This study aimed to determine endocrine disruptors in urbanized rivers Maracanã and Mangue Channel in Rio de Janeiro the second most populated city in Brazil. Bisphenol A, 17β-estradiol, estriol, and 17α-ethinylestradiol were determined by high-performance liquid chromatography with a diode array detector and fluorescence detector In addition, the evaluation of estrogenic activity was performed by the YES bioassay (Yeast estrogen screen) with the Saccharomyces cerevisiae yeast, and acute toxicity assays were performed using Daphnia similis and Vibrio fischeri. Estrogenic activity in the water samples ranged from below the limit of detection (<LD) to 1.6 ng L-1, while bisphenol A ranged from 22.3 to 1325.2 ng L-1 and estrogens 17β-estradiol from <LD to 55.2 ng L-1, estriol from <LD to 313.7 ng L-1 and 17α-ethinylestradiol, from <LD to 409.4 ng L-1. The acute toxicity was not detected in both analyzed organisms. The present study indicates a serious level of pollution by the compounds evaluated with significant risks to the aquatic ecosystem, mainly for Guanabara Bay which receives urbanized river discharge. Therefore, recommending the need for systematic monitoring and mitigating actions in these water bodies.
Colloidal quantum dots (QDs) are of great interest in optoelectronic and photovoltaic devices with low-cost processing, strong light absorption, and size tunable direct band gap. However, their limited carrier mobility and short diffusion length limit efficient charge collection and transport. The short diffusion length in QD solid films, 100-200 nm, limits their thickness to t≈200-300 nm, resulting in poor absorption in the near-infrared, λ>800 nm, wasting part of sunlight and reducing power conversion efficiency. Recently, a novel architecture based on multiple graphene monolayers (Gr) intercalated inside QD films was reported to improve charge extraction beyond QDs diffusion length. The intercalated graphene layers ensure efficient charge collected in QD films thicker than the diffusion length. However, this architecture still fails to collect carriers from the QDs when the thickness is >∼200 nm due to the poor vertical conductivity of the devices. Herein, we present the fabrication, optimization, and implementation of intercalated devices with vertical interconnecting contacts, increasing carrier collection, and photocurrent, aiming to develop a novel architecture for improved photodetection and photovoltaics with QDs. First, we analyze the individual roles of Gr and QDs, studying the evolution of light absorption, photocurrent (I ph ), and conductivity as successive QD and Gr layers are added. We find the optimal interspacing between graphene layers in the intercalated system, aiming for the best compromise between light absorption and efficient charge collection. Our main contribution is the implementation of vertical interconnect access (VIAs) to each graphene layer to ensuring efficient charge transfer from Gr to the gold electrical contacts for efficient current collection. We show that for 850 nm wavelength illumination, photocurrent of intercalated devices show a ∼10 fold improvement over devices without VIAs. We also use a back-gate voltage to monitor Fermi level shift in Gr and charge transfer from QDs to Gr. The intercalated configuration with VIAs contacts herein presented is a significant improvement in charge collection for QD optoelectronic applications as well as a promising architecture to enhance the power conversion efficiency for QD solar cells.
Introducción: La Electromiografía-EMG de superficie evalúa la función muscular. Es poco utilizada como examen de rutina para valorar los músculos periorales y masticatorios, debido a que algunos consideran que puede ser molesto para el paciente pediátrico. Objetivo: Describir la percepción de dolor y el comportamiento en niños colombianos con y sin labio y paladar fisurado durante el examen de electromiografía de superficie en músculos periorales y masticatorios. Métodos: Previa aprobación del comité de ética (acta-009 2013p) y firma de consentimiento y asentimiento informado. Se realizó el examen en 69 niños entre 5-15 años: 45 con labio y paladar hendido (23-fisura unilateral, 22-fisura bilateral) y 24 sin hendidura. Se aplicaron las escalas de Wong Baker (Dolor) y Frankl (comportamiento). Resultados: 66 niños (95,65%) presentaron comportamiento Tipo 4 y 3 niños (4,35%) mostraron comportamiento Tipo 3 al inicio del examen. Al final del procedimiento, el 100% presentó comportamiento tipo 4. La percepción del dolor con la escala Wong Baker mostro ningún dolor en 62 niños (89,86%) y solo un poco de dolor en 7 (10,14%). Conclusiones: Los menores no manifiestan cambios importantes en su comportamiento por dolor o molestias durante el procedimiento de electromiografía de superficie.
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