Estudio de la energía superficial de matrices orgánicas por cromatografía de gases inversa para su aplicación en el desarrollo de materiales compuestos

Para que los materiales compuestos sean los adecuados en todas las aplicaciones debe prestarse especial atención a la interfase entre la matriz y la fibra. Ésta es sin duda la zona más importante y vulnerable de dichos materiales. Una técnica ideal para el estudio de dicha interfase es la Cromatografía de Gases Inversa (IGC). La IGC es una de las pocas técnicas de estudio de superficies que aporta datos de la "actividad superficial" de un sólido aunque con ella no se "identifiquen" átomos concretos o grupos funcionales. Determina la afinidad de la superficie de estudio con los diferentes grupos funcionales del entorno. Son muchas las ventajas que presenta la IGC, quizás la más ventajosa es la rapidez en la obtención de los datos. Además, el método es extraordinariamente versátil a la hora de observar el efecto de la temperatura en las propiedades de la superficie. Y lo más importante, el montaje experimental es muy sencillo y económico. Se pretende demostrar las posibilidades que ofrece la técnica de IGC en el estudio de las propiedades superficiales de cinco distintas matrices orgánicas habituales en el desarrollo de materiales compuestos avanzados (resinas fenólicas, furánicas, cianoéster y epoxi) y de un material polimérico de referencia apolar (polietileno). Se propone un nuevo método de cálculo de la actividad superficial de los materiales de estudio, en base a la introducción de las interacciones de Debye, ignoradas hasta ahora en los trabajos de IGC que aparecen en la bibliografía. Se realiza una estimación del área de todos los patrones con la ayuda de los radios atómicos y la longitud de los enlaces de las moléculas diatómicas descritos en la bibliografía. Al mismo tiempo, se propone el uso de la serie de los n-alcoholes como patrones polares, porque las ventajas aportadas en cuánto a la fiabilidad de las medidas y al cálculo de la interacción del dipolo OH serán determinantes en el estudio de la posible formación de los enlaces de hidrógeno en los materiales analizados. Por último, se realizó un "mapeo" de superficie de las distintas matrices orgánicas de naturaleza polimérica con la posibilidad de realizar la elección de la matriz más adecuada para el desarrollo de un material compuesto

Enantioselective Crystallization of Sodium Chlorate in the Presence of Racemic Hydrophobic Amino Acids and Static Magnetic Fields

We study the bias induced by a weak (200 mT) external magnetic field on the preferred handedness of sodium chlorate crystals obtained by slow evaporation at ambient conditions of its saturated saline solution with 20 ppm of added racemic (dl) hydrophobic amino acids. By applying the Fisher test to pairs of experiments with opposing magnetic field orientation we conclude, with a confidence level of 99.7%, that at the water-air interface of this saline solution there is an enantioselective magnetic interaction that acts upon racemic mixtures of hydrophobic chiral amino acids. This interaction has been observed with the three tested racemic hydrophobic amino acids: dl-Phe, dl-Try and dl-Trp, at ambient conditions and in spite of the ubiquitous chiral organic contamination. This enantioselective magnetic dependence is not observed when there is only one handedness of added chiral amino-acid, if the added amino acid is not chiral or if there is no additive. This effect has been confirmed with a double blind test. This novel experimental observation may have implications for our view of plausible initial prebiotic scenarios and of the roles of the geomagnetic field in homochirality in the biosphere.This research was supported by the Instituto Nacional de Técnica Aerospacial (INTA) and by the grant AYA2006-15648-C02-02 of the Ministerio de Educación y Ciencia (Spain) and by the project grants AYA2011-25720 and AYA2012-38707 of MINECO (Spain).We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

Occurrence and transport of microplastics sampled within and above the planetary boundary layer.

