Sindicador de canales de noticias
Nanostructured amorphous gallium phosphide on silica for nonlinear and ultrafast nanophotonics
Tilmann, Benjamin; Grinblat, Gustavo Sergio; Berté, Rodrigo; Özcan, Mehmet; Kunzelmann, Viktoria F.; Nickel, Bert; Sharp, Ian D.; Cortés, Emiliano; Maier, Stefan A.; Li, Yi
Nanophotonics based on high refractive index dielectrics relies on appreciable contrast between the indices of designed nanostructures and their immediate surrounding, which can be achieved by the growth of thin films on low-index substrates. Here we propose the use of high index amorphous gallium phosphide (a-GaP), fabricated by radio-frequency sputter deposition, on top of a low refractive index glass substrate and thoroughly examine its nanophotonic properties. Spectral ellipsometry of the amorphous material demonstrates the optical properties to be considerably close to crystalline gallium phosphide (c-GaP), with low-loss transparency for wavelengths longer than 650 nm. When nanostructured into nanopatches, the second harmonic (SH) response of an individual a-GaP patch is characterized to be more than two orders of magnitude larger than the as-deposited unstructured film, with an anapole-like resonant behavior. Numerical simulations are in good agreement with the experimental results over a large spectral and geometrical range. Furthermore, by studying individual a-GaP nanopatches through non-degenerate pump-probe spectroscopy with sub-10 fs pulses, we find a more than 5% ultrafast modulation of the reflectivity that is accompanied by a slower decaying free carrier contribution, caused by absorption. Our investigations reveal a potential for a-GaP as an adequate inexpensive and CMOS-compatible material for nonlinear nanophotonic applications as well as for photocatalysis.
Effect of pilot-scale UV-C light treatment assisted by mild heat on E. coli, L. plantarum and S. cerevisiae inactivation in clear and turbid fruit juices: Storage study of surviving populations
Effect of pilot-scale UV-C light treatment assisted by mild heat on E. coli, L. plantarum and S. cerevisiae inactivation in clear and turbid fruit juices: Storage study of surviving populations
Fenoglio, Daniela; Ferrario, Mariana Inés; Schenk, Marcela Liliana; Guerrero, Sandra N.
Consumer growing demands for high-quality and safe food and beverages have stimulated the interest in alternative preservation technologies. Short-wavelength ultraviolet light (UV-C, 254 nm) has proven to be useful for the decontamination of a great variety of clear juices while improving their quality compared to traditional thermal treatments. Suspended solids and coloured compounds in turbid juices, diminish light transmission. The use of UV-C under a hurdle approach, may be a promising strategy for their treatment. The purpose of this study was to analyse Escherichia coli ATCC 25922, Saccharomyces cerevisiae KE 162 and Lactobacillus plantarum ATCC 8014 inactivation in clear pear juice (PJ), turbid orange-tangerine (OT) and orange-banana-mango-kiwi-strawberry (OBMKS) juices processed by single UV-C (390 mJ/cm2, 20 °C) and UV-C assisted by mild heat (UV-C/H, 50 °C) at pilot-scale in a coiled tubing unit and stored under refrigeration (5 °C). Inactivation studies were also conducted in peptone water (PW) and model solution (MS). The adequacy of the Coroller, Weibull and Biphasic Plus Shoulder models was studied. UV-C was highly effective in PW, MS and PJ, achieving up to 5.5-6.3-4.7, 4.8-5.1-4.6 and 4.4-5.5 log reductions for L. plantarum, E. coli,and S. cerevisiae, respectively. Whereas, a moderate inactivation by single UV-C was recorded in the turbid blends, reducing up to 2.4-3.8-1.6 and 3.6-3.7-1.3 log-cycles in OT and OBMKS, respectively. When the UV-C/H treatment was applied, high bacterial inactivation was observed achieving 5.2-5.6, 6.3-6.6 and 5.5-6.7 log reductions in OT, OBMKS and PJ, respectively, while 4.6-4.9 log reductions were determined for the yeast in OBMKS and OT, respectively. Thus, additive inactivation effects between UV-C and H were observed. All the models tested gave useful information regarding the existence of microbial subpopulations with varying resistances. However, the cumulative Weibull distribution function was the most versatile one, fitting inactivation curves with different shapes. Additionally, the frequency distributions of resistances showed that UV-C/H not only increased the UV-C microbicidal effect but changed the distribution of inactivation times. Principal component analysis revealed that UV-C effectiveness was associated to low particle size, a⃰, turbidity and high UV-C transmittance. An increase on the inactivation of treated bacterial populations was recorded along storage, while no yeast recovery was observed, thus emphasizing the contribution of refrigerated storage to microbial inactivation. Microbial inactivation in clear and turbid juices achieved by UV-C (390 mJ/cm2) assisted by mild heat (50 °C) and subsequent refrigerated storage may represent an useful alternative for multiple applications in the juice industry.
Through the looking-glass with ALICE into the quark-gluon plasma: A new test for hadronic interaction models used in air shower simulations
Through the looking-glass with ALICE into the quark-gluon plasma: A new test for hadronic interaction models used in air shower simulations
Anchordoqui, Luis A.; García Canal, Carlos Alberto; Sciutto, Sergio Juan; Soriano, Jorge F.
Recently, the ALICE Collaboration reported an enhancement of the yield ratio of strange and multi-strange hadrons to charged pions as a function of multiplicity at mid-rapidity in proton-proton, proton-lead, lead-lead, and xenon-xenon scattering. ALICE observations provide a strong indication that a quark-gluon plasma is partly formed in high multiplicity events of both small and large colliding systems. Motivated by ALICE’s results, we propose a new test for hadronic interaction models used for analyzing ultra-highenergy-cosmic-ray (UHECR) collisions with air nuclei. The test is grounded in the almost equal columnenergy density in UHECR-air collisions and lead-lead collisions at the LHC. We applied the test to postLHC event generators describing hadronic phenomena of UHECR scattering and show that these QCD Monte Carlo-based codes must be retuned to accommodate the strangeness enhancement relative to pions observed in LHC data.
