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Antonio M. Puertas
Department of Economics and Business, University of Almeria, 04003 Almeria, Spain

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Journal article
Published: 18 May 2021 in Sustainability
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COVID-19 is certainly the first sustainability crisis of the 21st century. The paper examines the impact of COVID-19 on the Indian stock and commodity markets during the different phases of lockdown. In addition, the effect of COVID-19 on the Indian stock and commodity markets during the first and second waves of the COVID-19 spread was compared. A comparative analysis of the stock market performances and sustainability of selected South Asian countries is also included in the study, which covers the lockdown period as well as the time frame of the first and second waves of COVID-19 spread. To examine the above relationship, the conventional Welch test, heteroskedastic independent t-test, and the GMM multivariate analysis is employed, on the stock return, gold prices, and oil prices. The findings conclude that during the different phases of lockdown in India, COVID-19 has a negative and significant impact on oil prices and stock market performance. However, in terms of gold prices, the effect is positive and significant. The results of the first wave of COVID-19 infection also corroborate with the above findings. However, the results are contradictory during the second wave of coronavirus infection. Furthermore, the study also substantiates that COVID-19 has significantly affected the stock market performances of selected South Asian countries. However, the impact on the stock market performances was only for a short period and it diminished in the second wave of COVID-19 spread in all the selected South Asian countries. The findings contribute to the research on the stock and commodity market impact of a pandemic by providing empirical evidence that COVID-19 has spill-over effects on stock markets and commodity market performances. This result also helps investors in assessing the trends of the stock and commodity markets during the pandemic outbreak.

ACS Style

Farhan Ahmed; Aamir Syed; Muhammad Kamal; Maria De Las Nieves López-García; Jose Ramos-Requena; Swati Gupta. Assessing the Impact of COVID-19 Pandemic on the Stock and Commodity Markets Performance and Sustainability: A Comparative Analysis of South Asian Countries. Sustainability 2021, 13, 5669 .

AMA Style

Farhan Ahmed, Aamir Syed, Muhammad Kamal, Maria De Las Nieves López-García, Jose Ramos-Requena, Swati Gupta. Assessing the Impact of COVID-19 Pandemic on the Stock and Commodity Markets Performance and Sustainability: A Comparative Analysis of South Asian Countries. Sustainability. 2021; 13 (10):5669.

Chicago/Turabian Style

Farhan Ahmed; Aamir Syed; Muhammad Kamal; Maria De Las Nieves López-García; Jose Ramos-Requena; Swati Gupta. 2021. "Assessing the Impact of COVID-19 Pandemic on the Stock and Commodity Markets Performance and Sustainability: A Comparative Analysis of South Asian Countries." Sustainability 13, no. 10: 5669.

Journal article
Published: 11 March 2021 in Mathematics
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The volatility and log-price collective movements among stocks of a given market are studied in this work using co-movement functions inspired by similar functions in the physics of many-body systems, where the collective motions are a signal of structural rearrangement. This methodology is aimed to identify the cause of coherent changes in volatility or price. The function is calculated using the product of the variations in volatility (or price) of a pair of stocks, averaged over all pair particles. In addition to the global volatility co-movement, its distribution according to the volatility of the stocks is also studied. We find that stocks with similar volatility tend to have a greater co-movement than stocks with dissimilar volatility, with a general decrease in co-movement with increasing volatility. On the other hand, when the average volatility (or log-price) is subtracted from the stock volatility (or log-price), the co-movement decreases notably and becomes almost zero. This result, interpreted within the background of many body physics, allows us to identify the index motion as the main source for the co-movement. Finally, we confirm that during crisis periods, the volatility and log-price co-movement are much higher than in calmer periods.

ACS Style

María López-García; Miguel Sánchez-Granero; Juan Trinidad-Segovia; Antonio Puertas; Francisco De Las Nieves. Volatility Co-Movement in Stock Markets. Mathematics 2021, 9, 598 .

AMA Style

María López-García, Miguel Sánchez-Granero, Juan Trinidad-Segovia, Antonio Puertas, Francisco De Las Nieves. Volatility Co-Movement in Stock Markets. Mathematics. 2021; 9 (6):598.

Chicago/Turabian Style

María López-García; Miguel Sánchez-Granero; Juan Trinidad-Segovia; Antonio Puertas; Francisco De Las Nieves. 2021. "Volatility Co-Movement in Stock Markets." Mathematics 9, no. 6: 598.

