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Two novel seco-polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperbenzones A (1) and B (2), were isolated from the roots of Hypericum beanii, together with one known biosynthetic congener 3. Compound 1 incorporates a 6/5/5 ring system with an unprecedented spiro[bicyclo[3.3.0]octane-3,1ʹ-cyclohexane]-2,2ʹ-dione motif. The structures of 1 and 2 were determined by a combination of high resolution electrospray ionization mass spectroscopy (HRESIMS), nuclear magnetic resonance (NMR) spectroscopic analyses, gauge-independent atomic orbital (GIAO) NMR chemical shift calculation with DP4+ analyses, electronic circular dichroism (ECD) calculation, and X-ray diffraction analysis. A 1,2-seco retro-Claisen rearrangement from a bicyclo[3.3.1]nonane PPAP precursor and following chemodivergent radical cascade cyclizations are proposed as the key steps in the biosynthetic pathway to yield compounds 1 and 2. Biological investigations indicated that compounds 1 and 3 could decrease intracellular lipid accumulation in a palmitic acid-induced nonalcoholic steatohepatitis (NASH) cell model.

As main components of magnesia-based refractories, magnesia exhibits excellent properties such as high refractoriness and good basic slag corrosion resistance. However, magnesia produced from CaO containing cryptocrystalline magnesite has limited application owing to the low hydration resistance and poor thermal shock resistance (TSR). This work aimed to investigate the reinforcing effects of microscale monoclinic ZrO2 on free CaO containing magnesia for optimizing mechanical properties, TSR and hydration resistance. The results showed that adding ZrO2 could promote the removal of the open pores, strengthen the interface bonding between various grains and produce crack deflection, which improved flexural strength and fracture toughness. As a result, the TSR of the specimens was enhanced effectively due to increased strength and toughness and reduction in the thermal expansion coefficient. Besides, as the ZrO2 was introduced, hydration resistance of the specimens improved significantly, mainly attributing to the decrease in apparent porosity and elimination of the free CaO by forming CaZrO3 and cubic ZrO2 phases.

The microporous magnesia aggregates show a promising application prospect as tundish lining, due to the excellent thermal insulation. In this study, the effect of nano-sized Al2O3 addition on the corrosion resistance of microporous magnesia aggregates against tundish slag is explored. The results show that the addition of nano-sized Al2O3 deteriorates the slag resistance of microporous magnesia aggregates, which is mainly because that the apparent porosity of aggregates increases with the addition of nano-sized Al2O3. Furthermore, MgO·Al2O3 spinel is formed in situ at the grain boundaries of Al2O3-bearing aggregates and the dissolution of MgO·Al2O3 spinel into molten slag damages the structure of aggregates. For the Al2O3-free microporous magnesia aggregates, as expected, the penetration of high basicity slag (CaO/SiO2 = 9, mass ratio) into refractory is slighter than that of low basicity slag (CaO/SiO2 = 4, mass ratio). But, for the Al2O3-bearing microporous magnesia aggregates, the corrosion of refractory by high basicity slag is severer. This is mainly because that MgO·Al2O3 spinel is more unstable in high basicity slag. Therefore, it is not suitable to add nano-sized Al2O3 for the preparation of microporous magnesia as tundish lining.

Ti3AlC2/Al2O3 composites were synthesized by aluminothermic reduction of TiO2/Al/C and TiO2/Al/TiC. The effects of carbon sources (carbon black and TiC), steps heating-up profile, and Al-excess of raw materials composition on the Ti3AlC2 content in final products were investigated. The results showed that in contrast with carbon black, TiC used as a carbon source is beneficial to the formation of Ti3AlC2 at lower temperatures. However, Ti3AlC2 content in the product with carbon black was improved by the steps heating-up profile and Al-excess, promoting intermediate phases TiAl3 and TiC. Furthermore, the formation mechanisms of Ti3AlC2 with different carbon sources in aluminothermic reaction systems were also elucidated. For the TiO2/Al/C system, Ti3AlC2 is precipitated from the Ti–Al melt at high temperatures via the dissolution-precipitation mechanism, which has slower nucleation but faster growth. In contrast, in the TiO2/Al/TiC system, Ti3AlC2 is mainly growing from the intact TiC grains through the epitaxial nucleation mechanism, which has faster nucleation but lower growth.

Thermal shock resistance is of great importance for MgO–C refractories used in steelmaking process. In this study, calcium magnesium aluminate (CMA) aggregates were selected to replace partially fused magnesia aggregates in MgO–C refractories, and their effects on phase compositions, microstructure, thermal shock resistance and fracture behavior of MgO–C refractories were investigated. The results showed CMA aggregates partly disintegrated, and spinel particles and whiskers were observed together with Al4C3 phase in MgO–C specimens coked at 1400 °C. With the increase in coking temperature up to 1600 °C, CMA aggregates completely disintegrated to generate much liquid phase, which promote the formation of spinel whiskers apart from spinel particles and hexagonal AlN in MgO–C refractories. CMA aggregates containing MgO–C refractories coked at 1400 °C possessed higher thermal shock resistance because CMA aggregates had abundant micro-sized pores and lower thermal expansion coefficient. When reheating up to 1600 °C in coke bed after thermal shocks, they had higher recovery strength index than CMA-free refractories. Furthermore, MgO–C refractories containing CMA showed lower brittleness and better bearing capacity via wedge splitting test.

