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Papers by Adrian Rafael Reyes

Journal of Bacteriology, 2017

Gram-positive bacteria utilize exported peptides to coordinate genetic and physiological processe... more Gram-positive bacteria utilize exported peptides to coordinate genetic and physiological processes required for biofilm formation, stress responses and ecological competitiveness. One example is activation of natural genetic competence by ComR and the com X - i nducing p eptide (XIP) in Streptococcus mutans . Although the competence pathway can be activated by addition of synthetic XIP in defined medium, the hypothesis that XIP is able to function as an intercellular signal molecule has not been rigorously tested. Co-culture model systems were developed that included a “sender” strain that overexpressed the XIP precursor (ComS) and a “responder” strain harboring a GFP reporter fusion to a ComR-activated gene ( comX ) promoter. The ability of the sender strain to provide a signal to activate GFP expression was monitored at the individual cell and population levels using i) planktonic culture systems, ii) cells suspended in an agarose matrix or iii) cells growing in biofilms. XIP was ...

Bulletin of the American Physical Society, Mar 5, 2015

heat to create a combustion front that raises the fuel temperature, decreasing its viscosity, mak... more heat to create a combustion front that raises the fuel temperature, decreasing its viscosity, making extraction easier. The oil is taken toward the productor by means of a vigorous gas thrust as well as a water thrust. To improve and enhance this technique in the field wells, it has been widely perform experimental laboratory tests, in which an in-situ combustion tube is designed to simulate the extraction process. In the present work we propose to solve analytically the problem, with a parabolic partial differential equation associated to the convection-diffusion phenomenon, equation which describes the in-situ combustion process. The whole mathematical problem is established by completing this equation with the correspong boundary and initial conditions, the thickness of the combustion zone, flow velocity, and more parameters. The theoretically obtained results are compared with those reported in literature. We further, fit the parameter of our model to the mentioned data taken from the literature.

Bulletin of the American Physical Society, Mar 4, 2015

Submitted for the MAR15 Meeting of The American Physical Society Biviscous blood flow and a new m... more Submitted for the MAR15 Meeting of The American Physical Society Biviscous blood flow and a new method for velocity profile adjustment CARLOS VELAZQUEZ, ADRIAN REYES, Universidad Nacional Autonoma de Mexico-In this paper we describe our proposal of a new numerical procedure for the adjusting of the velocity profile of body fluids with two viscosities. We have focused on the relevant case of the human blood and we have selected a particular model, the biviscous blood model, with the purpose of proving the convenience of our method. We start by describing the convenience of the biviscous stress equation as a model for the blood constitutive equation, then we solve it in the particular case of a stationary flow and use this solutions as the basis of our numerical procedure, which is described afterwards. Then, we present its implementation for analyzing in vivo measurements and exhibit its pertinence. Finally, we explain the design of a programmatic code of an automatic routine which is capable of applying our method and therefore could be used as the basis of an automatic implementation in new diagnosis software within a measurement device.

Inter Press Service English News Wire, Mar 29, 2005

Saguntum Papeles Del Laboratorio De Arqueologia De Valencia, 2014

Sagvntvm Papeles Del Laboratorio De Arqueologia De Valencia, Aug 9, 2011

Bulletin of the American Physical Society, Mar 4, 2015

condition and the other plate has a coating monolayer of azo dye molecules, such that the change ... more condition and the other plate has a coating monolayer of azo dye molecules, such that the change of the orientation of azo dye isomers, due to light, causes changes in the nematic director. We find an approximated expression for the density of isomers, written in terms of the director angle, which allows us to close the equation for the director's angle on the boundary having a photosensitive plate. We have managed to decouple the director's angle and the isomer densities by assuming extremely different temporal time scales between them. We show that switching times inversely depend on trans-cis transition rate of photo-excitation meanwhile relaxation times do not depend on it, for a given sample. On the other hand, switching and relaxation times linearly depend on surface viscosity values.

