Search Results (9,445)

To address the challenge of low nitrogen removal efficiency, particularly the difficulty in meeting total nitrogen (TN) discharge standards during low-temperature seasons and intermittent emission modes in conventional aquaculture wastewater treatment, this study proposed the novel application of bioretention systems. Biochar and sponge iron were used as fillers to construct three bioretention systems: biochar-based (B-BS), sponge iron-based (SI-BS), and a composite system (SIB-BS), for evaluating their nitrogen removal performance for aquaculture wastewater treatment. Experimental results demonstrated that under intermittent flooding conditions at 8.0–13.0 °C and increasing TN loading (9.48 mg/L–31.13 mg/L), SIB-BS maintained stable TN removal (79.7–86.7%), outperforming B-BS and SI-BS (p < 0.05). Under continuous inflow (influent TN = 8.4 ± 0.5 mg/L) at 8.0–13.0 °C, SIB-BS achieved significantly lower effluent TN (2.57 ± 1.5 mg/L) than B-BS (5.6 ± 1.6 mg/L) and SI-BS (5.0 ± 1.5 mg/L) (p < 0.05). Meanwhile, when the temperature ranged from 8.0 to 26.3 °C, SIB-BS exhibited a more stable and efficient denitrification ability. Mechanistic investigations revealed that coupling biochar with sponge iron promoted denitrifying microbial activity and enhanced the functional potential for nitrogen transformation (p < 0.05). Specifically, biochar provided porous attachment sites and improved mass transfer, while sponge iron supplied readily available Fe²⁺ as an electron donor; their combination buffered iron oxidation and facilitated Fe²⁺-mediated electron transfer. At low temperature, SIB-BS further stimulated extracellular polymeric substances (EPS) secretion, strengthened biofilm stability without causing blockage, and improved the protective interactions between fillers, thereby increasing metabolic efficiency and sustaining TN removal under variable loading. This study provided a technical reference for the efficient denitrification of aquaculture wastewater. Full article

The six platinum group elements (PGE) are among the rarest elements in the upper continental crust of the earth. Higher values of PGE have been detected in the upper mantle and in chondrite meteorites. The PGE are siderophile and chalcophile elements and are divided into the following: (1) the Ir subgroup (IPGE) = Os, Ir, and Ru and (2) the Pd subgroup (PPGE) = Rh, Pt, and Pd. The IPGE are more refractory and less chalcophile than the PPGE. High concentrations of PGE led, in rare cases, to the formation of mineral deposits. The PGE are carried in discrete phases, the platinum group minerals (PGM), and are included as trace elements into the structure of base metal sulphides (BM), such as pentlandite, chalcopyrite, pyrite, and pyrrhotite. Similarly to PGE, the PGM are also divided into two main groups, i.e., IPGM composed of Os, Ir, and Ru and PPGM containing Rh, Pt, and Pd. The PGM occur both in mafic and ultramafic rocks and are mainly hosted in stratiform reefs, sulphide-rich lenses, and placer deposits. Presently, there are only 169 valid PGM that represent about 2.7% of all 6176 minerals discovered so far. However, 496 PGM are listed among the valid species that have not yet been officially accepted, while a further 641 are considered as invalid or discredited species. The main reason for the incomplete characterization of PGM resides in their mode of occurrence, i.e., as grains in composite aggregates of a few microns in size, which makes it difficult to determine their crystallography. Among the PGM officially accepted by the IMA, only 13 (8%) were discovered before 1958, the year when the IMA was established. The highest number of PGM was discovered between 1970 and 1979, and 99 PGM have been accepted from 1980 until now. Of the 169 PGM accepted by the IMA, 44% are named in honour of a person, typically a scientist or geologist, and 31% are named after their discovery localities. The nomenclature of 25% of the PGM is based on their chemical composition and/or their physical properties. PGM have been discovered in 25 countries throughout the world, with 64 from Russia, 17 from Canada and South Africa (each), 15 from China, 12 from the USA, 8 from Brazil, 6 from Japan, 5 from Congo, 3 from Finland and Germany (each), 2 from the Dominican Republic, Greenland, Malaysia, and Papua New Guinea each, and only 1 from Argentine, Australia, Bulgaria, Colombia, Czech Republic, England, Ethiopia, Guyana, Mexico, Serbia, and Tanzania each. Most PGM phases contain Pd (82 phases, 48% of all accepted PGM), followed, in decreasing order of abundances, by those of Pt 35 phases (21%), Rh 23 phases (14%), Ir 18 phases (11%), Ru 7 phases (4%), and Os 4 phases (2%). The six PGE forming the PGM are bonded to other elements such as Fe, Ni, Cu, S, As, Te, Bi, Sb, Se, Sn, Hg, Ag, Zn, Si, Pb, Ge, In, Mo, and O. Thirty-two percent of the 169 valid PGM crystallize in the cubic system, 17% are orthorhombic, 16% hexagonal, 14% tetragonal, 11% trigonal, 3% monoclinic, and only 1% triclinic. Some PGM are members of a solid-solution series, which may be complete or contain a miscibility gap, providing information concerning the chemical and physical environment in which the mineral was formed. The refractory IPGM precipitate principally in primitive, high-temperature, mantle-hosted rocks such as podiform and layered chromitites. Being more chalcophile, PPGE are preferentially collected and concentrated in an immiscible sulphide liquid, and, under appropriate conditions, the PPGM can precipitate in a thermal range of about 900–300 °C in the presence of fluids and a progressive increase of oxygen fugacity (fO₂). Thus, a great number of Pt and Pd minerals have been described in Ni-Cu sulphide deposits. Two main genetic models have been proposed for the formation of PGM nuggets: (1) Detrital PGM represent magmatic grains that were mechanically liberated from their primary source by weathering and erosion with or without minor alteration processes, and (2) PGM reprecipitated in the supergene environment through a complex process that comprises solubility, the leaching of PGE from the primary PGM, and variation in Eh-pH and microbial activity. These two models do not exclude each other, and alluvial deposits may contain contributions from both processes. Full article

