(FBIOyF) Departamento de Química Física - Artículo de Revista

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https://rephip.unr.edu.ar/handle/2133/8620

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Search for photons above 1018 eV by simultaneously measuring the atmospheric depth and the muon content of air showers at the Pierre Auger Observatory
(American Physical Society, 2024-09-25) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
The Pierre Auger Observatory is the most sensitive instrument to detect photons with energies above 1⁢017 eV. It measures extensive air showers generated by ultrahigh energy cosmic rays using a hybrid technique that exploits the combination of a fluorescence detector with a ground array of particle detectors. The signatures of a photon-induced air shower are a larger atmospheric depth of the shower maximum (𝑋max) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced cascades. In this work, a new analysis technique in the energy interval between 1 and 30 EeV (1 EeV=1⁢018 eV) has been developed by combining the fluorescence detector-based measurement of 𝑋max with the specific features of the surface detector signal through a parameter related to the air shower muon content, derived from the universality of the air shower development. No evidence of a statistically significant signal due to photon primaries was found using data collected in about 12 years of operation. Thus, upper bounds to the integral photon flux have been set using a detailed calculation of the detector exposure, in combination with a data-driven background estimation. The derived 95% confidence level upper limits are 0.0403, 0.01113, 0.0035, 0.0023, and 0.0021 km−2 sr−1 yr−1 above 1, 2, 3, 5, and 10 EeV, respectively, leading to the most stringent upper limits on the photon flux in the EeV range. Compared with past results, the upper limits were improved by about 40% for the lowest energy threshold and by a factor 3 above 3 EeV, where no candidates were found and the expected background is negligible. The presented limits can be used to probe the assumptions on chemical composition of ultrahigh energy cosmic rays and allow for the constraint of the mass and lifetime phase space of super-heavy dark matter particles.
Acceso Abierto
Impact of the magnetic horizon on the interpretation of the Pierre Auger Observatory spectrum and composition data
(IOP Publishing, 2024-07-30) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
The flux of ultra-high energy cosmic rays reaching Earth above the ankle energy (5 EeV) can be described as a mixture of nuclei injected by extragalactic sources with very hard spectra and a low rigidity cutoff. Extragalactic magnetic fields existing between the Earth and the closest sources can affect the observed CR spectrum by reducing the flux of low-rigidity particles reaching Earth. We perform a combined fit of the spectrum and distributions of depth of shower maximum measured with the Pierre Auger Observatory including the effect of this magnetic horizon in the propagation of UHECRs in the intergalactic space. We find that, within a specific range of the various experimental and phenomenological systematics, the magnetic horizon effect can be relevant for turbulent magnetic field strengths in the local neighbourhood in which the closest sources lie of order Brms ≃ (50–100) nG (20 Mpc/ds)(100 kpc/Lcoh) 1/2, with ds the typical intersource separation and Lcoh the magnetic field coherence length. When this is the case, the inferred slope of the source spectrum becomes softer and can be closer to the expectations of diffusive shock acceleration, i.e., ∝ E−2. An additional cosmic-ray population with higher source density and softer spectra, presumably also extragalactic and dominating the cosmic-ray flux at EeV energies, is also required to reproduce the overall spectrum and composition results for all energies down to 0.6 EeV.
Acceso Abierto
Effect of quinoa protein concentration and oil volume fraction on the physicochemical and mechanical properties of alginatebased emulsion gels
(Wiley, 2024-04-04) Lingiardi , Nadia; Galante, Micaela; Spelzini, Darío; https://orcid.org/0000-0003-1968-8637; https://orcid.org/0000-0001-7958-6056; https://orcid.org/0000-0002-5023-9330
Background: This work studies emulsion gel (EG) formulation with quinoa proteins (QP), high-oleic sunflower oil and alginate, and the effect of QP concentration (0.5–1–2%) and the oil volume fraction (10–30–50%) on the physicochemical and mechanical properties of EG systems. EGs were tested for their microstructural and textural attributes, color, and water holding capacity as well as for their thermal, physical, and oxidative stability. Results: The microstructure of EG showed that with increasing QP concentrations, the gel structure tended to be much denser, with oil droplets entrapped within the network. A significant decrease in droplet diameter with increasing QP concentration (p = 0.015) and oil volume fraction (p < 0.000) was observed. Hardness mean value was 2.8 N ± 0.5, reaching the highest value with 1 and 2% QP and 30% oil (p < 0.000). Cohesiveness shows a similar trend to that observed for hardness, while springiness showed the opposite behavior. As for adhesiveness, there were no significant differences between samples. EG have high lightness with slight yellow and green contributions. The mean water holding capacity was 88 ± 4%, and after heat treatment all samples exhibited a good fluid retention, significantly lower for the lower oil volume fraction (p = 0.001). EG, also proved to be highly stable against creaming and oxidative damage. Conclusion: Results suggest that EG could be useful to create a new generation of healthier and innovative products that could substitute animal fat and deliver nutrients and biological compounds, thus improving food quality.
Acceso Abierto
Constraints on metastable superheavy dark matter coupled to sterile neutrinos with the Pierre Auger Observatory
(American Physical Society, 2024-04-08) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration
Dark matter particles could be superheavy, provided their lifetime is much longer than the age of the Universe. Using the sensitivity of the Pierre Auger Observatory to ultrahigh energy neutrinos and photons, we constrain a specific extension of the Standard Model of particle physics that meets the lifetime requirement for a superheavy particle by coupling it to a sector of ultralight sterile neutrinos. Our results show that, for a typical dark coupling constant of 0.1, the mixing angle θm between active and sterile neutrinos must satisfy, roughly, θm ≲ 1.5 × 10−6ðMX=109 GeVÞ−2 for a mass MX of the dark-matter particle between 108 GeV and 1011 GeV.
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Hemocompatibility and hemorheological activity of aqueous extracts from Phyllanthus sellowianus: effects on in vitro glycated erythrocytes
(Elsevier, 2024-12) Mascaro Grosso, Hermano; Buszniez , Patricia; Riquelme, Bibiana Doris
Introduction: Phyllanthus sellowianus (Klotzsch) Müll Arg. is an Argentinian and Brazilian native plant used to treat diabetes. In vascular diseases like diabetes, erythrocytes form anomalous aggregates resistant to dissociation, associated with high glucose levels. This work aims to evaluate the hemocompatibility and hemorheological activity of aqueous extracts from P. sellowianus and its anti-diabetic activity using in vitro glycated erythrocytes as occur by hyperglycemia. Methods: For this work, P. sellowianus specimens were collected on the Nogoyá River coast, Argentina, and morphoanatomical identified. Infusion, maceration, digestion, and cooking extracts were prepared with collected leaves and bark using saline as solvent. The osmolality and pH of the extracts were adjusted to an adequate interaction with human cells. Red blood cells (RBCs) from healthy donors (n=3) were used and incubated with glucose solution for in vitro simulation of the hyperglycemia effects. RBCs were incubated with the aqueous extracts to assess their hemocompatibility. Also, glycated RBCs were incubated with the extracts to analyze their anti-diabetic properties. Erythrocyte Rheometer and Optical Chip Aggregameter were used for the hemorheological evaluation. Results: Assays with the different P. sellowianus extracts modified the viscoelasticity and aggregation of RBCs. Moreover, in some cases, P. sellowianus extracts reversed the in vitro glycation effect and hemorheological parameters got nearer control values. Conclusion: These results would be helpful for the development of pharmaceutical formulations using this species or its phytocomponents. They also give relevant information to understand the action mechanisms through which these extracts or their components can be used as anti-diabetics in Phytomedicine.
Acceso Abierto
Estudio preliminar del efecto de las radiaciones gamma sobre la concentración de iones plasmáticos en unidades transfusionales
(Asociación Física Argentina, 2024-03-28) Alet, Analía Inés; Porini, Sabrina; Detarsio, Germán; Aresi, Ariel; Di Tullio Budassi, Liliana; Manzelli, Nestor; Acosta, Andrea; Galassi, Mariel E.; Riquelme, Bibiana Doris
Los concentrados de glóbulos rojos son el componente que se utiliza con mayor frecuencia en las transfusiones sanguíneas. La irradiación gamma de la unidad transfusional está indicada cuando un paciente corre el riesgo de desarrollar la enfermedad de injerto contra huésped asociada a una transfusión. Sin embargo, esta irradiación exacerba la lesión de almacenamiento aumentando los niveles plasmáticos de potasio y disminuyendo los de sodio. Estos efectos sobre los glóbulos rojos reducen el tiempo de viabilidad de las unidades transfusionales irradiadas almacenadas. En este trabajo, estudiamos el efecto de diferentes dosis de radiación gamma sobre la concentración de los iones plasmáticos en las bolsas irradiadas, los cuales son indicativos de posibles alteraciones de las membranas de los glóbulos rojos y de los leucocitos. El análisis de los resultados obtenidos muestra que la radiación, a las dosis estudiadas, no afecta el consumo de glucosa. Sin embargo, la permeabilidad de la membrana de los eritrocitos aumenta con la dosis de radiación, indicando que este tipo de alteraciones podrían ser dosis dependiente. Estos resultados podrían ayudar a diseñar nuevos medios de conservación para reducir el daño a la membrana inducido por la radiación.
Acceso Abierto
Quinic acid and hypervalent chromium: a spectroscopic and kinetic study
(Royal Society of Chemistry, 2018-08-17) Mangiameli, María Florencia; Bellú, Sebastián; Pérez Mora, Bárbara; Sala, Luis Federico; Mamana, Nadia; https://orcid.org/0000-0002-6338-676X
The redox reaction between an excess of quinic acid (QA) and CrVI involves the formation of intermediates, namely, CrIV and CrV species, which in turn react with the organic substrates. As observed with other substrates that have already been studied, CrIV does not accumulate during this reaction because of the rate of the reaction. Its rate of disappearance is several times higher than that of the reaction of CrVI or CrV with QA. Kinetic studies indicate that the redox reaction proceeds via a combined mechanism that involves the pathways CrVI → CrIV → CrII and CrVI → CrIV → CrIII, which is supported by the observation of superoxo-CrIII (CrO22+) ions, free radicals, and oxo-CrV species as intermediates and the detection of CrVI ester species. The present study reports the complete rate laws for the QA/chromium redox reaction.
Acceso 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.
Acceso 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.
Acceso 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 ).
Acceso 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 Tullio, 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.
Acceso 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.
Acceso 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
Acceso 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.
Acceso 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
Acceso 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
Acceso Abierto
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.
Acceso 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
Acceso 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
Acceso 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.

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