Journal article
Published: 10 December 2020 in Sustainability
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This study aims to investigate the relationship between renewable energy consumption, water availability, and environmental degradation with the moderating effect of governance in the South Asian region. This study collected data for renewable energy, water availability, governance, and environmental degradation for the period of 1988 to 2018 from the World Development Indicator. In panel data estimation, if cross-sectional dependence exists, it produces biased estimates. Therefore, this study applied a newly developed technique, dynamic common correlated effect, which produces efficient estimates in the presence of cross-sectional dependence. This study found that foreign direct investment positively and significantly increases environment degradation (β = 0.69 *, * indicates the significance level at less than 1%) while renewable energy and water availability cause to reduce environment degradation (β = −0.08 **, β = −0.09 **, **indicates the significance level at less than 5%). Moreover, the study also found that governance significantly strengthens the relationship of renewable energy and water availability with environment degradation (β = 0.37 **, β = 0.24 **) while governance significantly weakens the relationship of foreign direct investment and environmental degradation (β = −0.34 *). The study suggests that South Asian countries should improve political institutions, and promote renewable energy, water availability, and clean production to improve the environment quality.

ACS Style

Shazia Kousar; Farhan Ahmed; María López García; Nimra Ashraf. Renewable Energy Consumption, Water Crises, and Environmental Degradation with Moderating Role of Governance: Dynamic Panel Analysis under Cross-Sectional Dependence. Sustainability 2020, 12, 10308 .

AMA Style

Shazia Kousar, Farhan Ahmed, María López García, Nimra Ashraf. Renewable Energy Consumption, Water Crises, and Environmental Degradation with Moderating Role of Governance: Dynamic Panel Analysis under Cross-Sectional Dependence. Sustainability. 2020; 12 (24):10308.

Chicago/Turabian Style

Shazia Kousar; Farhan Ahmed; María López García; Nimra Ashraf. 2020. "Renewable Energy Consumption, Water Crises, and Environmental Degradation with Moderating Role of Governance: Dynamic Panel Analysis under Cross-Sectional Dependence." Sustainability 12, no. 24: 10308.

Journal article
Published: 30 October 2020 in Energies
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The important topic of modelling tanks filled with phase change materials (PCMs) is discussed in this article. Due to the increasing use of heating and cooling installations, tanks containing two types of PCMs are the subject of many experimental analyses. However, there are still deficiencies in their models, which are presented in this paper. The theory model was created in order to design two tanks, each with a volume of 2 m3. They were filled with water and containers with two PCMs. The modelled tanks were meant to replace the existing water tanks that were previously used in the solar heating and cooling installation in a research building located in the southern part of Spain. After the tanks were assembled, the model was validated during the summer period when the designed storage tanks supported the operation of the solar system operating in the cooling mode. The created model consists of a 1D description of the heat transfer in the storage tank, and also a 1D description of the phase change in the containers with the PCMs. The model takes into account the front of the phase change and also discusses its impact on the thermal efficiency of the tanks. The agreement of the water output temperature is very good and validates the model, which can then be used to provide further details on the operation of the storage system—in particular, heat fluxes or a fraction of solid or liquid PCM.

ACS Style

Artur Nemś; Antonio M. Puertas. Model for the Discharging of a Dual PCM Heat Storage Tank and its Experimental Validation. Energies 2020, 13, 5687 .

AMA Style

Artur Nemś, Antonio M. Puertas. Model for the Discharging of a Dual PCM Heat Storage Tank and its Experimental Validation. Energies. 2020; 13 (21):5687.

Chicago/Turabian Style

Artur Nemś; Antonio M. Puertas. 2020. "Model for the Discharging of a Dual PCM Heat Storage Tank and its Experimental Validation." Energies 13, no. 21: 5687.

Journal article
Published: 29 August 2020 in Entropy
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One of the main contributions of the Capital Assets Pricing Model (CAPM) to portfolio theory was to explain the correlation between assets through its relationship with the market index. According to this approach, the market index is expected to explain the co-movement between two different stocks to a great extent. In this paper, we try to verify this hypothesis using a sample of 3.000 stocks of the USA market (attending to liquidity, capitalization, and free float criteria) by using some functions inspired by cooperative dynamics in physical particle systems. We will show that all of the co-movement among the stocks is completely explained by the market, even without considering the market beta of the stocks.

ACS Style

Antonio Manuel Puertas López; Miguel Sánchez-Granero; Juan Trinidad-Segovia; Antonio Puertas; Francisco Nieves. A New Look on Financial Markets Co-Movement through Cooperative Dynamics in Many-Body Physics. Entropy 2020, 22, 954 .

AMA Style

Antonio Manuel Puertas López, Miguel Sánchez-Granero, Juan Trinidad-Segovia, Antonio Puertas, Francisco Nieves. A New Look on Financial Markets Co-Movement through Cooperative Dynamics in Many-Body Physics. Entropy. 2020; 22 (9):954.

Chicago/Turabian Style

Antonio Manuel Puertas López; Miguel Sánchez-Granero; Juan Trinidad-Segovia; Antonio Puertas; Francisco Nieves. 2020. "A New Look on Financial Markets Co-Movement through Cooperative Dynamics in Many-Body Physics." Entropy 22, no. 9: 954.

Journal article
Published: 29 July 2020 in Energies
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An important element of a solar installation is the storage tank. When properly selected and operated, it can bring numerous benefits. The presented research relates to a project that is implemented at the Solar Energy Research Center of the University of Almeria in Spain. In order to improve the operation of the solar cooling and heating system of the Center, it was upgraded with two newly designed storage tanks filled with phase change materials (PCM). As a result of design works, commercial material S10 was selected for the accumulation of cold, and S46 for the accumulation of heat, in an amount of 85% and 15%, respectively. The article presents in detail the process of selecting the PCM material, designing the installation, experimental research, and exergy analysis. Individual tasks were carried out by research groups cooperating under the PCMSOL EUROPEAN PROJECT. Results of tests conducted on the constructed installation indicate that daily energy saving when using a solar chiller with PCM tanks amounts to 40% during the cooling season.

ACS Style

F. Javier Batlles; Bartosz Gil; Svetlana Ushak; Jacek Kasperski; Marcos Luján; Diana Maldonado; Magdalena Nemś; Artur Nemś; Antonio M. Puertas; Manuel S. Romero-Cano; Sabina Rosiek; Mario Grageda. Development and Results from Application of PCM-Based Storage Tanks in a Solar Thermal Comfort System of an Institutional Building—A Case Study. Energies 2020, 13, 3877 .

AMA Style

F. Javier Batlles, Bartosz Gil, Svetlana Ushak, Jacek Kasperski, Marcos Luján, Diana Maldonado, Magdalena Nemś, Artur Nemś, Antonio M. Puertas, Manuel S. Romero-Cano, Sabina Rosiek, Mario Grageda. Development and Results from Application of PCM-Based Storage Tanks in a Solar Thermal Comfort System of an Institutional Building—A Case Study. Energies. 2020; 13 (15):3877.

Chicago/Turabian Style

F. Javier Batlles; Bartosz Gil; Svetlana Ushak; Jacek Kasperski; Marcos Luján; Diana Maldonado; Magdalena Nemś; Artur Nemś; Antonio M. Puertas; Manuel S. Romero-Cano; Sabina Rosiek; Mario Grageda. 2020. "Development and Results from Application of PCM-Based Storage Tanks in a Solar Thermal Comfort System of an Institutional Building—A Case Study." Energies 13, no. 15: 3877.

Article
Published: 18 May 2020 in Physical Review E
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The analysis of the dynamics of tracer particles in a complex bath can provide valuable information about the microscopic behavior of the bath. In this work, we study the dynamics of a forced tracer in a colloidal bath by means of Langevin dynamics simulations and a theory model within continuum mechanics. In the simulations, the bath is comprised of quasihard spheres with a volume fraction of 50% immersed in a featureless quiescent solvent, and the tracer is pulled with a constant small force (within the linear regime). The theoretical analysis is based on the Navier-Stokes equation, where a term proportional to the velocity arises from coarse-graining the friction of the colloidal particles with the solvent. As a result, the final equation is similar to the Brinkman model, although the interpretation is different. A length scale appears in the model, k0−1, where the transverse momentum transport crosses over to friction with the solvent. The effective friction coefficient experienced by the tracer grows with the tracer size faster than the prediction from Stokes's law. Additionally, the velocity profiles in the bath decay faster than in a Newtonian fluid. The comparison between simulations and theory points to a boundary condition of effective partial slip at the tracer surface. We also study the fluctuations in the tracer position, showing that it reaches diffusion at long times, with a subdiffusive regime at intermediate times. The diffusion coefficient, obtained from the long-time slope of the mean-squared displacement, fulfills the Stokes-Einstein relation with the friction coefficient calculated from the steady tracer velocity, confirming the validity of the linear response formalism.

ACS Style

F. Orts; G. Ortega; E. M. Garzón; M. Fuchs; A. M. Puertas. Dynamics and friction of a large colloidal particle in a bath of hard spheres: Langevin dynamics simulations and hydrodynamic description. Physical Review E 2020, 101, 052607 .

AMA Style

F. Orts, G. Ortega, E. M. Garzón, M. Fuchs, A. M. Puertas. Dynamics and friction of a large colloidal particle in a bath of hard spheres: Langevin dynamics simulations and hydrodynamic description. Physical Review E. 2020; 101 (5):052607.

Chicago/Turabian Style

F. Orts; G. Ortega; E. M. Garzón; M. Fuchs; A. M. Puertas. 2020. "Dynamics and friction of a large colloidal particle in a bath of hard spheres: Langevin dynamics simulations and hydrodynamic description." Physical Review E 101, no. 5: 052607.

