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Due to the high solar radiation, constant over the whole year, solar energy is one of the most promising energy sources of the Caribbean for the next decades. But up to now this potential is not used, mainly due to the high costs of solar cells. Solar energy conversion is mainly dominated by expensive cells based on silicon. A promising alternative is the dye sensitized solar cell (DSSC) based on Titanium dioxide (TiO2), which has generated considerable interest in the last years. Thus, the objective of this study was to analyse and optimize the DSSCs’ performance depending on their preparation and lighting condition. Therefore, five different natural dyes were extracted from local Colombian fruits and vegetables, such as Achiote, Agraz, Corozo, Mora and Remolacha. They were characterized using an UV-Spectrophotometer and used as sensitizers to fabricate the DSSCs. To optimize the DSSCs, different conditions and parameters were changed. It was thereby found that beside the fruit that was used, also the thickness of the TiO2 layer and the preparation procedure of the dye solution have a direct impact on the cell efficiency. The cells fabricated with achiote dye solution were found to have the best efficiency, reaching up to 0,21% under sun and 0,075% under a halogen lamp. The study was executed in the context of internships at the Universidad del Norte in Barranquilla, Colombia, which was enabled by the DAAD through RISE program scholarships. Resumen La energía solar es una de las más promisorias fuentes de energía en el Caribe en las próximas décadas debido a la alta radiación solar y a que se mantiene muy constante durante la mayor parte del año. Sin embargo, hasta ahora este potencial no se usa debido a los altos costos de las celdas solares, cuya comercialización está principalmente dominada por costosas celdas basadas en silicio. Una alternativa prometedora son las celdas solares sensibilizadas con colorantes (DSSC, por sus siglas en inglés) basadas en dióxido de titanio (TiO2), las cuales han generado bastante interés en los últimos años. Así, el objetivo del presente estudio fue analizar y optimizar el desempeño de las DSSC dependiendo de su preparación y condiciones de iluminación. Por ello se usaron cinco colorantes naturales diferentes extraídos de frutas y vegetales, tales como: Achiote, Agraz, Corozo, Mora y Remolacha. Estos colorantes fueron caracterizados usando un espectrofotómetro en ultravioleta y visible, y usados como sensibilizadores en la fabricación de las DSSC. En el proceso de optimización se cambiaron varias condiciones y parámetros. En ello se encontró que además de los colorantes usados, los grosores de las capas del TiO2 y los procedimientos de preparación de la solución colorante tienen un impacto directo en la eficiencia de las celdas. Finalmente, se encontró que las celdas con las mejores eficiencias fueron las de Achiote, cuya eficiencia alcanzó el 0,21% bajo iluminación directa del sol y de 0,075% de eficiencia cuando fue iluminada con una lámpara halógena. Este estudió se desarrolló en el contexto de intercambios académicos en la Universidad del Norte con el apoyo del DAAD a través del programa RISE. Résumé L’énergie solaire est l’une des sources d’énergie les plus prometteuses dans les Caraïbes, pour les décennies à venir, dû au rayonnement solaire élévé qui reste constante pendant la majeure partie de l’année civile. Cependant, jusqu’à présent ce potentiel n’a pas été pleinement exploité, en raison de coût élevé des cellules solaires, dont la commercialisation a été dominée par des cellules de silicium à prix élevé. Une solution prometteuse sont les cellules solaires sensibilisés par un colorant (DSSC, en anglais), à base de dioxyde de titane (TiO2.), qui a suscité des réactions considérables pour ces dernières années. Donc, l’objectif principal de cette étude était d’analyser et d’optimiser la performance de DSSC, en fonction de de ses conditions de préparation et d’illumination. Ainsi, cinq colorants naturels ont été utilisés, de fruits et végétaux extraits, à partir d’Achiote, Agraz, Corozo, Mûr et de Betteraves. Ces colorants ont été caractérisés en utilisant un spectrophotomètre, dans l’ultraviolet et le spectre visible, et utilisés des comme sensibilisants, pour la fabrication des DSSC. Dans le processus d’optimisation des diverses conditions et paramètre ont été changés. En cela il a été établi qu’en plus des colorants utilisés, les épaisseurs de couche du TiO2. et les processus de préparation de solution colorante ont un impact direct sur la efficacité des cellules. On se retrouva finalement que les cellules avec les meilleures efficacités ont été celles de l’Achiote, dont une efficacité du 0,21% a été atteint, avec un éclairage de la lumière directe du soleil, et une efficacité du 0,075%, lorsqu’elle est éclairée par une lampe halogène. Cette étude a été élaboré dans le contexte d’échanges universitaires dans l’Universidad del Norte appuyée par le service allemand d’échanges universitaires (DAAD), à l’aide du programme RISE. Resumo A energia solar é uma das fontes de energia mais promissores no Caribe, nas próximas décadas, devido à alta radiação solar que se mantém constante durante a maior parte do ano. No entanto, até agora este potencial não é usado por causa do alto custo das células solares, cuja comercialização é dominada principalmente por células de silício de preço elevado. Uma alternativa promissora são as células solares sensibilizadas por corante (DSSC, por sua sigla em Inglês) à base de dióxido de titânio (TiO2), que geraram um interesse considerável nos últimos anos. Assim, o objetivo deste estudo foi analisar e aperfeiçoar o desempenho de DSSC dependendo de suas condições de preparação e de iluminação. Assim, foram usados cinco diferentes corantes naturais extraídos de frutos e vegetais, tais como: Anato, Agraz, Corozo, Mora e Beterrabas. Estes corantes foram caracterizados usando um espectrofotómetro de ultravioleta e visível, e utilizados como sensibilizadores na fabricação do DSSC. No processo de optimização várias condições e parâmetros foram alterados. Verificou-se que a adição dos corantes utilizados, as espessuras das camadas de TiO2. e métodos de preparação da solução de corante tem um impacto direto sobre a eficiência das células. Finalmente descobriu-se que as células com as melhores eficiências foram anato, cuja eficiência de 0,21% com iluminação solar direta e eficiência de 0,075% quando foi iluminado com uma lâmpada de halogéneo. Este estudo foi desenvolvido no contexto do intercâmbio acadêmico com a Universidad del Norte e apoiado através do programa RISE.

