DANIEL ORTIZ - Academia.edu (original) (raw)

Papers by DANIEL ORTIZ

Research paper thumbnail of Domain Engineering for Enhanced Ferroelectric Properties of Epitaxial (001) BiFeO Thin Films

Research paper thumbnail of Bistua: Revista de la Facultad de Ciencias Básicas

... 2005 María Guerrero / Consuelo Medina / Orlando Martínez / Reggie Barrera / Alberto Aché ESTU... more ... 2005 María Guerrero / Consuelo Medina / Orlando Martínez / Reggie Barrera / Alberto Aché ESTUDIO COMPARATIVO DE LA ECOEPIDEMIOLOGIA DE LA MALARIA EN LAS LOCALIDADES DE LA ISLA DE BETANCOURT DEL MUNICIPIO FERNANDEZ FEO Y BOCA DE ...

Research paper thumbnail of Gas-Phase Collision Induced Dissociation Mechanisms of Peptides. Theoretical and Experimental Study of< i> N</i>-Formylalanylamide Fragmentation

International Journal of Mass Spectrometry, Nov 22, 2012

In order to shed light on the fragmentation mechanisms occurring during the collision induced dis... more In order to shed light on the fragmentation mechanisms occurring during the collision induced dissociation (CID) of peptides in the gas phase, we have studied a model system, the N-formylalanylamide (HCO-Ala-NH 2 ), by coupling experimental and theoretical methods. In particular, we have addressed two different questions arising in such experiments: (i) what is (are) the structure(s) of the ion before collision, and (ii) what are the fragmentation mechanisms occurring after collision with the target gas. For the first question, we coupled the potential energy surface (PES) study done by means of density functional theory (DFT), with Infra Red Multiple Photon Dissociation (IRMPD) spectroscopy. For the second problem, which is actually the main topic of the present work, we coupled quantum mechanics plus molecular mechanics (QM + MM) direct chemical dynamics simulations with tandem mass spectrometry (MS/MS). In addition, in order to better delineate the fragmentation mechanisms and validate those proposed by simulations, isotopic labeling experiments using 2 H and 13 C were performed. Thanks to the interplay between simulations and experiments, it was possible to successfully identify the fragmentation pathways leading to b 1 , y 1 , a 1 and immonium ions. Our mechanisms support the "mobile proton" picture that is supposed to trigger the peptide fragmentation in the gas phase, confirming, from a chemical dynamics point of view, previous theoretical and experimental studies on similar systems.

Research paper thumbnail of Self-Assembly of Archimedean Tilings with Enthalpically and Entropically Patchy Polygons

ACS Nano, 2014

Considerable progress in the synthesis of anisotropic patchy nanoplates (nanoplatelets) promises ... more Considerable progress in the synthesis of anisotropic patchy nanoplates (nanoplatelets) promises a rich variety of highly ordered two-dimensional superlattices. Recent experiments of superlattices assembled from nanoplates confirm the accessibility of exotic phases and motivate the need for a better understanding of the underlying self-assembly mechanisms. Here, we present experimentally accessible, rational design rules for the self-assembly of the Archimedean tilings from polygonal nanoplates. The Archimedean tilings represent a model set of target patterns that (i) contain both simple and complex patterns, (ii) are comprised of simple regular shapes, and (iii) contain patterns with potentially interesting materials properties. Via Monte Carlo simulations, we propose a set of design rules with general applicability to one- and two-component systems of polygons. These design rules, specified by increasing levels of patchiness, correspond to a reduced set of anisotropy dimensions for robust self-assembly of the Archimedean tilings. We show for which tilings entropic patches alone are sufficient for assembly and when short-range enthalpic interactions are required. For the latter, we show how patchy these interactions should be for optimal yield. This study provides a minimal set of guidelines for the design of anisostropic patchy particles that can self-assemble all 11 Archimedean tilings.

Research paper thumbnail of Domain Engineering for Enhanced Ferroelectric Properties of Epitaxial (001) BiFeO Thin Films

Research paper thumbnail of Bistua: Revista de la Facultad de Ciencias Básicas

... 2005 María Guerrero / Consuelo Medina / Orlando Martínez / Reggie Barrera / Alberto Aché ESTU... more ... 2005 María Guerrero / Consuelo Medina / Orlando Martínez / Reggie Barrera / Alberto Aché ESTUDIO COMPARATIVO DE LA ECOEPIDEMIOLOGIA DE LA MALARIA EN LAS LOCALIDADES DE LA ISLA DE BETANCOURT DEL MUNICIPIO FERNANDEZ FEO Y BOCA DE ...

Research paper thumbnail of Gas-Phase Collision Induced Dissociation Mechanisms of Peptides. Theoretical and Experimental Study of< i> N</i>-Formylalanylamide Fragmentation

International Journal of Mass Spectrometry, Nov 22, 2012

In order to shed light on the fragmentation mechanisms occurring during the collision induced dis... more In order to shed light on the fragmentation mechanisms occurring during the collision induced dissociation (CID) of peptides in the gas phase, we have studied a model system, the N-formylalanylamide (HCO-Ala-NH 2 ), by coupling experimental and theoretical methods. In particular, we have addressed two different questions arising in such experiments: (i) what is (are) the structure(s) of the ion before collision, and (ii) what are the fragmentation mechanisms occurring after collision with the target gas. For the first question, we coupled the potential energy surface (PES) study done by means of density functional theory (DFT), with Infra Red Multiple Photon Dissociation (IRMPD) spectroscopy. For the second problem, which is actually the main topic of the present work, we coupled quantum mechanics plus molecular mechanics (QM + MM) direct chemical dynamics simulations with tandem mass spectrometry (MS/MS). In addition, in order to better delineate the fragmentation mechanisms and validate those proposed by simulations, isotopic labeling experiments using 2 H and 13 C were performed. Thanks to the interplay between simulations and experiments, it was possible to successfully identify the fragmentation pathways leading to b 1 , y 1 , a 1 and immonium ions. Our mechanisms support the "mobile proton" picture that is supposed to trigger the peptide fragmentation in the gas phase, confirming, from a chemical dynamics point of view, previous theoretical and experimental studies on similar systems.

Research paper thumbnail of Self-Assembly of Archimedean Tilings with Enthalpically and Entropically Patchy Polygons

ACS Nano, 2014

Considerable progress in the synthesis of anisotropic patchy nanoplates (nanoplatelets) promises ... more Considerable progress in the synthesis of anisotropic patchy nanoplates (nanoplatelets) promises a rich variety of highly ordered two-dimensional superlattices. Recent experiments of superlattices assembled from nanoplates confirm the accessibility of exotic phases and motivate the need for a better understanding of the underlying self-assembly mechanisms. Here, we present experimentally accessible, rational design rules for the self-assembly of the Archimedean tilings from polygonal nanoplates. The Archimedean tilings represent a model set of target patterns that (i) contain both simple and complex patterns, (ii) are comprised of simple regular shapes, and (iii) contain patterns with potentially interesting materials properties. Via Monte Carlo simulations, we propose a set of design rules with general applicability to one- and two-component systems of polygons. These design rules, specified by increasing levels of patchiness, correspond to a reduced set of anisotropy dimensions for robust self-assembly of the Archimedean tilings. We show for which tilings entropic patches alone are sufficient for assembly and when short-range enthalpic interactions are required. For the latter, we show how patchy these interactions should be for optimal yield. This study provides a minimal set of guidelines for the design of anisostropic patchy particles that can self-assemble all 11 Archimedean tilings.