Universidad San Francisco de Quito (USFQ)
Recent publications
This work presents a hybrid sliding mode controller approach for level control in the nuclear power plant steam generators. In a nuclear power plant, the steam generator is one of the essential pieces of equipment. Therefore, this paper aims at a robust hybrid scheme that merges internal model control concepts, sliding mode control methodology, and gain scheduling using Takagi–Sugeno multimodel fuzzy systems. Since the process presents integrating and inverse response with dead time and a highly dependent response associated with the operating power variability, this work considers process identification like an optimization problem. Hence, parallel processing algorithms such as particle swarm optimization are used. The performance achieved with the new proposal is suitable for set-point tracking and disturbance rejection.
This article intends to provide an update of the needs in the field working in the artificial mitochondrial transfer/transplant (AMT/T), and an overview of the article updates from the special issue "Advances of Mitochondria as a therapeutic agent". In the last 4 decades, scientists developed innovative therapeutic applications based on the AMT/T, inspired by the natural transfer of mitochondria between cells to repair cellular damage or treat diseases. The clinical application of AMT has become the priority for the field involving the replacement or augmentation of healthy mitochondria in the harmed tissue, especially in the treatment of organ ischemia-reperfusion injury. However, we remark in our article that key questions remain to be answer such which one is the best isolation protocol, tissue or cell source for isolation, and others of great importance to move the field forward.
Several studies argue that sponsorship promotes and normalizes gambling behavior because commercial gambling providers (CGPs) act as sponsors for many sports entities. This study examines the effect of articulation on sports sponsorship, sincerity, and congruence as perceived by consumers and betting behavior by comparing a CGP brand with a congruent sponsor brand. Data were collected through an experiment combining the factor of the inter-subject type of sponsor (CGPs sponsor vs. congruence sponsor) and articulation (commercial articulation and no articulation) in 518 subjects from the United Kingdom. The analysis was performed using structural equation modeling and multi-group analysis. Subjects showed a greater willingness to bet when the CGP sponsor was perceived as congruent and sincere compared with congruent sponsorship, suggesting that this type of sponsor could encourage sports betting. However, the elimination of CGPs’ sponsorship is complex because of the significant funding they provide.
Desmoid fibromatosis is a rare, aggressive borderline lesion arising from soft tissues. Treatment will depend on the structures that the tumor has involved. Surgery with negative margins is the recommended strategy as it can usually achieve disease control; however, the tumor's location sometimes does not allow it. Therefore, a combination of medical therapies along with strict surveillance is crucial. We present the case of a 6-month-old boy with a chest mass. After further evaluation, a rapidly growing mediastinal mass involving the sternum and costal cartilage was detected. Desmoid fibromatosis was the final diagnosis.
Forest loss and fragmentation drive widespread declines in biodiversity. However, hummingbirds seem to exhibit relative resilience to disturbance, characterized by increasing abundance alongside declining species richness and evenness. Yet, how widespread this pattern may be, and the mechanisms by which it may occur, remain unclear. To fill in this knowledge gap, we investigated habitat-and site-level patterns of diversity, and community composition of hummingbirds between continuous forest (transects n = 16 in ~3500 ha) and more disturbed surrounding fragments (n = 39, 2.5-48.0 ha) in the Chocó rain forest of northwestern Ecuador. Next, we assessed within-patch and patch-matrix characteristics associated with hummingbird diversity and composition. We found higher hummingbird species richness in forest fragments relative to the continuous forest, driven by increased captures of rare species in fragments. Community composition also differed between continuous forest and fragments, with depressed evenness in fragments. Increased canopy openness and density of medium-sized trees correlated with hummingbird diversity in forest fragments , although this relationship became nonsignificant after applying false discovery rate (p < .01). Higher species richness in fragments and higher evenness in the continuous forest highlight the complex trade-offs involved in the conservation of this ecologically important group of birds in changing Neotropical landscapes. Abstract in Spanish is available with online material.
In this Review, we compare rates of anthropogenic and natural environmental changes in the Amazon and South America and in the larger Earth system. We focus on deforestation and carbon cycles because of their critical roles on the Amazon and Earth systems. We found that rates of anthropogenic processes that affect Amazonian ecosystems are up to hundreds to thousands of times faster than other natural climatic and geological phenomena. These anthropogenic changes reach the scale of millions of square kilometers within just decades to centuries, as compared with millions to tens of millions of years for evolutionary, climatic, and geological processes.
Background Large-scale species monitoring remains a significant conservation challenge. Given the ongoing biodiversity crisis, the need for reliable and efficient methods has never been greater. Drone-based techniques have much to offer in this regard: they allow access to otherwise unreachable areas and enable the rapid collection of non-invasive field data. Herein, we describe the development of a drone-based method for the estimation of population size in Galápagos marine iguanas, Amblyrhynchus cristatus . As a large-bodied lizard that occurs in open coastal terrain, this endemic species is an ideal candidate for drone surveys. Almost all Amblyrhynchus subspecies are Endangered or Critically Endangered according to the IUCN yet since several colonies are inaccessible by foot, ground- based methods are unable to address the critical need for better census data. In order to establish a drone-based approach to estimate population size of marine iguanas, we surveyed in January 2021 four colonies on three focal islands (San Cristobal, Santa Fe and Espanola) using three techniques: simple counts (the standard method currently used by conservation managers), capture mark-resight (CMR), and drone-based counts. The surveys were performed within a 4-day window under similar ambient conditions. We then compared the approaches in terms of feasibility, outcome and effort. Results The highest population-size estimates were obtained using CMR, and drone-based counts were on average 14% closer to CMR estimates—and 17–35% higher—than those obtained by simple counts. In terms of field-time, drone-surveys can be faster than simple counts, but image analyses were highly time consuming. Conclusion Though CMR likely produces superior estimates, it cannot be performed in most cases due to lack of access and knowledge regarding colonies. Drone-based surveys outperformed ground-based simple counts in terms of outcome and this approach is therefore suitable for use across the range of the species. Moreover, the aerial approach is currently the only credible solution for accessing and surveying marine iguanas at highly remote colonies. The application of citizen science and other aids such as machine learning will alleviate the issue regarding time needed to analyze the images.
The aim of this study was to evaluate the anti-MMP activity of two concentrations of copper nanoparticles (CuNp) and the effect of their addition to a universal adhesive system on resin cement-radicular dentin in situ degree of conversion (DC), elastic modulus (EM), nanoleakage (NL), and push-out bond strength (PBS). Anti-MMP activity was evaluated for several MMPs. Seventy-two roots of endodontically prepared human lower premolars were randomly divided into six groups according to CuNp concentration (0% [control], 0.1%, 0.2%) and adhesive strategy (etch-and-rinse [ER] and self-etch [SE]). Fiber posts were cemented, DC was measured using micro-Raman spectroscopy, the EM of the hybrid layer and adhesive layer was measured using a nano-indenter, the NL was evaluated by scanning electron microscopy, and PBS was tested at 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey’s test (α = 0.05). CuNp demonstrated anti-MMP activity (p < 0.01). CuNp containing-adhesives showed significant increased DC (p = 0.01), increased EM in the hybrid layer and adhesive layer (p = 0.001), decreased NL values (p = 0.001), and increased PBS (p = 0.0001). Adhesive strategy was not statistically significant (p > 0.47). Usually, a significant difference among root thirds was observed, except for DC and NL when CuNp 0.2% was evaluated. This is the first in vitro study showing that the incorporation of CuNp in an adhesive is an achievable alternative that can provide anti-MMP activity and improve the mechanical and bonding properties to root canal dentin.
Background Androgenetic alopecia (AGA) affects almost half the population, and several treatments intending to regenerate a normal scalp hair phenotype are used. This is the first study comparing treatment efficacy response and resistance using standardized continuous outcomes. Objective To systematically compare the relative efficacy of treatments used for terminal hair (TH) regrowth in women and men with AGA. Methods A systematic literature review was conducted (from inception to August 11, 2021) to identify randomized, Placebo-controlled trials with ≥ 20 patients and reporting changes in TH density after 24 weeks. Efficacy was analyzed by sex at 12 and 24 weeks using Bayesian network meta-analysis (B-NMA) and compared to frequentist and continuous outcomes profiles. Results The search identified 2,314 unique articles. Ninety-eight were included for full-text review, and 17 articles met the inclusion criteria for data extraction and analyses. Eligible treatments included ALRV5XR, Dutasteride 0.5 mg/day, Finasteride 1 mg/day, low-level laser comb treatment (LLLT), Minoxidil 2% and 5%, Nutrafol, and Viviscal. At 24 weeks, the B-NMA regrowth efficacy in TH/cm ² and significance ( ** ) in women were ALRV5XR: 30.09 ** , LLLT: 16.62 ** , Minoxidil 2%: 12.13 ** , Minoxidil 5%: 10.82 ** , and Nutrafol: 7.32 ** , and in men; ALRV5XR: 21.03 ** , LLLT: 18.75 ** , Dutasteride: 18.37 ** , Viviscal: 13.23, Minoxidil 5%: 13.13 ** , Finasteride: 12.38, and Minoxidil 2%: 10.54. Two distinct TH regrowth response profiles were found; Continuous: ALRV5XR regrowth rates were linear in men and accelerated in women; Resistant: after 12 weeks, LLLT, Nutrafol, and Viviscal regrowth rates attenuated while Dutasteride and Finasteride plateaued; Minoxidil 2% and 5% lost some regrowth. There were no statistical differences for the same treatment between women and men. B-NMA provided more accurate, statistically relevant, and conservative results than the frequentist-NMA. Conclusion Some TH regrowth can be expected from most AGA treatments with less variability in women than men. Responses to drug treatments were rapid, showing strong early efficacy followed by the greatest resistance effects from flatlining to loss of regrowth after 12–16 weeks. Finasteride, Minoxidil 2% and Viviscal in men were not statistically different from Placebo. LLLT appeared more efficacious than pharmaceuticals. The natural product formulation ALRV5XR showed better efficacy in all tested parameters without signs of treatment resistance (see Graphical abstract ). Systematic review registration www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42021268040 , identifier CRD42021268040.
Accurate segmentation of anatomical structures is a critical step for medical image analysis. Deep learning architectures have become the state-of-the-art models for automatic medical image segmentation. However, these models require an extensive labelled dataset to achieve a high performance. Given that obtaining annotated medical datasets is very expensive, in this work we present a two-phase teacher-student approach for semi-supervised learning. In phase 1, a three network U-Net ensemble, denominated the teacher, is trained using the labelled dataset. In phase 2, a student U-Net network is trained with the labelled dataset and the unlabelled dataset with pseudo-labels produced with the teacher network. The student network is then used for inference of the testing images. The proposed approach is evaluated on the task of abdominal segmentation from the FLARE2022 challenge, achieving a mean 0.53 dice, 0.57 NSD, and 44.97 prediction time on the validation set.
Background Sudden Unexpected Infant Deaths (SUID) can occur between 1 month and 1 year of age and are inequitably distributed with a greater burden in populations with numerous health disparities. Modifying the infant sleep environment to promote safe sleep is the most effective risk reduction strategy to reduce SUID. The provision of baby boxes with a mattress and infant supplies has been part of a larger anti-poverty social justice maternity package for decades in Finland. While infant mortality rates have generally improved after the maternity package was introduced, little is known about whether the provision of the baby box increased safe sleep practices. The purpose of the study was to evaluate whether the provision of a Finnish-style baby box reinforced safe infant sleep practice in the home in a low-resource community in Ecuador. Methods In this longitudinal randomized controlled trial all participants received the same safe sleep education in their third trimester of pregnancy ( n = 100). This was followed by randomization into two groups; the control received a diaper bag and newborn gifts, and the intervention group received a baby box and the same gifts at each timepoint. Four infant sleep practices (room sharing, bed sharing/co-sleeping, position, and soft items in the sleep environment) were assessed at 1 month and 1 months post-delivery during a home visit where safe sleep education was also reinforced with both groups. Results Those in the baby box group were 2.5 times more likely to report safe sleep practices compared with mothers in the diaper bag group at 1 month (odds ratio [ OR ] = 2.45 and 95% confidence interval [ CI ]: 1.03–5.86; χ ² = 4.1, p = .043). The group difference was also present at 6-months post-birth: those in the baby box group were 2.9 times more likely to report safe sleep practices compared with those in the diaper bag group ( OR = 2.86 and 95% CI : 1.16–7.05; χ ² = 5.2, p = .022). Conclusions While not all participants used the box regularly, the mothers who received the box were more likely to practice safe sleep at 1 month and 6 months. This suggests the baby box may have served as an important prompt towards safer infant sleep practice. Trial registration (Clinical Trial Registry, per clinicaltrials.gov : not applicable under 42 CFR 11.22(b) as the study Facility Location was not in the United States (took place in Ecuador), does not involve FDA IND or IDE, and does not involve a drug, biological or device product that is manufactured in and exported from the US for study in another country. The University of San Francisco Quito, Research Ethics Committee in Human Beings approved the study, #2017- 127 M. The University of Kentucky Office of Research Integrity also approved the study, IRB # 42965).
Protected area (PA) extent has increased significantly over the last 150 years globally, but it is yet unclear whether progress in expanding coverage has been accompanied by improved performance in ecological representation. Here, we explore temporal trends in the performance of PA networks in representing > 16,000 vertebrate and plant species in tropical Andean countries based on species bioclimatic niche modelling. We use a randomization analysis to assess whether representation gains over time (1937–2015) are the expected consequence of increasing the overall area of the network or the result of better designed networks. We also explore the impact of climate change on protected-area representation based on projected species distributions in 2070. We found that PAs added in the last three to four decades were better at representing species diversity than random additions overall. Threatened species, amphibians and reptiles are the exception. Species representation is projected to decrease across PAs under climate change, although PA expansions over the last decade (2006–2015) better represented species' future bioclimatic niches than did sites selected at random for most evaluated groups. These findings indicate an unbalanced representation across taxa, and raises concern over under-represented groups, including threatened species, and species’ representation under climate change scenarios. However, they also suggest that decisions related to locating protected areas have become more strategic in recent decades and illustrate that indicators tracking representativeness of networks are crucial in PA monitoring frameworks.
Salmonella enterica is one of the most common causes of foodborne diseases. Bacteriophages provide an option to reduce the presence of Salmonella . Here, we describe the isolation of two lytic Salmonella bacteriophages. The complete genomes were annotated and show similarity to that of the lytic phage NBSal001, in the Drexlerviridae family.
Diets enriched in plant-based foods are associated with the maintenance of a good well-being and with the prevention of many non-communicable diseases. The health effects of fruits and vegetables consumption are mainly due to the presence of micronutrients, including vitamins and minerals, and polyphenols, plant secondary metabolites. One of the most important classes of phenolic compounds are anthocyanins, that confer the typical purple-red color to many foods, such as berries, peaches, plums, red onions, purple corn, eggplants, as well as purple carrots, sweet potatoes and red cabbages, among others. This commentary aims to briefly highlight the progress made by science in the last years, focusing on some unexpected aspects related with anthocyanins, such as their bioavailability, their health effects and their relationship with gut microbiota.
Abstract Background Excess weight is increasing worldwide, and in Latin America more than half of the population is excess weight. One of the reasons for this increase has been excessive sitting time. Still, it remains to be seen whether there is an excessive amount of that time in Latin American adults. This study aimed to associate different sitting time cut-off points with the excess weight. Methods Data from the Latin American Study of Nutrition and Health (ELANS), a cross-sectional population-based survey conducted in eight Latin American countries, were used. The excess weight indicators used were body mass index, and waist and neck circumferences. Sitting time was obtained using questionnaires and categorized at different cut-off points. Differences between sitting time categories (
Horchata, a herbal infusion drink from Ecuador containing a mixture of medicinal plants, has been reported to exhibit anti-inflammatory, analgesic, diuretic, and antioxidant activity. The antibacterial activity of each of the plants contained in the horchata mixture has not been fully evaluated. Thus, in this study, we analysed the antibacterial activity of 21 plants used in horchata, collected from the Ecuadorian Andes region, against bacterial strains of clinical importance. The methanolic extract of Cinnamomum sp. showed minimal inhibitory concentration (MIC) values of 250 µg/mL against Staphylococcus aureus ATCC25923 and Methicillin-resistant S. aureus (MRSA), while Pelargonium odoratissimum exhibited a MIC value of 500 µg/mL towards S. aureus ATCC25923. The high-performance liquid chromatography-diode array detector-tandem mass spectrometry (HPLC-DAD-MS/MS) analyses identified in Cinnamomum sp. epicatechin tannins, cinnamaldehyde, and prehelminthosporol molecules, whereas in P. odoratissimum, gallocatechin and epigallocatechin tannins, some flavonoids, and gallic acid and derivatives were identified. Finally, Cinnamomum sp. and P. odoratissimum showed partial inhibition of biofilm formation of S. aureus ATCC25923 and MRSA. Overall, our findings revealed which of the plants used in horchata are responsible for the antibacterial activity attributed to this herbal drink and exhibit the potential for Cinnamomum sp. and P. odoratissimum secondary metabolites to be explored as scaffolds in drug development.
