Search Results (1,160)

The thermal history of petroliferous basins controls the thermal evolution of source rocks and the diagenetic evolution of reservoirs. However, although various thermal events are common in such basins, previous studies have largely focused on the outcomes of thermal anomalies rather than systematically evaluating the spatiotemporal extent of their thermal effects. This oversight has impeded accurate assessment of source rock maturation and the timing of hydrocarbon accumulation. This study takes the Baiyun Deep Water Area in the Pearl River Mouth Basin as a case study, aiming to identify types of thermal events and systematically evaluate the extent of their impacts using geologic thermometers, numerical simulations, and measured data. Magmatic activity and hydrocarbon charging are two widely distributed types of thermal events in this area. Apatite fission track (AFT) data reveal two magmatic underplating events in the southern part of the area at 20 Ma and 10 Ma, which led to a rapid increase in vitrinite reflectance (R_o) in the overlying strata. COMSOL Multiphysics 6.2 simulations of the B6-1 diapir show that its thermal impact extends laterally up to 10 km, with the Wenchang Formation source rocks within 2 km of the diapir rapidly heating to 310 °C and reaching over-maturity. Abnormally high homogenization temperatures recorded by saline inclusions associated with hydrocarbon inclusions provide evidence of thermal anomalies induced by hydrocarbon charging. By reconstructing the trapping depths of these inclusions, the timing of their formation was determined. Comparison with normal burial-thermal histories indicates that their homogenization temperatures are 20–30 °C higher than the ambient formation temperatures. Current thermal anomalies in the Enping Formation reservoir of Well K18-1, caused by ongoing hydrocarbon charging, were simulated using COMSOL. The results show that hydrocarbon charging only causes mild thermal anomalies confined to the reservoir and adjacent strata, with a temperature increase of about 29 °C. Present-day measured vitrinite reflectance data further confirm that hydrocarbon charging does not lead to an increase in R_o. Clarifying the types and effects of thermal events is essential for accurately reconstructing the thermal evolution of source rocks and the history of hydrocarbon accumulation. This study provides a new methodology for geothermal field research in petroliferous basins. By integrating AFT, R_o, and fluid inclusion analyses, we reveal past thermal events, and through numerical simulation, quantify the spatiotemporal influence of magmatic activity and hydrocarbon charging on the geothermal field. Full article

Dahua in Guangxi is an important soft jade mining area in southern China. Despite this, research on the nephrite from this region, particularly on the coloring mechanism of black nephrite, remains limited. This study systematically investigates the gemological, mineralogical, and geochemical properties of black nephrite from Dahua. Petrographic analysis reveals that tremolite is the primary mineral, with clinochlore and apatite as associated minerals. Tremolite (SiO₂: 58.00 wt%; MgO: 24.75 wt%; CaO: 12.46 wt%) in Dahua nephrite is close to the theoretical values of tremolite. Chlorite thermometry indicates formation temperatures of 240 °C and 328 °C. Geochemical analysis of the samples shows enrichment in light rare earth elements (LREEs), flat heavy rare earth element (HREEs) patterns, and Ce and Eu anomalies. The Mg²⁺/(Mg²⁺ + Fe²⁺) ratio was below 0.06. In the c(Ca²⁺), c(Mg²⁺), and c(Fe²⁺ + Fe³⁺) ternary diagram, the amphibole plots close to the Dahua green nephrite, suggesting a similar genetic environment and supporting a contact metasomatic origin for the amphibole. Combined with the geological setting, mineralization was driven by hydrothermal fluids from diabase magma, which introduced Si and heat, with Ca and Mg being mobilized from the dolomitic limestone host rocks. These findings contribute to the understanding of nephrite formation in Dahua, distinguishing it from nephrite from other regions and providing a foundation for future studies on the geochemical and mineralogical characteristics of nephrite. Full article

