Theoretical Research on the Photophysics and Photochemistry of Water Aggregates and DNA/RNA Nucleobases

La presente Tesis Doctoral provee una serie de conclusiones basadas en los estudios realizados durante la realización de la misma. En líneas generales, la caracterización teórica de las propiedades espectroscópicas asociadas al agua ha sido completada y ampliada. Diferentes modelos de agua han sido postulados para mejorar la cararcterización tanto del agua tipo “bulk”, generalmente asignada a la parte interior del agua líquida en la que hay un equilibrio dinámico de los enlaces de hidrógeno, así como del agua denominada estructurada u ordenada, presente generalmente en la interfase entre sólidos y biomoléculas y la propia agua líquida. Ambos tipos de agua poseen señales espectroscópicas diferenciables, caracterizadas claramente desde un punto de vista experimental, facilitando datos experimentales con los que comparar los valores teóricos aquí postulados para proveer de un mecanismo molecular que explique las diferentes señales medidas en ambas. Los estados excitados del agua que han sido investigados son aquellos involucrados en procesos originados por la irradiación con luz UV y por la ionización, facilitando su comprensión e impulsando el conocimiento en áreas relacionadas como lo son el daño en el ADN/ARN, de vital importancia para la investigación biomédica. En contreto, la adición de electrones disociativa en nucleobases (“dissociative electron attachment”) debida a los electrones sueltos tras la ionización del agua y su posterior fijación en nucleobases, es precursora de roturas de las cadenas de ADN/ARN. La línea de investigación basada en el estudio de los procesos fotoquímicos en el ADN/ARN ha sido continuada a través del análisis de los mencionados procesos de adición de electrones disociativa en el uracilo. Posteriormente se ha procedido a revisar el conocimiento obtenido durante la última década en el seno del grupo QCEXVAL (“Quantum Chemistry for the Excited State of Valencia”) acerca de los caminos de decaimiento fotoquímicos que describen la fotoestabilidad de las nucleobases, contrastándolos con métodos más precisos disponibles en la actualidad con tal de validar los mecanismos previamente elucidados.Several conclusions can be derived from the results attained in the current Thesis. In general lines, an improved theoretical characterization of the spectroscopical properties of water has been achieved. Both bulk and ordered water models have been tackled, unveiling their minimal units and their intrinsic intermolecular interactions that make them so different spectroscopically. Those minimal units holding the basic interaction characterizing both bulk and ordered water have been enlarged to propose more realistic models that bear most of the features registered experimentally. Excited states derived from ultraviolet and ionizing radiation have been taken on in order to achieve a more complete understanding of the systems at hand, as well as to provide insights into mediated processes such as the dissociative electron attachment in nucleobases due to the loose electrons generated in conditions of oxidative stress, like the ionization processes in the surrounding water present in the biological systems. Further efforts have been addressed into the DNA/RNA front by investigating new photochemically driven processes, like the aforementioned dissociative electron attachment in uracil. A deep revisit into the main photochemical pathways in the DNA/RNA nucleobases has been also undergone, and new avenues of inquiry are currently being pursued towards the validation of the previously characterized decay channels and also towards the elucidation of the combined effect of distinct intermolecular interactions between nucleobases in their relative position in the DNA/RNA chain

A theoretical study of the intramolecular charge transfer in 4-(dimethylamino)benzethyne

We have investigated the non-adiabatic relaxation processes occurring in the singlet manifold of 4-(dimethylamino)benzethyne (DMABE), a molecule isoelectronic with 4-(dimethylamino)benzonitrile (DMABN) but lacking its characteristic dual fluorescence, using multireference perturbation theory methods. The results obtained point out to the existence of a two-fold decay mechanism in which the population of the initially accessed La state bifurcates towards a locally excited (LE) and a πσ* state. Further relaxation to an emitting intramolecular charge transfer (ICT) state is impeded due to the presence of pronounced energy barriers along their associated potential energy surfaces. These results provide further evidence of the role of πσ* states in the non-adiabatic relaxation processes of dialkylaminobenzonitriles

The highly excited-state manifold of guanine: calibration for nonlinear electronic spectroscopy simulations

A computational protocol based on the complete and restricted active space self-consistent field (CASSCF/RASSCF) methods and their second-order perturbation theory extensions (CASPT2/RASPT2) is employed to benchmark the highly excited-state manifold of the DNA/RNA canonical purine nucleobase guanine in vacuo. Several RASPT2 schemes are tested, displaying a steady convergence of electronic transition energies and dipole moments upon active space enlargement toward the reference values. The outcome allows calibrating and optimizing computational efforts by considering cheaper and more approximate RAS schemes that could enable the characterization of the excited-state manifolds of multi-chromophoric systems, such as DNA/RNA nucleobase dimers or multimers. Simulations of two-dimensional electronic spectra show similar trends to those observed on the other purine nucleobase adenine, deviating from this and other pyrimidine nucleobases in featuring its main excited-state absorption signal, embodied by sizable double HOMO to LUMO excitation contributions, in the UV probing window

