In the present work, the first results of the biopolymers obtained from the starches extracted from potatoes and cassava are presented, these were analyzed by the IR spectroscopy technique, observing that in both cases they present the same starch characteristics, so potato starch was chosen because it is a From this starch films with an approximate thickness of 50 microns were obtained, which were characterized by elongation and tensile techniques with maximum elongation values of 62% and a maximum tensile force of 10 Newton, it was also characterized by IR spectroscopy finding the peaks Characteristic of cellulose, the films have a high transmittance in the visible range, atomic absorption analyses show the harmlessness of the films obtained.

Nanocrystalline TiO2 films, surface modified with Al3+, were manufactured by depositing a TiO2 suspension containing small amounts of aluminum nitrate or aluminum chloride onto conducting glass substrates, followed by drying, compression, and finally heating to 530 °C. Electrodes prepared with TiO2 nanoparticles coated with less than 0.3 wt % aluminum oxide with respect to TiO2 improved the efficiency of the dye sensitized solar cell. This amount corresponds to less than a monolayer of aluminum oxide. Thus, the Al ions terminate the TiO2 surface rather than form a distinct aluminum oxide layer. The aluminum ion surface treatment affects the solar cell in different ways: the potential of the conduction band is shifted, the electron lifetime is increased, and the electron transport is slower when aluminum ions are present between interconnected TiO2 particles.

El interés por las nanopartículas de plata (AgNPs) se debe a sus propiedades ópticas, catalíticas y antibacterianas; las cuales dependen de su tamaño, forma y estabilidad coloidal. Las AgNPs pueden ser obtenidas mediante técnicas químicas, físicas y biológicas; sin embargo, el enfoque de “Química Verde” promueve el desarrollo de investigaciones que no incluyan sustancias tóxicas o condiciones de costo elevado en la síntesis de nanopartículas, una alternativa es el uso de extractos de plantas, algas, hongos, bacterias y virus como agentes reductores y estabilizantes en el proceso de síntesis. Por tal motivo esta investigación emplea extractos etanólicos pétalos y hojas de t para la obtención de AgNPs con un tamaño de partícula menor a 50 nm. Mediante UHPLC‑ESI-Q-Orbitrap-MS-MS se identificaron los metabolitos secundarios mayoritarios presentes en los extractos et...

En los meses de agosto y setiembre de 1998, en las localidades de Viscas (distrito Quinocay) y Huanochicchi (distrito de Viñac) en la provincia de Yauyos (Lima), ocurrieron brotes de Bartonelosis. Es así que los grupos de Intervención Rápida, a solicitud de la Dirección de Servicios Básicos de Salud Cañete- Yauyos, realizaron un trabajo de campo en el Distrito de Viñac, localidad de Huanochicchi entre los días lro. y 3 de setiembre de 1998 y un segundo grupo de Intervención Rápida en el distrito de Quinocay, localidad de San Juan de Viscas.

El presente trabajo de investigación se llevó a cabo entre setiembre del 2015 y febrero del 2016, en el distrito de Cerro Colorado (Alto Cural – Lateral 6) en un campo comercial de cebolla cv. “Roja Perilla”. El objetivo del presente trabajo fue evaluar la efectividad de insecticidas químicos y de origen biológico para el control de trips (thrips tabaci L.) en el cultivo de cebolla (allium cepa L.). El diseño estadístico empleado fue bloques completamente al azar (DBCA), con 4 bloques y 7 tratamientos, haciendo un total de 28 unidades experimentales. Los tratamientos fueron: spinosad (100 ml), spinosad (125 ml), spinosad (80 ml) + clorpirifos (500 gr), spinosad (100 ml) + clorpirifos (500 gr), spinosad (125 ml) + clorpirifos (500 gr) y clorpirifos (500 gr) respectivamente. Además, se utilizó el testigo químico lambdacyhalothrin (125 ml) + profenofós (300 ml). Para la apli...

17 p.

Se ha desarrollado un prototipo que puede monitorear la calidad del agua en tiempo real cuyo principio es la “lengua electrónica”. Los principios del sistema son métodos electroquímicos, involucra la combinación de varios sensores electroquímicos no selectivos (electrodos de metales), el procesamiento y tratamiento de las señales, y un algoritmo de reconocimiento de patrones. Los patrones son únicos para cada muestra líquida y son interpretados con un análisis de componentes principales. El sistema determina atributos (calidad, estado del proceso, etc.) antes que parámetros simples. El prototipo es portátil y ha evaluado la calidad del agua de consumo humano en una zona rural (Yaurisque, Cusco). El sistema ha logrado discriminar agua con diferentes composición química y bacteriológica.

