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Background: Caveolin-1, the scaffolding protein of cholesterol-rich invaginations, plays an important role in store-operated Ca2+ influx and its phosphorylation at Tyr14 (p-caveolin-1) is vital to mobilize protection against myocardial ischemia (MI) injury. SOCE, comprising STIM1, ORAI1 and TRPC1, contributes to intracellular Ca2+ ([Ca2+]i) accumulation in cardiomyocytes. The purified extract of steamed Panax ginseng (EPG) attenuated [Ca2+]i overload against MI injury. Thus, the aim of this study was to investigate the possibility of EPG affecting p-caveolin-1 to further mediate SOCE/[Ca2+]i against MI injury in neonatal rat cardiomyocytes and a rat model. Methods: PP2, an inhibitor of p-caveolin-1, was used. Cell viability, [Ca2+]i concentration were analyzed in cardiomyocytes. In rats, myocardial infarct size, pathological damages, apoptosis and cardiac fibrosis were evaluated, p-caveolin-1 and STIM1 were detected by immunofluorescence, and the levels of caveolin-1, STIM1, ORAI1 and TRPC1 were determined by RT-PCR and Western blot. And, release of LDH, cTnI and BNP was measured. Results: EPG, ginsenosides accounting for 57.96%, suppressed release of LDH, cTnI and BNP, and protected cardiomyocytes by inhibiting Ca2+ influx. And, EPG significantly relieved myocardial infarct size, cardiac apoptosis, fibrosis, and ultrastructure abnormality. Moreover, EPG negatively regulated SOCE via increasing p-caveolin-1 protein, decreasing ORAI1 mRNA and protein levels of ORAI1, TRPC1 and STIM1. More importantly, inhibition of the p-caveolin-1 significantly suppressed all of the above cardioprotection of EPG. Conclusions: Caveolin-1 phosphorylation is involved in the protective effects of EPG against MI injury via increasing p-caveolin-1 to negatively regulate SOCE/[Ca2+]i.

In view of the imperfection of the calculation method of horizontal frost heaving force in the design of L-shaped retaining wall in permafrost area, based on the Lifkin foundation model and the cooperative deformation principle between retaining wall and soil, a simplified calculation model of horizontal frost heave effect of L-shaped retaining wall with or without soil replacement behind the wall is established, and the proposed calculation model is solved by superposition principle and finite difference method. Furthermore, the water-thermal-mechanical coupling analysis software is developed by MATLAB. Combined with an engineering example, the horizontal frost heaving force obtained by using the proposed calculation method is compared with the field measured value, the corrected earth pressure value, the code empirical value and the simulation value of the coupling software. The results show that: (1) the horizontal frost heaving force obtained by the proposed calculation method is in good agreement with the field measured value and numerical simulation value, while the corrected earth pressure value and the code empirical value underestimate the effect of horizontal frost heaving force on the retaining wall; (2) compared with the code empirical value and field measured value, the horizontal frost heaving force obtained by the proposed calculation method presents two distribution modes of parabola and trapezoid along the wall height, which is more general; (3) the multifield coupling analysis shows that the frost heaving force trend obtained by the proposed calculation method is similar to the trend obtained by the coupling method, which indicates the feasibility of the calculation method and can provide some theoretical support and guidance for the design of L-shaped retaining wall in permafrost area.

The Malysheva emerald mine (Urals, Russia) boasts a long history and extraordinary emerald output. However, recent studies indicate that Malysheva emeralds share highly similar inclusion varieties, UV-visible-near infrared (UV-Vis-NIR) spectra, and compositional characteristics with other tectonic-magmatic-related (type I) emeralds from Zambia, Brazil, and Ethiopia. This similarity poses challenges for determination of the emeralds' origin. This paper systematically investigates the microscopy, spectroscopy, and trace element chemistry of Malysheva emerald samples and compiles previously reported compositional data for the aforementioned Type I emeralds. Based on this dataset, principal component analysis (PCA) and machine learning methods are employed to construct models for emerald provenance discrimination. The results have updated the provenance characteristics of Malysheva emeralds, confirming the solid phase component of their three-phase inclusions as siderite and revealing two UV-Vis-NIR spectral patterns. Furthermore, the unique infrared absorptions related to HDO and D2O molecules within the 2600–2830 cm−1 range were discovered, which can be indicative of the origin of Malysheva. The prediction results of the machine learning model demonstrate an accuracy rate of 98.7%, and for an independent validation set of Malysheva emeralds, the prediction accuracy reached 100%. The feature importance ranking of the model highlights trace elements and parameters strongly correlated with the emeralds' origin. These results illustrate the enormous potential of machine learning in the field of emerald origin determination, offering new insights into the traceability of precious gemstones. [ABSTRACT FROM AUTHOR]

Apatite major and trace element chemistry is a widely used tracer of mineralization as it sensitively records the characteristics of the magmatic-hydrothermal system at the time of its crystallization. Previous studies have proposed useful indicators and binary discrimination diagrams to distinguish between apatites from mineralized and unmineralized rocks; however, their efficiency has been found to be somewhat limited in other systems and larger-scale data sets. This work applied a machine learning (ML) method to classify the chemical compositions of apatites from both fertile and barren rocks, aiming to help determine the mineralization potential of an unknown system. Approximately 13 328 apatite compositional analyses were compiled and labeled from 241 locations in 27 countries worldwide, and three apatite geochemical data sets were established for XGBoost ML model training. The classification results suggest that the developed models (accuracy: 0.851–0.992; F1 score: 0.839–0.993) are much more accurate and efficient than conventional methods (accuracy: 0.242–0.553). Feature importance analysis of the models demonstrates that Cl, F, S, V, Sr/Y, V/Y, Eu*, (La/Yb)N, and La/Sm are important variables in apatite that discriminate fertile and barren host rocks and indicates that V/Y and Cl/F ratios and the S content, in particular, are crucial parameters to discriminating metal enrichment and mineralization potential. This study suggests that ML is a robust tool for processing high-dimensional geochemical data and presents a novel approach that can be applied to mineral exploration. [ABSTRACT FROM AUTHOR]

The homomorphic substitution of the garnet group is common in nature. Two rare color-changing andradite garnets are studied in this paper. One color changes from yellowish-green in the presence of daylight to maroon under incandescent light; the other color changes from brownish yellow to brownish red. In this study, conventional gemological instruments, infrared (IR) spectroscopy, ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy, Raman spectroscopy, and electron probe microanalysis (EPMA) were used to explore the gemology and coloration mechanisms of color-changing garnets. Experiments revealed that the color-changing gemstones in the study are andradite garnets. There are two transmission windows in the UV–Vis spectrum: the red region (above 650 nm) and the green region (centered at 525 nm). The chemical compositional analysis indicates that the samples are very low in Cr (<1 ppm) and high in Fe2+ (from 2.31 wt.% to 4.66 wt.%). The combined spectra and chemical compositional analysis show that Fe2+ is the main cause of the color change. Based on the IR spectrum (complex water peaks), UV–Vis–NIR spectrum (similar to that of Namibian andradite garnet), and chemical compositional analysis (low Cr content), it is concluded that color-changing andradite may be related to skarn rock genesis. [ABSTRACT FROM AUTHOR]

Based on the first-principles of density functional theory, we use the PBEsol + U method to calculate the lattice and electronic structures, as well as mechanical and optical properties of ThO2, PaO2 and UO2 and (Th, Pa)O2 and (U, Pa)O2. The results of structural optimization indicate that the PBEsol + U method can provide more accurate lattice and mechanical parameters for actinidebased oxide ThO2, PaO2, and UO2. The calculation results show that the lattice parameters and the bandgaps of ThO2, PaO2, and UO2 are consistent with the experimental values and other related theoretical values. In the meanwhile? the lattice parameters of (Th, Pa)O2 and (U, Pa)O2 are between ThO2 and UO2, while predicting the band gaps of (Th, Pa)O2 and (U, Pa)O2 are also between ThO2 and UO2. Electronic properties calculations indicate that PaO2 and UO2 are Mott insulators, while ThO2 is a charge-transfer insulator. These are consistent with experiments and theoretical conclusions. (Th, Pa)O2 and (U, Pa)O2 have significant spin polarization effects near the Fermi energy level, and the bands are mainly occupied by Pa-5f and U5f electronic state, respectively. Lastly, the real and imaginary parts and optical parameters of the optical dielectric functions of these systems are compared and analyzed. [ABSTRACT FROM AUTHOR]

