Is spillover relevant for hydrogen adsorption and storage in porous carbons doped with palladium nanoparticles?

Producción CientíficaExperiments have shown that the efficiency of nanoporous carbons to store hydrogen becomes enhanced by doping the material with metallic nanoparticles. In particular, doping with palladium has been used with success. The hypothesis to justify the enhancement has been that the Pd nanoparticles dissociate the hydrogen molecules and then the hydrogen atoms spill over the carbon substrate, where the hydrogen is retained. To test this hypothesis we have performed ab initio molecular dynamics simulations of the deposition of molecular hydrogen on Pd nanoparticles (Pd6 and Pd13) supported on graphene, which is a good model for the wall of a carbon nanopore. Three channels have been identified in the simulations: bouncing off the molecule, molecular adsorption, and dissociation of the molecule in two H atoms. The relative percentage of those channels is sensitive to the size of the Pd particle. Dissociation occurs more frequently on Pd13 and it generally takes place on the lateral regions of the Pd particles. However, in our simulations, we have not found a single case of H atoms or H2 molecules spilling over the carbon substrate. We have also tested the situation when several H atoms are preadsorbed on the Pd6 and Pd13 particles and found that not a single dissociation event occurs on these H-saturated nanoparticles. These results lead us to cast strong doubts on the validity of the spillover mechanism for explaining the enhancement of hydrogen adsorption on porous carbons doped with transition metal nanoparticles.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA050U14

Stylasterid corals: a new paleotemperature archive

Stylasterids are a ubiquitous deep-sea coral taxon that build their skeletons from either calcite, aragonite, or both. Yet, robust geochemical proxy data from these corals are limited. In this study, 95 modern stylasterids, spanning a wide range of depths (63 to 2894 m) and ambient seawater temperatures (0 to 17 °C), were tested for their potential use as paleoceanographic archives. Stable oxygen and carbon isotopic composition (O and C) were measured from the main trunk of all specimens and five specimens were further sub-sampled to assess internal chemical variability. The isotope data show non-equilibrium precipitation from seawater for both O and C, with the growing tips of colonies yielding the isotopically lowest values. Overall, the calcitic corals showed lower isotope values for O and C than aragonitic specimens. Within the aragonite corals, we present a O:temperature calibration that exhibits a significant linear relationship with the equation Ocoral-seawater = −0.22(°C) + 3.33(±0.06) across a temperature range of 0 to 30 °C, using samples from this study and published data. This work highlights the potential application of stylasterid coral O data to reconstruct paleo seawater temperature

Integrative taxonomy of <em>Tethya</em>: description of four new species based on morphology, phylogeny and microbiome diversity

The genus Tethya, one of the most iconic groups in the phylum Porifera. includes nearly 100 valid species. Tethya shows a nearly cosmopolitan distribution, and thus this clade could help elucidate global mechanisms of speciation in sponges. Contrasting with many other marine organisms, Tethya peaks in diversity in the temperate region, with only ∼30% of diversity occurring in the tropics. This pattern may however be related to a lack of studies in the tropics, masked by dubious taxonomic identifications. To address this question, we studied new collections from the Western Atlantic (Caribbean and Brazil) and the Northeastern Atlantic, as well as museum material from the Indian Ocean. Combining morphological investigation with molecular phylogenetics and the study of the sponge’s microbial communities, we conclude that four constitute new species that we describe here: Tethya martini Riesgo, Giribet, & Santodomingo, sp. nov.; Tethya simoni Santodomingo, Zea, & Riesgo, sp. nov.; Tethya erici Díez-Vives, Santodomingo, Moles, & Riesgo, sp. nov.; Tethya orioni Kenny, Santodomingo & Riesgo, sp. nov. Some species thought to be widespread (e.g., T. aurantium and T. seychellensis), each represent multiple species with unique geographic distributions. A phylogenetic analysis of Tethya (based on COI and 28S rRNA sequence data) recovered five main clades, which were also characterized by distinct prokaryotic communities. This suggests that microbiomes could be used as a guide for taxonomic identification in Tethya. We finally explored the existence of a phylosymbiotic pattern in sponges at different levels of prokaryotic taxonomic resolution (i.e., at phylum, class, and genus-level analysis of prokaryotes). Remarkably, our analysis revealed high levels of coevolution of Tethya and their associated microbial communities, even when microbiomes were analysed at the genus level. Our findings support the use of an integrative approach to better understand the evolutionary history of sponges