Territorios de expansión y espacio urbano: el caso de los corredores litorales del Gran Santa Fe (1980-2018)
Territorios de expansión y espacio urbano: el caso de los corredores litorales del Gran Santa Fe (1980-2018)
Szupiany, Estefanía Belén
La forma lineal de expansión en torno a vías de circulación vehicular se convirtió en uno de los patrones dominantes del crecimiento urbano contemporáneo. Devenida en objeto de estudio, nos referimos a esta forma lineal bajo la denominación de Corredores de Expansión Urbana, en tanto unidades espaciales de investigación histórica y prospectiva. El objetivo de este artículo consiste en echar luz sobre este modo particular de habitar lo urbano, el cual se traduce en prácticas de sociabilidad conflictivas experimentadas por las comunidades allí establecidas. Para ello, se analiza el caso de una ciudad media de América Latina (Santa Fe, Argentina), cuyo crecimiento adquirió formas lineales en un entorno fluvial complejo. Se parte de un posicionamiento teórico y conceptual que propone revisar la noción de espacio urbano, para luego examinar -a la luz de esta mirada renovada- el caso de estudio propuesto; en particular, sus Corredores Litorales. Las discusiones finales apuntan a develar las causas de los conflictos detectados y a considerar los desafíos que estos nuevos modos de habitar el territorio plantean a la planificación urbana.; The linear form of expansion along vehicular roads became one of the dominant patterns of contemporary urban expansion. As an object of study, we refer to this linear form as Urban Expansion Corridors, as historical and prospective research units. The aim of this article is to clarify this particular way of inhabiting the city, by examining the materialization of the built environment along with the failures of urban public policy and its challenges To this end, we analyse the case of an intermediate Latin American city (Santa Fe, Argentina), whose growth acquired linear forms in a complex fluvial environment. The starting point is a theoretical and conceptual positioning that proposes to revisit the notion of urban space, to then examine –from this renewed perspective– the proposed case study; in particular its Littoral Corridors. The discussions aim to problematize the interventions –especially in the road sector– of urban public policies in the spatial configuration of CEU, as well as to consider the challenges that these new ways of inhabiting the territory present to urban planning.; A forma linear de expansão em torno das estradas de veículos converteu-se num dos padrões dominantes do crescimento urbano contemporâneo. Tornando-se um objeto de estudo, referimo-nos a esta forma linear como Corredores de Expansão Urbana, enquanto unidades espaciais de investigação histórica e prospectiva. O objetivo deste artigo é esclarecer esta forma particular de habitar a cidade, examinando a materialização do ambiente construído juntamente com os insucessos das políticas públicas urbanas e os seus desafios. Para isso, analisamos o caso de uma cidade média latino-americana (Santa Fé, Argentina), cujo crescimento adquiriu formas lineares em um ambiente fluvial complexo. O ponto de partida é um posicionamento teórico e conceptual que propõe a revisão da noção de espaço urbano, para mais tarde examinar –à luz deste olhar renovado– o estudo de caso proposto; em particular, os seus Corredores Litorais. As discussões visam problematizar as intervenções –especialmente no campo rodoviário– das políticas públicas urbanas na configuração espacial da CEU, bem como considerar os desafios que estas novas formas de habitar o território impõem ao planeamento urbano.
Mitochondrial genetic differentiation and phylogenetic relationships of three Eptesicus (Histiotus) species in a contact zone in Patagonia
Mitochondrial genetic differentiation and phylogenetic relationships of three Eptesicus (Histiotus) species in a contact zone in Patagonia; Diferenciación genética mitocondrial y relaciones filogenéticas entre tres especies de Eptesicus (Histiotus) en una zona de contacto en la Patagonia.
Giménez, Analía Laura; Giannini, Norberto Pedro; Cunha Almeida, Francisca
Eptesicus (Histiotus) magellanicus is a relatively rare and poorly known Patagonian endemic. This species is currently recognized as a valid, butuntil recently some authors treated it as a subspecies of E. (H.) montanus. In fact, nomolecular data exist to support the distinctiveness of the former. In Patagonia, the distribution of these two speciesoverlap marginally; they are also sympatric with a third Histiotus species,E. (H.) macrotus. In this study, we present for the _rsttime molecular data that corroborate morphological evidence of the separationbetween E. (H.) magellanicus from other Eptesicus (Histiotus)species, in special the ones with which it shares its distribution. Wesequenced a nuclear intron (THY) and thecytochrome b (Cyt b) gene from specimens of E. (H.) magellanicus, E. (H.) montanus, and E. (H.) macrotus, collected in theChubut Province (Argentina), and from an undescribed Eptesicus (Histiotus)species from Peru. We included these sequences in a phylogenetic analysistogether with previously published sequences of four typical Eptesicus species. The THY intron showed very little variation, while the Cyt b phylogeny recovered three highly supported Histiotus clades. A highly supported clade comprising all specimens of E. (H.) magellanicus was the _rst to split o_ Histiotus,suggesting that the Andean region was important during the early diversi_cationof the genus. Unexpectedly, the clade containing the specimens of E. (H.) macrotus and E. (H.) montanus showed no internal resolution, eitherquestioning their mutualidentity as a separate species, or suggesting the occurrence of localhybridization and introgression.; Eptesicus (Histiotus) magellanicus es una especie endémica de Patagonia, relativamente rara y pobremente conocida. Actualmente Eptesicus (Histiotus) magellanicus es reconocida como especie válida; sin embargo, recientemente ha sido considerada como subespecie de Eptesicus (H.) montanus por algunos autores. En Patagonia estas dos especies solapan sus distribuciones marginalmente, donde además son simpátricas con una tercera especie, Eptesicus (H.) macrotus. En este estudio presentamos por primera vez datos moleculares que corroboran la evidencia morfológica que diferencian a E. (H.) magellanicus del resto de las especies de Histiotus, en especial con aquellas con las que comparte su distribución. Se secuenciaron un intron del gen de la tirotropina y gen citocromo b para especímenes de E. (H.) magellanicus, E. (H.) montanus, y E. (H.) macrotus, colectados en la provincia del Chubut (Argentina), y dos ejemplares de Eptesicus (H.) sp. de Perú. Analizamos sus secuencias junto con otras previamente publicadas para cuatro especies típicas de Eptesicus. El gen tirotropina mostró muy poca variación, mientras que la filogenia obtenida con el gen citocromo b recuperó tres clados de Histiotus fuertemente soportados. El clado que incluyó a todos los especímenes de E. (H.) magellanicus fue el primero en separarse dentro de Histiotus, sugiriendo que la región andina fue importante durante la diversificación temprana del género. Inesperadamente, el clado que contenía las muestras de E. (H.) macrotus y de E. (H.) montanus no mostró resolución interna, sugiriendo dos posibles alternativas, la existencia de una única especie o la ocurrencia de hibridación e introgresión local.
