1
artículo
Publicado 2020
Enlace
Enlace
Vegetables foods are contaminated with heavy metals by different routes, being a risk to the health of the consumer. In this study was performed the quantification of heavy metals cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) in fresh tubers of three potato varieties of Solanum tuberosum L. (potato): canchan, huayro and yellow. The samples were randomly collected from 15 stalls in the wholesale market of Santa Anita, province of Lima (Lima - Peru) all from the province of Ambo, department of Huánuco (Peru); 15 samples were collected from each variety with a total of 45 samples. The quantification of Cd and Pb was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), meanwhile, for the quantification of Hg and As, was used Atomic Fluorescence Spectrometry (AFS).. The Hg concentration ranged from 0,0983 to 0,2594 mg / Kg; Cd from 0,0073 to 0,0287 mg / Kg; Pb from 0,...
2
artículo
Publicado 2020
Enlace
Enlace
Vegetables foods are contaminated with heavy metals by different routes, being a risk to the health of the consumer. In this study was performed the quantification of heavy metals cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) in fresh tubers of three potato varieties of Solanum tuberosum L. (potato): canchan, huayro and yellow. The samples were randomly collected from 15 stalls in the wholesale market of Santa Anita, province of Lima (Lima - Peru) all from the province of Ambo, department of Huánuco (Peru); 15 samples were collected from each variety with a total of 45 samples. The quantification of Cd and Pb was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), meanwhile, for the quantification of Hg and As, was used Atomic Fluorescence Spectrometry (AFS).. The Hg concentration ranged from 0,0983 to 0,2594 mg / Kg; Cd from 0,0073 to 0,0287 mg / Kg; Pb from 0,...
3
artículo
La carragenina se utilizó para preparar películas de carragenina reforzadas con nanobigotes de quitina. Se utilizó microscopia de fuerza atómica para caracterizar la morfología y rugosidad de las películas. La caracterización estructural se realizó mediante difracción de rayos X y espectroscopia infrarroja de transformada de Fourier. Las propiedades mecánicas se evaluaron mediante ensayos de tracción. Los nanocompuestos preparados se utilizaron como sustrato celular para explorar sus posibles aplicaciones biológicas. Se sembraron células HeLa en las muestras para evaluar su biocompatibilidad. Los resultados preliminares muestran buena proliferación celular pero baja adhesión celular, demostrando una posible aplicación de este nuevo material como sustrato para el cultivo de células tumorales.
4
artículo
Publicado 2017
Enlace
Enlace
A novel method to prepare BC nanocomposites reinforced with reduced graphene oxide (RGO) is reported. A simple hydrazine treatment is shown to in-situ reduce the graphene oxide (GO) incorporated to BC films while increasing their conductivity. Raman spectroscopy was used to confirm the presence of graphene and assess the effect of the hydrazine treatment on its structure. XRD tests revealed no changes on BC structure. We hypothesize that this treatment removes the hydroxyl and epoxy groups present on the reduced graphene and increases the content of nonoxygenated carbon. These changes account for the increase in conductivity of the BC-based films, which behaved as an insulating material before the hydrazine treatment and reach an average conductivity value of 12 S/m after such a treatment.
5
artículo
The authors would like to thank the Direction of Research (DAI) of PUCP, the Science and Technology Council of Peru (CONCYTEC), the Spanish Research Council (CSIC) and the Generalitat Valenciana, Conselleria de Empresa, Universidad y Ciencia (project number ARVIV/2007/101) for financial support.
6
artículo
Publicado 2019
Enlace
Enlace
In this study, we analyzed the contribution of NH4I and glycerol on the ionic conductivity of carboxymethyl κ/ι-hybrid carrageenan-based solid bio-electrolytes. Electrochemical impedance spectroscopy was used to assess the electrochemical properties of the developed biopolymeric films and their interfaces over a wide range of frequencies (1& Hz–7& MHz). X-ray diffractograms demonstrated the increment of the amorphous fraction in the material as the NH4I content increases, suggesting an enhancement of ion transport processes and the successful incorporation of the salt into the host matrix. The shift of the OH peaks in the FTIR spectra confirmed the interaction between carboxymethyl carrageenan, NH4I, and glycerol. EIS results were represented in the complex plane and were fitted to an Rs(R1Q1) equivalent circuit. The ionic conductivity for carboxymethyl carrageenan doped with xNH4I (...
7
artículo
Publicado 2019
Enlace
Enlace
In this study, we analyzed the contribution of NH4I and glycerol on the ionic conductivity of carboxymethyl κ/ι-hybrid carrageenan-based solid bio-electrolytes. Electrochemical impedance spectroscopy was used to assess the electrochemical properties of the developed biopolymeric films and their interfaces over a wide range of frequencies (1& Hz–7& MHz). X-ray diffractograms demonstrated the increment of the amorphous fraction in the material as the NH4I content increases, suggesting an enhancement of ion transport processes and the successful incorporation of the salt into the host matrix.
8
artículo
Publicado 2019
Enlace
Enlace
This work was supported by the Vice-Rectorate for Research of the Pontificia Universidad Católica del Perú, the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT) and The National Innovation Program for Competitiveness and Productivity (INNOVATE-PERU) of the Peruvian Ministry of Production.
9
artículo
Publicado 2019
Enlace
Enlace
The effect of carboxymethylation and NH4I incorporation on the molecular dynamics of carrageenan films was studied. Broadband Dielectric Spectroscopy (BDS) assessed the presence of α and β relaxation processes. The effect of NH4I content was analyzed using the Havriliak-Negami model and parameterizing the temperature dependence of the relaxation times according to the Vogel-Fulcher-Tammann-Hesse (VFTH) equation. The glass transition temperature was found to decrease with the increase of NH4I content. These results suggest that carboxymethylation and the salt doping treatment increase the molecular mobility of NH4+ ions, making the films suitable for the development of solid electrolytes for energy storage applications. © 2018, © 2018 Taylor & Francis Group, LLC.
10
artículo
The authors would like to thank the vice-rectorate for research of the Pontificia Universidad Católica del Perú and the Peruvian Council of Science and Technology (Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica–Fondo Nacional de Desarrollo Científico y Tecnológico) for financial support. Dr Vicente Lorenzo from the Polytechnical University of Madrid is acknowledged for providing technical support during the microhardness tests.
11
artículo
Publicado 2020
Enlace
Enlace
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the National Council of Science, Technology and Technological Innovation [CONCYTEC-FONDECYT]; and the Vice-Rectorate for Research of the Pontificia Universidad Catolica del Peru [VRI-PUCP].
12
artículo
Publicado 2018
Enlace
Enlace
Se utilizaron exopolisacáridos (EPS) extraídos de cianobacterias de Nostoc commune para preparar sustratos celulares de baja adhesión para el crecimiento de células selectivas tumorales. Los sustratos fueron reforzados con bigotes de quitina y nanopartículas de almidón y caracterizados mediante espectroscopia infrarroja Fouriertransform, difracción de rayos X y pruebas de tracción. Se sembraron dos células independientes de anclaje, HeLa modificada por GFP y células THP-1 en las muestras para evaluar su interacción con los compuestos. Los resultados confirmaron la interacción de la superficie celular de los compuestos a base de EPS. Las propiedades mecánicas de estas películas se pueden adaptar controlando el tipo y la concentración del refuerzo, que se puede utilizar en el diseño de diferentes tipos de biomateriales.
13
artículo
Publicado 2021
Enlace
Enlace
The Vice-Rectorate for Research (VRI-PUCP) of the Pontificia Universidad Catolica del Peru and the National Council of Science, Technology and Technological Innovation (CONCYTEC-FONDECYT) are greatly acknowledged for financial support. The Institute of Polymer Science and Technology of the Spanish Council for Scientific Research (ICTP-CSIC, Madrid, Spain) is acknowledged for experimental assistance.
14
artículo
Publicado 2021
Enlace
Enlace
Purpose: The COVID-19 pandemic is a colossal challenge for global health; nonetheless, specific subgroups face considerably higher risks for infection and mortality. Among patients with malignant diseases, those with hematologic neoplasms are at a higher risk for poor outcomes. The objective of this study was to register treatment modifications associated with the COVID-19 pandemic and their short-term consequences in Latin America.Methods: Multicenter, prospective, observational, cohort study including patients older than 14 years from 14 centers in four countries (Mexico, Peru, Guatemala, and Panama) who had a confirmed diagnosis of acute leukemia, and who were undergoing active treatment since the first COVID-19 case in each country until the cutoff on July 15, 2020.Results: We recruited 635 patients. Treatment modifications because of the COVID-19 pandemic were reported in 40.8% of c...
15
artículo
Publicado 2021
Enlace
Enlace
Purpose: The COVID-19 pandemic is a colossal challenge for global health; nonetheless, specific subgroups face considerably higher risks for infection and mortality. Among patients with malignant diseases, those with hematologic neoplasms are at a higher risk for poor outcomes. The objective of this study was to register treatment modifications associated with the COVID-19 pandemic and their short-term consequences in Latin America. Methods: Multicenter, prospective, observational, cohort study including patients older than 14 years from 14 centers in four countries (Mexico, Peru, Guatemala, and Panama) who had a confirmed diagnosis of acute leukemia, and who were undergoing active treatment since the first COVID-19 case in each country until the cutoff on July 15, 2020. Results: We recruited 635 patients. Treatment modifications because of the COVID-19 pandemic were reported in 40.8% of...
