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Influence of Surface Modification of BaTiO3Nanoparticles by Sodium Oleate and Chitosan on their Optical Properties and Agglomeration in Aqueous Solutions
No full textSpherical titanium barium nanoparticles with an average size about 100 nm in the tetragonal crystal phase were obtained by peroxide synthesis. To prevent their agglomeration and reduce the toxic effect, the surface of nanoparticles was chemically modified with sodium oleate and chitosan. Influence of surface modification by these compounds on agglomeration of nanoparticles in aqueous solutions, their spectral features, as well as generation of the second optical harmonic were investigated.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
The spinning voltage influence on the growth of zno-rgo nanorods for photocatalytic degradation of methyl orange dye
No full textIn this work, well-designed zinc oxide-reduced graphene oxide (ZnO-rGO) nanorods (NRs) were synthesized by a hydrothermal method using electrospun ZnO-rGO seed layers. The ZnO-rGO seed layers were fabricated on fluorine-doped tin oxide (FTO) glass substrates through calcined of electrospun nanofibers at 400◦C in the air for 1 h. The nanofibers were prepared by electrospinning different spinning voltages and a spinning solution containing zinc acetate, polyvinyl pyrrolidone, and 0.2 wt% rGO. From a detailed characterization using various analytical techniques, for instance, X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS), the dependence of the structure, morphology, and optical properties of the ZnO-rGO NRs was demonstrated. The photocatalytic activities of ZnO-rGO nanorods were evaluated through the degradation of dye methyl orange (MO). The results show that the change of spinning voltages and the coupling of rGO with ZnO improved photodecomposition efficiency as compared to pure ZnO. The highest photocatalytic efficiency was obtained for the ZnO-rGO NRs prepared with a spinning voltage of 40 kV.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Proximate analysis, phenolics, betalains, and antioxidant activities of three ecotypes of kaÑiwa (Chenopodium pallidicaule aellen) from peru
No full textKañihua (Chenopodium pallidicaule Aellen, Chenopodiaceae) is a native plant from the highlands of Peru and Bolivia that is characterized by its high nutritional value. It is considered a species of great genetic diversity and in this study we evaluated the nutritional characteristics, fatty acids profile, antioxidant compounds and antioxidant activities of three kañihua ecotypes from Peru named “Chilliwa” (light grey seeds), “Planta púrpura” (light orange seeds) and “Red kañiwa Condorsaya” (red seeds).Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Influence of Dy doping on the structural, vibrational, optical, electronic, and magnetic properties of SnO2 nanoparticles
No full textDysprosium (Dy3+)-doped tin oxide (SnO2) nanoparticles (NPs) have been successfully synthesized using the chemical polymer precursor method. This material blends the holding matrix’s electronic properties with dysprosium’s optical and magnetic properties, making it a promising material for technological applications. X-ray diffraction patterns and the Raman spectra of all NPs indicated the formation of only the SnO2 phase. The decrease in particle size (from ~ 11 to ~ 6 nm) and increase in lattice parameters depending on the Dy content were determined. The latter proves the solid solution between Sn and Dy ions, which is in agreement with the ionic radii mismatch between them. Transmission electron microscopy (TEM) confirms the particle size and size reduction observed through XRD. X-ray photoelectron spectroscopy (XPS) results suggest a change of the oxidation state from Sn4+ to Sn2+with the Dy content, with more Dy3+ than the values accessed from EDS analysis. The latter strongly suggests that the Dy3+ surface gets enriched as the dopant amount increases, driving to the surface passivation of structural defects in good agreement with Raman spectroscopy results. Optical properties show a modest bandgap reduction with the Dy content. Meanwhile, magnetic measurements indicate the coexistence of ferromagnetic and paramagnetic contributions for 1% Dy-doped SnO2 NPs. However, only the paramagnetic contribution is observed after this concentration level. The ferromagnetic contribution detected for lower dopant amounts (? 1%) has been attributed to the presence of bound magnetic polarons (BMP’s). Graphical abstract: [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to Springer Nature B.V.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Enhanced antimicrobial activity of silver nanoparticles conjugated with synthetic peptide by click chemistry
No full textStrategies to design novel antibacterial materials may rely on the combination of materials to achieve synergistic effects. The coupling of antibacterial peptides to nanoparticles, however, needs to be directed conveniently to avoid structural changes within the peptide and/or degradation of the nanoparticle. Here, we present the results of the attachment of a synthetic peptide (VIHGW-alkyne-G-NH2) containing the amino terminal copper and nickel (ATCUN) motif to silver nanoparticles. In order to direct the peptide-nanoparticle coupling, the peptide was functionalized with an alkyne, whereas the nanoparticles were functionalized with azide groups using thiol-polyethylene glycol-azide (HS-PEG-N3) chains, so that the acetylide and the azide can undergo a click reaction. The reaction was conducted at room temperature and the steps in the construction of the nanoparticle-PEG-ATCUN array were followed by a combination of UV-Vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy. Evidence of the attachment of the PEG molecules through the thiol termination indicates that the nanoparticle is functionalized with azide groups, although only partially. The click reaction with the synthetic peptide is evidenced by the loss of the N3-vibrational signal with infrared spectroscopy. Throughout the steps of the synthesis, the behavior of the nanoparticles was followed by UV-Vis spectroscopy, dynamic light scattering, and zeta potential measurements, observing that during the process there are no significant changes in the size of the nanoparticle and that the stability of the nanoparticles increases. Antibacterial tests, conducted using E. coli, showed that the activity of the Ag-PEG-ATCUN nanocomposites is higher than that of nanoparticles and ATCUN peptides separately. [Figure not available: see fulltext.]. © 2020, Springer Nature B.V.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