Praxelis clematidea (Asteraceae, eupatorieae, praxelinae) en Uruguay: Primer registro del género y la especie
Praxelis clematidea (Asteraceae, eupatorieae, praxelinae) en Uruguay: Primer registro del género y la especie; Praxelis clematidea (Asteraceae,eupatorieae,praxelinae) in Uruguay: First record of the genus and the species
Salgado, Vanina Gabriela; Grossi, Mariana Andrea; González, Andrés H.; Gutierrez, Diego Germán
Durante la revisión de las especies del género Praxelis de Sudamérica meridional, poblaciones de P. clematidea fueron halladas en el noroeste de Uruguay. En este trabajo proporcionamos el primer registro del género y la especie para la flora Uruguaya junto con un análisis taxonómico y morfológico basado en ejemplares de herbario y observaciones de campo. Además, se presentan los usos de P. clematidea, su distribución y hábitat, nombres comunes, una ilustración y una clave para diferenciar las especies de Praxelis de Uruguay y áreas circundantes de Argentina y Brasil.; During the revision of the southern South American species of Praxelis, populations of P. clematidea were found in northwestern Uruguay. In this study, we provide the first record of the genus and the species for the Uruguayan flora, along with taxonomic and morphological analyses based on herbarium specimens and field observations. In addition, uses of P. clematidea, its distribution and habitat, common names, an illustration and a key to differentiate the species of Praxelis of Uruguay and surrounding areas of Argentina and Brazil are presented.
Hierarchical Multivalent Effects Control Influenza Host Specificity
Hierarchical Multivalent Effects Control Influenza Host Specificity
Overeem, Nico J.; Hamming, P. H. Erik; Grant, Oliver C.; Di Iorio, Daniele; Tieke, Malte; Bertolino, María Candelaria; Li, Zeshi; Vos, Gaël; de Vries, Robert P.; Woods, Robert J.; Tito, Nicholas B.; Boons, Geert-Jan P. H.; van der Vries, Erhard; Huskens, Jurriaan
Understanding how emerging influenza viruses recognize host cells is critical in evaluating their zoonotic potential, pathogenicity, and transmissibility between humans. The surface of the influenza virus is covered with hemagglutinin (HA) proteins that can form multiple interactions with sialic acid-terminated glycans on the host cell surface. This multivalent binding affects the selectivity of the virus in ways that cannot be predicted from the individual receptor-ligand interactions alone. Here, we show that the intrinsic structural and energetic differences between the interactions of avian- or human-type receptors with influenza HA translate from individual site affinity and orientation through receptor length and density on the surface into virus avidity and specificity. We introduce a method to measure virus avidity using receptor density gradients. We found that influenza viruses attached stably to a surface at receptor densities that correspond to a minimum number of approximately 8 HA-glycan interactions, but more interactions were required if the receptors were short and human-type. Thus, the avidity and specificity of influenza viruses for a host cell depend not on the sialic acid linkage alone but on a combination of linkage and the length and density of receptors on the cell surface. Our findings suggest that threshold receptor densities play a key role in virus tropism, which is a predicting factor for both their virulence and zoonotic potential.
Breaking Simple Scaling Relations through Metal-Oxide Interactions: Understanding Room-Temperature Activation of Methane on M/CeO2(M = Pt, Ni, or Co) Interfaces
Breaking Simple Scaling Relations through Metal-Oxide Interactions: Understanding Room-Temperature Activation of Methane on M/CeO2(M = Pt, Ni, or Co) Interfaces
Lustemberg, Pablo German; Zhang, Feng; Gutiérrez, Ramón A.; Ramírez, Pedro J.; Senanayake, Sanjaya D.; Rodriguez, José A.; Ganduglia Pirovano, Maria Veronica
The clean activation of methane at low temperatures remains an eminent challenge and a field of competitive research. In particular, on late transition metal surfaces such as Pt(111) or Ni(111), higher temperatures are necessary to activate the hydrocarbon molecule, but a massive deposition of carbon makes the metal surface useless for catalytic activity. However, on very low-loaded M/CeO2 (M = Pt, Ni, or Co) surfaces, the dissociation of methane occurs at room temperature, which is unexpected considering simple linear scaling relationships. This intriguing phenomenon has been studied using a combination of experimental techniques (ambient-pressure X-ray photoelectron spectroscopy, time-resolved X-ray diffraction, and X-ray absorption spectroscopy) and density functional theory-based calculations. The experimental and theoretical studies show that the size and morphology of the supported nanoparticles together with strong metal-support interactions are behind the deviations from the scaling relations. These findings point toward a possible strategy for circumventing scaling relations, producing active and stable catalysts that can be employed for methane activation and conversion.
