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Borospherene in the Nanohoop : Complexation and Aromaticity of Neutral and Dioxidized Cycloparaphenylene Supramolecules with B40 and C60 Fullerenes
No full textPublisher Copyright: © 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.Supramolecular complexes of carbon nanohoops with fullerenes play a key role for the design of novel nanomaterials with technological applications. Herein we investigate with density functional theory (DFT) methods the capability of neutral and dioxidized cycloparaphenylenes (CPPs) to encapsulate all-boron fullerene B40. Our results show that [9]CPP and [10]CPP are feasible host candidates to encapsulate B40 displaying comparable complexation energies with the all-carbon analog [10]CPP⊃C60. Upon dioxidation the host-guest interactions are not affected, whereas the positive charge is delocalized on the CPPs leading to global aromatic character of the hosts. Consequently, the dicationic complexes [n]CPP2+⊃B40 and [10]CPP2+⊃C60 display augmented global shielding cones that strongly shield the guests, as manifested by large upfield shifts in 11B-NMR and 13C-NMR signals. Hence, CPP complexes with carbon fullerenes can be extended borospherene B40 host-guest complexes, as well as to doubly oxidized species stabilized by global host aromaticity, expanding our understanding of carbon nanohoop complexes to boron-based fullerenes
Viscous dynamics associated with hypoexcitation and structural disintegration in neurodegeneration via generative whole-brain modeling
No full textPublisher Copyright: © 2024 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.INTRODUCTION: Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) lack mechanistic biophysical modeling in diverse, underrepresented populations. Electroencephalography (EEG) is a high temporal resolution, cost-effective technique for studying dementia globally, but lacks mechanistic models and produces non-replicable results. METHODS: We developed a generative whole-brain model that combines EEG source-level metaconnectivity, anatomical priors, and a perturbational approach. This model was applied to Global South participants (AD, bvFTD, and healthy controls). RESULTS: Metaconnectivity outperformed pairwise connectivity and revealed more viscous dynamics in patients, with altered metaconnectivity patterns associated with multimodal disease presentation. The biophysical model showed that connectome disintegration and hypoexcitability triggered altered metaconnectivity dynamics and identified critical regions for brain stimulation. We replicated the main results in a second subset of participants for validation with unharmonized, heterogeneous recording settings. DISCUSSION: The results provide a novel agenda for developing mechanistic model-inspired characterization and therapies in clinical, translational, and computational neuroscience settings
Infrared spectroscopy reveals metal-independent carbonic anhydrase activity in crotonyl-CoA carboxylase/reductase
No full textPublisher Copyright: © 2024 The Royal Society of Chemistry.The conversion of CO2 by enzymes such as carbonic anhydrase or carboxylases plays a crucial role in many biological processes. However, in situ methods following the microscopic details of CO2 conversion at the active site are limited. Here, we used infrared spectroscopy to study the interaction of CO2, water, bicarbonate, and other reactants with β-carbonic anhydrase from Escherichia coli (EcCA) and crotonyl-CoA carboxylase/reductase from Kitasatospora setae (KsCcr), two of the fastest CO2-converting enzymes in nature. Our data reveal that KsCcr possesses a so far unknown metal-independent CA-like activity. Site-directed mutagenesis of conserved active site residues combined with molecular dynamics simulations tracing CO2 distributions in the active site of KsCCr identify an ‘activated’ water molecule forming the hydroxyl anion that attacks CO2 and yields bicarbonate (HCO3−). Computer simulations also explain why substrate binding inhibits the anhydrase activity.The conversion of CO2 by enzymes such as carbonic anhydrase or carboxylases plays a crucial role in many biological processes. However, in situ methods following the microscopic details of CO2 conversion at the active site are limited. Here, we used infrared spectroscopy to study the interaction of CO2, water, bicarbonate, and other reactants with β-carbonic anhydrase from Escherichia coli (EcCA) and crotonyl-CoA carboxylase/reductase from Kitasatospora setae (KsCcr), two of the fastest CO2-converting enzymes in nature. Our data reveal that KsCcr possesses a so far unknown metal-independent CA-like activity. Site-directed mutagenesis of conserved active site residues combined with molecular dynamics simulations tracing CO2 distributions in the active site of KsCCr identify an ‘activated’ water molecule forming the hydroxyl anion that attacks CO2 and yields bicarbonate (HCO3−). Computer simulations also explain why substrate binding inhibits the anhydrase activity. Altogether, we demonstrate how in situ infrared spectroscopy combined with molecular dynamics simulations provides a simple yet powerful new approach to investigate the atomistic reaction mechanisms of different enzymes with CO
Diseño de un sistema de economía en proveedores de nube orientado a tecnologías amazon web services para la empresa Ecommerce-cl
No full textEl objetivo de este proyecto es desarrollar un sistema de optimización de costos
para los servicios de cloud computing utilizados por la empresa, con el fin de
maximizar la eficiencia tanto en el uso de dichos servicios como en la gestión de
los costos asociados.
Para alcanzar este objetivo, se realizará un análisis en profundidad del uso actual
de los recursos en los proveedores de cloud computing, identificando
oportunidades donde puedan aplicarse técnicas de "cloud economics" para la
reducción de costes.
A partir de este análisis, se diseñará un sistema dinámico que identifique
oportunidades de ahorro en los servicios de nube utilizados por la organización.
Finalmente, se presentará un análisis comparativo que evaluará el impacto de la
implementación del sistema diseñado en contraste con la utilización de un
modelo de costes por demanda, con el fin de justificar la adopción e
implementación de dicho sistema.The objective of this project is to develop a cost optimization system for the cloud
computing services used by the company, aiming to maximize efficiency both in
the utilization of these services and in the management of associated costs.
