259 research outputs found
Sobre los materiales tipo de los géneros Interatherium Ameghino, 1887 e Icochilus Ameghino, 1889 (Interatheriidae, Notoungulata, Mammalia) del Mioceno temprano de la provincia de Santa Cruz, Argentina
Los primeros Interatheriinae (Interatheriidae, Notoungulata) en conocerse fueron eregidos por Florentino Ameghino a partir de fósiles colectados por su hermano Carlos en diversos afloramientos argentinos del Mioceno temprano en la provincia de Santa Cruz, los cuales están depositados en diferentes instituciones nacionales. Con el objetivo de realizar un estudio sistemático de la subfamilia, es esencial revisar la mayor cantidad de ejemplares posible, iniciando con los ejemplares tipo de las especies bajo estudio. Debido a que Florentino Ameghino nunca referenció formalmente los tipos con un número de colección, su identificación se torna una tarea compleja. En consecuencia, al estudiar las especies fundadas por Ameghino dentro de los géneros Interatherium e Icochilus, identificamos una falta de correspondencia entre ciertos ejemplares que aparecían catalogados como tipos y las descripciones originales. En esta contribución, presentamos los ejemplares tipo de 18 de las 21 especies santacrucenses de Interatherium (4) e Icochilus (14), alojados en la colección paleontológica del Museo de la Plata y la Colección Nacional Ameghino en el Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. Se presentan cuatro casos de estudio: a) especímenes correctamente tipificados; b) ejemplares erróneamente tipificados; c) especímenes definidos como tipo en el catálogo, cuyo estado no puede ser evaluado porque están extraviados; y d) ejemplares no catalogados como tipos que aquí se reconocen como tales. Debido a que la selección de la especie tipo de Icochilus estaba pendiente, Ic. extensus se designa como tal. Los lectotipos de Ic. extensus e Ic. multidentatus son seleccionados a partir de los respectivos sintipos identificados.The first known Interatheriinae (Interatheriidae, Notoungulata) were described by Florentino Ameghino based on fossils collected by his brother Carlos in diverse Argentinean early Miocene outcrops in the Santa Cruz Province, which are housed at different institutions. In order to perform a systematic study of the subfamily, it is essential to revise as much specimens as possible, but first of all the type material of the species under study. Due to the fact that Florentino Ameghino never referred to any type specimens with a collection number in any of his publications, their identification becomes a complex task. In consequence, when studying the species erected by Ameghino within the genera Interatherium and Icochilus, we identified a lack of correspondence between some materials catalogued as type specimens and the original descriptions. In this contribution, we present the type specimens of 18 out of the 21 Santacrucian species of Interatherium (4) and Icochilus (14) within the paleontological collection of the Museo de La Plata and Ameghino National Collection at the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Four case studies are presented: a) specimens correctly identified; b) materials erroneously catalogued as type specimens; c) specimens catalogued as type, whose status cannot be evaluated because they are lost; and d) specimens not catalogued as types, but herein recognised as such. As the selection of the type species of Icochilus was pending, Ic. extensus is herein designated as such. The lectotypes of Ic. extensus and Ic. multidentatus are selected among their identified syntypes.Fil: Fernández, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; ArgentinaFil: Fernicola, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; ArgentinaFil: Cerdeño Serrano, Maria Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin
Activity of cefiderocol against high-risk clones of multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa and Stenotrophomonas maltophilia
BACKGROUND:
Cefiderocol is a novel siderophore cephalosporin, developed for activity against MDR Gram-negative bacilli (MDR-GNB).
OBJECTIVES:
To assess the in vitro antibacterial activity of cefiderocol against a collection of MDR-GNB clinical isolates from hospitals in southern Spain.
METHODS:
Two hundred and thirty-one isolates of successful clones were tested: 125 Enterobacterales (121 ESBL- and/or carbapenemase-producing Klebsiella pneumoniae and 4 carbapenemase-producing Enterobacter cloacae), 80 Acinetobacter baumannii, 6 Pseudomonas aeruginosa and 20 Stenotrophomonas maltophilia. Ceftolozane/tazobactam, ceftazidime, ceftazidime/avibactam, cefepime, aztreonam, meropenem, amikacin, ciprofloxacin, colistin and tigecycline were used as comparators against Enterobacterales, P. aeruginosa and A. baumannii. Minocycline, levofloxacin and trimethoprim/sulfamethoxazole were studied against S. maltophilia instead of aztreonam, ciprofloxacin and cefepime. MICs were determined by broth microdilution according to CLSI guidelines. MIC determination was performed in CAMHB for all antimicrobials except cefiderocol, where iron-depleted CAMHB was used.
RESULTS:
Cefiderocol showed potent in vitro activity against the isolates analysed. MIC50 and MIC90 values were in the ranges 0.125-8 mg/L and 0.5-8 mg/L, respectively, and 98% of isolates were inhibited at ≤4 mg/L. Only five isolates showed cefiderocol MICs of >4 mg/L: three ST2/OXA-24/40-producing A. baumannii, one ST114/VIM-1-producing E. cloacae and one ST114/VIM-1 + OXA-48-producing E. cloacae. All KPC-3-producing K. pneumoniae were susceptible to cefiderocol, even those resistant to ceftazidime/avibactam. P. aeruginosa isolates showed cefiderocol MICs of <4 mg/L, including those resistant to ceftolozane/tazobactam. S. maltophilia isolates displayed cefiderocol MICs of <4 mg/L, including those resistant to levofloxacin and/or trimethoprim/sulfamethoxazole.
