RESUMEN
Models of terrestrial planet formation predict that the final stages of planetary assembly-lasting tens of millions of years beyond the dispersal of young protoplanetary disks-are dominated by planetary collisions. It is through these giant impacts that planets like the young Earth grow to their final mass and achieve long-term stable orbital configurations1. A key prediction is that these impacts produce debris. So far, the most compelling observational evidence for post-impact debris comes from the planetary system around the nearby 23-million-year-old A-type star HD 172555. This system shows large amounts of fine dust with an unusually steep size distribution and atypical dust composition, previously attributed to either a hypervelocity impact2,3 or a massive asteroid belt4. Here we report the spectrally resolved detection of a carbon monoxide gas ring co-orbiting with dusty debris around HD 172555 between about six and nine astronomical units-a region analogous to the outer terrestrial planet region of our Solar System. Taken together, the dust and carbon monoxide detections favour a giant impact between large, volatile-rich bodies. This suggests that planetary-scale collisions, analogous to the Moon-forming impact, can release large amounts of gas as well as debris, and that this gas is observable, providing a window into the composition of young planets.
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One of the most crucial biological indicators in tracking long-term variations in the reproductive cycle is sexual development. Scorpaena porcus (Linnaeus, 1758), commonly known as the black scorpionfish, is a small teleost from the family Scorpaenidae. Much is known about its ecology, but data on its reproductive and defense systems are still lacking. Antimicrobial peptides (AMPs), such as piscidins, are integral components of the innate immune system in fish. These peptides exhibit a wide range of activity against bacteria, fungi, viruses, and protozoa and act as the first line of host defense. This study aims to investigate the primary sexual development stages in male and female gonads of black scorpionfish, providing additional knowledge on the reproductive biology of this teleost while evaluating concomitant changes in the expression of a Piscidin-1 antimicrobial peptide. The results show a histological, morpho-structural change from the immature stage to the developing virgin stage. Immunohistochemical analyses show that germinal and somatic cells are strongly reactive to Piscidin-1 in both gonads at an early ontogeny stage. These data suggest that Piscidin-1 may play a key role in the local defense system of scorpionfish gonads at this delicate stage, which is critical for the continuation and maintenance of the species. The present findings are potentially useful for a better understanding of the reproductive cycle of this fish, improving our knowledge of the interaction between the immune system and reproduction.
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The striped dolphin (Stenella coeruleoalba) is a medium-sized pelagic dolphin with a single external nasal opening (blowhole) located in the rostral and dorsal regions of the skull. The nasal cavity is divided into three sections: the olfactory, respiratory, and vestibular areas. The surface epithelium lining the regio vestibularis is the first tissue in the nose to be directly affected by environmental antigens. Cetaceans have a significant amount of mucosa-associated lymphoid tissue (MALT) located throughout their bodies. The lymphoid tissue found in the nasal mucosa is known as nose- or nasopharynx-associated lymphoid tissue (NALT). NALT has not yet been studied in dolphins, but it has been identified and documented in humans and laboratory rodents. This study utilized toll-like receptor 2 (TLR2), CD4, Langerin/CD207, and inducible nitric oxide synthase to characterize, for the first time, immune cells in the mucosal regio vestibularis of the S. coeruleoalba nasal cavity using confocal microscopy immunofluorescence techniques. The findings revealed scattered immune cells immunoreactive to the tested antibodies, present in both the epithelial tissue lining the nasal cavity vestibulum and the underlying connective tissue. This study enhances our comprehension of the immune system of cetaceans. RESEARCH HIGHLIGHTS: This study provides new insights into NALT in S. coeruleoalba. This research deepens the knowledge of the skin of cetaceans.
