Vibrational Funnels for Energy Transfer in Organic Chromophores.

Photoinduced intramolecular energy transfers in multichromophoric molecules involve nonadiabatic vibronic channels that act as energy transfer funnels. They commonly take place through specific directions of motion dictated by the nonadiabatic coupling vectors. Vibrational funnels may support persistent coherences between electronic states and sometimes delineate the presence of minor alternative energy transfer pathways. The ultimate confirmation of their role on the interchromophoric energy transfer can be achieved by performing nonadiabatic excited-state molecular dynamics simulations by selectively freezing the nuclear motions in question. Our results point out this strategy as a useful tool to identify and evaluate the impact of these vibrational funnels on the energy transfer processes and guide the in silico design of materials with tunable properties and enhanced functionalities. Our work encourages applications of this methodology to different chemical and biochemical processes such as reactive scattering and protein conformational changes, to name a few.

Dynamics of Electronically Excited Metal Atoms (Zn and Cd) in Rare Gas Matrices: Simulation of Multiple-band Emission using Molecular Dynamics with Quantum Transitions.

Molecular dynamics with quantum transitions approach is employed to simulate the spectroscopic characteristics of the 1 P1 ↔1 S0 transitions in atomic zinc and cadmium in order to gain insight into the excited state behavior of these atoms isolated in solid rare gases neon, argon, and krypton. The absorption and emission spectra are simulated. Non-radiative processes play a fundamental role in the transfer of population among the three electronic states initially accessed in absorption. Three distinct relaxation pathways were identified. Two of these are related to the dynamical modes described in previous works [McCaffrey and Kerins, J. Chem. Phys. 106, 7885 (1997); Kerins and McCaffrey, J. Chem. Phys. 109, 3131 (1998)] in which the system evolves to form a square planar configuration around the metal atom. The third distinct pathway involves motion on a hexagonal close packed plane. The temperature dependence of complex formation was also determined for the three relaxation pathways.

The stochastic wave function method for diffusion of alkali atoms on metallic surfaces.

The stochastic wave function method is proposed to study the diffusion regimes of alkali atoms on metallic surfaces. The Lindblad approach, based on the microscopic Hamiltonian information in the Caldeira-Leggett model, is presented and numerical calculations of the dynamics are carried out to characterize surface diffusion for two different systems: Na-Cu(111) and Li-Cu(111). Calculations of the intermediate scattering function for an isolated adsorbate are compared, in the Brownian limit, with results deduced from helium spin-echo (HeSE) experiments after reducing them to single adsorbate dynamics. To illustrate the method we present the dependence on momentum transfer and the temperature dependency. Results show that the experiment can be described at a quantitative level by the 1-D quantum model (reduced dimensionality).

Surface diffusion within the Caldeira-Leggett formalism.

Surface diffusion is described in terms of the intermediate scattering function in the time domain and reciprocal space. Two extreme time regimes are analyzed, ballistic (very short times) and Brownian or diffusive (very long times). This open dynamics is studied from the master equation for the reduced density matrix within the Caldeira-Leggett formalism. Several characteristic magnitudes in this decoherence process such as the coherence length, ensemble width and purity of the density matrix are analyzed. Furthermore, for flat surfaces, the surface diffusion is considered for the Schrödinger cat states and identical adsorbates or adparticles, bosons and fermions. The analytical results are compared with those issued from solving the Lindblad master equation through the stochastic wave function method. This numerical analysis is extended to be applied to corrugated surfaces.

Experiencia inicial de la revascularización coronaria percutánea mediante el acceso transradial en el Instituto de Cardiología y Cirugía Cardiovascular / Initial experience of percutaneous coronary revascularization through transradial access at the Institute of Cardiology and Cardiovascular Surgery