Association between isotretinoin use and central retinal vein occlusion in an adolescent with minor predisposition for thrombotic incidents: a case report

<p>Abstract</p> <p>Introduction</p> <p>We report an adolescent boy with minimal pre-existing risk for thromboses who suffered central retinal vein occlusion associated with isotretinoin use for acne. To the best of our knowledge, this is the first well documented case of this association.</p> <p>Case presentation</p> <p>An otherwise healthy 17-year-old white man who was treated with systemic isotretinoin for recalcitrant acne was referred with central retinal vein occlusion in one eye. Although a detailed investigation was negative, DNA testing revealed that the patient was a heterozygous carrier of the G20210A mutation of the prothrombin gene. Despite the fact that this particular mutation is thought to represent only a minor risk factor for thromboses, it is probable that isotretinoin treatment greatly increased the risk of a vaso-occlusive incident in this patient.</p> <p>Conclusion</p> <p>Isotretinoin use may be associated with sight- and life-threatening thrombotic adverse effects even in young patients with otherwise minimal thrombophilic risk. Physicians should be aware of such potential dangers.</p

Calcitization of aragonitic bryozoans in Cenozoic tropical carbonates from East Kalimantan, Indonesia

© The Author(s) 2016. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The file attached is the published version of the article

Global trends in myopia management attitudes and strategies in clinical practice

PURPOSE: Myopia is a global public health issue; however, no information exists as to how potential myopia retardation strategies are being adopted globally. METHODS: A self-administrated, internet-based questionnaire was distributed in six languages, through professional bodies to eye care practitioners globally. The questions examined: awareness of increasing myopia prevalence, perceived efficacy and adoption of available strategies, and reasons for not adopting specific strategies. RESULTS: Of the 971 respondents, concern was higher (median 9/10) in Asia than in any other continent (7/10, p<0.001) and they considered themselves more active in implementing myopia control strategies (8/10) than Australasia and Europe (7/10), with North (4/10) and South America (5/10) being least proactive (p<0.001). Orthokeratology was perceived to be the most effective method of myopia control, followed by increased time outdoors and pharmaceutical approaches, with under-correction and single vision spectacles felt to be the least effective (p<0.05). Although significant intra-regional differences existed, overall most practitioners 67.5 (±37.8)% prescribed single vision spectacles or contact lenses as the primary mode of correction for myopic patients. The main justifications for their reluctance to prescribe alternatives to single vision refractive corrections were increased cost (35.6%), inadequate information (33.3%) and the unpredictability of outcomes (28.2%). CONCLUSIONS: Regardless of practitioners' awareness of the efficacy of myopia control techniques, the vast majority still prescribe single vision interventions to young myopes. In view of the increasing prevalence of myopia and existing evidence for interventions to slow myopia progression, clear guidelines for myopia management need to be established

Optical Interventions for Myopia Control

Myopia is a common eye problem that is becoming more prevalent worldwide, particularly in East Asia. The cost of long-term care for myopia-related eye diseases significantly impacts the respective economies and places a great burden on the public health services. There is no doubt that myopia is a major East Asian public health concern and a significant concern globally, and effective control of myopia would help to alleviate the costs that are related to this problem. Currently, there are many types of optical interventions involving the use of spectacle lenses or contact lenses to slow down myopia progression in children. However, none of these myopia control methods have been proven to stop the development or progression of myopia completely and each method has their own limitations. Orthokeratology, soft bifocal contact lenses, prismatic bifocals, and myopic defocus incorporated spectacle lenses have all been shown to have clinically meaningful reductions in myopia progression ranging from 45% to 60%. Although pharmaceutical agents such as atropine have relatively better myopia control effects than optical methods, the associated side effects and uncertainty in the safety of long-term atropine use may hinder its widespread clinical application. Optical interventions are non-invasive and have become more popular compared to pharmaceutical treatments. This chapter provides an overview of the optical interventions for slowing myopia progression and their effectiveness in myopia control. Other myopia control methods will also be discussed briefly

Distribution of Endogenous Farnesyl Pyrophosphate and Four Species of Lysophosphatidic Acid in Rodent Brain

