Fossil plants from the Lower Cretaceous (upper Aptian) of the La Cantera Formation, Argentina, are described. The fossils studied represent a leafy shooting system with several orders of articulated and striated axes and attached leaves with unequivocal ephedroid affinity. We also found associated remains of ovulate cones with four whorls of sterile bracts, which contain two female reproductive units (FRU). Ovulate cone characters fit well within the genus Ephedra. Special characters in the ovulate cones including an outer seed envelope with two types of trichomes, allowed us to consider our remains as a new Ephedra species. Abundant dispersed ephedroid pollen obtained from the macrofossil-bearing strata also confirms the abundance of Ephedraceae in the basin. The co-occurrence of abundant fossil of Ephedra (adapted to dry habitats) associated with thermophilic cheirolepideacean conifer pollen (Classopollis) in the unit would suggest marked seasonality at the locality during the Early Cretaceous. Furthermore, the floristic association is linked to dry sensitive rocks in the entire section. The macro- and microflora from San Luis Basin are similar in composition to several Early Cretaceous floras from the Northern Gondwana floristic province, but it may represent one of the southernmost records of an arid biome in South America.
The antibacterial activity against Staphylococcus aureus of aerogels fabricated from colloidal suspensions of chitosan/chondroitin sulfate nanocomplexes is analyzed. Upon freeze-drying the colloidal suspensions, the aerogels presented a porous structure made of microsheets and microfibers. The aerogels could, in addition, be loaded with antimicrobial agents. Loaded with the antibiotic erythromycin, the aerogels showed crystalline deposits, affecting the topography of the samples as well as their mechanical properties, showing a decrease on the apparent Young’s modulus and hardness at 40% deformation. Loaded with elephant garlic (Allium ampeloprasum L. var. ampeloprasum) extract, the aerogels showed texturization of the microsheets and microfibers, and the higher relative mass allowed an increase on the apparent Young’s modulus and hardness at 40% deformation with respect to pristine aerogels. Unloaded aerogels showed activity against Staphylococcus aureus, including a methicillin-resistant strain. The release of erythromycin from the aerogels to an agar environment is governed by equilibrium forces with the polysaccharides, which allow modulating the load of antibiotic and its concomitant diffusion from the material. The diffusion of the active components of the elephant garlic extract did not show a dependence on the polysaccharide content, revealing a week interaction. The elephant garlic extract resulted active against the methicillin-resistant Staphylococcus aureus strain, while resistance was found for the antibiotic, revealing the therapeutic potential of the natural extract. The antimicrobial aerogels may be used for several therapeutic purposes, such as healing of infected chronic wounds.
RESUMENLa acrofobia es un miedo irracional, exagerado e irreprimible a las alturas, las personas que la padecen pueden llegar a sentir temor no solamente desde grandes alturas, sino también al estar en un balcón, unas escaleras, entre otras. En la actualidad existen diferentes tipos de tratamientos como lo son los psicológicos, los de exposición, los cognitivoscomportamentales, donde se ha considerado la exposición como la manera más efectiva de afrontar estar fobia, sin embargo, la realidad virtual se ha venido convirtiendo en una de las técnicas más utilizadas e innovadoras porque ofrece entornos virtuales donde se cuenta con la ventaja de poder controlar y personalizar el ambiente dependiendo de la necesidad del paciente, por tanto promete ser una buena manera de llevar a cabo la terapia de exposición, ya que permite proporcionar sensaciones y la idea general de estar presente en una situación temida donde la persona no se encontrará en ningún momento en peligro físico y podrá interactuar con los elementos del ambiente a través de diferentes herramientas que contribuyen a que la realidad virtual sea todo un éxito. P P P P Palabras clave: alabras clave: alabras clave: alabras clave: alabras clave: miedo a las alturas, realidad virtual, exposición virtual, plataforma. ABSTRACTAcrophobia is an irrational fear, exaggerated and irrepressible to the heights, people who suffer from it can become afraid not only from great heights, but also from being on a balcony, stairs, among others. Nowadays there are different types of treatments such as psychological, exposure, cognitive-behavioral, where exposure has been considered as the most effective way to face this phobia, however, virtual reality has been becoming one of the most used and innovative techniques, because it offers virtual environments where advantage such as been able to control and customize the environment depending on the need of the patient. Therefore promises to be a good way to carry out the exposure therapy, since it allows you to provide sensations and the general idea of being present in a dreaded situation where the person will not be at any time in physical danger and will be able to interact with the elements of diferent environments through different tools that contribute that virtual reality is a success. probable las cuales han demostrado ser eficaces, pero dada la naturaleza de estos trastornos o miedos suelen ser costosas en términos de tiempo, dinero y esfuerzos, por último se encontró la realidad virtual la cual actualmente constituye una de las tecnologías más emergentes que permite generar ambientes tridimensionales, simulando la realidad, es por ello que se ha convertido en los últimos años en una herramienta de trabajo muy útil para las ciencias de la salud, tanto en la investigación básica como en la aplicada, una de las áreas donde ha tenido gran impacto han sido las psicológicas ya que ha empezado a ser una de las técnicas más utilizadas y novedosas en el tratamiento de trastornos psicológicos como lo son las fobias.En este ámbit...
The Triassic paleofloras of Argentina are mainly known for their vegetative elements. During the last decade, several contributions have focused on the study of Triassic reproductive structures. Here, we provide new information on reproductive structures recovered from two Triassic units from the central-west of Argentina: the Agua de la Zorra Formation (Cuyana Basin) and the Los Rastros Formation (Ischigualasto-Villa Unión Basin). These specimens had been described in previous contributions, however, the taxonomic assignment of the materials remained undetermined. In this work, a redescription of the materials is provided, allowing the taxonomic assignment of the specimens. The Agua de la Zorra Formation female reproductive structures were assigned to Matatiella sp. (Matatiellaceae) and to Rissikiostrobus reductus (Podocarpaceae). The female strobilus specimen registered in the Los Rastros Formation was assigned to the genus Umkomasia (Umkomasiaceae). This contribution represents a step forward to a better understanding of the reproductive structures for the Triassic of Gondwana. Keywords: Matatiella, Rissikiostrobus, Umkomasia, Gondwana, Argentina.
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