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1
artículo
Publicado 2017
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Composite material (AC-ZnO) was prepared by growing ZnO nanoparticles during the production of biomass based-activated carbon (AC) via the incorporation of zinc acetate in the process. Comprehensive analyses confirmed the presence of ZnO nanoparticles over the AC surface and described the particular nature of the composite adsorbent. Methylene blue (MB) equilibrium data fitted the Dubinin-Radushkevich model. The MB adsorption capacity was higher for the bare activated carbons (197.9–188.7 mg/g) than the activated carbons with ZnO nanoparticles (137.6–149.7 mg/g). The adsorption of the MB on the adsorbents is physical because the mean adsorption energy (E) is between 1.76 and 2.00 kJ/mol. Experiments that combine adsorption and photocatalysis were carried out with different loads of adsorbents and with and without UV-light exposure. Photocatalytic activity was identified mostly at the...
2
artículo
Publicado 2012
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Objective: to compare in vitro the marginal seal degree of composite resin restorations photopolomerized with L.E.D light and conventional halogen light, was the objective of this research.It was used 20 healthy molars recently extracted, in each of them, standardized dimensions class V cavities were prepared in the buccal and palatal aspects. Both cavities were filled with nanoparticles composite resin, Filteck Z350 and Single Bond adhesive (3M). Vestibular restaurations were light cured using L.E.D light, and palatal with conventional halogen light. Once restored, the molars were maintained for 48 hours at 37 °C and 100 % humidity. Samples were subjected to 1 % blue methylene solution thermocycling regimen, and then the marginal leakage degree was assessed, making a palatal-vestibule coronal cut, and the evaluation with a stereoscopic microscopy. The frequency of specimens that leakag...
3
artículo
Publicado 2012
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Objective: to compare in vitro the marginal seal degree of composite resin restorations photopolomerized with L.E.D light and conventional halogen light, was the objective of this research.It was used 20 healthy molars recently extracted, in each of them, standardized dimensions class V cavities were prepared in the buccal and palatal aspects. Both cavities were filled with nanoparticles composite resin, Filteck Z350 and Single Bond adhesive (3M). Vestibular restaurations were light cured using L.E.D light, and palatal with conventional halogen light. Once restored, the molars were maintained for 48 hours at 37 °C and 100 % humidity. Samples were subjected to 1 % blue methylene solution thermocycling regimen, and then the marginal leakage degree was assessed, making a palatal-vestibule coronal cut, and the evaluation with a stereoscopic microscopy. The frequency of specimens that leakag...
4
artículo
Publicado 2016
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Among 23 extracts of medicinal and edible plants tested, Mauritia flexuosa L.f., Arecaceae, showed significant antioxidant ability (DPPH and ORAC = 1062.9 and 645.9 ± 51.4 μg TE/mg extract, respectively), while Annona montana Macfad., Annonaceae, demonstrated the most promising anti-proliferative effect (IC50 for Hep-G2 and HT-29 = 2.7 and 9.0 μg/ml, respectively). However, combinatory antioxidant/anti-proliferative effect was only detected in Oenocarpus bataua Mart., Arecaceae (DPPH = 903.8 and ORAC = 1024 μg TE/mg extract; IC50 for Hep-G2 and HT-29 at 102.6 and 38.8 μg/ml, respectively) and Inga edulis Mart., Fabaceae (DPPH = 337.0 and ORAC = 795.7 μg TE/mg extract; IC50 for Hep-G2 and HT-29 at 36.3 and 57.9 μg/ml, respectively). Phenolic content was positively correlated with antioxidant potential, however not with anti-proliferative effect. None of these extracts possessed tox...
5
objeto de conferencia
21st LACCEI International Multi-Conference for Engineering, Education, and Technology: “Leadership in Education and Innovation in Engineering in the Framework of Global Transformations: Integration and Alliances for Integral Development”, Hybrid Event
6
artículo
Publicado 2021
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We thank the Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT) del Consejo Nacional de Ciencia Tecnología e Innovación Tecnologica (CONCYTEC-Perú) Grants Nº 110 -2018 - FONDECYT, for financial support to this study. The authors thank the Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (CYTED) for providing the framework.
