Reappraising myocardial fibrosis in severe aortic stenosis: an invasive and non-invasive study in 133 patients

Aims: To investigate myocardial fibrosis (MF) in a large series of severe aortic stenosis (AS) patients using invasive biopsy and non-invasive imaging. Methods and results: One hundred thirty-three patients with severe, symptomatic AS accepted for surgical aortic valve replacement underwent cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume fraction (ECV) quantification. Intra-operative left ventricular (LV) biopsies were performed by needle or scalpel, yielding tissue with (n = 53) and without endocardium (n = 80), and compared with 10 controls. Myocardial fibrosis occurred in three patterns: (i) thickened endocardium with a fibrotic layer; (ii) microscopic scars, with a subendomyocardial predominance; and (iii) diffuse interstitial fibrosis. Collagen volume fraction (CVF) was elevated (P < 0.001) compared with controls, and higher (P < 0.001) in endocardium-containing samples with a decreasing CVF gradient from the subendocardium (P = 0.001). Late gadolinium enhancement correlated with CVF (P < 0.001) but not ECV. Both LGE and ECV correlated independently (P < 0.001) with N-terminal pro-brain natriuretic peptide and high-sensitivity-troponin T. High ECV was also associated with worse LV remodelling, left ventricular ejection fraction and functional capacity. Combining high ECV and LGE better identified patients with more adverse LV remodelling, blood biomarkers and histological parameters, and worse functional capacity than each parameter alone. Conclusion: Myocardial fibrosis in severe AS is complex, but three main patterns exist: endocardial fibrosis, microscars (mainly in the subendomyocardium), and diffuse interstitial fibrosis. Neither histological CVF nor the CMR parameters ECV and LGE capture fibrosis in its totality. A combined, multi-parametric approach with ECV and LGE allows best stratification of AS patients according to the response of the myocardial collagen matrix

Variability in sediment particle size, mineralogy, and Fe mode of occurrence across dust-source inland drainage basins:the case of the lower Drâa Valley, Morocco

The effects of desert dust upon climate and ecosystems depend strongly on its particle size and size-resolved mineralogical composition. However, there is very limited quantitative knowledge on the particle size and composition of the parent sediments along with their variability within dust-source regions, particularly in dust emission hotspots. The lower Drâa Valley, an inland drainage basin and dust hotspot region located in the Moroccan Sahara, was chosen for a comprehensive analysis of sediment particle size and mineralogy. Different sediment type samples (n=42) were collected, including paleo-sediments, paved surfaces, crusts, and dunes, and analysed for particle-size distribution (minimally and fully dispersed samples) and mineralogy. Furthermore, Fe sequential wet extraction was carried out to characterise the modes of occurrence of Fe, including Fe in Fe (oxyhydr)oxides, mainly from goethite and hematite, which are key to dust radiative effects; the poorly crystalline pool of Fe (readily exchangeable ionic Fe and Fe in nano-Fe oxides), relevant to dust impacts upon ocean biogeochemistry; and structural Fe. Results yield a conceptual model where both particle size and mineralogy are segregated by transport and deposition of sediments during runoff of water across the basin and by the precipitation of salts, which causes a sedimentary fractionation. The proportion of coarser particles enriched in quartz is higher in the highlands, while that of finer particles rich in clay, carbonates, and Fe oxides is higher in the lowland dust emission hotspots. There, when water ponds and evaporates, secondary carbonates and salts precipitate, and the clays are enriched in readily exchangeable ionic Fe, due to sorption of dissolved Fe by illite. The results differ from currently available mineralogical atlases and highlight the need for observationally constrained global high-resolution mineralogical data for mineral-speciated dust modelling. The dataset obtained represents an important resource for future evaluation of surface mineralogy retrievals from spaceborne spectroscopy.</p

Tuning Single-Molecule Conductance in Metalloporphyrin-Based Wires via Supramolecular Interactions.

Nature has developed amazing supramolecular constructs to deliver outstanding charge transport capabilities using metalloporphyrin-based supramolecular stacks.1 Here we are incorporating simple, naturally inspired supramolecular interactions via the axial complexation of metalloporphyrins into the formation of a single-molecule wire in a nanoscale gap to dissect the resulting electron pathways through the final chemical adduct. We observe that small structural changes in the axial coordinating linkers result in dramatic changes in the transport properties through the metalloporphyrin-based wire. The increased flexibility of a pyridine-4-yl-methanethiol ligand due to an extra methyl group as compared to a more rigid mercaptopyridine linker allows the former to adopt an unexpected highly conductive stacked structure between the two junction electrodes and the metalloporphyrin ring. DFT calculations reveal a molecular junction structure composed of a shifted stack of the three molecular backbones; the two pyridine ligands sandwiching the metalloporphyrin ring, which is stabilized by a combination of the porphyrin metal center coordinating the pyridinic N and the pyridine/porphyrin overlapping. Contrarily, the more rigid 4-mercaptopyridine ligand presents a more expected octahedral coordination of the metalloporphyrin metal center, leading to much lower conductance. Furthermore, we show that a mechanical forced imposed along the molecular wire axis results in a variety of more extended supramolecular structures between the pyridine linkers and the porphyrin ring spanning the tunneling gap and scoring relatively high conductance values. This works sets an example of the use of supramolecular chemistry in the construction of efficient molecular conduits towards the development of supramolecular electronics, a concept already exploited in natural organisms

Morphosedimentary characterization of the Capbreton submarine canyon system, Bay of Biscay (Cantabrian Sea)

Various studies have been carried out to the declaration of new marine protected areas for their importance for habitats, according to the Natura 2000 Network. One of these sites is a sector of the Capbreton Submarine Canyon System, located in front of the Basque Country coast, in the Bay of Biscay (North Atlantic). During the Intemares_CapBreton 0619 and 0620 surveys; bathymetric, backscatter, high-resolution parametric data and samples of sediments, rocks and benthic communities from the seabed were acquired. The study was completed by recording video transects with the underwater vehicle ROTV Politolana from the IEO. The processing and analysis of the geophysical information has allowed obtaining a detailed bathymetry grid of 10 × 10 m, from which the first morphosedimentary characterization of the system of tributary canyons to the E-W trending main canyon and its interfluves has been made. One of the main features of this canyon system is the presence of a large pockmark field on adjacent platforms between canyons, located between 500 and 1000 m water depth. Within this field, pockmarks are shown as circular to elliptical depressions, most likely related to gas rich-fluid emissions to the subsurface.Versión del edito

MAPPING COMMUNITY INTEREST HABITATS IN THE COLUMBRETES ARCHIPELAGO, AN EXTRAORDINARY HOT SPOT OF BIODIVERSITY

The Columbretes Archipelago and their submerged surroundings are part of an unusual, Pleistocene volcanic field located in the Western Mediterranean designated as a Site of Community Importance (SCI) of the Natura 2000 Network. In the present study, 4 benthic habitats of community interest (1110, 1170, 1180 and 8330) have been identified by analyzing several sources of information. Generalized additive models (GAMs) have been used to model the potential distribution of reefs (1170) and maërl beds (1110). Our results highlight the diversity and extent of these habitats and allow comparisons to other marine SCIs of Spain. This can be attributed to the variability of the environment of this site. The Columbretes Islands combine a relatively shallow environment with volcanic structures, hydrothermalism with active degassing, current-driven sedimentary lobes and the influence of inland flows. Understanding high biodiversity spots is crucial as they offer natural laboratories to describe how ecosystems respond to the effects of global change. The knowledge obtained will be of paramount importance for the conservation of species and habitats. Furthermore, it will establish a baseline for future monitoring and assist in the development of effective management plans

IVRIPARC project: a method for assessing the impact of global change on geoheritage of the Canary Islands national parks (Spain)

El patrimonio geológico y la geodiversidad de los parques nacionales contribuyen, junto con la biodiversidad, para que sean espacios naturales protegidos únicos en el país, pero también únicos a nivel mundial. El patrimonio geológico es de carácter no renovable, de tal forma que, si se pierden o degradan, lo hacen para siempre. Ante el escenario del cambio global, el patrimonio geológico de los parques nacionales canarios es muy vulnerable a los impactos rovocados por los cambios en la temperatura, avenidas torrenciales, tormentas extremas, sequías, desertificación y ascenso del nivel del mar, fundamentalmente, y a los impactos derivados de la actividad humana. Estos fenómenos provocan la activación de procesos geológicos que afectan directamente a su conservación, de tal forma que es necesario identificar los Lugares de Interés Geológico más amenazados, evaluar su incidencia y establecer los indicadores a escala de cada parque nacional para realizar su seguimiento. Conocer el estado de conservación actual, su vulnerabilidad y sus amenazas directas contribuirá a la gestión de los parques para el proceso de adaptación y mitigación del cambio global.The geoheritage and geodiversity of the national parks contribute, together with biodiversity, to make them protected natural areas that are unique in Spain, but also unique worldwide. Geoheritage is non-renewable and if it is lost or degraded it does so forever. Under the Global Change and Climate Change scenario, the geoheritage of the Canary national parks is highly vulnerable to the impacts caused by changes in temperature, flash floods, extreme storms, droughts, desertification, fires and sea level rise, fundamentally and to the impacts directly derived from human activity. These phenomena trigger the activation of geological processes that directly affect their conservation, in such a way that it is necessary to identify the geosites most threatened, to evaluate their impact and to establish the indicators at the scale of each national park for monitoring them. The knowledge of the current conservation status of geoheritage, its vulnerability and its direct threats will contribute to the management of the national parks for the process of adaptation and mitigation of Global Change.Depto. de Geodinámica, Estratigrafía y PaleontologíaDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEOrganismo Autónomo de Parques Nacionalespu

Monitoring the complex benthic habitat on semi-dark underwater marine caves using photogrammetry-based 3D reconstructions

Marine caves are dark environments considered a priority habitat for conservation included in the EU Habitats Directive (H8330). They harbor fragile benthic communities and represent a major reservoir of marine biodiversity. However, there is a lack of knowledge of these habitats due to the difficulties of creating detailed benthic maps and characterizing the biodiversity, structure, and dynamics of their communities. The uniqueness of marine caves fosters their popularity among recreational divers, who can cause disturbances through abrasion of the biota, resuspension of sediment, and accumulation of exhaled air bubbles in the caves' ceilings. This study aims to build a monitoring framework to characterize the structure and temporal dynamics of this complex habitat using Structurefrom- Motion (SfM) photogrammetry. SfM is a novel, non-invasive technique that allows a major advancement in the monitoring of changes in the cave’s community assemblages. This method relies on images acquired by 4K video footage to build fine-scaled 3D digital models of the substrate using overlapping imagery. For this study, we combined SfM photogrammetry and photo quadrats extracted from the video recordings. We evaluate the effectiveness of this methodology in a marine cave highly frequented by divers, located in Illa de l’Aire (Balearic Islands, Spain), and carried out two surveys before and after the diving season (2019-2021). As a result, we found a loss of 25 colonies of bryozoans with fragile skeletons, like Schizoretepora sp., and 8 individual sponges with globose morphotypes. Our results indicate that this methodology enables accurate and efficient monitoring of benthic communities in underwater caves that allow us to better understand their dynamics and, therefore, to develop the need management measures

Variability in sediment particle size, mineralogy, and Fe mode of occurrence across dust-source inland drainage basins: the case of the lower Drâa Valley, Morocco

The effects of desert dust upon climate and ecosystems depend strongly on its particle size and size-resolved mineralogical composition. However, there is very limited quantitative knowledge on the particle size and composition of the parent sediments along with their variability within dust-source regions, particularly in dust emission hotspots. The lower Drâa Valley, an inland drainage basin and dust hotspot region located in the Moroccan Sahara, was chosen for a comprehensive analysis of sediment particle size and mineralogy. Different sediment type samples (n= 42) were collected, including paleo-sediments, paved surfaces, crusts, and dunes, and analysed for particle-size distribution (minimally and fully dispersed samples) and mineralogy. Furthermore, Fe sequential wet extraction was carried out to characterise the modes of occurrence of Fe, including Fe in Fe (oxyhydr)oxides, mainly from goethite and hematite, which are key to dust radiative effects; the poorly crystalline pool of Fe (readily exchangeable ionic Fe and Fe in nano-Fe oxides), relevant to dust impacts upon ocean biogeochemistry; and structural Fe. Results yield a conceptual model where both particle size and mineralogy are segregated by transport and deposition of sediments during runoff of water across the basin and by the precipitation of salts, which causes a sedimentary fractionation. The proportion of coarser particles enriched in quartz is higher in the highlands, while that of finer particles rich in clay, carbonates, and Fe oxides is higher in the lowland dust emission hotspots. There, when water ponds and evaporates, secondary carbonates and salts precipitate, and the clays are enriched in readily exchangeable ionic Fe, due to sorption of dissolved Fe by illite. The results differ from currently available mineralogical atlases and highlight the need for observationally constrained global high-resolution mineralogical data for mineral-speciated dust modelling. The dataset obtained represents an important resource for future evaluation of surface mineralogy retrievals from spaceborne spectroscopy