The increasing demand for compact and energy-efficient heat exchangers has accelerated the development of passive heat transfer enhancement techniques and intelligent predictive tools for improved thermal system design. In the present study, an experimental and machine learning-based investigation was conducted to evaluate the thermo-hydraulic performance of a counter-flow double-pipe heat exchanger equipped with helical wire coil (WC) inserts under turbulent flow conditions. The novelty of this work lies in the systematic assessment of fifteen insert configurations by combining three wire diameters (1.0, 1.5, and 2.0 mm) with five pitch ratios (P/Dc = 0.625, 1.25, 1.875, 2.5, and 3.125). Experiments were performed over a Reynolds number range of 5500-15000, and the experimental setup was validated against established Nusselt number and friction factor correlations. The thermo-hydraulic performance was evaluated using the heat transfer coefficient, Nusselt number, friction factor, pressure drop, and thermal performance factor. The results showed that the wire coil inserts generated strong swirl flow and secondary vortices, which enhanced fluid mixing and suppressed thermal boundary layer development, resulting in a maximum Nusselt number enhancement of 126.7% compared with the plain tube. The highest Nusselt number (180.24) was achieved using a 2 mm wire diameter with a P/Dc of 0.625. Although the friction factor increased by 156.5-410.8% due to greater flow resistance, the thermal performance factor remained above unity (1.01-1.35) for all configurations, confirming the overall thermo-hydraulic effectiveness of the inserts. Furthermore, Linear Regression, Ridge Regression, Random Forest, and Gradient Boosting models were developed to predict the heat transfer and flow characteristics. Among them, the Gradient Boosting model demonstrated the highest prediction accuracy, achieving R2 values of 0.9984 and 0.9971 for the Nusselt number and friction factor, respectively, highlighting the potential of machine learning for the rapid design and optimization of advanced heat exchanger systems.
Ischemic acute kidney injury (AKI) remains a major clinical challenge, characterized by high morbidity, mortality, and a substantial risk of progression to chronic kidney disease. Accumulating evidence indicates that ischemic AKI is not merely a transient hemodynamic disorder but a complex, biologically orchestrated process driven by microvascular dysfunction, innate immune activation, inflammatory signaling, and maladaptive tissue repair. Despite advances in supportive care, effective disease-modifying therapies are still lacking. Recent studies have highlighted that key signaling pathways, including Toll-like receptor/nuclear factor-κB (TLR/NF-κB), Janus kinase/signal transducer and activator of transcription (JAK/STAT), purinergic P2X7 receptor–inflammasome signaling, heat-shock protein–mediated stress responses, and phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) cascades, govern the initiation, amplification, and resolution of ischemic renal injury. These pathways converge on downstream cellular effectors such as cell adhesion molecules (CAMs), which orchestrate leukocyte recruitment, endothelial-epithelial interactions, and spatial propagation of inflammation within the renal microvasculature. Natural compounds have emerged as promising therapeutic candidates for ischemic AKI due to their pleiotropic pharmacological properties and ability to modulate multiple pathogenic signaling networks simultaneously. A growing body of experimental evidence demonstrates that polyphenols, glycosides, saponins, and related phytochemicals attenuate ischemic renal injury by suppressing inflammatory signaling, reducing CAM expression, preserving microcirculatory integrity, and promoting adaptive repair. Furthermore, advances in nanocarrier-based delivery systems have substantially enhanced the translational potential of these compounds by improving bioavailability, renal targeting, and pathway-specific modulation. In this review, we provide a comprehensive, signaling-centered analysis of ischemic AKI pathogenesis and systematically map natural compounds to their molecular targets and downstream inflammatory effectors. By integrating mechanistic insights with emerging nanotherapeutic strategies, this work offers a structured framework for the rational development of multi-target, mechanism-based interventions for ischemic AKI. It highlights key challenges and future directions for clinical translation.
