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The 15 January 2022 submarine eruption at Hunga volcano was the most explosive volcanic eruption in 140 years. It involved exceptional magma and seawater interaction throughout the entire submarine caldera collapse. The submarine volcanic jet breached the sea surface and formed a subaerial eruptive plume that transported volcanic ash, gas, sea salts and seawater up to ~ 57 km, reaching into the mesosphere. We document high concentrations of sea salts in tephra (volcanic ash) collected shortly after deposition. We also discuss the potential climatic consequences of large-scale injection of salts into the upper atmosphere during submarine eruptions. Sodium chloride in these volcanic plumes can reach extreme concentrations, and dehalogenation of chlorides and bromides poses the risk of long-term atmospheric and weather impact. Salt content in rapidly collected tephra samples may also be used as a proxy to estimate the water:magma ratio during eruption, with implications for quantification of fragmentation efficiency in submarine breaching events. The balance between salt loading into the atmosphere versus deposition in ash aggregates is a key factor in understanding the atmospheric and climatic consequences of submarine eruptions.

Textural parameters such as density, porosity, pore connectivity, permeability, and vesicle size distributions of vesiculated and dense pyroclasts from the 9.4-ka eruption of Kilian Volcano, were quantified to constrain conduit and eruptive processes. The eruption generated a sequence of five vertical explosions of decreasing intensity, producing pyroclastic density currents and tephra fallout. The initial and final phases of the eruption correspond to the fragmentation of a degassed plug, as suggested by the increase of dense juvenile clasts (bimodal density distributions) as well as non-juvenile clasts, resulting from the reaming of a crater. In contrast, the intermediate eruptive phases were the results of more open-conduit conditions (unimodal density distributions, decreases in dense juvenile pyroclasts, and non-juvenile clasts). Vesicles within the pyroclasts are almost fully connected; however, there are a wide range of permeabilities, especially for the dense juvenile clasts. Textural analysis of the juvenile clasts reveals two vesiculation events: (1) an early nucleation event at low decompression rates during slow magma ascent producing a population of large bubbles (>1 mm) and (2) a syn-explosive nucleation event, followed by growth and coalescence of small bubbles controlled by high decompression rates immediately prior to or during explosive fragmentation. The similarities in pyroclast textures between the Kilian explosions and those at Soufrière Hills Volcano on Montserrat, in 1997, imply that eruptive processes in the two systems were rather similar and probably common to vulcanian eruptions in general.

Objective: To study the levels of procalcitonin (PCT) in various inflammatory states seen in an internal medicine department and to evaluate the possible discriminative role of PCT in differentiating bacterial infection from other inflammatory processes. Methods: PCT, C reactive protein (CRP), and white blood cell count (WBC) were measured in patients admitted to the department for fever or biological inflammatory syndrome, or both. The serum of 173 consecutive patients was analysed according to the aetiological diagnosis. The patients were divided into two groups: group I (n=60) with documented bacterial or fungal infection; group II (n=113) with abacterial inflammatory disease. Results: PCT levels were >0.5 ng/ml in 39/60 (65%) patients in group I. In group II, three patients with a viral infection had slightly increased PCT levels (0.7, 0.8, and 1.1 ng/ml) as did two others, one with crystal arthritis and the other with vasculitis (0.7 ng/ml in both cases). All other patients in group II had PCT levels <0.5 ng/ml. In this study a value of PCT >0.5 ng/ml was taken as the marker of bacterial infection (sensitivity 65%, specificity 96%). PCT values were more discriminative than WBC and CRP in distinguishing a bacterial infection from another inflammatory process. Conclusion: PCT levels only rose significantly during bacterial infections. In this study PCT levels >1.2 ng/ml were always evidence of bacterial infection and the cue for starting antibiotic treatment.

We previously reported that RGTA, a synthetic heparan sulfate mimetic, induces almost complete closure of craniotomy defects one month after surgery in adult rats. RGTA-treated wounds showed features suggesting unusual cell and matrix interactions reminiscent of developmental events. As healing success or failure is determined shortly after wounding, we examined early events in RGTA-treated wounds. Collagen plasters soaked in a solution of RGTA11 (1.5 Microg per piece) or saline (control) were implanted in rat craniotomy defects. Seven control and seven treated rats were killed daily from days 1 to 7 after surgery. The lesions and adjacent tissues were sampled and processed for morphometry. A layer of type III collagen along the dura mater (DM) thickened up to day 5 in RGTA-treated wounds (p < 0.05 vs day 1), but became thinner in control wounds. Alkaline phosphatase-positive osteoprogenitor cells were detected on day 1 in this layer. Their number increased, and they migrated toward the mid-sagittal sinus and to connective tissue adjacent to the sinus, where they aggregated and differentiated into osteoblasts, forming bone nodules on day 6. These features were not seen in control wounds. Angiogenesis was significantly enhanced in RGTA-treated wounds, especially near the sinus. In vitro, bovine bone endothelial (BBE) cell proliferation was inhibited by RGTA11 in a concentration-dependent manner. In contrast, RGTA11 strongly enhanced the effect of fibroblast growth factor-2 on BBE cell proliferation. These results show that RGTA11, possibly by interacting with heparin-binding growth factors, elicits vascular reactions accompanying the recruitment of a large pool of committed osteoprogenitors from the DM. The DM and the sinus appear to be important centers of organization for craniotomy defect healing. RGTA probably creates an environment that starts a program of directing healing towards bone formation and defect closure.

Textural parameters such as density, porosity, poreconnectivity, permeability, and vesicle size distributions ofvesiculated and dense pyroclasts from the 9.4-ka eruption ofKilianVolcano, were quantified to constrain conduit and eruptiveprocesses. The eruption generated a sequence of five verticalexplosions of decreasing intensity, producing pyroclasticdensity currents and tephra fallout. The initial and final phasesof the eruption correspond to the fragmentation of a degassedplug, as suggested by the increase of dense juvenile clasts(bimodal density distributions) as well as non-juvenile clasts,resulting from the reaming of a crater. In contrast, the intermediateeruptive phases were the results ofmore open-conduitconditions (unimodal density distributions, decreases in densejuvenile pyroclasts, and non-juvenile clasts). Vesicles withinthe pyroclasts are almost fully connected; however, there are awide range of permeabilities, especially for the dense juvenileclasts. Textural analysis of the juvenile clasts reveals two vesiculationevents: (1) an early nucleation event at lowdecompression rates during slow magma ascent producing apopulation of large bubbles (>1 mm) and (2) a syn-explosivenucleation event, followed by growth and coalescence ofsmall bubbles controlled by high decompression rates immediatelyprior to or during explosive fragmentation. The similaritiesin pyroclast textures between the Kilian explosions andthose at Soufrière Hills Volcano on Montserrat, in 1997, implythat eruptive processes in the two systems were rather similarand probably common to vulcanian eruptions in general.

Matrix-based therapy restoring the cell microenvironment is a new approach in regenerative medicine successfully treating human chronic pathologies by using a heparan sulfate mimetic (ReGeneraTing agents [RGTA]). Periodontitis are inflammatory diseases destroying the tooth-supporting tissues with no satisfactory therapy. We studied in vivo RGTA ability to fully restore the tooth-supporting tissues. After periodontitis induction, hamsters were treated with RGTA (1.5 mg kg −1 w −1 ) or saline. Bone loss was evaluated and immunohistochemical labeling of molecules expressed during cementum development was performed. RGTA treatment restored alveolar bone and the attachment apparatus where fibers were inserted in acellular decorin-negative cementum. RGTA treatment increased the epithelial rests of Malassez, previously depleted by periodontitis. Bone morphogenetic protein (BMP) expressions were compartmentalized: BMP-3 was strongly expressed by epithelial rests of Malassez; BMP-7 was expressed by cells lying on the cementum and BMP-2 by osteoprogenitors around bone formation sites but not at the root-bone interface. Cells near the cementum and bone expressed the ALK2 receptor. This is the first evidence that reconstructing the extracellular matrix scaffold with a heparan sulfate mimetic regenerated the root interface despite the persistence of the bacteria responsible for the disease The improved cellular microenvironment led to the sequential recruitment of cell populations involved in attachment apparatus regeneration.

Two pure collagen materials were prepared from acidic collagen solutions at 5 and 40 mg/mL. Benefits of collagen concentration on bone repair were evaluated in vitro with human calvaria cells and in vivo in a rat cranial defect. Both materials exhibited specific structures, 5 mg/mL was soft with an open porous network of fibrils; 40 mg/mL was stiffer with a plugged surface and bundles of collagen fibrils. Osteoblasts seeded on 5 mg/mL formed an epithelioid layer with ultrastructural characteristics of mature osteoblasts and induced mineralization. Numerous osteoblasts migrated inside 5 mg/mL, triggering reorganization of their actin cytoskeleton, whereas on 40 mg/mL osteoblasts remained in a resting state. In rat calvaria defects, both materials induced active bone formation. Dual-energy X-ray absorption bone area measures after 4 weeks averaged 84.0% with 5 mg/mL, 88.4% with 40 mg/mL, and 36.7% in the controls ( p  < 0.05). Tartrate-resistant acid phosphatase-positive giant cells releasing amounts of metalloproteinase-2 progressively degraded the implants at 76.5% with 5 mg/mL and 38.2% with 40 mg/mL ( p  < 0.05), whereas alkaline phosphatase-positive osteoprogenitors invaded collagen remnant. Hence, the dense structure of collagen materials allowed cell invasion and raise their mechanical behavior without addition of chemical cross-linkers. Collagen concentration can be tuned to form 3D matrices for in vitro investigations or to fit degradation rate to different bone repair purposes.

RGTA ® , a new family of dextran-derived healing agents, promotes the repair of various tissues, including bone. In this study, we examined whether a dose of RGTA lower than in our previous studies could still modify the healing pattern in craniotomy defects. In 24 rats, two defects (3 mm diameter) were drilled on either side of the calvaria sagittal suture. The right defect was filled with a piece of collagen soaked with RGTA in phosphate-buffered saline (PBS; 4 μg/ml), and the left one with collagen soaked in PBS only. After 7, 14 and 21 days, the calvaria were removed and processed for histometry. On day 7, in contrast with the control defects, the treated sites were inflammation-free and centripetal bone plates had started to grow. By day 14, the bone filling was significantly enhanced in the treated defects (+ 290%, p < 0.05), and isolated bone nodules had formed within the fibrous connective tissue (= fibrous hammock) joining the defect edges. The hammock had already differentiated by day 7 in all the RGTA-treated defects, and it was significantly thicker on days 14 (+ 190%, p < 0.05) and 21 (+ 139%, p < 0.05). The colonization of the hammock by mast cells was increased in the treated sites (+ 320%, p < 0.05 on day 21). On day 7, most of the bony edges of the treated defects had been resorbed by osteoclasts, while the process only started in the controls. These data indicate that a low dose of RGTA modified the cascade of events occurring at the initial stages of repair, so that the tissular maturation of the treated defects was more rapid. In fact the use of RGTA in the wounds provoked a shift from a fibrous repair as seen in the controls, to a bone reconstruction favoring defect closure.

This article was submitted without an abstract, please refer to the full-text PDF file.

The objective of European climate policy is to deliver emissions reductions associated with European economic activity. A carbon price signal created from the European Emissions Trading Scheme (ETS) is an important component of the policy mix required to deliver these reductions.