3,336 research outputs found
Subphthalocyaninato boron(III) hydride: synthesis, structure and reactivity
Subphthalocyanine (SubPc) chemistry has been limited so far by their high sensitivity toward strong nucleophiles. In particular, the substitution of the axial chlorine atom by a nucleophilic group in the case of less-reactive SubPcs, such as those bearing electron-withdrawing peripheral substituents, presents some limitations and requires harsh conditions. By taking advantage of the electrophilic character of DIBAL-H, it has been possible to prepare for the first time SubPc-hydride derivatives that exhibit high reactivity as hydroboration reagents of aldehydes. This hydride transfer requires using a typical carbonyl activator (trimethylsilyl triflate) and only one equivalent of aldehyde, affording SubPcs with an axial benzyloxy group in good yield. This transformation has proven to be a useful alternative method for the axial functionalisation of dodecafluoroSubPc, a paradigmatic SubPc derivative, by using electrophiles for the first time. Considering the increasing interest in SubPcs as electron-acceptor semiconductors with remarkable absorption in the visible range to replace fullerene in organic photovoltaic (OPV) devices, it is of the utmost importance to develop new synthetic methodologies for their axial functionalisationFinancial support from Spanish MINECO and MICINN (CTQ2017- 85393-P, PGC2018-094644-B-C21, PDI2019-110091GB-I00) is acknowledged. IMDEA Nanociencia acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, grant SEV2016-0686). J.L. and L.T. acknowledge MECD, Spain, for a F.P.U. fellowship. I.C. and L.M
A Comparative Study of Electric Load Curve Changes in an Urban Low-Voltage Substation in Spain during the Economic Crisis (2008-2013)
This paper presents a comparative study of the electricity consumption (EC) in an urban low-voltage substation before and during the economic crisis (2008-2013). This low-voltage substation supplies electric power to near 400 users. The EC was measured for an 11-year period (2002-2012) with a sampling time of 1 minute. The study described in the paper consists of detecting the changes produced in the load curves of this substation along the time due to changes in the behaviour of consumers. The EC was compared using representative curves per time period (precrisis and crisis). These representative curves were obtained after a computational process, which was based on a search for days with similar curves to the curve of a determined (base) date. This similitude was assessed by the proximity on the calendar, day of the week, daylight time, and outdoor temperature. The last selection parameter was the error between the nearest neighbour curves and the base date curve. The obtained representative curves were linearized to determine changes in their structure (maximum and minimum consumption values, duration of the daily time slot, etc.). The results primarily indicate an increase in the EC in the night slot during the summer months in the crisis perio
New methodological approach to estimate the turbulent kinetic energy dissipation rate
The length scale and the spatio-temporal variation of turbulence intensity
has relevant implications on phytoplankton dynamics. Thus, it is important to estimate
the relevant parameters that characterize the turbulence in the water column,
such as epsilon (kinetic energy dissipation rates). One of the main objectives in this
work is the characterization of the physical dynamics at scales relevant to the biology.
Here we show different approaches to estimate the epsilon in the Alfacs Bay
(Ebre Delta), where recurrent harmful algal bloom events occur. First, we applied
the solid boundary layer theory wind velocities obtained by a nearby meteorological
station. Secondly, the gradient temperature microstructure method, based on
the Batchelor spectrum adjustment was applied on temperature data obtained by
a Self-Contained Autonomous MicroProfiler (SCAMP). These two approaches have
methodological restrictions, i.e. isotropic turbulent or the process applied to do the
Batchelor spectrum fitting.
A new method to characterize the turbulence is proposed. The velocity fields measured
by a deployed high resolution 2 MHz acoustic Doppler current profiler were
processed using the Reynolds decomposition to obtain an empirical parameter
which provides us the information about the turbulent kinetic energy in the water
column.Peer Reviewe
A fundamental plane for field star-forming galaxies
Star formation rate (SFR), metallicity and stellar mass are within the
important parameters of star--forming galaxies that characterize their
formation and evolution. They are known to be related to each other at low and
high redshift in the mass--metallicity, mass--SFR, and metallicity--SFR
relations. In this work we demonstrate the existence of a plane in the 3D space
defined by the axes SFR [log(SFR)(M_sun yr^-1)], gas metallicity [12+log(O/H)],
and stellar mass [log(M_star/M_sun)] of star-forming galaxies. We used
star--forming galaxies from the "main galaxy sample" of the Sloan Digital Sky
Survey--Data Release 7 (SDSS-DR7) in the redshift range 0.04 < z < 0.1 and
r-magnitudes between 14.5 and 17.77. Metallicities, SFRs, and stellar masses
were taken from the Max-Planck-Institute for Astrophysics-John Hopkins
University (MPA-JHU) emission line analysis database. From a final sample of
44214 galaxies, we find for the first time a fundamental plane for field
galaxies relating the SFR, gas metallicity, and stellar mass for star--forming
galaxies in the local universe. One of the applications of this plane would be
estimating stellar masses from SFR and metallicity. High redshift data from the
literature at redshift ~2.2 and 3.5, do not show evidence for evolution in this
fundamental plane.Comment: Accepted for publication in A&A. 4 pages, 4 Figures, and 2 online
figure
OTELO survey: optimal emission-line flux determination with OSIRIS/GTC
Emission-line galaxies are important targets for understanding the chemical
evolution of galaxies in the universe. Deep, narrow-band imaging surveys allow
to detect and study the flux and the equivalent widths (EW) of the emission
line studied. The present work has been developed within the context of the
OTELO project, an emission line survey using the Tunable Filters (TF) of
OSIRIS, the first generation instrument on the GTC 10.4m telescope located in
La Palma, Spain, that will observe through selected atmospheric windows
relatively free of sky emission lines. With a total survey area of 0.1 square
degrees distributed in different fields, reaching a 5 \sigma depth of 10^-18
erg/cm^2/s and detecting objects of EW < 0.3 A, OTELO will be the deepest
emission line survey to date. As part of the OTELO preparatory activities, the
objective of this study is to determine the best combination of sampling and
full width at half maximum (FWHM) for the OSIRIS tunable filters for deblending
H\alpha from [NII] lines by analyzing the flux errors obtained. We simulated
the OTELO data by convolving a complete set of synthetic HII galaxies in EW
with different widths of the OSIRIS TFs. We estimated relative flux errors of
the recovered H\alpha and [NII]6583 lines. We found that, for the red TF, a
FWHM of 12 A and a sampling of 5 A is an optimal combination that allow
deblending H\alpha from the [NII]6583 line with a flux error lower than 20%.
