How Water's Properties Are Encoded in Its Molecular Structure and Energies.

How are water's material properties encoded within the structure of the water molecule? This is pertinent to understanding Earth's living systems, its materials, its geochemistry and geophysics, and a broad spectrum of its industrial chemistry. Water has distinctive liquid and solid properties: It is highly cohesive. It has volumetric anomalies-water's solid (ice) floats on its liquid; pressure can melt the solid rather than freezing the liquid; heating can shrink the liquid. It has more solid phases than other materials. Its supercooled liquid has divergent thermodynamic response functions. Its glassy state is neither fragile nor strong. Its component ions-hydroxide and protons-diffuse much faster than other ions. Aqueous solvation of ions or oils entails large entropies and heat capacities. We review how these properties are encoded within water's molecular structure and energies, as understood from theories, simulations, and experiments. Like simpler liquids, water molecules are nearly spherical and interact with each other through van der Waals forces. Unlike simpler liquids, water's orientation-dependent hydrogen bonding leads to open tetrahedral cage-like structuring that contributes to its remarkable volumetric and thermal properties

Unexpected differences between thermal and photoinitiated cationic curing of a diglycidyl ether of bisphenol A modified with a multiarm star poly(styrene)-b-poly(ε-caprolactone) polymer

The effect of adding a multiarm star poly(styrene)-b-poly(ε-caprolactone) polymer on the cationic thermal and photoinitiated curing of diglycidyl ether of bisphenol A was studied. This star-polymer decelerated the thermal curing of diglycidyl ether of bisphenol A and modified the final structure of the epoxy matrix. The photocuring was influenced significantly by the addition of the multiarm star. When the proportion of this modifier added was 5%, much more time was necessary for complete photocuring (160 min at 40ºC). In the presence of 10% of modifier, the degree of photocuring reached was very low (0.196 at 120°C). A subsequent thermal post-curing was necessary to cure completely the system. During photocuring in presence of poly(styrene)-b-poly(ε-caprolactone), the formation of dormant species, which are reactivated when the temperature increases, takes places. The kinetics of the thermal curing and the photocuring was analyzed using an isoconversional method due to the complexity of the reactive process. Applying this method, it has been confirmed the dependence of activation energy on the degree of conversion. The fracture morphology analyzed by scanning electron microscopy exhibited a second phase originated during photocuring by the presence of the modifier

Nonsingular potentials from excited state factorization of a quantum system with position dependent mass

The modified factorization technique of a quantum system characterized by position-dependent mass Hamiltonian is presented. It has been shown that the singular superpotential defined in terms of a mass function and a excited state wave function of a given position-dependent mass Hamiltonian can be used to construct non-singular isospectral Hamiltonians. The method has been illustrated with the help of a few examples.Comment: Improved version accepted in J. Phys.

Dual-curable stereolithography resins for superior thermomechanical properties

Stereolithography (SL) stands out as a relatively fast additive manufacturing method to produce thermoset components with high resolutions. The majority of SL resins consist of acrylate monomers which result in materials with cur-ing-induced shrinkage problems and this, in addition to the incomplete and non-uniform conversions reached in the SL process, results in poor mechanical properties. To address this issue, a dual-curing formulation was developed by mixing an epoxy monomer into a commercial multi-acrylate SL resin: the first curing stage is acrylate free-radical photopolymerization at ambient temperature, and the second curing stage is cationic epoxy homopolymerization at higher temperatures. The fully dual-cured materials are macroscopically homogeneous, with nanoscale domains observed by Atomic Force Mi-croscopy (AFM), and with unimodal tan delta peaks observed in Dynamic Mechanical Analysis (DMA). The uncured material was storage stable at ambient conditions for at least 9 weeks since the epoxy part was virtually unreactive at these temper-atures. With the dual-cured materials, a nearly 10-fold increase in Young’s modulus was achieved over the neat acrylate resin. At the thermal curing stage, the presence of diperoxyketal thermal radical initiator to the liquid formulation facilitated the polymerization of unreacted acrylates that remained from the SL process simultaneously with epoxy homopolymerization and helped the material attain improved properties

A de novo complete BRCA1 gene deletion identified in a Spanish woman with early bilateral breast cancer

