Artículos investigadores UV

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Search for associations containing young stars (SACY) VIII. An updated census of spectroscopic binary systems exhibiting hints of non-universal multiplicity among their associations
(European Southern Observatory (ESO), 2021) Zúñiga-Fernández, S.; Bayo, Amelia; Elliott, P.; Zamora, C.; Corvalán, G.; Haubois, X.; Corral-Santana, J. M.; Olofsson, Johan; Huélamo, N.; Sterzik, M. F.; Torres, C. A. O.; Quast, G. R.; Melo, C. H. F.
Context. Nearby young associations offer one of the best opportunities for a detailed study of the properties of young stellar and substellar objects thanks to their proximity (<200 pc) and age (∼5−150 Myr). Previous works have identified spectroscopic (<5 au) binaries, close (5−1000 au) visual binaries, and wide or extremely wide (1000−100 000 au) binaries in the young associations. In most of the previous analyses, single-lined spectroscopic binaries (SB1) were identified based on radial velocities variations. However, this apparent variation may also be caused by mechanisms unrelated to multiplicity. Aims. We seek to update the spectroscopy binary fraction of the Search for Associations Containing Young stars (SACY) sample, taking into consideration all possible biases in our identification of binary candidates, such as activity and rotation. Methods. Using high-resolution spectroscopic observations, we produced ∼1300 cross-correlation functions (CCFs) to disentangle the previously mentioned sources of contamination. The radial velocity values we obtained were cross-matched with the literature and then used to revise and update the spectroscopic binary (SB) fraction in each object of the SACY association. In order to better describe the CCF profile, we calculated a set of high-order cross-correlation features to determine the origin of the variations in radial velocities. Results. We identified 68 SB candidates from our sample of 410 objects. Our results hint that at the possibility that the youngest associations have a higher SB fraction. Specifically, we found sensitivity-corrected SB fractions of 22−11+15% for ϵ Cha, 31−14+16% for TW Hya and 32−8+9% for β Pictoris, in contrast to the five oldest associations we have sampled (∼35−125 Myr) which are ∼10% or lower. This result seems independent of the methodology used to asses membership to the associations. Conclusions. The new CCF analysis, radial velocity estimates, and SB candidates are particularly relevant for membership revision of targets in young stellar associations. These targets would be ideal candidates for follow-up campaigns using high-resolution techniques to confirm binarity, resolve orbits, and, ideally, calculate dynamical masses. Additionally, if the results on the SB fraction in the youngest associations were confirmed, it could hint at a non-universal multiplicity among SACY associations.
¿Es la teoría ideal de Rawls demasiado realista? Dibujando los límites de la igualdad
(Corporacion Filosofía Y Sociedad, 2021) Zúñiga Fajuri, Alejandra; Villavicencio Miranda, Luis
En este trabajo evaluamos si la justicia como equidad le concede demasiado a la realidad social, colapsando el ideal normativo de la teoría en la facticidad. Para lograrlo, distinguimos las teorías ideales de las no ideales en los propios términos de Rawls. Luego, analizamos críticamente el modo en que operan las desigualdades sociales en la teoría rawlsiana bajo las circunstancias de la justicia. En tercer lugar, presentamos el tránsito desde la teoría ideal al realismo político para conectarlo con la concepción de la persona de Rawls. Finalmente, el trabajo aporta construyendo una defensa del giro realista de la Teoría de la Justicia y su impacto en las discusiones actuales sobre lo que es un liberalismo igualitario posible.