7
artículo
Publicado 2010
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This study aimed to characterize the chemical components of essential oil of Citrus sinensis L., determine its antibacterial activity and make dosageforms, mainly for local use. The essential oil was obtained from the dried leaves of the selected species, using a hydrodistillation system with water steam sweep; tests were conducted miscibility and determination of physical constants, such as specific gravity, refractive index and optical rotation. The chemical composition was determined by Gas Chromatography/Mass Spectrometry (CG/EM), standing out in the sugiero: chromatogram spectral signals in the elucidating: Limonene, beta-linalool, decanal and 2 (10)-pinene(1S,5S)-(-)-. The determination of antibacterial activity in vitro was tested by agar diffusion method and the formation of inhibition halos against strains of Gram (+), as Staphylococcus aureus ATCC 25,933 and Staphylococcus epid...
8
artículo
Publicado 2010
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This study aimed to characterize the chemical components of essential oil of Citrus sinensis L., determine its antibacterial activity and make dosageforms, mainly for local use. The essential oil was obtained from the dried leaves of the selected species, using a hydrodistillation system with water steam sweep; tests were conducted miscibility and determination of physical constants, such as specific gravity, refractive index and optical rotation. The chemical composition was determined by Gas Chromatography/Mass Spectrometry (CG/EM), standing out in the sugiero: chromatogram spectral signals in the elucidating: Limonene, beta-linalool, decanal and 2 (10)-pinene(1S,5S)-(-)-. The determination of antibacterial activity in vitro was tested by agar diffusion method and the formation of inhibition halos against strains of Gram (+), as Staphylococcus aureus ATCC 25,933 and Staphylococcus epid...
9
artículo
Publicado 2021
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In this work, the optical and electronic properties of a TiO2/graphene oxide quantum dots (GOQDs) composite were studied by experimental and computational methods. The experimental procedures were made on TiO2 and GOQDs nanoparticles synthesized by a sol-gel method and one-pot electrochemical carbonization, respectively. The characterization of these materials and the TiO2/GOQDs composite was made using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron microscopy (XPS), FT-IR spectroscopy, and dynamic light scattering (DLS). The experimental measurements of the optical properties of these materials by UV–Vis absorption spectroscopy indicate that the addition of GOQDs promotes the expansion of the radiation absorption of TiO2 towards the visible range. Similarly, photoelectrochemical tests performed to determine the electronic properties ...
10
tesis de grado
Publicado 2022
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La desionización capacitiva (CDI) es una tecnología que consiste en la electrosorción de especies iónicas provenientes de un electrolito el cual se encuentra contenido entre dos electrodos muy próximos y en presencia de un campo eléctrico. Para la construcción de un módulo o dispositivo de desalinización de agua, basado en desionización capacitiva, se fabricaron dos tipos de electrodos: uno de carbón activado y otro de carbón activado con óxido de zinc, el proceso de fabricación consiste en la conformación de una película sobre una lámina de grafito. Las características más relevantes de los electrodos tales como su morfología, superficie específica, capacitancia, resistencia eléctrica laminar, porosidad, etc. son estudiadas y analizadas con el uso de diversas técnicas, logrando establecer una clara distinción en las propiedades que corresponden a cada tipo electr...
11
artículo
Publicado 2022
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In our study, the cathodic material xLi2MnO3–(1−x)LiNi0.5Mn0.5O2 was synthesized by means of the co-precipitation technique. The effect of x (proportion of components Li2MnO3 and LiNi0.5Mn0.5O2) on the structural, morphological, and electrochemical performance of the material was evaluated. Materials were structurally characterized using X-ray diffraction (XRD), and the morphological analysis was performed using the scanning electron microscopy (SEM) technique, while charge–discharge curves and differential capacity and impedance spectroscopy (EIS) were used to study the electrochemical behavior. The results confirm the formation of the structures with two phases corresponding to the rhombohedral space group R3m and the monoclinic space group C2/m, which was associated to the components of the layered material. Very dense agglomerations of particles between 10 and 20 µm were also ...
12
tesis de maestría
El sillico (Si) es considerado uno de los candidatos que puede reemplazar al grafito en ánodos de baterías de ion litio debido a su capacidad para almacenar mayor energía y, por ende, de mejorar sus rendimientos. No obstante, el alto estrés mecánico causado por su alta variación volumétrica durante los ciclos de carga y descarga sumado a su baja conductividad eléctrica viene siendo un impedimento para su amplio uso. Por tal motivo, los composites a base de silicio son estudiados en esta tesis con el fin de mejorar su viabilidad comercial. Este trabajo de investigación se enfoca en la síntesis de composites MXeno Ti3C2 - silicio como ánodos para baterías de iones de litio así como su caracterización electroquímica. El MXeno Ti3C2 es un material dos dimensional cuya buena resistencia mecánica y conductividad pueden aportar a solucionar los problemas de los ánodos de Si. La...
