Now showing items 1-20 of 1492

    • Association Between Procrastination And Academic Stress In Peruvian Second-Year Medical Students

      León, Eduardo Orco; Saldívar, Daphne Huamán; Rodríguez, Susel Ramírez; Torreblanca, Jonathan Torres; Salvador, Linder Figueroa; Mejia, Christian R.; Reyes, Ibraín Enrique Corrales (Editorial Ciencias Medicas, 2022-01-01)
      Introduction: University medical students are a population exposed to a high academic load, high level of exigency, high demand of time and there are factors that can affect the effectiveness of academic performance, such as stress and procrastination. Objective: Evaluate the association between stress and procrastination in a pilot sample of medical students at a university in Lima, Peru. Material and methods: A cross-sectional analytical study was conducted, where medical students from the Research Methodology course were recruited at a university in the Peruvian capital. In them, stress and procrastination were measured, both with previously validated tests, then these variables were related and adjusted according to their sex and age. For analytical statistics, generalized linear models were used and p-values ≤ 0.05 were considered statistically significant. Results: When performing the multivariate analysis, it was found that there was a relationship between procrastination and male gender (p = 0.001), age (p = 0.035) and stress (p = 0.022) of the respondents. Conclusions: Procrastination maintains in the sample studied an important association with the stress that students have, as well as with their gender and age.
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    • Does Breast-Conserving Surgery with Radiotherapy have a Better Survival than Mastectomy? A Meta-Analysis of More than 1,500,000 Patients

      De la Cruz Ku, Gabriel; Karamchandani, Manish; Chambergo-Michilot, Diego; Narvaez-Rojas, Alexis R.; Jonczyk, Michael; Príncipe-Meneses, Fortunato S.; Posawatz, David; Nardello, Salvatore; Chatterjee, Abhishek (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      Background: There have been conflicting studies reporting on survival advantages between breast-conserving surgery with radiotherapy (BCS) in comparison with mastectomy. Our aim was to compare the efficacy of BCS and mastectomy in terms of overall survival (OS) comparing all past published studies. Methods: We performed a comprehensive review of literature through October 2021 in PubMed, Scopus, and EMBASE. The studies included were randomized controlled trials (RCTs) and cohorts that compare BCS versus mastectomy. We excluded studies that included male sex, stage 0, distant metastasis at diagnosis, bilateral synchronous cancer, neoadjuvant radiation/chemotherapy, and articles with incomplete data. We performed a meta-analysis following the random-effect model with the inverse variance method. Results: From 18,997 publications, a total of 30 studies were included in the final analysis: 6 studies were randomized trials, and 24 were retrospective cohorts. A total of 1,802,128 patients with a follow-up ranging from 4 to 20 years were included, and 1,075,563 and 744,565 underwent BCS and mastectomy, respectively. Among the population, BCS is associated with improved OS compared with mastectomy [relative risk (RR) 0.64, 95% confidence interval (CI) 0.55–0.74]. This effect was similar when analysis was performed in cohorts and multi-institutional databases (RR 0.57, 95% CI 0.49–0.67). Furthermore, the benefit of BCS was stronger in patients who had less than 10 years of follow-up (RR 0.54, 95% CI 0.46–0.64). Conclusions: Patients who underwent BCS had better OS compared with mastectomy. Such results depicting survival advantage, especially using such a large sample of patients, may need to be included in the shared surgical decision making when discussing breast cancer treatment with patients.
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    • Identifying RO9021 as a Potential Inhibitor of PknG from Mycobacterium tuberculosis: Combinative Computational and in Vitro Studies

