RESUMEN

The computationally-aided photophysical and lasing properties of a selected battery of BOPHYs are described and compared to those of related BODIPY counterparts. The present joined theoretical-experimental study helps to put into context the weaknesses and strengths of both dye families under different irradiation conditions. The chemical versatility of the BOPHY scaffold has been also comparatively explored to modulate key photonic properties towards the development of red-emitting dyes, chiroptical dyes and singlet oxygen photosensitizers. Thus, BOPHY BINOLation by fluorine substitution with enantiopure BINOLs endows the BOPHY chromophore with chiroptical activity, as supporting by the simulated circular dichroism, decreasing deeply its fluorescent response due to the promotion of fluorescence-quenching intramolecular charge transfer (ICT). Interestingly, the sole alkylation of the BOPHY core strongly modulates the promotion of ICT, allowing the generation of highly bright BINOL-based BOPHY dyes. Moreover, 3,3'-dibromoBINOLating BOPHYs can easily achieve singlet-oxygen photogeneration, owing to spin-orbit coupling mediated by heavy-atom effect feasible in view of the theoretically predicted disposition of the bromines surrounding the chromophore. From this background, we have established the master guidelines to design bright fluorophores and laser dyes, photosensitizers for singlet oxygen production and chiroptical dyes based on BOPHYs. The possibility to finely mix and balance such properties in a given molecular scaffold outstands BOPHYs as promising dyes competing with the well-settled BODIPY dyes.

RESUMEN

Laser emission from leaky waveguides based in dye-doped organic gain media incorporating Polyhedral Oligomeric Silsesquioxanes (POSS) nanoparticles is reported. The samples consist of thin film gain media deposited onto glass substrate defining a planar asymmetric slab waveguide, which does not incorporate any resonant substructure. The presence of POSS results in additional amplified spontaneous emission (ASE) spectral narrowing, and conditions have been found for which directional multimode laser emission is achieved. The spectral narrowing is ascribed to the photon path enlargement caused by a non-resonant feedback mechanism provided by individual scatterers, which enhances incoherently the magnitude of the amplification process. On the contrary, the appearance of multimode lasing is attributed to coherent random lasing from a many scatterers collective effect.

Asunto(s)

RESUMEN

The cost of lipases and the relatively slower reaction rate remain as the major obstacles for enzymatic production of biodiesel as opposed to the conventional chemical processes. This paper reviews the starting oils usually employed in biodiesel production, the processes for transforming them to biodiesel placing particular emphasis on enzymatic transesterification. The pros and cons of the lipase-based process, the key operational variables and the technological alternatives for attenuating lipase deactivation are also discussed. Finally, suggestions are made for future studies, paying particular attention to the use of whole cell immobilization in the production process, as this methodology may reduce both the cost of the biocatalyst and dependence on lipase manufacturers.

Asunto(s)

RESUMEN

Amplified spontaneous emission from planar waveguides and quasi-waveguides based on Pyrromethene 567-doped poly(methyl methacrylate) thin films deposited onto quartz and glass substrates is investigated. Films with different thickness were prepared and pumped optically at 532 nm with pulses of up to 8 MW/cm(2). Pump thresholds for the onset of ASE emission, optical gains and losses were assessed. Net gain coefficients were estimated by fitting the data provided by variable stripe length measurements with a theoretical expression which takes into account saturation. In this way, net gain coefficients of up to 56 +/- 9 cm(-1) at a pump intensity of 5.3 MW/cm(2) for quasi-waveguides and up to 20.6 +/- 2.7 cm(-1) at a pump intensity of 3.4 MW/cm2 for waveguides, were obtained. Loss coefficients in the waveguides were estimated to be 3.8 +/- 0.4 cm-1 and 6.1 +/- 1.3 cm(-1) for 15 microm and 5 microm thick films, respectively. The results obtained seem to indicate a stronger self-mode-restriction capability in the quasiwaveguides than in conventional total internal-reflection waveguides.

Asunto(s)

Asunto(s)

RESUMEN

INTRODUCTION: The main purpose of this study was to determine if olanzapine (OLZ) can improve the ability to recognize emotional expressions, in the facial, prosodic and contextual modalities in treatment refractory schizophrenics (TRS) and, if this could be related to its effects on depressive symptoms. METHOD: 14 TRS participated in the study. The Calgary Depression Scale and tasks for recognition of facial, prosodic and contextual emotions were applied prior to and 8 weeks after consuming OLZ. The results were compared to a control group (CO). RESULTS: TRS obtained lower scores than the CO on the recognition of facial and prosodic emotions. They also showed less empathy to the happiness film and they expressed incongruous answers on the contextual emotions. The TRS increased the number of correct responses for the prosodic recognition of happiness and they showed a reduction in their depressive symptomatology after OLZ treatment. CONCLUSIONS: OLZ caused a decrease of the depressive symptoms and improved the interpretation of positive prosodic affective stimuli, an aspect that may facilitate the social adaptation of TRS.