Article
Published: 17 March 2020 in Physical Review E
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Different attempts to describe financial markets, and stock prices in particular, with the tools of statistical mechanics can be found in the literature, although a general framework has not been achieved yet. In this paper we use the physics of many-particle systems and the typical concepts of soft matter to study two sets of US and European stocks, comprising the biggest and most stable companies in terms of stock price and trading. Upon correcting for the center-of-mass motion, the structure and dynamics of the systems are studied (in the European set, the structure is studied for the UK subset only). The pair distribution of the stocks, corrected to account for the nonuniform distribution of prices, is close to 1, indicating that there is no direct interaction between stocks, similar to an ideal gas of particles. The dynamics is studied with the mean-squared price displacement (MSPD); the price correlation function, equivalent to the intermediate scattering function; the price fluctuation distribution; and two parameters for collective motions. The MSPD grows linearly and the velocity autocorrelation function is zero, as for isolated Brownian particles. However, the intermediate scattering function follows a stretched exponential decay, the fluctuation distributions deviate from the Gaussian shape, and strong collective motions are identified. These results indicate that the dynamics is much more complex than an ideal gas of Brownian particles, and similar, to some extent, to that of undercooled systems. Finally, two physical systems are discussed to aid in the understanding of these results: a low density colloidal gel, and a dense system of ideal, infinitely thin stars. The former reproduces the dynamical properties of stocks, linear mean-squared displacement (MSD), non-Gaussian fluctuation distribution, and collective motions, but also has strong structural correlations, whereas the latter undergoes a glass transition with the structure of an ideal gas, but the MSD has the typical two-step growth of undercooled systems.

ACS Style

Antonio M. Puertas; Miguel A. Sánchez-Granero; Joaquim Clara-Rahola; Juan E. Trinidad-Segovia; F. Javier De Las Nieves. Stock markets: A view from soft matter. Physical Review E 2020, 101, 032307 .

AMA Style

Antonio M. Puertas, Miguel A. Sánchez-Granero, Joaquim Clara-Rahola, Juan E. Trinidad-Segovia, F. Javier De Las Nieves. Stock markets: A view from soft matter. Physical Review E. 2020; 101 (3):032307.

Chicago/Turabian Style

Antonio M. Puertas; Miguel A. Sánchez-Granero; Joaquim Clara-Rahola; Juan E. Trinidad-Segovia; F. Javier De Las Nieves. 2020. "Stock markets: A view from soft matter." Physical Review E 101, no. 3: 032307.

Erratum
Published: 13 May 2019 in The Journal of Chemical Physics
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ACS Style

Antonio M. Puertas; Paolo Malgaretti; Ignacio Pagonabarraga. Erratum: “Active microrheology in corrugated channels” [J. Chem. Phys. 149, 174908 (2018)]. The Journal of Chemical Physics 2019, 150, 189901 .

AMA Style

Antonio M. Puertas, Paolo Malgaretti, Ignacio Pagonabarraga. Erratum: “Active microrheology in corrugated channels” [J. Chem. Phys. 149, 174908 (2018)]. The Journal of Chemical Physics. 2019; 150 (18):189901.

Chicago/Turabian Style

Antonio M. Puertas; Paolo Malgaretti; Ignacio Pagonabarraga. 2019. "Erratum: “Active microrheology in corrugated channels” [J. Chem. Phys. 149, 174908 (2018)]." The Journal of Chemical Physics 150, no. 18: 189901.

Article
Published: 03 November 2017 in Journal of Biomedical Materials Research Part B: Applied Biomaterials
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Porous ceramics doped with silicon and pure β-TCP were analyzed in terms of internal microstructure, cell behavior, and the percentage of newly formed bone. Additionally the materials were tested to determine which of the two had better properties to load and release vancomycin hydrochloride. Internal pore distribution and porosity were determined through high pressure mercury porosimetry and the specific surface area was measured by the Brunauer Emmet-Teller method. The proliferation and viability of the human osteoblast-like cell line MG-63 was studied to validate both materials. The materials were tested on eight New Zealand rabbits which created defects, 10 mm in diameter, in the calvaria bone. After 8 and 12 weeks a histological and histomorphometric analysis was performed. Si-β-TCP showed a higher porosity and specific surface area. The cytocompatibility test revealed acceptable results in terms of proliferation and viability whereas the percentage of new bone was higher in Si-β-TCP with a two-time study being statistically significant with 12 weeks of healing (p < 0.05).The vancomycin loaded within the ceramic scaffolds were burst released and the material had the ability to inhibit bacterial growth. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017.