Quantifying the Occurrence of Record Hot Years Through Normalized Warming Trends
(American Geophysical Union, 2021) Zeng, Xubin; Reeves Eyre, J. E. Jack; Dixon, Ross D.; Arevalo, Jorge
Surface air temperature trends and extreme events are of global concern and they are related. Here, we show that the occurrence of record hot years over different latitudes from 1960 to 2019 are more strongly correlated with the observational annual mean temperature trends normalized by internal variability. Compared with the raw trends showing Arctic amplification, the normalized trends show a tropical amplification over land. Two hot spots with more frequent occurrence of record hot years are identified: northern hemisphere ocean (vs. land) and southern hemisphere tropical land (vs. mid- and high-latitude lands). Ensemble mean results from 32 Earth system models agree with observations better than individual models, but they do not reproduce observed large differences in correlations across latitudes between normalized trends and record-breaking events over land versus ocean. Our results enable the quantification of record hot year occurrence through normalized warming trends and provide new metrics for model evaluation and improvement.
The HD 98800 quadruple pre-main sequence system Towards full orbital characterisation using long-baseline infrared interferometry
(European Southern Observatory (ESO), 2021) Zúñiga-Fernández, S.; Olofsson, Johan; Bayo, Amelia; Haubois, X.; Corral-Santana, J. M.; Lopera-Mejía, A.; Ronco, M. P.; Tokovinin, A.; Gallenne, A.; Kennedy, G. M.; Berger, J.-P.
Context. HD 98800 is a young (∼10 Myr old) and nearby (∼45 pc) quadruple system, composed of two spectroscopic binaries orbiting around each other (AaAb and BaBb), with a gas-rich disk in polar configuration around BaBb. While the orbital parameters of BaBb and AB are relatively well constrained, this is not the case for AaAb. A full characterisation of this quadruple system can provide insights on the formation of such a complex system. Aims. The goal of this work is to determine the orbit of the AaAb subsystem and refine the orbital solution of BaBb using multi-epoch interferometric observations with the Very Large Telescope Interferometer PIONIER and radial velocities. Methods. The PIONIER observations provide relative astrometric positions and flux ratios for both AaAa and BaBb subsystems. Combining the astrometric points with radial velocity measurements, we determine the orbital parameters of both subsystems. Results. We refined the orbital solution of BaBb and derived, for the first time, the full orbital solution of AaAb. We confirmed the polar configuration of the circumbinary disk around BaBb. From our solutions, we also inferred the dynamical masses of AaAb (MAa = 0.93 ± 0.09 and MAb = 0.29 ± 0.02 M⊙). We also revisited the parameters of the AB outer orbit. Conclusions. The orbital parameters are relevant to test the long-term stability of the system and to evaluate possible formation scenarios of HD 98800. Using the N-body simulation, we show that the system should be dynamically stable over thousands of orbital periods and that it made preliminary predictions for the transit of the disk in front of AaAb which is estimated to start around 2026. We discuss the lack of a disk around AaAb, which can be explained by the larger X-ray luminosity of AaAb, promoting faster photo-evaporation of the disk. High-resolution infrared spectroscopic observations would provide radial velocities of Aa and Ab (blended lines in contemporary observations), which would allow us to calculate the dynamical masses of Aa and Ab independently of the parallax of BaBb. Further monitoring of other hierarchical systems will improve our understanding of the formation and dynamical evolution of these kinds of systems.
Entre obreros y empleados. Los inicios de la lucha por el reconocimiento en la industria hotelera y gastronómica (1927-1949)
(Universidad De Chile, 2021) Yáñez, Juan Carlos
El presente artículo analiza el desarrollo del movimiento gremial hotelero y gastronómico entre 1927 y 1949. Este movimiento no ha sido estudiado por la historiografía social, abriéndose un campo de análisis provechoso para comprender las modalidades de organización, condiciones de trabajo y demandas. Para analizar la evolución del movimiento de obreros y empleados de la industria hotelera y gastronómica se hará uso, principalmente, de folletos de organizaciones y prensa del período. Se señala que las modalidades de organización evolucionaron desde el mutualismo hasta los primeros sindicatos de la década de 1920, en un contexto histórico marcado por la cooptación que llevaron a cabo las distintas autoridades de gobierno. El artículo se centra en la “lucha por el reconocimiento” de obreros y empleados, en especial, por la eliminación de la propina.
