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Actividad enzimática de glutatión peroxidasa en equinos pura raza chilena en actividad de entrenamiento
No full textMedicina Veterinaria, Licenciado en Medicina VeterinariasLa enzima glutatión peroxidasa (GPx) es la enzima encargada de proteger al organismo del daño oxidativo destruyendo los peróxidos, superóxidos y radicales hidroxílicos,
nocivos para la integridad celular y producidos durante el ejercicio. La actividad de esta enzima GPx se relaciona directamente con las concentraciones de selenio (Se) en sangre, ya que este oligoelemento forma parte de su estructura molecular, teniendo esta enzima 4 átomos de Se en su estructura. En Chile existe poca información acerca de las concentraciones sanguíneas de Se y como estas se relacionan con el estrés oxidativo de los equinos atletas de una forma correcta y si la actividad enzimática de GPx varía significativamente en equinos de distintas edades e intensidades de entrenamiento. Este estudio experimental propone determinar si hay variación en la actividad enzimática sanguínea de GPx en equinos pura raza chilena de distintas edades y que se encuentren en distintos niveles de entrenamiento para rodeo. Para ello se mide la actividad de GPx sanguínea en tres grupos de equinos (n=30) divididos por nivel de entrenamiento (ligero, medio e intenso) y edad (6 a 12 años y 13 a 17 años). Los resultados señalan una actividad promedio de 95,8 U/gHb para entrenamiento ligero, 53,5 U/gHb entrenamiento medio y 119,7 U/gHb en el caso de entrenamiento severo (p>0,05). En relación con la edad, los valores promedios son para el rango de 6 a 12 años de 100,3 U/gHb, y de 96,0 para el rango de 13 a 17 años (p>0,05).
Se concluye que la actividad de GPx no se ve influenciada por la intensidad del ejercicio ni por la edad de los caballos pura raza chilena que practican rodeo chileno, por lo que se acepta la hipótesis nula de este estudio.The enzyme glutathione peroxidase (GPx) is the enzyme responsible for protecting the body from oxidative damage by destroying peroxides, superoxides and hydroxyl radicals, which are harmful to cellular integrity and produced during exercise. The activity of this GPx enzyme is directly related to the concentrations of selenium (Se) in the blood, since this trace element is part of its molecular structure, with this enzyme having 4 Se atoms in its structure. In Chile, there is little information about blood concentrations of Se and how these relate to the oxidative stress of equine athletes correctly and whether the enzymatic activity of GPx varies significantly in horses of different ages and training intensities.
This experimental study is conducted to determine if there is variation in the blood enzymatic activity of GPx in purebred Chilean horses of different ages and that are at different levels of rodeo training. For this purpose, the blood GPx activity is measured in three groups of horses (n=30) divided by training level (light, medium and intense) and age (6 to 12 years and 13 to 17 years). The results indicate an average activity of 95.8 U/gHb for light training, 53.5 U/gHb for medium training and 119.7 U/gHb in the case of severe training (p>0.05). In relation to age, the average values are 100.3 U/gHb for the range from 6 to 12 years, and 96.0 for the range from 13 to 17 years (p>0.05).
