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Porphyry-type deposits in the shallow crust (3–5 km) are formed from metal-rich fluids exsolved from underlying magma chambers (5–15 km). However, a direct volatile record of the fluid exsolution in the magma chamber is commonly lacking. Here, we analyze the compositions of apatite inclusions (in biotite and plagioclase phenocrysts and fully/partly included in zircon microphenocrysts) and the apatite in groundmass from the largest Cretaceous Luoboling porphyry Cu-Mo deposit in South China. In combination with thermodynamic models, we reconstructed the volatile behavior in the ore-forming magma. The analyzed apatites are magmatic in origin, without hydrothermal overprint, as indicated by their homogeneous cathodoluminescence (CL) and higher Cl and REE contents than typical hydrothermal apatite. Apatite inclusions fully enclosed in zircon show decreasing X C l A p / X O H A p (1.5–0.1) with increasing X F A p / X O H A p (0.4–3.3) and X F A p / X C l A p (0.5–21), and display a steep drop in X C l A p at approximately constant X O H A p in the ternary F-Cl-OH plot. These trends follow the modeled compositional trajectories of isobaric, H2O-saturated crystallization, indicating volatile exsolution during or before zircon crystallization in the magma chamber. Groundmass apatite crystals, phenocryst-hosted apatite inclusions, and apatite inclusions that are partially enclosed by zircon microphenocrysts have comparable volatile compositions, with much higher X F A p / X O H A p (1.7–78.8) and X F A p / X C l A p (2.3–37.5) but lower X O H A p and X C l A p than those fully enclosed in zircon. Compositional similarities between these crystals in different textural associations indicate that the phenocryst-hosted apatite inclusions do not preserve their original volatile records at the time of entrapment, and the volatile compositions were overprinted by later re-equilibration with the residual melt and the exsolved magmatic fluids. Given the porphyry magma is highly oxidized, and sulfides phases would be unstable in such circumstance, we suggest that volatile exsolution in the magma chamber is essential for Cl and Cu-Mo extraction from the melts and therefore the porphyry mineralization. In this study, only zircon-hosted apatite inclusions appear to best record the magmatic volatile compositions in a porphyry system. Therefore, using apatite hosted in other minerals or groundmass compositions to unravel magma volatile contents in porphyry Cu systems should be conducted with caution. [ABSTRACT FROM AUTHOR]

Bending loads can lead to local buckling in pipelines with kinked dents. The Finite Element Method is adopted to establish the numerical model of the pipeline with kinked dent. The local buckling failure mechanism of pipeline with kinked dent under bending load is investigated. In addition, the influence of parameters such as the dent depth, dent angle and pipe properties on the failure mode and ultimate compressive strain is analysed. It is found that the depth of the dent depth significantly affects the buckling failure mode and ultimate compressive strain. In addition, the larger the dent angle and the yield ratio, the smaller the ultimate compressive strain capacity. The larger the internal pressure and pipeline diameter thickness ratio, the larger the ultimate compressive strain. Based on the numerical results, the method for predicting the ultimate compressive strain of pipeline with kinked dent is proposed. [ABSTRACT FROM AUTHOR]