El turismo y los inicios de una industria en Chile (1910-1950)
(Instituto De Investigaciones Dr. José María Luis Mora, 2021) Yáñez, Juan Carlos
En este artículo se reconstruyen, de manera exploratoria, los antecedentes estadísticos del desarrollo del turismo en Chile entre 1910 y 1950, que permiten dimensionar sus alcances como actividad económica importante. Se parte del supuesto de que los estudios históricos sobre la materia han privilegiado enfoques socioculturales para analizar el fenómeno turístico, dando por supuesto muchas veces la existencia de una oferta y demanda turísticas, de una política sobre la materia y de un mercado laboral atractivo para desempeñarse en él. A través de la recopilación de información proveniente de guías y folletos turísticos, leyes y reglamentos, anuarios estadísticos, entre otros, se busca dimensionar los alcances reales que tuvo el turismo como actividad económica, lo que hizo posible la formulación temprana de una política de fomento turístico por parte del Estado chileno desde nes de la década de 1920.
Expression of glucose transporter-2 in murine retina: Evidence for glucose transport from horizontal cells to photoreceptor synapses
(Wiley, 2022) Yang, Ming; Chen, Yiyi; Vagionitis, Stavros; Körtvely, Elöd; Ueffing, Marius; Schmachtenberg, Oliver; Hu, Zhulin; Jiao, Kangwei; Paquet-Durand, François
The retina has the highest relative energy consumption of any tissue, depending on a steady supply of glucose from the bloodstream. Glucose uptake is mediated by specific transporters whose regulation and expression are critical for the pathogenesis of many diseases, including diabetes and diabetic retinopathy. Here, we used immunofluorescence to show that glucose transporter-2 (GLUT2) is expressed in horizontal cells of the mouse neuroretina in proximity to inner retinal capillaries. To study the function of GLUT2 in the murine retina, we used organotypic retinal explants, cultivated under entirely controlled, serum-free conditions and exposed them to streptozotocin, a cytotoxic drug transported exclusively by GLUT2. Contrary to our expectations, streptozotocin did not measurably affect horizontal cell viability, while it ablated rod and cone photoreceptors in a concentration-dependent manner. Staining for poly-ADP-ribose (PAR) indicated that the detrimental effect of streptozotocin on photoreceptors may be associated with DNA damage. The negative effect of streptozotocin on the viability of rod photoreceptors was counteracted by co-administration of either the inhibitor of connexin-formed hemi-channels meclofenamic acid or the blocker of clathrin-mediated endocytosis dynasore. Remarkably, cone photoreceptors were not protected from streptozotocin-induced degeneration by neither of the two drugs. Overall, these data suggest the existence of a GLUT2-dependent glucose transport shuttle, from horizontal cells into photoreceptor synapses. Moreover, our study points at different glucose uptake mechanisms in rod and cone photoreceptors.
Chile, tierra de encanto (1937). La propaganda turística en los inicios del turismo de masas
(Universidad De Chile, 2021) Yáñez, Juan Carlos
Este artículo analiza el documental de viaje sobre Chile del realizador norteamericano James FitzPatrick, titulado Chile, tierra de encanto (1937). A partir de él se comprenden los alcances de la imagen turística sobre Chile en la década de 1930. Las investigaciones sobre los distintos registros narrativos en torno a la experiencia del viaje y del turismo han tenido un importante desarrollo en las últimas décadas en el marco de los estudios culturales y de las representaciones. Los tradicionales diarios de viaje, pasando por las fotografías y postales como herramientas de registro y de promoción, hasta el cine como medio para acercar los destinos turísticos a públicos de distintas regiones del mundo, se han transformado en un excelente material para comprender cómo determinados destinos son presentados y el tipo de imagen que se construye sobre ellos.