Pegmatites with miarolitic cavities have not previously been reported from the Larsemann Hills, East Antarctica, and their age and origin remain poorly constrained. We report the first geochemical and geochronological data for fluorapatite from a newly discovered pegmatite with miarolitic cavities in the Larsemann Hills. Large Fe-rich fluorapatite crystals (up to 5 cm) contain abundant oriented monazite-(Ce) inclusions and display elevated REE (1397–7966 ppm), relatively high Y (945–4192 ppm), and low Sr (52.2–83.5 ppm). Their trace-element signatures plot within the fields of partial melts, high-grade metamorphic rocks, and evolved fluid-rich magmatic systems. U–Pb dating of fluorapatite yields concordant ages of 519 ± 4 Ma (ID-TIMS) and 521 ± 31 Ma (LA-ICP-MS), indicating crystallization during the D₄ stage of the Pan-African orogeny. The isotopic equilibrium between apatite and monazite inclusions suggests synchronous formation and late-stage fluid overprinting. Combined geological, geochemical, and isotopic evidence shows that the pegmatite formed in situ as a product of anatexis of the Broknes paragneisses and evolved within a volatile-rich magmatic–hydrothermal system. These results provide the first direct age constraints on pegmatites with miarolitic cavities in Antarctica and shed new light on the final stages of East Gondwana assembly. Full article

Modern bioimplants increasingly depend on surface-engineered functionality to elicit adaptive biological responses. One promising strategy involves the electrodeposition of bioresponsive elements such as magnesium (Mg), which plays a critical role in osseointegration. In this study, we present a novel approach for modifying anodized zirconia nanotubes (ZrNTs) via Mg decoration using electrochemical deposition. A controlled pulsed cathodic linear sweep protocol was employed to control Mg deposition behaviour, enabling reduced clustering and improved spatial distribution. Notably, ultraviolet (UV) irradiation was found to influence Mg adsorption dynamics, revealing a distinct pattern of interaction. Comprehensive surface characterization was conducted to assess nanotube morphology, Mg adherence, and distribution. These modified surfaces were subsequently evaluated for their potential in further functionalization, targeting surface chemistries conducive to biomaterial viability. The biomineralization capacity of Mg-decorated ZrNTs was systematically investigated using electrochemical impedance spectroscopy (EIS) and Tafel analysis, demonstrating enhanced apatite formation and improved corrosion resistance. This work establishes Mg decoration of ZrNTs as a viable route for developing bioactive, corrosion-resistant implant surfaces. Full article

In recent decades, ion-adsorption-type rare earth element (iREE) deposits have been widely documented in the weathering crusts of granitic and volcanic rocks and their geological characteristics and genetic mechanisms extensively studied. Ion-adsorption-type REE mineralization was documented for the first time in the weathered crust overlying the epimetamorphic rocks in Ningdu County, China. In contrast to well-documented granite-derived weathering profiles, investigations of epimetamorphic rocks as protoliths for such REE deposits remain limited, particularly regarding the mineralogy of REE-bearing phases and the geochronology and geochemistry of their parent rocks. To address this gap, the present study combines comprehensive petrographic and mineralogical analyses of REE-mineralized Shenshan Formation phyllites with the U–Pb dating of zircon and apatite and trace element geochemical investigations. U–Pb zircon and apatite geochronology yields a protolith age of ca. 785 Ma for Shenshan Formation metamorphic rocks, consistent with mid-Neoproterozoic magmatism. REE-bearing minerals in the Shenshan Formation phyllites comprise allanite-(Ce), apatite, cerianite-(Ce), monazite-(Ce), rhabdophane-(La), rutile, Y-bearing thorianite and xenotime-(Y). Among these, apatite is the most abundant and likely the principal source of ionic REEs in the deposit. Ti-in-zircon thermometry indicates crystallization temperatures of 641–749 °C (mean ~704 °C), reflecting a prolonged magmatic–hydrothermal evolution. This extended history chiefly controlled the differentiation and redistribution of rare earth elements (REEs), thus governing their availability for subsequent supergene enrichment. Zircon-based oxygen fugacity (fO₂) estimates a range from −31.4 to −9.9 (mean −17.9), consistent with reduced magmatic conditions. Trace element correlation diagrams for zircon and apatite indicate that the intrusion underwent an extensive fractional crystallization of accessory phases (zircon, monazite, apatite, titanite, rutile) and plagioclase. The distribution patterns of trace elements further suggest that the Shenshan Formation protolith formed in a continental margin arc or arc-related orogenic belt setting, with geochemical signatures characteristic of an S-type granite. The Shenshan Formation phyllites in southern Jiangxi exhibit high REE abundances and host a labile assemblage of weatherable REE-bearing minerals, providing an optimal material framework for ion-adsorption-type REE deposits and indicating substantial mineralization potential. Full article