SiC porous ceramics (SPCs) are key functional medium materials, which are widely applied as porous burners. However, SPCs produced via the polyurethane sponge replica technique usually exhibit a randomly distributed cellular structure, leading to vulnerability and a low combustion efficiency for the porous burners. In this study, SPCs were structurally designed via novel 3D printed resin template technique; this endowed the SPCs with synergistically optimized strength and combustion characteristics. SPCs containing tetrakaidecahedron, octahedron and cubic cells were successfully prepared via SiC slurry coating and sintering in air. The cell parameters determined the strength and combustion properties of the SPCs. The SPCs containing cubic cells exhibited the largest strength and strain, because more struts were present parallel to the loading direction; this is more advantageous for stress bearing compared to those vertical to the loading direction. The tetrakaidecahedron cell facilitated the formation of a disturbance effect within the SPCs to a higher extent than the cubic and octahedron cells, thereby enhancing the heat exchange performance between the fluid and porous framework. Hence, the SPC with tetrakaidecahedron cells exhibited the best combustion properties, which resulted in the highest surface temperature and lowest pollution emission.

Cr-refractories usually contain Cr(III) compounds that can convert into carcinogenic Cr(VI) compounds such as CaCrO4 and Ca4Al6CrO16 under alkaline and oxygen-rich conditions. Literature provides insight into the characteristics, thermal stability, and aqueous solubility of CaCrO4, while there is hardly any data available on Ca4Al6CrO16. The present paper comprehensively studied high-temperature stability and leaching kinetics and other characteristics of Ca4Al6CrO16 by using high-temperature XRD, TG-DSC, XPS, Raman, and TRGS 613. XPS confirmed that chromium in Ca4Al6CrO16 is present in the +6 oxidation state. Ca4Al6CrO16 is thermally stable up to 1500 °C in the air but decomposes in nitrogen above 1258 °C to form the Cr3+-containing phases CaCr2O4 and Ca6Al4Cr2O15. The Ksp of Ca4Al6CrO16 in deionized water is 1.0381 × 10−22, 4.5723 × 10−21 and 2.3489 × 10−20 at 12, 25, and 40 °C, respectively. The leaching process of Ca4Al6CrO16 is chemical reaction controlled, with an apparent activation energy of 58.78 kJ/mol.

h-BN is an ideal substitution candidate for graphite due to its similar crystal structure, better oxidation resistance. In this work, the effect of h-BN on microstructure and comprehensive properties of Al2O3-C refractories are investigated, and the specimen containing 0.5 wt% h-BN (G0.5N0.5) possesses the best comprehensive properties. The addition of h-BN could reduce the diameter of SiC whiskers, which leads to the highest strength of specimen G0.5N0.5 (42.63 ± 3.10 MPa). Moreover, the fracture behavior of the specimens is demonstrated using wedge splitting test. The results show that the specimen G0.5N0.5 possesses the highest crack initiation and propagation resistance, which could be attributed to the collaborative effect of h-BN and SiC whiskers. Noteworthily, the addition h-BN could improve the thermal shock resistance. The specimens containing h-BN possess the higher residual ratio, compared with the specimen containing no h-BN (G1N0), and the specimen G0.5N0.5 shows the highest residual strength (14.12 ± 0.67 MPa). Furthermore, the oxidation resistance could be enhanced with introducing the h-BN.

It is of great importance to understand the thermal properties of MoSe2 films for electronic and optoelectronic applications. In this work, large-area polycrystalline MoSe2 films are prepared using a low-cost, controllable, large-scale, and repeatable chemical vapor deposition method, which facilitates direct device fabrication. Raman spectra and X-ray diffraction patterns indicate a hexagonal (2H) crystal structure of the MoSe2 film. Ellipsometric spectra analysis indicates that the optical band gap of the MoSe2 film is estimated to be ∼1.23 eV. From the analysis of the temperature-dependent and laser-power-dependent Raman spectra, the thermal conductivity of the suspended MoSe2 films is found to be ∼28.48 W/(m·K) at room temperature. The results can provide useful guidance for an effective thermal management of large-area polycrystalline MoSe2-based electronic and optoelectronic devices.

Low-carbon MgO–C refractories are facing great challenges with severe thermal shock and slag corrosion in service. Here, a new approach, based on the incorporation of nano-sized ZrO2–Al2O3 composite powder, is proposed to enhance the thermal shock resistance and slag resistance of such refractories in this work. The results showed that addition of ZrO2–Al2O3 composite powder was helpful for improving their comprehensive performances. Particularly, the thermal shock resistance of the specimen containing 0.5 wt% composite powder was enhanced significantly which was related to the transformation toughening of zirconia and in-situ formation of more spinel phases in the matrix; also, the slag resistance of the corresponding specimen was significantly improved, which was attributed to the optimization of pore structure and formation of much thicker MgO dense layer.

