(FBIOyF) Departamento de Química Física - Artículo de Revista

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  • ÍtemAcceso Abierto
    Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory
    (Institute of Physics, 2024-01-01) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
    The combined fit of the measured energy spectrum and shower maximum depth distributions of ultra-high-energy cosmic rays is known to constrain the parameters of astrophysical models with homogeneous source distributions. Studies of the distribution of the cosmic-ray arrival directions show a better agreement with models in which a fraction of the flux is non-isotropic and associated with the nearby radio galaxy Centaurus A or with catalogs such as that of starburst galaxies. Here, we present a novel combination of both analyses by a simultaneous fit of arrival directions, energy spectrum, and composition data measured at the Pierre Auger Observatory. The model takes into account a rigidity-dependent magnetic field blurring and an energy-dependent evolution of the catalog contribution shaped by interactions during propagation. We find that a model containing a flux contribution from the starburst galaxy catalog of around 20% at 40 EeV with a magnetic field blurring of around 20◦ for a rigidity of 10 EV provides a fair simultaneous description of all three observables. The starburst galaxy model is favored with a significance of 4.5σ (considering experimental systematic effects) compared to a reference model with only homogeneously distributed background sources. By investigating a scenario with Centaurus A as a single source in combination with the homogeneous background, we confirm that this region of the sky provides the dominant contribution to the observed anisotropy signal. Models containing a catalog of jetted active galactic nuclei whose flux scales with the γ-ray emission are, however, disfavored as they cannot adequately describe the measured arrival directions.
  • ÍtemAcceso Abierto
    Radio measurements of the depth of air-shower maximum at the Pierre Auger Observatory
    (American Physical Society, 2023-01-08) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
    The Auger Engineering Radio Array (AERA), part of the Pierre Auger Observatory, is currently the largest array of radio antenna stations deployed for the detection of cosmic rays, spanning an area of 17 km2 with 153 radio stations. It detects the radio emission of extensive air showers produced by cosmic rays in the 30-80 MHz band. Here, we report the AERA measurements of the depth of the shower maximum (Xmax), a probe for mass composition, at cosmic-ray energies between 1017.5 and 1018.8 eV, which show agreement with earlier measurements with the fluorescence technique at the Pierre Auger Observatory. We show advancements in the method for radio Xmax reconstruction by comparison to dedicated sets of corsika/coreas air-shower simulations, including steps of reconstruction-bias identification and correction, which is of particular importance for irregular or sparse radio arrays. Using the largest set of radio air-shower measurements to date, we show the radio Xmax resolution as a function of energy, reaching a resolution better than 15 g cm-2 at the highest energies, demonstrating that radio Xmax measurements are competitive with the established high-precision fluorescence technique. In addition, we developed a procedure for performing an extensive data-driven study of systematic uncertainties, including the effects of acceptance bias, reconstruction bias, and the investigation of possible residual biases. These results have been cross-checked with air showers measured independently with both the radio and fluorescence techniques, a setup unique to the Pierre Auger Observatory.
  • ÍtemAcceso Abierto
    Elimination of Arsenic using sorbents derived from Chitosan and Iron Oxides, applying factorial designs
    (Multidisciplinary Digital Publishing Institute (MDPI), 2023-11-01) Batistelli, Marianela; Bultri, Julián; Hernandez Trespalacios, Mayra; Mangiameli, María Florencia; Gribaudo, Lina; Bellú, Sebastián; Frascaroli, María Inés; González, Juan Carlos; https://orcid.org/0000-0002-6338-676X; https://orcid.org/0000-0003-2314-7980
    Arsenic is highly toxic, affecting millions of people in many regions of the world. That is why developing economic and efficient technologies is imperative to eliminate it. Sorption techniques are attractive as efficient and inexpensive sorbents can be used. Chitosan is an abundant, naturally occurring, biodegradable, low-cost biopolymer that can be combined with metal oxide to enhance its removability. This work aimed to synthesize a new chitosan–magnetite-based sorbent for arsenic removal. The synthesized sorbent does not present pores, and when using FT-IR, functional groups of the chitosan and the presence of As(V) in the sorbent treated with arsenic were identified. The synthesized magnetite was characterized using XRD spectroscopy. Application of the central composite design model showed that 0.22 g of the sorbent at pH 6.0 could remove 27.6% of As(V). Kinetic data, fitted with the pseudo-first and -second order models, indicated an ion exchange sorption and activation energy of 28.1–31.4 kJ mol−1 . The isotherms were fitted with the Langmuir model, indicating favorable monolayer adsorption with high affinity. The sorption energy calculated using Dubinin Radushkevich, 9.60–8.80 kJ mol−1 , confirms a sorption mechanism mediated by ion exchange. The thermodynamic parameters of the process were ∆G◦ (−21.7/−19.7 kJ mol−1 ), ∆H◦ (16.7 kJ mol−1 ) and ∆S ◦ (123.3 J mol−1 K−1 ).
