Anisotropy in nanocellular polymers promoted by the addition of needle‐like sepiolites

This work presents a new strategy for obtaining nanocellular materials with high anisotropy ratios by means of the addition of needle‐like nanoparticles. Nanocellular polymers are of great interest due to their outstanding properties, whereas anisotropic structures allow the realization of improved thermal and mechanical properties in certain directions. Nanocomposites based on poly(methyl methacrylate) (PMMA) with nanometric sepiolites are generated by extrusion. From the extruded filaments, cellular materials are produced using a two‐step gas dissolution foaming method. The effect of adding various types and contents of sepiolites is investigated. As a result of the extrusion process, the needle‐like sepiolites are aligned in the machine direction in the solid nanocomposites. Regarding the cellular materials, the addition of sepiolites allows one to obtain anisotropic nanocellular polymers with cell sizes of 150 to 420 nm and cell nucleation densities of 1013–1014 nuclei cm−3 and presenting anisotropy ratios ranging from 1.38 to 2.15, the extrusion direction being the direction of the anisotropy. To explain the appearance of anisotropy, a mechanism based on cell coalescence is proposed and discussed. In addition, it is shown that it is possible to control the anisotropy ratio of the PMMA/sepiolite nanocellular polymers by changing the amount of well‐dispersed sepiolites in the solid nanocomposites

Kinetic study of the gas-phase reaction of atomic chlorine with a series of aldehydes

The reactions of Cl atoms with a series of unsaturated aldehydes have been investigated for the first time using a relative method. In order to obtain additional information for a qualitative structure versus reactivity discussion, we have also determined the rate coefficients for the reactions of atomic chlorine with their respective saturated aldehydes. These relative measurements were performed at room temperature and atmospheric pressure of air and N₂, by using ethane, propene and 1-butene as reference compounds. The weighted average relative rate constants obtained, k_Cl&plusmn;2&sigma; (in units of cm³ molecule^&minus;1 s^&minus;1) were: trans-2-pentenal (1.31&plusmn;0.19)&times;10^&minus;10; trans-2-hexenal (1.92&plusmn;0.22)&times;10^&minus;10; trans-2-heptenal (2.40&plusmn;0.29)&times;10^&minus;10; n-pentanal (2.56&plusmn;0.27)&times;10^&minus;10; n-hexanal (2.88&plusmn;0.37)&times;10^&minus;10; n-heptanal (3.00&plusmn;0.34)&times;10^&minus;10. <P style='line-height: 20px;'> Finally, results and atmospheric implications are discussed and compared with the reactivity with OH and NO₃ radicals

Quasiparticle energies for large molecules: a tight-binding GW approach

We present a tight-binding based GW approach for the calculation of quasiparticle energy levels in confined systems such as molecules. Key quantities in the GW formalism like the microscopic dielectric function or the screened Coulomb interaction are expressed in a minimal basis of spherically averaged atomic orbitals. All necessary integrals are either precalculated or approximated without resorting to empirical data. The method is validated against first principles results for benzene and anthracene, where good agreement is found for levels close to the frontier orbitals. Further, the size dependence of the quasiparticle gap is studied for conformers of the polyacenes ($C_{4n+2}H_{2n+4}$) up to n = 30.Comment: 10 pages, 5 eps figures submitted to Phys. Rev.

Physical activity and bone health in schoolchildren: the mediating role of fitness and body fat

This is the final version of the article. Available from Public Library of Science via the DOI in this record.BACKGROUND: The relationship between physical activity (PA) and bone health is well known, although the role of percent body fat (%BF) and fitness as confounders or mediators in this relationship remains uncertain. OBJECTIVE: To examine whether the association between PA and bone mineral content (BMC) is mediated by %BF and cardiorespiratory fitness (CRF). METHODS: In this cross sectional study, BMC, total %BF (by DXA), vigorous PA (VPA), CRF, age and height were measured in 132 schoolchildren (62 boys, aged 8-11 years). ANCOVA was used to test differences in BMC by %BF, CRF and VPA, controlling for different sets of confounders. Simple mediation analyses and serial multiple mediation analyses were fitted to examine whether the relationship between PA and BMC is mediated by %BF and fitness. RESULTS: Children with high %BF had higher total body BMC than their peers after controlling for all sets of confounders. Children with good CRF or VPA had significantly less total body BMC after controlling for age and sex but in children with good CRF this inverse relation disappeared after adjusting by %BF. %BF and CRF both act as a full mediator in the association between VPA and BMC, after inclusion of the potential confounders in the models. CONCLUSION: Fitness and %BF seem to have a mediator role on the relationship between physical activity and bone mass.This study was funded by grant numbers PII1I09-0259-9898 and POII10-0208-5325 from the Ministry of Education and Science - Junta de Comunidades de Castilla-La Mancha, and Ministry of Health (FIS grant number PI081297). Additional funding was provided by the Research Network on Preventative Activities and Health Promotion (RD06/0018/0038)