It is concluded that GPx activity is not influenced by exercise intensity or age of Chilean purebred horses that practice Chilean rodeo, Therefore, the null hypothesis of this study is accepted
Regulatory T cells administration reduces anxiety-like behavior in mice submitted to chronic restraint stress
No full textPublisher Copyright: Copyright © 2024 Cepeda, Elizondo-Vega, Garrido, Tobar, Araneda, Oliveros, Ordenes, Carril, Vidal, Luz-Crawford, García-Robles and Oyarce.Background: Major depression disorder (MDD) and anxiety are common mental disorders that significantly affect the quality of life of those who suffer from them, altering the person’s normal functioning. From the biological perspective, the most classical hypothesis explaining their occurrence relies on neurotransmission and hippocampal excitability alterations. However, around 30% of MDD patients do not respond to medication targeting these processes. Over the last decade, the involvement of inflammatory responses in depression and anxiety pathogenesis has been strongly acknowledged, opening the possibility of tackling these disorders from an immunological point of view. In this context, regulatory T cells (Treg cells), which naturally maintain immune homeostasis by suppressing inflammation could be promising candidates for their therapeutic use in mental disorders. Methods: To test this hypothesis, C57BL/6 adult male mice were submitted to classical stress protocols to induce depressive and anxiety-like behavior; chronic restriction stress (CRS), and chronic unpredictable stress (CUS). Some of the stressed mice received a single adoptive transfer of Treg cells during stress protocols. Mouse behavior was analyzed through the open field (OFT) and forced swim test (FST). Blood and spleen samples were collected for T cell analysis using cell cytometry, while brains were collected to study changes in microglia by immunohistochemistry. Results: Mice submitted to CRS and CUS develop anxiety and depressive-like behavior, and only CRS mice exhibit lower frequencies of circulating Treg cells. Adoptive transfer of Treg cells decreased anxiety-like behavior in the OFT only in CRS model, but not depressive behavior in FST in neither of the two models. In CRS mice, Treg cells administration lowered the number of microglia in the hippocampus, which increased due this stress paradigm, and restored its arborization. However, in CUS mice, Treg cells administration increased microglia number with no significant effect on their arborization. Conclusion: Our results for effector CD4+ T cells in the spleen and microglia number and morphology in the hippocampus add new evidence in favor of the participation of inflammatory responses in the development of depressive and anxiety-like behavior and suggest that the modulation of key immune cells such as Treg cells, could have beneficial effects on these disorders
Detección molecular de material genético del virus causante de gripe aviar en fecas de lobos marinos obtenidas desde el mercado de Angelmó Puerto Montt
No full textLa influenza aviar H5N1 es una enfermedad infecciosa que forma parte de la familia
Orthomyxoviridae, esta afecta principalmente aves y mamíferos marinos. H5N1 fue
identificada por primera vez el año 1996 en Hong Kong, sin embargo, en 2022 casos
incrementaron exponencialmente, esparciéndose por gran parte del planeta, generando
gran preocupación en la salud pública, por su propiedad zoonotica e interés en la salud
animal por su alta mortalidad. Chile no ha sido la excepción, H5N1 ha sido detectada en
animales en las 16 regiones del país, obteniendo un pick de contagios el año 2023.
Dentro de las especies marinas afectadas se encuentra el Lobo Marino (Otaria
flavescens), esta especie figura como la principal damnificada en número de contagios
e individuos fallecidos. Este mamífero marino es caracterizado por habitar en las costas
de todo el largo del país principalmente en litorales que les proporcionen una fuente de
alimento, descanso y refugio. Así mismo, estos conviven a la cercanía de humanos,
principalmente trabajadores del área marítima, tales como, pescadores, recolectores de
mariscos y comerciantes de los productos del mar. En este estudio nos enfocamos en el
mercado de Angelmó de Puerto Montt, sitio donde existe interacción constantemente
entre el lobo marino y el humano. En este lugar se realizaron tomas de muestras de
heces de lobos marinos entre abril y marzo del 2024 de tipo ambiental, con el fin de
identificar H5N1 en ellas. Muestras analizadas fueron 24 en total, las cuales, se
realizaron pruebas de extracción de ARN y pruebas de PCRr. Resultados de PCR en su
totalidad catalogaron como negativas de la presencia del virus. Se sugiere realizar
muestreos de forma activa, puesto que no podríamos tildar Angelmó libre de H5N1 con
el número total de muestras analizadas, más bien, muestras estudiadas ser
catalogadas como exentas de H5N1.Avian influenza H5N1 is an infectious disease that is part of the Orthomyxoviridae family,
which mainly affects birds and marine mammals. H5N1 was identified for the first time in
1996 in Hong Kong, however, in 2022 cases increased exponentially, spreading