Asunto(s)
Inmunohistoquímica , Tejido Linfoide , Cavidad Nasal , Stenella , Animales , Cavidad Nasal/anatomía & histología , Tejido Linfoide/anatomía & histología , Stenella/anatomía & histología , Mucosa Nasal , Microscopía Confocal , Óxido Nítrico Sintasa de Tipo II/metabolismo , Antígenos CD4/metabolismo , Antígenos CD4/análisis , Delfines/anatomía & histologíaRESUMEN
As we learn more about the multi-scale interstellar medium (ISM) of our Galaxy, we develop a greater understanding for the complex relationships between the large-scale diffuse gas and dust in Giant Molecular Clouds (GMCs), how it moves, how it is affected by the nearby massive stars, and which portions of those GMCs eventually collapse into star forming regions. The complex interactions of those gas, dust and stellar populations form what has come to be known as the ecology of our Galaxy. Because we are deeply embedded in the plane of our Galaxy, it takes up a significant fraction of the sky, with complex dust lanes scattered throughout the optically recognizable bands of the Milky Way. These bands become bright at (sub-)millimetre wavelengths, where we can study dust thermal emission and the chemical and kinematic signatures of the gas. To properly study such large-scale environments, requires deep, large area surveys that are not possible with current facilities. Moreover, where stars form, so too do planetary systems, growing from the dust and gas in circumstellar discs, to planets and planetesimal belts. Understanding the evolution of these belts requires deep imaging capable of studying belts around young stellar objects to Kuiper belt analogues around the nearest stars. Here we present a plan for observing the Galactic Plane and circumstellar environments to quantify the physical structure, the magnetic fields, the dynamics, chemistry, star formation, and planetary system evolution of the galaxy in which we live with AtLAST; a concept for a new, 50m single-dish sub-mm telescope with a large field of view which is the only type of facility that will allow us to observe our Galaxy deeply and widely enough to make a leap forward in our understanding of our local ecology.
There are many individual components contributing to the overall evolution of our Galaxy, the Milky Way. Through understanding the physics and chemistry of the Galaxy around us, we better understand our origins, our environment, and where we're going. Here we outline a number of observational surveys of our Galaxy that would produce a step change in our understanding of the evolution of the Galaxy around us, both as a template for others, and as the only way of understanding our place in the larger Universe. We present surveys of the Galactic Plane focusing on the dust and magnetic fields, chemistry, and dynamics of the gas. We then suggest surveys of local stars and star forming regions to uncover the origins of stars, planets and how those planetary systems evolve over the course of their lives, helping to put our Sun and Solar System in context. These types of observations require simultaneously sensitive, long wavelength (between 0.3 and 3 millimetre) observations as well as a large coverage of the sky, and cannot be done with current observatories operating at these wavelengths. Future leaps in understanding these systems will require a new telescope; a large telescope at a good observing location with a large field of view. This telescope, the Atacama Large Sub-mm Telescope (AtLAST; http://atlast-telescope.org/) is being developed, and here we are presenting the science cases for this new telescope from the point of view of our Galaxy. Together, these studies will revolutionise our understanding of the history and evolution of our Galaxy and bring us yet another step closer to understanding our place in, and the evolution of, our Universe.
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The introduction of pollutants, such as thiacloprid and benzo[a]pyrene (B[a]P), into the waters of urbanized coastal and estuarine areas through fossil fuel spills, domestic and industrial waste discharges, atmospheric inputs, and continental runoff poses a major threat to the fauna and flora of the aquatic environment and can have a significant impact on the internal defense system of invertebrates such as mussels. Using monoclonal and polyclonal anti-Toll-like receptor 2 (TLR2) and anti-inducible nitric oxide synthetase (iNOS) antibodies for the first time, this work aims to examine hemocytes in the mantle and gills of M. galloprovincialis as biomarkers of thiacloprid and B[a]P pollution and analyze their potential synergistic effect. To pursue this objective, samples were exposed to the pollutants, both individually and simultaneously. Subsequently, oxidative stress biomarkers were evaluated by enzymatic analysis, while tissue changes and the number of hemocytes in the different contaminated groups were assessed via histomorphological and immunohistochemical analyses. Our findings revealed that in comparison to a single exposure, the two pollutants together significantly elevated oxidative stress. Moreover, our data may potentially enhance knowledge on how TLR2 and iNOS work as part of the internal defense system of bivalves. This would help in creating new technologies and strategies, such as biosensors, that are more suitable for managing water pollution, and garnering new details on the condition of the marine ecosystem.