Development and validation of a mechanistic model for the release of embelin from a polycaprolactone matrix
Development and validation of a mechanistic model for the release of embelin from a polycaprolactone matrix
Seoane, Irene Teresita; Cortez Tornello, Pablo Roberto; Silva, Leonel Ignacio; Tomba, Juan Pablo; Abraham, Gustavo Abel; Cisilino, Adrian Pablo
Embelin is a natural agent with antimicrobial, antifungal and analgesic activities. This work presents a mechanistic model for the release of embelin from a polycaprolactone matrix. Based on the results of embelin release experiments and Raman microscopy measurements, the model assumes a dual dispersion of the embelin: agglomerated and dispersed. Embelin release mechanism combines the effects of the liquid migration into the matrix, the drug diffusion, and the drug dissolution within the wetted matrix. The model is formulated in terms of four partial differential equations that account for the mass balances of dispersed, agglomerated, and dissolved embelin, and aqueous solution. Model predictions show that the release mechanism involves three stages: a burst stage, in which dispersed embelin is rapidly released; a transition stage, in which dispersed and agglomerated embelin are simultaneously released; and, once the dispersed embelin depletion, a stable release stage until the agglomerated embelin exhausts.
Uterotonic agents for first-line treatment of postpartum haemorrhage: a network meta-analysis
Uterotonic agents for first-line treatment of postpartum haemorrhage: a network meta-analysis
Parry Smith, William R.; Papadopoulou, Argyro; Thomas, Eleanor; Tobias, Aurelio; Price, Malcolm J.; Meher, Shireen; Alfirevic, Zarko; Weeks, Andrew D.; Hofmeyr, G. Justus; Gülmezoglu, Ahmet Metin; Widmer, Mariana; Oladapo, Olufemi T.; Vogel, Joshua P.; Althabe, Fernando; Coomarasamy, Arri; Gallos, Ioannis D.
Background: Postpartum haemorrhage (PPH), defined as a blood loss of 500 mL or more after birth, is the leading cause of maternal death worldwide. The World Health Organization (WHO) recommends that all women giving birth should receive a prophylactic uterotonic agent. Despite the routine administration of a uterotonic agent for prevention, PPH remains a common complication causing one-quarter of all maternal deaths globally. When prevention fails and PPH occurs, further administration of uterotonic agents as 'first-line' treatment is recommended. However, there is uncertainty about which uterotonic agent is best for the 'first-line' treatment of PPH. Objectives: To identify the most effective uterotonic agent(s) with the least side-effects for PPH treatment, and generate a meaningful ranking among all available agents according to their relative effectiveness and side-effect profile. Search methods: We searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (5 May 2020), and the reference lists of all retrieved studies. Selection criteria: All randomised controlled trials or cluster-randomised trials comparing the effectiveness and safety of uterotonic agents with other uterotonic agents for the treatment of PPH were eligible for inclusion. Data collection and analysis: Two review authors independently assessed all trials for inclusion, extracted data and assessed each trial for risk of bias. Our primary outcomes were additional blood loss of 500 mL or more after recruitment to the trial until cessation of active bleeding and the composite outcome of maternal death or severe morbidity. Secondary outcomes included blood loss-related outcomes, morbidity outcomes, and patient-reported outcomes. We performed pairwise meta-analyses and indirect comparisons, where possible, but due to the limited number of included studies, we were unable to conduct the planned network meta-analysis. We used the GRADE approach to assess the certainty of evidence. Main results: Seven trials, involving 3738 women in 10 countries, were included in this review. All trials were conducted in hospital settings. Randomised women gave birth vaginally, except in one small trial, where women gave birth either vaginally or by caesarean section. Across the seven trials (14 trial arms) the following agents were used: six trial arms used oxytocin alone; four trial arms used misoprostol plus oxytocin; three trial arms used misoprostol; one trial arm used Syntometrine® (oxytocin and ergometrine fixed-dose combination) plus oxytocin infusion. Pairwise meta-analysis of two trials (1787 participants), suggests that misoprostol, as first-line treatment uterotonic agent, probably increases the risk of blood transfusion (risk ratio (RR) 1.47, 95% confidence interval (CI) 1.02 to 2.14, moderate-certainty) compared with oxytocin. Low-certainty evidence suggests that misoprostol administration may increase the incidence of additional blood loss of 1000 mL or more (RR 2.57, 95% CI 1.00 to 6.64). The data comparing misoprostol with oxytocin is imprecise, with a wide range of treatment effects for the additional blood loss of 500 mL or more (RR 1.66, 95% CI 0.69 to 4.02, low-certainty), maternal death or severe morbidity (RR 1.98, 95% CI 0.36 to 10.72, low-certainty, based on one study n = 809 participants, as the second study had zero events), and the use of additional uterotonics (RR 1.30, 95% CI 0.57 to 2.94, low-certainty). The risk of side-effects may be increased with the use of misoprostol compared with oxytocin: vomiting (2 trials, 1787 participants, RR 2.47, 95% CI 1.37 to 4.47, high-certainty) and fever (2 trials, 1787 participants, RR 3.43, 95% CI 0.65 to 18.18, low-certainty). According to pairwise meta-analysis of four trials (1881 participants) generating high-certainty evidence, misoprostol plus oxytocin makes little or no difference to the use of additional uterotonics (RR 0.99, 95% CI 0.94 to 1.05) and to blood transfusion (RR 0.95, 95% CI 0.77 to 1.17) compared with oxytocin. We cannot rule out an important benefit of using the misoprostol plus oxytocin combination over oxytocin alone, for additional blood loss of 500 mL or more (RR 0.84, 95% CI 0.66 to 1.06, moderate-certainty). We also cannot rule out important benefits or harms for additional