The recycling of solid waste is a win-win solution for humans and nature. For this purpose, magnesite tailings and silicon kerf waste were employed to prepare MgO–Mg2SiO4 composite ceramics by solid-state reaction synthesis in the present work. Then, effects of sintering temperature and raw material ratio on as-prepared ceramics were systematically studied. As-prepared ceramics showed improvement in their relative density (from 47.55%–68.12% to 90.96%–95.25%) and cold compressive strength (from 7.34–118.66 MPa to 303.39–546.65 MPa) with the increase in sintering temperature from 1300 to 1600 °C. In addition, it was found that Si promoted synthesis process of Mg2SiO4 phase through transient liquid phase sintering and Fe2O3 accelerated sintering process through activation sintering. Consequently, the presence of Mg2SiO4 phase effectively improved the density and strength of MgO–Mg2SiO4 composite ceramic, while reducing its thermal conductivity. This work provides a potential reutilization strategy for magnesite tailings, and as-prepared products are expected to be applied in fields of construction, metallurgy, and chemical industry.

The mechanical properties and oxidation resistance of the Al2O3-C refractories are of critical importance for iron and steel making processes. However, the evaporation of antioxidants related phases such as Al(g), Si(g), and SiO(g) would deteriorate these properties, especially during high-temperature treatment/application. Therefore, in the present work, a small amount of Ti3AlC2 compared with Al was introduced to overcome these problems. The phase compositions, microstructures, mechanical properties, and oxidation resistance of Ti3AlC2 containing refractories were investigated. The partial oxidation of Ti3AlC2 led to inherited lamellar structures such as Ti3Al1-xC2, TiC, and granular Al2TiO5 phases. The controlled oxidation of Ti3AlC2 and its volume expansion contributed to the compact-structure, thereby limiting the escape of Si and SiO vapors at high temperatures. Consequently, the mechanical properties and oxidation resistance of Ti3AlC2 containing Al2O3-C refractories treated at 1600 ℃ were improved.

Fused silica (SiO2) ceramic crucibles with α-Si3N4 coating are commonly used for smelting photovoltaic silicon (Si). However, SiO2 ceramics will inevitably undergo crystallization and large volume change during the high-temperature service, which will lead to crucible cracking and deteriorate the quality and yield of the Si ingot. In this work, α-Si3N4/SiO2 ceramics are fabricated by introducing α-Si3N4 into SiO2 ceramics to inhibit crystallization. The results show that the introduction of α-Si3N4 can effectively inhibit crystallization of SiO2 ceramics at temperature higher than 1450 °C. Only 5 wt% cristobalite form in SiO2 ceramic with 20 wt% α-Si3N4 (heated at 1550 °C for 30min). The crystallization activation energy of SiO2 ceramic containing 20 wt% α-Si3N4 increases by 2.27 times to 931.2kJ/mol compared with that of pure SiO2 ceramic (409.6kJ/mol). The inhibition crystallization effect and increased activation energy derive from the in-situ formation of O–Si–N chemical bond and physical isolation of SiO2 particles by α-Si3N4 powders.

The pseudo-ternary Al2O3–CaO–Cr2O3 system is of great interest due to various pyrometallurgical applications. However, Cr3+ might be oxidized into toxic and carcinogenic Cr6+ during service, causing harm to humans and the environment. So, doping an adequate amount of SiO2 could suppress the generation of Cr6+. In this experiment, the Al2O3–CaO–Cr2O3 ternary system was doped with different amounts of SiO2 (0–47 wt%) and heat-treated at 1400 °C in the air atmosphere. The reaction mechanism and the phase evolution process were studied by implementing XRD, SEM-EDS, leaching tests, XPS, and associated software. In the Al2O3–CaO–Cr2O3 system under the air atmosphere, chromium primarily exists as a Cr3+ compound CaAl2Cr23+O7 and a Cr6+ compound Ca4Al6Cr6+O16 as a secondary phase. The Cr6+ leaching process was diffusion-controlled and more effective at elevated temperatures. However, Ca4Al6Cr6+O16 disappeared with the addition of SiO2. With the increase of SiO2 content, Cr2O3 tends to be in the Cr3+ form with gehlenite phase (Ca2(Al, Cr)2SiO7) and anorthite phase (Ca(Al, Cr)2Si2O8), thereby inhibiting the Cr6+. Nevertheless, the investigated compositions in the quaternary systems do not exhibit Cr6+ in the air atmosphere at 1400 °C.

