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Bone homeostasis encompasses two interrelated aspects: bone remodeling and cartilage metabolism. Disruption of bone homeostasis can lead to the development of metabolic bone diseases such as osteoporosis and osteoarthritis. The maintenance of bone homeostasis is a complex process that does not solely rely on the functions of the bone tissue itself. In fact, bone tissue is not an isolated entity; it is closely connected to other tissues in the body via exosomes. Within this interconnectivity, exosomes derived from both bone and non-bone cells interfere with each other, forming a complex regulatory network. Therefore, with cell origin as the guiding principle, we have delineated the bone regulatory network of exosomes, elaborated on the specific roles and regulatory mechanisms of exosomes derived from common cell types (cells within the skeletal microenvironment, stem cells from extra-osseous tissues, vascular-derived cells, muscle-derived cells, and neurogenic cells) in bone formation, bone resorption, and cartilage metabolism. We have also discussed the challenges faced in the field of exosome research related to bone homeostasis, unveiled the critical role of exosomes in maintaining bone homeostasis, and proposed that exosomes could serve as highly valuable therapeutic targets for metabolic bone diseases. [ABSTRACT FROM AUTHOR]

The excessive accumulation of nitrogen pollutants (mainly nitrate, nitrite, ammonia nitrogen, hydrazine, and urea) in water bodies seriously disrupts the natural nitrogen cycle and poses a significant threat to human life and health. Electrolysis is considered a promising method to degrade these nitrogenous pollutants in sewage, with the advantages of high efficiency, wide generality, easy operability, retrievability, and environmental friendliness. For particular energy devices, including metal-nitrate batteries, direct fuel cells, and hybrid water electrolyzers, the realization of energy valorization from sewage purification processes (e.g., valuable chemical generation, electricity output, and hydrogen production) becomes feasible. Despite the progress in the research on pollutant electrodegradation, the development of electrocatalysts with high activity, stability, and selectivity for pollutant removal, coupled with corresponding energy devices, remains a challenge. This review comprehensively provides advanced insights into the electrodegradation processes of nitrogenous pollutants and relevant energy valorization strategies, focusing on the reaction mechanisms, activity descriptors, electrocatalyst design, and actuated electrodes and operation parameters of tailored energy conversion devices. A feasibility analysis of electrodegradation on real wastewater samples from the perspective of pollutant concentration, pollutant accumulation, and electrolyte effects is provided. Challenges and prospects for the future development of electrodegradation systems are also discussed in detail to bridge the gap between experimental trials and commercial applications. [ABSTRACT FROM AUTHOR]

In contrast to the thermodynamically unfavorable anodic oxygen evolution reaction, the electrocatalytic urea oxidation reaction (UOR) presents a more favorable thermodynamic potential. However, the practical application of UOR has been hindered by sluggish kinetics. In this study, hierarchical porous nanosheet arrays featuring abundant Ni‐WO3 heterointerfaces on nickel foam (Ni‐WO3/NF) is introduced as a monolith electrode, demonstrating exceptional activity and stability toward UOR. The Ni‐WO3/NF catalyst exhibits unprecedentedly rapid UOR kinetics (200 mA cm−2 at 1.384 V vs. RHE) and a high turnover frequency (0.456 s−1), surpassing most previously reported Ni‐based catalysts, with negligible activity decay observed during a durability test lasting 150 h. Ex situ X‐ray photoelectron spectroscopy and density functional theory calculations elucidate that the WO3 interface significantly modulates the local charge distribution of Ni species, facilitating the generation of Ni3+ with optimal affinity for interacting with urea molecules and CO2 intermediates at heterointerfaces during UOR. This mechanism accelerates the interfacial electrocatalytic kinetics. Additionally, in situ Fourier transform infrared spectroscopy provides deep insights into the substantial contribution of interfacial Ni‐WO3 sites to UOR electrocatalysis, unraveling the underlying molecular‐level mechanisms. Finally, the study explores the application of a direct urea fuel cell to inspire future practical implementations. [ABSTRACT FROM AUTHOR]

The utilization of hydrazine in aiding water electrolysis presents a promising avenue for achieving highly efficient hydrogen production through energy conversion. Herein, bifunctional electrocatalyst of urchin‐like iron, nickle‐codoped cobalt phosphide supported on Ni foam (FeNi‐CoP/NF) is reported. Benefitting from the combined electronic structure and lattice strain engineering by Fe and Ni‐ codoping, the hydrazine‐assisted seawater electrolysis assembled with FeNi‐CoP/NF as both electrodes can achieve an industrial‐level current density of 1.5 A cm−2 at a record‐setting voltage of 163 mV at 70 °C and sustain stable operation for hundreds of hours in seawater environment. The existence of a potential coincidence region lends credibility to the feasibility of implementing self‐activated hydrazine‐assisted seawater electrolysis. Based on theoretical calculations, the separate and synergistic effects of electronic structure and lattice strain engineering are investigated and an integrated illustration of these two strategies on enhancing hydrogen evolution and hydrazine oxidation activity is provided. Moreover, an innovative multi‐powered hydrogen generation system featuring a direct hydrazine fuel cell, rechargeable Zn‐hydrazine battery, and hydrazine‐assisted seawater electrolysis is proposed, underscoring the unique advantages of hydrazine oxidation reaction and its prospective contribution to electrochemical energy conversion technologies powered by sustainable sources. [ABSTRACT FROM AUTHOR]