Strategies to tailor the architecture of dual Ag/Fe-oxide nano-heterocrystals—interfacial and morphology effects on the magnetic behavior

Bifunctional nanostructured architectures have shown appealing properties, since a single entity can combine the diverse properties of its individual constituents. Particularly, by growing Fe-oxide domains over Ag nanoparticles, the plasmonic and superparamagnetic properties can be combined in a single particle. Beyond the multifunctionality of this system, there are several properties that emerge from intrinsic factors, such as: interface and/or morphology. In this study, we present the synthesis protocols to obtain two sets of heterocrystals, each one with different morphology: dimer and flower-like. In addition, the magnetization behavior of these hybrid nano-heterocrystals is investigated and discussed. These nanomaterials were built by a seed assisted heterogeneous nucleation process, carried out in organic solvents of high boiling point, using the same batch of silver nanoparticles with a mean size of 6 nm as seeds, and tuning the electron-donor capacity of the reaction environment at the thermal decomposition of the iron precursor. Ag/Fe3O4 heterocrystals with dimer and flower-like morphologies were obtained. The synthesis protocols for generating these types of nanomaterials are discussed step-by-step. Structural and morphological properties were determined by transmission electron microscopy, x-ray diffraction and x-ray absorption fine structure. DC magnetization results suggest that the silver/magnetite coupling generates an increase of the blocking temperature in comparison to those obtained from pure magnetite. This behavior could be linked to a possible increase in the magnetic anisotropy produced by an additional disorder at the Ag–Fe3O4 interface. The higher interface area of the Ag/Fe3O4 heterocrystals with flower-like architecture leads to a higher blocking temperature and a stronger magnetic anisotropy. These results are supported by AC susceptibility data.Fil: Tancredi Gentili, Pablo. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Laboratorio de Sólidos Amorfos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Moscoso Londoño, Oscar. Universidad Autónoma de Manizales; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidade Estadual de Campinas; BrasilFil: Rivas Rojas, Patricia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Laboratorio de Sólidos Amorfos; ArgentinaFil: Wolff, U.. Leibniz Institute for Solid State and Materials Research; AlemaniaFil: Socolovsky, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Knobel, M.. Universidade Estadual de Campinas; BrasilFil: Muraca, D.. Universidade Estadual de Campinas; Brasi

Investigating the Paracrine Role of Perinatal Derivatives: Human Amniotic Fluid Stem Cell-Extracellular Vesicles Show Promising Transient Potential for Cardiomyocyte Renewal

Cardiomyocyte renewal represents an unmet clinical need for cardiac regeneration. Stem cell paracrine therapy has attracted increasing attention to resurge rescue mechanisms within the heart. We previously characterized the paracrine effects that human amniotic fluid-derived stem cells (hAFSC) can exert to provide cardioprotection and enhance cardiac repair in preclinical models of myocardial ischemia and cardiotoxicity. Here, we analyze whether hAFSC secretome formulations, namely, hAFSC conditioned medium (hAFSC-CM) over extracellular vesicles (hAFSC-EVs) separated from it, can induce cardiomyocyte renewal. c-KIT+ hAFSC were obtained by leftover samples of II trimester prenatal amniocentesis (fetal hAFSC) and from clinical waste III trimester amniotic fluid during scheduled C-section procedures (perinatal hAFSC). hAFSC were primed under 1% O2 to enrich hAFSC-CM and EVs with cardioactive factors. Neonatal mouse ventricular cardiomyocytes (mNVCM) were isolated from cardiac tissue of R26pFUCCI2 mice with cell cycle fluorescent tagging by mutually exclusive nuclear signal. mNVCM were stimulated by fetal versus perinatal hAFSC-CM and hAFSC-EVs to identify the most promising formulation for in vivo assessment in a R26pFUCCI2 neonatal mouse model of myocardial infarction (MI) via intraperitoneal delivery. While the perinatal hAFSC secretome did not provide any significant cardiogenic effect, fetal hAFSC-EVs significantly sustained mNVCM transition from S to M phase by 2-fold, while triggering cytokinesis by 4.5-fold over vehicle-treated cells. Treated mNVCM showed disorganized expression of cardiac alpha-actinin, suggesting cytoskeletal re-arrangements prior to cell renewal, with a 40% significant downregulation of Cofilin-2 and a positive trend of polymerized F-Actin. Fetal hAFSC-EVs increased cardiomyocyte cell cycle progression by 1.8-fold in the 4-day-old neonatal left ventricle myocardium short term after MI; however, such effect was lost at the later stage. Fetal hAFSC-EVs were enriched with a short isoform of Agrin, a mediator of neonatal heart regeneration acting by YAP-related signaling; yet in vitro application of YAP inhibitor verteporfin partially affected EV paracrine stimulation on mNVCM. EVs secreted by developmentally juvenile fetal hAFSC can support cardiomyocyte renewal to some extension, via intercellular conveyance of candidates possibly involving Agrin in combination with other factors. These perinatal derivative promising cardiogenic effects need further investigation to define their specific mechanism of action and enhance their potential translation into therapeutic opportunity

Cell cycle block by p53 activation reduces SARS-CoV-2 release in infected alveolar basal epithelial A549-hACE2 cells

SARS-CoV viruses have been shown to downregulate cellular events that control antiviral defenses. They adopt several strategies to silence p53, key molecule for cell homeostasis and immune control, indicating that p53 has a central role in controlling their proliferation in the host. Specific actions are the stabilization of its inhibitor, MDM2, and the interference with its transcriptional activity. The aim of our work was to evaluate a new approach against SARS-CoV-2 by using MDM2 inhibitors to raise p53 levels and activate p53-dependent pathways, therefore leading to cell cycle inhibition. Experimental setting was performed in the alveolar basal epithelial cell line A549-hACE2, expressing high level of ACE2 receptor, to allow virus entry, as well as p53 wild-type. Cells were treated with several concentrations of Nutlin-3 or RG-7112, two known MDM2 inhibitors, for the instauration of a cell cycle block steady-state condition before and during SARS-CoV-2 infection, and for the evaluation of p53 activation and impact on virus release and related innate immune events. The results indicated an efficient cell cycle block with inhibition of the virion release and a significant inhibition of IL-6, NF-kB and IFN-λ expression. These data suggest that p53 is an efficient target for new therapies against the virus and that MDM2 inhibitors deserve to be further investigated in this field

La búsqueda de la identidad en el período 1975-1983

A partir del análisis de resoluciones y expedientes judiciales conservados en el Archivo General de los Tribunales de Córdoba, mediante el relevamiento y sistematización de los procesos de guardas y adopciones tramitados entre 1975 y 1983 en los Juzgados de Menores y Juzgados Civiles, el proyecto se propone: identificar casos potenciales de apropiación de hijos de personas víctimas del Terrorismo de Estado, y elaborar una base de datos que contribuya a dar respuesta a las consultas sobre identidad presentadas ante el Poder Judicial de Córdoba. Es un trabajo cuya mirada se centra en la escena judicial de la época del “Proceso de Reorganización Nacional” con el propósito de colaborar en la promoción de los derechos humanos y la restitución de derechos vulnerados.Fil: Bonzano, María de los Ángeles. Universidad Católica de Córdoba. Facultad de Derecho y Ciencias Sociales; Argentin

La búsqueda de la identidad en el período 1975-1983

A partir del análisis de resoluciones y expedientes judiciales conservados en el Archivo General de los Tribunales de Córdoba, mediante el relevamiento y sistematización de los procesos de guardas y adopciones tramitados entre 1975 y 1983 en los Juzgados de Menores y Juzgados Civiles, el proyecto se propone: identificar casos potenciales de apropiación de hijos de personas víctimas del Terrorismo de Estado, y elaborar una base de datos que contribuya a dar respuesta a las consultas sobre identidad presentadas ante el Poder Judicial de Córdoba. Es un trabajo cuya mirada se centra en la escena judicial de la época del “Proceso de Reorganización Nacional” con el propósito de colaborar en la promoción de los derechos humanos y la restitución de derechos vulnerados.Fil: Bonzano, María de los Ángeles. Universidad Católica de Córdoba. Facultad de Derecho y Ciencias Sociales; Argentin

State of the Art of Invasive Group A Streptococcus Infection in Children: A Scoping Review of the Literature with a Focus on Predictors of Invasive Infection

Currently, it remains unclear why some children develop invasive group A Streptococcus (iGAS) and how to manage this condition. Therefore, to explore available works in the literature, we performed a scoping review aiming to analyze the current literature on clinical presentation of different illnesses outcomes of iGAS, with a specific focus on predictors of invasive infection, including an assessment of the prodromal stages of the disease and the possible presence of previous non-invasive GAS infections in children that later developed iGAS. Methods: We conducted a systematic search on PubMed and SCOPUS of all pediatric studies reporting iGAS cases, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. For those studies in which multivariable analysis investigating iGAS risk factors was performed, a second review was performed and reported in detail. Results: A total of 209 studies were included. Five studies investigated risk factors for iGAS, the most relevant being varicella infection, chronic underlying illness, presence of the speC gene in GAS strains, acetaminophen and ibuprofen use, children nonwhite, living in low-income households, exposure to varicella at home, persistent high fever, having more than one other child in the home, and new use of NSAIDs. Although we observed a progressive increase in the number of papers published on this topic, no trials investigating the benefits of clindamycin or intravenous immunoglobulins were found and low-to-middle-income countries were found to be poorly represented in the current literature. Conclusions: Our scoping review highlights important gaps regarding several aspects of iGAS in children, including prodromic presentation and optimal treatment strategies. There is also little representation of low–middle-income countries. The current literature does not allow the performance of systematic reviews or meta-analyses, but this work should inform healthcare professionals, policy makers, and funding agencies on which studies to prioritize on this topic