throughout most of the planet, generating great concern in public health, due to its
zoonotic properties and interest in animal health because of its high mortality. Chile has
not been the exception, H5N1 has been detected in animals in the 16 regions of the
country, obtaining a pick of contagions in the year 2023. Among the affected marine
species is the sea lion (Otaria flavescens), this species is the main victim in terms of
number of infections and deaths. This marine mammal is characterized by inhabiting the
coasts of the entire length of the country, mainly on coastlines that provide them with a
source of food, rest and shelter. They also live in close proximity to humans, mainly
workers in the maritime area, such as fishermen, shellfish gatherers and seafood
traders. In this study we focused on the Angelmó market in Puerto Montt, a place where
there is constant interaction between sea lions and humans. At this site, environmental
samples of sea lion feces were taken between April and March 2024, in order to identify
H5N1 in them. A total of 24 samples were analyzed and RNA extraction and PCRr tests
were performed. All PCR results were negative for the presence of the virus. It is
suggested to perform active sampling, since we could not label Angelmó free of H5N1
with the total number of samples analyzed, rather, samples studied would be catalogued
as free of H5N1
Seismic evaluation of Site-City interaction effects between city blocks
No full textPublisher Copyright: Copyright © 2024 Vicencio and Alexander.In urban environments, buildings are often seismically designed with their standalone response, such as isolated structures devoid of surrounding structures. Nonetheless, there is always a chance that a significant seismic interaction between nearby buildings through the underlying soil will occur in big urban areas with high building densities. This paper evaluates the Site-City interaction (SCI) between different city block arrangements under seismic excitation given different parameters of the buildings and centre-to-centre interbuilding distances. A database of strong ground motion records with Far-Field, Near-Field Without Pulse and Near-Field Pulse-Like characteristics are employed. The results suggest that the SCI effects were strongly influenced by the building properties and resonance effects of the soil stratum. Furthermore, as a mean for all the earthquakes considered here, the SCI can amplify or reduce the seismic response of the buildings, depending on the relative position between the city blocks
Hybrid DMS-ZVS-PWM With In-Depth Mathematical Model for Boosting Efficiency of Grid-Connected SEPIC Differential Mode Inverter
No full textPublisher Copyright: AuthorsSingle-stage differential mode inverters (DMI) have been extensively utilized in three-phase grid-connected systems due to several advantages, such as few semiconductor devices resulting from their simple and modular configuration. Nevertheless, the modulation and control strategy require further enhancement to enable more efficient power conversion across various operations. Therefore, this paper introduces a detailed analytical model of the SEPIC-DMI, leading to the development of a hybrid discontinuous modulation scheme pulse width modulation (DMS-PWM), which incorporates zero voltage switching (ZVS), denoted as Hybrid DMS-ZVS-PWM approach. In the proposed strategy, the duty cycle of SEPIC-DMI is zero for one-third of the grid frequency cycle, which leads to minimizing conduction and switching power losses. Moreover, the voltage stress on the components is significantly reduced due to DMS-PWM. For ZVS, a simplified active-clamp circuit is proposed and designated using a single switch and two small capacitors. The proposed active-clamp circuit is integrated into the SEPIC-DMI to verify SEPIC power switches’ ZVS and zero current switching (ZCS). The ZVS/ZCS improves the inverter efficiency by major minimization in power losses. The mathematical derivations and performance measurements (simulation and experiment) are provided to show the superiority of the proposed hybrid DMS-ZVS-PWM method. The peak efficiency of SEPIC-DMI is enhanced from 90% to 94%, and the voltage stress is curtailed in all components with 13%.Single-stage differential mode inverters (DMI) have been extensively utilized in three-phase grid-connected systems due to several advantages, such as few semiconductor devices resulting from their simple and modular configuration. Nevertheless, the modulation and control strategy require further enhancement to enable more efficient power conversion across various operations. Therefore, this paper introduces a detailed analytical model of the SEPIC-DMI, leading to the development of a hybrid discontinuous modulation scheme pulse width modulation (DMS-PWM), which incorporates zero voltage switching (ZVS), denoted as Hybrid DMS-ZVS-PWM approach. In the proposed strategy, the duty cycle of SEPIC-DMI is zero for one-third of the grid frequency cycle, which leads to minimizing conduction and switching power losses. Moreover, the voltage stress on the components is significantly reduced due to DMS-PWM. For ZVS, a simplified active-clamp circuit is proposed and designated using a single switch and two small capacitors. The proposed active-clamp circuit is integrated into the SEPIC-DMI to verify SEPIC power switches’ ZVS and zero current switching (ZCS). The ZVS/ZCS improves the inverter efficiency by major minimization in power losses. The mathematical derivations and performance measurements (simulation and experiment) are provided to show the superiority of the proposed hybrid DMS-ZVS-PWM method. The peak efficiency of SEPIC-DMI is enhanced from 90% to 94%, and the voltage stress is curtailed in all components with 13%
