Influence of the long-range corrections on the interfacial properties of molecular models using Monte Carlo simulation

We analyze the influence of the long-range corrections, due to the dispersive term of the intermolecular potential energy, on the surface tension using direct simulation of the vapour-liquid interface of different molecular models. Although several calculation methods have been proposed recently to compute the fluid-fluid interfacial properties, the truncation of the intermolecular potential or the use of the tail corrections represents a contribution relevant from a quantitative perspective. In this work, a simplified model for methane, namely a spherical Lennard-Jones intermolecular potential, has been considered first, and afterwards other models including rigid non polarizable structures with both Lennard-Jones sites and point electric charges, representing some of the most popular models to describe water (namely the original TIP4P model, and the TIP4P/Ew and TIP4P/2005 versions), and carbon dioxide (MSM, EPM2, TraPPE, and ZD models) have been studied. Our results show that for all cases tested, including those in which the electrostatic interactions may be predominant, an incomplete account of the long-range corrections produces a systematic underestimation of the computed interfacial tension.The authors acknowledge CESGA (www.cesga.es), for providing access to computing facilities, and Consellería de Educación e Ordenación Universitaria (Xunta de Galicia) and Ministerio de Ciencia e Innovación (Grant Nos. FIS2009- 07923, FIS2010-14866, and FIS2012-33621, and FPU Grant No. AP2007-02172 for J.M.M.), in Spain, for financial support. Further financial support from Proyecto de Excelencia de la Junta de Andalucía (Grant No. P07-FQM02884) and Universidad de Huelva are also acknowledged

Molecular simulation of CO2 and H2 encapsulation in a nanoscale porous liquid

In this study we analyse from a theoretical perspective the encapsulation of both gaseous H2 and CO2 at different conditions of pressure and temperature in a Type II porous liquid, composed by nanometric scale cryptophane-111 molecules dispersed in dichloromethane, using atomistic molecular dynamics. Gaseous H2 tends to occupy cryptophane–111’s cavities in the early stages of the simulation; however, a remarkably greater selectivity of CO2 adsorption can be seen in the course of the simulation. Calculations were performed at ambient conditions first, and then varying temperature and pressure, obtaining some insight about the different adsorption found in each case. An evaluation of the host molecule cavities accessible volume was also performed, based on the guest that occupies the pore. Finally, a discussion between the different intermolecular host–guest interactions is presented, justifying the different selectivity obtained in the molecular simulation calculations. From the results obtained, the feasibility of a renewable separation and storage method for CO2 using these nanometric scale porous liquids is pointed out.Ministerio de Ciencia e Innovación | Ref. PID2021-125081NB-I0

A good equipment: The Outdoor Training and the rural tourism

[RESUMEN]Un buen equipo: El Outdoor Training y el turismo rural. El Outdoor Training es una herramienta innovadora que forja las relaciones relaciones de una forma profunda entre los empleados de la misma organización para que en la práctica se alcancen mayores niveles de productividad y una mayor satisfacción personal en el desempeño de sus funciones y mayor calidad en su día a día.sí mismo en el sector turístico los clientes cada día son más exigentes a la vez que los profesionales que se dedican a este campo se profesionalizan en más profundidad. Es por este motivo que los gerentes de casas rurales tienen la necesidad de conocer a sus clientes antes de que comiencen a disfrutar de su estancia en sus instalaciones.Las actividades que se realizan en un entorno natural, fuera del ámbito normal de trabajos hace que las relaciones sean más estrechas y la resolución de problemas es más eficaz. Ese entorno rural, es el que permite a los participantes que desconecten de los problemas diarios y haga que los participantes entren en contacto con la naturaleza mediante la realización de actividades de empresa, formación y turismo rural que hace que el aprendizaje perdure en el tiempo[ABSTRACT]Outdoor Training is an innovative tool that forging relationships relationships in a way deep between employees of the same organization in practice will achieve higher levels of productivity and a greater satisfaction in the performance of its functions and improved quality in their daily lives.Also in the tourism sector customers are demanding to professionals who are dedicated to this field Fundação in more depth. It is for this reason that bed and managers need to know their customers until they begin to enjoy their stay in their facilities.The activities that take place in a natural environment, outside the normal scope of work makes the relationships closer and problem solving is more effectiveThis rural environment, is that allows participants that disconnect from the everyday problems and make the participants to come into contact with nature through activities of company, training and rural tourism that makes learning to endure in tim