  • ÍtemAcceso Abierto
    Factors associated with mortality among hospitalized patients with COVID-19 disease treated with convalescent plasma
    (American Society for Microbiology, 2023-11-08) Perichon, Armando M.; Acosta, Andrea; Di Tulio, Liliana; Munuce, María José; Pezzotto, Stella; Bottasso, Oscar; http://orcid.org/0000-0002-8472-7965
    The use of convalescent plasma (CP) for hospitalized patients with SARSCoV-2 infection might be a useful option in certain settings. Soon after the outbreak of COVID-19, the National Ministry of Health of Argentina recommended the use of CP transfusion for hospitalized patients with COVID-19 disease. Between 1 June and 3 October 2020, 480 patients, excluding those on invasive mechanical ventilation (IMV), received at least one CP infusion in the province of Santa Fe. We aimed to find factors associated with mortality among this cohort of patients. The median age was 60 years (interquartile range: 49–69 years) and 320 (66.7%) were males. Most of these patients (93.75%) received a single CP infusion, 82.1% and 95.6% before day 4 and day 7 of hospitalization, respectively. Anti-SARS-CoV-2 titers were determined in the CP units administered using Elecsys Anti-SARS-CoV-2 S assay. At 28 days of follow-up, 250 patients were discharged (52.1%), 131 (27.3%) remained hospitalized without and 16 (3.3%) with oxygen requirement, 27 (5.6%) were on IMV, and 56 (11.7%) had died. In the multivariate logistic regression analysis, the factors significantly associated with 28-day mortality were (i) requirement of IMV, (ii) the administration of CP after the third day of hospitalization, (iii) age, and (iv) number of comorbidities. The qualitative and quantitative analyses of antibodies against SARS-CoV-2 in the infused CP were not associated with mortality. Our findings may imply a seemingly favorable effect of CP administration among patients with severe COVID-19 disease when infused sooner after hospitalization.
  • ÍtemAcceso Abierto
    Effect of Metal Environment and Immobilization on the Catalytic Activity of a Cu Superoxide Dismutase Mimic
    (MDPI, 2023-10-27) Richezzi, Micaela; Ferreyra, Joaquín; Signorella, Sharon; Palopoli, Claudia; Terrestre, Gustavo; Pellegri, Nora; Hureau, Christelle; Signorella, Sandra R.; https://orcid.org/0009-0001-5428-1130; https://orcid.org/0000-0003-3339-0239; https://orcid.org/0000-0002-1547-6891
    The Cu(II)/Cu(I) conversion involves variation in the coordination number and geometry around the metal center. Therefore, the flexibility/rigidity of the ligand plays a critical role in the design of copper superoxide dismutase (SOD) mimics. A 1,3-Bis[(pyridin-2-ylmethyl)(propargyl)amino]propane (pypapn), a flexible ligand with an N4-donor set, was used to prepare [Cu(pypapn)(ClO4)2], a trans-Cu(II) complex whose structure was determined by the X-ray diffraction. In DMF or water, perchlorate anions are exchanged with solvent molecules, affording [Cu(pypan)(solv)2]2+ that catalyzes O2•− dismutation with a second-order rate constant kMcF = 1.26 × 107 M−1 s−1, at pH 7.8. This high activity results from a combination of ligand flexibility, total charge, and labile binding sites, which places [Cu(pypapn)(solv)2]2+ above other mononuclear Cu(II) complexes with more favorable redox potentials. The covalent anchoring of the alkyne group of the complex to azide functionalized mesoporous silica through “click” chemistry resulted in the retention of the SOD activity and improved stability. A dicationic Cu(II)-N4-Schiff base complex encapsulated in mesoporous silica was also tested as an SOD mimic, displaying higher activity than the free complex, although lower than [Cu(pypapn)(solv)2]2+. The robustness of covalently attached or encapsulated doubly charged Cu(II) complexes in a mesoporous matrix appears as a suitable approach for the design of copper-based hybrid catalysts for O2•− dismutation under physiological conditions.
  • ÍtemAcceso Abierto
    A catalog of the highest-energy cosmic rays recorded during phase I of operation of the Pierre Auger Observatory
    (American Astronomical Society, 2023-02-01) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
  • ÍtemAcceso Abierto
    Search for spatial correlations of Neutrinos with Ultra-high-energy Cosmic Rays
    (Institute of Physics, 2022-08-03) The ANTARES collaboration; The IceCube collaboration; The Pierre Auger collaboration; The Telescope Array collaboration; Binet, V.; Micheletti, M. I.
