Growth and Branching of Gold nanoparticles Through MesoporousSilica Thin Films

Composite materials made of mesoporous oxide thin films containing metallic nanoparticles are of high interest in various fields, including catalysis, biosensing and non-linear optics. We demonstrate in this work the fabrication of such composite materials containing a sub-monolayer of gold nanoparticles (GNPs) of various shapes covered with mesoporous silica thin films. Additionally, the shape of the GNPs (and thus their optical properties) can be modified in situ through seeded growth and branching. Such growth proceeds upon wetting with HAuCl 4 solution, a surfactant (cetyltrimethylammonium bromide, CTAB) and a mild reducing agent (ascorbic acid, AA). The effect of varying several reaction parameters (time and CTAB and AA concentrations) was evaluated, showing that more anisotropic particles are obtained at longer reaction times, lower CTAB concentration and higher AA concentration. The final shape of the GNPs was also found to depend on their initial shape and size, as well as the pore size of the mesoporous film covering them. Because the growth proceeds through the pores of the film, it may lead to shapes that are not easily obtained in solution, such as particles with branches on one side only. Finally, we have confirmed that no damage was induced to the mesoporous silica structure during the growth process and thus the final particles remain well covered by the thin film, which can eventually be used as a filter between the GNPs and the outer medium.Fil: Angelomé, Paula C.. Universidad de Vigo; EspañaFil: Pastoriza Santos, Isabel. Universidad de Vigo; EspañaFil: Pérez Juste, Jorge. Universidad de Vigo; EspañaFil: Rodríguez-González, Benito. Universidad de Vigo; EspañaFil: Zelcer, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Soler Illia, Galo Juan de Avila Arturo. Universidad de Buenos Aires; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Liz Marzán, Luis M.. Universidad de Vigo; Españ

Evaluación del crecimiento in vitro de explantes de piña perolera (Ananas comosus) usando la técnica de organogénesis

From an economic standpoint, pineapple (Ananas comosus) is one of the most important fruits in Colombia. A decade ago, the Perolera variety was the most cropped cultivar of the Santander department, however, the variety has been displaced considerably due to the lack of technical extension services and theintroduction of new varieties. This research project was carried out with the intention to conserve the speciesthrough the development of in vitro pineapple explants using the organogenesis technique. Meristemsthat have been extracted from the crown of the Perolera pineapple variety were used for this purpose. Four disinfectant treatments were evaluated by looking at the different kinds of disinfectant exposure times.The treatment that gave the best results in terms of contaminant-free explants was the T2: Commercialdetergent + Tween 80 for 8 minutes, ethyl alcohol at 70% for 1 minute and sodium hypochlorite at 1,5% over10 minutes, with a contamination rate of 7% and 93% of the explants thriving. For the establishment phase,it was found that the medium MS MEP1 with 100% solid salts supplemented with 2000 μl/L BAP - 1000 μl/L ANA - 1000 μl/L AIA and 500 μl/L thiamine enabled 90 % of the pineapple explants to continue developing four weeks after planting. Similarly, the medium containing 3000 μl/L of BAP for the multiplication phase permitted an average proliferation of 4.62 shoots with 9.12 leaves per shoot and a length of 2.25 mm.Desde el punto de vista económico, la piña (Ananas comosus) es una de las frutas más importantes de Colombia. Hace una década, la variedad Perolera era la variedad más cultivada del departamento de Santander, sin embargo, la variedad se ha desplazado considerablemente debido a la falta de servicios de extensión técnica y la introducción de nuevas variedades. Este proyecto de investigación se llevó a cabo con la intención de conservar la especie mediante el desarrollo de explantes de piña in vitro mediante la técnicade organogénesis. Para ello se utilizaron meristemas extraídos de la corona de la variedad de piña Perolera. Se evaluaron cuatro tratamientos desinfectantes observando los diferentes tipos de tiempos de exposición a los desinfectantes. El tratamiento que mejores resultados dio en cuanto a explantes libres de contaminantes fue el T2: Detergente comercial + Tween 80 durante 8 minutos, alcohol etílico al 70% durante 1 minuto ehipoclorito de sodio al 1,5% durante 10 minutos, con una contaminación tasa de crecimiento del 7% y 93% delos explantes. Para la fase de establecimiento, se encontró que el medio MS MEP1 con 100% de sales sólidas suplementado con 2000 ul / L BAP - 1000 ul / L ANA - 1000 ul / L AIA y 500 ul / L tiamina permitió que el90% de los explantes de piña se desarrollaran cuatro semanas después de la siembra. Asimismo, el medio que contenía 3000 ul / L de BAP para la fase de multiplicación permitió una proliferación promedio de 4.62 brotes con 9.12 hojas por brote y una longitud de 2.25 mm.