It is believed that the formation of hydration phase, MgO-SiO2-H2O (M-S-H), contributes to good workability and reliable comprehensive properties for magnesia based castables. In order to stimulate the formation of M-S-H in magnesia based castables and understand the minimum introduction of microslica amount, wet milling process was used to promote the dissolution of MgO and SiO2 in this work. The slurry containing different content of microsilica with wet milling technology and the castables with/without wet milling slurry were prepared. The effects of microsilica content on the formation of hydration phases were analyzed by XRD, FT-IR and TG/DSC and the properties of magnesia based castables were evaluated by explosion resistance, CMOR, HMOR and so on. The results showed that the formation of M-S-H was accelerated because of the dissolution of Mg2+ and HSiO3− in wet milling process. Higher amount of M-S-H led to a tight bonding in the early stage, and a denser structure after firing at high temperature due to the limited formation of brucite and in-situ formation of evenly distributed forsterite phase. In addition, much higher HMOR were obtained when less microsilica was added, attributing to the suppressed formation of low-melting-point liquid. Therefore, 2–3 wt% microsilica addition was recommended in this process.

In current work, effect of different carbon sources on densification and mechanical properties of WC ceramics was studied by using a new type of oscillatory pressure sintering technique. It was found that addition of 0.3 wt% carbon contributed not only to promoting densification of WC ceramics but also to inhibiting formation of W2C phase, thus considerably enhancing mechanical properties of such ceramics. The highest relative density of 99.76%, corresponding hardness of 26.31 GPa and fracture toughness of 6.85 MPa·m1/2 were obtained for WC ceramics with graphite oxide nanosheets as carbon source; also, crack deflection, crack bridging and pulling-out of graphite oxide nanosheets were main toughening mechanisms of such ceramics. It was suggested that WC ceramics with high performances can be prepared by combination of oscillatory pressure sintering and carbon addition.

Al2O3–CaO–Cr2O3 castables are required for various furnaces linings due to their excellent corrosion resistance. However, toxic and water-soluble Cr(VI) could be generated in these linings during service. In this study Al2O3–CaO–Cr2O3 castables were prepared and heated at 300–1500 °C in air and coke bed to simulate actual service conditions. The formations of various phases were investigated by XRD and SEM-EDS. The Cr(VI) compounds CaCrO4 and Ca4Al6CrO16 formed in air at 300–900 °C and 900–1300 °C respectively, while C12A7 and CA2 were generated rather than forming Cr(VI) compounds in coke bed at 700–1300 °C. However, at 1500 °C, nearly all the chromium existed in the form of (Al1-xCrx)2O3 solid solution in both atmosphere. As a result, the specimens treated in air contained 185.0–1697.8 mg/kg of Cr(VI) at 500–1300 °C but only 17.2 mg/kg of Cr(VI) at 1500 °C, whereas specimens treated in coke bed exhibited extremely low Cr(VI) concentration in the whole temperature range studied. Moreover, in coke bed, the mutual diffusion between Cr2O3 and Al2O3 was suppressed and a trace of Cr2O3 would even be reduced to form chromium-containing carbides on its surface, which would hindered the sintering process and hence lower the density as well as strength of the castables.

The dearth of appropriate electrocatalysts for stable anodic water splitting, oxygen evolution reaction (OER), in acid has given rise to concerted efforts toward making iridium-based high aspect ratio nanomaterials, as iridium and its higher valent oxides have been shown time and again to exhibit the most optimal balance between activity and durability. Here, we show a dealloying strategy to synthesize free-standing 3D, oxide skinned nanoporous Ir electrocatalysts (np-Ir) with demonstrated enhanced activity and durability in comparison to more traditional IrOx nanoparticulate catalysts. The metallic core and absence of any binder/support result in low electrode and charge transfer resistance, ultimately giving rise to lower OER overpotentials and improved activity.

Obtaining a stable Cr3+ phase at higher temperatures in the presence of hydraulic calcium aluminates (the phases found in calcium aluminate cement, CAC) in the Al2O3–CaO–Cr2O3 system remains a significant challenge in many application areas, as the formation of toxic, carcinogenic, and water-soluble Cr6+ compounds often occur. To address the issue, recently, we synthesized a high-temperature stable Cr3+ ternary compound (CaAl2Cr2O7) with space group P3 (143). In the present work, we investigated the formation-stability of CaAl2Cr2O7 with in-situ calcium aluminate phases at 1500 °C under the CO2 atmosphere in the Al2O3–CaO–Cr2O3 system through solid-oxide reactions route varying Cr2O3 content (at constant Al2O3:CaO ratio). It co-existed with hydraulic calcium aluminates and other phases over the full investigated composition range of 2.76–68.3 mol% Cr2O3 (5–80 wt%). Apart from CAC phases (CaAl2O4, CaAl4O7), major Cr3+-phases are CaAl2Cr2O7 and (Al,Cr)2O3 while (α,β)-CaCr2O4 and Ca(Al,Cr)12O19 formed as minor phases. At a constant Al2O3:CaO ratio of 5.6:4.4 mol% (7:3 wt%), the formation of the CaAl2Cr2O7 phase increases with Cr2O3 content (up to the investigated composition of 26.43 mol%) and then decreases gradually. The solid solubility of Al and Cr in the CaAl2Cr2O7 phase limited over a narrow range, and presumably dependent more on heat treatment condition rather than composition as reflected from the lattice parameter calculations. Though XRD revealed the presence of only Cr3+-phases in the partial CO2 atmosphere, however, traces of Cr6+ could be detected using XPS and leaching tests. However, leachable Cr6+ content (0.095–1.252 mg/L) were much below the United States Environmental Protection Agency (US-EPA) permissible limit of 5 mg/L. The formation mechanism of the CaAl2Cr2O7 and other phases with plausible reactions were also discussed.

