Assessment of buccal bone thickness of aesthetic maxillary region: a conebeam computed tomography study

Ramón Fuentes,Tania Flores,Pablo Navarro,Carlos Salamanca,Víctor Beltrán,Eduardo Borie 대한치주과학회 2015 Journal of Periodontal & Implant Science Vol.45 No.5

Purpose: The aim of this study was to analyze the anatomical dimensions of the buccal bone walls of the aesthetic maxillary region for immediate implant placement, based upon cone-beam computed tomography (CBCT) scans in a sample of adult patients. Methods: Two calibrated examiners analyzed a sample of 50 CBCT scans, performing mor¬phometric analyses of both incisors and canines on the left and right sides. Subsequently, in the sagittal view, a line was traced through the major axis of the selected tooth. Then, a second line (E) was traced from the buccal to the palatal wall at the level of the observed bone ridges. The heights of the buccal and palatal bone ridges were determined at the ma¬jor axis of the tooth. The buccal bone thickness was measured across five lines. The first was at the level of line E. The second was at the most apical point of the tooth, and the other three lines were equidistant between the apical and the cervical lines, and parallel to them. Statistical analysis was performed with a significance level of P≤0.05 for the bone thick¬ness means and standard deviations per tooth and patient for the five lines at varying depths. Results: The means of the buccal wall thicknesses in the central incisors, lateral incisors and canines were 1.14±0.65 mm, 0.95±0.67 mm and 1.15±0.68 mm, respectively. Additionally, only on the left side were significant differences in some measurements of buccal bone thickness observed according to age and gender. However, age and gender did not show significant differences in heights between the palatal and buccal plates. In a few cases, the buccal wall had a greater height than the palatal wall. Conclusions: Less than 10% of sites showed more than a 2-mm thickness of the buccal bone wall, with the exception of the central incisor region, wherein 14.4% of cases were ≥2 mm.

Numerical assessment of the damage-tolerance properties of polyester ropes and metallic strands

Juan F. Beltrán,Tomás P. Bravo 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.1

Experimental and numerical studies have concluded that two of the main phenomena that govern the static response of damaged ropes and strands are the strain localization and asymmetry in damage distribution. In this paper, the dependency of the damage-tolerance properties and the accumulated damage level experienced up to the onset of failure on these two phenomena is investigated. To this end, a nonlinear model that couples the effects of these two phenomena is utilized to study the static response of damaged polyester ropes and metallic (steel and aluminium) strands. In particular, the residual stiffness, the residual strength, the reduction in the deformation capacity, and the accumulated damage, based on residual toughness values, are computed for a wide range of initial damage levels exerted on the ropes and strands. Experimental static tensile test data are used to validate the predictions provided by the nonlinear model in which initial damage levels and specimens diameters vary from 5% to 55% and 6mm to 166 mm respectively. Results indicate that the nonlinear model is capable of establishing the main phenomena that rules specimens response providing an accurate prediction of the damage tolerance-parameters and the damage level accumulated at the onset of specimens failure.

Valorization of rice bran: Modified supercritical CO2 extraction of bioactive compounds

Oscar Benito-Román,Sandra Varona,María Teresa Sanz,Sagrario Beltrán 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

In this work, as afirst step in a comprehensive strategy for the valorization of rice bran, the extraction ofoil using supercritical CO2 and ethanol as cosolvent has been studied. The effect of extractiontemperature (40 and 60 C), pressure (30 and 40 MPa) and amount of ethanol used (0, 5 and 10%) has beenconsidered. The quality extracted oil has been evaluated in terms of antioxidant activity, fatty acid profileand bioactive compounds such as phenolics,flavonoids, g-oryzanols, and tocopherols content. Results revealed that, using neat CO2, the best oil in terms of antioxidant activity was obtained at 40 Cand 30 MPa. However, the addition of ethanol as modifier significantly increased the amount of bioactivemolecules extracted and hence the overall antioxidant activity of the oil, which was maximum at 40 MPaand 10% ethanol, regardless the temperature. The use of ethanol also affected the amount of fatty acidsand g-oryzanols extracted.

Do film reactions affect ozone gas–liquid fast-moderate reaction kinetics in the proximity of gas–water interface?

F.J. Beltrán,F.J. Rivas 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.127 No.-

Kinetics of the ozonation of water contaminants is usually based on mol balance equations applied in thewater bulk. In these models, direct and free radical reactions are considered, neglecting the contributionof reactions developed in the proximity of the gas–water interface. In this work, a theoretical kineticmodel of the ozonation involving direct and free radical reactions in the film and water bulk is carriedout. The model is based on film and penetration absorption theories. Time concentration profiles areassessed by coupling the non-stationary penetration theory with bulk mass balances. Studied variablesare chosen according to their influence on the numbers of Hatta and instantaneous reaction factor. These parameters are equilibrium ozone and compound concentrations, direct rate constant, and masstransfer coefficient. The effect of pH and hydrogen peroxide are studied. Calculated results reveal thatdirect reaction contribution in the film has a significant importance, especially in fast-moderate kineticregimes of ozone absorption. Absence of film free radical reactions leads to compound removal ratesslightly lower than the complete mechanism (fast regimes develop). Formation of hydrogen peroxideand its reaction with ozone leads to the formation of free radicals.

Association between Heart Failure and Clinical Prognosis in Patients with Acute Ischemic Stroke: A Retrospective Cohort Study

Jose Luis Lozano Villanueva,Javier Francisco Torres Zafra,Fabián Cortés Muñoz,Fernán del Cristo Mendoza Beltrán,Jenny Carolina Sánchez Casas,Luis Alfonso Barragán Pedraza 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.2

Background and Purpose Ischemic stroke is a common cause of death worldwide. In clinical practice it is observed that many individuals who have experienced an ischemic stroke also suffer from simultaneous comorbidities such as heart failure, which could be directly associated with a worse clinical prognosis. Therefore, this study analyzed outcomes in terms of the severity of the event, inhospital mortality, duration of hospital stay, and inhospital recurrence of the episode, in order to determine the implications resulting from the presentation of both pathologies. Methods This was a retrospective-cohort, hospital-based study. Results The study included 110 subjects with heart failure (exposed) and 109 subjects without heart failure (nonexposed). The incidence of inhospital mortality was 27.27% in exposed patients and 9.17% in nonexposed patients (p<0.001), and the presence of heart failure increased the risk of death by 92% (p=0.027). According to scores on the National Institutes of Health Stroke Scale, the median severity was worse in exposed than nonexposed patients (16.1 vs. 9.2, p=0.001). The median hospital stay was 9 days in subjects with heart failure and 7 days in nonexposed patients (p=0.011). The rate of inhospital stroke did not differ significantly between exposed and nonexposed patients (1.82% vs. 0.92%, p=0.566). Conclusions Individuals with heart failure who suffer from an acute ischemic stroke show worse clinical outcomes in terms of mortality, event severity, and duration of hospital stay.

Degradation of microalgae from freshwater by UV radiation

M.M. Barrado-Moreno,J. Beltrán-Heredia,J. Martín-Gallardo 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.48 No.-

Algae (Chlorella,Microcystis, Oocystis and Scenedesmus) degradation by ultraviolet radiation has beeninvestigated. The radiation source was a low pressure mercury vapor lamp which emits monochromaticradiation at 254 nm. Experiments include initial algae concentration variation. After a period of exposureto UV radiation, algal mass concentration was reduced by more than 80%. The results were interpretedunder Line Source Spherical Emission model, so quantum yield was the appropriate target variable forexplaining the process. Global quantum yields are determined for Chlorella, Microcystis, Oocystis andScenedesmus being 7.75104, 3.65105, 2.28 105, 1.74104mg E 1, respectively.