Diversity of neuronal activity is provided by hybrid synapses
(Springer, 2021) Xu, Kesheng; Maidana, Jean Paul; Orio, Patricio
The coexistence of electrical and chemical synaptic communication among excitatory cells has been evidenced by neuroscientists. Nevertheless, theoretical understanding of hybrid synaptic connections in diverse dynamical states of neural networks for self-organization and robustness, still has not been fully studied. Here, we present a model of neural network that includes chemical excitatory coupling in a way of small-world topology and electrical synaptic coupling among adjacent excitatory cells for excitatory population. Firstly, we use this model to investigate the effect of electrical synaptic coupling among excitatory cells on global network behavior with the goal of theoretically understanding mechanisms of generating rich firing patterns. Secondly, we further study the emergence of various firing ripple events by considering the variation of chemical synaptic inhibition and other factors, such as network densities. We found that the excitatory population has a tendency to synchronization as the weights of electrical synaptic coupling among excitatory cells are increased. Moreover, the existence of these electrical synaptic connections can cause various firing patterns of interest by slightly changing the chemical synaptic weights. Our results pave a way in the study of the dynamical mechanisms and computational significance of the contribution of mixed synapse in the neural functions.
Plasticity in Colorectal Cancer: Why Cancer Cells Differentiate
(MDPI, 2021) Walter, Romina Judith; Sonnentag, Steffen Joachim; Orian-Rousseau, Véronique; Munoz-Sagredo, Leonel
The cancer stem cell hypothesis poses that the bulk of differentiated cells are non-tumorigenic and only a subset of cells with self-renewal capabilities drive tumor initiation and progression. This means that differentiation could have a tumor-suppressive effect. Accumulating evidence shows, however, that in some solid tumors, like colorectal cancer, such a hierarchical organization is necessary. The identification of Lgr5 as a reliable marker of normal intestinal epithelial stem cells, together with strategies to trace cell lineages within tumors and the possibility to selectively ablate these cells, have proven the relevance of Lgr5+ cells for cancer progression. On the contrary, the role of Lgr5− cells during this process remains largely unknown. In this review, we explore available evidence pointing towards possible selective advantages of cancer cells organized hierarchically and its resulting cell heterogeneity. Clear evidence of plasticity between cell states, in which loss of Lgr5+ cells can be replenished by dedifferentiation of Lgr5− cells, shows that cell hierarchies could grant adaptive traits to tumors upon changing selective pressures, including those derived from anticancer therapy, as well as during tumor progression to metastasis.
Inhibition of Caco-2 and MCF-7 cancer cells using chalcones: synthesis, biological evaluation and computational study
(Taylor & Francis, 2021) Mellado, Marco; Reyna-Jeldes, Mauricio; Weinstein-Oppenheimer, Caroline; Coddou, Claudio; Jara-Gutierrez, Carlos; Villena, Joan; Aguilar, Luis F.
Cancer is the second death cause worldwide, with breast and colon cancer among the most prevalent types. Traditional treatment strategies have several side effects that inspire the development of novel anticancer agents derived from natural sources, like chalcone derivatives. For this investigation, twenty-three chalcones (4a-w) were synthesized and evaluated as antiproliferative agents against MCF-7 and Caco-2 cells, finding three and two compounds with similar or higher antiproliferative activity than daunorubicin, while only two chalcones showed better selectivity indexes than daunorubicin on MCF-7. From these results, we developed good-performance QSAR models (r> 0.850, q2 >0.650), finding several structural features that could modify chalcone activity and selectivity. According to these models, chalcones 4w and 4t have high potency and selectivity against Caco-2 and MCF-7, respectively, which make them attractive candidates for hit-to-lead development of ROS-independent pro apoptotic agents.
Abnormal vortex formation in the right pulmonary artery after the arterial switch operation
(European Society Of Cardiology, 2021) Warmerdam, Evangeline G.; Van Assen, Hans C.; Sotelo, Julio; Grotenhuis, Heynric B.
Is Rhodamine a good tracer to predict coal transport in water?