Pd/CeO2 catalysts show superior catalytic performance owing to their optimal cycling activity and stability. In this study, single-atom Pd and eight-atom Pd nanoparticle clusters were supported on the surface of CeO2(110) to investigate the effect of loaded-metal size on the catalytic performance of the Pd–CeO2 system for CO2 reduction. We investigated the CO2 reduction reaction (CRR) that produces C1 products (CO, HCOOH, CH3OH, and CH4) on Pd8/CeO2 and Pd/CeO2 by density functional theory. The structures, CO2 adsorption configurations, and CO2 reduction mechanisms of these two electrocatalysts were systematically studied. Subsequently, different reduction pathways on Pd8/CeO2 and Pd/CeO2 were investigated to identify the optimal reaction pathway for further assessment. The results showed that both of these catalysts are more selective towards the production of CH3OH than CH4. Moreover, compared to Pd/CeO2 and Pd4/CeO2 (from a previously reported study) the production of CH3OH via the CRR on Pd8/CeO2 exhibited the lowest limiting potential. These results demonstrate the superiority of Pd8/CeO2 as an electrocatalyst for the electrochemical reduction of CO2 to CH3OH.

Graphical abstract, Highlights • Candidate genomic biomarkers were revealed for PARPis from genetic interactions. • Gain-of-function mutation of EGFR induced resistance to PARP inhibitors. • Lung cancer may benefit from combination of PARP inhibitor and EGFR inhibitor. • Gene set of biomarkers for PARPis contributes to the prognosis of cancer patients., Poly (ADPribose) polymerase inhibitors (PARPis) are clinically approved drugs designed according to the concept of synthetic lethality (SL) interaction. It is crucial to expand the scale of patients who can benefit from PARPis, and overcome drug resistance associated with it. Genetic interactions (GIs) include SL and synthetic viability (SV) that participate in drug response in cancer cells. Based on the hypothesis that mutated genes with SL or SV interactions with PARP1/2/3 are potential sensitive or resistant PARPis biomarkers, respectively, we developed a novel computational method to identify them. We analyzed fitness variation of cell lines to identify PARP1/2/3-related GIs according to CRISPR/Cas9 and RNA interference functional screens. Potential resistant/sensitive mutated genes were identified using pharmacogenomic datasets. We identified 41 candidate resistant and 130 candidate sensitive PARPi-response related genes, and observed that EGFR with gain-of-function mutation induced PARPi resistance, and predicted a combination therapy with PARP inhibitor (veliparib) and EGFR inhibitor (erlotinib) for lung cancer. We also revealed that a resistant gene set (TNN, PLEC, and TRIP12) in lower grade glioma and a sensitive gene set (BRCA2, TOP3A, and ASCC3) in ovarian cancer, which were associated with prognosis. Thus, cancer genome-derived GIs provide new insights for identifying PARPi biomarkers and a new avenue for precision therapeutics.

Magnesia-carbon (MgO–C) refractory is considered as the most crucial lining material in steelmaking furnaces. To provide reference for producing high performance MgO–C refractory containing different carbon contents, the microstructure, mechanical strength, thermal shock resistance and thermal properties of this material with 1–18 wt% flake graphite were studied systematically in this work. The results showed that carbon content had small effect on microstructural evolution of MgO–C refractory after high temperature treatment, mainly MgAl2O4 particles, Al4C3 whiskers and plate-/whisker-shaped AlN formed in the matrix of all specimens. As carbon content added increased gradually, fracture strength of specimens exhibited a reduced tendency whereas the corresponding fracture displacements became higher and higher owing mainly to good sliding ability of flake graphite. Furthermore, the increase in carbon content reduced thermal expansion rate of specimens and correspondingly increased thermal conductivity, consequently contributing to enhanced resistance to thermal shock of MgO–C refractory.

Magnetite is typomorphic, and its crystal textures and chemical fingerprint form unique signatures that can be used to determine sediment provenance. Determination of the provenance of sediments in the upper Yangtze River is critical for understanding its evolution and the uplift of the Tibetan Plateau. In this study, petrographic analysis and electron-probe microanalysis (EPMA) of 800 detrital magnetite grains were performed to differentiate the provenance of sediments within the mainstream and major tributaries of the upper Yangtze River catchment. Chemical analyses show that the elemental composition of magnetite grains shows pronounced variations among the different sections of the mainstream and tributaries. Based on the observed chemical fingerprints, we infer that the source rocks control the elemental composition of magnetite grains. The magnetite contribution is closely related to the tectonics, climate, and erosion of parent rocks within different drainage basins. Magnetite from the trunk stream of the Jinsha River is found to be a significant contributor to the upper Yangtze River. Magnetite grains of the upper Jinsha River are primarily derived from source areas composed of silicic plutonic rocks and ophiolite lithologies that crop out on the SE Tibetan Plateau. Magnetite grains within the sands of the lower Jinshajiang sediments are characterized by high concentrations of Ti, Mg, Cr, Al, and Mn, and are derived from the widely distributed Emeishan flood basalts and Pan-Xi layered basic–ultrabasic igneous rocks. This source is also a major contributor of magnetite to the upper Yangtze River, and the parent rock distributed in this region is of typomorphic significance to the development of the Yangtze River. The origin of magnetite grains in the tributaries depends on the parent rocks distributed in their catchments. In summary, the presence of detrital magnetite grains provides valuable information for discriminating the provenance of sediments in the upper Yangtze River drainage basins.