This study aims at qualitatively and quantitatively evaluating the effects of simulated index finger proximal interphalangeal (PIP) joint fusion angles on hand kinematic function and performance. Although arthrodesis of the index finger PIP joint is an effective medical procedure that produces a durable, pain-free, and stable joint, it permanently immobilizes the joint. Twenty healthy subjects performed basic functional hand activities with the index finger PIP joint unconstrained (UC) and constrained to selected angles under surveillance of a motion capture system. Our results indicate differences in perceived difficulty, time performance, and the functional ROM of the hand joints when the index finger PIP joint is UC and constrained to 0, 20, and 40 degrees of flexion. The mean total perceived difficulty scores for all 6 tasks were higher for the PIP at 0 degrees than for the UC condition (p < 0.001) and for the PIP at 40 degrees (p = 0.048). The functional ROM presented a smaller total number of hand joints affected by the PIP at 20 degrees (25 in total) than the PIP at 0 (31 in total) and 40 (27 in total) degrees during execution of all 6 tasks tested. Therefore, the decision on the appropriate index finger PIP angle for arthrodesis may be between 20 and 40 degrees, as globally for all 6 tasks tested, 0 degrees exhibited the worst results regarding perceived difficulty, performance time, and number of joints with affected ROM. Selecting the appropriate angle for arthrodesis should consider a more complete set of functional activities.
The process of ground motion selection and scaling is an integral part of hazard-and risk-consistent seismic demand analysis of structures. Due to the lack of ground motion records that naturally possess high amplitude and intensity, the research community generally relies on scaling the records to match a target hazard intensity level. The scaling factors used are frequently as high as 10. Due to the criticism received in previous research studies, the extent of amplitude scaling and its process has become a matter of debate, and various constraints on the scaling factors have been proposed. The primary argument against unrestricted amplitude scaling is the unrealistic nature of the scaled records and the possible biases caused in the engineering demand parameters (EDPs) of structures. This study presents a framework to utilize machine-learning and statistical techniques for the assessment of ground motion amplitude scaling for nonlin-ear time-history analysis (NTHA) of structures. The framework utilizes Bayesian non-parametric Gaussian process regressions (GPRs) as surrogate models to obtain statistical estimates of EDPs for scaled and unscaled ground motions. The GPR surrogate models are developed based on a large-scale analysis of five steel moment frames (SMFs) using 200 unscaled as-recorded ground motions for ten spectral acceleration levels, ((1)) (ranging from 0 g to maximum considered earthquake, MCE) and 2500 scaled ground motions representing 50 scale factors (), and the 10 (1) levels for each SMF. For each building, two types of EDPs are considered: i) peak inter-story drift ratio (PIDR) and ii) peak floor acceleration (PFA). To provide a better interpretation of the GPR surrogate models, the concept of explainable artificial intelligence (i.e., Shapley additive explanation, SHAP) is used to obtain insights into the decision-making process of the GPR models with respect to the and (1). Then, for the 10 (1) levels, the GPR-based EDP estimates under scaled ground motions corresponding to 50 different SFs are compared with the EDP estimates of unscaled ground motions. The This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. 2 FAYAZ et al. comparison is conducted using Kolmogorov-Smirnov (KS) statistical hypothesis test. Results indicate that the range of allowable s depends on two factors: i) intensity level (characterized by (1)), and ii) the dynamic properties of the building. In general, it is noticed that allowable s range between 0.5 and 3.0 for PIDRs, and from 0.6 to 2.0 for PFAs. Finally, the EDP between the unscaled and scaled ground motions are adhered to various discrepancies observed in different intensity measures representing amplitude-, duration-, energy-, and frequency-content of the two sets of ground motions.
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4,035 members
Fernando Javier Torres
  • Grupo de Química Computacional y Teórica (QCT-USFQ)
Gabriel Trueba
  • Institute of Microbiology
Enrique Teran
  • School of Medicine
Pedro Aponte
  • Department of Biotechnology
Diego de Robles, 170901, Quito, Ecuador
Head of institution
Carlos Montufar
+593 22971700