The chemisorption of maleic anhydride on Si(100)-2×1 at room temperature has been studied with scanning tunneling microscopy (STM). We observe that, at low coverages below 0.12 monolayer, the unsat...

Summary Problems encountered in the psychotherapeutic management of severely disturbed patients are examined. Although “human interest” has its role to play in the care of chronic psychotic patients, this paper attempts to delineate and reaffirm the necessity for specific diagnosis and treatment techniques which rely on the concepts of patient and therapist adaptations. “Adaptive psychotherapy” is defined, its theoretical basis outlined, its goals and principles described and clinical vignettes of its techniques are presented.

Summary This communication summarizes a seven year experiment in teaching adaptive psychotherapy. The patient population involved is chronically and severely ill and requires ongoing indefinite contacts on an intermittent or continuing basis. A clinic is described which provides opportunities for a brief socialization experience and individual, marital, and family psychotherapy. The structure of the clinic is such that the supervisor-administrator has maximum opportunities for teaching interventions. Most trainees have many preconceptions and prejudices about the difficulties and the efficacy of adaptive psychotherapy. Although some of these misgivings are rational and concerned with usual learning tasks, part of the problems arise from anxiety associated with the need for different behavior than that previously utilized by the therapist in “psychotherapy.” In particular, rapid dynamic assessment of the disabling problem, the capacity to reach therapeutic decisions with limited information, the management of very sick individuals, and an active approach are important training elements in the T.A.C. Such experiences early and late in residency training with appropriate supervision have usually enabled the trainee to acquire his own style of interventions appropriate to this type of patient and this kind of therapy.

Background The corpus luteum (CL) is a transient endocrine gland and prostaglandin F2-alpha is considered to be the principal luteolysin in pigs. In this species, the in vivo administration of prostaglandin F2-alpha induces apoptosis in large vessels as early as 6 hours after administration. The presence of the prostaglandin F2-alpha receptor (FPr) on the microvascular endothelial cells (pCL-MVECs) of the porcine corpus luteum has not yet been defined. The aim of the study was to assess FPr expression in pCL-MVECs in the early and mid-luteal phases (EL-p, ML-p), and during pregnancy (P-p). Moreover, the effectiveness of prostaglandin F2-alpha treatment in inducing pCL-MVEC apoptosis was tested. Methods Porcine CLs were collected in the EL and ML phases and during P-p. All CLs from each animal were minced together and the homogenates underwent enzymatic digestion. The pCL-MVECs were then positively selected by an immunomagnetic separation protocol using Dynabeads coated with anti-CD31 monoclonal antibody and seeded in flasks in the presence of EGM 2-MV (Microvascular Endothelial Cell Medium-2). After 4 days of culture, the cells underwent additional immunomagnetic selection and were seeded in flasks until the confluent stage. PCR Real time, western blot and immunodetection assays were utilized to assess the presence of FPr on pCL-MVEC primary cultures. Furthermore, the influence of culture time (freshly isolated, cultured overnight and at confluence) and hormonal treatment (P4 and E2) on FPr expression in pCL-MVECs was also investigated. Apoptosis was detected by TUNEL assay of pCL-MVECs exposed to prostaglandin F2-alpha. Results We obtained primary cultures of pCL-MVECs from all animals. FPr mRNA and protein levels showed the highest value (ANOVA) in CL-MVECs derived from the early-luteal phase. Moreover, freshly isolated MVECs showed a higher FPr mRNA value than those cultured overnight and confluent cells (ANOVA). prostaglandin F2-alpha treatment failed to induce an apoptotic response in all the pCL-MVEC cultures. Conclusion Our data showing the presence of FPr on MVECs and the inability of prostaglandin F2-alpha to evoke an in vitro apoptotic response suggest that other molecules or mechanisms must be considered in order to explain the in vivo direct pro-apoptotic effect of prostaglandin F2-alpha at the endothelial level.