ACS Style

Angel Manchón; Mohammad H. Alkhraisat; Carmen Rueda-Rodriguez; Concepción Pintado; J.C. Prados-Frutos; Jesus Torres; Enrique Lopez Cabarcos. Silicon bioceramic loaded with vancomycin stimulates bone tissue regeneration. Journal of Biomedical Materials Research Part B: Applied Biomaterials 2017, 106, 2307 -2315.

AMA Style

Angel Manchón, Mohammad H. Alkhraisat, Carmen Rueda-Rodriguez, Concepción Pintado, J.C. Prados-Frutos, Jesus Torres, Enrique Lopez Cabarcos. Silicon bioceramic loaded with vancomycin stimulates bone tissue regeneration. Journal of Biomedical Materials Research Part B: Applied Biomaterials. 2017; 106 (6):2307-2315.

Chicago/Turabian Style

Angel Manchón; Mohammad H. Alkhraisat; Carmen Rueda-Rodriguez; Concepción Pintado; J.C. Prados-Frutos; Jesus Torres; Enrique Lopez Cabarcos. 2017. "Silicon bioceramic loaded with vancomycin stimulates bone tissue regeneration." Journal of Biomedical Materials Research Part B: Applied Biomaterials 106, no. 6: 2307-2315.

Review
Published: 01 November 2017 in Advances in Colloid and Interface Science
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In recent years, considerable efforts have been done to better understand the peculiar emission properties of upconverting materials due to their widespread applications in different and important technological fields such as upconversion-based photoactivated cancer therapies, photoactivated drug-delivery, magnetic resonance imaging contrast agents, bioimaging. However, one of the most promising applications of upconverting materials concerns the field of sensing, due to their unique emission properties. In fact, the minimal autofluorescence, blinking, photo-bleaching, and high photostability makes them an excellent alternative to organic dyes or quantum dots. This article reviews the state-of-the-art, design, and sensing strategies of upconversion-based sensing platforms, with special attention to upconverting nanoparticles, as well as how the incorporation of these materials into pre-existing diagnostic tests and bioassays have improved their capabilities for the detection of different kinds of analytes.

ACS Style

Diego Méndez González; Enrique Lopez-Cabarcos; Jorge Rubio-Retama; Marco Laurenti. Sensors and bioassays powered by upconverting materials. Advances in Colloid and Interface Science 2017, 249, 66 -87.

AMA Style

Diego Méndez González, Enrique Lopez-Cabarcos, Jorge Rubio-Retama, Marco Laurenti. Sensors and bioassays powered by upconverting materials. Advances in Colloid and Interface Science. 2017; 249 ():66-87.

Chicago/Turabian Style

Diego Méndez González; Enrique Lopez-Cabarcos; Jorge Rubio-Retama; Marco Laurenti. 2017. "Sensors and bioassays powered by upconverting materials." Advances in Colloid and Interface Science 249, no. : 66-87.

Article
Published: 01 May 2017 in Physical Review E
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The equilibrium structure and dynamics of magnetorheological (MR) fluids are studied in this work by simulations, where particles are modeled as dipoles with a quasihard spherical core. Upon increasing the interaction strength, controlled experimentally by the magnetic field, elongated clusters grow and, for intense fields, thick columns form, aligned with the field. The dynamics of the system is monitored by the mean-squared displacement and density correlation functions, which show an increasing slowing down with the attraction strength. The correlation function shows a two-step decay, with a separation between microscopic and long time dynamics, a typical hallmark of undercooled fluids. We have therefore analyzed the dynamics of this MR fluid using the typical concepts for undercooled fluids. Thus, the second decay of the density correlation function is fitted with a stretched exponential, and the wave-vector dependence of the fitting parameters studied. Both the amplitude and the time scale oscillate in phase with the structure factor. Our results support the idea that the magnetorheological effect is in fact the manifestation of a colloidal system approaching an attractive glass transition (or gel transition).

ACS Style

J. P. Segovia-Gutiérrez; J. de Vicente; Antonio M. Puertas; R. Hidalgo-Alvarez. Describing magnetorheology under a colloidal glass approach. Physical Review E 2017, 95, 052601 -052601.

AMA Style

J. P. Segovia-Gutiérrez, J. de Vicente, Antonio M. Puertas, R. Hidalgo-Alvarez. Describing magnetorheology under a colloidal glass approach. Physical Review E. 2017; 95 (5):052601-052601.

Chicago/Turabian Style

J. P. Segovia-Gutiérrez; J. de Vicente; Antonio M. Puertas; R. Hidalgo-Alvarez. 2017. "Describing magnetorheology under a colloidal glass approach." Physical Review E 95, no. 5: 052601-052601.

