Nanoscale Perovskite-Sensitized Solar Cell Revisited: Dye-Cell or Perovskite-Cell?

A general and straightforward way of preparing few-nanometer-sized well-separated MAPbIx Br3-x (MA=methylammonium) perovskite photosensitizers on the surface of an approximately 1 µm thick mesoporous TiO2 photoanode was suggested through a two-step sequential deposition of low-concentrated lead halides (0.10-0.30 m PbI2 or PbBr2 ) and methylammonium iodide/bromide (MAI/MABr). When those nanoscale MAPbIx Br3-x perovskites were incorporated as a photosensitizer in typical solid-state dye-sensitized solar cells (ss-DSSCs), it could be verified clearly by the capacitance analysis that nano-particulate MAPbI3 perovskites play the same role as that of a typical dye sensitizer (MK-2 molecule) although their size, composition, and structure are different.

Aproximación al desempeño operativo de un modelo de redes neuronales en el diagnóstico de la infertilidad masculina / Approach to operational performance of a neuronal network model in the diagnosis of male infertility

Objetivo: realizar una aproximación a la capacidad de las redes neuronales supervisadas para clasificar lizando los parámetros seminales convencionales. Materiales y métodos: estudio de corte transversal ensamblado sobre la base de datos del Grupo Reproducción de la Universidad de Antioquia, en el que se escogieron hombres con problemas re-productivos en los doce meses previos y hombres con antecedente de haber tenido hijos. Muestreo por conveniencia. Se tomaron en cuenta: la edad, el tiempo de abstinencia sexual, el volumen del eyaculado, el pH, los porcentajes de movilidad y de viabilidad, y la concentración espermática. Mediante una red neuronal supervisada se desarrolló un modelo de entrenamiento y un modelo de validación. Resultados: se incluyeron 204 hombres. Para el modelo de entrenamiento 129 hombres, 35 para la validación, 40 para probar el modelo y 25 para la validación externa. En el modelo de la red neuronal clasificó adecuadamente el 90% de los sujetos con problemas reproductivos y el 91% de los sujetos cuadamente el 40% de los sujetos con problemas reproductivos y el 100% de los sujetos fértiles. Conclusión: las redes neuronales surgen como una tecnología que podría ser valiosa para el estudio de la infertilidad masculina. Se requieren evaluaciones más rigurosas para definir su real utilidad en el estudio de la pareja infértil

Objective: To determine the ability of supervised neuronal networks at making the appropriate classification of fertile and infertile men using conventional seminal parameters. Materials and methods: Cross-sectional study assembled on the database of the Universidad de Antioquia Reproduction Group, with a selection of men experiencing reproductive problems within the previous 12 months, and men with a history of having had children. Convenience sampling. The data considered were age, time of sexual abstinence, ejaculate volume, pH, percentage of sperm motility, viability and concentration. Using a supervised neuronal network, a training model and a validation model were created. Results: Overall, 204 men were included, 129 for the training model, 35 for validation, 40 for testing the model and 25 for external validation. The neuronal network model made the correct classification of 90% of the subjects with reproductive problems, and 91% of the fertile subjects. In the validation model, the neuronal network made the correct classification of 40% of the subjects with reproductive problems, and 100% of the fertile subjects. Conclusion: Neuronal networks emerge as a technology that may prove to be valuable for the study of male infertility. More rigorous evaluations are required in order to determine their true usefulness in the study of infertile couples