Search Results (310)

Based on a thermodynamic approach, a unified formula was proposed to describe distinct Hall–Petch relationships (HPRs) of unalloyed nanostructured materials (u-NSs: Fe, Cu, Ni, Pd, and Mo) and alloyed ones with low- or high-melting temperature alloying metals (low-T_m or high-T_m a-NSs: Ni_xMo_1−x, Fe_xZr_1−x, Ni_xCu_1−x, and Fe_xCu_1−x). As the grain size decreases to several nanometers, the yield strength first increases and then decreases for u-NSs and low-T_m a-NSs, obeying the inverse HPR (IHPR), while it monotonically increases for high-T_m a-NSs. For the former, the decrease is induced by the reduction in activation energies of interface migration and dislocation gliding, along with the thermally driven decline, lattice expansion, and bond weakening of interface atoms. In the latter case, the monotonic increase or the elimination of IHPR is relevant to the negative interface energy induced by the segregation of alloying atoms at grain boundaries. Our predictions are validated by the available experimental results. Full article

Cancer is one of the leading causes of disease-related death worldwide, and targeting key regulatory genes to induce programmed cell death in tumor cells has emerged as a crucial therapeutic strategy, following surgery, radiotherapy, and chemotherapy. As a mitochondrial outer membrane protein, NIX/BNIP3L can both mediate apoptosis to inhibit tumor cell growth and promote tumor cell survival by clearing intracellular reactive oxygen species (ROS) through mitophagy. Therefore, we summarize a brief overview of the structure and function of NIX/BNIP3L, as well as the mechanisms of NIX/BNIP3L generation and degradation, the role of NIX/BNIP3L in mediating apoptosis and mitophagy and to advance the understanding of the roles of NIX/BNIP3L in glioblastoma, lung cancer, hepatocellular carcinoma, breast cancer, pancreatic cancer, colorectal cancer and hematologic neoplasms, aiming to enhance treatment precision and improve patient outcomes. Full article

The development of lithium-ion batteries necessitates cathode materials that possess excellent mechanical and thermal properties in addition to electrochemical performance. As a prominent functional ceramic, the properties of spinel LiMn₂O₄ are governed by its atomic-level structure. This study systematically investigates the impact of Ni doping concentration on the mechanical and thermal properties of spinel LiNi_xMn_2−xO₄ via first-principles calculations combined with the bond valence model. The results suggest that when x = 0.25, the LiNi_xMn_2−xO₄ shows excellent mechanical properties, including a high bulk modulus and hardness, due to the favorable ratio of bond valence to bonds length in octahedra. Furthermore, this optimized composition shows a lower thermal expansion coefficient. Additionally, Ni doping concentration has a very minimal influence on the maximum tolerable temperature of the cathode material during rapid heating. Therefore, from the perspective of mechanical and thermal properties, this composition could be beneficial for improving the cycling life of the battery, since comparatively inferior mechanical properties and a higher thermal expansion coefficient make it prone to microcrack formation during charge–discharge cycles. Full article

The exponential growth of lithium-ion batteries (LIBs) in electric vehicles and energy storage systems has amplified the urgent need for sustainable recycling strategies. Conventional pyrometallurgical and hydrometallurgical methods for LIB recycling are energy-intensive, chemically demanding, and fail to preserve the structural integrity of cath-ode materials. Closed-loop recycling, in contrast, enables the recovery of layered oxides with minimal processing steps, reducing environmental footprint and supporting a circular economy. This study provides a systematic comparison of two regeneration approaches—sol–gel synthesis and hydroxide co-precipitation—for closed-loop recycling of layered NCM (LiNi_xCo_yMn_zO₂) cathode materials recovered from spent LIBs. Spent cells were mechani-cally processed and leached using malic acid to recover Ni, Co, Mn, which were subsequently used to synthesize NCM622 cathode powders. The regenerated materials were characterized using SEM/EDX, XRD, and electrochemical testing in CR2032 coin cells. Both methods successfully produced phase-pure layered oxides with the R-3m structure, with distinct differences in structural ordering and electrochemical behavior. The sol–gel-derived NCM622 displayed higher crystallinity and reduced cation mixing, evidenced by an I(003)/I(104) ratio of 1.896 compared to 1.720 for the co-precipitated sample, and delivered a high initial discharge capacity of 170 mAh/g at 0.1 C. However, it exhibited significant capacity fade, retaining only 60 mAh/g after 40 cycles. In contrast, the co-precipitation route produced hierarchical porous spherical agglomerates that offered superior cycling stability, maintaining ~150 mAh/g after 40 cycles with lower polarization (ΔE_p = 0.16 V). Both materials demonstrated electrochemical performance comparable to commercial NCM. Overall, hydroxide co-precipitation emerged as the most industrially viable method due to scalable processing, compositional robustness, and improved long-term stability of regenerated cathodes. This work highlights the critical influence of synthesis route selection in LIB closed-loop recycling and provides a technological framework for industrial recovery of high-value NCM cathode materials. Full article

