264 results on '"Rosa Menéndez"'
Search Results
2. Population synchrony indicates functional connectivity in a threatened sedentary butterfly
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Alex Blomfield, Rosa Menéndez, and Andrew Wilby
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Ecology, Evolution, Behavior and Systematics - Abstract
Dispersal is a key influence on species’ persistence, particularly in the context of habitat fragmentation and environmental change. Previously, residual population synchrony has been demonstrated to be an effective proxy for dispersal in mobile butterflies (Powney et al. 2012). Here, we highlight the utility and limitations of population synchrony as an indicator of functional connectivity and persistence, at a range of spatial scales, in a specialist, sedentary butterfly. While at the local scale, population synchrony is likely indicative of dispersal in the pearl-bordered fritillary, Boloria euphrosyne, over larger scales, habitat is likely to influence population dynamics. Although declines in local-scale synchrony conformed to typical movement in this species, synchrony showed no significant trend with distance when studied at larger (between-site) scales. By focusing on specific site comparisons, we draw the conclusion that heterogeneity in habitat successional stage drives asynchrony between sites at larger distances and is, therefore, likely to be a more important driver of population dynamics over large distances than dispersal. Within-site assessments of synchrony highlight differences in dispersal based on habitat type, with movement shown to be most inhibited between transect sections with contrasting habitat permeability. While synchrony has implications for metapopulation stability and extinction risk, no significant difference was found in average site synchrony between sites that had gone extinct during the study period and those remaining occupied. We demonstrate that population synchrony may be used to assess local-scale movement between sedentary populations, as well as to understand barriers to dispersal and guide conservation management.
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- 2023
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3. Genetic diversity and differentiation of isolated rear‐edge populations of a cold adapted butterfly, Erebia aethiops , in Britain
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Lucy R. Gunson, Michael R. Roberts, and Rosa Menéndez
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Insect Science ,Ecology, Evolution, Behavior and Systematics - Published
- 2023
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4. A trait-based framework for dung beetle functional ecology
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Indradatta deCastro‐Arrazola, Nigel R. Andrew, Matty P. Berg, Alva Curtsdotter, Jean‐Pierre Lumaret, Rosa Menéndez, Marco Moretti, Beatrice Nervo, Elizabeth S. Nichols, Francisco Sánchez‐Piñero, Ana M. C. Santos, Kimberly S. Sheldon, Eleanor M. Slade, Joaquín Hortal, UAM. Departamento de Ecología, Ministerio de Ciencia e Innovación (España), and Repositório da Universidade de Lisboa
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Trait–function relationships ,ecosystem engineers ,trait–function relationships ,Ecosystem processes ,Biología y Biomedicina / Biología ,response traits ,multifunctionality ,effect traits ,Ecosystem engineers ,Effect traits ,Multifunctionality ,Animal Science and Zoology ,Scarabaeoidea ,Response traits ,Ecology, Evolution, Behavior and Systematics ,ecosystem processes - Abstract
Traits are key for understanding the environmental responses and ecological roles of organisms. Trait approaches to functional ecology are well established for plants, whereas consistent frameworks for animal groups are less developed. Here we suggest a framework for the study of the functional ecology of animals from a trait-based response–effect approach, using dung beetles as model system. Dung beetles are a key group of decomposers that are important for many ecosystem processes. The lack of a trait-based framework tailored to this group has limited the use of traits in dung beetle functional ecology. We review which dung beetle traits respond to the environment and affect ecosystem processes, covering the wide range of spatial, temporal and biological scales at which they are involved. Dung beetles show trait-based responses to variation in temperature, water, soil properties, trophic resources, light, vegetation structure, competition, predation and parasitism. Dung beetles' influence on ecosystem processes includes trait-mediated effects on nutrient cycling, bioturbation, plant growth, seed dispersal, other dung-based organisms and parasite transmission, as well as some cases of pollination and predation. We identify 66 dung beetle traits that are either response or effect traits, or both, pertaining to six main categories: morphology, feeding, reproduction, physiology, activity and movement. Several traits pertain to more than one category, in particular dung relocation behaviour during nesting or feeding. We also identify 136 trait–response and 77 trait–effect relationships in dung beetles. No response to environmental stressors nor effect over ecological processes were related with traits of a single category. This highlights the interrelationship between the traits shaping body-plans, the multi-functionality of traits, and their role linking responses to the environment and effects on the ecosystem. Despite current developments in dung beetle functional ecology, many knowledge gaps remain, and there are biases towards certain traits, functions, taxonomic groups and regions. Our framework provides the foundations for the thorough development of trait-based dung beetle ecology. It also serves as an example framework for other taxa., Spanish Ministry of Science and Innovation, FPI grant BES2012-054353, Ramón y Cajal Fellowship (RYC2020-029407-I). Spanish Agencia Estatal de Investigación Projects CGL2011-29317, PID2019-106840GB-C21/AEI/10.13039/501100011033.
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- 2023
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5. Abandonment of cultural landscapes: butterfly communities track the advance of forest over grasslands
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Amparo Mora, Andrew Wilby, and Rosa Menéndez
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Ecology ,Insect Science ,Animal Science and Zoology ,Nature and Landscape Conservation - Abstract
Abstract Rural landscapes in Europe have suffered considerable land-use change in the last 50 years, with agricultural intensification in western regions and land abandonment in eastern and southern regions. The negative impacts of agricultural intensification on butterflies and other insects in western Europe have been well studied. However, less is known about the impacts of abandonment on mountain and humid areas of eastern and southern Europe, where landscapes have remained more natural. We sampled butterfly communities in the Picos de Europa National Park (Spain), a region which is undergoing a process of rural abandonment. 19 hay meadows with different periods of abandonment were studied (long-term 18 years or mid-term abandoned, 3–7 years) and compared to meadows continuously managed in a traditional way. We examined how local meadow characteristics and landscape variables affected butterfly community response to abandonment. Butterfly communities were affected by abandonment, with an overall increase in the density of individuals in the long term. Community composition appears to undergo major change over time, with a species turnover of around 50% in the first few years of abandonment, rising to around 70% after 18 years of abandonment. There was a tendency for species with higher preference for closed habitats to increase their densities as time since abandonment proceeded. Landscape variables had a major impact on butterfly communities, stronger than the effect of meadow management. Community preference for closed habitats was associated with higher forest cover in the surroundings of the meadows, but heterogeneous landscapes (in their composition or configuration) mitigated this effect. Implications for insect conservation Our findings suggest that we should ensure that communities have time to react to the diverse stressors imposed by global change. Facilitating survival to all kinds of functional and taxonomic groups implies promoting landscape heterogeneity and connectivity.
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- 2021
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6. Patterns and determinants of plant, butterfly and beetle diversity reveal optimal city grassland management and green urban planning
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Jakub Horák, Lenka Šafářová, Jiří Trombik, and Rosa Menéndez
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Ecology ,Soil Science ,Forestry - Abstract
Urban landscapes are places with high interaction between humans and nature, and the benefit of maintaining their biodiversity to enhance human wellbeing is becoming clear. There is, therefore, an urgent need for understanding what influences biodiversity in cities to inform and influence urban landscape planning. We used a multi-taxa approach (plants, butterflies, and beetles) to assess the influence of the fragmented landscape of a European city, Pardubice (Czech Republic), on the biodiversity of urban grasslands. We randomly selected 40 urban grasslands and were interested in the influences of site and land-use characteristics on biodiversity. The influence of the land-use around the grasslands was analyzed along a gradient of spatial scales (i.e., the cover of land-use types within circular buffer zones of 250, 500, and 750 m around the study grasslands). We found that species richness of the three study taxa was positively influenced by the size of the grassland (measured as grassland perimeter). Butterflies were also negatively affected by increasing management intensity. Plants and beetles were influenced by the land-use type, with plant species richness positively affected by the extent of urban greenings (i.e., green areas such as urban parks, gardens, and sport grounds), and beetle species richness negatively affected by the extent of built-up areas in the grassland surroundings. Biodiversity responses to urbanization partly differed among the studied taxa, indicating different demands of specific groups, but the demands were not conflicting and instead, often complemented each other. Consideration of the three key factors influencing biodiversity identified here (grassland extent, land-use in the surroundings, and management intensity) would provide the optimal options for maintaining city biodiversity. Protecting current urban grasslands from development and restricting construction in their surroundings, restoring city wilderness areas using urban spatial planning, and setting up butterfly-friendly management regimes (e.g., mowing in mosaic) could all be future options to help enhance biodiversity in cities.
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- 2022
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7. Bait preferences of Australian dung beetles (Coleoptera: Scarabaeidae) in tropical and subtropical Queensland forests
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Rosa Menéndez, Kathryn M Ebert, Geoff B. Monteith, and David J. Merritt
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Scarabaeidae ,Ecology ,Fauna ,Detritivore ,Rainforest ,Biology ,Generalist and specialist species ,biology.organism_classification ,Pitfall trap ,Insect Science ,Scarabaeinae ,Agronomy and Crop Science ,Ecology, Evolution, Behavior and Systematics ,Dung beetle - Abstract
Dung beetles (Scarabaeinae) are mainly coprophagous. Globally, many species co-exist with large mammalian fauna in grasslands and savannahs. However, tropical and subtropical rainforests, where large herbivorous mammals are scarce, support numerous dung beetle species. Many rainforest dung beetles have been shown to be generalist saprophages or specialists on non-dung food resources. In Australian rainforests, observations of native dung beetles have indicated that some species are attracted to other resources such as fruit or fungi, although the extent to which this occurs is not known. To learn more about the diet breadth of Australian native rainforest dung beetles, we assessed their attraction to a range of baits, including two types of dung, four types of carrion from both vertebrates and invertebrates, three types of rotting fruit and rotting mushrooms. We primarily surveyed rainforest sites but included two dry open-forest sites for comparisons. Of the two groups of Australian native dung beetles (Onthophagini and Australian endemic genera), the latter dominated the rainforest dung beetle fauna and were attracted to a greater variety of baits compared with Onthophagini. The Onthophagini were dominant in open forest and were more likely to be attracted to a particular bait type, primarily dung. Our findings suggest that many of the species belonging to the ‘Australian endemic genera’ are generalist feeders and their ability to utilise a range of food resources contributes to their abundance and diversity in Australian rainforests.