Optimized thin films composed of ZnO nanorods, grown after preliminary electrodeposition and successively coated with 3 layers of TiO2 and decorated with Ag2Se nanoparticles, were prepared onto glass FTO wafers to treat oxytetracycline solutions by photoelectrocatalysis (PEC). The coatings were thoroughly characterized by XRD, Raman and UV/Vis diffuse reflectance spectroscopy, confocal microscopy, FE-SEM, HRTEM, EDX and XPS. The synthesized films had a mean thickness of 1.19 mu m, length >500 nm and a bandgap of 1.85 eV, being visible-light photoactive. Good stability and reproducibility was obtained when treating 5 mg dm(-3) oxytetracycline solutions in 0.050 M Na2SO4 at pH 5.8, attaining 96.5% antibiotic decay after 360 min at an anodic potential of +1.0 V vs Ag vertical bar AgCl under irradiation with a 36-W blue LED lamp. Comparative photocatalysis and electrochemical oxidation treat...

Here, we demonstrate the viability of a ZnO/TiO2/Ag2Se thin-film composite synthesized on FTO to degrade the drug naproxen in aqueous solutions by visible-light photoelectrocatalysis (PEC). The experiments were made with 100 mL of solutions containing 5 mg L-1 drug and 50 mM Na2SO4 at natural pH, using a cell equipped with a Pt wire as cathode and the composite as photoanode exposed to a 36 W blue LED lamp. Total degradation was achieved after 210 min of electrolysis at anodic potential of +1.0 V/Ag vertical bar AgCl. This resulted from the oxidative action of hydroxyl radicals formed via direct anodic water discharge and through mediated water oxidation by photogenerated holes. The degradation rate decreased at higher naproxen concentration, but the treatment efficiency became higher due the deceleration of the parasitic reactions involving hydroxyl radicals. In chloride medium, the pho...

A prototype has been developed that could monitor the water quality in real time based on an “electronic tongue”. The system is based on electrochemical methods and involves the combination of non-selective sensors (metal electrodes), the signal processing part, and a pattern recognition. It determines attributes (quality, status of a process, etc.) rather than single parameters. Unique response patterns for liquid samples are interpreted with principal components analysis. The prototype is portable and has evaluated the water quality in a rural area (Yaurisque, Cusco). The system could discriminate water with different chemical and bacterological composition.

Estructuras unidimensionales (1D) mesoporosas tipo nanotubos/nanobarras de TiO fueron 2 sintetizadas por el método hidrotermal en medio alcalino, empleando como material de inicio nanopartículas de TiO obtenidas por el proceso Sol Gel (SG-TiO ). Imágenes obtenidas por 2 2 Microscopía Electrónica de Barrido por Emisión de Campo (MEB-EC) y Microscopía Electrónica de Transmisión de Alta Resolución (MET-AR) mostraron la formación de nanoestructuras tipo tubo de 8 nm de diámetro y tamaños mayores a 400 nm de largo luego del tratamiento hidrotermal de 18 y 24 horas; éstas nanoestructuras se conservaron luego del proceso de intercambio iónico con ácido clorhídrico (HCl). Luego de la calcinación, se convirtieron a estructuras tipo barras de TiO anatasa como lo muestran los resultados 2 obtenidos por Difracción de Rayos X (DRX). La conversión de nanopartículas a nanotubos y p...

The wide use of the fluoroquinolone antibiotic ciprofloxacin (CIP), combined with its limited removal in wastewater treatment plants, results in a dangerous accumulation in natural water. Here, the complete degradation of CIP by photoelectrocatalysis (PEC), using an FTO/ZnO/TiO2/Ag2Se photoanode that is responsive to blue light, has been investigated. A slow antibiotic concentration decay was found in 0.050 M Na2SO4 under the oxidizing action of holes and radical dotOH photogenerated at the anode surface. The degradation was strongly enhanced in 0.070 M NaCl due to mediated oxidation by electrogenerated active chlorine. The latter process became faster at pH 7.0, with total abatement of CIP at concentrations below 2.5 mg L−1 operating at a bias potential of +0.8 V. The performance was enhanced when increasing the anodic potential and decreasing the initial drug content. The use of sola...

The work described in this paper was financially supported by the National Fund for the Scientific and Technological Development (FONDECYT), Grant No. 237–2015-FONDECYT. The authors thank Dr. Breno Pannia Espósito and the LABQAM of the Chemistry Institute of USP for the analysis of the samples. In addition, authors thank Dr. Pierre Ramos Apestegui for his excellent technical assistance with scanning electron microscopy observation.