Lysophosphatidic acid (LPA) is the umbrella term for lipid signaling molecules that share structural homology and activate the family of LPA receptors. Farnesyl Pyrophosphate (FPP) is commonly known as an intermediate in the synthesis of steroid hormones; however, its function as a signaling lipid is beginning to be explored. FPP was recently shown to an activator of the G-protein coupled receptor 92 (also known as LPA5) of the calcium channel TRPV3. The LPA receptors (including GPR92) are associated with the signal transduction of noxious stimuli, however, very little is known about the distribution of their signaling ligands (LPAs and FPP) in the brain. Here, using HPLC/MS/MS, we developed extraction and analytical methods for measuring levels of FPP and 4 species of LPA (palmitoyl, stearoyl, oleoyl and arachidonoyl-sn-glycerol-3 phosphate) in rodent brain. Relative distributions of each of the five compounds was significantly different across the brain suggesting divergent functionality for each as signaling molecules based on where and how much of each is being produced. Brainstem, midbrain, and thalamus contained the highest levels measured for each compound, though none in the same ratios while relatively small amounts were produced in cortex and cerebellum. These data provide a framework for investigations into functional relationships of these lipid ligands in specific brain areas, many of which are associated with the perception of pain

Implications of population connectivity studies for the design of marine protected areas in the deep sea: An example of a demosponge from the Clarion-Clipperton Zone

The abyssal demosponge Plenaster craigi inhabits the Clarion‐Clipperton Zone (CCZ) in the northeast Pacific, a region with abundant seafloor polymetallic nodules with potential mining interest. Since P. craigi is a very abundant encrusting sponge on nodules, understanding its genetic diversity and connectivity could provide important insights into extinction risks and design of marine protected areas. Our main aim was to assess the effectiveness of the Area of Particular Environmental Interest 6 (APEI‐6) as a potential genetic reservoir for three adjacent mining exploration contract areas (UK‐1A, UK‐1B and OMS‐1A). As in many other sponges, COI showed extremely low variability even for samples ~900 km apart. Conversely, the 168 individuals of P. craigi, genotyped for 11 microsatellite markers, provided strong genetic structure at large geographical scales not explained by isolation by distance (IBD). Interestingly, we detected molecular affinities between samples from APEI‐6 and UK‐1A, despite being separated ~800 km. Although our migration analysis inferred very little progeny dispersal of individuals between areas, the major differentiation of OMS‐1A from the other areas might be explained by the occurrence of predominantly northeasterly transport predicted by the HYCOM hydrodynamic model. Our study suggests that although APEI‐6 does serve a conservation role, with species connectivity to the exploration areas, it is on its own inadequate as a propagule source for P. craigi for the entire eastern portion of the CCZ. Our new data suggest that an APEI located to the east and/or the south of the UK‐1, OMS‐1, BGR, TOML and NORI areas would be highly valuable

Bryozoans are Major Modern Builders of South Atlantic Oddly Shaped Reefs

Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-27961-6.In major modern reef regions, either in the Indo-Pacific or the Caribbean, scleractinian corals are described as the main reef framework builders, often associated with crustose coralline algae. We used underwater cores to investigate Late Holocene reef growth and characterise the main framework builders in the Abrolhos Shelf, the largest and richest modern tropical reef complex in the South Western Atlantic, a scientifically underexplored reef province. Rather than a typical coralgal reef, our results show a complex framework building system dominated by bryozoans. Bryozoans were major components in all cores and age intervals (2,000 yrs BP), accounting for up to 44% of the reef framework, while crustose coralline algae and coral accounted for less than 28 and 23%, respectively. Reef accretion rates varied from 2.7 to 0.9 mm yr−1, which are similar to typical coralgal reefs. Bryozoan functional groups encompassed 20 taxa and Celleporaria atlantica (Busk, 1884) dominated the framework at all cores. While the prevalent mesotrophic conditions may have driven suspensionfeeders’ dominance over photoautotrophs and mixotrophs, we propose that a combination of historical factors with the low storm-disturbance regime of the tropical South Atlantic also contributed to the region’s low diversity, and underlies the unique mushroom shape of the Abrolhos pinnacles.We thank CNPq/FAPES-Sisbiota/PELD, CAPES/IODP, CAPES/Ciências do Mar, and ANP/Brasoil for long term project funding. We also thank ICMBio for research permits and field logistic support, and Conservation International for providing and authorizing the use of the IKONOS image. JMW and JCB are International Visiting Researcher at UFES and JBRJ, supported by the Science Without Borders program. Zá Cajueiro provided invaluable field support and Ronaldo Francini, Carlos Janovitch and Lucio Engler helped in the drilling operations. This is a contribution from the Rede Abrolhos (abrolhos.org)