      Arica-Sosa, Alicia; Alcántara, Roberto; Jiménez-Avalos, Gabriel; Zimic, Mirko; Milón, Pohl; Quiliano, Miguel (American Chemical Society, 2022-06-14)
      Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb). Despite being considered curable and preventable, the increase of antibiotic resistance is becoming a serious public health problem. Mtb is a pathogen capable of surviving in macrophages, causing long-Term latent infection where the mycobacterial serine/threonine protein kinase G (PknG) plays a protective role. Therefore, PknG is an important inhibitory target to prevent Mtb from entering the latency stage. In this study, we use a pharmacophore-based virtual screening and biochemical assays to identify the compound RO9021 (CHEMBL3237561) as a PknG inhibitor. In detail, 1.5 million molecules were screened using a scalable cloud-based setup, identifying 689 candidates, which were further subjected to additional screening employing molecular docking. Molecular docking spotted 62 compounds with estimated binding affinities of-7.54 kcal/mol (s.d. = 0.77 kcal/mol). Finally, 14 compounds were selected for in vitro experiments considering previously reported biological activities and commercial availability. In vitro assays of PknG activity showed that RO9021 inhibits the kinase activity similarly to AX20017, a known inhibitor. The inhibitory effect was found to be dose dependent with a relative IC50value of 4.4 ± 1.1 μM. Molecular dynamics simulations predicted that the PknG-RO9021 complex is stable along the tested timescale. Altogether, our study indicates that RO9021 is a noteworthy drug candidate for further developing new anti-TB drugs that hold excellent reported pharmacokinetic parameters.
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    • Association between time of residence and self-perception of distress, interpersonal relationships, and social role in Venezuelan immigrants in Lima, Peru 2018–19: mixed-methods study

      Delgado-Cáceres, Frank Milton; Silva-Parra, Kevin Angel; Torres-Slimming, Paola A. (BioMed Central Ltd, 2022-12-01)
      Background: Immigrants arriving in a new country face changes that affect their social, employment, and migratory status. We carried out a mixed-methods study in the rapidly growing Venezuelan immigrant population in Lima, Peru. The objective was to determine whether there was an association between time in Peru and self-perception of symptom distress (SD), interpersonal relationships (IR), and social role (SR). Methods: The quantitative central component consisted of a cross-sectional study, surveying 152 participants using the Outcome Questionnaire 45.2 (OQ-45.2). The qualitative component, based on phenomenology, explored experiences and challenges during the migration process. Semi-structured in-depth interviews were conducted in 16 informants. Results: An association that was observed was the increase in the risk of clinically significant SR score with additional years of age. All informants mentioned having witnessed or experienced xenophobia in Peru. Every informant stated that significant labor differences existed between the countries. The most reported somatic symptoms were symptoms of anxiety and alterations of sleep. Additionally, no informant expressed a desire to remain in Peru long term. Conclusions: A minority of participants registered a clinically significant total score and in each of the three domains of SD, IR, and SR. No association between months in Lima and the self-perception of distress was found. However, this could be due to the short amount of time spent in Peru and any change in self-perception might only be perceived after years or decades spent in Peru. This study is one of the first to use mixed-methods to explore the mental health of the immigrant Venezuelan population.
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    • Prognostic value of albumin-to-globulin ratio in COVID-19 patients: A systematic review and meta-analysis

      Ulloque-Badaracco, Juan R.; Mosquera-Rojas, Melany D.; Hernandez-Bustamante, Enrique A.; Alarcón-Braga, Esteban A.; Herrera-Añazco, Percy; Benites-Zapata, Vicente A. (Elsevier Ltd, 2022-05-01)
      Background and aims: The albumin-to-globulin ratio (AGR) has been used to predict severity and mortality in infectious diseases. The aim of this study is to evaluate the prognostic value of the AGR in COVID-19 patients. Methods: A systematic review and meta-analysis were conducted. We included observational studies assessing the association between the AGR values upon hospital admission and severity or all-cause mortality in COVID-19 patients. In the meta-analyses we used random effect models. Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). The effect measures were expressed as mean difference (MD) and their 95% confidence intervals (CI). We performed Egger's test and funnel plots to assess the publication bias. Results: The included studies had a total of 11356 patients corresponding to 31 cohort studies. Severe COVID-19 patients had lower AGR values than non-severe COVID-19 patients (mean difference (MD), −0.27; 95% IC, −0.32 to −0.22; p < 0.001; I2 = 88%). Non-survivor patients with COVID-19 had lower AGR values than survivor patients (MD, −0.29; 95% IC, −0.35 to −0.24; p < 0.001; I2 = 79%). In the sensitivity analysis, we only included studies with low risk of bias, which decreased the heterogeneity for both outcomes (severity, I2 = 20%; mortality, I2 = 5%). Conclusions: Low AGR values upon hospital admission were found in COVID-19 patients with a worse prognosis.
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    • Consumption of Herbal Supplements or Homeopathic Remedies to Prevent COVID-19 and Intention of Vaccination for COVID-19 in Latin America and the Caribbean