Nowadays, there is no direct evidence about the presence of microplastics (MPs) in the atmosphere above ground level. Here, we investigated the occurrence, chemical composition, shape, and size of MPs in aircraft sampling campaigns flying within and above the planetary boundary layer (PBL). The results showed that MPs were present with concentrations ranging from 1.5 MPs m−3 above rural areas to 13.9 MPs m−3 above urban areas. MPs represented up to almost one third of the total amount of microparticles collected. Fourier Transform Infrared Spectroscopy allowed identifying seven types of MPs with the highest diversity corresponding to urban areas. Atmospheric transport and deposition simulations were performed using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Air mass trajectory analyses showed that MPs could be transported more than 1000 km before being deposited. This pioneer study is the first evidence of the microplastic presence above PBL and their potential long-range transport from their point of release even crossing distant borders.We also acknowledge support from the EnviroPlaNet Network Thematic Newtork of Micro- and Nanoplastics in the Environment (RED2018-102345-T; Ministerio de Ciencia, Innovación y Universidades). We thank the financial support provided by the Spanish Ministerio de Ciencia, Innovación y Universidades (CTM2016-74927-C2-1-R/2-R, CGL2015-69758-P, CGL2017-92086-EXP, RTI2018-094867-B-I00) and National Institute for Aerospace Technology (PAI/APL/001/09)

Simple Organics and Biomonomers Identified in HCN Polymers: An Overview

Hydrogen cyanide (HCN) is a ubiquitous molecule in the Universe. It is a compound that is easily produced in significant yields in prebiotic simulation experiments using a reducing atmosphere. HCN can spontaneously polymerise under a wide set of experimental conditions. It has even been proposed that HCN polymers could be present in objects such as asteroids, moons, planets and, in particular, comets. Moreover, it has been suggested that these polymers could play an important role in the origin of life. In this review, the simple organics and biomonomers that have been detected in HCN polymers, the analytical techniques and procedures that have been used to detect and characterise these molecules and an exhaustive classification of the experimental/environmental conditions that favour the formation of HCN polymers are summarised. Nucleobases, amino acids, carboxylic acids, cofactor derivatives and other compounds have been identified in HCN polymers. The great molecular diversity found in HCN polymers encourages their placement at the central core of a plausible protobiological system.The authors used the research facilities of Centro de Astrobiología (CAB) and were supported by the Instituto Nacional de Técnica Aeroespacial “Esteban Terradas” (INTA) and the projects AYA2009-13920-C02-01 of the Ministerio de Ciencia e Innovación (Spain). Also we thank the support of the Economy and Competitivity Ministry (Project AYA2011-25720).We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

The effect of stirring on sodium chlorate crystallization under symmetry breaking conditions

6 pages, 3 figures, 1 table.-- PACS classification codes: 81.10.Dn; 64.60.Qb; 67.57.Pq; 02.70.Rr.The effect of the stirring rate on the crystallization of sodium chlorate was studied in more than 200 experiments using a set-up that allows to perform sets of 20 simultaneous experiments. The crystallization conditions were those that according to previous results lead to only one of both L and D enantiomorphic forms under stirring. The probability of D crystallization was determined using a statistical analysis based on the central limit theorem. The stirring dependence of induction times and crystal size distribution is reported. The stirring effect was correlated with differences between surface and bulk crystallization. The probability of D crystallization was detected to be slightly higher than that of the L, in contradiction with some previous reports, and that might be attributed to the chiral contamination of the bio-organic world on the starting materials and on the system. Our analysis allows to detect that the D-enantiomorph induction by chiral contamination occurs mainly in the nucleation at the interface air/water, which can be related to the expected higher concentration of the contaminants (bioorganic chiral amphiphiles e.g. DNA or proteins) on the surface of the solution.The authors are thankful to the Centro de Astrobiología (CAB) and to the Research Project No AYA2006-15648-CO2-02 from Spanish Ministry of Education and Science. One of us (MAH) gratefully acknowledges support from the Universidad Complutense through Acción Especial AES/06-14364.Peer reviewe

Simple Organics and Biomonomers Identified in HCN Polymers: An Overview

lif

Prebiotic microreactors: A synthesis of purines and dihydroxy compounds in aqueous aerosol

20 pages, 9 figures, 3 tables, 1 appendix.-- Published online: 29 Nov. 2006.We report the synthesis of purine bases and other heterocycles and the formation of amino acids, hydroxy acids and dihydroxy compounds by the spark activation of an atmosphere of methane, nitrogen and hydrogen, in the presence of an aqueous aerosol. With the aid of the interface air–water, the organic material obtained shows greater amounts and diversity of molecules with biological interest than the products obtained in the absence of an aerosol. Our results support the suggestion that aerosols may have played a significant role in the prebiotic origin of molecular diversity and evolution.The authors acknowledge the Centro de Astrobiología (CAB) for the research facilities and the grants from Instituto Nacional de Técnica Aeroespacial ‘Esteban Terradas’ (INTA).Peer reviewe