An Approach to Temporal Phase Classification on Videos of the Volleyball's Basic Reception Technique
No full textIn this paper we provide an approach on sports analysis using Deep learning techniques. As part of a current project, the volleyball's basic reception technique has been divided into temporal phases. We performed an evaluation over our own labelled dataset consisting in 14814 frames from 69 videos depicting the desired reception technique. A model based on the YOLO algorithm was trained to locate the player region and trim the frames. Two time fusion methods over the frames wereproposed and evaluated with CNN models which were created based on the ResNet models and a transfer learning approach was used to train them. The results show that these models were able of classifying the frames with their corresponding phase with an accuracy of 92.21% in our best model. Also it can be seen that the RGB merging method shown in this paper helps to slightly improve the performance of the models. Furthermore, the models were capable of learning the temporality of the phases as the mistakes done by the models occurred between consecutive phases. © 2020 ACM.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Production and Characterization of Extremophilic Proteinases From a New Enzyme Source, Barrientosiimonas sp. V9
No full textMicrobial proteases are widely used as commercial enzymes, which have an active role in several industrial processes. The aim of this study was to investigate the production and properties of extracellular proteases from Barrientosiimonas sp. strain V9. The cultivation conditions for protease production were studied using different carbon and nitrogen sources. Maximum protease production was obtained in medium containing 25 g L?1 sucrose, 7 g L?1 KNO3, and initial pH 7.0 at 35 °C and 150 rpm during 72 h. Under these conditions, maximum proteolytic activity reached 1200 U mL?1. The enzyme extract showed optimum activity at 60 °C, pH 9.0, and was stable from 30 to 50 °C within a pH range from 4.0 to 10.0 and NaCl concentration up to 2.5 M. The enzyme was stable in the presence of EDTA, urea, Triton X-100 and laundry detergent (sodium lauryl sulfate as main component). The addition of 1% sodium dodecyl sulfate, Tween-80, or Tween-20 increased the activity by 183% and 119% respectively, while 2-mercaptoethanol reduced the activity to 71%. Casein zymogram analysis revealed three hydrolysis zones suggesting that Barrientosiimonas sp. V9 expresses proteases with molecular weights about 60, 45, and 35 kDa, which were inhibited in the presence of phenylmethylsulfonyl fluoride. Barrientosiimonas sp. V9 produces halotolerant serine proteases with great biotechnological potential. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Integrated microfluidic preconcentration and nucleic amplification system for detection of influenza a virus H1N1 in saliva
No full textInfluenzaAviruses are often present in environmental and clinical samples at concentrations below the limit of detection (LOD) of molecular diagnostics. Here we report an integrated microfluidic preconcentration and nucleic amplification system (?FPNAS) which enables both preconcentration of influenza A virus H1N1 (H1N1) and amplification of its viral RNA, thereby lowering LOD for H1N1. H1N1 virus particles were first magnetically preconcentrated using magnetic nanoparticles conjugated with an antibody specific for the virus. Their isolated RNA was amplified to cDNA through thermocycling in a trapezoidal chamber of the ?FPNAS. A detection limit as low as 100 TCID50 (50% tissue culture infective dose) in saliva can be obtained within 2 hours. These results suggest that the LOD of molecular diagnostics for virus can be lowered by systematically combining immunomagnetic separation and reverse transcriptase-polymerase chain reaction (RT-PCR) in one microfluidic device. © 2020 by the authors.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Evaluation of an integrated wood-burning stove with water tank system for heating rural homes in the Andean highlands of Peru
No full textIn this work, we study an improved wood-burning stove with a water tank placed in the flue gas outlet for use as a heater. This system takes advantage of the waste heat of the gases that pass through the chimney to heat the water contained in the tank. The evaluations were carried out in a house located in the district of San Antonio de Chuca (Imata), province of Caylloma, department of Arequipa, Peru, located above 4500m above sea level, where temperatures decrease to -20 °C during winter. A method is proposed to measure the power input of the integrated tank, which consists of finding the maximum power that the flue gas delivers to the water in the tank when the stove is turned on. Once this power has been identified, the wood-burning stove is replaced by an electric heating system that delivers the same power to heat the water. Once the electrical system has been calibrated, the water in the tank is heated to different temperatures, and the following are calculated: the accumulated energy, the time needed to reach the desired temperature and the amount of wood that would be used if the kitchen were used for heating. The power that the heater can deliver to the test house is thus determined. If the water in the tank is heated to 70 °C, this heating system can deliver an average power value of 450 W from 20:00 to 5:00 the next day. © Published under licence by IOP Publishing Ltd.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Spanish Sentiment Analysis Using Universal Language Model Fine-Tuning: A Detailed Case of Study
No full textTransfer Learning has emerged as one of the main image classification techniques for reusing architectures and weights trained on big datasets so as to improve small and specific classification tasks. In Natural Language Processing, a similar effect is obtained by reusing and transferring a language model. In particular, the Universal Language Fine-Tuning (ULMFiT) algorithm has proven to have an impressive performance on several English text classification tasks. In this paper, we aim at improving current state-of-the-art algorithms for Spanish Sentiment Analysis of short texts. In order to do so, we have adapted a ULMFiT algorithm to this setting. Experimental results on benchmark datasets show the potential of our approach. © Springer Nature Switzerland AG 2020.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte