Álvaro Terán-Alcocer, Francisco Bravo-Plascencia, Carlos Cevallos-Morillo, Alex Palma‐Cando,
Electrochemical sensors appear as low-cost, rapid, easy to use, and in situ devices for determination of diverse analytes in a liquid solution. In that context, conducting polymers are much-explored sensor building materials because of their semiconductivity, structural versatility, multiple synthetic pathways, and stability in environmental conditions. In this state-of-the-art review, synthetic processes, morphological characterization, and nanostructure formation are analyzed for relevant literature ...
Tópico(s): Electrochemical Analysis and Applications
2021 - Multidisciplinary Digital Publishing Institute | Nanomaterials
Francisco Montenegro, Luis Unigarro, Gustavo Reaño Paredes, Tatiana Moya, Ana Belén Serrano Romero, Liliana Torres, Juan Carlos López‐Azor, Fernando Esteban Jara González, Gustavo Pozo, Andrés López‐Cortés, Ana María Diaz, Eduardo Vásconez, Doménica Cevallos-Robalino, Alex Lister, Esteban Ortiz‐Prado,
Introduction The exponential growth of SARS-CoV-2 virus transmission during the first months of 2020 has placed substantial pressure on most health systems around the world. The complications derived from the novel coronavirus disease (COVID-19) vary due to comorbidities, sex and age, with more than 50% of the patients requiring some level of intensive care developing acute respiratory distress syndrome (ARDS). The authors carried out an extensive and comprehensive literature review on SARS-CoV-2 ...
Tópico(s): Intensive Care Unit Cognitive Disorders
2020 - Taylor & Francis | Expert Review of Respiratory Medicine
M. B. Sanders, F. Alex Cevallos, R. J. Cava,
We report the magnetic properties of compounds in the KBaRE(BO3)2 family (RE = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb), materials with a planar triangular lattice composed of rare earth ions. The samples were analyzed by x-ray diffraction and crystallize in the space group R-3m. Physical property measurements indicate the compounds display predominantly antiferromagnetic interactions between spins without any signs of magnetic ordering above 1.8 K. The ideal 2D rare earth triangular layers in this structure ...
Tópico(s): Multiferroics and related materials
2017 - IOP Publishing | Materials Research Express
Wudi Wang, Stephan Kim, Minhao Liu, F. Alex Cevallos, R. J. Cava, N. P. Ong,
Edge supercurrents in superconductors have long been an elusive target. Interest in them has reappeared in the context of topological superconductivity. We report evidence for the existence of a robust edge supercurrent in the Weyl superconductor molybdenum ditelluride (MoTe2). In a magnetic field B, fluxoid quantization generates a periodic modulation of the edge condensate observable as a "fast-mode" oscillation of the critical current Ic versus B The fast-mode frequency is distinct from the conventional ...
Tópico(s): Graphene research and applications
2020 - American Association for the Advancement of Science | Science
Shu Guo, Tai Kong, Weiwei Xie, Loi T. Nguyen, Karoline Stolze, F. Alex Cevallos, R. J. Cava,
A previously unreported family of electrically insulating rare-earth borates, RbBaR(BO3)2 (R = Y, Gd–Yb), was designed and then successfully obtained by traditional solid-state reaction. They crystallize in a monoclinic crystal system space group P21/m (No. 11). They feature triangular planar rare-earth (R) lattices, which are part of, for example, [Yb(BO3)2]3– infinite 2D layers. These R-based triangular lattices are stacked with layers of crystallographically ordered Rb and Ba atoms to build the 3D ...
Tópico(s): Iron-based superconductors research
2019 - American Chemical Society | Inorganic Chemistry
F. Alex Cevallos, Shu Guo, Hoseok Heo, Giovanni Scuri, You Zhou, Jiho Sung, Takashi Taniguchi, Kenji Watanabe, Philip Kim, Hongkun Park, R. J. Cava,
The growth of single crystals of MoS2 and WS2 by materials transport through a liquid salt flux made from a low-melting mixture of NaCl and CsCl is presented. The crystals are structurally characterized by single-crystal X-ray diffraction, which reveals that the 2H-MoS2 crystals contain a very small percentage (about 3%) of 3R intergrowths and that the 2H-WS2 crystals display less than 1% of 3R intergrowths. Characterization of the crystals by scanning electron microscopy is presented as are photoluminescence ...
Tópico(s): Chalcogenide Semiconductor Thin Films
2019 - American Chemical Society | Crystal Growth & Design
Karoline Stolze, F. Alex Cevallos, Tai Kong, R. J. Cava,
Previously unreported High-Entropy Alloy (HEA) superconductors in the pentanary (ZrNb) 1−x [MoReRu] x , (HfTaWIr) 1−x [Re] x , and (HfTaWPt) 1−x [Re] x systems are described and characterized.
Tópico(s): Advanced materials and composites
2018 - Royal Society of Chemistry | Journal of Materials Chemistry C
F. Alex Cevallos, Karoline Stolze, Tai Kong, R. J. Cava,
The crystal growth, structure, and basic magnetic properties of TmMgGaO4 are reported. The Tm ions are located in a planar triangular lattice consisting of distorted TmO6 octahedra, while the Mg and Ga atoms randomly occupy intermediary bilayers of M-O triangular bipyramids. The Tm ions are positionally disordered. The material displays an antiferromagnetic Curie Weiss theta of ∼−20 −25 K, with no clear ordering visible in the magnetic susceptibility down to 1.8 K; the structure and magnetic properties ...
Tópico(s): Magnetic and transport properties of perovskites and related materials
2018 - Elsevier BV | Materials Research Bulletin
Shu Guo, Tai Kong, F. Alex Cevallos, Karoline Stolze, R. J. Cava,
Crystals of the KBaR(BO3)2 (R = Y, Gd, Tb, Dy, Ho, Tm, Yb and Lu) rare earth borates were grown by spontaneous nucleation from a KF-B2O3 flux. The crystals obtained were typically well-developed hexagonal plates about 1 mm in large dimension. The crystals were used to study the anisotropic temperature and field dependent magnetization of the materials, which are based on ideal triangular planes of magnetic rare earths. All structures were refined in space group R3-m by single-crystal X-ray diffraction, ...
Tópico(s): High-pressure geophysics and materials
2018 - Elsevier BV | Journal of Magnetism and Magnetic Materials
F. Alex Cevallos, Karoline Stolze, R. J. Cava,
The single crystal growth, structure, and basic magnetic properties of ErMgGaO4 are reported. The structure consists of triangular layers of magnetic ErO6 octahedra separated by a double layer of randomly occupied non-magnetic (Ga,Mg)O5 bipyramids. The Er atoms are positionally disordered. Magnetic measurements parallel and perpendicular to the c axis of a single crystal reveal dominantly antiferromagnetic interactions, with a small degree of magnetic anisotropy. A weighted average of the directional ...
Tópico(s): Multiferroics and related materials
2018 - Elsevier BV | Solid State Communications
Stefano Buitrón Cevallos, Alex X. Jerves, Utkarsh Mital, David Medina, V. Santiago Quinteros, Maurizio Mulas, Øyvind Torgersrud,
We introduce a Convolutional Neural Network (CNN) to reduce grains' manual inspection time after image processing on raw 3D x-ray computed tomography (3DXRCT) images from a sample of granular material to obtain level-set function-based digital twins of individual grains. The CNN automatically distinguishes properly segmented digital grains with up to 90% of accuracy. This algorithm is trained using, ground-truth, level set-based digital grain representations from a natural soil sampled at Jaramijó ( ...
Tópico(s): Drilling and Well Engineering
2023 - Elsevier BV | Computers and Geotechnics
Esteban Ortiz‐Prado, Katherine Simbaña‐Rivera, Gabriel Cevallos, Lenin Gómez‐Barreno, Domenica Cevallos, Alex Lister, Raúl Fernández-Naranjo, Blanca Ríos‐Touma, Eduardo Vásconez, Juan S. Izquierdo‐Condoy,
Background Despite worldwide progress in terms of clean water supply, sanitation, and hygiene knowledge, some middle and most of low-income countries are still experiencing many diseases transmitted using unsafe water and the lack of sanitation. Methods To understand the impact of all waterborne diseases (WBD) registered in Ecuador. We performed a population-based analysis of all cases and deaths due to WBD in Ecuador based on the national public databases of hospital discharges as a proxy of incidence, ...