Journal article
Published: 21 April 2017 in Energies
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We present in this work simulations using the finite difference approximation in 2D for the melting of an encapsulated phase-change material suitable for heat storage applications; in particular, we study CaCl2·6H2O in a cylindrical encapsulation of internal radius 8 mm. We choose this particular salt hydrate due to its availability and economic feasibility in high thermal mass building walls or storage. Considering only heat conduction, a thermostat is placed far from the capsule, providing heat for the melting of the phase-change material (PCM), which is initially frozen in a water bath. The difference in density between the solid and liquid phases is taken into account by considering a void in the solid PCM. A simple theoretical model is also presented, based on solving the heat equation in the steady state. The kinetics of melting is monitored by the total solid fraction and temperatures in the inner and outer surfaces of the capsule. The effect of different parameters is presented (thermostat temperature, capsule thickness, capsule conductivity and natural convection in the bath), showing the potential application of the method to select materials or geometries of the capsule.

ACS Style

Antonio M. Puertas; Manuel S. Romero-Cano; Francisco Javier De Las Nieves; Sabina Rosiek; Francisco J. Batlles. Simulations of Melting of Encapsulated CaCl2·6H2O for Thermal Energy Storage Technologies. Energies 2017, 10, 568 .

AMA Style

Antonio M. Puertas, Manuel S. Romero-Cano, Francisco Javier De Las Nieves, Sabina Rosiek, Francisco J. Batlles. Simulations of Melting of Encapsulated CaCl2·6H2O for Thermal Energy Storage Technologies. Energies. 2017; 10 (4):568.

Chicago/Turabian Style

Antonio M. Puertas; Manuel S. Romero-Cano; Francisco Javier De Las Nieves; Sabina Rosiek; Francisco J. Batlles. 2017. "Simulations of Melting of Encapsulated CaCl2·6H2O for Thermal Energy Storage Technologies." Energies 10, no. 4: 568.

Article
Published: 10 February 2017 in Physical Review Letters
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This work studies the symmetry between colloidal dynamics and the dynamics of the Euro–U.S. dollar currency exchange market (EURUSD). We consider the EURUSD price in the time range between 2001 and 2015, where we find significant qualitative symmetry between fluctuation distributions from this market and the ones belonging to colloidal particles in supercooled or arrested states. In particular, we find that models used for arrested physical systems are suitable for describing the EURUSD fluctuation distributions. Whereas the corresponding mean-squared price displacement (MSPD) to the EURUSD is diffusive for all years, when focusing in selected time frames within a day, we find a two-step MSPD when the New York Stock Exchange market closes, comparable to the dynamics in supercooled systems. This is corroborated by looking at the price correlation functions and non-Gaussian parameters and can be described by the theoretical model. We discuss the origin and implications of this analogy. DOI:https://doi.org/10.1103/PhysRevLett.118.068301 © 2017 American Physical Society

ACS Style

J. Clara-Rahola; A. M. Puertas; M. A. Sánchez-Granero; J. E. Trinidad-Segovia; F. J. De Las Nieves. Diffusive and Arrestedlike Dynamics in Currency Exchange Markets. Physical Review Letters 2017, 118, 1 .

AMA Style

J. Clara-Rahola, A. M. Puertas, M. A. Sánchez-Granero, J. E. Trinidad-Segovia, F. J. De Las Nieves. Diffusive and Arrestedlike Dynamics in Currency Exchange Markets. Physical Review Letters. 2017; 118 (6):1.

Chicago/Turabian Style

J. Clara-Rahola; A. M. Puertas; M. A. Sánchez-Granero; J. E. Trinidad-Segovia; F. J. De Las Nieves. 2017. "Diffusive and Arrestedlike Dynamics in Currency Exchange Markets." Physical Review Letters 118, no. 6: 1.

Journal article
Published: 01 April 2016 in Materials Science and Engineering: C
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Staphylococcus aureus is the most relevant pathogen associated with bone infection that sometimes appears after implant surgery, thus compromising a successful treatment. The aim of this work was to assess the effectiveness of brushite cements, doped with magnesium, as a new vancomycin carrier system against S.aureus infections. We performed an "in vitro" study to evaluate vancomycin release from the cements by measuring its antimicrobial activity against a strain of S.aureus. We have used two methods to load the cements with vancomycin: i) adsorption from a solution and ii) incorporation of the antibiotic into the solid phase during the cement synthesis. Furthermore, the compression strength of the loaded samples was measured to detect changes in the mechanical properties of the system. The "in vitro" study showed that the sustained release of vancomycin depends on the concentration of magnesium in the cement matrix. In addition, the standardized antibacterial assay revealed that the release of vancomycin from the cements may be helpful to prevent infections in bone regeneration procedures.

