Predicting the Electronic Absorption Band Shape of Azobenzene Photoswitches

Simulations based on molecular dynamics coupled to excitation energy calculations were used to generate simulated absorption spectra for a family of halide derivatives of azobenzene, a family of photoswitch molecules with a weak absorption band around 400-600 nm and potential uses in living tissue. This is a case where using the conventional approach in theoretical spectroscopy (estimation of absorption maxima based on the vertical transition from the potential energy minimum on the ground electronic state) does not provide valid results that explain how the observed band shape extends towards the low energy region of the spectrum. The method affords a reasonable description of the main features of the low-energy UV-Vis spectra of these compounds. A bathochromic trend was detected linked to the size of the halide atom. Analysis of the excitation reveals a correlation between the energy of the molecular orbital where excitation starts and the energy of the highest occupied atomic orbital of the free halide atom. This was put to the test with a new brominated compound with good results. The energy level of the highest occupied orbital on the free halide was identified as a key factor that strongly affects the energy gap in the photoswitch. This opens the way for the design of bathochromically shifted variants of the photoswitch with possible applications

On the Computational Design of Azobenzene-Based Multi-State Photoswitches

In order to theoretically design multi-state photoswitches with specific properties, an exhaustive computational study is first carried out for an azobenzene dimer that has been recently synthesized and experimentally studied. This study allows for a full comprehension of the factors that govern the photoactivated isomerization processes of these molecules so to provide a conceptual/computational protocol that can be applied to generic multi-state photoswitches. From this knowledge a new dimer with a similar chemical design is designed and also fully characterized. Our theoretical calculations predict that the new dimer proposed is one step further in the quest for a double photoswitch, where the four metastable isomers could be selectively interconverted through the use of different irradiation sequences

Un modelo de ubicación de microaerogeneradores para el diseño de proyectos de electrificación rural con energía eólica

Postprint (published version

Memory improvement in the AβPP/PS1 mouse model of familial Alzheimer's disease induced by carbamylated-erythropoietin is accompanied by modulation of synaptic genes

Neuroprotection of erythropoietin (EPO) following long-term administration is hampered by the associated undesirable effects on hematopoiesis and body weight. For this reason, we tested carbamylated-EPO (CEPO), which has no effect on erythropoiesis, and compared it with EPO in the AβPP/PS1 mouse model of familial Alzheimer's disease. Groups of 5-month-old wild type (WT) and transgenic mice received chronic treatment consisting of CEPO (2,500 or 5,000 UI/kg) or EPO (2,500 UI/kg) 3 days/week for 4 weeks. Memory at the end of treatment was assessed with the object recognition test. Microarray analysis and quantitative-PCR were used for gene expression studies. No alterations in erythropoiesis were observed in CEPO-treated WT and AβPP/PS1 transgenic mice. EPO and CEPO improved memory in AβPP/PS1 animals. However, only EPO decreased amyloid-β (Aβ) plaque burden and soluble Aβ40. Microarray analysis of gene expression revealed a limited number of common genes modulated by EPO and CEPO. CEPO but not EPO significantly increased gene expression of dopamine receptors 1 and 2, and adenosine receptor 2a, and significantly down-regulated adrenergic receptor α1D and gastrin releasing peptide. CEPO treatment resulted in higher protein levels of dopamine receptors 1 and 2 in WT and AβPP/PS1 animals, whereas the adenosine receptor 2a was reduced in WT animals. The present results suggest that the improved behavior observed in AβPP/PS1 transgenic mice after CEPO treatment may be mediated, at least in part, by the observed modulation of the expression of molecules involved in neurotransmission

An Attentional bias modification task, through virtual reality and eye-tracking technologies, to enhance the treatment of anorexia nervosa

