The increasing global demand for electricity has accelerated the integration of renewable energy sources, including solar photovoltaic (PV) systems, wind energy conversion systems (WECS), and battery energy storage systems (BESS), into modern power networks. Although these resources improve sustainability and reduce dependence on fossil fuels, their intermittent and variable nature introduces significant challenges related to system reliability, power quality, operational costs, and energy management, particularly in standalone and off-grid applications. This study presents a comprehensive review and analysis of both standalone and grid-connected renewable energy systems employed in distributed generation. Special emphasis is placed on evaluating the impact of renewable energy variability on system performance and reliability. Furthermore, the study investigates the role of green hydrogen technologies, including electrolyzes and fuel cells, as long-term energy storage solutions in hybrid renewable energy systems. The findings indicate that integrating green hydrogen with solar and wind resources can significantly enhance energy reliability, improve system flexibility, and ensure a continuous power supply in off-grid environments. The study highlights hybrid green hydrogen-based renewable energy systems as a promising pathway toward sustainable, reliable, and resilient future energy infrastructures.
Ventilatory pump failure is respiratory insufficiency caused by weakness of the inspiratory and expiratory muscles, leading to hypoventilation, hypercapnia, and ineffective cough rather than primary lung disease. This article analyzes five medicolegal cases in which conventional acute-care management of ventilatory pump failure resulted in death, anoxic injury, prolonged tracheostomy mechanical ventilation, or avoidable institutionalization. The cases were reviewed to identify recurrent clinical and legal failures, including removal of continuous noninvasive ventilatory support, administration of supplemental oxygen without correction of hypoventilation, inadequate low-pressure noninvasive ventilation, failure to use mechanical insufflation-exsufflation for airway clearance, and refusal to consider extubation to continuous noninvasive ventilatory support despite available published protocols. Across the cases, tracheostomy or death was often framed as inevitable, although feasible noninvasive alternatives existed. From a medicolegal perspective, these omissions raise concerns about breach of duty, failure to obtain informed consent, and loss of chance. The analysis suggests that customary practice is not necessarily reasonable practice when evidence-based alternatives are available and clinically applicable. For cognitively intact patients with ventilatory pump failure, acute-care teams should consider and document noninvasive ventilatory support and mechanical insufflation-exsufflation before proceeding to invasive or palliative pathways.
Experience-related neural dynamics in infants may be understood from a prediction-based perspective that incorporates bidirectional interactions between perception and expectation, modulated by sleep-wake states. This simulation study addresses two seemingly contradictory sets of fNIRS findings, which exhibit repetition-induced suppression or enhancement of neural response over trials, accompanied by correspondingly opposing surprise-induced responses. The simulation study demonstrates that, by interacting with tasks of varying complexity, a unified implicit, error-driven learning mechanism that engages both bottom-up perception and top-down expectation can simulate experience-related enhancements in perceptual and frontal responses. The distinction between trial-by-trial neural suppression and enhancement is then interpreted based on differing rates of neural attenuation influenced by the involvement of on- and/or off-task resources. In sleep states, a highly familiarized outcome with higher activation is responded to with shorter latency (decreasing on-task involvement), thus suppressing the overall neural response. In wakeful states, however, neural responses may be maintained by sustained attention but can still be subject to neural attenuation through novelty seeking (increasing off-task involvement). The simulation study raises questions about the interplay between the implicit prediction mechanism and (un)conscious states that contribute to experience-related neural dynamics in infants.
Dynamic thermo-mechanical stresses caused by sudden temperature changes and molten steel impact, etc., accelerate the degradation of Al2O3-C refractories during service. To investigate the dynamic degradation behavior, dynamic mechanical tests were conducted using the Split Hopkinson Pressure Bar (SHPB), systematically examining the effects of partial substitution of flake graphite by expanded graphite and thermal degradation. The results show that the Al2O3-C refractories exhibit a significant strain-rate hardening effect, with strength increasing with impact velocity and the failure mode progressively transitioning from crack propagation to pulverization. Cyclic prolonged thermal exposure to 1500 °C contributes to the SiC whiskers formation and densification, and results in the increase strength and brittleness. The phenomenon of specimen after 5 cycles having the optimal impact resistance proves the both the strength and energy dominated failure process. The introduction of expanded graphite effectively suppresses crack propagation and enhances energy dissipation capacity through interlayer sliding and stress buffering related to the myrmekitic texture, which provides a rationale for the development of low-carbon materials.
Radiotherapy’s clinical utility remains fundamentally constrained by the collateral damage to healthy tissues. Ultra-high dose rate (UHDR) irradiation, or FLASH-radiotherapy (FLASH-RT) has emerged as a transformative paradigm to mitigate such toxicity. However, the biological effects of FLASH-RT on the high-efficiency of tumor killing and normal tissue sparing remain poorly understood. In this work, we utilized a petawatt-class laser-plasma acceleration (LPA) platform to deliver discrete 12.9-nanosecond proton pulses at an extreme instantaneous dose rate of 1.94 × 107 Gy/s. This temporal singularity achieved a profound sparing effect in normal bronchial epithelial cells, evidenced by a nine-fold reduction in the lethal α coefficient (from 0.47 to 0.05 Gy−1), while maintaining full tumoricidal potency against lung adenocarcinoma. Mechanistically, we demonstrated that LPA-FLASH could effectively bypass the ATF3-mediated stress response and circumvent the subsequent ferroptotic cascade. This molecular evasion could preserve the mitochondrial cristae integrity and trigger an adaptive bioenergetic ATP surge—a hallmark of metabolic resilience exclusively in healthy tissue cells. Therefore, our findings identify ferroptosis-mediated mitochondrial integrity as a unifying framework for selective normal-tissue protection at the physical limits of radiation delivery, and establish LPA-FLASH-RT as a potent, compact modality for next-generation oncology.