The Al2O3-CaO-Cr2O3 systems are widely regarded as highly corrosion-resistant refractory castables, but leading a Cr(VI) problem after service. In the present paper, different contents (0–13.33 wt%) of MS (micro-silica) were added to the castables’ matrix system and heat-treated at 110–1500 °C in an air atmosphere. XRD, SEM-EDS, and leaching tests were done to study the influence of MS content on the formation, inhibition, and leaching kinetics of Cr(VI) phases. The formation of silicate phases is more favorable over Cr(VI) phases at higher temperatures and lower CaO/SiO2 ratios. With increasing MS content, the Cr(VI) compounds decrease gradually until disappearing at the C/S ratio of 0.36. Simultaneously, calcium aluminum garnet, gehlenite, and anorthite phases were formed gradually. When the MS content reached 13.33% (C/S = 0.36%), the total leachable Cr(VI) is decreased by 70% at 700 °C and 100% at 1100 °C respectively. The leaching kinetics experiment indicated that the Cr(VI) leaching process was governed by diffusion via product layers.

Calcium aluminate cement-bonded Al2O3-SiC-C castables are widely used in practice due to sufficient initial strength and operability. However, a high amount of cement leads to deteriorated high-temperature properties due to the formation of low-melting-point phases. The present work aimed at optimizing the comprehensive properties of the ultra-low cement-bonded Al2O3-SiC-C castables with the introduction of high purity synthetic zeolite. The influences of additives on the properties of castables and the hydration behavior of cement were investigated. The results showed that zeolite had the following advantages: it promoted the hydration of cement through enhancing the physical absorption and potential chemical complexation of Ca2+ and eventually induced growth of the predominant plate-like hydrates (C2AH8) at 25 ℃. The formation of more C2AH8 was beneficial to improve the green strength even with less cement. The substitution of cement with 0.5 wt.% synthetic zeolite contributed to improved high-temperature properties by reducing CaO content.

Tungsten carbide ceramics were fabricated by a novel oscillatory pressure sintering process and the influence of sintering temperature on the microstructure and mechanical properties of tungsten carbide ceramics was investigated. It was found that tungsten carbide would decarbonize to form W2C under high temperature environment. As the sintering temperature increased, the density and hardness of tungsten carbide ceramics increased apparently, and the growth of tungsten carbide grains became more obvious. The samples fabricated by oscillatory pressure sintering exhibited superior mechanical properties in comparison with some published data obtained by other pressure-assisted sintering methods. The optimum sintering temperature for tungsten carbide ceramics under oscillatory pressure was considered to be 1900 °C. Flexural strength, hardness and fracture toughness of the corresponding sample prepared at this temperature were found to be 1014 MPa, 26.98 GPa and 5.91 MPa·m1/2, respectively.

Multiresponsive nanoprobes are highly desirable for low background and highly sensitive imaging in biomedical applications. Herein, we design a glutathione (GSH)/pH dual-responsive nanoprobe capable of both fluorescence imaging in cells and 19F magnetic resonance imaging (19F MRI) in deep tissue, by encapsulating manganese oleate (Mn(OA)2) on the surface of fluorinated fluorescent quantum dots (F-ZnS:Mn2+). In this approach, Mn(OA)2 serves as an efficient quencher of both fluorescence and 19F MRI signal. Both the fluorescence and 19F MRI signal can be turned on by introducing glutathione (GSH) that breaks up the Mn-O bonds within Mn(OA)2 under weak acidity conditions (e.g., pH 6.0). The imaging results in cells and mice suggest that this novel strategy can offer a promising nanoprobe for turn-on fluorescence/19F MRI dual-modal tumor imaging.

Celastrol has recently been identified as a prospective new treatment for obesity and several metabolic complications. However, the effect of Celastrol in osteoporosis (OP) remains unknown. In this study, we demonstrated that Celastrol promotes osteoblast differentiation and prevents adipocyte differentiation in bone marrow mesenchymal stem cells (BM-MSCs) in vitro. Mechanistically, Celastrol was able to control the differentiation of BM-MSCs by stimulating PGC-1α signaling. Moreover, administration of Celastrol could alleviate bone loss and bone marrow adipose tissue (MAT) accumulation in ovariectomized (OVX) mice and aged mice. Together, these results recommended that Celastrol could regulate BM-MSCs fate and bone-fat balance in OP and skeletal aging by stimulating PGC-1α, which might act as a possible therapeutic target for OP and for the prevention of skeletal aging.

To evaluate the effect of a nitrification inhibitor on reducing N2O emissions from saline soils, we undertook a field plot experiment with three salinity levels (non-saline, NS = 0.21 dS m−1; low saline, LS = 1.02 dS m−1; and high saline, HS = 5.23 dS m−1), factorially combined with two nitrification inhibitor treatments (with and without DMPP (3,4-dimethylpyrazole phosphate)). The low saline soil had the highest N2O flux peak and its cumulative N2O emissions were 2.2-fold those of the non-saline soil and 3.1-fold those of the high saline soil. Low salinity strongly inhibited nitrite oxidation and only slightly inhibited ammonia oxidation, which resulted in a high accumulation of NO2−-N and high N2O emissions. The nitrification inhibitor DMPP reduced cumulative N2O emissions (p

SiC reticulated porous ceramics (RPCs), as the key functional components, are widely applied in field of molten-metal filtration. However, the hollow struts with triangular tips caused by burnt out of polymer foam reduced the strength of SiC RPCs, which limited their engineering application. Aiming to reveal the effects of template strut morphology on the mechanical performance of SiC RPCs, templates with triangular, square and circular cross sections were designed by additive manufacturing. Subsequently, SiC RPCs with varied strut structures were prepared by slurry immersion, followed by sintering at elevated temperature. The blunt of template strut improved the mechanical property of SiC RPCs, samples with circular hollow struts showed the highest crushing strength and strain than that of triangular and square hollow struts. From the results of simulation calculation, triangular hollow struts led to the significant stress concentration in the connection of struts and their middle parts, while the smaller stress uniformly distributed in the whole SiC skeleton as hollow struts became circle, thereby the improved mechanical properties were obtained in SiC RPCs.

Perfluorosulfonic acid (PFSA)-based ionomers, most notably Nafion, provide the ionic connection between catalyst particles and solid polymer ion conducting membrane separators in polymer electrolyt...

Magnesia-chrome bricks are commonly used as the lining of smelters in copper and lead industry because of their resistance against the thermal, mechanical and chemical loads in the pyrometallurgical production process. In fact, the pyrometallurgical production process of lead-copper matte is generally a reducing process with plenty of coke and iron fillings as reducing agent, which implies that the magnesia-chrome bricks service in stronger reducing atmosphere. In this work, the microstructure, mechanical properties and slag resistance of such materials were investigated in reducing atmosphere to simulate the influence of the atmosphere on the properties of magnesia-chrome refractories. The results show that obvious increase in porosity and decrease in strength occurred to the magnesia-chrome samples after treating in reducing atmosphere. This is related to the structural damage of samples, in which Fe3+/Fe2+ within spinel (Mg, Fe)(Cr, Al, Fe)2O4 were partly reduced to metallic Fe under reducing atmosphere. Consequently, the slag penetrated much easily into the matrix of the samples. Moreover, the slag corrosion also aggravated due to the aggressive FeO in slag and the formation of magnesiowustite in the penetration layer. Nevertheless, the high melt phases of spinel and forsterite were formed when the slag corrosion test was conducted in air atmosphere, thereby preventing further slag corrosion and penetration.

The preparation of solar grade silicon (Si) is popularly carried out in silica (SiO2) crucible containing porous α-Si3N4 coating, in which poorly wetting SiO2 film around α-Si3N4 particles act as barrier for Si infiltration. The present investigation studies the influence of oxygen (O) content in coating on wettability and infiltration for Si/α-Si3N4/SiO2 ternary system. The amorphous SiO2 film surrounding Si3N4 particles is firstly synthesized by pre-oxidizing coating in air, and the O content is controlled by adjusting pre-oxidizing temperature and holding time. In this work, dynamic wetting behavior of Si drop on coating containing various content of O is investigated using the sessile drop method. Meanwhile, via microstructural analysis, infiltration under the drop and infiltration beyond the drop (including infiltration on coating surface and under coating surface) are distinguished on coatings with different O content. Finally, wettability transformation (from wetting to non-wetting) is analyzed; mechanism of infiltration resistance for O in coating is interpreted by analytical model.

As the key component for porous media burner, the sufficient strength of SiC reticulated porous ceramics (RPCs) is necessary due to the scour of hot flue gas. However, SiC RPCs prepared with template replica method often exhibited serious oxidation and low strength when the foam was burnt out. In the present work, a sol-coated Al powder with high hydration resistance was introduced into the silicon carbide slurry to promote mullite formation in SiC skeleton, meanwhile reduce the SiC oxidation ratio of sample during the heat treatment. Firstly, the silica-sol coated Al with uniform silica-sol was successfully prepared via dip coating to improve the ability of hydration resistance of Al powder. Furthermore, sol-coated Al with spherical morphology improved rheological properties of silicon carbide slurry, including viscosity and rheological behavior. In addition, the evolution mechanism of sol-coated Al in SiC RPCs was revealed. The AlO2(g) and AlO(g) was first formed in the system, thus significantly reducing the SiC oxidation ratio in SiC RPC. The partial pressure of AlO(g) increased with the sintering temperature, the needle-shaped mullite formed at 1300 ○C when it dissolved in the microsilica, while lumpy mullite formed as SiC was the silica source in SiC RPCs. The addition of sol-coated Al was beneficial to optimize the microstructure of SiC skeleton, resulting in higher compressive strength of SiC RPCs.