Outcome quality standards in advanced ovarian cancer surgery

Advanced ovarian cancer surgery (AOCS) frequently results in serious postoperative complications. Because managing AOCS is difficult, some standards need to be established that allow surgeons to assess the quality of treatment provided and consider what aspects should improve. This study aimed to identify quality indicators (QIs) of clinical relevance and to establish their acceptable quality limits (i.e., standard) in AOCS

Use of orange leaves as a replacement for alfalfa in energy and nitrogen partitioning, methane emissions and milk performance of murciano-granadina goats

[EN] The objective of this experiment was to study the effects of substituting alfalfa with orange leaves on energy, nitrogen and carbon balance, methane emission, and milk performance in dairy goats. Ten Murciano-Granadina dairy goats in mid lactation (43.5 +/- 3.59 kg of body weight [BW]) were selected in a crossover design experiment, where each goat received two treatments in 2 periods. One group of five goats was fed a mixed ration with 450 g of pelleted alfalfa and 550 g of pelleted concentrate/kg of dry matter (ALF diet), and the other diet replaced alfalfa with orange leaves (ORG diet). Inclusion of ORG than ALF diet reduced (P = 0.041) dry matter intake. The metabolizable energy intake was identical between treatments (901 kJ/kg of BW0.75, on average) and, the efficiency of metabolizable energy for milk production was 0.73. Retention of energy was lower (P = 0.001) in ORG diet than ALF diet. Carbon and nitrogen intake (P = 0.022 and P = 0.004, respectively) was greater for diet ALF than ORG, with no differences in milk carbon and nitrogen. The ORG diet reduced (P = 0.037) milk fat 3 g/kg, and CH4 (P = 0.001) 6 g/d. One of the milk fatty acids positively correlated with CH4 production was C16:0; it was greater (P < 0.05) in ALF than ORG diet. When CH4 was expressed over OM digestibility and milk basis, differences were preserved. Results suggest that orange leaves are effective in reducing CH4 emission without detrimental effect on nutrients balance and milk yield.This study was supported by HELIOTEC S.L., La Vall d'Uixo, Castellon de la Plana, Valencia, Spain, though LIFE Ecocitric Project and, LIFE2016/CCM/ES/000088 LOW CARBON FEED.Fernández Martínez, CJ.; Pérez Baena, I.; Martí Vicent, JV.; Palomares Carrasco, JL.; Jorro-Ripoll, J.; Segarra, J. (2019). Use of orange leaves as a replacement for alfalfa in energy and nitrogen partitioning, methane emissions and milk performance of murciano-granadina goats. Animal Feed Science and Technology. 247:103-111. https://doi.org/10.1016/j.anifeedsci.2018.11.008S10311124

Postoperative intestinal fistula in primary advanced ovarian cancer surgery

Background: Advanced ovarian cancer (AOC) requires an aggressive surgery with large visceral resections in order to achieve an optimal or complete cytoreduction and increase the patient’s survival. However, the surgical aggressiveness in the treatment of AOC is not exempt from major complications, such as the gastrointestinal fistula (GIF), which stands out among others due to its high morbidity and mortality. Methods: We evaluated the clinicopathological features in patients with AOC and their association with GI. Data for 107 patients with AOC who underwent primary debulking surgery were analyzed retrospectively. Clinicopathological features, including demographic, surgical procedures and follow-up data, were analyzed in relation to GIF. Results: GIF was present in 11% of patients in the study, 5 (4.5%) and 7 (6.4%) of colorectal and small bowel origin, respectively. GIF was significantly associated with peritoneal cancer index (PCI) > 20, more than 2 visceral resections, and multiple digestive resections. Overall and disease-free survival were also associated with GIF. Multivariate analysis identified partial bowel obstruction and operative bleeding as independent prognostic factors for survival. The presence of GIF is positively associated with poor prognosis in patients with AOC. Conclusion: Given the importance of successful cytoreductive surgery in AOC, the assessment of the amount of tumor and the aggressiveness of the surgery to avoid the occurrence of GIF become a priority in patients with AOC

Adiciones y correcciones a la orquidoflora valenciana, VII

Se aportan datos sobre algunos táxones de Orchidaceae que resultan escasos en la Comunidad Valenciana o en determinadas de sus comarcas; a destacar la presencia de Ophrys santonica y O. × pseudospeculum en Alicante.It is shown some data about rare taxa of Orchidaceae at the Valencian Community (E Spain) or expansions of area to new shires; to emphasize the presence of Ophrys santonica and O. × pseudospeculum in Alicante

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations