830 research outputs found
Estudio de la biocompatibilidad in vitro de formulaciones acrílicas autocurables portadoras de bisfosfonatos de nueva síntesis
En este trabajo se presenta el estudio de la biocompatibilidad in vitro, empleando cultivos celulares de fibroblastos embrionarios humanos, de tres sistemas acrílicos de liberación controlada de bisfosfonatos (BFs). Estos sistemas, basados en metacrilato de metilo (MMA), metacrilato de vitamina E (MVE) y trietilenglicol dimetacrilato (TEGDMA), han sido diseñados para su aplicación en el tratamiento de enfermedades caracterizadas por una elevada resorción osteoclástica. En su preparación se ha empleado un BP comercializado (alendronato; ALN) y dos de nueva síntesis, pertenecientes a la segunda y tercera generaciones, el ácido 1-hidroxi-2-[4-aminofenil]etano-1,1-difosfónico (APBP) y el ácido 1-hidroxi-2-[3-indolil]etano-1,1-difosfónico (IBP), respectivamente. La citotoxicidad de MVE ha sido notablemente inferior a la medida para TEGDMA. La citotoxicidad de APBP e IBP se ha comparado con la de ALN, obteniéndose unos valores para la concentración IC50, de15,56, 9,86 y 6,25 mmol/l para APBP, ALN e IBP, respectivamente. Los niveles de citotoxicidad liberada han sido superiores para la formulación portadora de ALN, situándose a continuación los cementos cargados con IBP y APBP. Cuando los cultivos se han establecido sobre la superficie de las formulaciones, se han detectado unos niveles de proliferación celular y adhesión superiores para los sistemas de liberación de IBP y APBP, siendo además inferior en estos casos la mortalidad celular.This paper reports the in vitro biocompatibility study, using human embryonic fibroblast cultures, of three acrylic systems for controlled release of bisphosphonates (BFs). These systems, that are based on methyl methacrylate (MMA), vitamin E methacrylate (MVE) and triethyleneglycol dimethacrylate (TEGDMA), have been designed for its application in the treatment of pathologies characterized by a high osteoclastic resorption. A commercial BP (alendronate; ALN) and two novel BPs, belonging to the second and third generations, 1-hydroxy-2-[4-aminophenyl]ethane-1,1-diphosphonic acid (APBP) and 1-hydroxy-2-[3-indolyl]ethane-1,1-diphosphonic acid (IBP), respectively, have been used in their preparation. The cytotoxicity of MVE has been notably lower than that measured for TEGDMA. Cytotoxicity of APBP and IBP was evaluated along with that of ALN, and the following values of the IC50, concentration were obtained for APBP, ALN and IBP respectively: 15.56, 9.86 and 6.25 mmol/l. The cytotoxicity levels obtained from the extracts of the cured systems were higher for the formulation containing ALN, followed by the cements loaded with IBP and APBP. When the cultures were seeded directly on the formulations surface, higher levels of cellular proliferation and adhesion were obtained for the systems containing IBP and APBP, the cellular mortality being also inferior in these cases
Xylotrechus arvicola (Olivier) (Coleoptera, Cerambycidae), a new impacting pest on Spanish vineyards
Research NoteInfestation caused by Xylotrechus arvicola (Olivier) (Coleoptera, Cerambycidae) is becoming a new sanitary problem in some Spanish vine-producing areas. Symptoms caused by the pest, the identification of 7 associated wood fungal species living in galleries excavated by larvae, some data about the evolution of the infestation during 8 years in the same plot and the different levels of susceptibility exhibited by three grape varieties are presented in this paper
Central star formation and metallicity in CALIFA interacting galaxies
We use optical integral-field spectroscopic (IFS) data from 103 nearby
galaxies at different stages of the merging event, from close pairs to merger
remnants provided by the CALIFA survey, to study the impact of the interaction
in the specific star formation and oxygen abundance on different galactic
scales. To disentangle the effect of the interaction and merger from internal
processes, we compared our results with a control sample of 80 non-interacting
galaxies. We confirm the moderate enhancement (2-3 times) of specific star
formation for interacting galaxies in central regions as reported by previous
studies; however, the specific star formation is comparable when observed in
extended regions. We find that control and interacting star-forming galaxies
have similar oxygen abundances in their central regions, when normalized to
their stellar masses. Oxygen abundances of these interacting galaxies seem to
decrease compared to the control objects at the large aperture sizes measured
in effective radius. Although the enhancement in central star formation and
lower metallicities for interacting galaxies have been attributed to tidally
induced inflows, our results suggest that other processes such as stellar
feedback can contribute to the metal enrichment in interacting galaxies.Comment: 9 pages, 9 figures. Accepted for publication in Astronomy &
Astrophysic
Recent evolution and associated hydrological dynamics of a vanishing tropical Andean glacier: Glaciar de Conejeras, Colombia
Glaciers in the inner tropics are rapidly retreating due to atmospheric
warming. In Colombia, this retreat is accelerated by volcanic activity, and
most glaciers are in their last stages of existence. There is general
concern about the hydrological implications of receding glaciers, as they
constitute important freshwater reservoirs and, after an initial increase in
melting flows due to glacier retreat, a decrease in water resources is
expected in the long term as glaciers become smaller. In this paper, we
perform a comprehensive study of the evolution of a small Colombian glacier,
Conejeras (Parque Nacional Natural de los Nevados) that has been monitored
since 2006, with a special focus on the hydrological response of the
glacierized catchment. The glacier shows great sensitivity to changes in
temperature and especially to the evolution of the El Niño–Southern
Oscillation (ENSO) phenomenon, with great loss of mass and area during El
Niño warm events. Since 2006, it has suffered a 37 % reduction, from
22.45 ha in 2006 to 12 ha in 2017, with an especially abrupt reduction since
2014. During the period of hydrological monitoring (June 2013 to December 2017),
streamflow at the outlet of the catchment experienced a noticeable
cycle of increasing flows up to mid-2016 and decreasing flows afterwards.
The same cycle was observed for other hydrological indicators, including the
slope of the rising flow limb and the monthly variability of flows. We
observed an evident change in the daily hydrograph, from a predominance of
days with a purely melt-driven hydrograph up to mid-2016, to an increase in
the frequency of days with flows less influenced by melt after 2016. Such a
hydrological cycle is not directly related to fluctuations of temperature or
precipitation; therefore, it is reasonable to consider that it is the
response of the glacierized catchment to retreat of the glacier. Results
confirm the necessity for small-scale studies at a high temporal resolution,
in order to understand the hydrological response of glacier-covered
catchments to glacier retreat and imminent glacier extinction.</p
Insights on the stellar mass-metallicity relation from the CALIFA survey
We use spatially and temporally resolved maps of stellar population
properties of 300 galaxies from the CALIFA integral field survey to investigate
how the stellar metallicity (Z*) relates to the total stellar mass (M*) and the
local mass surface density (*) in both spheroidal and disk dominated
galaxies. The galaxies are shown to follow a clear stellar mass-metallicity
relation (MZR) over the whole 10 to 10 M range. This
relation is steeper than the one derived from nebular abundances, which is
similar to the flatter stellar MZR derived when we consider only young stars.
We also find a strong relation between the local values of * and Z* (the
ZR), betraying the influence of local factors in determining Z*. This
shows that both local (*-driven) and global (M*-driven) processes are
important in determining the metallicity in galaxies. We find that the overall
balance between local and global effects varies with the location within a
galaxy. In disks, * regulates Z*, producing a strong ZR whose
amplitude is modulated by M*. In spheroids it is M* who dominates the physics
of star formation and chemical enrichment, with * playing a minor,
secondary role. These findings agree with our previous analysis of the star
formation histories of CALIFA galaxies, which showed that mean stellar ages are
mainly governed by surface density in galaxy disks and by total mass in
spheroids.Comment: 6 pages, 3 figures, accepted for publication in ApJ
Ionized gas kinematics of galaxies in the CALIFA survey : I. Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems
J.M.A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild). Date of Acceptance: 01/08/2014Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims. The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. Methods. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component for each spectrum in the CALIFA data cubes for different emission lines (namely, [O ii] λλ3726,3729, [O iii] λλ4959,5007, Hα+[N ii] λλ6548,6584, and [SII]λλ6716,6730). The main kinematic parameters measured on the plane of the sky were directly derived from the radial velocities with no assumptions on the internal prevailing motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [O iii] λλ4959,5007 emission line profiles. Results. At the velocity resolution of CALIFA, most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. Thirty-five percent of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity (AGN or LINER). Early-type (E+S0) galaxies in the sample present clear photometric-kinematic misaligments. There is evidence of asymmetries in the emission line profiles in 117 out of the 177 analyzed galaxies, suggesting the presence of kinematically distinct gaseous components located at different distances from the optical nucleus. The kinematic decoupling between the dominant and secondary component/s suggested by the observed asymmetries in the profiles can be characterized by a limited set of parameters. Conclusions. This work constitutes the first determination of the ionized gas kinematics of the galaxies observed in the CALIFA survey. The derived velocity fields, the reported kinematic distortions/peculiarities and the identification of the presence of several gaseous components in different regions of the objects might be used as additional criteria for selecting galaxies for specific studies.Publisher PDFPeer reviewe
Occurrence of organotin compounds in waters of the spanish coast under the European Water Framework Directive
Organotin compounds (OTCs), such as tributyltin (TBT), are persistent organic pollutants that are
present in water samples (surface water, river water, sea water, waste water, etc.) because of
anthropogenic activities (antifouling agents in ship paints, biocides in polymers, etc.). The toxicity
and endocrine disruption potential of these chemicals have been demonstrated even at very low
levels (<1 ng L−1) (Devos et al. 2012). Due to the extensive presence of OTCs in all environmental
media as well as their adverse effects on human health and biota, quantitative and qualitative
determination of those com-pounds in complex environmental matrices has become a matter of
great concern, mainly butyl and phenyl-substituted. Also, these compounds are included in the list of
priority substances according to the EU Directive 2013/39/EU amending Directives 2000/60/EC and
2008/105/EC as regards priority substances in the field of water policy. This directive specifies
annual average environmental quality standard (AA-EQS) of 0.2 ng L−1 TBT and a maximum
allowable environmental quality standard (MAC-EQS) of 1.5 ng L−1 TBT for all surface waters.
Samples were collected in two semiconfined coastal areas, one of them an area with high industrial
and port activities (Ría de Vigo) and the other one with high touristic and agricultural activity (Mar
Menor).The sampling campaigns were performed in spring and autumn of 2015. The levels of MBT,
DBT, TBT, MPhT, DPhT and TPhT in the seawater samples were analyzed by HS-SPME-GC–QqQMS/
MS method (Moscoso-Pérez et al. 2015).
MPhT, DPhT and TPhT were not detected in any sample at levels higher than LOQ. For butylated
compounds, MBT, DBT and TBT were detected in 100% of the analyzed samples in the Mar Menor.
In the Vigo estuary, MBT has been detected in 83.3% of the samples, the DBT in 75% and the TBT
in 88%. The TBT is present in 92% of the total of 39 analyzed samples, being detected in 100% of
the samples of the Mar Menor and in 88% of the samples of the Ría de Vigo. These levels are
similar than those detected in other locations, and lower than the detected in ports near the coast of
Gijón characterized by a great maritime traffic (Centineo et al. 2004).Program of Consolidation and Structuring of Units of Competitive Investigation of the University System of Galicia (Xunta de Galicia) potentially cofinanced by ERDF in the frame of the operative Program of Galicia 2007-2013 (reference: GRC2013-047) and by the Ministry of Economy and Competitiveness (IMPACTA, project reference: CTM2013-48194-C3-2-R, and ARPA-ACUA, project reference: CTM2016-77945-C3-3-R)
Expression of NS1 and NS2-Nt (NS21-180) by ChAdOx1 and MVA confers protection in sheep against bluetongue
The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and Te-based literature data
The use of IFS is since recently allowing to measure the emission line fluxes
of an increasingly large number of star-forming galaxies both locally and at
high redshift. The main goal of this study is to review the most widely used
empirical oxygen calibrations, O3N2 and N2, by using new direct abundance
measurements. We pay special attention to the expected uncertainty of these
calibrations as a function of the index value or abundance derived and the
presence of possible systematic offsets. This is possible thanks to the
analysis of the most ambitious compilation of Te-based HII regions to date.
This new dataset compiles the Te-based abundances of 603 HII regions extracted
from the literature but also includes new measurements from the CALIFA survey.
Besides providing new and improved empirical calibrations for the gas
abundance, we also present here a comparison between our revisited calibrations
with a total of 3423 additional CALIFA HII complexes with abundances derived
using the ONS calibration by Pilyugin et al. (2010). The combined analysis of
Te-based and ONS abundances allows us to derive their most accurate calibration
to date for both the O3N2 and N2 single-ratio indicators, in terms of all
statistical significance, quality and coverage of the space of parameters. In
particular, we infer that these indicators show shallower abundance
dependencies and statistically-significant offsets compared to those of Pettini
and Pagel (2004), Nagao et al. (2006) and P\'erez-Montero and Contini (2009).
The O3N2 and N2 indicators can be empirically applied to derive oxygen
abundances calibrations from either direct abundance determinations with random
errors of 0.18 and 0.16, respectively, or from indirect ones (but based on a
large amount of data) reaching an average precision of 0.08 and 0.09 dex
(random) and 0.02 and 0.08 dex (systematic; compared to the direct
estimations),respectively.Comment: 12 pages, 5 figures, accepted for publication in A&
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