To achieve this objective, an in-depth analysis of the current usage of resources
from cloud service providers will be conducted, identifying opportunities to apply
"cloud economics" techniques for cost reduction.
Based on this analysis, a dynamic system will be designed to identify savings
opportunities in the cloud services utilized by the organization.
Finally, a comparative analysis will be presented to evaluate the impact of
implementing the designed system in contrast to a pay-as-you-go cost model,
with the purpose of justifying the adoption and implementation of the proposed
system
"Our duty in the current times": Boundaries and Nationalism between Chile and Argentina (1892-1899)
Get PDFPublisher Copyright: © 2024 Universidad Nacional de Colombia. All rights reserved.During the nineteenth century, Chile and Argentina had several border disputes, both over the Strait of Magellan and Patagonia, which concluded with the Boundary Treaty of 1881. However, these problems emerged again in the austral zone and increased tension in the 1890s, when nationalism and the arms race were mixed up with the boundary issue. Therefore, our research question is: ¿Why did the Chilean- Argentinian dispute increase if there were a treaty and a protocol in force during that decade? For this, the objectives are to: 1) evaluate unresolved limit points between both states; and 2) comprehend the nationalism and arms race atmosphere of that period. A methodology of document source analysis using archives, books, period press, and a historical-geopolitical approach within a defined time frame (1892-1999) will be utilized in this study. The results aim to demonstrate that both states, despite their agreements, sought to hasten the resolution of controversies by engaging not only state institutions but also society as a whole
Elites políticas, discrecionalidad de agencias y gobernanza anticorrupción en Chile
No full textPublisher Copyright: © 2024 Centre for Latin American Research and Documentation/Centro de Estudios y Documentación Latinoamericanos (CEDLA). All rights reserved.Between 2015 and 2018, Chile experienced several political corruption scandals that implicated the country's political elite across the party spectrum. However, the outcomes of the ensuing judicial investigations have faced wide-spread criticism for being unsatisfactory, failing to set legal precedence, and weakening Chile's anti-corruption governance. This article addresses the gap between Chile's strong structural and formal conditions and the limited legal consequences faced by politicians involved in corruption. It examines the factors that allowed most politicians and their allies to avoid significant legal penalties. Drawing on different literatures related to professional politicians and political elites, institutional weakness, and agency discretion, the article analyses four prominent political corruption cases. We argue that favourable appointments of sympathetic executives allowed the Chilean political elite to exert control over the discretionary powers of state agencies involved in the legal processes. The article relies on a press review, secondary literature, and expert interviews
Lo culto y lo oculto. El rol de lo vernáculo en la historia de la arquitectura chilena
No full textl siguiente artículo analiza –desde un punto de vista teórico a través de un trabajo de revisión y análisis de fuentes impresas– el discurso oficial de la historia de la arquitectura en Chile1. Se confrontan los referentes construidos aceptados formalmente por la disciplina con aquellos otros ejemplos que suelen ser ignorados u ocultados y que forman parte del patrimonio vernáculo nacional construido, particularmente aquel de los pueblos originarios. Se argumentará por qué dicho patrimonio debiese ser considerado dentro de lo que se denomina la historia de la arquitectura oficial o culta, relevando y visibilizando estas evidencias construidas vernáculas, al mismo tiempo de contribuir con el enriquecimiento e inclusión de la pertinencia cultural en los referentes arquitectónicos utilizados en la discusión disciplinar
School principals as translators of inclusion policiesConditioned commitment, rewarding inclusion, and privatizing translation
No full textPublisher Copyright: © 2024, Arizona State University. All rights reserved.The objective of this research was to explore the translations produced by school principals regarding school inclusion policies in the Chilean educational system. In theoretical terms, the notion of translation from the policy enactment approach or the implementation of policies was used to understand the translations produced by the participants regarding these policies. Methodologically, a qualitative study was carried out consisting of the application of semi-structured interviews to 40 directors and directors of public and subsidized schools from different regions of Chile. Among the main findings, first, a conditioned commitment of the participants toward compliance with the policies, expressing adherence and resistance, stands out. Secondly, it was evidenced that the principals maintained that inclusion would be a priority in schools if it were rewarded for its compliance. Lastly, it was identified that some of the participants transfer the responsibility for the translation of the policies to actors external to the educational institution, such as the Educational Technical Consultancies, which privatizes the task of interpreting and generating meanings and practices around these policies
Preparación y caracterización de nanopartículas de lignina desde plantas de diferente origen
No full textPublisher Copyright: © 2024 by the authors.This article presents new research on producing lignin nanoparticles (LNPs) using the antisolvent nanoprecipitation method. Acetone (90%) served as the lignin solvent and water (100%) as the antisolvent, using five types of lignins from various sources. Comprehensive characterization techniques, including NMR, GPC, FTIR, TEM, and DLS, were employed to assess both lignin and LNP properties. The antioxidant activity of the LNPs was evaluated as well. The results demonstrated the successful formation of spherical nanoparticles below 100 nm with initial lignin concentrations of 1 and 2%w/v. The study highlighted the crucial role of lignin purity in LNP formation and colloidal stability, noting that residual carbohydrates adversely affect efficiency. This method offers a straightforward, environmentally friendly approach using cost-effective solvents, applicable to diverse lignin sources. The innovation of this study lies in its demonstration of a cost-effective and eco-friendly method to produce stable, nanometric-sized spherical LNPs. These LNPs have significant potential as reinforcement materials due to their reinforcing capability, hydrophilicity, and UV absorption. This work underscores the importance of starting material purity for optimizing the process and achieving the desired nanometric dimensions, marking a pioneering advancement in lignin-based nanomaterials