Mirror exposure therapies (METs) have been shown to be effective in reducing body image disturbances through the habituation process. Virtual reality (VR) combined with eye-tracking techniques can provide innovative solutions to some of METs' limitations reported with patients with anorexia nervosa (AN), especially the negative influence of body-related attentional bias (AB). This pilot study aimed to assess the preliminary efficacy of a new VR-based AB modification task (ABMT) among healthy women and the procedure's user experience. AB levels towards weight- and non-weight-related body parts, using complete fixation time (CFT) and number of fixations (NF), were assessed throughout the ABMT procedure (300 trials). The user experience was evaluated at the end of the procedure. The results showed that VR-based ABMT was effective in reducing AB significantly after 150 trials for both CFT- and NF-based measures, although 225 trials were necessary to get the same result for women with an NF initially more oriented towards weight-related body parts. Overall, the software received a 'C-rating' on a scale from 'A' (most usable) to 'F' (least usable). These results provide evidence of the opportunity to use a VR-based ABMT procedure to reduce AB and improve existing treatments for AN

Attentional Bias Modification Training Based on Virtual Reality and Eye Tracking in Anorexia Nervosa Patients

Anorexia nervosa (AN) patients exhibit attentional bias (AB) related to the body, which is the tendency to pay greater attention to weight-related body areas compared to non-weight-related ones. This phenomenon has been linked to elevated levels of body dissatisfaction (BD) and may potentially reduce the effectiveness of body exposure therapy. The purpose of this pilot study is to assess the efficacy of a single session of a new body-related AB modification task (ABMT) that combines virtual reality with eye tracking in patients with AN. The goals of the ABMT are to reduce body-related AB by balancing attention between weight and non-weight-related body areas and to reduce BD levels. Twenty-three adolescent patients with AN were embodied in a virtual avatar and immersed in a virtual environment where they completed the ABMT. Body-related AB measures and BD levels were assessed before and after the training. A paired samples t-test showed statistically significant differences between pre-assessment and post-assessment; the complete fixation time on weight-related body parts was reduced and BD levels decreased. The initial evidence of the efficacy of this ABMT has important clinical implications, since AB and BD are considered risk factors for developing and maintaining eating disorder symptomatology among patients with AN

Modification of Body-Related Attentional Bias through Virtual Reality and Eye-Tracking in Healthy Participants: Implications for Anorexia Nervosa Treatments

Cognitive biases have a significant impact on the etiology and treatment of eating disorders (EDs). These biases, including selective attentional bias (AB) to disliked body parts, may reinforce concerns about body shape, fear of gaining weight and body image disturbances and may contribute to dietary restriction and restraint. Decreasing AB could reduce core symptoms in anorexia nervosa (AN). This study represents a preliminary exploration aiming to assess whether AB towards weightrelated (WR) and non-weight-related (NW) body parts could be reduced through an AB modification task in a virtual reality (VR) environment in healthy participants. A total of 54 female participants, aged 22.98 ± 1.89, were recruited. The task consisted of directing the participants’ attention towards all body parts equally in a VR setting. Eye-tracking (ET) measurements (complete fixation time [CFT] and number of fixations [NF]) were made before and after the task. The results showed a significant reduction of the AB in the two groups with an initial AB towards WR body parts or towards NW body parts. Participants showed a tendency to more balanced (non-biased) attention after the intervention. This study provides evidence of the usefulness of AB modification tasks in a non-clinical sample

Procedimiento para la evaluación del recurso y diseño de sistemas microeólicos

Los sistemas de electrificación basados en el aprovechamiento de fuentes de energía renovables han demostrado ser adecuados para proveer de electricidad a comunidades aisladas de forma autónoma. En concreto, la electrificación mediante energía eólica es una de las opciones tecnológicas utilizadas recientemente en proyectos implementados en la sierra andina de Perú. Hasta ahora, estos proyectos se han diseñado bajo el concepto de instalaciones individuales en cada punto de consumo. Como alternativa, se propone un diseño que considera la combinación de equipos individuales aislados con la generación y distribución de electricidad mediante una o varias microrredes. La localización de los diferentes tipos de aerogeneradores y el diseño de la(s) microrred(es) se decide considerando el recurso eólico de cada punto y la localización y la demanda de los puntos de consumo. Esta alternativa de diseño incorpora la opción de utilizar equipos de generación de más potencia, proporcionalmente más baratos, y evita condicionar el consumo de una familia al recurso eólico disponible en su domicilio. En este trabajo se presenta un proceso de evaluación de recurso eólico y un modelo matemático de programación lineal entera y mixta para el diseño de sistemas eólicos. El proceso de evaluación de recurso y los resultados del modelo del modelo se validan mediante la aplicación a un caso real implementado en la sierra norte de Perú. Los resultados obtenidos reducen los costes de inversión inicial y utilizan pequeñas microrredes, a pesar de la dispersión de la comunidad y la distancia entre viviendas.Peer ReviewedPostprint (author’s final draft

Electrificación rural con sistemas microeólicos: optimización del diseño

Los sistemas de electrificación basados en el aprovechamiento de fuentes de energía renovables han demostrado ser adecuados para proveer de electricidad a comunidades aisladas de forma autónoma. En concreto, la electrificación mediante energía eólica es una de las opciones tecnológicas utilizadas recientemente en proyectos implementados en la sierra andina de Perú. Hasta ahora, estos proyectos se han diseñado bajo el concepto de instalaciones individuales en cada punto de consumo. Como alternativa, se propone un diseño que considera la combinación de equipos individuales aislados con la generación y distribución de electricidad mediante una o varias microrredes. La localización de los diferentes tipos de aerogeneradores y el diseño de la(s) microrred(es) se decide considerando el recurso eólico de cada punto y la localización y la demanda de los puntos de consumo. Esta alternativa de diseño incorpora la opción de utilizar equipos de generación de más potencia, proporcionalmente más baratos, y evita condicionar el consumo de una familia al recurso eólico disponible en su domicilio. En este trabajo se presenta un proceso de evaluación de recurso eólico y un modelo matemático de programación lineal entera y mixta para el diseño de sistemas eólicos. El proceso de evaluación de recurso y los resultados del modelo del modelo se validan mediante la aplicación a un caso real implementado en la sierra norte de Perú. Los resultados obtenidos reducen los costes de inversión inicial y utilizan pequeñas microrredes, a pesar de la dispersión de la comunidad y la distancia entre viviendas.Postprint (published version

Avaluació de recurs o disseny de sistemes micro-eòlics per a la electrificació rural

Els sistemes d’electrificació basats en l’aprofitament de fonts d’energia renovables disponibles localment, han demostrat ser adequats per a proveir d’electricitat a comunitats aïllades de forma autònoma, i contribuir així a la sostenibilitat de les formes de vida rurals en països en desenvolupament. En concret, l’electrificació mitjançant energia eòlica és una de les opcions tecnològiques emprades recentment en projectes implementats en la serra andina de Perú. Fins ara, aquests projectes s’han dissenyat sota el concepte d’instal·lació d’un micro-aerogenerador individual per a cada punt de consum, especialment per a comunitats amb una dispersió moderada. Tot i haver demostrar la seva idoneïtat, aquest tipus de disseny és millorable des del punt de vista d’augment de la sostenibilitat econòmica, social i ambiental dels projectes d’electrificació amb energia micro-eòlica. Com a alternativa, es proposa un nou concepte de disseny per a comunitats disperses que considera la combinació d’equips individuals aïllats amb la generació i distribució d’electricitat mitjançant una o diverses micro-xarxes de distribució elèctrica. La localització dels diferents tipus d’aerogeneradors i el disseny de la micro-xarxa es decideixen considerant el recurs eòlic de cada punt i la localització i la demanda dels punts de consum. Aquesta alternativa de disseny incorpora l’opció d’utilitzar equips de generació més grans, proporcionalment més barats i de menor impacte ambiental, i evita condicionar el consum d’una família al recurs eòlic disponible a casa seva, augmentant l'impacte i el benefici econòmic i social sobre les persones beneficiaries, al temps que disminueix els requeriments i les despeses de manteniment. En aquest treball es presenta un procés d’avaluació de recurs eòlic i un model matemàtic de programació lineal entera i mixta per al disseny de sistemes eólics amb possiblesmicro-xarxes. El procés d’avaluació de recurs i els resultats del model del model es validen mitjançant l’aplicació a un cas real implementat en la serra nord de Perú. Els resultats obtinguts redueixen els costos d’inversió inicial i utilitzen petites micro-xarxes, tot i la dispersió de la comunitat i la distància entre vivendes.Peer ReviewedPostprint (published version