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Hypothesis The treatment of bone fractures still represents a challenging clinical issue when complications due to impaired bone remodelling (i.e. osteoporosis) or infections occur. These clinical needs still require a radical improvement of the existing therapeutic approach through the design of advanced biomaterials combining the ability to promote bone regeneration with anti-fouling/anti-adhesive properties able to minimise unspecific biomolecules adsorption and bacterial adhesion. Strontium-containing mesoporous bioactive glasses (Sr-MBG), able to exert a pro-osteogenic effect by releasing Sr2+ ions, have been successfully functionalised to provide mixed-charge surface groups with low-fouling abilities. Experiments Sr-MBG have been post-synthesis modified by co-grafting hydrolysable short chain silanes containing amino (aminopropylsilanetriol) and carboxylate (carboxyethylsilanetriol) moieties to achieve a zwitterionic zero-charge surface and then characterised in terms of textural-structural properties, bioactivity, cytotoxicity, pro-osteogenic and low-fouling capabilities. Findings After zwitterionization the in vitro bioactivity is maintained, as well as the ability to release Sr2+ ions capable to induce a mineralization process. Irrespective of their size, Sr-MBG particles did not exhibit any cytotoxicity in pre-osteoblastic MC3T3-E1 up to the concentration of 75 ug/mL. Finally, the zwitterionic Sr-MBGs show a significant reduction of serum protein adhesion with respect to pristine ones. These results open promising future expectations in the design of nanosystems combining pro-osteogenic and anti-adhesive properties., Comment: 26 pages, 8 figures

In the Internal Zone of a continental collisional orogen, first-order contractional shear zones accommodate crustal shortening. Structural investigations at different scales, flow kinematics, and finite strain analyses are fundamental tools to determine how deformation is accommodated and partitioned. Spatial temperature vari-ations can be responsible for the dynamic weakening and strain localization in the crust, therefore understanding the thermal conditions of shearing and deformation is critical. We integrate field observations, meso-and microstructural analyses, kinematic vorticity estimations, and finite strain data with a quantitative thermometric analysis by Raman spectroscopy on carbonaceous material along a ductile shear zone: the Barbagia Thrust (BT) in the hinterland-foreland transition zone of the Sardinian Variscan belt. These analyses, performed in two different parts of the shear zone, yield similar finite strain gradients, albeit with an increasing component of simple shear with increasing temperature, highlighting the feedback between temperature and vorticity. Our results best fits with a tectonic scenario with shear heating, where higher magnitude gradients correspond to higher vorticity and finite strain values, which indicate greater shear and heating values. The heating quantified along the BT (~50C) is compared favorably to numerical and mechanical models. We demonstrate how the BT represents a major tectonic boundary separating the internal sector belonging to the metamorphic core of the belt from the external one involved in the orogenic wedge system.

In the present work, a new combination of synthetic and natural biomaterials is proposed for bone tissue engineering (BTE) applications. In order to mimic the inorganic and organic phases of bone extracellular matrix (ECM), a bioactive glass-ceramic deriving from a SiO2–P2O5–CaO–MgO–Na2O–K2O parent glass, acting as a substrate in form of a slice, was surface-functionalised with a type I collagen-based coating. In particular, the collagen was blended with a water soluble polyurethane (PUR), synthesised from poly(ethylene glycol), 1,6-hexamethylene diisocyanate and N-BOC-serinol. The PUR was designed to expose amino groups on the polymeric chain, which can be exploited for the blend stabilisation through crosslinking. The newly synthesised PUR demonstrated to be non-cytotoxic, as assessed by a biological test with MG-63 osteoblast-like cells. The collagen/PUR blend showed good biocompatibility as well. The polymeric coating on the glass-ceramic samples was produced by surface-silanisation, followed by further chemical grafting of the blend, using genipin as a crosslinker. The glass-ceramic surface was characterised at each functionalisation step, demonstrating that the procedure allowed obtaining a covalent link between the blend and the substrate. Finally, biological tests performed using human periosteal derived precursor cells demonstrated that the proposed polymer-coated material was a good substrate for bone cell adhesion and growth, and a good candidate to mimic the composite nature of the bone ECM.

International audience; Serpentinization is the process of hydroxylation of olivine-rich ultramafic rocks to produce minerals such as serpentine, brucite and magnetite. This process is commonly accompanied by Fe oxidation and release of H2, which can be involved in abiotic reaction pathways leading to the genesis of abiotic light hydrocarbons such as methane (CH4). Examples of this phenomenon exist at the seafloor, such as at the serpentinite-hosted Lost City hydrothermal field, and on land in ophiolites at relatively shallow depths. However, the possibility for serpentinization to occur at greater depths, especially in subduction zones, raises new questions on the genesis of abiotic hydrocarbons at convergent margin and its impact on the deep carbon cycle. High-pressure ultramafic bodies exhumed in metamorphic belts can provide insights on the mechanisms of high-pressure serpentinization in subduction zones and on the chemistry of the resulting fluids. This study focuses on the ultramafic Belvidere Mountain complex belonging to the Appalachian belt of northern Vermont, USA. Microstructures show overgrowth of both primary (Mg# 0.91) and metamorphic (Mg# 0.95) olivine by delicate antigorite crystals, pointing to at least one stage of serpentinization at high-temperature conditions and consistent with the high-pressure subduction evolution of the Belvidere Mountain complex. Formation of ubiquitous magnetite and local Fe–Ni alloys testifies to the partial oxidation of Fe2+ into Fe3+ and generation of reduced conditions. Fluid inclusion trails cross-cutting the primary olivine relicts suggest their formation during the antigorite serpentinization event. MicroRaman spectroscopy on the fluid inclusions reveals a CH4-rich gaseous composition, as well as N2, NH3 and H2S. Moreover, the precipitation of daughter minerals such as lizardite and brucite in the fluid inclusions indicate the initial presence of H2O in the fluid. High-pressure serpentinization driven by the infiltration of metasediment-derived aqueous fluids is proposed at the origin of CH4 and other reduced fluid species preserved in the fluid inclusions. This suggests the Belvidere Mountain complex as an example of deep abiotic hydrocarbon genesis related to high-pressure serpentinization in an early Paleozoic subduction zone.

Climate is regulated by the carbonate–silicate cycle in which slab outgassing of C into deep fluids and volcanic degassing of CO into the atmosphere are an important part. However, the mechanisms of C mobility in subduction zones remain largely unresolved. Previous research has focused mainly on investigating the upward transfer of slab-derived carbonic fluids for the forearc mantle metasomatism and partial melting. Furthermore, percolation of CO-bearing fluids parallel to the downgoing plates can potentially drive carbonation of subducted rocks, which influences the global estimates of C fluxes at convergent margins. Nevertheless, the geological conditions and processes leading to the carbonation of subduction-zone lithologies by fluid–rock interactions are still poorly understood. Here, we present new field, petrological, and isotopic results of carbonated serpentinites—high-pressure (HP) ophidolomites and low-pressure (LP) ophimagnesites and listvenites—from the Chinese southwestern Tianshan HP–UHP metamorphic belt. These rocks recorded the carbonation of subduction-zone serpentinites at HP and LP conditions during exhumation, reflecting the multistage transfer and infiltration of carbonic fluids along the plate boundary. The HP ophidolomites are characterized by the growth of carbonates (dolomite, aragonite, and Mg-calcite) at the expense of silicates in the host serpentinites. Integrated Sr–C–O isotopic data and thermodynamic modelling suggest that carbonic fluids (containing a CO concentration of up to 1.9 molal) emanating from carbonate-bearing metamafic rocks (e.g., eclogites) likely contributed to HP carbonation of serpentinites at about 15–25 kbar and 550–600 °C. The close contact of ophidolomites and carbonated metasedimentary rocks in the field as well as their similarities in Sr isotope compositions suggests that the latter could also have acted as the possible C source. Alternatively, both lithologies may have formed by coupled HP carbonation along the lithological interface between serpentinites and metasedimentary rocks. Subsequent fluid–rock interactions at relatively shallow crustal levels resulted in a second stage of serpentinite carbonation to form LP ophimagnesites and listvenites, during which the metasomatic CO-bearing fluids may have originated from metasedimentary rocks. The multistage CO sequestration in subduction-zone serpentinites implies that hydrated ultramafic rocks in subducted slabs are highly effective reactants to capture and store slab-released C over a wide range of P–T conditions, with the potential to substantially control the C distribution between shallow and deep reservoirs and thus modulate C fluxes in subduction zones., This work was financially supported by The National Natural Science Foundation of China (41520104004, 41330210, and 41872067) and The National Basic Research Program of China (2015CB856105). The first author is deeply indebted to an invitation from Stefano Poli and a scholarship from Graduate School of Peking University (2018-02-005) for supporting his PhD study in Italy. We are grateful to Thomas Bader, Ryosuke Oyanagi, José Alberto Padrón-Navarta, and Zhou Tan for helpful discussions. We thank Zhicheng Liu and Yang Wang for their help during fieldwork. We also thank Hongrui Ding, Wennian Han, Xiangtian Jin, Xiaoli Li, Dongdong Ma, Fang Ma, Hong Qin, Zhaofeng Zhang, Hongli Zhu, and Wenping Zhu for their patient assistance during sample analyses. Alberto Vitale Brovarone participation in this research was supported by the French ANR T-ERC grant, and by the Italian Levi Montalcini program by MIUR. The authors wish to acknowledge Esther Schwarzenbach, Melanie Sieber, and an anonymous reviewer for their detailed and constructive comments that substantially helped to improve the manuscript. Wolfgang Bach is greatly appreciated for his editorial handling and helpful suggestions.

After years of research on the ability of glass-ceramics in bone regeneration, this family of biomaterials has shown revolutionary potentials in a couple of emerging applications such as cancer treatment. Although glass-ceramics have not yet reached their actual potential in cancer therapy, the relevant research activity is significantly growing in this field. It has been projected that this idea and the advent of magnetic bioactive glass-ceramics and mesoporous bioactive glasses could result in major future developments in the field of cancer. Undoubtedly, this strategy needs further developments to better answer the critical questions essential for clinical usage. This review aims to address the existing research developments on glass-ceramics for cancer treatment, starting with the current status and moving to future advances. Statement of Significance Although glass-ceramics have not yet reached their potential in cancer therapy, research activity is significantly growing. It has been speculated that this idea and the advent of modern glass-ceramics could result in significant future advances. Undoubtedly, this strategy needs further investigations and many critical questions have to be answered before it can be successfully applied for cancer treatment. This paper reviews the current state-of-the-art, starting with current products and moving onto recent developments in this field. According to our knowledge, there is a lack of a systematic review on the importance and developments of magnetic bioactive glass-ceramics and mesoporous bioactive glasses for cancer treatment, and it is expected that this review will be of interest to those working in this area.

The interaction between ascending carbonic fluids and rocks at shallow depths in orogenic systems plays an important role in carbon flux regulation. In subduction zones, most works have focused on processes related to carbon release from the subducting slab or sequestration via high-pressure (HP) carbonation of mafic or ultramafic lithologies. A significant fraction of the carbonic fluids released by deep metamorphic reactions can also reach orogenic complexes and react with crustal and exhumed metamorphic rocks. However, the amount of fluid-mediated carbonation that may take place at crustal depths in orogenic complexes is still poorly constrained.We report the occurrence of retrograde mafic eclogites and metasomatic marbles in UHP units in the Chinese Tianshan orogenic belt. The mafic eclogites recorded two successive, superimposed metamorphic–metasomatic stages: graphite precipitation along fractures and veins at eclogite facies (Stage#1) and pervasive rock carbonation (i.e., Stage#2: silicate dissolution and carbonate precipitation) at retrograde amphibolite to greenschist facies. This work focuses on Stage#2 carbonation, which consists of the transformation of Stage#1 graphite-bearing eclogites into carbonate + paragonite (± zoisite) + quartz. We present field, microstructural, petrological, and geochemical results of carbonic fluid–rock interactions affecting exhumed mafic eclogites. These results are supported by thermodynamic modeling for low-pressure carbonation of mafic eclogite obtained by means of EQ3/6 and the Deep Earth Water model. Carbon and oxygen isotopic data and thermodynamic modeling suggest an external metasedimentary source for the Stage#2 carbonation. This deep carbon sequestration event can be referred to retrograde, greenschist-facies conditions at about 10 kbar and 450 °C, and redox conditions similar or more oxidized than the quartz–fayalite–magnetite (QFM) buffer. Our findings provide new insights into the reactivity of metastable, exhumed metamafic rocks with ascending carbonic fluids in orogenic systems. We conclude that retrograde, fluid-mediated rock carbonation can significantly impact on carbon fluxes from active collisional belts.

Serpentinization occurs both within the seafloor, when seawater percolates through fractures to alter underlying peridotite, and in subduction zones, when aqueous fluids from the dehydration of the slab are released within the subduction channel. The main difference between these two environments is, therefore, the source of serpentinizing fluid. However, distinguishing between the various types of serpentinites encountered in suture zones is difficult, essentially because of the lack of significant differences in their mineralogy and major and trace element chemistry. Eight samples from Corsica and the Western Alps representing slab serpentinites (i.e., serpentinites embedded within the subducting slab, which are fragments of former abyssal serpentinites) and seven samples from Guatemala and Nicaragua representing mantle wedge serpentinites (i.e., serpentinites that form in situ above the subducting slab, by hydration of the overlying mantle wedge) have been selected to study their Fluid-Mobile Elements, REE concentrations, and boron (B) isotopic signatures. The trace element results do not allow a conclusion about the source of fluid(s), but the B isotopic signatures do permit identification of the different fluid sources responsible for the serpentinization. The δ11B values of slab serpentinites are significantly positive, ranging from +12 to +34‰, in the same range as present-day abyssal serpentinites (+5.5 to +40.5‰), which are altered by seawater. Therefore, these positive signatures indicate serpentinization by seawater-derived fluid. The B isotopic signature acquired during oceanic residency is therefore preserved even after subduction processes subjected the serpentinites to eclogite facies conditions. By contrast, δ11B in samples from the mantle wedge range from −14 to +10‰, supporting the interpretation of interactions with fluids derived from the progressive dehydration of the slab, which releases fluids with slightly positive and negative δ11B. It indicates that mantle wedge serpentinite isotopic signature is acquired via the infiltration of subducted crust-derived metamorphic fluids during the subduction processes. © 2020 Elsevier B.V.

Transit-oriented development (TOD), first coined and mainly applied in the US, has received increasing interest in Europe over the past two decades as a sort of reinterpretation of typical intrinsic European planning principles and values. In the Old continent, it especially focuses on transport and land use integration, extending the approach from the local to the regional framework. This regional shift implies an intergovernmental cooperative approach with vertical and horizontal institutional coordination that constitutes both a strategic value and one of the main barriers to the implementation of TOD. This paper focuses on the role of regional planning for TOD by analysing its benefits, tools and barriers, both theoretically and through two European case studies. The latter, which were conducted in the Netherlands and in Italy, were selected as they belong to two different “planning families”, in order to underscore how and to what extent they apply this multi-level governance approach and overcome institutional barriers to the implementation of TOD. The analysis reveals that, albeit the two planning styles lead to different results, the main issue remains the deep coordination of land use and transport, which is hard to achieve despite dedicated efforts.

International audience; Despite decades of petrological and geochemical studies, the nature and setting of obducted ophiolites remain controversial: the influence of supra-subduction zone environments on pre-existing oceanic lithosphere is yet to assess, and the processes leading to subduction/obduction initiation are still poorly constrained. Our study documents successive influx of slab-derived fluids and progressive strain localization within the upper mantle in a supra-subduction environment during the first few My of the subduction history. We focus on strongly sheared mafic amphibolites intruding peridotites near the mantle–crust transition of the New Caledonia obducted ophiolite and ~ 50 to 100 m above the basal thrust contact of the ophiolite. These m- to hm-long and several m-thick shear bands are interpreted as inherited small-scale intrusions of mafic melts, probably dikes or sills, which were derived from a moderately refractory mantle source refertilized by supra-subduction zone fluids. 40Ar/39Ar age constraints on pargasite at ca. 90 Ma suggest that they could be inherited from the former Pacific west-dipping subduction.Secondary deformation of these mafic intrusions is intimately associated to three major stages of fluid infiltration: (1) the first stage of deformation and metasomatism is marked by syn-kinematic growth of Ca-amphibole (at 700–800 °C and 3–5 kbar) with a distinctive supra-subduction zone signature, and controlled later channelization of aqueous fluids. 40Ar/39Ar dating on magnesio-hornblende indicates that this deformation episode occurred at ca. 55 Ma, coincident with east-dipping subduction initiation; (2) the main metasomatic stage, characterized by the development of a phlogopite-rich matrix wrapping peridotites and amphibolite boudins, points to the percolation of alkali-rich aqueous fluids at still high temperature (650–750 °C); (3) the last, low temperature (< 600 °C) metasomatic stage results in the formation of deformed veinlets containing talc, chlorite and serpentine.

Tethyan ophiolites show an apparent poorly organized association of ultramafic and mafic rocks. By contrast to the complete mantle-crustal sections of Semail-type ophiolite sheets, Tethyan ophiolites are characterized by a smaller amount of mafic rocks (gabbros and basalts), by the absence of any sheeted dyke complex and by the frequent occurrence of oceanic sediments stratigraphically overlying mantle-derived peridotites and associated gabbroic intrusions. Therefore, they are considered as typical remnants of oceanic lithosphere formed in slow- spreading environment or in ocean–continent transition at distal passive margins. In the very first models of formation of the Tethyan ophiolites, in the years 1980, the geodynamical processes leading to mantle unroofing were poorly understood due to the paucity of data and concepts available at that time from the present-day oceans. In particular, at that time, little work had focused on the distribution, origin and significance of mafic rocks with respect to the dominant surrounding ultramafics. Here, we reconsider the geology of some typical metaophiolites from the Western Alps and Corsica, and we show how results from the past decade obtained in the current oceans ask for reassessing the significance of the Tethyan ophiolites in general. Revisited examples include a set of representative metaophiolites from the blueschists units of the Western Alps (Queyras region) and from Alpine Corsica (Golo Valley). Field relationships between the ophiolitic basement and the metasedimentary/metavolcanic oceanic cover are described, outlining a typical character of the Tethyan ophiolite lithological associations. Jurassic marbles and polymictic ophiolite metabreccias are unconformably overlying the mantle-gabbo basement, in a way strictly similar to what is observed in the non-metamorphic Appennine ophiolites or Chenaillet massif. This confirms that very early tectonic juxtaposition of ultramafic and mafic rocks occurred in the oceanic domain before subduction. This juxtaposition resulted from tectonic activity that is now assigned to the development of detachment faults and to the formation of Oceanic Core Complexes (OCCs) at the axis of slow spreading ridges. This fundamental Plate Tectonics process is responsible for the exhu- mation and for the axial denudation of mantle rocks and gabbros at diverging plate boundaries. In addition, field relationships between the discontinuous basaltic formations and the ultramafic–mafic basement indicate that this tectonic stage is followed or not by a volcanic stage. We discuss this issue in the light of available field constraints.

Novel bone glass fibre scaffolds were developed by thermally bonding phosphate glass fibres belonging to the P2O5-CaO-Na2O-SiO2-MgO-K2O-TiO2 system (TiPS2.5 glass). Scaffolds with fibres of 85 or 110µm diameter were fabricated, showing compressive strength in the range of 2–3.5 MPa, comparable to that of the trabecular bone. The effect of different thermal treatments and fibre diameters and length on the final scaffold structure was investigated by means of micro-CT analysis. The change of the sintering time from 30 to 60 min led to a decrease in the scaffold overall porosity from 58 to 21 vol.% for the 85µm fibre scaffold and from 50 to 40 vol.% when increasing the sintering temperature from 490 to 50°C for the 110µm fibre scaffold. The 85µm fibres resulted in an increase of the scaffold overall porosity, increased pore size and lower trabecular thickness; the use of different fibre diameters allowed the fabrication of a scaffold showing a porosity gradient. In order to impart bioactive properties to the scaffold, for the first time in the literature the introduction in these fibre scaffolds of a bioactive phase, a melt-derived bioactive glass (CEL2) powder or spray-dried mesoporous bioactive glass particles (SD-MBG) was investigated. The scaffold bioactivity was assessed through soaking in simulated body fluid. CEL2/glass fibre scaffold did not show promising results due to particle detachment from the fibres during soaking in simulated body fluid. Instead the use of mesoporous bioactive powders showed to be an effective way to impart bioactivity to the scaffold and could be further exploited in the future through the ability of mesoporous particles to act as systems for the controlled release of drugs.

The osseointegration of dental implants and their consequent long-term success is guaranteed by the presence, in the extraction site, of healthy and sufficient alveolar bone. Bone deficiencies may be the result of extraction traumas, periodontal disease and infection. In these cases, placement of titanium implants is contraindicated until a vertical bone augmentation is obtained. This goal is achieved using bone graft materials, which should simulate extracellular matrix (ECM), in order to promote osteoblast proliferation and fill the void, maintaining the space without collapsing until the new bone is formed. In this work, we design, develop and characterize a novel, moldable chitosan-pectin hydrogel reinforced by biphasic calcium phosphate particles with size in the range of 100–300 μm. The polysaccharide nature of the hydrogel mimics the ECM of natural bone, and the ceramic particles promote high osteoblast proliferation, assessed by Scanning Electron Microscopy analysis. Swelling properties allow significant adsorption of water solution (up to 200% of solution content) so that the bone defect space can be filled by the material in an in vivo scenario. The incorporation of ceramic particles makes the material stable at different pH and increases the compressive elastic modulus, toughness and ultimate tensile strength. Furthermore, cell studies with SAOS-2 human osteoblastic cell line show high cell proliferation and adhesion already after 72 h, and the presence of ceramic particles increases the expression of alkaline phosphatase activity after 1 week. These results suggest a great potential of the developed moldable biomaterials for the regeneration of the alveolar bone. Statement of Significance The positive fate of a surgical procedure involving the insertion of a titanium screw still depends on the quality and quantity of alveolar bone which is present in the extraction site. Available materials are basically hard scaffold materials with un-predictable behavior in different condition and difficult shaping properties. In this work we developed a novel pectin-chitosan hydrogel reinforced with ceramic particles. Polysaccharides simulate the extracellular matrix of natural bone and the extensive in vitro cells culture study allows to assess that the incorporation of the ceramic particles promote a pro-osteogenic response. Shape control, easy adaption of the extraction site, predictable behavior in different environment condition, swelling properties and an anti-inflammatory response are the significant characteristics of the developed biomaterial.

Hybrid rocks formed by fluid–rock interactions at high-pressure (HP) metamorphic conditions are active players in the recycling of volatiles in subduction zones. Such rocks include chlorite–talc–amphibole-rich (± carbonate) rocks formed by chemical and mechanical mixing of mafic, ultramafic and sedimentary protoliths. Recent discovery of widespread formation of lawsonite-rich hybrid rocks extends the composition range of these rocks and their significance for volatile transfer to the deep Earth. In this study we quantify the drastic water enrichment across a metasomatic aureole characterized by intense chemical resetting and massive lawsonite precipitation in Alpine Corsica (France). The chemical composition of the metasomatic product, which in many cases approaches the CASH system, favors (i) the precipitation of lawsonite and the unexpected reincorporation of free water at HP conditions, and (ii) the stability of lawsonite at higher temperature and at greater depth compared to the MORB + H 2 O system. We conclude that these hybrid rocks may contribute to transfer water to great depth in subduction, with implications for water cycling to the mantle.

Garnet is a key mineral used to constrain pressure, temperature and age of metamorphic rocks. This contribution reports oxygen isotope measurements in garnet using the SHRIMP-SI ion microprobe. The reproducibility of oxygen isotope analyses on garnet standard UWG2 is ~ 0.3–0.4‰ (2σ) within and across sessions. The correlation between oxygen isotope measurements and the grossular and andradite components in garnet fits a second-degree polynomial with a maximum bias in δ18O of 2.4 and 8.3‰, respectively. This bias is similar to that determined for other large ion microprobes. Analysis of two additional Mn-rich garnet crystals allowed identification of a separate bias caused by the spessartine component, which can reach a maximum of 2.3‰. The standardisation and correction scheme proposed in this study are applied to garnet crystals from two samples from Alpine Corsica in order to link fluid evolution with the pressure–temperature–time path. The samples have experienced a polyphase metamorphic history, which includes Permian high temperature metamorphism, followed by late However, 92-W2 was re-analysed because of the variability observed in the previously published δ18O values (-0.29 and 0.53‰, Kohn and Valley, 1998). The δ18O value found in this study (0.81 ± 0.44‰, 2s, Table 1) agrees within error with the highest value previously published for this garnet. Eocene high pressure–low temperature metamorphism. Permian Ca-poor garnet cores have high δ18O values (9.9 ± 0.6‰ and 11.1 ± 0.5‰ 2σ, in two samples) with respect to garnet mantles (7.2 ± 0.4‰) and rims (5.4 ± 0.5‰ and 2.2 ± 0.4‰). The dramatic decrease in δ18O from Permian garnet cores to Alpine rims in both samples reflects a combination of external fluid influx and change in sample mineralogy. The low δ18O of the garnet rims that formed at eclogite facies conditions indicates that the metasomatic fluid equilibrated with mafic or ultramafic rocks. This study illustrates that fluid-mediated mass transfer during subduction occurred at lithological contacts between felsic and ultramafic rocks.

The mechanical behaviour of implantable scaffolds is of relevant interest in all applications which require load-bearing capability. This study aims at establishing a quantitative relationship between the mechanical properties of glass-ceramic scaffolds for bone repair and the nano/micro-scale properties of their constituent materials. A nanoindentation study is carried out spanning different penetration depth on bulk (pore-free) glass-ceramic samples and on the walls of porous scaffolds. Micro-tomographical investigations allow assessing small-scale porosity of the scaffold walls. A simple homogenization model is used to establish the relationship between the elastic modulus of the bulk material and that of the micro-porous walls of the scaffolds. The elastic modulus of scaffold walls was found to be approximately 50% lower than that of the bulk glass-ceramic. The properties estimated experimentally on the walls of the scaffolds are quantitatively consistent with the analytical predictions provided by the homogenization model and the micro-porosity measured through tomographical analyses.

International audience; High-pressure metamorphic rocks exhumed in mountain belts provide a unique window on deep processes at subduction zones, such as the progressive transformation of blueschist into eclogite, which has important geochemical and geophysical implications, along with information on their exhumation mechanism. We provide a detailed characterization of the field and metamorphic relationships between blueschist- and eclogite-facies terranes of Alpine Corsica (France), where both primary, pre-subduction structures and Alpine high-pressure assemblages are very well preserved. We then compare our data with available observations from the Western Alps. Altogether, these data show systematic metamorphic patterns across the blueschist–eclogite boundary: temperature increases progressively without any gap across the contact, whereas a significant pressure jump (ca. 0.4 GPa) is observed. Lithostratigraphy in the two units suggests that they belong to two different types of oceanic (or transitional) crust, structures of which may have controlled their different mechanisms of decollement, accretion and exhumation. Lastly, the comparison of the exhumed terranes in Alpine belts with structures of modern analogues in present-day oceans, such as large detachment faults and oceanic core-complexes, stresses the importance of inherited extensional structures for subduction, exhumation and orogenic processes.

Over the last 25 years, the philosophy behind an optimal fixation of orthopaedic implants to hard tissues progressively evolved towards “bone-conservative” solutions in order to minimize bone resection/loss and maximize tissue-implant integration. Hence, the researchers׳ attention moved from “traditional” fixation of the prosthesis to host bone by using screws or acrylic cement to new strategies based on physico-chemical bonding and surface modification of the implant. This research work explores the feasibility of a novel bioceramic monoblock acetabular cup for hip joint prosthesis that can be fixed to the patient׳s bone by means of a bone-like trabecular coating able to promote implant osteointegration. Sponge replica method was properly adapted and optimized to produce hemispherical foam-like bioactive glass-ceramic coatings that were joined to Al2O3/ZrO2 composite cups by the interposition of a glass-ceramic interlayer. Morphological analyses by scanning electron microscopy (SEM) and micro-computed tomography revealed the good quality of joining at the different interfaces. Preliminary investigation of the mechanical properties was carried out to evaluate the suitability of the device for biomedical use. In vitro bioactive behaviour was assessed by immersion studies in simulated body fluid and evaluating the apatite formation on the struts of the trabecular coating. The concepts and findings reported in the present work can have a significant impact in the field of implantable devices, suggesting a valuable alternative to currently-applied but often suboptimal techniques for bone-prosthesis fixation.

The influence of using bioactive glass as a sintering aid in the production of tricalcium phosphate (TCP) scaffolds was investigated. The scaffolds were fabricated by sponge replication followed by sintering in a range of temperatures from 1150 to 1300 °C. Morphological investigations by SEM and micro-computed tomography showed that the scaffolds exhibited a three-dimensional trabecular architecture mimicking that of cancellous bone, with high porosity (about 80 vol%) and highly-interconnected macropores with mean pore size of 314 μm. Apart from playing a role in improving the mechanical properties of the scaffolds, glass was shown to enhance the stability of β-TCP by increasing the β → α phase transition temperature.

The punctual analysis of bone Extracellular Matrix (ECM) proteins represents a pivotal point for medical research in bone diseases like osteoporosis. Studies in this field, historically done to appreciate bone biology, were mainly conducted on animal samples and, up to today, only a few studies on protein detection in human bone are present. The challenges in bone ECM protein extraction and quantitation protocols are related to both the separation of proteins from the mineral content (i.e. hydroxyapatite) and the difficulty of avoiding protein denaturation during the extraction processes. The aim of the present work was to define appropriate protocol(s) for bone ECM protein extraction that could be applied to investigate both normal and pathological conditions. We compared and optimised some of the most used protocols present in the literature, modifying the protein precipitation method, the buffer used for resuspension and/or the volume of reagent used. Bradford and BCA assays and Western Blotting were used to evaluate the variations in the total protein recovery and the amount of selected proteins (Type I Collagen, TGF-β, IGF-1, Decorin, Osteopontin, Bone Sialoprotein-2 and Osteocalcin). Collectively, we were capable to draw-up two single-extract protocols with optimal recovery and ideal protein content, that can be used for a detailed analysis of ECM proteins in pathological bone samples. Time-consuming multi-extract procedures, optimised in their precipitation methods, are however crucial for a precise detection of specific proteins, like osteocalcin. As the matter of fact, also the demineralization processes, commonly suggested and performed in several protocols, could hinder an accurate protein detection, thus inherently affecting the study of a pathological bone ECM. This study represents a starting point for the definition of appropriate strategies in the study of bone extracellular matrix proteins involved in the onset and maintenance of bone diseases, as well as a tool for the development of customized scaffolds capable to modulate a proper feedback loop in bone remodelling, altered in case of diseases like osteoporosis.

Bioactive glasses were invented 45 years ago and have been in clinical use since the 1980s in otology, orthopaedics and dentistry. Initially born as bioactive materials to fill bone defects, bioactive glasses expanded their biomedical suitability towards a broad spectrum of tissue engineering and therapeutic applications, and research evolution seems to witness that their potential is far from being fully exploited. Classical applications of bioactive glasses involve bone filling materials and dental implants; however, the fascinating question to be answered in the next few years is: how can bioactive glasses be useful in soft tissue regeneration and to treat diseases, such as tumours, that may affect internal organs? This review paper focuses on research that demonstrates the suitability of bioactive glasses in contact with tissues outside the skeletal system, including muscle and nerve tissue regeneration, treatment of diseases affecting sense organs (eye and ear), embolization of neoplastic tissues, cancer radiotherapy via injectable microspheres, and wound dressing. A prospect for future research is also provided, highlighting the potential associated to targeted therapy via local ion release, angiogenesis stimulation and in situ drug release, as well as the promise of biofabrication for the development of bioactive glass-containing composite constructs for organ regeneration.