Isobutyl acetate: electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations

The high-resolution vacuum ultraviolet photoabsorption spectrum of isobutyl acetate, C6H12O2, is presented here and was measured over the energy range 4.3–10.8 eV (290–115 nm). Valence and Rydberg transitions with their associated vibronic series have been observed in the photoabsorption spectrum and are assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. The measured photoabsorption cross sections have been used to calculate the photolysis lifetime of this ester in the Earth’s upper atmosphere (20–50 km). Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of isobutyl acetate and are compared with a photoelectron spectrum (from 9.5 to 16.7 eV), recorded for the first time. Vibrational structure is observed in the first photoelectron band of this molecule

Contribución al estudio de la entomofauna del Monte del Estado Selladores-Contadero (Jaén)

By sundry capture methods it is achieved an insect collecting in 6 plots that are located in Monte de Selladores-Contadero, Jaén (Spain). The taxonomic analysis about 4.787 specimen gives as a result the identification of 275 species belonging at 12 Orders and 82 Families.Mediante diversos m&eacute;todos de captura se realiza una recolecci&oacute;n de insectos en 6 parcelas ubicadas en el Monte de Selladores-Contadero (Ja&eacute;n). El an&aacute;lisis taxon&oacute;mico sobre 4.787 espec&iacute;menes, ofrece como resultado la identificaci&oacute;n de 275 especies correspondientes a 12 &Oacute;rdenes y 82 Familias

Association between Mediterranean diet and metal(loid) exposure in 4-5-year-old children living in Spain

This study was funded by CIDEGENT/2020/050 and grants from Spanish Institute of Health Carlos III, ISCIII-FEDER: PI07/0314, PI11/01007, PI16/1288, PI19/1338, PI04/2018, PI09/02311, PI13/02429, PI18/00909, PIS06/0867, PI09/00090, PI13/02187, PI04/1436; PI08/1151, PI18/01142, PI03/1615, PI04/1509, PI04/1112, PI04/1931, PI05/1079, PI05/1052, PI06/1213, PI07/0314, PI09/02647, PI11/02591, PI11/02038, PI13/1944, PI13/2032, PI14/00891, PI14/01687 and PI17/00663. FIS-FSEE: 7/00260, Red INMA G03/176; CB06/02/0041 incl. FEDER funds. Grants from UE (FP7-ENV-2011 cod 282957 and HEALTH.2010.2.4.5–1). We acknowledge support from the Spanish Ministry of Science and Innovation and the State Research Agency through the “Centro de Excelencia Severo Ochoa 2019–2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program. Obra Social Cajastur/Fundación Liberbank and Universidad de Oviedo Miguel Servet fellowship (CP16/00128, CP11/00178, CP15/00025, and CPII16/00051) funded by Instituto de Salud Carlos III and cofounded by European Social Fund “Investing in your future”. Institute of Health Carlos III(Grant CD21/00186- Sara Borell Postdoctoral Fellowship) and co-funded by the European Union. Spanish Ministry of Universities (Margarita Salas Grant MS21-133) and co-funded by European UnionNext Generation EU. H2020 No 874583, the ATHLETE project.Notario-Barandiaran L, Irizar A, Begoña-Zubero M, Soler-Blasco R, Riutort-Mayol G, Fernández-Somoano A, Tardón A, Casas M, Vrijheid M, Meharg A, Carey M, Meharg C, Ralphs K, McCreanor C, Grimalt JO, Vioque J, Signes-Pastor A

Accurate detection and quantification of SARS-CoV-2 genomic and subgenomic mRNAs by ddPCR and meta-transcriptomics analysis

SARS-CoV-2 replication requires the synthesis of a set of structural proteins expressed through discontinuous transcription of ten subgenomic mRNAs (sgmRNAs). Here, we have fine-tuned droplet digital PCR (ddPCR) assays to accurately detect and quantify SARS-CoV-2 genomic ORF1ab and sgmRNAs for the nucleocapsid (N) and spike (S) proteins. We analyzed 166 RNA samples from anonymized SARS-CoV-2 positive subjects and we observed a recurrent and characteristic pattern of sgmRNAs expression in relation to the total viral RNA content. Additionally, expression profiles of sgmRNAs, as determined by meta-transcriptomics sequencing of a subset of 110 RNA samples, were highly correlated with those obtained by ddPCR. By providing a comprehensive and dynamic snapshot of the levels of SARS-CoV-2 sgmRNAs in infected individuals, our results may contribute a better understanding of the dynamics of transcription and expression of the genome of SARS-CoV-2 and facilitate the development of more accurate molecular diagnostic tools for the stratification of COVID-19 patients