In Situ Ethanolamine ZnO Nanoparticle Passivation for Perovskite Interface Stability and Highly Efficient Solar Cells.

Zinc oxide (ZnO) has interesting optoelectronic properties, but suffers from chemical instability when in contact with perovskite interfaces; hence, the perovskite deposited on the top degrades promptly. Surface passivation strategies alleviate this instability issue; however, synthesis to passivate ZnO nanoparticles (NPs) in situ has received less attention. Here, a new synthesis at low temperatures with an ethanolamine post treatment has been developed. By using ZnO NPs prepared with ethanolamine and butanol (BuOH), (E-ZnO), the stability of the FA0.9Cs0.1PbI3 (FACsPI)−ZnO interface was achieved, with a photoconversion efficiency of >18%. Impedance spectroscopy demonstrates that the recombination at the interface was reduced in the system with E-ZnO/perovskite compared to common SnO2/perovskite and that the quality of the perovskite on the top is clearly due to the ZnO in situ passivation with ethanolamine. This work extends the use of E-ZnO as an n-type charge extraction layer and demonstrates its feasibility with methylammonium perovskite. Moreover, this study paves the way for other in situ passivation methods with different target molecules, along with new insights regarding the perovskite interface rearrangement when in contact with the modified electron transport layer (ETL).

Prevalence and impact of primary dysmenorrhea among Mexican high school students.

OBJECTIVE: To evaluate factors affecting the prevalence of dysmenorrhea in a group of Mexican students. METHOD: A questionnaire was administered to 1152 high school students and the obtained data about severity, symptoms, and medications used were analyzed. RESULTS: Dysmenorrhea had a prevalence of 48.4% and was the cause of school absences for 24% of the affected students. It was mild in 32.9%, moderate in 49.7%, and severe in 17.4% of these students, of whom 28% consulted a physician and 60.9% self-medicated. The most common over-the-counter drugs used were a combination of paracetamol, pamabrom and pyrilamine maleate; metamizol (a nonsteroidal anti-inflammatory drug) plus butylhioscine; and naproxen. We found a significant correlation between the presence of dysmenorrhea and smoking, cycle pattern, cycle duration, flow duration, and amount of flow. CONCLUSION: The prevalence of dysmenorrhea was high in our sample. The condition caused short-term school absences and the students commonly addressed it by self-medicating.

Estudio técnico sobre manejo de residuos sólidos hospitalarios de la ciudad Ntra. Sra. de la Asunción

Estudio orientado hacia el análisis de los sistemas utilizados para el manejo de aquellos desperdicios sólidos que se producen dentro de los hospitales y sanatorios existentes en la ciudad de Ntra. Sra. de la Asunción (Paraguay), Indica un servicio de recolección, transporte y disposición final (incineradores de basuras patológicas) a todos los establecimientos asistenciales, para contribuir a: evitar el riesgo de la propagación de enfermedades infecciosas; brindar una mayor protección tanto a pacientes como a empleados del establecimiento; disminuir los costos de recolección, transporte y disposición por mejor aprovechamiento de los recursos existentes. Incluye gráfico de un sistema adecuado para su manejo, así como un proyecto sobre norma sanitaria