This combination will allow estimating SFRs and metallicities using the H\alpha
flux and the N2 method, respectively.Comment: 16 pages, 9 figures. Some authors added. Accepted for publication in
PAS
The role of impulsivity in dropout from treatment for cigarette smoking
AbstractImpulsivity is a variable that has been associated with drug use. This study analyzes impulsivity from two different paradigms, one considering it as a trait and the other based on its behavioral correlates, such as disinhibition and impulsive decision-making in the treatment prognosis (maintain abstinence, relapse and dropout) of smokers after outpatient treatment. The participants in the study were 113 smokers who requested treatment for nicotine addiction. They were assigned to three groups according to whether or not they remained abstinent one month after beginning treatment; thus, group 1 was abstinent, group 2 had relapsed, and group 3 had dropped out of treatment. The participants filled out the Semi-structured Interview for Smokers, the Fargerström Test for Nicotine Dependence, the Temperament and Character Inventory-Revised (TCI-R) and the Delay Discounting Task (DDT). The Delay Discounting variable presents lower scores in the dropout group than in the relapse and abstinent groups, with the highest scores in the relapse group. Differences were also found on the Harm Avoidance (HA) variable, with lower scores in the dropout group compared to the relapse group. The importance of these results lies in the consideration of the smoker’s personality profile in order to prevent both dropout and relapse
Relationship between the anterior forebrain mesocircuit and the default mode network in the structural bases of disorders of consciousness
The specific neural bases of disorders of consciousness (DOC) are still not well understood. Some studies have suggested that functional and structural impairments in the default mode network may play a role in explaining these disorders. In contrast, others have proposed that dysfunctions in the anterior forebrain mesocircuit involving striatum, globus pallidus, and thalamus may be the main underlying mechanism. Here, we provide the first report of structural integrity of fiber tracts connecting the nodes of the mesocircuit and the default mode network in 8 patients with DOC. We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale - Revised (CRS-R) scores. In contrast, fiber tracts interconnecting subcortical nodes were not significantly impaired. Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas. Our results suggest a strong relationship between the default mode network - and most importantly the precuneus - and the anterior forebrain mesocircuit in the neural basis of the DOC
New insights into FoxE1 functions: identification of direct FoxE1 targets in thyroid cells
This is an open-access article distributed under the terms of the Creative Commons Attribution License.[Background]: FoxE1 is a thyroid-specific forkhead transcription factor essential for thyroid gland development, as well as for the maintenance of the thyroid differentiated state in adults. FoxE1 recognizes and binds to a short DNA sequence present in thyroglobulin (Tg) and thyroperoxidase (Tpo) promoters, but FoxE1 binding to regulatory regions other than Tg and Tpo promoters remains almost unexplored. Improving knowledge of the regulatory functions of FoxE1 is necessary to clarify its role in endocrine syndromes and cancer susceptibility. [Methodology/Principal Finding]:I n order to further investigate downstream FoxE1 targets, we performed a genome-wide expression screening after knocking-down FoxE1 and obtained new insights into FoxE1 transcriptional networks in thyroid follicular cells. After validation, we confirmed Adamts9, Cdh1, Duox2 and S100a4 as upregulated genes and Casp4, Creld2, Dusp5, Etv5, Hsp5a, Nr4a2 and Tm4sf1 as downregulated genes when FoxE1 was silenced. In promoter regions of putative FoxE1-regulated genes and also in the promoters of the classical thyroid genes Nis, Pax8 and Titf1, we performed an in silico search of the FoxE1 binding motif that was in close proximity to the NF1/CTF binding sequence, as previously described for other forkhead factors. Using chromatin immunoprecipitation we detected specific in vivo FoxE1 binding to novel regulatory regions in two relevant thyroid genes, Nis and Duox2. Moreover, we demonstrated simultaneous binding of FoxE1 and NF1/CTF to the Nis upstream enhancer region, as well as a clear functional activation of the Nis promoter by both transcription factors. [Conclusions/Significance]:In search for potential downstream mediators of FoxE1 function in thyroid cells, we identified two novel direct FoxE1 target genes. To our knowledge, this is the first evidence regarding the implication of Nis and Duox2 in executing the transcriptional program triggered by FoxE1. Furthermore, this study points out the important role of FoxE1 in the regulation of a large number of genes in thyroid cells. © 2013 Fernández et al.This work was supported by Grants BFU-2010-16025 from the Dirección General de Proyectos de Investigación; RD06/0020/0060 and RD12/0036/0030 from FIS, Instituto de Salud Carlos III; and S2011/BMD-2328 TIRONET project from the Comunidad de Madrid (Spain). LP Fernández holds a postdoctoral grant of the Juan de la Cierva programme of the Spanish Government.Peer Reviewe
- …