Search Results (4,807)

Background: Temozolomide (TMZ) resistance represents a major therapeutic challenge in glioblastoma treatment, where autophagy has emerged as a key adaptive survival mechanism. Although numerous studies have implicated autophagy in TMZ resistance, most have assessed this process at a single point, thereby overlooking its dynamic and time-dependent nature. Methods: In this study, we systematically investigated the temporal regulation of autophagy-related gene expression in two human glioblastoma cell lines with distinct MGMT methylation status and TMZ sensitivities (T98G and U87) following TMZ treatment. Cells were exposed to TMZ and harvested at defined time points (0 h, 6 h, 24 h, and 48 h). The expression levels of genes representing distinct stages of the autophagy pathway, including initiation, nucleation, elongation, selective autophagy, lysosomal function, and transcriptional regulation, were analyzed using RT-qPCR. Relative gene expression was calculated using the 2^−ΔΔCT method with GAPDH as the reference gene. Results: Our results reveal a time-dependent and phase-specific transcriptional reprogramming of the autophagy machinery in response to TMZ-induced stress. Early time points were characterized by modulation of autophagy initiation and nucleation genes, whereas intermediate and late phases showed prominent regulation of genes associated with autophagosome elongation, selective autophagy, autophagic flux, and transcriptional control. Conclusions: Collectively, these findings demonstrate that autophagy in TMZ-treated glioblastoma cells is not a static response but a dynamically regulated, multi-phase program. Specifically, in TMZ-resistant T98G cells, this process matures into a sustained adaptive program with robust late-phase lysosomal integration, while in TMZ-sensitive U87 cells, the early autophagic response is transient and fails to support long-term lysosomal coordination. This temporal perspective provides new insights into the role of autophagy in TMZ tolerance and underscores the importance of time-resolved analyses when targeting autophagy to overcome chemoresistance in glioblastoma. Full article

The increasing impact of climate change and resource scarcity demands energy-efficient and resource-conserving manufacturing strategies. Metal forming offers substantial potential for lightweight construction and material efficiency. Forming-induced ductile damage, particularly void nucleation and growth, is often neglected in component design. Industrial practice still relies mainly on macroscopic mechanical properties and safety factors, while microstructural damage evolution and its influence on fatigue performance are largely disregarded. This study investigates load-path-dependent fatigue behavior and damage mechanisms using axial and combined axial–torsional fatigue tests. Particular attention is given to the phase shift d between axial and torsional loading, which strongly affects fatigue life. The results indicate that axial loading dominates damage evolution, while load path interactions significantly change fatigue performance. A phase shift of d = 90° resulted in a significant increase in the number of cycles to failure, N_f, for different total strain amplitudes with the same rotational angle amplitude of θ = 10°. These findings highlight the importance of considering load-path-sensitive stress states in fatigue assessment of formed components. Fractographic analyses, AI-assisted 3D reconstruction, and confocal laser scanning microscopy support the experimental results. Full article

To study the influence of freckle defects on the hot deformation behavior and the inheritance of dynamic recrystallization (DRX) structure in GH4706 alloy, the microstructures of specimens with and without freckles and the evolution laws of hot-processing parameters were compared. Hot compression experiments were conducted on a thermal simulation testing machine at 950–1150 °C, strain rates of 0.001–1 s⁻¹, and 55% deformation. Freckle-containing specimens were tested under DRX critical conditions. The flow stresses of both specimens increase with strain rate or with decreasing temperature. The power dissipation coefficient (η) and instability value (ξ) follow complex laws. Electron back-scattering diffraction (EBSD) was used to analyze DRX microstructures and nucleation mechanisms. The DRX degree of freckle-containing specimens is lower, with a larger average grain size. The DRX mechanism initiates preferentially in freckle-containing specimens, and its volume fraction changes in a complex manner. Grain coarsening occurs in freckle-containing specimens at high temperatures and low strain rates. Freckle defects lead to significant differences in the DRX mechanism of GH4706 alloy. Freckle-containing specimens exhibit both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX), whereas freckle-free specimens primarily display DDRX and second-phase particle-stimulated nucleation (PSN). The presence of MC carbides and Laves phases within freckle defects provides nucleation sites, further supporting a typical second-phase particle-stimulated nucleation mechanism. Full article

Cold Heavy Oil Production with Sands (CHOPS) creates high-permeability wormhole networks that strongly influence post-CHOPS recovery performance. Although CSI is a promising post-CHOPS recovery method, the coupled effects of wormhole coverage and pressure depletion strategy on oil recovery remain insufficiently understood. In this study, microfluidic systems were employed to investigate the combined influence of wormhole length and pressure depletion strategy on CSI performance. Micromodels with varying wormhole lengths were used under different pressure-depletion strategies to examine oil production behavior over multiple CSI cycles. Macroscopic recovery trends were analyzed alongside microscopic observations of oil displacement, gas nucleation, and foamy oil development. The results show that increasing wormhole length enhances reservoir connectivity and solvent access, resulting in a 19% improvement in the total recovery factor by 19%. Lower depletion rates favor early cycles and capillary-driven recovery, whereas higher depletion rates become more effective in later cycles as gas expansion and foamy oil-assisted mechanisms intensify. An incremental pressure-depletion strategy that exploits this transition yielded the highest cumulative recovery rate at 46.3%. These findings show that wormholes amplify the impact of pressure depletion rate during CSI by enhancing reservoir connectivity and pressure communication, thereby increasing the effectiveness of adaptive depletion strategies in post-CHOPS reservoirs. Full article

Engineering carbon nanostructures directly on carbon fiber fabrics offers an effective route to constructing hierarchical multifunctional coating systems. In this study, methane-based chemical vapor deposition (CVD) was employed to investigate nanocarbon coating formation on woven carbon fabrics supported by electrodeposited Ni catalysts. Catalyst morphology was systematically engineered through surface pretreatment, electric-field configuration, and pulse electrodeposition. At 700 °C, methane activation was insufficient to sustain continuous nanocarbon growth, indicating a temperature-dependent activation threshold. Raising the growth temperature to 900 °C enabled sustained methane decomposition and produced dense nanocarbon coatings; hydrogen assistance suppressed amorphous deposition and promoted more ordered nanofilament features. Pulse electrodeposition refined Ni catalyst dispersion and nucleation density, improving coating uniformity compared with direct-current deposition. Structural ordering was further supported by Raman spectroscopy (D and G bands with an average ID/IG of 0.678 ± 0.068 for methane-grown samples versus 0.798 ± 0.011 for electrodeposition-only controls) and by HRTEM revealing multi-layer graphitic walls (~0.34 nm interlayer spacing). Together, the results support a methane-derived dissolution–diffusion–precipitation growth pathway governed by catalyst morphology, temperature, and gas composition. This controllable, textile-compatible catalyst engineering approach provides a scalable route to hierarchical graphitic coatings for carbon-fabric-based composites, electromagnetic interference shielding, and thermal management applications. Full article

Biocompatible nanocomposite hydrogels are emerging as versatile platforms in nanomedicine, particularly when natural proteins are used as both structural and chemical components. In this work, we report a green, simple, and rapid in situ synthesis of ultrasmall silver nanoparticles (uAgNPs) within a bovine serum albumin (BSA) hydrogel, in which albumin simultaneously acts as the reducing agent and three-dimensional scaffold. The confined reaction environment generated uniformly dispersed Ag nanostructures with diameters in the 4–40 nm range, as confirmed by DLS and TEM. High-resolution TEM revealed clear Face-Centered Cubic (FCC, 111) lattice fringes, demonstrating the crystalline nature of the embedded uAgNPs. Quantitative image analysis showed narrow size distributions and high circularities, consistent with cluster stabilization through protein–metal interactions. Rheological measurements further indicated that the incorporation of uAgNPs enhanced hydrogel stiffness and delayed yielding, reflecting a reinforcement effect mediated by the nanoparticles acting as additional cross-linking points. Moreover, when very small embedded uAgNPs are formed, the presence of emissive silver nanoclusters was found using fluorescence emission spectroscopy. Overall, our results show that BSA hydrogels provide an effective matrix for directing green uAgNP nucleation, ensuring high stability, controlled growth in less than 2 min, and improved mechanical properties. The resulting protein–nanoparticle composite constitutes a promising soft material for imaging, sensing, and other biomedical applications requiring stable, biocompatible nanoscale architectures. Full article

The solid-state transformation theory has been used to describe the formation of CuO nanowires during the oxidation of Cu metal in air. In order to fill the gaps of the nucleation mechanism of CuO nanowires, a quantitative model has been founded based on the classical nucleation theory, and the results show that the formation of the CuO nanowires is controlled by a solid solution precipitation process under steady-state heterogeneous nucleation circumstances, which will provide beneficial references for the analysis and preparation of metal oxide nanowires of other metal elements. Full article

Reliable detection of microplastics by surface-enhanced Raman scattering (SERS) is often hindered by poor particle–substrate contact and limited access to plasmonic hotspots on conventional planar substrates optimized for molecular adsorption. Here, we report a rapid microwave-assisted carbothermal shock strategy to fabricate silver nanoparticle-decorated electrospun carbon fibers (AgNPs@ECF) as a three-dimensional plasmonic platform tailored for solid microplastic sensing. Localized microwave-induced heating in a mixed ethanol–hexane system enables Ag nanoparticle nucleation and anchoring on conductive carbon fibers within 45 s, yielding a mechanically compliant, junction-rich architecture without chemical reductants or vacuum processing. The AgNPs@ECF composite was evaluated using morphologically weathered polystyrene (PS) and polyethylene terephthalate (PET) microplastics, along with size-controlled PS bead standards ranging from ~50 nm to 45 μm. Across these models, SERS response is governed primarily by particle–substrate contact geometry and near-field accessibility rather than polymer type. The strongest enhancement occurs in the sub-micrometer regime, where particles can engage multiple AgNP-decorated fiber junctions, while ultrasmall and large, smooth particles show reduced enhancement due to limited contact or rapid field decay. Spatially resolved Raman mapping and finite-difference time-domain simulations support a contact-dominated enhancement mechanism, revealing localized field confinement at particle–fiber interfaces. These results establish the design principles for three-dimensional SERS substrates targeting heterogeneous solid particulates, demonstrating that contact-accessible plasmonic architectures are critical for reliable microplastic detection under realistic solid-particle measurement conditions. Full article

Based on temperature–stress coupling simulation, a thermal source model for nanosecond pulsed hollow cathode electron beam surface modification is proposed. Dynamic thermal-stress changes from beam–surface interaction and their influence on micro–nano characteristics were systematically investigated. By analyzing maximum temperature/stress dynamics, cross-sectional remelted layer variations, and heating/cooling rates, the temperature and stress distribution in the micron-scale surface layer was comprehensively revealed, validating the model’s rationality. Combined with low, medium, and high pulse count experiments, the effects of thermal and stress factors on surface morphology and grain refinement were studied, elucidating underlying mechanisms through numerical correspondence. Results show irradiation effects confined to a 1.5–2 mm localized region, with extreme temperature changes (~10³ K) and stress variations (10³–10⁴ MPa) within tens of nanoseconds. Heating rates reached 10¹¹ K/s, cooling rates 10⁹–10¹⁰ K/s, exceeding microsecond pulsed beams by one to two orders. Simulated remelting zone diameter and thickness agreed well with experiments, confirming model validity. Grain refinement is primarily driven by rapid temperature distribution, generating instant solidification nucleation sites, with a secondary contribution from high-stress-induced plastic deformation forming sub-grains. Full article

Zinc-ion batteries have garnered significant research interest owing to their inherent safety, low cost, and environmental compatibility. Nevertheless, their widespread adoption is impeded by critical challenges including uncontrollable dendrite growth, parasitic side reactions stemming from active water molecules, and the corrosion of the zinc anode in conventional aqueous electrolytes. Herein, a hydrated deep eutectic solvent (HDES) electrolyte based on ZnSO₄, MnSO₄, and ethylene is proposed for high-performance zinc-ion batteries. This electrolyte demonstrates excellent stability and simultaneously enables the formation of a protective coating on the Zn anode surface. Spectroscopic analyses and theoretical simulations reveal that this electrolyte reconfigures the primary Zn²⁺ solvation shell by replacing water molecules with HDES components. This tailored solvation structure facilitates interfacial desolvation, elevates nucleation overpotential, and promotes uniform, dendrite-free zinc deposition. Simultaneously, a robust hydrogen bond network effectively sequesters free water, significantly suppressing the hydrogen evolution reaction and anode corrosion. Benefiting from these features, the HDES-based full cell delivers exceptional long-term stability, achieving over 2000 cycles at 3 mA cm⁻² with a capacity retention exceeding 95% and a Coulombic efficiency surpassing 85%. In sharp contrast, the traditional aqueous counterpart fails within only 200 cycles. This tenfold lifespan enhancement, coupled with cost-effectiveness and non-flammability, presents a promising strategy for advanced, grid-scale zinc-based energy storage. Full article

Neural interfaces created using thin-film fabrication rely primarily on conductive metal traces for electrical interconnects. Here, we explore the use of tantalum (Ta) metal interconnects as a replacement for noble-metal interconnects such as Au, Pt or Ir. Ta has been investigated previously for interconnect metallization in flexible silicon ribbon cables, but the structure and properties of tantalum for neural device metallization have not been extensively reported. In the present work, Ta metal was sputter-deposited onto amorphous silicon carbide (a-SiC), with and without a base titanium (Ti) adhesion layer, and investigated as interconnect metallization. In the absence of a Ti adhesion layer, resistivity measurements revealed a factor of six difference between Ta resistivity depending on the presence of the Ti base layer, with direct deposition on a-SiC nucleating high resistivity β-Ta (ρ = 197 ± 31 µΩ·cm, mean ± standard deviation) and Ta deposited on Ti nucleating low resistivity α-Ta (ρ = 35 ± 6 µΩ·cm). X-ray diffraction confirmed the existence of the two crystal structures. Ta feature sizes of 2 µm were created using photolithography and reactive ion etching (RIE). Finally, planar microelectrode array test structures using α-Ta and Au trace metallization with low-impedance ruthenium oxide (RuO_x) electrodes were fabricated and investigated by cyclic voltammetry (CV) and current pulsing in saline. These devices underwent 500 CV cycles between −0.6 and +0.6 V without evidence of degradation. In response to charge-balanced, biphasic current pulses at 4 nC/phase, a 21 mV increase in access voltage was observed with α-Ta metallization compared to Au. These results warrant further investigation of Ta as thin-film metallization interconnects for neural interface devices. Full article

Glycidyl azide polymer (GAP)-based polyurethane, a kind of energetic thermoplastic elastomer (ETPE), is a promising binder for advanced solid propellants, but its thermal decomposition involves overlapping competitive reactions that conventional single-step kinetic models cannot characterize accurately, limiting its engineering applications. To address this limitation, a constrained asymmetric Gaussian deconvolution strategy with fixed peak area ratios and shape constraints was developed in this work. This strategy was applied to resolve overlapping reaction rate curves converted from derivative thermogravimetric data of GAP-based ETPEs with 50 wt% GAP content at four heating rates of 5, 10, 15 and 20 K·min⁻¹. The complex decomposition process was successfully split into five stages, assigned to azide cleavage, polyether backbone scission, carbamate cleavage, hydrocarbon product degradation and residue decomposition, with a goodness of fit of R² > 0.998. Apparent activation energies of the five stages were determined through cross-validation by the Friedman and Flynn–Wall–Ozawa methods without prior assumption of reaction mechanisms, following the order of residue decomposition (181.4 ± 1.0 kJ·mol⁻¹) > hydrocarbon product degradation (159.9 ± 1.0 kJ·mol⁻¹) ≈ azide cleavage (156.5 ± 0.6 kJ·mol⁻¹) > backbone scission (135.1 ± 0.7 kJ·mol⁻¹) > carbamate cleavage (111.9 ± 1.1 kJ·mol⁻¹). Pre-exponential factors with lnA₀ values ranging from 22.2 to 34.0 were derived via the kinetic compensation effect. Finally, generalized master plots were employed to compare with classic solid-state reaction models for mechanistic insight, and the Šesták–Berggren model fit three major stages excellently (R² > 0.996) by accounting for synergistic nucleation-growth and phase boundary mechanisms, enabling high-precision kinetic equations. It should be noted that the constrained deconvolution method proposed in this work has general applicability for kinetic analysis of GAP-based ETPEs with different formulations and other complex energetic polymer systems, while the obtained kinetic parameters are composition-specific and only applicable to the corresponding ETPE formulation studied herein. Full article