CoCrNi medium-entropy alloys (MEAs) have emerged as a promising class of structural materials due to their exceptional strength–ductility synergy. However, the lack of composition-dependent predictive models severely hinders rational alloy design, forcing reliance on costly trial-and-error experimentation. This study develops a comprehensive theoretical model to predict the yield strength of single-phase face-centered-cubic (FCC) Co_(1-x-y)Cr_yNi_x MEAs by quantitatively evaluating the contributions of grain boundary and solid solution strengthening. The model demonstrates that increasing Cr content significantly enhances grain boundary strengthening through elevated shear modulus and Peierls stress, whereas Ni has a minimal effect. Solid solution strengthening, determined by the minimum resistance among Co–Cr, Co–Ni, and Cr–Ni atomic pairs, peaks at 1726.21 MPa for the composition Co₁₇Cr₆₄Ni₁₉. For equiatomic CoCrNi, theoretical yield strengths range from 1287.8 to 1575.4 MPa across grain sizes of 0.5–50 µm, showing excellent agreement with experimental results. This work provides a reliable, composition-dependent predictive framework that surpasses traditional trial-and-error methods, enabling efficient design of high-strength MEAs through targeted control of lattice distortion and elemental interactions. Full article

Furfural (FAL), an important biomass-derived platform molecule, plays a vital role in bridging biorefineries and the production of high-value chemicals through its selective hydrogenation to furfuryl alcohol (FOL). In this work, a series of Cu-based bimetallic catalysts (Cu₅Ni_x/SiO₂) were prepared by a simple impregnation method and exhibited outstanding catalytic performance for the hydrogenation of furfural under the mild conditions. When the loading of Ni was 2 wt%, the optimal catalytic activity was obtained at 150 °C and 1 MPa H₂, achieving a furfural conversion of 97.3%. This catalyst also showed excellent stability, maintaining high activity and selectivity toward FOL after five consecutive reaction cycles. Structural characterizations using X-ray diffraction (XRD), Hydrogen temperature-programmed reduction (H₂-TPR), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) revealed strong electronic interactions between Cu and Ni species. The introduction of Ni promoted the reduction of Ni²⁺ and improved the dispersion of Cu, which in turn increased the number of accessible active sites and facilitated the hydrogenation process. This synergistic effect between Cu and Ni provides an efficient and low-cost strategy for the selective hydrogenation of biomass-derived furfural to high-valued chemicals. Full article

While antiretroviral therapy (ART) has significantly improved the morbidity of HIV infection, ART may contribute to the pathogenesis of HIV associated neurocognitive impairment (HIV-NCI) by interfering with autophagic processes in astrocytes. Autophagy and mitophagy remove unwanted/damaged material and mitochondria from the intracellular environment, respectively. Dysregulated autophagy in astrocytes, abundant CNS cells with crucial homeostatic functions, contributes to many neurodegenerative diseases. Few studies have examined effects of ART on autophagy in astrocytes. We treated primary human astrocytes with a common ART regimen and performed LC3B-II and p62 turnover assays. ART significantly inhibited both LC3B-II and p62 turnover. Since p62, one autophagy receptor that mediates mitophagy, autophagic clearance of mitochondria, turnover was inhibited, we also examined mitophagy. While ART decreased BNIP3L/Nix homodimers, there were no changes in PINK1, Parkin, Mt-CO2, mitochondrial mass, or mitochondria–lysosome colocalization, indicating that ART did not inhibit mitophagy. We show that antiretroviral drugs have distinct effects on autophagic processes in astrocytes, which represents an alteration in their homeostasis, a major function of autophagy. This likely contributes to HIV-NCI. Understanding these impacts is important for improving ART for PWH, who have, by necessity, ongoing ART exposure. It also facilitates development of therapies for HIV-NCI that may include modulation of autophagy. Full article

