ANID

Permanent URI for this collection

https://repositorio.uc.cl/handle/11534/74801

Browse

Now showing 1 - 16 of 16

A longitudinal approach for understanding algorithm use
(WILEY, 2022) Chacón Hiriart, Álvaro Marcelo; Kausel, Edgar E.; Reyes Torres Tomas Hernan
Research suggests that algorithms-based on artificial intelligence or linear regression models-make better predictions than humans in a wide range of domains. Several studies have examined the degree to which people use algorithms. However, these studies have been mostly cross-sectional and thus have failed to address the dynamic nature of algorithm use. In the present paper, we examined algorithm use with a novel longitudinal approach outside the lab. Specifically, we conducted two ecological momentary assessment studies in which 401 participants made financial predictions for 18 days in two tasks. Relying on the judge-advisor system framework, we examined how time interacted with advice source (human vs. algorithm) and advisor accuracy to predict advice taking. Our results showed that when the advice was inaccurate, people tended to use algorithm advice less than human advice across the period studied. Inaccurate algorithms were penalized logarithmically; the effect was initially strong but tended to fade over time. This suggests that first impressions are crucial and produce significant changes in advice taking at the beginning of the interaction, which later tends to stabilize as days go by. Therefore, inaccurate algorithms are more likely to accrue a negative reputation than inaccurate humans, even when having the same level of performance.
A simple analytical model for a fast 3D assessment of peripheral photon dose during coplanar isocentric photon radiotherapy
(2022) Sánchez Nieto, Beatriz; López Martínez, Ignacio N.; Rodríguez Mongua, José Luis; Espinoza Bornscheuer, Ignacio Guillermo
Considering that cancer survival rates have been growing and that nearly two-thirds of those survivors were exposed to clinical radiation during its treatment, the study of long-term radiation effects, especially secondary cancer induction, has become increasingly important. To correctly assess this risk, knowing the dose to out-of-field organs is essential. As it has been reported, commercial treatment planning systems do not accurately calculate the dose far away from the border of the field; analytical dose estimation models may help this purpose. In this work, the development and validation of a new three-dimensional (3D) analytical model to assess the photon peripheral dose during radiotherapy is presented. It needs only two treatment-specific input parameter values, plus information about the linac-specific leakage, when available. It is easy to use and generates 3D whole-body dose distributions and, particularly, the dose to out-of-field organs (as dose–volume histograms) outside the 5% isodose for any isocentric treatment using coplanar beams [including intensity modulated radiotherapy and volumetric modulated arc therapy (VMAT)]. The model was configured with the corresponding Monte Carlo simulation of the peripheral absorbed dose for a 6 MV abdomen treatment on the International Comission on Radiological Protection (ICRP) 110 computational phantom. It was then validated with experimental measurements using thermoluminescent dosimeters in the male ATOM anthropomorphic phantom irradiated with a VMAT treatment for prostate cancer. Additionally, its performance was challenged by applying it to a lung radiotherapy treatment very different from the one used for training. The model agreed well with measurements and simulated dose values. A graphical user interface was developed as a first step to making this work more approachable to a daily clinical application.
Association between obesity and atopic dermatitis in children: A case-control study in a high obesity prevalence population
(2022) Iturriaga, Carolina; Bustos, María Francisca; Le Roy, Catalina; Rodríguez, Rocío; Cifuentes, Lorena; Silva-Valenzuela, Sergio; Vera-Kellet, Cristián; Cristi, Francisca; Pérez-Mateluna, Guillermo; Cabalín, Carolina; Hoyos-Bachiloglu, Rodrigo; Camargo Jr., Carlos A.; Borzutzky Schachter, Arturo
Background/Objective: Atopic dermatitis (AD) is a chronic inflammatory skin disease. Research suggests an association between obesity and AD, although evidence is lacking from Latin American populations. This study evaluated the association of obesity with AD in children from Chile, a country with high obesity prevalence. Methods: A case-control study was performed in children with active AD (cases) and healthy controls (HCs) from Santiago, Chile. Body mass index was evaluated by z-score (z-BMI), with overweight defined as z-BMI ≥+1 and <+2, and obesity as z-BMI ≥+2. Abdominal obesity was defined by a waist circumference-to-height ratio (WHR) ≥0.5. AD severity was evaluated by Scoring AD (SCORAD) index. Results: A total of 174 children with AD and 101 controls were included. AD patients had