robust and reliable. The different methods and procedures are implemented in the MAGIC software and are used in most of the analyses.Comment: Submitted to NIM

Systematic search for VHE gamma-ray emission from X-ray bright high-frequency BL Lac objects

All but three (M87, BL Lac and 3C 279) extragalactic sources detected so far at very high energy (VHE) gamma-rays belong to the class of high-frequency peaked BL Lac (HBL) objects. This suggested to us a systematic scan of candidate sources with the MAGIC telescope, based on the compilation of X-ray blazars by Donato et al. (2001). The observations took place from December 2004 to March 2006 and cover sources on the northern sky visible under small zenith distances zd < 30 degrees at culmination. The sensitivity of the search was planned for detecting X-ray bright F(1 keV) > 2 uJy) sources emitting at least the same energy flux at 200 GeV as at 1 keV. In order to avoid strong gamma-ray attenuation close to the energy threshold, the redshift of the sources was constrained to values z<0.3. Of the fourteen sources observed, 1ES 1218+304 and 1ES 2344+514 have been detected in addition to the known bright TeV blazars Mrk 421 and Mrk 501. A marginal excess of 3.5 sigma from the position of 1ES 1011+496 was observed and has been confirmed as a source of VHE gamma-rays by a second MAGIC observation triggered by a high optical state (Albert et al. 2007). For the remaining sources, we present here the 99% confidence level upper limits on the integral flux above ~200 GeV. We characterize the sample of HBLs (including all HBLs detected at VHE so far) by looking for correlations between their multi-frequency spectral indices determined from simultaneous optical, archival X-ray, and radio luminosities, finding that the VHE emitting HBLs do not seem to constitute a unique subclass. The absorption corrected gamma-ray luminosities at 200 GeV of the HBLs are generally not higher than their X-ray luminosities at 1 keV.Comment: 15 pages, 7 figures, 5 tables, submitted to ApJ (revised version

MAGIC Upper Limits for two Milagro-detected, Bright Fermi Sources in the Region of SNR G65.1+0.6

We report on the observation of the region around supernova remnant G65.1+0.6 with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV gamma-ray sources 1FGL J1954.3+2836 and 1FGL J1958.6+2845. They are identified as GeV pulsars and both have a possible counterpart detected at about 35 TeV by the Milagro observatory. MAGIC collected 25.5 hours of good quality data, and found no significant emission in the range around 1 TeV. We therefore report differential flux upper limits, assuming the emission to be point-like (<0.1 deg) or within a radius of 0.3 deg. In the point-like scenario, the flux limits around 1 TeV are at the level of 3 % and 2 % of the Crab Nebula flux, for the two sources respectively. This implies that the Milagro emission is either extended over a much larger area than our point spread function, or it must be peaked at energies beyond 1 TeV, resulting in a photon index harder than 2.2 in the TeV band.Comment: 8 pages, 3 figures, 1 tabl

Discovery of Very High Energy gamma-rays from 1ES 1011+496 at z=0.212

We report on the discovery of Very High Energy (VHE) gamma-ray emission from the BL Lacertae object 1ES1011+496. The observation was triggered by an optical outburst in March 2007 and the source was observed with the MAGIC telescope from March to May 2007. Observing for 18.7 hr we find an excess of 6.2 sigma with an integrated flux above 200 GeV of (1.58$\pm0.32) 10^{-11}$ photons cm$^{-2}$ s$^{-1}$. The VHE gamma-ray flux is >40% higher than in March-April 2006 (reported elsewhere), indicating that the VHE emission state may be related to the optical emission state. We have also determined the redshift of 1ES1011+496 based on an optical spectrum that reveals the absorption lines of the host galaxy. The redshift of z=0.212 makes 1ES1011+496 the most distant source observed to emit VHE gamma-rays up to date.Comment: 4 pages, 6 figures, minor changes to fit the ApJ versio