How Do Methyl Groups Enhance the Triplet Chemiexcitation Yield of Dioxetane?

Chemiluminescence is the emission of light as a result of a nonadiabatic chemical reaction. The present work is concerned with understanding the yield of chemiluminescence, in particular how it dramatically increases upon methylation of 1,2-dioxetane. Both ground-state and nonadiabatic dynamics (including singlet excited states) of the decomposition reaction of various methyl-substituted dioxetanes have been simulated. Methyl-substitution leads to a significant increase in the dissociation time scale. The rotation around the O-C-C-O dihedral angle is slowed; thus, the molecular system stays longer in the "entropic trap" region. A simple kinetic model is proposed to explain how this leads to a higher chemiluminescence yield. These results have important implications for the design of efficient chemiluminescent systems in medical, environmental, and industrial applications

Relationship Between The Excited State Relaxation Paths Of Rhodopsin And Isorhodopsin

The pigment Isorhodopsin, an analogue of the visual pigment Rhodopsin, is investigated via quantum-mechanics/molecular-mechanics computations based on an ab initio multiconfigurational quantum chemical, treatment. The limited \u3c5 kcal mol(-1) error found for the spectral parameters allows for a nearly quantitative analysis of the excited-state structure and reactivity of its 9-cis-retinal chromophore. We demonstrate that, similar to Rhodopsin, Isorhodopsin features a shallow photoisomerization path. However, the structure of the reaction coordinate appears to be reversed. In fact, while the coordinate still corresponds to an asynchronous crankshaft motion, the dominant isomerization component involves a counterclockwise, rather than clockwise, twisting of the 9-cis bond. Similarly, the minor component involves a clockwise, rather than counterclockwise, twisting of the 11-trans bond. Ultimately, these results indicate that Rhodopsin and Isorhodopsin relax along a common excited-state potential energy valley starting from opposite ends. The fact that the central and lowest energy region of such valley runs along a segment of the intersection space between the ground and excited states of the protein explains why the pigments decay at distinctive conical intersection structures

The Ultrafast Photoisomerizations Of Rhodopsin And Bathorhodopsin Are Modulated By Bond Length Alternation And Hoop Driven Electronic Effects

Rhodopsin (Rh) and bathorhodopsin (bathoRh) quantum-mechanics/molecular-mechanics models based on ab initio multiconfigurational wave functions are employed to look at the light induced pi-bond breaking and reconstitution occurring during the Rh -\u3e bathoRh and bathoRh -\u3e Rh isomerizations. More specifically, semiclassical trajectory computations are used to compare the excited (S-1) and ground (S-0) state dynamics characterizing the opposite steps of the Rh/bathoRh photochromic cycle during the first 200 fs following photoexcitation. We show that the information contained in these data provide an unprecedented insight into the sub-picosecond pi-bond reconstitution process which is at the basis of the reactivity of the protein embedded 11-cis and all-trans retinal chromophores. More specifically, the data point to the phase and amplitude of the skeletal bond length alternation stretching mode as the key factor switching the chromophore to a bonding state. It is also confirmed/found that the phase and amplitude of the hydrogen-out-of-plane mode controls the stereochemical outcome of the forward and reverse photoisomerizations

Calidad de vida relacionada con la salud de los pacientes con insuficiencia cardiaca crónica sistólica en España: resultados del estudio VIDA-IC

[Resumen] Introducción y objetivos. La calidad de vida relacionada con la salud de los pacientes con insuficiencia cardiaca está afectada. Hay poca información sobre los factores clínicos asociados a esta mala calidad de vida de la población española con insuficiencia cardiaca. Métodos. Estudio multicéntrico transversal de calidad de vida relacionada con la salud aplicando un cuestionario específico (Kansas City Cardiomyopathy Questionnaire) y otro genérico (EuroQol-5D) a 1.037 pacientes ambulatorios consecutivos con insuficiencia cardiaca sistólica. Resultados. Los pacientes con peor calidad de vida presentaron en su mayoría datos asociados a peor pronóstico y mayor gravedad de la enfermedad. Los pacientes del estudio presentaron mayor incidencia de limitaciones en movilidad, dolor/malestar y ansiedad/depresión cuando se realizó una comparación externa con población general y con pacientes con otras afecciones crónicas. La correlación entre las puntuaciones totales de ambos cuestionarios fue muy alta (r de Pearson = 0,815; p < 0,001). Con regresión lineal multivariable, se observó que mayor edad (β estandarizada = –0,2; p = 0,03), sexo femenino (β estandarizada = –10,3; p < 0,001), peor clase funcional (β estandarizada = –20,4; p < 0,001), mayor comorbilidad según índice de Charlson (β estandarizada = –1,2; p = 0,005) y el ingreso reciente por insuficiencia cardiaca (β estandarizada = 6,28; p = 0,006) son factores independientes predictores de peor calidad de vida relacionada con la salud. Conclusiones. Los pacientes con insuficiencia cardiaca tienen muy afectada su calidad de vida respecto a la población general española y a otras enfermedades crónicas. Sexo femenino, edad avanzada, comorbilidad, síntomas avanzados y hospitalización reciente son factores determinantes en la calidad de vida relacionada con la salud de estos pacientes

Photoinduced Proton Transfer as a Possible Mechanism for Highly Efficient Excited-State Deactivation in Proteins

