Polymeric Particulates to Improve Oral Bioavailability of Peptide Drugs

Oral administration remains the most convenient way of delivering drugs. Recent advances in biotechnology have produced highly potent new molecules such as peptides, proteins and nucleic acids. Due to their sensitivity to chemical and enzymatic hydrolysis as well as a poor cellular uptake, their oral bioavailability remains very low. Despite sophisticated new delivery systems, the development of a satisfactory oral formulation remains a challenge. Among the possible strategies to improve the absorption of drugs, micro- and nanoparticles represent an exciting approach to enhance the uptake and transport of orally administered molecules. Increasing attention has been paid to their potential use as carriers for peptide drugs for oral administration. This article reviews the most common manufacturing methods for polymeric particles and the physiology of particle absorption from the gastrointestinal (GI) tract. In a second part, the use of polymeric particulate systems to improve the oral absorption of insulin is discussed

Habitat, world geographic range, and embryonic development of hosts explain the prevalence of avian hematozoa at small spatial and phylogenetic scales

The factors explaining interspecific differences in prevalences of blood parasites in birds are poorly known. We simultaneously assessed 20 social, ecological, life history, and sampling-related variables that could influence hemoparasite prevalences among diurnal birds of prey in Spain. Our results show that multiple factors are responsible for the studied host-parasite association. We confirmed for the first time that prevalence is inversely correlated to the embryonic development period, and thus probably to immune performance, even among closely related birds. Macrohabitat features related to vector availability are also important, prevalences being higher in species breeding in forested habitats. Finally, prevalence is positively correlated with the host's world geographic range. We hypothesize that larger geographic ranges offered more opportunities for host-vector-hemoparasite associations to become established. The results from our multivariate analyses differ from those obtained through univariate ones, showing that all potential factors should be assessed jointly when testing any ecological or evolutionary hypothesis dealing with parasites.Peer Reviewe

Recursos dispoñibles e modalidades de emprego das actividades manipulativas na física

É ben sabido que unha forma de facilitar o aprendizaxe dos contidos relacionados coa Física consiste no emprego de metodoloxías activas. Entre as distintas opcións, o profesorado pode empregar as Actividades Manipulativas (AMs) que utilizan, debidamente contextualizados, materiais, obxectos, instrumentos ou montaxes experimentais tanto na aula como fora dela (Costa e Dorrío 2010). Neste obradoiro eminentemente práctico e interactivo presentamos unha visión actualizada de recursos e modalidades de utilización de AMs que permitan ao profesorado interesado continuar posteriormente a propia exploración individual

Seed dispersal by macaws shapes the landscape of an Amazonian ecosystem

Seed dispersal is one of the most studied plant–animal mutualisms. It has been proposed that the dispersal of many large-seeded plants from Neotropical forests was primarily conducted by extinct megafauna, and currently by livestock. Parrots can transport large fruits using their beaks, but have been overlooked as seed dispersers. We demonstrate that three macaws (Ara ararauna, A. glaucogularis and A. severus) are the main dispersers of the large-seeded motacú palm Attalea princeps, which is the biomass-dominant tree in the Bolivian Amazonian savannas. Macaws dispersed fruits at high rates (75– 100% of fruits) to distant (up to 1200 m) perching trees, where they consumed the pulp and discarded entire seeds, contributing to forest regeneration and connectivity between distant forests islands. The spatial distribution of immature palms was positively associated to the proximity to macaws’ perching trees and negatively to the proximity to cattle paths. The disperser role of livestock, presumably a substitute for extinct megafauna, had little effect due to soil compaction, trampling and herbivory. Our results underscore the importance of macaws as legitimate, primary dispersers of large-seeded plants at long distances and, specifically, their key role in shaping the landscape structure and functioning of this Amazonian biomePeer reviewe

Quantitative determination of the antitumor alkyl ether phospholipid edelfosine by reversed-phase liquid chromatography-electrospray mass spectrometry: application to cell uptake studies and characterization of drug delivery systems.

Edelfosine is a synthetic alkyl ether phospholipid that represents a promising class of antitumor agents. However, analytical methods to measure these type compounds are scarce. The lack of a reliable methodology to quantify edelfosine is a major problem in ongoing and scheduled preclinical and clinical trials with this drug. We evaluated the applicability of high-performance liquid chromatography–mass spectrometry to determine edelfosine in biological samples and polymeric delivery systems. Sample pre-treatment involved polymer precipitation or cell lysis with methanol. HPLC separation was performed on an Alltima RPC18 narrow-bore column and edelfosine quantification was done by electrospray ionization mass spectrometry (ESI-MS) using positive ion mode and selected ion monitoring. Assays were linear in the tested range of 0.3–10 μg/ml. The limit of quantification was 0.3 ng/sample in both matrices, namely biological samples and polymeric delivery systems. The interassay precision ranging from 0.79 to 1.49%, with relative errors of −6.7 and 12.8%. Mean extraction recovery was 95.6%. HPLC–ESI-MS is a reliable system for edelfosine analysis and quantification in samples from different sources, combining advantages of full automation (rapidity, ease of use, no need of extensive extraction procedures) with high analytical performance and throughput

Teacher growth in exploiting mathematics competencies through STEAM projects

This article is aimed at educators concerned with curricular initiatives that foster STE(A)M projects in secondary education to promote mathematics competencies. Research has recently reported that these projects superficially address mathematics content, hampering the development of competencies the consensus deems necessary to prepare citizens for daily life. This study shows that learning goals may be achieved when teachers receive personalised training and sustained assistance in their project experiences. We examine how two Spanish teachers, with advisors? support, progress in exploiting mathematics competencies within the implementation of a single project each over a period of 3 years. Their evolution was not the result of minor recommendations but of continuous interactions with the advisors. These interactions intended to maintain a balance between teacher confidence and project enhancements, which required commitment and constancy. Four of the five competencies considered in the Spanish curriculum emerged powerfully after sustained refinement. The frequently mobilised competencies were intra-mathematics, representations, as well as collaborative work and positive identity, followed by modelling. The last of which was difficult to address, but when it was, the other three emerged more naturally. Computational thinking was poorly represented mainly because of the advisors? background and its recent incorporation into the reference curriculum. The teachers? progress was influenced by the advisor?s academic background, pedagogical expertise, ability to transfer research outcomes into teaching, and experience supporting others.This work is supported by the Spanish State Plan (PID2021-122326OB-I00) and the Erasmus+ Program of the European Union (2020-1-ES01-KA201-082102). The European Commission support to this publication does not constitute endorsement of the contents, reflecting only authors’ views. The Commission is not responsible for any use of the present information