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- 2019
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8. Dung beetle diversity and functions suggest no major impacts of cattle grazing in the Brazilian Pantanal wetlands
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Rosa Menéndez, Julio Louzada, Rodrigo Fagundes Braga, and César M. A. Correa
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0106 biological sciences ,Biomass (ecology) ,geography ,geography.geographical_feature_category ,Ecology ,biology ,business.industry ,Wetland ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,010602 entomology ,Abundance (ecology) ,Insect Science ,Livestock ,Species richness ,Scarabaeinae ,business ,Bioturbation ,Dung beetle - Abstract
1. Dung beetles perform relevant ecological functions in pastures, such as dung removal and parasite control. Livestock farming is the main economic activity in the Brazilian Pantanal. However, the impact of cattle grazing on the Pantanal's native dung beetle community, and functions performed by them, is still unknown. 2. This study evaluated the effects of cattle activity on dung beetle community attributes (richness, abundance, biomass, composition, and functional group) as well as their ecological functions (dung removal and soil bioturbation) in the Pantanal. In January/February 2016, dung beetles were sampled and their ecological functions measured in 16 sites of native grasslands in Aquidauana, Mato Grosso do Sul, Brazil, 10 areas regularly grazed by cattle and six control ungrazed areas (> 20 years of abandonment). 3. In all, 1169 individuals from 30 species of dung beetles were collected. Although abundance, species richness, and biomass did not differ between grasslands with and without cattle activity, species composition and functional groups differed among systems. Large roller beetles were absent from non-cattle grasslands, and the abundance, richness, and biomass of medium roller beetles was higher in those systems. 4. Despite causing changes in species/functional group composition, the results of this study show that a density compensation of functional groups in cattle-grazed natural grasslands seems to have conserved the ecological functions (dung removal and soil bioturbation), with no significant differences between systems. 5. Therefore, these results provide evidence that cattle breeding in natural grasslands of the Brazilian Pantanal can integrate livestock production with the conservation of the dung beetle community and its ecological functions. © 2019 The Royal Entomological Society
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- 2019
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9. Influence of graphene sheet properties as supports of iridium-based N-heterocyclic carbene hybrid materials for water oxidation electrocatalysis
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María González-Ingelmo, Gloria Subías, Jesús J. Pérez-Torrente, Beatriz Sánchez-Page, Javier Blasco, M. Victoria Jiménez, Laura Fernández, Rosa Menéndez, Zoraida González, Marcos Granda, Ana M. Pérez-Mas, Patricia Álvarez, Ministerio de Economía y Competitividad (España), Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Gobierno de Aragón, and Principado de Asturias
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Water oxidation ,chemistry.chemical_element ,010402 general chemistry ,Electrocatalyst ,Iridium ,01 natural sciences ,Biochemistry ,law.invention ,Catalysis ,Inorganic Chemistry ,chemistry.chemical_compound ,law ,Materials Chemistry ,Graphite ,Physical and Theoretical Chemistry ,010405 organic chemistry ,Graphene ,Chemistry ,Ligand ,Organic Chemistry ,Graphene supports ,0104 chemical sciences ,Crystallography ,Hybrid material ,Carbene - Abstract
The effect of the structural properties of graphene materials on the local structure of –OH anchored Ir(I)–NHC complexes is herein investigated. For that, two partially reduced graphene oxides exhibiting different sheet properties due to an adequate selection of the crystalline characteristics of their parent graphite were used. The main differences among them were the size of Csp2 domains within their graphenic layers and the distribution of functional groups at the basal planes and edges. Anchoring of N-methylimidazolium moieties through the graphene –OH functional groups and subsequent formation of the Ir(I)–NHC complexes resulted in graphene-based hybrid materials. The structural differences of the support have an influence in the interaction of the supported iridium compounds with the graphene sheet. The oxygenated functional groups in the material with a smaller graphene sheet are closer leaving larger Csp2 domains in the graphene layer, favoring their interaction with the supported iridium atoms therefore displacing the chlorido ligand from the first coordination shell. In contrast, the hybrid material in which the distribution of the oxygenated functional groups within the basal planes of the graphenic layer is more homogeneous shows partial chlorido displacement. This fact has an influence on the electrocatalytic performance of the iridium-based hybrid materials as water oxidation catalysts (WOCs), exhibiting improved catalytic activity the catalyst having coordinated chlorido ligands., Financial support from the Ministerio de Ciencia e Innovación (MICINN/FEDER) under the projects CTQ2016-75884-P and RTI2018-098537-B-C22, Gobierno de Aragón/FEDER 2014–2020 “Building Europe from Aragón” (groups E42_17R and E12_20R) and Principado de Asturias/FEDER (IDI/2018/000121) are gratefully acknowledged.
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- 2021
10. Near-atomic structure of an atadenovirus reveals a conserved capsid-binding motif and intergenera variations in cementing proteins
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Carmen San Martín, Roberto Marabini, Mart Krupovic, Josué Gómez-Blanco, Rosa Menéndez-Conejero, Gabriela N. Condezo, Universidad Autónoma de Madrid (UAM), Centro Nacional de Biotecnología [Madrid] (CNB-CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Virologie des archées - Archaeal Virology, Institut Pasteur [Paris] (IP), This work is supported by the Spanish Agencia Estatal de Investigación and European Regional Development Fund (BFU2016-74868-P and PID2019-104098GB-I00/AEI/10.13039/501100011033), the Ministerio de Economía y Competitividad of Spain (BFU2013-41249-P and BIO2015-68990-REDT), and the Agencia Estatal CSIC (2019AEP045). The CNB-CSIC is further supported by a Severo Ochoa Excellence grant (SEV 2017-0712). M.K. was supported by the Emergence(s) program from City of Paris (grant MEMREMA)., Universidad Autonoma de Madrid (UAM), Institut Pasteur [Paris], UAM. Departamento de Ingeniería Informática, and Tratamiento de Señales Biomédicas (ING EPS-011)
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viruses ,Atadenovirus ,Bacteriophage ,03 medical and health sciences ,Structural Biology ,Virology ,Gene duplication ,Coat Proteins ,Research Articles ,Tropism ,030304 developmental biology ,Informática ,0303 health sciences ,Multidisciplinary ,biology ,Chemistry ,030302 biochemistry & molecular biology ,SciAdv r-articles ,biology.organism_classification ,3. Good health ,Cell biology ,Mastadenovirus ,Capsid ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,sense organs ,Research Article - Abstract
The first high-resolution structure of an adenovirus with nonmammalian host provides information on adenovirus evolution., Of five known adenovirus genera, high-resolution structures are available only for mammalian-infecting mastadenoviruses. We present the first high-resolution structure of an adenovirus with nonmammalian host: lizard atadenovirus LAdV-2. We find a large conformational difference in the internal vertex protein IIIa between mast- and atadenoviruses, induced by the presence of an extended polypeptide. This polypeptide, and α-helical clusters beneath the facet, likely correspond to genus-specific proteins LH2 and p32k. Another genus-specific protein, LH3, with a fold typical of bacteriophage tailspikes, contacts the capsid surface via a triskelion structure identical to that used by mastadenovirus protein IX, revealing a conserved capsid-binding motif and an ancient gene duplication event. Our data also suggest that mastadenovirus E1B-55 K was exapted from the atadenovirus-like LH3 protein. This work provides new information on the evolution of adenoviruses, emphasizing the importance of minor coat proteins for determining specific physicochemical properties of virions and most likely their tropism.
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- 2021
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11. How butterflies keep their cool: Physical and ecological traits influence thermoregulatory ability and population trends
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Colin Lucas, GE Hitchcock, RI Knock, Jonah M. Walker, Matt Lewis, Eleanor Bladon, Rosa Menéndez, Tom M. Fayle, Matthew P. Hayes, Steven R. Ewing, Stuart Corbett, Andrew J. Bladon, Adam McVeigh, Sam J. Buckton, Edgar C. Turner, Bladon, Andrew J [0000-0002-2677-1247], Lewis, Matthew [0000-0003-2244-4078], Bladon, Eleanor K [0000-0002-0466-0335], Ewing, Steven R [0000-0002-4599-100X], Hayes, Matthew P [0000-0001-5200-9259], Menéndez, Rosa [0000-0001-9997-5809], Walker, Jonah M [0000-0001-7355-3130], Fayle, Tom M [0000-0002-1667-1189], Turner, Edgar C [0000-0003-2715-2234], and Apollo - University of Cambridge Repository
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0106 biological sciences ,specialist ,Climate Change ,Population ,Microclimate ,Climate change ,Biology ,Generalist and specialist species ,behavioural thermoregulation ,010603 evolutionary biology ,01 natural sciences ,population trends ,Animals ,generalist ,education ,Ecology, Evolution, Behavior and Systematics ,Ecosystem ,education.field_of_study ,butterflies ,Ecology ,010604 marine biology & hydrobiology ,Temperature ,Interspecific competition ,Behavioural thermoregulation ,Cold Temperature ,Habitat ,Butterfly ,Animal Science and Zoology ,microclimate ,Body Temperature Regulation - Abstract
Understanding which factors influence the ability of individuals to respond to changing temperatures is fundamental to species conservation under climate change.\ud \ud We investigated how a community of butterflies responded to fine-scale changes in air temperature, and whether species-specific responses were predicted by ecological or morphological traits.\ud \ud Using data collected across a UK reserve network, we investigated the ability of 29 butterfly species to buffer thoracic temperature against changes in air temperature. First, we tested whether differences were attributable to taxonomic family, morphology or habitat association. We then investigated the relative importance of two buffering mechanisms: behavioural thermoregulation versus fine-scale microclimate selection. Finally, we tested whether species' responses to changing temperatures predicted their population trends from a UK-wide dataset.\ud \ud We found significant interspecific variation in buffering ability, which varied between families and increased with wing length. We also found interspecific differences in the relative importance of the two buffering mechanisms, with species relying on microclimate selection suffering larger population declines over the last 40 years than those that could alter their temperature behaviourally.\ud \ud Our results highlight the importance of understanding how different species respond to fine-scale temperature variation, and the value of taking microclimate into account in conservation management to ensure favourable conditions are maintained for temperature-sensitive species.
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- 2020
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12. Vegetation composition and structure are important predictors of oviposition site selection in an alpine butterfly, the Mountain Ringlet Erebia epiphron
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L. Schofield, Rosa Menéndez, Steven R. Ewing, and Richard B. Bradbury
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0106 biological sciences ,Ecology ,Tussock ,fungi ,Biodiversity ,Microclimate ,Plant litter ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,010602 entomology ,Habitat ,Animal ecology ,Insect Science ,Butterfly ,Animal Science and Zoology ,Festuca ovina ,Nature and Landscape Conservation - Abstract
Knowledge of species’ ecological requirements is key for designing effective conservation management. In butterflies, the needs of larval stages are often the most specialised part of the life-cycle, but for many species information on this is lacking. The Mountain Ringlet Erebia epiphron is a cold-adapted butterfly found in alpine grasslands in mountainous regions of Europe. Efforts to devise conservation strategies for this climate change-threatened species are hampered due to its basic ecology being poorly understood. Here, we describe a study on the autecology of Mountain Ringlets at sites across its British distribution, focusing on the habitat preferences of egg-laying females as a proxy for larval preferences. Female Mountain Ringlets placed their eggs predominantly on Nardus stricta and Festuca ovina, but also on several other host plant species, suggesting larvae may be more broadly polyphagous than previously realised. Sites chosen for eggs had higher abundance of larval host plants, intermediate leaf litter cover, and lower cover of grass tussocks than random locations, as well as a shorter and sparser grass sward. Although the main host plant is ubiquitous in upland areas of Britain, our findings suggest that this butterfly’s egg and larval stages have specialised ecological requirements, requiring specific microhabitat features characterised by a narrow range of vegetation composition and structural characteristics. Many habitat associations are liable to be explicable as adaptations to ensure placement of eggs and larvae in sites within optimal (warm or buffered) microclimates. We tentatively suggest that the distribution of Mountain Ringlets in the landscape is thermally-constrained.
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- 2020
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13. Successional trajectory of dung beetle communities in a tropical grassy ecosystem after livestock grazing removal
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Julio Louzada, Rosa Menéndez, César M. A. Correa, Lívia Dorneles Audino, Rodrigo Fagundes Braga, and Robert Holdbrook
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0106 biological sciences ,Herbivore ,Ecology ,biology ,010604 marine biology & hydrobiology ,Chronosequence ,Biodiversity ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Abundance (ecology) ,Grazing ,Ecosystem ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Dung beetle - Abstract
Grazing by large herbivorous mammals is still a structuring force in tropical grassy ecosystems, and cattle grazing is one of the main economic activities carried out in these ecosystems in modern times. Therefore, understanding the impacts of cattle grazing removal on biodiversity may be a key step for conservation of this ecosystem. Here, we studied the successional trajectory of dung beetle communities in a tropical grassy ecosystem after cattle removal. For this, we assessed the patterns of dung beetle taxonomic and functional diversity of 14 natural grasslands with distinct cattle grazing removal ages (from 3 months to 22 years) along a chronosequence, applying the space-for-time substitution method. Our results show a strong decrease in dung beetle abundance (93 times) and species richness (6 times) in the first ten years of cattle removal. However, after ten years there is an increase in dung beetle abundance (73 times) and species richness (5 times). Taxonomic composition was also influenced by cattle removal time demonstrating the importance of cattle in the structuring of dung beetle communities in natural grasslands. In contrast, functional composition and diversity were not affected by cattle grazing removal, indicating these metrics are less sensitive to cattle absence than taxonomic diversity and composition. Our results provide evidence that cattle grazing removal, at least in the short term (10 years), may be an inefficient management tool for restoration and conservation of tropical grassy ecosystems. However, we highlight the need to investigate the reintroduction of cattle grazing after different removal times to provide complimentary information to livestock management able to integrate human use and conservation of tropical grassy ecosystems.
