This study investigates a vane-driven Leidenfrost engine based on evaporation-induced self-propulsion of liquid volumes of deionized water on a radially ratcheted circular substrate. Asymmetric surface topography rectifies vapor flow beneath the levitated liquid, creating pressure gradients and viscous shear stresses that generate tangential motion, which is converted into rotation by a surrounding ratcheted wall. During its lifetime, the liquid shape progresses through ring, arc, and spherical regimes. External vanes coupled to the rotating liquid convert the self-propulsive torque of the liquid into a mechanical output. The rotational dynamics of the engine are examined using two-, four-, and eight-blade vane configurations across a range of liquid volumes (1 to 10 mL) and substrate temperatures (280 to 400 °C). The liquid rapidly reached terminal rotation, attaining angular velocities up to ∼13 rad s−1 within 1 s. For a liquid volume of 10mL at 360 °C, the vane achieves an angular velocity of approximately 12rads−1, with a maximum extracted torque at zero angular speed of approximately 800μNm. Higher liquid volumes produced greater torque as a larger fraction of the ratcheted surface interacted with the moving liquid arc. The Leidenfrost engine operated continuously for more than an hour under continuous liquid replenishment, maintaining an average angular velocity of 11rads−1. These results indicate that vane-driven Leidenfrost engines offer a promising strategy for continuous microscale power generation.
Hypoxia-inducible factor-1α (HIF-1α) is an oxygen-sensitive transcription factor with an inherently paradoxical biology: under mild-to-moderate hypoxic stress, it functions as a pro-survival regulator, yet under severe or prolonged hypoxia, the same signalling axis promotes apoptotic and autophagic cell death. This duality carries particular significance in neurons, where HIF-1α serves as a critical nexus among neuronal survival, metabolic adaptation, and mitochondrial integrity, and where the consequences of its dysregulation are most profound given their exceptional metabolic demands and limited regenerative capacity. This review examines the molecular determinants governing this protective-to-detrimental switch, integrating key interconnected dimensions: the context-dependent regulation of oxidative stress, the control of mitochondrial bioenergetics, dynamics, mitophagy, and axonal transport; the dual role of HIF-1α in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and cerebral ischemia; and the therapeutic implications of precision-targeted HIF-1α modulation. Across all these contexts, a consistent pattern emerges: early or acute HIF-1α activation is broadly neuroprotective, while chronic or severe hypoxic stress converts the same pathway into a driver of neurodegeneration. Understanding the determinants of this switch, including hypoxia duration, severity, and cell-type specificity, provides a framework for designing temporally precise therapeutic interventions for hypoxia-related neurological disorders.
Heterotrophic diazotrophic bacteria (HDB) are increasingly recognized as widespread and significant contributors to oceanic nitrogen fixation. Macroalgae are known to form stable associations with endophytic and epiphytic bacteria for their growth, development and defense. The red alga Kappaphycus alvarezii can grow under nutrient-limited conditions, suggesting that nutritionally beneficial microbial associations may help sustain its growth under these conditions. The present study investigated the presence of HDB associated with K. alvarezii by incubating surface sterilized thallus sections in nitrogen-limited media. The isolates were taxonomically identified using 16S rRNA gene analysis, and their diazotrophic potential was assessed by amplifying the nifH gene. Phylogenetic analysis revealed associations with diverse genera, including Yangia, Salipiger, Mangrovicoccus, Tritonibacter, Pseudooceanicola, Roseibium, Thalassospira, Oceanobacillus, Alteromonas, Marinobacter, Pseudomonas, Stutzerimonas and Tenacibaculum. Eleven percent of the isolates, including Salipiger sp., Yangia sp., Thalassospira sp. Mangrovicoccus ximenensis and Stutzerimonas stutzeri tested positive for the presence of nifH gene, indicating potential diazotrophic capability. Our findings indicate that K. alvarezii hosts a diverse assemblage of culturable bacteria with potential host-beneficial functions, highlighting the need for functional validation of their contributions to the nitrogen acquisition and fitness of K. alvarezii.
A novel binder-free SnO2/polyaniline (PANI) composite anode grown directly on carbon cloth (CC) is developed via a hydrothermal approach for high-performance Li-ion batteries. The integrated architecture eliminates inactive binders and current collector interfaces, enabling efficient electron transport and robust mechanical integrity. Compared with conventional SnO2 coated on a copper current collector and bare SnO2 grown on CC, the SnO2/PANI@CC electrode delivers markedly enhanced electrochemical performance, including higher discharge capacity, superior cycling stability, improved rate capability, and reduced cell resistance, as confirmed by comprehensive electrochemical analyses and post-cycling characterization. The electrode maintains a high reversible capacity of 1057 mAh g−1 after 100 cycles at a relatively high current density of 500 mA g−1 (0.5 C). Upon subsequently reducing the current density to 250 mA g−1, a capacity of 871 mAh g−1 is retained after 300 cycles, even in a Swagelok cell configuration. Notably, the improved capacity retention observed at higher current density is attributed to reduced lithiation-induced stress and mitigated volume expansion, resulting in lower structural degradation, a conclusion further supported by post-cycling analysis. The superior electrochemical behavior of the SnO2/PANI@CC electrode arises from the synergistic effects of the conductive PANI network and the direct growth on flexible carbon cloth, which together stabilize the electrode–electrolyte interface and effectively suppress mechanical failure during prolonged cycling. Overall, the binder-free SnO2/PANI@CC anode outperforms conventional graphite and many previously reported SnO2-based anodes, demonstrating strong potential for next-generation high energy Li-ion batteries.
Nickel-incorporated vanadium pentoxide (V2-2xNi3xO5-delta, 0.03 <= x <= 0.06) microparticles were synthesized and structurally characterized, revealing a biphasic composition dominated by orthorhombic V2O5 with Pmmn space group and a minor triclinic NiV2O6 phase with cap P 1 space group, as confirmed by Rietveld refinement. With increasing Ni content, the orthorhombic lattice parameters expanded due to ionic substitution. At the same time, the emergence of a distinct peak at 2 theta = 23.57 degrees indicated the onset of NiV2O6 phase formation, reaching 12.2 wt% at x = 0.05 and signifying a solubility-driven structural transition. X-ray photoelectron spectroscopy (XPS) revealed the presence of mixed oxidation states of Ni (Ni1+, Ni2+, Ni3+) and V (V4+, V5+), along with a chemically diverse oxygen environment comprising lattice oxygen, surface hydroxyls, and adsorbed oxygen species. The as-prepared compounds exhibited potent and broad-spectrum antimicrobial activity, demonstrating significant inhibition against the Gram-negative bacterium Pseudomonas aeruginosa and effective activity against the Gram-positive bacteria Staphylococcus aureus and Escherichia coli. The antimicrobial mechanism is attributed to a synergistic interplay of reactive oxygen species (ROS) generation, redox-mediated metal ion toxicity, and physical disruption of microbial membranes. Moreover, the increasing molar fraction of Ni enhanced antimicrobial efficacy, supporting a concentration-dependent increase in ROS production and microbial interaction.