ACS Style

Jatsue Cabrejos-Azama; Mohammad Alkhraisat; Carmen Rueda; Jesus Torres; Concepción Pintado; Luis Blanco; Enrique López-Cabarcos. Magnesium substitution in brushite cements: Efficacy of a new biomaterial loaded with vancomycin for the treatment of Staphylococcus aureus infections. Materials Science and Engineering: C 2016, 61, 72 -78.

AMA Style

Jatsue Cabrejos-Azama, Mohammad Alkhraisat, Carmen Rueda, Jesus Torres, Concepción Pintado, Luis Blanco, Enrique López-Cabarcos. Magnesium substitution in brushite cements: Efficacy of a new biomaterial loaded with vancomycin for the treatment of Staphylococcus aureus infections. Materials Science and Engineering: C. 2016; 61 ():72-78.

Chicago/Turabian Style

Jatsue Cabrejos-Azama; Mohammad Alkhraisat; Carmen Rueda; Jesus Torres; Concepción Pintado; Luis Blanco; Enrique López-Cabarcos. 2016. "Magnesium substitution in brushite cements: Efficacy of a new biomaterial loaded with vancomycin for the treatment of Staphylococcus aureus infections." Materials Science and Engineering: C 61, no. : 72-78.

Journal article
Published: 01 July 2015 in Materials Research Express
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Paulino Alonso-Cristobal; Marco Laurenti; Enrique Lopez-Cabarcos; Jorge Rubio-Retama. Efficient synthesis of [email protected] [email protected] nanoparticles. Materials Research Express 2015, 2, 1 .

AMA Style

Paulino Alonso-Cristobal, Marco Laurenti, Enrique Lopez-Cabarcos, Jorge Rubio-Retama. Efficient synthesis of [email protected] [email protected] nanoparticles. Materials Research Express. 2015; 2 (7):1.

Chicago/Turabian Style

Paulino Alonso-Cristobal; Marco Laurenti; Enrique Lopez-Cabarcos; Jorge Rubio-Retama. 2015. "Efficient synthesis of [email protected] [email protected] nanoparticles." Materials Research Express 2, no. 7: 1.

Journal article
Published: 01 February 2015 in Journal of Colloid and Interface Science
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We study by computer simulations the interaction between two similarly charged colloidal particles confined between parallel planes, in salt free conditions. Both the colloids and ions are simulated explicitly, in a fine-mesh lattice, and the electrostatic interaction is calculated using Ewald summation in two dimensions. The internal energy is measured by setting the colloidal particles at a given position and equilibrating the ions, whereas the free energy is obtained introducing a bias (attractive) potential between the colloids. Our results show that upon confining the system, the internal energy decreases, resulting in an attractive contribution to the interaction potential for large charges and strong confinement. However, the loss of entropy of the ions is the dominant mechanism in the interaction, irrespective of the confinement of the system. The interaction potential is therefore repulsive in all cases, and is well described by the DLVO functional form, but effective values have to be used for the interaction strength and Debye length.

ACS Style

Antonio M. Puertas; F. Javier De Las Nieves; Alejandro Cuetos. Computer simulations of charged colloids in confinement. Journal of Colloid and Interface Science 2015, 440, 292 -298.

AMA Style

Antonio M. Puertas, F. Javier De Las Nieves, Alejandro Cuetos. Computer simulations of charged colloids in confinement. Journal of Colloid and Interface Science. 2015; 440 ():292-298.

Chicago/Turabian Style

Antonio M. Puertas; F. Javier De Las Nieves; Alejandro Cuetos. 2015. "Computer simulations of charged colloids in confinement." Journal of Colloid and Interface Science 440, no. : 292-298.

Journal article
Published: 01 October 2014 in Materials Science and Engineering: C
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We have synthesized calcium phosphate cements doped with different amounts of magnesium (Mg-CPC)with a twofold purpose: i)to evaluate in vitro the osteoblast cell response to this material and ii) to compare the bone regeneration capacity of the doped material with a calcium cement prepared without magnesium (CPC). Cell proliferation and in vivo response increased in the Mg-CPC's in comparison with CPC. The Mg-CPC's have promoted higher new bone formation than the CPC (p<0.05). The cytocompatibility and histomorfometric analysis performed in the rabbit calvaria showed that the incorporation of magnesium ions in CPC improves osteoblasts proliferation and provides higher new bone formation. The development of a bone substitute with controllable biodegradable properties and improved bone regeneration can be considered a step toward personalized therapy that can adapt to patient needs and clinical situations

ACS Style

Jatsue Cabrejos-Azama; Mohammad Alkhraisat; Carmen Rueda; Jesus Torres; Luis Blanco; Enrique López-Cabarcos. Magnesium substitution in brushite cements for enhanced bone tissue regeneration. Materials Science and Engineering: C 2014, 43, 403 -410.