similar overweight (27% vs. 28%) and obesity (21% vs. 26%) rates as HCs (p = .65). Abdominal obesity rates were also comparable (64% vs. 62%, p = .81). In sex-specific analyses, girls with AD had higher abdominal obesity rates than HCs (71% vs. 53%, p < .05) while boys with AD had lower abdominal obesity rates than HCs (53% vs. 75%, p = .03). Among children with AD, higher z-BMI or WHR did not correlate with higher SCORAD, eosinophil counts or total IgE. Conclusion: In our study, Chilean children with AD had high but similar rates of obesity as HCs, but showed sex-specific associations of abdominal obesity and AD. Further research is needed to evaluate these associations and the roles that weight excess and weight loss could play in the pathogenesis and treatment of AD.
Eating contexts determine the efficacy of nutrient warning labels to promote healthy food choices
(Frontiers Media S.A., 2023) Caballero Vivanco, Sara; Moenne Vargas, Cristóbal Matías; Delgado Bravo, Mauricio Antonio; Luarte Rodríguez, Luis Nicolás; Jiménez, Yanireth; Galgani Fuentes, José Eduardo; Perez Leighton, Claudio
Introduction: Unhealthy food choices increase the risk of obesity and its co-morbidities. Nutrition labels are a public health policy that aims to drive individuals toward healthier food choices. Chile has been an example of this policy, where mandatory nutrient warning labels (NWL) identify processed foods high in calories and critical nutrients. Eating contexts influence individual food choices, but whether eating contexts also influence how NWL alter the decision process and selection during food choice is unknown. Methods: In an online mouse-tracking study, participants prompted to health, typical, or unrestricted eating contexts were instructed to choose between pairs of foods in the presence or absence of NWL. Conflict during choices was analyzed using mouse paths and reaction times. Results: NWL increased conflict during unhealthy food choices and reduced conflict during healthy choices in all contexts. However, the probability that NWL reversed an unhealthy choice was 80% in a healthy, 37% in a typical, and 19% in an unrestricted context. A drift-diffusion model analysis showed the effects of NWL on choice were associated with an increased bias toward healthier foods in the healthy and typical but not in the unrestricted context. Discussion: These data suggest that the efficacy of NWL to drive healthy food choices increases in a healthy eating context, whereas NWL are less effective in typical or unrestricted eating contexts.
Estudio biomecánico de una prótesis de rodilla mediante simulación utilizando elementos finitos
(2023) Cortés Marchetti, Fernanda Javiera; Ramos Grez, Jorge; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
Esta investigación se enfoca en el estudio del comportamiento mecánico de la articulación de la rodilla cuando se reemplaza con una articulación artificial. El objetivo es comprender y determinar qué factores influyen en la adhesión, desplazamiento y concentración de tensiones entre el hueso y la prótesis, con el fin de evitar complicaciones como el aflojamiento. Para lograr esto, se investiga el efecto de diversos parámetros, como el coeficiente de fricción, los materiales de la prótesis utilizados y el peso del paciente, en las características biomecánicas de una prótesis de rodilla. Se realizó una simulación computacional utilizando elementos finitos para evaluar los parámetros mencionados. Se utilizaron diferentes softwares para generar modelos 3D de la articulación tibiofemoral sujeto-específica, a la cual se le asignaron las propiedades ortotrópicas del tejido óseo, e isotrópicas al material de la prótesis. Una vez que se tuvo el modelo de la articulación, se aplicó una fuerza compresiva de 735N y se realizaron varias simulaciones en las que se varió el coeficiente de roce entre 0.08 y 1, se varió el material del componente cojín plástico (PE, MDPE, HDPE y UHMWPE) y se analizó la resistencia mecánica a la fatiga en la interfaz entre el hueso y el implante. Al analizar los resultados obtenidos, se observa que un aumento en el coeficiente de roce puede generar una mayor adhesión a largo plazo en la prótesis, ya que los esfuerzos se reducen, la presión de contacto aumenta y se incrementa el ciclo de vida de la prótesis. En cuanto al material del cojín, el polietileno mostró mejores características, ya que presentaba un menor desplazamiento entre el componente plástico y el componente femoral. No obstante, las diferencias entre los materiales no fueron significativas.
Eucryphia cordifolia extracts: Phytochemical screening, antibacterial and antioxidant activities
(2021) Viteri, Rafael; Giordano, Ady; Montenegro, Gloria; Zacconi, Flavia C. M.
Eucryphia cordifolia is a native and dominant species from the Temperate Forest in the southern region of Chile. It is a crucial melliferous species producing unifloral honey with outstanding antibacterial properties with great commercial value at international markets. A phytochemical screening was developed by colorimetric and gravimetric methods. Antioxidant activities were assessed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric ion reducing antioxidant power (FRAP) method. The minimum bactericidal concentration (MBC) was the method used to determine the antibacterial activity. The results revealed the highest antioxidant activity for the methanolic extracts of branches (IC50 35.7 mu g/mL for DPPH, IC50 11.0 mu g/mL for ABTS, and 4.6 mM FeSO4 center dot 7H(2)O/g in FRAP), attributed to its high content of total phenols (332.8 mg GAE/g). The quantification of the MBC led to values in the range of 0.78-12.5 mg/mL for S. aureus and S. pyogenes, and 6.25-50 mg/mL for E. coli and P. aeruginosa, respectively. The presented work provides valuable first in vitro evidence regarding the potential application of E. cordifolia extracts as antioxidants and antibacterial agents in the nutraceutical and phytopharmaceutical industry.
Green by Design: Convergent Synthesis, Computational Analyses, and Activity Evaluation of New FXa Inhibitors Bearing Peptide Triazole Linking Units
(2022) Rodriguez, Diego F.; Duran Osorio, Francisca; Duarte, Yorley; Olivares, Pedro; Moglie, Yanina; Dua, Kamal; Zacconi, Flavia C. M.
Green chemistry implementation has led to promising results in waste reduction in the pharmaceutical industry. However, the early sustainable development of pharmaceutically active compounds and ingredients remains a considerable challenge. Herein, we wish to report a green synthesis of new pharmaceutically active peptide triazoles as potent factor Xa inhibitors, an important drug target associated with the treatment of diverse cardiovascular diseases. The new inhibitors were synthesized in three steps, featuring cycloaddition reactions (high atom economy), microwave-assisted organic synthesis (energy efficiency), and copper nanoparticle catalysis, thus featuring Earth-abundant metals. The molecules obtained showed FXa inhibition, with IC50-values as low as 17.2 mu M and no associated cytotoxicity in HEK293 and HeLa cells. These results showcase the environmental potential and chemical implications of the applied methodologies for the development of new molecules with pharmacological potential.
Hertoghe’s sign in atopic dermatitis
(2020) Borzutzky Schachter, Arturo; Tejos-Bravo, Macarena; Venegas, Luis F.; Iturriaga, Carolina
Internet Addiction of Older Women and Its Relationship With Social Influence and Social Networks Use as a Mediator
(2022) Rosell Cisternas, Javiera; Leeson, George W.; Verges, Alvaro
The aim is to analyse the relationship between social influence for Internet use and Internet addiction (IA) in older women, considering the use of Internet-based social networks as a mediator. The participants were 480 older women Internet users. Social influence, frequency of use of social networks and IA (including loss of control and emotional dysregulation) were evaluated. Structural Equation Modeling (SEM) was conducted to analyse the proposed model. The use of social networks was a significant mediator in the relationship between social influence for Internet use and the dimension of loss of control of IA. On the contrary, social network use was not a significant mediator. Older women with more social influence reported more frequency of social networking and, in turn, more loss of control in Internet use. Public policy and clinicians should address addictive behaviours about Internet use in older women, preventing the negative consequences.
Mechanical characterization of the emphysematous rat lung
(2023) Villa Barros, Benjamín; Hurtado Sepúlveda, Daniel; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
Los modelos animales han sido utilizados ampliamente para evaluar el irreversible crecimiento de los espacios aéreos alveolares y comprender la fisiopatología del enfisema. Mientras que la respuesta mecánica pulmonar a estos cambios morfológicos ha sido documentada en la literatura, la caracterización mecánica del tejido enfisematoso ha sido poco investigada hasta la fecha. En este trabajo, estudiamos la respuesta mecánica del tejido y las características morfológicas alveolares de los pulmones a partir de un modelo animal de enfisema inducido por elastasa. Analizamos el comportamiento no lineal del tejido utilizando modelos constitutivos hiperelásticos adecuados a partir de los cuales caracterizamos los parámetros del material. Analizamos más a fondo el efecto de la dosis de elastasa en las propiedades estructurales y materiales y estudiamos su conexión con la compliance respiratoria. En particular, mostramos que si bien la compliance pulmonar en los grupos inducidos por elastasa no difiere del grupo de Control, existen diferencias significativas en el comportamiento mecánico y la morfometría del tejido. Además, nuestros resultados sugieren que durante el desarrollo temprano del enfisema, los parámetros del material tisular son más sensibles al agrandamiento alveolar que a la compliance pulmonar. Nuestros hallazgos resaltan la importancia de evaluar la mecánica tisular en los pulmones enfisematosos, ya que los parámetros materiales pueden representar un indicador prometedor para detectar el inicio de la remodelación del enfisema durante las primeras etapas de la enfermedad.
nAChR-induced octopamine release mediates the effect of nicotine on a startle response in Drosophila melanogaster
(2013) Fuenzalida Uribe, Nicolás Leonardo; Meza Cárdenas, Rodrigo Alexis; Hoffmann, Hernán A.; Varas Orozco, Rodrigo; Campusano Astorga, Jorge Mauricio
Biogenic amines (BAs) play a central role in the generation of complex behaviors in vertebrates and invertebrates, including the fly Drosophila melanogaster. The comparative advantages of Drosophila as a genetic model to study the contribution of BAs to behaviors stumble upon the difficulty to access the fly brain to ask relevant physiological questions. For instance, it is not known whether the activation of nicotinic acetylcholine receptors (nAChRs) induces the release of BAs in fly brain, a phenomenon associated to several behaviors in vertebrates. Here, we describe a new preparation to study the efflux of BAs in the adult fly brain by in vitro chronoamperometry. Using this preparation we show that nAChR agonists including nicotine induce a fast, transient, dose-dependent efflux of endogenous BAs, an effect mediated by -bungarotoxin-sensitive nAChRs. By using different genetic tools we demonstrate that the BA whose efflux is induced by nAChR activation is octopamine (Oct). Furthermore, we show that the impairment of a mechanically induced startle response after nicotine exposure is not observed in flies deficient in Oct transmission. Thus, our data show that the efflux of BAs in Drosophila brain is increased by nAChR activation as in vertebrates, and that then AChR-induced Oct release could have implications in a nicotine-induced behavioral response.
Refractory systemic juvenile idiopathic arthritis successfully treated with rapamycin
(Oxford University Press, 2021) Concha, Sara; Rey-Jurado, Emma; Poli, M. Cecilia; Hoyos-Bachiloglu, Rodrigo
School environments and obesity: a systematic review of interventions and policies among school-age students in Latin America and the Caribbean
(Springer Nature, 2022) Vega Salas, María Jesús; Murray, Claudia; Nunes, Richard; Hidalgo-Arestegui, Alessandra; Curi-Quinto, Katherine; Penny, Mary E.; Cueto, Santiago; Lovegrove, Julie Anne; Sánchez, Alan; Vimaleswaran, Karani Santhanakrishnan
Background: The rapid rise in obesity rates among school children in Latin America and the Caribbean (LAC) could have a direct impact on the region’s physical and mental health, disability, and mortality. This review presents the available interventions likely to reduce, mitigate and/or prevent obesity among school children in LAC by modifying the food and built environments within and around schools. Methods: Two independent reviewers searched five databases: MEDLINE, Web of Science, Cochrane Library, Scopus and Latin American and Caribbean Health Sciences Literature for peer-reviewed literature published from 1 January 2000 to September 2021; searching and screening prospective studies published in English, Spanish and Portuguese. This was followed by data extraction and quality assessment using the Cochrane risk-of-bias tool (RoB 2) and the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I), adopting also the PRISMA 2020 guidelines. Due to the heterogeneity of the intervention’s characteristics and obesity-related measurements across studies, a narrative synthesis was conducted. Results: A total of 1342 research papers were screened, and 9 studies were included; 4 in Mexico, and 1 each in Argentina, Brazil, Chile, Colombia, and Ecuador. Four studies reported strategies for modifying food provision; four other targeted the built environment, (modifying school premises and providing materials for physical activity); a final study included both food and built environment intervention components. Overall, two studies reported that the intervention was significantly associated with a lower increase over time in BMI/obesity in the intervention against the control group. The remaining studies were non-significant. Conclusions: Data suggest that school environmental interventions, complementing nutritional and physical education can contribute to reduce incremental childhood obesity trends. However, evidence of the extent to which food and built environment components factor into obesogenic environments, within and around school grounds is inconclusive. Insufficient data hindered any urban/rural comparisons. Further school environmental intervention studies to inform policies for preventing/reducing childhood obesity in LAC are needed.
Shared Components of Worldwide Successful Sexuality Education Interventions for Adolescents: A Systematic Review of Randomized Trials
(2023) Torres Cortés, Betzabé Carolina; Leiva, Loreto; Canenguez, Katia; Olhaberry Huber, Marcia; Méndez Hernández, Emmanuel Joshua
