2005-2017 Ozone trends and potential benefits of local measures as deduced from air quality measurements in the north of the Barcelona metropolitan area

We analyzed 2005–2017 data sets on ozone (O3) concentrations in an area (the Vic Plain) frequently affected by the atmospheric plume northward transport of the Barcelona metropolitan area (BMA), the atmospheric basin of Spain recording the highest number of exceedances of the hourly O3 information threshold (180¿µg¿m-3). We aimed at evaluating the potential benefits of implementing local-BMA short-term measures to abate emissions of precursors. To this end, we analyzed in detail spatial and time variations of concentration of O3 and nitrogen oxides (NO and NO2, including OMI remote sensing data for the latter). Subsequently, a sensitivity analysis is done with the air quality (AQ) data to evaluate potential O3 reductions in the north of the BMA on Sundays compared with weekdays as a consequence of the reduction in regional emissions of precursors. The results showed a generalized decreasing trend for regional background O3 as well as the well-known increase in urban O3 and higher urban NO decreasing slopes compared with those of NO2. The most intensive O3 episodes in the Vic Plain are caused by (i) a relatively high regional background O3 (due to a mix of continental, hemispheric–tropospheric and stratospheric contributions); by (ii) intensive surface fumigation from mid-troposphere high O3 upper layers arising from the concatenation of the vertical recirculation of air masses; but also by (iii) an important O3 contribution from the northward transport/channeling of the pollution plume from the BMA. The high relevance of the local-daily O3 contribution during the most intense pollution episodes is clearly supported by the O3 (surface concentration) and NO2 (OMI data) data analysis. A maximum decrease potential (by applying short-term measures to abate emissions of O3 precursors) of 49¿µg¿O3¿m-3 (32¿%) of the average diurnal concentrations was determined. Structurally implemented measures, instead of episodically, could result in important additional O3 decreases because not only the local O3 coming from the BMA plume would be reduced, but also the recirculated O3 and thus the intensity of O3 fumigation in the plain. Therefore, it is highly probable that both structural and episodic measures to abate NOx and volatile organic compound (VOC) emissions in the BMA would result in evident reductions of O3 in the Vic PlainPeer ReviewedPostprint (author's final draft

Gold Nanosystems Covered with Doxorubicin/DNA Complexes: A Therapeutic Target for Prostate and Liver Cancer

Different gold nanosystems covered with DNA and doxorubicin (Doxo) were designed and synthesized for cancer therapy, starting from Au@16-Ph-16 cationic nanoparticles and DNA–Doxo complexes prepared under saturation conditions. For the preparation of stable, biocompatible, and small-sized compacted Au@16-Ph-16/DNA–Doxo nanotransporters, the conditions for the DNA–Doxo compaction process induced by gold nanoparticles were first explored using fluorescence spectroscopy, circular dichroism and atomic force microscopy techniques. The reverse process, which is fundamental for Doxo liberation at the site of action, was found to occur at higher CAu@16-Ph-16 concentrations using these techniques. Zeta potential, dynamic light scattering and UV–visible spectroscopy reveal that the prepared compacted nanosystems are stable, highly charged and of adequate size for the effective delivery of Doxo to the cell. This fact is verified by in vitro biocompatibility and internalization studies using two prostate cancer-derived cell lines (LNCaP and DU145) and one hepatocellular carcinoma-derived cell line (SNU-387), as well as a non-tumor prostate (PNT2) cell line and a non-hepatocarcinoma hepatoblastoma cell line (Hep-G2) model used as a control in liver cells. However, the most outstanding results of this work are derived from the use of the CI+NI combined treatments which present strong action in cancer-derived cell lines, while a protective effect is observed in non-tumor cell lines. Hence, novel therapeutic targets based on gold nanoparticles denote high selectivity compared to conventional treatment based on free Doxo at the same concentration. The results obtained show the viability of both the proposed methodology for internalization of compacted nanocomplexes inside the cell and the effectiveness of the possible treatment and minimization of side effects in prostate and liver cancer

Unveiling the monster heart: unbeamed properties of blazar 4C 71.07

4C 71.07 is a high-redshift blazar whose optical radiation is dominated by quasar-like nuclear emission. We here present the results of a spectroscopic monitoring of the source to study its unbeamed properties. We obtained 24 optical spectra at the Nordic Optical Telescope (NOT) and William Herschel Telescope (WHT) and 3 near-infrared spectra at the Telescopio Nazionale Galileo (TNG). They show no evidence of narrow emission lines. The estimate of the systemic redshift from the H$\beta$ and H$\alpha$ broad emission lines leads to $z_{\rm sys}=2.2130 \pm 0.0004$. Notwithstanding the nearly face-on orientation of the accretion disc, the high-ionization emission lines present large broadening as well as noticeable blueshifts, which increase with the ionizing energy of the corresponding species. This is a clear indication of strong ionized outflows. Line broadening and blueshift appear correlated. We applied scaling relationships to estimate the mass of the supermassive black hole from the Balmer and C IV lines, taking into account the prescriptions to correct for outflow. They give $M_{\rm BH} \sim 2 \times 10^9 \, M_\odot$. We derived an Eddington luminosity $L_{\rm Edd} \sim 2.5 \times 10^{47} \rm \, erg \, s^{-1}$ $\sim L_{\rm disc}$, and a broad line region luminosity $L_{\rm BLR} \sim 1.5 \times 10^{46} \rm \, erg \, s^{-1}$. The line fluxes do not show significant variability in time. In particular, there is no line reaction to the jet flaring activity detected in 2015 October and November. This implies that the jet gives no contribution to the photoionization of the broad line region in the considered period.Comment: 13 pages, 13 figures, in press for MNRA

Exploring the circumstellar environment of the young eruptive star V2492 Cyg

Context. V2492 Cyg is a young eruptive star that went into outburst in 2010. The near-infrared color changes observed since the outburst peak suggest that the source belongs to a newly defined sub-class of young eruptive stars, where time-dependent accretion and variable line-of-sight extinction play a combined role in the flux changes. Aims. In order to learn about the origin of the light variations and to explore the circumstellar and interstellar environment of V2492 Cyg, we monitored the source at ten different wavelengths, between 0.55 \mu m and 2.2 \mu m from the ground and between 3.6 \mu m and 160 \mu m from space. Methods. We analyze the light curves and study the color-color diagrams via comparison with the standard reddening path. We examine the structure of the molecular cloud hosting V2492 Cyg by computing temperature and optical depth maps from the far-infrared data. Results. We find that the shapes of the light curves at different wavelengths are strictly self-similar and that the observed variability is related to a single physical process, most likely variable extinction. We suggest that the central source is episodically occulted by a dense dust cloud in the inner disk, and, based on the invariability of the far-infrared fluxes, we propose that it is a long-lived rather than a transient structure. In some respects, V2492 Cyg can be regarded as a young, embedded analog of UX Orionis-type stars. Conclusions. The example of V2492 Cyg demonstrates that the light variations of young eruptive stars are not exclusively related to changing accretion. The variability provided information on an azimuthally asymmetric structural element in the inner disk. Such an asymmetric density distribution in the terrestrial zone may also have consequences for the initial conditions of planet formation.Comment: 9 pages, 7 figures, 2 online tables, accepted for publication in A&

Type 2 diabetes mellitus and COVID-19: a narrative review

Type-2 diabetes mellitus (T2DM) is a chronic metabolic disorder. The incidence and prevalence of patients with T2DM are increasing worldwide, even reaching epidemic values in most high- and middle-income countries. T2DM could be a risk factor of developing complications in other diseases. Indeed, some studies suggest a bidirectional interaction between T2DM and COVID-19. A growing body of evidence shows that COVID-19 prognosis in individuals with T2DM is worse compared with those without. Moreover, various studies have reported the emergence of newly diagnosed patients with T2DM after SARS-CoV-2 infection. The most common treatments for T2DM may influence SARS-CoV-2 and their implication in infection is briefly discussed in this review. A better understanding of the link between TD2M and COVID-19 could proactively identify risk factors and, as a result, develop strategies to improve the prognosis for these patients

Variability and evolution of the optical polarization of a sample of gamma-ray blazars