  • ÍtemAcceso Abierto
    Arrival directions of vosmic rays above 32 EeV from phase one of the Pierre Auger Observatory
    (Institute of Physics, 2022-08-20) Micheletti, M. I.; Binet, V.; The Pierre Auger collaboration
  • ÍtemAcceso Abierto
    A search for photons with energies above 2×1017 eV using hybrid data from the low energy extensions of the Pierre Auger Observatory
    (Institute of Physics, 2022-07-08) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
  • ÍtemEmbargo
    Biospeckle laser as a tool to analyze erythrocyte aggregation
    (Society of Photo-optical Instrumentation Engineers, 2022-12-02) Toderi, Martín A.; Riquelme, Bibiana Doris; Galizzi, Gustavo E.
  • ÍtemAcceso Abierto
    Physical-mathematical model to predict the kinetic coagulation process by clotting activity of bacterial endopeptidases
    (MedCrave, 2022-08) Mancilla Canales, Manuel Arturo; Folmer Côrrea, Ana Paula; Riquelme, Bibiana Doris; Brandelli, Adriano; Risso, Patricia Hilda
  • ÍtemAcceso Abierto
    Tara gum–bovine sodium caseinate acid gels: Stabilisation of W/W emulsions
    (Wiley, 2020-02-13) Hidalgo, María Eugenia; Ingrassia, Romina; Nielsen, Nadia Sol; Porfiri, María Cecilia; Tapia-Maruri, Daniel; Risso, Patricia Hilda
  • ÍtemAcceso Abierto
    Effects of cholesterol extraction process and fat and whey protein additions on ice cream mixes
    (2019-04-23) Hidalgo, María Eugenia; Bordino, Juliana; Acciarri, Giuliana; Fernández, Juan Manuel; Rozycki, Sergio; Risso, Patricia Hilda
    The aim of this work was to evaluate the cholesterol extraction process in ice cream mixes (ICMs) by using β-cyclodextrin (βCD) and to analyze the effect of this extraction on the ICM rheological, stability, and sensory characteristics. The effects of fat and whey protein (WP) additions on ICM stability were also evaluated. The maximum percentage obtained for cholesterol extraction was 93.6%. The flow curves indicated that ICM showed a thixotropic behavior before and after cholesterol extraction, which was enhanced when the fat content and/or percentage of βCD increased. The stability of ICM with cholesterol-reduced content (RCho-ICM) was influenced by the fat content and/or the presence of WP. The RCho-ICM with the highest fat and/or WP addition showed less tendency to melt and had the smallest amount of accumulated molten liquid. These latter ICMs presented the slowest melting rates. Also, RCho-ICMs proved to be more stable than ICMs. RCho-ICM samples obtained with a ratio of βCD/fat content of 1% w/w were evaluated by a trained sensory panel. In addition, an acceptability test of the sample with better sensory attributes was conducted. Practical Application: The effects of a cholesterol extraction process and fat and whey protein additions on the rheological and stability characteristics of ice cream mixes were evaluated. The extraction of cholesterol from an ice cream mix is interesting from a nutritional point of view and the extraction process of cholesterol itself may also help to improve the mix stability by controlling the fat and/or whey protein contents. These findings may prove useful as a starting point for the rational design of new functional ice cream mixes.
  • ÍtemAcceso Abierto
    The energy spectrum of cosmic rays beyond the turn-down around 1017 eV as measured with the surface detector of the Pierre Auger Observatory
    (Springer Science and Business, 2021-11-02) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
  • ÍtemEmbargo
    New insights into the mechanics of erythrocytes: effects of radiation and several drugs of biomedical interest
    (Bulgarian Academy of Sciences, 2022) Riquelme, Bibiana Doris; Toderi, Martín A.; Batista, M.; Galassi, Mariel Elisa; Castellini, Horacio V.; Estrada, Ezequiel; Alet, Analía I.
  • ÍtemAcceso Abierto
  • ÍtemAcceso Abierto
    Measurement of the fluctuations in the number of muons in extensive Air showers with the Pierre Auger Observatory
    (American Physical Society, 2021-04-16) Freire, M. M.; The Pierre Auger collaboration
  • ÍtemAcceso Abierto
    Calibration of the underground muon detector of the Pierre Auger Observatory
    (IOP Publishing, 2021-04-06) The Pierre Auger collaboration; Freire, M. M.; Micheletti, M. I.
  • ÍtemAcceso Abierto
    Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger Observatory
    (IOP Publishing, 2022-01-17) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
  • ÍtemAcceso Abierto
    Physicochemical and mechanical properties of a new cold-set emulsion gel system and the effect of quinoa protein fortification
    (Elsevier, 2022-01-06) Ingrassia, Romina; Busti, Pablo Andrés; Boeris, Valeria