Step-by-step synthesis of iron-oxide nanoparticles attached to graphene oxide: A study on the composite properties and architecture

A set of nanocomposites made of iron oxide nanoparticles covalently bonded to graphene oxide and reduced graphene oxide was successfully prepared. The synthesis was carried out in a precise step-by-step process in order to carefully control the nanocomposite formation. The nanocomposites were characterized by a range of techniques to verify the components arrangement according to the proposed strategy. Over the different samples, an in-depth study by Small Angle X-Ray Scattering (SAXS) and DC-Magnetometry was accomplished to analyze in detail the structure and properties of the systems. The results from this work indicate that the increase of the nanoparticle to graphene oxide ratio and the chemical reduction from graphene oxide to reduced graphene oxide modify the spatial distribution and the architecture of the nanoparticles over the sheets, leading to the formation of localized assemblies and bundle-like structures that have a significant impact on the macroscopicmagnetic behavior.Fil: Tancredi Gentili, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Moscoso Londoño, Oscar. Universidad Autónoma de Manizales; Colombia. Universidade Estadual de Campinas; BrasilFil: Rivas Rojas, Patricia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Knobel, Marcelo. Universidade Estadual de Campinas; BrasilFil: Socolovsky, Leandro Martín. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Tuning dipolar magnetic interactions by controlling individual silica coating of iron oxide nanoparticles

Single and fixed size core, core–shell nanoparticles of iron oxides coated with a silica layer of tunable thickness were prepared by chemical routes, aiming to generate a frame of study of magnetic nanoparticles with controlled dipolar interactions. The batch of iron oxides nanoparticles of 4.5 nm radii, were employed as cores for all the coated samples. The latter was obtained via thermal decomposition of organic precursors, resulting on nanoparticles covered with an organic layer that was subsequently used to promote the ligand exchange in the inverse microemulsion process, employed to coat each nanoparticle with silica. The amount of precursor and times of reaction was varied to obtain different silica shell thicknesses, ranging from 0.5 nm to 19 nm. The formation of the desired structures was corroborated by TEM and SAXS measurements, the core single-phase spinel structure was confirmed by XRD, and superparamagnetic features with gradual change related to dipolar interaction effects were obtained by the study of the applied field and temperature dependence of the magnetization. To illustrate that dipolar interactions are consistently controlled, the main magnetic properties are presented and analyzed as a function of center to center minimum distance between the magnetic cores.Fil: Rivas Rojas, Patricia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Tancredi Gentili, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Moscoso Londoño, Oscar. Universidade Estadual de Campinas; Brasil. Universidad Autónoma de Manizales; ColombiaFil: Knobel, M.. Universidade Estadual de Campinas; BrasilFil: Socolovsky, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentin

Te seguimos buscando… Derecho a la identidad y prácticas judiciales durante el Terrorismo de Estado en Argentina

These pages are dedicated to the socialization of a research experience in the Cordoba´s Court General File (Argentina). The research was oriented to the survey, systematization and analysis of the custodies and adoptions which were made in the civil and children courts of Cordoba´s city between 1975 and 1983. This project followed two main objectives: to establish the relationship of the biological and adoptive identity of the adopted children in those years, and the identification of possible unlawful appropriations related to the State of Terrorism. In this framework, this article aims to account for the hypotheses that were reached -after working with a complete documental batch- in respect with some judicial practices of that period related to identity right. Particularly, and as regards the approach of those practices at the moment of inquiring about the systematic plan of unlawful child appropriation developed during the last dictatorship in Argentina, we will attempt to show: first, that it was not necessary to forge the procedure of judicial management of children to obtain the substitution or suppression of their biological identity and, second, that the mechanisms that facilitated the inscription of children as own, worked inside judicial processes as well.Socializaremos aquí los resultados de una investigación desarrollada en el Archivo General de los Tribunales de Córdoba (Argentina), orientada al relevamiento, la sistematización y el análisis de las guardas y adopciones tramitadas en los juzgados civiles y de menores de la ciudad de Córdoba entre 1975 y 1983. Sus objetivos fueron: establecer la vinculación de la identidad biológica y adoptiva de los niños adoptados en esos años, e identificar posibles apropiaciones ilegales vinculadas al Terrorismo de Estado. En ese marco, presentaremos aquí las hipótesis a las que se arribó en el primer trabajo realizado en nuestro país con un fondo documental completo de estas características, respecto de algunas prácticas judiciales de aquel período en relación al derecho a la identidad. En particular, y en cuanto al abordaje de éstas al momento de indagar en torno al plan sistemático de apropiación ilegal de niños desarrollado durante la última dictadura en Argentina, intentaremos mostrar: por una parte, que no era necesario fraguar el procedimiento en relación a la gestión judicial de menores para lograr la sustitución o supresión de su identidad biológica y, por la otra, que el conjunto de mecanismos y dispositivos que facilitaban la inscripción de los niños como hijos propios, funcionaban también al interior de los procesos judiciales