A global review of Hf-Nd isotopes: New perspectives on the chicken-and-egg problem of ancient mantle signatures

Acknowledgements We are grateful to T. Morishita and C.J. Garrido for their support during the laborious elaboration of the database and writing of the manuscript. We thank A. Sanfilippo for providing data for the individual MOR segments. Constructive comments and suggestions by M. Bizimis, an anonymous reviewer and the editor C. Chauvel greatly improved the manuscript. Romain Tilhac acknowledges grant FJC2018-036729 funded by MCIN/AEI/10.13039/501100011033 and “ESF, Investing in your future” and grant AEI-PID2021-122792NA-I00 funded by MCIN/ AEI/10.13039/501100011033 and “ERDF, A way of making Europe”. This is contribution 1742 from the ARC Centre of Excellence for Core to Crust Fluid Systems (http://www.ccfs.mq.edu.au) and 1511 from the GEMOC Key Centre (http://www.gemoc.mq.edu.au).Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.chemgeo.2022.121039.We present the first global review on the Sm-Nd and Lu-Hf isotope systematics of the mantle; it includes all published data on peridotites and pyroxenites from all tectonic settings (>1100 combined Hf-Nd analyses), as well as previous compilations for oceanic basalts and material such as oceanic and continental sediments. We first provide a comprehensive overview of the main reservoirs and mechanisms accounting for the contrasting variability of radiogenic isotope systematics in the sub-oceanic mantle and the relative homogeneity of its volcanic products, highlighting the paradigm change promoted by the use of Hf isotopes. Secondly, we summarize the different models invoked to explain the decoupling/(re-)coupling of Hf and Nd isotopes. Decoupling above the mantle array is often related to melt-peridotite interaction involving ancient protoliths, whereas coupled Hf-Nd or decoupling below the array are shown to be insufficient criteria to exclude the involvement of such protoliths. The Hf-Nd isotope variability of the SCLM is then addressed using a tectono-thermal classification based on the Global Lithospheric Architecture Mapping (GLAM) project. The extreme variability that characterizes the cratonic SCLM reflects the long-term preservation of depleted signatures overprinted by ancient and recent metasomatic episodes. Refertilized SCLM domains fingerprinted by variably decoupled Hf-Nd isotope systematics record subduction-related processes, which also appears to be instrumental in the recycling of continental material into the convective mantle. We show that there is a critical “chicken-and-egg” question underpinning debates on the spatio-temporal evolution of the SCLM: whether ancient signatures are pre-existing in the lithosphere (e.g. “lithospheric memory” during refertilization) or introduced into the convective mantle (i.e. recycling). Importantly, our compilation shows that fertile lithologies such as pyroxenites can also carry extremely depleted isotopic signatures. In particular, delamination of gravitationally unstable, pyroxenite-rich arc roots represents a volumetrically significant flux of material characterized by ancient radiogenic Hf and basalt-like Nd-isotope compositions that can, once recycled, account for the Hf variability observed between MORB suites. In this context, the characteristic HIMU-like or coupled Hf-Nd signatures observed in garnet-pyroxenite layers from orogenic peridotite massifs probably reflects long-term processing (re-coupling) of recycled lithospheric material in the convective mantle. In contrast, continental dispersal during rifting (± plume-related processes) appears to be mostly limited to buoyant SCLM remnants in the oceanic lithosphere, and these are unlikely to be recycled unless previously refertilized. This work brings a new geodynamic perspective to the ancient signatures identified as chemical and isotopic heterogeneities in the oceanic lithosphere and convective mantle. These conclusions imply that (1) subduction is the main driver of mass transfer between lithosphere and asthenosphere and (2) the long-term evolution of the Earth's mantle and crust are directly linked to convergent plate-tectonic processes, at least since the Archean.Grant FJC2018-036729 funded by MCIN/AEI/10.13039/501100011033 and “ESF, Investing in your future”Grant AEI-PID2021-122792NA-I00 funded by MCIN/ AEI/10.13039/501100011033 and “ERDF, A way of making Europe

Left atrial voltage, circulating biomarkers of fibrosis, and atrial fibrillation ablation. A prospective cohort study.

Aims To test the ability of four circulating biomarkers of fibrosis, and of low left atrial voltage, to predict recurrence of atrial fibrillation after catheter ablation. Background Circulating biomarkers potentially may be used to improve patient selection for atrial fibrillation ablation. Low voltage areas in the left atrium predict arrhythmia recurrence when mapped in sinus rhythm. This study tested type III procollagen N terminal peptide (PIIINP), galectin-3 (gal-3), fibroblast growth factor 23 (FGF-23), and type I collagen C terminal telopeptide (ICTP), and whether low voltage areas in the left atrium predicted atrial fibrillation recurrence, irrespective of the rhythm during mapping. Methods 92 atrial fibrillation ablation patients were studied. Biomarker levels in peripheral and intra-cardiac blood were measured with enzyme-linked immunosorbent assay. Low voltage (<0.5mV) was expressed as a proportion of the mapped left atrial surface area. Follow-up was one year. The primary endpoint was recurrence of arrhythmia. The secondary endpoint was a composite of recurrence despite two procedures, or after one procedure if no second procedure was undertaken. Results The biomarkers were not predictive of either endpoint. After multivariate Cox regression analysis, high proportion of low voltage area in the left atrium was found to predict the primary endpoint in sinus rhythm mapping (hazard ratio 4.323, 95% confidence interval 1.337–13.982, p = 0.014) and atrial fibrillation mapping (hazard ratio 5.195, 95% confidence interval 1.032–26.141, p = 0.046). This effect was also apparent for the secondary endpoint. Conclusion The studied biomarkers do not predict arrhythmia recurrence after catheter ablation. Left atrial voltage is an independent predictor of recurrence, whether the left atrium is mapped in atrial fibrillation or sinus rhythm

Explaining spatial variation in housing construction activity in Turkey

In Turkey, there has been a strong policy narrative that has emphasized the importance of construction activity as a driver of economic growth. This has given shape to a central state-led policy regime that has sought to ensure that planners and other urban policy makers develop plans and strategies that support construction activity. Against this backdrop, and a recent history of uneven spatial development, this paper seeks to understand what this policy imperative might mean for housing construction activity in different provinces. It seeks to reflect on both the relationship between the state and the market, and the interaction between state policies, economic drivers and levels of construction activity. The evidence presented in the paper suggests that uneven spatial development might be explained in different ways in different provinces. Although, in many cases, patterns of construction activity are consistent with economic fundamentals, there are important exceptions in some regions where arguably activity levels are at odds with prior expectations

Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action

Background Patterns of food intake and prevalent osteoarthritis of the hand, hip, and knee were studied using the twin design to limit the effect of confounding factors. Compounds found in associated food groups were further studied in vitro. Methods Cross-sectional study conducted in a large population-based volunteer cohort of twins. Food intake was evaluated using the Food Frequency Questionnaire; OA was determined using plain radiographs. Analyses were adjusted for age, BMI and physical activity. Subsequent in vitro studies examined the effects of allium-derived compounds on the expression of matrix-degrading proteases in SW1353 chondrosarcoma cells. Results Data were available, depending on phenotype, for 654-1082 of 1086 female twins (median age 58.9 years; range 46-77). Trends in dietary analysis revealed a specific pattern of dietary intake, that high in fruit and vegetables, showed an inverse association with hip OA (p = 0.022). Consumption of 'non-citrus fruit' (p = 0.015) and 'alliums' (p = 0.029) had the strongest protective effect. Alliums contain diallyl disulphide which was shown to abrogate cytokine-induced matrix metalloproteinase expression. Conclusions Studies of diet are notorious for their confounding by lifestyle effects. While taking account of BMI, the data show an independent effect of a diet high in fruit and vegetables, suggesting it to be protective against radiographic hip OA. Furthermore, diallyl disulphide, a compound found in garlic and other alliums, represses the expression of matrix-degrading proteases in chondrocyte-like cells, providing a potential mechanism of action