Metal complexation and speciation is the primary process responsible for metal transport and circulation in hydrothermal systems, during which stable and soluble metal complexes play a pivotal role. Here, we investigate the speciation of Os and the thermodynamic stability of Os(IV)‐Cl complexes in chloride‐bearing solutions at temperatures ranging from 150 to 600°C and pressure of 100 MPa through hydrolysis experiments. The results show that the dominant species of Os is OsCl62− at temperatures between 150 and 450°C and 100 MPa, gradually converting into Os(IV)‐OH‐Cl and Os(II)‐Cl complexes over 450°C. The equilibrium constant (ln K) (K = [HCl]4 ⨯ [Cl−]2/[OsCl62−]) between OsCl62− and water molecule is determined as ln K = (50.43 ± 4.633) − (54223 ± 2525.6)/T, and ΔrHmΘ and ΔrSmΘ are inferred to be (450.8 ± 21.00) kJ · mol−1 and (419.3 ± 38.52) J · mol−1 · K−1. Furthermore, the formation constant (ln β) of OsCl62− exhibits a change from −0.097 to −0.104 as temperatures increase from 150 to 400°C, while the change values in standard Gibbs free energy (ΔrGmΘ) for the hydrolysis reactions decrease with rising temperature, suggesting a temperature‐dependent thermodynamic stability of OsCl62−. Geochemical modeling further demonstrates that high solubility of OsCl62− could exist in low‐temperature and acidic fluids (≤300°C and pH < 5), or relatively high‐temperature and acidic‐neutral fluids (>300°C and pH < 7), primarily influenced by the Cl concentration. Acidic and near‐neutral fluids with high Cl concentration venting in the mid‐ocean ridge, back‐arc, and sediment‐hosted systems contribute more to dissolving and transporting Os from the lithosphere to the hydrosphere, thereby impacting the global ocean dissolved Os budget. Plain Language Summary: The rare and precious metal osmium is typically enriched in the deep Earth and associated mantle‐derived rocks. However, some submarine sediments and hydrothermal fluids may contain elevated levels of Os, suggesting a potential pathway for Os transport from the lithosphere to the hydrosphere. The key point is to clarify in what form and how Os transports from the deep Earth to the seawater. To achieve this goal, hydrolysis experiments were conducted to determine the speciation and stability of Os in chloride‐bearing solutions. The results revealed that OsCl62− can remain stable in low‐temperature, then convert into Os(IV)‐OH‐Cl and Os(II)‐Cl complexes over 450°C at ∼ NNO (Ni‐NiO) oxygen fugacity conditions. Quantitative relationship among Os solubility, chloride concentration, pH, and temperature was established, indicating that high Os solubility could exist in the low‐temperature and acidic fluids (≤300°C and pH < 5) or relatively high‐temperature and acidic‐neutral fluids (>300°C and pH < 7), such as those found in submarine vent fluids in mid‐ocean ridge, back‐arc, and sediment‐hosted systems. During ascent, these Os‐rich hydrothermal fluids can mix with seawater, thereby dominating Os transport and distribution in submarine hydrothermal systems. This study provides new evidence and insights into Os transport and enrichment mechanisms responsible for transporting Os from the lithosphere to the hydrosphere. Key Points: New experiments demonstrate the stability of OsCl62− in Cl‐rich hydrothermal fluids, highlighting its role in facilitating Os transportGeochemical modeling defined a quantitative relation among Os solubility, pH, Cl concentration, and temperatureAcidic and near‐neutral high‐Cl hydrothermal fluids contribute more to Os transport and distribution in the subseafloor [ABSTRACT FROM AUTHOR]

The floating toe deformity is classified as a forefoot deformity wherein the distal portion of the toe does not establish touch with the ground, resulting in a suspended or elevated position while the finger is in a relaxed state. At first, it garnered considerable interest as a complication It is worth noting that this condition is particularly common in children under the age of 8, which usually disappears as the individual reaches maturity. Studies have shown that with the aggravation of floating toe deformity, its adverse effects on patients' gait and overall quality of life also increase. Despite the prevalence of floating toe deformity in clinical settings, there is a lack of comprehensive literature investigating its underlying causes and potential preventive strategies. This scope review follows the preferred reporting items for systematic reviews and meta‐analyses extension for scoping reviews (PRISMA‐ScR) statement guidelines for scope reviews. The literature was obtained from various full‐text databases, including China National Knowledge Infrastructure Database (CNKI), Wanfang Database, PubMed, and Web of Science Database. Our search focused on published literature related to floating toes, Weil osteotomy, and distal metatarsal osteotomy, up until March 1, 2023. The literature search and data analysis are conducted by two independent reviewers. If there are any disagreements, a third researcher will participate in the discussion and negotiate a decision. Furthermore, two experienced foot and ankle surgeons conducted a thorough literature analysis for this review. Sixty‐two articles were included. Through the clinical analysis of the structural changes of the forefoot before and after operation, the classification of floating toe was described, the causes of pathological floating toe were summarized, and the possible intervention measures for the disease were put forward under the advice of foot and ankle surgery experts. We comprehensively summarize the current knowledge system about the etiology of floating toe and put forward the corresponding intervention strategy. We recommend that future studies will focus on the improvement of surgical procedures, such as the combination of Weil osteotomy, proximal interphalangeal (PIP) arthrodesis and flexor tendon arthrodesis. [ABSTRACT FROM AUTHOR]