Abstract Electrical resistivity has proven to be a sensitive nondestructive evaluation (NDE) parameter for capturing both structural and durability-related deterioration in reinforced concrete, including corrosion, cracking, and delamination. This study develops a unified resistivity-based monitoring framework that functions primarily as a diagnostic and interpretative tool, integrating experimental diagnostics, quantitative damage indices, and sustainability-oriented assessment for condition-based management of concrete infrastructure. A conceptual diagnostic curve is formulated to represent characteristic resistivity trends associated with healthy concrete; corrosion-affected zones; compressive, tensile, and flexural cracking; and subsurface delamination, enabling mechanism-specific interpretation of measured values. Two resistivity-derived damage indices (DI) are introduced to normalize deviations from healthy-state benchmarks for both conductivity-increasing (corrosion and cracking) and conductivity-reducing (delamination) deterioration modes, with threshold ranges proposed for healthy, moderately damaged, and critically damaged conditions. The framework is experimentally validated across multiple concrete grades and exposure scenarios, demonstrating that electrical resistivity reliably captures the evolution of internal damage and electrochemical activity relevant to service-life assessment. To place the proposed methodology within a broader sustainability context, a structured Sustainable Development Goals (SDG)-based evaluation framework is used, indicating strong qualitative alignment with resilient infrastructure development, sustainable urban systems, and resource-efficient construction practices under SDG 9, SDG 11, and SDG 12. The proposed framework provides a practical, data-driven basis for early-stage damage diagnosis and informed maintenance decision-making, supporting sustainable life-cycle management of reinforced concrete structures.
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 degrees C). The liquid rapidly reached terminal rotation, attaining angular velocities up to similar to 13 rad s-1 within 1 s. For a liquid volume of 10 mL at 360 degrees C, the vane achieves an angular velocity of approximately 12 rad s-1, with a maximum extracted torque at zero angular speed of approximately 800 mu N m. 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 11 rad s-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.