The traditional renin-angiotensin system (RAS) is involved in the pathogenesis of glucocorticoid-induced osteoporosis (GIO). Combating the classical RAS cascade has a relevant therapeutic impact on osteoporosis. This study aimed to investigate the potential osteo-protective influence of diminazene, an angiotensin converting enzyme-2 (ACE-2) activator against GIO in rats. Forty adult male rats were equally classified into: control, GIO, diminazene, and GIO + diminazene groups. Rats were scanned via dual-energy X-ray absorptiometry for evaluation of bone mineral density (BMD) and bone mineral content (BMC). Serum levels of Ca2+, inorganic phosphorus (P), osteocalcin, bone-specific alkaline phosphatase (BALP) and tartrate-resistant acid phosphatase-5b (TRACP-5b) were measured. Bone receptor activator NF-kB ligand (RANKL), Osteoprotegerin (OPG), angiotensin II (Ang II), ACE-2, Ang (1–7), malondialdehyde (MDA), superoxide dismutase (SOD) activity, tumor necrosis factor-alpha (TNF-α) were determined. Additionally, femoral TNFSF11 and TNFRSF11B gene expression were evaluated through RT-PCR, as well as histopathological examination of rats’ femur and immunohistochemistry for assessment of femoral interleukin-6 (IL-6). Rats with GIO displayed diminished BMD and BMC with elevated serum BALP and TRACP-5b. Bone RANKL/OPG ratio and Ang II levels were also increased, while serum Ca2+, osteocalcin, bone ACE-2 and angiotensin (1–7) were apparently reduced. They displayed oxidant/antioxidant imbalance, increased bone TNF-α and IL-6, disturbed TNFSF11 and TNFRSF11B gene expression and histopathological osteoporotic changes. Diminazene improved BMD, BMC and bone metabolic markers. It reversed most of histopathological abnormalities. Alongside, it markedly increased bone ACE-2, Ang (1–7) and SOD activity, while decreasing bone RANKL/OPG ratio, Ang II, MDA, TNF-α and IL-6 with modification of TNFSF11 and TNFRSF11B genes. Diminazene, alleviated GIO via mediating anti-oxidant, anti-inflammatory actions together with modulation of RANKL/OPG pathway.
This study explores the development and characterization of novel polyvinyl chloride (PVC)/lead telluride (PbTe) nanocomposite films for advanced optoelectronic applications. PbTe nanopowder, synthesized via a hydrothermal method and exhibiting a cubic crystal structure with an average size of 18 nm, were incorporated into a PVC matrix at concentrations of 0.1, 0.2, and 0.3 wt
By depositing polypyrrole (PPy) onto methylcellulose (MC) and carbon (C) nanoparticles using cyclic voltammetry electrochemical polymerization, a flexible supercapacitor electrode was created. The 4-probe technique boosted electrical conductivity by four orders of magnitude with C content. MCC-6, a nanocomposite with a C/MC ratio of 6/94, was chosen for the supercapacitor electrode substrate due to its high electrical conductivity. Electrochemical investigations showed that TiO2 nanoparticles improved electrode performance. MCC-6/PPy and MCC-6/PPy-TiO2 achieved areal capacitance values of 189.22 and 455.36 mF cm−2, respectively, at 5 mV/s using cyclic voltammetry. Galvanostatic charge–discharge experiments showed that MCC-6/PPy-TiO2 had higher areal capacitance values than MCC-6/PPy at various current densities. At a current density of 4 mA cm−2, MCC-6/PPy and MCC-6/PPy-TiO2 attained maximum areal capacitance values of 188.91 and 757.15 mF cm−2, respectively. Power-law analysis and Dunn’s approach demonstrated that the MCC-6/PPy-TiO₂ electrode displays a mixed charge storage mechanism with a markedly greater capacitive contribution than MCC-6/PPy, signifying enhanced surface-controlled electrochemical processes. The MCC-6/PPy-TiO2 electrode exhibited superior Coulombic efficiency (92.4–93.5
