Metasuperficies en el diseño de antenas: una introducción

En los últimos años las metasuperficies se han perfilado como nuevos materiales que pueden utilizarse de manera eficiente en diversos campos prácticos. Aplicaciones como cambio de polarización, antenas, superficies de impedancia y cámaras anecoicas han mostrado resultados esperanzadores en diferentes líneas de investigación. Sin embargo, su modelado y caracterización es complejo comparado con otros tipos de materiales, lo que dificulta la obtención de resultados relevantes de manera eficaz. En este trabajo se presentan algunos de los resultados más importantes asociados a la física de las metasuperficies junto con sus potenciales usos y aplicaciones, describiendo su caracterización en el diseño de antenas: metapantallas y metafilms. Además, se hace un paralelo entre sus ventajas y desventajas y al final se muestran resultados de simulación de diversos subtipos de antenas y el análisis de su comportamiento a distintas frecuencias de operación

Metasuperficies en el diseño de antenas: una introducción

In recent years metasurfaces have emerged as new materials that can be efficiently used in various practical fields. Applications such as polarization change, antennas, impedance surfaces, and anechoic chambers have shown encouraging results in different lines of research. However, their modeling and characterization are complex compared to other materials, making it difficult to obtain relevant results efficiently. In this work, we present some of the most important results associated with the physics of metasurfaces, together with their potential uses and applications describing their characterization in the design of antennas: metascreens and metafilms. In addition, a parallel is made between their advantages and disadvantages, and at the end, simulation results of several antenna subtypes and the analysis of their behavior at different operating frequencies are shown.En los últimos años las metasuperficies se han perfilado como nuevos materiales que pueden utilizarse de manera eficiente en diversos campos prácticos. Aplicaciones como cambio de polarización, antenas, superficies de impedancia y cámaras anecoicas han mostrado resultados esperanzadores en diferentes líneas de investigación. Sin embargo, su modelado y caracterización es complejo comparado con otros tipos de materiales, lo que dificulta la obtención de resultados relevantes de manera eficaz. En este trabajo se presentan algunos de los resultados más importantes asociados a la física de las metasuperficies junto con sus potenciales usos y aplicaciones, describiendo su caracterización en el diseño de antenas: metapantallas y metafilms. Además, se hace un paralelo entre sus ventajas y desventajas y al final se muestran resultados de simulación de diversos subtipos de antenas y el análisis de su comportamiento a distintas frecuencias de operación

Regulation of GIP and GLP1 Receptor Cell Surface Expression by N-Glycosylation and Receptor Heteromerization

In response to a meal, Glucose-dependent Insulinotropic Polypeptide (GIP) and Glucagon-like Peptide-1 (GLP-1) are released from gut endocrine cells into the circulation and interact with their cognate G-protein coupled receptors (GPCRs). Receptor activation results in tissue-selective pleiotropic responses that include augmentation of glucose-induced insulin secretion from pancreatic beta cells. N-glycosylation and receptor oligomerization are co-translational processes that are thought to regulate the exit of functional GPCRs from the ER and their maintenance at the plasma membrane. Despite the importance of these regulatory processes, their impact on functional expression of GIP and GLP-1 receptors has not been well studied. Like many family B GPCRs, both the GIP and GLP-1 receptors possess a large extracellular N-terminus with multiple consensus sites for Asn-linked (N)-glycosylation. Here, we show that each of these Asn residues is glycosylated when either human receptor is expressed in Chinese hamster ovary cells. N-glycosylation enhances cell surface expression and function in parallel but exerts stronger control over the GIP receptor than the GLP-1 receptor. N-glycosylation mainly lengthens receptor half-life by reducing degradation in the endoplasmic reticulum. N-glycosylation is also required for expression of the GIP receptor at the plasma membrane and efficient GIP potentiation of glucose-induced insulin secretion from the INS-1 pancreatic beta cell line. Functional expression of a GIP receptor mutant lacking N-glycosylation is rescued by co-expressed wild type GLP1 receptor, which, together with data obtained using Bioluminescence Resonance Energy Transfer, suggests formation of a GIP-GLP1 receptor heteromer