Synthesis and in vitro evaluation of an antiangiogenic cancerspecific dual-targeting 177Lu-Au-nanoradiopharmaceutical

The aim of this research was to synthesize and chemically characterize a cancer-specific 177Lu-Aunanoradiopharmaceutical based on gold nanoparticles (NPs), the nuclear localization sequence (NLS)-Arg-Gly- Asp peptide and an aptamer (HS-pentyl-pegaptanib) to target both the a(v)b(3) integrin and the vascular endothelial growth factor (VEGF) overexpressed in the tumor neovasculature, as well as to evaluate by the tube formation assay, the nanosystem capability to inhibit angiogenesis. 177Lu-NP-RGD-NLS-Aptamer was obtained with a radiochemical purity of 99 ± 1%. Complete inhibition of tube formation (angiogenesis) was demonstrated when endothelial cells (EA.hy926), cultured in a 3D-extracellular matrix support, were treated with the developed nanosystem.Mexican National Council of Science and Technology (CONACYT-SEP-CB-2014-01-242443)

High-dose intravenous immunoglobulins might modulate inflammation in COVID-19 patients

High-dose of IVIG show immunomodulatory properties that may be useful for controlling the hyperinflammatory status observed in COVID-19 patients. The use of high-dose of intravenous immunoglobulins (IVIGs) as immunomodulators for the treatment of COVID-19-affected individuals has shown promising results. IVIG reduced inflammation in these patients, who progressively restored respiratory function. However, little is known about how they may modulate immune responses in COVID-19 individuals. Here, we have analyzed the levels of 41 inflammatory biomarkers in plasma samples obtained at day 0 (pretreatment initiation), 3, 7, and 14 from five hospitalized COVID-19 patients treated with a 5-d course of 400 mg/kg/d of IVIG. The plasmatic levels of several cytokines (Tumor Necrosis Factor, IL-10, IL-5, and IL-7), chemokines (macrophage inflammatory protein-1α), growth/tissue repairing factors (hepatic growth factor), complement activation (C5a), and intestinal damage such as Fatty acid-binding protein 2 and LPS-binding protein showed a progressive decreasing trend during the next 2 wk after treatment initiation. This trend was not observed in IVIG-untreated COVID-19 patients. Thus, the administration of high-dose IVIG to hospitalized COVID-19 patients may improve their clinical evolution by modulating their hyperinflammatory and immunosuppressive status

Patrimonio cultural inmaterial y memoria del pueblo ngäbe-buglé de Coto Brus

Este proyecto es continuidad de otro inscrito con un el título “Patrimonio e interculturalidad: la herencia de los pueblos indígenas en zonas fronterizas”, que se ejecutó en los territorios indígenas Curré y Térraba, ubicados en la fronterade pueblos bruncas y broran-terbi con otros pueblos indígenas de la Región Brunca. Esta zona se reconoce por la biodiversidad y variedad étnica-cultural, pues en ella habitan cinco pueblos indígenas, que desde el siglo XVI iniciaron contacto con la otredad occidental, con la consecuente desestructuración de sus sociedades.Este texto es una producción de la Universidad de Costa Rica con apoyo de la Comisión Costarricense de Cooperación con la UNESCO Coordinadora del Proyecto VAS-EC-437: Giselle Chang Vargas. Centro de Investigaciones Antropológicas (CIAN). Compilación y edición de textos escritos Giselle Chang Vargas.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Centro de Investigaciones Antropológicas (CIAN)UCR::Vicerrectoría de Acción Socia

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger Observatory

The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, $(\sec \theta)_\mathrm{max}$, sensitive to the mass composition of cosmic rays above $3 \times 10^{18}$ eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modelling that must be resolved before the mass composition can be inferred from $(\sec \theta)_\mathrm{max}$.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

The exposure of the hybrid detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The "hybrid" detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic