Search Results (310)

We propose an interactive approach to teaching Coulomb’s law and electrostatics in general, rooted in two complementary pedagogical methodologies: hyper-constructivism (H-C) and neo-realism. Unlike standard constructivism, our hyper-constructivist approach treats students’ prior ideas—even if incomplete or inconsistent—as essential “submerged logs” that teachers may use to guide students across the cognitive lake, toward the correct understanding. We implement a triadic model of cognitive didactics, balancing amusement (the ludic “hook”), formal teaching, and deepening scientific inquiry. Here, we present a hyper-constructivist path on electrostatics—Coulomb’s and Gauss’s laws. Through a sequential path of experiments involving plastic rods, “trained” aluminum cans, Volta’s electrophorus, and “Christmas” ornaments, we demonstrate how students can spontaneously formulate problems and bridge the gap between intuitive observations and complex effects of electrical polarization, going beyond the scholastic Coulomb’s law, via numerical modeling. The proposed interactive approach is rooted in phenomena-based learning and leverages discrepant events—surprising physical phenomena that challenge prior intuitions—as “ludic hooks” to trigger spontaneous inquiry and conceptual reconstruction. The main goal of our strategies is to trigger and develop young students’ interest in physics, which in many European countries is low. This method not only facilitates the acquisition of physical laws but also fosters “intellectual inquisitiveness” and social competencies, proving that well-rooted knowledge emerges from a synthesis of tangible experience and advanced scientific modeling. Our contribution constitutes a complex pedagogical proposal, iteratively developed and implemented in diverse didactical environments over several years. This paper presents a pedagogical proposal developed and refined through more than twenty years of educational practice. For teachers interested in implementing hyper-constructivist instruction, we provide a detailed teaching pathway on electrostatics, with didactical explanations and pedagogical notes. Full article

A new finite element simulation methodology for analyzing the mechano-electrochemical effects of Al alloys with intermittent measurement and reconstructed boundary conditions is proposed. It enables the simulation of the coupled mechano-electrochemical effects within the entire elastoplastic range of Al alloys. The model’s accuracy was verified through measurements of galvanic current, coupled potential, and corrosion morphology. This study indicates that the non-uniform stress distribution on a metal surface results in inconsistent electrochemical properties, leading to the spontaneous formation of anodes and cathodes and facilitating galvanic corrosion. Regions with stress concentration act as anodes in the corrosion reaction, while other areas serve as cathodes. The electrolyte domain is approximately polarized to the same potential, but there are also minor differences between different regions. As the stress concentration gradually increases, the mixed potential decreases, leading to greater polarization and an accelerated corrosion reaction rate. The galvanic current and the coupled potential calculated by the model differ from the measured values by less than 15%. Moreover, the observed corrosion morphology is consistent with the calculated results, indicating that the model provides good predictions of coupled mechano-electrochemistry. Full article

The chiral quark soliton model (CQSM) is an effective quark model of baryons maximally taking account of the most important feature of low-energy QCD, i.e., the spontaneous chiral symmetry breaking of the QCD vacuum and the associated appearance of Nambu–Goldstone pions. It shares many common features with the famous Skyrme model in that the baryons are viewed as rotating hedgehog objects in both models. Despite many similarities, it turned out that the CQSM can give more realistic predictions on most baryon observables. Above all, a decisive advantage of the CQSM over the Skyrme-like models is that it can handle non-local quark–quark correlations in baryons, which is absolutely impossible within the framework of effective meson theories. This feature is decisively important for making theoretical predictions on the quark distribution functions inside the nucleon, which are defined as nucleon matrix elements of bilinear quark operators with light-cone separation. In the present paper, we try to elucidate why and how the CQSM can give successful predictions for a variety of types of nucleon quark distribution functions, especially for the flavor asymmetry of the unpolarized and longitudinally polarized sea-quark (anti-quark) distribution functions in the nucleon. Full article

To explore the strong coupling between surface phonon polaritons (SPhPs) and quantum dots in one-dimensional periodic microstructures for quantum information processing, we establish a comprehensive theoretical model for SPhPs at air–polar dielectric interfaces. By rigorously deriving the dispersion relations, we reveal the decisive role of scale effects on bandgap formation: continuous spectra without bandgaps emerge at the nanoscale ($d\sim 10$–100 nm), whereas periodic modulation induces significant Bloch mode folding and tunable bandgaps (0.5–5 $\mathsf{\mu }\mathrm{m}$ width) at the microscale ($d\sim 1$–10 $\mathsf{\mu }\mathrm{m}$). Based on Fourier bandwidth limitations, we determine optimal channel widths ($L_y\ge 10 \mathsf{\mu }\mathrm{m}$) for maintaining low-loss modes with energy deviations below 1%. Through electromagnetic field quantization, we obtain analytical expressions for SPhP mode amplitudes and quantum dot transition rates. Calculations demonstrate that in micrometer-scale CsI structures, spontaneous emission rates can be modulated significantly: suppressed to <0.1 times the free-space values within bandgaps (excited-state lifetimes extended to ∼10 ns) and enhanced 5–8 times at conduction band edges. Leveraging these characteristics, we propose a scheme for batch quantum state manipulation of ${10}^2$–${10}^3$ arrayed quantum dots via selective excitation of specific Bloch modes using controlled laser frequency and angle, enabling parallel single-qubit gates with theoretical fidelity > 99%. Compared with surface plasmon polariton schemes, our approach utilizes the low-loss infrared characteristics of SPhPs ($Q\sim 100$–1000, 1–2 orders higher) to reduce decoherence rates, offering a new pathway for room-temperature solid-state quantum computing and on-chip multi-node entanglement distribution. Full article

Maintaining an appropriate balance of macrophage subpopulations throughout the wound healing process, using a graphene monolayer as a substrate, may represent a promising therapeutic strategy. In this study, the effect of a graphene monolayer on the polarization of RAW 264.7 macrophages was investigated using flow cytometry, fluorescence microscopy, and ELISA. Analysis of surface M1 (MHC II, CD80, CD86) and M2 (CD163, CD200R, CD206) markers demonstrated generally higher expression of M1 markers in M1-polarized groups (control, CM1; and graphene monolayer, GM1) compared to M2-polarized groups (CM2 and GM2), likely as a result of LPS and IFN-γ stimulation. Culturing macrophages on a graphene monolayer as a substrate for LPS- and IFN-γ-stimulated cells was associated with a trend toward reduced expression of all analyzed M1-associated markers compared with the control M1 group; however, this effect did not reach statistical significance. TNF-α secretion was higher in GM1 compared to CM0, GM0, and CM2. In contrast, surface markers alone were less conclusive for identifying M2 polarization, whereas intracellular markers such as ARG1 provided a more robust indication of the M2 phenotype. ARG1 expression was significantly elevated in CM2 and GM2 groups, with GM2 showing a significant increase relative to the control groups (CM0, CM1) and GM0 and GM1. These findings further support ARG1 and NOS2 as reliable markers of M2 and M1 polarization, respectively. The graphene monolayer did not induce spontaneous macrophage polarization. Only under M1 (LPS and IFN-γ) and M2 (IL-4 and IL-13) stimulation did it show a consistent trend toward modest modulation of macrophage polarization, possibly creating conditions conducive to tissue healing. Full article

Understanding the intrinsic Li–H₂ interaction, decoupled from substrate effects, is essential to rationalize the performance of lithium-decorated hydrogen storage materials. To address the current lack of a clean theoretical baseline, we characterized the sequential H₂ adsorption on the gas-phase Li₆ superatomic cluster using high-level density functional theory (DFT), complemented by Energy Decomposition Analysis (EDA), QTAIM, and NICS(0) calculations. Li₆ acts as a structurally rigid platform (RMSD < 0.032 Å) where ligand-induced polarization progressively strengthens its σ-aromaticity (NICS(0) from −2.917 to −13.98 ppm) and increases the HOMO–LUMO gap up to 5.05 eV. EDA identifies the binding as field-activated physisorption, electrostatically dominated (65–67%) and mechanistically distinct from Kubas coordination, as confirmed by QTAIM closed-shell interaction parameters. Negative cooperativity governs an effective loading capacity of n = 2 molecules under cryogenic conditions (T_eq = 143.76 and 114.64 K), while an entropic bottleneck renders higher loading non-spontaneous at all temperatures. These results establish Li₆(H₂)_n as a foundational gas-phase reference, providing a systematic, contamination-free descriptor set for the intrinsic Li–H₂ interaction. This framework is essential for isolating the electronic role of the lithium superatom and unambiguously identifying substrate-induced modulations in supported hydrogen storage materials. Full article