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- 2020
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14. Altered rainfall patterns reduce plant fitness and disrupt interactions between below‐ and aboveground insect herbivores
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Adela González-Megías, Rosa Menéndez, Martin Aguirrebengoa, and Caroline Müller
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0106 biological sciences ,Simulated precipitation ,media_common.quotation_subject ,Climate change ,Insect ,Biology ,root herbivore ,010603 evolutionary biology ,01 natural sciences ,Effects of global warming ,Root herbivore ,lcsh:QH540-549.5 ,Plant defense against herbivory ,Precipitation ,Herbivory ,Semiarid environment ,Ecology, Evolution, Behavior and Systematics ,media_common ,Trophic level ,Herbivore ,Biomass (ecology) ,Altered rainfall ,Ecology ,herbivory ,010604 marine biology & hydrobiology ,fungi ,food and beverages ,semiarid environment ,climate change ,simulated precipitation ,Brassicaceae ,root herbivory ,lcsh:Ecology ,altered rainfall - Abstract
We would like to thank Angel Caravantes Mart ınez for his help in the field and the laboratory, and Karin Djendouci for her assistance in glucosinolate extraction and identification. The authors thank Mark Lineham for revising the English, Evidence is accumulating of the disruptive effects of climate change on species interactions. However, little is known about how changes in climate patterns, such as temporal shifts in rainfall events, will affect multitrophic interactions. Here, we investigated the effects of changes in rainfall patterns on the interactions between root herbivores, a plant, and its associated aboveground insects in a semiarid region by experimentally manipulating in the field rainfall intensity and frequency. We found that a shift in rainfall severely constrained biomass acquisition and flowering of the plant Moricandia moricandioides, resulting in fitness reduction. Importantly, enhanced rainfall affected the interactions between below- and some aboveground herbivores, disrupting the positive effects of root herbivores on chewing insects. The shifts in precipitation had also plant-mediated consequences for planthoppers, the dominant sapsuckers in our study system. A combination of mechanisms involving biomass acquisition and plant defenses seemed to be responsible for the different responses of insects and their interactions with the plant. This study provides evidence that altered rainfall patterns due to climate change affect not only trophic groups differentially but also their interactions., Spanish Government CGL2011-24840 CGL2015-71634-P BBVA-P17_ECO_0021 BES-2012-059576
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- 2020
15. In-situ carboxylation of graphene by chemical vapor deposition growth for biosensing
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Carlos Prieto, Rosa Menéndez, Patricia Álvarez, Gil Gonçalves, Leo Álvarez-Fraga, Alicia de Andrés, Sandra Cortijo-Campos, Mercedes Vila, and Ministerio de Economía y Competitividad (España)
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Materials science ,Graphene ,02 engineering and technology ,General Chemistry ,Chemical vapor deposition ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,chemistry ,Chemical engineering ,Carboxylation ,law ,Surface modification ,General Materials Science ,0210 nano-technology ,Biosensor ,Sheet resistance ,Carbodiimide - Abstract
A new approach for in-situ specific functionalization of graphene with carboxylic groups through a single-step growth is presented. Depending on the fabrication parameters, it is possible to synthesize functionalized single layer or multilayer graphene. The homogeneity and functionalization degree are evaluated combining micro-Raman and XPS spectroscopies. The obtained COOH content reaches around 5%, similar to the values obtained by the other methods but with significantly lower contents of the other oxygen groups (carbonyl and hydroxyl) and of other sp defects which are detrimental for electronic transport. The obtained COOH- functionalized single-layer graphene presents optimum values of the sheet resistance, around 8 kΩ, and high mobility, around 800 cmVs. Anchoring of antibodies is demonstrated through the immobilization of IgG1–FITC by the carbodiimide method, showing that these COOH- functionalized single-layer graphene can be very promising materials for electronic sensing applications., Funding by the Spanish Ministerio de Economía y Competitividad (MINECO) under Project MAT2015-65356-C3-1-R and Comunidad de Madrid Excellence Network under Project S2013/MIT-2740 is acknowledged. S.C. acknowledges BES-2016-076440 and L.A.-F. BES-2013-062759 FPI grants from MINECO.
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- 2019
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16. Morphological changes in graphene materials caused by solvents
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Marcos Granda, Ana M. Pérez-Mas, Patricia Álvarez, Rosa Menéndez, Laura Fernández-García, Ricardo Santamaría, and Clara Blanco
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Work (thermodynamics) ,Molecular interactions ,Materials science ,Morphology (linguistics) ,Graphene ,Oxide ,Sem analysis ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Organic molecules ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Chemical engineering ,chemistry ,law ,Intramolecular force ,0210 nano-technology - Abstract
The aim of this work is to determine the changes in morphology caused in thermally reduced graphene oxide (rGO) after it has been mixed with organic molecules with different surface properties. The morphology of the dried rGO after being mixed with 16 organic solvents was evaluated using statistically SEM analysis. The results obtained indicate that this process led, in some cases, to an increase both in the number of stacked layers and in the corrugation of each rGO sheet. The largest modifications were obtained after contact with organic solvents undergoing intramolecular interactions mainly governed by the hydrogen-bonding interactions (measured as the Hansen δh parameter) and the dipole-dipole molecular interactions (expressed by the Hansen δp parameter). On the other hand, the morphology of the rGOs remained unaltered when solvents with values of δp + δh in the range 10–26 MPa1/2 were used. These results represent a useful guide for the preparation of graphene-based composites in which the morphology of the graphene in the mixture is a crucial parameter which affects their characteristics.
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- 2018
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17. Three-dimensional poly(aniline- co -pyrrole)/thermally reduced graphene oxide composite as a binder-free electrode for high-performance supercapacitors
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Zoraida González, Rosa Menéndez, Adam Moyseowicz, and Grażyna Gryglewicz
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Supercapacitor ,Materials science ,Graphene ,Mechanical Engineering ,Composite number ,Oxide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Capacitance ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Polymerization ,chemistry ,Mechanics of Materials ,law ,Electrode ,Ceramics and Composites ,Composite material ,0210 nano-technology - Abstract
Three-dimensional poly(aniline-co-pyrrole)/thermally reduced graphene oxide (PAP/TRGO) composites with different amounts of TRGO have been fabricated via an oxidative polymerization method. The three-dimensional composite containing 20 wt% TRGO exhibits enhanced electrochemical performance as an electrode active material in supercapacitors in terms of its high specific capacitance value (287 F g−1 at 0.2 A g−1) and good rate capability (205 F g−1 at 20 A g−1). The assembled symmetric supercapacitor based on the PAP/TRGO20 composite shows excellent cyclic stability with a capacitance retention of 103% after 10,000 charge-discharge cycles. These results represent a significant progress in the design of suitable binder-free electrode materials as electrochemical energy storage devices.
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- 2018
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18. Main structural features of graphene materials controlling the transport properties of epoxy resin-based composites
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R. Sanchez-Hidalgo, V. Yuste-Sanchez, Raquel Verdejo, Rosa Menéndez, Miguel A. López-Manchado, Clara Blanco, and Ministerio de Economía, Industria y Competitividad (España)
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Materials science ,Polymers and Plastics ,Polymer nanocomposite ,General Physics and Astronomy ,Graphite oxide ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,Thermal conductivity ,law ,Specific surface area ,Materials Chemistry ,Composite material ,chemistry.chemical_classification ,Graphene ,Organic Chemistry ,Polymer nanocomposites ,Epoxy ,Polymer ,021001 nanoscience & nanotechnology ,Exfoliation joint ,0104 chemical sciences ,chemistry ,visual_art ,Transport properties ,visual_art.visual_art_medium ,0210 nano-technology - Abstract
Graphene materials (GMs) are deeply studied as nanoreinforcements of polymer matrices, especially for epoxy matrices. Here, we analyze the effect of GMs on the transport properties of a poly(bisphenol A-co-epichlorohydrin) resin. In particular, we focus on the effect of the morphology, chemical composition and structure of different GMs obtained by varying the reduction temperature of the thermal/exfoliation treatment of graphite oxide synthesized by a modified Hummers method. The dispersion degree of the GMs was studied by microscopy techniques, showing a strong dependence on the specific surface area and chemical composition of the graphene material. The transport properties imposed different requirements on GMs. The thermal conductivity benefited from a high aromatic restoration. Meanwhile, the electrical conductivity required the right balance of filler/matrix interaction and aromatic restoration., The authors gratefully acknowledge the financial support of the MINECO, Spain, through the project MAT2013-48107-C3. R. Sánchez- Hidalgo thanks to MINECO, Spain for the Predoctoral grant BES-2014- 070802.
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- 2018
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19. Beneficial impact of oxygen on the electrochemical performance of dopamine sensors based on N-doped reduced graphene oxides
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Zoraida González, Rosa Menéndez, Grażyna Gryglewicz, Piotr Wiench, and B. Grzyb
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Materials science ,Inorganic chemistry ,Oxide ,Infrared spectroscopy ,chemistry.chemical_element ,02 engineering and technology ,Glassy carbon ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Oxygen ,law.invention ,chemistry.chemical_compound ,law ,Materials Chemistry ,Electrical and Electronic Engineering ,Instrumentation ,Graphene ,Metals and Alloys ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Electrochemical gas sensor ,chemistry ,Electrode ,0210 nano-technology - Abstract
Graphene-based electrochemical sensors are promising devices for direct and easy dopamine determination. In this work, N-doped reduced graphene oxides (N-rGOs) were prepared via hydrothermal treatment of graphene oxide (GO) and amitrole (3-amino-1,2,4-triazole) under different experimental conditions (varying reaction temperature and time), which resulted in each material having different oxygen content. Furthermore, the dopant nitrogen content was comparable in the three N-rGOs and it was primarily pyridinic in nature. The three synthesized N-rGOs were characterized by X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy, scanning electron microscopy, and nitrogen sorption at 77 K. Glassy carbon electrodes modified with N-rGOs were prepared and used as active electrode materials in electrochemical sensors of dopamine (DA). The optimal operational pH was determined to be 7.4, which is also the physiological value. During the electrochemical detection of DA, it was found that there is a direct relationship between the oxygen content in N-rGO and electrochemical performance of these sensors. Thus, the detection of DA in the presence of ascorbic and uric acids was more sensitive and selective when the least reduced N-rGO sample was used. The attraction between the electronegative oxygen in the graphene structure and cationic DA facilitates the adsorption process which could explain these results. However, the limit of detection (LOD) was also higher in this case due to decreased conductivity.
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- 2018
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20. Linking species thermal tolerance to elevational range shifts in upland dung beetles
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Ali J. Birkett, Rosa Menéndez, and George Alan Blackburn
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0106 biological sciences ,0301 basic medicine ,biology ,Range (biology) ,Ecology ,Global warming ,Elevation ,Climate change ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,030104 developmental biology ,Abundance (ecology) ,Ectotherm ,Period (geology) ,Ecology, Evolution, Behavior and Systematics ,Dung beetle - Abstract
Climate warming has been proposed as the main cause of the recent range shifts seen in many species. Although species’ thermal tolerances are thought to play a key role in determining responses to climate change, especially in ectotherms, empirical evidence is still limited. We investigate the connection between species’ thermal tolerances, elevational range and shifts in the lower elevational limit of dung beetle species (Coleoptera, Aphodiidea) in an upland region in the northwest of England. We measured thermal tolerances in the laboratory, and used current and historical distribution data to test specific hypotheses about the area’s three dominant species, particularly the species most likely to suffer from warming: Agollinus lapponum. We found marked differences between species in their minimum and maximum thermal tolerance and in their elevational range and patterns of abundance. Overall, differences in thermal limits among species matched the abundance patterns along the elevation gradient expected if distributions were constrained by climate. A. lapponum abundance increased with elevation and this species showed lower maximum and minimum thermal limits than Acrossus depressus, for which abundance declined with elevation. Consistent with lower tolerance to high temperature, we recorded an uphill retreat of the low elevation limit of A. lapponum (177 m over 57 years) in line with the increase in summer temperature observed in the region over the same period. Moreover, this species has been replaced at low and mid-elevations by the other two warm-tolerant species (A. depressus and Agrilinus ater). Our results provide empirical evidence that species’ thermal tolerance constrains elevational ranges and contributes to explain the observed responses to climate warming. A mechanistic understanding of how climate change directly affects species, such as the one presented here, will provide a robust base to inform predictions of how individual species and whole assemblages may change in the future.
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- 2018
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21. Role of quinoline insoluble particles during the processing of coal tars to produce graphene materials
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Patricia Álvarez, Ana M. Pérez-Mas, Ricardo Santamaría, Laura Fernández-García, Clara Blanco, Rosa Menéndez, and Marcos Granda
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Materials science ,Graphene ,General Chemical Engineering ,Sonication ,Organic Chemistry ,Quinoline ,Energy Engineering and Power Technology ,Tar ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Exfoliation joint ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Crystallinity ,Fuel Technology ,Chemical engineering ,chemistry ,law ,Organic chemistry ,Graphite ,0210 nano-technology ,Graphene oxide paper - Abstract
This work studies the utilization of a binder grade industrial tar with an inherent content in primary quinolone insoluble particles (QIs) and the correspondent free-QI tar obtained from it by a sedimentation process as raw sources of graphene materials via different preparation procedures. Graphene oxides (GOs) were prepared via the oxidation of binder tar-based graphite and subsequent sonication. The presence of QIs contributes to decreasing both the yield of the oxidation and of the exfoliation steps. This is due to the greater reactivity of QI particles towards oxidation, which modifies the distribution of the oxygen functional groups in the oxidized graphite, impeding its exfoliation. Also, as a consequence of the higher crystallinity of parent graphite without QIs, larger GO sheets were obtained in that case. On the other hand, the presence of QIs in the parent graphite facilitates its solvent exfoliation behavior in N-methyl-pyrrolidinone (NMP) to yield few layer graphene (FLG), but contributes to a decrease in the size of the flakes of the graphene materials obtained.
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- 2017
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22. Recovery of mammal diversity in tropical forests: a functional approach to measuring restoration
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Michael J. Lawes, Noel D. Preece, Helen T. Murphy, Rosa Menéndez, and Mia A. Derhé
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0106 biological sciences ,Ecology ,Agroforestry ,010604 marine biology & hydrobiology ,Biodiversity ,Species diversity ,Introduced species ,Biology ,010603 evolutionary biology ,01 natural sciences ,Forest restoration ,Species evenness ,Species richness ,human activities ,Restoration ecology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Tropical rainforest - Abstract
Ecological restoration is increasingly applied in tropical forests to mitigate biodiversity loss and recover ecosystem functions. In restoration ecology, functional richness, rather than species richness, often determines community assembly, and measures of functional diversity provide a mechanistic link between diversity and ecological functioning of restored habitat. Vertebrate animals are important for ecosystem functioning. Here, we examine the functional diversity of small‐to‐medium sized mammals to evaluate the diversity and functional recovery of tropical rainforest. We assess how mammal species diversity and composition and functional diversity and composition, vary along a restoration chronosequence from degraded pasture to “old‐growth” tropical rainforest in the Wet Tropics of Australia. Species richness, diversity, evenness, and abundance did not vary, but total mammal biomass and mean species body mass increased with restoration age. Species composition in restoration forests converged on the composition of old‐growth rainforest and diverged from pasture with increasing restoration age. Functional metrics provided a clearer pattern of recovery than traditional species metrics, with most functional metrics significantly increasing with restoration age when taxonomic‐based metrics did not. Functional evenness and dispersion increased significantly with restoration age, suggesting that niche complementarity enhances species' abundances in restored sites. The change in community composition represented a functional shift from invasive, herbivorous, terrestrial habitat generalists and open environment specialists in pasture and young restoration sites, to predominantly endemic, folivorous, arboreal, and fossorial forest species in older restoration sites. This shift has positive implications for conservation and demonstrates the potential of tropical forest restoration to recover rainforest‐like, diverse faunal communities.
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- 2017
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23. Peculiarities of the production of graphene oxides with controlled properties from industrial coal liquids
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Ricardo Santamaría, Ana M. Pérez-Mas, Laura Fernández-García, Patricia Álvarez, Rosa Menéndez, Marcos Granda, and Clara Blanco
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Anthracene ,Materials science ,Graphene ,General Chemical Engineering ,Organic Chemistry ,Inorganic chemistry ,Oxide ,Energy Engineering and Power Technology ,Tar ,Graphite oxide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Exfoliation joint ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,law ,Graphite ,0210 nano-technology ,Graphene oxide paper - Abstract
The main industrial types of liquid by-products from the metallurgical industry, (impregnation and binder grade tars and anthracene oils) were evaluated as precursors of graphene materials by their graphitization, oxidation and subsequent exfoliation. Impregnation-grade tar and anthracene oils successfully produce graphene oxides with sheet sizes and exfoliation yields which depend on the crystalline size of their parent graphite. Although binder grade tar can also been transformed into graphene materials, the quinoline insoluble particles present in its composition modify the oxidation mechanism of the graphite and the exfoliation of the graphite oxide, decreasing the yield of the graphene oxide prepared from this by-product. These results represent a useful guide for evaluating the conversion of coal liquid residues into a much higher added value product such as graphene.
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- 2017
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24. MnO2/thermally reduced graphene oxide composites for high-voltage asymmetric supercapacitors
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Agata Śliwak, Ewa Miniach, Rosa Menéndez, Adam Moyseowicz, Grażyna Gryglewicz, Marcos Granda, Zoraida González, and Laura Fernández-García
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Supercapacitor ,Materials science ,Graphene ,General Chemical Engineering ,Oxide ,Graphite oxide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Capacitance ,Exfoliation joint ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Electrode ,Composite material ,0210 nano-technology - Abstract
We report on the facile fabrication method of MnO 2 /reduced graphene oxide (MnO 2 /rGO) composites for supercapacitor applications using the hydrothermal approach. The rGO obtained by thermal exfoliation/reduction of graphite oxide with negligible amount of oxygen (0.8 wt%) served as a highly stable, conductive support for porous MnO 2 -nanoneedle-like particles, providing a proper rate capability to the MnO 2 /rGO electrode. The MnO 2 /rGO (3:1) was used as the positive electrode in an asymmetric supercapacitor operating at an outstanding cell voltage of 2.1 V in 1 mol L −1 Na 2 SO 4 . Activated carbon was used as the negative electrode. The calculated energy densities reached remarkable values of 21 and 24 Wh kg −1 (at 100 W kg −1 ) for the asymmetric device charged up to 2.0 and 2.1 V, respectively. The cyclability test followed by post-mortem scanning electron microscopy (SEM) studies of the electrode material revealed excellent electrochemical stability of the MnO 2 /rGO electrode after cycling up to 2.0 V, as reflected by no loss of capacitance after 5000 cycles and preservation of the pristine morphology of the electrode material. The small decrease in capacitance (8%) after 5000 cycles of charge/discharge for the asymmetric system with an operating cell voltage of 2.1 V was the result of the MnO 2 morphology transformation.
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- 2017
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25. Experimental and Statistical Optimization of the Tensile Strength of Carbon Fibers from Pitches with Different Composition
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Noel Díez, Marcos Granda, Ricardo Santamaría, Rosa Menéndez, Patricia Álvarez, and Clara Blanco
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Condensation polymer ,Materials science ,Yield (engineering) ,010405 organic chemistry ,Carbonization ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Factorial experiment ,021001 nanoscience & nanotechnology ,01 natural sciences ,Oxygen ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Degree (temperature) ,chemistry ,Ultimate tensile strength ,Polymer chemistry ,Composition (visual arts) ,Composite material ,0210 nano-technology - Abstract
A factorial analysis was used to maximize the tensile strength of the carbon fibers obtained from pitch by means of a rational selection of variables and precursor properties. The combined influence of the fiber diameter, the soaking time at the optimum stabilization temperature, and the effect of the polycondensation degree of the pitch on the tensile strength of the carbonized fibers was assessed using a factorial design. For the first time, the strong influence of the degree of polycondensation of the parent pitch was evidenced, even though less polycondensed pitches were spun at a higher yield and favored the homogeneous fixation of oxygen during stabilization. Fibers prepared from the most polycondensed pitches exhibited the best values of tensile strength. However, very highly polycondensed pitch compositions may hinder oxygen diffusion and the formation of cross-linked structures during stabilization, leading to a poorer mechanical performance that can be overcome by increasing the stabilization time.
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- 2017
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26. pH robust electrochemical detection of 4-nitrophenol on a reduced graphene oxide modified glassy carbon electrode
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Piotr Wiench, B. Grzyb, Grażyna Gryglewicz, Zoraida González, Rosa Menéndez, and B. Handke
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Graphene ,General Chemical Engineering ,Inorganic chemistry ,Oxide ,Infrared spectroscopy ,02 engineering and technology ,Buffer solution ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Electrochemical gas sensor ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Electrode ,Cyclic voltammetry ,0210 nano-technology - Abstract
A glassy carbon electrode modified with reduced graphene oxide (GCE/rGO) is proposed as a novel electrochemical platform for detecting 4-nitrophenol (4-NP). The examined rGOs were synthesized using a straightforward reduction route under hydrothermal conditions (120, 150 and 180 °C). The rGOs were characterized by X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy and atomic force microscopy. A higher reduction degree was achieved after thermal treatment at 180 °C, as demonstrated by the significant decrease in the oxygen content of the starting GO (from 35.4 to 16.7 at.%) and by the marked restoration of the Csp 2 domains (from 16.1 to 62.4 at.%). The electrochemical activity of GCE/rGOs towards 4-NP was investigated using cyclic voltammetry experiments in a 0.1 M acetate buffer solution (ABS). rGO-180 was selected as the active electrode material of the electrochemical sensor for detecting 4-NP because of the highest measured cathodic reduction current. The results demonstrated an enhancement of the corresponding cathodic currents measured after modification of the GCE and slight changes over the pH range of 4.0–5.0. These results are beneficial for real sample analysis. The sensor worked linearly in the range of 50 to 800 μM and had a detection limit of 42 μM. Interferences of other pollution compounds, such as hydroquinone, catechol and bisphenol A, did not affect the sensing towards 4-NP. The electrode demonstrated good recoveries in real samples and excellent long-term stability (98.98% of the original signal value after 14 days).