CONCLUSIONS:
Cefiderocol showed excellent activity against MDR-GNB, including carbapenem-resistant isolates, and was the most active antimicrobial tested against this collection
Synthesis and Characterization of Environmentally Friendly Chitosan–Arabic Gum Nanoparticles for Encapsulation of Oregano Essential Oil in Pickering Emulsion
The encapsulation of bioactive agents through the utilization of biodegradable nanoparticles
is a topic of considerable scientific interest. In this study, microcapsules composed of chitosan (CS)
and Arabic gum (GA) nanoparticles were synthesized, encapsulating oregano essential oil (OEO)
through Pickering emulsions and subsequent spray drying. The optimization of hybrid chitosan and
Arabic gum (CS–GA) nanoparticle formation was carried out via complex coacervation, followed
by an assessment of their behavior during the formation of the emulsion. Measurements of the
size, contact angle, and interfacial tension of the formed complexes were conducted to facilitate the
development of Pickering emulsions for encapsulating the oil under the most favorable conditions.
The chitosan–Arabic gum capsules were physically characterized using scanning electron microscopy
and fitted to the Beerkan estimation of soil transfer (BEST) model to determine their size distribution.
Finally, the OEO encapsulation efficiency was also determined. The optimum scenario was achieved
with the CS–GA 1–2 capsules at a concentration of 2% wt, featuring a contact angle of 89.1 degrees,
which is ideal for the formation of oil/water (O/W) emulsions. Capsules of approximately 2.5 m
were obtained, accompanied by an encapsulation efficiency of approximately 60%. In addition, the
hybrid nanoparticles that were obtained showed high biodegradability. The data within our study
will contribute fundamental insights into CS–GA nanoparticles, and the quantitatively analyzed
outcomes presented in this study will hold utility for forthcoming applications in environmentallySpanish Ministry of Science, grant number FPU17-0335
Is Data Protection-friendly Artificial Intelligence Possible?
La Inteligencia artificial es un reto clave en la cuarta revolución industrial que vivimos. El artículo pretende analizar la compatibilidad de ésta con el derecho a la protección de datos. Para ello se analizan los principios que subyacen a la regulación y se estudia el encaje de las características de la tecnología en los mismos. Se destacan los principales derechos de los sujetos, así como las obligaciones de los responsables de los tratamientos. Especial atención se presta a la discriminación algorítmica en el caso de los perfiles y el marketing político, que supone un reto a evitar por su vulneración del principio de igualdad y justicia en el tratamiento de la información personal. Resulta esencial salvaguardar el derecho a la explicabilidad algorítmica. Se concluye con un análisis de la necesaria regulación que está en fase de discusión en Europa.Artificial Intelligence is a key challenge in the fourth industrial revolution we are living. The article aims to analyze its compatibility with the right to data protection. the principles underlying the regulation are analyzed and the fit of the characteristics of the technology with these principles is studied. The main rights of the subjects are highlighted, as well as the obligations of data controllers. Special attention is paid to algorithmic discrimination in the context of profiles and political marketing, which is a challenge to be avoided due to its violation of the principle of equality and fairness in the processing of personal information. It is essential to safeguard the right to algorithmic explainability. It concludes with an analysis of the necessary regulation currently under discussion in Europe
Identification of type materials of the species of Protypotherium Ameghino, 1885 and Patriarchus Ameghino, 1889 (Notoungulata: Interatheriidae) erected by Florentino Ameghino
The first collections of Interatheriinae (Interatheriidae, Notoungulata) were created by the brothers Florentino and Carlos Ameghino, based on fossil specimens collected from diverse outcrops of Argentina and housed at different national institutions. In order to perform a systematic study of the subfamily, it is essential to revise as much specimens as possible, but first of all those that were used to establish the respective species, that is, the type material. Florentino Ameghino never referred to the collection number of the type specimens of the species he erected in any of his publications; this fact added to the occasional absence of illustrations and adequate descriptions, all of which make their identification a complex task. Thus, when studying the species erected by Florentino Ameghino within Protypotherium and Patriarchus, we recognised a lack of correspondence between some specimens that appeared labelled as types in the collections and the original descriptions of these species. In this contribution, we identify the type specimens of the eleven species of Protypotherium and eight of Patriarchus founded by Florentino Ameghino, housed in the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (Buenos Aires, Argentina) and the Zoological Museum of the University of Copenhagen (Denmark). Three case studies are presented: a) specimens correctly identified; b) specimens erroneously catalogued as type material; and c) specimens not established as types in Ameghino's catalogue, but herein recognised as such. Lectotype and paralectotype of P. antiquum are herein designated.Fil: Fernández, Mercedes. Universidad Nacional de Luján. Departamento de Ciencias Básicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Fernicola, Juan Carlos. Universidad Nacional de Luján. Departamento de Ciencias Básicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Cerdeño Serrano, Maria Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Reguero, Marcelo Alfredo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Influence of ozonation processes on the microbial degradation of surfactants
