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Item Significantly enhancement of sunlight photocatalytic performance of ZnO by doping with transition metal oxides(2021-12) Ramírez, Alfonso E.; Montero Muñoz, Marly; Lizbeth Lorena Lopez Parra; Ramos Ibarra, J. E.; Coaquira, José Antônio Huamaní; Heinrichs, Benoît; Carlos PAEZIn this study we report, the synthesis of ZnO and its doping with Transition Metal Oxides -TMO-, such as Cr2O3, MnO2, FeO, CoO, NiO, Cu2O and CuO. Various characterization techniques were employed to investigate the structural properties. The X-ray diffraction (XRD) data and Rietveld refinement confirmed the presence of TMO phases and that the ZnO structure was not affected by the doping with TMO which was corroborated using transmission Electron microscopy (TEM). Surface areas were low due to blockage of adsorption sites by particle aggregation. TMO doping concentration in the range of 3.7–5.1% was important to calculate the catalytic activity. The UV–Visible spectra showed the variation in the band gap of TMO/ZnO ranging from 3.45 to 2.46 eV. The surface catalyzed decomposition of H2O2 was used as the model reaction to examine the photocatalytic activity following the oxygen production and the systems were compared to bulk ZnO and commercial TiO2-degussa (Aeroxyde-P25). The results indicate that the introduction of TMO species increase significantly the photocatalytic activity. The sunlight photocatalytic performance in ZnO-doped was greater than bulk-ZnO and in the case of MnO2, CoO, Cu2O and CuO surpasses TiO2 (P25-Degussa). This report opens up a new pathway to the design of high-performance materials used in photocatalytic degradation under visible light irradiation.Item The Frontiers of Memory: Human Rights as Potential Limits to the Construction of Memory in Colombia’s Law on Victims(2022-09) Alija Fernández, Rosa Ana; Tarapués Sandino, Diego F.; Martínez, Elisenda CalvetIncreasing demands for the international recognition of a human right to memory tend to disregard the potential conflict between this right and other recognized human rights in transitional justice processes. Relying on the lessons learned from the Colombian Victims and Land Restitution Law, this article provides an overview of the rights (both of the victims themselves and of the perpetrators) that might collide with, and impose restrictions on, an eventual right to memory, while discussing the practical safeguards in the design and implementation of the policies of memory that are necessary to accommodate the rights in conflict.Item A depth-controlled and energy-efficient routing protocol for underwater wireless sensor networks(2022-09) Lilhore, Umesh Kumar; Khalaf, Osamah Ibrahim; Simaiya, Sarita; Tavera Romero, Carlos Andrés; Abdulsahib, Ghaida Muttashar; Poongodi M.; Kumar, DineshUnderwater wireless sensor network attracted massive attention from researchers. In underwater wireless sensor network, many sensor nodes are distributed at different depths in the sea. Due to its complex nature, updating their location or adding new devices is pretty challenging. Due to the constraints on energy storage of underwater wireless sensor network end devices and the complexity of repairing or recharging the device underwater, this is highly significant to strengthen the energy performance of underwater wireless sensor network. An imbalance in power consumption can cause poor performance and a limited network lifetime. To overcome these issues, we propose a depth controlled with energy-balanced routing protocol, which will be able to adjust the depth of lower energy nodes and be able to swap the lower energy nodes with higher energy nodes to ensure consistent energy utilization. The proposed energy-efficient routing protocol is based on an enhanced genetic algorithm and data fusion technique. In the proposed energy-efficient routing protocol, an existing genetic algorithm is enhanced by adding an encoding strategy, a crossover procedure, and an improved mutation operation that helps determine the nodes. The proposed model also utilized an enhanced back propagation neural network for data fusion operation, which is based on multi-hop system and also operates a highly optimized momentum technique, which helps to choose only optimum energy nodes and avoid duplicate selections that help to improve the overall energy and further reduce the quantity of data transmission. In the proposed energy-efficient routing protocol, an enhanced cluster head node is used to select a strategy that can analyze the remaining energy and directions of each participating node. In the simulation, the proposed model achieves 86.7% packet delivery ratio, 12.6% energy consumption, and 10.5% packet drop ratio over existing depth-based routing and energy-efficient depth-based routing methods for underwater wireless sensor network.Item Synthesis, Characterization and Structural Analysis of Two New Biguanide Complexes(2023-08) Pastrana Dávila, Andrea; Minotta, Gianella; Ellena, Javier; Santiago, Pedro H. O.; D’Vries, Richard F.This study reports on the synthesis and characterization of two new coordination compounds of the active pharmaceutical ingredient metformin and transition metals. The cobalt compound with the formula [Co(Met)3][CoCl4]Cl·3H2O is a complex salt formed by a cationic Co(III) octahedral and anionic Co(II) tetrahedral subunits. The Cu(II) complex is represented by the formula [(Cu(Met)Cl)2-μ-Cl2] and is a dimeric compound with two chloride anions acting as a bridge, forming shared-edge square pyramidal units. Both compounds were characterized by single crystal X-ray diffraction, FT-IR spectroscopy and thermal analysis.Item Antibacterial activity and molecular studies of non-symmetric POCOP-Pd(II) pincer complexes derived from 2,4-dihydroxybenzaldehyde (2,4-DHBA)(2022-11-15) Aragón Muriel, Alberto; Aguilar Castillo, Bethsy A.; Rufino Felipe, Ernesto; Valdés, Hugo; González Sebastián, Lucero; Osorio Yáñez, Rebeca Nayely; Liscano, Yamil; Gómez Benítez, Valente; Polo Cerón, Dorian; Morales Morales, DavidA series of non-symmetric POCOP-Pd(II) pincer complexes including an aldehyde group in the meta-position of the aromatic pincer-backbone were prepared and characterized. The molecular structure of complex 1-Pd was unambiguously determined by single crystal X-ray diffraction analysis, showing a square-planar geometry around the metal fragment and the presence of the aldehyde functionality at the pincer ligand backbone. The evaluation of the antibacterial activities of complexes 2-Pd and 3-Pd against gram-positive and gram-negative strains was performed. Complex 3-Pd was the most active against S. aureus ATCC 25923 strain with a MIC value of 8 µg∙mL−1. We also determined by molecular docking studies, that pincer complexes 2-Pd and 3-Pd may interact with some key bacterial enzymes such as KPC-2 and PBP2A.Item Las Tecnologías de la información para el bienestar estudiantil durante y después de la pandemia en instituciones de enseñanza superior(2024-03-15) Benavides Meza, Yasmín Liliana; Avendaño Rodríguez, Luis Alfredo; Giraldo Arias, LauraObjective. Recognize, identify and analyze the strategies and activities implemented by the University under study and other universities in Colombia, focusing on the use of information and communications technologies (ICT) for student well-being before, during and after the pandemic. Methodology. The research will be developed from a qualitative approach, since it focuses on the systematic search for relevant information in academic and local databases. It focuses on identifying and reviewing the existing literature on the topic of interest, with the aim of obtaining a deep understanding of the various perspectives and findings related to student well-being and the use of interactive tools in the university context before, during and after the pandemic.Item El uso de las TIC para el bienestar estudiantil antes, durante y después de la pandemia en IES en Colombia que han trabajado sobre este aspecto(2024-06-12) Benavides Meza, Yasmin Liliana; Avendaño Rodríguez, Luis Alfredo; Giraldo Arias, LauraReconocer, identificar y analizar las estrategias y actividades implementadas por la Universidad objeto de estudio y otras universidades de Colombia, enfocándose en el uso de herramientas interactivas para el bienestar estudiantil antes, durante y después de la pandemiaItem Inverse heat transfer problem for the characterization of nanofluids produced with different types of palladium nanoparticles(2024) Silva, Nilton P.; Varon, Leonardo A.B.; Cruz, Cláudia C.R.; Fonseca, Henrique M.; Costa, Jose M.J.; Cesar, Claudio L.; Santos, Dilson S. Dos; Orlande, Helcio R.B.The objective of this work is the measurement of physical properties of distilled water nanofluids containing palladium nanocubes, palladium cerium oxide nanoparticles, and their respective hydrides. Due to their biocompatibility and favorable photothermal effects, palladium nanoparticles can be used to promote localized absorption of external energy sources in the thermal treatment of cancer, aiming at a thermal damage constrained to the tumor region without significant effects to the healthy tissues. An inverse problem is solved here within the Bayesian framework of statistics with the Markov Chain Monte Carlo method, by using nonintrusive transient measurements taken with an infrared camera during the heating of different water-based nanofluids. The mathematical model used in this work takes into account natural convection effects, due to the nonuniform heat source caused by the diode-laser that heats the nanofluids. Prior distributions for the model parameters were selected based on additional independent measurements, theoretical models and by the careful implementation of the experiments. The proposed model and the estimated parameters were validated, with an excellent agreement between the measured temperatures and those obtained from stochastic simulations during the solution of the inverse problem.Item El campo de la transposición didáctica en la transición de la aritmética al álgebra: Una revisión sistemática(2024-06-13) Garcia Fajardo, Victoria Alejandra; Burbano González, Diana CarolinaRealizar una revisión sistemática con el propósito de conocer las tendencias con relación a los procesos de enseñanza y de aprendizaje en la transición de la aritmética al álgebra a la luz de la transposición didáctica en instituciones de básica y media. To conduct a systematic review to identify trends related to teaching and learning processes in the transition from arithmetic to algebra in light of didactic transposition in basic and secondary education institutions.Item Phenomenological approach to the side effects of medicines in swallowing in the elderly population(Venezuelan Society of Pharmacology and Clinical and Therapeutic Pharmacology, 2020-07-07) Perdomo Galindo, Mónica Yohana; Ordóñez, Edward Javier; Luna Nieto, AlexanderBackground and Objective: A review of clinical histories is carried out in a population of 39 older women who are institutionalized in a geriatric and nursing home hospital in Colombia, recording the basic diagnosis and the medications they are given, in order to identify how the side effects of these medications interfere with one or more of the swallowing stages and what risk factors they may trigger for food intake. Materials and methods: In this study we used a descriptive exploratory method and a hermeneutic interpretation framework, based on swallowing screening, in the study population. Results: Given the basic pathology or pathologies presented by this population, they have pre-registration of various medications, which generate side effects that affect food intake, among which are: Xerostomia, alteration of intraoral sensitivity, motor alteration of the structures involved in swallowing, among others, affecting the dynamics of swallowing and safe food intake. Analysis: We identify the drugs that are being given to each patient, making a characterization and identification of side effects and how they can interfere in any of the phases of the swallowing, as well as risk factors arising from the alterations in any of the phases of the swallowing. The above is related to the fact that the main objective of the diet is to nourish and hydrate and any alteration in this process affects the quality of life of the elderly, even putting their lives at risk.Item Enhancing the production of the fermentable sugars from sugarcane straw: A new approach to applying alkaline and ozonolysis pretreatments(Elsevier Ltd, 2020-09-21) Orduña Ortega, Julieth; Mora Vargas, Jorge Andrés; Metzker, Gustavo; Gomes, Eleni De Barros; Da Silva, Roberto; Boscolo, MaurícioThe present study, sugarcane straw residue (SCS) was submitted to a combination of mild alkaline pretreatment and ozone cycles in a rotary reactor aiming to obtain fermentable sugars. The SCS exposed to short ozone cycles and short reaction times proved to be as efficient as long ozone exposure times usually employed, with no significant variation on the concentration of the fermentable sugars. Also, studies carried out on the ozone concentration, ozone exposure time, reaction time and biomass amount on the ozonolysis process were conducted. The washing processes after alkaline pretreatment and ozonolysis were also studied. During the alkaline pretreatment, approximately 73% of total phenolic compounds (TPC) was generated. After the first wash 79% of the TPC was washed away and 95% was removed after the second wash. The TPC content in wash solution obtained after ozonolysis is about 2.3% of the TPC generated with the alkaline pretreatment. For the enzymatic hydrolysate 0.20 g L−1 of TPC was obtained, a low value compared to similar studies. The inhibitor detected in the highest concentration was acetic acid for all solutions, except for ozonolysis where fumaric acid predominated. Hydroxymethylfurfural (HMF) and furfural were detected in amounts of less than 10 mg L−1.Item Characterization of people with type ii diabetes using electrical bioimpedance(Springer, 2020-08-11) Rodríguez Timaná, Luis Carlos; Castillo García, Javier FerneyDiabetes is a disease that causes the death of a person every seven seconds around the world and is also expensive. In 2014, it invested 600 billion dollars to be treated worldwide, that is why the need arises develop technological projects that allow the analysis of specific patterns in people suffering from this disease, in order to detect the pathology in a non-invasive manner and reduce costs, for which an electrical bioelectrical impedance analyzer was developed for the analysis of diabetes. The integrated AD5933 was used as a bioimpedance signal acquisition device and a beaglebone black development platform to process said data. Bioelectrical impedance data were taken from 5 healthy people and 3 people with the pathology. The data were processed by mathematical methods such as linearization with least squares and correlation, which allowed us to find parameters to differentiate between the signals of people with diabetes and people without diabetes. It was determined that people with diabetes have a curve that relates their bioimpedance in a range of frequencies from 10 kHz to 80 kHz, a curve that presented a high correlation to a power function of the form aXb. It was observed that the people who presented values of coefficients (a) greater than 38000 and exponents (b) less than −0.659 were people with diabetes, this in turn allowed to find the equation of a line that separates the two populations W0 + 1W * a + W2 * b = 0.Item System for analysis of human gait using inertial sensors(Springer, 2020-08-11) Saavedra Lozano, Diego Fernando; Castillo García, Javier FerneyGait laboratories using image processing are the standardized method to analyze human gait, but these are expensive, require restrictive workspaces, and post-processing times. On the other hand, inertial sensors are cheaper and reach high performance with lower computational cost in its implementation. In this work, a wireless system was implemented for the analysis of human gait using inertial sensors. The inertial sensor was chosen according to its specifications, cost, and pursuant to the characteristics of the human gait. In total, seven inertial sensors were used, arranged on the pelvis, thighs, legs and feet. A calibration algorithm was implemented to adjust the sensor angles with those of their respective body segment based on a known posture. The data capture system was verified comparing the angle of flexion-extension of the knee with the angle obtained by the artificial vision system from the sagittal plane and comparing it with bands of normality. As a result, it was possible to implement a low-cost inertial motion capture system for the analysis of human gait, with its respective graphical interface to visualize the orientation, flexion-extension angles for each segment and joint of the lower limbs. It is concluded that is possible to develop a complete tool for the kinematic analysis of human gait with the information of the artificial vision system or an anthropometric model.Item Embedded system for electrical load characterization based on artificial neuronal networks in the management of electrical demand in a domotic system(Springer, 2020-08-11) Suaza Cano, Kevin Andrés; Angulo Gamboa, Ángel Stiven; Castillo García, Javier FerneyA load characterization system was developed in an embedded platform, in order to identify electrical devices used in the home. For the characterization process, the most representative electrical parameters of the different loads were defined, which were used in the training of an artificial neural network implemented in an embedded platform with a network topology with the best performance in terms of computational resources, time of execution and percentage of error. The network topologic had two hidden layers each one with 10 neurons. With the characterization of electrical charges, an intelligent home automation system could be created which can generate savings of up to 23% compared to traditional home automation systems or 69% savings compared to a home without any automation or system control. The proposed demand management system can actively manage the loads due to the knowledge of the elements connected to the network, identifying periods of low consumption which can be related to charging processes completed in mobile phones, laptops or standby mode for televisions. The identification of charges facilitates the implementation of management schemes and control of electric charges.Item Synthesis, characterization, and redox potential properties of a new double-stranded Ni-bis(hydrazone)-based helicate(Academic Press Inc., 2020-08-25) Villada, Juan D.; Carmona Vargas, Christian C.; Alcides Ellena, Javier; Ayala, Alejandro P.; Ramírez Pradilla, Juan S.; Combariza, M. Y.; Galarza, Esperanza; D'Vries, Richard Fernando; Chaur, Manuel N.Herein we report the synthesis and structural characterization of a new Ni-bis(hydrazone) complex with the chemical formula [Ni2(L)2(Cl)2](Cl)2·2H2O (L = 2-(heptylthio)-4,6-bis(2-((E)-pyridin-2-ylmethylene)hydrazineyl)pyrimidine). Suitable crystals for X-ray diffraction showed the supramolecular interactions of this complex to exhibit a helical structure coordinating two Ni2+ metal ions bounded by two 2-(heptylthio)-4,6-bis(2-((E)-pyridin-2-ylmethylene)hydrazineyl)pyrimidine ligands. In addition, exploitation of the electrochemical properties by cyclic voltammetry, for this helicate, showed catalyzing ability for the reduction of H+ to H2.Item Natural sucrose esters: Perspectives on the chemical and physiological use of an under investigated chemical class of compounds(Elsevier Ltd, 2020-06-20) Mora Vargas, Jorge Andrés; Orduña Ortega, Julieth; Metzker, Gustavo; Larrahondo, Jesús Eliecer; Boscolo, MaurícioThe present review describes the chemistry and physiological properties of the sucrose esters (SEs) obtained from natural or synthetic pathways, with emphasis on those that have aliphatic and phenylpropanoid substituents on their sucrose moiety. Synthesis, extraction and characterization methods for the SEs and NSEs are discussed in terms of synthetic procedures, separation techniques and spectroscopic methods. The physiological properties are discussed taking into account the nature of the substituent groups and their regiochemistry (position and number of substitutions) on the sucrose moiety.Item Automatic detection of Voice Onset Time in voiceless plosives using gated recurrent units(Elsevier Inc., 2020-05-27) Arias Vergara, Tomás; Argüello Vélez, Patricia; Vásquez Correa, Juan Camilo; Nöth, Elmar; Schuster, Maria Elke; González Rátiva, María Claudia; Orozco Arroyave, Juan RafaelVoice Onset Time (VOT) has been used by researchers as an acoustic measure in order to gain some understanding about the impact of different motor speech disorders in speech production. However, VOT values are usually obtained manually, which is expensive and time consuming. In this paper we proposed a method for the automatic detection of VOT based on pre-trained Recurrent Neural Networks with Gated Recurrent Units (GRUs). Speech recordings from 50 Spanish native speakers from Colombia (25 male) are considered for the experiments. The recordings include the utterance of the diadochokinesis task /pa-ta-ka/ which is typically used for the evaluation of motor speech disorders like those caused due to Parkinson's disease. Additionally, the diadochokinesis task allows us to train a system to detect the VOT of voiceless plosive sounds in intermediate positions. Acoustic analysis is performed by extracting different temporal and spectral features from the recordings. According to the results, it is possible to detect the VOT with F1-score values of 0.66 for Image 1, 0.75 for Image 2, and 0.78 for Image 3 when the predicted values are compared with respect to the manual VOT labels.Item Chain-like uranyl-coordination polymer as a bright green light emitter for sensing and sunlight driven photocatalysis(Royal Society of Chemistry, 2020-07-02) Gomez, Germán E.; Onna, Diego; D'Vries, Richard Fernando; Barja, Beatriz C.; Alcides Ellena, Javier; Narda, Griselda Edith; Soler-Illia, G. J.A.A.A new uranyl-coordination polymer (UCP) has been solvothermally synthesized employing succinic acid and 1,10-phenanthroline (phen) as ligands. The obtained compound with the formula [(UO2)2(phen)(succ)0.5(OH)(O)4(μ3-O)(H2O)]·H2O (UNSL-1) is classified as 1D chains showing I0O1 connectivity. Also, the asymmetric unit is composed of two hepta-coordinated uranyl centers: U1 is surrounded by five oxygen atoms from succinate, while U2 is surrounded by two nitrogen atoms from phen and three oxygen atoms from succinate ([U1O7] and [U2N2O5]). The secondary-building unit (SBU) is composed of a sharing edge tetrameric cluster linked with a succinate ligand in the [−1 0 1] direction. Besides, the chains are reinforced by π–π stacking interactions between the aromatic rings of the phen molecules to conform a 2D supramolecular arrangement. Moreover, photoluminescence experiments show strong green emission consistent with uranyl crystalline materials. Photophysical characterization was completed via low-temperature measurements (77 K) and recording the decay emission for calculating the lifetime (τobs) value. Regarding its multifunctional properties, a cation-sensing performance was achieved showing selective quenching toward iron ions in aqueous media. Finally, UNSL-1 was tested as an efficient water photocatalyst for dye degradation under simulated sunlight irradiation, exhibiting promising results for organic-pollutant water remediation.Item Multiple Reversible Dynamics of Pyrimidine Based Acylhydrazones(Wiley-VCH Verlag, 2020-05-08) Arango, Alejandra M.; Wist, Julien; Ellena, Javier Alcides; D'Vries, Richard Fernando; Chaur, Manuel N.We employed (Z)‐N'‐[phenyl(pyrimidin‐2‐yl)methylene]nicotinohydrazide (2) and (Z)‐4‐(dimethylamino)‐N'‐[phenyl(pyrimidin‐2‐yl)methylene]benzohydrazide (3) as cores of dynamic chemical systems whose different states are modulated, in a reversible fashion, through specific physical and chemical stimuli. The structure of the compounds was determined by Nuclear Magnetic Resonance (NMR) techniques (1D and 2D) and confirmed by single‐crystal X‐ray diffraction. By Variable temperature (VT) 1H NMR experiments and DFT calculations, the conformational isomerism of 2 was studied and added as an additional input for the dynamic system. Additionally, 2 exhibits configurational E/Z isomerization mediated by pH variations and UV light. On the other hand, configurational isomerism locks an unlocks a tridentate pocket for metal cation coordination in both 2 and 3. All the different dynamic states configurational/conformational isomerism and locked and unlocked coordination constitute a development in the field of systems of multiple dynamics suitable for molecular machines.Item Psychometric properties of validity and reliability of an instrument for the rehabilitation of people with disabilities(Ediciones Doyma, S.L., 2020-04-28) Peña Hernández, Paula Andrea; Arenas Quintana, Bellazmin; Gómez Ramírez, Esperanza; Calvo Soto, Andrea PatriciaIntroducción: El ciclo de rehabilitación se caracteriza por contribuir efectivamente en la calidad de vida y estimular la integración de las personas con discapacidad a sus diferentes roles. Objetivo: El propósito de este estudio fue demostrar las propiedades psicométricas de validez y fiabilidad del instrumento para medir el alcance de las acciones de los fisioterapeutas en el ciclo de rehabilitación de personas con discapacidad. Método: Este instrumento (42 ítems) se aplicó a una muestra de 118 fisioterapeutas colombianos de diferentes regiones del país. La validez del contenido fue realizada por 5 expertos mediante una matriz de validación y por una prueba piloto con 10 fisioterapeutas con características semejantes a las de la muestra. La validez de confiabilidad se estableció por homogeneidad con alfa de Cronbach y la de constructo mediante análisis factorial de extracción. Resultados: La prueba KMO para validez de constructo resultó en 0,763, y la prueba de Bartlett con un p-valor prácticamente igual a cero. Los ítems 9, 36, 37 y 42 explican más del 80% de la varianza y el coeficiente alfa de Cronbach global resultó en 0,946. Conclusiones: Se han obtenido resultados que sugieren la pertinencia del uso de este cuestionario como instrumento de recogida de datos para la investigación sobre las acciones en el ciclo de rehabilitación de personas con discapacidad en fisioterapeutas colombianos.