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- 2017
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27. Enhanced chemical and electrochemical water oxidation catalytic activity by hybrid carbon nanotube-based iridium catalysts having sulfonate-functionalized NHC ligands
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Rosa Menéndez, Zoraida González, Beatriz Sánchez-Page, Gloria Subías, Ana M. Pérez-Mas, Javier Blasco, M. Victoria Jiménez, Rafael Pereira, Patricia Álvarez, Jesús J. Pérez-Torrente, Jorge Nieto, Matías Blanco, Ministerio de Economía y Competitividad (España), Principado de Asturias, Gobierno de Aragón, Jiménez, M. Victoria, Álvarez Rodríguez, Patricia, Pérez-Torrente, Jesús J., González Arias, Zoraida, Jiménez, M. Victoria [0000-0002-0545-9107], Álvarez Rodríguez, Patricia [0000-0001-9676-0546], Pérez-Torrente, Jesús J. [0000-0002-3327-0918], and González Arias, Zoraida [0000-0001-8932-3671]
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chemistry.chemical_classification ,Water oxidation ,Carbon nanotubes supports ,Ligand ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Electron acceptor ,Electrochemistry ,Iridium ,Catalysis ,chemistry.chemical_compound ,Cerium ,Sulfonate ,chemistry ,Polymer chemistry ,Materials Chemistry ,Water soluble ligands ,Chemical Engineering (miscellaneous) ,Electrical and Electronic Engineering ,N-heterocyclic carbenes (NHC) ,Hybrid material ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) - Abstract
This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Energy Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see [insert ACS Articles on Request author-directed link to Published Work, see https://doi.org/10.1021/acsaem.9b00137, The hybrid materials resulting from the covalent attachment of iridium NHC complexes, bearing 3-methyl-imidazol-2-ylidene and 3-(propyl-3-sulfonate)-imidazol-2-ylidene ligands to carbon nanotubes through ester functions, efficiently catalyzed water oxidation under chemical and electrochemical conditions. The hybrid catalyst featuring an NHC ligand with a propyl-sulfonate wingtip has shown an improved catalytic performance compared to that of the unfunctionalized material with TOF50 numbers up to 1140 h–1 using ammonium cerium(IV) nitrate (CAN) as electron acceptor at [CAN]/[Ir] ratios higher than 2000. The positive effect of the presence of a polar sulfonate group in water oxidation has been also observed in related molecular catalysts with compound [Ir(cod){MeIm(CH2)3SO3}] being more active than [IrCl(cod){MeIm(CH2)3OH}]. The hybrid catalysts were less active than the molecular catalysts although their productivity has been improved by allowing successive additions of CAN or at least three recycling experiments. The electrochemical water oxidation by CNT-based hybrid materials resulted much more efficient. The positive influence of a water-soluble sulfonate wingtip in the hybrid catalysts has been also identified allowing with TOF values close to 22 000 h–1 at 1.4 V. The local structure around iridium atoms in the heterogeneous catalysts has been determined by means of EXAFS applied before and after water oxidation reactions. The first coordination shell is similar in both fresh and postcatalytic catalysts but a slightly increase in the oxidation state of iridium atoms is observed what can be correlated to the peaks shifts in the XPS spectra for the oxidized materials., Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO/FEDER, Projects CTQ2013-42532-P and CTQ2016-75884-P), Diputación General de Aragón (DGA/FSE E42_17R), and Principado de Asturias (FEDER: IDI/2018/000121) are gratefully acknowledged.
- Published
- 2019
28. Multifunctional Silicone Rubber Nanocomposites by Controlling the Structure and Morphology of Graphene Material
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Miguel A. López-Manchado, R. Sanchez-Hidalgo, Clara Blanco, Raquel Verdejo, Rosa Menéndez, Consejo Superior de Investigaciones Científicas (España), and Ministerio de Economía y Competitividad (España)
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Materials science ,Polymers and Plastics ,Mechanical properties ,engineering.material ,mechanical properties ,Silicone rubber ,Elastomer ,law.invention ,Nanocomposites ,lcsh:QD241-441 ,chemistry.chemical_compound ,Thermal conductivity ,lcsh:Organic chemistry ,transport properties ,law ,Specific surface area ,Filler (materials) ,nanocomposites ,Composite material ,chemistry.chemical_classification ,Nanocomposite ,silicone rubber ,Graphene ,graphene ,General Chemistry ,Polymer ,chemistry ,Transport properties ,engineering - Abstract
Multifunctional elastomer nanocomposites have been applied in several high-tech fields. The design of materials with tailored properties capable of tuning their performance is a topical challenge. Here, we demonstrate that it is possible to modulate the mechanical and transport properties of silicone rubber nanocomposites by controlling the structure, chemical composition and morphology of the graphene material. Intrinsic graphene properties, such as remaining oxygen groups, specific surface area, and aspect ratio, among others, have a profound effect on the final properties of the nanocomposite. Thus, the thermal conductivity benefits from larger filler size and high aromatic restoration. Whereas mechanical properties and electrical conductivity require a proper balance between filler/polymer matrix interaction and a partial aromatic restoration., This research was funded by MINECO, grant number MAT2016-81138-R. R.S. thanks to MINECO for the Predoctoral grant BES-2014-070802, We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)
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- 2019
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29. Outstanding electrochemical performance of a graphene-modified graphite felt for vanadium redox flow battery application
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Rosa Menéndez, Clara Blanco, Marcos Granda, Juan Ramon Morante, Zoraida González, Cristina Flox, Ricardo Santamaría, Ministerio de Economía y Competitividad (España), Principado de Asturias, and Generalitat de Catalunya
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Energy Engineering and Power Technology ,Vanadium ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Redox ,law.invention ,Graphite felt ,law ,Graphite ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Renewable Energy, Sustainability and the Environment ,Graphene ,Electrophoretic deposition ,Redox flow battery ,021001 nanoscience & nanotechnology ,Flow battery ,0104 chemical sciences ,Dielectric spectroscopy ,Energy efficiency ,chemistry ,Chemical engineering ,Cyclic voltammetry ,0210 nano-technology - Abstract
The development of more efficient electrode materials is essential to obtain vanadium redox flow batteries (VRFBs) with enhanced energy densities and to make these electrochemical energy storage devices more competitive. A graphene-modified graphite felt synthesized from a raw graphite felt and a graphene oxide water suspension by means of electrophoretic deposition (EPD) is investigated as a suitable electrode material in the positive side of a VRFB cell by means of cyclic voltammetry, impedance spectroscopy and charge/discharge experiments. The remarkably enhanced performance of the resultant hybrid material, in terms of electrochemical activity and kinetic reversibility towards the VO2+/VO2+, and mainly the markedly high energy efficiency of the VRFB cell (c.a. 95.8% at 25 mA cm−2) can be ascribed to the exceptional morphological and chemical characteristics of this tailored material. The 3D-architecture consisting of fibers interconnected by graphene-like sheets positively contributes to the proper development of the vanadium redox reactions and so represents a significant advance in the design of effective electrode materials., The authors thank MINECO (projects MAT2013-48107-C3-1-R, INNPACTO IPT-2011- 1690-920000 and NANO-EN-ESTO MAT2010-2015), Principado de Asturias (Fondo Europeo de Desarrollo Regional: GRUPIN 14-118) and the European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalunya 2007-2013) for their financial support.
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- 2017
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30. Evaluation of sulfur isotopic enrichment of urine metabolites for the differentiation of healthy and prostate cancer mice after the administration of 34S labelled yeast
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Juan Manuel Marchante-Gayón, José Ignacio García Alonso, Rosa Menéndez, Juan Carlos Mayo Barallo, Fernando Moreno Sanz, Oscar Galilea San Blas, and Pilar Herrero Espílez
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education.field_of_study ,Chromatography ,Chemistry ,010401 analytical chemistry ,Population ,Reversed-phase chromatography ,Urine ,Isotopes of sulfur ,Isotope dilution ,Mass spectrometry ,01 natural sciences ,Biochemistry ,High-performance liquid chromatography ,0104 chemical sciences ,Inorganic Chemistry ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Molecular Medicine ,education ,Inductively coupled plasma mass spectrometry - Abstract
Sulfur isotopic enrichment of urine metabolites in healthy and prostate cancer mice using 34S enriched yeast and High Performance Liquid Chromatography coupled to Multicollector Inductively Coupled Plasma Mass Spectrometry (HPLC-MC-ICP-MS) has been evaluated. A 30 weeks experiment (since the eleventh to the fortieth week of life) was carried out collecting the urine of three healthy mice and three transgenic mice with prostate cancer during 24h after a single oral administration of a 34S enriched yeast slurry. The isotopic enrichment of different sulphur metabolites was monitored by coupling a C18 reverse phase HPLC column with a multicollector ICP-MS using a membrane desolvating system. Quantification of sulfur in the chromatographic peaks was carried out by post-column isotope dilution using a 33S enriched spike. Differences between the 34S enrichment in the urine metabolites of healthy and prostate cancer mice were found from the beginning of the disease. Both populations could be differentiated using a principal component analysis (PCA). Finally, 7 unknown mice were correctly classified in each population using a linear discriminant analysis.
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- 2017
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31. Do natural enemies really make a difference? Field scale impacts of parasitoid wasps and hoverfly larvae on cereal aphid populations
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Mark Ramsden, Felix L. Wäckers, Simon R. Leather, and Rosa Menéndez
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0106 biological sciences ,Integrated pest management ,Aphid ,biology ,business.industry ,Ecology ,fungi ,Pest control ,food and beverages ,Forestry ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Predation ,Parasitoid ,010602 entomology ,Agronomy ,Insect Science ,Hoverfly ,PEST analysis ,business ,Aphidiinae ,Agronomy and Crop Science - Abstract
Naturally occurring predators and parasitoids are known to reduce the abundance of pest invertebrates in arable crops, yet current treatment thresholds do not account for such a contribution to pest management. In the present study, we provide evidence for the presence of natural enemies correlating with a subsequent reduction in pest population growth. The abundance of cereal aphid pests and two key aphidophagous natural enemies, parasitoid wasps (Aphidiinae) and hoverfly larvae (Syrphinae), was assessed at field boundaries and interiors in southeast England. The highest rate of aphid population growth was associated with locations where no natural enemies were found. The presence of either Aphidiinae wasps or predatory Syrphinae larvae was associated with a reduction in the rate of aphid population growth, irrespective of location within the field, and overall aphid population growth was negatively correlated with increasing natural enemy abundance. The results of the present study indicate that natural enemies contribute significantly to pest control, and provide further evidence supporting the use of management strategies for promoting natural enemies in agro-ecosystems. Aphid predators and parasitoids make an important contribution to aphid pest control within cereal fields, and thresholds for insecticide application should account for this to avoid unnecessary treatments.
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- 2016
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32. Enhancing energy density of carbon-based supercapacitors using Prussian Blue modified positive electrodes
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Zoraida González, Rosa Menéndez, Clara Blanco, Patricia Díaz, Ricardo Santamaría, and Marcos Granda
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Supercapacitor ,Prussian blue ,Materials science ,General Chemical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,Redox ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Standard electrode potential ,Electrode ,Electrochemistry ,medicine ,0210 nano-technology ,Carbon ,Activated carbon ,medicine.drug - Abstract
The modification of MWCNTs with Prussian Blue (PB) represents a significant improvement of the energy density values of asymmetric carbon based supercapacitors (CBSCs) in neutral media (KCl). The development of the faradaic processes associated with the presence of PB on the positive electrode increases not only the capacitance but also the operational voltage of these devices (up to 1.4 V) due to the high electrode potentials at which the Prussian Blue/Berlin Green (PB/BG) redox reactions occur. Accordingly, in asymmetric CBSCs assembled using an activated carbon as negative electrode and MWCNTs as the positive one, suitable modification of MWCNTs with PB increases the energy density of the device fivefold (from 1.46 to 7.68 W h kg −1 ). The resultant system becomes an asymmetric hybrid device in which the energy is stored due to the double layer formation in the negative electrode and the development of the PB faradaic processes in the positive electrode, which acts as a battery.