The influence of ozonation of aqueous solutions of non-ionic surfactants was investigated in this study. The research
was conducted using solutions of amine oxide based surfactants. These surfactants constitute a particular class of
non-ionic surfactants that exhibit cationic behaviour in acid solution, they show good foaming properties and are skin
compatible. The ozonation process was carried out at 25ºC in a stirred tank reactor for 30 min, where gaseous ozone
was bubbled. The degree of mineralization achieved after the ozonation process was evaluated by measuring the total
organic carbon before and after ozonation. The influence of ozonation on biodegradability of the solutions was
studied using the biodegradation test by Pseudomonas putida. Biodegradation efficiency of the ozonated amine
oxides based surfactants was also evaluated. It was found that the effectiveness of ozonation depended on the
chemical structure of surfactant molecule. Ozonation only slightly improved biodegradation of these surfactants
Silica micro-and nanoparticles reduce the toxicity of surfactant solutions
In this work, the toxicity of hydrophilic fumed silica microand
nanoparticles of various sizes (7 nm, 12 nm, and 50 μm) was evaluated
using the luminescent bacteria Vibrio fischeri. In addition, the toxicity
of an anionic surfactant solution (ether carboxylic acid), a nonionic
surfactant solution (alkyl polyglucoside), and a binary (1:1) mixture of
these solutions all containing these silica particles was evaluated.
Furthermore, this work discusses the adsorption of surfactants onto
particle surfaces and evaluates the effects of silica particles on the
surface tension and critical micellar concentration (CMC) of these
anionic and nonionic surfactants. It was determined that silica particles
can be considered as non-toxic and that silica particles reduce the
toxicity of surfactant solutions. Nevertheless, the toxicity reduction
depends on the ionic character of the surfactants. Differences can be
explained by the different adsorption behavior of surfactants onto the
particle surface, which is weaker for nonionic surfactants than for
anionic surfactants. Regarding the effects on surface tension, it was
found that silica particles increased the surface activity of anionic
surfactants and considerably reduced their CMC, whereas in the case of
nonionic surfactants, the effects were reversed
Antagonistic Toxic Effects of Surfactants Mixtures to Bacteria Pseudomonas putida and Marine Microalgae Phaeodactylum tricornutum
Surfactants can be found in an ever-widening variety of products and applications, in
which the combination of several types of surfactants is used to reinforce their properties, looking for
synergistic effects between them. After use, they tend to be discarded into wastewater, ending up in
aquatic bodies with concerning harmful and toxic effects. The aim of this study is the toxicological
assessment of three anionic surfactants (ether carboxylic derivative, EC) and three amphoteric
surfactants (amine-oxide-based, AO), individually and in binary mixtures of them (1:1 w/w), to
bacteria Pseudomonas putida and marine microalgae Phaeodactylum tricornutum. Critical Micelle
Concentration (CMC) was determined to demonstrate the capacity to reduce surface tension and the
toxicity of the surfactants and mixtures. Zeta potential (ζ-potential) and micelle diameter (MD) were
also determined to confirm the formation of mixed surfactant micelles. The Model of Toxic Units
(MTUs) was used to quantify the interactions of surfactants in binary mixtures and to predict if the
concentration addition or response addition principle can be assumed for each mixture. The results
showed a higher sensitivity of microalgae P. tricornutum to the surfactants tested and their mixtures
than bacteria P. putida. Antagonism toxic effects have been detected in the mixture of EC + AO and in
one binary mixture of different AOs; this is to say, the mixtures showed lower toxicity than expected.Ministry of Universities of the Spanish Government within the predoctoral grant FPU (Ayudas para la Formacion de Profesorado Universitario)
FPU17/0335
Dihydroxyacetone crystallization: Process, environmental, health and safety criteria application for solvent selection
Dihydroxyacetone is a good candidate to valorize the excess glycerol obtained as byproduct in biodiesel production. Crystallization is likely the key unit operation to obtain a high quality and pure dihydroxyacetone. The selection of an appropriate solvent for crystallization is not trivial and depends on multiple factors. At the present work a new solvent selection methodology, based on solvents relative comparisons, is described and applied to dihydroxyacetone crystallization as a case study. The procedure accounts not only for process factors such as solubility and yield, but also for cost, recycling, disposal, environmental, health and safety issues. Solubility and theoretical yield data for dihydroxyacetone in methanol, ethanol and 2-propanol were experimentally determined, while cost, life-cycle assessment, environmental, health and safety data of solvents were gathered from different bibliographic sources, software and databases. Among the solvents assessed, methanol resulted as the best overall choice for DHA crystallization. The methodology proved to be a suitable, simple and flexible procedure for solvent selection at the initial stages of the crystallization operation design, being able to be upgraded for advanced stages of the crystallization process development.Grupos de Investigación RNM332 y TEP21
- …