Inter Press Service English News Wire, Apr 4, 2005

Inter Press Service English News Wire, Mar 28, 2005

The Journal of Prosthetic Dentistry, 2016

The objectives for restoring endodontically treated teeth are to maintain their structural integr... more The objectives for restoring endodontically treated teeth are to maintain their structural integrity and retain them as fully functional units in the dentition. 1 During endodontic instrumentation, root canals are cleaned and shaped in a manner that respects their morphology without altering or weakening their roots. 2 Endodontically treated teeth often require the placement of a post and core for crown restoration. 3 Fractures of endodontically treated teeth have been attributed to weakened tooth structure caused by endodontic and restorative procedures. 4 Occlusal stresses and reduced mechanical properties of endodontically treated teeth may also contribute to fatigue-induced root fractures. 5 An investigation using 3-dimensional finite analysis found that the amount of remaining coronal dentin and the type of post and crown used to restore endodontically treated teeth had a significant effect on stress distribution and fracture resistance. 6 Removal of excessive dentin during root canal instrumentation and preparation for dowels and posts can result in the loss of root strength and an Supported by a research grant from the American Association of Endodontists Foundation.

Revista Mexicana de Fisica

Not Available Bibtex entry for this abstract Preferred format for this abstract (see Preferences)... more Not Available Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints

Optik - International Journal for Light and Electron Optics, 2015

Abstract We consider a planar dielectric waveguide with a very sharp thin slab of distinct refrac... more Abstract We consider a planar dielectric waveguide with a very sharp thin slab of distinct refractive index immersed on it. We obtain the band structure of this integrated waveguide as function of the contrast index, and show that there are propagating modes whose transverse distribution of their amplitudes is both oscillating and exponentially decaying. The oscillating modes exhibit the usual dispersion relation of a standard waveguide, while the evanescent modes give place to a different dispersion relation which does not have cut-off frequency and whose group velocity is superluminal. Thus, this guide allows us for a sub-wavelength propagation regime, as observed in certain metamaterials waveguides.

The behavior of the reflectance coefficient R as function of the incident angle i is calculated a... more The behavior of the reflectance coefficient R as function of the incident angle i is calculated and measured by using total internal reflection techniques. We model the propagation of a linearly polarized Gaussian beam through a nematic cell with a hybrid configuration in the total internal reflection regime. In the optical limit approximation this model allows us to calculate analytically

Optics Communications, 2015

ABSTRACT We consider a one-dimensional nonlinear photonic crystal consisting of an infinite set o... more ABSTRACT We consider a one-dimensional nonlinear photonic crystal consisting of an infinite set of concentrated equidistant scatterers inserted in a linear dielectric medium. Each of the scatterers is made by a very thin layer of a nonlinear medium with high refractive index that we model by a delta function. We show that the nonlinear optical exact solutions of this system form an intensity dependent band structure. To analyze the stability of these solutions we consider a modulation harmonic perturbation of these solutions whose amplitudes are slightly above the instability threshold. We demonstrate that the nonlinearity gives rise to an oscillatory instability of the solutions, which is a localized version of the well-known modulational instability of the nonlinear Schrodinger equation. We show that the linear harmonic perturbation forms as well a band structure whose allowed bands coincide for some intervals with those of the nonlinear band structure of the solutions for which case the structures are unstable whereas in the region where both the linear and nonlinear bands do not coincide, the nonlinear waves are indeed stable so that they conform spatial solitons.

Physical Review E, 2014

We use a molecular-motor model previously proposed for a nematic cell with an azo-dye monolayer t... more We use a molecular-motor model previously proposed for a nematic cell with an azo-dye monolayer to calculate the director orientation when light is normally impinged on the cell. We consider an initial planar configuration for which one of the surrounding plates, which we call the reference plate, is submitted to a hard-anchoring boundary condition. The other confining plate has a coating monolayer of azo-dye molecules such that the change of the orientation of azo-dye isomers, due to light, causes changes in the nematic director. The boundary conditions on both plates along with the optical field determine the director configuration in the bulk. The existence of periodic solutions for the density of isomers in trans and cis states, corresponding to weak optical fields, has been discussed in the literature. Using a similar approach, we find an approximate expression for the density of isomers, written in terms of the director angle, which allows us to close the equation for the director configuration on the boundary having a photosensitive plate. We decouple the director's angle and the isomer densities by assuming extremely different temporal time scales between them. We show for a given sample that switching times inversely depend on the trans-cis transition rate of photoexcitation whereas relaxation times do not depend on it. On the other hand, switching and relaxation times linearly depend on effective surface viscosity values. Our model allows us to estimate surface viscosity values.