On interfacial tension calculation from the test-area methodology in the grand canonical ensemble

We propose the extension of the test-area methodology, originally proposed to evaluate the surface tension of planar fluid-fluid interfaces along a computer simulation in the canonical ensemble, to deal with the solid-fluid interfacial tension of systems adsorbed on slitlike pores using the grand canonical ensemble. In order to check the adequacy of the proposed extension, we apply the method for determining the density profiles and interfacial tension of spherical molecules adsorbed in slitlike pore with different pore sizes and solid-fluid dispersive energy parameters along the same simulation. We also calculate the solid-fluid interfacial tension using the original test-area method in the canonical ensemble. Agreement between the results obtained from both methods indicate that both methods are fully equivalent. The advantage of the new methodology is that allows to calculate simultaneously the density profiles and the amount of molecules adsorbed onto a slitlike pore, as well as the solid- fluid interfacial tension. This ensures that the chemical potential at which all properties are evaluated during the simulation is exactly the same since simulations can be performed in the grand canonical ensemble, mimicking the conditions at which the adsorption experiments are most usually carried out in the laboratory.The authors would like to acknowledge helpful discussions with B. Mendiboure. This work was supported by Ministerio de Ciencia e Innovación (MICINN, Spain) through Grant Nos. FIS2010-14866, FIS2009-07923, and FPU Ref. AP2007-02172 (J.M.M.). Further financial support from Proyecto de Excelencia from Junta de Andalucía (Grant No. P07-FQM02884) and Universidad de Huelva are also acknowledged

Adsorption and interfacial phenomena of a Lennard-Jones fluid adsorbed in slit pores: DFT and GCMC simulations

Confinement of fluids in porous media leads to the presence of solid–fluid (SF) interfaces that play a key role in many different fields. The experimental characterisation of SF interfacial properties, in par- ticular the surface tension, is challenging or not accessible. In this work, we apply mean-field density functional theory (DFT) to determine the surface tension and also density profile of a Lennard-Jones fluid in slit-shaped pores for realistic amounts of adsorbed molecules. We consider the pore walls to interact with fluid molecules through the well-known 10-4-3 Steele potential. The results are com- pared with those obtained from Monte Carlo simulations in the Grand Canonical Ensemble (GCMC) using the test-area method. We analyse the effect on the adsorption and interfacial phenomena of volume and energy factors, in particular, the pore diameter and the ratio between SF and fluid–fluid dispersive energy parameters, respectively. Results from DFT and GCMC simulations were found to be comparable, which points to their reliability.The authors would like to acknowledge helpful discussions with A. I. Moreno-Ventas Bravo. We also acknowledge Centro de Supercomputación de Galicia (CESGA, Santiago de Compostela, Spain) and MCIA (Mésocentre de Calcul Intensif Aquitain) of the Universités de Bordeaux and Pau et Pays de l’Adour (France), for providing access to computing facilities

Molecular simulation of methane hydrate growth confined into a silica pore

Financiaciado para publicación en acceso aberto: Universidade de Vigo/CISUGThe growth of a methane hydrate seed within a silica slit pore of fixed width has been studied using All- Atom Molecular Dynamics (AA-MD). An AA force field has been used to describe the molecules of the solid silica substrate, with a-quartz crystalline structure. The crystallisation of hydrates in confined geometries is not well understood yet, and the objective of this work is to study the hydrate growth inside a silica pore using molecular simulation. Both NVT and NpT ensembles were used in the AA-MD simulations to analyse the hydrate growth from an initial seed. Results showed that the boundary conditions imposed by the nanometric slit pore yielded a hydrate with structural defects, filling the accessible space between the silica walls. The water molecules which were not incorporated to the initial seed hydrate formed a high density water layer trapped between the silica walls and the crystallised hydrate. These results provide an interesting insight into the hydrate crystallisation process in confined geometries, resembling those found in natural hydrate deposits.Ministerio de Ciencia e Innovación | Ref. PID2021-125081NB-I00FEDER | Ref. SOE2/P1/P0823Xunta de Galicia | Ref. FSE-GALICIA 2014–2020Fundação para a Ciência e a Tecnologia | Ref. UIDB/50011/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/50011/2020Fundação para a Ciência e a Tecnologia | Ref. LA/ P/0006/2020Ministerio de Ciencia e Innovación | Ref. PID2019-105898GA-C22Comunidad de Madrid | Ref. APOYOJOVENES- 01HQ1S-129-B5E4M

An Examination of the Excess Thermodynamic Properties of Flexible Molecules from a Molecular Modelling Perspective

Excess thermodynamic properties provide fundamental information on the intermolecular interactions in multicomponent fluid mixtures. However, very often only phase equilibria is used to test the accuracy of any theory or molecular model describing the solution thermodynamic behaviour. Although this approach is valid and often sufficient, some situations require stronger tests to determine whether a model and/or theory can provide a realistic description of a particular system. Excess properties estimation is a valuable test for this purpose because excess properties are very sensitive to the molecular model details. The goal of this work is to show how simple models, with a reduced number of molecular parameters, are able to predict accurately excess thermodynamic properties. We concentrate on binary mixtures formed by different models of flexible molecules. In particular, we focus on two general models: the fully-flexible tangentially bonded Lennard–Jones chains model described with the SAFT VR [J. Chem. Phys. 106 (1997) 4168] approach, and the united-atom model combined with Monte Carlo simulation, in both cases applied to the description of short chain alkane mixtures (from methane to propane). While the first model does not consider intramolecular interactions and the bond length equals the monomer size, the second one incorporates a more realistic description. Although the molecular models are relatively simple, they are able to describe most of the microscopic features of real chainlike molecules. The predictions obtained from SAFT-VR and simulation are compared with available experimental data, and the agreement is good for a wide range of thermodynamic conditions. In addition to the vapour–liquid equilibria, both theory and simulation are able to characterize the most relevant features of two important excess thermodynamic properties, excess volume and enthalpy.We acknowledge financial support from project number FIS2011-13119-E, Red de Simulación Molecular (RdSiMol) of Sub- programa de Acciones Complementaria del Ministerio de Ciencia e Innovación. FJB acknowledges financial support from project number FIS2010-14866, and MMP from project FIS2012-33621 (this one co-financed with EU FEDER funds), both from of the Spanish Ministerio, Dirección de Ciencia e Innovación. Additional support from Universidad de Huelva and Junta de Andalucía is also acknowledged. MMP also acknowledges CESGA (www.cesga.es, Santiago de Compostela, Spain) for providing access to computing facilities

IC-Tagging methodology applied to the expression of viral glycoproteins and the difficult-to-express membrane-bound IGRP autoantigen

We have previously developed a methodology to produce protein microspheres (MS) that can be loaded with proteins of interest in living cells through their C or N-terminal tagging with the so-called IC-Tag. The IC-Tagging method has many applications ranging from the production of immobilized enzymes for industrial use to the production of subunit vaccines due to its intrinsic adjuvancy. Here we show the adaptation of the IC-Tagging to work inside the endoplasmic reticulum and bacteria, allowing us to produce properly modified viral glycoproteins. Additionally, we were able to express the Islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), whose expression remained elusive to date possibly due to its toxicity when over-expressed. IGRP is an antigen of enormous pharmaceutical interest as it is specifically targeted during the autoimmune response taking place in both the Non-Obese Diabetic (NOD) mice and type 1 diabetes (T1D) patients leading to the destruction of insulin-producing beta cellsThis work was financed by the Spanish Ministerio de Economía y Competitividad, grant BFU2013-43513-R. Financial support from the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016–2019) and the European Union (European Regional Development Fund - ERDF), is gratefully acknowledged. Irene Lostalé-Seijo was a recipient of a predoctoral FPU fellowship (Ministerio de Educación y Ciencia) and a Research Fellowship (Bolsa de Investigación; Deputación Provincial da Coruña)S