The effects of ferrous and other ions on the abiotic formation of biomolecules using aqueous aerosols and spark discharges

15 pages, 4 figures, 3 tables.-- PMID: 17899439 [PubMed].-- ISI Article Identifier: 000251368300004.-- Printed version published Dec 2007.It has been postulated that the oceans on early Earth had a salinity of 1.5 to 2 times the modern value and a pH between 4 and 10. Moreover, the presence of the banded iron formations shows that Fe(+2) was present in significant concentrations in the primitive oceans. Assuming the hypotheses above, in this work we explore the effects of Fe(+2) and other ions in the generation of biomolecules in prebiotic simulation experiments using spark discharges and aqueous aerosols. These aerosols have been prepared using different sources of Fe(+2), such as FeS, FeCl(2) and FeCO(3), and other salts (alkaline and alkaline earth chlorides and sodium bicarbonate at pH = 5.8). In all these experiments, we observed the formation of some amino acids, carboxylic acids and heterocycles, involved in biological processes. An interesting consequence of the presence of soluble Fe(+2) was the formation of Prussian Blue, Fe(4)[Fe(CN)(6)](3), which has been suggested as a possible reservoir of HCN in the initial prebiotic conditions on the Earth.The authors have used the research facilities of Centro de Astrobiología and have been supported by Instituto Nacional de Técnica Aeroespacial "Esteban Terradas" and the project AYA2006-15648-C02-02 of the Ministerio of Educación y Ciencia (Spain).Peer reviewe

Method for crystallisation from a solution

The present invention relates to a novel method and to a device for obtaining crystals from a substance, comprising: (i) preparing a saturated dissolution of the substance to be crystallized in a suitable solvent in a reaction vessel; (ii) generating an aerosol in the reaction vessel; (iii) crystallizing the substance; and (iv) recovering the crystals at the bottom of the reaction vessel. The method is especially suitable for crystallizing substances which are typically difficult to crystallize and can lead to a chiral amplification result.La presente invención relaciona a un nuevo método y a un dispositivo para obtener los cristales de una sustancia, comprendiendo: (i) preparando una disolución saturada de la sustancia que se cristalizará en un disolvente adecuado en un recipiente de reacción (ii) generar un aerosol en el recipiente de reacción (iii) cristalizar la sustancia y (iv) recuperando los cristales en el fondo del recipiente de reacción. El método es especialmente adecuado para cristalizar las sustancias que el son típicamente difícil cristalizar y el bote conducen a un resultado de la amplificación del quiral.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patentes con informe sobre el estado de la técnic

Impacts of Saharan Dust Intrusions on Bacterial Communities of the Low Troposphere

© The Author(s) 2020.We have analyzed the bacterial community of a large Saharan dust event in the Iberian Peninsula and, for the first time, we offer new insights regarding the bacterial distribution at different altitudes of the lower troposphere and the replacement of the microbial airborne structure as the dust event receeds. Samples from different open-air altitudes (surface, 100 m and 3 km), were obtained onboard the National Institute for Aerospace Technology (INTA) C-212 aircrafts. Samples were collected during dust and dust-free air masses as well two weeks after the dust event. Samples related in height or time scale seems to show more similar community composition patterns compared with unrelated samples. The most abundant bacterial species during the dust event, grouped in three different phyla: (a) Proteobacteria: Rhizobiales, Sphingomonadales, Rhodobacterales, (b) Actinobacteria: Geodermatophilaceae; (c) Firmicutes: Bacillaceae. Most of these taxa are well known for being extremely stress-resistant. After the dust intrusion, Rhizobium was the most abundant genus, (40–90% total sequences). Samples taken during the flights carried out 15 days after the dust event were much more similar to the dust event samples compared with the remaining samples. In this case, Brevundimonas, and Methylobacterium as well as Cupriavidus and Mesorizobium were the most abundant genera.This work was funded by the Spanish Economy and Competitiveness Ministry (MINECO) grants CGL2015-69758-P, CGL2017-92086-EXP, ESP2016-79612-C3-1-R, RTI2018-094867-BI00 and i-LINK 1151 grant founded by the Council for Scientific Research (CSIC). FPS was supported by the MINECO grant CTM2016-80095-C2-1-R