Temperature fluctuations in a relativistic gas : Pressure corrections and possible consequences in the deconfinement transition
No full textPublisher Copyright: © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.In this work, we study the effects of random temperature fluctuations on the partition function of a quantum system by means of the replica method. This picture provides a conceptual model for a quantum nonequilibrium system, depicted as an ensemble of subsystems at different temperatures, randomly distributed with respect to a given mean value. We then assume the temperature displays stochastic fluctuations T=T0+δT with respect to its ensemble average value T0, with zero mean δT¯=0 and standard deviation δT2¯=Δ. By means of the replica method, we obtain the average grand canonical potential, leading to the equation of state and the corresponding excess pressure caused by these fluctuations with respect to the equilibrium system at a uniform temperature. Our findings reveal an increase in pressure as the system's ensemble average temperature T0 rises, consistently exceeding the pressure observed in an equilibrium state. We applied our general formalism to three paradigmatic physical systems; the relativistic Fermi gas, the ideal gas of photons, and a gas of non-Abelian gauge fields (gluons) in the noninteracting limit. Finally, we explore the implications for the deconfinement transition in the context of the simple bag model, where we show that the critical temperature decreases
Unraveling the Role of JMJD1B in Genome Stability and the Malignancy of Melanomas
No full textPublisher Copyright: © 2024 by the authors.Genome instability relies on preserving the chromatin structure, with any histone imbalances threating DNA integrity. Histone synthesis occurs in the cytoplasm, followed by a maturation process before their nuclear translocation. This maturation involves protein folding and the establishment of post-translational modifications. Disruptions in this pathway hinder chromatin assembly and contribute to genome instability. JMJD1B, a histone demethylase, not only regulates gene expression but also ensures a proper supply of histones H3 and H4 for the chromatin assembly. Reduced JMJD1B levels lead to the cytoplasmic accumulation of histones, causing defects in the chromatin assembly and resulting in DNA damage. To investigate the role of JMJD1B in regulating genome stability and the malignancy of melanoma tumors, we used a JMJD1B/KDM3B knockout in B16F10 mouse melanoma cells to perform tumorigenic and genome instability assays. Additionally, we analyzed the transcriptomic data of human cutaneous melanoma tumors. Our results show the enhanced tumorigenic properties of JMJD1B knockout melanoma cells both in vitro and in vivo. The γH2AX staining, Micrococcal Nuclease sensitivity, and comet assays demonstrated increased DNA damage and genome instability. The JMJD1B expression in human melanoma tumors correlates with a lower mutational burden and fewer oncogenic driver mutations. Our findings highlight JMJD1B’s role in maintaining genome integrity by ensuring a proper histone supply to the nucleus, expanding its function beyond gene expression regulation. JMJD1B emerges as a crucial player in preserving genome stability and the development of melanoma, with a potential role as a safeguard against oncogenic mutations
Decoding subcontinental lithosphere processes : The key role of fractional crystallization in Central Andes monogenetic volcanism - Insight from El Negrillar volcanic field, Chile
No full textPublisher Copyright: © 2023 The AuthorsSubduction zones are complex geodynamic settings in which volcanic arcs form due to the interaction between subducting slabs, water, and continental materials. Investigating this extensive Earth recycling system offers valuable insights into the exchange of materials between the crust and mantle. While previous research has primarily focused on analyzing polygenetic volcanoes to explore this interaction, monogenetic volcanic fields (MVF) present an opportunity to delve into the mechanisms operating within the upper and lower mantle. Monogenetic volcanoes are a class of volcanoes that are typically smaller in size but showcase a range of eruptive styles and compositions. These volcanoes can be found in various locations along the arc, including the main Central Volcanic Zone (CVZ) (arc-front volcanoes), and even far from the tectonic plate boundaries in the back-arc region (intraplate volcanism). We carried out a detailed geochemical study of El Negrillar (EN) MVF, located in the Central Andes main-arc, on the Altiplano-Puna Plateau's southwestern border. The volcanic field has 35 eruptive centers and a total of 86 eruptive phases originating from its three clusters: Northern, Central, and Southern. EN magmas range in composition from basaltic andesite to dacite and have produced over 6.8 km3 (DRE) of lava and pyroclastic material, which makes it the most voluminous volcanic field in the Central Andes, and therefore, an excellent example to study MVF in arc-systems. We have conducted an extensive study encompassing major and trace elements, as well as isotopic analysis using whole rock Sr-Nd-Pb. We also present an analysis of our results with available geochemical data from the back-arc and main-arc volcanoes, including other monogenetic volcanoes near EN (6 ppm), Ba/Th (>100 ppm), high 143Nd/144Nd > 0.51240, and La/Yb ratios at a given La/Sm compared to the main-arc polygenetic volcanoes. Interestingly, EN also exhibits adakite-like signatures with increasing SiO2 content (high Sr > 600 ppm, Sr/Y > 40, and high La/Yb > 20), a term used for igneous rock suites with chemical characteristics that are identical to those of adakites but produced through petrogenetic processes that do not include a slab component. We explore how fractional crystallization and crustal assimilation participate in the development of monogenetic volcanoes, and our findings underscore the significant influence of fractional crystallization on the monogenetic volcanic processes in the Salar de Atacama region. The geochemical changes observed in this area can be attributed to a combination of varying degrees of fractional crystallization within magmas generated through the partial melting of a garnet-enriched environment, which could be primary lower crust or partial melting of a peridotite mantle that has later equilibrated with garnet-bearing crustal melts
El Reto de la Educación Inclusiva Intercultural en Chile
No full textLa educación inclusiva intercultural nos desafía día a día y más aún, con el acelerado flujo migratorio que se vive a nivel mundial como en Chile. Una de las preocupaciones que tiene la comunidad educativa, es como enfrentar los requerimientos de una educación inclusiva intercultural, para dar cumplimiento a lo establecido en la política pública en coexistencia con la rigidez curricular que existe a nivel país. La falta de coherencia entre lo declarado en las medidas regulatorias y la praxis, dan paso a un gran reto. El propósito del trabajo fue conocer el estado actual en Chile, en cuanto a la implementación de la educación inclusiva intercultural, a nivel curricular, en el sistema escolar. Se aplicó una metodología descriptiva, en base a un análisis documental, es decir, revisión de fuentes disponibles en la red, de los últimos cinco años. Es posible concluir que, existe una discrepancia entre lo indicado en la política pública en relación con la educación inclusiva intercultural y lo que sucede en el aula escolar. Y al mismo tiempo, la rigidez curricular conlleva a un proceso de enseñanza y aprendizaje monocultural, asimilista y hegemónico, que va contra la inclusión y que se asocia a la exclusión. Asimismo, la formación del profesorado cobra importancia, ya que si no tiene las competencias para llevar a cabo la implementación en el aula de manera inclusiva e intercultural, será complejo poder llevar a cabo la política pública y a su vez, cumplir con el ODS 4 de aquí al año 2030
Resiliencia en adolescentes infractores con trayectorias en los sistemas chilenos de bienestar infantil y de justicia adolescente.
No full textEste artículo tiene como objetivo analizar los procesos de significación de la resiliencia en adolescentes que han pasado por los sistemas chilenos de bienestar infantil y de justicia adolescente, dado que son fundamentales para identificar los aspectos que puedan favorecer la adaptación e integración social. A partir de una investigación cualitativa, orientada y fundamentada desde un enfoque fenomenológico, se analizaron seis entrevistas semiestructuradas en profundidad con adolescentes con trayectorias en ambos sistemas. Los resultados destacan que la resiliencia personal de los adolescentes está vinculada a la apreciación que tienen de sí mismos y a los procesos de aprendizaje para el desarrollo de habilidades sociales y de regulación emocional. Por otro lado, la resiliencia social e institucional se caracteriza por la percepción que tienen los adolescentes sobre las mejoras en su calidad de vida y su capacidad de adaptación social. Ellos consideran que es esencial tener relaciones sólidas, confiables y duraderas con consejeros y educadores, y destacan el apoyo de las instituciones de intervención, tanto en el fortalecimiento de habilidades personales y relacionales, como en la conformación de un proyecto de vida prosocial y adaptativo. Los resultados demuestran la necesidad de incorporar procesos de resiliencia en el diseño de intervenciones en ámbitos de infancia vulnerada y adolescencia en situación de infracción de la ley. Estos procesos deberán formar parte de las políticas públicas en infancia y adolescencia en situación de vulnerabilidad