Publications by authors named "Ignacio Castro"

. New applications of 3D printing have recently appeared in the fields of radiotherapy and radiology, but the knowledge of many radiological characteristics of the compounds involved is still limited. Therefore, studies are needed to improve our understanding about the transport and interaction of ionizing radiation in these materials.

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  • A study was conducted on pediatric patients with sellar-suprasellar tumors to create a deep learning algorithm for better classification using MRI images.
  • 226 Chilean patients were analyzed, categorized into three groups: healthy controls, craniopharyngioma, and other sellar/suprasellar tumors.
  • The findings showed a high predictive positive value (PPV) and negative predictive value (NPV) for the algorithm, highlighting the potential of explainable AI in assisting radiological diagnoses.
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Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in drylands, remain virtually unknown.

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Organizational responsibilities can give people power but also expose them to scrutiny. This tension leads to divergent predictions about the use of potentially sensitive language: power might license it, while exposure might inhibit it. Analysis of peoples' language use in a large corpus of organizational emails using standardized Linguistic Inquiry and Word Count (LIWC) measures shows a systematic difference in the use of words with potentially sensitive (ethnic, religious, or political) connotations.

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Mitochondrial aconitase (ACO2) has been postulated as a redox sensor in the tricarboxylic acid cycle. Its high sensitivity towards reactive oxygen and nitrogen species is due to its particularly labile [4Fe-4S] prosthetic group which yields an inactive [3Fe-4S] cluster upon oxidation. Moreover, ACO2 was found as a main oxidant target during aging and in pathologies where mitochondrial dysfunction is implied.

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Background: Granulosa cell ovarian tumor (GCT) is characterized by a pathognomonic mutation in the FOXL2 gene (402 C > G) that leads to an overactivation of steroidogenesis. CYP17 is a key enzyme in such process and can be inhibited by ketoconazole.

Methods: We designed a phase II clinical trial to assess the efficacy of ketoconazole in advanced GCT and conducted several in vitro studies to support the clinical findings.

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  • This paper investigates how the density of 3D printed plesiotherapy applicators impacts dosimetry in brachytherapy treatments, focusing on varying densities from air to water using common FDM materials.
  • The study involved creating applicators using 3D printing, with specific designs for measuring dose and gamma index at critical points using EBT films during clinical conditions.
  • Results indicate that while the applicators' density does not affect dose at prescription depth, it significantly influences surface dose measurements near the applicator, highlighting the importance of considering material density to minimize skin toxicity in treatments.
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Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide.

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The spread of COVID-19 and the lockdowns that followed led to an increase in activity on online social networks. This has resulted in users sharing unfiltered and unreliable information on social networks like WhatsApp, Twitter, Facebook, etc. In this work, we give an extended overview of how Pakistan's population used public WhatsApp groups for sharing information related to the pandemic.

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In humans, the loss of frataxin results in Friedreich's Ataxia, a neurodegenerative disease, in which a deficit in the iron-sulfur cluster assembly is observed. In this work, we analyzed three frataxin variants in which one tryptophan was replaced by a glycine: W155G, W168G and W173G. As expected, given its localization in the assembly site, W155G was not able to activate the desulfurase activity of the supercomplex for iron-sulfur cluster assembly.

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COVID-19, an infectious disease caused by the SARS-CoV-2 virus, was declared a pandemic by the World Health Organisation (WHO) in March 2020. By mid-August 2020, more than 21 million people have tested positive worldwide. Infections have been growing rapidly and tremendous efforts are being made to fight the disease.

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The relationships between conformational dynamics, stability and protein function are not obvious. Frataxin (FXN) is an essential protein that forms part of a supercomplex dedicated to the iron-sulfur (Fe-S) cluster assembly within the mitochondrial matrix. In humans, the loss of FXN expression or a decrease in its functionality results in Friedreich's Ataxia, a cardio-neurodegenerative disease.

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Mammalian frataxin is a small mitochondrial protein involved in iron sulfur cluster assembly. Frataxin deficiency causes the neurodegenerative disease Friedreich's Ataxia. Valuable knowledge has been gained on the structural dynamics of frataxin, metal-ion-protein interactions, as well as on the effect of mutations on protein conformation, stability and internal motions.

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Background: With the aim to inform end of life public policies, the place of death in Chile, its trends and associated factors were analysed.

Materials And Methods: A cross sectional using publically available death database from 1990 to 2014 was conducted. The proportion of hospital deaths was selected as the main outcome.

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Friedreich's ataxia is a disease caused by a decrease in the levels of expression or loss of functionality of the mitochondrial protein frataxin (FXN). The development of an active and stable recombinant variant of FXN is important for protein replacement therapy. Although valuable data about the mature form FXN81-210 has been collected, not enough information is available about the conformation of the frataxin precursor (FXN1-210).

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NANOG is a pluripotency transcription factor in embryonic stem cells; however, its role in adult tissues remains largely unexplored. Here we show that mouse NANOG is selectively expressed in stratified epithelia, most notably in the oesophagus where the Nanog promoter is hypomethylated. Interestingly, inducible ubiquitous overexpression of NANOG in mice causes hyperplasia selectively in the oesophagus, in association with increased cell proliferation.

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To investigate if the cooperation between the Rgr oncogene and the inactivation of INK4b (a CDK inhibitor), as described previously in a sarcoma model, would be operational in a lymphoid system in vivo, we generated a transgenic/knockout murine model. Transgenic mice expressing the Rgr oncogene under a CD4 promoter were crossed into a p15(INK4b)-deficient background. Unexpectedly, mice with a complete ablation of both p15(INK4b) alleles had a lower tumor incidence and higher survival rate when compared with CD4-Rgr progeny with homozygous or heterozygous expression of p15(INK4b).

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Ischemia-reperfusion (IR) lung injury is a significant cause of morbidity and mortality in certain clinical scenarios that include transplantation, thromboendarterectomy and reexpansion injury of the lung. Edema of the contralateral lung after IR injury of one lung has been reported and this study was aimed to clarify the pathophysiology of this phenomenon. One-lung ischemia/hypoxia followed by reperfusion with either blood or an acellular plasma substitute was achieved in an isolated rabbit lung model by hilum clamping.

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Hypocapnia/alkalosis is a consequence of several lung and metabolic pathologies. The aim of this study was to determine whether the increase of fluid filtration rate (FFR) that occurs during Hypocapnia/alkalosis circumstances is determined by hypocapnia, alkalosis or both. 7 groups were formed (N=36) using isolated rabbit lungs.

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Background And Objective: Mechanical obstruction has been considered the prime determinant of haemodynamic changes after pulmonary embolism (PE); however, the function of vasoconstrictive and inflammatory mediators in the physiopathology of this disease is unclear. The aim of this investigation was to study the effect of an anti-inflammatory and a vasodilator in a setting of induced PE.

Methods: A prospective, laboratory study was undertaken using 30 New Zealand white rabbits.

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An instrumental method based on a chemometric model of the medium region of the infrared (MIR) was developed to analyse total sugar content and the proportions of glucose, fructose and sucrose. In order to construct the model, a set of 127 standard aqueous solutions of different sugars in the concentration range 0-20% (w/v) were prepared and analysed in the interval 4900-700 cm(-1). The MIR was transformed by normalisation, correction of baseline using the second derivative, and suppression of the signals of water and carbon dioxide.

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