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Radial velocity surveys suggest that the Solar System may be unusual and that Jupiter-like planets have a frequency < 20% around solar-type stars. However, they may be much more common in one of the closest associations in the solar neighbourhood. Young moving stellar groups are the best targets for direct imaging of exoplanets and four massive Jupiter-like planets have been already discovered in the nearby young ß Pic Moving Group (BPMG) via high-contrast imaging, and four others were suggested via high precision astrometry by the European Space Agency's Gaia satellite. Here we analyze 30 stars in BPMG and show that 20 of them might potentially host a Jupiter-like planet as their orbits would be stable. Considering incompleteness in observations, our results suggest that Jupiter-like planets may be more common than previously found. The next Gaia data release will likely confirm our prediction.
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Ionic liquid crystals (ILCs), that is, ionic liquids exhibiting mesomorphism, liquid crystalline phases, and anisotropic properties, have received intense attention in the past years. Among others, this is due to their special properties arising from the combination of properties stemming from ionic liquids and from liquid crystalline arrangements. Besides interesting fundamental aspects, ILCs have been claimed to have tremendous application potential that again arises from the combination of properties and architectures that are not accessible otherwise, or at least not accessible easily by other strategies. The current review highlights recent developments in ILC research, starting with some key fundamental aspects. Further subjects covered include the synthesis and variations of modern ILCs, including the specific tuning of their mesomorphic behavior. The review concludes with reflections on some applications that may be within reach for ILCs and finally highlights a few key challenges that must be overcome prior and during true commercialization of ILCs.
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Despite the extensive literature available on laser at the present, there are few articles about the temperature of laser radiation and its propagation on dental hard tissues. The present study general objective is to evaluate in vitro the effect of temperature increase produced by the laser radiation of 940 nm on the dental hard tissues and, as specific objectives a) analyze current parameters using 940 nm laser on dental hard tissues b) assess the most appropriate criteria for this wavelengthon dental hard tissues. 4 groups of 5 teeth each(lower incisors, upper incisors, canines and molars) were irradiated with 6 powers and frequencies (0.1 to 0.4 W, in continuous or pulsed mode). The results of this study allow us to ensure that, in the chosen parameters, major powers, but deliveredin pulsed manner, generate less temperature rise. Extremely significant differences were found between groups of lower incisors and molars. 0.1 W power, pulsed mode for 20 ms, with 20 millisecondintervals, generated less than 4 Celsius degrees of temperature increase in all the cases studied. Inconclusion, the use of powers of up to 0.4W, inpulsed mode, generated thermal effects of less than4 Celsius degrees...
Apesar da extensa literatura disponível sobre o laser na atualidade, há poucos artigos sobre a temperatura da radiação laser e sua propagação nos tecidos duros dentais. O presente estudo teve por objetivo geral avaliar in vitro o efeito do aumento da temperatura produzida pela radiação laser de 940 nm sobre os tecidos duros dentais e, como objetivos específicos a) analisar os parâmetros atuais utilizados para o laser de 940 nmn os tecidos dentais duros b) avaliar o parâmetro mais adequado para esse comprimento de onda sobre os tecidos dentais duros. Quatro grupos de 5 dentes cada (incisivos inferiores, incisivos superiores, caninos e molares) foram irradiados com 6 potências e frequências (0,1 a 0,4 W, em modo contínuo ou pulsado). Os resultados deste estudo permitem afirmar que, nos parâmetros escolhidos, as potências mais altas, mas entregues em forma pulsada, geram menos aumento de temperatura. Diferenças significativas foram encontradas entre os grupos de incisivos e molares inferiores. A potência de 0,1 W,modo pulsado para 20 ms, com 20 milissegundos de intervalo, gerou menos de 4 graus Celsius de aumento da temperatura em todos os casos estudados. Em conclusão, o uso de potências de até 0,4W, no modo pulsado, gerou efeitos térmicos de menos de 4 graus Celsius...