AMA Style

Jatsue Cabrejos-Azama, Mohammad Alkhraisat, Carmen Rueda, Jesus Torres, Luis Blanco, Enrique López-Cabarcos. Magnesium substitution in brushite cements for enhanced bone tissue regeneration. Materials Science and Engineering: C. 2014; 43 ():403-410.

Chicago/Turabian Style

Jatsue Cabrejos-Azama; Mohammad Alkhraisat; Carmen Rueda; Jesus Torres; Luis Blanco; Enrique López-Cabarcos. 2014. "Magnesium substitution in brushite cements for enhanced bone tissue regeneration." Materials Science and Engineering: C 43, no. : 403-410.

Journal article
Published: 18 September 2014 in Physical Review Letters
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We report the specific heat cN around the melting transition(s) of micrometer-sized superparamagnetic particles confined in two dimensions, calculated from fluctuations of positions and internal energy, and corresponding Monte Carlo simulations. Since colloidal systems provide single particle resolution, they offer the unique possibility to compare the experimental temperatures of the peak position of cN(T) and symmetry breaking, respectively. While order parameter correlation functions confirm the Kosterlitz-Thouless-Halperin-Nelson-Young melting scenario where translational and orientational order symmetries are broken at different temperatures with an intermediate so called hexatic phase, we observe a single peak of the specific heat within the hexatic phase, with excellent agreement between experiment and simulation. Thus, the peak is not associated with broken symmetries but can be explained with the total defect density, which correlates with the maximum increase of isolated dislocations. The absence of a latent heat strongly supports the continuous character of both transitions.

ACS Style

Sven Deutschländer; Antonio M. Puertas; Georg Maret; Peter Keim; Antonio Manuel Puertas López. Specific Heat in Two-Dimensional Melting. Physical Review Letters 2014, 113, 1 .

AMA Style

Sven Deutschländer, Antonio M. Puertas, Georg Maret, Peter Keim, Antonio Manuel Puertas López. Specific Heat in Two-Dimensional Melting. Physical Review Letters. 2014; 113 (12):1.

Chicago/Turabian Style

Sven Deutschländer; Antonio M. Puertas; Georg Maret; Peter Keim; Antonio Manuel Puertas López. 2014. "Specific Heat in Two-Dimensional Melting." Physical Review Letters 113, no. 12: 1.

Journal article
Published: 01 September 2014 in Materials Science and Engineering: C
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The present paper describes the synthesis and characterization of a new polymeric biomaterial mineralized with calcium phosphate using the reaction-diffusion method. The scaffold of this biomaterial was a hydrogel constituted by biocompatible polyethylene glycol methyl ether methacrylate (PEGMEM) and 2-(dimethylamino)ethyl methacrylate (DMAEM), which were cross-linked with N-N'-methylenebisacrylamide (BIS). The cross-linking content of the hydrogels was varied from 0.25% to 15% (w/w). The gels were used as matrix where two reactants (Na2HPO4 and CaCl2) diffused from both ends of the gel and upon encountering produced calcium phosphate crystals that precipitated within the polymer matrix forming bands. The shape of the crystals was tuned by modifying the matrix porosity in such a way that when the polymer matrix was slightly reticulated the diffusion reaction produced round calcium phosphate microcrystals, whilst when the polymer matrix was highly reticulated the reaction yielded flat calcium phosphate crystals. Selected area electron diffraction performed on the nanocrystals that constitute the microcrystals showed that they were formed by Brushite (CaHPO4.2H2O). This new composite material could be useful in medical and dentistry applications such as bone regeneration, bone repair or tissue engineering.

ACS Style

Yousof Ramadan; Maria Isabel Gonzalez Sanchez; Karl Hawkins; Jorge Rubio-Retama; Edelmira Valero; Stefano Perni; Polina Prokopovich; Enrique López-Cabarcos. Obtaining new composite biomaterials by means of mineralization of methacrylate hydrogels using the reaction–diffusion method. Materials Science and Engineering: C 2014, 42, 696 -704.

AMA Style

Yousof Ramadan, Maria Isabel Gonzalez Sanchez, Karl Hawkins, Jorge Rubio-Retama, Edelmira Valero, Stefano Perni, Polina Prokopovich, Enrique López-Cabarcos. Obtaining new composite biomaterials by means of mineralization of methacrylate hydrogels using the reaction–diffusion method. Materials Science and Engineering: C. 2014; 42 ():696-704.

Chicago/Turabian Style

Yousof Ramadan; Maria Isabel Gonzalez Sanchez; Karl Hawkins; Jorge Rubio-Retama; Edelmira Valero; Stefano Perni; Polina Prokopovich; Enrique López-Cabarcos. 2014. "Obtaining new composite biomaterials by means of mineralization of methacrylate hydrogels using the reaction–diffusion method." Materials Science and Engineering: C 42, no. : 696-704.