KRAS alterations are a hallmark of pancreatic ductal adenocarcinoma (PDAC) found in >90% of tumors. This review examines the historical evolution of the understanding of RAS and its central role in PDAC biology. We summarize the various downstream effectors, feedback loops, and resistance mechanisms that play a pivotal role in PDAC oncogenesis. Our review explores the early development of covalent inhibitors of KRAS G12C and efforts at specific inhibition of other codons and newer approaches of targeted protein degradation. We subsequently summarize the development of panRAS inhibitors and allosteric and switch-region targeting before focusing on rational therapeutic blockade of crosstalk and upstream signaling, with attention to synthetic lethality approaches transitioning from preclinical to early-phase in-human clinical trials. This review elaborates on ongoing KRAS-specific siRNA research and evolving KRAS-directed immunotherapies. We conclude by outlining the current KRAS clinical trial landscape and future areas of investigation. Full article

This study presents a systematic investigation of laser surface hardening of 9CrSi tool steel with the aim of establishing the relationships between processing parameters, microstructural evolution, and resulting mechanical and tribological properties under the applied laser conditions. The influence of laser power, modulation frequency, and scanning speed on the hardened layer depth, microstructure, and surface properties was analyzed. Laser treatment produced a martensitic surface layer with varying fractions of retained austenite, while the transition zone consisted of martensite, granular pearlite, and carbide particles. X-ray diffraction identified the presence of α′-Fe, γ-Fe, and Fe₃C phases, with peak broadening associated with increased lattice microstrain induced by rapid self-quenching. The surface microhardness increased from approximately 220 HV_0.1 in the untreated state to 950–1000 HV_0.1 after laser hardening, with hardened layer thicknesses ranging from about 500 to 750 µm depending on the processing regime. Instrumented indentation showed higher elastic modulus values for all hardened conditions. Tribological tests under dry sliding conditions revealed reduced coefficients of friction and more than an order-of-magnitude decrease in wear rate compared with untreated steel. The results provide a parameter–microstructure–performance map for laser-hardened 9CrSi steel, demonstrating how variations in laser processing conditions affect hardened layer characteristics and functional performance. Full article