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- 2016
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33. Measuring the success of reforestation for restoring biodiversity and ecosystem functioning
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Rosa Menéndez, Helen T. Murphy, Mia A. Derhé, and Geoff B. Monteith
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0106 biological sciences ,Ecology ,Agroforestry ,010604 marine biology & hydrobiology ,Biodiversity ,Species diversity ,15. Life on land ,Biology ,010603 evolutionary biology ,01 natural sciences ,Forest restoration ,Abundance (ecology) ,Species evenness ,Ecosystem diversity ,Species richness ,Restoration ecology - Abstract
Summary 1.Effective assessment of the success of ecological restoration projects is critical in justifying the use of restoration in natural resource management as well as improving best practice. One of the main goals of ecological restoration is the recovery of ecosystem function, yet most researchers assume that increasing species and or functional diversity equates with restoration of ecosystem function, rather than empirically demonstrating these mechanistic relationships. 2.In this study we assess how dung beetle species diversity, community composition, functional diversity and ecological functions vary along a restoration chronosequence and compare restored areas with reference (rainforest) and degraded (pasture) systems. We also directly investigate the dung beetle diversity – ecosystem functioning relationship in the context of ecological rainforest restoration by testing the predictive power of traditional taxonomic indices and functional diversity metrics for functionality. 3.Species richness, abundance, biomass and functional richness all increased with restoration age, with the oldest restoration sites being most similar to rainforest; whereas functional evenness and functional divergence decreased with restoration age. Community composition in the restored areas was clearly progressing towards the rainforest sites and deviating from the pasture sites with increasing restoration age. 4.Secondary seed dispersal rates increased with restoration age, but there was only a weak positive relationship between dung removal and soil excavation and restoration age. Biodiversity metrics explained 47–74% of the variation in functions mediated by dung beetles; however, functional trait-based indices provided greater explanatory power of functionality than traditional species-based metrics. 5.Synthesis and applications. Our results provide empirical evidence on the potential of tropical forest restoration to mitigate biodiversity losses, recovering not only faunal species diversity, but also functional diversity and ecosystem functions in a relatively short period of time. We also demonstrate that functional trait-based metrics are better predictors of functionality than traditional species-based metrics but that the relationship between restoration age, diversity and ecosystem functioning is not straightforward and depends on the functions, traits and metrics used.
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- 2016
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34. The effects of land use change on native dung beetle diversity and function in Australia's Wet Tropics
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Rosa Menéndez, Tania M. Kenyon, Geoff B. Monteith, and Margaret M. Mayfield
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0106 biological sciences ,Ecology ,biology ,Agroforestry ,010604 marine biology & hydrobiology ,Biodiversity ,Tropics ,Rainforest ,15. Life on land ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Species evenness ,Scarabaeinae ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Tropical rainforest ,Dung beetle - Abstract
The impacts of land use change on biodiversity and ecosystem functions are variable, particularly in fragmented tropical rainforest systems with high diversity. Dung beetles (Scarabaeinae) are an ideal group to investigate the relationship between land use change, diversity and ecosystem function as they are easily surveyed, sensitive to habitat modification and perform many ecosystem functions. Although this relationship has been investigated for dung beetles in some tropical regions, there has been no study assessing how native dung beetles in Australia's tropical rainforests respond to deforestation, and what the corresponding consequences are for dung removal (a key ecosystem function fulfilled by dung beetles). In this study we investigated the relationship between dung beetle community attributes (determined through trapping) and function (using dung removal experiments that allowed different dung beetle functional groups to access the dung) in rainforest and cleared pasture in a tropical landscape in Australia's Wet Tropics. Species richness, abundance and biomass were higher in rainforest compared to adjacent pasture, and species composition between these land use types differed significantly. However, average body size and evenness in body size were higher in pasture than in rainforest. Dung removal was higher in rainforest than in pasture when both functional groups or tunnelers only could access the dung. Increased dung removal in the rainforest was explained by higher biodiversity and dominance of a small number of species with distinct body sizes, as dung removal was best predicted by the evenness in body size of the community. Our findings suggest that functional traits (including body size and dung relocation behaviour) present in a dung beetle community are key drivers of dung removal. Overall, our results show that deforestation has reduced native dung beetle diversity in Australian tropical landscapes, which negatively impacts on the capacity for dung removal by dung beetles in this region.
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- 2016
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35. C4F8 plasma treatment as an effective route for improving rate performance of natural/synthetic graphite anodes in lithium ion batteries
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Yu Jin Han, Jyongsik Jang, Koji Nakabayashi, Choonghyeon Lee, Rosa Menéndez, Young Deok Seo, Jin Miyawaki, Ricardo Santamaría, and Seong Ho Yoon
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Materials science ,Graphite anode ,chemistry.chemical_element ,Plasma treatment ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Chemical engineering ,chemistry ,Fluorine ,Organic chemistry ,General Materials Science ,Lithium ,Graphite ,0210 nano-technology ,Plasma processing ,Faraday efficiency - Abstract
Carbon-fluorine (C m F n ) groups were selectively introduced on the surface of natural and synthetic graphites through plasma-fluorination using C 4 F 8 vacuum plasma treatment. The type of carbon-fluorine bondings on the plasma-fluorinated graphite surface were selectively controlled by adjusting plasma processing time from 10 to 20 min. Systematic surface analyses revealed that the fluorine amount on the surface of plasma-fluorinated graphite was determined by the type of intrinsic structure and degree of graphitization of graphite. The electronegative semi-ionic carbon-fluorine groups on the graphite surface reduced the resistance related to lithium ion migration and charge transfer, leading to highest discharge capacity of 387 mA h/g at 1st cycle and discharge capacity of 293 mA h/g at high 10 C rate without deteriorating the 1st cycle Coulombic efficiency. This novel vacuum plasma treatment of introducing highly electronegative C m F n species on graphite can illuminate a new route of preparing superior lithium ion battery anode.
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- 2016
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36. Graphene anchored palladium complex as efficient and recyclable catalyst in the Heck cross-coupling reaction
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Clara Blanco, Laura Fernández-García, Ricardo Santamaría, Matías Blanco, Patricia Álvarez, Rosa Menéndez, and Marcos Granda
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inorganic chemicals ,Process Chemistry and Technology ,Aryl ,Butyl acrylate ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,Coupling reaction ,0104 chemical sciences ,Styrene ,chemistry.chemical_compound ,chemistry ,Heck reaction ,Polymer chemistry ,Organic chemistry ,Surface modification ,Physical and Theoretical Chemistry ,0210 nano-technology ,Palladium - Abstract
The immobilization of organometallic molecular catalysts on carbon nanomaterials requires an appropriate synthesis and functionalization methodology to yield active heterogeneous systems. In this work, molecular palladium complexes were synthesized on the aromatic network of a graphenic material employing diazonium chemistry and additional simple modifications to generate a bidentate coordination site for the palladium atoms. The presence of 0.2–0.25 nm palladium(II) species on the surface of the graphenic layers was confirmed by XPS and HRTEM. The modified palladium-graphene hybrid was found to be active as catalyst in the cross-coupling Heck reaction between styrene or n -butyl acrylate with a wide range of aryl bromides substituted with different electron-acceptor and electron-withdrawing groups. The coupled products were obtained in good to excellent yields, at initial TOFs as high as 1.1 s −1 . In addition, the catalyst showed excellent cyclability and air stability, and was reused over 8 cycles without any loss of activity.
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- 2016
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37. Optimization of a carbon-based hybrid energy storage device with cerium (III) sulfate as redox electrolyte
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Ricardo Santamaría, Marcos Granda, Clara Blanco, Rosa Menéndez, Patricia Díaz, and Zoraida González
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Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Redox ,Reference electrode ,0104 chemical sciences ,chemistry.chemical_compound ,Cerium ,chemistry ,Electrode ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Cerium(III) sulfate ,0210 nano-technology ,Carbon - Abstract
The electrochemical performance of a carbon-based hybrid energy storage system, with Ce 2 (SO 4 ) 3 /H 2 SO 4 as inorganic redox electrolyte, was enhanced by optimizing several parameters of the device. A mass balance of the two electrodes forming the system together with the selection of a suitable activated carbon as negative electrode allowed the cell voltage to be increased up to 1.9 V. In addition, the use of a cation-exchange membrane significantly enhanced the electrochemical performance of the system by minimizing secondary reactions of cerium ions on the negative electrode. The optimized device reached energy and power density values up to ∼20 W h kg −1 and 524 W kg −1 respectively. Moreover, the system showed a good long-term electrochemical performance over 20,000 cycles.
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- 2016
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38. Cokes of different origin as precursors of graphene oxide
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Rosa Menéndez, Uriel Sierra, Clara Blanco, Marcos Granda, Ricardo Santamaría, and Patricia Álvarez
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Materials science ,General Chemical Engineering ,Inorganic chemistry ,Oxide ,Energy Engineering and Power Technology ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,complex mixtures ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,law ,Graphite ,Chemical composition ,Graphene oxide paper ,Graphene ,Organic Chemistry ,technology, industry, and agriculture ,Coke ,021001 nanoscience & nanotechnology ,respiratory tract diseases ,0104 chemical sciences ,Fuel Technology ,Petrochemical ,chemistry ,0210 nano-technology - Abstract
This study demonstrates that pregraphitic materials (cokes) of different origin (petroleum and coal derivatives) can be used as precursors of graphene oxides. Two carbochemical cokes and a petrochemical one were oxidized and the resultant coke oxides exfoliated by ultrasounds to yield the corresponding graphene oxide materials. These were characterized in terms of the lateral size of the sheets, morphology and chemical composition. The new generation of graphene oxides prepared with coke exhibits similar characteristics to those traditionally obtained from graphite. It is also established that as larger the crystalline structure of the coke is, the higher the graphene oxide yields and the larger the size of the sheets.
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- 2016
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39. Reduced graphene oxide membranes in ocular regenerative medicine
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Álvaro Fernández-Vega, Natalia Vázquez, Mairobi Persinal, Zoraida González, María R. Sierra, Iriana Zambrano-Andazol, Ronald M Sanchez-Avila, Jesus Merayo-Lloves, Rosa Menéndez, Teresa Sanchez, Alvaro Meana, Clara Blanco, Manuel Chacon, and Principado de Asturias
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Materials science ,Biocompatibility ,Biocompatible Materials ,Bioengineering ,02 engineering and technology ,Pharmacology ,Eye ,Regenerative Medicine ,010402 general chemistry ,medicine.disease_cause ,01 natural sciences ,Regenerative medicine ,Biomaterials ,Tissue engineering ,medicine ,GO biocompatibility ,Humans ,Biological membrane ,021001 nanoscience & nanotechnology ,Ophthalmology [Tissue Engineering] ,In vitro ,0104 chemical sciences ,Membrane ,ocular Regenerative Medicine ,Mechanics of Materials ,Tissue Engineering: Ophthalmology ,Graphite ,0210 nano-technology ,Wound healing ,Reduced graphene oxide membrane ,Genotoxicity - Abstract
Biological membranes are currently used in Ophthalmology in order to treat different ocular disorders. These membranes have different properties such as cellular biocompatibility and promoting wound healing. Moreover, intrinsic antimicrobial properties could also be desirable because it would allow their use reducing the risk of infections. Graphene and its derivatives are promising biomaterials that already proved their bactericidal effect. However, their clinical use is limited due to the controversial results regarding their toxicity. In this work, we have developed and characterized a reduced graphene oxide membrane (rGOM) for its use in ocular Regenerative Medicine, and studied its in vitro and in vivo biocompatibility and genotoxicity with different types of human ocular cells. We proved that rGOM allowed the growth of different ocular cells without inducing in vitro or in vivo cytotoxicity or genotoxicity in the short-term. These results indicate that rGOM may be a promising candidate in Regenerative Medicine for the treatment of different ocular pathologies., This work was supported by Consejería de Economía y Empleo del Principado de Asturias: [grant number: IDE/2014/000737 and IDE/2015/000889].
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- 2020
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40. Microwave heating as a novel route for obtaining carbon precursors from anthracene oil
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M.F. Drăgoescu, Valerica Slăvescu, Sorin Mircea Axinte, Georgeta Predeanu, Zoraida González, Beatriz Acevedo, Patricia Álvarez, Sonia Melendi-Espina, A. Fiti, J.J. Fernández, Grażyna Gryglewicz, Marcos Granda, Rosa Menéndez, European Commission, González Arias, Zoraida [0000-0001-8932-3671], Álvarez Rodríguez, Patricia [0000-0001-9676-0546], Granda Ferreira, Marcos [0000-0001-7479-0445], González Arias, Zoraida, Álvarez Rodríguez, Patricia, and Granda Ferreira, Marcos
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Thermogravimetric analysis ,Carbon precursor ,Materials science ,Softening point ,020209 energy ,General Chemical Engineering ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,chemistry.chemical_compound ,020401 chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,0204 chemical engineering ,Anthracene ,Conventional heating ,Oxidative polymerization ,Energy consumption ,Hildebrand solubility parameter ,Fuel Technology ,Anthracene oil-based pitches ,chemistry ,Polymerization ,Microwave heating ,Cavity magnetron ,Carbon ,Microwave - Abstract
This work describes a novel route for the preparation of pitches by oxidative polymerization of an industrial anthracene oil (AO) in a microwave semi-pilot equipment consisting in a multi-mode applicator having a 2.45 GHz magnetron with variable microwave power. The experimental five variables of microwave heating of AO air-blowing range between 320 and 380 °C (temperature), 0.2–3.9 °C min−1 (heating rate), 1.5–5 h (soaking time), 16–20.5% (air/AO ratio) and 200–1500 g (initial weight). Their effect on the overall microwave air-blowing process is evaluated by means of a statistical analysis. A detailed characterization of the pitches has been carried out in terms of ultimate analysis, softening point, solubility parameters (toluene insolubles (TI) and quinoline insolubles (QI)) and thermogravimetric analysis. The experiments were also carried out by using conventional heating for comparative purposes. The detailed study of the electric energy consumption of the overall microwave treatment allows estimating a significant electric energy saving of about 20% when compared to conventional heating thus representing an excellent result in the production of carbon precursors., The research leading to these results has received funding from the European Union's Research Fund for Coal and Steel (RFCS) research programme under grant agreement RFCR-CT-2015-00006.
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- 2019
41. Electrochemical reduction of Graphene Oxide on biomedical grade CoCr alloy
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Olga Caballero-Calero, Zoraida González, María Lorenza Escudero, A. García-Argumánez, Rosa Menéndez, María Cristina García-Alonso, Irene Llorente, and Ministerio de Economía y Competitividad (España)
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Materials science ,Alloy ,Oxide ,General Physics and Astronomy ,Substrate (electronics) ,engineering.material ,law.invention ,symbols.namesake ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,law ,AFMXPS ,Graphene oxide ,Electrochemical reduction ,Graphene ,Surfaces and Interfaces ,General Chemistry ,Chronoamperometry ,Condensed Matter Physics ,Surfaces, Coatings and Films ,chemistry ,Chemical engineering ,Raman spectroscopy ,symbols ,engineering ,Cyclic voltammetry - Abstract
In the present work, the characterization of Electrochemically Reduced Graphene Oxide (ErGO) films on a biomedical grade CoCr alloy has been performed. The direct electrodeposition process was carried out by means of two electrochemical techniques: chronoamperometry and cyclic voltammetry experiments, both taking into account the influence of oxygen in the solution. Characterization of the resulting ErGO films on CoCr alloys was carried out by SEM, AFM, Raman spectroscopy and XPS. Both electrochemical reduction procedures led to the deposition of graphene-based films on the CoCr surfaces after the partial removal of the oxygenated functional groups present in the graphene network of the starting material. The deconvolution of the XPS high-resolution C1s and O1s spectra mainly showed Csp2 bonding and the presence of CO and CO residual groups covering the CoCr surface. Moreover, the ErGO films that were stacked on the CoCr surfaces exhibited non-uniform thickness reaching values corresponding to the presence of 80 layers of the graphene material. In addition, Raman spectroscopy revealed a certain structural disorder in the ErGO films deposited by means of the different electrochemical techniques investigated. This fact was more evident on the film from the chronoamperometric experiments, as the fastest electrochemical reduction rate provided by the application of a high reduction potential (−2.1 Vvs. Ag/AgCl) could induce the development of defects in the resulting film, so the peaks corresponding to the CoCr substrate could be observed., This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness [MAT2015-67750-C3-1-R].
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- 2019
42. Enhanced performance of pyrrolic N-doped reduced graphene oxide-modified glassy carbon electrodes for dopamine sensing
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Zoraida González, Stanisław Gryglewicz, Piotr Wiench, Rosa Menéndez, and Grażyna Gryglewicz
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General Chemical Engineering ,Dopamine ,Inorganic chemistry ,Oxide ,chemistry.chemical_element ,02 engineering and technology ,Glassy carbon ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,Selective detection ,law ,Nitrogen-doped reduced graphene oxide ,Graphene ,Chemistry ,021001 nanoscience & nanotechnology ,Nitrogen ,0104 chemical sciences ,Electrochemical gas sensor ,Electrochemical sensor ,Electrode ,0210 nano-technology ,Selectivity - Abstract
Two different nitrogen-doped reduced graphene oxides (N-rGOs) were used to modify glassy carbon electrodes (GCE/N-rGOs) as electrochemical sensors for the detection of dopamine (DA). For comparison, GCE/rGO was also studied. The N-rGOs were synthesized via hydrothermal treatment of graphene oxide (GO) with the N-dopants amitrole and urea. The resultant graphene materials exhibited distinct types and distributions of nitrogenated functional groups, but they possessed a similar oxygen content, thus avoiding interference from oxygenated groups. Pyridinic nitrogen was introduced into the rGO structure when amitrole was used as the N-dopant, whereas pyrrolic nitrogen was preferentially formed in the reaction with urea. After optimization of several experimental parameters and sensor calibration, the GCE/pyrrolic-N-rGO electrode was found to exhibit superior electrochemical performance compared with the pyridinic-N-rGO one, demonstrating a limit of detection and sensitivity of 335 nM and 3.51 μA μM, respectively. This sensor also showed better selectivity in the presence of interfering agents in the forms of ascorbic and uric acids. A significant improvement of sensor parameters can be explained in terms of the contribution of electrons derived from the pyrrolic structure to the delocalized C sp-conjugated graphene system., This project was supported by the Wrocław Centre of Biotechnology, a program at The Leading National Research Centre (KNOW) for the years 2014–2018, and financed by a statutory activity subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Wrocław University of Science and Technology.
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- 2019
43. Functionally richer communities improve ecosystem functioning: Dung removal and secondary seed dispersal by dung beetles in the Western Palaearctic
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Constantin Ciubuc, Tessa Bargmann, Stefano Ziani, Dirk Rohwedder, Carsten Eichberg, Elham Omidzadeh Ardali, László Somay, Christophe Baltzinger, Marco Heurich, Elena Preda, Iraj Rahimi, Enno Merivee, Märt Kruus, Jörn Buse, Pejman Tahmasebi, Geoffrey Miessen, Amy E. Eycott, Eleanor M. Slade, Joaquín Calatayud, Pierre Jay-Robert, Tanja Milotic, Gergely Boros, Jorge Ari Noriega, Jörg Müller, Jutta Stadler, Rob Rose, Rosa Menéndez, Isabelle Bilger, Anne Must, Maurice Hoffmann, Réka Ádám, Long-Term Ecosystem Research, GHENT UNIVERSITY BEL, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Ecosystèmes forestiers (UR EFNO), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), UNIVERSITY OF TRIER DEU, University of Bergen (UiB), BAVARIAN FOREST NATIONAL PARK GRAFENAU DEU, NATIONAL MUSEUM OF NATURAL SCIENCE (CSIC) MADRID ESP, Lancaster University, HELMHOLTZ CENTRE FOR ENVIRONMENTAL RESEARCH UFZ HALLE SUR SAALE DEU, INSTITUTE OF ECOLOGY AND BOTANY VACRATOT HUN, UNIVERSITY OF KOBLENZ LANDAU DEU, UMEA UNIVERSITY SWE, UNIVERSITY OF BUCHAREST ROM, Université de Montpellier (UM), ESTONIAN UNIVERSITY OF LIFE SCIENCES TARTU EST, SHAHREKORD UNIVERSITY IRN, ZOOLOGICAL RESEARCH MUSEUM ALEXANDER KOENIG BONN DEU, Lancaster Environment Centre, and GEOLAB IMOLA ITA
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0106 biological sciences ,Ecosystem service ,Seed dispersal ,FONCTIONNEMENT DE L'ECOSYSTEME ,Scarabaeidae ,Biology ,010603 evolutionary biology ,01 natural sciences ,Grassland ,Ecosystem services ,03 medical and health sciences ,BOUSIER ,ONGULE DOMESTIQUE ,Ecosystem ,MULTISITE EXPERIMENTS ,REGION PALEARCTIQUE OCCIDENTALE ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Dung beetle ,0303 health sciences ,geography ,geography.geographical_feature_category ,Ecology ,ECOSYSTEM SERVICE ,ECOSYSTEM FUNCTION ,Western Palaearctic ,15. Life on land ,biology.organism_classification ,Latitudinal gradient ,Longitudinal gradient ,Multisite experiments ,LATITUDINAL GRADIENT ,Exclosure ,SCARABAEIDAE ,[SDE]Environmental Sciences ,Ecosystem function ,LONGITUDINAL GRADIENT - Abstract
Aim: In several ecosystems, the diversity of functional species traits has been shown to have a stronger effect on ecosystem functioning than taxonomic diversity alone. However, few studies have explored this idea at a large geographical scale. In a multisite experiment, we unravelled the relationship between ecosystem function and functional completeness of species assemblages using dung beetles as a model group, focusing on dung removal and secondary seed dispersal. Location: Seventeen grassland locations across the Western Palaearctic. Methods: We used a randomized block design with different exclosure types to control the dung and seed removing activities of individual functional groups of the local dung beetle assemblage. We classified dung beetle species according to resource specialization and into functional groups based on dung processing behaviour (dwellers, tunnellers, rollers) and body size (small, large). Additionally, we assessed the role of other soil macro-invertebrates. By sampling the dung beetle community and measuring the remaining dung and seeds after the experiment, the impact of each functional group was estimated. Results: Dung beetle assemblages differed along a north–south and east–west gradient. Dwellers dominated northernmost sites, whereas at lower latitudes we observed more tunnellers and rollers indicating a functional shift. Resource specialists were more abundant in southern and eastern areas. Overall, functional group diversity enhanced dung removal. More dung (+46.9%) and seeds (+32.1%) were removed in the southern sites and tunnellers and rollers were more effective. At the northernmost sites, where tunnellers were scarce or absent, other soil macro-invertebrates removed the majority of dung. Main conclusions: The conservation of functionally complete dung beetle assemblages is crucial to maintain the ecosystem functions provided by dung beetles. Given the latitudinal variation in functional group diversity, it is reasonable to expect compositional changes due to climate change. These changes could lead to increased dung removal and a higher secondary seed dispersal rate in northern regions., This study is the result of a pan‐European multisite project, financially supported by the ALTER‐Net consortium, Europe's Ecosystem Research Network. The project was cofinanced within their multisiteresearch programme.