blood loss of 1000 mL or more (RR 0.76, 95% CI 0.43 to 1.34, moderate-certainty, 3 trials, 1814 participants, one study reported zero events), and maternal mortality or severe morbidity (RR 1.09, 95% CI 0.35 to 3.39, moderate-certainty). Misoprostol plus oxytocin increases the incidence of fever (4 trials, 1866 participants, RR 3.07, 95% CI 2.62 to 3.61, high-certainty), and vomiting (2 trials, 1482 participants, RR 1.85, 95% CI 1.16 to 2.95, high-certainty) compared with oxytocin alone. For all outcomes of interest, the available evidence on the misoprostol versus Syntometrine® plus oxytocin combination was of very low-certainty and these effects remain unclear. Although network meta-analysis was not performed, we were able to compare the misoprostol plus oxytocin combination with misoprostol alone through the common comparator of oxytocin. This indirect comparison suggests that the misoprostol plus oxytocin combination probably reduces the risk of blood transfusion (RR 0.65, 95% CI 0.42 to 0.99, moderate-certainty) and may reduce the risk of additional blood loss of 1000 mL or more (RR 0.30, 95% CI 0.10 to 0.89, low-certainty) compared with misoprostol alone. The combination makes little or no difference to vomiting (RR 0.75, 95% CI 0.35 to 1.59, high-certainty) compared with misoprostol alone. Misoprostol plus oxytocin compared to misoprostol alone are compatible with a wide range of treatment effects for additional blood loss of 500 mL or more (RR 0.51, 95% CI 0.20 to 1.26, low-certainty), maternal mortality or severe morbidity (RR 0.55, 95% CI 0.07 to 4.24, low-certainty), use of additional uterotonics (RR 0.76, 95% CI 0.33 to 1.73, low-certainty), and fever (RR 0.90, 95% CI 0.17 to 4.77, low-certainty). Authors' conclusions: The available evidence suggests that oxytocin used as first-line treatment of PPH probably is more effective than misoprostol with less side-effects. Adding misoprostol to the conventional treatment of oxytocin probably makes little or no difference to effectiveness outcomes, and is also associated with more side-effects. The evidence for most uterotonic agents used as first-line treatment of PPH is limited, with no evidence found for commonly used agents, such as injectable prostaglandins, ergometrine, and Syntometrine®.
A first assessment of the land management effect on the ecological role of large trees as habitat refuges for desert small mammals
A first assessment of the land management effect on the ecological role of large trees as habitat refuges for desert small mammals
Szymañski, Carolina; Alvarez, Juan Agustin; Campos, Claudia Monica; Tabeni, Maria Solana
Large old trees are keystone organisms that generate a highly connected network of interactions because they provide refuge and feeding sites to mammals with different habitat requirements through their under canopy structure and deadwood. In dry woodlands, these keystone trees are found within agricultural landscapes, where grazing and deadwood removal are the mainsubsistence activities carried out by local people. These activities can modify the structure of trees and, in turn, affect small mammal communities. Our objective was to assess how different land management types modify the structure of P. flexuosa trees, and to determine the effects of modified tree structure on the abundance and composition of small mammal communities. The study was conducted in P. flexuosa forests within a protected area and in grazing fields. We found that the trees and the vegetation structure beneath their canopies reflect the management history of areas. Trees in the protected area and in an abandoned field were structurally more similar to one another than were those in grazing fields with deadwood removal and, in turn, presented greater total abundances of small mammals. Under tree canopy, the amount of deadwood and grass cover favor the presence of species that need closed and more complex habitats. Also, protection provided by the trees was differentially perceived by species, according to their ecological requirements. We can conclude that different land management scenarios allow for the conservation of the whole rodent assemblage and that, the trees determine the presence of species, particularly of those needing more complex habitats.
Public sector workers' mental health in Argentina: Comparative psychometrics of the perceived stress scale
Public sector workers' mental health in Argentina: Comparative psychometrics of the perceived stress scale
Miranda, Agustín Ramiro; Scotta, Ana Veronica; Méndez, Ana Lucía; Serra, Silvana Valeria; Soria, Elio Andres
Given that Argentinian public-sector workers are highly exposed to stressful conditions, and that the psychometric properties of the widely used Perceived Stress Scale (PSS) should be evaluated in different settings, this work aimed to compare the psychometric properties of the Latin American Spanish PSS-10 and PSS-4 and to identify the optimal scale for stress assessment. Methods: A sample of 535 participants was randomly divided into 2 groups to evaluate dimensionality by exploratory and confirmatory factor analyses. The reliability of both scales was also evaluated. Convergent validity was estimated using the Executive Complaints Questionnaire, the average variance extracted, and the composite reliability. Discriminant validity was based on the correlation with the Utrecht Work Engagement Scale and the phi-square correlation between the components. Results: The factor analyses supported bidimensionality of the PSS-10 (stress and coping), which showed a better fit than the PSS-4. Moreover, the reliability of the PSS-10 was higher, whereas the PSS-4 did not achieve adequate values of internal consistency. The PSS-10 was also correlated significantly with all validation scales, and presented proper internal convergent and divergent validity. Conclusions: The PSS-10 is a reliable and structurally valid instrument to measure perceived stress and coping in a Latin American Spanish-speaking population with high work demands, and the findings of this study expand our knowledge on the geographical and sociocultural applicability of the PSS.
Environmental Education as a Means for Valuing and Conserving Camelids and Pastoralism in the Argentinean Altiplano of Jujuy
Environmental Education as a Means for Valuing and Conserving Camelids and Pastoralism in the Argentinean Altiplano of Jujuy
Vila, Bibiana Leonor; Arzamendia, Yanina; Rojo, Veronica
Andean pastoralism, like other pastoral systems around the world, is under stress due to climate change, land tenure regimes, pressures to become sedentary, difficulties in interacting with market-based economies, isolation, and youth emigration. Over the years, we have proposed different environmental education (EE) strategies targeting local Andean stakeholders and university students, including interventions in primary schools. This paper presents the results of 4 EE interventions focusing on mountain environments, their biodiversity, environmental calendars, and llama caravans. School children participated creatively in this process by writing poems, drawing, and playing. The resulting work showed sensitivity, experiential knowledge, and a comprehensive vision of the environment. Most of the artworks were printed and disseminated in the children's local communities, where they are highly appreciated. We recognize that the usefulness of EE is constrained by social and economic pressures, including extractive activities. However, we also underscore its huge potential to guarantee sustainability during the inevitable process of change in traditional Andean pastoralism.
Creativos, divertidos, emprendedores y meritocráticos: El trabajo en contexto de las tecnologías de la información
Creativos, divertidos, emprendedores y meritocráticos: El trabajo en contexto de las tecnologías de la información; Creatives, fun, entrepreneurs and meritocratic: Work in the context of information technologies; Criativos, engraçados, empreendedores e meritocráticos: O trabalho no contexto das tecnologias da informação
Palermo Haber, Hernán Manuel; Ventrici, Patricia
El propósito del presente artículo es analizar la fuerza de trabajo que se produce y reproduce en un contexto laboral signado por la tecnología digital, en particular, en la empresa estrella en e-commerce de Latinoamérica: Mercado Libre. Específicamente, nos interesa abordar las significaciones acerca del trabajo que realizan los trabajadores y las trabajadoras, comprendiendo que estas se encuentran en una tensión constante entre las políticas empresarias, los procesos de pedagógicos de producción de una determinada fuerza de trabajo y las agencias de los sujetos. En este espacio laboral, el emprendedurismo y la meritocracia se perfilan como los sentidos dominantes en relación con la idea trabajo. Asimismo, indagamos las tensiones que se suscitan en la construcción gremial: sus desafíos, estrategias y limitaciones en una empresa donde la construcción managerial normativiza una noción de individuo como primera y última finalidad.; This article aims to analyze the work force that is produced and reproduced in a labor context marked by digital technology. In particular, we focus on the leading e-commerce company in Latin America: Mercado Libre. Specifically, we are interested in addressing worker’s meanings about work, understanding that they are in constant tension between business policies, business pedagogical processes and the agency of subjects. In this workspace, entrepreneurship and meritocracy emerge as the dominant meanings in relation to the idea of work. Likewise, we examine the tensions that arise in union construction: its challenges, strategies and limitations in a company where managerial construction standardizes a notion of the individual as the first and last purpose.; O objetivo deste artigo é analisar a força de trabalho que é produzida e reproduzida em um contexto de trabalho marcado pela tecnologia digital, em particular, na principal empresa de comércio eletrônico da América Latina: o “Mercado Libre”. Especificamente, estamos interessados em abordar os significados sobre o trabalho que os funcionários fazem, entendendo que eles estão em constante tensão entre as políticas de negócios, os processos pedagógicos de produção de uma determinada força de trabalho e os próprias agências. Neste espaço de trabalho o empreendedorismo e a meritocracia estão emergindo como os sentidos dominantes em relação à ideia de trabalho. Da mesma forma, investigamos as tensões que surgem na construção do sindicato: seus desafios, estratégias e limitações em uma empresa onde a construção gerencial padroniza a noção do indivíduo como primeira e última finalidade.
Adhesins of Brucella: Their Roles in the Interaction with the Host
Adhesins of Brucella: Their Roles in the Interaction with the Host
Bialer, Magali Graciela; Sycz, Gabriela; Muñoz González, Florencia; Ferrero, Mariana Cristina; Baldi, Pablo Cesar; Zorreguieta, Ángeles
A central aspect of Brucella pathogenicity is its ability to invade, survive, and replicate in diverse phagocytic and non-phagocytic cell types, leading to chronic infections and chronic inflammatory phenomena. Adhesion to the target cell is a critical first step in the invasion process. Several Brucella adhesins have been shown to mediate adhesion to cells, extracellular matrix components (ECM), or both. These include the sialic acid-binding proteins SP29 and SP41 (binding to erythrocytes and epithelial cells, respectively), the BigA and BigB proteins that contain an Ig-like domain (binding to cell adhesion molecules in epithelial cells), the monomeric autotransporters BmaA, BmaB, and BmaC (binding to ECM components, epithelial cells, osteoblasts, synoviocytes, and trophoblasts), the trimeric autotransporters BtaE and BtaF (binding to ECM components and epithelial cells) and Bp26 (binding to ECM components). An in vivo role has also been shown for the trimeric autotransporters, as deletion mutants display decreased colonization after oral and/or respiratory infection in mice, and it has also been suggested for BigA and BigB. Several adhesins have shown unipolar localization, suggesting that Brucella would express an adhesive pole. Adhesin-based vaccines may be useful to prevent brucellosis, as intranasal immunization in mice with BtaF conferred high levels of protection against oral challenge with B. suis.