We present a polarization variability analysis of a sample of 26 $\gamma$-ray blazars monitored by the Steward Observatory between 2008 and 2018 in the optical band. We investigate the properties and long-term variability of their optical polarization, searching for differences between blazar types. We observe that BL Lac objects are typically less polarized and less variable than flat spectrum radio quasars (FSRQs). Moreover, BL Lacs display a distribution of their polarization angle typically oriented in a preferential direction, contrary to the rather random distribution of FSRQs. For the latter blazar type, as well as those sources showing a bright stellar emission, we take into account the depolarizing effect introduced by the broad line region and the host galaxy on the measured polarization degree. In this sample we also observe that BL Lacs present an uncorrelated evolution of the flux and the polarization. Contrary, FSRQs show a correlation before the depolarization correction, that is lost however after considering this effect. In addition, we study the behaviour of the polarization angle, searching for angle rotations in its long-term evolution. We derive that the FSRQs studied here show rotations more frequently than BL Lac objects by a factor $\sim$1.5. During these periods we also observe a systematic decrease of the polarization fraction, as well as a marginal flux increase, not significant however to connect rotations with optical flares. We interpret these results within the extended shock-in-jet scenario, able to explain the overall features observed here for the polarization of the blazar sample.Comment: Accepted for publication in MNRA

Relating high ozone, ultrafine particles, and new particle formation episodes using cluster analysis

We studied the simultaneity of tropospheric ozone (O3) episodes, high ultrafine particle (UFP; diameter < 100 nm) concentrations, and the occurrence of new particle formation at a regional background station in the Western Mediterranean (northeast Spain), which is affected considerably by the transport of pollutants emitted in the Barcelona metropolitan area and nearby populated and industrial areas. Using cluster analysis, we categorized summer and spring days between 2014 and 2018 according to their daily cycles of O3 concentrations, and then studied the evolution of the particle number size distribution, meteorological variables, and black carbon and sulfur dioxide concentrations. The analysis revealed that, in spring and summer, the highest UFP concentrations coincided with the highest O3 episodes, but new particle formation was largely inhibited during these episodes, probably due to the high aerosol pollution load transported from the Barcelona metropolitan area to the station. In contrast, new particle formation episodes were concurrent with the lowest concentrations of O3 and UFPs, including the number of particles in the 9–25 nm size range. Measurements carried out in an intensive field study, using an air ion spectrometer and a particle size magnifier, support these results. In addition, measurements obtained onboard tethered balloons revealed that sea and land breezes transported regional pollutants vertically up to about 400 m above ground level. This coincided with episodes of vertical recirculation of air masses that lasted for several days, which resulted in high O3 and high UFP episodes, while new particle formation was inhibited.Peer reviewe

A New Multi-Wavelength Census of Blazars

Context:Blazars are the rarest and most powerful active galactic nuclei, playing a crucial and growing role in today multi-frequency and multi-messenger astrophysics. Current blazar catalogs, however, are incomplete and particularly depleted at low Galactic latitudes. Aims: We aim at augmenting the current blazar census to build a catalog of blazar candidates with homogeneous sky coverage that can provide candidate counterparts to unassociated gamma-ray sources, sources of high-energy neutrino emission, and ultra-high energy cosmic rays. Methods: Starting from the ALMA Calibrator Catalog we built a catalog of 1580 blazar candidates (ALMA Blazar Candidates, ABC) for which we collect multi-wavelength information. We also compared ABC sources with existing blazar catalogs. Results: The ABC catalogue fills the lack of low Galactic latitude sources in current blazar catalogues. ABC sources are significantly dimmer than known blazars in Gaia g band, and they appear bluer in SDSS and WISE colors. The majority of ABC sources (~ 90%) have optical spectra that classify them as QSO, while the remaining sources resulted galactic objects. ABC sources are similar in X-rays to known blazar, while in gamma-rays they are on average dimmer and softer, indicating a significant contribution of FSRQ sources. Making use of WISE colours, we classified 715 ABC sources as candidate gamma-ray blazar of different classes. Conclusions: We built a new catalogue of 1580 candidate blazars with a rich multi-wavelength data-set, filling the lack of low Galactic latitude sources in current blazar catalogues. This will be particularly important to identify the source population of high energy neutrinos or ultra-high energy cosmic rays. The data collected by the upcoming LSST surveys will provide a key tool to investigate the possible blazar nature of these sources.Comment: 53 pages, 32 figures, 6 tables. Accepted for publication on A&