(Universidad Católica De La Santísima Concepción, 2021) Winckler, Patricio; Molteni, Francisco; Reyes, Mauricio; Gubler, Alejandra; Sandoval, Jorge; Aleixo, Rui
A simple and low-cost experimental procedure to compare the mixing and transport of two substances in water is presented in this paper, aiming to investigate if rhodamine can predict the fate of coal transport in water. The procedure is based on acoustic Doppler techniques to characterize the flow and imaging techniques to measure the transport of substances discharged from an instantaneous point source near the free surface. To validate this procedure, several tests are carried out for rhodamine and two subsamples of coal (defined by a fine and coarse granulometry) in a flume under currents. The results show that the mixing of rhodamine resembles the finest fraction of coal that is transported as a suspended material, but fails to characterize the larger coal grains that experience sedimentation. The procedure here proposed can be expanded to characterize the mixing of substances in a body of water under other conditions, such as waves or wind driven currents.
Reduced Oligodendrocyte Precursor Cell Impairs Astrocytic Development in Early Life Stress
(Wiley, 2021) Wang, Yuxin; Su, Yixun; Yu, Guangdan; Wang, Xiaorui; Chen, Xiaoying; Yu, Bin; Cheng, Yijun; Li, Rui; Sáez, Juan C.; Yi, Chenju; Xiao, Lan; Niu, Jianqin
In animals, circadian clocks impose a daily rhythmicity to many behaviors and physiological processes. At the molecular level, circadian rhythms are driven by intracellular transcriptional/translational feedback loops (TTFL). Interestingly, emerging evidence indicates that they can also be modulated by multiple signaling pathways. Among these, Ca2+ signaling plays a key role in regulating the molecular rhythms of clock genes and of the resulting circadian behavior. In addition, the application of in vivo imaging approaches has revealed that Ca2+ is fundamental to the synchronization of the neuronal networks that make up circadian pacemakers. Conversely, the activity of circadian clocks may influence Ca2+ signaling. For instance, several genes that encode Ca2+ channels and Ca2+-binding proteins display a rhythmic expression, and a disruption of this cycling affects circadian function, underscoring their reciprocal relationship. Here, we review recent advances in our understanding of how Ca2+ signaling both modulates and is modulated by circadian clocks, focusing on the regulatory mechanisms described in Drosophila and mice. In particular, we examine findings related to the oscillations in intracellular Ca2+ levels in circadian pacemakers and how they are regulated by canonical clock genes, neuropeptides, and light stimuli. In addition, we discuss how Ca2+ rhythms and their associated signaling pathways modulate clock gene expression at the transcriptional and post-translational levels. We also review evidence based on transcriptomic analyzes that suggests that mammalian Ca2+ channels and transporters (e.g., ryanodine receptor, ip3r, serca, L- and T-type Ca2+ channels) as well as Ca2+-binding proteins (e.g., camk, cask, and calcineurin) show rhythmic expression in the central brain clock and in peripheral tissues such as the heart and skeletal muscles. Finally, we discuss how the discovery that Ca2+ signaling is regulated by the circadian clock could influence the efficacy of pharmacotherapy and the outcomes of clinical interventions.
Looking into the cradle of the grave: J22564-5910, a young post-merger hot subdwarf?