SAGVNTVM. Papeles del Laboratorio de Arqueología de Valencia, 2012

Journal of Bacteriology, 2017

Gram-positive bacteria utilize exported peptides to coordinate genetic and physiological processe... more Gram-positive bacteria utilize exported peptides to coordinate genetic and physiological processes required for biofilm formation, stress responses and ecological competitiveness. One example is activation of natural genetic competence by ComR and the com X - i nducing p eptide (XIP) in Streptococcus mutans . Although the competence pathway can be activated by addition of synthetic XIP in defined medium, the hypothesis that XIP is able to function as an intercellular signal molecule has not been rigorously tested. Co-culture model systems were developed that included a “sender” strain that overexpressed the XIP precursor (ComS) and a “responder” strain harboring a GFP reporter fusion to a ComR-activated gene ( comX ) promoter. The ability of the sender strain to provide a signal to activate GFP expression was monitored at the individual cell and population levels using i) planktonic culture systems, ii) cells suspended in an agarose matrix or iii) cells growing in biofilms. XIP was ...

Bulletin of the American Physical Society, Mar 5, 2015

heat to create a combustion front that raises the fuel temperature, decreasing its viscosity, mak... more heat to create a combustion front that raises the fuel temperature, decreasing its viscosity, making extraction easier. The oil is taken toward the productor by means of a vigorous gas thrust as well as a water thrust. To improve and enhance this technique in the field wells, it has been widely perform experimental laboratory tests, in which an in-situ combustion tube is designed to simulate the extraction process. In the present work we propose to solve analytically the problem, with a parabolic partial differential equation associated to the convection-diffusion phenomenon, equation which describes the in-situ combustion process. The whole mathematical problem is established by completing this equation with the correspong boundary and initial conditions, the thickness of the combustion zone, flow velocity, and more parameters. The theoretically obtained results are compared with those reported in literature. We further, fit the parameter of our model to the mentioned data taken from the literature.

Bulletin of the American Physical Society, Mar 4, 2015

Submitted for the MAR15 Meeting of The American Physical Society Biviscous blood flow and a new m... more Submitted for the MAR15 Meeting of The American Physical Society Biviscous blood flow and a new method for velocity profile adjustment CARLOS VELAZQUEZ, ADRIAN REYES, Universidad Nacional Autonoma de Mexico-In this paper we describe our proposal of a new numerical procedure for the adjusting of the velocity profile of body fluids with two viscosities. We have focused on the relevant case of the human blood and we have selected a particular model, the biviscous blood model, with the purpose of proving the convenience of our method. We start by describing the convenience of the biviscous stress equation as a model for the blood constitutive equation, then we solve it in the particular case of a stationary flow and use this solutions as the basis of our numerical procedure, which is described afterwards. Then, we present its implementation for analyzing in vivo measurements and exhibit its pertinence. Finally, we explain the design of a programmatic code of an automatic routine which is capable of applying our method and therefore could be used as the basis of an automatic implementation in new diagnosis software within a measurement device.

Inter Press Service English News Wire, Mar 29, 2005

Saguntum Papeles Del Laboratorio De Arqueologia De Valencia, 2014

Sagvntvm Papeles Del Laboratorio De Arqueologia De Valencia, Aug 9, 2011

Bulletin of the American Physical Society, Mar 4, 2015

condition and the other plate has a coating monolayer of azo dye molecules, such that the change ... more condition and the other plate has a coating monolayer of azo dye molecules, such that the change of the orientation of azo dye isomers, due to light, causes changes in the nematic director. We find an approximated expression for the density of isomers, written in terms of the director angle, which allows us to close the equation for the director's angle on the boundary having a photosensitive plate. We have managed to decouple the director's angle and the isomer densities by assuming extremely different temporal time scales between them. We show that switching times inversely depend on trans-cis transition rate of photo-excitation meanwhile relaxation times do not depend on it, for a given sample. On the other hand, switching and relaxation times linearly depend on surface viscosity values.

Inter Press Service English News Wire, Apr 4, 2005

Inter Press Service English News Wire, Mar 28, 2005

The Journal of Prosthetic Dentistry, 2016

The objectives for restoring endodontically treated teeth are to maintain their structural integr... more The objectives for restoring endodontically treated teeth are to maintain their structural integrity and retain them as fully functional units in the dentition. 1 During endodontic instrumentation, root canals are cleaned and shaped in a manner that respects their morphology without altering or weakening their roots. 2 Endodontically treated teeth often require the placement of a post and core for crown restoration. 3 Fractures of endodontically treated teeth have been attributed to weakened tooth structure caused by endodontic and restorative procedures. 4 Occlusal stresses and reduced mechanical properties of endodontically treated teeth may also contribute to fatigue-induced root fractures. 5 An investigation using 3-dimensional finite analysis found that the amount of remaining coronal dentin and the type of post and crown used to restore endodontically treated teeth had a significant effect on stress distribution and fracture resistance. 6 Removal of excessive dentin during root canal instrumentation and preparation for dowels and posts can result in the loss of root strength and an Supported by a research grant from the American Association of Endodontists Foundation.

Revista Mexicana de Fisica

Not Available Bibtex entry for this abstract Preferred format for this abstract (see Preferences)... more Not Available Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints

Optik - International Journal for Light and Electron Optics, 2015

Abstract We consider a planar dielectric waveguide with a very sharp thin slab of distinct refrac... more Abstract We consider a planar dielectric waveguide with a very sharp thin slab of distinct refractive index immersed on it. We obtain the band structure of this integrated waveguide as function of the contrast index, and show that there are propagating modes whose transverse distribution of their amplitudes is both oscillating and exponentially decaying. The oscillating modes exhibit the usual dispersion relation of a standard waveguide, while the evanescent modes give place to a different dispersion relation which does not have cut-off frequency and whose group velocity is superluminal. Thus, this guide allows us for a sub-wavelength propagation regime, as observed in certain metamaterials waveguides.

The behavior of the reflectance coefficient R as function of the incident angle i is calculated a... more The behavior of the reflectance coefficient R as function of the incident angle i is calculated and measured by using total internal reflection techniques. We model the propagation of a linearly polarized Gaussian beam through a nematic cell with a hybrid configuration in the total internal reflection regime. In the optical limit approximation this model allows us to calculate analytically

Optics Communications, 2015

ABSTRACT We consider a one-dimensional nonlinear photonic crystal consisting of an infinite set o... more ABSTRACT We consider a one-dimensional nonlinear photonic crystal consisting of an infinite set of concentrated equidistant scatterers inserted in a linear dielectric medium. Each of the scatterers is made by a very thin layer of a nonlinear medium with high refractive index that we model by a delta function. We show that the nonlinear optical exact solutions of this system form an intensity dependent band structure. To analyze the stability of these solutions we consider a modulation harmonic perturbation of these solutions whose amplitudes are slightly above the instability threshold. We demonstrate that the nonlinearity gives rise to an oscillatory instability of the solutions, which is a localized version of the well-known modulational instability of the nonlinear Schrodinger equation. We show that the linear harmonic perturbation forms as well a band structure whose allowed bands coincide for some intervals with those of the nonlinear band structure of the solutions for which case the structures are unstable whereas in the region where both the linear and nonlinear bands do not coincide, the nonlinear waves are indeed stable so that they conform spatial solitons.

Physical Review E, 2014

We use a molecular-motor model previously proposed for a nematic cell with an azo-dye monolayer t... more We use a molecular-motor model previously proposed for a nematic cell with an azo-dye monolayer to calculate the director orientation when light is normally impinged on the cell. We consider an initial planar configuration for which one of the surrounding plates, which we call the reference plate, is submitted to a hard-anchoring boundary condition. The other confining plate has a coating monolayer of azo-dye molecules such that the change of the orientation of azo-dye isomers, due to light, causes changes in the nematic director. The boundary conditions on both plates along with the optical field determine the director configuration in the bulk. The existence of periodic solutions for the density of isomers in trans and cis states, corresponding to weak optical fields, has been discussed in the literature. Using a similar approach, we find an approximate expression for the density of isomers, written in terms of the director angle, which allows us to close the equation for the director configuration on the boundary having a photosensitive plate. We decouple the director's angle and the isomer densities by assuming extremely different temporal time scales between them. We show for a given sample that switching times inversely depend on the trans-cis transition rate of photoexcitation whereas relaxation times do not depend on it. On the other hand, switching and relaxation times linearly depend on effective surface viscosity values. Our model allows us to estimate surface viscosity values.

SAGVNTVM. Papeles del Laboratorio de Arqueología de Valencia, 2012