Tópico(s): Global Maternal and Child Health
2022 - Frontiers Media | Frontiers in Public Health
Yesenia Cevallos, Lorena Molina, Alex Santillán, Floriano De Rango, Ahmad Rushdi, Jesús B. Alonso,
Tópico(s): Gene expression and cancer classification
2016 - Springer Science+Business Media | Cognitive Computation
F. Alex Cevallos, Shu Guo, R. J. Cava,
The synthesis, structural description, temperature dependent magnetic susceptibilities and field dependent magnetizations of a series of rare earth garnets of the form Li3RE3Te2O12 (RE = Y, La, Pr, Nd, Sm-Lu) are reported. The structure of Li3Dy3Te2O12 is refined from powder x-ray diffraction data. The field dependent magnetizations saturate for some of the members by 9 Tesla at 2 K. Of particular interest for further study in this family is the behavior of the Pr, Tb, Dy and Yb garnets.
Tópico(s): Multiferroics and related materials
2018 - IOP Publishing | Materials Research Express
Óscar Arteaga, Alex Cevallos, María I. Erazo, Klever D. Morales, Daniel B. Tenezaca, Edison Argüello M.,
The article is about of research of the behavior of magnetorheological materials (MR), later it will be implemented in a prototype leg prosthesis with active damping for people who have suffered amputations in lower extremities, which considers the use of an actuator with Magnetorheological Fluids (MRF) LORD MRF – 140 CG, whose control is based on the adjustment of the magnetic field applied to the MRF using in its design the main parameters of anatomy and biomechanics of the foot-leg system, so that ...
Tópico(s): Diabetic Foot Ulcer Assessment and Management
2018 - EDP Sciences | MATEC Web of Conferences
Danrui Ni, Shu Guo, Zoë S. Yang, Hsin‐Ya Kuo, F. Alex Cevallos, R. J. Cava,
Tópico(s): Crystal Structures and Properties
2018 - Elsevier BV | Solid State Sciences
Esteban Ortiz‐Prado, Gabriel Cevallos-Sierra, Eduardo Vásconez, Alex Lister, Eduardo Pichilingue Ramos,
Isolated Indigenous peoples are a group of Indigenous tribes that live in voluntary isolation in remote and mostly inaccessible territories. Together with Indigenous peoples in initial contact, Isolated Indigenous peoples are threatened continuously by advancing extractive activities, the absence of public policies and protection measures by the State, and the pressure of illegal activities on their territories. Generating multidimensional public policies that protect these groups is essential. ...
Tópico(s): Mining and Resource Management
2021 - SAGE Publishing | AlterNative An International Journal of Indigenous Peoples
David Sebastian Puma-Benavides, Aléx Santiago Cevallos Carvajal, Ángel Guillermo Masaquiza Yanzapanta, Milton I. Quinga-Morales, Rodrigo Rigoberto Moreno-Pallares, Henrry Gabriel Usca-Gomez, Fernando Alejandro Murillo,
This analysis compares the energy efficiency and operational costs of combustion vehicles (Hyundai Accent 1.6 L and Chevrolet Sail 1.5 L) with the Nissan Leaf, an electric vehicle, under current fuel and electricity pricing in Ecuador. Combustion vehicles, converting gasoline into mechanical energy, demonstrate substantial energy losses, leading to higher operational costs, especially with recent gasoline price hikes to USD 2.722 per gallon. In stark contrast, the Nissan Leaf exhibits significantly ...
Tópico(s): Advanced Combustion Engine Technologies
2024 - Multidisciplinary Digital Publishing Institute | World Electric Vehicle Journal
Alex Cevallos-Culqui, Clàudia Pons, Gustavo Rodríguez,
The continuous increase of digital documents on the web creates the need to search for information patterns that allow the categorization of organizational documents to generate knowledge in an institution. An Artificial Intelligence technique for this purpose is text classification, it for its application uses labels (previously categorized documents) with supervised (with labels) or unsupervised (without labels) training models. Both traditional models with their advantages and disadvantages have ...