Polymer electrolyte membrane fuel cell (PEMFC) electrodes with a 0.07 mgPt cm–2 Pt/Vulcan electrocatalyst loading, containing only a sulfonated poly(ionic liquid) block copolymer (SPILBCP) ionomer,...

The poor cycle stability and reversibility seriously hinder the widespread application of SnO2 materials as anodes for lithium-ion batteries (LIBs). A novel sandwich-architecture composite of Si-do...

High-valent transition metal or main group complex mediated σ-bond metathesis plays an important role in the activation of covalent H–E bonds. However, its involvement in the activation of C–C bond...

Hydrogen peroxide (H2O2) synthesis by electrochemical oxygen reduction reaction has attracted great attention as a green substitute for anthraquinone process. However, low oxygen utilization efficiency (, H2O2 electrosynthesis has garnered great attention as a green alternative to the anthraquinone process. Here the authors propose a cost-effective cathode to greatly improve the O2 diffusion coefficient, resulting in a high H2O2 production without the need for aeration.

Hot carriers (electrons and holes) generated from the decay of localized surface plasmon resonances can take a major role in catalytic reactions on metal nanoparticles. By obtaining surface enhanced Raman scattering (SERS) spectra of p-aminothiophenol as product of the reduction of p-nitrothiophenol by hot electrons, different catalytic activity is revealed here for nanoparticles of silver, gold, and copper. As a main finding, a series of different ligands, comprising halide and non-halide species, are found to enhance product formation in the reduction reaction on nanoparticles of all three metals. A comparison with the standard electrode potentials of the metals with and without the ligands and SERS data obtained at different electrode potential indicate that the higher catalytic activity can be associated with a higher Fermi level, thereby resulting in an improved efficiency of hot carrier generation. The concept of such a ligand-enhanced hot electron reduction provides a way to make light-to-chemical energy conversion more efficient due to improved electron harvesting.

Al2O3-CaO-Cr2O3 castables are used in various furnaces due to excellent corrosion resistance and sufficient early strength, but toxic Cr(VI) generation during service remains a concern. Here, we investigated the relative reactivity of analogous Cr(III) phases such as Cr2O3, (Al1−xCrx)2O3 and in situ Cr(III) solid solution with the calcium aluminate cement under an oxidizing atmosphere at various temperatures. The aim is to comprehend the relative Cr(VI) generation in the low-cement castables (Al2O3-CaO-Cr2O3-O2 system) and achieve an environment-friendly application. The solid-state reactions and Cr(VI) formation were investigated using powder XRD, SEM, and leaching tests. Compared to Cr2O3, the stability of (Al1−xCrx)2O3 against CAC was much higher, which improved gradually with the concentration of Al2O3 in (Al1−xCrx)2O3. The substitution of Cr2O3 with (Al1−xCrx)2O3 in the Al2O3-CaO-Cr2O3 castables could completely inhibit the formation of Cr(VI) compound CaCrO4 at 500–1100 °C and could drastically suppress Ca4Al6CrO16 generation at 900 to 1300 °C. The Cr(VI) reduction amounting up to 98.1% could be achieved by replacing Cr2O3 with (Al1−xCrx)2O3 solid solution. However, in situ stabilized Cr(III) phases as a mixture of (Al1−xCrx)2O3 and Ca(Al12−xCrx)O19 solid solution hardly reveal any reoxidation. Moreover, the CA6 was much more stable than CA and CA2, and it did not participate in any chemical reaction with (Al1−xCrx)2O3 solid solution.

Soil nitrous oxide (N2O) is an important source of greenhouse gas contributing to climate change. Many processes produce N2O in soils and the production rate of each process is affected variably by climatic-edaphic factors, making the soil-to-atmosphere N2O flux extremely dynamic. Experimental approaches, including natural and enriched isotopic methods, have been developed to separate and quantify the N2O production from different processes. However, these methods are often costly or difficult to conduct, hampering their widely applications. This study aimed to develop a mechanistic model quantifying the soil N2O production from nitrifier nitrification (NN), nitrifier denitrification (ND), and heterotrophic denitrification (HD), which are considered as the most important biological contributors, and to investigate how climatic-edaphic factors affect individual processes as well as total N2O production rates. The developed model demonstrated its robustness and capability by reliably reproducing N2O productions from the three individual processes of NN, ND, and HD under different moisture contents and oxygen concentrations. The model simulations unraveled how environmental conditions and soil properties controlled the total N2O production rate by regulating individual rates variably. Therefore, the mechanistic model is able to potentially elucidate the large spatiotemporal variances of in-situ soil N2O flux and improve the assessment of soil N2O emission at regional and global scales.