Ion-adsorption rare earth element (REE) deposits represent strategic critical resources in China, which were traditionally considered to be predominantly hosted in granite weathering crusts. However, the recent discovery of new deposit types within the weathering crusts of shallow metamorphic rocks in South China has opened up novel exploration frontiers, while research on their metallogenic mechanisms remains insufficient. To elucidate the REE enrichment mechanisms in shallow metamorphic rock weathering crusts, this study focuses on the Getengzui ion-adsorption REE deposit in southern Jiangxi Province. Twenty-four samples were collected from the weathering crust profiles of the Qingbaikouan Shenshan and Kuli Formations. Multiple analytical approaches were employed, including major and trace element analysis, Chemical Index of Alteration (CIA), Base Leaching Index (BA), and quantitative evaluation of element mass transfer coefficients (τ). Trace element spider diagrams, REE distribution patterns, and A-CN-K diagram analysis were also utilized. The results reveal that the weathering crusts have progressed to the middle–late stage of chemical weathering. The average CIA value is 83 for the middle-upper part of the completely weathered horizon in the Kuli Formation. In contrast, for the completely weathered horizon in the Shenshan Formation, the value is 86. Intense chemical weathering has resulted in the near-complete decomposition of primary silicate minerals and extensive leaching of base cations. This progress has created an acidic pore water environment, which is critical for REE mobilization. REEs exhibit characteristics of in situ secondary enrichment, with significant enrichment of ΣREE in the middle-upper part of the completely weathered horizon. The peak τ(ΣREE) values reach 0.78 and 2.43 for the Kuli and Shenshan Formations, respectively. Apatite dissolution is identified as the primary source of REE ions. Differences exist in the geochemical mobility sequences of elements between the two formations. REE enrichment is controlled by multi-stage geochemical barriers, including an oxidation barrier and a clay adsorption barrier. The oxidation barrier preferentially fixes Ce⁴⁺, whereas the clay adsorption barrier serves as the dominant mechanism for large-scale REE enrichment. Parent rock lithology is the primary factor governing the efficiency, scale, and fractionation characteristics of REE enrichment. The Kuli Formation is favorable for forming the thick, large-scale orebodies enriched in light rare earth elements (LREEs). In the contrast, the Shenshan Formation tends to host higher-grade orebodies, characterized by a relatively balanced ratio of LREEs and heavy rare earth elements (HREEs). This study clarifies the main controlling factors for ion-adsorption REE mineralization in two shallow metamorphic rocks. It thereby provides a theoretical basis for future exploration. This framework is applicable to analogous REE resources within shallow metamorphic rock distributions across South China and nationwide. Full article

The Guposhan ore field, located in the Nanling metallogenic belt, is well known for large-scale Sn-W mineralization genetically linked to the Late Jurassic Guposhan pluton. The Lisong pluton, a product of regional magmatism, occurs in the central part of the Guposhan ore field. However, the critical factors responsible for the absence of intensive Sn polymetallic mineralization in the Lisong pluton remain poorly understood. Our geochronological results show that the coarse-grained hornblende-bearing and hornblende-free biotite monzogranites of the Lisong pluton were emplaced at 162.9 ± 1.5 Ma and 162.2 ± 2.3 Ma, respectively, which are contemporaneous with the Guposhan pluton. Geochemically, these intrusions are characterized by high SiO₂, Al₂O₃, and total alkalis (K₂O + Na₂O), high Ga/Al ratios (3.09–3.69), and peraluminous compositions (A/CNK = 1.15–1.23), consistent with high K calc-alkaline A-type granites. Similar to the adjacent Guposhan pluton, the Lisong granites yield variable _εHf(t) values from −3.0 to 5.7, apatite ⁸⁷Sr/⁸⁶Sr ratios of 0.69747–0.71190, and old two-stage Hf model ages (T_DM2) of 0.85–1.40 Ga. These features suggest that the Lisong and Guposhan granites may share a common magma source involving mixing of crustal and mantle-derived melts. Apatite grains from the Lisong granites display negative Eu anomalies (δEu = 0.03–0.22) and near-normal to positive Ce anomalies (δCe = 0.99–1.07), which we interpret to reflect plagioclase fractional crystallization and reduced melt conditions, respectively. Bulk rock geochemistry and multi-element systematics of the Lisong granites indicate that they represent early-stage magmatic products. Their relatively low differentiation signatures were unfavorable for Sn enrichment and mineralization in the melt, which likely explains the lack of intensive Sn polymetallic mineralization in the Lisong pluton. Full article

Iron oxide–copper–gold (IOCG) deposits are widespread throughout the Carajás Province, Brazil, reflecting multiple Precambrian hydrothermal events. The Aquiri region is a relatively unexplored geological frontier in the northwestern Carajás Province. The AQW2 IOCG deposit is hosted by a Neoarchean mafic intrusive suite within metavolcano–sedimentary rocks. The pre-mineralization (Na and Na-K) and mineralization (Fe-Ca and Fe-P) hydrothermal stages appear as replacement fronts and as cement within ductile-deformed breccias. Late-mineralization (Fe-K, chlorite, and calcic-rich) assemblages occur in multidirectional veins controlled by brittle structures. Early- and main-mineralization apatite (Ap I-III) is enriched in F, Mn, and Sr, depleted in Y, shows unusually high Fe and Si (Ap III), and exhibits a pronounced positive Eu anomaly (Ap II). These characteristics indicate an alkaline fluid composition, substantial fluid–rock interaction, and episodic CO₂ degassing with the release of overpressured fluids, resulting in multiple brecciation events. A rapid decrease in temperature due to boiling is interpreted as a principal mechanism for copper precipitation. Late-mineralization apatite (Ap V–VI) is characterized by relatively higher Cl, Y, and LREE contents, lower Sr and Mn, and negative Eu-anomaly ratios, suggesting control by shallower paleostructures and more oxidizing conditions associated with the influx of basinal brines. These results highlight the evolution of the AQW2 deposit within a broader IOCG system and provide new insights into the metallogenic processes responsible for copper resources essential to the clean energy transition. Full article

Mesoporous bioactive glass nanoparticles (MBGNs) are promising for bone tissue engineering; however, surgical site infection and oxidative stress often compromise regeneration. To address this, MBGNs co-doped with cerium (Ce), zinc (Zn), and strontium (Sr) were synthesized using a microemulsion-assisted sol-gel route (xCe-yZn-Sr-MBGNs; x = 0, 1, 2; y = 0, 0.5, 1). The resulting spherical nanoparticles (150–200 nm) exhibited a mesoporous structure with a specific surface area of (~340–425 m²/g), sustained ion release, and apatite formation in simulated body fluid. In vitro evaluations with MC3T3-E1 pre-osteoblasts demonstrated dose-dependent cytocompatibility, specifically in the co-doped formulations; however, higher Ce concentrations (2Ce-yZn-Sr-MBGNs) reduced viability following prolonged exposure. Crucially, the 1Ce-1Zn-Sr-MBGNs significantly enhanced osteogenic differentiation, as evidenced by a two-fold increase in osteogenic marker gene expression and a ~45% increase in calcium mineral deposition compared to undoped MBGNs within 14 days. Moreover, these particles accelerated cell migration, achieving ~70% scratch-wound closure within 24 h. Furthermore, 1Ce-1Zn-Sr-MBGNs displayed strong radical scavenging capacity and potent antibacterial activity against S. aureus and P. aeruginosa. These findings indicated that 1Ce-1Zn-Sr-MBGNs exhibited multiple therapeutic effects, including antibacterial, radical-scavenging, and osteogenic effects. By optimizing dopant ratios, these multifunctional nanomaterials emerge as promising candidates for next-generation bone grafts or implant coatings. Within the scope of this study, they demonstrated the capacity to simultaneously address three critical challenges in bone healing: controlling infection, mitigating oxidative stress, and promoting mineralized tissue formation. While these in vitro results provide a robust foundation, further in vivo validation is warranted to confirm their efficacy within complex physiological environments. Full article

In this study, the occurrence and leachability of rare earth elements and yttrium (REY) in medium-rank coal—meta-bituminous B coal from the southwestern part of the Upper Silesian Coal Basin in Poland—were investigated. The coal samples contained variable amounts of siderite, dolomite, calcite, kaolinite, illite, quartz, apatite, and pyrite in their mineral composition. A five-step sequential chemical leaching procedure was used, including deionized water, 3% HCl, 5% HNO₃, 10% HNO₃ with microwave assistance, and concentrated HCl–HF also with microwave assistance. The highest concentrations of ∑REY were observed in seam 404/1. Light REY (LREY) dominated the REY composition (>75%), while heavy REY (HREY) accounted for less than 10%. The chondrite-normalised REY patterns and total REY content indicate a clastic origin of REY-bearing minerals. The most efficient leaching occurred in stages IV and V. The solutions from stages I–III preferentially mobilised critical REY, while those from stages IV–V reflected the REY distribution in the coal. Based on the C_outl index, both coal and leachates from the later stages are classified as prospective REY resources. However, absolute REY concentrations should be considered when interpreting C_outl values. The positive correlation between apatite and kaolinite contents and ∑REE concentrations suggests their role in REY enrichment. Full article

Phosphatic bioclastic laminae distributed along bedding planes have been recently discovered within the Jurassic Lianggaoshan Formation shale in the eastern Sichuan Basin. However, their characteristics and potential as shale oil and gas reservoirs remain unclear. To reveal their microscopic pore structure characteristics and development model, this study focuses on samples of phosphatic bioclastic laminae obtained from drilling cores in the Fuxing area of eastern Sichuan. A multi-scale analytical approach was employed, integrating micro-X-ray fluorescence spectroscopy (μ-XRF), field emission scanning electron microscopy (FE-SEM), nitrogen adsorption, nuclear magnetic resonance (NMR), and geochemical analyses. The results indicate that the phosphatic bioclastic laminae are primarily composed of apatite and calcite and formed in a low-energy, anoxic, semi-deep to deep lacustrine environment. They exhibit an average total porosity of 4.84% and an average TOC of 1.99 mg/g. It is 14.7% and 17.8% higher than the clay laminae, and 255.9% and 109.57% higher than the calcareous bioclastic laminae. The pore system is dominated by mesopores and macropores, encompassing multiple pore types including dissolution pores, interparticle pores, interlayer pores, organic matter-hosted pores, and micro-fractures. Notably, a well-connected nanometer-scale pore network developed within fish bone fragments contributes substantially to the storage space. These intervals integrate high organic matter richness with superior reservoir properties, demonstrating typical “source-reservoir integration” characteristics. Their pore structure is synergistically regulated by sedimentary–diagenetic processes, with a core mechanism of primary biogenic pore foundation–late diagenetic dissolution enhancement–micro-fracture connectivity. This study systematically elucidates, for the first time, the reservoir formation mechanism of the phosphatic bioclast-rich laminae in the Lianggaoshan Formation. It confirms their potential as “geological-engineering” dual sweet spots for shale oil and gas exploration, providing a new basis for sweet spot prediction and exploration deployment targeting similar phosphatic bioclastic laminae in the Sichuan Basin and analogous regions. Full article

In recent years, an ion-adsorption type REE deposit has been discovered for the first time in the weathering crust of epimetamorphic rocks in Ningdu County, Jiangxi Province, which provides a new idea for the exploration of ion-adsorption-type REE deposits. However, most previous studies on the ore-forming parent rocks of ion-adsorption-type REE deposits have focused on granites and volcanic rocks, while studies on epimetamorphic rocks remain extremely scarce. In this paper, petrographic analysis of epimetamorphic rocks, LA-ICP-MS U–Pb dating and trace element analysis of zircon and apatite were conducted on the metamorphic tuff from the Kuli Formation in Ningdu County, Jiangxi Province, so as to constrain the formation age and tectonic dynamic setting of the rock mass, investigate the petrogenesis and material source of the rock mass, and reveal the metallogenic potential of the rock mass. The results of zircon and apatite U–Pb dating show that the protolith of the metamorphic tuff from the Kuli Formation formed at ca. 770 Ma, representing a product of mid-Neoproterozoic magmatic activity. The protolith restoration of metamorphic rocks suggests that the protolith of the metamorphic tuff from the Kuli Formation is magmatic rock. The estimated results of zircon Ti thermometry indicate that the magmatic crystallization temperature ranges from 623 to 723 °C, with an average value of approximately 696 °C, and the calculated zircon oxygen fugacity values vary from −18.7 to −9.4, with an average of −13.8, implying that the rock formed under conditions of relatively low temperature and high oxygen fugacity. The correlation diagrams of trace elements and element ratios in zircon and apatite reveal that the magmatic evolution involved extensive fractional crystallization of minerals such as zircon, monazite, apatite, titanite, rutile, and plagioclase during the formation of the rock mass. The discrimination diagrams of trace elements in zircon and apatite demonstrate that the metamorphic tuff from the Kuli Formation was formed in a continental margin arc or arc-related orogenic belt, and the magmatic source is characterized by crust–mantle mixing. Combined with previous research findings on regional tectonic-magmatic activities, it can be concluded that the metamorphic tuff from the Kuli Formation was formed in a tectonic setting of back-arc extension and intra-arc rifting caused by the rollback of the subducting oceanic slab. The upwelling of the asthenospheric mantle induced the partial melting of arc-derived sediments in the continental crust, which was subsequently mixed with mantle-derived magma, ultimately generating the parent magma of the metamorphic tuff. The metamorphic tuff from the Kuli Formation in Ningdu County, Jiangxi Province, has high REE abundance and relatively easily weathered REE mineral assemblages, which can provide sufficient material sources for ion-adsorption REE mineralization and have a great metallogenic potential for ion-adsorption REE deposits. Full article