User Preferences Related to Multimedia Elements of a Mobile Application to Prevent Diabetes

Yisel Pinillos-Patiño,Yaneth Herazo-Beltrán,Orlando Rodríguez-Cordero,Amada Escorcia-Bermejo,Enrique Martelo-López,José Armando Vidarte-Claros,José Hoover Vanegas García,Gabriela Y. Cortés Moreno 대한의료정보학회 2020 Healthcare Informatics Research Vol.26 No.4

Objectives: To understand user preferences related to the characteristics of an application that promotes and provides educationon healthy habits to correctly design multimedia elements. Methods: We conducted a comprehensive qualitative studywith a hermeneutical strategy, which gathered information using well-researched questions that were posed to focus groupsconsisting of 32 participants. These participants were asked for opinions related to multimedia elements to display educationalmessages about physical activity and healthy eating in a mobile application. There were three analysis categories ofmultimedia elements: text, visual elements, and audio elements. Results: The majority of the participants, 93.75%, were in thelow socioeconomic stratum; 68.75% are in a civil union with their partner; 53.12% completed or failed to complete secondaryschool, and 68.75% were housewives. Based on the qualitative results, we found that mobile applications become mediatingtools that support the adoption of actions that tend to improve lifestyles and increase knowledge about proper nutrition andphysical activity. Text messages used in mobile applications should promote healthy habits and remind users of their benefits. Images and videos should be accompanied by text and audio to provide greater clarity regarding recommendations of healthyhabits. Conclusions: Technology must provide accessibility and coverage opportunities, while meeting the needs and expectationsof users. It should facilitate primary health intervention through education to transform unhealthy behaviors andgenerate lifestyles that improve the health of the user and their family context.

A Novel Discrete-time Nonlinear Model Predictive Control Based on State Space Model

Carlos Sotelo,Antonio Favela-Contreras,Francisco Beltrán-Carbajal,Graciano Dieck-Assad,Pedro Rodríguez-Cañedo,David Sotelo 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

This paper proposes a novel finite dimensional discrete-time Nonlinear Model Predictive Control. This technique is based on discrete-time state-space models, Taylor series expansion for prediction and performance index optimization. Furthermore, the technique extends the concept of the Lie derivative for the discrete time case using Euler backwards method. The performance validation for the discrete-time Nonlinear Model Predictive Control uses the simulation of a single-link flexible joint robot and the inverted pendulum. Comparison of the proposed finite dimensional discrete-time Nonlinear Model Predictive Control technique with Feedback Linearization Control is also discussed. Analytical and numerical results show excellent performances for both, the single-link flexible joint and inverted pendulum controllers using the proposed discrete-time Nonlinear Model Predictive Control technique.

Numerical simulation and design of a parabolic trough solar collector used as a direct generator in a solar-GAX cooling cycle

Daniel Sauceda,Nicolás Velázquez,Octavio García-Valladares,Ricardo Beltrán 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.6

In this work, a solar parabolic trough collector (PTC) has been dimensioned and its technical feasibility has been evaluated in order to be used as ammonia direct vapor generator in an advanced absorption air-cooled Solar-GAX cycle of 10.6 kW cooling capacity. A detailed numerical simulation model that takes into account the geometry and the optical, thermal and fluid dynamic behavior of the PTC has been developed. The model has been solved in order to reach minimal thermal losses through the PTC, and maximum coefficient of performance (COP) of the Solar-GAX cycle. Under design conditions, the solar PTC efficiency, the COP of the Solar-GAX cycle and the global efficiency of the system were 0.62, 0.87 y and 0.54 respectively. The calculated efficiency is 25.5 % higher than that provided by a single effect water-lithium bromide cycle coupled in an indirect form with a solar PTC system.

Adaptive Nonlinear Control of Induction Motor

Gerardo V. Guerrero Ramírez,Luis G. Vela Valdés,Manuel Adam Medina,Carlos D. García Beltrán,Cesar A. Villanueva López 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.1

This work addresses the problem of controlling a rigid arm (one degree of freedom robot manipulator) directly driven by an induction motor. A Lyapunov-based adaptive nonlinear controller is designed. The developed controller compensates for parametric uncertainty associated with the resistance of the rotor windings and it is capable to track asymptotically a trajectory for an angular position keeping all the internal signals bounded and guarantees the asymptotical stability of the system. Simulations are presented to illustrate the performance of this controller.