Understanding the relationship between state-of-charge (SOC) and anisotropic lithium diffusion is essential for improving the durability of Ni-rich layered oxide cathodes. However, quantitative insights into directional lithium diffusivity and its influence on mechanical degradation remain limited. In this study, molecular dynamics (MD) simulations were performed for LiNi_xMn_yCo_zO₂ (NMC) compositions with varying nickel content and SOC levels to reveal composition- and direction-dependent lithium transport behavior. The numerical indices in NMC compositions (e.g., NMC111, NMC532, NMC811) indicate the relative molar ratios of Ni, Mn, and Co, respectively, in LiNi_xMn_yCo_zO₂. The results show that lithium diffusion is enhanced at low SOC, owing to the abundance of vacant sites, while diffusion along the out-of-plane (c-axis) direction is strongly constrained, particularly in Ni-rich systems. To bridge the atomistic and continuum scales, the SOC-dependent anisotropic diffusivities obtained from MD simulations were incorporated into a chemo-mechanical finite-element model of an NMC811 particle. The coupled analysis demonstrates that anisotropic and SOC-dependent diffusion accelerates lithium depletion and stress localization, elucidating the origin of particle cracking in Ni-rich cathodes. This multiscale framework provides quantitative parameters and mechanistic understanding critical for designing durable next-generation lithium-ion batteries. Full article

Nano- and micro-indentation have become essential tools for quantifying the micromechanical behavior of rocks beyond traditional macroscopic tests. This review summarizes the historical evolution, experimental methodologies, and interpretation models (e.g., Oliver–Pharr, Doerner–Nix, energy-based methods, Hertz/ECM/Lawn), with a particular focus on rock-specific challenges such as heterogeneity, anisotropy, and surface roughness. A structured literature survey (1980–August 2025) covers representative studies on shale, limestone, marble, sandstone, claystone, and granite. The transition from classical hardness measurements to advanced instrumented indentation has enabled more reliable determination of localized properties, including hardness, elastic modulus, fracture toughness, and creep. Special attention is given to the applicability and limitations of different interpretation models when applied to heterogeneous and anisotropic rocks. Current challenges include high sensitivity to surface conditions and difficulties in capturing the full complexity of natural rock behavior. Looking forward, promising directions involve intelligent systems that integrate AI-driven data analytics, robotic automation, and multiscale modeling (from molecular dynamics to continuum FEM) to enable predictive material design. This review aims to provide geoscientists and engineers with a comprehensive foundation for the effective application and further development of indentation-based testing in rock mechanics and geotechnical engineering. Full article

The importance of purple corn (Zea mays L.) varieties has increased due to their high anthocyanin contents both in the kernels and the degrained cob. The aim of this work was to separate anthocyanins from degrained purple-corn cobs to assess their pigmentation potential in food matrices. Two populations of purple corn were used, namely, Negro de Ixtenco (NIX) and Negro de Ixtenco x Negro de Perú (PIX), collected in Juchitepec, Mexico. Flours of degrained cob were obtained with average moisture, crude protein, ash, lipid, crude fiber, and carbohydrate contents of 7.06, 3.70, 4.48, 0.76, 37.73, and 46.27%, respectively. Aqueous biphasic systems composed of a mixture of 7.88% trisodium citrate, 2.63% citric acid, and 50.88% ethanol were applied at an atmospheric pressure of 77,993.0 Pa and 25 °C, aided by ultrasound and orbital agitation. Extracts with anthocyanin concentrations of 33.01 and 39.55 mg per gram of degrained corn cob were obtained from NIX and PIX, respectively. Pigmentation kinetics were assessed in yogurt and corn dough, which had a logarithmic tendency towards hue angles of 2.25 and 333.05°, respectively. A 60% pigmentation relative to the limit was suggested, which required 0.45 and 11.65% of the extract in yogurt and corn dough, respectively. Pigmentation stability was verified in refrigerated yogurt and in cooked corn dough. Full article

The demand for high energy density in mobile devices (including vehicles and small ships) is increasing. Nickel–Manganese–Cobalt (NMC) ternary, as a battery cathode material, is increasingly being applied because of its higher energy density relative to LiFePO₄ or other traditional materials. But NMC also faces challenges, such as a high degeneration rate and heat generation. So these aspects of Ni content must be clarified. In the current study, two Ni-content battery cells were tested, and the results of other composition cathode cells from the literature were compared. And three typical Ni-content batteries were simulated for searching Ni effects on performance, capacity fade and heat generation. Some findings were achieved: (1) from 0.8 Ni content, it can be seen that the specific capacity growth rate (slope) was much greater than before; (2) cathode materials that have an odd number (that does not surpass 0.7) of Ni content showed a linear capacity degradation trend, but others did not; (3) the Li concentration within material particles did not correspond to absolute stress value but stress temporal gradient; and (4) during discharge, lower Ni content made the heat peak occur earlier but lowered the absolute value; the irreversible heat increased with Ni content non-linearly, so that the higher the Ni content went up, the higher the increase rate of the irreversible heat ratio. Thus, the results of this study can guide the design and application of high energy batteries for mobile devices. Full article