Plume-subduction interaction forms large auriferous provinces

Gold enrichment at the crustal or mantle source has been proposed as a key ingredient in the production of giant gold deposits and districts. However, the lithospheric-scale processes controlling gold endowment in a given metallogenic province remain unclear. Here we provide the first direct evidence of native gold in the mantle beneath the Deseado Massif in Patagonia that links an enriched mantle source to the occurrence of a large auriferous province in the overlying crust. A precursor stage of mantle refertilisation by plume-derived melts generated a gold-rich mantle source during the Early Jurassic. The interplay of this enriched mantle domain and subduction-related fluids released during the Middle-Late Jurassic resulted in optimal conditions to produce the ore-forming magmas that generated the gold deposits. Our study highlights that refertilisation of the subcontinental lithospheric mantle is a key factor in forming large metallogenic provinces in the Earth’s crust, thus providing an alternative view to current crust-related enrichment models.Funding for this study has been provided by Millennium Science Initiative through Millennium Nucleus for Metal Tracing along Subduction Grant NC130065. Additional support was provided by FONDAP project 15090013 ‘Centro de Excelencia en Geotermia de Los Andes, CEGA’, FONDECYT projects #11140005 and #1140780, and DID-UACh project #S-2015-52. Additional funding for LA-ICP-MS analyses of sulfides at Macquarie University was provided by RYC-2015-17596. Minerals Targeting International Pty Ltd is acknowledged for providing directions regarding suitable sample sites for gold-bearing xenoliths. S.T. thanks CONICYT 21170857 for providing support through a PhD scholarship

A hand-guided robotic drill for cochleostomy on human cadavers

Background: An arm supported robotic drill has been recently demonstrated for preparing cochleostomies in a pilot research clinical trial. In this paper, a hand-guided robotic drill is presented and tested on human cadaver trials. Methods: The innovative smart tactile approach can automatically detect drilling mediums and decided when to stop drilling to prevent penetrating the endosteum. The smart sensing scheme has been implemented in a concept of a hand guided robotic drill. Results: Experiments were carried out on two adult cadaveric human bodies for verifying the drilling process and successfully finished cochleostomy on three cochlea. The advantage over a system supported by a mechanical arm includes the flexibility in adjusting the trajectory to initiate cutting without slipping. Using the same concept as a conventional drilling device, the user will also be benefit from the lower setup time and cost, and lower training overhead. Conclusion: The hand-guided robotic drill was recently developed for testing on human cadavers. The robotic drill successfully prepared cochleostomies in all three cases

Noise Exposure on Human Cochlea During Cochleostomy Formation Using Conventional and a Hand Guided Robotic Drill

Queen Elizabeth Hospital Birmingham Charity; Brunel University London

Phenotype of ARDS alveolar and blood neutrophils

RATIONALE: Acute respiratory distress syndrome is refractory to pharmacological intervention. Inappropriate activation of alveolar neutrophils is believed to underpin this disease's complex pathophysiology, yet these cells have been little studied. OBJECTIVES: To examine the functional and transcriptional profiles of patient blood and alveolar neutrophils compared with healthy volunteer cells, and to define their sensitivity to phosphoinositide 3-kinase inhibition. METHODS: Twenty-three ventilated patients underwent bronchoalveolar lavage. Alveolar and blood neutrophil apoptosis, phagocytosis, and adhesion molecules were quantified by flow cytometry, and oxidase responses were quantified by chemiluminescence. Cytokine and transcriptional profiling were used in multiplex and GeneChip arrays. MEASUREMENTS AND MAIN RESULTS: Patient blood and alveolar neutrophils were distinct from healthy circulating cells, with increased CD11b and reduced CD62L expression, delayed constitutive apoptosis, and primed oxidase responses. Incubating control cells with disease bronchoalveolar lavage recapitulated the aberrant functional phenotype, and this could be reversed by phosphoinositide 3-kinase inhibitors. In contrast, the prosurvival phenotype of patient cells was resistant to phosphoinositide 3-kinase inhibition. RNA transcriptomic analysis revealed modified immune, cytoskeletal, and cell death pathways in patient cells, aligning closely to sepsis and burns datasets but not to phosphoinositide 3-kinase signatures. CONCLUSIONS: Acute respiratory distress syndrome blood and alveolar neutrophils display a distinct primed prosurvival profile and transcriptional signature. The enhanced respiratory burst was phosphoinositide 3-kinase-dependent but delayed apoptosis and the altered transcriptional profile were not. These unexpected findings cast doubt over the utility of phosphoinositide 3-kinase inhibition in acute respiratory distress syndrome and highlight the importance of evaluating novel therapeutic strategies in patient-derived cells.This work was funded by a non-commercial grant from GSK, with additional support from The Wellcome Trust, Papworth Hospital, The British Lung Foundation and the NIHR Cambridge Biomedical Research Centre. DMLS holds a Gates Cambridge Scholarship; CS is in receipt of a Wellcome Trust Early Postdoctoral Research Fellowship for Clinician Scientists [WT101692MA].This is the author accepted manuscript. The final version is available from ATS Journals via http://dx.doi.org/10.1164/rccm.201509-1818O