The large-scale accumulation of titanium-extraction tailing slag (TS) poses environmental concerns, while its application is constrained by high impurity contents and low hydraulic reactivity, which is further exacerbated by the necessary dechlorination process. This study aims to evaluate the effectiveness of synthetic calcium silicate hydrate (C-S-H) nanocrystals in improving the performance of cement pastes incorporating deeply dechlorinated TS (DD-TS). To ensure uniform dispersion and activity, C-S-H seeds with varying crystallinities (55–94%) were prepared via a dynamic hydrothermal method (180 °C for 1–3 h) and incorporated into the composite binder in a wet-powder form at dosages of 0.5–2.0%. Results indicate that C-S-H-1, with the lowest crystallinity, offered the highest efficiency. At 1.5% dosage, the 1 d compressive strength increased by 64.6% to 18.6 MPa, while the initial setting time decreased by approximately 40%. Microstructural analyses reveal that poorly crystalline C-S-H provides abundant nucleation sites, accelerating early hydration and densifying the matrix to levels comparable to 7 d control pastes. These findings demonstrate the potential of C-S-H seeding for enhancing the utilization of DD-TS in cement-based materials. Full article

Background/Objectives: Stromal vascular fraction (SVF) from adipose tissue contains regenerative cell populations, including adipose-derived stem cells (ADSCs), and is increasingly used in clinical therapies. However, the effects of isolation technique and donor characteristics on SVF yield and viability remain unclear. This study aims to assess the impact of mechanical versus enzymatic isolation, as well as donor age and sex, on SVF total nucleated cell count (TNC) and viability. Methods: A retrospective analysis was conducted on 114 patients undergoing ADSC harvesting via a mini-liposuction. SVF was isolated using enzymatic digestion (n = 100) or mechanical digestion (n = 14). Percent viability and TNC were assessed using the Chemometec NC-200 NucleoCounter^®. The influence of isolation technique, donor age, and donor sex on SVF yield and viability was evaluated using Pearson’s correlation and independent t-tests. Results: Enzymatic digestion yielded significantly higher cell viability compared to mechanical isolation (p < 0.001), although no significant difference in TNC was observed between the two methods. Increasing donor age was modestly associated with reduced viability in enzymatically processed samples but not in mechanically processed samples. Donor age showed no significant association with TNC for either isolation method. Donor sex was not correlated with viability in either group; however, female donors exhibited significantly higher TNC following enzymatic digestion, a trend not observed with mechanical isolation. Conclusions: Enzymatic digestion preserves cell viability more effectively than mechanical methods, while donor age and sex have variable effects depending on the isolation protocol. These findings underscore the importance of considering both biological and methodological factors in SVF preparation for clinical use. Further studies with larger, balanced cohorts are needed to validate these results. Full article

Iron-based shape memory alloys (Fe-SMAs) are promising for structural retrofitting because of their low cost, corrosion resistance, and manufacturability. However, the effect of strain rate on the coupled thermo-microstructural evolution during cyclic training remains underexplored. In this study, samples underwent cyclic tensile training at quasi-static and impact strain rates. After each cycle, DSC was adopted to obtain transformation temperatures and enthalpies, and selected cycles were characterized by EBSD (KAM and IPF) to quantify phase fractions and variant statistics. Results show tensile loading shifts transformation temperatures, with the principal difference between regimes appearing in the evolution of martensite finish temperature. Under impact loading, the transformation enthalpy increases more rapidly (0.18 to 0.8 J/g in absolute value), and the driving force decreases more markedly by the fourth cycle (−0.0578 to −0.1117 J/g), indicating faster thermodynamic changes at high strain rates. Internal stress and dislocation storage accumulate faster under impact, lowering the effective stress (−17.01 MPa) for transformation and promoting martensite nucleation/growth. EBSD reveals increasing lattice distortion; in impact-trained samples, single-variant martensite and higher stored energy reduce interface resistance and enable elastic energy release, accelerating transformation and improving shape recovery. Full article