Asunto(s)

RESUMEN

Introducción. Algunos de los procesos afectados en la esquizofrenia son la atención y el reconocimiento emocional. El objetivo de este estudio fue probar varias cuestiones: 1. Si en los esquizofrénicos refractarios (RE) existen mayores alteraciones de la atención que en los no refractarios (NR), evaluados a través de la amplitud del P300 y la ejecución en un paradigma odd-ball con letras como estímulo; 2. Si las alteraciones en el reconocimiento emocional notificadas en los esquizofrénicos se pueden reflejar a través de un paradigma semejante al de letras, especialmente en los refractarios, y 3. Si existe una correlación entre la amplitud del P300 y el grado de psicopatología en ambos subgrupos de pacientes esquizofrénicos. Pacientes y métodos. Se evaluó la ejecución y la amplitud del P300 ante una tarea de letras (TL) y otra semejante de reconocimiento de emociones faciales (EF) bajo un paradigma oddball, en 10 controles normales (CO), 10 NR y 10 RE. Resultados. El tiempo de reacción fue mayor en ambas tareas y en TL, la amplitud del P300 fue menor en NR y RE que en los CO. En EF los RE mostraron menor número de aciertos y mayor de omisiones que los NR y los CO, correlacionada con la dosis de neurolépticos. Únicamente en el grupo NR para EF, existió una correlación negativa entre la amplitud del P300 y las puntuaciones del BPRS y de la escala de síntomas positivos del PANSS. Conclusiones. Los resultados indican que los RE muestran alteraciones semejantes a los NR en la atención y mayores déficit en el reconocimiento emocional relacionados con la dosis de neurolépticos. En los NR, una menor amplitud del P300 estuvo relacionada con un mayor grado de psicopatología sólo en EF (AU)

Asunto(s)

RESUMEN

This study was conducted in order to compare the EEG patterns of schizophrenics who do not respond to typical neuroleptics with those who do respond under typical neuroleptic medication and a group of controls. Absolute (AP) and relative power (RP), and inter- and intrahemispheric correlations were calculated. Nonresistant schizophrenics showed lower delta RP, higher alpha 1 AP and RP and higher correlation between prefrontal areas than the resistant ones and controls. Resistant schizophrenics showed lower alpha 2 RP, lower beta 1 and beta 2 in temporal but higher beta 2 AP and RP in occipital derivations, and higher intrahemispheric correlation between Fp2 and F4 and lower between F8 and T4 than the nonresistant and controls. The resistants also showed a higher antero-posterior beta 1 and beta 2 index than the controls. We concluded that the EEG pattern showed by the nonresistants may be associated with their good neuroleptic response that was not present in the resistant schizophrenics.

Asunto(s)

RESUMEN

INTRODUCTION: Some of the processes impaired in schizophrenia are attention and emotional recognition. The aim of this study was to test: 1) if refractory schizophrenics (RS) present higher attentional deficits than non refractory (NR) evaluated through performance and the P300 amplitude in an odd ball paradigm using letters as stimuli; 2) if emotional recognition deficits in schizophrenics can be reflected by means of a similar paradigm than that used for letters, especially in RS, and; 3) if there exist a correlation between P300 amplitude and the level of psychopathology in these patients. PATIENTS AND METHODS: Performance and P300 amplitude were measured during a letter (LE) task and a similar one of facial emotion recognition (ER) applicating an odd ball paradigm, on 10 normal controls (CO), 10 NR and 10 RS. RESULTS: Reaction time was longer in both tasks and in LE, P300 amplitude was lower in NR and RS than in CO. In ER the RS showed a lower number of correct responses and higher of omissions than NR and CO, correlated with neuroleptics doses. A negative correlation between P300 amplitude and the scores of BPRS and PANSS positive symptoms scale was only found for the NR in ER. CONCLUSIONS: Present results point out that RS show similar deficits in relation to attention as NR do, but they show major deficits in emotional recognition related with neuroleptics doses. Furthermore, a lower P300 amplitude for NR was related to a higher level of psychopathology only in EF.

Asunto(s)