      Bendezu-Quispe, Guido; Benites-Meza, Jerry K.; Urrunaga-Pastor, Diego; Herrera-Añazco, Percy; Uyen-Cateriano, Angela; Rodriguez-Morales, Alfonso J.; Toro-Huamanchumo, Carlos J.; Hernandez, Adrian V.; Benites-Zapata, Vicente A. (MDPI, 2022-06-01)
      Users of complementary and alternative medicine (CAM) have a lower intention to receive vaccines. Furthermore, Latin America and the Caribbean (LAC) region are among the most affected areas by the COVID-19 pandemics and present a high proportion of CAM users. Therefore, this study evaluates the association between the consumption of herbal supplements or homeopathic remedies to prevent COVID-19 and the intention to vaccinate against COVID-19 in the LAC region. We conducted a secondary data analysis of a Massachusetts Institute of Technology (MIT) survey with Facebook to assess COVID-19 beliefs, behaviours, and norms. Crude and adjusted prevalence ratios (aPR) with their respective 95% confidence intervals (95% CI) were calculated using generalized linear models of the Poisson family with the log link function. The prevalence of the use of products to prevent COVID-19 was the following: consumption of herbal supplements (7.2%), use of homeopathic remedies (4.8%), and consumption of garlic, ginger, and lemon (11.8%). An association was found between using herbal supplements (19.0% vs. 12.8%; aPR = 1.44; 95% CI: 1.30–1.58), the use of homeopathic remedies (20.3% vs. 12.3%; aPR = 1.58; 95% CI: 1.25–1.98), and the consumption of garlic, ginger, and lemon (18.9% vs. 11.9%; aPR = 1.55; 95% CI: 1.50–1.61) and non-intention to vaccinate against COVID-19. In the LAC population, there is an association between using herbal supplements, using homeopathic remedies and consuming garlic, ginger, and lemon to prevent infection by COVID-19 and non-intention to vaccinate against this disease. Therefore, it is necessary to design targeted strategies for groups that consume these products as preventive measures against COVID-19 to increase vaccination coverage and expand the information regarding transmission and prevention strategies for SARS-CoV-2.
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    • GC-MS Profile, Antioxidant Activity, and in Silico Study of the Essential Oil from Schinus molle L. Leaves in the Presence of Mosquito Juvenile Hormone-Binding Protein (mJHBP) from Aedes aegypti

      Herrera-Calderon, Oscar; Chavez, Haydee; Enciso-Roca, Edwin Carlos; Común-Ventura, Pablo Williams; Hañari-Quispe, Renan Dilton; Figueroa-Salvador, Linder; Loyola-Gonzales, Eddie Loyola; Pari-Olarte, Josefa Bertha; Aljarba, Nada H.; Alkahtani, Saad; Batiha, Gaber El Saber (Hindawi Limited, 2022-01-01)
      Schinus molle is a medicinal plant used as an anti-inflammatory and for rheumatic pain in the traditional medicine of Peru. On the other hand, Aedes aegypti is the main vector of several tropical diseases and the transmitter of yellow fever, chikungunya, malaria, dengue, and Zika virus. In this study, the aim was to investigate the antioxidant activity in vitro and the insecticidal activity in silico, in the presence of the mosquito juvenile hormone-binding protein (mJHBP) from Aedes aegypti, of the essential oil from S. molle leaves. The volatile phytochemicals were analyzed by gas chromatography-mass spectrometry (GC-MS), and the profile antioxidants were examined by DPPH, ABTS, and FRAP assays. The evaluation in silico was carried out on mJHBP (PDB: 5V13) with an insecticidal approach. The results revealed that EO presented as the main volatile components to alpha-phellandrene (32.68%), D-limonene (12.59%), and beta-phellandrene (12.24%). The antioxidant activity showed values for DPPH=11.42±0.08 μmol ET/g, ABTS=134.88±4.37 μmol ET/g, and FRAP=65.16±1.46 μmol ET/g. Regarding the insecticidal approach in silico, alpha-muurolene and gamma-cadinene had the best biding energy on mJHBP (ΔG=-9.7 kcal/mol), followed by beta-cadinene (ΔG=-9.5 kcal/mol). Additionally, the volatile components did not reveal antioxidant activity, and its potential insecticidal effect would be acting on mJHBP from A. aegypti.
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    • Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio as risk factors for mortality in Peruvian adults with chronic kidney disease

      Umeres-Francia, Gianfranco Eddú; Rojas-Fernández, María Valentina; Herrera-Añazco, Percy; Benites-Zapata, Vicente Aleixandre (BioMed Central Ltd, 2022-12-01)
      Objective: To assess the association between the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) with all-cause mortality in Peruvian patients with chronic kidney disease (CKD) attending a tertiary hospital. Methods: We conducted a retrospective cohort study in adults with CKD in stages 1–5. The outcome variable was mortality and as variables of exposure to NLR and PLR. Both ratios were categorized as high with a cutoff point of 3.5 and 232.5, respectively. We carried out a Cox regression model and calculated crude and adjusted hazard ratios (HR) with their 95% confidence interval (95% CI). Results: We analyzed 343 participants with a mean age of 78.3 (± 11.9) years and 62.9% (n = 216) men. The median follow-up time was 2.45 years (2.08–3.08), and the frequency of deaths was 17.5% (n = 60). The mortality of patients with high NLR was 28% compared to 15.7% of the group with normal NLR, and the mortality was 35.7% in those with high PLR and 15.6% in those with normal PLR. In the crude analysis, the high NLR and PLR were significantly associated with all-cause mortality (HR = 2.01; 95% CI 1.11–3.66) and (HR = 2.58; 95% CI 1.31–5.20). In the multivariate model, after adjusting for age, sex, serum creatinine, albumin and hemoglobin, the high NLR and PLR remained as independent risk factors for all-cause mortality (aHR = 1.97; 95% CI 1.05–3.69) and (aHR = 2.62; 95% CI 1.25–5.51), respectively. Conclusion: Our study suggests the relationship between high NLR and PLR with all-cause mortality in patients with CKD.
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    • Acceptance towards COVID-19 vaccination in Latin America and the Caribbean: A systematic review and meta-analysis

      Alarcón-Braga, Esteban A.; Hernandez-Bustamante, Enrique A.; Salazar-Valdivia, Farley E.; Valdez-Cornejo, Valeria A.; Mosquera-Rojas, Melany D.; Ulloque-Badaracco, Juan R.; Rondon-Saldaña, Jenny C.; Zafra-Tanaka, Jessica H. (Elsevier Inc., 2022-09-01)
      Introduction: Vaccination represents an important strategy to mitigate COVID-19 related morbidity and mortality by protecting against severe forms of the disease and reducing hospitalization and death rates. In this sense, the objective of this study is to estimate the prevalence of Vaccination Intention (VI) against COVID-19 in Latin America and Caribbean (LAC). Methods: We conducted a systematic review with a comprehensive search strategy for the following databases: PubMed, Scopus and Web of Science. A random-effect model meta-analysis was carried out using observational studies assessing the intention to vaccines against COVID-19 in LAC countries. The Clopper-Pearson method was used to estimate 95% Confidence Intervals. The quality assessment was developed using the Newcastle-Ottawa Scale adapted for cross-sectional studies. A subgroup analysis by study location and a sensitivity analysis were developed. Results: Nineteen cross-sectional studies were included. Five meta-analyzes were performed according to the target population of the included studies. The VI in the general population of LAC was 78.0% (95%CI: 74.0%–82.0%). The VI for non-pregnant women was 78.0% (95%CI: 58.0%–99.0%), for elderly population was 63.0% (95%CI: 59.0%–69.0%), for pregnant women was 69.0% (95%CI: 61.0%–76.0%) and for health-personnel was 83.0% (95% CI: 71.0%–96.0%). The sensitivity analysis for general population meta-analysis that included only low risk of bias studies showed a 77.0% VI (95%CI: 73.0%–82.0%) and for non-pregnant women, 85.0% VI (95%CI: 79.0%–90.0%). Conclusion: Despite the high prevalence of VI in general population found in our study, VI prevalence from elderly people and pregnant women are lower than other population groups and overall population.
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    • Transtibial Electromechanical Prosthesis Based on a Parallel Robot: A Innovate Review

      Huamanchahua, Deyby; Osores-Aguilar, Diego; Leon-Sales, Victor Andre; Valenzuela-Lino, Yadhira S.; Huallanca-Escalera, Harold (Institute of Electrical and Electronics Engineers Inc., 2022-01-01)
      In recent years, the development of prosthetic limbs has increased due to the various studies that have been carried out around Biomechanics. These technological advances have allowed many amputee patients to return to their daily activities and, in some cases, to recover their social life. However, there are still limitations for some types of prostheses such as passive prostheses, mainly those intended for people with transtibial amputations since they do not perform the physiological function of the joints. Therefore, in-depth research on transtibial prostheses has been carried out. The search period spans from the year 2018 to the year 2021. Information was considered in a simplified and well-structured manner on the design of a transtibial electromechanical prosthesis. Therefore, we will analyze its main features related to its design and application in the patient.
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    • Knee and Ankle Exoskeletons for Motor Rehabilitation: A Technology Review

      Huamanchahua, Deyby; Otarola-Ruiz, Cesar Luciano; Quispe-Pina, Ana; De La Torre-Velarde, Elvis J. (Institute of Electrical and Electronics Engineers Inc., 2022-01-01)
      Exoskeletons have been around since 1890 when a passive device was developed to assist movement. Although the exoskeleton initially focused on the whole body, it has become increasingly focused on a more specific area, which makes rehabilitation work more feasible and, consequently, less costly. Therefore, the purpose of the article is to present a systematic review of trends in the technical area of knee and ankle exoskeletons for rehabilitation purposes. The objective is to provide the interested researcher with a structured matrix that integrates essential components and mechanisms in the development of knee and ankle exoskeletons. As a methodology, specialized databases in biomechanics were used that aided in the collection of research conducted between 2019 and 2022. The filtering process resulted in the selection of 37 investigations. Finally, it was concluded that innovations in exoskeletons contribute to patient rehabilitation and that there is still room for further improvement in the implementation of projects on a commercial scale and the development of new exoskeletons based on previous research.
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    • A Strategy of Potential Fields and Neural Networks in the Control of an Autonomous Vehicle Within Dangerous Environments

      Chávez, Luisa; Cortez, Angel; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      This article focuses on the development of an autonomous navigation system by generating real-time 3D maps of different urban environments with different properties within simulation software. This system used the Pioneer 3-DX vehicle, a LiDAR sensor, GPS, and a gyroscope. For the elaboration of the trajectory, the mathematical tool of artificial potential fields was used, which will generate an attractive field to a dynamic goal identified by the robot and repulsive to the obstacles present in the environment, recognized with great precision thanks to the use of a neural network. The topology neural network 8–16–32 was developed using forward propagation, reverse propagation, and gradient descent algorithms. By combining the tools of potential fields and neural networks, a path was traced through which the robotic system will be able to move freely under an off-center point kinematic control algorithm. Finally, a 3D map of the environment was obtained to provide information on the morphology and most outstanding characteristics of the deployment environment to users who use the system.
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    • An Optimal Blade Design for Mini Wind Generators Mountable on the Spoiler of a Vehicle

      del Riego, Daniel Gonzalez; Gómez, Gabriel; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      In this work, a mini wind turbine was developed that takes advantage of the kinetic energy of the winds around a moving car. The blades were designed according to inclination angles in order to capture as much energy as possible without greatly affecting the performance of the vehicle. Various proposals are presented according to the inclination of the angle of the blades with respect to the axis of the turbine. Likewise, the behavior of airflow over the blades will be studied using CFD techniques. In addition, it will be possible to obtain various parameters such as the drag coefficient that will serve for the optimal design of the turbines. Finally, experimentation will be carried out to evaluate the electrical energy that said turbine can produce when coupled to a mini generator. The results show that the most optimal design is proposal 2 because it is the one that produces more voltage with less drag force.
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    • Design of a Pisco Sour Vending Machine Based on an Embedded System (Raspberry Pi)

      Achuy, Jesús; Arestegui, Renzo; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      Pisco Sour is a traditional Peruvian cocktail made with pisco, egg white, sweetening syrup, and lemon juice. The preparation of this cocktail is made traditionally by a bartender following a recipe according to standardized preparation steps and quantities. The present research developed a vending machine to standardize the quantities of the ingredients, reduce the preparation time and guarantee the homogeneity of the product. The control is done with a Raspberry Pi 3, the dosing of the ingredients, through the development of different mechatronic systems, the pisco, sweetening syrup, and egg white enter through the use of peristaltic pumps to dispense exact amounts; it has a lemon squeezing and cutting system and, finally, the refrigeration system to keep all the ingredients fresh. The integration of the system avoids the loss of ingredients and reduces costs. As a result, the machine, compared to a bartender, maintains a uniform consumption of ingredients and a constant preparation time in a batch of more than 50 glasses of Pisco Sour.
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    • A Design of a Spindle and Mathematical Calculations of the Speed Required for HDPE Plastic Extrusion and Recycled PETG Plastic to Obtain 40 kg/h of Filaments 3 mm Thick

      Robledo, Ana Fernanda; Gambini, Patsy; Vinces, Leonardo; Klusmann, Mirko (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      The present article proposes to show the mathematical design of a spindle and the speed that it requires, using mathematical formulas, to carry out the extrusion process of recycled PETG or HDPE plastic. Speed control in this process is of great importance because the quality of the filament to be obtained will depend on it. The study will be simulated on spindles and casing that are 3640 and 3890 mm long respectively and made of AISI 4140 steel. The spindle casing has 3 types of band resistors, which vary their temperature according to the material to be used: PETG plastic or HDPE plastic. Each band type resistor is found in each section that the spindle has; the screw has 3 stages called the feeding zone, the compression zone, and the dosing zone. The production capacity is 40 kg /h of PETG or HDPE plastic filament 3 mm thick. In conclusion, the present method consists of the mathematical design of a spindle for the extrusion of both materials, calculation of speeds, and the simulation of the behavior of the fluid.
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    • Large-Scale FDM 3D Printing in 6 Degrees of Freedom on One ARM KUKA KR 60

      Chicoma, Max Uriarte; Escobar, Diego Serrano; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      3D printing is widely used due to its versatility and low manufacturing cost, but this manufacturing method has limitations such as the use of only 3 degrees of freedom that consists of extrusion by layers contained in the XY plane with displacement high on the Z-axis. On the other hand, there is the printing volume which is reduced, and finally the loss of material that occurs when having supports. Next, a versatile procedure is presented, which is mounted on a KUKA KR60 robotic arm, with which complex surfaces can be printed and of a larger size with the help of the robot arm's work area, parts with concave surfaces, and convex where printing supports are removed. This proposal intended to have a printer mounted on a KUKA KR60 robotic arm with which you can have 6 degrees of freedom, and use approximately the cubic meter of freedom that the arm has. This achieves prints with greater complexity and volume of approximately 1 m3, in addition to being able to eliminate the waste of material that occurs in conventional 3D printing. Also, in parallel, it is possible to generate the codes for a generic printing plate that is compatible with G-CODE and for the robotic arm module.
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    • Simulation of a System for Reducing Gases Emitted in a Steel Casting Process by Two-Stage Centrifugal Separation

      Mulatillo, Alberto; Sernaque, Carla; Ronceros, Julio; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      This study proposes the simulation of a system for reducing polluting gases produced by a steel foundry by two-stage centrifugation. This simulation seeks to verify the physical principle of centrifugation in two cyclones (Stairmand and Swift types) in serial connection: one with its inlet at the outlet of the other, based on initial gas inlet conditions, as well as the design equations of this equipment. Likewise, it's intended to demonstrate the efficiency of this system by entering the mass composition of the gas, in particulate matter (PM) terms, measuring its new composition at the output, after simulating the gas and particle dynamics. For this, Ansys CFD and Ansys Fluent software are used (with previous data analysis and processing), and Python programming techniques to automate calculations and obtain the optimal design values for the cyclones. This system seeks to be an alternative to a universe of expensive and enormous equipment related to environmental pollution control.
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    • Design of a Hydrodynamic Profile for an Unmanned Underwater Device Using Numerical Simulation