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- 2019
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44. Enhancing the hydrogen transfer catalytic activity of hybrid carbon nanotube-based NHC–iridium catalysts by increasing the oxidation degree of the nanosupport
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Rosa Menéndez, Patricia Álvarez, M. Victoria Jiménez, Vera Cuartero, Luis A. Oro, Matías Blanco, Jesús J. Pérez-Torrente, Clara Blanco, Javier Blasco, Ministerio de Economía y Competitividad (España), European Commission, Diputación General de Aragón, Ministerio de Educación, Cultura y Deporte (España), CSIC, Inst Nacl Carbon INCAR, POB 73, Oviedo 33080, Spain, Univ Zaragoza, ISQCH CSIC, Dept Inorgan Chem, E-50009 Zaragoza, Spain, Univ Zaragoza, CSIC, ICMA, Dept Fis Mat Condensada, E-50009 Zaragoza, Spain, and European Synchrotron Radiation Facility (ESRF)
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Hydrogen ,Chemistry ,Inorganic chemistry ,Cyclohexanol ,chemistry.chemical_element ,Cyclohexanone ,02 engineering and technology ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Chemical engineering ,law ,[CHIM]Chemical Sciences ,Surface modification ,Iridium ,0210 nano-technology ,Hybrid material - Abstract
CVD-grown multiwalled carbon nanotubes were purified by applying four different treatments with increasing oxidation severity. The growing severity of the treatment results in progressive oxygen functionalization of the surface along with introduction of an increasing quantity of defects on the carbon nanotube walls. Iridium-N-heterocyclic carbene complexes were covalently anchored to those oxidized surfaces through their surface carboxylic acids via acetyl linkers. The carbon nanotube-based iridium-NHC hybrid materials developed are active in the hydrogen-transfer reduction of cyclohexanone to cyclohexanol with 2-propanol/KOH as hydrogen source but with rather different activity. The catalytic activity of the hybrid catalysts is strongly influenced by the type and amount of oxygenated functionalization resulting from the treatment applied to the support, being the most active and the most oxidized material., The authors thank the Spanish Ministry of Economy and Competitiveness (MINECO/FEDER) (Projects Consolider Ingenio 2010 CSD2009-00050 and CTQ2013-42532-P) and the Diputación General de Aragón (FSE-E07 and FSE-E69) for their financial support. Dr. P. A. thanks MINECO for a Ramón y Cajal contract. M. B. acknowledges his fellowship from MECD (AP2010-0025).
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- 2016
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45. Enhancement of the rate performance of plasma-treated platelet carbon nanofiber anodes in lithium-ion batteries
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Jin Miyawaki, Jyongsik Jang, Koji Nakabayashi, Yu Jin Han, Choonghyeon Lee, Seong Ho Yoon, Young Deok Seo, Rosa Menéndez, and Ricardo Santamaría
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Materials science ,Carbon nanofiber ,General Chemical Engineering ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Anode ,Secondary ion mass spectrometry ,chemistry ,X-ray photoelectron spectroscopy ,Chemical engineering ,Nanofiber ,Lithium ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Faraday efficiency - Abstract
The rate performances of lithium-ion battery (LIB) anodes using platelet carbon nanofiber (PCNF) and its graphitized version (GPCNF) are enormously enhanced by introducing carbon–fluorine (CmFn) functional groups on the nanofiber surfaces. The CmFn functional groups are selectively introduced through controlled plasma treatment in vacuo with C4F8 gas. Combined X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analyses demonstrate that the CmFn functional groups had mainly semi-ionic C–F bonds, which are introduced only on the surface of PCNF and GPCNF. PCNF treated with the plasma for 60 s (PCNF–F60 s) exhibits the largest discharge capacity of 387 mA h g−1 with increased first-cycle coulombic efficiency and a discharge capacity of 293 mA h g−1 at the 10C rate. These are 1.13- and 1.63-fold higher, respectively, than those of pristine PCNF. The presence of CmFn functional groups on the PCNF and GPCNF surfaces can reduce the resistance of the anode, which is related to lithium-ion migration and charge transfer resistance. The improved migration and reduced resistance result in a marked increase in rate performance at discharge without deterioration of the first-cycle coulombic efficiency.
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- 2016
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46. Complementarity of dung beetle species with different functional behaviours influence dung–soil carbon cycling
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Kate H. Orwin, Paul Webb, and Rosa Menéndez
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0106 biological sciences ,chemistry.chemical_classification ,Biomass (ecology) ,Nutrient cycle ,biology ,Ecology ,Soil Science ,04 agricultural and veterinary sciences ,Soil carbon ,biology.organism_classification ,complex mixtures ,010603 evolutionary biology ,01 natural sciences ,Microbiology ,Mesocosm ,chemistry ,Microbial population biology ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Soil horizon ,Organic matter ,Dung beetle - Abstract
Decomposition of large ungulate herbivore dung and its subsequent incorporation into the soil play key roles in carbon and nutrient cycling and are important for grassland productivity. Dung beetles contribute to the initial breakdown and transport of organic matter from the dung into the soil but how they interact with the microbial community to modify decomposition processes remains poorly understood. Using a mesocosm experiment, we investigated the individual and interactive effect of two dung beetle species with contrasting functional behaviour (dweller species: Agrilinus ater (De Geer 1774) vs. tunneler species: Typhaeus typhoeus (Linneaus 1758)) on dung C cycling (CO2 fluxes and C transfer through the soil profile) and resultant effects on microbial activity and biomass in the soil. Both dung beetle species contributed significantly to dung removal, reducing the C lost through microbial respiration from the whole mesocosm. However, C concentrations measured in leachates from the mesocosm were only significantly higher in the presence of the tunneler species, indicating that tunnelling activity was required to increase C transfer down the soil profile. The combined effect of the two dung beetle species resulted in the highest soil microbial respiration from the soil and in particular in the 2–10 cm depth increment, suggesting positive complementarity effects between species with different functional behaviour. We conclude that the return of C in the form of dung in grasslands, coupled with the activity of a functionally diverse dung beetle assemblage, could result in short term fluctuations in soil microbial activity with important consequences for soil C cycling.
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- 2016
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47. New alternatives to graphite for producing graphene materials
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Clara Blanco, Ricardo Santamaría, Rosa Menéndez, Patricia Álvarez, Marcos Granda, and Uriel Sierra
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Materials science ,Materials preparation ,Graphene ,Nanotechnology ,General Chemistry ,Exfoliation joint ,law.invention ,Economic advantage ,law ,Energy cost ,General Materials Science ,Chemical route ,Graphite ,Graphene oxide paper - Abstract
Graphite (natural or synthetic) is the primary source for graphene materials preparation by the top down technology. The preparation of synthetic graphite requires temperatures above 2500 °C which represents a high energy cost. Herein we demonstrate that graphene materials can be prepared directly from a pregraphitic material using two of the most widely used procedures (chemical route and solvent exfoliation). In this way, extreme graphitization temperatures are avoided. In general terms, the graphene materials obtained from the pregraphitic materials exhibit similar characteristics to those obtained from graphite. These findings represent a breakthrough in the preparation of graphene materials by the top-down technology with clear environmental and economic advantages.
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- 2015
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48. Selection of aphid prey by a generalist predator: do prey chemical defences matter?
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Rosa Menéndez, Chris M. Nesbit, Andrew Wilby, and Michael R. Roberts
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Larva ,Aphid ,Ecology ,biology ,Brevicoryne brassicae ,Insect Science ,Foraging ,Myzus persicae ,biology.organism_classification ,Predator ,Chrysoperla carnea ,Predation - Abstract
1. For predators, prey selection should maximise nutrition and minimise fitness costs. In the present study, it was investigated whether a generalist predator [Chrysoperla carnea (Stephens) lacewing larvae] rejected harmful, chemically-defended prey [Brevicoryne brassicae (Linnaeus) aphids] when non-defended prey [Myzus persicae (Sulzer) aphids] were available. 2. It was tested: (i) whether consuming different prey species affects predator mortality; (ii) whether naive predators reject chemically-defended prey while foraging when non-defended prey are available; (iii) whether the relative abundance of each prey affects the predator's prey choice; and (iv) whether predators learn to avoid consuming chemically-defended prey after exposure to both prey species. 3. Consumption of B. brassicae yielded greater C. carnea mortality than M. persicae consumption, but naive C. carnea did not reject B. brassicae in favour of M. persicae during foraging. When presented at unequal abundances, naive predators generally consumed each aphid species according to their initial relative abundance, although, predation of non-defended prey was less than expected when defended prey were initially more abundant, indicating a high consumption of B. brassicae impeded M. persicae consumption. With experience, C. carnea maintained predation of both aphid species but consumed more M. persicae than B. brassicae, indicating a change in behaviour. 4. Although prey choice by C. carnea may change with experience of available prey, prey chemical defences do not appear to influence prey choice by naive predators. This inability to avoid harmful prey could facilitate wider, indirect interactions. Myzus persicae may benefit where high consumption of B. brassicae hinders predators in the short term, and in the long term, increases predator mortality.
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- 2015
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49. Surface treatment of polyimide substrates for the transfer and multitransfer of graphene films
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Nuria Campos, David Gomez, Rosa Menéndez, Patricia Álvarez, and Ana M. Pérez-Mas
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Chemical vapour deposition ,Materials science ,General Physics and Astronomy ,Nanotechnology ,02 engineering and technology ,Chemical vapor deposition ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,Electrical resistivity and conductivity ,law ,Graphene transfer ,0103 physical sciences ,Plasma treatment ,Sheet resistance ,Graphene oxide paper ,010302 applied physics ,Graphene ,Graphene foam ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Wet chemical treatment ,Chemical engineering ,chemistry ,Tetrafluoromethane ,Graphene synthesis ,0210 nano-technology ,Polyimide - Abstract
This work explores the use of polyimide substrates for the development of flexible graphene-based devices. Single layer graphene was synthesized by chemical vapour deposition and transferred to untreated and treated polyimide substrates. Of the four different surface treatments, the tetrafluoromethane/oxygen plasma and, especially, hydrochloric acid bath treatments showed the best performance, as they reduced the resistivity of the graphene samples by as much as 46%. At the same time, resistivity was also reduced by as much as 96% due to the increase in the graphene coverage area as a result of repeating the transfer process up to four times. The combination of HCl treatment and transfer iteration led to the samples acquiring a sheet resistance of 800 Ω/sq. To the best of our knowledge, this is the lowest value ever reported in the literature for graphene samples on conventional flexible polymeric substrates and, in particular, in polyimide, the most widely used material for flexible applications. This result represents a major contribution to the development of graphene-based flexible devices., The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 600849 (INSIDDE Project). Support from Spanish MICINN (TECNIGRAF (IPT-2011-0951-390000) and Ramon y Cajal Program of P. Alvarez) and FICYT (fellowship of A. Perez-Mas) is also acknowledged.
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- 2015
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50. High-intensity ultrasonication as a way to prepare graphene/amorphous iron oxyhydroxide hybrid electrode with high capacity in lithium battery
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Ricardo Alcántara, Ekaterina Zhecheva, Francisco Nacimiento, José R. González, Rosa Menéndez, Radostina Stoyanova, and José L. Tirado
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Materials science ,Acoustics and Ultrasonics ,Graphene ,Organic Chemistry ,Graphene foam ,Inorganic chemistry ,Iron oxide ,Nanoparticle ,Lithium battery ,law.invention ,Amorphous solid ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,law ,Chemical Engineering (miscellaneous) ,Environmental Chemistry ,Radiology, Nuclear Medicine and imaging ,Hybrid material ,Graphene oxide paper - Abstract
The preparation of graphene/iron oxyhydroxide hybrid electrode material with very homogeneous distribution and close contact of graphene and amorphous iron oxyhydroxide nanoparticles has been achieved by using high-intensity ultrasonication. Due to the negative charge of the graphene surface, iron ions are attracted toward the surface of dispersed graphene, according to the zeta potential measurements. The anchoring of the FeO(OH) particles to the graphene layers has been revealed by using mainly TEM, XPS and EPR. TEM observations show that the size of the iron oxide particles is about 4 nm. The ultrasonication treatment is the key parameter to achieve small particle size in these graphene/iron oxyhydroxide hybrid materials. The electrochemical behavior of composite graphene/amorphous iron oxyhydroxide prepared by using high-intensity ultrasonication is outstanding in terms of gravimetric capacity and cycling stability, particularly when metallic foam is used as both the substrate and current collector. The XRD-amorphous character of iron oxyhydroxide in the hybrid electrode material and the small particle size contribute to achieve the improved electrochemical performance.
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- 2015
- Full Text
- View/download PDF
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