Helminths from Sigmodontinae rodents (Muroidea: Cricetidae) in Humid Chaco ecoregion (Argentina): A list of species, host and geographical distribution
Helminths from Sigmodontinae rodents (Muroidea: Cricetidae) in Humid Chaco ecoregion (Argentina): A list of species, host and geographical distribution; Helmintos de roedores Sigmodontinae (Muroidea: Cricetidae) en la ecorregión del Chaco Húmedo (Argentina): lista de especies, hospedadores y distribución geográfica
Gómez Muñoz, María de Los Ángeles; Robles, Maria del Rosario; Milano, Alicia María Francisca; Digiani, Maria Celina; Notarnicola, Juliana; Galliari, Carlos Alberto; Navone, Graciela Teresa
Los objetivos de este trabajo fueron presentar una lista de helmintos de especies de roedores simpátricos (Muroidea, Cricetidae) de la ciudad de Corrientes, ecorregión del Chaco Húmedo, Argentina, y recopilar registros y datos ecológicos de las especies hospedadoras. Catorce especies de helmintos fueron hallados en un ensamble de 6 roedores. Cinco nuevos hospedadores y 12 nuevos registros geográficos son reportados para la región del Chaco Húmedo. El mayor valor de prevalencia corresponde a Stilestrongylus stilesi, Hassalstrongylus mazzai, H. argentinus y Mazzanema fortuita, y los mayores valores de abundancia media e intensidad media corresponde a S. stilesi de Necromys lasiurus. Los Nippostrongylinae fue el grupo dominante en todas las especies de roedores. Se presentan los descriptores ecológicos de la comunidad componente (riqueza, número total de especímenes parásitos, índice de diversidad, equitatibilidad y dominancia). El valor más elevado del índice de riqueza fue observado para N. lasiurus (S = 6). El índice de diversidad alcanzó valores entre 1.11 en Holochilus chacarius y 0.16 in Akodon azarae. El índice de equitatibilidad presentó valores mayores para Oligoryzomys flavescens (0.96) y H. chacarius (0.81). Los valores más altos de dominancia de Berger-Parker fueron observados en A. azarae (0.96), seguido por N. lasiurus (0.86). El presente trabajo contribuye al estudio taxonómico y ecológico de las relaciones parásito-hospedador, proporcionando información sustancial a una de las ecorregiones más afectadas por las acciones antrópicas en Argentina.; The aims of this paper were to list the helminths from sympatric rodent species (Muroidea, Cricetidae) in Corrientes city, Humid Chaco ecoregion, Argentina and summarise the record and ecological data on six host species. Fourteen species of helminths were found in 6 rodent assemblages. Five new hosts and 12 new geographical reports from Humid Chaco ecoregion are provided. The higher prevalence values corresponded to Stilestrongylus stilesi, Hassalstrongylus mazzai, H. argentinus and Mazzanema fortuita, and the higher mean abundance and mean intensity values corresponded to S. stilesi from Necromys lasiurus. Nippostrongylinae was the dominant group within each host species. The ecological descriptors of component communities are given. The highest value of richness index was observed for N. lasiurus (S = 6). The diversity index reached values between the range 1.11 in Holochilus chacarius and 0.16 in Akodon azarae. The equitability index shows the highest values for Oligoryzomys flavescens (0.96) and H. chacarius (0.81). The highest value index of dominance of Berger-Parker was observed for A. azarae (0.96) followed by N. lasiurus (0.86). This study contributes to the taxonomic and ecological of the parasite-host relationships, providing substantial information to one of the ecoregions most affected by anthropic actions in Argentina.
Cobalt Corroles as Electrocatalysts for Water Oxidation: Strong Effect of Substituents on Catalytic Activity
Cobalt Corroles as Electrocatalysts for Water Oxidation: Strong Effect of Substituents on Catalytic Activity
Neuman, Nicolás Ignacio; Albold, Uta; Ferretti, Eleonora; Chandra, Shubhadeep; Steinhauer, Simon; Röner, Paul; Meyer, Franc; Doctorovich, Fabio; Vaillard, Santiago Eduardo; Sarkar, Biprajit
Two Co(III) complexes (1Py2 and 2Py2) of new corrole ligands H3L1 (5,15-bis(p-methylcarboxyphenyl)-10-(o-methylcarboxyphenyl)corrole) and H3L2 (5,15-bis(p-nitrophenyl)-10-(o-methylcarboxyphenyl)corrole) with two apical pyridine ligands have been synthesized and thoroughly characterized by cyclic voltammetry, UV-vis-NIR, and EPR spectroscopy, spectroelectrochemistry, single-crystal X-ray diffraction studies, and DFT methods. Complexes 1Py2 and 2Py2 possess much lower oxidation potentials than cobalt(III)-tris-pentafluorophenylcorrole (Co(tpfc)) and similar corroles containing pentafluorophenyl (C6F5) substituents, thus allowing access to high oxidation states of the former metallocorroles using mild chemical oxidants. The spectroscopic (UV-vis-NIR and EPR) and electronic properties of several oxidation states of these complexes have been determined by a combination of the mentioned methods. Complexes 1Py2 and 2Py2 undergo three oxidations within 1.3 V vs FcH+/FcH in MeCN, and we show that both complexes catalyze water oxidation in an MeCN/H2O mixture upon the third oxidation, with kobs (TOF) values of 1.86 s-1 at 1.29 V (1Py2) and 1.67 s-1 at 1.37 V (2Py2). These values are five times higher than previously reported TOF values for C6F5-substituted cobalt(III) corroles, a finding we ascribe to the additional charge in the corrole macrocycle due to the increased oxidation state. This work opens up new possibilities in the study of metallocorrole water oxidation catalysts, particularly by allowing spectroscopic probing of high-oxidation states and showing strong substituent-effects on catalytic activity of the corrole complexes.