How does zirconia processing affect the degree of tetragonal to monoclinic phase transformation (t ⟶ m) and the development and wettability of the surface? One hundred and twenty-four samples made of sintered zirconium were divided into four groups based on the following treatments: grinding, polishing, sandblasting with Al₂O₃, or sandblasting with SiC. After surface treatment, the samples were subjected to the following tests: X-ray diffraction, microscopic examination, surface roughness measurements, and surface wettability. The highest values are achieved after the grinding process (R_a = 0.63; R_z = 9.29; R_q = 1.28), and the lowest values are found after polishing (R_a = 0.11; R_z = 0.71; R_q = 0.36). All samples, apart from those sandblasted with Al₂O₃ (Θ = 121.59°), showed wettability with the polar liquid. The best wettability was noted for sandblasted SiC samples (Θ = 41.22°) and the lowest was noted for polished samples (Θ = 80.61°). All samples showed wettability with an apolar liquid (Θ < 90°). A significant transformation (t ⟶ m) was noted in all tested samples: about 14% for ground, 17% for polished, 13.8% for Al₂O₃ sandblasting, and 13.1% for SiC sandblasting samples. The type of processing method has a significant impact on the selected parameters of roughness, surface wettability, and phase transformations. Full article

Electrical curing is a viable alternative to traditional thermal curing for geopolymer materials due to its capability for rapid and internal geopolymerization. In this research, reinforced geopolymer-based composite beams were successfully fabricated at a macroscale using a binary system of fly ash (FA) and granulated blast furnace slag (GBFS). The mixture was activated with a solution of sodium silicate (Na₂SiO₃) and sodium hydroxide (NaOH) with a fixed molar ratio of 2:1 for both, and aggregate-to-binder and activator-to-binder (A/B) ratios of 2.5 and 0.7, respectively. To ensure electrical conductivity, individual fiber systems were employed, including carbon fiber (CF), steel fiber (SF), and waste wire erosion (WWE), each incorporated at a dosage of 0.5 vol.% of the total mix volume. In addition, carbon black (CB) was introduced as a conductive filler at a constant dosage of 2.0 vol.% of the binder content in selected specimens. Each beam specimen contained only one type of conductive reinforcement or filler. A total of twelve reinforced geopolymer-based composite beams with a 150 mm square section and a span of 1300 mm, with a clear span of 1200 mm, were successfully cast and reinforced based on reinforced concrete beam designs and standards, with a dominant goal of enhancing beam behavior under flexure. The beams were cured in ambient curing conditions, or using thermal curing at 80 °C for 24 h, and using electrical curing from the fresh states with a fixed voltage of 25 V. Notwithstanding a common beam size and reinforcement pattern, distinct curing methods significantly influenced beam structure properties. Peak loads were between 20.8 and 31.5 kN, initial stiffness between 1.75 and 6.09 kN/mm, and total energy absorption between 690 and 1550 kN/mm, with a post-peak energy component of between 0.12 and 0.55. Displacement-based ductility measures spanned from 3.2 to 8.1 units with a distinct improvement in electrical curing regimes, especially in the SF-reinforced specimens; this indicates that electrical curing in reinforced geopolymer composite materials works as a governing mechanism in performance rather than simply a method for enhancing the strength of materials. Full article

Background/Objectives: Cutaneous leishmaniasis (CL) remains a major neglected tropical disease, and current chemotherapeutic options are limited by toxicity and emerging resistance. Repurposing azole antifungals is a promising approach, as they target ergosterol biosynthesis, a pathway also essential in Leishmania spp. This study investigated the antileishmanial potential of econazole through in vitro and in vivo assays. Methods: Econazole activity was evaluated against Leishmania amazonensis promastigotes and intracellular amastigotes using MTT and luminescence-based methods. Cytotoxicity in NCTC cells was determined to calculate the selectivity index (SI). Drug interactions with miltefosine were assessed by fixed-ratio isobologram analysis. In vivo efficacy was examined in BALB/c mice infected with L. amazonensis and orally treated with econazole (2.5, 5, or 10 mg/kg/day) for 28 days. Lesion development and parasite burden were monitored. Molecular docking simulations were performed using SwissDock. Results: Econazole showed potent in vitro activity, with EC₅₀ values of 8.9 µM for promastigotes and 11 µM for intracellular amastigotes, and a CC₅₀ of 31 µM. Isobologram analysis revealed additive interactions with miltefosine (ΣFIC 0.5–1.2; mean 0.95). In vivo, econazole reduced lesion size and parasite load, achieving up to 75% reduction at 10 mg/kg/day. Docking results suggested that econazole may inhibit sterol biosynthesis, potentially through interaction with 14α-demethylase. Conclusions: These findings provide the first evidence of econazole activity against L. amazonensis in vitro and in vivo. Its exploratory efficacy and compatibility with miltefosine support further investigation of econazole as a repurposed candidate for CL, including optimization of dosing strategies and combination regimens. Full article

This study systematically examines the fluidity, setting time, mechanical properties, and microstructural evolution of metakaolin-based geopolymer grouting materials with a relatively high water-to-solid (W/S) ratio window. A four-factor, three-level orthogonal experimental design was employed to identify the dominant factors and main effect trends of W/S ratio, alkali dosage, water glass modulus (Ms, molar ratio of SiO₂ to Na₂O in alkali solution), and steel slag content on the material’s performance. The results indicated that the W/S ratio predominantly governed fluidity, while the alkali content was the primary controlling factor for setting time and early-age strength. An intermediate range of water glass modulus with a value of 1.6 provided balanced performance. The incorporation of steel slag with a range of 10–20% showed an age-dependent contribution: it not only tended to improve the rheology of the paste but also the later-age strength. XRD, FTIR, and SEM/EDS results suggested that the hardened binders were dominated by amorphous products, where alumimosilicate gel (N-A-S-H) and Ca-containing gel (C-S-H/C-A-S-H) may coexist depending on calcium availability and activator chemistry. The proposed parameter ranges are valid within the studied design space and provide guidance for the mix design of high-W/S geopolymer grout. Full article

This study examines the functional degradation of crystalline silicon photovoltaic cells after 17 years of field exposure in the Adrar Desert, Algeria. Harsh thermal, radiative, and mechanical conditions accelerate aging, affecting electrical performance and structural stability. Monocrystalline silicon cells were extracted and analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, electrical resistivity measurements, and vibrating sample magnetometry (VSM). SEM revealed microcracks, delamination, and corrosion products. EDS showed Ag, Si, O, and C signals, while Raman indicated silicon features and signatures consistent with encapsulant (EVA) degradation. The temperature-dependent resistivity displayed a dual behavior with a minimum near ~72 °C, above which resistivity increased, consistent with a transition in the dominant transport mechanisms. VSM measurements showed an overall diamagnetic response with a weak hysteresis loop suggestive of defect-related contributions. The observed aging is primarily associated with oxidation, metal migration, and encapsulant degradation. These findings motivate more robust materials and interfaces for desert climates, alongside improved thermal management and active monitoring. Full article

When grinding silicon carbide, surface and subsurface damage have a significant impact on the product’s surface quality. One method to control the crack dimensions is laser irradiation on the SiC surface. The effect of this method on the grinding process is analyzed in this study. A series of experiments was carried out based on an orthogonal experimental design, with systematic adjustments made to laser parameters, including pulse energy (current), laser spot spacing, scanning times, and grinding process parameters. During the experiments, the grinding force was monitored by a dynamometer, and the specific grinding energy was calculated accordingly. Pulsed engraving laser modification effectively reduced the hardness of the ceramic surface layer by about 20%. The median and radial crack sizes induced by the laser in the subsurface layer ranged from 20.4 μm to 54.3 μm. This effectively inhibited further propagation of median and radial cracks during the grinding processes. Simultaneously, the tangential grinding force F_t was reduced by 30%. These conclusions were obtained through corresponding experiments that link surface roughness to laser power and grinding parameters. Using laser-induced controllable crack characteristics in the grinding process allow damage from surface and subsurface grinding to be controlled in brittle materials. Full article