Salmonella identified in pigs in Kenya and Malawi reveals the potential for zoonotic transmission in emerging pork markets

Salmonella is a major cause of foodborne disease globally. Pigs can carry and shed non-typhoidal Salmonella (NTS) asymptomatically, representing a significant reservoir for these pathogens. To investigate Salmonella carriage by African domestic pigs, faecal and mesenteric lymph node samples were taken at slaughter in Nairobi, Busia (Kenya) and Chikwawa (Malawi) between October 2016 and May 2017. Selective culture, antisera testing and whole genome sequencing were performed on samples from 647 pigs; the prevalence of NTS carriage was 12.7% in Busia, 9.1% in Nairobi and 24.6% in Chikwawa. Two isolates of S. Typhimurium ST313 were isolated, but were more closely related to ST313 isolates associated with gastroenteritis in the UK than bloodstream infection in Africa. The discovery of porcine NTS carriage in Kenya and Malawi reveals potential for zoonotic transmission of diarrhoeal strains to humans in these countries, but not for transmission of clades specifically associated with invasive NTS disease in Africa

Diet and food strategies in a southern al-Andalusian urban environment during Caliphal period, ecija, Sevilla

The Iberian medieval period is unique in European history due to the widespread socio-cultural changes that took place after the arrival of Arabs, Berbers and Islam in 711 AD. Recently, isotopic research has been insightful on dietary shifts, status, resource availability and the impact of environment. However, there is no published isotopic research exploring these factors in southern Iberian populations, and as the history of this area differs to the northern regions, this leaves a significant lacuna in our knowledge. This research fills this gap via isotopic analysis of human (n = 66) and faunal (n = 13) samples from the 9th to the 13th century Écija, a town renowned for high temperatures and salinity. Stable carbon (δ13C) and nitrogen (δ15N) isotopes were assessed from rib collagen, while carbon (δ13C) values were derived from enamel apatite. Human diet is consistent with C3 plant consumption with a very minor contribution of C4 plants, an interesting feature considering the suitability of Écija to C4 cereal production. δ15N values vary among adults, which may suggest variable animal protein consumption or isotopic variation within animal species due to differences in foddering. Consideration of δ13C collagen and apatite values together may indicate sugarcane consumption, while moderate δ15N values do not suggest a strong aridity or salinity effect. Comparison with other Iberian groups shows similarities relating to time and location rather than by religion, although more multi-isotopic studies combined with zooarchaeology and botany may reveal subtle differences unobservable in carbon and nitrogen collagen studies alone.OLC is funded by Plan Galego I2C mod.B (ED481D 2017/014). The research was partially funded by the projects “Galician Paleodiet” and by Consiliencia network (ED 431D2017/08) Xunta de GaliciaS

Nanotransfection-based vasculogenic cell reprogramming drives functional recovery in a mouse model of ischemic stroke

Ischemic stroke causes vascular and neuronal tissue deficiencies that could lead to substantial functional impairment and/or death. Although progenitor-based vasculogenic cell therapies have shown promise as a potential rescue strategy following ischemic stroke, current approaches face major hurdles. Here, we used fibroblasts nanotransfected with Etv2, Foxc2, and Fli1 (EFF) to drive reprogramming-based vasculogenesis, intracranially, as a potential therapy for ischemic stroke. Perfusion analyses suggest that intracranial delivery of EFF-nanotransfected fibroblasts led to a dose-dependent increase in perfusion 14 days after injection. MRI and behavioral tests revealed ~70% infarct resolution and up to ~90% motor recovery for mice treated with EFF-nanotransfected fibroblasts. Immunohistological analysis confirmed increases in vascularity and neuronal cellularity, as well as reduced glial scar formation in response to treatment with EFF-nanotransfected fibroblasts. Together, our results suggest that vasculogenic cell therapies based on nanotransfection-driven (i.e., nonviral) cellular reprogramming represent a promising strategy for the treatment of ischemic stroke

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery