Recent publications
A green and sustainable approach to the direct synthesis of thioesters has been developed using Fe3O4 as a low‐cost, easily prepared, reusable and environmentally safe catalyst. The cross dehydrogenative coupling (CDC) of various thiols and aldehydes in water, or even in the absence of solvent, using tert‐butylhydroperoxide as oxidant, under ligand and base‐free mild conditions, afforded the corresponding thioesters in good to excellent yields. This simple protocol features broad substrate scope, good compatibility with different functional groups, as well as high atom‐efficiency. The scalability, ease of (magnetic) recovery and reuse of the magnetite catalyst are additional eco‐friendly attributes of this methodology. Moreover, the broad synthetic applications of thioesters further highlight the potential utility of the present protocol.
The DAF-2/insulin/insulin-like growth factor signaling (IIS) pathway plays an evolutionarily conserved role in regulating reproductive development, life span, and stress resistance. In Caenorhabditis elegans, DAF-2/IIS signaling is modulated by an extensive array of insulin-like peptides (ILPs) with diverse spatial and temporal expression patterns. However, the release dynamics and specific functions of these ILPs in adapting to different environmental conditions remain poorly understood. Here, we show that the ILP, insulin-3 (INS-3), plays a crucial role in modulating the response to various environmental stressors in C. elegans. ins-3 mutants display increased resistance to heat, oxidative stress, and starvation; however, this advantage is countered by slower reproductive development under favorable conditions. We find that ins-3 expression is downregulated in response to environmental stressors, whereas, the neurohormone tyramine, which is released during the acute flight response, increases ins-3 expression. We show that tyramine induces intestinal calcium (Ca²⁺) transients through the activation of the TYRA-3 receptor. Our data support a model in which tyramine negatively impacts environmental stress resistance by stimulating the release of INS-3 from the intestine via the activation of a TYRA-3-Gαq-IP3 pathway. The release of INS-3 systemically activates the DAF-2 pathway, resulting in the inhibition of cytoprotective mechanisms mediated by DAF-16/FOXO. These studies offer mechanistic insights into a brain–gut communication pathway that weighs adaptive strategies to respond to acute and long-term stressors.
The present study evaluated the potential use of methanolic extracts from two seaweeds from the Argentine Patagonian coasts, Macrocystis pyrifera and Undaria pinnatifida, as natural alternatives against Paenibacillus larvae. We carried out a detailed characterization of both seaweeds, comparing vegetative and reproductive thallus portions. We also assessed their phenolic content and antioxidant activity and evaluated the in vitro antibacterial action. Based on the minimal inhibitory concentration results, extracts from sporophyll of Undaria (US) and basal thallus portion of Macrocystis (MB) are strong inhibitors. US showed the best activity against P. larvae strain CMM(B)35 (12.2 μg/mL), and MB showed the same activity for strains CMM(B)35 and MAR1 (18.6 μg/mL). Antioxidant activity was higher in US, followed by MB, and a positive correlation was found with phenolic content. Taken together, our results indicate the role of specific chemical compounds present in algal extracts on antioxidant properties and antibacterial activity against P. larvae. We conclude that these seaweeds are promising alternatives against P. larvae.
Alginate production is estimated to be around 30,000 tonnes per year, coming from a limited number of macroalgae species. Therefore, to diversify the market and make it sustainable over time, it is important to find new species that produce alginate. In this study, physicochemical characteristics and biological activity of alginate obtained from Punctaria latifolia were evaluated. An alginate yield of 17% (w/w) with a weight-average molar mass of ≈ 303 KDa, a polydispersity index of 1.6 and a M/G ratio of 1.09 was obtained. FT-IR spectra confirmed that the extracted polysaccharide had the characteristic of alginates and each extracted fraction showed the typical bands of MG, MM and GG blocks. Rheological properties of 0.1 N NaCl aqueous solutions of P. latifolia alginate showed that viscous modulus is higher than elastic one, and they presented a good emulsifying capacity against different food-grade oils and benzene. Also, P. latifolia alginate had an antioxidant capacity of 1.24 ± 0.1 mg AAEq g ⁻¹ alginate and showed antitumor effect on tumoral MCF-7 cells at concentrations of 1000 and 2000 µg mL⁻¹. On the other hand, P. latifolia alginate had no cytotoxic effects on non-tumor, osteoblastic (hFOB) and fibroblastic (NIH3T3) cell lines.
Identifying the changes that take place at the molecular, cellular, and neurocircuitry levels is of key importance to understanding the neurobiological mechanisms involved in drug addiction, currently considered a chronic neuropsychiatric disorder. Nicotinic acetylcholine receptors (nAChRs) are a Cys-loop gene family of neurotransmitter receptors belonging to the superfamily of pentameric ligand-gated cation channels. The neuronal-type nAChRs are expressed in mammalian brain, playing a critical role in various addictive disorders. The ample combinatorial diversity of nAChR subtypes explains the diversity of functional responses to different drugs and chemical compounds that these neurotransmitter receptors undergo in different brain regions.
Cannabis is increasingly becoming one of the most widespread addictive drugs, and its receptors in brain show macro- and microanatomical overlap with some subtypes of nAChRs. Cannabinoid receptors are important homeostatic modulators of neuronal activity in the central nervous system, and their interaction with nAChRs is not only anatomical but functional. Neuroadaptations, including the down- or upregulation of selective nAChR subtypes, the modulation of neurotransmitter release and neuronal scaffolding proteins, and the consequent strengthening or weakening of synapses form part of the varied palette of mechanisms involving the ubiquitous nAChR molecule in response to drug addiction, some of which imply crosstalk with cannabinoid receptors.
The relationship between land use and land cover (LULC) and water issues has been extensively studied. However, there is still a need to develop management strategies that effectively integrate both aspects at the local level. For this reason, this paper aims to identify opportunities and challenges for the integrated management of LULC and water resources in the district of Tornquist, Buenos Aires, Argentina. Using a mixed-methods approach, the research combines stakeholder analysis, social perception surveys, and participatory workshops to provide a comprehensive assessment of socio-institutional dynamics. Our findings reveal water and LULC management fragmentation across institutional and political levels. At the provincial and national levels, stakeholder connections are weaker than at the local level, requiring improved interactions and dialogue spaces involving all actors. Attention is predominantly on water availability rather than flooding. In both cases, the main cause of their changes was associated with the lack of water policies and infrastructure. The local community does not identify LULC changes as the main cause of variations in flooding and water availability but they recognize their relationship with water problems. Identifying, interpreting, and leveraging stakeholder relationships can contribute to the design of an integrated management strategy. By situating its analysis in a semiarid region with significant climatic and socio-environmental variability, the study provides actionable insights for similar contexts globally and underscores the critical need for inclusive, place-based solutions to address the growing pressures on land and water resources.
The interaction of Ni with (6,0) and (8,0) zigzag carbon nanotube exterior surfaces containing two vacancies was studied using density functional theory (DFT). A two-vacancy defect was analysed in order to anchor Ni, and the pristine nanotube was also considered as a reference for each chirality. The adsorbed Ni stability and the nanotube’s geometry and electronic structure were analysed before and after the adsorption. We compared calculations performed using a general gradient functional with those conducted using two semi-classical dispersion methods to assess the van der Waals forces (PBE-D2 and PBE-D3). In addition, the inclusion of the Hubbard parameter for the correction of Ni d electron self-interaction energy was included, and we evaluated energy and electronic structure changes through atomic-level calculations. Adsorption energy, the density of states, and the charge distribution were obtained to establish the Ni binding on the defective nanotube’s dominating mechanisms. The effect of curvature and applied functional influence was also considered. Furthermore, a bonding analysis was performed to complement our comprehension of the interaction between Ni and the nanotube surfaces. The electronic results show that Ni-doped two-vacancy (6,0) and (8,0) carbon nanotubes can be applied for the development of low-resistance contact materials and spintronic devices, respectively.
Access to health services is a multidimensional and multistage phenomenon. Despite the extensive development of the theoretical framework of access to health care, until now, no indices have been developed to measure all its dimensions and stages. In this work, we propose an index for measuring the multidimensional access to health services, considering nine dimensions of this phenomenon and a questionnaire format that allows obtaining information for its calculation and application. The proposed index is continuous, monotonic, and can be decomposed according to dimensions and services. At the same time, our index considers the subjectivity in the patient valuation of each dimension throughout the different stages of health access. As a case study, we applied the proposed methodology to a medium-sized city in Argentina, determining the relationship of the index with socioeconomic factors and its spatial distribution. Although no clear geographic pattern emerged from the results, statistically significant relationships were found with socioeconomic factors such as gender identity, educational level, activity status, and type of health insurance of the household head.
This paper proposes to combine full feedback linearization with full state feedback and trajectory tracking control in order to obtain a high performance dc-ac boost converter. The system is composed of a boost converter, an inverter and a power pulsation buffer, which removes the ripple from the dc-link, and allows reducing the size of its capacitor. This can improve the reliability of the system, as smaller capacitors do not need to be electrolytic. The use of full feedback linearization enables a stable controller at any point of operation, while the trajectory tracking control allows high performance tracking of the references (required for smaller capacitor values). The steady state performance and disturbance rejection capabilities are provided by the full state feedback control. Additionally, the effect of parametric mismatches is analyzed, and the robustness of the proposal is validated through simulations and experimental results
This paper proposes a solution for the self-synchronization of grid-tied feeding inverters. Since the proposed algorithm allows the self-synchronization, it avoids using a voltage sensor for measuring the Point of Common Coupling (PCC) voltage. The algorithm is based on an adaptive non-linear observer that uses the measurement of the output inductor current. Unlike synchronization schemes based on the virtual synchronous generator, which is often used in control strategies based on power synchronization, when combined with a non-linear control strategy, the proposed algorithm allows obtaining an excellent dynamic performance, even in presence of large PCC voltage disturbances and fast varying references. The performance of the proposed observer when combined with a non-linear control strategy, designed by considering the non-linear model of the converter, is illustrated through experimental results.
This article studies the interdependence between Argentina’s public over-indebtedness and climate change. It addresses the following questions: What type of productive model does the Argentine public debt profile promote, and what is its impact on climate change? In a debt-servicing scheme marked by fiscal consolidation, which strongly conditions the state budget, what public funds are available to invest in adaptation and mitigation? Finally, what is the role of the IMF in this fiscal-environmental scheme? The article first presents the international commitments of the Argentine State in the face of climate change and the estimated fiscal cost of implementing the necessary adaptation and mitigation measures. It then describes the situation of Argentina’s debt in historical perspective up to the present and explains how the external debt has been determining the productive specialization of the national economy, which seeks to boost the country’s primary export capacity, particularly agribusiness, the fossil fuel sector, and open-pit metalliferous mining. It also analyzes the role of the IMF in Argentina as a catalytic actor in the climate crisis, describing the IMF’s centrality in the national economy, its economic-environmental policy on the production pattern that accelerates climate change, and the incidence of this phenomenon in Argentina.
Plain Language Summary
The Earth's ionosphere presents long‐term trends besides regular changes such as daily and seasonal, and irregular variations of transient character. Many studies suggest that the long‐term increase in greenhouse gas concentrations will produce a global cooling in the upper atmosphere together with the global warming in the troposphere. Therefore, long‐term trends can be expected in the ionosphere total electron content (TEC), the critical frequency of the F2 layer, foF2, and its peak height, hmF2, which are the three most important ionospheric parameters used in several applications. TEC measurements have the advantage over other parameters that characterize the upper atmosphere having 24 × 365 worldwide coverage thanks to the continuous International GNSS service (IGS). Trends in the ionosphere are much weaker than those associated with the solar cycle, thus its effects were removed using different solar EUV radiation proxies. The trends are negative, as expected, not only for the mean global value case but also for most of the regional values with very few exceptions.
Marques (Philosophia,49(3), 1109–1125 2021) argues that Hom’s Combinatorial Externalism (CE) faces a hitherto unknown problem when coupled with a standard Kratzerian account of deontic modality: CE plus Kratzerian modality would entail the negation of a thesis central to Hom’s analysis of slurs, the null extensionality thesis (i.e., the thesis that slurs have empty extensions). Since modality is an integral part of Hom’s take on slurs, and Kratzer’s account of modality has the status of the standard take on modality, this would be bad news for CE. In this paper, I argue that, pace Marques, CE and a Kratzerian account of deontic modals do not clash with the null extensionality claim. Marques’ discussion, however, helps us expose substantive, non-semantic assumptions concerning practical philosophy that seem to be implicitly built into CE’s semantic analysis of slurs.
Hearing loss (HL) affects more than 5 % of the global population, with projections indicating an impact of up to 50 % on young individuals in the next years. HL treatments remain limited due to the inner ear's hermeticism. HL often involves inflammatory processes, underscoring the need for enhanced delivery of antiinflammatory agents to the inner ear. Our research focuses on the development of a directed therapy based on magnetic nanoparticles (MNPs). We previously synthesized biocompatible folic acid‐coated iron oxide‐core nanoparticles (MNPs@FA) as potential carriers for the anti‐inflammatory Diclofenac (Dfc). This study aims to incorporate Dfc onto MNPs@FA to facilitate targeted drug delivery to the inner ear. Through optimizing the loading procedure, we achieved optimal loading capacity. Dfc release was studied in the simulated target fluid and the administration vehicle. Complete characterization is also shown. In vitro biocompatibility testing ensured the biosafety of the resulting formulation. Subsequent ex vivo targeting assays on murine cochleae validated the nanosystems’ ability to penetrate the round window membrane, one of the main HL therapy barriers. These findings serve as validation before continuing to more complex in vivo studies. Together, the data here presented represent an advancement in addressing unmet medical needs in HL therapy.
Objetivo:
Debido al aumento en el consumo de alcohol entre la población juvenil y los potenciales riesgos físicos y mentales que esta situación provoca, este trabajo analiza los factores que condicionan el consumo excesivo de alcohol en adolescentes de 13 a 17 años en Argentina.
Materiales y métodos:
Se utilizan datos de la Encuesta Mundial de Salud Escolar, aplicada a una muestra representativa de 56,981 adolescentes en todo el país en 2018. Se estiman modelos logísticos que toman en cuenta el rol de factores personales, socioeconómicos, psicológicos y situacionales A la vez, se analiza el impacto que el consumo excesivo de alcohol tiene sobre conductas de riesgo y sobre daños sufridos por adolescentes.
Resultados:
Se observó un incremento en el consumo de alcohol entre adolescentes, con una mayor incidencia en mujeres. Los factores situacionales, como la disponibilidad de alcohol y la presión de pares, son determinantes clave. Existe una fuerte asociación entre el consumo excesivo de alcohol y las conductas de riesgo, así como un aumento en los daños sufridos por los adolescentes.
Conclusiones:
Se subraya la necesidad de implementar medidas reguladoras y protectoras específicas. La importancia de estrategias integrales de prevención y educación es destacada, enfocándose en los factores situacionales y sociales. Las intervenciones deben involucrar a familia, escuela y comunidad para reducir los riesgos y promover comportamientos saludables.
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