Introducción: En los últimos años la utilización de la vía radial como forma de acceso para la realización de estudios diagnósticos e intervencionista ha cobrado mayor importancia e interés dentro de los servicios de cardiología intervencionista a nivel mundial. Nuestro país no escapa de este auge por la baja tasa de complicación y la mayor comodidad para el paciente. Objetivo: Caracterizar la intervención coronaria percutánea mediante la vía de acceso radial en pacientes atendidos en el Instituto de Cardiología y Cirugía Cardiovascular. Método: Estudio observacional, descriptivo, transversal. Muestra compuesta por 211 pacientes a los que se les realizó intervencionismo coronario percutáneo mediante la vía de acceso radial. Resultados: Predominó el sexo masculino (61,2 por ciento). La edad media fue 60,1 ±9,8 años. El Síndrome Coronario Crónico (76,3 por ciento ) fue el diagnóstico mayoritario, la hipertensión arterial el factor de riesgo más frecuente (73,9 por ciento ) y entre los antecedentes personales la cardiopatía isquémica (30,3 por ciento ). El intervencionismo de forma electiva se realizó en el 76,3 de los casos, utilizando la vía radial derecha en el 88,2 por ciento . Se demostró enfermedad de 2 y 3 vasos en el 45,1 por ciento de los pacientes. El proceder fue exitoso en el 96,7 por ciento de los pacientes. Las variables que demostraron relación estadísticamente significativa con el fracaso fueron: fracción de eyección del ventrículo izquierdo < 40 por ciento (p<0.0001), filtrado glomerular ≤ 60 ml/min (p=0.002), antecedente de cardiopatía isquémica (p= 0.016) y presencia de enfermedad coronaria de 3 vasos (p= 0.019). Conclusiones: La intervención coronaria percutánea mediante el acceso radial en el ICCCV es segura y eficaz, con una tasa de éxito elevada y escasas complicaciones(AU)

Introduction: In recent years the use of the radial approach as a form of access for diagnostic and interventional studies has become increasingly important and of interest in interventional cardiology services worldwide. Our country has not escaped this boom due to the low complication rate and greater patient comfort. Objective: To characterise percutaneous coronary intervention using the radial access route in patients attended at the Institute of Cardiology and Cardiovascular Surgery. Methods: Observational, descriptive, cross-sectional study. The sample consisted of 211 patients who underwent percutaneous coronary intervention via the radial access route. Results: Male sex predominated (61.2 percent). Mean age was 60.1 ±9.8 years. Chronic coronary syndrome (76.3 percent) was the most common diagnosis, hypertension the most frequent risk factor (73.9) percent and ischaemic heart disease (30.3 percent ). Elective intervention was performed in 76.3 percent of cases, using the right radial approach in 88.2 percent . Two- and three-vessel disease was demonstrated in 45.1 percent of patients. The procedure was successful in 96.7 percent of patients. Variables demonstrating statistically significant relationship with failure were: left ventricular ejection fraction < 40 percent (p(0.0001), glomerular filtration rate ≤ 60 ml/min (p=0.002), history of ischaemic heart disease (p= 0.016) and presence of 3-vessel coronary artery disease (p= 0.019). Conclusions: Percutaneous coronary intervention via radial access in ICCCV is safe and effective, with a high success rate and few complications(AU)

Trombosis muy tardía de stent metálico convencional: Un suceso inesperado

RESUMEN La trombosis muy tardía de stent es un fenómeno de baja frecuencia, pero de elevada morbilidad y mortalidad. Dentro de sus factores predisponentes se encuentran parámetros clínicos, anatómicos y relacionados con el procedimiento. Múltiples son los mecanismos fisiopatológicos que se plantean como responsables de la trombosis de stent. El tratamiento de esta complicación consiste en intentar restaurar el flujo del vaso lo antes posible. Se presenta el caso de un paciente con el diagnóstico de infarto agudo de miocardio con elevación del segmento ST secundario a trombosis muy tardía de stent metálico convencional (20 meses), tratado exitosamente mediante intervencionismo coronario percutáneo con dos stents liberadores de sirolimus.

ABSTRACT Very late stent thrombosis is a rare complication but with high morbidity and mortality. Predisposing factors include clinical, anatomical and procedure-related parameters. Many pathophysiological mechanisms are considered to be responsible for stent thrombosis. The treatment of this complication consists of attempting to restore blood flow as soon as possible. We present the case of an individual diagnosed with ST-segment elevation myocardial infarction after very late thrombosis of conventional bare metal stent (20 months). The patient was successfully treated by percutaneous coronary intervention with two sirolimus-eluting stents.

Photoinduced Dynamics with Constrained Vibrational Motion: FrozeNM Algorithm.

Ab initio molecular dynamics (AIMD) simulation, analyzed in terms of vibrational normal modes, is a widely used technique that facilitates understanding of complex structural motions and coupling between electronic and nuclear degrees of freedom. Usually, only a subset of vibrations is directly involved in the process of interest. The impact of these vibrations can be evaluated by performing AIMD simulations by selectively freezing certain motions. Herein, we present frozen normal mode (FrozeNM), a new algorithm to apply normal-mode constraints in AIMD simulations, as implemented in the nonadiabatic excited state molecular dynamics code. We further illustrate its capacity by analyzing the impact of normal-mode constraints on the photoinduced energy transfer between polyphenylene ethynylene dendrimer building blocks. Our results show that the electronic relaxation can be significantly slowed down by freezing a well-selected small subset of active normal modes characterized by their contributions in the direction of energy transfer. The application of these constraints reduces the nonadiabatic coupling between electronic excited states during the entire dynamical simulations. Furthermore, we validate reduced dimensionality models by freezing all the vibrations, except a few active modes. Altogether, we consider FrozeNM as a useful tool that can be broadly used to underpin the role of vibrational motion in a studied process and to formulate reduced models that describe essential physical phenomena.

Consideraciones para pacientes con enfermedades cardiovasculares durante la pandemia de la COVID-19 / Considerations for patients with cardiovascular diseases during the COVID-19 pandemic

La enfermedad infecciosa causada por el nuevo coronavirus-2019 (COVID-19), produce un síndrome respiratorio agudo con implicaciones significativas en el sistema cardiovascular tanto en los pacientes con enfermedad cardiovascular preexistente (ECV), que poseen un riesgo de empeoramiento de su enfermedad y muerte, como en los que la infección se ha asociado con múltiples complicaciones directas e indirectas cardiovasculares. Las complicaciones cardiovasculares asociadas con más frecuencia a esta entidad incluyen lesión aguda del miocardio, miocarditis, síndromes coronarios agudos, arritmias y tromboembolismo venoso. Por otra parte, las terapias empleadas para el tratamiento de la enfermedad por COVID-19 pueden tener interacciones medicamentosas con los fármacos cardiovasculares ensombreciendo el pronóstico de los pacientes. El artículo resalta las distintas recomendaciones expuestas por expertos en la literatura médica respecto a las complicaciones cardiovasculares relacionadas con el nuevo coronavirus (COVID-19)(AU)

The infectious disease caused by the new coronavirus-2019 (COVID-19), produces an acute respiratory syndrome with significant implications for the cardiovascular system both in patients with pre-existing cardiovascular disease (CVD), who have a risk of worsening their disease and death, such as those in which the infection has been associated with multiple direct and indirect cardiovascular complications. The cardiovascular complications most frequently associated with this entity include acute myocardial injury, myocarditis, acute coronary syndromes, arrhythmias, and venous thromboembolism. Furthermore, the therapies used to treat COVID-19 disease may have drug interactions with cardiovascular drugs, darkening the prognosis of the patients. The present work attempts to highlight the different recommendations made by experts in the medical literature regarding cardiovascular complications related to the new coronavirus (COVID-19)(AU)

Initial experience of cardiac catheterization through distal radial access in a femoralist center / Experiencia inicial de cateterización cardiaca mediante acceso radial distal en un centro femoralista

Objective: to share our experience in the radial distal approach to perform coronary angiography and / or dilation of coronary stenosis. The initial results are exposed in the access of the distal radial artery or in the so-called anatomical "snuff box". Methods: The left or right radial distal artery was used as an access site in 6 patients admitted to the Institute of Cardiology and Cardiovascular Surgery for coronary angiography and dilatation of coronary stenosis between May 6 and June 6 of 2019. All with pulse present in their distal radial artery. In the laboratory, they had the access arm flexed with respect to the homolateral shoulder so that the hand was placed on their contralateral groin. In all cases, the operator was placed on the right side of the patient, to perform coronary angiography and / or dilation of coronary stenosis. During the hospital stay, the main demographic characteristics and complications were recorded. Results: the average age of the patients was 72 +/- 10 years and 83.3 percent were men. We use the Judkins and Amplatz 6 and 5 French catheters for the procedures. Five admitted with the diagnosis of angina and one with severe aortic valve stenosis. In 5 patients, distal transradial coronary angiography was successfully performed. Only one patient experienced distal radial spasm, using in this case the ipsilateral proximal radial access, without making it necessary to approach the femoral artery. In total, 4 patients had coronary intervention, performing successfully in the 4 patients. The right coronary artery was the artery that required most of the intervention (3 patients). There were no cases of occlusion of the radial arteries, no hematoma of the hand, of the B.A.R.C scale greater than 1 was observed in any patient. Numbness of the hand was documented in none. The radial introducer was removed at the end of the procedure. Hemostasis was achieved with manual compression. Conclusion: the distal radial approach is feasible in a selected group of patients as a procedure for coronary angiography and dilatation of coronary stenosis(AU)