This study investigates lignite, long-flame coal, coking coal, and anthracite to elucidate the rank-dependent evolution of coal macromolecular structure and pore systems. Elemental/proximate analyses, FTIR, XPS, ¹³C NMR, and low-temperature N₂ adsorption–desorption, combined with BET, BJH, and DFT models, were employed to quantify structural parameters, characterize pore-size distributions, and establish representative macromolecular models. The results show that coalification is accompanied by progressive aromatization and polycondensation. Low-rank coal contains abundant hydroxyl, carboxyl, and aliphatic side-chain structures, exhibiting low aromaticity and weak aromatic-ring condensation. With increasing rank, oxygen-containing groups and aliphatic chains are progressively removed, while aromatic carbon content and the bridgehead-to-peripheral carbon ratio increase markedly. High-rank coal is dominated by highly condensed aromatic lamellae, with lower molecular polarity and enhanced structural ordering and graphitization. Meanwhile, N and S occurrence modes evolve from edge-related reactive species to more stable heterocyclic configurations, reflected by increasing graphitic N and thiophenic S contents. Pore structures also change systematically: low-rank coal is characterized by open, multimodal mesopores; intermediate-rank coal shows compaction and mesopore collapse; and high-rank coal becomes micropore-dominated with a relatively closed network. The U-shaped variation in micropore and mesopore volumes with rank indicates coupled macromolecular polycondensation and pore reconstruction, providing a structural basis for spontaneous combustion propensity and coalbed methane occurrence. Full article

This work provides an integrated experimental and computational evaluation of the cationic surfactant Quaternium-22 (Q-22) as a potentially eco-compatible corrosion inhibitor for carbon steel (CS) in 1 M hydrochloric acid. Gravimetric analysis and electrochemical techniques, including electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), were employed over a temperature range of 20–50 °C. Q-22 exhibited mixed-type inhibition behavior, with efficiency rising to 97% at an optimal concentration of 277 μmol L⁻¹. Performance was concentration-dependent but diminished with increasing temperature, indicating partial inhibitor desorption at elevated temperatures. Thermodynamic evaluation confirmed a spontaneous adsorption process consistent with the Langmuir isotherm, involving a combined physisorption and chemisorption mechanism. Surface characterization via scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) measurement, and X-ray photoelectron spectroscopy (XPS) confirmed the formation of a coherent, hydrophobic inhibitor layer that substantially reduced surface roughness and corrosion damage. Theoretical investigations using density functional theory (DFT), natural bond orbital (NBO) analysis, and molecular dynamics (MD) simulations revealed strong adsorption energies and favorable electronic properties consistent with the inhibitor’s high experimental efficacy. Overall, the results demonstrate that Q-22 is a highly effective, eco-compatible corrosion inhibitor for CS in acidic environments, operating through a stable adsorptive film-forming mechanism. Full article

Magnetic fields, either imposed externally or produced spontaneously, are often present in laser-driven high-energy-density systems. In addition to changing plasma conditions, magnetic fields also directly modify laser–plasma interactions (LPI) by changing the participating waves and their nonlinear interactions. In this paper, we use two-dimensional particle-in-cell (PIC) simulations to investigate how magnetic fields directly affect crossbeam energy transfer (CBET) from a pump to a seed laser beam when the transfer is mediated by the ion-acoustic wave (IAW) quasimode. Our simulations are performed in the parameter space where CBET is the dominant process and in a linear regime, where pump depletion, distribution function evolution, and secondary instabilities are insignificant. We use a Fourier filter to separate out the seed signal and project the seed fields onto two electromagnetic eigenmodes, which become nondegenerate in magnetized plasmas. By comparing the seed energy before CBET occurs and after CBET reaches quasi-steady state, we extract the CBET energy gains for both eigenmodes in lasers that are initially linearly polarized. Our simulations reveal that, starting from a few MG fields, the two eigenmodes have different gains, and magnetization alters the dependence of the gains on laser detuning. The overall gain decreases with magnetization when the laser polarizations are initially parallel, while a nonzero gain becomes allowed when the laser polarizations are initially orthogonal. These findings qualitatively agree with theoretical expectations. Full article

Two-dimensional magnetic materials with weak spin-orbit coupling would endow them with great potential for applications in low-power spintronic logic devices. In this work, the stability and magnetism of nonmetal (N, O, F, P) doped 1T-ZrS₂ monolayers is systematically studied by using first principles calculations based on density functional theory. Pristine ZrS₂ monolayer is a nonmagnetic semiconductor with an indirect band gap of 1.15 eV. Among the configurations of nonmetal-atom adsorption, substitutional doping, and vacancy defects, fluorine adsorption on the ZrS₂ monolayer is regarded as an optimal doping strategy. At the concentration of 11.11% in F-adsorbed ZrS₂, the spontaneous magnetization of F-adsorbed ZrS₂ monolayer occurs at the ground state with the stable magnetic states; the magnetic moments are about 0.674 μ_B, which mainly originates from the hybridization between the p-orbitals of S atoms and F atoms (0.315 μ_B) and d-orbitals of Zr atoms (0.323 μ_B). Moreover, the F-adsorbed ZrS₂ monolayer under 0–4% strain delivers consistently low spin polarization energy with stable p-d hybridization, offering their promising potential for their practical applications in low-power spintronic devices. Full article

Background/Objectives: Cysteine cathepsins and their endogenous inhibitors have been shown to possess context-dependent functions in cancer progression, including the regulation of tumor metabolic pathways. Stefin B and cystatin C, intracellular and extracellular protease inhibitors, respectively, can modulate tumor biology through protease-dependent and protease-independent mechanisms. This study investigated their combined functions and potential roles as tumor promoters in breast cancer in a spontaneous breast cancer mouse model (PyMT mice). Methods: We generated PyMT transgenic mice lacking both stefin B and cystatin C (double-knockout, DKO) and compared their tumor growth kinetics, proliferation, apoptosis, and metastatic burden with those of wild-type control mice. Immunohistochemistry was performed to characterize tumor macrophage infiltration and polarization. Results: DKO mice demonstrated delayed tumor onset, significantly slower tumor growth, reduced proliferation, increased apoptosis, and fewer lung metastases compared to wild-type controls. Immunohistochemistry revealed enhanced macrophage infiltration of the tumors, accompanied by a pronounced shift toward antitumorigenic M1 (CD86⁺) polarization, while M2 (CD206⁺) populations remained unchanged, indicating an immunological reprogramming of the tumor microenvironment toward a pro-inflammatory, tumor-suppressive state. Conclusions: Our results demonstrated a potential function of stefin B and cystatin C as tumor promoters in breast cancer through complementary mechanisms. Simultaneous depletion of both inhibitors revealed synergistic effects and remodeled the immune microenvironment to favor tumor suppression. These results suggest previously unknown roles for stefin B and cystatin C in tumor development and progression, which encourage further investigation of the cancer metabolic mechanisms underlying tumor behavior and their dynamic interplay with the microenvironment. Full article

Pancreatic cancer is characterized by an immunosuppressive tumor environment in which macrophages are recruited and reprogrammed to support tumor growth. Studying macrophage migration and polarization is crucial for understanding disease progression and identifying therapeutic targets. However, existing in vitro methods such as the transwell assay provide limited spatial resolution and do not allow visualization of cell movement or morphological changes. Here, we established and evaluated the Chamber Gap Assay, a modified two-compartment culture system that enables direct, time-resolved observation and quantification of macrophage migration toward pancreatic cancer cells as well as phenotypic alterations. Using murine and human macrophage–cancer cell models, we compared the performance of the Chamber Gap Assay with the transwell assay. We found that macrophage monocultures displayed substantial spontaneous migration in the transwell system, while cancer cells induced only modest additional macrophage recruitment. In contrast, the Chamber Gap Assay demonstrated clear and highly significant directional macrophage movement toward cancer cells, with distinct migration patterns and improved sensitivity for detecting group differences. The method also enabled visualization of cancer cell movement within the same system. Furthermore, CGA offers observations of morphological changes in immune cells under the influence of pancreatic cancer cells. Our findings indicate that the Chamber Gap Assay provides a robust and physiologically relevant method for studying tumor-induced immune cell recruitment and associated morphological changes. Full article

Bismuth layer-structured ferroelectrics (BLSFs) are core candidates for high-temperature piezoelectric applications owing to their excellent thermal stability and fatigue resistance, yet traditional Bi₄Ti₃O₁₂ (BiT)-based ceramics suffer from limited piezoelectric performance. To address this, MBi₄Ti₄O₁₅-Bi₄Ti₃O₁₂ (M=Ba, Sr, Ca) symbiotic structure bismuth-layered piezoelectric ceramics were fabricated via the conventional solid-state reaction method. Their crystal structure, microstructure, and electrical properties were systematically characterized using a X-ray diffractometer, scanning electron microscope, high-temperature dielectric spectrometer, and quasi-static d₃₃ meter to explore the effects of different A-site divalent elements. Results show that all samples form a pure-phase symbiotic structure with the P2₁am space group, without secondary phases. The lattice constant decreases with increasing A-site ionic radius, while symbiosis-induced lattice mismatch and long-range disorder refine grains, reduce aspect ratio, lower conductivity, enhance spontaneous polarization, and improve piezoelectric properties. The ceramics exhibit d₃₃ of 10 to 15 pC/N and T_C of 502 to 685 °C, with SrBi₄Ti₄O₁₅-Bi₄Ti₃O₁₂ showing optimal comprehensive performance (d₃₃ ≈ 15 pC/N, T_C = 593 °C, tanδ = 0.6% at 1 kHz/475–575 °C, and a low AC conductivity of 5.3 × 10⁻⁵~4.8 × 10⁻⁴ S/m). This study improves bismuth-layered ceramics’ performance via A-site regulation and symbiotic structure design, offering theoretical and technical support for high-performance lead-free high-temperature piezoelectric ceramics. Full article

Two structurally tunable (propyl-3-ol)triphenyltin(IV) (Ph₃SnL₁) and (butyl-4-ol)triphenyltin(IV) (Ph₃SnL₂) compounds were investigated at the human serum transferrin (Tf) molecular interface to resolve how ligand architecture and protein metallation modulate organotin(IV) biocompound stability and lobe-selective binding. Steady-state fluorescence spectroscopy revealed efficient quenching of native Tf emission (λ_ex = 280 nm, 296–310 K, pH 7.4) without significant spectral displacement, indicating the predominant formation of non-fluorescent ground-state complexes. Calculated bimolecular quenching constants (K_q ~10¹² M⁻¹ s⁻¹) exceeded the diffusion-controlled aqueous limit, ruling out a collisional dynamic quenching mechanism and confirming static complexation as the principal origin of fluorescence suppression. Double-log binding analysis revealed moderate affinity (K_a ~10²–10³ M⁻¹) and an approximately single dominant binding event per protein (n ≈ 0.65–0.90). Temperature-dependent van’t Hoff evaluation yielded positive ΔH° and ΔS° values, supporting a spontaneous, entropy-favored association process largely governed by hydrophobic and dispersion-type contributions, consistent with lipophilic organotin(IV) scaffold accommodation. Iron (Fe³⁺) loading of Tf markedly enhanced ligand engagement, especially for Ph₃SnL₁, evidencing that metallation-induced lobe closure reshapes pocket accessibility and local polarity relevant for organotin(IV) binding presentation rather than simply strengthening empirical docking scores. Molecular docking localized the most stable Ph₃SnL₂ poses in the sterically confined, rigid C-lobe, while Ph₃SnL₁ preferentially penetrated the more adaptive N-lobe. ONIOM QM/MM refinement of docking poses confirmed strong interfacial stabilization (ΔE_int ≈ –38 to –62 kcal mol⁻¹) and clarified charge–packing interplay without invoking frontier orbital analysis. The results map multiscale structure–interaction relationships defining lobe preference and complex stability at the transferrin interface. Full article

Background/Objectives: MHY498, a tyrosinase inhibitor, exhibits poor water solubility, which limits its topical delivery. Despite the importance of solubility data in rational formulation design, comprehensive information on its solubility behavior in various solvents and across a range of temperatures remains limited. Thus, this study aimed to systematically evaluate the solubility characteristics of MHY498 and to develop a nanosuspension formulation using an antisolvent precipitation approach to facilitate the development of an optimized topical formulation. Methods: In this study, we measured the solubility of MHY498 in various monosolvents and diethylene glycol monoethyl ether (DEGME) + water solvent mixtures at 293.15–313.15 K using a solid–liquid equilibrium technique. Based on these solubility data, MHY498 nanosuspensions were prepared via antisolvent precipitation guided by a Box–Behnken design matrix. In vitro skin permeability was also assessed using a Franz diffusion cell system to assess the topical delivery potential of the MHY498 nanosuspensions. Results: Among the investigated monosolvents, MHY498 exhibited the highest solubility in dimethylformamide, dimethylacetamide, DEGME, while the lowest solubility was observed in water. The solubility increased with temperature and DEGME content in solvent mixtures, and the experimental data were well described by thermodynamic and semi-empirical models, indicating an endothermic and spontaneous dissolution process. Solvent–solute interaction analysis revealed that hydrogen-bonding and nonspecific polarity interactions played key roles in enhancing MHY498 solubility. All nanosuspensions prepared within the design space exhibited particle sizes below 150 nm, and the optimized formulation achieved an average particle size of 28.1 nm. The optimized nanosuspension demonstrated a 3.3-fold increase in the cumulative permeated amounts compared with the conventional microsuspension. Conclusions: These findings demonstrate that a rational solvent selection strategy based on thermodynamic solubility analysis and antisolvent precipitation enables effective nanosuspension formulation of MHY498. The DEGME–water system was identified as a formulation-relevant solvent environment that supports both adequate drug solubilization and reproducible formation of nanosized particles. The resulting nanosuspension exhibited favorable particle size characteristics and enhanced formulation feasibility for topical applications. Therefore, it was shown that the developed nanosuspension system, established through a solubility-driven systematic approach, represents a promising strategy for improving topical delivery of MHY498. Full article