The microstructure and wear behaviors of Mg₂Si/Al composites with 0 wt.%, 5 wt.%, and 10 wt.% SiC particles were studied using XRD, OM observation, SEM observation, EDS analysis, an extraction experiment, a hardness test, and the dry sliding wear test. It is shown by the results that after the addition of 10 wt.% SiC particles, the population of primary Mg₂Si particles increased, while the mean size of these particles reduced from 40 ± 10 μm (in the SiC-free composite) to 25 ± 8 μm. Both the matrix and the eutectic structure were refined. The tetrakaidecahedral morphologies of Mg₂Si crystals were confirmed by the results of extraction tests. The wear test results with GCr15 steel as the friction pair show that the Mg₂Si/Al composite with 10 wt.% SiC particles displayed more favorable wear resistance than the specimens with 0 wt.% and 5 wt.% SiC particle additions under both constant load and constant sliding velocity conditions. Under applied loads of 10 N, 20 N, and 30 N at a fixed sliding speed of 300 r/min, the wear rate of the Mg₂Si-Al composites reinforced with 10 wt.% SiC particles was 36.01%, 48.29%, and 23.32% lower than that of the SiC-free composites, respectively. When the sliding speed was set to 300 r/min, 550 r/min, 750 r/min, and 1000 r/min under a constant applied load of 20 N, the wear rate of the 10 wt.% SiC-reinforced Mg₂Si-Al composites was reduced by 40.37%, 40.87%, 26.20%, and 25.78%, respectively, compared with the SiC-free counterparts. The wear failure mechanisms of (Mg₂Si + SiC_P)/Al composites were mainly adhesive wear and abrasive wear, but the proportion of oxidation wear increased after the addition of the SiC particles. Full article

The long-term inhalation of free silica dust causes silicosis—a prevalent occupational hazard—yet its systemic effect on male reproductive toxicity remains underexplored. Tetrandrine (Tet) is the only plant-derived anti-silicosis drug approved in China. This study investigates silica (SiO₂) -induced male reproductive damage and evaluates Tet’s protective effects. Sixty male C57BL/6 mice (6–8 weeks) were divided into control, SiO₂ exposure, and SiO₂ + Tet groups. SiO₂ was administered via intranasal infusion and Tet via gavage. Mice were sacrificed at day 7 (male reproductive injury model corresponding to the pulmonary inflammation stage) and day 42 (male reproductive injury model corresponding to the pulmonary fibrosis stage). Analyses included sperm morphology, testicular transcriptome sequencing, RT-qPCR, and immunofluorescence. At day 7, SiO₂ exposure upregulated testicular inflammatory markers, which were partially mitigated by Tet. At day 42, SiO₂ increased sperm deformity and testicular fibrosis markers (fibronectin and vimentin); Tet intervention reduced these abnormalities. Transcriptome analysis revealed distinct gene expression patterns at day 7 versus day 42, indicating time-dependent injury mechanisms. Tetrandrine alleviates silica-induced reproductive damage in male mice, suggesting potential therapeutic applications for occupational silica exposure and expanding the understanding of silica toxicity beyond the respiratory system. Full article

In this work, the characteristic temperatures (solidus and liquidus) of selected lead blast furnace slags were investigated using in situ high-temperature optical microscopy. The effects of the basicity of the slag (CaO/SiO₂), the Fe/SiO₂ ratio, and the Zn content were investigated. The deformation temperature associated with the rounding of the sample edges and the temperature at which 75% of the sample height decreases were experimentally considered as the solidus and liquidus temperatures, respectively. The pseudoternary phase diagrams CaO-SiO₂-Fe_0.63Zn_0.37O and FeO-Ca_0.54Si_0.46O_1.46-ZnO were calculated, along with the crystallization curves, using the thermodynamic software FactSage to estimate the characteristic temperatures and phase evolution during the cooling of the slag. The difference between the calculated and experimental solidus and liquidus temperatures was about 70 °C. The results of XRD, SEM, and DSC analysis at high temperatures showed that spinel (ZnFe₂O₄), melilite (Ca₂ZnSi₂O₇), and andradite (Ca₃Fe₂Si₃O₁₂) were the base crystals for all slag samples. The liquidus temperature increases with decreasing slag basicity (CaO/SiO₂), while the liquidus temperature increases with increasing Fe/SiO₂ ratio or Zn content. Full article

This work investigates the structural, acoustic, and thermo-oxidative degradation behavior of elastomeric composites made from neat EPDM and recycled devulcanized EPDM (EPDMd) blends, both with and without silica (SiO₂). SiO₂ plays a complex role in degradation, possibly acting as a catalyst and also affecting the properties of the materials. Samples were subjected to accelerated degradation at 80 °C for 30 days. The characterization included the mechanical, spectroscopical (FTIR-ATR), thermal (TGA), and morphological (SEM) studies of the samples. Given EPDM’s use in construction as a sound-absorber, its acoustic properties were also analyzed. The determination of the mechanical properties shows that the incorporation of SiO₂ improves the Young’s modulus (YM), maintains the tensile strength (TS) at similar values, and causes a decrease in elongation at break (EB). The content of EPDMd slightly decreases both the TS and the EB and increases the YM. The thermo-oxidative degradation of the studied composites does not affect the TS values, but it increases the YM for the samples with and without SiO₂ for EPDMd contents higher than 40 phr, and decreases the EB for samples with and without SiO₂ for all EPDMd contents. The FTIR-ATR, TGA, and SEM results show that the addition of SiO₂ catalyzes the thermo-oxidative degradation process, while the EPDMd inhibits structural degradation. Migration of the ZnSt₂ included in the formulations to the surface is common in these elastomers. In this case, EPDMd forms microaggregates, which retain the exudation of ZnSt₂ crystals, especially in the non-degraded samples. The degraded samples present irregular structures, with microcavities, cracks, and occlusions, which increase the acoustic absorption mainly at frequencies below 1500 Hz. Full article

In this study, a laboratory-scale slag–steel reaction experiment was conducted to systematically evaluate the influence of the initial MgO content (3–7 wt.%) in LF refining slag on the cleanliness of GCr15 bearing steel. The assessment was performed from multiple perspectives by comparing the total oxygen content (T[O]) in molten steel, the inclusion area fraction, and the inclusion number density after 30 min of slag–steel interaction. To further elucidate the thermodynamic driving forces and kinetic mechanisms governing inclusion capture by slag, a predictive slag adsorption model was developed using an in-house computational code coupled with FactSage 8.1. Under conditions of slag basicity R (CaO/SiO₂) ranging from 4.0 to 8.0, MgO content varying from 0 to 7 wt.%, and a constant Al₂O₃ content of 32 wt.%, the chemical driving force ΔC (the mass-fraction difference between slag components and inclusions), the slag viscosity η, and the combined parameter ΔC/η were calculated at 1600 °C for three representative inclusion types: Al₂O₃, MgO·Al₂O₃, and MgO. In addition, the model was employed to quantitatively characterize the adsorption capacity of slag toward Mg–Al binary inclusions under varying MgO levels. Both experimental observations and model calculations demonstrate that the slag–steel reaction markedly enhances inclusion removal, as evidenced by pronounced decreases in T[O], inclusion number density, and inclusion area fraction after reaction. With increasing MgO content in slag, T[O] and inclusion-related indices exhibit a consistent trend of first decreasing and then increasing, reaching minimum values at an MgO level of 5 wt.%. Further analysis reveals a positive correlation between the apparent inclusion-removal rate constant ko and ΔC/η corresponding to MgO·Al₂O₃ inclusions. Moreover, the slag’s adsorption capacity toward Mg–Al binary inclusions decreases overall as the MgO fraction in inclusions increases. Notably, when the MgO content in inclusions exceeds 29 wt.%, the adsorption capacity undergoes an abrupt drop, indicating a pronounced cliff-like attenuation behavior. Full article