CASSCF//CASPT2 pathways for a two-glycine minimal model system show that photoinduced electron-driven forward and backward proton transfer could play an important role for the stability of proteins against damage by UV radiation, when a hydrogen bond is located between the two amino acids. The overall photoinduced process involves two electron and proton transfer processes (forward and backward) and results in the reformation of the initial closed-shell electronic structure of the system.Ministerio de Educación y CienciaUniversidad de Alcal

Carbon dioxide activation assisted by a bis(chlorodimethylsilyl)cyclopentadienyl titanium compound

A great deal of interest has focused on the role of metal ions\ud as the active centers in the fixation of CO2 and its transformation. Activation of CO2 by hydroxo and oxo metal complexes to afford metal hydrogencarbonato and carbonato\ud species, respectively, is related to the function of the carbonic\ud anhydrase metalloenzyme, which catalyzes the physiologically\ud important hydration of CO2 to hydrogencarbonate

Predictors of optimal pharmacological treatment in patients with heart failure and depressed ejection fraction. Results of the VIDA-IC study

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Diferencias cinemáticas entre saltadores de altura nacionales y saltadores de altura internacionales

The purpose of this study was to establish reference values for various kinematic variables in high jump that allow us to determine an execution model of Spanish athletes and compare it with the technical model proposed in the bibliography. The best jump of the first 25 finalists in the 2009 Spanish indoor championship were analyzed (13 males: height = 1.89 ± 0.05 m, and jump performance = 2.10 ± 0.09 m; and 12 females: height = 1.69 ± 0.10 m, and jump performance = 1.73 ± 0.08 m). A total of 35 kinematic variables related to the run-up (last two steps of the approach run), takeoff, and bar clearance phases were analyzed. A photogrammetric 3D protocol (using three video cameras at 50 frames per second and a Direct Linear Transformation) was used to establish the athletes’ coordinates. The analysis and digitalization of the jumps were done using the Kwon 3D software. The results of the study show that the largest differences between Spanish high jumpers and the model found in the bibliography are found in the pre-jump phase (length, frequency, and speed of steps) and in the take-off phase with regard to the speed of the center of massEl objetivo del trabajo fue fijar valores de referencia en diferentes variables cinemáticas para la prueba de salto de altura que permitan establecer el modelo de ejecución de los atletas nacionales y compararlo con el modelo técnico que establece la bibliografía. Se analizó el mejor intento de 25 saltadores de altura finalistas en el Campeonato de España en pista cubierta 2009 (13 hombres, 1.89 ± 0.05 m de estatura y 2.10 ± 0.09 m de rendimiento, y 12 mujeres, 1.69 ± 0.10 m de estatura y 1.73 ± 0.08 m de rendimiento). Se calcularon un total de 35 variables biomecánicas correspondientes a las fases de ante-salto (dos últimos pasos de la carrera de aproximación), batida y paso del listón. Se utilizó fotogrametría 3D a través de tres cámaras de vídeo operando a 50 fotogramas por segundo y utilizando el algoritmo de Transformación Linear Directa para la determinación de las coordenadas del deportista. El análisis y digitalización de los saltos se realizó en el programa Kwon 3D. Los resultados de este estudio muestran que las mayores diferencias entre los valores en los saltadores y saltadoras españolas al compararlos con los saltadores de nivel internacional se producen durante la fase ante-salto (longitud, frecuencia, y velocidad del paso) y durante la fase de batida a nivel de velocidad del CMActividad Física y Deport

Chiral Hydrogen Bond Environment Providing Unidirectional Rotation in Photoactive Molecular Motors

Generation of a chiral hydrogen bond environment in efficient molecular photoswitches is proposed as a novel strategy for the design of photoactive molecular motors. Here, the following strategy is used to design a retinal-based motor presenting singular properties: (i) a single excitation wavelength is needed to complete the unidirectional rotation process (360°); (ii) the absence of any thermal step permits the process to take place at low temperatures; and (iii) the ultrafast process permits high rotational frequencies.Ministerio de Economía y CompetitividadMinisterio de Ciencia e InnovaciónUniversidad de Alcal

Low-intensity continuous ultrasound to inhibit cancer cell migration

In recent years, it has been verified that collective cell migration is a fundamental step in tumor spreading and metastatic processes. In this paper, we demonstrate for the first time how low-intensity ultrasound produces long-term inhibition of collective migration of epithelial cancer cells in wound healing processes. In particular, we show how pancreatic tumor cells, PANC-1, grown as monolayers in vitro respond to these waves at frequencies close to 1 MHz and low intensities (< 100 mW cm(-2)) for 48-72 h of culture after some minutes of a single ultrasound irradiation. This new strategy opens a new line of action to block the spread of malignant cells in cancer processes. Despite relevant spatial variations of the acoustic pressure amplitude induced in the assay, the cells behave as a whole, showing a collective dynamic response to acoustic performance. Experiments carried out with samples without previous starving showed remarkable effects of the LICUs from the first hours of culture, more prominent than those with experiments with monolayers subjected to fasting prior to the experiments. This new strategy to control cell migration demonstrating the effectiveness of LICUS on not starved cells opens a new line of action to study effects of in vivo ultrasonic actuation on tumor tissues with malignant cells. This is a proof-of-concept study to demonstrate the physical effects of ultrasound stimulation on tumor cell migration. An in-depth biological study of the effects of ultrasounds and underlying biological mechanisms is on-going but out of the scope of this article.This work is financed by the Spanish National Plan projects PID 2021-128985OB-I00: "New Non-invasive technology to inhibit growth of solid tumors by low intensity ultrasounds", DPI 2017-90147-R and intramural research project IRYCIS (2018/0240)