Vapor-liquid interfacial properties of rigid-linear Lennard-Jones chains

We have obtained the interfacial properties of short rigid-linear chains formed from tangentially bonded Lennard-Jones monomeric units from direct simulation of the vapour-liquid interface. The full long-range tails of the potential are accounted for by means of an improved version of the inhomogeneous long-range corrections of Janecek [J. Phys. Chem. B 110, 6264–6269 (2006)] proposed recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] valid for spherical as well as for rigid and flexible molecular systems. Three different model systems comprising of 3, 4, and 5 monomers per molecule are considered. The simulations are performed in the canonical ensemble, and the vapor-liquid interfacial tension is evaluated using the test-area method. In addition to the sur- face tension, we also obtain density profiles, coexistence densities, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the chain length and rigidity on these properties. According to our results, the main effect of increasing the chain length (at fixed temperature) is to sharpen the vapor-liquid interface and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness decreases and the sur- face tension increases as the molecular chains get longer. The surface tension has been scaled by critical properties and represented as a function of the difference between coexistence densities relative to the critical density.The authors would like to acknowledge helpful discus- sions with F. J. Martínez-Ruiz, E. de Miguel, C. Vega, and A. Galindo. This work was supported by Ministerio de Ciencia e Innovación (MICINN, Spain) through Grant Nos. FIS2010- 14866 (F.J.B.), FIS2009-07923 (J.M.M. and M.M.P.) and FIS2010-22047-C05-05 (L.G.M.D.). J.M.M. also acknowledges Ministerio de Ciencia e Innovación for the FPU Grant with reference AP2007-02172. Further financial support from Proyecto de Excelencia from Junta de Andalucía (Grant No. P07-FQM02884), Consellería de Educacion e Ordenacion Universitaria (Xunta de Galicia), Comunidad Autónoma de Madrid (Grant No. MODELICO-P2009/EPS-1691), and Universidad de Huelva are also acknowledged

Development and validation of a scale to assess Psychological Well-being in physical activity and sports: The PWBPA Scale

The aim of this study was to develop and validate a scale to assess psychological well-being in physical activity and sport context, based on Ryff's theory (2014) and the definition of psychological well-being proposed Piñeiro et.al (2021). For that purpose, a Likert type instrument with 51 items was designed. The scale was applied to 584 participants (63% women) with aged between 15 and 29 years (M=19.05;SD 2.97)), from secondary schools and universities from different autonomous communities of Spain. After the statistical analysis, eliminating the items with low values, the final instrument was composed with 40 items (6 dimensions). The results showed that the scale manifests high reliability (α= .965), as well as high levels of explained variance. In conclusion, the research provides a valuable instrument, supported by a scientific theoretical basis, for the evaluation of psychological well-being through physical activity and sports practice in Spanish youth. El objetivo de este estudio fue desarrollar y validar una escala para evaluar el bienestar psicológico en el contexto de la actividad física y el deporte, basándose en la teoría de Ryff (2014) y en la definición de bienestar psicológico propuesta por Piñeiro et al. (2021). Para dicho propósito, se diseñó un instrumento tipo Likert con 51 ítems. La escala fue aplicada a 584 participantes (63% mujeres) con edades entre los 15 y los 29 años (M=19.05) de escuelas secundarias y universidades de diferentes comunidades autónomas de España. Luego del análisis estadístico, eliminando ítems con bajos valores, el instrumento final quedo compuesto por 40 ítems (6 dimensiones). Los resultados muestran que la escala manifiesta alta fiabilidad, así como también altos niveles de varianza explicada. En conclusión, esta investigación provee un valioso instrumento, apoyado por una base teórica científica, para evaluar el bienestar psicológico a través de la práctica de la actividad física y el deporte en la juventud