Ischemic stroke induces complex neuroinflammatory cascades, where microglial autophagy and mitophagy serve dual roles in both injury amplification and tissue repair. This scoping review synthesized current evidence on their regulatory mechanisms and therapeutic implications. Literature was identified via PubMed and Embase, yielding 79 records, from which 39 original research articles and 13 review papers were included after eligibility screening. Search terms included “microglia,” “autophagy,” and “ischemic stroke.” Protective autophagy was frequently associated with AMPK activation, mTOR inhibition, and mitophagy pathways such as PINK1/Parkin and BNIP3/NIX, facilitating mitochondrial clearance, M2 polarization, and anti-inflammatory signaling. Therapeutic agents such as rapamycin, Tat-Beclin 1, and Urolithin A consistently demonstrated neuroprotection in preclinical stroke models. In contrast, excessive or prolonged autophagic activation was linked to inflammasome amplification, oxidative stress, and phagoptosis. Limited human studies reported associations between elevated serum ATG5 levels or ATG7 polymorphisms and worse clinical outcomes, suggesting preliminary translational relevance. These findings support the potential of phase-specific modulation of microglial autophagy as a therapeutic avenue for stroke, although further validation in human models and development of autophagy biomarkers are needed for clinical application. Full article

Cobalt and Nickel (Co, Ni) co-doped magnesium oxide (MgO) nanoparticles (NPs) have been synthesized using the coprecipitation method. The structural, chemical, and optical properties of the as-synthesized NPs are systematically investigated using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and UV-visible spectroscopy. It is found that the optical bandgap of co-doped MgO NPs reduces from 2.30 to 1.98 eV (14%) with increasing Ni dopant concentrations up to 7%. The Co_0.05Ni_0.07Mg_0.88O NPs exhibit a high photocatalytic degradation efficiency of 93% for methylene blue dye (MB) under natural sunlight irradiation for 240 min. Our findings indicate that the Co_0.05Ni_xMg_0.95−xO NPs have strong potential for use as photocatalysts in industrial wastewater treatment. Full article

The half-Heusler (HH) compound NbCoSn, with 18 valence electrons, is a promising thermoelectric (TE) material due to its favourable electrical properties and excellent thermal and chemical stability. Enhancing its TE performance typically involves doping and microstructure engineering. In this study, Ni was introduced into NbCoSn to form NbCoNi_xSn (x = 0–1), and the effects of Ni content on the microstructure and TE properties were systematically investigated. At low doping levels (x ≤ 0.05), Ni occupies interstitial sites, forming NbCoNi_xSn solid solutions. At higher concentrations (x > 0.05), full-Heusler (FH) secondary phases emerge, resulting in HH–FH composites. The introduction of Co/Ni interstitials enhances TE performance by creating in-gap electronic states and increasing phonon scattering through point defects. A clear structural transition from HH to FH phases is observed with increasing Ni content. The highest figure of merit, ZT ≈ 0.52 at 975 K, was obtained for NbCoNi_0.05Sn, comparable to the best values reported for this system. Full article

Low-permittivity microwave dielectric ceramics are essential for high-frequency communication and radar systems, as they minimize signal delay and interference, thereby enabling compact and high-performance devices. In this study, LiAl_5−xNi_xO_8−0.5x (x = 0.1–0.5) ceramics were synthesized via a solid-state reaction method to investigate the effects of Ni²⁺ substitution on crystal structure, microstructure, and dielectric properties. X-ray diffraction and Rietveld refinement reveal a phase transition from the P4₃32 to the Fd$\stackrel{-}{3}$m spinel structure at x ≈ 0.3, accompanied by a systematic increase in the lattice parameter (7.909–7.975 Å), attributed to the larger ionic radius of Ni²⁺ compared to Al³⁺. SEM analysis confirms dense microstructures with relative densities exceeding 95% and grain size increases from less than 1 μm at x = 0.1 to approximately 2 μm at x = 0.5. Dielectric measurements show a decrease in permittivity (ε_r) from 8.24 to 7.77 and in quality factor (Q × f) from 34,605 GHz to 20,529 GHz with increasing Ni content, while the temperature coefficient of the resonant frequency (τ_f) shifts negatively from −44.8 to −69.1 ppm/°C. Impedance spectroscopy indicates increased conduction losses and reduced activation energy with higher Ni²⁺ concentrations. Full article