13
tesis de maestría
El sillico (Si) es considerado uno de los candidatos que puede reemplazar al grafito en ánodos de baterías de ion litio debido a su capacidad para almacenar mayor energía y, por ende, de mejorar sus rendimientos. No obstante, el alto estrés mecánico causado por su alta variación volumétrica durante los ciclos de carga y descarga sumado a su baja conductividad eléctrica viene siendo un impedimento para su amplio uso. Por tal motivo, los composites a base de silicio son estudiados en esta tesis con el fin de mejorar su viabilidad comercial. Este trabajo de investigación se enfoca en la síntesis de composites MXeno Ti3C2 - silicio como ánodos para baterías de iones de litio así como su caracterización electroquímica. El MXeno Ti3C2 es un material dos dimensional cuya buena resistencia mecánica y conductividad pueden aportar a solucionar los problemas de los ánodos de Si. La...
14
objeto de conferencia
Publicado 2008
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In the Central Andes of Peru, four volcanic arcs, termed Tacaza, Lower and Upper Barroso, and Frontal arc, have been active over the past 30 Ma (Fig. 1). They form five units between Moquegua and Nazca (14°30– 17°15’°S and 70–74°W). The ‘Neogene ignimbrites’ (<25 Ma) comprise six generations of widespread sheets (>500 km2 and >20 km3 each), representing a major crustal melting event, triggered by thickening and advective heat input from the mantle wedge. Also, four generations of edifices (i.e shields, composite cones, and dome clusters) and monogenetic fields mostly overly the ignimbrites based on ages, stratigraphy and mapping.
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16
tesis de grado
Publicado 2025
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Objetivo: en esta revisión sistemática tenemos como objetivo general analizar la información científica disponible en las bases de datos sobre los compuestos fitoquímicos y actividades farmacológicas de la Guanábana (Annona muricata) de interés farmacéutico. Materiales y métodos: se ha empleado el método de enfoque mixto entre cualitativos y cuantitativos, no experimental y de enfoque analítico-sintético. Se realizó una revisión sistemática vía web donde se recopiló y analizó la información sobre los estudios fitoquimicos y farmacológicos de la especie Annona muricata (guanábana), empleando fuentes primarias de bases de datos electrónicos como Scielo, ScienceDirect, PubMed, BiomedCentral, Scopus y Redalyc. Resultados: los componentes fitoquímicos más frecuentes de la especie de Annona muricata son flavonoides, alcaloides, taninos, fenoles, terpenos, saponina, glu...
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objeto de conferencia
1 página (Abstract) | Trabajo presentado en General Assembly, International Association of Volcanology and Chemistry of the Earth’s Interior, IAVCEI, Reykjavik, Island, 2008.
18
artículo
Publicado 2020
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The article examines the development of speech in elementary school students. The research objective is to determine the status of coherent speech development in 3rd-grade students in the process of constructive and artistic activity. The article defines the criteria (structural and compositional, communicative and productive, and communicative and creative), indicators, and levels of development of coherent speech in elementary school students in the process of constructive and artistic activity. Each criterion includes a group of qualitative content-disclosing indicators and characterizes the achievements of students in the intended type of activity. Based on this, the authors have developed a methodological tool that allows them to diagnose coherent speech development in 3rd-grade students in the process of constructive and artistic activity and to conduct a precise quantitative diffe...
19
artículo
Publicado 2021
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Purpose. The purpose of this paper is to examine whether cross-country differences in pensionable age explain such differences in economic activity of people at near-retirement age. Design/methodology/approach. The empirical study uses regression models for macro-panel encompassing 21 European countries in the period 2008–2014. Findings. Empirical results indicate that pensionable age is a determinant of cross-country differences in employment rate in the near-retirement age group, and less a factor differentiating average effective retirement age. It turns out that other factors matter, including salaries and wages as percentage of GDP (treated as a proxy for the occupational composition of populations across the countries studied), self-employment, participation in education and training, or self-perceived health. Social implications. The problem of economic activity at the near-reti...
20
artículo
Publicado 2020
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The article examines the development of speech in elementary school students. The research objective is to determine the status of coherent speech development in 3rd-grade students in the process of constructive and artistic activity. The article defines the criteria (structural and compositional, communicative and productive, and communicative and creative), indicators, and levels of development of coherent speech in elementary school students in the process of constructive and artistic activity. Each criterion includes a group of qualitative content-disclosing indicators and characterizes the achievements of students in the intended type of activity. Based on this, the authors have developed a methodological tool that allows them to diagnose coherent speech development in 3rd-grade students in the process of constructive and artistic activity and to conduct a precise quantitative diffe...
