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Hydrogenation reactions are a major route of electron and proton flow on Earth. Interfacing geology and organic chemistry, hydrogenations occupy pivotal points in the Earth’s global geochemical cycles. Some examples of hydrogenation reactions on Earth today include the production and consumption of methane in both abiotic and biotic reactions, the reduction of protons in hydrothermal settings, and the biological synthesis and degradation of fatty acids. Hydrogenation reactions were likely important for prebiotic chemistry on the early Earth, and today serve as one of the fundamental reaction classes that enable cellular life to construct biomolecules. An understanding and awareness of hydrogenation reactions is helpful for comprehending the larger web of molecular and material inter-conversions on our planet. In this brief review we detail some important hydrogenation and dehydrogenation reactions as they relate to geology, biology, industry, and atmospheric chemistry. Such reactions have implications ranging from the suite of reactions on early Earth to industrial applications like the production of hydrocarbon fuel.

Nelle aree rurali e montane ‘interne', la riflessione sull'accessibilità implica un cambio di prospettiva rispetto ai contesti più propriamente urbani. Migliorare l'accessibilità di questi territori significa agire su più fronti, non solo potenziando l'offerta di mobilità ma anche agendo sul capitale territoriale locale, (ri)portando servizi, conoscenza e forme di interazione. La Strategia Nazionale per le Aree Interne (snai) muove in questa direzione, promuovendo un approccio place-based fondato da un lato sulla dotazione delle precondizioni strutturali per lo sviluppo territoriale (ivi compresa l'accessibilità), dall'altro sullo sviluppo locale. A partire dal caso studio della Valle Arroscia, analizzata nell'ambito del progetto di ricerca espon urruc e scelta come area progetto della snai in Liguria, il contributo esplora i temi e le sfide peculiari per l'accessibilità nelle aree interne e riflette sulle future prospettive di sviluppo.

Strontium (Sr) is a trace element taken with nutrition and found in bone in close connection to native hydroxyapatite. Sr is involved in a dual mechanism of coupling the stimulation of bone formation with the inhibition of bone resorption, as reported in the literature. Interest in studying Sr has increased in the last decades due to the development of strontium ranelate (SrRan), an orally active agent acting as an anti-osteoporosis drug. However, the use of SrRan was subjected to some limitations starting from 2014 due to its negative side effects on the cardiac safety of patients. In this scenario, an interesting perspective for the administration of Sr is the introduction of Sr ions in biomaterials for bone tissue engineering (BTE) applications. This strategy has attracted attention thanks to its positive effects on bone formation, alongside the reduction of osteoclast activity, proven by in vitro and in vivo studies. The purpose of this review is to go through the classes of biomaterials most commonly used in BTE and functionalized with Sr, i.e., calcium phosphate ceramics, bioactive glasses, metal-based materials, and polymers. The works discussed in this review were selected as representative for each type of the above-mentioned categories, and the biological evaluation in vitro and/or in vivo was the main criterion for selection. The encouraging results collected from the in vitro and in vivo biological evaluations are outlined to highlight the potential applications of materials’ functionalization with Sr as an osteopromoting dopant in BTE.

The treatment of osteoporotic fractures is a severe clinical issue, especially in cases where low support is provided, e.g., pelvis. New treatments aim to stimulate bone formation in compromised scenarios by using multifunctional biomaterials combined with biofabrication techniques to produce 3D structures (scaffolds) that can support bone formation. Bone’s extracellular matrix (ECM) is mainly composed of type I collagen, making this material highly desirable in bone tissue engineering applications, and its bioactivity can be improved by incorporating specific biomolecules. In this work, type I collagen membranes were produced by electrospinning showing a fibre diameter below 200 nm. An optimized one-step strategy allowed to simultaneously crosslink the electrospun membranes and bind ICOS-Fc, a biomolecule able to reversibly inhibit osteoclast activity. The post-treatment did not alter the ECM-like nanostructure of the meshes and the physicochemical properties of collagen. UV-Vis and TGA analyses confirmed both crosslinking and grafting of ICOS-Fc onto the collagen fibres. The preservation of the biological activity of grafted ICOS-Fc was evidenced by the ability to affect the migratory activity of ICOSL-positive cells. The combination of ICOS-Fc with electrospun collagen represents a promising strategy to design multifunctional devices able to boost bone regeneration in osteoporotic fractures.

Abioticmethane(CH4)generationundersubductionzoneconditionshasbeenexperimentallyinvestigatedthroughaqueousreductionofpureC-bearingmaterials(e.g.carbonatemineralsandorganicmatter).However,quantitativeassessmentsofCH4productionintheseexperiments,aswellasthepotentialeffectsofothercomponentssuchasSiO2onthereductionprocesses,havenotyetbeenwellestablished.Here,weperformedexperimentstoquantitativelyevaluatethetime-resolvedCa-carbonateaqueousreductionintoCH4atP=1and2GPaandT=550◦CintheCaO+COH,CaO+SiO2+COH,andCaO+SiO2+MgO+COHsystems,employingcalcite+water±quartz±serpentine(syntheticchlorine(Cl)-bearingchrysotileandnaturalFe−Al-bearingantigorite)asstartingmaterials.Redoxconditionsoftheexperimentswerebufferedbyiron−wüstite(IW)usingadoublecapsulesetting,correspondingtooxygenfugacity(fO2)values(expressedaslogunitsrelativetothefayalite–magnetite–quartzbuffer,FMQ)intheinnercapsuleofFMQ≈−5.5at1GPaandFMQ≈−6.0at2GPa.Thesolidproductsaremainlycomposedofportlandite±larnite±wollastonite±brucite,whileCa-carbonateand/orsilicatereactantscommonlyoccurasrelicts.QuadrupolemassspectrometricanalysisshowsthatCH4andH2OarethemajorCOHmolecularspeciesinthefluidproducts,withmolarratiosbetweenCH4andstartingcalciterepresentingthereactionprogressrangingfrom∼0.13to∼1.00.Comparisonsofexperimentalrunproductswiththermodynamicallypredictedphaseassemblages,togetherwithtime-seriesexperiments,indicatethatthereductionprocessesareprimarilycontrolledbyreactionkinetics.At1GPaand550◦C,rateconstantsof4.0×10−6s−1,7.4×10−6s−1,and2.6×10−6s−1wereretrievedforreactionsstartingwithcalcite+quartz+water,calcite+syntheticCl-bearingchrysotile+water,andcalcite+naturalFe−Al-bearingantigorite+water,respectively,significantlyhigherthantheconstantof0.8×10−6s−1forthesilicate-absentreaction.Besides,anincreaseinpressurescanalsoenhancethereductionefficiencyofCa-carbonatesuntilreachingequilibriumwiththefluids.Ourdataprovideexperimentalevidenceforkinetics-controlledCa-carbonateaqueousreductionintoCH4insubductionzones,indicatingthatsilicateinvolvementand/orpressureincreasecanacceleratethereactionratesthroughshort-livedfluid–rockinteractions,whichmayhaveimportantimplicationsfordeepCmobility.

Rural and peripheral areas, however, defined, suffer from accessibility and mobility problems that challenge their liveability and potential for development. To cope with these challenges, it is ne...

Simon de Hesdin cites his translations of several classical Latin texts, but is only known to us through his translation and extensive commentary of the first books of Valerius Maximus’ Factorum dictorumque memorabilium libri, with its dedication to Charles V, based in part on the commentary by Dionigi da Borgo Sansepolcro. Some years later Nicolas de Gonesse completed the translation and commentary, citing Boccaccio and Petrarch, considered to be the fathers of Italian Humanism. A widely held view holds that Simon de Hesdin is emblematic of mediaeval culture, whereas Nicolas de Gonesse is considered to display the marks of a nascent Humanism originating in Italy. Evidence is provided that shows that Simon de Hesdin shares the same points of view and very similar methods, and that these originate not in Italy but in northern France, some found in Vincent de Beauvais, and others in lesser known sources. Such for instance is the Laus Pisonis, an extremely rare text of remarkable literary quality: Simon de Hesdin drew it from a source similar to the Florilegium Gallicum. The text is not cited by Vincent de Beauvais in France, nor is it referred to by either Petrarch or Boccaccio. A number of scholars in Northern France began to explore and recognize the value of old and rare texts such as the Laus Pisonis, also translating them: a kind of Humanism before Humanism, which suggests that we need to re-consider some over-rigid historiographical models.

Ocean sediments consist mainly of calcium carbonate and organic matter (phytoplankton debris). Once subducted, some carbon is removed from the slab and returns to the atmosphere as CO2in arc magmas. Its isotopic signature is thought to reflect the bulk fraction of inorganic (carbonate) and organic (graphitic) carbon in the sedimentary source. Here we challenge this assumption by experimentally investigating model sediments composed of13C-CaCO3 + 12C-graphite interacting with water at pressure, temperature and redox conditions of an average slab–mantle interface beneath arcs. We show that oxidative dissolution of graphite is the main process controlling the production of CO2, and its isotopic composition reflects the CO2/CaCO3rather than the bulk graphite/CaCO3(i.e., organic/inorganic carbon) fraction. We provide a mathematical model to relate the arc CO2isotopic signature with the fluid–rock ratios and the redox state in force in its subarc source.

It has been recently proposed that high-pressure genesis of abiotic hydrocarbon can lead to strain localization in subducted carbonate rocks1. However, the mechanical effects of the migration of these hydrocarbon-bearing fluids on the infiltrated rocks still need to be constrained.In this study, we investigate omphacitite (i.e. omphacite-rich rock) adjacent to an high-pressure methane source from the Western Italian Alps (Italy) using a multiscale and analytical approach including petrographic, microstructural, X-ray compositional mapping and electron backscatter diffraction analyses (EBSD). In the field, omphacitite bands are 1-5 metres thick and tens of metres long and are adjacent to carbonate rocks affected by high-pressure reduction and methane production.Hand specimens and thin sections display a brecciated structure, with omphacitite fragments ranging in size from a few microns to several centimetres, surrounded by a matrix of jadeite, omphacite, grossular, titanite, and graphite. X-ray compositional maps and cathodoluminescence images highlight oscillatory zoning and skeletal (jackstraw) textures in jadeite, omphacite and garnet in the matrix, suggesting a fast matrix precipitation under plausible disequilibrium conditions. CH4 and H2 are found in fluid inclusions in the jadeite grains. This feature suggests a potential link between the genesis of CH4 in the adjacent carbonate rocks and the brecciation event.EBSD analysis was performed on omphacitite clasts close to their borders, where omphacite grain size varies between a few microns and a maximum of 100 microns. Those omphacite grains display no crystallographic preferred orientation, abundant low angle boundaries and low (< 5°) internal lattice distortion. We interpret these textures as formed by pervasive and diffuse micro-fracturing related to the brecciation occurring at high pore fluid pressure, reaching sub-lithostatic values. This study suggests that at high-pressure conditions in subduction zones, the genesis and migration of hydrocarbon-bearing fluids can trigger fracturing in adjacent lithotypes.1Giuntoli, F., Vitale Brovarone, A. & Menegon, L. Feedback between high-pressure genesis of abiotic methane and strain localization in subducted carbonate rocks. Sci. Rep. 10, 9848 (2020).This work is part of project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 864045).

Bone homeostasis is the equilibrium between organic and inorganic components of the extracellular matrix (ECM) and cells. Alteration of this balance has consequences on bone mass and architecture, resulting in conditions such as osteoporosis (OP). Given ECM protein mutual regulation and their effects on bone structure and mineralization, further insight into their expression is crucial to understanding bone biology under normal and pathological conditions. This study focused on Type I Collagen, which is mainly responsible for structural properties and mineralization of bone, and selected proteins implicated in matrix composition, mineral deposition, and cell-matrix interaction such as Decorin, Osteocalcin, Osteopontin, Bone Sialoprotein 2, Osteonectin and Transforming Growth Factor beta. We developed a novel multidisciplinary approach in order to assess bone matrix in healthy and OP conditions more comprehensively by exploiting the Fourier Transform Infrared Imaging (FTIRI) technique combined with histomorphometry, Sirius Red staining, immunohistochemistry, and Western Blotting. This innovatory procedure allowed for the analysis of superimposed tissue sections and revealed that the alterations in OP bone tissue architecture were associated with warped Type I Collagen structure and deposition but not with changes in the total protein amount. The detected changes in the expression and/or cooperative or antagonist role of Decorin, Osteocalcin, Osteopontin, and Bone Sialoprotein-2 indicate the deep impact of these NCPs on collagen features of OP bone. Overall, our strategy may represent a starting point for designing targeted clinical strategies aimed at bone mass preservation and sustain the FTIRI translational capability as upcoming support for traditional diagnostic methods.

International audience; Abstract Ocean sediments consist mainly of calcium carbonate and organic matter (phytoplankton debris). Once subducted, some carbon is removed from the slab and returns to the atmosphere as CO 2 in arc magmas. Its isotopic signature is thought to reflect the bulk fraction of inorganic (carbonate) and organic (graphitic) carbon in the sedimentary source. Here we challenge this assumption by experimentally investigating model sediments composed of 13 C-CaCO 3 + 12 C-graphite interacting with water at pressure, temperature and redox conditions of an average slab–mantle interface beneath arcs. We show that oxidative dissolution of graphite is the main process controlling the production of CO 2 , and its isotopic composition reflects the CO 2 /CaCO 3 rather than the bulk graphite/CaCO 3 (i.e., organic/inorganic carbon) fraction. We provide a mathematical model to relate the arc CO 2 isotopic signature with the fluid–rock ratios and the redox state in force in its subarc source.

Fluid release from subducting oceanic lithosphere is a key process for subduction zone geodynamics, from controlling arc volcanism to seismicity and tectonic exhumation. However, many fundamental details of fluid composition, flow pathways, and reactivity with slab‐forming rocks remain to be thoroughly understood. In this study we investigate a multi‐kilometer‐long, high‐pressure metasomatic system preserved in the lawsonite‐eclogite metamorphic unit of Alpine Corsica, France. The fluid‐mediated process was localized along a major intra‐slab interface, which is the contact between basement and cover unit. Two distinct metasomatic stages are identified and discussed. We show that these two stages resulted from the infiltration of deep fluids that were derived from the same source and had the same slab‐parallel, updip flow direction. By mass balance analysis, we quantify metasomatic mass changes along this fluid pathway and the time‐integrated fluid fluxes responsible for them. In addition, we also assess carbon fluxes associated with these metasomatic events. The magnitude of the estimated fluid fluxes (104–105) indicates that major intra‐slab interfaces such as lithological boundaries acted as fluid channels facilitating episodic pulses of fluid flow. We also show that when fluids are channelized, high time‐integrated fluid fluxes lead to carbon fluxes several orders of magnitude higher than carbon fluxes generated by local dehydration reactions. Given the size and geologic features of the investigated metasomatic system, we propose that it represents the first reported natural analogue of the so‐called high permeability channels predicted by numerical simulations., Key Points Analysis of metasomatic rocks formed along a slab‐scale lithological interface indicates that extremely high fluid fluxes were realizedReactive fluid flow lead to CO2‐rock interactions, which can sequester as much carbon as the amount liberated from decarbonation/dissolutionThe investigated metasomatic system is the first report of a natural analogue of intra‐slab high permeability channel