<p>Abstract</p> <p>Background</p> <p>Germline mutations in either of the two tumor-suppressor genes, <it>BRCA1 </it>and <it>BRCA2</it>, account for a significant proportion of hereditary breast and ovarian cancer cases. Most of these mutations consist of deletions, insertions, nonsense mutations, and splice variants, however an increasing number of large genomic rearrangements have been identified in these genes.</p> <p>Methods</p> <p>We analysed <it>BRCA1 </it>and <it>BRCA2 </it>genes by direct sequencing and MLPA. We confirmed the results by an alternative MLPA kit and characterized the <it>BRCA1 </it>deletion by Array CGH.</p> <p>Results</p> <p>We describe the first case of a patient with no strong family history of the disease who developed early-onset bilateral breast cancer with a <it>de novo </it>complete <it>BRCA1 </it>gene deletion in the germinal line. The detected deletion started from the region surrounding the <it>VAT1 </it><it>locus </it>to the beginning of <it>NBR1 </it>gene, including the <it>RND2</it>, Ψ<it>BRCA1</it>, <it>BRCA1 </it>and <it>NBR2 </it>complete genes.</p> <p>Conclusion</p> <p>This finding supports the large genomic rearrangement screening of <it>BRCA </it>genes in young breast cancer patients without family history, as well as in hereditary breast and ovarian cancer families previously tested negative for other variations.</p

Tecnologías del hidrógeno

El interés por las tecnologías del hidrógeno ha crecido en los últimos años, principalmente porque una economía basada en el hidrógeno puede dar respuesta a los grandes desafíos de la economía global del futuro: seguridad energética y cambio climático. Aprovechando este impulso, cada vez son más los países que están implementando un número creciente de políticas en favor del hidrógeno. Prueba de ello es la Estrategia Europea del Hidrógeno que establece al hidrógeno como un elemento esencial en| la descarbonización total del actual sistema energético para alcanzar el compromiso de la UE con la neutralidad de carbono en 2050. No obstante, el desarrollo exitoso de las tecnologías del hidrógeno requiere que todos los actores, incluidos los sectores público y privado, aumenten sus esfuerzos para acelerar su despliegue y hacer que su implantación a gran escala resulte competitiva. Los grupos de investigación que forman parte del área de trabajo de tecnologías del hidrógeno, dentro de la Plataforma Temática Interdisciplinar PTI Mobility 2030 del CSIC, trabajan en este sentido, desarrollando su labor en áreas tan diversas como la generación, el almacenamiento, la distribución y los usos del hidrógeno. The interest in hydrogen technologies has grown in recent years, mainly because an economy based on hydrogen can help to solve important challenges related to the global economy of the future: energy security and climate change. Taking advantage of this momentum, more and more countries are implementing a growing number of policies related to hydrogen. Indeed, the European Hydrogen Strategy establishes hydrogen as essential drivers for the total decarbonization of the current energy system in order to achieve the Ells commitment related to carbon neutrality by 2050. However, the successful development of the hydrogen technologies requires the collaboration of the public and private sectors to accelerate its deployment and make more competitive its implementation at large-scale. The research groups that take part of the line of work dedicated to hydrogen technologies, within the CSIC Interdisciplinary Thematic Platform PTI Mobility 2030, work in this regard, developing their investigations in several important areas related to the hydrogen technologies such as hydrogen generation, storage, distribution and uses

Global and regional IUCN red list assessments: 4

In this contribution, the conservation status assessments of three vascular plants are presented following to IUCN categories and criteria. It includes the assessment at global level of Saxifraga caprariae Mannocci, Ferretti, Mazzoncini &amp; Viciani and S. montis-christi Mannocci, Ferretti, Mazzoncini &amp; Viciani and the regional assessment of Halocnemum cruciatum (Forssk.) Tod. (Spain)

Coherent state of a nonlinear oscillator and its revival dynamics

The coherent state of a nonlinear oscillator having a nonlinear spectrum is constructed using Gazeau Klauder formalism. The weighting distribution and the Mandel parameter are studied. Details of the revival structure arising from different time scales underlying the quadratic energy spectrum are investigated by the phase analysis of the autocorrelation function

LBECA: A Low Background Electron Counting Apparatus for Sub-GeV Dark Matter Detection

Two-phase noble liquid detectors, with large target masses and effective background reduction, are currently leading the dark matter direct detection for WIMP masses above a few GeV. Due to their sensitivity to single ionized electron signals, these detectors were shown to also have strong constraints for sub-GeV dark matter via their scattering on electrons. In fact, the most stringent direct detection constraints for sub-GeV dark matter down to as low as ~5 MeV come from noble liquid detectors, namely XENON10, DarkSide-50, XENON100 and XENON1T, although these experiments still suffer from high background at single or a few electron level. LBECA is a planned 100-kg scale liquid xenon detector with significant reduction of the single and a few electron background. The experiment will improve the sensitivity to sub-GeV dark matter by three orders of magnitude compared to the current best constraints.Comment: to appear in the Proceedings of the TAUP 2019 Conferenc