Objetivo: compartir nuestra experiencia en el abordaje radial distal para realizar la angiografía coronaria y/o la dilatación de la estenosis coronaria. Se exponen los resultados iniciales en el acceso de la arteria radial distal o en la llamada "tabaquera" anatómica. Métodos: se utilizó la arteria radial distal izquierda o derecha como sitio de acceso en 6 pacientes ingresados en el Instituto de Cardiología y Cirugía Cardiovascular para angiografía coronaria y dilatación de estenosis coronaria del 6 de mayo al 6 de junio de 2019. Todos los pacientes tenían pulso en la arteria radial distal. En el laboratorio, se les flexionó el brazo de acceso con respecto al hombro homolateral de modo que la mano descansara sobre la ingle contralateral. En todos los casos, el técnico se situó a la derecha del paciente para realizar la angiografía coronaria y/o dilatación de la estenosis coronaria. Durante la estancia de los pacientes en el hospital, se registraron sus principales características demográficas y complicaciones. Resultados: la edad promedio de los pacientes fue de 72 +/- 10 años y 83,3 por ciento eran hombres. Usamos catéteres franceses Judkins y Amplatz 6 y 5 para los procedimientos. Cinco pacientes habían sido ingresados con un diagnóstico de angina y uno con estenosis valvular aórtica severa. La angiografía coronaria transradial distal fue exitosa en 5 pacientes. Solo un paciente experimentó un espasmo distal radial, usándose en ese caso el acceso radial proximal ipsilateral sin que fuera necesario abordar la arteria femoral. Un total de 4 pacientes se sometieron a intervención coronaria, la que fue exitosa en los 4. La arteria coronaria derecha fue la que requirió la mayor parte de la intervención (3 pacientes). No hubo ningún caso de oclusión de las arterias radiales ni de hematoma de la mano. Tampoco se observó un valor de la escala BARC mayor de 1 en ningún paciente. No se documentó entumecimiento de la mano en ningún paciente. El introductor radial se retiró al final del procedimiento. La hemostasia se alcanzó mediante compresión manual. Conclusión: el abordaje radial distal es factible en un grupo seleccionado de pacientes como procedimiento para la angiografía coronaria y la dilatación de la estenosis coronaria(AU)

2-Chloromalonaldehyde, a model system of resonance-assisted hydrogen bonding: vibrational investigation.

The chelated enol isomer of 2-chloromalonaldehyde (2-ClMA) is experimentally characterized for the first time by IR and Raman spectroscopies. The spectra are obtained by trapping the molecule in cryogenic matrices and analyzed with the assistance of theoretical calculations. Experiments were performed in argon, neon and para-hydrogen matrices. The results highlight puzzling matrix effects, beyond site effects, which are interpreted as due to a tunneling splitting of the vibrational levels related to the proton transfer along the internal hydrogen bond (IHB). 2-ClMA is thus one of the very few molecules in which the H tunneling has been observed in cryogenic matrices. The comparison with its parent molecule (malonaldehyde) shows experimentally and theoretically the weakening of the IHB upon chlorination, with a reduced cooperative effect in the resonance assisted hydrogen bond. In addition, the Cl substitution induces an important stabilization of two open enol conformers. These two open forms appear in the spectra of as-deposited samples, meaning that, in contrast with other well-studied molecules of the same family (ß-dialdehydes and ß-diketones), they are present in the gas phase at room temperature.

Hg-Xe exciplex formation in mixed Xe/Ar matrices: molecular dynamics and luminescence study.

Luminescence of Hg((3)P1) atoms trapped in mixed Ar/Xe matrices containing a small amount of Xe is reported. Broad emission bands, strongly red-shifted from absorption are recorded which are assigned to strong complexes formed between the excited mercury Hg* and xenon atoms. Molecular dynamics calculations are performed on simulated Xe/Ar samples doped with Hg to follow the behavior of Hg* in the mixed rare gas matrices leading to exciplex formation. The role of Xe atoms in the first solvation shell (SS1) around Hg was investigated in detail, revealing the formation of two kinds of triatomic exciplexes; namely, Xe-Hg*-Xe and Ar-Hg*-Xe. The first species exists only when two xenon atoms are present in SS1 with specific geometries allowing the formation of a linear or quasi-linear exciplex. In the other geometries, or in the presence of only one Xe in SS1, a linear Ar-Hg*-Xe exciplex is formed. The two kinds of exciplexes have different emission bands, the most red-shifted being that involving two Xe atoms, whose emission is very close to that observed in pure Xe matrices. Simulations give a direct access to the analysis of the experimental absorption, emission, and excitation spectra, together with the dynamics of exciplexes formation.

A langevin canonical approach to the dynamics of chiral systems: thermal averages and heat capacity.

A Langevin canonical framework for a chiral two-level system coupled to a bath of harmonic oscillators was developed within a coupling scheme different from the well-known spin-boson model. Thermal equilibrium values were reached at asymptotic times by solving the corresponding set of nonlinear coupled equations in a Markovian regime. In particular, phase difference thermal values (or, equivalently, the so-called coherence factor) and heat capacity through energy fluctuations were obtained and are discussed in terms of tunneling rates and asymmetries.