(European Southern Observatory (ESO), 2021) Vos, Joris; Pelisoli, Ingrid; Budaj, Jan; Reindl, Nicole; Schaffenroth, Veronika; Bobrick, Alexey; Geier, Stephan; Hermes, Jj; Nemeth, Peter; Østensen, Roy; Reding, Joshua S.; Uzundag, Murat; Vučković, Maja
Context. We present the discovery of J22564–5910, a new type of hot subdwarf (sdB) which shows evidence of gas present in the system and it has shallow, multi-peaked hydrogen and helium lines which vary in shape over time. All observational evidence points towards J22564–5910 being observed very shortly after the merger phase that formed it. Aims. Using high-resolution, high signal-to-noise spectroscopy, combined with multi-band photometry, Gaia astrometry, and TESS light curves, we aim to interpret these unusual spectral features. Methods. The photometry, spectra, and light curves were all analysed, and their results were combined in order to support our interpretation of the observations: the likely presence of a magnetic field combined with gas features around the sdB. Based on the triple-peaked H lines, the magnetic field strength was estimated and, by using the SHELLSPEC code, qualitative models of gas configurations were fitted to the observations. Results. All observations can either be explained by a magnetic field of ∼650 kG, which enables the formation of a centrifugal magnetosphere, or a non-magnetic hot subdwarf surrounded by a circumstellar gas disc or torus. Both scenarios are not mutually exclusive and both can be explained by a recent merger. Conclusions. J22564–5910 is the first object of its kind. It is a rapidly spinning sdB with gas still present in the system. It is the first post-merger star observed this early after the merger event, and as such it is very valuable system to test merger theories. If the magnetic field can be confirmed, it is not only the first magnetic sdB, but it hosts the strongest magnetic field ever found in a pre-white dwarf object. Thus, it could represent the long sought-after immediate ancestor of strongly magnetic white dwarfs.
GASP XXXIII. The ability of spatially resolved data to distinguish among the diferent physical mechanisms afecting galaxies in low-density environments
(American Astronomical Society (Aas), 2021) Vulcani, Benedetta; Poggianti, Bianca M.; Moretti, Alessia; Franchetto, Andrea; Bacchini, Cecilia; Mcgee, Sean; Jaffé, Yara L.; Mingozzi, Matilde; Werle, Ariel; Tomičić, Neven; Fritz, Jacopo; Bettoni, Daniela; Wolter, Anna; Gullieuszik, Marco
Galaxies inhabit a wide range of environments and therefore are affected by different physical mechanisms. Spatially resolved maps combined with the knowledge of the hosting environment are very powerful for classifying galaxies by physical process. In the context of the GAs Stripping Phenomena in galaxies (GASP), we present a study of 27 non-cluster galaxies: 24 of them were selected for showing asymmetries and disturbances in the optical morphology, suggestive of gas stripping; 3 of them are passive galaxies and were included to characterize the final stages of galaxy evolution. We therefore provide a panorama of the different processes taking place in low-density environments. The analysis of VLT/MUSE data allows us to separate galaxies into the following categories: galaxy–galaxy interactions (2 galaxies), mergers (6), ram pressure stripping (4), cosmic web stripping (2), cosmic web enhancement (5), gas accretion (3), and starvation (3). In one galaxy we identify the combination of merger and ram pressure stripping. Only 6/27 of these galaxies have just a tentative classification. We then investigate where these galaxies are located on scaling relations determined for a sample of undisturbed galaxies. Our analysis shows the successes and limitations of a visual optical selection in identifying the processes that deplete galaxies of their gas content and probes the power of IFU data in pinning down the acting mechanism.
Determination of the superoutburst cycle lengths of 206 SU UMa-type dwarf novae
(Royal Astronomical Society, 2021) Vogt, N; Puebla, E C; Contreras-Quijada, A
SU UMa stars are characterized by ‘superoutbursts’, which are brighter at maximum light and which last much longer than the more frequent ‘ordinary’ outbursts of these dwarf novae. Although there are now more than 1180 SU UMa-type dwarf novae catalogued, our knowledge on their superoutburst cycle length Cso has hitherto been limited to about 6 per cent of the entire sample of known SU UMa stars. Using public data bases we have determined new Cso values for a total of 206 additional SU UMa stars in the range 17 d < Cso < 4590 d (including some ER UMa and WZ Sge-type representants) within total time intervals between 2 and 57 yr, and with an estimated uncertainty of ±11 per cent⁠. This way, we are increasing our present knowledge of Cso values by a factor of ∼3.8. Their distribution is characterized by a broad maximum around Cso ≈ 270 d, and slowly decreasing numbers up to Cso ≈ 800 d. The domain Cso > 450 d was unexplored until now; we add here 106 cases (⁠∼51 per cent of our total sample) in this range of long cycles, implying a better statistical basis for future studies of their distribution. Our sample contains 16 known WZ Sge stars, and we propose WZ Sge membership for five others hitherto classified as ordinary SU UMa stars. Individual superoutburst timings deviate on average by about ±7 per cent of the cycle length from their overall linear ephemeris, confirming the pronounced quasi-periodic repeatability of superoutbursts. All relevant parameters are listed with their errors, and a table with individual superoutburst epochs of our targets is given, enabling future researchers to combine our results with other (past or future) observations.
Una cartografía para el principio de igualdad en Chile. análisis de la productividad dogmática entre 2000 y 2018
(Universidad De Talca, 2021) Villavicencio Miranda, Luis; Fernández Bernal, Soledad; Agüero San Juan, Claudio; Figueroa García-Huidobro, Rodolfo; Zúñiga Añazco, Yanira; Arriagada Cáceres, María Beatriz
El trabajo realiza una cartografía de la producción académica chilena relativa al principio de igualdad, enfocada en los autores y sus artículos. Respecto de los autores, ellos se ordenan en torno a ocho criterios: el número y género de autores; distribución de textos por autores; distribución de productividad en el tiempo; distribución y concentración de artículos por revistas; adscripción institucional de los autores; temáticas recurrentes; autores más citados en los artículos, y uso de la jurisprudencia en los artículos de revistas. En cuanto a los artículos elaborados por esos autores y sus temáticas, este texto esboza dos hipótesis para explicar esa producción académica.
Hacia una teoría jurídica sin género: feminismo, autonomía e igualdad relacional
(Universidade Estadual Paulista, 2021) Villavicencio Miranda, Luis; Valenzuela Oyaneder, Cecilia
En este trabajo sostenemos que la teoría jurídica ha sido servil al género masculino del derecho. Luego, esbozamos cómo esa teoría puede ser reformulada, tomando en consideración nuevas categorías conceptuales como las de sujeto incardinado y concreto. A continuación, exploramos el modo en que esa nueva forma de concebir la teoría jurídica se conecta con las ideas de autonomía relacional, igualdad y respeto. Por último, ilustramos algunos de los problemas revisados por medio de un caso ejemplar apuntando, además, las conclusiones del artículo.
Ultrasound assisted synthesis and cytotoxicity evaluation of known 2′ ,4′ -dihydroxychalcone derivatives against cancer cell lines
(Elsevier, 2021) Villena, Joan; Montenegro, Ivan; Said, Bastian; Werner, Enrique; Flores, Susana; Madrid, Alejandro
This work reports on the development of an efficient and ecofriendly ultrasound assisted method for the high yield synthesis (70.0–94.0%) of eighteen oxyalkylated derivatives of 2′ ,4′ -dihydroxychalcone. Synthesized compounds were subjected to in vitro biological assays against HT-29 (colorectal), MCF-7 (breast), and PC-3 (prostate) human tumor cell lines, these cell lines are among the ten most aggressive malignancies diagnosed in the world. Cytotoxicity evaluations showed that four of the synthesized compounds exhibited moderate to very high toxic activity against MCF-7 (IC50 = 8.4–34.3 μM) and PC-3 (IC50 = 9.3–29.4 μM) – comparable to 5-fluorouracil (IC50 16.4–22.3 μM). The same compounds only showed moderate activity against HT-29 (IC50 15.3–36.3 μM), closer to daunorubicin (IC50 15.1 μM). Next, although selectivity index (SI) of compounds was weak, compound 18 exhibited a remarkable and selective cytotoxic activity (5.8–10.57) against cancer cells. Outside of these, most compounds significantly reduced cell survival, increased reactive oxygen species (ROS) and caspase activity, and decreased mitochondrial membrane permeability. In this sense, a portion of antiproliferative activity is due to apoptosis. Notwithstanding, due to its remarkable response, chalcone 18 may be a potential alternative as a chemotherapeutic anti-carcinogen.

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