      Tocón, Axl; Vásquez, Cristian; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      The present work proposes the design of a hydrodynamic profile for unmanned submarine devices through numerical simulation, thus facilitating experimental studies and reducing manufacturing costs. Design and manufacturing aspects of different authors were studied to establish a highly maneuverable vehicle, capable of moving in the horizontal and vertical plane. For this reason, the final design proposes hydrodynamic profiles in the bow and stern using the “Myring” equations. It also has cross-shaped hydrodynamic fins located in the bow, which will help reduce the drag coefficient. Therefore, this work aims to study and analyze the hydrodynamic characteristics of the submarine using the ANSYS Fluent software. Likewise, the drag coefficient will be analyzed for different operating speeds, in order to know what is the maximum drag force that should be overcome to move at that speed. Finally, it was observed that the results obtained from the simulations are values quite similar to those obtained through hydrodynamic formulas or experimental tests.
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    • A Thermal Analysis of the Internal Flow in 2 Helical Coils for the Delignification Process of Sugar Cane Bagasse Using Superheated Steam

      Loayza, Juan Carlos; Ronceros, Julio; Vinces, Leonardo (Springer Science and Business Media Deutschland GmbH, 2022-01-01)
      The present work proposes an analysis of the internal temperature flow in two types of helical coils, whose number of turns is 6 and 10, for the sugar cane bagasse delignification process, using superheated steam as a heat source. The analysis seeks to find the ideal number of turns for the process, the inlet pressure, and the temperature range in which the coil should operate to provide the working temperature for the reaction. This proposal will be carried out using Ansys fluent version 19.2 educational simulation software, where the coils were designed and the temperature and pressure parameters of the superheated steam flow to travel through the internal part of the helical coil were introduced. As a result, with a number of coils of 10 and an inlet pressure of 0.4 MPa, an efficiency of 96.545% was achieved to maintain the temperature along the coil path. This allows its application for bagasse delignification.
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    • Efficacy and harms of tocilizumab for the treatment of COVID-19 patients: A systematic review and meta-analysis

      Piscoya, Alejandro; del Riego, Angela Parra; Cerna-Viacava, Renato; Rocco, Jonathon; Roman, Yuani M.; Escobedo, Angel A.; Pasupuleti, Vinay; Michael White, C.; Hernandez, Adrian V. (Public Library of Science, 2022-06-01)
      Introduction We systematically assessed benefits and harms of tocilizumab (TCZ), which is an antibody blocking IL-6 receptors, in hospitalized COVID-19 patients. Methods Five electronic databases and two preprint webpages were searched until March 4, 2021. Randomized controlled trials (RCTs) and inverse probability treatment weighting (IPTW) cohorts assessing TCZ effects in hospitalized, COVID-19 adult patients were included. Primary outcomes were all-cause mortality, clinical worsening, clinical improvement, need for mechanical ventilation, and adverse events (AE). Inverse variance random-effects meta-analyses were performed with quality of evidence (QoE) evaluated using GRADE methodology. Results Nine RCTs (n = 7,021) and nine IPTW cohorts (n = 7,796) were included. TCZ significantly reduced all-cause mortality in RCTs (RR 0.89, 95%CI 0.81–0.98, p = 0.03; moderate QoE) and non-significantly in cohorts (RR 0.67, 95%CI 0.44–1.02, p = 0.08; very low QoE) vs. control (standard of care [SOC] or placebo). TCZ significantly reduced the need for mechanical ventilation (RR 0.80, 95%CI 0.71–0.90, p = 0.001; moderate QoE) and length of stay (MD -1.92 days, 95%CI -3.46 to -0.38, p = 0.01; low QoE) vs. control in RCTs. There was no significant difference in clinical improvement or worsening between treatments. AEs, severe AEs, bleeding and thrombotic events were similar between arms in RCTs, but there was higher neutropenia risk with TCZ (very low QoE). Subgroup analyses by disease severity or risk of bias (RoB) were consistent with main analyses. Quality of evidence was moderate to very low in both RCTs and cohorts. Conclusions In comparison to SOC or placebo, TCZ reduced all-cause mortality in all studies and reduced mechanical ventilation and length of stay in RCTs in hospitalized COVID-19 patients. Other clinical outcomes were not significantly impacted. TCZ did not have effect on AEs, except a significant increased neutropenia risk in RCTs. TCZ has a potential role in the treatment of hospitalized COVID-19 patients.
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