A crucial aspect of human development is sexuality which has implications for health, particularly in adolescence, since unfavorable sexual experiences may result in physical and mental problems. Sexuality education interventions (SEI) are one of the most used actions to promote sexual health in adolescents. Nevertheless, there is variability across their components; therefore, key elements for an effective SEI targeted at adolescents (A-SEI) are not well known. Based on this background, this study aims to identify the shared components of successful A-SEI through a systematic review of randomized controlled trials (RCT). This study followed the preferred reporting items for systematic reviews and meta-analyses statement. A search was conducted in CINAHL, PsycInfo, PubMed, and Web of Science between November and December 2021. A total of 21 studies passed the inclusion test after the review of 8318 reports. A total of 18 A-SEIs were identified in these studies. The components analyzed were the intervention’s approach, dose, type of intervention, theoretical framework, facilitators’ training, and intervention methodology. The results established that components that should be present in the design of an effective A-SEI are behavior change theoretical models, the use of participatory methodology, be targeted at mixed-sex groups, facilitators’ training, and at least ten hours of weekly intervention.
The asthma predictive index as a surrogate diagnostic tool in preschoolers: Analysis of a longitudinal birth cohort
(WILEY, 2021) Castro Rodriguez, Jose A.; Forno, Erick; Padilla, Oslando; Casanello, Paola; Krause, Bernardo J.; Borzutzky Schachter, Arturo
Diagnosing asthma in preschool children remains an unsolved challenge, at a time when early identification would allow for better education and treatment to prevent morbidity and lung function deterioration. Objective To evaluate if the asthma predictive index (API) can be used as surrogate for asthma diagnosis in preschoolers. Methods Birth cohort of 339 pregnant women enrolled at delivery and their offspring, who were followed for atopy, wheezing, and other respiratory illnesses through 30 months of age. The API was determined at 30 months of age by the researchers; and examined its association with physician-diagnosed asthma during the first 30 months, made independently by the primary care physician not involved in the study. Results Among 307 offspring with complete follow-up, 44 (14.3%) were API+. Maternal body mass index, maternal education, past oral contraceptive use, birthweight, placenta weight, age of daycare at 12 m, gastroesophageal reflux disease at 12 m, acute otitis media at 18 m, bronchiolitis, croup and pneumonia, cord blood adiponectin were all associated with API+. In the multivariable analysis, API+ was associated with almost sixfold odds of asthma diagnosis (adjusted OR = 5.7, 95% CI [2.6-12.3]), after adjusting for the relevant covariates above including respiratory infections like bronchiolitis and pneumonia. The API sensitivity was 48%, specificity 92%, 61% PPV, 88% NPV, 6.4 LR+, 0.56 LR-, 0.84 diagnosis accuracy. The adjusted odds for asthma was 11.4. Conclusions This longitudinal birth cohort suggests, for first time, that API (a structured definition for asthma), could be used as a diagnostic tool, not only as a prognostic tool, in toddlers and preschoolers.
The Human Dermis as a Target of Nanoparticles for Treating Skin Conditions
(2023) Salazar Muñoz, Javier Alonso; Carmona, Thais; Zacconi, Flavia C. M.; Venegas Yazigi, Diego; Cabello Verrugio, Claudio; Il Choi, Won; Vilos, Cristian
Skin has a preventive role against any damage raised by harmful microorganisms and physical and chemical assaults from the external environment that could affect the body’s internal organs. Dermis represents the main section of the skin, and its contribution to skin physiology is critical due to its diverse cellularity, vasculature, and release of molecular mediators involved in the extracellular matrix maintenance and modulation of the immune response. Skin structure and complexity limit the transport of substances, promoting the study of different types of nanoparticles that penetrate the skin layers under different mechanisms intended for skin illness treatments and dermo-cosmetic applications. In this work, we present a detailed morphological description of the dermis in terms of its structures and resident cells. Furthermore, we analyze the role of the dermis in regulating skin homeostasis and its alterations in pathophysiological conditions, highlighting its potential as a therapeutic target. Additionally, we describe the use of nanoparticles for skin illness treatments focused on dermis release and promote the use of metal-organic frameworks (MOFs) as an integrative strategy for skin treatments.

Browse

Browsing ANID by browse.metadata.categoriaods "03 Salud y bienestar"

Results Per Page

Sort Options