| 1. |
- Thomas, HS, et al.
(author)
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- 2019
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swepub:Mat__t
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| 2. |
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| 3. |
- Ferrari, A. C., et al.
(author)
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Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems
- 2015
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:11, s. 4598-4810
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Journal article (peer-reviewed)abstract
- We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.
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| 4. |
- Khrizanforov, Mikhail N, et al.
(author)
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Silica-supported silver nanoparticles as an efficient catalyst for aromatic C-H alkylation and fluoroalkylation
- 2018
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In: Dalton Transactions. - : Royal Society of Chemistry. - 1477-9226 .- 1477-9234. ; 47:29, s. 9608-9616
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Journal article (peer-reviewed)abstract
- The efficient catalysis of oxidative alkylation and fluoroalkylation of aromatic C-H bonds is of paramount importance in the pharmaceutical and agrochemical industries, and requires the development of convenient Ag0-based nano-architectures with high catalytic activity and recyclability. We prepared Ag-doped silica nanoparticles (Ag0/+@SiO2) with a specific nano-architecture, where ultra-small sized silver cores are immersed in silica spheres, 40 nm in size. The nano-architecture provides an efficient electrochemical oxidation of Ag+@SiO2 without any external oxidant. In turn, Ag+@SiO2 5 mol% results in 100% conversion of arenes into their alkylated and fluoroalkylated derivatives in a single step at room temperature under nanoheterogeneous electrochemical conditions. Negligible oxidative leaching of silver from Ag0/+@SiO2 is recorded during the catalytic coupling of arenes with acetic, difluoroacetic and trifluoroacetic acids, which enables the good recyclability of the catalytic function of the Ag0/+@SiO2 nanostructure. The catalyst can be easily separated from the reaction mixture and reused a minimum of five times upon electrochemical regeneration. The use of the developed Ag0@SiO2 nano-architecture as a heterogeneous catalyst facilitates aromatic C-H bond substitution by alkyl and fluoroalkyl groups, which are privileged structural motifs in pharmaceuticals and agrochemicals.
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| 5. |
- Fedorenko, Svetlana V., et al.
(author)
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Silica Nanospheres Coated by Ultrasmall Ag0 Nanoparticles for Oxidative Catalytic Application
- 2017
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In: Colloid and Interface Science Communications. - : Elsevier. - 2215-0382. ; 21, s. 1-5
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Journal article (peer-reviewed)abstract
- The present work introduces optimal modifiсation of core-shell composite nanomaterial, where small (2–8 nm) Ag0 nanoparticles are deposited onto large (about 140 nm) silica spheres for application in oxidative catalysis. The size of Ag0 and density of its deposition onto silica spheres was modified by the post treatment of initially deposited Ag0 (about 30 nm) by hydrogen peroxide in specific conditions. The comparison of catalytic effect of the post-treated and initial SN-Ag0 in electrochemical phosphonation of benzo(thia)oxazoles by diethyl phosphite in oxidative conditions revealed the difference between the composite nanoparticles. In particular, the post-treated SNs-Ag0 nanoparticles exhibit efficient catalytic effect in oxidative conditions resulting in facile and green method for synthesis of phosphonated benzooxa(thia)zoles, while no catalytic effect is observed under the use of larger Ag0 nanoparticles deposited onto silica spheres. The use of Ag0-based nanomaterial in oxidative catalysis had been never demonstrated before
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| 6. |
- Durso, M., et al.
(author)
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Biomimetic graphene for enhanced interaction with the external membrane of astrocytes
- 2018
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In: Journal of Materials Chemistry B. - : Royal Society of Chemistry (RSC). - 2050-7518 .- 2050-750X. ; 6:33, s. 5335-5342
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Journal article (peer-reviewed)abstract
- Graphene and graphene substrates display huge potential as material interfaces for devices and biomedical tools targeting the modulation or recovery of brain functionality. However, to be considered reliable neural interfaces, graphene-derived substrates should properly interact with astrocytes, favoring their growth and avoiding adverse gliotic reactions. Indeed, astrocytes are the most abundant cells in the human brain and they have a crucial physiological role to maintain its homeostasis and modulate synaptic transmission. In this work, we describe a new strategy based on the chemical modification of graphene oxide (GO) with a synthetic phospholipid (PL) to improve interaction of GO with brain astroglial cells. The PL moieties were grafted on GO sheets through polymeric brushes obtained by atom-transfer radical-polymerization (ATRP) between acryloyl-modified PL and GO nanosheets modified with a bromide initiator. The adhesion of primary rat cortical astrocytes on GO-PL substrates increased by about three times with respect to that on glass substrates coated with standard adhesion agents (i.e. poly-d-lysine, PDL) as well as with respect to that on non-functionalized GO. Moreover, we show that astrocytes seeded on GO-PL did not display significant gliotic reactivity, indicating that the material interface did not cause a detrimental inflammatory reaction when interacting with astroglial cells. Our results indicate that the reported biomimetic approach could be applied to neural prosthesis to improve cell colonization and avoid glial scar formation in brain implants. Additionally, improved adhesion could be extremely relevant in devices targeting neural cell sensing/modulation of physiological activity.
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| 7. |
- Ortolani, L., et al.
(author)
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Electrical and holographic characterization of gold catalyzed titania-based layers
- 2007
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In: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 27:13-15, s. 4131-4134
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Journal article (peer-reviewed)abstract
- The sensing properties of titanium oxide have been tailored through doping with niobium and dispersion of nanosized Au particles. The microstructural features of the gold-titania composite system were investigated by transmission electron microscopy and the electronic properties of Au nanoparticles were specifically investigated by electron holography. Holography provides quantitative determination of the mean inner potential with the high spatial resolution attained by transmission electron microscopy. Large increase of the mean inner potential has been measured for ultra small Au particles arising from the nano-scale assembling. Electrical tests were performed at low operating temperatures and demonstrated the considerable enhancement of CO sensitivity owing to the extremely high catalytic activity of gold particles. © 2007 Elsevier Ltd. All rights reserved.
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| 8. |
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| 9. |
- Concina, Isabella, et al.
(author)
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One pot synthesis of bi-linker stabilised CdSe quantum dots
- 2010
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In: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 244
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Journal article (peer-reviewed)abstract
- In this study we exploited the classic Murray's synthesis for generating a hydrophilic CdSe quantum dot system in a single step procedure, with the aim of directly obtaining a material responding to the characteristic of polarity required in many end applications. 6-phosphonohexanoic acid was used as both ligand for generating the active monomer during the synthesis of the quantum dots and final stabiliser. Diffraction measurements identified the cubic phase of cadmium selenide. Energy dispersive spectroscopy analysis revealed non-stoichiometric quantum dots, being the Cd/Se ratio 60/40. This feature suggests a configuration in which Cd2+ ions are present on the nanocrystal surface. Diffuse reflectance infrared Fourier transform analysis was applied in order to investigate the structure of the quantum dot system: the results indicate a configuration in which the carboxylic function of 6-phosphonohexanoic acid establishes only a partial interaction with the quantum dot surface, being set in a pseudo-ester configuration. © 2010 IOP Publishing Ltd.
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| 10. |
- Dell'Elce, Simone, et al.
(author)
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3D to 2D reorganization of silver-thiol nanostructures, triggered by solvent vapor annealing
- 2018
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 10:48, s. 23018-23026
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Journal article (peer-reviewed)abstract
- Metal-organic composites are of great interest for a wide range of applications. The control of their structure remains a challenge, one of the problems being a complex interplay of covalent and supramolecular interactions. This paper describes the self-assembly, thermal stability and phase transitions of ordered structures of silver atoms and thiol molecules spanning from the molecular to the mesoscopic scale. Building blocks of molecularly defined clusters formed from 44 silver atoms, each particle coated by a monolayer of 30 thiol ligands, are used as ideal building blocks. By changing solvent and temperature it is possible to tune the self-assembled 3D crystals of pristine nanoparticles or, conversely, 2D layered structures, with alternated stacks of Ag atoms and thiol monolayers. The study investigates morphological, chemical and structural stability of these materials between 25 and 300 °C in situ and ex situ at the nanoscale by combining optical and electronic spectroscopic and scattering techniques, scanning probe microscopies and density-functional theory (DFT) calculations. The proposed wet-chemistry approach is relatively cheap, easy to implement, and scalable, allowing the fabricated materials with tuned properties using the same building blocks.
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| 11. |
- Froguel, Philippe, et al.
(author)
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A genome-wide association study identifies rs2000999 as a strong genetic determinant of circulating haptoglobin levels
- 2012
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7
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Journal article (peer-reviewed)abstract
- Haptoglobin is an acute phase inflammatory marker. Its main function is to bind hemoglobin released from erythrocytes to aid its elimination, and thereby haptoglobin prevents the generation of reactive oxygen species in the blood. Haptoglobin levels have been repeatedly associated with a variety of inflammation-linked infectious and non-infectious diseases, including malaria, tuberculosis, human immunodeficiency virus, hepatitis C, diabetes, carotid atherosclerosis, and acute myocardial infarction. However, a comprehensive genetic assessment of the inter-individual variability of circulating haptoglobin levels has not been conducted so far. We used a genome-wide association study initially conducted in 631 French children followed by a replication in three additional European sample sets and we identified a common single nucleotide polymorphism (SNP), rs2000999 located in the Haptoglobin gene (HP) as a strong genetic predictor of circulating Haptoglobin levels (P overall = 8.1×10 -59), explaining 45.4% of its genetic variability (11.8% of Hp global variance). The functional relevance of rs2000999 was further demonstrated by its specific association with HP mRNA levels (β = 0.23±0.08, P = 0.007). Finally, SNP rs2000999 was associated with decreased total and low-density lipoprotein cholesterol in 8,789 European children (P total cholesterol = 0.002 and P LDL = 0.0008). Given the central position of haptoglobin in many inflammation-related metabolic pathways, the relevance of rs2000999 genotyping when evaluating haptoglobin concentration should be further investigated in order to improve its diagnostic/therapeutic and/or prevention impact. © 2012 Froguel et al.
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| 12. |
- Gazzano, Massimo, et al.
(author)
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A robust, modular approach to produce graphene-MO X multilayer foams as electrodes for Li-ion batteries
- 2019
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 11:12, s. 5265-5273
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Journal article (peer-reviewed)abstract
- Major breakthroughs in batteries would require the development of new composite electrode materials, with a precisely controlled nanoscale architecture. However, composites used for energy storage are typically a disordered bulk mixture of different materials, or simple coatings of one material onto another. We demonstrate here a new technique to create complex hierarchical electrodes made of multilayers of vertically aligned nanowalls of hematite (Fe 2 O 3 ) alternated with horizontal spacers of reduced graphene oxide (RGO), all deposited on a 3D, conductive graphene foam. The RGO nanosheets act as porous spacers, current collectors and protection against delamination of the hematite. The multilayer composite, formed by up to 7 different layers, can be used with no further processing as an anode in Li-ion batteries, with a specific capacity of up to 1175 μA h cm -2 and a capacity retention of 84% after 1000 cycles. Our coating strategy gives improved cyclability and rate capacity compared to conventional bulk materials. Our production method is ideally suited to assemble an arbitrary number of organic-inorganic materials in an arbitrary number of layers.
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| 13. |
- Kovtun, Alessandro, et al.
(author)
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Benchmarking of graphene-based materials: Real commercial products versus ideal graphene
- 2019
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In: 2D Materials. - : IOP Publishing. - 2053-1583. ; 6:2
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Journal article (peer-reviewed)abstract
- There are tens of industrial producers claiming to sell graphene and related materials (GRM), mostly as solid powders. Recently the quality of commercial GRM has been questioned, and procedures for GRM quality control were suggested using Raman Spectroscopy or Atomic Force Microscopy. Such techniques require dissolving the sample in solvents, possibly introducing artefacts. A more pragmatic approach is needed, based on fast measurements and not requiring any assumption on GRM solubility. To this aim, we report here an overview of the properties of commercial GRM produced by selected companies in Europe, USA and Asia. We benchmark: (A) size, (B) exfoliation grade and (C) oxidation grade of each GRM versus the ones of 'ideal' graphene and, most importantly, versus what reported by the producer. In contrast to previous works, we report explicitly the names of the GRM producers and we do not re-dissolve the GRM in solvents, but only use techniques compatible with industrial powder metrology. A general common trend is observed: Products having low defectivity (%sp 2 bonds >95%) feature low surface area (<200 m 2 g -1 ), while highly exfoliated GRM show a lower sp 2 content, demonstrating that it is still challenging to exfoliate GRM at industrial level without adding defects.
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| 14. |
- Muscarella, Robert, et al.
(author)
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The global abundance of tree palms
- 2020
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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 29:9, s. 1495-1514
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Journal article (peer-reviewed)abstract
- AimPalms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change.LocationTropical and subtropical moist forests.Time periodCurrent.Major taxa studiedPalms (Arecaceae).MethodsWe assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure.ResultsOn average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work.ConclusionsTree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.
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| 15. |
- Pierleoni, Davide, et al.
(author)
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Selective Gas Permeation in Graphene Oxide-Polymer Self-Assembled Multilayers
- 2018
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In: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 10:13, s. 11242-11250
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Journal article (peer-reviewed)abstract
- The performance of polymer-based membranes for gas separation is currently limited by the Robeson limit, stating that it is impossible to have high gas permeability and high gas selectivity at the same time. We describe the production of membranes based on the ability of graphene oxide (GO) and poly(ethyleneimine) (PEI) multilayers to overcome such a limit. The PEI chains act as molecular spacers in between the GO sheets, yielding a highly reproducible, periodic multilayered structure with a constant spacing of 3.7 nm, giving a record combination of gas permeability and selectivity. The membranes feature a remarkable gas selectivity (up to 500 for He/CO 2 ), allowing to overcome the Robeson limit. The permeability of these membranes to different gases depends exponentially on the diameter of the gas molecule, with a sieving mechanism never obtained in pure GO membranes, in which a size cutoff and a complex dependence on the chemical nature of the permeant is typically observed. The tunable permeability, the high selectivity, and the possibility to produce coatings on a wide range of polymers represent a new approach to produce gas separation membranes for large-scale applications.
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| 16. |
- Pierleoni, Davide, et al.
(author)
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Structure and sieving mechanism of high selective graphene-based membranes
- 2018
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In: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1981
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Conference paper (peer-reviewed)abstract
- Graphene oxide was used as charge able to confer high selectivity to the final product. A self-assembling technique, namely layer-by-layer has been developed to stratify graphene-based coating on polymeric films; this coating is composed by nanolayers of graphene oxide alternated with polymers, bonded each other by electrostatic forces. Permeability measurement on layered Matrimid®, a commercial polyimide, showed incredibly high selectivity values to small particle mixtures, as O2, CO2, He and H2. Through simple post-treatments the selective performance was also improved, as demonstration of potentiality of the well-ordered bi-dimensional system: improvement on the coating would make this material one of the viable solution for industrial separations, e.g. hydrogen purification in sustainable energy production. A further investigation on similar structures obtained by other strategies shall demonstrate the peculiar mechanism occurring in this material for high selective performance.
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| 17. |
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| 18. |
- Tavares, Julia, et al.
(author)
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Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests
- 2023
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In: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 617:7959, s. 111-117
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Journal article (peer-reviewed)abstract
- Tropical forests face increasing climate risk(1,2), yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, ?(50)) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk(3-5), little is known about how these vary across Earth's largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters ?(50) and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both ?(50) and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM(50 )forests. We propose that this may be associated with a growth-mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon(6,7), with strong implications for the Amazon carbon sink.
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| 19. |
- Xia, Zhenyuan, 1983, et al.
(author)
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Dispersion Stability and Surface Morphology Study of Electrochemically Exfoliated Bilayer Graphene Oxide
- 2019
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In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 123:24, s. 15122-15130
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Journal article (peer-reviewed)abstract
- During the last decade, electrochemical exfoliation of graphite has aroused great interest from both academia and industry for mass production of graphene sheets. Electrochemically exfoliated graphene oxide (EGO) features a much better tunability than chemically EGO, or even than graphene obtained with ultrasonic exfoliation. Chemical and electrical properties of EGO can be modified extensively, thanks to its step-controllable oxidation process, varying the electrolytes and/or the applied potential. It is thus possible, using tunable electrochemical oxidation, to produce low-defect EGO sheets, featuring both good electric conductivity and good dispersibility in common solvents (e.g., acetonitrile or isopropanol). This greatly facilitates its application in several fields, for example, in flexible electronics. In this work, we correlate the dispersion behavior of EGO with its chemical properties using the relative Hansen solubility parameter, zeta potential values, X-ray photoemission spectroscopy, and Raman analysis. A surface morphology study by atomic force microscopy and transmission electron microscopy analyses also reveals that EGO sheets are multiple structures of (partially oxidized) graphene bilayers. Conductive EGO films could be easily prepared by vacuum filtration on different substrates, obtaining electrical conductivity values of up to ∼104 S/m with no need for further reduction procedures.
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