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Magnetite is common in various magmatic and hydrothermal ore deposit types, and its trace element geochemistry has become increasingly used in ore genesis studies and mineral exploration. While fractional crystallization has been shown to influence the chemistry of igneous magnetite, the extent to which this process regulates the trace element composition of hydrothermal magnetite remains poorly understood. In this study, we analyzed trace elements in hydrothermal magnetite from the Baijian Fe-(Co) skarn deposit in eastern China and used Rayleigh and equilibrium fractionation modeling to demonstrate the importance of magnetite precipitation in controlling fluid and magnetite chemistry during Fe skarn mineralization. The Baijian Fe-(Co) skarn deposit has three stages of magnetite. From early Mag-1 to later Mag-2 and Mag-3, the concentrations of compatible elements (Ni and V) decrease, whereas those of incompatible elements (Zn, Mn, and Co) increase. There are obvious trends of increasing incompatible/compatible element ratios (e.g., Co/Ni, Zn/V, and Zn/Ni) and decreasing compatible/incompatible element ratios (e.g., V/Mn, Ni/Mn, and V/Co) from Mag-1 to Mag-3, with strong correlations between each of these ratios. Such systematic trace element variations in successive stages of magnetite can be best explained by increasing degrees of fractional crystallization with time. The wide range of incompatible/compatible element ratios (spanning 2-4 orders of magnitude) in Mag-2 and Mag-3 suggests that magnetite crystallization follows a process akin to Rayleigh fractionation. Results from this study highlight the significant role that magnetite crystallization during skarn formation has on the trace element chemistry of this mineral. Moreover, as the crystallization of magnetite progresses, the Co/Fe ratio of residual hydrothermal fluids is elevated, which favors the precipitation of Co in late-stage sulfides. This process helps to explain why some Fe skarn deposits, as well as magnetite-rich iron oxide-apatite and iron oxide-copper-gold deposits, are potentially important economic sources for Co, currently necessary as one component in Li-ion batteries. [ABSTRACT FROM AUTHOR]

Determining the source and history of hydrothermal fluids are key to better understanding the genesis of lode gold deposits. However, it is difficult to rigorously constrain the fluid history because the fluids typically have a prolonged and complicated history that may obscure the original source signature. We integrate textural characterization, trace element geochemistry, and in situ oxygen isotope analyses of quartz covering three major paragenetic stages of the world-class Dongping lode gold deposit to fingerprint the ore-fluid source and document the deposit's complex hydrothermal history. Six quartz generations were identified from three paragenetic stages. They consistently display small to large ranges in δ18O values from 13.1 to 0.6‰ (VSMOW), which correspond to calculated δ18O values of 7.4 to –6.0‰ for the quartz-forming fluids. These isotope data are intermediate between the δ18O ranges of magmatic fluids and meteoric water and thus are best interpreted in terms of episodic fluxes of magmatically derived fluids and their subsequent mixing with variable proportions of external meteoric water. Our results highlight the important role of magmatic hydrothermal fluids and their mixing with meteoric water to form the giant Dongping gold deposit. Given the high abundance of quartz that typically spans the entire mineralization process of lode gold deposits, we envisage the versatility and reliability of in situ oxygen isotope analysis of well-characterized quartz in deciphering the origin and complex evolution history of gold-forming fluids. [ABSTRACT FROM AUTHOR]

Halogens (Cl, Br, and I) are major complexing agents for metal ions, and their ratios (Br/Cl and I/Cl) have been used to determine the source and evolution of hydrothermal fluid. Halogen fractionation during hydrothermal fluid evolution, however, has been inferred from several studies, which poses problems in using halogen ratios as a fluid tracer. The Br/Cl and I/Cl ratios of scapolite are consistent with those ratios present in the coexisting fluid during scapolite formation, making this mineral particularly useful for understanding hydrothermal fluid evolution. To better understand halogen fractionation during vapor-brine phase separation, we conducted fluid inclusion microthermometry, major elements, and in situ halogens and Sr isotope analysis of scapolite formed from a high-salinity hydrothermal fluid during the vapor-brine phase separation at the Yixingzhai gold deposit, North China Craton. The studied scapolite has 1.84–3.41 wt% Cl, 389–806 ppm Br, 8.4–24.4 ppm I, and significantly high Br/Cl (6.1–14.7 × 10–3) and high I/Cl (91–302 × 10–6) molar ratios that likely result from the preferential incorporation of Br and I into the brine phase compared to Cl entering the vapor phase during fluid phase separation. Based on fluid inclusion microthermometry results, the Rayleigh fractionation simulation shows that the Br/Cl and I/Cl ratios of the brine are estimated to be up to 18 × 10–3 and 500 × 10–6 during the formation of scapolite. These results reveal halogen fractionation during the vapor-brine phase separation of hydrothermal fluids. This view has implications for interpreting the halogen systematics of scapolite and other minerals formed in similar environments, particularly when they are used as a fluid tracer. [ABSTRACT FROM AUTHOR]

The fresh latex was preserved using the composite preservative HY/NH3 for 1 ~ 5 d, regular sampling and solidification to prepare raw rubber. A sample with a latex maturation time of 1 d was used as a control sample to investigate the effect of maturation time of fresh latex on the composition and prop-erties of natural rubber. The natural rubber was characterised using instruments such as infrared spectros-copy, nuclear magnetic resonance crosslink density and tensile testing machines, respectively. The results showed that the maturation of fresh latex could reduce the content of impurities, ash and volatiles in raw rubber sheets, and improve the plasticity retention index and cross-link density. The scorch time, positive vulcanization time, torque difference of compounded rubber and tensile strength, tear strength, constant tensile stress of vulcanized rubber were all improved. The natural rubber prepared from the fresh latex for 3 d of maturation had the best overall performance, and the tensile strength and tear strength of vulcanized rubber reached were up to 20.47 MPa and 30.38 kN/m, respectively, an increase of 3.5% and 7.0% compared to the control sample. [ABSTRACT FROM AUTHOR]

Background: Enhancing awareness and use of pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) is vital to curb human immunodeficiency virus (HIV) spread. High-risk behaviors prevalent among sexually transmitted infection clinic outpatients underscore the need for increased PrEP/PEP education in this group., Aim: To investigate the effects of both onsite and online health education on the knowledge of, and willingness to use, PrEP and PEP among individuals receiving PEP services., Methods: Participants were drawn from a cohort study on PEP service intervention at an STD/AIDS outpatient clinic in designated HIV/AIDS hospitals in Beijing, conducted from January 1 to June 30, 2022. Health education was provided both onsite and online during follow-up. Surveys assessing knowledge of, and willingness to use, PrEP/PEP were administered at baseline and again at 24 wk post-intervention., Results: A total of 112 participants were enrolled in the study; 105 completed the follow-up at week 24. The percentage of participants with adequate knowledge of, and willingness to use, PrEP significantly increased from 65.2% and 69.6% at baseline to 83.8% and 82.9% at the end of the intervention (both P < 0.05). Similarly, those with adequate knowledge of, and willingness to use, PEP increased from 74.1% and 77.7% at baseline to 92.4% and 89.5% at week 24 ( P < 0.05). Being between 31 years and 40 years of age, having a postgraduate degree or higher, and reporting a monthly expenditure of RMB 5000 or more were found to be significantly associated with knowledge of PrEP and PEP (both P < 0.05)., Conclusion: The findings show that both onsite and online health education significantly improved the knowledge of, and increased willingness to use, PrEP and PEP in individuals utilizing PEP services., Competing Interests: Conflict-of-interest statement: All the authors declare that they have no conflict of interest., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)

Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://hbsn.amegroups.com/article/view/10.21037/hbsn-23-584/coif). The authors report that this work was supported by grant from the New Clinical Technology Project Foundation of the Southwest Hospital, Third Military Medical University (No. SWH2016JSTSYB-50). The authors have no other conflicts of interest to declare.

Background: Advancements in laparoscopic technology and a deeper understanding of intrahepatic anatomy have led to the establishment of more precise laparoscopic hepatectomy (LH) techniques. The indocyanine green (ICG) fluorescence navigation technique has emerged as the most effective method for identifying hepatic regions, potentially overcoming the limitations of LH. While laparoscopic left hemihepatectomy (LLH) is a standardized procedure, there is a need for innovative strategies to enhance its outcomes., Aim: To investigate a standardized cranial-dorsal strategy for LLH, focusing on important anatomical markers, surgical skills, and ICG staining methods., Methods: Thirty-seven patients who underwent ICG fluorescence-guided LLH at Qujing Second People's Hospital between January 2019 and February 2022 were retrospectively analyzed. The cranial-dorsal approach was performed which involves dissecting the left hepatic vein cephalad, isolating the Arantius ligament , exposing the middle hepatic vein, and dissecting the parenchyma from the dorsal to the foot in order to complete the anatomical LLH. The surgical methods, as well as intra- and post-surgical data, were recorded and analyzed. Our hospital's Medical Ethics Committee approved this study (Ethical review: 2022-019-01)., Results: Intraoperative blood loss during LLH was 335.68 ± 99.869 mL and the rates of transfusion and conversion to laparotomy were 13.5% and 0%, respectively. The overall incidence of complications throughout the follow-up (median of 18 months; range 1-36 months) was 21.6%. No mortality or severe complications (level IV) were reported., Conclusion: LLH has the potential to become a novel, standardized approach that can effectively, safely, and simply expose the middle hepatic vein and meet the requirements of precision surgery., Competing Interests: Conflict-of-interest statement: The authors declare no conflicts of interest for this article., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)