Radial expanding microchannels covered by copper foam were investigated as a passive pool-boiling surface designed to coordinate vapor discharge and liquid replenishment. The porous layer constrains unrestricted vertical bubble departure, allowing phase-change-induced bubble expansion to generate directional vapor motion along the radial channels, while its interconnected pores retain liquid close to the heated surface for rapid refilling after vapor passage. Pool-boiling experiments with deionized water near atmospheric pressure compared the performance of a plain copper surface, an expanding microchannel surface (ECS), and composite ECSs covered with copper-foam layers (ECS + CFL). The best composite configuration, which used 1-mm-thick, 20-PPI foam, reached a peak heat transfer coefficient (HTC) of 45 W/(cm²·K), 8.6 times the value for the plain surface, and increased the critical heat flux by a factor of 3.3. High-speed images showed elongated vapor regions oriented along the radial channels and liquid refilling after vapor discharge. The dependence on foam pore density and thickness indicates that the 20-PPI, 1-mm layer provided a better balance among bubble confinement, liquid availability, and transport resistance than the finer or thicker foams tested. In this paper, self-pumping refers to the observed sequence of directional vapor discharge and subsequent liquid refilling.
Polycaprolactone (PCL), despite its extensive use in biomedical engineering, is limited by its slow degradation and hydrophobic nature. To address these shortcomings and enhance its biological functionality, it is blended with poly(ethylene oxide) (PEO) and loaded with natural bioactive compounds, enhancing its hydrophilicity, electrospinnability, biodegradability, bioresponsiveness, and multifunctionality. Therefore, this study aimed to fabricate PCL/PEO optimized blended nanoscaffolds (BNS) incorporating betel leaf extracted particles (betel leaf extracts (BLE)) for the first time through electrospinning for applications in advanced tissue engineering and wound healing. BLE particles (725.08 +/- 224.22 nm) were obtained from Piper betle L. through maceration and sonication-assisted ethanolic extraction, followed by drying. Optimized PCL/PEO (10:1 w/w) blended solutions along with 10-30% (w/w relative to polymer) bioactive BLE were used to fabricate the desired scaffolds, and their physicochemical and mechanical properties were evaluated by scanning electron microscopy, fourier transform infrared, X-ray diffraction, thermogravimetric analysis, contact angle, swelling ratio, and tensile tests. In addition, antibacterial susceptibility, antioxidant activity, biodegradation, cell viability (A549 line), and in vitro wound closure assays were performed to assess the biological performance. The results demonstrated enhanced surface wettability with the fiber diameter increasing by 20.3-27.57% upon swelling. BLE-BNS exhibited 28-46.13% antioxidant activity, strong antibacterial effects, and acceptable biocompatibility. Notably, wound healing assays demonstrated 1.96-3.14-fold faster closure than the controls. These findings demonstrate that a BLE-loaded BNS is a multifunctional and fascinating choice for advanced wound healing and tissue engineering.
Telechelic polymers are known to form reversible networks through end-group association; however, their application as structuring agents in emulsion-based soft materials remains underexplored. Herein, we systematically investigate the biocompatible amphiphilic triblock copolymer poly(DL-lactic acid)-block-poly(ethylene oxide)-block-poly(DL-lactic acid)(PLA- b -PEO- b -PLA) as a rheology modifier in toluene-in-water model emulsions. Owing to the selective adsorption of PLA end blocks at the oil–water interface and the solvation of the PEO midblock in the aqueous phase, this polymer is expected to form reversible droplet-bridging networks. During the process, the polymer concentration, molecular weight of the mid and end blocks, and the dispersed phase volume fraction were adjusted, and the factors governing network formation were elucidated using oscillatory rheology and stress-relaxation measurements. The results show that anchoring of the PLA end blocks and PEO-mediated bridging predominantly control the strength and dynamic reversibility of the network. Step-strain experiments further reveal that the droplet-bridging interactions can be disrupted under large deformation and partially recover when small-strain conditions are restored, confirming the presence of reversible physical associations. These findings establish a molecular design strategy for biodegradable telechelic copolymers as effective and reprocessable structuring agents in emulsion gels. The shear-responsive, tunable, and reversible nature of the droplet-bridging network makes this material platform particularly suitable for injectable emulsion gels for advanced soft matter and biomedical engineering applications.
Recalcitrant nasal polyps are hallmarks of eosinophilic chronic rhinosinusitis, with abnormal fibrin deposition being critical for nasal polyp development. However, the specific cellular and molecular mechanisms underlying the pathogenesis of nasal polyps in patients with eosinophilic chronic rhinosinusitis remain poorly understood. To assess the impact of the renin-angiotensin system on eosinophilic chronic rhinosinusitis pathogenesis and identify new therapeutic targets. Renin-angiotensin system components, fibrin, tissue factor, and macrophages in nasal tissues were assessed using real-time polymerase chain reaction, enzyme-linked immunosorbent assay, immunohistochemistry, and immunofluorescence. Gene expression and protein levels were also analyzed in cultured THP-1 cells. In eosinophilic chronic rhinosinusitis nasal polyps, angiotensin-converting enzyme 2, Mas receptor, and angiotensin (1–7) were significantly reduced, while angiotensin II receptor type 1 was increased compared to non-eosinophilic chronic rhinosinusitis nasal polyps. This suggests angiotensin II/angiotensin II receptor type 1 axis predominance over the angiotensin (1–7)/Mas receptor axis in eosinophilic chronic rhinosinusitis. Immunofluorescence revealed profound fibrin deposition and increased tissue factor levels in eosinophilic chronic rhinosinusitis nasal polyps. M2 macrophages (CD68 + /CD163 +) were highly infiltrated, with most expressing tissue factor. Tissue factor expression was significantly increased in M2-polarized macrophages, and co-stimulation with angiotensin II further enhanced this expression. Renin-angiotensin system dysregulation might contribute to nasal polyp development in patients with eosinophilic chronic rhinosinusitis. Angiotensin II/angiotensin II receptor type 1 axis predominance over the angiotensin (1–7)/Mas receptor axis may enhance fibrin deposition by enhancing tissue factor expression in M2 macrophages, contributing to recalcitrant nasal polyp formation.
The investigation of molecular chirality within interlocked molecules is an appealing research area however, the synthesis of optically active interlocked molecules poses considerable challenges. In this study, we combined chiral spiroborate formation with the chiral recognition of secondary ammonium ions by a borate-containing crown macrocycle to synthesise optically active pseudo[2]rotaxanes from an achiral bis-catechol, chiral amines and boric acid. We examined how the chiral centres in amines influence the stereoselectivity of pseudo[2]rotaxanes under kinetic and thermodynamic conditions. Because the reversible borate-forming reaction creates a dynamic covalent bond between B and O, it facilitates the stereoselective formation of optically active pseudo[2]rotaxanes, achieving a diastereoselectivity of up to 40 : 1. After isolating the pseudo[2]rotaxanes, X-ray crystallography, circular dichroism spectroscopy and density functional theory calculations were used to reveal their absolute configuration.