Reactions of [[RhCl(COE)(IPr)].sub.2] (1) and [[RhCl(COE)(IMes)].sub.2] (2) (COE = cyclooctene; IPr = N,N'-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; IMes = N,N'-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) with the diphosphines [Ph.sub.2]P[(C[H.sub.2]).sub.n]P[Ph.sub.2] and 1,2-bis(diphenylphosphino)benzene (dppbz) give the N-heterocyclic carbene (NHC)-diphosphine-rhodium(I) complexes: RhCl(NHC)[[Ph.sub.2]P[(C[H.sub.2]).sub.n]P[Ph.sub.2]] [NHC = IPr, n = 1 (3); NHC = IMes, n = 1 (4); NHC = IPr, n = 2 (5); NHC = IMes, n = 2 (6); NHC = IPr, n = 4 (7); NHC = IMes, n = 4 (8)] and RhCl(NHC)(dppbz) [NHC = IPr (9); NHC = IMes (10)]. All the complexes are characterized by ¹H, [sup.31]P(¹H}, and [sup.13]C{¹H} NMR spectroscopy, elemental analysis, and mass spectrometry. Complexes 3, 7, and 9 are also characterized crystallographically. In benzene solution, the complexes decompose in the presence of [O.sub.2] with formation of the diphosphine dioxide, whereas reaction with CO leads to replacement of the NHC ligand to give known carbonyl-diphosphine complexes. Key words: rhodium, N-heterocyclic carbenes, bis(diphenylphosphino) ligands, crystallography. Resume : Les reactions du [[RhCl(COE)(IPr)].sub.2] (1) et du [[RhCl(COE)(IMes)].sub.2] (2) [COE = cyclooctene; IPr = N,N'-bis(2,6-diisopropylphenyl)imidazoline-2-ylidene; IMes = N,N'-bis(2,4,6-trimethylphenyl)imidazoline-2-ylidene] avec les diphosphines [Ph.sub.2]P[(C[H.sub.2]).sub.n]P[Ph.sub.2] et 1,2-bis(diphenylphosphino)benzene (dppbz) conduisent a la formation de complexes carbene N-heterocyclique (NHC)-diphosphine-rhodium(I): RhCl(NHC)[[Ph.sub.2]P[(C[H.sub.2]).sub.n]P[Ph.sub.2]] [NHC = IPr, n = 1 (3); NHC = IMes, n = 1 (4); NHC = IPr, n = 2 (5); NHC = IMes, n = 2 (6); NHC = IPr, n = 4 (7); NHC = IMes, n = 4 (8)] et RhCl(NHC)(dppbz) [NHC = IPr (9); NHC = IMes (10)]. Tous les complexes ont ete caracterises par des analyses elementaires, par spectroscopie RMN du ¹H, du [sup.31]P{¹H} et du [sup.13]C{¹H} et par spectrometrie de masse. Les complexes 3, 7 et 9 ont aussi ete caracterises par diffraction des rayons X. En solution dans le benzene, les complexes se decomposent en presence de [O.sub.2] avec formation d'oxyde de diphosphine, alors qu'une reaction avec le CO conduit au remplacement du ligand NHC pour conduire aux complexes carbonyl-diphosphines connus. Mots-cles : rhodium, carbenes N-heterocycliques, ligands bis (diphenylphosphino), cristallographie. [Traduit par la Redaction], Introduction A just-published special issue of European Journal of Inorganic Chemistry demonstrates the growing interest in transition-metal N-heterocyclic carbene (NHC) complexes. (1) Seven of the papers in the issue are [...]