We establish a new weighted regularity criterion for weak solutions of the 3D Magnetohydrodynamic (MHD) equations, involving only the gradient of the velocity field. It is proved that a weak solution (u,b) is smooth on R3×(0,T) provided supx0∈R3‖|x−x0|β∇u‖Lα(0,T;Lγ(R3))<+∞with 2α+3γ=2−β, 32−β<γ≤94−3β, 3≤α<∞ and −23≤β≤13. Our result improves and extends some known scaling-invariant regularity criteria for the 3D MHD equations, albeit under stronger restrictions on the admissible ranges of α and γ.
The alkali and alkaline earth metals (AAEMs) in biomass ash significantly influence the yield and compositional distribution of bio-oil derived from fast pyrolysis. This study employed corn stover to systematically investigate the selective removal of AAEMs through stepwise demineralization pretreatment (SDP, distilled water, ammonium acetate, and hydrochloric acid) and their impacts on bio-oil composition. Furthermore, the effects of AAEMs-impregnated salts types (K, Ca, Na, Mg), salt concentrations (0.5%, 2.5%, 5%), and different potassium salt anions (Cl-, SO42-, NO3-, CO32-, HCO3-, AC(-) and PO43-) on bio-oil components were comprehensively examined. Results showed that the removal efficiency of AAEMs was enhanced with increasing acidity of demineralizing solutions, and AAEMs in biomass were categorized into three occurrence states: water-soluble metal (K), ion-exchangeable metals (Ca and Mg), and acid-insoluble metal (Na) according to SDP. During subsequent fast pyrolysis, AAEM-impregnated salts acted as catalysts promoting secondary degradation of pyrolytic intermediates (e.g., levoglucosan), leading to the concurrent formation of light oxygenated compounds and hydrocarbons (e.g., furans, ketones, and long-chain alkane). Different potassium salt anions substantially influenced the secondary cracking of anhydrosugars and the cleavage of aryl-ether bonds/phenolic hydroxyl groups in lignin. The proton affinity of anion governed the degradation sequence for anhydrosugars: HCO3- > CO32- > AC(-) > PO43- > Cl- > NO3- > SO42-, while the cleavage efficiency of lignin linkages followed CO32- > Cl- > HCO3- > PO43- approximate to AC(-) > SO42- approximate to NO3-. This work provides fundamental insights for targeted regulation of bio-oil composition through AAEMs management.
Bacterial infections and rapid degradation remain significant challenges for biodegradable magnesium (Mg) alloy implants. While conventional photothermal antibacterial coatings often rely on exogenous agents, the intrinsic photothermal potential of phosphate materials warrants greater exploration. In this study, amorphous calcium phosphate (CaP), zinc phosphate (ZnP), and magnesium phosphate (MgP) coatings were fabricated on WE43 Mg alloys via a facile chemical deposition method utilizing ultra-low pH solutions. Characterization revealed that these amorphous coatings exhibited exceptional photothermal performance. Upon near-infrared (NIR) irradiation (808 nm) for 240 s, the maximum surface temperature of these amorphous phosphates reached 240.5 °C. The coatings maintained robust photothermal responses in PBS and ex vivo tissue models. Mechanistically, unlike well-crystallized counterparts, the amorphous phosphates possess abundant lattice defects, creating numerous defect energy levels within their bandgaps that facilitate localized photon absorption and phonon-mediated heat generation. Furthermore, the coatings provided substantial corrosion protection for the Mg substrate. This bandgap engineering strategy via structural disorder offers a shift for designing antibiotic-free, smart antibacterial biomaterials with excellent stability and biocompatibility.
Gamification of learning has been regarded as an important pedagogy to promote students’ learning outcomes, and attempts have been made to integrate it into STEM education. However, the influence of gamification of learning on K-12 students’ STEM educational outcomes, such as domain knowledge, higher-order thinking, and affective outcomes, remains under-researched. This study aims to investigate strategies for integrating gamified learning in STEM education, examine its effects on domain knowledge, higher-order thinking, and affective outcomes, and explore K-12 students’ perceived benefits and challenges of implementing gamified learning in STEM education. We systematically reviewed 86 empirical studies involving 7,128 participants from leading bibliographic databases, examined the effects of gamified learning in STEM using a meta-analysis, and investigated the benefits and challenges of implementing gamified learning in STEM education using a qualitative synthesis. Our findings revealed medium to large effect sizes in favour of gamified learning on domain knowledge (Hedges’ g = .823; p < .001), higher-order thinking (Hedges’ g = .880; p < .001), and affective outcomes (Hedges’ g = .577; p < .001) using a random-effects model. The thematic analysis of interview data from 26 articles identified three themes with 15 sub-themes of benefits and three themes with six sub-themes of challenges of implementing gamified learning in STEM education. This review synthesized findings on the impact of gamified learning across STEM learning outcomes and various moderating factors, while also providing rich insights into authentic participant perceptions of its application in STEM education. This study yielded pedagogical and theoretical insights to effectively implement gamified learning in STEM education.
Phosphorus (P) is an essential macronutrient for plant growth and development, yet its limited availability in soil severely constrains crop productivity. To cope with phosphate (Pi) deficiency, plants have evolved a sophisticated signaling network centered on SPX domain proteins, which serve as central regulators of Pi homeostasis. Recent breakthrough structural studies have revolutionized our understanding of these proteins, revealing their function as cellular Pi sensors through binding of the inositol pyrophosphate InsP8. This review synthesizes current knowledge of SPX protein molecular structures, evolution, and functions within the Pi signaling network. We detail their sensing mechanism, focusing on inositol pyrophosphate binding and the subsequent control of PHR activity and phosphate starvation response (PSR) gene expression. Recent cryo-electron microscopy structures of rice SPX1-PHR2, Arabidopsis PHO1;H1, and human XPR1 have provided unprecedented insights into phosphate transport mechanisms and SPX domain regulation. We also discuss emerging functions of SPX proteins in coordinating arbuscular mycorrhizal symbiosis, plant immunity, nitrogen-phosphorus balance, and cold stress responses, highlighting their broad significance in plant biology. Finally, we discuss key challenges and future research directions crucial for translating these mechanistic insights into innovative strategies to enhance phosphorus use efficiency (PUE) in crops, including structure-guided protein engineering approaches.