Tópico(s): Organizational and Employee Performance
2023 - Asociación Española para la Inteligencia Artificial | INTELIGENCIA ARTIFICIAL
Danrui Ni, Shu Guo, Kelly M. Powderly, Ruidan Zhong, Jingjing Lin, Tai Kong, F. Alex Cevallos, R. J. Cava,
Tópico(s): Advanced Thermoelectric Materials and Devices
2018 - Elsevier BV | Journal of Solid State Chemistry
R. Simón Carballo, G. Rodrı́guez-Fuentes, Cevallos Urbina, Alex Coene Fleitas,
This chapter discusses the study of the reaction of calcium (Ca)-clinoptilolite and human bile. The Ca exchanged form of the purified natural clinoptilolite (NZ) from the Tasajeras deposit, Cuba, is the active ingredient of a drug designed to reduce total blood cholesterol and prevent atherosclerosis. The study of the Ca2+-NZ-human bile reaction reveals that it occurs through the adsorption of three major human bile compounds—namely, bile acids, phospholipids, and bilirubin. The adsorption of phospholipids ...
Tópico(s): Metabolism and Genetic Disorders
2001 - Elsevier BV | Studies in surface science and catalysis
Santiago Maffia‐Bizzozero, Cintia Cevallos, Federico Remes Lenicov, Rosa Nicole Freiberger, Cinthya Alicia Marcela López, Alex David Guano Toaquiza, Franco Agustín Sviercz, Patricio Jarmoluk, Cristina A. Bustos, Adriana C. D’Addario, Jorge Quarleri, M. Victoria Delpino,
Pulmonary and extrapulmonary manifestations have been described after infection with SARS-CoV-2, the causative agent of coronavirus disease 2019 (COVID-19). The virus is known to persist in multiple organs due to its tropism for several tissues. However, previous reports were unable to provide definitive information about whether the virus is viable and transmissible. It has been hypothesized that the persisting reservoirs of SARS-CoV-2 in tissues could be one of the multiple potentially overlapping ...
Tópico(s): SARS-CoV-2 detection and testing
2023 - Frontiers Media | Frontiers in Microbiology
Esteban Ortiz‐Prado, Martha Fors, Aquiles R. Henríquez-Trujillo, Gabriel Cevallos-Sierra, Alejandra Barreto, Katherine Simbaña‐Rivera, Lenin Gómez‐Barreno, Eduardo Vásconez, Alex Lister,
Health systems worldwide rely on health professionals to deliver services and provide framework structures. Considering their opinions about their work environment, the public policies that regulate their work and the deficiencies of the health care system are key aspects of the governance within the system. The aim of this study was to assess the perceptions of Ecuadorian physicians about several aspects of the performance of the health delivery and monitoring systems locally.A cross-sectional ...
Tópico(s): Healthcare Policy and Management
2019 - BioMed Central | BMC Health Services Research
Katherine Simbaña‐Rivera, Pablo R. Morocho Jaramillo, Javier V. Velastegui Silva, Lenin Gómez‐Barreno, Ana B. Ventimilla Campoverde, Juan F. Novillo Cevallos, Washington E. Almache Guanoquiza, Silvio L. Cedeño Guevara, Luis Gonzalez Castro, Nelson A. Moran Puerta, Alex W. Guayta Valladares, Alex Lister, Esteban Ortíz-Prado,
Background Multiple studies have attempted to elucidate the relationship between chronic hypoxia and SARS-CoV-2 infection. It seems that high-altitude is associated with lower COVID-19 related mortality and incidence rates; nevertheless, all the data came from observational studies, being this the first one looking into prospectively collected clinical data from severely ill patients residing at two significantly different altitudes. Methods A prospective cohort, a two-center study among COVID-19 ...
Tópico(s): Heme Oxygenase-1 and Carbon Monoxide
2022 - Public Library of Science | PLoS ONE
Carlos Cevallos-Morillo, Pablo A. Cisneros–Pérez, Roxana Llive, Marvin Ricaurte, Carlos Reinoso, Miguel Ángel Meneses, Maria del Cisne Guamán, Alex Palma‐Cando,
Croton lechleri, commonly known as Dragon's blood, is a tree cultivated in the northwest Amazon rainforest of Ecuador and Peru. This tree produces a deep red latex which is composed of different natural products such as phenolic compounds, alkaloids, and others. The chemical structures of these natural products found in C. lechleri latex are promising corrosion inhibitors of admiralty brass (AB), due to the number of heteroatoms and π structures. In this work, three different extracts of C. lechleri ...
Tópico(s): Concrete and Cement Materials Research
2021 - Multidisciplinary Digital Publishing Institute | Molecules
Edwin Fabricio Morales Guerrero, Viviana Estefania Piedra Aguirre, Alex Paul Cevallos Pazmiño, Fernando Javier Mafla Camacho,
Los trastornos de la articulación de la cadera son comunes en la población pediátrica. Estos pacientes usualmente se presentan a los servicios de emergencias pediátricos o de atención primaria por motivos de consulta inespecíficos como coxalgia o cojera. Se dice que aproximadamente el 5% del total de las consultas realizadas en dichos centros corresponde a cojera de origen no traumático. Para llevar a cabo la revisión bibliográfica sobre el presente trabajo de investigación, se realizó una búsqueda ...
Tópico(s): Spondyloarthritis Studies and Treatments
2024 - | RECIMUNDO
Catherine Alexandra Rodríguez-Quishpe, Alex Santiago Cevallos-Carvajal, Christian Andrey Crespo-Ruiz, Kevin Alejandro Granizo-Cárdenas,
La industria automotriz es una de las más dinámicas del mundo, los autos son un elemento vital para el transporte en muchos sectores de la sociedad, desde el transporte individual hasta el transporte de diferentes productos y materiales, este tipo de vehículos por lo general usan combustibles fósiles, los cuales han generado una serie de problemas de tipo ambiental en todo el planeta, aunado al alto costo de este tipo de combustible que se ha tornado más y más alto al pasar del tiempo. Esta investigación ...
Tópico(s): Political Dynamics in Latin America
2024 - | MQRInvestigar
Alex Paul Cevallos Pazmiño, Shahab Sebastian Burbano Valdivieso, Karen Mishell Jaramillo Bravo, Paola Andrea Betancourth Luzón,
La sinovitis villonodular pigmentada (SVNP) es una afección poco común que se caracteriza por un crecimiento anormal del tejido sinovial, que es el tejido que recubre las articulaciones. Este crecimiento anormal produce un tejido de color marrón o amarillo debido a la presencia de hemosiderina, un pigmento derivado de la hemoglobina. Para llevar a cabo esta revisión bibliográfica, se realizó una búsqueda exhaustiva en bases de datos científicas como PubMed, Scopus y Cochrane Library, utilizando términos ...
Tópico(s): Nail Diseases and Treatments
2024 - | RECIAMUC
Mario Andrés Ordóñez Lino, Francisco Fernando Loor Cevallos, Alex Bolívar Salvatierra Espinoza,
Las investigaciones han demostrado que los neumáticos de caucho desechados contienen en su estructura, moléculas que no permiten la descomposición en condiciones ambientales normales. La opción que más se ha usado con los años para eliminar este tipo de desecho es la quema del caucho, que si bien incinerado desaparece físicamente, igual produce otro tipo de contaminación como la atmosférica. Se plantea realizar un análisis comparativo del comportamiento mecánico del hormigón tradicional vs el hormigón ...
Tópico(s): Concrete Corrosion and Durability
2019 - Technical University of Madrid | Anales de Edificación
Jorge Luis López, María E. Jerves Crespo, Amparo de la Paz Rodríguez Romero, Raúl Leonardo Almeida Cevallos, Alex David Revelo Villacrés,
INTRODUCCIÓN: La diastematomielia es una malformación raquimedular, un desdoblamiento sagital de la médula espinal, frecuentemente por debajo de la quinta vértebra dorsal; siendo una presentación rara de disrafismo espinal (menos del 3 %), más frecuente en el sexo femenino (3:1), se presenta entre los 10 y 76 años de edad. Puede ser asintomática y un descubrimiento incidental. Su diagnóstico es básicamente radiológico. CASO CLÍNICO: Paciente de sexo masculino de 20 años de edad, con cuadro de lumbalgia ...
Tópico(s): Spinal Cord Injury Research
2018 - | Revista Médica del Hospital José Carrasco Arteaga