Habits, norms and use of technologies at home from a gender perspective in early childhood

The use of technologies at home directly influences how children perceive them for their learning at school. Numerous studies have focused on the different ways in which digital technologies are used at home and in schools. These studies attempt to explain how previous experience and knowledge can be linked to the use of technologies at school, the differences between home and school literacies, or how socio-economic status influences the availability of technology in these socio-educational institutions. All of them show that technology has become part of children's lives. Consequently, the aim of this study was to obtain information about the habits, norms and use of technology by children aged 2-6 years in their homes and the differences between genders. To this end, a validated questionnaire was created. A total of 1016 parents completed the questionnaire. The results show the most used technologies, the time of use and whom they are used with, as well as the rules imposed and their opinion about this use. Likewise, there are significant differences that lead to carry out and discuss proposals for STEAM work in Early Childhood Education classrooms in order to empower students

Assessing the influence of distinct culture media on human pre-implantation development using single-embryo transcriptomics

The use of assisted reproductive technologies is consistently rising across the world. However, making an informed choice on which embryo culture medium should be preferred to ensure satisfactory pregnancy rates and the health of future children critically lacks scientific background. In particular, embryos within their first days of development are highly sensitive to their micro-environment, and it is unknown how their transcriptome adapts to different embryo culture compositions. Here, we determined the impact of culture media composition on gene expression in human pre-implantation embryos. By employing single-embryo RNA-sequencing after 2 or 5 days of the post-fertilization culture in different commercially available media (Ferticult, Global, and SSM), we revealed medium-specific differences in gene expression changes. Embryos cultured pre-compaction until day 2 in Ferticult or Global media notably displayed 266 differentially expressed genes, which were related to essential developmental pathways. Herein, 19 of them could have a key role in early development, based on their previously described dynamic expression changes across development. When embryos were cultured after day 2 in the same media considered more suitable because of its amino acid enrichment, 18 differentially expressed genes thought to be involved in the transition from early to later embryonic stages were identified. Overall, the differences were reduced at the blastocyst stage, highlighting the ability of embryos conceived in a suboptimal in vitro culture medium to mitigate the transcriptomic profile acquired under different pre-compaction environments

New Intermediate band sulphide nanoparticles acting in the full visible light range spectra as an active photocatalyst

Nowadays one of the challenges of materials science is to find new technologies that will be able to make the most of renewable energies. An example of new proposals in this field are the intermediate-band (IB) materials, which promise higher efficiencies in photovoltaic applications (through the intermediate band solar cells), or in heterogeneous photocatalysis (using nanoparticles of them, for the light-induced degradation of pollutants or for the efficient photoevolution of hydrogen from water). An IB material consists in a semiconductor in which gap a new level is introduced [1], the intermediate band (IB), which should be partially filled by electrons and completely separated of the valence band (VB) and of the conduction band (CB). This scheme (figure 1) allows an electron from the VB to be promoted to the IB, and from the latter to the CB, upon absorption of photons with energy below the band gap Eg, so that energy can be absorbed in a wider range of the solar spectrum and a higher current can be obtained without sacrificing the photovoltage (or the chemical driving force) corresponding to the full bandgap Eg, thus increasing the overall efficiency. This concept, applied to photocatalysis, would allow using photons of a wider visible range while keeping the same redox capacity. It is important to note that this concept differs from the classic photocatalyst doping principle, which essentially tries just to decrease the bandgap. This new type of materials would keep the full bandgap potential but would use also lower energy photons. In our group several IB materials have been proposed, mainly for the photovoltaic application, based on extensively doping known semiconductors with transition metals [2], examining with DFT calculations their electronic structures. Here we refer to In2S3 and SnS2, which contain octahedral cations; when doped with Ti or V an IB is formed according to quantum calculations (see e.g. figure 2). We have used a solvotermal synthesis method to prepare in nanocrystalline form the In2S3 thiospinel and the layered compound SnS2 (which when undoped have bandgaps of 2.0 and 2.2 eV respectively) where the cation is substituted by vanadium at a ?10% level. This substitution has been studied, characterizing the materials by different physical and chemical techniques (TXRF, XRD, HR-TEM/EDS) (see e.g. figure 3) and verifying with UV spectrometry that this substitution introduces in the spectrum the sub-bandgap features predicted by the calculations (figure 4). For both sulphide type nanoparticles (doped and undoped) the photocatalytic activity was studied by following at room temperature the oxidation of formic acid in aqueous suspension, a simple reaction which is easily monitored by UV-Vis spectroscopy. The spectral response of the process is measured using a collection of band pass filters that allow only some wavelengths into the reaction system. Thanks to this method the spectral range in which the materials are active in the photodecomposition (which coincides with the band gap for the undoped samples) can be checked, proving that for the vanadium substituted samples this range is increased, making possible to cover all the visible light range. Furthermore it is checked that these new materials are more photocorrosion resistant than the toxic CdS witch is a well know compound frequently used in tests of visible light photocatalysis. These materials are thus promising not only for degradation of pollutants (or for photovoltaic cells) but also for efficient photoevolution of hydrogen from water; work in this direction is now being pursued

Sulfuros fotocatalizadores que utilizan ampliamente el espectro de luz visible

Cuando se usa fotocatálisis, tanto para procesos de descontaminación como para síntesis química específica y (especialmente) para aprovechamiento de energía solar, importa aprovechar un rango muy amplio de luz visible. Para ello se estudian hoy principalmente óxidos (con o sin adición de aniones que disminuyen el gap como el nitrógeno); los sulfuros, como el bien conocido CdS, tienen estabilidad limitada, sobre todo para procesos de fotooxidación en presencia de agua en los que sufren corrosión. Aquí se presentan estudios sobre sulfuros como el In2S3 y el SnS2 (con bandgaps respectivos de 2.0 y 2.2 eV [1]) cuyos metales tienen mayor valencia y coordinación octaédrica, y en los que por ambos factores cabe suponer que su red cristalina, más compacta, tendrá mayor estabilidad. Se muestra también que mediante un dopado importante con vanadio se puede extender su rango espectral de fotoactividad, lo que se atribuye a la formación de una banda intermedia que posibilita el uso de dos fotones con energía inferior al bandgap para conseguir una excitación completa en el semiconductor; este proceso ha sido propuesto últimamente para aumentar el rendimiento de las células fotovoltaicas

Vanadium-Doped In and Sn Sulphides: Photocatalysts able to use the whole visible light spectrum

Using photocatalysis for energy applications depends, more than for environmental purposes or selective chemical synthesis, on converting as much of the solar spectrum as possible; the best photocatalyst, titania, is far from this. Many efforts are pursued to use better that spectrum in photocatalysis, by doping titania or using other materials (mainly oxides, nitrides and sulphides) to obtain a lower bandgap, even if this means decreasing the chemical potential of the electron-hole pairs. Here we introduce an alternative scheme, using an idea recently proposed for photovoltaics: the intermediate band (IB) materials. It consists in introducing in the gap of a semiconductor an intermediate level which, acting like a stepstone, allows an electron jumping from the valence band to the conduction band in two steps, each one absorbing one sub-bandgap photon. For this the IB must be partially filled, to allow both sub-bandgap transitions to proceed at comparable rates; must be made of delocalized states to minimize nonradiative recombination; and should not communicate electronically with the outer world. For photovoltaic use the optimum efficiency so achievable, over 1.5 times that given by a normal semiconductor, is obtained with an overall bandgap around 2.0 eV (which would be near-optimal also for water phtosplitting). Note that this scheme differs from the doping principle usually considered in photocatalysis, which just tries to decrease the bandgap; its aim is to keep the full bandgap chemical potential but using also lower energy photons. In the past we have proposed several IB materials based on extensively doping known semiconductors with light transition metals, checking first of all with quantum calculations that the desired IB structure results. Subsequently we have synthesized in powder form two of them: the thiospinel In2S3 and the layered compound SnS2 (having bandgaps of 2.0 and 2.2 eV respectively) where the octahedral cation is substituted at a â?10% level with vanadium, and we have verified that this substitution introduces in the absorption spectrum the sub-bandgap features predicted by the calculations. With these materials we have verified, using a simple reaction (formic acid oxidation), that the photocatalytic spectral response is indeed extended to longer wavelengths, being able to use even 700 nm photons, without largely degrading the response for above-bandgap photons (i.e. strong recombination is not induced) [3b, 4]. These materials are thus promising for efficient photoevolution of hydrogen from water; work on this is being pursued, the results of which will be presented

New materials for intermediate band photovoltaic cells. A theoretical and experimental approach

Density functional theory calculations of certain transition-metal doped semiconductors show a partially occupied relatively narrow band located between valence band and conduction band. These novel systems, containing the metallic band, are called intermediate-band materials. They have enhanced optoelectronic properties which allow an increase in solar energy conversion efficiency of conventional solar cells. We previously proposed III-V, chalcopyrite and sulfide derived compounds showing desirable characteristics to produce the intermediate band of interest inside the band-gap. In order to obtain further intermediate-band material proposals, this work focuses on studing other compounds constituted mainly by tetravalent elements. The first proposal is vanadium substituting Sn atoms in SnS2 , the second one is composed by type II silicon clathrate with two possibilities: vanadium substituting Si and Ag occluded in the intra-crystalline cavities. UV-Vis-NIR spectra of some of these systems experimentally synthesized show an agreement with previous theoretical prediction

Intermediate band materials for more efficient solar energy use: quantum modelling and experimental realizations

The intermediate band (IB) solar cell (Fig. 1) has been proposed [1] to increase photovoltaic efficiency by a factor above 1.5, based on the absorption of two sub-bandgap photons to promote an electron across the bandgap. To realize this principle, that can be applied also to obtain efficient photocatalysis with sunlight, we proposed in recent years several materials where a metal or heavy element, substituting for an electropositive atom in a known semiconductor that has an appropriate band gap width (around 2 eV), forms inside the gap the partially filled levels needed for this ai

Endogenous retroviral insertions drive non-canonical imprinting in extra-embryonic tissues.

BACKGROUND: Genomic imprinting is an epigenetic phenomenon that allows a subset of genes to be expressed mono-allelically based on the parent of origin and is typically regulated by differential DNA methylation inherited from gametes. Imprinting is pervasive in murine extra-embryonic lineages, and uniquely, the imprinting of several genes has been found to be conferred non-canonically through maternally inherited repressive histone modification H3K27me3. However, the underlying regulatory mechanisms of non-canonical imprinting in post-implantation development remain unexplored. RESULTS: We identify imprinted regions in post-implantation epiblast and extra-embryonic ectoderm (ExE) by assaying allelic histone modifications (H3K4me3, H3K36me3, H3K27me3), gene expression, and DNA methylation in reciprocal C57BL/6 and CAST hybrid embryos. We distinguish loci with DNA methylation-dependent (canonical) and independent (non-canonical) imprinting by assaying hybrid embryos with ablated maternally inherited DNA methylation. We find that non-canonical imprints are localized to endogenous retrovirus-K (ERVK) long terminal repeats (LTRs), which act as imprinted promoters specifically in extra-embryonic lineages. Transcribed ERVK LTRs are CpG-rich and located in close proximity to gene promoters, and imprinting status is determined by their epigenetic patterning in the oocyte. Finally, we show that oocyte-derived H3K27me3 associated with non-canonical imprints is not maintained beyond pre-implantation development at these elements and is replaced by secondary imprinted DNA methylation on the maternal allele in post-implantation ExE, while being completely silenced by bi-allelic DNA methylation in the epiblast. CONCLUSIONS: This study reveals distinct epigenetic mechanisms regulating non-canonical imprinted gene expression between embryonic and extra-embryonic development and identifies an integral role for ERVK LTR repetitive elements

Pioglitazone modulates the vascular contractility in hypertension by interference with ET-1 pathway

Endothelin-1 (ET-1) is an important modulator of the vascular tone and a proinflammatory molecule that contributes to the vascular damage observed in hypertension. Peroxisome-proliferator activated receptors-γ (PPARγ) agonists show cardioprotective properties by decreasing inflammatory molecules such as COX-2 and reactive oxygen species (ROS), among others. We investigated the possible modulatory effect of PPARγ activation on the vascular effects of ET-1 in hypertension. In spontaneously hypertensive rats (SHR), but not in normotensive rats, ET-1 enhanced phenylephrineinduced contraction through ETA by a mechanism dependent on activation of TP receptors by COX-2- derived prostacyclin and reduction in NO bioavailability due to enhanced ROS production. In SHR, the PPARγ agonist pioglitazone (2.5 mg/Kg·day, 28 days) reduced the increased ETA levels and increased those of ETB. After pioglitazone treatment of SHR, ET-1 through ETB decreased ROS levels that resulted in increased NO bioavailability and diminished phenylephrine contraction. In vascular smooth muscle cells from SHR, ET-1 increased ROS production through AP-1 and NFκB activation, leading to enhanced COX-2 expression. These effects were blocked by pioglitazone. In summary, in hypertension, pioglitazone shifts the vascular ETA/ETB ratio, reduces ROS/COX-2 activation and increases NO availability; these changes explain the effect of ET-1 decreasing phenylephrine-induced contractionThis work was supported by the Spanish Ministerio de Ciencia, Innovación y Universidades (SAF2015-69294-R and SAF2016-80305-P), Instituto de Salud Carlos III (CIBER de Enfermedades Cardiovasculares, CB16.11.00286), Comunidad de Madrid (B2017/BMD-3676) and Fondo Europeo de Desarrollo Regional (FEDER) a way to build Europ