The Jiaodong Peninsula hosts one of the largest gold provinces in the world. The Xincheng gold deposit, located within the Jiaojia gold metallogenic belt, is the largest deposit in this belt and represents a super-large fractured alteration-type gold deposit hosted in fracture zones with relatively well-preserved conditions. Mineralization and hydrothermal alteration are controlled by the Jiaojia Fault zone and its subsidiary faults. The Jiaojia Fault (JJF) serves as the principal ore-hosting structure of the Xincheng deposit, and its multi-stage activity has governed the mineralization, subsequent modification, and preservation of the deposit. However, the post-mineralization cooling, uplift, and exhumation history of the deposit remains poorly constrained. In this study, zircon and apatite fission-track thermochronology analyses were conducted, and inverse thermal history modeling of apatite was performed to reconstruct the tectonic-metallogenic evolution of the Xincheng gold deposit. The zircon fission-track ages range from 90.0 ± 4.0 to 118.0 ± 5.2 Ma, which are younger than the mineralization age (~120 Ma), indicating that the region experienced widespread cooling during the Late Early Cretaceous. This cooling event was likely related to crustal uplift and exhumation triggered by a transformation of the tectonic regime. The apatite fission-track ages range from 15 ± 1.8 to 38 ± 2.7 Ma, recording the Cenozoic cooling and uplift history after mineralization. The inverse thermal history modeling results show that the post-mineralization cooling process can be divided into three stages. The first stage, from 42 ± 5 to 30 ± 4 Ma, is characterized by rapid cooling, with an average cooling rate of 4.23 °C/Myr. The second stage, from 30 ± 4 to 12 Ma, represents a period of slow cooling, with an average cooling rate of 0.98 °C/Myr. Since 12 Ma, the third stage has been marked by renewed rapid cooling, with an average cooling rate of 4.17 °C/Myr. Variations in cooling rates among different stages reflect adjustments in the regional tectonic stress field and the influence of activity along the JJF. Based on the fission track thermochronological data and a reasonable estimate of the geothermal gradient, the total amount of exhumation since 120 Ma is calculated to be approximately 8.22 km. Integration of these results indicates that the shallow portion of the deposit has undergone a certain degree of erosion; however, the overall preservation conditions remain favorable, and significant exploration potential persists at depth and along strike. This study constrains the post-mineralization cooling and erosion history of the Xincheng gold deposit, reveals the controlling role of multi-stage tectonic activity on deposit preservation, and provides new temporal constraints and a scientific basis for preservation assessment and deep exploration of gold deposits in the Jiaodong Peninsula and in regions with similar tectonic settings. Full article

The exploration of new materials with stable molten calcium–magnesium–aluminum-silicate (CMAS) resistance at elevated temperatures is of great significance to the development of advanced aero-engines. In the present study, Al₂O_3−xGd₂O₃ (x = 5, 10, 20, 30 mol.%) ceramic samples were prepared by the high-temperature solid-state synthesis method. The thermochemical reaction behavior, reaction products, and growth kinetics of the reaction layer for the ceramics with molten CMAS at 1300 °C were investigated. The results reveal that the primary reaction products between Al₂O_3−xGd₂O₃ ceramics and molten CMAS are anorthite (CaAl₂Si₂O₈), gehlenite (Ca₂Al(AlSi)O₇), spinel (MgAl₂O₄), and Gd-apatite (Ca₂Gd₈(SiO₄)₆O₂). In the initial reaction stage, a dense double-layer reaction layer composed of anorthite and spinel is formed at the ceramic/CMAS interface, while its growth rate decreases with increasing reaction time. Increasing the Gd₂O₃ doping content inhibits the growth of the reaction layer and enhances the CMAS penetration resistance of Al₂O_3−xGd₂O₃ ceramics. The mechanism is discussed systematically. Full article

New hard tissue formation helps create a more stable seal in endodontic treatment. To achieve this, a novel class of endodontic sealers containing the pro-osteogenic element, strontium (within a BG), embedded in a polydimethylsiloxane matrix (Sr-PDMS) was produced. The properties of this sealer were compared with a commercially available bioactive endodontic sealer, Guttaflow Bioseal (GFBS). Glass was prepared via the melt quench method and incorporated into the GFBS matrix. Its physical properties were tested against the International Organisation for Standardisation (ISO) 6876. For biocompatibility assessment, dose–response proliferation of OCCM-30 cells was quantified by measuring DNA levels in varying concentrations of exogenous calcium and strontium, in culture media conditioned with the novel BG powder, and in sealer discs of the GFBS and novel Sr-PDMS. Two-way ANOVA followed by one-way ANOVA and the Bonferroni post hoc test were applied to the cell viability data. Both the GFBS and novel Sr-PDMS sealants demonstrated physical properties that met ISO 6876, but Sr-PDMS displayed greater radiopacity (p < 0.05), lower solubility, and increased setting time. Both sealants released ions into the immersion solution, with the additional release of Sr from the novel sealer. GFBS displayed evidence of apatite formation. As expected, high concentrations of BG-conditioned media were cytotoxic, but the levels released by the BG in the Sr-PDMS were not cytotoxic with 1:000 dilution and resulted in significantly increased (p < 0.01) cell proliferation compared to the control group. Full article