Biotransformation of cladribine by a nanostabilized extremophilic biocatalyst
Biotransformation of cladribine by a nanostabilized extremophilic biocatalyst
Rivero, Cintia Wanda; de Benedetti, Eliana Celeste; Sambeth, Jorge Enrique; Trelles, Jorge Abel
Cladribine (2-chloro-2′-deoxy-β-D-adenosine) is a 2′-deoxyadenosine analogue, approved by the FDA for the treatment of hairy cell leukemia and more recently has been proved for therapeutic against many autoimmune diseases as multiple sclerosis. The biosynthesis of this compound using Thermomonospora alba CECT 3324 as biocatalyst is herein reported. This thermophilic microorganism was successfully entrapped in polyacrylamide gel supplemented with nanoclays such as bentonite. The immobilized biocatalyst (T. alba-Ac-Bent 1.00 %), was able to biosynthesize cladribine with a conversion of 89 % in 1 h of reaction and retains its activity for more than 270 reuses without significantly activity loss, showing better operational stability and mechanical properties than the natural matrix. A microscale assay using the developed system, could allow the production of at least 181 mg of cladribine in successive bioprocesses.
Análisis de la huella de carbono en bloques resuelto con polipropileno post-consumo
Análisis de la huella de carbono en bloques resuelto con polipropileno post-consumo; Analysis of the carbon footprint in blocks solved with post-consumer polypro-pylene
Saez, Vanesa Celina; Garzon, Beatriz Silvia
El cambio climático producido por el calentamiento global, es una de las problemáticas ambientales del siglo XXI a nivel global y local. Las emisiones de Gases Efecto Invernadero (GEI) de origen antropogénico, contribuyen al cambio climático de una manera determinante. En este trabajo se analiza la huella de carbono del prototipo en estudio: Bloque para cerramientos verticales no portantes, resuelto con plástico polipropileno post-consumo, en las etapas que abarca su preparación hasta su fabricación. El objetivo es determinar la cantidad dióxido de carbono equivalente, que emiten al ambiente la fabricación del producto diseñado. La metodología utilizada es la propuesta por la Norma IRAM-ISO 14040 y Norma IRAM-ISO 14044, Análisis de ciclo de Vida. Los resultados obtenidos en el cálculo de la huella de carbono, son muy alentadores. Lo que permite valorar la incorporación de residuos sólidos plásticos a la fabricación de elementos constructivos, favoreciendo la reducción de energía en sus distintas etapas del ciclo de vida y por consiguiente la reducción de las emisiones de los distintos gases de efecto invernadero.; Climate change produced by global warming is one of the environmental problems of the 21st century at a global and local level. Greenhouse Gas (GHG) emissions of anthropogenic origin contribute to climate change in a decisive way. In this work, the carbon footprint of the prototype under study is analyzed: Block for non-bearing vertical enclosures, solved with post-consumer polypropylene plastic, in the stages that include its preparation until its manufacture. The objective is to determine the equivalent amount of carbon dioxide that is emitted into the environment by the manufacture of the designed product. The methodology used is that proposed by the IRAM- ISO 14040 Standard and the IRAM-ISO 14044 Standard, Life Cycle Analysis. The results obtained in the calculation of the carbon footprint are very encouraging. This makes it possible to assess the incorporation of solid plastic waste in the manufacture of construction elements, favoring the reduction of energy in its different stages of the life cycle and consequently the reduction of emissions of the different greenhouse gases.
Epigenetic regulation of steroidogenic enzymes expressed in peripheral blood mononuclear cells from healthy individuals and from patients with chronic lymphocytic leukemia
Epigenetic regulation of steroidogenic enzymes expressed in peripheral blood mononuclear cells from healthy individuals and from patients with chronic lymphocytic leukemia
Gaydou, Luisa; Rossetti, María Florencia; Tschopp, María Virginia; Stoker, Cora; Bosquiazzo, Veronica Lis; Ramos, Jorge Guillermo
Sex hormone synthesis occurs in various organs and tissues besides the gonads, such as adrenal glands, brain, intestines, skin, fat, bone, and cells of the immune system. Regarding the latter, it is still not clear which pathways are active, and if they are modified in case of illness of the immune system. Our goal in this study was to determine mRNA expression of different steroidogenic enzymes in peripheral blood mononuclear cells (PBMCs) from healthy individuals of both sexes and of different ages, and then to compare their expression between healthy individuals and patients with Chronic Lymphocytic Leukemia (CLL). Furthermore, to elucidate possible mechanisms that regulate enzyme expression, we analyzed epigenetic events like promoter methylation. We determined that normal cells of the immune system, regardless of sex and age, expressed P450 side chain cleavage (P450scc), cytochrome P450 17α-hydroxylase/c17,20-lyase (P45017α), 3β-hydroxysteroid dehydrogenase/Δ5-Δ4-isomerase (3β-HSD), steroid 5 α reductase (5α-R) types 1, 2 and 3, 3α-hydroxysteroid dehydrogenase (3α-HSD) type 3, and 17β-hydroxysteroid dehydrogenase (17β-HSD) types 1, 3 and 5. We also established that 5α-R 1, 5α-R 3, 3α-HSD 3, 17β-HSD 1 and 17β-HSD 5 expression was altered in CLL patients, and that promoter regions of 5α-R 1, 17β-HSD 1 and 17β-HSD 5 were diferentially methylated. These results suggest that steroidogenic pathways may be affected in CLL cells, and this could be related to disease pathogenesis.
Páginas
